//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements semantic analysis for C++ expressions. // //===----------------------------------------------------------------------===// #include "SemaInherit.h" #include "Sema.h" #include "clang/AST/ExprCXX.h" #include "clang/AST/ASTContext.h" #include "clang/Parse/DeclSpec.h" #include "clang/Lex/Preprocessor.h" #include "clang/Basic/TargetInfo.h" #include "llvm/ADT/STLExtras.h" using namespace clang; /// ActOnCXXConversionFunctionExpr - Parse a C++ conversion function /// name (e.g., operator void const *) as an expression. This is /// very similar to ActOnIdentifierExpr, except that instead of /// providing an identifier the parser provides the type of the /// conversion function. Sema::OwningExprResult Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc, TypeTy *Ty, bool HasTrailingLParen, const CXXScopeSpec &SS, bool isAddressOfOperand) { QualType ConvType = QualType::getFromOpaquePtr(Ty); QualType ConvTypeCanon = Context.getCanonicalType(ConvType); DeclarationName ConvName = Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon); return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen, &SS, isAddressOfOperand); } /// ActOnCXXOperatorFunctionIdExpr - Parse a C++ overloaded operator /// name (e.g., @c operator+ ) as an expression. This is very /// similar to ActOnIdentifierExpr, except that instead of providing /// an identifier the parser provides the kind of overloaded /// operator that was parsed. Sema::OwningExprResult Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc, OverloadedOperatorKind Op, bool HasTrailingLParen, const CXXScopeSpec &SS, bool isAddressOfOperand) { DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op); return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS, isAddressOfOperand); } /// ActOnCXXTypeidOfType - Parse typeid( type-id ). Action::OwningExprResult Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc, bool isType, void *TyOrExpr, SourceLocation RParenLoc) { NamespaceDecl *StdNs = GetStdNamespace(); if (!StdNs) return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid)); IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info"); Decl *TypeInfoDecl = LookupQualifiedName(StdNs, TypeInfoII, LookupTagName); RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null(TypeInfoDecl); if (!TypeInfoRecordDecl) return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid)); QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl); return Owned(new (Context) CXXTypeidExpr(isType, TyOrExpr, TypeInfoType.withConst(), SourceRange(OpLoc, RParenLoc))); } /// ActOnCXXBoolLiteral - Parse {true,false} literals. Action::OwningExprResult Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) { assert((Kind == tok::kw_true || Kind == tok::kw_false) && "Unknown C++ Boolean value!"); return Owned(new (Context) CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc)); } /// ActOnCXXNullPtrLiteral - Parse 'nullptr'. Action::OwningExprResult Sema::ActOnCXXNullPtrLiteral(SourceLocation Loc) { return Owned(new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc)); } /// ActOnCXXThrow - Parse throw expressions. Action::OwningExprResult Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprArg E) { Expr *Ex = E.takeAs(); if (Ex && !Ex->isTypeDependent() && CheckCXXThrowOperand(OpLoc, Ex)) return ExprError(); return Owned(new (Context) CXXThrowExpr(Ex, Context.VoidTy, OpLoc)); } /// CheckCXXThrowOperand - Validate the operand of a throw. bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) { // C++ [except.throw]p3: // [...] adjusting the type from "array of T" or "function returning T" // to "pointer to T" or "pointer to function returning T", [...] DefaultFunctionArrayConversion(E); // If the type of the exception would be an incomplete type or a pointer // to an incomplete type other than (cv) void the program is ill-formed. QualType Ty = E->getType(); int isPointer = 0; if (const PointerType* Ptr = Ty->getAsPointerType()) { Ty = Ptr->getPointeeType(); isPointer = 1; } if (!isPointer || !Ty->isVoidType()) { if (RequireCompleteType(ThrowLoc, Ty, isPointer ? diag::err_throw_incomplete_ptr : diag::err_throw_incomplete, E->getSourceRange(), SourceRange(), QualType())) return true; } // FIXME: Construct a temporary here. return false; } Action::OwningExprResult Sema::ActOnCXXThis(SourceLocation ThisLoc) { /// C++ 9.3.2: In the body of a non-static member function, the keyword this /// is a non-lvalue expression whose value is the address of the object for /// which the function is called. if (!isa(CurContext)) return ExprError(Diag(ThisLoc, diag::err_invalid_this_use)); if (CXXMethodDecl *MD = dyn_cast(CurContext)) if (MD->isInstance()) return Owned(new (Context) CXXThisExpr(ThisLoc, MD->getThisType(Context))); return ExprError(Diag(ThisLoc, diag::err_invalid_this_use)); } /// ActOnCXXTypeConstructExpr - Parse construction of a specified type. /// Can be interpreted either as function-style casting ("int(x)") /// or class type construction ("ClassType(x,y,z)") /// or creation of a value-initialized type ("int()"). Action::OwningExprResult Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep, SourceLocation LParenLoc, MultiExprArg exprs, SourceLocation *CommaLocs, SourceLocation RParenLoc) { assert(TypeRep && "Missing type!"); QualType Ty = QualType::getFromOpaquePtr(TypeRep); unsigned NumExprs = exprs.size(); Expr **Exprs = (Expr**)exprs.get(); SourceLocation TyBeginLoc = TypeRange.getBegin(); SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc); if (Ty->isDependentType() || CallExpr::hasAnyTypeDependentArguments(Exprs, NumExprs)) { exprs.release(); // FIXME: Is this correct? CXXTempVarDecl *Temp = CXXTempVarDecl::Create(Context, CurContext, Ty); return Owned(new (Context) CXXTemporaryObjectExpr(Context, Temp, 0, Ty, TyBeginLoc, Exprs, NumExprs, RParenLoc)); } // C++ [expr.type.conv]p1: // If the expression list is a single expression, the type conversion // expression is equivalent (in definedness, and if defined in meaning) to the // corresponding cast expression. // if (NumExprs == 1) { if (CheckCastTypes(TypeRange, Ty, Exprs[0])) return ExprError(); exprs.release(); return Owned(new (Context) CXXFunctionalCastExpr(Ty.getNonReferenceType(), Ty, TyBeginLoc, Exprs[0], RParenLoc)); } if (const RecordType *RT = Ty->getAsRecordType()) { CXXRecordDecl *Record = cast(RT->getDecl()); if (NumExprs > 1 || Record->hasUserDeclaredConstructor()) { CXXConstructorDecl *Constructor = PerformInitializationByConstructor(Ty, Exprs, NumExprs, TypeRange.getBegin(), SourceRange(TypeRange.getBegin(), RParenLoc), DeclarationName(), IK_Direct); if (!Constructor) return ExprError(); CXXTempVarDecl *Temp = CXXTempVarDecl::Create(Context, CurContext, Ty); exprs.release(); return Owned(new (Context) CXXTemporaryObjectExpr(Context, Temp, Constructor, Ty, TyBeginLoc, Exprs, NumExprs, RParenLoc)); } // Fall through to value-initialize an object of class type that // doesn't have a user-declared default constructor. } // C++ [expr.type.conv]p1: // If the expression list specifies more than a single value, the type shall // be a class with a suitably declared constructor. // if (NumExprs > 1) return ExprError(Diag(CommaLocs[0], diag::err_builtin_func_cast_more_than_one_arg) << FullRange); assert(NumExprs == 0 && "Expected 0 expressions"); // C++ [expr.type.conv]p2: // The expression T(), where T is a simple-type-specifier for a non-array // complete object type or the (possibly cv-qualified) void type, creates an // rvalue of the specified type, which is value-initialized. // if (Ty->isArrayType()) return ExprError(Diag(TyBeginLoc, diag::err_value_init_for_array_type) << FullRange); if (!Ty->isDependentType() && !Ty->isVoidType() && RequireCompleteType(TyBeginLoc, Ty, diag::err_invalid_incomplete_type_use, FullRange)) return ExprError(); if (RequireNonAbstractType(TyBeginLoc, Ty, diag::err_allocation_of_abstract_type)) return ExprError(); exprs.release(); return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc)); } /// ActOnCXXNew - Parsed a C++ 'new' expression (C++ 5.3.4), as in e.g.: /// @code new (memory) int[size][4] @endcode /// or /// @code ::new Foo(23, "hello") @endcode /// For the interpretation of this heap of arguments, consult the base version. Action::OwningExprResult Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal, SourceLocation PlacementLParen, MultiExprArg PlacementArgs, SourceLocation PlacementRParen, bool ParenTypeId, Declarator &D, SourceLocation ConstructorLParen, MultiExprArg ConstructorArgs, SourceLocation ConstructorRParen) { Expr *ArraySize = 0; unsigned Skip = 0; // If the specified type is an array, unwrap it and save the expression. if (D.getNumTypeObjects() > 0 && D.getTypeObject(0).Kind == DeclaratorChunk::Array) { DeclaratorChunk &Chunk = D.getTypeObject(0); if (Chunk.Arr.hasStatic) return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new) << D.getSourceRange()); if (!Chunk.Arr.NumElts) return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size) << D.getSourceRange()); ArraySize = static_cast(Chunk.Arr.NumElts); Skip = 1; } QualType AllocType = GetTypeForDeclarator(D, /*Scope=*/0, Skip); if (D.isInvalidType()) return ExprError(); if (CheckAllocatedType(AllocType, D)) return ExprError(); QualType ResultType = AllocType->isDependentType() ? Context.DependentTy : Context.getPointerType(AllocType); // That every array dimension except the first is constant was already // checked by the type check above. // C++ 5.3.4p6: "The expression in a direct-new-declarator shall have integral // or enumeration type with a non-negative value." if (ArraySize && !ArraySize->isTypeDependent()) { QualType SizeType = ArraySize->getType(); if (!SizeType->isIntegralType() && !SizeType->isEnumeralType()) return ExprError(Diag(ArraySize->getSourceRange().getBegin(), diag::err_array_size_not_integral) << SizeType << ArraySize->getSourceRange()); // Let's see if this is a constant < 0. If so, we reject it out of hand. // We don't care about special rules, so we tell the machinery it's not // evaluated - it gives us a result in more cases. if (!ArraySize->isValueDependent()) { llvm::APSInt Value; if (ArraySize->isIntegerConstantExpr(Value, Context, 0, false)) { if (Value < llvm::APSInt( llvm::APInt::getNullValue(Value.getBitWidth()), false)) return ExprError(Diag(ArraySize->getSourceRange().getBegin(), diag::err_typecheck_negative_array_size) << ArraySize->getSourceRange()); } } } FunctionDecl *OperatorNew = 0; FunctionDecl *OperatorDelete = 0; Expr **PlaceArgs = (Expr**)PlacementArgs.get(); unsigned NumPlaceArgs = PlacementArgs.size(); if (!AllocType->isDependentType() && !Expr::hasAnyTypeDependentArguments(PlaceArgs, NumPlaceArgs) && FindAllocationFunctions(StartLoc, SourceRange(PlacementLParen, PlacementRParen), UseGlobal, AllocType, ArraySize, PlaceArgs, NumPlaceArgs, OperatorNew, OperatorDelete)) return ExprError(); bool Init = ConstructorLParen.isValid(); // --- Choosing a constructor --- // C++ 5.3.4p15 // 1) If T is a POD and there's no initializer (ConstructorLParen is invalid) // the object is not initialized. If the object, or any part of it, is // const-qualified, it's an error. // 2) If T is a POD and there's an empty initializer, the object is value- // initialized. // 3) If T is a POD and there's one initializer argument, the object is copy- // constructed. // 4) If T is a POD and there's more initializer arguments, it's an error. // 5) If T is not a POD, the initializer arguments are used as constructor // arguments. // // Or by the C++0x formulation: // 1) If there's no initializer, the object is default-initialized according // to C++0x rules. // 2) Otherwise, the object is direct-initialized. CXXConstructorDecl *Constructor = 0; Expr **ConsArgs = (Expr**)ConstructorArgs.get(); const RecordType *RT; unsigned NumConsArgs = ConstructorArgs.size(); if (AllocType->isDependentType()) { // Skip all the checks. } else if ((RT = AllocType->getAsRecordType()) && !AllocType->isAggregateType()) { Constructor = PerformInitializationByConstructor( AllocType, ConsArgs, NumConsArgs, D.getSourceRange().getBegin(), SourceRange(D.getSourceRange().getBegin(), ConstructorRParen), RT->getDecl()->getDeclName(), NumConsArgs != 0 ? IK_Direct : IK_Default); if (!Constructor) return ExprError(); } else { if (!Init) { // FIXME: Check that no subpart is const. if (AllocType.isConstQualified()) return ExprError(Diag(StartLoc, diag::err_new_uninitialized_const) << D.getSourceRange()); } else if (NumConsArgs == 0) { // Object is value-initialized. Do nothing. } else if (NumConsArgs == 1) { // Object is direct-initialized. // FIXME: What DeclarationName do we pass in here? if (CheckInitializerTypes(ConsArgs[0], AllocType, StartLoc, DeclarationName() /*AllocType.getAsString()*/, /*DirectInit=*/true)) return ExprError(); } else { return ExprError(Diag(StartLoc, diag::err_builtin_direct_init_more_than_one_arg) << SourceRange(ConstructorLParen, ConstructorRParen)); } } // FIXME: Also check that the destructor is accessible. (C++ 5.3.4p16) PlacementArgs.release(); ConstructorArgs.release(); return Owned(new (Context) CXXNewExpr(UseGlobal, OperatorNew, PlaceArgs, NumPlaceArgs, ParenTypeId, ArraySize, Constructor, Init, ConsArgs, NumConsArgs, OperatorDelete, ResultType, StartLoc, Init ? ConstructorRParen : SourceLocation())); } /// CheckAllocatedType - Checks that a type is suitable as the allocated type /// in a new-expression. /// dimension off and stores the size expression in ArraySize. bool Sema::CheckAllocatedType(QualType AllocType, const Declarator &D) { // C++ 5.3.4p1: "[The] type shall be a complete object type, but not an // abstract class type or array thereof. if (AllocType->isFunctionType()) return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type) << AllocType << 0 << D.getSourceRange(); else if (AllocType->isReferenceType()) return Diag(D.getSourceRange().getBegin(), diag::err_bad_new_type) << AllocType << 1 << D.getSourceRange(); else if (!AllocType->isDependentType() && RequireCompleteType(D.getSourceRange().getBegin(), AllocType, diag::err_new_incomplete_type, D.getSourceRange())) return true; else if (RequireNonAbstractType(D.getSourceRange().getBegin(), AllocType, diag::err_allocation_of_abstract_type)) return true; // Every dimension shall be of constant size. unsigned i = 1; while (const ArrayType *Array = Context.getAsArrayType(AllocType)) { if (!Array->isConstantArrayType()) { Diag(D.getTypeObject(i).Loc, diag::err_new_array_nonconst) << static_cast(D.getTypeObject(i).Arr.NumElts)->getSourceRange(); return true; } AllocType = Array->getElementType(); ++i; } return false; } /// FindAllocationFunctions - Finds the overloads of operator new and delete /// that are appropriate for the allocation. bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range, bool UseGlobal, QualType AllocType, bool IsArray, Expr **PlaceArgs, unsigned NumPlaceArgs, FunctionDecl *&OperatorNew, FunctionDecl *&OperatorDelete) { // --- Choosing an allocation function --- // C++ 5.3.4p8 - 14 & 18 // 1) If UseGlobal is true, only look in the global scope. Else, also look // in the scope of the allocated class. // 2) If an array size is given, look for operator new[], else look for // operator new. // 3) The first argument is always size_t. Append the arguments from the // placement form. // FIXME: Also find the appropriate delete operator. llvm::SmallVector AllocArgs(1 + NumPlaceArgs); // We don't care about the actual value of this argument. // FIXME: Should the Sema create the expression and embed it in the syntax // tree? Or should the consumer just recalculate the value? AllocArgs[0] = new (Context) IntegerLiteral(llvm::APInt::getNullValue( Context.Target.getPointerWidth(0)), Context.getSizeType(), SourceLocation()); std::copy(PlaceArgs, PlaceArgs + NumPlaceArgs, AllocArgs.begin() + 1); DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName( IsArray ? OO_Array_New : OO_New); if (AllocType->isRecordType() && !UseGlobal) { CXXRecordDecl *Record = cast(AllocType->getAsRecordType()->getDecl()); // FIXME: We fail to find inherited overloads. if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0], AllocArgs.size(), Record, /*AllowMissing=*/true, OperatorNew)) return true; } if (!OperatorNew) { // Didn't find a member overload. Look for a global one. DeclareGlobalNewDelete(); DeclContext *TUDecl = Context.getTranslationUnitDecl(); if (FindAllocationOverload(StartLoc, Range, NewName, &AllocArgs[0], AllocArgs.size(), TUDecl, /*AllowMissing=*/false, OperatorNew)) return true; } // FIXME: This is leaked on error. But so much is currently in Sema that it's // easier to clean it in one go. AllocArgs[0]->Destroy(Context); return false; } /// FindAllocationOverload - Find an fitting overload for the allocation /// function in the specified scope. bool Sema::FindAllocationOverload(SourceLocation StartLoc, SourceRange Range, DeclarationName Name, Expr** Args, unsigned NumArgs, DeclContext *Ctx, bool AllowMissing, FunctionDecl *&Operator) { DeclContext::lookup_iterator Alloc, AllocEnd; llvm::tie(Alloc, AllocEnd) = Ctx->lookup(Context, Name); if (Alloc == AllocEnd) { if (AllowMissing) return false; return Diag(StartLoc, diag::err_ovl_no_viable_function_in_call) << Name << Range; } OverloadCandidateSet Candidates; for (; Alloc != AllocEnd; ++Alloc) { // Even member operator new/delete are implicitly treated as // static, so don't use AddMemberCandidate. if (FunctionDecl *Fn = dyn_cast(*Alloc)) AddOverloadCandidate(Fn, Args, NumArgs, Candidates, /*SuppressUserConversions=*/false); } // Do the resolution. OverloadCandidateSet::iterator Best; switch(BestViableFunction(Candidates, Best)) { case OR_Success: { // Got one! FunctionDecl *FnDecl = Best->Function; // The first argument is size_t, and the first parameter must be size_t, // too. This is checked on declaration and can be assumed. (It can't be // asserted on, though, since invalid decls are left in there.) for (unsigned i = 1; i < NumArgs; ++i) { // FIXME: Passing word to diagnostic. if (PerformCopyInitialization(Args[i-1], FnDecl->getParamDecl(i)->getType(), "passing")) return true; } Operator = FnDecl; return false; } case OR_No_Viable_Function: Diag(StartLoc, diag::err_ovl_no_viable_function_in_call) << Name << Range; PrintOverloadCandidates(Candidates, /*OnlyViable=*/false); return true; case OR_Ambiguous: Diag(StartLoc, diag::err_ovl_ambiguous_call) << Name << Range; PrintOverloadCandidates(Candidates, /*OnlyViable=*/true); return true; case OR_Deleted: Diag(StartLoc, diag::err_ovl_deleted_call) << Best->Function->isDeleted() << Name << Range; PrintOverloadCandidates(Candidates, /*OnlyViable=*/true); return true; } assert(false && "Unreachable, bad result from BestViableFunction"); return true; } /// DeclareGlobalNewDelete - Declare the global forms of operator new and /// delete. These are: /// @code /// void* operator new(std::size_t) throw(std::bad_alloc); /// void* operator new[](std::size_t) throw(std::bad_alloc); /// void operator delete(void *) throw(); /// void operator delete[](void *) throw(); /// @endcode /// Note that the placement and nothrow forms of new are *not* implicitly /// declared. Their use requires including \. void Sema::DeclareGlobalNewDelete() { if (GlobalNewDeleteDeclared) return; GlobalNewDeleteDeclared = true; QualType VoidPtr = Context.getPointerType(Context.VoidTy); QualType SizeT = Context.getSizeType(); // FIXME: Exception specifications are not added. DeclareGlobalAllocationFunction( Context.DeclarationNames.getCXXOperatorName(OO_New), VoidPtr, SizeT); DeclareGlobalAllocationFunction( Context.DeclarationNames.getCXXOperatorName(OO_Array_New), VoidPtr, SizeT); DeclareGlobalAllocationFunction( Context.DeclarationNames.getCXXOperatorName(OO_Delete), Context.VoidTy, VoidPtr); DeclareGlobalAllocationFunction( Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete), Context.VoidTy, VoidPtr); } /// DeclareGlobalAllocationFunction - Declares a single implicit global /// allocation function if it doesn't already exist. void Sema::DeclareGlobalAllocationFunction(DeclarationName Name, QualType Return, QualType Argument) { DeclContext *GlobalCtx = Context.getTranslationUnitDecl(); // Check if this function is already declared. { DeclContext::lookup_iterator Alloc, AllocEnd; for (llvm::tie(Alloc, AllocEnd) = GlobalCtx->lookup(Context, Name); Alloc != AllocEnd; ++Alloc) { // FIXME: Do we need to check for default arguments here? FunctionDecl *Func = cast(*Alloc); if (Func->getNumParams() == 1 && Context.getCanonicalType(Func->getParamDecl(0)->getType())==Argument) return; } } QualType FnType = Context.getFunctionType(Return, &Argument, 1, false, 0); FunctionDecl *Alloc = FunctionDecl::Create(Context, GlobalCtx, SourceLocation(), Name, FnType, FunctionDecl::None, false, true, SourceLocation()); Alloc->setImplicit(); ParmVarDecl *Param = ParmVarDecl::Create(Context, Alloc, SourceLocation(), 0, Argument, VarDecl::None, 0); Alloc->setParams(Context, &Param, 1); // FIXME: Also add this declaration to the IdentifierResolver, but // make sure it is at the end of the chain to coincide with the // global scope. ((DeclContext *)TUScope->getEntity())->addDecl(Context, Alloc); } /// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in: /// @code ::delete ptr; @endcode /// or /// @code delete [] ptr; @endcode Action::OwningExprResult Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal, bool ArrayForm, ExprArg Operand) { // C++ 5.3.5p1: "The operand shall have a pointer type, or a class type // having a single conversion function to a pointer type. The result has // type void." // DR599 amends "pointer type" to "pointer to object type" in both cases. Expr *Ex = (Expr *)Operand.get(); if (!Ex->isTypeDependent()) { QualType Type = Ex->getType(); if (Type->isRecordType()) { // FIXME: Find that one conversion function and amend the type. } if (!Type->isPointerType()) return ExprError(Diag(StartLoc, diag::err_delete_operand) << Type << Ex->getSourceRange()); QualType Pointee = Type->getAsPointerType()->getPointeeType(); if (Pointee->isFunctionType() || Pointee->isVoidType()) return ExprError(Diag(StartLoc, diag::err_delete_operand) << Type << Ex->getSourceRange()); else if (!Pointee->isDependentType() && RequireCompleteType(StartLoc, Pointee, diag::warn_delete_incomplete, Ex->getSourceRange())) return ExprError(); // FIXME: Look up the correct operator delete overload and pass a pointer // along. // FIXME: Check access and ambiguity of operator delete and destructor. } Operand.release(); return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm, 0, Ex, StartLoc)); } /// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a /// C++ if/switch/while/for statement. /// e.g: "if (int x = f()) {...}" Action::OwningExprResult Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc, Declarator &D, SourceLocation EqualLoc, ExprArg AssignExprVal) { assert(AssignExprVal.get() && "Null assignment expression"); // C++ 6.4p2: // The declarator shall not specify a function or an array. // The type-specifier-seq shall not contain typedef and shall not declare a // new class or enumeration. assert(D.getDeclSpec().getStorageClassSpec() != DeclSpec::SCS_typedef && "Parser allowed 'typedef' as storage class of condition decl."); QualType Ty = GetTypeForDeclarator(D, S); if (Ty->isFunctionType()) { // The declarator shall not specify a function... // We exit without creating a CXXConditionDeclExpr because a FunctionDecl // would be created and CXXConditionDeclExpr wants a VarDecl. return ExprError(Diag(StartLoc, diag::err_invalid_use_of_function_type) << SourceRange(StartLoc, EqualLoc)); } else if (Ty->isArrayType()) { // ...or an array. Diag(StartLoc, diag::err_invalid_use_of_array_type) << SourceRange(StartLoc, EqualLoc); } else if (const RecordType *RT = Ty->getAsRecordType()) { RecordDecl *RD = RT->getDecl(); // The type-specifier-seq shall not declare a new class... if (RD->isDefinition() && (RD->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(RD)))) Diag(RD->getLocation(), diag::err_type_defined_in_condition); } else if (const EnumType *ET = Ty->getAsEnumType()) { EnumDecl *ED = ET->getDecl(); // ...or enumeration. if (ED->isDefinition() && (ED->getIdentifier() == 0 || S->isDeclScope(DeclPtrTy::make(ED)))) Diag(ED->getLocation(), diag::err_type_defined_in_condition); } DeclPtrTy Dcl = ActOnDeclarator(S, D, DeclPtrTy()); if (!Dcl) return ExprError(); AddInitializerToDecl(Dcl, move(AssignExprVal)); // Mark this variable as one that is declared within a conditional. // We know that the decl had to be a VarDecl because that is the only type of // decl that can be assigned and the grammar requires an '='. VarDecl *VD = cast(Dcl.getAs()); VD->setDeclaredInCondition(true); return Owned(new (Context) CXXConditionDeclExpr(StartLoc, EqualLoc, VD)); } /// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid. bool Sema::CheckCXXBooleanCondition(Expr *&CondExpr) { // C++ 6.4p4: // The value of a condition that is an initialized declaration in a statement // other than a switch statement is the value of the declared variable // implicitly converted to type bool. If that conversion is ill-formed, the // program is ill-formed. // The value of a condition that is an expression is the value of the // expression, implicitly converted to bool. // return PerformContextuallyConvertToBool(CondExpr); } /// Helper function to determine whether this is the (deprecated) C++ /// conversion from a string literal to a pointer to non-const char or /// non-const wchar_t (for narrow and wide string literals, /// respectively). bool Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) { // Look inside the implicit cast, if it exists. if (ImplicitCastExpr *Cast = dyn_cast(From)) From = Cast->getSubExpr(); // A string literal (2.13.4) that is not a wide string literal can // be converted to an rvalue of type "pointer to char"; a wide // string literal can be converted to an rvalue of type "pointer // to wchar_t" (C++ 4.2p2). if (StringLiteral *StrLit = dyn_cast(From)) if (const PointerType *ToPtrType = ToType->getAsPointerType()) if (const BuiltinType *ToPointeeType = ToPtrType->getPointeeType()->getAsBuiltinType()) { // This conversion is considered only when there is an // explicit appropriate pointer target type (C++ 4.2p2). if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 && ((StrLit->isWide() && ToPointeeType->isWideCharType()) || (!StrLit->isWide() && (ToPointeeType->getKind() == BuiltinType::Char_U || ToPointeeType->getKind() == BuiltinType::Char_S)))) return true; } return false; } /// PerformImplicitConversion - Perform an implicit conversion of the /// expression From to the type ToType. Returns true if there was an /// error, false otherwise. The expression From is replaced with the /// converted expression. Flavor is the kind of conversion we're /// performing, used in the error message. If @p AllowExplicit, /// explicit user-defined conversions are permitted. @p Elidable should be true /// when called for copies which may be elided (C++ 12.8p15). C++0x overload /// resolution works differently in that case. bool Sema::PerformImplicitConversion(Expr *&From, QualType ToType, const char *Flavor, bool AllowExplicit, bool Elidable) { ImplicitConversionSequence ICS; ICS.ConversionKind = ImplicitConversionSequence::BadConversion; if (Elidable && getLangOptions().CPlusPlus0x) { ICS = TryImplicitConversion(From, ToType, /*SuppressUserConversions*/false, AllowExplicit, /*ForceRValue*/true); } if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) { ICS = TryImplicitConversion(From, ToType, false, AllowExplicit); } return PerformImplicitConversion(From, ToType, ICS, Flavor); } /// PerformImplicitConversion - Perform an implicit conversion of the /// expression From to the type ToType using the pre-computed implicit /// conversion sequence ICS. Returns true if there was an error, false /// otherwise. The expression From is replaced with the converted /// expression. Flavor is the kind of conversion we're performing, /// used in the error message. bool Sema::PerformImplicitConversion(Expr *&From, QualType ToType, const ImplicitConversionSequence &ICS, const char* Flavor) { switch (ICS.ConversionKind) { case ImplicitConversionSequence::StandardConversion: if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor)) return true; break; case ImplicitConversionSequence::UserDefinedConversion: // FIXME: This is, of course, wrong. We'll need to actually call // the constructor or conversion operator, and then cope with the // standard conversions. ImpCastExprToType(From, ToType.getNonReferenceType(), ToType->isLValueReferenceType()); return false; case ImplicitConversionSequence::EllipsisConversion: assert(false && "Cannot perform an ellipsis conversion"); return false; case ImplicitConversionSequence::BadConversion: return true; } // Everything went well. return false; } /// PerformImplicitConversion - Perform an implicit conversion of the /// expression From to the type ToType by following the standard /// conversion sequence SCS. Returns true if there was an error, false /// otherwise. The expression From is replaced with the converted /// expression. Flavor is the context in which we're performing this /// conversion, for use in error messages. bool Sema::PerformImplicitConversion(Expr *&From, QualType ToType, const StandardConversionSequence& SCS, const char *Flavor) { // Overall FIXME: we are recomputing too many types here and doing // far too much extra work. What this means is that we need to keep // track of more information that is computed when we try the // implicit conversion initially, so that we don't need to recompute // anything here. QualType FromType = From->getType(); if (SCS.CopyConstructor) { // FIXME: Create a temporary object by calling the copy // constructor. ImpCastExprToType(From, ToType.getNonReferenceType(), ToType->isLValueReferenceType()); return false; } // Perform the first implicit conversion. switch (SCS.First) { case ICK_Identity: case ICK_Lvalue_To_Rvalue: // Nothing to do. break; case ICK_Array_To_Pointer: FromType = Context.getArrayDecayedType(FromType); ImpCastExprToType(From, FromType); break; case ICK_Function_To_Pointer: if (Context.getCanonicalType(FromType) == Context.OverloadTy) { FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true); if (!Fn) return true; if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin())) return true; FixOverloadedFunctionReference(From, Fn); FromType = From->getType(); } FromType = Context.getPointerType(FromType); ImpCastExprToType(From, FromType); break; default: assert(false && "Improper first standard conversion"); break; } // Perform the second implicit conversion switch (SCS.Second) { case ICK_Identity: // Nothing to do. break; case ICK_Integral_Promotion: case ICK_Floating_Promotion: case ICK_Complex_Promotion: case ICK_Integral_Conversion: case ICK_Floating_Conversion: case ICK_Complex_Conversion: case ICK_Floating_Integral: case ICK_Complex_Real: case ICK_Compatible_Conversion: // FIXME: Go deeper to get the unqualified type! FromType = ToType.getUnqualifiedType(); ImpCastExprToType(From, FromType); break; case ICK_Pointer_Conversion: if (SCS.IncompatibleObjC) { // Diagnose incompatible Objective-C conversions Diag(From->getSourceRange().getBegin(), diag::ext_typecheck_convert_incompatible_pointer) << From->getType() << ToType << Flavor << From->getSourceRange(); } if (CheckPointerConversion(From, ToType)) return true; ImpCastExprToType(From, ToType); break; case ICK_Pointer_Member: if (CheckMemberPointerConversion(From, ToType)) return true; ImpCastExprToType(From, ToType); break; case ICK_Boolean_Conversion: FromType = Context.BoolTy; ImpCastExprToType(From, FromType); break; default: assert(false && "Improper second standard conversion"); break; } switch (SCS.Third) { case ICK_Identity: // Nothing to do. break; case ICK_Qualification: // FIXME: Not sure about lvalue vs rvalue here in the presence of // rvalue references. ImpCastExprToType(From, ToType.getNonReferenceType(), ToType->isLValueReferenceType()); break; default: assert(false && "Improper second standard conversion"); break; } return false; } Sema::OwningExprResult Sema::ActOnUnaryTypeTrait(UnaryTypeTrait OTT, SourceLocation KWLoc, SourceLocation LParen, TypeTy *Ty, SourceLocation RParen) { // FIXME: Some of the type traits have requirements. Interestingly, only the // __is_base_of requirement is explicitly stated to be diagnosed. Indeed, // G++ accepts __is_pod(Incomplete) without complaints, and claims that the // type is indeed a POD. // There is no point in eagerly computing the value. The traits are designed // to be used from type trait templates, so Ty will be a template parameter // 99% of the time. return Owned(new (Context) UnaryTypeTraitExpr(KWLoc, OTT, QualType::getFromOpaquePtr(Ty), RParen, Context.BoolTy)); } QualType Sema::CheckPointerToMemberOperands( Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect) { const char *OpSpelling = isIndirect ? "->*" : ".