SemaExprCXX.cpp revision e127ae3174322af06f6934a81edadf5931cad1b2
1//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===// 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 C++ expressions. 11// 12//===----------------------------------------------------------------------===// 13 14#include "SemaInherit.h" 15#include "Sema.h" 16#include "clang/AST/ExprCXX.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/Parse/DeclSpec.h" 19#include "clang/Lex/Preprocessor.h" 20#include "clang/Basic/TargetInfo.h" 21#include "llvm/ADT/STLExtras.h" 22using namespace clang; 23 24/// ActOnCXXConversionFunctionExpr - Parse a C++ conversion function 25/// name (e.g., operator void const *) as an expression. This is 26/// very similar to ActOnIdentifierExpr, except that instead of 27/// providing an identifier the parser provides the type of the 28/// conversion function. 29Sema::OwningExprResult 30Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc, 31 TypeTy *Ty, bool HasTrailingLParen, 32 const CXXScopeSpec &SS, 33 bool isAddressOfOperand) { 34 QualType ConvType = QualType::getFromOpaquePtr(Ty); 35 QualType ConvTypeCanon = Context.getCanonicalType(ConvType); 36 DeclarationName ConvName 37 = Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon); 38 return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen, 39 &SS, isAddressOfOperand); 40} 41 42/// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator 43/// name (e.g., @c operator+ ) as an expression. This is very 44/// similar to ActOnIdentifierExpr, except that instead of providing 45/// an identifier the parser provides the kind of overloaded 46/// operator that was parsed. 47Sema::OwningExprResult 48Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc, 49 OverloadedOperatorKind Op, 50 bool HasTrailingLParen, 51 const CXXScopeSpec &SS, 52 bool isAddressOfOperand) { 53 DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op); 54 return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS, 55 isAddressOfOperand); 56} 57 58/// ActOnCXXTypeidOfType - Parse typeid( type-id ). 59Action::OwningExprResult 60Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc, 61 bool isType, void *TyOrExpr, SourceLocation RParenLoc) { 62 NamespaceDecl *StdNs = GetStdNamespace(); 63 if (!StdNs) 64 return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid)); 65 66 IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info"); 67 Decl *TypeInfoDecl = LookupQualifiedName(StdNs, TypeInfoII, LookupTagName); 68 RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null<RecordDecl>(TypeInfoDecl); 69 if (!TypeInfoRecordDecl) 70 return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid)); 71 72 QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl); 73 74 return Owned(new (Context) CXXTypeidExpr(isType, TyOrExpr, 75 TypeInfoType.withConst(), 76 SourceRange(OpLoc, RParenLoc))); 77} 78 79/// ActOnCXXBoolLiteral - Parse {true,false} literals. 80Action::OwningExprResult 81Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) { 82 assert((Kind == tok::kw_true || Kind == tok::kw_false) && 83 "Unknown C++ Boolean value!"); 84 return Owned(new (Context) CXXBoolLiteralExpr(Kind == tok::kw_true, 85 Context.BoolTy, OpLoc)); 86} 87 88/// ActOnCXXNullPtrLiteral - Parse 'nullptr'. 89Action::OwningExprResult 90Sema::ActOnCXXNullPtrLiteral(SourceLocation Loc) { 91 return Owned(new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc)); 92} 93 94/// ActOnCXXThrow - Parse throw expressions. 95Action::OwningExprResult 96Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprArg E) { 97 Expr *Ex = E.takeAs<Expr>(); 98 if (Ex && !Ex->isTypeDependent() && CheckCXXThrowOperand(OpLoc, Ex)) 99 return ExprError(); 100 return Owned(new (Context) CXXThrowExpr(Ex, Context.VoidTy, OpLoc)); 101} 102 103/// CheckCXXThrowOperand - Validate the operand of a throw. 104bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) { 105 // C++ [except.throw]p3: 106 // [...] adjusting the type from "array of T" or "function returning T" 107 // to "pointer to T" or "pointer to function returning T", [...] 108 DefaultFunctionArrayConversion(E); 109 110 // If the type of the exception would be an incomplete type or a pointer 111 // to an incomplete type other than (cv) void the program is ill-formed. 112 QualType Ty = E->getType(); 113 int isPointer = 0; 114 if (const PointerType* Ptr = Ty->getAsPointerType()) { 115 Ty = Ptr->getPointeeType(); 116 isPointer = 1; 117 } 118 if (!isPointer || !Ty->isVoidType()) { 119 if (RequireCompleteType(ThrowLoc, Ty, 120 isPointer ? diag::err_throw_incomplete_ptr 121 : diag::err_throw_incomplete, 122 E->getSourceRange(), SourceRange(), QualType())) 123 return true; 124 } 125 126 // FIXME: Construct a temporary here. 127 return false; 128} 129 130Action::OwningExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) { 131 /// C++ 9.3.2: In the body of a non-static member function, the keyword this 132 /// is a non-lvalue expression whose value is the address of the object for 133 /// which the function is called. 134 135 if (!isa<FunctionDecl>(CurContext)) 136 return ExprError(Diag(ThisLoc, diag::err_invalid_this_use)); 137 138 if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) 139 if (MD->isInstance()) 140 return Owned(new (Context) CXXThisExpr(ThisLoc, 141 MD->getThisType(Context))); 142 143 return ExprError(Diag(ThisLoc, diag::err_invalid_this_use)); 144} 145 146/// ActOnCXXTypeConstructExpr - Parse construction of a specified type. 147/// Can be interpreted either as function-style casting ("int(x)") 148/// or class type construction ("ClassType(x,y,z)") 149/// or creation of a value-initialized type ("int()"). 150Action::OwningExprResult 151Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep, 152 SourceLocation LParenLoc, 153 MultiExprArg exprs, 154 SourceLocation *CommaLocs, 155 SourceLocation RParenLoc) { 156 assert(TypeRep && "Missing type!"); 157 QualType Ty = QualType::getFromOpaquePtr(TypeRep); 158 unsigned NumExprs = exprs.size(); 159 Expr **Exprs = (Expr**)exprs.get(); 160 SourceLocation TyBeginLoc = TypeRange.getBegin(); 161 SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc); 162 163 if (Ty->isDependentType() || 164 CallExpr::hasAnyTypeDependentArguments(Exprs, NumExprs)) { 165 exprs.release(); 166 167 // FIXME: Is this correct? 168 CXXTempVarDecl *Temp = CXXTempVarDecl::Create(Context, CurContext, Ty); 169 return Owned(new (Context) CXXTemporaryObjectExpr(Context, Temp, 0, Ty, 170 TyBeginLoc, 171 Exprs, NumExprs, 172 RParenLoc)); 173 } 174 175 176 // C++ [expr.type.conv]p1: 177 // If the expression list is a single expression, the type conversion 178 // expression is equivalent (in definedness, and if defined in meaning) to the 179 // corresponding cast expression. 180 // 181 if (NumExprs == 1) { 182 if (CheckCastTypes(TypeRange, Ty, Exprs[0])) 183 return ExprError(); 184 exprs.release(); 185 return Owned(new (Context) CXXFunctionalCastExpr(Ty.getNonReferenceType(), 186 Ty, TyBeginLoc, Exprs[0], 187 RParenLoc)); 188 } 189 190 if (const RecordType *RT = Ty->getAsRecordType()) { 191 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); 192 193 if (NumExprs > 1 || Record->hasUserDeclaredConstructor()) { 194 CXXConstructorDecl *Constructor 195 = PerformInitializationByConstructor(Ty, Exprs, NumExprs, 196 TypeRange.getBegin(), 197 SourceRange(TypeRange.getBegin(), 198 RParenLoc), 199 DeclarationName(), 200 IK_Direct); 201 202 if (!Constructor) 203 return ExprError(); 204 205 CXXTempVarDecl *Temp = CXXTempVarDecl::Create(Context, CurContext, Ty); 206 207 exprs.release(); 208 return Owned(new (Context) CXXTemporaryObjectExpr(Context, Temp, 209 Constructor, Ty, 210 TyBeginLoc, Exprs, 211 NumExprs, RParenLoc)); 212 } 213 214 // Fall through to value-initialize an object of class type that 215 // doesn't have a user-declared default constructor. 