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(decl->getLocation(), 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(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, 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, diag::note_inequality_comparison_to_or_assign)
193	<< FixItHint::CreateReplacement(Loc, "|=");
194	else if (Kind == Equality)
195	S.Diag(Loc, diag::note_equality_comparison_to_assign)
196	<< FixItHint::CreateReplacement(Loc, "=");
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, diag::warn_unused_return_type)
212	<< IsCtor << A << OffendingDecl << false << R1 << R2;
213	if (IsCtor)
214	return S.Diag(Loc, diag::warn_unused_constructor)
215	<< A << false << R1 << R2;
216	return S.Diag(Loc, diag::warn_unused_result) << A << false << R1 << R2;
217	}
218
219	if (OffendingDecl)
220	return S.Diag(Loc, diag::warn_unused_return_type)
221	<< IsCtor << A << OffendingDecl << true << Msg << R1 << R2;
222	if (IsCtor)
223	return S.Diag(Loc, diag::warn_unused_constructor)
224	<< A << true << Msg << R1 << R2;
225	return S.Diag(Loc, 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	cast_or_null<WarnUnusedResultAttr>(A), Loc, R1, R2,
300	/*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, diag::warn_unused_call) << R1 << R2 << "pure";
312	return;
313	}
314	if (FD->hasAttr<ConstAttr>()) {
315	S.Diag(Loc, 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=*/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, TD, TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
335	R2, /*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, diag::err_arc_unused_init_message) << R1;
345	return;
346	}
347	const ObjCMethodDecl *MD = ME->getMethodDecl();
348	if (MD) {
349	if (DiagnoseNoDiscard(S, nullptr, MD->getAttr<WarnUnusedResultAttr>(),
350	Loc, R1, R2,
351	/*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>(Source))
362	DiagID = diag::warn_unused_container_subscript_expr;
363	else if (isa<ObjCPropertyRefExpr>(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, diag::warn_unused_voidptr)
391	<< FixItHint::CreateRemoval(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, 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) << 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(D->getLocation(), 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	ExprResult Converted = CorrectDelayedTyposInExpr(
539	ER: Val, /*InitDecl=*/nullptr, /*RecoverUncorrectedTypos=*/false,
540	Filter: CheckAndFinish);
541	if (Converted.get() == Val.get())
542	Converted = CheckAndFinish(Val.get());
543	return Converted;
544	}
545
546	StmtResult
547	Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
548	SourceLocation DotDotDotLoc, ExprResult RHSVal,
549	SourceLocation ColonLoc) {
550	assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value");
551	assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()
552	: RHSVal.isInvalid() || RHSVal.get()) &&
553	"missing RHS value");
554
555	if (getCurFunction()->SwitchStack.empty()) {
556	Diag(CaseLoc, diag::err_case_not_in_switch);
557	return StmtError();
558	}
559
560	if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
561	getCurFunction()->SwitchStack.back().setInt(true);
562	return StmtError();
563	}
564
565	if (LangOpts.OpenACC &&
566	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
567	Diag(CaseLoc, diag::err_acc_branch_in_out_compute_construct)
568	<< /*branch*/ 0 << /*into*/ 1;
569	return StmtError();
570	}
571
572	auto *CS = CaseStmt::Create(Ctx: Context, lhs: LHSVal.get(), rhs: RHSVal.get(),
573	caseLoc: CaseLoc, ellipsisLoc: DotDotDotLoc, colonLoc: ColonLoc);
574	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(CS);
575	return CS;
576	}
577
578	void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
579	cast<CaseStmt>(Val: S)->setSubStmt(SubStmt);
580	}
581
582	StmtResult
583	Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
584	Stmt *SubStmt, Scope *CurScope) {
585	if (getCurFunction()->SwitchStack.empty()) {
586	Diag(DefaultLoc, diag::err_default_not_in_switch);
587	return SubStmt;
588	}
589
590	if (LangOpts.OpenACC &&
591	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
592	Diag(DefaultLoc, diag::err_acc_branch_in_out_compute_construct)
593	<< /*branch*/ 0 << /*into*/ 1;
594	return StmtError();
595	}
596
597	DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
598	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: DS);
599	return DS;
600	}
601
602	StmtResult
603	Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
604	SourceLocation ColonLoc, Stmt *SubStmt) {
605	// If the label was multiply defined, reject it now.
606	if (TheDecl->getStmt()) {
607	Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
608	Diag(TheDecl->getLocation(), diag::note_previous_definition);
609	return SubStmt;
610	}
611
612	ReservedIdentifierStatus Status = TheDecl->isReserved(getLangOpts());
613	if (isReservedInAllContexts(Status) &&
614	!Context.getSourceManager().isInSystemHeader(IdentLoc))
615	Diag(IdentLoc, diag::warn_reserved_extern_symbol)
616	<< TheDecl << static_cast<int>(Status);
617
618	// If this label is in a compute construct scope, we need to make sure we
619	// check gotos in/out.
620	if (getCurScope()->isInOpenACCComputeConstructScope())
621	setFunctionHasBranchProtectedScope();
622
623	// OpenACC3.3 2.14.4:
624	// The update directive is executable. It must not appear in place of the
625	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
626	// C++.
627	if (isa<OpenACCUpdateConstruct>(Val: SubStmt)) {
628	Diag(SubStmt->getBeginLoc(), diag::err_acc_update_as_body) << /*Label*/ 4;
629	SubStmt = new (Context) NullStmt(SubStmt->getBeginLoc());
630	}
631
632	// Otherwise, things are good. Fill in the declaration and return it.
633	LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
634	TheDecl->setStmt(LS);
635	if (!TheDecl->isGnuLocal()) {
636	TheDecl->setLocStart(IdentLoc);
637	if (!TheDecl->isMSAsmLabel()) {
638	// Don't update the location of MS ASM labels. These will result in
639	// a diagnostic, and changing the location here will mess that up.
640	TheDecl->setLocation(IdentLoc);
641	}
642	}
643	return LS;
644	}
645
646	StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
647	ArrayRef<const Attr *> Attrs,
648	Stmt *SubStmt) {
649	// FIXME: this code should move when a planned refactoring around statement
650	// attributes lands.
651	for (const auto *A : Attrs) {
652	if (A->getKind() == attr::MustTail) {
653	if (!checkAndRewriteMustTailAttr(St: SubStmt, MTA: *A)) {
654	return SubStmt;
655	}
656	setFunctionHasMustTail();
657	}
658	}
659
660	return AttributedStmt::Create(C: Context, Loc: AttrsLoc, Attrs, SubStmt);
661	}
662
663	StmtResult Sema::ActOnAttributedStmt(const ParsedAttributes &Attrs,
664	Stmt *SubStmt) {
665	SmallVector<const Attr *, 1> SemanticAttrs;
666	ProcessStmtAttributes(Stmt: SubStmt, InAttrs: Attrs, OutAttrs&: SemanticAttrs);
667	if (!SemanticAttrs.empty())
668	return BuildAttributedStmt(AttrsLoc: Attrs.Range.getBegin(), Attrs: SemanticAttrs, SubStmt);
669	// If none of the attributes applied, that's fine, we can recover by
670	// returning the substatement directly instead of making an AttributedStmt
671	// with no attributes on it.
672	return SubStmt;
673	}
674
675	bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
676	ReturnStmt *R = cast<ReturnStmt>(Val: St);
677	Expr *E = R->getRetValue();
678
679	if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
680	// We have to suspend our check until template instantiation time.
681	return true;
682
683	if (!checkMustTailAttr(St, MTA))
684	return false;
685
686	// FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
687	// Currently it does not skip implicit constructors in an initialization
688	// context.
689	auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
690	return IgnoreExprNodes(E, Fns&: IgnoreImplicitAsWrittenSingleStep,
691	Fns&: IgnoreElidableImplicitConstructorSingleStep);
692	};
693
694	// Now that we have verified that 'musttail' is valid here, rewrite the
695	// return value to remove all implicit nodes, but retain parentheses.
696	R->setRetValue(IgnoreImplicitAsWritten(E));
697	return true;
698	}
699
700	bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
701	assert(!CurContext->isDependentContext() &&
702	"musttail cannot be checked from a dependent context");
703
704	// FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
705	auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
706	return IgnoreExprNodes(E: const_cast<Expr *>(E), Fns&: IgnoreParensSingleStep,
707	Fns&: IgnoreImplicitAsWrittenSingleStep,
708	Fns&: IgnoreElidableImplicitConstructorSingleStep);
709	};
710
711	const Expr *E = cast<ReturnStmt>(Val: St)->getRetValue();
712	const auto *CE = dyn_cast_or_null<CallExpr>(Val: IgnoreParenImplicitAsWritten(E));
713
714	if (!CE) {
715	Diag(St->getBeginLoc(), diag::err_musttail_needs_call) << &MTA;
716	return false;
717	}
718
719	if (const FunctionDecl *CalleeDecl = CE->getDirectCallee();
720	CalleeDecl && CalleeDecl->hasAttr<NotTailCalledAttr>()) {
721	Diag(St->getBeginLoc(), diag::err_musttail_mismatch) << /*show-function-callee=*/true << CalleeDecl;
722	Diag(CalleeDecl->getLocation(), diag::note_musttail_disabled_by_not_tail_called);
723	return false;
724	}
725
726	if (const auto *EWC = dyn_cast<ExprWithCleanups>(Val: E)) {
727	if (EWC->cleanupsHaveSideEffects()) {
728	Diag(St->getBeginLoc(), diag::err_musttail_needs_trivial_args) << &MTA;
729	return false;
730	}
731	}
732
733	// We need to determine the full function type (including "this" type, if any)
734	// for both caller and callee.
735	struct FuncType {
736	enum {
737	ft_non_member,
738	ft_static_member,
739	ft_non_static_member,
740	ft_pointer_to_member,
741	} MemberType = ft_non_member;
742
743	QualType This;
744	const FunctionProtoType *Func;
745	const CXXMethodDecl *Method = nullptr;
746	} CallerType, CalleeType;
747
748	auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
749	bool IsCallee) -> bool {
750	if (isa<CXXConstructorDecl, CXXDestructorDecl>(Val: CMD)) {
751	Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
752	<< IsCallee << isa<CXXDestructorDecl>(CMD);
753	if (IsCallee)
754	Diag(CMD->getBeginLoc(), diag::note_musttail_structors_forbidden)
755	<< isa<CXXDestructorDecl>(CMD);
756	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
757	return false;
758	}
759	if (CMD->isStatic())
760	Type.MemberType = FuncType::ft_static_member;
761	else {
762	Type.This = CMD->getFunctionObjectParameterType();
763	Type.MemberType = FuncType::ft_non_static_member;
764	}
765	Type.Func = CMD->getType()->castAs<FunctionProtoType>();
766	return true;
767	};
768
769	const auto *CallerDecl = dyn_cast<FunctionDecl>(Val: CurContext);
770
771	// Find caller function signature.
772	if (!CallerDecl) {
773	int ContextType;
774	if (isa<BlockDecl>(Val: CurContext))
775	ContextType = 0;
776	else if (isa<ObjCMethodDecl>(Val: CurContext))
777	ContextType = 1;
778	else
779	ContextType = 2;
780	Diag(St->getBeginLoc(), diag::err_musttail_forbidden_from_this_context)
781	<< &MTA << ContextType;
782	return false;
783	} else if (const auto *CMD = dyn_cast<CXXMethodDecl>(Val: CurContext)) {
784	// Caller is a class/struct method.
785	if (!GetMethodType(CMD, CallerType, false))
786	return false;
787	} else {
788	// Caller is a non-method function.
789	CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
790	}
791
792	const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
793	const auto *CalleeBinOp = dyn_cast<BinaryOperator>(Val: CalleeExpr);
794	SourceLocation CalleeLoc = CE->getCalleeDecl()
795	? CE->getCalleeDecl()->getBeginLoc()
796	: St->getBeginLoc();
797
798	// Find callee function signature.
799	if (const CXXMethodDecl *CMD =
800	dyn_cast_or_null<CXXMethodDecl>(Val: CE->getCalleeDecl())) {
801	// Call is: obj.method(), obj->method(), functor(), etc.
802	if (!GetMethodType(CMD, CalleeType, true))
803	return false;
804	} else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
805	// Call is: obj->*method_ptr or obj.*method_ptr
806	const auto *MPT =
807	CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
808	CalleeType.This =
809	Context.getTypeDeclType(MPT->getMostRecentCXXRecordDecl());
810	CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
811	CalleeType.MemberType = FuncType::ft_pointer_to_member;
812	} else if (isa<CXXPseudoDestructorExpr>(Val: CalleeExpr)) {
813	Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
814	<< /* IsCallee = */ 1 << /* IsDestructor = */ 1;
815	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
816	return false;
817	} else {
818	// Non-method function.
819	CalleeType.Func =
820	CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
821	}
822
823	// Both caller and callee must have a prototype (no K&R declarations).
824	if (!CalleeType.Func || !CallerType.Func) {
825	Diag(St->getBeginLoc(), diag::err_musttail_needs_prototype) << &MTA;
826	if (!CalleeType.Func && CE->getDirectCallee()) {
827	Diag(CE->getDirectCallee()->getBeginLoc(),
828	diag::note_musttail_fix_non_prototype);
829	}
830	if (!CallerType.Func)
831	Diag(CallerDecl->getBeginLoc(), diag::note_musttail_fix_non_prototype);
832	return false;
833	}
834
835	// Caller and callee must have matching calling conventions.
836	//
837	// Some calling conventions are physically capable of supporting tail calls
838	// even if the function types don't perfectly match. LLVM is currently too
839	// strict to allow this, but if LLVM added support for this in the future, we
840	// could exit early here and skip the remaining checks if the functions are
841	// using such a calling convention.
842	if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
843	if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
844	Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch)
845	<< true << ND->getDeclName();
846	else
847	Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch) << false;
848	Diag(CalleeLoc, diag::note_musttail_callconv_mismatch)
849	<< FunctionType::getNameForCallConv(CallerType.Func->getCallConv())
850	<< FunctionType::getNameForCallConv(CalleeType.Func->getCallConv());
851	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
852	return false;
853	}
854
855	if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
856	Diag(St->getBeginLoc(), diag::err_musttail_no_variadic) << &MTA;
857	return false;
858	}
859
860	const auto *CalleeDecl = CE->getCalleeDecl();
861	if (CalleeDecl && CalleeDecl->hasAttr<CXX11NoReturnAttr>()) {
862	Diag(St->getBeginLoc(), diag::err_musttail_no_return) << &MTA;
863	return false;
864	}
865
866	// Caller and callee must match in whether they have a "this" parameter.
