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/Sema/Initialization.h"
26 #include "llvm/ADT/SmallVector.h"
28 using namespace clang;
33 TC_NotApplicable, ///< The cast method is not applicable.
34 TC_Success, ///< The cast method is appropriate and successful.
35 TC_Failed ///< The cast method is appropriate, but failed. A
36 ///< diagnostic has been emitted.
40 CT_Const, ///< const_cast
41 CT_Static, ///< static_cast
42 CT_Reinterpret, ///< reinterpret_cast
43 CT_Dynamic, ///< dynamic_cast
44 CT_CStyle, ///< (Type)expr
45 CT_Functional ///< Type(expr)
49 struct CastOperation {
50 CastOperation(Sema &S, QualType destType, ExprResult src)
51 : Self(S), SrcExpr(src), DestType(destType),
52 ResultType(destType.getNonLValueExprType(S.Context)),
53 ValueKind(Expr::getValueKindForType(destType)),
54 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
56 if (const BuiltinType *placeholder =
57 src.get()->getType()->getAsPlaceholderType()) {
58 PlaceholderKind = placeholder->getKind();
60 PlaceholderKind = (BuiltinType::Kind) 0;
68 ExprValueKind ValueKind;
70 BuiltinType::Kind PlaceholderKind;
72 bool IsARCUnbridgedCast;
75 SourceRange DestRange;
77 // Top-level semantics-checking routines.
78 void CheckConstCast();
79 void CheckReinterpretCast();
80 void CheckStaticCast();
81 void CheckDynamicCast();
82 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
83 void CheckCStyleCast();
85 /// Complete an apparently-successful cast operation that yields
86 /// the given expression.
87 ExprResult complete(CastExpr *castExpr) {
88 // If this is an unbridged cast, wrap the result in an implicit
89 // cast that yields the unbridged-cast placeholder type.
90 if (IsARCUnbridgedCast) {
91 castExpr = ImplicitCastExpr::Create(Self.Context,
92 Self.Context.ARCUnbridgedCastTy,
93 CK_Dependent, castExpr, nullptr,
94 castExpr->getValueKind());
99 // Internal convenience methods.
101 /// Try to handle the given placeholder expression kind. Return
102 /// true if the source expression has the appropriate placeholder
103 /// kind. A placeholder can only be claimed once.
104 bool claimPlaceholder(BuiltinType::Kind K) {
105 if (PlaceholderKind != K) return false;
107 PlaceholderKind = (BuiltinType::Kind) 0;
111 bool isPlaceholder() const {
112 return PlaceholderKind != 0;
114 bool isPlaceholder(BuiltinType::Kind K) const {
115 return PlaceholderKind == K;
118 void checkCastAlign() {
119 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
122 void checkObjCARCConversion(Sema::CheckedConversionKind CCK) {
123 assert(Self.getLangOpts().ObjCAutoRefCount);
125 Expr *src = SrcExpr.get();
126 if (Self.CheckObjCARCConversion(OpRange, DestType, src, CCK) ==
128 IsARCUnbridgedCast = true;
132 /// Check for and handle non-overload placeholder expressions.
133 void checkNonOverloadPlaceholders() {
134 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload))
137 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
138 if (SrcExpr.isInvalid())
140 PlaceholderKind = (BuiltinType::Kind) 0;
145 static bool CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
146 bool CheckCVR, bool CheckObjCLifetime);
148 // The Try functions attempt a specific way of casting. If they succeed, they
149 // return TC_Success. If their way of casting is not appropriate for the given
150 // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
151 // to emit if no other way succeeds. If their way of casting is appropriate but
152 // fails, they return TC_Failed and *must* set diag; they can set it to 0 if
153 // they emit a specialized diagnostic.
154 // All diagnostics returned by these functions must expect the same three
156 // %0: Cast Type (a value from the CastType enumeration)
158 // %2: Destination Type
159 static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
160 QualType DestType, bool CStyle,
162 CXXCastPath &BasePath,
164 static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
165 QualType DestType, bool CStyle,
166 const SourceRange &OpRange,
169 CXXCastPath &BasePath);
170 static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
171 QualType DestType, bool CStyle,
172 const SourceRange &OpRange,
175 CXXCastPath &BasePath);
176 static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
177 CanQualType DestType, bool CStyle,
178 const SourceRange &OpRange,
179 QualType OrigSrcType,
180 QualType OrigDestType, unsigned &msg,
182 CXXCastPath &BasePath);
183 static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
185 QualType DestType,bool CStyle,
186 const SourceRange &OpRange,
189 CXXCastPath &BasePath);
191 static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
193 Sema::CheckedConversionKind CCK,
194 const SourceRange &OpRange,
195 unsigned &msg, CastKind &Kind,
196 bool ListInitialization);
197 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
199 Sema::CheckedConversionKind CCK,
200 const SourceRange &OpRange,
201 unsigned &msg, CastKind &Kind,
202 CXXCastPath &BasePath,
203 bool ListInitialization);
204 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
205 QualType DestType, bool CStyle,
207 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
208 QualType DestType, bool CStyle,
209 const SourceRange &OpRange,
214 /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
216 Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
217 SourceLocation LAngleBracketLoc, Declarator &D,
218 SourceLocation RAngleBracketLoc,
219 SourceLocation LParenLoc, Expr *E,
220 SourceLocation RParenLoc) {
222 assert(!D.isInvalidType());
224 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType());
225 if (D.isInvalidType())
228 if (getLangOpts().CPlusPlus) {
229 // Check that there are no default arguments (C++ only).
230 CheckExtraCXXDefaultArguments(D);
233 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E,
234 SourceRange(LAngleBracketLoc, RAngleBracketLoc),
235 SourceRange(LParenLoc, RParenLoc));
239 Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
240 TypeSourceInfo *DestTInfo, Expr *E,
241 SourceRange AngleBrackets, SourceRange Parens) {
243 QualType DestType = DestTInfo->getType();
245 // If the type is dependent, we won't do the semantic analysis now.
246 // FIXME: should we check this in a more fine-grained manner?
247 bool TypeDependent = DestType->isDependentType() ||
248 Ex.get()->isTypeDependent() ||
249 Ex.get()->isValueDependent();
251 CastOperation Op(*this, DestType, E);
252 Op.OpRange = SourceRange(OpLoc, Parens.getEnd());
253 Op.DestRange = AngleBrackets;
256 default: llvm_unreachable("Unknown C++ cast!");
258 case tok::kw_const_cast:
259 if (!TypeDependent) {
261 if (Op.SrcExpr.isInvalid())
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())
287 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
288 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
289 nullptr, DestTInfo, OpLoc,
293 case tok::kw_static_cast: {
294 if (!TypeDependent) {
295 Op.CheckStaticCast();
296 if (Op.SrcExpr.isInvalid())
300 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType,
301 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
302 &Op.BasePath, DestTInfo,
303 OpLoc, Parens.getEnd(),
309 /// Try to diagnose a failed overloaded cast. Returns true if
310 /// diagnostics were emitted.
311 static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
312 SourceRange range, Expr *src,
314 bool listInitialization) {
316 // These cast kinds don't consider user-defined conversions.
329 QualType srcType = src->getType();
330 if (!destType->isRecordType() && !srcType->isRecordType())
333 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType);
334 InitializationKind initKind
335 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(),
336 range, listInitialization)
337 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range,
339 : InitializationKind::CreateCast(/*type range?*/ range);
340 InitializationSequence sequence(S, entity, initKind, src);
342 assert(sequence.Failed() && "initialization succeeded on second try?");
343 switch (sequence.getFailureKind()) {
344 default: return false;
346 case InitializationSequence::FK_ConstructorOverloadFailed:
347 case InitializationSequence::FK_UserConversionOverloadFailed:
351 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
354 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
356 switch (sequence.getFailedOverloadResult()) {
357 case OR_Success: llvm_unreachable("successful failed overload");
358 case OR_No_Viable_Function:
359 if (candidates.empty())
360 msg = diag::err_ovl_no_conversion_in_cast;
362 msg = diag::err_ovl_no_viable_conversion_in_cast;
363 howManyCandidates = OCD_AllCandidates;
367 msg = diag::err_ovl_ambiguous_conversion_in_cast;
368 howManyCandidates = OCD_ViableCandidates;
372 msg = diag::err_ovl_deleted_conversion_in_cast;
373 howManyCandidates = OCD_ViableCandidates;
377 S.Diag(range.getBegin(), msg)
378 << CT << srcType << destType
379 << range << src->getSourceRange();
381 candidates.NoteCandidates(S, howManyCandidates, src);
386 /// Diagnose a failed cast.
