path: root/lib/CodeGen/IntrinsicLowering.cpp

//===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the IntrinsicLowering class.
//
//===----------------------------------------------------------------------===//

#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/IntrinsicLowering.h"
#include "llvm/Support/IRBuilder.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallVector.h"
using namespace llvm;

template <class ArgIt>
static void EnsureFunctionExists(Module &M, const char *Name,
                                 ArgIt ArgBegin, ArgIt ArgEnd,
                                 const Type *RetTy) {
  // Insert a correctly-typed definition now.
  std::vector<const Type *> ParamTys;
  for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
    ParamTys.push_back(I->getType());
  M.getOrInsertFunction(Name, FunctionType::get(RetTy, ParamTys, false));
}

static void EnsureFPIntrinsicsExist(Module &M, Function *Fn,
                                    const char *FName,
                                    const char *DName, const char *LDName) {
  // Insert definitions for all the floating point types.
  switch((int)Fn->arg_begin()->getType()->getTypeID()) {
  case Type::FloatTyID:
    EnsureFunctionExists(M, FName, Fn->arg_begin(), Fn->arg_end(),
                         Type::FloatTy);
    break;
  case Type::DoubleTyID:
    EnsureFunctionExists(M, DName, Fn->arg_begin(), Fn->arg_end(),
                         Type::DoubleTy);
    break;
  case Type::X86_FP80TyID:
  case Type::FP128TyID:
  case Type::PPC_FP128TyID:
    EnsureFunctionExists(M, LDName, Fn->arg_begin(), Fn->arg_end(),
                         Fn->arg_begin()->getType());
    break;
  }
}

/// ReplaceCallWith - This function is used when we want to lower an intrinsic
/// call to a call of an external function.  This handles hard cases such as
/// when there was already a prototype for the external function, and if that
/// prototype doesn't match the arguments we expect to pass in.
template <class ArgIt>
static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
                                 ArgIt ArgBegin, ArgIt ArgEnd,
                                 const Type *RetTy) {
  // If we haven't already looked up this function, check to see if the
  // program already contains a function with this name.
  Module *M = CI->getParent()->getParent()->getParent();
  // Get or insert the definition now.
  std::vector<const Type *> ParamTys;
  for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
    ParamTys.push_back((*I)->getType());
  Constant* FCache = M->getOrInsertFunction(NewFn,
                                  FunctionType::get(RetTy, ParamTys, false));

  IRBuilder<> Builder(CI->getParent(), CI);
  SmallVector<Value *, 8> Args(ArgBegin, ArgEnd);
  CallInst *NewCI = Builder.CreateCall(FCache, Args.begin(), Args.end());
  NewCI->setName(CI->getName());
  if (!CI->use_empty())
    CI->replaceAllUsesWith(NewCI);
  return NewCI;
}

void IntrinsicLowering::AddPrototypes(Module &M) {
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (I->isDeclaration() && !I->use_empty())
      switch (I->getIntrinsicID()) {
      default: break;
      case Intrinsic::setjmp:
        EnsureFunctionExists(M, "setjmp", I->arg_begin(), I->arg_end(),
                             Type::Int32Ty);
        break;
      case Intrinsic::longjmp:
        EnsureFunctionExists(M, "longjmp", I->arg_begin(), I->arg_end(),
                             Type::VoidTy);
        break;
      case Intrinsic::siglongjmp:
        EnsureFunctionExists(M, "abort", I->arg_end(), I->arg_end(),
                             Type::VoidTy);
        break;
      case Intrinsic::memcpy:
        M.getOrInsertFunction("memcpy", PointerType::getUnqual(Type::Int8Ty),
                              PointerType::getUnqual(Type::Int8Ty), 
                              PointerType::getUnqual(Type::Int8Ty), 
                              TD.getIntPtrType(), (Type *)0);
        break;
      case Intrinsic::memmove:
        M.getOrInsertFunction("memmove", PointerType::getUnqual(Type::Int8Ty),
                              PointerType::getUnqual(Type::Int8Ty), 
                              PointerType::getUnqual(Type::Int8Ty), 
                              TD.getIntPtrType(), (Type *)0);
        break;
      case Intrinsic::memset:
        M.getOrInsertFunction("memset", PointerType::getUnqual(Type::Int8Ty),
                              PointerType::getUnqual(Type::Int8Ty), 
                              Type::Int32Ty, 
                              TD.getIntPtrType(), (Type *)0);
        break;