1	//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This file implements the Expr constant evaluator.
10	//
11	// Constant expression evaluation produces four main results:
12	//
13	// * A success/failure flag indicating whether constant folding was successful.
14	// This is the 'bool' return value used by most of the code in this file. A
15	// 'false' return value indicates that constant folding has failed, and any
16	// appropriate diagnostic has already been produced.
17	//
18	// * An evaluated result, valid only if constant folding has not failed.
19	//
20	// * A flag indicating if evaluation encountered (unevaluated) side-effects.
21	// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22	// where it is possible to determine the evaluated result regardless.
23	//
24	// * A set of notes indicating why the evaluation was not a constant expression
25	// (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26	// too, why the expression could not be folded.
27	//
28	// If we are checking for a potential constant expression, failure to constant
29	// fold a potential constant sub-expression will be indicated by a 'false'
30	// return value (the expression could not be folded) and no diagnostic (the
31	// expression is not necessarily non-constant).
32	//
33	//===----------------------------------------------------------------------===//
34
35	#include "ExprConstShared.h"
36	#include "Interp/Context.h"
37	#include "Interp/Frame.h"
38	#include "Interp/State.h"
39	#include "clang/AST/APValue.h"
40	#include "clang/AST/ASTContext.h"
41	#include "clang/AST/ASTDiagnostic.h"
42	#include "clang/AST/ASTLambda.h"
43	#include "clang/AST/Attr.h"
44	#include "clang/AST/CXXInheritance.h"
45	#include "clang/AST/CharUnits.h"
46	#include "clang/AST/CurrentSourceLocExprScope.h"
47	#include "clang/AST/Expr.h"
48	#include "clang/AST/OSLog.h"
49	#include "clang/AST/OptionalDiagnostic.h"
50	#include "clang/AST/RecordLayout.h"
51	#include "clang/AST/StmtVisitor.h"
52	#include "clang/AST/TypeLoc.h"
53	#include "clang/Basic/Builtins.h"
54	#include "clang/Basic/DiagnosticSema.h"
55	#include "clang/Basic/TargetInfo.h"
56	#include "llvm/ADT/APFixedPoint.h"
57	#include "llvm/ADT/SmallBitVector.h"
58	#include "llvm/ADT/StringExtras.h"
59	#include "llvm/Support/Debug.h"
60	#include "llvm/Support/SaveAndRestore.h"
61	#include "llvm/Support/TimeProfiler.h"
62	#include "llvm/Support/raw_ostream.h"
63	#include <cstring>
64	#include <functional>
65	#include <optional>
66
67	#define DEBUG_TYPE "exprconstant"
68
69	using namespace clang;
70	using llvm::APFixedPoint;
71	using llvm::APInt;
72	using llvm::APSInt;
73	using llvm::APFloat;
74	using llvm::FixedPointSemantics;
75
76	namespace {
77	struct LValue;
78	class CallStackFrame;
79	class EvalInfo;
80
81	using SourceLocExprScopeGuard =
82	CurrentSourceLocExprScope::SourceLocExprScopeGuard;
83
84	static QualType getType(APValue::LValueBase B) {
85	return B.getType();
86	}
87
88	/// Get an LValue path entry, which is known to not be an array index, as a
89	/// field declaration.
90	static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
91	return dyn_cast_or_null<FieldDecl>(Val: E.getAsBaseOrMember().getPointer());
92	}
93	/// Get an LValue path entry, which is known to not be an array index, as a
94	/// base class declaration.
95	static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
96	return dyn_cast_or_null<CXXRecordDecl>(Val: E.getAsBaseOrMember().getPointer());
97	}
98	/// Determine whether this LValue path entry for a base class names a virtual
99	/// base class.
100	static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
101	return E.getAsBaseOrMember().getInt();
102	}
103
104	/// Given an expression, determine the type used to store the result of
105	/// evaluating that expression.
106	static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
107	if (E->isPRValue())
108	return E->getType();
109	return Ctx.getLValueReferenceType(T: E->getType());
110	}
111
112	/// Given a CallExpr, try to get the alloc_size attribute. May return null.
113	static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
114	if (const FunctionDecl *DirectCallee = CE->getDirectCallee())
115	return DirectCallee->getAttr<AllocSizeAttr>();
116	if (const Decl *IndirectCallee = CE->getCalleeDecl())
117	return IndirectCallee->getAttr<AllocSizeAttr>();
118	return nullptr;
119	}
120
121	/// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
122	/// This will look through a single cast.
123	///
124	/// Returns null if we couldn't unwrap a function with alloc_size.
125	static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
126	if (!E->getType()->isPointerType())
127	return nullptr;
128
129	E = E->IgnoreParens();
130	// If we're doing a variable assignment from e.g. malloc(N), there will
131	// probably be a cast of some kind. In exotic cases, we might also see a
132	// top-level ExprWithCleanups. Ignore them either way.
133	if (const auto *FE = dyn_cast<FullExpr>(Val: E))
134	E = FE->getSubExpr()->IgnoreParens();
135
136	if (const auto *Cast = dyn_cast<CastExpr>(Val: E))
137	E = Cast->getSubExpr()->IgnoreParens();
138
139	if (const auto *CE = dyn_cast<CallExpr>(E))
140	return getAllocSizeAttr(CE) ? CE : nullptr;
141	return nullptr;
142	}
143
144	/// Determines whether or not the given Base contains a call to a function
145	/// with the alloc_size attribute.
146	static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
147	const auto *E = Base.dyn_cast<const Expr *>();
148	return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
149	}
150
151	/// Determines whether the given kind of constant expression is only ever
152	/// used for name mangling. If so, it's permitted to reference things that we
153	/// can't generate code for (in particular, dllimported functions).
154	static bool isForManglingOnly(ConstantExprKind Kind) {
155	switch (Kind) {
156	case ConstantExprKind::Normal:
157	case ConstantExprKind::ClassTemplateArgument:
158	case ConstantExprKind::ImmediateInvocation:
159	// Note that non-type template arguments of class type are emitted as
160	// template parameter objects.
161	return false;
162
163	case ConstantExprKind::NonClassTemplateArgument:
164	return true;
165	}
166	llvm_unreachable("unknown ConstantExprKind");
167	}
168
169	static bool isTemplateArgument(ConstantExprKind Kind) {
170	switch (Kind) {
171	case ConstantExprKind::Normal:
172	case ConstantExprKind::ImmediateInvocation:
173	return false;
174
175	case ConstantExprKind::ClassTemplateArgument:
176	case ConstantExprKind::NonClassTemplateArgument:
177	return true;
178	}
179	llvm_unreachable("unknown ConstantExprKind");
180	}
181
182	/// The bound to claim that an array of unknown bound has.
183	/// The value in MostDerivedArraySize is undefined in this case. So, set it
184	/// to an arbitrary value that's likely to loudly break things if it's used.
185	static const uint64_t AssumedSizeForUnsizedArray =
186	std::numeric_limits<uint64_t>::max() / 2;
187
188	/// Determines if an LValue with the given LValueBase will have an unsized
189	/// array in its designator.
190	/// Find the path length and type of the most-derived subobject in the given
191	/// path, and find the size of the containing array, if any.
192	static unsigned
193	findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
194	ArrayRef<APValue::LValuePathEntry> Path,
195	uint64_t &ArraySize, QualType &Type, bool &IsArray,
196	bool &FirstEntryIsUnsizedArray) {
197	// This only accepts LValueBases from APValues, and APValues don't support
198	// arrays that lack size info.
199	assert(!isBaseAnAllocSizeCall(Base) &&
200	"Unsized arrays shouldn't appear here");
201	unsigned MostDerivedLength = 0;
202	Type = getType(B: Base);
203
204	for (unsigned I = 0, N = Path.size(); I != N; ++I) {
205	if (Type->isArrayType()) {
206	const ArrayType *AT = Ctx.getAsArrayType(T: Type);
207	Type = AT->getElementType();
208	MostDerivedLength = I + 1;
209	IsArray = true;
210
211	if (auto *CAT = dyn_cast<ConstantArrayType>(Val: AT)) {
212	ArraySize = CAT->getZExtSize();
213	} else {
214	assert(I == 0 && "unexpected unsized array designator");
215	FirstEntryIsUnsizedArray = true;
216	ArraySize = AssumedSizeForUnsizedArray;
217	}
218	} else if (Type->isAnyComplexType()) {
219	const ComplexType *CT = Type->castAs<ComplexType>();
220	Type = CT->getElementType();
221	ArraySize = 2;
222	MostDerivedLength = I + 1;
223	IsArray = true;
224	} else if (const FieldDecl *FD = getAsField(E: Path[I])) {
225	Type = FD->getType();
226	ArraySize = 0;
227	MostDerivedLength = I + 1;
228	IsArray = false;
229	} else {
230	// Path[I] describes a base class.
231	ArraySize = 0;
232	IsArray = false;
233	}
234	}
235	return MostDerivedLength;
236	}
237
238	/// A path from a glvalue to a subobject of that glvalue.
239	struct SubobjectDesignator {
240	/// True if the subobject was named in a manner not supported by C++11. Such
241	/// lvalues can still be folded, but they are not core constant expressions
242	/// and we cannot perform lvalue-to-rvalue conversions on them.
243	LLVM_PREFERRED_TYPE(bool)
244	unsigned Invalid : 1;
245
246	/// Is this a pointer one past the end of an object?
247	LLVM_PREFERRED_TYPE(bool)
248	unsigned IsOnePastTheEnd : 1;
249
250	/// Indicator of whether the first entry is an unsized array.
251	LLVM_PREFERRED_TYPE(bool)
252	unsigned FirstEntryIsAnUnsizedArray : 1;
253
254	/// Indicator of whether the most-derived object is an array element.
255	LLVM_PREFERRED_TYPE(bool)
256	unsigned MostDerivedIsArrayElement : 1;
257
258	/// The length of the path to the most-derived object of which this is a
259	/// subobject.
260	unsigned MostDerivedPathLength : 28;
261
262	/// The size of the array of which the most-derived object is an element.
263	/// This will always be 0 if the most-derived object is not an array
264	/// element. 0 is not an indicator of whether or not the most-derived object
265	/// is an array, however, because 0-length arrays are allowed.
266	///
267	/// If the current array is an unsized array, the value of this is
268	/// undefined.
269	uint64_t MostDerivedArraySize;
270
271	/// The type of the most derived object referred to by this address.
272	QualType MostDerivedType;
273
274	typedef APValue::LValuePathEntry PathEntry;
275
276	/// The entries on the path from the glvalue to the designated subobject.
277	SmallVector<PathEntry, 8> Entries;
278
279	SubobjectDesignator() : Invalid(true) {}
280
281	explicit SubobjectDesignator(QualType T)
282	: Invalid(false), IsOnePastTheEnd(false),
283	FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
284	MostDerivedPathLength(0), MostDerivedArraySize(0),
285	MostDerivedType(T) {}
286
287	SubobjectDesignator(ASTContext &Ctx, const APValue &V)
288	: Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
289	FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
290	MostDerivedPathLength(0), MostDerivedArraySize(0) {
291	assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
292	if (!Invalid) {
293	IsOnePastTheEnd = V.isLValueOnePastTheEnd();
294	ArrayRef<PathEntry> VEntries = V.getLValuePath();
295	Entries.insert(I: Entries.end(), From: VEntries.begin(), To: VEntries.end());
296	if (V.getLValueBase()) {
297	bool IsArray = false;
298	bool FirstIsUnsizedArray = false;
299	MostDerivedPathLength = findMostDerivedSubobject(
300	Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
301	MostDerivedType, IsArray, FirstIsUnsizedArray);
302	MostDerivedIsArrayElement = IsArray;
303	FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
304	}
305	}
306	}
307
308	void truncate(ASTContext &Ctx, APValue::LValueBase Base,
309	unsigned NewLength) {
310	if (Invalid)
311	return;
312
313	assert(Base && "cannot truncate path for null pointer");
314	assert(NewLength <= Entries.size() && "not a truncation");
315
316	if (NewLength == Entries.size())
317	return;
318	Entries.resize(N: NewLength);
319
320	bool IsArray = false;
321	bool FirstIsUnsizedArray = false;
322	MostDerivedPathLength = findMostDerivedSubobject(
323	Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray,
324	FirstIsUnsizedArray);
325	MostDerivedIsArrayElement = IsArray;
326	FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
327	}
328
329	void setInvalid() {
330	Invalid = true;
331	Entries.clear();
332	}
333
334	/// Determine whether the most derived subobject is an array without a
335	/// known bound.
336	bool isMostDerivedAnUnsizedArray() const {
337	assert(!Invalid && "Calling this makes no sense on invalid designators");
338	return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
339	}
340
341	/// Determine what the most derived array's size is. Results in an assertion
342	/// failure if the most derived array lacks a size.
343	uint64_t getMostDerivedArraySize() const {
344	assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size");
345	return MostDerivedArraySize;
346	}
347
348	/// Determine whether this is a one-past-the-end pointer.
349	bool isOnePastTheEnd() const {
350	assert(!Invalid);
351	if (IsOnePastTheEnd)
352	return true;
353	if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
354	Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
355	MostDerivedArraySize)
356	return true;
357	return false;
358	}
359
360	/// Get the range of valid index adjustments in the form
361	/// {maximum value that can be subtracted from this pointer,
362	/// maximum value that can be added to this pointer}
363	std::pair<uint64_t, uint64_t> validIndexAdjustments() {
364	if (Invalid || isMostDerivedAnUnsizedArray())
365	return {0, 0};
366
367	// [expr.add]p4: For the purposes of these operators, a pointer to a
368	// nonarray object behaves the same as a pointer to the first element of
369	// an array of length one with the type of the object as its element type.
370	bool IsArray = MostDerivedPathLength == Entries.size() &&
371	MostDerivedIsArrayElement;
372	uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
373	: (uint64_t)IsOnePastTheEnd;
374	uint64_t ArraySize =
375	IsArray ? getMostDerivedArraySize() : (uint64_t)1;
376	return {ArrayIndex, ArraySize - ArrayIndex};
377	}
378
379	/// Check that this refers to a valid subobject.
380	bool isValidSubobject() const {
381	if (Invalid)
382	return false;
383	return !isOnePastTheEnd();
384	}
385	/// Check that this refers to a valid subobject, and if not, produce a
386	/// relevant diagnostic and set the designator as invalid.
387	bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
388
389	/// Get the type of the designated object.
390	QualType getType(ASTContext &Ctx) const {
391	assert(!Invalid && "invalid designator has no subobject type");
392	return MostDerivedPathLength == Entries.size()
393	? MostDerivedType
394	: Ctx.getRecordType(getAsBaseClass(Entries.back()));
395	}
396
397	/// Update this designator to refer to the first element within this array.
398	void addArrayUnchecked(const ConstantArrayType *CAT) {
399	Entries.push_back(Elt: PathEntry::ArrayIndex(Index: 0));
400
401	// This is a most-derived object.
402	MostDerivedType = CAT->getElementType();
403	MostDerivedIsArrayElement = true;
404	MostDerivedArraySize = CAT->getZExtSize();
405	MostDerivedPathLength = Entries.size();
406	}
407	/// Update this designator to refer to the first element within the array of
408	/// elements of type T. This is an array of unknown size.
409	void addUnsizedArrayUnchecked(QualType ElemTy) {
410	Entries.push_back(Elt: PathEntry::ArrayIndex(Index: 0));
411
412	MostDerivedType = ElemTy;
413	MostDerivedIsArrayElement = true;
414	// The value in MostDerivedArraySize is undefined in this case. So, set it
415	// to an arbitrary value that's likely to loudly break things if it's
416	// used.
417	MostDerivedArraySize = AssumedSizeForUnsizedArray;
418	MostDerivedPathLength = Entries.size();
419	}
420	/// Update this designator to refer to the given base or member of this
421	/// object.
422	void addDeclUnchecked(const Decl *D, bool Virtual = false) {
423	Entries.push_back(Elt: APValue::BaseOrMemberType(D, Virtual));
424
425	// If this isn't a base class, it's a new most-derived object.
426	if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: D)) {
427	MostDerivedType = FD->getType();
428	MostDerivedIsArrayElement = false;
429	MostDerivedArraySize = 0;
430	MostDerivedPathLength = Entries.size();
431	}
432	}
433	/// Update this designator to refer to the given complex component.
434	void addComplexUnchecked(QualType EltTy, bool Imag) {
435	Entries.push_back(Elt: PathEntry::ArrayIndex(Index: Imag));
436
437	// This is technically a most-derived object, though in practice this
438	// is unlikely to matter.
439	MostDerivedType = EltTy;
440	MostDerivedIsArrayElement = true;
441	MostDerivedArraySize = 2;
442	MostDerivedPathLength = Entries.size();
443	}
444	void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
445	void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
446	const APSInt &N);
447	/// Add N to the address of this subobject.
448	void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
449	if (Invalid || !N) return;
450	uint64_t TruncatedN = N.extOrTrunc(width: 64).getZExtValue();
451	if (isMostDerivedAnUnsizedArray()) {
452	diagnoseUnsizedArrayPointerArithmetic(Info, E);
453	// Can't verify -- trust that the user is doing the right thing (or if
454	// not, trust that the caller will catch the bad behavior).
455	// FIXME: Should we reject if this overflows, at least?
456	Entries.back() = PathEntry::ArrayIndex(
457	Index: Entries.back().getAsArrayIndex() + TruncatedN);
458	return;
459	}
460
461	// [expr.add]p4: For the purposes of these operators, a pointer to a
462	// nonarray object behaves the same as a pointer to the first element of
463	// an array of length one with the type of the object as its element type.
464	bool IsArray = MostDerivedPathLength == Entries.size() &&
465	MostDerivedIsArrayElement;
466	uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
467	: (uint64_t)IsOnePastTheEnd;
468	uint64_t ArraySize =
469	IsArray ? getMostDerivedArraySize() : (uint64_t)1;
470
471	if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
472	// Calculate the actual index in a wide enough type, so we can include
473	// it in the note.
474	N = N.extend(width: std::max<unsigned>(a: N.getBitWidth() + 1, b: 65));
475	(llvm::APInt&)N += ArrayIndex;
476	assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
477	diagnosePointerArithmetic(Info, E, N);
478	setInvalid();
479	return;
480	}
481
482	ArrayIndex += TruncatedN;
483	assert(ArrayIndex <= ArraySize &&
484	"bounds check succeeded for out-of-bounds index");
485
486	if (IsArray)
487	Entries.back() = PathEntry::ArrayIndex(Index: ArrayIndex);
488	else
489	IsOnePastTheEnd = (ArrayIndex != 0);
490	}
491	};
492
493	/// A scope at the end of which an object can need to be destroyed.
494	enum class ScopeKind {
495	Block,
496	FullExpression,
497	Call
498	};
499
500	/// A reference to a particular call and its arguments.
501	struct CallRef {
502	CallRef() : OrigCallee(), CallIndex(0), Version() {}
503	CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version)
504	: OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {}
505
506	explicit operator bool() const { return OrigCallee; }
507
508	/// Get the parameter that the caller initialized, corresponding to the
509	/// given parameter in the callee.
510	const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const {
511	return OrigCallee ? OrigCallee->getParamDecl(i: PVD->getFunctionScopeIndex())
512	: PVD;
513	}
514
515	/// The callee at the point where the arguments were evaluated. This might
516	/// be different from the actual callee (a different redeclaration, or a
517	/// virtual override), but this function's parameters are the ones that
518	/// appear in the parameter map.
519	const FunctionDecl *OrigCallee;
520	/// The call index of the frame that holds the argument values.
521	unsigned CallIndex;
522	/// The version of the parameters corresponding to this call.
523	unsigned Version;
524	};
525
526	/// A stack frame in the constexpr call stack.
527	class CallStackFrame : public interp::Frame {
528	public:
529	EvalInfo &Info;
530
531	/// Parent - The caller of this stack frame.
532	CallStackFrame *Caller;
533
534	/// Callee - The function which was called.
535	const FunctionDecl *Callee;
536
537	/// This - The binding for the this pointer in this call, if any.
538	const LValue *This;
539
540	/// CallExpr - The syntactical structure of member function calls
541	const Expr *CallExpr;
542
543	/// Information on how to find the arguments to this call. Our arguments
544	/// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a
545	/// key and this value as the version.
546	CallRef Arguments;
547
548	/// Source location information about the default argument or default
549	/// initializer expression we're evaluating, if any.
550	CurrentSourceLocExprScope CurSourceLocExprScope;
551
552	// Note that we intentionally use std::map here so that references to
553	// values are stable.
554	typedef std::pair<const void *, unsigned> MapKeyTy;
555	typedef std::map<MapKeyTy, APValue> MapTy;
556	/// Temporaries - Temporary lvalues materialized within this stack frame.
557	MapTy Temporaries;
558
559	/// CallRange - The source range of the call expression for this call.
560	SourceRange CallRange;
561
562	/// Index - The call index of this call.
563	unsigned Index;
564
565	/// The stack of integers for tracking version numbers for temporaries.
566	SmallVector<unsigned, 2> TempVersionStack = {1};
567	unsigned CurTempVersion = TempVersionStack.back();
568
569	unsigned getTempVersion() const { return TempVersionStack.back(); }
570
571	void pushTempVersion() {
572	TempVersionStack.push_back(Elt: ++CurTempVersion);
573	}
574
575	void popTempVersion() {
576	TempVersionStack.pop_back();
577	}
578
579	CallRef createCall(const FunctionDecl *Callee) {
580	return {Callee, Index, ++CurTempVersion};
581	}
582
583	// FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
584	// on the overall stack usage of deeply-recursing constexpr evaluations.
585	// (We should cache this map rather than recomputing it repeatedly.)
586	// But let's try this and see how it goes; we can look into caching the map
587	// as a later change.
588
589	/// LambdaCaptureFields - Mapping from captured variables/this to
590	/// corresponding data members in the closure class.
591	llvm::DenseMap<const ValueDecl *, FieldDecl *> LambdaCaptureFields;
592	FieldDecl *LambdaThisCaptureField = nullptr;
593
594	CallStackFrame(EvalInfo &Info, SourceRange CallRange,
595	const FunctionDecl *Callee, const LValue *This,
596	const Expr *CallExpr, CallRef Arguments);
597	~CallStackFrame();
598
599	// Return the temporary for Key whose version number is Version.
600	APValue *getTemporary(const void *Key, unsigned Version) {
601	MapKeyTy KV(Key, Version);
602	auto LB = Temporaries.lower_bound(x: KV);
603	if (LB != Temporaries.end() && LB->first == KV)
604	return &LB->second;
605	return nullptr;
606	}
607
608	// Return the current temporary for Key in the map.
609	APValue *getCurrentTemporary(const void *Key) {
610	auto UB = Temporaries.upper_bound(x: MapKeyTy(Key, UINT_MAX));
611	if (UB != Temporaries.begin() && std::prev(x: UB)->first.first == Key)
612	return &std::prev(x: UB)->second;
613	return nullptr;
614	}
615
616	// Return the version number of the current temporary for Key.
617	unsigned getCurrentTemporaryVersion(const void *Key) const {
618	auto UB = Temporaries.upper_bound(x: MapKeyTy(Key, UINT_MAX));
619	if (UB != Temporaries.begin() && std::prev(x: UB)->first.first == Key)
620	return std::prev(x: UB)->first.second;
621	return 0;
622	}
623
624	/// Allocate storage for an object of type T in this stack frame.
625	/// Populates LV with a handle to the created object. Key identifies
626	/// the temporary within the stack frame, and must not be reused without
627	/// bumping the temporary version number.
628	template<typename KeyT>
629	APValue &createTemporary(const KeyT *Key, QualType T,
630	ScopeKind Scope, LValue &LV);
631
632	/// Allocate storage for a parameter of a function call made in this frame.
633	APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);
634
635	void describe(llvm::raw_ostream &OS) const override;
636
637	Frame *getCaller() const override { return Caller; }
638	SourceRange getCallRange() const override { return CallRange; }
639	const FunctionDecl *getCallee() const override { return Callee; }
640
641	bool isStdFunction() const {
642	for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
643	if (DC->isStdNamespace())
644	return true;
645	return false;
646	}
647
648	/// Whether we're in a context where [[msvc::constexpr]] evaluation is
649	/// permitted. See MSConstexprDocs for description of permitted contexts.
650	bool CanEvalMSConstexpr = false;
651
652	private:
653	APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T,
654	ScopeKind Scope);
655	};
656
657	/// Temporarily override 'this'.
658	class ThisOverrideRAII {
659	public:
660	ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
661	: Frame(Frame), OldThis(Frame.This) {
662	if (Enable)
663	Frame.This = NewThis;
664	}
665	~ThisOverrideRAII() {
666	Frame.This = OldThis;
667	}
668	private:
669	CallStackFrame &Frame;
670	const LValue *OldThis;
671	};
672
673	// A shorthand time trace scope struct, prints source range, for example
674	// {"name":"EvaluateAsRValue","args":{"detail":"<test.cc:8:21, col:25>"}}}
675	class ExprTimeTraceScope {
676	public:
677	ExprTimeTraceScope(const Expr *E, const ASTContext &Ctx, StringRef Name)
678	: TimeScope(Name, [E, &Ctx] {
679	return E->getSourceRange().printToString(Ctx.getSourceManager());
680	}) {}
681
682	private:
683	llvm::TimeTraceScope TimeScope;
684	};
685
686	/// RAII object used to change the current ability of
687	/// [[msvc::constexpr]] evaulation.
688	struct MSConstexprContextRAII {
689	CallStackFrame &Frame;
690	bool OldValue;
691	explicit MSConstexprContextRAII(CallStackFrame &Frame, bool Value)
692	: Frame(Frame), OldValue(Frame.CanEvalMSConstexpr) {
693	Frame.CanEvalMSConstexpr = Value;
694	}
695
696	~MSConstexprContextRAII() { Frame.CanEvalMSConstexpr = OldValue; }
697	};
698	}
699
700	static bool HandleDestruction(EvalInfo &Info, const Expr *E,
701	const LValue &This, QualType ThisType);
702	static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
703	APValue::LValueBase LVBase, APValue &Value,
704	QualType T);
705
706	namespace {
707	/// A cleanup, and a flag indicating whether it is lifetime-extended.
708	class Cleanup {
709	llvm::PointerIntPair<APValue*, 2, ScopeKind> Value;
710	APValue::LValueBase Base;
711	QualType T;
712
713	public:
714	Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
715	ScopeKind Scope)
716	: Value(Val, Scope), Base(Base), T(T) {}
717
718	/// Determine whether this cleanup should be performed at the end of the
719	/// given kind of scope.
720	bool isDestroyedAtEndOf(ScopeKind K) const {
721	return (int)Value.getInt() >= (int)K;
722	}
723	bool endLifetime(EvalInfo &Info, bool RunDestructors) {
724	if (RunDestructors) {
725	SourceLocation Loc;
726	if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
727	Loc = VD->getLocation();
728	else if (const Expr *E = Base.dyn_cast<const Expr*>())
729	Loc = E->getExprLoc();
730	return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T);
731	}
732	*Value.getPointer() = APValue();
733	return true;
734	}
735
736	bool hasSideEffect() {
737	return T.isDestructedType();
738	}
739	};
740
741	/// A reference to an object whose construction we are currently evaluating.
742	struct ObjectUnderConstruction {
743	APValue::LValueBase Base;
744	ArrayRef<APValue::LValuePathEntry> Path;
745	friend bool operator==(const ObjectUnderConstruction &LHS,
746	const ObjectUnderConstruction &RHS) {
747	return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
748	}
749	friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
750	return llvm::hash_combine(args: Obj.Base, args: Obj.Path);
751	}
752	};
753	enum class ConstructionPhase {
754	None,
755	Bases,
756	AfterBases,
757	AfterFields,
758	Destroying,
759	DestroyingBases
760	};
761	}
762
763	namespace llvm {
764	template<> struct DenseMapInfo<ObjectUnderConstruction> {
765	using Base = DenseMapInfo<APValue::LValueBase>;
766	static ObjectUnderConstruction getEmptyKey() {
767	return {.Base: Base::getEmptyKey(), .Path: {}}; }
768	static ObjectUnderConstruction getTombstoneKey() {
769	return {.Base: Base::getTombstoneKey(), .Path: {}};
770	}
771	static unsigned getHashValue(const ObjectUnderConstruction &Object) {
772	return hash_value(Obj: Object);
773	}
774	static bool isEqual(const ObjectUnderConstruction &LHS,
775	const ObjectUnderConstruction &RHS) {
776	return LHS == RHS;
777	}
778	};
779	}
780
781	namespace {
782	/// A dynamically-allocated heap object.
783	struct DynAlloc {
784	/// The value of this heap-allocated object.
785	APValue Value;
786	/// The allocating expression; used for diagnostics. Either a CXXNewExpr
787	/// or a CallExpr (the latter is for direct calls to operator new inside
788	/// std::allocator<T>::allocate).
789	const Expr *AllocExpr = nullptr;
790
791	enum Kind {
792	New,
793	ArrayNew,
794	StdAllocator
795	};
796
797	/// Get the kind of the allocation. This must match between allocation
798	/// and deallocation.
799	Kind getKind() const {
800	if (auto *NE = dyn_cast<CXXNewExpr>(Val: AllocExpr))
801	return NE->isArray() ? ArrayNew : New;
802	assert(isa<CallExpr>(AllocExpr));
803	return StdAllocator;
804	}
805	};
806
807	struct DynAllocOrder {
808	bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
809	return L.getIndex() < R.getIndex();
810	}
811	};
812
813	/// EvalInfo - This is a private struct used by the evaluator to capture
814	/// information about a subexpression as it is folded. It retains information
815	/// about the AST context, but also maintains information about the folded
816	/// expression.
817	///
818	/// If an expression could be evaluated, it is still possible it is not a C
819	/// "integer constant expression" or constant expression. If not, this struct
820	/// captures information about how and why not.
821	///
822	/// One bit of information passed *into* the request for constant folding
823	/// indicates whether the subexpression is "evaluated" or not according to C
824	/// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
825	/// evaluate the expression regardless of what the RHS is, but C only allows
826	/// certain things in certain situations.
827	class EvalInfo : public interp::State {
828	public:
829	ASTContext &Ctx;
830
831	/// EvalStatus - Contains information about the evaluation.
832	Expr::EvalStatus &EvalStatus;
833
834	/// CurrentCall - The top of the constexpr call stack.
835	CallStackFrame *CurrentCall;
836
837	/// CallStackDepth - The number of calls in the call stack right now.
838	unsigned CallStackDepth;
839
840	/// NextCallIndex - The next call index to assign.
841	unsigned NextCallIndex;
842
843	/// StepsLeft - The remaining number of evaluation steps we're permitted
844	/// to perform. This is essentially a limit for the number of statements
845	/// we will evaluate.
846	unsigned StepsLeft;
847
848	/// Enable the experimental new constant interpreter. If an expression is
849	/// not supported by the interpreter, an error is triggered.
850	bool EnableNewConstInterp;
851
852	/// BottomFrame - The frame in which evaluation started. This must be
853	/// initialized after CurrentCall and CallStackDepth.
854	CallStackFrame BottomFrame;
855
856	/// A stack of values whose lifetimes end at the end of some surrounding
857	/// evaluation frame.
858	llvm::SmallVector<Cleanup, 16> CleanupStack;
859
860	/// EvaluatingDecl - This is the declaration whose initializer is being
861	/// evaluated, if any.
862	APValue::LValueBase EvaluatingDecl;
863
864	enum class EvaluatingDeclKind {
865	None,
866	/// We're evaluating the construction of EvaluatingDecl.
867	Ctor,
868	/// We're evaluating the destruction of EvaluatingDecl.
869	Dtor,
870	};
871	EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;
872
873	/// EvaluatingDeclValue - This is the value being constructed for the
874	/// declaration whose initializer is being evaluated, if any.
875	APValue *EvaluatingDeclValue;
876
877	/// Set of objects that are currently being constructed.
878	llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
879	ObjectsUnderConstruction;
880
881	/// Current heap allocations, along with the location where each was
882	/// allocated. We use std::map here because we need stable addresses
883	/// for the stored APValues.
884	std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;
885
886	/// The number of heap allocations performed so far in this evaluation.
887	unsigned NumHeapAllocs = 0;
888
889	struct EvaluatingConstructorRAII {
890	EvalInfo &EI;
891	ObjectUnderConstruction Object;
892	bool DidInsert;
893	EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
894	bool HasBases)
895	: EI(EI), Object(Object) {
896	DidInsert =
897	EI.ObjectsUnderConstruction
898	.insert(KV: {Object, HasBases ? ConstructionPhase::Bases
899	: ConstructionPhase::AfterBases})
900	.second;
901	}
902	void finishedConstructingBases() {
903	EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
904	}
905	void finishedConstructingFields() {
906	EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
907	}
908	~EvaluatingConstructorRAII() {
909	if (DidInsert) EI.ObjectsUnderConstruction.erase(Val: Object);
910	}
911	};
912
913	struct EvaluatingDestructorRAII {
914	EvalInfo &EI;
915	ObjectUnderConstruction Object;
916	bool DidInsert;
917	EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
918	: EI(EI), Object(Object) {
919	DidInsert = EI.ObjectsUnderConstruction
920	.insert(KV: {Object, ConstructionPhase::Destroying})
921	.second;
922	}
923	void startedDestroyingBases() {
924	EI.ObjectsUnderConstruction[Object] =
925	ConstructionPhase::DestroyingBases;
926	}
927	~EvaluatingDestructorRAII() {
928	if (DidInsert)
929	EI.ObjectsUnderConstruction.erase(Val: Object);
930	}
931	};
932
933	ConstructionPhase
934	isEvaluatingCtorDtor(APValue::LValueBase Base,
935	ArrayRef<APValue::LValuePathEntry> Path) {
936	return ObjectsUnderConstruction.lookup(Val: {.Base: Base, .Path: Path});
937	}
938
939	/// If we're currently speculatively evaluating, the outermost call stack
940	/// depth at which we can mutate state, otherwise 0.
941	unsigned SpeculativeEvaluationDepth = 0;
942
943	/// The current array initialization index, if we're performing array
944	/// initialization.
945	uint64_t ArrayInitIndex = -1;
946
947	/// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
948	/// notes attached to it will also be stored, otherwise they will not be.
949	bool HasActiveDiagnostic;
950
951	/// Have we emitted a diagnostic explaining why we couldn't constant
952	/// fold (not just why it's not strictly a constant expression)?
953	bool HasFoldFailureDiagnostic;
954
955	/// Whether we're checking that an expression is a potential constant
956	/// expression. If so, do not fail on constructs that could become constant
957	/// later on (such as a use of an undefined global).
958	bool CheckingPotentialConstantExpression = false;
959
960	/// Whether we're checking for an expression that has undefined behavior.
961	/// If so, we will produce warnings if we encounter an operation that is
962	/// always undefined.
963	///
964	/// Note that we still need to evaluate the expression normally when this
965	/// is set; this is used when evaluating ICEs in C.
966	bool CheckingForUndefinedBehavior = false;
967
968	enum EvaluationMode {
969	/// Evaluate as a constant expression. Stop if we find that the expression
970	/// is not a constant expression.
971	EM_ConstantExpression,
972
973	/// Evaluate as a constant expression. Stop if we find that the expression
974	/// is not a constant expression. Some expressions can be retried in the
975	/// optimizer if we don't constant fold them here, but in an unevaluated
976	/// context we try to fold them immediately since the optimizer never
977	/// gets a chance to look at it.
978	EM_ConstantExpressionUnevaluated,
979
980	/// Fold the expression to a constant. Stop if we hit a side-effect that
981	/// we can't model.
982	EM_ConstantFold,
983
984	/// Evaluate in any way we know how. Don't worry about side-effects that
985	/// can't be modeled.
986	EM_IgnoreSideEffects,
987	} EvalMode;
988
989	/// Are we checking whether the expression is a potential constant
990	/// expression?
991	bool checkingPotentialConstantExpression() const override {
992	return CheckingPotentialConstantExpression;
993	}
994
995	/// Are we checking an expression for overflow?
996	// FIXME: We should check for any kind of undefined or suspicious behavior
997	// in such constructs, not just overflow.
998	bool checkingForUndefinedBehavior() const override {
999	return CheckingForUndefinedBehavior;
1000	}
1001
1002	EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
1003	: Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
1004	CallStackDepth(0), NextCallIndex(1),
1005	StepsLeft(C.getLangOpts().ConstexprStepLimit),
1006	EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
1007	BottomFrame(*this, SourceLocation(), /*Callee=*/nullptr,
1008	/*This=*/nullptr,
1009	/*CallExpr=*/nullptr, CallRef()),
1010	EvaluatingDecl((const ValueDecl *)nullptr),
1011	EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
1012	HasFoldFailureDiagnostic(false), EvalMode(Mode) {}
1013
1014	~EvalInfo() {
1015	discardCleanups();
1016	}
1017
1018	ASTContext &getCtx() const override { return Ctx; }
1019
1020	void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
1021	EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
1022	EvaluatingDecl = Base;
1023	IsEvaluatingDecl = EDK;
1024	EvaluatingDeclValue = &Value;
1025	}
1026
1027	bool CheckCallLimit(SourceLocation Loc) {
1028	// Don't perform any constexpr calls (other than the call we're checking)
1029	// when checking a potential constant expression.
1030	if (checkingPotentialConstantExpression() && CallStackDepth > 1)
1031	return false;
1032	if (NextCallIndex == 0) {
1033	// NextCallIndex has wrapped around.
1034	FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
1035	return false;
1036	}
1037	if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
1038	return true;
1039	FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
1040	<< getLangOpts().ConstexprCallDepth;
1041	return false;
1042	}
1043
1044	bool CheckArraySize(SourceLocation Loc, unsigned BitWidth,
1045	uint64_t ElemCount, bool Diag) {
1046	// FIXME: GH63562
1047	// APValue stores array extents as unsigned,
1048	// so anything that is greater that unsigned would overflow when
1049	// constructing the array, we catch this here.
1050	if (BitWidth > ConstantArrayType::getMaxSizeBits(Context: Ctx) ||
1051	ElemCount > uint64_t(std::numeric_limits<unsigned>::max())) {
1052	if (Diag)
1053	FFDiag(Loc, diag::note_constexpr_new_too_large) << ElemCount;
1054	return false;
1055	}
1056
1057	// FIXME: GH63562
1058	// Arrays allocate an APValue per element.
1059	// We use the number of constexpr steps as a proxy for the maximum size
1060	// of arrays to avoid exhausting the system resources, as initialization
1061	// of each element is likely to take some number of steps anyway.
1062	uint64_t Limit = Ctx.getLangOpts().ConstexprStepLimit;
1063	if (ElemCount > Limit) {
1064	if (Diag)
1065	FFDiag(Loc, diag::note_constexpr_new_exceeds_limits)
1066	<< ElemCount << Limit;
1067	return false;
1068	}
1069	return true;
1070	}
1071
1072	std::pair<CallStackFrame *, unsigned>
1073	getCallFrameAndDepth(unsigned CallIndex) {
1074	assert(CallIndex && "no call index in getCallFrameAndDepth");
1075	// We will eventually hit BottomFrame, which has Index 1, so Frame can't
1076	// be null in this loop.
1077	unsigned Depth = CallStackDepth;
1078	CallStackFrame *Frame = CurrentCall;
1079	while (Frame->Index > CallIndex) {
1080	Frame = Frame->Caller;
1081	--Depth;
1082	}
1083	if (Frame->Index == CallIndex)
1084	return {Frame, Depth};
1085	return {nullptr, 0};
1086	}
1087
1088	bool nextStep(const Stmt *S) {
1089	if (!StepsLeft) {
1090	FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded);
1091	return false;
1092	}
1093	--StepsLeft;
1094	return true;
1095	}
1096
1097	APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);
1098
1099	std::optional<DynAlloc *> lookupDynamicAlloc(DynamicAllocLValue DA) {
1100	std::optional<DynAlloc *> Result;
1101	auto It = HeapAllocs.find(x: DA);
1102	if (It != HeapAllocs.end())
1103	Result = &It->second;
1104	return Result;
1105	}
1106
1107	/// Get the allocated storage for the given parameter of the given call.
1108	APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) {
1109	CallStackFrame *Frame = getCallFrameAndDepth(CallIndex: Call.CallIndex).first;
1110	return Frame ? Frame->getTemporary(Key: Call.getOrigParam(PVD), Version: Call.Version)
1111	: nullptr;
1112	}
1113
1114	/// Information about a stack frame for std::allocator<T>::[de]allocate.
1115	struct StdAllocatorCaller {
1116	unsigned FrameIndex;
1117	QualType ElemType;
1118	explicit operator bool() const { return FrameIndex != 0; };
1119	};
1120
1121	StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
1122	for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
1123	Call = Call->Caller) {
1124	const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Val: Call->Callee);
1125	if (!MD)
1126	continue;
1127	const IdentifierInfo *FnII = MD->getIdentifier();
1128	if (!FnII || !FnII->isStr(Str: FnName))
1129	continue;
1130
1131	const auto *CTSD =
1132	dyn_cast<ClassTemplateSpecializationDecl>(Val: MD->getParent());
1133	if (!CTSD)
1134	continue;
1135
1136	const IdentifierInfo *ClassII = CTSD->getIdentifier();
1137	const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
1138	if (CTSD->isInStdNamespace() && ClassII &&
1139	ClassII->isStr(Str: "allocator") && TAL.size() >= 1 &&
1140	TAL[0].getKind() == TemplateArgument::Type)
1141	return {Call->Index, TAL[0].getAsType()};
1142	}
1143
1144	return {};
1145	}
1146
1147	void performLifetimeExtension() {
1148	// Disable the cleanups for lifetime-extended temporaries.
1149	llvm::erase_if(C&: CleanupStack, P: [](Cleanup &C) {
1150	return !C.isDestroyedAtEndOf(K: ScopeKind::FullExpression);
1151	});
1152	}
1153
1154	/// Throw away any remaining cleanups at the end of evaluation. If any
1155	/// cleanups would have had a side-effect, note that as an unmodeled
1156	/// side-effect and return false. Otherwise, return true.
1157	bool discardCleanups() {
1158	for (Cleanup &C : CleanupStack) {
1159	if (C.hasSideEffect() && !noteSideEffect()) {
1160	CleanupStack.clear();
1161	return false;
1162	}
1163	}
1164	CleanupStack.clear();
1165	return true;
1166	}
1167
1168	private:
1169	interp::Frame *getCurrentFrame() override { return CurrentCall; }
1170	const interp::Frame *getBottomFrame() const override { return &BottomFrame; }
1171
1172	bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
1173	void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }
1174
1175	void setFoldFailureDiagnostic(bool Flag) override {
1176	HasFoldFailureDiagnostic = Flag;
1177	}
1178
1179	Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }
1180
1181	// If we have a prior diagnostic, it will be noting that the expression
1182	// isn't a constant expression. This diagnostic is more important,
1183	// unless we require this evaluation to produce a constant expression.
1184	//
1185	// FIXME: We might want to show both diagnostics to the user in
1186	// EM_ConstantFold mode.
1187	bool hasPriorDiagnostic() override {
1188	if (!EvalStatus.Diag->empty()) {
1189	switch (EvalMode) {
1190	case EM_ConstantFold:
1191	case EM_IgnoreSideEffects:
1192	if (!HasFoldFailureDiagnostic)
1193	break;
1194	// We've already failed to fold something. Keep that diagnostic.
1195	[[fallthrough]];
1196	case EM_ConstantExpression:
1197	case EM_ConstantExpressionUnevaluated:
1198	setActiveDiagnostic(false);
1199	return true;
1200	}
1201	}
1202	return false;
1203	}
1204
1205	unsigned getCallStackDepth() override { return CallStackDepth; }
1206
1207	public:
1208	/// Should we continue evaluation after encountering a side-effect that we
1209	/// couldn't model?
1210	bool keepEvaluatingAfterSideEffect() {
1211	switch (EvalMode) {
1212	case EM_IgnoreSideEffects:
1213	return true;
1214
1215	case EM_ConstantExpression:
1216	case EM_ConstantExpressionUnevaluated:
1217	case EM_ConstantFold:
1218	// By default, assume any side effect might be valid in some other
1219	// evaluation of this expression from a different context.
1220	return checkingPotentialConstantExpression() ||
1221	checkingForUndefinedBehavior();
1222	}
1223	llvm_unreachable("Missed EvalMode case");
1224	}
1225
1226	/// Note that we have had a side-effect, and determine whether we should
1227	/// keep evaluating.
1228	bool noteSideEffect() {
1229	EvalStatus.HasSideEffects = true;
1230	return keepEvaluatingAfterSideEffect();
1231	}
1232
1233	/// Should we continue evaluation after encountering undefined behavior?
1234	bool keepEvaluatingAfterUndefinedBehavior() {
1235	switch (EvalMode) {
1236	case EM_IgnoreSideEffects:
1237	case EM_ConstantFold:
1238	return true;
1239
1240	case EM_ConstantExpression:
1241	case EM_ConstantExpressionUnevaluated:
1242	return checkingForUndefinedBehavior();
1243	}
1244	llvm_unreachable("Missed EvalMode case");
1245	}
1246
1247	/// Note that we hit something that was technically undefined behavior, but
1248	/// that we can evaluate past it (such as signed overflow or floating-point
1249	/// division by zero.)
1250	bool noteUndefinedBehavior() override {
1251	EvalStatus.HasUndefinedBehavior = true;
1252	return keepEvaluatingAfterUndefinedBehavior();
1253	}
1254
1255	/// Should we continue evaluation as much as possible after encountering a
1256	/// construct which can't be reduced to a value?
1257	bool keepEvaluatingAfterFailure() const override {
1258	if (!StepsLeft)
1259	return false;
1260
1261	switch (EvalMode) {
1262	case EM_ConstantExpression:
1263	case EM_ConstantExpressionUnevaluated:
1264	case EM_ConstantFold:
1265	case EM_IgnoreSideEffects:
1266	return checkingPotentialConstantExpression() ||
1267	checkingForUndefinedBehavior();
1268	}
1269	llvm_unreachable("Missed EvalMode case");
1270	}
1271
1272	/// Notes that we failed to evaluate an expression that other expressions
1273	/// directly depend on, and determine if we should keep evaluating. This
1274	/// should only be called if we actually intend to keep evaluating.
1275	///
1276	/// Call noteSideEffect() instead if we may be able to ignore the value that
1277	/// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
1278	///
1279	/// (Foo(), 1) // use noteSideEffect
1280	/// (Foo() || true) // use noteSideEffect
1281	/// Foo() + 1 // use noteFailure
1282	[[nodiscard]] bool noteFailure() {
1283	// Failure when evaluating some expression often means there is some
1284	// subexpression whose evaluation was skipped. Therefore, (because we
1285	// don't track whether we skipped an expression when unwinding after an
1286	// evaluation failure) every evaluation failure that bubbles up from a
1287	// subexpression implies that a side-effect has potentially happened. We
1288	// skip setting the HasSideEffects flag to true until we decide to
1289	// continue evaluating after that point, which happens here.
1290	bool KeepGoing = keepEvaluatingAfterFailure();
1291	EvalStatus.HasSideEffects |= KeepGoing;
1292	return KeepGoing;
1293	}
1294
1295	class ArrayInitLoopIndex {
1296	EvalInfo &Info;
1297	uint64_t OuterIndex;
1298
1299	public:
1300	ArrayInitLoopIndex(EvalInfo &Info)
1301	: Info(Info), OuterIndex(Info.ArrayInitIndex) {
1302	Info.ArrayInitIndex = 0;
1303	}
1304	~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
1305
1306	operator uint64_t&() { return Info.ArrayInitIndex; }
1307	};
1308	};
1309
1310	/// Object used to treat all foldable expressions as constant expressions.
1311	struct FoldConstant {
1312	EvalInfo &Info;
1313	bool Enabled;
1314	bool HadNoPriorDiags;
1315	EvalInfo::EvaluationMode OldMode;
1316
1317	explicit FoldConstant(EvalInfo &Info, bool Enabled)
1318	: Info(Info),
1319	Enabled(Enabled),
1320	HadNoPriorDiags(Info.EvalStatus.Diag &&
1321	Info.EvalStatus.Diag->empty() &&
1322	!Info.EvalStatus.HasSideEffects),
1323	OldMode(Info.EvalMode) {
1324	if (Enabled)
1325	Info.EvalMode = EvalInfo::EM_ConstantFold;
1326	}
1327	void keepDiagnostics() { Enabled = false; }
1328	~FoldConstant() {
1329	if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
1330	!Info.EvalStatus.HasSideEffects)
1331	Info.EvalStatus.Diag->clear();
1332	Info.EvalMode = OldMode;
1333	}
1334	};
1335
1336	/// RAII object used to set the current evaluation mode to ignore
1337	/// side-effects.
1338	struct IgnoreSideEffectsRAII {
1339	EvalInfo &Info;
1340	EvalInfo::EvaluationMode OldMode;
1341	explicit IgnoreSideEffectsRAII(EvalInfo &Info)
1342	: Info(Info), OldMode(Info.EvalMode) {
1343	Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
1344	}
1345
1346	~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
1347	};
1348
1349	/// RAII object used to optionally suppress diagnostics and side-effects from
1350	/// a speculative evaluation.
1351	class SpeculativeEvaluationRAII {
1352	EvalInfo *Info = nullptr;
1353	Expr::EvalStatus OldStatus;
1354	unsigned OldSpeculativeEvaluationDepth = 0;
1355
1356	void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
1357	Info = Other.Info;
1358	OldStatus = Other.OldStatus;
1359	OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
1360	Other.Info = nullptr;
1361	}
1362
1363	void maybeRestoreState() {
1364	if (!Info)
1365	return;
1366
1367	Info->EvalStatus = OldStatus;
1368	Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
1369	}
1370
1371	public:
1372	SpeculativeEvaluationRAII() = default;
1373
1374	SpeculativeEvaluationRAII(
1375	EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1376	: Info(&Info), OldStatus(Info.EvalStatus),
1377	OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
1378	Info.EvalStatus.Diag = NewDiag;
1379	Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
1380	}
1381
1382	SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1383	SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1384	moveFromAndCancel(Other: std::move(Other));
1385	}
1386
1387	SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1388	maybeRestoreState();
1389	moveFromAndCancel(Other: std::move(Other));
1390	return *this;
1391	}
1392
1393	~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1394	};
1395
1396	/// RAII object wrapping a full-expression or block scope, and handling
1397	/// the ending of the lifetime of temporaries created within it.
1398	template<ScopeKind Kind>
1399	class ScopeRAII {
1400	EvalInfo &Info;
1401	unsigned OldStackSize;
1402	public:
1403	ScopeRAII(EvalInfo &Info)
1404	: Info(Info), OldStackSize(Info.CleanupStack.size()) {
1405	// Push a new temporary version. This is needed to distinguish between
1406	// temporaries created in different iterations of a loop.
1407	Info.CurrentCall->pushTempVersion();
1408	}
1409	bool destroy(bool RunDestructors = true) {
1410	bool OK = cleanup(Info, RunDestructors, OldStackSize);
1411	OldStackSize = -1U;
1412	return OK;
1413	}
1414	~ScopeRAII() {
1415	if (OldStackSize != -1U)
1416	destroy(RunDestructors: false);
1417	// Body moved to a static method to encourage the compiler to inline away
1418	// instances of this class.
1419	Info.CurrentCall->popTempVersion();
1420	}
1421	private:
1422	static bool cleanup(EvalInfo &Info, bool RunDestructors,
1423	unsigned OldStackSize) {
1424	assert(OldStackSize <= Info.CleanupStack.size() &&
1425	"running cleanups out of order?");
1426
1427	// Run all cleanups for a block scope, and non-lifetime-extended cleanups
1428	// for a full-expression scope.
1429	bool Success = true;
1430	for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
1431	if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(K: Kind)) {
1432	if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
1433	Success = false;
1434	break;
1435	}
1436	}
1437	}
1438
1439	// Compact any retained cleanups.
1440	auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
1441	if (Kind != ScopeKind::Block)
1442	NewEnd =
1443	std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) {
1444	return C.isDestroyedAtEndOf(K: Kind);
1445	});
1446	Info.CleanupStack.erase(CS: NewEnd, CE: Info.CleanupStack.end());
1447	return Success;
1448	}
1449	};
1450	typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII;
1451	typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII;
1452	typedef ScopeRAII<ScopeKind::Call> CallScopeRAII;
1453	}
1454
1455	bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1456	CheckSubobjectKind CSK) {
1457	if (Invalid)
1458	return false;
1459	if (isOnePastTheEnd()) {
1460	Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1461	<< CSK;
1462	setInvalid();
1463	return false;
1464	}
1465	// Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
1466	// must actually be at least one array element; even a VLA cannot have a
1467	// bound of zero. And if our index is nonzero, we already had a CCEDiag.
1468	return true;
1469	}
1470
1471	void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
1472	const Expr *E) {
1473	Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed);
1474	// Do not set the designator as invalid: we can represent this situation,
1475	// and correct handling of __builtin_object_size requires us to do so.
1476	}
1477
1478	void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1479	const Expr *E,
1480	const APSInt &N) {
1481	// If we're complaining, we must be able to statically determine the size of
1482	// the most derived array.
1483	if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1484	Info.CCEDiag(E, diag::note_constexpr_array_index)
1485	<< N << /*array*/ 0
1486	<< static_cast<unsigned>(getMostDerivedArraySize());
1487	else
1488	Info.CCEDiag(E, diag::note_constexpr_array_index)
1489	<< N << /*non-array*/ 1;
1490	setInvalid();
1491	}
1492
1493	CallStackFrame::CallStackFrame(EvalInfo &Info, SourceRange CallRange,
1494	const FunctionDecl *Callee, const LValue *This,
1495	const Expr *CallExpr, CallRef Call)
1496	: Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1497	CallExpr(CallExpr), Arguments(Call), CallRange(CallRange),
1498	Index(Info.NextCallIndex++) {
1499	Info.CurrentCall = this;
1500	++Info.CallStackDepth;
1501	}
1502
1503	CallStackFrame::~CallStackFrame() {
1504	assert(Info.CurrentCall == this && "calls retired out of order");
1505	--Info.CallStackDepth;
1506	Info.CurrentCall = Caller;
1507	}
1508
1509	static bool isRead(AccessKinds AK) {
1510	return AK == AK_Read || AK == AK_ReadObjectRepresentation;
1511	}
1512
1513	static bool isModification(AccessKinds AK) {
1514	switch (AK) {
1515	case AK_Read:
1516	case AK_ReadObjectRepresentation:
1517	case AK_MemberCall:
1518	case AK_DynamicCast:
1519	case AK_TypeId:
1520	return false;
1521	case AK_Assign:
1522	case AK_Increment:
1523	case AK_Decrement:
1524	case AK_Construct:
1525	case AK_Destroy:
1526	return true;
1527	}
1528	llvm_unreachable("unknown access kind");
1529	}
1530
1531	static bool isAnyAccess(AccessKinds AK) {
1532	return isRead(AK) || isModification(AK);
1533	}
1534
1535	/// Is this an access per the C++ definition?
1536	static bool isFormalAccess(AccessKinds AK) {
1537	return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy;
1538	}
1539
1540	/// Is this kind of axcess valid on an indeterminate object value?
1541	static bool isValidIndeterminateAccess(AccessKinds AK) {
1542	switch (AK) {
1543	case AK_Read:
1544	case AK_Increment:
1545	case AK_Decrement:
1546	// These need the object's value.
1547	return false;
1548
1549	case AK_ReadObjectRepresentation:
1550	case AK_Assign:
1551	case AK_Construct:
1552	case AK_Destroy:
1553	// Construction and destruction don't need the value.
1554	return true;
1555
1556	case AK_MemberCall:
1557	case AK_DynamicCast:
1558	case AK_TypeId:
1559	// These aren't really meaningful on scalars.
1560	return true;
1561	}
1562	llvm_unreachable("unknown access kind");
1563	}
1564
1565	namespace {
1566	struct ComplexValue {
1567	private:
1568	bool IsInt;
1569
1570	public:
1571	APSInt IntReal, IntImag;
1572	APFloat FloatReal, FloatImag;
1573
1574	ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1575
1576	void makeComplexFloat() { IsInt = false; }
1577	bool isComplexFloat() const { return !IsInt; }
1578	APFloat &getComplexFloatReal() { return FloatReal; }
1579	APFloat &getComplexFloatImag() { return FloatImag; }
1580
1581	void makeComplexInt() { IsInt = true; }
1582	bool isComplexInt() const { return IsInt; }
1583	APSInt &getComplexIntReal() { return IntReal; }
1584	APSInt &getComplexIntImag() { return IntImag; }
1585
1586	void moveInto(APValue &v) const {
1587	if (isComplexFloat())
1588	v = APValue(FloatReal, FloatImag);
1589	else
1590	v = APValue(IntReal, IntImag);
1591	}
1592	void setFrom(const APValue &v) {
1593	assert(v.isComplexFloat() || v.isComplexInt());
1594	if (v.isComplexFloat()) {
1595	makeComplexFloat();
1596	FloatReal = v.getComplexFloatReal();
1597	FloatImag = v.getComplexFloatImag();
1598	} else {
1599	makeComplexInt();
1600	IntReal = v.getComplexIntReal();
1601	IntImag = v.getComplexIntImag();
1602	}
1603	}
1604	};
1605
1606	struct LValue {
1607	APValue::LValueBase Base;
1608	CharUnits Offset;
1609	SubobjectDesignator Designator;
1610	bool IsNullPtr : 1;
1611	bool InvalidBase : 1;
1612
1613	const APValue::LValueBase getLValueBase() const { return Base; }
1614	CharUnits &getLValueOffset() { return Offset; }
1615	const CharUnits &getLValueOffset() const { return Offset; }
1616	SubobjectDesignator &getLValueDesignator() { return Designator; }
1617	const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1618	bool isNullPointer() const { return IsNullPtr;}
1619
1620	unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
1621	unsigned getLValueVersion() const { return Base.getVersion(); }
1622
1623	void moveInto(APValue &V) const {
1624	if (Designator.Invalid)
1625	V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
1626	else {
1627	assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1628	V = APValue(Base, Offset, Designator.Entries,
1629	Designator.IsOnePastTheEnd, IsNullPtr);
1630	}
1631	}
1632	void setFrom(ASTContext &Ctx, const APValue &V) {
1633	assert(V.isLValue() && "Setting LValue from a non-LValue?");
1634	Base = V.getLValueBase();
1635	Offset = V.getLValueOffset();
1636	InvalidBase = false;
1637	Designator = SubobjectDesignator(Ctx, V);
1638	IsNullPtr = V.isNullPointer();
1639	}
1640
1641	void set(APValue::LValueBase B, bool BInvalid = false) {
1642	#ifndef NDEBUG
1643	// We only allow a few types of invalid bases. Enforce that here.
1644	if (BInvalid) {
1645	const auto *E = B.get<const Expr *>();
1646	assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1647	"Unexpected type of invalid base");
1648	}
1649	#endif
1650
1651	Base = B;
1652	Offset = CharUnits::fromQuantity(Quantity: 0);
1653	InvalidBase = BInvalid;
1654	Designator = SubobjectDesignator(getType(B));
1655	IsNullPtr = false;
1656	}
1657
1658	void setNull(ASTContext &Ctx, QualType PointerTy) {
1659	Base = (const ValueDecl *)nullptr;
1660	Offset =
1661	CharUnits::fromQuantity(Quantity: Ctx.getTargetNullPointerValue(QT: PointerTy));
1662	InvalidBase = false;
1663	Designator = SubobjectDesignator(PointerTy->getPointeeType());
1664	IsNullPtr = true;
1665	}
1666
1667	void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1668	set(B, BInvalid: true);
1669	}
1670
1671	std::string toString(ASTContext &Ctx, QualType T) const {
1672	APValue Printable;
1673	moveInto(V&: Printable);
1674	return Printable.getAsString(Ctx, Ty: T);
1675	}
1676
1677	private:
1678	// Check that this LValue is not based on a null pointer. If it is, produce
1679	// a diagnostic and mark the designator as invalid.
1680	template <typename GenDiagType>
1681	bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
1682	if (Designator.Invalid)
1683	return false;
1684	if (IsNullPtr) {
1685	GenDiag();
1686	Designator.setInvalid();
1687	return false;
1688	}
1689	return true;
1690	}
1691
1692	public:
1693	bool checkNullPointer(EvalInfo &Info, const Expr *E,
1694	CheckSubobjectKind CSK) {
1695	return checkNullPointerDiagnosingWith(GenDiag: [&Info, E, CSK] {
1696	Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK;
1697	});
1698	}
1699
1700	bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
1701	AccessKinds AK) {
1702	return checkNullPointerDiagnosingWith(GenDiag: [&Info, E, AK] {
1703	Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
1704	});
1705	}
1706
1707	// Check this LValue refers to an object. If not, set the designator to be
1708	// invalid and emit a diagnostic.
1709	bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1710	return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1711	Designator.checkSubobject(Info, E, CSK);
1712	}
1713
1714	void addDecl(EvalInfo &Info, const Expr *E,
1715	const Decl *D, bool Virtual = false) {
1716	if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1717	Designator.addDeclUnchecked(D, Virtual);
1718	}
1719	void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
1720	if (!Designator.Entries.empty()) {
1721	Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array);
1722	Designator.setInvalid();
1723	return;
1724	}
1725	if (checkSubobject(Info, E, CSK: CSK_ArrayToPointer)) {
1726	assert(getType(Base)->isPointerType() || getType(Base)->isArrayType());
1727	Designator.FirstEntryIsAnUnsizedArray = true;
1728	Designator.addUnsizedArrayUnchecked(ElemTy);
1729	}
1730	}
1731	void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1732	if (checkSubobject(Info, E, CSK_ArrayToPointer))
1733	Designator.addArrayUnchecked(CAT);
1734	}
1735	void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1736	if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1737	Designator.addComplexUnchecked(EltTy, Imag);
1738	}
1739	void clearIsNullPointer() {
1740	IsNullPtr = false;
1741	}
1742	void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1743	const APSInt &Index, CharUnits ElementSize) {
1744	// An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1745	// but we're not required to diagnose it and it's valid in C++.)
1746	if (!Index)
1747	return;
1748
1749	// Compute the new offset in the appropriate width, wrapping at 64 bits.
1750	// FIXME: When compiling for a 32-bit target, we should use 32-bit
1751	// offsets.
1752	uint64_t Offset64 = Offset.getQuantity();
1753	uint64_t ElemSize64 = ElementSize.getQuantity();
1754	uint64_t Index64 = Index.extOrTrunc(width: 64).getZExtValue();
1755	Offset = CharUnits::fromQuantity(Quantity: Offset64 + ElemSize64 * Index64);
1756
1757	if (checkNullPointer(Info, E, CSK_ArrayIndex))
1758	Designator.adjustIndex(Info, E, Index);
1759	clearIsNullPointer();
1760	}
1761	void adjustOffset(CharUnits N) {
1762	Offset += N;
1763	if (N.getQuantity())
1764	clearIsNullPointer();
1765	}
1766	};
1767
1768	struct MemberPtr {
1769	MemberPtr() {}
1770	explicit MemberPtr(const ValueDecl *Decl)
1771	: DeclAndIsDerivedMember(Decl, false) {}
1772
1773	/// The member or (direct or indirect) field referred to by this member
1774	/// pointer, or 0 if this is a null member pointer.
1775	const ValueDecl *getDecl() const {
1776	return DeclAndIsDerivedMember.getPointer();
1777	}
1778	/// Is this actually a member of some type derived from the relevant class?
1779	bool isDerivedMember() const {
1780	return DeclAndIsDerivedMember.getInt();
1781	}
1782	/// Get the class which the declaration actually lives in.
1783	const CXXRecordDecl *getContainingRecord() const {
1784	return cast<CXXRecordDecl>(
1785	DeclAndIsDerivedMember.getPointer()->getDeclContext());
1786	}
1787
1788	void moveInto(APValue &V) const {
1789	V = APValue(getDecl(), isDerivedMember(), Path);
1790	}
1791	void setFrom(const APValue &V) {
1792	assert(V.isMemberPointer());
1793	DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1794	DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1795	Path.clear();
1796	ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1797	Path.insert(I: Path.end(), From: P.begin(), To: P.end());
1798	}
1799
1800	/// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1801	/// whether the member is a member of some class derived from the class type
1802	/// of the member pointer.
1803	llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1804	/// Path - The path of base/derived classes from the member declaration's
1805	/// class (exclusive) to the class type of the member pointer (inclusive).
1806	SmallVector<const CXXRecordDecl*, 4> Path;
1807
1808	/// Perform a cast towards the class of the Decl (either up or down the
1809	/// hierarchy).
1810	bool castBack(const CXXRecordDecl *Class) {
1811	assert(!Path.empty());
1812	const CXXRecordDecl *Expected;
1813	if (Path.size() >= 2)
1814	Expected = Path[Path.size() - 2];
1815	else
1816	Expected = getContainingRecord();
1817	if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1818	// C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1819	// if B does not contain the original member and is not a base or
1820	// derived class of the class containing the original member, the result
1821	// of the cast is undefined.
1822	// C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1823	// (D::*). We consider that to be a language defect.
1824	return false;
1825	}
1826	Path.pop_back();
1827	return true;
1828	}
1829	/// Perform a base-to-derived member pointer cast.
1830	bool castToDerived(const CXXRecordDecl *Derived) {
1831	if (!getDecl())
1832	return true;
1833	if (!isDerivedMember()) {
1834	Path.push_back(Elt: Derived);
1835	return true;
1836	}
1837	if (!castBack(Class: Derived))
1838	return false;
1839	if (Path.empty())
1840	DeclAndIsDerivedMember.setInt(false);
1841	return true;
1842	}
1843	/// Perform a derived-to-base member pointer cast.
1844	bool castToBase(const CXXRecordDecl *Base) {
1845	if (!getDecl())
1846	return true;
1847	if (Path.empty())
1848	DeclAndIsDerivedMember.setInt(true);
1849	if (isDerivedMember()) {
1850	Path.push_back(Elt: Base);
1851	return true;
1852	}
1853	return castBack(Class: Base);
1854	}
1855	};
1856
1857	/// Compare two member pointers, which are assumed to be of the same type.
1858	static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1859	if (!LHS.getDecl() || !RHS.getDecl())
1860	return !LHS.getDecl() && !RHS.getDecl();
1861	if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1862	return false;
1863	return LHS.Path == RHS.Path;
1864	}
1865	}
1866
1867	static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1868	static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1869	const LValue &This, const Expr *E,
1870	bool AllowNonLiteralTypes = false);
1871	static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1872	bool InvalidBaseOK = false);
1873	static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1874	bool InvalidBaseOK = false);
1875	static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1876	EvalInfo &Info);
1877	static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1878	static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1879	static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1880	EvalInfo &Info);
1881	static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1882	static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1883	static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1884	EvalInfo &Info);
1885	static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1886	static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result,
1887	EvalInfo &Info);
1888
1889	/// Evaluate an integer or fixed point expression into an APResult.
1890	static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
1891	EvalInfo &Info);
1892
1893	/// Evaluate only a fixed point expression into an APResult.
1894	static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
1895	EvalInfo &Info);
1896
1897	//===----------------------------------------------------------------------===//
1898	// Misc utilities
1899	//===----------------------------------------------------------------------===//
1900
1901	/// Negate an APSInt in place, converting it to a signed form if necessary, and
1902	/// preserving its value (by extending by up to one bit as needed).
1903	static void negateAsSigned(APSInt &Int) {
1904	if (Int.isUnsigned() || Int.isMinSignedValue()) {
1905	Int = Int.extend(width: Int.getBitWidth() + 1);
1906	Int.setIsSigned(true);
1907	}
1908	Int = -Int;
1909	}
1910
1911	template<typename KeyT>
1912	APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
1913	ScopeKind Scope, LValue &LV) {
1914	unsigned Version = getTempVersion();
1915	APValue::LValueBase Base(Key, Index, Version);
1916	LV.set(B: Base);
1917	return createLocal(Base, Key, T, Scope);
1918	}
1919
1920	/// Allocate storage for a parameter of a function call made in this frame.
1921	APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
1922	LValue &LV) {
1923	assert(Args.CallIndex == Index && "creating parameter in wrong frame");
1924	APValue::LValueBase Base(PVD, Index, Args.Version);
1925	LV.set(B: Base);
1926	// We always destroy parameters at the end of the call, even if we'd allow
1927	// them to live to the end of the full-expression at runtime, in order to
1928	// give portable results and match other compilers.
1929	return createLocal(Base, Key: PVD, T: PVD->getType(), Scope: ScopeKind::Call);
1930	}
1931
1932	APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key,
1933	QualType T, ScopeKind Scope) {
1934	assert(Base.getCallIndex() == Index && "lvalue for wrong frame");
1935	unsigned Version = Base.getVersion();
1936	APValue &Result = Temporaries[MapKeyTy(Key, Version)];
1937	assert(Result.isAbsent() && "local created multiple times");
1938
1939	// If we're creating a local immediately in the operand of a speculative
1940	// evaluation, don't register a cleanup to be run outside the speculative
1941	// evaluation context, since we won't actually be able to initialize this
1942	// object.
1943	if (Index <= Info.SpeculativeEvaluationDepth) {
1944	if (T.isDestructedType())
1945	Info.noteSideEffect();
1946	} else {
1947	Info.CleanupStack.push_back(Elt: Cleanup(&Result, Base, T, Scope));
1948	}
1949	return Result;
1950	}
1951
1952	APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
1953	if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
1954	FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded);
1955	return nullptr;
1956	}
1957
1958	DynamicAllocLValue DA(NumHeapAllocs++);
1959	LV.set(B: APValue::LValueBase::getDynamicAlloc(LV: DA, Type: T));
1960	auto Result = HeapAllocs.emplace(args: std::piecewise_construct,
1961	args: std::forward_as_tuple(args&: DA), args: std::tuple<>());
1962	assert(Result.second && "reused a heap alloc index?");
1963	Result.first->second.AllocExpr = E;
1964	return &Result.first->second.Value;
1965	}
1966
1967	/// Produce a string describing the given constexpr call.
1968	void CallStackFrame::describe(raw_ostream &Out) const {
1969	unsigned ArgIndex = 0;
1970	bool IsMemberCall =
1971	isa<CXXMethodDecl>(Val: Callee) && !isa<CXXConstructorDecl>(Val: Callee) &&
1972	cast<CXXMethodDecl>(Val: Callee)->isImplicitObjectMemberFunction();
1973
1974	if (!IsMemberCall)
1975	Callee->getNameForDiagnostic(OS&: Out, Policy: Info.Ctx.getPrintingPolicy(),
1976	/*Qualified=*/false);
1977
1978	if (This && IsMemberCall) {
1979	if (const auto *MCE = dyn_cast_if_present<CXXMemberCallExpr>(Val: CallExpr)) {
1980	const Expr *Object = MCE->getImplicitObjectArgument();
1981	Object->printPretty(Out, /*Helper=*/nullptr, Info.Ctx.getPrintingPolicy(),
1982	/*Indentation=*/0);
1983	if (Object->getType()->isPointerType())
1984	Out << "->";
1985	else
1986	Out << ".";
1987	} else if (const auto *OCE =
1988	dyn_cast_if_present<CXXOperatorCallExpr>(Val: CallExpr)) {
1989	OCE->getArg(0)->printPretty(Out, /*Helper=*/nullptr,
1990	Info.Ctx.getPrintingPolicy(),
1991	/*Indentation=*/0);
1992	Out << ".";
1993	} else {
1994	APValue Val;
1995	This->moveInto(V&: Val);
1996	Val.printPretty(
1997	Out, Info.Ctx,
1998	Info.Ctx.getLValueReferenceType(T: This->Designator.MostDerivedType));
1999	Out << ".";
2000	}
2001	Callee->getNameForDiagnostic(OS&: Out, Policy: Info.Ctx.getPrintingPolicy(),
2002	/*Qualified=*/false);
2003	IsMemberCall = false;
2004	}
2005
2006	Out << '(';
2007
2008	for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
2009	E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
2010	if (ArgIndex > (unsigned)IsMemberCall)
2011	Out << ", ";
2012
2013	const ParmVarDecl *Param = *I;
2014	APValue *V = Info.getParamSlot(Call: Arguments, PVD: Param);
2015	if (V)
2016	V->printPretty(Out, Info.Ctx, Param->getType());
2017	else
2018	Out << "<...>";
2019
2020	if (ArgIndex == 0 && IsMemberCall)
2021	Out << "->" << *Callee << '(';
2022	}
2023
2024	Out << ')';
2025	}
2026
2027	/// Evaluate an expression to see if it had side-effects, and discard its
2028	/// result.
2029	/// \return \c true if the caller should keep evaluating.
2030	static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
2031	assert(!E->isValueDependent());
2032	APValue Scratch;
2033	if (!Evaluate(Result&: Scratch, Info, E))
2034	// We don't need the value, but we might have skipped a side effect here.
2035	return Info.noteSideEffect();
2036	return true;
2037	}
2038
2039	/// Should this call expression be treated as a no-op?
2040	static bool IsNoOpCall(const CallExpr *E) {
2041	unsigned Builtin = E->getBuiltinCallee();
2042	return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
2043	Builtin == Builtin::BI__builtin___NSStringMakeConstantString ||
2044	Builtin == Builtin::BI__builtin_function_start);
2045	}
2046
2047	static bool IsGlobalLValue(APValue::LValueBase B) {
2048	// C++11 [expr.const]p3 An address constant expression is a prvalue core
2049	// constant expression of pointer type that evaluates to...
2050
2051	// ... a null pointer value, or a prvalue core constant expression of type
2052	// std::nullptr_t.
2053	if (!B)
2054	return true;
2055
2056	if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
2057	// ... the address of an object with static storage duration,
2058	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
2059	return VD->hasGlobalStorage();
2060	if (isa<TemplateParamObjectDecl>(Val: D))
2061	return true;
2062	// ... the address of a function,
2063	// ... the address of a GUID [MS extension],
2064	// ... the address of an unnamed global constant
2065	return isa<FunctionDecl, MSGuidDecl, UnnamedGlobalConstantDecl>(Val: D);
2066	}
2067
2068	if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
2069	return true;
2070
2071	const Expr *E = B.get<const Expr*>();
2072	switch (E->getStmtClass()) {
2073	default:
2074	return false;
2075	case Expr::CompoundLiteralExprClass: {
2076	const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(Val: E);
2077	return CLE->isFileScope() && CLE->isLValue();
2078	}
2079	case Expr::MaterializeTemporaryExprClass:
2080	// A materialized temporary might have been lifetime-extended to static
2081	// storage duration.
2082	return cast<MaterializeTemporaryExpr>(Val: E)->getStorageDuration() == SD_Static;
2083	// A string literal has static storage duration.
2084	case Expr::StringLiteralClass:
2085	case Expr::PredefinedExprClass:
2086	case Expr::ObjCStringLiteralClass:
2087	case Expr::ObjCEncodeExprClass:
2088	return true;
2089	case Expr::ObjCBoxedExprClass:
2090	return cast<ObjCBoxedExpr>(Val: E)->isExpressibleAsConstantInitializer();
2091	case Expr::CallExprClass:
2092	return IsNoOpCall(E: cast<CallExpr>(Val: E));
2093	// For GCC compatibility, &&label has static storage duration.
2094	case Expr::AddrLabelExprClass:
2095	return true;
2096	// A Block literal expression may be used as the initialization value for
2097	// Block variables at global or local static scope.
2098	case Expr::BlockExprClass:
2099	return !cast<BlockExpr>(Val: E)->getBlockDecl()->hasCaptures();
2100	// The APValue generated from a __builtin_source_location will be emitted as a
2101	// literal.
2102	case Expr::SourceLocExprClass:
2103	return true;
2104	case Expr::ImplicitValueInitExprClass:
2105	// FIXME:
2106	// We can never form an lvalue with an implicit value initialization as its
2107	// base through expression evaluation, so these only appear in one case: the
2108	// implicit variable declaration we invent when checking whether a constexpr
2109	// constructor can produce a constant expression. We must assume that such
2110	// an expression might be a global lvalue.
2111	return true;
2112	}
2113	}
2114
2115	static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
2116	return LVal.Base.dyn_cast<const ValueDecl*>();
2117	}
2118
2119	static bool IsLiteralLValue(const LValue &Value) {
2120	if (Value.getLValueCallIndex())
2121	return false;
2122	const Expr *E = Value.Base.dyn_cast<const Expr*>();
2123	return E && !isa<MaterializeTemporaryExpr>(Val: E);
2124	}
2125
2126	static bool IsWeakLValue(const LValue &Value) {
2127	const ValueDecl *Decl = GetLValueBaseDecl(LVal: Value);
2128	return Decl && Decl->isWeak();
2129	}
2130
2131	static bool isZeroSized(const LValue &Value) {
2132	const ValueDecl *Decl = GetLValueBaseDecl(LVal: Value);
2133	if (Decl && isa<VarDecl>(Val: Decl)) {
2134	QualType Ty = Decl->getType();
2135	if (Ty->isArrayType())
2136	return Ty->isIncompleteType() ||
2137	Decl->getASTContext().getTypeSize(Ty) == 0;
2138	}
2139	return false;
2140	}
2141
2142	static bool HasSameBase(const LValue &A, const LValue &B) {
2143	if (!A.getLValueBase())
2144	return !B.getLValueBase();
2145	if (!B.getLValueBase())
2146	return false;
2147
2148	if (A.getLValueBase().getOpaqueValue() !=
2149	B.getLValueBase().getOpaqueValue())
2150	return false;
2151
2152	return A.getLValueCallIndex() == B.getLValueCallIndex() &&
2153	A.getLValueVersion() == B.getLValueVersion();
2154	}
2155
2156	static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
2157	assert(Base && "no location for a null lvalue");
2158	const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2159
2160	// For a parameter, find the corresponding call stack frame (if it still
2161	// exists), and point at the parameter of the function definition we actually
2162	// invoked.
2163	if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(Val: VD)) {
2164	unsigned Idx = PVD->getFunctionScopeIndex();
2165	for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) {
2166	if (F->Arguments.CallIndex == Base.getCallIndex() &&
2167	F->Arguments.Version == Base.getVersion() && F->Callee &&
2168	Idx < F->Callee->getNumParams()) {
2169	VD = F->Callee->getParamDecl(i: Idx);
2170	break;
2171	}
2172	}
2173	}
2174
2175	if (VD)
2176	Info.Note(VD->getLocation(), diag::note_declared_at);
2177	else if (const Expr *E = Base.dyn_cast<const Expr*>())
2178	Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
2179	else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
2180	// FIXME: Produce a note for dangling pointers too.
2181	if (std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA))
2182	Info.Note((*Alloc)->AllocExpr->getExprLoc(),
2183	diag::note_constexpr_dynamic_alloc_here);
2184	}
2185
2186	// We have no information to show for a typeid(T) object.
2187	}
2188
2189	enum class CheckEvaluationResultKind {
2190	ConstantExpression,
2191	FullyInitialized,
2192	};
2193
2194	/// Materialized temporaries that we've already checked to determine if they're
2195	/// initializsed by a constant expression.
2196	using CheckedTemporaries =
2197	llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;
2198
2199	static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2200	EvalInfo &Info, SourceLocation DiagLoc,
2201	QualType Type, const APValue &Value,
2202	ConstantExprKind Kind,
2203	const FieldDecl *SubobjectDecl,
2204	CheckedTemporaries &CheckedTemps);
2205
2206	/// Check that this reference or pointer core constant expression is a valid
2207	/// value for an address or reference constant expression. Return true if we
2208	/// can fold this expression, whether or not it's a constant expression.
2209	static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
2210	QualType Type, const LValue &LVal,
2211	ConstantExprKind Kind,
2212	CheckedTemporaries &CheckedTemps) {
2213	bool IsReferenceType = Type->isReferenceType();
2214
2215	APValue::LValueBase Base = LVal.getLValueBase();
2216	const SubobjectDesignator &Designator = LVal.getLValueDesignator();
2217
2218	const Expr *BaseE = Base.dyn_cast<const Expr *>();
2219	const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>();
2220
2221	// Additional restrictions apply in a template argument. We only enforce the
2222	// C++20 restrictions here; additional syntactic and semantic restrictions
2223	// are applied elsewhere.
