path: root/lib/CodeGen/CodeGenFunction.cpp

//===--- CodeGenFunction.cpp - Emit LLVM Code from ASTs for a Function ----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-function state used while generating code.
//
//===----------------------------------------------------------------------===//

#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "CGDebugInfo.h"
#include "CGException.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Intrinsics.h"
using namespace clang;
using namespace CodeGen;

CodeGenFunction::CodeGenFunction(CodeGenModule &cgm)
  : BlockFunction(cgm, *this, Builder), CGM(cgm),
    Target(CGM.getContext().Target),
    Builder(cgm.getModule().getContext()),
    ExceptionSlot(0), DebugInfo(0), IndirectBranch(0),
    SwitchInsn(0), CaseRangeBlock(0), InvokeDest(0),
    DidCallStackSave(false), UnreachableBlock(0),
    CXXThisDecl(0), CXXThisValue(0), CXXVTTDecl(0), CXXVTTValue(0),
    ConditionalBranchLevel(0), TerminateLandingPad(0), TerminateHandler(0),
    TrapBB(0) {
      
  // Get some frequently used types.
  LLVMPointerWidth = Target.getPointerWidth(0);
  llvm::LLVMContext &LLVMContext = CGM.getLLVMContext();
  IntPtrTy = llvm::IntegerType::get(LLVMContext, LLVMPointerWidth);
  Int32Ty  = llvm::Type::getInt32Ty(LLVMContext);
  Int64Ty  = llvm::Type::getInt64Ty(LLVMContext);
      
  Exceptions = getContext().getLangOptions().Exceptions;
  CatchUndefined = getContext().getLangOptions().CatchUndefined;
  CGM.getMangleContext().startNewFunction();
}

ASTContext &CodeGenFunction::getContext() const {
  return CGM.getContext();
}


llvm::Value *CodeGenFunction::GetAddrOfLocalVar(const VarDecl *VD) {
  llvm::Value *Res = LocalDeclMap[VD];
  assert(Res && "Invalid argument to GetAddrOfLocalVar(), no decl!");
  return Res;
}

llvm::Constant *
CodeGenFunction::GetAddrOfStaticLocalVar(const VarDecl *BVD) {
  return cast<llvm::Constant>(GetAddrOfLocalVar(BVD));
}

const llvm::Type *CodeGenFunction::ConvertTypeForMem(QualType T) {
  return CGM.getTypes().ConvertTypeForMem(T);
}

const llvm::Type *CodeGenFunction::ConvertType(QualType T) {
  return CGM.getTypes().ConvertType(T);
}

bool CodeGenFunction::hasAggregateLLVMType(QualType T) {
  return T->isRecordType() || T->isArrayType() || T->isAnyComplexType() ||
    T->isMemberFunctionPointerType();
}

void CodeGenFunction::EmitReturnBlock() {
  // For cleanliness, we try to avoid emitting the return block for
  // simple cases.
  llvm::BasicBlock *CurBB = Builder.GetInsertBlock();

  if (CurBB) {
    assert(!CurBB->getTerminator() && "Unexpected terminated block.");

    // We have a valid insert point, reuse it if it is empty or there are no
    // explicit jumps to the return block.
    if (CurBB->empty() || ReturnBlock.Block->use_empty()) {
      ReturnBlock.Block->replaceAllUsesWith(CurBB);
      delete ReturnBlock.Block;
    } else
      EmitBlock(ReturnBlock.Block);
    return;
  }

  // Otherwise, if the return block is the target of a single direct
  // branch then we can just put the code in that block instead. This
  // cleans up functions which started with a unified return block.
  if (ReturnBlock.Block->hasOneUse()) {
    llvm::BranchInst *BI =
      dyn_cast<llvm::BranchInst>(*ReturnBlock.Block->use_begin());
    if (BI && BI->isUnconditional() &&
        BI->getSuccessor(0) == ReturnBlock.Block) {
      // Reset insertion point and delete the branch.
      Builder.SetInsertPoint(BI->getParent());
      BI->eraseFromParent();
      delete ReturnBlock.Block;
      return;
    }
  }

  // FIXME: We are at an unreachable point, there is no reason to emit the block
  // unless it has uses. However, we still need a place to put the debug
  // region.end for now.

  EmitBlock(ReturnBlock.Block);
}

static void EmitIfUsed(CodeGenFunction &CGF, llvm