1	//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===//
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 semantic analysis for statements.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "CheckExprLifetime.h"
14	#include "clang/AST/ASTContext.h"
15	#include "clang/AST/ASTLambda.h"
16	#include "clang/AST/CXXInheritance.h"
17	#include "clang/AST/CharUnits.h"
18	#include "clang/AST/DeclObjC.h"
19	#include "clang/AST/DynamicRecursiveASTVisitor.h"
20	#include "clang/AST/EvaluatedExprVisitor.h"
21	#include "clang/AST/ExprCXX.h"
22	#include "clang/AST/ExprObjC.h"
23	#include "clang/AST/IgnoreExpr.h"
24	#include "clang/AST/StmtCXX.h"
25	#include "clang/AST/StmtObjC.h"
26	#include "clang/AST/TypeLoc.h"
27	#include "clang/AST/TypeOrdering.h"
28	#include "clang/Basic/TargetInfo.h"
29	#include "clang/Lex/Preprocessor.h"
30	#include "clang/Sema/EnterExpressionEvaluationContext.h"
31	#include "clang/Sema/Initialization.h"
32	#include "clang/Sema/Lookup.h"
33	#include "clang/Sema/Ownership.h"
34	#include "clang/Sema/Scope.h"
35	#include "clang/Sema/ScopeInfo.h"
36	#include "clang/Sema/SemaCUDA.h"
37	#include "clang/Sema/SemaObjC.h"
38	#include "clang/Sema/SemaOpenMP.h"
39	#include "llvm/ADT/ArrayRef.h"
40	#include "llvm/ADT/DenseMap.h"
41	#include "llvm/ADT/STLExtras.h"
42	#include "llvm/ADT/SmallVector.h"
43	#include "llvm/ADT/StringExtras.h"
44
45	using namespace clang;
46	using namespace sema;
47
48	StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
49	if (FE.isInvalid())
50	return StmtError();
51
52	FE = ActOnFinishFullExpr(Expr: FE.get(), CC: FE.get()->getExprLoc(), DiscardedValue);
53	if (FE.isInvalid())
54	return StmtError();
55
56	// C99 6.8.3p2: The expression in an expression statement is evaluated as a
57	// void expression for its side effects. Conversion to void allows any
58	// operand, even incomplete types.
59
60	// Same thing in for stmt first clause (when expr) and third clause.
61	return StmtResult(FE.getAs<Stmt>());
62	}
63
64
65	StmtResult Sema::ActOnExprStmtError() {
66	DiscardCleanupsInEvaluationContext();
67	return StmtError();
68	}
69
70	StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
71	bool HasLeadingEmptyMacro) {
72	return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
73	}
74
75	StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
76	SourceLocation EndLoc) {
77	DeclGroupRef DG = dg.get();
78
79	// If we have an invalid decl, just return an error.
80	if (DG.isNull()) return StmtError();
81
82	return new (Context) DeclStmt(DG, StartLoc, EndLoc);
83	}
84
85	void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
86	DeclGroupRef DG = dg.get();
87
88	// If we don't have a declaration, or we have an invalid declaration,
89	// just return.
90	if (DG.isNull() || !DG.isSingleDecl())
91	return;
92
93	Decl *decl = DG.getSingleDecl();
94	if (!decl || decl->isInvalidDecl())
95	return;
96
97	// Only variable declarations are permitted.
98	VarDecl *var = dyn_cast<VarDecl>(Val: decl);
99	if (!var) {
100	Diag(Loc: decl->getLocation(), DiagID: diag::err_non_variable_decl_in_for);
101	decl->setInvalidDecl();
102	return;
103	}
104
105	// foreach variables are never actually initialized in the way that
106	// the parser came up with.
107	var->setInit(nullptr);
108
109	// In ARC, we don't need to retain the iteration variable of a fast
110	// enumeration loop. Rather than actually trying to catch that
111	// during declaration processing, we remove the consequences here.
112	if (getLangOpts().ObjCAutoRefCount) {
113	QualType type = var->getType();
114
115	// Only do this if we inferred the lifetime. Inferred lifetime
116	// will show up as a local qualifier because explicit lifetime
117	// should have shown up as an AttributedType instead.
118	if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
119	// Add 'const' and mark the variable as pseudo-strong.
120	var->setType(type.withConst());
121	var->setARCPseudoStrong(true);
122	}
123	}
124	}
125
126	/// Diagnose unused comparisons, both builtin and overloaded operators.
127	/// For '==' and '!=', suggest fixits for '=' or '|='.
128	///
129	/// Adding a cast to void (or other expression wrappers) will prevent the
130	/// warning from firing.
131	static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
132	SourceLocation Loc;
133	bool CanAssign;
134	enum { Equality, Inequality, Relational, ThreeWay } Kind;
135
136	if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(Val: E)) {
137	if (!Op->isComparisonOp())
138	return false;
139
140	if (Op->getOpcode() == BO_EQ)
141	Kind = Equality;
142	else if (Op->getOpcode() == BO_NE)
143	Kind = Inequality;
144	else if (Op->getOpcode() == BO_Cmp)
145	Kind = ThreeWay;
146	else {
147	assert(Op->isRelationalOp());
148	Kind = Relational;
149	}
150	Loc = Op->getOperatorLoc();
151	CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
152	} else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(Val: E)) {
153	switch (Op->getOperator()) {
154	case OO_EqualEqual:
155	Kind = Equality;
156	break;
157	case OO_ExclaimEqual:
158	Kind = Inequality;
159	break;
160	case OO_Less:
161	case OO_Greater:
162	case OO_GreaterEqual:
163	case OO_LessEqual:
164	Kind = Relational;
165	break;
166	case OO_Spaceship:
167	Kind = ThreeWay;
168	break;
169	default:
170	return false;
171	}
172
173	Loc = Op->getOperatorLoc();
174	CanAssign = Op->getArg(Arg: 0)->IgnoreParenImpCasts()->isLValue();
175	} else {
176	// Not a typo-prone comparison.
177	return false;
178	}
179
180	// Suppress warnings when the operator, suspicious as it may be, comes from
181	// a macro expansion.
182	if (S.SourceMgr.isMacroBodyExpansion(Loc))
183	return false;
184
185	S.Diag(Loc, DiagID: diag::warn_unused_comparison)
186	<< (unsigned)Kind << E->getSourceRange();
187
188	// If the LHS is a plausible entity to assign to, provide a fixit hint to
189	// correct common typos.
190	if (CanAssign) {
191	if (Kind == Inequality)
192	S.Diag(Loc, DiagID: diag::note_inequality_comparison_to_or_assign)
193	<< FixItHint::CreateReplacement(RemoveRange: Loc, Code: "|=");
194	else if (Kind == Equality)
195	S.Diag(Loc, DiagID: diag::note_equality_comparison_to_assign)
196	<< FixItHint::CreateReplacement(RemoveRange: Loc, Code: "=");
197	}
198
199	return true;
200	}
201
202	static bool DiagnoseNoDiscard(Sema &S, const NamedDecl *OffendingDecl,
203	const WarnUnusedResultAttr *A, SourceLocation Loc,
204	SourceRange R1, SourceRange R2, bool IsCtor) {
205	if (!A)
206	return false;
207	StringRef Msg = A->getMessage();
208
209	if (Msg.empty()) {
210	if (OffendingDecl)
211	return S.Diag(Loc, DiagID: diag::warn_unused_return_type)
212	<< IsCtor << A << OffendingDecl << false << R1 << R2;
213	if (IsCtor)
214	return S.Diag(Loc, DiagID: diag::warn_unused_constructor)
215	<< A << false << R1 << R2;
216	return S.Diag(Loc, DiagID: diag::warn_unused_result) << A << false << R1 << R2;
217	}
218
219	if (OffendingDecl)
220	return S.Diag(Loc, DiagID: diag::warn_unused_return_type)
221	<< IsCtor << A << OffendingDecl << true << Msg << R1 << R2;
222	if (IsCtor)
223	return S.Diag(Loc, DiagID: diag::warn_unused_constructor)
224	<< A << true << Msg << R1 << R2;
225	return S.Diag(Loc, DiagID: diag::warn_unused_result) << A << true << Msg << R1 << R2;
226	}
227
228	namespace {
229
230	// Diagnoses unused expressions that call functions marked [[nodiscard]],
231	// [[gnu::warn_unused_result]] and similar.
232	// Additionally, a DiagID can be provided to emit a warning in additional
233	// contexts (such as for an unused LHS of a comma expression)
234	void DiagnoseUnused(Sema &S, const Expr *E, std::optional<unsigned> DiagID) {
235	bool NoDiscardOnly = !DiagID.has_value();
236
237	// If we are in an unevaluated expression context, then there can be no unused
238	// results because the results aren't expected to be used in the first place.
239	if (S.isUnevaluatedContext())
240	return;
241
242	SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
243	// In most cases, we don't want to warn if the expression is written in a
244	// macro body, or if the macro comes from a system header. If the offending
245	// expression is a call to a function with the warn_unused_result attribute,
246	// we warn no matter the location. Because of the order in which the various
247	// checks need to happen, we factor out the macro-related test here.
248	bool ShouldSuppress = S.SourceMgr.isMacroBodyExpansion(Loc: ExprLoc) ||
249	S.SourceMgr.isInSystemMacro(loc: ExprLoc);
250
251	const Expr *WarnExpr;
252	SourceLocation Loc;
253	SourceRange R1, R2;
254	if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Ctx&: S.Context))
255	return;
256
257	if (!NoDiscardOnly) {
258	// If this is a GNU statement expression expanded from a macro, it is
259	// probably unused because it is a function-like macro that can be used as
260	// either an expression or statement. Don't warn, because it is almost
261	// certainly a false positive.
262	if (isa<StmtExpr>(Val: E) && Loc.isMacroID())
263	return;
264
265	// Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
266	// That macro is frequently used to suppress "unused parameter" warnings,
267	// but its implementation makes clang's -Wunused-value fire. Prevent this.
268	if (isa<ParenExpr>(Val: E->IgnoreImpCasts()) && Loc.isMacroID()) {
269	SourceLocation SpellLoc = Loc;
270	if (S.findMacroSpelling(loc&: SpellLoc, name: "UNREFERENCED_PARAMETER"))
271	return;
272	}
273	}
274
275	// Okay, we have an unused result. Depending on what the base expression is,
276	// we might want to make a more specific diagnostic. Check for one of these
277	// cases now.
278	if (const FullExpr *Temps = dyn_cast<FullExpr>(Val: E))
279	E = Temps->getSubExpr();
280	if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(Val: E))
281	E = TempExpr->getSubExpr();
282
283	if (DiagnoseUnusedComparison(S, E))
284	return;
285
286	E = WarnExpr;
287	if (const auto *Cast = dyn_cast<CastExpr>(Val: E))
288	if (Cast->getCastKind() == CK_NoOp ||
289	Cast->getCastKind() == CK_ConstructorConversion ||
290	Cast->getCastKind() == CK_IntegralCast)
291	E = Cast->getSubExpr()->IgnoreImpCasts();
292
293	if (const CallExpr *CE = dyn_cast<CallExpr>(Val: E)) {
294	if (E->getType()->isVoidType())
295	return;
296
297	auto [OffendingDecl, A] = CE->getUnusedResultAttr(Ctx: S.Context);
298	if (DiagnoseNoDiscard(S, OffendingDecl,
299	A: cast_or_null<WarnUnusedResultAttr>(Val: A), Loc, R1, R2,
300	/*isCtor=*/IsCtor: false))
301	return;
302
303	// If the callee has attribute pure, const, or warn_unused_result, warn with
304	// a more specific message to make it clear what is happening. If the call
305	// is written in a macro body, only warn if it has the warn_unused_result
306	// attribute.
307	if (const Decl *FD = CE->getCalleeDecl()) {
308	if (ShouldSuppress)
309	return;
310	if (FD->hasAttr<PureAttr>()) {
311	S.Diag(Loc, DiagID: diag::warn_unused_call) << R1 << R2 << "pure";
312	return;
313	}
314	if (FD->hasAttr<ConstAttr>()) {
315	S.Diag(Loc, DiagID: diag::warn_unused_call) << R1 << R2 << "const";
316	return;
317	}
318	}
319	} else if (const auto *CE = dyn_cast<CXXConstructExpr>(Val: E)) {
320	if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
321	const NamedDecl *OffendingDecl = nullptr;
322	const auto *A = Ctor->getAttr<WarnUnusedResultAttr>();
323	if (!A) {
324	OffendingDecl = Ctor->getParent();
325	A = OffendingDecl->getAttr<WarnUnusedResultAttr>();
326	}
327	if (DiagnoseNoDiscard(S, OffendingDecl, A, Loc, R1, R2,
328	/*isCtor=*/IsCtor: true))
329	return;
330	}
331	} else if (const auto *ILE = dyn_cast<InitListExpr>(Val: E)) {
332	if (const TagDecl *TD = ILE->getType()->getAsTagDecl()) {
333
334	if (DiagnoseNoDiscard(S, OffendingDecl: TD, A: TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
335	R2, /*isCtor=*/IsCtor: false))
336	return;
337	}
338	} else if (ShouldSuppress)
339	return;
340
341	E = WarnExpr;
342	if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(Val: E)) {
343	if (S.getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
344	S.Diag(Loc, DiagID: diag::err_arc_unused_init_message) << R1;
345	return;
346	}
347	const ObjCMethodDecl *MD = ME->getMethodDecl();
348	if (MD) {
349	if (DiagnoseNoDiscard(S, OffendingDecl: nullptr, A: MD->getAttr<WarnUnusedResultAttr>(),
350	Loc, R1, R2,
351	/*isCtor=*/IsCtor: false))
352	return;
353	}
354	} else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Val: E)) {
355	const Expr *Source = POE->getSyntacticForm();
356	// Handle the actually selected call of an OpenMP specialized call.
357	if (S.LangOpts.OpenMP && isa<CallExpr>(Val: Source) &&
358	POE->getNumSemanticExprs() == 1 &&
359	isa<CallExpr>(Val: POE->getSemanticExpr(index: 0)))
360	return DiagnoseUnused(S, E: POE->getSemanticExpr(index: 0), DiagID);
361	if (isa<ObjCSubscriptRefExpr>(Val: Source))
362	DiagID = diag::warn_unused_container_subscript_expr;
363	else if (isa<ObjCPropertyRefExpr>(Val: Source))
364	DiagID = diag::warn_unused_property_expr;
365	} else if (const CXXFunctionalCastExpr *FC
366	= dyn_cast<CXXFunctionalCastExpr>(Val: E)) {
367	const Expr *E = FC->getSubExpr();
368	if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(Val: E))
369	E = TE->getSubExpr();
370	if (isa<CXXTemporaryObjectExpr>(Val: E))
371	return;
372	if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: E))
373	if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
374	if (!RD->getAttr<WarnUnusedAttr>())
375	return;
376	}
377
378	if (NoDiscardOnly)
379	return;
380
381	// Diagnose "(void*) blah" as a typo for "(void) blah".
382	if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(Val: E)) {
383	TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
384	QualType T = TI->getType();
385
386	// We really do want to use the non-canonical type here.
387	if (T == S.Context.VoidPtrTy) {
388	PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
389
390	S.Diag(Loc, DiagID: diag::warn_unused_voidptr)
391	<< FixItHint::CreateRemoval(RemoveRange: TL.getStarLoc());
392	return;
393	}
394	}
395
396	// Tell the user to assign it into a variable to force a volatile load if this
397	// isn't an array.
398	if (E->isGLValue() && E->getType().isVolatileQualified() &&
399	!E->getType()->isArrayType()) {
400	S.Diag(Loc, DiagID: diag::warn_unused_volatile) << R1 << R2;
401	return;
402	}
403
404	// Do not diagnose use of a comma operator in a SFINAE context because the
405	// type of the left operand could be used for SFINAE, so technically it is
406	// *used*.
407	if (DiagID == diag::warn_unused_comma_left_operand && S.isSFINAEContext())
408	return;
409
410	S.DiagIfReachable(Loc, Stmts: llvm::ArrayRef<const Stmt *>(E),
411	PD: S.PDiag(DiagID: *DiagID) << R1 << R2);
412	}
413	} // namespace
414
415	void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
416	if (const LabelStmt *Label = dyn_cast_if_present<LabelStmt>(Val: S))
417	S = Label->getSubStmt();
418
419	const Expr *E = dyn_cast_if_present<Expr>(Val: S);
420	if (!E)
421	return;
422
423	DiagnoseUnused(S&: *this, E, DiagID);
424	}
425
426	void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
427	PushCompoundScope(IsStmtExpr);
428	}
429
430	void Sema::ActOnAfterCompoundStatementLeadingPragmas() {
431	if (getCurFPFeatures().isFPConstrained()) {
432	FunctionScopeInfo *FSI = getCurFunction();
433	assert(FSI);
434	FSI->setUsesFPIntrin();
435	}
436	}
437
438	void Sema::ActOnFinishOfCompoundStmt() {
439	PopCompoundScope();
440	}
441
442	sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
443	return getCurFunction()->CompoundScopes.back();
444	}
445
446	StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
447	ArrayRef<Stmt *> Elts, bool isStmtExpr) {
448	const unsigned NumElts = Elts.size();
449
450	// If we're in C mode, check that we don't have any decls after stmts. If
451	// so, emit an extension diagnostic in C89 and potentially a warning in later
452	// versions.
453	const unsigned MixedDeclsCodeID = getLangOpts().C99
454	? diag::warn_mixed_decls_code
455	: diag::ext_mixed_decls_code;
456	if (!getLangOpts().CPlusPlus && !Diags.isIgnored(DiagID: MixedDeclsCodeID, Loc: L)) {
457	// Note that __extension__ can be around a decl.
458	unsigned i = 0;
459	// Skip over all declarations.
460	for (; i != NumElts && isa<DeclStmt>(Val: Elts[i]); ++i)
461	/*empty*/;
462
463	// We found the end of the list or a statement. Scan for another declstmt.
464	for (; i != NumElts && !isa<DeclStmt>(Val: Elts[i]); ++i)
465	/*empty*/;
466
467	if (i != NumElts) {
468	Decl *D = *cast<DeclStmt>(Val: Elts[i])->decl_begin();
469	Diag(Loc: D->getLocation(), DiagID: MixedDeclsCodeID);
470	}
471	}
472
473	// Check for suspicious empty body (null statement) in `for' and `while'
474	// statements. Don't do anything for template instantiations, this just adds
475	// noise.
476	if (NumElts != 0 && !CurrentInstantiationScope &&
477	getCurCompoundScope().HasEmptyLoopBodies) {
478	for (unsigned i = 0; i != NumElts - 1; ++i)
479	DiagnoseEmptyLoopBody(S: Elts[i], PossibleBody: Elts[i + 1]);
480	}
481
482	// Calculate difference between FP options in this compound statement and in
483	// the enclosing one. If this is a function body, take the difference against
484	// default options. In this case the difference will indicate options that are
485	// changed upon entry to the statement.
486	FPOptions FPO = (getCurFunction()->CompoundScopes.size() == 1)
487	? FPOptions(getLangOpts())
488	: getCurCompoundScope().InitialFPFeatures;
489	FPOptionsOverride FPDiff = getCurFPFeatures().getChangesFrom(Base: FPO);
490
491	return CompoundStmt::Create(C: Context, Stmts: Elts, FPFeatures: FPDiff, LB: L, RB: R);
492	}
493
494	ExprResult
495	Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
496	if (!Val.get())
497	return Val;
498
499	if (DiagnoseUnexpandedParameterPack(E: Val.get()))
500	return ExprError();
501
502	// If we're not inside a switch, let the 'case' statement handling diagnose
503	// this. Just clean up after the expression as best we can.
504	if (getCurFunction()->SwitchStack.empty())
505	return ActOnFinishFullExpr(Expr: Val.get(), CC: Val.get()->getExprLoc(), DiscardedValue: false,
506	IsConstexpr: getLangOpts().CPlusPlus11);
507
508	Expr *CondExpr =
509	getCurFunction()->SwitchStack.back().getPointer()->getCond();
510	if (!CondExpr)
511	return ExprError();
512	QualType CondType = CondExpr->getType();
513
514	auto CheckAndFinish = [&](Expr *E) {
515	if (CondType->isDependentType() || E->isTypeDependent())
516	return ExprResult(E);
517
518	if (getLangOpts().CPlusPlus11) {
519	// C++11 [stmt.switch]p2: the constant-expression shall be a converted
520	// constant expression of the promoted type of the switch condition.
521	llvm::APSInt TempVal;
522	return CheckConvertedConstantExpression(From: E, T: CondType, Value&: TempVal,
523	CCE: CCEKind::CaseValue);
524	}
525
526	ExprResult ER = E;
527	if (!E->isValueDependent())
528	ER = VerifyIntegerConstantExpression(E, CanFold: AllowFoldKind::Allow);
529	if (!ER.isInvalid())
530	ER = DefaultLvalueConversion(E: ER.get());
531	if (!ER.isInvalid())
532	ER = ImpCastExprToType(E: ER.get(), Type: CondType, CK: CK_IntegralCast);
533	if (!ER.isInvalid())
534	ER = ActOnFinishFullExpr(Expr: ER.get(), CC: ER.get()->getExprLoc(), DiscardedValue: false);
535	return ER;
536	};
537
538	return CheckAndFinish(Val.get());
539	}
540
541	StmtResult
542	Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
543	SourceLocation DotDotDotLoc, ExprResult RHSVal,
544	SourceLocation ColonLoc) {
545	assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value");
546	assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()
547	: RHSVal.isInvalid() || RHSVal.get()) &&
548	"missing RHS value");
549
550	if (getCurFunction()->SwitchStack.empty()) {
551	Diag(Loc: CaseLoc, DiagID: diag::err_case_not_in_switch);
552	return StmtError();
553	}
554
555	if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
556	getCurFunction()->SwitchStack.back().setInt(true);
557	return StmtError();
558	}
559
560	if (LangOpts.OpenACC &&
561	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
562	Diag(Loc: CaseLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
563	<< /*branch*/ 0 << /*into*/ 1;
564	return StmtError();
565	}
566
567	auto *CS = CaseStmt::Create(Ctx: Context, lhs: LHSVal.get(), rhs: RHSVal.get(),
568	caseLoc: CaseLoc, ellipsisLoc: DotDotDotLoc, colonLoc: ColonLoc);
569	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: CS);
570	return CS;
571	}
572
573	void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
574	cast<CaseStmt>(Val: S)->setSubStmt(SubStmt);
575	}
576
577	StmtResult
578	Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
579	Stmt *SubStmt, Scope *CurScope) {
580	if (getCurFunction()->SwitchStack.empty()) {
581	Diag(Loc: DefaultLoc, DiagID: diag::err_default_not_in_switch);
582	return SubStmt;
583	}
584
585	if (LangOpts.OpenACC &&
586	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
587	Diag(Loc: DefaultLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
588	<< /*branch*/ 0 << /*into*/ 1;
589	return StmtError();
590	}
591
592	DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
593	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: DS);
594	return DS;
595	}
596
597	StmtResult
598	Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
599	SourceLocation ColonLoc, Stmt *SubStmt) {
600	// If the label was multiply defined, reject it now.
601	if (TheDecl->getStmt()) {
602	Diag(Loc: IdentLoc, DiagID: diag::err_redefinition_of_label) << TheDecl->getDeclName();
603	Diag(Loc: TheDecl->getLocation(), DiagID: diag::note_previous_definition);
604	return SubStmt;
605	}
606
607	ReservedIdentifierStatus Status = TheDecl->isReserved(LangOpts: getLangOpts());
608	if (isReservedInAllContexts(Status) &&
609	!Context.getSourceManager().isInSystemHeader(Loc: IdentLoc))
610	Diag(Loc: IdentLoc, DiagID: diag::warn_reserved_extern_symbol)
611	<< TheDecl << static_cast<int>(Status);
612
613	// If this label is in a compute construct scope, we need to make sure we
614	// check gotos in/out.
615	if (getCurScope()->isInOpenACCComputeConstructScope())
616	setFunctionHasBranchProtectedScope();
617
618	// OpenACC3.3 2.14.4:
619	// The update directive is executable. It must not appear in place of the
620	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
621	// C++.
622	if (isa<OpenACCUpdateConstruct>(Val: SubStmt)) {
623	Diag(Loc: SubStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*Label*/ 4;
624	SubStmt = new (Context) NullStmt(SubStmt->getBeginLoc());
625	}
626
627	// Otherwise, things are good. Fill in the declaration and return it.
