SemaCast.cpp revision 261991
1//===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for cast expressions, including 11// 1) C-style casts like '(int) x' 12// 2) C++ functional casts like 'int(x)' 13// 3) C++ named casts like 'static_cast<int>(x)' 14// 15//===----------------------------------------------------------------------===// 16 17#include "clang/Sema/SemaInternal.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/CXXInheritance.h" 20#include "clang/AST/ExprCXX.h" 21#include "clang/AST/ExprObjC.h" 22#include "clang/AST/RecordLayout.h" 23#include "clang/Basic/PartialDiagnostic.h" 24#include "clang/Sema/Initialization.h" 25#include "llvm/ADT/SmallVector.h" 26#include <set> 27using namespace clang; 28 29 30 31enum TryCastResult { 32 TC_NotApplicable, ///< The cast method is not applicable. 33 TC_Success, ///< The cast method is appropriate and successful. 34 TC_Failed ///< The cast method is appropriate, but failed. A 35 ///< diagnostic has been emitted. 36}; 37 38enum CastType { 39 CT_Const, ///< const_cast 40 CT_Static, ///< static_cast 41 CT_Reinterpret, ///< reinterpret_cast 42 CT_Dynamic, ///< dynamic_cast 43 CT_CStyle, ///< (Type)expr 44 CT_Functional ///< Type(expr) 45}; 46 47namespace { 48 struct CastOperation { 49 CastOperation(Sema &S, QualType destType, ExprResult src) 50 : Self(S), SrcExpr(src), DestType(destType), 51 ResultType(destType.getNonLValueExprType(S.Context)), 52 ValueKind(Expr::getValueKindForType(destType)), 53 Kind(CK_Dependent), IsARCUnbridgedCast(false) { 54 55 if (const BuiltinType *placeholder = 56 src.get()->getType()->getAsPlaceholderType()) { 57 PlaceholderKind = placeholder->getKind(); 58 } else { 59 PlaceholderKind = (BuiltinType::Kind) 0; 60 } 61 } 62 63 Sema &Self; 64 ExprResult SrcExpr; 65 QualType DestType; 66 QualType ResultType; 67 ExprValueKind ValueKind; 68 CastKind Kind; 69 BuiltinType::Kind PlaceholderKind; 70 CXXCastPath BasePath; 71 bool IsARCUnbridgedCast; 72 73 SourceRange OpRange; 74 SourceRange DestRange; 75 76 // Top-level semantics-checking routines. 77 void CheckConstCast(); 78 void CheckReinterpretCast(); 79 void CheckStaticCast(); 80 void CheckDynamicCast(); 81 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization); 82 void CheckCStyleCast(); 83 84 /// Complete an apparently-successful cast operation that yields 85 /// the given expression. 86 ExprResult complete(CastExpr *castExpr) { 87 // If this is an unbridged cast, wrap the result in an implicit 88 // cast that yields the unbridged-cast placeholder type. 89 if (IsARCUnbridgedCast) { 90 castExpr = ImplicitCastExpr::Create(Self.Context, 91 Self.Context.ARCUnbridgedCastTy, 92 CK_Dependent, castExpr, 0, 93 castExpr->getValueKind()); 94 } 95 return Self.Owned(castExpr); 96 } 97 98 // Internal convenience methods. 99 100 /// Try to handle the given placeholder expression kind. Return 101 /// true if the source expression has the appropriate placeholder 102 /// kind. A placeholder can only be claimed once. 103 bool claimPlaceholder(BuiltinType::Kind K) { 104 if (PlaceholderKind != K) return false; 105 106 PlaceholderKind = (BuiltinType::Kind) 0; 107 return true; 108 } 109 110 bool isPlaceholder() const { 111 return PlaceholderKind != 0; 112 } 113 bool isPlaceholder(BuiltinType::Kind K) const { 114 return PlaceholderKind == K; 115 } 116 117 void checkCastAlign() { 118 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange); 119 } 120 121 void checkObjCARCConversion(Sema::CheckedConversionKind CCK) { 122 assert(Self.getLangOpts().ObjCAutoRefCount); 123 124 Expr *src = SrcExpr.get(); 125 if (Self.CheckObjCARCConversion(OpRange, DestType, src, CCK) == 126 Sema::ACR_unbridged) 127 IsARCUnbridgedCast = true; 128 SrcExpr = src; 129 } 130 131 /// Check for and handle non-overload placeholder expressions. 132 void checkNonOverloadPlaceholders() { 133 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload)) 134 return; 135 136 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.take()); 137 if (SrcExpr.isInvalid()) 138 return; 139 PlaceholderKind = (BuiltinType::Kind) 0; 140 } 141 }; 142} 143 144static bool CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, 145 bool CheckCVR, bool CheckObjCLifetime); 146 147// The Try functions attempt a specific way of casting. If they succeed, they 148// return TC_Success. If their way of casting is not appropriate for the given 149// arguments, they return TC_NotApplicable and *may* set diag to a diagnostic 150// to emit if no other way succeeds. If their way of casting is appropriate but 151// fails, they return TC_Failed and *must* set diag; they can set it to 0 if 152// they emit a specialized diagnostic. 153// All diagnostics returned by these functions must expect the same three 154// arguments: 155// %0: Cast Type (a value from the CastType enumeration) 156// %1: Source Type 157// %2: Destination Type 158static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, 159 QualType DestType, bool CStyle, 160 CastKind &Kind, 161 CXXCastPath &BasePath, 162 unsigned &msg); 163static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, 164 QualType DestType, bool CStyle, 165 const SourceRange &OpRange, 166 unsigned &msg, 167 CastKind &Kind, 168 CXXCastPath &BasePath); 169static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType, 170 QualType DestType, bool CStyle, 171 const SourceRange &OpRange, 172 unsigned &msg, 173 CastKind &Kind, 174 CXXCastPath &BasePath); 175static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType, 176 CanQualType DestType, bool CStyle, 177 const SourceRange &OpRange, 178 QualType OrigSrcType, 179 QualType OrigDestType, unsigned &msg, 180 CastKind &Kind, 181 CXXCastPath &BasePath); 182static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, 183 QualType SrcType, 184 QualType DestType,bool CStyle, 185 const SourceRange &OpRange, 186 unsigned &msg, 187 CastKind &Kind, 188 CXXCastPath &BasePath); 189 190static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, 191 QualType DestType, 192 Sema::CheckedConversionKind CCK, 193 const SourceRange &OpRange, 194 unsigned &msg, CastKind &Kind, 195 bool ListInitialization); 196static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, 197 QualType DestType, 198 Sema::CheckedConversionKind CCK, 199 const SourceRange &OpRange, 200 unsigned &msg, CastKind &Kind, 201 CXXCastPath &BasePath, 202 bool ListInitialization); 203static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, 204 QualType DestType, bool CStyle, 205 unsigned &msg); 206static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 207 QualType DestType, bool CStyle, 208 const SourceRange &OpRange, 209 unsigned &msg, 210 CastKind &Kind); 211 212 213/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's. 214ExprResult 215Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 216 SourceLocation LAngleBracketLoc, Declarator &D, 217 SourceLocation RAngleBracketLoc, 218 SourceLocation LParenLoc, Expr *E, 219 SourceLocation RParenLoc) { 220 221 assert(!D.isInvalidType()); 222 223 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType()); 224 if (D.isInvalidType()) 225 return ExprError(); 226 227 if (getLangOpts().CPlusPlus) { 228 // Check that there are no default arguments (C++ only). 229 CheckExtraCXXDefaultArguments(D); 230 } 231 232 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E, 233 SourceRange(LAngleBracketLoc, RAngleBracketLoc), 234 SourceRange(LParenLoc, RParenLoc)); 235} 236 237ExprResult 238Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 239 TypeSourceInfo *DestTInfo, Expr *E, 240 SourceRange AngleBrackets, SourceRange Parens) { 241 ExprResult Ex = Owned(E); 242 QualType DestType = DestTInfo->getType(); 243 244 // If the type is dependent, we won't do the semantic analysis now. 245 // FIXME: should we check this in a more fine-grained manner? 246 bool TypeDependent = DestType->isDependentType() || 247 Ex.get()->isTypeDependent() || 248 Ex.get()->isValueDependent(); 249 250 CastOperation Op(*this, DestType, E); 251 Op.OpRange = SourceRange(OpLoc, Parens.getEnd()); 252 Op.DestRange = AngleBrackets; 253 254 switch (Kind) { 255 default: llvm_unreachable("Unknown C++ cast!"); 256 257 case tok::kw_const_cast: 258 if (!TypeDependent) { 259 Op.CheckConstCast(); 260 if (Op.SrcExpr.isInvalid()) 261 return ExprError(); 262 } 263 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType, 264 Op.ValueKind, Op.SrcExpr.take(), DestTInfo, 265 OpLoc, Parens.getEnd(), 266 AngleBrackets)); 267 268 case tok::kw_dynamic_cast: { 269 if (!TypeDependent) { 270 Op.CheckDynamicCast(); 271 if (Op.SrcExpr.isInvalid()) 272 return ExprError(); 273 } 274 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType, 275 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 276 &Op.BasePath, DestTInfo, 277 OpLoc, Parens.getEnd(), 278 AngleBrackets)); 279 } 280 case tok::kw_reinterpret_cast: { 281 if (!TypeDependent) { 282 Op.CheckReinterpretCast(); 283 if (Op.SrcExpr.isInvalid()) 284 return ExprError(); 285 } 286 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType, 287 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 288 0, DestTInfo, OpLoc, 289 Parens.getEnd(), 290 AngleBrackets)); 291 } 292 case tok::kw_static_cast: { 293 if (!TypeDependent) { 294 Op.CheckStaticCast(); 295 if (Op.SrcExpr.isInvalid()) 296 return ExprError(); 297 } 298 299 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType, 300 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 301 &Op.BasePath, DestTInfo, 302 OpLoc, Parens.getEnd(), 303 AngleBrackets)); 304 } 305 } 306} 307 308/// Try to diagnose a failed overloaded cast. Returns true if 309/// diagnostics were emitted. 310static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT, 311 SourceRange range, Expr *src, 312 QualType destType, 313 bool listInitialization) { 314 switch (CT) { 315 // These cast kinds don't consider user-defined conversions. 316 case CT_Const: 317 case CT_Reinterpret: 318 case CT_Dynamic: 319 return false; 320 321 // These do. 322 case CT_Static: 323 case CT_CStyle: 324 case CT_Functional: 325 break; 326 } 327 328 QualType srcType = src->getType(); 329 if (!destType->isRecordType() && !srcType->isRecordType()) 330 return false; 331 332 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType); 333 InitializationKind initKind 334 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(), 335 range, listInitialization) 336 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range, 337 listInitialization) 338 : InitializationKind::CreateCast(/*type range?