SemaCast.cpp revision 1f78a50f8aee58f8e07f6307f4b8d0b1742e9a2b
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, Expr *SrcExpr, QualType DestType, 204 bool CStyle, unsigned &msg); 205static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 206 QualType DestType, bool CStyle, 207 const SourceRange &OpRange, 208 unsigned &msg, 209 CastKind &Kind); 210 211 212/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's. 213ExprResult 214Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 215 SourceLocation LAngleBracketLoc, Declarator &D, 216 SourceLocation RAngleBracketLoc, 217 SourceLocation LParenLoc, Expr *E, 218 SourceLocation RParenLoc) { 219 220 assert(!D.isInvalidType()); 221 222 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType()); 223 if (D.isInvalidType()) 224 return ExprError(); 225 226 if (getLangOpts().CPlusPlus) { 227 // Check that there are no default arguments (C++ only). 228 CheckExtraCXXDefaultArguments(D); 229 } 230 231 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E, 232 SourceRange(LAngleBracketLoc, RAngleBracketLoc), 233 SourceRange(LParenLoc, RParenLoc)); 234} 235 236ExprResult 237Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 238 TypeSourceInfo *DestTInfo, Expr *E, 239 SourceRange AngleBrackets, SourceRange Parens) { 240 ExprResult Ex = Owned(E); 241 QualType DestType = DestTInfo->getType(); 242 243 // If the type is dependent, we won't do the semantic analysis now. 244 // FIXME: should we check this in a more fine-grained manner? 245 bool TypeDependent = DestType->isDependentType() || Ex.get()->isTypeDependent(); 246 247 CastOperation Op(*this, DestType, E); 248 Op.OpRange = SourceRange(OpLoc, Parens.getEnd()); 249 Op.DestRange = AngleBrackets; 250 251 switch (Kind) { 252 default: llvm_unreachable("Unknown C++ cast!"); 253 254 case tok::kw_const_cast: 255 if (!TypeDependent) { 256 Op.CheckConstCast(); 257 if (Op.SrcExpr.isInvalid()) 258 return ExprError(); 259 } 260 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType, 261 Op.ValueKind, Op.SrcExpr.take(), DestTInfo, 262 OpLoc, Parens.getEnd(), 263 AngleBrackets)); 264 265 case tok::kw_dynamic_cast: { 266 if (!TypeDependent) { 267 Op.CheckDynamicCast(); 268 if (Op.SrcExpr.isInvalid()) 269 return ExprError(); 270 } 271 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType, 272 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 273 &Op.BasePath, DestTInfo, 274 OpLoc, Parens.getEnd(), 275 AngleBrackets)); 276 } 277 case tok::kw_reinterpret_cast: { 278 if (!TypeDependent) { 279 Op.CheckReinterpretCast(); 280 if (Op.SrcExpr.isInvalid()) 281 return ExprError(); 282 } 283 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType, 284 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 285 0, DestTInfo, OpLoc, 286 Parens.getEnd(), 287 AngleBrackets)); 288 } 289 case tok::kw_static_cast: { 290 if (!TypeDependent) { 291 Op.CheckStaticCast(); 292 if (Op.SrcExpr.isInvalid()) 293 return ExprError(); 294 } 295 296 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType, 297 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 298 &Op.BasePath, DestTInfo, 299 OpLoc, Parens.getEnd(), 300 AngleBrackets)); 301 } 302 } 303} 304 305/// Try to diagnose a failed overloaded cast. Returns true if 306/// diagnostics were emitted. 307static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT, 308 SourceRange range, Expr *src, 309 QualType destType, 310 bool listInitialization) { 311 switch (CT) { 312 // These cast kinds don't consider user-defined conversions. 313 case CT_Const: 314 case CT_Reinterpret: 315 case CT_Dynamic: 316 return false; 317 318 // These do. 319 case CT_Static: 320 case CT_CStyle: 321 case CT_Functional: 322 break; 323 } 324 325 QualType srcType = src->getType(); 326 if (!destType->isRecordType() && !srcType->isRecordType()) 327 return false; 328 329 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType); 330 InitializationKind initKind 331 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(), 332 range, listInitialization) 333 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range, 334 listInitialization) 335 : InitializationKind::CreateCast(/*type range?*/ range); 336 InitializationSequence sequence(S, entity, initKind, src); 337 338 assert(sequence.Failed() && "initialization succeeded on second try?"); 339 switch (sequence.getFailureKind()) { 340 default: return false; 341 342 case InitializationSequence::FK_ConstructorOverloadFailed: 343 case InitializationSequence::FK_UserConversionOverloadFailed: 344 break; 345 } 346 347 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet(); 348 349 unsigned msg = 0; 350 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates; 351 352 switch (sequence.getFailedOverloadResult()) { 353 case OR_Success: llvm_unreachable("successful failed overload"); 354 case OR_No_Viable_Function: 355 if (candidates.empty()) 356 msg = diag::err_ovl_no_conversion_in_cast; 357 else 358 msg = diag::err_ovl_no_viable_conversion_in_cast; 359 howManyCandidates = OCD_AllCandidates; 360 break; 361 362 case OR_Ambiguous: 363 msg = diag::err_ovl_ambiguous_conversion_in_cast; 364 howManyCandidates = OCD_ViableCandidates; 365 break; 366 367 case OR_Deleted: 368 msg = diag::err_ovl_deleted_conversion_in_cast; 369 howManyCandidates = OCD_ViableCandidates; 370 break; 371 } 372 373 S.Diag(range.getBegin(), msg) 374 << CT << srcType << destType 375 << range << src->getSourceRange(); 376 377 candidates.NoteCandidates(S, howManyCandidates, src); 378 379 return true; 380} 381 382/// Diagnose a failed cast. 383static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType, 384 SourceRange opRange, Expr *src, QualType destType, 385 bool listInitialization) { 386 if (src->getType() == S.Context.BoundMemberTy) { 387 (void) S.CheckPlaceholderExpr(src); // will always fail 388 return; 389 } 390 391 if (msg == diag::err_bad_cxx_cast_generic && 392 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType, 393 listInitialization)) 394 return; 395 396 S.Diag(opRange.getBegin(), msg) << castType 397 << src->getType() << destType << opRange << src->getSourceRange(); 398} 399 400/// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes, 401/// this removes one level of indirection from both types, provided that they're 402/// the same kind of pointer (plain or to-member). Unlike the Sema function, 403/// this one doesn't care if the two pointers-to-member don't point into the 404/// same class. This is because CastsAwayConstness doesn't care. 405static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) { 406 const PointerType *T1PtrType = T1->getAs<PointerType>(), 407 *T2PtrType = T2->getAs<PointerType>(); 408 if (T1PtrType && T2PtrType) { 409 T1 = T1PtrType->getPointeeType(); 410 T2 = T2PtrType->getPointeeType(); 411 return true; 412 } 413 const ObjCObjectPointerType *T1ObjCPtrType = 414 T1->getAs<ObjCObjectPointerType>(), 415 *T2ObjCPtrType = 416 T2->getAs<ObjCObjectPointerType>(); 417 if (T1ObjCPtrType) { 418 if (T2ObjCPtrType) { 419 T1 = T1ObjCPtrType->getPointeeType(); 420 T2 = T2ObjCPtrType->getPointeeType(); 421 return true; 422 } 423 else if (T2PtrType) { 424 T1 = T1ObjCPtrType->getPointeeType(); 425 T2 = T2PtrType->getPointeeType(); 426 return true; 427 } 428 } 429 else if (T2ObjCPtrType) { 430 if (T1PtrType) { 431 T2 = T2ObjCPtrType->getPointeeType(); 432 T1 = T1PtrType->getPointeeType(); 433 return true; 434 } 435 } 436 437 const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(), 438 *T2MPType = T2->getAs<MemberPointerType>(); 439 if (T1MPType && T2MPType) { 440 T1 = T1MPType->getPointeeType(); 441 T2 = T2MPType->getPointeeType(); 442 return true; 443 } 444 445 const BlockPointerType *T1BPType = T1->getAs<BlockPointerType>(), 446 *T2BPType = T2->getAs<BlockPointerType>(); 447 if (T1BPType && T2BPType) { 448 T1 = T1BPType->getPointeeType(); 449 T2 = T2BPType->getPointeeType(); 450 return true; 451 } 452 453 return false; 454} 455 456/// CastsAwayConstness - Check if the pointer conversion from SrcType to 457/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by 458/// the cast checkers. Both arguments must denote pointer (possibly to member) 459/// types. 460/// 461/// \param CheckCVR Whether to check for const/volatile/restrict qualifiers. 462/// 463/// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers. 464static bool 465CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, 466 bool CheckCVR, bool CheckObjCLifetime) { 467 // If the only checking we care about is for Objective-C lifetime qualifiers, 468 // and we're not in ARC mode, there's nothing to check. 469 if (!CheckCVR && CheckObjCLifetime && 470 !Self.Context.getLangOpts().ObjCAutoRefCount) 471 return false; 472 473 // Casting away constness is defined in C++ 5.2.11p8 with reference to 474 // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since 475 // the rules are non-trivial. So first we construct Tcv *...cv* as described 476 // in C++ 5.2.11p8. 477 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() || 478 SrcType->isBlockPointerType()) && 479 "Source type is not pointer or pointer to member."); 480 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() || 481 DestType->isBlockPointerType()) && 482 "Destination type is not pointer or pointer to member."); 483 484 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType), 485 UnwrappedDestType = Self.Context.getCanonicalType(DestType); 486 SmallVector<Qualifiers, 8> cv1, cv2; 487 488 // Find the qualifiers. We only care about cvr-qualifiers for the 489 // purpose of this check, because other qualifiers (address spaces, 490 // Objective-C GC, etc.) are part of the type's identity. 