867	if (CallerType.This.isNull() != CalleeType.This.isNull()) {
868	if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl())) {
869	Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
870	<< CallerType.MemberType << CalleeType.MemberType << true
871	<< ND->getDeclName();
872	Diag(CalleeLoc, diag::note_musttail_callee_defined_here)
873	<< ND->getDeclName();
874	} else
875	Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
876	<< CallerType.MemberType << CalleeType.MemberType << false;
877	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
878	return false;
879	}
880
881	auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
882	PartialDiagnostic &PD) -> bool {
883	enum {
884	ft_different_class,
885	ft_parameter_arity,
886	ft_parameter_mismatch,
887	ft_return_type,
888	};
889
890	auto DoTypesMatch = [this, &PD](QualType A, QualType B,
891	unsigned Select) -> bool {
892	if (!Context.hasSimilarType(T1: A, T2: B)) {
893	PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
894	return false;
895	}
896	return true;
897	};
898
899	if (!CallerType.This.isNull() &&
900	!DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
901	return false;
902
903	if (!DoTypesMatch(CallerType.Func->getReturnType(),
904	CalleeType.Func->getReturnType(), ft_return_type))
905	return false;
906
907	if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
908	PD << ft_parameter_arity << CallerType.Func->getNumParams()
909	<< CalleeType.Func->getNumParams();
910	return false;
911	}
912
913	ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
914	ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
915	size_t N = CallerType.Func->getNumParams();
916	for (size_t I = 0; I < N; I++) {
917	if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
918	ft_parameter_mismatch)) {
919	PD << static_cast<int>(I) + 1;
920	return false;
921	}
922	}
923
924	return true;
925	};
926
927	PartialDiagnostic PD = PDiag(diag::note_musttail_mismatch);
928	if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
929	if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
930	Diag(St->getBeginLoc(), diag::err_musttail_mismatch)
931	<< true << ND->getDeclName();
932	else
933	Diag(St->getBeginLoc(), diag::err_musttail_mismatch) << false;
934	Diag(CalleeLoc, PD);
935	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
936	return false;
937	}
938
939	// The lifetimes of locals and incoming function parameters must end before
940	// the call, because we can't have a stack frame to store them, so diagnose
941	// any pointers or references to them passed into the musttail call.
942	for (auto ArgExpr : CE->arguments()) {
943	InitializedEntity Entity = InitializedEntity::InitializeParameter(
944	Context, ArgExpr->getType(), false);
945	checkExprLifetimeMustTailArg(*this, Entity, const_cast<Expr *>(ArgExpr));
946	}
947
948	return true;
949	}
950
951	namespace {
952	class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
953	typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
954	Sema &SemaRef;
955	public:
956	CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
957	void VisitBinaryOperator(BinaryOperator *E) {
958	if (E->getOpcode() == BO_Comma)
959	SemaRef.DiagnoseCommaOperator(LHS: E->getLHS(), Loc: E->getExprLoc());
960	EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
961	}
962	};
963	}
964
965	StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc,
966	IfStatementKind StatementKind,
967	SourceLocation LParenLoc, Stmt *InitStmt,
968	ConditionResult Cond, SourceLocation RParenLoc,
969	Stmt *thenStmt, SourceLocation ElseLoc,
970	Stmt *elseStmt) {
971	if (Cond.isInvalid())
972	return StmtError();
973
974	bool ConstevalOrNegatedConsteval =
975	StatementKind == IfStatementKind::ConstevalNonNegated ||
976	StatementKind == IfStatementKind::ConstevalNegated;
977
978	Expr *CondExpr = Cond.get().second;
979	assert((CondExpr || ConstevalOrNegatedConsteval) &&
980	"If statement: missing condition");
981	// Only call the CommaVisitor when not C89 due to differences in scope flags.
982	if (CondExpr && (getLangOpts().C99 || getLangOpts().CPlusPlus) &&
983	!Diags.isIgnored(diag::warn_comma_operator, CondExpr->getExprLoc()))
984	CommaVisitor(*this).Visit(CondExpr);
985
986	if (!ConstevalOrNegatedConsteval && !elseStmt)
987	DiagnoseEmptyStmtBody(RParenLoc, thenStmt, diag::warn_empty_if_body);
988
989	if (ConstevalOrNegatedConsteval ||
990	StatementKind == IfStatementKind::Constexpr) {
991	auto DiagnoseLikelihood = [&](const Stmt *S) {
992	if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
993	Diags.Report(A->getLocation(),
994	diag::warn_attribute_has_no_effect_on_compile_time_if)
995	<< A << ConstevalOrNegatedConsteval << A->getRange();
996	Diags.Report(IfLoc,
997	diag::note_attribute_has_no_effect_on_compile_time_if_here)
998	<< ConstevalOrNegatedConsteval
999	<< SourceRange(IfLoc, (ConstevalOrNegatedConsteval
1000	? thenStmt->getBeginLoc()
1001	: LParenLoc)
1002	.getLocWithOffset(-1));
1003	}
1004	};
1005	DiagnoseLikelihood(thenStmt);
1006	DiagnoseLikelihood(elseStmt);
1007	} else {
1008	std::tuple<bool, const Attr *, const Attr *> LHC =
1009	Stmt::determineLikelihoodConflict(Then: thenStmt, Else: elseStmt);
1010	if (std::get<0>(t&: LHC)) {
1011	const Attr *ThenAttr = std::get<1>(t&: LHC);
1012	const Attr *ElseAttr = std::get<2>(t&: LHC);
1013	Diags.Report(ThenAttr->getLocation(),
1014	diag::warn_attributes_likelihood_ifstmt_conflict)
1015	<< ThenAttr << ThenAttr->getRange();
1016	Diags.Report(ElseAttr->getLocation(), diag::note_conflicting_attribute)
1017	<< ElseAttr << ElseAttr->getRange();
1018	}
1019	}
1020
1021	if (ConstevalOrNegatedConsteval) {
1022	bool Immediate = ExprEvalContexts.back().Context ==
1023	ExpressionEvaluationContext::ImmediateFunctionContext;
1024	if (CurContext->isFunctionOrMethod()) {
1025	const auto *FD =
1026	dyn_cast<FunctionDecl>(Val: Decl::castFromDeclContext(CurContext));
1027	if (FD && FD->isImmediateFunction())
1028	Immediate = true;
1029	}
1030	if (isUnevaluatedContext() || Immediate)
1031	Diags.Report(IfLoc, diag::warn_consteval_if_always_true) << Immediate;
1032	}
1033
1034	// OpenACC3.3 2.14.4:
1035	// The update directive is executable. It must not appear in place of the
1036	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1037	// C++.
1038	if (isa<OpenACCUpdateConstruct>(Val: thenStmt)) {
1039	Diag(thenStmt->getBeginLoc(), diag::err_acc_update_as_body) << /*if*/ 0;
1040	thenStmt = new (Context) NullStmt(thenStmt->getBeginLoc());
1041	}
1042
1043	return BuildIfStmt(IfLoc, StatementKind, LParenLoc, InitStmt, Cond, RParenLoc,
1044	ThenVal: thenStmt, ElseLoc, ElseVal: elseStmt);
1045	}
1046
1047	StmtResult Sema::BuildIfStmt(SourceLocation IfLoc,
1048	IfStatementKind StatementKind,
1049	SourceLocation LParenLoc, Stmt *InitStmt,
1050	ConditionResult Cond, SourceLocation RParenLoc,
1051	Stmt *thenStmt, SourceLocation ElseLoc,
1052	Stmt *elseStmt) {
1053	if (Cond.isInvalid())
1054	return StmtError();
1055
1056	if (StatementKind != IfStatementKind::Ordinary ||
1057	isa<ObjCAvailabilityCheckExpr>(Val: Cond.get().second))
1058	setFunctionHasBranchProtectedScope();
1059
1060	return IfStmt::Create(Ctx: Context, IL: IfLoc, Kind: StatementKind, Init: InitStmt,
1061	Var: Cond.get().first, Cond: Cond.get().second, LPL: LParenLoc,
1062	RPL: RParenLoc, Then: thenStmt, EL: ElseLoc, Else: elseStmt);
1063	}
1064
1065	namespace {
1066	struct CaseCompareFunctor {
1067	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1068	const llvm::APSInt &RHS) {
1069	return LHS.first < RHS;
1070	}
1071	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1072	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1073	return LHS.first < RHS.first;
1074	}
1075	bool operator()(const llvm::APSInt &LHS,
1076	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1077	return LHS < RHS.first;
1078	}
1079	};
1080	}
1081
1082	/// CmpCaseVals - Comparison predicate for sorting case values.
1083	///
1084	static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
1085	const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
1086	if (lhs.first < rhs.first)
1087	return true;
1088
1089	if (lhs.first == rhs.first &&
1090	lhs.second->getCaseLoc() < rhs.second->getCaseLoc())
1091	return true;
1092	return false;
1093	}
1094
1095	/// CmpEnumVals - Comparison predicate for sorting enumeration values.
1096	///
1097	static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1098	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1099	{
1100	return lhs.first < rhs.first;
1101	}
1102
1103	/// EqEnumVals - Comparison preficate for uniqing enumeration values.
1104	///
1105	static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1106	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1107	{
1108	return lhs.first == rhs.first;
1109	}
1110
1111	/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
1112	/// potentially integral-promoted expression @p expr.
1113	static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
1114	if (const auto *FE = dyn_cast<FullExpr>(Val: E))
1115	E = FE->getSubExpr();
1116	while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(Val: E)) {
1117	if (ImpCast->getCastKind() != CK_IntegralCast) break;
1118	E = ImpCast->getSubExpr();
1119	}
1120	return E->getType();
1121	}
1122
1123	ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
1124	class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
1125	Expr *Cond;
1126
1127	public:
1128	SwitchConvertDiagnoser(Expr *Cond)
1129	: ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
1130	Cond(Cond) {}
1131
1132	SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
1133	QualType T) override {
1134	return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
1135	}
1136
1137	SemaDiagnosticBuilder diagnoseIncomplete(
1138	Sema &S, SourceLocation Loc, QualType T) override {
1139	return S.Diag(Loc, diag::err_switch_incomplete_class_type)
1140	<< T << Cond->getSourceRange();
1141	}
1142
1143	SemaDiagnosticBuilder diagnoseExplicitConv(
1144	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1145	return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
1146	}
1147
1148	SemaDiagnosticBuilder noteExplicitConv(
1149	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1150	return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1151	<< ConvTy->isEnumeralType() << ConvTy;
1152	}
1153
1154	SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
1155	QualType T) override {
1156	return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
1157	}
1158
1159	SemaDiagnosticBuilder noteAmbiguous(
1160	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1161	return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1162	<< ConvTy->isEnumeralType() << ConvTy;
1163	}
1164
1165	SemaDiagnosticBuilder diagnoseConversion(
1166	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1167	llvm_unreachable("conversion functions are permitted");
1168	}
1169	} SwitchDiagnoser(Cond);
1170
1171	ExprResult CondResult =
1172	PerformContextualImplicitConversion(Loc: SwitchLoc, FromE: Cond, Converter&: SwitchDiagnoser);
1173	if (CondResult.isInvalid())
1174	return ExprError();
1175
1176	// FIXME: PerformContextualImplicitConversion doesn't always tell us if it
1177	// failed and produced a diagnostic.
1178	Cond = CondResult.get();
1179	if (!Cond->isTypeDependent() &&
1180	!Cond->getType()->isIntegralOrEnumerationType())
1181	return ExprError();
1182
1183	// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
1184	return UsualUnaryConversions(E: Cond);
1185	}
1186
1187	StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
1188	SourceLocation LParenLoc,
1189	Stmt *InitStmt, ConditionResult Cond,
1190	SourceLocation RParenLoc) {
1191	Expr *CondExpr = Cond.get().second;
1192	assert((Cond.isInvalid() || CondExpr) && "switch with no condition");
1193
1194	if (CondExpr && !CondExpr->isTypeDependent()) {
1195	// We have already converted the expression to an integral or enumeration
1196	// type, when we parsed the switch condition. There are cases where we don't
1197	// have an appropriate type, e.g. a typo-expr Cond was corrected to an
1198	// inappropriate-type expr, we just return an error.
1199	if (!CondExpr->getType()->isIntegralOrEnumerationType())
1200	return StmtError();
1201	if (CondExpr->isKnownToHaveBooleanValue()) {
1202	// switch(bool_expr) {...} is often a programmer error, e.g.
1203	// switch(n && mask) { ... } // Doh - should be "n & mask".
1204	// One can always use an if statement instead of switch(bool_expr).
1205	Diag(SwitchLoc, diag::warn_bool_switch_condition)
1206	<< CondExpr->getSourceRange();
1207	}
1208	}
1209
1210	setFunctionHasBranchIntoScope();
1211
1212	auto *SS = SwitchStmt::Create(Ctx: Context, Init: InitStmt, Var: Cond.get().first, Cond: CondExpr,
1213	LParenLoc, RParenLoc);
1214	getCurFunction()->SwitchStack.push_back(
1215	Elt: FunctionScopeInfo::SwitchInfo(SS, false));
1216	return SS;
1217	}
1218
1219	static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
1220	Val = Val.extOrTrunc(width: BitWidth);
1221	Val.setIsSigned(IsSigned);
1222	}
1223
1224	/// Check the specified case value is in range for the given unpromoted switch
1225	/// type.
1226	static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
1227	unsigned UnpromotedWidth, bool UnpromotedSign) {
1228	// In C++11 onwards, this is checked by the language rules.
1229	if (S.getLangOpts().CPlusPlus11)
1230	return;
1231
1232	// If the case value was signed and negative and the switch expression is
1233	// unsigned, don't bother to warn: this is implementation-defined behavior.
1234	// FIXME: Introduce a second, default-ignored warning for this case?
