path: root/lib/CodeGen/ItaniumCXXABI.cpp

//===------- ItaniumCXXABI.cpp - Emit LLVM Code from ASTs for a Module ----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This provides C++ code generation targeting the Itanium C++ ABI.  The class
// in this file generates structures that follow the Itanium C++ ABI, which is
// documented at:
//  http://www.codesourcery.com/public/cxx-abi/abi.html
//  http://www.codesourcery.com/public/cxx-abi/abi-eh.html
//
// It also supports the closely-related ARM ABI, documented at:
// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
//
//===----------------------------------------------------------------------===//

#include "CGCXXABI.h"
#include "CGRecordLayout.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include <clang/AST/Mangle.h>
#include <clang/AST/Type.h>
#include <llvm/Intrinsics.h>
#include <llvm/Target/TargetData.h>
#include <llvm/Value.h>

using namespace clang;
using namespace CodeGen;

namespace {
class ItaniumCXXABI : public CodeGen::CGCXXABI {
private:
  llvm::IntegerType *PtrDiffTy;
protected:
  bool IsARM;

  // It's a little silly for us to cache this.
  llvm::IntegerType *getPtrDiffTy() {
    if (!PtrDiffTy) {
      QualType T = getContext().getPointerDiffType();
      llvm::Type *Ty = CGM.getTypes().ConvertType(T);
      PtrDiffTy = cast<llvm::IntegerType>(Ty);
    }
    return PtrDiffTy;
  }

  bool NeedsArrayCookie(const CXXNewExpr *expr);
  bool NeedsArrayCookie(const CXXDeleteExpr *expr,
                        QualType elementType);

public:
  ItaniumCXXABI(CodeGen::CodeGenModule &CGM, bool IsARM = false) :
    CGCXXABI(CGM), PtrDiffTy(0), IsARM(IsARM) { }

  bool isZeroInitializable(const MemberPointerType *MPT);

  llvm::Type *ConvertMemberPointerType(const MemberPointerType *MPT);

  llvm::Value *EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF,
                                               llvm::Value *&This,
                                               llvm::Value *MemFnPtr,
                                               const MemberPointerType *MPT);

  llvm::Value *EmitMemberDataPointerAddress(CodeGenFunction &CGF,
                                            llvm::Value *Base,
                                            llvm::Value *MemPtr,
                                            const MemberPointerType *MPT);

  llvm::Value *EmitMemberPointerConversion(CodeGenFunction &CGF,
                                           const CastExpr *E,
                                           llvm::Value *Src);

  llvm::Constant *EmitNullMemberPointer(const MemberPointerType *MPT);

  llvm::Constant *EmitMemberPointer(const CXXMethodDecl *MD);
  llvm::Constant *EmitMemberDataPointer(const MemberPointerType *MPT,
                                        CharUnits offset);
  llvm::Constant *EmitMemberPointer(const APValue &MP, QualType MPT);
  llvm::Constant *BuildMemberPointer(const CXXMethodDecl *MD,
                                     CharUnits ThisAdjustment);

  llvm::Value *EmitMemberPointerComparison(CodeGenFunction &CGF,
                                           llvm::Value *L,
                                           llvm::Value *R,
                                           const MemberPointerType *MPT,
                                           bool Inequality);

  llvm::Value *EmitMemberPointerIsNotNull(CodeGenFunction &CGF,
                                          llvm::Value *Addr,
                                          const MemberPointerType *MPT);

  void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
                                 CXXCtorType T,
                                 CanQualType &ResTy,
                                 SmallVectorImpl<CanQualType> &ArgTys);

  void BuildDestructorSignature(const CXXDestructorDecl *Dtor,
                                CXXDtorType T,
                                CanQualType &ResTy,
                                SmallVectorI