365 lines
13 KiB
C++
365 lines
13 KiB
C++
//===--- CGVTables.h - Emit LLVM Code for C++ vtables ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This contains code dealing with C++ code generation of virtual tables.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_CODEGEN_CGVTABLE_H
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#define CLANG_CODEGEN_CGVTABLE_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/GlobalVariable.h"
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#include "GlobalDecl.h"
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namespace clang {
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class CXXRecordDecl;
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namespace CodeGen {
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class CodeGenModule;
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/// ReturnAdjustment - A return adjustment.
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struct ReturnAdjustment {
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/// NonVirtual - The non-virtual adjustment from the derived object to its
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/// nearest virtual base.
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int64_t NonVirtual;
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/// VBaseOffsetOffset - The offset (in bytes), relative to the address point
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/// of the virtual base class offset.
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int64_t VBaseOffsetOffset;
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ReturnAdjustment() : NonVirtual(0), VBaseOffsetOffset(0) { }
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bool isEmpty() const { return !NonVirtual && !VBaseOffsetOffset; }
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friend bool operator==(const ReturnAdjustment &LHS,
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const ReturnAdjustment &RHS) {
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return LHS.NonVirtual == RHS.NonVirtual &&
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LHS.VBaseOffsetOffset == RHS.VBaseOffsetOffset;
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}
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friend bool operator<(const ReturnAdjustment &LHS,
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const ReturnAdjustment &RHS) {
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if (LHS.NonVirtual < RHS.NonVirtual)
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return true;
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return LHS.NonVirtual == RHS.NonVirtual &&
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LHS.VBaseOffsetOffset < RHS.VBaseOffsetOffset;
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}
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};
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/// ThisAdjustment - A 'this' pointer adjustment.
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struct ThisAdjustment {
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/// NonVirtual - The non-virtual adjustment from the derived object to its
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/// nearest virtual base.
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int64_t NonVirtual;
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/// VCallOffsetOffset - The offset (in bytes), relative to the address point,
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/// of the virtual call offset.
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int64_t VCallOffsetOffset;
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ThisAdjustment() : NonVirtual(0), VCallOffsetOffset(0) { }
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bool isEmpty() const { return !NonVirtual && !VCallOffsetOffset; }
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friend bool operator==(const ThisAdjustment &LHS,
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const ThisAdjustment &RHS) {
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return LHS.NonVirtual == RHS.NonVirtual &&
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LHS.VCallOffsetOffset == RHS.VCallOffsetOffset;
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}
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friend bool operator<(const ThisAdjustment &LHS,
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const ThisAdjustment &RHS) {
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if (LHS.NonVirtual < RHS.NonVirtual)
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return true;
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return LHS.NonVirtual == RHS.NonVirtual &&
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LHS.VCallOffsetOffset < RHS.VCallOffsetOffset;
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}
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};
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/// ThunkInfo - The 'this' pointer adjustment as well as an optional return
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/// adjustment for a thunk.
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struct ThunkInfo {
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/// This - The 'this' pointer adjustment.
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ThisAdjustment This;
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/// Return - The return adjustment.
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ReturnAdjustment Return;
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ThunkInfo() { }
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ThunkInfo(const ThisAdjustment &This, const ReturnAdjustment &Return)
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: This(This), Return(Return) { }
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friend bool operator==(const ThunkInfo &LHS, const ThunkInfo &RHS) {
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return LHS.This == RHS.This && LHS.Return == RHS.Return;
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}
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friend bool operator<(const ThunkInfo &LHS, const ThunkInfo &RHS) {
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if (LHS.This < RHS.This)
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return true;
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return LHS.This == RHS.This && LHS.Return < RHS.Return;
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}
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bool isEmpty() const { return This.isEmpty() && Return.isEmpty(); }
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};
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// BaseSubobject - Uniquely identifies a direct or indirect base class.
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// Stores both the base class decl and the offset from the most derived class to
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// the base class.
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class BaseSubobject {
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/// Base - The base class declaration.
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const CXXRecordDecl *Base;
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/// BaseOffset - The offset from the most derived class to the base class.
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uint64_t BaseOffset;
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public:
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BaseSubobject(const CXXRecordDecl *Base, uint64_t BaseOffset)
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: Base(Base), BaseOffset(BaseOffset) { }
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/// getBase - Returns the base class declaration.
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const CXXRecordDecl *getBase() const { return Base; }
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/// getBaseOffset - Returns the base class offset.