1235	if (UnpromotedWidth < Val.getBitWidth()) {
1236	llvm::APSInt ConvVal(Val);
1237	AdjustAPSInt(Val&: ConvVal, BitWidth: UnpromotedWidth, IsSigned: UnpromotedSign);
1238	AdjustAPSInt(Val&: ConvVal, BitWidth: Val.getBitWidth(), IsSigned: Val.isSigned());
1239	// FIXME: Use different diagnostics for overflow in conversion to promoted
1240	// type versus "switch expression cannot have this value". Use proper
1241	// IntRange checking rather than just looking at the unpromoted type here.
1242	if (ConvVal != Val)
1243	S.Diag(Loc, diag::warn_case_value_overflow) << toString(Val, 10)
1244	<< toString(ConvVal, 10);
1245	}
1246	}
1247
1248	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
1249
1250	/// Returns true if we should emit a diagnostic about this case expression not
1251	/// being a part of the enum used in the switch controlling expression.
1252	static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
1253	const EnumDecl *ED,
1254	const Expr *CaseExpr,
1255	EnumValsTy::iterator &EI,
1256	EnumValsTy::iterator &EIEnd,
1257	const llvm::APSInt &Val) {
1258	if (!ED->isClosed())
1259	return false;
1260
1261	if (const DeclRefExpr *DRE =
1262	dyn_cast<DeclRefExpr>(Val: CaseExpr->IgnoreParenImpCasts())) {
1263	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: DRE->getDecl())) {
1264	QualType VarType = VD->getType();
1265	QualType EnumType = S.Context.getTypeDeclType(ED);
1266	if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
1267	S.Context.hasSameUnqualifiedType(T1: EnumType, T2: VarType))
1268	return false;
1269	}
1270	}
1271
1272	if (ED->hasAttr<FlagEnumAttr>())
1273	return !S.IsValueInFlagEnum(ED, Val, AllowMask: false);
1274
1275	while (EI != EIEnd && EI->first < Val)
1276	EI++;
1277
1278	if (EI != EIEnd && EI->first == Val)
1279	return false;
1280
1281	return true;
1282	}
1283
1284	static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
1285	const Expr *Case) {
1286	QualType CondType = Cond->getType();
1287	QualType CaseType = Case->getType();
1288
1289	const EnumType *CondEnumType = CondType->getAs<EnumType>();
1290	const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
1291	if (!CondEnumType || !CaseEnumType)
1292	return;
1293
1294	// Ignore anonymous enums.
1295	if (!CondEnumType->getDecl()->getIdentifier() &&
1296	!CondEnumType->getDecl()->getTypedefNameForAnonDecl())
1297	return;
1298	if (!CaseEnumType->getDecl()->getIdentifier() &&
1299	!CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
1300	return;
1301
1302	if (S.Context.hasSameUnqualifiedType(T1: CondType, T2: CaseType))
1303	return;
1304
1305	S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types_switch)
1306	<< CondType << CaseType << Cond->getSourceRange()
1307	<< Case->getSourceRange();
1308	}
1309
1310	StmtResult
1311	Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
1312	Stmt *BodyStmt) {
1313	SwitchStmt *SS = cast<SwitchStmt>(Val: Switch);
1314	bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
1315	assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&
1316	"switch stack missing push/pop!");
1317
1318	getCurFunction()->SwitchStack.pop_back();
1319
1320	if (!BodyStmt) return StmtError();
1321
1322	// OpenACC3.3 2.14.4:
1323	// The update directive is executable. It must not appear in place of the
1324	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1325	// C++.
1326	if (isa<OpenACCUpdateConstruct>(Val: BodyStmt)) {
1327	Diag(BodyStmt->getBeginLoc(), diag::err_acc_update_as_body) << /*switch*/ 3;
1328	BodyStmt = new (Context) NullStmt(BodyStmt->getBeginLoc());
1329	}
1330
1331	SS->setBody(S: BodyStmt, SL: SwitchLoc);
1332
1333	Expr *CondExpr = SS->getCond();
1334	if (!CondExpr) return StmtError();
1335
1336	QualType CondType = CondExpr->getType();
1337
1338	// C++ 6.4.2.p2:
1339	// Integral promotions are performed (on the switch condition).
1340	//
1341	// A case value unrepresentable by the original switch condition
1342	// type (before the promotion) doesn't make sense, even when it can
1343	// be represented by the promoted type. Therefore we need to find
1344	// the pre-promotion type of the switch condition.
1345	const Expr *CondExprBeforePromotion = CondExpr;
1346	QualType CondTypeBeforePromotion =
1347	GetTypeBeforeIntegralPromotion(E&: CondExprBeforePromotion);
1348
1349	// Get the bitwidth of the switched-on value after promotions. We must
1350	// convert the integer case values to this width before comparison.
1351	bool HasDependentValue
1352	= CondExpr->isTypeDependent() || CondExpr->isValueDependent();
1353	unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(T: CondType);
1354	bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
1355
1356	// Get the width and signedness that the condition might actually have, for
1357	// warning purposes.
1358	// FIXME: Grab an IntRange for the condition rather than using the unpromoted
1359	// type.
1360	unsigned CondWidthBeforePromotion
1361	= HasDependentValue ? 0 : Context.getIntWidth(T: CondTypeBeforePromotion);
1362	bool CondIsSignedBeforePromotion
1363	= CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
1364
1365	// Accumulate all of the case values in a vector so that we can sort them
1366	// and detect duplicates. This vector contains the APInt for the case after
1367	// it has been converted to the condition type.
1368	typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
1369	CaseValsTy CaseVals;
1370
1371	// Keep track of any GNU case ranges we see. The APSInt is the low value.
1372	typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
1373	CaseRangesTy CaseRanges;
1374
1375	DefaultStmt *TheDefaultStmt = nullptr;
1376
1377	bool CaseListIsErroneous = false;
1378
1379	// FIXME: We'd better diagnose missing or duplicate default labels even
1380	// in the dependent case. Because default labels themselves are never
1381	// dependent.
1382	for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
1383	SC = SC->getNextSwitchCase()) {
1384
1385	if (DefaultStmt *DS = dyn_cast<DefaultStmt>(Val: SC)) {
1386	if (TheDefaultStmt) {
1387	Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
1388	Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
1389
1390	// FIXME: Remove the default statement from the switch block so that
1391	// we'll return a valid AST. This requires recursing down the AST and
1392	// finding it, not something we are set up to do right now. For now,
1393	// just lop the entire switch stmt out of the AST.
1394	CaseListIsErroneous = true;
1395	}
1396	TheDefaultStmt = DS;
1397
1398	} else {
1399	CaseStmt *CS = cast<CaseStmt>(Val: SC);
1400
1401	Expr *Lo = CS->getLHS();
1402
1403	if (Lo->isValueDependent()) {
1404	HasDependentValue = true;
1405	break;
1406	}
1407
1408	// We already verified that the expression has a constant value;
1409	// get that value (prior to conversions).
1410	const Expr *LoBeforePromotion = Lo;
1411	GetTypeBeforeIntegralPromotion(E&: LoBeforePromotion);
1412	llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1413
1414	// Check the unconverted value is within the range of possible values of
1415	// the switch expression.
1416	checkCaseValue(*this, Lo->getBeginLoc(), LoVal, CondWidthBeforePromotion,
1417	CondIsSignedBeforePromotion);
1418
1419	// FIXME: This duplicates the check performed for warn_not_in_enum below.
1420	checkEnumTypesInSwitchStmt(S&: *this, Cond: CondExprBeforePromotion,
1421	Case: LoBeforePromotion);
1422
1423	// Convert the value to the same width/sign as the condition.
1424	AdjustAPSInt(Val&: LoVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1425
1426	// If this is a case range, remember it in CaseRanges, otherwise CaseVals.
1427	if (CS->getRHS()) {
1428	if (CS->getRHS()->isValueDependent()) {
1429	HasDependentValue = true;
1430	break;
1431	}
1432	CaseRanges.push_back(x: std::make_pair(x&: LoVal, y&: CS));
1433	} else
1434	CaseVals.push_back(Elt: std::make_pair(x&: LoVal, y&: CS));
1435	}
1436	}
1437
1438	if (!HasDependentValue) {
1439	// If we don't have a default statement, check whether the
1440	// condition is constant.
1441	llvm::APSInt ConstantCondValue;
1442	bool HasConstantCond = false;
1443	if (!TheDefaultStmt) {
1444	Expr::EvalResult Result;
1445	HasConstantCond = CondExpr->EvaluateAsInt(Result, Ctx: Context,
1446	AllowSideEffects: Expr::SE_AllowSideEffects);
1447	if (Result.Val.isInt())
1448	ConstantCondValue = Result.Val.getInt();
1449	assert(!HasConstantCond ||
1450	(ConstantCondValue.getBitWidth() == CondWidth &&
1451	ConstantCondValue.isSigned() == CondIsSigned));
1452	Diag(SwitchLoc, diag::warn_switch_default);
1453	}
1454	bool ShouldCheckConstantCond = HasConstantCond;
1455
1456	// Sort all the scalar case values so we can easily detect duplicates.
1457	llvm::stable_sort(Range&: CaseVals, C: CmpCaseVals);
1458
1459	if (!CaseVals.empty()) {
1460	for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
1461	if (ShouldCheckConstantCond &&
1462	CaseVals[i].first == ConstantCondValue)
1463	ShouldCheckConstantCond = false;
1464
1465	if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
1466	// If we have a duplicate, report it.
1467	// First, determine if either case value has a name
1468	StringRef PrevString, CurrString;
1469	Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
1470	Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
1471	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: PrevCase)) {
1472	PrevString = DeclRef->getDecl()->getName();
1473	}
1474	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: CurrCase)) {
1475	CurrString = DeclRef->getDecl()->getName();
1476	}
1477	SmallString<16> CaseValStr;
1478	CaseVals[i-1].first.toString(Str&: CaseValStr);
1479
1480	if (PrevString == CurrString)
1481	Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1482	diag::err_duplicate_case)
1483	<< (PrevString.empty() ? CaseValStr.str() : PrevString);
1484	else
1485	Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1486	diag::err_duplicate_case_differing_expr)
1487	<< (PrevString.empty() ? CaseValStr.str() : PrevString)
1488	<< (CurrString.empty() ? CaseValStr.str() : CurrString)
1489	<< CaseValStr;
1490
1491	Diag(CaseVals[i - 1].second->getLHS()->getBeginLoc(),
1492	diag::note_duplicate_case_prev);
1493	// FIXME: We really want to remove the bogus case stmt from the
1494	// substmt, but we have no way to do this right now.
1495	CaseListIsErroneous = true;
1496	}
1497	}
1498	}
1499
1500	// Detect duplicate case ranges, which usually don't exist at all in
1501	// the first place.
1502	if (!CaseRanges.empty()) {
1503	// Sort all the case ranges by their low value so we can easily detect
1504	// overlaps between ranges.
1505	llvm::stable_sort(Range&: CaseRanges);
1506
1507	// Scan the ranges, computing the high values and removing empty ranges.
1508	std::vector<llvm::APSInt> HiVals;
1509	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1510	llvm::APSInt &LoVal = CaseRanges[i].first;
1511	CaseStmt *CR = CaseRanges[i].second;
1512	Expr *Hi = CR->getRHS();
1513
1514	const Expr *HiBeforePromotion = Hi;
1515	GetTypeBeforeIntegralPromotion(E&: HiBeforePromotion);
1516	llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1517
1518	// Check the unconverted value is within the range of possible values of
1519	// the switch expression.
1520	checkCaseValue(*this, Hi->getBeginLoc(), HiVal,
1521	CondWidthBeforePromotion, CondIsSignedBeforePromotion);
1522
1523	// Convert the value to the same width/sign as the condition.
1524	AdjustAPSInt(Val&: HiVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1525
1526	// If the low value is bigger than the high value, the case is empty.
1527	if (LoVal > HiVal) {
1528	Diag(CR->getLHS()->getBeginLoc(), diag::warn_case_empty_range)
1529	<< SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
1530	CaseRanges.erase(position: CaseRanges.begin()+i);
1531	--i;
1532	--e;
1533	continue;
1534	}
1535
1536	if (ShouldCheckConstantCond &&
1537	LoVal <= ConstantCondValue &&
1538	ConstantCondValue <= HiVal)
1539	ShouldCheckConstantCond = false;
1540
1541	HiVals.push_back(x: HiVal);
1542	}
1543
1544	// Rescan the ranges, looking for overlap with singleton values and other
1545	// ranges. Since the range list is sorted, we only need to compare case
1546	// ranges with their neighbors.
1547	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1548	llvm::APSInt &CRLo = CaseRanges[i].first;
1549	llvm::APSInt &CRHi = HiVals[i];
1550	CaseStmt *CR = CaseRanges[i].second;
1551
1552	// Check to see whether the case range overlaps with any
1553	// singleton cases.
1554	CaseStmt *OverlapStmt = nullptr;
1555	llvm::APSInt OverlapVal(32);
1556
1557	// Find the smallest value >= the lower bound. If I is in the
1558	// case range, then we have overlap.
1559	CaseValsTy::iterator I =
1560	llvm::lower_bound(Range&: CaseVals, Value&: CRLo, C: CaseCompareFunctor());
1561	if (I != CaseVals.end() && I->first < CRHi) {
1562	OverlapVal = I->first; // Found overlap with scalar.
1563	OverlapStmt = I->second;
1564	}
1565
1566	// Find the smallest value bigger than the upper bound.
1567	I = std::upper_bound(first: I, last: CaseVals.end(), val: CRHi, comp: CaseCompareFunctor());
1568	if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1569	OverlapVal = (I-1)->first; // Found overlap with scalar.
1570	OverlapStmt = (I-1)->second;
1571	}
1572
1573	// Check to see if this case stmt overlaps with the subsequent
1574	// case range.
1575	if (i && CRLo <= HiVals[i-1]) {
1576	OverlapVal = HiVals[i-1]; // Found overlap with range.
1577	OverlapStmt = CaseRanges[i-1].second;
1578	}
1579
1580	if (OverlapStmt) {
1581	// If we have a duplicate, report it.
1582	Diag(CR->getLHS()->getBeginLoc(), diag::err_duplicate_case)
1583	<< toString(OverlapVal, 10);
1584	Diag(OverlapStmt->getLHS()->getBeginLoc(),
1585	diag::note_duplicate_case_prev);
1586	// FIXME: We really want to remove the bogus case stmt from the
1587	// substmt, but we have no way to do this right now.
1588	CaseListIsErroneous = true;
1589	}
1590	}
1591	}
1592
1593	// Complain if we have a constant condition and we didn't find a match.