387 static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
388 SourceRange opRange, Expr *src, QualType destType,
389 bool listInitialization) {
390 if (msg == diag::err_bad_cxx_cast_generic &&
391 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType,
395 S.Diag(opRange.getBegin(), msg) << castType
396 << src->getType() << destType << opRange << src->getSourceRange();
399 /// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes,
400 /// this removes one level of indirection from both types, provided that they're
401 /// the same kind of pointer (plain or to-member). Unlike the Sema function,
402 /// this one doesn't care if the two pointers-to-member don't point into the
403 /// same class. This is because CastsAwayConstness doesn't care.
404 static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) {
405 const PointerType *T1PtrType = T1->getAs<PointerType>(),
406 *T2PtrType = T2->getAs<PointerType>();
407 if (T1PtrType && T2PtrType) {
408 T1 = T1PtrType->getPointeeType();
409 T2 = T2PtrType->getPointeeType();
412 const ObjCObjectPointerType *T1ObjCPtrType =
413 T1->getAs<ObjCObjectPointerType>(),
415 T2->getAs<ObjCObjectPointerType>();
418 T1 = T1ObjCPtrType->getPointeeType();
419 T2 = T2ObjCPtrType->getPointeeType();
422 else if (T2PtrType) {
423 T1 = T1ObjCPtrType->getPointeeType();
424 T2 = T2PtrType->getPointeeType();
428 else if (T2ObjCPtrType) {
430 T2 = T2ObjCPtrType->getPointeeType();
431 T1 = T1PtrType->getPointeeType();
436 const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(),
437 *T2MPType = T2->getAs<MemberPointerType>();
438 if (T1MPType && T2MPType) {
439 T1 = T1MPType->getPointeeType();
440 T2 = T2MPType->getPointeeType();
444 const BlockPointerType *T1BPType = T1->getAs<BlockPointerType>(),
445 *T2BPType = T2->getAs<BlockPointerType>();
446 if (T1BPType && T2BPType) {
447 T1 = T1BPType->getPointeeType();
448 T2 = T2BPType->getPointeeType();
455 /// CastsAwayConstness - Check if the pointer conversion from SrcType to
456 /// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by
457 /// the cast checkers. Both arguments must denote pointer (possibly to member)
460 /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
462 /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
464 CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
465 bool CheckCVR, bool CheckObjCLifetime) {
466 // If the only checking we care about is for Objective-C lifetime qualifiers,
467 // and we're not in ARC mode, there's nothing to check.
468 if (!CheckCVR && CheckObjCLifetime &&
469 !Self.Context.getLangOpts().ObjCAutoRefCount)
472 // Casting away constness is defined in C++ 5.2.11p8 with reference to
473 // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since
474 // the rules are non-trivial. So first we construct Tcv *...cv* as described
476 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
477 SrcType->isBlockPointerType()) &&
478 "Source type is not pointer or pointer to member.");
479 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
480 DestType->isBlockPointerType()) &&
481 "Destination type is not pointer or pointer to member.");
483 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
484 UnwrappedDestType = Self.Context.getCanonicalType(DestType);
485 SmallVector<Qualifiers, 8> cv1, cv2;
487 // Find the qualifiers. We only care about cvr-qualifiers for the
488 // purpose of this check, because other qualifiers (address spaces,
489 // Objective-C GC, etc.) are part of the type's identity.
490 while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
491 // Determine the relevant qualifiers at this level.
492 Qualifiers SrcQuals, DestQuals;
493 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals);
494 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals);
496 Qualifiers RetainedSrcQuals, RetainedDestQuals;
498 RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers());
499 RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers());
502 if (CheckObjCLifetime &&
503 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals))
506 cv1.push_back(RetainedSrcQuals);
507 cv2.push_back(RetainedDestQuals);
512 // Construct void pointers with those qualifiers (in reverse order of
513 // unwrapping, of course).
514 QualType SrcConstruct = Self.Context.VoidTy;
515 QualType DestConstruct = Self.Context.VoidTy;
516 ASTContext &Context = Self.Context;
517 for (SmallVectorImpl<Qualifiers>::reverse_iterator i1 = cv1.rbegin(),
519 i1 != cv1.rend(); ++i1, ++i2) {
521 = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1));
523 = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2));
526 // Test if they're compatible.
527 bool ObjCLifetimeConversion;
528 return SrcConstruct != DestConstruct &&
529 !Self.IsQualificationConversion(SrcConstruct, DestConstruct, false,
530 ObjCLifetimeConversion);
533 /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
534 /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
535 /// checked downcasts in class hierarchies.
536 void CastOperation::CheckDynamicCast() {
537 if (ValueKind == VK_RValue)
538 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
539 else if (isPlaceholder())
540 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
541 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
544 QualType OrigSrcType = SrcExpr.get()->getType();
545 QualType DestType = Self.Context.getCanonicalType(this->DestType);
547 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
548 // or "pointer to cv void".
550 QualType DestPointee;
551 const PointerType *DestPointer = DestType->getAs<PointerType>();
552 const ReferenceType *DestReference = nullptr;
554 DestPointee = DestPointer->getPointeeType();
555 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
556 DestPointee = DestReference->getPointeeType();
558 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
559 << this->DestType << DestRange;
560 SrcExpr = ExprError();
564 const RecordType *DestRecord = DestPointee->getAs<RecordType>();
565 if (DestPointee->isVoidType()) {
566 assert(DestPointer && "Reference to void is not possible");
567 } else if (DestRecord) {
568 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee,
569 diag::err_bad_dynamic_cast_incomplete,
571 SrcExpr = ExprError();
575 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
576 << DestPointee.getUnqualifiedType() << DestRange;
577 SrcExpr = ExprError();
581 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
582 // complete class type, [...]. If T is an lvalue reference type, v shall be
583 // an lvalue of a complete class type, [...]. If T is an rvalue reference
584 // type, v shall be an expression having a complete class type, [...]
585 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
588 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
589 SrcPointee = SrcPointer->getPointeeType();
591 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
592 << OrigSrcType << SrcExpr.get()->getSourceRange();
593 SrcExpr = ExprError();
596 } else if (DestReference->isLValueReferenceType()) {
597 if (!SrcExpr.get()->isLValue()) {
598 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
599 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
601 SrcPointee = SrcType;
603 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
604 // to materialize the prvalue before we bind the reference to it.
605 if (SrcExpr.get()->isRValue())
606 SrcExpr = new (Self.Context) MaterializeTemporaryExpr(
607 SrcType, SrcExpr.get(), /*IsLValueReference*/false);
608 SrcPointee = SrcType;
611 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
613 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
614 diag::err_bad_dynamic_cast_incomplete,
616 SrcExpr = ExprError();
620 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
621 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
622 SrcExpr = ExprError();
626 assert((DestPointer || DestReference) &&
627 "Bad destination non-ptr/ref slipped through.");
628 assert((DestRecord || DestPointee->isVoidType()) &&
629 "Bad destination pointee slipped through.");
630 assert(SrcRecord && "Bad source pointee slipped through.");
632 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
633 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
634 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away)
635 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
636 SrcExpr = ExprError();
640 // C++ 5.2.7p3: If the type of v is the same as the required result type,
642 if (DestRecord == SrcRecord) {
648 // Upcasts are resolved statically.
649 if (DestRecord && Self.IsDerivedFrom(SrcPointee, DestPointee)) {
650 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
651 OpRange.getBegin(), OpRange,
653 SrcExpr = ExprError();
657 Kind = CK_DerivedToBase;
659 // If we are casting to or through a virtual base class, we need a
661 if (Self.BasePathInvolvesVirtualBase(BasePath))
662 Self.MarkVTableUsed(OpRange.getBegin(),
663 cast<CXXRecordDecl>(SrcRecord->getDecl()));
667 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
668 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
669 assert(SrcDecl && "Definition missing");
670 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
671 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
672 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
673 SrcExpr = ExprError();
675 Self.MarkVTableUsed(OpRange.getBegin(),
676 cast<CXXRecordDecl>(SrcRecord->getDecl()));
678 // dynamic_cast is not available with -fno-rtti.