628	LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
629	TheDecl->setStmt(LS);
630	if (!TheDecl->isGnuLocal()) {
631	TheDecl->setLocStart(IdentLoc);
632	if (!TheDecl->isMSAsmLabel()) {
633	// Don't update the location of MS ASM labels. These will result in
634	// a diagnostic, and changing the location here will mess that up.
635	TheDecl->setLocation(IdentLoc);
636	}
637	}
638	return LS;
639	}
640
641	StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
642	ArrayRef<const Attr *> Attrs,
643	Stmt *SubStmt) {
644	// FIXME: this code should move when a planned refactoring around statement
645	// attributes lands.
646	for (const auto *A : Attrs) {
647	if (A->getKind() == attr::MustTail) {
648	if (!checkAndRewriteMustTailAttr(St: SubStmt, MTA: *A)) {
649	return SubStmt;
650	}
651	setFunctionHasMustTail();
652	}
653	}
654
655	return AttributedStmt::Create(C: Context, Loc: AttrsLoc, Attrs, SubStmt);
656	}
657
658	StmtResult Sema::ActOnAttributedStmt(const ParsedAttributes &Attrs,
659	Stmt *SubStmt) {
660	SmallVector<const Attr *, 1> SemanticAttrs;
661	ProcessStmtAttributes(Stmt: SubStmt, InAttrs: Attrs, OutAttrs&: SemanticAttrs);
662	if (!SemanticAttrs.empty())
663	return BuildAttributedStmt(AttrsLoc: Attrs.Range.getBegin(), Attrs: SemanticAttrs, SubStmt);
664	// If none of the attributes applied, that's fine, we can recover by
665	// returning the substatement directly instead of making an AttributedStmt
666	// with no attributes on it.
667	return SubStmt;
668	}
669
670	bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
671	ReturnStmt *R = cast<ReturnStmt>(Val: St);
672	Expr *E = R->getRetValue();
673
674	if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
675	// We have to suspend our check until template instantiation time.
676	return true;
677
678	if (!checkMustTailAttr(St, MTA))
679	return false;
680
681	// FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
682	// Currently it does not skip implicit constructors in an initialization
683	// context.
684	auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
685	return IgnoreExprNodes(E, Fns&: IgnoreImplicitAsWrittenSingleStep,
686	Fns&: IgnoreElidableImplicitConstructorSingleStep);
687	};
688
689	// Now that we have verified that 'musttail' is valid here, rewrite the
690	// return value to remove all implicit nodes, but retain parentheses.
691	R->setRetValue(IgnoreImplicitAsWritten(E));
692	return true;
693	}
694
695	bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
696	assert(!CurContext->isDependentContext() &&
697	"musttail cannot be checked from a dependent context");
698
699	// FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
700	auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
701	return IgnoreExprNodes(E: const_cast<Expr *>(E), Fns&: IgnoreParensSingleStep,
702	Fns&: IgnoreImplicitAsWrittenSingleStep,
703	Fns&: IgnoreElidableImplicitConstructorSingleStep);
704	};
705
706	const Expr *E = cast<ReturnStmt>(Val: St)->getRetValue();
707	const auto *CE = dyn_cast_or_null<CallExpr>(Val: IgnoreParenImplicitAsWritten(E));
708
709	if (!CE) {
710	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_call) << &MTA;
711	return false;
712	}
713
714	if (const FunctionDecl *CalleeDecl = CE->getDirectCallee();
715	CalleeDecl && CalleeDecl->hasAttr<NotTailCalledAttr>()) {
716	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch) << /*show-function-callee=*/true << CalleeDecl;
717	Diag(Loc: CalleeDecl->getLocation(), DiagID: diag::note_musttail_disabled_by_not_tail_called);
718	return false;
719	}
720
721	if (const auto *EWC = dyn_cast<ExprWithCleanups>(Val: E)) {
722	if (EWC->cleanupsHaveSideEffects()) {
723	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_trivial_args) << &MTA;
724	return false;
725	}
726	}
727
728	// We need to determine the full function type (including "this" type, if any)
729	// for both caller and callee.
730	struct FuncType {
731	enum {
732	ft_non_member,
733	ft_static_member,
734	ft_non_static_member,
735	ft_pointer_to_member,
736	} MemberType = ft_non_member;
737
738	QualType This;
739	const FunctionProtoType *Func;
740	const CXXMethodDecl *Method = nullptr;
741	} CallerType, CalleeType;
742
743	auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
744	bool IsCallee) -> bool {
745	if (isa<CXXConstructorDecl, CXXDestructorDecl>(Val: CMD)) {
746	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_structors_forbidden)
747	<< IsCallee << isa<CXXDestructorDecl>(Val: CMD);
748	if (IsCallee)
749	Diag(Loc: CMD->getBeginLoc(), DiagID: diag::note_musttail_structors_forbidden)
750	<< isa<CXXDestructorDecl>(Val: CMD);
751	Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
752	return false;
753	}
754	if (CMD->isStatic())
755	Type.MemberType = FuncType::ft_static_member;
756	else {
757	Type.This = CMD->getFunctionObjectParameterType();
758	Type.MemberType = FuncType::ft_non_static_member;
759	}
760	Type.Func = CMD->getType()->castAs<FunctionProtoType>();
761	return true;
762	};
763
764	const auto *CallerDecl = dyn_cast<FunctionDecl>(Val: CurContext);
765
766	// Find caller function signature.
767	if (!CallerDecl) {
768	int ContextType;
769	if (isa<BlockDecl>(Val: CurContext))
770	ContextType = 0;
771	else if (isa<ObjCMethodDecl>(Val: CurContext))
772	ContextType = 1;
773	else
774	ContextType = 2;
775	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_forbidden_from_this_context)
776	<< &MTA << ContextType;
777	return false;
778	} else if (const auto *CMD = dyn_cast<CXXMethodDecl>(Val: CurContext)) {
779	// Caller is a class/struct method.
780	if (!GetMethodType(CMD, CallerType, false))
781	return false;
782	} else {
783	// Caller is a non-method function.
784	CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
785	}
786
787	const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
788	const auto *CalleeBinOp = dyn_cast<BinaryOperator>(Val: CalleeExpr);
789	SourceLocation CalleeLoc = CE->getCalleeDecl()
790	? CE->getCalleeDecl()->getBeginLoc()
791	: St->getBeginLoc();
792
793	// Find callee function signature.
794	if (const CXXMethodDecl *CMD =
795	dyn_cast_or_null<CXXMethodDecl>(Val: CE->getCalleeDecl())) {
796	// Call is: obj.method(), obj->method(), functor(), etc.
797	if (!GetMethodType(CMD, CalleeType, true))
798	return false;
799	} else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
800	// Call is: obj->*method_ptr or obj.*method_ptr
801	const auto *MPT =
802	CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
803	CalleeType.This =
804	Context.getTypeDeclType(Decl: MPT->getMostRecentCXXRecordDecl());
805	CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
806	CalleeType.MemberType = FuncType::ft_pointer_to_member;
807	} else if (isa<CXXPseudoDestructorExpr>(Val: CalleeExpr)) {
808	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_structors_forbidden)
809	<< /* IsCallee = */ 1 << /* IsDestructor = */ 1;
810	Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
811	return false;
812	} else {
813	// Non-method function.
814	CalleeType.Func =
815	CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
816	}
817
818	// Both caller and callee must have a prototype (no K&R declarations).
819	if (!CalleeType.Func || !CallerType.Func) {
820	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_needs_prototype) << &MTA;
821	if (!CalleeType.Func && CE->getDirectCallee()) {
822	Diag(Loc: CE->getDirectCallee()->getBeginLoc(),
823	DiagID: diag::note_musttail_fix_non_prototype);
824	}
825	if (!CallerType.Func)
826	Diag(Loc: CallerDecl->getBeginLoc(), DiagID: diag::note_musttail_fix_non_prototype);
827	return false;
828	}
829
830	// Caller and callee must have matching calling conventions.
831	//
832	// Some calling conventions are physically capable of supporting tail calls
833	// even if the function types don't perfectly match. LLVM is currently too
834	// strict to allow this, but if LLVM added support for this in the future, we
835	// could exit early here and skip the remaining checks if the functions are
836	// using such a calling convention.
837	if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
838	if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl()))
839	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_callconv_mismatch)
840	<< true << ND->getDeclName();
841	else
842	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_callconv_mismatch) << false;
843	Diag(Loc: CalleeLoc, DiagID: diag::note_musttail_callconv_mismatch)
844	<< FunctionType::getNameForCallConv(CC: CallerType.Func->getCallConv())
845	<< FunctionType::getNameForCallConv(CC: CalleeType.Func->getCallConv());
846	Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
847	return false;
848	}
849
850	if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
851	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_no_variadic) << &MTA;
852	return false;
853	}
854
855	const auto *CalleeDecl = CE->getCalleeDecl();
856	if (CalleeDecl && CalleeDecl->hasAttr<CXX11NoReturnAttr>()) {
857	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_no_return) << &MTA;
858	return false;
859	}
860
861	// Caller and callee must match in whether they have a "this" parameter.
862	if (CallerType.This.isNull() != CalleeType.This.isNull()) {
863	if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl())) {
864	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_member_mismatch)
865	<< CallerType.MemberType << CalleeType.MemberType << true
866	<< ND->getDeclName();
867	Diag(Loc: CalleeLoc, DiagID: diag::note_musttail_callee_defined_here)
868	<< ND->getDeclName();
869	} else
870	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_member_mismatch)
871	<< CallerType.MemberType << CalleeType.MemberType << false;
872	Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
873	return false;
874	}
875
876	auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
877	PartialDiagnostic &PD) -> bool {
878	enum {
879	ft_different_class,
880	ft_parameter_arity,
881	ft_parameter_mismatch,
882	ft_return_type,
883	};
884
885	auto DoTypesMatch = [this, &PD](QualType A, QualType B,
886	unsigned Select) -> bool {
887	if (!Context.hasSimilarType(T1: A, T2: B)) {
888	PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
889	return false;
890	}
891	return true;
892	};
893
894	if (!CallerType.This.isNull() &&
895	!DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
896	return false;
897
898	if (!DoTypesMatch(CallerType.Func->getReturnType(),
899	CalleeType.Func->getReturnType(), ft_return_type))
900	return false;
901
902	if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
903	PD << ft_parameter_arity << CallerType.Func->getNumParams()
904	<< CalleeType.Func->getNumParams();
905	return false;
906	}
907
908	ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
909	ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
910	size_t N = CallerType.Func->getNumParams();
911	for (size_t I = 0; I < N; I++) {
912	if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
913	ft_parameter_mismatch)) {
914	PD << static_cast<int>(I) + 1;
915	return false;
916	}
917	}
918
919	return true;
920	};
921
922	PartialDiagnostic PD = PDiag(DiagID: diag::note_musttail_mismatch);
923	if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
924	if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl()))
925	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch)
926	<< true << ND->getDeclName();
927	else
928	Diag(Loc: St->getBeginLoc(), DiagID: diag::err_musttail_mismatch) << false;
929	Diag(Loc: CalleeLoc, PD);
930	Diag(Loc: MTA.getLocation(), DiagID: diag::note_tail_call_required) << &MTA;
931	return false;
932	}
933
934	// The lifetimes of locals and incoming function parameters must end before
935	// the call, because we can't have a stack frame to store them, so diagnose
936	// any pointers or references to them passed into the musttail call.
937	for (auto ArgExpr : CE->arguments()) {
938	InitializedEntity Entity = InitializedEntity::InitializeParameter(
939	Context, Type: ArgExpr->getType(), Consumed: false);
940	checkExprLifetimeMustTailArg(SemaRef&: *this, Entity, Init: const_cast<Expr *>(ArgExpr));
941	}
942
943	return true;
944	}
945
946	namespace {
947	class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
948	typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
949	Sema &SemaRef;
950	public:
951	CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
952	void VisitBinaryOperator(BinaryOperator *E) {
953	if (E->getOpcode() == BO_Comma)
954	SemaRef.DiagnoseCommaOperator(LHS: E->getLHS(), Loc: E->getExprLoc());
955	EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(S: E);
956	}
957	};
958	}
959
960	StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc,
961	IfStatementKind StatementKind,
962	SourceLocation LParenLoc, Stmt *InitStmt,
963	ConditionResult Cond, SourceLocation RParenLoc,
964	Stmt *thenStmt, SourceLocation ElseLoc,
965	Stmt *elseStmt) {
966	if (Cond.isInvalid())
967	return StmtError();
968
969	bool ConstevalOrNegatedConsteval =
970	StatementKind == IfStatementKind::ConstevalNonNegated ||
971	StatementKind == IfStatementKind::ConstevalNegated;
972
973	Expr *CondExpr = Cond.get().second;
974	assert((CondExpr || ConstevalOrNegatedConsteval) &&
975	"If statement: missing condition");
976	// Only call the CommaVisitor when not C89 due to differences in scope flags.
977	if (CondExpr && (getLangOpts().C99 || getLangOpts().CPlusPlus) &&
978	!Diags.isIgnored(DiagID: diag::warn_comma_operator, Loc: CondExpr->getExprLoc()))
979	CommaVisitor(*this).Visit(S: CondExpr);
980
981	if (!ConstevalOrNegatedConsteval && !elseStmt)
982	DiagnoseEmptyStmtBody(StmtLoc: RParenLoc, Body: thenStmt, DiagID: diag::warn_empty_if_body);
983
984	if (ConstevalOrNegatedConsteval ||
985	StatementKind == IfStatementKind::Constexpr) {
986	auto DiagnoseLikelihood = [&](const Stmt *S) {
987	if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
988	Diags.Report(Loc: A->getLocation(),
989	DiagID: diag::warn_attribute_has_no_effect_on_compile_time_if)
990	<< A << ConstevalOrNegatedConsteval << A->getRange();
991	Diags.Report(Loc: IfLoc,
992	DiagID: diag::note_attribute_has_no_effect_on_compile_time_if_here)
993	<< ConstevalOrNegatedConsteval
994	<< SourceRange(IfLoc, (ConstevalOrNegatedConsteval
995	? thenStmt->getBeginLoc()
996	: LParenLoc)
997	.getLocWithOffset(Offset: -1));
998	}
999	};
1000	DiagnoseLikelihood(thenStmt);
1001	DiagnoseLikelihood(elseStmt);
1002	} else {
1003	std::tuple<bool, const Attr *, const Attr *> LHC =
1004	Stmt::determineLikelihoodConflict(Then: thenStmt, Else: elseStmt);
1005	if (std::get<0>(t&: LHC)) {
1006	const Attr *ThenAttr = std::get<1>(t&: LHC);
1007	const Attr *ElseAttr = std::get<2>(t&: LHC);
1008	Diags.Report(Loc: ThenAttr->getLocation(),
1009	DiagID: diag::warn_attributes_likelihood_ifstmt_conflict)
1010	<< ThenAttr << ThenAttr->getRange();
1011	Diags.Report(Loc: ElseAttr->getLocation(), DiagID: diag::note_conflicting_attribute)
1012	<< ElseAttr << ElseAttr->getRange();
1013	}
1014	}
1015
1016	if (ConstevalOrNegatedConsteval) {
1017	bool Immediate = ExprEvalContexts.back().Context ==
1018	ExpressionEvaluationContext::ImmediateFunctionContext;
1019	if (CurContext->isFunctionOrMethod()) {
1020	const auto *FD =
1021	dyn_cast<FunctionDecl>(Val: Decl::castFromDeclContext(CurContext));
1022	if (FD && FD->isImmediateFunction())
1023	Immediate = true;
1024	}
1025	if (isUnevaluatedContext() || Immediate)
1026	Diags.Report(Loc: IfLoc, DiagID: diag::warn_consteval_if_always_true) << Immediate;
1027	}
1028
1029	// OpenACC3.3 2.14.4:
1030	// The update directive is executable. It must not appear in place of the
1031	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1032	// C++.
1033	if (isa<OpenACCUpdateConstruct>(Val: thenStmt)) {
1034	Diag(Loc: thenStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*if*/ 0;
1035	thenStmt = new (Context) NullStmt(thenStmt->getBeginLoc());
1036	}
1037
1038	return BuildIfStmt(IfLoc, StatementKind, LParenLoc, InitStmt, Cond, RParenLoc,
1039	ThenVal: thenStmt, ElseLoc, ElseVal: elseStmt);
1040	}
1041
1042	StmtResult Sema::BuildIfStmt(SourceLocation IfLoc,
1043	IfStatementKind StatementKind,
1044	SourceLocation LParenLoc, Stmt *InitStmt,
1045	ConditionResult Cond, SourceLocation RParenLoc,
1046	Stmt *thenStmt, SourceLocation ElseLoc,
1047	Stmt *elseStmt) {
1048	if (Cond.isInvalid())
1049	return StmtError();
1050
1051	if (StatementKind != IfStatementKind::Ordinary ||
1052	isa<ObjCAvailabilityCheckExpr>(Val: Cond.get().second))
1053	setFunctionHasBranchProtectedScope();
1054
1055	return IfStmt::Create(Ctx: Context, IL: IfLoc, Kind: StatementKind, Init: InitStmt,
1056	Var: Cond.get().first, Cond: Cond.get().second, LPL: LParenLoc,
1057	RPL: RParenLoc, Then: thenStmt, EL: ElseLoc, Else: elseStmt);
1058	}
1059
1060	namespace {
1061	struct CaseCompareFunctor {
1062	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1063	const llvm::APSInt &RHS) {
1064	return LHS.first < RHS;
1065	}
1066	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1067	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1068	return LHS.first < RHS.first;
1069	}
1070	bool operator()(const llvm::APSInt &LHS,
1071	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1072	return LHS < RHS.first;
1073	}
1074	};
1075	}
1076
1077	/// CmpCaseVals - Comparison predicate for sorting case values.
1078	///
1079	static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
1080	const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
1081	if (lhs.first < rhs.first)
1082	return true;
1083
1084	if (lhs.first == rhs.first &&
1085	lhs.second->getCaseLoc() < rhs.second->getCaseLoc())
1086	return true;
1087	return false;
1088	}
1089
1090	/// CmpEnumVals - Comparison predicate for sorting enumeration values.
1091	///
1092	static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1093	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1094	{
1095	return lhs.first < rhs.first;
1096	}
1097
1098	/// EqEnumVals - Comparison preficate for uniqing enumeration values.
1099	///
1100	static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1101	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1102	{
1103	return lhs.first == rhs.first;
1104	}
1105
1106	/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
1107	/// potentially integral-promoted expression @p expr.
1108	static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
1109	if (const auto *FE = dyn_cast<FullExpr>(Val: E))
1110	E = FE->getSubExpr();
1111	while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(Val: E)) {
1112	if (ImpCast->getCastKind() != CK_IntegralCast) break;
1113	E = ImpCast->getSubExpr();
1114	}
1115	return E->getType();
1116	}
1117
1118	ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
1119	class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
1120	Expr *Cond;
1121
1122	public:
1123	SwitchConvertDiagnoser(Expr *Cond)
1124	: ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
1125	Cond(Cond) {}
1126
1127	SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
1128	QualType T) override {
1129	return S.Diag(Loc, DiagID: diag::err_typecheck_statement_requires_integer) << T;
1130	}
1131
1132	SemaDiagnosticBuilder diagnoseIncomplete(
1133	Sema &S, SourceLocation Loc, QualType T) override {
1134	return S.Diag(Loc, DiagID: diag::err_switch_incomplete_class_type)
1135	<< T << Cond->getSourceRange();
1136	}
1137
1138	SemaDiagnosticBuilder diagnoseExplicitConv(
1139	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1140	return S.Diag(Loc, DiagID: diag::err_switch_explicit_conversion) << T << ConvTy;
1141	}
1142
1143	SemaDiagnosticBuilder noteExplicitConv(
1144	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1145	return S.Diag(Loc: Conv->getLocation(), DiagID: diag::note_switch_conversion)
1146	<< ConvTy->isEnumeralType() << ConvTy;
1147	}
1148
1149	SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
1150	QualType T) override {
1151	return S.Diag(Loc, DiagID: diag::err_switch_multiple_conversions) << T;
1152	}
1153
1154	SemaDiagnosticBuilder noteAmbiguous(
1155	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1156	return S.Diag(Loc: Conv->getLocation(), DiagID: diag::note_switch_conversion)
1157	<< ConvTy->isEnumeralType() << ConvTy;
1158	}
1159
1160	SemaDiagnosticBuilder diagnoseConversion(
1161	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1162	llvm_unreachable("conversion functions are permitted");
1163	}
1164	} SwitchDiagnoser(Cond);
1165
1166	ExprResult CondResult =
1167	PerformContextualImplicitConversion(Loc: SwitchLoc, FromE: Cond, Converter&: SwitchDiagnoser);
1168	if (CondResult.isInvalid())
1169	return ExprError();
1170
1171	// FIXME: PerformContextualImplicitConversion doesn't always tell us if it
1172	// failed and produced a diagnostic.
1173	Cond = CondResult.get();
1174	if (!Cond->isTypeDependent() &&
1175	!Cond->getType()->isIntegralOrEnumerationType())
1176	return ExprError();
1177
1178	// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
1179	return UsualUnaryConversions(E: Cond);
1180	}
1181
1182	StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
1183	SourceLocation LParenLoc,
1184	Stmt *InitStmt, ConditionResult Cond,
1185	SourceLocation RParenLoc) {
1186	Expr *CondExpr = Cond.get().second;
1187	assert((Cond.isInvalid() || CondExpr) && "switch with no condition");
1188
1189	if (CondExpr && !CondExpr->isTypeDependent()) {
1190	// We have already converted the expression to an integral or enumeration
1191	// type, when we parsed the switch condition. There are cases where we don't
1192	// have an appropriate type, e.g. a typo-expr Cond was corrected to an
1193	// inappropriate-type expr, we just return an error.
1194	if (!CondExpr->getType()->isIntegralOrEnumerationType())
1195	return StmtError();
1196	if (CondExpr->isKnownToHaveBooleanValue()) {
1197	// switch(bool_expr) {...} is often a programmer error, e.g.
1198	// switch(n && mask) { ... } // Doh - should be "n & mask".
1199	// One can always use an if statement instead of switch(bool_expr).
1200	Diag(Loc: SwitchLoc, DiagID: diag::warn_bool_switch_condition)
1201	<< CondExpr->getSourceRange();
1202	}
1203	}
1204
1205	setFunctionHasBranchIntoScope();
1206
1207	auto *SS = SwitchStmt::Create(Ctx: Context, Init: InitStmt, Var: Cond.get().first, Cond: CondExpr,
1208	LParenLoc, RParenLoc);
1209	getCurFunction()->SwitchStack.push_back(
1210	Elt: FunctionScopeInfo::SwitchInfo(SS, false));
1211	return SS;
1212	}
1213
1214	static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
1215	Val = Val.extOrTrunc(width: BitWidth);
1216	Val.setIsSigned(IsSigned);
1217	}
1218
1219	/// Check the specified case value is in range for the given unpromoted switch
1220	/// type.
1221	static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
1222	unsigned UnpromotedWidth, bool UnpromotedSign) {
1223	// In C++11 onwards, this is checked by the language rules.
1224	if (S.getLangOpts().CPlusPlus11)
1225	return;
1226
1227	// If the case value was signed and negative and the switch expression is
1228	// unsigned, don't bother to warn: this is implementation-defined behavior.
1229	// FIXME: Introduce a second, default-ignored warning for this case?
1230	if (UnpromotedWidth < Val.getBitWidth()) {
1231	llvm::APSInt ConvVal(Val);
1232	AdjustAPSInt(Val&: ConvVal, BitWidth: UnpromotedWidth, IsSigned: UnpromotedSign);
1233	AdjustAPSInt(Val&: ConvVal, BitWidth: Val.getBitWidth(), IsSigned: Val.isSigned());
1234	// FIXME: Use different diagnostics for overflow in conversion to promoted
1235	// type versus "switch expression cannot have this value". Use proper
1236	// IntRange checking rather than just looking at the unpromoted type here.
1237	if (ConvVal != Val)
1238	S.Diag(Loc, DiagID: diag::warn_case_value_overflow) << toString(I: Val, Radix: 10)
1239	<< toString(I: ConvVal, Radix: 10);
1240	}
1241	}
1242
1243	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
1244
1245	/// Returns true if we should emit a diagnostic about this case expression not
1246	/// being a part of the enum used in the switch controlling expression.