491 while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) { 492 // Determine the relevant qualifiers at this level. 493 Qualifiers SrcQuals, DestQuals; 494 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals); 495 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals); 496 497 Qualifiers RetainedSrcQuals, RetainedDestQuals; 498 if (CheckCVR) { 499 RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers()); 500 RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers()); 501 } 502 503 if (CheckObjCLifetime && 504 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals)) 505 return true; 506 507 cv1.push_back(RetainedSrcQuals); 508 cv2.push_back(RetainedDestQuals); 509 } 510 if (cv1.empty()) 511 return false; 512 513 // Construct void pointers with those qualifiers (in reverse order of 514 // unwrapping, of course). 515 QualType SrcConstruct = Self.Context.VoidTy; 516 QualType DestConstruct = Self.Context.VoidTy; 517 ASTContext &Context = Self.Context; 518 for (SmallVector<Qualifiers, 8>::reverse_iterator i1 = cv1.rbegin(), 519 i2 = cv2.rbegin(); 520 i1 != cv1.rend(); ++i1, ++i2) { 521 SrcConstruct 522 = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1)); 523 DestConstruct 524 = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2)); 525 } 526 527 // Test if they're compatible. 528 bool ObjCLifetimeConversion; 529 return SrcConstruct != DestConstruct && 530 !Self.IsQualificationConversion(SrcConstruct, DestConstruct, false, 531 ObjCLifetimeConversion); 532} 533 534/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid. 535/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime- 536/// checked downcasts in class hierarchies. 537void CastOperation::CheckDynamicCast() { 538 if (ValueKind == VK_RValue) 539 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 540 else if (isPlaceholder()) 541 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.take()); 542 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 543 return; 544 545 QualType OrigSrcType = SrcExpr.get()->getType(); 546 QualType DestType = Self.Context.getCanonicalType(this->DestType); 547 548 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type, 549 // or "pointer to cv void". 550 551 QualType DestPointee; 552 const PointerType *DestPointer = DestType->getAs<PointerType>(); 553 const ReferenceType *DestReference = 0; 554 if (DestPointer) { 555 DestPointee = DestPointer->getPointeeType(); 556 } else if ((DestReference = DestType->getAs<ReferenceType>())) { 557 DestPointee = DestReference->getPointeeType(); 558 } else { 559 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr) 560 << this->DestType << DestRange; 561 return; 562 } 563 564 const RecordType *DestRecord = DestPointee->getAs<RecordType>(); 565 if (DestPointee->isVoidType()) { 566 assert(DestPointer && "Reference to void is not possible"); 567 } else if (DestRecord) { 568 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, 569 diag::err_bad_dynamic_cast_incomplete, 570 DestRange)) 571 return; 572 } else { 573 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 574 << DestPointee.getUnqualifiedType() << DestRange; 575 return; 576 } 577 578 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to 579 // complete class type, [...]. If T is an lvalue reference type, v shall be 580 // an lvalue of a complete class type, [...]. If T is an rvalue reference 581 // type, v shall be an expression having a complete class type, [...] 582 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType); 583 QualType SrcPointee; 584 if (DestPointer) { 585 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 586 SrcPointee = SrcPointer->getPointeeType(); 587 } else { 588 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr) 589 << OrigSrcType << SrcExpr.get()->getSourceRange(); 590 return; 591 } 592 } else if (DestReference->isLValueReferenceType()) { 593 if (!SrcExpr.get()->isLValue()) { 594 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue) 595 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 596 } 597 SrcPointee = SrcType; 598 } else { 599 SrcPointee = SrcType; 600 } 601 602 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>(); 603 if (SrcRecord) { 604 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee, 605 diag::err_bad_dynamic_cast_incomplete, 606 SrcExpr.get())) 607 return; 608 } else { 609 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 610 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 611 return; 612 } 613 614 assert((DestPointer || DestReference) && 615 "Bad destination non-ptr/ref slipped through."); 616 assert((DestRecord || DestPointee->isVoidType()) && 617 "Bad destination pointee slipped through."); 618 assert(SrcRecord && "Bad source pointee slipped through."); 619 620 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness. 621 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) { 622 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away) 623 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 624 return; 625 } 626 627 // C++ 5.2.7p3: If the type of v is the same as the required result type, 628 // [except for cv]. 629 if (DestRecord == SrcRecord) { 630 Kind = CK_NoOp; 631 return; 632 } 633 634 // C++ 5.2.7p5 635 // Upcasts are resolved statically. 636 if (DestRecord && Self.IsDerivedFrom(SrcPointee, DestPointee)) { 637 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee, 638 OpRange.getBegin(), OpRange, 639 &BasePath)) 640 return; 641 642 Kind = CK_DerivedToBase; 643 644 // If we are casting to or through a virtual base class, we need a 645 // vtable. 646 if (Self.BasePathInvolvesVirtualBase(BasePath)) 647 Self.MarkVTableUsed(OpRange.getBegin(), 648 cast<CXXRecordDecl>(SrcRecord->getDecl())); 649 return; 650 } 651 652 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic]. 653 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition(); 654 assert(SrcDecl && "Definition missing"); 655 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) { 656 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic) 657 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 658 } 659 Self.MarkVTableUsed(OpRange.getBegin(), 660 cast<CXXRecordDecl>(SrcRecord->getDecl())); 661 662 // Done. Everything else is run-time checks. 663 Kind = CK_Dynamic; 664} 665 666/// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid. 667/// Refer to C++ 5.2.11 for details. const_cast is typically used in code 668/// like this: 669/// const char *str = "literal"; 670/// legacy_function(const_cast\<char*\>(str)); 671void CastOperation::CheckConstCast() { 672 if (ValueKind == VK_RValue) 673 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 674 else if (isPlaceholder()) 675 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.take()); 676 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 677 return; 678 679 unsigned msg = diag::err_bad_cxx_cast_generic; 680 if (TryConstCast(Self, SrcExpr.get(), DestType, /*CStyle*/false, msg) != TC_Success 681 && msg != 0) 682 Self.Diag(OpRange.getBegin(), msg) << CT_Const 683 << SrcExpr.get()->getType() << DestType << OpRange; 684} 685 686/// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast 687/// or downcast between respective pointers or references. 688static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr, 689 QualType DestType, 690 SourceRange OpRange) { 691 QualType SrcType = SrcExpr->getType(); 692 // When casting from pointer or reference, get pointee type; use original 693 // type otherwise. 694 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl(); 695 const CXXRecordDecl *SrcRD = 696 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl(); 697 698 // Examining subobjects for records is only possible if the complete and 699 // valid definition is available. Also, template instantiation is not 700 // allowed here. 701 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl()) 702 return; 703 704 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl(); 705 706 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl()) 707 return; 708 709 enum { 710 ReinterpretUpcast, 711 ReinterpretDowncast 712 } ReinterpretKind; 713 714 CXXBasePaths BasePaths; 715 716 if (SrcRD->isDerivedFrom(DestRD, BasePaths)) 717 ReinterpretKind = ReinterpretUpcast; 718 else if (DestRD->isDerivedFrom(SrcRD, BasePaths)) 719 ReinterpretKind = ReinterpretDowncast; 720 else 721 return; 722 723 bool VirtualBase = true; 724 bool NonZeroOffset = false; 725 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(), 726 E = BasePaths.end(); 727 I != E; ++I) { 728 const CXXBasePath &Path = *I; 729 CharUnits Offset = CharUnits::Zero(); 730 bool IsVirtual = false; 731 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end(); 732 IElem != EElem; ++IElem) { 733 IsVirtual = IElem->Base->isVirtual(); 734 if (IsVirtual) 735 break; 736 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl(); 737 assert(BaseRD && "Base type should be a valid unqualified class type"); 738 // Don't check if any base has invalid declaration or has no definition 739 // since it has no layout info. 740 const CXXRecordDecl *Class = IElem->Class, 741 *ClassDefinition = Class->getDefinition(); 742 if (Class->isInvalidDecl() || !ClassDefinition || 743 !ClassDefinition->isCompleteDefinition()) 744 return; 745 746 const ASTRecordLayout &DerivedLayout = 747 Self.Context.getASTRecordLayout(Class); 748 Offset += DerivedLayout.getBaseClassOffset(BaseRD); 749 } 750 if (!IsVirtual) { 751 // Don't warn if any path is a non-virtually derived base at offset zero. 752 if (Offset.isZero()) 753 return; 754 // Offset makes sense only for non-virtual bases. 