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 "clang/AST/ASTContext.h"
14	#include "clang/AST/ASTDiagnostic.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/EvaluatedExprVisitor.h"
20	#include "clang/AST/ExprCXX.h"
21	#include "clang/AST/ExprObjC.h"
22	#include "clang/AST/IgnoreExpr.h"
23	#include "clang/AST/RecursiveASTVisitor.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/SemaInternal.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/STLForwardCompat.h"
43	#include "llvm/ADT/SmallPtrSet.h"
44	#include "llvm/ADT/SmallString.h"
45	#include "llvm/ADT/SmallVector.h"
46	#include "llvm/ADT/StringExtras.h"
47
48	using namespace clang;
49	using namespace sema;
50
51	StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
52	if (FE.isInvalid())
53	return StmtError();
54
55	FE = ActOnFinishFullExpr(Expr: FE.get(), CC: FE.get()->getExprLoc(), DiscardedValue);
56	if (FE.isInvalid())
57	return StmtError();
58
59	// C99 6.8.3p2: The expression in an expression statement is evaluated as a
60	// void expression for its side effects. Conversion to void allows any
61	// operand, even incomplete types.
62
63	// Same thing in for stmt first clause (when expr) and third clause.
64	return StmtResult(FE.getAs<Stmt>());
65	}
66
67
68	StmtResult Sema::ActOnExprStmtError() {
69	DiscardCleanupsInEvaluationContext();
70	return StmtError();
71	}
72
73	StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc,
74	bool HasLeadingEmptyMacro) {
75	return new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro);
76	}
77
78	StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc,
79	SourceLocation EndLoc) {
80	DeclGroupRef DG = dg.get();
81
82	// If we have an invalid decl, just return an error.
83	if (DG.isNull()) return StmtError();
84
85	return new (Context) DeclStmt(DG, StartLoc, EndLoc);
86	}
87
88	void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) {
89	DeclGroupRef DG = dg.get();
90
91	// If we don't have a declaration, or we have an invalid declaration,
92	// just return.
93	if (DG.isNull() || !DG.isSingleDecl())
94	return;
95
96	Decl *decl = DG.getSingleDecl();
97	if (!decl || decl->isInvalidDecl())
98	return;
99
100	// Only variable declarations are permitted.
101	VarDecl *var = dyn_cast<VarDecl>(Val: decl);
102	if (!var) {
103	Diag(decl->getLocation(), diag::err_non_variable_decl_in_for);
104	decl->setInvalidDecl();
105	return;
106	}
107
108	// foreach variables are never actually initialized in the way that
109	// the parser came up with.
110	var->setInit(nullptr);
111
112	// In ARC, we don't need to retain the iteration variable of a fast
113	// enumeration loop. Rather than actually trying to catch that
114	// during declaration processing, we remove the consequences here.
115	if (getLangOpts().ObjCAutoRefCount) {
116	QualType type = var->getType();
117
118	// Only do this if we inferred the lifetime. Inferred lifetime
119	// will show up as a local qualifier because explicit lifetime
120	// should have shown up as an AttributedType instead.
121	if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) {
122	// Add 'const' and mark the variable as pseudo-strong.
123	var->setType(type.withConst());
124	var->setARCPseudoStrong(true);
125	}
126	}
127	}
128
129	/// Diagnose unused comparisons, both builtin and overloaded operators.
130	/// For '==' and '!=', suggest fixits for '=' or '|='.
131	///
132	/// Adding a cast to void (or other expression wrappers) will prevent the
133	/// warning from firing.
134	static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) {
135	SourceLocation Loc;
136	bool CanAssign;
137	enum { Equality, Inequality, Relational, ThreeWay } Kind;
138
139	if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(Val: E)) {
140	if (!Op->isComparisonOp())
141	return false;
142
143	if (Op->getOpcode() == BO_EQ)
144	Kind = Equality;
145	else if (Op->getOpcode() == BO_NE)
146	Kind = Inequality;
147	else if (Op->getOpcode() == BO_Cmp)
148	Kind = ThreeWay;
149	else {
150	assert(Op->isRelationalOp());
151	Kind = Relational;
152	}
153	Loc = Op->getOperatorLoc();
154	CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue();
155	} else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(Val: E)) {
156	switch (Op->getOperator()) {
157	case OO_EqualEqual:
158	Kind = Equality;
159	break;
160	case OO_ExclaimEqual:
161	Kind = Inequality;
162	break;
163	case OO_Less:
164	case OO_Greater:
165	case OO_GreaterEqual:
166	case OO_LessEqual:
167	Kind = Relational;
168	break;
169	case OO_Spaceship:
170	Kind = ThreeWay;
171	break;
172	default:
173	return false;
174	}
175
176	Loc = Op->getOperatorLoc();
177	CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue();
178	} else {
179	// Not a typo-prone comparison.
180	return false;
181	}
182
183	// Suppress warnings when the operator, suspicious as it may be, comes from
184	// a macro expansion.
185	if (S.SourceMgr.isMacroBodyExpansion(Loc))
186	return false;
187
188	S.Diag(Loc, diag::warn_unused_comparison)
189	<< (unsigned)Kind << E->getSourceRange();
190
191	// If the LHS is a plausible entity to assign to, provide a fixit hint to
192	// correct common typos.
193	if (CanAssign) {
194	if (Kind == Inequality)
195	S.Diag(Loc, diag::note_inequality_comparison_to_or_assign)
196	<< FixItHint::CreateReplacement(Loc, "|=");
197	else if (Kind == Equality)
198	S.Diag(Loc, diag::note_equality_comparison_to_assign)
199	<< FixItHint::CreateReplacement(Loc, "=");
200	}
201
202	return true;
203	}
204
205	static bool DiagnoseNoDiscard(Sema &S, const WarnUnusedResultAttr *A,
206	SourceLocation Loc, SourceRange R1,
207	SourceRange R2, bool IsCtor) {
208	if (!A)
209	return false;
210	StringRef Msg = A->getMessage();
211
212	if (Msg.empty()) {
213	if (IsCtor)
214	return S.Diag(Loc, diag::warn_unused_constructor) << A << R1 << R2;
215	return S.Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
216	}
217
218	if (IsCtor)
219	return S.Diag(Loc, diag::warn_unused_constructor_msg) << A << Msg << R1
220	<< R2;
221	return S.Diag(Loc, diag::warn_unused_result_msg) << A << Msg << R1 << R2;
222	}
223
224	void Sema::DiagnoseUnusedExprResult(const Stmt *S, unsigned DiagID) {
225	if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(Val: S))
226	return DiagnoseUnusedExprResult(S: Label->getSubStmt(), DiagID);
227
228	const Expr *E = dyn_cast_or_null<Expr>(Val: S);
229	if (!E)
230	return;
231
232	// If we are in an unevaluated expression context, then there can be no unused
233	// results because the results aren't expected to be used in the first place.
234	if (isUnevaluatedContext())
235	return;
236
237	SourceLocation ExprLoc = E->IgnoreParenImpCasts()->getExprLoc();
238	// In most cases, we don't want to warn if the expression is written in a
239	// macro body, or if the macro comes from a system header. If the offending
240	// expression is a call to a function with the warn_unused_result attribute,
241	// we warn no matter the location. Because of the order in which the various
242	// checks need to happen, we factor out the macro-related test here.
243	bool ShouldSuppress =
244	SourceMgr.isMacroBodyExpansion(Loc: ExprLoc) ||
245	SourceMgr.isInSystemMacro(loc: ExprLoc);
246
247	const Expr *WarnExpr;
248	SourceLocation Loc;
249	SourceRange R1, R2;
250	if (!E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Ctx&: Context))
251	return;
252
253	// If this is a GNU statement expression expanded from a macro, it is probably
254	// unused because it is a function-like macro that can be used as either an
255	// expression or statement. Don't warn, because it is almost certainly a
256	// false positive.
257	if (isa<StmtExpr>(Val: E) && Loc.isMacroID())
258	return;
259
260	// Check if this is the UNREFERENCED_PARAMETER from the Microsoft headers.
261	// That macro is frequently used to suppress "unused parameter" warnings,
262	// but its implementation makes clang's -Wunused-value fire. Prevent this.
263	if (isa<ParenExpr>(Val: E->IgnoreImpCasts()) && Loc.isMacroID()) {
264	SourceLocation SpellLoc = Loc;
265	if (findMacroSpelling(loc&: SpellLoc, name: "UNREFERENCED_PARAMETER"))
266	return;
267	}
268
269	// Okay, we have an unused result. Depending on what the base expression is,
270	// we might want to make a more specific diagnostic. Check for one of these
271	// cases now.
272	if (const FullExpr *Temps = dyn_cast<FullExpr>(Val: E))
273	E = Temps->getSubExpr();
274	if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(Val: E))
275	E = TempExpr->getSubExpr();
276
277	if (DiagnoseUnusedComparison(S&: *this, E))
278	return;
279
280	E = WarnExpr;
281	if (const auto *Cast = dyn_cast<CastExpr>(Val: E))
282	if (Cast->getCastKind() == CK_NoOp ||
283	Cast->getCastKind() == CK_ConstructorConversion)
284	E = Cast->getSubExpr()->IgnoreImpCasts();
285
286	if (const CallExpr *CE = dyn_cast<CallExpr>(Val: E)) {
287	if (E->getType()->isVoidType())
288	return;
289
290	if (DiagnoseNoDiscard(*this, cast_or_null<WarnUnusedResultAttr>(
291	CE->getUnusedResultAttr(Context)),
292	Loc, R1, R2, /*isCtor=*/false))
293	return;
294
295	// If the callee has attribute pure, const, or warn_unused_result, warn with
296	// a more specific message to make it clear what is happening. If the call
297	// is written in a macro body, only warn if it has the warn_unused_result
298	// attribute.
299	if (const Decl *FD = CE->getCalleeDecl()) {
300	if (ShouldSuppress)
301	return;
302	if (FD->hasAttr<PureAttr>()) {
303	Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure";
304	return;
305	}
306	if (FD->hasAttr<ConstAttr>()) {
307	Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const";
308	return;
309	}
310	}
311	} else if (const auto *CE = dyn_cast<CXXConstructExpr>(Val: E)) {
312	if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
313	const auto *A = Ctor->getAttr<WarnUnusedResultAttr>();
314	A = A ? A : Ctor->getParent()->getAttr<WarnUnusedResultAttr>();
315	if (DiagnoseNoDiscard(*this, A, Loc, R1, R2, /*isCtor=*/true))
316	return;
317	}
318	} else if (const auto *ILE = dyn_cast<InitListExpr>(Val: E)) {
319	if (const TagDecl *TD = ILE->getType()->getAsTagDecl()) {
320
321	if (DiagnoseNoDiscard(*this, TD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
322	R2, /*isCtor=*/false))
323	return;
324	}
325	} else if (ShouldSuppress)
326	return;
327
328	E = WarnExpr;
329	if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(Val: E)) {
330	if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) {
331	Diag(Loc, diag::err_arc_unused_init_message) << R1;
332	return;
333	}
334	const ObjCMethodDecl *MD = ME->getMethodDecl();
335	if (MD) {
336	if (DiagnoseNoDiscard(*this, MD->getAttr<WarnUnusedResultAttr>(), Loc, R1,
337	R2, /*isCtor=*/false))
338	return;
339	}
340	} else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Val: E)) {
341	const Expr *Source = POE->getSyntacticForm();
342	// Handle the actually selected call of an OpenMP specialized call.
343	if (LangOpts.OpenMP && isa<CallExpr>(Val: Source) &&
344	POE->getNumSemanticExprs() == 1 &&
345	isa<CallExpr>(Val: POE->getSemanticExpr(index: 0)))
346	return DiagnoseUnusedExprResult(POE->getSemanticExpr(index: 0), DiagID);
347	if (isa<ObjCSubscriptRefExpr>(Source))
348	DiagID = diag::warn_unused_container_subscript_expr;
349	else if (isa<ObjCPropertyRefExpr>(Source))
350	DiagID = diag::warn_unused_property_expr;
351	} else if (const CXXFunctionalCastExpr *FC
352	= dyn_cast<CXXFunctionalCastExpr>(Val: E)) {
353	const Expr *E = FC->getSubExpr();
354	if (const CXXBindTemporaryExpr *TE = dyn_cast<CXXBindTemporaryExpr>(Val: E))
355	E = TE->getSubExpr();
356	if (isa<CXXTemporaryObjectExpr>(Val: E))
357	return;
358	if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: E))
359	if (const CXXRecordDecl *RD = CE->getType()->getAsCXXRecordDecl())
360	if (!RD->getAttr<WarnUnusedAttr>())
361	return;
362	}
363	// Diagnose "(void*) blah" as a typo for "(void) blah".
364	else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(Val: E)) {
365	TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
366	QualType T = TI->getType();
367
368	// We really do want to use the non-canonical type here.
369	if (T == Context.VoidPtrTy) {
370	PointerTypeLoc TL = TI->getTypeLoc().castAs<PointerTypeLoc>();
371
372	Diag(Loc, diag::warn_unused_voidptr)
373	<< FixItHint::CreateRemoval(TL.getStarLoc());
374	return;
375	}
376	}
377
378	// Tell the user to assign it into a variable to force a volatile load if this
379	// isn't an array.
380	if (E->isGLValue() && E->getType().isVolatileQualified() &&
381	!E->getType()->isArrayType()) {
382	Diag(Loc, diag::warn_unused_volatile) << R1 << R2;
383	return;
384	}
385
386	// Do not diagnose use of a comma operator in a SFINAE context because the
387	// type of the left operand could be used for SFINAE, so technically it is
388	// *used*.
389	if (DiagID != diag::warn_unused_comma_left_operand || !isSFINAEContext())
390	DiagIfReachable(Loc, Stmts: S ? llvm::ArrayRef(S) : std::nullopt,
391	PD: PDiag(DiagID) << R1 << R2);
392	}
393
394	void Sema::ActOnStartOfCompoundStmt(bool IsStmtExpr) {
395	PushCompoundScope(IsStmtExpr);
396	}
397
398	void Sema::ActOnAfterCompoundStatementLeadingPragmas() {
399	if (getCurFPFeatures().isFPConstrained()) {
400	FunctionScopeInfo *FSI = getCurFunction();
401	assert(FSI);
402	FSI->setUsesFPIntrin();
403	}
404	}
405
406	void Sema::ActOnFinishOfCompoundStmt() {
407	PopCompoundScope();
408	}
409
410	sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
411	return getCurFunction()->CompoundScopes.back();
412	}
413
414	StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
415	ArrayRef<Stmt *> Elts, bool isStmtExpr) {
416	const unsigned NumElts = Elts.size();
417
418	// If we're in C mode, check that we don't have any decls after stmts. If
419	// so, emit an extension diagnostic in C89 and potentially a warning in later
420	// versions.
421	const unsigned MixedDeclsCodeID = getLangOpts().C99
422	? diag::warn_mixed_decls_code
423	: diag::ext_mixed_decls_code;
424	if (!getLangOpts().CPlusPlus && !Diags.isIgnored(DiagID: MixedDeclsCodeID, Loc: L)) {
425	// Note that __extension__ can be around a decl.
426	unsigned i = 0;
427	// Skip over all declarations.
428	for (; i != NumElts && isa<DeclStmt>(Val: Elts[i]); ++i)
429	/*empty*/;
430
431	// We found the end of the list or a statement. Scan for another declstmt.
432	for (; i != NumElts && !isa<DeclStmt>(Val: Elts[i]); ++i)
433	/*empty*/;
434
435	if (i != NumElts) {
436	Decl *D = *cast<DeclStmt>(Val: Elts[i])->decl_begin();
437	Diag(D->getLocation(), MixedDeclsCodeID);
438	}
439	}
440
441	// Check for suspicious empty body (null statement) in `for' and `while'
442	// statements. Don't do anything for template instantiations, this just adds
443	// noise.
444	if (NumElts != 0 && !CurrentInstantiationScope &&
445	getCurCompoundScope().HasEmptyLoopBodies) {
446	for (unsigned i = 0; i != NumElts - 1; ++i)
447	DiagnoseEmptyLoopBody(S: Elts[i], PossibleBody: Elts[i + 1]);
448	}
449
450	// Calculate difference between FP options in this compound statement and in
451	// the enclosing one. If this is a function body, take the difference against
452	// default options. In this case the difference will indicate options that are
453	// changed upon entry to the statement.
454	FPOptions FPO = (getCurFunction()->CompoundScopes.size() == 1)
455	? FPOptions(getLangOpts())
456	: getCurCompoundScope().InitialFPFeatures;
457	FPOptionsOverride FPDiff = getCurFPFeatures().getChangesFrom(Base: FPO);
458
459	return CompoundStmt::Create(C: Context, Stmts: Elts, FPFeatures: FPDiff, LB: L, RB: R);
460	}
461
462	ExprResult
463	Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
464	if (!Val.get())
465	return Val;
466
467	if (DiagnoseUnexpandedParameterPack(E: Val.get()))
468	return ExprError();
469
470	// If we're not inside a switch, let the 'case' statement handling diagnose
471	// this. Just clean up after the expression as best we can.
472	if (getCurFunction()->SwitchStack.empty())
473	return ActOnFinishFullExpr(Expr: Val.get(), CC: Val.get()->getExprLoc(), DiscardedValue: false,
474	IsConstexpr: getLangOpts().CPlusPlus11);
475
476	Expr *CondExpr =
477	getCurFunction()->SwitchStack.back().getPointer()->getCond();
478	if (!CondExpr)
479	return ExprError();
480	QualType CondType = CondExpr->getType();
481
482	auto CheckAndFinish = [&](Expr *E) {
483	if (CondType->isDependentType() || E->isTypeDependent())
484	return ExprResult(E);
485
486	if (getLangOpts().CPlusPlus11) {
487	// C++11 [stmt.switch]p2: the constant-expression shall be a converted
488	// constant expression of the promoted type of the switch condition.
489	llvm::APSInt TempVal;
490	return CheckConvertedConstantExpression(From: E, T: CondType, Value&: TempVal,
491	CCE: CCEK_CaseValue);
492	}
493
494	ExprResult ER = E;
495	if (!E->isValueDependent())
496	ER = VerifyIntegerConstantExpression(E, CanFold: AllowFold);
497	if (!ER.isInvalid())
498	ER = DefaultLvalueConversion(E: ER.get());
499	if (!ER.isInvalid())
500	ER = ImpCastExprToType(E: ER.get(), Type: CondType, CK: CK_IntegralCast);
501	if (!ER.isInvalid())
502	ER = ActOnFinishFullExpr(Expr: ER.get(), CC: ER.get()->getExprLoc(), DiscardedValue: false);
503	return ER;
504	};
505
506	ExprResult Converted = CorrectDelayedTyposInExpr(
507	ER: Val, /*InitDecl=*/nullptr, /*RecoverUncorrectedTypos=*/false,
508	Filter: CheckAndFinish);
509	if (Converted.get() == Val.get())
510	Converted = CheckAndFinish(Val.get());
511	return Converted;
512	}
513
514	StmtResult
515	Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
516	SourceLocation DotDotDotLoc, ExprResult RHSVal,
517	SourceLocation ColonLoc) {
518	assert((LHSVal.isInvalid() || LHSVal.get()) && "missing LHS value");
519	assert((DotDotDotLoc.isInvalid() ? RHSVal.isUnset()
520	: RHSVal.isInvalid() || RHSVal.get()) &&
521	"missing RHS value");
522
523	if (getCurFunction()->SwitchStack.empty()) {
524	Diag(CaseLoc, diag::err_case_not_in_switch);
525	return StmtError();
526	}
527
528	if (LHSVal.isInvalid() || RHSVal.isInvalid()) {
529	getCurFunction()->SwitchStack.back().setInt(true);
530	return StmtError();
531	}
532
533	if (LangOpts.OpenACC &&
534	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
535	Diag(CaseLoc, diag::err_acc_branch_in_out_compute_construct)
536	<< /*branch*/ 0 << /*into*/ 1;
537	return StmtError();
538	}
539
540	auto *CS = CaseStmt::Create(Ctx: Context, lhs: LHSVal.get(), rhs: RHSVal.get(),
541	caseLoc: CaseLoc, ellipsisLoc: DotDotDotLoc, colonLoc: ColonLoc);
542	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(CS);
543	return CS;
544	}
545
546	/// ActOnCaseStmtBody - This installs a statement as the body of a case.
547	void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
548	cast<CaseStmt>(Val: S)->setSubStmt(SubStmt);
549	}
550
551	StmtResult
552	Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
553	Stmt *SubStmt, Scope *CurScope) {
554	if (getCurFunction()->SwitchStack.empty()) {
555	Diag(DefaultLoc, diag::err_default_not_in_switch);
556	return SubStmt;
557	}
558
559	if (LangOpts.OpenACC &&
560	getCurScope()->isInOpenACCComputeConstructScope(Flags: Scope::SwitchScope)) {
561	Diag(DefaultLoc, diag::err_acc_branch_in_out_compute_construct)
562	<< /*branch*/ 0 << /*into*/ 1;
563	return StmtError();
564	}
565
566	DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt);
567	getCurFunction()->SwitchStack.back().getPointer()->addSwitchCase(SC: DS);
568	return DS;
569	}
570
571	StmtResult
572	Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl,
573	SourceLocation ColonLoc, Stmt *SubStmt) {
574	// If the label was multiply defined, reject it now.
575	if (TheDecl->getStmt()) {
576	Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName();
577	Diag(TheDecl->getLocation(), diag::note_previous_definition);
578	return SubStmt;
579	}
580
581	ReservedIdentifierStatus Status = TheDecl->isReserved(getLangOpts());
582	if (isReservedInAllContexts(Status) &&
583	!Context.getSourceManager().isInSystemHeader(IdentLoc))
584	Diag(IdentLoc, diag::warn_reserved_extern_symbol)
585	<< TheDecl << static_cast<int>(Status);
586
587	// If this label is in a compute construct scope, we need to make sure we
588	// check gotos in/out.
589	if (getCurScope()->isInOpenACCComputeConstructScope())
590	setFunctionHasBranchProtectedScope();
591
592	// Otherwise, things are good. Fill in the declaration and return it.
593	LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt);
594	TheDecl->setStmt(LS);
595	if (!TheDecl->isGnuLocal()) {
596	TheDecl->setLocStart(IdentLoc);
597	if (!TheDecl->isMSAsmLabel()) {
598	// Don't update the location of MS ASM labels. These will result in
599	// a diagnostic, and changing the location here will mess that up.
600	TheDecl->setLocation(IdentLoc);
601	}
602	}
603	return LS;
604	}
605
606	StmtResult Sema::BuildAttributedStmt(SourceLocation AttrsLoc,
607	ArrayRef<const Attr *> Attrs,
608	Stmt *SubStmt) {
609	// FIXME: this code should move when a planned refactoring around statement
610	// attributes lands.
611	for (const auto *A : Attrs) {
612	if (A->getKind() == attr::MustTail) {
613	if (!checkAndRewriteMustTailAttr(St: SubStmt, MTA: *A)) {
614	return SubStmt;
615	}
616	setFunctionHasMustTail();
617	}
618	}
619
620	return AttributedStmt::Create(C: Context, Loc: AttrsLoc, Attrs, SubStmt);
621	}
622
623	StmtResult Sema::ActOnAttributedStmt(const ParsedAttributes &Attrs,
624	Stmt *SubStmt) {
625	SmallVector<const Attr *, 1> SemanticAttrs;
626	ProcessStmtAttributes(Stmt: SubStmt, InAttrs: Attrs, OutAttrs&: SemanticAttrs);
627	if (!SemanticAttrs.empty())
628	return BuildAttributedStmt(AttrsLoc: Attrs.Range.getBegin(), Attrs: SemanticAttrs, SubStmt);
629	// If none of the attributes applied, that's fine, we can recover by
630	// returning the substatement directly instead of making an AttributedStmt
631	// with no attributes on it.
632	return SubStmt;
633	}
634
635	bool Sema::checkAndRewriteMustTailAttr(Stmt *St, const Attr &MTA) {
636	ReturnStmt *R = cast<ReturnStmt>(Val: St);
637	Expr *E = R->getRetValue();
638
639	if (CurContext->isDependentContext() || (E && E->isInstantiationDependent()))
640	// We have to suspend our check until template instantiation time.
641	return true;
642
643	if (!checkMustTailAttr(St, MTA))
644	return false;
645
646	// FIXME: Replace Expr::IgnoreImplicitAsWritten() with this function.
647	// Currently it does not skip implicit constructors in an initialization
648	// context.
649	auto IgnoreImplicitAsWritten = [](Expr *E) -> Expr * {
650	return IgnoreExprNodes(E, Fns&: IgnoreImplicitAsWrittenSingleStep,
651	Fns&: IgnoreElidableImplicitConstructorSingleStep);
652	};
653
654	// Now that we have verified that 'musttail' is valid here, rewrite the
655	// return value to remove all implicit nodes, but retain parentheses.
656	R->setRetValue(IgnoreImplicitAsWritten(E));
657	return true;
658	}
659
660	bool Sema::checkMustTailAttr(const Stmt *St, const Attr &MTA) {
661	assert(!CurContext->isDependentContext() &&
662	"musttail cannot be checked from a dependent context");
663
664	// FIXME: Add Expr::IgnoreParenImplicitAsWritten() with this definition.
665	auto IgnoreParenImplicitAsWritten = [](const Expr *E) -> const Expr * {
666	return IgnoreExprNodes(E: const_cast<Expr *>(E), Fns&: IgnoreParensSingleStep,
667	Fns&: IgnoreImplicitAsWrittenSingleStep,
668	Fns&: IgnoreElidableImplicitConstructorSingleStep);
669	};
670
671	const Expr *E = cast<ReturnStmt>(Val: St)->getRetValue();
672	const auto *CE = dyn_cast_or_null<CallExpr>(Val: IgnoreParenImplicitAsWritten(E));
673
674	if (!CE) {
675	Diag(St->getBeginLoc(), diag::err_musttail_needs_call) << &MTA;
676	return false;
677	}
678
679	if (const auto *EWC = dyn_cast<ExprWithCleanups>(Val: E)) {
680	if (EWC->cleanupsHaveSideEffects()) {
681	Diag(St->getBeginLoc(), diag::err_musttail_needs_trivial_args) << &MTA;
682	return false;
683	}
684	}
685
686	// We need to determine the full function type (including "this" type, if any)
687	// for both caller and callee.
