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 "CGCXXABI.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)
  : CodeGenTypeCache(cgm), CGM(cgm),
    Target(CGM.getContext().Target), Builder(cgm.getModule().getContext()),
    AutoreleaseResult(false), BlockInfo(0), BlockPointer(0),
    NormalCleanupDest(0), EHCleanupDest(0), NextCleanupDestIndex(1),
    ExceptionSlot(0), EHSelectorSlot(0),
    DebugInfo(0), DisableDebugInfo(false), DidCallStackSave(false),
    IndirectBranch(0), SwitchInsn(0), CaseRangeBlock(0), UnreachableBlock(0),
    CXXThisDecl(0), CXXThisValue(0), CXXVTTDecl(0), CXXVTTValue(0),
    OutermostConditional(0), TerminateLandingPad(0), TerminateHandler(0),
    TrapBB(0) {

  CatchUndefined = getContext().getLangOptions().CatchUndefined;
  CGM.getCXXABI().getMangleContext().startNewFunction();
}


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

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

bool CodeGenFunction::hasAggregateLLVMType(QualType type) {
  switch (type.getCanonicalType()->getTypeClass()) {
#define TYPE(name, parent)
#define ABSTRACT_TYPE(name, parent)
#define NON_CANONICAL_TYPE(name, parent) case Type::name:
#define DEPENDENT_TYPE(name, parent) case Type::name:
#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(name, parent) case Type::name:
#include "clang/AST/TypeNodes.def"
    llvm_unreachable("non-canonical or dependent type in IR-generation");

  case Type::Builtin:
  case Type::Pointer:
  case Type::BlockPointer:
  case Type::LValueReference:
  case Type::RValueReference:
  case Type::MemberPointer:
  case Type::Vector:
  case Type::ExtVector:
  case Type::FunctionProto:
  case Type::FunctionNoProto:
  case Type::Enum:
  case Type::ObjCObjectPointer:
    return false;

  // Complexes, arrays, records, and Objective-C objects.
  case Type::Complex:
  case Type::ConstantArray:
  case Type::IncompleteArray:
  case Type::VariableArray:
  case Type::Record:
  case Type::ObjCObject:
  case Type::ObjCInterface:
    return true;
  }
  llvm_unreachable("unknown type kind!");
}

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.getBlock()->use_empty()) {
      ReturnBlock.getBlock()->replaceAllUsesWith(CurBB);
      delete ReturnBlock.getBlock();
    } else
      EmitBlock(ReturnBlock.getBlock());
    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.getBlock()->hasOneUse()) {
    llvm::BranchInst *BI =
      dyn_cast<llvm::BranchInst>(*ReturnBlock.getBlock()->use_begin());
    if (BI && BI->isUnconditional() &&
        BI->getSuccessor(0) == ReturnBlock.getBlock()) {
      // Reset insertion point and delete the branch.
      Builder.SetInsertPoint(BI->getParent());
      BI->eraseFromParent();
      delete ReturnBlock.getBlock();
      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.getBlock());
}

static void EmitIfUsed(CodeGenFunction &CGF, llvm::BasicBlock *BB) {
  if (!BB) return;
  if (!BB->use_empty())
    return