216 } 217 218 // C++ [expr.type.conv]p1: 219 // If the expression list specifies more than a single value, the type shall 220 // be a class with a suitably declared constructor. 221 // 222 if (NumExprs > 1) 223 return ExprError(Diag(CommaLocs[0], 224 diag::err_builtin_func_cast_more_than_one_arg) 225 << FullRange); 226 227 assert(NumExprs == 0 && "Expected 0 expressions"); 228 229 // C++ [expr.type.conv]p2: 230 // The expression T(), where T is a simple-type-specifier for a non-array 231 // complete object type or the (possibly cv-qualified) void type, creates an 232 // rvalue of the specified type, which is value-initialized. 233 // 234 if (Ty->isArrayType()) 235 return ExprError(Diag(TyBeginLoc, 236 diag::err_value_init_for_array_type) << FullRange); 237 if (!Ty->isDependentType() && !Ty->isVoidType() && 238 RequireCompleteType(TyBeginLoc, Ty, 239 diag::err_invalid_incomplete_type_use, FullRange)) 240 return ExprError(); 241 242 if (RequireNonAbstractType(TyBeginLoc, Ty, 243 diag::err_allocation_of_abstract_type)) 244 return ExprError(); 245 246 exprs.release(); 247 return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc)); 248} 249 250 251/// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.: 252/// @code new (memory) int[size][4] @endcode 253/// or 254/// @code ::new Foo(23, "hello") @endcode 255/// For the interpretation of this heap of arguments, consult the base version. 256Action::OwningExprResult 257Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal, 258 SourceLocation PlacementLParen, MultiExprArg PlacementArgs, 259 SourceLocation PlacementRParen, bool ParenTypeId, 260 Declarator &D, SourceLocation ConstructorLParen, 261 MultiExprArg ConstructorArgs, 262 SourceLocation ConstructorRParen) 263{ 264 Expr *ArraySize = 0; 265 unsigned Skip = 0; 266 // If the specified type is an array, unwrap it and save the expression. 267 if (D.getNumTypeObjects() > 0 && 268 D.getTypeObject(0).Kind == DeclaratorChunk::Array) { 269 DeclaratorChunk &Chunk = D.getTypeObject(0); 270 if (Chunk.Arr.hasStatic) 271 return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new) 272 << D.getSourceRange()); 273 if (!Chunk.Arr.NumElts) 274 return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size) 275 << D.getSourceRange()); 276 ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts); 277 Skip = 1; 278 } 279 280 QualType AllocType = GetTypeForDeclarator(D, /*Scope=*/0, Skip); 281 if (D.isInvalidType()) 282 return ExprError(); 283 284 if (CheckAllocatedType(AllocType, D)) 285 return ExprError(); 286 287 QualType ResultType = AllocType->isDependentType() 288 ? Context.DependentTy 289 : Context.getPointerType(AllocType); 290 291 // That every array dimension except the first is constant was already 292 // checked by the type check above. 293 294 // C++ 5.3.4p6: "The expression in a direct-new-declarator shall have integral 295 // or enumeration type with a non-negative value." 296 if (ArraySize && !ArraySize->isTypeDependent()) { 297 QualType SizeType = ArraySize->getType(); 298 if (!SizeType->isIntegralType() && !SizeType->isEnumeralType()) 299 return ExprError(Diag(ArraySize->getSourceRange().getBegin(), 300 diag::err_array_size_not_integral) 301 << SizeType << ArraySize->getSourceRange()); 302 // Let's see if this is a constant < 0. If so, we reject it out of hand. 303 // We don't care about special rules, so we tell the machinery it's not 304 // evaluated - it gives us a result in more cases. 305 if (!ArraySize->isValueDependent()) { 306 llvm::APSInt Value; 307 if (ArraySize->isIntegerConstantExpr(Value, Context, 0, false)) { 308 if (Value < llvm::APSInt( 309 llvm::APInt::getNullValue(Value.getBitWidth()), false)) 310 return ExprError(Diag(ArraySize->getSourceRange().getBegin(), 311 diag::err_typecheck_negative_array_size) 312 << ArraySize->getSourceRange()); 313 } 314 } 315 } 316 317 FunctionDecl *OperatorNew = 0; 318 FunctionDecl *OperatorDelete = 0; 319 Expr **PlaceArgs = (Expr**)PlacementArgs.get(); 320 unsigned NumPlaceArgs = PlacementArgs.size(); 321 if (!AllocType->isDependentType() && 322 !Expr::hasAnyTypeDependentArguments(PlaceArgs, NumPlaceArgs) && 323 FindAllocationFunctions(StartLoc, 324 SourceRange(PlacementLParen, PlacementRParen), 325 UseGlobal, AllocType, ArraySize, PlaceArgs, 326 NumPlaceArgs, OperatorNew, OperatorDelete)) 327 return ExprError(); 328 329 bool Init = ConstructorLParen.isValid(); 330 // --- Choosing a constructor --- 331 // C++ 5.3.4p15 332 // 1) If T is a POD and there's no initializer (ConstructorLParen is invalid) 333 // the object is not initialized. If the object, or any part of it, is 334 // const-qualified, it's an error. 335 // 2) If T is a POD and there's an empty initializer, the object is value- 336 // initialized. 337 // 3) If T is a POD and there's one initializer argument, the object is copy- 338 // constructed. 339 // 4) If T is a POD and there's more initializer arguments, it's an error. 340 // 5) If T is not a POD, the initializer arguments are used as constructor 341 // arguments. 342 // 343 // Or by the C++0x formulation: 344 // 1) If there's no initializer, the object is default-initialized according 345 // to C++0x rules. 346 // 2) Otherwise, the object is direct-initialized. 347 CXXConstructorDecl *Constructor = 0; 348 Expr **ConsArgs = (Expr**)ConstructorArgs.get(); 349 const RecordType *RT; 350 unsigned NumConsArgs = ConstructorArgs.size(); 351 if (AllocType->isDependentType()) { 352 // Skip all the checks. 353 } 354 else if ((RT = AllocType->getAsRecordType()) && 355 !AllocType->isAggregateType()) { 356 Constructor = PerformInitializationByConstructor( 357 AllocType, ConsArgs, NumConsArgs, 358 D.getSourceRange().getBegin(), 359 SourceRange(D.getSourceRange().getBegin(), 360 ConstructorRParen), 361 RT->getDecl()->getDeclName(), 362 NumConsArgs != 0 ? IK_Direct : IK_Default); 363 if (!Constructor) 364 return ExprError(); 365 } else { 366 if (!Init) { 367 // FIXME: Check that no subpart is const. 368 if (AllocType.isConstQualified()) 369 return ExprError(Diag(StartLoc, diag::err_new_uninitialized_const) 370 << D.getSourceRange()); 371 } else if (NumConsArgs == 0) { 372 // Object is value-initialized. Do nothing. 373 } else if (NumConsArgs == 1) { 374 // Object is direct-initialized. 375 // FIXME: What DeclarationName do we pass in here? 376 if (CheckInitializerTypes(ConsArgs[0], AllocType, StartLoc, 377 DeclarationName() /*AllocType.getAsString()*/, 378 /*DirectInit=*/true)) 379 return ExprError(); 380 } else { 381 return ExprError(Diag(StartLoc, 382 diag::err_builtin_direct_init_more_than_one_arg) 383 << SourceRange(ConstructorLParen, ConstructorRParen)); 384 } 385 } 386 387 // FIXME: Also check that the destructor is accessible. (C++ 5.3.4p16) 388 389 PlacementArgs.release(); 390 ConstructorArgs.release(); 391 return Owned(new (Context) CXXNewExpr(UseGlobal, OperatorNew, PlaceArgs, 392 NumPlaceArgs, ParenTypeId, ArraySize, Constructor, Init, 393 ConsArgs, NumConsArgs, OperatorDelete, ResultType, 394 StartLoc, Init ? ConstructorRParen : SourceLocation())); 395} 396 397/// CheckAllocatedType - Checks that a type is suitable as the allocated type 398/// in a new-expression. 