688	struct FuncType {
689	enum {
690	ft_non_member,
691	ft_static_member,
692	ft_non_static_member,
693	ft_pointer_to_member,
694	} MemberType = ft_non_member;
695
696	QualType This;
697	const FunctionProtoType *Func;
698	const CXXMethodDecl *Method = nullptr;
699	} CallerType, CalleeType;
700
701	auto GetMethodType = [this, St, MTA](const CXXMethodDecl *CMD, FuncType &Type,
702	bool IsCallee) -> bool {
703	if (isa<CXXConstructorDecl, CXXDestructorDecl>(Val: CMD)) {
704	Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
705	<< IsCallee << isa<CXXDestructorDecl>(CMD);
706	if (IsCallee)
707	Diag(CMD->getBeginLoc(), diag::note_musttail_structors_forbidden)
708	<< isa<CXXDestructorDecl>(CMD);
709	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
710	return false;
711	}
712	if (CMD->isStatic())
713	Type.MemberType = FuncType::ft_static_member;
714	else {
715	Type.This = CMD->getFunctionObjectParameterType();
716	Type.MemberType = FuncType::ft_non_static_member;
717	}
718	Type.Func = CMD->getType()->castAs<FunctionProtoType>();
719	return true;
720	};
721
722	const auto *CallerDecl = dyn_cast<FunctionDecl>(Val: CurContext);
723
724	// Find caller function signature.
725	if (!CallerDecl) {
726	int ContextType;
727	if (isa<BlockDecl>(Val: CurContext))
728	ContextType = 0;
729	else if (isa<ObjCMethodDecl>(Val: CurContext))
730	ContextType = 1;
731	else
732	ContextType = 2;
733	Diag(St->getBeginLoc(), diag::err_musttail_forbidden_from_this_context)
734	<< &MTA << ContextType;
735	return false;
736	} else if (const auto *CMD = dyn_cast<CXXMethodDecl>(Val: CurContext)) {
737	// Caller is a class/struct method.
738	if (!GetMethodType(CMD, CallerType, false))
739	return false;
740	} else {
741	// Caller is a non-method function.
742	CallerType.Func = CallerDecl->getType()->getAs<FunctionProtoType>();
743	}
744
745	const Expr *CalleeExpr = CE->getCallee()->IgnoreParens();
746	const auto *CalleeBinOp = dyn_cast<BinaryOperator>(Val: CalleeExpr);
747	SourceLocation CalleeLoc = CE->getCalleeDecl()
748	? CE->getCalleeDecl()->getBeginLoc()
749	: St->getBeginLoc();
750
751	// Find callee function signature.
752	if (const CXXMethodDecl *CMD =
753	dyn_cast_or_null<CXXMethodDecl>(Val: CE->getCalleeDecl())) {
754	// Call is: obj.method(), obj->method(), functor(), etc.
755	if (!GetMethodType(CMD, CalleeType, true))
756	return false;
757	} else if (CalleeBinOp && CalleeBinOp->isPtrMemOp()) {
758	// Call is: obj->*method_ptr or obj.*method_ptr
759	const auto *MPT =
760	CalleeBinOp->getRHS()->getType()->castAs<MemberPointerType>();
761	CalleeType.This = QualType(MPT->getClass(), 0);
762	CalleeType.Func = MPT->getPointeeType()->castAs<FunctionProtoType>();
763	CalleeType.MemberType = FuncType::ft_pointer_to_member;
764	} else if (isa<CXXPseudoDestructorExpr>(Val: CalleeExpr)) {
765	Diag(St->getBeginLoc(), diag::err_musttail_structors_forbidden)
766	<< /* IsCallee = */ 1 << /* IsDestructor = */ 1;
767	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
768	return false;
769	} else {
770	// Non-method function.
771	CalleeType.Func =
772	CalleeExpr->getType()->getPointeeType()->getAs<FunctionProtoType>();
773	}
774
775	// Both caller and callee must have a prototype (no K&R declarations).
776	if (!CalleeType.Func || !CallerType.Func) {
777	Diag(St->getBeginLoc(), diag::err_musttail_needs_prototype) << &MTA;
778	if (!CalleeType.Func && CE->getDirectCallee()) {
779	Diag(CE->getDirectCallee()->getBeginLoc(),
780	diag::note_musttail_fix_non_prototype);
781	}
782	if (!CallerType.Func)
783	Diag(CallerDecl->getBeginLoc(), diag::note_musttail_fix_non_prototype);
784	return false;
785	}
786
787	// Caller and callee must have matching calling conventions.
788	//
789	// Some calling conventions are physically capable of supporting tail calls
790	// even if the function types don't perfectly match. LLVM is currently too
791	// strict to allow this, but if LLVM added support for this in the future, we
792	// could exit early here and skip the remaining checks if the functions are
793	// using such a calling convention.
794	if (CallerType.Func->getCallConv() != CalleeType.Func->getCallConv()) {
795	if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
796	Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch)
797	<< true << ND->getDeclName();
798	else
799	Diag(St->getBeginLoc(), diag::err_musttail_callconv_mismatch) << false;
800	Diag(CalleeLoc, diag::note_musttail_callconv_mismatch)
801	<< FunctionType::getNameForCallConv(CallerType.Func->getCallConv())
802	<< FunctionType::getNameForCallConv(CalleeType.Func->getCallConv());
803	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
804	return false;
805	}
806
807	if (CalleeType.Func->isVariadic() || CallerType.Func->isVariadic()) {
808	Diag(St->getBeginLoc(), diag::err_musttail_no_variadic) << &MTA;
809	return false;
810	}
811
812	const auto *CalleeDecl = CE->getCalleeDecl();
813	if (CalleeDecl && CalleeDecl->hasAttr<CXX11NoReturnAttr>()) {
814	Diag(St->getBeginLoc(), diag::err_musttail_no_return) << &MTA;
815	return false;
816	}
817
818	// Caller and callee must match in whether they have a "this" parameter.
819	if (CallerType.This.isNull() != CalleeType.This.isNull()) {
820	if (const auto *ND = dyn_cast_or_null<NamedDecl>(Val: CE->getCalleeDecl())) {
821	Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
822	<< CallerType.MemberType << CalleeType.MemberType << true
823	<< ND->getDeclName();
824	Diag(CalleeLoc, diag::note_musttail_callee_defined_here)
825	<< ND->getDeclName();
826	} else
827	Diag(St->getBeginLoc(), diag::err_musttail_member_mismatch)
828	<< CallerType.MemberType << CalleeType.MemberType << false;
829	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
830	return false;
831	}
832
833	auto CheckTypesMatch = [this](FuncType CallerType, FuncType CalleeType,
834	PartialDiagnostic &PD) -> bool {
835	enum {
836	ft_different_class,
837	ft_parameter_arity,
838	ft_parameter_mismatch,
839	ft_return_type,
840	};
841
842	auto DoTypesMatch = [this, &PD](QualType A, QualType B,
843	unsigned Select) -> bool {
844	if (!Context.hasSimilarType(T1: A, T2: B)) {
845	PD << Select << A.getUnqualifiedType() << B.getUnqualifiedType();
846	return false;
847	}
848	return true;
849	};
850
851	if (!CallerType.This.isNull() &&
852	!DoTypesMatch(CallerType.This, CalleeType.This, ft_different_class))
853	return false;
854
855	if (!DoTypesMatch(CallerType.Func->getReturnType(),
856	CalleeType.Func->getReturnType(), ft_return_type))
857	return false;
858
859	if (CallerType.Func->getNumParams() != CalleeType.Func->getNumParams()) {
860	PD << ft_parameter_arity << CallerType.Func->getNumParams()
861	<< CalleeType.Func->getNumParams();
862	return false;
863	}
864
865	ArrayRef<QualType> CalleeParams = CalleeType.Func->getParamTypes();
866	ArrayRef<QualType> CallerParams = CallerType.Func->getParamTypes();
867	size_t N = CallerType.Func->getNumParams();
868	for (size_t I = 0; I < N; I++) {
869	if (!DoTypesMatch(CalleeParams[I], CallerParams[I],
870	ft_parameter_mismatch)) {
871	PD << static_cast<int>(I) + 1;
872	return false;
873	}
874	}
875
876	return true;
877	};
878
879	PartialDiagnostic PD = PDiag(diag::note_musttail_mismatch);
880	if (!CheckTypesMatch(CallerType, CalleeType, PD)) {
881	if (const auto *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl()))
882	Diag(St->getBeginLoc(), diag::err_musttail_mismatch)
883	<< true << ND->getDeclName();
884	else
885	Diag(St->getBeginLoc(), diag::err_musttail_mismatch) << false;
886	Diag(CalleeLoc, PD);
887	Diag(MTA.getLocation(), diag::note_tail_call_required) << &MTA;
888	return false;
889	}
890
891	return true;
892	}
893
894	namespace {
895	class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
896	typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
897	Sema &SemaRef;
898	public:
899	CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
900	void VisitBinaryOperator(BinaryOperator *E) {
901	if (E->getOpcode() == BO_Comma)
902	SemaRef.DiagnoseCommaOperator(LHS: E->getLHS(), Loc: E->getExprLoc());
903	EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
904	}
905	};
906	}
907
908	StmtResult Sema::ActOnIfStmt(SourceLocation IfLoc,
909	IfStatementKind StatementKind,
910	SourceLocation LParenLoc, Stmt *InitStmt,
911	ConditionResult Cond, SourceLocation RParenLoc,
912	Stmt *thenStmt, SourceLocation ElseLoc,
913	Stmt *elseStmt) {
914	if (Cond.isInvalid())
915	return StmtError();
916
917	bool ConstevalOrNegatedConsteval =
918	StatementKind == IfStatementKind::ConstevalNonNegated ||
919	StatementKind == IfStatementKind::ConstevalNegated;
920
921	Expr *CondExpr = Cond.get().second;
922	assert((CondExpr || ConstevalOrNegatedConsteval) &&
923	"If statement: missing condition");
924	// Only call the CommaVisitor when not C89 due to differences in scope flags.
925	if (CondExpr && (getLangOpts().C99 || getLangOpts().CPlusPlus) &&
926	!Diags.isIgnored(diag::warn_comma_operator, CondExpr->getExprLoc()))
927	CommaVisitor(*this).Visit(CondExpr);
928
929	if (!ConstevalOrNegatedConsteval && !elseStmt)
930	DiagnoseEmptyStmtBody(RParenLoc, thenStmt, diag::warn_empty_if_body);
931
932	if (ConstevalOrNegatedConsteval ||
933	StatementKind == IfStatementKind::Constexpr) {
934	auto DiagnoseLikelihood = [&](const Stmt *S) {
935	if (const Attr *A = Stmt::getLikelihoodAttr(S)) {
936	Diags.Report(A->getLocation(),
937	diag::warn_attribute_has_no_effect_on_compile_time_if)
938	<< A << ConstevalOrNegatedConsteval << A->getRange();
939	Diags.Report(IfLoc,
940	diag::note_attribute_has_no_effect_on_compile_time_if_here)
941	<< ConstevalOrNegatedConsteval
942	<< SourceRange(IfLoc, (ConstevalOrNegatedConsteval
943	? thenStmt->getBeginLoc()
944	: LParenLoc)
945	.getLocWithOffset(-1));
946	}
947	};
948	DiagnoseLikelihood(thenStmt);
949	DiagnoseLikelihood(elseStmt);
950	} else {
951	std::tuple<bool, const Attr *, const Attr *> LHC =
952	Stmt::determineLikelihoodConflict(Then: thenStmt, Else: elseStmt);
953	if (std::get<0>(t&: LHC)) {
954	const Attr *ThenAttr = std::get<1>(t&: LHC);
955	const Attr *ElseAttr = std::get<2>(t&: LHC);
956	Diags.Report(ThenAttr->getLocation(),
957	diag::warn_attributes_likelihood_ifstmt_conflict)
958	<< ThenAttr << ThenAttr->getRange();
959	Diags.Report(ElseAttr->getLocation(), diag::note_conflicting_attribute)
960	<< ElseAttr << ElseAttr->getRange();
961	}
962	}
963
964	if (ConstevalOrNegatedConsteval) {
965	bool Immediate = ExprEvalContexts.back().Context ==
966	ExpressionEvaluationContext::ImmediateFunctionContext;
967	if (CurContext->isFunctionOrMethod()) {
968	const auto *FD =
969	dyn_cast<FunctionDecl>(Val: Decl::castFromDeclContext(CurContext));
970	if (FD && FD->isImmediateFunction())
971	Immediate = true;
972	}
973	if (isUnevaluatedContext() || Immediate)
974	Diags.Report(IfLoc, diag::warn_consteval_if_always_true) << Immediate;
975	}
976
977	return BuildIfStmt(IfLoc, StatementKind, LParenLoc, InitStmt, Cond, RParenLoc,
978	ThenVal: thenStmt, ElseLoc, ElseVal: elseStmt);
979	}
980
981	StmtResult Sema::BuildIfStmt(SourceLocation IfLoc,
982	IfStatementKind StatementKind,
983	SourceLocation LParenLoc, Stmt *InitStmt,
984	ConditionResult Cond, SourceLocation RParenLoc,
985	Stmt *thenStmt, SourceLocation ElseLoc,
986	Stmt *elseStmt) {
987	if (Cond.isInvalid())
988	return StmtError();
989
990	if (StatementKind != IfStatementKind::Ordinary ||
991	isa<ObjCAvailabilityCheckExpr>(Val: Cond.get().second))
992	setFunctionHasBranchProtectedScope();
993
994	return IfStmt::Create(Ctx: Context, IL: IfLoc, Kind: StatementKind, Init: InitStmt,
995	Var: Cond.get().first, Cond: Cond.get().second, LPL: LParenLoc,
996	RPL: RParenLoc, Then: thenStmt, EL: ElseLoc, Else: elseStmt);
997	}
998
999	namespace {
1000	struct CaseCompareFunctor {
1001	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1002	const llvm::APSInt &RHS) {
1003	return LHS.first < RHS;
1004	}
1005	bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS,
1006	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1007	return LHS.first < RHS.first;
1008	}
1009	bool operator()(const llvm::APSInt &LHS,
1010	const std::pair<llvm::APSInt, CaseStmt*> &RHS) {
1011	return LHS < RHS.first;
1012	}
1013	};
1014	}
1015
1016	/// CmpCaseVals - Comparison predicate for sorting case values.
1017	///
1018	static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs,
1019	const std::pair<llvm::APSInt, CaseStmt*>& rhs) {
1020	if (lhs.first < rhs.first)
1021	return true;
1022
1023	if (lhs.first == rhs.first &&
1024	lhs.second->getCaseLoc() < rhs.second->getCaseLoc())
1025	return true;
1026	return false;
1027	}
1028
1029	/// CmpEnumVals - Comparison predicate for sorting enumeration values.
1030	///
1031	static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1032	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1033	{
1034	return lhs.first < rhs.first;
1035	}
1036
1037	/// EqEnumVals - Comparison preficate for uniqing enumeration values.
1038	///
1039	static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
1040	const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs)
1041	{
1042	return lhs.first == rhs.first;
1043	}
1044
1045	/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
1046	/// potentially integral-promoted expression @p expr.
1047	static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
1048	if (const auto *FE = dyn_cast<FullExpr>(Val: E))
1049	E = FE->getSubExpr();
1050	while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(Val: E)) {
1051	if (ImpCast->getCastKind() != CK_IntegralCast) break;
1052	E = ImpCast->getSubExpr();
1053	}
1054	return E->getType();
1055	}
1056
1057	ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
1058	class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
1059	Expr *Cond;
1060
1061	public:
1062	SwitchConvertDiagnoser(Expr *Cond)
1063	: ICEConvertDiagnoser(/*AllowScopedEnumerations*/true, false, true),
1064	Cond(Cond) {}
1065
1066	SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
1067	QualType T) override {
1068	return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T;
1069	}
1070
1071	SemaDiagnosticBuilder diagnoseIncomplete(
1072	Sema &S, SourceLocation Loc, QualType T) override {
1073	return S.Diag(Loc, diag::err_switch_incomplete_class_type)
1074	<< T << Cond->getSourceRange();
1075	}
1076
1077	SemaDiagnosticBuilder diagnoseExplicitConv(
1078	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1079	return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy;
1080	}
1081
1082	SemaDiagnosticBuilder noteExplicitConv(
1083	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1084	return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1085	<< ConvTy->isEnumeralType() << ConvTy;
1086	}
1087
1088	SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
1089	QualType T) override {
1090	return S.Diag(Loc, diag::err_switch_multiple_conversions) << T;
1091	}
1092
1093	SemaDiagnosticBuilder noteAmbiguous(
1094	Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
1095	return S.Diag(Conv->getLocation(), diag::note_switch_conversion)
1096	<< ConvTy->isEnumeralType() << ConvTy;
1097	}
1098
1099	SemaDiagnosticBuilder diagnoseConversion(
1100	Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
1101	llvm_unreachable("conversion functions are permitted");
1102	}
1103	} SwitchDiagnoser(Cond);
1104
1105	ExprResult CondResult =
1106	PerformContextualImplicitConversion(Loc: SwitchLoc, FromE: Cond, Converter&: SwitchDiagnoser);
1107	if (CondResult.isInvalid())
1108	return ExprError();
1109
1110	// FIXME: PerformContextualImplicitConversion doesn't always tell us if it
1111	// failed and produced a diagnostic.
1112	Cond = CondResult.get();
1113	if (!Cond->isTypeDependent() &&
1114	!Cond->getType()->isIntegralOrEnumerationType())
1115	return ExprError();
1116
1117	// C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
1118	return UsualUnaryConversions(E: Cond);
1119	}
1120
1121	StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
1122	SourceLocation LParenLoc,
1123	Stmt *InitStmt, ConditionResult Cond,
1124	SourceLocation RParenLoc) {
1125	Expr *CondExpr = Cond.get().second;
1126	assert((Cond.isInvalid() || CondExpr) && "switch with no condition");
1127
1128	if (CondExpr && !CondExpr->isTypeDependent()) {
1129	// We have already converted the expression to an integral or enumeration
1130	// type, when we parsed the switch condition. There are cases where we don't
1131	// have an appropriate type, e.g. a typo-expr Cond was corrected to an
1132	// inappropriate-type expr, we just return an error.
1133	if (!CondExpr->getType()->isIntegralOrEnumerationType())
1134	return StmtError();
1135	if (CondExpr->isKnownToHaveBooleanValue()) {
1136	// switch(bool_expr) {...} is often a programmer error, e.g.
1137	// switch(n && mask) { ... } // Doh - should be "n & mask".
1138	// One can always use an if statement instead of switch(bool_expr).
1139	Diag(SwitchLoc, diag::warn_bool_switch_condition)
1140	<< CondExpr->getSourceRange();
1141	}
1142	}
1143
1144	setFunctionHasBranchIntoScope();
1145
1146	auto *SS = SwitchStmt::Create(Ctx: Context, Init: InitStmt, Var: Cond.get().first, Cond: CondExpr,
1147	LParenLoc, RParenLoc);
1148	getCurFunction()->SwitchStack.push_back(
1149	Elt: FunctionScopeInfo::SwitchInfo(SS, false));
1150	return SS;
1151	}
1152
1153	static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) {
1154	Val = Val.extOrTrunc(width: BitWidth);
1155	Val.setIsSigned(IsSigned);
1156	}
1157
1158	/// Check the specified case value is in range for the given unpromoted switch
1159	/// type.
1160	static void checkCaseValue(Sema &S, SourceLocation Loc, const llvm::APSInt &Val,
1161	unsigned UnpromotedWidth, bool UnpromotedSign) {
1162	// In C++11 onwards, this is checked by the language rules.
1163	if (S.getLangOpts().CPlusPlus11)
1164	return;
1165
1166	// If the case value was signed and negative and the switch expression is
1167	// unsigned, don't bother to warn: this is implementation-defined behavior.
1168	// FIXME: Introduce a second, default-ignored warning for this case?
1169	if (UnpromotedWidth < Val.getBitWidth()) {
1170	llvm::APSInt ConvVal(Val);
1171	AdjustAPSInt(Val&: ConvVal, BitWidth: UnpromotedWidth, IsSigned: UnpromotedSign);
1172	AdjustAPSInt(Val&: ConvVal, BitWidth: Val.getBitWidth(), IsSigned: Val.isSigned());
1173	// FIXME: Use different diagnostics for overflow in conversion to promoted
1174	// type versus "switch expression cannot have this value". Use proper
1175	// IntRange checking rather than just looking at the unpromoted type here.
1176	if (ConvVal != Val)
1177	S.Diag(Loc, diag::warn_case_value_overflow) << toString(Val, 10)
1178	<< toString(ConvVal, 10);
1179	}
1180	}
1181
1182	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy;
1183
1184	/// Returns true if we should emit a diagnostic about this case expression not
1185	/// being a part of the enum used in the switch controlling expression.
1186	static bool ShouldDiagnoseSwitchCaseNotInEnum(const Sema &S,
1187	const EnumDecl *ED,
1188	const Expr *CaseExpr,
1189	EnumValsTy::iterator &EI,
1190	EnumValsTy::iterator &EIEnd,
1191	const llvm::APSInt &Val) {
1192	if (!ED->isClosed())
1193	return false;
1194
1195	if (const DeclRefExpr *DRE =
1196	dyn_cast<DeclRefExpr>(Val: CaseExpr->IgnoreParenImpCasts())) {
1197	if (const VarDecl *VD = dyn_cast<VarDecl>(Val: DRE->getDecl())) {
1198	QualType VarType = VD->getType();
1199	QualType EnumType = S.Context.getTypeDeclType(ED);
1200	if (VD->hasGlobalStorage() && VarType.isConstQualified() &&
1201	S.Context.hasSameUnqualifiedType(T1: EnumType, T2: VarType))
1202	return false;
1203	}
1204	}
1205
1206	if (ED->hasAttr<FlagEnumAttr>())
1207	return !S.IsValueInFlagEnum(ED, Val, AllowMask: false);
1208
1209	while (EI != EIEnd && EI->first < Val)
1210	EI++;
1211
1212	if (EI != EIEnd && EI->first == Val)
1213	return false;
1214
1215	return true;
1216	}
1217
1218	static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
1219	const Expr *Case) {
1220	QualType CondType = Cond->getType();
1221	QualType CaseType = Case->getType();
1222
1223	const EnumType *CondEnumType = CondType->getAs<EnumType>();
1224	const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
1225	if (!CondEnumType || !CaseEnumType)
1226	return;
1227
1228	// Ignore anonymous enums.
1229	if (!CondEnumType->getDecl()->getIdentifier() &&
1230	!CondEnumType->getDecl()->getTypedefNameForAnonDecl())
1231	return;
1232	if (!CaseEnumType->getDecl()->getIdentifier() &&
1233	!CaseEnumType->getDecl()->getTypedefNameForAnonDecl())
1234	return;
1235
1236	if (S.Context.hasSameUnqualifiedType(T1: CondType, T2: CaseType))
1237	return;
1238
1239	S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types_switch)
1240	<< CondType << CaseType << Cond->getSourceRange()
1241	<< Case->getSourceRange();
1242	}
1243
1244	StmtResult
1245	Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
1246	Stmt *BodyStmt) {
1247	SwitchStmt *SS = cast<SwitchStmt>(Val: Switch);
1248	bool CaseListIsIncomplete = getCurFunction()->SwitchStack.back().getInt();
1249	assert(SS == getCurFunction()->SwitchStack.back().getPointer() &&
1250	"switch stack missing push/pop!");
1251
1252	getCurFunction()->SwitchStack.pop_back();
1253
1254	if (!BodyStmt) return StmtError();
1255	SS->setBody(S: BodyStmt, SL: SwitchLoc);
1256
1257	Expr *CondExpr = SS->getCond();
1258	if (!CondExpr) return StmtError();
1259
1260	QualType CondType = CondExpr->getType();
1261
1262	// C++ 6.4.2.p2:
1263	// Integral promotions are performed (on the switch condition).
1264	//
1265	// A case value unrepresentable by the original switch condition
1266	// type (before the promotion) doesn't make sense, even when it can
1267	// be represented by the promoted type. Therefore we need to find
1268	// the pre-promotion type of the switch condition.
1269	const Expr *CondExprBeforePromotion = CondExpr;
1270	QualType CondTypeBeforePromotion =
1271	GetTypeBeforeIntegralPromotion(E&: CondExprBeforePromotion);
1272
1273	// Get the bitwidth of the switched-on value after promotions. We must
1274	// convert the integer case values to this width before comparison.
1275	bool HasDependentValue
1276	= CondExpr->isTypeDependent() || CondExpr->isValueDependent();
1277	unsigned CondWidth = HasDependentValue ? 0 : Context.getIntWidth(T: CondType);
1278	bool CondIsSigned = CondType->isSignedIntegerOrEnumerationType();
1279
1280	// Get the width and signedness that the condition might actually have, for
1281	// warning purposes.
1282	// FIXME: Grab an IntRange for the condition rather than using the unpromoted
1283	// type.
1284	unsigned CondWidthBeforePromotion
1285	= HasDependentValue ? 0 : Context.getIntWidth(T: CondTypeBeforePromotion);
1286	bool CondIsSignedBeforePromotion
1287	= CondTypeBeforePromotion->isSignedIntegerOrEnumerationType();
1288
1289	// Accumulate all of the case values in a vector so that we can sort them
1290	// and detect duplicates. This vector contains the APInt for the case after
1291	// it has been converted to the condition type.
1292	typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy;
1293	CaseValsTy CaseVals;
1294
1295	// Keep track of any GNU case ranges we see. The APSInt is the low value.
1296	typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy;
1297	CaseRangesTy CaseRanges;
1298
1299	DefaultStmt *TheDefaultStmt = nullptr;
1300
1301	bool CaseListIsErroneous = false;
1302
1303	// FIXME: We'd better diagnose missing or duplicate default labels even
1304	// in the dependent case. Because default labels themselves are never
1305	// dependent.
1306	for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue;
1307	SC = SC->getNextSwitchCase()) {
1308
1309	if (DefaultStmt *DS = dyn_cast<DefaultStmt>(Val: SC)) {
1310	if (TheDefaultStmt) {
1311	Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined);
1312	Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev);
1313
1314	// FIXME: Remove the default statement from the switch block so that
1315	// we'll return a valid AST. This requires recursing down the AST and
1316	// finding it, not something we are set up to do right now. For now,
1317	// just lop the entire switch stmt out of the AST.