679 // As an exception, dynamic_cast to void* is available because it doesn't
681 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
682 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti);
683 SrcExpr = ExprError();
687 // Done. Everything else is run-time checks.
691 /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
692 /// Refer to C++ 5.2.11 for details. const_cast is typically used in code
694 /// const char *str = "literal";
695 /// legacy_function(const_cast\<char*\>(str));
696 void CastOperation::CheckConstCast() {
697 if (ValueKind == VK_RValue)
698 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
699 else if (isPlaceholder())
700 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
701 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
704 unsigned msg = diag::err_bad_cxx_cast_generic;
705 if (TryConstCast(Self, SrcExpr, DestType, /*CStyle*/false, msg) != TC_Success
707 Self.Diag(OpRange.getBegin(), msg) << CT_Const
708 << SrcExpr.get()->getType() << DestType << OpRange;
709 SrcExpr = ExprError();
713 /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
714 /// or downcast between respective pointers or references.
715 static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
717 SourceRange OpRange) {
718 QualType SrcType = SrcExpr->getType();
719 // When casting from pointer or reference, get pointee type; use original
721 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
722 const CXXRecordDecl *SrcRD =
723 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
725 // Examining subobjects for records is only possible if the complete and
726 // valid definition is available. Also, template instantiation is not
728 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
731 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
733 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
741 CXXBasePaths BasePaths;
743 if (SrcRD->isDerivedFrom(DestRD, BasePaths))
744 ReinterpretKind = ReinterpretUpcast;
745 else if (DestRD->isDerivedFrom(SrcRD, BasePaths))
746 ReinterpretKind = ReinterpretDowncast;
750 bool VirtualBase = true;
751 bool NonZeroOffset = false;
752 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
755 const CXXBasePath &Path = *I;
756 CharUnits Offset = CharUnits::Zero();
757 bool IsVirtual = false;
758 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
759 IElem != EElem; ++IElem) {
760 IsVirtual = IElem->Base->isVirtual();
763 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
764 assert(BaseRD && "Base type should be a valid unqualified class type");
765 // Don't check if any base has invalid declaration or has no definition
766 // since it has no layout info.
767 const CXXRecordDecl *Class = IElem->Class,
768 *ClassDefinition = Class->getDefinition();
769 if (Class->isInvalidDecl() || !ClassDefinition ||
770 !ClassDefinition->isCompleteDefinition())
773 const ASTRecordLayout &DerivedLayout =
774 Self.Context.getASTRecordLayout(Class);
775 Offset += DerivedLayout.getBaseClassOffset(BaseRD);
778 // Don't warn if any path is a non-virtually derived base at offset zero.
781 // Offset makes sense only for non-virtual bases.
783 NonZeroOffset = true;
785 VirtualBase = VirtualBase && IsVirtual;
788 (void) NonZeroOffset; // Silence set but not used warning.
789 assert((VirtualBase || NonZeroOffset) &&
790 "Should have returned if has non-virtual base with zero offset");
793 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
794 QualType DerivedType =
795 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
797 SourceLocation BeginLoc = OpRange.getBegin();
798 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static)
799 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
801 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static)
802 << int(ReinterpretKind)
803 << FixItHint::CreateReplacement(BeginLoc, "static_cast");
806 /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
808 /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
810 /// char *bytes = reinterpret_cast\<char*\>(int_ptr);
811 void CastOperation::CheckReinterpretCast() {
812 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload))
813 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
815 checkNonOverloadPlaceholders();
816 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
819 unsigned msg = diag::err_bad_cxx_cast_generic;
821 TryReinterpretCast(Self, SrcExpr, DestType,
822 /*CStyle*/false, OpRange, msg, Kind);
823 if (tcr != TC_Success && msg != 0)
825 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
827 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
828 //FIXME: &f<int>; is overloaded and resolvable
829 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload)
830 << OverloadExpr::find(SrcExpr.get()).Expression->getName()
831 << DestType << OpRange;
832 Self.NoteAllOverloadCandidates(SrcExpr.get());
835 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(),
836 DestType, /*listInitialization=*/false);
838 SrcExpr = ExprError();
839 } else if (tcr == TC_Success) {
840 if (Self.getLangOpts().ObjCAutoRefCount)
841 checkObjCARCConversion(Sema::CCK_OtherCast);
842 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
847 /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
848 /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
849 /// implicit conversions explicit and getting rid of data loss warnings.
850 void CastOperation::CheckStaticCast() {
851 if (isPlaceholder()) {
852 checkNonOverloadPlaceholders();
853 if (SrcExpr.isInvalid())
857 // This test is outside everything else because it's the only case where
858 // a non-lvalue-reference target type does not lead to decay.
859 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
860 if (DestType->isVoidType()) {
863 if (claimPlaceholder(BuiltinType::Overload)) {
864 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
865 false, // Decay Function to ptr
867 OpRange, DestType, diag::err_bad_static_cast_overload);
868 if (SrcExpr.isInvalid())
872 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
876 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
877 !isPlaceholder(BuiltinType::Overload)) {
878 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
879 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
883 unsigned msg = diag::err_bad_cxx_cast_generic;
885 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg,
886 Kind, BasePath, /*ListInitialization=*/false);
887 if (tcr != TC_Success && msg != 0) {
888 if (SrcExpr.isInvalid())
890 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
891 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression;
892 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload)
893 << oe->getName() << DestType << OpRange
894 << oe->getQualifierLoc().getSourceRange();
895 Self.NoteAllOverloadCandidates(SrcExpr.get());
897 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType,
898 /*listInitialization=*/false);
900 SrcExpr = ExprError();
901 } else if (tcr == TC_Success) {
902 if (Kind == CK_BitCast)
904 if (Self.getLangOpts().ObjCAutoRefCount)
905 checkObjCARCConversion(Sema::CCK_OtherCast);
906 } else if (Kind == CK_BitCast) {
911 /// TryStaticCast - Check if a static cast can be performed, and do so if
912 /// possible. If @p CStyle, ignore access restrictions on hierarchy casting
913 /// and casting away constness.
914 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
916 Sema::CheckedConversionKind CCK,
917 const SourceRange &OpRange, unsigned &msg,
918 CastKind &Kind, CXXCastPath &BasePath,
919 bool ListInitialization) {
920 // Determine whether we have the semantics of a C-style cast.
922 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
924 // The order the tests is not entirely arbitrary. There is one conversion
925 // that can be handled in two different ways. Given:
927 // struct B : public A {
931 // the cast static_cast<const B&>(a) could be seen as either a static
932 // reference downcast, or an explicit invocation of the user-defined
933 // conversion using B's conversion constructor.
934 // DR 427 specifies that the downcast is to be applied here.
936 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
937 // Done outside this function.
941 // C++ 5.2.9p5, reference downcast.
942 // See the function for details.
943 // DR 427 specifies that this is to be applied before paragraph 2.
944 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle,
945 OpRange, msg, Kind, BasePath);
946 if (tcr != TC_NotApplicable)
949 // C++0x [expr.static.cast]p3:
950 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
951 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
952 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind,
954 if (tcr != TC_NotApplicable)
957 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
958 // [...] if the declaration "T t(e);" is well-formed, [...].
959 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
960 Kind, ListInitialization);
961 if (SrcExpr.isInvalid())
963 if (tcr != TC_NotApplicable)
966 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
967 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
968 // conversions, subject to further restrictions.
969 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
970 // of qualification conversions impossible.
971 // In the CStyle case, the earlier attempt to const_cast should have taken
972 // care of reverse qualification conversions.
974 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType());
976 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
977 // converted to an integral type. [...] A value of a scoped enumeration type
978 // can also be explicitly converted to a floating-point type [...].
