diff options
Diffstat (limited to 'lib/Sema/SemaInit.h')
| -rw-r--r-- | lib/Sema/SemaInit.h | 579 |
1 files changed, 579 insertions, 0 deletions
diff --git a/lib/Sema/SemaInit.h b/lib/Sema/SemaInit.h new file mode 100644 index 0000000000000..2d4b01f26b0de --- /dev/null +++ b/lib/Sema/SemaInit.h @@ -0,0 +1,579 @@ +//===--- SemaInit.h - Semantic Analysis for Initializers --------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file provides supporting data types for initialization of objects. +// +//===----------------------------------------------------------------------===// +#ifndef LLVM_CLANG_SEMA_INIT_H +#define LLVM_CLANG_SEMA_INIT_H + +#include "SemaOverload.h" +#include "clang/AST/TypeLoc.h" +#include "clang/Parse/Action.h" +#include "clang/Basic/SourceLocation.h" +#include "llvm/ADT/PointerIntPair.h" +#include "llvm/ADT/SmallVector.h" +#include <cassert> + +namespace clang { + +class CXXBaseSpecifier; +class DeclaratorDecl; +class DeclaratorInfo; +class FieldDecl; +class FunctionDecl; +class ParmVarDecl; +class Sema; +class TypeLoc; +class VarDecl; + +/// \brief Describes an entity that is being initialized. +class InitializedEntity { +public: + /// \brief Specifies the kind of entity being initialized. + enum EntityKind { + /// \brief The entity being initialized is a variable. + EK_Variable, + /// \brief The entity being initialized is a function parameter. + EK_Parameter, + /// \brief The entity being initialized is the result of a function call. + EK_Result, + /// \brief The entity being initialized is an exception object that + /// is being thrown. + EK_Exception, + /// \brief The entity being initialized is a temporary object. + EK_Temporary, + /// \brief The entity being initialized is a base member subobject. + EK_Base, + /// \brief The entity being initialized is a non-static data member + /// subobject. + EK_Member + }; + +private: + /// \brief The kind of entity being initialized. + EntityKind Kind; + + /// \brief The type of the object or reference being initialized along with + /// its location information. + TypeLoc TL; + + union { + /// \brief When Kind == EK_Variable, EK_Parameter, or EK_Member, + /// the VarDecl, ParmVarDecl, or FieldDecl, respectively. + DeclaratorDecl *VariableOrMember; + + /// \brief When Kind == EK_Result or EK_Exception, the location of the + /// 'return' or 'throw' keyword, respectively. When Kind == EK_Temporary, + /// the location where the temporary is being created. + unsigned Location; + + /// \brief When Kind == EK_Base, the base specifier that provides the + /// base class. + CXXBaseSpecifier *Base; + }; + + InitializedEntity() { } + + /// \brief Create the initialization entity for a variable. + InitializedEntity(VarDecl *Var) + : Kind(EK_Variable), + VariableOrMember(reinterpret_cast<DeclaratorDecl*>(Var)) + { + InitDeclLoc(); + } + + /// \brief Create the initialization entity for a parameter. + InitializedEntity(ParmVarDecl *Parm) + : Kind(EK_Parameter), + VariableOrMember(reinterpret_cast<DeclaratorDecl*>(Parm)) + { + InitDeclLoc(); + } + + /// \brief Create the initialization entity for the result of a function, + /// throwing an object, or performing an explicit cast. + InitializedEntity(EntityKind Kind, SourceLocation Loc, TypeLoc TL) + : Kind(Kind), TL(TL), Location(Loc.getRawEncoding()) { } + + /// \brief Create the initialization entity for a member subobject. + InitializedEntity(FieldDecl *Member) + : Kind(EK_Member), + VariableOrMember(reinterpret_cast<DeclaratorDecl*>(Member)) + { + InitDeclLoc(); + } + + /// \brief Initialize type-location information from a declaration. + void InitDeclLoc(); + +public: + /// \brief Create the initialization entity for a variable. + static InitializedEntity InitializeVariable(VarDecl *Var) { + return InitializedEntity(Var); + } + + /// \brief Create the initialization entity for a parameter. + static InitializedEntity InitializeParameter(ParmVarDecl *Parm) { + return InitializedEntity(Parm); + } + + /// \brief