2224	if (isTemplateArgument(Kind)) {
2225	int InvalidBaseKind = -1;
2226	StringRef Ident;
2227	if (Base.is<TypeInfoLValue>())
2228	InvalidBaseKind = 0;
2229	else if (isa_and_nonnull<StringLiteral>(Val: BaseE))
2230	InvalidBaseKind = 1;
2231	else if (isa_and_nonnull<MaterializeTemporaryExpr>(Val: BaseE) ||
2232	isa_and_nonnull<LifetimeExtendedTemporaryDecl>(Val: BaseVD))
2233	InvalidBaseKind = 2;
2234	else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(Val: BaseE)) {
2235	InvalidBaseKind = 3;
2236	Ident = PE->getIdentKindName();
2237	}
2238
2239	if (InvalidBaseKind != -1) {
2240	Info.FFDiag(Loc, diag::note_constexpr_invalid_template_arg)
2241	<< IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind
2242	<< Ident;
2243	return false;
2244	}
2245	}
2246
2247	if (auto *FD = dyn_cast_or_null<FunctionDecl>(Val: BaseVD);
2248	FD && FD->isImmediateFunction()) {
2249	Info.FFDiag(Loc, diag::note_consteval_address_accessible)
2250	<< !Type->isAnyPointerType();
2251	Info.Note(FD->getLocation(), diag::note_declared_at);
2252	return false;
2253	}
2254
2255	// Check that the object is a global. Note that the fake 'this' object we
2256	// manufacture when checking potential constant expressions is conservatively
2257	// assumed to be global here.
2258	if (!IsGlobalLValue(B: Base)) {
2259	if (Info.getLangOpts().CPlusPlus11) {
2260	Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
2261	<< IsReferenceType << !Designator.Entries.empty() << !!BaseVD
2262	<< BaseVD;
2263	auto *VarD = dyn_cast_or_null<VarDecl>(Val: BaseVD);
2264	if (VarD && VarD->isConstexpr()) {
2265	// Non-static local constexpr variables have unintuitive semantics:
2266	// constexpr int a = 1;
2267	// constexpr const int *p = &a;
2268	// ... is invalid because the address of 'a' is not constant. Suggest
2269	// adding a 'static' in this case.
2270	Info.Note(VarD->getLocation(), diag::note_constexpr_not_static)
2271	<< VarD
2272	<< FixItHint::CreateInsertion(VarD->getBeginLoc(), "static ");
2273	} else {
2274	NoteLValueLocation(Info, Base);
2275	}
2276	} else {
2277	Info.FFDiag(Loc);
2278	}
2279	// Don't allow references to temporaries to escape.
2280	return false;
2281	}
2282	assert((Info.checkingPotentialConstantExpression() ||
2283	LVal.getLValueCallIndex() == 0) &&
2284	"have call index for global lvalue");
2285
2286	if (Base.is<DynamicAllocLValue>()) {
2287	Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc)
2288	<< IsReferenceType << !Designator.Entries.empty();
2289	NoteLValueLocation(Info, Base);
2290	return false;
2291	}
2292
2293	if (BaseVD) {
2294	if (const VarDecl *Var = dyn_cast<const VarDecl>(Val: BaseVD)) {
2295	// Check if this is a thread-local variable.
2296	if (Var->getTLSKind())
2297	// FIXME: Diagnostic!
2298	return false;
2299
2300	// A dllimport variable never acts like a constant, unless we're
2301	// evaluating a value for use only in name mangling.
2302	if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>())
2303	// FIXME: Diagnostic!
2304	return false;
2305
2306	// In CUDA/HIP device compilation, only device side variables have
2307	// constant addresses.
2308	if (Info.getCtx().getLangOpts().CUDA &&
2309	Info.getCtx().getLangOpts().CUDAIsDevice &&
2310	Info.getCtx().CUDAConstantEvalCtx.NoWrongSidedVars) {
2311	if ((!Var->hasAttr<CUDADeviceAttr>() &&
2312	!Var->hasAttr<CUDAConstantAttr>() &&
2313	!Var->getType()->isCUDADeviceBuiltinSurfaceType() &&
2314	!Var->getType()->isCUDADeviceBuiltinTextureType()) ||
2315	Var->hasAttr<HIPManagedAttr>())
2316	return false;
2317	}
2318	}
2319	if (const auto *FD = dyn_cast<const FunctionDecl>(Val: BaseVD)) {
2320	// __declspec(dllimport) must be handled very carefully:
2321	// We must never initialize an expression with the thunk in C++.
2322	// Doing otherwise would allow the same id-expression to yield
2323	// different addresses for the same function in different translation
2324	// units. However, this means that we must dynamically initialize the
2325	// expression with the contents of the import address table at runtime.
2326	//
2327	// The C language has no notion of ODR; furthermore, it has no notion of
2328	// dynamic initialization. This means that we are permitted to
2329	// perform initialization with the address of the thunk.
2330	if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) &&
2331	FD->hasAttr<DLLImportAttr>())
2332	// FIXME: Diagnostic!
2333	return false;
2334	}
2335	} else if (const auto *MTE =
2336	dyn_cast_or_null<MaterializeTemporaryExpr>(Val: BaseE)) {
2337	if (CheckedTemps.insert(Ptr: MTE).second) {
2338	QualType TempType = getType(B: Base);
2339	if (TempType.isDestructedType()) {
2340	Info.FFDiag(MTE->getExprLoc(),
2341	diag::note_constexpr_unsupported_temporary_nontrivial_dtor)
2342	<< TempType;
2343	return false;
2344	}
2345
2346	APValue *V = MTE->getOrCreateValue(MayCreate: false);
2347	assert(V && "evasluation result refers to uninitialised temporary");
2348	if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2349	Info, MTE->getExprLoc(), TempType, *V, Kind,
2350	/*SubobjectDecl=*/nullptr, CheckedTemps))
2351	return false;
2352	}
2353	}
2354
2355	// Allow address constant expressions to be past-the-end pointers. This is
2356	// an extension: the standard requires them to point to an object.
2357	if (!IsReferenceType)
2358	return true;
2359
2360	// A reference constant expression must refer to an object.
2361	if (!Base) {
2362	// FIXME: diagnostic
2363	Info.CCEDiag(Loc);
2364	return true;
2365	}
2366
2367	// Does this refer one past the end of some object?
2368	if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
2369	Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
2370	<< !Designator.Entries.empty() << !!BaseVD << BaseVD;
2371	NoteLValueLocation(Info, Base);
2372	}
2373
2374	return true;
2375	}
2376
2377	/// Member pointers are constant expressions unless they point to a
2378	/// non-virtual dllimport member function.
2379	static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
2380	SourceLocation Loc,
2381	QualType Type,
2382	const APValue &Value,
2383	ConstantExprKind Kind) {
2384	const ValueDecl *Member = Value.getMemberPointerDecl();
2385	const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Val: Member);
2386	if (!FD)
2387	return true;
2388	if (FD->isImmediateFunction()) {
2389	Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0;
2390	Info.Note(FD->getLocation(), diag::note_declared_at);
2391	return false;
2392	}
2393	return isForManglingOnly(Kind) || FD->isVirtual() ||
2394	!FD->hasAttr<DLLImportAttr>();
2395	}
2396
2397	/// Check that this core constant expression is of literal type, and if not,
2398	/// produce an appropriate diagnostic.
2399	static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
2400	const LValue *This = nullptr) {
2401	if (!E->isPRValue() || E->getType()->isLiteralType(Ctx: Info.Ctx))
2402	return true;
2403
2404	// C++1y: A constant initializer for an object o [...] may also invoke
2405	// constexpr constructors for o and its subobjects even if those objects
2406	// are of non-literal class types.
2407	//
2408	// C++11 missed this detail for aggregates, so classes like this:
2409	// struct foo_t { union { int i; volatile int j; } u; };
2410	// are not (obviously) initializable like so:
2411	// __attribute__((__require_constant_initialization__))
2412	// static const foo_t x = {{0}};
2413	// because "i" is a subobject with non-literal initialization (due to the
2414	// volatile member of the union). See:
2415	// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
2416	// Therefore, we use the C++1y behavior.
2417	if (This && Info.EvaluatingDecl == This->getLValueBase())
2418	return true;
2419
2420	// Prvalue constant expressions must be of literal types.
2421	if (Info.getLangOpts().CPlusPlus11)
2422	Info.FFDiag(E, diag::note_constexpr_nonliteral)
2423	<< E->getType();
2424	else
2425	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2426	return false;
2427	}
2428
2429	static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2430	EvalInfo &Info, SourceLocation DiagLoc,
2431	QualType Type, const APValue &Value,
2432	ConstantExprKind Kind,
2433	const FieldDecl *SubobjectDecl,
2434	CheckedTemporaries &CheckedTemps) {
2435	if (!Value.hasValue()) {
2436	if (SubobjectDecl) {
2437	Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
2438	<< /*(name)*/ 1 << SubobjectDecl;
2439	Info.Note(SubobjectDecl->getLocation(),
2440	diag::note_constexpr_subobject_declared_here);
2441	} else {
2442	Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
2443	<< /*of type*/ 0 << Type;
2444	}
2445	return false;
2446	}
2447
2448	// We allow _Atomic(T) to be initialized from anything that T can be
2449	// initialized from.
2450	if (const AtomicType *AT = Type->getAs<AtomicType>())
2451	Type = AT->getValueType();
2452
2453	// Core issue 1454: For a literal constant expression of array or class type,
2454	// each subobject of its value shall have been initialized by a constant
2455	// expression.
2456	if (Value.isArray()) {
2457	QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
2458	for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
2459	if (!CheckEvaluationResult(CERK, Info, DiagLoc, Type: EltTy,
2460	Value: Value.getArrayInitializedElt(I), Kind,
2461	SubobjectDecl, CheckedTemps))
2462	return false;
2463	}
2464	if (!Value.hasArrayFiller())
2465	return true;
2466	return CheckEvaluationResult(CERK, Info, DiagLoc, Type: EltTy,
2467	Value: Value.getArrayFiller(), Kind, SubobjectDecl,
2468	CheckedTemps);
2469	}
2470	if (Value.isUnion() && Value.getUnionField()) {
2471	return CheckEvaluationResult(
2472	CERK, Info, DiagLoc, Value.getUnionField()->getType(),
2473	Value.getUnionValue(), Kind, Value.getUnionField(), CheckedTemps);
2474	}
2475	if (Value.isStruct()) {
2476	RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
2477	if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(Val: RD)) {
2478	unsigned BaseIndex = 0;
2479	for (const CXXBaseSpecifier &BS : CD->bases()) {
2480	const APValue &BaseValue = Value.getStructBase(i: BaseIndex);
2481	if (!BaseValue.hasValue()) {
2482	SourceLocation TypeBeginLoc = BS.getBaseTypeLoc();
2483	Info.FFDiag(TypeBeginLoc, diag::note_constexpr_uninitialized_base)
2484	<< BS.getType() << SourceRange(TypeBeginLoc, BS.getEndLoc());
2485	return false;
2486	}
2487	if (!CheckEvaluationResult(CERK, Info, DiagLoc, Type: BS.getType(), Value: BaseValue,
2488	Kind, /*SubobjectDecl=*/nullptr,
2489	CheckedTemps))
2490	return false;
2491	++BaseIndex;
2492	}
2493	}
2494	for (const auto *I : RD->fields()) {
2495	if (I->isUnnamedBitField())
2496	continue;
2497
2498	if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
2499	Value.getStructField(i: I->getFieldIndex()), Kind,
2500	I, CheckedTemps))
2501	return false;
2502	}
2503	}
2504
2505	if (Value.isLValue() &&
2506	CERK == CheckEvaluationResultKind::ConstantExpression) {
2507	LValue LVal;
2508	LVal.setFrom(Ctx&: Info.Ctx, V: Value);
2509	return CheckLValueConstantExpression(Info, Loc: DiagLoc, Type, LVal, Kind,
2510	CheckedTemps);
2511	}
2512
2513	if (Value.isMemberPointer() &&
2514	CERK == CheckEvaluationResultKind::ConstantExpression)
2515	return CheckMemberPointerConstantExpression(Info, Loc: DiagLoc, Type, Value, Kind);
2516
2517	// Everything else is fine.
2518	return true;
2519	}
2520
2521	/// Check that this core constant expression value is a valid value for a
2522	/// constant expression. If not, report an appropriate diagnostic. Does not
2523	/// check that the expression is of literal type.
2524	static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
2525	QualType Type, const APValue &Value,
2526	ConstantExprKind Kind) {
2527	// Nothing to check for a constant expression of type 'cv void'.
2528	if (Type->isVoidType())
2529	return true;
2530
2531	CheckedTemporaries CheckedTemps;
2532	return CheckEvaluationResult(CERK: CheckEvaluationResultKind::ConstantExpression,
2533	Info, DiagLoc, Type, Value, Kind,
2534	/*SubobjectDecl=*/nullptr, CheckedTemps);
2535	}
2536
2537	/// Check that this evaluated value is fully-initialized and can be loaded by
2538	/// an lvalue-to-rvalue conversion.
2539	static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
2540	QualType Type, const APValue &Value) {
2541	CheckedTemporaries CheckedTemps;
2542	return CheckEvaluationResult(
2543	CERK: CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
2544	Kind: ConstantExprKind::Normal, /*SubobjectDecl=*/nullptr, CheckedTemps);
2545	}
2546
2547	/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2548	/// "the allocated storage is deallocated within the evaluation".
2549	static bool CheckMemoryLeaks(EvalInfo &Info) {
2550	if (!Info.HeapAllocs.empty()) {
2551	// We can still fold to a constant despite a compile-time memory leak,
2552	// so long as the heap allocation isn't referenced in the result (we check
2553	// that in CheckConstantExpression).
2554	Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr,
2555	diag::note_constexpr_memory_leak)
2556	<< unsigned(Info.HeapAllocs.size() - 1);
2557	}
2558	return true;
2559	}
2560
2561	static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
2562	// A null base expression indicates a null pointer. These are always
2563	// evaluatable, and they are false unless the offset is zero.
2564	if (!Value.getLValueBase()) {
2565	// TODO: Should a non-null pointer with an offset of zero evaluate to true?
2566	Result = !Value.getLValueOffset().isZero();
2567	return true;
2568	}
2569
2570	// We have a non-null base. These are generally known to be true, but if it's
2571	// a weak declaration it can be null at runtime.
2572	Result = true;
2573	const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
2574	return !Decl || !Decl->isWeak();
2575	}
2576
2577	static bool HandleConversionToBool(const APValue &Val, bool &Result) {
2578	// TODO: This function should produce notes if it fails.
2579	switch (Val.getKind()) {
2580	case APValue::None:
2581	case APValue::Indeterminate:
2582	return false;
2583	case APValue::Int:
2584	Result = Val.getInt().getBoolValue();
2585	return true;
2586	case APValue::FixedPoint:
2587	Result = Val.getFixedPoint().getBoolValue();
2588	return true;
2589	case APValue::Float:
2590	Result = !Val.getFloat().isZero();
2591	return true;
2592	case APValue::ComplexInt:
2593	Result = Val.getComplexIntReal().getBoolValue() ||
2594	Val.getComplexIntImag().getBoolValue();
2595	return true;
2596	case APValue::ComplexFloat:
2597	Result = !Val.getComplexFloatReal().isZero() ||
2598	!Val.getComplexFloatImag().isZero();
2599	return true;
2600	case APValue::LValue:
2601	return EvalPointerValueAsBool(Value: Val, Result);
2602	case APValue::MemberPointer:
2603	if (Val.getMemberPointerDecl() && Val.getMemberPointerDecl()->isWeak()) {
2604	return false;
2605	}
2606	Result = Val.getMemberPointerDecl();
2607	return true;
2608	case APValue::Vector:
2609	case APValue::Array:
2610	case APValue::Struct:
2611	case APValue::Union:
2612	case APValue::AddrLabelDiff:
2613	return false;
2614	}
2615
2616	llvm_unreachable("unknown APValue kind");
2617	}
2618
2619	static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
2620	EvalInfo &Info) {
2621	assert(!E->isValueDependent());
2622	assert(E->isPRValue() && "missing lvalue-to-rvalue conv in bool condition");
2623	APValue Val;
2624	if (!Evaluate(Result&: Val, Info, E))
2625	return false;
2626	return HandleConversionToBool(Val, Result);
2627	}
2628
2629	template<typename T>
2630	static bool HandleOverflow(EvalInfo &Info, const Expr *E,
2631	const T &SrcValue, QualType DestType) {
2632	Info.CCEDiag(E, diag::note_constexpr_overflow)
2633	<< SrcValue << DestType;
2634	return Info.noteUndefinedBehavior();
2635	}
2636
2637	static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
2638	QualType SrcType, const APFloat &Value,
2639	QualType DestType, APSInt &Result) {
2640	unsigned DestWidth = Info.Ctx.getIntWidth(T: DestType);
2641	// Determine whether we are converting to unsigned or signed.
2642	bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
2643
2644	Result = APSInt(DestWidth, !DestSigned);
2645	bool ignored;
2646	if (Value.convertToInteger(Result, RM: llvm::APFloat::rmTowardZero, IsExact: &ignored)
2647	& APFloat::opInvalidOp)
2648	return HandleOverflow(Info, E, SrcValue: Value, DestType);
2649	return true;
2650	}
2651
2652	/// Get rounding mode to use in evaluation of the specified expression.
2653	///
2654	/// If rounding mode is unknown at compile time, still try to evaluate the
2655	/// expression. If the result is exact, it does not depend on rounding mode.
2656	/// So return "tonearest" mode instead of "dynamic".
2657	static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E) {
2658	llvm::RoundingMode RM =
2659	E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts()).getRoundingMode();
2660	if (RM == llvm::RoundingMode::Dynamic)
2661	RM = llvm::RoundingMode::NearestTiesToEven;
2662	return RM;
2663	}
2664
2665	/// Check if the given evaluation result is allowed for constant evaluation.
2666	static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E,
2667	APFloat::opStatus St) {
2668	// In a constant context, assume that any dynamic rounding mode or FP
2669	// exception state matches the default floating-point environment.
2670	if (Info.InConstantContext)
2671	return true;
2672
2673	FPOptions FPO = E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts());
2674	if ((St & APFloat::opInexact) &&
2675	FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) {
2676	// Inexact result means that it depends on rounding mode. If the requested
2677	// mode is dynamic, the evaluation cannot be made in compile time.
2678	Info.FFDiag(E, diag::note_constexpr_dynamic_rounding);
2679	return false;
2680	}
2681
2682	if ((St != APFloat::opOK) &&
2683	(FPO.getRoundingMode() == llvm::RoundingMode::Dynamic ||
2684	FPO.getExceptionMode() != LangOptions::FPE_Ignore ||
2685	FPO.getAllowFEnvAccess())) {
2686	Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
2687	return false;
2688	}
2689
2690	if ((St & APFloat::opStatus::opInvalidOp) &&
2691	FPO.getExceptionMode() != LangOptions::FPE_Ignore) {
2692	// There is no usefully definable result.
2693	Info.FFDiag(E);
2694	return false;
2695	}
2696
2697	// FIXME: if:
2698	// - evaluation triggered other FP exception, and
2699	// - exception mode is not "ignore", and
2700	// - the expression being evaluated is not a part of global variable
2701	// initializer,
2702	// the evaluation probably need to be rejected.
2703	return true;
2704	}
2705
2706	static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
2707	QualType SrcType, QualType DestType,
2708	APFloat &Result) {
2709	assert(isa<CastExpr>(E) || isa<CompoundAssignOperator>(E));
2710	llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
2711	APFloat::opStatus St;
2712	APFloat Value = Result;
2713	bool ignored;
2714	St = Result.convert(ToSemantics: Info.Ctx.getFloatTypeSemantics(T: DestType), RM, losesInfo: &ignored);
2715	return checkFloatingPointResult(Info, E, St);
2716	}
2717
2718	static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
2719	QualType DestType, QualType SrcType,
2720	const APSInt &Value) {
2721	unsigned DestWidth = Info.Ctx.getIntWidth(T: DestType);
2722	// Figure out if this is a truncate, extend or noop cast.
2723	// If the input is signed, do a sign extend, noop, or truncate.
2724	APSInt Result = Value.extOrTrunc(width: DestWidth);
2725	Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
2726	if (DestType->isBooleanType())
2727	Result = Value.getBoolValue();
2728	return Result;
2729	}
2730
2731	static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
2732	const FPOptions FPO,
2733	QualType SrcType, const APSInt &Value,
2734	QualType DestType, APFloat &Result) {
2735	Result = APFloat(Info.Ctx.getFloatTypeSemantics(T: DestType), 1);
2736	llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
2737	APFloat::opStatus St = Result.convertFromAPInt(Input: Value, IsSigned: Value.isSigned(), RM);
2738	return checkFloatingPointResult(Info, E, St);
2739	}
2740
2741	static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
2742	APValue &Value, const FieldDecl *FD) {
2743	assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
2744
2745	if (!Value.isInt()) {
2746	// Trying to store a pointer-cast-to-integer into a bitfield.
2747	// FIXME: In this case, we should provide the diagnostic for casting
2748	// a pointer to an integer.
2749	assert(Value.isLValue() && "integral value neither int nor lvalue?");
2750	Info.FFDiag(E);
2751	return false;
2752	}
2753
2754	APSInt &Int = Value.getInt();
2755	unsigned OldBitWidth = Int.getBitWidth();
2756	unsigned NewBitWidth = FD->getBitWidthValue(Ctx: Info.Ctx);
2757	if (NewBitWidth < OldBitWidth)
2758	Int = Int.trunc(width: NewBitWidth).extend(width: OldBitWidth);
2759	return true;
2760	}
2761
2762	/// Perform the given integer operation, which is known to need at most BitWidth
2763	/// bits, and check for overflow in the original type (if that type was not an
2764	/// unsigned type).
2765	template<typename Operation>
2766	static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
2767	const APSInt &LHS, const APSInt &RHS,
2768	unsigned BitWidth, Operation Op,
2769	APSInt &Result) {
2770	if (LHS.isUnsigned()) {
2771	Result = Op(LHS, RHS);
2772	return true;
2773	}
2774
2775	APSInt Value(Op(LHS.extend(width: BitWidth), RHS.extend(width: BitWidth)), false);
2776	Result = Value.trunc(width: LHS.getBitWidth());
2777	if (Result.extend(width: BitWidth) != Value) {
2778	if (Info.checkingForUndefinedBehavior())
2779	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
2780	diag::warn_integer_constant_overflow)
2781	<< toString(Result, 10, Result.isSigned(), /*formatAsCLiteral=*/false,
2782	/*UpperCase=*/true, /*InsertSeparators=*/true)
2783	<< E->getType() << E->getSourceRange();
2784	return HandleOverflow(Info, E, SrcValue: Value, DestType: E->getType());
2785	}
2786	return true;
2787	}
2788
2789	/// Perform the given binary integer operation.
2790	static bool handleIntIntBinOp(EvalInfo &Info, const BinaryOperator *E,
2791	const APSInt &LHS, BinaryOperatorKind Opcode,
2792	APSInt RHS, APSInt &Result) {
2793	bool HandleOverflowResult = true;
2794	switch (Opcode) {
2795	default:
2796	Info.FFDiag(E);
2797	return false;
2798	case BO_Mul:
2799	return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2800	std::multiplies<APSInt>(), Result);
2801	case BO_Add:
2802	return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2803	std::plus<APSInt>(), Result);
2804	case BO_Sub:
2805	return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2806	std::minus<APSInt>(), Result);
2807	case BO_And: Result = LHS & RHS; return true;
2808	case BO_Xor: Result = LHS ^ RHS; return true;
2809	case BO_Or: Result = LHS | RHS; return true;
2810	case BO_Div:
2811	case BO_Rem:
2812	if (RHS == 0) {
2813	Info.FFDiag(E, diag::note_expr_divide_by_zero)
2814	<< E->getRHS()->getSourceRange();
2815	return false;
2816	}
2817	// Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2818	// this operation and gives the two's complement result.
2819	if (RHS.isNegative() && RHS.isAllOnes() && LHS.isSigned() &&
2820	LHS.isMinSignedValue())
2821	HandleOverflowResult = HandleOverflow(
2822	Info, E, -LHS.extend(width: LHS.getBitWidth() + 1), E->getType());
2823	Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2824	return HandleOverflowResult;
2825	case BO_Shl: {
2826	if (Info.getLangOpts().OpenCL)
2827	// OpenCL 6.3j: shift values are effectively % word size of LHS.
2828	RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2829	static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2830	RHS.isUnsigned());
2831	else if (RHS.isSigned() && RHS.isNegative()) {
2832	// During constant-folding, a negative shift is an opposite shift. Such
2833	// a shift is not a constant expression.
2834	Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2835	RHS = -RHS;
2836	goto shift_right;
2837	}
2838	shift_left:
2839	// C++11 [expr.shift]p1: Shift width must be less than the bit width of
2840	// the shifted type.
2841	unsigned SA = (unsigned) RHS.getLimitedValue(Limit: LHS.getBitWidth()-1);
2842	if (SA != RHS) {
2843	Info.CCEDiag(E, diag::note_constexpr_large_shift)
2844	<< RHS << E->getType() << LHS.getBitWidth();
2845	} else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
2846	// C++11 [expr.shift]p2: A signed left shift must have a non-negative
2847	// operand, and must not overflow the corresponding unsigned type.
2848	// C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
2849	// E1 x 2^E2 module 2^N.
2850	if (LHS.isNegative())
2851	Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2852	else if (LHS.countl_zero() < SA)
2853	Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2854	}
2855	Result = LHS << SA;
2856	return true;
2857	}
2858	case BO_Shr: {
2859	if (Info.getLangOpts().OpenCL)
2860	// OpenCL 6.3j: shift values are effectively % word size of LHS.
2861	RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2862	static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2863	RHS.isUnsigned());
2864	else if (RHS.isSigned() && RHS.isNegative()) {
2865	// During constant-folding, a negative shift is an opposite shift. Such a
2866	// shift is not a constant expression.
2867	Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2868	RHS = -RHS;
2869	goto shift_left;
2870	}
2871	shift_right:
2872	// C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2873	// shifted type.
2874	unsigned SA = (unsigned) RHS.getLimitedValue(Limit: LHS.getBitWidth()-1);
2875	if (SA != RHS)
2876	Info.CCEDiag(E, diag::note_constexpr_large_shift)
2877	<< RHS << E->getType() << LHS.getBitWidth();
2878	Result = LHS >> SA;
2879	return true;
2880	}
2881
2882	case BO_LT: Result = LHS < RHS; return true;
2883	case BO_GT: Result = LHS > RHS; return true;
2884	case BO_LE: Result = LHS <= RHS; return true;
2885	case BO_GE: Result = LHS >= RHS; return true;
2886	case BO_EQ: Result = LHS == RHS; return true;
2887	case BO_NE: Result = LHS != RHS; return true;
2888	case BO_Cmp:
2889	llvm_unreachable("BO_Cmp should be handled elsewhere");
2890	}
2891	}
2892
2893	/// Perform the given binary floating-point operation, in-place, on LHS.
2894	static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E,
2895	APFloat &LHS, BinaryOperatorKind Opcode,
2896	const APFloat &RHS) {
2897	llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
2898	APFloat::opStatus St;
2899	switch (Opcode) {
2900	default:
2901	Info.FFDiag(E);
2902	return false;
2903	case BO_Mul:
2904	St = LHS.multiply(RHS, RM);
2905	break;
2906	case BO_Add:
2907	St = LHS.add(RHS, RM);
2908	break;
2909	case BO_Sub:
2910	St = LHS.subtract(RHS, RM);
2911	break;
2912	case BO_Div:
2913	// [expr.mul]p4:
2914	// If the second operand of / or % is zero the behavior is undefined.
2915	if (RHS.isZero())
2916	Info.CCEDiag(E, diag::note_expr_divide_by_zero);
2917	St = LHS.divide(RHS, RM);
2918	break;
2919	}
2920
2921	// [expr.pre]p4:
2922	// If during the evaluation of an expression, the result is not
2923	// mathematically defined [...], the behavior is undefined.
2924	// FIXME: C++ rules require us to not conform to IEEE 754 here.
2925	if (LHS.isNaN()) {
2926	Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2927	return Info.noteUndefinedBehavior();
2928	}
2929
2930	return checkFloatingPointResult(Info, E, St);
2931	}
2932
2933	static bool handleLogicalOpForVector(const APInt &LHSValue,
2934	BinaryOperatorKind Opcode,
2935	const APInt &RHSValue, APInt &Result) {
2936	bool LHS = (LHSValue != 0);
2937	bool RHS = (RHSValue != 0);
2938
2939	if (Opcode == BO_LAnd)
2940	Result = LHS && RHS;
2941	else
2942	Result = LHS || RHS;
2943	return true;
2944	}
2945	static bool handleLogicalOpForVector(const APFloat &LHSValue,
2946	BinaryOperatorKind Opcode,
2947	const APFloat &RHSValue, APInt &Result) {
2948	bool LHS = !LHSValue.isZero();
2949	bool RHS = !RHSValue.isZero();
2950
2951	if (Opcode == BO_LAnd)
2952	Result = LHS && RHS;
2953	else
2954	Result = LHS || RHS;
2955	return true;
2956	}
2957
2958	static bool handleLogicalOpForVector(const APValue &LHSValue,
2959	BinaryOperatorKind Opcode,
2960	const APValue &RHSValue, APInt &Result) {
2961	// The result is always an int type, however operands match the first.
2962	if (LHSValue.getKind() == APValue::Int)
2963	return handleLogicalOpForVector(LHSValue: LHSValue.getInt(), Opcode,
2964	RHSValue: RHSValue.getInt(), Result);
2965	assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
2966	return handleLogicalOpForVector(LHSValue: LHSValue.getFloat(), Opcode,
2967	RHSValue: RHSValue.getFloat(), Result);
2968	}
2969
2970	template <typename APTy>
2971	static bool
2972	handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
2973	const APTy &RHSValue, APInt &Result) {
2974	switch (Opcode) {
2975	default:
2976	llvm_unreachable("unsupported binary operator");
2977	case BO_EQ:
2978	Result = (LHSValue == RHSValue);
2979	break;
2980	case BO_NE:
2981	Result = (LHSValue != RHSValue);
2982	break;
2983	case BO_LT:
2984	Result = (LHSValue < RHSValue);
2985	break;
2986	case BO_GT:
2987	Result = (LHSValue > RHSValue);
2988	break;
2989	case BO_LE:
2990	Result = (LHSValue <= RHSValue);
2991	break;
2992	case BO_GE:
2993	Result = (LHSValue >= RHSValue);
2994	break;
2995	}
2996
2997	// The boolean operations on these vector types use an instruction that
2998	// results in a mask of '-1' for the 'truth' value. Ensure that we negate 1
2999	// to -1 to make sure that we produce the correct value.
3000	Result.negate();
3001
3002	return true;
3003	}
3004
3005	static bool handleCompareOpForVector(const APValue &LHSValue,
3006	BinaryOperatorKind Opcode,
3007	const APValue &RHSValue, APInt &Result) {
3008	// The result is always an int type, however operands match the first.
3009	if (LHSValue.getKind() == APValue::Int)
3010	return handleCompareOpForVectorHelper(LHSValue: LHSValue.getInt(), Opcode,
3011	RHSValue: RHSValue.getInt(), Result);
3012	assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
3013	return handleCompareOpForVectorHelper(LHSValue: LHSValue.getFloat(), Opcode,
3014	RHSValue: RHSValue.getFloat(), Result);
3015	}
3016
3017	// Perform binary operations for vector types, in place on the LHS.
3018	static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E,
3019	BinaryOperatorKind Opcode,
3020	APValue &LHSValue,
3021	const APValue &RHSValue) {
3022	assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&
3023	"Operation not supported on vector types");
3024
3025	const auto *VT = E->getType()->castAs<VectorType>();
3026	unsigned NumElements = VT->getNumElements();
3027	QualType EltTy = VT->getElementType();
3028
3029	// In the cases (typically C as I've observed) where we aren't evaluating
3030	// constexpr but are checking for cases where the LHS isn't yet evaluatable,
3031	// just give up.
3032	if (!LHSValue.isVector()) {
3033	assert(LHSValue.isLValue() &&
3034	"A vector result that isn't a vector OR uncalculated LValue");
3035	Info.FFDiag(E);
3036	return false;
3037	}
3038
3039	assert(LHSValue.getVectorLength() == NumElements &&
3040	RHSValue.getVectorLength() == NumElements && "Different vector sizes");
3041
3042	SmallVector<APValue, 4> ResultElements;
3043
3044	for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
3045	APValue LHSElt = LHSValue.getVectorElt(I: EltNum);
3046	APValue RHSElt = RHSValue.getVectorElt(I: EltNum);
3047
3048	if (EltTy->isIntegerType()) {
3049	APSInt EltResult{Info.Ctx.getIntWidth(T: EltTy),
3050	EltTy->isUnsignedIntegerType()};
3051	bool Success = true;
3052
3053	if (BinaryOperator::isLogicalOp(Opc: Opcode))
3054	Success = handleLogicalOpForVector(LHSValue: LHSElt, Opcode, RHSValue: RHSElt, Result&: EltResult);
3055	else if (BinaryOperator::isComparisonOp(Opc: Opcode))
3056	Success = handleCompareOpForVector(LHSValue: LHSElt, Opcode, RHSValue: RHSElt, Result&: EltResult);
3057	else
3058	Success = handleIntIntBinOp(Info, E, LHS: LHSElt.getInt(), Opcode,
3059	RHS: RHSElt.getInt(), Result&: EltResult);
3060
3061	if (!Success) {
3062	Info.FFDiag(E);
3063	return false;
3064	}
3065	ResultElements.emplace_back(Args&: EltResult);
3066
3067	} else if (EltTy->isFloatingType()) {
3068	assert(LHSElt.getKind() == APValue::Float &&
3069	RHSElt.getKind() == APValue::Float &&
3070	"Mismatched LHS/RHS/Result Type");
3071	APFloat LHSFloat = LHSElt.getFloat();
3072
3073	if (!handleFloatFloatBinOp(Info, E, LHS&: LHSFloat, Opcode,
3074	RHS: RHSElt.getFloat())) {
3075	Info.FFDiag(E);
3076	return false;
3077	}
3078
3079	ResultElements.emplace_back(Args&: LHSFloat);
3080	}
3081	}
3082
3083	LHSValue = APValue(ResultElements.data(), ResultElements.size());
3084	return true;
3085	}
3086
3087	/// Cast an lvalue referring to a base subobject to a derived class, by
3088	/// truncating the lvalue's path to the given length.
3089	static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
3090	const RecordDecl *TruncatedType,
3091	unsigned TruncatedElements) {
3092	SubobjectDesignator &D = Result.Designator;
3093
3094	// Check we actually point to a derived class object.
3095	if (TruncatedElements == D.Entries.size())
3096	return true;
3097	assert(TruncatedElements >= D.MostDerivedPathLength &&
3098	"not casting to a derived class");
3099	if (!Result.checkSubobject(Info, E, CSK: CSK_Derived))
3100	return false;
3101
3102	// Truncate the path to the subobject, and remove any derived-to-base offsets.
3103	const RecordDecl *RD = TruncatedType;
3104	for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
3105	if (RD->isInvalidDecl()) return false;
3106	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
3107	const CXXRecordDecl *Base = getAsBaseClass(E: D.Entries[I]);
3108	if (isVirtualBaseClass(E: D.Entries[I]))
3109	Result.Offset -= Layout.getVBaseClassOffset(VBase: Base);
3110	else
3111	Result.Offset -= Layout.getBaseClassOffset(Base);
3112	RD = Base;
3113	}
3114	D.Entries.resize(N: TruncatedElements);
3115	return true;
3116	}
3117
3118	static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3119	const CXXRecordDecl *Derived,
3120	const CXXRecordDecl *Base,
3121	const ASTRecordLayout *RL = nullptr) {
3122	if (!RL) {
3123	if (Derived->isInvalidDecl()) return false;
3124	RL = &Info.Ctx.getASTRecordLayout(Derived);
3125	}
3126
3127	Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
3128	Obj.addDecl(Info, E, Base, /*Virtual*/ false);
3129	return true;
3130	}
3131
3132	static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3133	const CXXRecordDecl *DerivedDecl,
3134	const CXXBaseSpecifier *Base) {
3135	const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
3136
3137	if (!Base->isVirtual())
3138	return HandleLValueDirectBase(Info, E, Obj, Derived: DerivedDecl, Base: BaseDecl);
3139
3140	SubobjectDesignator &D = Obj.Designator;
3141	if (D.Invalid)
3142	return false;
3143
3144	// Extract most-derived object and corresponding type.
3145	DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
3146	if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
3147	return false;
3148
3149	// Find the virtual base class.
3150	if (DerivedDecl->isInvalidDecl()) return false;
3151	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
3152	Obj.getLValueOffset() += Layout.getVBaseClassOffset(VBase: BaseDecl);
3153	Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
3154	return true;
3155	}
3156
3157	static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
3158	QualType Type, LValue &Result) {
3159	for (CastExpr::path_const_iterator PathI = E->path_begin(),
3160	PathE = E->path_end();
3161	PathI != PathE; ++PathI) {
3162	if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
3163	*PathI))
3164	return false;
3165	Type = (*PathI)->getType();
3166	}
3167	return true;
3168	}
3169
3170	/// Cast an lvalue referring to a derived class to a known base subobject.
3171	static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
3172	const CXXRecordDecl *DerivedRD,
3173	const CXXRecordDecl *BaseRD) {
3174	CXXBasePaths Paths(/*FindAmbiguities=*/false,
3175	/*RecordPaths=*/true, /*DetectVirtual=*/false);
3176	if (!DerivedRD->isDerivedFrom(Base: BaseRD, Paths))
3177	llvm_unreachable("Class must be derived from the passed in base class!");
3178
3179	for (CXXBasePathElement &Elem : Paths.front())
3180	if (!HandleLValueBase(Info, E, Obj&: Result, DerivedDecl: Elem.Class, Base: Elem.Base))
3181	return false;
3182	return true;
3183	}
3184
3185	/// Update LVal to refer to the given field, which must be a member of the type
3186	/// currently described by LVal.
3187	static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
3188	const FieldDecl *FD,
3189	const ASTRecordLayout *RL = nullptr) {
3190	if (!RL) {
3191	if (FD->getParent()->isInvalidDecl()) return false;
3192	RL = &Info.Ctx.getASTRecordLayout(D: FD->getParent());
3193	}
3194
3195	unsigned I = FD->getFieldIndex();
3196	LVal.adjustOffset(N: Info.Ctx.toCharUnitsFromBits(BitSize: RL->getFieldOffset(FieldNo: I)));
3197	LVal.addDecl(Info, E, FD);
3198	return true;
3199	}
3200
3201	/// Update LVal to refer to the given indirect field.
3202	static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
3203	LValue &LVal,
3204	const IndirectFieldDecl *IFD) {
3205	for (const auto *C : IFD->chain())
3206	if (!HandleLValueMember(Info, E, LVal, FD: cast<FieldDecl>(Val: C)))
3207	return false;
3208	return true;
3209	}
3210
3211	enum class SizeOfType {
3212	SizeOf,
3213	DataSizeOf,
3214	};
3215
3216	/// Get the size of the given type in char units.
3217	static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, QualType Type,
3218	CharUnits &Size, SizeOfType SOT = SizeOfType::SizeOf) {
3219	// sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
3220	// extension.
3221	if (Type->isVoidType() || Type->isFunctionType()) {
3222	Size = CharUnits::One();
3223	return true;
3224	}
3225
3226	if (Type->isDependentType()) {
3227	Info.FFDiag(Loc);
3228	return false;
3229	}
3230
3231	if (!Type->isConstantSizeType()) {
3232	// sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
3233	// FIXME: Better diagnostic.
3234	Info.FFDiag(Loc);
3235	return false;
3236	}
3237
3238	if (SOT == SizeOfType::SizeOf)
3239	Size = Info.Ctx.getTypeSizeInChars(T: Type);
3240	else
3241	Size = Info.Ctx.getTypeInfoDataSizeInChars(T: Type).Width;
3242	return true;
3243	}
3244
3245	/// Update a pointer value to model pointer arithmetic.
3246	/// \param Info - Information about the ongoing evaluation.
3247	/// \param E - The expression being evaluated, for diagnostic purposes.
3248	/// \param LVal - The pointer value to be updated.
3249	/// \param EltTy - The pointee type represented by LVal.
3250	/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
3251	static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3252	LValue &LVal, QualType EltTy,
3253	APSInt Adjustment) {
3254	CharUnits SizeOfPointee;
3255	if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: EltTy, Size&: SizeOfPointee))
3256	return false;
3257
3258	LVal.adjustOffsetAndIndex(Info, E, Index: Adjustment, ElementSize: SizeOfPointee);
3259	return true;
3260	}
3261
3262	static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3263	LValue &LVal, QualType EltTy,
3264	int64_t Adjustment) {
3265	return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
3266	Adjustment: APSInt::get(X: Adjustment));
3267	}
3268
3269	/// Update an lvalue to refer to a component of a complex number.
3270	/// \param Info - Information about the ongoing evaluation.
3271	/// \param LVal - The lvalue to be updated.
3272	/// \param EltTy - The complex number's component type.
3273	/// \param Imag - False for the real component, true for the imaginary.
3274	static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
3275	LValue &LVal, QualType EltTy,
3276	bool Imag) {
3277	if (Imag) {
3278	CharUnits SizeOfComponent;
3279	if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: EltTy, Size&: SizeOfComponent))
3280	return false;
3281	LVal.Offset += SizeOfComponent;
3282	}
3283	LVal.addComplex(Info, E, EltTy, Imag);
3284	return true;
3285	}
3286
3287	/// Try to evaluate the initializer for a variable declaration.
3288	///
3289	/// \param Info Information about the ongoing evaluation.
3290	/// \param E An expression to be used when printing diagnostics.
3291	/// \param VD The variable whose initializer should be obtained.
3292	/// \param Version The version of the variable within the frame.
3293	/// \param Frame The frame in which the variable was created. Must be null
3294	/// if this variable is not local to the evaluation.
3295	/// \param Result Filled in with a pointer to the value of the variable.
3296	static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
3297	const VarDecl *VD, CallStackFrame *Frame,
3298	unsigned Version, APValue *&Result) {
3299	APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
3300
3301	// If this is a local variable, dig out its value.
3302	if (Frame) {
3303	Result = Frame->getTemporary(Key: VD, Version);
3304	if (Result)
3305	return true;
3306
3307	if (!isa<ParmVarDecl>(Val: VD)) {
3308	// Assume variables referenced within a lambda's call operator that were
3309	// not declared within the call operator are captures and during checking
3310	// of a potential constant expression, assume they are unknown constant
3311	// expressions.
3312	assert(isLambdaCallOperator(Frame->Callee) &&
3313	(VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
3314	"missing value for local variable");
3315	if (Info.checkingPotentialConstantExpression())
3316	return false;
3317	// FIXME: This diagnostic is bogus; we do support captures. Is this code
3318	// still reachable at all?
3319	Info.FFDiag(E->getBeginLoc(),
3320	diag::note_unimplemented_constexpr_lambda_feature_ast)
3321	<< "captures not currently allowed";
3322	return false;
3323	}
3324	}
3325
3326	// If we're currently evaluating the initializer of this declaration, use that
3327	// in-flight value.
3328	if (Info.EvaluatingDecl == Base) {
3329	Result = Info.EvaluatingDeclValue;
3330	return true;
3331	}
3332
3333	if (isa<ParmVarDecl>(Val: VD)) {
3334	// Assume parameters of a potential constant expression are usable in
3335	// constant expressions.
3336	if (!Info.checkingPotentialConstantExpression() ||
3337	!Info.CurrentCall->Callee ||
3338	!Info.CurrentCall->Callee->Equals(DC: VD->getDeclContext())) {
3339	if (Info.getLangOpts().CPlusPlus11) {
3340	Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown)
3341	<< VD;
3342	NoteLValueLocation(Info, Base);
3343	} else {
3344	Info.FFDiag(E);
3345	}
3346	}
3347	return false;
3348	}
3349
3350	if (E->isValueDependent())
3351	return false;
3352
3353	// Dig out the initializer, and use the declaration which it's attached to.
3354	// FIXME: We should eventually check whether the variable has a reachable
3355	// initializing declaration.
3356	const Expr *Init = VD->getAnyInitializer(D&: VD);
3357	if (!Init) {
3358	// Don't diagnose during potential constant expression checking; an
3359	// initializer might be added later.
3360	if (!Info.checkingPotentialConstantExpression()) {
3361	Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1)
3362	<< VD;
3363	NoteLValueLocation(Info, Base);
3364	}
3365	return false;
3366	}
3367
3368	if (Init->isValueDependent()) {
3369	// The DeclRefExpr is not value-dependent, but the variable it refers to
3370	// has a value-dependent initializer. This should only happen in
3371	// constant-folding cases, where the variable is not actually of a suitable
3372	// type for use in a constant expression (otherwise the DeclRefExpr would
3373	// have been value-dependent too), so diagnose that.
3374	assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx));
3375	if (!Info.checkingPotentialConstantExpression()) {
3376	Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
3377	? diag::note_constexpr_ltor_non_constexpr
3378	: diag::note_constexpr_ltor_non_integral, 1)
3379	<< VD << VD->getType();
3380	NoteLValueLocation(Info, Base);
3381	}
3382	return false;
3383	}
3384
3385	// Check that we can fold the initializer. In C++, we will have already done
3386	// this in the cases where it matters for conformance.
3387	if (!VD->evaluateValue()) {
3388	Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3389	NoteLValueLocation(Info, Base);
3390	return false;
3391	}
3392
3393	// Check that the variable is actually usable in constant expressions. For a
3394	// const integral variable or a reference, we might have a non-constant
3395	// initializer that we can nonetheless evaluate the initializer for. Such
3396	// variables are not usable in constant expressions. In C++98, the
3397	// initializer also syntactically needs to be an ICE.
3398	//
3399	// FIXME: We don't diagnose cases that aren't potentially usable in constant
3400	// expressions here; doing so would regress diagnostics for things like
3401	// reading from a volatile constexpr variable.
3402	if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() &&
3403	VD->mightBeUsableInConstantExpressions(C: Info.Ctx)) ||
3404	((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) &&
3405	!Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Context: Info.Ctx))) {
3406	Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3407	NoteLValueLocation(Info, Base);
3408	}
3409
3410	// Never use the initializer of a weak variable, not even for constant
3411	// folding. We can't be sure that this is the definition that will be used.
3412	if (VD->isWeak()) {
3413	Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD;
3414	NoteLValueLocation(Info, Base);
3415	return false;
3416	}
3417
3418	Result = VD->getEvaluatedValue();
3419	return true;
3420	}
3421
3422	/// Get the base index of the given base class within an APValue representing
3423	/// the given derived class.
3424	static unsigned getBaseIndex(const CXXRecordDecl *Derived,
3425	const CXXRecordDecl *Base) {
3426	Base = Base->getCanonicalDecl();
3427	unsigned Index = 0;
3428	for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
3429	E = Derived->bases_end(); I != E; ++I, ++Index) {
3430	if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
3431	return Index;
3432	}
3433
3434	llvm_unreachable("base class missing from derived class's bases list");
3435	}
3436
3437	/// Extract the value of a character from a string literal.
3438	static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
3439	uint64_t Index) {
3440	assert(!isa<SourceLocExpr>(Lit) &&
3441	"SourceLocExpr should have already been converted to a StringLiteral");
3442
3443	// FIXME: Support MakeStringConstant
3444	if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Val: Lit)) {
3445	std::string Str;
3446	Info.Ctx.getObjCEncodingForType(T: ObjCEnc->getEncodedType(), S&: Str);
3447	assert(Index <= Str.size() && "Index too large");
3448	return APSInt::getUnsigned(X: Str.c_str()[Index]);
3449	}
3450
3451	if (auto PE = dyn_cast<PredefinedExpr>(Val: Lit))
3452	Lit = PE->getFunctionName();
3453	const StringLiteral *S = cast<StringLiteral>(Val: Lit);
3454	const ConstantArrayType *CAT =
3455	Info.Ctx.getAsConstantArrayType(T: S->getType());
3456	assert(CAT && "string literal isn't an array");
3457	QualType CharType = CAT->getElementType();
3458	assert(CharType->isIntegerType() && "unexpected character type");
3459	APSInt Value(Info.Ctx.getTypeSize(T: CharType),
3460	CharType->isUnsignedIntegerType());
3461	if (Index < S->getLength())
3462	Value = S->getCodeUnit(i: Index);
3463	return Value;
3464	}
3465
3466	// Expand a string literal into an array of characters.
3467	//
3468	// FIXME: This is inefficient; we should probably introduce something similar
3469	// to the LLVM ConstantDataArray to make this cheaper.
3470	static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
3471	APValue &Result,
3472	QualType AllocType = QualType()) {
3473	const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
3474	T: AllocType.isNull() ? S->getType() : AllocType);
3475	assert(CAT && "string literal isn't an array");
3476	QualType CharType = CAT->getElementType();
3477	assert(CharType->isIntegerType() && "unexpected character type");
3478
3479	unsigned Elts = CAT->getZExtSize();
3480	Result = APValue(APValue::UninitArray(),
3481	std::min(a: S->getLength(), b: Elts), Elts);
3482	APSInt Value(Info.Ctx.getTypeSize(T: CharType),
3483	CharType->isUnsignedIntegerType());
3484	if (Result.hasArrayFiller())
3485	Result.getArrayFiller() = APValue(Value);
3486	for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
3487	Value = S->getCodeUnit(i: I);
3488	Result.getArrayInitializedElt(I) = APValue(Value);
3489	}
3490	}
3491
3492	// Expand an array so that it has more than Index filled elements.
3493	static void expandArray(APValue &Array, unsigned Index) {
3494	unsigned Size = Array.getArraySize();
3495	assert(Index < Size);
3496
3497	// Always at least double the number of elements for which we store a value.
3498	unsigned OldElts = Array.getArrayInitializedElts();
3499	unsigned NewElts = std::max(a: Index+1, b: OldElts * 2);
3500	NewElts = std::min(a: Size, b: std::max(a: NewElts, b: 8u));
3501
3502	// Copy the data across.
3503	APValue NewValue(APValue::UninitArray(), NewElts, Size);
3504	for (unsigned I = 0; I != OldElts; ++I)
3505	NewValue.getArrayInitializedElt(I).swap(RHS&: Array.getArrayInitializedElt(I));
3506	for (unsigned I = OldElts; I != NewElts; ++I)
3507	NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
3508	if (NewValue.hasArrayFiller())
3509	NewValue.getArrayFiller() = Array.getArrayFiller();
3510	Array.swap(RHS&: NewValue);
3511	}
3512
3513	/// Determine whether a type would actually be read by an lvalue-to-rvalue
3514	/// conversion. If it's of class type, we may assume that the copy operation
3515	/// is trivial. Note that this is never true for a union type with fields
3516	/// (because the copy always "reads" the active member) and always true for
3517	/// a non-class type.
3518	static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3519	static bool isReadByLvalueToRvalueConversion(QualType T) {
3520	CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3521	return !RD || isReadByLvalueToRvalueConversion(RD);
3522	}
3523	static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
3524	// FIXME: A trivial copy of a union copies the object representation, even if
3525	// the union is empty.
3526	if (RD->isUnion())
3527	return !RD->field_empty();
3528	if (RD->isEmpty())
3529	return false;
3530
3531	for (auto *Field : RD->fields())
3532	if (!Field->isUnnamedBitField() &&
3533	isReadByLvalueToRvalueConversion(Field->getType()))
3534	return true;
3535
3536	for (auto &BaseSpec : RD->bases())
3537	if (isReadByLvalueToRvalueConversion(T: BaseSpec.getType()))
3538	return true;
3539
3540	return false;
3541	}
3542
3543	/// Diagnose an attempt to read from any unreadable field within the specified
3544	/// type, which might be a class type.
3545	static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
3546	QualType T) {
3547	CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3548	if (!RD)
3549	return false;
3550
3551	if (!RD->hasMutableFields())
3552	return false;
3553
3554	for (auto *Field : RD->fields()) {
3555	// If we're actually going to read this field in some way, then it can't
3556	// be mutable. If we're in a union, then assigning to a mutable field
3557	// (even an empty one) can change the active member, so that's not OK.
3558	// FIXME: Add core issue number for the union case.
3559	if (Field->isMutable() &&
3560	(RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
3561	Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field;
3562	Info.Note(Field->getLocation(), diag::note_declared_at);
3563	return true;
3564	}
3565
3566	if (diagnoseMutableFields(Info, E, AK, Field->getType()))
3567	return true;
3568	}
3569
3570	for (auto &BaseSpec : RD->bases())
3571	if (diagnoseMutableFields(Info, E, AK, T: BaseSpec.getType()))
3572	return true;
3573
3574	// All mutable fields were empty, and thus not actually read.
3575	return false;
3576	}
3577
3578	static bool lifetimeStartedInEvaluation(EvalInfo &Info,
3579	APValue::LValueBase Base,
3580	bool MutableSubobject = false) {
3581	// A temporary or transient heap allocation we created.
3582	if (Base.getCallIndex() || Base.is<DynamicAllocLValue>())
3583	return true;
3584
3585	switch (Info.IsEvaluatingDecl) {
3586	case EvalInfo::EvaluatingDeclKind::None:
3587	return false;
3588
3589	case EvalInfo::EvaluatingDeclKind::Ctor:
3590	// The variable whose initializer we're evaluating.
3591	if (Info.EvaluatingDecl == Base)
3592	return true;
3593
3594	// A temporary lifetime-extended by the variable whose initializer we're
3595	// evaluating.
3596	if (auto *BaseE = Base.dyn_cast<const Expr *>())
3597	if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(Val: BaseE))
3598	return Info.EvaluatingDecl == BaseMTE->getExtendingDecl();
3599	return false;
3600
3601	case EvalInfo::EvaluatingDeclKind::Dtor:
3602	// C++2a [expr.const]p6:
3603	// [during constant destruction] the lifetime of a and its non-mutable
3604	// subobjects (but not its mutable subobjects) [are] considered to start
3605	// within e.
3606	if (MutableSubobject || Base != Info.EvaluatingDecl)
3607	return false;
3608	// FIXME: We can meaningfully extend this to cover non-const objects, but
3609	// we will need special handling: we should be able to access only
3610	// subobjects of such objects that are themselves declared const.
3611	QualType T = getType(B: Base);
3612	return T.isConstQualified() || T->isReferenceType();
3613	}
3614
3615	llvm_unreachable("unknown evaluating decl kind");
3616	}
3617
3618	static bool CheckArraySize(EvalInfo &Info, const ConstantArrayType *CAT,
3619	SourceLocation CallLoc = {}) {
3620	return Info.CheckArraySize(
3621	Loc: CAT->getSizeExpr() ? CAT->getSizeExpr()->getBeginLoc() : CallLoc,
3622	BitWidth: CAT->getNumAddressingBits(Context: Info.Ctx), ElemCount: CAT->getZExtSize(),
3623	/*Diag=*/true);
3624	}
3625
3626	namespace {
3627	/// A handle to a complete object (an object that is not a subobject of
3628	/// another object).
3629	struct CompleteObject {
3630	/// The identity of the object.
3631	APValue::LValueBase Base;
3632	/// The value of the complete object.
3633	APValue *Value;
3634	/// The type of the complete object.
3635	QualType Type;
3636
3637	CompleteObject() : Value(nullptr) {}
3638	CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
3639	: Base(Base), Value(Value), Type(Type) {}
3640
3641	bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
3642	// If this isn't a "real" access (eg, if it's just accessing the type
3643	// info), allow it. We assume the type doesn't change dynamically for
3644	// subobjects of constexpr objects (even though we'd hit UB here if it
3645	// did). FIXME: Is this right?
3646	if (!isAnyAccess(AK))
3647	return true;
3648
3649	// In C++14 onwards, it is permitted to read a mutable member whose
3650	// lifetime began within the evaluation.
3651	// FIXME: Should we also allow this in C++11?
3652	if (!Info.getLangOpts().CPlusPlus14)
3653	return false;
3654	return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
3655	}
3656
3657	explicit operator bool() const { return !Type.isNull(); }
3658	};
3659	} // end anonymous namespace
3660
3661	static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
3662	bool IsMutable = false) {
3663	// C++ [basic.type.qualifier]p1:
3664	// - A const object is an object of type const T or a non-mutable subobject
3665	// of a const object.
3666	if (ObjType.isConstQualified() && !IsMutable)
3667	SubobjType.addConst();
3668	// - A volatile object is an object of type const T or a subobject of a
3669	// volatile object.
3670	if (ObjType.isVolatileQualified())
3671	SubobjType.addVolatile();
3672	return SubobjType;
3673	}
3674
3675	/// Find the designated sub-object of an rvalue.
3676	template<typename SubobjectHandler>
3677	typename SubobjectHandler::result_type
3678	findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
3679	const SubobjectDesignator &Sub, SubobjectHandler &handler) {
3680	if (Sub.Invalid)
3681	// A diagnostic will have already been produced.
3682	return handler.failed();
3683	if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
3684	if (Info.getLangOpts().CPlusPlus11)
3685	Info.FFDiag(E, Sub.isOnePastTheEnd()
3686	? diag::note_constexpr_access_past_end
3687	: diag::note_constexpr_access_unsized_array)
3688	<< handler.AccessKind;
3689	else
3690	Info.FFDiag(E);
3691	return handler.failed();
3692	}
3693
3694	APValue *O = Obj.Value;
3695	QualType ObjType = Obj.Type;
3696	const FieldDecl *LastField = nullptr;
3697	const FieldDecl *VolatileField = nullptr;
3698
3699	// Walk the designator's path to find the subobject.
3700	for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
3701	// Reading an indeterminate value is undefined, but assigning over one is OK.
3702	if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
3703	(O->isIndeterminate() &&
3704	!isValidIndeterminateAccess(handler.AccessKind))) {
3705	if (!Info.checkingPotentialConstantExpression())
3706	Info.FFDiag(E, diag::note_constexpr_access_uninit)
3707	<< handler.AccessKind << O->isIndeterminate()
3708	<< E->getSourceRange();
3709	return handler.failed();
3710	}
3711
3712	// C++ [class.ctor]p5, C++ [class.dtor]p5:
3713	// const and volatile semantics are not applied on an object under
3714	// {con,de}struction.
3715	if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
3716	ObjType->isRecordType() &&
3717	Info.isEvaluatingCtorDtor(
3718	Base: Obj.Base,
3719	Path: llvm::ArrayRef(Sub.Entries.begin(), Sub.Entries.begin() + I)) !=
3720	ConstructionPhase::None) {
3721	ObjType = Info.Ctx.getCanonicalType(T: ObjType);
3722	ObjType.removeLocalConst();
3723	ObjType.removeLocalVolatile();
3724	}
3725
3726	// If this is our last pass, check that the final object type is OK.
3727	if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
3728	// Accesses to volatile objects are prohibited.
3729	if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
3730	if (Info.getLangOpts().CPlusPlus) {
3731	int DiagKind;
3732	SourceLocation Loc;
3733	const NamedDecl *Decl = nullptr;
3734	if (VolatileField) {
3735	DiagKind = 2;
3736	Loc = VolatileField->getLocation();
3737	Decl = VolatileField;
3738	} else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
3739	DiagKind = 1;
3740	Loc = VD->getLocation();
3741	Decl = VD;
3742	} else {
3743	DiagKind = 0;
3744	if (auto *E = Obj.Base.dyn_cast<const Expr *>())
3745	Loc = E->getExprLoc();
3746	}
3747	Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3748	<< handler.AccessKind << DiagKind << Decl;
3749	Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind;
3750	} else {
3751	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
3752	}
3753	return handler.failed();
3754	}
3755
3756	// If we are reading an object of class type, there may still be more
3757	// things we need to check: if there are any mutable subobjects, we
3758	// cannot perform this read. (This only happens when performing a trivial
3759	// copy or assignment.)
3760	if (ObjType->isRecordType() &&
3761	!Obj.mayAccessMutableMembers(Info, AK: handler.AccessKind) &&
3762	diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
3763	return handler.failed();
3764	}
3765
3766	if (I == N) {
3767	if (!handler.found(*O, ObjType))
3768	return false;
3769
3770	// If we modified a bit-field, truncate it to the right width.
3771	if (isModification(handler.AccessKind) &&
3772	LastField && LastField->isBitField() &&
3773	!truncateBitfieldValue(Info, E, Value&: *O, FD: LastField))
3774	return false;
3775
3776	return true;
3777	}
3778
3779	LastField = nullptr;
3780	if (ObjType->isArrayType()) {
3781	// Next subobject is an array element.
3782	const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T: ObjType);
3783	assert(CAT && "vla in literal type?");
3784	uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3785	if (CAT->getSize().ule(RHS: Index)) {
3786	// Note, it should not be possible to form a pointer with a valid
3787	// designator which points more than one past the end of the array.
3788	if (Info.getLangOpts().CPlusPlus11)
3789	Info.FFDiag(E, diag::note_constexpr_access_past_end)
3790	<< handler.AccessKind;
3791	else
3792	Info.FFDiag(E);
3793	return handler.failed();
3794	}
3795
3796	ObjType = CAT->getElementType();
3797
3798	if (O->getArrayInitializedElts() > Index)
3799	O = &O->getArrayInitializedElt(I: Index);
3800	else if (!isRead(handler.AccessKind)) {
3801	if (!CheckArraySize(Info, CAT, CallLoc: E->getExprLoc()))
3802	return handler.failed();
3803
3804	expandArray(Array&: *O, Index);
3805	O = &O->getArrayInitializedElt(I: Index);
3806	} else
3807	O = &O->getArrayFiller();
3808	} else if (ObjType->isAnyComplexType()) {
3809	// Next subobject is a complex number.
3810	uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3811	if (Index > 1) {
3812	if (Info.getLangOpts().CPlusPlus11)
3813	Info.FFDiag(E, diag::note_constexpr_access_past_end)
3814	<< handler.AccessKind;
3815	else
3816	Info.FFDiag(E);
3817	return handler.failed();
3818	}
3819
3820	ObjType = getSubobjectType(
3821	ObjType, SubobjType: ObjType->castAs<ComplexType>()->getElementType());
3822
3823	assert(I == N - 1 && "extracting subobject of scalar?");
3824	if (O->isComplexInt()) {
3825	return handler.found(Index ? O->getComplexIntImag()
3826	: O->getComplexIntReal(), ObjType);
3827	} else {
3828	assert(O->isComplexFloat());
3829	return handler.found(Index ? O->getComplexFloatImag()
3830	: O->getComplexFloatReal(), ObjType);
3831	}
3832	} else if (const FieldDecl *Field = getAsField(E: Sub.Entries[I])) {
3833	if (Field->isMutable() &&
3834	!Obj.mayAccessMutableMembers(Info, AK: handler.AccessKind)) {
3835	Info.FFDiag(E, diag::note_constexpr_access_mutable, 1)
3836	<< handler.AccessKind << Field;
3837	Info.Note(Field->getLocation(), diag::note_declared_at);
3838	return handler.failed();
3839	}
3840
3841	// Next subobject is a class, struct or union field.
3842	RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
3843	if (RD->isUnion()) {
3844	const FieldDecl *UnionField = O->getUnionField();
3845	if (!UnionField ||
3846	UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
3847	if (I == N - 1 && handler.AccessKind == AK_Construct) {
3848	// Placement new onto an inactive union member makes it active.
3849	O->setUnion(Field, Value: APValue());
3850	} else {
3851	// FIXME: If O->getUnionValue() is absent, report that there's no
3852	// active union member rather than reporting the prior active union
3853	// member. We'll need to fix nullptr_t to not use APValue() as its
3854	// representation first.
3855	Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
3856	<< handler.AccessKind << Field << !UnionField << UnionField;
3857	return handler.failed();
3858	}
3859	}
3860	O = &O->getUnionValue();
3861	} else
3862	O = &O->getStructField(i: Field->getFieldIndex());
3863
3864	ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable());
3865	LastField = Field;
3866	if (Field->getType().isVolatileQualified())
3867	VolatileField = Field;
3868	} else {
3869	// Next subobject is a base class.
3870	const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
3871	const CXXRecordDecl *Base = getAsBaseClass(E: Sub.Entries[I]);
3872	O = &O->getStructBase(i: getBaseIndex(Derived, Base));
3873
3874	ObjType = getSubobjectType(ObjType, SubobjType: Info.Ctx.getRecordType(Base));
3875	}
3876	}
3877	}
3878
3879	namespace {
3880	struct ExtractSubobjectHandler {
3881	EvalInfo &Info;
3882	const Expr *E;
3883	APValue &Result;
3884	const AccessKinds AccessKind;
3885
3886	typedef bool result_type;
3887	bool failed() { return false; }
3888	bool found(APValue &Subobj, QualType SubobjType) {
3889	Result = Subobj;
3890	if (AccessKind == AK_ReadObjectRepresentation)
3891	return true;
3892	return CheckFullyInitialized(Info, DiagLoc: E->getExprLoc(), Type: SubobjType, Value: Result);
3893	}
3894	bool found(APSInt &Value, QualType SubobjType) {
3895	Result = APValue(Value);
3896	return true;
3897	}
3898	bool found(APFloat &Value, QualType SubobjType) {
3899	Result = APValue(Value);
3900	return true;
3901	}
3902	};
3903	} // end anonymous namespace
3904
3905	/// Extract the designated sub-object of an rvalue.
3906	static bool extractSubobject(EvalInfo &Info, const Expr *E,
3907	const CompleteObject &Obj,
3908	const SubobjectDesignator &Sub, APValue &Result,
3909	AccessKinds AK = AK_Read) {
3910	assert(AK == AK_Read || AK == AK_ReadObjectRepresentation);
3911	ExtractSubobjectHandler Handler = {.Info: Info, .E: E, .Result: Result, .AccessKind: AK};
3912	return findSubobject(Info, E, Obj, Sub, handler&: Handler);
3913	}
3914
3915	namespace {
3916	struct ModifySubobjectHandler {
3917	EvalInfo &Info;
3918	APValue &NewVal;
3919	const Expr *E;
3920
3921	typedef bool result_type;
3922	static const AccessKinds AccessKind = AK_Assign;
3923
3924	bool checkConst(QualType QT) {
3925	// Assigning to a const object has undefined behavior.
3926	if (QT.isConstQualified()) {
3927	Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3928	return false;
3929	}
3930	return true;
3931	}
3932
3933	bool failed() { return false; }
3934	bool found(APValue &Subobj, QualType SubobjType) {
3935	if (!checkConst(QT: SubobjType))
3936	return false;
3937	// We've been given ownership of NewVal, so just swap it in.
3938	Subobj.swap(RHS&: NewVal);
3939	return true;
3940	}
3941	bool found(APSInt &Value, QualType SubobjType) {
3942	if (!checkConst(QT: SubobjType))
3943	return false;
3944	if (!NewVal.isInt()) {
3945	// Maybe trying to write a cast pointer value into a complex?
3946	Info.FFDiag(E);
3947	return false;
3948	}
3949	Value = NewVal.getInt();
3950	return true;
3951	}
3952	bool found(APFloat &Value, QualType SubobjType) {
3953	if (!checkConst(QT: SubobjType))
3954	return false;
3955	Value = NewVal.getFloat();
3956	return true;
3957	}
3958	};
3959	} // end anonymous namespace
3960
3961	const AccessKinds ModifySubobjectHandler::AccessKind;
3962
3963	/// Update the designated sub-object of an rvalue to the given value.
3964	static bool modifySubobject(EvalInfo &Info, const Expr *E,
3965	const CompleteObject &Obj,
3966	const SubobjectDesignator &Sub,
3967	APValue &NewVal) {
3968	ModifySubobjectHandler Handler = { .Info: Info, .NewVal: NewVal, .E: E };
3969	return findSubobject(Info, E, Obj, Sub, handler&: Handler);
3970	}
3971
3972	/// Find the position where two subobject designators diverge, or equivalently
3973	/// the length of the common initial subsequence.
3974	static unsigned FindDesignatorMismatch(QualType ObjType,
3975	const SubobjectDesignator &A,
3976	const SubobjectDesignator &B,
3977	bool &WasArrayIndex) {
3978	unsigned I = 0, N = std::min(a: A.Entries.size(), b: B.Entries.size());
3979	for (/**/; I != N; ++I) {
3980	if (!ObjType.isNull() &&
3981	(ObjType->isArrayType() || ObjType->isAnyComplexType())) {
3982	// Next subobject is an array element.
3983	if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
3984	WasArrayIndex = true;
3985	return I;
3986	}
3987	if (ObjType->isAnyComplexType())
3988	ObjType = ObjType->castAs<ComplexType>()->getElementType();
3989	else
3990	ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
3991	} else {
3992	if (A.Entries[I].getAsBaseOrMember() !=
3993	B.Entries[I].getAsBaseOrMember()) {
3994	WasArrayIndex = false;
3995	return I;
3996	}
3997	if (const FieldDecl *FD = getAsField(E: A.Entries[I]))
3998	// Next subobject is a field.
3999	ObjType = FD->getType();
4000	else
4001	// Next subobject is a base class.
4002	ObjType = QualType();
4003	}
4004	}
4005	WasArrayIndex = false;
4006	return I;
4007	}
4008
4009	/// Determine whether the given subobject designators refer to elements of the
4010	/// same array object.
4011	static bool AreElementsOfSameArray(QualType ObjType,
4012	const SubobjectDesignator &A,
4013	const SubobjectDesignator &B) {
4014	if (A.Entries.size() != B.Entries.size())
4015	return false;
4016
4017	bool IsArray = A.MostDerivedIsArrayElement;
4018	if (IsArray && A.MostDerivedPathLength != A.Entries.size())
4019	// A is a subobject of the array element.
4020	return false;
4021
4022	// If A (and B) designates an array element, the last entry will be the array
4023	// index. That doesn't have to match. Otherwise, we're in the 'implicit array
4024	// of length 1' case, and the entire path must match.
4025	bool WasArrayIndex;
4026	unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
4027	return CommonLength >= A.Entries.size() - IsArray;
4028	}
4029
4030	/// Find the complete object to which an LValue refers.
4031	static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
4032	AccessKinds AK, const LValue &LVal,
4033	QualType LValType) {
4034	if (LVal.InvalidBase) {
4035	Info.FFDiag(E);
4036	return CompleteObject();
4037	}
4038
4039	if (!LVal.Base) {
4040	Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
4041	return CompleteObject();
4042	}
4043
4044	CallStackFrame *Frame = nullptr;
4045	unsigned Depth = 0;
4046	if (LVal.getLValueCallIndex()) {
4047	std::tie(args&: Frame, args&: Depth) =
4048	Info.getCallFrameAndDepth(CallIndex: LVal.getLValueCallIndex());
4049	if (!Frame) {
4050	Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
4051	<< AK << LVal.Base.is<const ValueDecl*>();
4052	NoteLValueLocation(Info, Base: LVal.Base);
4053	return CompleteObject();
4054	}
4055	}
4056
4057	bool IsAccess = isAnyAccess(AK);
4058
4059	// C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
4060	// is not a constant expression (even if the object is non-volatile). We also
4061	// apply this rule to C++98, in order to conform to the expected 'volatile'
4062	// semantics.
4063	if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
4064	if (Info.getLangOpts().CPlusPlus)
4065	Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
4066	<< AK << LValType;
4067	else
4068	Info.FFDiag(E);
4069	return CompleteObject();
4070	}
4071
4072	// Compute value storage location and type of base object.
4073	APValue *BaseVal = nullptr;
4074	QualType BaseType = getType(B: LVal.Base);
4075
4076	if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl &&
4077	lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4078	// This is the object whose initializer we're evaluating, so its lifetime
4079	// started in the current evaluation.
4080	BaseVal = Info.EvaluatingDeclValue;
4081	} else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
4082	// Allow reading from a GUID declaration.
4083	if (auto *GD = dyn_cast<MSGuidDecl>(Val: D)) {
4084	if (isModification(AK)) {
4085	// All the remaining cases do not permit modification of the object.
4086	Info.FFDiag(E, diag::note_constexpr_modify_global);
4087	return CompleteObject();
4088	}
4089	APValue &V = GD->getAsAPValue();
4090	if (V.isAbsent()) {
4091	Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
4092	<< GD->getType();
4093	return CompleteObject();
4094	}
4095	return CompleteObject(LVal.Base, &V, GD->getType());
4096	}
4097
4098	// Allow reading the APValue from an UnnamedGlobalConstantDecl.
4099	if (auto *GCD = dyn_cast<UnnamedGlobalConstantDecl>(Val: D)) {
4100	if (isModification(AK)) {
4101	Info.FFDiag(E, diag::note_constexpr_modify_global);
4102	return CompleteObject();
4103	}
4104	return CompleteObject(LVal.Base, const_cast<APValue *>(&GCD->getValue()),
4105	GCD->getType());
4106	}
4107
4108	// Allow reading from template parameter objects.
4109	if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(Val: D)) {
4110	if (isModification(AK)) {
4111	Info.FFDiag(E, diag::note_constexpr_modify_global);
4112	return CompleteObject();
4113	}
4114	return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()),
4115	TPO->getType());
4116	}
4117
4118	// In C++98, const, non-volatile integers initialized with ICEs are ICEs.
4119	// In C++11, constexpr, non-volatile variables initialized with constant
4120	// expressions are constant expressions too. Inside constexpr functions,
4121	// parameters are constant expressions even if they're non-const.
4122	// In C++1y, objects local to a constant expression (those with a Frame) are
4123	// both readable and writable inside constant expressions.
4124	// In C, such things can also be folded, although they are not ICEs.
4125	const VarDecl *VD = dyn_cast<VarDecl>(Val: D);
4126	if (VD) {
4127	if (const VarDecl *VDef = VD->getDefinition(C&: Info.Ctx))
4128	VD = VDef;
4129	}
4130	if (!VD || VD->isInvalidDecl()) {
4131	Info.FFDiag(E);
4132	return CompleteObject();
4133	}
4134
4135	bool IsConstant = BaseType.isConstant(Ctx: Info.Ctx);
4136	bool ConstexprVar = false;
4137	if (const auto *VD = dyn_cast_if_present<VarDecl>(
4138	Val: Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()))
4139	ConstexprVar = VD->isConstexpr();
4140
4141	// Unless we're looking at a local variable or argument in a constexpr call,
4142	// the variable we're reading must be const.
4143	if (!Frame) {
4144	if (IsAccess && isa<ParmVarDecl>(Val: VD)) {
4145	// Access of a parameter that's not associated with a frame isn't going
4146	// to work out, but we can leave it to evaluateVarDeclInit to provide a
4147	// suitable diagnostic.
4148	} else if (Info.getLangOpts().CPlusPlus14 &&
4149	lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4150	// OK, we can read and modify an object if we're in the process of
4151	// evaluating its initializer, because its lifetime began in this
4152	// evaluation.
4153	} else if (isModification(AK)) {
4154	// All the remaining cases do not permit modification of the object.
4155	Info.FFDiag(E, diag::note_constexpr_modify_global);
4156	return CompleteObject();
4157	} else if (VD->isConstexpr()) {
4158	// OK, we can read this variable.
4159	} else if (Info.getLangOpts().C23 && ConstexprVar) {
4160	Info.FFDiag(E);
4161	return CompleteObject();
4162	} else if (BaseType->isIntegralOrEnumerationType()) {
4163	if (!IsConstant) {
4164	if (!IsAccess)
4165	return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4166	if (Info.getLangOpts().CPlusPlus) {
4167	Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
4168	Info.Note(VD->getLocation(), diag::note_declared_at);
4169	} else {
4170	Info.FFDiag(E);
4171	}
4172	return CompleteObject();
4173	}
4174	} else if (!IsAccess) {
4175	return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4176	} else if (IsConstant && Info.checkingPotentialConstantExpression() &&
4177	BaseType->isLiteralType(Ctx: Info.Ctx) && !VD->hasDefinition()) {
4178	// This variable might end up being constexpr. Don't diagnose it yet.
4179	} else if (IsConstant) {
4180	// Keep evaluating to see what we can do. In particular, we support
4181	// folding of const floating-point types, in order to make static const
4182	// data members of such types (supported as an extension) more useful.
4183	if (Info.getLangOpts().CPlusPlus) {
4184	Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11
4185	? diag::note_constexpr_ltor_non_constexpr
4186	: diag::note_constexpr_ltor_non_integral, 1)
4187	<< VD << BaseType;
4188	Info.Note(VD->getLocation(), diag::note_declared_at);
4189	} else {
4190	Info.CCEDiag(E);
4191	}
4192	} else {
4193	// Never allow reading a non-const value.
4194	if (Info.getLangOpts().CPlusPlus) {
4195	Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
4196	? diag::note_constexpr_ltor_non_constexpr
4197	: diag::note_constexpr_ltor_non_integral, 1)
4198	<< VD << BaseType;
4199	Info.Note(VD->getLocation(), diag::note_declared_at);
4200	} else {
4201	Info.FFDiag(E);
4202	}
4203	return CompleteObject();
4204	}
4205	}
4206
4207	if (!evaluateVarDeclInit(Info, E, VD, Frame, Version: LVal.getLValueVersion(), Result&: BaseVal))
4208	return CompleteObject();
4209	} else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
4210	std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
4211	if (!Alloc) {
4212	Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK;
4213	return CompleteObject();
4214	}
4215	return CompleteObject(LVal.Base, &(*Alloc)->Value,
4216	LVal.Base.getDynamicAllocType());
4217	} else {
4218	const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4219
4220	if (!Frame) {
4221	if (const MaterializeTemporaryExpr *MTE =
4222	dyn_cast_or_null<MaterializeTemporaryExpr>(Val: Base)) {
4223	assert(MTE->getStorageDuration() == SD_Static &&
4224	"should have a frame for a non-global materialized temporary");
4225
4226	// C++20 [expr.const]p4: [DR2126]
4227	// An object or reference is usable in constant expressions if it is
4228	// - a temporary object of non-volatile const-qualified literal type
4229	// whose lifetime is extended to that of a variable that is usable
4230	// in constant expressions
4231	//
4232	// C++20 [expr.const]p5:
4233	// an lvalue-to-rvalue conversion [is not allowed unless it applies to]
4234	// - a non-volatile glvalue that refers to an object that is usable
4235	// in constant expressions, or
4236	// - a non-volatile glvalue of literal type that refers to a
4237	// non-volatile object whose lifetime began within the evaluation
4238	// of E;
4239	//
4240	// C++11 misses the 'began within the evaluation of e' check and
4241	// instead allows all temporaries, including things like:
4242	// int &&r = 1;
4243	// int x = ++r;
4244	// constexpr int k = r;
4245	// Therefore we use the C++14-onwards rules in C++11 too.
4246	//
4247	// Note that temporaries whose lifetimes began while evaluating a
4248	// variable's constructor are not usable while evaluating the
4249	// corresponding destructor, not even if they're of const-qualified
4250	// types.
4251	if (!MTE->isUsableInConstantExpressions(Context: Info.Ctx) &&
4252	!lifetimeStartedInEvaluation(Info, Base: LVal.Base)) {
4253	if (!IsAccess)
4254	return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4255	Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
4256	Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
4257	return CompleteObject();
4258	}
4259
4260	BaseVal = MTE->getOrCreateValue(MayCreate: false);
4261	assert(BaseVal && "got reference to unevaluated temporary");
4262	} else {
4263	if (!IsAccess)
4264	return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4265	APValue Val;
4266	LVal.moveInto(V&: Val);
4267	Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
4268	<< AK
4269	<< Val.getAsString(Info.Ctx,
4270	Info.Ctx.getLValueReferenceType(LValType));
4271	NoteLValueLocation(Info, Base: LVal.Base);
4272	return CompleteObject();
4273	}
4274	} else {
4275	BaseVal = Frame->getTemporary(Key: Base, Version: LVal.Base.getVersion());
4276	assert(BaseVal && "missing value for temporary");
4277	}
4278	}
4279
4280	// In C++14, we can't safely access any mutable state when we might be
4281	// evaluating after an unmodeled side effect. Parameters are modeled as state
4282	// in the caller, but aren't visible once the call returns, so they can be
4283	// modified in a speculatively-evaluated call.
4284	//
4285	// FIXME: Not all local state is mutable. Allow local constant subobjects
4286	// to be read here (but take care with 'mutable' fields).