399/// dimension off and stores the size expression in ArraySize. 400bool Sema::CheckAllocatedType(QualType AllocType, const Declarator &D) 401{ 402 // C++ 5.3.4p1: "[The] type shall be a complete object type, but not an 403 // abstract class type or array thereof. 404 if (AllocType->isFunctionType()) 405 return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type) 406 << AllocType << 0 << D.getSourceRange(); 407 else if (AllocType->isReferenceType()) 408 return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type) 409 << AllocType << 1 << D.getSourceRange(); 410 else if (!AllocType->isDependentType() && 411 RequireCompleteType(D.getSourceRange().getBegin(), AllocType, 412 diag::err_new_incomplete_type, 413 D.getSourceRange())) 414 return true; 415 else if (RequireNonAbstractType(D.getSourceRange().getBegin(), AllocType, 416 diag::err_allocation_of_abstract_type)) 417 return true; 418 419 // Every dimension shall be of constant size. 420 unsigned i = 1; 421 while (const ArrayType *Array = Context.getAsArrayType(AllocType)) { 422 if (!Array->isConstantArrayType()) { 423 Diag(D.getTypeObject(i).Loc, diag::err_new_array_nonconst) 424 << static_cast<Expr*>(D.getTypeObject(i).Arr.NumElts)->getSourceRange(); 425 return true; 426 } 427 AllocType = Array->getElementType(); 428 ++i; 429 } 430 431 return false; 432} 433 434/// FindAllocationFunctions - Finds the overloads of operator new and delete 435/// that are appropriate for the allocation. 436bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range, 437 bool UseGlobal, QualType AllocType, 438 bool IsArray, Expr **PlaceArgs, 439 unsigned NumPlaceArgs, 440 FunctionDecl *&OperatorNew, 441 FunctionDecl *&OperatorDelete) 442{ 443 // --- Choosing an allocation function --- 444 // C++ 5.3.4p8 - 14 & 18 445 // 1) If UseGlobal is true, only look in the global scope. Else, also look 446 // in the scope of the allocated class. 447 // 2) If an array size is given, look for operator new[], else look for 448 // operator new. 449 // 3) The first argument is always size_t. Append the arguments from the 450 // placement form. 451 // FIXME: Also find the appropriate delete operator. 452 453 llvm::SmallVector<Expr*, 8> AllocArgs(1 + NumPlaceArgs); 454 // We don't care about the actual value of this argument. 455 // FIXME: Should the Sema create the expression and embed it in the syntax 456 // tree? Or should the consumer just recalculate the value? 457 AllocArgs[0] = new (Context) IntegerLiteral(llvm::APInt::getNullValue( 458 Context.Target.getPointerWidth(0)), 459 Context.getSizeType(), 460 SourceLocation()); 461 std::copy(PlaceArgs, PlaceArgs + NumPlaceArgs, AllocArgs.begin() + 1); 462 463 DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName( 464 IsArray ? OO_Array_New : OO_New); 465 if (AllocType->isRecordType() && !UseGlobal) { 466 CXXRecordDecl *Record 467 = cast<CXXRecordDecl>(AllocType->getAsRecordType()->getDecl()); 468 // FIXME: We fail to find inherited overloads. 469 if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0], 470 AllocArgs.size(), Record, /*AllowMissing=*/true, 471 OperatorNew)) 472 return true; 473 } 474 if (!OperatorNew) { 475 // Didn't find a member overload. Look for a global one. 476 DeclareGlobalNewDelete(); 477 DeclContext *TUDecl = Context.getTranslationUnitDecl(); 478 if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0], 479 AllocArgs.size(), TUDecl, /*AllowMissing=*/false, 480 OperatorNew)) 481 return true; 482 } 483 484 // FIXME: This is leaked on error. But so much is currently in Sema that it's 485 // easier to clean it in one go. 486 AllocArgs[0]->Destroy(Context); 487 return false; 488} 489 490/// FindAllocationOverload - Find an fitting overload for the allocation 491/// function in the specified scope. 492bool Sema::FindAllocationOverload(SourceLocation StartLoc, SourceRange Range, 493 DeclarationName Name, Expr** Args, 494 unsigned NumArgs, DeclContext *Ctx, 495 bool AllowMissing, FunctionDecl *&Operator) 496{ 497 DeclContext::lookup_iterator Alloc, AllocEnd; 498 llvm::tie(Alloc, AllocEnd) = Ctx->lookup(Context, Name); 499 if (Alloc == AllocEnd) { 500 if (AllowMissing) 501 return false; 502 return Diag(StartLoc, diag::err_ovl_no_viable_function_in_call) 503 << Name << Range; 504 } 505 506 OverloadCandidateSet Candidates; 507 for (; Alloc != AllocEnd; ++Alloc) { 508 // Even member operator new/delete are implicitly treated as 509 // static, so don't use AddMemberCandidate. 510 if (FunctionDecl *Fn = dyn_cast<FunctionDecl>(*Alloc)) 511 AddOverloadCandidate(Fn, Args, NumArgs, Candidates, 512 /*SuppressUserConversions=*/false); 513 } 514 515 // Do the resolution. 516 OverloadCandidateSet::iterator Best; 517 switch(BestViableFunction(Candidates, Best)) { 518 case OR_Success: { 519 // Got one! 520 FunctionDecl *FnDecl = Best->Function; 521 // The first argument is size_t, and the first parameter must be size_t, 522 // too. This is checked on declaration and can be assumed. (It can't be 523 // asserted on, though, since invalid decls are left in there.) 524 for (unsigned i = 1; i < NumArgs; ++i) { 525 // FIXME: Passing word to diagnostic. 526 if (PerformCopyInitialization(Args[i-1], 527 FnDecl->getParamDecl(i)->getType(), 528 "passing")) 529 return true; 530 } 531 Operator = FnDecl; 532 return false; 533 } 534 535 case OR_No_Viable_Function: 536 Diag(StartLoc, diag::err_ovl_no_viable_function_in_call) 537 << Name << Range; 538 PrintOverloadCandidates(Candidates, /*OnlyViable=*/false); 539 return true; 540 541 case OR_Ambiguous: 542 Diag(StartLoc, diag::err_ovl_ambiguous_call) 543 << Name << Range; 544 PrintOverloadCandidates(Candidates, /*OnlyViable=*/true); 545 return true; 546 547 case OR_Deleted: 548 Diag(StartLoc, diag::err_ovl_deleted_call) 549 << Best->Function->isDeleted() 550 << Name << Range; 551 PrintOverloadCandidates(Candidates, /*OnlyViable=*/true); 552 return true; 553 } 554 assert(false && "Unreachable, bad result from BestViableFunction"); 555 return true; 556} 557 558 559/// DeclareGlobalNewDelete - Declare the global forms of operator new and 560/// delete. These are: 561/// @code 562/// void* operator new(std::size_t) throw(std::bad_alloc); 563/// void* operator new[](std::size_t) throw(std::bad_alloc); 564/// void operator delete(void *) throw(); 565/// void operator delete[](void *) throw(); 566/// @endcode 567/// Note that the placement and nothrow forms of new are *not* implicitly 568/// declared. Their use requires including \<new\>. 569void Sema::DeclareGlobalNewDelete() 570{ 571 if (GlobalNewDeleteDeclared) 572 return; 573 GlobalNewDeleteDeclared = true; 574 575 QualType VoidPtr = Context.getPointerType(Context.VoidTy); 576 QualType SizeT = Context.getSizeType(); 577 578 // FIXME: Exception specifications are not added. 579 DeclareGlobalAllocationFunction( 580 Context.DeclarationNames.getCXXOperatorName(OO_New), 581 VoidPtr, SizeT); 582 DeclareGlobalAllocationFunction( 583 Context.DeclarationNames.getCXXOperatorName(OO_Array_New), 584 VoidPtr, SizeT); 585 DeclareGlobalAllocationFunction( 586 Context.DeclarationNames.getCXXOperatorName(OO_Delete), 587 Context.VoidTy, VoidPtr); 588 DeclareGlobalAllocationFunction( 589 Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete), 590 Context.VoidTy, VoidPtr); 591} 592 593/// DeclareGlobalAllocationFunction - Declares a single implicit global 594/// allocation function if it doesn't already exist. 