1318	CaseListIsErroneous = true;
1319	}
1320	TheDefaultStmt = DS;
1321
1322	} else {
1323	CaseStmt *CS = cast<CaseStmt>(Val: SC);
1324
1325	Expr *Lo = CS->getLHS();
1326
1327	if (Lo->isValueDependent()) {
1328	HasDependentValue = true;
1329	break;
1330	}
1331
1332	// We already verified that the expression has a constant value;
1333	// get that value (prior to conversions).
1334	const Expr *LoBeforePromotion = Lo;
1335	GetTypeBeforeIntegralPromotion(E&: LoBeforePromotion);
1336	llvm::APSInt LoVal = LoBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1337
1338	// Check the unconverted value is within the range of possible values of
1339	// the switch expression.
1340	checkCaseValue(*this, Lo->getBeginLoc(), LoVal, CondWidthBeforePromotion,
1341	CondIsSignedBeforePromotion);
1342
1343	// FIXME: This duplicates the check performed for warn_not_in_enum below.
1344	checkEnumTypesInSwitchStmt(S&: *this, Cond: CondExprBeforePromotion,
1345	Case: LoBeforePromotion);
1346
1347	// Convert the value to the same width/sign as the condition.
1348	AdjustAPSInt(Val&: LoVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1349
1350	// If this is a case range, remember it in CaseRanges, otherwise CaseVals.
1351	if (CS->getRHS()) {
1352	if (CS->getRHS()->isValueDependent()) {
1353	HasDependentValue = true;
1354	break;
1355	}
1356	CaseRanges.push_back(x: std::make_pair(x&: LoVal, y&: CS));
1357	} else
1358	CaseVals.push_back(Elt: std::make_pair(x&: LoVal, y&: CS));
1359	}
1360	}
1361
1362	if (!HasDependentValue) {
1363	// If we don't have a default statement, check whether the
1364	// condition is constant.
1365	llvm::APSInt ConstantCondValue;
1366	bool HasConstantCond = false;
1367	if (!TheDefaultStmt) {
1368	Expr::EvalResult Result;
1369	HasConstantCond = CondExpr->EvaluateAsInt(Result, Ctx: Context,
1370	AllowSideEffects: Expr::SE_AllowSideEffects);
1371	if (Result.Val.isInt())
1372	ConstantCondValue = Result.Val.getInt();
1373	assert(!HasConstantCond ||
1374	(ConstantCondValue.getBitWidth() == CondWidth &&
1375	ConstantCondValue.isSigned() == CondIsSigned));
1376	Diag(SwitchLoc, diag::warn_switch_default);
1377	}
1378	bool ShouldCheckConstantCond = HasConstantCond;
1379
1380	// Sort all the scalar case values so we can easily detect duplicates.
1381	llvm::stable_sort(Range&: CaseVals, C: CmpCaseVals);
1382
1383	if (!CaseVals.empty()) {
1384	for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) {
1385	if (ShouldCheckConstantCond &&
1386	CaseVals[i].first == ConstantCondValue)
1387	ShouldCheckConstantCond = false;
1388
1389	if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) {
1390	// If we have a duplicate, report it.
1391	// First, determine if either case value has a name
1392	StringRef PrevString, CurrString;
1393	Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts();
1394	Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts();
1395	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: PrevCase)) {
1396	PrevString = DeclRef->getDecl()->getName();
1397	}
1398	if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(Val: CurrCase)) {
1399	CurrString = DeclRef->getDecl()->getName();
1400	}
1401	SmallString<16> CaseValStr;
1402	CaseVals[i-1].first.toString(Str&: CaseValStr);
1403
1404	if (PrevString == CurrString)
1405	Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1406	diag::err_duplicate_case)
1407	<< (PrevString.empty() ? CaseValStr.str() : PrevString);
1408	else
1409	Diag(CaseVals[i].second->getLHS()->getBeginLoc(),
1410	diag::err_duplicate_case_differing_expr)
1411	<< (PrevString.empty() ? CaseValStr.str() : PrevString)
1412	<< (CurrString.empty() ? CaseValStr.str() : CurrString)
1413	<< CaseValStr;
1414
1415	Diag(CaseVals[i - 1].second->getLHS()->getBeginLoc(),
1416	diag::note_duplicate_case_prev);
1417	// FIXME: We really want to remove the bogus case stmt from the
1418	// substmt, but we have no way to do this right now.
1419	CaseListIsErroneous = true;
1420	}
1421	}
1422	}
1423
1424	// Detect duplicate case ranges, which usually don't exist at all in
1425	// the first place.
1426	if (!CaseRanges.empty()) {
1427	// Sort all the case ranges by their low value so we can easily detect
1428	// overlaps between ranges.
1429	llvm::stable_sort(Range&: CaseRanges);
1430
1431	// Scan the ranges, computing the high values and removing empty ranges.
1432	std::vector<llvm::APSInt> HiVals;
1433	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1434	llvm::APSInt &LoVal = CaseRanges[i].first;
1435	CaseStmt *CR = CaseRanges[i].second;
1436	Expr *Hi = CR->getRHS();
1437
1438	const Expr *HiBeforePromotion = Hi;
1439	GetTypeBeforeIntegralPromotion(E&: HiBeforePromotion);
1440	llvm::APSInt HiVal = HiBeforePromotion->EvaluateKnownConstInt(Ctx: Context);
1441
1442	// Check the unconverted value is within the range of possible values of
1443	// the switch expression.
1444	checkCaseValue(*this, Hi->getBeginLoc(), HiVal,
1445	CondWidthBeforePromotion, CondIsSignedBeforePromotion);
1446
1447	// Convert the value to the same width/sign as the condition.
1448	AdjustAPSInt(Val&: HiVal, BitWidth: CondWidth, IsSigned: CondIsSigned);
1449
1450	// If the low value is bigger than the high value, the case is empty.
1451	if (LoVal > HiVal) {
1452	Diag(CR->getLHS()->getBeginLoc(), diag::warn_case_empty_range)
1453	<< SourceRange(CR->getLHS()->getBeginLoc(), Hi->getEndLoc());
1454	CaseRanges.erase(position: CaseRanges.begin()+i);
1455	--i;
1456	--e;
1457	continue;
1458	}
1459
1460	if (ShouldCheckConstantCond &&
1461	LoVal <= ConstantCondValue &&
1462	ConstantCondValue <= HiVal)
1463	ShouldCheckConstantCond = false;
1464
1465	HiVals.push_back(x: HiVal);
1466	}
1467
1468	// Rescan the ranges, looking for overlap with singleton values and other
1469	// ranges. Since the range list is sorted, we only need to compare case
1470	// ranges with their neighbors.
1471	for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) {
1472	llvm::APSInt &CRLo = CaseRanges[i].first;
1473	llvm::APSInt &CRHi = HiVals[i];
1474	CaseStmt *CR = CaseRanges[i].second;
1475
1476	// Check to see whether the case range overlaps with any
1477	// singleton cases.
1478	CaseStmt *OverlapStmt = nullptr;
1479	llvm::APSInt OverlapVal(32);
1480
1481	// Find the smallest value >= the lower bound. If I is in the
1482	// case range, then we have overlap.
1483	CaseValsTy::iterator I =
1484	llvm::lower_bound(Range&: CaseVals, Value&: CRLo, C: CaseCompareFunctor());
1485	if (I != CaseVals.end() && I->first < CRHi) {
1486	OverlapVal = I->first; // Found overlap with scalar.
1487	OverlapStmt = I->second;
1488	}
1489
1490	// Find the smallest value bigger than the upper bound.
1491	I = std::upper_bound(first: I, last: CaseVals.end(), val: CRHi, comp: CaseCompareFunctor());
1492	if (I != CaseVals.begin() && (I-1)->first >= CRLo) {
1493	OverlapVal = (I-1)->first; // Found overlap with scalar.
1494	OverlapStmt = (I-1)->second;
1495	}
1496
1497	// Check to see if this case stmt overlaps with the subsequent
1498	// case range.
1499	if (i && CRLo <= HiVals[i-1]) {
1500	OverlapVal = HiVals[i-1]; // Found overlap with range.
1501	OverlapStmt = CaseRanges[i-1].second;
1502	}
1503
1504	if (OverlapStmt) {
1505	// If we have a duplicate, report it.
1506	Diag(CR->getLHS()->getBeginLoc(), diag::err_duplicate_case)
1507	<< toString(OverlapVal, 10);
1508	Diag(OverlapStmt->getLHS()->getBeginLoc(),
1509	diag::note_duplicate_case_prev);
1510	// FIXME: We really want to remove the bogus case stmt from the
1511	// substmt, but we have no way to do this right now.
1512	CaseListIsErroneous = true;
1513	}
1514	}
1515	}
1516
1517	// Complain if we have a constant condition and we didn't find a match.
1518	if (!CaseListIsErroneous && !CaseListIsIncomplete &&
1519	ShouldCheckConstantCond) {
1520	// TODO: it would be nice if we printed enums as enums, chars as
1521	// chars, etc.
1522	Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition)
1523	<< toString(ConstantCondValue, 10)
1524	<< CondExpr->getSourceRange();
1525	}
1526
1527	// Check to see if switch is over an Enum and handles all of its
1528	// values. We only issue a warning if there is not 'default:', but
1529	// we still do the analysis to preserve this information in the AST
1530	// (which can be used by flow-based analyes).
1531	//
1532	const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>();
1533
1534	// If switch has default case, then ignore it.
1535	if (!CaseListIsErroneous && !CaseListIsIncomplete && !HasConstantCond &&
1536	ET && ET->getDecl()->isCompleteDefinition() &&
1537	!ET->getDecl()->enumerators().empty()) {
1538	const EnumDecl *ED = ET->getDecl();
1539	EnumValsTy EnumVals;
1540
1541	// Gather all enum values, set their type and sort them,
1542	// allowing easier comparison with CaseVals.
1543	for (auto *EDI : ED->enumerators()) {
1544	llvm::APSInt Val = EDI->getInitVal();
1545	AdjustAPSInt(Val, BitWidth: CondWidth, IsSigned: CondIsSigned);
1546	EnumVals.push_back(Elt: std::make_pair(x&: Val, y&: EDI));
1547	}
1548	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1549	auto EI = EnumVals.begin(), EIEnd =
1550	std::unique(first: EnumVals.begin(), last: EnumVals.end(), binary_pred: EqEnumVals);
1551
1552	// See which case values aren't in enum.
1553	for (CaseValsTy::const_iterator CI = CaseVals.begin();
1554	CI != CaseVals.end(); CI++) {
1555	Expr *CaseExpr = CI->second->getLHS();
1556	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1557	CI->first))
1558	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1559	<< CondTypeBeforePromotion;
1560	}
1561
1562	// See which of case ranges aren't in enum
1563	EI = EnumVals.begin();
1564	for (CaseRangesTy::const_iterator RI = CaseRanges.begin();
1565	RI != CaseRanges.end(); RI++) {
1566	Expr *CaseExpr = RI->second->getLHS();
1567	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1568	RI->first))
1569	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1570	<< CondTypeBeforePromotion;
1571
1572	llvm::APSInt Hi =
1573	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1574	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1575
1576	CaseExpr = RI->second->getRHS();
1577	if (ShouldDiagnoseSwitchCaseNotInEnum(*this, ED, CaseExpr, EI, EIEnd,
1578	Hi))
1579	Diag(CaseExpr->getExprLoc(), diag::warn_not_in_enum)
1580	<< CondTypeBeforePromotion;
1581	}
1582
1583	// Check which enum vals aren't in switch
1584	auto CI = CaseVals.begin();
1585	auto RI = CaseRanges.begin();
1586	bool hasCasesNotInSwitch = false;
1587
1588	SmallVector<DeclarationName,8> UnhandledNames;
1589
1590	for (EI = EnumVals.begin(); EI != EIEnd; EI++) {
1591	// Don't warn about omitted unavailable EnumConstantDecls.
1592	switch (EI->second->getAvailability()) {
1593	case AR_Deprecated:
1594	// Omitting a deprecated constant is ok; it should never materialize.
1595	case AR_Unavailable:
1596	continue;
1597
1598	case AR_NotYetIntroduced:
1599	// Partially available enum constants should be present. Note that we
1600	// suppress -Wunguarded-availability diagnostics for such uses.
1601	case AR_Available:
1602	break;
1603	}
1604
1605	if (EI->second->hasAttr<UnusedAttr>())
1606	continue;
1607
1608	// Drop unneeded case values
1609	while (CI != CaseVals.end() && CI->first < EI->first)
1610	CI++;
1611
1612	if (CI != CaseVals.end() && CI->first == EI->first)
1613	continue;
1614
1615	// Drop unneeded case ranges
1616	for (; RI != CaseRanges.end(); RI++) {
1617	llvm::APSInt Hi =
1618	RI->second->getRHS()->EvaluateKnownConstInt(Ctx: Context);
1619	AdjustAPSInt(Val&: Hi, BitWidth: CondWidth, IsSigned: CondIsSigned);
1620	if (EI->first <= Hi)
1621	break;
1622	}
1623
1624	if (RI == CaseRanges.end() || EI->first < RI->first) {
1625	hasCasesNotInSwitch = true;
1626	UnhandledNames.push_back(Elt: EI->second->getDeclName());
1627	}
1628	}
1629
1630	if (TheDefaultStmt && UnhandledNames.empty() && ED->isClosedNonFlag())
1631	Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
1632
1633	// Produce a nice diagnostic if multiple values aren't handled.
1634	if (!UnhandledNames.empty()) {
1635	auto DB = Diag(CondExpr->getExprLoc(), TheDefaultStmt
1636	? diag::warn_def_missing_case
1637	: diag::warn_missing_case)
1638	<< CondExpr->getSourceRange() << (int)UnhandledNames.size();
1639
1640	for (size_t I = 0, E = std::min(a: UnhandledNames.size(), b: (size_t)3);
1641	I != E; ++I)
1642	DB << UnhandledNames[I];
1643	}
1644
1645	if (!hasCasesNotInSwitch)
1646	SS->setAllEnumCasesCovered();
1647	}
1648	}
1649
1650	if (BodyStmt)
1651	DiagnoseEmptyStmtBody(CondExpr->getEndLoc(), BodyStmt,
1652	diag::warn_empty_switch_body);
1653
1654	// FIXME: If the case list was broken is some way, we don't have a good system
1655	// to patch it up. Instead, just return the whole substmt as broken.
1656	if (CaseListIsErroneous)
1657	return StmtError();
1658
1659	return SS;
1660	}
1661
1662	void
1663	Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
1664	Expr *SrcExpr) {
1665	if (Diags.isIgnored(diag::warn_not_in_enum_assignment, SrcExpr->getExprLoc()))
1666	return;
1667
1668	if (const EnumType *ET = DstType->getAs<EnumType>())
1669	if (!Context.hasSameUnqualifiedType(T1: SrcType, T2: DstType) &&
1670	SrcType->isIntegerType()) {
1671	if (!SrcExpr->isTypeDependent() && !SrcExpr->isValueDependent() &&
1672	SrcExpr->isIntegerConstantExpr(Ctx: Context)) {
1673	// Get the bitwidth of the enum value before promotions.
1674	unsigned DstWidth = Context.getIntWidth(T: DstType);
1675	bool DstIsSigned = DstType->isSignedIntegerOrEnumerationType();
1676
1677	llvm::APSInt RhsVal = SrcExpr->EvaluateKnownConstInt(Ctx: Context);
1678	AdjustAPSInt(Val&: RhsVal, BitWidth: DstWidth, IsSigned: DstIsSigned);
1679	const EnumDecl *ED = ET->getDecl();
1680
1681	if (!ED->isClosed())
1682	return;
1683
1684	if (ED->hasAttr<FlagEnumAttr>()) {
1685	if (!IsValueInFlagEnum(ED, RhsVal, true))
1686	Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1687	<< DstType.getUnqualifiedType();
1688	} else {
1689	typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl *>, 64>
1690	EnumValsTy;
1691	EnumValsTy EnumVals;
1692
1693	// Gather all enum values, set their type and sort them,
1694	// allowing easier comparison with rhs constant.
1695	for (auto *EDI : ED->enumerators()) {
1696	llvm::APSInt Val = EDI->getInitVal();
1697	AdjustAPSInt(Val, BitWidth: DstWidth, IsSigned: DstIsSigned);
1698	EnumVals.push_back(Elt: std::make_pair(x&: Val, y&: EDI));
1699	}
1700	if (EnumVals.empty())
1701	return;
1702	llvm::stable_sort(Range&: EnumVals, C: CmpEnumVals);
1703	EnumValsTy::iterator EIend =
1704	std::unique(first: EnumVals.begin(), last: EnumVals.end(), binary_pred: EqEnumVals);
1705
1706	// See which values aren't in the enum.
1707	EnumValsTy::const_iterator EI = EnumVals.begin();
1708	while (EI != EIend && EI->first < RhsVal)
1709	EI++;
1710	if (EI == EIend || EI->first != RhsVal) {
1711	Diag(SrcExpr->getExprLoc(), diag::warn_not_in_enum_assignment)
1712	<< DstType.getUnqualifiedType();
1713	}
1714	}
1715	}
1716	}
1717	}
1718
1719	StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc,
1720	SourceLocation LParenLoc, ConditionResult Cond,
1721	SourceLocation RParenLoc, Stmt *Body) {
1722	if (Cond.isInvalid())
1723	return StmtError();
1724
1725	auto CondVal = Cond.get();
1726	CheckBreakContinueBinding(E: CondVal.second);
1727
1728	if (CondVal.second &&
1729	!Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
1730	CommaVisitor(*this).Visit(CondVal.second);
1731
1732	if (isa<NullStmt>(Val: Body))
1733	getCurCompoundScope().setHasEmptyLoopBodies();
1734
1735	return WhileStmt::Create(Ctx: Context, Var: CondVal.first, Cond: CondVal.second, Body,
1736	WL: WhileLoc, LParenLoc, RParenLoc);
1737	}
1738
1739	StmtResult
1740	Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
1741	SourceLocation WhileLoc, SourceLocation CondLParen,
1742	Expr *Cond, SourceLocation CondRParen) {
1743	assert(Cond && "ActOnDoStmt(): missing expression");
1744
1745	CheckBreakContinueBinding(E: Cond);
1746	ExprResult CondResult = CheckBooleanCondition(Loc: DoLoc, E: Cond);
1747	if (CondResult.isInvalid())
1748	return StmtError();
1749	Cond = CondResult.get();
1750
1751	CondResult = ActOnFinishFullExpr(Expr: Cond, CC: DoLoc, /*DiscardedValue*/ false);
1752	if (CondResult.isInvalid())
1753	return StmtError();
1754	Cond = CondResult.get();
1755
1756	// Only call the CommaVisitor for C89 due to differences in scope flags.
1757	if (Cond && !getLangOpts().C99 && !getLangOpts().CPlusPlus &&
1758	!Diags.isIgnored(diag::warn_comma_operator, Cond->getExprLoc()))
1759	CommaVisitor(*this).Visit(Cond);
1760
1761	return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
1762	}
1763
1764	namespace {
1765	// Use SetVector since the diagnostic cares about the ordering of the Decl's.
1766	using DeclSetVector = llvm::SmallSetVector<VarDecl *, 8>;
1767
1768	// This visitor will traverse a conditional statement and store all
1769	// the evaluated decls into a vector. Simple is set to true if none
1770	// of the excluded constructs are used.
1771	class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> {
1772	DeclSetVector &Decls;
1773	SmallVectorImpl<SourceRange> &Ranges;
1774	bool Simple;
1775	public:
1776	typedef EvaluatedExprVisitor<DeclExtractor> Inherited;
1777
1778	DeclExtractor(Sema &S, DeclSetVector &Decls,
1779	SmallVectorImpl<SourceRange> &Ranges) :
1780	Inherited(S.Context),
1781	Decls(Decls),
1782	Ranges(Ranges),
1783	Simple(true) {}
1784
1785	bool isSimple() { return Simple; }
1786
1787	// Replaces the method in EvaluatedExprVisitor.
1788	void VisitMemberExpr(MemberExpr* E) {
1789	Simple = false;
1790	}
1791
1792	// Any Stmt not explicitly listed will cause the condition to be marked
1793	// complex.
1794	void VisitStmt(Stmt *S) { Simple = false; }
1795
1796	void VisitBinaryOperator(BinaryOperator *E) {
1797	Visit(E->getLHS());
1798	Visit(E->getRHS());
1799	}
1800
1801	void VisitCastExpr(CastExpr *E) {
1802	Visit(E->getSubExpr());
1803	}
1804
1805	void VisitUnaryOperator(UnaryOperator *E) {
1806	// Skip checking conditionals with derefernces.
1807	if (E->getOpcode() == UO_Deref)
1808	Simple = false;
1809	else
1810	Visit(E->getSubExpr());
1811	}
1812
1813	void VisitConditionalOperator(ConditionalOperator *E) {
1814	Visit(E->getCond());
1815	Visit(E->getTrueExpr());
1816	Visit(E->getFalseExpr());
1817	}
1818
1819	void VisitParenExpr(ParenExpr *E) {
1820	Visit(E->getSubExpr());
1821	}
1822
1823	void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) {
1824	Visit(E->getOpaqueValue()->getSourceExpr());
1825	Visit(E->getFalseExpr());
1826	}
1827
1828	void VisitIntegerLiteral(IntegerLiteral *E) { }
1829	void VisitFloatingLiteral(FloatingLiteral *E) { }
1830	void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { }
1831	void VisitCharacterLiteral(CharacterLiteral *E) { }
1832	void VisitGNUNullExpr(GNUNullExpr *E) { }
1833	void VisitImaginaryLiteral(ImaginaryLiteral *E) { }
1834
1835	void VisitDeclRefExpr(DeclRefExpr *E) {
1836	VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl());
1837	if (!VD) {
1838	// Don't allow unhandled Decl types.
1839	Simple = false;
1840	return;
1841	}
1842
1843	Ranges.push_back(Elt: E->getSourceRange());
1844
1845	Decls.insert(X: VD);
1846	}
1847
1848	}; // end class DeclExtractor
1849
1850	// DeclMatcher checks to see if the decls are used in a non-evaluated
1851	// context.
1852	class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> {
1853	DeclSetVector &Decls;
1854	bool FoundDecl;
1855
1856	public:
1857	typedef EvaluatedExprVisitor<DeclMatcher> Inherited;
1858
1859	DeclMatcher(Sema &S, DeclSetVector &Decls, Stmt *Statement) :
1860	Inherited(S.Context), Decls(Decls), FoundDecl(false) {
1861	if (!Statement) return;
1862
1863	Visit(S: Statement);
1864	}
1865
1866	void VisitReturnStmt(ReturnStmt *S) {
1867	FoundDecl = true;
1868	}
1869
1870	void VisitBreakStmt(BreakStmt *S) {
1871	FoundDecl = true;
1872	}
1873
1874	void VisitGotoStmt(GotoStmt *S) {
1875	FoundDecl = true;
1876	}
1877
1878	void VisitCastExpr(CastExpr *E) {
1879	if (E->getCastKind() == CK_LValueToRValue)
1880	CheckLValueToRValueCast(E: E->getSubExpr());
1881	else
1882	Visit(E->getSubExpr());
1883	}
1884
1885	void CheckLValueToRValueCast(Expr *E) {
1886	E = E->IgnoreParenImpCasts();
1887
1888	if (isa<DeclRefExpr>(Val: E)) {
1889	return;
1890	}
1891
1892	if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(Val: E)) {
1893	Visit(CO->getCond());
1894	CheckLValueToRValueCast(E: CO->getTrueExpr());
1895	CheckLValueToRValueCast(E: CO->getFalseExpr());
1896	return;
1897	}
1898
1899	if (BinaryConditionalOperator *BCO =
1900	dyn_cast<BinaryConditionalOperator>(Val: E)) {
1901	CheckLValueToRValueCast(E: BCO->getOpaqueValue()->getSourceExpr());
1902	CheckLValueToRValueCast(E: BCO->getFalseExpr());
1903	return;
1904	}
1905
1906	Visit(E);
1907	}
1908
1909	void VisitDeclRefExpr(DeclRefExpr *E) {
1910	if (VarDecl *VD = dyn_cast<VarDecl>(Val: E->getDecl()))
1911	if (Decls.count(key: VD))
1912	FoundDecl = true;
1913	}
1914
1915	void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
1916	// Only need to visit the semantics for POE.
1917	// SyntaticForm doesn't really use the Decal.
1918	for (auto *S : POE->semantics()) {
1919	if (auto *OVE = dyn_cast<OpaqueValueExpr>(Val: S))
1920	// Look past the OVE into the expression it binds.
1921	Visit(OVE->getSourceExpr());
1922	else
1923	Visit(S);
1924	}
1925	}
1926
1927	bool FoundDeclInUse() { return FoundDecl; }
1928
1929	}; // end class DeclMatcher
1930
1931	void CheckForLoopConditionalStatement(Sema &S, Expr *Second,
1932	Expr *Third, Stmt *Body) {
1933	// Condition is empty
1934	if (!Second) return;
1935
1936	if (S.Diags.isIgnored(diag::warn_variables_not_in_loop_body,
1937	Second->getBeginLoc()))
1938	return;
1939
1940	PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body);
1941	DeclSetVector Decls;
1942	SmallVector<SourceRange, 10> Ranges;
1943	DeclExtractor DE(S, Decls, Ranges);
1944	DE.Visit(Second);
1945
1946	// Don't analyze complex conditionals.
1947	if (!DE.isSimple()) return;
1948
1949	// No decls found.
1950	if (Decls.size() == 0) return;
1951
1952	// Don't warn on volatile, static, or global variables.
1953	for (auto *VD : Decls)
1954	if (VD->getType().isVolatileQualified() || VD->hasGlobalStorage())
1955	return;
1956
1957	if (DeclMatcher(S, Decls, Second).FoundDeclInUse() ||
1958	DeclMatcher(S, Decls, Third).FoundDeclInUse() ||
1959	DeclMatcher(S, Decls, Body).FoundDeclInUse())
1960	return;
1961
1962	// Load decl names into diagnostic.