1594	if (!CaseListIsErroneous && !CaseListIsIncomplete &&
1595	ShouldCheckConstantCond) {
1596	// TODO: it would be nice if we printed enums as enums, chars as
1597	// chars, etc.
1598	Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1599	<< toString(ConstantCondValue, 10)
1600	<< CondExpr->getSourceRange();
1601	}
1602
1603	// Check to see if switch is over an Enum and handles all of its
1604	// values. We only issue a warning if there is not 'default:', but
1605	// we still do the analysis to preserve this information in the AST
1606	// (which can be used by flow-based analyes).
1607	//
1608	const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1609
1610	// If switch has default case, then ignore it.
1611	if (!CaseListIsErroneous && !CaseListIsIncomplete && !HasConstantCond &&
1612	ET && ET->getDecl()->isCompleteDefinition() &&
1613	!ET->getDecl()->enumerators().empty()) {
1614	const EnumDecl *ED = ET->getDecl();
1615	EnumValsTy EnumVals;
1616
1617	// Gather all enum values, set their type and sort them,
1618	// allowing easier comparison with CaseVals.
1619	for (auto *EDI : ED->enumerators()) {
1620	llvm::APSInt Val = EDI->getInitVal();
1621	AdjustAPSInt(Val, BitWidth: CondWidth, IsSigned: CondIsSigned);
1622	EnumVals.push_back(Elt: std::make_pair(x&: Val, y&: EDI));
1623	}
1624	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1625	auto EI = EnumVals.begin(), EIEnd = llvm::unique(R&: EnumVals, P: EqEnumVals);
1626
1627	// See which case values aren't in enum.
1628	for (CaseValsTy::const_iterator CI = CaseVals.begin();
1629	CI != CaseVals.end(); CI++) {
1630	Expr *CaseExpr = CI->second->getLHS();
1631	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1632	CI->first))
1633	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1634	<< CondTypeBeforePromotion;
1635	}
1636
1637	// See which of case ranges aren't in enum
1638	EI = EnumVals.begin();
1639	for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1640	RI != CaseRanges.end(); RI++) {
1641	Expr *CaseExpr = RI->second->getLHS();
1642	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1643	RI->first))
1644	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1645	<< CondTypeBeforePromotion;
1646
1647	llvm::APSInt Hi =
1648	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1649	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1650
1651	CaseExpr = RI->second->getRHS();
1652	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1653	Hi))
1654	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1655	<< CondTypeBeforePromotion;
1656	}
1657
1658	// Check which enum vals aren't in switch
1659	auto CI = CaseVals.begin();
1660	auto RI = CaseRanges.begin();
1661	bool hasCasesNotInSwitch = false;
1662
1663	SmallVector<DeclarationName,8> UnhandledNames;
1664
1665	for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
1666	// Don't warn about omitted unavailable EnumConstantDecls.
1667	switch (EI->second->getAvailability()) {
1668	case AR_Deprecated:
1669	// Deprecated enumerators need to be handled: they may be deprecated,
1670	// but can still occur.
1671	break;
1672
1673	case AR_Unavailable:
1674	// Omitting an unavailable enumerator is ok; it should never occur.
1675	continue;
1676
1677	case AR_NotYetIntroduced:
1678	// Partially available enum constants should be present. Note that we
1679	// suppress -Wunguarded-availability diagnostics for such uses.
1680	case AR_Available:
1681	break;
1682	}
1683
1684	if (EI->second->hasAttr<UnusedAttr>())
1685	continue;
1686
1687	// Drop unneeded case values
1688	while (CI != CaseVals.end() && CI->first < EI->first)
1689	CI++;
1690
1691	if (CI != CaseVals.end() && CI->first == EI->first)
1692	continue;
1693
1694	// Drop unneeded case ranges
1695	for (; RI != CaseRanges.end(); RI++) {
1696	llvm::APSInt Hi =
1697	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1698	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1699	if (EI->first <= Hi)
1700	break;
1701	}
1702
1703	if (RI == CaseRanges.end() || EI->first < RI->first) {
1704	hasCasesNotInSwitch = true;
1705	UnhandledNames.push_back(Elt: EI->second->getDeclName());
1706	}
1707	}
1708
1709	if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1710	Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1711
1712	// Produce a nice diagnostic if multiple values aren't handled.
1713	if (!UnhandledNames.empty()) {
1714	auto DB = Diag(CondExpr->getExprLoc(), TheDefaultStmt
1715	? diag::warn_def_missing_case
1716	: diag::warn_missing_case)
1717	<< CondExpr->getSourceRange() << (int)UnhandledNames.size();
1718
1719	for (size_t I = 0, E = std::min(a: UnhandledNames.size(), b: (size_t)3);
1720	I != E; ++I)
1721	DB << UnhandledNames[I];
1722	}
1723
1724	if (!hasCasesNotInSwitch)
1725	SS->setAllEnumCasesCovered();
1726	}
1727	}
1728
1729	if (BodyStmt)
1730	DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), BodyStmt,
1731	diag::warn_empty_switch_body);
1732
1733	// FIXME: If the case list was broken is some way, we don't have a good system
1734	// to patch it up. Instead, just return the whole substmt as broken.
1735	if (CaseListIsErroneous)
1736	return StmtError();
1737
1738	return SS;
1739	}
1740
1741	void
1742	Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1743	Expr *SrcExpr) {
1744
1745	const auto *ET = DstType->getAs<EnumType>();
1746	if (!ET)
1747	return;
1748
1749	if (!SrcType->isIntegerType() ||
1750	Context.hasSameUnqualifiedType(T1: SrcType, T2: DstType))
1751	return;
1752
1753	if (SrcExpr->isTypeDependent() || SrcExpr->isValueDependent())
1754	return;
1755
1756	const EnumDecl *ED = ET->getDecl();
1757	if (!ED->isClosed())
1758	return;
1759
1760	if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1761	return;
1762
1763	std::optional<llvm::APSInt> RHSVal = SrcExpr->getIntegerConstantExpr(Ctx: Context);
1764	if (!RHSVal)
1765	return;
1766
1767	// Get the bitwidth of the enum value before promotions.
1768	unsigned DstWidth = Context.getIntWidth(T: DstType);
1769	bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1770	AdjustAPSInt(Val&: *RHSVal, BitWidth: DstWidth, IsSigned: DstIsSigned);
1771
1772	if (ED->hasAttr<FlagEnumAttr>()) {
1773	if (!IsValueInFlagEnum(ED, *RHSVal, /*AllowMask=*/true))
1774	Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1775	<< DstType.getUnqualifiedType();
1776	return;
1777	}
1778
1779	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1780	EnumValsTy;
1781	EnumValsTy EnumVals;
1782
1783	// Gather all enum values, set their type and sort them,
1784	// allowing easier comparison with rhs constant.
1785	for (auto *EDI : ED->enumerators()) {
1786	llvm::APSInt Val = EDI->getInitVal();
1787	AdjustAPSInt(Val, BitWidth: DstWidth, IsSigned: DstIsSigned);
1788	EnumVals.emplace_back(Args&: Val, Args&: EDI);
1789	}
1790	if (EnumVals.empty())
1791	return;
1792	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1793	EnumValsTy::iterator EIend = llvm::unique(R&: EnumVals, P: EqEnumVals);
1794
1795	// See which values aren't in the enum.
1796	EnumValsTy::const_iterator EI = EnumVals.begin();
1797	while (EI != EIend && EI->first < *RHSVal)
1798	EI++;
1799	if (EI == EIend || EI->first != *RHSVal) {
1800	Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1801	<< DstType.getUnqualifiedType();
1802	}
1803	}
1804
1805	StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
1806	SourceLocation LParenLoc, ConditionResult Cond,
1807	SourceLocation RParenLoc, Stmt *Body) {
1808	if (Cond.isInvalid())
1809	return StmtError();
1810
1811	auto CondVal = Cond.get();
1812	CheckBreakContinueBinding(E: CondVal.second);
1813
1814	if (CondVal.second &&
1815	!Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
1816	CommaVisitor(*this).Visit(CondVal.second);
1817
1818	// OpenACC3.3 2.14.4:
1819	// The update directive is executable. It must not appear in place of the
1820	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1821	// C++.
1822	if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1823	Diag(Body->getBeginLoc(), diag::err_acc_update_as_body) << /*while*/ 1;
1824	Body = new (Context) NullStmt(Body->getBeginLoc());
1825	}
1826
1827	if (isa<NullStmt>(Val: Body))
1828	getCurCompoundScope().setHasEmptyLoopBodies();
1829
1830	return WhileStmt::Create(Ctx: Context, Var: CondVal.first, Cond: CondVal.second, Body,
1831	WL: WhileLoc, LParenLoc, RParenLoc);
1832	}
1833
1834	StmtResult
1835	Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1836	SourceLocation WhileLoc, SourceLocation CondLParen,
1837	Expr *Cond, SourceLocation CondRParen) {
1838	assert(Cond && "ActOnDoStmt(): missing expression");
1839
1840	CheckBreakContinueBinding(E: Cond);
1841	ExprResult CondResult = CheckBooleanCondition(Loc: DoLoc, E: Cond);
1842	if (CondResult.isInvalid())
1843	return StmtError();
1844	Cond = CondResult.get();
1845
1846	CondResult = ActOnFinishFullExpr(Expr: Cond, CC: DoLoc, /*DiscardedValue*/ false);
1847	if (CondResult.isInvalid())
1848	return StmtError();
1849	Cond = CondResult.get();
1850
1851	// Only call the CommaVisitor for C89 due to differences in scope flags.
1852	if (Cond && !getLangOpts().C99 && !getLangOpts().CPlusPlus &&
1853	!Diags.isIgnored(diag::warn_comma_operator, Cond->getExprLoc()))
1854	CommaVisitor(*this).Visit(Cond);
1855
1856	// OpenACC3.3 2.14.4:
1857	// The update directive is executable. It must not appear in place of the
1858	// statement following an 'if', 'while', 'do', 'switch', or 'label' in C or
1859	// C++.
1860	if (isa<OpenACCUpdateConstruct>(Val: Body)) {
1861	Diag(Body->getBeginLoc(), diag::err_acc_update_as_body) << /*do*/ 2;
1862	Body = new (Context) NullStmt(Body->getBeginLoc());
1863	}
1864
1865	return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1866	}
1867
1868	namespace {
1869	// Use SetVector since the diagnostic cares about the ordering of the Decl's.
1870	using DeclSetVector = llvm::SmallSetVector<VarDecl *, 8>;
1871
1872	// This visitor will traverse a conditional statement and store all
1873	// the evaluated decls into a vector. Simple is set to true if none
1874	// of the excluded constructs are used.
1875	class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1876	DeclSetVector &Decls;
1877	SmallVectorImpl<SourceRange> &Ranges;
1878	bool Simple;
1879	public:
1880	typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1881
1882	DeclExtractor(Sema &S, DeclSetVector &Decls,
1883	SmallVectorImpl<SourceRange> &Ranges) :
1884	Inherited(S.Context),
1885	Decls(Decls),
1886	Ranges(Ranges),
1887	Simple(true) {}
1888
1889	bool isSimple() { return Simple; }
1890
1891	// Replaces the method in EvaluatedExprVisitor.
1892	void VisitMemberExpr(MemberExpr* E) {
1893	Simple = false;
1894	}
1895
1896	// Any Stmt not explicitly listed will cause the condition to be marked
1897	// complex.
1898	void VisitStmt(Stmt *S) { Simple = false; }
1899
1900	void VisitBinaryOperator(BinaryOperator *E) {
1901	Visit(E->getLHS());
1902	Visit(E->getRHS());
1903	}
1904
1905	void VisitCastExpr(CastExpr *E) {
1906	Visit(E->getSubExpr());
1907	}
1908
1909	void VisitUnaryOperator(UnaryOperator *E) {
1910	// Skip checking conditionals with derefernces.
1911	if (E->getOpcode() == UO_Deref)
1912	Simple = false;
1913	else
1914	Visit(E->getSubExpr());
1915	}
1916
1917	void VisitConditionalOperator(ConditionalOperator *E) {
1918	Visit(E->getCond());
1919	Visit(E->getTrueExpr());
1920	Visit(E->getFalseExpr());
1921	}
1922
1923	void VisitParenExpr(ParenExpr *E) {
1924	Visit(E->getSubExpr());
1925	}
1926
1927	void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1928	Visit(E->getOpaqueValue()->getSourceExpr());
1929	Visit(E->getFalseExpr());
1930	}
1931
1932	void VisitIntegerLiteral(IntegerLiteral *E) { }
1933	void VisitFloatingLiteral(FloatingLiteral *E) { }
1934	void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1935	void VisitCharacterLiteral(CharacterLiteral *E) { }
1936	void VisitGNUNullExpr(GNUNullExpr *E) { }
1937	void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1938
1939	void VisitDeclRefExpr(DeclRefExpr *E) {
1940	VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl());
1941	if (!VD) {
1942	// Don't allow unhandled Decl types.
1943	Simple = false;
1944	return;
1945	}
1946
1947	Ranges.push_back(Elt: E->getSourceRange());
1948
1949	Decls.insert(X: VD);
1950	}
1951
1952	}; // end class DeclExtractor
1953
1954	// DeclMatcher checks to see if the decls are used in a non-evaluated
1955	// context.
1956	class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1957	DeclSetVector &Decls;
1958	bool FoundDecl;
1959
1960	public:
1961	typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1962
1963	DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1964	Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1965	if (!Statement) return;
1966
1967	Visit(S: Statement);
1968	}
1969
1970	void VisitReturnStmt(ReturnStmt *S) {
1971	FoundDecl = true;
1972	}
1973
1974	void VisitBreakStmt(BreakStmt *S) {
1975	FoundDecl = true;
1976	}
1977
1978	void VisitGotoStmt(GotoStmt *S) {
1979	FoundDecl = true;
1980	}
1981
1982	void VisitCastExpr(CastExpr *E) {
1983	if (E->getCastKind() == CK_LValueToRValue)
1984	CheckLValueToRValueCast(E: E->getSubExpr());
1985	else
1986	Visit(E->getSubExpr());
1987	}
1988
1989	void CheckLValueToRValueCast(Expr *E) {
1990	E = E->IgnoreParenImpCasts();
1991
1992	if (isa<DeclRefExpr>(Val: E)) {
1993	return;
1994	}
1995
1996	if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(Val: E)) {
1997	Visit(CO->getCond());
1998	CheckLValueToRValueCast(E: CO->getTrueExpr());
1999	CheckLValueToRValueCast(E: CO->getFalseExpr());
2000	return;
2001	}
2002
2003	if (BinaryConditionalOperator *BCO =
2004	dyn_cast<BinaryConditionalOperator>(Val: E)) {
2005	CheckLValueToRValueCast(E: BCO->getOpaqueValue()->getSourceExpr());
2006	CheckLValueToRValueCast(E: BCO->getFalseExpr());
2007	return;
2008	}
2009
2010	Visit(E);
2011	}
2012
2013	void VisitDeclRefExpr(DeclRefExpr *E) {
2014	if (VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl()))
2015	if (Decls.count(key: VD))
2016	FoundDecl = true;
2017	}
2018
2019	void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
2020	// Only need to visit the semantics for POE.