1247	static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
1248	const EnumDecl *ED,
1249	const Expr *CaseExpr,
1250	EnumValsTy::iterator &EI,
1251	EnumValsTy::iterator &EIEnd,
1252	const llvm::APSInt &Val) {
1253	if (!ED->isClosed())
1254	return false;
1255
1256	if (const DeclRefExpr *DRE =
1257	dyn_cast<DeclRefExpr>(Val: CaseExpr->IgnoreParenImpCasts())) {
1258	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: DRE->getDecl())) {
1259	QualType VarType = VD->getType();
1260	QualType EnumType = S.Context.getTypeDeclType(Decl: ED);
1261	if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
1262	S.Context.hasSameUnqualifiedType(T1: EnumType, T2: VarType))
1263	return false;
1264	}
1265	}
1266
1267	if (ED->hasAttr<FlagEnumAttr>())
1268	return !S.IsValueInFlagEnum(ED, Val, AllowMask: false);
1269
1270	while (EI != EIEnd && EI->first < Val)
1271	EI++;
1272
1273	if (EI != EIEnd && EI->first == Val)
1274	return false;
1275
1276	return true;
1277	}
1278
1279	static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
1280	const Expr *Case) {
1281	QualType CondType = Cond->getType();
1282	QualType CaseType = Case->getType();
1283
1284	const EnumType *CondEnumType = CondType->getAs<EnumType>();
1285	const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
1286	if (!CondEnumType || !CaseEnumType)
1287	return;
1288
1289	// Ignore anonymous enums.
1290	if (!CondEnumType->getDecl()->getIdentifier() &&
1291	!CondEnumType->getDecl()->getTypedefNameForAnonDecl())
1292	return;
1293	if (!CaseEnumType->getDecl()->getIdentifier() &&
1294	!CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
1295	return;
1296
1297	if (S.Context.hasSameUnqualifiedType(T1: CondType, T2: CaseType))
1298	return;
1299
1300	S.Diag(Loc: Case->getExprLoc(), DiagID: diag::warn_comparison_of_mixed_enum_types_switch)
1301	<< CondType << CaseType << Cond->getSourceRange()
1302	<< Case->getSourceRange();
1303	}
1304
1305	StmtResult
1306	Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
1307	Stmt *BodyStmt) {
1308	SwitchStmt *SS = cast<SwitchStmt>(Val: Switch);
1309	bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
1310	assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&
1311	"switch stack missing push/pop!");
1312
1313	getCurFunction()->SwitchStack.pop_back();
1314
1315	if (!BodyStmt) return StmtError();
1316
1317	// OpenACC3.3 2.14.4:
1318	// The update directive is executable. It must not appear in place of the
1319	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1320	// C++.
1321	if (isa<OpenACCUpdateConstruct>(Val: BodyStmt)) {
1322	Diag(Loc: BodyStmt->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*switch*/ 3;
1323	BodyStmt = new (Context) NullStmt(BodyStmt->getBeginLoc());
1324	}
1325
1326	SS->setBody(S: BodyStmt, SL: SwitchLoc);
1327
1328	Expr *CondExpr = SS->getCond();
1329	if (!CondExpr) return StmtError();
1330
1331	QualType CondType = CondExpr->getType();
1332
1333	// C++ 6.4.2.p2:
1334	// Integral promotions are performed (on the switch condition).
1335	//
1336	// A case value unrepresentable by the original switch condition
1337	// type (before the promotion) doesn't make sense, even when it can
1338	// be represented by the promoted type. Therefore we need to find
1339	// the pre-promotion type of the switch condition.
1340	const Expr *CondExprBeforePromotion = CondExpr;
1341	QualType CondTypeBeforePromotion =
1342	GetTypeBeforeIntegralPromotion(E&: CondExprBeforePromotion);
1343
1344	// Get the bitwidth of the switched-on value after promotions. We must
1345	// convert the integer case values to this width before comparison.
1346	bool HasDependentValue
1347	= CondExpr->isTypeDependent() || CondExpr->isValueDependent();
1348	unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(T: CondType);
1349	bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
1350
1351	// Get the width and signedness that the condition might actually have, for
1352	// warning purposes.
1353	// FIXME: Grab an IntRange for the condition rather than using the unpromoted
1354	// type.
1355	unsigned CondWidthBeforePromotion
1356	= HasDependentValue ? 0 : Context.getIntWidth(T: CondTypeBeforePromotion);
1357	bool CondIsSignedBeforePromotion
1358	= CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
1359
1360	// Accumulate all of the case values in a vector so that we can sort them
1361	// and detect duplicates. This vector contains the APInt for the case after
1362	// it has been converted to the condition type.
1363	typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
1364	CaseValsTy CaseVals;
1365
1366	// Keep track of any GNU case ranges we see. The APSInt is the low value.
1367	typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
1368	CaseRangesTy CaseRanges;
1369
1370	DefaultStmt *TheDefaultStmt = nullptr;
1371
1372	bool CaseListIsErroneous = false;
1373
1374	// FIXME: We'd better diagnose missing or duplicate default labels even
1375	// in the dependent case. Because default labels themselves are never
1376	// dependent.
1377	for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
1378	SC = SC->getNextSwitchCase()) {
1379
1380	if (DefaultStmt *DS = dyn_cast<DefaultStmt>(Val: SC)) {
1381	if (TheDefaultStmt) {
1382	Diag(Loc: DS->getDefaultLoc(), DiagID: diag::err_multiple_default_labels_defined);
1383	Diag(Loc: TheDefaultStmt->getDefaultLoc(), DiagID: diag::note_duplicate_case_prev);
1384
1385	// FIXME: Remove the default statement from the switch block so that
1386	// we'll return a valid AST. This requires recursing down the AST and
1387	// finding it, not something we are set up to do right now. For now,
1388	// just lop the entire switch stmt out of the AST.
1389	CaseListIsErroneous = true;
1390	}
1391	TheDefaultStmt = DS;
1392
1393	} else {
1394	CaseStmt *CS = cast<CaseStmt>(Val: SC);
1395
1396	Expr *Lo = CS->getLHS();
1397
1398	if (Lo->isValueDependent()) {
1399	HasDependentValue = true;
1400	break;
1401	}
1402
1403	// We already verified that the expression has a constant value;
1404	// get that value (prior to conversions).
1405	const Expr *LoBeforePromotion = Lo;
1406	GetTypeBeforeIntegralPromotion(E&: LoBeforePromotion);
1407	llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1408
1409	// Check the unconverted value is within the range of possible values of
1410	// the switch expression.
1411	checkCaseValue(S&: *this, Loc: Lo->getBeginLoc(), Val: LoVal, UnpromotedWidth: CondWidthBeforePromotion,
1412	UnpromotedSign: CondIsSignedBeforePromotion);
1413
1414	// FIXME: This duplicates the check performed for warn_not_in_enum below.
1415	checkEnumTypesInSwitchStmt(S&: *this, Cond: CondExprBeforePromotion,
1416	Case: LoBeforePromotion);
1417
1418	// Convert the value to the same width/sign as the condition.
1419	AdjustAPSInt(Val&: LoVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1420
1421	// If this is a case range, remember it in CaseRanges, otherwise CaseVals.
1422	if (CS->getRHS()) {
1423	if (CS->getRHS()->isValueDependent()) {
1424	HasDependentValue = true;
1425	break;
1426	}
1427	CaseRanges.push_back(x: std::make_pair(x&: LoVal, y&: CS));
1428	} else
1429	CaseVals.push_back(Elt: std::make_pair(x&: LoVal, y&: CS));
1430	}
1431	}
1432
1433	if (!HasDependentValue) {
1434	// If we don't have a default statement, check whether the
1435	// condition is constant.
1436	llvm::APSInt ConstantCondValue;
1437	bool HasConstantCond = false;
1438	if (!TheDefaultStmt) {
1439	Expr::EvalResult Result;
1440	HasConstantCond = CondExpr->EvaluateAsInt(Result, Ctx: Context,
1441	AllowSideEffects: Expr::SE_AllowSideEffects);
1442	if (Result.Val.isInt())
1443	ConstantCondValue = Result.Val.getInt();
1444	assert(!HasConstantCond ||
1445	(ConstantCondValue.getBitWidth() == CondWidth &&
1446	ConstantCondValue.isSigned() == CondIsSigned));
1447	Diag(Loc: SwitchLoc, DiagID: diag::warn_switch_default);
1448	}
1449	bool ShouldCheckConstantCond = HasConstantCond;
1450
1451	// Sort all the scalar case values so we can easily detect duplicates.
1452	llvm::stable_sort(Range&: CaseVals, C: CmpCaseVals);
1453
1454	if (!CaseVals.empty()) {
1455	for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
1456	if (ShouldCheckConstantCond &&
1457	CaseVals[i].first == ConstantCondValue)
1458	ShouldCheckConstantCond = false;
1459
1460	if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
1461	// If we have a duplicate, report it.
1462	// First, determine if either case value has a name
1463	StringRef PrevString, CurrString;
1464	Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
1465	Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
1466	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: PrevCase)) {
1467	PrevString = DeclRef->getDecl()->getName();
1468	}
1469	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: CurrCase)) {
1470	CurrString = DeclRef->getDecl()->getName();
1471	}
1472	SmallString<16> CaseValStr;
1473	CaseVals[i-1].first.toString(Str&: CaseValStr);
1474
1475	if (PrevString == CurrString)
1476	Diag(Loc: CaseVals[i].second->getLHS()->getBeginLoc(),
1477	DiagID: diag::err_duplicate_case)
1478	<< (PrevString.empty() ? CaseValStr.str() : PrevString);
1479	else
1480	Diag(Loc: CaseVals[i].second->getLHS()->getBeginLoc(),
1481	DiagID: diag::err_duplicate_case_differing_expr)
1482	<< (PrevString.empty() ? CaseValStr.str() : PrevString)
1483	<< (CurrString.empty() ? CaseValStr.str() : CurrString)
1484	<< CaseValStr;
1485
1486	Diag(Loc: CaseVals[i - 1].second->getLHS()->getBeginLoc(),
1487	DiagID: diag::note_duplicate_case_prev);
1488	// FIXME: We really want to remove the bogus case stmt from the
1489	// substmt, but we have no way to do this right now.
1490	CaseListIsErroneous = true;
1491	}
1492	}
1493	}
1494
1495	// Detect duplicate case ranges, which usually don't exist at all in
1496	// the first place.
1497	if (!CaseRanges.empty()) {
1498	// Sort all the case ranges by their low value so we can easily detect
1499	// overlaps between ranges.
1500	llvm::stable_sort(Range&: CaseRanges);
1501
1502	// Scan the ranges, computing the high values and removing empty ranges.
1503	std::vector<llvm::APSInt> HiVals;
1504	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1505	llvm::APSInt &LoVal = CaseRanges[i].first;
1506	CaseStmt *CR = CaseRanges[i].second;
1507	Expr *Hi = CR->getRHS();
1508
1509	const Expr *HiBeforePromotion = Hi;
1510	GetTypeBeforeIntegralPromotion(E&: HiBeforePromotion);
1511	llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1512
1513	// Check the unconverted value is within the range of possible values of
1514	// the switch expression.
1515	checkCaseValue(S&: *this, Loc: Hi->getBeginLoc(), Val: HiVal,
1516	UnpromotedWidth: CondWidthBeforePromotion, UnpromotedSign: CondIsSignedBeforePromotion);
1517
1518	// Convert the value to the same width/sign as the condition.
1519	AdjustAPSInt(Val&: HiVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1520
1521	// If the low value is bigger than the high value, the case is empty.
1522	if (LoVal > HiVal) {
1523	Diag(Loc: CR->getLHS()->getBeginLoc(), DiagID: diag::warn_case_empty_range)
1524	<< SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
1525	CaseRanges.erase(position: CaseRanges.begin()+i);
1526	--i;
1527	--e;
1528	continue;
1529	}
1530
1531	if (ShouldCheckConstantCond &&
1532	LoVal <= ConstantCondValue &&
1533	ConstantCondValue <= HiVal)
1534	ShouldCheckConstantCond = false;
1535
1536	HiVals.push_back(x: HiVal);
1537	}
1538
1539	// Rescan the ranges, looking for overlap with singleton values and other
1540	// ranges. Since the range list is sorted, we only need to compare case
1541	// ranges with their neighbors.
1542	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1543	llvm::APSInt &CRLo = CaseRanges[i].first;
1544	llvm::APSInt &CRHi = HiVals[i];
1545	CaseStmt *CR = CaseRanges[i].second;
1546
1547	// Check to see whether the case range overlaps with any
1548	// singleton cases.
1549	CaseStmt *OverlapStmt = nullptr;
1550	llvm::APSInt OverlapVal(32);
1551
1552	// Find the smallest value >= the lower bound. If I is in the
1553	// case range, then we have overlap.
1554	CaseValsTy::iterator I =
1555	llvm::lower_bound(Range&: CaseVals, Value&: CRLo, C: CaseCompareFunctor());
1556	if (I != CaseVals.end() && I->first < CRHi) {
1557	OverlapVal = I->first; // Found overlap with scalar.
1558	OverlapStmt = I->second;
1559	}
1560
1561	// Find the smallest value bigger than the upper bound.
1562	I = std::upper_bound(first: I, last: CaseVals.end(), val: CRHi, comp: CaseCompareFunctor());
1563	if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1564	OverlapVal = (I-1)->first; // Found overlap with scalar.
1565	OverlapStmt = (I-1)->second;
1566	}
1567
1568	// Check to see if this case stmt overlaps with the subsequent
1569	// case range.
1570	if (i && CRLo <= HiVals[i-1]) {
1571	OverlapVal = HiVals[i-1]; // Found overlap with range.
1572	OverlapStmt = CaseRanges[i-1].second;
1573	}
1574
1575	if (OverlapStmt) {
1576	// If we have a duplicate, report it.
1577	Diag(Loc: CR->getLHS()->getBeginLoc(), DiagID: diag::err_duplicate_case)
1578	<< toString(I: OverlapVal, Radix: 10);
1579	Diag(Loc: OverlapStmt->getLHS()->getBeginLoc(),
1580	DiagID: diag::note_duplicate_case_prev);
1581	// FIXME: We really want to remove the bogus case stmt from the
1582	// substmt, but we have no way to do this right now.
1583	CaseListIsErroneous = true;
1584	}
1585	}
1586	}
1587
1588	// Complain if we have a constant condition and we didn't find a match.
1589	if (!CaseListIsErroneous && !CaseListIsIncomplete &&
1590	ShouldCheckConstantCond) {
1591	// TODO: it would be nice if we printed enums as enums, chars as
1592	// chars, etc.
1593	Diag(Loc: CondExpr->getExprLoc(), DiagID: diag::warn_missing_case_for_condition)
1594	<< toString(I: ConstantCondValue, Radix: 10)
1595	<< CondExpr->getSourceRange();
1596	}
1597
1598	// Check to see if switch is over an Enum and handles all of its
1599	// values. We only issue a warning if there is not 'default:', but
1600	// we still do the analysis to preserve this information in the AST
1601	// (which can be used by flow-based analyes).
1602	//
1603	const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1604
1605	// If switch has default case, then ignore it.
1606	if (!CaseListIsErroneous && !CaseListIsIncomplete && !HasConstantCond &&
1607	ET && ET->getDecl()->isCompleteDefinition() &&
1608	!ET->getDecl()->enumerators().empty()) {
1609	const EnumDecl *ED = ET->getDecl();
1610	EnumValsTy EnumVals;
1611
1612	// Gather all enum values, set their type and sort them,
1613	// allowing easier comparison with CaseVals.
1614	for (auto *EDI : ED->enumerators()) {
1615	llvm::APSInt Val = EDI->getInitVal();
1616	AdjustAPSInt(Val, BitWidth: CondWidth, IsSigned: CondIsSigned);
1617	EnumVals.push_back(Elt: std::make_pair(x&: Val, y&: EDI));
1618	}
1619	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1620	auto EI = EnumVals.begin(), EIEnd = llvm::unique(R&: EnumVals, P: EqEnumVals);
1621
1622	// See which case values aren't in enum.
1623	for (CaseValsTy::const_iterator CI = CaseVals.begin();
1624	CI != CaseVals.end(); CI++) {
1625	Expr *CaseExpr = CI->second->getLHS();
1626	if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1627	Val: CI->first))
1628	Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1629	<< CondTypeBeforePromotion;
1630	}
1631
1632	// See which of case ranges aren't in enum
1633	EI = EnumVals.begin();
1634	for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1635	RI != CaseRanges.end(); RI++) {
1636	Expr *CaseExpr = RI->second->getLHS();
1637	if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1638	Val: RI->first))
1639	Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1640	<< CondTypeBeforePromotion;
1641
1642	llvm::APSInt Hi =
1643	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1644	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1645
1646	CaseExpr = RI->second->getRHS();
1647	if (ShouldDiagnoseSwitchCaseNotInEnum(S: *this, ED, CaseExpr, EI, EIEnd,
1648	Val: Hi))
1649	Diag(Loc: CaseExpr->getExprLoc(), DiagID: diag::warn_not_in_enum)
1650	<< CondTypeBeforePromotion;
1651	}
1652
1653	// Check which enum vals aren't in switch
1654	auto CI = CaseVals.begin();
1655	auto RI = CaseRanges.begin();
1656	bool hasCasesNotInSwitch = false;
1657
1658	SmallVector<DeclarationName,8> UnhandledNames;
1659
1660	for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
1661	// Don't warn about omitted unavailable EnumConstantDecls.
1662	switch (EI->second->getAvailability()) {
1663	case AR_Deprecated:
1664	// Deprecated enumerators need to be handled: they may be deprecated,
1665	// but can still occur.
1666	break;
1667
1668	case AR_Unavailable:
1669	// Omitting an unavailable enumerator is ok; it should never occur.
1670	continue;
1671
1672	case AR_NotYetIntroduced:
1673	// Partially available enum constants should be present. Note that we
1674	// suppress -Wunguarded-availability diagnostics for such uses.
1675	case AR_Available:
1676	break;
1677	}
1678
1679	if (EI->second->hasAttr<UnusedAttr>())
1680	continue;
1681
1682	// Drop unneeded case values
1683	while (CI != CaseVals.end() && CI->first < EI->first)
1684	CI++;
1685
1686	if (CI != CaseVals.end() && CI->first == EI->first)
1687	continue;
1688
1689	// Drop unneeded case ranges
1690	for (; RI != CaseRanges.end(); RI++) {
1691	llvm::APSInt Hi =
1692	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1693	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1694	if (EI->first <= Hi)
1695	break;
1696	}
1697
1698	if (RI == CaseRanges.end() || EI->first < RI->first) {
1699	hasCasesNotInSwitch = true;
1700	UnhandledNames.push_back(Elt: EI->second->getDeclName());
1701	}
1702	}
1703
1704	if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1705	Diag(Loc: TheDefaultStmt->getDefaultLoc(), DiagID: diag::warn_unreachable_default);
1706
1707	// Produce a nice diagnostic if multiple values aren't handled.
1708	if (!UnhandledNames.empty()) {
1709	auto DB = Diag(Loc: CondExpr->getExprLoc(), DiagID: TheDefaultStmt
1710	? diag::warn_def_missing_case
1711	: diag::warn_missing_case)
1712	<< CondExpr->getSourceRange() << (int)UnhandledNames.size();
1713
1714	for (size_t I = 0, E = std::min(a: UnhandledNames.size(), b: (size_t)3);
1715	I != E; ++I)
1716	DB << UnhandledNames[I];
1717	}
1718
1719	if (!hasCasesNotInSwitch)
1720	SS->setAllEnumCasesCovered();
1721	}
1722	}
1723
1724	if (BodyStmt)
1725	DiagnoseEmptyStmtBody(StmtLoc: CondExpr->getEndLoc(), Body: BodyStmt,
1726	DiagID: diag::warn_empty_switch_body);
1727
1728	// FIXME: If the case list was broken is some way, we don't have a good system
1729	// to patch it up. Instead, just return the whole substmt as broken.
1730	if (CaseListIsErroneous)
1731	return StmtError();
1732
1733	return SS;
1734	}
1735
1736	void
1737	Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1738	Expr *SrcExpr) {
1739
1740	const auto *ET = DstType->getAs<EnumType>();
1741	if (!ET)
1742	return;
1743
1744	if (!SrcType->isIntegerType() ||
1745	Context.hasSameUnqualifiedType(T1: SrcType, T2: DstType))
1746	return;
1747
1748	if (SrcExpr->isTypeDependent() || SrcExpr->isValueDependent())
1749	return;
1750
1751	const EnumDecl *ED = ET->getDecl();
1752	if (!ED->isClosed())
1753	return;
1754
1755	if (Diags.isIgnored(DiagID: diag::warn_not_in_enum_assignment, Loc: SrcExpr->getExprLoc()))
1756	return;
1757
1758	std::optional<llvm::APSInt> RHSVal = SrcExpr->getIntegerConstantExpr(Ctx: Context);
1759	if (!RHSVal)
1760	return;
1761
1762	// Get the bitwidth of the enum value before promotions.
1763	unsigned DstWidth = Context.getIntWidth(T: DstType);
1764	bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1765	AdjustAPSInt(Val&: *RHSVal, BitWidth: DstWidth, IsSigned: DstIsSigned);
1766
1767	if (ED->hasAttr<FlagEnumAttr>()) {
1768	if (!IsValueInFlagEnum(ED, Val: *RHSVal, /*AllowMask=*/true))
1769	Diag(Loc: SrcExpr->getExprLoc(), DiagID: diag::warn_not_in_enum_assignment)
1770	<< DstType.getUnqualifiedType();
1771	return;
1772	}
1773
1774	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1775	EnumValsTy;
1776	EnumValsTy EnumVals;
1777
1778	// Gather all enum values, set their type and sort them,
1779	// allowing easier comparison with rhs constant.
1780	for (auto *EDI : ED->enumerators()) {
1781	llvm::APSInt Val = EDI->getInitVal();
1782	AdjustAPSInt(Val, BitWidth: DstWidth, IsSigned: DstIsSigned);
1783	EnumVals.emplace_back(Args&: Val, Args&: EDI);
1784	}
1785	if (EnumVals.empty())
1786	return;
1787	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1788	EnumValsTy::iterator EIend = llvm::unique(R&: EnumVals, P: EqEnumVals);
1789
1790	// See which values aren't in the enum.
1791	EnumValsTy::const_iterator EI = EnumVals.begin();
1792	while (EI != EIend && EI->first < *RHSVal)
1793	EI++;
1794	if (EI == EIend || EI->first != *RHSVal) {
1795	Diag(Loc: SrcExpr->getExprLoc(), DiagID: diag::warn_not_in_enum_assignment)
1796	<< DstType.getUnqualifiedType();
1797	}
1798	}
1799
1800	StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
1801	SourceLocation LParenLoc, ConditionResult Cond,
1802	SourceLocation RParenLoc, Stmt *Body) {
1803	if (Cond.isInvalid())
1804	return StmtError();
1805
1806	auto CondVal = Cond.get();
1807	CheckBreakContinueBinding(E: CondVal.second);
1808
1809	if (CondVal.second &&
1810	!Diags.isIgnored(DiagID: diag::warn_comma_operator, Loc: CondVal.second->getExprLoc()))
1811	CommaVisitor(*this).Visit(S: CondVal.second);
1812
1813	// OpenACC3.3 2.14.4:
1814	// The update directive is executable. It must not appear in place of the
1815	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1816	// C++.
1817	if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1818	Diag(Loc: Body->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*while*/ 1;
1819	Body = new (Context) NullStmt(Body->getBeginLoc());
1820	}
1821
1822	if (isa<NullStmt>(Val: Body))
1823	getCurCompoundScope().setHasEmptyLoopBodies();
1824
1825	return WhileStmt::Create(Ctx: Context, Var: CondVal.first, Cond: CondVal.second, Body,
1826	WL: WhileLoc, LParenLoc, RParenLoc);
1827	}
1828
1829	StmtResult
1830	Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1831	SourceLocation WhileLoc, SourceLocation CondLParen,
1832	Expr *Cond, SourceLocation CondRParen) {
1833	assert(Cond && "ActOnDoStmt(): missing expression");
1834
1835	CheckBreakContinueBinding(E: Cond);
1836	ExprResult CondResult = CheckBooleanCondition(Loc: DoLoc, E: Cond);
1837	if (CondResult.isInvalid())
1838	return StmtError();
1839	Cond = CondResult.get();
1840
1841	CondResult = ActOnFinishFullExpr(Expr: Cond, CC: DoLoc, /*DiscardedValue*/ false);
1842	if (CondResult.isInvalid())
1843	return StmtError();
1844	Cond = CondResult.get();
1845
1846	// Only call the CommaVisitor for C89 due to differences in scope flags.