1963	if (Decls.size() > 4) {
1964	PDiag << 0;
1965	} else {
1966	PDiag << (unsigned)Decls.size();
1967	for (auto *VD : Decls)
1968	PDiag << VD->getDeclName();
1969	}
1970
1971	for (auto Range : Ranges)
1972	PDiag << Range;
1973
1974	S.Diag(Ranges.begin()->getBegin(), PDiag);
1975	}
1976
1977	// If Statement is an incemement or decrement, return true and sets the
1978	// variables Increment and DRE.
1979	bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
1980	DeclRefExpr *&DRE) {
1981	if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: Statement))
1982	if (!Cleanups->cleanupsHaveSideEffects())
1983	Statement = Cleanups->getSubExpr();
1984
1985	if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Val: Statement)) {
1986	switch (UO->getOpcode()) {
1987	default: return false;
1988	case UO_PostInc:
1989	case UO_PreInc:
1990	Increment = true;
1991	break;
1992	case UO_PostDec:
1993	case UO_PreDec:
1994	Increment = false;
1995	break;
1996	}
1997	DRE = dyn_cast<DeclRefExpr>(Val: UO->getSubExpr());
1998	return DRE;
1999	}
2000
2001	if (CXXOperatorCallExpr *Call = dyn_cast<CXXOperatorCallExpr>(Val: Statement)) {
2002	FunctionDecl *FD = Call->getDirectCallee();
2003	if (!FD || !FD->isOverloadedOperator()) return false;
2004	switch (FD->getOverloadedOperator()) {
2005	default: return false;
2006	case OO_PlusPlus:
2007	Increment = true;
2008	break;
2009	case OO_MinusMinus:
2010	Increment = false;
2011	break;
2012	}
2013	DRE = dyn_cast<DeclRefExpr>(Call->getArg(0));
2014	return DRE;
2015	}
2016
2017	return false;
2018	}
2019
2020	// A visitor to determine if a continue or break statement is a
2021	// subexpression.
2022	class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
2023	SourceLocation BreakLoc;
2024	SourceLocation ContinueLoc;
2025	bool InSwitch = false;
2026
2027	public:
2028	BreakContinueFinder(Sema &S, const Stmt* Body) :
2029	Inherited(S.Context) {
2030	Visit(S: Body);
2031	}
2032
2033	typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
2034
2035	void VisitContinueStmt(const ContinueStmt* E) {
2036	ContinueLoc = E->getContinueLoc();
2037	}
2038
2039	void VisitBreakStmt(const BreakStmt* E) {
2040	if (!InSwitch)
2041	BreakLoc = E->getBreakLoc();
2042	}
2043
2044	void VisitSwitchStmt(const SwitchStmt* S) {
2045	if (const Stmt *Init = S->getInit())
2046	Visit(S: Init);
2047	if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
2048	Visit(S: CondVar);
2049	if (const Stmt *Cond = S->getCond())
2050	Visit(S: Cond);
2051
2052	// Don't return break statements from the body of a switch.
2053	InSwitch = true;
2054	if (const Stmt *Body = S->getBody())
2055	Visit(S: Body);
2056	InSwitch = false;
2057	}
2058
2059	void VisitForStmt(const ForStmt *S) {
2060	// Only visit the init statement of a for loop; the body
2061	// has a different break/continue scope.
2062	if (const Stmt *Init = S->getInit())
2063	Visit(S: Init);
2064	}
2065
2066	void VisitWhileStmt(const WhileStmt *) {
2067	// Do nothing; the children of a while loop have a different
2068	// break/continue scope.
2069	}
2070
2071	void VisitDoStmt(const DoStmt *) {
2072	// Do nothing; the children of a while loop have a different
2073	// break/continue scope.
2074	}
2075
2076	void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
2077	// Only visit the initialization of a for loop; the body
2078	// has a different break/continue scope.
2079	if (const Stmt *Init = S->getInit())
2080	Visit(S: Init);
2081	if (const Stmt *Range = S->getRangeStmt())
2082	Visit(S: Range);
2083	if (const Stmt *Begin = S->getBeginStmt())
2084	Visit(S: Begin);
2085	if (const Stmt *End = S->getEndStmt())
2086	Visit(S: End);
2087	}
2088
2089	void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
2090	// Only visit the initialization of a for loop; the body
2091	// has a different break/continue scope.
2092	if (const Stmt *Element = S->getElement())
2093	Visit(S: Element);
2094	if (const Stmt *Collection = S->getCollection())
2095	Visit(S: Collection);
2096	}
2097
2098	bool ContinueFound() { return ContinueLoc.isValid(); }
2099	bool BreakFound() { return BreakLoc.isValid(); }
2100	SourceLocation GetContinueLoc() { return ContinueLoc; }
2101	SourceLocation GetBreakLoc() { return BreakLoc; }
2102
2103	}; // end class BreakContinueFinder
2104
2105	// Emit a warning when a loop increment/decrement appears twice per loop
2106	// iteration. The conditions which trigger this warning are:
2107	// 1) The last statement in the loop body and the third expression in the
2108	// for loop are both increment or both decrement of the same variable
2109	// 2) No continue statements in the loop body.
2110	void CheckForRedundantIteration(Sema &S, Expr *Third, Stmt *Body) {
2111	// Return when there is nothing to check.
2112	if (!Body || !Third) return;
2113
2114	if (S.Diags.isIgnored(diag::warn_redundant_loop_iteration,
2115	Third->getBeginLoc()))
2116	return;
2117
2118	// Get the last statement from the loop body.
2119	CompoundStmt *CS = dyn_cast<CompoundStmt>(Val: Body);
2120	if (!CS || CS->body_empty()) return;
2121	Stmt *LastStmt = CS->body_back();
2122	if (!LastStmt) return;
2123
2124	bool LoopIncrement, LastIncrement;
2125	DeclRefExpr *LoopDRE, *LastDRE;
2126
2127	if (!ProcessIterationStmt(S, Third, LoopIncrement, LoopDRE)) return;
2128	if (!ProcessIterationStmt(S, Statement: LastStmt, Increment&: LastIncrement, DRE&: LastDRE)) return;
2129
2130	// Check that the two statements are both increments or both decrements
2131	// on the same variable.
2132	if (LoopIncrement != LastIncrement ||
2133	LoopDRE->getDecl() != LastDRE->getDecl()) return;
2134
2135	if (BreakContinueFinder(S, Body).ContinueFound()) return;
2136
2137	S.Diag(LastDRE->getLocation(), diag::warn_redundant_loop_iteration)
2138	<< LastDRE->getDecl() << LastIncrement;
2139	S.Diag(LoopDRE->getLocation(), diag::note_loop_iteration_here)
2140	<< LoopIncrement;
2141	}
2142
2143	} // end namespace
2144
2145
2146	void Sema::CheckBreakContinueBinding(Expr *E) {
2147	if (!E || getLangOpts().CPlusPlus)
2148	return;
2149	BreakContinueFinder BCFinder(*this, E);
2150	Scope *BreakParent = CurScope->getBreakParent();
2151	if (BCFinder.BreakFound() && BreakParent) {
2152	if (BreakParent->getFlags() & Scope::SwitchScope) {
2153	Diag(BCFinder.GetBreakLoc(), diag::warn_break_binds_to_switch);
2154	} else {
2155	Diag(BCFinder.GetBreakLoc(), diag::warn_loop_ctrl_binds_to_inner)
2156	<< "break";
2157	}
2158	} else if (BCFinder.ContinueFound() && CurScope->getContinueParent()) {
2159	Diag(BCFinder.GetContinueLoc(), diag::warn_loop_ctrl_binds_to_inner)
2160	<< "continue";
2161	}
2162	}
2163
2164	StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
2165	Stmt *First, ConditionResult Second,
2166	FullExprArg third, SourceLocation RParenLoc,
2167	Stmt *Body) {
2168	if (Second.isInvalid())
2169	return StmtError();
2170
2171	if (!getLangOpts().CPlusPlus) {
2172	if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(Val: First)) {
2173	// C99 6.8.5p3: The declaration part of a 'for' statement shall only
2174	// declare identifiers for objects having storage class 'auto' or
2175	// 'register'.
2176	const Decl *NonVarSeen = nullptr;
2177	bool VarDeclSeen = false;
2178	for (auto *DI : DS->decls()) {
2179	if (VarDecl *VD = dyn_cast<VarDecl>(Val: DI)) {
2180	VarDeclSeen = true;
2181	if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) {
2182	Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
2183	DI->setInvalidDecl();
2184	}
2185	} else if (!NonVarSeen) {
2186	// Keep track of the first non-variable declaration we saw so that
2187	// we can diagnose if we don't see any variable declarations. This
2188	// covers a case like declaring a typedef, function, or structure
2189	// type rather than a variable.
2190	NonVarSeen = DI;
2191	}
2192	}
2193	// Diagnose if we saw a non-variable declaration but no variable
2194	// declarations.
2195	if (NonVarSeen && !VarDeclSeen)
2196	Diag(NonVarSeen->getLocation(), diag::err_non_variable_decl_in_for);
2197	}
2198	}
2199
2200	CheckBreakContinueBinding(E: Second.get().second);
2201	CheckBreakContinueBinding(E: third.get());
2202
2203	if (!Second.get().first)
2204	CheckForLoopConditionalStatement(S&: *this, Second: Second.get().second, Third: third.get(),
2205	Body);
2206	CheckForRedundantIteration(S&: *this, Third: third.get(), Body);
2207
2208	if (Second.get().second &&
2209	!Diags.isIgnored(diag::warn_comma_operator,
2210	Second.get().second->getExprLoc()))
2211	CommaVisitor(*this).Visit(Second.get().second);
2212
2213	Expr *Third = third.release().getAs<Expr>();
2214	if (isa<NullStmt>(Val: Body))
2215	getCurCompoundScope().setHasEmptyLoopBodies();
2216
2217	return new (Context)
2218	ForStmt(Context, First, Second.get().second, Second.get().first, Third,
2219	Body, ForLoc, LParenLoc, RParenLoc);
2220	}
2221
2222	/// In an Objective C collection iteration statement:
2223	/// for (x in y)
2224	/// x can be an arbitrary l-value expression. Bind it up as a
2225	/// full-expression.
2226	StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
2227	// Reduce placeholder expressions here. Note that this rejects the
2228	// use of pseudo-object l-values in this position.
2229	ExprResult result = CheckPlaceholderExpr(E);
2230	if (result.isInvalid()) return StmtError();
2231	E = result.get();
2232
2233	ExprResult FullExpr = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
2234	if (FullExpr.isInvalid())
2235	return StmtError();
2236	return StmtResult(static_cast<Stmt*>(FullExpr.get()));
2237	}
2238
2239	ExprResult
2240	Sema::CheckObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) {
2241	if (!collection)
2242	return ExprError();
2243
2244	ExprResult result = CorrectDelayedTyposInExpr(E: collection);
2245	if (!result.isUsable())
2246	return ExprError();
2247	collection = result.get();
2248
2249	// Bail out early if we've got a type-dependent expression.
2250	if (collection->isTypeDependent()) return collection;
2251
2252	// Perform normal l-value conversion.
2253	result = DefaultFunctionArrayLvalueConversion(E: collection);
2254	if (result.isInvalid())
2255	return ExprError();
2256	collection = result.get();
2257
2258	// The operand needs to have object-pointer type.
2259	// TODO: should we do a contextual conversion?
2260	const ObjCObjectPointerType *pointerType =
2261	collection->getType()->getAs<ObjCObjectPointerType>();
2262	if (!pointerType)
2263	return Diag(forLoc, diag::err_collection_expr_type)
2264	<< collection->getType() << collection->getSourceRange();
2265
2266	// Check that the operand provides
2267	// - countByEnumeratingWithState:objects:count:
2268	const ObjCObjectType *objectType = pointerType->getObjectType();
2269	ObjCInterfaceDecl *iface = objectType->getInterface();
2270
2271	// If we have a forward-declared type, we can't do this check.
2272	// Under ARC, it is an error not to have a forward-declared class.
2273	if (iface &&
2274	(getLangOpts().ObjCAutoRefCount
2275	? RequireCompleteType(forLoc, QualType(objectType, 0),
2276	diag::err_arc_collection_forward, collection)
2277	: !isCompleteType(forLoc, QualType(objectType, 0)))) {
2278	// Otherwise, if we have any useful type information, check that
2279	// the type declares the appropriate method.
2280	} else if (iface || !objectType->qual_empty()) {
2281	const IdentifierInfo *selectorIdents[] = {
2282	&Context.Idents.get(Name: "countByEnumeratingWithState"),
2283	&Context.Idents.get(Name: "objects"), &Context.Idents.get(Name: "count")};
2284	Selector selector = Context.Selectors.getSelector(NumArgs: 3, IIV: &selectorIdents[0]);
2285
2286	ObjCMethodDecl *method = nullptr;
2287
2288	// If there's an interface, look in both the public and private APIs.
2289	if (iface) {
2290	method = iface->lookupInstanceMethod(Sel: selector);
2291	if (!method) method = iface->lookupPrivateMethod(Sel: selector);
2292	}
2293
2294	// Also check protocol qualifiers.
2295	if (!method)
2296	method = LookupMethodInQualifiedType(Sel: selector, OPT: pointerType,
2297	/*instance*/ IsInstance: true);
2298
2299	// If we didn't find it anywhere, give up.
2300	if (!method) {
2301	Diag(forLoc, diag::warn_collection_expr_type)
2302	<< collection->getType() << selector << collection->getSourceRange();
2303	}
2304
2305	// TODO: check for an incompatible signature?
2306	}
2307
2308	// Wrap up any cleanups in the expression.
2309	return collection;
2310	}
2311
2312	StmtResult
2313	Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
2314	Stmt *First, Expr *collection,
2315	SourceLocation RParenLoc) {
2316	setFunctionHasBranchProtectedScope();
2317
2318	ExprResult CollectionExprResult =
2319	CheckObjCForCollectionOperand(forLoc: ForLoc, collection);
2320
2321	if (First) {
2322	QualType FirstType;
2323	if (DeclStmt *DS = dyn_cast<DeclStmt>(Val: First)) {
2324	if (!DS->isSingleDecl())
2325	return StmtError(Diag((*DS->decl_begin())->getLocation(),
2326	diag::err_toomany_element_decls));
2327
2328	VarDecl *D = dyn_cast<VarDecl>(Val: DS->getSingleDecl());
2329	if (!D || D->isInvalidDecl())
2330	return StmtError();
2331
2332	FirstType = D->getType();
2333	// C99 6.8.5p3: The declaration part of a 'for' statement shall only
2334	// declare identifiers for objects having storage class 'auto' or
2335	// 'register'.
2336	if (!D->hasLocalStorage())
2337	return StmtError(Diag(D->getLocation(),
2338	diag::err_non_local_variable_decl_in_for));
2339
2340	// If the type contained 'auto', deduce the 'auto' to 'id'.
2341	if (FirstType->getContainedAutoType()) {
2342	SourceLocation Loc = D->getLocation();
2343	OpaqueValueExpr OpaqueId(Loc, Context.getObjCIdType(), VK_PRValue);
2344	Expr *DeducedInit = &OpaqueId;
2345	TemplateDeductionInfo Info(Loc);
2346	FirstType = QualType();
2347	TemplateDeductionResult Result = DeduceAutoType(
2348	AutoTypeLoc: D->getTypeSourceInfo()->getTypeLoc(), Initializer: DeducedInit, Result&: FirstType, Info);
2349	if (Result != TemplateDeductionResult::Success &&
2350	Result != TemplateDeductionResult::AlreadyDiagnosed)
2351	DiagnoseAutoDeductionFailure(VDecl: D, Init: DeducedInit);
2352	if (FirstType.isNull()) {
2353	D->setInvalidDecl();
2354	return StmtError();
2355	}
2356
2357	D->setType(FirstType);
2358
2359	if (!inTemplateInstantiation()) {
2360	SourceLocation Loc =
2361	D->getTypeSourceInfo()->getTypeLoc().getBeginLoc();
2362	Diag(Loc, diag::warn_auto_var_is_id)
2363	<< D->getDeclName();
2364	}
2365	}
2366
2367	} else {
2368	Expr *FirstE = cast<Expr>(Val: First);
2369	if (!FirstE->isTypeDependent() && !FirstE->isLValue())
2370	return StmtError(
2371	Diag(First->getBeginLoc(), diag::err_selector_element_not_lvalue)
2372	<< First->getSourceRange());
2373
2374	FirstType = static_cast<Expr*>(First)->getType();
2375	if (FirstType.isConstQualified())
2376	Diag(ForLoc, diag::err_selector_element_const_type)
2377	<< FirstType << First->getSourceRange();
2378	}
2379	if (!FirstType->isDependentType() &&
2380	!FirstType->isObjCObjectPointerType() &&
2381	!FirstType->isBlockPointerType())
2382	return StmtError(Diag(ForLoc, diag::err_selector_element_type)
2383	<< FirstType << First->getSourceRange());
2384	}
2385
2386	if (CollectionExprResult.isInvalid())
2387	return StmtError();
2388
2389	CollectionExprResult =
2390	ActOnFinishFullExpr(Expr: CollectionExprResult.get(), /*DiscardedValue*/ false);
2391	if (CollectionExprResult.isInvalid())
2392	return StmtError();
2393
2394	return new (Context) ObjCForCollectionStmt(First, CollectionExprResult.get(),
2395	nullptr, ForLoc, RParenLoc);
2396	}
2397
2398	/// Finish building a variable declaration for a for-range statement.
2399	/// \return true if an error occurs.
2400	static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
2401	SourceLocation Loc, int DiagID) {
2402	if (Decl->getType()->isUndeducedType()) {
2403	ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(E: Init);
2404	if (!Res.isUsable()) {
2405	Decl->setInvalidDecl();
2406	return true;
2407	}
2408	Init = Res.get();
2409	}
2410
2411	// Deduce the type for the iterator variable now rather than leaving it to
2412	// AddInitializerToDecl, so we can produce a more suitable diagnostic.
2413	QualType InitType;
2414	if (!isa<InitListExpr>(Val: Init) && Init->getType()->isVoidType()) {
2415	SemaRef.Diag(Loc, DiagID) << Init->getType();
2416	} else {
2417	TemplateDeductionInfo Info(Init->getExprLoc());
2418	TemplateDeductionResult Result = SemaRef.DeduceAutoType(
2419	AutoTypeLoc: Decl->getTypeSourceInfo()->getTypeLoc(), Initializer: Init, Result&: InitType, Info);
2420	if (Result != TemplateDeductionResult::Success &&
2421	Result != TemplateDeductionResult::AlreadyDiagnosed)
2422	SemaRef.Diag(Loc, DiagID) << Init->getType();
2423	}
2424
2425	if (InitType.isNull()) {
2426	Decl->setInvalidDecl();
2427	return true;
2428	}
2429	Decl->setType(InitType);
2430
2431	// In ARC, infer lifetime.
2432	// FIXME: ARC may want to turn this into 'const __unsafe_unretained' if
2433	// we're doing the equivalent of fast iteration.
2434	if (SemaRef.getLangOpts().ObjCAutoRefCount &&
2435	SemaRef.inferObjCARCLifetime(Decl))
2436	Decl->setInvalidDecl();
2437
2438	SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false);
2439	SemaRef.FinalizeDeclaration(Decl);
2440	SemaRef.CurContext->addHiddenDecl(Decl);
2441	return false;
2442	}
2443
2444	namespace {
2445	// An enum to represent whether something is dealing with a call to begin()
2446	// or a call to end() in a range-based for loop.
2447	enum BeginEndFunction {
2448	BEF_begin,
2449	BEF_end
2450	};
2451
2452	/// Produce a note indicating which begin/end function was implicitly called
2453	/// by a C++11 for-range statement. This is often not obvious from the code,
2454	/// nor from the diagnostics produced when analysing the implicit expressions
2455	/// required in a for-range statement.
2456	void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E,
2457	BeginEndFunction BEF) {
2458	CallExpr *CE = dyn_cast<CallExpr>(Val: E);
2459	if (!CE)
2460	return;
2461	FunctionDecl *D = dyn_cast<FunctionDecl>(Val: CE->getCalleeDecl());
2462	if (!D)
2463	return;
2464	SourceLocation Loc = D->getLocation();
2465
2466	std::string Description;
2467	bool IsTemplate = false;
2468	if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) {
2469	Description = SemaRef.getTemplateArgumentBindingsText(
2470	FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs());
2471	IsTemplate = true;
2472	}
2473
2474	SemaRef.Diag(Loc, diag::note_for_range_begin_end)
2475	<< BEF << IsTemplate << Description << E->getType();
2476	}
2477
2478	/// Build a variable declaration for a for-range statement.
2479	VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc,
2480	QualType Type, StringRef Name) {
2481	DeclContext *DC = SemaRef.CurContext;
2482	IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name);
2483	TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(T: Type, Loc);
2484	VarDecl *Decl = VarDecl::Create(C&: SemaRef.Context, DC, StartLoc: Loc, IdLoc: Loc, Id: II, T: Type,
2485	TInfo, S: SC_None);
2486	Decl->setImplicit();
2487	return Decl;
2488	}
2489
2490	}
2491
2492	static bool ObjCEnumerationCollection(Expr *Collection) {
2493	return !Collection->isTypeDependent()
2494	&& Collection->getType()->getAs<ObjCObjectPointerType>() != nullptr;
2495	}
2496
2497	/// ActOnCXXForRangeStmt - Check and build a C++11 for-range statement.
2498	///
2499	/// C++11 [stmt.ranged]:
2500	/// A range-based for statement is equivalent to
2501	///
2502	/// {
2503	/// auto && __range = range-init;
2504	/// for ( auto __begin = begin-expr,
2505	/// __end = end-expr;
2506	/// __begin != __end;
2507	/// ++__begin ) {
2508	/// for-range-declaration = *__begin;
2509	/// statement
2510	/// }
2511	/// }
2512	///
2513	/// The body of the loop is not available yet, since it cannot be analysed until
2514	/// we have determined the type of the for-range-declaration.
2515	StmtResult Sema::ActOnCXXForRangeStmt(
2516	Scope *S, SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2517	Stmt *First, SourceLocation ColonLoc, Expr *Range, SourceLocation RParenLoc,
2518	BuildForRangeKind Kind,
2519	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2520	// FIXME: recover in order to allow the body to be parsed.
2521	if (!First)
2522	return StmtError();
2523
2524	if (Range && ObjCEnumerationCollection(Collection: Range)) {
2525	// FIXME: Support init-statements in Objective-C++20 ranged for statement.
2526	if (InitStmt)
2527	return Diag(InitStmt->getBeginLoc(), diag::err_objc_for_range_init_stmt)
2528	<< InitStmt->getSourceRange();
2529	return ActOnObjCForCollectionStmt(ForLoc, First, collection: Range, RParenLoc);
2530	}
2531
2532	DeclStmt *DS = dyn_cast<DeclStmt>(Val: First);
2533	assert(DS && "first part of for range not a decl stmt");
2534
2535	if (!DS->isSingleDecl()) {
2536	Diag(DS->getBeginLoc(), diag::err_type_defined_in_for_range);
2537	return StmtError();
2538	}
2539
2540	// This function is responsible for attaching an initializer to LoopVar. We
2541	// must call ActOnInitializerError if we fail to do so.
2542	Decl *LoopVar = DS->getSingleDecl();
2543	if (LoopVar->isInvalidDecl() || !Range ||
2544	DiagnoseUnexpandedParameterPack(E: Range, UPPC: UPPC_Expression)) {
2545	ActOnInitializerError(Dcl: LoopVar);
2546	return StmtError();
2547	}
2548
2549	// Build the coroutine state immediately and not later during template
2550	// instantiation
2551	if (!CoawaitLoc.isInvalid()) {
2552	if (!ActOnCoroutineBodyStart(S, KwLoc: CoawaitLoc, Keyword: "co_await")) {
2553	ActOnInitializerError(Dcl: LoopVar);
2554	return StmtError();
2555	}
2556	}
2557
2558	// Build auto && __range = range-init
2559	// Divide by 2, since the variables are in the inner scope (loop body).
2560	const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2561	SourceLocation RangeLoc = Range->getBeginLoc();
2562	VarDecl *RangeVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: RangeLoc,
2563	Type: Context.getAutoRRefDeductType(),
2564	Name: std::string("__range") + DepthStr);
2565	if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc,
2566	diag::err_for_range_deduction_failure)) {
2567	ActOnInitializerError(Dcl: LoopVar);
2568	return StmtError();
2569	}
2570
2571	// Claim the type doesn't contain auto: we've already done the checking.
2572	DeclGroupPtrTy RangeGroup =
2573	BuildDeclaratorGroup(Group: MutableArrayRef<Decl *>((Decl **)&RangeVar, 1));
2574	StmtResult RangeDecl = ActOnDeclStmt(dg: RangeGroup, StartLoc: RangeLoc, EndLoc: RangeLoc);
2575	if (RangeDecl.isInvalid()) {
2576	ActOnInitializerError(Dcl: LoopVar);
2577	return StmtError();
2578	}
2579
2580	StmtResult R = BuildCXXForRangeStmt(
2581	ForLoc, CoawaitLoc, InitStmt, ColonLoc, RangeDecl: RangeDecl.get(),
2582	/*BeginStmt=*/Begin: nullptr, /*EndStmt=*/End: nullptr,
2583	/*Cond=*/nullptr, /*Inc=*/nullptr, LoopVarDecl: DS, RParenLoc, Kind,
2584	LifetimeExtendTemps);
2585	if (R.isInvalid()) {
2586	ActOnInitializerError(Dcl: LoopVar);
2587	return StmtError();
2588	}
2589
2590	return R;
2591	}
2592
2593	/// Create the initialization, compare, and increment steps for
2594	/// the range-based for loop expression.
2595	/// This function does not handle array-based for loops,
2596	/// which are created in Sema::BuildCXXForRangeStmt.
2597	///
2598	/// \returns a ForRangeStatus indicating success or what kind of error occurred.
2599	/// BeginExpr and EndExpr are set and FRS_Success is returned on success;
2600	/// CandidateSet and BEF are set and some non-success value is returned on
2601	/// failure.
