path: root/lib/CodeGen/CGBlocks.cpp

//===--- CGBlocks.cpp - Emit LLVM Code for declarations -------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit blocks.
//
//===----------------------------------------------------------------------===//

#include "CGDebugInfo.h"
#include "CodeGenFunction.h"
#include "CGObjCRuntime.h"
#include "CodeGenModule.h"
#include "clang/AST/DeclObjC.h"
#include "llvm/Module.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Target/TargetData.h"
#include <algorithm>

using namespace clang;
using namespace CodeGen;

CGBlockInfo::CGBlockInfo(const char *N)
  : Name(N), CXXThisRef(0), NeedsObjCSelf(false),
    HasCXXObject(false) {
    
  // Skip asm prefix, if any.
  if (Name && Name[0] == '\01')
    ++Name;
}


llvm::Constant *CodeGenFunction::
BuildDescriptorBlockDecl(const BlockExpr *BE, const CGBlockInfo &Info,
                         const llvm::StructType* Ty,
                         llvm::Constant *BlockVarLayout,
                         std::vector<HelperInfo> *NoteForHelper) {
  CharUnits Size = Info.BlockSize;
  const llvm::Type *UnsignedLongTy
    = CGM.getTypes().ConvertType(getContext().UnsignedLongTy);
  llvm::Constant *C;
  std::vector<llvm::Constant*> Elts;

  // reserved
  C = llvm::ConstantInt::get(UnsignedLongTy, 0);
  Elts.push_back(C);

  // Size
  // FIXME: What is the right way to say this doesn't fit?  We should give
  // a user diagnostic in that case.  Better fix would be to change the
  // API to size_t.
  C = llvm::ConstantInt::get(UnsignedLongTy, Size.getQuantity());
  Elts.push_back(C);

  // optional copy/dispose helpers
  if (Info.BlockHasCopyDispose) {
    // copy_func_helper_decl
    Elts.push_back(BuildCopyHelper(Ty, NoteForHelper));

    // destroy_func_decl
    Elts.push_back(BuildDestroyHelper(Ty, NoteForHelper));
  }

  // Signature.  non-optional ObjC-style method descriptor @encode sequence
  std::string BlockTypeEncoding;
  CGM.getContext().getObjCEncodingForBlock(BE, BlockTypeEncoding);

  Elts.push_back(llvm::ConstantExpr::getBitCast(
          CGM.GetAddrOfConstantCString(BlockTypeEncoding), PtrToInt8Ty));
  
  // Layout.
  C = BlockVarLayout;
    
  Elts.push_back(C);

  C = llvm::ConstantStruct::get(VMContext, Elts, false);

  C = new llvm::GlobalVariable(CGM.getModule(), C->getType(),