1 //===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements semantic analysis for cast expressions, including
10 // 1) C-style casts like '(int) x'
11 // 2) C++ functional casts like 'int(x)'
12 // 3) C++ named casts like 'static_cast<int>(x)'
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/ASTStructuralEquivalence.h"
18 #include "clang/AST/CXXInheritance.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ExprObjC.h"
21 #include "clang/AST/RecordLayout.h"
22 #include "clang/Basic/PartialDiagnostic.h"
23 #include "clang/Basic/TargetInfo.h"
24 #include "clang/Lex/Preprocessor.h"
25 #include "clang/Sema/Initialization.h"
26 #include "clang/Sema/SemaInternal.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include <set>
29 using namespace clang;
30
31
32
33 enum TryCastResult {
34 TC_NotApplicable, ///< The cast method is not applicable.
35 TC_Success, ///< The cast method is appropriate and successful.
36 TC_Extension, ///< The cast method is appropriate and accepted as a
37 ///< language extension.
38 TC_Failed ///< The cast method is appropriate, but failed. A
39 ///< diagnostic has been emitted.
40 };
41
isValidCast(TryCastResult TCR)42 static bool isValidCast(TryCastResult TCR) {
43 return TCR == TC_Success || TCR == TC_Extension;
44 }
45
46 enum CastType {
47 CT_Const, ///< const_cast
48 CT_Static, ///< static_cast
49 CT_Reinterpret, ///< reinterpret_cast
50 CT_Dynamic, ///< dynamic_cast
51 CT_CStyle, ///< (Type)expr
52 CT_Functional, ///< Type(expr)
53 CT_Addrspace ///< addrspace_cast
54 };
55
56 namespace {
57 struct CastOperation {
CastOperation__anon12e0d18e0111::CastOperation58 CastOperation(Sema &S, QualType destType, ExprResult src)
59 : Self(S), SrcExpr(src), DestType(destType),
60 ResultType(destType.getNonLValueExprType(S.Context)),
61 ValueKind(Expr::getValueKindForType(destType)),
62 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
63
64 // C++ [expr.type]/8.2.2:
65 // If a pr-value initially has the type cv-T, where T is a
66 // cv-unqualified non-class, non-array type, the type of the
67 // expression is adjusted to T prior to any further analysis.
68 if (!S.Context.getLangOpts().ObjC && !DestType->isRecordType() &&
69 !DestType->isArrayType()) {
70 DestType = DestType.getUnqualifiedType();
71 }
72
73 if (const BuiltinType *placeholder =
74 src.get()->getType()->getAsPlaceholderType()) {
75 PlaceholderKind = placeholder->getKind();
76 } else {
77 PlaceholderKind = (BuiltinType::Kind) 0;
78 }
79 }
80
81 Sema &Self;
82 ExprResult SrcExpr;
83 QualType DestType;
84 QualType ResultType;
85 ExprValueKind ValueKind;
86 CastKind Kind;
87 BuiltinType::Kind PlaceholderKind;
88 CXXCastPath BasePath;
89 bool IsARCUnbridgedCast;
90
91 SourceRange OpRange;
92 SourceRange DestRange;
93
94 // Top-level semantics-checking routines.
95 void CheckConstCast();
96 void CheckReinterpretCast();
97 void CheckStaticCast();
98 void CheckDynamicCast();
99 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
100 void CheckCStyleCast();
101 void CheckBuiltinBitCast();
102 void CheckAddrspaceCast();
103
updatePartOfExplicitCastFlags__anon12e0d18e0111::CastOperation104 void updatePartOfExplicitCastFlags(CastExpr *CE) {
105 // Walk down from the CE to the OrigSrcExpr, and mark all immediate
106 // ImplicitCastExpr's as being part of ExplicitCastExpr. The original CE
107 // (which is a ExplicitCastExpr), and the OrigSrcExpr are not touched.
108 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(CE->getSubExpr()); CE = ICE)
109 ICE->setIsPartOfExplicitCast(true);
110 }
111
112 /// Complete an apparently-successful cast operation that yields
113 /// the given expression.
complete__anon12e0d18e0111::CastOperation114 ExprResult complete(CastExpr *castExpr) {
115 // If this is an unbridged cast, wrap the result in an implicit
116 // cast that yields the unbridged-cast placeholder type.
117 if (IsARCUnbridgedCast) {
118 castExpr = ImplicitCastExpr::Create(
119 Self.Context, Self.Context.ARCUnbridgedCastTy, CK_Dependent,
120 castExpr, nullptr, castExpr->getValueKind(),
121 Self.CurFPFeatureOverrides());
122 }
123 updatePartOfExplicitCastFlags(castExpr);
124 return castExpr;
125 }
126
127 // Internal convenience methods.
128
129 /// Try to handle the given placeholder expression kind. Return
130 /// true if the source expression has the appropriate placeholder
131 /// kind. A placeholder can only be claimed once.
claimPlaceholder__anon12e0d18e0111::CastOperation132 bool claimPlaceholder(BuiltinType::Kind K) {
133 if (PlaceholderKind != K) return false;
134
135 PlaceholderKind = (BuiltinType::Kind) 0;
136 return true;
137 }
138
isPlaceholder__anon12e0d18e0111::CastOperation139 bool isPlaceholder() const {
140 return PlaceholderKind != 0;
141 }
isPlaceholder__anon12e0d18e0111::CastOperation142 bool isPlaceholder(BuiltinType::Kind K) const {
143 return PlaceholderKind == K;
144 }
145
146 // Language specific cast restrictions for address spaces.
147 void checkAddressSpaceCast(QualType SrcType, QualType DestType);
148
checkCastAlign__anon12e0d18e0111::CastOperation149 void checkCastAlign() {
150 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
151 }
152
checkObjCConversion__anon12e0d18e0111::CastOperation153 void checkObjCConversion(Sema::CheckedConversionKind CCK) {
154 assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
155
156 Expr *src = SrcExpr.get();
157 if (Self.CheckObjCConversion(OpRange, DestType, src, CCK) ==
158 Sema::ACR_unbridged)
159 IsARCUnbridgedCast = true;
160 SrcExpr = src;
161 }
162
163 /// Check for and handle non-overload placeholder expressions.
checkNonOverloadPlaceholders__anon12e0d18e0111::CastOperation164 void checkNonOverloadPlaceholders() {
165 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload))
166 return;
167
168 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
169 if (SrcExpr.isInvalid())
170 return;
171 PlaceholderKind = (BuiltinType::Kind) 0;
172 }
173 };
174
CheckNoDeref(Sema & S,const QualType FromType,const QualType ToType,SourceLocation OpLoc)175 void CheckNoDeref(Sema &S, const QualType FromType, const QualType ToType,
176 SourceLocation OpLoc) {
177 if (const auto *PtrType = dyn_cast<PointerType>(FromType)) {
178 if (PtrType->getPointeeType()->hasAttr(attr::NoDeref)) {
179 if (const auto *DestType = dyn_cast<PointerType>(ToType)) {
180 if (!DestType->getPointeeType()->hasAttr(attr::NoDeref)) {
181 S.Diag(OpLoc, diag::warn_noderef_to_dereferenceable_pointer);
182 }
183 }
184 }
185 }
186 }
187
188 struct CheckNoDerefRAII {
CheckNoDerefRAII__anon12e0d18e0111::CheckNoDerefRAII189 CheckNoDerefRAII(CastOperation &Op) : Op(Op) {}
~CheckNoDerefRAII__anon12e0d18e0111::CheckNoDerefRAII190 ~CheckNoDerefRAII() {
191 if (!Op.SrcExpr.isInvalid())
192 CheckNoDeref(Op.Self, Op.SrcExpr.get()->getType(), Op.ResultType,
193 Op.OpRange.getBegin());
194 }
195
196 CastOperation &Op;
197 };
198 }
199
200 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
201 QualType DestType);
202
203 // The Try functions attempt a specific way of casting. If they succeed, they
204 // return TC_Success. If their way of casting is not appropriate for the given
205 // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
206 // to emit if no other way succeeds. If their way of casting is appropriate but
207 // fails, they return TC_Failed and *must* set diag; they can set it to 0 if
208 // they emit a specialized diagnostic.
209 // All diagnostics returned by these functions must expect the same three
210 // arguments:
211 // %0: Cast Type (a value from the CastType enumeration)
212 // %1: Source Type
213 // %2: Destination Type
214 static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
215 QualType DestType, bool CStyle,
216 CastKind &Kind,
217 CXXCastPath &BasePath,
218 unsigned &msg);
219 static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
220 QualType DestType, bool CStyle,
221 SourceRange OpRange,
222 unsigned &msg,
223 CastKind &Kind,
224 CXXCastPath &BasePath);
225 static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
226 QualType DestType, bool CStyle,
227 SourceRange OpRange,
228 unsigned &msg,
229 CastKind &Kind,
230 CXXCastPath &BasePath);
231 static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
232 CanQualType DestType, bool CStyle,
233 SourceRange OpRange,
234 QualType OrigSrcType,
235 QualType OrigDestType, unsigned &msg,
236 CastKind &Kind,
237 CXXCastPath &BasePath);
238 static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
239 QualType SrcType,
240 QualType DestType,bool CStyle,
241 SourceRange OpRange,
242 unsigned &msg,
243 CastKind &Kind,
244 CXXCastPath &BasePath);
245
246 static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
247 QualType DestType,
248 Sema::CheckedConversionKind CCK,
249 SourceRange OpRange,
250 unsigned &msg, CastKind &Kind,
251 bool ListInitialization);
252 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
253 QualType DestType,
254 Sema::CheckedConversionKind CCK,
255 SourceRange OpRange,
256 unsigned &msg, CastKind &Kind,
257 CXXCastPath &BasePath,
258 bool ListInitialization);
259 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
260 QualType DestType, bool CStyle,
261 unsigned &msg);
262 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
263 QualType DestType, bool CStyle,
264 SourceRange OpRange, unsigned &msg,
265 CastKind &Kind);
266 static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
267 QualType DestType, bool CStyle,
268 unsigned &msg, CastKind &Kind);
269
270 /// ActOnCXXNamedCast - Parse
271 /// {dynamic,static,reinterpret,const,addrspace}_cast's.
272 ExprResult
ActOnCXXNamedCast(SourceLocation OpLoc,tok::TokenKind Kind,SourceLocation LAngleBracketLoc,Declarator & D,SourceLocation RAngleBracketLoc,SourceLocation LParenLoc,Expr * E,SourceLocation RParenLoc)273 Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
274 SourceLocation LAngleBracketLoc, Declarator &D,
275 SourceLocation RAngleBracketLoc,
276 SourceLocation LParenLoc, Expr *E,
277 SourceLocation RParenLoc) {
278
279 assert(!D.isInvalidType());
280
281 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType());
282 if (D.isInvalidType())
283 return ExprError();
284
285 if (getLangOpts().CPlusPlus) {
286 // Check that there are no default arguments (C++ only).
287 CheckExtraCXXDefaultArguments(D);
288 }
289
290 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E,
291 SourceRange(LAngleBracketLoc, RAngleBracketLoc),
292 SourceRange(LParenLoc, RParenLoc));
293 }
294
295 ExprResult
BuildCXXNamedCast(SourceLocation OpLoc,tok::TokenKind Kind,TypeSourceInfo * DestTInfo,Expr * E,SourceRange AngleBrackets,SourceRange Parens)296 Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
297 TypeSourceInfo *DestTInfo, Expr *E,
298 SourceRange AngleBrackets, SourceRange Parens) {
299 ExprResult Ex = E;
300 QualType DestType = DestTInfo->getType();
301
302 // If the type is dependent, we won't do the semantic analysis now.
303 bool TypeDependent =
304 DestType->isDependentType() || Ex.get()->isTypeDependent();
305
306 CastOperation Op(*this, DestType, E);
307 Op.OpRange = SourceRange(OpLoc, Parens.getEnd());
308 Op.DestRange = AngleBrackets;
309
310 switch (Kind) {
311 default: llvm_unreachable("Unknown C++ cast!");
312
313 case tok::kw_addrspace_cast:
314 if (!TypeDependent) {
315 Op.CheckAddrspaceCast();
316 if (Op.SrcExpr.isInvalid())
317 return ExprError();
318 }
319 return Op.complete(CXXAddrspaceCastExpr::Create(
320 Context, Op.ResultType, Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
321 DestTInfo, OpLoc, Parens.getEnd(), AngleBrackets));
322
323 case tok::kw_const_cast:
324 if (!TypeDependent) {
325 Op.CheckConstCast();
326 if (Op.SrcExpr.isInvalid())
327 return ExprError();
328 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
329 }
330 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType,
331 Op.ValueKind, Op.SrcExpr.get(), DestTInfo,
332 OpLoc, Parens.getEnd(),
333 AngleBrackets));
334
335 case tok::kw_dynamic_cast: {
336 // dynamic_cast is not supported in C++ for OpenCL.
337 if (getLangOpts().OpenCLCPlusPlus) {
338 return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported)
339 << "dynamic_cast");
340 }
341
342 if (!TypeDependent) {
343 Op.CheckDynamicCast();
344 if (Op.SrcExpr.isInvalid())
345 return ExprError();
346 }
347 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType,
348 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
349 &Op.BasePath, DestTInfo,
350 OpLoc, Parens.getEnd(),
351 AngleBrackets));
352 }
353 case tok::kw_reinterpret_cast: {
354 if (!TypeDependent) {
355 Op.CheckReinterpretCast();
356 if (Op.SrcExpr.isInvalid())
357 return ExprError();
358 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
359 }
360 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
361 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
362 nullptr, DestTInfo, OpLoc,
363 Parens.getEnd(),
364 AngleBrackets));
365 }
366 case tok::kw_static_cast: {
367 if (!TypeDependent) {
368 Op.CheckStaticCast();
369 if (Op.SrcExpr.isInvalid())
370 return ExprError();
371 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
372 }
373
374 return Op.complete(CXXStaticCastExpr::Create(
375 Context, Op.ResultType, Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
376 &Op.BasePath, DestTInfo, CurFPFeatureOverrides(), OpLoc,
377 Parens.getEnd(), AngleBrackets));
378 }
379 }
380 }
381
ActOnBuiltinBitCastExpr(SourceLocation KWLoc,Declarator & D,ExprResult Operand,SourceLocation RParenLoc)382 ExprResult Sema::ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &D,
383 ExprResult Operand,
384 SourceLocation RParenLoc) {
385 assert(!D.isInvalidType());
386
387 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, Operand.get()->getType());
388 if (D.isInvalidType())
389 return ExprError();
390
391 return BuildBuiltinBitCastExpr(KWLoc, TInfo, Operand.get(), RParenLoc);
392 }
393
BuildBuiltinBitCastExpr(SourceLocation KWLoc,TypeSourceInfo * TSI,Expr * Operand,SourceLocation RParenLoc)394 ExprResult Sema::BuildBuiltinBitCastExpr(SourceLocation KWLoc,
395 TypeSourceInfo *TSI, Expr *Operand,
396 SourceLocation RParenLoc) {
397 CastOperation Op(*this, TSI->getType(), Operand);
398 Op.OpRange = SourceRange(KWLoc, RParenLoc);
399 TypeLoc TL = TSI->getTypeLoc();
400 Op.DestRange = SourceRange(TL.getBeginLoc(), TL.getEndLoc());
401
402 if (!Operand->isTypeDependent() && !TSI->getType()->isDependentType()) {
403 Op.CheckBuiltinBitCast();
404 if (Op.SrcExpr.isInvalid())
405 return ExprError();
406 }
407
408 BuiltinBitCastExpr *BCE =
409 new (Context) BuiltinBitCastExpr(Op.ResultType, Op.ValueKind, Op.Kind,
410 Op.SrcExpr.get(), TSI, KWLoc, RParenLoc);
411 return Op.complete(BCE);
412 }
413
414 /// Try to diagnose a failed overloaded cast. Returns true if
415 /// diagnostics were emitted.
tryDiagnoseOverloadedCast(Sema & S,CastType CT,SourceRange range,Expr * src,QualType destType,bool listInitialization)416 static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
417 SourceRange range, Expr *src,
418 QualType destType,
419 bool listInitialization) {
420 switch (CT) {
421 // These cast kinds don't consider user-defined conversions.