979 if (const EnumType *Enum = SrcType->getAs<EnumType>()) {
980 if (Enum->getDecl()->isScoped()) {
981 if (DestType->isBooleanType()) {
982 Kind = CK_IntegralToBoolean;
984 } else if (DestType->isIntegralType(Self.Context)) {
985 Kind = CK_IntegralCast;
987 } else if (DestType->isRealFloatingType()) {
988 Kind = CK_IntegralToFloating;
994 // Reverse integral promotion/conversion. All such conversions are themselves
995 // again integral promotions or conversions and are thus already handled by
996 // p2 (TryDirectInitialization above).
997 // (Note: any data loss warnings should be suppressed.)
998 // The exception is the reverse of enum->integer, i.e. integer->enum (and
999 // enum->enum). See also C++ 5.2.9p7.
1000 // The same goes for reverse floating point promotion/conversion and
1001 // floating-integral conversions. Again, only floating->enum is relevant.
1002 if (DestType->isEnumeralType()) {
1003 if (SrcType->isIntegralOrEnumerationType()) {
1004 Kind = CK_IntegralCast;
1006 } else if (SrcType->isRealFloatingType()) {
1007 Kind = CK_FloatingToIntegral;
1012 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1013 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1014 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1016 if (tcr != TC_NotApplicable)
1019 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1020 // conversion. C++ 5.2.9p9 has additional information.
1021 // DR54's access restrictions apply here also.
1022 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1023 OpRange, msg, Kind, BasePath);
1024 if (tcr != TC_NotApplicable)
1027 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1028 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1029 // just the usual constness stuff.
1030 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1031 QualType SrcPointee = SrcPointer->getPointeeType();
1032 if (SrcPointee->isVoidType()) {
1033 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1034 QualType DestPointee = DestPointer->getPointeeType();
1035 if (DestPointee->isIncompleteOrObjectType()) {
1036 // This is definitely the intended conversion, but it might fail due
1037 // to a qualifier violation. Note that we permit Objective-C lifetime
1038 // and GC qualifier mismatches here.
1040 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1041 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1042 DestPointeeQuals.removeObjCGCAttr();
1043 DestPointeeQuals.removeObjCLifetime();
1044 SrcPointeeQuals.removeObjCGCAttr();
1045 SrcPointeeQuals.removeObjCLifetime();
1046 if (DestPointeeQuals != SrcPointeeQuals &&
1047 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) {
1048 msg = diag::err_bad_cxx_cast_qualifiers_away;
1056 else if (DestType->isObjCObjectPointerType()) {
1057 // allow both c-style cast and static_cast of objective-c pointers as
1058 // they are pervasive.
1059 Kind = CK_CPointerToObjCPointerCast;
1062 else if (CStyle && DestType->isBlockPointerType()) {
1063 // allow c-style cast of void * to block pointers.
1064 Kind = CK_AnyPointerToBlockPointerCast;
1069 // Allow arbitray objective-c pointer conversion with static casts.
1070 if (SrcType->isObjCObjectPointerType() &&
1071 DestType->isObjCObjectPointerType()) {
1075 // Allow ns-pointer to cf-pointer conversion in either direction
1076 // with static casts.
1078 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
1081 // We tried everything. Everything! Nothing works! :-(
1082 return TC_NotApplicable;
1085 /// Tests whether a conversion according to N2844 is valid.
1087 TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, QualType DestType,
1088 bool CStyle, CastKind &Kind, CXXCastPath &BasePath,
1090 // C++0x [expr.static.cast]p3:
1091 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1092 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1093 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1095 return TC_NotApplicable;
1097 if (!SrcExpr->isGLValue())
1098 return TC_NotApplicable;
1100 // Because we try the reference downcast before this function, from now on
1101 // this is the only cast possibility, so we issue an error if we fail now.
1102 // FIXME: Should allow casting away constness if CStyle.
1104 bool ObjCConversion;
1105 bool ObjCLifetimeConversion;
1106 QualType FromType = SrcExpr->getType();
1107 QualType ToType = R->getPointeeType();
1109 FromType = FromType.getUnqualifiedType();
1110 ToType = ToType.getUnqualifiedType();
1113 if (Self.CompareReferenceRelationship(SrcExpr->getLocStart(),
1115 DerivedToBase, ObjCConversion,
1116 ObjCLifetimeConversion)
1117 < Sema::Ref_Compatible_With_Added_Qualification) {
1118 msg = diag::err_bad_lvalue_to_rvalue_cast;
1122 if (DerivedToBase) {
1123 Kind = CK_DerivedToBase;
1124 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1125 /*DetectVirtual=*/true);
1126 if (!Self.IsDerivedFrom(SrcExpr->getType(), R->getPointeeType(), Paths))
1127 return TC_NotApplicable;
1129 Self.BuildBasePathArray(Paths, BasePath);
1136 /// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1138 TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
1139 bool CStyle, const SourceRange &OpRange,
1140 unsigned &msg, CastKind &Kind,
1141 CXXCastPath &BasePath) {
1142 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1143 // cast to type "reference to cv2 D", where D is a class derived from B,
1144 // if a valid standard conversion from "pointer to D" to "pointer to B"
1145 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1146 // In addition, DR54 clarifies that the base must be accessible in the
1147 // current context. Although the wording of DR54 only applies to the pointer
1148 // variant of this rule, the intent is clearly for it to apply to the this
1149 // conversion as well.
1151 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1152 if (!DestReference) {
1153 return TC_NotApplicable;
1155 bool RValueRef = DestReference->isRValueReferenceType();
1156 if (!RValueRef && !SrcExpr->isLValue()) {
1157 // We know the left side is an lvalue reference, so we can suggest a reason.
1158 msg = diag::err_bad_cxx_cast_rvalue;
1159 return TC_NotApplicable;
1162 QualType DestPointee = DestReference->getPointeeType();
1164 // FIXME: If the source is a prvalue, we should issue a warning (because the
1165 // cast always has undefined behavior), and for AST consistency, we should
1166 // materialize a temporary.
1167 return TryStaticDowncast(Self,
1168 Self.Context.getCanonicalType(SrcExpr->getType()),
1169 Self.Context.getCanonicalType(DestPointee), CStyle,
1170 OpRange, SrcExpr->getType(), DestType, msg, Kind,
1174 /// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1176 TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
1177 bool CStyle, const SourceRange &OpRange,
1178 unsigned &msg, CastKind &Kind,
1179 CXXCastPath &BasePath) {
1180 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1181 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1182 // is a class derived from B, if a valid standard conversion from "pointer
1183 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1185 // In addition, DR54 clarifies that the base must be accessible in the
1188 const PointerType *DestPointer = DestType->getAs<PointerType>();
1190 return TC_NotApplicable;
1193 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1195 msg = diag::err_bad_static_cast_pointer_nonpointer;
1196 return TC_NotApplicable;
1199 return TryStaticDowncast(Self,
1200 Self.Context.getCanonicalType(SrcPointer->getPointeeType()),
1201 Self.Context.getCanonicalType(DestPointer->getPointeeType()),
1202 CStyle, OpRange, SrcType, DestType, msg, Kind,
1206 /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1207 /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1208 /// DestType is possible and allowed.
1210 TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType,
1211 bool CStyle, const SourceRange &OpRange, QualType OrigSrcType,
1212 QualType OrigDestType, unsigned &msg,
1213 CastKind &Kind, CXXCastPath &BasePath) {
1214 // We can only work with complete types. But don't complain if it doesn't work
1215 if (Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0) ||
1216 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0))
1217 return TC_NotApplicable;
1219 // Downcast can only happen in class hierarchies, so we need classes.
1220 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1221 return TC_NotApplicable;
1224 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1225 /*DetectVirtual=*/true);
1226 if (!Self.IsDerivedFrom(DestType, SrcType, Paths)) {
1227 return TC_NotApplicable;
1230 // Target type does derive from source type. Now we're serious. If an error
1231 // appears now, it's not ignored.
1232 // This may not be entirely in line with the standard. Take for example:
1234 // struct B : virtual A {
1240 // (void)static_cast<const B&>(*((A*)0));
1242 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1243 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1244 // However, both GCC and Comeau reject this example, and accepting it would
1245 // mean more complex code if we're to preserve the nice error message.
1246 // FIXME: Being 100% compliant here would be nice to have.
1248 // Must preserve cv, as always, unless we're in C-style mode.
1249 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) {
1250 msg = diag::err_bad_cxx_cast_qualifiers_away;
1254 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
1255 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1256 // that it builds the paths in reverse order.