4287	unsigned VisibleDepth = Depth;
4288	if (llvm::isa_and_nonnull<ParmVarDecl>(
4289	Val: LVal.Base.dyn_cast<const ValueDecl *>()))
4290	++VisibleDepth;
4291	if ((Frame && Info.getLangOpts().CPlusPlus14 &&
4292	Info.EvalStatus.HasSideEffects) ||
4293	(isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth))
4294	return CompleteObject();
4295
4296	return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
4297	}
4298
4299	/// Perform an lvalue-to-rvalue conversion on the given glvalue. This
4300	/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
4301	/// glvalue referred to by an entity of reference type.
4302	///
4303	/// \param Info - Information about the ongoing evaluation.
4304	/// \param Conv - The expression for which we are performing the conversion.
4305	/// Used for diagnostics.
4306	/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
4307	/// case of a non-class type).
4308	/// \param LVal - The glvalue on which we are attempting to perform this action.
4309	/// \param RVal - The produced value will be placed here.
4310	/// \param WantObjectRepresentation - If true, we're looking for the object
4311	/// representation rather than the value, and in particular,
4312	/// there is no requirement that the result be fully initialized.
4313	static bool
4314	handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
4315	const LValue &LVal, APValue &RVal,
4316	bool WantObjectRepresentation = false) {
4317	if (LVal.Designator.Invalid)
4318	return false;
4319
4320	// Check for special cases where there is no existing APValue to look at.
4321	const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4322
4323	AccessKinds AK =
4324	WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;
4325
4326	if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
4327	if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Val: Base)) {
4328	// In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
4329	// initializer until now for such expressions. Such an expression can't be
4330	// an ICE in C, so this only matters for fold.
4331	if (Type.isVolatileQualified()) {
4332	Info.FFDiag(E: Conv);
4333	return false;
4334	}
4335
4336	APValue Lit;
4337	if (!Evaluate(Result&: Lit, Info, E: CLE->getInitializer()))
4338	return false;
4339
4340	// According to GCC info page:
4341	//
4342	// 6.28 Compound Literals
4343	//
4344	// As an optimization, G++ sometimes gives array compound literals longer
4345	// lifetimes: when the array either appears outside a function or has a
4346	// const-qualified type. If foo and its initializer had elements of type
4347	// char *const rather than char *, or if foo were a global variable, the
4348	// array would have static storage duration. But it is probably safest
4349	// just to avoid the use of array compound literals in C++ code.
4350	//
4351	// Obey that rule by checking constness for converted array types.
4352
4353	QualType CLETy = CLE->getType();
4354	if (CLETy->isArrayType() && !Type->isArrayType()) {
4355	if (!CLETy.isConstant(Ctx: Info.Ctx)) {
4356	Info.FFDiag(E: Conv);
4357	Info.Note(CLE->getExprLoc(), diag::note_declared_at);
4358	return false;
4359	}
4360	}
4361
4362	CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
4363	return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK);
4364	} else if (isa<StringLiteral>(Val: Base) || isa<PredefinedExpr>(Val: Base)) {
4365	// Special-case character extraction so we don't have to construct an
4366	// APValue for the whole string.
4367	assert(LVal.Designator.Entries.size() <= 1 &&
4368	"Can only read characters from string literals");
4369	if (LVal.Designator.Entries.empty()) {
4370	// Fail for now for LValue to RValue conversion of an array.
4371	// (This shouldn't show up in C/C++, but it could be triggered by a
4372	// weird EvaluateAsRValue call from a tool.)
4373	Info.FFDiag(E: Conv);
4374	return false;
4375	}
4376	if (LVal.Designator.isOnePastTheEnd()) {
4377	if (Info.getLangOpts().CPlusPlus11)
4378	Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK;
4379	else
4380	Info.FFDiag(E: Conv);
4381	return false;
4382	}
4383	uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
4384	RVal = APValue(extractStringLiteralCharacter(Info, Lit: Base, Index: CharIndex));
4385	return true;
4386	}
4387	}
4388
4389	CompleteObject Obj = findCompleteObject(Info, E: Conv, AK, LVal, LValType: Type);
4390	return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK);
4391	}
4392
4393	/// Perform an assignment of Val to LVal. Takes ownership of Val.
4394	static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
4395	QualType LValType, APValue &Val) {
4396	if (LVal.Designator.Invalid)
4397	return false;
4398
4399	if (!Info.getLangOpts().CPlusPlus14) {
4400	Info.FFDiag(E);
4401	return false;
4402	}
4403
4404	CompleteObject Obj = findCompleteObject(Info, E, AK: AK_Assign, LVal, LValType);
4405	return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
4406	}
4407
4408	namespace {
4409	struct CompoundAssignSubobjectHandler {
4410	EvalInfo &Info;
4411	const CompoundAssignOperator *E;
4412	QualType PromotedLHSType;
4413	BinaryOperatorKind Opcode;
4414	const APValue &RHS;
4415
4416	static const AccessKinds AccessKind = AK_Assign;
4417
4418	typedef bool result_type;
4419
4420	bool checkConst(QualType QT) {
4421	// Assigning to a const object has undefined behavior.
4422	if (QT.isConstQualified()) {
4423	Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4424	return false;
4425	}
4426	return true;
4427	}
4428
4429	bool failed() { return false; }
4430	bool found(APValue &Subobj, QualType SubobjType) {
4431	switch (Subobj.getKind()) {
4432	case APValue::Int:
4433	return found(Value&: Subobj.getInt(), SubobjType);
4434	case APValue::Float:
4435	return found(Value&: Subobj.getFloat(), SubobjType);
4436	case APValue::ComplexInt:
4437	case APValue::ComplexFloat:
4438	// FIXME: Implement complex compound assignment.
4439	Info.FFDiag(E);
4440	return false;
4441	case APValue::LValue:
4442	return foundPointer(Subobj, SubobjType);
4443	case APValue::Vector:
4444	return foundVector(Value&: Subobj, SubobjType);
4445	case APValue::Indeterminate:
4446	Info.FFDiag(E, diag::note_constexpr_access_uninit)
4447	<< /*read of=*/0 << /*uninitialized object=*/1
4448	<< E->getLHS()->getSourceRange();
4449	return false;
4450	default:
4451	// FIXME: can this happen?
4452	Info.FFDiag(E);
4453	return false;
4454	}
4455	}
4456
4457	bool foundVector(APValue &Value, QualType SubobjType) {
4458	if (!checkConst(QT: SubobjType))
4459	return false;
4460
4461	if (!SubobjType->isVectorType()) {
4462	Info.FFDiag(E);
4463	return false;
4464	}
4465	return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS);
4466	}
4467
4468	bool found(APSInt &Value, QualType SubobjType) {
4469	if (!checkConst(QT: SubobjType))
4470	return false;
4471
4472	if (!SubobjType->isIntegerType()) {
4473	// We don't support compound assignment on integer-cast-to-pointer
4474	// values.
4475	Info.FFDiag(E);
4476	return false;
4477	}
4478
4479	if (RHS.isInt()) {
4480	APSInt LHS =
4481	HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value);
4482	if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
4483	return false;
4484	Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
4485	return true;
4486	} else if (RHS.isFloat()) {
4487	const FPOptions FPO = E->getFPFeaturesInEffect(
4488	Info.Ctx.getLangOpts());
4489	APFloat FValue(0.0);
4490	return HandleIntToFloatCast(Info, E, FPO, SubobjType, Value,
4491	PromotedLHSType, FValue) &&
4492	handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) &&
4493	HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType,
4494	Value);
4495	}
4496
4497	Info.FFDiag(E);
4498	return false;
4499	}
4500	bool found(APFloat &Value, QualType SubobjType) {
4501	return checkConst(SubobjType) &&
4502	HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
4503	Value) &&
4504	handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
4505	HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
4506	}
4507	bool foundPointer(APValue &Subobj, QualType SubobjType) {
4508	if (!checkConst(QT: SubobjType))
4509	return false;
4510
4511	QualType PointeeType;
4512	if (const PointerType *PT = SubobjType->getAs<PointerType>())
4513	PointeeType = PT->getPointeeType();
4514
4515	if (PointeeType.isNull() || !RHS.isInt() ||
4516	(Opcode != BO_Add && Opcode != BO_Sub)) {
4517	Info.FFDiag(E);
4518	return false;
4519	}
4520
4521	APSInt Offset = RHS.getInt();
4522	if (Opcode == BO_Sub)
4523	negateAsSigned(Int&: Offset);
4524
4525	LValue LVal;
4526	LVal.setFrom(Ctx&: Info.Ctx, V: Subobj);
4527	if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
4528	return false;
4529	LVal.moveInto(V&: Subobj);
4530	return true;
4531	}
4532	};
4533	} // end anonymous namespace
4534
4535	const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
4536
4537	/// Perform a compound assignment of LVal <op>= RVal.
4538	static bool handleCompoundAssignment(EvalInfo &Info,
4539	const CompoundAssignOperator *E,
4540	const LValue &LVal, QualType LValType,
4541	QualType PromotedLValType,
4542	BinaryOperatorKind Opcode,
4543	const APValue &RVal) {
4544	if (LVal.Designator.Invalid)
4545	return false;
4546
4547	if (!Info.getLangOpts().CPlusPlus14) {
4548	Info.FFDiag(E);
4549	return false;
4550	}
4551
4552	CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4553	CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
4554	RVal };
4555	return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4556	}
4557
4558	namespace {
4559	struct IncDecSubobjectHandler {
4560	EvalInfo &Info;
4561	const UnaryOperator *E;
4562	AccessKinds AccessKind;
4563	APValue *Old;
4564
4565	typedef bool result_type;
4566
4567	bool checkConst(QualType QT) {
4568	// Assigning to a const object has undefined behavior.
4569	if (QT.isConstQualified()) {
4570	Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4571	return false;
4572	}
4573	return true;
4574	}
4575
4576	bool failed() { return false; }
4577	bool found(APValue &Subobj, QualType SubobjType) {
4578	// Stash the old value. Also clear Old, so we don't clobber it later
4579	// if we're post-incrementing a complex.
4580	if (Old) {
4581	*Old = Subobj;
4582	Old = nullptr;
4583	}
4584
4585	switch (Subobj.getKind()) {
4586	case APValue::Int:
4587	return found(Value&: Subobj.getInt(), SubobjType);
4588	case APValue::Float:
4589	return found(Value&: Subobj.getFloat(), SubobjType);
4590	case APValue::ComplexInt:
4591	return found(Value&: Subobj.getComplexIntReal(),
4592	SubobjType: SubobjType->castAs<ComplexType>()->getElementType()
4593	.withCVRQualifiers(CVR: SubobjType.getCVRQualifiers()));
4594	case APValue::ComplexFloat:
4595	return found(Value&: Subobj.getComplexFloatReal(),
4596	SubobjType: SubobjType->castAs<ComplexType>()->getElementType()
4597	.withCVRQualifiers(CVR: SubobjType.getCVRQualifiers()));
4598	case APValue::LValue:
4599	return foundPointer(Subobj, SubobjType);
4600	default:
4601	// FIXME: can this happen?
4602	Info.FFDiag(E);
4603	return false;
4604	}
4605	}
4606	bool found(APSInt &Value, QualType SubobjType) {
4607	if (!checkConst(QT: SubobjType))
4608	return false;
4609
4610	if (!SubobjType->isIntegerType()) {
4611	// We don't support increment / decrement on integer-cast-to-pointer
4612	// values.
4613	Info.FFDiag(E);
4614	return false;
4615	}
4616
4617	if (Old) *Old = APValue(Value);
4618
4619	// bool arithmetic promotes to int, and the conversion back to bool
4620	// doesn't reduce mod 2^n, so special-case it.
4621	if (SubobjType->isBooleanType()) {
4622	if (AccessKind == AK_Increment)
4623	Value = 1;
4624	else
4625	Value = !Value;
4626	return true;
4627	}
4628
4629	bool WasNegative = Value.isNegative();
4630	if (AccessKind == AK_Increment) {
4631	++Value;
4632
4633	if (!WasNegative && Value.isNegative() && E->canOverflow()) {
4634	APSInt ActualValue(Value, /*IsUnsigned*/true);
4635	return HandleOverflow(Info, E, ActualValue, SubobjType);
4636	}
4637	} else {
4638	--Value;
4639
4640	if (WasNegative && !Value.isNegative() && E->canOverflow()) {
4641	unsigned BitWidth = Value.getBitWidth();
4642	APSInt ActualValue(Value.sext(width: BitWidth + 1), /*IsUnsigned*/false);
4643	ActualValue.setBit(BitWidth);
4644	return HandleOverflow(Info, E, ActualValue, SubobjType);
4645	}
4646	}
4647	return true;
4648	}
4649	bool found(APFloat &Value, QualType SubobjType) {
4650	if (!checkConst(QT: SubobjType))
4651	return false;
4652
4653	if (Old) *Old = APValue(Value);
4654
4655	APFloat One(Value.getSemantics(), 1);
4656	llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
4657	APFloat::opStatus St;
4658	if (AccessKind == AK_Increment)
4659	St = Value.add(RHS: One, RM);
4660	else
4661	St = Value.subtract(RHS: One, RM);
4662	return checkFloatingPointResult(Info, E, St);
4663	}
4664	bool foundPointer(APValue &Subobj, QualType SubobjType) {
4665	if (!checkConst(QT: SubobjType))
4666	return false;
4667
4668	QualType PointeeType;
4669	if (const PointerType *PT = SubobjType->getAs<PointerType>())
4670	PointeeType = PT->getPointeeType();
4671	else {
4672	Info.FFDiag(E);
4673	return false;
4674	}
4675
4676	LValue LVal;
4677	LVal.setFrom(Ctx&: Info.Ctx, V: Subobj);
4678	if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
4679	AccessKind == AK_Increment ? 1 : -1))
4680	return false;
4681	LVal.moveInto(V&: Subobj);
4682	return true;
4683	}
4684	};
4685	} // end anonymous namespace
4686
4687	/// Perform an increment or decrement on LVal.
4688	static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
4689	QualType LValType, bool IsIncrement, APValue *Old) {
4690	if (LVal.Designator.Invalid)
4691	return false;
4692
4693	if (!Info.getLangOpts().CPlusPlus14) {
4694	Info.FFDiag(E);
4695	return false;
4696	}
4697
4698	AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
4699	CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
4700	IncDecSubobjectHandler Handler = {.Info: Info, .E: cast<UnaryOperator>(Val: E), .AccessKind: AK, .Old: Old};
4701	return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4702	}
4703
4704	/// Build an lvalue for the object argument of a member function call.
4705	static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
4706	LValue &This) {
4707	if (Object->getType()->isPointerType() && Object->isPRValue())
4708	return EvaluatePointer(E: Object, Result&: This, Info);
4709
4710	if (Object->isGLValue())
4711	return EvaluateLValue(E: Object, Result&: This, Info);
4712
4713	if (Object->getType()->isLiteralType(Ctx: Info.Ctx))
4714	return EvaluateTemporary(E: Object, Result&: This, Info);
4715
4716	if (Object->getType()->isRecordType() && Object->isPRValue())
4717	return EvaluateTemporary(E: Object, Result&: This, Info);
4718
4719	Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
4720	return false;
4721	}
4722
4723	/// HandleMemberPointerAccess - Evaluate a member access operation and build an
4724	/// lvalue referring to the result.
4725	///
4726	/// \param Info - Information about the ongoing evaluation.
4727	/// \param LV - An lvalue referring to the base of the member pointer.
4728	/// \param RHS - The member pointer expression.
4729	/// \param IncludeMember - Specifies whether the member itself is included in
4730	/// the resulting LValue subobject designator. This is not possible when
4731	/// creating a bound member function.
4732	/// \return The field or method declaration to which the member pointer refers,
4733	/// or 0 if evaluation fails.
4734	static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4735	QualType LVType,
4736	LValue &LV,
4737	const Expr *RHS,
4738	bool IncludeMember = true) {
4739	MemberPtr MemPtr;
4740	if (!EvaluateMemberPointer(E: RHS, Result&: MemPtr, Info))
4741	return nullptr;
4742
4743	// C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
4744	// member value, the behavior is undefined.
4745	if (!MemPtr.getDecl()) {
4746	// FIXME: Specific diagnostic.
4747	Info.FFDiag(E: RHS);
4748	return nullptr;
4749	}
4750
4751	if (MemPtr.isDerivedMember()) {
4752	// This is a member of some derived class. Truncate LV appropriately.
4753	// The end of the derived-to-base path for the base object must match the
4754	// derived-to-base path for the member pointer.
4755	if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
4756	LV.Designator.Entries.size()) {
4757	Info.FFDiag(E: RHS);
4758	return nullptr;
4759	}
4760	unsigned PathLengthToMember =
4761	LV.Designator.Entries.size() - MemPtr.Path.size();
4762	for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
4763	const CXXRecordDecl *LVDecl = getAsBaseClass(
4764	LV.Designator.Entries[PathLengthToMember + I]);
4765	const CXXRecordDecl *MPDecl = MemPtr.Path[I];
4766	if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
4767	Info.FFDiag(E: RHS);
4768	return nullptr;
4769	}
4770	}
4771
4772	// Truncate the lvalue to the appropriate derived class.
4773	if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
4774	PathLengthToMember))
4775	return nullptr;
4776	} else if (!MemPtr.Path.empty()) {
4777	// Extend the LValue path with the member pointer's path.
4778	LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
4779	MemPtr.Path.size() + IncludeMember);
4780
4781	// Walk down to the appropriate base class.
4782	if (const PointerType *PT = LVType->getAs<PointerType>())
4783	LVType = PT->getPointeeType();
4784	const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
4785	assert(RD && "member pointer access on non-class-type expression");
4786	// The first class in the path is that of the lvalue.
4787	for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
4788	const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
4789	if (!HandleLValueDirectBase(Info, E: RHS, Obj&: LV, Derived: RD, Base))
4790	return nullptr;
4791	RD = Base;
4792	}
4793	// Finally cast to the class containing the member.
4794	if (!HandleLValueDirectBase(Info, E: RHS, Obj&: LV, Derived: RD,
4795	Base: MemPtr.getContainingRecord()))
4796	return nullptr;
4797	}
4798
4799	// Add the member. Note that we cannot build bound member functions here.
4800	if (IncludeMember) {
4801	if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: MemPtr.getDecl())) {
4802	if (!HandleLValueMember(Info, E: RHS, LVal&: LV, FD))
4803	return nullptr;
4804	} else if (const IndirectFieldDecl *IFD =
4805	dyn_cast<IndirectFieldDecl>(Val: MemPtr.getDecl())) {
4806	if (!HandleLValueIndirectMember(Info, E: RHS, LVal&: LV, IFD))
4807	return nullptr;
4808	} else {
4809	llvm_unreachable("can't construct reference to bound member function");
4810	}
4811	}
4812
4813	return MemPtr.getDecl();
4814	}
4815
4816	static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4817	const BinaryOperator *BO,
4818	LValue &LV,
4819	bool IncludeMember = true) {
4820	assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
4821
4822	if (!EvaluateObjectArgument(Info, Object: BO->getLHS(), This&: LV)) {
4823	if (Info.noteFailure()) {
4824	MemberPtr MemPtr;
4825	EvaluateMemberPointer(E: BO->getRHS(), Result&: MemPtr, Info);
4826	}
4827	return nullptr;
4828	}
4829
4830	return HandleMemberPointerAccess(Info, LVType: BO->getLHS()->getType(), LV,
4831	RHS: BO->getRHS(), IncludeMember);
4832	}
4833
4834	/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
4835	/// the provided lvalue, which currently refers to the base object.
4836	static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
4837	LValue &Result) {
4838	SubobjectDesignator &D = Result.Designator;
4839	if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
4840	return false;
4841
4842	QualType TargetQT = E->getType();
4843	if (const PointerType *PT = TargetQT->getAs<PointerType>())
4844	TargetQT = PT->getPointeeType();
4845
4846	// Check this cast lands within the final derived-to-base subobject path.
4847	if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
4848	Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4849	<< D.MostDerivedType << TargetQT;
4850	return false;
4851	}
4852
4853	// Check the type of the final cast. We don't need to check the path,
4854	// since a cast can only be formed if the path is unique.
4855	unsigned NewEntriesSize = D.Entries.size() - E->path_size();
4856	const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
4857	const CXXRecordDecl *FinalType;
4858	if (NewEntriesSize == D.MostDerivedPathLength)
4859	FinalType = D.MostDerivedType->getAsCXXRecordDecl();
4860	else
4861	FinalType = getAsBaseClass(E: D.Entries[NewEntriesSize - 1]);
4862	if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
4863	Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4864	<< D.MostDerivedType << TargetQT;
4865	return false;
4866	}
4867
4868	// Truncate the lvalue to the appropriate derived class.
4869	return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
4870	}
4871
4872	/// Get the value to use for a default-initialized object of type T.
4873	/// Return false if it encounters something invalid.
4874	static bool handleDefaultInitValue(QualType T, APValue &Result) {
4875	bool Success = true;
4876
4877	// If there is already a value present don't overwrite it.
4878	if (!Result.isAbsent())
4879	return true;
4880
4881	if (auto *RD = T->getAsCXXRecordDecl()) {
4882	if (RD->isInvalidDecl()) {
4883	Result = APValue();
4884	return false;
4885	}
4886	if (RD->isUnion()) {
4887	Result = APValue((const FieldDecl *)nullptr);
4888	return true;
4889	}
4890	Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4891	std::distance(RD->field_begin(), RD->field_end()));
4892
4893	unsigned Index = 0;
4894	for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
4895	End = RD->bases_end();
4896	I != End; ++I, ++Index)
4897	Success &=
4898	handleDefaultInitValue(T: I->getType(), Result&: Result.getStructBase(i: Index));
4899
4900	for (const auto *I : RD->fields()) {
4901	if (I->isUnnamedBitField())
4902	continue;
4903	Success &= handleDefaultInitValue(
4904	I->getType(), Result.getStructField(I->getFieldIndex()));
4905	}
4906	return Success;
4907	}
4908
4909	if (auto *AT =
4910	dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) {
4911	Result = APValue(APValue::UninitArray(), 0, AT->getZExtSize());
4912	if (Result.hasArrayFiller())
4913	Success &=
4914	handleDefaultInitValue(AT->getElementType(), Result.getArrayFiller());
4915
4916	return Success;
4917	}
4918
4919	Result = APValue::IndeterminateValue();
4920	return true;
4921	}
4922
4923	namespace {
4924	enum EvalStmtResult {
4925	/// Evaluation failed.
4926	ESR_Failed,
4927	/// Hit a 'return' statement.
4928	ESR_Returned,
4929	/// Evaluation succeeded.
4930	ESR_Succeeded,
4931	/// Hit a 'continue' statement.
4932	ESR_Continue,
4933	/// Hit a 'break' statement.
4934	ESR_Break,
4935	/// Still scanning for 'case' or 'default' statement.
4936	ESR_CaseNotFound
4937	};
4938	}
4939
4940	static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
4941	if (VD->isInvalidDecl())
4942	return false;
4943	// We don't need to evaluate the initializer for a static local.
4944	if (!VD->hasLocalStorage())
4945	return true;
4946
4947	LValue Result;
4948	APValue &Val = Info.CurrentCall->createTemporary(VD, VD->getType(),
4949	ScopeKind::Block, Result);
4950
4951	const Expr *InitE = VD->getInit();
4952	if (!InitE) {
4953	if (VD->getType()->isDependentType())
4954	return Info.noteSideEffect();
4955	return handleDefaultInitValue(VD->getType(), Val);
4956	}
4957	if (InitE->isValueDependent())
4958	return false;
4959
4960	if (!EvaluateInPlace(Result&: Val, Info, This: Result, E: InitE)) {
4961	// Wipe out any partially-computed value, to allow tracking that this
4962	// evaluation failed.
4963	Val = APValue();
4964	return false;
4965	}
4966
4967	return true;
4968	}
4969
4970	static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
4971	bool OK = true;
4972
4973	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
4974	OK &= EvaluateVarDecl(Info, VD);
4975
4976	if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(Val: D))
4977	for (auto *BD : DD->bindings())
4978	if (auto *VD = BD->getHoldingVar())
4979	OK &= EvaluateDecl(Info, VD);
4980
4981	return OK;
4982	}
4983
4984	static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) {
4985	assert(E->isValueDependent());
4986	if (Info.noteSideEffect())
4987	return true;
4988	assert(E->containsErrors() && "valid value-dependent expression should never "
4989	"reach invalid code path.");
4990	return false;
4991	}
4992
4993	/// Evaluate a condition (either a variable declaration or an expression).
4994	static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
4995	const Expr *Cond, bool &Result) {
4996	if (Cond->isValueDependent())
4997	return false;
4998	FullExpressionRAII Scope(Info);
4999	if (CondDecl && !EvaluateDecl(Info, CondDecl))
5000	return false;
5001	if (!EvaluateAsBooleanCondition(E: Cond, Result, Info))
5002	return false;
5003	return Scope.destroy();
5004	}
5005
5006	namespace {
5007	/// A location where the result (returned value) of evaluating a
5008	/// statement should be stored.
5009	struct StmtResult {
5010	/// The APValue that should be filled in with the returned value.
5011	APValue &Value;
5012	/// The location containing the result, if any (used to support RVO).
5013	const LValue *Slot;
5014	};
5015
5016	struct TempVersionRAII {
5017	CallStackFrame &Frame;
5018
5019	TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
5020	Frame.pushTempVersion();
5021	}
5022
5023	~TempVersionRAII() {
5024	Frame.popTempVersion();
5025	}
5026	};
5027
5028	}
5029
5030	static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
5031	const Stmt *S,
5032	const SwitchCase *SC = nullptr);
5033
5034	/// Evaluate the body of a loop, and translate the result as appropriate.
5035	static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
5036	const Stmt *Body,
5037	const SwitchCase *Case = nullptr) {
5038	BlockScopeRAII Scope(Info);
5039
5040	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Body, SC: Case);
5041	if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
5042	ESR = ESR_Failed;
5043
5044	switch (ESR) {
5045	case ESR_Break:
5046	return ESR_Succeeded;
5047	case ESR_Succeeded:
5048	case ESR_Continue:
5049	return ESR_Continue;
5050	case ESR_Failed:
5051	case ESR_Returned:
5052	case ESR_CaseNotFound:
5053	return ESR;
5054	}
5055	llvm_unreachable("Invalid EvalStmtResult!");
5056	}
5057
5058	/// Evaluate a switch statement.
5059	static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
5060	const SwitchStmt *SS) {
5061	BlockScopeRAII Scope(Info);
5062
5063	// Evaluate the switch condition.
5064	APSInt Value;
5065	{
5066	if (const Stmt *Init = SS->getInit()) {
5067	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init);
5068	if (ESR != ESR_Succeeded) {
5069	if (ESR != ESR_Failed && !Scope.destroy())
5070	ESR = ESR_Failed;
5071	return ESR;
5072	}
5073	}
5074
5075	FullExpressionRAII CondScope(Info);
5076	if (SS->getConditionVariable() &&
5077	!EvaluateDecl(Info, SS->getConditionVariable()))
5078	return ESR_Failed;
5079	if (SS->getCond()->isValueDependent()) {
5080	// We don't know what the value is, and which branch should jump to.
5081	EvaluateDependentExpr(E: SS->getCond(), Info);
5082	return ESR_Failed;
5083	}
5084	if (!EvaluateInteger(E: SS->getCond(), Result&: Value, Info))
5085	return ESR_Failed;
5086
5087	if (!CondScope.destroy())
5088	return ESR_Failed;
5089	}
5090
5091	// Find the switch case corresponding to the value of the condition.
5092	// FIXME: Cache this lookup.
5093	const SwitchCase *Found = nullptr;
5094	for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
5095	SC = SC->getNextSwitchCase()) {
5096	if (isa<DefaultStmt>(Val: SC)) {
5097	Found = SC;
5098	continue;
5099	}
5100
5101	const CaseStmt *CS = cast<CaseStmt>(Val: SC);
5102	APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Ctx: Info.Ctx);
5103	APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Ctx: Info.Ctx)
5104	: LHS;
5105	if (LHS <= Value && Value <= RHS) {
5106	Found = SC;
5107	break;
5108	}
5109	}
5110
5111	if (!Found)
5112	return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5113
5114	// Search the switch body for the switch case and evaluate it from there.
5115	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: SS->getBody(), SC: Found);
5116	if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
5117	return ESR_Failed;
5118
5119	switch (ESR) {
5120	case ESR_Break:
5121	return ESR_Succeeded;
5122	case ESR_Succeeded:
5123	case ESR_Continue:
5124	case ESR_Failed:
5125	case ESR_Returned:
5126	return ESR;
5127	case ESR_CaseNotFound:
5128	// This can only happen if the switch case is nested within a statement
5129	// expression. We have no intention of supporting that.
5130	Info.FFDiag(Found->getBeginLoc(),
5131	diag::note_constexpr_stmt_expr_unsupported);
5132	return ESR_Failed;
5133	}
5134	llvm_unreachable("Invalid EvalStmtResult!");
5135	}
5136
5137	static bool CheckLocalVariableDeclaration(EvalInfo &Info, const VarDecl *VD) {
5138	// An expression E is a core constant expression unless the evaluation of E
5139	// would evaluate one of the following: [C++23] - a control flow that passes
5140	// through a declaration of a variable with static or thread storage duration
5141	// unless that variable is usable in constant expressions.
5142	if (VD->isLocalVarDecl() && VD->isStaticLocal() &&
5143	!VD->isUsableInConstantExpressions(C: Info.Ctx)) {
5144	Info.CCEDiag(VD->getLocation(), diag::note_constexpr_static_local)
5145	<< (VD->getTSCSpec() == TSCS_unspecified ? 0 : 1) << VD;
5146	return false;
5147	}
5148	return true;
5149	}
5150
5151	// Evaluate a statement.
5152	static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
5153	const Stmt *S, const SwitchCase *Case) {
5154	if (!Info.nextStep(S))
5155	return ESR_Failed;
5156
5157	// If we're hunting down a 'case' or 'default' label, recurse through
5158	// substatements until we hit the label.
5159	if (Case) {
5160	switch (S->getStmtClass()) {
5161	case Stmt::CompoundStmtClass:
5162	// FIXME: Precompute which substatement of a compound statement we
5163	// would jump to, and go straight there rather than performing a
5164	// linear scan each time.
5165	case Stmt::LabelStmtClass:
5166	case Stmt::AttributedStmtClass:
5167	case Stmt::DoStmtClass:
5168	break;
5169
5170	case Stmt::CaseStmtClass:
5171	case Stmt::DefaultStmtClass:
5172	if (Case == S)
5173	Case = nullptr;
5174	break;
5175
5176	case Stmt::IfStmtClass: {
5177	// FIXME: Precompute which side of an 'if' we would jump to, and go
5178	// straight there rather than scanning both sides.
5179	const IfStmt *IS = cast<IfStmt>(Val: S);
5180
5181	// Wrap the evaluation in a block scope, in case it's a DeclStmt
5182	// preceded by our switch label.
5183	BlockScopeRAII Scope(Info);
5184
5185	// Step into the init statement in case it brings an (uninitialized)
5186	// variable into scope.
5187	if (const Stmt *Init = IS->getInit()) {
5188	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init, Case);
5189	if (ESR != ESR_CaseNotFound) {
5190	assert(ESR != ESR_Succeeded);
5191	return ESR;
5192	}
5193	}
5194
5195	// Condition variable must be initialized if it exists.
5196	// FIXME: We can skip evaluating the body if there's a condition
5197	// variable, as there can't be any case labels within it.
5198	// (The same is true for 'for' statements.)
5199
5200	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: IS->getThen(), Case);
5201	if (ESR == ESR_Failed)
5202	return ESR;
5203	if (ESR != ESR_CaseNotFound)
5204	return Scope.destroy() ? ESR : ESR_Failed;
5205	if (!IS->getElse())
5206	return ESR_CaseNotFound;
5207
5208	ESR = EvaluateStmt(Result, Info, S: IS->getElse(), Case);
5209	if (ESR == ESR_Failed)
5210	return ESR;
5211	if (ESR != ESR_CaseNotFound)
5212	return Scope.destroy() ? ESR : ESR_Failed;
5213	return ESR_CaseNotFound;
5214	}
5215
5216	case Stmt::WhileStmtClass: {
5217	EvalStmtResult ESR =
5218	EvaluateLoopBody(Result, Info, Body: cast<WhileStmt>(Val: S)->getBody(), Case);
5219	if (ESR != ESR_Continue)
5220	return ESR;
5221	break;
5222	}
5223
5224	case Stmt::ForStmtClass: {
5225	const ForStmt *FS = cast<ForStmt>(Val: S);
5226	BlockScopeRAII Scope(Info);
5227
5228	// Step into the init statement in case it brings an (uninitialized)
5229	// variable into scope.
5230	if (const Stmt *Init = FS->getInit()) {
5231	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init, Case);
5232	if (ESR != ESR_CaseNotFound) {
5233	assert(ESR != ESR_Succeeded);
5234	return ESR;
5235	}
5236	}
5237
5238	EvalStmtResult ESR =
5239	EvaluateLoopBody(Result, Info, Body: FS->getBody(), Case);
5240	if (ESR != ESR_Continue)
5241	return ESR;
5242	if (const auto *Inc = FS->getInc()) {
5243	if (Inc->isValueDependent()) {
5244	if (!EvaluateDependentExpr(E: Inc, Info))
5245	return ESR_Failed;
5246	} else {
5247	FullExpressionRAII IncScope(Info);
5248	if (!EvaluateIgnoredValue(Info, E: Inc) || !IncScope.destroy())
5249	return ESR_Failed;
5250	}
5251	}
5252	break;
5253	}
5254
5255	case Stmt::DeclStmtClass: {
5256	// Start the lifetime of any uninitialized variables we encounter. They
5257	// might be used by the selected branch of the switch.
5258	const DeclStmt *DS = cast<DeclStmt>(Val: S);
5259	for (const auto *D : DS->decls()) {
5260	if (const auto *VD = dyn_cast<VarDecl>(Val: D)) {
5261	if (!CheckLocalVariableDeclaration(Info, VD))
5262	return ESR_Failed;
5263	if (VD->hasLocalStorage() && !VD->getInit())
5264	if (!EvaluateVarDecl(Info, VD))
5265	return ESR_Failed;
5266	// FIXME: If the variable has initialization that can't be jumped
5267	// over, bail out of any immediately-surrounding compound-statement
5268	// too. There can't be any case labels here.
5269	}
5270	}
5271	return ESR_CaseNotFound;
5272	}
5273
5274	default:
5275	return ESR_CaseNotFound;
5276	}
5277	}
5278
5279	switch (S->getStmtClass()) {
5280	default:
5281	if (const Expr *E = dyn_cast<Expr>(Val: S)) {
5282	if (E->isValueDependent()) {
5283	if (!EvaluateDependentExpr(E, Info))
5284	return ESR_Failed;
5285	} else {
5286	// Don't bother evaluating beyond an expression-statement which couldn't
5287	// be evaluated.
5288	// FIXME: Do we need the FullExpressionRAII object here?
5289	// VisitExprWithCleanups should create one when necessary.
5290	FullExpressionRAII Scope(Info);
5291	if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
5292	return ESR_Failed;
5293	}
5294	return ESR_Succeeded;
5295	}
5296
5297	Info.FFDiag(Loc: S->getBeginLoc()) << S->getSourceRange();
5298	return ESR_Failed;
5299
5300	case Stmt::NullStmtClass:
5301	return ESR_Succeeded;
5302
5303	case Stmt::DeclStmtClass: {
5304	const DeclStmt *DS = cast<DeclStmt>(Val: S);
5305	for (const auto *D : DS->decls()) {
5306	const VarDecl *VD = dyn_cast_or_null<VarDecl>(Val: D);
5307	if (VD && !CheckLocalVariableDeclaration(Info, VD))
5308	return ESR_Failed;
5309	// Each declaration initialization is its own full-expression.
5310	FullExpressionRAII Scope(Info);
5311	if (!EvaluateDecl(Info, D) && !Info.noteFailure())
5312	return ESR_Failed;
5313	if (!Scope.destroy())
5314	return ESR_Failed;
5315	}
5316	return ESR_Succeeded;
5317	}
5318
5319	case Stmt::ReturnStmtClass: {
5320	const Expr *RetExpr = cast<ReturnStmt>(Val: S)->getRetValue();
5321	FullExpressionRAII Scope(Info);
5322	if (RetExpr && RetExpr->isValueDependent()) {
5323	EvaluateDependentExpr(E: RetExpr, Info);
5324	// We know we returned, but we don't know what the value is.
5325	return ESR_Failed;
5326	}
5327	if (RetExpr &&
5328	!(Result.Slot
5329	? EvaluateInPlace(Result&: Result.Value, Info, This: *Result.Slot, E: RetExpr)
5330	: Evaluate(Result&: Result.Value, Info, E: RetExpr)))
5331	return ESR_Failed;
5332	return Scope.destroy() ? ESR_Returned : ESR_Failed;
5333	}
5334
5335	case Stmt::CompoundStmtClass: {
5336	BlockScopeRAII Scope(Info);
5337
5338	const CompoundStmt *CS = cast<CompoundStmt>(Val: S);
5339	for (const auto *BI : CS->body()) {
5340	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: BI, Case);
5341	if (ESR == ESR_Succeeded)
5342	Case = nullptr;
5343	else if (ESR != ESR_CaseNotFound) {
5344	if (ESR != ESR_Failed && !Scope.destroy())
5345	return ESR_Failed;
5346	return ESR;
5347	}
5348	}
5349	if (Case)
5350	return ESR_CaseNotFound;
5351	return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5352	}
5353
5354	case Stmt::IfStmtClass: {
5355	const IfStmt *IS = cast<IfStmt>(Val: S);
5356
5357	// Evaluate the condition, as either a var decl or as an expression.
5358	BlockScopeRAII Scope(Info);
5359	if (const Stmt *Init = IS->getInit()) {
5360	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: Init);
5361	if (ESR != ESR_Succeeded) {
5362	if (ESR != ESR_Failed && !Scope.destroy())
5363	return ESR_Failed;
5364	return ESR;
5365	}
5366	}
5367	bool Cond;
5368	if (IS->isConsteval()) {
5369	Cond = IS->isNonNegatedConsteval();
5370	// If we are not in a constant context, if consteval should not evaluate
5371	// to true.
5372	if (!Info.InConstantContext)
5373	Cond = !Cond;
5374	} else if (!EvaluateCond(Info, CondDecl: IS->getConditionVariable(), Cond: IS->getCond(),
5375	Result&: Cond))
5376	return ESR_Failed;
5377
5378	if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
5379	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: SubStmt);
5380	if (ESR != ESR_Succeeded) {
5381	if (ESR != ESR_Failed && !Scope.destroy())
5382	return ESR_Failed;
5383	return ESR;
5384	}
5385	}
5386	return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5387	}
5388
5389	case Stmt::WhileStmtClass: {
5390	const WhileStmt *WS = cast<WhileStmt>(Val: S);
5391	while (true) {
5392	BlockScopeRAII Scope(Info);
5393	bool Continue;
5394	if (!EvaluateCond(Info, CondDecl: WS->getConditionVariable(), Cond: WS->getCond(),
5395	Result&: Continue))
5396	return ESR_Failed;
5397	if (!Continue)
5398	break;
5399
5400	EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: WS->getBody());
5401	if (ESR != ESR_Continue) {
5402	if (ESR != ESR_Failed && !Scope.destroy())
5403	return ESR_Failed;
5404	return ESR;
5405	}
5406	if (!Scope.destroy())
5407	return ESR_Failed;
5408	}
5409	return ESR_Succeeded;
5410	}
5411
5412	case Stmt::DoStmtClass: {
5413	const DoStmt *DS = cast<DoStmt>(Val: S);
5414	bool Continue;
5415	do {
5416	EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: DS->getBody(), Case);
5417	if (ESR != ESR_Continue)
5418	return ESR;
5419	Case = nullptr;
5420
5421	if (DS->getCond()->isValueDependent()) {
5422	EvaluateDependentExpr(E: DS->getCond(), Info);
5423	// Bailout as we don't know whether to keep going or terminate the loop.
5424	return ESR_Failed;
5425	}
5426	FullExpressionRAII CondScope(Info);
5427	if (!EvaluateAsBooleanCondition(E: DS->getCond(), Result&: Continue, Info) ||
5428	!CondScope.destroy())
5429	return ESR_Failed;
5430	} while (Continue);
5431	return ESR_Succeeded;
5432	}
5433
5434	case Stmt::ForStmtClass: {
5435	const ForStmt *FS = cast<ForStmt>(Val: S);
5436	BlockScopeRAII ForScope(Info);
5437	if (FS->getInit()) {
5438	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getInit());
5439	if (ESR != ESR_Succeeded) {
5440	if (ESR != ESR_Failed && !ForScope.destroy())
5441	return ESR_Failed;
5442	return ESR;
5443	}
5444	}
5445	while (true) {
5446	BlockScopeRAII IterScope(Info);
5447	bool Continue = true;
5448	if (FS->getCond() && !EvaluateCond(Info, CondDecl: FS->getConditionVariable(),
5449	Cond: FS->getCond(), Result&: Continue))
5450	return ESR_Failed;
5451	if (!Continue)
5452	break;
5453
5454	EvalStmtResult ESR = EvaluateLoopBody(Result, Info, Body: FS->getBody());
5455	if (ESR != ESR_Continue) {
5456	if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
5457	return ESR_Failed;
5458	return ESR;
5459	}
5460
5461	if (const auto *Inc = FS->getInc()) {
5462	if (Inc->isValueDependent()) {
5463	if (!EvaluateDependentExpr(E: Inc, Info))
5464	return ESR_Failed;
5465	} else {
5466	FullExpressionRAII IncScope(Info);
5467	if (!EvaluateIgnoredValue(Info, E: Inc) || !IncScope.destroy())
5468	return ESR_Failed;
5469	}
5470	}
5471
5472	if (!IterScope.destroy())
5473	return ESR_Failed;
5474	}
5475	return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
5476	}
5477
5478	case Stmt::CXXForRangeStmtClass: {
5479	const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(Val: S);
5480	BlockScopeRAII Scope(Info);
5481
5482	// Evaluate the init-statement if present.
5483	if (FS->getInit()) {
5484	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getInit());
5485	if (ESR != ESR_Succeeded) {
5486	if (ESR != ESR_Failed && !Scope.destroy())
5487	return ESR_Failed;
5488	return ESR;
5489	}
5490	}
5491
5492	// Initialize the __range variable.
5493	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: FS->getRangeStmt());
5494	if (ESR != ESR_Succeeded) {
5495	if (ESR != ESR_Failed && !Scope.destroy())
5496	return ESR_Failed;
5497	return ESR;
5498	}
5499
5500	// In error-recovery cases it's possible to get here even if we failed to
5501	// synthesize the __begin and __end variables.
5502	if (!FS->getBeginStmt() || !FS->getEndStmt() || !FS->getCond())
5503	return ESR_Failed;
5504
5505	// Create the __begin and __end iterators.
5506	ESR = EvaluateStmt(Result, Info, S: FS->getBeginStmt());
5507	if (ESR != ESR_Succeeded) {
5508	if (ESR != ESR_Failed && !Scope.destroy())
5509	return ESR_Failed;
5510	return ESR;
5511	}
5512	ESR = EvaluateStmt(Result, Info, S: FS->getEndStmt());
5513	if (ESR != ESR_Succeeded) {
5514	if (ESR != ESR_Failed && !Scope.destroy())
5515	return ESR_Failed;
5516	return ESR;
5517	}
5518
5519	while (true) {
5520	// Condition: __begin != __end.
5521	{
5522	if (FS->getCond()->isValueDependent()) {
5523	EvaluateDependentExpr(E: FS->getCond(), Info);
5524	// We don't know whether to keep going or terminate the loop.
5525	return ESR_Failed;
5526	}
5527	bool Continue = true;
5528	FullExpressionRAII CondExpr(Info);
5529	if (!EvaluateAsBooleanCondition(E: FS->getCond(), Result&: Continue, Info))
5530	return ESR_Failed;
5531	if (!Continue)
5532	break;
5533	}
5534
5535	// User's variable declaration, initialized by *__begin.
5536	BlockScopeRAII InnerScope(Info);
5537	ESR = EvaluateStmt(Result, Info, S: FS->getLoopVarStmt());
5538	if (ESR != ESR_Succeeded) {
5539	if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5540	return ESR_Failed;
5541	return ESR;
5542	}
5543
5544	// Loop body.
5545	ESR = EvaluateLoopBody(Result, Info, Body: FS->getBody());
5546	if (ESR != ESR_Continue) {
5547	if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5548	return ESR_Failed;
5549	return ESR;
5550	}
5551	if (FS->getInc()->isValueDependent()) {
5552	if (!EvaluateDependentExpr(E: FS->getInc(), Info))
5553	return ESR_Failed;
5554	} else {
5555	// Increment: ++__begin
5556	if (!EvaluateIgnoredValue(Info, E: FS->getInc()))
5557	return ESR_Failed;
5558	}
5559
5560	if (!InnerScope.destroy())
5561	return ESR_Failed;
5562	}
5563
5564	return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5565	}
5566
5567	case Stmt::SwitchStmtClass:
5568	return EvaluateSwitch(Result, Info, SS: cast<SwitchStmt>(Val: S));
5569
5570	case Stmt::ContinueStmtClass:
5571	return ESR_Continue;
5572
5573	case Stmt::BreakStmtClass:
5574	return ESR_Break;
5575
5576	case Stmt::LabelStmtClass:
5577	return EvaluateStmt(Result, Info, S: cast<LabelStmt>(Val: S)->getSubStmt(), Case);
5578
5579	case Stmt::AttributedStmtClass: {
5580	const auto *AS = cast<AttributedStmt>(Val: S);
5581	const auto *SS = AS->getSubStmt();
5582	MSConstexprContextRAII ConstexprContext(
5583	*Info.CurrentCall, hasSpecificAttr<MSConstexprAttr>(AS->getAttrs()) &&
5584	isa<ReturnStmt>(SS));
5585
5586	auto LO = Info.getCtx().getLangOpts();
5587	if (LO.CXXAssumptions && !LO.MSVCCompat) {
5588	for (auto *Attr : AS->getAttrs()) {
5589	auto *AA = dyn_cast<CXXAssumeAttr>(Attr);
5590	if (!AA)
5591	continue;
5592
5593	auto *Assumption = AA->getAssumption();
5594	if (Assumption->isValueDependent())
5595	return ESR_Failed;
5596
5597	if (Assumption->HasSideEffects(Info.getCtx()))
5598	continue;
5599
5600	bool Value;
5601	if (!EvaluateAsBooleanCondition(Assumption, Value, Info))
5602	return ESR_Failed;
5603	if (!Value) {
5604	Info.CCEDiag(Assumption->getExprLoc(),
5605	diag::note_constexpr_assumption_failed);
5606	return ESR_Failed;
5607	}
5608	}
5609	}
5610
5611	return EvaluateStmt(Result, Info, S: SS, Case);
5612	}
5613
5614	case Stmt::CaseStmtClass:
5615	case Stmt::DefaultStmtClass:
5616	return EvaluateStmt(Result, Info, S: cast<SwitchCase>(Val: S)->getSubStmt(), Case);
5617	case Stmt::CXXTryStmtClass:
5618	// Evaluate try blocks by evaluating all sub statements.
5619	return EvaluateStmt(Result, Info, cast<CXXTryStmt>(Val: S)->getTryBlock(), Case);
5620	}
5621	}
5622
5623	/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5624	/// default constructor. If so, we'll fold it whether or not it's marked as
5625	/// constexpr. If it is marked as constexpr, we will never implicitly define it,
5626	/// so we need special handling.
5627	static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
5628	const CXXConstructorDecl *CD,
5629	bool IsValueInitialization) {
5630	if (!CD->isTrivial() || !CD->isDefaultConstructor())
5631	return false;
5632
5633	// Value-initialization does not call a trivial default constructor, so such a
5634	// call is a core constant expression whether or not the constructor is
5635	// constexpr.
5636	if (!CD->isConstexpr() && !IsValueInitialization) {
5637	if (Info.getLangOpts().CPlusPlus11) {
5638	// FIXME: If DiagDecl is an implicitly-declared special member function,
5639	// we should be much more explicit about why it's not constexpr.
5640	Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
5641	<< /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
5642	Info.Note(CD->getLocation(), diag::note_declared_at);
5643	} else {
5644	Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
5645	}
5646	}
5647	return true;
5648	}
5649
5650	/// CheckConstexprFunction - Check that a function can be called in a constant
5651	/// expression.
5652	static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
5653	const FunctionDecl *Declaration,
5654	const FunctionDecl *Definition,
5655	const Stmt *Body) {
5656	// Potential constant expressions can contain calls to declared, but not yet
5657	// defined, constexpr functions.
5658	if (Info.checkingPotentialConstantExpression() && !Definition &&
5659	Declaration->isConstexpr())
5660	return false;
5661
5662	// Bail out if the function declaration itself is invalid. We will
5663	// have produced a relevant diagnostic while parsing it, so just
5664	// note the problematic sub-expression.
5665	if (Declaration->isInvalidDecl()) {
5666	Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5667	return false;
5668	}
5669
5670	// DR1872: An instantiated virtual constexpr function can't be called in a
5671	// constant expression (prior to C++20). We can still constant-fold such a
5672	// call.
5673	if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) &&
5674	cast<CXXMethodDecl>(Declaration)->isVirtual())
5675	Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call);
5676
5677	if (Definition && Definition->isInvalidDecl()) {
5678	Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5679	return false;
5680	}
5681
5682	// Can we evaluate this function call?
5683	if (Definition && Body &&
5684	(Definition->isConstexpr() || (Info.CurrentCall->CanEvalMSConstexpr &&
5685	Definition->hasAttr<MSConstexprAttr>())))
5686	return true;
5687
5688	if (Info.getLangOpts().CPlusPlus11) {
5689	const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
5690
5691	// If this function is not constexpr because it is an inherited
5692	// non-constexpr constructor, diagnose that directly.
5693	auto *CD = dyn_cast<CXXConstructorDecl>(Val: DiagDecl);
5694	if (CD && CD->isInheritingConstructor()) {
5695	auto *Inherited = CD->getInheritedConstructor().getConstructor();
5696	if (!Inherited->isConstexpr())
5697	DiagDecl = CD = Inherited;
5698	}
5699
5700	// FIXME: If DiagDecl is an implicitly-declared special member function
5701	// or an inheriting constructor, we should be much more explicit about why
5702	// it's not constexpr.
5703	if (CD && CD->isInheritingConstructor())
5704	Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
5705	<< CD->getInheritedConstructor().getConstructor()->getParent();
5706	else
5707	Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
5708	<< DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
5709	Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
5710	} else {
5711	Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5712	}
5713	return false;
5714	}
5715
5716	namespace {
5717	struct CheckDynamicTypeHandler {
5718	AccessKinds AccessKind;
5719	typedef bool result_type;
5720	bool failed() { return false; }
5721	bool found(APValue &Subobj, QualType SubobjType) { return true; }
5722	bool found(APSInt &Value, QualType SubobjType) { return true; }
5723	bool found(APFloat &Value, QualType SubobjType) { return true; }
5724	};
5725	} // end anonymous namespace
5726
5727	/// Check that we can access the notional vptr of an object / determine its
5728	/// dynamic type.
5729	static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
5730	AccessKinds AK, bool Polymorphic) {
5731	if (This.Designator.Invalid)
5732	return false;
5733
5734	CompleteObject Obj = findCompleteObject(Info, E, AK, LVal: This, LValType: QualType());
5735
5736	if (!Obj)
5737	return false;
5738
5739	if (!Obj.Value) {
5740	// The object is not usable in constant expressions, so we can't inspect
5741	// its value to see if it's in-lifetime or what the active union members
5742	// are. We can still check for a one-past-the-end lvalue.
5743	if (This.Designator.isOnePastTheEnd() ||
5744	This.Designator.isMostDerivedAnUnsizedArray()) {
5745	Info.FFDiag(E, This.Designator.isOnePastTheEnd()
5746	? diag::note_constexpr_access_past_end
5747	: diag::note_constexpr_access_unsized_array)
5748	<< AK;
5749	return false;
5750	} else if (Polymorphic) {
5751	// Conservatively refuse to perform a polymorphic operation if we would
5752	// not be able to read a notional 'vptr' value.
5753	APValue Val;
5754	This.moveInto(V&: Val);
5755	QualType StarThisType =
5756	Info.Ctx.getLValueReferenceType(T: This.Designator.getType(Info.Ctx));
5757	Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type)
5758	<< AK << Val.getAsString(Info.Ctx, StarThisType);
5759	return false;
5760	}
5761	return true;
5762	}
5763
5764	CheckDynamicTypeHandler Handler{.AccessKind: AK};
5765	return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
5766	}
5767
5768	/// Check that the pointee of the 'this' pointer in a member function call is
5769	/// either within its lifetime or in its period of construction or destruction.
5770	static bool
5771	checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
5772	const LValue &This,
5773	const CXXMethodDecl *NamedMember) {
5774	return checkDynamicType(
5775	Info, E, This,
5776	AK: isa<CXXDestructorDecl>(Val: NamedMember) ? AK_Destroy : AK_MemberCall, Polymorphic: false);
5777	}
5778
5779	struct DynamicType {
5780	/// The dynamic class type of the object.
5781	const CXXRecordDecl *Type;
5782	/// The corresponding path length in the lvalue.
5783	unsigned PathLength;
5784	};
5785
5786	static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
5787	unsigned PathLength) {
5788	assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=
5789	Designator.Entries.size() && "invalid path length");
5790	return (PathLength == Designator.MostDerivedPathLength)
5791	? Designator.MostDerivedType->getAsCXXRecordDecl()
5792	: getAsBaseClass(E: Designator.Entries[PathLength - 1]);
5793	}
5794
5795	/// Determine the dynamic type of an object.
5796	static std::optional<DynamicType> ComputeDynamicType(EvalInfo &Info,
5797	const Expr *E,
5798	LValue &This,
5799	AccessKinds AK) {
5800	// If we don't have an lvalue denoting an object of class type, there is no
5801	// meaningful dynamic type. (We consider objects of non-class type to have no
5802	// dynamic type.)
5803	if (!checkDynamicType(Info, E, This, AK, Polymorphic: true))
5804	return std::nullopt;
5805
5806	// Refuse to compute a dynamic type in the presence of virtual bases. This
5807	// shouldn't happen other than in constant-folding situations, since literal
5808	// types can't have virtual bases.
5809	//
5810	// Note that consumers of DynamicType assume that the type has no virtual
5811	// bases, and will need modifications if this restriction is relaxed.
5812	const CXXRecordDecl *Class =
5813	This.Designator.MostDerivedType->getAsCXXRecordDecl();
5814	if (!Class || Class->getNumVBases()) {
5815	Info.FFDiag(E);
5816	return std::nullopt;
5817	}
5818
5819	// FIXME: For very deep class hierarchies, it might be beneficial to use a
5820	// binary search here instead. But the overwhelmingly common case is that
5821	// we're not in the middle of a constructor, so it probably doesn't matter
5822	// in practice.
5823	ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
5824	for (unsigned PathLength = This.Designator.MostDerivedPathLength;
5825	PathLength <= Path.size(); ++PathLength) {
5826	switch (Info.isEvaluatingCtorDtor(Base: This.getLValueBase(),
5827	Path: Path.slice(N: 0, M: PathLength))) {
5828	case ConstructionPhase::Bases:
5829	case ConstructionPhase::DestroyingBases:
5830	// We're constructing or destroying a base class. This is not the dynamic
5831	// type.
5832	break;
5833
5834	case ConstructionPhase::None:
5835	case ConstructionPhase::AfterBases:
5836	case ConstructionPhase::AfterFields:
5837	case ConstructionPhase::Destroying:
5838	// We've finished constructing the base classes and not yet started
5839	// destroying them again, so this is the dynamic type.
5840	return DynamicType{getBaseClassType(This.Designator, PathLength),
5841	PathLength};
5842	}
5843	}
5844
5845	// CWG issue 1517: we're constructing a base class of the object described by
5846	// 'This', so that object has not yet begun its period of construction and
5847	// any polymorphic operation on it results in undefined behavior.
5848	Info.FFDiag(E);
5849	return std::nullopt;
5850	}
5851
5852	/// Perform virtual dispatch.
5853	static const CXXMethodDecl *HandleVirtualDispatch(
5854	EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
5855	llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
5856	std::optional<DynamicType> DynType = ComputeDynamicType(
5857	Info, E, This,
5858	AK: isa<CXXDestructorDecl>(Val: Found) ? AK_Destroy : AK_MemberCall);
5859	if (!DynType)
5860	return nullptr;
5861
5862	// Find the final overrider. It must be declared in one of the classes on the
5863	// path from the dynamic type to the static type.
5864	// FIXME: If we ever allow literal types to have virtual base classes, that
5865	// won't be true.
5866	const CXXMethodDecl *Callee = Found;
5867	unsigned PathLength = DynType->PathLength;
5868	for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
5869	const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength);
5870	const CXXMethodDecl *Overrider =
5871	Found->getCorrespondingMethodDeclaredInClass(RD: Class, MayBeBase: false);
5872	if (Overrider) {
5873	Callee = Overrider;
5874	break;
5875	}
5876	}
5877
5878	// C++2a [class.abstract]p6:
5879	// the effect of making a virtual call to a pure virtual function [...] is
5880	// undefined
5881	if (Callee->isPureVirtual()) {
5882	Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee;
5883	Info.Note(Callee->getLocation(), diag::note_declared_at);
5884	return nullptr;
5885	}
5886
5887	// If necessary, walk the rest of the path to determine the sequence of
5888	// covariant adjustment steps to apply.
5889	if (!Info.Ctx.hasSameUnqualifiedType(T1: Callee->getReturnType(),
5890	T2: Found->getReturnType())) {
5891	CovariantAdjustmentPath.push_back(Elt: Callee->getReturnType());
5892	for (unsigned CovariantPathLength = PathLength + 1;
5893	CovariantPathLength != This.Designator.Entries.size();
5894	++CovariantPathLength) {
5895	const CXXRecordDecl *NextClass =
5896	getBaseClassType(This.Designator, CovariantPathLength);
5897	const CXXMethodDecl *Next =
5898	Found->getCorrespondingMethodDeclaredInClass(RD: NextClass, MayBeBase: false);
5899	if (Next && !Info.Ctx.hasSameUnqualifiedType(
5900	T1: Next->getReturnType(), T2: CovariantAdjustmentPath.back()))
5901	CovariantAdjustmentPath.push_back(Elt: Next->getReturnType());
5902	}
5903	if (!Info.Ctx.hasSameUnqualifiedType(T1: Found->getReturnType(),
5904	T2: CovariantAdjustmentPath.back()))
5905	CovariantAdjustmentPath.push_back(Elt: Found->getReturnType());
5906	}
5907
5908	// Perform 'this' adjustment.
5909	if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength))
5910	return nullptr;
5911
5912	return Callee;
5913	}
5914
5915	/// Perform the adjustment from a value returned by a virtual function to
5916	/// a value of the statically expected type, which may be a pointer or
5917	/// reference to a base class of the returned type.
5918	static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
5919	APValue &Result,
5920	ArrayRef<QualType> Path) {
5921	assert(Result.isLValue() &&
5922	"unexpected kind of APValue for covariant return");
5923	if (Result.isNullPointer())
5924	return true;
5925
5926	LValue LVal;
5927	LVal.setFrom(Ctx&: Info.Ctx, V: Result);
5928
5929	const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
5930	for (unsigned I = 1; I != Path.size(); ++I) {
5931	const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
5932	assert(OldClass && NewClass && "unexpected kind of covariant return");
5933	if (OldClass != NewClass &&
5934	!CastToBaseClass(Info, E, Result&: LVal, DerivedRD: OldClass, BaseRD: NewClass))
5935	return false;
5936	OldClass = NewClass;
5937	}
5938
5939	LVal.moveInto(V&: Result);
5940	return true;
5941	}
5942
5943	/// Determine whether \p Base, which is known to be a direct base class of
5944	/// \p Derived, is a public base class.
5945	static bool isBaseClassPublic(const CXXRecordDecl *Derived,
5946	const CXXRecordDecl *Base) {
5947	for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
5948	auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
5949	if (BaseClass && declaresSameEntity(BaseClass, Base))
5950	return BaseSpec.getAccessSpecifier() == AS_public;
5951	}
5952	llvm_unreachable("Base is not a direct base of Derived");
5953	}
5954
5955	/// Apply the given dynamic cast operation on the provided lvalue.
5956	///
5957	/// This implements the hard case of dynamic_cast, requiring a "runtime check"
5958	/// to find a suitable target subobject.
5959	static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
5960	LValue &Ptr) {
5961	// We can't do anything with a non-symbolic pointer value.
5962	SubobjectDesignator &D = Ptr.Designator;
5963	if (D.Invalid)
5964	return false;
5965
5966	// C++ [expr.dynamic.cast]p6:
5967	// If v is a null pointer value, the result is a null pointer value.
5968	if (Ptr.isNullPointer() && !E->isGLValue())
5969	return true;
5970
5971	// For all the other cases, we need the pointer to point to an object within
5972	// its lifetime / period of construction / destruction, and we need to know
5973	// its dynamic type.
5974	std::optional<DynamicType> DynType =
5975	ComputeDynamicType(Info, E, Ptr, AK_DynamicCast);
5976	if (!DynType)
5977	return false;
5978
5979	// C++ [expr.dynamic.cast]p7:
5980	// If T is "pointer to cv void", then the result is a pointer to the most
5981	// derived object
5982	if (E->getType()->isVoidPointerType())
5983	return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength);
5984
5985	const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
5986	assert(C && "dynamic_cast target is not void pointer nor class");
5987	CanQualType CQT = Info.Ctx.getCanonicalType(T: Info.Ctx.getRecordType(C));
5988
5989	auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
5990	// C++ [expr.dynamic.cast]p9:
5991	if (!E->isGLValue()) {
5992	// The value of a failed cast to pointer type is the null pointer value
5993	// of the required result type.
5994	Ptr.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
5995	return true;
5996	}
5997
5998	// A failed cast to reference type throws [...] std::bad_cast.
5999	unsigned DiagKind;
6000	if (!Paths && (declaresSameEntity(DynType->Type, C) ||
6001	DynType->Type->isDerivedFrom(Base: C)))
6002	DiagKind = 0;
6003	else if (!Paths || Paths->begin() == Paths->end())
6004	DiagKind = 1;
6005	else if (Paths->isAmbiguous(BaseType: CQT))
6006	DiagKind = 2;
6007	else {
6008	assert(Paths->front().Access != AS_public && "why did the cast fail?");
6009	DiagKind = 3;
6010	}
6011	Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed)
6012	<< DiagKind << Ptr.Designator.getType(Info.Ctx)
6013	<< Info.Ctx.getRecordType(DynType->Type)
6014	<< E->getType().getUnqualifiedType();
6015	return false;
6016	};
6017
6018	// Runtime check, phase 1:
6019	// Walk from the base subobject towards the derived object looking for the
6020	// target type.
6021	for (int PathLength = Ptr.Designator.Entries.size();
6022	PathLength >= (int)DynType->PathLength; --PathLength) {
6023	const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength);
6024	if (declaresSameEntity(Class, C))
6025	return CastToDerivedClass(Info, E, Ptr, Class, PathLength);
6026	// We can only walk across public inheritance edges.
6027	if (PathLength > (int)DynType->PathLength &&
6028	!isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1),
6029	Class))
6030	return RuntimeCheckFailed(nullptr);
6031	}
6032
6033	// Runtime check, phase 2:
6034	// Search the dynamic type for an unambiguous public base of type C.
6035	CXXBasePaths Paths(/*FindAmbiguities=*/true,
6036	/*RecordPaths=*/true, /*DetectVirtual=*/false);
6037	if (DynType->Type->isDerivedFrom(Base: C, Paths) && !Paths.isAmbiguous(BaseType: CQT) &&
6038	Paths.front().Access == AS_public) {
6039	// Downcast to the dynamic type...
6040	if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength))
6041	return false;
6042	// ... then upcast to the chosen base class subobject.
6043	for (CXXBasePathElement &Elem : Paths.front())
6044	if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base))
6045	return false;
6046	return true;
6047	}
6048
6049	// Otherwise, the runtime check fails.
6050	return RuntimeCheckFailed(&Paths);
6051	}
6052
6053	namespace {
6054	struct StartLifetimeOfUnionMemberHandler {
6055	EvalInfo &Info;
6056	const Expr *LHSExpr;
6057	const FieldDecl *Field;
6058	bool DuringInit;
6059	bool Failed = false;
6060	static const AccessKinds AccessKind = AK_Assign;
6061
6062	typedef bool result_type;
6063	bool failed() { return Failed; }
6064	bool found(APValue &Subobj, QualType SubobjType) {
6065	// We are supposed to perform no initialization but begin the lifetime of
6066	// the object. We interpret that as meaning to do what default
6067	// initialization of the object would do if all constructors involved were
6068	// trivial:
6069	// * All base, non-variant member, and array element subobjects' lifetimes
6070	// begin
6071	// * No variant members' lifetimes begin
6072	// * All scalar subobjects whose lifetimes begin have indeterminate values
6073	assert(SubobjType->isUnionType());
6074	if (declaresSameEntity(Subobj.getUnionField(), Field)) {
6075	// This union member is already active. If it's also in-lifetime, there's
6076	// nothing to do.
6077	if (Subobj.getUnionValue().hasValue())
6078	return true;
6079	} else if (DuringInit) {
6080	// We're currently in the process of initializing a different union
6081	// member. If we carried on, that initialization would attempt to
6082	// store to an inactive union member, resulting in undefined behavior.
6083	Info.FFDiag(LHSExpr,
6084	diag::note_constexpr_union_member_change_during_init);
6085	return false;
6086	}
6087	APValue Result;
6088	Failed = !handleDefaultInitValue(Field->getType(), Result);
6089	Subobj.setUnion(Field, Value: Result);
6090	return true;
6091	}
6092	bool found(APSInt &Value, QualType SubobjType) {
6093	llvm_unreachable("wrong value kind for union object");
6094	}
6095	bool found(APFloat &Value, QualType SubobjType) {
6096	llvm_unreachable("wrong value kind for union object");
6097	}
6098	};
6099	} // end anonymous namespace
6100
6101	const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;
6102
6103	/// Handle a builtin simple-assignment or a call to a trivial assignment
6104	/// operator whose left-hand side might involve a union member access. If it
6105	/// does, implicitly start the lifetime of any accessed union elements per
6106	/// C++20 [class.union]5.
6107	static bool MaybeHandleUnionActiveMemberChange(EvalInfo &Info,
6108	const Expr *LHSExpr,
6109	const LValue &LHS) {
6110	if (LHS.InvalidBase || LHS.Designator.Invalid)
6111	return false;
6112
6113	llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
6114	// C++ [class.union]p5:
6115	// define the set S(E) of subexpressions of E as follows:
6116	unsigned PathLength = LHS.Designator.Entries.size();
6117	for (const Expr *E = LHSExpr; E != nullptr;) {
6118	// -- If E is of the form A.B, S(E) contains the elements of S(A)...
6119	if (auto *ME = dyn_cast<MemberExpr>(Val: E)) {
6120	auto *FD = dyn_cast<FieldDecl>(Val: ME->getMemberDecl());
6121	// Note that we can't implicitly start the lifetime of a reference,
6122	// so we don't need to proceed any further if we reach one.
6123	if (!FD || FD->getType()->isReferenceType())
6124	break;
6125
6126	// ... and also contains A.B if B names a union member ...
6127	if (FD->getParent()->isUnion()) {
6128	// ... of a non-class, non-array type, or of a class type with a
6129	// trivial default constructor that is not deleted, or an array of
6130	// such types.
6131	auto *RD =
6132	FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
6133	if (!RD || RD->hasTrivialDefaultConstructor())
6134	UnionPathLengths.push_back(Elt: {PathLength - 1, FD});
6135	}
6136
6137	E = ME->getBase();
6138	--PathLength;
6139	assert(declaresSameEntity(FD,
6140	LHS.Designator.Entries[PathLength]
6141	.getAsBaseOrMember().getPointer()));
6142
6143	// -- If E is of the form A[B] and is interpreted as a built-in array
6144	// subscripting operator, S(E) is [S(the array operand, if any)].
6145	} else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(Val: E)) {
6146	// Step over an ArrayToPointerDecay implicit cast.
6147	auto *Base = ASE->getBase()->IgnoreImplicit();
6148	if (!Base->getType()->isArrayType())
6149	break;
6150
6151	E = Base;
6152	--PathLength;
6153
6154	} else if (auto *ICE = dyn_cast<ImplicitCastExpr>(Val: E)) {
6155	// Step over a derived-to-base conversion.
6156	E = ICE->getSubExpr();
6157	if (ICE->getCastKind() == CK_NoOp)
6158	continue;
6159	if (ICE->getCastKind() != CK_DerivedToBase &&
6160	ICE->getCastKind() != CK_UncheckedDerivedToBase)
6161	break;
6162	// Walk path backwards as we walk up from the base to the derived class.
6163	for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
6164	if (Elt->isVirtual()) {
6165	// A class with virtual base classes never has a trivial default
6166	// constructor, so S(E) is empty in this case.
6167	E = nullptr;
6168	break;
6169	}
6170
6171	--PathLength;
6172	assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
6173	LHS.Designator.Entries[PathLength]
6174	.getAsBaseOrMember().getPointer()));
6175	}
6176
6177	// -- Otherwise, S(E) is empty.
6178	} else {
6179	break;
6180	}
6181	}
6182
6183	// Common case: no unions' lifetimes are started.
6184	if (UnionPathLengths.empty())
6185	return true;
6186
6187	// if modification of X [would access an inactive union member], an object
6188	// of the type of X is implicitly created
6189	CompleteObject Obj =
6190	findCompleteObject(Info, E: LHSExpr, AK: AK_Assign, LVal: LHS, LValType: LHSExpr->getType());
6191	if (!Obj)
6192	return false;
6193	for (std::pair<unsigned, const FieldDecl *> LengthAndField :
6194	llvm::reverse(C&: UnionPathLengths)) {
6195	// Form a designator for the union object.
6196	SubobjectDesignator D = LHS.Designator;
6197	D.truncate(Ctx&: Info.Ctx, Base: LHS.Base, NewLength: LengthAndField.first);
6198
6199	bool DuringInit = Info.isEvaluatingCtorDtor(Base: LHS.Base, Path: D.Entries) ==
6200	ConstructionPhase::AfterBases;
6201	StartLifetimeOfUnionMemberHandler StartLifetime{
6202	.Info: Info, .LHSExpr: LHSExpr, .Field: LengthAndField.second, .DuringInit: DuringInit};
6203	if (!findSubobject(Info, E: LHSExpr, Obj, Sub: D, handler&: StartLifetime))
6204	return false;
6205	}
6206
6207	return true;
6208	}
6209
6210	static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg,
6211	CallRef Call, EvalInfo &Info,
6212	bool NonNull = false) {
6213	LValue LV;
6214	// Create the parameter slot and register its destruction. For a vararg
6215	// argument, create a temporary.
6216	// FIXME: For calling conventions that destroy parameters in the callee,
6217	// should we consider performing destruction when the function returns
6218	// instead?
6219	APValue &V = PVD ? Info.CurrentCall->createParam(Args: Call, PVD, LV)
6220	: Info.CurrentCall->createTemporary(Key: Arg, T: Arg->getType(),
6221	Scope: ScopeKind::Call, LV);
6222	if (!EvaluateInPlace(Result&: V, Info, This: LV, E: Arg))
6223	return false;
6224
6225	// Passing a null pointer to an __attribute__((nonnull)) parameter results in
6226	// undefined behavior, so is non-constant.
6227	if (NonNull && V.isLValue() && V.isNullPointer()) {
6228	Info.CCEDiag(Arg, diag::note_non_null_attribute_failed);
6229	return false;
6230	}
6231
6232	return true;
6233	}
6234
6235	/// Evaluate the arguments to a function call.
6236	static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call,
6237	EvalInfo &Info, const FunctionDecl *Callee,
6238	bool RightToLeft = false) {
6239	bool Success = true;
6240	llvm::SmallBitVector ForbiddenNullArgs;
6241	if (Callee->hasAttr<NonNullAttr>()) {
6242	ForbiddenNullArgs.resize(N: Args.size());
6243	for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
6244	if (!Attr->args_size()) {
6245	ForbiddenNullArgs.set();
6246	break;
6247	} else
6248	for (auto Idx : Attr->args()) {
6249	unsigned ASTIdx = Idx.getASTIndex();
6250	if (ASTIdx >= Args.size())
6251	continue;
6252	ForbiddenNullArgs[ASTIdx] = true;
6253	}
6254	}
6255	}
6256	for (unsigned I = 0; I < Args.size(); I++) {
6257	unsigned Idx = RightToLeft ? Args.size() - I - 1 : I;
6258	const ParmVarDecl *PVD =
6259	Idx < Callee->getNumParams() ? Callee->getParamDecl(i: Idx) : nullptr;
6260	bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx];
6261	if (!EvaluateCallArg(PVD, Arg: Args[Idx], Call, Info, NonNull)) {
6262	// If we're checking for a potential constant expression, evaluate all
6263	// initializers even if some of them fail.
6264	if (!Info.noteFailure())
6265	return false;
6266	Success = false;
6267	}
6268	}
6269	return Success;
6270	}
6271
6272	/// Perform a trivial copy from Param, which is the parameter of a copy or move
6273	/// constructor or assignment operator.
6274	static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param,
6275	const Expr *E, APValue &Result,
6276	bool CopyObjectRepresentation) {
6277	// Find the reference argument.
6278	CallStackFrame *Frame = Info.CurrentCall;
6279	APValue *RefValue = Info.getParamSlot(Call: Frame->Arguments, PVD: Param);
6280	if (!RefValue) {
6281	Info.FFDiag(E);
6282	return false;
6283	}
6284
6285	// Copy out the contents of the RHS object.
6286	LValue RefLValue;
6287	RefLValue.setFrom(Ctx&: Info.Ctx, V: *RefValue);
6288	return handleLValueToRValueConversion(
6289	Info, E, Param->getType().getNonReferenceType(), RefLValue, Result,
6290	CopyObjectRepresentation);
6291	}
6292
6293	/// Evaluate a function call.
6294	static bool HandleFunctionCall(SourceLocation CallLoc,
6295	const FunctionDecl *Callee, const LValue *This,
6296	const Expr *E, ArrayRef<const Expr *> Args,
6297	CallRef Call, const Stmt *Body, EvalInfo &Info,
6298	APValue &Result, const LValue *ResultSlot) {
6299	if (!Info.CheckCallLimit(Loc: CallLoc))
6300	return false;
6301
6302	CallStackFrame Frame(Info, E->getSourceRange(), Callee, This, E, Call);
6303
6304	// For a trivial copy or move assignment, perform an APValue copy. This is
6305	// essential for unions, where the operations performed by the assignment
6306	// operator cannot be represented as statements.
6307	//
6308	// Skip this for non-union classes with no fields; in that case, the defaulted
6309	// copy/move does not actually read the object.
6310	const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: Callee);
6311	if (MD && MD->isDefaulted() &&
6312	(MD->getParent()->isUnion() ||
6313	(MD->isTrivial() &&
6314	isReadByLvalueToRvalueConversion(RD: MD->getParent())))) {
6315	assert(This &&
6316	(MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
6317	APValue RHSValue;
6318	if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue,
6319	MD->getParent()->isUnion()))
6320	return false;
6321	if (!handleAssignment(Info, E: Args[0], LVal: *This, LValType: MD->getThisType(),
6322	Val&: RHSValue))
6323	return false;
6324	This->moveInto(V&: Result);
6325	return true;
6326	} else if (MD && isLambdaCallOperator(MD)) {
6327	// We're in a lambda; determine the lambda capture field maps unless we're
6328	// just constexpr checking a lambda's call operator. constexpr checking is
6329	// done before the captures have been added to the closure object (unless
6330	// we're inferring constexpr-ness), so we don't have access to them in this
6331	// case. But since we don't need the captures to constexpr check, we can
6332	// just ignore them.
6333	if (!Info.checkingPotentialConstantExpression())
6334	MD->getParent()->getCaptureFields(Captures&: Frame.LambdaCaptureFields,
6335	ThisCapture&: Frame.LambdaThisCaptureField);
6336	}
6337
6338	StmtResult Ret = {.Value: Result, .Slot: ResultSlot};
6339	EvalStmtResult ESR = EvaluateStmt(Result&: Ret, Info, S: Body);
6340	if (ESR == ESR_Succeeded) {
6341	if (Callee->getReturnType()->isVoidType())
6342	return true;
6343	Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return);
6344	}
6345	return ESR == ESR_Returned;
6346	}
6347
6348	/// Evaluate a constructor call.
6349	static bool HandleConstructorCall(const Expr *E, const LValue &This,
6350	CallRef Call,
6351	const CXXConstructorDecl *Definition,
6352	EvalInfo &Info, APValue &Result) {
6353	SourceLocation CallLoc = E->getExprLoc();
6354	if (!Info.CheckCallLimit(Loc: CallLoc))
6355	return false;
6356
6357	const CXXRecordDecl *RD = Definition->getParent();
6358	if (RD->getNumVBases()) {
6359	Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6360	return false;
6361	}
6362
6363	EvalInfo::EvaluatingConstructorRAII EvalObj(
6364	Info,
6365	ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
6366	RD->getNumBases());
6367	CallStackFrame Frame(Info, E->getSourceRange(), Definition, &This, E, Call);
6368
6369	// FIXME: Creating an APValue just to hold a nonexistent return value is
6370	// wasteful.
6371	APValue RetVal;
6372	StmtResult Ret = {.Value: RetVal, .Slot: nullptr};
6373
6374	// If it's a delegating constructor, delegate.
6375	if (Definition->isDelegatingConstructor()) {
6376	CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
6377	if ((*I)->getInit()->isValueDependent()) {
6378	if (!EvaluateDependentExpr(E: (*I)->getInit(), Info))
6379	return false;
6380	} else {
6381	FullExpressionRAII InitScope(Info);
6382	if (!EvaluateInPlace(Result, Info, This, E: (*I)->getInit()) ||
6383	!InitScope.destroy())
6384	return false;
6385	}
6386	return EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) != ESR_Failed;
6387	}
6388
6389	// For a trivial copy or move constructor, perform an APValue copy. This is
6390	// essential for unions (or classes with anonymous union members), where the
6391	// operations performed by the constructor cannot be represented by
6392	// ctor-initializers.
6393	//
6394	// Skip this for empty non-union classes; we should not perform an
6395	// lvalue-to-rvalue conversion on them because their copy constructor does not
6396	// actually read them.
6397	if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
6398	(Definition->getParent()->isUnion() ||
6399	(Definition->isTrivial() &&
6400	isReadByLvalueToRvalueConversion(Definition->getParent())))) {
6401	return handleTrivialCopy(Info, Definition->getParamDecl(0), E, Result,
6402	Definition->getParent()->isUnion());
6403	}
6404
6405	// Reserve space for the struct members.
6406	if (!Result.hasValue()) {
6407	if (!RD->isUnion())
6408	Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
6409	std::distance(RD->field_begin(), RD->field_end()));
6410	else
6411	// A union starts with no active member.
6412	Result = APValue((const FieldDecl*)nullptr);
6413	}
6414
6415	if (RD->isInvalidDecl()) return false;
6416	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6417
6418	// A scope for temporaries lifetime-extended by reference members.
6419	BlockScopeRAII LifetimeExtendedScope(Info);
6420
6421	bool Success = true;
6422	unsigned BasesSeen = 0;
6423	#ifndef NDEBUG
6424	CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
6425	#endif
6426	CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
6427	auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
6428	// We might be initializing the same field again if this is an indirect
6429	// field initialization.
6430	if (FieldIt == RD->field_end() ||
6431	FieldIt->getFieldIndex() > FD->getFieldIndex()) {
6432	assert(Indirect && "fields out of order?");
6433	return;
6434	}
6435
6436	// Default-initialize any fields with no explicit initializer.