422 case CT_Const:
423 case CT_Reinterpret:
424 case CT_Dynamic:
425 case CT_Addrspace:
426 return false;
427
428 // These do.
429 case CT_Static:
430 case CT_CStyle:
431 case CT_Functional:
432 break;
433 }
434
435 QualType srcType = src->getType();
436 if (!destType->isRecordType() && !srcType->isRecordType())
437 return false;
438
439 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType);
440 InitializationKind initKind
441 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(),
442 range, listInitialization)
443 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range,
444 listInitialization)
445 : InitializationKind::CreateCast(/*type range?*/ range);
446 InitializationSequence sequence(S, entity, initKind, src);
447
448 assert(sequence.Failed() && "initialization succeeded on second try?");
449 switch (sequence.getFailureKind()) {
450 default: return false;
451
452 case InitializationSequence::FK_ConstructorOverloadFailed:
453 case InitializationSequence::FK_UserConversionOverloadFailed:
454 break;
455 }
456
457 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
458
459 unsigned msg = 0;
460 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
461
462 switch (sequence.getFailedOverloadResult()) {
463 case OR_Success: llvm_unreachable("successful failed overload");
464 case OR_No_Viable_Function:
465 if (candidates.empty())
466 msg = diag::err_ovl_no_conversion_in_cast;
467 else
468 msg = diag::err_ovl_no_viable_conversion_in_cast;
469 howManyCandidates = OCD_AllCandidates;
470 break;
471
472 case OR_Ambiguous:
473 msg = diag::err_ovl_ambiguous_conversion_in_cast;
474 howManyCandidates = OCD_AmbiguousCandidates;
475 break;
476
477 case OR_Deleted:
478 msg = diag::err_ovl_deleted_conversion_in_cast;
479 howManyCandidates = OCD_ViableCandidates;
480 break;
481 }
482
483 candidates.NoteCandidates(
484 PartialDiagnosticAt(range.getBegin(),
485 S.PDiag(msg) << CT << srcType << destType << range
486 << src->getSourceRange()),
487 S, howManyCandidates, src);
488
489 return true;
490 }
491
492 /// Diagnose a failed cast.
diagnoseBadCast(Sema & S,unsigned msg,CastType castType,SourceRange opRange,Expr * src,QualType destType,bool listInitialization)493 static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
494 SourceRange opRange, Expr *src, QualType destType,
495 bool listInitialization) {
496 if (msg == diag::err_bad_cxx_cast_generic &&
497 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType,
498 listInitialization))
499 return;
500
501 S.Diag(opRange.getBegin(), msg) << castType
502 << src->getType() << destType << opRange << src->getSourceRange();
503
504 // Detect if both types are (ptr to) class, and note any incompleteness.
505 int DifferentPtrness = 0;
506 QualType From = destType;
507 if (auto Ptr = From->getAs<PointerType>()) {
508 From = Ptr->getPointeeType();
509 DifferentPtrness++;
510 }
511 QualType To = src->getType();
512 if (auto Ptr = To->getAs<PointerType>()) {
513 To = Ptr->getPointeeType();
514 DifferentPtrness--;
515 }
516 if (!DifferentPtrness) {
517 auto RecFrom = From->getAs<RecordType>();
518 auto RecTo = To->getAs<RecordType>();
519 if (RecFrom && RecTo) {
520 auto DeclFrom = RecFrom->getAsCXXRecordDecl();
521 if (!DeclFrom->isCompleteDefinition())
522 S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete) << DeclFrom;
523 auto DeclTo = RecTo->getAsCXXRecordDecl();
524 if (!DeclTo->isCompleteDefinition())
525 S.Diag(DeclTo->getLocation(), diag::note_type_incomplete) << DeclTo;
526 }
527 }
528 }
529
530 namespace {
531 /// The kind of unwrapping we did when determining whether a conversion casts
532 /// away constness.
533 enum CastAwayConstnessKind {
534 /// The conversion does not cast away constness.
535 CACK_None = 0,
536 /// We unwrapped similar types.
537 CACK_Similar = 1,
538 /// We unwrapped dissimilar types with similar representations (eg, a pointer
539 /// versus an Objective-C object pointer).
540 CACK_SimilarKind = 2,
541 /// We unwrapped representationally-unrelated types, such as a pointer versus
542 /// a pointer-to-member.
543 CACK_Incoherent = 3,
544 };
545 }
546
547 /// Unwrap one level of types for CastsAwayConstness.
548 ///
549 /// Like Sema::UnwrapSimilarTypes, this removes one level of indirection from
550 /// both types, provided that they're both pointer-like or array-like. Unlike
551 /// the Sema function, doesn't care if the unwrapped pieces are related.
552 ///
553 /// This function may remove additional levels as necessary for correctness:
554 /// the resulting T1 is unwrapped sufficiently that it is never an array type,
555 /// so that its qualifiers can be directly compared to those of T2 (which will
556 /// have the combined set of qualifiers from all indermediate levels of T2),
557 /// as (effectively) required by [expr.const.cast]p7 replacing T1's qualifiers
558 /// with those from T2.
559 static CastAwayConstnessKind
unwrapCastAwayConstnessLevel(ASTContext & Context,QualType & T1,QualType & T2)560 unwrapCastAwayConstnessLevel(ASTContext &Context, QualType &T1, QualType &T2) {
561 enum { None, Ptr, MemPtr, BlockPtr, Array };
562 auto Classify = [](QualType T) {
563 if (T->isAnyPointerType()) return Ptr;
564 if (T->isMemberPointerType()) return MemPtr;
565 if (T->isBlockPointerType()) return BlockPtr;
566 // We somewhat-arbitrarily don't look through VLA types here. This is at
567 // least consistent with the behavior of UnwrapSimilarTypes.
568 if (T->isConstantArrayType() || T->isIncompleteArrayType()) return Array;
569 return None;
570 };
571
572 auto Unwrap = [&](QualType T) {
573 if (auto *AT = Context.getAsArrayType(T))
574 return AT->getElementType();
575 return T->getPointeeType();
576 };
577
578 CastAwayConstnessKind Kind;
579
580 if (T2->isReferenceType()) {
581 // Special case: if the destination type is a reference type, unwrap it as
582 // the first level. (The source will have been an lvalue expression in this
583 // case, so there is no corresponding "reference to" in T1 to remove.) This
584 // simulates removing a "pointer to" from both sides.
585 T2 = T2->getPointeeType();
586 Kind = CastAwayConstnessKind::CACK_Similar;
587 } else if (Context.UnwrapSimilarTypes(T1, T2)) {
588 Kind = CastAwayConstnessKind::CACK_Similar;
589 } else {
590 // Try unwrapping mismatching levels.
591 int T1Class = Classify(T1);
592 if (T1Class == None)
593 return CastAwayConstnessKind::CACK_None;
594
595 int T2Class = Classify(T2);
596 if (T2Class == None)
597 return CastAwayConstnessKind::CACK_None;
598
599 T1 = Unwrap(T1);
600 T2 = Unwrap(T2);
601 Kind = T1Class == T2Class ? CastAwayConstnessKind::CACK_SimilarKind
602 : CastAwayConstnessKind::CACK_Incoherent;
603 }
604
605 // We've unwrapped at least one level. If the resulting T1 is a (possibly
606 // multidimensional) array type, any qualifier on any matching layer of
607 // T2 is considered to correspond to T1. Decompose down to the element
608 // type of T1 so that we can compare properly.
609 while (true) {
610 Context.UnwrapSimilarArrayTypes(T1, T2);
611
612 if (Classify(T1) != Array)
613 break;
614
615 auto T2Class = Classify(T2);
616 if (T2Class == None)
617 break;
618
619 if (T2Class != Array)
620 Kind = CastAwayConstnessKind::CACK_Incoherent;
621 else if (Kind != CastAwayConstnessKind::CACK_Incoherent)
622 Kind = CastAwayConstnessKind::CACK_SimilarKind;
623
624 T1 = Unwrap(T1);
625 T2 = Unwrap(T2).withCVRQualifiers(T2.getCVRQualifiers());
626 }
627
628 return Kind;
629 }
630
631 /// Check if the pointer conversion from SrcType to DestType casts away
632 /// constness as defined in C++ [expr.const.cast]. This is used by the cast
633 /// checkers. Both arguments must denote pointer (possibly to member) types.
634 ///
635 /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
636 /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
637 static CastAwayConstnessKind
CastsAwayConstness(Sema & Self,QualType SrcType,QualType DestType,bool CheckCVR,bool CheckObjCLifetime,QualType * TheOffendingSrcType=nullptr,QualType * TheOffendingDestType=nullptr,Qualifiers * CastAwayQualifiers=nullptr)638 CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
639 bool CheckCVR, bool CheckObjCLifetime,
640 QualType *TheOffendingSrcType = nullptr,
641 QualType *TheOffendingDestType = nullptr,
642 Qualifiers *CastAwayQualifiers = nullptr) {
643 // If the only checking we care about is for Objective-C lifetime qualifiers,
644 // and we're not in ObjC mode, there's nothing to check.
645 if (!CheckCVR && CheckObjCLifetime && !Self.Context.getLangOpts().ObjC)
646 return CastAwayConstnessKind::CACK_None;
647
648 if (!DestType->isReferenceType()) {
649 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
650 SrcType->isBlockPointerType()) &&
651 "Source type is not pointer or pointer to member.");
652 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
653 DestType->isBlockPointerType()) &&
654 "Destination type is not pointer or pointer to member.");
655 }
656
657 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
658 UnwrappedDestType = Self.Context.getCanonicalType(DestType);
659
660 // Find the qualifiers. We only care about cvr-qualifiers for the
661 // purpose of this check, because other qualifiers (address spaces,
662 // Objective-C GC, etc.) are part of the type's identity.
663 QualType PrevUnwrappedSrcType = UnwrappedSrcType;
664 QualType PrevUnwrappedDestType = UnwrappedDestType;
665 auto WorstKind = CastAwayConstnessKind::CACK_Similar;
666 bool AllConstSoFar = true;
667 while (auto Kind = unwrapCastAwayConstnessLevel(
668 Self.Context, UnwrappedSrcType, UnwrappedDestType)) {
669 // Track the worst kind of unwrap we needed to do before we found a
670 // problem.
671 if (Kind > WorstKind)
672 WorstKind = Kind;
673
674 // Determine the relevant qualifiers at this level.
675 Qualifiers SrcQuals, DestQuals;
676 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals);
677 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals);
678
679 // We do not meaningfully track object const-ness of Objective-C object
680 // types. Remove const from the source type if either the source or
681 // the destination is an Objective-C object type.
682 if (UnwrappedSrcType->isObjCObjectType() ||
683 UnwrappedDestType->isObjCObjectType())
684 SrcQuals.removeConst();
685
686 if (CheckCVR) {
687 Qualifiers SrcCvrQuals =
688 Qualifiers::fromCVRMask(SrcQuals.getCVRQualifiers());
689 Qualifiers DestCvrQuals =
690 Qualifiers::fromCVRMask(DestQuals.getCVRQualifiers());
691
692 if (SrcCvrQuals != DestCvrQuals) {
693 if (CastAwayQualifiers)
694 *CastAwayQualifiers = SrcCvrQuals - DestCvrQuals;
695
696 // If we removed a cvr-qualifier, this is casting away 'constness'.
697 if (!DestCvrQuals.compatiblyIncludes(SrcCvrQuals)) {
698 if (TheOffendingSrcType)
699 *TheOffendingSrcType = PrevUnwrappedSrcType;
700 if (TheOffendingDestType)
701 *TheOffendingDestType = PrevUnwrappedDestType;
702 return WorstKind;
703 }
704
705 // If any prior level was not 'const', this is also casting away
706 // 'constness'. We noted the outermost type missing a 'const' already.
707 if (!AllConstSoFar)
708 return WorstKind;
709 }
710 }
711
712 if (CheckObjCLifetime &&
713 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals))
714 return WorstKind;
715
716 // If we found our first non-const-qualified type, this may be the place
717 // where things start to go wrong.
718 if (AllConstSoFar && !DestQuals.hasConst()) {
719 AllConstSoFar = false;
720 if (TheOffendingSrcType)
721 *TheOffendingSrcType = PrevUnwrappedSrcType;
722 if (TheOffendingDestType)
723 *TheOffendingDestType = PrevUnwrappedDestType;
724 }
725
726 PrevUnwrappedSrcType = UnwrappedSrcType;
727 PrevUnwrappedDestType = UnwrappedDestType;
728 }
729
730 return CastAwayConstnessKind::CACK_None;
731 }
732
getCastAwayConstnessCastKind(CastAwayConstnessKind CACK,unsigned & DiagID)733 static TryCastResult getCastAwayConstnessCastKind(CastAwayConstnessKind CACK,
734 unsigned &DiagID) {
735 switch (CACK) {
736 case CastAwayConstnessKind::CACK_None:
737 llvm_unreachable("did not cast away constness");
738
739 case CastAwayConstnessKind::CACK_Similar:
740 // FIXME: Accept these as an extension too?
741 case CastAwayConstnessKind::CACK_SimilarKind:
742 DiagID = diag::err_bad_cxx_cast_qualifiers_away;
743 return TC_Failed;
744
745 case CastAwayConstnessKind::CACK_Incoherent:
746 DiagID = diag::ext_bad_cxx_cast_qualifiers_away_incoherent;
747 return TC_Extension;
748 }
749
750 llvm_unreachable("unexpected cast away constness kind");
751 }
752
753 /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
754 /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
755 /// checked downcasts in class hierarchies.
CheckDynamicCast()756 void CastOperation::CheckDynamicCast() {
757 CheckNoDerefRAII NoderefCheck(*this);
758
759 if (ValueKind == VK_PRValue)
760 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
761 else if (isPlaceholder())
762 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
763 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
764 return;
765
766 QualType OrigSrcType = SrcExpr.get()->getType();
767 QualType DestType = Self.Context.getCanonicalType(this->DestType);
768
769 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
770 // or "pointer to cv void".
771
772 QualType DestPointee;
773 const PointerType *DestPointer = DestType->getAs<PointerType>();
774 const ReferenceType *DestReference = nullptr;
775 if (DestPointer) {
776 DestPointee = DestPointer->getPointeeType();
777 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
778 DestPointee = DestReference->getPointeeType();
779 } else {
780 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
781 << this->DestType << DestRange;
782 SrcExpr = ExprError();
783 return;
784 }
785
786 const RecordType *DestRecord = DestPointee->getAs<RecordType>();
787 if (DestPointee->isVoidType()) {
788 assert(DestPointer && "Reference to void is not possible");
789 } else if (DestRecord) {
790 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee,
791 diag::err_bad_cast_incomplete,
792 DestRange)) {
793 SrcExpr = ExprError();
794 return;
795 }
796 } else {
797 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
798 << DestPointee.getUnqualifiedType() << DestRange;
799 SrcExpr = ExprError();
800 return;
801 }
802
803 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
804 // complete class type, [...]. If T is an lvalue reference type, v shall be
805 // an lvalue of a complete class type, [...]. If T is an rvalue reference
806 // type, v shall be an expression having a complete class type, [...]