*/ range); 339 InitializationSequence sequence(S, entity, initKind, src); 340 341 assert(sequence.Failed() && "initialization succeeded on second try?"); 342 switch (sequence.getFailureKind()) { 343 default: return false; 344 345 case InitializationSequence::FK_ConstructorOverloadFailed: 346 case InitializationSequence::FK_UserConversionOverloadFailed: 347 break; 348 } 349 350 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet(); 351 352 unsigned msg = 0; 353 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates; 354 355 switch (sequence.getFailedOverloadResult()) { 356 case OR_Success: llvm_unreachable("successful failed overload"); 357 case OR_No_Viable_Function: 358 if (candidates.empty()) 359 msg = diag::err_ovl_no_conversion_in_cast; 360 else 361 msg = diag::err_ovl_no_viable_conversion_in_cast; 362 howManyCandidates = OCD_AllCandidates; 363 break; 364 365 case OR_Ambiguous: 366 msg = diag::err_ovl_ambiguous_conversion_in_cast; 367 howManyCandidates = OCD_ViableCandidates; 368 break; 369 370 case OR_Deleted: 371 msg = diag::err_ovl_deleted_conversion_in_cast; 372 howManyCandidates = OCD_ViableCandidates; 373 break; 374 } 375 376 S.Diag(range.getBegin(), msg) 377 << CT << srcType << destType 378 << range << src->getSourceRange(); 379 380 candidates.NoteCandidates(S, howManyCandidates, src); 381 382 return true; 383} 384 385/// Diagnose a failed cast. 386static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType, 387 SourceRange opRange, Expr *src, QualType destType, 388 bool listInitialization) { 389 if (msg == diag::err_bad_cxx_cast_generic && 390 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType, 391 listInitialization)) 392 return; 393 394 S.Diag(opRange.getBegin(), msg) << castType 395 << src->getType() << destType << opRange << src->getSourceRange(); 396} 397 398/// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes, 399/// this removes one level of indirection from both types, provided that they're 400/// the same kind of pointer (plain or to-member). Unlike the Sema function, 401/// this one doesn't care if the two pointers-to-member don't point into the 402/// same class. This is because CastsAwayConstness doesn't care. 403static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) { 404 const PointerType *T1PtrType = T1->getAs<PointerType>(), 405 *T2PtrType = T2->getAs<PointerType>(); 406 if (T1PtrType && T2PtrType) { 407 T1 = T1PtrType->getPointeeType(); 408 T2 = T2PtrType->getPointeeType(); 409 return true; 410 } 411 const ObjCObjectPointerType *T1ObjCPtrType = 412 T1->getAs<ObjCObjectPointerType>(), 413 *T2ObjCPtrType = 414 T2->getAs<ObjCObjectPointerType>(); 415 if (T1ObjCPtrType) { 416 if (T2ObjCPtrType) { 417 T1 = T1ObjCPtrType->getPointeeType(); 418 T2 = T2ObjCPtrType->getPointeeType(); 419 return true; 420 } 421 else if (T2PtrType) { 422 T1 = T1ObjCPtrType->getPointeeType(); 423 T2 = T2PtrType->getPointeeType(); 424 return true; 425 } 426 } 427 else if (T2ObjCPtrType) { 428 if (T1PtrType) { 429 T2 = T2ObjCPtrType->getPointeeType(); 430 T1 = T1PtrType->getPointeeType(); 431 return true; 432 } 433 } 434 435 const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(), 436 *T2MPType = T2->getAs<MemberPointerType>(); 437 if (T1MPType && T2MPType) { 438 T1 = T1MPType->getPointeeType(); 439 T2 = T2MPType->getPointeeType(); 440 return true; 441 } 442 443 const BlockPointerType *T1BPType = T1->getAs<BlockPointerType>(), 444 *T2BPType = T2->getAs<BlockPointerType>(); 445 if (T1BPType && T2BPType) { 446 T1 = T1BPType->getPointeeType(); 447 T2 = T2BPType->getPointeeType(); 448 return true; 449 } 450 451 return false; 452} 453 454/// CastsAwayConstness - Check if the pointer conversion from SrcType to 455/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by 456/// the cast checkers. Both arguments must denote pointer (possibly to member) 457/// types. 458/// 459/// \param CheckCVR Whether to check for const/volatile/restrict qualifiers. 460/// 461/// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers. 462static bool 463CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, 464 bool CheckCVR, bool CheckObjCLifetime) { 465 // If the only checking we care about is for Objective-C lifetime qualifiers, 466 // and we're not in ARC mode, there's nothing to check. 467 if (!CheckCVR && CheckObjCLifetime && 468 !Self.Context.getLangOpts().ObjCAutoRefCount) 469 return false; 470 471 // Casting away constness is defined in C++ 5.2.11p8 with reference to 472 // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since 473 // the rules are non-trivial. So first we construct Tcv *...cv* as described 474 // in C++ 5.2.11p8. 475 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() || 476 SrcType->isBlockPointerType()) && 477 "Source type is not pointer or pointer to member."); 478 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() || 479 DestType->isBlockPointerType()) && 480 "Destination type is not pointer or pointer to member."); 481 482 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType), 483 UnwrappedDestType = Self.Context.getCanonicalType(DestType); 484 SmallVector<Qualifiers, 8> cv1, cv2; 485 486 // Find the qualifiers. We only care about cvr-qualifiers for the 487 // purpose of this check, because other qualifiers (address spaces, 488 // Objective-C GC, etc.) are part of the type's identity. 489 while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) { 490 // Determine the relevant qualifiers at this level. 491 Qualifiers SrcQuals, DestQuals; 492 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals); 493 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals); 494 495 Qualifiers RetainedSrcQuals, RetainedDestQuals; 496 if (CheckCVR) { 497 RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers()); 498 RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers()); 499 } 500 501 if (CheckObjCLifetime && 502 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals)) 503 return true; 504 505 cv1.push_back(RetainedSrcQuals); 506 cv2.push_back(RetainedDestQuals); 507 } 508 if (cv1.empty()) 509 return false; 510 511 // Construct void pointers with those qualifiers (in reverse order of 512 // unwrapping, of course). 513 QualType SrcConstruct = Self.Context.VoidTy; 514 QualType DestConstruct = Self.Context.VoidTy; 515 ASTContext &Context = Self.Context; 516 for (SmallVectorImpl<Qualifiers>::reverse_iterator i1 = cv1.rbegin(), 517 i2 = cv2.rbegin(); 518 i1 != cv1.rend(); ++i1, ++i2) { 519 SrcConstruct 520 = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1)); 521 DestConstruct 522 = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2)); 523 } 524 525 // Test if they're compatible. 526 bool ObjCLifetimeConversion; 527 return SrcConstruct != DestConstruct && 528 !Self.IsQualificationConversion(SrcConstruct, DestConstruct, false, 529 ObjCLifetimeConversion); 530} 531 532/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid. 533/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime- 534/// checked downcasts in class hierarchies. 535void CastOperation::CheckDynamicCast() { 536 if (ValueKind == VK_RValue) 537 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 538 else if (isPlaceholder()) 539 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.take()); 540 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 541 return; 542 543 QualType OrigSrcType = SrcExpr.get()->getType(); 544 QualType DestType = Self.Context.getCanonicalType(this->DestType); 545 546 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type, 547 // or "pointer to cv void". 548 549 QualType DestPointee; 550 const PointerType *DestPointer = DestType->getAs<PointerType>(); 551 const ReferenceType *DestReference = 0; 552 if (DestPointer) { 553 DestPointee = DestPointer->getPointeeType(); 554 } else if ((DestReference = DestType->getAs<ReferenceType>())) { 555 DestPointee = DestReference->getPointeeType(); 556 } else { 557 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr) 558 << this->DestType << DestRange; 559 SrcExpr = ExprError(); 560 return; 561 } 562 563 const RecordType *DestRecord = DestPointee->getAs<RecordType>(); 564 if (DestPointee->isVoidType()) { 565 assert(DestPointer && "Reference to void is not possible"); 566 } else if (DestRecord) { 567 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, 568 diag::err_bad_dynamic_cast_incomplete, 569 DestRange)) { 570 SrcExpr = ExprError(); 571 return; 572 } 573 } else { 574 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 575 << DestPointee.getUnqualifiedType() << DestRange; 576 SrcExpr = ExprError(); 577 return; 578 } 579 580 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to 581 // complete class type, [...]. If T is an lvalue reference type, v shall be 582 // an lvalue of a complete class type, [...]. If T is an rvalue reference 583 // type, v shall be an expression having a complete class type, [...] 584 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType); 585 QualType SrcPointee; 586 if (DestPointer) { 587 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 588 SrcPointee = SrcPointer->getPointeeType(); 589 } else { 590 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr) 591 << OrigSrcType << SrcExpr.get()->getSourceRange(); 592 SrcExpr = ExprError(); 593 return; 594 } 595 } else if (DestReference->isLValueReferenceType()) { 596 if (!SrcExpr.get()->isLValue()) { 597 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue) 598 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 599 } 600 SrcPointee = SrcType; 601 } else { 602 SrcPointee = SrcType; 603 } 604 605 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>(); 606 if (SrcRecord) { 607 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee, 608 diag::err_bad_dynamic_cast_incomplete, 609 SrcExpr.get())) { 610 SrcExpr = ExprError(); 611 return; 612 } 613 } else { 614 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 615 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 616 SrcExpr = ExprError(); 617 return; 618 } 619 620 assert((DestPointer || DestReference) && 621 "Bad destination non-ptr/ref slipped through."); 622 assert((DestRecord || DestPointee->isVoidType()) && 623 "Bad destination pointee slipped through."); 624 assert(SrcRecord && "Bad source pointee slipped through."); 625 626 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness. 627 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) { 628 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away) 629 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 630 SrcExpr = ExprError(); 631 return; 632 } 633 634 // C++ 5.2.7p3: If the type of v is the same as the required result type, 635 // [except for cv]. 