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//===-- AutoUpgrade.cpp - Implement auto-upgrade helper functions ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chandler Carruth and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the auto-upgrade helper functions
//
//===----------------------------------------------------------------------===//
#include "llvm/AutoUpgrade.h"
#include "llvm/Function.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/ParameterAttributes.h"
#include "llvm/Intrinsics.h"
using namespace llvm;
Function* llvm::UpgradeIntrinsicFunction(Function *F) {
assert(F && "Illegal to upgrade a non-existent Function.");
// Get the Function's name.
const std::string& Name = F->getName();
// Convenience
const FunctionType *FTy = F->getFunctionType();
// Quickly eliminate it, if it's not a candidate.
if (Name.length() <= 8 || Name[0] != 'l' || Name[1] != 'l' ||
Name[2] != 'v' || Name[3] != 'm' || Name[4] != '.')
return 0;
Module *M = F->getParent();
switch (Name[5]) {
default: break;
case 'b':
// This upgrades the name of the llvm.bswap intrinsic function to only use
// a single type name for overloading. We only care about the old format
// 'llvm.bswap.i*.i*', so check for 'bswap.' and then for there being
// a '.' after 'bswap.'
if (Name.compare(5,6,"bswap.",6) == 0) {
std::string::size_type delim = Name.find('.',11);
if (delim != std::string::npos) {
// Construct the new name as 'llvm.bswap' + '.i*'
F->setName(Name.substr(0,10)+Name.substr(delim));
return F;
}
}
break;
case 'c':
// We only want to fix the 'llvm.ct*' intrinsics which do not have the
// correct return type, so we check for the name, and then check if the
// return type does not match the parameter type.
if ( (Name.compare(5,5,"ctpop",5) == 0 ||
Name.compare(5,4,"ctlz",4) == 0 ||
Name.compare(5,4,"cttz",4) == 0) &&
FTy->getReturnType() != FTy->getParamType(0)) {
// We first need to change the name of the old (bad) intrinsic, because
// its type is incorrect, but we cannot overload that name. We
// arbitrarily unique it here allowing us to construct a correctly named
// and typed function below.
F->setName("");
// Now construct the new intrinsic with the correct name and type. We
// leave the old function around in order to query its type, whatever it
// may be, and correctly convert up to the new type.
return cast<Function>(M->getOrInsertFunction(Name,
FTy->getParamType(0),
FTy->getParamType(0),
(Type *)0));
}
break;
case 'p':
// This upgrades the llvm.part.select overloaded intrinsic names to only
// use one type specifier in the name. We only care about the old format
// 'llvm.part.select.i*.i*', and solve as above with bswap.
if (Name.compare(5,12,"part.select.",12) == 0) {
std::string::size_type delim = Name.find('.',17);
if (delim != std::string::npos) {
// Construct a new name as 'llvm.part.select' + '.i*'
F->setName(Name.substr(0,16)+Name.substr(delim));
return F;
}
break;
}
// This upgrades the llvm.part.set intrinsics similarly as above, however
// we care about 'llvm.part.set.i*.i*.i*', but only the first two types
// must match. There is an additional type specifier after these two
// matching types that we must retain when upgrading. Thus, we require
// finding 2 periods, not just one, after the intrinsic name.
if (Name.compare(5,9,"part.set.",9) == 0) {
std::string::size_type delim = Name.find('.',14);
if (delim != std::string::npos &&
Name.find('.',delim+1) != std::string::npos) {
// Construct a new name as 'llvm.part.select' + '.i*.i*'
F->setName(Name.substr(0,13)+Name.substr(delim));
return F;
}
break;
}
break;
}
// This may not belong here. This function is effectively being overloaded
// to both detect an intrinsic which needs upgrading, and to provide the
// upgraded form of the intrinsic. We should perhaps have two separate
// functions for this.
return 0;
}
// UpgradeIntrinsicCall - Upgrade a call to an old intrinsic to be a call the
// upgraded intrinsic. All argument and return casting must be provided in
// order to seamlessly integrate with existing context.
void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
assert(NewFn && "Cannot upgrade an intrinsic call without a new function.");
Function *F = CI->getCalledFunction();
assert(F && "CallInst has no function associated with it.");
const FunctionType *FTy = F->getFunctionType();
const FunctionType *NewFnTy = NewFn->getFunctionType();
switch(NewFn->getIntrinsicID()) {
default: assert(0 && "Unknown function for CallInst upgrade.");
case Intrinsic::ctlz:
case Intrinsic::ctpop:
case Intrinsic::cttz:
// Build a small vector of the 1..(N-1) operands, which are the
// parameters.
SmallVector<Value*, 8> Operands(CI->op_begin()+1, CI->op_end());
// Construct a new CallInst
CallInst *NewCI = new CallInst(NewFn, Operands.begin(), Operands.end(),
"upgraded."+CI->getName(), CI);
NewCI->setTailCall(CI->isTailCall());
NewCI->setCallingConv(CI->getCallingConv());
// Handle any uses of the old CallInst.
if (!CI->use_empty()) {
// Check for sign extend parameter attributes on the return values.
bool SrcSExt = NewFnTy->getParamAttrs() &&
NewFnTy->getParamAttrs()->paramHasAttr(0,ParamAttr::SExt);
bool DestSExt = FTy->getParamAttrs() &&
FTy->getParamAttrs()->paramHasAttr(0,ParamAttr::SExt);
// Construct an appropriate cast from the new return type to the old.
CastInst *RetCast = CastInst::create(
CastInst::getCastOpcode(NewCI, SrcSExt,
F->getReturnType(),
DestSExt),
NewCI, F->getReturnType(),
NewCI->getName(), CI);
NewCI->moveBefore(RetCast);
// Replace all uses of the old call with the new cast which has the
// correct type.
CI->replaceAllUsesWith(RetCast);
}
// Clean up the old call now that it has been completely upgraded.
CI->eraseFromParent();
break;
}
}
// This tests each Function to determine if it needs upgrading. When we find
// one we are interested in, we then upgrade all calls to reflect the new
// function.
void llvm::UpgradeCallsToIntrinsic(Function* F) {
assert(F && "Illegal attempt to upgrade a non-existent intrinsic.");
// Upgrade the function and check if it is a totaly new function.
if (Function* NewFn = UpgradeIntrinsicFunction(F)) {
if (NewFn != F) {
// Replace all uses to the old function with the new one if necessary.
for (Value::use_iterator UI = F->use_begin(), UE = F->use_end();
UI != UE; ) {
if (CallInst* CI = dyn_cast<CallInst>(*UI++))
UpgradeIntrinsicCall(CI, NewFn);
}
// Remove old function, no longer used, from the module.
F->eraseFromParent();
}
}
}
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