807 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
808 QualType SrcPointee;
809 if (DestPointer) {
810 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
811 SrcPointee = SrcPointer->getPointeeType();
812 } else {
813 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
814 << OrigSrcType << this->DestType << SrcExpr.get()->getSourceRange();
815 SrcExpr = ExprError();
816 return;
817 }
818 } else if (DestReference->isLValueReferenceType()) {
819 if (!SrcExpr.get()->isLValue()) {
820 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
821 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
822 }
823 SrcPointee = SrcType;
824 } else {
825 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
826 // to materialize the prvalue before we bind the reference to it.
827 if (SrcExpr.get()->isPRValue())
828 SrcExpr = Self.CreateMaterializeTemporaryExpr(
829 SrcType, SrcExpr.get(), /*IsLValueReference*/ false);
830 SrcPointee = SrcType;
831 }
832
833 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
834 if (SrcRecord) {
835 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
836 diag::err_bad_cast_incomplete,
837 SrcExpr.get())) {
838 SrcExpr = ExprError();
839 return;
840 }
841 } else {
842 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
843 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
844 SrcExpr = ExprError();
845 return;
846 }
847
848 assert((DestPointer || DestReference) &&
849 "Bad destination non-ptr/ref slipped through.");
850 assert((DestRecord || DestPointee->isVoidType()) &&
851 "Bad destination pointee slipped through.");
852 assert(SrcRecord && "Bad source pointee slipped through.");
853
854 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
855 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
856 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away)
857 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
858 SrcExpr = ExprError();
859 return;
860 }
861
862 // C++ 5.2.7p3: If the type of v is the same as the required result type,
863 // [except for cv].
864 if (DestRecord == SrcRecord) {
865 Kind = CK_NoOp;
866 return;
867 }
868
869 // C++ 5.2.7p5
870 // Upcasts are resolved statically.
871 if (DestRecord &&
872 Self.IsDerivedFrom(OpRange.getBegin(), SrcPointee, DestPointee)) {
873 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
874 OpRange.getBegin(), OpRange,
875 &BasePath)) {
876 SrcExpr = ExprError();
877 return;
878 }
879
880 Kind = CK_DerivedToBase;
881 return;
882 }
883
884 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
885 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
886 assert(SrcDecl && "Definition missing");
887 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
888 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
889 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
890 SrcExpr = ExprError();
891 }
892
893 // dynamic_cast is not available with -fno-rtti.
894 // As an exception, dynamic_cast to void* is available because it doesn't
895 // use RTTI.
896 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
897 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti);
898 SrcExpr = ExprError();
899 return;
900 }
901
902 // Warns when dynamic_cast is used with RTTI data disabled.
903 if (!Self.getLangOpts().RTTIData) {
904 bool MicrosoftABI =
905 Self.getASTContext().getTargetInfo().getCXXABI().isMicrosoft();
906 bool isClangCL = Self.getDiagnostics().getDiagnosticOptions().getFormat() ==
907 DiagnosticOptions::MSVC;
908 if (MicrosoftABI || !DestPointee->isVoidType())
909 Self.Diag(OpRange.getBegin(),
910 diag::warn_no_dynamic_cast_with_rtti_disabled)
911 << isClangCL;
912 }
913
914 // Done. Everything else is run-time checks.
915 Kind = CK_Dynamic;
916 }
917
918 /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
919 /// Refer to C++ 5.2.11 for details. const_cast is typically used in code
920 /// like this:
921 /// const char *str = "literal";
922 /// legacy_function(const_cast\<char*\>(str));
CheckConstCast()923 void CastOperation::CheckConstCast() {
924 CheckNoDerefRAII NoderefCheck(*this);
925
926 if (ValueKind == VK_PRValue)
927 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
928 else if (isPlaceholder())
929 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
930 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
931 return;
932
933 unsigned msg = diag::err_bad_cxx_cast_generic;
934 auto TCR = TryConstCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg);
935 if (TCR != TC_Success && msg != 0) {
936 Self.Diag(OpRange.getBegin(), msg) << CT_Const
937 << SrcExpr.get()->getType() << DestType << OpRange;
938 }
939 if (!isValidCast(TCR))
940 SrcExpr = ExprError();
941 }
942
CheckAddrspaceCast()943 void CastOperation::CheckAddrspaceCast() {
944 unsigned msg = diag::err_bad_cxx_cast_generic;
945 auto TCR =
946 TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg, Kind);
947 if (TCR != TC_Success && msg != 0) {
948 Self.Diag(OpRange.getBegin(), msg)
949 << CT_Addrspace << SrcExpr.get()->getType() << DestType << OpRange;
950 }
951 if (!isValidCast(TCR))
952 SrcExpr = ExprError();
953 }
954
955 /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
956 /// or downcast between respective pointers or references.
DiagnoseReinterpretUpDownCast(Sema & Self,const Expr * SrcExpr,QualType DestType,SourceRange OpRange)957 static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
958 QualType DestType,
959 SourceRange OpRange) {
960 QualType SrcType = SrcExpr->getType();
961 // When casting from pointer or reference, get pointee type; use original
962 // type otherwise.
963 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
964 const CXXRecordDecl *SrcRD =
965 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
966
967 // Examining subobjects for records is only possible if the complete and
968 // valid definition is available. Also, template instantiation is not
969 // allowed here.
970 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
971 return;
972
973 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
974
975 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
976 return;
977
978 enum {
979 ReinterpretUpcast,
980 ReinterpretDowncast
981 } ReinterpretKind;
982
983 CXXBasePaths BasePaths;
984
985 if (SrcRD->isDerivedFrom(DestRD, BasePaths))
986 ReinterpretKind = ReinterpretUpcast;
987 else if (DestRD->isDerivedFrom(SrcRD, BasePaths))
988 ReinterpretKind = ReinterpretDowncast;
989 else
990 return;
991
992 bool VirtualBase = true;
993 bool NonZeroOffset = false;
994 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
995 E = BasePaths.end();
996 I != E; ++I) {
997 const CXXBasePath &Path = *I;
998 CharUnits Offset = CharUnits::Zero();
999 bool IsVirtual = false;
1000 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
1001 IElem != EElem; ++IElem) {
1002 IsVirtual = IElem->Base->isVirtual();
1003 if (IsVirtual)
1004 break;
1005 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
1006 assert(BaseRD && "Base type should be a valid unqualified class type");
1007 // Don't check if any base has invalid declaration or has no definition
1008 // since it has no layout info.
1009 const CXXRecordDecl *Class = IElem->Class,
1010 *ClassDefinition = Class->getDefinition();
1011 if (Class->isInvalidDecl() || !ClassDefinition ||
1012 !ClassDefinition->isCompleteDefinition())
1013 return;
1014
1015 const ASTRecordLayout &DerivedLayout =
1016 Self.Context.getASTRecordLayout(Class);
1017 Offset += DerivedLayout.getBaseClassOffset(BaseRD);
1018 }
1019 if (!IsVirtual) {
1020 // Don't warn if any path is a non-virtually derived base at offset zero.
1021 if (Offset.isZero())
1022 return;
1023 // Offset makes sense only for non-virtual bases.
1024 else
1025 NonZeroOffset = true;
1026 }
1027 VirtualBase = VirtualBase && IsVirtual;
1028 }
1029
1030 (void) NonZeroOffset; // Silence set but not used warning.
1031 assert((VirtualBase || NonZeroOffset) &&
1032 "Should have returned if has non-virtual base with zero offset");
1033
1034 QualType BaseType =
1035 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
1036 QualType DerivedType =
1037 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
1038
1039 SourceLocation BeginLoc = OpRange.getBegin();
1040 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static)
1041 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
1042 << OpRange;
1043 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static)
1044 << int(ReinterpretKind)
1045 << FixItHint::CreateReplacement(BeginLoc, "static_cast");
1046 }
1047
argTypeIsABIEquivalent(QualType SrcType,QualType DestType,ASTContext & Context)1048 static bool argTypeIsABIEquivalent(QualType SrcType, QualType DestType,
1049 ASTContext &Context) {
1050 if (SrcType->isPointerType() && DestType->isPointerType())
1051 return true;
1052
1053 // Allow integral type mismatch if their size are equal.
1054 if (SrcType->isIntegralType(Context) && DestType->isIntegralType(Context))
1055 if (Context.getTypeInfoInChars(SrcType).Width ==
1056 Context.getTypeInfoInChars(DestType).Width)
1057 return true;
1058
1059 return Context.hasSameUnqualifiedType(SrcType, DestType);
1060 }
1061
checkCastFunctionType(Sema & Self,const ExprResult & SrcExpr,QualType DestType)1062 static bool checkCastFunctionType(Sema &Self, const ExprResult &SrcExpr,
1063 QualType DestType) {
1064 if (Self.Diags.isIgnored(diag::warn_cast_function_type,
1065 SrcExpr.get()->getExprLoc()))
1066 return true;
1067
1068 QualType SrcType = SrcExpr.get()->getType();
1069 const FunctionType *SrcFTy = nullptr;
1070 const FunctionType *DstFTy = nullptr;
1071 if (((SrcType->isBlockPointerType() || SrcType->isFunctionPointerType()) &&
1072 DestType->isFunctionPointerType()) ||
1073 (SrcType->isMemberFunctionPointerType() &&
1074 DestType->isMemberFunctionPointerType())) {
1075 SrcFTy = SrcType->getPointeeType()->castAs<FunctionType>();
1076 DstFTy = DestType->getPointeeType()->castAs<FunctionType>();
1077 } else if (SrcType->isFunctionType() && DestType->isFunctionReferenceType()) {
1078 SrcFTy = SrcType->castAs<FunctionType>();
1079 DstFTy = DestType.getNonReferenceType()->castAs<FunctionType>();
1080 } else {
1081 return true;
1082 }
1083 assert(SrcFTy && DstFTy);
1084
1085 auto IsVoidVoid = [](const FunctionType *T) {
1086 if (!T->getReturnType()->isVoidType())
1087 return false;
1088 if (const auto *PT = T->getAs<FunctionProtoType>())
1089 return !PT->isVariadic() && PT->getNumParams() == 0;
1090 return false;
1091 };
1092
1093 // Skip if either function type is void(*)(void)
1094 if (IsVoidVoid(SrcFTy) || IsVoidVoid(DstFTy))
1095 return true;
1096
1097 // Check return type.
1098 if (!argTypeIsABIEquivalent(SrcFTy->getReturnType(), DstFTy->getReturnType(),
1099 Self.Context))
1100 return false;
1101
1102 // Check if either has unspecified number of parameters
1103 if (SrcFTy->isFunctionNoProtoType() || DstFTy->isFunctionNoProtoType())
1104 return true;
1105
1106 // Check parameter types.
1107
1108 const auto *SrcFPTy = cast<FunctionProtoType>(SrcFTy);
1109 const auto *DstFPTy = cast<FunctionProtoType>(DstFTy);
1110
1111 // In a cast involving function types with a variable argument list only the
1112 // types of initial arguments that are provided are considered.
1113 unsigned NumParams = SrcFPTy->getNumParams();
1114 unsigned DstNumParams = DstFPTy->getNumParams();
1115 if (NumParams > DstNumParams) {
1116 if (!DstFPTy->isVariadic())
1117 return false;
1118 NumParams = DstNumParams;
1119 } else if (NumParams < DstNumParams) {
1120 if (!SrcFPTy->isVariadic())
1121 return false;
1122 }
1123
1124 for (unsigned i = 0; i < NumParams; ++i)
1125 if (!argTypeIsABIEquivalent(SrcFPTy->getParamType(i),
1126 DstFPTy->getParamType(i), Self.Context))
1127 return false;
1128
1129 return true;
1130 }
1131
1132 /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
1133 /// valid.
1134 /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
1135 /// like this:
1136 /// char *bytes = reinterpret_cast\<char*\>(int_ptr);
CheckReinterpretCast()1137 void CastOperation::CheckReinterpretCast() {
1138 if (ValueKind == VK_PRValue && !isPlaceholder(BuiltinType::Overload))
1139 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
1140 else
1141 checkNonOverloadPlaceholders();
1142 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1143 return;
1144
1145 unsigned msg = diag::err_bad_cxx_cast_generic;
1146 TryCastResult tcr =
1147 TryReinterpretCast(Self, SrcExpr, DestType,
1148 /*CStyle*/false, OpRange, msg, Kind);
1149 if (tcr != TC_Success && msg != 0) {
1150 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1151 return;
1152 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1153 //FIXME: &f<int>; is overloaded and resolvable
1154 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload)
1155 << OverloadExpr::find(SrcExpr.get()).Expression->getName()
1156 << DestType << OpRange;
1157 Self.NoteAllOverloadCandidates(SrcExpr.get());
1158
1159 } else {
1160 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(),
1161 DestType, /*listInitialization=*/false);
1162 }
1163 }
1164
1165 if (isValidCast(tcr)) {
1166 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1167 checkObjCConversion(Sema::CCK_OtherCast);
1168 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
1169
1170 if (!checkCastFunctionType(Self, SrcExpr, DestType))
1171 Self.Diag(OpRange.getBegin(), diag::warn_cast_function_type)
1172 << SrcExpr.get()->getType() << DestType << OpRange;
1173 } else {
1174 SrcExpr = ExprError();
1175 }
1176 }
1177
1178
1179 /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
1180 /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
1181 /// implicit conversions explicit and getting rid of data loss warnings.
CheckStaticCast()1182 void CastOperation::CheckStaticCast() {
1183 CheckNoDerefRAII NoderefCheck(*this);
1184
1185 if (isPlaceholder()) {
1186 checkNonOverloadPlaceholders();
1187 if (SrcExpr.isInvalid())
1188 return;
1189 }
1190
1191 // This test is outside everything else because it's the only case where
1192 // a non-lvalue-reference target type does not lead to decay.
1193 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1194 if (DestType->isVoidType()) {
1195 Kind = CK_ToVoid;
1196
1197 if (claimPlaceholder(BuiltinType::Overload)) {
1198 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
1199 false, // Decay Function to ptr
1200 true, // Complain
1201 OpRange, DestType, diag::err_bad_static_cast_overload);
1202 if (SrcExpr.isInvalid())
1203 return;
1204 }
1205
1206 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
1207 return;
1208 }
1209
1210 if (ValueKind == VK_PRValue && !DestType->isRecordType() &&
1211 !isPlaceholder(BuiltinType::Overload)) {
1212 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
1213 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1214 return;
1215 }
1216
1217 unsigned msg = diag::err_bad_cxx_cast_generic;
1218 TryCastResult tcr
1219 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg,
1220 Kind, BasePath, /*ListInitialization=*/false);
1221 if (tcr != TC_Success && msg != 0) {
1222 if (SrcExpr.isInvalid())
1223 return;
1224 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1225 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression;
1226 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload)
1227 << oe->getName() << DestType << OpRange
1228 << oe->getQualifierLoc().getSourceRange();
1229 Self.NoteAllOverloadCandidates(SrcExpr.get());
1230 } else {
1231 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType,
1232 /*listInitialization=*/false);
1233 }
1234 }
1235
1236 if (isValidCast(tcr)) {
1237 if (Kind == CK_BitCast)
1238 checkCastAlign();
1239 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1240 checkObjCConversion(Sema::CCK_OtherCast);
1241 } else {
1242 SrcExpr = ExprError();
1243 }
1244 }
1245
IsAddressSpaceConversion(QualType SrcType,QualType DestType)1246 static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) {
1247 auto *SrcPtrType = SrcType->getAs<PointerType>();
1248 if (!SrcPtrType)
1249 return false;
1250 auto *DestPtrType = DestType->getAs<PointerType>();
1251 if (!DestPtrType)
1252 return false;
1253 return SrcPtrType->getPointeeType().getAddressSpace() !=
1254 DestPtrType->getPointeeType().getAddressSpace();
1255 }
1256
1257 /// TryStaticCast - Check if a static cast can be performed, and do so if
1258 /// possible. If @p CStyle, ignore access restrictions on hierarchy casting
1259 /// and casting away constness.