636 if (DestRecord == SrcRecord) { 637 Kind = CK_NoOp; 638 return; 639 } 640 641 // C++ 5.2.7p5 642 // Upcasts are resolved statically. 643 if (DestRecord && Self.IsDerivedFrom(SrcPointee, DestPointee)) { 644 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee, 645 OpRange.getBegin(), OpRange, 646 &BasePath)) { 647 SrcExpr = ExprError(); 648 return; 649 } 650 651 Kind = CK_DerivedToBase; 652 653 // If we are casting to or through a virtual base class, we need a 654 // vtable. 655 if (Self.BasePathInvolvesVirtualBase(BasePath)) 656 Self.MarkVTableUsed(OpRange.getBegin(), 657 cast<CXXRecordDecl>(SrcRecord->getDecl())); 658 return; 659 } 660 661 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic]. 662 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition(); 663 assert(SrcDecl && "Definition missing"); 664 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) { 665 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic) 666 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 667 SrcExpr = ExprError(); 668 } 669 Self.MarkVTableUsed(OpRange.getBegin(), 670 cast<CXXRecordDecl>(SrcRecord->getDecl())); 671 672 // dynamic_cast is not available with -fno-rtti. 673 // As an exception, dynamic_cast to void* is available because it doesn't 674 // use RTTI. 675 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) { 676 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti); 677 SrcExpr = ExprError(); 678 return; 679 } 680 681 // Done. Everything else is run-time checks. 682 Kind = CK_Dynamic; 683} 684 685/// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid. 686/// Refer to C++ 5.2.11 for details. const_cast is typically used in code 687/// like this: 688/// const char *str = "literal"; 689/// legacy_function(const_cast\<char*\>(str)); 690void CastOperation::CheckConstCast() { 691 if (ValueKind == VK_RValue) 692 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 693 else if (isPlaceholder()) 694 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.take()); 695 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 696 return; 697 698 unsigned msg = diag::err_bad_cxx_cast_generic; 699 if (TryConstCast(Self, SrcExpr, DestType, /*CStyle*/false, msg) != TC_Success 700 && msg != 0) { 701 Self.Diag(OpRange.getBegin(), msg) << CT_Const 702 << SrcExpr.get()->getType() << DestType << OpRange; 703 SrcExpr = ExprError(); 704 } 705} 706 707/// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast 708/// or downcast between respective pointers or references. 709static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr, 710 QualType DestType, 711 SourceRange OpRange) { 712 QualType SrcType = SrcExpr->getType(); 713 // When casting from pointer or reference, get pointee type; use original 714 // type otherwise. 715 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl(); 716 const CXXRecordDecl *SrcRD = 717 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl(); 718 719 // Examining subobjects for records is only possible if the complete and 720 // valid definition is available. Also, template instantiation is not 721 // allowed here. 722 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl()) 723 return; 724 725 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl(); 726 727 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl()) 728 return; 729 730 enum { 731 ReinterpretUpcast, 732 ReinterpretDowncast 733 } ReinterpretKind; 734 735 CXXBasePaths BasePaths; 736 737 if (SrcRD->isDerivedFrom(DestRD, BasePaths)) 738 ReinterpretKind = ReinterpretUpcast; 739 else if (DestRD->isDerivedFrom(SrcRD, BasePaths)) 740 ReinterpretKind = ReinterpretDowncast; 741 else 742 return; 743 744 bool VirtualBase = true; 745 bool NonZeroOffset = false; 746 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(), 747 E = BasePaths.end(); 748 I != E; ++I) { 749 const CXXBasePath &Path = *I; 750 CharUnits Offset = CharUnits::Zero(); 751 bool IsVirtual = false; 752 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end(); 753 IElem != EElem; ++IElem) { 754 IsVirtual = IElem->Base->isVirtual(); 755 if (IsVirtual) 756 break; 757 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl(); 758 assert(BaseRD && "Base type should be a valid unqualified class type"); 759 // Don't check if any base has invalid declaration or has no definition 760 // since it has no layout info. 761 const CXXRecordDecl *Class = IElem->Class, 762 *ClassDefinition = Class->getDefinition(); 763 if (Class->isInvalidDecl() || !ClassDefinition || 764 !ClassDefinition->isCompleteDefinition()) 765 return; 766 767 const ASTRecordLayout &DerivedLayout = 768 Self.Context.getASTRecordLayout(Class); 769 Offset += DerivedLayout.getBaseClassOffset(BaseRD); 770 } 771 if (!IsVirtual) { 772 // Don't warn if any path is a non-virtually derived base at offset zero. 773 if (Offset.isZero()) 774 return; 775 // Offset makes sense only for non-virtual bases. 776 else 777 NonZeroOffset = true; 778 } 779 VirtualBase = VirtualBase && IsVirtual; 780 } 781 782 (void) NonZeroOffset; // Silence set but not used warning. 783 assert((VirtualBase || NonZeroOffset) && 784 "Should have returned if has non-virtual base with zero offset"); 785 786 QualType BaseType = 787 ReinterpretKind == ReinterpretUpcast? DestType : SrcType; 788 QualType DerivedType = 789 ReinterpretKind == ReinterpretUpcast? SrcType : DestType; 790 791 SourceLocation BeginLoc = OpRange.getBegin(); 792 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static) 793 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind) 794 << OpRange; 795 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static) 796 << int(ReinterpretKind) 797 << FixItHint::CreateReplacement(BeginLoc, "static_cast"); 798} 799 800/// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is 801/// valid. 802/// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code 803/// like this: 804/// char *bytes = reinterpret_cast\<char*\>(int_ptr); 805void CastOperation::CheckReinterpretCast() { 806 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload)) 807 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 808 else 809 checkNonOverloadPlaceholders(); 810 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 811 return; 812 813 unsigned msg = diag::err_bad_cxx_cast_generic; 814 TryCastResult tcr = 815 TryReinterpretCast(Self, SrcExpr, DestType, 816 /*CStyle*/false, OpRange, msg, Kind); 817 if (tcr != TC_Success && msg != 0) 818 { 819 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 820 return; 821 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 822 //FIXME: &f<int>; is overloaded and resolvable 823 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload) 824 << OverloadExpr::find(SrcExpr.get()).Expression->getName() 825 << DestType << OpRange; 826 Self.NoteAllOverloadCandidates(SrcExpr.get()); 827 828 } else { 829 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(), 830 DestType, /*listInitialization=*/false); 831 } 832 SrcExpr = ExprError(); 833 } else if (tcr == TC_Success) { 834 if (Self.getLangOpts().ObjCAutoRefCount) 835 checkObjCARCConversion(Sema::CCK_OtherCast); 836 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange); 837 } 838} 839 840 841/// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid. 842/// Refer to C++ 5.2.9 for details. Static casts are mostly used for making 843/// implicit conversions explicit and getting rid of data loss warnings. 844void CastOperation::CheckStaticCast() { 845 if (isPlaceholder()) { 846 checkNonOverloadPlaceholders(); 847 if (SrcExpr.isInvalid()) 848 return; 849 } 850 851 // This test is outside everything else because it's the only case where 852 // a non-lvalue-reference target type does not lead to decay. 853 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 854 if (DestType->isVoidType()) { 855 Kind = CK_ToVoid; 856 857 if (claimPlaceholder(BuiltinType::Overload)) { 858 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr, 859 false, // Decay Function to ptr 860 true, // Complain 861 OpRange, DestType, diag::err_bad_static_cast_overload); 862 if (SrcExpr.isInvalid()) 863 return; 864 } 865 866 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 867 return; 868 } 869 870 if (ValueKind == VK_RValue && !DestType->isRecordType() && 871 !isPlaceholder(BuiltinType::Overload)) { 872 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 873 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 874 return; 875 } 876 877 unsigned msg = diag::err_bad_cxx_cast_generic; 878 TryCastResult tcr 879 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg, 880 Kind, BasePath, /*ListInitialization=*/false); 881 if (tcr != TC_Success && msg != 0) { 882 if (SrcExpr.isInvalid()) 883 return; 884 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 885 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression; 886 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload) 887 << oe->getName() << DestType << OpRange 888 << oe->getQualifierLoc().getSourceRange(); 889 Self.NoteAllOverloadCandidates(SrcExpr.get()); 890 } else { 891 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType, 892 /*listInitialization=*/false); 893 } 894 SrcExpr = ExprError(); 895 } else if (tcr == TC_Success) { 896 if (Kind == CK_BitCast) 897 checkCastAlign(); 898 if (Self.getLangOpts().ObjCAutoRefCount) 899 checkObjCARCConversion(Sema::CCK_OtherCast); 900 } else if (Kind == CK_BitCast) { 901 checkCastAlign(); 902 } 903} 904 905/// TryStaticCast - Check if a static cast can be performed, and do so if 906/// possible. If @p CStyle, ignore access restrictions on hierarchy casting 907/// and casting away constness. 908static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, 909 QualType DestType, 910 Sema::CheckedConversionKind CCK, 911 const SourceRange &OpRange, unsigned &msg, 912 CastKind &Kind, CXXCastPath &BasePath, 913 bool ListInitialization) { 914 // Determine whether we have the semantics of a C-style cast. 915 bool CStyle 916 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 917 918 // The order the tests is not entirely arbitrary. There is one conversion 919 // that can be handled in two different ways. Given: 920 // struct A {}; 921 // struct B : public A { 922 // B(); B(const A&); 923 // }; 924 // const A &a = B(); 925 // the cast static_cast<const B&>(a) could be seen as either a static 926 // reference downcast, or an explicit invocation of the user-defined 927 // conversion using B's conversion constructor. 928 // DR 427 specifies that the downcast is to be applied here. 929 930 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 931 // Done outside this function. 932 933 TryCastResult tcr; 934 935 // C++ 5.2.9p5, reference downcast. 