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Diffstat (limited to 'contrib/llvm/tools/clang/lib/CodeGen/CGCXXABI.h')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/CodeGen/CGCXXABI.h | 530 |
1 files changed, 530 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGCXXABI.h b/contrib/llvm/tools/clang/lib/CodeGen/CGCXXABI.h new file mode 100644 index 0000000..91e4970 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/CodeGen/CGCXXABI.h @@ -0,0 +1,530 @@ +//===----- CGCXXABI.h - Interface to C++ ABIs -------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This provides an abstract class for C++ code generation. Concrete subclasses +// of this implement code generation for specific C++ ABIs. +// +//===----------------------------------------------------------------------===// + +#ifndef CLANG_CODEGEN_CXXABI_H +#define CLANG_CODEGEN_CXXABI_H + +#include "CodeGenFunction.h" +#include "clang/Basic/LLVM.h" + +namespace llvm { +class Constant; +class Type; +class Value; +} + +namespace clang { +class CastExpr; +class CXXConstructorDecl; +class CXXDestructorDecl; +class CXXMethodDecl; +class CXXRecordDecl; +class FieldDecl; +class MangleContext; + +namespace CodeGen { +class CodeGenFunction; +class CodeGenModule; + +/// \brief Implements C++ ABI-specific code generation functions. +class CGCXXABI { +protected: + CodeGenModule &CGM; + std::unique_ptr<MangleContext> MangleCtx; + + CGCXXABI(CodeGenModule &CGM) + : CGM(CGM), MangleCtx(CGM.getContext().createMangleContext()) {} + +protected: + ImplicitParamDecl *&getThisDecl(CodeGenFunction &CGF) { + return CGF.CXXABIThisDecl; + } + llvm::Value *&getThisValue(CodeGenFunction &CGF) { + return CGF.CXXABIThisValue; + } + + /// Issue a diagnostic about unsupported features in the ABI. + void ErrorUnsupportedABI(CodeGenFunction &CGF, StringRef S); + + /// Get a null value for unsupported member pointers. + llvm::Constant *GetBogusMemberPointer(QualType T); + + ImplicitParamDecl *&getStructorImplicitParamDecl(CodeGenFunction &CGF) { + return CGF.CXXStructorImplicitParamDecl; + } + llvm::Value *&getStructorImplicitParamValue(CodeGenFunction &CGF) { + return CGF.CXXStructorImplicitParamValue; + } + + /// Perform prolog initialization of the parameter variable suitable + /// for 'this' emitted by buildThisParam. + void EmitThisParam(CodeGenFunction &CGF); + + ASTContext &getContext() const { return CGM.getContext(); } + + virtual bool requiresArrayCookie(const CXXDeleteExpr *E, QualType eltType); + virtual bool requiresArrayCookie(const CXXNewExpr *E); + +public: + + virtual ~CGCXXABI(); + + /// Gets the mangle context. + MangleContext &getMangleContext() { + return *MangleCtx; + } + + /// Returns true if the given constructor or destructor is one of the + /// kinds that the ABI says returns 'this' (only applies when called + /// non-virtually for destructors). + /// + /// There currently is no way to indicate if a destructor returns 'this' + /// when called virtually, and code generation does not support the case. + virtual bool HasThisReturn(GlobalDecl GD) const { return false; } + + /// If the C++ ABI requires the given type be returned in a particular way, + /// this method sets RetAI and returns true. + virtual bool classifyReturnType(CGFunctionInfo &FI) const = 0; + + /// Specify how one should pass an argument of a record type. + enum RecordArgABI { + /// Pass it using the normal C aggregate rules for the ABI, potentially + /// introducing extra copies and passing some or all of it in registers. + RAA_Default = 0, + + /// Pass it on the stack using its defined layout. The argument must be + /// evaluated directly into the correct stack position in the arguments area, + /// and the call machinery must not move it or introduce extra copies. + RAA_DirectInMemory, + + /// Pass it as a pointer to temporary memory. + RAA_Indirect + }; + + /// Returns true if C++ allows us to copy the memory of an object of type RD + /// when it is passed as an argument. + bool canCopyArgument(const CXXRecordDecl *RD) const; + + /// Returns how an argument of the given record type should be passed. + virtual