| //===--- 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 "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/Diagnostic.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::ExprResult |
| Sema::ActOnCXXConversionFunctionExpr(Scope *S, SourceLocation OperatorLoc, |
| TypeTy *Ty, bool HasTrailingLParen, |
| const CXXScopeSpec &SS) { |
| QualType ConvType = QualType::getFromOpaquePtr(Ty); |
| QualType ConvTypeCanon = Context.getCanonicalType(ConvType); |
| DeclarationName ConvName |
| = Context.DeclarationNames.getCXXConversionFunctionName(ConvTypeCanon); |
| return ActOnDeclarationNameExpr(S, OperatorLoc, ConvName, HasTrailingLParen, |
| &SS); |
| } |
| |
| /// 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::ExprResult |
| Sema::ActOnCXXOperatorFunctionIdExpr(Scope *S, SourceLocation OperatorLoc, |
| OverloadedOperatorKind Op, |
| bool HasTrailingLParen, |
| const CXXScopeSpec &SS) { |
| DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(Op); |
| return ActOnDeclarationNameExpr(S, OperatorLoc, Name, HasTrailingLParen, &SS); |
| } |
| |
| /// ActOnCXXTypeidOfType - Parse typeid( type-id ). |
| Action::ExprResult |
| Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc, |
| bool isType, void *TyOrExpr, SourceLocation RParenLoc) { |
| const NamespaceDecl *StdNs = GetStdNamespace(); |
| if (!StdNs) |
| return Diag(OpLoc, diag::err_need_header_before_typeid); |
| |
| IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info"); |
| Decl *TypeInfoDecl = LookupDecl(TypeInfoII, |
| Decl::IDNS_Tag | Decl::IDNS_Ordinary, |
| 0, StdNs, /*createBuiltins=*/false); |
| RecordDecl *TypeInfoRecordDecl = dyn_cast_or_null<RecordDecl>(TypeInfoDecl); |
| if (!TypeInfoRecordDecl) |
| return Diag(OpLoc, diag::err_need_header_before_typeid); |
| |
| QualType TypeInfoType = Context.getTypeDeclType(TypeInfoRecordDecl); |
| |
| return new CXXTypeidExpr(isType, TyOrExpr, TypeInfoType.withConst(), |
| SourceRange(OpLoc, RParenLoc)); |
| } |
| |
| /// ActOnCXXBoolLiteral - Parse {true,false} literals. |
| Action::ExprResult |
| Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) { |
| assert((Kind == tok::kw_true || Kind == tok::kw_false) && |
| "Unknown C++ Boolean value!"); |
| return new CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc); |
| } |
| |
| /// ActOnCXXThrow - Parse throw expressions. |
| Action::ExprResult |
| Sema::ActOnCXXThrow(SourceLocation OpLoc, ExprTy *E) { |
| return new CXXThrowExpr((Expr*)E, Context.VoidTy, OpLoc); |
| } |
| |
| Action::ExprResult 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<FunctionDecl>(CurContext)) { |
| Diag(ThisLoc, diag::err_invalid_this_use); |
| return ExprResult(true); |
| } |
| |
| if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext)) |
| if (MD->isInstance()) |
| return new CXXThisExpr(ThisLoc, MD->getThisType(Context)); |
| |
| return 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::ExprResult |
| Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep, |
| SourceLocation LParenLoc, |
| ExprTy **ExprTys, unsigned NumExprs, |
| SourceLocation *CommaLocs, |
| SourceLocation RParenLoc) { |
| assert(TypeRep && "Missing type!"); |
| QualType Ty = QualType::getFromOpaquePtr(TypeRep); |
| Expr **Exprs = (Expr**)ExprTys; |
| SourceLocation TyBeginLoc = TypeRange.getBegin(); |
| SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc); |
| |
| if (const RecordType *RT = Ty->getAsRecordType()) { |
| // C++ 5.2.3p1: |
| // If the simple-type-specifier specifies a class type, the class type shall |
| // be complete. |
| // |
| if (!RT->getDecl()->isDefinition()) |
| return Diag(TyBeginLoc, diag::err_invalid_incomplete_type_use, |
| Ty.getAsString(), FullRange); |
| |
| unsigned DiagID = PP.getDiagnostics().getCustomDiagID(Diagnostic::Error, |
| "class constructors are not supported yet"); |
| return Diag(TyBeginLoc, DiagID); |
| } |
| |
| // C++ 5.2.3p1: |
| // 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 true; |