936 // See the function for details. 937 // DR 427 specifies that this is to be applied before paragraph 2. 938 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle, 939 OpRange, msg, Kind, BasePath); 940 if (tcr != TC_NotApplicable) 941 return tcr; 942 943 // C++0x [expr.static.cast]p3: 944 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2 945 // T2" if "cv2 T2" is reference-compatible with "cv1 T1". 946 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind, 947 BasePath, msg); 948 if (tcr != TC_NotApplicable) 949 return tcr; 950 951 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T 952 // [...] if the declaration "T t(e);" is well-formed, [...]. 953 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg, 954 Kind, ListInitialization); 955 if (SrcExpr.isInvalid()) 956 return TC_Failed; 957 if (tcr != TC_NotApplicable) 958 return tcr; 959 960 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except 961 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean 962 // conversions, subject to further restrictions. 963 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal 964 // of qualification conversions impossible. 965 // In the CStyle case, the earlier attempt to const_cast should have taken 966 // care of reverse qualification conversions. 967 968 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType()); 969 970 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly 971 // converted to an integral type. [...] A value of a scoped enumeration type 972 // can also be explicitly converted to a floating-point type [...]. 973 if (const EnumType *Enum = SrcType->getAs<EnumType>()) { 974 if (Enum->getDecl()->isScoped()) { 975 if (DestType->isBooleanType()) { 976 Kind = CK_IntegralToBoolean; 977 return TC_Success; 978 } else if (DestType->isIntegralType(Self.Context)) { 979 Kind = CK_IntegralCast; 980 return TC_Success; 981 } else if (DestType->isRealFloatingType()) { 982 Kind = CK_IntegralToFloating; 983 return TC_Success; 984 } 985 } 986 } 987 988 // Reverse integral promotion/conversion. All such conversions are themselves 989 // again integral promotions or conversions and are thus already handled by 990 // p2 (TryDirectInitialization above). 991 // (Note: any data loss warnings should be suppressed.) 992 // The exception is the reverse of enum->integer, i.e. integer->enum (and 993 // enum->enum). See also C++ 5.2.9p7. 994 // The same goes for reverse floating point promotion/conversion and 995 // floating-integral conversions. Again, only floating->enum is relevant. 996 if (DestType->isEnumeralType()) { 997 if (SrcType->isIntegralOrEnumerationType()) { 998 Kind = CK_IntegralCast; 999 return TC_Success; 1000 } else if (SrcType->isRealFloatingType()) { 1001 Kind = CK_FloatingToIntegral; 1002 return TC_Success; 1003 } 1004 } 1005 1006 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast. 1007 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance. 1008 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg, 1009 Kind, BasePath); 1010 if (tcr != TC_NotApplicable) 1011 return tcr; 1012 1013 // Reverse member pointer conversion. C++ 4.11 specifies member pointer 1014 // conversion. C++ 5.2.9p9 has additional information. 1015 // DR54's access restrictions apply here also. 1016 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle, 1017 OpRange, msg, Kind, BasePath); 1018 if (tcr != TC_NotApplicable) 1019 return tcr; 1020 1021 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to 1022 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is 1023 // just the usual constness stuff. 1024 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 1025 QualType SrcPointee = SrcPointer->getPointeeType(); 1026 if (SrcPointee->isVoidType()) { 1027 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) { 1028 QualType DestPointee = DestPointer->getPointeeType(); 1029 if (DestPointee->isIncompleteOrObjectType()) { 1030 // This is definitely the intended conversion, but it might fail due 1031 // to a qualifier violation. Note that we permit Objective-C lifetime 1032 // and GC qualifier mismatches here. 1033 if (!CStyle) { 1034 Qualifiers DestPointeeQuals = DestPointee.getQualifiers(); 1035 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers(); 1036 DestPointeeQuals.removeObjCGCAttr(); 1037 DestPointeeQuals.removeObjCLifetime(); 1038 SrcPointeeQuals.removeObjCGCAttr(); 1039 SrcPointeeQuals.removeObjCLifetime(); 1040 if (DestPointeeQuals != SrcPointeeQuals && 1041 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) { 1042 msg = diag::err_bad_cxx_cast_qualifiers_away; 1043 return TC_Failed; 1044 } 1045 } 1046 Kind = CK_BitCast; 1047 return TC_Success; 1048 } 1049 } 1050 else if (DestType->isObjCObjectPointerType()) { 1051 // allow both c-style cast and static_cast of objective-c pointers as 1052 // they are pervasive. 1053 Kind = CK_CPointerToObjCPointerCast; 1054 return TC_Success; 1055 } 1056 else if (CStyle && DestType->isBlockPointerType()) { 1057 // allow c-style cast of void * to block pointers. 1058 Kind = CK_AnyPointerToBlockPointerCast; 1059 return TC_Success; 1060 } 1061 } 1062 } 1063 // Allow arbitray objective-c pointer conversion with static casts. 1064 if (SrcType->isObjCObjectPointerType() && 1065 DestType->isObjCObjectPointerType()) { 1066 Kind = CK_BitCast; 1067 return TC_Success; 1068 } 1069 1070 // We tried everything. Everything! Nothing works! :-( 1071 return TC_NotApplicable; 1072} 1073 1074/// Tests whether a conversion according to N2844 is valid. 1075TryCastResult 1076TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, QualType DestType, 1077 bool CStyle, CastKind &Kind, CXXCastPath &BasePath, 1078 unsigned &msg) { 1079 // C++0x [expr.static.cast]p3: 1080 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to 1081 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1". 1082 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>(); 1083 if (!R) 1084 return TC_NotApplicable; 1085 1086 if (!SrcExpr->isGLValue()) 1087 return TC_NotApplicable; 1088 1089 // Because we try the reference downcast before this function, from now on 1090 // this is the only cast possibility, so we issue an error if we fail now. 1091 // FIXME: Should allow casting away constness if CStyle. 1092 bool DerivedToBase; 1093 bool ObjCConversion; 1094 bool ObjCLifetimeConversion; 1095 QualType FromType = SrcExpr->getType(); 1096 QualType ToType = R->getPointeeType(); 1097 if (CStyle) { 1098 FromType = FromType.getUnqualifiedType(); 1099 ToType = ToType.getUnqualifiedType(); 1100 } 1101 1102 if (Self.CompareReferenceRelationship(SrcExpr->getLocStart(), 1103 ToType, FromType, 1104 DerivedToBase, ObjCConversion, 1105 ObjCLifetimeConversion) 1106 < Sema::Ref_Compatible_With_Added_Qualification) { 1107 msg = diag::err_bad_lvalue_to_rvalue_cast; 1108 return TC_Failed; 1109 } 1110 1111 if (DerivedToBase) { 1112 Kind = CK_DerivedToBase; 1113 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1114 /*DetectVirtual=*/true); 1115 if (!Self.IsDerivedFrom(SrcExpr->getType(), R->getPointeeType(), Paths)) 1116 return TC_NotApplicable; 1117 1118 Self.BuildBasePathArray(Paths, BasePath); 1119 } else 1120 Kind = CK_NoOp; 1121 1122 return TC_Success; 1123} 1124 1125/// Tests whether a conversion according to C++ 5.2.9p5 is valid. 1126TryCastResult 1127TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType, 1128 bool CStyle, const SourceRange &OpRange, 1129 unsigned &msg, CastKind &Kind, 1130 CXXCastPath &BasePath) { 1131 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be 1132 // cast to type "reference to cv2 D", where D is a class derived from B, 1133 // if a valid standard conversion from "pointer to D" to "pointer to B" 1134 // exists, cv2 >= cv1, and B is not a virtual base class of D. 1135 // In addition, DR54 clarifies that the base must be accessible in the 1136 // current context. Although the wording of DR54 only applies to the pointer 1137 // variant of this rule, the intent is clearly for it to apply to the this 1138 // conversion as well. 1139 1140 const ReferenceType *DestReference = DestType->getAs<ReferenceType>(); 1141 if (!DestReference) { 1142 return TC_NotApplicable; 1143 } 1144 bool RValueRef = DestReference->isRValueReferenceType(); 1145 if (!RValueRef && !SrcExpr->isLValue()) { 1146 // We know the left side is an lvalue reference, so we can suggest a reason. 1147 msg = diag::err_bad_cxx_cast_rvalue; 1148 return TC_NotApplicable; 1149 } 1150 1151 QualType DestPointee = DestReference->getPointeeType(); 1152 1153 return TryStaticDowncast(Self, 1154 Self.Context.getCanonicalType(SrcExpr->getType()), 1155 Self.Context.getCanonicalType(DestPointee), CStyle, 1156 OpRange, SrcExpr->getType(), DestType, msg, Kind, 1157 BasePath); 1158} 1159 1160/// Tests whether a conversion according to C++ 5.2.9p8 is valid. 1161TryCastResult 1162TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType, 1163 bool CStyle, const SourceRange &OpRange, 1164 unsigned &msg, CastKind &Kind, 1165 CXXCastPath &BasePath) { 1166 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class 1167 // type, can be converted to an rvalue of type "pointer to cv2 D", where D 1168 // is a class derived from B, if a valid standard conversion from "pointer 1169 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base 1170 // class of D. 1171 // In addition, DR54 clarifies that the base must be accessible in the 1172 // current context. 1173 1174 const PointerType *DestPointer = DestType->getAs<PointerType>(); 1175 if (!DestPointer) { 1176 return TC_NotApplicable; 1177 } 1178 1179 const PointerType *SrcPointer = SrcType->getAs<PointerType>(); 1180 if (!SrcPointer) { 1181 msg = diag::err_bad_static_cast_pointer_nonpointer; 1182 return TC_NotApplicable; 1183 } 1184 1185 return TryStaticDowncast(Self, 1186 Self.Context.getCanonicalType(SrcPointer->getPointeeType()), 1187 Self.Context.getCanonicalType(DestPointer->getPointeeType()), 1188 CStyle, OpRange, SrcType, DestType, msg, Kind, 1189 BasePath); 1190} 1191 1192/// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and 1193/// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to 1194/// DestType is possible and allowed. 1195TryCastResult 1196TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType, 1197 bool CStyle, const SourceRange &OpRange, QualType OrigSrcType, 1198 QualType OrigDestType, unsigned &msg, 1199 CastKind &Kind, CXXCastPath &BasePath) { 1200 // We can only work with complete types. But don't complain if it doesn't work 1201 if (Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0) || 1202 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0)) 1203 return TC_NotApplicable; 1204 1205 // Downcast can only happen in class hierarchies, so we need classes. 