TryStaticCast(Sema & Self,ExprResult & SrcExpr,QualType DestType,Sema::CheckedConversionKind CCK,SourceRange OpRange,unsigned & msg,CastKind & Kind,CXXCastPath & BasePath,bool ListInitialization)1260 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
1261 QualType DestType,
1262 Sema::CheckedConversionKind CCK,
1263 SourceRange OpRange, unsigned &msg,
1264 CastKind &Kind, CXXCastPath &BasePath,
1265 bool ListInitialization) {
1266 // Determine whether we have the semantics of a C-style cast.
1267 bool CStyle
1268 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1269
1270 // The order the tests is not entirely arbitrary. There is one conversion
1271 // that can be handled in two different ways. Given:
1272 // struct A {};
1273 // struct B : public A {
1274 // B(); B(const A&);
1275 // };
1276 // const A &a = B();
1277 // the cast static_cast<const B&>(a) could be seen as either a static
1278 // reference downcast, or an explicit invocation of the user-defined
1279 // conversion using B's conversion constructor.
1280 // DR 427 specifies that the downcast is to be applied here.
1281
1282 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1283 // Done outside this function.
1284
1285 TryCastResult tcr;
1286
1287 // C++ 5.2.9p5, reference downcast.
1288 // See the function for details.
1289 // DR 427 specifies that this is to be applied before paragraph 2.
1290 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle,
1291 OpRange, msg, Kind, BasePath);
1292 if (tcr != TC_NotApplicable)
1293 return tcr;
1294
1295 // C++11 [expr.static.cast]p3:
1296 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
1297 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1298 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind,
1299 BasePath, msg);
1300 if (tcr != TC_NotApplicable)
1301 return tcr;
1302
1303 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
1304 // [...] if the declaration "T t(e);" is well-formed, [...].
1305 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
1306 Kind, ListInitialization);
1307 if (SrcExpr.isInvalid())
1308 return TC_Failed;
1309 if (tcr != TC_NotApplicable)
1310 return tcr;
1311
1312 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
1313 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
1314 // conversions, subject to further restrictions.
1315 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
1316 // of qualification conversions impossible.
1317 // In the CStyle case, the earlier attempt to const_cast should have taken
1318 // care of reverse qualification conversions.
1319
1320 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType());
1321
1322 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
1323 // converted to an integral type. [...] A value of a scoped enumeration type
1324 // can also be explicitly converted to a floating-point type [...].
1325 if (const EnumType *Enum = SrcType->getAs<EnumType>()) {
1326 if (Enum->getDecl()->isScoped()) {
1327 if (DestType->isBooleanType()) {
1328 Kind = CK_IntegralToBoolean;
1329 return TC_Success;
1330 } else if (DestType->isIntegralType(Self.Context)) {
1331 Kind = CK_IntegralCast;
1332 return TC_Success;
1333 } else if (DestType->isRealFloatingType()) {
1334 Kind = CK_IntegralToFloating;
1335 return TC_Success;
1336 }
1337 }
1338 }
1339
1340 // Reverse integral promotion/conversion. All such conversions are themselves
1341 // again integral promotions or conversions and are thus already handled by
1342 // p2 (TryDirectInitialization above).
1343 // (Note: any data loss warnings should be suppressed.)
1344 // The exception is the reverse of enum->integer, i.e. integer->enum (and
1345 // enum->enum). See also C++ 5.2.9p7.
1346 // The same goes for reverse floating point promotion/conversion and
1347 // floating-integral conversions. Again, only floating->enum is relevant.
1348 if (DestType->isEnumeralType()) {
1349 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1350 diag::err_bad_cast_incomplete)) {
1351 SrcExpr = ExprError();
1352 return TC_Failed;
1353 }
1354 if (SrcType->isIntegralOrEnumerationType()) {
1355 // [expr.static.cast]p10 If the enumeration type has a fixed underlying
1356 // type, the value is first converted to that type by integral conversion
1357 const EnumType *Enum = DestType->getAs<EnumType>();
1358 Kind = Enum->getDecl()->isFixed() &&
1359 Enum->getDecl()->getIntegerType()->isBooleanType()
1360 ? CK_IntegralToBoolean
1361 : CK_IntegralCast;
1362 return TC_Success;
1363 } else if (SrcType->isRealFloatingType()) {
1364 Kind = CK_FloatingToIntegral;
1365 return TC_Success;
1366 }
1367 }
1368
1369 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1370 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1371 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1372 Kind, BasePath);
1373 if (tcr != TC_NotApplicable)
1374 return tcr;
1375
1376 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1377 // conversion. C++ 5.2.9p9 has additional information.
1378 // DR54's access restrictions apply here also.
1379 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1380 OpRange, msg, Kind, BasePath);
1381 if (tcr != TC_NotApplicable)
1382 return tcr;
1383
1384 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1385 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1386 // just the usual constness stuff.
1387 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1388 QualType SrcPointee = SrcPointer->getPointeeType();
1389 if (SrcPointee->isVoidType()) {
1390 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1391 QualType DestPointee = DestPointer->getPointeeType();
1392 if (DestPointee->isIncompleteOrObjectType()) {
1393 // This is definitely the intended conversion, but it might fail due
1394 // to a qualifier violation. Note that we permit Objective-C lifetime
1395 // and GC qualifier mismatches here.
1396 if (!CStyle) {
1397 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1398 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1399 DestPointeeQuals.removeObjCGCAttr();
1400 DestPointeeQuals.removeObjCLifetime();
1401 SrcPointeeQuals.removeObjCGCAttr();
1402 SrcPointeeQuals.removeObjCLifetime();
1403 if (DestPointeeQuals != SrcPointeeQuals &&
1404 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) {
1405 msg = diag::err_bad_cxx_cast_qualifiers_away;
1406 return TC_Failed;
1407 }
1408 }
1409 Kind = IsAddressSpaceConversion(SrcType, DestType)
1410 ? CK_AddressSpaceConversion
1411 : CK_BitCast;
1412 return TC_Success;
1413 }
1414
1415 // Microsoft permits static_cast from 'pointer-to-void' to
1416 // 'pointer-to-function'.
1417 if (!CStyle && Self.getLangOpts().MSVCCompat &&
1418 DestPointee->isFunctionType()) {
1419 Self.Diag(OpRange.getBegin(), diag::ext_ms_cast_fn_obj) << OpRange;
1420 Kind = CK_BitCast;
1421 return TC_Success;
1422 }
1423 }
1424 else if (DestType->isObjCObjectPointerType()) {
1425 // allow both c-style cast and static_cast of objective-c pointers as
1426 // they are pervasive.
1427 Kind = CK_CPointerToObjCPointerCast;
1428 return TC_Success;
1429 }
1430 else if (CStyle && DestType->isBlockPointerType()) {
1431 // allow c-style cast of void * to block pointers.
1432 Kind = CK_AnyPointerToBlockPointerCast;
1433 return TC_Success;
1434 }
1435 }
1436 }
1437 // Allow arbitrary objective-c pointer conversion with static casts.
1438 if (SrcType->isObjCObjectPointerType() &&
1439 DestType->isObjCObjectPointerType()) {
1440 Kind = CK_BitCast;
1441 return TC_Success;
1442 }
1443 // Allow ns-pointer to cf-pointer conversion in either direction
1444 // with static casts.
1445 if (!CStyle &&
1446 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
1447 return TC_Success;
1448
1449 // See if it looks like the user is trying to convert between
1450 // related record types, and select a better diagnostic if so.
1451 if (auto SrcPointer = SrcType->getAs<PointerType>())
1452 if (auto DestPointer = DestType->getAs<PointerType>())
1453 if (SrcPointer->getPointeeType()->getAs<RecordType>() &&
1454 DestPointer->getPointeeType()->getAs<RecordType>())
1455 msg = diag::err_bad_cxx_cast_unrelated_class;
1456
1457 if (SrcType->isMatrixType() && DestType->isMatrixType()) {
1458 if (Self.CheckMatrixCast(OpRange, DestType, SrcType, Kind)) {
1459 SrcExpr = ExprError();
1460 return TC_Failed;
1461 }
1462 return TC_Success;
1463 }
1464
1465 // We tried everything. Everything! Nothing works! :-(
1466 return TC_NotApplicable;
1467 }
1468
1469 /// Tests whether a conversion according to N2844 is valid.
TryLValueToRValueCast(Sema & Self,Expr * SrcExpr,QualType DestType,bool CStyle,CastKind & Kind,CXXCastPath & BasePath,unsigned & msg)1470 TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
1471 QualType DestType, bool CStyle,
1472 CastKind &Kind, CXXCastPath &BasePath,
1473 unsigned &msg) {
1474 // C++11 [expr.static.cast]p3:
1475 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1476 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1477 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1478 if (!R)
1479 return TC_NotApplicable;
1480
1481 if (!SrcExpr->isGLValue())
1482 return TC_NotApplicable;
1483
1484 // Because we try the reference downcast before this function, from now on
1485 // this is the only cast possibility, so we issue an error if we fail now.
1486 // FIXME: Should allow casting away constness if CStyle.
1487 QualType FromType = SrcExpr->getType();
1488 QualType ToType = R->getPointeeType();
1489 if (CStyle) {
1490 FromType = FromType.getUnqualifiedType();
1491 ToType = ToType.getUnqualifiedType();
1492 }
1493
1494 Sema::ReferenceConversions RefConv;
1495 Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship(
1496 SrcExpr->getBeginLoc(), ToType, FromType, &RefConv);
1497 if (RefResult != Sema::Ref_Compatible) {
1498 if (CStyle || RefResult == Sema::Ref_Incompatible)
1499 return TC_NotApplicable;
1500 // Diagnose types which are reference-related but not compatible here since
1501 // we can provide better diagnostics. In these cases forwarding to
1502 // [expr.static.cast]p4 should never result in a well-formed cast.
1503 msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast
1504 : diag::err_bad_rvalue_to_rvalue_cast;
1505 return TC_Failed;
1506 }
1507
1508 if (RefConv & Sema::ReferenceConversions::DerivedToBase) {
1509 Kind = CK_DerivedToBase;
1510 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1511 /*DetectVirtual=*/true);
1512 if (!Self.IsDerivedFrom(SrcExpr->getBeginLoc(), SrcExpr->getType(),
1513 R->getPointeeType(), Paths))
1514 return TC_NotApplicable;
1515
1516 Self.BuildBasePathArray(Paths, BasePath);
1517 } else
1518 Kind = CK_NoOp;
1519
1520 return TC_Success;
1521 }
1522
1523 /// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1524 TryCastResult
TryStaticReferenceDowncast(Sema & Self,Expr * SrcExpr,QualType DestType,bool CStyle,SourceRange OpRange,unsigned & msg,CastKind & Kind,CXXCastPath & BasePath)1525 TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
1526 bool CStyle, SourceRange OpRange,
1527 unsigned &msg, CastKind &Kind,
1528 CXXCastPath &BasePath) {
1529 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1530 // cast to type "reference to cv2 D", where D is a class derived from B,
1531 // if a valid standard conversion from "pointer to D" to "pointer to B"
1532 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1533 // In addition, DR54 clarifies that the base must be accessible in the
1534 // current context. Although the wording of DR54 only applies to the pointer
1535 // variant of this rule, the intent is clearly for it to apply to the this
1536 // conversion as well.
1537
1538 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1539 if (!DestReference) {
1540 return TC_NotApplicable;
1541 }
1542 bool RValueRef = DestReference->isRValueReferenceType();
1543 if (!RValueRef && !SrcExpr->isLValue()) {
1544 // We know the left side is an lvalue reference, so we can suggest a reason.
1545 msg = diag::err_bad_cxx_cast_rvalue;
1546 return TC_NotApplicable;
1547 }
1548
1549 QualType DestPointee = DestReference->getPointeeType();
1550
1551 // FIXME: If the source is a prvalue, we should issue a warning (because the
1552 // cast always has undefined behavior), and for AST consistency, we should
1553 // materialize a temporary.
1554 return TryStaticDowncast(Self,
1555 Self.Context.getCanonicalType(SrcExpr->getType()),
1556 Self.Context.getCanonicalType(DestPointee), CStyle,
1557 OpRange, SrcExpr->getType(), DestType, msg, Kind,
1558 BasePath);
1559 }
1560
1561 /// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1562 TryCastResult
TryStaticPointerDowncast(Sema & Self,QualType SrcType,QualType DestType,bool CStyle,SourceRange OpRange,unsigned & msg,CastKind & Kind,CXXCastPath & BasePath)1563 TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
1564 bool CStyle, SourceRange OpRange,
1565 unsigned &msg, CastKind &Kind,
1566 CXXCastPath &BasePath) {
1567 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1568 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1569 // is a class derived from B, if a valid standard conversion from "pointer
1570 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1571 // class of D.
1572 // In addition, DR54 clarifies that the base must be accessible in the
1573 // current context.
1574
1575 const PointerType *DestPointer = DestType->getAs<PointerType>();
1576 if (!DestPointer) {
1577 return TC_NotApplicable;
1578 }
1579
1580 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1581 if (!SrcPointer) {
1582 msg = diag::err_bad_static_cast_pointer_nonpointer;
1583 return TC_NotApplicable;
1584 }
1585
1586 return TryStaticDowncast(Self,
1587 Self.Context.getCanonicalType(SrcPointer->getPointeeType()),
1588 Self.Context.getCanonicalType(DestPointer->getPointeeType()),
1589 CStyle, OpRange, SrcType, DestType, msg, Kind,
1590 BasePath);
1591 }
1592
1593 /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1594 /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1595 /// DestType is possible and allowed.
1596 TryCastResult
TryStaticDowncast(Sema & Self,CanQualType SrcType,CanQualType DestType,bool CStyle,SourceRange OpRange,QualType OrigSrcType,QualType OrigDestType,unsigned & msg,CastKind & Kind,CXXCastPath & BasePath)1597 TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType,
1598 bool CStyle, SourceRange OpRange, QualType OrigSrcType,
1599 QualType OrigDestType, unsigned &msg,
1600 CastKind &Kind, CXXCastPath &BasePath) {
1601 // We can only work with complete types. But don't complain if it doesn't work
1602 if (!Self.isCompleteType(OpRange.getBegin(), SrcType) ||
1603 !Self.isCompleteType(OpRange.getBegin(), DestType))
1604 return TC_NotApplicable;
1605
1606 // Downcast can only happen in class hierarchies, so we need classes.
1607 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1608 return TC_NotApplicable;
1609 }
1610
1611 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1612 /*DetectVirtual=*/true);
1613 if (!Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths)) {
1614 return TC_NotApplicable;
1615 }
1616
1617 // Target type does derive from source type. Now we're serious. If an error
1618 // appears now, it's not ignored.