| return new CXXFunctionalCastExpr(Ty.getNonReferenceType(), Ty, TyBeginLoc, |
| Exprs[0], RParenLoc); |
| } |
| |
| // C++ 5.2.3p1: |
| // 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 Diag(CommaLocs[0], diag::err_builtin_func_cast_more_than_one_arg) |
| << FullRange; |
| |
| assert(NumExprs == 0 && "Expected 0 expressions"); |
| |
| // C++ 5.2.3p2: |
| // 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 Diag(TyBeginLoc, diag::err_value_init_for_array_type) << FullRange; |
| if (Ty->isIncompleteType() && !Ty->isVoidType()) |
| return Diag(TyBeginLoc, diag::err_invalid_incomplete_type_use) |
| << Ty.getAsString() << FullRange; |
| |
| return new CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc); |
| } |
| |
| |
| /// ActOnCXXConditionDeclarationExpr - Parsed a condition declaration of a |
| /// C++ if/switch/while/for statement. |
| /// e.g: "if (int x = f()) {...}" |
| Action::ExprResult |
| Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc, |
| Declarator &D, |
| SourceLocation EqualLoc, |
| ExprTy *AssignExprVal) { |
| assert(AssignExprVal && "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 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(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(ED))) |
| Diag(ED->getLocation(), diag::err_type_defined_in_condition); |
| } |
| |
| DeclTy *Dcl = ActOnDeclarator(S, D, 0); |
| if (!Dcl) |
| return true; |
| AddInitializerToDecl(Dcl, AssignExprVal); |
| |
| return new CXXConditionDeclExpr(StartLoc, EqualLoc, |
| cast<VarDecl>(static_cast<Decl *>(Dcl))); |
| } |
| |
| /// 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. |
| // |
| QualType Ty = CondExpr->getType(); // Save the type. |
| AssignConvertType |
| ConvTy = CheckSingleAssignmentConstraints(Context.BoolTy, CondExpr); |
| if (ConvTy == Incompatible) |
| return Diag(CondExpr->getLocStart(), diag::err_typecheck_bool_condition, |
| Ty.getAsString(), CondExpr->getSourceRange()); |
| return false; |
| } |
| |
| /// 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<ImplicitCastExpr>(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<StringLiteral>(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. |
| bool |
| Sema::PerformImplicitConversion(Expr *&From, QualType ToType) |
| { |
| ImplicitConversionSequence ICS = TryImplicitConversion(From, ToType); |
| switch (ICS.ConversionKind) { |
| case ImplicitConversionSequence::StandardConversion: |
| if (PerformImplicitConversion(From, ToType, ICS.Standard)) |
| 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); |
| 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. |
| bool |
| Sema::PerformImplicitConversion(Expr *&From, QualType ToType, |
| const StandardConversionSequence& SCS) |
| { |
| // 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); |
| 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: |
| if (FromType->isOverloadType()) { |
| FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true); |
| if (!Fn) |
| return true; |
| |
| FixOverloadedFunctionReference(From, Fn); |
| FromType = From->getType(); |
| } else { |
| FromType = Context.getArrayDecayedType(FromType); |
| } |
| ImpCastExprToType(From, FromType); |
| break; |
| |
| case ICK_Function_To_Pointer: |
| 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_Integral_Conversion: |
| case ICK_Floating_Conversion: |
| case ICK_Floating_Integral: |
| FromType = ToType.getUnqualifiedType(); |
| ImpCastExprToType(From, FromType); |
| break; |
| |
| case ICK_Pointer_Conversion: |
| if (CheckPointerConversion(From, ToType)) |
| return true; |
| ImpCastExprToType(From, ToType); |
| break; |
| |
| case ICK_Pointer_Member: |
| // FIXME: Implement pointer-to-member conversions. |
| assert(false && "Pointer-to-member conversions are unsupported"); |
| 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: |
| ImpCastExprToType(From, ToType); |
| break; |
| |
| default: |
| assert(false && "Improper second standard conversion"); |
| break; |
| } |
| |
| return false; |
| } |
| |