1206 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) { 1207 return TC_NotApplicable; 1208 } 1209 1210 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1211 /*DetectVirtual=*/true); 1212 if (!Self.IsDerivedFrom(DestType, SrcType, Paths)) { 1213 return TC_NotApplicable; 1214 } 1215 1216 // Target type does derive from source type. Now we're serious. If an error 1217 // appears now, it's not ignored. 1218 // This may not be entirely in line with the standard. Take for example: 1219 // struct A {}; 1220 // struct B : virtual A { 1221 // B(A&); 1222 // }; 1223 // 1224 // void f() 1225 // { 1226 // (void)static_cast<const B&>(*((A*)0)); 1227 // } 1228 // As far as the standard is concerned, p5 does not apply (A is virtual), so 1229 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid. 1230 // However, both GCC and Comeau reject this example, and accepting it would 1231 // mean more complex code if we're to preserve the nice error message. 1232 // FIXME: Being 100% compliant here would be nice to have. 1233 1234 // Must preserve cv, as always, unless we're in C-style mode. 1235 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) { 1236 msg = diag::err_bad_cxx_cast_qualifiers_away; 1237 return TC_Failed; 1238 } 1239 1240 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) { 1241 // This code is analoguous to that in CheckDerivedToBaseConversion, except 1242 // that it builds the paths in reverse order. 1243 // To sum up: record all paths to the base and build a nice string from 1244 // them. Use it to spice up the error message. 1245 if (!Paths.isRecordingPaths()) { 1246 Paths.clear(); 1247 Paths.setRecordingPaths(true); 1248 Self.IsDerivedFrom(DestType, SrcType, Paths); 1249 } 1250 std::string PathDisplayStr; 1251 std::set<unsigned> DisplayedPaths; 1252 for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end(); 1253 PI != PE; ++PI) { 1254 if (DisplayedPaths.insert(PI->back().SubobjectNumber).second) { 1255 // We haven't displayed a path to this particular base 1256 // class subobject yet. 1257 PathDisplayStr += "\n "; 1258 for (CXXBasePath::const_reverse_iterator EI = PI->rbegin(), 1259 EE = PI->rend(); 1260 EI != EE; ++EI) 1261 PathDisplayStr += EI->Base->getType().getAsString() + " -> "; 1262 PathDisplayStr += QualType(DestType).getAsString(); 1263 } 1264 } 1265 1266 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast) 1267 << QualType(SrcType).getUnqualifiedType() 1268 << QualType(DestType).getUnqualifiedType() 1269 << PathDisplayStr << OpRange; 1270 msg = 0; 1271 return TC_Failed; 1272 } 1273 1274 if (Paths.getDetectedVirtual() != 0) { 1275 QualType VirtualBase(Paths.getDetectedVirtual(), 0); 1276 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual) 1277 << OrigSrcType << OrigDestType << VirtualBase << OpRange; 1278 msg = 0; 1279 return TC_Failed; 1280 } 1281 1282 if (!CStyle) { 1283 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1284 SrcType, DestType, 1285 Paths.front(), 1286 diag::err_downcast_from_inaccessible_base)) { 1287 case Sema::AR_accessible: 1288 case Sema::AR_delayed: // be optimistic 1289 case Sema::AR_dependent: // be optimistic 1290 break; 1291 1292 case Sema::AR_inaccessible: 1293 msg = 0; 1294 return TC_Failed; 1295 } 1296 } 1297 1298 Self.BuildBasePathArray(Paths, BasePath); 1299 Kind = CK_BaseToDerived; 1300 return TC_Success; 1301} 1302 1303/// TryStaticMemberPointerUpcast - Tests whether a conversion according to 1304/// C++ 5.2.9p9 is valid: 1305/// 1306/// An rvalue of type "pointer to member of D of type cv1 T" can be 1307/// converted to an rvalue of type "pointer to member of B of type cv2 T", 1308/// where B is a base class of D [...]. 1309/// 1310TryCastResult 1311TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType, 1312 QualType DestType, bool CStyle, 1313 const SourceRange &OpRange, 1314 unsigned &msg, CastKind &Kind, 1315 CXXCastPath &BasePath) { 1316 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(); 1317 if (!DestMemPtr) 1318 return TC_NotApplicable; 1319 1320 bool WasOverloadedFunction = false; 1321 DeclAccessPair FoundOverload; 1322 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 1323 if (FunctionDecl *Fn 1324 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false, 1325 FoundOverload)) { 1326 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 1327 SrcType = Self.Context.getMemberPointerType(Fn->getType(), 1328 Self.Context.getTypeDeclType(M->getParent()).getTypePtr()); 1329 WasOverloadedFunction = true; 1330 } 1331 } 1332 1333 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1334 if (!SrcMemPtr) { 1335 msg = diag::err_bad_static_cast_member_pointer_nonmp; 1336 return TC_NotApplicable; 1337 } 1338 1339 // T == T, modulo cv 1340 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(), 1341 DestMemPtr->getPointeeType())) 1342 return TC_NotApplicable; 1343 1344 // B base of D 1345 QualType SrcClass(SrcMemPtr->getClass(), 0); 1346 QualType DestClass(DestMemPtr->getClass(), 0); 1347 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1348 /*DetectVirtual=*/true); 1349 if (!Self.IsDerivedFrom(SrcClass, DestClass, Paths)) { 1350 return TC_NotApplicable; 1351 } 1352 1353 // B is a base of D. But is it an allowed base? If not, it's a hard error. 1354 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) { 1355 Paths.clear(); 1356 Paths.setRecordingPaths(true); 1357 bool StillOkay = Self.IsDerivedFrom(SrcClass, DestClass, Paths); 1358 assert(StillOkay); 1359 (void)StillOkay; 1360 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths); 1361 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv) 1362 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange; 1363 msg = 0; 1364 return TC_Failed; 1365 } 1366 1367 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1368 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual) 1369 << SrcClass << DestClass << QualType(VBase, 0) << OpRange; 1370 msg = 0; 1371 return TC_Failed; 1372 } 1373 1374 if (!CStyle) { 1375 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1376 DestClass, SrcClass, 1377 Paths.front(), 1378 diag::err_upcast_to_inaccessible_base)) { 1379 case Sema::AR_accessible: 1380 case Sema::AR_delayed: 1381 case Sema::AR_dependent: 1382 // Optimistically assume that the delayed and dependent cases 1383 // will work out. 1384 break; 1385 1386 case Sema::AR_inaccessible: 1387 msg = 0; 1388 return TC_Failed; 1389 } 1390 } 1391 1392 if (WasOverloadedFunction) { 1393 // Resolve the address of the overloaded function again, this time 1394 // allowing complaints if something goes wrong. 1395 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 1396 DestType, 1397 true, 1398 FoundOverload); 1399 if (!Fn) { 1400 msg = 0; 1401 return TC_Failed; 1402 } 1403 1404 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn); 1405 if (!SrcExpr.isUsable()) { 1406 msg = 0; 1407 return TC_Failed; 1408 } 1409 } 1410 1411 Self.BuildBasePathArray(Paths, BasePath); 1412 Kind = CK_DerivedToBaseMemberPointer; 1413 return TC_Success; 1414} 1415 1416/// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2 1417/// is valid: 1418/// 1419/// An expression e can be explicitly converted to a type T using a 1420/// @c static_cast if the declaration "T t(e);" is well-formed [...]. 1421TryCastResult 1422TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType, 1423 Sema::CheckedConversionKind CCK, 1424 const SourceRange &OpRange, unsigned &msg, 1425 CastKind &Kind, bool ListInitialization) { 1426 if (DestType->isRecordType()) { 1427 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 1428 diag::err_bad_dynamic_cast_incomplete) || 1429 Self.RequireNonAbstractType(OpRange.getBegin(), DestType, 1430 diag::err_allocation_of_abstract_type)) { 1431 msg = 0; 1432 return TC_Failed; 1433 } 1434 } 1435 1436 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType); 1437 InitializationKind InitKind 1438 = (CCK == Sema::CCK_CStyleCast) 1439 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange, 1440 ListInitialization) 1441 : (CCK == Sema::CCK_FunctionalCast) 1442 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization) 1443 : InitializationKind::CreateCast(OpRange); 1444 Expr *SrcExprRaw = SrcExpr.get(); 1445 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw); 1446 1447 // At this point of CheckStaticCast, if the destination is a reference, 1448 // or the expression is an overload expression this has to work. 1449 // There is no other way that works. 1450 // On the other hand, if we're checking a C-style cast, we've still got 1451 // the reinterpret_cast way. 1452 bool CStyle 1453 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 1454 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType())) 1455 return TC_NotApplicable; 1456 1457 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw); 1458 if (Result.isInvalid()) { 1459 msg = 0; 1460 return TC_Failed; 1461 } 1462 1463 if (InitSeq.isConstructorInitialization()) 1464 Kind = CK_ConstructorConversion; 1465 else 1466 Kind = CK_NoOp; 1467 1468 SrcExpr = Result; 1469 return TC_Success; 1470} 1471 1472/// TryConstCast - See if a const_cast from source to destination is allowed, 1473/// and perform it if it is. 1474static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, 1475 QualType DestType, bool CStyle, 1476 unsigned &msg) { 1477 DestType = Self.Context.getCanonicalType(DestType); 1478 QualType SrcType = SrcExpr.get()->getType(); 1479 bool NeedToMaterializeTemporary = false; 1480 1481 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) { 1482 // C++11 5.2.11p4: 1483 // if a pointer to T1 can be explicitly converted to the type "pointer to 1484 // T2" using a const_cast, then the following conversions can also be 1485 // made: 1486 // -- an lvalue of type T1 can be explicitly converted to an lvalue of 1487 // type T2 using the cast const_cast<T2&>; 1488 // -- a glvalue of type T1 can be explicitly converted to an xvalue of 1489 // type T2 using the cast const_cast<T2&&>; and 1490 // -- if T1 is a class type, a prvalue of type T1 can be explicitly 1491 // converted to an xvalue of type T2 using the cast const_cast<T2&&>. 1492 1493 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) { 1494 // Cannot const_cast non-lvalue to lvalue reference type. But if this 1495 // is C-style, static_cast might find a way, so we simply suggest a 1496 // message and tell the parent to keep searching. 