595void Sema::DeclareGlobalAllocationFunction(DeclarationName Name, 596 QualType Return, QualType Argument) 597{ 598 DeclContext *GlobalCtx = Context.getTranslationUnitDecl(); 599 600 // Check if this function is already declared. 601 { 602 DeclContext::lookup_iterator Alloc, AllocEnd; 603 for (llvm::tie(Alloc, AllocEnd) = GlobalCtx->lookup(Context, Name); 604 Alloc != AllocEnd; ++Alloc) { 605 // FIXME: Do we need to check for default arguments here? 606 FunctionDecl *Func = cast<FunctionDecl>(*Alloc); 607 if (Func->getNumParams() == 1 && 608 Context.getCanonicalType(Func->getParamDecl(0)->getType())==Argument) 609 return; 610 } 611 } 612 613 QualType FnType = Context.getFunctionType(Return, &Argument, 1, false, 0); 614 FunctionDecl *Alloc = 615 FunctionDecl::Create(Context, GlobalCtx, SourceLocation(), Name, 616 FnType, FunctionDecl::None, false, true, 617 SourceLocation()); 618 Alloc->setImplicit(); 619 ParmVarDecl *Param = ParmVarDecl::Create(Context, Alloc, SourceLocation(), 620 0, Argument, VarDecl::None, 0); 621 Alloc->setParams(Context, &Param, 1); 622 623 // FIXME: Also add this declaration to the IdentifierResolver, but 624 // make sure it is at the end of the chain to coincide with the 625 // global scope. 626 ((DeclContext *)TUScope->getEntity())->addDecl(Context, Alloc); 627} 628 629/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in: 630/// @code ::delete ptr; @endcode 631/// or 632/// @code delete [] ptr; @endcode 633Action::OwningExprResult 634Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal, 635 bool ArrayForm, ExprArg Operand) 636{ 637 // C++ 5.3.5p1: "The operand shall have a pointer type, or a class type 638 // having a single conversion function to a pointer type. The result has 639 // type void." 640 // DR599 amends "pointer type" to "pointer to object type" in both cases. 641 642 Expr *Ex = (Expr *)Operand.get(); 643 if (!Ex->isTypeDependent()) { 644 QualType Type = Ex->getType(); 645 646 if (Type->isRecordType()) { 647 // FIXME: Find that one conversion function and amend the type. 648 } 649 650 if (!Type->isPointerType()) 651 return ExprError(Diag(StartLoc, diag::err_delete_operand) 652 << Type << Ex->getSourceRange()); 653 654 QualType Pointee = Type->getAsPointerType()->getPointeeType(); 655 if (Pointee->isFunctionType() || Pointee->isVoidType()) 656 return ExprError(Diag(StartLoc, diag::err_delete_operand) 657 << Type << Ex->getSourceRange()); 658 else if (!Pointee->isDependentType() && 659 RequireCompleteType(StartLoc, Pointee, 660 diag::warn_delete_incomplete, 661 Ex->getSourceRange())) 662 return ExprError(); 663 664 // FIXME: Look up the correct operator delete overload and pass a pointer 665 // along. 666 // FIXME: Check access and ambiguity of operator delete and destructor. 667 } 668 669 Operand.release(); 670 return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm, 671 0, Ex, StartLoc)); 672} 673 674 675/// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a 676/// C++ if/switch/while/for statement. 677/// e.g: "if (int x = f()) {...}" 678Action::OwningExprResult 679Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc, 680 Declarator &D, 681 SourceLocation EqualLoc, 682 ExprArg AssignExprVal) { 683 assert(AssignExprVal.get() && "Null assignment expression"); 684 685 // C++ 6.4p2: 686 // The declarator shall not specify a function or an array. 687 // The type-specifier-seq shall not contain typedef and shall not declare a 688 // new class or enumeration. 689 690 assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef && 691 "Parser allowed 'typedef' as storage class of condition decl."); 692 693 QualType Ty = GetTypeForDeclarator(D, S); 694 695 if (Ty->isFunctionType()) { // The declarator shall not specify a function... 696 // We exit without creating a CXXConditionDeclExpr because a FunctionDecl 697 // would be created and CXXConditionDeclExpr wants a VarDecl. 698 return ExprError(Diag(StartLoc, diag::err_invalid_use_of_function_type) 699 << SourceRange(StartLoc, EqualLoc)); 700 } else if (Ty->isArrayType()) { // ...or an array. 701 Diag(StartLoc, diag::err_invalid_use_of_array_type) 702 << SourceRange(StartLoc, EqualLoc); 703 } else if (const RecordType *RT = Ty->getAsRecordType()) { 704 RecordDecl *RD = RT->getDecl(); 705 // The type-specifier-seq shall not declare a new class... 706 if (RD->isDefinition() && 707 (RD->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(RD)))) 708 Diag(RD->getLocation(), diag::err_type_defined_in_condition); 709 } else if (const EnumType *ET = Ty->getAsEnumType()) { 710 EnumDecl *ED = ET->getDecl(); 711 // ...or enumeration. 712 if (ED->isDefinition() && 713 (ED->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(ED)))) 714 Diag(ED->getLocation(), diag::err_type_defined_in_condition); 715 } 716 717 DeclPtrTy Dcl = ActOnDeclarator(S, D, DeclPtrTy()); 718 if (!Dcl) 719 return ExprError(); 720 AddInitializerToDecl(Dcl, move(AssignExprVal)); 721 722 // Mark this variable as one that is declared within a conditional. 723 // We know that the decl had to be a VarDecl because that is the only type of 724 // decl that can be assigned and the grammar requires an '='. 725 VarDecl *VD = cast<VarDecl>(Dcl.getAs<Decl>()); 726 VD->setDeclaredInCondition(true); 727 return Owned(new (Context) CXXConditionDeclExpr(StartLoc, EqualLoc, VD)); 728} 729 730/// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid. 731bool Sema::CheckCXXBooleanCondition(Expr *&CondExpr) { 732 // C++ 6.4p4: 733 // The value of a condition that is an initialized declaration in a statement 734 // other than a switch statement is the value of the declared variable 735 // implicitly converted to type bool. If that conversion is ill-formed, the 736 // program is ill-formed. 737 // The value of a condition that is an expression is the value of the 738 // expression, implicitly converted to bool. 739 // 740 return PerformContextuallyConvertToBool(CondExpr); 741} 742 743/// Helper function to determine whether this is the (deprecated) C++ 744/// conversion from a string literal to a pointer to non-const char or 745/// non-const wchar_t (for narrow and wide string literals, 746/// respectively). 747bool 748Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) { 749 // Look inside the implicit cast, if it exists. 750 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From)) 751 From = Cast->getSubExpr(); 752 753 // A string literal (2.13.4) that is not a wide string literal can 754 // be converted to an rvalue of type "pointer to char"; a wide 755 // string literal can be converted to an rvalue of type "pointer 756 // to wchar_t" (C++ 4.2p2). 757 if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From)) 758 if (const PointerType *ToPtrType = ToType->getAsPointerType()) 759 if (const BuiltinType *ToPointeeType 760 = ToPtrType->getPointeeType()->getAsBuiltinType()) { 761 // This conversion is considered only when there is an 762 // explicit appropriate pointer target type (C++ 4.2p2). 