2602	static Sema::ForRangeStatus
2603	BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
2604	QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
2605	SourceLocation ColonLoc, SourceLocation CoawaitLoc,
2606	OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
2607	ExprResult *EndExpr, BeginEndFunction *BEF) {
2608	DeclarationNameInfo BeginNameInfo(
2609	&SemaRef.PP.getIdentifierTable().get(Name: "begin"), ColonLoc);
2610	DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get(Name: "end"),
2611	ColonLoc);
2612
2613	LookupResult BeginMemberLookup(SemaRef, BeginNameInfo,
2614	Sema::LookupMemberName);
2615	LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
2616
2617	auto BuildBegin = [&] {
2618	*BEF = BEF_begin;
2619	Sema::ForRangeStatus RangeStatus =
2620	SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: BeginNameInfo,
2621	MemberLookup&: BeginMemberLookup, CandidateSet,
2622	Range: BeginRange, CallExpr: BeginExpr);
2623
2624	if (RangeStatus != Sema::FRS_Success) {
2625	if (RangeStatus == Sema::FRS_DiagnosticIssued)
2626	SemaRef.Diag(BeginRange->getBeginLoc(), diag::note_in_for_range)
2627	<< ColonLoc << BEF_begin << BeginRange->getType();
2628	return RangeStatus;
2629	}
2630	if (!CoawaitLoc.isInvalid()) {
2631	// FIXME: getCurScope() should not be used during template instantiation.
2632	// We should pick up the set of unqualified lookup results for operator
2633	// co_await during the initial parse.
2634	*BeginExpr = SemaRef.ActOnCoawaitExpr(S: SemaRef.getCurScope(), KwLoc: ColonLoc,
2635	E: BeginExpr->get());
2636	if (BeginExpr->isInvalid())
2637	return Sema::FRS_DiagnosticIssued;
2638	}
2639	if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
2640	diag::err_for_range_iter_deduction_failure)) {
2641	NoteForRangeBeginEndFunction(SemaRef, E: BeginExpr->get(), BEF: *BEF);
2642	return Sema::FRS_DiagnosticIssued;
2643	}
2644	return Sema::FRS_Success;
2645	};
2646
2647	auto BuildEnd = [&] {
2648	*BEF = BEF_end;
2649	Sema::ForRangeStatus RangeStatus =
2650	SemaRef.BuildForRangeBeginEndCall(Loc: ColonLoc, RangeLoc: ColonLoc, NameInfo: EndNameInfo,
2651	MemberLookup&: EndMemberLookup, CandidateSet,
2652	Range: EndRange, CallExpr: EndExpr);
2653	if (RangeStatus != Sema::FRS_Success) {
2654	if (RangeStatus == Sema::FRS_DiagnosticIssued)
2655	SemaRef.Diag(EndRange->getBeginLoc(), diag::note_in_for_range)
2656	<< ColonLoc << BEF_end << EndRange->getType();
2657	return RangeStatus;
2658	}
2659	if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
2660	diag::err_for_range_iter_deduction_failure)) {
2661	NoteForRangeBeginEndFunction(SemaRef, E: EndExpr->get(), BEF: *BEF);
2662	return Sema::FRS_DiagnosticIssued;
2663	}
2664	return Sema::FRS_Success;
2665	};
2666
2667	if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
2668	// - if _RangeT is a class type, the unqualified-ids begin and end are
2669	// looked up in the scope of class _RangeT as if by class member access
2670	// lookup (3.4.5), and if either (or both) finds at least one
2671	// declaration, begin-expr and end-expr are __range.begin() and
2672	// __range.end(), respectively;
2673	SemaRef.LookupQualifiedName(BeginMemberLookup, D);
2674	if (BeginMemberLookup.isAmbiguous())
2675	return Sema::FRS_DiagnosticIssued;
2676
2677	SemaRef.LookupQualifiedName(EndMemberLookup, D);
2678	if (EndMemberLookup.isAmbiguous())
2679	return Sema::FRS_DiagnosticIssued;
2680
2681	if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
2682	// Look up the non-member form of the member we didn't find, first.
2683	// This way we prefer a "no viable 'end'" diagnostic over a "i found
2684	// a 'begin' but ignored it because there was no member 'end'"
2685	// diagnostic.
2686	auto BuildNonmember = [&](
2687	BeginEndFunction BEFFound, LookupResult &Found,
2688	llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
2689	llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
2690	LookupResult OldFound = std::move(Found);
2691	Found.clear();
2692
2693	if (Sema::ForRangeStatus Result = BuildNotFound())
2694	return Result;
2695
2696	switch (BuildFound()) {
2697	case Sema::FRS_Success:
2698	return Sema::FRS_Success;
2699
2700	case Sema::FRS_NoViableFunction:
2701	CandidateSet->NoteCandidates(
2702	PartialDiagnosticAt(BeginRange->getBeginLoc(),
2703	SemaRef.PDiag(diag::err_for_range_invalid)
2704	<< BeginRange->getType() << BEFFound),
2705	SemaRef, OCD_AllCandidates, BeginRange);
2706	[[fallthrough]];
2707
2708	case Sema::FRS_DiagnosticIssued:
2709	for (NamedDecl *D : OldFound) {
2710	SemaRef.Diag(D->getLocation(),
2711	diag::note_for_range_member_begin_end_ignored)
2712	<< BeginRange->getType() << BEFFound;
2713	}
2714	return Sema::FRS_DiagnosticIssued;
2715	}
2716	llvm_unreachable("unexpected ForRangeStatus");
2717	};
2718	if (BeginMemberLookup.empty())
2719	return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
2720	return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin, BuildEnd);
2721	}
2722	} else {
2723	// - otherwise, begin-expr and end-expr are begin(__range) and
2724	// end(__range), respectively, where begin and end are looked up with
2725	// argument-dependent lookup (3.4.2). For the purposes of this name
2726	// lookup, namespace std is an associated namespace.
2727	}
2728
2729	if (Sema::ForRangeStatus Result = BuildBegin())
2730	return Result;
2731	return BuildEnd();
2732	}
2733
2734	/// Speculatively attempt to dereference an invalid range expression.
2735	/// If the attempt fails, this function will return a valid, null StmtResult
2736	/// and emit no diagnostics.
2737	static StmtResult RebuildForRangeWithDereference(Sema &SemaRef, Scope *S,
2738	SourceLocation ForLoc,
2739	SourceLocation CoawaitLoc,
2740	Stmt *InitStmt,
2741	Stmt *LoopVarDecl,
2742	SourceLocation ColonLoc,
2743	Expr *Range,
2744	SourceLocation RangeLoc,
2745	SourceLocation RParenLoc) {
2746	// Determine whether we can rebuild the for-range statement with a
2747	// dereferenced range expression.
2748	ExprResult AdjustedRange;
2749	{
2750	Sema::SFINAETrap Trap(SemaRef);
2751
2752	AdjustedRange = SemaRef.BuildUnaryOp(S, OpLoc: RangeLoc, Opc: UO_Deref, Input: Range);
2753	if (AdjustedRange.isInvalid())
2754	return StmtResult();
2755
2756	StmtResult SR = SemaRef.ActOnCXXForRangeStmt(
2757	S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2758	Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Check);
2759	if (SR.isInvalid())
2760	return StmtResult();
2761	}
2762
2763	// The attempt to dereference worked well enough that it could produce a valid
2764	// loop. Produce a fixit, and rebuild the loop with diagnostics enabled, in
2765	// case there are any other (non-fatal) problems with it.
2766	SemaRef.Diag(RangeLoc, diag::err_for_range_dereference)
2767	<< Range->getType() << FixItHint::CreateInsertion(RangeLoc, "*");
2768	return SemaRef.ActOnCXXForRangeStmt(
2769	S, ForLoc, CoawaitLoc, InitStmt, First: LoopVarDecl, ColonLoc,
2770	Range: AdjustedRange.get(), RParenLoc, Kind: Sema::BFRK_Rebuild);
2771	}
2772
2773	/// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
2774	StmtResult Sema::BuildCXXForRangeStmt(
2775	SourceLocation ForLoc, SourceLocation CoawaitLoc, Stmt *InitStmt,
2776	SourceLocation ColonLoc, Stmt *RangeDecl, Stmt *Begin, Stmt *End,
2777	Expr *Cond, Expr *Inc, Stmt *LoopVarDecl, SourceLocation RParenLoc,
2778	BuildForRangeKind Kind,
2779	ArrayRef<MaterializeTemporaryExpr *> LifetimeExtendTemps) {
2780	// FIXME: This should not be used during template instantiation. We should
2781	// pick up the set of unqualified lookup results for the != and + operators
2782	// in the initial parse.
2783	//
2784	// Testcase (accepts-invalid):
2785	// template<typename T> void f() { for (auto x : T()) {} }
2786	// namespace N { struct X { X begin(); X end(); int operator*(); }; }
2787	// bool operator!=(N::X, N::X); void operator++(N::X);
2788	// void g() { f<N::X>(); }
2789	Scope *S = getCurScope();
2790
2791	DeclStmt *RangeDS = cast<DeclStmt>(Val: RangeDecl);
2792	VarDecl *RangeVar = cast<VarDecl>(Val: RangeDS->getSingleDecl());
2793	QualType RangeVarType = RangeVar->getType();
2794
2795	DeclStmt *LoopVarDS = cast<DeclStmt>(Val: LoopVarDecl);
2796	VarDecl *LoopVar = cast<VarDecl>(Val: LoopVarDS->getSingleDecl());
2797
2798	StmtResult BeginDeclStmt = Begin;
2799	StmtResult EndDeclStmt = End;
2800	ExprResult NotEqExpr = Cond, IncrExpr = Inc;
2801
2802	if (RangeVarType->isDependentType()) {
2803	// The range is implicitly used as a placeholder when it is dependent.
2804	RangeVar->markUsed(Context);
2805
2806	// Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
2807	// them in properly when we instantiate the loop.
2808	if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
2809	if (auto *DD = dyn_cast<DecompositionDecl>(Val: LoopVar))
2810	for (auto *Binding : DD->bindings())
2811	Binding->setType(Context.DependentTy);
2812	LoopVar->setType(SubstAutoTypeDependent(TypeWithAuto: LoopVar->getType()));
2813	}
2814	} else if (!BeginDeclStmt.get()) {
2815	SourceLocation RangeLoc = RangeVar->getLocation();
2816
2817	const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
2818
2819	ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2820	VK_LValue, ColonLoc);
2821	if (BeginRangeRef.isInvalid())
2822	return StmtError();
2823
2824	ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType,
2825	VK_LValue, ColonLoc);
2826	if (EndRangeRef.isInvalid())
2827	return StmtError();
2828
2829	QualType AutoType = Context.getAutoDeductType();
2830	Expr *Range = RangeVar->getInit();
2831	if (!Range)
2832	return StmtError();
2833	QualType RangeType = Range->getType();
2834
2835	if (RequireCompleteType(RangeLoc, RangeType,
2836	diag::err_for_range_incomplete_type))
2837	return StmtError();
2838
2839	// P2718R0 - Lifetime extension in range-based for loops.
2840	if (getLangOpts().CPlusPlus23 && !LifetimeExtendTemps.empty()) {
2841	InitializedEntity Entity =
2842	InitializedEntity::InitializeVariable(Var: RangeVar);
2843	for (auto *MTE : LifetimeExtendTemps)
2844	MTE->setExtendingDecl(RangeVar, Entity.allocateManglingNumber());
2845	}
2846
2847	// Build auto __begin = begin-expr, __end = end-expr.
2848	// Divide by 2, since the variables are in the inner scope (loop body).
2849	const auto DepthStr = std::to_string(val: S->getDepth() / 2);
2850	VarDecl *BeginVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: ColonLoc, Type: AutoType,
2851	Name: std::string("__begin") + DepthStr);
2852	VarDecl *EndVar = BuildForRangeVarDecl(SemaRef&: *this, Loc: ColonLoc, Type: AutoType,
2853	Name: std::string("__end") + DepthStr);
2854
2855	// Build begin-expr and end-expr and attach to __begin and __end variables.
2856	ExprResult BeginExpr, EndExpr;
2857	if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) {
2858	// - if _RangeT is an array type, begin-expr and end-expr are __range and
2859	// __range + __bound, respectively, where __bound is the array bound. If
2860	// _RangeT is an array of unknown size or an array of incomplete type,
2861	// the program is ill-formed;
2862
2863	// begin-expr is __range.
2864	BeginExpr = BeginRangeRef;
2865	if (!CoawaitLoc.isInvalid()) {
2866	BeginExpr = ActOnCoawaitExpr(S, KwLoc: ColonLoc, E: BeginExpr.get());
2867	if (BeginExpr.isInvalid())
2868	return StmtError();
2869	}
2870	if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
2871	diag::err_for_range_iter_deduction_failure)) {
2872	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
2873	return StmtError();
2874	}
2875
2876	// Find the array bound.
2877	ExprResult BoundExpr;
2878	if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Val: UnqAT))
2879	BoundExpr = IntegerLiteral::Create(
2880	C: Context, V: CAT->getSize(), type: Context.getPointerDiffType(), l: RangeLoc);
2881	else if (const VariableArrayType *VAT =
2882	dyn_cast<VariableArrayType>(Val: UnqAT)) {
2883	// For a variably modified type we can't just use the expression within
2884	// the array bounds, since we don't want that to be re-evaluated here.
2885	// Rather, we need to determine what it was when the array was first
2886	// created - so we resort to using sizeof(vla)/sizeof(element).
2887	// For e.g.
2888	// void f(int b) {
2889	// int vla[b];
2890	// b = -1; <-- This should not affect the num of iterations below
2891	// for (int &c : vla) { .. }
2892	// }
2893
2894	// FIXME: This results in codegen generating IR that recalculates the
2895	// run-time number of elements (as opposed to just using the IR Value
2896	// that corresponds to the run-time value of each bound that was
2897	// generated when the array was created.) If this proves too embarrassing
2898	// even for unoptimized IR, consider passing a magic-value/cookie to
2899	// codegen that then knows to simply use that initial llvm::Value (that
2900	// corresponds to the bound at time of array creation) within
2901	// getelementptr. But be prepared to pay the price of increasing a
2902	// customized form of coupling between the two components - which could
2903	// be hard to maintain as the codebase evolves.
2904
2905	ExprResult SizeOfVLAExprR = ActOnUnaryExprOrTypeTraitExpr(
2906	OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2907	/*IsType=*/true,
2908	TyOrEx: CreateParsedType(T: VAT->desugar(), TInfo: Context.getTrivialTypeSourceInfo(
2909	T: VAT->desugar(), Loc: RangeLoc))
2910	.getAsOpaquePtr(),
2911	ArgRange: EndVar->getSourceRange());
2912	if (SizeOfVLAExprR.isInvalid())
2913	return StmtError();
2914
2915	ExprResult SizeOfEachElementExprR = ActOnUnaryExprOrTypeTraitExpr(
2916	OpLoc: EndVar->getLocation(), ExprKind: UETT_SizeOf,
2917	/*IsType=*/true,
2918	TyOrEx: CreateParsedType(T: VAT->desugar(),
2919	TInfo: Context.getTrivialTypeSourceInfo(
2920	T: VAT->getElementType(), Loc: RangeLoc))
2921	.getAsOpaquePtr(),
2922	ArgRange: EndVar->getSourceRange());
2923	if (SizeOfEachElementExprR.isInvalid())
2924	return StmtError();
2925
2926	BoundExpr =
2927	ActOnBinOp(S, TokLoc: EndVar->getLocation(), Kind: tok::slash,
2928	LHSExpr: SizeOfVLAExprR.get(), RHSExpr: SizeOfEachElementExprR.get());
2929	if (BoundExpr.isInvalid())
2930	return StmtError();
2931
2932	} else {
2933	// Can't be a DependentSizedArrayType or an IncompleteArrayType since
2934	// UnqAT is not incomplete and Range is not type-dependent.
2935	llvm_unreachable("Unexpected array type in for-range");
2936	}
2937
2938	// end-expr is __range + __bound.
2939	EndExpr = ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::plus, LHSExpr: EndRangeRef.get(),
2940	RHSExpr: BoundExpr.get());
2941	if (EndExpr.isInvalid())
2942	return StmtError();
2943	if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc,
2944	diag::err_for_range_iter_deduction_failure)) {
2945	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
2946	return StmtError();
2947	}
2948	} else {
2949	OverloadCandidateSet CandidateSet(RangeLoc,
2950	OverloadCandidateSet::CSK_Normal);
2951	BeginEndFunction BEFFailure;
2952	ForRangeStatus RangeStatus = BuildNonArrayForRange(
2953	SemaRef&: *this, BeginRange: BeginRangeRef.get(), EndRange: EndRangeRef.get(), RangeType, BeginVar,
2954	EndVar, ColonLoc, CoawaitLoc, CandidateSet: &CandidateSet, BeginExpr: &BeginExpr, EndExpr: &EndExpr,
2955	BEF: &BEFFailure);
2956
2957	if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
2958	BEFFailure == BEF_begin) {
2959	// If the range is being built from an array parameter, emit a
2960	// a diagnostic that it is being treated as a pointer.
2961	if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Val: Range)) {
2962	if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Val: DRE->getDecl())) {
2963	QualType ArrayTy = PVD->getOriginalType();
2964	QualType PointerTy = PVD->getType();
2965	if (PointerTy->isPointerType() && ArrayTy->isArrayType()) {
2966	Diag(Range->getBeginLoc(), diag::err_range_on_array_parameter)
2967	<< RangeLoc << PVD << ArrayTy << PointerTy;
2968	Diag(PVD->getLocation(), diag::note_declared_at);
2969	return StmtError();
2970	}
2971	}
2972	}
2973
2974	// If building the range failed, try dereferencing the range expression
2975	// unless a diagnostic was issued or the end function is problematic.
2976	StmtResult SR = RebuildForRangeWithDereference(SemaRef&: *this, S, ForLoc,
2977	CoawaitLoc, InitStmt,
2978	LoopVarDecl, ColonLoc,
2979	Range, RangeLoc,
2980	RParenLoc);
2981	if (SR.isInvalid() || SR.isUsable())
2982	return SR;
2983	}
2984
2985	// Otherwise, emit diagnostics if we haven't already.
2986	if (RangeStatus == FRS_NoViableFunction) {
2987	Expr *Range = BEFFailure ? EndRangeRef.get() : BeginRangeRef.get();
2988	CandidateSet.NoteCandidates(
2989	PartialDiagnosticAt(Range->getBeginLoc(),
2990	PDiag(diag::err_for_range_invalid)
2991	<< RangeLoc << Range->getType()
2992	<< BEFFailure),
2993	*this, OCD_AllCandidates, Range);
2994	}
2995	// Return an error if no fix was discovered.
2996	if (RangeStatus != FRS_Success)
2997	return StmtError();
2998	}
2999
3000	assert(!BeginExpr.isInvalid() && !EndExpr.isInvalid() &&
3001	"invalid range expression in for loop");
3002
3003	// C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
3004	// C++1z removes this restriction.
3005	QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
3006	if (!Context.hasSameType(T1: BeginType, T2: EndType)) {
3007	Diag(RangeLoc, getLangOpts().CPlusPlus17
3008	? diag::warn_for_range_begin_end_types_differ
3009	: diag::ext_for_range_begin_end_types_differ)
3010	<< BeginType << EndType;
3011	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3012	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
3013	}
3014
3015	BeginDeclStmt =
3016	ActOnDeclStmt(dg: ConvertDeclToDeclGroup(BeginVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
3017	EndDeclStmt =
3018	ActOnDeclStmt(dg: ConvertDeclToDeclGroup(EndVar), StartLoc: ColonLoc, EndLoc: ColonLoc);
3019
3020	const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
3021	ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
3022	VK_LValue, ColonLoc);
3023	if (BeginRef.isInvalid())
3024	return StmtError();
3025
3026	ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(),
3027	VK_LValue, ColonLoc);
3028	if (EndRef.isInvalid())
3029	return StmtError();
3030
3031	// Build and check __begin != __end expression.
3032	NotEqExpr = ActOnBinOp(S, TokLoc: ColonLoc, Kind: tok::exclaimequal,
3033	LHSExpr: BeginRef.get(), RHSExpr: EndRef.get());
3034	if (!NotEqExpr.isInvalid())
3035	NotEqExpr = CheckBooleanCondition(Loc: ColonLoc, E: NotEqExpr.get());
3036	if (!NotEqExpr.isInvalid())
3037	NotEqExpr =
3038	ActOnFinishFullExpr(Expr: NotEqExpr.get(), /*DiscardedValue*/ false);
3039	if (NotEqExpr.isInvalid()) {
3040	Diag(RangeLoc, diag::note_for_range_invalid_iterator)
3041	<< RangeLoc << 0 << BeginRangeRef.get()->getType();
3042	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3043	if (!Context.hasSameType(T1: BeginType, T2: EndType))
3044	NoteForRangeBeginEndFunction(SemaRef&: *this, E: EndExpr.get(), BEF: BEF_end);
3045	return StmtError();
3046	}
3047
3048	// Build and check ++__begin expression.
3049	BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
3050	VK_LValue, ColonLoc);
3051	if (BeginRef.isInvalid())
3052	return StmtError();
3053
3054	IncrExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::plusplus, Input: BeginRef.get());
3055	if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
3056	// FIXME: getCurScope() should not be used during template instantiation.
3057	// We should pick up the set of unqualified lookup results for operator
3058	// co_await during the initial parse.
3059	IncrExpr = ActOnCoawaitExpr(S, KwLoc: CoawaitLoc, E: IncrExpr.get());
3060	if (!IncrExpr.isInvalid())
3061	IncrExpr = ActOnFinishFullExpr(Expr: IncrExpr.get(), /*DiscardedValue*/ false);
3062	if (IncrExpr.isInvalid()) {
3063	Diag(RangeLoc, diag::note_for_range_invalid_iterator)
3064	<< RangeLoc << 2 << BeginRangeRef.get()->getType() ;
3065	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3066	return StmtError();
3067	}
3068
3069	// Build and check *__begin expression.
3070	BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
3071	VK_LValue, ColonLoc);
3072	if (BeginRef.isInvalid())
3073	return StmtError();
3074
3075	ExprResult DerefExpr = ActOnUnaryOp(S, OpLoc: ColonLoc, Op: tok::star, Input: BeginRef.get());
3076	if (DerefExpr.isInvalid()) {
3077	Diag(RangeLoc, diag::note_for_range_invalid_iterator)
3078	<< RangeLoc << 1 << BeginRangeRef.get()->getType();
3079	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3080	return StmtError();
3081	}
3082
3083	// Attach *__begin as initializer for VD. Don't touch it if we're just
3084	// trying to determine whether this would be a valid range.
3085	if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
3086	AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false);
3087	if (LoopVar->isInvalidDecl() ||
3088	(LoopVar->getInit() && LoopVar->getInit()->containsErrors()))
3089	NoteForRangeBeginEndFunction(SemaRef&: *this, E: BeginExpr.get(), BEF: BEF_begin);
3090	}
3091	}
3092
3093	// Don't bother to actually allocate the result if we're just trying to
3094	// determine whether it would be valid.
3095	if (Kind == BFRK_Check)
3096	return StmtResult();
3097
3098	// In OpenMP loop region loop control variable must be private. Perform
3099	// analysis of first part (if any).
3100	if (getLangOpts().OpenMP >= 50 && BeginDeclStmt.isUsable())
3101	OpenMP().ActOnOpenMPLoopInitialization(ForLoc, Init: BeginDeclStmt.get());
3102
3103	return new (Context) CXXForRangeStmt(
3104	InitStmt, RangeDS, cast_or_null<DeclStmt>(Val: BeginDeclStmt.get()),
3105	cast_or_null<DeclStmt>(Val: EndDeclStmt.get()), NotEqExpr.get(),
3106	IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
3107	ColonLoc, RParenLoc);
3108	}
3109
3110	/// FinishObjCForCollectionStmt - Attach the body to a objective-C foreach
3111	/// statement.
3112	StmtResult Sema::FinishObjCForCollectionStmt(Stmt *S, Stmt *B) {
3113	if (!S || !B)
3114	return StmtError();
3115	ObjCForCollectionStmt * ForStmt = cast<ObjCForCollectionStmt>(Val: S);
3116
3117	ForStmt->setBody(B);
3118	return S;
3119	}
3120
3121	// Warn when the loop variable is a const reference that creates a copy.
3122	// Suggest using the non-reference type for copies. If a copy can be prevented
3123	// suggest the const reference type that would do so.
3124	// For instance, given "for (const &Foo : Range)", suggest
3125	// "for (const Foo : Range)" to denote a copy is made for the loop. If
3126	// possible, also suggest "for (const &Bar : Range)" if this type prevents
3127	// the copy altogether.
3128	static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
3129	const VarDecl *VD,
3130	QualType RangeInitType) {
3131	const Expr *InitExpr = VD->getInit();
3132	if (!InitExpr)
3133	return;
3134
3135	QualType VariableType = VD->getType();
3136
3137	if (auto Cleanups = dyn_cast<ExprWithCleanups>(Val: InitExpr))
3138	if (!Cleanups->cleanupsHaveSideEffects())
3139	InitExpr = Cleanups->getSubExpr();
3140
3141	const MaterializeTemporaryExpr *MTE =
3142	dyn_cast<MaterializeTemporaryExpr>(Val: InitExpr);
3143
3144	// No copy made.
3145	if (!MTE)
3146	return;
3147
3148	const Expr *E = MTE->getSubExpr()->IgnoreImpCasts();
3149
3150	// Searching for either UnaryOperator for dereference of a pointer or
3151	// CXXOperatorCallExpr for handling iterators.
3152	while (!isa<CXXOperatorCallExpr>(Val: E) && !isa<UnaryOperator>(Val: E)) {
3153	if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Val: E)) {
3154	E = CCE->getArg(Arg: 0);
3155	} else if (const CXXMemberCallExpr *Call = dyn_cast<CXXMemberCallExpr>(Val: E)) {
3156	const MemberExpr *ME = cast<MemberExpr>(Call->getCallee());
3157	E = ME->getBase();
3158	} else {
3159	const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(Val: E);
3160	E = MTE->getSubExpr();
3161	}
3162	E = E->IgnoreImpCasts();
3163	}
3164
3165	QualType ReferenceReturnType;
3166	if (isa<UnaryOperator>(Val: E)) {
3167	ReferenceReturnType = SemaRef.Context.getLValueReferenceType(T: E->getType());
3168	} else {
3169	const CXXOperatorCallExpr *Call = cast<CXXOperatorCallExpr>(Val: E);
3170	const FunctionDecl *FD = Call->getDirectCallee();
3171	QualType ReturnType = FD->getReturnType();
3172	if (ReturnType->isReferenceType())
3173	ReferenceReturnType = ReturnType;
3174	}
3175
3176	if (!ReferenceReturnType.isNull()) {
3177	// Loop variable creates a temporary. Suggest either to go with
3178	// non-reference loop variable to indicate a copy is made, or
3179	// the correct type to bind a const reference.