1847	if (Cond && !getLangOpts().C99 && !getLangOpts().CPlusPlus &&
1848	!Diags.isIgnored(DiagID: diag::warn_comma_operator, Loc: Cond->getExprLoc()))
1849	CommaVisitor(*this).Visit(S: Cond);
1850
1851	// OpenACC3.3 2.14.4:
1852	// The update directive is executable. It must not appear in place of the
1853	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1854	// C++.
1855	if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1856	Diag(Loc: Body->getBeginLoc(), DiagID: diag::err_acc_update_as_body) << /*do*/ 2;
1857	Body = new (Context) NullStmt(Body->getBeginLoc());
1858	}
1859
1860	return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1861	}
1862
1863	namespace {
1864	// Use SetVector since the diagnostic cares about the ordering of the Decl's.
1865	using DeclSetVector = llvm::SmallSetVector<VarDecl *, 8>;
1866
1867	// This visitor will traverse a conditional statement and store all
1868	// the evaluated decls into a vector. Simple is set to true if none
1869	// of the excluded constructs are used.
1870	class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1871	DeclSetVector &Decls;
1872	SmallVectorImpl<SourceRange> &Ranges;
1873	bool Simple;
1874	public:
1875	typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1876
1877	DeclExtractor(Sema &S, DeclSetVector &Decls,
1878	SmallVectorImpl<SourceRange> &Ranges) :
1879	Inherited(S.Context),
1880	Decls(Decls),
1881	Ranges(Ranges),
1882	Simple(true) {}
1883
1884	bool isSimple() { return Simple; }
1885
1886	// Replaces the method in EvaluatedExprVisitor.
1887	void VisitMemberExpr(MemberExpr* E) {
1888	Simple = false;
1889	}
1890
1891	// Any Stmt not explicitly listed will cause the condition to be marked
1892	// complex.
1893	void VisitStmt(Stmt *S) { Simple = false; }
1894
1895	void VisitBinaryOperator(BinaryOperator *E) {
1896	Visit(S: E->getLHS());
1897	Visit(S: E->getRHS());
1898	}
1899
1900	void VisitCastExpr(CastExpr *E) {
1901	Visit(S: E->getSubExpr());
1902	}
1903
1904	void VisitUnaryOperator(UnaryOperator *E) {
1905	// Skip checking conditionals with derefernces.
1906	if (E->getOpcode() == UO_Deref)
1907	Simple = false;
1908	else
1909	Visit(S: E->getSubExpr());
1910	}
1911
1912	void VisitConditionalOperator(ConditionalOperator *E) {
1913	Visit(S: E->getCond());
1914	Visit(S: E->getTrueExpr());
1915	Visit(S: E->getFalseExpr());
1916	}
1917
1918	void VisitParenExpr(ParenExpr *E) {
1919	Visit(S: E->getSubExpr());
1920	}
1921
1922	void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1923	Visit(S: E->getOpaqueValue()->getSourceExpr());
1924	Visit(S: E->getFalseExpr());
1925	}
1926
1927	void VisitIntegerLiteral(IntegerLiteral *E) { }
1928	void VisitFloatingLiteral(FloatingLiteral *E) { }
1929	void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1930	void VisitCharacterLiteral(CharacterLiteral *E) { }
1931	void VisitGNUNullExpr(GNUNullExpr *E) { }
1932	void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1933
1934	void VisitDeclRefExpr(DeclRefExpr *E) {
1935	VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl());
1936	if (!VD) {
1937	// Don't allow unhandled Decl types.
1938	Simple = false;
1939	return;
1940	}
1941
1942	Ranges.push_back(Elt: E->getSourceRange());
1943
1944	Decls.insert(X: VD);
1945	}
1946
1947	}; // end class DeclExtractor
1948
1949	// DeclMatcher checks to see if the decls are used in a non-evaluated
1950	// context.
1951	class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1952	DeclSetVector &Decls;
1953	bool FoundDecl;
1954
1955	public:
1956	typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1957
1958	DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1959	Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1960	if (!Statement) return;
1961
1962	Visit(S: Statement);
1963	}
1964
1965	void VisitReturnStmt(ReturnStmt *S) {
1966	FoundDecl = true;
1967	}
1968
1969	void VisitBreakStmt(BreakStmt *S) {
1970	FoundDecl = true;
1971	}
1972
1973	void VisitGotoStmt(GotoStmt *S) {
1974	FoundDecl = true;
1975	}
1976
1977	void VisitCastExpr(CastExpr *E) {
1978	if (E->getCastKind() == CK_LValueToRValue)
1979	CheckLValueToRValueCast(E: E->getSubExpr());
1980	else
1981	Visit(S: E->getSubExpr());
1982	}
1983
1984	void CheckLValueToRValueCast(Expr *E) {
1985	E = E->IgnoreParenImpCasts();
1986
1987	if (isa<DeclRefExpr>(Val: E)) {
1988	return;
1989	}
1990
1991	if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(Val: E)) {
1992	Visit(S: CO->getCond());
1993	CheckLValueToRValueCast(E: CO->getTrueExpr());
1994	CheckLValueToRValueCast(E: CO->getFalseExpr());
1995	return;
1996	}
1997
1998	if (BinaryConditionalOperator *BCO =
1999	dyn_cast<BinaryConditionalOperator>(Val: E)) {
2000	CheckLValueToRValueCast(E: BCO->getOpaqueValue()->getSourceExpr());
2001	CheckLValueToRValueCast(E: BCO->getFalseExpr());
2002	return;
2003	}
2004
2005	Visit(S: E);
2006	}
2007
2008	void VisitDeclRefExpr(DeclRefExpr *E) {
2009	if (VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl()))
2010	if (Decls.count(key: VD))
2011	FoundDecl = true;
2012	}
2013
2014	void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
2015	// Only need to visit the semantics for POE.
2016	// SyntaticForm doesn't really use the Decal.
2017	for (auto *S : POE->semantics()) {
2018	if (auto *OVE = dyn_cast<OpaqueValueExpr>(Val: S))
2019	// Look past the OVE into the expression it binds.
2020	Visit(S: OVE->getSourceExpr());
2021	else
2022	Visit(S);
2023	}
2024	}
2025
2026	bool FoundDeclInUse() { return FoundDecl; }
2027
2028	}; // end class DeclMatcher
2029
2030	void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
2031	Expr *Third, Stmt *Body) {
2032	// Condition is empty
2033	if (!Second) return;
2034
2035	if (S.Diags.isIgnored(DiagID: diag::warn_variables_not_in_loop_body,
2036	Loc: Second->getBeginLoc()))
2037	return;
2038
2039	PartialDiagnostic PDiag = S.PDiag(DiagID: diag::warn_variables_not_in_loop_body);
2040	DeclSetVector Decls;
2041	SmallVector<SourceRange, 10> Ranges;
2042	DeclExtractor DE(S, Decls, Ranges);
2043	DE.Visit(S: Second);
2044
2045	// Don't analyze complex conditionals.
2046	if (!DE.isSimple()) return;
2047
2048	// No decls found.
2049	if (Decls.size() == 0) return;
2050
2051	// Don't warn on volatile, static, or global variables.
2052	for (auto *VD : Decls)
2053	if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
2054	return;
2055
2056	if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
2057	DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
2058	DeclMatcher(S, Decls, Body).FoundDeclInUse())
2059	return;
2060
2061	// Load decl names into diagnostic.
2062	if (Decls.size() > 4) {
2063	PDiag << 0;
2064	} else {
2065	PDiag << (unsigned)Decls.size();
2066	for (auto *VD : Decls)
2067	PDiag << VD->getDeclName();
2068	}
2069
2070	for (auto Range : Ranges)
2071	PDiag << Range;
2072
2073	S.Diag(Loc: Ranges.begin()->getBegin(), PD: PDiag);
2074	}
2075
2076	// If Statement is an incemement or decrement, return true and sets the
2077	// variables Increment and DRE.
2078	bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
2079	DeclRefExpr *&DRE) {
2080	if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: Statement))
2081	if (!Cleanups->cleanupsHaveSideEffects())
2082	Statement = Cleanups->getSubExpr();
2083
2084	if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Statement)) {
2085	switch (UO->getOpcode()) {
2086	default: return false;
2087	case UO_PostInc:
2088	case UO_PreInc:
2089	Increment = true;
2090	break;
2091	case UO_PostDec:
2092	case UO_PreDec:
2093	Increment = false;
2094	break;
2095	}
2096	DRE = dyn_cast<DeclRefExpr>(Val: UO->getSubExpr());
2097	return DRE;
2098	}
2099
2100	if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Val: Statement)) {
2101	FunctionDecl *FD = Call->getDirectCallee();
2102	if (!FD || !FD->isOverloadedOperator()) return false;
2103	switch (FD->getOverloadedOperator()) {
2104	default: return false;
2105	case OO_PlusPlus:
2106	Increment = true;
2107	break;
2108	case OO_MinusMinus:
2109	Increment = false;
2110	break;
2111	}
2112	DRE = dyn_cast<DeclRefExpr>(Val: Call->getArg(Arg: 0));
2113	return DRE;
2114	}
2115
2116	return false;
2117	}
2118
2119	// A visitor to determine if a continue or break statement is a
2120	// subexpression.
2121	class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
2122	SourceLocation BreakLoc;
2123	SourceLocation ContinueLoc;
2124	bool InSwitch = false;
2125
2126	public:
2127	BreakContinueFinder(Sema &S, const Stmt* Body) :
2128	Inherited(S.Context) {
2129	Visit(S: Body);
2130	}
2131
2132	typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
2133
2134	void VisitContinueStmt(const ContinueStmt* E) {
2135	ContinueLoc = E->getContinueLoc();
2136	}
2137
2138	void VisitBreakStmt(const BreakStmt* E) {
2139	if (!InSwitch)
2140	BreakLoc = E->getBreakLoc();
2141	}
2142
2143	void VisitSwitchStmt(const SwitchStmt* S) {
2144	if (const Stmt *Init = S->getInit())
2145	Visit(S: Init);
2146	if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
2147	Visit(S: CondVar);
2148	if (const Stmt *Cond = S->getCond())
2149	Visit(S: Cond);
2150
2151	// Don't return break statements from the body of a switch.
2152	InSwitch = true;
2153	if (const Stmt *Body = S->getBody())
2154	Visit(S: Body);
2155	InSwitch = false;
2156	}
2157
2158	void VisitForStmt(const ForStmt *S) {
2159	// Only visit the init statement of a for loop; the body
2160	// has a different break/continue scope.
2161	if (const Stmt *Init = S->getInit())
2162	Visit(S: Init);
2163	}
2164
2165	void VisitWhileStmt(const WhileStmt *) {
2166	// Do nothing; the children of a while loop have a different
2167	// break/continue scope.
2168	}
2169
2170	void VisitDoStmt(const DoStmt *) {
2171	// Do nothing; the children of a while loop have a different
2172	// break/continue scope.
2173	}
2174
2175	void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
2176	// Only visit the initialization of a for loop; the body
2177	// has a different break/continue scope.
2178	if (const Stmt *Init = S->getInit())
2179	Visit(S: Init);
2180	if (const Stmt *Range = S->getRangeStmt())
2181	Visit(S: Range);
2182	if (const Stmt *Begin = S->getBeginStmt())
2183	Visit(S: Begin);
2184	if (const Stmt *End = S->getEndStmt())
2185	Visit(S: End);
2186	}
2187
2188	void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
2189	// Only visit the initialization of a for loop; the body
2190	// has a different break/continue scope.
2191	if (const Stmt *Element = S->getElement())
2192	Visit(S: Element);
2193	if (const Stmt *Collection = S->getCollection())
2194	Visit(S: Collection);
2195	}
2196
2197	bool ContinueFound() { return ContinueLoc.isValid(); }
2198	bool BreakFound() { return BreakLoc.isValid(); }
2199	SourceLocation GetContinueLoc() { return ContinueLoc; }
2200	SourceLocation GetBreakLoc() { return BreakLoc; }
2201
2202	}; // end class BreakContinueFinder
2203
2204	// Emit a warning when a loop increment/decrement appears twice per loop
2205	// iteration. The conditions which trigger this warning are:
2206	// 1) The last statement in the loop body and the third expression in the
2207	// for loop are both increment or both decrement of the same variable
2208	// 2) No continue statements in the loop body.
2209	void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
2210	// Return when there is nothing to check.
2211	if (!Body || !Third) return;
2212
2213	// Get the last statement from the loop body.
2214	CompoundStmt *CS = dyn_cast<CompoundStmt>(Val: Body);
2215	if (!CS || CS->body_empty()) return;
2216	Stmt *LastStmt = CS->body_back();
2217	if (!LastStmt) return;
2218
2219	if (S.Diags.isIgnored(DiagID: diag::warn_redundant_loop_iteration,
2220	Loc: Third->getBeginLoc()))
2221	return;
2222
2223	bool LoopIncrement, LastIncrement;
2224	DeclRefExpr *LoopDRE, *LastDRE;
2225
2226	if (!ProcessIterationStmt(S, Statement: Third, Increment&: LoopIncrement, DRE&: LoopDRE)) return;
2227	if (!ProcessIterationStmt(S, Statement: LastStmt, Increment&: LastIncrement, DRE&: LastDRE)) return;
2228
2229	// Check that the two statements are both increments or both decrements
2230	// on the same variable.
2231	if (LoopIncrement != LastIncrement ||
2232	LoopDRE->getDecl() != LastDRE->getDecl()) return;
2233
2234	if (BreakContinueFinder(S, Body).ContinueFound()) return;
2235
2236	S.Diag(Loc: LastDRE->getLocation(), DiagID: diag::warn_redundant_loop_iteration)
2237	<< LastDRE->getDecl() << LastIncrement;
2238	S.Diag(Loc: LoopDRE->getLocation(), DiagID: diag::note_loop_iteration_here)
2239	<< LoopIncrement;
2240	}
2241
2242	} // end namespace
2243
2244
2245	void Sema::CheckBreakContinueBinding(Expr *E) {
2246	if (!E || getLangOpts().CPlusPlus)
2247	return;
2248	BreakContinueFinder BCFinder(*this, E);
2249	Scope *BreakParent = CurScope->getBreakParent();
2250	if (BCFinder.BreakFound() && BreakParent) {
2251	if (BreakParent->getFlags() & Scope::SwitchScope) {
2252	Diag(Loc: BCFinder.GetBreakLoc(), DiagID: diag::warn_break_binds_to_switch);
2253	} else {
2254	Diag(Loc: BCFinder.GetBreakLoc(), DiagID: diag::warn_loop_ctrl_binds_to_inner)
2255	<< "break";
2256	}
2257	} else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
2258	Diag(Loc: BCFinder.GetContinueLoc(), DiagID: diag::warn_loop_ctrl_binds_to_inner)
2259	<< "continue";
2260	}
2261	}
2262
2263	StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
2264	Stmt *First, ConditionResult Second,
2265	FullExprArg third, SourceLocation RParenLoc,
2266	Stmt *Body) {
2267	if (Second.isInvalid())
2268	return StmtError();
2269
2270	if (!getLangOpts().CPlusPlus) {
2271	if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(Val: First)) {
2272	// C99 6.8.5p3: The declaration part of a 'for' statement shall only
2273	// declare identifiers for objects having storage class 'auto' or
2274	// 'register'.
2275	const Decl *NonVarSeen = nullptr;
2276	bool VarDeclSeen = false;
2277	for (auto *DI : DS->decls()) {
2278	if (VarDecl *VD = dyn_cast<VarDecl>(Val: DI)) {
2279	VarDeclSeen = true;
2280	if (VD->isLocalVarDecl() && !VD->hasLocalStorage())
2281	Diag(Loc: DI->getLocation(),
2282	DiagID: getLangOpts().C23
2283	? diag::warn_c17_non_local_variable_decl_in_for
2284	: diag::ext_c23_non_local_variable_decl_in_for);
2285	} else if (!NonVarSeen) {
2286	// Keep track of the first non-variable declaration we saw so that
2287	// we can diagnose if we don't see any variable declarations. This
2288	// covers a case like declaring a typedef, function, or structure
2289	// type rather than a variable.
2290	//
2291	// Note, _Static_assert is acceptable because it does not declare an
2292	// identifier at all, so "for object having" does not apply.
2293	if (!isa<StaticAssertDecl>(Val: DI))
2294	NonVarSeen = DI;
2295	}
2296	}
2297	// Diagnose if we saw a non-variable declaration but no variable
2298	// declarations.
2299	if (NonVarSeen && !VarDeclSeen)
2300	Diag(Loc: NonVarSeen->getLocation(),
2301	DiagID: getLangOpts().C23 ? diag::warn_c17_non_variable_decl_in_for
2302	: diag::ext_c23_non_variable_decl_in_for);
2303	}
2304	}
2305
2306	CheckBreakContinueBinding(E: Second.get().second);
2307	CheckBreakContinueBinding(E: third.get());
2308
2309	if (!Second.get().first)
2310	CheckForLoopConditionalStatement(S&: *this, Second: Second.get().second, Third: third.get(),
2311	Body);
2312	CheckForRedundantIteration(S&: *this, Third: third.get(), Body);
2313
2314	if (Second.get().second &&
2315	!Diags.isIgnored(DiagID: diag::warn_comma_operator,
2316	Loc: Second.get().second->getExprLoc()))
2317	CommaVisitor(*this).Visit(S: Second.get().second);
2318
2319	Expr *Third = third.release().getAs<Expr>();
2320	if (isa<NullStmt>(Val: Body))
2321	getCurCompoundScope().setHasEmptyLoopBodies();
2322
2323	return new (Context)
2324	ForStmt(Context, First, Second.get().second, Second.get().first, Third,
2325	Body, ForLoc, LParenLoc, RParenLoc);
2326	}
2327
2328	StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
2329	// Reduce placeholder expressions here. Note that this rejects the
2330	// use of pseudo-object l-values in this position.
2331	ExprResult result = CheckPlaceholderExpr(E);
2332	if (result.isInvalid()) return StmtError();
2333	E = result.get();
2334
2335	ExprResult FullExpr = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
2336	if (FullExpr.isInvalid())
2337	return StmtError();
2338	return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2339	}
2340
2341	/// Finish building a variable declaration for a for-range statement.
2342	/// \return true if an error occurs.
2343	static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
2344	SourceLocation Loc, int DiagID) {
2345	if (Decl->getType()->isUndeducedType()) {
2346	ExprResult Res = Init;
2347	if (!Res.isUsable()) {
2348	Decl->setInvalidDecl();
2349	return true;
2350	}
2351	Init = Res.get();
2352	}
2353
2354	// Deduce the type for the iterator variable now rather than leaving it to
2355	// AddInitializerToDecl, so we can produce a more suitable diagnostic.
2356	QualType InitType;
2357	if (!isa<InitListExpr>(Val: Init) && Init->getType()->isVoidType()) {
2358	SemaRef.Diag(Loc, DiagID) << Init->getType();
2359	} else {
2360	TemplateDeductionInfo Info(Init->getExprLoc());
2361	TemplateDeductionResult Result = SemaRef.DeduceAutoType(
2362	AutoTypeLoc: Decl->getTypeSourceInfo()->getTypeLoc(), Initializer: Init, Result&: InitType, Info);
2363	if (Result != TemplateDeductionResult::Success &&
2364	Result != TemplateDeductionResult::AlreadyDiagnosed)
2365	SemaRef.Diag(Loc, DiagID) << Init->getType();
2366	}
2367
2368	if (InitType.isNull()) {
2369	Decl->setInvalidDecl();
2370	return true;
2371	}
2372	Decl->setType(InitType);
2373
2374	// In ARC, infer lifetime.
2375	// FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
2376	// we're doing the equivalent of fast iteration.
2377	if (SemaRef.getLangOpts().ObjCAutoRefCount &&
2378	SemaRef.ObjC().inferObjCARCLifetime(decl: Decl))
2379	Decl->setInvalidDecl();
2380
2381	SemaRef.AddInitializerToDecl(dcl: Decl, init: Init, /*DirectInit=*/false);
2382	SemaRef.FinalizeDeclaration(D: Decl);
2383	SemaRef.CurContext->addHiddenDecl(D: Decl);
2384	return false;
2385	}
2386
2387	namespace {
2388	// An enum to represent whether something is dealing with a call to begin()
2389	// or a call to end() in a range-based for loop.
2390	enum BeginEndFunction {
2391	BEF_begin,
2392	BEF_end
2393	};
2394
2395	/// Produce a note indicating which begin/end function was implicitly called
2396	/// by a C++11 for-range statement. This is often not obvious from the code,
2397	/// nor from the diagnostics produced when analysing the implicit expressions
2398	/// required in a for-range statement.
2399	void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2400	BeginEndFunction BEF) {
2401	CallExpr *CE = dyn_cast<CallExpr>(Val: E);
2402	if (!CE)
2403	return;
2404	FunctionDecl *D = dyn_cast<FunctionDecl>(Val: CE->getCalleeDecl());
2405	if (!D)
2406	return;
2407	SourceLocation Loc = D->getLocation();
2408
2409	std::string Description;
2410	bool IsTemplate = false;
2411	if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2412	Description = SemaRef.getTemplateArgumentBindingsText(
2413	Params: FunTmpl->getTemplateParameters(), Args: *D->getTemplateSpecializationArgs());
2414	IsTemplate = true;
2415	}
2416
2417	SemaRef.Diag(Loc, DiagID: diag::note_for_range_begin_end)
2418	<< BEF << IsTemplate << Description << E->getType();
2419	}
2420
2421	/// Build a variable declaration for a for-range statement.
2422	VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
2423	QualType Type, StringRef Name) {
2424	DeclContext *DC = SemaRef.CurContext;
2425	IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
2426	TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(T: Type, Loc);
2427	VarDecl *Decl = VarDecl::Create(C&: SemaRef.Context, DC, StartLoc: Loc, IdLoc: Loc, Id: II, T: Type,
2428	TInfo, S: SC_None);
2429	Decl->setImplicit();
2430	Decl->setCXXForRangeImplicitVar(true);
2431	return Decl;
2432	}
2433
2434	}
2435
2436	static bool ObjCEnumerationCollection(Expr *Collection) {
2437	return !Collection->isTypeDependent()
2438	&& Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2439	}
2440
2441	StmtResult Sema::ActOnCXXForRangeStmt(
2442	Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2443	Stmt *First, SourceLocation ColonLoc, Expr *Range, SourceLocation RParenLoc,
2444	BuildForRangeKind Kind,
2445	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2446	// FIXME: recover in order to allow the body to be parsed.
2447	if (!First)
2448	return StmtError();
2449
2450	if (Range && ObjCEnumerationCollection(Collection: Range)) {
2451	// FIXME: Support init-statements in Objective-C++20 ranged for statement.
2452	if (InitStmt)
2453	return Diag(Loc: InitStmt->getBeginLoc(), DiagID: diag::err_objc_for_range_init_stmt)
2454	<< InitStmt->getSourceRange();
2455	return ObjC().ActOnObjCForCollectionStmt(ForColLoc: ForLoc, First, collection: Range, RParenLoc);
2456	}
2457
2458	DeclStmt *DS = dyn_cast<DeclStmt>(Val: First);
2459	assert(DS && "first part of for range not a decl stmt");
2460
2461	if (!DS->isSingleDecl()) {
2462	Diag(Loc: DS->getBeginLoc(), DiagID: diag::err_type_defined_in_for_range);
2463	return StmtError();
2464	}
2465
2466	// This function is responsible for attaching an initializer to LoopVar. We
2467	// must call ActOnInitializerError if we fail to do so.
2468	Decl *LoopVar = DS->getSingleDecl();
2469	if (LoopVar->isInvalidDecl() || !Range ||
2470	DiagnoseUnexpandedParameterPack(E: Range, UPPC: UPPC_Expression)) {
2471	ActOnInitializerError(Dcl: LoopVar);
2472	return StmtError();
2473	}
2474
2475	// Build the coroutine state immediately and not later during template
2476	// instantiation
2477	if (!CoawaitLoc.isInvalid()) {
2478	if (!ActOnCoroutineBodyStart(S, KwLoc: CoawaitLoc, Keyword: "co_await")) {
2479	ActOnInitializerError(Dcl: LoopVar);
2480	return StmtError();
2481	}
2482	}
2483
2484	// Build auto && __range = range-init
2485	// Divide by 2, since the variables are in the inner scope (loop body).
