1 //===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements semantic analysis for cast expressions, including
11 // 1) C-style casts like '(int) x'
12 // 2) C++ functional casts like 'int(x)'
13 // 3) C++ named casts like 'static_cast<int>(x)'
15 //===----------------------------------------------------------------------===//
17 #include "clang/Sema/SemaInternal.h"
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/CXXInheritance.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
22 #include "clang/AST/RecordLayout.h"
23 #include "clang/Basic/PartialDiagnostic.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Lex/Preprocessor.h"
26 #include "clang/Sema/Initialization.h"
27 #include "llvm/ADT/SmallVector.h"
29 using namespace clang;
34 TC_NotApplicable, ///< The cast method is not applicable.
35 TC_Success, ///< The cast method is appropriate and successful.
36 TC_Failed ///< The cast method is appropriate, but failed. A
37 ///< diagnostic has been emitted.
41 CT_Const, ///< const_cast
42 CT_Static, ///< static_cast
43 CT_Reinterpret, ///< reinterpret_cast
44 CT_Dynamic, ///< dynamic_cast
45 CT_CStyle, ///< (Type)expr
46 CT_Functional ///< Type(expr)
50 struct CastOperation {
51 CastOperation(Sema &S, QualType destType, ExprResult src)
52 : Self(S), SrcExpr(src), DestType(destType),
53 ResultType(destType.getNonLValueExprType(S.Context)),
54 ValueKind(Expr::getValueKindForType(destType)),
55 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
57 if (const BuiltinType *placeholder =
58 src.get()->getType()->getAsPlaceholderType()) {
59 PlaceholderKind = placeholder->getKind();
61 PlaceholderKind = (BuiltinType::Kind) 0;
69 ExprValueKind ValueKind;
71 BuiltinType::Kind PlaceholderKind;
73 bool IsARCUnbridgedCast;
76 SourceRange DestRange;
78 // Top-level semantics-checking routines.
79 void CheckConstCast();
80 void CheckReinterpretCast();
81 void CheckStaticCast();
82 void CheckDynamicCast();
83 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
84 void CheckCStyleCast();
86 /// Complete an apparently-successful cast operation that yields
87 /// the given expression.
88 ExprResult complete(CastExpr *castExpr) {
89 // If this is an unbridged cast, wrap the result in an implicit
90 // cast that yields the unbridged-cast placeholder type.
91 if (IsARCUnbridgedCast) {
92 castExpr = ImplicitCastExpr::Create(Self.Context,
93 Self.Context.ARCUnbridgedCastTy,
94 CK_Dependent, castExpr, nullptr,
95 castExpr->getValueKind());
100 // Internal convenience methods.
102 /// Try to handle the given placeholder expression kind. Return
103 /// true if the source expression has the appropriate placeholder
104 /// kind. A placeholder can only be claimed once.
105 bool claimPlaceholder(BuiltinType::Kind K) {
106 if (PlaceholderKind != K) return false;
108 PlaceholderKind = (BuiltinType::Kind) 0;
112 bool isPlaceholder() const {
113 return PlaceholderKind != 0;
115 bool isPlaceholder(BuiltinType::Kind K) const {
116 return PlaceholderKind == K;
119 void checkCastAlign() {
120 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
123 void checkObjCConversion(Sema::CheckedConversionKind CCK) {
124 assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
126 Expr *src = SrcExpr.get();
127 if (Self.CheckObjCConversion(OpRange, DestType, src, CCK) ==
129 IsARCUnbridgedCast = true;
133 /// Check for and handle non-overload placeholder expressions.
134 void checkNonOverloadPlaceholders() {
135 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload))
138 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
139 if (SrcExpr.isInvalid())
141 PlaceholderKind = (BuiltinType::Kind) 0;
146 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
149 // The Try functions attempt a specific way of casting. If they succeed, they
150 // return TC_Success. If their way of casting is not appropriate for the given
151 // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
152 // to emit if no other way succeeds. If their way of casting is appropriate but
153 // fails, they return TC_Failed and *must* set diag; they can set it to 0 if
154 // they emit a specialized diagnostic.
155 // All diagnostics returned by these functions must expect the same three
157 // %0: Cast Type (a value from the CastType enumeration)
159 // %2: Destination Type
160 static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
161 QualType DestType, bool CStyle,
163 CXXCastPath &BasePath,
165 static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
166 QualType DestType, bool CStyle,
170 CXXCastPath &BasePath);
171 static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
172 QualType DestType, bool CStyle,
176 CXXCastPath &BasePath);
177 static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
178 CanQualType DestType, bool CStyle,
180 QualType OrigSrcType,
181 QualType OrigDestType, unsigned &msg,
183 CXXCastPath &BasePath);
184 static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
186 QualType DestType,bool CStyle,
190 CXXCastPath &BasePath);
192 static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
194 Sema::CheckedConversionKind CCK,
196 unsigned &msg, CastKind &Kind,
197 bool ListInitialization);
198 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
200 Sema::CheckedConversionKind CCK,
202 unsigned &msg, CastKind &Kind,
203 CXXCastPath &BasePath,
204 bool ListInitialization);
205 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
206 QualType DestType, bool CStyle,
208 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
209 QualType DestType, bool CStyle,
215 /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
217 Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
218 SourceLocation LAngleBracketLoc, Declarator &D,
219 SourceLocation RAngleBracketLoc,
220 SourceLocation LParenLoc, Expr *E,
221 SourceLocation RParenLoc) {
223 assert(!D.isInvalidType());
225 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType());
226 if (D.isInvalidType())
229 if (getLangOpts().CPlusPlus) {
230 // Check that there are no default arguments (C++ only).
231 CheckExtraCXXDefaultArguments(D);
234 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E,
235 SourceRange(LAngleBracketLoc, RAngleBracketLoc),
236 SourceRange(LParenLoc, RParenLoc));
240 Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
241 TypeSourceInfo *DestTInfo, Expr *E,
242 SourceRange AngleBrackets, SourceRange Parens) {
244 QualType DestType = DestTInfo->getType();
246 // If the type is dependent, we won't do the semantic analysis now.
248 DestType->isDependentType() || Ex.get()->isTypeDependent();
250 CastOperation Op(*this, DestType, E);
251 Op.OpRange = SourceRange(OpLoc, Parens.getEnd());
252 Op.DestRange = AngleBrackets;
255 default: llvm_unreachable("Unknown C++ cast!");
257 case tok::kw_const_cast:
258 if (!TypeDependent) {
260 if (Op.SrcExpr.isInvalid())
262 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
264 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType,
265 Op.ValueKind, Op.SrcExpr.get(), DestTInfo,
266 OpLoc, Parens.getEnd(),
269 case tok::kw_dynamic_cast: {
270 if (!TypeDependent) {
271 Op.CheckDynamicCast();
272 if (Op.SrcExpr.isInvalid())
275 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType,
276 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
277 &Op.BasePath, DestTInfo,
278 OpLoc, Parens.getEnd(),
281 case tok::kw_reinterpret_cast: {
282 if (!TypeDependent) {
283 Op.CheckReinterpretCast();
284 if (Op.SrcExpr.isInvalid())
286 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
288 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
289 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
290 nullptr, DestTInfo, OpLoc,
294 case tok::kw_static_cast: {
295 if (!TypeDependent) {
296 Op.CheckStaticCast();
297 if (Op.SrcExpr.isInvalid())
299 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
302 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType,
303 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
304 &Op.BasePath, DestTInfo,
305 OpLoc, Parens.getEnd(),
311 /// Try to diagnose a failed overloaded cast. Returns true if
312 /// diagnostics were emitted.
313 static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
314 SourceRange range, Expr *src,
316 bool listInitialization) {
318 // These cast kinds don't consider user-defined conversions.
331 QualType srcType = src->getType();
332 if (!destType->isRecordType() && !srcType->isRecordType())
335 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType);
336 InitializationKind initKind
337 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(),
338 range, listInitialization)
339 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range,
341 : InitializationKind::CreateCast(/*type range?*/ range);
342 InitializationSequence sequence(S, entity, initKind, src);
344 assert(sequence.Failed() && "initialization succeeded on second try?");
345 switch (sequence.getFailureKind()) {
346 default: return false;
348 case InitializationSequence::FK_ConstructorOverloadFailed:
349 case InitializationSequence::FK_UserConversionOverloadFailed:
353 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
356 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
358 switch (sequence.getFailedOverloadResult()) {
359 case OR_Success: llvm_unreachable("successful failed overload");
360 case OR_No_Viable_Function:
361 if (candidates.empty())
362 msg = diag::err_ovl_no_conversion_in_cast;
364 msg = diag::err_ovl_no_viable_conversion_in_cast;
365 howManyCandidates = OCD_AllCandidates;
369 msg = diag::err_ovl_ambiguous_conversion_in_cast;
370 howManyCandidates = OCD_ViableCandidates;
374 msg = diag::err_ovl_deleted_conversion_in_cast;
375 howManyCandidates = OCD_ViableCandidates;
379 S.Diag(range.getBegin(), msg)
380 << CT << srcType << destType
381 << range << src->getSourceRange();
383 candidates.NoteCandidates(S, howManyCandidates, src);
388 /// Diagnose a failed cast.
389 static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
390 SourceRange opRange, Expr *src, QualType destType,
391 bool listInitialization) {
392 if (msg == diag::err_bad_cxx_cast_generic &&
393 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType,
397 S.Diag(opRange.getBegin(), msg) << castType
398 << src->getType() << destType << opRange << src->getSourceRange();
400 // Detect if both types are (ptr to) class, and note any incompleteness.