2021	// SyntaticForm doesn't really use the Decal.
2022	for (auto *S : POE->semantics()) {
2023	if (auto *OVE = dyn_cast<OpaqueValueExpr>(Val: S))
2024	// Look past the OVE into the expression it binds.
2025	Visit(OVE->getSourceExpr());
2026	else
2027	Visit(S);
2028	}
2029	}
2030
2031	bool FoundDeclInUse() { return FoundDecl; }
2032
2033	}; // end class DeclMatcher
2034
2035	void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
2036	Expr *Third, Stmt *Body) {
2037	// Condition is empty
2038	if (!Second) return;
2039
2040	if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
2041	Second->getBeginLoc()))
2042	return;
2043
2044	PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
2045	DeclSetVector Decls;
2046	SmallVector<SourceRange, 10> Ranges;
2047	DeclExtractor DE(S, Decls, Ranges);
2048	DE.Visit(Second);
2049
2050	// Don't analyze complex conditionals.
2051	if (!DE.isSimple()) return;
2052
2053	// No decls found.
2054	if (Decls.size() == 0) return;
2055
2056	// Don't warn on volatile, static, or global variables.
2057	for (auto *VD : Decls)
2058	if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
2059	return;
2060
2061	if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
2062	DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
2063	DeclMatcher(S, Decls, Body).FoundDeclInUse())
2064	return;
2065
2066	// Load decl names into diagnostic.
2067	if (Decls.size() > 4) {
2068	PDiag << 0;
2069	} else {
2070	PDiag << (unsigned)Decls.size();
2071	for (auto *VD : Decls)
2072	PDiag << VD->getDeclName();
2073	}
2074
2075	for (auto Range : Ranges)
2076	PDiag << Range;
2077
2078	S.Diag(Ranges.begin()->getBegin(), PDiag);
2079	}
2080
2081	// If Statement is an incemement or decrement, return true and sets the
2082	// variables Increment and DRE.
2083	bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
2084	DeclRefExpr *&DRE) {
2085	if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: Statement))
2086	if (!Cleanups->cleanupsHaveSideEffects())
2087	Statement = Cleanups->getSubExpr();
2088
2089	if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Statement)) {
2090	switch (UO->getOpcode()) {
2091	default: return false;
2092	case UO_PostInc:
2093	case UO_PreInc:
2094	Increment = true;
2095	break;
2096	case UO_PostDec:
2097	case UO_PreDec:
2098	Increment = false;
2099	break;
2100	}
2101	DRE = dyn_cast<DeclRefExpr>(Val: UO->getSubExpr());
2102	return DRE;
2103	}
2104
2105	if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Val: Statement)) {
2106	FunctionDecl *FD = Call->getDirectCallee();
2107	if (!FD || !FD->isOverloadedOperator()) return false;
2108	switch (FD->getOverloadedOperator()) {
2109	default: return false;
2110	case OO_PlusPlus:
2111	Increment = true;
2112	break;
2113	case OO_MinusMinus:
2114	Increment = false;
2115	break;
2116	}
2117	DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
2118	return DRE;
2119	}
2120
2121	return false;
2122	}
2123
2124	// A visitor to determine if a continue or break statement is a
2125	// subexpression.
2126	class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
2127	SourceLocation BreakLoc;
2128	SourceLocation ContinueLoc;
2129	bool InSwitch = false;
2130
2131	public:
2132	BreakContinueFinder(Sema &S, const Stmt* Body) :
2133	Inherited(S.Context) {
2134	Visit(S: Body);
2135	}
2136
2137	typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
2138
2139	void VisitContinueStmt(const ContinueStmt* E) {
2140	ContinueLoc = E->getContinueLoc();
2141	}
2142
2143	void VisitBreakStmt(const BreakStmt* E) {
2144	if (!InSwitch)
2145	BreakLoc = E->getBreakLoc();
2146	}
2147
2148	void VisitSwitchStmt(const SwitchStmt* S) {
2149	if (const Stmt *Init = S->getInit())
2150	Visit(S: Init);
2151	if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
2152	Visit(S: CondVar);
2153	if (const Stmt *Cond = S->getCond())
2154	Visit(S: Cond);
2155
2156	// Don't return break statements from the body of a switch.
2157	InSwitch = true;
2158	if (const Stmt *Body = S->getBody())
2159	Visit(S: Body);
2160	InSwitch = false;
2161	}
2162
2163	void VisitForStmt(const ForStmt *S) {
2164	// Only visit the init statement of a for loop; the body
2165	// has a different break/continue scope.
2166	if (const Stmt *Init = S->getInit())
2167	Visit(S: Init);
2168	}
2169
2170	void VisitWhileStmt(const WhileStmt *) {
2171	// Do nothing; the children of a while loop have a different
2172	// break/continue scope.
2173	}
2174
2175	void VisitDoStmt(const DoStmt *) {
2176	// Do nothing; the children of a while loop have a different
2177	// break/continue scope.
2178	}
2179
2180	void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
2181	// Only visit the initialization of a for loop; the body
2182	// has a different break/continue scope.
2183	if (const Stmt *Init = S->getInit())
2184	Visit(S: Init);
2185	if (const Stmt *Range = S->getRangeStmt())
2186	Visit(S: Range);
2187	if (const Stmt *Begin = S->getBeginStmt())
2188	Visit(S: Begin);
2189	if (const Stmt *End = S->getEndStmt())
2190	Visit(S: End);
2191	}
2192
2193	void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
2194	// Only visit the initialization of a for loop; the body
2195	// has a different break/continue scope.
2196	if (const Stmt *Element = S->getElement())
2197	Visit(S: Element);
2198	if (const Stmt *Collection = S->getCollection())
2199	Visit(S: Collection);
2200	}
2201
2202	bool ContinueFound() { return ContinueLoc.isValid(); }
2203	bool BreakFound() { return BreakLoc.isValid(); }
2204	SourceLocation GetContinueLoc() { return ContinueLoc; }
2205	SourceLocation GetBreakLoc() { return BreakLoc; }
2206
2207	}; // end class BreakContinueFinder
2208
2209	// Emit a warning when a loop increment/decrement appears twice per loop
2210	// iteration. The conditions which trigger this warning are:
2211	// 1) The last statement in the loop body and the third expression in the
2212	// for loop are both increment or both decrement of the same variable
2213	// 2) No continue statements in the loop body.
2214	void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
2215	// Return when there is nothing to check.
2216	if (!Body || !Third) return;
2217
2218	// Get the last statement from the loop body.
2219	CompoundStmt *CS = dyn_cast<CompoundStmt>(Val: Body);
2220	if (!CS || CS->body_empty()) return;
2221	Stmt *LastStmt = CS->body_back();
2222	if (!LastStmt) return;
2223
2224	if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
2225	Third->getBeginLoc()))
2226	return;
2227
2228	bool LoopIncrement, LastIncrement;
2229	DeclRefExpr *LoopDRE, *LastDRE;
2230
2231	if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
2232	if (!ProcessIterationStmt(S, Statement: LastStmt, Increment&: LastIncrement, DRE&: LastDRE)) return;
2233
2234	// Check that the two statements are both increments or both decrements
2235	// on the same variable.
2236	if (LoopIncrement != LastIncrement ||
2237	LoopDRE->getDecl() != LastDRE->getDecl()) return;
2238
2239	if (BreakContinueFinder(S, Body).ContinueFound()) return;
2240
2241	S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
2242	<< LastDRE->getDecl() << LastIncrement;
2243	S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
2244	<< LoopIncrement;
2245	}
2246
2247	} // end namespace
2248
2249
2250	void Sema::CheckBreakContinueBinding(Expr *E) {
2251	if (!E || getLangOpts().CPlusPlus)
2252	return;
2253	BreakContinueFinder BCFinder(*this, E);
2254	Scope *BreakParent = CurScope->getBreakParent();
2255	if (BCFinder.BreakFound() && BreakParent) {
2256	if (BreakParent->getFlags() & Scope::SwitchScope) {
2257	Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
2258	} else {
2259	Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
2260	<< "break";
2261	}
2262	} else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
2263	Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
2264	<< "continue";
2265	}
2266	}
2267
2268	StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
2269	Stmt *First, ConditionResult Second,
2270	FullExprArg third, SourceLocation RParenLoc,
2271	Stmt *Body) {
2272	if (Second.isInvalid())
2273	return StmtError();
2274
2275	if (!getLangOpts().CPlusPlus) {
2276	if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(Val: First)) {
2277	// C99 6.8.5p3: The declaration part of a 'for' statement shall only
2278	// declare identifiers for objects having storage class 'auto' or
2279	// 'register'.
2280	const Decl *NonVarSeen = nullptr;
2281	bool VarDeclSeen = false;
2282	for (auto *DI : DS->decls()) {
2283	if (VarDecl *VD = dyn_cast<VarDecl>(Val: DI)) {
2284	VarDeclSeen = true;
2285	if (VD->isLocalVarDecl() && !VD->hasLocalStorage())
2286	Diag(DI->getLocation(),
2287	getLangOpts().C23
2288	? diag::warn_c17_non_local_variable_decl_in_for
2289	: diag::ext_c23_non_local_variable_decl_in_for);
2290	} else if (!NonVarSeen) {
2291	// Keep track of the first non-variable declaration we saw so that
2292	// we can diagnose if we don't see any variable declarations. This
2293	// covers a case like declaring a typedef, function, or structure
2294	// type rather than a variable.
2295	NonVarSeen = DI;
2296	}
2297	}
2298	// Diagnose if we saw a non-variable declaration but no variable
2299	// declarations.
2300	if (NonVarSeen && !VarDeclSeen)
2301	Diag(NonVarSeen->getLocation(),
2302	getLangOpts().C23 ? diag::warn_c17_non_variable_decl_in_for
2303	: diag::ext_c23_non_variable_decl_in_for);
2304	}
2305	}
2306
2307	CheckBreakContinueBinding(E: Second.get().second);
2308	CheckBreakContinueBinding(E: third.get());
2309
2310	if (!Second.get().first)
2311	CheckForLoopConditionalStatement(S&: *this, Second: Second.get().second, Third: third.get(),
2312	Body);
2313	CheckForRedundantIteration(S&: *this, Third: third.get(), Body);
2314
2315	if (Second.get().second &&
2316	!Diags.isIgnored(diag::warn_comma_operator,
2317	Second.get().second->getExprLoc()))
2318	CommaVisitor(*this).Visit(Second.get().second);
2319
2320	Expr *Third = third.release().getAs<Expr>();
2321	if (isa<NullStmt>(Val: Body))
2322	getCurCompoundScope().setHasEmptyLoopBodies();
2323
2324	return new (Context)
2325	ForStmt(Context, First, Second.get().second, Second.get().first, Third,
2326	Body, ForLoc, LParenLoc, RParenLoc);
2327	}
2328
2329	StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
2330	// Reduce placeholder expressions here. Note that this rejects the
2331	// use of pseudo-object l-values in this position.
2332	ExprResult result = CheckPlaceholderExpr(E);
2333	if (result.isInvalid()) return StmtError();
2334	E = result.get();
2335
2336	ExprResult FullExpr = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
2337	if (FullExpr.isInvalid())
2338	return StmtError();
2339	return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2340	}
2341
2342	/// Finish building a variable declaration for a for-range statement.
2343	/// \return true if an error occurs.
2344	static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
2345	SourceLocation Loc, int DiagID) {
2346	if (Decl->getType()->isUndeducedType()) {
2347	ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(E: Init);
2348	if (!Res.isUsable()) {
2349	Decl->setInvalidDecl();
2350	return true;
2351	}
2352	Init = Res.get();
2353	}
2354
2355	// Deduce the type for the iterator variable now rather than leaving it to
2356	// AddInitializerToDecl, so we can produce a more suitable diagnostic.
2357	QualType InitType;
2358	if (!isa<InitListExpr>(Val: Init) && Init->getType()->isVoidType()) {
2359	SemaRef.Diag(Loc, DiagID) << Init->getType();
2360	} else {
2361	TemplateDeductionInfo Info(Init->getExprLoc());
2362	TemplateDeductionResult Result = SemaRef.DeduceAutoType(
2363	AutoTypeLoc: Decl->getTypeSourceInfo()->getTypeLoc(), Initializer: Init, Result&: InitType, Info);
2364	if (Result != TemplateDeductionResult::Success &&
2365	Result != TemplateDeductionResult::AlreadyDiagnosed)
2366	SemaRef.Diag(Loc, DiagID) << Init->getType();
2367	}
2368
2369	if (InitType.isNull()) {
2370	Decl->setInvalidDecl();
2371	return true;
2372	}
2373	Decl->setType(InitType);
2374
2375	// In ARC, infer lifetime.
2376	// FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
2377	// we're doing the equivalent of fast iteration.
2378	if (SemaRef.getLangOpts().ObjCAutoRefCount &&
2379	SemaRef.ObjC().inferObjCARCLifetime(Decl))
2380	Decl->setInvalidDecl();
2381
2382	SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false);
2383	SemaRef.FinalizeDeclaration(Decl);
2384	SemaRef.CurContext->addHiddenDecl(Decl);
2385	return false;
2386	}
2387
2388	namespace {
2389	// An enum to represent whether something is dealing with a call to begin()
2390	// or a call to end() in a range-based for loop.
2391	enum BeginEndFunction {
2392	BEF_begin,
2393	BEF_end
2394	};
2395
2396	/// Produce a note indicating which begin/end function was implicitly called
2397	/// by a C++11 for-range statement. This is often not obvious from the code,
2398	/// nor from the diagnostics produced when analysing the implicit expressions
2399	/// required in a for-range statement.