6437	for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) {
6438	assert(FieldIt != RD->field_end() && "missing field?");
6439	if (!FieldIt->isUnnamedBitField())
6440	Success &= handleDefaultInitValue(
6441	FieldIt->getType(),
6442	Result.getStructField(i: FieldIt->getFieldIndex()));
6443	}
6444	++FieldIt;
6445	};
6446	for (const auto *I : Definition->inits()) {
6447	LValue Subobject = This;
6448	LValue SubobjectParent = This;
6449	APValue *Value = &Result;
6450
6451	// Determine the subobject to initialize.
6452	FieldDecl *FD = nullptr;
6453	if (I->isBaseInitializer()) {
6454	QualType BaseType(I->getBaseClass(), 0);
6455	#ifndef NDEBUG
6456	// Non-virtual base classes are initialized in the order in the class
6457	// definition. We have already checked for virtual base classes.
6458	assert(!BaseIt->isVirtual() && "virtual base for literal type");
6459	assert(Info.Ctx.hasSameUnqualifiedType(BaseIt->getType(), BaseType) &&
6460	"base class initializers not in expected order");
6461	++BaseIt;
6462	#endif
6463	if (!HandleLValueDirectBase(Info, E: I->getInit(), Obj&: Subobject, Derived: RD,
6464	Base: BaseType->getAsCXXRecordDecl(), RL: &Layout))
6465	return false;
6466	Value = &Result.getStructBase(i: BasesSeen++);
6467	} else if ((FD = I->getMember())) {
6468	if (!HandleLValueMember(Info, E: I->getInit(), LVal&: Subobject, FD, RL: &Layout))
6469	return false;
6470	if (RD->isUnion()) {
6471	Result = APValue(FD);
6472	Value = &Result.getUnionValue();
6473	} else {
6474	SkipToField(FD, false);
6475	Value = &Result.getStructField(i: FD->getFieldIndex());
6476	}
6477	} else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
6478	// Walk the indirect field decl's chain to find the object to initialize,
6479	// and make sure we've initialized every step along it.
6480	auto IndirectFieldChain = IFD->chain();
6481	for (auto *C : IndirectFieldChain) {
6482	FD = cast<FieldDecl>(Val: C);
6483	CXXRecordDecl *CD = cast<CXXRecordDecl>(Val: FD->getParent());
6484	// Switch the union field if it differs. This happens if we had
6485	// preceding zero-initialization, and we're now initializing a union
6486	// subobject other than the first.
6487	// FIXME: In this case, the values of the other subobjects are
6488	// specified, since zero-initialization sets all padding bits to zero.
6489	if (!Value->hasValue() ||
6490	(Value->isUnion() && Value->getUnionField() != FD)) {
6491	if (CD->isUnion())
6492	*Value = APValue(FD);
6493	else
6494	// FIXME: This immediately starts the lifetime of all members of
6495	// an anonymous struct. It would be preferable to strictly start
6496	// member lifetime in initialization order.
6497	Success &=
6498	handleDefaultInitValue(T: Info.Ctx.getRecordType(CD), Result&: *Value);
6499	}
6500	// Store Subobject as its parent before updating it for the last element
6501	// in the chain.
6502	if (C == IndirectFieldChain.back())
6503	SubobjectParent = Subobject;
6504	if (!HandleLValueMember(Info, E: I->getInit(), LVal&: Subobject, FD))
6505	return false;
6506	if (CD->isUnion())
6507	Value = &Value->getUnionValue();
6508	else {
6509	if (C == IndirectFieldChain.front() && !RD->isUnion())
6510	SkipToField(FD, true);
6511	Value = &Value->getStructField(i: FD->getFieldIndex());
6512	}
6513	}
6514	} else {
6515	llvm_unreachable("unknown base initializer kind");
6516	}
6517
6518	// Need to override This for implicit field initializers as in this case
6519	// This refers to innermost anonymous struct/union containing initializer,
6520	// not to currently constructed class.
6521	const Expr *Init = I->getInit();
6522	if (Init->isValueDependent()) {
6523	if (!EvaluateDependentExpr(E: Init, Info))
6524	return false;
6525	} else {
6526	ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
6527	isa<CXXDefaultInitExpr>(Val: Init));
6528	FullExpressionRAII InitScope(Info);
6529	if (!EvaluateInPlace(Result&: *Value, Info, This: Subobject, E: Init) ||
6530	(FD && FD->isBitField() &&
6531	!truncateBitfieldValue(Info, E: Init, Value&: *Value, FD))) {
6532	// If we're checking for a potential constant expression, evaluate all
6533	// initializers even if some of them fail.
6534	if (!Info.noteFailure())
6535	return false;
6536	Success = false;
6537	}
6538	}
6539
6540	// This is the point at which the dynamic type of the object becomes this
6541	// class type.
6542	if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
6543	EvalObj.finishedConstructingBases();
6544	}
6545
6546	// Default-initialize any remaining fields.
6547	if (!RD->isUnion()) {
6548	for (; FieldIt != RD->field_end(); ++FieldIt) {
6549	if (!FieldIt->isUnnamedBitField())
6550	Success &= handleDefaultInitValue(
6551	FieldIt->getType(),
6552	Result.getStructField(i: FieldIt->getFieldIndex()));
6553	}
6554	}
6555
6556	EvalObj.finishedConstructingFields();
6557
6558	return Success &&
6559	EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) != ESR_Failed &&
6560	LifetimeExtendedScope.destroy();
6561	}
6562
6563	static bool HandleConstructorCall(const Expr *E, const LValue &This,
6564	ArrayRef<const Expr*> Args,
6565	const CXXConstructorDecl *Definition,
6566	EvalInfo &Info, APValue &Result) {
6567	CallScopeRAII CallScope(Info);
6568	CallRef Call = Info.CurrentCall->createCall(Definition);
6569	if (!EvaluateArgs(Args, Call, Info, Definition))
6570	return false;
6571
6572	return HandleConstructorCall(E, This, Call, Definition, Info, Result) &&
6573	CallScope.destroy();
6574	}
6575
6576	static bool HandleDestructionImpl(EvalInfo &Info, SourceRange CallRange,
6577	const LValue &This, APValue &Value,
6578	QualType T) {
6579	// Objects can only be destroyed while they're within their lifetimes.
6580	// FIXME: We have no representation for whether an object of type nullptr_t
6581	// is in its lifetime; it usually doesn't matter. Perhaps we should model it
6582	// as indeterminate instead?
6583	if (Value.isAbsent() && !T->isNullPtrType()) {
6584	APValue Printable;
6585	This.moveInto(V&: Printable);
6586	Info.FFDiag(CallRange.getBegin(),
6587	diag::note_constexpr_destroy_out_of_lifetime)
6588	<< Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T));
6589	return false;
6590	}
6591
6592	// Invent an expression for location purposes.
6593	// FIXME: We shouldn't need to do this.
6594	OpaqueValueExpr LocE(CallRange.getBegin(), Info.Ctx.IntTy, VK_PRValue);
6595
6596	// For arrays, destroy elements right-to-left.
6597	if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
6598	uint64_t Size = CAT->getZExtSize();
6599	QualType ElemT = CAT->getElementType();
6600
6601	if (!CheckArraySize(Info, CAT, CallLoc: CallRange.getBegin()))
6602	return false;
6603
6604	LValue ElemLV = This;
6605	ElemLV.addArray(Info, &LocE, CAT);
6606	if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size))
6607	return false;
6608
6609	// Ensure that we have actual array elements available to destroy; the
6610	// destructors might mutate the value, so we can't run them on the array
6611	// filler.
6612	if (Size && Size > Value.getArrayInitializedElts())
6613	expandArray(Array&: Value, Index: Value.getArraySize() - 1);
6614
6615	for (; Size != 0; --Size) {
6616	APValue &Elem = Value.getArrayInitializedElt(I: Size - 1);
6617	if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) ||
6618	!HandleDestructionImpl(Info, CallRange, This: ElemLV, Value&: Elem, T: ElemT))
6619	return false;
6620	}
6621
6622	// End the lifetime of this array now.
6623	Value = APValue();
6624	return true;
6625	}
6626
6627	const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
6628	if (!RD) {
6629	if (T.isDestructedType()) {
6630	Info.FFDiag(CallRange.getBegin(),
6631	diag::note_constexpr_unsupported_destruction)
6632	<< T;
6633	return false;
6634	}
6635
6636	Value = APValue();
6637	return true;
6638	}
6639
6640	if (RD->getNumVBases()) {
6641	Info.FFDiag(CallRange.getBegin(), diag::note_constexpr_virtual_base) << RD;
6642	return false;
6643	}
6644
6645	const CXXDestructorDecl *DD = RD->getDestructor();
6646	if (!DD && !RD->hasTrivialDestructor()) {
6647	Info.FFDiag(Loc: CallRange.getBegin());
6648	return false;
6649	}
6650
6651	if (!DD || DD->isTrivial() ||
6652	(RD->isAnonymousStructOrUnion() && RD->isUnion())) {
6653	// A trivial destructor just ends the lifetime of the object. Check for
6654	// this case before checking for a body, because we might not bother
6655	// building a body for a trivial destructor. Note that it doesn't matter
6656	// whether the destructor is constexpr in this case; all trivial
6657	// destructors are constexpr.
6658	//
6659	// If an anonymous union would be destroyed, some enclosing destructor must
6660	// have been explicitly defined, and the anonymous union destruction should
6661	// have no effect.
6662	Value = APValue();
6663	return true;
6664	}
6665
6666	if (!Info.CheckCallLimit(Loc: CallRange.getBegin()))
6667	return false;
6668
6669	const FunctionDecl *Definition = nullptr;
6670	const Stmt *Body = DD->getBody(Definition);
6671
6672	if (!CheckConstexprFunction(Info, CallRange.getBegin(), DD, Definition, Body))
6673	return false;
6674
6675	CallStackFrame Frame(Info, CallRange, Definition, &This, /*CallExpr=*/nullptr,
6676	CallRef());
6677
6678	// We're now in the period of destruction of this object.
6679	unsigned BasesLeft = RD->getNumBases();
6680	EvalInfo::EvaluatingDestructorRAII EvalObj(
6681	Info,
6682	ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries});
6683	if (!EvalObj.DidInsert) {
6684	// C++2a [class.dtor]p19:
6685	// the behavior is undefined if the destructor is invoked for an object
6686	// whose lifetime has ended
6687	// (Note that formally the lifetime ends when the period of destruction
6688	// begins, even though certain uses of the object remain valid until the
6689	// period of destruction ends.)
6690	Info.FFDiag(CallRange.getBegin(), diag::note_constexpr_double_destroy);
6691	return false;
6692	}
6693
6694	// FIXME: Creating an APValue just to hold a nonexistent return value is
6695	// wasteful.
6696	APValue RetVal;
6697	StmtResult Ret = {.Value: RetVal, .Slot: nullptr};
6698	if (EvaluateStmt(Result&: Ret, Info, S: Definition->getBody()) == ESR_Failed)
6699	return false;
6700
6701	// A union destructor does not implicitly destroy its members.
6702	if (RD->isUnion())
6703	return true;
6704
6705	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6706
6707	// We don't have a good way to iterate fields in reverse, so collect all the
6708	// fields first and then walk them backwards.
6709	SmallVector<FieldDecl*, 16> Fields(RD->fields());
6710	for (const FieldDecl *FD : llvm::reverse(Fields)) {
6711	if (FD->isUnnamedBitField())
6712	continue;
6713
6714	LValue Subobject = This;
6715	if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout))
6716	return false;
6717
6718	APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex());
6719	if (!HandleDestructionImpl(Info, CallRange, Subobject, *SubobjectValue,
6720	FD->getType()))
6721	return false;
6722	}
6723
6724	if (BasesLeft != 0)
6725	EvalObj.startedDestroyingBases();
6726
6727	// Destroy base classes in reverse order.
6728	for (const CXXBaseSpecifier &Base : llvm::reverse(C: RD->bases())) {
6729	--BasesLeft;
6730
6731	QualType BaseType = Base.getType();
6732	LValue Subobject = This;
6733	if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD,
6734	BaseType->getAsCXXRecordDecl(), &Layout))
6735	return false;
6736
6737	APValue *SubobjectValue = &Value.getStructBase(i: BasesLeft);
6738	if (!HandleDestructionImpl(Info, CallRange, This: Subobject, Value&: *SubobjectValue,
6739	T: BaseType))
6740	return false;
6741	}
6742	assert(BasesLeft == 0 && "NumBases was wrong?");
6743
6744	// The period of destruction ends now. The object is gone.
6745	Value = APValue();
6746	return true;
6747	}
6748
6749	namespace {
6750	struct DestroyObjectHandler {
6751	EvalInfo &Info;
6752	const Expr *E;
6753	const LValue &This;
6754	const AccessKinds AccessKind;
6755
6756	typedef bool result_type;
6757	bool failed() { return false; }
6758	bool found(APValue &Subobj, QualType SubobjType) {
6759	return HandleDestructionImpl(Info, E->getSourceRange(), This, Subobj,
6760	SubobjType);
6761	}
6762	bool found(APSInt &Value, QualType SubobjType) {
6763	Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6764	return false;
6765	}
6766	bool found(APFloat &Value, QualType SubobjType) {
6767	Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6768	return false;
6769	}
6770	};
6771	}
6772
6773	/// Perform a destructor or pseudo-destructor call on the given object, which
6774	/// might in general not be a complete object.
6775	static bool HandleDestruction(EvalInfo &Info, const Expr *E,
6776	const LValue &This, QualType ThisType) {
6777	CompleteObject Obj = findCompleteObject(Info, E, AK: AK_Destroy, LVal: This, LValType: ThisType);
6778	DestroyObjectHandler Handler = {.Info: Info, .E: E, .This: This, .AccessKind: AK_Destroy};
6779	return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
6780	}
6781
6782	/// Destroy and end the lifetime of the given complete object.
6783	static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
6784	APValue::LValueBase LVBase, APValue &Value,
6785	QualType T) {
6786	// If we've had an unmodeled side-effect, we can't rely on mutable state
6787	// (such as the object we're about to destroy) being correct.
6788	if (Info.EvalStatus.HasSideEffects)
6789	return false;
6790
6791	LValue LV;
6792	LV.set(B: {LVBase});
6793	return HandleDestructionImpl(Info, CallRange: Loc, This: LV, Value, T);
6794	}
6795
6796	/// Perform a call to 'operator new' or to `__builtin_operator_new'.
6797	static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
6798	LValue &Result) {
6799	if (Info.checkingPotentialConstantExpression() ||
6800	Info.SpeculativeEvaluationDepth)
6801	return false;
6802
6803	// This is permitted only within a call to std::allocator<T>::allocate.
6804	auto Caller = Info.getStdAllocatorCaller(FnName: "allocate");
6805	if (!Caller) {
6806	Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20
6807	? diag::note_constexpr_new_untyped
6808	: diag::note_constexpr_new);
6809	return false;
6810	}
6811
6812	QualType ElemType = Caller.ElemType;
6813	if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
6814	Info.FFDiag(E->getExprLoc(),
6815	diag::note_constexpr_new_not_complete_object_type)
6816	<< (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
6817	return false;
6818	}
6819
6820	APSInt ByteSize;
6821	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: ByteSize, Info))
6822	return false;
6823	bool IsNothrow = false;
6824	for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
6825	EvaluateIgnoredValue(Info, E: E->getArg(Arg: I));
6826	IsNothrow |= E->getType()->isNothrowT();
6827	}
6828
6829	CharUnits ElemSize;
6830	if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize))
6831	return false;
6832	APInt Size, Remainder;
6833	APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
6834	APInt::udivrem(LHS: ByteSize, RHS: ElemSizeAP, Quotient&: Size, Remainder);
6835	if (Remainder != 0) {
6836	// This likely indicates a bug in the implementation of 'std::allocator'.
6837	Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size)
6838	<< ByteSize << APSInt(ElemSizeAP, true) << ElemType;
6839	return false;
6840	}
6841
6842	if (!Info.CheckArraySize(Loc: E->getBeginLoc(), BitWidth: ByteSize.getActiveBits(),
6843	ElemCount: Size.getZExtValue(), /*Diag=*/!IsNothrow)) {
6844	if (IsNothrow) {
6845	Result.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
6846	return true;
6847	}
6848	return false;
6849	}
6850
6851	QualType AllocType = Info.Ctx.getConstantArrayType(
6852	EltTy: ElemType, ArySize: Size, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
6853	APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
6854	*Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
6855	Result.addArray(Info, E, cast<ConstantArrayType>(Val&: AllocType));
6856	return true;
6857	}
6858
6859	static bool hasVirtualDestructor(QualType T) {
6860	if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6861	if (CXXDestructorDecl *DD = RD->getDestructor())
6862	return DD->isVirtual();
6863	return false;
6864	}
6865
6866	static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
6867	if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6868	if (CXXDestructorDecl *DD = RD->getDestructor())
6869	return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
6870	return nullptr;
6871	}
6872
6873	/// Check that the given object is a suitable pointer to a heap allocation that
6874	/// still exists and is of the right kind for the purpose of a deletion.
6875	///
6876	/// On success, returns the heap allocation to deallocate. On failure, produces
6877	/// a diagnostic and returns std::nullopt.
6878	static std::optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
6879	const LValue &Pointer,
6880	DynAlloc::Kind DeallocKind) {
6881	auto PointerAsString = [&] {
6882	return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy);
6883	};
6884
6885	DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
6886	if (!DA) {
6887	Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc)
6888	<< PointerAsString();
6889	if (Pointer.Base)
6890	NoteLValueLocation(Info, Base: Pointer.Base);
6891	return std::nullopt;
6892	}
6893
6894	std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
6895	if (!Alloc) {
6896	Info.FFDiag(E, diag::note_constexpr_double_delete);
6897	return std::nullopt;
6898	}
6899
6900	if (DeallocKind != (*Alloc)->getKind()) {
6901	QualType AllocType = Pointer.Base.getDynamicAllocType();
6902	Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch)
6903	<< DeallocKind << (*Alloc)->getKind() << AllocType;
6904	NoteLValueLocation(Info, Base: Pointer.Base);
6905	return std::nullopt;
6906	}
6907
6908	bool Subobject = false;
6909	if (DeallocKind == DynAlloc::New) {
6910	Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
6911	Pointer.Designator.isOnePastTheEnd();
6912	} else {
6913	Subobject = Pointer.Designator.Entries.size() != 1 ||
6914	Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
6915	}
6916	if (Subobject) {
6917	Info.FFDiag(E, diag::note_constexpr_delete_subobject)
6918	<< PointerAsString() << Pointer.Designator.isOnePastTheEnd();
6919	return std::nullopt;
6920	}
6921
6922	return Alloc;
6923	}
6924
6925	// Perform a call to 'operator delete' or '__builtin_operator_delete'.
6926	bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
6927	if (Info.checkingPotentialConstantExpression() ||
6928	Info.SpeculativeEvaluationDepth)
6929	return false;
6930
6931	// This is permitted only within a call to std::allocator<T>::deallocate.
6932	if (!Info.getStdAllocatorCaller(FnName: "deallocate")) {
6933	Info.FFDiag(E->getExprLoc());
6934	return true;
6935	}
6936
6937	LValue Pointer;
6938	if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: Pointer, Info))
6939	return false;
6940	for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
6941	EvaluateIgnoredValue(Info, E: E->getArg(Arg: I));
6942
6943	if (Pointer.Designator.Invalid)
6944	return false;
6945
6946	// Deleting a null pointer would have no effect, but it's not permitted by
6947	// std::allocator<T>::deallocate's contract.
6948	if (Pointer.isNullPointer()) {
6949	Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_deallocate_null);
6950	return true;
6951	}
6952
6953	if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator))
6954	return false;
6955
6956	Info.HeapAllocs.erase(x: Pointer.Base.get<DynamicAllocLValue>());
6957	return true;
6958	}
6959
6960	//===----------------------------------------------------------------------===//
6961	// Generic Evaluation
6962	//===----------------------------------------------------------------------===//
6963	namespace {
6964
6965	class BitCastBuffer {
6966	// FIXME: We're going to need bit-level granularity when we support
6967	// bit-fields.
6968	// FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
6969	// we don't support a host or target where that is the case. Still, we should
6970	// use a more generic type in case we ever do.
6971	SmallVector<std::optional<unsigned char>, 32> Bytes;
6972
6973	static_assert(std::numeric_limits<unsigned char>::digits >= 8,
6974	"Need at least 8 bit unsigned char");
6975
6976	bool TargetIsLittleEndian;
6977
6978	public:
6979	BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
6980	: Bytes(Width.getQuantity()),
6981	TargetIsLittleEndian(TargetIsLittleEndian) {}
6982
6983	[[nodiscard]] bool readObject(CharUnits Offset, CharUnits Width,
6984	SmallVectorImpl<unsigned char> &Output) const {
6985	for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
6986	// If a byte of an integer is uninitialized, then the whole integer is
6987	// uninitialized.
6988	if (!Bytes[I.getQuantity()])
6989	return false;
6990	Output.push_back(Elt: *Bytes[I.getQuantity()]);
6991	}
6992	if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6993	std::reverse(first: Output.begin(), last: Output.end());
6994	return true;
6995	}
6996
6997	void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
6998	if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6999	std::reverse(first: Input.begin(), last: Input.end());
7000
7001	size_t Index = 0;
7002	for (unsigned char Byte : Input) {
7003	assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?");
7004	Bytes[Offset.getQuantity() + Index] = Byte;
7005	++Index;
7006	}
7007	}
7008
7009	size_t size() { return Bytes.size(); }
7010	};
7011
7012	/// Traverse an APValue to produce an BitCastBuffer, emulating how the current
7013	/// target would represent the value at runtime.
7014	class APValueToBufferConverter {
7015	EvalInfo &Info;
7016	BitCastBuffer Buffer;
7017	const CastExpr *BCE;
7018
7019	APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
7020	const CastExpr *BCE)
7021	: Info(Info),
7022	Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
7023	BCE(BCE) {}
7024
7025	bool visit(const APValue &Val, QualType Ty) {
7026	return visit(Val, Ty, Offset: CharUnits::fromQuantity(Quantity: 0));
7027	}
7028
7029	// Write out Val with type Ty into Buffer starting at Offset.
7030	bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
7031	assert((size_t)Offset.getQuantity() <= Buffer.size());
7032
7033	// As a special case, nullptr_t has an indeterminate value.
7034	if (Ty->isNullPtrType())
7035	return true;
7036
7037	// Dig through Src to find the byte at SrcOffset.
7038	switch (Val.getKind()) {
7039	case APValue::Indeterminate:
7040	case APValue::None:
7041	return true;
7042
7043	case APValue::Int:
7044	return visitInt(Val: Val.getInt(), Ty, Offset);
7045	case APValue::Float:
7046	return visitFloat(Val: Val.getFloat(), Ty, Offset);
7047	case APValue::Array:
7048	return visitArray(Val, Ty, Offset);
7049	case APValue::Struct:
7050	return visitRecord(Val, Ty, Offset);
7051	case APValue::Vector:
7052	return visitVector(Val, Ty, Offset);
7053
7054	case APValue::ComplexInt:
7055	case APValue::ComplexFloat:
7056	case APValue::FixedPoint:
7057	// FIXME: We should support these.
7058
7059	case APValue::Union:
7060	case APValue::MemberPointer:
7061	case APValue::AddrLabelDiff: {
7062	Info.FFDiag(BCE->getBeginLoc(),
7063	diag::note_constexpr_bit_cast_unsupported_type)
7064	<< Ty;
7065	return false;
7066	}
7067
7068	case APValue::LValue:
7069	llvm_unreachable("LValue subobject in bit_cast?");
7070	}
7071	llvm_unreachable("Unhandled APValue::ValueKind");
7072	}
7073
7074	bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
7075	const RecordDecl *RD = Ty->getAsRecordDecl();
7076	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
7077
7078	// Visit the base classes.
7079	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD)) {
7080	for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7081	const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7082	CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7083
7084	if (!visitRecord(Val: Val.getStructBase(i: I), Ty: BS.getType(),
7085	Offset: Layout.getBaseClassOffset(Base: BaseDecl) + Offset))
7086	return false;
7087	}
7088	}
7089
7090	// Visit the fields.
7091	unsigned FieldIdx = 0;
7092	for (FieldDecl *FD : RD->fields()) {
7093	if (FD->isBitField()) {
7094	Info.FFDiag(BCE->getBeginLoc(),
7095	diag::note_constexpr_bit_cast_unsupported_bitfield);
7096	return false;
7097	}
7098
7099	uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldNo: FieldIdx);
7100
7101	assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&
7102	"only bit-fields can have sub-char alignment");
7103	CharUnits FieldOffset =
7104	Info.Ctx.toCharUnitsFromBits(BitSize: FieldOffsetBits) + Offset;
7105	QualType FieldTy = FD->getType();
7106	if (!visit(Val: Val.getStructField(i: FieldIdx), Ty: FieldTy, Offset: FieldOffset))
7107	return false;
7108	++FieldIdx;
7109	}
7110
7111	return true;
7112	}
7113
7114	bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
7115	const auto *CAT =
7116	dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
7117	if (!CAT)
7118	return false;
7119
7120	CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
7121	unsigned NumInitializedElts = Val.getArrayInitializedElts();
7122	unsigned ArraySize = Val.getArraySize();
7123	// First, initialize the initialized elements.
7124	for (unsigned I = 0; I != NumInitializedElts; ++I) {
7125	const APValue &SubObj = Val.getArrayInitializedElt(I);
7126	if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
7127	return false;
7128	}
7129
7130	// Next, initialize the rest of the array using the filler.
7131	if (Val.hasArrayFiller()) {
7132	const APValue &Filler = Val.getArrayFiller();
7133	for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
7134	if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth))
7135	return false;
7136	}
7137	}
7138
7139	return true;
7140	}
7141
7142	bool visitVector(const APValue &Val, QualType Ty, CharUnits Offset) {
7143	const VectorType *VTy = Ty->castAs<VectorType>();
7144	QualType EltTy = VTy->getElementType();
7145	unsigned NElts = VTy->getNumElements();
7146	unsigned EltSize =
7147	VTy->isExtVectorBoolType() ? 1 : Info.Ctx.getTypeSize(T: EltTy);
7148
7149	if ((NElts * EltSize) % Info.Ctx.getCharWidth() != 0) {
7150	// The vector's size in bits is not a multiple of the target's byte size,
7151	// so its layout is unspecified. For now, we'll simply treat these cases
7152	// as unsupported (this should only be possible with OpenCL bool vectors
7153	// whose element count isn't a multiple of the byte size).
7154	Info.FFDiag(BCE->getBeginLoc(),
7155	diag::note_constexpr_bit_cast_invalid_vector)
7156	<< Ty.getCanonicalType() << EltSize << NElts
7157	<< Info.Ctx.getCharWidth();
7158	return false;
7159	}
7160
7161	if (EltTy->isRealFloatingType() && &Info.Ctx.getFloatTypeSemantics(T: EltTy) ==
7162	&APFloat::x87DoubleExtended()) {
7163	// The layout for x86_fp80 vectors seems to be handled very inconsistently
7164	// by both clang and LLVM, so for now we won't allow bit_casts involving
7165	// it in a constexpr context.
7166	Info.FFDiag(BCE->getBeginLoc(),
7167	diag::note_constexpr_bit_cast_unsupported_type)
7168	<< EltTy;
7169	return false;
7170	}
7171
7172	if (VTy->isExtVectorBoolType()) {
7173	// Special handling for OpenCL bool vectors:
7174	// Since these vectors are stored as packed bits, but we can't write
7175	// individual bits to the BitCastBuffer, we'll buffer all of the elements
7176	// together into an appropriately sized APInt and write them all out at
7177	// once. Because we don't accept vectors where NElts * EltSize isn't a
7178	// multiple of the char size, there will be no padding space, so we don't
7179	// have to worry about writing data which should have been left
7180	// uninitialized.
7181	bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
7182
7183	llvm::APInt Res = llvm::APInt::getZero(numBits: NElts);
7184	for (unsigned I = 0; I < NElts; ++I) {
7185	const llvm::APSInt &EltAsInt = Val.getVectorElt(I).getInt();
7186	assert(EltAsInt.isUnsigned() && EltAsInt.getBitWidth() == 1 &&
7187	"bool vector element must be 1-bit unsigned integer!");
7188
7189	Res.insertBits(SubBits: EltAsInt, bitPosition: BigEndian ? (NElts - I - 1) : I);
7190	}
7191
7192	SmallVector<uint8_t, 8> Bytes(NElts / 8);
7193	llvm::StoreIntToMemory(IntVal: Res, Dst: &*Bytes.begin(), StoreBytes: NElts / 8);
7194	Buffer.writeObject(Offset, Input&: Bytes);
7195	} else {
7196	// Iterate over each of the elements and write them out to the buffer at
7197	// the appropriate offset.
7198	CharUnits EltSizeChars = Info.Ctx.getTypeSizeInChars(T: EltTy);
7199	for (unsigned I = 0; I < NElts; ++I) {
7200	if (!visit(Val: Val.getVectorElt(I), Ty: EltTy, Offset: Offset + I * EltSizeChars))
7201	return false;
7202	}
7203	}
7204
7205	return true;
7206	}
7207
7208	bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
7209	APSInt AdjustedVal = Val;
7210	unsigned Width = AdjustedVal.getBitWidth();
7211	if (Ty->isBooleanType()) {
7212	Width = Info.Ctx.getTypeSize(T: Ty);
7213	AdjustedVal = AdjustedVal.extend(width: Width);
7214	}
7215
7216	SmallVector<uint8_t, 8> Bytes(Width / 8);
7217	llvm::StoreIntToMemory(IntVal: AdjustedVal, Dst: &*Bytes.begin(), StoreBytes: Width / 8);
7218	Buffer.writeObject(Offset, Input&: Bytes);
7219	return true;
7220	}
7221
7222	bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
7223	APSInt AsInt(Val.bitcastToAPInt());
7224	return visitInt(Val: AsInt, Ty, Offset);
7225	}
7226
7227	public:
7228	static std::optional<BitCastBuffer>
7229	convert(EvalInfo &Info, const APValue &Src, const CastExpr *BCE) {
7230	CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
7231	APValueToBufferConverter Converter(Info, DstSize, BCE);
7232	if (!Converter.visit(Val: Src, Ty: BCE->getSubExpr()->getType()))
7233	return std::nullopt;
7234	return Converter.Buffer;
7235	}
7236	};
7237
7238	/// Write an BitCastBuffer into an APValue.
7239	class BufferToAPValueConverter {
7240	EvalInfo &Info;
7241	const BitCastBuffer &Buffer;
7242	const CastExpr *BCE;
7243
7244	BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
7245	const CastExpr *BCE)
7246	: Info(Info), Buffer(Buffer), BCE(BCE) {}
7247
7248	// Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
7249	// with an invalid type, so anything left is a deficiency on our part (FIXME).
7250	// Ideally this will be unreachable.
7251	std::nullopt_t unsupportedType(QualType Ty) {
7252	Info.FFDiag(BCE->getBeginLoc(),
7253	diag::note_constexpr_bit_cast_unsupported_type)
7254	<< Ty;
7255	return std::nullopt;
7256	}
7257
7258	std::nullopt_t unrepresentableValue(QualType Ty, const APSInt &Val) {
7259	Info.FFDiag(BCE->getBeginLoc(),
7260	diag::note_constexpr_bit_cast_unrepresentable_value)
7261	<< Ty << toString(Val, /*Radix=*/10);
7262	return std::nullopt;
7263	}
7264
7265	std::optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
7266	const EnumType *EnumSugar = nullptr) {
7267	if (T->isNullPtrType()) {
7268	uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QT: QualType(T, 0));
7269	return APValue((Expr *)nullptr,
7270	/*Offset=*/CharUnits::fromQuantity(Quantity: NullValue),
7271	APValue::NoLValuePath{}, /*IsNullPtr=*/true);
7272	}
7273
7274	CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
7275
7276	// Work around floating point types that contain unused padding bytes. This
7277	// is really just `long double` on x86, which is the only fundamental type
7278	// with padding bytes.
7279	if (T->isRealFloatingType()) {
7280	const llvm::fltSemantics &Semantics =
7281	Info.Ctx.getFloatTypeSemantics(T: QualType(T, 0));
7282	unsigned NumBits = llvm::APFloatBase::getSizeInBits(Sem: Semantics);
7283	assert(NumBits % 8 == 0);
7284	CharUnits NumBytes = CharUnits::fromQuantity(Quantity: NumBits / 8);
7285	if (NumBytes != SizeOf)
7286	SizeOf = NumBytes;
7287	}
7288
7289	SmallVector<uint8_t, 8> Bytes;
7290	if (!Buffer.readObject(Offset, Width: SizeOf, Output&: Bytes)) {
7291	// If this is std::byte or unsigned char, then its okay to store an
7292	// indeterminate value.
7293	bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
7294	bool IsUChar =
7295	!EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) ||
7296	T->isSpecificBuiltinType(BuiltinType::Char_U));
7297	if (!IsStdByte && !IsUChar) {
7298	QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
7299	Info.FFDiag(BCE->getExprLoc(),
7300	diag::note_constexpr_bit_cast_indet_dest)
7301	<< DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
7302	return std::nullopt;
7303	}
7304
7305	return APValue::IndeterminateValue();
7306	}
7307
7308	APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
7309	llvm::LoadIntFromMemory(IntVal&: Val, Src: &*Bytes.begin(), LoadBytes: Bytes.size());
7310
7311	if (T->isIntegralOrEnumerationType()) {
7312	Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
7313
7314	unsigned IntWidth = Info.Ctx.getIntWidth(T: QualType(T, 0));
7315	if (IntWidth != Val.getBitWidth()) {
7316	APSInt Truncated = Val.trunc(width: IntWidth);
7317	if (Truncated.extend(width: Val.getBitWidth()) != Val)
7318	return unrepresentableValue(Ty: QualType(T, 0), Val);
7319	Val = Truncated;
7320	}
7321
7322	return APValue(Val);
7323	}
7324
7325	if (T->isRealFloatingType()) {
7326	const llvm::fltSemantics &Semantics =
7327	Info.Ctx.getFloatTypeSemantics(T: QualType(T, 0));
7328	return APValue(APFloat(Semantics, Val));
7329	}
7330
7331	return unsupportedType(Ty: QualType(T, 0));
7332	}
7333
7334	std::optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
7335	const RecordDecl *RD = RTy->getAsRecordDecl();
7336	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
7337
7338	unsigned NumBases = 0;
7339	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
7340	NumBases = CXXRD->getNumBases();
7341
7342	APValue ResultVal(APValue::UninitStruct(), NumBases,
7343	std::distance(RD->field_begin(), RD->field_end()));
7344
7345	// Visit the base classes.
7346	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
7347	for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7348	const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7349	CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7350
7351	std::optional<APValue> SubObj = visitType(
7352	BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
7353	if (!SubObj)
7354	return std::nullopt;
7355	ResultVal.getStructBase(i: I) = *SubObj;
7356	}
7357	}
7358
7359	// Visit the fields.
7360	unsigned FieldIdx = 0;
7361	for (FieldDecl *FD : RD->fields()) {
7362	// FIXME: We don't currently support bit-fields. A lot of the logic for
7363	// this is in CodeGen, so we need to factor it around.
7364	if (FD->isBitField()) {
7365	Info.FFDiag(BCE->getBeginLoc(),
7366	diag::note_constexpr_bit_cast_unsupported_bitfield);
7367	return std::nullopt;
7368	}
7369
7370	uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
7371	assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0);
7372
7373	CharUnits FieldOffset =
7374	CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) +
7375	Offset;
7376	QualType FieldTy = FD->getType();
7377	std::optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
7378	if (!SubObj)
7379	return std::nullopt;
7380	ResultVal.getStructField(FieldIdx) = *SubObj;
7381	++FieldIdx;
7382	}
7383
7384	return ResultVal;
7385	}
7386
7387	std::optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
7388	QualType RepresentationType = Ty->getDecl()->getIntegerType();
7389	assert(!RepresentationType.isNull() &&
7390	"enum forward decl should be caught by Sema");
7391	const auto *AsBuiltin =
7392	RepresentationType.getCanonicalType()->castAs<BuiltinType>();
7393	// Recurse into the underlying type. Treat std::byte transparently as
7394	// unsigned char.
7395	return visit(AsBuiltin, Offset, /*EnumTy=*/Ty);
7396	}
7397
7398	std::optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
7399	size_t Size = Ty->getLimitedSize();
7400	CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());
7401
7402	APValue ArrayValue(APValue::UninitArray(), Size, Size);
7403	for (size_t I = 0; I != Size; ++I) {
7404	std::optional<APValue> ElementValue =
7405	visitType(Ty->getElementType(), Offset + I * ElementWidth);
7406	if (!ElementValue)
7407	return std::nullopt;
7408	ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
7409	}
7410
7411	return ArrayValue;
7412	}
7413
7414	std::optional<APValue> visit(const VectorType *VTy, CharUnits Offset) {
7415	QualType EltTy = VTy->getElementType();
7416	unsigned NElts = VTy->getNumElements();
7417	unsigned EltSize =
7418	VTy->isExtVectorBoolType() ? 1 : Info.Ctx.getTypeSize(T: EltTy);
7419
7420	if ((NElts * EltSize) % Info.Ctx.getCharWidth() != 0) {
7421	// The vector's size in bits is not a multiple of the target's byte size,
7422	// so its layout is unspecified. For now, we'll simply treat these cases
7423	// as unsupported (this should only be possible with OpenCL bool vectors
7424	// whose element count isn't a multiple of the byte size).
7425	Info.FFDiag(BCE->getBeginLoc(),
7426	diag::note_constexpr_bit_cast_invalid_vector)
7427	<< QualType(VTy, 0) << EltSize << NElts << Info.Ctx.getCharWidth();
7428	return std::nullopt;
7429	}
7430
7431	if (EltTy->isRealFloatingType() && &Info.Ctx.getFloatTypeSemantics(T: EltTy) ==
7432	&APFloat::x87DoubleExtended()) {
7433	// The layout for x86_fp80 vectors seems to be handled very inconsistently
7434	// by both clang and LLVM, so for now we won't allow bit_casts involving
7435	// it in a constexpr context.
7436	Info.FFDiag(BCE->getBeginLoc(),
7437	diag::note_constexpr_bit_cast_unsupported_type)
7438	<< EltTy;
7439	return std::nullopt;
7440	}
7441
7442	SmallVector<APValue, 4> Elts;
7443	Elts.reserve(N: NElts);
7444	if (VTy->isExtVectorBoolType()) {
7445	// Special handling for OpenCL bool vectors:
7446	// Since these vectors are stored as packed bits, but we can't read
7447	// individual bits from the BitCastBuffer, we'll buffer all of the
7448	// elements together into an appropriately sized APInt and write them all
7449	// out at once. Because we don't accept vectors where NElts * EltSize
7450	// isn't a multiple of the char size, there will be no padding space, so
7451	// we don't have to worry about reading any padding data which didn't
7452	// actually need to be accessed.
7453	bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
7454
7455	SmallVector<uint8_t, 8> Bytes;
7456	Bytes.reserve(N: NElts / 8);
7457	if (!Buffer.readObject(Offset, Width: CharUnits::fromQuantity(Quantity: NElts / 8), Output&: Bytes))
7458	return std::nullopt;
7459
7460	APSInt SValInt(NElts, true);
7461	llvm::LoadIntFromMemory(IntVal&: SValInt, Src: &*Bytes.begin(), LoadBytes: Bytes.size());
7462
7463	for (unsigned I = 0; I < NElts; ++I) {
7464	llvm::APInt Elt =
7465	SValInt.extractBits(numBits: 1, bitPosition: (BigEndian ? NElts - I - 1 : I) * EltSize);
7466	Elts.emplace_back(
7467	APSInt(std::move(Elt), !EltTy->isSignedIntegerType()));
7468	}
7469	} else {
7470	// Iterate over each of the elements and read them from the buffer at
7471	// the appropriate offset.
7472	CharUnits EltSizeChars = Info.Ctx.getTypeSizeInChars(T: EltTy);
7473	for (unsigned I = 0; I < NElts; ++I) {
7474	std::optional<APValue> EltValue =
7475	visitType(EltTy, Offset + I * EltSizeChars);
7476	if (!EltValue)
7477	return std::nullopt;
7478	Elts.push_back(std::move(*EltValue));
7479	}
7480	}
7481
7482	return APValue(Elts.data(), Elts.size());
7483	}
7484
7485	std::optional<APValue> visit(const Type *Ty, CharUnits Offset) {
7486	return unsupportedType(Ty: QualType(Ty, 0));
7487	}
7488
7489	std::optional<APValue> visitType(QualType Ty, CharUnits Offset) {
7490	QualType Can = Ty.getCanonicalType();
7491
7492	switch (Can->getTypeClass()) {
7493	#define TYPE(Class, Base) \
7494	case Type::Class: \
7495	return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
7496	#define ABSTRACT_TYPE(Class, Base)
7497	#define NON_CANONICAL_TYPE(Class, Base) \
7498	case Type::Class: \
7499	llvm_unreachable("non-canonical type should be impossible!");
7500	#define DEPENDENT_TYPE(Class, Base) \
7501	case Type::Class: \
7502	llvm_unreachable( \
7503	"dependent types aren't supported in the constant evaluator!");
7504	#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \
7505	case Type::Class: \
7506	llvm_unreachable("either dependent or not canonical!");
7507	#include "clang/AST/TypeNodes.inc"
7508	}
7509	llvm_unreachable("Unhandled Type::TypeClass");
7510	}
7511
7512	public:
7513	// Pull out a full value of type DstType.
7514	static std::optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
7515	const CastExpr *BCE) {
7516	BufferToAPValueConverter Converter(Info, Buffer, BCE);
7517	return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(Quantity: 0));
7518	}
7519	};
7520
7521	static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
7522	QualType Ty, EvalInfo *Info,
7523	const ASTContext &Ctx,
7524	bool CheckingDest) {
7525	Ty = Ty.getCanonicalType();
7526
7527	auto diag = [&](int Reason) {
7528	if (Info)
7529	Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
7530	<< CheckingDest << (Reason == 4) << Reason;
7531	return false;
7532	};
7533	auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
7534	if (Info)
7535	Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
7536	<< NoteTy << Construct << Ty;
7537	return false;
7538	};
7539
7540	if (Ty->isUnionType())
7541	return diag(0);
7542	if (Ty->isPointerType())
7543	return diag(1);
7544	if (Ty->isMemberPointerType())
7545	return diag(2);
7546	if (Ty.isVolatileQualified())
7547	return diag(3);
7548
7549	if (RecordDecl *Record = Ty->getAsRecordDecl()) {
7550	if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
7551	for (CXXBaseSpecifier &BS : CXXRD->bases())
7552	if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx,
7553	CheckingDest))
7554	return note(1, BS.getType(), BS.getBeginLoc());
7555	}
7556	for (FieldDecl *FD : Record->fields()) {
7557	if (FD->getType()->isReferenceType())
7558	return diag(4);
7559	if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx,
7560	CheckingDest))
7561	return note(0, FD->getType(), FD->getBeginLoc());
7562	}
7563	}
7564
7565	if (Ty->isArrayType() &&
7566	!checkBitCastConstexprEligibilityType(Loc, Ty: Ctx.getBaseElementType(QT: Ty),
7567	Info, Ctx, CheckingDest))
7568	return false;
7569
7570	return true;
7571	}
7572
7573	static bool checkBitCastConstexprEligibility(EvalInfo *Info,
7574	const ASTContext &Ctx,
7575	const CastExpr *BCE) {
7576	bool DestOK = checkBitCastConstexprEligibilityType(
7577	BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true);
7578	bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
7579	BCE->getBeginLoc(),
7580	BCE->getSubExpr()->getType(), Info, Ctx, false);
7581	return SourceOK;
7582	}
7583
7584	static bool handleRValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7585	const APValue &SourceRValue,
7586	const CastExpr *BCE) {
7587	assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
7588	"no host or target supports non 8-bit chars");
7589
7590	if (!checkBitCastConstexprEligibility(Info: &Info, Ctx: Info.Ctx, BCE))
7591	return false;
7592
7593	// Read out SourceValue into a char buffer.
7594	std::optional<BitCastBuffer> Buffer =
7595	APValueToBufferConverter::convert(Info, Src: SourceRValue, BCE);
7596	if (!Buffer)
7597	return false;
7598
7599	// Write out the buffer into a new APValue.
7600	std::optional<APValue> MaybeDestValue =
7601	BufferToAPValueConverter::convert(Info, *Buffer, BCE);
7602	if (!MaybeDestValue)
7603	return false;
7604
7605	DestValue = std::move(*MaybeDestValue);
7606	return true;
7607	}
7608
7609	static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7610	APValue &SourceValue,
7611	const CastExpr *BCE) {
7612	assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
7613	"no host or target supports non 8-bit chars");
7614	assert(SourceValue.isLValue() &&
7615	"LValueToRValueBitcast requires an lvalue operand!");
7616
7617	LValue SourceLValue;
7618	APValue SourceRValue;
7619	SourceLValue.setFrom(Ctx&: Info.Ctx, V: SourceValue);
7620	if (!handleLValueToRValueConversion(
7621	Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue,
7622	SourceRValue, /*WantObjectRepresentation=*/true))
7623	return false;
7624
7625	return handleRValueToRValueBitCast(Info, DestValue, SourceRValue, BCE);
7626	}
7627
7628	template <class Derived>
7629	class ExprEvaluatorBase
7630	: public ConstStmtVisitor<Derived, bool> {
7631	private:
7632	Derived &getDerived() { return static_cast<Derived&>(*this); }
7633	bool DerivedSuccess(const APValue &V, const Expr *E) {
7634	return getDerived().Success(V, E);
7635	}
7636	bool DerivedZeroInitialization(const Expr *E) {
7637	return getDerived().ZeroInitialization(E);
7638	}
7639
7640	// Check whether a conditional operator with a non-constant condition is a
7641	// potential constant expression. If neither arm is a potential constant
7642	// expression, then the conditional operator is not either.
7643	template<typename ConditionalOperator>
7644	void CheckPotentialConstantConditional(const ConditionalOperator *E) {
7645	assert(Info.checkingPotentialConstantExpression());
7646
7647	// Speculatively evaluate both arms.
7648	SmallVector<PartialDiagnosticAt, 8> Diag;
7649	{
7650	SpeculativeEvaluationRAII Speculate(Info, &Diag);
7651	StmtVisitorTy::Visit(E->getFalseExpr());
7652	if (Diag.empty())
7653	return;
7654	}
7655
7656	{
7657	SpeculativeEvaluationRAII Speculate(Info, &Diag);
7658	Diag.clear();
7659	StmtVisitorTy::Visit(E->getTrueExpr());
7660	if (Diag.empty())
7661	return;
7662	}
7663
7664	Error(E, diag::note_constexpr_conditional_never_const);
7665	}
7666
7667
7668	template<typename ConditionalOperator>
7669	bool HandleConditionalOperator(const ConditionalOperator *E) {
7670	bool BoolResult;
7671	if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
7672	if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
7673	CheckPotentialConstantConditional(E);
7674	return false;
7675	}
7676	if (Info.noteFailure()) {
7677	StmtVisitorTy::Visit(E->getTrueExpr());
7678	StmtVisitorTy::Visit(E->getFalseExpr());
7679	}
7680	return false;
7681	}
7682
7683	Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
7684	return StmtVisitorTy::Visit(EvalExpr);
7685	}
7686
7687	protected:
7688	EvalInfo &Info;
7689	typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
7690	typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
7691
7692	OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
7693	return Info.CCEDiag(E, DiagId: D);
7694	}
7695
7696	bool ZeroInitialization(const Expr *E) { return Error(E); }
7697
7698	bool IsConstantEvaluatedBuiltinCall(const CallExpr *E) {
7699	unsigned BuiltinOp = E->getBuiltinCallee();
7700	return BuiltinOp != 0 &&
7701	Info.Ctx.BuiltinInfo.isConstantEvaluated(ID: BuiltinOp);
7702	}
7703
7704	public:
7705	ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
7706
7707	EvalInfo &getEvalInfo() { return Info; }
7708
7709	/// Report an evaluation error. This should only be called when an error is
7710	/// first discovered. When propagating an error, just return false.
7711	bool Error(const Expr *E, diag::kind D) {
7712	Info.FFDiag(E, DiagId: D) << E->getSourceRange();
7713	return false;
7714	}
7715	bool Error(const Expr *E) {
7716	return Error(E, diag::note_invalid_subexpr_in_const_expr);
7717	}
7718
7719	bool VisitStmt(const Stmt *) {
7720	llvm_unreachable("Expression evaluator should not be called on stmts");
7721	}
7722	bool VisitExpr(const Expr *E) {
7723	return Error(E);
7724	}
7725
7726	bool VisitPredefinedExpr(const PredefinedExpr *E) {
7727	return StmtVisitorTy::Visit(E->getFunctionName());
7728	}
7729	bool VisitConstantExpr(const ConstantExpr *E) {
7730	if (E->hasAPValueResult())
7731	return DerivedSuccess(V: E->getAPValueResult(), E);
7732
7733	return StmtVisitorTy::Visit(E->getSubExpr());
7734	}
7735
7736	bool VisitParenExpr(const ParenExpr *E)
7737	{ return StmtVisitorTy::Visit(E->getSubExpr()); }
7738	bool VisitUnaryExtension(const UnaryOperator *E)
7739	{ return StmtVisitorTy::Visit(E->getSubExpr()); }
7740	bool VisitUnaryPlus(const UnaryOperator *E)
7741	{ return StmtVisitorTy::Visit(E->getSubExpr()); }
7742	bool VisitChooseExpr(const ChooseExpr *E)
7743	{ return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
7744	bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
7745	{ return StmtVisitorTy::Visit(E->getResultExpr()); }
7746	bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
7747	{ return StmtVisitorTy::Visit(E->getReplacement()); }
7748	bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
7749	TempVersionRAII RAII(*Info.CurrentCall);
7750	SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7751	return StmtVisitorTy::Visit(E->getExpr());
7752	}
7753	bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
7754	TempVersionRAII RAII(*Info.CurrentCall);
7755	// The initializer may not have been parsed yet, or might be erroneous.
7756	if (!E->getExpr())
7757	return Error(E);
7758	SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7759	return StmtVisitorTy::Visit(E->getExpr());
7760	}
7761
7762	bool VisitExprWithCleanups(const ExprWithCleanups *E) {
7763	FullExpressionRAII Scope(Info);
7764	return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
7765	}
7766
7767	// Temporaries are registered when created, so we don't care about
7768	// CXXBindTemporaryExpr.
7769	bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
7770	return StmtVisitorTy::Visit(E->getSubExpr());
7771	}
7772
7773	bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
7774	CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
7775	return static_cast<Derived*>(this)->VisitCastExpr(E);
7776	}
7777	bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
7778	if (!Info.Ctx.getLangOpts().CPlusPlus20)
7779	CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
7780	return static_cast<Derived*>(this)->VisitCastExpr(E);
7781	}
7782	bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
7783	return static_cast<Derived*>(this)->VisitCastExpr(E);
7784	}
7785
7786	bool VisitBinaryOperator(const BinaryOperator *E) {
7787	switch (E->getOpcode()) {
7788	default:
7789	return Error(E);
7790
7791	case BO_Comma:
7792	VisitIgnoredValue(E: E->getLHS());
7793	return StmtVisitorTy::Visit(E->getRHS());
7794
7795	case BO_PtrMemD:
7796	case BO_PtrMemI: {
7797	LValue Obj;
7798	if (!HandleMemberPointerAccess(Info, BO: E, LV&: Obj))
7799	return false;
7800	APValue Result;
7801	if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
7802	return false;
7803	return DerivedSuccess(V: Result, E);
7804	}
7805	}
7806	}
7807
7808	bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
7809	return StmtVisitorTy::Visit(E->getSemanticForm());
7810	}
7811
7812	bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
7813	// Evaluate and cache the common expression. We treat it as a temporary,
7814	// even though it's not quite the same thing.
7815	LValue CommonLV;
7816	if (!Evaluate(Result&: Info.CurrentCall->createTemporary(
7817	E->getOpaqueValue(),
7818	getStorageType(Info.Ctx, E->getOpaqueValue()),
7819	ScopeKind::FullExpression, CommonLV),
7820	Info, E: E->getCommon()))
7821	return false;
7822
7823	return HandleConditionalOperator(E);
7824	}
7825
7826	bool VisitConditionalOperator(const ConditionalOperator *E) {
7827	bool IsBcpCall = false;
7828	// If the condition (ignoring parens) is a __builtin_constant_p call,
7829	// the result is a constant expression if it can be folded without
7830	// side-effects. This is an important GNU extension. See GCC PR38377
7831	// for discussion.
7832	if (const CallExpr *CallCE =
7833	dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
7834	if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
7835	IsBcpCall = true;
7836
7837	// Always assume __builtin_constant_p(...) ? ... : ... is a potential
7838	// constant expression; we can't check whether it's potentially foldable.
7839	// FIXME: We should instead treat __builtin_constant_p as non-constant if
7840	// it would return 'false' in this mode.
7841	if (Info.checkingPotentialConstantExpression() && IsBcpCall)
7842	return false;
7843
7844	FoldConstant Fold(Info, IsBcpCall);
7845	if (!HandleConditionalOperator(E)) {
7846	Fold.keepDiagnostics();
7847	return false;
7848	}
7849
7850	return true;
7851	}
7852
7853	bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
7854	if (APValue *Value = Info.CurrentCall->getCurrentTemporary(Key: E);
7855	Value && !Value->isAbsent())
7856	return DerivedSuccess(V: *Value, E);
7857
7858	const Expr *Source = E->getSourceExpr();
7859	if (!Source)
7860	return Error(E);
7861	if (Source == E) {
7862	assert(0 && "OpaqueValueExpr recursively refers to itself");
7863	return Error(E);
7864	}
7865	return StmtVisitorTy::Visit(Source);
7866	}
7867
7868	bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
7869	for (const Expr *SemE : E->semantics()) {
7870	if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
7871	// FIXME: We can't handle the case where an OpaqueValueExpr is also the
7872	// result expression: there could be two different LValues that would
7873	// refer to the same object in that case, and we can't model that.
7874	if (SemE == E->getResultExpr())
7875	return Error(E);
7876
7877	// Unique OVEs get evaluated if and when we encounter them when
7878	// emitting the rest of the semantic form, rather than eagerly.
7879	if (OVE->isUnique())
7880	continue;
7881
7882	LValue LV;
7883	if (!Evaluate(Info.CurrentCall->createTemporary(
7884	OVE, getStorageType(Info.Ctx, OVE),
7885	ScopeKind::FullExpression, LV),
7886	Info, OVE->getSourceExpr()))
7887	return false;
7888	} else if (SemE == E->getResultExpr()) {
7889	if (!StmtVisitorTy::Visit(SemE))
7890	return false;
7891	} else {
7892	if (!EvaluateIgnoredValue(Info, E: SemE))
7893	return false;
7894	}
7895	}
7896	return true;
7897	}
7898
7899	bool VisitCallExpr(const CallExpr *E) {
7900	APValue Result;
7901	if (!handleCallExpr(E, Result, ResultSlot: nullptr))
7902	return false;
7903	return DerivedSuccess(V: Result, E);
7904	}
7905
7906	bool handleCallExpr(const CallExpr *E, APValue &Result,
7907	const LValue *ResultSlot) {
7908	CallScopeRAII CallScope(Info);
7909
7910	const Expr *Callee = E->getCallee()->IgnoreParens();
7911	QualType CalleeType = Callee->getType();
7912
7913	const FunctionDecl *FD = nullptr;
7914	LValue *This = nullptr, ThisVal;
7915	auto Args = llvm::ArrayRef(E->getArgs(), E->getNumArgs());
7916	bool HasQualifier = false;
7917
7918	CallRef Call;
7919
7920	// Extract function decl and 'this' pointer from the callee.
7921	if (CalleeType->isSpecificBuiltinType(K: BuiltinType::BoundMember)) {
7922	const CXXMethodDecl *Member = nullptr;
7923	if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
7924	// Explicit bound member calls, such as x.f() or p->g();
7925	if (!EvaluateObjectArgument(Info, Object: ME->getBase(), This&: ThisVal))
7926	return false;
7927	Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
7928	if (!Member)
7929	return Error(Callee);
7930	This = &ThisVal;
7931	HasQualifier = ME->hasQualifier();
7932	} else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
7933	// Indirect bound member calls ('.*' or '->*').
7934	const ValueDecl *D =
7935	HandleMemberPointerAccess(Info, BO: BE, LV&: ThisVal, IncludeMember: false);
7936	if (!D)
7937	return false;
7938	Member = dyn_cast<CXXMethodDecl>(D);
7939	if (!Member)
7940	return Error(Callee);
7941	This = &ThisVal;
7942	} else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
7943	if (!Info.getLangOpts().CPlusPlus20)
7944	Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
7945	return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
7946	HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType());
7947	} else
7948	return Error(Callee);
7949	FD = Member;
7950	} else if (CalleeType->isFunctionPointerType()) {
7951	LValue CalleeLV;
7952	if (!EvaluatePointer(E: Callee, Result&: CalleeLV, Info))
7953	return false;
7954
7955	if (!CalleeLV.getLValueOffset().isZero())
7956	return Error(Callee);
7957	if (CalleeLV.isNullPointer()) {
7958	Info.FFDiag(Callee, diag::note_constexpr_null_callee)
7959	<< const_cast<Expr *>(Callee);
7960	return false;
7961	}
7962	FD = dyn_cast_or_null<FunctionDecl>(
7963	CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>());
7964	if (!FD)
7965	return Error(Callee);
7966	// Don't call function pointers which have been cast to some other type.
7967	// Per DR (no number yet), the caller and callee can differ in noexcept.
7968	if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
7969	T: CalleeType->getPointeeType(), U: FD->getType())) {
7970	return Error(E);
7971	}
7972
7973	// For an (overloaded) assignment expression, evaluate the RHS before the
7974	// LHS.
7975	auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
7976	if (OCE && OCE->isAssignmentOp()) {
7977	assert(Args.size() == 2 && "wrong number of arguments in assignment");
7978	Call = Info.CurrentCall->createCall(Callee: FD);
7979	bool HasThis = false;
7980	if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
7981	HasThis = MD->isImplicitObjectMemberFunction();
7982	if (!EvaluateArgs(HasThis ? Args.slice(1) : Args, Call, Info, FD,
7983	/*RightToLeft=*/true))
7984	return false;
7985	}
7986
7987	// Overloaded operator calls to member functions are represented as normal
7988	// calls with '*this' as the first argument.
7989	const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
7990	if (MD &&
7991	(MD->isImplicitObjectMemberFunction() || (OCE && MD->isStatic()))) {
7992	// FIXME: When selecting an implicit conversion for an overloaded
7993	// operator delete, we sometimes try to evaluate calls to conversion
7994	// operators without a 'this' parameter!
7995	if (Args.empty())
7996	return Error(E);
7997
7998	if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
7999	return false;
8000
8001	// If we are calling a static operator, the 'this' argument needs to be
8002	// ignored after being evaluated.
8003	if (MD->isInstance())
8004	This = &ThisVal;
8005
8006	// If this is syntactically a simple assignment using a trivial
8007	// assignment operator, start the lifetimes of union members as needed,
8008	// per C++20 [class.union]5.
8009	if (Info.getLangOpts().CPlusPlus20 && OCE &&
8010	OCE->getOperator() == OO_Equal && MD->isTrivial() &&
8011	!MaybeHandleUnionActiveMemberChange(Info, Args[0], ThisVal))
8012	return false;
8013
8014	Args = Args.slice(1);
8015	} else if (MD && MD->isLambdaStaticInvoker()) {
8016	// Map the static invoker for the lambda back to the call operator.
8017	// Conveniently, we don't have to slice out the 'this' argument (as is
8018	// being done for the non-static case), since a static member function
8019	// doesn't have an implicit argument passed in.
8020	const CXXRecordDecl *ClosureClass = MD->getParent();
8021	assert(
8022	ClosureClass->captures_begin() == ClosureClass->captures_end() &&
8023	"Number of captures must be zero for conversion to function-ptr");
8024
8025	const CXXMethodDecl *LambdaCallOp =
8026	ClosureClass->getLambdaCallOperator();
8027
8028	// Set 'FD', the function that will be called below, to the call
8029	// operator. If the closure object represents a generic lambda, find
8030	// the corresponding specialization of the call operator.
8031
8032	if (ClosureClass->isGenericLambda()) {
8033	assert(MD->isFunctionTemplateSpecialization() &&
8034	"A generic lambda's static-invoker function must be a "
8035	"template specialization");
8036	const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
8037	FunctionTemplateDecl *CallOpTemplate =
8038	LambdaCallOp->getDescribedFunctionTemplate();
8039	void *InsertPos = nullptr;
8040	FunctionDecl *CorrespondingCallOpSpecialization =
8041	CallOpTemplate->findSpecialization(Args: TAL->asArray(), InsertPos);
8042	assert(CorrespondingCallOpSpecialization &&
8043	"We must always have a function call operator specialization "
8044	"that corresponds to our static invoker specialization");
8045	assert(isa<CXXMethodDecl>(CorrespondingCallOpSpecialization));
8046	FD = CorrespondingCallOpSpecialization;
8047	} else
8048	FD = LambdaCallOp;
8049	} else if (FD->isReplaceableGlobalAllocationFunction()) {
8050	if (FD->getDeclName().getCXXOverloadedOperator() == OO_New ||
8051	FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) {
8052	LValue Ptr;
8053	if (!HandleOperatorNewCall(Info, E, Result&: Ptr))
8054	return false;
8055	Ptr.moveInto(V&: Result);
8056	return CallScope.destroy();
8057	} else {
8058	return HandleOperatorDeleteCall(Info, E) && CallScope.destroy();
8059	}
8060	}
8061	} else
8062	return Error(E);
8063
8064	// Evaluate the arguments now if we've not already done so.
8065	if (!Call) {
8066	Call = Info.CurrentCall->createCall(Callee: FD);
8067	if (!EvaluateArgs(Args, Call, Info, FD))
8068	return false;
8069	}
8070
8071	SmallVector<QualType, 4> CovariantAdjustmentPath;
8072	if (This) {
8073	auto *NamedMember = dyn_cast<CXXMethodDecl>(FD);
8074	if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
8075	// Perform virtual dispatch, if necessary.
8076	FD = HandleVirtualDispatch(Info, E, *This, NamedMember,
8077	CovariantAdjustmentPath);
8078	if (!FD)
8079	return false;
8080	} else if (NamedMember && NamedMember->isImplicitObjectMemberFunction()) {
8081	// Check that the 'this' pointer points to an object of the right type.
8082	// FIXME: If this is an assignment operator call, we may need to change
8083	// the active union member before we check this.
8084	if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember))
8085	return false;
8086	}
8087	}
8088
8089	// Destructor calls are different enough that they have their own codepath.
8090	if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) {
8091	assert(This && "no 'this' pointer for destructor call");
8092	return HandleDestruction(Info, E, *This,
8093	Info.Ctx.getRecordType(Decl: DD->getParent())) &&
8094	CallScope.destroy();
8095	}
8096
8097	const FunctionDecl *Definition = nullptr;
8098	Stmt *Body = FD->getBody(Definition);
8099
8100	if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
8101	!HandleFunctionCall(E->getExprLoc(), Definition, This, E, Args, Call,
8102	Body, Info, Result, ResultSlot))
8103	return false;
8104
8105	if (!CovariantAdjustmentPath.empty() &&
8106	!HandleCovariantReturnAdjustment(Info, E, Result,
8107	CovariantAdjustmentPath))
8108	return false;
8109
8110	return CallScope.destroy();
8111	}
8112
8113	bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
8114	return StmtVisitorTy::Visit(E->getInitializer());
8115	}
8116	bool VisitInitListExpr(const InitListExpr *E) {
8117	if (E->getNumInits() == 0)
8118	return DerivedZeroInitialization(E);
8119	if (E->getNumInits() == 1)
8120	return StmtVisitorTy::Visit(E->getInit(Init: 0));
8121	return Error(E);
8122	}
8123	bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
8124	return DerivedZeroInitialization(E);
8125	}
8126	bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
8127	return DerivedZeroInitialization(E);
8128	}
8129	bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
8130	return DerivedZeroInitialization(E);
8131	}
8132
8133	/// A member expression where the object is a prvalue is itself a prvalue.
8134	bool VisitMemberExpr(const MemberExpr *E) {
8135	assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&
8136	"missing temporary materialization conversion");
8137	assert(!E->isArrow() && "missing call to bound member function?");
8138
8139	APValue Val;
8140	if (!Evaluate(Result&: Val, Info, E: E->getBase()))
8141	return false;
8142
8143	QualType BaseTy = E->getBase()->getType();
8144
8145	const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
8146	if (!FD) return Error(E);
8147	assert(!FD->getType()->isReferenceType() && "prvalue reference?");
8148	assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
8149	FD->getParent()->getCanonicalDecl() && "record / field mismatch");
8150
8151	// Note: there is no lvalue base here. But this case should only ever
8152	// happen in C or in C++98, where we cannot be evaluating a constexpr
8153	// constructor, which is the only case the base matters.
8154	CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
8155	SubobjectDesignator Designator(BaseTy);
8156	Designator.addDeclUnchecked(FD);
8157
8158	APValue Result;
8159	return extractSubobject(Info, E, Obj, Designator, Result) &&
8160	DerivedSuccess(V: Result, E);
8161	}
8162
8163	bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
8164	APValue Val;
8165	if (!Evaluate(Result&: Val, Info, E: E->getBase()))
8166	return false;
8167
8168	if (Val.isVector()) {
8169	SmallVector<uint32_t, 4> Indices;
8170	E->getEncodedElementAccess(Elts&: Indices);
8171	if (Indices.size() == 1) {
8172	// Return scalar.
8173	return DerivedSuccess(V: Val.getVectorElt(I: Indices[0]), E);
8174	} else {
8175	// Construct new APValue vector.
8176	SmallVector<APValue, 4> Elts;
8177	for (unsigned I = 0; I < Indices.size(); ++I) {
8178	Elts.push_back(Elt: Val.getVectorElt(I: Indices[I]));
8179	}
8180	APValue VecResult(Elts.data(), Indices.size());
8181	return DerivedSuccess(V: VecResult, E);
8182	}
8183	}
8184
8185	return false;
8186	}
8187
8188	bool VisitCastExpr(const CastExpr *E) {
8189	switch (E->getCastKind()) {
8190	default:
8191	break;
8192
8193	case CK_AtomicToNonAtomic: {
8194	APValue AtomicVal;
8195	// This does not need to be done in place even for class/array types:
8196	// atomic-to-non-atomic conversion implies copying the object
8197	// representation.
8198	if (!Evaluate(Result&: AtomicVal, Info, E: E->getSubExpr()))
8199	return false;
8200	return DerivedSuccess(V: AtomicVal, E);
8201	}
8202
8203	case CK_NoOp:
8204	case CK_UserDefinedConversion:
8205	return StmtVisitorTy::Visit(E->getSubExpr());
8206
8207	case CK_LValueToRValue: {
8208	LValue LVal;
8209	if (!EvaluateLValue(E: E->getSubExpr(), Result&: LVal, Info))
8210	return false;
8211	APValue RVal;
8212	// Note, we use the subexpression's type in order to retain cv-qualifiers.
8213	if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
8214	LVal, RVal))
8215	return false;
8216	return DerivedSuccess(V: RVal, E);
8217	}
8218	case CK_LValueToRValueBitCast: {
8219	APValue DestValue, SourceValue;
8220	if (!Evaluate(Result&: SourceValue, Info, E: E->getSubExpr()))
8221	return false;
8222	if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, BCE: E))
8223	return false;
8224	return DerivedSuccess(V: DestValue, E);
8225	}
8226
8227	case CK_AddressSpaceConversion: {
8228	APValue Value;
8229	if (!Evaluate(Result&: Value, Info, E: E->getSubExpr()))
8230	return false;
8231	return DerivedSuccess(V: Value, E);
8232	}
8233	}
8234
8235	return Error(E);
8236	}
8237
8238	bool VisitUnaryPostInc(const UnaryOperator *UO) {
8239	return VisitUnaryPostIncDec(UO);
8240	}
8241	bool VisitUnaryPostDec(const UnaryOperator *UO) {
8242	return VisitUnaryPostIncDec(UO);
8243	}
8244	bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
8245	if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8246	return Error(UO);
8247
8248	LValue LVal;
8249	if (!EvaluateLValue(E: UO->getSubExpr(), Result&: LVal, Info))
8250	return false;
8251	APValue RVal;
8252	if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
8253	UO->isIncrementOp(), &RVal))
8254	return false;
8255	return DerivedSuccess(V: RVal, E: UO);
8256	}
8257
8258	bool VisitStmtExpr(const StmtExpr *E) {
8259	// We will have checked the full-expressions inside the statement expression
8260	// when they were completed, and don't need to check them again now.
8261	llvm::SaveAndRestore NotCheckingForUB(Info.CheckingForUndefinedBehavior,
8262	false);
8263
8264	const CompoundStmt *CS = E->getSubStmt();
8265	if (CS->body_empty())
8266	return true;
8267
8268	BlockScopeRAII Scope(Info);
8269	for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
8270	BE = CS->body_end();
8271	/**/; ++BI) {
8272	if (BI + 1 == BE) {
8273	const Expr *FinalExpr = dyn_cast<Expr>(*BI);
8274	if (!FinalExpr) {
8275	Info.FFDiag((*BI)->getBeginLoc(),
8276	diag::note_constexpr_stmt_expr_unsupported);
8277	return false;
8278	}
8279	return this->Visit(FinalExpr) && Scope.destroy();
8280	}
8281
8282	APValue ReturnValue;
8283	StmtResult Result = { .Value: ReturnValue, .Slot: nullptr };
8284	EvalStmtResult ESR = EvaluateStmt(Result, Info, S: *BI);
8285	if (ESR != ESR_Succeeded) {
8286	// FIXME: If the statement-expression terminated due to 'return',
8287	// 'break', or 'continue', it would be nice to propagate that to
8288	// the outer statement evaluation rather than bailing out.
8289	if (ESR != ESR_Failed)
8290	Info.FFDiag((*BI)->getBeginLoc(),
8291	diag::note_constexpr_stmt_expr_unsupported);
8292	return false;
8293	}
8294	}
8295
8296	llvm_unreachable("Return from function from the loop above.");
8297	}
8298
8299	bool VisitPackIndexingExpr(const PackIndexingExpr *E) {
8300	return StmtVisitorTy::Visit(E->getSelectedExpr());
8301	}
8302
8303	/// Visit a value which is evaluated, but whose value is ignored.
8304	void VisitIgnoredValue(const Expr *E) {
8305	EvaluateIgnoredValue(Info, E);
8306	}
8307
8308	/// Potentially visit a MemberExpr's base expression.
8309	void VisitIgnoredBaseExpression(const Expr *E) {
8310	// While MSVC doesn't evaluate the base expression, it does diagnose the
8311	// presence of side-effecting behavior.
8312	if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Ctx: Info.Ctx))
8313	return;
8314	VisitIgnoredValue(E);
8315	}
8316	};
8317
8318	} // namespace
8319
8320	//===----------------------------------------------------------------------===//
8321	// Common base class for lvalue and temporary evaluation.
8322	//===----------------------------------------------------------------------===//
8323	namespace {
8324	template<class Derived>
8325	class LValueExprEvaluatorBase
8326	: public ExprEvaluatorBase<Derived> {
8327	protected:
8328	LValue &Result;
8329	bool InvalidBaseOK;
8330	typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
8331	typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
8332
8333	bool Success(APValue::LValueBase B) {
8334	Result.set(B);
8335	return true;
8336	}
8337
8338	bool evaluatePointer(const Expr *E, LValue &Result) {
8339	return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
8340	}
8341
8342	public:
8343	LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
8344	: ExprEvaluatorBaseTy(Info), Result(Result),
8345	InvalidBaseOK(InvalidBaseOK) {}
8346
8347	bool Success(const APValue &V, const Expr *E) {
8348	Result.setFrom(Ctx&: this->Info.Ctx, V);
8349	return true;
8350	}
8351
8352	bool VisitMemberExpr(const MemberExpr *E) {
8353	// Handle non-static data members.
8354	QualType BaseTy;
8355	bool EvalOK;
8356	if (E->isArrow()) {
8357	EvalOK = evaluatePointer(E: E->getBase(), Result);
8358	BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
8359	} else if (E->getBase()->isPRValue()) {
8360	assert(E->getBase()->getType()->isRecordType());
8361	EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
8362	BaseTy = E->getBase()->getType();
8363	} else {
8364	EvalOK = this->Visit(E->getBase());
8365	BaseTy = E->getBase()->getType();
8366	}
8367	if (!EvalOK) {
8368	if (!InvalidBaseOK)
8369	return false;
8370	Result.setInvalid(E);
8371	return true;
8372	}
8373
8374	const ValueDecl *MD = E->getMemberDecl();
8375	if (const FieldDecl *FD = dyn_cast<FieldDecl>(Val: E->getMemberDecl())) {
8376	assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
8377	FD->getParent()->getCanonicalDecl() && "record / field mismatch");
8378	(void)BaseTy;
8379	if (!HandleLValueMember(this->Info, E, Result, FD))
8380	return false;
8381	} else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(Val: MD)) {
8382	if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
8383	return false;
8384	} else
8385	return this->Error(E);
8386
8387	if (MD->getType()->isReferenceType()) {
8388	APValue RefValue;
8389	if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
8390	RefValue))
8391	return false;
8392	return Success(RefValue, E);
8393	}
8394	return true;
8395	}
8396
8397	bool VisitBinaryOperator(const BinaryOperator *E) {
8398	switch (E->getOpcode()) {
8399	default:
8400	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8401
8402	case BO_PtrMemD:
8403	case BO_PtrMemI:
8404	return HandleMemberPointerAccess(this->Info, E, Result);
8405	}
8406	}
8407
8408	bool VisitCastExpr(const CastExpr *E) {
8409	switch (E->getCastKind()) {
8410	default:
8411	return ExprEvaluatorBaseTy::VisitCastExpr(E);
8412
8413	case CK_DerivedToBase:
8414	case CK_UncheckedDerivedToBase:
8415	if (!this->Visit(E->getSubExpr()))
8416	return false;
8417
8418	// Now figure out the necessary offset to add to the base LV to get from
8419	// the derived class to the base class.
8420	return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
8421	Result);
8422	}
8423	}
8424	};
8425	}
8426
8427	//===----------------------------------------------------------------------===//
8428	// LValue Evaluation
8429	//
8430	// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
8431	// function designators (in C), decl references to void objects (in C), and
8432	// temporaries (if building with -Wno-address-of-temporary).
8433	//
8434	// LValue evaluation produces values comprising a base expression of one of the
8435	// following types:
8436	// - Declarations
8437	// * VarDecl
8438	// * FunctionDecl
8439	// - Literals
8440	// * CompoundLiteralExpr in C (and in global scope in C++)
8441	// * StringLiteral
8442	// * PredefinedExpr
8443	// * ObjCStringLiteralExpr
8444	// * ObjCEncodeExpr
8445	// * AddrLabelExpr
8446	// * BlockExpr
8447	// * CallExpr for a MakeStringConstant builtin
8448	// - typeid(T) expressions, as TypeInfoLValues
8449	// - Locals and temporaries
8450	// * MaterializeTemporaryExpr
8451	// * Any Expr, with a CallIndex indicating the function in which the temporary
8452	// was evaluated, for cases where the MaterializeTemporaryExpr is missing
8453	// from the AST (FIXME).
8454	// * A MaterializeTemporaryExpr that has static storage duration, with no
8455	// CallIndex, for a lifetime-extended temporary.
8456	// * The ConstantExpr that is currently being evaluated during evaluation of an
8457	// immediate invocation.
8458	// plus an offset in bytes.
8459	//===----------------------------------------------------------------------===//
8460	namespace {
8461	class LValueExprEvaluator
8462	: public LValueExprEvaluatorBase<LValueExprEvaluator> {
8463	public:
8464	LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
8465	LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
8466
8467	bool VisitVarDecl(const Expr *E, const VarDecl *VD);
8468	bool VisitUnaryPreIncDec(const UnaryOperator *UO);
8469
8470	bool VisitCallExpr(const CallExpr *E);
8471	bool VisitDeclRefExpr(const DeclRefExpr *E);
8472	bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
8473	bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
8474	bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
8475	bool VisitMemberExpr(const MemberExpr *E);
8476	bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
8477	bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
8478	bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
8479	bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
8480	bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
8481	bool VisitUnaryDeref(const UnaryOperator *E);
8482	bool VisitUnaryReal(const UnaryOperator *E);
8483	bool VisitUnaryImag(const UnaryOperator *E);
8484	bool VisitUnaryPreInc(const UnaryOperator *UO) {
8485	return VisitUnaryPreIncDec(UO);
8486	}
8487	bool VisitUnaryPreDec(const UnaryOperator *UO) {
8488	return VisitUnaryPreIncDec(UO);
8489	}
8490	bool VisitBinAssign(const BinaryOperator *BO);
8491	bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
8492
8493	bool VisitCastExpr(const CastExpr *E) {
8494	switch (E->getCastKind()) {
8495	default:
8496	return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
8497
8498	case CK_LValueBitCast:
8499	this->CCEDiag(E, diag::note_constexpr_invalid_cast)
8500	<< 2 << Info.Ctx.getLangOpts().CPlusPlus;
8501	if (!Visit(E->getSubExpr()))
8502	return false;
8503	Result.Designator.setInvalid();
8504	return true;
8505
8506	case CK_BaseToDerived:
8507	if (!Visit(E->getSubExpr()))
8508	return false;
8509	return HandleBaseToDerivedCast(Info, E, Result);
8510
8511	case CK_Dynamic:
8512	if (!Visit(E->getSubExpr()))
8513	return false;
8514	return HandleDynamicCast(Info, E: cast<ExplicitCastExpr>(Val: E), Ptr&: Result);
8515	}
8516	}
8517	};
8518	} // end anonymous namespace
8519
8520	/// Get an lvalue to a field of a lambda's closure type.
8521	static bool HandleLambdaCapture(EvalInfo &Info, const Expr *E, LValue &Result,
8522	const CXXMethodDecl *MD, const FieldDecl *FD,
8523	bool LValueToRValueConversion) {
8524	// Static lambda function call operators can't have captures. We already
8525	// diagnosed this, so bail out here.
8526	if (MD->isStatic()) {
8527	assert(Info.CurrentCall->This == nullptr &&
8528	"This should not be set for a static call operator");
8529	return false;
8530	}
8531
8532	// Start with 'Result' referring to the complete closure object...
8533	if (MD->isExplicitObjectMemberFunction()) {
8534	// Self may be passed by reference or by value.
8535	const ParmVarDecl *Self = MD->getParamDecl(0);
8536	if (Self->getType()->isReferenceType()) {
8537	APValue *RefValue = Info.getParamSlot(Call: Info.CurrentCall->Arguments, PVD: Self);
8538	Result.setFrom(Ctx&: Info.Ctx, V: *RefValue);
8539	} else {
8540	const ParmVarDecl *VD = Info.CurrentCall->Arguments.getOrigParam(PVD: Self);
8541	CallStackFrame *Frame =
8542	Info.getCallFrameAndDepth(CallIndex: Info.CurrentCall->Arguments.CallIndex)
8543	.first;
8544	unsigned Version = Info.CurrentCall->Arguments.Version;
8545	Result.set({VD, Frame->Index, Version});
8546	}
8547	} else
8548	Result = *Info.CurrentCall->This;
8549
8550	// ... then update it to refer to the field of the closure object
8551	// that represents the capture.
8552	if (!HandleLValueMember(Info, E, LVal&: Result, FD))
8553	return false;
8554
8555	// And if the field is of reference type (or if we captured '*this' by
8556	// reference), update 'Result' to refer to what
8557	// the field refers to.