1497 msg = diag::err_bad_cxx_cast_rvalue; 1498 return TC_NotApplicable; 1499 } 1500 1501 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) { 1502 if (!SrcType->isRecordType()) { 1503 // Cannot const_cast non-class prvalue to rvalue reference type. But if 1504 // this is C-style, static_cast can do this. 1505 msg = diag::err_bad_cxx_cast_rvalue; 1506 return TC_NotApplicable; 1507 } 1508 1509 // Materialize the class prvalue so that the const_cast can bind a 1510 // reference to it. 1511 NeedToMaterializeTemporary = true; 1512 } 1513 1514 // It's not completely clear under the standard whether we can 1515 // const_cast bit-field gl-values. Doing so would not be 1516 // intrinsically complicated, but for now, we say no for 1517 // consistency with other compilers and await the word of the 1518 // committee. 1519 if (SrcExpr.get()->refersToBitField()) { 1520 msg = diag::err_bad_cxx_cast_bitfield; 1521 return TC_NotApplicable; 1522 } 1523 1524 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1525 SrcType = Self.Context.getPointerType(SrcType); 1526 } 1527 1528 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...] 1529 // the rules for const_cast are the same as those used for pointers. 1530 1531 if (!DestType->isPointerType() && 1532 !DestType->isMemberPointerType() && 1533 !DestType->isObjCObjectPointerType()) { 1534 // Cannot cast to non-pointer, non-reference type. Note that, if DestType 1535 // was a reference type, we converted it to a pointer above. 1536 // The status of rvalue references isn't entirely clear, but it looks like 1537 // conversion to them is simply invalid. 1538 // C++ 5.2.11p3: For two pointer types [...] 1539 if (!CStyle) 1540 msg = diag::err_bad_const_cast_dest; 1541 return TC_NotApplicable; 1542 } 1543 if (DestType->isFunctionPointerType() || 1544 DestType->isMemberFunctionPointerType()) { 1545 // Cannot cast direct function pointers. 1546 // C++ 5.2.11p2: [...] where T is any object type or the void type [...] 1547 // T is the ultimate pointee of source and target type. 1548 if (!CStyle) 1549 msg = diag::err_bad_const_cast_dest; 1550 return TC_NotApplicable; 1551 } 1552 SrcType = Self.Context.getCanonicalType(SrcType); 1553 1554 // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are 1555 // completely equal. 1556 // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers 1557 // in multi-level pointers may change, but the level count must be the same, 1558 // as must be the final pointee type. 1559 while (SrcType != DestType && 1560 Self.Context.UnwrapSimilarPointerTypes(SrcType, DestType)) { 1561 Qualifiers SrcQuals, DestQuals; 1562 SrcType = Self.Context.getUnqualifiedArrayType(SrcType, SrcQuals); 1563 DestType = Self.Context.getUnqualifiedArrayType(DestType, DestQuals); 1564 1565 // const_cast is permitted to strip cvr-qualifiers, only. Make sure that 1566 // the other qualifiers (e.g., address spaces) are identical. 1567 SrcQuals.removeCVRQualifiers(); 1568 DestQuals.removeCVRQualifiers(); 1569 if (SrcQuals != DestQuals) 1570 return TC_NotApplicable; 1571 } 1572 1573 // Since we're dealing in canonical types, the remainder must be the same. 1574 if (SrcType != DestType) 1575 return TC_NotApplicable; 1576 1577 if (NeedToMaterializeTemporary) 1578 // This is a const_cast from a class prvalue to an rvalue reference type. 1579 // Materialize a temporary to store the result of the conversion. 1580 SrcExpr = new (Self.Context) MaterializeTemporaryExpr( 1581 SrcType, SrcExpr.take(), /*IsLValueReference*/ false, 1582 /*ExtendingDecl*/ 0); 1583 1584 return TC_Success; 1585} 1586 1587// Checks for undefined behavior in reinterpret_cast. 1588// The cases that is checked for is: 1589// *reinterpret_cast<T*>(&a) 1590// reinterpret_cast<T&>(a) 1591// where accessing 'a' as type 'T' will result in undefined behavior. 1592void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType, 1593 bool IsDereference, 1594 SourceRange Range) { 1595 unsigned DiagID = IsDereference ? 1596 diag::warn_pointer_indirection_from_incompatible_type : 1597 diag::warn_undefined_reinterpret_cast; 1598 1599 if (Diags.getDiagnosticLevel(DiagID, Range.getBegin()) == 1600 DiagnosticsEngine::Ignored) { 1601 return; 1602 } 1603 1604 QualType SrcTy, DestTy; 1605 if (IsDereference) { 1606 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) { 1607 return; 1608 } 1609 SrcTy = SrcType->getPointeeType(); 1610 DestTy = DestType->getPointeeType(); 1611 } else { 1612 if (!DestType->getAs<ReferenceType>()) { 1613 return; 1614 } 1615 SrcTy = SrcType; 1616 DestTy = DestType->getPointeeType(); 1617 } 1618 1619 // Cast is compatible if the types are the same. 1620 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) { 1621 return; 1622 } 1623 // or one of the types is a char or void type 1624 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() || 1625 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) { 1626 return; 1627 } 1628 // or one of the types is a tag type. 1629 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) { 1630 return; 1631 } 1632 1633 // FIXME: Scoped enums? 1634 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) || 1635 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) { 1636 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) { 1637 return; 1638 } 1639 } 1640 1641 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range; 1642} 1643 1644static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr, 1645 QualType DestType) { 1646 QualType SrcType = SrcExpr.get()->getType(); 1647 if (Self.Context.hasSameType(SrcType, DestType)) 1648 return; 1649 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>()) 1650 if (SrcPtrTy->isObjCSelType()) { 1651 QualType DT = DestType; 1652 if (isa<PointerType>(DestType)) 1653 DT = DestType->getPointeeType(); 1654 if (!DT.getUnqualifiedType()->isVoidType()) 1655 Self.Diag(SrcExpr.get()->getExprLoc(), 1656 diag::warn_cast_pointer_from_sel) 1657 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 1658 } 1659} 1660 1661static void checkIntToPointerCast(bool CStyle, SourceLocation Loc, 1662 const Expr *SrcExpr, QualType DestType, 1663 Sema &Self) { 1664 QualType SrcType = SrcExpr->getType(); 1665 1666 // Not warning on reinterpret_cast, boolean, constant expressions, etc 1667 // are not explicit design choices, but consistent with GCC's behavior. 1668 // Feel free to modify them if you've reason/evidence for an alternative. 1669 if (CStyle && SrcType->isIntegralType(Self.Context) 1670 && !SrcType->isBooleanType() 1671 && !SrcType->isEnumeralType() 1672 && !SrcExpr->isIntegerConstantExpr(Self.Context) 1673 && Self.Context.getTypeSize(DestType) > 1674 Self.Context.getTypeSize(SrcType)) { 1675 // Separate between casts to void* and non-void* pointers. 1676 // Some APIs use (abuse) void* for something like a user context, 1677 // and often that value is an integer even if it isn't a pointer itself. 1678 // Having a separate warning flag allows users to control the warning 1679 // for their workflow. 1680 unsigned Diag = DestType->isVoidPointerType() ? 1681 diag::warn_int_to_void_pointer_cast 1682 : diag::warn_int_to_pointer_cast; 1683 Self.Diag(Loc, Diag) << SrcType << DestType; 1684 } 1685} 1686 1687static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 1688 QualType DestType, bool CStyle, 1689 const SourceRange &OpRange, 1690 unsigned &msg, 1691 CastKind &Kind) { 1692 bool IsLValueCast = false; 1693 1694 DestType = Self.Context.getCanonicalType(DestType); 1695 QualType SrcType = SrcExpr.get()->getType(); 1696 1697 // Is the source an overloaded name? (i.e. &foo) 1698 // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5) ... 1699 if (SrcType == Self.Context.OverloadTy) { 1700 // ... unless foo<int> resolves to an lvalue unambiguously. 1701 // TODO: what if this fails because of DiagnoseUseOfDecl or something 1702 // like it? 1703 ExprResult SingleFunctionExpr = SrcExpr; 1704 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization( 1705 SingleFunctionExpr, 1706 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr 1707 ) && SingleFunctionExpr.isUsable()) { 1708 SrcExpr = SingleFunctionExpr; 1709 SrcType = SrcExpr.get()->getType(); 1710 } else { 1711 return TC_NotApplicable; 1712 } 1713 } 1714 1715 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) { 1716 if (!SrcExpr.get()->isGLValue()) { 1717 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the 1718 // similar comment in const_cast. 1719 msg = diag::err_bad_cxx_cast_rvalue; 1720 return TC_NotApplicable; 1721 } 1722 1723 if (!CStyle) { 1724 Self.CheckCompatibleReinterpretCast(SrcType, DestType, 1725 /*isDereference=*/false, OpRange); 1726 } 1727 1728 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the 1729 // same effect as the conversion *reinterpret_cast<T*>(&x) with the 1730 // built-in & and * operators. 1731 1732 const char *inappropriate = 0; 1733 switch (SrcExpr.get()->getObjectKind()) { 1734 case OK_Ordinary: 1735 break; 1736 case OK_BitField: inappropriate = "bit-field"; break; 1737 case OK_VectorComponent: inappropriate = "vector element"; break; 1738 case OK_ObjCProperty: inappropriate = "property expression"; break; 1739 case OK_ObjCSubscript: inappropriate = "container subscripting expression"; 1740 break; 1741 } 1742 if (inappropriate) { 1743 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference) 1744 << inappropriate << DestType 1745 << OpRange << SrcExpr.get()->getSourceRange(); 1746 msg = 0; SrcExpr = ExprError(); 1747 return TC_NotApplicable; 1748 } 1749 1750 // This code does this transformation for the checked types. 1751 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1752 SrcType = Self.Context.getPointerType(SrcType); 1753 1754 IsLValueCast = true; 1755 } 1756 1757 // Canonicalize source for comparison. 1758 SrcType = Self.Context.getCanonicalType(SrcType); 1759 1760 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(), 1761 *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1762 if (DestMemPtr && SrcMemPtr) { 1763 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1" 1764 // can be explicitly converted to an rvalue of type "pointer to member 1765 // of Y of type T2" if T1 and T2 are both function types or both object 1766 // types. 1767 if (DestMemPtr->getPointeeType()->isFunctionType() != 1768 SrcMemPtr->getPointeeType()->isFunctionType()) 1769 return TC_NotApplicable; 1770 1771 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away 1772 // constness. 1773 // A reinterpret_cast followed by a const_cast can, though, so in C-style, 1774 // we accept it. 1775 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1776 /*CheckObjCLifetime=*/CStyle)) { 1777 msg = diag::err_bad_cxx_cast_qualifiers_away; 1778 return TC_Failed; 1779 } 1780 1781 // Don't allow casting between member pointers of different sizes. 