401 int DifferentPtrness = 0;
402 QualType From = destType;
403 if (auto Ptr = From->getAs<PointerType>()) {
404 From = Ptr->getPointeeType();
407 QualType To = src->getType();
408 if (auto Ptr = To->getAs<PointerType>()) {
409 To = Ptr->getPointeeType();
412 if (!DifferentPtrness) {
413 auto RecFrom = From->getAs<RecordType>();
414 auto RecTo = To->getAs<RecordType>();
415 if (RecFrom && RecTo) {
416 auto DeclFrom = RecFrom->getAsCXXRecordDecl();
417 if (!DeclFrom->isCompleteDefinition())
418 S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete)
419 << DeclFrom->getDeclName();
420 auto DeclTo = RecTo->getAsCXXRecordDecl();
421 if (!DeclTo->isCompleteDefinition())
422 S.Diag(DeclTo->getLocation(), diag::note_type_incomplete)
423 << DeclTo->getDeclName();
428 /// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes,
429 /// this removes one level of indirection from both types, provided that they're
430 /// the same kind of pointer (plain or to-member). Unlike the Sema function,
431 /// this one doesn't care if the two pointers-to-member don't point into the
432 /// same class. This is because CastsAwayConstness doesn't care.
433 /// And additionally, it handles C++ references. If both the types are
434 /// references, then their pointee types are returned,
435 /// else if only one of them is reference, it's pointee type is returned,
436 /// and the other type is returned as-is.
437 static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) {
438 const PointerType *T1PtrType = T1->getAs<PointerType>(),
439 *T2PtrType = T2->getAs<PointerType>();
440 if (T1PtrType && T2PtrType) {
441 T1 = T1PtrType->getPointeeType();
442 T2 = T2PtrType->getPointeeType();
445 const ObjCObjectPointerType *T1ObjCPtrType =
446 T1->getAs<ObjCObjectPointerType>(),
448 T2->getAs<ObjCObjectPointerType>();
451 T1 = T1ObjCPtrType->getPointeeType();
452 T2 = T2ObjCPtrType->getPointeeType();
455 else if (T2PtrType) {
456 T1 = T1ObjCPtrType->getPointeeType();
457 T2 = T2PtrType->getPointeeType();
461 else if (T2ObjCPtrType) {
463 T2 = T2ObjCPtrType->getPointeeType();
464 T1 = T1PtrType->getPointeeType();
469 const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(),
470 *T2MPType = T2->getAs<MemberPointerType>();
471 if (T1MPType && T2MPType) {
472 T1 = T1MPType->getPointeeType();
473 T2 = T2MPType->getPointeeType();
477 const BlockPointerType *T1BPType = T1->getAs<BlockPointerType>(),
478 *T2BPType = T2->getAs<BlockPointerType>();
479 if (T1BPType && T2BPType) {
480 T1 = T1BPType->getPointeeType();
481 T2 = T2BPType->getPointeeType();
485 const LValueReferenceType *T1RefType = T1->getAs<LValueReferenceType>(),
486 *T2RefType = T2->getAs<LValueReferenceType>();
487 if (T1RefType && T2RefType) {
488 T1 = T1RefType->getPointeeType();
489 T2 = T2RefType->getPointeeType();
494 T1 = T1RefType->getPointeeType();
501 T2 = T2RefType->getPointeeType();
508 /// CastsAwayConstness - Check if the pointer conversion from SrcType to
509 /// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by
510 /// the cast checkers. Both arguments must denote pointer (possibly to member)
513 /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
515 /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
517 CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
518 bool CheckCVR, bool CheckObjCLifetime,
519 QualType *TheOffendingSrcType = nullptr,
520 QualType *TheOffendingDestType = nullptr,
521 Qualifiers *CastAwayQualifiers = nullptr) {
522 // If the only checking we care about is for Objective-C lifetime qualifiers,
523 // and we're not in ObjC mode, there's nothing to check.
524 if (!CheckCVR && CheckObjCLifetime &&
525 !Self.Context.getLangOpts().ObjC1)
528 // Casting away constness is defined in C++ 5.2.11p8 with reference to
529 // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since
530 // the rules are non-trivial. So first we construct Tcv *...cv* as described
532 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
533 SrcType->isBlockPointerType() ||
534 DestType->isLValueReferenceType()) &&
535 "Source type is not pointer or pointer to member.");
536 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
537 DestType->isBlockPointerType() ||
538 DestType->isLValueReferenceType()) &&
539 "Destination type is not pointer or pointer to member, or reference.");
541 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
542 UnwrappedDestType = Self.Context.getCanonicalType(DestType);
543 SmallVector<Qualifiers, 8> cv1, cv2;
545 // Find the qualifiers. We only care about cvr-qualifiers for the
546 // purpose of this check, because other qualifiers (address spaces,
547 // Objective-C GC, etc.) are part of the type's identity.
548 QualType PrevUnwrappedSrcType = UnwrappedSrcType;
549 QualType PrevUnwrappedDestType = UnwrappedDestType;
550 while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
551 // Determine the relevant qualifiers at this level.
552 Qualifiers SrcQuals, DestQuals;
553 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals);
554 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals);
556 Qualifiers RetainedSrcQuals, RetainedDestQuals;
558 RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers());
559 RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers());
561 if (RetainedSrcQuals != RetainedDestQuals && TheOffendingSrcType &&
562 TheOffendingDestType && CastAwayQualifiers) {
563 *TheOffendingSrcType = PrevUnwrappedSrcType;
564 *TheOffendingDestType = PrevUnwrappedDestType;
565 *CastAwayQualifiers = RetainedSrcQuals - RetainedDestQuals;
569 if (CheckObjCLifetime &&
570 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals))
573 cv1.push_back(RetainedSrcQuals);
574 cv2.push_back(RetainedDestQuals);
576 PrevUnwrappedSrcType = UnwrappedSrcType;
577 PrevUnwrappedDestType = UnwrappedDestType;
582 // Construct void pointers with those qualifiers (in reverse order of
583 // unwrapping, of course).
584 QualType SrcConstruct = Self.Context.VoidTy;
585 QualType DestConstruct = Self.Context.VoidTy;
586 ASTContext &Context = Self.Context;
587 for (SmallVectorImpl<Qualifiers>::reverse_iterator i1 = cv1.rbegin(),
589 i1 != cv1.rend(); ++i1, ++i2) {
591 = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1));
593 = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2));
596 // Test if they're compatible.
597 bool ObjCLifetimeConversion;
598 return SrcConstruct != DestConstruct &&
599 !Self.IsQualificationConversion(SrcConstruct, DestConstruct, false,
600 ObjCLifetimeConversion);
603 /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
604 /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
605 /// checked downcasts in class hierarchies.
606 void CastOperation::CheckDynamicCast() {
607 if (ValueKind == VK_RValue)
608 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
609 else if (isPlaceholder())
610 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
611 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
614 QualType OrigSrcType = SrcExpr.get()->getType();
615 QualType DestType = Self.Context.getCanonicalType(this->DestType);
617 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
618 // or "pointer to cv void".
620 QualType DestPointee;
621 const PointerType *DestPointer = DestType->getAs<PointerType>();
622 const ReferenceType *DestReference = nullptr;
624 DestPointee = DestPointer->getPointeeType();
625 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
626 DestPointee = DestReference->getPointeeType();
628 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
629 << this->DestType << DestRange;
630 SrcExpr = ExprError();
634 const RecordType *DestRecord = DestPointee->getAs<RecordType>();
635 if (DestPointee->isVoidType()) {
636 assert(DestPointer && "Reference to void is not possible");
637 } else if (DestRecord) {
638 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee,
639 diag::err_bad_dynamic_cast_incomplete,
641 SrcExpr = ExprError();
645 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
646 << DestPointee.getUnqualifiedType() << DestRange;
647 SrcExpr = ExprError();
651 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
652 // complete class type, [...]. If T is an lvalue reference type, v shall be
653 // an lvalue of a complete class type, [...]. If T is an rvalue reference
654 // type, v shall be an expression having a complete class type, [...]
655 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
658 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
659 SrcPointee = SrcPointer->getPointeeType();
661 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
662 << OrigSrcType << SrcExpr.get()->getSourceRange();
663 SrcExpr = ExprError();
666 } else if (DestReference->isLValueReferenceType()) {
667 if (!SrcExpr.get()->isLValue()) {
668 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
669 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
671 SrcPointee = SrcType;
673 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
674 // to materialize the prvalue before we bind the reference to it.
675 if (SrcExpr.get()->isRValue())
676 SrcExpr = Self.CreateMaterializeTemporaryExpr(
677 SrcType, SrcExpr.get(), /*IsLValueReference*/ false);
678 SrcPointee = SrcType;
681 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
683 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
684 diag::err_bad_dynamic_cast_incomplete,
686 SrcExpr = ExprError();
690 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
691 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
692 SrcExpr = ExprError();
696 assert((DestPointer || DestReference) &&
697 "Bad destination non-ptr/ref slipped through.");
698 assert((DestRecord || DestPointee->isVoidType()) &&
699 "Bad destination pointee slipped through.");
700 assert(SrcRecord && "Bad source pointee slipped through.");
702 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
703 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
704 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away)
705 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
706 SrcExpr = ExprError();
710 // C++ 5.2.7p3: If the type of v is the same as the required result type,
712 if (DestRecord == SrcRecord) {
718 // Upcasts are resolved statically.
