Esempio n. 1
0
/// cloneFunctionBody - Create a new function based on F and
/// insert it into module. Remove first argument. Use STy as
/// the return type for new function.
Function *SRETPromotion::cloneFunctionBody(Function *F, 
                                           const StructType *STy) {

  const FunctionType *FTy = F->getFunctionType();
  std::vector<const Type*> Params;

  // Attributes - Keep track of the parameter attributes for the arguments.
  SmallVector<AttributeWithIndex, 8> AttributesVec;
  const AttrListPtr &PAL = F->getAttributes();

  // Add any return attributes.
  if (Attributes attrs = PAL.getRetAttributes())
    AttributesVec.push_back(AttributeWithIndex::get(0, attrs));

  // Skip first argument.
  Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
  ++I;
  // 0th parameter attribute is reserved for return type.
  // 1th parameter attribute is for first 1st sret argument.
  unsigned ParamIndex = 2; 
  while (I != E) {
    Params.push_back(I->getType());
    if (Attributes Attrs = PAL.getParamAttributes(ParamIndex))
      AttributesVec.push_back(AttributeWithIndex::get(ParamIndex - 1, Attrs));
    ++I;
    ++ParamIndex;
  }

  // Add any fn attributes.
  if (Attributes attrs = PAL.getFnAttributes())
    AttributesVec.push_back(AttributeWithIndex::get(~0, attrs));


  FunctionType *NFTy = FunctionType::get(STy, Params, FTy->isVarArg());
  Function *NF = Function::Create(NFTy, F->getLinkage());
  NF->takeName(F);
  NF->copyAttributesFrom(F);
  NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end()));
  F->getParent()->getFunctionList().insert(F, NF);
  NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList());

  // Replace arguments
  I = F->arg_begin();
  E = F->arg_end();
  Function::arg_iterator NI = NF->arg_begin();
  ++I;
  while (I != E) {
    I->replaceAllUsesWith(NI);
    NI->takeName(I);
    ++I;
    ++NI;
  }

  return NF;
}