755 else 756 NonZeroOffset = true; 757 } 758 VirtualBase = VirtualBase && IsVirtual; 759 } 760 761 assert((VirtualBase || NonZeroOffset) && 762 "Should have returned if has non-virtual base with zero offset"); 763 764 QualType BaseType = 765 ReinterpretKind == ReinterpretUpcast? DestType : SrcType; 766 QualType DerivedType = 767 ReinterpretKind == ReinterpretUpcast? SrcType : DestType; 768 769 SourceLocation BeginLoc = OpRange.getBegin(); 770 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static) 771 << DerivedType << BaseType << !VirtualBase << ReinterpretKind 772 << OpRange; 773 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static) 774 << ReinterpretKind 775 << FixItHint::CreateReplacement(BeginLoc, "static_cast"); 776} 777 778/// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is 779/// valid. 780/// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code 781/// like this: 782/// char *bytes = reinterpret_cast\<char*\>(int_ptr); 783void CastOperation::CheckReinterpretCast() { 784 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload)) 785 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 786 else 787 checkNonOverloadPlaceholders(); 788 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 789 return; 790 791 unsigned msg = diag::err_bad_cxx_cast_generic; 792 TryCastResult tcr = 793 TryReinterpretCast(Self, SrcExpr, DestType, 794 /*CStyle*/false, OpRange, msg, Kind); 795 if (tcr != TC_Success && msg != 0) 796 { 797 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 798 return; 799 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 800 //FIXME: &f<int>; is overloaded and resolvable 801 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload) 802 << OverloadExpr::find(SrcExpr.get()).Expression->getName() 803 << DestType << OpRange; 804 Self.NoteAllOverloadCandidates(SrcExpr.get()); 805 806 } else { 807 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(), 808 DestType, /*listInitialization=*/false); 809 } 810 } else if (tcr == TC_Success) { 811 if (Self.getLangOpts().ObjCAutoRefCount) 812 checkObjCARCConversion(Sema::CCK_OtherCast); 813 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange); 814 } 815} 816 817 818/// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid. 819/// Refer to C++ 5.2.9 for details. Static casts are mostly used for making 820/// implicit conversions explicit and getting rid of data loss warnings. 821void CastOperation::CheckStaticCast() { 822 if (isPlaceholder()) { 823 checkNonOverloadPlaceholders(); 824 if (SrcExpr.isInvalid()) 825 return; 826 } 827 828 // This test is outside everything else because it's the only case where 829 // a non-lvalue-reference target type does not lead to decay. 830 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 831 if (DestType->isVoidType()) { 832 Kind = CK_ToVoid; 833 834 if (claimPlaceholder(BuiltinType::Overload)) { 835 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr, 836 false, // Decay Function to ptr 837 true, // Complain 838 OpRange, DestType, diag::err_bad_static_cast_overload); 839 if (SrcExpr.isInvalid()) 840 return; 841 } 842 843 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 844 return; 845 } 846 847 if (ValueKind == VK_RValue && !DestType->isRecordType() && 848 !isPlaceholder(BuiltinType::Overload)) { 849 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 850 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 851 return; 852 } 853 854 unsigned msg = diag::err_bad_cxx_cast_generic; 855 TryCastResult tcr 856 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg, 857 Kind, BasePath, /*ListInitialization=*/false); 858 if (tcr != TC_Success && msg != 0) { 859 if (SrcExpr.isInvalid()) 860 return; 861 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 862 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression; 863 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload) 864 << oe->getName() << DestType << OpRange 865 << oe->getQualifierLoc().getSourceRange(); 866 Self.NoteAllOverloadCandidates(SrcExpr.get()); 867 } else { 868 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType, 869 /*listInitialization=*/false); 870 } 871 } else if (tcr == TC_Success) { 872 if (Kind == CK_BitCast) 873 checkCastAlign(); 874 if (Self.getLangOpts().ObjCAutoRefCount) 875 checkObjCARCConversion(Sema::CCK_OtherCast); 876 } else if (Kind == CK_BitCast) { 877 checkCastAlign(); 878 } 879} 880 881/// TryStaticCast - Check if a static cast can be performed, and do so if 882/// possible. If @p CStyle, ignore access restrictions on hierarchy casting 883/// and casting away constness. 884static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, 885 QualType DestType, 886 Sema::CheckedConversionKind CCK, 887 const SourceRange &OpRange, unsigned &msg, 888 CastKind &Kind, CXXCastPath &BasePath, 889 bool ListInitialization) { 890 // Determine whether we have the semantics of a C-style cast. 891 bool CStyle 892 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 893 894 // The order the tests is not entirely arbitrary. There is one conversion 895 // that can be handled in two different ways. Given: 896 // struct A {}; 897 // struct B : public A { 898 // B(); B(const A&); 899 // }; 900 // const A &a = B(); 901 // the cast static_cast<const B&>(a) could be seen as either a static 902 // reference downcast, or an explicit invocation of the user-defined 903 // conversion using B's conversion constructor. 904 // DR 427 specifies that the downcast is to be applied here. 905 906 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 907 // Done outside this function. 908 909 TryCastResult tcr; 910 911 // C++ 5.2.9p5, reference downcast. 912 // See the function for details. 913 // DR 427 specifies that this is to be applied before paragraph 2. 914 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle, 915 OpRange, msg, Kind, BasePath); 916 if (tcr != TC_NotApplicable) 917 return tcr; 918 919 // C++0x [expr.static.cast]p3: 920 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2 921 // T2" if "cv2 T2" is reference-compatible with "cv1 T1". 922 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind, 923 BasePath, msg); 924 if (tcr != TC_NotApplicable) 925 return tcr; 926 927 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T 928 // [...] if the declaration "T t(e);" is well-formed, [...]. 929 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg, 930 Kind, ListInitialization); 931 if (SrcExpr.isInvalid()) 932 return TC_Failed; 933 if (tcr != TC_NotApplicable) 934 return tcr; 935 936 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except 937 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean 938 // conversions, subject to further restrictions. 939 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal 940 // of qualification conversions impossible. 941 // In the CStyle case, the earlier attempt to const_cast should have taken 942 // care of reverse qualification conversions. 943 944 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType()); 945 946 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly 947 // converted to an integral type. [...] A value of a scoped enumeration type 948 // can also be explicitly converted to a floating-point type [...]. 949 if (const EnumType *Enum = SrcType->getAs<EnumType>()) { 950 if (Enum->getDecl()->isScoped()) { 951 if (DestType->isBooleanType()) { 952 Kind = CK_IntegralToBoolean; 953 return TC_Success; 954 } else if (DestType->isIntegralType(Self.Context)) { 955 Kind = CK_IntegralCast; 956 return TC_Success; 957 } else if (DestType->isRealFloatingType()) { 958 Kind = CK_IntegralToFloating; 959 return TC_Success; 960 } 961 } 962 } 963 964 // Reverse integral promotion/conversion. All such conversions are themselves 965 // again integral promotions or conversions and are thus already handled by 966 // p2 (TryDirectInitialization above). 967 // (Note: any data loss warnings should be suppressed.) 968 // The exception is the reverse of enum->integer, i.e. integer->enum (and 969 // enum->enum). See also C++ 5.2.9p7. 970 // The same goes for reverse floating point promotion/conversion and 971 // floating-integral conversions. Again, only floating->enum is relevant. 972 if (DestType->isEnumeralType()) { 973 if (SrcType->isIntegralOrEnumerationType()) { 974 Kind = CK_IntegralCast; 975 return TC_Success; 976 } else if (SrcType->isRealFloatingType()) { 977 Kind = CK_FloatingToIntegral; 978 return TC_Success; 979 } 980 } 981 982 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast. 983 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance. 984 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg, 985 Kind, BasePath); 986 if (tcr != TC_NotApplicable) 987 return tcr; 988 989 // Reverse member pointer conversion. C++ 4.11 specifies member pointer 990 // conversion. C++ 5.2.9p9 has additional information. 991 // DR54's access restrictions apply here also. 992 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle, 993 OpRange, msg, Kind, BasePath); 994 if (tcr != TC_NotApplicable) 995 return tcr; 996 997 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to 998 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is 999 // just the usual constness stuff. 