720 Self.IsDerivedFrom(OpRange.getBegin(), SrcPointee, DestPointee)) {
721 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
722 OpRange.getBegin(), OpRange,
724 SrcExpr = ExprError();
728 Kind = CK_DerivedToBase;
732 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
733 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
734 assert(SrcDecl && "Definition missing");
735 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
736 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
737 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
738 SrcExpr = ExprError();
741 // dynamic_cast is not available with -fno-rtti.
742 // As an exception, dynamic_cast to void* is available because it doesn't
744 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
745 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti);
746 SrcExpr = ExprError();
750 // Done. Everything else is run-time checks.
754 /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
755 /// Refer to C++ 5.2.11 for details. const_cast is typically used in code
757 /// const char *str = "literal";
758 /// legacy_function(const_cast\<char*\>(str));
759 void CastOperation::CheckConstCast() {
760 if (ValueKind == VK_RValue)
761 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
762 else if (isPlaceholder())
763 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
764 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
767 unsigned msg = diag::err_bad_cxx_cast_generic;
768 if (TryConstCast(Self, SrcExpr, DestType, /*CStyle*/false, msg) != TC_Success
770 Self.Diag(OpRange.getBegin(), msg) << CT_Const
771 << SrcExpr.get()->getType() << DestType << OpRange;
772 SrcExpr = ExprError();
776 /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
777 /// or downcast between respective pointers or references.
778 static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
780 SourceRange OpRange) {
781 QualType SrcType = SrcExpr->getType();
782 // When casting from pointer or reference, get pointee type; use original
784 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
785 const CXXRecordDecl *SrcRD =
786 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
788 // Examining subobjects for records is only possible if the complete and
789 // valid definition is available. Also, template instantiation is not
791 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
794 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
796 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
804 CXXBasePaths BasePaths;
806 if (SrcRD->isDerivedFrom(DestRD, BasePaths))
807 ReinterpretKind = ReinterpretUpcast;
808 else if (DestRD->isDerivedFrom(SrcRD, BasePaths))
809 ReinterpretKind = ReinterpretDowncast;
813 bool VirtualBase = true;
814 bool NonZeroOffset = false;
815 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
818 const CXXBasePath &Path = *I;
819 CharUnits Offset = CharUnits::Zero();
820 bool IsVirtual = false;
821 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
822 IElem != EElem; ++IElem) {
823 IsVirtual = IElem->Base->isVirtual();
826 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
827 assert(BaseRD && "Base type should be a valid unqualified class type");
828 // Don't check if any base has invalid declaration or has no definition
829 // since it has no layout info.
830 const CXXRecordDecl *Class = IElem->Class,
831 *ClassDefinition = Class->getDefinition();
832 if (Class->isInvalidDecl() || !ClassDefinition ||
833 !ClassDefinition->isCompleteDefinition())
836 const ASTRecordLayout &DerivedLayout =
837 Self.Context.getASTRecordLayout(Class);
838 Offset += DerivedLayout.getBaseClassOffset(BaseRD);
841 // Don't warn if any path is a non-virtually derived base at offset zero.
844 // Offset makes sense only for non-virtual bases.
846 NonZeroOffset = true;
848 VirtualBase = VirtualBase && IsVirtual;
851 (void) NonZeroOffset; // Silence set but not used warning.
852 assert((VirtualBase || NonZeroOffset) &&
853 "Should have returned if has non-virtual base with zero offset");
856 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
857 QualType DerivedType =
858 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
860 SourceLocation BeginLoc = OpRange.getBegin();
861 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static)
862 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
864 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static)
865 << int(ReinterpretKind)
866 << FixItHint::CreateReplacement(BeginLoc, "static_cast");
869 /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
871 /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
873 /// char *bytes = reinterpret_cast\<char*\>(int_ptr);
874 void CastOperation::CheckReinterpretCast() {
875 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload))
876 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
878 checkNonOverloadPlaceholders();
879 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
882 unsigned msg = diag::err_bad_cxx_cast_generic;
884 TryReinterpretCast(Self, SrcExpr, DestType,
885 /*CStyle*/false, OpRange, msg, Kind);
886 if (tcr != TC_Success && msg != 0)
888 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
890 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
891 //FIXME: &f<int>; is overloaded and resolvable
892 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload)
893 << OverloadExpr::find(SrcExpr.get()).Expression->getName()
894 << DestType << OpRange;
895 Self.NoteAllOverloadCandidates(SrcExpr.get());
898 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(),
899 DestType, /*listInitialization=*/false);
901 SrcExpr = ExprError();
902 } else if (tcr == TC_Success) {
903 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
904 checkObjCConversion(Sema::CCK_OtherCast);
905 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
910 /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
911 /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
912 /// implicit conversions explicit and getting rid of data loss warnings.
913 void CastOperation::CheckStaticCast() {
914 if (isPlaceholder()) {
915 checkNonOverloadPlaceholders();
916 if (SrcExpr.isInvalid())
920 // This test is outside everything else because it's the only case where
921 // a non-lvalue-reference target type does not lead to decay.
922 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
923 if (DestType->isVoidType()) {
926 if (claimPlaceholder(BuiltinType::Overload)) {
927 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
928 false, // Decay Function to ptr
930 OpRange, DestType, diag::err_bad_static_cast_overload);
931 if (SrcExpr.isInvalid())
935 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
939 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
940 !isPlaceholder(BuiltinType::Overload)) {
941 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
942 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
946 unsigned msg = diag::err_bad_cxx_cast_generic;
948 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg,
949 Kind, BasePath, /*ListInitialization=*/false);
950 if (tcr != TC_Success && msg != 0) {
951 if (SrcExpr.isInvalid())
953 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
954 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression;
955 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload)
956 << oe->getName() << DestType << OpRange
957 << oe->getQualifierLoc().getSourceRange();
958 Self.NoteAllOverloadCandidates(SrcExpr.get());
960 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType,
961 /*listInitialization=*/false);
963 SrcExpr = ExprError();
964 } else if (tcr == TC_Success) {
965 if (Kind == CK_BitCast)
967 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
968 checkObjCConversion(Sema::CCK_OtherCast);
969 } else if (Kind == CK_BitCast) {
974 /// TryStaticCast - Check if a static cast can be performed, and do so if
975 /// possible. If @p CStyle, ignore access restrictions on hierarchy casting
976 /// and casting away constness.
977 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
979 Sema::CheckedConversionKind CCK,
980 SourceRange OpRange, unsigned &msg,
981 CastKind &Kind, CXXCastPath &BasePath,
982 bool ListInitialization) {
983 // Determine whether we have the semantics of a C-style cast.
985 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
987 // The order the tests is not entirely arbitrary. There is one conversion
988 // that can be handled in two different ways. Given:
990 // struct B : public A {
994 // the cast static_cast<const B&>(a) could be seen as either a static
995 // reference downcast, or an explicit invocation of the user-defined
996 // conversion using B's conversion constructor.
997 // DR 427 specifies that the downcast is to be applied here.
999 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1000 // Done outside this function.
1004 // C++ 5.2.9p5, reference downcast.
1005 // See the function for details.
1006 // DR 427 specifies that this is to be applied before paragraph 2.
1007 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle,
1008 OpRange, msg, Kind, BasePath);
1009 if (tcr != TC_NotApplicable)
1012 // C++11 [expr.static.cast]p3:
1013 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
1014 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1015 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind,
1017 if (tcr != TC_NotApplicable)
1020 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
1021 // [...] if the declaration "T t(e);" is well-formed, [...].
1022 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
1023 Kind, ListInitialization);
1024 if (SrcExpr.isInvalid())
1026 if (tcr != TC_NotApplicable)
1029 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
1030 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
1031 // conversions, subject to further restrictions.
1032 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
1033 // of qualification conversions impossible.
1034 // In the CStyle case, the earlier attempt to const_cast should have taken
1035 // care of reverse qualification conversions.
1037 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType());
1039 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
1040 // converted to an integral type. [...] A value of a scoped enumeration type
1041 // can also be explicitly converted to a floating-point type [...].
1042 if (const EnumType *Enum = SrcType->getAs<EnumType>()) {
1043 if (Enum->getDecl()->isScoped()) {
1044 if (DestType->isBooleanType()) {
1045 Kind = CK_IntegralToBoolean;
1047 } else if (DestType->isIntegralType(Self.Context)) {
1048 Kind = CK_IntegralCast;
1050 } else if (DestType->isRealFloatingType()) {
1051 Kind = CK_IntegralToFloating;
1057 // Reverse integral promotion/conversion. All such conversions are themselves
1058 // again integral promotions or conversions and are thus already handled by
1059 // p2 (TryDirectInitialization above).
1060 // (Note: any data loss warnings should be suppressed.)
1061 // The exception is the reverse of enum->integer, i.e. integer->enum (and
1062 // enum->enum). See also C++ 5.2.9p7.
1063 // The same goes for reverse floating point promotion/conversion and
1064 // floating-integral conversions. Again, only floating->enum is relevant.
1065 if (DestType->isEnumeralType()) {
1066 if (SrcType->isIntegralOrEnumerationType()) {
1067 Kind = CK_IntegralCast;
1069 } else if (SrcType->isRealFloatingType()) {
1070 Kind = CK_FloatingToIntegral;
1075 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1076 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1077 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1079 if (tcr != TC_NotApplicable)
1082 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1083 // conversion. C++ 5.2.9p9 has additional information.
1084 // DR54's access restrictions apply here also.
1085 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1086 OpRange, msg, Kind, BasePath);
1087 if (tcr != TC_NotApplicable)
1090 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1091 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1092 // just the usual constness stuff.