763 if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 && 764 ((StrLit->isWide() && ToPointeeType->isWideCharType()) || 765 (!StrLit->isWide() && 766 (ToPointeeType->getKind() == BuiltinType::Char_U || 767 ToPointeeType->getKind() == BuiltinType::Char_S)))) 768 return true; 769 } 770 771 return false; 772} 773 774/// PerformImplicitConversion - Perform an implicit conversion of the 775/// expression From to the type ToType. Returns true if there was an 776/// error, false otherwise. The expression From is replaced with the 777/// converted expression. Flavor is the kind of conversion we're 778/// performing, used in the error message. If @p AllowExplicit, 779/// explicit user-defined conversions are permitted. @p Elidable should be true 780/// when called for copies which may be elided (C++ 12.8p15). C++0x overload 781/// resolution works differently in that case. 782bool 783Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 784 const char *Flavor, bool AllowExplicit, 785 bool Elidable) 786{ 787 ImplicitConversionSequence ICS; 788 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 789 if (Elidable && getLangOptions().CPlusPlus0x) { 790 ICS = TryImplicitConversion(From, ToType, /*SuppressUserConversions*/false, 791 AllowExplicit, /*ForceRValue*/true); 792 } 793 if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) { 794 ICS = TryImplicitConversion(From, ToType, false, AllowExplicit); 795 } 796 return PerformImplicitConversion(From, ToType, ICS, Flavor); 797} 798 799/// PerformImplicitConversion - Perform an implicit conversion of the 800/// expression From to the type ToType using the pre-computed implicit 801/// conversion sequence ICS. Returns true if there was an error, false 802/// otherwise. The expression From is replaced with the converted 803/// expression. Flavor is the kind of conversion we're performing, 804/// used in the error message. 805bool 806Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 807 const ImplicitConversionSequence &ICS, 808 const char* Flavor) { 809 switch (ICS.ConversionKind) { 810 case ImplicitConversionSequence::StandardConversion: 811 if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor)) 812 return true; 813 break; 814 815 case ImplicitConversionSequence::UserDefinedConversion: 816 // FIXME: This is, of course, wrong. We'll need to actually call the 817 // constructor or conversion operator, and then cope with the standard 818 // conversions. 819 ImpCastExprToType(From, ToType.getNonReferenceType(), 820 ToType->isLValueReferenceType()); 821 return false; 822 823 case ImplicitConversionSequence::EllipsisConversion: 824 assert(false && "Cannot perform an ellipsis conversion"); 825 return false; 826 827 case ImplicitConversionSequence::BadConversion: 828 return true; 829 } 830 831 // Everything went well. 832 return false; 833} 834 835/// PerformImplicitConversion - Perform an implicit conversion of the 836/// expression From to the type ToType by following the standard 837/// conversion sequence SCS. Returns true if there was an error, false 838/// otherwise. The expression From is replaced with the converted 839/// expression. Flavor is the context in which we're performing this 840/// conversion, for use in error messages. 841bool 842Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 843 const StandardConversionSequence& SCS, 844 const char *Flavor) { 845 // Overall FIXME: we are recomputing too many types here and doing far too 846 // much extra work. What this means is that we need to keep track of more 847 // information that is computed when we try the implicit conversion initially, 848 // so that we don't need to recompute anything here. 849 QualType FromType = From->getType(); 850 851 if (SCS.CopyConstructor) { 852 // FIXME: Create a temporary object by calling the copy constructor. 853 ImpCastExprToType(From, ToType.getNonReferenceType(), 854 ToType->isLValueReferenceType()); 855 return false; 856 } 857 858 // Perform the first implicit conversion. 859 switch (SCS.First) { 860 case ICK_Identity: 861 case ICK_Lvalue_To_Rvalue: 862 // Nothing to do. 863 break; 864 865 case ICK_Array_To_Pointer: 866 FromType = Context.getArrayDecayedType(FromType); 867 ImpCastExprToType(From, FromType); 868 break; 869 870 case ICK_Function_To_Pointer: 871 if (Context.getCanonicalType(FromType) == Context.OverloadTy) { 872 FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true); 873 if (!Fn) 874 return true; 875 876 if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin())) 877 return true; 878 879 FixOverloadedFunctionReference(From, Fn); 880 FromType = From->getType(); 881 } 882 FromType = Context.getPointerType(FromType); 883 ImpCastExprToType(From, FromType); 884 break; 885 886 default: 887 assert(false && "Improper first standard conversion"); 888 break; 889 } 890 891 // Perform the second implicit conversion 892 switch (SCS.Second) { 893 case ICK_Identity: 894 // Nothing to do. 895 break; 896 897 case ICK_Integral_Promotion: 898 case ICK_Floating_Promotion: 899 case ICK_Complex_Promotion: 900 case ICK_Integral_Conversion: 901 case ICK_Floating_Conversion: 902 case ICK_Complex_Conversion: 903 case ICK_Floating_Integral: 904 case ICK_Complex_Real: 905 case ICK_Compatible_Conversion: 906 // FIXME: Go deeper to get the unqualified type! 907 FromType = ToType.getUnqualifiedType(); 908 ImpCastExprToType(From, FromType); 909 break; 910 911 case ICK_Pointer_Conversion: 912 if (SCS.IncompatibleObjC) { 913 // Diagnose incompatible Objective-C conversions 914 Diag(From->getSourceRange().getBegin(), 915 diag::ext_typecheck_convert_incompatible_pointer) 916 << From->getType() << ToType << Flavor 917 << From->getSourceRange(); 918 } 919 920 if (CheckPointerConversion(From, ToType)) 921 return true; 922 ImpCastExprToType(From, ToType); 923 break; 924 925 case ICK_Pointer_Member: 926 if (CheckMemberPointerConversion(From, ToType)) 927 return true; 928 ImpCastExprToType(From, ToType); 929 break; 930 931 case ICK_Boolean_Conversion: 932 FromType = Context.BoolTy; 933 ImpCastExprToType(From, FromType); 934 break; 935 936 default: 937 assert(false && "Improper second standard conversion"); 938 break; 939 } 940 941 switch (SCS.Third) { 942 case ICK_Identity: 943 // Nothing to do. 944 break; 945 946 case ICK_Qualification: 947 // FIXME: Not sure about lvalue vs rvalue here in the presence of rvalue 948 // references. 949 ImpCastExprToType(From, ToType.getNonReferenceType(), 950 ToType->isLValueReferenceType()); 951 break; 952 953 default: 954 assert(false && "Improper second standard conversion"); 955 break; 956 } 957 958 return false; 959} 960 961Sema::OwningExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT, 962 SourceLocation KWLoc, 963 SourceLocation LParen, 964 TypeTy *Ty, 965 SourceLocation RParen) { 966 // FIXME: Some of the type traits have requirements. Interestingly, only the 967 // __is_base_of requirement is explicitly stated to be diagnosed. Indeed, G++ 968 // accepts __is_pod(Incomplete) without complaints, and claims that the type 969 // is indeed a POD. 970 971 // There is no point in eagerly computing the value. The traits are designed 972 // to be used from type trait templates, so Ty will be a template parameter 973 // 99% of the time. 974 return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT, 975 QualType::getFromOpaquePtr(Ty), 976 RParen, Context.BoolTy)); 977} 978 979QualType Sema::CheckPointerToMemberOperands( 980 Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect) 981{ 982 const char *OpSpelling = isIndirect ? "->*" : ".*"; 983 // C++ 5.5p2 984 // The binary operator .