1619 // This may not be entirely in line with the standard. Take for example:
1620 // struct A {};
1621 // struct B : virtual A {
1622 // B(A&);
1623 // };
1624 //
1625 // void f()
1626 // {
1627 // (void)static_cast<const B&>(*((A*)0));
1628 // }
1629 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1630 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1631 // However, both GCC and Comeau reject this example, and accepting it would
1632 // mean more complex code if we're to preserve the nice error message.
1633 // FIXME: Being 100% compliant here would be nice to have.
1634
1635 // Must preserve cv, as always, unless we're in C-style mode.
1636 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) {
1637 msg = diag::err_bad_cxx_cast_qualifiers_away;
1638 return TC_Failed;
1639 }
1640
1641 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
1642 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1643 // that it builds the paths in reverse order.
1644 // To sum up: record all paths to the base and build a nice string from
1645 // them. Use it to spice up the error message.
1646 if (!Paths.isRecordingPaths()) {
1647 Paths.clear();
1648 Paths.setRecordingPaths(true);
1649 Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths);
1650 }
1651 std::string PathDisplayStr;
1652 std::set<unsigned> DisplayedPaths;
1653 for (clang::CXXBasePath &Path : Paths) {
1654 if (DisplayedPaths.insert(Path.back().SubobjectNumber).second) {
1655 // We haven't displayed a path to this particular base
1656 // class subobject yet.
1657 PathDisplayStr += "\n ";
1658 for (CXXBasePathElement &PE : llvm::reverse(Path))
1659 PathDisplayStr += PE.Base->getType().getAsString() + " -> ";
1660 PathDisplayStr += QualType(DestType).getAsString();
1661 }
1662 }
1663
1664 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
1665 << QualType(SrcType).getUnqualifiedType()
1666 << QualType(DestType).getUnqualifiedType()
1667 << PathDisplayStr << OpRange;
1668 msg = 0;
1669 return TC_Failed;
1670 }
1671
1672 if (Paths.getDetectedVirtual() != nullptr) {
1673 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1674 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
1675 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1676 msg = 0;
1677 return TC_Failed;
1678 }
1679
1680 if (!CStyle) {
1681 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1682 SrcType, DestType,
1683 Paths.front(),
1684 diag::err_downcast_from_inaccessible_base)) {
1685 case Sema::AR_accessible:
1686 case Sema::AR_delayed: // be optimistic
1687 case Sema::AR_dependent: // be optimistic
1688 break;
1689
1690 case Sema::AR_inaccessible:
1691 msg = 0;
1692 return TC_Failed;
1693 }
1694 }
1695
1696 Self.BuildBasePathArray(Paths, BasePath);
1697 Kind = CK_BaseToDerived;
1698 return TC_Success;
1699 }
1700
1701 /// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1702 /// C++ 5.2.9p9 is valid:
1703 ///
1704 /// An rvalue of type "pointer to member of D of type cv1 T" can be
1705 /// converted to an rvalue of type "pointer to member of B of type cv2 T",
1706 /// where B is a base class of D [...].
1707 ///
1708 TryCastResult
TryStaticMemberPointerUpcast(Sema & Self,ExprResult & SrcExpr,QualType SrcType,QualType DestType,bool CStyle,SourceRange OpRange,unsigned & msg,CastKind & Kind,CXXCastPath & BasePath)1709 TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
1710 QualType DestType, bool CStyle,
1711 SourceRange OpRange,
1712 unsigned &msg, CastKind &Kind,
1713 CXXCastPath &BasePath) {
1714 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1715 if (!DestMemPtr)
1716 return TC_NotApplicable;
1717
1718 bool WasOverloadedFunction = false;
1719 DeclAccessPair FoundOverload;
1720 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1721 if (FunctionDecl *Fn
1722 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false,
1723 FoundOverload)) {
1724 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
1725 SrcType = Self.Context.getMemberPointerType(Fn->getType(),
1726 Self.Context.getTypeDeclType(M->getParent()).getTypePtr());
1727 WasOverloadedFunction = true;
1728 }
1729 }
1730
1731 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1732 if (!SrcMemPtr) {
1733 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1734 return TC_NotApplicable;
1735 }
1736
1737 // Lock down the inheritance model right now in MS ABI, whether or not the
1738 // pointee types are the same.
1739 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1740 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
1741 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
1742 }
1743
1744 // T == T, modulo cv
1745 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(),
1746 DestMemPtr->getPointeeType()))
1747 return TC_NotApplicable;
1748
1749 // B base of D
1750 QualType SrcClass(SrcMemPtr->getClass(), 0);
1751 QualType DestClass(DestMemPtr->getClass(), 0);
1752 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1753 /*DetectVirtual=*/true);
1754 if (!Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths))
1755 return TC_NotApplicable;
1756
1757 // B is a base of D. But is it an allowed base? If not, it's a hard error.
1758 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) {
1759 Paths.clear();
1760 Paths.setRecordingPaths(true);
1761 bool StillOkay =
1762 Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths);
1763 assert(StillOkay);
1764 (void)StillOkay;
1765 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths);
1766 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv)
1767 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange;
1768 msg = 0;
1769 return TC_Failed;
1770 }
1771
1772 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
1773 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
1774 << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
1775 msg = 0;
1776 return TC_Failed;
1777 }
1778
1779 if (!CStyle) {
1780 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1781 DestClass, SrcClass,
1782 Paths.front(),
1783 diag::err_upcast_to_inaccessible_base)) {
1784 case Sema::AR_accessible:
1785 case Sema::AR_delayed:
1786 case Sema::AR_dependent:
1787 // Optimistically assume that the delayed and dependent cases
1788 // will work out.
1789 break;
1790
1791 case Sema::AR_inaccessible:
1792 msg = 0;
1793 return TC_Failed;
1794 }
1795 }
1796
1797 if (WasOverloadedFunction) {
1798 // Resolve the address of the overloaded function again, this time
1799 // allowing complaints if something goes wrong.
1800 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
1801 DestType,
1802 true,
1803 FoundOverload);
1804 if (!Fn) {
1805 msg = 0;
1806 return TC_Failed;
1807 }
1808
1809 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn);
1810 if (!SrcExpr.isUsable()) {
1811 msg = 0;
1812 return TC_Failed;
1813 }
1814 }
1815
1816 Self.BuildBasePathArray(Paths, BasePath);
1817 Kind = CK_DerivedToBaseMemberPointer;
1818 return TC_Success;
1819 }
1820
1821 /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1822 /// is valid:
1823 ///
1824 /// An expression e can be explicitly converted to a type T using a
1825 /// @c static_cast if the declaration "T t(e);" is well-formed [...].
1826 TryCastResult
TryStaticImplicitCast(Sema & Self,ExprResult & SrcExpr,QualType DestType,Sema::CheckedConversionKind CCK,SourceRange OpRange,unsigned & msg,CastKind & Kind,bool ListInitialization)1827 TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType,
1828 Sema::CheckedConversionKind CCK,
1829 SourceRange OpRange, unsigned &msg,
1830 CastKind &Kind, bool ListInitialization) {
1831 if (DestType->isRecordType()) {
1832 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1833 diag::err_bad_cast_incomplete) ||
1834 Self.RequireNonAbstractType(OpRange.getBegin(), DestType,
1835 diag::err_allocation_of_abstract_type)) {
1836 msg = 0;
1837 return TC_Failed;
1838 }
1839 }
1840
1841 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType);
1842 InitializationKind InitKind
1843 = (CCK == Sema::CCK_CStyleCast)
1844 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange,
1845 ListInitialization)
1846 : (CCK == Sema::CCK_FunctionalCast)
1847 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization)
1848 : InitializationKind::CreateCast(OpRange);
1849 Expr *SrcExprRaw = SrcExpr.get();
1850 // FIXME: Per DR242, we should check for an implicit conversion sequence
1851 // or for a constructor that could be invoked by direct-initialization
1852 // here, not for an initialization sequence.
1853 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1854
1855 // At this point of CheckStaticCast, if the destination is a reference,
1856 // or the expression is an overload expression this has to work.
1857 // There is no other way that works.
1858 // On the other hand, if we're checking a C-style cast, we've still got
1859 // the reinterpret_cast way.
1860 bool CStyle
1861 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1862 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1863 return TC_NotApplicable;
1864
1865 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw);
1866 if (Result.isInvalid()) {
1867 msg = 0;
1868 return TC_Failed;
1869 }
1870
1871 if (InitSeq.isConstructorInitialization())
1872 Kind = CK_ConstructorConversion;
1873 else
1874 Kind = CK_NoOp;
1875
1876 SrcExpr = Result;
1877 return TC_Success;
1878 }
1879
1880 /// TryConstCast - See if a const_cast from source to destination is allowed,
1881 /// and perform it if it is.
TryConstCast(Sema & Self,ExprResult & SrcExpr,QualType DestType,bool CStyle,unsigned & msg)1882 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1883 QualType DestType, bool CStyle,
1884 unsigned &msg) {
1885 DestType = Self.Context.getCanonicalType(DestType);
1886 QualType SrcType = SrcExpr.get()->getType();
1887 bool NeedToMaterializeTemporary = false;
1888
1889 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1890 // C++11 5.2.11p4:
1891 // if a pointer to T1 can be explicitly converted to the type "pointer to
1892 // T2" using a const_cast, then the following conversions can also be
1893 // made:
1894 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1895 // type T2 using the cast const_cast<T2&>;
1896 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1897 // type T2 using the cast const_cast<T2&&>; and
1898 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1899 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1900
1901 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1902 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1903 // is C-style, static_cast might find a way, so we simply suggest a
1904 // message and tell the parent to keep searching.
1905 msg = diag::err_bad_cxx_cast_rvalue;
1906 return TC_NotApplicable;
1907 }
1908
1909 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isPRValue()) {
1910 if (!SrcType->isRecordType()) {
1911 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1912 // this is C-style, static_cast can do this.
1913 msg = diag::err_bad_cxx_cast_rvalue;
1914 return TC_NotApplicable;
1915 }
1916
1917 // Materialize the class prvalue so that the const_cast can bind a
1918 // reference to it.
1919 NeedToMaterializeTemporary = true;
1920 }
1921
1922 // It's not completely clear under the standard whether we can
1923 // const_cast bit-field gl-values. Doing so would not be
1924 // intrinsically complicated, but for now, we say no for
1925 // consistency with other compilers and await the word of the
1926 // committee.
1927 if (SrcExpr.get()->refersToBitField()) {
1928 msg = diag::err_bad_cxx_cast_bitfield;
1929 return TC_NotApplicable;
1930 }
1931
1932 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1933 SrcType = Self.Context.getPointerType(SrcType);
1934 }
1935
1936 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
1937 // the rules for const_cast are the same as those used for pointers.
1938
1939 if (!DestType->isPointerType() &&
1940 !DestType->isMemberPointerType() &&
1941 !DestType->isObjCObjectPointerType()) {
1942 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
1943 // was a reference type, we converted it to a pointer above.
1944 // The status of rvalue references isn't entirely clear, but it looks like
1945 // conversion to them is simply invalid.
1946 // C++ 5.2.11p3: For two pointer types [...]
1947 if (!CStyle)
1948 msg = diag::err_bad_const_cast_dest;
1949 return TC_NotApplicable;
1950 }
1951 if (DestType->isFunctionPointerType() ||
1952 DestType->isMemberFunctionPointerType()) {
1953 // Cannot cast direct function pointers.
1954 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
1955 // T is the ultimate pointee of source and target type.
1956 if (!CStyle)
1957 msg = diag::err_bad_const_cast_dest;
1958 return TC_NotApplicable;
1959 }
1960
1961 // C++ [expr.const.cast]p3:
1962 // "For two similar types T1 and T2, [...]"
1963 //
1964 // We only allow a const_cast to change cvr-qualifiers, not other kinds of
1965 // type qualifiers. (Likewise, we ignore other changes when determining
1966 // whether a cast casts away constness.)
1967 if (!Self.Context.hasCvrSimilarType(SrcType, DestType))
1968 return TC_NotApplicable;
1969
1970 if (NeedToMaterializeTemporary)
1971 // This is a const_cast from a class prvalue to an rvalue reference type.
1972 // Materialize a temporary to store the result of the conversion.
1973 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcExpr.get()->getType(),
1974 SrcExpr.get(),
1975 /*IsLValueReference*/ false);
1976
1977 return TC_Success;
1978 }
1979
1980 // Checks for undefined behavior in reinterpret_cast.
1981 // The cases that is checked for is:
1982 // *reinterpret_cast<T*>(&a)
1983 // reinterpret_cast<T&>(a)
1984 // where accessing 'a' as type 'T' will result in undefined behavior.
CheckCompatibleReinterpretCast(QualType SrcType,QualType DestType,bool IsDereference,SourceRange Range)1985 void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
1986 bool IsDereference,
1987 SourceRange Range) {
1988 unsigned DiagID = IsDereference ?
1989 diag::warn_pointer_indirection_from_incompatible_type :
1990 diag::warn_undefined_reinterpret_cast;
1991
1992 if (Diags.isIgnored(DiagID, Range.getBegin()))
1993 return;
1994
1995 QualType SrcTy, DestTy;
1996 if (IsDereference) {
1997 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
1998 return;
1999 }
2000 SrcTy = SrcType->getPointeeType();
2001 DestTy = DestType->getPointeeType();
2002 } else {
2003 if (!DestType->getAs<ReferenceType>()) {
2004 return;
2005 }
2006 SrcTy = SrcType;
2007 DestTy = DestType->getPointeeType();
2008 }
2009
2010 // Cast is compatible if the types are the same.
2011 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) {
2012 return;
2013 }
2014 // or one of the types is a char or void type
2015 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
2016 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
2017 return;
2018 }
2019 // or one of the types is a tag type.
2020 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
2021 return;
2022 }
2023
2024 // FIXME: Scoped enums?
2025 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
2026 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
2027 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) {
2028 return;
2029 }
2030 }
2031
2032 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range;
2033 }
2034
DiagnoseCastOfObjCSEL(Sema & Self,const ExprResult & SrcExpr,QualType DestType)2035 static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
2036 QualType DestType) {
2037 QualType SrcType = SrcExpr.get()->getType();
2038 if (Self.Context.hasSameType(SrcType, DestType))
2039 return;
2040 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
2041 if (SrcPtrTy->isObjCSelType()) {
2042 QualType DT = DestType;
2043 if (isa<PointerType>(DestType))
2044 DT = DestType->getPointeeType();
2045 if (!DT.getUnqualifiedType()->isVoidType())
2046 Self.Diag(SrcExpr.get()->getExprLoc(),
2047 diag::warn_cast_pointer_from_sel)
2048 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2049 }
2050 }
2051
2052 /// Diagnose casts that change the calling convention of a pointer to a function
2053 /// defined in the current TU.
DiagnoseCallingConvCast(Sema & Self,const ExprResult & SrcExpr,QualType DstType,SourceRange OpRange)2054 static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr,
2055 QualType DstType, SourceRange OpRange) {
2056 // Check if this cast would change the calling convention of a function
2057 // pointer type.
2058 QualType SrcType = SrcExpr.get()->getType();
2059 if (Self.Context.hasSameType(SrcType, DstType) ||
2060 !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType())
2061 return;
2062 const auto *SrcFTy =
2063 SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
2064 const auto *DstFTy =
2065 DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
2066 CallingConv SrcCC = SrcFTy->getCallConv();
2067 CallingConv DstCC = DstFTy->getCallConv();
2068 if (SrcCC == DstCC)
2069 return;
2070
2071 // We have a calling convention cast. Check if the source is a pointer to a
2072 // known, specific function that has already been defined.