1093 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1094 QualType SrcPointee = SrcPointer->getPointeeType();
1095 if (SrcPointee->isVoidType()) {
1096 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1097 QualType DestPointee = DestPointer->getPointeeType();
1098 if (DestPointee->isIncompleteOrObjectType()) {
1099 // This is definitely the intended conversion, but it might fail due
1100 // to a qualifier violation. Note that we permit Objective-C lifetime
1101 // and GC qualifier mismatches here.
1103 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1104 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1105 DestPointeeQuals.removeObjCGCAttr();
1106 DestPointeeQuals.removeObjCLifetime();
1107 SrcPointeeQuals.removeObjCGCAttr();
1108 SrcPointeeQuals.removeObjCLifetime();
1109 if (DestPointeeQuals != SrcPointeeQuals &&
1110 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) {
1111 msg = diag::err_bad_cxx_cast_qualifiers_away;
1119 // Microsoft permits static_cast from 'pointer-to-void' to
1120 // 'pointer-to-function'.
1121 if (!CStyle && Self.getLangOpts().MSVCCompat &&
1122 DestPointee->isFunctionType()) {
1123 Self.Diag(OpRange.getBegin(), diag::ext_ms_cast_fn_obj) << OpRange;
1128 else if (DestType->isObjCObjectPointerType()) {
1129 // allow both c-style cast and static_cast of objective-c pointers as
1130 // they are pervasive.
1131 Kind = CK_CPointerToObjCPointerCast;
1134 else if (CStyle && DestType->isBlockPointerType()) {
1135 // allow c-style cast of void * to block pointers.
1136 Kind = CK_AnyPointerToBlockPointerCast;
1141 // Allow arbitray objective-c pointer conversion with static casts.
1142 if (SrcType->isObjCObjectPointerType() &&
1143 DestType->isObjCObjectPointerType()) {
1147 // Allow ns-pointer to cf-pointer conversion in either direction
1148 // with static casts.
1150 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
1153 // See if it looks like the user is trying to convert between
1154 // related record types, and select a better diagnostic if so.
1155 if (auto SrcPointer = SrcType->getAs<PointerType>())
1156 if (auto DestPointer = DestType->getAs<PointerType>())
1157 if (SrcPointer->getPointeeType()->getAs<RecordType>() &&
1158 DestPointer->getPointeeType()->getAs<RecordType>())
1159 msg = diag::err_bad_cxx_cast_unrelated_class;
1161 // We tried everything. Everything! Nothing works! :-(
1162 return TC_NotApplicable;
1165 /// Tests whether a conversion according to N2844 is valid.
1166 TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
1167 QualType DestType, bool CStyle,
1168 CastKind &Kind, CXXCastPath &BasePath,
1170 // C++11 [expr.static.cast]p3:
1171 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1172 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1173 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1175 return TC_NotApplicable;
1177 if (!SrcExpr->isGLValue())
1178 return TC_NotApplicable;
1180 // Because we try the reference downcast before this function, from now on
1181 // this is the only cast possibility, so we issue an error if we fail now.
1182 // FIXME: Should allow casting away constness if CStyle.
1184 bool ObjCConversion;
1185 bool ObjCLifetimeConversion;
1186 QualType FromType = SrcExpr->getType();
1187 QualType ToType = R->getPointeeType();
1189 FromType = FromType.getUnqualifiedType();
1190 ToType = ToType.getUnqualifiedType();
1193 Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship(
1194 SrcExpr->getLocStart(), ToType, FromType, DerivedToBase, ObjCConversion,
1195 ObjCLifetimeConversion);
1196 if (RefResult != Sema::Ref_Compatible) {
1197 if (CStyle || RefResult == Sema::Ref_Incompatible)
1198 return TC_NotApplicable;
1199 // Diagnose types which are reference-related but not compatible here since
1200 // we can provide better diagnostics. In these cases forwarding to
1201 // [expr.static.cast]p4 should never result in a well-formed cast.
1202 msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast
1203 : diag::err_bad_rvalue_to_rvalue_cast;
1207 if (DerivedToBase) {
1208 Kind = CK_DerivedToBase;
1209 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1210 /*DetectVirtual=*/true);
1211 if (!Self.IsDerivedFrom(SrcExpr->getLocStart(), SrcExpr->getType(),
1212 R->getPointeeType(), Paths))
1213 return TC_NotApplicable;
1215 Self.BuildBasePathArray(Paths, BasePath);
1222 /// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1224 TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
1225 bool CStyle, SourceRange OpRange,
1226 unsigned &msg, CastKind &Kind,
1227 CXXCastPath &BasePath) {
1228 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1229 // cast to type "reference to cv2 D", where D is a class derived from B,
1230 // if a valid standard conversion from "pointer to D" to "pointer to B"
1231 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1232 // In addition, DR54 clarifies that the base must be accessible in the
1233 // current context. Although the wording of DR54 only applies to the pointer
1234 // variant of this rule, the intent is clearly for it to apply to the this
1235 // conversion as well.
1237 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1238 if (!DestReference) {
1239 return TC_NotApplicable;
1241 bool RValueRef = DestReference->isRValueReferenceType();
1242 if (!RValueRef && !SrcExpr->isLValue()) {
1243 // We know the left side is an lvalue reference, so we can suggest a reason.
1244 msg = diag::err_bad_cxx_cast_rvalue;
1245 return TC_NotApplicable;
1248 QualType DestPointee = DestReference->getPointeeType();
1250 // FIXME: If the source is a prvalue, we should issue a warning (because the
1251 // cast always has undefined behavior), and for AST consistency, we should
1252 // materialize a temporary.
1253 return TryStaticDowncast(Self,
1254 Self.Context.getCanonicalType(SrcExpr->getType()),
1255 Self.Context.getCanonicalType(DestPointee), CStyle,
1256 OpRange, SrcExpr->getType(), DestType, msg, Kind,
1260 /// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1262 TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
1263 bool CStyle, SourceRange OpRange,
1264 unsigned &msg, CastKind &Kind,
1265 CXXCastPath &BasePath) {
1266 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1267 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1268 // is a class derived from B, if a valid standard conversion from "pointer
1269 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1271 // In addition, DR54 clarifies that the base must be accessible in the
1274 const PointerType *DestPointer = DestType->getAs<PointerType>();
1276 return TC_NotApplicable;
1279 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1281 msg = diag::err_bad_static_cast_pointer_nonpointer;
1282 return TC_NotApplicable;
1285 return TryStaticDowncast(Self,
1286 Self.Context.getCanonicalType(SrcPointer->getPointeeType()),
1287 Self.Context.getCanonicalType(DestPointer->getPointeeType()),
1288 CStyle, OpRange, SrcType, DestType, msg, Kind,
1292 /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1293 /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1294 /// DestType is possible and allowed.
1296 TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType,
1297 bool CStyle, SourceRange OpRange, QualType OrigSrcType,
1298 QualType OrigDestType, unsigned &msg,
1299 CastKind &Kind, CXXCastPath &BasePath) {
1300 // We can only work with complete types. But don't complain if it doesn't work
1301 if (!Self.isCompleteType(OpRange.getBegin(), SrcType) ||
1302 !Self.isCompleteType(OpRange.getBegin(), DestType))
1303 return TC_NotApplicable;
1305 // Downcast can only happen in class hierarchies, so we need classes.
1306 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1307 return TC_NotApplicable;
1310 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1311 /*DetectVirtual=*/true);
1312 if (!Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths)) {
1313 return TC_NotApplicable;
1316 // Target type does derive from source type. Now we're serious. If an error
1317 // appears now, it's not ignored.
1318 // This may not be entirely in line with the standard. Take for example:
1320 // struct B : virtual A {
1326 // (void)static_cast<const B&>(*((A*)0));
1328 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1329 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1330 // However, both GCC and Comeau reject this example, and accepting it would
1331 // mean more complex code if we're to preserve the nice error message.
1332 // FIXME: Being 100% compliant here would be nice to have.
1334 // Must preserve cv, as always, unless we're in C-style mode.
1335 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) {
1336 msg = diag::err_bad_cxx_cast_qualifiers_away;
1340 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
1341 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1342 // that it builds the paths in reverse order.
1343 // To sum up: record all paths to the base and build a nice string from
1344 // them. Use it to spice up the error message.
1345 if (!Paths.isRecordingPaths()) {
1347 Paths.setRecordingPaths(true);
1348 Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths);
1350 std::string PathDisplayStr;
1351 std::set<unsigned> DisplayedPaths;
1352 for (clang::CXXBasePath &Path : Paths) {
1353 if (DisplayedPaths.insert(Path.back().SubobjectNumber).second) {
1354 // We haven't displayed a path to this particular base
1355 // class subobject yet.
1356 PathDisplayStr += "\n ";
1357 for (CXXBasePathElement &PE : llvm::reverse(Path))
1358 PathDisplayStr += PE.Base->getType().getAsString() + " -> ";
1359 PathDisplayStr += QualType(DestType).getAsString();
1363 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
1364 << QualType(SrcType).getUnqualifiedType()
1365 << QualType(DestType).getUnqualifiedType()
1366 << PathDisplayStr << OpRange;
1371 if (Paths.getDetectedVirtual() != nullptr) {
1372 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1373 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
1374 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1380 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1383 diag::err_downcast_from_inaccessible_base)) {
1384 case Sema::AR_accessible:
1385 case Sema::AR_delayed: // be optimistic
1386 case Sema::AR_dependent: // be optimistic
1389 case Sema::AR_inaccessible:
1395 Self.BuildBasePathArray(Paths, BasePath);
1396 Kind = CK_BaseToDerived;
1400 /// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1401 /// C++ 5.2.9p9 is valid:
1403 /// An rvalue of type "pointer to member of D of type cv1 T" can be
1404 /// converted to an rvalue of type "pointer to member of B of type cv2 T",
1405 /// where B is a base class of D [...].