2400	void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2401	BeginEndFunction BEF) {
2402	CallExpr *CE = dyn_cast<CallExpr>(Val: E);
2403	if (!CE)
2404	return;
2405	FunctionDecl *D = dyn_cast<FunctionDecl>(Val: CE->getCalleeDecl());
2406	if (!D)
2407	return;
2408	SourceLocation Loc = D->getLocation();
2409
2410	std::string Description;
2411	bool IsTemplate = false;
2412	if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2413	Description = SemaRef.getTemplateArgumentBindingsText(
2414	FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
2415	IsTemplate = true;
2416	}
2417
2418	SemaRef.Diag(Loc, diag::note_for_range_begin_end)
2419	<< BEF << IsTemplate << Description << E->getType();
2420	}
2421
2422	/// Build a variable declaration for a for-range statement.
2423	VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
2424	QualType Type, StringRef Name) {
2425	DeclContext *DC = SemaRef.CurContext;
2426	IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
2427	TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(T: Type, Loc);
2428	VarDecl *Decl = VarDecl::Create(C&: SemaRef.Context, DC, StartLoc: Loc, IdLoc: Loc, Id: II, T: Type,
2429	TInfo, S: SC_None);
2430	Decl->setImplicit();
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(InitStmt->getBeginLoc(), 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(DS->getBeginLoc(), 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(*this, RangeVar, Range, RangeLoc,
2492	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(BeginRange->getBeginLoc(), 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, BeginVar, BeginExpr->get(), ColonLoc,
2566	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(EndRange->getBeginLoc(), diag::note_in_for_range)
2582	<< ColonLoc << BEF_end << EndRange->getType();
2583	return RangeStatus;
2584	}
2585	if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2586	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(BeginMemberLookup, D);
2600	if (BeginMemberLookup.isAmbiguous())
2601	return Sema::FRS_DiagnosticIssued;
2602
2603	SemaRef.LookupQualifiedName(EndMemberLookup, 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	PartialDiagnosticAt(BeginRange->getBeginLoc(),
2629	SemaRef.PDiag(diag::err_for_range_invalid)
2630	<< BeginRange->getType() << BEFFound),
2631	SemaRef, OCD_AllCandidates, BeginRange);
2632	[[fallthrough]];
2633
2634	case Sema::FRS_DiagnosticIssued:
2635	for (NamedDecl *D : OldFound) {
2636	SemaRef.Diag(D->getLocation(),
2637	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(RangeLoc, diag::err_for_range_dereference)
2693	<< Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
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(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(RangeVar, RangeVarNonRefType,
2747	VK_LValue, ColonLoc);
2748	if (BeginRangeRef.isInvalid())
2749	return StmtError();
2750
2751	ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2752	VK_LValue, 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(RangeLoc, RangeType,
2763	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(RangeVar, 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(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2798	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(*this, EndVar, EndExpr.get(), ColonLoc,
2871	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(Range->getBeginLoc(), diag::err_range_on_array_parameter)
2894	<< RangeLoc << PVD << ArrayTy << PointerTy;
2895	Diag(PVD->getLocation(), 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	PartialDiagnosticAt(Range->getBeginLoc(),
2917	PDiag(diag::err_for_range_invalid)
2918	<< RangeLoc << Range->getType()
2919	<< BEFFailure),
2920	*this, OCD_AllCandidates, 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(RangeLoc, 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(BeginVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
2944	EndDeclStmt =
2945	ActOnDeclStmt(dg: ConvertDeclToDeclGroup(EndVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
2946
2947	const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
2948	ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
2949	VK_LValue, ColonLoc);
2950	if (BeginRef.isInvalid())
2951	return StmtError();
2952
2953	ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
2954	VK_LValue, 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(RangeLoc, 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(BeginVar, BeginRefNonRefType,
2977	VK_LValue, 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(RangeLoc, 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(BeginVar, BeginRefNonRefType,
2998	VK_LValue, 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(RangeLoc, 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(LoopVar, 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>(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(VD->getLocation(),
3097	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(VD->getBeginLoc(), diag::note_use_type_or_non_reference)
3104	<< NonReferenceType << NewReferenceType << VD->getSourceRange()
3105	<< FixItHint::CreateRemoval(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(VD->getLocation(), diag::warn_for_range_ref_binds_ret_temp)
3112	<< VD << RangeInitType;
3113	QualType NonReferenceType = VariableType.getNonReferenceType();
3114	NonReferenceType.removeLocalConst();
3115	SemaRef.Diag(VD->getBeginLoc(), diag::note_use_non_reference_type)
3116	<< NonReferenceType << VD->getSourceRange()
3117	<< FixItHint::CreateRemoval(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(VD->getLocation(), diag::warn_for_range_copy)
3163	<< VD << VariableType;
3164	SemaRef.Diag(VD->getBeginLoc(), diag::note_use_reference_type)
3165	<< SemaRef.Context.getLValueReferenceType(VariableType)
3166	<< VD->getSourceRange()
3167	<< FixItHint::CreateInsertion(VD->getLocation(), "&");
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	diag::warn_for_range_const_ref_binds_temp_built_from_ref, Loc) &&
3186	SemaRef.Diags.isIgnored(diag::warn_for_range_ref_binds_ret_temp, Loc) &&
3187	SemaRef.Diags.isIgnored(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(ForStmt->getRParenLoc(), B,
3226	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(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(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, 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(ContinueLoc, 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(ContinueLoc, 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(ContinueLoc, 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(BreakLoc, diag::err_break_not_in_loop_or_switch));
3321	}
3322	if (S->isOpenMPLoopScope())
3323	return StmtError(Diag(BreakLoc, 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(BreakLoc, 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(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(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: 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(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(ReturnLoc, 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(ReturnLoc, 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(ReturnLoc, 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(ReturnLoc, 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(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
3639	else {
3640	Diag(ReturnLoc, diag::err_return_block_has_expr);
3641	RetValExp = nullptr;
3642	}
3643	}
3644	} else if (!RetValExp) {
3645	return StmtError(Diag(ReturnLoc, 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>(TmpD))
3722	if (T->getAccess() != AS_private || R->hasFriends())
3723	S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/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(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(RetExpr->getExprLoc(),
3748	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(ReturnLoc, 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(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3811	<< Info.SecondArg << Info.FirstArg << true /*IsLambda*/;
3812	else
3813	Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3814	<< (AT->isDecltypeAuto() ? 1 : 0) << Info.SecondArg
3815	<< Info.FirstArg;
3816	return true;
3817	}
3818	default:
3819	Diag(RetExpr->getExprLoc(), 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(RetExpr->getType());
3829
3830	// CUDA: Kernel function must have 'void' return type.
3831	if (getLangOpts().CUDA && FD->hasAttr<CUDAGlobalAttr>() &&
3832	!Deduced->isVoidType()) {
3833	Diag(FD->getLocation(), 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	// Correct typos, in case the containing function returns 'auto' and
3849	// RetValExp should determine the deduced type.
3850	ExprResult RetVal = CorrectDelayedTyposInExpr(
3851	E: RetValExp, InitDecl: nullptr, /*RecoverUncorrectedTypos=*/true);
3852	if (RetVal.isInvalid())
3853	return StmtError();
3854
3855	if (getCurScope()->isInOpenACCComputeConstructScope())
3856	return StmtError(
3857	Diag(ReturnLoc, diag::err_acc_branch_in_out_compute_construct)
3858	<< /*return*/ 1 << /*out of */ 0);
3859
3860	// using plain return in a coroutine is not allowed.
3861	FunctionScopeInfo *FSI = getCurFunction();
3862	if (FSI->FirstReturnLoc.isInvalid() && FSI->isCoroutine()) {
3863	assert(FSI->FirstCoroutineStmtLoc.isValid() &&
3864	"first coroutine location not set");
3865	Diag(ReturnLoc, diag::err_return_in_coroutine);
3866	Diag(FSI->FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
3867	<< FSI->getFirstCoroutineStmtKeyword();
3868	}
3869
3870	CheckInvalidBuiltinCountedByRef(E: RetVal.get(),
3871	K: BuiltinCountedByRefKind::ReturnArg);
3872
3873	StmtResult R =
3874	BuildReturnStmt(ReturnLoc, RetValExp: RetVal.get(), /*AllowRecovery=*/true);
3875	if (R.isInvalid() || ExprEvalContexts.back().isDiscardedStatementContext())
3876	return R;
3877
3878	VarDecl *VD =
3879	const_cast<VarDecl *>(cast<ReturnStmt>(Val: R.get())->getNRVOCandidate());
3880
3881	CurScope->updateNRVOCandidate(VD);
3882
3883	CheckJumpOutOfSEHFinally(S&: *this, Loc: ReturnLoc, DestScope: *CurScope->getFnParent());
3884
3885	return R;
3886	}
3887
3888	static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
3889	const Expr *E) {
3890	if (!E || !S.getLangOpts().CPlusPlus23 || !S.getLangOpts().MSVCCompat)
3891	return false;
3892	const Decl *D = E->getReferencedDeclOfCallee();
3893	if (!D || !S.SourceMgr.isInSystemHeader(Loc: D->getLocation()))
3894	return false;
3895	for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
3896	if (DC->isStdNamespace())
3897	return true;
3898	}
3899	return false;
3900	}
3901
3902	StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3903	bool AllowRecovery) {
3904	// Check for unexpanded parameter packs.
3905	if (RetValExp && DiagnoseUnexpandedParameterPack(E: RetValExp))
3906	return StmtError();
3907
3908	// HACK: We suppress simpler implicit move here in msvc compatibility mode
3909	// just as a temporary work around, as the MSVC STL has issues with
3910	// this change.
3911	bool SupressSimplerImplicitMoves =
3912	CheckSimplerImplicitMovesMSVCWorkaround(S: *this, E: RetValExp);
3913	NamedReturnInfo NRInfo = getNamedReturnInfo(
3914	E&: RetValExp, Mode: SupressSimplerImplicitMoves ? SimplerImplicitMoveMode::ForceOff
3915	: SimplerImplicitMoveMode::Normal);
3916
3917	if (isa<CapturingScopeInfo>(Val: getCurFunction()))
3918	return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
3919	SupressSimplerImplicitMoves);
3920
3921	QualType FnRetType;
3922	QualType RelatedRetType;
3923	const AttrVec *Attrs = nullptr;
3924	bool isObjCMethod = false;
3925
3926	if (const FunctionDecl *FD = getCurFunctionDecl()) {
3927	FnRetType = FD->getReturnType();
3928	if (FD->hasAttrs())
3929	Attrs = &FD->getAttrs();
3930	if (FD->isNoReturn() && !getCurFunction()->isCoroutine())
3931	Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) << FD;
3932	if (FD->isMain() && RetValExp)
3933	if (isa<CXXBoolLiteralExpr>(RetValExp))
3934	Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
3935	<< RetValExp->getSourceRange();
3936	if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
3937	if (const auto *RT = dyn_cast<RecordType>(Val: FnRetType.getCanonicalType())) {
3938	if (RT->getDecl()->isOrContainsUnion())
3939	Diag(RetValExp->getBeginLoc(), diag::warn_cmse_nonsecure_union) << 1;
3940	}
3941	}
3942	} else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
3943	FnRetType = MD->getReturnType();
3944	isObjCMethod = true;
3945	if (MD->hasAttrs())
3946	Attrs = &MD->getAttrs();
3947	if (MD->hasRelatedResultType() && MD->getClassInterface()) {
3948	// In the implementation of a method with a related return type, the
3949	// type used to type-check the validity of return statements within the
3950	// method body is a pointer to the type of the class being implemented.
3951	RelatedRetType = Context.getObjCInterfaceType(Decl: MD->getClassInterface());
3952	RelatedRetType = Context.getObjCObjectPointerType(OIT: RelatedRetType);
3953	}
3954	} else // If we don't have a function/method context, bail.
3955	return StmtError();
3956
3957	if (RetValExp) {
3958	const auto *ATy = dyn_cast<ArrayType>(Val: RetValExp->getType());
3959	if (ATy && ATy->getElementType().isWebAssemblyReferenceType()) {
3960	Diag(ReturnLoc, diag::err_wasm_table_art) << 1;
3961	return StmtError();
3962	}
3963	}
3964
3965	// C++1z: discarded return statements are not considered when deducing a
3966	// return type.
3967	if (ExprEvalContexts.back().isDiscardedStatementContext() &&
3968	FnRetType->getContainedAutoType()) {
3969	if (RetValExp) {
3970	ExprResult ER =
3971	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3972	if (ER.isInvalid())
3973	return StmtError();
3974	RetValExp = ER.get();
3975	}
3976	return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
3977	/* NRVOCandidate=*/nullptr);
3978	}
3979
3980	// FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
3981	// deduction.
3982	if (getLangOpts().CPlusPlus14) {
3983	if (AutoType *AT = FnRetType->getContainedAutoType()) {
3984	FunctionDecl *FD = cast<FunctionDecl>(Val: CurContext);
3985	// If we've already decided this function is invalid, e.g. because
3986	// we saw a `return` whose expression had an error, don't keep
3987	// trying to deduce its return type.
3988	// (Some return values may be needlessly wrapped in RecoveryExpr).
3989	if (FD->isInvalidDecl() ||
3990	DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
3991	FD->setInvalidDecl();
3992	if (!AllowRecovery)
3993	return StmtError();
3994	// The deduction failure is diagnosed and marked, try to recover.
3995	if (RetValExp) {
3996	// Wrap return value with a recovery expression of the previous type.
3997	// If no deduction yet, use DependentTy.
3998	auto Recovery = CreateRecoveryExpr(
3999	Begin: RetValExp->getBeginLoc(), End: RetValExp->getEndLoc(), SubExprs: RetValExp,
4000	T: AT->isDeduced() ? FnRetType : QualType());
4001	if (Recovery.isInvalid())
4002	return StmtError();
4003	RetValExp = Recovery.get();
4004	} else {
4005	// Nothing to do: a ReturnStmt with no value is fine recovery.