8558	if (LValueToRValueConversion) {
8559	APValue RVal;
8560	if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result, RVal))
8561	return false;
8562	Result.setFrom(Ctx&: Info.Ctx, V: RVal);
8563	}
8564	return true;
8565	}
8566
8567	/// Evaluate an expression as an lvalue. This can be legitimately called on
8568	/// expressions which are not glvalues, in three cases:
8569	/// * function designators in C, and
8570	/// * "extern void" objects
8571	/// * @selector() expressions in Objective-C
8572	static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
8573	bool InvalidBaseOK) {
8574	assert(!E->isValueDependent());
8575	assert(E->isGLValue() || E->getType()->isFunctionType() ||
8576	E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E->IgnoreParens()));
8577	return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8578	}
8579
8580	bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
8581	const NamedDecl *D = E->getDecl();
8582	if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl,
8583	UnnamedGlobalConstantDecl>(Val: D))
8584	return Success(B: cast<ValueDecl>(Val: D));
8585	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
8586	return VisitVarDecl(E, VD);
8587	if (const BindingDecl *BD = dyn_cast<BindingDecl>(Val: D))
8588	return Visit(BD->getBinding());
8589	return Error(E);
8590	}
8591
8592
8593	bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
8594
8595	// If we are within a lambda's call operator, check whether the 'VD' referred
8596	// to within 'E' actually represents a lambda-capture that maps to a
8597	// data-member/field within the closure object, and if so, evaluate to the
8598	// field or what the field refers to.
8599	if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) &&
8600	isa<DeclRefExpr>(Val: E) &&
8601	cast<DeclRefExpr>(Val: E)->refersToEnclosingVariableOrCapture()) {
8602	// We don't always have a complete capture-map when checking or inferring if
8603	// the function call operator meets the requirements of a constexpr function
8604	// - but we don't need to evaluate the captures to determine constexprness
8605	// (dcl.constexpr C++17).
8606	if (Info.checkingPotentialConstantExpression())
8607	return false;
8608
8609	if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
8610	const auto *MD = cast<CXXMethodDecl>(Val: Info.CurrentCall->Callee);
8611	return HandleLambdaCapture(Info, E, Result, MD, FD,
8612	FD->getType()->isReferenceType());
8613	}
8614	}
8615
8616	CallStackFrame *Frame = nullptr;
8617	unsigned Version = 0;
8618	if (VD->hasLocalStorage()) {
8619	// Only if a local variable was declared in the function currently being
8620	// evaluated, do we expect to be able to find its value in the current
8621	// frame. (Otherwise it was likely declared in an enclosing context and
8622	// could either have a valid evaluatable value (for e.g. a constexpr
8623	// variable) or be ill-formed (and trigger an appropriate evaluation
8624	// diagnostic)).
8625	CallStackFrame *CurrFrame = Info.CurrentCall;
8626	if (CurrFrame->Callee && CurrFrame->Callee->Equals(DC: VD->getDeclContext())) {
8627	// Function parameters are stored in some caller's frame. (Usually the
8628	// immediate caller, but for an inherited constructor they may be more
8629	// distant.)
8630	if (auto *PVD = dyn_cast<ParmVarDecl>(Val: VD)) {
8631	if (CurrFrame->Arguments) {
8632	VD = CurrFrame->Arguments.getOrigParam(PVD);
8633	Frame =
8634	Info.getCallFrameAndDepth(CallIndex: CurrFrame->Arguments.CallIndex).first;
8635	Version = CurrFrame->Arguments.Version;
8636	}
8637	} else {
8638	Frame = CurrFrame;
8639	Version = CurrFrame->getCurrentTemporaryVersion(Key: VD);
8640	}
8641	}
8642	}
8643
8644	if (!VD->getType()->isReferenceType()) {
8645	if (Frame) {
8646	Result.set({VD, Frame->Index, Version});
8647	return true;
8648	}
8649	return Success(VD);
8650	}
8651
8652	if (!Info.getLangOpts().CPlusPlus11) {
8653	Info.CCEDiag(E, diag::note_constexpr_ltor_non_integral, 1)
8654	<< VD << VD->getType();
8655	Info.Note(VD->getLocation(), diag::note_declared_at);
8656	}
8657
8658	APValue *V;
8659	if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, Result&: V))
8660	return false;
8661	if (!V->hasValue()) {
8662	// FIXME: Is it possible for V to be indeterminate here? If so, we should
8663	// adjust the diagnostic to say that.
8664	if (!Info.checkingPotentialConstantExpression())
8665	Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
8666	return false;
8667	}
8668	return Success(V: *V, E);
8669	}
8670
8671	bool LValueExprEvaluator::VisitCallExpr(const CallExpr *E) {
8672	if (!IsConstantEvaluatedBuiltinCall(E))
8673	return ExprEvaluatorBaseTy::VisitCallExpr(E);
8674
8675	switch (E->getBuiltinCallee()) {
8676	default:
8677	return false;
8678	case Builtin::BIas_const:
8679	case Builtin::BIforward:
8680	case Builtin::BIforward_like:
8681	case Builtin::BImove:
8682	case Builtin::BImove_if_noexcept:
8683	if (cast<FunctionDecl>(Val: E->getCalleeDecl())->isConstexpr())
8684	return Visit(E->getArg(Arg: 0));
8685	break;
8686	}
8687
8688	return ExprEvaluatorBaseTy::VisitCallExpr(E);
8689	}
8690
8691	bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
8692	const MaterializeTemporaryExpr *E) {
8693	// Walk through the expression to find the materialized temporary itself.
8694	SmallVector<const Expr *, 2> CommaLHSs;
8695	SmallVector<SubobjectAdjustment, 2> Adjustments;
8696	const Expr *Inner =
8697	E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHS&: CommaLHSs, Adjustments);
8698
8699	// If we passed any comma operators, evaluate their LHSs.
8700	for (const Expr *E : CommaLHSs)
8701	if (!EvaluateIgnoredValue(Info, E))
8702	return false;
8703
8704	// A materialized temporary with static storage duration can appear within the
8705	// result of a constant expression evaluation, so we need to preserve its
8706	// value for use outside this evaluation.
8707	APValue *Value;
8708	if (E->getStorageDuration() == SD_Static) {
8709	if (Info.EvalMode == EvalInfo::EM_ConstantFold)
8710	return false;
8711	// FIXME: What about SD_Thread?
8712	Value = E->getOrCreateValue(MayCreate: true);
8713	*Value = APValue();
8714	Result.set(E);
8715	} else {
8716	Value = &Info.CurrentCall->createTemporary(
8717	Key: E, T: Inner->getType(),
8718	Scope: E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression
8719	: ScopeKind::Block,
8720	LV&: Result);
8721	}
8722
8723	QualType Type = Inner->getType();
8724
8725	// Materialize the temporary itself.
8726	if (!EvaluateInPlace(Result&: *Value, Info, This: Result, E: Inner)) {
8727	*Value = APValue();
8728	return false;
8729	}
8730
8731	// Adjust our lvalue to refer to the desired subobject.
8732	for (unsigned I = Adjustments.size(); I != 0; /**/) {
8733	--I;
8734	switch (Adjustments[I].Kind) {
8735	case SubobjectAdjustment::DerivedToBaseAdjustment:
8736	if (!HandleLValueBasePath(Info, E: Adjustments[I].DerivedToBase.BasePath,
8737	Type, Result))
8738	return false;
8739	Type = Adjustments[I].DerivedToBase.BasePath->getType();
8740	break;
8741
8742	case SubobjectAdjustment::FieldAdjustment:
8743	if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
8744	return false;
8745	Type = Adjustments[I].Field->getType();
8746	break;
8747
8748	case SubobjectAdjustment::MemberPointerAdjustment:
8749	if (!HandleMemberPointerAccess(Info&: this->Info, LVType: Type, LV&: Result,
8750	RHS: Adjustments[I].Ptr.RHS))
8751	return false;
8752	Type = Adjustments[I].Ptr.MPT->getPointeeType();
8753	break;
8754	}
8755	}
8756
8757	return true;
8758	}
8759
8760	bool
8761	LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
8762	assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
8763	"lvalue compound literal in c++?");
8764	// Defer visiting the literal until the lvalue-to-rvalue conversion. We can
8765	// only see this when folding in C, so there's no standard to follow here.
8766	return Success(E);
8767	}
8768
8769	bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
8770	TypeInfoLValue TypeInfo;
8771
8772	if (!E->isPotentiallyEvaluated()) {
8773	if (E->isTypeOperand())
8774	TypeInfo = TypeInfoLValue(E->getTypeOperand(Context&: Info.Ctx).getTypePtr());
8775	else
8776	TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
8777	} else {
8778	if (!Info.Ctx.getLangOpts().CPlusPlus20) {
8779	Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
8780	<< E->getExprOperand()->getType()
8781	<< E->getExprOperand()->getSourceRange();
8782	}
8783
8784	if (!Visit(E->getExprOperand()))
8785	return false;
8786
8787	std::optional<DynamicType> DynType =
8788	ComputeDynamicType(Info, E, Result, AK_TypeId);
8789	if (!DynType)
8790	return false;
8791
8792	TypeInfo =
8793	TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr());
8794	}
8795
8796	return Success(APValue::LValueBase::getTypeInfo(LV: TypeInfo, TypeInfo: E->getType()));
8797	}
8798
8799	bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
8800	return Success(E->getGuidDecl());
8801	}
8802
8803	bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
8804	// Handle static data members.
8805	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: E->getMemberDecl())) {
8806	VisitIgnoredBaseExpression(E: E->getBase());
8807	return VisitVarDecl(E, VD);
8808	}
8809
8810	// Handle static member functions.
8811	if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: E->getMemberDecl())) {
8812	if (MD->isStatic()) {
8813	VisitIgnoredBaseExpression(E: E->getBase());
8814	return Success(MD);
8815	}
8816	}
8817
8818	// Handle non-static data members.
8819	return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
8820	}
8821
8822	bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
8823	// FIXME: Deal with vectors as array subscript bases.
8824	if (E->getBase()->getType()->isVectorType() ||
8825	E->getBase()->getType()->isSveVLSBuiltinType())
8826	return Error(E);
8827
8828	APSInt Index;
8829	bool Success = true;
8830
8831	// C++17's rules require us to evaluate the LHS first, regardless of which
8832	// side is the base.
8833	for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) {
8834	if (SubExpr == E->getBase() ? !evaluatePointer(E: SubExpr, Result)
8835	: !EvaluateInteger(E: SubExpr, Result&: Index, Info)) {
8836	if (!Info.noteFailure())
8837	return false;
8838	Success = false;
8839	}
8840	}
8841
8842	return Success &&
8843	HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
8844	}
8845
8846	bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
8847	return evaluatePointer(E: E->getSubExpr(), Result);
8848	}
8849
8850	bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8851	if (!Visit(E->getSubExpr()))
8852	return false;
8853	// __real is a no-op on scalar lvalues.
8854	if (E->getSubExpr()->getType()->isAnyComplexType())
8855	HandleLValueComplexElement(Info, E, Result, E->getType(), false);
8856	return true;
8857	}
8858
8859	bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8860	assert(E->getSubExpr()->getType()->isAnyComplexType() &&
8861	"lvalue __imag__ on scalar?");
8862	if (!Visit(E->getSubExpr()))
8863	return false;
8864	HandleLValueComplexElement(Info, E, Result, E->getType(), true);
8865	return true;
8866	}
8867
8868	bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
8869	if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8870	return Error(UO);
8871
8872	if (!this->Visit(UO->getSubExpr()))
8873	return false;
8874
8875	return handleIncDec(
8876	this->Info, UO, Result, UO->getSubExpr()->getType(),
8877	UO->isIncrementOp(), nullptr);
8878	}
8879
8880	bool LValueExprEvaluator::VisitCompoundAssignOperator(
8881	const CompoundAssignOperator *CAO) {
8882	if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8883	return Error(CAO);
8884
8885	bool Success = true;
8886
8887	// C++17 onwards require that we evaluate the RHS first.
8888	APValue RHS;
8889	if (!Evaluate(RHS, this->Info, CAO->getRHS())) {
8890	if (!Info.noteFailure())
8891	return false;
8892	Success = false;
8893	}
8894
8895	// The overall lvalue result is the result of evaluating the LHS.
8896	if (!this->Visit(CAO->getLHS()) || !Success)
8897	return false;
8898
8899	return handleCompoundAssignment(
8900	this->Info, CAO,
8901	Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
8902	CAO->getOpForCompoundAssignment(Opc: CAO->getOpcode()), RHS);
8903	}
8904
8905	bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
8906	if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8907	return Error(E);
8908
8909	bool Success = true;
8910
8911	// C++17 onwards require that we evaluate the RHS first.
8912	APValue NewVal;
8913	if (!Evaluate(Result&: NewVal, Info&: this->Info, E: E->getRHS())) {
8914	if (!Info.noteFailure())
8915	return false;
8916	Success = false;
8917	}
8918
8919	if (!this->Visit(E->getLHS()) || !Success)
8920	return false;
8921
8922	if (Info.getLangOpts().CPlusPlus20 &&
8923	!MaybeHandleUnionActiveMemberChange(Info, LHSExpr: E->getLHS(), LHS: Result))
8924	return false;
8925
8926	return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
8927	NewVal);
8928	}
8929
8930	//===----------------------------------------------------------------------===//
8931	// Pointer Evaluation
8932	//===----------------------------------------------------------------------===//
8933
8934	/// Attempts to compute the number of bytes available at the pointer
8935	/// returned by a function with the alloc_size attribute. Returns true if we
8936	/// were successful. Places an unsigned number into `Result`.
8937	///
8938	/// This expects the given CallExpr to be a call to a function with an
8939	/// alloc_size attribute.
8940	static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8941	const CallExpr *Call,
8942	llvm::APInt &Result) {
8943	const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
8944
8945	assert(AllocSize && AllocSize->getElemSizeParam().isValid());
8946	unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
8947	unsigned BitsInSizeT = Ctx.getTypeSize(T: Ctx.getSizeType());
8948	if (Call->getNumArgs() <= SizeArgNo)
8949	return false;
8950
8951	auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
8952	Expr::EvalResult ExprResult;
8953	if (!E->EvaluateAsInt(Result&: ExprResult, Ctx, AllowSideEffects: Expr::SE_AllowSideEffects))
8954	return false;
8955	Into = ExprResult.Val.getInt();
8956	if (Into.isNegative() || !Into.isIntN(N: BitsInSizeT))
8957	return false;
8958	Into = Into.zext(width: BitsInSizeT);
8959	return true;
8960	};
8961
8962	APSInt SizeOfElem;
8963	if (!EvaluateAsSizeT(Call->getArg(Arg: SizeArgNo), SizeOfElem))
8964	return false;
8965
8966	if (!AllocSize->getNumElemsParam().isValid()) {
8967	Result = std::move(SizeOfElem);
8968	return true;
8969	}
8970
8971	APSInt NumberOfElems;
8972	unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
8973	if (!EvaluateAsSizeT(Call->getArg(Arg: NumArgNo), NumberOfElems))
8974	return false;
8975
8976	bool Overflow;
8977	llvm::APInt BytesAvailable = SizeOfElem.umul_ov(RHS: NumberOfElems, Overflow);
8978	if (Overflow)
8979	return false;
8980
8981	Result = std::move(BytesAvailable);
8982	return true;
8983	}
8984
8985	/// Convenience function. LVal's base must be a call to an alloc_size
8986	/// function.
8987	static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8988	const LValue &LVal,
8989	llvm::APInt &Result) {
8990	assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
8991	"Can't get the size of a non alloc_size function");
8992	const auto *Base = LVal.getLValueBase().get<const Expr *>();
8993	const CallExpr *CE = tryUnwrapAllocSizeCall(E: Base);
8994	return getBytesReturnedByAllocSizeCall(Ctx, Call: CE, Result);
8995	}
8996
8997	/// Attempts to evaluate the given LValueBase as the result of a call to
8998	/// a function with the alloc_size attribute. If it was possible to do so, this
8999	/// function will return true, make Result's Base point to said function call,
9000	/// and mark Result's Base as invalid.
9001	static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
9002	LValue &Result) {
9003	if (Base.isNull())
9004	return false;
9005
9006	// Because we do no form of static analysis, we only support const variables.
9007	//
9008	// Additionally, we can't support parameters, nor can we support static
9009	// variables (in the latter case, use-before-assign isn't UB; in the former,
9010	// we have no clue what they'll be assigned to).
9011	const auto *VD =
9012	dyn_cast_or_null<VarDecl>(Val: Base.dyn_cast<const ValueDecl *>());
9013	if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
9014	return false;
9015
9016	const Expr *Init = VD->getAnyInitializer();
9017	if (!Init || Init->getType().isNull())
9018	return false;
9019
9020	const Expr *E = Init->IgnoreParens();
9021	if (!tryUnwrapAllocSizeCall(E))
9022	return false;
9023
9024	// Store E instead of E unwrapped so that the type of the LValue's base is
9025	// what the user wanted.
9026	Result.setInvalid(B: E);
9027
9028	QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
9029	Result.addUnsizedArray(Info, E, ElemTy: Pointee);
9030	return true;
9031	}
9032
9033	namespace {
9034	class PointerExprEvaluator
9035	: public ExprEvaluatorBase<PointerExprEvaluator> {
9036	LValue &Result;
9037	bool InvalidBaseOK;
9038
9039	bool Success(const Expr *E) {
9040	Result.set(B: E);
9041	return true;
9042	}
9043
9044	bool evaluateLValue(const Expr *E, LValue &Result) {
9045	return EvaluateLValue(E, Result, Info, InvalidBaseOK);
9046	}
9047
9048	bool evaluatePointer(const Expr *E, LValue &Result) {
9049	return EvaluatePointer(E, Result, Info, InvalidBaseOK);
9050	}
9051
9052	bool visitNonBuiltinCallExpr(const CallExpr *E);
9053	public:
9054
9055	PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
9056	: ExprEvaluatorBaseTy(info), Result(Result),
9057	InvalidBaseOK(InvalidBaseOK) {}
9058
9059	bool Success(const APValue &V, const Expr *E) {
9060	Result.setFrom(Ctx&: Info.Ctx, V);
9061	return true;
9062	}
9063	bool ZeroInitialization(const Expr *E) {
9064	Result.setNull(Ctx&: Info.Ctx, PointerTy: E->getType());
9065	return true;
9066	}
9067
9068	bool VisitBinaryOperator(const BinaryOperator *E);
9069	bool VisitCastExpr(const CastExpr* E);
9070	bool VisitUnaryAddrOf(const UnaryOperator *E);
9071	bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
9072	{ return Success(E); }
9073	bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
9074	if (E->isExpressibleAsConstantInitializer())
9075	return Success(E);
9076	if (Info.noteFailure())
9077	EvaluateIgnoredValue(Info, E: E->getSubExpr());
9078	return Error(E);
9079	}
9080	bool VisitAddrLabelExpr(const AddrLabelExpr *E)
9081	{ return Success(E); }
9082	bool VisitCallExpr(const CallExpr *E);
9083	bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
9084	bool VisitBlockExpr(const BlockExpr *E) {
9085	if (!E->getBlockDecl()->hasCaptures())
9086	return Success(E);
9087	return Error(E);
9088	}
9089	bool VisitCXXThisExpr(const CXXThisExpr *E) {
9090	auto DiagnoseInvalidUseOfThis = [&] {
9091	if (Info.getLangOpts().CPlusPlus11)
9092	Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
9093	else
9094	Info.FFDiag(E);
9095	};
9096
9097	// Can't look at 'this' when checking a potential constant expression.
9098	if (Info.checkingPotentialConstantExpression())
9099	return false;
9100
9101	bool IsExplicitLambda =
9102	isLambdaCallWithExplicitObjectParameter(Info.CurrentCall->Callee);
9103	if (!IsExplicitLambda) {
9104	if (!Info.CurrentCall->This) {
9105	DiagnoseInvalidUseOfThis();
9106	return false;
9107	}
9108
9109	Result = *Info.CurrentCall->This;
9110	}
9111
9112	if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
9113	// Ensure we actually have captured 'this'. If something was wrong with
9114	// 'this' capture, the error would have been previously reported.
9115	// Otherwise we can be inside of a default initialization of an object
9116	// declared by lambda's body, so no need to return false.
9117	if (!Info.CurrentCall->LambdaThisCaptureField) {
9118	if (IsExplicitLambda && !Info.CurrentCall->This) {
9119	DiagnoseInvalidUseOfThis();
9120	return false;
9121	}
9122
9123	return true;
9124	}
9125
9126	const auto *MD = cast<CXXMethodDecl>(Val: Info.CurrentCall->Callee);
9127	return HandleLambdaCapture(
9128	Info, E, Result, MD, Info.CurrentCall->LambdaThisCaptureField,
9129	Info.CurrentCall->LambdaThisCaptureField->getType()->isPointerType());
9130	}
9131	return true;
9132	}
9133
9134	bool VisitCXXNewExpr(const CXXNewExpr *E);
9135
9136	bool VisitSourceLocExpr(const SourceLocExpr *E) {
9137	assert(!E->isIntType() && "SourceLocExpr isn't a pointer type?");
9138	APValue LValResult = E->EvaluateInContext(
9139	Ctx: Info.Ctx, DefaultExpr: Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
9140	Result.setFrom(Ctx&: Info.Ctx, V: LValResult);
9141	return true;
9142	}
9143
9144	bool VisitSYCLUniqueStableNameExpr(const SYCLUniqueStableNameExpr *E) {
9145	std::string ResultStr = E->ComputeName(Context&: Info.Ctx);
9146
9147	QualType CharTy = Info.Ctx.CharTy.withConst();
9148	APInt Size(Info.Ctx.getTypeSize(T: Info.Ctx.getSizeType()),
9149	ResultStr.size() + 1);
9150	QualType ArrayTy = Info.Ctx.getConstantArrayType(
9151	EltTy: CharTy, ArySize: Size, SizeExpr: nullptr, ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
9152
9153	StringLiteral *SL =
9154	StringLiteral::Create(Ctx: Info.Ctx, Str: ResultStr, Kind: StringLiteralKind::Ordinary,
9155	/*Pascal*/ false, Ty: ArrayTy, Loc: E->getLocation());
9156
9157	evaluateLValue(SL, Result);
9158	Result.addArray(Info, E, cast<ConstantArrayType>(Val&: ArrayTy));
9159	return true;
9160	}
9161
9162	// FIXME: Missing: @protocol, @selector
9163	};
9164	} // end anonymous namespace
9165
9166	static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
9167	bool InvalidBaseOK) {
9168	assert(!E->isValueDependent());
9169	assert(E->isPRValue() && E->getType()->hasPointerRepresentation());
9170	return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
9171	}
9172
9173	bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
9174	if (E->getOpcode() != BO_Add &&
9175	E->getOpcode() != BO_Sub)
9176	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
9177
9178	const Expr *PExp = E->getLHS();
9179	const Expr *IExp = E->getRHS();
9180	if (IExp->getType()->isPointerType())
9181	std::swap(a&: PExp, b&: IExp);
9182
9183	bool EvalPtrOK = evaluatePointer(E: PExp, Result);
9184	if (!EvalPtrOK && !Info.noteFailure())
9185	return false;
9186
9187	llvm::APSInt Offset;
9188	if (!EvaluateInteger(E: IExp, Result&: Offset, Info) || !EvalPtrOK)
9189	return false;
9190
9191	if (E->getOpcode() == BO_Sub)
9192	negateAsSigned(Int&: Offset);
9193
9194	QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
9195	return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
9196	}
9197
9198	bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
9199	return evaluateLValue(E: E->getSubExpr(), Result);
9200	}
9201
9202	// Is the provided decl 'std::source_location::current'?
9203	static bool IsDeclSourceLocationCurrent(const FunctionDecl *FD) {
9204	if (!FD)
9205	return false;
9206	const IdentifierInfo *FnII = FD->getIdentifier();
9207	if (!FnII || !FnII->isStr(Str: "current"))
9208	return false;
9209
9210	const auto *RD = dyn_cast<RecordDecl>(FD->getParent());
9211	if (!RD)
9212	return false;
9213
9214	const IdentifierInfo *ClassII = RD->getIdentifier();
9215	return RD->isInStdNamespace() && ClassII && ClassII->isStr(Str: "source_location");
9216	}
9217
9218	bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
9219	const Expr *SubExpr = E->getSubExpr();
9220
9221	switch (E->getCastKind()) {
9222	default:
9223	break;
9224	case CK_BitCast:
9225	case CK_CPointerToObjCPointerCast:
9226	case CK_BlockPointerToObjCPointerCast:
9227	case CK_AnyPointerToBlockPointerCast:
9228	case CK_AddressSpaceConversion:
9229	if (!Visit(SubExpr))
9230	return false;
9231	// Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
9232	// permitted in constant expressions in C++11. Bitcasts from cv void* are
9233	// also static_casts, but we disallow them as a resolution to DR1312.
9234	if (!E->getType()->isVoidPointerType()) {
9235	// In some circumstances, we permit casting from void* to cv1 T*, when the
9236	// actual pointee object is actually a cv2 T.
9237	bool HasValidResult = !Result.InvalidBase && !Result.Designator.Invalid &&
9238	!Result.IsNullPtr;
9239	bool VoidPtrCastMaybeOK =
9240	HasValidResult &&
9241	Info.Ctx.hasSameUnqualifiedType(T1: Result.Designator.getType(Info.Ctx),
9242	T2: E->getType()->getPointeeType());
9243	// 1. We'll allow it in std::allocator::allocate, and anything which that
9244	// calls.
9245	// 2. HACK 2022-03-28: Work around an issue with libstdc++'s
9246	// <source_location> header. Fixed in GCC 12 and later (2022-04-??).
9247	// We'll allow it in the body of std::source_location::current. GCC's
9248	// implementation had a parameter of type `void*`, and casts from
9249	// that back to `const __impl*` in its body.
9250	if (VoidPtrCastMaybeOK &&
9251	(Info.getStdAllocatorCaller(FnName: "allocate") ||
9252	IsDeclSourceLocationCurrent(FD: Info.CurrentCall->Callee) ||
9253	Info.getLangOpts().CPlusPlus26)) {
9254	// Permitted.
9255	} else {
9256	if (SubExpr->getType()->isVoidPointerType() &&
9257	Info.getLangOpts().CPlusPlus) {
9258	if (HasValidResult)
9259	CCEDiag(E, diag::note_constexpr_invalid_void_star_cast)
9260	<< SubExpr->getType() << Info.getLangOpts().CPlusPlus26
9261	<< Result.Designator.getType(Info.Ctx).getCanonicalType()
9262	<< E->getType()->getPointeeType();
9263	else
9264	CCEDiag(E, diag::note_constexpr_invalid_cast)
9265	<< 3 << SubExpr->getType();
9266	} else
9267	CCEDiag(E, diag::note_constexpr_invalid_cast)
9268	<< 2 << Info.Ctx.getLangOpts().CPlusPlus;
9269	Result.Designator.setInvalid();
9270	}
9271	}
9272	if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
9273	ZeroInitialization(E);
9274	return true;
9275
9276	case CK_DerivedToBase:
9277	case CK_UncheckedDerivedToBase:
9278	if (!evaluatePointer(E: E->getSubExpr(), Result))
9279	return false;
9280	if (!Result.Base && Result.Offset.isZero())
9281	return true;
9282
9283	// Now figure out the necessary offset to add to the base LV to get from
9284	// the derived class to the base class.
9285	return HandleLValueBasePath(Info, E, Type: E->getSubExpr()->getType()->
9286	castAs<PointerType>()->getPointeeType(),
9287	Result);
9288
9289	case CK_BaseToDerived:
9290	if (!Visit(E->getSubExpr()))
9291	return false;
9292	if (!Result.Base && Result.Offset.isZero())
9293	return true;
9294	return HandleBaseToDerivedCast(Info, E, Result);
9295
9296	case CK_Dynamic:
9297	if (!Visit(E->getSubExpr()))
9298	return false;
9299	return HandleDynamicCast(Info, E: cast<ExplicitCastExpr>(Val: E), Ptr&: Result);
9300
9301	case CK_NullToPointer:
9302	VisitIgnoredValue(E: E->getSubExpr());
9303	return ZeroInitialization(E);
9304
9305	case CK_IntegralToPointer: {
9306	CCEDiag(E, diag::note_constexpr_invalid_cast)
9307	<< 2 << Info.Ctx.getLangOpts().CPlusPlus;
9308
9309	APValue Value;
9310	if (!EvaluateIntegerOrLValue(E: SubExpr, Result&: Value, Info))
9311	break;
9312
9313	if (Value.isInt()) {
9314	unsigned Size = Info.Ctx.getTypeSize(E->getType());
9315	uint64_t N = Value.getInt().extOrTrunc(width: Size).getZExtValue();
9316	Result.Base = (Expr*)nullptr;
9317	Result.InvalidBase = false;
9318	Result.Offset = CharUnits::fromQuantity(Quantity: N);
9319	Result.Designator.setInvalid();
9320	Result.IsNullPtr = false;
9321	return true;
9322	} else {
9323	// Cast is of an lvalue, no need to change value.
9324	Result.setFrom(Ctx&: Info.Ctx, V: Value);
9325	return true;
9326	}
9327	}
9328
9329	case CK_ArrayToPointerDecay: {
9330	if (SubExpr->isGLValue()) {
9331	if (!evaluateLValue(E: SubExpr, Result))
9332	return false;
9333	} else {
9334	APValue &Value = Info.CurrentCall->createTemporary(
9335	Key: SubExpr, T: SubExpr->getType(), Scope: ScopeKind::FullExpression, LV&: Result);
9336	if (!EvaluateInPlace(Result&: Value, Info, This: Result, E: SubExpr))
9337	return false;
9338	}
9339	// The result is a pointer to the first element of the array.
9340	auto *AT = Info.Ctx.getAsArrayType(T: SubExpr->getType());
9341	if (auto *CAT = dyn_cast<ConstantArrayType>(Val: AT))
9342	Result.addArray(Info, E, CAT);
9343	else
9344	Result.addUnsizedArray(Info, E, AT->getElementType());
9345	return true;
9346	}
9347
9348	case CK_FunctionToPointerDecay:
9349	return evaluateLValue(E: SubExpr, Result);
9350
9351	case CK_LValueToRValue: {
9352	LValue LVal;
9353	if (!evaluateLValue(E: E->getSubExpr(), Result&: LVal))
9354	return false;
9355
9356	APValue RVal;
9357	// Note, we use the subexpression's type in order to retain cv-qualifiers.
9358	if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
9359	LVal, RVal))
9360	return InvalidBaseOK &&
9361	evaluateLValueAsAllocSize(Info, Base: LVal.Base, Result);
9362	return Success(RVal, E);
9363	}
9364	}
9365
9366	return ExprEvaluatorBaseTy::VisitCastExpr(E);
9367	}
9368
9369	static CharUnits GetAlignOfType(EvalInfo &Info, QualType T,
9370	UnaryExprOrTypeTrait ExprKind) {
9371	// C++ [expr.alignof]p3:
9372	// When alignof is applied to a reference type, the result is the
9373	// alignment of the referenced type.
9374	T = T.getNonReferenceType();
9375
9376	if (T.getQualifiers().hasUnaligned())
9377	return CharUnits::One();
9378
9379	const bool AlignOfReturnsPreferred =
9380	Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;
9381
9382	// __alignof is defined to return the preferred alignment.
9383	// Before 8, clang returned the preferred alignment for alignof and _Alignof
9384	// as well.
9385	if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
9386	return Info.Ctx.toCharUnitsFromBits(
9387	BitSize: Info.Ctx.getPreferredTypeAlign(T: T.getTypePtr()));
9388	// alignof and _Alignof are defined to return the ABI alignment.
9389	else if (ExprKind == UETT_AlignOf)
9390	return Info.Ctx.getTypeAlignInChars(T: T.getTypePtr());
9391	else
9392	llvm_unreachable("GetAlignOfType on a non-alignment ExprKind");
9393	}
9394
9395	static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E,
9396	UnaryExprOrTypeTrait ExprKind) {
9397	E = E->IgnoreParens();
9398
9399	// The kinds of expressions that we have special-case logic here for
9400	// should be kept up to date with the special checks for those
9401	// expressions in Sema.
9402
9403	// alignof decl is always accepted, even if it doesn't make sense: we default
9404	// to 1 in those cases.
9405	if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: E))
9406	return Info.Ctx.getDeclAlign(DRE->getDecl(),
9407	/*RefAsPointee*/true);
9408
9409	if (const MemberExpr *ME = dyn_cast<MemberExpr>(Val: E))
9410	return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
9411	/*RefAsPointee*/true);
9412
9413	return GetAlignOfType(Info, T: E->getType(), ExprKind);
9414	}
9415
9416	static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
9417	if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
9418	return Info.Ctx.getDeclAlign(VD);
9419	if (const auto *E = Value.Base.dyn_cast<const Expr *>())
9420	return GetAlignOfExpr(Info, E, ExprKind: UETT_AlignOf);
9421	return GetAlignOfType(Info, T: Value.Base.getTypeInfoType(), ExprKind: UETT_AlignOf);
9422	}
9423
9424	/// Evaluate the value of the alignment argument to __builtin_align_{up,down},
9425	/// __builtin_is_aligned and __builtin_assume_aligned.
9426	static bool getAlignmentArgument(const Expr *E, QualType ForType,
9427	EvalInfo &Info, APSInt &Alignment) {
9428	if (!EvaluateInteger(E, Result&: Alignment, Info))
9429	return false;
9430	if (Alignment < 0 || !Alignment.isPowerOf2()) {
9431	Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment;
9432	return false;
9433	}
9434	unsigned SrcWidth = Info.Ctx.getIntWidth(T: ForType);
9435	APSInt MaxValue(APInt::getOneBitSet(numBits: SrcWidth, BitNo: SrcWidth - 1));
9436	if (APSInt::compareValues(I1: Alignment, I2: MaxValue) > 0) {
9437	Info.FFDiag(E, diag::note_constexpr_alignment_too_big)
9438	<< MaxValue << ForType << Alignment;
9439	return false;
9440	}
9441	// Ensure both alignment and source value have the same bit width so that we
9442	// don't assert when computing the resulting value.
9443	APSInt ExtAlignment =
9444	APSInt(Alignment.zextOrTrunc(width: SrcWidth), /*isUnsigned=*/true);
9445	assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&
9446	"Alignment should not be changed by ext/trunc");
9447	Alignment = ExtAlignment;
9448	assert(Alignment.getBitWidth() == SrcWidth);
9449	return true;
9450	}
9451
9452	// To be clear: this happily visits unsupported builtins. Better name welcomed.
9453	bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
9454	if (ExprEvaluatorBaseTy::VisitCallExpr(E))
9455	return true;
9456
9457	if (!(InvalidBaseOK && getAllocSizeAttr(E)))
9458	return false;
9459
9460	Result.setInvalid(E);
9461	QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
9462	Result.addUnsizedArray(Info, E, PointeeTy);
9463	return true;
9464	}
9465
9466	bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
9467	if (!IsConstantEvaluatedBuiltinCall(E))
9468	return visitNonBuiltinCallExpr(E);
9469	return VisitBuiltinCallExpr(E, BuiltinOp: E->getBuiltinCallee());
9470	}
9471
9472	// Determine if T is a character type for which we guarantee that
9473	// sizeof(T) == 1.
9474	static bool isOneByteCharacterType(QualType T) {
9475	return T->isCharType() || T->isChar8Type();
9476	}
9477
9478	bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
9479	unsigned BuiltinOp) {
9480	if (IsNoOpCall(E))
9481	return Success(E);
9482
9483	switch (BuiltinOp) {
9484	case Builtin::BIaddressof:
9485	case Builtin::BI__addressof:
9486	case Builtin::BI__builtin_addressof:
9487	return evaluateLValue(E: E->getArg(Arg: 0), Result);
9488	case Builtin::BI__builtin_assume_aligned: {
9489	// We need to be very careful here because: if the pointer does not have the
9490	// asserted alignment, then the behavior is undefined, and undefined
9491	// behavior is non-constant.
9492	if (!evaluatePointer(E: E->getArg(Arg: 0), Result))
9493	return false;
9494
9495	LValue OffsetResult(Result);
9496	APSInt Alignment;
9497	if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: E->getArg(Arg: 0)->getType(), Info,
9498	Alignment))
9499	return false;
9500	CharUnits Align = CharUnits::fromQuantity(Quantity: Alignment.getZExtValue());
9501
9502	if (E->getNumArgs() > 2) {
9503	APSInt Offset;
9504	if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: Offset, Info))
9505	return false;
9506
9507	int64_t AdditionalOffset = -Offset.getZExtValue();
9508	OffsetResult.Offset += CharUnits::fromQuantity(Quantity: AdditionalOffset);
9509	}
9510
9511	// If there is a base object, then it must have the correct alignment.
9512	if (OffsetResult.Base) {
9513	CharUnits BaseAlignment = getBaseAlignment(Info, Value: OffsetResult);
9514
9515	if (BaseAlignment < Align) {
9516	Result.Designator.setInvalid();
9517	// FIXME: Add support to Diagnostic for long / long long.
9518	CCEDiag(E->getArg(0),
9519	diag::note_constexpr_baa_insufficient_alignment) << 0
9520	<< (unsigned)BaseAlignment.getQuantity()
9521	<< (unsigned)Align.getQuantity();
9522	return false;
9523	}
9524	}
9525
9526	// The offset must also have the correct alignment.
9527	if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
9528	Result.Designator.setInvalid();
9529
9530	(OffsetResult.Base
9531	? CCEDiag(E->getArg(0),
9532	diag::note_constexpr_baa_insufficient_alignment) << 1
9533	: CCEDiag(E->getArg(0),
9534	diag::note_constexpr_baa_value_insufficient_alignment))
9535	<< (int)OffsetResult.Offset.getQuantity()
9536	<< (unsigned)Align.getQuantity();
9537	return false;
9538	}
9539
9540	return true;
9541	}
9542	case Builtin::BI__builtin_align_up:
9543	case Builtin::BI__builtin_align_down: {
9544	if (!evaluatePointer(E: E->getArg(Arg: 0), Result))
9545	return false;
9546	APSInt Alignment;
9547	if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: E->getArg(Arg: 0)->getType(), Info,
9548	Alignment))
9549	return false;
9550	CharUnits BaseAlignment = getBaseAlignment(Info, Value: Result);
9551	CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(offset: Result.Offset);
9552	// For align_up/align_down, we can return the same value if the alignment
9553	// is known to be greater or equal to the requested value.
9554	if (PtrAlign.getQuantity() >= Alignment)
9555	return true;
9556
9557	// The alignment could be greater than the minimum at run-time, so we cannot
9558	// infer much about the resulting pointer value. One case is possible:
9559	// For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
9560	// can infer the correct index if the requested alignment is smaller than
9561	// the base alignment so we can perform the computation on the offset.
9562	if (BaseAlignment.getQuantity() >= Alignment) {
9563	assert(Alignment.getBitWidth() <= 64 &&
9564	"Cannot handle > 64-bit address-space");
9565	uint64_t Alignment64 = Alignment.getZExtValue();
9566	CharUnits NewOffset = CharUnits::fromQuantity(
9567	BuiltinOp == Builtin::BI__builtin_align_down
9568	? llvm::alignDown(Result.Offset.getQuantity(), Alignment64)
9569	: llvm::alignTo(Result.Offset.getQuantity(), Alignment64));
9570	Result.adjustOffset(N: NewOffset - Result.Offset);
9571	// TODO: diagnose out-of-bounds values/only allow for arrays?
9572	return true;
9573	}
9574	// Otherwise, we cannot constant-evaluate the result.
9575	Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust)
9576	<< Alignment;
9577	return false;
9578	}
9579	case Builtin::BI__builtin_operator_new:
9580	return HandleOperatorNewCall(Info, E, Result);
9581	case Builtin::BI__builtin_launder:
9582	return evaluatePointer(E: E->getArg(Arg: 0), Result);
9583	case Builtin::BIstrchr:
9584	case Builtin::BIwcschr:
9585	case Builtin::BImemchr:
9586	case Builtin::BIwmemchr:
9587	if (Info.getLangOpts().CPlusPlus11)
9588	Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9589	<< /*isConstexpr*/ 0 << /*isConstructor*/ 0
9590	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
9591	else
9592	Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9593	[[fallthrough]];
9594	case Builtin::BI__builtin_strchr:
9595	case Builtin::BI__builtin_wcschr:
9596	case Builtin::BI__builtin_memchr:
9597	case Builtin::BI__builtin_char_memchr:
9598	case Builtin::BI__builtin_wmemchr: {
9599	if (!Visit(E->getArg(Arg: 0)))
9600	return false;
9601	APSInt Desired;
9602	if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: Desired, Info))
9603	return false;
9604	uint64_t MaxLength = uint64_t(-1);
9605	if (BuiltinOp != Builtin::BIstrchr &&
9606	BuiltinOp != Builtin::BIwcschr &&
9607	BuiltinOp != Builtin::BI__builtin_strchr &&
9608	BuiltinOp != Builtin::BI__builtin_wcschr) {
9609	APSInt N;
9610	if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
9611	return false;
9612	MaxLength = N.getZExtValue();
9613	}
9614	// We cannot find the value if there are no candidates to match against.
9615	if (MaxLength == 0u)
9616	return ZeroInitialization(E);
9617	if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
9618	Result.Designator.Invalid)
9619	return false;
9620	QualType CharTy = Result.Designator.getType(Info.Ctx);
9621	bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
9622	BuiltinOp == Builtin::BI__builtin_memchr;
9623	assert(IsRawByte ||
9624	Info.Ctx.hasSameUnqualifiedType(
9625	CharTy, E->getArg(0)->getType()->getPointeeType()));
9626	// Pointers to const void may point to objects of incomplete type.
9627	if (IsRawByte && CharTy->isIncompleteType()) {
9628	Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy;
9629	return false;
9630	}
9631	// Give up on byte-oriented matching against multibyte elements.
9632	// FIXME: We can compare the bytes in the correct order.
9633	if (IsRawByte && !isOneByteCharacterType(T: CharTy)) {
9634	Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
9635	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str()
9636	<< CharTy;
9637	return false;
9638	}
9639	// Figure out what value we're actually looking for (after converting to
9640	// the corresponding unsigned type if necessary).
9641	uint64_t DesiredVal;
9642	bool StopAtNull = false;
9643	switch (BuiltinOp) {
9644	case Builtin::BIstrchr:
9645	case Builtin::BI__builtin_strchr:
9646	// strchr compares directly to the passed integer, and therefore
9647	// always fails if given an int that is not a char.
9648	if (!APSInt::isSameValue(I1: HandleIntToIntCast(Info, E, CharTy,
9649	E->getArg(Arg: 1)->getType(),
9650	Desired),
9651	I2: Desired))
9652	return ZeroInitialization(E);
9653	StopAtNull = true;
9654	[[fallthrough]];
9655	case Builtin::BImemchr:
9656	case Builtin::BI__builtin_memchr:
9657	case Builtin::BI__builtin_char_memchr:
9658	// memchr compares by converting both sides to unsigned char. That's also
9659	// correct for strchr if we get this far (to cope with plain char being
9660	// unsigned in the strchr case).
9661	DesiredVal = Desired.trunc(width: Info.Ctx.getCharWidth()).getZExtValue();
9662	break;
9663
9664	case Builtin::BIwcschr:
9665	case Builtin::BI__builtin_wcschr:
9666	StopAtNull = true;
9667	[[fallthrough]];
9668	case Builtin::BIwmemchr:
9669	case Builtin::BI__builtin_wmemchr:
9670	// wcschr and wmemchr are given a wchar_t to look for. Just use it.
9671	DesiredVal = Desired.getZExtValue();
9672	break;
9673	}
9674
9675	for (; MaxLength; --MaxLength) {
9676	APValue Char;
9677	if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
9678	!Char.isInt())
9679	return false;
9680	if (Char.getInt().getZExtValue() == DesiredVal)
9681	return true;
9682	if (StopAtNull && !Char.getInt())
9683	break;
9684	if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
9685	return false;
9686	}
9687	// Not found: return nullptr.
9688	return ZeroInitialization(E);
9689	}
9690
9691	case Builtin::BImemcpy:
9692	case Builtin::BImemmove:
9693	case Builtin::BIwmemcpy:
9694	case Builtin::BIwmemmove:
9695	if (Info.getLangOpts().CPlusPlus11)
9696	Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9697	<< /*isConstexpr*/ 0 << /*isConstructor*/ 0
9698	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
9699	else
9700	Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9701	[[fallthrough]];
9702	case Builtin::BI__builtin_memcpy:
9703	case Builtin::BI__builtin_memmove:
9704	case Builtin::BI__builtin_wmemcpy:
9705	case Builtin::BI__builtin_wmemmove: {
9706	bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
9707	BuiltinOp == Builtin::BIwmemmove ||
9708	BuiltinOp == Builtin::BI__builtin_wmemcpy ||
9709	BuiltinOp == Builtin::BI__builtin_wmemmove;
9710	bool Move = BuiltinOp == Builtin::BImemmove ||
9711	BuiltinOp == Builtin::BIwmemmove ||
9712	BuiltinOp == Builtin::BI__builtin_memmove ||
9713	BuiltinOp == Builtin::BI__builtin_wmemmove;
9714
9715	// The result of mem* is the first argument.
9716	if (!Visit(E->getArg(Arg: 0)))
9717	return false;
9718	LValue Dest = Result;
9719
9720	LValue Src;
9721	if (!EvaluatePointer(E: E->getArg(Arg: 1), Result&: Src, Info))
9722	return false;
9723
9724	APSInt N;
9725	if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
9726	return false;
9727	assert(!N.isSigned() && "memcpy and friends take an unsigned size");
9728
9729	// If the size is zero, we treat this as always being a valid no-op.
9730	// (Even if one of the src and dest pointers is null.)
9731	if (!N)
9732	return true;
9733
9734	// Otherwise, if either of the operands is null, we can't proceed. Don't
9735	// try to determine the type of the copied objects, because there aren't
9736	// any.
9737	if (!Src.Base || !Dest.Base) {
9738	APValue Val;
9739	(!Src.Base ? Src : Dest).moveInto(V&: Val);
9740	Info.FFDiag(E, diag::note_constexpr_memcpy_null)
9741	<< Move << WChar << !!Src.Base
9742	<< Val.getAsString(Info.Ctx, E->getArg(0)->getType());
9743	return false;
9744	}
9745	if (Src.Designator.Invalid || Dest.Designator.Invalid)
9746	return false;
9747
9748	// We require that Src and Dest are both pointers to arrays of
9749	// trivially-copyable type. (For the wide version, the designator will be
9750	// invalid if the designated object is not a wchar_t.)
9751	QualType T = Dest.Designator.getType(Info.Ctx);
9752	QualType SrcT = Src.Designator.getType(Info.Ctx);
9753	if (!Info.Ctx.hasSameUnqualifiedType(T1: T, T2: SrcT)) {
9754	// FIXME: Consider using our bit_cast implementation to support this.
9755	Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
9756	return false;
9757	}
9758	if (T->isIncompleteType()) {
9759	Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T;
9760	return false;
9761	}
9762	if (!T.isTriviallyCopyableType(Context: Info.Ctx)) {
9763	Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T;
9764	return false;
9765	}
9766
9767	// Figure out how many T's we're copying.
9768	uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
9769	if (TSize == 0)
9770	return false;
9771	if (!WChar) {
9772	uint64_t Remainder;
9773	llvm::APInt OrigN = N;
9774	llvm::APInt::udivrem(LHS: OrigN, RHS: TSize, Quotient&: N, Remainder);
9775	if (Remainder) {
9776	Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9777	<< Move << WChar << 0 << T << toString(OrigN, 10, /*Signed*/false)
9778	<< (unsigned)TSize;
9779	return false;
9780	}
9781	}
9782
9783	// Check that the copying will remain within the arrays, just so that we
9784	// can give a more meaningful diagnostic. This implicitly also checks that
9785	// N fits into 64 bits.
9786	uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
9787	uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
9788	if (N.ugt(RHS: RemainingSrcSize) || N.ugt(RHS: RemainingDestSize)) {
9789	Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9790	<< Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T
9791	<< toString(N, 10, /*Signed*/false);
9792	return false;
9793	}
9794	uint64_t NElems = N.getZExtValue();
9795	uint64_t NBytes = NElems * TSize;
9796
9797	// Check for overlap.
9798	int Direction = 1;
9799	if (HasSameBase(A: Src, B: Dest)) {
9800	uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
9801	uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
9802	if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
9803	// Dest is inside the source region.
9804	if (!Move) {
9805	Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9806	return false;
9807	}
9808	// For memmove and friends, copy backwards.
9809	if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) ||
9810	!HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1))
9811	return false;
9812	Direction = -1;
9813	} else if (!Move && SrcOffset >= DestOffset &&
9814	SrcOffset - DestOffset < NBytes) {
9815	// Src is inside the destination region for memcpy: invalid.
9816	Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9817	return false;
9818	}
9819	}
9820
9821	while (true) {
9822	APValue Val;
9823	// FIXME: Set WantObjectRepresentation to true if we're copying a
9824	// char-like type?
9825	if (!handleLValueToRValueConversion(Info, E, T, Src, Val) ||
9826	!handleAssignment(Info, E, Dest, T, Val))
9827	return false;
9828	// Do not iterate past the last element; if we're copying backwards, that
9829	// might take us off the start of the array.
9830	if (--NElems == 0)
9831	return true;
9832	if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) ||
9833	!HandleLValueArrayAdjustment(Info, E, Dest, T, Direction))
9834	return false;
9835	}
9836	}
9837
9838	default:
9839	return false;
9840	}
9841	}
9842
9843	static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
9844	APValue &Result, const InitListExpr *ILE,
9845	QualType AllocType);
9846	static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
9847	APValue &Result,
9848	const CXXConstructExpr *CCE,
9849	QualType AllocType);
9850
9851	bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
9852	if (!Info.getLangOpts().CPlusPlus20)
9853	Info.CCEDiag(E, diag::note_constexpr_new);
9854
9855	// We cannot speculatively evaluate a delete expression.
9856	if (Info.SpeculativeEvaluationDepth)
9857	return false;
9858
9859	FunctionDecl *OperatorNew = E->getOperatorNew();
9860
9861	bool IsNothrow = false;
9862	bool IsPlacement = false;
9863	if (OperatorNew->isReservedGlobalPlacementOperator() &&
9864	Info.CurrentCall->isStdFunction() && !E->isArray()) {
9865	// FIXME Support array placement new.
9866	assert(E->getNumPlacementArgs() == 1);
9867	if (!EvaluatePointer(E: E->getPlacementArg(I: 0), Result, Info))
9868	return false;
9869	if (Result.Designator.Invalid)
9870	return false;
9871	IsPlacement = true;
9872	} else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) {
9873	Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
9874	<< isa<CXXMethodDecl>(OperatorNew) << OperatorNew;
9875	return false;
9876	} else if (E->getNumPlacementArgs()) {
9877	// The only new-placement list we support is of the form (std::nothrow).
9878	//
9879	// FIXME: There is no restriction on this, but it's not clear that any
9880	// other form makes any sense. We get here for cases such as:
9881	//
9882	// new (std::align_val_t{N}) X(int)
9883	//
9884	// (which should presumably be valid only if N is a multiple of
9885	// alignof(int), and in any case can't be deallocated unless N is
9886	// alignof(X) and X has new-extended alignment).
9887	if (E->getNumPlacementArgs() != 1 ||
9888	!E->getPlacementArg(0)->getType()->isNothrowT())
9889	return Error(E, diag::note_constexpr_new_placement);
9890
9891	LValue Nothrow;
9892	if (!EvaluateLValue(E: E->getPlacementArg(I: 0), Result&: Nothrow, Info))
9893	return false;
9894	IsNothrow = true;
9895	}
9896
9897	const Expr *Init = E->getInitializer();
9898	const InitListExpr *ResizedArrayILE = nullptr;
9899	const CXXConstructExpr *ResizedArrayCCE = nullptr;
9900	bool ValueInit = false;
9901
9902	QualType AllocType = E->getAllocatedType();
9903	if (std::optional<const Expr *> ArraySize = E->getArraySize()) {
9904	const Expr *Stripped = *ArraySize;
9905	for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Val: Stripped);
9906	Stripped = ICE->getSubExpr())
9907	if (ICE->getCastKind() != CK_NoOp &&
9908	ICE->getCastKind() != CK_IntegralCast)
9909	break;
9910
9911	llvm::APSInt ArrayBound;
9912	if (!EvaluateInteger(E: Stripped, Result&: ArrayBound, Info))
9913	return false;
9914
9915	// C++ [expr.new]p9:
9916	// The expression is erroneous if:
9917	// -- [...] its value before converting to size_t [or] applying the
9918	// second standard conversion sequence is less than zero
9919	if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
9920	if (IsNothrow)
9921	return ZeroInitialization(E);
9922
9923	Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative)
9924	<< ArrayBound << (*ArraySize)->getSourceRange();
9925	return false;
9926	}
9927
9928	// -- its value is such that the size of the allocated object would
9929	// exceed the implementation-defined limit
9930	if (!Info.CheckArraySize(Loc: ArraySize.value()->getExprLoc(),
9931	BitWidth: ConstantArrayType::getNumAddressingBits(
9932	Context: Info.Ctx, ElementType: AllocType, NumElements: ArrayBound),
9933	ElemCount: ArrayBound.getZExtValue(), /*Diag=*/!IsNothrow)) {
9934	if (IsNothrow)
9935	return ZeroInitialization(E);
9936	return false;
9937	}
9938
9939	// -- the new-initializer is a braced-init-list and the number of
9940	// array elements for which initializers are provided [...]
9941	// exceeds the number of elements to initialize
9942	if (!Init) {
9943	// No initialization is performed.
9944	} else if (isa<CXXScalarValueInitExpr>(Val: Init) ||
9945	isa<ImplicitValueInitExpr>(Val: Init)) {
9946	ValueInit = true;
9947	} else if (auto *CCE = dyn_cast<CXXConstructExpr>(Val: Init)) {
9948	ResizedArrayCCE = CCE;
9949	} else {
9950	auto *CAT = Info.Ctx.getAsConstantArrayType(T: Init->getType());
9951	assert(CAT && "unexpected type for array initializer");
9952
9953	unsigned Bits =
9954	std::max(a: CAT->getSizeBitWidth(), b: ArrayBound.getBitWidth());
9955	llvm::APInt InitBound = CAT->getSize().zext(width: Bits);
9956	llvm::APInt AllocBound = ArrayBound.zext(width: Bits);
9957	if (InitBound.ugt(RHS: AllocBound)) {
9958	if (IsNothrow)
9959	return ZeroInitialization(E);
9960
9961	Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small)
9962	<< toString(AllocBound, 10, /*Signed=*/false)
9963	<< toString(InitBound, 10, /*Signed=*/false)
9964	<< (*ArraySize)->getSourceRange();
9965	return false;
9966	}
9967
9968	// If the sizes differ, we must have an initializer list, and we need
9969	// special handling for this case when we initialize.
9970	if (InitBound != AllocBound)
9971	ResizedArrayILE = cast<InitListExpr>(Val: Init);
9972	}
9973
9974	AllocType = Info.Ctx.getConstantArrayType(EltTy: AllocType, ArySize: ArrayBound, SizeExpr: nullptr,
9975	ASM: ArraySizeModifier::Normal, IndexTypeQuals: 0);
9976	} else {
9977	assert(!AllocType->isArrayType() &&
9978	"array allocation with non-array new");
9979	}
9980
9981	APValue *Val;
9982	if (IsPlacement) {
9983	AccessKinds AK = AK_Construct;
9984	struct FindObjectHandler {
9985	EvalInfo &Info;
9986	const Expr *E;
9987	QualType AllocType;
9988	const AccessKinds AccessKind;
9989	APValue *Value;
9990
9991	typedef bool result_type;
9992	bool failed() { return false; }
9993	bool found(APValue &Subobj, QualType SubobjType) {
9994	// FIXME: Reject the cases where [basic.life]p8 would not permit the
9995	// old name of the object to be used to name the new object.
9996	if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) {
9997	Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) <<
9998	SubobjType << AllocType;
9999	return false;
10000	}
10001	Value = &Subobj;
10002	return true;
10003	}
10004	bool found(APSInt &Value, QualType SubobjType) {
10005	Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
10006	return false;
10007	}
10008	bool found(APFloat &Value, QualType SubobjType) {
10009	Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
10010	return false;
10011	}
10012	} Handler = {Info, E, AllocType, AK, nullptr};
10013
10014	CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType);
10015	if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler))
10016	return false;
10017
10018	Val = Handler.Value;
10019
10020	// [basic.life]p1:
10021	// The lifetime of an object o of type T ends when [...] the storage
10022	// which the object occupies is [...] reused by an object that is not
10023	// nested within o (6.6.2).
10024	*Val = APValue();
10025	} else {
10026	// Perform the allocation and obtain a pointer to the resulting object.
10027	Val = Info.createHeapAlloc(E, AllocType, Result);
10028	if (!Val)
10029	return false;
10030	}
10031
10032	if (ValueInit) {
10033	ImplicitValueInitExpr VIE(AllocType);
10034	if (!EvaluateInPlace(*Val, Info, Result, &VIE))
10035	return false;
10036	} else if (ResizedArrayILE) {
10037	if (!EvaluateArrayNewInitList(Info, This&: Result, Result&: *Val, ILE: ResizedArrayILE,
10038	AllocType))
10039	return false;
10040	} else if (ResizedArrayCCE) {
10041	if (!EvaluateArrayNewConstructExpr(Info, This&: Result, Result&: *Val, CCE: ResizedArrayCCE,
10042	AllocType))
10043	return false;
10044	} else if (Init) {
10045	if (!EvaluateInPlace(Result&: *Val, Info, This: Result, E: Init))
10046	return false;
10047	} else if (!handleDefaultInitValue(T: AllocType, Result&: *Val)) {
10048	return false;
10049	}
10050
10051	// Array new returns a pointer to the first element, not a pointer to the
10052	// array.
10053	if (auto *AT = AllocType->getAsArrayTypeUnsafe())
10054	Result.addArray(Info, E, CAT: cast<ConstantArrayType>(AT));
10055
10056	return true;
10057	}
10058	//===----------------------------------------------------------------------===//
10059	// Member Pointer Evaluation
10060	//===----------------------------------------------------------------------===//
10061
10062	namespace {
10063	class MemberPointerExprEvaluator
10064	: public ExprEvaluatorBase<MemberPointerExprEvaluator> {
10065	MemberPtr &Result;
10066
10067	bool Success(const ValueDecl *D) {
10068	Result = MemberPtr(D);
10069	return true;
10070	}
10071	public:
10072
10073	MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
10074	: ExprEvaluatorBaseTy(Info), Result(Result) {}
10075
10076	bool Success(const APValue &V, const Expr *E) {
10077	Result.setFrom(V);
10078	return true;
10079	}
10080	bool ZeroInitialization(const Expr *E) {
10081	return Success(D: (const ValueDecl*)nullptr);
10082	}
10083
10084	bool VisitCastExpr(const CastExpr *E);
10085	bool VisitUnaryAddrOf(const UnaryOperator *E);
10086	};
10087	} // end anonymous namespace
10088
10089	static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
10090	EvalInfo &Info) {
10091	assert(!E->isValueDependent());
10092	assert(E->isPRValue() && E->getType()->isMemberPointerType());
10093	return MemberPointerExprEvaluator(Info, Result).Visit(E);
10094	}
10095
10096	bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
10097	switch (E->getCastKind()) {
10098	default:
10099	return ExprEvaluatorBaseTy::VisitCastExpr(E);
10100
10101	case CK_NullToMemberPointer:
10102	VisitIgnoredValue(E: E->getSubExpr());
10103	return ZeroInitialization(E);
10104
10105	case CK_BaseToDerivedMemberPointer: {
10106	if (!Visit(E->getSubExpr()))
10107	return false;
10108	if (E->path_empty())
10109	return true;
10110	// Base-to-derived member pointer casts store the path in derived-to-base
10111	// order, so iterate backwards. The CXXBaseSpecifier also provides us with
10112	// the wrong end of the derived->base arc, so stagger the path by one class.
10113	typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
10114	for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
10115	PathI != PathE; ++PathI) {
10116	assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
10117	const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
10118	if (!Result.castToDerived(Derived))
10119	return Error(E);
10120	}
10121	const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
10122	if (!Result.castToDerived(Derived: FinalTy->getAsCXXRecordDecl()))
10123	return Error(E);
10124	return true;
10125	}
10126
10127	case CK_DerivedToBaseMemberPointer:
10128	if (!Visit(E->getSubExpr()))
10129	return false;
10130	for (CastExpr::path_const_iterator PathI = E->path_begin(),
10131	PathE = E->path_end(); PathI != PathE; ++PathI) {
10132	assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
10133	const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
10134	if (!Result.castToBase(Base))
10135	return Error(E);
10136	}
10137	return true;
10138	}
10139	}
10140
10141	bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
10142	// C++11 [expr.unary.op]p3 has very strict rules on how the address of a
10143	// member can be formed.
10144	return Success(D: cast<DeclRefExpr>(Val: E->getSubExpr())->getDecl());
10145	}
10146
10147	//===----------------------------------------------------------------------===//
10148	// Record Evaluation
10149	//===----------------------------------------------------------------------===//
10150
10151	namespace {
10152	class RecordExprEvaluator
10153	: public ExprEvaluatorBase<RecordExprEvaluator> {
10154	const LValue &This;
10155	APValue &Result;
10156	public:
10157
10158	RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
10159	: ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
10160
10161	bool Success(const APValue &V, const Expr *E) {
10162	Result = V;
10163	return true;
10164	}
10165	bool ZeroInitialization(const Expr *E) {
10166	return ZeroInitialization(E, T: E->getType());
10167	}
10168	bool ZeroInitialization(const Expr *E, QualType T);
10169
10170	bool VisitCallExpr(const CallExpr *E) {
10171	return handleCallExpr(E, Result, ResultSlot: &This);
10172	}
10173	bool VisitCastExpr(const CastExpr *E);
10174	bool VisitInitListExpr(const InitListExpr *E);
10175	bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
10176	return VisitCXXConstructExpr(E, E->getType());
10177	}
10178	bool VisitLambdaExpr(const LambdaExpr *E);
10179	bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
10180	bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
10181	bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
10182	bool VisitBinCmp(const BinaryOperator *E);
10183	bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E);
10184	bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit,
10185	ArrayRef<Expr *> Args);
10186	};
10187	}
10188
10189	/// Perform zero-initialization on an object of non-union class type.
10190	/// C++11 [dcl.init]p5:
10191	/// To zero-initialize an object or reference of type T means:
10192	/// [...]
10193	/// -- if T is a (possibly cv-qualified) non-union class type,
10194	/// each non-static data member and each base-class subobject is
10195	/// zero-initialized
10196	static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
10197	const RecordDecl *RD,
10198	const LValue &This, APValue &Result) {
10199	assert(!RD->isUnion() && "Expected non-union class type");
10200	const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(Val: RD);
10201	Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
10202	std::distance(first: RD->field_begin(), last: RD->field_end()));
10203
10204	if (RD->isInvalidDecl()) return false;
10205	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
10206
10207	if (CD) {
10208	unsigned Index = 0;
10209	for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
10210	End = CD->bases_end(); I != End; ++I, ++Index) {
10211	const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
10212	LValue Subobject = This;
10213	if (!HandleLValueDirectBase(Info, E, Obj&: Subobject, Derived: CD, Base, RL: &Layout))
10214	return false;
10215	if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
10216	Result.getStructBase(i: Index)))
10217	return false;
10218	}
10219	}
10220
10221	for (const auto *I : RD->fields()) {
10222	// -- if T is a reference type, no initialization is performed.
10223	if (I->isUnnamedBitField() || I->getType()->isReferenceType())
10224	continue;
10225
10226	LValue Subobject = This;
10227	if (!HandleLValueMember(Info, E, LVal&: Subobject, FD: I, RL: &Layout))
10228	return false;
10229
10230	ImplicitValueInitExpr VIE(I->getType());
10231	if (!EvaluateInPlace(
10232	Result.getStructField(i: I->getFieldIndex()), Info, Subobject, &VIE))
10233	return false;
10234	}
10235
10236	return true;
10237	}
10238
10239	bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
10240	const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
10241	if (RD->isInvalidDecl()) return false;
10242	if (RD->isUnion()) {
10243	// C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
10244	// object's first non-static named data member is zero-initialized
10245	RecordDecl::field_iterator I = RD->field_begin();
10246	while (I != RD->field_end() && (*I)->isUnnamedBitField())
10247	++I;
10248	if (I == RD->field_end()) {
10249	Result = APValue((const FieldDecl*)nullptr);
10250	return true;
10251	}
10252
10253	LValue Subobject = This;
10254	if (!HandleLValueMember(Info, E, LVal&: Subobject, FD: *I))
10255	return false;
10256	Result = APValue(*I);
10257	ImplicitValueInitExpr VIE(I->getType());
10258	return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
10259	}
10260
10261	if (isa<CXXRecordDecl>(Val: RD) && cast<CXXRecordDecl>(Val: RD)->getNumVBases()) {
10262	Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
10263	return false;
10264	}
10265
10266	return HandleClassZeroInitialization(Info, E, RD, This, Result);
10267	}
10268
10269	bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
10270	switch (E->getCastKind()) {
10271	default:
10272	return ExprEvaluatorBaseTy::VisitCastExpr(E);
10273
10274	case CK_ConstructorConversion:
10275	return Visit(E->getSubExpr());
10276
10277	case CK_DerivedToBase:
10278	case CK_UncheckedDerivedToBase: {
10279	APValue DerivedObject;
10280	if (!Evaluate(Result&: DerivedObject, Info, E: E->getSubExpr()))
10281	return false;
10282	if (!DerivedObject.isStruct())
10283	return Error(E: E->getSubExpr());
10284
10285	// Derived-to-base rvalue conversion: just slice off the derived part.
10286	APValue *Value = &DerivedObject;
10287	const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
10288	for (CastExpr::path_const_iterator PathI = E->path_begin(),
10289	PathE = E->path_end(); PathI != PathE; ++PathI) {
10290	assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
10291	const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
10292	Value = &Value->getStructBase(i: getBaseIndex(Derived: RD, Base));
10293	RD = Base;
10294	}
10295	Result = *Value;
10296	return true;
10297	}
10298	}
10299	}
10300
10301	bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
10302	if (E->isTransparent())
10303	return Visit(E->getInit(Init: 0));
10304	return VisitCXXParenListOrInitListExpr(E, E->inits());
10305	}
10306
10307	bool RecordExprEvaluator::VisitCXXParenListOrInitListExpr(
10308	const Expr *ExprToVisit, ArrayRef<Expr *> Args) {
10309	const RecordDecl *RD =
10310	ExprToVisit->getType()->castAs<RecordType>()->getDecl();
10311	if (RD->isInvalidDecl()) return false;
10312	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(D: RD);
10313	auto *CXXRD = dyn_cast<CXXRecordDecl>(Val: RD);
10314
10315	EvalInfo::EvaluatingConstructorRAII EvalObj(
10316	Info,
10317	ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
10318	CXXRD && CXXRD->getNumBases());
10319
10320	if (RD->isUnion()) {
10321	const FieldDecl *Field;
10322	if (auto *ILE = dyn_cast<InitListExpr>(Val: ExprToVisit)) {
10323	Field = ILE->getInitializedFieldInUnion();
10324	} else if (auto *PLIE = dyn_cast<CXXParenListInitExpr>(Val: ExprToVisit)) {
10325	Field = PLIE->getInitializedFieldInUnion();
10326	} else {
10327	llvm_unreachable(
10328	"Expression is neither an init list nor a C++ paren list");
10329	}
10330
10331	Result = APValue(Field);
10332	if (!Field)
10333	return true;
10334
10335	// If the initializer list for a union does not contain any elements, the
10336	// first element of the union is value-initialized.
10337	// FIXME: The element should be initialized from an initializer list.
10338	// Is this difference ever observable for initializer lists which
10339	// we don't build?
10340	ImplicitValueInitExpr VIE(Field->getType());
10341	const Expr *InitExpr = Args.empty() ? &VIE : Args[0];
10342
10343	LValue Subobject = This;
10344	if (!HandleLValueMember(Info, E: InitExpr, LVal&: Subobject, FD: Field, RL: &Layout))
10345	return false;
10346
10347	// Temporarily override This, in case there's a CXXDefaultInitExpr in here.
10348	ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
10349	isa<CXXDefaultInitExpr>(Val: InitExpr));
10350
10351	if (EvaluateInPlace(Result&: Result.getUnionValue(), Info, This: Subobject, E: InitExpr)) {
10352	if (Field->isBitField())
10353	return truncateBitfieldValue(Info, E: InitExpr, Value&: Result.getUnionValue(),
10354	FD: Field);
10355	return true;
10356	}
10357
10358	return false;
10359	}
10360
10361	if (!Result.hasValue())
10362	Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
10363	std::distance(first: RD->field_begin(), last: RD->field_end()));
10364	unsigned ElementNo = 0;
10365	bool Success = true;
10366
10367	// Initialize base classes.
10368	if (CXXRD && CXXRD->getNumBases()) {
10369	for (const auto &Base : CXXRD->bases()) {
10370	assert(ElementNo < Args.size() && "missing init for base class");
10371	const Expr *Init = Args[ElementNo];
10372
10373	LValue Subobject = This;
10374	if (!HandleLValueBase(Info, E: Init, Obj&: Subobject, DerivedDecl: CXXRD, Base: &Base))
10375	return false;
10376
10377	APValue &FieldVal = Result.getStructBase(i: ElementNo);
10378	if (!EvaluateInPlace(Result&: FieldVal, Info, This: Subobject, E: Init)) {
10379	if (!Info.noteFailure())
10380	return false;
10381	Success = false;
10382	}
10383	++ElementNo;
10384	}
10385
10386	EvalObj.finishedConstructingBases();
10387	}
10388
10389	// Initialize members.
10390	for (const auto *Field : RD->fields()) {
10391	// Anonymous bit-fields are not considered members of the class for
10392	// purposes of aggregate initialization.
10393	if (Field->isUnnamedBitField())
10394	continue;
10395
10396	LValue Subobject = This;
10397
10398	bool HaveInit = ElementNo < Args.size();
10399
10400	// FIXME: Diagnostics here should point to the end of the initializer
10401	// list, not the start.
10402	if (!HandleLValueMember(Info, E: HaveInit ? Args[ElementNo] : ExprToVisit,
10403	LVal&: Subobject, FD: Field, RL: &Layout))
10404	return false;
10405
10406	// Perform an implicit value-initialization for members beyond the end of
10407	// the initializer list.
10408	ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
10409	const Expr *Init = HaveInit ? Args[ElementNo++] : &VIE;
10410
10411	if (Field->getType()->isIncompleteArrayType()) {
10412	if (auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType())) {
10413	if (!CAT->isZeroSize()) {
10414	// Bail out for now. This might sort of "work", but the rest of the
10415	// code isn't really prepared to handle it.
10416	Info.FFDiag(Init, diag::note_constexpr_unsupported_flexible_array);
10417	return false;
10418	}
10419	}
10420	}
10421
10422	// Temporarily override This, in case there's a CXXDefaultInitExpr in here.
10423	ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
10424	isa<CXXDefaultInitExpr>(Val: Init));
10425
10426	APValue &FieldVal = Result.getStructField(i: Field->getFieldIndex());
10427	if (!EvaluateInPlace(Result&: FieldVal, Info, This: Subobject, E: Init) ||
10428	(Field->isBitField() && !truncateBitfieldValue(Info, E: Init,
10429	Value&: FieldVal, FD: Field))) {
10430	if (!Info.noteFailure())
10431	return false;
10432	Success = false;
10433	}
10434	}
10435
10436	EvalObj.finishedConstructingFields();
10437
10438	return Success;
10439	}
10440
10441	bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
10442	QualType T) {
10443	// Note that E's type is not necessarily the type of our class here; we might
10444	// be initializing an array element instead.
10445	const CXXConstructorDecl *FD = E->getConstructor();
10446	if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
10447
10448	bool ZeroInit = E->requiresZeroInitialization();
10449	if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
10450	// If we've already performed zero-initialization, we're already done.
10451	if (Result.hasValue())
10452	return true;
10453
10454	if (ZeroInit)
10455	return ZeroInitialization(E, T);
10456
10457	return handleDefaultInitValue(T, Result);
10458	}
10459
10460	const FunctionDecl *Definition = nullptr;
10461	auto Body = FD->getBody(Definition);
10462
10463	if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
10464	return false;
10465
10466	// Avoid materializing a temporary for an elidable copy/move constructor.
10467	if (E->isElidable() && !ZeroInit) {
10468	// FIXME: This only handles the simplest case, where the source object
10469	// is passed directly as the first argument to the constructor.
10470	// This should also handle stepping though implicit casts and
10471	// and conversion sequences which involve two steps, with a
10472	// conversion operator followed by a converting constructor.
10473	const Expr *SrcObj = E->getArg(Arg: 0);
10474	assert(SrcObj->isTemporaryObject(Info.Ctx, FD->getParent()));
10475	assert(Info.Ctx.hasSameUnqualifiedType(E->getType(), SrcObj->getType()));
10476	if (const MaterializeTemporaryExpr *ME =
10477	dyn_cast<MaterializeTemporaryExpr>(Val: SrcObj))
10478	return Visit(ME->getSubExpr());
10479	}
10480
10481	if (ZeroInit && !ZeroInitialization(E, T))
10482	return false;
10483
10484	auto Args = llvm::ArrayRef(E->getArgs(), E->getNumArgs());
10485	return HandleConstructorCall(E, This, Args,
10486	cast<CXXConstructorDecl>(Val: Definition), Info,
10487	Result);
10488	}
10489
10490	bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
10491	const CXXInheritedCtorInitExpr *E) {
10492	if (!Info.CurrentCall) {
10493	assert(Info.checkingPotentialConstantExpression());
10494	return false;
10495	}
10496
10497	const CXXConstructorDecl *FD = E->getConstructor();
10498	if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
10499	return false;
10500
10501	const FunctionDecl *Definition = nullptr;
10502	auto Body = FD->getBody(Definition);
10503
10504	if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
10505	return false;
10506
10507	return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
10508	cast<CXXConstructorDecl>(Val: Definition), Info,
10509	Result);
10510	}
10511
10512	bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
10513	const CXXStdInitializerListExpr *E) {
10514	const ConstantArrayType *ArrayType =
10515	Info.Ctx.getAsConstantArrayType(T: E->getSubExpr()->getType());
10516
10517	LValue Array;
10518	if (!EvaluateLValue(E: E->getSubExpr(), Result&: Array, Info))
10519	return false;
10520
10521	assert(ArrayType && "unexpected type for array initializer");
10522
10523	// Get a pointer to the first element of the array.
10524	Array.addArray(Info, E, ArrayType);
10525
10526	auto InvalidType = [&] {
10527	Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
10528	<< E->getType();
10529	return false;
10530	};
10531
10532	// FIXME: Perform the checks on the field types in SemaInit.
10533	RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
10534	RecordDecl::field_iterator Field = Record->field_begin();
10535	if (Field == Record->field_end())
10536	return InvalidType();
10537
10538	// Start pointer.
10539	if (!Field->getType()->isPointerType() ||
10540	!Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
10541	ArrayType->getElementType()))
10542	return InvalidType();
10543
10544	// FIXME: What if the initializer_list type has base classes, etc?
10545	Result = APValue(APValue::UninitStruct(), 0, 2);
10546	Array.moveInto(V&: Result.getStructField(i: 0));
10547
10548	if (++Field == Record->field_end())
10549	return InvalidType();
10550
10551	if (Field->getType()->isPointerType() &&
10552	Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
10553	ArrayType->getElementType())) {
10554	// End pointer.
10555	if (!HandleLValueArrayAdjustment(Info, E, Array,
10556	ArrayType->getElementType(),
10557	ArrayType->getZExtSize()))
10558	return false;
10559	Array.moveInto(V&: Result.getStructField(i: 1));
10560	} else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
10561	// Length.
10562	Result.getStructField(i: 1) = APValue(APSInt(ArrayType->getSize()));
10563	else
10564	return InvalidType();
10565
10566	if (++Field != Record->field_end())
10567	return InvalidType();
10568
10569	return true;
10570	}
10571
10572	bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
10573	const CXXRecordDecl *ClosureClass = E->getLambdaClass();
10574	if (ClosureClass->isInvalidDecl())
10575	return false;
10576
10577	const size_t NumFields =
10578	std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
10579
10580	assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
10581	E->capture_init_end()) &&
10582	"The number of lambda capture initializers should equal the number of "
10583	"fields within the closure type");
10584
10585	Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
10586	// Iterate through all the lambda's closure object's fields and initialize
10587	// them.
10588	auto *CaptureInitIt = E->capture_init_begin();
10589	bool Success = true;
10590	const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(ClosureClass);
10591	for (const auto *Field : ClosureClass->fields()) {
10592	assert(CaptureInitIt != E->capture_init_end());
10593	// Get the initializer for this field
10594	Expr *const CurFieldInit = *CaptureInitIt++;
10595
10596	// If there is no initializer, either this is a VLA or an error has
10597	// occurred.
10598	if (!CurFieldInit)
10599	return Error(E);
10600
10601	LValue Subobject = This;
10602
10603	if (!HandleLValueMember(Info, E, Subobject, Field, &Layout))
10604	return false;
10605
10606	APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
10607	if (!EvaluateInPlace(FieldVal, Info, Subobject, CurFieldInit)) {
10608	if (!Info.keepEvaluatingAfterFailure())
10609	return false;
10610	Success = false;
10611	}
10612	}
10613	return Success;
10614	}
10615
10616	static bool EvaluateRecord(const Expr *E, const LValue &This,
10617	APValue &Result, EvalInfo &Info) {
10618	assert(!E->isValueDependent());
10619	assert(E->isPRValue() && E->getType()->isRecordType() &&
10620	"can't evaluate expression as a record rvalue");
10621	return RecordExprEvaluator(Info, This, Result).Visit(E);
10622	}
10623
10624	//===----------------------------------------------------------------------===//
10625	// Temporary Evaluation
10626	//
10627	// Temporaries are represented in the AST as rvalues, but generally behave like
10628	// lvalues. The full-object of which the temporary is a subobject is implicitly
10629	// materialized so that a reference can bind to it.
10630	//===----------------------------------------------------------------------===//
10631	namespace {
10632	class TemporaryExprEvaluator
10633	: public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
10634	public:
10635	TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
10636	LValueExprEvaluatorBaseTy(Info, Result, false) {}
10637
10638	/// Visit an expression which constructs the value of this temporary.
10639	bool VisitConstructExpr(const Expr *E) {
10640	APValue &Value = Info.CurrentCall->createTemporary(
10641	Key: E, T: E->getType(), Scope: ScopeKind::FullExpression, LV&: Result);
10642	return EvaluateInPlace(Result&: Value, Info, This: Result, E);
10643	}
10644
10645	bool VisitCastExpr(const CastExpr *E) {
10646	switch (E->getCastKind()) {
10647	default:
10648	return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
10649
10650	case CK_ConstructorConversion:
10651	return VisitConstructExpr(E: E->getSubExpr());
10652	}
10653	}
10654	bool VisitInitListExpr(const InitListExpr *E) {
10655	return VisitConstructExpr(E);
10656	}
10657	bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
10658	return VisitConstructExpr(E);
10659	}
10660	bool VisitCallExpr(const CallExpr *E) {
10661	return VisitConstructExpr(E);
10662	}
10663	bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
10664	return VisitConstructExpr(E);
10665	}
10666	bool VisitLambdaExpr(const LambdaExpr *E) {
10667	return VisitConstructExpr(E);
10668	}
10669	};
10670	} // end anonymous namespace
10671
10672	/// Evaluate an expression of record type as a temporary.
10673	static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
10674	assert(!E->isValueDependent());
10675	assert(E->isPRValue() && E->getType()->isRecordType());
10676	return TemporaryExprEvaluator(Info, Result).Visit(E);
10677	}
10678
10679	//===----------------------------------------------------------------------===//
10680	// Vector Evaluation
10681	//===----------------------------------------------------------------------===//
10682
10683	namespace {
10684	class VectorExprEvaluator
10685	: public ExprEvaluatorBase<VectorExprEvaluator> {
10686	APValue &Result;
10687	public:
10688
10689	VectorExprEvaluator(EvalInfo &info, APValue &Result)
10690	: ExprEvaluatorBaseTy(info), Result(Result) {}
10691
10692	bool Success(ArrayRef<APValue> V, const Expr *E) {
10693	assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
10694	// FIXME: remove this APValue copy.