1000 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 1001 QualType SrcPointee = SrcPointer->getPointeeType(); 1002 if (SrcPointee->isVoidType()) { 1003 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) { 1004 QualType DestPointee = DestPointer->getPointeeType(); 1005 if (DestPointee->isIncompleteOrObjectType()) { 1006 // This is definitely the intended conversion, but it might fail due 1007 // to a qualifier violation. Note that we permit Objective-C lifetime 1008 // and GC qualifier mismatches here. 1009 if (!CStyle) { 1010 Qualifiers DestPointeeQuals = DestPointee.getQualifiers(); 1011 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers(); 1012 DestPointeeQuals.removeObjCGCAttr(); 1013 DestPointeeQuals.removeObjCLifetime(); 1014 SrcPointeeQuals.removeObjCGCAttr(); 1015 SrcPointeeQuals.removeObjCLifetime(); 1016 if (DestPointeeQuals != SrcPointeeQuals && 1017 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) { 1018 msg = diag::err_bad_cxx_cast_qualifiers_away; 1019 return TC_Failed; 1020 } 1021 } 1022 Kind = CK_BitCast; 1023 return TC_Success; 1024 } 1025 } 1026 else if (DestType->isObjCObjectPointerType()) { 1027 // allow both c-style cast and static_cast of objective-c pointers as 1028 // they are pervasive. 1029 Kind = CK_CPointerToObjCPointerCast; 1030 return TC_Success; 1031 } 1032 else if (CStyle && DestType->isBlockPointerType()) { 1033 // allow c-style cast of void * to block pointers. 1034 Kind = CK_AnyPointerToBlockPointerCast; 1035 return TC_Success; 1036 } 1037 } 1038 } 1039 // Allow arbitray objective-c pointer conversion with static casts. 1040 if (SrcType->isObjCObjectPointerType() && 1041 DestType->isObjCObjectPointerType()) { 1042 Kind = CK_BitCast; 1043 return TC_Success; 1044 } 1045 1046 // We tried everything. Everything! Nothing works! :-( 1047 return TC_NotApplicable; 1048} 1049 1050/// Tests whether a conversion according to N2844 is valid. 1051TryCastResult 1052TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, QualType DestType, 1053 bool CStyle, CastKind &Kind, CXXCastPath &BasePath, 1054 unsigned &msg) { 1055 // C++0x [expr.static.cast]p3: 1056 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to 1057 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1". 1058 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>(); 1059 if (!R) 1060 return TC_NotApplicable; 1061 1062 if (!SrcExpr->isGLValue()) 1063 return TC_NotApplicable; 1064 1065 // Because we try the reference downcast before this function, from now on 1066 // this is the only cast possibility, so we issue an error if we fail now. 1067 // FIXME: Should allow casting away constness if CStyle. 1068 bool DerivedToBase; 1069 bool ObjCConversion; 1070 bool ObjCLifetimeConversion; 1071 QualType FromType = SrcExpr->getType(); 1072 QualType ToType = R->getPointeeType(); 1073 if (CStyle) { 1074 FromType = FromType.getUnqualifiedType(); 1075 ToType = ToType.getUnqualifiedType(); 1076 } 1077 1078 if (Self.CompareReferenceRelationship(SrcExpr->getLocStart(), 1079 ToType, FromType, 1080 DerivedToBase, ObjCConversion, 1081 ObjCLifetimeConversion) 1082 < Sema::Ref_Compatible_With_Added_Qualification) { 1083 msg = diag::err_bad_lvalue_to_rvalue_cast; 1084 return TC_Failed; 1085 } 1086 1087 if (DerivedToBase) { 1088 Kind = CK_DerivedToBase; 1089 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1090 /*DetectVirtual=*/true); 1091 if (!Self.IsDerivedFrom(SrcExpr->getType(), R->getPointeeType(), Paths)) 1092 return TC_NotApplicable; 1093 1094 Self.BuildBasePathArray(Paths, BasePath); 1095 } else 1096 Kind = CK_NoOp; 1097 1098 return TC_Success; 1099} 1100 1101/// Tests whether a conversion according to C++ 5.2.9p5 is valid. 1102TryCastResult 1103TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType, 1104 bool CStyle, const SourceRange &OpRange, 1105 unsigned &msg, CastKind &Kind, 1106 CXXCastPath &BasePath) { 1107 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be 1108 // cast to type "reference to cv2 D", where D is a class derived from B, 1109 // if a valid standard conversion from "pointer to D" to "pointer to B" 1110 // exists, cv2 >= cv1, and B is not a virtual base class of D. 1111 // In addition, DR54 clarifies that the base must be accessible in the 1112 // current context. Although the wording of DR54 only applies to the pointer 1113 // variant of this rule, the intent is clearly for it to apply to the this 1114 // conversion as well. 1115 1116 const ReferenceType *DestReference = DestType->getAs<ReferenceType>(); 1117 if (!DestReference) { 1118 return TC_NotApplicable; 1119 } 1120 bool RValueRef = DestReference->isRValueReferenceType(); 1121 if (!RValueRef && !SrcExpr->isLValue()) { 1122 // We know the left side is an lvalue reference, so we can suggest a reason. 1123 msg = diag::err_bad_cxx_cast_rvalue; 1124 return TC_NotApplicable; 1125 } 1126 1127 QualType DestPointee = DestReference->getPointeeType(); 1128 1129 return TryStaticDowncast(Self, 1130 Self.Context.getCanonicalType(SrcExpr->getType()), 1131 Self.Context.getCanonicalType(DestPointee), CStyle, 1132 OpRange, SrcExpr->getType(), DestType, msg, Kind, 1133 BasePath); 1134} 1135 1136/// Tests whether a conversion according to C++ 5.2.9p8 is valid. 1137TryCastResult 1138TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType, 1139 bool CStyle, const SourceRange &OpRange, 1140 unsigned &msg, CastKind &Kind, 1141 CXXCastPath &BasePath) { 1142 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class 1143 // type, can be converted to an rvalue of type "pointer to cv2 D", where D 1144 // is a class derived from B, if a valid standard conversion from "pointer 1145 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base 1146 // class of D. 1147 // In addition, DR54 clarifies that the base must be accessible in the 1148 // current context. 1149 1150 const PointerType *DestPointer = DestType->getAs<PointerType>(); 1151 if (!DestPointer) { 1152 return TC_NotApplicable; 1153 } 1154 1155 const PointerType *SrcPointer = SrcType->getAs<PointerType>(); 1156 if (!SrcPointer) { 1157 msg = diag::err_bad_static_cast_pointer_nonpointer; 1158 return TC_NotApplicable; 1159 } 1160 1161 return TryStaticDowncast(Self, 1162 Self.Context.getCanonicalType(SrcPointer->getPointeeType()), 1163 Self.Context.getCanonicalType(DestPointer->getPointeeType()), 1164 CStyle, OpRange, SrcType, DestType, msg, Kind, 1165 BasePath); 1166} 1167 1168/// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and 1169/// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to 1170/// DestType is possible and allowed. 1171TryCastResult 1172TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType, 1173 bool CStyle, const SourceRange &OpRange, QualType OrigSrcType, 1174 QualType OrigDestType, unsigned &msg, 1175 CastKind &Kind, CXXCastPath &BasePath) { 1176 // We can only work with complete types. But don't complain if it doesn't work 1177 if (Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0) || 1178 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0)) 1179 return TC_NotApplicable; 1180 1181 // Downcast can only happen in class hierarchies, so we need classes. 1182 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) { 1183 return TC_NotApplicable; 1184 } 1185 1186 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1187 /*DetectVirtual=*/true); 1188 if (!Self.IsDerivedFrom(DestType, SrcType, Paths)) { 1189 return TC_NotApplicable; 1190 } 1191 1192 // Target type does derive from source type. Now we're serious. If an error 1193 // appears now, it's not ignored. 1194 // This may not be entirely in line with the standard. Take for example: 1195 // struct A {}; 1196 // struct B : virtual A { 1197 // B(A&); 1198 // }; 1199 // 1200 // void f() 1201 // { 1202 // (void)static_cast<const B&>(*((A*)0)); 1203 // } 1204 // As far as the standard is concerned, p5 does not apply (A is virtual), so 1205 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid. 1206 // However, both GCC and Comeau reject this example, and accepting it would 1207 // mean more complex code if we're to preserve the nice error message. 1208 // FIXME: Being 100% compliant here would be nice to have. 1209 1210 // Must preserve cv, as always, unless we're in C-style mode. 1211 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) { 1212 msg = diag::err_bad_cxx_cast_qualifiers_away; 1213 return TC_Failed; 1214 } 1215 1216 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) { 1217 // This code is analoguous to that in CheckDerivedToBaseConversion, except 1218 // that it builds the paths in reverse order. 1219 // To sum up: record all paths to the base and build a nice string from 1220 // them. Use it to spice up the error message. 