2073 Expr *Src = SrcExpr.get()->IgnoreParenImpCasts();
2074 if (auto *UO = dyn_cast<UnaryOperator>(Src))
2075 if (UO->getOpcode() == UO_AddrOf)
2076 Src = UO->getSubExpr()->IgnoreParenImpCasts();
2077 auto *DRE = dyn_cast<DeclRefExpr>(Src);
2078 if (!DRE)
2079 return;
2080 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
2081 if (!FD)
2082 return;
2083
2084 // Only warn if we are casting from the default convention to a non-default
2085 // convention. This can happen when the programmer forgot to apply the calling
2086 // convention to the function declaration and then inserted this cast to
2087 // satisfy the type system.
2088 CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
2089 FD->isVariadic(), FD->isCXXInstanceMember());
2090 if (DstCC == DefaultCC || SrcCC != DefaultCC)
2091 return;
2092
2093 // Diagnose this cast, as it is probably bad.
2094 StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC);
2095 StringRef DstCCName = FunctionType::getNameForCallConv(DstCC);
2096 Self.Diag(OpRange.getBegin(), diag::warn_cast_calling_conv)
2097 << SrcCCName << DstCCName << OpRange;
2098
2099 // The checks above are cheaper than checking if the diagnostic is enabled.
2100 // However, it's worth checking if the warning is enabled before we construct
2101 // a fixit.
2102 if (Self.Diags.isIgnored(diag::warn_cast_calling_conv, OpRange.getBegin()))
2103 return;
2104
2105 // Try to suggest a fixit to change the calling convention of the function
2106 // whose address was taken. Try to use the latest macro for the convention.
2107 // For example, users probably want to write "WINAPI" instead of "__stdcall"
2108 // to match the Windows header declarations.
2109 SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc();
2110 Preprocessor &PP = Self.getPreprocessor();
2111 SmallVector<TokenValue, 6> AttrTokens;
2112 SmallString<64> CCAttrText;
2113 llvm::raw_svector_ostream OS(CCAttrText);
2114 if (Self.getLangOpts().MicrosoftExt) {
2115 // __stdcall or __vectorcall
2116 OS << "__" << DstCCName;
2117 IdentifierInfo *II = PP.getIdentifierInfo(OS.str());
2118 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
2119 ? TokenValue(II->getTokenID())
2120 : TokenValue(II));
2121 } else {
2122 // __attribute__((stdcall)) or __attribute__((vectorcall))
2123 OS << "__attribute__((" << DstCCName << "))";
2124 AttrTokens.push_back(tok::kw___attribute);
2125 AttrTokens.push_back(tok::l_paren);
2126 AttrTokens.push_back(tok::l_paren);
2127 IdentifierInfo *II = PP.getIdentifierInfo(DstCCName);
2128 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
2129 ? TokenValue(II->getTokenID())
2130 : TokenValue(II));
2131 AttrTokens.push_back(tok::r_paren);
2132 AttrTokens.push_back(tok::r_paren);
2133 }
2134 StringRef AttrSpelling = PP.getLastMacroWithSpelling(NameLoc, AttrTokens);
2135 if (!AttrSpelling.empty())
2136 CCAttrText = AttrSpelling;
2137 OS << ' ';
2138 Self.Diag(NameLoc, diag::note_change_calling_conv_fixit)
2139 << FD << DstCCName << FixItHint::CreateInsertion(NameLoc, CCAttrText);
2140 }
2141
checkIntToPointerCast(bool CStyle,const SourceRange & OpRange,const Expr * SrcExpr,QualType DestType,Sema & Self)2142 static void checkIntToPointerCast(bool CStyle, const SourceRange &OpRange,
2143 const Expr *SrcExpr, QualType DestType,
2144 Sema &Self) {
2145 QualType SrcType = SrcExpr->getType();
2146
2147 // Not warning on reinterpret_cast, boolean, constant expressions, etc
2148 // are not explicit design choices, but consistent with GCC's behavior.
2149 // Feel free to modify them if you've reason/evidence for an alternative.
2150 if (CStyle && SrcType->isIntegralType(Self.Context)
2151 && !SrcType->isBooleanType()
2152 && !SrcType->isEnumeralType()
2153 && !SrcExpr->isIntegerConstantExpr(Self.Context)
2154 && Self.Context.getTypeSize(DestType) >
2155 Self.Context.getTypeSize(SrcType)) {
2156 // Separate between casts to void* and non-void* pointers.
2157 // Some APIs use (abuse) void* for something like a user context,
2158 // and often that value is an integer even if it isn't a pointer itself.
2159 // Having a separate warning flag allows users to control the warning
2160 // for their workflow.
2161 unsigned Diag = DestType->isVoidPointerType() ?
2162 diag::warn_int_to_void_pointer_cast
2163 : diag::warn_int_to_pointer_cast;
2164 Self.Diag(OpRange.getBegin(), Diag) << SrcType << DestType << OpRange;
2165 }
2166 }
2167
fixOverloadedReinterpretCastExpr(Sema & Self,QualType DestType,ExprResult & Result)2168 static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
2169 ExprResult &Result) {
2170 // We can only fix an overloaded reinterpret_cast if
2171 // - it is a template with explicit arguments that resolves to an lvalue
2172 // unambiguously, or
2173 // - it is the only function in an overload set that may have its address
2174 // taken.
2175
2176 Expr *E = Result.get();
2177 // TODO: what if this fails because of DiagnoseUseOfDecl or something
2178 // like it?
2179 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2180 Result,
2181 Expr::getValueKindForType(DestType) ==
2182 VK_PRValue // Convert Fun to Ptr
2183 ) &&
2184 Result.isUsable())
2185 return true;
2186
2187 // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization
2188 // preserves Result.
2189 Result = E;
2190 if (!Self.resolveAndFixAddressOfSingleOverloadCandidate(
2191 Result, /*DoFunctionPointerConversion=*/true))
2192 return false;
2193 return Result.isUsable();
2194 }
2195
TryReinterpretCast(Sema & Self,ExprResult & SrcExpr,QualType DestType,bool CStyle,SourceRange OpRange,unsigned & msg,CastKind & Kind)2196 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
2197 QualType DestType, bool CStyle,
2198 SourceRange OpRange,
2199 unsigned &msg,
2200 CastKind &Kind) {
2201 bool IsLValueCast = false;
2202
2203 DestType = Self.Context.getCanonicalType(DestType);
2204 QualType SrcType = SrcExpr.get()->getType();
2205
2206 // Is the source an overloaded name? (i.e. &foo)
2207 // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
2208 if (SrcType == Self.Context.OverloadTy) {
2209 ExprResult FixedExpr = SrcExpr;
2210 if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr))
2211 return TC_NotApplicable;
2212
2213 assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
2214 SrcExpr = FixedExpr;
2215 SrcType = SrcExpr.get()->getType();
2216 }
2217
2218 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
2219 if (!SrcExpr.get()->isGLValue()) {
2220 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
2221 // similar comment in const_cast.
2222 msg = diag::err_bad_cxx_cast_rvalue;
2223 return TC_NotApplicable;
2224 }
2225
2226 if (!CStyle) {
2227 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
2228 /*IsDereference=*/false, OpRange);
2229 }
2230
2231 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
2232 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
2233 // built-in & and * operators.
2234
2235 const char *inappropriate = nullptr;
2236 switch (SrcExpr.get()->getObjectKind()) {
2237 case OK_Ordinary:
2238 break;
2239 case OK_BitField:
2240 msg = diag::err_bad_cxx_cast_bitfield;
2241 return TC_NotApplicable;
2242 // FIXME: Use a specific diagnostic for the rest of these cases.
2243 case OK_VectorComponent: inappropriate = "vector element"; break;
2244 case OK_MatrixComponent:
2245 inappropriate = "matrix element";
2246 break;
2247 case OK_ObjCProperty: inappropriate = "property expression"; break;
2248 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
2249 break;
2250 }
2251 if (inappropriate) {
2252 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference)
2253 << inappropriate << DestType
2254 << OpRange << SrcExpr.get()->getSourceRange();
2255 msg = 0; SrcExpr = ExprError();
2256 return TC_NotApplicable;
2257 }
2258
2259 // This code does this transformation for the checked types.
2260 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
2261 SrcType = Self.Context.getPointerType(SrcType);
2262
2263 IsLValueCast = true;
2264 }
2265
2266 // Canonicalize source for comparison.
2267 SrcType = Self.Context.getCanonicalType(SrcType);
2268
2269 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
2270 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
2271 if (DestMemPtr && SrcMemPtr) {
2272 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
2273 // can be explicitly converted to an rvalue of type "pointer to member
2274 // of Y of type T2" if T1 and T2 are both function types or both object
2275 // types.
2276 if (DestMemPtr->isMemberFunctionPointer() !=
2277 SrcMemPtr->isMemberFunctionPointer())
2278 return TC_NotApplicable;
2279
2280 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2281 // We need to determine the inheritance model that the class will use if
2282 // haven't yet.
2283 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
2284 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
2285 }
2286
2287 // Don't allow casting between member pointers of different sizes.
2288 if (Self.Context.getTypeSize(DestMemPtr) !=
2289 Self.Context.getTypeSize(SrcMemPtr)) {
2290 msg = diag::err_bad_cxx_cast_member_pointer_size;
2291 return TC_Failed;
2292 }
2293
2294 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
2295 // constness.
2296 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
2297 // we accept it.
2298 if (auto CACK =
2299 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2300 /*CheckObjCLifetime=*/CStyle))
2301 return getCastAwayConstnessCastKind(CACK, msg);
2302
2303 // A valid member pointer cast.
2304 assert(!IsLValueCast);
2305 Kind = CK_ReinterpretMemberPointer;
2306 return TC_Success;
2307 }
2308
2309 // See below for the enumeral issue.
2310 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) {
2311 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
2312 // type large enough to hold it. A value of std::nullptr_t can be
2313 // converted to an integral type; the conversion has the same meaning
2314 // and validity as a conversion of (void*)0 to the integral type.
2315 if (Self.Context.getTypeSize(SrcType) >
2316 Self.Context.getTypeSize(DestType)) {
2317 msg = diag::err_bad_reinterpret_cast_small_int;
2318 return TC_Failed;
2319 }
2320 Kind = CK_PointerToIntegral;
2321 return TC_Success;
2322 }
2323
2324 // Allow reinterpret_casts between vectors of the same size and
2325 // between vectors and integers of the same size.
2326 bool destIsVector = DestType->isVectorType();
2327 bool srcIsVector = SrcType->isVectorType();
2328 if (srcIsVector || destIsVector) {
2329 // Allow bitcasting between SVE VLATs and VLSTs, and vice-versa.
2330 if (Self.isValidSveBitcast(SrcType, DestType)) {
2331 Kind = CK_BitCast;
2332 return TC_Success;
2333 }
2334
2335 // The non-vector type, if any, must have integral type. This is
2336 // the same rule that C vector casts use; note, however, that enum
2337 // types are not integral in C++.
2338 if ((!destIsVector && !DestType->isIntegralType(Self.Context)) ||
2339 (!srcIsVector && !SrcType->isIntegralType(Self.Context)))
2340 return TC_NotApplicable;
2341
2342 // The size we want to consider is eltCount * eltSize.
2343 // That's exactly what the lax-conversion rules will check.
2344 if (Self.areLaxCompatibleVectorTypes(SrcType, DestType)) {
2345 Kind = CK_BitCast;
2346 return TC_Success;
2347 }
2348
2349 if (Self.LangOpts.OpenCL && !CStyle) {
2350 if (DestType->isExtVectorType() || SrcType->isExtVectorType()) {
2351 // FIXME: Allow for reinterpret cast between 3 and 4 element vectors
2352 if (Self.areVectorTypesSameSize(SrcType, DestType)) {
2353 Kind = CK_BitCast;
2354 return TC_Success;
2355 }
2356 }
2357 }
2358
2359 // Otherwise, pick a reasonable diagnostic.
2360 if (!destIsVector)
2361 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
2362 else if (!srcIsVector)
2363 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
2364 else
2365 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
2366
2367 return TC_Failed;
2368 }
2369
2370 if (SrcType == DestType) {
2371 // C++ 5.2.10p2 has a note that mentions that, subject to all other
2372 // restrictions, a cast to the same type is allowed so long as it does not
2373 // cast away constness. In C++98, the intent was not entirely clear here,
2374 // since all other paragraphs explicitly forbid casts to the same type.
2375 // C++11 clarifies this case with p2.
2376 //
2377 // The only allowed types are: integral, enumeration, pointer, or
2378 // pointer-to-member types. We also won't restrict Obj-C pointers either.
2379 Kind = CK_NoOp;
2380 TryCastResult Result = TC_NotApplicable;
2381 if (SrcType->isIntegralOrEnumerationType() ||
2382 SrcType->isAnyPointerType() ||
2383 SrcType->isMemberPointerType() ||
2384 SrcType->isBlockPointerType()) {
2385 Result = TC_Success;
2386 }
2387 return Result;
2388 }
2389
2390 bool destIsPtr = DestType->isAnyPointerType() ||
2391 DestType->isBlockPointerType();
2392 bool srcIsPtr = SrcType->isAnyPointerType() ||
2393 SrcType->isBlockPointerType();
2394 if (!destIsPtr && !srcIsPtr) {
2395 // Except for std::nullptr_t->integer and lvalue->reference, which are
2396 // handled above, at least one of the two arguments must be a pointer.
2397 return TC_NotApplicable;
2398 }
2399
2400 if (DestType->isIntegralType(Self.Context)) {
2401 assert(srcIsPtr && "One type must be a pointer");
2402 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
2403 // type large enough to hold it; except in Microsoft mode, where the
2404 // integral type size doesn't matter (except we don't allow bool).
2405 if ((Self.Context.getTypeSize(SrcType) >
2406 Self.Context.getTypeSize(DestType))) {
2407 bool MicrosoftException =
2408 Self.getLangOpts().MicrosoftExt && !DestType->isBooleanType();
2409 if (MicrosoftException) {
2410 unsigned Diag = SrcType->isVoidPointerType()
2411 ? diag::warn_void_pointer_to_int_cast
2412 : diag::warn_pointer_to_int_cast;
2413 Self.Diag(OpRange.getBegin(), Diag) << SrcType << DestType << OpRange;
2414 } else {
2415 msg = diag::err_bad_reinterpret_cast_small_int;
2416 return TC_Failed;
2417 }
2418 }
2419 Kind = CK_PointerToIntegral;
2420 return TC_Success;
2421 }
2422
2423 if (SrcType->isIntegralOrEnumerationType()) {
2424 assert(destIsPtr && "One type must be a pointer");
2425 checkIntToPointerCast(CStyle, OpRange, SrcExpr.get(), DestType, Self);
2426 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
2427 // converted to a pointer.
2428 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
2429 // necessarily converted to a null pointer value.]
2430 Kind = CK_IntegralToPointer;
2431 return TC_Success;
2432 }
2433
2434 if (!destIsPtr || !srcIsPtr) {
2435 // With the valid non-pointer conversions out of the way, we can be even
2436 // more stringent.
2437 return TC_NotApplicable;
2438 }
2439
2440 // Cannot convert between block pointers and Objective-C object pointers.
2441 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
2442 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
2443 return TC_NotApplicable;
2444
2445 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
2446 // The C-style cast operator can.