4006	}
4007	} else {
4008	FnRetType = FD->getReturnType();
4009	}
4010	}
4011	}
4012	const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
4013
4014	bool HasDependentReturnType = FnRetType->isDependentType();
4015
4016	ReturnStmt *Result = nullptr;
4017	if (FnRetType->isVoidType()) {
4018	if (RetValExp) {
4019	if (auto *ILE = dyn_cast<InitListExpr>(Val: RetValExp)) {
4020	// We simply never allow init lists as the return value of void
4021	// functions. This is compatible because this was never allowed before,
4022	// so there's no legacy code to deal with.
4023	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4024	int FunctionKind = 0;
4025	if (isa<ObjCMethodDecl>(Val: CurDecl))
4026	FunctionKind = 1;
4027	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4028	FunctionKind = 2;
4029	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4030	FunctionKind = 3;
4031
4032	Diag(ReturnLoc, diag::err_return_init_list)
4033	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4034
4035	// Preserve the initializers in the AST.
4036	RetValExp = AllowRecovery
4037	? CreateRecoveryExpr(Begin: ILE->getLBraceLoc(),
4038	End: ILE->getRBraceLoc(), SubExprs: ILE->inits())
4039	.get()
4040	: nullptr;
4041	} else if (!RetValExp->isTypeDependent()) {
4042	// C99 6.8.6.4p1 (ext_ since GCC warns)
4043	unsigned D = diag::ext_return_has_expr;
4044	if (RetValExp->getType()->isVoidType()) {
4045	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4046	if (isa<CXXConstructorDecl>(CurDecl) ||
4047	isa<CXXDestructorDecl>(CurDecl))
4048	D = diag::err_ctor_dtor_returns_void;
4049	else
4050	D = diag::ext_return_has_void_expr;
4051	}
4052	else {
4053	ExprResult Result = RetValExp;
4054	Result = IgnoredValueConversions(E: Result.get());
4055	if (Result.isInvalid())
4056	return StmtError();
4057	RetValExp = Result.get();
4058	RetValExp = ImpCastExprToType(E: RetValExp,
4059	Type: Context.VoidTy, CK: CK_ToVoid).get();
4060	}
4061	// return of void in constructor/destructor is illegal in C++.
4062	if (D == diag::err_ctor_dtor_returns_void) {
4063	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4064	Diag(ReturnLoc, D) << CurDecl << isa<CXXDestructorDecl>(Val: CurDecl)
4065	<< RetValExp->getSourceRange();
4066	}
4067	// return (some void expression); is legal in C++ and C2y.
4068	else if (D != diag::ext_return_has_void_expr ||
4069	(!getLangOpts().CPlusPlus && !getLangOpts().C2y)) {
4070	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4071
4072	int FunctionKind = 0;
4073	if (isa<ObjCMethodDecl>(Val: CurDecl))
4074	FunctionKind = 1;
4075	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4076	FunctionKind = 2;
4077	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4078	FunctionKind = 3;
4079
4080	Diag(ReturnLoc, D)
4081	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4082	}
4083	}
4084
4085	if (RetValExp) {
4086	ExprResult ER =
4087	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4088	if (ER.isInvalid())
4089	return StmtError();
4090	RetValExp = ER.get();
4091	}
4092	}
4093
4094	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4095	/* NRVOCandidate=*/nullptr);
4096	} else if (!RetValExp && !HasDependentReturnType) {
4097	FunctionDecl *FD = getCurFunctionDecl();
4098
4099	if ((FD && FD->isInvalidDecl()) || FnRetType->containsErrors()) {
4100	// The intended return type might have been "void", so don't warn.
4101	} else if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
4102	// C++11 [stmt.return]p2
4103	Diag(ReturnLoc, diag::err_constexpr_return_missing_expr)
4104	<< FD << FD->isConsteval();
4105	FD->setInvalidDecl();
4106	} else {
4107	// C99 6.8.6.4p1 (ext_ since GCC warns)
4108	// C90 6.6.6.4p4
4109	unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
4110	: diag::warn_return_missing_expr;
4111	// Note that at this point one of getCurFunctionDecl() or
4112	// getCurMethodDecl() must be non-null (see above).
4113	assert((getCurFunctionDecl() || getCurMethodDecl()) &&
4114	"Not in a FunctionDecl or ObjCMethodDecl?");
4115	bool IsMethod = FD == nullptr;
4116	const NamedDecl *ND =
4117	IsMethod ? cast<NamedDecl>(Val: getCurMethodDecl()) : cast<NamedDecl>(Val: FD);
4118	Diag(ReturnLoc, DiagID) << ND << IsMethod;
4119	}
4120
4121	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, /* RetExpr=*/E: nullptr,
4122	/* NRVOCandidate=*/nullptr);
4123	} else {
4124	assert(RetValExp || HasDependentReturnType);
4125	QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
4126
4127	// C99 6.8.6.4p3(136): The return statement is not an assignment. The
4128	// overlap restriction of subclause 6.5.16.1 does not apply to the case of
4129	// function return.
4130
4131	// In C++ the return statement is handled via a copy initialization,
4132	// the C version of which boils down to CheckSingleAssignmentConstraints.
4133	if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
4134	// we have a non-void function with an expression, continue checking
4135	InitializedEntity Entity =
4136	InitializedEntity::InitializeResult(ReturnLoc, Type: RetType);
4137	ExprResult Res = PerformMoveOrCopyInitialization(
4138	Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
4139	if (Res.isInvalid() && AllowRecovery)
4140	Res = CreateRecoveryExpr(Begin: RetValExp->getBeginLoc(),
4141	End: RetValExp->getEndLoc(), SubExprs: RetValExp, T: RetType);
4142	if (Res.isInvalid()) {
4143	// FIXME: Clean up temporaries here anyway?
4144	return StmtError();
4145	}
4146	RetValExp = Res.getAs<Expr>();
4147
4148	// If we have a related result type, we need to implicitly
4149	// convert back to the formal result type. We can't pretend to
4150	// initialize the result again --- we might end double-retaining
4151	// --- so instead we initialize a notional temporary.
4152	if (!RelatedRetType.isNull()) {
4153	Entity = InitializedEntity::InitializeRelatedResult(MD: getCurMethodDecl(),
4154	Type: FnRetType);
4155	Res = PerformCopyInitialization(Entity, EqualLoc: ReturnLoc, Init: RetValExp);
4156	if (Res.isInvalid()) {
4157	// FIXME: Clean up temporaries here anyway?
4158	return StmtError();
4159	}
4160	RetValExp = Res.getAs<Expr>();
4161	}
4162
4163	CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc, isObjCMethod, Attrs,
4164	FD: getCurFunctionDecl());
4165	}
4166
4167	if (RetValExp) {
4168	ExprResult ER =
4169	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4170	if (ER.isInvalid())
4171	return StmtError();
4172	RetValExp = ER.get();
4173	}
4174	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
4175	}
4176
4177	// If we need to check for the named return value optimization, save the
4178	// return statement in our scope for later processing.
4179	if (Result->getNRVOCandidate())
4180	FunctionScopes.back()->Returns.push_back(Elt: Result);
4181
4182	if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
4183	FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
4184
4185	return Result;
4186	}
4187
4188	StmtResult
4189	Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
4190	Stmt *HandlerBlock) {
4191	// There's nothing to test that ActOnExceptionDecl didn't already test.
4192	return new (Context)
4193	CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(Val: ExDecl), HandlerBlock);
4194	}
4195
4196	namespace {
4197	class CatchHandlerType {
4198	QualType QT;
4199	LLVM_PREFERRED_TYPE(bool)
4200	unsigned IsPointer : 1;
4201
4202	// This is a special constructor to be used only with DenseMapInfo's
4203	// getEmptyKey() and getTombstoneKey() functions.
4204	friend struct llvm::DenseMapInfo<CatchHandlerType>;
4205	enum Unique { ForDenseMap };
4206	CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
4207
4208	public:
4209	/// Used when creating a CatchHandlerType from a handler type; will determine
4210	/// whether the type is a pointer or reference and will strip off the top
4211	/// level pointer and cv-qualifiers.
4212	CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
4213	if (QT->isPointerType())
4214	IsPointer = true;
4215
4216	QT = QT.getUnqualifiedType();
4217	if (IsPointer || QT->isReferenceType())
4218	QT = QT->getPointeeType();
4219	}
4220
4221	/// Used when creating a CatchHandlerType from a base class type; pretends the
4222	/// type passed in had the pointer qualifier, does not need to get an
4223	/// unqualified type.
4224	CatchHandlerType(QualType QT, bool IsPointer)
4225	: QT(QT), IsPointer(IsPointer) {}
4226
4227	QualType underlying() const { return QT; }
4228	bool isPointer() const { return IsPointer; }
4229
4230	friend bool operator==(const CatchHandlerType &LHS,
4231	const CatchHandlerType &RHS) {
4232	// If the pointer qualification does not match, we can return early.
4233	if (LHS.IsPointer != RHS.IsPointer)
4234	return false;
4235	// Otherwise, check the underlying type without cv-qualifiers.
4236	return LHS.QT == RHS.QT;
4237	}
4238	};
4239	} // namespace
4240
4241	namespace llvm {
4242	template <> struct DenseMapInfo<CatchHandlerType> {
4243	static CatchHandlerType getEmptyKey() {
4244	return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
4245	CatchHandlerType::ForDenseMap);
4246	}
4247
4248	static CatchHandlerType getTombstoneKey() {
4249	return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
4250	CatchHandlerType::ForDenseMap);
4251	}
4252
4253	static unsigned getHashValue(const CatchHandlerType &Base) {
4254	return DenseMapInfo<QualType>::getHashValue(Val: Base.underlying());
4255	}
4256
4257	static bool isEqual(const CatchHandlerType &LHS,
4258	const CatchHandlerType &RHS) {
4259	return LHS == RHS;
4260	}
4261	};
4262	}
4263
4264	namespace {
4265	class CatchTypePublicBases {
4266	const llvm::DenseMap<QualType, CXXCatchStmt *> &TypesToCheck;
4267
4268	CXXCatchStmt *FoundHandler;
4269	QualType FoundHandlerType;
4270	QualType TestAgainstType;
4271
4272	public:
4273	CatchTypePublicBases(const llvm::DenseMap<QualType, CXXCatchStmt *> &T,
4274	QualType QT)
4275	: TypesToCheck(T), FoundHandler(nullptr), TestAgainstType(QT) {}
4276
4277	CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
4278	QualType getFoundHandlerType() const { return FoundHandlerType; }
4279
4280	bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
4281	if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
4282	QualType Check = S->getType().getCanonicalType();
4283	const auto &M = TypesToCheck;
4284	auto I = M.find(Val: Check);
4285	if (I != M.end()) {
4286	// We're pretty sure we found what we need to find. However, we still
4287	// need to make sure that we properly compare for pointers and
4288	// references, to handle cases like:
4289	//
4290	// } catch (Base *b) {
4291	// } catch (Derived &d) {
4292	// }
4293	//
4294	// where there is a qualification mismatch that disqualifies this
4295	// handler as a potential problem.
4296	if (I->second->getCaughtType()->isPointerType() ==
4297	TestAgainstType->isPointerType()) {
4298	FoundHandler = I->second;
4299	FoundHandlerType = Check;
4300	return true;
4301	}
4302	}
4303	}
4304	return false;
4305	}
4306	};
4307	}
4308
4309	StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
4310	ArrayRef<Stmt *> Handlers) {
4311	const llvm::Triple &T = Context.getTargetInfo().getTriple();
4312	const bool IsOpenMPGPUTarget =
4313	getLangOpts().OpenMPIsTargetDevice && (T.isNVPTX() || T.isAMDGCN());
4314
4315	DiagnoseExceptionUse(Loc: TryLoc, /* IsTry= */ true);
4316
4317	// In OpenMP target regions, we assume that catch is never reached on GPU
4318	// targets.
4319	if (IsOpenMPGPUTarget)
4320	targetDiag(TryLoc, diag::warn_try_not_valid_on_target) << T.str();
4321
4322	// Exceptions aren't allowed in CUDA device code.
4323	if (getLangOpts().CUDA)
4324	CUDA().DiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
4325	<< "try" << CUDA().CurrentTarget();
4326
4327	if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
4328	Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
4329
4330	sema::FunctionScopeInfo *FSI = getCurFunction();
4331
4332	// C++ try is incompatible with SEH __try.
4333	if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
4334	Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << 0;
4335	Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
4336	}
4337
4338	const unsigned NumHandlers = Handlers.size();
4339	assert(!Handlers.empty() &&
4340	"The parser shouldn't call this if there are no handlers.");
4341
4342	llvm::DenseMap<QualType, CXXCatchStmt *> HandledBaseTypes;
4343	llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
4344	for (unsigned i = 0; i < NumHandlers; ++i) {
4345	CXXCatchStmt *H = cast<CXXCatchStmt>(Val: Handlers[i]);
4346
4347	// Diagnose when the handler is a catch-all handler, but it isn't the last
4348	// handler for the try block. [except.handle]p5. Also, skip exception
4349	// declarations that are invalid, since we can't usefully report on them.
4350	if (!H->getExceptionDecl()) {
4351	if (i < NumHandlers - 1)
4352	return StmtError(Diag(H->getBeginLoc(), diag::err_early_catch_all));
4353	continue;
4354	} else if (H->getExceptionDecl()->isInvalidDecl())
4355	continue;
4356
4357	// Walk the type hierarchy to diagnose when this type has already been
4358	// handled (duplication), or cannot be handled (derivation inversion). We
4359	// ignore top-level cv-qualifiers, per [except.handle]p3
4360	CatchHandlerType HandlerCHT = H->getCaughtType().getCanonicalType();
4361
4362	// We can ignore whether the type is a reference or a pointer; we need the
4363	// underlying declaration type in order to get at the underlying record
4364	// decl, if there is one.
4365	QualType Underlying = HandlerCHT.underlying();
4366	if (auto *RD = Underlying->getAsCXXRecordDecl()) {
4367	if (!RD->hasDefinition())
4368	continue;
4369	// Check that none of the public, unambiguous base classes are in the
4370	// map ([except.handle]p1). Give the base classes the same pointer
4371	// qualification as the original type we are basing off of. This allows
4372	// comparison against the handler type using the same top-level pointer
4373	// as the original type.