1257 // To sum up: record all paths to the base and build a nice string from
1258 // them. Use it to spice up the error message.
1259 if (!Paths.isRecordingPaths()) {
1261 Paths.setRecordingPaths(true);
1262 Self.IsDerivedFrom(DestType, SrcType, Paths);
1264 std::string PathDisplayStr;
1265 std::set<unsigned> DisplayedPaths;
1266 for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end();
1268 if (DisplayedPaths.insert(PI->back().SubobjectNumber).second) {
1269 // We haven't displayed a path to this particular base
1270 // class subobject yet.
1271 PathDisplayStr += "\n ";
1272 for (CXXBasePath::const_reverse_iterator EI = PI->rbegin(),
1275 PathDisplayStr += EI->Base->getType().getAsString() + " -> ";
1276 PathDisplayStr += QualType(DestType).getAsString();
1280 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
1281 << QualType(SrcType).getUnqualifiedType()
1282 << QualType(DestType).getUnqualifiedType()
1283 << PathDisplayStr << OpRange;
1288 if (Paths.getDetectedVirtual() != nullptr) {
1289 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1290 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
1291 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1297 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1300 diag::err_downcast_from_inaccessible_base)) {
1301 case Sema::AR_accessible:
1302 case Sema::AR_delayed: // be optimistic
1303 case Sema::AR_dependent: // be optimistic
1306 case Sema::AR_inaccessible:
1312 Self.BuildBasePathArray(Paths, BasePath);
1313 Kind = CK_BaseToDerived;
1317 /// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1318 /// C++ 5.2.9p9 is valid:
1320 /// An rvalue of type "pointer to member of D of type cv1 T" can be
1321 /// converted to an rvalue of type "pointer to member of B of type cv2 T",
1322 /// where B is a base class of D [...].
1325 TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
1326 QualType DestType, bool CStyle,
1327 const SourceRange &OpRange,
1328 unsigned &msg, CastKind &Kind,
1329 CXXCastPath &BasePath) {
1330 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1332 return TC_NotApplicable;
1334 bool WasOverloadedFunction = false;
1335 DeclAccessPair FoundOverload;
1336 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1337 if (FunctionDecl *Fn
1338 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false,
1340 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
1341 SrcType = Self.Context.getMemberPointerType(Fn->getType(),
1342 Self.Context.getTypeDeclType(M->getParent()).getTypePtr());
1343 WasOverloadedFunction = true;
1347 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1349 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1350 return TC_NotApplicable;
1353 // T == T, modulo cv
1354 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(),
1355 DestMemPtr->getPointeeType()))
1356 return TC_NotApplicable;
1359 QualType SrcClass(SrcMemPtr->getClass(), 0);
1360 QualType DestClass(DestMemPtr->getClass(), 0);
1361 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1362 /*DetectVirtual=*/true);
1363 if (Self.RequireCompleteType(OpRange.getBegin(), SrcClass, 0) ||
1364 !Self.IsDerivedFrom(SrcClass, DestClass, Paths)) {
1365 return TC_NotApplicable;
1368 // B is a base of D. But is it an allowed base? If not, it's a hard error.
1369 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) {
1371 Paths.setRecordingPaths(true);
1372 bool StillOkay = Self.IsDerivedFrom(SrcClass, DestClass, Paths);
1375 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths);
1376 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv)
1377 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange;
1382 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
1383 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
1384 << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
1390 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1391 DestClass, SrcClass,
1393 diag::err_upcast_to_inaccessible_base)) {
1394 case Sema::AR_accessible:
1395 case Sema::AR_delayed:
1396 case Sema::AR_dependent:
1397 // Optimistically assume that the delayed and dependent cases
1401 case Sema::AR_inaccessible:
1407 if (WasOverloadedFunction) {
1408 // Resolve the address of the overloaded function again, this time
1409 // allowing complaints if something goes wrong.
1410 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
1419 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn);
1420 if (!SrcExpr.isUsable()) {
1426 Self.BuildBasePathArray(Paths, BasePath);
1427 Kind = CK_DerivedToBaseMemberPointer;
1431 /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1434 /// An expression e can be explicitly converted to a type T using a
1435 /// @c static_cast if the declaration "T t(e);" is well-formed [...].
1437 TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType,
1438 Sema::CheckedConversionKind CCK,
1439 const SourceRange &OpRange, unsigned &msg,
1440 CastKind &Kind, bool ListInitialization) {
1441 if (DestType->isRecordType()) {
1442 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1443 diag::err_bad_dynamic_cast_incomplete) ||
1444 Self.RequireNonAbstractType(OpRange.getBegin(), DestType,
1445 diag::err_allocation_of_abstract_type)) {
1449 } else if (DestType->isMemberPointerType()) {
1450 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1451 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0);
1455 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType);
1456 InitializationKind InitKind
1457 = (CCK == Sema::CCK_CStyleCast)
1458 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange,
1460 : (CCK == Sema::CCK_FunctionalCast)
1461 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization)
1462 : InitializationKind::CreateCast(OpRange);
1463 Expr *SrcExprRaw = SrcExpr.get();
1464 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1466 // At this point of CheckStaticCast, if the destination is a reference,
1467 // or the expression is an overload expression this has to work.
1468 // There is no other way that works.
1469 // On the other hand, if we're checking a C-style cast, we've still got
1470 // the reinterpret_cast way.
1472 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1473 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1474 return TC_NotApplicable;
1476 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw);
1477 if (Result.isInvalid()) {
1482 if (InitSeq.isConstructorInitialization())
1483 Kind = CK_ConstructorConversion;
1491 /// TryConstCast - See if a const_cast from source to destination is allowed,
1492 /// and perform it if it is.
1493 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1494 QualType DestType, bool CStyle,
1496 DestType = Self.Context.getCanonicalType(DestType);
1497 QualType SrcType = SrcExpr.get()->getType();
1498 bool NeedToMaterializeTemporary = false;
1500 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1502 // if a pointer to T1 can be explicitly converted to the type "pointer to
1503 // T2" using a const_cast, then the following conversions can also be
1505 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1506 // type T2 using the cast const_cast<T2&>;
1507 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1508 // type T2 using the cast const_cast<T2&&>; and
1509 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1510 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1512 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1513 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1514 // is C-style, static_cast might find a way, so we simply suggest a
1515 // message and tell the parent to keep searching.
1516 msg = diag::err_bad_cxx_cast_rvalue;
1517 return TC_NotApplicable;
1520 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) {
1521 if (!SrcType->isRecordType()) {
1522 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1523 // this is C-style, static_cast can do this.
1524 msg = diag::err_bad_cxx_cast_rvalue;
1525 return TC_NotApplicable;
1528 // Materialize the class prvalue so that the const_cast can bind a
1530 NeedToMaterializeTemporary = true;
1533 // It's not completely clear under the standard whether we can
1534 // const_cast bit-field gl-values. Doing so would not be
1535 // intrinsically complicated, but for now, we say no for
1536 // consistency with other compilers and await the word of the
1538 if (SrcExpr.get()->refersToBitField()) {
1539 msg = diag::err_bad_cxx_cast_bitfield;
1540 return TC_NotApplicable;
1543 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1544 SrcType = Self.Context.getPointerType(SrcType);
1547 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
1548 // the rules for const_cast are the same as those used for pointers.
1550 if (!DestType->isPointerType() &&
1551 !DestType->isMemberPointerType() &&
1552 !DestType->isObjCObjectPointerType()) {
1553 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
1554 // was a reference type, we converted it to a pointer above.
1555 // The status of rvalue references isn't entirely clear, but it looks like
1556 // conversion to them is simply invalid.
1557 // C++ 5.2.11p3: For two pointer types [...]
1559 msg = diag::err_bad_const_cast_dest;
1560 return TC_NotApplicable;
1562 if (DestType->isFunctionPointerType() ||
1563 DestType->isMemberFunctionPointerType()) {
1564 // Cannot cast direct function pointers.
1565 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
1566 // T is the ultimate pointee of source and target type.
1568 msg = diag::err_bad_const_cast_dest;
1569 return TC_NotApplicable;
1571 SrcType = Self.Context.getCanonicalType(SrcType);
1573 // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are
1574 // completely equal.