10695	Result = APValue(V.data(), V.size());
10696	return true;
10697	}
10698	bool Success(const APValue &V, const Expr *E) {
10699	assert(V.isVector());
10700	Result = V;
10701	return true;
10702	}
10703	bool ZeroInitialization(const Expr *E);
10704
10705	bool VisitUnaryReal(const UnaryOperator *E)
10706	{ return Visit(E->getSubExpr()); }
10707	bool VisitCastExpr(const CastExpr* E);
10708	bool VisitInitListExpr(const InitListExpr *E);
10709	bool VisitUnaryImag(const UnaryOperator *E);
10710	bool VisitBinaryOperator(const BinaryOperator *E);
10711	bool VisitUnaryOperator(const UnaryOperator *E);
10712	// FIXME: Missing: conditional operator (for GNU
10713	// conditional select), shufflevector, ExtVectorElementExpr
10714	};
10715	} // end anonymous namespace
10716
10717	static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
10718	assert(E->isPRValue() && E->getType()->isVectorType() &&
10719	"not a vector prvalue");
10720	return VectorExprEvaluator(Info, Result).Visit(E);
10721	}
10722
10723	bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
10724	const VectorType *VTy = E->getType()->castAs<VectorType>();
10725	unsigned NElts = VTy->getNumElements();
10726
10727	const Expr *SE = E->getSubExpr();
10728	QualType SETy = SE->getType();
10729
10730	switch (E->getCastKind()) {
10731	case CK_VectorSplat: {
10732	APValue Val = APValue();
10733	if (SETy->isIntegerType()) {
10734	APSInt IntResult;
10735	if (!EvaluateInteger(E: SE, Result&: IntResult, Info))
10736	return false;
10737	Val = APValue(std::move(IntResult));
10738	} else if (SETy->isRealFloatingType()) {
10739	APFloat FloatResult(0.0);
10740	if (!EvaluateFloat(E: SE, Result&: FloatResult, Info))
10741	return false;
10742	Val = APValue(std::move(FloatResult));
10743	} else {
10744	return Error(E);
10745	}
10746
10747	// Splat and create vector APValue.
10748	SmallVector<APValue, 4> Elts(NElts, Val);
10749	return Success(Elts, E);
10750	}
10751	case CK_BitCast: {
10752	APValue SVal;
10753	if (!Evaluate(Result&: SVal, Info, E: SE))
10754	return false;
10755
10756	if (!SVal.isInt() && !SVal.isFloat() && !SVal.isVector()) {
10757	// Give up if the input isn't an int, float, or vector. For example, we
10758	// reject "(v4i16)(intptr_t)&a".
10759	Info.FFDiag(E, diag::note_constexpr_invalid_cast)
10760	<< 2 << Info.Ctx.getLangOpts().CPlusPlus;
10761	return false;
10762	}
10763
10764	if (!handleRValueToRValueBitCast(Info, DestValue&: Result, SourceRValue: SVal, BCE: E))
10765	return false;
10766
10767	return true;
10768	}
10769	default:
10770	return ExprEvaluatorBaseTy::VisitCastExpr(E);
10771	}
10772	}
10773
10774	bool
10775	VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
10776	const VectorType *VT = E->getType()->castAs<VectorType>();
10777	unsigned NumInits = E->getNumInits();
10778	unsigned NumElements = VT->getNumElements();
10779
10780	QualType EltTy = VT->getElementType();
10781	SmallVector<APValue, 4> Elements;
10782
10783	// The number of initializers can be less than the number of
10784	// vector elements. For OpenCL, this can be due to nested vector
10785	// initialization. For GCC compatibility, missing trailing elements
10786	// should be initialized with zeroes.
10787	unsigned CountInits = 0, CountElts = 0;
10788	while (CountElts < NumElements) {
10789	// Handle nested vector initialization.
10790	if (CountInits < NumInits
10791	&& E->getInit(Init: CountInits)->getType()->isVectorType()) {
10792	APValue v;
10793	if (!EvaluateVector(E: E->getInit(Init: CountInits), Result&: v, Info))
10794	return Error(E);
10795	unsigned vlen = v.getVectorLength();
10796	for (unsigned j = 0; j < vlen; j++)
10797	Elements.push_back(Elt: v.getVectorElt(I: j));
10798	CountElts += vlen;
10799	} else if (EltTy->isIntegerType()) {
10800	llvm::APSInt sInt(32);
10801	if (CountInits < NumInits) {
10802	if (!EvaluateInteger(E: E->getInit(Init: CountInits), Result&: sInt, Info))
10803	return false;
10804	} else // trailing integer zero.
10805	sInt = Info.Ctx.MakeIntValue(Value: 0, Type: EltTy);
10806	Elements.push_back(Elt: APValue(sInt));
10807	CountElts++;
10808	} else {
10809	llvm::APFloat f(0.0);
10810	if (CountInits < NumInits) {
10811	if (!EvaluateFloat(E: E->getInit(Init: CountInits), Result&: f, Info))
10812	return false;
10813	} else // trailing float zero.
10814	f = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: EltTy));
10815	Elements.push_back(Elt: APValue(f));
10816	CountElts++;
10817	}
10818	CountInits++;
10819	}
10820	return Success(Elements, E);
10821	}
10822
10823	bool
10824	VectorExprEvaluator::ZeroInitialization(const Expr *E) {
10825	const auto *VT = E->getType()->castAs<VectorType>();
10826	QualType EltTy = VT->getElementType();
10827	APValue ZeroElement;
10828	if (EltTy->isIntegerType())
10829	ZeroElement = APValue(Info.Ctx.MakeIntValue(Value: 0, Type: EltTy));
10830	else
10831	ZeroElement =
10832	APValue(APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: EltTy)));
10833
10834	SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
10835	return Success(V: Elements, E);
10836	}
10837
10838	bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
10839	VisitIgnoredValue(E: E->getSubExpr());
10840	return ZeroInitialization(E);
10841	}
10842
10843	bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
10844	BinaryOperatorKind Op = E->getOpcode();
10845	assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&
10846	"Operation not supported on vector types");
10847
10848	if (Op == BO_Comma)
10849	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
10850
10851	Expr *LHS = E->getLHS();
10852	Expr *RHS = E->getRHS();
10853
10854	assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&
10855	"Must both be vector types");
10856	// Checking JUST the types are the same would be fine, except shifts don't
10857	// need to have their types be the same (since you always shift by an int).
10858	assert(LHS->getType()->castAs<VectorType>()->getNumElements() ==
10859	E->getType()->castAs<VectorType>()->getNumElements() &&
10860	RHS->getType()->castAs<VectorType>()->getNumElements() ==
10861	E->getType()->castAs<VectorType>()->getNumElements() &&
10862	"All operands must be the same size.");
10863
10864	APValue LHSValue;
10865	APValue RHSValue;
10866	bool LHSOK = Evaluate(Result&: LHSValue, Info, E: LHS);
10867	if (!LHSOK && !Info.noteFailure())
10868	return false;
10869	if (!Evaluate(Result&: RHSValue, Info, E: RHS) || !LHSOK)
10870	return false;
10871
10872	if (!handleVectorVectorBinOp(Info, E, Opcode: Op, LHSValue, RHSValue))
10873	return false;
10874
10875	return Success(LHSValue, E);
10876	}
10877
10878	static std::optional<APValue> handleVectorUnaryOperator(ASTContext &Ctx,
10879	QualType ResultTy,
10880	UnaryOperatorKind Op,
10881	APValue Elt) {
10882	switch (Op) {
10883	case UO_Plus:
10884	// Nothing to do here.
10885	return Elt;
10886	case UO_Minus:
10887	if (Elt.getKind() == APValue::Int) {
10888	Elt.getInt().negate();
10889	} else {
10890	assert(Elt.getKind() == APValue::Float &&
10891	"Vector can only be int or float type");
10892	Elt.getFloat().changeSign();
10893	}
10894	return Elt;
10895	case UO_Not:
10896	// This is only valid for integral types anyway, so we don't have to handle
10897	// float here.
10898	assert(Elt.getKind() == APValue::Int &&
10899	"Vector operator ~ can only be int");
10900	Elt.getInt().flipAllBits();
10901	return Elt;
10902	case UO_LNot: {
10903	if (Elt.getKind() == APValue::Int) {
10904	Elt.getInt() = !Elt.getInt();
10905	// operator ! on vectors returns -1 for 'truth', so negate it.
10906	Elt.getInt().negate();
10907	return Elt;
10908	}
10909	assert(Elt.getKind() == APValue::Float &&
10910	"Vector can only be int or float type");
10911	// Float types result in an int of the same size, but -1 for true, or 0 for
10912	// false.
10913	APSInt EltResult{Ctx.getIntWidth(T: ResultTy),
10914	ResultTy->isUnsignedIntegerType()};
10915	if (Elt.getFloat().isZero())
10916	EltResult.setAllBits();
10917	else
10918	EltResult.clearAllBits();
10919
10920	return APValue{EltResult};
10921	}
10922	default:
10923	// FIXME: Implement the rest of the unary operators.
10924	return std::nullopt;
10925	}
10926	}
10927
10928	bool VectorExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
10929	Expr *SubExpr = E->getSubExpr();
10930	const auto *VD = SubExpr->getType()->castAs<VectorType>();
10931	// This result element type differs in the case of negating a floating point
10932	// vector, since the result type is the a vector of the equivilant sized
10933	// integer.
10934	const QualType ResultEltTy = VD->getElementType();
10935	UnaryOperatorKind Op = E->getOpcode();
10936
10937	APValue SubExprValue;
10938	if (!Evaluate(Result&: SubExprValue, Info, E: SubExpr))
10939	return false;
10940
10941	// FIXME: This vector evaluator someday needs to be changed to be LValue
10942	// aware/keep LValue information around, rather than dealing with just vector
10943	// types directly. Until then, we cannot handle cases where the operand to
10944	// these unary operators is an LValue. The only case I've been able to see
10945	// cause this is operator++ assigning to a member expression (only valid in
10946	// altivec compilations) in C mode, so this shouldn't limit us too much.
10947	if (SubExprValue.isLValue())
10948	return false;
10949
10950	assert(SubExprValue.getVectorLength() == VD->getNumElements() &&
10951	"Vector length doesn't match type?");
10952
10953	SmallVector<APValue, 4> ResultElements;
10954	for (unsigned EltNum = 0; EltNum < VD->getNumElements(); ++EltNum) {
10955	std::optional<APValue> Elt = handleVectorUnaryOperator(
10956	Ctx&: Info.Ctx, ResultTy: ResultEltTy, Op, Elt: SubExprValue.getVectorElt(I: EltNum));
10957	if (!Elt)
10958	return false;
10959	ResultElements.push_back(Elt: *Elt);
10960	}
10961	return Success(APValue(ResultElements.data(), ResultElements.size()), E);
10962	}
10963
10964	//===----------------------------------------------------------------------===//
10965	// Array Evaluation
10966	//===----------------------------------------------------------------------===//
10967
10968	namespace {
10969	class ArrayExprEvaluator
10970	: public ExprEvaluatorBase<ArrayExprEvaluator> {
10971	const LValue &This;
10972	APValue &Result;
10973	public:
10974
10975	ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
10976	: ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
10977
10978	bool Success(const APValue &V, const Expr *E) {
10979	assert(V.isArray() && "expected array");
10980	Result = V;
10981	return true;
10982	}
10983
10984	bool ZeroInitialization(const Expr *E) {
10985	const ConstantArrayType *CAT =
10986	Info.Ctx.getAsConstantArrayType(T: E->getType());
10987	if (!CAT) {
10988	if (E->getType()->isIncompleteArrayType()) {
10989	// We can be asked to zero-initialize a flexible array member; this
10990	// is represented as an ImplicitValueInitExpr of incomplete array
10991	// type. In this case, the array has zero elements.
10992	Result = APValue(APValue::UninitArray(), 0, 0);
10993	return true;
10994	}
10995	// FIXME: We could handle VLAs here.
10996	return Error(E);
10997	}
10998
10999	Result = APValue(APValue::UninitArray(), 0, CAT->getZExtSize());
11000	if (!Result.hasArrayFiller())
11001	return true;
11002
11003	// Zero-initialize all elements.
11004	LValue Subobject = This;
11005	Subobject.addArray(Info, E, CAT);
11006	ImplicitValueInitExpr VIE(CAT->getElementType());
11007	return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
11008	}
11009
11010	bool VisitCallExpr(const CallExpr *E) {
11011	return handleCallExpr(E, Result, ResultSlot: &This);
11012	}
11013	bool VisitInitListExpr(const InitListExpr *E,
11014	QualType AllocType = QualType());
11015	bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
11016	bool VisitCXXConstructExpr(const CXXConstructExpr *E);
11017	bool VisitCXXConstructExpr(const CXXConstructExpr *E,
11018	const LValue &Subobject,
11019	APValue *Value, QualType Type);
11020	bool VisitStringLiteral(const StringLiteral *E,
11021	QualType AllocType = QualType()) {
11022	expandStringLiteral(Info, S: E, Result, AllocType);
11023	return true;
11024	}
11025	bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E);
11026	bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit,
11027	ArrayRef<Expr *> Args,
11028	const Expr *ArrayFiller,
11029	QualType AllocType = QualType());
11030	};
11031	} // end anonymous namespace
11032
11033	static bool EvaluateArray(const Expr *E, const LValue &This,
11034	APValue &Result, EvalInfo &Info) {
11035	assert(!E->isValueDependent());
11036	assert(E->isPRValue() && E->getType()->isArrayType() &&
11037	"not an array prvalue");
11038	return ArrayExprEvaluator(Info, This, Result).Visit(E);
11039	}
11040
11041	static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
11042	APValue &Result, const InitListExpr *ILE,
11043	QualType AllocType) {
11044	assert(!ILE->isValueDependent());
11045	assert(ILE->isPRValue() && ILE->getType()->isArrayType() &&
11046	"not an array prvalue");
11047	return ArrayExprEvaluator(Info, This, Result)
11048	.VisitInitListExpr(E: ILE, AllocType);
11049	}
11050
11051	static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
11052	APValue &Result,
11053	const CXXConstructExpr *CCE,
11054	QualType AllocType) {
11055	assert(!CCE->isValueDependent());
11056	assert(CCE->isPRValue() && CCE->getType()->isArrayType() &&
11057	"not an array prvalue");
11058	return ArrayExprEvaluator(Info, This, Result)
11059	.VisitCXXConstructExpr(E: CCE, Subobject: This, Value: &Result, Type: AllocType);
11060	}
11061
11062	// Return true iff the given array filler may depend on the element index.
11063	static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
11064	// For now, just allow non-class value-initialization and initialization
11065	// lists comprised of them.
11066	if (isa<ImplicitValueInitExpr>(Val: FillerExpr))
11067	return false;
11068	if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Val: FillerExpr)) {
11069	for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
11070	if (MaybeElementDependentArrayFiller(FillerExpr: ILE->getInit(Init: I)))
11071	return true;
11072	}
11073
11074	if (ILE->hasArrayFiller() &&
11075	MaybeElementDependentArrayFiller(FillerExpr: ILE->getArrayFiller()))
11076	return true;
11077
11078	return false;
11079	}
11080	return true;
11081	}
11082
11083	bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
11084	QualType AllocType) {
11085	const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
11086	T: AllocType.isNull() ? E->getType() : AllocType);
11087	if (!CAT)
11088	return Error(E);
11089
11090	// C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
11091	// an appropriately-typed string literal enclosed in braces.
11092	if (E->isStringLiteralInit()) {
11093	auto *SL = dyn_cast<StringLiteral>(Val: E->getInit(Init: 0)->IgnoreParenImpCasts());
11094	// FIXME: Support ObjCEncodeExpr here once we support it in
11095	// ArrayExprEvaluator generally.
11096	if (!SL)
11097	return Error(E);
11098	return VisitStringLiteral(E: SL, AllocType);
11099	}
11100	// Any other transparent list init will need proper handling of the
11101	// AllocType; we can't just recurse to the inner initializer.
11102	assert(!E->isTransparent() &&
11103	"transparent array list initialization is not string literal init?");
11104
11105	return VisitCXXParenListOrInitListExpr(E, E->inits(), E->getArrayFiller(),
11106	AllocType);
11107	}
11108
11109	bool ArrayExprEvaluator::VisitCXXParenListOrInitListExpr(
11110	const Expr *ExprToVisit, ArrayRef<Expr *> Args, const Expr *ArrayFiller,
11111	QualType AllocType) {
11112	const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
11113	T: AllocType.isNull() ? ExprToVisit->getType() : AllocType);
11114
11115	bool Success = true;
11116
11117	assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
11118	"zero-initialized array shouldn't have any initialized elts");
11119	APValue Filler;
11120	if (Result.isArray() && Result.hasArrayFiller())
11121	Filler = Result.getArrayFiller();
11122
11123	unsigned NumEltsToInit = Args.size();
11124	unsigned NumElts = CAT->getZExtSize();
11125
11126	// If the initializer might depend on the array index, run it for each
11127	// array element.
11128	if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr: ArrayFiller))
11129	NumEltsToInit = NumElts;
11130
11131	LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "
11132	<< NumEltsToInit << ".\n");
11133
11134	Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
11135
11136	// If the array was previously zero-initialized, preserve the
11137	// zero-initialized values.
11138	if (Filler.hasValue()) {
11139	for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
11140	Result.getArrayInitializedElt(I) = Filler;
11141	if (Result.hasArrayFiller())
11142	Result.getArrayFiller() = Filler;
11143	}
11144
11145	LValue Subobject = This;
11146	Subobject.addArray(Info, E: ExprToVisit, CAT);
11147	for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
11148	const Expr *Init = Index < Args.size() ? Args[Index] : ArrayFiller;
11149	if (!EvaluateInPlace(Result&: Result.getArrayInitializedElt(I: Index),
11150	Info, This: Subobject, E: Init) ||
11151	!HandleLValueArrayAdjustment(Info, Init, Subobject,
11152	CAT->getElementType(), 1)) {
11153	if (!Info.noteFailure())
11154	return false;
11155	Success = false;
11156	}
11157	}
11158
11159	if (!Result.hasArrayFiller())
11160	return Success;
11161
11162	// If we get here, we have a trivial filler, which we can just evaluate
11163	// once and splat over the rest of the array elements.
11164	assert(ArrayFiller && "no array filler for incomplete init list");
11165	return EvaluateInPlace(Result&: Result.getArrayFiller(), Info, This: Subobject,
11166	E: ArrayFiller) &&
11167	Success;
11168	}
11169
11170	bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
11171	LValue CommonLV;
11172	if (E->getCommonExpr() &&
11173	!Evaluate(Result&: Info.CurrentCall->createTemporary(
11174	Key: E->getCommonExpr(),
11175	T: getStorageType(Info.Ctx, E->getCommonExpr()),
11176	Scope: ScopeKind::FullExpression, LV&: CommonLV),
11177	Info, E: E->getCommonExpr()->getSourceExpr()))
11178	return false;
11179
11180	auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
11181
11182	uint64_t Elements = CAT->getZExtSize();
11183	Result = APValue(APValue::UninitArray(), Elements, Elements);
11184
11185	LValue Subobject = This;
11186	Subobject.addArray(Info, E, CAT: CAT);
11187
11188	bool Success = true;
11189	for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
11190	// C++ [class.temporary]/5
11191	// There are four contexts in which temporaries are destroyed at a different
11192	// point than the end of the full-expression. [...] The second context is
11193	// when a copy constructor is called to copy an element of an array while
11194	// the entire array is copied [...]. In either case, if the constructor has
11195	// one or more default arguments, the destruction of every temporary created
11196	// in a default argument is sequenced before the construction of the next
11197	// array element, if any.
11198	FullExpressionRAII Scope(Info);
11199
11200	if (!EvaluateInPlace(Result&: Result.getArrayInitializedElt(I: Index),
11201	Info, This: Subobject, E: E->getSubExpr()) ||
11202	!HandleLValueArrayAdjustment(Info, E, Subobject,
11203	CAT->getElementType(), 1)) {
11204	if (!Info.noteFailure())
11205	return false;
11206	Success = false;
11207	}
11208
11209	// Make sure we run the destructors too.
11210	Scope.destroy();
11211	}
11212
11213	return Success;
11214	}
11215
11216	bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
11217	return VisitCXXConstructExpr(E, This, &Result, E->getType());
11218	}
11219
11220	bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
11221	const LValue &Subobject,
11222	APValue *Value,
11223	QualType Type) {
11224	bool HadZeroInit = Value->hasValue();
11225
11226	if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T: Type)) {
11227	unsigned FinalSize = CAT->getZExtSize();
11228
11229	// Preserve the array filler if we had prior zero-initialization.
11230	APValue Filler =
11231	HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
11232	: APValue();
11233
11234	*Value = APValue(APValue::UninitArray(), 0, FinalSize);
11235	if (FinalSize == 0)
11236	return true;
11237
11238	bool HasTrivialConstructor = CheckTrivialDefaultConstructor(
11239	Info, E->getExprLoc(), E->getConstructor(),
11240	E->requiresZeroInitialization());
11241	LValue ArrayElt = Subobject;
11242	ArrayElt.addArray(Info, E, CAT);
11243	// We do the whole initialization in two passes, first for just one element,
11244	// then for the whole array. It's possible we may find out we can't do const
11245	// init in the first pass, in which case we avoid allocating a potentially
11246	// large array. We don't do more passes because expanding array requires
11247	// copying the data, which is wasteful.
11248	for (const unsigned N : {1u, FinalSize}) {
11249	unsigned OldElts = Value->getArrayInitializedElts();
11250	if (OldElts == N)
11251	break;
11252
11253	// Expand the array to appropriate size.
11254	APValue NewValue(APValue::UninitArray(), N, FinalSize);
11255	for (unsigned I = 0; I < OldElts; ++I)
11256	NewValue.getArrayInitializedElt(I).swap(
11257	RHS&: Value->getArrayInitializedElt(I));
11258	Value->swap(RHS&: NewValue);
11259
11260	if (HadZeroInit)
11261	for (unsigned I = OldElts; I < N; ++I)
11262	Value->getArrayInitializedElt(I) = Filler;
11263
11264	if (HasTrivialConstructor && N == FinalSize && FinalSize != 1) {
11265	// If we have a trivial constructor, only evaluate it once and copy
11266	// the result into all the array elements.
11267	APValue &FirstResult = Value->getArrayInitializedElt(I: 0);
11268	for (unsigned I = OldElts; I < FinalSize; ++I)
11269	Value->getArrayInitializedElt(I) = FirstResult;
11270	} else {
11271	for (unsigned I = OldElts; I < N; ++I) {
11272	if (!VisitCXXConstructExpr(E, ArrayElt,
11273	&Value->getArrayInitializedElt(I),
11274	CAT->getElementType()) ||
11275	!HandleLValueArrayAdjustment(Info, E, ArrayElt,
11276	CAT->getElementType(), 1))
11277	return false;
11278	// When checking for const initilization any diagnostic is considered
11279	// an error.
11280	if (Info.EvalStatus.Diag && !Info.EvalStatus.Diag->empty() &&
11281	!Info.keepEvaluatingAfterFailure())
11282	return false;
11283	}
11284	}
11285	}
11286
11287	return true;
11288	}
11289
11290	if (!Type->isRecordType())
11291	return Error(E);
11292
11293	return RecordExprEvaluator(Info, Subobject, *Value)
11294	.VisitCXXConstructExpr(E, T: Type);
11295	}
11296
11297	bool ArrayExprEvaluator::VisitCXXParenListInitExpr(
11298	const CXXParenListInitExpr *E) {
11299	assert(dyn_cast<ConstantArrayType>(E->getType()) &&
11300	"Expression result is not a constant array type");
11301
11302	return VisitCXXParenListOrInitListExpr(E, E->getInitExprs(),
11303	E->getArrayFiller());
11304	}
11305
11306	//===----------------------------------------------------------------------===//
11307	// Integer Evaluation
11308	//
11309	// As a GNU extension, we support casting pointers to sufficiently-wide integer
11310	// types and back in constant folding. Integer values are thus represented
11311	// either as an integer-valued APValue, or as an lvalue-valued APValue.
11312	//===----------------------------------------------------------------------===//
11313
11314	namespace {
11315	class IntExprEvaluator
11316	: public ExprEvaluatorBase<IntExprEvaluator> {
11317	APValue &Result;
11318	public:
11319	IntExprEvaluator(EvalInfo &info, APValue &result)
11320	: ExprEvaluatorBaseTy(info), Result(result) {}
11321
11322	bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
11323	assert(E->getType()->isIntegralOrEnumerationType() &&
11324	"Invalid evaluation result.");
11325	assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
11326	"Invalid evaluation result.");
11327	assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
11328	"Invalid evaluation result.");
11329	Result = APValue(SI);
11330	return true;
11331	}
11332	bool Success(const llvm::APSInt &SI, const Expr *E) {
11333	return Success(SI, E, Result);
11334	}
11335
11336	bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
11337	assert(E->getType()->isIntegralOrEnumerationType() &&
11338	"Invalid evaluation result.");
11339	assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
11340	"Invalid evaluation result.");
11341	Result = APValue(APSInt(I));
11342	Result.getInt().setIsUnsigned(
11343	E->getType()->isUnsignedIntegerOrEnumerationType());
11344	return true;
11345	}
11346	bool Success(const llvm::APInt &I, const Expr *E) {
11347	return Success(I, E, Result);
11348	}
11349
11350	bool Success(uint64_t Value, const Expr *E, APValue &Result) {
11351	assert(E->getType()->isIntegralOrEnumerationType() &&
11352	"Invalid evaluation result.");
11353	Result = APValue(Info.Ctx.MakeIntValue(Value, Type: E->getType()));
11354	return true;
11355	}
11356	bool Success(uint64_t Value, const Expr *E) {
11357	return Success(Value, E, Result);
11358	}
11359
11360	bool Success(CharUnits Size, const Expr *E) {
11361	return Success(Value: Size.getQuantity(), E);
11362	}
11363
11364	bool Success(const APValue &V, const Expr *E) {
11365	if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) {
11366	Result = V;
11367	return true;
11368	}
11369	return Success(SI: V.getInt(), E);
11370	}
11371
11372	bool ZeroInitialization(const Expr *E) { return Success(Value: 0, E); }
11373
11374	//===--------------------------------------------------------------------===//
11375	// Visitor Methods
11376	//===--------------------------------------------------------------------===//
11377
11378	bool VisitIntegerLiteral(const IntegerLiteral *E) {
11379	return Success(E->getValue(), E);
11380	}
11381	bool VisitCharacterLiteral(const CharacterLiteral *E) {
11382	return Success(E->getValue(), E);
11383	}
11384
11385	bool CheckReferencedDecl(const Expr *E, const Decl *D);
11386	bool VisitDeclRefExpr(const DeclRefExpr *E) {
11387	if (CheckReferencedDecl(E, E->getDecl()))
11388	return true;
11389
11390	return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
11391	}
11392	bool VisitMemberExpr(const MemberExpr *E) {
11393	if (CheckReferencedDecl(E, E->getMemberDecl())) {
11394	VisitIgnoredBaseExpression(E: E->getBase());
11395	return true;
11396	}
11397
11398	return ExprEvaluatorBaseTy::VisitMemberExpr(E);
11399	}
11400
11401	bool VisitCallExpr(const CallExpr *E);
11402	bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
11403	bool VisitBinaryOperator(const BinaryOperator *E);
11404	bool VisitOffsetOfExpr(const OffsetOfExpr *E);
11405	bool VisitUnaryOperator(const UnaryOperator *E);
11406
11407	bool VisitCastExpr(const CastExpr* E);
11408	bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
11409
11410	bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
11411	return Success(E->getValue(), E);
11412	}
11413
11414	bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
11415	return Success(E->getValue(), E);
11416	}
11417
11418	bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
11419	if (Info.ArrayInitIndex == uint64_t(-1)) {
11420	// We were asked to evaluate this subexpression independent of the
11421	// enclosing ArrayInitLoopExpr. We can't do that.
11422	Info.FFDiag(E);
11423	return false;
11424	}
11425	return Success(Info.ArrayInitIndex, E);
11426	}
11427
11428	// Note, GNU defines __null as an integer, not a pointer.
11429	bool VisitGNUNullExpr(const GNUNullExpr *E) {
11430	return ZeroInitialization(E);
11431	}
11432
11433	bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
11434	return Success(E->getValue(), E);
11435	}
11436
11437	bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
11438	return Success(E->getValue(), E);
11439	}
11440
11441	bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
11442	return Success(E->getValue(), E);
11443	}
11444
11445	bool VisitUnaryReal(const UnaryOperator *E);
11446	bool VisitUnaryImag(const UnaryOperator *E);
11447
11448	bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
11449	bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
11450	bool VisitSourceLocExpr(const SourceLocExpr *E);
11451	bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
11452	bool VisitRequiresExpr(const RequiresExpr *E);
11453	// FIXME: Missing: array subscript of vector, member of vector
11454	};
11455
11456	class FixedPointExprEvaluator
11457	: public ExprEvaluatorBase<FixedPointExprEvaluator> {
11458	APValue &Result;
11459
11460	public:
11461	FixedPointExprEvaluator(EvalInfo &info, APValue &result)
11462	: ExprEvaluatorBaseTy(info), Result(result) {}
11463
11464	bool Success(const llvm::APInt &I, const Expr *E) {
11465	return Success(
11466	V: APFixedPoint(I, Info.Ctx.getFixedPointSemantics(Ty: E->getType())), E);
11467	}
11468
11469	bool Success(uint64_t Value, const Expr *E) {
11470	return Success(
11471	V: APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(Ty: E->getType())), E);
11472	}
11473
11474	bool Success(const APValue &V, const Expr *E) {
11475	return Success(V: V.getFixedPoint(), E);
11476	}
11477
11478	bool Success(const APFixedPoint &V, const Expr *E) {
11479	assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
11480	assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&
11481	"Invalid evaluation result.");
11482	Result = APValue(V);
11483	return true;
11484	}
11485
11486	bool ZeroInitialization(const Expr *E) {
11487	return Success(Value: 0, E);
11488	}
11489
11490	//===--------------------------------------------------------------------===//
11491	// Visitor Methods
11492	//===--------------------------------------------------------------------===//
11493
11494	bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
11495	return Success(E->getValue(), E);
11496	}
11497
11498	bool VisitCastExpr(const CastExpr *E);
11499	bool VisitUnaryOperator(const UnaryOperator *E);
11500	bool VisitBinaryOperator(const BinaryOperator *E);
11501	};
11502	} // end anonymous namespace
11503
11504	/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
11505	/// produce either the integer value or a pointer.
11506	///
11507	/// GCC has a heinous extension which folds casts between pointer types and
11508	/// pointer-sized integral types. We support this by allowing the evaluation of
11509	/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
11510	/// Some simple arithmetic on such values is supported (they are treated much
11511	/// like char*).
11512	static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
11513	EvalInfo &Info) {
11514	assert(!E->isValueDependent());
11515	assert(E->isPRValue() && E->getType()->isIntegralOrEnumerationType());
11516	return IntExprEvaluator(Info, Result).Visit(E);
11517	}
11518
11519	static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
11520	assert(!E->isValueDependent());
11521	APValue Val;
11522	if (!EvaluateIntegerOrLValue(E, Result&: Val, Info))
11523	return false;
11524	if (!Val.isInt()) {
11525	// FIXME: It would be better to produce the diagnostic for casting
11526	// a pointer to an integer.
11527	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
11528	return false;
11529	}
11530	Result = Val.getInt();
11531	return true;
11532	}
11533
11534	bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
11535	APValue Evaluated = E->EvaluateInContext(
11536	Ctx: Info.Ctx, DefaultExpr: Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
11537	return Success(Evaluated, E);
11538	}
11539
11540	static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
11541	EvalInfo &Info) {
11542	assert(!E->isValueDependent());
11543	if (E->getType()->isFixedPointType()) {
11544	APValue Val;
11545	if (!FixedPointExprEvaluator(Info, Val).Visit(E))
11546	return false;
11547	if (!Val.isFixedPoint())
11548	return false;
11549
11550	Result = Val.getFixedPoint();
11551	return true;
11552	}
11553	return false;
11554	}
11555
11556	static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
11557	EvalInfo &Info) {
11558	assert(!E->isValueDependent());
11559	if (E->getType()->isIntegerType()) {
11560	auto FXSema = Info.Ctx.getFixedPointSemantics(Ty: E->getType());
11561	APSInt Val;
11562	if (!EvaluateInteger(E, Result&: Val, Info))
11563	return false;
11564	Result = APFixedPoint(Val, FXSema);
11565	return true;
11566	} else if (E->getType()->isFixedPointType()) {
11567	return EvaluateFixedPoint(E, Result, Info);
11568	}
11569	return false;
11570	}
11571
11572	/// Check whether the given declaration can be directly converted to an integral
11573	/// rvalue. If not, no diagnostic is produced; there are other things we can
11574	/// try.
11575	bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
11576	// Enums are integer constant exprs.
11577	if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(Val: D)) {
11578	// Check for signedness/width mismatches between E type and ECD value.
11579	bool SameSign = (ECD->getInitVal().isSigned()
11580	== E->getType()->isSignedIntegerOrEnumerationType());
11581	bool SameWidth = (ECD->getInitVal().getBitWidth()
11582	== Info.Ctx.getIntWidth(T: E->getType()));
11583	if (SameSign && SameWidth)
11584	return Success(SI: ECD->getInitVal(), E);
11585	else {
11586	// Get rid of mismatch (otherwise Success assertions will fail)
11587	// by computing a new value matching the type of E.
11588	llvm::APSInt Val = ECD->getInitVal();
11589	if (!SameSign)
11590	Val.setIsSigned(!ECD->getInitVal().isSigned());
11591	if (!SameWidth)
11592	Val = Val.extOrTrunc(width: Info.Ctx.getIntWidth(T: E->getType()));
11593	return Success(SI: Val, E);
11594	}
11595	}
11596	return false;
11597	}
11598
11599	/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
11600	/// as GCC.
11601	GCCTypeClass EvaluateBuiltinClassifyType(QualType T,
11602	const LangOptions &LangOpts) {
11603	assert(!T->isDependentType() && "unexpected dependent type");
11604
11605	QualType CanTy = T.getCanonicalType();
11606
11607	switch (CanTy->getTypeClass()) {
11608	#define TYPE(ID, BASE)
11609	#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
11610	#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
11611	#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
11612	#include "clang/AST/TypeNodes.inc"
11613	case Type::Auto:
11614	case Type::DeducedTemplateSpecialization:
11615	llvm_unreachable("unexpected non-canonical or dependent type");
11616
11617	case Type::Builtin:
11618	switch (cast<BuiltinType>(CanTy)->getKind()) {
11619	#define BUILTIN_TYPE(ID, SINGLETON_ID)
11620	#define SIGNED_TYPE(ID, SINGLETON_ID) \
11621	case BuiltinType::ID: return GCCTypeClass::Integer;
11622	#define FLOATING_TYPE(ID, SINGLETON_ID) \
11623	case BuiltinType::ID: return GCCTypeClass::RealFloat;
11624	#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
11625	case BuiltinType::ID: break;
11626	#include "clang/AST/BuiltinTypes.def"
11627	case BuiltinType::Void:
11628	return GCCTypeClass::Void;
11629
11630	case BuiltinType::Bool:
11631	return GCCTypeClass::Bool;
11632
11633	case BuiltinType::Char_U:
11634	case BuiltinType::UChar:
11635	case BuiltinType::WChar_U:
11636	case BuiltinType::Char8:
11637	case BuiltinType::Char16:
11638	case BuiltinType::Char32:
11639	case BuiltinType::UShort:
11640	case BuiltinType::UInt:
11641	case BuiltinType::ULong:
11642	case BuiltinType::ULongLong:
11643	case BuiltinType::UInt128:
11644	return GCCTypeClass::Integer;
11645
11646	case BuiltinType::UShortAccum:
11647	case BuiltinType::UAccum:
11648	case BuiltinType::ULongAccum:
11649	case BuiltinType::UShortFract:
11650	case BuiltinType::UFract:
11651	case BuiltinType::ULongFract:
11652	case BuiltinType::SatUShortAccum:
11653	case BuiltinType::SatUAccum:
11654	case BuiltinType::SatULongAccum:
11655	case BuiltinType::SatUShortFract:
11656	case BuiltinType::SatUFract:
11657	case BuiltinType::SatULongFract:
11658	return GCCTypeClass::None;
11659
11660	case BuiltinType::NullPtr:
11661
11662	case BuiltinType::ObjCId:
11663	case BuiltinType::ObjCClass:
11664	case BuiltinType::ObjCSel:
11665	#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
11666	case BuiltinType::Id:
11667	#include "clang/Basic/OpenCLImageTypes.def"
11668	#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
11669	case BuiltinType::Id:
11670	#include "clang/Basic/OpenCLExtensionTypes.def"
11671	case BuiltinType::OCLSampler:
11672	case BuiltinType::OCLEvent:
11673	case BuiltinType::OCLClkEvent:
11674	case BuiltinType::OCLQueue:
11675	case BuiltinType::OCLReserveID:
11676	#define SVE_TYPE(Name, Id, SingletonId) \
11677	case BuiltinType::Id:
11678	#include "clang/Basic/AArch64SVEACLETypes.def"
11679	#define PPC_VECTOR_TYPE(Name, Id, Size) \
11680	case BuiltinType::Id:
11681	#include "clang/Basic/PPCTypes.def"
11682	#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
11683	#include "clang/Basic/RISCVVTypes.def"
11684	#define WASM_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
11685	#include "clang/Basic/WebAssemblyReferenceTypes.def"
11686	return GCCTypeClass::None;
11687
11688	case BuiltinType::Dependent:
11689	llvm_unreachable("unexpected dependent type");
11690	};
11691	llvm_unreachable("unexpected placeholder type");
11692
11693	case Type::Enum:
11694	return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;
11695
11696	case Type::Pointer:
11697	case Type::ConstantArray:
11698	case Type::VariableArray:
11699	case Type::IncompleteArray:
11700	case Type::FunctionNoProto:
11701	case Type::FunctionProto:
11702	case Type::ArrayParameter:
11703	return GCCTypeClass::Pointer;
11704
11705	case Type::MemberPointer:
11706	return CanTy->isMemberDataPointerType()
11707	? GCCTypeClass::PointerToDataMember
11708	: GCCTypeClass::PointerToMemberFunction;
11709
11710	case Type::Complex:
11711	return GCCTypeClass::Complex;
11712
11713	case Type::Record:
11714	return CanTy->isUnionType() ? GCCTypeClass::Union
11715	: GCCTypeClass::ClassOrStruct;
11716
11717	case Type::Atomic:
11718	// GCC classifies _Atomic T the same as T.
11719	return EvaluateBuiltinClassifyType(
11720	CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
11721
11722	case Type::Vector:
11723	case Type::ExtVector:
11724	return GCCTypeClass::Vector;
11725
11726	case Type::BlockPointer:
11727	case Type::ConstantMatrix:
11728	case Type::ObjCObject:
11729	case Type::ObjCInterface:
11730	case Type::ObjCObjectPointer:
11731	case Type::Pipe:
11732	// Classify all other types that don't fit into the regular
11733	// classification the same way.
11734	return GCCTypeClass::None;
11735
11736	case Type::BitInt:
11737	return GCCTypeClass::BitInt;
11738
11739	case Type::LValueReference:
11740	case Type::RValueReference:
11741	llvm_unreachable("invalid type for expression");
11742	}
11743
11744	llvm_unreachable("unexpected type class");
11745	}
11746
11747	/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
11748	/// as GCC.
11749	static GCCTypeClass
11750	EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
11751	// If no argument was supplied, default to None. This isn't
11752	// ideal, however it is what gcc does.
11753	if (E->getNumArgs() == 0)
11754	return GCCTypeClass::None;
11755
11756	// FIXME: Bizarrely, GCC treats a call with more than one argument as not
11757	// being an ICE, but still folds it to a constant using the type of the first
11758	// argument.
11759	return EvaluateBuiltinClassifyType(T: E->getArg(Arg: 0)->getType(), LangOpts);
11760	}
11761
11762	/// EvaluateBuiltinConstantPForLValue - Determine the result of
11763	/// __builtin_constant_p when applied to the given pointer.
11764	///
11765	/// A pointer is only "constant" if it is null (or a pointer cast to integer)
11766	/// or it points to the first character of a string literal.
11767	static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
11768	APValue::LValueBase Base = LV.getLValueBase();
11769	if (Base.isNull()) {
11770	// A null base is acceptable.
11771	return true;
11772	} else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
11773	if (!isa<StringLiteral>(Val: E))
11774	return false;
11775	return LV.getLValueOffset().isZero();
11776	} else if (Base.is<TypeInfoLValue>()) {
11777	// Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
11778	// evaluate to true.
11779	return true;
11780	} else {
11781	// Any other base is not constant enough for GCC.
11782	return false;
11783	}
11784	}
11785
11786	/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
11787	/// GCC as we can manage.
11788	static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
11789	// This evaluation is not permitted to have side-effects, so evaluate it in
11790	// a speculative evaluation context.
11791	SpeculativeEvaluationRAII SpeculativeEval(Info);
11792
11793	// Constant-folding is always enabled for the operand of __builtin_constant_p
11794	// (even when the enclosing evaluation context otherwise requires a strict
11795	// language-specific constant expression).
11796	FoldConstant Fold(Info, true);
11797
11798	QualType ArgType = Arg->getType();
11799
11800	// __builtin_constant_p always has one operand. The rules which gcc follows
11801	// are not precisely documented, but are as follows:
11802	//
11803	// - If the operand is of integral, floating, complex or enumeration type,
11804	// and can be folded to a known value of that type, it returns 1.
11805	// - If the operand can be folded to a pointer to the first character
11806	// of a string literal (or such a pointer cast to an integral type)
11807	// or to a null pointer or an integer cast to a pointer, it returns 1.
11808	//
11809	// Otherwise, it returns 0.
11810	//
11811	// FIXME: GCC also intends to return 1 for literals of aggregate types, but
11812	// its support for this did not work prior to GCC 9 and is not yet well
11813	// understood.
11814	if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
11815	ArgType->isAnyComplexType() || ArgType->isPointerType() ||
11816	ArgType->isNullPtrType()) {
11817	APValue V;
11818	if (!::EvaluateAsRValue(Info, E: Arg, Result&: V) || Info.EvalStatus.HasSideEffects) {
11819	Fold.keepDiagnostics();
11820	return false;
11821	}
11822
11823	// For a pointer (possibly cast to integer), there are special rules.
11824	if (V.getKind() == APValue::LValue)
11825	return EvaluateBuiltinConstantPForLValue(LV: V);
11826
11827	// Otherwise, any constant value is good enough.
11828	return V.hasValue();
11829	}
11830
11831	// Anything else isn't considered to be sufficiently constant.
11832	return false;
11833	}
11834
11835	/// Retrieves the "underlying object type" of the given expression,
11836	/// as used by __builtin_object_size.
11837	static QualType getObjectType(APValue::LValueBase B) {
11838	if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
11839	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: D))
11840	return VD->getType();
11841	} else if (const Expr *E = B.dyn_cast<const Expr*>()) {
11842	if (isa<CompoundLiteralExpr>(Val: E))
11843	return E->getType();
11844	} else if (B.is<TypeInfoLValue>()) {
11845	return B.getTypeInfoType();
11846	} else if (B.is<DynamicAllocLValue>()) {
11847	return B.getDynamicAllocType();
11848	}
11849
11850	return QualType();
11851	}
11852
11853	/// A more selective version of E->IgnoreParenCasts for
11854	/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
11855	/// to change the type of E.
11856	/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
11857	///
11858	/// Always returns an RValue with a pointer representation.
11859	static const Expr *ignorePointerCastsAndParens(const Expr *E) {
11860	assert(E->isPRValue() && E->getType()->hasPointerRepresentation());
11861
11862	const Expr *NoParens = E->IgnoreParens();
11863	const auto *Cast = dyn_cast<CastExpr>(Val: NoParens);
11864	if (Cast == nullptr)
11865	return NoParens;
11866
11867	// We only conservatively allow a few kinds of casts, because this code is
11868	// inherently a simple solution that seeks to support the common case.
11869	auto CastKind = Cast->getCastKind();
11870	if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
11871	CastKind != CK_AddressSpaceConversion)
11872	return NoParens;
11873
11874	const auto *SubExpr = Cast->getSubExpr();
11875	if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isPRValue())
11876	return NoParens;
11877	return ignorePointerCastsAndParens(E: SubExpr);
11878	}
11879
11880	/// Checks to see if the given LValue's Designator is at the end of the LValue's
11881	/// record layout. e.g.
11882	/// struct { struct { int a, b; } fst, snd; } obj;
11883	/// obj.fst // no
11884	/// obj.snd // yes
11885	/// obj.fst.a // no
11886	/// obj.fst.b // no
11887	/// obj.snd.a // no
11888	/// obj.snd.b // yes
11889	///
11890	/// Please note: this function is specialized for how __builtin_object_size
11891	/// views "objects".
11892	///
11893	/// If this encounters an invalid RecordDecl or otherwise cannot determine the
11894	/// correct result, it will always return true.
11895	static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
11896	assert(!LVal.Designator.Invalid);
11897
11898	auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
11899	const RecordDecl *Parent = FD->getParent();
11900	Invalid = Parent->isInvalidDecl();
11901	if (Invalid || Parent->isUnion())
11902	return true;
11903	const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(D: Parent);
11904	return FD->getFieldIndex() + 1 == Layout.getFieldCount();
11905	};
11906
11907	auto &Base = LVal.getLValueBase();
11908	if (auto *ME = dyn_cast_or_null<MemberExpr>(Val: Base.dyn_cast<const Expr *>())) {
11909	if (auto *FD = dyn_cast<FieldDecl>(Val: ME->getMemberDecl())) {
11910	bool Invalid;
11911	if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11912	return Invalid;
11913	} else if (auto *IFD = dyn_cast<IndirectFieldDecl>(Val: ME->getMemberDecl())) {
11914	for (auto *FD : IFD->chain()) {
11915	bool Invalid;
11916	if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(Val: FD), Invalid))
11917	return Invalid;
11918	}
11919	}
11920	}
11921
11922	unsigned I = 0;
11923	QualType BaseType = getType(B: Base);
11924	if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
11925	// If we don't know the array bound, conservatively assume we're looking at
11926	// the final array element.
11927	++I;
11928	if (BaseType->isIncompleteArrayType())
11929	BaseType = Ctx.getAsArrayType(T: BaseType)->getElementType();
11930	else
11931	BaseType = BaseType->castAs<PointerType>()->getPointeeType();
11932	}
11933
11934	for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
11935	const auto &Entry = LVal.Designator.Entries[I];
11936	if (BaseType->isArrayType()) {
11937	// Because __builtin_object_size treats arrays as objects, we can ignore
11938	// the index iff this is the last array in the Designator.
11939	if (I + 1 == E)
11940	return true;
11941	const auto *CAT = cast<ConstantArrayType>(Val: Ctx.getAsArrayType(T: BaseType));
11942	uint64_t Index = Entry.getAsArrayIndex();
11943	if (Index + 1 != CAT->getZExtSize())
11944	return false;
11945	BaseType = CAT->getElementType();
11946	} else if (BaseType->isAnyComplexType()) {
11947	const auto *CT = BaseType->castAs<ComplexType>();
11948	uint64_t Index = Entry.getAsArrayIndex();
11949	if (Index != 1)
11950	return false;
11951	BaseType = CT->getElementType();
11952	} else if (auto *FD = getAsField(Entry)) {
11953	bool Invalid;
11954	if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11955	return Invalid;
11956	BaseType = FD->getType();
11957	} else {
11958	assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
11959	return false;
11960	}
11961	}
11962	return true;
11963	}
11964
11965	/// Tests to see if the LValue has a user-specified designator (that isn't
11966	/// necessarily valid). Note that this always returns 'true' if the LValue has
11967	/// an unsized array as its first designator entry, because there's currently no
11968	/// way to tell if the user typed *foo or foo[0].
11969	static bool refersToCompleteObject(const LValue &LVal) {
11970	if (LVal.Designator.Invalid)
11971	return false;
11972
11973	if (!LVal.Designator.Entries.empty())
11974	return LVal.Designator.isMostDerivedAnUnsizedArray();
11975
11976	if (!LVal.InvalidBase)
11977	return true;
11978
11979	// If `E` is a MemberExpr, then the first part of the designator is hiding in
11980	// the LValueBase.
11981	const auto *E = LVal.Base.dyn_cast<const Expr *>();
11982	return !E || !isa<MemberExpr>(Val: E);
11983	}
11984
11985	/// Attempts to detect a user writing into a piece of memory that's impossible
11986	/// to figure out the size of by just using types.
11987	static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
11988	const SubobjectDesignator &Designator = LVal.Designator;
11989	// Notes:
11990	// - Users can only write off of the end when we have an invalid base. Invalid
11991	// bases imply we don't know where the memory came from.
11992	// - We used to be a bit more aggressive here; we'd only be conservative if
11993	// the array at the end was flexible, or if it had 0 or 1 elements. This
11994	// broke some common standard library extensions (PR30346), but was
11995	// otherwise seemingly fine. It may be useful to reintroduce this behavior
11996	// with some sort of list. OTOH, it seems that GCC is always
11997	// conservative with the last element in structs (if it's an array), so our
11998	// current behavior is more compatible than an explicit list approach would
11999	// be.
12000	auto isFlexibleArrayMember = [&] {
12001	using FAMKind = LangOptions::StrictFlexArraysLevelKind;
12002	FAMKind StrictFlexArraysLevel =
12003	Ctx.getLangOpts().getStrictFlexArraysLevel();
12004
12005	if (Designator.isMostDerivedAnUnsizedArray())
12006	return true;
12007
12008	if (StrictFlexArraysLevel == FAMKind::Default)
12009	return true;
12010
12011	if (Designator.getMostDerivedArraySize() == 0 &&
12012	StrictFlexArraysLevel != FAMKind::IncompleteOnly)
12013	return true;
12014
12015	if (Designator.getMostDerivedArraySize() == 1 &&
12016	StrictFlexArraysLevel == FAMKind::OneZeroOrIncomplete)
12017	return true;
12018
12019	return false;
12020	};
12021
12022	return LVal.InvalidBase &&
12023	Designator.Entries.size() == Designator.MostDerivedPathLength &&
12024	Designator.MostDerivedIsArrayElement && isFlexibleArrayMember() &&
12025	isDesignatorAtObjectEnd(Ctx, LVal);
12026	}
12027
12028	/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
12029	/// Fails if the conversion would cause loss of precision.
12030	static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
12031	CharUnits &Result) {
12032	auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
12033	if (Int.ugt(RHS: CharUnitsMax))
12034	return false;
12035	Result = CharUnits::fromQuantity(Quantity: Int.getZExtValue());
12036	return true;
12037	}
12038
12039	/// If we're evaluating the object size of an instance of a struct that
12040	/// contains a flexible array member, add the size of the initializer.
12041	static void addFlexibleArrayMemberInitSize(EvalInfo &Info, const QualType &T,
12042	const LValue &LV, CharUnits &Size) {
12043	if (!T.isNull() && T->isStructureType() &&
12044	T->getAsStructureType()->getDecl()->hasFlexibleArrayMember())
12045	if (const auto *V = LV.getLValueBase().dyn_cast<const ValueDecl *>())
12046	if (const auto *VD = dyn_cast<VarDecl>(Val: V))
12047	if (VD->hasInit())
12048	Size += VD->getFlexibleArrayInitChars(Ctx: Info.Ctx);
12049	}
12050
12051	/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
12052	/// determine how many bytes exist from the beginning of the object to either
12053	/// the end of the current subobject, or the end of the object itself, depending
12054	/// on what the LValue looks like + the value of Type.
12055	///
12056	/// If this returns false, the value of Result is undefined.
12057	static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
12058	unsigned Type, const LValue &LVal,
12059	CharUnits &EndOffset) {
12060	bool DetermineForCompleteObject = refersToCompleteObject(LVal);
12061
12062	auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
12063	if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
12064	return false;
12065	return HandleSizeof(Info, Loc: ExprLoc, Type: Ty, Size&: Result);
12066	};
12067
12068	// We want to evaluate the size of the entire object. This is a valid fallback
12069	// for when Type=1 and the designator is invalid, because we're asked for an
12070	// upper-bound.
12071	if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
12072	// Type=3 wants a lower bound, so we can't fall back to this.
12073	if (Type == 3 && !DetermineForCompleteObject)
12074	return false;
12075
12076	llvm::APInt APEndOffset;
12077	if (isBaseAnAllocSizeCall(Base: LVal.getLValueBase()) &&
12078	getBytesReturnedByAllocSizeCall(Ctx: Info.Ctx, LVal, Result&: APEndOffset))
12079	return convertUnsignedAPIntToCharUnits(Int: APEndOffset, Result&: EndOffset);
12080
12081	if (LVal.InvalidBase)
12082	return false;
12083
12084	QualType BaseTy = getObjectType(B: LVal.getLValueBase());
12085	const bool Ret = CheckedHandleSizeof(BaseTy, EndOffset);
12086	addFlexibleArrayMemberInitSize(Info, T: BaseTy, LV: LVal, Size&: EndOffset);
12087	return Ret;
12088	}
12089
12090	// We want to evaluate the size of a subobject.
12091	const SubobjectDesignator &Designator = LVal.Designator;
12092
12093	// The following is a moderately common idiom in C:
12094	//
12095	// struct Foo { int a; char c[1]; };
12096	// struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
12097	// strcpy(&F->c[0], Bar);
12098	//
12099	// In order to not break too much legacy code, we need to support it.
12100	if (isUserWritingOffTheEnd(Ctx: Info.Ctx, LVal)) {
12101	// If we can resolve this to an alloc_size call, we can hand that back,
12102	// because we know for certain how many bytes there are to write to.
12103	llvm::APInt APEndOffset;
12104	if (isBaseAnAllocSizeCall(Base: LVal.getLValueBase()) &&
12105	getBytesReturnedByAllocSizeCall(Ctx: Info.Ctx, LVal, Result&: APEndOffset))
12106	return convertUnsignedAPIntToCharUnits(Int: APEndOffset, Result&: EndOffset);
12107
12108	// If we cannot determine the size of the initial allocation, then we can't
12109	// given an accurate upper-bound. However, we are still able to give
12110	// conservative lower-bounds for Type=3.
12111	if (Type == 1)
12112	return false;
12113	}
12114
12115	CharUnits BytesPerElem;
12116	if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
12117	return false;
12118
12119	// According to the GCC documentation, we want the size of the subobject
12120	// denoted by the pointer. But that's not quite right -- what we actually
12121	// want is the size of the immediately-enclosing array, if there is one.
12122	int64_t ElemsRemaining;
12123	if (Designator.MostDerivedIsArrayElement &&
12124	Designator.Entries.size() == Designator.MostDerivedPathLength) {
12125	uint64_t ArraySize = Designator.getMostDerivedArraySize();
12126	uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
12127	ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
12128	} else {
12129	ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
12130	}
12131
12132	EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
12133	return true;
12134	}
12135
12136	/// Tries to evaluate the __builtin_object_size for @p E. If successful,
12137	/// returns true and stores the result in @p Size.
12138	///
12139	/// If @p WasError is non-null, this will report whether the failure to evaluate
12140	/// is to be treated as an Error in IntExprEvaluator.
12141	static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
12142	EvalInfo &Info, uint64_t &Size) {
12143	// Determine the denoted object.
12144	LValue LVal;
12145	{
12146	// The operand of __builtin_object_size is never evaluated for side-effects.
12147	// If there are any, but we can determine the pointed-to object anyway, then
12148	// ignore the side-effects.
12149	SpeculativeEvaluationRAII SpeculativeEval(Info);
12150	IgnoreSideEffectsRAII Fold(Info);
12151
12152	if (E->isGLValue()) {
12153	// It's possible for us to be given GLValues if we're called via
12154	// Expr::tryEvaluateObjectSize.
12155	APValue RVal;
12156	if (!EvaluateAsRValue(Info, E, Result&: RVal))
12157	return false;
12158	LVal.setFrom(Ctx&: Info.Ctx, V: RVal);
12159	} else if (!EvaluatePointer(E: ignorePointerCastsAndParens(E), Result&: LVal, Info,
12160	/*InvalidBaseOK=*/true))
12161	return false;
12162	}
12163
12164	// If we point to before the start of the object, there are no accessible
12165	// bytes.
12166	if (LVal.getLValueOffset().isNegative()) {
12167	Size = 0;
12168	return true;
12169	}
12170
12171	CharUnits EndOffset;
12172	if (!determineEndOffset(Info, ExprLoc: E->getExprLoc(), Type, LVal, EndOffset))
12173	return false;
12174
12175	// If we've fallen outside of the end offset, just pretend there's nothing to
12176	// write to/read from.
12177	if (EndOffset <= LVal.getLValueOffset())
12178	Size = 0;
12179	else
12180	Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
12181	return true;
12182	}
12183
12184	bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
12185	if (!IsConstantEvaluatedBuiltinCall(E))
12186	return ExprEvaluatorBaseTy::VisitCallExpr(E);
12187	return VisitBuiltinCallExpr(E, BuiltinOp: E->getBuiltinCallee());
12188	}
12189
12190	static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
12191	APValue &Val, APSInt &Alignment) {
12192	QualType SrcTy = E->getArg(Arg: 0)->getType();
12193	if (!getAlignmentArgument(E: E->getArg(Arg: 1), ForType: SrcTy, Info, Alignment))
12194	return false;
12195	// Even though we are evaluating integer expressions we could get a pointer
12196	// argument for the __builtin_is_aligned() case.
12197	if (SrcTy->isPointerType()) {
12198	LValue Ptr;
12199	if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: Ptr, Info))
12200	return false;
12201	Ptr.moveInto(V&: Val);
12202	} else if (!SrcTy->isIntegralOrEnumerationType()) {
12203	Info.FFDiag(E: E->getArg(Arg: 0));
12204	return false;
12205	} else {
12206	APSInt SrcInt;
12207	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: SrcInt, Info))
12208	return false;
12209	assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&
12210	"Bit widths must be the same");
12211	Val = APValue(SrcInt);
12212	}
12213	assert(Val.hasValue());
12214	return true;
12215	}
12216
12217	bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
12218	unsigned BuiltinOp) {
12219	switch (BuiltinOp) {
12220	default:
12221	return false;
12222
12223	case Builtin::BI__builtin_dynamic_object_size:
12224	case Builtin::BI__builtin_object_size: {
12225	// The type was checked when we built the expression.
12226	unsigned Type =
12227	E->getArg(Arg: 1)->EvaluateKnownConstInt(Ctx: Info.Ctx).getZExtValue();
12228	assert(Type <= 3 && "unexpected type");
12229
12230	uint64_t Size;
12231	if (tryEvaluateBuiltinObjectSize(E: E->getArg(Arg: 0), Type, Info, Size))
12232	return Success(Size, E);
12233
12234	if (E->getArg(Arg: 0)->HasSideEffects(Ctx: Info.Ctx))
12235	return Success((Type & 2) ? 0 : -1, E);
12236
12237	// Expression had no side effects, but we couldn't statically determine the
12238	// size of the referenced object.
12239	switch (Info.EvalMode) {
12240	case EvalInfo::EM_ConstantExpression:
12241	case EvalInfo::EM_ConstantFold:
12242	case EvalInfo::EM_IgnoreSideEffects:
12243	// Leave it to IR generation.
12244	return Error(E);
12245	case EvalInfo::EM_ConstantExpressionUnevaluated:
12246	// Reduce it to a constant now.
12247	return Success((Type & 2) ? 0 : -1, E);
12248	}
12249
12250	llvm_unreachable("unexpected EvalMode");
12251	}
12252
12253	case Builtin::BI__builtin_os_log_format_buffer_size: {
12254	analyze_os_log::OSLogBufferLayout Layout;
12255	analyze_os_log::computeOSLogBufferLayout(Ctx&: Info.Ctx, E, layout&: Layout);
12256	return Success(Layout.size().getQuantity(), E);
12257	}
12258
12259	case Builtin::BI__builtin_is_aligned: {
12260	APValue Src;
12261	APSInt Alignment;
12262	if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
12263	return false;
12264	if (Src.isLValue()) {
12265	// If we evaluated a pointer, check the minimum known alignment.
12266	LValue Ptr;
12267	Ptr.setFrom(Ctx&: Info.Ctx, V: Src);
12268	CharUnits BaseAlignment = getBaseAlignment(Info, Value: Ptr);
12269	CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(offset: Ptr.Offset);
12270	// We can return true if the known alignment at the computed offset is
12271	// greater than the requested alignment.
12272	assert(PtrAlign.isPowerOfTwo());
12273	assert(Alignment.isPowerOf2());
12274	if (PtrAlign.getQuantity() >= Alignment)
12275	return Success(1, E);
12276	// If the alignment is not known to be sufficient, some cases could still
12277	// be aligned at run time. However, if the requested alignment is less or
12278	// equal to the base alignment and the offset is not aligned, we know that
12279	// the run-time value can never be aligned.
12280	if (BaseAlignment.getQuantity() >= Alignment &&
12281	PtrAlign.getQuantity() < Alignment)
12282	return Success(0, E);
12283	// Otherwise we can't infer whether the value is sufficiently aligned.
12284	// TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
12285	// in cases where we can't fully evaluate the pointer.
12286	Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute)
12287	<< Alignment;
12288	return false;
12289	}
12290	assert(Src.isInt());
12291	return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
12292	}
12293	case Builtin::BI__builtin_align_up: {
12294	APValue Src;
12295	APSInt Alignment;
12296	if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
12297	return false;
12298	if (!Src.isInt())
12299	return Error(E);
12300	APSInt AlignedVal =
12301	APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
12302	Src.getInt().isUnsigned());
12303	assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
12304	return Success(AlignedVal, E);
12305	}
12306	case Builtin::BI__builtin_align_down: {
12307	APValue Src;
12308	APSInt Alignment;
12309	if (!getBuiltinAlignArguments(E, Info, Val&: Src, Alignment))
12310	return false;
12311	if (!Src.isInt())
12312	return Error(E);
12313	APSInt AlignedVal =
12314	APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
12315	assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
12316	return Success(AlignedVal, E);
12317	}
12318
12319	case Builtin::BI__builtin_bitreverse8:
12320	case Builtin::BI__builtin_bitreverse16:
12321	case Builtin::BI__builtin_bitreverse32:
12322	case Builtin::BI__builtin_bitreverse64: {
12323	APSInt Val;
12324	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12325	return false;
12326
12327	return Success(Val.reverseBits(), E);
12328	}
12329
12330	case Builtin::BI__builtin_bswap16:
12331	case Builtin::BI__builtin_bswap32:
12332	case Builtin::BI__builtin_bswap64: {
12333	APSInt Val;
12334	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12335	return false;
12336
12337	return Success(Val.byteSwap(), E);
12338	}
12339
12340	case Builtin::BI__builtin_classify_type:
12341	return Success((int)EvaluateBuiltinClassifyType(E, LangOpts: Info.getLangOpts()), E);
12342
12343	case Builtin::BI__builtin_clrsb:
12344	case Builtin::BI__builtin_clrsbl:
12345	case Builtin::BI__builtin_clrsbll: {
12346	APSInt Val;
12347	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12348	return false;
12349
12350	return Success(Val.getBitWidth() - Val.getSignificantBits(), E);
12351	}
12352
12353	case Builtin::BI__builtin_clz:
12354	case Builtin::BI__builtin_clzl:
12355	case Builtin::BI__builtin_clzll:
12356	case Builtin::BI__builtin_clzs:
12357	case Builtin::BI__builtin_clzg:
12358	case Builtin::BI__lzcnt16: // Microsoft variants of count leading-zeroes
12359	case Builtin::BI__lzcnt:
12360	case Builtin::BI__lzcnt64: {
12361	APSInt Val;
12362	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12363	return false;
12364
12365	std::optional<APSInt> Fallback;
12366	if (BuiltinOp == Builtin::BI__builtin_clzg && E->getNumArgs() > 1) {
12367	APSInt FallbackTemp;
12368	if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: FallbackTemp, Info))
12369	return false;
12370	Fallback = FallbackTemp;
12371	}
12372
12373	if (!Val) {
12374	if (Fallback)
12375	return Success(*Fallback, E);
12376
12377	// When the argument is 0, the result of GCC builtins is undefined,
12378	// whereas for Microsoft intrinsics, the result is the bit-width of the
12379	// argument.
12380	bool ZeroIsUndefined = BuiltinOp != Builtin::BI__lzcnt16 &&
12381	BuiltinOp != Builtin::BI__lzcnt &&
12382	BuiltinOp != Builtin::BI__lzcnt64;
12383
12384	if (ZeroIsUndefined)
12385	return Error(E);
12386	}
12387
12388	return Success(Val.countl_zero(), E);
12389	}
12390
12391	case Builtin::BI__builtin_constant_p: {
12392	const Expr *Arg = E->getArg(Arg: 0);
12393	if (EvaluateBuiltinConstantP(Info, Arg))
12394	return Success(true, E);
12395	if (Info.InConstantContext || Arg->HasSideEffects(Ctx: Info.Ctx)) {
12396	// Outside a constant context, eagerly evaluate to false in the presence
12397	// of side-effects in order to avoid -Wunsequenced false-positives in
12398	// a branch on __builtin_constant_p(expr).
12399	return Success(false, E);
12400	}
12401	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
12402	return false;
12403	}
12404
12405	case Builtin::BI__builtin_is_constant_evaluated: {
12406	const auto *Callee = Info.CurrentCall->getCallee();
12407	if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
12408	(Info.CallStackDepth == 1 ||
12409	(Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
12410	Callee->getIdentifier() &&
12411	Callee->getIdentifier()->isStr("is_constant_evaluated")))) {
12412	// FIXME: Find a better way to avoid duplicated diagnostics.
12413	if (Info.EvalStatus.Diag)
12414	Info.report((Info.CallStackDepth == 1)
12415	? E->getExprLoc()
12416	: Info.CurrentCall->getCallRange().getBegin(),
12417	diag::warn_is_constant_evaluated_always_true_constexpr)
12418	<< (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
12419	: "std::is_constant_evaluated");
12420	}
12421
12422	return Success(Info.InConstantContext, E);
12423	}
12424
12425	case Builtin::BI__builtin_ctz:
12426	case Builtin::BI__builtin_ctzl:
12427	case Builtin::BI__builtin_ctzll:
12428	case Builtin::BI__builtin_ctzs:
12429	case Builtin::BI__builtin_ctzg: {
12430	APSInt Val;
12431	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12432	return false;
12433
12434	std::optional<APSInt> Fallback;
12435	if (BuiltinOp == Builtin::BI__builtin_ctzg && E->getNumArgs() > 1) {
12436	APSInt FallbackTemp;
12437	if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: FallbackTemp, Info))
12438	return false;
12439	Fallback = FallbackTemp;
12440	}
12441
12442	if (!Val) {
12443	if (Fallback)
12444	return Success(*Fallback, E);
12445
12446	return Error(E);
12447	}
12448
12449	return Success(Val.countr_zero(), E);
12450	}
12451
12452	case Builtin::BI__builtin_eh_return_data_regno: {
12453	int Operand = E->getArg(Arg: 0)->EvaluateKnownConstInt(Ctx: Info.Ctx).getZExtValue();
12454	Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(RegNo: Operand);
12455	return Success(Operand, E);
12456	}
12457
12458	case Builtin::BI__builtin_expect:
12459	case Builtin::BI__builtin_expect_with_probability:
12460	return Visit(E->getArg(Arg: 0));
12461
12462	case Builtin::BI__builtin_ffs:
12463	case Builtin::BI__builtin_ffsl:
12464	case Builtin::BI__builtin_ffsll: {
12465	APSInt Val;
12466	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12467	return false;
12468
12469	unsigned N = Val.countr_zero();
12470	return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
12471	}
12472
12473	case Builtin::BI__builtin_fpclassify: {
12474	APFloat Val(0.0);
12475	if (!EvaluateFloat(E: E->getArg(Arg: 5), Result&: Val, Info))
12476	return false;
12477	unsigned Arg;
12478	switch (Val.getCategory()) {
12479	case APFloat::fcNaN: Arg = 0; break;
12480	case APFloat::fcInfinity: Arg = 1; break;
12481	case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
12482	case APFloat::fcZero: Arg = 4; break;
12483	}
12484	return Visit(E->getArg(Arg));
12485	}
12486
12487	case Builtin::BI__builtin_isinf_sign: {
12488	APFloat Val(0.0);
12489	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12490	Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
12491	}
12492
12493	case Builtin::BI__builtin_isinf: {
12494	APFloat Val(0.0);
12495	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12496	Success(Val.isInfinity() ? 1 : 0, E);
12497	}
12498
12499	case Builtin::BI__builtin_isfinite: {
12500	APFloat Val(0.0);
12501	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12502	Success(Val.isFinite() ? 1 : 0, E);
12503	}
12504
12505	case Builtin::BI__builtin_isnan: {
12506	APFloat Val(0.0);
12507	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12508	Success(Val.isNaN() ? 1 : 0, E);
12509	}
12510
12511	case Builtin::BI__builtin_isnormal: {
12512	APFloat Val(0.0);
12513	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12514	Success(Val.isNormal() ? 1 : 0, E);
12515	}
12516
12517	case Builtin::BI__builtin_issubnormal: {
12518	APFloat Val(0.0);
12519	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12520	Success(Val.isDenormal() ? 1 : 0, E);
12521	}
12522
12523	case Builtin::BI__builtin_iszero: {
12524	APFloat Val(0.0);
12525	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12526	Success(Val.isZero() ? 1 : 0, E);
12527	}
12528
12529	case Builtin::BI__builtin_issignaling: {
12530	APFloat Val(0.0);
12531	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12532	Success(Val.isSignaling() ? 1 : 0, E);
12533	}
12534
12535	case Builtin::BI__builtin_isfpclass: {
12536	APSInt MaskVal;
12537	if (!EvaluateInteger(E: E->getArg(Arg: 1), Result&: MaskVal, Info))
12538	return false;
12539	unsigned Test = static_cast<llvm::FPClassTest>(MaskVal.getZExtValue());
12540	APFloat Val(0.0);
12541	return EvaluateFloat(E: E->getArg(Arg: 0), Result&: Val, Info) &&
12542	Success((Val.classify() & Test) ? 1 : 0, E);
12543	}
12544
12545	case Builtin::BI__builtin_parity:
12546	case Builtin::BI__builtin_parityl:
12547	case Builtin::BI__builtin_parityll: {
12548	APSInt Val;
12549	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12550	return false;
12551
12552	return Success(Val.popcount() % 2, E);
12553	}
12554
12555	case Builtin::BI__builtin_popcount:
12556	case Builtin::BI__builtin_popcountl:
12557	case Builtin::BI__builtin_popcountll:
12558	case Builtin::BI__builtin_popcountg:
12559	case Builtin::BI__popcnt16: // Microsoft variants of popcount
12560	case Builtin::BI__popcnt:
12561	case Builtin::BI__popcnt64: {
12562	APSInt Val;
12563	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info))
12564	return false;
12565
12566	return Success(Val.popcount(), E);
12567	}
12568
12569	case Builtin::BI__builtin_rotateleft8:
12570	case Builtin::BI__builtin_rotateleft16:
12571	case Builtin::BI__builtin_rotateleft32:
12572	case Builtin::BI__builtin_rotateleft64:
12573	case Builtin::BI_rotl8: // Microsoft variants of rotate right
12574	case Builtin::BI_rotl16:
12575	case Builtin::BI_rotl:
12576	case Builtin::BI_lrotl:
12577	case Builtin::BI_rotl64: {
12578	APSInt Val, Amt;
12579	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
12580	!EvaluateInteger(E: E->getArg(Arg: 1), Result&: Amt, Info))
12581	return false;
12582
12583	return Success(Val.rotl(rotateAmt: Amt.urem(RHS: Val.getBitWidth())), E);
12584	}
12585
12586	case Builtin::BI__builtin_rotateright8:
12587	case Builtin::BI__builtin_rotateright16:
12588	case Builtin::BI__builtin_rotateright32:
12589	case Builtin::BI__builtin_rotateright64:
12590	case Builtin::BI_rotr8: // Microsoft variants of rotate right
12591	case Builtin::BI_rotr16:
12592	case Builtin::BI_rotr:
12593	case Builtin::BI_lrotr:
12594	case Builtin::BI_rotr64: {
12595	APSInt Val, Amt;
12596	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: Val, Info) ||
12597	!EvaluateInteger(E: E->getArg(Arg: 1), Result&: Amt, Info))
12598	return false;
12599
12600	return Success(Val.rotr(rotateAmt: Amt.urem(RHS: Val.getBitWidth())), E);
12601	}
12602
12603	case Builtin::BIstrlen:
12604	case Builtin::BIwcslen:
12605	// A call to strlen is not a constant expression.
12606	if (Info.getLangOpts().CPlusPlus11)
12607	Info.CCEDiag(E, diag::note_constexpr_invalid_function)
12608	<< /*isConstexpr*/ 0 << /*isConstructor*/ 0
12609	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
12610	else
12611	Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
12612	[[fallthrough]];
12613	case Builtin::BI__builtin_strlen:
12614	case Builtin::BI__builtin_wcslen: {
12615	// As an extension, we support __builtin_strlen() as a constant expression,
12616	// and support folding strlen() to a constant.
12617	uint64_t StrLen;
12618	if (EvaluateBuiltinStrLen(E: E->getArg(Arg: 0), Result&: StrLen, Info))
12619	return Success(StrLen, E);
12620	return false;
12621	}
12622
12623	case Builtin::BIstrcmp:
12624	case Builtin::BIwcscmp:
12625	case Builtin::BIstrncmp:
12626	case Builtin::BIwcsncmp:
12627	case Builtin::BImemcmp:
12628	case Builtin::BIbcmp:
12629	case Builtin::BIwmemcmp:
12630	// A call to strlen is not a constant expression.
12631	if (Info.getLangOpts().CPlusPlus11)
12632	Info.CCEDiag(E, diag::note_constexpr_invalid_function)
12633	<< /*isConstexpr*/ 0 << /*isConstructor*/ 0
12634	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str();
12635	else
12636	Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
12637	[[fallthrough]];
12638	case Builtin::BI__builtin_strcmp:
12639	case Builtin::BI__builtin_wcscmp:
12640	case Builtin::BI__builtin_strncmp:
12641	case Builtin::BI__builtin_wcsncmp:
12642	case Builtin::BI__builtin_memcmp:
12643	case Builtin::BI__builtin_bcmp:
12644	case Builtin::BI__builtin_wmemcmp: {
12645	LValue String1, String2;
12646	if (!EvaluatePointer(E: E->getArg(Arg: 0), Result&: String1, Info) ||
12647	!EvaluatePointer(E: E->getArg(Arg: 1), Result&: String2, Info))
12648	return false;
12649
12650	uint64_t MaxLength = uint64_t(-1);
12651	if (BuiltinOp != Builtin::BIstrcmp &&
12652	BuiltinOp != Builtin::BIwcscmp &&
12653	BuiltinOp != Builtin::BI__builtin_strcmp &&
12654	BuiltinOp != Builtin::BI__builtin_wcscmp) {
12655	APSInt N;
12656	if (!EvaluateInteger(E: E->getArg(Arg: 2), Result&: N, Info))
12657	return false;
12658	MaxLength = N.getZExtValue();
12659	}
12660
12661	// Empty substrings compare equal by definition.
12662	if (MaxLength == 0u)
12663	return Success(0, E);
12664
12665	if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
12666	!String2.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
12667	String1.Designator.Invalid || String2.Designator.Invalid)
12668	return false;
12669
12670	QualType CharTy1 = String1.Designator.getType(Info.Ctx);
12671	QualType CharTy2 = String2.Designator.getType(Info.Ctx);
12672
12673	bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
12674	BuiltinOp == Builtin::BIbcmp ||
12675	BuiltinOp == Builtin::BI__builtin_memcmp ||
12676	BuiltinOp == Builtin::BI__builtin_bcmp;
12677
12678	assert(IsRawByte ||
12679	(Info.Ctx.hasSameUnqualifiedType(
12680	CharTy1, E->getArg(0)->getType()->getPointeeType()) &&
12681	Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)));
12682
12683	// For memcmp, allow comparing any arrays of '[[un]signed] char' or
12684	// 'char8_t', but no other types.
12685	if (IsRawByte &&
12686	!(isOneByteCharacterType(T: CharTy1) && isOneByteCharacterType(T: CharTy2))) {
12687	// FIXME: Consider using our bit_cast implementation to support this.
12688	Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
12689	<< ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str()
12690	<< CharTy1 << CharTy2;
12691	return false;
12692	}
12693
12694	const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
12695	return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) &&
12696	handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) &&
12697	Char1.isInt() && Char2.isInt();
12698	};
12699	const auto &AdvanceElems = [&] {
12700	return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) &&
12701	HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1);
12702	};
12703
12704	bool StopAtNull =
12705	(BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
12706	BuiltinOp != Builtin::BIwmemcmp &&
12707	BuiltinOp != Builtin::BI__builtin_memcmp &&
12708	BuiltinOp != Builtin::BI__builtin_bcmp &&
12709	BuiltinOp != Builtin::BI__builtin_wmemcmp);
12710	bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
12711	BuiltinOp == Builtin::BIwcsncmp ||
12712	BuiltinOp == Builtin::BIwmemcmp ||
12713	BuiltinOp == Builtin::BI__builtin_wcscmp ||
12714	BuiltinOp == Builtin::BI__builtin_wcsncmp ||
12715	BuiltinOp == Builtin::BI__builtin_wmemcmp;
12716
12717	for (; MaxLength; --MaxLength) {
12718	APValue Char1, Char2;
12719	if (!ReadCurElems(Char1, Char2))
12720	return false;
12721	if (Char1.getInt().ne(RHS: Char2.getInt())) {
12722	if (IsWide) // wmemcmp compares with wchar_t signedness.
12723	return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
12724	// memcmp always compares unsigned chars.
12725	return Success(Char1.getInt().ult(RHS: Char2.getInt()) ? -1 : 1, E);
12726	}
12727	if (StopAtNull && !Char1.getInt())
12728	return Success(0, E);
12729	assert(!(StopAtNull && !Char2.getInt()));
12730	if (!AdvanceElems())
12731	return false;
12732	}
12733	// We hit the strncmp / memcmp limit.
12734	return Success(0, E);
12735	}
12736
12737	case Builtin::BI__atomic_always_lock_free:
12738	case Builtin::BI__atomic_is_lock_free:
12739	case Builtin::BI__c11_atomic_is_lock_free: {
12740	APSInt SizeVal;
12741	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: SizeVal, Info))
12742	return false;
12743
12744	// For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
12745	// of two less than or equal to the maximum inline atomic width, we know it
12746	// is lock-free. If the size isn't a power of two, or greater than the
12747	// maximum alignment where we promote atomics, we know it is not lock-free
12748	// (at least not in the sense of atomic_is_lock_free). Otherwise,
12749	// the answer can only be determined at runtime; for example, 16-byte
12750	// atomics have lock-free implementations on some, but not all,
12751	// x86-64 processors.
12752
12753	// Check power-of-two.
12754	CharUnits Size = CharUnits::fromQuantity(Quantity: SizeVal.getZExtValue());
12755	if (Size.isPowerOfTwo()) {
12756	// Check against inlining width.
12757	unsigned InlineWidthBits =
12758	Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
12759	if (Size <= Info.Ctx.toCharUnitsFromBits(BitSize: InlineWidthBits)) {
12760	if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
12761	Size == CharUnits::One() ||
12762	E->getArg(1)->isNullPointerConstant(Info.Ctx,
12763	Expr::NPC_NeverValueDependent))
12764	// OK, we will inline appropriately-aligned operations of this size,
12765	// and _Atomic(T) is appropriately-aligned.
12766	return Success(1, E);
12767
12768	QualType PointeeType = E->getArg(Arg: 1)->IgnoreImpCasts()->getType()->
12769	castAs<PointerType>()->getPointeeType();
12770	if (!PointeeType->isIncompleteType() &&
12771	Info.Ctx.getTypeAlignInChars(T: PointeeType) >= Size) {
12772	// OK, we will inline operations on this object.