3180	SemaRef.Diag(VD->getLocation(),
3181	diag::warn_for_range_const_ref_binds_temp_built_from_ref)
3182	<< VD << VariableType << ReferenceReturnType;
3183	QualType NonReferenceType = VariableType.getNonReferenceType();
3184	NonReferenceType.removeLocalConst();
3185	QualType NewReferenceType =
3186	SemaRef.Context.getLValueReferenceType(T: E->getType().withConst());
3187	SemaRef.Diag(VD->getBeginLoc(), diag::note_use_type_or_non_reference)
3188	<< NonReferenceType << NewReferenceType << VD->getSourceRange()
3189	<< FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
3190	} else if (!VariableType->isRValueReferenceType()) {
3191	// The range always returns a copy, so a temporary is always created.
3192	// Suggest removing the reference from the loop variable.
3193	// If the type is a rvalue reference do not warn since that changes the
3194	// semantic of the code.
3195	SemaRef.Diag(VD->getLocation(), diag::warn_for_range_ref_binds_ret_temp)
3196	<< VD << RangeInitType;
3197	QualType NonReferenceType = VariableType.getNonReferenceType();
3198	NonReferenceType.removeLocalConst();
3199	SemaRef.Diag(VD->getBeginLoc(), diag::note_use_non_reference_type)
3200	<< NonReferenceType << VD->getSourceRange()
3201	<< FixItHint::CreateRemoval(VD->getTypeSpecEndLoc());
3202	}
3203	}
3204
3205	/// Determines whether the @p VariableType's declaration is a record with the
3206	/// clang::trivial_abi attribute.
3207	static bool hasTrivialABIAttr(QualType VariableType) {
3208	if (CXXRecordDecl *RD = VariableType->getAsCXXRecordDecl())
3209	return RD->hasAttr<TrivialABIAttr>();
3210
3211	return false;
3212	}
3213
3214	// Warns when the loop variable can be changed to a reference type to
3215	// prevent a copy. For instance, if given "for (const Foo x : Range)" suggest
3216	// "for (const Foo &x : Range)" if this form does not make a copy.
3217	static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef,
3218	const VarDecl *VD) {
3219	const Expr *InitExpr = VD->getInit();
3220	if (!InitExpr)
3221	return;
3222
3223	QualType VariableType = VD->getType();
3224
3225	if (const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(Val: InitExpr)) {
3226	if (!CE->getConstructor()->isCopyConstructor())
3227	return;
3228	} else if (const CastExpr *CE = dyn_cast<CastExpr>(Val: InitExpr)) {
3229	if (CE->getCastKind() != CK_LValueToRValue)
3230	return;
3231	} else {
3232	return;
3233	}
3234
3235	// Small trivially copyable types are cheap to copy. Do not emit the
3236	// diagnostic for these instances. 64 bytes is a common size of a cache line.
3237	// (The function `getTypeSize` returns the size in bits.)
3238	ASTContext &Ctx = SemaRef.Context;
3239	if (Ctx.getTypeSize(T: VariableType) <= 64 * 8 &&
3240	(VariableType.isTriviallyCopyConstructibleType(Context: Ctx) ||
3241	hasTrivialABIAttr(VariableType)))
3242	return;
3243
3244	// Suggest changing from a const variable to a const reference variable
3245	// if doing so will prevent a copy.
3246	SemaRef.Diag(VD->getLocation(), diag::warn_for_range_copy)
3247	<< VD << VariableType;
3248	SemaRef.Diag(VD->getBeginLoc(), diag::note_use_reference_type)
3249	<< SemaRef.Context.getLValueReferenceType(VariableType)
3250	<< VD->getSourceRange()
3251	<< FixItHint::CreateInsertion(VD->getLocation(), "&");
3252	}
3253
3254	/// DiagnoseForRangeVariableCopies - Diagnose three cases and fixes for them.
3255	/// 1) for (const foo &x : foos) where foos only returns a copy. Suggest
3256	/// using "const foo x" to show that a copy is made
3257	/// 2) for (const bar &x : foos) where bar is a temporary initialized by bar.
3258	/// Suggest either "const bar x" to keep the copying or "const foo& x" to
3259	/// prevent the copy.
3260	/// 3) for (const foo x : foos) where x is constructed from a reference foo.
3261	/// Suggest "const foo &x" to prevent the copy.
3262	static void DiagnoseForRangeVariableCopies(Sema &SemaRef,
3263	const CXXForRangeStmt *ForStmt) {
3264	if (SemaRef.inTemplateInstantiation())
3265	return;
3266
3267	if (SemaRef.Diags.isIgnored(
3268	diag::warn_for_range_const_ref_binds_temp_built_from_ref,
3269	ForStmt->getBeginLoc()) &&
3270	SemaRef.Diags.isIgnored(diag::warn_for_range_ref_binds_ret_temp,
3271	ForStmt->getBeginLoc()) &&
3272	SemaRef.Diags.isIgnored(diag::warn_for_range_copy,
3273	ForStmt->getBeginLoc())) {
3274	return;
3275	}
3276
3277	const VarDecl *VD = ForStmt->getLoopVariable();
3278	if (!VD)
3279	return;
3280
3281	QualType VariableType = VD->getType();
3282
3283	if (VariableType->isIncompleteType())
3284	return;
3285
3286	const Expr *InitExpr = VD->getInit();
3287	if (!InitExpr)
3288	return;
3289
3290	if (InitExpr->getExprLoc().isMacroID())
3291	return;
3292
3293	if (VariableType->isReferenceType()) {
3294	DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,
3295	RangeInitType: ForStmt->getRangeInit()->getType());
3296	} else if (VariableType.isConstQualified()) {
3297	DiagnoseForRangeConstVariableCopies(SemaRef, VD);
3298	}
3299	}
3300
3301	/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement.
3302	/// This is a separate step from ActOnCXXForRangeStmt because analysis of the
3303	/// body cannot be performed until after the type of the range variable is
3304	/// determined.
3305	StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) {
3306	if (!S || !B)
3307	return StmtError();
3308
3309	if (isa<ObjCForCollectionStmt>(Val: S))
3310	return FinishObjCForCollectionStmt(S, B);
3311
3312	CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(Val: S);
3313	ForStmt->setBody(B);
3314
3315	DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B,
3316	diag::warn_empty_range_based_for_body);
3317
3318	DiagnoseForRangeVariableCopies(SemaRef&: *this, ForStmt);
3319
3320	return S;
3321	}
3322
3323	StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc,
3324	SourceLocation LabelLoc,
3325	LabelDecl *TheDecl) {
3326	setFunctionHasBranchIntoScope();
3327
3328	// If this goto is in a compute construct scope, we need to make sure we check
3329	// gotos in/out.
3330	if (getCurScope()->isInOpenACCComputeConstructScope())
3331	setFunctionHasBranchProtectedScope();
3332
3333	TheDecl->markUsed(Context);
3334	return new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc);
3335	}
3336
3337	StmtResult
3338	Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
3339	Expr *E) {
3340	// Convert operand to void*
3341	if (!E->isTypeDependent()) {
3342	QualType ETy = E->getType();
3343	QualType DestTy = Context.getPointerType(Context.VoidTy.withConst());
3344	ExprResult ExprRes = E;
3345	AssignConvertType ConvTy =
3346	CheckSingleAssignmentConstraints(LHSType: DestTy, RHS&: ExprRes);
3347	if (ExprRes.isInvalid())
3348	return StmtError();
3349	E = ExprRes.get();
3350	if (DiagnoseAssignmentResult(ConvTy, Loc: StarLoc, DstType: DestTy, SrcType: ETy, SrcExpr: E, Action: AA_Passing))
3351	return StmtError();
3352	}
3353
3354	ExprResult ExprRes = ActOnFinishFullExpr(Expr: E, /*DiscardedValue*/ false);
3355	if (ExprRes.isInvalid())
3356	return StmtError();
3357	E = ExprRes.get();
3358
3359	setFunctionHasIndirectGoto();
3360
3361	// If this goto is in a compute construct scope, we need to make sure we
3362	// check gotos in/out.
3363	if (getCurScope()->isInOpenACCComputeConstructScope())
3364	setFunctionHasBranchProtectedScope();
3365
3366	return new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E);
3367	}
3368
3369	static void CheckJumpOutOfSEHFinally(Sema &S, SourceLocation Loc,
3370	const Scope &DestScope) {
3371	if (!S.CurrentSEHFinally.empty() &&
3372	DestScope.Contains(rhs: *S.CurrentSEHFinally.back())) {
3373	S.Diag(Loc, diag::warn_jump_out_of_seh_finally);
3374	}
3375	}
3376
3377	StmtResult
3378	Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) {
3379	Scope *S = CurScope->getContinueParent();
3380	if (!S) {
3381	// C99 6.8.6.2p1: A break shall appear only in or as a loop body.
3382	return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop));
3383	}
3384	if (S->isConditionVarScope()) {
3385	// We cannot 'continue;' from within a statement expression in the
3386	// initializer of a condition variable because we would jump past the
3387	// initialization of that variable.
3388	return StmtError(Diag(ContinueLoc, diag::err_continue_from_cond_var_init));
3389	}
3390
3391	// A 'continue' that would normally have execution continue on a block outside
3392	// of a compute construct counts as 'branching out of' the compute construct,
3393	// so diagnose here.
3394	if (S->isOpenACCComputeConstructScope())
3395	return StmtError(
3396	Diag(ContinueLoc, diag::err_acc_branch_in_out_compute_construct)
3397	<< /*branch*/ 0 << /*out of */ 0);
3398
3399	CheckJumpOutOfSEHFinally(S&: *this, Loc: ContinueLoc, DestScope: *S);
3400
3401	return new (Context) ContinueStmt(ContinueLoc);
3402	}
3403
3404	StmtResult
3405	Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
3406	Scope *S = CurScope->getBreakParent();
3407	if (!S) {
3408	// C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body.
3409	return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch));
3410	}
3411	if (S->isOpenMPLoopScope())
3412	return StmtError(Diag(BreakLoc, diag::err_omp_loop_cannot_use_stmt)
3413	<< "break");
3414
3415	// OpenACC doesn't allow 'break'ing from a compute construct, so diagnose if
3416	// we are trying to do so. This can come in 2 flavors: 1-the break'able thing
3417	// (besides the compute construct) 'contains' the compute construct, at which
3418	// point the 'break' scope will be the compute construct. Else it could be a
3419	// loop of some sort that has a direct parent of the compute construct.
3420	// However, a 'break' in a 'switch' marked as a compute construct doesn't
3421	// count as 'branch out of' the compute construct.
3422	if (S->isOpenACCComputeConstructScope() ||
3423	(S->isLoopScope() && S->getParent() &&
3424	S->getParent()->isOpenACCComputeConstructScope()))
3425	return StmtError(
3426	Diag(BreakLoc, diag::err_acc_branch_in_out_compute_construct)
3427	<< /*branch*/ 0 << /*out of */ 0);
3428
3429	CheckJumpOutOfSEHFinally(S&: *this, Loc: BreakLoc, DestScope: *S);
3430
3431	return new (Context) BreakStmt(BreakLoc);
3432	}
3433
3434	/// Determine whether the given expression might be move-eligible or
3435	/// copy-elidable in either a (co_)return statement or throw expression,
3436	/// without considering function return type, if applicable.
3437	///
3438	/// \param E The expression being returned from the function or block,
3439	/// being thrown, or being co_returned from a coroutine. This expression
3440	/// might be modified by the implementation.
3441	///
3442	/// \param Mode Overrides detection of current language mode
3443	/// and uses the rules for C++23.
3444	///
3445	/// \returns An aggregate which contains the Candidate and isMoveEligible
3446	/// and isCopyElidable methods. If Candidate is non-null, it means
3447	/// isMoveEligible() would be true under the most permissive language standard.
3448	Sema::NamedReturnInfo Sema::getNamedReturnInfo(Expr *&E,
3449	SimplerImplicitMoveMode Mode) {
3450	if (!E)
3451	return NamedReturnInfo();
3452	// - in a return statement in a function [where] ...
3453	// ... the expression is the name of a non-volatile automatic object ...
3454	const auto *DR = dyn_cast<DeclRefExpr>(Val: E->IgnoreParens());
3455	if (!DR || DR->refersToEnclosingVariableOrCapture())
3456	return NamedReturnInfo();
3457	const auto *VD = dyn_cast<VarDecl>(Val: DR->getDecl());
3458	if (!VD)
3459	return NamedReturnInfo();
3460	if (VD->getInit() && VD->getInit()->containsErrors())
3461	return NamedReturnInfo();
3462	NamedReturnInfo Res = getNamedReturnInfo(VD);
3463	if (Res.Candidate && !E->isXValue() &&
3464	(Mode == SimplerImplicitMoveMode::ForceOn ||
3465	(Mode != SimplerImplicitMoveMode::ForceOff &&
3466	getLangOpts().CPlusPlus23))) {
3467	E = ImplicitCastExpr::Create(Context, T: VD->getType().getNonReferenceType(),
3468	Kind: CK_NoOp, Operand: E, BasePath: nullptr, Cat: VK_XValue,
3469	FPO: FPOptionsOverride());
3470	}
3471	return Res;
3472	}
3473
3474	/// Determine whether the given NRVO candidate variable is move-eligible or
3475	/// copy-elidable, without considering function return type.
3476	///
3477	/// \param VD The NRVO candidate variable.
3478	///
3479	/// \returns An aggregate which contains the Candidate and isMoveEligible
3480	/// and isCopyElidable methods. If Candidate is non-null, it means
3481	/// isMoveEligible() would be true under the most permissive language standard.
3482	Sema::NamedReturnInfo Sema::getNamedReturnInfo(const VarDecl *VD) {
3483	NamedReturnInfo Info{.Candidate: VD, .S: NamedReturnInfo::MoveEligibleAndCopyElidable};
3484
3485	// C++20 [class.copy.elision]p3:
3486	// - in a return statement in a function with ...
3487	// (other than a function ... parameter)
3488	if (VD->getKind() == Decl::ParmVar)
3489	Info.S = NamedReturnInfo::MoveEligible;
3490	else if (VD->getKind() != Decl::Var)
3491	return NamedReturnInfo();
3492
3493	// (other than ... a catch-clause parameter)
3494	if (VD->isExceptionVariable())
3495	Info.S = NamedReturnInfo::MoveEligible;
3496
3497	// ...automatic...
3498	if (!VD->hasLocalStorage())
3499	return NamedReturnInfo();
3500
3501	// We don't want to implicitly move out of a __block variable during a return
3502	// because we cannot assume the variable will no longer be used.
3503	if (VD->hasAttr<BlocksAttr>())
3504	return NamedReturnInfo();
3505
3506	QualType VDType = VD->getType();
3507	if (VDType->isObjectType()) {
3508	// C++17 [class.copy.elision]p3:
3509	// ...non-volatile automatic object...
3510	if (VDType.isVolatileQualified())
3511	return NamedReturnInfo();
3512	} else if (VDType->isRValueReferenceType()) {
3513	// C++20 [class.copy.elision]p3:
3514	// ...either a non-volatile object or an rvalue reference to a non-volatile
3515	// object type...
3516	QualType VDReferencedType = VDType.getNonReferenceType();
3517	if (VDReferencedType.isVolatileQualified() ||
3518	!VDReferencedType->isObjectType())
3519	return NamedReturnInfo();
3520	Info.S = NamedReturnInfo::MoveEligible;
3521	} else {
3522	return NamedReturnInfo();
3523	}
3524
3525	// Variables with higher required alignment than their type's ABI
3526	// alignment cannot use NRVO.
3527	if (!VD->hasDependentAlignment() &&
3528	Context.getDeclAlign(VD) > Context.getTypeAlignInChars(T: VDType))
3529	Info.S = NamedReturnInfo::MoveEligible;
3530
3531	return Info;
3532	}
3533
3534	/// Updates given NamedReturnInfo's move-eligible and
3535	/// copy-elidable statuses, considering the function
3536	/// return type criteria as applicable to return statements.
3537	///
3538	/// \param Info The NamedReturnInfo object to update.
3539	///
3540	/// \param ReturnType This is the return type of the function.
3541	/// \returns The copy elision candidate, in case the initial return expression
3542	/// was copy elidable, or nullptr otherwise.
3543	const VarDecl *Sema::getCopyElisionCandidate(NamedReturnInfo &Info,
3544	QualType ReturnType) {
3545	if (!Info.Candidate)
3546	return nullptr;
3547
3548	auto invalidNRVO = [&] {
3549	Info = NamedReturnInfo();
3550	return nullptr;
3551	};
3552
3553	// If we got a non-deduced auto ReturnType, we are in a dependent context and
3554	// there is no point in allowing copy elision since we won't have it deduced
3555	// by the point the VardDecl is instantiated, which is the last chance we have
3556	// of deciding if the candidate is really copy elidable.
3557	if ((ReturnType->getTypeClass() == Type::TypeClass::Auto &&
3558	ReturnType->isCanonicalUnqualified()) ||
3559	ReturnType->isSpecificBuiltinType(BuiltinType::Dependent))
3560	return invalidNRVO();
3561
3562	if (!ReturnType->isDependentType()) {
3563	// - in a return statement in a function with ...
3564	// ... a class return type ...
3565	if (!ReturnType->isRecordType())
3566	return invalidNRVO();
3567
3568	QualType VDType = Info.Candidate->getType();
3569	// ... the same cv-unqualified type as the function return type ...
3570	// When considering moving this expression out, allow dissimilar types.
3571	if (!VDType->isDependentType() &&
3572	!Context.hasSameUnqualifiedType(T1: ReturnType, T2: VDType))
3573	Info.S = NamedReturnInfo::MoveEligible;
3574	}
3575	return Info.isCopyElidable() ? Info.Candidate : nullptr;
3576	}
3577
3578	/// Verify that the initialization sequence that was picked for the
3579	/// first overload resolution is permissible under C++98.
3580	///
3581	/// Reject (possibly converting) constructors not taking an rvalue reference,
3582	/// or user conversion operators which are not ref-qualified.
3583	static bool
3584	VerifyInitializationSequenceCXX98(const Sema &S,
3585	const InitializationSequence &Seq) {
3586	const auto *Step = llvm::find_if(Range: Seq.steps(), P: [](const auto &Step) {
3587	return Step.Kind == InitializationSequence::SK_ConstructorInitialization ||
3588	Step.Kind == InitializationSequence::SK_UserConversion;
3589	});
3590	if (Step != Seq.step_end()) {
3591	const auto *FD = Step->Function.Function;
3592	if (isa<CXXConstructorDecl>(Val: FD)
3593	? !FD->getParamDecl(i: 0)->getType()->isRValueReferenceType()
3594	: cast<CXXMethodDecl>(Val: FD)->getRefQualifier() == RQ_None)
3595	return false;
3596	}
3597	return true;
3598	}
3599
3600	/// Perform the initialization of a potentially-movable value, which
3601	/// is the result of return value.
3602	///
3603	/// This routine implements C++20 [class.copy.elision]p3, which attempts to
3604	/// treat returned lvalues as rvalues in certain cases (to prefer move
3605	/// construction), then falls back to treating them as lvalues if that failed.
3606	ExprResult Sema::PerformMoveOrCopyInitialization(
3607	const InitializedEntity &Entity, const NamedReturnInfo &NRInfo, Expr *Value,
3608	bool SupressSimplerImplicitMoves) {
3609	if (getLangOpts().CPlusPlus &&
3610	(!getLangOpts().CPlusPlus23 || SupressSimplerImplicitMoves) &&
3611	NRInfo.isMoveEligible()) {
3612	ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
3613	CK_NoOp, Value, VK_XValue, FPOptionsOverride());
3614	Expr *InitExpr = &AsRvalue;
3615	auto Kind = InitializationKind::CreateCopy(InitLoc: Value->getBeginLoc(),
3616	EqualLoc: Value->getBeginLoc());
3617	InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3618	auto Res = Seq.getFailedOverloadResult();
3619	if ((Res == OR_Success || Res == OR_Deleted) &&
3620	(getLangOpts().CPlusPlus11 ||
3621	VerifyInitializationSequenceCXX98(S: *this, Seq))) {
3622	// Promote "AsRvalue" to the heap, since we now need this
3623	// expression node to persist.
3624	Value =
3625	ImplicitCastExpr::Create(Context, T: Value->getType(), Kind: CK_NoOp, Operand: Value,
3626	BasePath: nullptr, Cat: VK_XValue, FPO: FPOptionsOverride());
3627	// Complete type-checking the initialization of the return type
3628	// using the constructor we found.
3629	return Seq.Perform(S&: *this, Entity, Kind: Kind, Args: Value);
3630	}
3631	}
3632	// Either we didn't meet the criteria for treating an lvalue as an rvalue,
3633	// above, or overload resolution failed. Either way, we need to try
3634	// (again) now with the return value expression as written.
3635	return PerformCopyInitialization(Entity, EqualLoc: SourceLocation(), Init: Value);
3636	}
3637
3638	/// Determine whether the declared return type of the specified function
3639	/// contains 'auto'.
3640	static bool hasDeducedReturnType(FunctionDecl *FD) {
3641	const FunctionProtoType *FPT =
3642	FD->getTypeSourceInfo()->getType()->castAs<FunctionProtoType>();
3643	return FPT->getReturnType()->isUndeducedType();
3644	}
3645
3646	/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements
3647	/// for capturing scopes.
3648	///
3649	StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
3650	Expr *RetValExp,
3651	NamedReturnInfo &NRInfo,
3652	bool SupressSimplerImplicitMoves) {
3653	// If this is the first return we've seen, infer the return type.
3654	// [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
3655	CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(Val: getCurFunction());
3656	QualType FnRetType = CurCap->ReturnType;
3657	LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(Val: CurCap);
3658	if (CurLambda && CurLambda->CallOperator->getType().isNull())
3659	return StmtError();
3660	bool HasDeducedReturnType =
3661	CurLambda && hasDeducedReturnType(CurLambda->CallOperator);
3662
3663	if (ExprEvalContexts.back().isDiscardedStatementContext() &&
3664	(HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
3665	if (RetValExp) {
3666	ExprResult ER =
3667	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3668	if (ER.isInvalid())
3669	return StmtError();
3670	RetValExp = ER.get();
3671	}
3672	return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
3673	/* NRVOCandidate=*/nullptr);
3674	}
3675
3676	if (HasDeducedReturnType) {
3677	FunctionDecl *FD = CurLambda->CallOperator;
3678	// If we've already decided this lambda is invalid, e.g. because
3679	// we saw a `return` whose expression had an error, don't keep
3680	// trying to deduce its return type.
3681	if (FD->isInvalidDecl())
3682	return StmtError();
3683	// In C++1y, the return type may involve 'auto'.
3684	// FIXME: Blocks might have a return type of 'auto' explicitly specified.
3685	if (CurCap->ReturnType.isNull())
3686	CurCap->ReturnType = FD->getReturnType();
3687
3688	AutoType *AT = CurCap->ReturnType->getContainedAutoType();
3689	assert(AT && "lost auto type from lambda return type");
3690	if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
3691	FD->setInvalidDecl();
3692	// FIXME: preserve the ill-formed return expression.
3693	return StmtError();
3694	}
3695	CurCap->ReturnType = FnRetType = FD->getReturnType();
3696	} else if (CurCap->HasImplicitReturnType) {
3697	// For blocks/lambdas with implicit return types, we check each return
3698	// statement individually, and deduce the common return type when the block
3699	// or lambda is completed.
3700	// FIXME: Fold this into the 'auto' codepath above.
3701	if (RetValExp && !isa<InitListExpr>(Val: RetValExp)) {
3702	ExprResult Result = DefaultFunctionArrayLvalueConversion(E: RetValExp);
3703	if (Result.isInvalid())
3704	return StmtError();
3705	RetValExp = Result.get();
3706
3707	// DR1048: even prior to C++14, we should use the 'auto' deduction rules
3708	// when deducing a return type for a lambda-expression (or by extension
3709	// for a block). These rules differ from the stated C++11 rules only in
3710	// that they remove top-level cv-qualifiers.
3711	if (!CurContext->isDependentContext())
3712	FnRetType = RetValExp->getType().getUnqualifiedType();
3713	else
3714	FnRetType = CurCap->ReturnType = Context.DependentTy;
3715	} else {
3716	if (RetValExp) {
3717	// C++11 [expr.lambda.prim]p4 bans inferring the result from an
3718	// initializer list, because it is not an expression (even
3719	// though we represent it as one). We still deduce 'void'.
3720	Diag(ReturnLoc, diag::err_lambda_return_init_list)
3721	<< RetValExp->getSourceRange();
3722	}
3723
3724	FnRetType = Context.VoidTy;
3725	}
3726
3727	// Although we'll properly infer the type of the block once it's completed,
3728	// make sure we provide a return type now for better error recovery.
3729	if (CurCap->ReturnType.isNull())
3730	CurCap->ReturnType = FnRetType;
3731	}
3732	const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
3733
3734	if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap)) {
3735	if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
3736	Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr);
3737	return StmtError();
3738	}
3739	} else if (auto *CurRegion = dyn_cast<CapturedRegionScopeInfo>(Val: CurCap)) {
3740	Diag(ReturnLoc, diag::err_return_in_captured_stmt) << CurRegion->getRegionName();
3741	return StmtError();
3742	} else {
3743	assert(CurLambda && "unknown kind of captured scope");
3744	if (CurLambda->CallOperator->getType()
3745	->castAs<FunctionType>()
3746	->getNoReturnAttr()) {
3747	Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr);
3748	return StmtError();
3749	}
3750	}
3751
3752	// Otherwise, verify that this result type matches the previous one. We are
3753	// pickier with blocks than for normal functions because we don't have GCC
3754	// compatibility to worry about here.