*"; // C++ 5.5p2 // The binary operator .* [p3: ->*] binds its second operand, which shall // be of type "pointer to member of T" (where T is a completely-defined // class type) [...] QualType RType = rex->getType(); const MemberPointerType *MemPtr = RType->getAsMemberPointerType(); if (!MemPtr) { Diag(Loc, diag::err_bad_memptr_rhs) << OpSpelling << RType << rex->getSourceRange(); return QualType(); } QualType Class(MemPtr->getClass(), 0); // C++ 5.5p2 // [...] to its first operand, which shall be of class T or of a class of // which T is an unambiguous and accessible base class. [p3: a pointer to // such a class] QualType LType = lex->getType(); if (isIndirect) { if (const PointerType *Ptr = LType->getAsPointerType()) LType = Ptr->getPointeeType().getNonReferenceType(); else { Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling << 1 << LType << lex->getSourceRange(); return QualType(); } } if (Context.getCanonicalType(Class).getUnqualifiedType() != Context.getCanonicalType(LType).getUnqualifiedType()) { BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, /*DetectVirtual=*/false); // FIXME: Would it be useful to print full ambiguity paths, // or is that overkill? if (!IsDerivedFrom(LType, Class, Paths) || Paths.isAmbiguous(Context.getCanonicalType(Class))) { Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling << (int)isIndirect << lex->getType() << lex->getSourceRange(); return QualType(); } } // C++ 5.5p2 // The result is an object or a function of the type specified by the // second operand. // The cv qualifiers are the union of those in the pointer and the left side, // in accordance with 5.5p5 and 5.2.5. // FIXME: This returns a dereferenced member function pointer as a normal // function type. However, the only operation valid on such functions is // calling them. There's also a GCC extension to get a function pointer to // the thing, which is another complication, because this type - unlike the // type that is the result of this expression - takes the class as the first // argument. // We probably need a "MemberFunctionClosureType" or something like that. QualType Result = MemPtr->getPointeeType(); if (LType.isConstQualified()) Result.addConst(); if (LType.isVolatileQualified()) Result.addVolatile(); return Result; } /// \brief Get the target type of a standard or user-defined conversion. static QualType TargetType(const ImplicitConversionSequence &ICS) { assert((ICS.ConversionKind == ImplicitConversionSequence::StandardConversion || ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion) && "function only valid for standard or user-defined conversions"); if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion) return QualType::getFromOpaquePtr(ICS.Standard.ToTypePtr); return QualType::getFromOpaquePtr(ICS.UserDefined.After.ToTypePtr); } /// \brief Try to convert a type to another according to C++0x 5.16p3. /// /// This is part of the parameter validation for the ? operator. If either /// value operand is a class type, the two operands are attempted to be /// converted to each other. This function does the conversion in one direction. /// It emits a diagnostic and returns true only if it finds an ambiguous /// conversion. static bool TryClassUnification(Sema &Self, Expr *From, Expr *To, SourceLocation QuestionLoc, ImplicitConversionSequence &ICS) { // C++0x 5.16p3 // The process for determining whether an operand expression E1 of type T1 // can be converted to match an operand expression E2 of type T2 is defined // as follows: // -- If E2 is an lvalue: if (To->isLvalue(Self.Context) == Expr::LV_Valid) { // E1 can be converted to match E2 if E1 can be implicitly converted to // type "lvalue reference to T2", subject to the constraint that in the // conversion the reference must bind directly to E1. if (!Self.CheckReferenceInit(From, Self.Context.getLValueReferenceType(To->getType()), &ICS)) { assert((ICS.ConversionKind == ImplicitConversionSequence::StandardConversion || ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion) && "expected a definite conversion"); bool DirectBinding = ICS.ConversionKind == ImplicitConversionSequence::StandardConversion ? ICS.Standard.DirectBinding : ICS.UserDefined.After.DirectBinding; if (DirectBinding) return false; } } ICS.ConversionKind = ImplicitConversionSequence::BadConversion; // -- If E2 is an rvalue, or if the conversion above cannot be done: // -- if E1 and E2 have class type, and the underlying class types are // the same or one is a base class of the other: QualType FTy = From->getType(); QualType TTy = To->getType(); const RecordType *FRec = FTy->getAsRecordType(); const RecordType *TRec = TTy->getAsRecordType(); bool FDerivedFromT = FRec && TRec && Self.IsDerivedFrom(FTy, TTy); if (FRec && TRec && (FRec == TRec || FDerivedFromT || Self.IsDerivedFrom(TTy, FTy))) { // E1 can be converted to match E2 if the class of T2 is the // same type as, or a base class of, the class of T1, and // [cv2 > cv1]. if ((FRec == TRec || FDerivedFromT) && TTy.isAtLeastAsQualifiedAs(FTy)) { // Could still fail if there's no copy constructor. // FIXME: Is this a hard error then, or just a conversion failure? The // standard doesn't say. ICS = Self.TryCopyInitialization(From, TTy); } } else { // -- Otherwise: E1 can be converted to match E2 if E1 can be // implicitly converted to the type that expression E2 would have // if E2 were converted to an rvalue. // First find the decayed type. if (TTy->isFunctionType()) TTy = Self.Context.getPointerType(TTy); else if(TTy->isArrayType()) TTy = Self.Context.getArrayDecayedType(TTy); // Now try the implicit conversion. // FIXME: This doesn't detect ambiguities. ICS = Self.TryImplicitConversion(From, TTy); } return false; } /// \brief Try to find a common type for two according to C++0x 5.16p5. /// /// This is part of the parameter validation for the ? operator. If either /// value operand is a class type, overload resolution is used to find a /// conversion to a common type. static bool FindConditionalOverload(Sema &Self, Expr *&LHS, Expr *&RHS, SourceLocation Loc) { Expr *Args[2] = { LHS, RHS }; OverloadCandidateSet CandidateSet; Self.AddBuiltinOperatorCandidates(OO_Conditional, Args, 2, CandidateSet); OverloadCandidateSet::iterator Best; switch (Self.BestViableFunction(CandidateSet, Best)) { case Sema::OR_Success: // We found a match. Perform the conversions on the arguments and move on. if (Self.PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0], Best->Conversions[0], "converting") || Self.PerformImplicitConversion(RHS, Best->BuiltinTypes.ParamTypes[1], Best->Conversions[1], "converting")) break; return