* [p3: ->*] binds its second operand, which shall 985 // be of type "pointer to member of T" (where T is a completely-defined 986 // class type) [...] 987 QualType RType = rex->getType(); 988 const MemberPointerType *MemPtr = RType->getAsMemberPointerType(); 989 if (!MemPtr) { 990 Diag(Loc, diag::err_bad_memptr_rhs) 991 << OpSpelling << RType << rex->getSourceRange(); 992 return QualType(); 993 } 994 995 QualType Class(MemPtr->getClass(), 0); 996 997 // C++ 5.5p2 998 // [...] to its first operand, which shall be of class T or of a class of 999 // which T is an unambiguous and accessible base class. [p3: a pointer to 1000 // such a class] 1001 QualType LType = lex->getType(); 1002 if (isIndirect) { 1003 if (const PointerType *Ptr = LType->getAsPointerType()) 1004 LType = Ptr->getPointeeType().getNonReferenceType(); 1005 else { 1006 Diag(Loc, diag::err_bad_memptr_lhs) 1007 << OpSpelling << 1 << LType << lex->getSourceRange(); 1008 return QualType(); 1009 } 1010 } 1011 1012 if (Context.getCanonicalType(Class).getUnqualifiedType() != 1013 Context.getCanonicalType(LType).getUnqualifiedType()) { 1014 BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, 1015 /*DetectVirtual=*/false); 1016 // FIXME: Would it be useful to print full ambiguity paths, or is that 1017 // overkill? 1018 if (!IsDerivedFrom(LType, Class, Paths) || 1019 Paths.isAmbiguous(Context.getCanonicalType(Class))) { 1020 Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling 1021 << (int)isIndirect << lex->getType() << lex->getSourceRange(); 1022 return QualType(); 1023 } 1024 } 1025 1026 // C++ 5.5p2 1027 // The result is an object or a function of the type specified by the 1028 // second operand. 1029 // The cv qualifiers are the union of those in the pointer and the left side, 1030 // in accordance with 5.5p5 and 5.2.5. 1031 // FIXME: This returns a dereferenced member function pointer as a normal 1032 // function type. However, the only operation valid on such functions is 1033 // calling them. There's also a GCC extension to get a function pointer to the 1034 // thing, which is another complication, because this type - unlike the type 1035 // that is the result of this expression - takes the class as the first 1036 // argument. 1037 // We probably need a "MemberFunctionClosureType" or something like that. 1038 QualType Result = MemPtr->getPointeeType(); 1039 if (LType.isConstQualified()) 1040 Result.addConst(); 1041 if (LType.isVolatileQualified()) 1042 Result.addVolatile(); 1043 return Result; 1044} 1045 1046/// \brief Get the target type of a standard or user-defined conversion. 1047static QualType TargetType(const ImplicitConversionSequence &ICS) { 1048 assert((ICS.ConversionKind == 1049 ImplicitConversionSequence::StandardConversion || 1050 ICS.ConversionKind == 1051 ImplicitConversionSequence::UserDefinedConversion) && 1052 "function only valid for standard or user-defined conversions"); 1053 if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion) 1054 return QualType::getFromOpaquePtr(ICS.Standard.ToTypePtr); 1055 return QualType::getFromOpaquePtr(ICS.UserDefined.After.ToTypePtr); 1056} 1057 1058/// \brief Try to convert a type to another according to C++0x 5.16p3. 1059/// 1060/// This is part of the parameter validation for the ? operator. If either 1061/// value operand is a class type, the two operands are attempted to be 1062/// converted to each other. This function does the conversion in one direction. 1063/// It emits a diagnostic and returns true only if it finds an ambiguous 1064/// conversion. 1065static bool TryClassUnification(Sema &Self, Expr *From, Expr *To, 1066 SourceLocation QuestionLoc, 1067 ImplicitConversionSequence &ICS) 1068{ 1069 // C++0x 5.16p3 1070 // The process for determining whether an operand expression E1 of type T1 1071 // can be converted to match an operand expression E2 of type T2 is defined 1072 // as follows: 1073 // -- If E2 is an lvalue: 1074 if (To->isLvalue(Self.Context) == Expr::LV_Valid) { 1075 // E1 can be converted to match E2 if E1 can be implicitly converted to 1076 // type "lvalue reference to T2", subject to the constraint that in the 1077 // conversion the reference must bind directly to E1. 1078 if (!Self.CheckReferenceInit(From, 1079 Self.Context.getLValueReferenceType(To->getType()), 1080 &ICS)) 1081 { 1082 assert((ICS.ConversionKind == 1083 ImplicitConversionSequence::StandardConversion || 1084 ICS.ConversionKind == 1085 ImplicitConversionSequence::UserDefinedConversion) && 1086 "expected a definite conversion"); 1087 bool DirectBinding = 1088 ICS.ConversionKind == ImplicitConversionSequence::StandardConversion ? 1089 ICS.Standard.DirectBinding : ICS.UserDefined.After.DirectBinding; 1090 if (DirectBinding) 1091 return false; 1092 } 1093 } 1094 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 1095 // -- If E2 is an rvalue, or if the conversion above cannot be done: 1096 // -- if E1 and E2 have class type, and the underlying class types are 1097 // the same or one is a base class of the other: 1098 QualType FTy = From->getType(); 1099 QualType TTy = To->getType(); 1100 const RecordType *FRec = FTy->getAsRecordType(); 1101 const RecordType *TRec = TTy->getAsRecordType(); 1102 bool FDerivedFromT = FRec && TRec && Self.IsDerivedFrom(FTy, TTy); 1103 if (FRec && TRec && (FRec == TRec || 1104 FDerivedFromT || Self.IsDerivedFrom(TTy, FTy))) { 1105 // E1 can be converted to match E2 if the class of T2 is the 1106 // same type as, or a base class of, the class of T1, and 1107 // [cv2 > cv1]. 1108 if ((FRec == TRec || FDerivedFromT) && TTy.isAtLeastAsQualifiedAs(FTy)) { 1109 // Could still fail if there's no copy constructor. 1110 // FIXME: Is this a hard error then, or just a conversion failure? The 1111 // standard doesn't say. 1112 ICS = Self.TryCopyInitialization(From, TTy); 1113 } 1114 } else { 1115 // -- Otherwise: E1 can be converted to match E2 if E1 can be 1116 // implicitly converted to the type that expression E2 would have 1117 // if E2 were converted to an rvalue. 1118 // First find the decayed type. 1119 if (TTy->isFunctionType()) 1120 TTy = Self.Context.getPointerType(TTy); 1121 else if(TTy->isArrayType()) 1122 TTy = Self.Context.getArrayDecayedType(TTy); 1123 1124 // Now try the implicit conversion. 1125 // FIXME: This doesn't detect ambiguities. 1126 ICS = Self.TryImplicitConversion(From, TTy); 1127 } 1128 return false; 1129} 1130 1131/// \brief Try to find a common type for two according to C++0x 5.16p5. 1132/// 1133/// This is part of the parameter validation for the ? operator. If either 1134/// value operand is a class type, overload resolution is used to find a 1135/// conversion to a common type. 1136static bool FindConditionalOverload(Sema &Self, Expr *&LHS, Expr *&RHS, 1137 SourceLocation Loc) { 1138 Expr *Args[2] = { LHS, RHS }; 1139 OverloadCandidateSet CandidateSet; 1140 Self.AddBuiltinOperatorCandidates(OO_Conditional, Args, 2, CandidateSet); 1141 1142 OverloadCandidateSet::iterator Best; 1143 switch (Self.BestViableFunction(CandidateSet, Best)) { 1144 case Sema::OR_Success: 1145 // We found a match. Perform the conversions on the arguments and move on. 1146 if (Self.PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0], 1147 Best->Conversions[0], "converting") || 1148 Self.PerformImplicitConversion(RHS, Best->BuiltinTypes.ParamTypes[1], 1149 Best->Conversions[1], "converting")) 1150 break; 1151 return false; 1152 1153 case Sema::OR_No_Viable_Function: 1154 Self.Diag(Loc, diag::err_typecheck_cond_incompatible_operands) 1155 << LHS->getType() << RHS->getType() 1156 << LHS->getSourceRange() << RHS->getSourceRange(); 1157 return true; 1158 1159 case Sema::OR_Ambiguous: 1160 Self.Diag(Loc, diag::err_conditional_ambiguous_ovl) 1161 << LHS->getType() << RHS->getType() 1162 << LHS->getSourceRange() << RHS->getSourceRange(); 1163 // FIXME: Print the possible common types by printing the return types of 1164 // the viable candidates. 