1782 if (Self.Context.getTypeSize(DestMemPtr) != 1783 Self.Context.getTypeSize(SrcMemPtr)) { 1784 msg = diag::err_bad_cxx_cast_member_pointer_size; 1785 return TC_Failed; 1786 } 1787 1788 // A valid member pointer cast. 1789 assert(!IsLValueCast); 1790 Kind = CK_ReinterpretMemberPointer; 1791 return TC_Success; 1792 } 1793 1794 // See below for the enumeral issue. 1795 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) { 1796 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral 1797 // type large enough to hold it. A value of std::nullptr_t can be 1798 // converted to an integral type; the conversion has the same meaning 1799 // and validity as a conversion of (void*)0 to the integral type. 1800 if (Self.Context.getTypeSize(SrcType) > 1801 Self.Context.getTypeSize(DestType)) { 1802 msg = diag::err_bad_reinterpret_cast_small_int; 1803 return TC_Failed; 1804 } 1805 Kind = CK_PointerToIntegral; 1806 return TC_Success; 1807 } 1808 1809 bool destIsVector = DestType->isVectorType(); 1810 bool srcIsVector = SrcType->isVectorType(); 1811 if (srcIsVector || destIsVector) { 1812 // FIXME: Should this also apply to floating point types? 1813 bool srcIsScalar = SrcType->isIntegralType(Self.Context); 1814 bool destIsScalar = DestType->isIntegralType(Self.Context); 1815 1816 // Check if this is a cast between a vector and something else. 1817 if (!(srcIsScalar && destIsVector) && !(srcIsVector && destIsScalar) && 1818 !(srcIsVector && destIsVector)) 1819 return TC_NotApplicable; 1820 1821 // If both types have the same size, we can successfully cast. 1822 if (Self.Context.getTypeSize(SrcType) 1823 == Self.Context.getTypeSize(DestType)) { 1824 Kind = CK_BitCast; 1825 return TC_Success; 1826 } 1827 1828 if (destIsScalar) 1829 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size; 1830 else if (srcIsScalar) 1831 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size; 1832 else 1833 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size; 1834 1835 return TC_Failed; 1836 } 1837 1838 if (SrcType == DestType) { 1839 // C++ 5.2.10p2 has a note that mentions that, subject to all other 1840 // restrictions, a cast to the same type is allowed so long as it does not 1841 // cast away constness. In C++98, the intent was not entirely clear here, 1842 // since all other paragraphs explicitly forbid casts to the same type. 1843 // C++11 clarifies this case with p2. 1844 // 1845 // The only allowed types are: integral, enumeration, pointer, or 1846 // pointer-to-member types. We also won't restrict Obj-C pointers either. 1847 Kind = CK_NoOp; 1848 TryCastResult Result = TC_NotApplicable; 1849 if (SrcType->isIntegralOrEnumerationType() || 1850 SrcType->isAnyPointerType() || 1851 SrcType->isMemberPointerType() || 1852 SrcType->isBlockPointerType()) { 1853 Result = TC_Success; 1854 } 1855 return Result; 1856 } 1857 1858 bool destIsPtr = DestType->isAnyPointerType() || 1859 DestType->isBlockPointerType(); 1860 bool srcIsPtr = SrcType->isAnyPointerType() || 1861 SrcType->isBlockPointerType(); 1862 if (!destIsPtr && !srcIsPtr) { 1863 // Except for std::nullptr_t->integer and lvalue->reference, which are 1864 // handled above, at least one of the two arguments must be a pointer. 1865 return TC_NotApplicable; 1866 } 1867 1868 if (DestType->isIntegralType(Self.Context)) { 1869 assert(srcIsPtr && "One type must be a pointer"); 1870 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral 1871 // type large enough to hold it; except in Microsoft mode, where the 1872 // integral type size doesn't matter (except we don't allow bool). 1873 bool MicrosoftException = Self.getLangOpts().MicrosoftExt && 1874 !DestType->isBooleanType(); 1875 if ((Self.Context.getTypeSize(SrcType) > 1876 Self.Context.getTypeSize(DestType)) && 1877 !MicrosoftException) { 1878 msg = diag::err_bad_reinterpret_cast_small_int; 1879 return TC_Failed; 1880 } 1881 Kind = CK_PointerToIntegral; 1882 return TC_Success; 1883 } 1884 1885 if (SrcType->isIntegralOrEnumerationType()) { 1886 assert(destIsPtr && "One type must be a pointer"); 1887 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType, 1888 Self); 1889 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly 1890 // converted to a pointer. 1891 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not 1892 // necessarily converted to a null pointer value.] 1893 Kind = CK_IntegralToPointer; 1894 return TC_Success; 1895 } 1896 1897 if (!destIsPtr || !srcIsPtr) { 1898 // With the valid non-pointer conversions out of the way, we can be even 1899 // more stringent. 1900 return TC_NotApplicable; 1901 } 1902 1903 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness. 1904 // The C-style cast operator can. 1905 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1906 /*CheckObjCLifetime=*/CStyle)) { 1907 msg = diag::err_bad_cxx_cast_qualifiers_away; 1908 return TC_Failed; 1909 } 1910 1911 // Cannot convert between block pointers and Objective-C object pointers. 1912 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) || 1913 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType())) 1914 return TC_NotApplicable; 1915 1916 if (IsLValueCast) { 1917 Kind = CK_LValueBitCast; 1918 } else if (DestType->isObjCObjectPointerType()) { 1919 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr); 1920 } else if (DestType->isBlockPointerType()) { 1921 if (!SrcType->isBlockPointerType()) { 1922 Kind = CK_AnyPointerToBlockPointerCast; 1923 } else { 1924 Kind = CK_BitCast; 1925 } 1926 } else { 1927 Kind = CK_BitCast; 1928 } 1929 1930 // Any pointer can be cast to an Objective-C pointer type with a C-style 1931 // cast. 1932 if (CStyle && DestType->isObjCObjectPointerType()) { 1933 return TC_Success; 1934 } 1935 if (CStyle) 1936 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 1937 1938 // Not casting away constness, so the only remaining check is for compatible 1939 // pointer categories. 1940 1941 if (SrcType->isFunctionPointerType()) { 1942 if (DestType->isFunctionPointerType()) { 1943 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to 1944 // a pointer to a function of a different type. 1945 return TC_Success; 1946 } 1947 1948 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to 1949 // an object type or vice versa is conditionally-supported. 1950 // Compilers support it in C++03 too, though, because it's necessary for 1951 // casting the return value of dlsym() and GetProcAddress(). 1952 // FIXME: Conditionally-supported behavior should be configurable in the 1953 // TargetInfo or similar. 1954 Self.Diag(OpRange.getBegin(), 1955 Self.getLangOpts().CPlusPlus11 ? 1956 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1957 << OpRange; 1958 return TC_Success; 1959 } 1960 1961 if (DestType->isFunctionPointerType()) { 1962 // See above. 1963 Self.Diag(OpRange.getBegin(), 1964 Self.getLangOpts().CPlusPlus11 ? 1965 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1966 << OpRange; 1967 return TC_Success; 1968 } 1969 1970 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to 1971 // a pointer to an object of different type. 1972 // Void pointers are not specified, but supported by every compiler out there. 1973 // So we finish by allowing everything that remains - it's got to be two 1974 // object pointers. 1975 return TC_Success; 1976} 1977 1978void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle, 1979 bool ListInitialization) { 1980 // Handle placeholders. 1981 if (isPlaceholder()) { 1982 // C-style casts can resolve __unknown_any types. 1983 if (claimPlaceholder(BuiltinType::UnknownAny)) { 1984 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 1985 SrcExpr.get(), Kind, 1986 ValueKind, BasePath); 1987 return; 1988 } 1989 1990 checkNonOverloadPlaceholders(); 1991 if (SrcExpr.isInvalid()) 1992 return; 1993 } 1994 1995 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 1996 // This test is outside everything else because it's the only case where 1997 // a non-lvalue-reference target type does not lead to decay. 1998 if (DestType->isVoidType()) { 1999 Kind = CK_ToVoid; 2000 2001 if (claimPlaceholder(BuiltinType::Overload)) { 2002 Self.ResolveAndFixSingleFunctionTemplateSpecialization( 2003 SrcExpr, /* Decay Function to ptr */ false, 2004 /* Complain */ true, DestRange, DestType, 2005 diag::err_bad_cstyle_cast_overload); 2006 if (SrcExpr.isInvalid()) 2007 return; 2008 } 2009 2010 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 2011 return; 2012 } 2013 2014 // If the type is dependent, we won't do any other semantic analysis now. 2015 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() || 2016 SrcExpr.get()->isValueDependent()) { 2017 assert(Kind == CK_Dependent); 2018 return; 2019 } 2020 2021 if (ValueKind == VK_RValue && !DestType->isRecordType() && 2022 !isPlaceholder(BuiltinType::Overload)) { 2023 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 2024 if (SrcExpr.isInvalid()) 2025 return; 2026 } 2027 2028 // AltiVec vector initialization with a single literal. 2029 if (const VectorType *vecTy = DestType->getAs<VectorType>()) 2030 if (vecTy->getVectorKind() == VectorType::AltiVecVector 2031 && (SrcExpr.get()->getType()->isIntegerType() 2032 || SrcExpr.get()->getType()->isFloatingType())) { 2033 Kind = CK_VectorSplat; 2034 return; 2035 } 2036 2037 // C++ [expr.cast]p5: The conversions performed by 2038 // - a const_cast, 2039 // - a static_cast, 2040 // - a static_cast followed by a const_cast, 2041 // - a reinterpret_cast, or 2042 // - a reinterpret_cast followed by a const_cast, 2043 // can be performed using the cast notation of explicit type conversion. 2044 // [...] If a conversion can be interpreted in more than one of the ways 2045 // listed above, the interpretation that appears first in the list is used, 2046 // even if a cast resulting from that interpretation is ill-formed. 2047 // In plain language, this means trying a const_cast ... 2048 unsigned msg = diag::err_bad_cxx_cast_generic; 2049 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType, 2050 /*CStyle*/true, msg); 2051 if (SrcExpr.isInvalid()) 2052 return; 2053 if (tcr == TC_Success) 2054 Kind = CK_NoOp; 2055 2056 Sema::CheckedConversionKind CCK 2057 = FunctionalStyle? Sema::CCK_FunctionalCast 2058 : Sema::CCK_CStyleCast; 2059 if (tcr == TC_NotApplicable) { 2060 // ... or if that is not possible, a static_cast, ignoring const, ... 2061 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, 2062 msg, Kind, BasePath, ListInitialization); 2063 if (SrcExpr.isInvalid()) 2064 return; 2065 2066 if (tcr == TC_NotApplicable) { 2067 // ... and finally a reinterpret_cast, ignoring const. 