2486	const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2487	SourceLocation RangeLoc = Range->getBeginLoc();
2488	VarDecl *RangeVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: RangeLoc,
2489	Type: Context.getAutoRRefDeductType(),
2490	Name: std::string("__range") + DepthStr);
2491	if (FinishForRangeVarDecl(SemaRef&: *this, Decl: RangeVar, Init: Range, Loc: RangeLoc,
2492	DiagID: diag::err_for_range_deduction_failure)) {
2493	ActOnInitializerError(Dcl: LoopVar);
2494	return StmtError();
2495	}
2496
2497	// Claim the type doesn't contain auto: we've already done the checking.
2498	DeclGroupPtrTy RangeGroup =
2499	BuildDeclaratorGroup(Group: MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2500	StmtResult RangeDecl = ActOnDeclStmt(dg: RangeGroup, StartLoc: RangeLoc, EndLoc: RangeLoc);
2501	if (RangeDecl.isInvalid()) {
2502	ActOnInitializerError(Dcl: LoopVar);
2503	return StmtError();
2504	}
2505
2506	StmtResult R = BuildCXXForRangeStmt(
2507	ForLoc, CoawaitLoc, InitStmt, ColonLoc, RangeDecl: RangeDecl.get(),
2508	/*BeginStmt=*/Begin: nullptr, /*EndStmt=*/End: nullptr,
2509	/*Cond=*/nullptr, /*Inc=*/nullptr, LoopVarDecl: DS, RParenLoc, Kind,
2510	LifetimeExtendTemps);
2511	if (R.isInvalid()) {
2512	ActOnInitializerError(Dcl: LoopVar);
2513	return StmtError();
2514	}
2515
2516	return R;
2517	}
2518
2519	/// Create the initialization, compare, and increment steps for
2520	/// the range-based for loop expression.
2521	/// This function does not handle array-based for loops,
2522	/// which are created in Sema::BuildCXXForRangeStmt.
2523	///
2524	/// \returns a ForRangeStatus indicating success or what kind of error occurred.
2525	/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2526	/// CandidateSet and BEF are set and some non-success value is returned on
2527	/// failure.
2528	static Sema::ForRangeStatus
2529	BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2530	QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2531	SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2532	OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2533	ExprResult *EndExpr, BeginEndFunction *BEF) {
2534	DeclarationNameInfo BeginNameInfo(
2535	&SemaRef.PP.getIdentifierTable().get(Name: "begin"), ColonLoc);
2536	DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get(Name: "end"),
2537	ColonLoc);
2538
2539	LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2540	Sema::LookupMemberName);
2541	LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2542
2543	auto BuildBegin = [&] {
2544	*BEF = BEF_begin;
2545	Sema::ForRangeStatus RangeStatus =
2546	SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: BeginNameInfo,
2547	MemberLookup&: BeginMemberLookup, CandidateSet,
2548	Range: BeginRange, CallExpr: BeginExpr);
2549
2550	if (RangeStatus != Sema::FRS_Success) {
2551	if (RangeStatus == Sema::FRS_DiagnosticIssued)
2552	SemaRef.Diag(Loc: BeginRange->getBeginLoc(), DiagID: diag::note_in_for_range)
2553	<< ColonLoc << BEF_begin << BeginRange->getType();
2554	return RangeStatus;
2555	}
2556	if (!CoawaitLoc.isInvalid()) {
2557	// FIXME: getCurScope() should not be used during template instantiation.
2558	// We should pick up the set of unqualified lookup results for operator
2559	// co_await during the initial parse.
2560	*BeginExpr = SemaRef.ActOnCoawaitExpr(S: SemaRef.getCurScope(), KwLoc: ColonLoc,
2561	E: BeginExpr->get());
2562	if (BeginExpr->isInvalid())
2563	return Sema::FRS_DiagnosticIssued;
2564	}
2565	if (FinishForRangeVarDecl(SemaRef, Decl: BeginVar, Init: BeginExpr->get(), Loc: ColonLoc,
2566	DiagID: diag::err_for_range_iter_deduction_failure)) {
2567	NoteForRangeBeginEndFunction(SemaRef, E: BeginExpr->get(), BEF: *BEF);
2568	return Sema::FRS_DiagnosticIssued;
2569	}
2570	return Sema::FRS_Success;
2571	};
2572
2573	auto BuildEnd = [&] {
2574	*BEF = BEF_end;
2575	Sema::ForRangeStatus RangeStatus =
2576	SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: EndNameInfo,
2577	MemberLookup&: EndMemberLookup, CandidateSet,
2578	Range: EndRange, CallExpr: EndExpr);
2579	if (RangeStatus != Sema::FRS_Success) {
2580	if (RangeStatus == Sema::FRS_DiagnosticIssued)
2581	SemaRef.Diag(Loc: EndRange->getBeginLoc(), DiagID: diag::note_in_for_range)
2582	<< ColonLoc << BEF_end << EndRange->getType();
2583	return RangeStatus;
2584	}
2585	if (FinishForRangeVarDecl(SemaRef, Decl: EndVar, Init: EndExpr->get(), Loc: ColonLoc,
2586	DiagID: diag::err_for_range_iter_deduction_failure)) {
2587	NoteForRangeBeginEndFunction(SemaRef, E: EndExpr->get(), BEF: *BEF);
2588	return Sema::FRS_DiagnosticIssued;
2589	}
2590	return Sema::FRS_Success;
2591	};
2592
2593	if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2594	// - if _RangeT is a class type, the unqualified-ids begin and end are
2595	// looked up in the scope of class _RangeT as if by class member access
2596	// lookup (3.4.5), and if either (or both) finds at least one
2597	// declaration, begin-expr and end-expr are __range.begin() and
2598	// __range.end(), respectively;
2599	SemaRef.LookupQualifiedName(R&: BeginMemberLookup, LookupCtx: D);
2600	if (BeginMemberLookup.isAmbiguous())
2601	return Sema::FRS_DiagnosticIssued;
2602
2603	SemaRef.LookupQualifiedName(R&: EndMemberLookup, LookupCtx: D);
2604	if (EndMemberLookup.isAmbiguous())
2605	return Sema::FRS_DiagnosticIssued;
2606
2607	if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2608	// Look up the non-member form of the member we didn't find, first.
2609	// This way we prefer a "no viable 'end'" diagnostic over a "i found
2610	// a 'begin' but ignored it because there was no member 'end'"
2611	// diagnostic.
2612	auto BuildNonmember = [&](
2613	BeginEndFunction BEFFound, LookupResult &Found,
2614	llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
2615	llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
2616	LookupResult OldFound = std::move(Found);
2617	Found.clear();
2618
2619	if (Sema::ForRangeStatus Result = BuildNotFound())
2620	return Result;
2621
2622	switch (BuildFound()) {
2623	case Sema::FRS_Success:
2624	return Sema::FRS_Success;
2625
2626	case Sema::FRS_NoViableFunction:
2627	CandidateSet->NoteCandidates(
2628	PA: PartialDiagnosticAt(BeginRange->getBeginLoc(),
2629	SemaRef.PDiag(DiagID: diag::err_for_range_invalid)
2630	<< BeginRange->getType() << BEFFound),
2631	S&: SemaRef, OCD: OCD_AllCandidates, Args: BeginRange);
2632	[[fallthrough]];
2633
2634	case Sema::FRS_DiagnosticIssued:
2635	for (NamedDecl *D : OldFound) {
2636	SemaRef.Diag(Loc: D->getLocation(),
2637	DiagID: diag::note_for_range_member_begin_end_ignored)
2638	<< BeginRange->getType() << BEFFound;
2639	}
2640	return Sema::FRS_DiagnosticIssued;
2641	}
2642	llvm_unreachable("unexpected ForRangeStatus");
2643	};
2644	if (BeginMemberLookup.empty())
2645	return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
2646	return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin, BuildEnd);
2647	}
2648	} else {
2649	// - otherwise, begin-expr and end-expr are begin(__range) and
2650	// end(__range), respectively, where begin and end are looked up with
2651	// argument-dependent lookup (3.4.2). For the purposes of this name
2652	// lookup, namespace std is an associated namespace.
2653	}
2654
2655	if (Sema::ForRangeStatus Result = BuildBegin())
2656	return Result;
2657	return BuildEnd();
2658	}
2659
2660	/// Speculatively attempt to dereference an invalid range expression.
2661	/// If the attempt fails, this function will return a valid, null StmtResult
2662	/// and emit no diagnostics.
2663	static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2664	SourceLocation ForLoc,
2665	SourceLocation CoawaitLoc,
2666	Stmt *InitStmt,
2667	Stmt *LoopVarDecl,
2668	SourceLocation ColonLoc,
2669	Expr *Range,
2670	SourceLocation RangeLoc,
2671	SourceLocation RParenLoc) {
2672	// Determine whether we can rebuild the for-range statement with a
2673	// dereferenced range expression.
2674	ExprResult AdjustedRange;
2675	{
2676	Sema::SFINAETrap Trap(SemaRef);
2677
2678	AdjustedRange = SemaRef.BuildUnaryOp(S, OpLoc: RangeLoc, Opc: UO_Deref, Input: Range);
2679	if (AdjustedRange.isInvalid())
2680	return StmtResult();
2681
2682	StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2683	S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2684	Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Check);
2685	if (SR.isInvalid())
2686	return StmtResult();
2687	}
2688
2689	// The attempt to dereference worked well enough that it could produce a valid
2690	// loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2691	// case there are any other (non-fatal) problems with it.
2692	SemaRef.Diag(Loc: RangeLoc, DiagID: diag::err_for_range_dereference)
2693	<< Range->getType() << FixItHint::CreateInsertion(InsertionLoc: RangeLoc, Code: "*");
2694	return SemaRef.ActOnCXXForRangeStmt(
2695	S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2696	Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Rebuild);
2697	}
2698
2699	StmtResult Sema::BuildCXXForRangeStmt(
2700	SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2701	SourceLocation ColonLoc, Stmt *RangeDecl, Stmt *Begin, Stmt *End,
2702	Expr *Cond, Expr *Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
2703	BuildForRangeKind Kind,
2704	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2705	// FIXME: This should not be used during template instantiation. We should
2706	// pick up the set of unqualified lookup results for the != and + operators
2707	// in the initial parse.
2708	//
2709	// Testcase (accepts-invalid):
2710	// template<typename T> void f() { for (auto x : T()) {} }
2711	// namespace N { struct X { X begin(); X end(); int operator*(); }; }
2712	// bool operator!=(N::X, N::X); void operator++(N::X);
2713	// void g() { f<N::X>(); }
2714	Scope *S = getCurScope();
2715
2716	DeclStmt *RangeDS = cast<DeclStmt>(Val: RangeDecl);
2717	VarDecl *RangeVar = cast<VarDecl>(Val: RangeDS->getSingleDecl());
2718	QualType RangeVarType = RangeVar->getType();
2719
2720	DeclStmt *LoopVarDS = cast<DeclStmt>(Val: LoopVarDecl);
2721	VarDecl *LoopVar = cast<VarDecl>(Val: LoopVarDS->getSingleDecl());
2722
2723	StmtResult BeginDeclStmt = Begin;
2724	StmtResult EndDeclStmt = End;
2725	ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2726
2727	if (RangeVarType->isDependentType()) {
2728	// The range is implicitly used as a placeholder when it is dependent.
2729	RangeVar->markUsed(C&: Context);
2730
2731	// Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2732	// them in properly when we instantiate the loop.
2733	if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2734	if (auto *DD = dyn_cast<DecompositionDecl>(Val: LoopVar))
2735	for (auto *Binding : DD->bindings()) {
2736	if (!Binding->isParameterPack())
2737	Binding->setType(Context.DependentTy);
2738	}
2739	LoopVar->setType(SubstAutoTypeDependent(TypeWithAuto: LoopVar->getType()));
2740	}
2741	} else if (!BeginDeclStmt.get()) {
2742	SourceLocation RangeLoc = RangeVar->getLocation();
2743
2744	const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2745
2746	ExprResult BeginRangeRef = BuildDeclRefExpr(D: RangeVar, Ty: RangeVarNonRefType,
2747	VK: VK_LValue, Loc: ColonLoc);
2748	if (BeginRangeRef.isInvalid())
2749	return StmtError();
2750
2751	ExprResult EndRangeRef = BuildDeclRefExpr(D: RangeVar, Ty: RangeVarNonRefType,
2752	VK: VK_LValue, Loc: ColonLoc);
2753	if (EndRangeRef.isInvalid())
2754	return StmtError();
2755
2756	QualType AutoType = Context.getAutoDeductType();
2757	Expr *Range = RangeVar->getInit();
2758	if (!Range)
2759	return StmtError();
2760	QualType RangeType = Range->getType();
2761
2762	if (RequireCompleteType(Loc: RangeLoc, T: RangeType,
2763	DiagID: diag::err_for_range_incomplete_type))
2764	return StmtError();
2765
2766	// P2718R0 - Lifetime extension in range-based for loops.
2767	if (getLangOpts().CPlusPlus23 && !LifetimeExtendTemps.empty()) {
2768	InitializedEntity Entity =
2769	InitializedEntity::InitializeVariable(Var: RangeVar);
2770	for (auto *MTE : LifetimeExtendTemps)
2771	MTE->setExtendingDecl(ExtendedBy: RangeVar, ManglingNumber: Entity.allocateManglingNumber());
2772	}
2773
2774	// Build auto __begin = begin-expr, __end = end-expr.
2775	// Divide by 2, since the variables are in the inner scope (loop body).
2776	const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2777	VarDecl *BeginVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: ColonLoc, Type: AutoType,
2778	Name: std::string("__begin") + DepthStr);
2779	VarDecl *EndVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: ColonLoc, Type: AutoType,
2780	Name: std::string("__end") + DepthStr);
2781
2782	// Build begin-expr and end-expr and attach to __begin and __end variables.
2783	ExprResult BeginExpr, EndExpr;
2784	if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2785	// - if _RangeT is an array type, begin-expr and end-expr are __range and
2786	// __range + __bound, respectively, where __bound is the array bound. If
2787	// _RangeT is an array of unknown size or an array of incomplete type,
2788	// the program is ill-formed;
2789
2790	// begin-expr is __range.
2791	BeginExpr = BeginRangeRef;
2792	if (!CoawaitLoc.isInvalid()) {
2793	BeginExpr = ActOnCoawaitExpr(S, KwLoc: ColonLoc, E: BeginExpr.get());
2794	if (BeginExpr.isInvalid())
2795	return StmtError();
2796	}
2797	if (FinishForRangeVarDecl(SemaRef&: *this, Decl: BeginVar, Init: BeginRangeRef.get(), Loc: ColonLoc,
2798	DiagID: diag::err_for_range_iter_deduction_failure)) {
2799	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2800	return StmtError();
2801	}
2802
2803	// Find the array bound.
2804	ExprResult BoundExpr;
2805	if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Val: UnqAT))
2806	BoundExpr = IntegerLiteral::Create(
2807	C: Context, V: CAT->getSize(), type: Context.getPointerDiffType(), l: RangeLoc);
2808	else if (const VariableArrayType *VAT =
2809	dyn_cast<VariableArrayType>(Val: UnqAT)) {
2810	// For a variably modified type we can't just use the expression within
2811	// the array bounds, since we don't want that to be re-evaluated here.
2812	// Rather, we need to determine what it was when the array was first
2813	// created - so we resort to using sizeof(vla)/sizeof(element).
2814	// For e.g.
2815	// void f(int b) {
2816	// int vla[b];
2817	// b = -1; <-- This should not affect the num of iterations below
2818	// for (int &c : vla) { .. }
2819	// }
2820
2821	// FIXME: This results in codegen generating IR that recalculates the
2822	// run-time number of elements (as opposed to just using the IR Value
2823	// that corresponds to the run-time value of each bound that was
2824	// generated when the array was created.) If this proves too embarrassing
2825	// even for unoptimized IR, consider passing a magic-value/cookie to
2826	// codegen that then knows to simply use that initial llvm::Value (that
2827	// corresponds to the bound at time of array creation) within
2828	// getelementptr. But be prepared to pay the price of increasing a
2829	// customized form of coupling between the two components - which could
2830	// be hard to maintain as the codebase evolves.
2831
2832	ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2833	OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2834	/*IsType=*/true,
2835	TyOrEx: CreateParsedType(T: VAT->desugar(), TInfo: Context.getTrivialTypeSourceInfo(
2836	T: VAT->desugar(), Loc: RangeLoc))
2837	.getAsOpaquePtr(),
2838	ArgRange: EndVar->getSourceRange());
2839	if (SizeOfVLAExprR.isInvalid())
2840	return StmtError();
2841
2842	ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2843	OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2844	/*IsType=*/true,
2845	TyOrEx: CreateParsedType(T: VAT->desugar(),
2846	TInfo: Context.getTrivialTypeSourceInfo(
2847	T: VAT->getElementType(), Loc: RangeLoc))
2848	.getAsOpaquePtr(),
2849	ArgRange: EndVar->getSourceRange());
2850	if (SizeOfEachElementExprR.isInvalid())
2851	return StmtError();
2852
2853	BoundExpr =
2854	ActOnBinOp(S, TokLoc: EndVar->getLocation(), Kind: tok::slash,
2855	LHSExpr: SizeOfVLAExprR.get(), RHSExpr: SizeOfEachElementExprR.get());
2856	if (BoundExpr.isInvalid())
2857	return StmtError();
2858
2859	} else {
2860	// Can't be a DependentSizedArrayType or an IncompleteArrayType since
2861	// UnqAT is not incomplete and Range is not type-dependent.
2862	llvm_unreachable("Unexpected array type in for-range");
2863	}
2864
2865	// end-expr is __range + __bound.
2866	EndExpr = ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::plus, LHSExpr: EndRangeRef.get(),
2867	RHSExpr: BoundExpr.get());
2868	if (EndExpr.isInvalid())
2869	return StmtError();
2870	if (FinishForRangeVarDecl(SemaRef&: *this, Decl: EndVar, Init: EndExpr.get(), Loc: ColonLoc,
2871	DiagID: diag::err_for_range_iter_deduction_failure)) {
2872	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
2873	return StmtError();
2874	}
2875	} else {
2876	OverloadCandidateSet CandidateSet(RangeLoc,
2877	OverloadCandidateSet::CSK_Normal);
2878	BeginEndFunction BEFFailure;
2879	ForRangeStatus RangeStatus = BuildNonArrayForRange(
2880	SemaRef&: *this, BeginRange: BeginRangeRef.get(), EndRange: EndRangeRef.get(), RangeType, BeginVar,
2881	EndVar, ColonLoc, CoawaitLoc, CandidateSet: &CandidateSet, BeginExpr: &BeginExpr, EndExpr: &EndExpr,
2882	BEF: &BEFFailure);
2883
2884	if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2885	BEFFailure == BEF_begin) {
2886	// If the range is being built from an array parameter, emit a
2887	// a diagnostic that it is being treated as a pointer.
2888	if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Range)) {
2889	if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Val: DRE->getDecl())) {
2890	QualType ArrayTy = PVD->getOriginalType();
2891	QualType PointerTy = PVD->getType();
2892	if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2893	Diag(Loc: Range->getBeginLoc(), DiagID: diag::err_range_on_array_parameter)
2894	<< RangeLoc << PVD << ArrayTy << PointerTy;
2895	Diag(Loc: PVD->getLocation(), DiagID: diag::note_declared_at);
2896	return StmtError();
2897	}
2898	}
2899	}
2900
2901	// If building the range failed, try dereferencing the range expression
2902	// unless a diagnostic was issued or the end function is problematic.
2903	StmtResult SR = RebuildForRangeWithDereference(SemaRef&: *this, S, ForLoc,
2904	CoawaitLoc, InitStmt,
2905	LoopVarDecl, ColonLoc,
2906	Range, RangeLoc,
2907	RParenLoc);
2908	if (SR.isInvalid() || SR.isUsable())
2909	return SR;
2910	}
2911
2912	// Otherwise, emit diagnostics if we haven't already.
2913	if (RangeStatus == FRS_NoViableFunction) {
2914	Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2915	CandidateSet.NoteCandidates(
2916	PA: PartialDiagnosticAt(Range->getBeginLoc(),
2917	PDiag(DiagID: diag::err_for_range_invalid)
2918	<< RangeLoc << Range->getType()
2919	<< BEFFailure),
2920	S&: *this, OCD: OCD_AllCandidates, Args: Range);
2921	}
2922	// Return an error if no fix was discovered.
2923	if (RangeStatus != FRS_Success)
2924	return StmtError();
2925	}
2926
2927	assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
2928	"invalid range expression in for loop");
2929
2930	// C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
2931	// C++1z removes this restriction.
2932	QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
2933	if (!Context.hasSameType(T1: BeginType, T2: EndType)) {
2934	Diag(Loc: RangeLoc, DiagID: getLangOpts().CPlusPlus17
2935	? diag::warn_for_range_begin_end_types_differ
2936	: diag::ext_for_range_begin_end_types_differ)
2937	<< BeginType << EndType;
2938	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2939	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
2940	}
2941
2942	BeginDeclStmt =
2943	ActOnDeclStmt(dg: ConvertDeclToDeclGroup(Ptr: BeginVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
2944	EndDeclStmt =
2945	ActOnDeclStmt(dg: ConvertDeclToDeclGroup(Ptr: EndVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
2946
2947	const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2948	ExprResult BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
2949	VK: VK_LValue, Loc: ColonLoc);
2950	if (BeginRef.isInvalid())
2951	return StmtError();
2952
2953	ExprResult EndRef = BuildDeclRefExpr(D: EndVar, Ty: EndType.getNonReferenceType(),
2954	VK: VK_LValue, Loc: ColonLoc);
2955	if (EndRef.isInvalid())
2956	return StmtError();
2957
2958	// Build and check __begin != __end expression.
2959	NotEqExpr = ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::exclaimequal,
2960	LHSExpr: BeginRef.get(), RHSExpr: EndRef.get());
2961	if (!NotEqExpr.isInvalid())
2962	NotEqExpr = CheckBooleanCondition(Loc: ColonLoc, E: NotEqExpr.get());
2963	if (!NotEqExpr.isInvalid())
2964	NotEqExpr =
2965	ActOnFinishFullExpr(Expr: NotEqExpr.get(), /*DiscardedValue*/ false);
2966	if (NotEqExpr.isInvalid()) {
2967	Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
2968	<< RangeLoc << 0 << BeginRangeRef.get()->getType();
2969	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2970	if (!Context.hasSameType(T1: BeginType, T2: EndType))
2971	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
2972	return StmtError();
2973	}
2974
2975	// Build and check ++__begin expression.
2976	BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
2977	VK: VK_LValue, Loc: ColonLoc);
2978	if (BeginRef.isInvalid())
2979	return StmtError();
2980
2981	IncrExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::plusplus, Input: BeginRef.get());
2982	if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
2983	// FIXME: getCurScope() should not be used during template instantiation.
2984	// We should pick up the set of unqualified lookup results for operator
2985	// co_await during the initial parse.
2986	IncrExpr = ActOnCoawaitExpr(S, KwLoc: CoawaitLoc, E: IncrExpr.get());
2987	if (!IncrExpr.isInvalid())
2988	IncrExpr = ActOnFinishFullExpr(Expr: IncrExpr.get(), /*DiscardedValue*/ false);
2989	if (IncrExpr.isInvalid()) {
2990	Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
2991	<< RangeLoc << 2 << BeginRangeRef.get()->getType() ;
2992	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2993	return StmtError();
2994	}
2995
2996	// Build and check *__begin expression.
2997	BeginRef = BuildDeclRefExpr(D: BeginVar, Ty: BeginRefNonRefType,
2998	VK: VK_LValue, Loc: ColonLoc);
2999	if (BeginRef.isInvalid())
3000	return StmtError();
3001
3002	ExprResult DerefExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::star, Input: BeginRef.get());
3003	if (DerefExpr.isInvalid()) {
3004	Diag(Loc: RangeLoc, DiagID: diag::note_for_range_invalid_iterator)
3005	<< RangeLoc << 1 << BeginRangeRef.get()->getType();
3006	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3007	return StmtError();
3008	}
3009
3010	// Attach *__begin as initializer for VD. Don't touch it if we're just
3011	// trying to determine whether this would be a valid range.
3012	if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
3013	AddInitializerToDecl(dcl: LoopVar, init: DerefExpr.get(), /*DirectInit=*/false);
3014	if (LoopVar->isInvalidDecl() ||
3015	(LoopVar->getInit() && LoopVar->getInit()->containsErrors()))
3016	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3017	}
3018	}
3019
3020	// Don't bother to actually allocate the result if we're just trying to
3021	// determine whether it would be valid.