Create the initialization entity for the result of a function. + static InitializedEntity InitializeResult(SourceLocation ReturnLoc, + TypeLoc TL) { + return InitializedEntity(EK_Result, ReturnLoc, TL); + } + + /// \brief Create the initialization entity for an exception object. + static InitializedEntity InitializeException(SourceLocation ThrowLoc, + TypeLoc TL) { + return InitializedEntity(EK_Exception, ThrowLoc, TL); + } + + /// \brief Create the initialization entity for a temporary. + static InitializedEntity InitializeTemporary(EntityKind Kind, TypeLoc TL) { + return InitializedEntity(Kind, SourceLocation(), TL); + } + + /// \brief Create the initialization entity for a base class subobject. + static InitializedEntity InitializeBase(ASTContext &Context, + CXXBaseSpecifier *Base); + + /// \brief Create the initialize entity for a member subobject. + static InitializedEntity InitializeMember(FieldDecl *Member) { + return InitializedEntity(Member); + } + + /// \brief Determine the kind of initialization. + EntityKind getKind() const { return Kind; } + + /// \brief Retrieve type being initialized. + TypeLoc getType() const { return TL; } + + /// \brief Determine the location of the 'return' keyword when initializing + /// the result of a function call. + SourceLocation getReturnLoc() const { + assert(getKind() == EK_Result && "No 'return' location!"); + return SourceLocation::getFromRawEncoding(Location); + } + + /// \brief Determine the location of the 'throw' keyword when initializing + /// an exception object. + SourceLocation getThrowLoc() const { + assert(getKind() == EK_Exception && "No 'throw' location!"); + return SourceLocation::getFromRawEncoding(Location); + } +}; + +/// \brief Describes the kind of initialization being performed, along with +/// location information for tokens related to the initialization (equal sign, +/// parentheses). +class InitializationKind { +public: + /// \brief The kind of initialization being performed. + enum InitKind { + IK_Direct, ///< Direct initialization + IK_Copy, ///< Copy initialization + IK_Default, ///< Default initialization + IK_Value ///< Value initialization + }; + +private: + /// \brief The kind of initialization that we're storing. + enum StoredInitKind { + SIK_Direct = IK_Direct, ///< Direct initialization + SIK_Copy = IK_Copy, ///< Copy initialization + SIK_Default = IK_Default, ///< Default initialization + SIK_Value = IK_Value, ///< Value initialization + SIK_DirectCast, ///< Direct initialization due to a cast + /// \brief Direct initialization due to a C-style or functional cast. + SIK_DirectCStyleOrFunctionalCast + }; + + /// \brief The kind of initialization being performed. + StoredInitKind Kind; + + /// \brief The source locations involved in the initialization. + SourceLocation Locations[3]; + + InitializationKind(StoredInitKind Kind, SourceLocation Loc1, + SourceLocation Loc2, SourceLocation Loc3) + : Kind(Kind) + { + Locations[0] = Loc1; + Locations[1] = Loc2; + Locations[2] = Loc3; + } + +public: + /// \brief Create a direct initialization. + static InitializationKind CreateDirect(SourceLocation InitLoc, + SourceLocation LParenLoc, + SourceLocation RParenLoc) { + return InitializationKind(SIK_Direct, InitLoc, LParenLoc, RParenLoc); + } + + /// \brief Create a direct initialization due to a cast. + static InitializationKind CreateCast(SourceRange TypeRange, + bool IsCStyleCast) { + return InitializationKind(IsCStyleCast? SIK_DirectCStyleOrFunctionalCast + : SIK_DirectCast, + TypeRange.getBegin(), TypeRange.getBegin(), + TypeRange.getEnd()); + } + + /// \brief Create a copy initialization. + static InitializationKind CreateCopy(SourceLocation InitLoc, + SourceLocation EqualLoc) { + return InitializationKind(SIK_Copy, InitLoc, EqualLoc, EqualLoc); + } + + /// \brief Create a default initialization. + static InitializationKind CreateDefault(SourceLocation InitLoc) { + return InitializationKind(SIK_Default, InitLoc, InitLoc, InitLoc); + } + + /// \brief