false; case Sema::OR_No_Viable_Function: Self.Diag(Loc, diag::err_typecheck_cond_incompatible_operands) << LHS->getType() << RHS->getType() << LHS->getSourceRange() << RHS->getSourceRange(); return true; case Sema::OR_Ambiguous: Self.Diag(Loc, diag::err_conditional_ambiguous_ovl) << LHS->getType() << RHS->getType() << LHS->getSourceRange() << RHS->getSourceRange(); // FIXME: Print the possible common types by printing the return types // of the viable candidates. break; case Sema::OR_Deleted: assert(false && "Conditional operator has only built-in overloads"); break; } return true; } /// \brief Perform an "extended" implicit conversion as returned by /// TryClassUnification. /// /// TryClassUnification generates ICSs that include reference bindings. /// PerformImplicitConversion is not suitable for this; it chokes if the /// second part of a standard conversion is ICK_DerivedToBase. This function /// handles the reference binding specially. static bool ConvertForConditional(Sema &Self, Expr *&E, const ImplicitConversionSequence &ICS) { if (ICS.ConversionKind == ImplicitConversionSequence::StandardConversion && ICS.Standard.ReferenceBinding) { assert(ICS.Standard.DirectBinding && "TryClassUnification should never generate indirect ref bindings"); // FIXME: CheckReferenceInit should be able to reuse the ICS instead of // redoing all the work. return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType( TargetType(ICS))); } if (ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion && ICS.UserDefined.After.ReferenceBinding) { assert(ICS.UserDefined.After.DirectBinding && "TryClassUnification should never generate indirect ref bindings"); return Self.CheckReferenceInit(E, Self.Context.getLValueReferenceType( TargetType(ICS))); } if (Self.PerformImplicitConversion(E, TargetType(ICS), ICS, "converting")) return true; return false; } /// \brief Check the operands of ?: under C++ semantics. /// /// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y /// extension. In this case, LHS == Cond. (But they're not aliases.) QualType Sema::CXXCheckConditionalOperands(Expr *&Cond, Expr *&LHS, Expr *&RHS, SourceLocation QuestionLoc) { // FIXME: Handle C99's complex types, vector types, block pointers and // Obj-C++ interface pointers. // C++0x 5.16p1 // The first expression is contextually converted to bool. if (!Cond->isTypeDependent()) { if (CheckCXXBooleanCondition(Cond)) return QualType(); } // Either of the arguments dependent? if (LHS->isTypeDependent() || RHS->isTypeDependent()) return Context.DependentTy; // C++0x 5.16p2 // If either the second or the third operand has type (cv) void, ... QualType LTy = LHS->getType(); QualType RTy = RHS->getType(); bool LVoid = LTy->isVoidType(); bool RVoid = RTy->isVoidType(); if (LVoid || RVoid) { // ... then the [l2r] conversions are performed on the second and third // operands ... DefaultFunctionArrayConversion(LHS); DefaultFunctionArrayConversion(RHS); LTy = LHS->getType(); RTy = RHS->getType(); // ... and one of the following shall hold: // -- The second or the third operand (but not both) is a throw- // expression; the result is of the type of the other and is an rvalue. bool LThrow = isa(LHS); bool RThrow = isa(RHS); if (LThrow && !RThrow) return RTy; if (RThrow && !LThrow) return LTy; // -- Both the second and third operands have type void; the result is of // type void and is an rvalue. if (LVoid && RVoid) return Context.VoidTy; // Neither holds, error. Diag(QuestionLoc, diag::err_conditional_void_nonvoid) << (LVoid ? RTy : LTy) << (LVoid ? 0 : 1) << LHS->getSourceRange() << RHS->getSourceRange(); return QualType(); } // Neither is void. // C++0x 5.16p3 // Otherwise, if the second and third operand have different types, and // either has (cv) class type, and attempt is made to convert each of those // operands to the other. if (Context.getCanonicalType(LTy) != Context.getCanonicalType(RTy) && (LTy->isRecordType() || RTy->isRecordType())) { ImplicitConversionSequence ICSLeftToRight, ICSRightToLeft; // These return true if a single direction is already ambiguous. if (TryClassUnification(*this, LHS, RHS, QuestionLoc, ICSLeftToRight)) return QualType(); if (TryClassUnification(*this, RHS, LHS, QuestionLoc, ICSRightToLeft)) return QualType(); bool HaveL2R = ICSLeftToRight.ConversionKind != ImplicitConversionSequence::BadConversion; bool HaveR2L = ICSRightToLeft.ConversionKind != ImplicitConversionSequence::BadConversion; // If both can be converted, [...] the program is ill-formed. if (HaveL2R && HaveR2L) { Diag(QuestionLoc, diag::err_conditional_ambiguous) << LTy << RTy << LHS->getSourceRange() << RHS->getSourceRange(); return QualType(); } // If exactly one conversion is possible, that conversion is applied to // the chosen operand and the converted operands are used in place of the // original operands for the remainder of this section. if (HaveL2R) { if (ConvertForConditional(*this, LHS, ICSLeftToRight)) return QualType(); LTy = LHS->getType(); } else if (HaveR2L) { if (ConvertForConditional(*this, RHS, ICSRightToLeft)) return QualType(); RTy = RHS->getType(); } } // C++0x 5.16p4 // If the second and third operands are lvalues and have the same type, // the result is of that type [...] bool Same = Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy); if (Same && LHS->isLvalue(Context) == Expr::LV_Valid && RHS->isLvalue(Context) == Expr::LV_Valid) return LTy; // C++0x 5.16p5 // Otherwise, the result is an rvalue. If the second and third operands // do not have the same type, and either has (cv) class type, ... if (!Same && (LTy->isRecordType() || RTy->isRecordType())) { // ... overload resolution is used to determine the conversions (if any) // to be applied to the operands. If the overload resolution fails, the // program is ill-formed. if (FindConditionalOverload(*this, LHS, RHS, QuestionLoc)) return QualType(); } // C++0x 5.16p6 // LValue-to-rvalue, array-to-pointer, and function-to-pointer standard // conversions are performed on the second and third operands. DefaultFunctionArrayConversion(LHS); DefaultFunctionArrayConversion(RHS); LTy = LHS->getType(); RTy = RHS->getType(); // After those conversions, one of the following shall hold: // -- The second and third operands have the same type; the result // is of that type. if (Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy)) return LTy; // -- The second and third operands have arithmetic or enumeration type; // the usual arithmetic conversions are performed to