12773	return Success(1, E);
12774	}
12775	}
12776	}
12777
12778	return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
12779	Success(0, E) : Error(E);
12780	}
12781	case Builtin::BI__builtin_addcb:
12782	case Builtin::BI__builtin_addcs:
12783	case Builtin::BI__builtin_addc:
12784	case Builtin::BI__builtin_addcl:
12785	case Builtin::BI__builtin_addcll:
12786	case Builtin::BI__builtin_subcb:
12787	case Builtin::BI__builtin_subcs:
12788	case Builtin::BI__builtin_subc:
12789	case Builtin::BI__builtin_subcl:
12790	case Builtin::BI__builtin_subcll: {
12791	LValue CarryOutLValue;
12792	APSInt LHS, RHS, CarryIn, CarryOut, Result;
12793	QualType ResultType = E->getArg(Arg: 0)->getType();
12794	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
12795	!EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info) ||
12796	!EvaluateInteger(E: E->getArg(Arg: 2), Result&: CarryIn, Info) ||
12797	!EvaluatePointer(E: E->getArg(Arg: 3), Result&: CarryOutLValue, Info))
12798	return false;
12799	// Copy the number of bits and sign.
12800	Result = LHS;
12801	CarryOut = LHS;
12802
12803	bool FirstOverflowed = false;
12804	bool SecondOverflowed = false;
12805	switch (BuiltinOp) {
12806	default:
12807	llvm_unreachable("Invalid value for BuiltinOp");
12808	case Builtin::BI__builtin_addcb:
12809	case Builtin::BI__builtin_addcs:
12810	case Builtin::BI__builtin_addc:
12811	case Builtin::BI__builtin_addcl:
12812	case Builtin::BI__builtin_addcll:
12813	Result =
12814	LHS.uadd_ov(RHS, Overflow&: FirstOverflowed).uadd_ov(RHS: CarryIn, Overflow&: SecondOverflowed);
12815	break;
12816	case Builtin::BI__builtin_subcb:
12817	case Builtin::BI__builtin_subcs:
12818	case Builtin::BI__builtin_subc:
12819	case Builtin::BI__builtin_subcl:
12820	case Builtin::BI__builtin_subcll:
12821	Result =
12822	LHS.usub_ov(RHS, Overflow&: FirstOverflowed).usub_ov(RHS: CarryIn, Overflow&: SecondOverflowed);
12823	break;
12824	}
12825
12826	// It is possible for both overflows to happen but CGBuiltin uses an OR so
12827	// this is consistent.
12828	CarryOut = (uint64_t)(FirstOverflowed | SecondOverflowed);
12829	APValue APV{CarryOut};
12830	if (!handleAssignment(Info, E, CarryOutLValue, ResultType, APV))
12831	return false;
12832	return Success(Result, E);
12833	}
12834	case Builtin::BI__builtin_add_overflow:
12835	case Builtin::BI__builtin_sub_overflow:
12836	case Builtin::BI__builtin_mul_overflow:
12837	case Builtin::BI__builtin_sadd_overflow:
12838	case Builtin::BI__builtin_uadd_overflow:
12839	case Builtin::BI__builtin_uaddl_overflow:
12840	case Builtin::BI__builtin_uaddll_overflow:
12841	case Builtin::BI__builtin_usub_overflow:
12842	case Builtin::BI__builtin_usubl_overflow:
12843	case Builtin::BI__builtin_usubll_overflow:
12844	case Builtin::BI__builtin_umul_overflow:
12845	case Builtin::BI__builtin_umull_overflow:
12846	case Builtin::BI__builtin_umulll_overflow:
12847	case Builtin::BI__builtin_saddl_overflow:
12848	case Builtin::BI__builtin_saddll_overflow:
12849	case Builtin::BI__builtin_ssub_overflow:
12850	case Builtin::BI__builtin_ssubl_overflow:
12851	case Builtin::BI__builtin_ssubll_overflow:
12852	case Builtin::BI__builtin_smul_overflow:
12853	case Builtin::BI__builtin_smull_overflow:
12854	case Builtin::BI__builtin_smulll_overflow: {
12855	LValue ResultLValue;
12856	APSInt LHS, RHS;
12857
12858	QualType ResultType = E->getArg(Arg: 2)->getType()->getPointeeType();
12859	if (!EvaluateInteger(E: E->getArg(Arg: 0), Result&: LHS, Info) ||
12860	!EvaluateInteger(E: E->getArg(Arg: 1), Result&: RHS, Info) ||
12861	!EvaluatePointer(E: E->getArg(Arg: 2), Result&: ResultLValue, Info))
12862	return false;
12863
12864	APSInt Result;
12865	bool DidOverflow = false;
12866
12867	// If the types don't have to match, enlarge all 3 to the largest of them.
12868	if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12869	BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12870	BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12871	bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
12872	ResultType->isSignedIntegerOrEnumerationType();
12873	bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
12874	ResultType->isSignedIntegerOrEnumerationType();
12875	uint64_t LHSSize = LHS.getBitWidth();
12876	uint64_t RHSSize = RHS.getBitWidth();
12877	uint64_t ResultSize = Info.Ctx.getTypeSize(T: ResultType);
12878	uint64_t MaxBits = std::max(a: std::max(a: LHSSize, b: RHSSize), b: ResultSize);
12879
12880	// Add an additional bit if the signedness isn't uniformly agreed to. We
12881	// could do this ONLY if there is a signed and an unsigned that both have
12882	// MaxBits, but the code to check that is pretty nasty. The issue will be
12883	// caught in the shrink-to-result later anyway.
12884	if (IsSigned && !AllSigned)
12885	++MaxBits;
12886
12887	LHS = APSInt(LHS.extOrTrunc(width: MaxBits), !IsSigned);
12888	RHS = APSInt(RHS.extOrTrunc(width: MaxBits), !IsSigned);
12889	Result = APSInt(MaxBits, !IsSigned);
12890	}
12891
12892	// Find largest int.
12893	switch (BuiltinOp) {
12894	default:
12895	llvm_unreachable("Invalid value for BuiltinOp");
12896	case Builtin::BI__builtin_add_overflow:
12897	case Builtin::BI__builtin_sadd_overflow:
12898	case Builtin::BI__builtin_saddl_overflow:
12899	case Builtin::BI__builtin_saddll_overflow:
12900	case Builtin::BI__builtin_uadd_overflow:
12901	case Builtin::BI__builtin_uaddl_overflow:
12902	case Builtin::BI__builtin_uaddll_overflow:
12903	Result = LHS.isSigned() ? LHS.sadd_ov(RHS, Overflow&: DidOverflow)
12904	: LHS.uadd_ov(RHS, Overflow&: DidOverflow);
12905	break;
12906	case Builtin::BI__builtin_sub_overflow:
12907	case Builtin::BI__builtin_ssub_overflow:
12908	case Builtin::BI__builtin_ssubl_overflow:
12909	case Builtin::BI__builtin_ssubll_overflow:
12910	case Builtin::BI__builtin_usub_overflow:
12911	case Builtin::BI__builtin_usubl_overflow:
12912	case Builtin::BI__builtin_usubll_overflow:
12913	Result = LHS.isSigned() ? LHS.ssub_ov(RHS, Overflow&: DidOverflow)
12914	: LHS.usub_ov(RHS, Overflow&: DidOverflow);
12915	break;
12916	case Builtin::BI__builtin_mul_overflow:
12917	case Builtin::BI__builtin_smul_overflow:
12918	case Builtin::BI__builtin_smull_overflow:
12919	case Builtin::BI__builtin_smulll_overflow:
12920	case Builtin::BI__builtin_umul_overflow:
12921	case Builtin::BI__builtin_umull_overflow:
12922	case Builtin::BI__builtin_umulll_overflow:
12923	Result = LHS.isSigned() ? LHS.smul_ov(RHS, Overflow&: DidOverflow)
12924	: LHS.umul_ov(RHS, Overflow&: DidOverflow);
12925	break;
12926	}
12927
12928	// In the case where multiple sizes are allowed, truncate and see if
12929	// the values are the same.
12930	if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12931	BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12932	BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12933	// APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
12934	// since it will give us the behavior of a TruncOrSelf in the case where
12935	// its parameter <= its size. We previously set Result to be at least the
12936	// type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
12937	// will work exactly like TruncOrSelf.
12938	APSInt Temp = Result.extOrTrunc(width: Info.Ctx.getTypeSize(T: ResultType));
12939	Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());
12940
12941	if (!APSInt::isSameValue(I1: Temp, I2: Result))
12942	DidOverflow = true;
12943	Result = Temp;
12944	}
12945
12946	APValue APV{Result};
12947	if (!handleAssignment(Info, E, ResultLValue, ResultType, APV))
12948	return false;
12949	return Success(DidOverflow, E);
12950	}
12951	}
12952	}
12953
12954	/// Determine whether this is a pointer past the end of the complete
12955	/// object referred to by the lvalue.
12956	static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
12957	const LValue &LV) {
12958	// A null pointer can be viewed as being "past the end" but we don't
12959	// choose to look at it that way here.
12960	if (!LV.getLValueBase())
12961	return false;
12962
12963	// If the designator is valid and refers to a subobject, we're not pointing
12964	// past the end.
12965	if (!LV.getLValueDesignator().Invalid &&
12966	!LV.getLValueDesignator().isOnePastTheEnd())
12967	return false;
12968
12969	// A pointer to an incomplete type might be past-the-end if the type's size is
12970	// zero. We cannot tell because the type is incomplete.
12971	QualType Ty = getType(B: LV.getLValueBase());
12972	if (Ty->isIncompleteType())
12973	return true;
12974
12975	// Can't be past the end of an invalid object.
12976	if (LV.getLValueDesignator().Invalid)
12977	return false;
12978
12979	// We're a past-the-end pointer if we point to the byte after the object,
12980	// no matter what our type or path is.
12981	auto Size = Ctx.getTypeSizeInChars(T: Ty);
12982	return LV.getLValueOffset() == Size;
12983	}
12984
12985	namespace {
12986
12987	/// Data recursive integer evaluator of certain binary operators.
12988	///
12989	/// We use a data recursive algorithm for binary operators so that we are able
12990	/// to handle extreme cases of chained binary operators without causing stack
12991	/// overflow.
12992	class DataRecursiveIntBinOpEvaluator {
12993	struct EvalResult {
12994	APValue Val;
12995	bool Failed = false;
12996
12997	EvalResult() = default;
12998
12999	void swap(EvalResult &RHS) {
13000	Val.swap(RHS&: RHS.Val);
13001	Failed = RHS.Failed;
13002	RHS.Failed = false;
13003	}
13004	};
13005
13006	struct Job {
13007	const Expr *E;
13008	EvalResult LHSResult; // meaningful only for binary operator expression.
13009	enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
13010
13011	Job() = default;
13012	Job(Job &&) = default;
13013
13014	void startSpeculativeEval(EvalInfo &Info) {
13015	SpecEvalRAII = SpeculativeEvaluationRAII(Info);
13016	}
13017
13018	private:
13019	SpeculativeEvaluationRAII SpecEvalRAII;
13020	};
13021
13022	SmallVector<Job, 16> Queue;
13023
13024	IntExprEvaluator &IntEval;
13025	EvalInfo &Info;
13026	APValue &FinalResult;
13027
13028	public:
13029	DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
13030	: IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
13031
13032	/// True if \param E is a binary operator that we are going to handle
13033	/// data recursively.
13034	/// We handle binary operators that are comma, logical, or that have operands
13035	/// with integral or enumeration type.
13036	static bool shouldEnqueue(const BinaryOperator *E) {
13037	return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
13038	(E->isPRValue() && E->getType()->isIntegralOrEnumerationType() &&
13039	E->getLHS()->getType()->isIntegralOrEnumerationType() &&
13040	E->getRHS()->getType()->isIntegralOrEnumerationType());
13041	}
13042
13043	bool Traverse(const BinaryOperator *E) {
13044	enqueue(E);
13045	EvalResult PrevResult;
13046	while (!Queue.empty())
13047	process(Result&: PrevResult);
13048
13049	if (PrevResult.Failed) return false;
13050
13051	FinalResult.swap(RHS&: PrevResult.Val);
13052	return true;
13053	}
13054
13055	private:
13056	bool Success(uint64_t Value, const Expr *E, APValue &Result) {
13057	return IntEval.Success(Value, E, Result);
13058	}
13059	bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
13060	return IntEval.Success(SI: Value, E, Result);
13061	}
13062	bool Error(const Expr *E) {
13063	return IntEval.Error(E);
13064	}
13065	bool Error(const Expr *E, diag::kind D) {
13066	return IntEval.Error(E, D);
13067	}
13068
13069	OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
13070	return Info.CCEDiag(E, DiagId: D);
13071	}
13072
13073	// Returns true if visiting the RHS is necessary, false otherwise.
13074	bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
13075	bool &SuppressRHSDiags);
13076
13077	bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
13078	const BinaryOperator *E, APValue &Result);
13079
13080	void EvaluateExpr(const Expr *E, EvalResult &Result) {
13081	Result.Failed = !Evaluate(Result&: Result.Val, Info, E);
13082	if (Result.Failed)
13083	Result.Val = APValue();
13084	}
13085
13086	void process(EvalResult &Result);
13087
13088	void enqueue(const Expr *E) {
13089	E = E->IgnoreParens();
13090	Queue.resize(N: Queue.size()+1);
13091	Queue.back().E = E;
13092	Queue.back().Kind = Job::AnyExprKind;
13093	}
13094	};
13095
13096	}
13097
13098	bool DataRecursiveIntBinOpEvaluator::
13099	VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
13100	bool &SuppressRHSDiags) {
13101	if (E->getOpcode() == BO_Comma) {
13102	// Ignore LHS but note if we could not evaluate it.
13103	if (LHSResult.Failed)
13104	return Info.noteSideEffect();
13105	return true;
13106	}
13107
13108	if (E->isLogicalOp()) {
13109	bool LHSAsBool;
13110	if (!LHSResult.Failed && HandleConversionToBool(Val: LHSResult.Val, Result&: LHSAsBool)) {
13111	// We were able to evaluate the LHS, see if we can get away with not
13112	// evaluating the RHS: 0 && X -> 0, 1 || X -> 1
13113	if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
13114	Success(LHSAsBool, E, LHSResult.Val);
13115	return false; // Ignore RHS
13116	}
13117	} else {
13118	LHSResult.Failed = true;
13119
13120	// Since we weren't able to evaluate the left hand side, it
13121	// might have had side effects.
13122	if (!Info.noteSideEffect())
13123	return false;
13124
13125	// We can't evaluate the LHS; however, sometimes the result
13126	// is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
13127	// Don't ignore RHS and suppress diagnostics from this arm.
13128	SuppressRHSDiags = true;
13129	}
13130
13131	return true;
13132	}
13133
13134	assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
13135	E->getRHS()->getType()->isIntegralOrEnumerationType());
13136
13137	if (LHSResult.Failed && !Info.noteFailure())
13138	return false; // Ignore RHS;
13139
13140	return true;
13141	}
13142
13143	static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
13144	bool IsSub) {
13145	// Compute the new offset in the appropriate width, wrapping at 64 bits.
13146	// FIXME: When compiling for a 32-bit target, we should use 32-bit
13147	// offsets.
13148	assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
13149	CharUnits &Offset = LVal.getLValueOffset();
13150	uint64_t Offset64 = Offset.getQuantity();
13151	uint64_t Index64 = Index.extOrTrunc(width: 64).getZExtValue();
13152	Offset = CharUnits::fromQuantity(Quantity: IsSub ? Offset64 - Index64
13153	: Offset64 + Index64);
13154	}
13155
13156	bool DataRecursiveIntBinOpEvaluator::
13157	VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
13158	const BinaryOperator *E, APValue &Result) {
13159	if (E->getOpcode() == BO_Comma) {
13160	if (RHSResult.Failed)
13161	return false;
13162	Result = RHSResult.Val;
13163	return true;
13164	}
13165
13166	if (E->isLogicalOp()) {
13167	bool lhsResult, rhsResult;
13168	bool LHSIsOK = HandleConversionToBool(Val: LHSResult.Val, Result&: lhsResult);
13169	bool RHSIsOK = HandleConversionToBool(Val: RHSResult.Val, Result&: rhsResult);
13170
13171	if (LHSIsOK) {
13172	if (RHSIsOK) {
13173	if (E->getOpcode() == BO_LOr)
13174	return Success(lhsResult || rhsResult, E, Result);
13175	else
13176	return Success(lhsResult && rhsResult, E, Result);
13177	}
13178	} else {
13179	if (RHSIsOK) {
13180	// We can't evaluate the LHS; however, sometimes the result
13181	// is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
13182	if (rhsResult == (E->getOpcode() == BO_LOr))
13183	return Success(rhsResult, E, Result);
13184	}
13185	}
13186
13187	return false;
13188	}
13189
13190	assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
13191	E->getRHS()->getType()->isIntegralOrEnumerationType());
13192
13193	if (LHSResult.Failed || RHSResult.Failed)
13194	return false;
13195
13196	const APValue &LHSVal = LHSResult.Val;
13197	const APValue &RHSVal = RHSResult.Val;
13198
13199	// Handle cases like (unsigned long)&a + 4.
13200	if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
13201	Result = LHSVal;
13202	addOrSubLValueAsInteger(LVal&: Result, Index: RHSVal.getInt(), IsSub: E->getOpcode() == BO_Sub);
13203	return true;
13204	}
13205
13206	// Handle cases like 4 + (unsigned long)&a
13207	if (E->getOpcode() == BO_Add &&
13208	RHSVal.isLValue() && LHSVal.isInt()) {
13209	Result = RHSVal;
13210	addOrSubLValueAsInteger(LVal&: Result, Index: LHSVal.getInt(), /*IsSub*/false);
13211	return true;
13212	}
13213
13214	if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
13215	// Handle (intptr_t)&&A - (intptr_t)&&B.
13216	if (!LHSVal.getLValueOffset().isZero() ||
13217	!RHSVal.getLValueOffset().isZero())
13218	return false;
13219	const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
13220	const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
13221	if (!LHSExpr || !RHSExpr)
13222	return false;
13223	const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: LHSExpr);
13224	const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: RHSExpr);
13225	if (!LHSAddrExpr || !RHSAddrExpr)
13226	return false;
13227	// Make sure both labels come from the same function.
13228	if (LHSAddrExpr->getLabel()->getDeclContext() !=
13229	RHSAddrExpr->getLabel()->getDeclContext())
13230	return false;
13231	Result = APValue(LHSAddrExpr, RHSAddrExpr);
13232	return true;
13233	}
13234
13235	// All the remaining cases expect both operands to be an integer
13236	if (!LHSVal.isInt() || !RHSVal.isInt())
13237	return Error(E);
13238
13239	// Set up the width and signedness manually, in case it can't be deduced
13240	// from the operation we're performing.
13241	// FIXME: Don't do this in the cases where we can deduce it.
13242	APSInt Value(Info.Ctx.getIntWidth(T: E->getType()),
13243	E->getType()->isUnsignedIntegerOrEnumerationType());
13244	if (!handleIntIntBinOp(Info, E, LHS: LHSVal.getInt(), Opcode: E->getOpcode(),
13245	RHS: RHSVal.getInt(), Result&: Value))
13246	return false;
13247	return Success(Value, E, Result);
13248	}
13249
13250	void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
13251	Job &job = Queue.back();
13252
13253	switch (job.Kind) {
13254	case Job::AnyExprKind: {
13255	if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(Val: job.E)) {
13256	if (shouldEnqueue(E: Bop)) {
13257	job.Kind = Job::BinOpKind;
13258	enqueue(E: Bop->getLHS());
13259	return;
13260	}
13261	}
13262
13263	EvaluateExpr(E: job.E, Result);
13264	Queue.pop_back();
13265	return;
13266	}
13267
13268	case Job::BinOpKind: {
13269	const BinaryOperator *Bop = cast<BinaryOperator>(Val: job.E);
13270	bool SuppressRHSDiags = false;
13271	if (!VisitBinOpLHSOnly(LHSResult&: Result, E: Bop, SuppressRHSDiags)) {
13272	Queue.pop_back();
13273	return;
13274	}
13275	if (SuppressRHSDiags)
13276	job.startSpeculativeEval(Info);
13277	job.LHSResult.swap(RHS&: Result);
13278	job.Kind = Job::BinOpVisitedLHSKind;
13279	enqueue(E: Bop->getRHS());
13280	return;
13281	}
13282
13283	case Job::BinOpVisitedLHSKind: {
13284	const BinaryOperator *Bop = cast<BinaryOperator>(Val: job.E);
13285	EvalResult RHS;
13286	RHS.swap(RHS&: Result);
13287	Result.Failed = !VisitBinOp(LHSResult: job.LHSResult, RHSResult: RHS, E: Bop, Result&: Result.Val);
13288	Queue.pop_back();
13289	return;
13290	}
13291	}
13292
13293	llvm_unreachable("Invalid Job::Kind!");
13294	}
13295
13296	namespace {
13297	enum class CmpResult {
13298	Unequal,
13299	Less,
13300	Equal,
13301	Greater,
13302	Unordered,
13303	};
13304	}
13305
13306	template <class SuccessCB, class AfterCB>
13307	static bool
13308	EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
13309	SuccessCB &&Success, AfterCB &&DoAfter) {
13310	assert(!E->isValueDependent());
13311	assert(E->isComparisonOp() && "expected comparison operator");
13312	assert((E->getOpcode() == BO_Cmp ||
13313	E->getType()->isIntegralOrEnumerationType()) &&
13314	"unsupported binary expression evaluation");
13315	auto Error = [&](const Expr *E) {
13316	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
13317	return false;
13318	};
13319
13320	bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
13321	bool IsEquality = E->isEqualityOp();
13322
13323	QualType LHSTy = E->getLHS()->getType();
13324	QualType RHSTy = E->getRHS()->getType();
13325
13326	if (LHSTy->isIntegralOrEnumerationType() &&
13327	RHSTy->isIntegralOrEnumerationType()) {
13328	APSInt LHS, RHS;
13329	bool LHSOK = EvaluateInteger(E: E->getLHS(), Result&: LHS, Info);
13330	if (!LHSOK && !Info.noteFailure())
13331	return false;
13332	if (!EvaluateInteger(E: E->getRHS(), Result&: RHS, Info) || !LHSOK)
13333	return false;
13334	if (LHS < RHS)
13335	return Success(CmpResult::Less, E);
13336	if (LHS > RHS)
13337	return Success(CmpResult::Greater, E);
13338	return Success(CmpResult::Equal, E);
13339	}
13340
13341	if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
13342	APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(Ty: LHSTy));
13343	APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(Ty: RHSTy));
13344
13345	bool LHSOK = EvaluateFixedPointOrInteger(E: E->getLHS(), Result&: LHSFX, Info);
13346	if (!LHSOK && !Info.noteFailure())
13347	return false;
13348	if (!EvaluateFixedPointOrInteger(E: E->getRHS(), Result&: RHSFX, Info) || !LHSOK)
13349	return false;
13350	if (LHSFX < RHSFX)
13351	return Success(CmpResult::Less, E);
13352	if (LHSFX > RHSFX)
13353	return Success(CmpResult::Greater, E);
13354	return Success(CmpResult::Equal, E);
13355	}
13356
13357	if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
13358	ComplexValue LHS, RHS;
13359	bool LHSOK;
13360	if (E->isAssignmentOp()) {
13361	LValue LV;
13362	EvaluateLValue(E: E->getLHS(), Result&: LV, Info);
13363	LHSOK = false;
13364	} else if (LHSTy->isRealFloatingType()) {
13365	LHSOK = EvaluateFloat(E: E->getLHS(), Result&: LHS.FloatReal, Info);
13366	if (LHSOK) {
13367	LHS.makeComplexFloat();
13368	LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
13369	}
13370	} else {
13371	LHSOK = EvaluateComplex(E: E->getLHS(), Res&: LHS, Info);
13372	}
13373	if (!LHSOK && !Info.noteFailure())
13374	return false;
13375
13376	if (E->getRHS()->getType()->isRealFloatingType()) {
13377	if (!EvaluateFloat(E: E->getRHS(), Result&: RHS.FloatReal, Info) || !LHSOK)
13378	return false;
13379	RHS.makeComplexFloat();
13380	RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
13381	} else if (!EvaluateComplex(E: E->getRHS(), Res&: RHS, Info) || !LHSOK)
13382	return false;
13383
13384	if (LHS.isComplexFloat()) {
13385	APFloat::cmpResult CR_r =
13386	LHS.getComplexFloatReal().compare(RHS: RHS.getComplexFloatReal());
13387	APFloat::cmpResult CR_i =
13388	LHS.getComplexFloatImag().compare(RHS: RHS.getComplexFloatImag());
13389	bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
13390	return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
13391	} else {
13392	assert(IsEquality && "invalid complex comparison");
13393	bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
13394	LHS.getComplexIntImag() == RHS.getComplexIntImag();
13395	return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
13396	}
13397	}
13398
13399	if (LHSTy->isRealFloatingType() &&
13400	RHSTy->isRealFloatingType()) {
13401	APFloat RHS(0.0), LHS(0.0);
13402
13403	bool LHSOK = EvaluateFloat(E: E->getRHS(), Result&: RHS, Info);
13404	if (!LHSOK && !Info.noteFailure())
13405	return false;
13406
13407	if (!EvaluateFloat(E: E->getLHS(), Result&: LHS, Info) || !LHSOK)
13408	return false;
13409
13410	assert(E->isComparisonOp() && "Invalid binary operator!");
13411	llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS);
13412	if (!Info.InConstantContext &&
13413	APFloatCmpResult == APFloat::cmpUnordered &&
13414	E->getFPFeaturesInEffect(LO: Info.Ctx.getLangOpts()).isFPConstrained()) {
13415	// Note: Compares may raise invalid in some cases involving NaN or sNaN.
13416	Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
13417	return false;
13418	}
13419	auto GetCmpRes = [&]() {
13420	switch (APFloatCmpResult) {
13421	case APFloat::cmpEqual:
13422	return CmpResult::Equal;
13423	case APFloat::cmpLessThan:
13424	return CmpResult::Less;
13425	case APFloat::cmpGreaterThan:
13426	return CmpResult::Greater;
13427	case APFloat::cmpUnordered:
13428	return CmpResult::Unordered;
13429	}
13430	llvm_unreachable("Unrecognised APFloat::cmpResult enum");
13431	};
13432	return Success(GetCmpRes(), E);
13433	}
13434
13435	if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
13436	LValue LHSValue, RHSValue;
13437
13438	bool LHSOK = EvaluatePointer(E: E->getLHS(), Result&: LHSValue, Info);
13439	if (!LHSOK && !Info.noteFailure())
13440	return false;
13441
13442	if (!EvaluatePointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
13443	return false;
13444
13445	// Reject differing bases from the normal codepath; we special-case
13446	// comparisons to null.
13447	if (!HasSameBase(A: LHSValue, B: RHSValue)) {
13448	auto DiagComparison = [&] (unsigned DiagID, bool Reversed = false) {
13449	std::string LHS = LHSValue.toString(Ctx&: Info.Ctx, T: E->getLHS()->getType());
13450	std::string RHS = RHSValue.toString(Ctx&: Info.Ctx, T: E->getRHS()->getType());
13451	Info.FFDiag(E, DiagID)
13452	<< (Reversed ? RHS : LHS) << (Reversed ? LHS : RHS);
13453	return false;
13454	};
13455	// Inequalities and subtractions between unrelated pointers have
13456	// unspecified or undefined behavior.
13457	if (!IsEquality)
13458	return DiagComparison(
13459	diag::note_constexpr_pointer_comparison_unspecified);
13460	// A constant address may compare equal to the address of a symbol.
13461	// The one exception is that address of an object cannot compare equal
13462	// to a null pointer constant.
13463	// TODO: Should we restrict this to actual null pointers, and exclude the
13464	// case of zero cast to pointer type?
13465	if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
13466	(!RHSValue.Base && !RHSValue.Offset.isZero()))
13467	return DiagComparison(diag::note_constexpr_pointer_constant_comparison,
13468	!RHSValue.Base);
13469	// It's implementation-defined whether distinct literals will have
13470	// distinct addresses. In clang, the result of such a comparison is
13471	// unspecified, so it is not a constant expression. However, we do know
13472	// that the address of a literal will be non-null.
13473	if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
13474	LHSValue.Base && RHSValue.Base)
13475	return DiagComparison(diag::note_constexpr_literal_comparison);
13476	// We can't tell whether weak symbols will end up pointing to the same
13477	// object.
13478	if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
13479	return DiagComparison(diag::note_constexpr_pointer_weak_comparison,
13480	!IsWeakLValue(LHSValue));
13481	// We can't compare the address of the start of one object with the
13482	// past-the-end address of another object, per C++ DR1652.
13483	if (LHSValue.Base && LHSValue.Offset.isZero() &&
13484	isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue))
13485	return DiagComparison(diag::note_constexpr_pointer_comparison_past_end,
13486	true);
13487	if (RHSValue.Base && RHSValue.Offset.isZero() &&
13488	isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue))
13489	return DiagComparison(diag::note_constexpr_pointer_comparison_past_end,
13490	false);
13491	// We can't tell whether an object is at the same address as another
13492	// zero sized object.
13493	if ((RHSValue.Base && isZeroSized(LHSValue)) ||
13494	(LHSValue.Base && isZeroSized(RHSValue)))
13495	return DiagComparison(
13496	diag::note_constexpr_pointer_comparison_zero_sized);
13497	return Success(CmpResult::Unequal, E);
13498	}
13499
13500	const CharUnits &LHSOffset = LHSValue.getLValueOffset();
13501	const CharUnits &RHSOffset = RHSValue.getLValueOffset();
13502
13503	SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
13504	SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
13505
13506	// C++11 [expr.rel]p3:
13507	// Pointers to void (after pointer conversions) can be compared, with a
13508	// result defined as follows: If both pointers represent the same
13509	// address or are both the null pointer value, the result is true if the
13510	// operator is <= or >= and false otherwise; otherwise the result is
13511	// unspecified.
13512	// We interpret this as applying to pointers to *cv* void.
13513	if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational)
13514	Info.CCEDiag(E, diag::note_constexpr_void_comparison);
13515
13516	// C++11 [expr.rel]p2:
13517	// - If two pointers point to non-static data members of the same object,
13518	// or to subobjects or array elements fo such members, recursively, the
13519	// pointer to the later declared member compares greater provided the
13520	// two members have the same access control and provided their class is
13521	// not a union.
13522	// [...]
13523	// - Otherwise pointer comparisons are unspecified.
13524	if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
13525	bool WasArrayIndex;
13526	unsigned Mismatch = FindDesignatorMismatch(
13527	ObjType: getType(B: LHSValue.Base), A: LHSDesignator, B: RHSDesignator, WasArrayIndex);
13528	// At the point where the designators diverge, the comparison has a
13529	// specified value if:
13530	// - we are comparing array indices
13531	// - we are comparing fields of a union, or fields with the same access
13532	// Otherwise, the result is unspecified and thus the comparison is not a
13533	// constant expression.
13534	if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
13535	Mismatch < RHSDesignator.Entries.size()) {
13536	const FieldDecl *LF = getAsField(E: LHSDesignator.Entries[Mismatch]);
13537	const FieldDecl *RF = getAsField(E: RHSDesignator.Entries[Mismatch]);
13538	if (!LF && !RF)
13539	Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
13540	else if (!LF)
13541	Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
13542	<< getAsBaseClass(LHSDesignator.Entries[Mismatch])
13543	<< RF->getParent() << RF;
13544	else if (!RF)
13545	Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
13546	<< getAsBaseClass(RHSDesignator.Entries[Mismatch])
13547	<< LF->getParent() << LF;
13548	else if (!LF->getParent()->isUnion() &&
13549	LF->getAccess() != RF->getAccess())
13550	Info.CCEDiag(E,
13551	diag::note_constexpr_pointer_comparison_differing_access)
13552	<< LF << LF->getAccess() << RF << RF->getAccess()
13553	<< LF->getParent();
13554	}
13555	}
13556
13557	// The comparison here must be unsigned, and performed with the same
13558	// width as the pointer.
13559	unsigned PtrSize = Info.Ctx.getTypeSize(T: LHSTy);
13560	uint64_t CompareLHS = LHSOffset.getQuantity();
13561	uint64_t CompareRHS = RHSOffset.getQuantity();
13562	assert(PtrSize <= 64 && "Unexpected pointer width");
13563	uint64_t Mask = ~0ULL >> (64 - PtrSize);
13564	CompareLHS &= Mask;
13565	CompareRHS &= Mask;
13566
13567	// If there is a base and this is a relational operator, we can only
13568	// compare pointers within the object in question; otherwise, the result
13569	// depends on where the object is located in memory.
13570	if (!LHSValue.Base.isNull() && IsRelational) {
13571	QualType BaseTy = getType(B: LHSValue.Base);
13572	if (BaseTy->isIncompleteType())
13573	return Error(E);
13574	CharUnits Size = Info.Ctx.getTypeSizeInChars(T: BaseTy);
13575	uint64_t OffsetLimit = Size.getQuantity();
13576	if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
13577	return Error(E);
13578	}
13579
13580	if (CompareLHS < CompareRHS)
13581	return Success(CmpResult::Less, E);
13582	if (CompareLHS > CompareRHS)
13583	return Success(CmpResult::Greater, E);
13584	return Success(CmpResult::Equal, E);
13585	}
13586
13587	if (LHSTy->isMemberPointerType()) {
13588	assert(IsEquality && "unexpected member pointer operation");
13589	assert(RHSTy->isMemberPointerType() && "invalid comparison");
13590
13591	MemberPtr LHSValue, RHSValue;
13592
13593	bool LHSOK = EvaluateMemberPointer(E: E->getLHS(), Result&: LHSValue, Info);
13594	if (!LHSOK && !Info.noteFailure())
13595	return false;
13596
13597	if (!EvaluateMemberPointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
13598	return false;
13599
13600	// If either operand is a pointer to a weak function, the comparison is not
13601	// constant.
13602	if (LHSValue.getDecl() && LHSValue.getDecl()->isWeak()) {
13603	Info.FFDiag(E, diag::note_constexpr_mem_pointer_weak_comparison)
13604	<< LHSValue.getDecl();
13605	return false;
13606	}
13607	if (RHSValue.getDecl() && RHSValue.getDecl()->isWeak()) {
13608	Info.FFDiag(E, diag::note_constexpr_mem_pointer_weak_comparison)
13609	<< RHSValue.getDecl();
13610	return false;
13611	}
13612
13613	// C++11 [expr.eq]p2:
13614	// If both operands are null, they compare equal. Otherwise if only one is
13615	// null, they compare unequal.
13616	if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
13617	bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
13618	return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
13619	}
13620
13621	// Otherwise if either is a pointer to a virtual member function, the
13622	// result is unspecified.
13623	if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
13624	if (MD->isVirtual())
13625	Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
13626	if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
13627	if (MD->isVirtual())
13628	Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
13629
13630	// Otherwise they compare equal if and only if they would refer to the
13631	// same member of the same most derived object or the same subobject if
13632	// they were dereferenced with a hypothetical object of the associated
13633	// class type.
13634	bool Equal = LHSValue == RHSValue;
13635	return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
13636	}
13637
13638	if (LHSTy->isNullPtrType()) {
13639	assert(E->isComparisonOp() && "unexpected nullptr operation");
13640	assert(RHSTy->isNullPtrType() && "missing pointer conversion");
13641	// C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
13642	// are compared, the result is true of the operator is <=, >= or ==, and
13643	// false otherwise.
13644	LValue Res;
13645	if (!EvaluatePointer(E: E->getLHS(), Result&: Res, Info) ||
13646	!EvaluatePointer(E: E->getRHS(), Result&: Res, Info))
13647	return false;
13648	return Success(CmpResult::Equal, E);
13649	}
13650
13651	return DoAfter();
13652	}
13653
13654	bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
13655	if (!CheckLiteralType(Info, E))
13656	return false;
13657
13658	auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
13659	ComparisonCategoryResult CCR;
13660	switch (CR) {
13661	case CmpResult::Unequal:
13662	llvm_unreachable("should never produce Unequal for three-way comparison");
13663	case CmpResult::Less:
13664	CCR = ComparisonCategoryResult::Less;
13665	break;
13666	case CmpResult::Equal:
13667	CCR = ComparisonCategoryResult::Equal;
13668	break;
13669	case CmpResult::Greater:
13670	CCR = ComparisonCategoryResult::Greater;
13671	break;
13672	case CmpResult::Unordered:
13673	CCR = ComparisonCategoryResult::Unordered;
13674	break;
13675	}
13676	// Evaluation succeeded. Lookup the information for the comparison category
13677	// type and fetch the VarDecl for the result.
13678	const ComparisonCategoryInfo &CmpInfo =
13679	Info.Ctx.CompCategories.getInfoForType(Ty: E->getType());
13680	const VarDecl *VD = CmpInfo.getValueInfo(ValueKind: CmpInfo.makeWeakResult(Res: CCR))->VD;
13681	// Check and evaluate the result as a constant expression.
13682	LValue LV;
13683	LV.set(VD);
13684	if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
13685	return false;
13686	return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
13687	ConstantExprKind::Normal);
13688	};
13689	return EvaluateComparisonBinaryOperator(Info, E, Success&: OnSuccess, DoAfter: [&]() {
13690	return ExprEvaluatorBaseTy::VisitBinCmp(E);
13691	});
13692	}
13693
13694	bool RecordExprEvaluator::VisitCXXParenListInitExpr(
13695	const CXXParenListInitExpr *E) {
13696	return VisitCXXParenListOrInitListExpr(E, E->getInitExprs());
13697	}
13698
13699	bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13700	// We don't support assignment in C. C++ assignments don't get here because
13701	// assignment is an lvalue in C++.
13702	if (E->isAssignmentOp()) {
13703	Error(E);
13704	if (!Info.noteFailure())
13705	return false;
13706	}
13707
13708	if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
13709	return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
13710
13711	assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||
13712	!E->getRHS()->getType()->isIntegralOrEnumerationType()) &&
13713	"DataRecursiveIntBinOpEvaluator should have handled integral types");
13714
13715	if (E->isComparisonOp()) {
13716	// Evaluate builtin binary comparisons by evaluating them as three-way
13717	// comparisons and then translating the result.
13718	auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
13719	assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&
13720	"should only produce Unequal for equality comparisons");
13721	bool IsEqual = CR == CmpResult::Equal,
13722	IsLess = CR == CmpResult::Less,
13723	IsGreater = CR == CmpResult::Greater;
13724	auto Op = E->getOpcode();
13725	switch (Op) {
13726	default:
13727	llvm_unreachable("unsupported binary operator");
13728	case BO_EQ:
13729	case BO_NE:
13730	return Success(IsEqual == (Op == BO_EQ), E);
13731	case BO_LT:
13732	return Success(IsLess, E);
13733	case BO_GT:
13734	return Success(IsGreater, E);
13735	case BO_LE:
13736	return Success(IsEqual || IsLess, E);
13737	case BO_GE:
13738	return Success(IsEqual || IsGreater, E);
13739	}
13740	};
13741	return EvaluateComparisonBinaryOperator(Info, E, Success&: OnSuccess, DoAfter: [&]() {
13742	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13743	});
13744	}
13745
13746	QualType LHSTy = E->getLHS()->getType();
13747	QualType RHSTy = E->getRHS()->getType();
13748
13749	if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
13750	E->getOpcode() == BO_Sub) {
13751	LValue LHSValue, RHSValue;
13752
13753	bool LHSOK = EvaluatePointer(E: E->getLHS(), Result&: LHSValue, Info);
13754	if (!LHSOK && !Info.noteFailure())
13755	return false;
13756
13757	if (!EvaluatePointer(E: E->getRHS(), Result&: RHSValue, Info) || !LHSOK)
13758	return false;
13759
13760	// Reject differing bases from the normal codepath; we special-case
13761	// comparisons to null.
13762	if (!HasSameBase(A: LHSValue, B: RHSValue)) {
13763	// Handle &&A - &&B.
13764	if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
13765	return Error(E);
13766	const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
13767	const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
13768	if (!LHSExpr || !RHSExpr)
13769	return Error(E);
13770	const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: LHSExpr);
13771	const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(Val: RHSExpr);
13772	if (!LHSAddrExpr || !RHSAddrExpr)
13773	return Error(E);
13774	// Make sure both labels come from the same function.
13775	if (LHSAddrExpr->getLabel()->getDeclContext() !=
13776	RHSAddrExpr->getLabel()->getDeclContext())
13777	return Error(E);
13778	return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
13779	}
13780	const CharUnits &LHSOffset = LHSValue.getLValueOffset();
13781	const CharUnits &RHSOffset = RHSValue.getLValueOffset();
13782
13783	SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
13784	SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
13785
13786	// C++11 [expr.add]p6:
13787	// Unless both pointers point to elements of the same array object, or
13788	// one past the last element of the array object, the behavior is
13789	// undefined.
13790	if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
13791	!AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator,
13792	RHSDesignator))
13793	Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
13794
13795	QualType Type = E->getLHS()->getType();
13796	QualType ElementType = Type->castAs<PointerType>()->getPointeeType();
13797
13798	CharUnits ElementSize;
13799	if (!HandleSizeof(Info, Loc: E->getExprLoc(), Type: ElementType, Size&: ElementSize))
13800	return false;
13801
13802	// As an extension, a type may have zero size (empty struct or union in
13803	// C, array of zero length). Pointer subtraction in such cases has
13804	// undefined behavior, so is not constant.
13805	if (ElementSize.isZero()) {
13806	Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
13807	<< ElementType;
13808	return false;
13809	}
13810
13811	// FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
13812	// and produce incorrect results when it overflows. Such behavior
13813	// appears to be non-conforming, but is common, so perhaps we should
13814	// assume the standard intended for such cases to be undefined behavior
13815	// and check for them.
13816
13817	// Compute (LHSOffset - RHSOffset) / Size carefully, checking for
13818	// overflow in the final conversion to ptrdiff_t.
13819	APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
13820	APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
13821	APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
13822	false);
13823	APSInt TrueResult = (LHS - RHS) / ElemSize;
13824	APSInt Result = TrueResult.trunc(width: Info.Ctx.getIntWidth(T: E->getType()));
13825
13826	if (Result.extend(width: 65) != TrueResult &&
13827	!HandleOverflow(Info, E, TrueResult, E->getType()))
13828	return false;
13829	return Success(Result, E);
13830	}
13831
13832	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13833	}
13834
13835	/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
13836	/// a result as the expression's type.
13837	bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
13838	const UnaryExprOrTypeTraitExpr *E) {
13839	switch(E->getKind()) {
13840	case UETT_PreferredAlignOf:
13841	case UETT_AlignOf: {
13842	if (E->isArgumentType())
13843	return Success(GetAlignOfType(Info, T: E->getArgumentType(), ExprKind: E->getKind()),
13844	E);
13845	else
13846	return Success(GetAlignOfExpr(Info, E: E->getArgumentExpr(), ExprKind: E->getKind()),
13847	E);
13848	}
13849
13850	case UETT_VecStep: {
13851	QualType Ty = E->getTypeOfArgument();
13852
13853	if (Ty->isVectorType()) {
13854	unsigned n = Ty->castAs<VectorType>()->getNumElements();
13855
13856	// The vec_step built-in functions that take a 3-component
13857	// vector return 4. (OpenCL 1.1 spec 6.11.12)
13858	if (n == 3)
13859	n = 4;
13860
13861	return Success(n, E);
13862	} else
13863	return Success(1, E);
13864	}
13865
13866	case UETT_DataSizeOf:
13867	case UETT_SizeOf: {
13868	QualType SrcTy = E->getTypeOfArgument();
13869	// C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
13870	// the result is the size of the referenced type."
13871	if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
13872	SrcTy = Ref->getPointeeType();
13873
13874	CharUnits Sizeof;
13875	if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof,
13876	E->getKind() == UETT_DataSizeOf ? SizeOfType::DataSizeOf
13877	: SizeOfType::SizeOf)) {
13878	return false;
13879	}
13880	return Success(Sizeof, E);
13881	}
13882	case UETT_OpenMPRequiredSimdAlign:
13883	assert(E->isArgumentType());
13884	return Success(
13885	Info.Ctx.toCharUnitsFromBits(
13886	BitSize: Info.Ctx.getOpenMPDefaultSimdAlign(T: E->getArgumentType()))
13887	.getQuantity(),
13888	E);
13889	case UETT_VectorElements: {
13890	QualType Ty = E->getTypeOfArgument();
13891	// If the vector has a fixed size, we can determine the number of elements
13892	// at compile time.
13893	if (Ty->isVectorType())
13894	return Success(Ty->castAs<VectorType>()->getNumElements(), E);
13895
13896	assert(Ty->isSizelessVectorType());
13897	if (Info.InConstantContext)
13898	Info.CCEDiag(E, diag::note_constexpr_non_const_vectorelements)
13899	<< E->getSourceRange();
13900
13901	return false;
13902	}
13903	}
13904
13905	llvm_unreachable("unknown expr/type trait");
13906	}
13907
13908	bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
13909	CharUnits Result;
13910	unsigned n = OOE->getNumComponents();
13911	if (n == 0)
13912	return Error(OOE);
13913	QualType CurrentType = OOE->getTypeSourceInfo()->getType();
13914	for (unsigned i = 0; i != n; ++i) {
13915	OffsetOfNode ON = OOE->getComponent(Idx: i);
13916	switch (ON.getKind()) {
13917	case OffsetOfNode::Array: {
13918	const Expr *Idx = OOE->getIndexExpr(Idx: ON.getArrayExprIndex());
13919	APSInt IdxResult;
13920	if (!EvaluateInteger(E: Idx, Result&: IdxResult, Info))
13921	return false;
13922	const ArrayType *AT = Info.Ctx.getAsArrayType(T: CurrentType);
13923	if (!AT)
13924	return Error(OOE);
13925	CurrentType = AT->getElementType();
13926	CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(T: CurrentType);
13927	Result += IdxResult.getSExtValue() * ElementSize;
13928	break;
13929	}
13930
13931	case OffsetOfNode::Field: {
13932	FieldDecl *MemberDecl = ON.getField();
13933	const RecordType *RT = CurrentType->getAs<RecordType>();
13934	if (!RT)
13935	return Error(OOE);
13936	RecordDecl *RD = RT->getDecl();
13937	if (RD->isInvalidDecl()) return false;
13938	const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(D: RD);
13939	unsigned i = MemberDecl->getFieldIndex();
13940	assert(i < RL.getFieldCount() && "offsetof field in wrong type");
13941	Result += Info.Ctx.toCharUnitsFromBits(BitSize: RL.getFieldOffset(FieldNo: i));
13942	CurrentType = MemberDecl->getType().getNonReferenceType();
13943	break;
13944	}
13945
13946	case OffsetOfNode::Identifier:
13947	llvm_unreachable("dependent __builtin_offsetof");
13948
13949	case OffsetOfNode::Base: {
13950	CXXBaseSpecifier *BaseSpec = ON.getBase();
13951	if (BaseSpec->isVirtual())
13952	return Error(OOE);
13953
13954	// Find the layout of the class whose base we are looking into.
13955	const RecordType *RT = CurrentType->getAs<RecordType>();
13956	if (!RT)
13957	return Error(OOE);
13958	RecordDecl *RD = RT->getDecl();
13959	if (RD->isInvalidDecl()) return false;
13960	const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(D: RD);
13961
13962	// Find the base class itself.
13963	CurrentType = BaseSpec->getType();
13964	const RecordType *BaseRT = CurrentType->getAs<RecordType>();
13965	if (!BaseRT)
13966	return Error(OOE);
13967
13968	// Add the offset to the base.
13969	Result += RL.getBaseClassOffset(Base: cast<CXXRecordDecl>(Val: BaseRT->getDecl()));
13970	break;
13971	}
13972	}
13973	}
13974	return Success(Result, OOE);
13975	}
13976
13977	bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13978	switch (E->getOpcode()) {
13979	default:
13980	// Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
13981	// See C99 6.6p3.
13982	return Error(E);
13983	case UO_Extension:
13984	// FIXME: Should extension allow i-c-e extension expressions in its scope?
13985	// If so, we could clear the diagnostic ID.
13986	return Visit(E->getSubExpr());
13987	case UO_Plus:
13988	// The result is just the value.
13989	return Visit(E->getSubExpr());
13990	case UO_Minus: {
13991	if (!Visit(E->getSubExpr()))
13992	return false;
13993	if (!Result.isInt()) return Error(E);
13994	const APSInt &Value = Result.getInt();
13995	if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow()) {
13996	if (Info.checkingForUndefinedBehavior())
13997	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13998	diag::warn_integer_constant_overflow)
13999	<< toString(Value, 10, Value.isSigned(), /*formatAsCLiteral=*/false,
14000	/*UpperCase=*/true, /*InsertSeparators=*/true)
14001	<< E->getType() << E->getSourceRange();
14002
14003	if (!HandleOverflow(Info, E, -Value.extend(width: Value.getBitWidth() + 1),
14004	E->getType()))
14005	return false;
14006	}
14007	return Success(-Value, E);
14008	}
14009	case UO_Not: {
14010	if (!Visit(E->getSubExpr()))
14011	return false;
14012	if (!Result.isInt()) return Error(E);
14013	return Success(~Result.getInt(), E);
14014	}
14015	case UO_LNot: {
14016	bool bres;
14017	if (!EvaluateAsBooleanCondition(E: E->getSubExpr(), Result&: bres, Info))
14018	return false;
14019	return Success(!bres, E);
14020	}
14021	}
14022	}
14023
14024	/// HandleCast - This is used to evaluate implicit or explicit casts where the
14025	/// result type is integer.
14026	bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
14027	const Expr *SubExpr = E->getSubExpr();
14028	QualType DestType = E->getType();
14029	QualType SrcType = SubExpr->getType();
14030
14031	switch (E->getCastKind()) {
14032	case CK_BaseToDerived:
14033	case CK_DerivedToBase:
14034	case CK_UncheckedDerivedToBase:
14035	case CK_Dynamic:
14036	case CK_ToUnion:
14037	case CK_ArrayToPointerDecay:
14038	case CK_FunctionToPointerDecay:
14039	case CK_NullToPointer:
14040	case CK_NullToMemberPointer:
14041	case CK_BaseToDerivedMemberPointer:
14042	case CK_DerivedToBaseMemberPointer:
14043	case CK_ReinterpretMemberPointer:
14044	case CK_ConstructorConversion:
14045	case CK_IntegralToPointer:
14046	case CK_ToVoid:
14047	case CK_VectorSplat:
14048	case CK_IntegralToFloating:
14049	case CK_FloatingCast:
14050	case CK_CPointerToObjCPointerCast:
14051	case CK_BlockPointerToObjCPointerCast:
14052	case CK_AnyPointerToBlockPointerCast:
14053	case CK_ObjCObjectLValueCast:
14054	case CK_FloatingRealToComplex:
14055	case CK_FloatingComplexToReal:
14056	case CK_FloatingComplexCast:
14057	case CK_FloatingComplexToIntegralComplex:
14058	case CK_IntegralRealToComplex:
14059	case CK_IntegralComplexCast:
14060	case CK_IntegralComplexToFloatingComplex:
14061	case CK_BuiltinFnToFnPtr:
14062	case CK_ZeroToOCLOpaqueType:
14063	case CK_NonAtomicToAtomic:
14064	case CK_AddressSpaceConversion:
14065	case CK_IntToOCLSampler:
14066	case CK_FloatingToFixedPoint:
14067	case CK_FixedPointToFloating:
14068	case CK_FixedPointCast:
14069	case CK_IntegralToFixedPoint:
14070	case CK_MatrixCast:
14071	case CK_HLSLVectorTruncation:
14072	llvm_unreachable("invalid cast kind for integral value");
14073
14074	case CK_BitCast:
14075	case CK_Dependent:
14076	case CK_LValueBitCast:
14077	case CK_ARCProduceObject:
14078	case CK_ARCConsumeObject:
14079	case CK_ARCReclaimReturnedObject:
14080	case CK_ARCExtendBlockObject:
14081	case CK_CopyAndAutoreleaseBlockObject:
14082	return Error(E);
14083
14084	case CK_UserDefinedConversion:
14085	case CK_LValueToRValue:
14086	case CK_AtomicToNonAtomic:
14087	case CK_NoOp:
14088	case CK_LValueToRValueBitCast:
14089	case CK_HLSLArrayRValue:
14090	return ExprEvaluatorBaseTy::VisitCastExpr(E);
14091
14092	case CK_MemberPointerToBoolean:
14093	case CK_PointerToBoolean:
14094	case CK_IntegralToBoolean:
14095	case CK_FloatingToBoolean:
14096	case CK_BooleanToSignedIntegral:
14097	case CK_FloatingComplexToBoolean:
14098	case CK_IntegralComplexToBoolean: {
14099	bool BoolResult;
14100	if (!EvaluateAsBooleanCondition(E: SubExpr, Result&: BoolResult, Info))
14101	return false;
14102	uint64_t IntResult = BoolResult;
14103	if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
14104	IntResult = (uint64_t)-1;
14105	return Success(IntResult, E);
14106	}
14107
14108	case CK_FixedPointToIntegral: {
14109	APFixedPoint Src(Info.Ctx.getFixedPointSemantics(Ty: SrcType));
14110	if (!EvaluateFixedPoint(E: SubExpr, Result&: Src, Info))
14111	return false;
14112	bool Overflowed;
14113	llvm::APSInt Result = Src.convertToInt(
14114	DstWidth: Info.Ctx.getIntWidth(T: DestType),
14115	DstSign: DestType->isSignedIntegerOrEnumerationType(), Overflow: &Overflowed);
14116	if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
14117	return false;
14118	return Success(Result, E);
14119	}
14120
14121	case CK_FixedPointToBoolean: {
14122	// Unsigned padding does not affect this.
14123	APValue Val;
14124	if (!Evaluate(Result&: Val, Info, E: SubExpr))
14125	return false;
14126	return Success(Val.getFixedPoint().getBoolValue(), E);
14127	}
14128
14129	case CK_IntegralCast: {
14130	if (!Visit(SubExpr))
14131	return false;
14132
14133	if (!Result.isInt()) {
14134	// Allow casts of address-of-label differences if they are no-ops
14135	// or narrowing. (The narrowing case isn't actually guaranteed to
14136	// be constant-evaluatable except in some narrow cases which are hard
14137	// to detect here. We let it through on the assumption the user knows
14138	// what they are doing.)
14139	if (Result.isAddrLabelDiff())
14140	return Info.Ctx.getTypeSize(T: DestType) <= Info.Ctx.getTypeSize(T: SrcType);
14141	// Only allow casts of lvalues if they are lossless.
14142	return Info.Ctx.getTypeSize(T: DestType) == Info.Ctx.getTypeSize(T: SrcType);
14143	}
14144
14145	if (Info.Ctx.getLangOpts().CPlusPlus && Info.InConstantContext &&
14146	Info.EvalMode == EvalInfo::EM_ConstantExpression &&
14147	DestType->isEnumeralType()) {
14148
14149	bool ConstexprVar = true;
14150
14151	// We know if we are here that we are in a context that we might require
14152	// a constant expression or a context that requires a constant
14153	// value. But if we are initializing a value we don't know if it is a
14154	// constexpr variable or not. We can check the EvaluatingDecl to determine
14155	// if it constexpr or not. If not then we don't want to emit a diagnostic.
14156	if (const auto *VD = dyn_cast_or_null<VarDecl>(
14157	Val: Info.EvaluatingDecl.dyn_cast<const ValueDecl *>()))
14158	ConstexprVar = VD->isConstexpr();
14159
14160	const EnumType *ET = dyn_cast<EnumType>(Val: DestType.getCanonicalType());
14161	const EnumDecl *ED = ET->getDecl();
14162	// Check that the value is within the range of the enumeration values.
14163	//
14164	// This corressponds to [expr.static.cast]p10 which says:
14165	// A value of integral or enumeration type can be explicitly converted
14166	// to a complete enumeration type ... If the enumeration type does not
14167	// have a fixed underlying type, the value is unchanged if the original
14168	// value is within the range of the enumeration values ([dcl.enum]), and
14169	// otherwise, the behavior is undefined.
14170	//
14171	// This was resolved as part of DR2338 which has CD5 status.
14172	if (!ED->isFixed()) {
14173	llvm::APInt Min;
14174	llvm::APInt Max;
14175
14176	ED->getValueRange(Max, Min);
14177	--Max;
14178
14179	if (ED->getNumNegativeBits() && ConstexprVar &&
14180	(Max.slt(Result.getInt().getSExtValue()) ||
14181	Min.sgt(Result.getInt().getSExtValue())))
14182	Info.Ctx.getDiagnostics().Report(
14183	E->getExprLoc(), diag::warn_constexpr_unscoped_enum_out_of_range)
14184	<< llvm::toString(Result.getInt(), 10) << Min.getSExtValue()
14185	<< Max.getSExtValue() << ED;
14186	else if (!ED->getNumNegativeBits() && ConstexprVar &&
14187	Max.ult(Result.getInt().getZExtValue()))
14188	Info.Ctx.getDiagnostics().Report(
14189	E->getExprLoc(), diag::warn_constexpr_unscoped_enum_out_of_range)
14190	<< llvm::toString(Result.getInt(), 10) << Min.getZExtValue()
14191	<< Max.getZExtValue() << ED;
14192	}
14193	}
14194
14195	return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
14196	Result.getInt()), E);
14197	}
14198
14199	case CK_PointerToIntegral: {
14200	CCEDiag(E, diag::note_constexpr_invalid_cast)
14201	<< 2 << Info.Ctx.getLangOpts().CPlusPlus << E->getSourceRange();
14202
14203	LValue LV;
14204	if (!EvaluatePointer(E: SubExpr, Result&: LV, Info))
14205	return false;
14206
14207	if (LV.getLValueBase()) {
14208	// Only allow based lvalue casts if they are lossless.
14209	// FIXME: Allow a larger integer size than the pointer size, and allow
14210	// narrowing back down to pointer width in subsequent integral casts.
14211	// FIXME: Check integer type's active bits, not its type size.
14212	if (Info.Ctx.getTypeSize(T: DestType) != Info.Ctx.getTypeSize(T: SrcType))
14213	return Error(E);
14214
14215	LV.Designator.setInvalid();
14216	LV.moveInto(V&: Result);
14217	return true;
14218	}
14219
14220	APSInt AsInt;
14221	APValue V;
14222	LV.moveInto(V);
14223	if (!V.toIntegralConstant(Result&: AsInt, SrcTy: SrcType, Ctx: Info.Ctx))
14224	llvm_unreachable("Can't cast this!");
14225
14226	return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
14227	}
14228
14229	case CK_IntegralComplexToReal: {
14230	ComplexValue C;
14231	if (!EvaluateComplex(E: SubExpr, Res&: C, Info))
14232	return false;
14233	return Success(C.getComplexIntReal(), E);
14234	}
14235
14236	case CK_FloatingToIntegral: {
14237	APFloat F(0.0);
14238	if (!EvaluateFloat(E: SubExpr, Result&: F, Info))
14239	return false;
14240
14241	APSInt Value;
14242	if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
14243	return false;
14244	return Success(Value, E);
14245	}
14246	}
14247
14248	llvm_unreachable("unknown cast resulting in integral value");
14249	}
14250
14251	bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
14252	if (E->getSubExpr()->getType()->isAnyComplexType()) {
14253	ComplexValue LV;
14254	if (!EvaluateComplex(E: E->getSubExpr(), Res&: LV, Info))
14255	return false;
14256	if (!LV.isComplexInt())
14257	return Error(E);
14258	return Success(LV.getComplexIntReal(), E);
14259	}
14260
14261	return Visit(E->getSubExpr());
14262	}
14263
14264	bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
14265	if (E->getSubExpr()->getType()->isComplexIntegerType()) {
14266	ComplexValue LV;
14267	if (!EvaluateComplex(E: E->getSubExpr(), Res&: LV, Info))
14268	return false;
14269	if (!LV.isComplexInt())
14270	return Error(E);
14271	return Success(LV.getComplexIntImag(), E);
14272	}
14273
14274	VisitIgnoredValue(E: E->getSubExpr());
14275	return Success(0, E);
14276	}
14277
14278	bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
14279	return Success(E->getPackLength(), E);
14280	}
14281
14282	bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
14283	return Success(E->getValue(), E);
14284	}
14285
14286	bool IntExprEvaluator::VisitConceptSpecializationExpr(
14287	const ConceptSpecializationExpr *E) {
14288	return Success(E->isSatisfied(), E);
14289	}
14290
14291	bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
14292	return Success(E->isSatisfied(), E);
14293	}
14294
14295	bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
14296	switch (E->getOpcode()) {
14297	default:
14298	// Invalid unary operators
14299	return Error(E);
14300	case UO_Plus:
14301	// The result is just the value.
14302	return Visit(E->getSubExpr());
14303	case UO_Minus: {
14304	if (!Visit(E->getSubExpr())) return false;
14305	if (!Result.isFixedPoint())
14306	return Error(E);
14307	bool Overflowed;
14308	APFixedPoint Negated = Result.getFixedPoint().negate(Overflow: &Overflowed);
14309	if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
14310	return false;
14311	return Success(Negated, E);
14312	}
14313	case UO_LNot: {
14314	bool bres;
14315	if (!EvaluateAsBooleanCondition(E: E->getSubExpr(), Result&: bres, Info))
14316	return false;
14317	return Success(!bres, E);
14318	}
14319	}
14320	}
14321
14322	bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
14323	const Expr *SubExpr = E->getSubExpr();
14324	QualType DestType = E->getType();
14325	assert(DestType->isFixedPointType() &&
14326	"Expected destination type to be a fixed point type");
14327	auto DestFXSema = Info.Ctx.getFixedPointSemantics(Ty: DestType);
14328
14329	switch (E->getCastKind()) {
14330	case CK_FixedPointCast: {
14331	APFixedPoint Src(Info.Ctx.getFixedPointSemantics(Ty: SubExpr->getType()));
14332	if (!EvaluateFixedPoint(E: SubExpr, Result&: Src, Info))
14333	return false;
14334	bool Overflowed;
14335	APFixedPoint Result = Src.convert(DstSema: DestFXSema, Overflow: &Overflowed);
14336	if (Overflowed) {
14337	if (Info.checkingForUndefinedBehavior())
14338	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
14339	diag::warn_fixedpoint_constant_overflow)
14340	<< Result.toString() << E->getType();
14341	if (!HandleOverflow(Info, E, Result, E->getType()))
14342	return false;
14343	}
14344	return Success(Result, E);
14345	}
14346	case CK_IntegralToFixedPoint: {
14347	APSInt Src;
14348	if (!EvaluateInteger(E: SubExpr, Result&: Src, Info))
14349	return false;
14350
14351	bool Overflowed;
14352	APFixedPoint IntResult = APFixedPoint::getFromIntValue(
14353	Value: Src, DstFXSema: Info.Ctx.getFixedPointSemantics(Ty: DestType), Overflow: &Overflowed);
14354
14355	if (Overflowed) {
14356	if (Info.checkingForUndefinedBehavior())
14357	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
14358	diag::warn_fixedpoint_constant_overflow)
14359	<< IntResult.toString() << E->getType();
14360	if (!HandleOverflow(Info, E, IntResult, E->getType()))
14361	return false;
14362	}
14363
14364	return Success(IntResult, E);
14365	}
14366	case CK_FloatingToFixedPoint: {
14367	APFloat Src(0.0);
14368	if (!EvaluateFloat(E: SubExpr, Result&: Src, Info))
14369	return false;
14370
14371	bool Overflowed;
14372	APFixedPoint Result = APFixedPoint::getFromFloatValue(
14373	Value: Src, DstFXSema: Info.Ctx.getFixedPointSemantics(Ty: DestType), Overflow: &Overflowed);
14374
14375	if (Overflowed) {
14376	if (Info.checkingForUndefinedBehavior())
14377	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
14378	diag::warn_fixedpoint_constant_overflow)
14379	<< Result.toString() << E->getType();
14380	if (!HandleOverflow(Info, E, Result, E->getType()))
14381	return false;
14382	}
14383
14384	return Success(Result, E);
14385	}
14386	case CK_NoOp:
14387	case CK_LValueToRValue:
14388	return ExprEvaluatorBaseTy::VisitCastExpr(E);
14389	default:
14390	return Error(E);
14391	}
14392	}
14393
14394	bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
14395	if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
14396	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14397
14398	const Expr *LHS = E->getLHS();
14399	const Expr *RHS = E->getRHS();
14400	FixedPointSemantics ResultFXSema =
14401	Info.Ctx.getFixedPointSemantics(Ty: E->getType());
14402
14403	APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(Ty: LHS->getType()));
14404	if (!EvaluateFixedPointOrInteger(E: LHS, Result&: LHSFX, Info))
14405	return false;
14406	APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(Ty: RHS->getType()));
14407	if (!EvaluateFixedPointOrInteger(E: RHS, Result&: RHSFX, Info))
14408	return false;
14409
14410	bool OpOverflow = false, ConversionOverflow = false;
14411	APFixedPoint Result(LHSFX.getSemantics());
14412	switch (E->getOpcode()) {
14413	case BO_Add: {
14414	Result = LHSFX.add(Other: RHSFX, Overflow: &OpOverflow)
14415	.convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
14416	break;
14417	}
14418	case BO_Sub: {
14419	Result = LHSFX.sub(Other: RHSFX, Overflow: &OpOverflow)
14420	.convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
14421	break;
14422	}
14423	case BO_Mul: {
14424	Result = LHSFX.mul(Other: RHSFX, Overflow: &OpOverflow)
14425	.convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
14426	break;
14427	}
14428	case BO_Div: {
14429	if (RHSFX.getValue() == 0) {
14430	Info.FFDiag(E, diag::note_expr_divide_by_zero);
14431	return false;
14432	}
14433	Result = LHSFX.div(Other: RHSFX, Overflow: &OpOverflow)
14434	.convert(DstSema: ResultFXSema, Overflow: &ConversionOverflow);
14435	break;
14436	}
14437	case BO_Shl:
14438	case BO_Shr: {
14439	FixedPointSemantics LHSSema = LHSFX.getSemantics();
14440	llvm::APSInt RHSVal = RHSFX.getValue();
14441
14442	unsigned ShiftBW =
14443	LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding();
14444	unsigned Amt = RHSVal.getLimitedValue(Limit: ShiftBW - 1);
14445	// Embedded-C 4.1.6.2.2:
14446	// The right operand must be nonnegative and less than the total number
14447	// of (nonpadding) bits of the fixed-point operand ...
14448	if (RHSVal.isNegative())
14449	Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHSVal;
14450	else if (Amt != RHSVal)
14451	Info.CCEDiag(E, diag::note_constexpr_large_shift)
14452	<< RHSVal << E->getType() << ShiftBW;
14453
14454	if (E->getOpcode() == BO_Shl)
14455	Result = LHSFX.shl(Amt, Overflow: &OpOverflow);
14456	else
14457	Result = LHSFX.shr(Amt, Overflow: &OpOverflow);
14458	break;
14459	}
14460	default:
14461	return false;
14462	}
14463	if (OpOverflow || ConversionOverflow) {
14464	if (Info.checkingForUndefinedBehavior())
14465	Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
14466	diag::warn_fixedpoint_constant_overflow)
14467	<< Result.toString() << E->getType();
14468	if (!HandleOverflow(Info, E, Result, E->getType()))
14469	return false;
14470	}
14471	return Success(Result, E);
14472	}
14473
14474	//===----------------------------------------------------------------------===//
14475	// Float Evaluation
14476	//===----------------------------------------------------------------------===//
14477
14478	namespace {
14479	class FloatExprEvaluator
14480	: public ExprEvaluatorBase<FloatExprEvaluator> {
14481	APFloat &Result;
14482	public:
14483	FloatExprEvaluator(EvalInfo &info, APFloat &result)
14484	: ExprEvaluatorBaseTy(info), Result(result) {}
14485
14486	bool Success(const APValue &V, const Expr *e) {
14487	Result = V.getFloat();
14488	return true;
14489	}
14490
14491	bool ZeroInitialization(const Expr *E) {
14492	Result = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: E->getType()));
14493	return true;
14494	}
14495
14496	bool VisitCallExpr(const CallExpr *E);
14497
14498	bool VisitUnaryOperator(const UnaryOperator *E);
14499	bool VisitBinaryOperator(const BinaryOperator *E);
14500	bool VisitFloatingLiteral(const FloatingLiteral *E);
14501	bool VisitCastExpr(const CastExpr *E);
14502
14503	bool VisitUnaryReal(const UnaryOperator *E);
14504	bool VisitUnaryImag(const UnaryOperator *E);
14505
14506	// FIXME: Missing: array subscript of vector, member of vector
14507	};
14508	} // end anonymous namespace
14509
14510	static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
14511	assert(!E->isValueDependent());
14512	assert(E->isPRValue() && E->getType()->isRealFloatingType());
14513	return FloatExprEvaluator(Info, Result).Visit(E);
14514	}
14515
14516	static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
14517	QualType ResultTy,
14518	const Expr *Arg,
14519	bool SNaN,
14520	llvm::APFloat &Result) {
14521	const StringLiteral *S = dyn_cast<StringLiteral>(Val: Arg->IgnoreParenCasts());
14522	if (!S) return false;
14523
14524	const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(T: ResultTy);
14525
14526	llvm::APInt fill;
14527
14528	// Treat empty strings as if they were zero.
14529	if (S->getString().empty())
14530	fill = llvm::APInt(32, 0);
14531	else if (S->getString().getAsInteger(Radix: 0, Result&: fill))
14532	return false;
14533
14534	if (Context.getTargetInfo().isNan2008()) {
14535	if (SNaN)
14536	Result = llvm::APFloat::getSNaN(Sem, Negative: false, payload: &fill);
14537	else
14538	Result = llvm::APFloat::getQNaN(Sem, Negative: false, payload: &fill);
14539	} else {
14540	// Prior to IEEE 754-2008, architectures were allowed to choose whether
14541	// the first bit of their significand was set for qNaN or sNaN. MIPS chose
14542	// a different encoding to what became a standard in 2008, and for pre-
14543	// 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
14544	// sNaN. This is now known as "legacy NaN" encoding.
14545	if (SNaN)
14546	Result = llvm::APFloat::getQNaN(Sem, Negative: false, payload: &fill);
14547	else
14548	Result = llvm::APFloat::getSNaN(Sem, Negative: false, payload: &fill);
14549	}
14550
14551	return true;
14552	}
14553
14554	bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
14555	if (!IsConstantEvaluatedBuiltinCall(E))
14556	return ExprEvaluatorBaseTy::VisitCallExpr(E);
14557
14558	switch (E->getBuiltinCallee()) {
14559	default:
14560	return false;
14561
14562	case Builtin::BI__builtin_huge_val:
14563	case Builtin::BI__builtin_huge_valf:
14564	case Builtin::BI__builtin_huge_vall:
14565	case Builtin::BI__builtin_huge_valf16:
14566	case Builtin::BI__builtin_huge_valf128:
14567	case Builtin::BI__builtin_inf:
14568	case Builtin::BI__builtin_inff:
14569	case Builtin::BI__builtin_infl:
14570	case Builtin::BI__builtin_inff16:
14571	case Builtin::BI__builtin_inff128: {
14572	const llvm::fltSemantics &Sem =
14573	Info.Ctx.getFloatTypeSemantics(T: E->getType());
14574	Result = llvm::APFloat::getInf(Sem);
14575	return true;
14576	}
14577
14578	case Builtin::BI__builtin_nans:
14579	case Builtin::BI__builtin_nansf:
14580	case Builtin::BI__builtin_nansl:
14581	case Builtin::BI__builtin_nansf16:
14582	case Builtin::BI__builtin_nansf128:
14583	if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(Arg: 0),
14584	true, Result))
14585	return Error(E);
14586	return true;
14587
14588	case Builtin::BI__builtin_nan:
14589	case Builtin::BI__builtin_nanf:
14590	case Builtin::BI__builtin_nanl:
14591	case Builtin::BI__builtin_nanf16:
14592	case Builtin::BI__builtin_nanf128:
14593	// If this is __builtin_nan() turn this into a nan, otherwise we
14594	// can't constant fold it.
14595	if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(Arg: 0),
14596	false, Result))
14597	return Error(E);
14598	return true;
14599
14600	case Builtin::BI__builtin_fabs:
14601	case Builtin::BI__builtin_fabsf:
14602	case Builtin::BI__builtin_fabsl:
14603	case Builtin::BI__builtin_fabsf128:
14604	// The C standard says "fabs raises no floating-point exceptions,
14605	// even if x is a signaling NaN. The returned value is independent of
14606	// the current rounding direction mode." Therefore constant folding can
14607	// proceed without regard to the floating point settings.
14608	// Reference, WG14 N2478 F.10.4.3
14609	if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info))
14610	return false;
14611
14612	if (Result.isNegative())
14613	Result.changeSign();
14614	return true;
14615
14616	case Builtin::BI__arithmetic_fence:
14617	return EvaluateFloat(E: E->getArg(Arg: 0), Result, Info);
14618
14619	// FIXME: Builtin::BI__builtin_powi
14620	// FIXME: Builtin::BI__builtin_powif
14621	// FIXME: Builtin::BI__builtin_powil
14622
14623	case Builtin::BI__builtin_copysign:
14624	case Builtin::BI__builtin_copysignf:
14625	case Builtin::BI__builtin_copysignl:
14626	case Builtin::BI__builtin_copysignf128: {
14627	APFloat RHS(0.);
14628	if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
14629	!EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
14630	return false;
14631	Result.copySign(RHS);
14632	return true;
14633	}
14634
14635	case Builtin::BI__builtin_fmax:
14636	case Builtin::BI__builtin_fmaxf:
14637	case Builtin::BI__builtin_fmaxl:
14638	case Builtin::BI__builtin_fmaxf16:
14639	case Builtin::BI__builtin_fmaxf128: {
14640	// TODO: Handle sNaN.
14641	APFloat RHS(0.);
14642	if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
14643	!EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
14644	return false;
14645	// When comparing zeroes, return +0.0 if one of the zeroes is positive.
14646	if (Result.isZero() && RHS.isZero() && Result.isNegative())
14647	Result = RHS;
14648	else if (Result.isNaN() || RHS > Result)
14649	Result = RHS;
14650	return true;
14651	}
14652
14653	case Builtin::BI__builtin_fmin:
14654	case Builtin::BI__builtin_fminf:
14655	case Builtin::BI__builtin_fminl:
14656	case Builtin::BI__builtin_fminf16:
14657	case Builtin::BI__builtin_fminf128: {
14658	// TODO: Handle sNaN.
14659	APFloat RHS(0.);
14660	if (!EvaluateFloat(E: E->getArg(Arg: 0), Result, Info) ||
14661	!EvaluateFloat(E: E->getArg(Arg: 1), Result&: RHS, Info))
14662	return false;
14663	// When comparing zeroes, return -0.0 if one of the zeroes is negative.
14664	if (Result.isZero() && RHS.isZero() && RHS.isNegative())
14665	Result = RHS;
14666	else if (Result.isNaN() || RHS < Result)
14667	Result = RHS;
14668	return true;
14669	}
14670	}
14671	}
14672
14673	bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
14674	if (E->getSubExpr()->getType()->isAnyComplexType()) {
14675	ComplexValue CV;
14676	if (!EvaluateComplex(E: E->getSubExpr(), Res&: CV, Info))
14677	return false;
14678	Result = CV.FloatReal;
14679	return true;
14680	}
14681
14682	return Visit(E->getSubExpr());
14683	}
14684
14685	bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
14686	if (E->getSubExpr()->getType()->isAnyComplexType()) {
14687	ComplexValue CV;
14688	if (!EvaluateComplex(E: E->getSubExpr(), Res&: CV, Info))
14689	return false;
14690	Result = CV.FloatImag;
14691	return true;
14692	}
14693
14694	VisitIgnoredValue(E: E->getSubExpr());
14695	const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(T: E->getType());
14696	Result = llvm::APFloat::getZero(Sem);
14697	return true;
14698	}
14699
14700	bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
14701	switch (E->getOpcode()) {
14702	default: return Error(E);
14703	case UO_Plus:
14704	return EvaluateFloat(E: E->getSubExpr(), Result, Info);
14705	case UO_Minus:
14706	// In C standard, WG14 N2478 F.3 p4
14707	// "the unary - raises no floating point exceptions,
14708	// even if the operand is signalling."