Create a value initialization. + static InitializationKind CreateValue(SourceLocation InitLoc, + SourceLocation LParenLoc, + SourceLocation RParenLoc) { + return InitializationKind(SIK_Value, InitLoc, LParenLoc, RParenLoc); + } + + /// \brief Determine the initialization kind. + InitKind getKind() const { + if (Kind > SIK_Value) + return IK_Direct; + + return (InitKind)Kind; + } + + /// \brief Determine whether this initialization is an explicit cast. + bool isExplicitCast() const { + return Kind == SIK_DirectCast || Kind == SIK_DirectCStyleOrFunctionalCast; + } + + /// \brief Determine whether this initialization is a C-style cast. + bool isCStyleOrFunctionalCast() const { + return Kind == SIK_DirectCStyleOrFunctionalCast; + } + + /// \brief Retrieve the location at which initialization is occurring. + SourceLocation getLocation() const { return Locations[0]; } + + /// \brief Retrieve the source range that covers the initialization. + SourceRange getRange() const { + return SourceRange(Locations[0], Locations[2]); + } + + /// \brief Retrieve the location of the equal sign for copy initialization + /// (if present). + SourceLocation getEqualLoc() const { + assert(Kind == SIK_Copy && "Only copy initialization has an '='"); + return Locations[1]; + } + + /// \brief Retrieve the source range containing the locations of the open + /// and closing parentheses for value and direct initializations. + SourceRange getParenRange() const { + assert((getKind() == IK_Direct || Kind == SIK_Value) && + "Only direct- and value-initialization have parentheses"); + return SourceRange(Locations[1], Locations[2]); + } +}; + +/// \brief Describes the sequence of initializations required to initialize +/// a given object or reference with a set of arguments. +class InitializationSequence { +public: + /// \brief Describes the kind of initialization sequence computed. + /// + /// FIXME: Much of this information is in the initialization steps... why is + /// it duplicated here? + enum SequenceKind { + /// \brief A failed initialization sequence. The failure kind tells what + /// happened. + FailedSequence = 0, + + /// \brief A dependent initialization, which could not be + /// type-checked due to the presence of dependent types or + /// dependently-type expressions. + DependentSequence, + + /// \brief A user-defined conversion sequence. + UserDefinedConversion, + + /// \brief A constructor call. + ConstructorInitialization, + + /// \brief A reference binding. + ReferenceBinding, + + /// \brief List initialization + ListInitialization, + + /// \brief Zero-initialization. + ZeroInitialization + }; + + /// \brief Describes the kind of a particular step in an initialization + /// sequence. + enum StepKind { + /// \brief Resolve the address of an overloaded function to a specific + /// function declaration. + SK_ResolveAddressOfOverloadedFunction, + /// \brief Perform a derived-to-base cast, producing an rvalue. + SK_CastDerivedToBaseRValue, + /// \brief Perform a derived-to-base cast, producing an lvalue. + SK_CastDerivedToBaseLValue, + /// \brief Reference binding to an lvalue. + SK_BindReference, + /// \brief Reference binding to a temporary. + SK_BindReferenceToTemporary, + /// \brief Perform a user-defined conversion, either via a conversion + /// function or via a constructor. + SK_UserConversion, + /// \brief Perform a qualification conversion, producing an rvalue. + SK_QualificationConversionRValue, + /// \brief Perform a qualification conversion, producing an lvalue. + SK_QualificationConversionLValue, + /// \brief Perform an implicit conversion sequence. + SK_ConversionSequence, + /// \brief Perform list-initialization + SK_ListInitialization, + /// \brief Perform initialization via a constructor. + SK_ConstructorInitialization, + /// \brief Zero-initialize the object + SK_ZeroInitialization + }; + + /// \brief A single step in the initialization sequence. + class Step { + public: + /// \brief The kind of conversion or initialization step