RecordArgABI getRecordArgABI(const CXXRecordDecl *RD) const = 0; + + /// Returns true if the implicit 'sret' parameter comes after the implicit + /// 'this' parameter of C++ instance methods. + virtual bool isSRetParameterAfterThis() const { return false; } + + /// Find the LLVM type used to represent the given member pointer + /// type. + virtual llvm::Type * + ConvertMemberPointerType(const MemberPointerType *MPT); + + /// Load a member function from an object and a member function + /// pointer. Apply the this-adjustment and set 'This' to the + /// adjusted value. + virtual llvm::Value *EmitLoadOfMemberFunctionPointer( + CodeGenFunction &CGF, const Expr *E, llvm::Value *&This, + llvm::Value *MemPtr, const MemberPointerType *MPT); + + /// Calculate an l-value from an object and a data member pointer. + virtual llvm::Value * + EmitMemberDataPointerAddress(CodeGenFunction &CGF, const Expr *E, + llvm::Value *Base, llvm::Value *MemPtr, + const MemberPointerType *MPT); + + /// Perform a derived-to-base, base-to-derived, or bitcast member + /// pointer conversion. + virtual llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF, + const CastExpr *E, + llvm::Value *Src); + + /// Perform a derived-to-base, base-to-derived, or bitcast member + /// pointer conversion on a constant value. + virtual llvm::Constant *EmitMemberPointerConversion(const CastExpr *E, + llvm::Constant *Src); + + /// Return true if the given member pointer can be zero-initialized + /// (in the C++ sense) with an LLVM zeroinitializer. + virtual bool isZeroInitializable(const MemberPointerType *MPT); + + /// Create a null member pointer of the given type. + virtual llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT); + + /// Create a member pointer for the given method. + virtual llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD); + + /// Create a member pointer for the given field. + virtual llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT, + CharUnits offset); + + /// Create a member pointer for the given member pointer constant. + virtual llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT); + + /// Emit a comparison between two member pointers. Returns an i1. + virtual llvm::Value * + EmitMemberPointerComparison(CodeGenFunction &CGF, + llvm::Value *L, + llvm::Value *R, + const MemberPointerType *MPT, + bool Inequality); + + /// Determine if a member pointer is non-null. Returns an i1. + virtual llvm::Value * + EmitMemberPointerIsNotNull(CodeGenFunction &CGF, + llvm::Value *MemPtr, + const MemberPointerType *MPT); + +protected: + /// A utility method for computing the offset required for the given + /// base-to-derived or derived-to-base member-pointer conversion. + /// Does not handle virtual conversions (in case we ever fully + /// support an ABI that allows this). Returns null if no adjustment + /// is required. + llvm::Constant *getMemberPointerAdjustment(const CastExpr *E); + + /// \brief Computes the non-virtual adjustment needed for a member pointer + /// conversion along an inheritance path stored in an APValue. Unlike + /// getMemberPointerAdjustment(), the adjustment can be negative if the path + /// is from a derived type to a base type. + CharUnits getMemberPointerPathAdjustment(const APValue &MP); + +public: + /// Adjust the given non-null pointer to an object of polymorphic + /// type to point to the complete object. + /// + /// The IR type of the result should be a pointer but is otherwise + /// irrelevant. + virtual llvm::Value *adjustToCompleteObject(CodeGenFunction &CGF, + llvm::Value *ptr, + QualType type) = 0; + + virtual llvm::Constant *getAddrOfRTTIDescriptor(QualType Ty) = 0; + + virtual bool shouldTypeidBeNullChecked(bool IsDeref, + QualType SrcRecordTy) = 0; + virtual void EmitBadTypeidCall(CodeGenFunction &CGF) = 0; + virtual llvm::Value *EmitTypeid(CodeGenFunction &CGF, QualType SrcRecordTy, + llvm::Value *ThisPtr, + llvm::Type *StdTypeInfoPtrTy) = 0; + + virtual bool shouldDynamicCastCallBeNullChecked(bool SrcIsPtr, + QualType SrcRecordTy) = 0; + + virtual llvm::Value * + EmitDynamicCastCall(CodeGenFunction &CGF, llvm::Value *Value, + QualType SrcRecordTy, QualType DestTy, + QualType DestRecordTy, llvm::BasicBlock *CastEnd) = 0; + + virtual llvm::Value *EmitDynamicCastToVoid(CodeGenFunction &CGF, + llvm::Value *Value, + QualType SrcRecordTy, + QualType DestTy) = 0; + + virtual bool EmitBadCastCall(CodeGenFunction &CGF) = 0; + + virtual llvm::Value *GetVirtualBaseClassOffset(CodeGenFunction &CGF, + llvm::Value *This, + const CXXRecordDecl *ClassDecl, + const CXXRecordDecl *BaseClassDecl) = 0; + + /// Build the signature of the given constructor variant by adding + /// any required parameters. For convenience, ArgTys has been initialized + /// with the type of 'this' and ResTy has been initialized with the type of + /// 'this' if HasThisReturn(GlobalDecl(Ctor, T)) is true or 'void' otherwise + /// (although both may be changed by the ABI). + /// + /// If there are ever any ABIs where the implicit parameters are + /// intermixed with the formal parameters, we can address those + /// then. + virtual void BuildConstructorSignature(const CXXConstructorDecl *Ctor, + CXXCtorType T, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) = 0; + + virtual llvm::BasicBlock *EmitCtorCompleteObjectHandler(CodeGenFunction &CGF, + const CXXRecordDecl *RD); + + /// Emit the code to initialize hidden members required + /// to handle virtual inheritance, if needed by the ABI. + virtual void + initializeHiddenVirtualInheritanceMembers(CodeGenFunction &CGF, + const CXXRecordDecl *RD) {} + + /// Emit constructor variants required by this ABI. + virtual void EmitCXXConstructors(const CXXConstructorDecl *D) = 0; + + /// Build the signature of the given destructor variant by adding + /// any required parameters. For convenience, ArgTys has been initialized + /// with the type of 'this' and ResTy has been initialized with the type of + /// 'this' if HasThisReturn(GlobalDecl(Dtor, T)) is true or 'void' otherwise + /// (although both may be changed by the ABI). + virtual void BuildDestructorSignature(const CXXDestructorDecl *Dtor, + CXXDtorType T, + CanQualType &ResTy, + SmallVectorImpl<CanQualType> &ArgTys) = 0; + + /// Returns true if the given destructor type should be emitted as a linkonce + /// delegating thunk, regardless of whether the dtor is defined in this TU or + /// not. + virtual bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor, + CXXDtorType DT) const = 0; + + /// Emit destructor variants required by this ABI. + virtual void EmitCXXDestructors(const CXXDestructorDecl *D) = 0; + + /// Get the type of the implicit "this" parameter used by a method. May return + /// zero if no specific type is applicable, e.g. if the ABI expects the "this" + /// parameter to point to some artificial offset in a complete object due to + /// vbases being reordered. + virtual const CXXRecordDecl * + getThisArgumentTypeForMethod(const CXXMethodDecl *MD) { + return MD->getParent(); + } + + /// Perform ABI-specific "this" argument adjustment required prior to + /// a call of a virtual function. + /// The "VirtualCall" argument is true iff the call itself is virtual. + virtual llvm::Value * + adjustThisArgumentForVirtualFunctionCall(CodeGenFunction &CGF, GlobalDecl GD, + llvm::Value *This, + bool VirtualCall) { + return This; + } + + /// Build a parameter variable suitable for 'this'. + void buildThisParam(CodeGenFunction &CGF, FunctionArgList &Params); + + /// Insert any ABI-specific implicit parameters into the parameter list for a + /// function. This generally involves extra data for constructors and + /// destructors. + /// + /// ABIs may also choose to override the return type, which has been + /// initialized with the type of 'this' if HasThisReturn(CGF.CurGD) is true or + /// the formal return type of the function otherwise. + virtual void addImplicitStructorParams(CodeGenFunction &CGF, QualType &ResTy, + FunctionArgList &Params) = 0; + + /// Perform ABI-specific "this" parameter adjustment in a virtual function + /// prologue. + virtual llvm::Value *adjustThisParameterInVirtualFunctionPrologue( + CodeGenFunction &CGF, GlobalDecl GD, llvm::Value *This) { + return