1408 TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
1409 QualType DestType, bool CStyle,
1410 SourceRange OpRange,
1411 unsigned &msg, CastKind &Kind,
1412 CXXCastPath &BasePath) {
1413 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1415 return TC_NotApplicable;
1417 bool WasOverloadedFunction = false;
1418 DeclAccessPair FoundOverload;
1419 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1420 if (FunctionDecl *Fn
1421 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false,
1423 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
1424 SrcType = Self.Context.getMemberPointerType(Fn->getType(),
1425 Self.Context.getTypeDeclType(M->getParent()).getTypePtr());
1426 WasOverloadedFunction = true;
1430 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1432 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1433 return TC_NotApplicable;
1436 // Lock down the inheritance model right now in MS ABI, whether or not the
1437 // pointee types are the same.
1438 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1439 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
1440 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
1443 // T == T, modulo cv
1444 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(),
1445 DestMemPtr->getPointeeType()))
1446 return TC_NotApplicable;
1449 QualType SrcClass(SrcMemPtr->getClass(), 0);
1450 QualType DestClass(DestMemPtr->getClass(), 0);
1451 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1452 /*DetectVirtual=*/true);
1453 if (!Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths))
1454 return TC_NotApplicable;
1456 // B is a base of D. But is it an allowed base? If not, it's a hard error.
1457 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) {
1459 Paths.setRecordingPaths(true);
1461 Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths);
1464 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths);
1465 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv)
1466 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange;
1471 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
1472 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
1473 << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
1479 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1480 DestClass, SrcClass,
1482 diag::err_upcast_to_inaccessible_base)) {
1483 case Sema::AR_accessible:
1484 case Sema::AR_delayed:
1485 case Sema::AR_dependent:
1486 // Optimistically assume that the delayed and dependent cases
1490 case Sema::AR_inaccessible:
1496 if (WasOverloadedFunction) {
1497 // Resolve the address of the overloaded function again, this time
1498 // allowing complaints if something goes wrong.
1499 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
1508 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn);
1509 if (!SrcExpr.isUsable()) {
1515 Self.BuildBasePathArray(Paths, BasePath);
1516 Kind = CK_DerivedToBaseMemberPointer;
1520 /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1523 /// An expression e can be explicitly converted to a type T using a
1524 /// @c static_cast if the declaration "T t(e);" is well-formed [...].
1526 TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType,
1527 Sema::CheckedConversionKind CCK,
1528 SourceRange OpRange, unsigned &msg,
1529 CastKind &Kind, bool ListInitialization) {
1530 if (DestType->isRecordType()) {
1531 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1532 diag::err_bad_dynamic_cast_incomplete) ||
1533 Self.RequireNonAbstractType(OpRange.getBegin(), DestType,
1534 diag::err_allocation_of_abstract_type)) {
1540 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType);
1541 InitializationKind InitKind
1542 = (CCK == Sema::CCK_CStyleCast)
1543 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange,
1545 : (CCK == Sema::CCK_FunctionalCast)
1546 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization)
1547 : InitializationKind::CreateCast(OpRange);
1548 Expr *SrcExprRaw = SrcExpr.get();
1549 // FIXME: Per DR242, we should check for an implicit conversion sequence
1550 // or for a constructor that could be invoked by direct-initialization
1551 // here, not for an initialization sequence.
1552 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1554 // At this point of CheckStaticCast, if the destination is a reference,
1555 // or the expression is an overload expression this has to work.
1556 // There is no other way that works.
1557 // On the other hand, if we're checking a C-style cast, we've still got
1558 // the reinterpret_cast way.
1560 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1561 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1562 return TC_NotApplicable;
1564 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw);
1565 if (Result.isInvalid()) {
1570 if (InitSeq.isConstructorInitialization())
1571 Kind = CK_ConstructorConversion;
1579 /// TryConstCast - See if a const_cast from source to destination is allowed,
1580 /// and perform it if it is.
1581 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1582 QualType DestType, bool CStyle,
1584 DestType = Self.Context.getCanonicalType(DestType);
1585 QualType SrcType = SrcExpr.get()->getType();
1586 bool NeedToMaterializeTemporary = false;
1588 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1590 // if a pointer to T1 can be explicitly converted to the type "pointer to
1591 // T2" using a const_cast, then the following conversions can also be
1593 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1594 // type T2 using the cast const_cast<T2&>;
1595 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1596 // type T2 using the cast const_cast<T2&&>; and
1597 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1598 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1600 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1601 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1602 // is C-style, static_cast might find a way, so we simply suggest a
1603 // message and tell the parent to keep searching.
1604 msg = diag::err_bad_cxx_cast_rvalue;
1605 return TC_NotApplicable;
1608 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) {
1609 if (!SrcType->isRecordType()) {
1610 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1611 // this is C-style, static_cast can do this.
1612 msg = diag::err_bad_cxx_cast_rvalue;
1613 return TC_NotApplicable;
1616 // Materialize the class prvalue so that the const_cast can bind a
1618 NeedToMaterializeTemporary = true;
1621 // It's not completely clear under the standard whether we can
1622 // const_cast bit-field gl-values. Doing so would not be
1623 // intrinsically complicated, but for now, we say no for
1624 // consistency with other compilers and await the word of the
1626 if (SrcExpr.get()->refersToBitField()) {
1627 msg = diag::err_bad_cxx_cast_bitfield;
1628 return TC_NotApplicable;
1631 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1632 SrcType = Self.Context.getPointerType(SrcType);
1635 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
1636 // the rules for const_cast are the same as those used for pointers.
1638 if (!DestType->isPointerType() &&
1639 !DestType->isMemberPointerType() &&
1640 !DestType->isObjCObjectPointerType()) {
1641 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
1642 // was a reference type, we converted it to a pointer above.
1643 // The status of rvalue references isn't entirely clear, but it looks like
1644 // conversion to them is simply invalid.
1645 // C++ 5.2.11p3: For two pointer types [...]
1647 msg = diag::err_bad_const_cast_dest;
1648 return TC_NotApplicable;
1650 if (DestType->isFunctionPointerType() ||
1651 DestType->isMemberFunctionPointerType()) {
1652 // Cannot cast direct function pointers.
1653 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
1654 // T is the ultimate pointee of source and target type.
1656 msg = diag::err_bad_const_cast_dest;
1657 return TC_NotApplicable;
1659 SrcType = Self.Context.getCanonicalType(SrcType);
1661 // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are
1662 // completely equal.
1663 // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers
1664 // in multi-level pointers may change, but the level count must be the same,
1665 // as must be the final pointee type.
1666 while (SrcType != DestType &&
1667 Self.Context.UnwrapSimilarPointerTypes(SrcType, DestType)) {
1668 Qualifiers SrcQuals, DestQuals;
1669 SrcType = Self.Context.getUnqualifiedArrayType(SrcType, SrcQuals);
1670 DestType = Self.Context.getUnqualifiedArrayType(DestType, DestQuals);
1672 // const_cast is permitted to strip cvr-qualifiers, only. Make sure that
1673 // the other qualifiers (e.g., address spaces) are identical.
1674 SrcQuals.removeCVRQualifiers();
1675 DestQuals.removeCVRQualifiers();
1676 if (SrcQuals != DestQuals)
1677 return TC_NotApplicable;
1680 // Since we're dealing in canonical types, the remainder must be the same.
1681 if (SrcType != DestType)
1682 return TC_NotApplicable;
1684 if (NeedToMaterializeTemporary)
1685 // This is a const_cast from a class prvalue to an rvalue reference type.
1686 // Materialize a temporary to store the result of the conversion.
1687 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcExpr.get()->getType(),
1689 /*IsLValueReference*/ false);
1694 // Checks for undefined behavior in reinterpret_cast.
1695 // The cases that is checked for is:
1696 // *reinterpret_cast<T*>(&a)
1697 // reinterpret_cast<T&>(a)
1698 // where accessing 'a' as type 'T' will result in undefined behavior.
1699 void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
1701 SourceRange Range) {
1702 unsigned DiagID = IsDereference ?
1703 diag::warn_pointer_indirection_from_incompatible_type :
1704 diag::warn_undefined_reinterpret_cast;
1706 if (Diags.isIgnored(DiagID, Range.getBegin()))
1709 QualType SrcTy, DestTy;
1710 if (IsDereference) {
1711 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
1714 SrcTy = SrcType->getPointeeType();
1715 DestTy = DestType->getPointeeType();
1717 if (!DestType->getAs<ReferenceType>()) {
1721 DestTy = DestType->getPointeeType();
1724 // Cast is compatible if the types are the same.
1725 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) {
1728 // or one of the types is a char or void type
1729 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
1730 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
1733 // or one of the types is a tag type.
1734 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
1738 // FIXME: Scoped enums?