4374	CXXBasePaths Paths;
4375	Paths.setOrigin(RD);
4376	CatchTypePublicBases CTPB(HandledBaseTypes,
4377	H->getCaughtType().getCanonicalType());
4378	if (RD->lookupInBases(BaseMatches: CTPB, Paths)) {
4379	const CXXCatchStmt *Problem = CTPB.getFoundHandler();
4380	if (!Paths.isAmbiguous(
4381	BaseType: CanQualType::CreateUnsafe(Other: CTPB.getFoundHandlerType()))) {
4382	Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4383	diag::warn_exception_caught_by_earlier_handler)
4384	<< H->getCaughtType();
4385	Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4386	diag::note_previous_exception_handler)
4387	<< Problem->getCaughtType();
4388	}
4389	}
4390	// Strip the qualifiers here because we're going to be comparing this
4391	// type to the base type specifiers of a class, which are ignored in a
4392	// base specifier per [class.derived.general]p2.
4393	HandledBaseTypes[Underlying.getUnqualifiedType()] = H;
4394	}
4395
4396	// Add the type the list of ones we have handled; diagnose if we've already
4397	// handled it.
4398	auto R = HandledTypes.insert(
4399	std::make_pair(x: H->getCaughtType().getCanonicalType(), y&: H));
4400	if (!R.second) {
4401	const CXXCatchStmt *Problem = R.first->second;
4402	Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4403	diag::warn_exception_caught_by_earlier_handler)
4404	<< H->getCaughtType();
4405	Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4406	diag::note_previous_exception_handler)
4407	<< Problem->getCaughtType();
4408	}
4409	}
4410
4411	FSI->setHasCXXTry(TryLoc);
4412
4413	return CXXTryStmt::Create(C: Context, tryLoc: TryLoc, tryBlock: cast<CompoundStmt>(Val: TryBlock),
4414	handlers: Handlers);
4415	}
4416
4417	void Sema::DiagnoseExceptionUse(SourceLocation Loc, bool IsTry) {
4418	const llvm::Triple &T = Context.getTargetInfo().getTriple();
4419	const bool IsOpenMPGPUTarget =
4420	getLangOpts().OpenMPIsTargetDevice && (T.isNVPTX() || T.isAMDGCN());
4421
4422	// Don't report an error if 'try' is used in system headers or in an OpenMP
4423	// target region compiled for a GPU architecture.
4424	if (IsOpenMPGPUTarget || getLangOpts().CUDA)
4425	// Delay error emission for the OpenMP device code.
4426	return;
4427
4428	if (!getLangOpts().CXXExceptions &&
4429	!getSourceManager().isInSystemHeader(Loc) &&
4430	!CurContext->isDependentContext())
4431	targetDiag(Loc, diag::err_exceptions_disabled) << (IsTry ? "try" : "throw");
4432	}
4433
4434	StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
4435	Stmt *TryBlock, Stmt *Handler) {
4436	assert(TryBlock && Handler);
4437
4438	sema::FunctionScopeInfo *FSI = getCurFunction();
4439
4440	// SEH __try is incompatible with C++ try. Borland appears to support this,
4441	// however.
4442	if (!getLangOpts().Borland) {
4443	if (FSI->FirstCXXOrObjCTryLoc.isValid()) {
4444	Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << FSI->FirstTryType;
4445	Diag(FSI->FirstCXXOrObjCTryLoc, diag::note_conflicting_try_here)
4446	<< (FSI->FirstTryType == sema::FunctionScopeInfo::TryLocIsCXX
4447	? "'try'"
4448	: "'@try'");
4449	}
4450	}
4451
4452	FSI->setHasSEHTry(TryLoc);
4453
4454	// Reject __try in Obj-C methods, blocks, and captured decls, since we don't
4455	// track if they use SEH.
4456	DeclContext *DC = CurContext;
4457	while (DC && !DC->isFunctionOrMethod())
4458	DC = DC->getParent();
4459	FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Val: DC);
4460	if (FD)
4461	FD->setUsesSEHTry(true);
4462	else
4463	Diag(TryLoc, diag::err_seh_try_outside_functions);
4464
4465	// Reject __try on unsupported targets.
4466	if (!Context.getTargetInfo().isSEHTrySupported())
4467	Diag(TryLoc, diag::err_seh_try_unsupported);
4468
4469	return SEHTryStmt::Create(C: Context, isCXXTry: IsCXXTry, TryLoc, TryBlock, Handler);
4470	}
4471
4472	StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
4473	Stmt *Block) {
4474	assert(FilterExpr && Block);
4475	QualType FTy = FilterExpr->getType();
4476	if (!FTy->isIntegerType() && !FTy->isDependentType()) {
4477	return StmtError(
4478	Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral)
4479	<< FTy);
4480	}
4481	return SEHExceptStmt::Create(C: Context, ExceptLoc: Loc, FilterExpr, Block);
4482	}
4483
4484	void Sema::ActOnStartSEHFinallyBlock() {
4485	CurrentSEHFinally.push_back(Elt: CurScope);
4486	}
4487
4488	void Sema::ActOnAbortSEHFinallyBlock() {
4489	CurrentSEHFinally.pop_back();
4490	}
4491
4492	StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
4493	assert(Block);
4494	CurrentSEHFinally.pop_back();
4495	return SEHFinallyStmt::Create(C: Context, FinallyLoc: Loc, Block);
4496	}
4497
4498	StmtResult
4499	Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
4500	Scope *SEHTryParent = CurScope;
4501	while (SEHTryParent && !SEHTryParent->isSEHTryScope())
4502	SEHTryParent = SEHTryParent->getParent();
4503	if (!SEHTryParent)
4504	return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
4505	CheckJumpOutOfSEHFinally(S&: *this, Loc, DestScope: *SEHTryParent);
4506
4507	return new (Context) SEHLeaveStmt(Loc);
4508	}
4509
4510	StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
4511	bool IsIfExists,
4512	NestedNameSpecifierLoc QualifierLoc,
4513	DeclarationNameInfo NameInfo,
4514	Stmt *Nested)
4515	{
4516	return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
4517	QualifierLoc, NameInfo,
4518	cast<CompoundStmt>(Val: Nested));
4519	}
4520
4521
4522	StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4523	bool IsIfExists,
4524	CXXScopeSpec &SS,
4525	UnqualifiedId &Name,
4526	Stmt *Nested) {
4527	return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4528	QualifierLoc: SS.getWithLocInContext(Context),
4529	NameInfo: GetNameFromUnqualifiedId(Name),
4530	Nested);
4531	}
4532
4533	RecordDecl*
4534	Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4535	unsigned NumParams) {
4536	DeclContext *DC = CurContext;
4537	while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4538	DC = DC->getParent();
4539
4540	RecordDecl *RD = nullptr;
4541	if (getLangOpts().CPlusPlus)
4542	RD = CXXRecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4543	/*Id=*/nullptr);
4544	else
4545	RD = RecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4546	/*Id=*/nullptr);
4547
4548	RD->setCapturedRecord();
4549	DC->addDecl(RD);
4550	RD->setImplicit();
4551	RD->startDefinition();
4552
4553	assert(NumParams > 0 && "CapturedStmt requires context parameter");
4554	CD = CapturedDecl::Create(C&: Context, DC: CurContext, NumParams);
4555	DC->addDecl(CD);
4556	return RD;
4557	}
4558
4559	static bool
4560	buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
4561	SmallVectorImpl<CapturedStmt::Capture> &Captures,
4562	SmallVectorImpl<Expr *> &CaptureInits) {
4563	for (const sema::Capture &Cap : RSI->Captures) {
4564	if (Cap.isInvalid())
4565	continue;
4566
4567	// Form the initializer for the capture.
4568	ExprResult Init = S.BuildCaptureInit(Capture: Cap, ImplicitCaptureLoc: Cap.getLocation(),
4569	IsOpenMPMapping: RSI->CapRegionKind == CR_OpenMP);
4570
4571	// FIXME: Bail out now if the capture is not used and the initializer has
4572	// no side-effects.
4573
4574	// Create a field for this capture.
4575	FieldDecl *Field = S.BuildCaptureField(RD: RSI->TheRecordDecl, Capture: Cap);
4576
4577	// Add the capture to our list of captures.
4578	if (Cap.isThisCapture()) {
4579	Captures.push_back(Elt: CapturedStmt::Capture(Cap.getLocation(),
4580	CapturedStmt::VCK_This));
4581	} else if (Cap.isVLATypeCapture()) {
4582	Captures.push_back(
4583	Elt: CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
4584	} else {
4585	assert(Cap.isVariableCapture() && "unknown kind of capture");
4586
4587	if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
4588	S.OpenMP().setOpenMPCaptureKind(FD: Field, D: Cap.getVariable(),
4589	Level: RSI->OpenMPLevel);
4590
4591	Captures.push_back(Elt: CapturedStmt::Capture(
4592	Cap.getLocation(),
4593	Cap.isReferenceCapture() ? CapturedStmt::VCK_ByRef
4594	: CapturedStmt::VCK_ByCopy,
4595	cast<VarDecl>(Val: Cap.getVariable())));
4596	}
4597	CaptureInits.push_back(Elt: Init.get());
4598	}
4599	return false;
4600	}
4601
4602	static std::optional<int>
4603	isOpenMPCapturedRegionInArmSMEFunction(Sema const &S, CapturedRegionKind Kind) {
4604	if (!S.getLangOpts().OpenMP || Kind != CR_OpenMP)
4605	return {};
4606	if (const FunctionDecl *FD = S.getCurFunctionDecl(/*AllowLambda=*/true)) {
4607	if (IsArmStreamingFunction(FD, /*IncludeLocallyStreaming=*/true))
4608	return /* in streaming functions */ 0;
4609	if (hasArmZAState(FD))
4610	return /* in functions with ZA state */ 1;
4611	if (hasArmZT0State(FD))
4612	return /* in fuctions with ZT0 state */ 2;
4613	}
4614	return {};
4615	}
4616
4617	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4618	CapturedRegionKind Kind,
4619	unsigned NumParams) {
4620	if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(*this, Kind))
4621	Diag(Loc, diag::err_sme_openmp_captured_region) << *ErrorIndex;
4622
4623	CapturedDecl *CD = nullptr;
4624	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4625
4626	// Build the context parameter
4627	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4628	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4629	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD));
4630	auto *Param =
4631	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4632	ParamKind: ImplicitParamKind::CapturedContext);
4633	DC->addDecl(D: Param);
4634
4635	CD->setContextParam(i: 0, P: Param);
4636
4637	// Enter the capturing scope for this captured region.
4638	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind);
4639
4640	if (CurScope)
4641	PushDeclContext(CurScope, CD);
4642	else
4643	CurContext = CD;
4644
4645	PushExpressionEvaluationContext(
4646	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4647	ExprEvalContexts.back().InImmediateEscalatingFunctionContext = false;
4648	}
4649
4650	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4651	CapturedRegionKind Kind,
4652	ArrayRef<CapturedParamNameType> Params,
4653	unsigned OpenMPCaptureLevel) {
4654	if (auto ErrorIndex = isOpenMPCapturedRegionInArmSMEFunction(*this, Kind))
4655	Diag(Loc, diag::err_sme_openmp_captured_region) << *ErrorIndex;
4656
4657	CapturedDecl *CD = nullptr;
4658	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams: Params.size());
4659
4660	// Build the context parameter
4661	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4662	bool ContextIsFound = false;
4663	unsigned ParamNum = 0;
4664	for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4665	E = Params.end();
4666	I != E; ++I, ++ParamNum) {
4667	if (I->second.isNull()) {
4668	assert(!ContextIsFound &&
4669	"null type has been found already for '__context' parameter");
4670	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4671	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD))
4672	.withConst()
4673	.withRestrict();
4674	auto *Param =
4675	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4676	ParamKind: ImplicitParamKind::CapturedContext);
4677	DC->addDecl(D: Param);
4678	CD->setContextParam(i: ParamNum, P: Param);
4679	ContextIsFound = true;
4680	} else {
4681	IdentifierInfo *ParamName = &Context.Idents.get(Name: I->first);
4682	auto *Param =
4683	ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
4684	ImplicitParamKind::CapturedContext);
4685	DC->addDecl(D: Param);
4686	CD->setParam(i: ParamNum, P: Param);
4687	}
4688	}
4689	assert(ContextIsFound && "no null type for '__context' parameter");
4690	if (!ContextIsFound) {
4691	// Add __context implicitly if it is not specified.
4692	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4693	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD));
4694	auto *Param =
4695	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4696	ParamKind: ImplicitParamKind::CapturedContext);
4697	DC->addDecl(D: Param);
4698	CD->setContextParam(i: ParamNum, P: Param);
4699	}
4700	// Enter the capturing scope for this captured region.
4701	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind, OpenMPCaptureLevel);
4702
4703	if (CurScope)
4704	PushDeclContext(CurScope, CD);
4705	else
4706	CurContext = CD;
4707
4708	PushExpressionEvaluationContext(
4709	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4710	}
4711
4712	void Sema::ActOnCapturedRegionError() {
4713	DiscardCleanupsInEvaluationContext();
4714	PopExpressionEvaluationContext();
4715	PopDeclContext();
4716	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4717	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4718
4719	RecordDecl *Record = RSI->TheRecordDecl;
4720	Record->setInvalidDecl();
4721
4722	SmallVector<Decl*, 4> Fields(Record->fields());
4723	ActOnFields(/*Scope=*/S: nullptr, RecLoc: Record->getLocation(), TagDecl: Record, Fields,
4724	LBrac: SourceLocation(), RBrac: SourceLocation(), AttrList: ParsedAttributesView());
4725	}
4726
4727	StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4728	// Leave the captured scope before we start creating captures in the
4729	// enclosing scope.
4730	DiscardCleanupsInEvaluationContext();
4731	PopExpressionEvaluationContext();
4732	PopDeclContext();
4733	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4734	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4735
4736	SmallVector<CapturedStmt::Capture, 4> Captures;
4737	SmallVector<Expr *, 4> CaptureInits;
4738	if (buildCapturedStmtCaptureList(S&: *this, RSI, Captures, CaptureInits))
4739	return StmtError();
4740
4741	CapturedDecl *CD = RSI->TheCapturedDecl;
4742	RecordDecl *RD = RSI->TheRecordDecl;
4743
4744	CapturedStmt *Res = CapturedStmt::Create(
4745	Context: getASTContext(), S, Kind: static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4746	Captures, CaptureInits, CD, RD);
4747
4748	CD->setBody(Res->getCapturedStmt());
4749	RD->completeDefinition();
4750
4751	return Res;
4752	}
4753