1575 // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers
1576 // in multi-level pointers may change, but the level count must be the same,
1577 // as must be the final pointee type.
1578 while (SrcType != DestType &&
1579 Self.Context.UnwrapSimilarPointerTypes(SrcType, DestType)) {
1580 Qualifiers SrcQuals, DestQuals;
1581 SrcType = Self.Context.getUnqualifiedArrayType(SrcType, SrcQuals);
1582 DestType = Self.Context.getUnqualifiedArrayType(DestType, DestQuals);
1584 // const_cast is permitted to strip cvr-qualifiers, only. Make sure that
1585 // the other qualifiers (e.g., address spaces) are identical.
1586 SrcQuals.removeCVRQualifiers();
1587 DestQuals.removeCVRQualifiers();
1588 if (SrcQuals != DestQuals)
1589 return TC_NotApplicable;
1592 // Since we're dealing in canonical types, the remainder must be the same.
1593 if (SrcType != DestType)
1594 return TC_NotApplicable;
1596 if (NeedToMaterializeTemporary)
1597 // This is a const_cast from a class prvalue to an rvalue reference type.
1598 // Materialize a temporary to store the result of the conversion.
1599 SrcExpr = new (Self.Context) MaterializeTemporaryExpr(
1600 SrcType, SrcExpr.get(), /*IsLValueReference*/ false);
1605 // Checks for undefined behavior in reinterpret_cast.
1606 // The cases that is checked for is:
1607 // *reinterpret_cast<T*>(&a)
1608 // reinterpret_cast<T&>(a)
1609 // where accessing 'a' as type 'T' will result in undefined behavior.
1610 void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
1612 SourceRange Range) {
1613 unsigned DiagID = IsDereference ?
1614 diag::warn_pointer_indirection_from_incompatible_type :
1615 diag::warn_undefined_reinterpret_cast;
1617 if (Diags.isIgnored(DiagID, Range.getBegin()))
1620 QualType SrcTy, DestTy;
1621 if (IsDereference) {
1622 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
1625 SrcTy = SrcType->getPointeeType();
1626 DestTy = DestType->getPointeeType();
1628 if (!DestType->getAs<ReferenceType>()) {
1632 DestTy = DestType->getPointeeType();
1635 // Cast is compatible if the types are the same.
1636 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) {
1639 // or one of the types is a char or void type
1640 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
1641 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
1644 // or one of the types is a tag type.
1645 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
1649 // FIXME: Scoped enums?
1650 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
1651 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
1652 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) {
1657 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range;
1660 static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
1661 QualType DestType) {
1662 QualType SrcType = SrcExpr.get()->getType();
1663 if (Self.Context.hasSameType(SrcType, DestType))
1665 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
1666 if (SrcPtrTy->isObjCSelType()) {
1667 QualType DT = DestType;
1668 if (isa<PointerType>(DestType))
1669 DT = DestType->getPointeeType();
1670 if (!DT.getUnqualifiedType()->isVoidType())
1671 Self.Diag(SrcExpr.get()->getExprLoc(),
1672 diag::warn_cast_pointer_from_sel)
1673 << SrcType << DestType << SrcExpr.get()->getSourceRange();
1677 static void checkIntToPointerCast(bool CStyle, SourceLocation Loc,
1678 const Expr *SrcExpr, QualType DestType,
1680 QualType SrcType = SrcExpr->getType();
1682 // Not warning on reinterpret_cast, boolean, constant expressions, etc
1683 // are not explicit design choices, but consistent with GCC's behavior.
1684 // Feel free to modify them if you've reason/evidence for an alternative.
1685 if (CStyle && SrcType->isIntegralType(Self.Context)
1686 && !SrcType->isBooleanType()
1687 && !SrcType->isEnumeralType()
1688 && !SrcExpr->isIntegerConstantExpr(Self.Context)
1689 && Self.Context.getTypeSize(DestType) >
1690 Self.Context.getTypeSize(SrcType)) {
1691 // Separate between casts to void* and non-void* pointers.
1692 // Some APIs use (abuse) void* for something like a user context,
1693 // and often that value is an integer even if it isn't a pointer itself.
1694 // Having a separate warning flag allows users to control the warning
1695 // for their workflow.
1696 unsigned Diag = DestType->isVoidPointerType() ?
1697 diag::warn_int_to_void_pointer_cast
1698 : diag::warn_int_to_pointer_cast;
1699 Self.Diag(Loc, Diag) << SrcType << DestType;
1703 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
1704 QualType DestType, bool CStyle,
1705 const SourceRange &OpRange,
1708 bool IsLValueCast = false;
1710 DestType = Self.Context.getCanonicalType(DestType);
1711 QualType SrcType = SrcExpr.get()->getType();
1713 // Is the source an overloaded name? (i.e. &foo)
1714 // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5) ...
1715 if (SrcType == Self.Context.OverloadTy) {
1716 // ... unless foo<int> resolves to an lvalue unambiguously.
1717 // TODO: what if this fails because of DiagnoseUseOfDecl or something
1719 ExprResult SingleFunctionExpr = SrcExpr;
1720 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
1722 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
1723 ) && SingleFunctionExpr.isUsable()) {
1724 SrcExpr = SingleFunctionExpr;
1725 SrcType = SrcExpr.get()->getType();
1727 return TC_NotApplicable;
1731 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
1732 if (!SrcExpr.get()->isGLValue()) {
1733 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
1734 // similar comment in const_cast.
1735 msg = diag::err_bad_cxx_cast_rvalue;
1736 return TC_NotApplicable;
1740 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
1741 /*isDereference=*/false, OpRange);
1744 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
1745 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
1746 // built-in & and * operators.
1748 const char *inappropriate = nullptr;
1749 switch (SrcExpr.get()->getObjectKind()) {
1752 case OK_BitField: inappropriate = "bit-field"; break;
1753 case OK_VectorComponent: inappropriate = "vector element"; break;
1754 case OK_ObjCProperty: inappropriate = "property expression"; break;
1755 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
1758 if (inappropriate) {
1759 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference)
1760 << inappropriate << DestType
1761 << OpRange << SrcExpr.get()->getSourceRange();
1762 msg = 0; SrcExpr = ExprError();
1763 return TC_NotApplicable;
1766 // This code does this transformation for the checked types.
1767 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1768 SrcType = Self.Context.getPointerType(SrcType);
1770 IsLValueCast = true;
1773 // Canonicalize source for comparison.
1774 SrcType = Self.Context.getCanonicalType(SrcType);
1776 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
1777 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1778 if (DestMemPtr && SrcMemPtr) {
1779 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
1780 // can be explicitly converted to an rvalue of type "pointer to member
1781 // of Y of type T2" if T1 and T2 are both function types or both object
1783 if (DestMemPtr->getPointeeType()->isFunctionType() !=
1784 SrcMemPtr->getPointeeType()->isFunctionType())
1785 return TC_NotApplicable;
1787 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
1789 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
1791 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
1792 /*CheckObjCLifetime=*/CStyle)) {
1793 msg = diag::err_bad_cxx_cast_qualifiers_away;
1797 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1798 // We need to determine the inheritance model that the class will use if
1800 Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0);
1801 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0);
1804 // Don't allow casting between member pointers of different sizes.
1805 if (Self.Context.getTypeSize(DestMemPtr) !=
1806 Self.Context.getTypeSize(SrcMemPtr)) {
1807 msg = diag::err_bad_cxx_cast_member_pointer_size;
1811 // A valid member pointer cast.
1812 assert(!IsLValueCast);
1813 Kind = CK_ReinterpretMemberPointer;
1817 // See below for the enumeral issue.
1818 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) {
1819 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
1820 // type large enough to hold it. A value of std::nullptr_t can be
1821 // converted to an integral type; the conversion has the same meaning
1822 // and validity as a conversion of (void*)0 to the integral type.
1823 if (Self.Context.getTypeSize(SrcType) >
1824 Self.Context.getTypeSize(DestType)) {
1825 msg = diag::err_bad_reinterpret_cast_small_int;
1828 Kind = CK_PointerToIntegral;
1832 bool destIsVector = DestType->isVectorType();
1833 bool srcIsVector = SrcType->isVectorType();
1834 if (srcIsVector || destIsVector) {
1835 // FIXME: Should this also apply to floating point types?
