clang-1/lib/CodeGen/MicrosoftCXXABI.cpp

//===--- MicrosoftCXXABI.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 Microsoft Visual C++ ABI.
// The class in this file generates structures that follow the Microsoft
// Visual C++ ABI, which is actually not very well documented at all outside
// of Microsoft.
//
//===----------------------------------------------------------------------===//

#include "CGCXXABI.h"
#include "CodeGenModule.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"

using namespace clang;
using namespace CodeGen;

namespace {

class MicrosoftCXXABI : public CGCXXABI {
public:
  MicrosoftCXXABI(CodeGenModule &CGM) : CGCXXABI(CGM) {}

  void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
                                 CXXCtorType Type,
                                 CanQualType &ResTy,
                                 SmallVectorImpl<CanQualType> &ArgTys) {
    // 'this' is already in place
    // TODO: 'for base' flag
  }  

  void BuildDestructorSignature(const CXXDestructorDecl *Ctor,
                                CXXDtorType Type,
                                CanQualType &ResTy,
                                SmallVectorImpl<CanQualType> &ArgTys) {
    // 'this' is already in place
    // TODO: 'for base' flag
  }

  void BuildInstanceFunctionParams(CodeGenFunction &CGF,
                                   QualType &ResTy,
                                   FunctionArgList &Params) {
    BuildThisParam(CGF, Params);
    // TODO: 'for base' flag
  }

  void EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
    EmitThisParam(CGF);
    // TODO: 'for base' flag
  }

  // ==== Notes on array cookies =========
  //
  // MSVC seems to only use cookies when the class has a destructor; a
  // two-argument usual array deallocation function isn't sufficient.
  //
  // For example, this code prints "100" and "1":
  //   struct A {
  //     char x;
  //     void *operator new[](size_t sz) {
  //       printf("%u\n", sz);
  //       return malloc(sz);
  //     }
  //     void operator delete[](void *p, size_t sz) {
  //       printf("%u\n", sz);
  //       free(p);
  //     }
  //   };
  //   int main() {
  //     A *p = new A[100];
  //     delete[] p;
  //   }
  // Whereas it prints "104" and "104" if you give A a destructor.
  void ReadArrayCookie(CodeGenFunction &CGF, llvm::Value *Ptr,
                       const CXXDeleteExpr *expr,
                       QualType ElementType, llvm::Value *&NumElements,
                       llvm::Value *&AllocPtr, CharUnits &CookieSize) {
    CGF.CGM.ErrorUnsupported(expr, "don't know how to handle array cookies "
                                   "in the Microsoft C++ ABI");
  }
};

}

CGCXXABI *clang::CodeGen::CreateMicrosoftCXXABI(CodeGenModule &CGM) {
  return new MicrosoftCXXABI(CGM);
}