1221 if (!Paths.isRecordingPaths()) { 1222 Paths.clear(); 1223 Paths.setRecordingPaths(true); 1224 Self.IsDerivedFrom(DestType, SrcType, Paths); 1225 } 1226 std::string PathDisplayStr; 1227 std::set<unsigned> DisplayedPaths; 1228 for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end(); 1229 PI != PE; ++PI) { 1230 if (DisplayedPaths.insert(PI->back().SubobjectNumber).second) { 1231 // We haven't displayed a path to this particular base 1232 // class subobject yet. 1233 PathDisplayStr += "\n "; 1234 for (CXXBasePath::const_reverse_iterator EI = PI->rbegin(), 1235 EE = PI->rend(); 1236 EI != EE; ++EI) 1237 PathDisplayStr += EI->Base->getType().getAsString() + " -> "; 1238 PathDisplayStr += QualType(DestType).getAsString(); 1239 } 1240 } 1241 1242 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast) 1243 << QualType(SrcType).getUnqualifiedType() 1244 << QualType(DestType).getUnqualifiedType() 1245 << PathDisplayStr << OpRange; 1246 msg = 0; 1247 return TC_Failed; 1248 } 1249 1250 if (Paths.getDetectedVirtual() != 0) { 1251 QualType VirtualBase(Paths.getDetectedVirtual(), 0); 1252 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual) 1253 << OrigSrcType << OrigDestType << VirtualBase << OpRange; 1254 msg = 0; 1255 return TC_Failed; 1256 } 1257 1258 if (!CStyle) { 1259 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1260 SrcType, DestType, 1261 Paths.front(), 1262 diag::err_downcast_from_inaccessible_base)) { 1263 case Sema::AR_accessible: 1264 case Sema::AR_delayed: // be optimistic 1265 case Sema::AR_dependent: // be optimistic 1266 break; 1267 1268 case Sema::AR_inaccessible: 1269 msg = 0; 1270 return TC_Failed; 1271 } 1272 } 1273 1274 Self.BuildBasePathArray(Paths, BasePath); 1275 Kind = CK_BaseToDerived; 1276 return TC_Success; 1277} 1278 1279/// TryStaticMemberPointerUpcast - Tests whether a conversion according to 1280/// C++ 5.2.9p9 is valid: 1281/// 1282/// An rvalue of type "pointer to member of D of type cv1 T" can be 1283/// converted to an rvalue of type "pointer to member of B of type cv2 T", 1284/// where B is a base class of D [...]. 1285/// 1286TryCastResult 1287TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType, 1288 QualType DestType, bool CStyle, 1289 const SourceRange &OpRange, 1290 unsigned &msg, CastKind &Kind, 1291 CXXCastPath &BasePath) { 1292 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(); 1293 if (!DestMemPtr) 1294 return TC_NotApplicable; 1295 1296 bool WasOverloadedFunction = false; 1297 DeclAccessPair FoundOverload; 1298 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 1299 if (FunctionDecl *Fn 1300 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false, 1301 FoundOverload)) { 1302 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 1303 SrcType = Self.Context.getMemberPointerType(Fn->getType(), 1304 Self.Context.getTypeDeclType(M->getParent()).getTypePtr()); 1305 WasOverloadedFunction = true; 1306 } 1307 } 1308 1309 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1310 if (!SrcMemPtr) { 1311 msg = diag::err_bad_static_cast_member_pointer_nonmp; 1312 return TC_NotApplicable; 1313 } 1314 1315 // T == T, modulo cv 1316 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(), 1317 DestMemPtr->getPointeeType())) 1318 return TC_NotApplicable; 1319 1320 // B base of D 1321 QualType SrcClass(SrcMemPtr->getClass(), 0); 1322 QualType DestClass(DestMemPtr->getClass(), 0); 1323 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1324 /*DetectVirtual=*/true); 1325 if (!Self.IsDerivedFrom(SrcClass, DestClass, Paths)) { 1326 return TC_NotApplicable; 1327 } 1328 1329 // B is a base of D. But is it an allowed base? If not, it's a hard error. 1330 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) { 1331 Paths.clear(); 1332 Paths.setRecordingPaths(true); 1333 bool StillOkay = Self.IsDerivedFrom(SrcClass, DestClass, Paths); 1334 assert(StillOkay); 1335 (void)StillOkay; 1336 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths); 1337 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv) 1338 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange; 1339 msg = 0; 1340 return TC_Failed; 1341 } 1342 1343 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1344 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual) 1345 << SrcClass << DestClass << QualType(VBase, 0) << OpRange; 1346 msg = 0; 1347 return TC_Failed; 1348 } 1349 1350 if (!CStyle) { 1351 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1352 DestClass, SrcClass, 1353 Paths.front(), 1354 diag::err_upcast_to_inaccessible_base)) { 1355 case Sema::AR_accessible: 1356 case Sema::AR_delayed: 1357 case Sema::AR_dependent: 1358 // Optimistically assume that the delayed and dependent cases 1359 // will work out. 1360 break; 1361 1362 case Sema::AR_inaccessible: 1363 msg = 0; 1364 return TC_Failed; 1365 } 1366 } 1367 1368 if (WasOverloadedFunction) { 1369 // Resolve the address of the overloaded function again, this time 1370 // allowing complaints if something goes wrong. 1371 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 1372 DestType, 1373 true, 1374 FoundOverload); 1375 if (!Fn) { 1376 msg = 0; 1377 return TC_Failed; 1378 } 1379 1380 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn); 1381 if (!SrcExpr.isUsable()) { 1382 msg = 0; 1383 return TC_Failed; 1384 } 1385 } 1386 1387 Self.BuildBasePathArray(Paths, BasePath); 1388 Kind = CK_DerivedToBaseMemberPointer; 1389 return TC_Success; 1390} 1391 1392/// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2 1393/// is valid: 1394/// 1395/// An expression e can be explicitly converted to a type T using a 1396/// @c static_cast if the declaration "T t(e);" is well-formed [...]. 1397TryCastResult 1398TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType, 1399 Sema::CheckedConversionKind CCK, 1400 const SourceRange &OpRange, unsigned &msg, 1401 CastKind &Kind, bool ListInitialization) { 1402 if (DestType->isRecordType()) { 1403 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 1404 diag::err_bad_dynamic_cast_incomplete) || 1405 Self.RequireNonAbstractType(OpRange.getBegin(), DestType, 1406 diag::err_allocation_of_abstract_type)) { 1407 msg = 0; 1408 return TC_Failed; 1409 } 1410 } 1411 1412 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType); 1413 InitializationKind InitKind 1414 = (CCK == Sema::CCK_CStyleCast) 1415 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange, 1416 ListInitialization) 1417 : (CCK == Sema::CCK_FunctionalCast) 1418 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization) 1419 : InitializationKind::CreateCast(OpRange); 1420 Expr *SrcExprRaw = SrcExpr.get(); 1421 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw); 1422 1423 // At this point of CheckStaticCast, if the destination is a reference, 1424 // or the expression is an overload expression this has to work. 1425 // There is no other way that works. 1426 // On the other hand, if we're checking a C-style cast, we've still got 1427 // the reinterpret_cast way. 1428 bool CStyle 1429 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 1430 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType())) 1431 return TC_NotApplicable; 1432 1433 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw); 1434 if (Result.isInvalid()) { 1435 msg = 0; 1436 return TC_Failed; 1437 } 1438 1439 if (InitSeq.isConstructorInitialization()) 1440 Kind = CK_ConstructorConversion; 1441 else 1442 Kind = CK_NoOp; 1443 1444 SrcExpr = Result; 1445 return TC_Success; 1446} 1447 1448/// TryConstCast - See if a const_cast from source to destination is allowed, 1449/// and perform it if it is. 1450static TryCastResult TryConstCast(Sema &Self, Expr *SrcExpr, QualType DestType, 1451 bool CStyle, unsigned &msg) { 1452 DestType = Self.Context.getCanonicalType(DestType); 1453 QualType SrcType = SrcExpr->getType(); 1454 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) { 1455 if (DestTypeTmp->isLValueReferenceType() && !SrcExpr->isLValue()) { 1456 // Cannot const_cast non-lvalue to lvalue reference type. But if this 1457 // is C-style, static_cast might find a way, so we simply suggest a 1458 // message and tell the parent to keep searching. 1459 msg = diag::err_bad_cxx_cast_rvalue; 1460 return TC_NotApplicable; 1461 } 1462 1463 // C++ 5.2.11p4: An lvalue of type T1 can be [cast] to an lvalue of type T2 1464 // [...] if a pointer to T1 can be [cast] to the type pointer to T2. 1465 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1466 SrcType = Self.Context.getPointerType(SrcType); 1467 } 1468 1469 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...] 1470 // the rules for const_cast are the same as those used for pointers. 1471 1472 if (!DestType->isPointerType() && 1473 !DestType->isMemberPointerType() && 1474 !DestType->isObjCObjectPointerType()) { 1475 // Cannot cast to non-pointer, non-reference type. Note that, if DestType 1476 // was a reference type, we converted it to a pointer above. 1477 // The status of rvalue references isn't entirely clear, but it looks like 1478 // conversion to them is simply invalid. 1479 // C++ 5.2.11p3: For two pointer types [...] 1480 if (!CStyle) 1481 msg = diag::err_bad_const_cast_dest; 1482 return TC_NotApplicable; 1483 } 1484 if (DestType->isFunctionPointerType() || 1485 DestType->isMemberFunctionPointerType()) { 1486 // Cannot cast direct function pointers. 1487 // C++ 5.2.11p2: [...] where T is any object type or the void type [...] 1488 // T is the ultimate pointee of source and target type. 1489 if (!CStyle) 1490 msg = diag::err_bad_const_cast_dest; 1491 return TC_NotApplicable; 1492 } 1493 SrcType = Self.Context.getCanonicalType(SrcType); 1494 1495 // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are 1496 // completely equal. 1497 // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers 1498 // in multi-level pointers may change, but the level count must be the same, 1499 // as must be the final pointee type. 1500 while (SrcType != DestType && 1501 Self.Context.UnwrapSimilarPointerTypes(SrcType, DestType)) { 1502 Qualifiers SrcQuals, DestQuals; 1503 SrcType = Self.Context.getUnqualifiedArrayType(SrcType, SrcQuals); 1504 DestType = Self.Context.getUnqualifiedArrayType(DestType, DestQuals); 1505 1506 // const_cast is permitted to strip cvr-qualifiers, only. Make sure that 1507 // the other qualifiers (e.g., address spaces) are identical. 