2447 TryCastResult SuccessResult = TC_Success;
2448 if (auto CACK =
2449 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2450 /*CheckObjCLifetime=*/CStyle))
2451 SuccessResult = getCastAwayConstnessCastKind(CACK, msg);
2452
2453 if (IsAddressSpaceConversion(SrcType, DestType)) {
2454 Kind = CK_AddressSpaceConversion;
2455 assert(SrcType->isPointerType() && DestType->isPointerType());
2456 if (!CStyle &&
2457 !DestType->getPointeeType().getQualifiers().isAddressSpaceSupersetOf(
2458 SrcType->getPointeeType().getQualifiers())) {
2459 SuccessResult = TC_Failed;
2460 }
2461 } else if (IsLValueCast) {
2462 Kind = CK_LValueBitCast;
2463 } else if (DestType->isObjCObjectPointerType()) {
2464 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
2465 } else if (DestType->isBlockPointerType()) {
2466 if (!SrcType->isBlockPointerType()) {
2467 Kind = CK_AnyPointerToBlockPointerCast;
2468 } else {
2469 Kind = CK_BitCast;
2470 }
2471 } else {
2472 Kind = CK_BitCast;
2473 }
2474
2475 // Any pointer can be cast to an Objective-C pointer type with a C-style
2476 // cast.
2477 if (CStyle && DestType->isObjCObjectPointerType()) {
2478 return SuccessResult;
2479 }
2480 if (CStyle)
2481 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2482
2483 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2484
2485 // Not casting away constness, so the only remaining check is for compatible
2486 // pointer categories.
2487
2488 if (SrcType->isFunctionPointerType()) {
2489 if (DestType->isFunctionPointerType()) {
2490 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
2491 // a pointer to a function of a different type.
2492 return SuccessResult;
2493 }
2494
2495 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
2496 // an object type or vice versa is conditionally-supported.
2497 // Compilers support it in C++03 too, though, because it's necessary for
2498 // casting the return value of dlsym() and GetProcAddress().
2499 // FIXME: Conditionally-supported behavior should be configurable in the
2500 // TargetInfo or similar.
2501 Self.Diag(OpRange.getBegin(),
2502 Self.getLangOpts().CPlusPlus11 ?
2503 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2504 << OpRange;
2505 return SuccessResult;
2506 }
2507
2508 if (DestType->isFunctionPointerType()) {
2509 // See above.
2510 Self.Diag(OpRange.getBegin(),
2511 Self.getLangOpts().CPlusPlus11 ?
2512 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2513 << OpRange;
2514 return SuccessResult;
2515 }
2516
2517 // Diagnose address space conversion in nested pointers.
2518 QualType DestPtee = DestType->getPointeeType().isNull()
2519 ? DestType->getPointeeType()
2520 : DestType->getPointeeType()->getPointeeType();
2521 QualType SrcPtee = SrcType->getPointeeType().isNull()
2522 ? SrcType->getPointeeType()
2523 : SrcType->getPointeeType()->getPointeeType();
2524 while (!DestPtee.isNull() && !SrcPtee.isNull()) {
2525 if (DestPtee.getAddressSpace() != SrcPtee.getAddressSpace()) {
2526 Self.Diag(OpRange.getBegin(),
2527 diag::warn_bad_cxx_cast_nested_pointer_addr_space)
2528 << CStyle << SrcType << DestType << SrcExpr.get()->getSourceRange();
2529 break;
2530 }
2531 DestPtee = DestPtee->getPointeeType();
2532 SrcPtee = SrcPtee->getPointeeType();
2533 }
2534
2535 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
2536 // a pointer to an object of different type.
2537 // Void pointers are not specified, but supported by every compiler out there.
2538 // So we finish by allowing everything that remains - it's got to be two
2539 // object pointers.
2540 return SuccessResult;
2541 }
2542
TryAddressSpaceCast(Sema & Self,ExprResult & SrcExpr,QualType DestType,bool CStyle,unsigned & msg,CastKind & Kind)2543 static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
2544 QualType DestType, bool CStyle,
2545 unsigned &msg, CastKind &Kind) {
2546 if (!Self.getLangOpts().OpenCL)
2547 // FIXME: As compiler doesn't have any information about overlapping addr
2548 // spaces at the moment we have to be permissive here.
2549 return TC_NotApplicable;
2550 // Even though the logic below is general enough and can be applied to
2551 // non-OpenCL mode too, we fast-path above because no other languages
2552 // define overlapping address spaces currently.
2553 auto SrcType = SrcExpr.get()->getType();
2554 // FIXME: Should this be generalized to references? The reference parameter
2555 // however becomes a reference pointee type here and therefore rejected.
2556 // Perhaps this is the right behavior though according to C++.
2557 auto SrcPtrType = SrcType->getAs<PointerType>();
2558 if (!SrcPtrType)
2559 return TC_NotApplicable;
2560 auto DestPtrType = DestType->getAs<PointerType>();
2561 if (!DestPtrType)
2562 return TC_NotApplicable;
2563 auto SrcPointeeType = SrcPtrType->getPointeeType();
2564 auto DestPointeeType = DestPtrType->getPointeeType();
2565 if (!DestPointeeType.isAddressSpaceOverlapping(SrcPointeeType)) {
2566 msg = diag::err_bad_cxx_cast_addr_space_mismatch;
2567 return TC_Failed;
2568 }
2569 auto SrcPointeeTypeWithoutAS =
2570 Self.Context.removeAddrSpaceQualType(SrcPointeeType.getCanonicalType());
2571 auto DestPointeeTypeWithoutAS =
2572 Self.Context.removeAddrSpaceQualType(DestPointeeType.getCanonicalType());
2573 if (Self.Context.hasSameType(SrcPointeeTypeWithoutAS,
2574 DestPointeeTypeWithoutAS)) {
2575 Kind = SrcPointeeType.getAddressSpace() == DestPointeeType.getAddressSpace()
2576 ? CK_NoOp
2577 : CK_AddressSpaceConversion;
2578 return TC_Success;
2579 } else {
2580 return TC_NotApplicable;
2581 }
2582 }
2583
checkAddressSpaceCast(QualType SrcType,QualType DestType)2584 void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) {
2585 // In OpenCL only conversions between pointers to objects in overlapping
2586 // addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps
2587 // with any named one, except for constant.
2588
2589 // Converting the top level pointee addrspace is permitted for compatible
2590 // addrspaces (such as 'generic int *' to 'local int *' or vice versa), but
2591 // if any of the nested pointee addrspaces differ, we emit a warning
2592 // regardless of addrspace compatibility. This makes
2593 // local int ** p;
2594 // return (generic int **) p;
2595 // warn even though local -> generic is permitted.
2596 if (Self.getLangOpts().OpenCL) {
2597 const Type *DestPtr, *SrcPtr;
2598 bool Nested = false;
2599 unsigned DiagID = diag::err_typecheck_incompatible_address_space;
2600 DestPtr = Self.getASTContext().getCanonicalType(DestType.getTypePtr()),
2601 SrcPtr = Self.getASTContext().getCanonicalType(SrcType.getTypePtr());
2602
2603 while (isa<PointerType>(DestPtr) && isa<PointerType>(SrcPtr)) {
2604 const PointerType *DestPPtr = cast<PointerType>(DestPtr);
2605 const PointerType *SrcPPtr = cast<PointerType>(SrcPtr);
2606 QualType DestPPointee = DestPPtr->getPointeeType();
2607 QualType SrcPPointee = SrcPPtr->getPointeeType();
2608 if (Nested
2609 ? DestPPointee.getAddressSpace() != SrcPPointee.getAddressSpace()
2610 : !DestPPointee.isAddressSpaceOverlapping(SrcPPointee)) {
2611 Self.Diag(OpRange.getBegin(), DiagID)
2612 << SrcType << DestType << Sema::AA_Casting
2613 << SrcExpr.get()->getSourceRange();
2614 if (!Nested)
2615 SrcExpr = ExprError();
2616 return;
2617 }
2618
2619 DestPtr = DestPPtr->getPointeeType().getTypePtr();
2620 SrcPtr = SrcPPtr->getPointeeType().getTypePtr();
2621 Nested = true;
2622 DiagID = diag::ext_nested_pointer_qualifier_mismatch;
2623 }
2624 }
2625 }
2626
ShouldSplatAltivecScalarInCast(const VectorType * VecTy)2627 bool Sema::ShouldSplatAltivecScalarInCast(const VectorType *VecTy) {
2628 bool SrcCompatXL = this->getLangOpts().getAltivecSrcCompat() ==
2629 LangOptions::AltivecSrcCompatKind::XL;
2630 VectorType::VectorKind VKind = VecTy->getVectorKind();
2631
2632 if ((VKind == VectorType::AltiVecVector) ||
2633 (SrcCompatXL && ((VKind == VectorType::AltiVecBool) ||
2634 (VKind == VectorType::AltiVecPixel)))) {
2635 return true;
2636 }
2637 return false;
2638 }
2639
CheckCXXCStyleCast(bool FunctionalStyle,bool ListInitialization)2640 void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2641 bool ListInitialization) {
2642 assert(Self.getLangOpts().CPlusPlus);
2643
2644 // Handle placeholders.
2645 if (isPlaceholder()) {
2646 // C-style casts can resolve __unknown_any types.
2647 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2648 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2649 SrcExpr.get(), Kind,
2650 ValueKind, BasePath);
2651 return;
2652 }
2653
2654 checkNonOverloadPlaceholders();
2655 if (SrcExpr.isInvalid())
2656 return;
2657 }
2658
2659 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2660 // This test is outside everything else because it's the only case where
2661 // a non-lvalue-reference target type does not lead to decay.
2662 if (DestType->isVoidType()) {
2663 Kind = CK_ToVoid;
2664
2665 if (claimPlaceholder(BuiltinType::Overload)) {
2666 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2667 SrcExpr, /* Decay Function to ptr */ false,
2668 /* Complain */ true, DestRange, DestType,
2669 diag::err_bad_cstyle_cast_overload);
2670 if (SrcExpr.isInvalid())
2671 return;
2672 }
2673
2674 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2675 return;
2676 }
2677
2678 // If the type is dependent, we won't do any other semantic analysis now.
2679 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2680 SrcExpr.get()->isValueDependent()) {
2681 assert(Kind == CK_Dependent);
2682 return;
2683 }
2684
2685 if (ValueKind == VK_PRValue && !DestType->isRecordType() &&
2686 !isPlaceholder(BuiltinType::Overload)) {
2687 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2688 if (SrcExpr.isInvalid())
2689 return;
2690 }
2691
2692 // AltiVec vector initialization with a single literal.
2693 if (const VectorType *vecTy = DestType->getAs<VectorType>())
2694 if (Self.ShouldSplatAltivecScalarInCast(vecTy) &&
2695 (SrcExpr.get()->getType()->isIntegerType() ||
2696 SrcExpr.get()->getType()->isFloatingType())) {
2697 Kind = CK_VectorSplat;
2698 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2699 return;
2700 }
2701
2702 // C++ [expr.cast]p5: The conversions performed by
2703 // - a const_cast,
2704 // - a static_cast,
2705 // - a static_cast followed by a const_cast,
2706 // - a reinterpret_cast, or
2707 // - a reinterpret_cast followed by a const_cast,
2708 // can be performed using the cast notation of explicit type conversion.
2709 // [...] If a conversion can be interpreted in more than one of the ways
2710 // listed above, the interpretation that appears first in the list is used,
2711 // even if a cast resulting from that interpretation is ill-formed.
2712 // In plain language, this means trying a const_cast ...
2713 // Note that for address space we check compatibility after const_cast.
2714 unsigned msg = diag::err_bad_cxx_cast_generic;
2715 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2716 /*CStyle*/ true, msg);
2717 if (SrcExpr.isInvalid())
2718 return;
2719 if (isValidCast(tcr))
2720 Kind = CK_NoOp;
2721
2722 Sema::CheckedConversionKind CCK =
2723 FunctionalStyle ? Sema::CCK_FunctionalCast : Sema::CCK_CStyleCast;
2724 if (tcr == TC_NotApplicable) {
2725 tcr = TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ true, msg,
2726 Kind);
2727 if (SrcExpr.isInvalid())
2728 return;
2729
2730 if (tcr == TC_NotApplicable) {
2731 // ... or if that is not possible, a static_cast, ignoring const and
2732 // addr space, ...
2733 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, msg, Kind,
2734 BasePath, ListInitialization);
2735 if (SrcExpr.isInvalid())
2736 return;
2737
2738 if (tcr == TC_NotApplicable) {
2739 // ... and finally a reinterpret_cast, ignoring const and addr space.
2740 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/ true,
2741 OpRange, msg, Kind);
2742 if (SrcExpr.isInvalid())
2743 return;
2744 }
2745 }
2746 }
2747
2748 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
2749 isValidCast(tcr))
2750 checkObjCConversion(CCK);
2751
2752 if (tcr != TC_Success && msg != 0) {
2753 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2754 DeclAccessPair Found;
2755 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
2756 DestType,
2757 /*Complain*/ true,
2758 Found);
2759 if (Fn) {
2760 // If DestType is a function type (not to be confused with the function
2761 // pointer type), it will be possible to resolve the function address,
2762 // but the type cast should be considered as failure.
2763 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression;
2764 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload)
2765 << OE->getName() << DestType << OpRange
2766 << OE->getQualifierLoc().getSourceRange();
2767 Self.NoteAllOverloadCandidates(SrcExpr.get());
2768 }
2769 } else {
2770 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle),
2771 OpRange, SrcExpr.get(), DestType, ListInitialization);
2772 }
2773 }
2774
2775 if (isValidCast(tcr)) {
2776 if (Kind == CK_BitCast)
2777 checkCastAlign();
2778
2779 if (!checkCastFunctionType(Self, SrcExpr, DestType))
2780 Self.Diag(OpRange.getBegin(), diag::warn_cast_function_type)
2781 << SrcExpr.get()->getType() << DestType << OpRange;
2782
2783 } else {
2784 SrcExpr = ExprError();
2785 }
2786 }
2787
2788 /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2789 /// non-matching type. Such as enum function call to int, int call to
2790 /// pointer; etc. Cast to 'void' is an exception.
DiagnoseBadFunctionCast(Sema & Self,const ExprResult & SrcExpr,QualType DestType)2791 static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2792 QualType DestType) {
2793 if (Self.Diags.isIgnored(diag::warn_bad_function_cast,
2794 SrcExpr.get()->getExprLoc()))
2795 return;
2796
2797 if (!isa<CallExpr>(SrcExpr.get()))
2798 return;
2799
2800 QualType SrcType = SrcExpr.get()->getType();
2801 if (DestType.getUnqualifiedType()->isVoidType())
2802 return;
2803 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2804 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2805 return;
2806 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2807 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2808 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2809 return;
2810 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2811 return;
2812 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2813 return;
2814 if (SrcType->isComplexType() && DestType->isComplexType())
2815 return;
2816 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2817 return;
2818 if (SrcType->isFixedPointType() && DestType->isFixedPointType())
2819 return;
2820
2821 Self.Diag(SrcExpr.get()->getExprLoc(),
2822 diag::warn_bad_function_cast)
2823 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2824 }
2825
2826 /// Check the semantics of a C-style cast operation, in C.
CheckCStyleCast()2827 void CastOperation::CheckCStyleCast() {
2828 assert(!Self.getLangOpts().CPlusPlus);
2829
2830 // C-style casts can resolve __unknown_any types.
2831 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2832 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2833 SrcExpr.get(), Kind,
2834 ValueKind, BasePath);
2835 return;
2836 }
2837
2838 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
2839 // type needs to be scalar.