3022	if (Kind == BFRK_Check)
3023	return StmtResult();
3024
3025	// In OpenMP loop region loop control variable must be private. Perform
3026	// analysis of first part (if any).
3027	if (getLangOpts().OpenMP >= 50 && BeginDeclStmt.isUsable())
3028	OpenMP().ActOnOpenMPLoopInitialization(ForLoc, Init: BeginDeclStmt.get());
3029
3030	return new (Context) CXXForRangeStmt(
3031	InitStmt, RangeDS, cast_or_null<DeclStmt>(Val: BeginDeclStmt.get()),
3032	cast_or_null<DeclStmt>(Val: EndDeclStmt.get()), NotEqExpr.get(),
3033	IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
3034	ColonLoc, RParenLoc);
3035	}
3036
3037	// Warn when the loop variable is a const reference that creates a copy.
3038	// Suggest using the non-reference type for copies. If a copy can be prevented
3039	// suggest the const reference type that would do so.
3040	// For instance, given "for (const &Foo : Range)", suggest
3041	// "for (const Foo : Range)" to denote a copy is made for the loop. If
3042	// possible, also suggest "for (const &Bar : Range)" if this type prevents
3043	// the copy altogether.
3044	static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
3045	const VarDecl *VD,
3046	QualType RangeInitType) {
3047	const Expr *InitExpr = VD->getInit();
3048	if (!InitExpr)
3049	return;
3050
3051	QualType VariableType = VD->getType();
3052
3053	if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: InitExpr))
3054	if (!Cleanups->cleanupsHaveSideEffects())
3055	InitExpr = Cleanups->getSubExpr();
3056
3057	const MaterializeTemporaryExpr *MTE =
3058	dyn_cast<MaterializeTemporaryExpr>(Val: InitExpr);
3059
3060	// No copy made.
3061	if (!MTE)
3062	return;
3063
3064	const Expr *E = MTE->getSubExpr()->IgnoreImpCasts();
3065
3066	// Searching for either UnaryOperator for dereference of a pointer or
3067	// CXXOperatorCallExpr for handling iterators.
3068	while (!isa<CXXOperatorCallExpr>(Val: E) && !isa<UnaryOperator>(Val: E)) {
3069	if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Val: E)) {
3070	E = CCE->getArg(Arg: 0);
3071	} else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(Val: E)) {
3072	const MemberExpr *ME = cast<MemberExpr>(Val: Call->getCallee());
3073	E = ME->getBase();
3074	} else {
3075	const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(Val: E);
3076	E = MTE->getSubExpr();
3077	}
3078	E = E->IgnoreImpCasts();
3079	}
3080
3081	QualType ReferenceReturnType;
3082	if (isa<UnaryOperator>(Val: E)) {
3083	ReferenceReturnType = SemaRef.Context.getLValueReferenceType(T: E->getType());
3084	} else {
3085	const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(Val: E);
3086	const FunctionDecl *FD = Call->getDirectCallee();
3087	QualType ReturnType = FD->getReturnType();
3088	if (ReturnType->isReferenceType())
3089	ReferenceReturnType = ReturnType;
3090	}
3091
3092	if (!ReferenceReturnType.isNull()) {
3093	// Loop variable creates a temporary. Suggest either to go with
3094	// non-reference loop variable to indicate a copy is made, or
3095	// the correct type to bind a const reference.
3096	SemaRef.Diag(Loc: VD->getLocation(),
3097	DiagID: diag::warn_for_range_const_ref_binds_temp_built_from_ref)
3098	<< VD << VariableType << ReferenceReturnType;
3099	QualType NonReferenceType = VariableType.getNonReferenceType();
3100	NonReferenceType.removeLocalConst();
3101	QualType NewReferenceType =
3102	SemaRef.Context.getLValueReferenceType(T: E->getType().withConst());
3103	SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_type_or_non_reference)
3104	<< NonReferenceType << NewReferenceType << VD->getSourceRange()
3105	<< FixItHint::CreateRemoval(RemoveRange: VD->getTypeSpecEndLoc());
3106	} else if (!VariableType->isRValueReferenceType()) {
3107	// The range always returns a copy, so a temporary is always created.
3108	// Suggest removing the reference from the loop variable.
3109	// If the type is a rvalue reference do not warn since that changes the
3110	// semantic of the code.
3111	SemaRef.Diag(Loc: VD->getLocation(), DiagID: diag::warn_for_range_ref_binds_ret_temp)
3112	<< VD << RangeInitType;
3113	QualType NonReferenceType = VariableType.getNonReferenceType();
3114	NonReferenceType.removeLocalConst();
3115	SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_non_reference_type)
3116	<< NonReferenceType << VD->getSourceRange()
3117	<< FixItHint::CreateRemoval(RemoveRange: VD->getTypeSpecEndLoc());
3118	}
3119	}
3120
3121	/// Determines whether the @p VariableType's declaration is a record with the
3122	/// clang::trivial_abi attribute.
3123	static bool hasTrivialABIAttr(QualType VariableType) {
3124	if (CXXRecordDecl *RD = VariableType->getAsCXXRecordDecl())
3125	return RD->hasAttr<TrivialABIAttr>();
3126
3127	return false;
3128	}
3129
3130	// Warns when the loop variable can be changed to a reference type to
3131	// prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
3132	// "for (const Foo &x : Range)" if this form does not make a copy.
3133	static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
3134	const VarDecl *VD) {
3135	const Expr *InitExpr = VD->getInit();
3136	if (!InitExpr)
3137	return;
3138
3139	QualType VariableType = VD->getType();
3140
3141	if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: InitExpr)) {
3142	if (!CE->getConstructor()->isCopyConstructor())
3143	return;
3144	} else if (const CastExpr *CE = dyn_cast<CastExpr>(Val: InitExpr)) {
3145	if (CE->getCastKind() != CK_LValueToRValue)
3146	return;
3147	} else {
3148	return;
3149	}
3150
3151	// Small trivially copyable types are cheap to copy. Do not emit the
3152	// diagnostic for these instances. 64 bytes is a common size of a cache line.
3153	// (The function `getTypeSize` returns the size in bits.)
3154	ASTContext &Ctx = SemaRef.Context;
3155	if (Ctx.getTypeSize(T: VariableType) <= 64 * 8 &&
3156	(VariableType.isTriviallyCopyConstructibleType(Context: Ctx) ||
3157	hasTrivialABIAttr(VariableType)))
3158	return;
3159
3160	// Suggest changing from a const variable to a const reference variable
3161	// if doing so will prevent a copy.
3162	SemaRef.Diag(Loc: VD->getLocation(), DiagID: diag::warn_for_range_copy)
3163	<< VD << VariableType;
3164	SemaRef.Diag(Loc: VD->getBeginLoc(), DiagID: diag::note_use_reference_type)
3165	<< SemaRef.Context.getLValueReferenceType(T: VariableType)
3166	<< VD->getSourceRange()
3167	<< FixItHint::CreateInsertion(InsertionLoc: VD->getLocation(), Code: "&");
3168	}
3169
3170	/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
3171	/// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
3172	/// using "const foo x" to show that a copy is made
3173	/// 2) for (const bar &x : foos) where bar is a temporary initialized by bar.
3174	/// Suggest either "const bar x" to keep the copying or "const foo& x" to
3175	/// prevent the copy.
3176	/// 3) for (const foo x : foos) where x is constructed from a reference foo.
3177	/// Suggest "const foo &x" to prevent the copy.
3178	static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
3179	const CXXForRangeStmt *ForStmt) {
3180	if (SemaRef.inTemplateInstantiation())
3181	return;
3182
3183	SourceLocation Loc = ForStmt->getBeginLoc();
3184	if (SemaRef.Diags.isIgnored(
3185	DiagID: diag::warn_for_range_const_ref_binds_temp_built_from_ref, Loc) &&
3186	SemaRef.Diags.isIgnored(DiagID: diag::warn_for_range_ref_binds_ret_temp, Loc) &&
3187	SemaRef.Diags.isIgnored(DiagID: diag::warn_for_range_copy, Loc)) {
3188	return;
3189	}
3190
3191	const VarDecl *VD = ForStmt->getLoopVariable();
3192	if (!VD)
3193	return;
3194
3195	QualType VariableType = VD->getType();
3196
3197	if (VariableType->isIncompleteType())
3198	return;
3199
3200	const Expr *InitExpr = VD->getInit();
3201	if (!InitExpr)
3202	return;
3203
3204	if (InitExpr->getExprLoc().isMacroID())
3205	return;
3206
3207	if (VariableType->isReferenceType()) {
3208	DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
3209	RangeInitType: ForStmt->getRangeInit()->getType());
3210	} else if (VariableType.isConstQualified()) {
3211	DiagnoseForRangeConstVariableCopies(SemaRef, VD);
3212	}
3213	}
3214
3215	StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
3216	if (!S || !B)
3217	return StmtError();
3218
3219	if (isa<ObjCForCollectionStmt>(Val: S))
3220	return ObjC().FinishObjCForCollectionStmt(ForCollection: S, Body: B);
3221
3222	CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(Val: S);
3223	ForStmt->setBody(B);
3224
3225	DiagnoseEmptyStmtBody(StmtLoc: ForStmt->getRParenLoc(), Body: B,
3226	DiagID: diag::warn_empty_range_based_for_body);
3227
3228	DiagnoseForRangeVariableCopies(SemaRef&: *this, ForStmt);
3229
3230	return S;
3231	}
3232
3233	StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
3234	SourceLocation LabelLoc,
3235	LabelDecl *TheDecl) {
3236	setFunctionHasBranchIntoScope();
3237
3238	// If this goto is in a compute construct scope, we need to make sure we check
3239	// gotos in/out.
3240	if (getCurScope()->isInOpenACCComputeConstructScope())
3241	setFunctionHasBranchProtectedScope();
3242
3243	TheDecl->markUsed(C&: Context);
3244	return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
3245	}
3246
3247	StmtResult
3248	Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
3249	Expr *E) {
3250	// Convert operand to void*
3251	if (!E->isTypeDependent()) {
3252	QualType ETy = E->getType();
3253	QualType DestTy = Context.getPointerType(T: Context.VoidTy.withConst());
3254	ExprResult ExprRes = E;
3255	AssignConvertType ConvTy =
3256	CheckSingleAssignmentConstraints(LHSType: DestTy, RHS&: ExprRes);
3257	if (ExprRes.isInvalid())
3258	return StmtError();
3259	E = ExprRes.get();
3260	if (DiagnoseAssignmentResult(ConvTy, Loc: StarLoc, DstType: DestTy, SrcType: ETy, SrcExpr: E,
3261	Action: AssignmentAction::Passing))
3262	return StmtError();
3263	}
3264
3265	ExprResult ExprRes = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
3266	if (ExprRes.isInvalid())
3267	return StmtError();
3268	E = ExprRes.get();
3269
3270	setFunctionHasIndirectGoto();
3271
3272	// If this goto is in a compute construct scope, we need to make sure we
3273	// check gotos in/out.
3274	if (getCurScope()->isInOpenACCComputeConstructScope())
3275	setFunctionHasBranchProtectedScope();
3276
3277	return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
3278	}
3279
3280	static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
3281	const Scope &DestScope) {
3282	if (!S.CurrentSEHFinally.empty() &&
3283	DestScope.Contains(rhs: *S.CurrentSEHFinally.back())) {
3284	S.Diag(Loc, DiagID: diag::warn_jump_out_of_seh_finally);
3285	}
3286	}
3287
3288	StmtResult
3289	Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
3290	Scope *S = CurScope->getContinueParent();
3291	if (!S) {
3292	// C99 6.8.6.2p1: A break shall appear only in or as a loop body.
3293	return StmtError(Diag(Loc: ContinueLoc, DiagID: diag::err_continue_not_in_loop));
3294	}
3295	if (S->isConditionVarScope()) {
3296	// We cannot 'continue;' from within a statement expression in the
3297	// initializer of a condition variable because we would jump past the
3298	// initialization of that variable.
3299	return StmtError(Diag(Loc: ContinueLoc, DiagID: diag::err_continue_from_cond_var_init));
3300	}
3301
3302	// A 'continue' that would normally have execution continue on a block outside
3303	// of a compute construct counts as 'branching out of' the compute construct,
3304	// so diagnose here.
3305	if (S->isOpenACCComputeConstructScope())
3306	return StmtError(
3307	Diag(Loc: ContinueLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3308	<< /*branch*/ 0 << /*out of */ 0);
3309
3310	CheckJumpOutOfSEHFinally(S&: *this, Loc: ContinueLoc, DestScope: *S);
3311
3312	return new (Context) ContinueStmt(ContinueLoc);
3313	}
3314
3315	StmtResult
3316	Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
3317	Scope *S = CurScope->getBreakParent();
3318	if (!S) {
3319	// C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
3320	return StmtError(Diag(Loc: BreakLoc, DiagID: diag::err_break_not_in_loop_or_switch));
3321	}
3322	if (S->isOpenMPLoopScope())
3323	return StmtError(Diag(Loc: BreakLoc, DiagID: diag::err_omp_loop_cannot_use_stmt)
3324	<< "break");
3325
3326	// OpenACC doesn't allow 'break'ing from a compute construct, so diagnose if
3327	// we are trying to do so. This can come in 2 flavors: 1-the break'able thing
3328	// (besides the compute construct) 'contains' the compute construct, at which
3329	// point the 'break' scope will be the compute construct. Else it could be a
3330	// loop of some sort that has a direct parent of the compute construct.
3331	// However, a 'break' in a 'switch' marked as a compute construct doesn't
3332	// count as 'branch out of' the compute construct.
3333	if (S->isOpenACCComputeConstructScope() ||
3334	(S->isLoopScope() && S->getParent() &&
3335	S->getParent()->isOpenACCComputeConstructScope()))
3336	return StmtError(
3337	Diag(Loc: BreakLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3338	<< /*branch*/ 0 << /*out of */ 0);
3339
3340	CheckJumpOutOfSEHFinally(S&: *this, Loc: BreakLoc, DestScope: *S);
3341
3342	return new (Context) BreakStmt(BreakLoc);
3343	}
3344
3345	Sema::NamedReturnInfo Sema::getNamedReturnInfo(Expr *&E,
3346	SimplerImplicitMoveMode Mode) {
3347	if (!E)
3348	return NamedReturnInfo();
3349	// - in a return statement in a function [where] ...
3350	// ... the expression is the name of a non-volatile automatic object ...
3351	const auto *DR = dyn_cast<DeclRefExpr>(Val: E->IgnoreParens());
3352	if (!DR || DR->refersToEnclosingVariableOrCapture())
3353	return NamedReturnInfo();
3354	const auto *VD = dyn_cast<VarDecl>(Val: DR->getDecl());
3355	if (!VD)
3356	return NamedReturnInfo();
3357	if (VD->getInit() && VD->getInit()->containsErrors())
3358	return NamedReturnInfo();
3359	NamedReturnInfo Res = getNamedReturnInfo(VD);
3360	if (Res.Candidate && !E->isXValue() &&
3361	(Mode == SimplerImplicitMoveMode::ForceOn ||
3362	(Mode != SimplerImplicitMoveMode::ForceOff &&
3363	getLangOpts().CPlusPlus23))) {
3364	E = ImplicitCastExpr::Create(Context, T: VD->getType().getNonReferenceType(),
3365	Kind: CK_NoOp, Operand: E, BasePath: nullptr, Cat: VK_XValue,
3366	FPO: FPOptionsOverride());
3367	}
3368	return Res;
3369	}
3370
3371	Sema::NamedReturnInfo Sema::getNamedReturnInfo(const VarDecl *VD) {
3372	NamedReturnInfo Info{.Candidate: VD, .S: NamedReturnInfo::MoveEligibleAndCopyElidable};
3373
3374	// C++20 [class.copy.elision]p3:
3375	// - in a return statement in a function with ...
3376	// (other than a function ... parameter)
3377	if (VD->getKind() == Decl::ParmVar)
3378	Info.S = NamedReturnInfo::MoveEligible;
3379	else if (VD->getKind() != Decl::Var)
3380	return NamedReturnInfo();
3381
3382	// (other than ... a catch-clause parameter)
3383	if (VD->isExceptionVariable())
3384	Info.S = NamedReturnInfo::MoveEligible;
3385
3386	// ...automatic...
3387	if (!VD->hasLocalStorage())
3388	return NamedReturnInfo();
3389
3390	// We don't want to implicitly move out of a __block variable during a return
3391	// because we cannot assume the variable will no longer be used.
3392	if (VD->hasAttr<BlocksAttr>())
3393	return NamedReturnInfo();
3394
3395	QualType VDType = VD->getType();
3396	if (VDType->isObjectType()) {
3397	// C++17 [class.copy.elision]p3:
3398	// ...non-volatile automatic object...
3399	if (VDType.isVolatileQualified())
3400	return NamedReturnInfo();
3401	} else if (VDType->isRValueReferenceType()) {
3402	// C++20 [class.copy.elision]p3:
3403	// ...either a non-volatile object or an rvalue reference to a non-volatile
3404	// object type...
3405	QualType VDReferencedType = VDType.getNonReferenceType();
3406	if (VDReferencedType.isVolatileQualified() ||
3407	!VDReferencedType->isObjectType())
3408	return NamedReturnInfo();
3409	Info.S = NamedReturnInfo::MoveEligible;
3410	} else {
3411	return NamedReturnInfo();
3412	}
3413
3414	// Variables with higher required alignment than their type's ABI
3415	// alignment cannot use NRVO.
3416	if (!VD->hasDependentAlignment() && !VDType->isIncompleteType() &&
3417	Context.getDeclAlign(D: VD) > Context.getTypeAlignInChars(T: VDType))
3418	Info.S = NamedReturnInfo::MoveEligible;
3419
3420	return Info;
3421	}
3422
3423	const VarDecl *Sema::getCopyElisionCandidate(NamedReturnInfo &Info,
3424	QualType ReturnType) {
3425	if (!Info.Candidate)
3426	return nullptr;
3427
3428	auto invalidNRVO = [&] {
3429	Info = NamedReturnInfo();
3430	return nullptr;
3431	};
3432
3433	// If we got a non-deduced auto ReturnType, we are in a dependent context and
3434	// there is no point in allowing copy elision since we won't have it deduced
3435	// by the point the VardDecl is instantiated, which is the last chance we have
3436	// of deciding if the candidate is really copy elidable.
3437	if ((ReturnType->getTypeClass() == Type::TypeClass::Auto &&
3438	ReturnType->isCanonicalUnqualified()) ||
3439	ReturnType->isSpecificBuiltinType(K: BuiltinType::Dependent))
3440	return invalidNRVO();
3441
3442	if (!ReturnType->isDependentType()) {
3443	// - in a return statement in a function with ...
3444	// ... a class return type ...
3445	if (!ReturnType->isRecordType())
3446	return invalidNRVO();
3447
3448	QualType VDType = Info.Candidate->getType();
3449	// ... the same cv-unqualified type as the function return type ...
3450	// When considering moving this expression out, allow dissimilar types.
3451	if (!VDType->isDependentType() &&
3452	!Context.hasSameUnqualifiedType(T1: ReturnType, T2: VDType))
3453	Info.S = NamedReturnInfo::MoveEligible;
3454	}
3455	return Info.isCopyElidable() ? Info.Candidate : nullptr;
3456	}
3457
3458	/// Verify that the initialization sequence that was picked for the
3459	/// first overload resolution is permissible under C++98.
3460	///
3461	/// Reject (possibly converting) constructors not taking an rvalue reference,
3462	/// or user conversion operators which are not ref-qualified.
3463	static bool
3464	VerifyInitializationSequenceCXX98(const Sema &S,
3465	const InitializationSequence &Seq) {
3466	const auto *Step = llvm::find_if(Range: Seq.steps(), P: [](const auto &Step) {
3467	return Step.Kind == InitializationSequence::SK_ConstructorInitialization ||
3468	Step.Kind == InitializationSequence::SK_UserConversion;
3469	});
3470	if (Step != Seq.step_end()) {
3471	const auto *FD = Step->Function.Function;
3472	if (isa<CXXConstructorDecl>(Val: FD)
3473	? !FD->getParamDecl(i: 0)->getType()->isRValueReferenceType()
3474	: cast<CXXMethodDecl>(Val: FD)->getRefQualifier() == RQ_None)
3475	return false;
3476	}
3477	return true;
3478	}
3479
3480	ExprResult Sema::PerformMoveOrCopyInitialization(
3481	const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
3482	bool SupressSimplerImplicitMoves) {
3483	if (getLangOpts().CPlusPlus &&
3484	(!getLangOpts().CPlusPlus23 || SupressSimplerImplicitMoves) &&
3485	NRInfo.isMoveEligible()) {
3486	ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
3487	CK_NoOp, Value, VK_XValue, FPOptionsOverride());
3488	Expr *InitExpr = &AsRvalue;
3489	auto Kind = InitializationKind::CreateCopy(InitLoc: Value->getBeginLoc(),
3490	EqualLoc: Value->getBeginLoc());
3491	InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3492	auto Res = Seq.getFailedOverloadResult();
3493	if ((Res == OR_Success || Res == OR_Deleted) &&
3494	(getLangOpts().CPlusPlus11 ||
3495	VerifyInitializationSequenceCXX98(S: *this, Seq))) {
3496	// Promote "AsRvalue" to the heap, since we now need this
3497	// expression node to persist.
3498	Value =
3499	ImplicitCastExpr::Create(Context, T: Value->getType(), Kind: CK_NoOp, Operand: Value,
3500	BasePath: nullptr, Cat: VK_XValue, FPO: FPOptionsOverride());
3501	// Complete type-checking the initialization of the return type
3502	// using the constructor we found.
3503	return Seq.Perform(S&: *this, Entity, Kind, Args: Value);
3504	}
3505	}
3506	// Either we didn't meet the criteria for treating an lvalue as an rvalue,
3507	// above, or overload resolution failed. Either way, we need to try
3508	// (again) now with the return value expression as written.
3509	return PerformCopyInitialization(Entity, EqualLoc: SourceLocation(), Init: Value);
3510	}
3511
3512	/// Determine whether the declared return type of the specified function
3513	/// contains 'auto'.
3514	static bool hasDeducedReturnType(FunctionDecl *FD) {
3515	const FunctionProtoType *FPT =
3516	FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
3517	return FPT->getReturnType()->isUndeducedType();
3518	}
3519
3520	StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
3521	Expr *RetValExp,
3522	NamedReturnInfo &NRInfo,
3523	bool SupressSimplerImplicitMoves) {
3524	// If this is the first return we've seen, infer the return type.
3525	// [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
3526	CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(Val: getCurFunction());
3527	QualType FnRetType = CurCap->ReturnType;
3528	LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(Val: CurCap);
3529	if (CurLambda && CurLambda->CallOperator->getType().isNull())
3530	return StmtError();
3531	bool HasDeducedReturnType =
3532	CurLambda && hasDeducedReturnType(FD: CurLambda->CallOperator);
3533
3534	if (ExprEvalContexts.back().isDiscardedStatementContext() &&
3535	(HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
3536	if (RetValExp) {
3537	ExprResult ER =
3538	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3539	if (ER.isInvalid())
3540	return StmtError();
3541	RetValExp = ER.get();
3542	}
3543	return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
3544	/* NRVOCandidate=*/nullptr);
3545	}
3546
3547	if (HasDeducedReturnType) {
3548	FunctionDecl *FD = CurLambda->CallOperator;
3549	// If we've already decided this lambda is invalid, e.g. because
3550	// we saw a `return` whose expression had an error, don't keep
3551	// trying to deduce its return type.
3552	if (FD->isInvalidDecl())
3553	return StmtError();
3554	// In C++1y, the return type may involve 'auto'.
3555	// FIXME: Blocks might have a return type of 'auto' explicitly specified.
3556	if (CurCap->ReturnType.isNull())
3557	CurCap->ReturnType = FD->getReturnType();
3558
3559	AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3560	assert(AT && "lost auto type from lambda return type");
3561	if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
3562	FD->setInvalidDecl();
3563	// FIXME: preserve the ill-formed return expression.
3564	return StmtError();
3565	}
3566	CurCap->ReturnType = FnRetType = FD->getReturnType();
3567	} else if (CurCap->HasImplicitReturnType) {
3568	// For blocks/lambdas with implicit return types, we check each return
3569	// statement individually, and deduce the common return type when the block
3570	// or lambda is completed.
3571	// FIXME: Fold this into the 'auto' codepath above.