14709	if (!EvaluateFloat(E: E->getSubExpr(), Result, Info))
14710	return false;
14711	Result.changeSign();
14712	return true;
14713	}
14714	}
14715
14716	bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
14717	if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
14718	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14719
14720	APFloat RHS(0.0);
14721	bool LHSOK = EvaluateFloat(E: E->getLHS(), Result, Info);
14722	if (!LHSOK && !Info.noteFailure())
14723	return false;
14724	return EvaluateFloat(E: E->getRHS(), Result&: RHS, Info) && LHSOK &&
14725	handleFloatFloatBinOp(Info, E, LHS&: Result, Opcode: E->getOpcode(), RHS);
14726	}
14727
14728	bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
14729	Result = E->getValue();
14730	return true;
14731	}
14732
14733	bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
14734	const Expr* SubExpr = E->getSubExpr();
14735
14736	switch (E->getCastKind()) {
14737	default:
14738	return ExprEvaluatorBaseTy::VisitCastExpr(E);
14739
14740	case CK_IntegralToFloating: {
14741	APSInt IntResult;
14742	const FPOptions FPO = E->getFPFeaturesInEffect(
14743	LO: Info.Ctx.getLangOpts());
14744	return EvaluateInteger(E: SubExpr, Result&: IntResult, Info) &&
14745	HandleIntToFloatCast(Info, E, FPO, SubExpr->getType(),
14746	IntResult, E->getType(), Result);
14747	}
14748
14749	case CK_FixedPointToFloating: {
14750	APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(Ty: SubExpr->getType()));
14751	if (!EvaluateFixedPoint(E: SubExpr, Result&: FixResult, Info))
14752	return false;
14753	Result =
14754	FixResult.convertToFloat(FloatSema: Info.Ctx.getFloatTypeSemantics(T: E->getType()));
14755	return true;
14756	}
14757
14758	case CK_FloatingCast: {
14759	if (!Visit(SubExpr))
14760	return false;
14761	return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
14762	Result);
14763	}
14764
14765	case CK_FloatingComplexToReal: {
14766	ComplexValue V;
14767	if (!EvaluateComplex(E: SubExpr, Res&: V, Info))
14768	return false;
14769	Result = V.getComplexFloatReal();
14770	return true;
14771	}
14772	}
14773	}
14774
14775	//===----------------------------------------------------------------------===//
14776	// Complex Evaluation (for float and integer)
14777	//===----------------------------------------------------------------------===//
14778
14779	namespace {
14780	class ComplexExprEvaluator
14781	: public ExprEvaluatorBase<ComplexExprEvaluator> {
14782	ComplexValue &Result;
14783
14784	public:
14785	ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
14786	: ExprEvaluatorBaseTy(info), Result(Result) {}
14787
14788	bool Success(const APValue &V, const Expr *e) {
14789	Result.setFrom(V);
14790	return true;
14791	}
14792
14793	bool ZeroInitialization(const Expr *E);
14794
14795	//===--------------------------------------------------------------------===//
14796	// Visitor Methods
14797	//===--------------------------------------------------------------------===//
14798
14799	bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
14800	bool VisitCastExpr(const CastExpr *E);
14801	bool VisitBinaryOperator(const BinaryOperator *E);
14802	bool VisitUnaryOperator(const UnaryOperator *E);
14803	bool VisitInitListExpr(const InitListExpr *E);
14804	bool VisitCallExpr(const CallExpr *E);
14805	};
14806	} // end anonymous namespace
14807
14808	static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
14809	EvalInfo &Info) {
14810	assert(!E->isValueDependent());
14811	assert(E->isPRValue() && E->getType()->isAnyComplexType());
14812	return ComplexExprEvaluator(Info, Result).Visit(E);
14813	}
14814
14815	bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
14816	QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
14817	if (ElemTy->isRealFloatingType()) {
14818	Result.makeComplexFloat();
14819	APFloat Zero = APFloat::getZero(Sem: Info.Ctx.getFloatTypeSemantics(T: ElemTy));
14820	Result.FloatReal = Zero;
14821	Result.FloatImag = Zero;
14822	} else {
14823	Result.makeComplexInt();
14824	APSInt Zero = Info.Ctx.MakeIntValue(Value: 0, Type: ElemTy);
14825	Result.IntReal = Zero;
14826	Result.IntImag = Zero;
14827	}
14828	return true;
14829	}
14830
14831	bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
14832	const Expr* SubExpr = E->getSubExpr();
14833
14834	if (SubExpr->getType()->isRealFloatingType()) {
14835	Result.makeComplexFloat();
14836	APFloat &Imag = Result.FloatImag;
14837	if (!EvaluateFloat(E: SubExpr, Result&: Imag, Info))
14838	return false;
14839
14840	Result.FloatReal = APFloat(Imag.getSemantics());
14841	return true;
14842	} else {
14843	assert(SubExpr->getType()->isIntegerType() &&
14844	"Unexpected imaginary literal.");
14845
14846	Result.makeComplexInt();
14847	APSInt &Imag = Result.IntImag;
14848	if (!EvaluateInteger(E: SubExpr, Result&: Imag, Info))
14849	return false;
14850
14851	Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
14852	return true;
14853	}
14854	}
14855
14856	bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
14857
14858	switch (E->getCastKind()) {
14859	case CK_BitCast:
14860	case CK_BaseToDerived:
14861	case CK_DerivedToBase:
14862	case CK_UncheckedDerivedToBase:
14863	case CK_Dynamic:
14864	case CK_ToUnion:
14865	case CK_ArrayToPointerDecay:
14866	case CK_FunctionToPointerDecay:
14867	case CK_NullToPointer:
14868	case CK_NullToMemberPointer:
14869	case CK_BaseToDerivedMemberPointer:
14870	case CK_DerivedToBaseMemberPointer:
14871	case CK_MemberPointerToBoolean:
14872	case CK_ReinterpretMemberPointer:
14873	case CK_ConstructorConversion:
14874	case CK_IntegralToPointer:
14875	case CK_PointerToIntegral:
14876	case CK_PointerToBoolean:
14877	case CK_ToVoid:
14878	case CK_VectorSplat:
14879	case CK_IntegralCast:
14880	case CK_BooleanToSignedIntegral:
14881	case CK_IntegralToBoolean:
14882	case CK_IntegralToFloating:
14883	case CK_FloatingToIntegral:
14884	case CK_FloatingToBoolean:
14885	case CK_FloatingCast:
14886	case CK_CPointerToObjCPointerCast:
14887	case CK_BlockPointerToObjCPointerCast:
14888	case CK_AnyPointerToBlockPointerCast:
14889	case CK_ObjCObjectLValueCast:
14890	case CK_FloatingComplexToReal:
14891	case CK_FloatingComplexToBoolean:
14892	case CK_IntegralComplexToReal:
14893	case CK_IntegralComplexToBoolean:
14894	case CK_ARCProduceObject:
14895	case CK_ARCConsumeObject:
14896	case CK_ARCReclaimReturnedObject:
14897	case CK_ARCExtendBlockObject:
14898	case CK_CopyAndAutoreleaseBlockObject:
14899	case CK_BuiltinFnToFnPtr:
14900	case CK_ZeroToOCLOpaqueType:
14901	case CK_NonAtomicToAtomic:
14902	case CK_AddressSpaceConversion:
14903	case CK_IntToOCLSampler:
14904	case CK_FloatingToFixedPoint:
14905	case CK_FixedPointToFloating:
14906	case CK_FixedPointCast:
14907	case CK_FixedPointToBoolean:
14908	case CK_FixedPointToIntegral:
14909	case CK_IntegralToFixedPoint:
14910	case CK_MatrixCast:
14911	case CK_HLSLVectorTruncation:
14912	llvm_unreachable("invalid cast kind for complex value");
14913
14914	case CK_LValueToRValue:
14915	case CK_AtomicToNonAtomic:
14916	case CK_NoOp:
14917	case CK_LValueToRValueBitCast:
14918	case CK_HLSLArrayRValue:
14919	return ExprEvaluatorBaseTy::VisitCastExpr(E);
14920
14921	case CK_Dependent:
14922	case CK_LValueBitCast:
14923	case CK_UserDefinedConversion:
14924	return Error(E);
14925
14926	case CK_FloatingRealToComplex: {
14927	APFloat &Real = Result.FloatReal;
14928	if (!EvaluateFloat(E: E->getSubExpr(), Result&: Real, Info))
14929	return false;
14930
14931	Result.makeComplexFloat();
14932	Result.FloatImag = APFloat(Real.getSemantics());
14933	return true;
14934	}
14935
14936	case CK_FloatingComplexCast: {
14937	if (!Visit(E->getSubExpr()))
14938	return false;
14939
14940	QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14941	QualType From
14942	= E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14943
14944	return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
14945	HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
14946	}
14947
14948	case CK_FloatingComplexToIntegralComplex: {
14949	if (!Visit(E->getSubExpr()))
14950	return false;
14951
14952	QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14953	QualType From
14954	= E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14955	Result.makeComplexInt();
14956	return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
14957	To, Result.IntReal) &&
14958	HandleFloatToIntCast(Info, E, From, Result.FloatImag,
14959	To, Result.IntImag);
14960	}
14961
14962	case CK_IntegralRealToComplex: {
14963	APSInt &Real = Result.IntReal;
14964	if (!EvaluateInteger(E: E->getSubExpr(), Result&: Real, Info))
14965	return false;
14966
14967	Result.makeComplexInt();
14968	Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
14969	return true;
14970	}
14971
14972	case CK_IntegralComplexCast: {
14973	if (!Visit(E->getSubExpr()))
14974	return false;
14975
14976	QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14977	QualType From
14978	= E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14979
14980	Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
14981	Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
14982	return true;
14983	}
14984
14985	case CK_IntegralComplexToFloatingComplex: {
14986	if (!Visit(E->getSubExpr()))
14987	return false;
14988
14989	const FPOptions FPO = E->getFPFeaturesInEffect(
14990	LO: Info.Ctx.getLangOpts());
14991	QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14992	QualType From
14993	= E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14994	Result.makeComplexFloat();
14995	return HandleIntToFloatCast(Info, E, FPO, From, Result.IntReal,
14996	To, Result.FloatReal) &&
14997	HandleIntToFloatCast(Info, E, FPO, From, Result.IntImag,
14998	To, Result.FloatImag);
14999	}
15000	}
15001
15002	llvm_unreachable("unknown cast resulting in complex value");
15003	}
15004
15005	bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
15006	if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
15007	return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
15008
15009	// Track whether the LHS or RHS is real at the type system level. When this is
15010	// the case we can simplify our evaluation strategy.
15011	bool LHSReal = false, RHSReal = false;
15012
15013	bool LHSOK;
15014	if (E->getLHS()->getType()->isRealFloatingType()) {
15015	LHSReal = true;
15016	APFloat &Real = Result.FloatReal;
15017	LHSOK = EvaluateFloat(E: E->getLHS(), Result&: Real, Info);
15018	if (LHSOK) {
15019	Result.makeComplexFloat();
15020	Result.FloatImag = APFloat(Real.getSemantics());
15021	}
15022	} else {
15023	LHSOK = Visit(E->getLHS());
15024	}
15025	if (!LHSOK && !Info.noteFailure())
15026	return false;
15027
15028	ComplexValue RHS;
15029	if (E->getRHS()->getType()->isRealFloatingType()) {
15030	RHSReal = true;
15031	APFloat &Real = RHS.FloatReal;
15032	if (!EvaluateFloat(E: E->getRHS(), Result&: Real, Info) || !LHSOK)
15033	return false;
15034	RHS.makeComplexFloat();
15035	RHS.FloatImag = APFloat(Real.getSemantics());
15036	} else if (!EvaluateComplex(E: E->getRHS(), Result&: RHS, Info) || !LHSOK)
15037	return false;
15038
15039	assert(!(LHSReal && RHSReal) &&
15040	"Cannot have both operands of a complex operation be real.");
15041	switch (E->getOpcode()) {
15042	default: return Error(E);
15043	case BO_Add:
15044	if (Result.isComplexFloat()) {
15045	Result.getComplexFloatReal().add(RHS: RHS.getComplexFloatReal(),
15046	RM: APFloat::rmNearestTiesToEven);
15047	if (LHSReal)
15048	Result.getComplexFloatImag() = RHS.getComplexFloatImag();
15049	else if (!RHSReal)
15050	Result.getComplexFloatImag().add(RHS: RHS.getComplexFloatImag(),
15051	RM: APFloat::rmNearestTiesToEven);
15052	} else {
15053	Result.getComplexIntReal() += RHS.getComplexIntReal();
15054	Result.getComplexIntImag() += RHS.getComplexIntImag();
15055	}
15056	break;
15057	case BO_Sub:
15058	if (Result.isComplexFloat()) {
15059	Result.getComplexFloatReal().subtract(RHS: RHS.getComplexFloatReal(),
15060	RM: APFloat::rmNearestTiesToEven);
15061	if (LHSReal) {
15062	Result.getComplexFloatImag() = RHS.getComplexFloatImag();
15063	Result.getComplexFloatImag().changeSign();
15064	} else if (!RHSReal) {
15065	Result.getComplexFloatImag().subtract(RHS: RHS.getComplexFloatImag(),
15066	RM: APFloat::rmNearestTiesToEven);
15067	}
15068	} else {
15069	Result.getComplexIntReal() -= RHS.getComplexIntReal();
15070	Result.getComplexIntImag() -= RHS.getComplexIntImag();
15071	}
15072	break;
15073	case BO_Mul:
15074	if (Result.isComplexFloat()) {
15075	// This is an implementation of complex multiplication according to the
15076	// constraints laid out in C11 Annex G. The implementation uses the
15077	// following naming scheme:
15078	// (a + ib) * (c + id)
15079	ComplexValue LHS = Result;
15080	APFloat &A = LHS.getComplexFloatReal();
15081	APFloat &B = LHS.getComplexFloatImag();
15082	APFloat &C = RHS.getComplexFloatReal();
15083	APFloat &D = RHS.getComplexFloatImag();
15084	APFloat &ResR = Result.getComplexFloatReal();
15085	APFloat &ResI = Result.getComplexFloatImag();
15086	if (LHSReal) {
15087	assert(!RHSReal && "Cannot have two real operands for a complex op!");
15088	ResR = A * C;
15089	ResI = A * D;
15090	} else if (RHSReal) {
15091	ResR = C * A;
15092	ResI = C * B;
15093	} else {
15094	// In the fully general case, we need to handle NaNs and infinities
15095	// robustly.
15096	APFloat AC = A * C;
15097	APFloat BD = B * D;
15098	APFloat AD = A * D;
15099	APFloat BC = B * C;
15100	ResR = AC - BD;
15101	ResI = AD + BC;
15102	if (ResR.isNaN() && ResI.isNaN()) {
15103	bool Recalc = false;
15104	if (A.isInfinity() || B.isInfinity()) {
15105	A = APFloat::copySign(
15106	Value: APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), Sign: A);
15107	B = APFloat::copySign(
15108	Value: APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), Sign: B);
15109	if (C.isNaN())
15110	C = APFloat::copySign(Value: APFloat(C.getSemantics()), Sign: C);
15111	if (D.isNaN())
15112	D = APFloat::copySign(Value: APFloat(D.getSemantics()), Sign: D);
15113	Recalc = true;
15114	}
15115	if (C.isInfinity() || D.isInfinity()) {
15116	C = APFloat::copySign(
15117	Value: APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), Sign: C);
15118	D = APFloat::copySign(
15119	Value: APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), Sign: D);
15120	if (A.isNaN())
15121	A = APFloat::copySign(Value: APFloat(A.getSemantics()), Sign: A);
15122	if (B.isNaN())
15123	B = APFloat::copySign(Value: APFloat(B.getSemantics()), Sign: B);
15124	Recalc = true;
15125	}
15126	if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
15127	AD.isInfinity() || BC.isInfinity())) {
15128	if (A.isNaN())
15129	A = APFloat::copySign(Value: APFloat(A.getSemantics()), Sign: A);
15130	if (B.isNaN())
15131	B = APFloat::copySign(Value: APFloat(B.getSemantics()), Sign: B);
15132	if (C.isNaN())
15133	C = APFloat::copySign(Value: APFloat(C.getSemantics()), Sign: C);
15134	if (D.isNaN())
15135	D = APFloat::copySign(Value: APFloat(D.getSemantics()), Sign: D);
15136	Recalc = true;
15137	}
15138	if (Recalc) {
15139	ResR = APFloat::getInf(Sem: A.getSemantics()) * (A * C - B * D);
15140	ResI = APFloat::getInf(Sem: A.getSemantics()) * (A * D + B * C);
15141	}
15142	}
15143	}
15144	} else {
15145	ComplexValue LHS = Result;
15146	Result.getComplexIntReal() =
15147	(LHS.getComplexIntReal() * RHS.getComplexIntReal() -
15148	LHS.getComplexIntImag() * RHS.getComplexIntImag());
15149	Result.getComplexIntImag() =
15150	(LHS.getComplexIntReal() * RHS.getComplexIntImag() +
15151	LHS.getComplexIntImag() * RHS.getComplexIntReal());
15152	}
15153	break;
15154	case BO_Div:
15155	if (Result.isComplexFloat()) {
15156	// This is an implementation of complex division according to the
15157	// constraints laid out in C11 Annex G. The implementation uses the
15158	// following naming scheme:
15159	// (a + ib) / (c + id)
15160	ComplexValue LHS = Result;
15161	APFloat &A = LHS.getComplexFloatReal();
15162	APFloat &B = LHS.getComplexFloatImag();
15163	APFloat &C = RHS.getComplexFloatReal();
15164	APFloat &D = RHS.getComplexFloatImag();
15165	APFloat &ResR = Result.getComplexFloatReal();
15166	APFloat &ResI = Result.getComplexFloatImag();
15167	if (RHSReal) {
15168	ResR = A / C;
15169	ResI = B / C;
15170	} else {
15171	if (LHSReal) {
15172	// No real optimizations we can do here, stub out with zero.
15173	B = APFloat::getZero(Sem: A.getSemantics());
15174	}
15175	int DenomLogB = 0;
15176	APFloat MaxCD = maxnum(A: abs(X: C), B: abs(X: D));
15177	if (MaxCD.isFinite()) {
15178	DenomLogB = ilogb(Arg: MaxCD);
15179	C = scalbn(X: C, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
15180	D = scalbn(X: D, Exp: -DenomLogB, RM: APFloat::rmNearestTiesToEven);
15181	}
15182	APFloat Denom = C * C + D * D;
15183	ResR = scalbn(X: (A * C + B * D) / Denom, Exp: -DenomLogB,
15184	RM: APFloat::rmNearestTiesToEven);
15185	ResI = scalbn(X: (B * C - A * D) / Denom, Exp: -DenomLogB,
15186	RM: APFloat::rmNearestTiesToEven);
15187	if (ResR.isNaN() && ResI.isNaN()) {
15188	if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
15189	ResR = APFloat::getInf(Sem: ResR.getSemantics(), Negative: C.isNegative()) * A;
15190	ResI = APFloat::getInf(Sem: ResR.getSemantics(), Negative: C.isNegative()) * B;
15191	} else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
15192	D.isFinite()) {
15193	A = APFloat::copySign(
15194	Value: APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), Sign: A);
15195	B = APFloat::copySign(
15196	Value: APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), Sign: B);
15197	ResR = APFloat::getInf(Sem: ResR.getSemantics()) * (A * C + B * D);
15198	ResI = APFloat::getInf(Sem: ResI.getSemantics()) * (B * C - A * D);
15199	} else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
15200	C = APFloat::copySign(
15201	Value: APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), Sign: C);
15202	D = APFloat::copySign(
15203	Value: APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), Sign: D);
15204	ResR = APFloat::getZero(Sem: ResR.getSemantics()) * (A * C + B * D);
15205	ResI = APFloat::getZero(Sem: ResI.getSemantics()) * (B * C - A * D);
15206	}
15207	}
15208	}
15209	} else {
15210	if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
15211	return Error(E, diag::note_expr_divide_by_zero);
15212
15213	ComplexValue LHS = Result;
15214	APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
15215	RHS.getComplexIntImag() * RHS.getComplexIntImag();
15216	Result.getComplexIntReal() =
15217	(LHS.getComplexIntReal() * RHS.getComplexIntReal() +
15218	LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
15219	Result.getComplexIntImag() =
15220	(LHS.getComplexIntImag() * RHS.getComplexIntReal() -
15221	LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
15222	}
15223	break;
15224	}
15225
15226	return true;
15227	}
15228
15229	bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
15230	// Get the operand value into 'Result'.
15231	if (!Visit(E->getSubExpr()))
15232	return false;
15233
15234	switch (E->getOpcode()) {
15235	default:
15236	return Error(E);
15237	case UO_Extension:
15238	return true;
15239	case UO_Plus:
15240	// The result is always just the subexpr.
15241	return true;
15242	case UO_Minus:
15243	if (Result.isComplexFloat()) {
15244	Result.getComplexFloatReal().changeSign();
15245	Result.getComplexFloatImag().changeSign();
15246	}
15247	else {
15248	Result.getComplexIntReal() = -Result.getComplexIntReal();
15249	Result.getComplexIntImag() = -Result.getComplexIntImag();
15250	}
15251	return true;
15252	case UO_Not:
15253	if (Result.isComplexFloat())
15254	Result.getComplexFloatImag().changeSign();
15255	else
15256	Result.getComplexIntImag() = -Result.getComplexIntImag();
15257	return true;
15258	}
15259	}
15260
15261	bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
15262	if (E->getNumInits() == 2) {
15263	if (E->getType()->isComplexType()) {
15264	Result.makeComplexFloat();
15265	if (!EvaluateFloat(E: E->getInit(Init: 0), Result&: Result.FloatReal, Info))
15266	return false;
15267	if (!EvaluateFloat(E: E->getInit(Init: 1), Result&: Result.FloatImag, Info))
15268	return false;
15269	} else {
15270	Result.makeComplexInt();
15271	if (!EvaluateInteger(E: E->getInit(Init: 0), Result&: Result.IntReal, Info))
15272	return false;
15273	if (!EvaluateInteger(E: E->getInit(Init: 1), Result&: Result.IntImag, Info))
15274	return false;
15275	}
15276	return true;
15277	}
15278	return ExprEvaluatorBaseTy::VisitInitListExpr(E);
15279	}
15280
15281	bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) {
15282	if (!IsConstantEvaluatedBuiltinCall(E))
15283	return ExprEvaluatorBaseTy::VisitCallExpr(E);
15284
15285	switch (E->getBuiltinCallee()) {
15286	case Builtin::BI__builtin_complex:
15287	Result.makeComplexFloat();
15288	if (!EvaluateFloat(E: E->getArg(Arg: 0), Result&: Result.FloatReal, Info))
15289	return false;
15290	if (!EvaluateFloat(E: E->getArg(Arg: 1), Result&: Result.FloatImag, Info))
15291	return false;
15292	return true;
15293
15294	default:
15295	return false;
15296	}
15297	}
15298
15299	//===----------------------------------------------------------------------===//
15300	// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
15301	// implicit conversion.
15302	//===----------------------------------------------------------------------===//
15303
15304	namespace {
15305	class AtomicExprEvaluator :
15306	public ExprEvaluatorBase<AtomicExprEvaluator> {
15307	const LValue *This;
15308	APValue &Result;
15309	public:
15310	AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
15311	: ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
15312
15313	bool Success(const APValue &V, const Expr *E) {
15314	Result = V;
15315	return true;
15316	}
15317
15318	bool ZeroInitialization(const Expr *E) {
15319	ImplicitValueInitExpr VIE(
15320	E->getType()->castAs<AtomicType>()->getValueType());
15321	// For atomic-qualified class (and array) types in C++, initialize the
15322	// _Atomic-wrapped subobject directly, in-place.
15323	return This ? EvaluateInPlace(Result, Info, *This, &VIE)
15324	: Evaluate(Result, Info, &VIE);
15325	}
15326
15327	bool VisitCastExpr(const CastExpr *E) {
15328	switch (E->getCastKind()) {
15329	default:
15330	return ExprEvaluatorBaseTy::VisitCastExpr(E);
15331	case CK_NullToPointer:
15332	VisitIgnoredValue(E: E->getSubExpr());
15333	return ZeroInitialization(E);
15334	case CK_NonAtomicToAtomic:
15335	return This ? EvaluateInPlace(Result, Info, This: *This, E: E->getSubExpr())
15336	: Evaluate(Result, Info, E: E->getSubExpr());
15337	}
15338	}
15339	};
15340	} // end anonymous namespace
15341
15342	static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
15343	EvalInfo &Info) {
15344	assert(!E->isValueDependent());
15345	assert(E->isPRValue() && E->getType()->isAtomicType());
15346	return AtomicExprEvaluator(Info, This, Result).Visit(E);
15347	}
15348
15349	//===----------------------------------------------------------------------===//
15350	// Void expression evaluation, primarily for a cast to void on the LHS of a
15351	// comma operator
15352	//===----------------------------------------------------------------------===//
15353
15354	namespace {
15355	class VoidExprEvaluator
15356	: public ExprEvaluatorBase<VoidExprEvaluator> {
15357	public:
15358	VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
15359
15360	bool Success(const APValue &V, const Expr *e) { return true; }
15361
15362	bool ZeroInitialization(const Expr *E) { return true; }
15363
15364	bool VisitCastExpr(const CastExpr *E) {
15365	switch (E->getCastKind()) {
15366	default:
15367	return ExprEvaluatorBaseTy::VisitCastExpr(E);
15368	case CK_ToVoid:
15369	VisitIgnoredValue(E: E->getSubExpr());
15370	return true;
15371	}
15372	}
15373
15374	bool VisitCallExpr(const CallExpr *E) {
15375	if (!IsConstantEvaluatedBuiltinCall(E))
15376	return ExprEvaluatorBaseTy::VisitCallExpr(E);
15377
15378	switch (E->getBuiltinCallee()) {
15379	case Builtin::BI__assume:
15380	case Builtin::BI__builtin_assume:
15381	// The argument is not evaluated!
15382	return true;
15383
15384	case Builtin::BI__builtin_operator_delete:
15385	return HandleOperatorDeleteCall(Info, E);
15386
15387	default:
15388	return false;
15389	}
15390	}
15391
15392	bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
15393	};
15394	} // end anonymous namespace
15395
15396	bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
15397	// We cannot speculatively evaluate a delete expression.
15398	if (Info.SpeculativeEvaluationDepth)
15399	return false;
15400
15401	FunctionDecl *OperatorDelete = E->getOperatorDelete();
15402	if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) {
15403	Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
15404	<< isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete;
15405	return false;
15406	}
15407
15408	const Expr *Arg = E->getArgument();
15409
15410	LValue Pointer;
15411	if (!EvaluatePointer(E: Arg, Result&: Pointer, Info))
15412	return false;
15413	if (Pointer.Designator.Invalid)
15414	return false;
15415
15416	// Deleting a null pointer has no effect.
15417	if (Pointer.isNullPointer()) {
15418	// This is the only case where we need to produce an extension warning:
15419	// the only other way we can succeed is if we find a dynamic allocation,
15420	// and we will have warned when we allocated it in that case.
15421	if (!Info.getLangOpts().CPlusPlus20)
15422	Info.CCEDiag(E, diag::note_constexpr_new);
15423	return true;
15424	}
15425
15426	std::optional<DynAlloc *> Alloc = CheckDeleteKind(
15427	Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
15428	if (!Alloc)
15429	return false;
15430	QualType AllocType = Pointer.Base.getDynamicAllocType();
15431
15432	// For the non-array case, the designator must be empty if the static type
15433	// does not have a virtual destructor.
15434	if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
15435	!hasVirtualDestructor(T: Arg->getType()->getPointeeType())) {
15436	Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor)
15437	<< Arg->getType()->getPointeeType() << AllocType;
15438	return false;
15439	}
15440
15441	// For a class type with a virtual destructor, the selected operator delete
15442	// is the one looked up when building the destructor.
15443	if (!E->isArrayForm() && !E->isGlobalDelete()) {
15444	const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(T: AllocType);
15445	if (VirtualDelete &&
15446	!VirtualDelete->isReplaceableGlobalAllocationFunction()) {
15447	Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
15448	<< isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete;
15449	return false;
15450	}
15451	}
15452
15453	if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(),
15454	(*Alloc)->Value, AllocType))
15455	return false;
15456
15457	if (!Info.HeapAllocs.erase(x: Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
15458	// The element was already erased. This means the destructor call also
15459	// deleted the object.
15460	// FIXME: This probably results in undefined behavior before we get this
15461	// far, and should be diagnosed elsewhere first.
15462	Info.FFDiag(E, diag::note_constexpr_double_delete);
15463	return false;
15464	}
15465
15466	return true;
15467	}
15468
15469	static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
15470	assert(!E->isValueDependent());
15471	assert(E->isPRValue() && E->getType()->isVoidType());
15472	return VoidExprEvaluator(Info).Visit(E);
15473	}
15474
15475	//===----------------------------------------------------------------------===//
15476	// Top level Expr::EvaluateAsRValue method.
15477	//===----------------------------------------------------------------------===//
15478
15479	static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
15480	assert(!E->isValueDependent());
15481	// In C, function designators are not lvalues, but we evaluate them as if they
15482	// are.
15483	QualType T = E->getType();
15484	if (E->isGLValue() || T->isFunctionType()) {
15485	LValue LV;
15486	if (!EvaluateLValue(E, Result&: LV, Info))
15487	return false;
15488	LV.moveInto(V&: Result);
15489	} else if (T->isVectorType()) {
15490	if (!EvaluateVector(E, Result, Info))
15491	return false;
15492	} else if (T->isIntegralOrEnumerationType()) {
15493	if (!IntExprEvaluator(Info, Result).Visit(E))
15494	return false;
15495	} else if (T->hasPointerRepresentation()) {
15496	LValue LV;
15497	if (!EvaluatePointer(E, Result&: LV, Info))
15498	return false;
15499	LV.moveInto(V&: Result);
15500	} else if (T->isRealFloatingType()) {
15501	llvm::APFloat F(0.0);
15502	if (!EvaluateFloat(E, Result&: F, Info))
15503	return false;
15504	Result = APValue(F);
15505	} else if (T->isAnyComplexType()) {
15506	ComplexValue C;
15507	if (!EvaluateComplex(E, Result&: C, Info))
15508	return false;
15509	C.moveInto(v&: Result);
15510	} else if (T->isFixedPointType()) {
15511	if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false;
15512	} else if (T->isMemberPointerType()) {
15513	MemberPtr P;
15514	if (!EvaluateMemberPointer(E, Result&: P, Info))
15515	return false;
15516	P.moveInto(V&: Result);
15517	return true;
15518	} else if (T->isArrayType()) {
15519	LValue LV;
15520	APValue &Value =
15521	Info.CurrentCall->createTemporary(Key: E, T, Scope: ScopeKind::FullExpression, LV);
15522	if (!EvaluateArray(E, This: LV, Result&: Value, Info))
15523	return false;
15524	Result = Value;
15525	} else if (T->isRecordType()) {
15526	LValue LV;
15527	APValue &Value =
15528	Info.CurrentCall->createTemporary(Key: E, T, Scope: ScopeKind::FullExpression, LV);
15529	if (!EvaluateRecord(E, This: LV, Result&: Value, Info))
15530	return false;
15531	Result = Value;
15532	} else if (T->isVoidType()) {
15533	if (!Info.getLangOpts().CPlusPlus11)
15534	Info.CCEDiag(E, diag::note_constexpr_nonliteral)
15535	<< E->getType();
15536	if (!EvaluateVoid(E, Info))
15537	return false;
15538	} else if (T->isAtomicType()) {
15539	QualType Unqual = T.getAtomicUnqualifiedType();
15540	if (Unqual->isArrayType() || Unqual->isRecordType()) {
15541	LValue LV;
15542	APValue &Value = Info.CurrentCall->createTemporary(
15543	Key: E, T: Unqual, Scope: ScopeKind::FullExpression, LV);
15544	if (!EvaluateAtomic(E, This: &LV, Result&: Value, Info))
15545	return false;
15546	Result = Value;
15547	} else {
15548	if (!EvaluateAtomic(E, This: nullptr, Result, Info))
15549	return false;
15550	}
15551	} else if (Info.getLangOpts().CPlusPlus11) {
15552	Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
15553	return false;
15554	} else {
15555	Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
15556	return false;
15557	}
15558
15559	return true;
15560	}
15561
15562	/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
15563	/// cases, the in-place evaluation is essential, since later initializers for
15564	/// an object can indirectly refer to subobjects which were initialized earlier.
15565	static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
15566	const Expr *E, bool AllowNonLiteralTypes) {
15567	assert(!E->isValueDependent());
15568
15569	if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, This: &This))
15570	return false;
15571
15572	if (E->isPRValue()) {
15573	// Evaluate arrays and record types in-place, so that later initializers can
15574	// refer to earlier-initialized members of the object.
15575	QualType T = E->getType();
15576	if (T->isArrayType())
15577	return EvaluateArray(E, This, Result, Info);
15578	else if (T->isRecordType())
15579	return EvaluateRecord(E, This, Result, Info);
15580	else if (T->isAtomicType()) {
15581	QualType Unqual = T.getAtomicUnqualifiedType();
15582	if (Unqual->isArrayType() || Unqual->isRecordType())
15583	return EvaluateAtomic(E, This: &This, Result, Info);
15584	}
15585	}
15586
15587	// For any other type, in-place evaluation is unimportant.
15588	return Evaluate(Result, Info, E);
15589	}
15590
15591	/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
15592	/// lvalue-to-rvalue cast if it is an lvalue.
15593	static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
15594	assert(!E->isValueDependent());
15595
15596	if (E->getType().isNull())
15597	return false;
15598
15599	if (!CheckLiteralType(Info, E))
15600	return false;
15601
15602	if (Info.EnableNewConstInterp) {
15603	if (!Info.Ctx.getInterpContext().evaluateAsRValue(Parent&: Info, E, Result))
15604	return false;
15605	return CheckConstantExpression(Info, DiagLoc: E->getExprLoc(), Type: E->getType(), Value: Result,
15606	Kind: ConstantExprKind::Normal);
15607	}
15608
15609	if (!::Evaluate(Result, Info, E))
15610	return false;
15611
15612	// Implicit lvalue-to-rvalue cast.
15613	if (E->isGLValue()) {
15614	LValue LV;
15615	LV.setFrom(Ctx&: Info.Ctx, V: Result);
15616	if (!handleLValueToRValueConversion(Info, Conv: E, Type: E->getType(), LVal: LV, RVal&: Result))
15617	return false;
15618	}
15619
15620	// Check this core constant expression is a constant expression.
15621	return CheckConstantExpression(Info, DiagLoc: E->getExprLoc(), Type: E->getType(), Value: Result,
15622	Kind: ConstantExprKind::Normal) &&
15623	CheckMemoryLeaks(Info);
15624	}
15625
15626	static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
15627	const ASTContext &Ctx, bool &IsConst) {
15628	// Fast-path evaluations of integer literals, since we sometimes see files
15629	// containing vast quantities of these.
15630	if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Val: Exp)) {
15631	Result.Val = APValue(APSInt(L->getValue(),
15632	L->getType()->isUnsignedIntegerType()));
15633	IsConst = true;
15634	return true;
15635	}
15636
15637	if (const auto *L = dyn_cast<CXXBoolLiteralExpr>(Val: Exp)) {
15638	Result.Val = APValue(APSInt(APInt(1, L->getValue())));
15639	IsConst = true;
15640	return true;
15641	}
15642
15643	if (const auto *CE = dyn_cast<ConstantExpr>(Val: Exp)) {
15644	if (CE->hasAPValueResult()) {
15645	Result.Val = CE->getAPValueResult();
15646	IsConst = true;
15647	return true;
15648	}
15649
15650	// The SubExpr is usually just an IntegerLiteral.
15651	return FastEvaluateAsRValue(CE->getSubExpr(), Result, Ctx, IsConst);
15652	}
15653
15654	// This case should be rare, but we need to check it before we check on
15655	// the type below.
15656	if (Exp->getType().isNull()) {
15657	IsConst = false;
15658	return true;
15659	}
15660
15661	return false;
15662	}
15663
15664	static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
15665	Expr::SideEffectsKind SEK) {
15666	return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
15667	(SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
15668	}
15669
15670	static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
15671	const ASTContext &Ctx, EvalInfo &Info) {
15672	assert(!E->isValueDependent());
15673	bool IsConst;
15674	if (FastEvaluateAsRValue(Exp: E, Result, Ctx, IsConst))
15675	return IsConst;
15676
15677	return EvaluateAsRValue(Info, E, Result&: Result.Val);
15678	}
15679
15680	static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
15681	const ASTContext &Ctx,
15682	Expr::SideEffectsKind AllowSideEffects,
15683	EvalInfo &Info) {
15684	assert(!E->isValueDependent());
15685	if (!E->getType()->isIntegralOrEnumerationType())
15686	return false;
15687
15688	if (!::EvaluateAsRValue(E, Result&: ExprResult, Ctx, Info) ||
15689	!ExprResult.Val.isInt() ||
15690	hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
15691	return false;
15692
15693	return true;
15694	}
15695
15696	static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
15697	const ASTContext &Ctx,
15698	Expr::SideEffectsKind AllowSideEffects,
15699	EvalInfo &Info) {
15700	assert(!E->isValueDependent());
15701	if (!E->getType()->isFixedPointType())
15702	return false;
15703
15704	if (!::EvaluateAsRValue(E, Result&: ExprResult, Ctx, Info))
15705	return false;
15706
15707	if (!ExprResult.Val.isFixedPoint() ||
15708	hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
15709	return false;
15710
15711	return true;
15712	}
15713
15714	/// EvaluateAsRValue - Return true if this is a constant which we can fold using
15715	/// any crazy technique (that has nothing to do with language standards) that
15716	/// we want to. If this function returns true, it returns the folded constant
15717	/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
15718	/// will be applied to the result.
15719	bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
15720	bool InConstantContext) const {
15721	assert(!isValueDependent() &&
15722	"Expression evaluator can't be called on a dependent expression.");
15723	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsRValue");
15724	EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
15725	Info.InConstantContext = InConstantContext;
15726	return ::EvaluateAsRValue(E: this, Result, Ctx, Info);
15727	}
15728
15729	bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
15730	bool InConstantContext) const {
15731	assert(!isValueDependent() &&
15732	"Expression evaluator can't be called on a dependent expression.");
15733	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsBooleanCondition");
15734	EvalResult Scratch;
15735	return EvaluateAsRValue(Result&: Scratch, Ctx, InConstantContext) &&
15736	HandleConversionToBool(Val: Scratch.Val, Result);
15737	}
15738
15739	bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
15740	SideEffectsKind AllowSideEffects,
15741	bool InConstantContext) const {
15742	assert(!isValueDependent() &&
15743	"Expression evaluator can't be called on a dependent expression.");
15744	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsInt");
15745	EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
15746	Info.InConstantContext = InConstantContext;
15747	return ::EvaluateAsInt(E: this, ExprResult&: Result, Ctx, AllowSideEffects, Info);
15748	}
15749
15750	bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
15751	SideEffectsKind AllowSideEffects,
15752	bool InConstantContext) const {
15753	assert(!isValueDependent() &&
15754	"Expression evaluator can't be called on a dependent expression.");
15755	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFixedPoint");
15756	EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
15757	Info.InConstantContext = InConstantContext;
15758	return ::EvaluateAsFixedPoint(E: this, ExprResult&: Result, Ctx, AllowSideEffects, Info);
15759	}
15760
15761	bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
15762	SideEffectsKind AllowSideEffects,
15763	bool InConstantContext) const {
15764	assert(!isValueDependent() &&
15765	"Expression evaluator can't be called on a dependent expression.");
15766
15767	if (!getType()->isRealFloatingType())
15768	return false;
15769
15770	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFloat");
15771	EvalResult ExprResult;
15772	if (!EvaluateAsRValue(Result&: ExprResult, Ctx, InConstantContext) ||
15773	!ExprResult.Val.isFloat() ||
15774	hasUnacceptableSideEffect(Result&: ExprResult, SEK: AllowSideEffects))
15775	return false;
15776
15777	Result = ExprResult.Val.getFloat();
15778	return true;
15779	}
15780
15781	bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
15782	bool InConstantContext) const {
15783	assert(!isValueDependent() &&
15784	"Expression evaluator can't be called on a dependent expression.");
15785
15786	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsLValue");
15787	EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
15788	Info.InConstantContext = InConstantContext;
15789	LValue LV;
15790	CheckedTemporaries CheckedTemps;
15791	if (!EvaluateLValue(E: this, Result&: LV, Info) || !Info.discardCleanups() ||
15792	Result.HasSideEffects ||
15793	!CheckLValueConstantExpression(Info, Loc: getExprLoc(),
15794	Type: Ctx.getLValueReferenceType(T: getType()), LVal: LV,
15795	Kind: ConstantExprKind::Normal, CheckedTemps))
15796	return false;
15797
15798	LV.moveInto(V&: Result.Val);
15799	return true;
15800	}
15801
15802	static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base,
15803	APValue DestroyedValue, QualType Type,
15804	SourceLocation Loc, Expr::EvalStatus &EStatus,
15805	bool IsConstantDestruction) {
15806	EvalInfo Info(Ctx, EStatus,
15807	IsConstantDestruction ? EvalInfo::EM_ConstantExpression
15808	: EvalInfo::EM_ConstantFold);
15809	Info.setEvaluatingDecl(Base, Value&: DestroyedValue,
15810	EDK: EvalInfo::EvaluatingDeclKind::Dtor);
15811	Info.InConstantContext = IsConstantDestruction;
15812
15813	LValue LVal;
15814	LVal.set(B: Base);
15815
15816	if (!HandleDestruction(Info, Loc, LVBase: Base, Value&: DestroyedValue, T: Type) ||
15817	EStatus.HasSideEffects)
15818	return false;
15819
15820	if (!Info.discardCleanups())
15821	llvm_unreachable("Unhandled cleanup; missing full expression marker?");
15822
15823	return true;
15824	}
15825
15826	bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
15827	ConstantExprKind Kind) const {
15828	assert(!isValueDependent() &&
15829	"Expression evaluator can't be called on a dependent expression.");
15830	bool IsConst;
15831	if (FastEvaluateAsRValue(Exp: this, Result, Ctx, IsConst) && Result.Val.hasValue())
15832	return true;
15833
15834	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsConstantExpr");
15835	EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
15836	EvalInfo Info(Ctx, Result, EM);
15837	Info.InConstantContext = true;
15838
15839	if (Info.EnableNewConstInterp) {
15840	if (!Info.Ctx.getInterpContext().evaluate(Parent&: Info, E: this, Result&: Result.Val))
15841	return false;
15842	return CheckConstantExpression(Info, DiagLoc: getExprLoc(),
15843	Type: getStorageType(Ctx, E: this), Value: Result.Val, Kind);
15844	}
15845
15846	// The type of the object we're initializing is 'const T' for a class NTTP.
15847	QualType T = getType();
15848	if (Kind == ConstantExprKind::ClassTemplateArgument)
15849	T.addConst();
15850
15851	// If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to
15852	// represent the result of the evaluation. CheckConstantExpression ensures
15853	// this doesn't escape.
15854	MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true);
15855	APValue::LValueBase Base(&BaseMTE);
15856	Info.setEvaluatingDecl(Base, Value&: Result.Val);
15857
15858	if (Info.EnableNewConstInterp) {
15859	if (!Info.Ctx.getInterpContext().evaluateAsRValue(Parent&: Info, E: this, Result&: Result.Val))
15860	return false;
15861	} else {
15862	LValue LVal;
15863	LVal.set(B: Base);
15864	// C++23 [intro.execution]/p5
15865	// A full-expression is [...] a constant-expression
15866	// So we need to make sure temporary objects are destroyed after having
15867	// evaluating the expression (per C++23 [class.temporary]/p4).
15868	FullExpressionRAII Scope(Info);
15869	if (!::EvaluateInPlace(Result&: Result.Val, Info, This: LVal, E: this) ||
15870	Result.HasSideEffects || !Scope.destroy())
15871	return false;
15872
15873	if (!Info.discardCleanups())
15874	llvm_unreachable("Unhandled cleanup; missing full expression marker?");
15875	}
15876
15877	if (!CheckConstantExpression(Info, DiagLoc: getExprLoc(), Type: getStorageType(Ctx, E: this),
15878	Value: Result.Val, Kind))
15879	return false;
15880	if (!CheckMemoryLeaks(Info))
15881	return false;
15882
15883	// If this is a class template argument, it's required to have constant
15884	// destruction too.
15885	if (Kind == ConstantExprKind::ClassTemplateArgument &&
15886	(!EvaluateDestruction(Ctx, Base, Result.Val, T, getBeginLoc(), Result,
15887	true) ||
15888	Result.HasSideEffects)) {
15889	// FIXME: Prefix a note to indicate that the problem is lack of constant
15890	// destruction.
15891	return false;
15892	}
15893
15894	return true;
15895	}
15896
15897	bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
15898	const VarDecl *VD,
15899	SmallVectorImpl<PartialDiagnosticAt> &Notes,
15900	bool IsConstantInitialization) const {
15901	assert(!isValueDependent() &&
15902	"Expression evaluator can't be called on a dependent expression.");
15903
15904	llvm::TimeTraceScope TimeScope("EvaluateAsInitializer", [&] {
15905	std::string Name;
15906	llvm::raw_string_ostream OS(Name);
15907	VD->printQualifiedName(OS);
15908	return Name;
15909	});
15910
15911	Expr::EvalStatus EStatus;
15912	EStatus.Diag = &Notes;
15913
15914	EvalInfo Info(Ctx, EStatus,
15915	(IsConstantInitialization &&
15916	(Ctx.getLangOpts().CPlusPlus || Ctx.getLangOpts().C23))
15917	? EvalInfo::EM_ConstantExpression
15918	: EvalInfo::EM_ConstantFold);
15919	Info.setEvaluatingDecl(VD, Value);
15920	Info.InConstantContext = IsConstantInitialization;
15921
15922	SourceLocation DeclLoc = VD->getLocation();
15923	QualType DeclTy = VD->getType();
15924
15925	if (Info.EnableNewConstInterp) {
15926	auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
15927	if (!InterpCtx.evaluateAsInitializer(Parent&: Info, VD, Result&: Value))
15928	return false;
15929
15930	return CheckConstantExpression(Info, DiagLoc: DeclLoc, Type: DeclTy, Value,
15931	Kind: ConstantExprKind::Normal);
15932	} else {
15933	LValue LVal;
15934	LVal.set(VD);
15935
15936	{
15937	// C++23 [intro.execution]/p5
15938	// A full-expression is ... an init-declarator ([dcl.decl]) or a
15939	// mem-initializer.
15940	// So we need to make sure temporary objects are destroyed after having
15941	// evaluated the expression (per C++23 [class.temporary]/p4).
15942	//
15943	// FIXME: Otherwise this may break test/Modules/pr68702.cpp because the
15944	// serialization code calls ParmVarDecl::getDefaultArg() which strips the
15945	// outermost FullExpr, such as ExprWithCleanups.
15946	FullExpressionRAII Scope(Info);
15947	if (!EvaluateInPlace(Result&: Value, Info, This: LVal, E: this,
15948	/*AllowNonLiteralTypes=*/true) ||
15949	EStatus.HasSideEffects)
15950	return false;
15951	}
15952
15953	// At this point, any lifetime-extended temporaries are completely
15954	// initialized.
15955	Info.performLifetimeExtension();
15956
15957	if (!Info.discardCleanups())
15958	llvm_unreachable("Unhandled cleanup; missing full expression marker?");
15959	}
15960
15961	return CheckConstantExpression(Info, DiagLoc: DeclLoc, Type: DeclTy, Value,
15962	Kind: ConstantExprKind::Normal) &&
15963	CheckMemoryLeaks(Info);
15964	}
15965
15966	bool VarDecl::evaluateDestruction(
15967	SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
15968	Expr::EvalStatus EStatus;
15969	EStatus.Diag = &Notes;
15970
15971	// Only treat the destruction as constant destruction if we formally have
15972	// constant initialization (or are usable in a constant expression).
15973	bool IsConstantDestruction = hasConstantInitialization();
15974
15975	// Make a copy of the value for the destructor to mutate, if we know it.
15976	// Otherwise, treat the value as default-initialized; if the destructor works
15977	// anyway, then the destruction is constant (and must be essentially empty).
15978	APValue DestroyedValue;
15979	if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
15980	DestroyedValue = *getEvaluatedValue();
15981	else if (!handleDefaultInitValue(getType(), DestroyedValue))
15982	return false;
15983
15984	if (!EvaluateDestruction(getASTContext(), this, std::move(DestroyedValue),
15985	getType(), getLocation(), EStatus,
15986	IsConstantDestruction) ||
15987	EStatus.HasSideEffects)
15988	return false;
15989
15990	ensureEvaluatedStmt()->HasConstantDestruction = true;
15991	return true;
15992	}
15993
15994	/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
15995	/// constant folded, but discard the result.
15996	bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
15997	assert(!isValueDependent() &&
15998	"Expression evaluator can't be called on a dependent expression.");
15999
16000	EvalResult Result;
16001	return EvaluateAsRValue(Result, Ctx, /* in constant context */ InConstantContext: true) &&
16002	!hasUnacceptableSideEffect(Result, SEK);
16003	}
16004
16005	APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
16006	SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
16007	assert(!isValueDependent() &&
16008	"Expression evaluator can't be called on a dependent expression.");
16009
16010	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstInt");
16011	EvalResult EVResult;
16012	EVResult.Diag = Diag;
16013	EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
16014	Info.InConstantContext = true;
16015
16016	bool Result = ::EvaluateAsRValue(E: this, Result&: EVResult, Ctx, Info);
16017	(void)Result;
16018	assert(Result && "Could not evaluate expression");
16019	assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
16020
16021	return EVResult.Val.getInt();
16022	}
16023
16024	APSInt Expr::EvaluateKnownConstIntCheckOverflow(
16025	const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
16026	assert(!isValueDependent() &&
16027	"Expression evaluator can't be called on a dependent expression.");
16028
16029	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstIntCheckOverflow");
16030	EvalResult EVResult;
16031	EVResult.Diag = Diag;
16032	EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
16033	Info.InConstantContext = true;
16034	Info.CheckingForUndefinedBehavior = true;
16035
16036	bool Result = ::EvaluateAsRValue(Info, E: this, Result&: EVResult.Val);
16037	(void)Result;
16038	assert(Result && "Could not evaluate expression");
16039	assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
16040
16041	return EVResult.Val.getInt();
16042	}
16043
16044	void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
16045	assert(!isValueDependent() &&
16046	"Expression evaluator can't be called on a dependent expression.");
16047
16048	ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateForOverflow");
16049	bool IsConst;
16050	EvalResult EVResult;
16051	if (!FastEvaluateAsRValue(Exp: this, Result&: EVResult, Ctx, IsConst)) {
16052	EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
16053	Info.CheckingForUndefinedBehavior = true;
16054	(void)::EvaluateAsRValue(Info, E: this, Result&: EVResult.Val);
16055	}
16056	}
16057
16058	bool Expr::EvalResult::isGlobalLValue() const {
16059	assert(Val.isLValue());
16060	return IsGlobalLValue(B: Val.getLValueBase());
16061	}
16062
16063	/// isIntegerConstantExpr - this recursive routine will test if an expression is
16064	/// an integer constant expression.
16065
16066	/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
16067	/// comma, etc
16068
16069	// CheckICE - This function does the fundamental ICE checking: the returned
16070	// ICEDiag contains an ICEKind indicating whether the expression is an ICE,
16071	// and a (possibly null) SourceLocation indicating the location of the problem.
16072	//
16073	// Note that to reduce code duplication, this helper does no evaluation
16074	// itself; the caller checks whether the expression is evaluatable, and
16075	// in the rare cases where CheckICE actually cares about the evaluated
16076	// value, it calls into Evaluate.
16077
16078	namespace {
16079
16080	enum ICEKind {
16081	/// This expression is an ICE.
16082	IK_ICE,
16083	/// This expression is not an ICE, but if it isn't evaluated, it's
16084	/// a legal subexpression for an ICE. This return value is used to handle
16085	/// the comma operator in C99 mode, and non-constant subexpressions.
16086	IK_ICEIfUnevaluated,
16087	/// This expression is not an ICE, and is not a legal subexpression for one.
16088	IK_NotICE
16089	};
16090
16091	struct ICEDiag {
16092	ICEKind Kind;
16093	SourceLocation Loc;
16094
16095	ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
16096	};
16097
16098	}
16099
16100	static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
16101
16102	static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
16103
16104	static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
16105	Expr::EvalResult EVResult;
16106	Expr::EvalStatus Status;
16107	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
16108
16109	Info.InConstantContext = true;
16110	if (!::EvaluateAsRValue(E, Result&: EVResult, Ctx, Info) || EVResult.HasSideEffects ||
16111	!EVResult.Val.isInt())
16112	return ICEDiag(IK_NotICE, E->getBeginLoc());
16113
16114	return NoDiag();
16115	}
16116
16117	static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
16118	assert(!E->isValueDependent() && "Should not see value dependent exprs!");
16119	if (!E->getType()->isIntegralOrEnumerationType())
16120	return ICEDiag(IK_NotICE, E->getBeginLoc());
16121
16122	switch (E->getStmtClass()) {
16123	#define ABSTRACT_STMT(Node)
16124	#define STMT(Node, Base) case Expr::Node##Class:
16125	#define EXPR(Node, Base)
16126	#include "clang/AST/StmtNodes.inc"
16127	case Expr::PredefinedExprClass:
16128	case Expr::FloatingLiteralClass:
16129	case Expr::ImaginaryLiteralClass:
16130	case Expr::StringLiteralClass:
16131	case Expr::ArraySubscriptExprClass:
16132	case Expr::MatrixSubscriptExprClass:
16133	case Expr::OMPArraySectionExprClass:
16134	case Expr::OMPArrayShapingExprClass:
16135	case Expr::OMPIteratorExprClass:
16136	case Expr::MemberExprClass:
16137	case Expr::CompoundAssignOperatorClass:
16138	case Expr::CompoundLiteralExprClass:
16139	case Expr::ExtVectorElementExprClass:
16140	case Expr::DesignatedInitExprClass:
16141	case Expr::ArrayInitLoopExprClass:
16142	case Expr::ArrayInitIndexExprClass:
16143	case Expr::NoInitExprClass:
16144	case Expr::DesignatedInitUpdateExprClass:
16145	case Expr::ImplicitValueInitExprClass:
16146	case Expr::ParenListExprClass:
16147	case Expr::VAArgExprClass:
16148	case Expr::AddrLabelExprClass:
16149	case Expr::StmtExprClass:
16150	case Expr::CXXMemberCallExprClass:
16151	case Expr::CUDAKernelCallExprClass:
16152	case Expr::CXXAddrspaceCastExprClass:
16153	case Expr::CXXDynamicCastExprClass:
16154	case Expr::CXXTypeidExprClass:
16155	case Expr::CXXUuidofExprClass:
16156	case Expr::MSPropertyRefExprClass:
16157	case Expr::MSPropertySubscriptExprClass:
16158	case Expr::CXXNullPtrLiteralExprClass:
16159	case Expr::UserDefinedLiteralClass:
16160	case Expr::CXXThisExprClass:
16161	case Expr::CXXThrowExprClass:
16162	case Expr::CXXNewExprClass:
16163	case Expr::CXXDeleteExprClass:
16164	case Expr::CXXPseudoDestructorExprClass:
16165	case Expr::UnresolvedLookupExprClass:
16166	case Expr::TypoExprClass:
16167	case Expr::RecoveryExprClass:
16168	case Expr::DependentScopeDeclRefExprClass:
16169	case Expr::CXXConstructExprClass:
16170	case Expr::CXXInheritedCtorInitExprClass:
16171	case Expr::CXXStdInitializerListExprClass:
16172	case Expr::CXXBindTemporaryExprClass:
16173	case Expr::ExprWithCleanupsClass:
16174	case Expr::CXXTemporaryObjectExprClass:
16175	case Expr::CXXUnresolvedConstructExprClass:
16176	case Expr::CXXDependentScopeMemberExprClass:
16177	case Expr::UnresolvedMemberExprClass:
16178	case Expr::ObjCStringLiteralClass:
16179	case Expr::ObjCBoxedExprClass:
16180	case Expr::ObjCArrayLiteralClass:
16181	case Expr::ObjCDictionaryLiteralClass:
16182	case Expr::ObjCEncodeExprClass:
16183	case Expr::ObjCMessageExprClass:
16184	case Expr::ObjCSelectorExprClass:
16185	case Expr::ObjCProtocolExprClass:
16186	case Expr::ObjCIvarRefExprClass:
16187	case Expr::ObjCPropertyRefExprClass:
16188	case Expr::ObjCSubscriptRefExprClass:
16189	case Expr::ObjCIsaExprClass:
16190	case Expr::ObjCAvailabilityCheckExprClass:
16191	case Expr::ShuffleVectorExprClass:
16192	case Expr::ConvertVectorExprClass:
16193	case Expr::BlockExprClass:
16194	case Expr::NoStmtClass:
16195	case Expr::OpaqueValueExprClass:
16196	case Expr::PackExpansionExprClass:
16197	case Expr::SubstNonTypeTemplateParmPackExprClass:
16198	case Expr::FunctionParmPackExprClass:
16199	case Expr::AsTypeExprClass:
16200	case Expr::ObjCIndirectCopyRestoreExprClass:
16201	case Expr::MaterializeTemporaryExprClass:
16202	case Expr::PseudoObjectExprClass:
16203	case Expr::AtomicExprClass:
16204	case Expr::LambdaExprClass:
16205	case Expr::CXXFoldExprClass:
16206	case Expr::CoawaitExprClass:
16207	case Expr::DependentCoawaitExprClass:
16208	case Expr::CoyieldExprClass:
16209	case Expr::SYCLUniqueStableNameExprClass:
16210	case Expr::CXXParenListInitExprClass:
16211	return ICEDiag(IK_NotICE, E->getBeginLoc());
16212
16213	case Expr::InitListExprClass: {
16214	// C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
16215	// form "T x = { a };" is equivalent to "T x = a;".
16216	// Unless we're initializing a reference, T is a scalar as it is known to be
16217	// of integral or enumeration type.
16218	if (E->isPRValue())
16219	if (cast<InitListExpr>(E)->getNumInits() == 1)
16220	return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
16221	return ICEDiag(IK_NotICE, E->getBeginLoc());
16222	}
16223
16224	case Expr::SizeOfPackExprClass:
16225	case Expr::GNUNullExprClass:
16226	case Expr::SourceLocExprClass:
16227	return NoDiag();
16228
16229	case Expr::PackIndexingExprClass:
16230	return CheckICE(cast<PackIndexingExpr>(E)->getSelectedExpr(), Ctx);
16231
16232	case Expr::SubstNonTypeTemplateParmExprClass:
16233	return
16234	CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
16235
16236	case Expr::ConstantExprClass:
16237	return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);
16238
16239	case Expr::ParenExprClass:
16240	return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
16241	case Expr::GenericSelectionExprClass:
16242	return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
16243	case Expr::IntegerLiteralClass:
16244	case Expr::FixedPointLiteralClass:
16245	case Expr::CharacterLiteralClass:
16246	case Expr::ObjCBoolLiteralExprClass:
16247	case Expr::CXXBoolLiteralExprClass:
16248	case Expr::CXXScalarValueInitExprClass:
16249	case Expr::TypeTraitExprClass:
16250	case Expr::ConceptSpecializationExprClass:
16251	case Expr::RequiresExprClass:
16252	case Expr::ArrayTypeTraitExprClass:
16253	case Expr::ExpressionTraitExprClass:
16254	case Expr::CXXNoexceptExprClass:
16255	return NoDiag();
16256	case Expr::CallExprClass:
16257	case Expr::CXXOperatorCallExprClass: {
16258	// C99 6.6/3 allows function calls within unevaluated subexpressions of
16259	// constant expressions, but they can never be ICEs because an ICE cannot
16260	// contain an operand of (pointer to) function type.
16261	const CallExpr *CE = cast<CallExpr>(E);
16262	if (CE->getBuiltinCallee())
16263	return CheckEvalInICE(E, Ctx);
16264	return ICEDiag(IK_NotICE, E->getBeginLoc());
16265	}
16266	case Expr::CXXRewrittenBinaryOperatorClass:
16267	return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(),
16268	Ctx);
16269	case Expr::DeclRefExprClass: {
16270	const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl();
16271	if (isa<EnumConstantDecl>(D))
16272	return NoDiag();
16273
16274	// C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified
16275	// integer variables in constant expressions:
16276	//
16277	// C++ 7.1.5.1p2
16278	// A variable of non-volatile const-qualified integral or enumeration
16279	// type initialized by an ICE can be used in ICEs.
16280	//
16281	// We sometimes use CheckICE to check the C++98 rules in C++11 mode. In
16282	// that mode, use of reference variables should not be allowed.
16283	const VarDecl *VD = dyn_cast<VarDecl>(D);
16284	if (VD && VD->isUsableInConstantExpressions(C: Ctx) &&
16285	!VD->getType()->isReferenceType())
16286	return NoDiag();
16287
16288	return ICEDiag(IK_NotICE, E->getBeginLoc());
16289	}
16290	case Expr::UnaryOperatorClass: {
16291	const UnaryOperator *Exp = cast<UnaryOperator>(E);
16292	switch (Exp->getOpcode()) {
16293	case UO_PostInc:
16294	case UO_PostDec:
16295	case UO_PreInc:
16296	case UO_PreDec:
16297	case UO_AddrOf:
16298	case UO_Deref:
16299	case UO_Coawait:
16300	// C99 6.6/3 allows increment and decrement within unevaluated
16301	// subexpressions of constant expressions, but they can never be ICEs
16302	// because an ICE cannot contain an lvalue operand.
16303	return ICEDiag(IK_NotICE, E->getBeginLoc());
16304	case UO_Extension:
16305	case UO_LNot:
16306	case UO_Plus:
16307	case UO_Minus:
16308	case UO_Not:
16309	case UO_Real:
16310	case UO_Imag:
16311	return CheckICE(E: Exp->getSubExpr(), Ctx);
16312	}
16313	llvm_unreachable("invalid unary operator class");
16314	}
16315	case Expr::OffsetOfExprClass: {
16316	// Note that per C99, offsetof must be an ICE. And AFAIK, using
16317	// EvaluateAsRValue matches the proposed gcc behavior for cases like
16318	// "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
16319	// compliance: we should warn earlier for offsetof expressions with
16320	// array subscripts that aren't ICEs, and if the array subscripts
16321	// are ICEs, the value of the offsetof must be an integer constant.
16322	return CheckEvalInICE(E, Ctx);
16323	}
16324	case Expr::UnaryExprOrTypeTraitExprClass: {
16325	const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
16326	if ((Exp->getKind() == UETT_SizeOf) &&
16327	Exp->getTypeOfArgument()->isVariableArrayType())
16328	return ICEDiag(IK_NotICE, E->getBeginLoc());
16329	return NoDiag();
16330	}
16331	case Expr::BinaryOperatorClass: {
16332	const BinaryOperator *Exp = cast<BinaryOperator>(E);
16333	switch (Exp->getOpcode()) {
16334	case BO_PtrMemD:
16335	case BO_PtrMemI:
16336	case BO_Assign:
16337	case BO_MulAssign:
16338	case BO_DivAssign:
16339	case BO_RemAssign:
16340	case BO_AddAssign:
16341	case BO_SubAssign:
16342	case BO_ShlAssign:
16343	case BO_ShrAssign:
16344	case BO_AndAssign:
16345	case BO_XorAssign:
16346	case BO_OrAssign:
16347	// C99 6.6/3 allows assignments within unevaluated subexpressions of
16348	// constant expressions, but they can never be ICEs because an ICE cannot
16349	// contain an lvalue operand.
16350	return ICEDiag(IK_NotICE, E->getBeginLoc());
16351
16352	case BO_Mul:
16353	case BO_Div:
16354	case BO_Rem:
16355	case BO_Add:
16356	case BO_Sub:
16357	case BO_Shl:
16358	case BO_Shr:
16359	case BO_LT:
16360	case BO_GT:
16361	case BO_LE:
16362	case BO_GE:
16363	case BO_EQ:
16364	case BO_NE:
16365	case BO_And:
16366	case BO_Xor:
16367	case BO_Or:
16368	case BO_Comma:
16369	case BO_Cmp: {
16370	ICEDiag LHSResult = CheckICE(E: Exp->getLHS(), Ctx);
16371	ICEDiag RHSResult = CheckICE(E: Exp->getRHS(), Ctx);
16372	if (Exp->getOpcode() == BO_Div ||
16373	Exp->getOpcode() == BO_Rem) {
16374	// EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
16375	// we don't evaluate one.
16376	if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
16377	llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
16378	if (REval == 0)
16379	return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
16380	if (REval.isSigned() && REval.isAllOnes()) {
16381	llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
16382	if (LEval.isMinSignedValue())
16383	return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
16384	}
16385	}
16386	}
16387	if (Exp->getOpcode() == BO_Comma) {
16388	if (Ctx.getLangOpts().C99) {
16389	// C99 6.6p3 introduces a strange edge case: comma can be in an ICE
16390	// if it isn't evaluated.
16391	if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
16392	return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
16393	} else {
16394	// In both C89 and C++, commas in ICEs are illegal.
16395	return ICEDiag(IK_NotICE, E->getBeginLoc());
16396	}
16397	}
16398	return Worst(A: LHSResult, B: RHSResult);
16399	}
16400	case BO_LAnd:
16401	case BO_LOr: {
16402	ICEDiag LHSResult = CheckICE(E: Exp->getLHS(), Ctx);
16403	ICEDiag RHSResult = CheckICE(E: Exp->getRHS(), Ctx);
16404	if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
16405	// Rare case where the RHS has a comma "side-effect"; we need
16406	// to actually check the condition to see whether the side
16407	// with the comma is evaluated.
16408	if ((Exp->getOpcode() == BO_LAnd) !=
16409	(Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
16410	return RHSResult;
16411	return NoDiag();
16412	}
16413
16414	return Worst(A: LHSResult, B: RHSResult);
16415	}
16416	}
16417	llvm_unreachable("invalid binary operator kind");
16418	}
16419	case Expr::ImplicitCastExprClass:
16420	case Expr::CStyleCastExprClass:
16421	case Expr::CXXFunctionalCastExprClass:
16422	case Expr::CXXStaticCastExprClass:
16423	case Expr::CXXReinterpretCastExprClass:
16424	case Expr::CXXConstCastExprClass:
16425	case Expr::ObjCBridgedCastExprClass: {
16426	const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
16427	if (isa<ExplicitCastExpr>(E)) {
16428	if (const FloatingLiteral *FL
16429	= dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
16430	unsigned DestWidth = Ctx.getIntWidth(T: E->getType());
16431	bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
16432	APSInt IgnoredVal(DestWidth, !DestSigned);
16433	bool Ignored;
16434	// If the value does not fit in the destination type, the behavior is
16435	// undefined, so we are not required to treat it as a constant
16436	// expression.
16437	if (FL->getValue().convertToInteger(Result&: IgnoredVal,
16438	RM: llvm::APFloat::rmTowardZero,
16439	IsExact: &Ignored) & APFloat::opInvalidOp)
16440	return ICEDiag(IK_NotICE, E->getBeginLoc());
16441	return NoDiag();
16442	}
16443	}
16444	switch (cast<CastExpr>(E)->getCastKind()) {
16445	case CK_LValueToRValue:
16446	case CK_AtomicToNonAtomic:
16447	case CK_NonAtomicToAtomic:
16448	case CK_NoOp:
16449	case CK_IntegralToBoolean:
16450	case CK_IntegralCast:
16451	return CheckICE(E: SubExpr, Ctx);
16452	default:
16453	return ICEDiag(IK_NotICE, E->getBeginLoc());
16454	}
16455	}
16456	case Expr::BinaryConditionalOperatorClass: {
16457	const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
16458	ICEDiag CommonResult = CheckICE(E: Exp->getCommon(), Ctx);
16459	if (CommonResult.Kind == IK_NotICE) return CommonResult;
16460	ICEDiag FalseResult = CheckICE(E: Exp->getFalseExpr(), Ctx);
16461	if (FalseResult.Kind == IK_NotICE) return FalseResult;
16462	if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
16463	if (FalseResult.Kind == IK_ICEIfUnevaluated &&
16464	Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
16465	return FalseResult;
16466	}
16467	case Expr::ConditionalOperatorClass: {
16468	const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
16469	// If the condition (ignoring parens) is a __builtin_constant_p call,
16470	// then only the true side is actually considered in an integer constant
16471	// expression, and it is fully evaluated. This is an important GNU
16472	// extension. See GCC PR38377 for discussion.
16473	if (const CallExpr *CallCE
16474	= dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
16475	if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
16476	return CheckEvalInICE(E, Ctx);
16477	ICEDiag CondResult = CheckICE(E: Exp->getCond(), Ctx);
16478	if (CondResult.Kind == IK_NotICE)
16479	return CondResult;
16480
16481	ICEDiag TrueResult = CheckICE(E: Exp->getTrueExpr(), Ctx);
16482	ICEDiag FalseResult = CheckICE(E: Exp->getFalseExpr(), Ctx);
16483
16484	if (TrueResult.Kind == IK_NotICE)
16485	return TrueResult;
16486	if (FalseResult.Kind == IK_NotICE)
16487	return FalseResult;
16488	if (CondResult.Kind == IK_ICEIfUnevaluated)
16489	return CondResult;
16490	if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
16491	return NoDiag();
16492	// Rare case where the diagnostics depend on which side is evaluated
16493	// Note that if we get here, CondResult is 0, and at least one of
16494	// TrueResult and FalseResult is non-zero.
16495	if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
16496	return FalseResult;
16497	return TrueResult;
16498	}
16499	case Expr::CXXDefaultArgExprClass:
16500	return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
16501	case Expr::CXXDefaultInitExprClass:
16502	return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
16503	case Expr::ChooseExprClass: {
16504	return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
16505	}
16506	case Expr::BuiltinBitCastExprClass: {
16507	if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
16508	return ICEDiag(IK_NotICE, E->getBeginLoc());
16509	return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
16510	}
16511	}
16512
16513	llvm_unreachable("Invalid StmtClass!");
16514	}
16515
16516	/// Evaluate an expression as a C++11 integral constant expression.
16517	static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
16518	const Expr *E,
16519	llvm::APSInt *Value,
16520	SourceLocation *Loc) {
16521	if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
16522	if (Loc) *Loc = E->getExprLoc();
16523	return false;
16524	}
16525
16526	APValue Result;
16527	if (!E->isCXX11ConstantExpr(Ctx, Result: &Result, Loc))
16528	return false;
16529
16530	if (!Result.isInt()) {
16531	if (Loc) *Loc = E->getExprLoc();
16532	return false;
16533	}
16534
16535	if (Value) *Value = Result.getInt();
16536	return true;
16537	}
16538
16539	bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
16540	SourceLocation *Loc) const {
16541	assert(!isValueDependent() &&
16542	"Expression evaluator can't be called on a dependent expression.");
16543
16544	ExprTimeTraceScope TimeScope(this, Ctx, "isIntegerConstantExpr");
16545
16546	if (Ctx.getLangOpts().CPlusPlus11)
16547	return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, E: this, Value: nullptr, Loc);
16548
16549	ICEDiag D = CheckICE(E: this, Ctx);
16550	if (D.Kind != IK_ICE) {
16551	if (Loc) *Loc = D.Loc;
16552	return false;
16553	}
16554	return true;
16555	}
16556
16557	std::optional<llvm::APSInt>
16558	Expr::getIntegerConstantExpr(const ASTContext &Ctx, SourceLocation *Loc) const {
16559	if (isValueDependent()) {
16560	// Expression evaluator can't succeed on a dependent expression.
16561	return std::nullopt;
16562	}
16563
16564	APSInt Value;
16565
16566	if (Ctx.getLangOpts().CPlusPlus11) {
16567	if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, E: this, Value: &Value, Loc))
16568	return Value;
16569	return std::nullopt;
16570	}
16571
16572	if (!isIntegerConstantExpr(Ctx, Loc))
16573	return std::nullopt;
16574
16575	// The only possible side-effects here are due to UB discovered in the
16576	// evaluation (for instance, INT_MAX + 1). In such a case, we are still
16577	// required to treat the expression as an ICE, so we produce the folded
16578	// value.
16579	EvalResult ExprResult;
16580	Expr::EvalStatus Status;
16581	EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
16582	Info.InConstantContext = true;
16583
16584	if (!::EvaluateAsInt(E: this, ExprResult, Ctx, AllowSideEffects: SE_AllowSideEffects, Info))
16585	llvm_unreachable("ICE cannot be evaluated!");
16586
16587	return ExprResult.Val.getInt();
16588	}
16589
16590	bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
16591	assert(!isValueDependent() &&
16592	"Expression evaluator can't be called on a dependent expression.");
16593
16594	return CheckICE(E: this, Ctx).Kind == IK_ICE;
16595	}
16596
16597	bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
16598	SourceLocation *Loc) const {
16599	assert(!isValueDependent() &&
16600	"Expression evaluator can't be called on a dependent expression.");
16601
16602	// We support this checking in C++98 mode in order to diagnose compatibility
16603	// issues.
16604	assert(Ctx.getLangOpts().CPlusPlus);
16605
16606	// Build evaluation settings.
16607	Expr::EvalStatus Status;
16608	SmallVector<PartialDiagnosticAt, 8> Diags;
16609	Status.Diag = &Diags;
16610	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
16611
16612	APValue Scratch;
16613	bool IsConstExpr =
16614	::EvaluateAsRValue(Info, E: this, Result&: Result ? *Result : Scratch) &&
16615	// FIXME: We don't produce a diagnostic for this, but the callers that
16616	// call us on arbitrary full-expressions should generally not care.
16617	Info.discardCleanups() && !Status.HasSideEffects;
16618
16619	if (!Diags.empty()) {
16620	IsConstExpr = false;
16621	if (Loc) *Loc = Diags[0].first;
16622	} else if (!IsConstExpr) {
16623	// FIXME: This shouldn't happen.
16624	if (Loc) *Loc = getExprLoc();
16625	}
16626
16627	return IsConstExpr;
16628	}
16629
16630	bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
16631	const FunctionDecl *Callee,
16632	ArrayRef<const Expr*> Args,
16633	const Expr *This) const {
16634	assert(!isValueDependent() &&
16635	"Expression evaluator can't be called on a dependent expression.");
16636
16637	llvm::TimeTraceScope TimeScope("EvaluateWithSubstitution", [&] {
16638	std::string Name;
16639	llvm::raw_string_ostream OS(Name);
16640	Callee->getNameForDiagnostic(OS, Policy: Ctx.getPrintingPolicy(),
16641	/*Qualified=*/true);
16642	return Name;
16643	});
16644
16645	Expr::EvalStatus Status;
16646	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
16647	Info.InConstantContext = true;
16648
16649	LValue ThisVal;
16650	const LValue *ThisPtr = nullptr;
16651	if (This) {
16652	#ifndef NDEBUG
16653	auto *MD = dyn_cast<CXXMethodDecl>(Val: Callee);
16654	assert(MD && "Don't provide `this` for non-methods.");
16655	assert(MD->isImplicitObjectMemberFunction() &&
16656	"Don't provide `this` for methods without an implicit object.");
16657	#endif
16658	if (!This->isValueDependent() &&
16659	EvaluateObjectArgument(Info, Object: This, This&: ThisVal) &&
16660	!Info.EvalStatus.HasSideEffects)
16661	ThisPtr = &ThisVal;
16662
16663	// Ignore any side-effects from a failed evaluation. This is safe because
16664	// they can't interfere with any other argument evaluation.
16665	Info.EvalStatus.HasSideEffects = false;
16666	}
16667
16668	CallRef Call = Info.CurrentCall->createCall(Callee);
16669	for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
16670	I != E; ++I) {
16671	unsigned Idx = I - Args.begin();
16672	if (Idx >= Callee->getNumParams())
16673	break;
16674	const ParmVarDecl *PVD = Callee->getParamDecl(i: Idx);
16675	if ((*I)->isValueDependent() ||
16676	!EvaluateCallArg(PVD, Arg: *I, Call, Info) ||
16677	Info.EvalStatus.HasSideEffects) {
16678	// If evaluation fails, throw away the argument entirely.
16679	if (APValue *Slot = Info.getParamSlot(Call, PVD))
16680	*Slot = APValue();
16681	}
16682
16683	// Ignore any side-effects from a failed evaluation. This is safe because
16684	// they can't interfere with any other argument evaluation.
16685	Info.EvalStatus.HasSideEffects = false;
16686	}
16687
16688	// Parameter cleanups happen in the caller and are not part of this
16689	// evaluation.
16690	Info.discardCleanups();
16691	Info.EvalStatus.HasSideEffects = false;
16692
16693	// Build fake call to Callee.
16694	CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, This,
16695	Call);
16696	// FIXME: Missing ExprWithCleanups in enable_if conditions?
16697	FullExpressionRAII Scope(Info);
16698	return Evaluate(Result&: Value, Info, E: this) && Scope.destroy() &&
16699	!Info.EvalStatus.HasSideEffects;
16700	}
16701
16702	bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
16703	SmallVectorImpl<
16704	PartialDiagnosticAt> &Diags) {
16705	// FIXME: It would be useful to check constexpr function templates, but at the
16706	// moment the constant expression evaluator cannot cope with the non-rigorous
16707	// ASTs which we build for dependent expressions.
16708	if (FD->isDependentContext())
16709	return true;
16710
16711	llvm::TimeTraceScope TimeScope("isPotentialConstantExpr", [&] {
16712	std::string Name;
16713	llvm::raw_string_ostream OS(Name);
16714	FD->getNameForDiagnostic(OS, Policy: FD->getASTContext().getPrintingPolicy(),
16715	/*Qualified=*/true);
16716	return Name;
16717	});
16718
16719	Expr::EvalStatus Status;
16720	Status.Diag = &Diags;
16721
16722	EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
16723	Info.InConstantContext = true;
16724	Info.CheckingPotentialConstantExpression = true;
16725
16726	// The constexpr VM attempts to compile all methods to bytecode here.
16727	if (Info.EnableNewConstInterp) {
16728	Info.Ctx.getInterpContext().isPotentialConstantExpr(Parent&: Info, FnDecl: FD);
16729	return Diags.empty();
16730	}
16731
16732	const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Val: FD);
16733	const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
16734
16735	// Fabricate an arbitrary expression on the stack and pretend that it
16736	// is a temporary being used as the 'this' pointer.
16737	LValue This;
16738	ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
16739	This.set({&VIE, Info.CurrentCall->Index});
16740
16741	ArrayRef<const Expr*> Args;
16742
16743	APValue Scratch;
16744	if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Val: FD)) {
16745	// Evaluate the call as a constant initializer, to allow the construction
16746	// of objects of non-literal types.
16747	Info.setEvaluatingDecl(Base: This.getLValueBase(), Value&: Scratch);
16748	HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
16749	} else {
16750	SourceLocation Loc = FD->getLocation();
16751	HandleFunctionCall(
16752	Loc, FD, (MD && MD->isImplicitObjectMemberFunction()) ? &This : nullptr,
16753	&VIE, Args, CallRef(), FD->getBody(), Info, Scratch,
16754	/*ResultSlot=*/nullptr);
16755	}
16756
16757	return Diags.empty();
16758	}
16759
16760	bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
16761	const FunctionDecl *FD,
16762	SmallVectorImpl<
16763	PartialDiagnosticAt> &Diags) {
16764	assert(!E->isValueDependent() &&
16765	"Expression evaluator can't be called on a dependent expression.");
16766
16767	Expr::EvalStatus Status;
16768	Status.Diag = &Diags;
16769
16770	EvalInfo Info(FD->getASTContext(), Status,
16771	EvalInfo::EM_ConstantExpressionUnevaluated);
16772	Info.InConstantContext = true;
16773	Info.CheckingPotentialConstantExpression = true;
16774
16775	// Fabricate a call stack frame to give the arguments a plausible cover story.
16776	CallStackFrame Frame(Info, SourceLocation(), FD, /*This=*/nullptr,
16777	/*CallExpr=*/nullptr, CallRef());
16778
16779	APValue ResultScratch;
16780	Evaluate(Result&: ResultScratch, Info, E);
16781	return Diags.empty();
16782	}
16783
16784	bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
16785	unsigned Type) const {
16786	if (!getType()->isPointerType())
16787	return false;
16788
16789	Expr::EvalStatus Status;
16790	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
16791	return tryEvaluateBuiltinObjectSize(E: this, Type, Info, Size&: Result);
16792	}
16793
16794	static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result,
16795	EvalInfo &Info) {
16796	if (!E->getType()->hasPointerRepresentation() || !E->isPRValue())
16797	return false;
16798
16799	LValue String;
16800
16801	if (!EvaluatePointer(E, Result&: String, Info))
16802	return false;
16803
16804	QualType CharTy = E->getType()->getPointeeType();
16805
16806	// Fast path: if it's a string literal, search the string value.
16807	if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
16808	Val: String.getLValueBase().dyn_cast<const Expr *>())) {
16809	StringRef Str = S->getBytes();
16810	int64_t Off = String.Offset.getQuantity();
16811	if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
16812	S->getCharByteWidth() == 1 &&
16813	// FIXME: Add fast-path for wchar_t too.
16814	Info.Ctx.hasSameUnqualifiedType(T1: CharTy, T2: Info.Ctx.CharTy)) {
16815	Str = Str.substr(Start: Off);
16816
16817	StringRef::size_type Pos = Str.find(C: 0);
16818	if (Pos != StringRef::npos)
16819	Str = Str.substr(Start: 0, N: Pos);
16820
16821	Result = Str.size();
16822	return true;
16823	}
16824
16825	// Fall through to slow path.
16826	}
16827
16828	// Slow path: scan the bytes of the string looking for the terminating 0.
16829	for (uint64_t Strlen = 0; /**/; ++Strlen) {
16830	APValue Char;
16831	if (!handleLValueToRValueConversion(Info, Conv: E, Type: CharTy, LVal: String, RVal&: Char) ||
16832	!Char.isInt())
16833	return false;
16834	if (!Char.getInt()) {
16835	Result = Strlen;
16836	return true;
16837	}
16838	if (!HandleLValueArrayAdjustment(Info, E, LVal&: String, EltTy: CharTy, Adjustment: 1))
16839	return false;
16840	}
16841	}
16842
16843	bool Expr::EvaluateCharRangeAsString(std::string &Result,
16844	const Expr *SizeExpression,
16845	const Expr *PtrExpression, ASTContext &Ctx,
16846	EvalResult &Status) const {
16847	LValue String;
16848	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
16849	Info.InConstantContext = true;
16850
16851	FullExpressionRAII Scope(Info);
16852	APSInt SizeValue;
16853	if (!::EvaluateInteger(E: SizeExpression, Result&: SizeValue, Info))
16854	return false;
16855
16856	uint64_t Size = SizeValue.getZExtValue();
16857
16858	if (!::EvaluatePointer(E: PtrExpression, Result&: String, Info))
16859	return false;
16860
16861	QualType CharTy = PtrExpression->getType()->getPointeeType();
16862	for (uint64_t I = 0; I < Size; ++I) {
16863	APValue Char;
16864	if (!handleLValueToRValueConversion(Info, Conv: PtrExpression, Type: CharTy, LVal: String,
16865	RVal&: Char))
16866	return false;
16867
16868	APSInt C = Char.getInt();
16869	Result.push_back(c: static_cast<char>(C.getExtValue()));
16870	if (!HandleLValueArrayAdjustment(Info, E: PtrExpression, LVal&: String, EltTy: CharTy, Adjustment: 1))
16871	return false;
16872	}
16873	if (!Scope.destroy())
16874	return false;
16875
16876	if (!CheckMemoryLeaks(Info))
16877	return false;
16878
16879	return true;
16880	}
16881
16882	bool Expr::tryEvaluateStrLen(uint64_t &Result, ASTContext &Ctx) const {
16883	Expr::EvalStatus Status;
16884	EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
16885	return EvaluateBuiltinStrLen(E: this, Result, Info);
16886	}
16887