1165 break; 1166 1167 case Sema::OR_Deleted: 1168 assert(false && "Conditional operator has only built-in overloads"); 1169 break; 1170 } 1171 return true; 1172} 1173 1174/// \brief Perform an "extended" implicit conversion as returned by 1175/// TryClassUnification. 1176/// 1177/// TryClassUnification generates ICSs that include reference bindings. 1178/// PerformImplicitConversion is not suitable for this; it chokes if the 1179/// second part of a standard conversion is ICK_DerivedToBase. This function 1180/// handles the reference binding specially. 1181static bool ConvertForConditional(Sema &Self, Expr *&E, 1182 const ImplicitConversionSequence &ICS) 1183{ 1184 if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion && 1185 ICS.Standard.ReferenceBinding) { 1186 assert(ICS.Standard.DirectBinding && 1187 "TryClassUnification should never generate indirect ref bindings"); 1188 // FIXME: CheckReferenceInit should be able to reuse the ICS instead of 1189 // redoing all the work. 1190 return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType( 1191 TargetType(ICS))); 1192 } 1193 if (ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion && 1194 ICS.UserDefined.After.ReferenceBinding) { 1195 assert(ICS.UserDefined.After.DirectBinding && 1196 "TryClassUnification should never generate indirect ref bindings"); 1197 return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType( 1198 TargetType(ICS))); 1199 } 1200 if (Self.PerformImplicitConversion(E, TargetType(ICS), ICS, "converting")) 1201 return true; 1202 return false; 1203} 1204 1205/// \brief Check the operands of ?: under C++ semantics. 1206/// 1207/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y 1208/// extension. In this case, LHS == Cond. (But they're not aliases.) 1209QualType Sema::CXXCheckConditionalOperands(Expr *&Cond, Expr *&LHS, Expr *&RHS, 1210 SourceLocation QuestionLoc) { 1211 // FIXME: Handle C99's complex types, vector types, block pointers and Obj-C++ 1212 // interface pointers. 1213 1214 // C++0x 5.16p1 1215 // The first expression is contextually converted to bool. 1216 if (!Cond->isTypeDependent()) { 1217 if (CheckCXXBooleanCondition(Cond)) 1218 return QualType(); 1219 } 1220 1221 // Either of the arguments dependent? 1222 if (LHS->isTypeDependent() || RHS->isTypeDependent()) 1223 return Context.DependentTy; 1224 1225 // C++0x 5.16p2 1226 // If either the second or the third operand has type (cv) void, ... 1227 QualType LTy = LHS->getType(); 1228 QualType RTy = RHS->getType(); 1229 bool LVoid = LTy->isVoidType(); 1230 bool RVoid = RTy->isVoidType(); 1231 if (LVoid || RVoid) { 1232 // ... then the [l2r] conversions are performed on the second and third 1233 // operands ... 1234 DefaultFunctionArrayConversion(LHS); 1235 DefaultFunctionArrayConversion(RHS); 1236 LTy = LHS->getType(); 1237 RTy = RHS->getType(); 1238 1239 // ... and one of the following shall hold: 1240 // -- The second or the third operand (but not both) is a throw- 1241 // expression; the result is of the type of the other and is an rvalue. 1242 bool LThrow = isa<CXXThrowExpr>(LHS); 1243 bool RThrow = isa<CXXThrowExpr>(RHS); 1244 if (LThrow && !RThrow) 1245 return RTy; 1246 if (RThrow && !LThrow) 1247 return LTy; 1248 1249 // -- Both the second and third operands have type void; the result is of 1250 // type void and is an rvalue. 1251 if (LVoid && RVoid) 1252 return Context.VoidTy; 1253 1254 // Neither holds, error. 1255 Diag(QuestionLoc, diag::err_conditional_void_nonvoid) 1256 << (LVoid ? RTy : LTy) << (LVoid ? 0 : 1) 1257 << LHS->getSourceRange() << RHS->getSourceRange(); 1258 return QualType(); 1259 } 1260 1261 // Neither is void. 1262 1263 // C++0x 5.16p3 1264 // Otherwise, if the second and third operand have different types, and 1265 // either has (cv) class type, and attempt is made to convert each of those 1266 // operands to the other. 1267 if (Context.getCanonicalType(LTy) != Context.getCanonicalType(RTy) && 1268 (LTy->isRecordType() || RTy->isRecordType())) { 1269 ImplicitConversionSequence ICSLeftToRight, ICSRightToLeft; 1270 // These return true if a single direction is already ambiguous. 1271 if (TryClassUnification(*this, LHS, RHS, QuestionLoc, ICSLeftToRight)) 1272 return QualType(); 1273 if (TryClassUnification(*this, RHS, LHS, QuestionLoc, ICSRightToLeft)) 1274 return QualType(); 1275 1276 bool HaveL2R = ICSLeftToRight.ConversionKind != 1277 ImplicitConversionSequence::BadConversion; 1278 bool HaveR2L = ICSRightToLeft.ConversionKind != 1279 ImplicitConversionSequence::BadConversion; 1280 // If both can be converted, [...] the program is ill-formed. 1281 if (HaveL2R && HaveR2L) { 1282 Diag(QuestionLoc, diag::err_conditional_ambiguous) 1283 << LTy << RTy << LHS->getSourceRange() << RHS->getSourceRange(); 1284 return QualType(); 1285 } 1286 1287 // If exactly one conversion is possible, that conversion is applied to 1288 // the chosen operand and the converted operands are used in place of the 1289 // original operands for the remainder of this section. 1290 if (HaveL2R) { 1291 if (ConvertForConditional(*this, LHS, ICSLeftToRight)) 1292 return QualType(); 1293 LTy = LHS->getType(); 1294 } else if (HaveR2L) { 1295 if (ConvertForConditional(*this, RHS, ICSRightToLeft)) 1296 return QualType(); 1297 RTy = RHS->getType(); 1298 } 1299 } 1300 1301 // C++0x 5.16p4 1302 // If the second and third operands are lvalues and have the same type, 1303 // the result is of that type [...] 1304 bool Same = Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy); 1305 if (Same && LHS->isLvalue(Context) == Expr::LV_Valid && 1306 RHS->isLvalue(Context) == Expr::LV_Valid) 1307 return LTy; 1308 1309 // C++0x 5.16p5 1310 // Otherwise, the result is an rvalue. If the second and third operands 1311 // do not have the same type, and either has (cv) class type, ... 1312 if (!Same && (LTy->isRecordType() || RTy->isRecordType())) { 1313 // ... overload resolution is used to determine the conversions (if any) 1314 // to be applied to the operands. If the overload resolution fails, the 1315 // program is ill-formed. 1316 if (FindConditionalOverload(*this, LHS, RHS, QuestionLoc)) 1317 return QualType(); 1318 } 1319 1320 // C++0x 5.16p6 1321 // LValue-to-rvalue, array-to-pointer, and function-to-pointer standard 1322 // conversions are performed on the second and third operands. 