3755	if (FnRetType->isDependentType()) {
3756	// Delay processing for now. TODO: there are lots of dependent
3757	// types we can conclusively prove aren't void.
3758	} else if (FnRetType->isVoidType()) {
3759	if (RetValExp && !isa<InitListExpr>(Val: RetValExp) &&
3760	!(getLangOpts().CPlusPlus &&
3761	(RetValExp->isTypeDependent() ||
3762	RetValExp->getType()->isVoidType()))) {
3763	if (!getLangOpts().CPlusPlus &&
3764	RetValExp->getType()->isVoidType())
3765	Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2;
3766	else {
3767	Diag(ReturnLoc, diag::err_return_block_has_expr);
3768	RetValExp = nullptr;
3769	}
3770	}
3771	} else if (!RetValExp) {
3772	return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr));
3773	} else if (!RetValExp->isTypeDependent()) {
3774	// we have a non-void block with an expression, continue checking
3775
3776	// C99 6.8.6.4p3(136): The return statement is not an assignment. The
3777	// overlap restriction of subclause 6.5.16.1 does not apply to the case of
3778	// function return.
3779
3780	// In C++ the return statement is handled via a copy initialization.
3781	// the C version of which boils down to CheckSingleAssignmentConstraints.
3782	InitializedEntity Entity =
3783	InitializedEntity::InitializeResult(ReturnLoc, Type: FnRetType);
3784	ExprResult Res = PerformMoveOrCopyInitialization(
3785	Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
3786	if (Res.isInvalid()) {
3787	// FIXME: Cleanup temporaries here, anyway?
3788	return StmtError();
3789	}
3790	RetValExp = Res.get();
3791	CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc);
3792	}
3793
3794	if (RetValExp) {
3795	ExprResult ER =
3796	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
3797	if (ER.isInvalid())
3798	return StmtError();
3799	RetValExp = ER.get();
3800	}
3801	auto *Result =
3802	ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
3803
3804	// If we need to check for the named return value optimization,
3805	// or if we need to infer the return type,
3806	// save the return statement in our scope for later processing.
3807	if (CurCap->HasImplicitReturnType || NRVOCandidate)
3808	FunctionScopes.back()->Returns.push_back(Elt: Result);
3809
3810	if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
3811	FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
3812
3813	if (auto *CurBlock = dyn_cast<BlockScopeInfo>(Val: CurCap);
3814	CurBlock && CurCap->HasImplicitReturnType && RetValExp &&
3815	RetValExp->containsErrors())
3816	CurBlock->TheDecl->setInvalidDecl();
3817
3818	return Result;
3819	}
3820
3821	namespace {
3822	/// Marks all typedefs in all local classes in a type referenced.
3823	///
3824	/// In a function like
3825	/// auto f() {
3826	/// struct S { typedef int a; };
3827	/// return S();
3828	/// }
3829	///
3830	/// the local type escapes and could be referenced in some TUs but not in
3831	/// others. Pretend that all local typedefs are always referenced, to not warn
3832	/// on this. This isn't necessary if f has internal linkage, or the typedef
3833	/// is private.
3834	class LocalTypedefNameReferencer
3835	: public RecursiveASTVisitor<LocalTypedefNameReferencer> {
3836	public:
3837	LocalTypedefNameReferencer(Sema &S) : S(S) {}
3838	bool VisitRecordType(const RecordType *RT);
3839	private:
3840	Sema &S;
3841	};
3842	bool LocalTypedefNameReferencer::VisitRecordType(const RecordType *RT) {
3843	auto *R = dyn_cast<CXXRecordDecl>(Val: RT->getDecl());
3844	if (!R || !R->isLocalClass() || !R->isLocalClass()->isExternallyVisible() ||
3845	R->isDependentType())
3846	return true;
3847	for (auto *TmpD : R->decls())
3848	if (auto *T = dyn_cast<TypedefNameDecl>(TmpD))
3849	if (T->getAccess() != AS_private || R->hasFriends())
3850	S.MarkAnyDeclReferenced(T->getLocation(), T, /*OdrUse=*/false);
3851	return true;
3852	}
3853	}
3854
3855	TypeLoc Sema::getReturnTypeLoc(FunctionDecl *FD) const {
3856	return FD->getTypeSourceInfo()
3857	->getTypeLoc()
3858	.getAsAdjusted<FunctionProtoTypeLoc>()
3859	.getReturnLoc();
3860	}
3861
3862	/// Deduce the return type for a function from a returned expression, per
3863	/// C++1y [dcl.spec.auto]p6.
3864	bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
3865	SourceLocation ReturnLoc,
3866	Expr *RetExpr, const AutoType *AT) {
3867	// If this is the conversion function for a lambda, we choose to deduce its
3868	// type from the corresponding call operator, not from the synthesized return
3869	// statement within it. See Sema::DeduceReturnType.
3870	if (isLambdaConversionOperator(FD))
3871	return false;
3872
3873	if (RetExpr && isa<InitListExpr>(Val: RetExpr)) {
3874	// If the deduction is for a return statement and the initializer is
3875	// a braced-init-list, the program is ill-formed.
3876	Diag(RetExpr->getExprLoc(),
3877	getCurLambda() ? diag::err_lambda_return_init_list
3878	: diag::err_auto_fn_return_init_list)
3879	<< RetExpr->getSourceRange();
3880	return true;
3881	}
3882
3883	if (FD->isDependentContext()) {
3884	// C++1y [dcl.spec.auto]p12:
3885	// Return type deduction [...] occurs when the definition is
3886	// instantiated even if the function body contains a return
3887	// statement with a non-type-dependent operand.
3888	assert(AT->isDeduced() && "should have deduced to dependent type");
3889	return false;
3890	}
3891
3892	TypeLoc OrigResultType = getReturnTypeLoc(FD);
3893	// In the case of a return with no operand, the initializer is considered
3894	// to be void().
3895	CXXScalarValueInitExpr VoidVal(Context.VoidTy, nullptr, SourceLocation());
3896	if (!RetExpr) {
3897	// For a function with a deduced result type to return with omitted
3898	// expression, the result type as written must be 'auto' or
3899	// 'decltype(auto)', possibly cv-qualified or constrained, but not
3900	// ref-qualified.
3901	if (!OrigResultType.getType()->getAs<AutoType>()) {
3902	Diag(ReturnLoc, diag::err_auto_fn_return_void_but_not_auto)
3903	<< OrigResultType.getType();
3904	return true;
3905	}
3906	RetExpr = &VoidVal;
3907	}
3908
3909	QualType Deduced = AT->getDeducedType();
3910	{
3911	// Otherwise, [...] deduce a value for U using the rules of template
3912	// argument deduction.
3913	auto RetExprLoc = RetExpr->getExprLoc();
3914	TemplateDeductionInfo Info(RetExprLoc);
3915	SourceLocation TemplateSpecLoc;
3916	if (RetExpr->getType() == Context.OverloadTy) {
3917	auto FindResult = OverloadExpr::find(E: RetExpr);
3918	if (FindResult.Expression)
3919	TemplateSpecLoc = FindResult.Expression->getNameLoc();
3920	}
3921	TemplateSpecCandidateSet FailedTSC(TemplateSpecLoc);
3922	TemplateDeductionResult Res = DeduceAutoType(
3923	AutoTypeLoc: OrigResultType, Initializer: RetExpr, Result&: Deduced, Info, /*DependentDeduction=*/false,
3924	/*IgnoreConstraints=*/false, FailedTSC: &FailedTSC);
3925	if (Res != TemplateDeductionResult::Success && FD->isInvalidDecl())
3926	return true;
3927	switch (Res) {
3928	case TemplateDeductionResult::Success:
3929	break;
3930	case TemplateDeductionResult::AlreadyDiagnosed:
3931	return true;
3932	case TemplateDeductionResult::Inconsistent: {
3933	// If a function with a declared return type that contains a placeholder
3934	// type has multiple return statements, the return type is deduced for
3935	// each return statement. [...] if the type deduced is not the same in
3936	// each deduction, the program is ill-formed.
3937	const LambdaScopeInfo *LambdaSI = getCurLambda();
3938	if (LambdaSI && LambdaSI->HasImplicitReturnType)
3939	Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
3940	<< Info.SecondArg << Info.FirstArg << true /*IsLambda*/;
3941	else
3942	Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
3943	<< (AT->isDecltypeAuto() ? 1 : 0) << Info.SecondArg
3944	<< Info.FirstArg;
3945	return true;
3946	}
3947	default:
3948	Diag(RetExpr->getExprLoc(), diag::err_auto_fn_deduction_failure)
3949	<< OrigResultType.getType() << RetExpr->getType();
3950	FailedTSC.NoteCandidates(S&: *this, Loc: RetExprLoc);
3951	return true;
3952	}
3953	}
3954
3955	// If a local type is part of the returned type, mark its fields as
3956	// referenced.
3957	LocalTypedefNameReferencer(*this).TraverseType(T: RetExpr->getType());
3958
3959	// CUDA: Kernel function must have 'void' return type.
3960	if (getLangOpts().CUDA && FD->hasAttr<CUDAGlobalAttr>() &&
3961	!Deduced->isVoidType()) {
3962	Diag(FD->getLocation(), diag::err_kern_type_not_void_return)
3963	<< FD->getType() << FD->getSourceRange();
3964	return true;
3965	}
3966
3967	if (!FD->isInvalidDecl() && AT->getDeducedType() != Deduced)
3968	// Update all declarations of the function to have the deduced return type.
3969	Context.adjustDeducedFunctionResultType(FD, ResultType: Deduced);
3970
3971	return false;
3972	}
3973
3974	StmtResult
3975	Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
3976	Scope *CurScope) {
3977	// Correct typos, in case the containing function returns 'auto' and
3978	// RetValExp should determine the deduced type.
3979	ExprResult RetVal = CorrectDelayedTyposInExpr(
3980	E: RetValExp, InitDecl: nullptr, /*RecoverUncorrectedTypos=*/true);
3981	if (RetVal.isInvalid())
3982	return StmtError();
3983
3984	if (getCurScope()->isInOpenACCComputeConstructScope())
3985	return StmtError(
3986	Diag(ReturnLoc, diag::err_acc_branch_in_out_compute_construct)
3987	<< /*return*/ 1 << /*out of */ 0);
3988
3989	StmtResult R =
3990	BuildReturnStmt(ReturnLoc, RetValExp: RetVal.get(), /*AllowRecovery=*/true);
3991	if (R.isInvalid() || ExprEvalContexts.back().isDiscardedStatementContext())
3992	return R;
3993
3994	VarDecl *VD =
3995	const_cast<VarDecl *>(cast<ReturnStmt>(Val: R.get())->getNRVOCandidate());
3996
3997	CurScope->updateNRVOCandidate(VD);
3998
3999	CheckJumpOutOfSEHFinally(S&: *this, Loc: ReturnLoc, DestScope: *CurScope->getFnParent());
4000
4001	return R;
4002	}
4003
4004	static bool CheckSimplerImplicitMovesMSVCWorkaround(const Sema &S,
4005	const Expr *E) {
4006	if (!E || !S.getLangOpts().CPlusPlus23 || !S.getLangOpts().MSVCCompat)
4007	return false;
4008	const Decl *D = E->getReferencedDeclOfCallee();
4009	if (!D || !S.SourceMgr.isInSystemHeader(Loc: D->getLocation()))
4010	return false;
4011	for (const DeclContext *DC = D->getDeclContext(); DC; DC = DC->getParent()) {
4012	if (DC->isStdNamespace())
4013	return true;
4014	}
4015	return false;
4016	}
4017
4018	StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
4019	bool AllowRecovery) {
4020	// Check for unexpanded parameter packs.
4021	if (RetValExp && DiagnoseUnexpandedParameterPack(E: RetValExp))
4022	return StmtError();
4023
4024	// HACK: We suppress simpler implicit move here in msvc compatibility mode
4025	// just as a temporary work around, as the MSVC STL has issues with
4026	// this change.
4027	bool SupressSimplerImplicitMoves =
4028	CheckSimplerImplicitMovesMSVCWorkaround(S: *this, E: RetValExp);
4029	NamedReturnInfo NRInfo = getNamedReturnInfo(
4030	E&: RetValExp, Mode: SupressSimplerImplicitMoves ? SimplerImplicitMoveMode::ForceOff
4031	: SimplerImplicitMoveMode::Normal);
4032
4033	if (isa<CapturingScopeInfo>(Val: getCurFunction()))
4034	return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp, NRInfo,
4035	SupressSimplerImplicitMoves);
4036
4037	QualType FnRetType;
4038	QualType RelatedRetType;
4039	const AttrVec *Attrs = nullptr;
4040	bool isObjCMethod = false;
4041
4042	if (const FunctionDecl *FD = getCurFunctionDecl()) {
4043	FnRetType = FD->getReturnType();
4044	if (FD->hasAttrs())
4045	Attrs = &FD->getAttrs();
4046	if (FD->isNoReturn())
4047	Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) << FD;
4048	if (FD->isMain() && RetValExp)
4049	if (isa<CXXBoolLiteralExpr>(RetValExp))
4050	Diag(ReturnLoc, diag::warn_main_returns_bool_literal)
4051	<< RetValExp->getSourceRange();
4052	if (FD->hasAttr<CmseNSEntryAttr>() && RetValExp) {
4053	if (const auto *RT = dyn_cast<RecordType>(Val: FnRetType.getCanonicalType())) {
4054	if (RT->getDecl()->isOrContainsUnion())
4055	Diag(RetValExp->getBeginLoc(), diag::warn_cmse_nonsecure_union) << 1;
4056	}
4057	}
4058	} else if (ObjCMethodDecl *MD = getCurMethodDecl()) {
4059	FnRetType = MD->getReturnType();
4060	isObjCMethod = true;
4061	if (MD->hasAttrs())
4062	Attrs = &MD->getAttrs();
4063	if (MD->hasRelatedResultType() && MD->getClassInterface()) {
4064	// In the implementation of a method with a related return type, the
4065	// type used to type-check the validity of return statements within the
4066	// method body is a pointer to the type of the class being implemented.
4067	RelatedRetType = Context.getObjCInterfaceType(Decl: MD->getClassInterface());
4068	RelatedRetType = Context.getObjCObjectPointerType(OIT: RelatedRetType);
4069	}
4070	} else // If we don't have a function/method context, bail.
4071	return StmtError();
4072
4073	if (RetValExp) {
4074	const auto *ATy = dyn_cast<ArrayType>(Val: RetValExp->getType());
4075	if (ATy && ATy->getElementType().isWebAssemblyReferenceType()) {
4076	Diag(ReturnLoc, diag::err_wasm_table_art) << 1;
4077	return StmtError();
4078	}
4079	}
4080
4081	// C++1z: discarded return statements are not considered when deducing a
4082	// return type.
4083	if (ExprEvalContexts.back().isDiscardedStatementContext() &&
4084	FnRetType->getContainedAutoType()) {
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	return ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4093	/* NRVOCandidate=*/nullptr);
4094	}
4095
4096	// FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
4097	// deduction.
4098	if (getLangOpts().CPlusPlus14) {
4099	if (AutoType *AT = FnRetType->getContainedAutoType()) {
4100	FunctionDecl *FD = cast<FunctionDecl>(Val: CurContext);
4101	// If we've already decided this function is invalid, e.g. because
4102	// we saw a `return` whose expression had an error, don't keep
4103	// trying to deduce its return type.
4104	// (Some return values may be needlessly wrapped in RecoveryExpr).
4105	if (FD->isInvalidDecl() ||
4106	DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetExpr: RetValExp, AT)) {
4107	FD->setInvalidDecl();
4108	if (!AllowRecovery)
4109	return StmtError();
4110	// The deduction failure is diagnosed and marked, try to recover.
4111	if (RetValExp) {
4112	// Wrap return value with a recovery expression of the previous type.
4113	// If no deduction yet, use DependentTy.
4114	auto Recovery = CreateRecoveryExpr(
4115	Begin: RetValExp->getBeginLoc(), End: RetValExp->getEndLoc(), SubExprs: RetValExp,
4116	T: AT->isDeduced() ? FnRetType : QualType());
4117	if (Recovery.isInvalid())
4118	return StmtError();
4119	RetValExp = Recovery.get();
4120	} else {
4121	// Nothing to do: a ReturnStmt with no value is fine recovery.
4122	}
4123	} else {
4124	FnRetType = FD->getReturnType();
4125	}
4126	}
4127	}
4128	const VarDecl *NRVOCandidate = getCopyElisionCandidate(Info&: NRInfo, ReturnType: FnRetType);
4129
4130	bool HasDependentReturnType = FnRetType->isDependentType();
4131
4132	ReturnStmt *Result = nullptr;
4133	if (FnRetType->isVoidType()) {
4134	if (RetValExp) {
4135	if (auto *ILE = dyn_cast<InitListExpr>(Val: RetValExp)) {
4136	// We simply never allow init lists as the return value of void
4137	// functions. This is compatible because this was never allowed before,
4138	// so there's no legacy code to deal with.
4139	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4140	int FunctionKind = 0;
4141	if (isa<ObjCMethodDecl>(Val: CurDecl))
4142	FunctionKind = 1;
4143	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4144	FunctionKind = 2;
4145	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4146	FunctionKind = 3;
4147
4148	Diag(ReturnLoc, diag::err_return_init_list)
4149	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4150
4151	// Preserve the initializers in the AST.
4152	RetValExp = AllowRecovery
4153	? CreateRecoveryExpr(Begin: ILE->getLBraceLoc(),
4154	End: ILE->getRBraceLoc(), SubExprs: ILE->inits())
4155	.get()
4156	: nullptr;
4157	} else if (!RetValExp->isTypeDependent()) {
4158	// C99 6.8.6.4p1 (ext_ since GCC warns)
4159	unsigned D = diag::ext_return_has_expr;
4160	if (RetValExp->getType()->isVoidType()) {
4161	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4162	if (isa<CXXConstructorDecl>(CurDecl) ||
4163	isa<CXXDestructorDecl>(CurDecl))
4164	D = diag::err_ctor_dtor_returns_void;
4165	else
4166	D = diag::ext_return_has_void_expr;
4167	}
4168	else {
4169	ExprResult Result = RetValExp;
4170	Result = IgnoredValueConversions(E: Result.get());
4171	if (Result.isInvalid())
4172	return StmtError();
4173	RetValExp = Result.get();
4174	RetValExp = ImpCastExprToType(E: RetValExp,
4175	Type: Context.VoidTy, CK: CK_ToVoid).get();
4176	}
4177	// return of void in constructor/destructor is illegal in C++.
4178	if (D == diag::err_ctor_dtor_returns_void) {
4179	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4180	Diag(ReturnLoc, D) << CurDecl << isa<CXXDestructorDecl>(Val: CurDecl)
4181	<< RetValExp->getSourceRange();
4182	}
4183	// return (some void expression); is legal in C++.
4184	else if (D != diag::ext_return_has_void_expr ||
4185	!getLangOpts().CPlusPlus) {
4186	NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
4187
4188	int FunctionKind = 0;
4189	if (isa<ObjCMethodDecl>(Val: CurDecl))
4190	FunctionKind = 1;
4191	else if (isa<CXXConstructorDecl>(Val: CurDecl))
4192	FunctionKind = 2;
4193	else if (isa<CXXDestructorDecl>(Val: CurDecl))
4194	FunctionKind = 3;
4195
4196	Diag(ReturnLoc, D)
4197	<< CurDecl << FunctionKind << RetValExp->getSourceRange();
4198	}
4199	}
4200
4201	if (RetValExp) {
4202	ExprResult ER =
4203	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4204	if (ER.isInvalid())
4205	return StmtError();
4206	RetValExp = ER.get();
4207	}
4208	}
4209
4210	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp,
4211	/* NRVOCandidate=*/nullptr);
4212	} else if (!RetValExp && !HasDependentReturnType) {
4213	FunctionDecl *FD = getCurFunctionDecl();
4214
4215	if ((FD && FD->isInvalidDecl()) || FnRetType->containsErrors()) {
4216	// The intended return type might have been "void", so don't warn.
4217	} else if (getLangOpts().CPlusPlus11 && FD && FD->isConstexpr()) {
4218	// C++11 [stmt.return]p2
4219	Diag(ReturnLoc, diag::err_constexpr_return_missing_expr)
4220	<< FD << FD->isConsteval();
4221	FD->setInvalidDecl();
4222	} else {
4223	// C99 6.8.6.4p1 (ext_ since GCC warns)
4224	// C90 6.6.6.4p4
4225	unsigned DiagID = getLangOpts().C99 ? diag::ext_return_missing_expr
4226	: diag::warn_return_missing_expr;
4227	// Note that at this point one of getCurFunctionDecl() or
4228	// getCurMethodDecl() must be non-null (see above).
4229	assert((getCurFunctionDecl() || getCurMethodDecl()) &&
4230	"Not in a FunctionDecl or ObjCMethodDecl?");
4231	bool IsMethod = FD == nullptr;
4232	const NamedDecl *ND =
4233	IsMethod ? cast<NamedDecl>(Val: getCurMethodDecl()) : cast<NamedDecl>(Val: FD);
4234	Diag(ReturnLoc, DiagID) << ND << IsMethod;
4235	}
4236
4237	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, /* RetExpr=*/E: nullptr,
4238	/* NRVOCandidate=*/nullptr);
4239	} else {
4240	assert(RetValExp || HasDependentReturnType);
4241	QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
4242
4243	// C99 6.8.6.4p3(136): The return statement is not an assignment. The
4244	// overlap restriction of subclause 6.5.16.1 does not apply to the case of
4245	// function return.
4246
4247	// In C++ the return statement is handled via a copy initialization,
4248	// the C version of which boils down to CheckSingleAssignmentConstraints.
4249	if (!HasDependentReturnType && !RetValExp->isTypeDependent()) {
4250	// we have a non-void function with an expression, continue checking
4251	InitializedEntity Entity =
4252	InitializedEntity::InitializeResult(ReturnLoc, Type: RetType);
4253	ExprResult Res = PerformMoveOrCopyInitialization(
4254	Entity, NRInfo, Value: RetValExp, SupressSimplerImplicitMoves);
4255	if (Res.isInvalid() && AllowRecovery)
4256	Res = CreateRecoveryExpr(Begin: RetValExp->getBeginLoc(),
4257	End: RetValExp->getEndLoc(), SubExprs: RetValExp, T: RetType);
4258	if (Res.isInvalid()) {
4259	// FIXME: Clean up temporaries here anyway?
4260	return StmtError();
4261	}
4262	RetValExp = Res.getAs<Expr>();
4263
4264	// If we have a related result type, we need to implicitly
4265	// convert back to the formal result type. We can't pretend to
4266	// initialize the result again --- we might end double-retaining
4267	// --- so instead we initialize a notional temporary.
4268	if (!RelatedRetType.isNull()) {
4269	Entity = InitializedEntity::InitializeRelatedResult(MD: getCurMethodDecl(),
4270	Type: FnRetType);
4271	Res = PerformCopyInitialization(Entity, EqualLoc: ReturnLoc, Init: RetValExp);
4272	if (Res.isInvalid()) {
4273	// FIXME: Clean up temporaries here anyway?
4274	return StmtError();
4275	}
4276	RetValExp = Res.getAs<Expr>();
4277	}
4278
4279	CheckReturnValExpr(RetValExp, lhsType: FnRetType, ReturnLoc, isObjCMethod, Attrs,
4280	FD: getCurFunctionDecl());
4281	}
4282
4283	if (RetValExp) {
4284	ExprResult ER =
4285	ActOnFinishFullExpr(Expr: RetValExp, CC: ReturnLoc, /*DiscardedValue*/ false);
4286	if (ER.isInvalid())
4287	return StmtError();
4288	RetValExp = ER.get();
4289	}
4290	Result = ReturnStmt::Create(Ctx: Context, RL: ReturnLoc, E: RetValExp, NRVOCandidate);
4291	}
4292
4293	// If we need to check for the named return value optimization, save the
4294	// return statement in our scope for later processing.
4295	if (Result->getNRVOCandidate())
4296	FunctionScopes.back()->Returns.push_back(Elt: Result);
4297
4298	if (FunctionScopes.back()->FirstReturnLoc.isInvalid())
4299	FunctionScopes.back()->FirstReturnLoc = ReturnLoc;
4300
4301	return Result;
4302	}
4303
4304	StmtResult
4305	Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
4306	SourceLocation RParen, Decl *Parm,
4307	Stmt *Body) {
4308	VarDecl *Var = cast_or_null<VarDecl>(Val: Parm);
4309	if (Var && Var->isInvalidDecl())
4310	return StmtError();
4311
4312	return new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body);
4313	}
4314
4315	StmtResult
4316	Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) {
4317	return new (Context) ObjCAtFinallyStmt(AtLoc, Body);
4318	}
4319
4320	StmtResult
4321	Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try,
4322	MultiStmtArg CatchStmts, Stmt *Finally) {
4323	if (!getLangOpts().ObjCExceptions)
4324	Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try";
4325
4326	// Objective-C try is incompatible with SEH __try.
4327	sema::FunctionScopeInfo *FSI = getCurFunction();
4328	if (FSI->FirstSEHTryLoc.isValid()) {
4329	Diag(AtLoc, diag::err_mixing_cxx_try_seh_try) << 1;
4330	Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
4331	}
4332
4333	FSI->setHasObjCTry(AtLoc);
4334	unsigned NumCatchStmts = CatchStmts.size();
4335	return ObjCAtTryStmt::Create(Context, atTryLoc: AtLoc, atTryStmt: Try, CatchStmts: CatchStmts.data(),
4336	NumCatchStmts, atFinallyStmt: Finally);
4337	}
4338
4339	StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
4340	if (Throw) {
4341	ExprResult Result = DefaultLvalueConversion(E: Throw);
4342	if (Result.isInvalid())
4343	return StmtError();
4344
4345	Result = ActOnFinishFullExpr(Expr: Result.get(), /*DiscardedValue*/ false);
4346	if (Result.isInvalid())
4347	return StmtError();
4348	Throw = Result.get();
4349
4350	QualType ThrowType = Throw->getType();
4351	// Make sure the expression type is an ObjC pointer or "void *".