This; + } + + /// Emit the ABI-specific prolog for the function. + virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0; + + /// Add any ABI-specific implicit arguments needed to call a constructor. + /// + /// \return The number of args added to the call, which is typically zero or + /// one. + virtual unsigned + addImplicitConstructorArgs(CodeGenFunction &CGF, const CXXConstructorDecl *D, + CXXCtorType Type, bool ForVirtualBase, + bool Delegating, CallArgList &Args) = 0; + + /// Emit the destructor call. + virtual void EmitDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *DD, CXXDtorType Type, + bool ForVirtualBase, bool Delegating, + llvm::Value *This) = 0; + + /// Emits the VTable definitions required for the given record type. + virtual void emitVTableDefinitions(CodeGenVTables &CGVT, + const CXXRecordDecl *RD) = 0; + + /// Get the address point of the vtable for the given base subobject while + /// building a constructor or a destructor. On return, NeedsVirtualOffset + /// tells if a virtual base adjustment is needed in order to get the offset + /// of the base subobject. + virtual llvm::Value *getVTableAddressPointInStructor( + CodeGenFunction &CGF, const CXXRecordDecl *RD, BaseSubobject Base, + const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) = 0; + + /// Get the address point of the vtable for the given base subobject while + /// building a constexpr. + virtual llvm::Constant * + getVTableAddressPointForConstExpr(BaseSubobject Base, + const CXXRecordDecl *VTableClass) = 0; + + /// Get the address of the vtable for the given record decl which should be + /// used for the vptr at the given offset in RD. + virtual llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD, + CharUnits VPtrOffset) = 0; + + /// Build a virtual function pointer in the ABI-specific way. + virtual llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, + GlobalDecl GD, + llvm::Value *This, + llvm::Type *Ty) = 0; + + /// Emit the ABI-specific virtual destructor call. + virtual void EmitVirtualDestructorCall(CodeGenFunction &CGF, + const CXXDestructorDecl *Dtor, + CXXDtorType DtorType, + SourceLocation CallLoc, + llvm::Value *This) = 0; + + virtual void adjustCallArgsForDestructorThunk(CodeGenFunction &CGF, + GlobalDecl GD, + CallArgList &CallArgs) {} + + /// Emit any tables needed to implement virtual inheritance. For Itanium, + /// this emits virtual table tables. For the MSVC++ ABI, this emits virtual + /// base tables. + virtual void emitVirtualInheritanceTables(const CXXRecordDecl *RD) = 0; + + virtual void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, + GlobalDecl GD, bool ReturnAdjustment) = 0; + + virtual llvm::Value *performThisAdjustment(CodeGenFunction &CGF, + llvm::Value *This, + const ThisAdjustment &TA) = 0; + + virtual llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, + llvm::Value *Ret, + const ReturnAdjustment &RA) = 0; + + virtual void EmitReturnFromThunk(CodeGenFunction &CGF, + RValue RV, QualType ResultType); + + /// Gets the pure virtual member call function. + virtual StringRef GetPureVirtualCallName() = 0; + + /// Gets the deleted virtual member call name. + virtual StringRef GetDeletedVirtualCallName() = 0; + + /**************************** Array cookies ******************************/ + + /// Returns the extra size required in order to store the array + /// cookie for the given new-expression. May return 0 to indicate that no + /// array cookie is required. + /// + /// Several cases are filtered out before this method is called: + /// - non-array allocations never need a cookie + /// - calls to \::operator new(size_t, void*) never need a cookie + /// + /// \param expr - the new-expression being allocated. + virtual CharUnits GetArrayCookieSize(const CXXNewExpr *expr); + + /// Initialize the array cookie for the given allocation. + /// + /// \param NewPtr - a char* which is the presumed-non-null + /// return value of the allocation function + /// \param NumElements - the computed number of elements, + /// potentially collapsed from the multidimensional array case; + /// always a size_t + /// \param