1323 DefaultFunctionArrayConversion(LHS); 1324 DefaultFunctionArrayConversion(RHS); 1325 LTy = LHS->getType(); 1326 RTy = RHS->getType(); 1327 1328 // After those conversions, one of the following shall hold: 1329 // -- The second and third operands have the same type; the result 1330 // is of that type. 1331 if (Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy)) 1332 return LTy; 1333 1334 // -- The second and third operands have arithmetic or enumeration type; 1335 // the usual arithmetic conversions are performed to bring them to a 1336 // common type, and the result is of that type. 1337 if (LTy->isArithmeticType() && RTy->isArithmeticType()) { 1338 UsualArithmeticConversions(LHS, RHS); 1339 return LHS->getType(); 1340 } 1341 1342 // -- The second and third operands have pointer type, or one has pointer 1343 // type and the other is a null pointer constant; pointer conversions 1344 // and qualification conversions are performed to bring them to their 1345 // composite pointer type. The result is of the composite pointer type. 1346 QualType Composite = FindCompositePointerType(LHS, RHS); 1347 if (!Composite.isNull()) 1348 return Composite; 1349 1350 // Fourth bullet is same for pointers-to-member. However, the possible 1351 // conversions are far more limited: we have null-to-pointer, upcast of 1352 // containing class, and second-level cv-ness. 1353 // cv-ness is not a union, but must match one of the two operands. (Which, 1354 // frankly, is stupid.) 1355 const MemberPointerType *LMemPtr = LTy->getAsMemberPointerType(); 1356 const MemberPointerType *RMemPtr = RTy->getAsMemberPointerType(); 1357 if (LMemPtr && RHS->isNullPointerConstant(Context)) { 1358 ImpCastExprToType(RHS, LTy); 1359 return LTy; 1360 } 1361 if (RMemPtr && LHS->isNullPointerConstant(Context)) { 1362 ImpCastExprToType(LHS, RTy); 1363 return RTy; 1364 } 1365 if (LMemPtr && RMemPtr) { 1366 QualType LPointee = LMemPtr->getPointeeType(); 1367 QualType RPointee = RMemPtr->getPointeeType(); 1368 // First, we check that the unqualified pointee type is the same. If it's 1369 // not, there's no conversion that will unify the two pointers. 1370 if (Context.getCanonicalType(LPointee).getUnqualifiedType() == 1371 Context.getCanonicalType(RPointee).getUnqualifiedType()) { 1372 // Second, we take the greater of the two cv qualifications. If neither 1373 // is greater than the other, the conversion is not possible. 1374 unsigned Q = LPointee.getCVRQualifiers() | RPointee.getCVRQualifiers(); 1375 if (Q == LPointee.getCVRQualifiers() || Q == RPointee.getCVRQualifiers()){ 1376 // Third, we check if either of the container classes is derived from 1377 // the other. 1378 QualType LContainer(LMemPtr->getClass(), 0); 1379 QualType RContainer(RMemPtr->getClass(), 0); 1380 QualType MoreDerived; 1381 if (Context.getCanonicalType(LContainer) == 1382 Context.getCanonicalType(RContainer)) 1383 MoreDerived = LContainer; 1384 else if (IsDerivedFrom(LContainer, RContainer)) 1385 MoreDerived = LContainer; 1386 else if (IsDerivedFrom(RContainer, LContainer)) 1387 MoreDerived = RContainer; 1388 1389 if (!MoreDerived.isNull()) { 1390 // The type 'Q Pointee (MoreDerived::*)' is the common type. 1391 // We don't use ImpCastExprToType here because this could still fail 1392 // for ambiguous or inaccessible conversions. 1393 QualType Common = Context.getMemberPointerType( 1394 LPointee.getQualifiedType(Q), MoreDerived.getTypePtr()); 1395 if (PerformImplicitConversion(LHS, Common, "converting")) 1396 return QualType(); 1397 if (PerformImplicitConversion(RHS, Common, "converting")) 1398 return QualType(); 1399 return Common; 1400 } 1401 } 1402 } 1403 } 1404 1405 Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands) 1406 << LHS->getType() << RHS->getType() 1407 << LHS->getSourceRange() << RHS->getSourceRange(); 1408 return QualType(); 1409} 1410 1411/// \brief Find a merged pointer type and convert the two expressions to it. 1412/// 1413/// This finds the composite pointer type for @p E1 and @p E2 according to 1414/// C++0x 5.9p2. It converts both expressions to this type and returns it. 1415/// It does not emit diagnostics. 1416QualType Sema::FindCompositePointerType(Expr *&E1, Expr *&E2) { 1417 assert(getLangOptions().CPlusPlus && "This function assumes C++"); 1418 QualType T1 = E1->getType(), T2 = E2->getType(); 1419 if(!T1->isPointerType() && !T2->isPointerType()) 1420 return QualType(); 1421 1422 // C++0x 5.9p2 1423 // Pointer conversions and qualification conversions are performed on 1424 // pointer operands to bring them to their composite pointer type. If 1425 // one operand is a null pointer constant, the composite pointer type is 1426 // the type of the other operand. 1427 if (E1->isNullPointerConstant(Context)) { 1428 ImpCastExprToType(E1, T2); 1429 return T2; 1430 } 1431 if (E2->isNullPointerConstant(Context)) { 1432 ImpCastExprToType(E2, T1); 1433 return T1; 1434 } 1435 // Now both have to be pointers. 1436 if(!T1->isPointerType() || !T2->isPointerType()) 1437 return QualType(); 1438 1439 // Otherwise, of one of the operands has type "pointer to cv1 void," then 1440 // the other has type "pointer to cv2 T" and the composite pointer type is 1441 // "pointer to cv12 void," where cv12 is the union of cv1 and cv2. 1442 // Otherwise, the composite pointer type is a pointer type similar to the 1443 // type of one of the operands, with a cv-qualification signature that is 1444 // the union of the cv-qualification signatures of the operand types. 1445 // In practice, the first part here is redundant; it's subsumed by the second. 1446 // What we do here is, we build the two possible composite types, and try the 1447 // conversions in both directions. If only one works, or if the two composite 1448 // types are the same, we have succeeded. 1449 llvm::SmallVector<unsigned, 4> QualifierUnion; 1450 QualType Composite1 = T1, Composite2 = T2; 1451 const PointerType *Ptr1, *Ptr2; 1452 while ((Ptr1 = Composite1->getAsPointerType()) && 1453 (Ptr2 = Composite2->getAsPointerType())) { 1454 Composite1 = Ptr1->getPointeeType(); 1455 Composite2 = Ptr2->getPointeeType(); 1456 QualifierUnion.push_back( 1457 Composite1.getCVRQualifiers() | Composite2.getCVRQualifiers()); 1458 } 1459 // Rewrap the composites as pointers with the union CVRs. 1460 for (llvm::SmallVector<unsigned, 4>::iterator I = QualifierUnion.begin(), 1461 E = QualifierUnion.end(); I != E; ++I) { 1462 Composite1 = Context.getPointerType(Composite1.getQualifiedType(*I)); 1463 Composite2 = Context.getPointerType(Composite2.getQualifiedType(*I)); 1464 } 1465 1466 ImplicitConversionSequence E1ToC1 = TryImplicitConversion(E1, Composite1); 1467 ImplicitConversionSequence E2ToC1 = TryImplicitConversion(E2, Composite1); 1468 ImplicitConversionSequence E1ToC2, E2ToC2; 1469 E1ToC2.ConversionKind = ImplicitConversionSequence::BadConversion; 1470 E2ToC2.ConversionKind = ImplicitConversionSequence::BadConversion; 1471 if (Context.getCanonicalType(Composite1) != 1472 Context.getCanonicalType(Composite2)) { 1473 E1ToC2 = TryImplicitConversion(E1, Composite2); 1474 E2ToC2 = TryImplicitConversion(E2, Composite2); 1475 } 1476 1477 bool ToC1Viable = E1ToC1.ConversionKind != 1478 ImplicitConversionSequence::BadConversion 1479 && E2ToC1.ConversionKind != 1480 ImplicitConversionSequence::BadConversion; 1481 bool ToC2Viable = E1ToC2.ConversionKind != 1482 ImplicitConversionSequence::BadConversion 1483 && E2ToC2.ConversionKind != 1484 ImplicitConversionSequence::BadConversion; 1485 if (ToC1Viable && !ToC2Viable) { 1486 if (!PerformImplicitConversion(E1, Composite1, E1ToC1, "converting") && 1487 !PerformImplicitConversion(E2, Composite1, E2ToC1, "converting")) 1488 return Composite1; 1489 } 1490 if (ToC2Viable && !ToC1Viable) { 1491 if (!PerformImplicitConversion(E1, Composite2, E1ToC2, "converting") && 1492 !PerformImplicitConversion(E2, Composite2, E2ToC2, "converting")) 1493 return Composite2; 1494 } 1495 return QualType(); 1496} 1497