4352	if (!ThrowType->isDependentType() &&
4353	!ThrowType->isObjCObjectPointerType()) {
4354	const PointerType *PT = ThrowType->getAs<PointerType>();
4355	if (!PT || !PT->getPointeeType()->isVoidType())
4356	return StmtError(Diag(AtLoc, diag::err_objc_throw_expects_object)
4357	<< Throw->getType() << Throw->getSourceRange());
4358	}
4359	}
4360
4361	return new (Context) ObjCAtThrowStmt(AtLoc, Throw);
4362	}
4363
4364	StmtResult
4365	Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw,
4366	Scope *CurScope) {
4367	if (!getLangOpts().ObjCExceptions)
4368	Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw";
4369
4370	if (!Throw) {
4371	// @throw without an expression designates a rethrow (which must occur
4372	// in the context of an @catch clause).
4373	Scope *AtCatchParent = CurScope;
4374	while (AtCatchParent && !AtCatchParent->isAtCatchScope())
4375	AtCatchParent = AtCatchParent->getParent();
4376	if (!AtCatchParent)
4377	return StmtError(Diag(AtLoc, diag::err_rethrow_used_outside_catch));
4378	}
4379	return BuildObjCAtThrowStmt(AtLoc, Throw);
4380	}
4381
4382	ExprResult
4383	Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
4384	ExprResult result = DefaultLvalueConversion(E: operand);
4385	if (result.isInvalid())
4386	return ExprError();
4387	operand = result.get();
4388
4389	// Make sure the expression type is an ObjC pointer or "void *".
4390	QualType type = operand->getType();
4391	if (!type->isDependentType() &&
4392	!type->isObjCObjectPointerType()) {
4393	const PointerType *pointerType = type->getAs<PointerType>();
4394	if (!pointerType || !pointerType->getPointeeType()->isVoidType()) {
4395	if (getLangOpts().CPlusPlus) {
4396	if (RequireCompleteType(atLoc, type,
4397	diag::err_incomplete_receiver_type))
4398	return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4399	<< type << operand->getSourceRange();
4400
4401	ExprResult result = PerformContextuallyConvertToObjCPointer(From: operand);
4402	if (result.isInvalid())
4403	return ExprError();
4404	if (!result.isUsable())
4405	return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4406	<< type << operand->getSourceRange();
4407
4408	operand = result.get();
4409	} else {
4410	return Diag(atLoc, diag::err_objc_synchronized_expects_object)
4411	<< type << operand->getSourceRange();
4412	}
4413	}
4414	}
4415
4416	// The operand to @synchronized is a full-expression.
4417	return ActOnFinishFullExpr(Expr: operand, /*DiscardedValue*/ false);
4418	}
4419
4420	StmtResult
4421	Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr,
4422	Stmt *SyncBody) {
4423	// We can't jump into or indirect-jump out of a @synchronized block.
4424	setFunctionHasBranchProtectedScope();
4425	return new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody);
4426	}
4427
4428	/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
4429	/// and creates a proper catch handler from them.
4430	StmtResult
4431	Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl,
4432	Stmt *HandlerBlock) {
4433	// There's nothing to test that ActOnExceptionDecl didn't already test.
4434	return new (Context)
4435	CXXCatchStmt(CatchLoc, cast_or_null<VarDecl>(Val: ExDecl), HandlerBlock);
4436	}
4437
4438	StmtResult
4439	Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) {
4440	setFunctionHasBranchProtectedScope();
4441	return new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body);
4442	}
4443
4444	namespace {
4445	class CatchHandlerType {
4446	QualType QT;
4447	LLVM_PREFERRED_TYPE(bool)
4448	unsigned IsPointer : 1;
4449
4450	// This is a special constructor to be used only with DenseMapInfo's
4451	// getEmptyKey() and getTombstoneKey() functions.
4452	friend struct llvm::DenseMapInfo<CatchHandlerType>;
4453	enum Unique { ForDenseMap };
4454	CatchHandlerType(QualType QT, Unique) : QT(QT), IsPointer(false) {}
4455
4456	public:
4457	/// Used when creating a CatchHandlerType from a handler type; will determine
4458	/// whether the type is a pointer or reference and will strip off the top
4459	/// level pointer and cv-qualifiers.
4460	CatchHandlerType(QualType Q) : QT(Q), IsPointer(false) {
4461	if (QT->isPointerType())
4462	IsPointer = true;
4463
4464	QT = QT.getUnqualifiedType();
4465	if (IsPointer || QT->isReferenceType())
4466	QT = QT->getPointeeType();
4467	}
4468
4469	/// Used when creating a CatchHandlerType from a base class type; pretends the
4470	/// type passed in had the pointer qualifier, does not need to get an
4471	/// unqualified type.
4472	CatchHandlerType(QualType QT, bool IsPointer)
4473	: QT(QT), IsPointer(IsPointer) {}
4474
4475	QualType underlying() const { return QT; }
4476	bool isPointer() const { return IsPointer; }
4477
4478	friend bool operator==(const CatchHandlerType &LHS,
4479	const CatchHandlerType &RHS) {
4480	// If the pointer qualification does not match, we can return early.
4481	if (LHS.IsPointer != RHS.IsPointer)
4482	return false;
4483	// Otherwise, check the underlying type without cv-qualifiers.
4484	return LHS.QT == RHS.QT;
4485	}
4486	};
4487	} // namespace
4488
4489	namespace llvm {
4490	template <> struct DenseMapInfo<CatchHandlerType> {
4491	static CatchHandlerType getEmptyKey() {
4492	return CatchHandlerType(DenseMapInfo<QualType>::getEmptyKey(),
4493	CatchHandlerType::ForDenseMap);
4494	}
4495
4496	static CatchHandlerType getTombstoneKey() {
4497	return CatchHandlerType(DenseMapInfo<QualType>::getTombstoneKey(),
4498	CatchHandlerType::ForDenseMap);
4499	}
4500
4501	static unsigned getHashValue(const CatchHandlerType &Base) {
4502	return DenseMapInfo<QualType>::getHashValue(Val: Base.underlying());
4503	}
4504
4505	static bool isEqual(const CatchHandlerType &LHS,
4506	const CatchHandlerType &RHS) {
4507	return LHS == RHS;
4508	}
4509	};
4510	}
4511
4512	namespace {
4513	class CatchTypePublicBases {
4514	const llvm::DenseMap<QualType, CXXCatchStmt *> &TypesToCheck;
4515
4516	CXXCatchStmt *FoundHandler;
4517	QualType FoundHandlerType;
4518	QualType TestAgainstType;
4519
4520	public:
4521	CatchTypePublicBases(const llvm::DenseMap<QualType, CXXCatchStmt *> &T,
4522	QualType QT)
4523	: TypesToCheck(T), FoundHandler(nullptr), TestAgainstType(QT) {}
4524
4525	CXXCatchStmt *getFoundHandler() const { return FoundHandler; }
4526	QualType getFoundHandlerType() const { return FoundHandlerType; }
4527
4528	bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
4529	if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
4530	QualType Check = S->getType().getCanonicalType();
4531	const auto &M = TypesToCheck;
4532	auto I = M.find(Val: Check);
4533	if (I != M.end()) {
4534	// We're pretty sure we found what we need to find. However, we still
4535	// need to make sure that we properly compare for pointers and
4536	// references, to handle cases like:
4537	//
4538	// } catch (Base *b) {
4539	// } catch (Derived &d) {
4540	// }
4541	//
4542	// where there is a qualification mismatch that disqualifies this
4543	// handler as a potential problem.
4544	if (I->second->getCaughtType()->isPointerType() ==
4545	TestAgainstType->isPointerType()) {
4546	FoundHandler = I->second;
4547	FoundHandlerType = Check;
4548	return true;
4549	}
4550	}
4551	}
4552	return false;
4553	}
4554	};
4555	}
4556
4557	/// ActOnCXXTryBlock - Takes a try compound-statement and a number of
4558	/// handlers and creates a try statement from them.
4559	StmtResult Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock,
4560	ArrayRef<Stmt *> Handlers) {
4561	const llvm::Triple &T = Context.getTargetInfo().getTriple();
4562	const bool IsOpenMPGPUTarget =
4563	getLangOpts().OpenMPIsTargetDevice && (T.isNVPTX() || T.isAMDGCN());
4564	// Don't report an error if 'try' is used in system headers or in an OpenMP
4565	// target region compiled for a GPU architecture.
4566	if (!IsOpenMPGPUTarget && !getLangOpts().CXXExceptions &&
4567	!getSourceManager().isInSystemHeader(Loc: TryLoc) && !getLangOpts().CUDA) {
4568	// Delay error emission for the OpenMP device code.
4569	targetDiag(TryLoc, diag::err_exceptions_disabled) << "try";
4570	}
4571
4572	// In OpenMP target regions, we assume that catch is never reached on GPU
4573	// targets.
4574	if (IsOpenMPGPUTarget)
4575	targetDiag(TryLoc, diag::warn_try_not_valid_on_target) << T.str();
4576
4577	// Exceptions aren't allowed in CUDA device code.
4578	if (getLangOpts().CUDA)
4579	CUDA().DiagIfDeviceCode(TryLoc, diag::err_cuda_device_exceptions)
4580	<< "try" << llvm::to_underlying(CUDA().CurrentTarget());
4581
4582	if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
4583	Diag(TryLoc, diag::err_omp_simd_region_cannot_use_stmt) << "try";
4584
4585	sema::FunctionScopeInfo *FSI = getCurFunction();
4586
4587	// C++ try is incompatible with SEH __try.
4588	if (!getLangOpts().Borland && FSI->FirstSEHTryLoc.isValid()) {
4589	Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << 0;
4590	Diag(FSI->FirstSEHTryLoc, diag::note_conflicting_try_here) << "'__try'";
4591	}
4592
4593	const unsigned NumHandlers = Handlers.size();
4594	assert(!Handlers.empty() &&
4595	"The parser shouldn't call this if there are no handlers.");
4596
4597	llvm::DenseMap<QualType, CXXCatchStmt *> HandledBaseTypes;
4598	llvm::DenseMap<CatchHandlerType, CXXCatchStmt *> HandledTypes;
4599	for (unsigned i = 0; i < NumHandlers; ++i) {
4600	CXXCatchStmt *H = cast<CXXCatchStmt>(Val: Handlers[i]);
4601
4602	// Diagnose when the handler is a catch-all handler, but it isn't the last
4603	// handler for the try block. [except.handle]p5. Also, skip exception
4604	// declarations that are invalid, since we can't usefully report on them.
4605	if (!H->getExceptionDecl()) {
4606	if (i < NumHandlers - 1)
4607	return StmtError(Diag(H->getBeginLoc(), diag::err_early_catch_all));
4608	continue;
4609	} else if (H->getExceptionDecl()->isInvalidDecl())
4610	continue;
4611
4612	// Walk the type hierarchy to diagnose when this type has already been
4613	// handled (duplication), or cannot be handled (derivation inversion). We
4614	// ignore top-level cv-qualifiers, per [except.handle]p3
4615	CatchHandlerType HandlerCHT = H->getCaughtType().getCanonicalType();
4616
4617	// We can ignore whether the type is a reference or a pointer; we need the
4618	// underlying declaration type in order to get at the underlying record
4619	// decl, if there is one.
4620	QualType Underlying = HandlerCHT.underlying();
4621	if (auto *RD = Underlying->getAsCXXRecordDecl()) {
4622	if (!RD->hasDefinition())
4623	continue;
4624	// Check that none of the public, unambiguous base classes are in the
4625	// map ([except.handle]p1). Give the base classes the same pointer
4626	// qualification as the original type we are basing off of. This allows
4627	// comparison against the handler type using the same top-level pointer
4628	// as the original type.
4629	CXXBasePaths Paths;
4630	Paths.setOrigin(RD);
4631	CatchTypePublicBases CTPB(HandledBaseTypes,
4632	H->getCaughtType().getCanonicalType());
4633	if (RD->lookupInBases(BaseMatches: CTPB, Paths)) {
4634	const CXXCatchStmt *Problem = CTPB.getFoundHandler();
4635	if (!Paths.isAmbiguous(
4636	BaseType: CanQualType::CreateUnsafe(Other: CTPB.getFoundHandlerType()))) {
4637	Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4638	diag::warn_exception_caught_by_earlier_handler)
4639	<< H->getCaughtType();
4640	Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4641	diag::note_previous_exception_handler)
4642	<< Problem->getCaughtType();
4643	}
4644	}
4645	// Strip the qualifiers here because we're going to be comparing this
4646	// type to the base type specifiers of a class, which are ignored in a
4647	// base specifier per [class.derived.general]p2.
4648	HandledBaseTypes[Underlying.getUnqualifiedType()] = H;
4649	}
4650
4651	// Add the type the list of ones we have handled; diagnose if we've already
4652	// handled it.
4653	auto R = HandledTypes.insert(
4654	std::make_pair(x: H->getCaughtType().getCanonicalType(), y&: H));
4655	if (!R.second) {
4656	const CXXCatchStmt *Problem = R.first->second;
4657	Diag(H->getExceptionDecl()->getTypeSpecStartLoc(),
4658	diag::warn_exception_caught_by_earlier_handler)
4659	<< H->getCaughtType();
4660	Diag(Problem->getExceptionDecl()->getTypeSpecStartLoc(),
4661	diag::note_previous_exception_handler)
4662	<< Problem->getCaughtType();
4663	}
4664	}
4665
4666	FSI->setHasCXXTry(TryLoc);
4667
4668	return CXXTryStmt::Create(C: Context, tryLoc: TryLoc, tryBlock: cast<CompoundStmt>(Val: TryBlock),
4669	handlers: Handlers);
4670	}
4671
4672	StmtResult Sema::ActOnSEHTryBlock(bool IsCXXTry, SourceLocation TryLoc,
4673	Stmt *TryBlock, Stmt *Handler) {
4674	assert(TryBlock && Handler);
4675
4676	sema::FunctionScopeInfo *FSI = getCurFunction();
4677
4678	// SEH __try is incompatible with C++ try. Borland appears to support this,
4679	// however.
4680	if (!getLangOpts().Borland) {
4681	if (FSI->FirstCXXOrObjCTryLoc.isValid()) {
4682	Diag(TryLoc, diag::err_mixing_cxx_try_seh_try) << FSI->FirstTryType;
4683	Diag(FSI->FirstCXXOrObjCTryLoc, diag::note_conflicting_try_here)
4684	<< (FSI->FirstTryType == sema::FunctionScopeInfo::TryLocIsCXX
4685	? "'try'"
4686	: "'@try'");
4687	}
4688	}
4689
4690	FSI->setHasSEHTry(TryLoc);
4691
4692	// Reject __try in Obj-C methods, blocks, and captured decls, since we don't
4693	// track if they use SEH.
4694	DeclContext *DC = CurContext;
4695	while (DC && !DC->isFunctionOrMethod())
4696	DC = DC->getParent();
4697	FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Val: DC);
4698	if (FD)
4699	FD->setUsesSEHTry(true);
4700	else
4701	Diag(TryLoc, diag::err_seh_try_outside_functions);
4702
4703	// Reject __try on unsupported targets.
4704	if (!Context.getTargetInfo().isSEHTrySupported())
4705	Diag(TryLoc, diag::err_seh_try_unsupported);
4706
4707	return SEHTryStmt::Create(C: Context, isCXXTry: IsCXXTry, TryLoc, TryBlock, Handler);
4708	}
4709
4710	StmtResult Sema::ActOnSEHExceptBlock(SourceLocation Loc, Expr *FilterExpr,
4711	Stmt *Block) {
4712	assert(FilterExpr && Block);
4713	QualType FTy = FilterExpr->getType();
4714	if (!FTy->isIntegerType() && !FTy->isDependentType()) {
4715	return StmtError(
4716	Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral)
4717	<< FTy);
4718	}
4719	return SEHExceptStmt::Create(C: Context, ExceptLoc: Loc, FilterExpr, Block);
4720	}
4721
4722	void Sema::ActOnStartSEHFinallyBlock() {
4723	CurrentSEHFinally.push_back(Elt: CurScope);
4724	}
4725
4726	void Sema::ActOnAbortSEHFinallyBlock() {
4727	CurrentSEHFinally.pop_back();
4728	}
4729
4730	StmtResult Sema::ActOnFinishSEHFinallyBlock(SourceLocation Loc, Stmt *Block) {
4731	assert(Block);
4732	CurrentSEHFinally.pop_back();
4733	return SEHFinallyStmt::Create(C: Context, FinallyLoc: Loc, Block);
4734	}
4735
4736	StmtResult
4737	Sema::ActOnSEHLeaveStmt(SourceLocation Loc, Scope *CurScope) {
4738	Scope *SEHTryParent = CurScope;
4739	while (SEHTryParent && !SEHTryParent->isSEHTryScope())
4740	SEHTryParent = SEHTryParent->getParent();
4741	if (!SEHTryParent)
4742	return StmtError(Diag(Loc, diag::err_ms___leave_not_in___try));
4743	CheckJumpOutOfSEHFinally(S&: *this, Loc, DestScope: *SEHTryParent);
4744
4745	return new (Context) SEHLeaveStmt(Loc);
4746	}
4747
4748	StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc,
4749	bool IsIfExists,
4750	NestedNameSpecifierLoc QualifierLoc,
4751	DeclarationNameInfo NameInfo,
4752	Stmt *Nested)
4753	{
4754	return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists,
4755	QualifierLoc, NameInfo,
4756	cast<CompoundStmt>(Val: Nested));
4757	}
4758
4759
4760	StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc,
4761	bool IsIfExists,
4762	CXXScopeSpec &SS,
4763	UnqualifiedId &Name,
4764	Stmt *Nested) {
4765	return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists,
4766	QualifierLoc: SS.getWithLocInContext(Context),
4767	NameInfo: GetNameFromUnqualifiedId(Name),
4768	Nested);
4769	}
4770
4771	RecordDecl*
4772	Sema::CreateCapturedStmtRecordDecl(CapturedDecl *&CD, SourceLocation Loc,
4773	unsigned NumParams) {
4774	DeclContext *DC = CurContext;
4775	while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
4776	DC = DC->getParent();
4777
4778	RecordDecl *RD = nullptr;
4779	if (getLangOpts().CPlusPlus)
4780	RD = CXXRecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4781	/*Id=*/nullptr);
4782	else
4783	RD = RecordDecl::Create(C: Context, TK: TagTypeKind::Struct, DC, StartLoc: Loc, IdLoc: Loc,
4784	/*Id=*/nullptr);
4785
4786	RD->setCapturedRecord();
4787	DC->addDecl(RD);
4788	RD->setImplicit();
4789	RD->startDefinition();
4790
4791	assert(NumParams > 0 && "CapturedStmt requires context parameter");
4792	CD = CapturedDecl::Create(C&: Context, DC: CurContext, NumParams);
4793	DC->addDecl(CD);
4794	return RD;
4795	}
4796
4797	static bool
4798	buildCapturedStmtCaptureList(Sema &S, CapturedRegionScopeInfo *RSI,
4799	SmallVectorImpl<CapturedStmt::Capture> &Captures,
4800	SmallVectorImpl<Expr *> &CaptureInits) {
4801	for (const sema::Capture &Cap : RSI->Captures) {
4802	if (Cap.isInvalid())
4803	continue;
4804
4805	// Form the initializer for the capture.
4806	ExprResult Init = S.BuildCaptureInit(Capture: Cap, ImplicitCaptureLoc: Cap.getLocation(),
4807	IsOpenMPMapping: RSI->CapRegionKind == CR_OpenMP);
4808
4809	// FIXME: Bail out now if the capture is not used and the initializer has
4810	// no side-effects.
4811
4812	// Create a field for this capture.
4813	FieldDecl *Field = S.BuildCaptureField(RD: RSI->TheRecordDecl, Capture: Cap);
4814
4815	// Add the capture to our list of captures.
4816	if (Cap.isThisCapture()) {
4817	Captures.push_back(Elt: CapturedStmt::Capture(Cap.getLocation(),
4818	CapturedStmt::VCK_This));
4819	} else if (Cap.isVLATypeCapture()) {
4820	Captures.push_back(
4821	Elt: CapturedStmt::Capture(Cap.getLocation(), CapturedStmt::VCK_VLAType));
4822	} else {
4823	assert(Cap.isVariableCapture() && "unknown kind of capture");
4824
4825	if (S.getLangOpts().OpenMP && RSI->CapRegionKind == CR_OpenMP)
4826	S.OpenMP().setOpenMPCaptureKind(FD: Field, D: Cap.getVariable(),
4827	Level: RSI->OpenMPLevel);
4828
4829	Captures.push_back(Elt: CapturedStmt::Capture(
4830	Cap.getLocation(),
4831	Cap.isReferenceCapture() ? CapturedStmt::VCK_ByRef
4832	: CapturedStmt::VCK_ByCopy,
4833	cast<VarDecl>(Val: Cap.getVariable())));
4834	}
4835	CaptureInits.push_back(Elt: Init.get());
4836	}
4837	return false;
4838	}
4839
4840	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4841	CapturedRegionKind Kind,
4842	unsigned NumParams) {
4843	CapturedDecl *CD = nullptr;
4844	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams);
4845
4846	// Build the context parameter
4847	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4848	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4849	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD));
4850	auto *Param =
4851	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4852	ParamKind: ImplicitParamKind::CapturedContext);
4853	DC->addDecl(D: Param);
4854
4855	CD->setContextParam(i: 0, P: Param);
4856
4857	// Enter the capturing scope for this captured region.
4858	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind);
4859
4860	if (CurScope)
4861	PushDeclContext(CurScope, CD);
4862	else
4863	CurContext = CD;
4864
4865	PushExpressionEvaluationContext(
4866	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4867	ExprEvalContexts.back().InImmediateEscalatingFunctionContext = false;
4868	}
4869
4870	void Sema::ActOnCapturedRegionStart(SourceLocation Loc, Scope *CurScope,
4871	CapturedRegionKind Kind,
4872	ArrayRef<CapturedParamNameType> Params,
4873	unsigned OpenMPCaptureLevel) {
4874	CapturedDecl *CD = nullptr;
4875	RecordDecl *RD = CreateCapturedStmtRecordDecl(CD, Loc, NumParams: Params.size());
4876
4877	// Build the context parameter
4878	DeclContext *DC = CapturedDecl::castToDeclContext(D: CD);
4879	bool ContextIsFound = false;
4880	unsigned ParamNum = 0;
4881	for (ArrayRef<CapturedParamNameType>::iterator I = Params.begin(),
4882	E = Params.end();
4883	I != E; ++I, ++ParamNum) {
4884	if (I->second.isNull()) {
4885	assert(!ContextIsFound &&
4886	"null type has been found already for '__context' parameter");
4887	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4888	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD))
4889	.withConst()
4890	.withRestrict();
4891	auto *Param =
4892	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4893	ParamKind: ImplicitParamKind::CapturedContext);
4894	DC->addDecl(D: Param);
4895	CD->setContextParam(i: ParamNum, P: Param);
4896	ContextIsFound = true;
4897	} else {
4898	IdentifierInfo *ParamName = &Context.Idents.get(Name: I->first);
4899	auto *Param =
4900	ImplicitParamDecl::Create(Context, DC, Loc, ParamName, I->second,
4901	ImplicitParamKind::CapturedContext);
4902	DC->addDecl(D: Param);
4903	CD->setParam(i: ParamNum, P: Param);
4904	}
4905	}
4906	assert(ContextIsFound && "no null type for '__context' parameter");
4907	if (!ContextIsFound) {
4908	// Add __context implicitly if it is not specified.
4909	IdentifierInfo *ParamName = &Context.Idents.get(Name: "__context");
4910	QualType ParamType = Context.getPointerType(T: Context.getTagDeclType(RD));
4911	auto *Param =
4912	ImplicitParamDecl::Create(C&: Context, DC, IdLoc: Loc, Id: ParamName, T: ParamType,
4913	ParamKind: ImplicitParamKind::CapturedContext);
4914	DC->addDecl(D: Param);
4915	CD->setContextParam(i: ParamNum, P: Param);
4916	}
4917	// Enter the capturing scope for this captured region.
4918	PushCapturedRegionScope(RegionScope: CurScope, CD, RD, K: Kind, OpenMPCaptureLevel);
4919
4920	if (CurScope)
4921	PushDeclContext(CurScope, CD);
4922	else
4923	CurContext = CD;
4924
4925	PushExpressionEvaluationContext(
4926	NewContext: ExpressionEvaluationContext::PotentiallyEvaluated);
4927	}
4928
4929	void Sema::ActOnCapturedRegionError() {
4930	DiscardCleanupsInEvaluationContext();
4931	PopExpressionEvaluationContext();
4932	PopDeclContext();
4933	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4934	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4935
4936	RecordDecl *Record = RSI->TheRecordDecl;
4937	Record->setInvalidDecl();
4938
4939	SmallVector<Decl*, 4> Fields(Record->fields());
4940	ActOnFields(/*Scope=*/S: nullptr, RecLoc: Record->getLocation(), TagDecl: Record, Fields,
4941	LBrac: SourceLocation(), RBrac: SourceLocation(), AttrList: ParsedAttributesView());
4942	}
4943
4944	StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
4945	// Leave the captured scope before we start creating captures in the
4946	// enclosing scope.
4947	DiscardCleanupsInEvaluationContext();
4948	PopExpressionEvaluationContext();
4949	PopDeclContext();
4950	PoppedFunctionScopePtr ScopeRAII = PopFunctionScopeInfo();
4951	CapturedRegionScopeInfo *RSI = cast<CapturedRegionScopeInfo>(Val: ScopeRAII.get());
4952
4953	SmallVector<CapturedStmt::Capture, 4> Captures;
4954	SmallVector<Expr *, 4> CaptureInits;
4955	if (buildCapturedStmtCaptureList(S&: *this, RSI, Captures, CaptureInits))
4956	return StmtError();
4957
4958	CapturedDecl *CD = RSI->TheCapturedDecl;
4959	RecordDecl *RD = RSI->TheRecordDecl;
4960
4961	CapturedStmt *Res = CapturedStmt::Create(
4962	Context: getASTContext(), S, Kind: static_cast<CapturedRegionKind>(RSI->CapRegionKind),
4963	Captures, CaptureInits, CD, RD);
4964
4965	CD->setBody(Res->getCapturedStmt());
4966	RD->completeDefinition();
4967
4968	return Res;
4969	}
4970