path: root/lib/CodeGen/CGVtable.cpp

//===--- CGVtable.cpp - Emit LLVM Code for C++ vtables --------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with C++ code generation of virtual tables.
//
//===----------------------------------------------------------------------===//

#include "CodeGenModule.h"
#include "CodeGenFunction.h"

#include "clang/AST/RecordLayout.h"
#include <cstdio>

using namespace clang;
using namespace CodeGen;

class VtableBuilder {
public:
  /// Index_t - Vtable index type.
  typedef uint64_t Index_t;
private:
  std::vector<llvm::Constant *> &methods;
  std::vector<llvm::Constant *> submethods;
  llvm::Type *Ptr8Ty;
  /// Class - The most derived class that this vtable is being built for.
  const CXXRecordDecl *Class;
  /// LayoutClass - The most derived class used for virtual base layout
  /// information.
  const CXXRecordDecl *LayoutClass;
  /// LayoutOffset - The offset for Class in LayoutClass.
  uint64_t LayoutOffset;
  /// BLayout - Layout for the most derived class that this vtable is being
  /// built for.
  const ASTRecordLayout &BLayout;
  llvm::SmallSet<const CXXRecordDecl *, 32> IndirectPrimary;
  llvm::SmallSet<const CXXRecordDecl *, 32> SeenVBase;
  llvm::Constant *rtti;
  llvm::LLVMContext &VMContext;
  CodeGenModule &CGM;  // Per-module state.
  /// Index - Maps a method decl into a vtable index.  Useful for virtual
  /// dispatch codegen.
  llvm::DenseMap<GlobalDecl, Index_t> Index;
  llvm::DenseMap<GlobalDecl, Index_t> VCall;
  llvm::DenseMap<GlobalDecl, Index_t> VCallOffset;
  // This is the offset to the nearest virtual base
  llvm::DenseMap<GlobalDecl, Index_t> NonVirtualOffset;
  llvm::DenseMap<const CXXRecordDecl *, Index_t> VBIndex;

  typedef llvm::DenseMap<GlobalDecl, int> Pures_t;
  Pures_t Pures;
  typedef std::pair<Index_t, Index_t>  CallOffset;
  typedef llvm::DenseMap<GlobalDecl, CallOffset> Thunks_t;
  Thunks_t Thunks;
  typedef llvm::DenseMap<GlobalDecl,
                         std::pair<std::pair<CallOffset, CallOffset>,
                                   CanQualType> > CovariantThunks_t;
  CovariantThunks_t CovariantThunks;
  std::vector<Index_t> VCalls;

  typedef std::pair<const CXXRecordDecl *, uint64_t> CtorVtable_t;
  // subAddressPoints - Used to hold the AddressPoints (offsets) into the built
  // vtable for use in computing the initializers for the VTT.
  llvm::DenseMap<CtorVtable_t, int64_t> &subAddressPoints;

  typedef CXXRecordDecl::method_iterator method_iter;
  const bool Extern;
  const uint32_t LLVMPointerWidth;
  Index_t extra;
  typedef std::vector<std::pair<const CXXRecordDecl *, int64_t> > Path_t;
  llvm::Constant *cxa_pure;
  static llvm::DenseMap<CtorVtable_t, int64_t>&
  AllocAddressPoint(CodeGenModule &cgm, const CXXRecordDecl *l,
                    const CXXRecordDecl *c) {
    CodeGenModule::AddrMap_t *&oref = cgm.AddressPoints[l];
    if (oref == 0)
      oref = new CodeGenModule::AddrMap_t;

    llvm::DenseMap<CtorVtable_t, int64_t> *&ref = (*oref)[c];
    if (ref == 0)
      ref = new llvm::DenseMap<CtorVtable_t, int64_t>;
    return *ref;
  }
public:
  VtableBuilder(std::vector<llvm::Constant *> &meth, const CXXRecordDecl *c,
                const CXXRecordDecl *l, uint64_t lo, CodeGenModule &cgm)
    : methods(meth), Class(c), LayoutClass(l), LayoutOffset(lo),
      BLayout(cgm.getContext().getASTRecordLayout(l)),<