3572	if (RetValExp && !isa<InitListExpr>(Val: RetValExp)) {
3573	ExprResult Result = DefaultFunctionArrayLvalueConversion(E: RetValExp);
3574	if (Result.isInvalid())
3575	return StmtError();
3576	RetValExp = Result.get();
3577
3578	// DR1048: even prior to C++14, we should use the 'auto' deduction rules
3579	// when deducing a return type for a lambda-expression (or by extension
3580	// for a block). These rules differ from the stated C++11 rules only in
3581	// that they remove top-level cv-qualifiers.
3582	if (!CurContext->isDependentContext())
3583	FnRetType = RetValExp->getType().getUnqualifiedType();
3584	else
3585	FnRetType = CurCap->ReturnType = Context.DependentTy;
3586	} else {
3587	if (RetValExp) {
3588	// C++11 [expr.lambda.prim]p4 bans inferring the result from an
3589	// initializer list, because it is not an expression (even
3590	// though we represent it as one). We still deduce 'void'.
3591	Diag(Loc: ReturnLoc, DiagID: diag::err_lambda_return_init_list)
3592	<< RetValExp->getSourceRange();
3593	}
3594
3595	FnRetType = Context.VoidTy;
3596	}
3597
3598	// Although we'll properly infer the type of the block once it's completed,
3599	// make sure we provide a return type now for better error recovery.
3600	if (CurCap->ReturnType.isNull())
3601	CurCap->ReturnType = FnRetType;
3602	}
3603	const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
3604
3605	if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap)) {
3606	if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
3607	Diag(Loc: ReturnLoc, DiagID: diag::err_noreturn_has_return_expr)
3608	<< diag::FalloffFunctionKind::Block;
3609	return StmtError();
3610	}
3611	} else if (auto *CurRegion = dyn_cast<CapturedRegionScopeInfo>(Val: CurCap)) {
3612	Diag(Loc: ReturnLoc, DiagID: diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3613	return StmtError();
3614	} else {
3615	assert(CurLambda && "unknown kind of captured scope");
3616	if (CurLambda->CallOperator->getType()
3617	->castAs<FunctionType>()
3618	->getNoReturnAttr()) {
3619	Diag(Loc: ReturnLoc, DiagID: diag::err_noreturn_has_return_expr)
3620	<< diag::FalloffFunctionKind::Lambda;
3621	return StmtError();
3622	}
3623	}
3624
3625	// Otherwise, verify that this result type matches the previous one. We are
3626	// pickier with blocks than for normal functions because we don't have GCC
3627	// compatibility to worry about here.
3628	if (FnRetType->isDependentType()) {
3629	// Delay processing for now. TODO: there are lots of dependent
3630	// types we can conclusively prove aren't void.
3631	} else if (FnRetType->isVoidType()) {
3632	if (RetValExp && !isa<InitListExpr>(Val: RetValExp) &&
3633	!(getLangOpts().CPlusPlus &&
3634	(RetValExp->isTypeDependent() ||
3635	RetValExp->getType()->isVoidType()))) {
3636	if (!getLangOpts().CPlusPlus &&
3637	RetValExp->getType()->isVoidType())
3638	Diag(Loc: ReturnLoc, DiagID: diag::ext_return_has_void_expr) << "literal" << 2;
3639	else {
3640	Diag(Loc: ReturnLoc, DiagID: diag::err_return_block_has_expr);
3641	RetValExp = nullptr;
3642	}
3643	}
3644	} else if (!RetValExp) {
3645	return StmtError(Diag(Loc: ReturnLoc, DiagID: diag::err_block_return_missing_expr));
3646	} else if (!RetValExp->isTypeDependent()) {
3647	// we have a non-void block with an expression, continue checking
3648
3649	// C99 6.8.6.4p3(136): The return statement is not an assignment. The
3650	// overlap restriction of subclause 6.5.16.1 does not apply to the case of
3651	// function return.
3652
3653	// In C++ the return statement is handled via a copy initialization.
3654	// the C version of which boils down to CheckSingleAssignmentConstraints.
3655	InitializedEntity Entity =
3656	InitializedEntity::InitializeResult(ReturnLoc, Type: FnRetType);
3657	ExprResult Res = PerformMoveOrCopyInitialization(
3658	Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
3659	if (Res.isInvalid()) {
3660	// FIXME: Cleanup temporaries here, anyway?
3661	return StmtError();
3662	}
3663	RetValExp = Res.get();
3664	CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc);
3665	}
3666
3667	if (RetValExp) {
3668	ExprResult ER =
3669	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3670	if (ER.isInvalid())
3671	return StmtError();
3672	RetValExp = ER.get();
3673	}
3674	auto *Result =
3675	ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
3676
3677	// If we need to check for the named return value optimization,
3678	// or if we need to infer the return type,
3679	// save the return statement in our scope for later processing.
3680	if (CurCap->HasImplicitReturnType || NRVOCandidate)
3681	FunctionScopes.back()->Returns.push_back(Elt: Result);
3682
3683	if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3684	FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3685
3686	if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap);
3687	CurBlock && CurCap->HasImplicitReturnType && RetValExp &&
3688	RetValExp->containsErrors())
3689	CurBlock->TheDecl->setInvalidDecl();
3690
3691	return Result;
3692	}
3693
3694	namespace {
3695	/// Marks all typedefs in all local classes in a type referenced.
3696	///
3697	/// In a function like
3698	/// auto f() {
3699	/// struct S { typedef int a; };
3700	/// return S();
3701	/// }
3702	///
3703	/// the local type escapes and could be referenced in some TUs but not in
3704	/// others. Pretend that all local typedefs are always referenced, to not warn
3705	/// on this. This isn't necessary if f has internal linkage, or the typedef
3706	/// is private.
3707	class LocalTypedefNameReferencer : public DynamicRecursiveASTVisitor {
3708	public:
3709	LocalTypedefNameReferencer(Sema &S) : S(S) {}
3710	bool VisitRecordType(RecordType *RT) override;
3711
3712	private:
3713	Sema &S;
3714	};
3715	bool LocalTypedefNameReferencer::VisitRecordType(RecordType *RT) {
3716	auto *R = dyn_cast<CXXRecordDecl>(Val: RT->getDecl());
3717	if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3718	R->isDependentType())
3719	return true;
3720	for (auto *TmpD : R->decls())
3721	if (auto *T = dyn_cast<TypedefNameDecl>(Val: TmpD))
3722	if (T->getAccess() != AS_private || R->hasFriends())
3723	S.MarkAnyDeclReferenced(Loc: T->getLocation(), D: T, /*OdrUse=*/MightBeOdrUse: false);
3724	return true;
3725	}
3726	}
3727
3728	TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3729	return FD->getTypeSourceInfo()
3730	->getTypeLoc()
3731	.getAsAdjusted<FunctionProtoTypeLoc>()
3732	.getReturnLoc();
3733	}
3734
3735	bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3736	SourceLocation ReturnLoc,
3737	Expr *RetExpr, const AutoType *AT) {
3738	// If this is the conversion function for a lambda, we choose to deduce its
3739	// type from the corresponding call operator, not from the synthesized return
3740	// statement within it. See Sema::DeduceReturnType.
3741	if (isLambdaConversionOperator(D: FD))
3742	return false;
3743
3744	if (isa_and_nonnull<InitListExpr>(Val: RetExpr)) {
3745	// If the deduction is for a return statement and the initializer is
3746	// a braced-init-list, the program is ill-formed.
3747	Diag(Loc: RetExpr->getExprLoc(),
3748	DiagID: getCurLambda() ? diag::err_lambda_return_init_list
3749	: diag::err_auto_fn_return_init_list)
3750	<< RetExpr->getSourceRange();
3751	return true;
3752	}
3753
3754	if (FD->isDependentContext()) {
3755	// C++1y [dcl.spec.auto]p12:
3756	// Return type deduction [...] occurs when the definition is
3757	// instantiated even if the function body contains a return
3758	// statement with a non-type-dependent operand.
3759	assert(AT->isDeduced() && "should have deduced to dependent type");
3760	return false;
3761	}
3762
3763	TypeLoc OrigResultType = getReturnTypeLoc(FD);
3764	// In the case of a return with no operand, the initializer is considered
3765	// to be void().
3766	CXXScalarValueInitExpr VoidVal(Context.VoidTy, nullptr, SourceLocation());
3767	if (!RetExpr) {
3768	// For a function with a deduced result type to return with omitted
3769	// expression, the result type as written must be 'auto' or
3770	// 'decltype(auto)', possibly cv-qualified or constrained, but not
3771	// ref-qualified.
3772	if (!OrigResultType.getType()->getAs<AutoType>()) {
3773	Diag(Loc: ReturnLoc, DiagID: diag::err_auto_fn_return_void_but_not_auto)
3774	<< OrigResultType.getType();
3775	return true;
3776	}
3777	RetExpr = &VoidVal;
3778	}
3779
3780	QualType Deduced = AT->getDeducedType();
3781	{
3782	// Otherwise, [...] deduce a value for U using the rules of template
3783	// argument deduction.
3784	auto RetExprLoc = RetExpr->getExprLoc();
3785	TemplateDeductionInfo Info(RetExprLoc);
3786	SourceLocation TemplateSpecLoc;
3787	if (RetExpr->getType() == Context.OverloadTy) {
3788	auto FindResult = OverloadExpr::find(E: RetExpr);
3789	if (FindResult.Expression)
3790	TemplateSpecLoc = FindResult.Expression->getNameLoc();
3791	}
3792	TemplateSpecCandidateSet FailedTSC(TemplateSpecLoc);
3793	TemplateDeductionResult Res = DeduceAutoType(
3794	AutoTypeLoc: OrigResultType, Initializer: RetExpr, Result&: Deduced, Info, /*DependentDeduction=*/false,
3795	/*IgnoreConstraints=*/false, FailedTSC: &FailedTSC);
3796	if (Res != TemplateDeductionResult::Success && FD->isInvalidDecl())
3797	return true;
3798	switch (Res) {
3799	case TemplateDeductionResult::Success:
3800	break;
3801	case TemplateDeductionResult::AlreadyDiagnosed:
3802	return true;
3803	case TemplateDeductionResult::Inconsistent: {
3804	// If a function with a declared return type that contains a placeholder
3805	// type has multiple return statements, the return type is deduced for
3806	// each return statement. [...] if the type deduced is not the same in
3807	// each deduction, the program is ill-formed.
3808	const LambdaScopeInfo *LambdaSI = getCurLambda();
3809	if (LambdaSI && LambdaSI->HasImplicitReturnType)
3810	Diag(Loc: ReturnLoc, DiagID: diag::err_typecheck_missing_return_type_incompatible)
3811	<< Info.SecondArg << Info.FirstArg << true /*IsLambda*/;
3812	else
3813	Diag(Loc: ReturnLoc, DiagID: diag::err_auto_fn_different_deductions)
3814	<< (AT->isDecltypeAuto() ? 1 : 0) << Info.SecondArg
3815	<< Info.FirstArg;
3816	return true;
3817	}
3818	default:
3819	Diag(Loc: RetExpr->getExprLoc(), DiagID: diag::err_auto_fn_deduction_failure)
3820	<< OrigResultType.getType() << RetExpr->getType();
3821	FailedTSC.NoteCandidates(S&: *this, Loc: RetExprLoc);
3822	return true;
3823	}
3824	}
3825
3826	// If a local type is part of the returned type, mark its fields as
3827	// referenced.
3828	LocalTypedefNameReferencer(*this).TraverseType(T: RetExpr->getType());
3829
3830	// CUDA: Kernel function must have 'void' return type.
3831	if (getLangOpts().CUDA && FD->hasAttr<CUDAGlobalAttr>() &&
3832	!Deduced->isVoidType()) {
3833	Diag(Loc: FD->getLocation(), DiagID: diag::err_kern_type_not_void_return)
3834	<< FD->getType() << FD->getSourceRange();
3835	return true;
3836	}
3837
3838	if (!FD->isInvalidDecl() && AT->getDeducedType() != Deduced)
3839	// Update all declarations of the function to have the deduced return type.
3840	Context.adjustDeducedFunctionResultType(FD, ResultType: Deduced);
3841
3842	return false;
3843	}
3844
3845	StmtResult
3846	Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3847	Scope *CurScope) {
3848	ExprResult RetVal = RetValExp;
3849	if (RetVal.isInvalid())
3850	return StmtError();
3851
3852	if (getCurScope()->isInOpenACCComputeConstructScope())
3853	return StmtError(
3854	Diag(Loc: ReturnLoc, DiagID: diag::err_acc_branch_in_out_compute_construct)
3855	<< /*return*/ 1 << /*out of */ 0);
3856
3857	// using plain return in a coroutine is not allowed.
3858	FunctionScopeInfo *FSI = getCurFunction();
3859	if (FSI->FirstReturnLoc.isInvalid() && FSI->isCoroutine()) {
3860	assert(FSI->FirstCoroutineStmtLoc.isValid() &&
3861	"first coroutine location not set");
3862	Diag(Loc: ReturnLoc, DiagID: diag::err_return_in_coroutine);
3863	Diag(Loc: FSI->FirstCoroutineStmtLoc, DiagID: diag::note_declared_coroutine_here)
3864	<< FSI->getFirstCoroutineStmtKeyword();
3865	}
3866
3867	CheckInvalidBuiltinCountedByRef(E: RetVal.get(),
3868	K: BuiltinCountedByRefKind::ReturnArg);
3869
3870	StmtResult R =
3871	BuildReturnStmt(ReturnLoc, RetValExp: RetVal.get(), /*AllowRecovery=*/true);
3872	if (R.isInvalid() || ExprEvalContexts.back().isDiscardedStatementContext())
3873	return R;
3874
3875	VarDecl *VD =
3876	const_cast<VarDecl *>(cast<ReturnStmt>(Val: R.get())->getNRVOCandidate());
3877
3878	CurScope->updateNRVOCandidate(VD);
3879
3880	CheckJumpOutOfSEHFinally(S&: *this, Loc: ReturnLoc, DestScope: *CurScope->getFnParent());
3881
3882	return R;
3883	}
3884
3885	static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
3886	const Expr *E) {
3887	if (!E || !S.getLangOpts().CPlusPlus23 || !S.getLangOpts().MSVCCompat)
3888	return false;
3889	const Decl *D = E->getReferencedDeclOfCallee();
3890	if (!D || !S.SourceMgr.isInSystemHeader(Loc: D->getLocation()))
3891	return false;
3892	for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
3893	if (DC->isStdNamespace())
3894	return true;
3895	}
3896	return false;
3897	}
3898
3899	StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3900	bool AllowRecovery) {
3901	// Check for unexpanded parameter packs.
3902	if (RetValExp && DiagnoseUnexpandedParameterPack(E: RetValExp))
3903	return StmtError();
3904
3905	// HACK: We suppress simpler implicit move here in msvc compatibility mode
3906	// just as a temporary work around, as the MSVC STL has issues with
3907	// this change.
3908	bool SupressSimplerImplicitMoves =
3909	CheckSimplerImplicitMovesMSVCWorkaround(S: *this, E: RetValExp);
3910	NamedReturnInfo NRInfo = getNamedReturnInfo(
3911	E&: RetValExp, Mode: SupressSimplerImplicitMoves ? SimplerImplicitMoveMode::ForceOff
3912	: SimplerImplicitMoveMode::Normal);
3913
3914	if (isa<CapturingScopeInfo>(Val: getCurFunction()))
3915	return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
3916	SupressSimplerImplicitMoves);
3917
3918	QualType FnRetType;
3919	QualType RelatedRetType;
3920	const AttrVec *Attrs = nullptr;
3921	bool isObjCMethod = false;
3922
3923	if (const FunctionDecl *FD = getCurFunctionDecl()) {
3924	FnRetType = FD->getReturnType();
3925	if (FD->hasAttrs())
3926	Attrs = &FD->getAttrs();
3927	if (FD->isNoReturn() && !getCurFunction()->isCoroutine())
3928	Diag(Loc: ReturnLoc, DiagID: diag::warn_noreturn_function_has_return_expr) << FD;
3929	if (FD->isMain() && RetValExp)
3930	if (isa<CXXBoolLiteralExpr>(Val: RetValExp))
3931	Diag(Loc: ReturnLoc, DiagID: diag::warn_main_returns_bool_literal)
3932	<< RetValExp->getSourceRange();
3933	if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
3934	if (const auto *RT = dyn_cast<RecordType>(Val: FnRetType.getCanonicalType())) {
3935	if (RT->getDecl()->isOrContainsUnion())
3936	Diag(Loc: RetValExp->getBeginLoc(), DiagID: diag::warn_cmse_nonsecure_union) << 1;
3937	}
3938	}
3939	} else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3940	FnRetType = MD->getReturnType();
3941	isObjCMethod = true;
3942	if (MD->hasAttrs())
3943	Attrs = &MD->getAttrs();
3944	if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3945	// In the implementation of a method with a related return type, the
3946	// type used to type-check the validity of return statements within the
3947	// method body is a pointer to the type of the class being implemented.
3948	RelatedRetType = Context.getObjCInterfaceType(Decl: MD->getClassInterface());
3949	RelatedRetType = Context.getObjCObjectPointerType(OIT: RelatedRetType);
3950	}
3951	} else // If we don't have a function/method context, bail.
3952	return StmtError();
3953
3954	if (RetValExp) {
3955	const auto *ATy = dyn_cast<ArrayType>(Val: RetValExp->getType());
3956	if (ATy && ATy->getElementType().isWebAssemblyReferenceType()) {
3957	Diag(Loc: ReturnLoc, DiagID: diag::err_wasm_table_art) << 1;
3958	return StmtError();
3959	}
3960	}
3961
3962	// C++1z: discarded return statements are not considered when deducing a
3963	// return type.
3964	if (ExprEvalContexts.back().isDiscardedStatementContext() &&
3965	FnRetType->getContainedAutoType()) {
3966	if (RetValExp) {
3967	ExprResult ER =
3968	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3969	if (ER.isInvalid())
3970	return StmtError();
3971	RetValExp = ER.get();
3972	}
3973	return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
3974	/* NRVOCandidate=*/nullptr);
3975	}
3976
3977	// FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3978	// deduction.
3979	if (getLangOpts().CPlusPlus14) {
3980	if (AutoType *AT = FnRetType->getContainedAutoType()) {
3981	FunctionDecl *FD = cast<FunctionDecl>(Val: CurContext);
3982	// If we've already decided this function is invalid, e.g. because
3983	// we saw a `return` whose expression had an error, don't keep
3984	// trying to deduce its return type.
3985	// (Some return values may be needlessly wrapped in RecoveryExpr).
3986	if (FD->isInvalidDecl() ||
3987	DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
3988	FD->setInvalidDecl();
3989	if (!AllowRecovery)
3990	return StmtError();
3991	// The deduction failure is diagnosed and marked, try to recover.
3992	if (RetValExp) {
3993	// Wrap return value with a recovery expression of the previous type.
3994	// If no deduction yet, use DependentTy.
3995	auto Recovery = CreateRecoveryExpr(
3996	Begin: RetValExp->getBeginLoc(), End: RetValExp->getEndLoc(), SubExprs: RetValExp,
3997	T: AT->isDeduced() ? FnRetType : QualType());
3998	if (Recovery.isInvalid())
3999	return StmtError();
4000	RetValExp = Recovery.get();
4001	} else {
4002	// Nothing to do: a ReturnStmt with no value is fine recovery.
4003	}
4004	} else {
4005	FnRetType = FD->getReturnType();
4006	}
4007	}
4008	}
4009	const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
4010
4011	bool HasDependentReturnType = FnRetType->isDependentType();
4012
4013	ReturnStmt *Result = nullptr;
4014	if (FnRetType->isVoidType()) {
4015	if (RetValExp) {
4016	if (auto *ILE = dyn_cast<InitListExpr>(Val: RetValExp)) {
4017	// We simply never allow init lists as the return value of void
4018	// functions. This is compatible because this was never allowed before,
4019	// so there's no legacy code to deal with.
4020	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4021	int FunctionKind = 0;
4022	if (isa<ObjCMethodDecl>(Val: CurDecl))
4023	FunctionKind = 1;
4024	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4025	FunctionKind = 2;
4026	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4027	FunctionKind = 3;
4028
4029	Diag(Loc: ReturnLoc, DiagID: diag::err_return_init_list)
4030	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4031
4032	// Preserve the initializers in the AST.
4033	RetValExp = AllowRecovery
4034	? CreateRecoveryExpr(Begin: ILE->getLBraceLoc(),
4035	End: ILE->getRBraceLoc(), SubExprs: ILE->inits())
4036	.get()
4037	: nullptr;
4038	} else if (!RetValExp->isTypeDependent()) {
4039	// C99 6.8.6.4p1 (ext_ since GCC warns)
4040	unsigned D = diag::ext_return_has_expr;
4041	if (RetValExp->getType()->isVoidType()) {
4042	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4043	if (isa<CXXConstructorDecl>(Val: CurDecl) ||
4044	isa<CXXDestructorDecl>(Val: CurDecl))
4045	D = diag::err_ctor_dtor_returns_void;
4046	else
4047	D = diag::ext_return_has_void_expr;
4048	}
4049	else {
4050	ExprResult Result = RetValExp;
4051	Result = IgnoredValueConversions(E: Result.get());
4052	if (Result.isInvalid())
4053	return StmtError();
4054	RetValExp = Result.get();
4055	RetValExp = ImpCastExprToType(E: RetValExp,
4056	Type: Context.VoidTy, CK: CK_ToVoid).get();
4057	}
4058	// return of void in constructor/destructor is illegal in C++.
4059	if (D == diag::err_ctor_dtor_returns_void) {
4060	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4061	Diag(Loc: ReturnLoc, DiagID: D) << CurDecl << isa<CXXDestructorDecl>(Val: CurDecl)
4062	<< RetValExp->getSourceRange();
4063	}
4064	// return (some void expression); is legal in C++ and C2y.
4065	else if (D != diag::ext_return_has_void_expr ||
4066	(!getLangOpts().CPlusPlus && !getLangOpts().C2y)) {
4067	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4068
4069	int FunctionKind = 0;
4070	if (isa<ObjCMethodDecl>(Val: CurDecl))
4071	FunctionKind = 1;
4072	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4073	FunctionKind = 2;
4074	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4075	FunctionKind = 3;
4076
4077	Diag(Loc: ReturnLoc, DiagID: D)
4078	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4079	}
4080	}
4081
4082	if (RetValExp) {
4083	ExprResult ER =
4084	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4085	if (ER.isInvalid())
4086	return StmtError();
4087	RetValExp = ER.get();
4088	}
4089	}
4090
4091	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4092	/* NRVOCandidate=*/nullptr);
4093	} else if (!RetValExp && !HasDependentReturnType) {
4094	FunctionDecl *FD = getCurFunctionDecl();
4095
4096	if ((FD && FD->isInvalidDecl()) || FnRetType->containsErrors()) {
4097	// The intended return type might have been "void", so don't warn.
4098	} else if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
4099	// C++11 [stmt.return]p2
4100	Diag(Loc: ReturnLoc, DiagID: diag::err_constexpr_return_missing_expr)
4101	<< FD << FD->isConsteval();
4102	FD->setInvalidDecl();
4103	} else {
4104	// C99 6.8.6.4p1 (ext_ since GCC warns)
4105	// C90 6.6.6.4p4
4106	unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
4107	: diag::warn_return_missing_expr;
4108	// Note that at this point one of getCurFunctionDecl() or
4109	// getCurMethodDecl() must be non-null (see above).
4110	assert((getCurFunctionDecl() || getCurMethodDecl()) &&
4111	"Not in a FunctionDecl or ObjCMethodDecl?");
4112	bool IsMethod = FD == nullptr;
4113	const NamedDecl *ND =
4114	IsMethod ? cast<NamedDecl>(Val: getCurMethodDecl()) : cast<NamedDecl>(Val: FD);
4115	Diag(Loc: ReturnLoc, DiagID) << ND << IsMethod;
4116	}
4117
4118	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, /* RetExpr=*/E: nullptr,
4119	/* NRVOCandidate=*/nullptr);
4120	} else {
4121	assert(RetValExp || HasDependentReturnType);
4122	QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
4123
4124	// C99 6.8.6.4p3(136): The return statement is not an assignment. The
4125	// overlap restriction of subclause 6.5.16.1 does not apply to the case of
4126	// function return.
4127
4128	// In C++ the return statement is handled via a copy initialization,
4129	// the C version of which boils down to CheckSingleAssignmentConstraints.