1508 SrcQuals.removeCVRQualifiers(); 1509 DestQuals.removeCVRQualifiers(); 1510 if (SrcQuals != DestQuals) 1511 return TC_NotApplicable; 1512 } 1513 1514 // Since we're dealing in canonical types, the remainder must be the same. 1515 if (SrcType != DestType) 1516 return TC_NotApplicable; 1517 1518 return TC_Success; 1519} 1520 1521// Checks for undefined behavior in reinterpret_cast. 1522// The cases that is checked for is: 1523// *reinterpret_cast<T*>(&a) 1524// reinterpret_cast<T&>(a) 1525// where accessing 'a' as type 'T' will result in undefined behavior. 1526void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType, 1527 bool IsDereference, 1528 SourceRange Range) { 1529 unsigned DiagID = IsDereference ? 1530 diag::warn_pointer_indirection_from_incompatible_type : 1531 diag::warn_undefined_reinterpret_cast; 1532 1533 if (Diags.getDiagnosticLevel(DiagID, Range.getBegin()) == 1534 DiagnosticsEngine::Ignored) { 1535 return; 1536 } 1537 1538 QualType SrcTy, DestTy; 1539 if (IsDereference) { 1540 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) { 1541 return; 1542 } 1543 SrcTy = SrcType->getPointeeType(); 1544 DestTy = DestType->getPointeeType(); 1545 } else { 1546 if (!DestType->getAs<ReferenceType>()) { 1547 return; 1548 } 1549 SrcTy = SrcType; 1550 DestTy = DestType->getPointeeType(); 1551 } 1552 1553 // Cast is compatible if the types are the same. 1554 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) { 1555 return; 1556 } 1557 // or one of the types is a char or void type 1558 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() || 1559 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) { 1560 return; 1561 } 1562 // or one of the types is a tag type. 1563 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) { 1564 return; 1565 } 1566 1567 // FIXME: Scoped enums? 1568 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) || 1569 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) { 1570 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) { 1571 return; 1572 } 1573 } 1574 1575 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range; 1576} 1577 1578static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr, 1579 QualType DestType) { 1580 QualType SrcType = SrcExpr.get()->getType(); 1581 if (Self.Context.hasSameType(SrcType, DestType)) 1582 return; 1583 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>()) 1584 if (SrcPtrTy->isObjCSelType()) { 1585 QualType DT = DestType; 1586 if (isa<PointerType>(DestType)) 1587 DT = DestType->getPointeeType(); 1588 if (!DT.getUnqualifiedType()->isVoidType()) 1589 Self.Diag(SrcExpr.get()->getExprLoc(), 1590 diag::warn_cast_pointer_from_sel) 1591 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 1592 } 1593} 1594 1595static void checkIntToPointerCast(bool CStyle, SourceLocation Loc, 1596 const Expr *SrcExpr, QualType DestType, 1597 Sema &Self) { 1598 QualType SrcType = SrcExpr->getType(); 1599 1600 // Not warning on reinterpret_cast, boolean, constant expressions, etc 1601 // are not explicit design choices, but consistent with GCC's behavior. 1602 // Feel free to modify them if you've reason/evidence for an alternative. 1603 if (CStyle && SrcType->isIntegralType(Self.Context) 1604 && !SrcType->isBooleanType() 1605 && !SrcType->isEnumeralType() 1606 && !SrcExpr->isIntegerConstantExpr(Self.Context) 1607 && Self.Context.getTypeSize(DestType) > Self.Context.getTypeSize(SrcType)) 1608 Self.Diag(Loc, diag::warn_int_to_pointer_cast) << SrcType << DestType; 1609} 1610 1611static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 1612 QualType DestType, bool CStyle, 1613 const SourceRange &OpRange, 1614 unsigned &msg, 1615 CastKind &Kind) { 1616 bool IsLValueCast = false; 1617 1618 DestType = Self.Context.getCanonicalType(DestType); 1619 QualType SrcType = SrcExpr.get()->getType(); 1620 1621 // Is the source an overloaded name? (i.e. &foo) 1622 // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5) ... 1623 if (SrcType == Self.Context.OverloadTy) { 1624 // ... unless foo<int> resolves to an lvalue unambiguously. 1625 // TODO: what if this fails because of DiagnoseUseOfDecl or something 1626 // like it? 1627 ExprResult SingleFunctionExpr = SrcExpr; 1628 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization( 1629 SingleFunctionExpr, 1630 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr 1631 ) && SingleFunctionExpr.isUsable()) { 1632 SrcExpr = SingleFunctionExpr; 1633 SrcType = SrcExpr.get()->getType(); 1634 } else { 1635 return TC_NotApplicable; 1636 } 1637 } 1638 1639 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) { 1640 if (!SrcExpr.get()->isGLValue()) { 1641 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the 1642 // similar comment in const_cast. 1643 msg = diag::err_bad_cxx_cast_rvalue; 1644 return TC_NotApplicable; 1645 } 1646 1647 if (!CStyle) { 1648 Self.CheckCompatibleReinterpretCast(SrcType, DestType, 1649 /*isDereference=*/false, OpRange); 1650 } 1651 1652 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the 1653 // same effect as the conversion *reinterpret_cast<T*>(&x) with the 1654 // built-in & and * operators. 1655 1656 const char *inappropriate = 0; 1657 switch (SrcExpr.get()->getObjectKind()) { 1658 case OK_Ordinary: 1659 break; 1660 case OK_BitField: inappropriate = "bit-field"; break; 1661 case OK_VectorComponent: inappropriate = "vector element"; break; 1662 case OK_ObjCProperty: inappropriate = "property expression"; break; 1663 case OK_ObjCSubscript: inappropriate = "container subscripting expression"; 1664 break; 1665 } 1666 if (inappropriate) { 1667 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference) 1668 << inappropriate << DestType 1669 << OpRange << SrcExpr.get()->getSourceRange(); 1670 msg = 0; SrcExpr = ExprError(); 1671 return TC_NotApplicable; 1672 } 1673 1674 // This code does this transformation for the checked types. 1675 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1676 SrcType = Self.Context.getPointerType(SrcType); 1677 1678 IsLValueCast = true; 1679 } 1680 1681 // Canonicalize source for comparison. 1682 SrcType = Self.Context.getCanonicalType(SrcType); 1683 1684 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(), 1685 *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1686 if (DestMemPtr && SrcMemPtr) { 1687 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1" 1688 // can be explicitly converted to an rvalue of type "pointer to member 1689 // of Y of type T2" if T1 and T2 are both function types or both object 1690 // types. 1691 if (DestMemPtr->getPointeeType()->isFunctionType() != 1692 SrcMemPtr->getPointeeType()->isFunctionType()) 1693 return TC_NotApplicable; 1694 1695 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away 1696 // constness. 1697 // A reinterpret_cast followed by a const_cast can, though, so in C-style, 1698 // we accept it. 1699 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1700 /*CheckObjCLifetime=*/CStyle)) { 1701 msg = diag::err_bad_cxx_cast_qualifiers_away; 1702 return TC_Failed; 1703 } 1704 1705 // Don't allow casting between member pointers of different sizes. 1706 if (Self.Context.getTypeSize(DestMemPtr) != 1707 Self.Context.getTypeSize(SrcMemPtr)) { 1708 msg = diag::err_bad_cxx_cast_member_pointer_size; 1709 return TC_Failed; 1710 } 1711 1712 // A valid member pointer cast. 1713 assert(!IsLValueCast); 1714 Kind = CK_ReinterpretMemberPointer; 1715 return TC_Success; 1716 } 1717 1718 // See below for the enumeral issue. 1719 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) { 1720 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral 1721 // type large enough to hold it. A value of std::nullptr_t can be 1722 // converted to an integral type; the conversion has the same meaning 1723 // and validity as a conversion of (void*)0 to the integral type. 1724 if (Self.Context.getTypeSize(SrcType) > 1725 Self.Context.getTypeSize(DestType)) { 1726 msg = diag::err_bad_reinterpret_cast_small_int; 1727 return TC_Failed; 1728 } 1729 Kind = CK_PointerToIntegral; 1730 return TC_Success; 1731 } 1732 1733 bool destIsVector = DestType->isVectorType(); 1734 bool srcIsVector = SrcType->isVectorType(); 1735 if (srcIsVector || destIsVector) { 1736 // FIXME: Should this also apply to floating point types? 1737 bool srcIsScalar = SrcType->isIntegralType(Self.Context); 1738 bool destIsScalar = DestType->isIntegralType(Self.Context); 1739 1740 // Check if this is a cast between a vector and something else. 1741 if (!(srcIsScalar && destIsVector) && !(srcIsVector && destIsScalar) && 1742 !(srcIsVector && destIsVector)) 1743 return TC_NotApplicable; 1744 1745 // If both types have the same size, we can successfully cast. 1746 if (Self.Context.getTypeSize(SrcType) 1747 == Self.Context.getTypeSize(DestType)) { 1748 Kind = CK_BitCast; 1749 return TC_Success; 1750 } 1751 1752 if (destIsScalar) 1753 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size; 1754 else if (srcIsScalar) 1755 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size; 1756 else 1757 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size; 1758 1759 return TC_Failed; 1760 } 1761 1762 if (SrcType == DestType) { 1763 // C++ 5.2.10p2 has a note that mentions that, subject to all other 1764 // restrictions, a cast to the same type is allowed so long as it does not 1765 // cast away constness. In C++98, the intent was not entirely clear here, 1766 // since all other paragraphs explicitly forbid casts to the same type. 1767 // C++11 clarifies this case with p2. 