1739 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
1740 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
1741 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) {
1746 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range;
1749 static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
1750 QualType DestType) {
1751 QualType SrcType = SrcExpr.get()->getType();
1752 if (Self.Context.hasSameType(SrcType, DestType))
1754 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
1755 if (SrcPtrTy->isObjCSelType()) {
1756 QualType DT = DestType;
1757 if (isa<PointerType>(DestType))
1758 DT = DestType->getPointeeType();
1759 if (!DT.getUnqualifiedType()->isVoidType())
1760 Self.Diag(SrcExpr.get()->getExprLoc(),
1761 diag::warn_cast_pointer_from_sel)
1762 << SrcType << DestType << SrcExpr.get()->getSourceRange();
1766 /// Diagnose casts that change the calling convention of a pointer to a function
1767 /// defined in the current TU.
1768 static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr,
1769 QualType DstType, SourceRange OpRange) {
1770 // Check if this cast would change the calling convention of a function
1772 QualType SrcType = SrcExpr.get()->getType();
1773 if (Self.Context.hasSameType(SrcType, DstType) ||
1774 !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType())
1776 const auto *SrcFTy =
1777 SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1778 const auto *DstFTy =
1779 DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1780 CallingConv SrcCC = SrcFTy->getCallConv();
1781 CallingConv DstCC = DstFTy->getCallConv();
1785 // We have a calling convention cast. Check if the source is a pointer to a
1786 // known, specific function that has already been defined.
1787 Expr *Src = SrcExpr.get()->IgnoreParenImpCasts();
1788 if (auto *UO = dyn_cast<UnaryOperator>(Src))
1789 if (UO->getOpcode() == UO_AddrOf)
1790 Src = UO->getSubExpr()->IgnoreParenImpCasts();
1791 auto *DRE = dyn_cast<DeclRefExpr>(Src);
1794 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
1798 // Only warn if we are casting from the default convention to a non-default
1799 // convention. This can happen when the programmer forgot to apply the calling
1800 // convention to the function declaration and then inserted this cast to
1801 // satisfy the type system.
1802 CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
1803 FD->isVariadic(), FD->isCXXInstanceMember());
1804 if (DstCC == DefaultCC || SrcCC != DefaultCC)
1807 // Diagnose this cast, as it is probably bad.
1808 StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC);
1809 StringRef DstCCName = FunctionType::getNameForCallConv(DstCC);
1810 Self.Diag(OpRange.getBegin(), diag::warn_cast_calling_conv)
1811 << SrcCCName << DstCCName << OpRange;
1813 // The checks above are cheaper than checking if the diagnostic is enabled.
1814 // However, it's worth checking if the warning is enabled before we construct
1816 if (Self.Diags.isIgnored(diag::warn_cast_calling_conv, OpRange.getBegin()))
1819 // Try to suggest a fixit to change the calling convention of the function
1820 // whose address was taken. Try to use the latest macro for the convention.
1821 // For example, users probably want to write "WINAPI" instead of "__stdcall"
1822 // to match the Windows header declarations.
1823 SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc();
1824 Preprocessor &PP = Self.getPreprocessor();
1825 SmallVector<TokenValue, 6> AttrTokens;
1826 SmallString<64> CCAttrText;
1827 llvm::raw_svector_ostream OS(CCAttrText);
1828 if (Self.getLangOpts().MicrosoftExt) {
1829 // __stdcall or __vectorcall
1830 OS << "__" << DstCCName;
1831 IdentifierInfo *II = PP.getIdentifierInfo(OS.str());
1832 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1833 ? TokenValue(II->getTokenID())
1836 // __attribute__((stdcall)) or __attribute__((vectorcall))
1837 OS << "__attribute__((" << DstCCName << "))";
1838 AttrTokens.push_back(tok::kw___attribute);
1839 AttrTokens.push_back(tok::l_paren);
1840 AttrTokens.push_back(tok::l_paren);
1841 IdentifierInfo *II = PP.getIdentifierInfo(DstCCName);
1842 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1843 ? TokenValue(II->getTokenID())
1845 AttrTokens.push_back(tok::r_paren);
1846 AttrTokens.push_back(tok::r_paren);
1848 StringRef AttrSpelling = PP.getLastMacroWithSpelling(NameLoc, AttrTokens);
1849 if (!AttrSpelling.empty())
1850 CCAttrText = AttrSpelling;
1852 Self.Diag(NameLoc, diag::note_change_calling_conv_fixit)
1853 << FD << DstCCName << FixItHint::CreateInsertion(NameLoc, CCAttrText);
1856 static void checkIntToPointerCast(bool CStyle, SourceLocation Loc,
1857 const Expr *SrcExpr, QualType DestType,
1859 QualType SrcType = SrcExpr->getType();
1861 // Not warning on reinterpret_cast, boolean, constant expressions, etc
1862 // are not explicit design choices, but consistent with GCC's behavior.
1863 // Feel free to modify them if you've reason/evidence for an alternative.
1864 if (CStyle && SrcType->isIntegralType(Self.Context)
1865 && !SrcType->isBooleanType()
1866 && !SrcType->isEnumeralType()
1867 && !SrcExpr->isIntegerConstantExpr(Self.Context)
1868 && Self.Context.getTypeSize(DestType) >
1869 Self.Context.getTypeSize(SrcType)) {
1870 // Separate between casts to void* and non-void* pointers.
1871 // Some APIs use (abuse) void* for something like a user context,
1872 // and often that value is an integer even if it isn't a pointer itself.
1873 // Having a separate warning flag allows users to control the warning
1874 // for their workflow.
1875 unsigned Diag = DestType->isVoidPointerType() ?
1876 diag::warn_int_to_void_pointer_cast
1877 : diag::warn_int_to_pointer_cast;
1878 Self.Diag(Loc, Diag) << SrcType << DestType;
1882 static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
1883 ExprResult &Result) {
1884 // We can only fix an overloaded reinterpret_cast if
1885 // - it is a template with explicit arguments that resolves to an lvalue
1886 // unambiguously, or
1887 // - it is the only function in an overload set that may have its address
1890 Expr *E = Result.get();
1891 // TODO: what if this fails because of DiagnoseUseOfDecl or something
1893 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
1895 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
1900 // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization
1901 // preserves Result.
1903 if (!Self.resolveAndFixAddressOfOnlyViableOverloadCandidate(
1904 Result, /*DoFunctionPointerConversion=*/true))
1906 return Result.isUsable();
1909 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
1910 QualType DestType, bool CStyle,
1911 SourceRange OpRange,
1914 bool IsLValueCast = false;
1916 DestType = Self.Context.getCanonicalType(DestType);
1917 QualType SrcType = SrcExpr.get()->getType();
1919 // Is the source an overloaded name? (i.e. &foo)
1920 // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
1921 if (SrcType == Self.Context.OverloadTy) {
1922 ExprResult FixedExpr = SrcExpr;
1923 if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr))
1924 return TC_NotApplicable;
1926 assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
1927 SrcExpr = FixedExpr;
1928 SrcType = SrcExpr.get()->getType();
1931 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
1932 if (!SrcExpr.get()->isGLValue()) {
1933 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
1934 // similar comment in const_cast.
1935 msg = diag::err_bad_cxx_cast_rvalue;
1936 return TC_NotApplicable;
1940 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
1941 /*isDereference=*/false, OpRange);
1944 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
1945 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
1946 // built-in & and * operators.
1948 const char *inappropriate = nullptr;
1949 switch (SrcExpr.get()->getObjectKind()) {
1953 msg = diag::err_bad_cxx_cast_bitfield;
1954 return TC_NotApplicable;
1955 // FIXME: Use a specific diagnostic for the rest of these cases.
1956 case OK_VectorComponent: inappropriate = "vector element"; break;
1957 case OK_ObjCProperty: inappropriate = "property expression"; break;
1958 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
1961 if (inappropriate) {
1962 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference)
1963 << inappropriate << DestType
1964 << OpRange << SrcExpr.get()->getSourceRange();
1965 msg = 0; SrcExpr = ExprError();
1966 return TC_NotApplicable;
1969 // This code does this transformation for the checked types.
1970 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1971 SrcType = Self.Context.getPointerType(SrcType);
1973 IsLValueCast = true;
1976 // Canonicalize source for comparison.
1977 SrcType = Self.Context.getCanonicalType(SrcType);
1979 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
1980 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1981 if (DestMemPtr && SrcMemPtr) {
1982 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
1983 // can be explicitly converted to an rvalue of type "pointer to member
1984 // of Y of type T2" if T1 and T2 are both function types or both object
1986 if (DestMemPtr->isMemberFunctionPointer() !=
1987 SrcMemPtr->isMemberFunctionPointer())
1988 return TC_NotApplicable;
1990 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
1992 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
1994 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
1995 /*CheckObjCLifetime=*/CStyle)) {
1996 msg = diag::err_bad_cxx_cast_qualifiers_away;
2000 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2001 // We need to determine the inheritance model that the class will use if
2003 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
2004 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
2007 // Don't allow casting between member pointers of different sizes.
2008 if (Self.Context.getTypeSize(DestMemPtr) !=
2009 Self.Context.getTypeSize(SrcMemPtr)) {
2010 msg = diag::err_bad_cxx_cast_member_pointer_size;
2014 // A valid member pointer cast.
2015 assert(!IsLValueCast);
2016 Kind = CK_ReinterpretMemberPointer;
2020 // See below for the enumeral issue.
2021 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) {
2022 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
2023 // type large enough to hold it. A value of std::nullptr_t can be
2024 // converted to an integral type; the conversion has the same meaning
2025 // and validity as a conversion of (void*)0 to the integral type.
2026 if (Self.Context.getTypeSize(SrcType) >
2027 Self.Context.getTypeSize(DestType)) {
2028 msg = diag::err_bad_reinterpret_cast_small_int;
2031 Kind = CK_PointerToIntegral;
2035 // Allow reinterpret_casts between vectors of the same size and
2036 // between vectors and integers of the same size.