we are taking. + StepKind Kind; + + // \brief The type that results from this initialization. + QualType Type; + + union { + /// \brief When Kind == SK_ResolvedOverloadedFunction or Kind == + /// SK_UserConversion, the function that the expression should be + /// resolved to or the conversion function to call, respectively. + FunctionDecl *Function; + + /// \brief When Kind = SK_ConversionSequence, the implicit conversion + /// sequence + ImplicitConversionSequence *ICS; + }; + + void Destroy(); + }; + +private: + /// \brief The kind of initialization sequence computed. + enum SequenceKind SequenceKind; + + /// \brief Steps taken by this initialization. + llvm::SmallVector<Step, 4> Steps; + +public: + /// \brief Describes why initialization failed. + enum FailureKind { + /// \brief Too many initializers provided for a reference. + FK_TooManyInitsForReference, + /// \brief Array must be initialized with an initializer list. + FK_ArrayNeedsInitList, + /// \brief Array must be initialized with an initializer list or a + /// string literal. + FK_ArrayNeedsInitListOrStringLiteral, + /// \brief Cannot resolve the address of an overloaded function. + FK_AddressOfOverloadFailed, + /// \brief Overloading due to reference initialization failed. + FK_ReferenceInitOverloadFailed, + /// \brief Non-const lvalue reference binding to a temporary. + FK_NonConstLValueReferenceBindingToTemporary, + /// \brief Non-const lvalue reference binding to an lvalue of unrelated + /// type. + FK_NonConstLValueReferenceBindingToUnrelated, + /// \brief Rvalue reference binding to an lvalue. + FK_RValueReferenceBindingToLValue, + /// \brief Reference binding drops qualifiers. + FK_ReferenceInitDropsQualifiers, + /// \brief Reference binding failed. + FK_ReferenceInitFailed, + /// \brief Implicit conversion failed. + FK_ConversionFailed, + /// \brief Too many initializers for scalar + FK_TooManyInitsForScalar, + /// \brief Reference initialization from an initializer list + FK_ReferenceBindingToInitList, + /// \brief Initialization of some unused destination type with an + /// initializer list. + FK_InitListBadDestinationType, + /// \brief Overloading for a user-defined conversion failed. + FK_UserConversionOverloadFailed, + /// \brief Overloaded for initialization by constructor failed. + FK_ConstructorOverloadFailed + }; + +private: + /// \brief The reason why initialization failued. + FailureKind Failure; + + /// \brief The failed result of overload resolution. + OverloadingResult FailedOverloadResult; + + /// \brief The candidate set created when initialization failed. + OverloadCandidateSet FailedCandidateSet; + +public: + /// \brief Try to perform initialization of the given entity, creating a + /// record of the steps required to perform the initialization. + /// + /// The generated initialization sequence will either contain enough + /// information to diagnose + /// + /// \param S the semantic analysis object. + /// + /// \param Entity the entity being initialized. + /// + /// \param Kind the kind of initialization being performed. + /// + /// \param Args the argument(s) provided for initialization. + /// + /// \param NumArgs the number of arguments provided for initialization. + InitializationSequence(Sema &S, + const InitializedEntity &Entity, + const InitializationKind &Kind, + Expr **Args, + unsigned NumArgs); + + ~InitializationSequence(); + + /// \brief Perform the actual initialization of the given entity based on + /// the computed initialization sequence. + /// + /// \param S the semantic analysis object. + /// + /// \param Entity the entity being initialized. + /// + /// \param Kind the kind of initialization being performed. + /// + /// \param Args the argument(s) provided for initialization, ownership of + /// which is transfered into the routine. + /// + /// \param ResultType if non-NULL, will be set to the type of the + /// initialized object, which is the type of the declaration in most + /// cases. However, when the initialized