2068 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true, 2069 OpRange, msg, Kind); 2070 if (SrcExpr.isInvalid()) 2071 return; 2072 } 2073 } 2074 2075 if (Self.getLangOpts().ObjCAutoRefCount && tcr == TC_Success) 2076 checkObjCARCConversion(CCK); 2077 2078 if (tcr != TC_Success && msg != 0) { 2079 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 2080 DeclAccessPair Found; 2081 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 2082 DestType, 2083 /*Complain*/ true, 2084 Found); 2085 2086 assert(!Fn && "cast failed but able to resolve overload expression!!"); 2087 (void)Fn; 2088 2089 } else { 2090 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle), 2091 OpRange, SrcExpr.get(), DestType, ListInitialization); 2092 } 2093 } else if (Kind == CK_BitCast) { 2094 checkCastAlign(); 2095 } 2096 2097 // Clear out SrcExpr if there was a fatal error. 2098 if (tcr != TC_Success) 2099 SrcExpr = ExprError(); 2100} 2101 2102/// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a 2103/// non-matching type. Such as enum function call to int, int call to 2104/// pointer; etc. Cast to 'void' is an exception. 2105static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr, 2106 QualType DestType) { 2107 if (Self.Diags.getDiagnosticLevel(diag::warn_bad_function_cast, 2108 SrcExpr.get()->getExprLoc()) 2109 == DiagnosticsEngine::Ignored) 2110 return; 2111 2112 if (!isa<CallExpr>(SrcExpr.get())) 2113 return; 2114 2115 QualType SrcType = SrcExpr.get()->getType(); 2116 if (DestType.getUnqualifiedType()->isVoidType()) 2117 return; 2118 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType()) 2119 && (DestType->isAnyPointerType() || DestType->isBlockPointerType())) 2120 return; 2121 if (SrcType->isIntegerType() && DestType->isIntegerType() && 2122 (SrcType->isBooleanType() == DestType->isBooleanType()) && 2123 (SrcType->isEnumeralType() == DestType->isEnumeralType())) 2124 return; 2125 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType()) 2126 return; 2127 if (SrcType->isEnumeralType() && DestType->isEnumeralType()) 2128 return; 2129 if (SrcType->isComplexType() && DestType->isComplexType()) 2130 return; 2131 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType()) 2132 return; 2133 2134 Self.Diag(SrcExpr.get()->getExprLoc(), 2135 diag::warn_bad_function_cast) 2136 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2137} 2138 2139/// Check the semantics of a C-style cast operation, in C. 2140void CastOperation::CheckCStyleCast() { 2141 assert(!Self.getLangOpts().CPlusPlus); 2142 2143 // C-style casts can resolve __unknown_any types. 2144 if (claimPlaceholder(BuiltinType::UnknownAny)) { 2145 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 2146 SrcExpr.get(), Kind, 2147 ValueKind, BasePath); 2148 return; 2149 } 2150 2151 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression 2152 // type needs to be scalar. 2153 if (DestType->isVoidType()) { 2154 // We don't necessarily do lvalue-to-rvalue conversions on this. 2155 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 2156 if (SrcExpr.isInvalid()) 2157 return; 2158 2159 // Cast to void allows any expr type. 2160 Kind = CK_ToVoid; 2161 return; 2162 } 2163 2164 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 2165 if (SrcExpr.isInvalid()) 2166 return; 2167 QualType SrcType = SrcExpr.get()->getType(); 2168 2169 assert(!SrcType->isPlaceholderType()); 2170 2171 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 2172 diag::err_typecheck_cast_to_incomplete)) { 2173 SrcExpr = ExprError(); 2174 return; 2175 } 2176 2177 if (!DestType->isScalarType() && !DestType->isVectorType()) { 2178 const RecordType *DestRecordTy = DestType->getAs<RecordType>(); 2179 2180 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){ 2181 // GCC struct/union extension: allow cast to self. 2182 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar) 2183 << DestType << SrcExpr.get()->getSourceRange(); 2184 Kind = CK_NoOp; 2185 return; 2186 } 2187 2188 // GCC's cast to union extension. 2189 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) { 2190 RecordDecl *RD = DestRecordTy->getDecl(); 2191 RecordDecl::field_iterator Field, FieldEnd; 2192 for (Field = RD->field_begin(), FieldEnd = RD->field_end(); 2193 Field != FieldEnd; ++Field) { 2194 if (Self.Context.hasSameUnqualifiedType(Field->getType(), SrcType) && 2195 !Field->isUnnamedBitfield()) { 2196 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union) 2197 << SrcExpr.get()->getSourceRange(); 2198 break; 2199 } 2200 } 2201 if (Field == FieldEnd) { 2202 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type) 2203 << SrcType << SrcExpr.get()->getSourceRange(); 2204 SrcExpr = ExprError(); 2205 return; 2206 } 2207 Kind = CK_ToUnion; 2208 return; 2209 } 2210 2211 // Reject any other conversions to non-scalar types. 2212 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar) 2213 << DestType << SrcExpr.get()->getSourceRange(); 2214 SrcExpr = ExprError(); 2215 return; 2216 } 2217 2218 // The type we're casting to is known to be a scalar or vector. 2219 2220 // Require the operand to be a scalar or vector. 2221 if (!SrcType->isScalarType() && !SrcType->isVectorType()) { 2222 Self.Diag(SrcExpr.get()->getExprLoc(), 2223 diag::err_typecheck_expect_scalar_operand) 2224 << SrcType << SrcExpr.get()->getSourceRange(); 2225 SrcExpr = ExprError(); 2226 return; 2227 } 2228 2229 if (DestType->isExtVectorType()) { 2230 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.take(), Kind); 2231 return; 2232 } 2233 2234 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) { 2235 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector && 2236 (SrcType->isIntegerType() || SrcType->isFloatingType())) { 2237 Kind = CK_VectorSplat; 2238 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) { 2239 SrcExpr = ExprError(); 2240 } 2241 return; 2242 } 2243 2244 if (SrcType->isVectorType()) { 2245 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind)) 2246 SrcExpr = ExprError(); 2247 return; 2248 } 2249 2250 // The source and target types are both scalars, i.e. 2251 // - arithmetic types (fundamental, enum, and complex) 2252 // - all kinds of pointers 2253 // Note that member pointers were filtered out with C++, above. 2254 2255 if (isa<ObjCSelectorExpr>(SrcExpr.get())) { 2256 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr); 2257 SrcExpr = ExprError(); 2258 return; 2259 } 2260 2261 // If either type is a pointer, the other type has to be either an 2262 // integer or a pointer. 2263 if (!DestType->isArithmeticType()) { 2264 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) { 2265 Self.Diag(SrcExpr.get()->getExprLoc(), 2266 diag::err_cast_pointer_from_non_pointer_int) 2267 << SrcType << SrcExpr.get()->getSourceRange(); 2268 SrcExpr = ExprError(); 2269 return; 2270 } 2271 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(), 2272 DestType, Self); 2273 } else if (!SrcType->isArithmeticType()) { 2274 if (!DestType->isIntegralType(Self.Context) && 2275 DestType->isArithmeticType()) { 2276 Self.Diag(SrcExpr.get()->getLocStart(), 2277 diag::err_cast_pointer_to_non_pointer_int) 2278 << DestType << SrcExpr.get()->getSourceRange(); 2279 SrcExpr = ExprError(); 2280 return; 2281 } 2282 } 2283 2284 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().cl_khr_fp16) { 2285 if (DestType->isHalfType()) { 2286 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half) 2287 << DestType << SrcExpr.get()->getSourceRange(); 2288 SrcExpr = ExprError(); 2289 return; 2290 } 2291 } 2292 2293 // ARC imposes extra restrictions on casts. 2294 if (Self.getLangOpts().ObjCAutoRefCount) { 2295 checkObjCARCConversion(Sema::CCK_CStyleCast); 2296 if (SrcExpr.isInvalid()) 2297 return; 2298 2299 if (const PointerType *CastPtr = DestType->getAs<PointerType>()) { 2300 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) { 2301 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers(); 2302 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers(); 2303 if (CastPtr->getPointeeType()->isObjCLifetimeType() && 2304 ExprPtr->getPointeeType()->isObjCLifetimeType() && 2305 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) { 2306 Self.Diag(SrcExpr.get()->getLocStart(), 2307 diag::err_typecheck_incompatible_ownership) 2308 << SrcType << DestType << Sema::AA_Casting 2309 << SrcExpr.get()->getSourceRange(); 2310 return; 2311 } 2312 } 2313 } 2314 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) { 2315 Self.Diag(SrcExpr.get()->getLocStart(), 2316 diag::err_arc_convesion_of_weak_unavailable) 2317 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2318 SrcExpr = ExprError(); 2319 return; 2320 } 2321 } 2322 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 2323 DiagnoseBadFunctionCast(Self, SrcExpr, DestType); 2324 Kind = Self.PrepareScalarCast(SrcExpr, DestType); 2325 if (SrcExpr.isInvalid()) 2326 return; 2327 2328 if (Kind == CK_BitCast) 2329 checkCastAlign(); 2330} 2331 2332ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc, 2333 TypeSourceInfo *CastTypeInfo, 2334 SourceLocation RPLoc, 2335 Expr *CastExpr) { 2336 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2337 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2338 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd()); 2339 2340 if (getLangOpts().CPlusPlus) { 2341 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false, 2342 isa<InitListExpr>(CastExpr)); 2343 } else { 2344 Op.CheckCStyleCast(); 2345 } 2346 2347 if (Op.SrcExpr.isInvalid()) 2348 return ExprError(); 2349 2350 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType, 2351 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 2352 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc)); 2353} 2354 2355ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo, 2356 SourceLocation LPLoc, 2357 Expr *CastExpr, 2358 SourceLocation RPLoc) { 2359 assert(LPLoc.isValid() && "List-initialization shouldn't get here."); 2360 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2361 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2362 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd()); 2363 2364 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false); 2365 if (Op.SrcExpr.isInvalid()) 2366 return ExprError(); 2367 2368 if (CXXConstructExpr *ConstructExpr = dyn_cast<CXXConstructExpr>(Op.SrcExpr.get())) 2369 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc)); 2370 2371 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType, 2372 Op.ValueKind, CastTypeInfo, Op.Kind, 2373 Op.SrcExpr.take(), &Op.BasePath, LPLoc, RPLoc)); 2374} 2375