2037 bool destIsVector = DestType->isVectorType();
2038 bool srcIsVector = SrcType->isVectorType();
2039 if (srcIsVector || destIsVector) {
2040 // The non-vector type, if any, must have integral type. This is
2041 // the same rule that C vector casts use; note, however, that enum
2042 // types are not integral in C++.
2043 if ((!destIsVector && !DestType->isIntegralType(Self.Context)) ||
2044 (!srcIsVector && !SrcType->isIntegralType(Self.Context)))
2045 return TC_NotApplicable;
2047 // The size we want to consider is eltCount * eltSize.
2048 // That's exactly what the lax-conversion rules will check.
2049 if (Self.areLaxCompatibleVectorTypes(SrcType, DestType)) {
2054 // Otherwise, pick a reasonable diagnostic.
2056 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
2057 else if (!srcIsVector)
2058 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
2060 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
2065 if (SrcType == DestType) {
2066 // C++ 5.2.10p2 has a note that mentions that, subject to all other
2067 // restrictions, a cast to the same type is allowed so long as it does not
2068 // cast away constness. In C++98, the intent was not entirely clear here,
2069 // since all other paragraphs explicitly forbid casts to the same type.
2070 // C++11 clarifies this case with p2.
2072 // The only allowed types are: integral, enumeration, pointer, or
2073 // pointer-to-member types. We also won't restrict Obj-C pointers either.
2075 TryCastResult Result = TC_NotApplicable;
2076 if (SrcType->isIntegralOrEnumerationType() ||
2077 SrcType->isAnyPointerType() ||
2078 SrcType->isMemberPointerType() ||
2079 SrcType->isBlockPointerType()) {
2080 Result = TC_Success;
2085 bool destIsPtr = DestType->isAnyPointerType() ||
2086 DestType->isBlockPointerType();
2087 bool srcIsPtr = SrcType->isAnyPointerType() ||
2088 SrcType->isBlockPointerType();
2089 if (!destIsPtr && !srcIsPtr) {
2090 // Except for std::nullptr_t->integer and lvalue->reference, which are
2091 // handled above, at least one of the two arguments must be a pointer.
2092 return TC_NotApplicable;
2095 if (DestType->isIntegralType(Self.Context)) {
2096 assert(srcIsPtr && "One type must be a pointer");
2097 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
2098 // type large enough to hold it; except in Microsoft mode, where the
2099 // integral type size doesn't matter (except we don't allow bool).
2100 bool MicrosoftException = Self.getLangOpts().MicrosoftExt &&
2101 !DestType->isBooleanType();
2102 if ((Self.Context.getTypeSize(SrcType) >
2103 Self.Context.getTypeSize(DestType)) &&
2104 !MicrosoftException) {
2105 msg = diag::err_bad_reinterpret_cast_small_int;
2108 Kind = CK_PointerToIntegral;
2112 if (SrcType->isIntegralOrEnumerationType()) {
2113 assert(destIsPtr && "One type must be a pointer");
2114 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType,
2116 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
2117 // converted to a pointer.
2118 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
2119 // necessarily converted to a null pointer value.]
2120 Kind = CK_IntegralToPointer;
2124 if (!destIsPtr || !srcIsPtr) {
2125 // With the valid non-pointer conversions out of the way, we can be even
2127 return TC_NotApplicable;
2130 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
2131 // The C-style cast operator can.
2132 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2133 /*CheckObjCLifetime=*/CStyle)) {
2134 msg = diag::err_bad_cxx_cast_qualifiers_away;
2138 // Cannot convert between block pointers and Objective-C object pointers.
2139 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
2140 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
2141 return TC_NotApplicable;
2144 Kind = CK_LValueBitCast;
2145 } else if (DestType->isObjCObjectPointerType()) {
2146 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
2147 } else if (DestType->isBlockPointerType()) {
2148 if (!SrcType->isBlockPointerType()) {
2149 Kind = CK_AnyPointerToBlockPointerCast;
2157 // Any pointer can be cast to an Objective-C pointer type with a C-style
2159 if (CStyle && DestType->isObjCObjectPointerType()) {
2163 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2165 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2167 // Not casting away constness, so the only remaining check is for compatible
2168 // pointer categories.
2170 if (SrcType->isFunctionPointerType()) {
2171 if (DestType->isFunctionPointerType()) {
2172 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
2173 // a pointer to a function of a different type.
2177 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
2178 // an object type or vice versa is conditionally-supported.
2179 // Compilers support it in C++03 too, though, because it's necessary for
2180 // casting the return value of dlsym() and GetProcAddress().
2181 // FIXME: Conditionally-supported behavior should be configurable in the
2182 // TargetInfo or similar.
2183 Self.Diag(OpRange.getBegin(),
2184 Self.getLangOpts().CPlusPlus11 ?
2185 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2190 if (DestType->isFunctionPointerType()) {
2192 Self.Diag(OpRange.getBegin(),
2193 Self.getLangOpts().CPlusPlus11 ?
2194 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2199 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
2200 // a pointer to an object of different type.
2201 // Void pointers are not specified, but supported by every compiler out there.
2202 // So we finish by allowing everything that remains - it's got to be two
2207 void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2208 bool ListInitialization) {
2209 assert(Self.getLangOpts().CPlusPlus);
2211 // Handle placeholders.
2212 if (isPlaceholder()) {
2213 // C-style casts can resolve __unknown_any types.
2214 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2215 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2216 SrcExpr.get(), Kind,
2217 ValueKind, BasePath);
2221 checkNonOverloadPlaceholders();
2222 if (SrcExpr.isInvalid())
2226 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2227 // This test is outside everything else because it's the only case where
2228 // a non-lvalue-reference target type does not lead to decay.
2229 if (DestType->isVoidType()) {
2232 if (claimPlaceholder(BuiltinType::Overload)) {
2233 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2234 SrcExpr, /* Decay Function to ptr */ false,
2235 /* Complain */ true, DestRange, DestType,
2236 diag::err_bad_cstyle_cast_overload);
2237 if (SrcExpr.isInvalid())
2241 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2245 // If the type is dependent, we won't do any other semantic analysis now.
2246 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2247 SrcExpr.get()->isValueDependent()) {
2248 assert(Kind == CK_Dependent);
2252 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
2253 !isPlaceholder(BuiltinType::Overload)) {
2254 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2255 if (SrcExpr.isInvalid())
2259 // AltiVec vector initialization with a single literal.
2260 if (const VectorType *vecTy = DestType->getAs<VectorType>())
2261 if (vecTy->getVectorKind() == VectorType::AltiVecVector
2262 && (SrcExpr.get()->getType()->isIntegerType()
2263 || SrcExpr.get()->getType()->isFloatingType())) {
2264 Kind = CK_VectorSplat;
2265 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2269 // C++ [expr.cast]p5: The conversions performed by
2272 // - a static_cast followed by a const_cast,
2273 // - a reinterpret_cast, or
2274 // - a reinterpret_cast followed by a const_cast,
2275 // can be performed using the cast notation of explicit type conversion.
2276 // [...] If a conversion can be interpreted in more than one of the ways
2277 // listed above, the interpretation that appears first in the list is used,
2278 // even if a cast resulting from that interpretation is ill-formed.
2279 // In plain language, this means trying a const_cast ...
2280 unsigned msg = diag::err_bad_cxx_cast_generic;
2281 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2282 /*CStyle*/true, msg);
2283 if (SrcExpr.isInvalid())
2285 if (tcr == TC_Success)
2288 Sema::CheckedConversionKind CCK
2289 = FunctionalStyle? Sema::CCK_FunctionalCast
2290 : Sema::CCK_CStyleCast;
2291 if (tcr == TC_NotApplicable) {
2292 // ... or if that is not possible, a static_cast, ignoring const, ...
2293 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange,
2294 msg, Kind, BasePath, ListInitialization);
2295 if (SrcExpr.isInvalid())
2298 if (tcr == TC_NotApplicable) {
2299 // ... and finally a reinterpret_cast, ignoring const.
2300 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true,
2301 OpRange, msg, Kind);
2302 if (SrcExpr.isInvalid())
2307 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
2309 checkObjCConversion(CCK);
2311 if (tcr != TC_Success && msg != 0) {
2312 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2313 DeclAccessPair Found;
2314 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
2319 // If DestType is a function type (not to be confused with the function
2320 // pointer type), it will be possible to resolve the function address,
2321 // but the type cast should be considered as failure.
2322 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression;
2323 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload)
2324 << OE->getName() << DestType << OpRange
2325 << OE->getQualifierLoc().getSourceRange();
2326 Self.NoteAllOverloadCandidates(SrcExpr.get());
2329 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle),
2330 OpRange, SrcExpr.get(), DestType, ListInitialization);
2332 } else if (Kind == CK_BitCast) {
2336 // Clear out SrcExpr if there was a fatal error.
2337 if (tcr != TC_Success)
2338 SrcExpr = ExprError();
2341 /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2342 /// non-matching type. Such as enum function call to int, int call to
2343 /// pointer; etc. Cast to 'void' is an exception.
2344 static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2345 QualType DestType) {
2346 if (Self.Diags.isIgnored(diag::warn_bad_function_cast,
2347 SrcExpr.get()->getExprLoc()))
2350 if (!isa<CallExpr>(SrcExpr.get()))
2353 QualType SrcType = SrcExpr.get()->getType();
2354 if (DestType.getUnqualifiedType()->isVoidType())
2356 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2357 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2359 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2360 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2361 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2363 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2365 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2367 if (SrcType->isComplexType() && DestType->isComplexType())
2369 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2372 Self.Diag(SrcExpr.get()->getExprLoc(),
2373 diag::warn_bad_function_cast)
2374 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2377 /// Check the semantics of a C-style cast operation, in C.