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uint64_t getBaseOffset() const { return BaseOffset; }
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friend bool operator==(const BaseSubobject &LHS, const BaseSubobject &RHS) {
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return LHS.Base == RHS.Base && LHS.BaseOffset == RHS.BaseOffset;
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}
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};
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} // end namespace CodeGen
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} // end namespace clang
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namespace llvm {
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template<> struct DenseMapInfo<clang::CodeGen::BaseSubobject> {
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static clang::CodeGen::BaseSubobject getEmptyKey() {
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return clang::CodeGen::BaseSubobject(
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DenseMapInfo<const clang::CXXRecordDecl *>::getEmptyKey(),
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DenseMapInfo<uint64_t>::getEmptyKey());
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}
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static clang::CodeGen::BaseSubobject getTombstoneKey() {
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return clang::CodeGen::BaseSubobject(
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DenseMapInfo<const clang::CXXRecordDecl *>::getTombstoneKey(),
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DenseMapInfo<uint64_t>::getTombstoneKey());
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}
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static unsigned getHashValue(const clang::CodeGen::BaseSubobject &Base) {
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return
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DenseMapInfo<const clang::CXXRecordDecl *>::getHashValue(Base.getBase()) ^
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DenseMapInfo<uint64_t>::getHashValue(Base.getBaseOffset());
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}
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static bool isEqual(const clang::CodeGen::BaseSubobject &LHS,
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const clang::CodeGen::BaseSubobject &RHS) {
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return LHS == RHS;
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}
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};
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// It's OK to treat BaseSubobject as a POD type.
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template <> struct isPodLike<clang::CodeGen::BaseSubobject> {
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static const bool value = true;
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};
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}
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namespace clang {
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namespace CodeGen {
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class CodeGenVTables {
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CodeGenModule &CGM;
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/// MethodVTableIndices - Contains the index (relative to the vtable address
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/// point) where the function pointer for a virtual function is stored.
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typedef llvm::DenseMap<GlobalDecl, int64_t> MethodVTableIndicesTy;
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MethodVTableIndicesTy MethodVTableIndices;
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typedef std::pair<const CXXRecordDecl *,
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const CXXRecordDecl *> ClassPairTy;
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/// VirtualBaseClassOffsetOffsets - Contains the vtable offset (relative to
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/// the address point) in bytes where the offsets for virtual bases of a class
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/// are stored.
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typedef llvm::DenseMap<ClassPairTy, int64_t>
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VirtualBaseClassOffsetOffsetsMapTy;
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VirtualBaseClassOffsetOffsetsMapTy VirtualBaseClassOffsetOffsets;
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/// VTables - All the vtables which have been defined.
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llvm::DenseMap<const CXXRecordDecl *, llvm::GlobalVariable *> VTables;
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/// NumVirtualFunctionPointers - Contains the number of virtual function
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/// pointers in the vtable for a given record decl.
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llvm::DenseMap<const CXXRecordDecl *, uint64_t> NumVirtualFunctionPointers;
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typedef llvm::SmallVector<ThunkInfo, 1> ThunkInfoVectorTy;
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typedef llvm::DenseMap<const CXXMethodDecl *, ThunkInfoVectorTy> ThunksMapTy;
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/// Thunks - Contains all thunks that a given method decl will need.
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ThunksMapTy Thunks;
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// The layout entry and a bool indicating whether we've actually emitted
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// the vtable.
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typedef llvm::PointerIntPair<uint64_t *, 1, bool> VTableLayoutData;
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typedef llvm::DenseMap<const CXXRecordDecl *, VTableLayoutData>
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VTableLayoutMapTy;
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/// VTableLayoutMap - Stores the vtable layout for all record decls.
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/// The layout is stored as an array of 64-bit integers, where the first
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/// integer is the number of vtable entries in the layout, and the subsequent
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/// integers are the vtable components.
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VTableLayoutMapTy VTableLayoutMap;
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typedef std::pair<const CXXRecordDecl *, BaseSubobject> BaseSubobjectPairTy;
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typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> AddressPointsMapTy;
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/// Address points - Address points for all vtables.
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AddressPointsMapTy AddressPoints;
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/// VTableAddressPointsMapTy - Address points for a single vtable.
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typedef llvm::DenseMap<BaseSubobject, uint64_t> VTableAddressPointsMapTy;
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typedef llvm::SmallVector<std::pair<uint64_t, ThunkInfo>, 1>
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VTableThunksTy;
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typedef llvm::DenseMap<const CXXRecordDecl *, VTableThunksTy>
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VTableThunksMapTy;
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/// VTableThunksMap - Contains thunks needed by vtables.
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VTableThunksMapTy VTableThunksMap;
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uint64_t getNumVTableComponents(const CXXRecordDecl *RD) const {
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assert(VTableLayoutMap.count(RD) && "No vtable layout for this class!");
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return VTableLayoutMap.lookup(RD).getPointer()[0];
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}
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const uint64_t *getVTableComponentsData(const CXXRecordDecl *RD) const {
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assert(VTableLayoutMap.count(RD) && "No vtable layout for this class!");
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uint64_t *Components = VTableLayoutMap.lookup(RD).getPointer();
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return &Components[1];
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}
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typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t> SubVTTIndiciesMapTy;
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/// SubVTTIndicies - Contains indices into the various sub-VTTs.