1836 bool srcIsScalar = SrcType->isIntegralType(Self.Context);
1837 bool destIsScalar = DestType->isIntegralType(Self.Context);
1839 // Check if this is a cast between a vector and something else.
1840 if (!(srcIsScalar && destIsVector) && !(srcIsVector && destIsScalar) &&
1841 !(srcIsVector && destIsVector))
1842 return TC_NotApplicable;
1844 // If both types have the same size, we can successfully cast.
1845 if (Self.Context.getTypeSize(SrcType)
1846 == Self.Context.getTypeSize(DestType)) {
1852 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
1853 else if (srcIsScalar)
1854 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
1856 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
1861 if (SrcType == DestType) {
1862 // C++ 5.2.10p2 has a note that mentions that, subject to all other
1863 // restrictions, a cast to the same type is allowed so long as it does not
1864 // cast away constness. In C++98, the intent was not entirely clear here,
1865 // since all other paragraphs explicitly forbid casts to the same type.
1866 // C++11 clarifies this case with p2.
1868 // The only allowed types are: integral, enumeration, pointer, or
1869 // pointer-to-member types. We also won't restrict Obj-C pointers either.
1871 TryCastResult Result = TC_NotApplicable;
1872 if (SrcType->isIntegralOrEnumerationType() ||
1873 SrcType->isAnyPointerType() ||
1874 SrcType->isMemberPointerType() ||
1875 SrcType->isBlockPointerType()) {
1876 Result = TC_Success;
1881 bool destIsPtr = DestType->isAnyPointerType() ||
1882 DestType->isBlockPointerType();
1883 bool srcIsPtr = SrcType->isAnyPointerType() ||
1884 SrcType->isBlockPointerType();
1885 if (!destIsPtr && !srcIsPtr) {
1886 // Except for std::nullptr_t->integer and lvalue->reference, which are
1887 // handled above, at least one of the two arguments must be a pointer.
1888 return TC_NotApplicable;
1891 if (DestType->isIntegralType(Self.Context)) {
1892 assert(srcIsPtr && "One type must be a pointer");
1893 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
1894 // type large enough to hold it; except in Microsoft mode, where the
1895 // integral type size doesn't matter (except we don't allow bool).
1896 bool MicrosoftException = Self.getLangOpts().MicrosoftExt &&
1897 !DestType->isBooleanType();
1898 if ((Self.Context.getTypeSize(SrcType) >
1899 Self.Context.getTypeSize(DestType)) &&
1900 !MicrosoftException) {
1901 msg = diag::err_bad_reinterpret_cast_small_int;
1904 Kind = CK_PointerToIntegral;
1908 if (SrcType->isIntegralOrEnumerationType()) {
1909 assert(destIsPtr && "One type must be a pointer");
1910 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType,
1912 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
1913 // converted to a pointer.
1914 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
1915 // necessarily converted to a null pointer value.]
1916 Kind = CK_IntegralToPointer;
1920 if (!destIsPtr || !srcIsPtr) {
1921 // With the valid non-pointer conversions out of the way, we can be even
1923 return TC_NotApplicable;
1926 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
1927 // The C-style cast operator can.
1928 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
1929 /*CheckObjCLifetime=*/CStyle)) {
1930 msg = diag::err_bad_cxx_cast_qualifiers_away;
1934 // Cannot convert between block pointers and Objective-C object pointers.
1935 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
1936 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
1937 return TC_NotApplicable;
1940 Kind = CK_LValueBitCast;
1941 } else if (DestType->isObjCObjectPointerType()) {
1942 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
1943 } else if (DestType->isBlockPointerType()) {
1944 if (!SrcType->isBlockPointerType()) {
1945 Kind = CK_AnyPointerToBlockPointerCast;
1953 // Any pointer can be cast to an Objective-C pointer type with a C-style
1955 if (CStyle && DestType->isObjCObjectPointerType()) {
1959 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
1961 // Not casting away constness, so the only remaining check is for compatible
1962 // pointer categories.
1964 if (SrcType->isFunctionPointerType()) {
1965 if (DestType->isFunctionPointerType()) {
1966 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
1967 // a pointer to a function of a different type.
1971 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
1972 // an object type or vice versa is conditionally-supported.
1973 // Compilers support it in C++03 too, though, because it's necessary for
1974 // casting the return value of dlsym() and GetProcAddress().
1975 // FIXME: Conditionally-supported behavior should be configurable in the
1976 // TargetInfo or similar.
1977 Self.Diag(OpRange.getBegin(),
1978 Self.getLangOpts().CPlusPlus11 ?
1979 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
1984 if (DestType->isFunctionPointerType()) {
1986 Self.Diag(OpRange.getBegin(),
1987 Self.getLangOpts().CPlusPlus11 ?
1988 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
1993 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
1994 // a pointer to an object of different type.
1995 // Void pointers are not specified, but supported by every compiler out there.
1996 // So we finish by allowing everything that remains - it's got to be two
2001 void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2002 bool ListInitialization) {
2003 // Handle placeholders.
2004 if (isPlaceholder()) {
2005 // C-style casts can resolve __unknown_any types.
2006 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2007 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2008 SrcExpr.get(), Kind,
2009 ValueKind, BasePath);
2013 checkNonOverloadPlaceholders();
2014 if (SrcExpr.isInvalid())
2018 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2019 // This test is outside everything else because it's the only case where
2020 // a non-lvalue-reference target type does not lead to decay.
2021 if (DestType->isVoidType()) {
2024 if (claimPlaceholder(BuiltinType::Overload)) {
2025 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2026 SrcExpr, /* Decay Function to ptr */ false,
2027 /* Complain */ true, DestRange, DestType,
2028 diag::err_bad_cstyle_cast_overload);
2029 if (SrcExpr.isInvalid())
2033 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2037 // If the type is dependent, we won't do any other semantic analysis now.
2038 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2039 SrcExpr.get()->isValueDependent()) {
2040 assert(Kind == CK_Dependent);
2044 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
2045 !isPlaceholder(BuiltinType::Overload)) {
2046 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2047 if (SrcExpr.isInvalid())
2051 // AltiVec vector initialization with a single literal.
2052 if (const VectorType *vecTy = DestType->getAs<VectorType>())
2053 if (vecTy->getVectorKind() == VectorType::AltiVecVector
2054 && (SrcExpr.get()->getType()->isIntegerType()
2055 || SrcExpr.get()->getType()->isFloatingType())) {
2056 Kind = CK_VectorSplat;
2060 // C++ [expr.cast]p5: The conversions performed by
2063 // - a static_cast followed by a const_cast,
2064 // - a reinterpret_cast, or
2065 // - a reinterpret_cast followed by a const_cast,
2066 // can be performed using the cast notation of explicit type conversion.
2067 // [...] If a conversion can be interpreted in more than one of the ways
2068 // listed above, the interpretation that appears first in the list is used,
2069 // even if a cast resulting from that interpretation is ill-formed.
2070 // In plain language, this means trying a const_cast ...
2071 unsigned msg = diag::err_bad_cxx_cast_generic;
2072 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2073 /*CStyle*/true, msg);
2074 if (SrcExpr.isInvalid())
2076 if (tcr == TC_Success)
2079 Sema::CheckedConversionKind CCK
2080 = FunctionalStyle? Sema::CCK_FunctionalCast
2081 : Sema::CCK_CStyleCast;
2082 if (tcr == TC_NotApplicable) {
2083 // ... or if that is not possible, a static_cast, ignoring const, ...
2084 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange,
2085 msg, Kind, BasePath, ListInitialization);
2086 if (SrcExpr.isInvalid())
2089 if (tcr == TC_NotApplicable) {
2090 // ... and finally a reinterpret_cast, ignoring const.
2091 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true,
2092 OpRange, msg, Kind);
2093 if (SrcExpr.isInvalid())
2098 if (Self.getLangOpts().ObjCAutoRefCount && tcr == TC_Success)
2099 checkObjCARCConversion(CCK);
2101 if (tcr != TC_Success && msg != 0) {
2102 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2103 DeclAccessPair Found;
2104 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
2109 // If DestType is a function type (not to be confused with the function
2110 // pointer type), it will be possible to resolve the function address,
2111 // but the type cast should be considered as failure.