2840 if (DestType->isVoidType()) {
2841 // We don't necessarily do lvalue-to-rvalue conversions on this.
2842 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2843 if (SrcExpr.isInvalid())
2844 return;
2845
2846 // Cast to void allows any expr type.
2847 Kind = CK_ToVoid;
2848 return;
2849 }
2850
2851 // If the type is dependent, we won't do any other semantic analysis now.
2852 if (Self.getASTContext().isDependenceAllowed() &&
2853 (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2854 SrcExpr.get()->isValueDependent())) {
2855 assert((DestType->containsErrors() || SrcExpr.get()->containsErrors() ||
2856 SrcExpr.get()->containsErrors()) &&
2857 "should only occur in error-recovery path.");
2858 assert(Kind == CK_Dependent);
2859 return;
2860 }
2861
2862 // Overloads are allowed with C extensions, so we need to support them.
2863 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2864 DeclAccessPair DAP;
2865 if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction(
2866 SrcExpr.get(), DestType, /*Complain=*/true, DAP))
2867 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr.get(), DAP, FD);
2868 else
2869 return;
2870 assert(SrcExpr.isUsable());
2871 }
2872 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2873 if (SrcExpr.isInvalid())
2874 return;
2875 QualType SrcType = SrcExpr.get()->getType();
2876
2877 assert(!SrcType->isPlaceholderType());
2878
2879 checkAddressSpaceCast(SrcType, DestType);
2880 if (SrcExpr.isInvalid())
2881 return;
2882
2883 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2884 diag::err_typecheck_cast_to_incomplete)) {
2885 SrcExpr = ExprError();
2886 return;
2887 }
2888
2889 // Allow casting a sizeless built-in type to itself.
2890 if (DestType->isSizelessBuiltinType() &&
2891 Self.Context.hasSameUnqualifiedType(DestType, SrcType)) {
2892 Kind = CK_NoOp;
2893 return;
2894 }
2895
2896 // Allow bitcasting between compatible SVE vector types.
2897 if ((SrcType->isVectorType() || DestType->isVectorType()) &&
2898 Self.isValidSveBitcast(SrcType, DestType)) {
2899 Kind = CK_BitCast;
2900 return;
2901 }
2902
2903 if (!DestType->isScalarType() && !DestType->isVectorType() &&
2904 !DestType->isMatrixType()) {
2905 const RecordType *DestRecordTy = DestType->getAs<RecordType>();
2906
2907 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){
2908 // GCC struct/union extension: allow cast to self.
2909 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar)
2910 << DestType << SrcExpr.get()->getSourceRange();
2911 Kind = CK_NoOp;
2912 return;
2913 }
2914
2915 // GCC's cast to union extension.
2916 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) {
2917 RecordDecl *RD = DestRecordTy->getDecl();
2918 if (CastExpr::getTargetFieldForToUnionCast(RD, SrcType)) {
2919 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union)
2920 << SrcExpr.get()->getSourceRange();
2921 Kind = CK_ToUnion;
2922 return;
2923 } else {
2924 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type)
2925 << SrcType << SrcExpr.get()->getSourceRange();
2926 SrcExpr = ExprError();
2927 return;
2928 }
2929 }
2930
2931 // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type.
2932 if (Self.getLangOpts().OpenCL && DestType->isEventT()) {
2933 Expr::EvalResult Result;
2934 if (SrcExpr.get()->EvaluateAsInt(Result, Self.Context)) {
2935 llvm::APSInt CastInt = Result.Val.getInt();
2936 if (0 == CastInt) {
2937 Kind = CK_ZeroToOCLOpaqueType;
2938 return;
2939 }
2940 Self.Diag(OpRange.getBegin(),
2941 diag::err_opencl_cast_non_zero_to_event_t)
2942 << toString(CastInt, 10) << SrcExpr.get()->getSourceRange();
2943 SrcExpr = ExprError();
2944 return;
2945 }
2946 }
2947
2948 // Reject any other conversions to non-scalar types.
2949 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar)
2950 << DestType << SrcExpr.get()->getSourceRange();
2951 SrcExpr = ExprError();
2952 return;
2953 }
2954
2955 // The type we're casting to is known to be a scalar, a vector, or a matrix.
2956
2957 // Require the operand to be a scalar, a vector, or a matrix.
2958 if (!SrcType->isScalarType() && !SrcType->isVectorType() &&
2959 !SrcType->isMatrixType()) {
2960 Self.Diag(SrcExpr.get()->getExprLoc(),
2961 diag::err_typecheck_expect_scalar_operand)
2962 << SrcType << SrcExpr.get()->getSourceRange();
2963 SrcExpr = ExprError();
2964 return;
2965 }
2966
2967 if (DestType->isExtVectorType()) {
2968 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind);
2969 return;
2970 }
2971
2972 if (DestType->getAs<MatrixType>() || SrcType->getAs<MatrixType>()) {
2973 if (Self.CheckMatrixCast(OpRange, DestType, SrcType, Kind))
2974 SrcExpr = ExprError();
2975 return;
2976 }
2977
2978 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
2979 if (Self.ShouldSplatAltivecScalarInCast(DestVecTy) &&
2980 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
2981 Kind = CK_VectorSplat;
2982 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2983 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) {
2984 SrcExpr = ExprError();
2985 }
2986 return;
2987 }
2988
2989 if (SrcType->isVectorType()) {
2990 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind))
2991 SrcExpr = ExprError();
2992 return;
2993 }
2994
2995 // The source and target types are both scalars, i.e.
2996 // - arithmetic types (fundamental, enum, and complex)
2997 // - all kinds of pointers
2998 // Note that member pointers were filtered out with C++, above.
2999
3000 if (isa<ObjCSelectorExpr>(SrcExpr.get())) {
3001 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr);
3002 SrcExpr = ExprError();
3003 return;
3004 }
3005
3006 // Can't cast to or from bfloat
3007 if (DestType->isBFloat16Type() && !SrcType->isBFloat16Type()) {
3008 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_to_bfloat16)
3009 << SrcExpr.get()->getSourceRange();
3010 SrcExpr = ExprError();
3011 return;
3012 }
3013 if (SrcType->isBFloat16Type() && !DestType->isBFloat16Type()) {
3014 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_from_bfloat16)
3015 << SrcExpr.get()->getSourceRange();
3016 SrcExpr = ExprError();
3017 return;
3018 }
3019
3020 // If either type is a pointer, the other type has to be either an
3021 // integer or a pointer.
3022 if (!DestType->isArithmeticType()) {
3023 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) {
3024 Self.Diag(SrcExpr.get()->getExprLoc(),
3025 diag::err_cast_pointer_from_non_pointer_int)
3026 << SrcType << SrcExpr.get()->getSourceRange();
3027 SrcExpr = ExprError();
3028 return;
3029 }
3030 checkIntToPointerCast(/* CStyle */ true, OpRange, SrcExpr.get(), DestType,
3031 Self);
3032 } else if (!SrcType->isArithmeticType()) {
3033 if (!DestType->isIntegralType(Self.Context) &&
3034 DestType->isArithmeticType()) {
3035 Self.Diag(SrcExpr.get()->getBeginLoc(),
3036 diag::err_cast_pointer_to_non_pointer_int)
3037 << DestType << SrcExpr.get()->getSourceRange();
3038 SrcExpr = ExprError();
3039 return;
3040 }
3041
3042 if ((Self.Context.getTypeSize(SrcType) >
3043 Self.Context.getTypeSize(DestType)) &&
3044 !DestType->isBooleanType()) {
3045 // C 6.3.2.3p6: Any pointer type may be converted to an integer type.
3046 // Except as previously specified, the result is implementation-defined.
3047 // If the result cannot be represented in the integer type, the behavior
3048 // is undefined. The result need not be in the range of values of any
3049 // integer type.
3050 unsigned Diag;
3051 if (SrcType->isVoidPointerType())
3052 Diag = DestType->isEnumeralType() ? diag::warn_void_pointer_to_enum_cast
3053 : diag::warn_void_pointer_to_int_cast;
3054 else if (DestType->isEnumeralType())
3055 Diag = diag::warn_pointer_to_enum_cast;
3056 else
3057 Diag = diag::warn_pointer_to_int_cast;
3058 Self.Diag(OpRange.getBegin(), Diag) << SrcType << DestType << OpRange;
3059 }
3060 }
3061
3062 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().isAvailableOption(
3063 "cl_khr_fp16", Self.getLangOpts())) {
3064 if (DestType->isHalfType()) {
3065 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::err_opencl_cast_to_half)
3066 << DestType << SrcExpr.get()->getSourceRange();
3067 SrcExpr = ExprError();
3068 return;
3069 }
3070 }
3071
3072 // ARC imposes extra restrictions on casts.
3073 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) {
3074 checkObjCConversion(Sema::CCK_CStyleCast);
3075 if (SrcExpr.isInvalid())
3076 return;
3077
3078 const PointerType *CastPtr = DestType->getAs<PointerType>();
3079 if (Self.getLangOpts().ObjCAutoRefCount && CastPtr) {
3080 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
3081 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
3082 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
3083 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
3084 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
3085 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) {
3086 Self.Diag(SrcExpr.get()->getBeginLoc(),
3087 diag::err_typecheck_incompatible_ownership)
3088 << SrcType << DestType << Sema::AA_Casting
3089 << SrcExpr.get()->getSourceRange();
3090 return;
3091 }
3092 }
3093 }
3094 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) {
3095 Self.Diag(SrcExpr.get()->getBeginLoc(),
3096 diag::err_arc_convesion_of_weak_unavailable)
3097 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
3098 SrcExpr = ExprError();
3099 return;
3100 }
3101 }
3102
3103 if (!checkCastFunctionType(Self, SrcExpr, DestType))
3104 Self.Diag(OpRange.getBegin(), diag::warn_cast_function_type)
3105 << SrcType << DestType << OpRange;
3106
3107 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
3108 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
3109 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
3110 Kind = Self.PrepareScalarCast(SrcExpr, DestType);
3111 if (SrcExpr.isInvalid())
3112 return;
3113
3114 if (Kind == CK_BitCast)
3115 checkCastAlign();
3116 }
3117
CheckBuiltinBitCast()3118 void CastOperation::CheckBuiltinBitCast() {
3119 QualType SrcType = SrcExpr.get()->getType();
3120
3121 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
3122 diag::err_typecheck_cast_to_incomplete) ||
3123 Self.RequireCompleteType(OpRange.getBegin(), SrcType,
3124 diag::err_incomplete_type)) {
3125 SrcExpr = ExprError();
3126 return;
3127 }
3128
3129 if (SrcExpr.get()->isPRValue())
3130 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcType, SrcExpr.get(),
3131 /*IsLValueReference=*/false);
3132
3133 CharUnits DestSize = Self.Context.getTypeSizeInChars(DestType);
3134 CharUnits SourceSize = Self.Context.getTypeSizeInChars(SrcType);
3135 if (DestSize != SourceSize) {
3136 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_type_size_mismatch)
3137 << (int)SourceSize.getQuantity() << (int)DestSize.getQuantity();
3138 SrcExpr = ExprError();
3139 return;
3140 }
3141
3142 if (!DestType.isTriviallyCopyableType(Self.Context)) {
3143 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
3144 << 1;
3145 SrcExpr = ExprError();
3146 return;
3147 }
3148
3149 if (!SrcType.isTriviallyCopyableType(Self.Context)) {
3150 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
3151 << 0;
3152 SrcExpr = ExprError();
3153 return;
3154 }
3155
3156 Kind = CK_LValueToRValueBitCast;
3157 }
3158
3159 /// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
3160 /// const, volatile or both.
DiagnoseCastQual(Sema & Self,const ExprResult & SrcExpr,QualType DestType)3161 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
3162 QualType DestType) {
3163 if (SrcExpr.isInvalid())
3164 return;
3165
3166 QualType SrcType = SrcExpr.get()->getType();
3167 if (!((SrcType->isAnyPointerType() && DestType->isAnyPointerType()) ||
3168 DestType->isLValueReferenceType()))
3169 return;
3170
3171 QualType TheOffendingSrcType, TheOffendingDestType;
3172 Qualifiers CastAwayQualifiers;
3173 if (CastsAwayConstness(Self, SrcType, DestType, true, false,
3174 &TheOffendingSrcType, &TheOffendingDestType,
3175 &CastAwayQualifiers) !=
3176 CastAwayConstnessKind::CACK_Similar)
3177 return;
3178
3179 // FIXME: 'restrict' is not properly handled here.
3180 int qualifiers = -1;
3181 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
3182 qualifiers = 0;
3183 } else if (CastAwayQualifiers.hasConst()) {
3184 qualifiers = 1;
3185 } else if (CastAwayQualifiers.hasVolatile()) {
3186 qualifiers = 2;
3187 }
3188 // This is a variant of int **x; const int **y = (const int **)x;
3189 if (qualifiers == -1)
3190 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::warn_cast_qual2)
3191 << SrcType << DestType;
3192 else
3193 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::warn_cast_qual)
3194 << TheOffendingSrcType << TheOffendingDestType << qualifiers;
3195 }
3196
BuildCStyleCastExpr(SourceLocation LPLoc,TypeSourceInfo * CastTypeInfo,SourceLocation RPLoc,Expr * CastExpr)3197 ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
3198 TypeSourceInfo *CastTypeInfo,
3199 SourceLocation RPLoc,
3200 Expr *CastExpr) {
3201 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
3202 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
3203 Op.OpRange = SourceRange(LPLoc, CastExpr->getEndLoc());
3204
3205 if (getLangOpts().CPlusPlus) {
3206 Op.CheckCXXCStyleCast(/*FunctionalCast=*/ false,
3207 isa<InitListExpr>(CastExpr));
3208 } else {
3209 Op.CheckCStyleCast();
3210 }
3211
3212 if (Op.SrcExpr.isInvalid())
3213 return ExprError();
3214
3215 // -Wcast-qual
3216 DiagnoseCastQual(Op.Self, Op.SrcExpr, Op.DestType);
3217
3218 return Op.complete(CStyleCastExpr::Create(
3219 Context, Op.ResultType, Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
3220 &Op.BasePath, CurFPFeatureOverrides(), CastTypeInfo, LPLoc, RPLoc));
3221 }
3222
BuildCXXFunctionalCastExpr(TypeSourceInfo * CastTypeInfo,QualType Type,SourceLocation LPLoc,Expr * CastExpr,SourceLocation RPLoc)3223 ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
3224 QualType Type,
3225 SourceLocation LPLoc,
3226 Expr *CastExpr,
3227 SourceLocation RPLoc) {
3228 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
3229 CastOperation Op(*this, Type, CastExpr);
3230 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
3231 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getEndLoc());
3232
3233 Op.CheckCXXCStyleCast(/*FunctionalCast=*/true, /*ListInit=*/false);
3234 if (Op.SrcExpr.isInvalid())
3235 return ExprError();
3236
3237 auto *SubExpr = Op.SrcExpr.get();
3238 if (auto *BindExpr = dyn_cast<CXXBindTemporaryExpr>(SubExpr))
3239 SubExpr = BindExpr->getSubExpr();
3240 if (auto *ConstructExpr = dyn_cast<CXXConstructExpr>(SubExpr))
3241 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc));
3242
3243 return Op.complete(CXXFunctionalCastExpr::Create(
3244 Context, Op.ResultType, Op.ValueKind, CastTypeInfo, Op.Kind,
3245 Op.SrcExpr.get(), &Op.BasePath, CurFPFeatureOverrides(), LPLoc, RPLoc));
3246 }
3247