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;

llvm::Constant *CodeGenFunction::
BuildDescriptorBlockDecl(const BlockExpr *BE, bool BlockHasCopyDispose, CharUnits Size,
                         const llvm::StructType* Ty,
                         std::vector<HelperInfo> *NoteForHelper) {
  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 (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 = llvm::ConstantInt::get(UnsignedLongTy, 0);
  Elts.push_back(C);

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

  C = new llvm::GlobalVariable(CGM.getModule(), C->getType(), true,
                               llvm::GlobalValue::InternalLinkage,
                               C, "__block_descriptor_tmp");
  return C;
}

llvm::Constant *BlockModule::getNSConcreteGlobalBlock() {
  if (NSConcreteGlobalBlock == 0)
    NSConcreteGlobalBlock = CGM.CreateRuntimeVariable(PtrToInt8Ty,
                                                      "_NSConcreteGlobalBlock");
  return NSConcreteGlobalBlock;
}

llvm::Constant *BlockModule::getNSConcreteStackBlock() {
  if (NSConcreteStackBlock == 0)
    NSConcreteStackBlock = CGM.CreateRuntimeVariable(PtrToInt8Ty,
                                                     "_NSConcreteStackBlock");
  return NSConcreteStackBlock;
}

static void CollectBlockDeclRefInfo(
  const Stmt *S, CodeGenFunction::BlockInfo &Info,
  llvm::SmallSet<const DeclContext *, 16> &InnerContexts) {
  for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end();
       I != E; ++I)
    if (*I)
      CollectBlockDeclRefInfo(*I, Info, InnerContexts);