2112 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression;
2113 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload)
2114 << OE->getName() << DestType << OpRange
2115 << OE->getQualifierLoc().getSourceRange();
2116 Self.NoteAllOverloadCandidates(SrcExpr.get());
2119 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle),
2120 OpRange, SrcExpr.get(), DestType, ListInitialization);
2122 } else if (Kind == CK_BitCast) {
2126 // Clear out SrcExpr if there was a fatal error.
2127 if (tcr != TC_Success)
2128 SrcExpr = ExprError();
2131 /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2132 /// non-matching type. Such as enum function call to int, int call to
2133 /// pointer; etc. Cast to 'void' is an exception.
2134 static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2135 QualType DestType) {
2136 if (Self.Diags.isIgnored(diag::warn_bad_function_cast,
2137 SrcExpr.get()->getExprLoc()))
2140 if (!isa<CallExpr>(SrcExpr.get()))
2143 QualType SrcType = SrcExpr.get()->getType();
2144 if (DestType.getUnqualifiedType()->isVoidType())
2146 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2147 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2149 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2150 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2151 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2153 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2155 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2157 if (SrcType->isComplexType() && DestType->isComplexType())
2159 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2162 Self.Diag(SrcExpr.get()->getExprLoc(),
2163 diag::warn_bad_function_cast)
2164 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2167 /// Check the semantics of a C-style cast operation, in C.
2168 void CastOperation::CheckCStyleCast() {
2169 assert(!Self.getLangOpts().CPlusPlus);
2171 // C-style casts can resolve __unknown_any types.
2172 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2173 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2174 SrcExpr.get(), Kind,
2175 ValueKind, BasePath);
2179 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
2180 // type needs to be scalar.
2181 if (DestType->isVoidType()) {
2182 // We don't necessarily do lvalue-to-rvalue conversions on this.
2183 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2184 if (SrcExpr.isInvalid())
2187 // Cast to void allows any expr type.
2192 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2193 if (SrcExpr.isInvalid())
2195 QualType SrcType = SrcExpr.get()->getType();
2197 assert(!SrcType->isPlaceholderType());
2199 // OpenCL v1 s6.5: Casting a pointer to address space A to a pointer to
2200 // address space B is illegal.
2201 if (Self.getLangOpts().OpenCL && DestType->isPointerType() &&
2202 SrcType->isPointerType()) {
2203 if (DestType->getPointeeType().getAddressSpace() !=
2204 SrcType->getPointeeType().getAddressSpace()) {
2205 Self.Diag(OpRange.getBegin(),
2206 diag::err_typecheck_incompatible_address_space)
2207 << SrcType << DestType << Sema::AA_Casting
2208 << SrcExpr.get()->getSourceRange();
2209 SrcExpr = ExprError();
2214 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2215 diag::err_typecheck_cast_to_incomplete)) {
2216 SrcExpr = ExprError();
2220 if (!DestType->isScalarType() && !DestType->isVectorType()) {
2221 const RecordType *DestRecordTy = DestType->getAs<RecordType>();
2223 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){
2224 // GCC struct/union extension: allow cast to self.
2225 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar)
2226 << DestType << SrcExpr.get()->getSourceRange();
2231 // GCC's cast to union extension.
2232 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) {
2233 RecordDecl *RD = DestRecordTy->getDecl();
2234 RecordDecl::field_iterator Field, FieldEnd;
2235 for (Field = RD->field_begin(), FieldEnd = RD->field_end();
2236 Field != FieldEnd; ++Field) {
2237 if (Self.Context.hasSameUnqualifiedType(Field->getType(), SrcType) &&
2238 !Field->isUnnamedBitfield()) {
2239 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union)
2240 << SrcExpr.get()->getSourceRange();
2244 if (Field == FieldEnd) {
2245 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type)
2246 << SrcType << SrcExpr.get()->getSourceRange();
2247 SrcExpr = ExprError();
2254 // Reject any other conversions to non-scalar types.
2255 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar)
2256 << DestType << SrcExpr.get()->getSourceRange();
2257 SrcExpr = ExprError();
2261 // The type we're casting to is known to be a scalar or vector.
2263 // Require the operand to be a scalar or vector.
2264 if (!SrcType->isScalarType() && !SrcType->isVectorType()) {
2265 Self.Diag(SrcExpr.get()->getExprLoc(),
2266 diag::err_typecheck_expect_scalar_operand)
2267 << SrcType << SrcExpr.get()->getSourceRange();
2268 SrcExpr = ExprError();
2272 if (DestType->isExtVectorType()) {
2273 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind);
2277 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
2278 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector &&
2279 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
2280 Kind = CK_VectorSplat;
2281 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) {
2282 SrcExpr = ExprError();
2287 if (SrcType->isVectorType()) {
2288 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind))
2289 SrcExpr = ExprError();
2293 // The source and target types are both scalars, i.e.
2294 // - arithmetic types (fundamental, enum, and complex)
2295 // - all kinds of pointers
2296 // Note that member pointers were filtered out with C++, above.
2298 if (isa<ObjCSelectorExpr>(SrcExpr.get())) {
2299 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr);
2300 SrcExpr = ExprError();
2304 // If either type is a pointer, the other type has to be either an
2305 // integer or a pointer.
2306 if (!DestType->isArithmeticType()) {
2307 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) {
2308 Self.Diag(SrcExpr.get()->getExprLoc(),
2309 diag::err_cast_pointer_from_non_pointer_int)
2310 << SrcType << SrcExpr.get()->getSourceRange();
2311 SrcExpr = ExprError();
2314 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(),
2316 } else if (!SrcType->isArithmeticType()) {
2317 if (!DestType->isIntegralType(Self.Context) &&
2318 DestType->isArithmeticType()) {
2319 Self.Diag(SrcExpr.get()->getLocStart(),
2320 diag::err_cast_pointer_to_non_pointer_int)
2321 << DestType << SrcExpr.get()->getSourceRange();
2322 SrcExpr = ExprError();
2327 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().cl_khr_fp16) {
2328 if (DestType->isHalfType()) {
2329 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half)
2330 << DestType << SrcExpr.get()->getSourceRange();
2331 SrcExpr = ExprError();
2336 // ARC imposes extra restrictions on casts.
2337 if (Self.getLangOpts().ObjCAutoRefCount) {
2338 checkObjCARCConversion(Sema::CCK_CStyleCast);
2339 if (SrcExpr.isInvalid())
2342 if (const PointerType *CastPtr = DestType->getAs<PointerType>()) {
2343 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
2344 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
2345 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
2346 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
2347 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
2348 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) {
2349 Self.Diag(SrcExpr.get()->getLocStart(),
2350 diag::err_typecheck_incompatible_ownership)
2351 << SrcType << DestType << Sema::AA_Casting
2352 << SrcExpr.get()->getSourceRange();
2357 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) {
2358 Self.Diag(SrcExpr.get()->getLocStart(),
2359 diag::err_arc_convesion_of_weak_unavailable)
2360 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2361 SrcExpr = ExprError();
2366 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2367 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
2368 Kind = Self.PrepareScalarCast(SrcExpr, DestType);
2369 if (SrcExpr.isInvalid())
2372 if (Kind == CK_BitCast)
2376 ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
2377 TypeSourceInfo *CastTypeInfo,
2378 SourceLocation RPLoc,
2380 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
2381 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2382 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd());
2384 if (getLangOpts().CPlusPlus) {
2385 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false,
2386 isa<InitListExpr>(CastExpr));
2388 Op.CheckCStyleCast();
2391 if (Op.SrcExpr.isInvalid())
2394 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType,
2395 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
2396 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc));
2399 ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
2400 SourceLocation LPLoc,
2402 SourceLocation RPLoc) {
2403 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
2404 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
2405 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2406 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd());
2408 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false);
2409 if (Op.SrcExpr.isInvalid())
2412 if (CXXConstructExpr *ConstructExpr = dyn_cast<CXXConstructExpr>(Op.SrcExpr.get()))
2413 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc));
2415 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType,
2416 Op.ValueKind, CastTypeInfo, Op.Kind,
2417 Op.SrcExpr.get(), &Op.BasePath, LPLoc, RPLoc));