ElementType - the base element allocated type, + /// i.e. the allocated type after stripping all array types + virtual llvm::Value *InitializeArrayCookie(CodeGenFunction &CGF, + llvm::Value *NewPtr, + llvm::Value *NumElements, + const CXXNewExpr *expr, + QualType ElementType); + + /// Reads the array cookie associated with the given pointer, + /// if it has one. + /// + /// \param Ptr - a pointer to the first element in the array + /// \param ElementType - the base element type of elements of the array + /// \param NumElements - an out parameter which will be initialized + /// with the number of elements allocated, or zero if there is no + /// cookie + /// \param AllocPtr - an out parameter which will be initialized + /// with a char* pointing to the address returned by the allocation + /// function + /// \param CookieSize - an out parameter which will be initialized + /// with the size of the cookie, or zero if there is no cookie + virtual void ReadArrayCookie(CodeGenFunction &CGF, llvm::Value *Ptr, + const CXXDeleteExpr *expr, + QualType ElementType, llvm::Value *&NumElements, + llvm::Value *&AllocPtr, CharUnits &CookieSize); + + /// Return whether the given global decl needs a VTT parameter. + virtual bool NeedsVTTParameter(GlobalDecl GD); + +protected: + /// Returns the extra size required in order to store the array + /// cookie for the given type. Assumes that an array cookie is + /// required. + virtual CharUnits getArrayCookieSizeImpl(QualType elementType); + + /// Reads the array cookie for an allocation which is known to have one. + /// This is called by the standard implementation of ReadArrayCookie. + /// + /// \param ptr - a pointer to the allocation made for an array, as a char* + /// \param cookieSize - the computed cookie size of an array + /// + /// Other parameters are as above. + /// + /// \return a size_t + virtual llvm::Value *readArrayCookieImpl(CodeGenFunction &IGF, + llvm::Value *ptr, + CharUnits cookieSize); + +public: + + /*************************** Static local guards ****************************/ + + /// Emits the guarded initializer and destructor setup for the given + /// variable, given that it couldn't be emitted as a constant. + /// If \p PerformInit is false, the initialization has been folded to a + /// constant and should not be performed. + /// + /// The variable may be: + /// - a static local variable + /// - a static data member of a class template instantiation + virtual void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D, + llvm::GlobalVariable *DeclPtr, + bool PerformInit) = 0; + + /// Emit code to force the execution of a destructor during global + /// teardown. The default implementation of this uses atexit. + /// + /// \param dtor - a function taking a single pointer argument + /// \param addr - a pointer to pass to the destructor function. + virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D, + llvm::Constant *dtor, llvm::Constant *addr); + + /*************************** thread_local initialization ********************/ + + /// Emits ABI-required functions necessary to initialize thread_local + /// variables in this translation unit. + /// + /// \param Decls The thread_local declarations in this translation unit. + /// \param InitFunc If this translation unit contains any non-constant + /// initialization or non-trivial destruction for thread_local + /// variables, a function to perform the initialization. Otherwise, 0. + virtual void EmitThreadLocalInitFuncs( + ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls, + llvm::Function *InitFunc); + + /// Emit a reference to a non-local thread_local variable (including + /// triggering the initialization of all thread_local variables in its + /// translation unit). + virtual LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, + const VarDecl *VD, + QualType LValType); +}; + +// Create an instance of a C++ ABI class: + +/// Creates an Itanium-family ABI. +CGCXXABI *CreateItaniumCXXABI(CodeGenModule &CGM); + +/// Creates a Microsoft-family ABI. +CGCXXABI *CreateMicrosoftCXXABI(CodeGenModule &CGM); + +} +} + +#endif |