1768 // 1769 // The only allowed types are: integral, enumeration, pointer, or 1770 // pointer-to-member types. We also won't restrict Obj-C pointers either. 1771 Kind = CK_NoOp; 1772 TryCastResult Result = TC_NotApplicable; 1773 if (SrcType->isIntegralOrEnumerationType() || 1774 SrcType->isAnyPointerType() || 1775 SrcType->isMemberPointerType() || 1776 SrcType->isBlockPointerType()) { 1777 Result = TC_Success; 1778 } 1779 return Result; 1780 } 1781 1782 bool destIsPtr = DestType->isAnyPointerType() || 1783 DestType->isBlockPointerType(); 1784 bool srcIsPtr = SrcType->isAnyPointerType() || 1785 SrcType->isBlockPointerType(); 1786 if (!destIsPtr && !srcIsPtr) { 1787 // Except for std::nullptr_t->integer and lvalue->reference, which are 1788 // handled above, at least one of the two arguments must be a pointer. 1789 return TC_NotApplicable; 1790 } 1791 1792 if (DestType->isIntegralType(Self.Context)) { 1793 assert(srcIsPtr && "One type must be a pointer"); 1794 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral 1795 // type large enough to hold it; except in Microsoft mode, where the 1796 // integral type size doesn't matter. 1797 if ((Self.Context.getTypeSize(SrcType) > 1798 Self.Context.getTypeSize(DestType)) && 1799 !Self.getLangOpts().MicrosoftExt) { 1800 msg = diag::err_bad_reinterpret_cast_small_int; 1801 return TC_Failed; 1802 } 1803 Kind = CK_PointerToIntegral; 1804 return TC_Success; 1805 } 1806 1807 if (SrcType->isIntegralOrEnumerationType()) { 1808 assert(destIsPtr && "One type must be a pointer"); 1809 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType, 1810 Self); 1811 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly 1812 // converted to a pointer. 1813 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not 1814 // necessarily converted to a null pointer value.] 1815 Kind = CK_IntegralToPointer; 1816 return TC_Success; 1817 } 1818 1819 if (!destIsPtr || !srcIsPtr) { 1820 // With the valid non-pointer conversions out of the way, we can be even 1821 // more stringent. 1822 return TC_NotApplicable; 1823 } 1824 1825 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness. 1826 // The C-style cast operator can. 1827 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1828 /*CheckObjCLifetime=*/CStyle)) { 1829 msg = diag::err_bad_cxx_cast_qualifiers_away; 1830 return TC_Failed; 1831 } 1832 1833 // Cannot convert between block pointers and Objective-C object pointers. 1834 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) || 1835 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType())) 1836 return TC_NotApplicable; 1837 1838 if (IsLValueCast) { 1839 Kind = CK_LValueBitCast; 1840 } else if (DestType->isObjCObjectPointerType()) { 1841 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr); 1842 } else if (DestType->isBlockPointerType()) { 1843 if (!SrcType->isBlockPointerType()) { 1844 Kind = CK_AnyPointerToBlockPointerCast; 1845 } else { 1846 Kind = CK_BitCast; 1847 } 1848 } else { 1849 Kind = CK_BitCast; 1850 } 1851 1852 // Any pointer can be cast to an Objective-C pointer type with a C-style 1853 // cast. 1854 if (CStyle && DestType->isObjCObjectPointerType()) { 1855 return TC_Success; 1856 } 1857 if (CStyle) 1858 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 1859 1860 // Not casting away constness, so the only remaining check is for compatible 1861 // pointer categories. 1862 1863 if (SrcType->isFunctionPointerType()) { 1864 if (DestType->isFunctionPointerType()) { 1865 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to 1866 // a pointer to a function of a different type. 1867 return TC_Success; 1868 } 1869 1870 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to 1871 // an object type or vice versa is conditionally-supported. 1872 // Compilers support it in C++03 too, though, because it's necessary for 1873 // casting the return value of dlsym() and GetProcAddress(). 1874 // FIXME: Conditionally-supported behavior should be configurable in the 1875 // TargetInfo or similar. 1876 Self.Diag(OpRange.getBegin(), 1877 Self.getLangOpts().CPlusPlus11 ? 1878 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1879 << OpRange; 1880 return TC_Success; 1881 } 1882 1883 if (DestType->isFunctionPointerType()) { 1884 // See above. 1885 Self.Diag(OpRange.getBegin(), 1886 Self.getLangOpts().CPlusPlus11 ? 1887 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1888 << OpRange; 1889 return TC_Success; 1890 } 1891 1892 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to 1893 // a pointer to an object of different type. 1894 // Void pointers are not specified, but supported by every compiler out there. 1895 // So we finish by allowing everything that remains - it's got to be two 1896 // object pointers. 1897 return TC_Success; 1898} 1899 1900void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle, 1901 bool ListInitialization) { 1902 // Handle placeholders. 1903 if (isPlaceholder()) { 1904 // C-style casts can resolve __unknown_any types. 1905 if (claimPlaceholder(BuiltinType::UnknownAny)) { 1906 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 1907 SrcExpr.get(), Kind, 1908 ValueKind, BasePath); 1909 return; 1910 } 1911 1912 checkNonOverloadPlaceholders(); 1913 if (SrcExpr.isInvalid()) 1914 return; 1915 } 1916 1917 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 1918 // This test is outside everything else because it's the only case where 1919 // a non-lvalue-reference target type does not lead to decay. 1920 if (DestType->isVoidType()) { 1921 Kind = CK_ToVoid; 1922 1923 if (claimPlaceholder(BuiltinType::Overload)) { 1924 Self.ResolveAndFixSingleFunctionTemplateSpecialization( 1925 SrcExpr, /* Decay Function to ptr */ false, 1926 /* Complain */ true, DestRange, DestType, 1927 diag::err_bad_cstyle_cast_overload); 1928 if (SrcExpr.isInvalid()) 1929 return; 1930 } 1931 1932 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 1933 if (SrcExpr.isInvalid()) 1934 return; 1935 1936 return; 1937 } 1938 1939 // If the type is dependent, we won't do any other semantic analysis now. 1940 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent()) { 1941 assert(Kind == CK_Dependent); 1942 return; 1943 } 1944 1945 if (ValueKind == VK_RValue && !DestType->isRecordType() && 1946 !isPlaceholder(BuiltinType::Overload)) { 1947 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 1948 if (SrcExpr.isInvalid()) 1949 return; 1950 } 1951 1952 // AltiVec vector initialization with a single literal. 1953 if (const VectorType *vecTy = DestType->getAs<VectorType>()) 1954 if (vecTy->getVectorKind() == VectorType::AltiVecVector 1955 && (SrcExpr.get()->getType()->isIntegerType() 1956 || SrcExpr.get()->getType()->isFloatingType())) { 1957 Kind = CK_VectorSplat; 1958 return; 1959 } 1960 1961 // C++ [expr.cast]p5: The conversions performed by 1962 // - a const_cast, 1963 // - a static_cast, 1964 // - a static_cast followed by a const_cast, 1965 // - a reinterpret_cast, or 1966 // - a reinterpret_cast followed by a const_cast, 1967 // can be performed using the cast notation of explicit type conversion. 1968 // [...] If a conversion can be interpreted in more than one of the ways 1969 // listed above, the interpretation that appears first in the list is used, 1970 // even if a cast resulting from that interpretation is ill-formed. 1971 // In plain language, this means trying a const_cast ... 1972 unsigned msg = diag::err_bad_cxx_cast_generic; 1973 TryCastResult tcr = TryConstCast(Self, SrcExpr.get(), DestType, 1974 /*CStyle*/true, msg); 1975 if (tcr == TC_Success) 1976 Kind = CK_NoOp; 1977 1978 Sema::CheckedConversionKind CCK 1979 = FunctionalStyle? Sema::CCK_FunctionalCast 1980 : Sema::CCK_CStyleCast; 1981 if (tcr == TC_NotApplicable) { 1982 // ... or if that is not possible, a static_cast, ignoring const, ... 1983 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, 1984 msg, Kind, BasePath, ListInitialization); 1985 if (SrcExpr.isInvalid()) 1986 return; 1987 1988 if (tcr == TC_NotApplicable) { 1989 // ... and finally a reinterpret_cast, ignoring const. 1990 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true, 1991 OpRange, msg, Kind); 1992 if (SrcExpr.isInvalid()) 1993 return; 1994 } 1995 } 1996 1997 if (Self.getLangOpts().ObjCAutoRefCount && tcr == TC_Success) 1998 checkObjCARCConversion(CCK); 1999 2000 if (tcr != TC_Success && msg != 0) { 2001 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 2002 DeclAccessPair Found; 2003 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 2004 DestType, 2005 /*Complain*/ true, 2006 Found); 2007 2008 assert(!Fn && "cast failed but able to resolve overload expression!!"); 2009 (void)Fn; 2010 2011 } else { 2012 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle), 2013 OpRange, SrcExpr.get(), DestType, ListInitialization); 2014 } 2015 } else if (Kind == CK_BitCast) { 2016 checkCastAlign(); 2017 } 2018 2019 // Clear out SrcExpr if there was a fatal error. 2020 if (tcr != TC_Success) 2021 SrcExpr = ExprError(); 2022} 2023 2024/// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a 2025/// non-matching type. Such as enum function call to int, int call to 2026/// pointer; etc. Cast to 'void' is an exception. 