object is a variable of + /// incomplete array type and the initializer is an initializer + /// list, this type will be set to the completed array type. + /// + /// \returns an expression that performs the actual object initialization, if + /// the initialization is well-formed. Otherwise, emits diagnostics + /// and returns an invalid expression. + Action::OwningExprResult Perform(Sema &S, + const InitializedEntity &Entity, + const InitializationKind &Kind, + Action::MultiExprArg Args, + QualType *ResultType = 0); + + /// \brief Diagnose an potentially-invalid initialization sequence. + /// + /// \returns true if the initialization sequence was ill-formed, + /// false otherwise. + bool Diagnose(Sema &S, + const InitializedEntity &Entity, + const InitializationKind &Kind, + Expr **Args, unsigned NumArgs); + + /// \brief Determine the kind of initialization sequence computed. + enum SequenceKind getKind() const { return SequenceKind; } + + /// \brief Set the kind of sequence computed. + void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; } + + /// \brief Determine whether the initialization sequence is valid. + operator bool() const { return SequenceKind != FailedSequence; } + + typedef llvm::SmallVector<Step, 4>::const_iterator step_iterator; + step_iterator step_begin() const { return Steps.begin(); } + step_iterator step_end() const { return Steps.end(); } + + /// \brief Add a new step in the initialization that resolves the address + /// of an overloaded function to a specific function declaration. + /// + /// \param Function the function to which the overloaded function reference + /// resolves. + void AddAddressOverloadResolutionStep(FunctionDecl *Function); + + /// \brief Add a new step in the initialization that performs a derived-to- + /// base cast. + /// + /// \param BaseType the base type to which we will be casting. + /// + /// \param IsLValue true if the result of this cast will be treated as + /// an lvalue. + void AddDerivedToBaseCastStep(QualType BaseType, bool IsLValue); + + /// \brief Add a new step binding a reference to an object. + /// + /// \param BindingTemporary true if we are binding a reference to a temporary + /// object (thereby extending its lifetime); false if we are binding to an + /// lvalue or an lvalue treated as an rvalue. + void AddReferenceBindingStep(QualType T, bool BindingTemporary); + + /// \brief Add a new step invoking a conversion function, which is either + /// a constructor or a conversion function. + void AddUserConversionStep(FunctionDecl *Function, QualType T); + + /// \brief Add a new step that performs a qualification conversion to the + /// given type. + void AddQualificationConversionStep(QualType Ty, bool IsLValue); + + /// \brief Add a new step that applies an implicit conversion sequence. + void AddConversionSequenceStep(const ImplicitConversionSequence &ICS, + QualType T); + + /// \brief Add a list-initialiation step + void AddListInitializationStep(QualType T); + + /// \brief Add a constructor-initialization step. + void AddConstructorInitializationStep(CXXConstructorDecl *Constructor, + QualType T); + + /// \brief Add a zero-initialization step. + void AddZeroInitializationStep(QualType T); + + /// \brief Note that this initialization sequence failed. + void SetFailed(FailureKind Failure) { + SequenceKind = FailedSequence; + this->Failure = Failure; + } + + /// \brief Note that this initialization sequence failed due to failed + /// overload resolution. + void SetOverloadFailure(FailureKind Failure, OverloadingResult Result); + + /// \brief Retrieve a reference to the candidate set when overload + /// resolution fails. + OverloadCandidateSet &getFailedCandidateSet() { + return FailedCandidateSet; + } + + /// \brief Determine why initialization failed. + FailureKind getFailureKind() const { + assert(getKind() == FailedSequence && "Not an initialization failure!"); + return Failure; + } +}; + +} // end namespace clang + +#endif // LLVM_CLANG_SEMA_INIT_H |