2378 void CastOperation::CheckCStyleCast() {
2379 assert(!Self.getLangOpts().CPlusPlus);
2381 // C-style casts can resolve __unknown_any types.
2382 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2383 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2384 SrcExpr.get(), Kind,
2385 ValueKind, BasePath);
2389 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
2390 // type needs to be scalar.
2391 if (DestType->isVoidType()) {
2392 // We don't necessarily do lvalue-to-rvalue conversions on this.
2393 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2394 if (SrcExpr.isInvalid())
2397 // Cast to void allows any expr type.
2402 // Overloads are allowed with C extensions, so we need to support them.
2403 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2405 if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction(
2406 SrcExpr.get(), DestType, /*Complain=*/true, DAP))
2407 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr.get(), DAP, FD);
2410 assert(SrcExpr.isUsable());
2412 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2413 if (SrcExpr.isInvalid())
2415 QualType SrcType = SrcExpr.get()->getType();
2417 assert(!SrcType->isPlaceholderType());
2419 // OpenCL v1 s6.5: Casting a pointer to address space A to a pointer to
2420 // address space B is illegal.
2421 if (Self.getLangOpts().OpenCL && DestType->isPointerType() &&
2422 SrcType->isPointerType()) {
2423 const PointerType *DestPtr = DestType->getAs<PointerType>();
2424 if (!DestPtr->isAddressSpaceOverlapping(*SrcType->getAs<PointerType>())) {
2425 Self.Diag(OpRange.getBegin(),
2426 diag::err_typecheck_incompatible_address_space)
2427 << SrcType << DestType << Sema::AA_Casting
2428 << SrcExpr.get()->getSourceRange();
2429 SrcExpr = ExprError();
2434 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2435 diag::err_typecheck_cast_to_incomplete)) {
2436 SrcExpr = ExprError();
2440 if (!DestType->isScalarType() && !DestType->isVectorType()) {
2441 const RecordType *DestRecordTy = DestType->getAs<RecordType>();
2443 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){
2444 // GCC struct/union extension: allow cast to self.
2445 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar)
2446 << DestType << SrcExpr.get()->getSourceRange();
2451 // GCC's cast to union extension.
2452 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) {
2453 RecordDecl *RD = DestRecordTy->getDecl();
2454 RecordDecl::field_iterator Field, FieldEnd;
2455 for (Field = RD->field_begin(), FieldEnd = RD->field_end();
2456 Field != FieldEnd; ++Field) {
2457 if (Self.Context.hasSameUnqualifiedType(Field->getType(), SrcType) &&
2458 !Field->isUnnamedBitfield()) {
2459 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union)
2460 << SrcExpr.get()->getSourceRange();
2464 if (Field == FieldEnd) {
2465 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type)
2466 << SrcType << SrcExpr.get()->getSourceRange();
2467 SrcExpr = ExprError();
2474 // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type.
2475 if (Self.getLangOpts().OpenCL && DestType->isEventT()) {
2476 llvm::APSInt CastInt;
2477 if (SrcExpr.get()->EvaluateAsInt(CastInt, Self.Context)) {
2479 Kind = CK_ZeroToOCLEvent;
2482 Self.Diag(OpRange.getBegin(),
2483 diag::err_opencl_cast_non_zero_to_event_t)
2484 << CastInt.toString(10) << SrcExpr.get()->getSourceRange();
2485 SrcExpr = ExprError();
2490 // Reject any other conversions to non-scalar types.
2491 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar)
2492 << DestType << SrcExpr.get()->getSourceRange();
2493 SrcExpr = ExprError();
2497 // The type we're casting to is known to be a scalar or vector.
2499 // Require the operand to be a scalar or vector.
2500 if (!SrcType->isScalarType() && !SrcType->isVectorType()) {
2501 Self.Diag(SrcExpr.get()->getExprLoc(),
2502 diag::err_typecheck_expect_scalar_operand)
2503 << SrcType << SrcExpr.get()->getSourceRange();
2504 SrcExpr = ExprError();
2508 if (DestType->isExtVectorType()) {
2509 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind);
2513 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
2514 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector &&
2515 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
2516 Kind = CK_VectorSplat;
2517 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2518 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) {
2519 SrcExpr = ExprError();
2524 if (SrcType->isVectorType()) {
2525 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind))
2526 SrcExpr = ExprError();
2530 // The source and target types are both scalars, i.e.
2531 // - arithmetic types (fundamental, enum, and complex)
2532 // - all kinds of pointers
2533 // Note that member pointers were filtered out with C++, above.
2535 if (isa<ObjCSelectorExpr>(SrcExpr.get())) {
2536 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr);
2537 SrcExpr = ExprError();
2541 // If either type is a pointer, the other type has to be either an
2542 // integer or a pointer.
2543 if (!DestType->isArithmeticType()) {
2544 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) {
2545 Self.Diag(SrcExpr.get()->getExprLoc(),
2546 diag::err_cast_pointer_from_non_pointer_int)
2547 << SrcType << SrcExpr.get()->getSourceRange();
2548 SrcExpr = ExprError();
2551 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(),
2553 } else if (!SrcType->isArithmeticType()) {
2554 if (!DestType->isIntegralType(Self.Context) &&
2555 DestType->isArithmeticType()) {
2556 Self.Diag(SrcExpr.get()->getLocStart(),
2557 diag::err_cast_pointer_to_non_pointer_int)
2558 << DestType << SrcExpr.get()->getSourceRange();
2559 SrcExpr = ExprError();
2564 if (Self.getLangOpts().OpenCL &&
2565 !Self.getOpenCLOptions().isEnabled("cl_khr_fp16")) {
2566 if (DestType->isHalfType()) {
2567 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half)
2568 << DestType << SrcExpr.get()->getSourceRange();
2569 SrcExpr = ExprError();
2574 // ARC imposes extra restrictions on casts.
2575 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) {
2576 checkObjCConversion(Sema::CCK_CStyleCast);
2577 if (SrcExpr.isInvalid())
2580 const PointerType *CastPtr = DestType->getAs<PointerType>();
2581 if (Self.getLangOpts().ObjCAutoRefCount && CastPtr) {
2582 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
2583 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
2584 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
2585 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
2586 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
2587 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) {
2588 Self.Diag(SrcExpr.get()->getLocStart(),
2589 diag::err_typecheck_incompatible_ownership)
2590 << SrcType << DestType << Sema::AA_Casting
2591 << SrcExpr.get()->getSourceRange();
2596 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) {
2597 Self.Diag(SrcExpr.get()->getLocStart(),
2598 diag::err_arc_convesion_of_weak_unavailable)
2599 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2600 SrcExpr = ExprError();
2605 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2606 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2607 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
2608 Kind = Self.PrepareScalarCast(SrcExpr, DestType);
2609 if (SrcExpr.isInvalid())
2612 if (Kind == CK_BitCast)
2616 /// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
2617 /// const, volatile or both.
2618 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
2619 QualType DestType) {
2620 if (SrcExpr.isInvalid())
2623 QualType SrcType = SrcExpr.get()->getType();
2624 if (!((SrcType->isAnyPointerType() && DestType->isAnyPointerType()) ||
2625 DestType->isLValueReferenceType()))
2628 QualType TheOffendingSrcType, TheOffendingDestType;
2629 Qualifiers CastAwayQualifiers;
2630 if (!CastsAwayConstness(Self, SrcType, DestType, true, false,
2631 &TheOffendingSrcType, &TheOffendingDestType,
2632 &CastAwayQualifiers))
2635 int qualifiers = -1;
2636 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
2638 } else if (CastAwayQualifiers.hasConst()) {
2640 } else if (CastAwayQualifiers.hasVolatile()) {
2643 // This is a variant of int **x; const int **y = (const int **)x;
2644 if (qualifiers == -1)
2645 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual2)
2646 << SrcType << DestType;
2648 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual)
2649 << TheOffendingSrcType << TheOffendingDestType << qualifiers;
2652 ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
2653 TypeSourceInfo *CastTypeInfo,
2654 SourceLocation RPLoc,
2656 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
2657 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2658 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd());
2660 if (getLangOpts().CPlusPlus) {
2661 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false,
2662 isa<InitListExpr>(CastExpr));
2664 Op.CheckCStyleCast();
2667 if (Op.SrcExpr.isInvalid())
2671 DiagnoseCastQual(Op.Self, Op.SrcExpr, Op.DestType);
2673 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType,
2674 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
2675 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc));
2678 ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
2680 SourceLocation LPLoc,
2682 SourceLocation RPLoc) {
2683 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
2684 CastOperation Op(*this, Type, CastExpr);
2685 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2686 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd());
2688 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false);
2689 if (Op.SrcExpr.isInvalid())
2692 auto *SubExpr = Op.SrcExpr.get();
2693 if (auto *BindExpr = dyn_cast<CXXBindTemporaryExpr>(SubExpr))
2694 SubExpr = BindExpr->getSubExpr();
2695 if (auto *ConstructExpr = dyn_cast<CXXConstructExpr>(SubExpr))
2696 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc));
2698 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType,
2699 Op.ValueKind, CastTypeInfo, Op.Kind,
2700 Op.SrcExpr.get(), &Op.BasePath, LPLoc, RPLoc));