2027static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr, 2028 QualType DestType) { 2029 if (Self.Diags.getDiagnosticLevel(diag::warn_bad_function_cast, 2030 SrcExpr.get()->getExprLoc()) 2031 == DiagnosticsEngine::Ignored) 2032 return; 2033 2034 if (!isa<CallExpr>(SrcExpr.get())) 2035 return; 2036 2037 QualType SrcType = SrcExpr.get()->getType(); 2038 if (DestType.getUnqualifiedType()->isVoidType()) 2039 return; 2040 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType()) 2041 && (DestType->isAnyPointerType() || DestType->isBlockPointerType())) 2042 return; 2043 if (SrcType->isIntegerType() && DestType->isIntegerType() && 2044 (SrcType->isBooleanType() == DestType->isBooleanType()) && 2045 (SrcType->isEnumeralType() == DestType->isEnumeralType())) 2046 return; 2047 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType()) 2048 return; 2049 if (SrcType->isEnumeralType() && DestType->isEnumeralType()) 2050 return; 2051 if (SrcType->isComplexType() && DestType->isComplexType()) 2052 return; 2053 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType()) 2054 return; 2055 2056 Self.Diag(SrcExpr.get()->getExprLoc(), 2057 diag::warn_bad_function_cast) 2058 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2059} 2060 2061/// Check the semantics of a C-style cast operation, in C. 2062void CastOperation::CheckCStyleCast() { 2063 assert(!Self.getLangOpts().CPlusPlus); 2064 2065 // C-style casts can resolve __unknown_any types. 2066 if (claimPlaceholder(BuiltinType::UnknownAny)) { 2067 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 2068 SrcExpr.get(), Kind, 2069 ValueKind, BasePath); 2070 return; 2071 } 2072 2073 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression 2074 // type needs to be scalar. 2075 if (DestType->isVoidType()) { 2076 // We don't necessarily do lvalue-to-rvalue conversions on this. 2077 SrcExpr = Self.IgnoredValueConversions(SrcExpr.take()); 2078 if (SrcExpr.isInvalid()) 2079 return; 2080 2081 // Cast to void allows any expr type. 2082 Kind = CK_ToVoid; 2083 return; 2084 } 2085 2086 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.take()); 2087 if (SrcExpr.isInvalid()) 2088 return; 2089 QualType SrcType = SrcExpr.get()->getType(); 2090 2091 assert(!SrcType->isPlaceholderType()); 2092 2093 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 2094 diag::err_typecheck_cast_to_incomplete)) { 2095 SrcExpr = ExprError(); 2096 return; 2097 } 2098 2099 if (!DestType->isScalarType() && !DestType->isVectorType()) { 2100 const RecordType *DestRecordTy = DestType->getAs<RecordType>(); 2101 2102 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){ 2103 // GCC struct/union extension: allow cast to self. 2104 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar) 2105 << DestType << SrcExpr.get()->getSourceRange(); 2106 Kind = CK_NoOp; 2107 return; 2108 } 2109 2110 // GCC's cast to union extension. 2111 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) { 2112 RecordDecl *RD = DestRecordTy->getDecl(); 2113 RecordDecl::field_iterator Field, FieldEnd; 2114 for (Field = RD->field_begin(), FieldEnd = RD->field_end(); 2115 Field != FieldEnd; ++Field) { 2116 if (Self.Context.hasSameUnqualifiedType(Field->getType(), SrcType) && 2117 !Field->isUnnamedBitfield()) { 2118 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union) 2119 << SrcExpr.get()->getSourceRange(); 2120 break; 2121 } 2122 } 2123 if (Field == FieldEnd) { 2124 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type) 2125 << SrcType << SrcExpr.get()->getSourceRange(); 2126 SrcExpr = ExprError(); 2127 return; 2128 } 2129 Kind = CK_ToUnion; 2130 return; 2131 } 2132 2133 // Reject any other conversions to non-scalar types. 2134 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar) 2135 << DestType << SrcExpr.get()->getSourceRange(); 2136 SrcExpr = ExprError(); 2137 return; 2138 } 2139 2140 // The type we're casting to is known to be a scalar or vector. 2141 2142 // Require the operand to be a scalar or vector. 2143 if (!SrcType->isScalarType() && !SrcType->isVectorType()) { 2144 Self.Diag(SrcExpr.get()->getExprLoc(), 2145 diag::err_typecheck_expect_scalar_operand) 2146 << SrcType << SrcExpr.get()->getSourceRange(); 2147 SrcExpr = ExprError(); 2148 return; 2149 } 2150 2151 if (DestType->isExtVectorType()) { 2152 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.take(), Kind); 2153 return; 2154 } 2155 2156 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) { 2157 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector && 2158 (SrcType->isIntegerType() || SrcType->isFloatingType())) { 2159 Kind = CK_VectorSplat; 2160 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) { 2161 SrcExpr = ExprError(); 2162 } 2163 return; 2164 } 2165 2166 if (SrcType->isVectorType()) { 2167 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind)) 2168 SrcExpr = ExprError(); 2169 return; 2170 } 2171 2172 // The source and target types are both scalars, i.e. 2173 // - arithmetic types (fundamental, enum, and complex) 2174 // - all kinds of pointers 2175 // Note that member pointers were filtered out with C++, above. 2176 2177 if (isa<ObjCSelectorExpr>(SrcExpr.get())) { 2178 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr); 2179 SrcExpr = ExprError(); 2180 return; 2181 } 2182 2183 // If either type is a pointer, the other type has to be either an 2184 // integer or a pointer. 2185 if (!DestType->isArithmeticType()) { 2186 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) { 2187 Self.Diag(SrcExpr.get()->getExprLoc(), 2188 diag::err_cast_pointer_from_non_pointer_int) 2189 << SrcType << SrcExpr.get()->getSourceRange(); 2190 SrcExpr = ExprError(); 2191 return; 2192 } 2193 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(), 2194 DestType, Self); 2195 } else if (!SrcType->isArithmeticType()) { 2196 if (!DestType->isIntegralType(Self.Context) && 2197 DestType->isArithmeticType()) { 2198 Self.Diag(SrcExpr.get()->getLocStart(), 2199 diag::err_cast_pointer_to_non_pointer_int) 2200 << DestType << SrcExpr.get()->getSourceRange(); 2201 SrcExpr = ExprError(); 2202 return; 2203 } 2204 } 2205 2206 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().cl_khr_fp16) { 2207 if (DestType->isHalfType()) { 2208 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half) 2209 << DestType << SrcExpr.get()->getSourceRange(); 2210 SrcExpr = ExprError(); 2211 return; 2212 } 2213 } 2214 2215 // ARC imposes extra restrictions on casts. 2216 if (Self.getLangOpts().ObjCAutoRefCount) { 2217 checkObjCARCConversion(Sema::CCK_CStyleCast); 2218 if (SrcExpr.isInvalid()) 2219 return; 2220 2221 if (const PointerType *CastPtr = DestType->getAs<PointerType>()) { 2222 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) { 2223 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers(); 2224 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers(); 2225 if (CastPtr->getPointeeType()->isObjCLifetimeType() && 2226 ExprPtr->getPointeeType()->isObjCLifetimeType() && 2227 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) { 2228 Self.Diag(SrcExpr.get()->getLocStart(), 2229 diag::err_typecheck_incompatible_ownership) 2230 << SrcType << DestType << Sema::AA_Casting 2231 << SrcExpr.get()->getSourceRange(); 2232 return; 2233 } 2234 } 2235 } 2236 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) { 2237 Self.Diag(SrcExpr.get()->getLocStart(), 2238 diag::err_arc_convesion_of_weak_unavailable) 2239 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2240 SrcExpr = ExprError(); 2241 return; 2242 } 2243 } 2244 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 2245 DiagnoseBadFunctionCast(Self, SrcExpr, DestType); 2246 Kind = Self.PrepareScalarCast(SrcExpr, DestType); 2247 if (SrcExpr.isInvalid()) 2248 return; 2249 2250 if (Kind == CK_BitCast) 2251 checkCastAlign(); 2252} 2253 2254ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc, 2255 TypeSourceInfo *CastTypeInfo, 2256 SourceLocation RPLoc, 2257 Expr *CastExpr) { 2258 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2259 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2260 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd()); 2261 2262 if (getLangOpts().CPlusPlus) { 2263 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false, 2264 isa<InitListExpr>(CastExpr)); 2265 } else { 2266 Op.CheckCStyleCast(); 2267 } 2268 2269 if (Op.SrcExpr.isInvalid()) 2270 return ExprError(); 2271 2272 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType, 2273 Op.ValueKind, Op.Kind, Op.SrcExpr.take(), 2274 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc)); 2275} 2276 2277ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo, 2278 SourceLocation LPLoc, 2279 Expr *CastExpr, 2280 SourceLocation RPLoc) { 2281 assert(LPLoc.isValid() && "List-initialization shouldn't get here."); 2282 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2283 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2284 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd()); 2285 2286 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false); 2287 if (Op.SrcExpr.isInvalid()) 2288 return ExprError(); 2289 2290 if (CXXConstructExpr *ConstructExpr = dyn_cast<CXXConstructExpr>(Op.SrcExpr.get())) 2291 ConstructExpr->setParenRange(SourceRange(LPLoc, RPLoc)); 2292 2293 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType, 2294 Op.ValueKind, CastTypeInfo, Op.DestRange.getBegin(), 2295 Op.Kind, Op.SrcExpr.take(), &Op.BasePath, RPLoc)); 2296} 2297