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SubVTTIndiciesMapTy SubVTTIndicies;
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typedef llvm::DenseMap<BaseSubobjectPairTy, uint64_t>
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SecondaryVirtualPointerIndicesMapTy;
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/// SecondaryVirtualPointerIndices - Contains the secondary virtual pointer
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/// indices.
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SecondaryVirtualPointerIndicesMapTy SecondaryVirtualPointerIndices;
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/// getNumVirtualFunctionPointers - Return the number of virtual function
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/// pointers in the vtable for a given record decl.
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uint64_t getNumVirtualFunctionPointers(const CXXRecordDecl *RD);
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void ComputeMethodVTableIndices(const CXXRecordDecl *RD);
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llvm::GlobalVariable *GenerateVTT(llvm::GlobalVariable::LinkageTypes Linkage,
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bool GenerateDefinition,
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const CXXRecordDecl *RD);
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/// EmitThunk - Emit a single thunk.
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void EmitThunk(GlobalDecl GD, const ThunkInfo &Thunk);
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/// ComputeVTableRelatedInformation - Compute and store all vtable related
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/// information (vtable layout, vbase offset offsets, thunks etc) for the
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/// given record decl.
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void ComputeVTableRelatedInformation(const CXXRecordDecl *RD,
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bool VTableRequired);
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/// CreateVTableInitializer - Create a vtable initializer for the given record
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/// decl.
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/// \param Components - The vtable components; this is really an array of
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/// VTableComponents.
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llvm::Constant *CreateVTableInitializer(const CXXRecordDecl *RD,
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const uint64_t *Components,
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unsigned NumComponents,
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const VTableThunksTy &VTableThunks);
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public:
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CodeGenVTables(CodeGenModule &CGM)
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: CGM(CGM) { }
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/// \brief True if the VTable of this record must be emitted in the
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/// translation unit.
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bool ShouldEmitVTableInThisTU(const CXXRecordDecl *RD);
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/// needsVTTParameter - Return whether the given global decl needs a VTT
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/// parameter, which it does if it's a base constructor or destructor with
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/// virtual bases.
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static bool needsVTTParameter(GlobalDecl GD);
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/// getSubVTTIndex - Return the index of the sub-VTT for the base class of the
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/// given record decl.
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uint64_t getSubVTTIndex(const CXXRecordDecl *RD, BaseSubobject Base);
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/// getSecondaryVirtualPointerIndex - Return the index in the VTT where the
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/// virtual pointer for the given subobject is located.
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uint64_t getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD,
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BaseSubobject Base);
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/// getMethodVTableIndex - Return the index (relative to the vtable address
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/// point) where the function pointer for the given virtual function is
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/// stored.
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uint64_t getMethodVTableIndex(GlobalDecl GD);
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/// getVirtualBaseOffsetOffset - Return the offset in bytes (relative to the
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/// vtable address point) where the offset of the virtual base that contains
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/// the given base is stored, otherwise, if no virtual base contains the given
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/// class, return 0. Base must be a virtual base class or an unambigious
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/// base.
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int64_t getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
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const CXXRecordDecl *VBase);
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/// getAddressPoint - Get the address point of the given subobject in the
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/// class decl.
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uint64_t getAddressPoint(BaseSubobject Base, const CXXRecordDecl *RD);
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/// GetAddrOfVTable - Get the address of the vtable for the given record decl.
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llvm::GlobalVariable *GetAddrOfVTable(const CXXRecordDecl *RD);
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/// EmitVTableDefinition - Emit the definition of the given vtable.
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void EmitVTableDefinition(llvm::GlobalVariable *VTable,
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llvm::GlobalVariable::LinkageTypes Linkage,
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const CXXRecordDecl *RD);
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/// GenerateConstructionVTable - Generate a construction vtable for the given
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/// base subobject.
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llvm::GlobalVariable *
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GenerateConstructionVTable(const CXXRecordDecl *RD, const BaseSubobject &Base,
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bool BaseIsVirtual,
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VTableAddressPointsMapTy& AddressPoints);
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llvm::GlobalVariable *getVTT(const CXXRecordDecl *RD);
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/// EmitThunks - Emit the associated thunks for the given global decl.
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void EmitThunks(GlobalDecl GD);
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/// GenerateClassData - Generate all the class data required to be generated
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/// upon definition of a KeyFunction. This includes the vtable, the
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/// rtti data structure and the VTT.
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///
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/// \param Linkage - The desired linkage of the vtable, the RTTI and the VTT.
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void GenerateClassData(llvm::GlobalVariable::LinkageTypes Linkage,
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const CXXRecordDecl *RD);
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};
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} // end namespace CodeGen
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} // end namespace clang
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#endif
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