bring them to a // common type, and the result is of that type. if (LTy->isArithmeticType() && RTy->isArithmeticType()) { UsualArithmeticConversions(LHS, RHS); return LHS->getType(); } // -- The second and third operands have pointer type, or one has pointer // type and the other is a null pointer constant; pointer conversions // and qualification conversions are performed to bring them to their // composite pointer type. The result is of the composite pointer type. QualType Composite = FindCompositePointerType(LHS, RHS); if (!Composite.isNull()) return Composite; // Fourth bullet is same for pointers-to-member. However, the possible // conversions are far more limited: we have null-to-pointer, upcast of // containing class, and second-level cv-ness. // cv-ness is not a union, but must match one of the two operands. (Which, // frankly, is stupid.) const MemberPointerType *LMemPtr = LTy->getAsMemberPointerType(); const MemberPointerType *RMemPtr = RTy->getAsMemberPointerType(); if (LMemPtr && RHS->isNullPointerConstant(Context)) { ImpCastExprToType(RHS, LTy); return LTy; } if (RMemPtr && LHS->isNullPointerConstant(Context)) { ImpCastExprToType(LHS, RTy); return RTy; } if (LMemPtr && RMemPtr) { QualType LPointee = LMemPtr->getPointeeType(); QualType RPointee = RMemPtr->getPointeeType(); // First, we check that the unqualified pointee type is the same. If it's // not, there's no conversion that will unify the two pointers. if (Context.getCanonicalType(LPointee).getUnqualifiedType() == Context.getCanonicalType(RPointee).getUnqualifiedType()) { // Second, we take the greater of the two cv qualifications. If neither // is greater than the other, the conversion is not possible. unsigned Q = LPointee.getCVRQualifiers() | RPointee.getCVRQualifiers(); if (Q == LPointee.getCVRQualifiers() || Q == RPointee.getCVRQualifiers()){ // Third, we check if either of the container classes is derived from // the other. QualType LContainer(LMemPtr->getClass(), 0); QualType RContainer(RMemPtr->getClass(), 0); QualType MoreDerived; if (Context.getCanonicalType(LContainer) == Context.getCanonicalType(RContainer)) MoreDerived = LContainer; else if (IsDerivedFrom(LContainer, RContainer)) MoreDerived = LContainer; else if (IsDerivedFrom(RContainer, LContainer)) MoreDerived = RContainer; if (!MoreDerived.isNull()) { // The type 'Q Pointee (MoreDerived::*)' is the common type. // We don't use ImpCastExprToType here because this could still fail // for ambiguous or inaccessible conversions. QualType Common = Context.getMemberPointerType( LPointee.getQualifiedType(Q), MoreDerived.getTypePtr()); if (PerformImplicitConversion(LHS, Common, "converting")) return QualType(); if (PerformImplicitConversion(RHS, Common, "converting")) return QualType(); return Common; } } } } Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands) << LHS->getType() << RHS->getType() << LHS->getSourceRange() << RHS->getSourceRange(); return QualType(); } /// \brief Find a merged pointer type and convert the two expressions to it. /// /// This finds the composite pointer type for @p E1 and @p E2 according to /// C++0x 5.9p2. It converts both expressions to this type and returns it. /// It does not emit diagnostics. QualType Sema::FindCompositePointerType(Expr *&E1, Expr *&E2) { assert(getLangOptions().CPlusPlus && "This function assumes C++"); QualType T1 = E1->getType(), T2 = E2->getType(); if(!T1->isPointerType() && !T2->isPointerType()) return QualType(); // C++0x 5.9p2 // Pointer conversions and qualification conversions are performed on // pointer operands to bring them to their composite pointer type. If // one operand is a null pointer constant, the composite pointer type is // the type of the other operand. if (E1->isNullPointerConstant(Context)) { ImpCastExprToType(E1, T2); return T2; } if (E2->isNullPointerConstant(Context)) { ImpCastExprToType(E2, T1); return T1; } // Now both have to be pointers. if(!T1->isPointerType() || !T2->isPointerType()) return QualType(); // Otherwise, of one of the operands has type "pointer to cv1 void," then // the other has type "pointer to cv2 T" and the composite pointer type is // "pointer to cv12 void," where cv12 is the union of cv1 and cv2. // Otherwise, the composite pointer type is a pointer type similar to the // type of one of the operands, with a cv-qualification signature that is // the union of the cv-qualification signatures of the operand types. // In practice, the first part here is redundant; it's subsumed by the second. // What we do here is, we build the two possible composite types, and try the // conversions in both directions. If only one works, or if the two composite // types are the same, we have succeeded. llvm::SmallVector QualifierUnion; QualType Composite1 = T1, Composite2 = T2; const PointerType *Ptr1, *Ptr2; while ((Ptr1 = Composite1->getAsPointerType()) && (Ptr2 = Composite2->getAsPointerType())) { Composite1 = Ptr1->getPointeeType(); Composite2 = Ptr2->getPointeeType(); QualifierUnion.push_back( Composite1.getCVRQualifiers() | Composite2.getCVRQualifiers()); } // Rewrap the composites as pointers with the union CVRs. for (llvm::SmallVector::iterator I = QualifierUnion.begin(), E = QualifierUnion.end(); I != E; ++I) { Composite1 = Context.getPointerType(Composite1.getQualifiedType(*I)); Composite2 = Context.getPointerType(Composite2.getQualifiedType(*I)); } ImplicitConversionSequence E1ToC1 = TryImplicitConversion(E1, Composite1); ImplicitConversionSequence E2ToC1 = TryImplicitConversion(E2, Composite1); ImplicitConversionSequence E1ToC2, E2ToC2; E1ToC2.ConversionKind = ImplicitConversionSequence::BadConversion; E2ToC2.ConversionKind = ImplicitConversionSequence::BadConversion; if (Context.getCanonicalType(Composite1) != Context.getCanonicalType(Composite2)) { E1ToC2 = TryImplicitConversion(E1, Composite2); E2ToC2 = TryImplicitConversion(E2, Composite2); } bool ToC1Viable = E1ToC1.ConversionKind != ImplicitConversionSequence::BadConversion && E2ToC1.ConversionKind != ImplicitConversionSequence::BadConversion; bool ToC2Viable = E1ToC2.ConversionKind != ImplicitConversionSequence::BadConversion && E2ToC2.ConversionKind != ImplicitConversionSequence::BadConversion; if (ToC1Viable && !ToC2Viable) { if (!PerformImplicitConversion(E1, Composite1, E1ToC1, "converting") && !PerformImplicitConversion(E2, Composite1, E2ToC1, "converting")) return Composite1; } if (ToC2Viable && !ToC1Viable) { if (!PerformImplicitConversion(E1, Composite2, E1ToC2, "converting") && !PerformImplicitConversion(E2, Composite2, E2ToC2, "converting")) return Composite2; } return QualType(); }