4130	if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
4131	// we have a non-void function with an expression, continue checking
4132	InitializedEntity Entity =
4133	InitializedEntity::InitializeResult(ReturnLoc, Type: RetType);
4134	ExprResult Res = PerformMoveOrCopyInitialization(
4135	Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
4136	if (Res.isInvalid() && AllowRecovery)
4137	Res = CreateRecoveryExpr(Begin: RetValExp->getBeginLoc(),
4138	End: RetValExp->getEndLoc(), SubExprs: RetValExp, T: RetType);
4139	if (Res.isInvalid()) {
4140	// FIXME: Clean up temporaries here anyway?
4141	return StmtError();
4142	}
4143	RetValExp = Res.getAs<Expr>();
4144
4145	// If we have a related result type, we need to implicitly
4146	// convert back to the formal result type. We can't pretend to
4147	// initialize the result again --- we might end double-retaining
4148	// --- so instead we initialize a notional temporary.
4149	if (!RelatedRetType.isNull()) {
4150	Entity = InitializedEntity::InitializeRelatedResult(MD: getCurMethodDecl(),
4151	Type: FnRetType);
4152	Res = PerformCopyInitialization(Entity, EqualLoc: ReturnLoc, Init: RetValExp);
4153	if (Res.isInvalid()) {
4154	// FIXME: Clean up temporaries here anyway?
4155	return StmtError();
4156	}
4157	RetValExp = Res.getAs<Expr>();
4158	}
4159
4160	CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc, isObjCMethod, Attrs,
4161	FD: getCurFunctionDecl());
4162	}
4163
4164	if (RetValExp) {
4165	ExprResult ER =
4166	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4167	if (ER.isInvalid())
4168	return StmtError();
4169	RetValExp = ER.get();
4170	}
4171	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
4172	}
4173
4174	// If we need to check for the named return value optimization, save the
4175	// return statement in our scope for later processing.
4176	if (Result->getNRVOCandidate())
4177	FunctionScopes.back()->Returns.push_back(Elt: Result);
4178
4179	if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
4180	FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
4181
4182	return Result;
4183	}
4184
4185	StmtResult
4186	Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
4187	Stmt *HandlerBlock) {
4188	// There's nothing to test that ActOnExceptionDecl didn't already test.
4189	return new (Context)
4190	CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(Val: ExDecl), HandlerBlock);
4191	}
4192
4193	namespace {
4194	class CatchHandlerType {
4195	QualType QT;
4196	LLVM_PREFERRED_TYPE(bool)
4197	unsigned IsPointer : 1;
4198
4199	// This is a special constructor to be used only with DenseMapInfo's
4200	// getEmptyKey() and getTombstoneKey() functions.
4201	friend struct llvm::DenseMapInfo<CatchHandlerType>;
4202	enum Unique { ForDenseMap };
4203	CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
4204
4205	public:
4206	/// Used when creating a CatchHandlerType from a handler type; will determine
4207	/// whether the type is a pointer or reference and will strip off the top
4208	/// level pointer and cv-qualifiers.
4209	CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
4210	if (QT->isPointerType())
4211	IsPointer = true;
4212
4213	QT = QT.getUnqualifiedType();
4214	if (IsPointer || QT->isReferenceType())
4215	QT = QT->getPointeeType();
4216	}
4217
4218	/// Used when creating a CatchHandlerType from a base class type; pretends the
4219	/// type passed in had the pointer qualifier, does not need to get an
4220	/// unqualified type.
4221	CatchHandlerType(QualType QT, bool IsPointer)
4222	: QT(QT), IsPointer(IsPointer) {}
4223
4224	QualType underlying() const { return QT; }
4225	bool isPointer() const { return IsPointer; }
4226
4227	friend bool operator==(const CatchHandlerType &LHS,
4228	const CatchHandlerType &RHS) {
4229	// If the pointer qualification does not match, we can return early.
4230	if (LHS.IsPointer != RHS.IsPointer)
4231	return false;
4232	// Otherwise, check the underlying type without cv-qualifiers.
4233	return LHS.QT == RHS.QT;
4234	}
4235	};
4236	} // namespace
4237
4238	namespace llvm {
4239	template <> struct DenseMapInfo<CatchHandlerType> {
4240	static CatchHandlerType getEmptyKey() {
4241	return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
4242	CatchHandlerType::ForDenseMap);
4243	}
4244
4245	static CatchHandlerType getTombstoneKey() {
4246	return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
4247	CatchHandlerType::ForDenseMap);
4248	}
4249
4250	static unsigned getHashValue(const CatchHandlerType &Base) {
4251	return DenseMapInfo<QualType>::getHashValue(Val: Base.underlying());
4252	}
4253
4254	static bool isEqual(const CatchHandlerType &LHS,
4255	const CatchHandlerType &RHS) {
4256	return LHS == RHS;
4257	}
4258	};
4259	}
4260
4261	namespace {
4262	class CatchTypePublicBases {
4263	const llvm::DenseMap<QualType, CXXCatchStmt *> &TypesToCheck;
4264
4265	CXXCatchStmt *FoundHandler;
4266	QualType FoundHandlerType;
4267	QualType TestAgainstType;
4268
4269	public:
4270	CatchTypePublicBases(const llvm::DenseMap<QualType, CXXCatchStmt *> &T,
4271	QualType QT)
4272	: TypesToCheck(T), FoundHandler(nullptr), TestAgainstType(QT) {}
4273
4274	CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
4275	QualType getFoundHandlerType() const { return FoundHandlerType; }
4276
4277	bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
4278	if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
4279	QualType Check = S->getType().getCanonicalType();
4280	const auto &M = TypesToCheck;
4281	auto I = M.find(Val: Check);
4282	if (I != M.end()) {
4283	// We're pretty sure we found what we need to find. However, we still
4284	// need to make sure that we properly compare for pointers and
4285	// references, to handle cases like:
4286	//
4287	// } catch (Base *b) {
4288	// } catch (Derived &d) {
4289	// }
4290	//
4291	// where there is a qualification mismatch that disqualifies this
4292	// handler as a potential problem.
4293	if (I->second->getCaughtType()->isPointerType() ==
4294	TestAgainstType->isPointerType()) {
4295	FoundHandler = I->second;
4296	FoundHandlerType = Check;
4297	return true;
4298	}
4299	}
4300	}
4301	return false;
4302	}
4303	};
4304	}
4305
4306	StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
4307	ArrayRef<Stmt *> Handlers) {
4308	const llvm::Triple &T = Context.getTargetInfo().getTriple();
4309	const bool IsOpenMPGPUTarget =
4310	getLangOpts().OpenMPIsTargetDevice && (T.isNVPTX() || T.isAMDGCN());
4311
4312	DiagnoseExceptionUse(Loc: TryLoc, /* IsTry= */ true);
4313
4314	// In OpenMP target regions, we assume that catch is never reached on GPU
4315	// targets.
4316	if (IsOpenMPGPUTarget)
4317	targetDiag(Loc: TryLoc, DiagID: diag::warn_try_not_valid_on_target) << T.str();
4318
4319	// Exceptions aren't allowed in CUDA device code.
4320	if (getLangOpts().CUDA)
4321	CUDA().DiagIfDeviceCode(Loc: TryLoc, DiagID: diag::err_cuda_device_exceptions)
4322	<< "try" << CUDA().CurrentTarget();
4323
4324	if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
4325	Diag(Loc: TryLoc, DiagID: diag::err_omp_simd_region_cannot_use_stmt) << "try";
4326
4327	sema::FunctionScopeInfo *FSI = getCurFunction();
4328
4329	// C++ try is incompatible with SEH __try.
4330	if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
4331	Diag(Loc: TryLoc, DiagID: diag::err_mixing_cxx_try_seh_try) << 0;
4332	Diag(Loc: FSI->FirstSEHTryLoc, DiagID: diag::note_conflicting_try_here) << "'__try'";
4333	}
4334
4335	const unsigned NumHandlers = Handlers.size();
4336	assert(!Handlers.empty() &&
4337	"The parser shouldn't call this if there are no handlers.");
4338
4339	llvm::DenseMap<QualType, CXXCatchStmt *> HandledBaseTypes;
4340	llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
4341	for (unsigned i = 0; i < NumHandlers; ++i) {
4342	CXXCatchStmt *H = cast<CXXCatchStmt>(Val: Handlers[i]);
4343
4344	// Diagnose when the handler is a catch-all handler, but it isn't the last
4345	// handler for the try block. [except.handle]p5. Also, skip exception
4346	// declarations that are invalid, since we can't usefully report on them.
4347	if (!H->getExceptionDecl()) {
4348	if (i < NumHandlers - 1)
4349	return StmtError(Diag(Loc: H->getBeginLoc(), DiagID: diag::err_early_catch_all));
4350	continue;
4351	} else if (H->getExceptionDecl()->isInvalidDecl())
4352	continue;
4353
4354	// Walk the type hierarchy to diagnose when this type has already been
4355	// handled (duplication), or cannot be handled (derivation inversion). We
4356	// ignore top-level cv-qualifiers, per [except.handle]p3
4357	CatchHandlerType HandlerCHT = H->getCaughtType().getCanonicalType();
4358
4359	// We can ignore whether the type is a reference or a pointer; we need the
4360	// underlying declaration type in order to get at the underlying record
4361	// decl, if there is one.
4362	QualType Underlying = HandlerCHT.underlying();
4363	if (auto *RD = Underlying->getAsCXXRecordDecl()) {
4364	if (!RD->hasDefinition())
4365	continue;
4366	// Check that none of the public, unambiguous base classes are in the
4367	// map ([except.handle]p1). Give the base classes the same pointer
4368	// qualification as the original type we are basing off of. This allows
4369	// comparison against the handler type using the same top-level pointer
4370	// as the original type.
4371	CXXBasePaths Paths;
4372	Paths.setOrigin(RD);
4373	CatchTypePublicBases CTPB(HandledBaseTypes,
4374	H->getCaughtType().getCanonicalType());
4375	if (RD->lookupInBases(BaseMatches: CTPB, Paths)) {
4376	const CXXCatchStmt *Problem = CTPB.getFoundHandler();
4377	if (!Paths.isAmbiguous(
4378	BaseType: CanQualType::CreateUnsafe(Other: CTPB.getFoundHandlerType()))) {
4379	Diag(Loc: H->getExceptionDecl()->getTypeSpecStartLoc(),
4380	DiagID: diag::warn_exception_caught_by_earlier_handler)
4381	<< H->getCaughtType();
4382	Diag(Loc: Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4383	DiagID: diag::note_previous_exception_handler)
4384	<< Problem->getCaughtType();
4385	}
4386	}
4387	// Strip the qualifiers here because we're going to be comparing this
4388	// type to the base type specifiers of a class, which are ignored in a
4389	// base specifier per [class.derived.general]p2.
4390	HandledBaseTypes[Underlying.getUnqualifiedType()] = H;
4391	}
4392
4393	// Add the type the list of ones we have handled; diagnose if we've already
4394	// handled it.
4395	auto R = HandledTypes.insert(
4396	KV: std::make_pair(x: H->getCaughtType().getCanonicalType(), y&: H));
4397	if (!R.second) {
4398	const CXXCatchStmt *Problem = R.first->second;
4399	Diag(Loc: H->getExceptionDecl()->getTypeSpecStartLoc(),
4400	DiagID: diag::warn_exception_caught_by_earlier_handler)
4401	<< H->getCaughtType();
4402	Diag(Loc: Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4403	DiagID: diag::note_previous_exception_handler)
4404	<< Problem->getCaughtType();
4405	}
4406	}
4407
4408	FSI->setHasCXXTry(TryLoc);
4409
4410	return CXXTryStmt::Create(C: Context, tryLoc: TryLoc, tryBlock: cast<CompoundStmt>(Val: TryBlock),
4411	handlers: Handlers);
4412	}
4413
4414	void Sema::DiagnoseExceptionUse(SourceLocation Loc, bool IsTry) {
4415	const llvm::Triple &T = Context.getTargetInfo().getTriple();
4416	const bool IsOpenMPGPUTarget =
4417	getLangOpts().OpenMPIsTargetDevice && (T.isNVPTX() || T.isAMDGCN());
4418
4419	// Don't report an error if 'try' is used in system headers or in an OpenMP
4420	// target region compiled for a GPU architecture.
4421	if (IsOpenMPGPUTarget || getLangOpts().CUDA)
4422	// Delay error emission for the OpenMP device code.
4423	return;
4424
4425	if (!getLangOpts().CXXExceptions &&
4426	!getSourceManager().isInSystemHeader(Loc) &&
4427	!CurContext->isDependentContext())
4428	targetDiag(Loc, DiagID: diag::err_exceptions_disabled) << (IsTry ? "try" : "throw");
4429	}
4430
4431	StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
4432	Stmt *TryBlock, Stmt *Handler) {
4433	assert(TryBlock && Handler);
4434
4435	sema::FunctionScopeInfo *FSI = getCurFunction();
4436
4437	// SEH __try is incompatible with C++ try. Borland appears to support this,
4438	// however.
4439	if (!getLangOpts().Borland) {
4440	if (FSI->FirstCXXOrObjCTryLoc.isValid()) {
4441	Diag(Loc: TryLoc, DiagID: diag::err_mixing_cxx_try_seh_try) << FSI->FirstTryType;
4442	Diag(Loc: FSI->FirstCXXOrObjCTryLoc, DiagID: diag::note_conflicting_try_here)
4443	<< (FSI->FirstTryType == sema::FunctionScopeInfo::TryLocIsCXX
4444	? "'try'"
4445	: "'@try'");
4446	}
4447	}
4448
4449	FSI->setHasSEHTry(TryLoc);
4450
4451	// Reject __try in Obj-C methods, blocks, and captured decls, since we don't
4452	// track if they use SEH.
4453	DeclContext *DC = CurContext;
4454	while (DC && !DC->isFunctionOrMethod())
4455	DC = DC->getParent();
4456	FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Val: DC);
4457	if (FD)
4458	FD->setUsesSEHTry(true);
4459	else
4460	Diag(Loc: TryLoc, DiagID: diag::err_seh_try_outside_functions);
4461
4462	// Reject __try on unsupported targets.
4463	if (!Context.getTargetInfo().isSEHTrySupported())
4464	Diag(Loc: TryLoc, DiagID: diag::err_seh_try_unsupported);
4465
4466	return SEHTryStmt::Create(C: Context, isCXXTry: IsCXXTry, TryLoc, TryBlock, Handler);
4467	}
4468
4469	StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
4470	Stmt *Block) {
4471	assert(FilterExpr && Block);
4472	QualType FTy = FilterExpr->getType();
4473	if (!FTy->isIntegerType() && !FTy->isDependentType()) {
4474	return StmtError(
4475	Diag(Loc: FilterExpr->getExprLoc(), DiagID: diag::err_filter_expression_integral)
4476	<< FTy);
4477	}
4478	return SEHExceptStmt::Create(C: Context, ExceptLoc: Loc, FilterExpr, Block);
4479	}
4480
4481	void Sema::ActOnStartSEHFinallyBlock() {
4482	CurrentSEHFinally.push_back(Elt: CurScope);
4483	}
4484
4485	void Sema::ActOnAbortSEHFinallyBlock() {
4486	CurrentSEHFinally.pop_back();
4487	}
4488
4489	StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
4490	assert(Block);
4491	CurrentSEHFinally.pop_back();
4492	return SEHFinallyStmt::Create(C: Context, FinallyLoc: Loc, Block);
4493	}
4494
4495	StmtResult
4496	Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
4497	Scope *SEHTryParent = CurScope;
4498	while (SEHTryParent && !SEHTryParent->isSEHTryScope())
4499	SEHTryParent = SEHTryParent->getParent();
4500	if (!SEHTryParent)
4501	return StmtError(Diag(Loc, DiagID: diag::err_ms___leave_not_in___try));
4502	CheckJumpOutOfSEHFinally(S&: *this, Loc, DestScope: *SEHTryParent);
4503
4504	return new (Context) SEHLeaveStmt(Loc);
4505	}
4506
4507	StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
4508	bool IsIfExists,
4509	NestedNameSpecifierLoc QualifierLoc,
4510	DeclarationNameInfo NameInfo,
4511	Stmt *Nested)
4512	{
4513	return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
4514	QualifierLoc, NameInfo,
4515	cast<CompoundStmt>(Val: Nested));
4516	}
4517
4518
4519	StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4520	bool IsIfExists,
4521	CXXScopeSpec &SS,
4522	UnqualifiedId &Name,
4523	Stmt *Nested) {
4524	return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4525	QualifierLoc: SS.getWithLocInContext(Context),
4526	NameInfo: GetNameFromUnqualifiedId(Name),
4527	Nested);
4528	}
4529
4530	RecordDecl*
4531	Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4532	unsigned NumParams) {
4533	DeclContext *DC = CurContext;
4534	while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4535	DC = DC->getParent();
4536
4537	RecordDecl *RD = nullptr;
4538	if (getLangOpts().CPlusPlus)
4539	RD = CXXRecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4540	/*Id=*/nullptr);
4541	else
4542	RD = RecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4543	/*Id=*/nullptr);
4544
4545	RD->setCapturedRecord();
4546	DC->addDecl(D: RD);
4547	RD->setImplicit();
4548	RD->startDefinition();
4549
4550	assert(NumParams > 0 && "CapturedStmt requires context parameter");
4551	CD = CapturedDecl::Create(C&: Context, DC: CurContext, NumParams);
4552	DC->addDecl(D: CD);
4553	return RD;
4554	}
4555
4556	static bool
4557	buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
4558	SmallVectorImpl<CapturedStmt::Capture> &Captures,
4559	SmallVectorImpl<Expr *> &CaptureInits) {
4560	for (const sema::Capture &Cap : RSI->Captures) {
4561	if (Cap.isInvalid())
4562	continue;
4563
4564	// Form the initializer for the capture.
4565	ExprResult Init = S.BuildCaptureInit(Capture: Cap, ImplicitCaptureLoc: Cap.getLocation(),
4566	IsOpenMPMapping: RSI->CapRegionKind == CR_OpenMP);
4567
4568	// FIXME: Bail out now if the capture is not used and the initializer has
4569	// no side-effects.
4570
4571	// Create a field for this capture.
4572	FieldDecl *Field = S.BuildCaptureField(RD: RSI->TheRecordDecl, Capture: Cap);
4573
4574	// Add the capture to our list of captures.
4575	if (Cap.isThisCapture()) {
4576	Captures.push_back(Elt: CapturedStmt::Capture(Cap.getLocation(),
4577	CapturedStmt::VCK_This));
4578	} else if (Cap.isVLATypeCapture()) {
4579	Captures.push_back(
4580	Elt: CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
4581	} else {
4582	assert(Cap.isVariableCapture() && "unknown kind of capture");
4583
4584	if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
4585	S.OpenMP().setOpenMPCaptureKind(FD: Field, D: Cap.getVariable(),
4586	Level: RSI->OpenMPLevel);
4587
4588	Captures.push_back(Elt: CapturedStmt::Capture(
4589	Cap.getLocation(),
4590	Cap.isReferenceCapture() ? CapturedStmt::VCK_ByRef
4591	: CapturedStmt::VCK_ByCopy,
4592	cast<VarDecl>(Val: Cap.getVariable())));
4593	}
4594	CaptureInits.push_back(Elt: Init.get());
4595	}
4596	return false;
4597	}
4598
4599	static std::optional<int>
4600	isOpenMPCapturedRegionInArmSMEFunction(Sema const &S, CapturedRegionKind Kind) {
4601	if (!S.getLangOpts().OpenMP || Kind != CR_OpenMP)
4602	return {};
4603	if (const FunctionDecl *FD = S.getCurFunctionDecl(/*AllowLambda=*/true)) {
4604	if (IsArmStreamingFunction(FD, /*IncludeLocallyStreaming=*/true))
4605	return /* in streaming functions */ 0;
4606	if (hasArmZAState(FD))
4607	return /* in functions with ZA state */ 1;
4608	if (hasArmZT0State(FD))
4609	return /* in fuctions with ZT0 state */ 2;
4610	}
4611	return {};
4612	}
4613
4614	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4615	CapturedRegionKind Kind,
4616	unsigned NumParams) {
4617	if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(S: *this, Kind))
4618	Diag(Loc, DiagID: diag::err_sme_openmp_captured_region) << *ErrorIndex;
4619
4620	CapturedDecl *CD = nullptr;
4621	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4622
4623	// Build the context parameter
4624	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4625	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4626	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(Decl: RD));
4627	auto *Param =
4628	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4629	ParamKind: ImplicitParamKind::CapturedContext);
4630	DC->addDecl(D: Param);
4631
4632	CD->setContextParam(i: 0, P: Param);
4633
4634	// Enter the capturing scope for this captured region.
4635	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind);
4636
4637	if (CurScope)
4638	PushDeclContext(S: CurScope, DC: CD);
4639	else
4640	CurContext = CD;
4641
4642	PushExpressionEvaluationContext(
4643	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4644	ExprEvalContexts.back().InImmediateEscalatingFunctionContext = false;
4645	}
4646
4647	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4648	CapturedRegionKind Kind,
4649	ArrayRef<CapturedParamNameType> Params,
4650	unsigned OpenMPCaptureLevel) {
4651	if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(S: *this, Kind))
4652	Diag(Loc, DiagID: diag::err_sme_openmp_captured_region) << *ErrorIndex;
4653
4654	CapturedDecl *CD = nullptr;
4655	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams: Params.size());
4656
4657	// Build the context parameter
4658	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4659	bool ContextIsFound = false;
4660	unsigned ParamNum = 0;
4661	for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4662	E = Params.end();
4663	I != E; ++I, ++ParamNum) {
4664	if (I->second.isNull()) {
4665	assert(!ContextIsFound &&
4666	"null type has been found already for '__context' parameter");
4667	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4668	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(Decl: RD))
4669	.withConst()
4670	.withRestrict();
4671	auto *Param =
4672	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4673	ParamKind: ImplicitParamKind::CapturedContext);
4674	DC->addDecl(D: Param);
4675	CD->setContextParam(i: ParamNum, P: Param);
4676	ContextIsFound = true;
4677	} else {
4678	IdentifierInfo *ParamName = &Context.Idents.get(Name: I->first);
4679	auto *Param =
4680	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: I->second,
4681	ParamKind: ImplicitParamKind::CapturedContext);
4682	DC->addDecl(D: Param);
4683	CD->setParam(i: ParamNum, P: Param);
4684	}
4685	}
4686	assert(ContextIsFound && "no null type for '__context' parameter");
4687	if (!ContextIsFound) {
4688	// Add __context implicitly if it is not specified.
4689	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4690	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(Decl: RD));
4691	auto *Param =
4692	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4693	ParamKind: ImplicitParamKind::CapturedContext);
4694	DC->addDecl(D: Param);
4695	CD->setContextParam(i: ParamNum, P: Param);
4696	}
4697	// Enter the capturing scope for this captured region.
4698	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind, OpenMPCaptureLevel);
4699
4700	if (CurScope)
4701	PushDeclContext(S: CurScope, DC: CD);
4702	else
4703	CurContext = CD;
4704
4705	PushExpressionEvaluationContext(
4706	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4707	}
4708
4709	void Sema::ActOnCapturedRegionError() {
4710	DiscardCleanupsInEvaluationContext();
4711	PopExpressionEvaluationContext();
4712	PopDeclContext();
4713	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4714	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4715
4716	RecordDecl *Record = RSI->TheRecordDecl;
4717	Record->setInvalidDecl();
4718
4719	SmallVector<Decl*, 4> Fields(Record->fields());
4720	ActOnFields(/*Scope=*/S: nullptr, RecLoc: Record->getLocation(), TagDecl: Record, Fields,
4721	LBrac: SourceLocation(), RBrac: SourceLocation(), AttrList: ParsedAttributesView());
4722	}
4723
4724	StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4725	// Leave the captured scope before we start creating captures in the
4726	// enclosing scope.
4727	DiscardCleanupsInEvaluationContext();
4728	PopExpressionEvaluationContext();
4729	PopDeclContext();
4730	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4731	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4732
4733	SmallVector<CapturedStmt::Capture, 4> Captures;
4734	SmallVector<Expr *, 4> CaptureInits;
4735	if (buildCapturedStmtCaptureList(S&: *this, RSI, Captures, CaptureInits))
4736	return StmtError();
4737
4738	CapturedDecl *CD = RSI->TheCapturedDecl;
4739	RecordDecl *RD = RSI->TheRecordDecl;
4740
4741	CapturedStmt *Res = CapturedStmt::Create(
4742	Context: getASTContext(), S, Kind: static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4743	Captures, CaptureInits, CD, RD);
4744
4745	CD->setBody(Res->getCapturedStmt());
4746	RD->completeDefinition();
4747
4748	return Res;
4749	}
4750