llvm-project/llvm/lib/VMCore/AutoUpgrade.cpp

134 lines
4.4 KiB
C++

//===-- AutoUpgrade.cpp - Implement auto-upgrade helper functions ---------===//
//
// 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 auto-upgrade helper functions
//
//===----------------------------------------------------------------------===//
#include "llvm/AutoUpgrade.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Instruction.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/IRBuilder.h"
#include <cstring>
using namespace llvm;
static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
assert(F && "Illegal to upgrade a non-existent Function.");
// Quickly eliminate it, if it's not a candidate.
StringRef Name = F->getName();
if (Name.size() <= 8 || !Name.startswith("llvm."))
return false;
Name = Name.substr(5); // Strip off "llvm."
switch (Name[0]) {
default: break;
case 'c': {
if (Name.startswith("ctlz.") && F->arg_size() == 1) {
F->setName(Name + ".old");
NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::ctlz,
F->arg_begin()->getType());
return true;
}
if (Name.startswith("cttz.") && F->arg_size() == 1) {
F->setName(Name + ".old");
NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::cttz,
F->arg_begin()->getType());
return true;
}
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 false;
}
bool llvm::UpgradeIntrinsicFunction(Function *F, Function *&NewFn) {
NewFn = 0;
bool Upgraded = UpgradeIntrinsicFunction1(F, NewFn);
// Upgrade intrinsic attributes. This does not change the function.
if (NewFn)
F = NewFn;
if (unsigned id = F->getIntrinsicID())
F->setAttributes(Intrinsic::getAttributes((Intrinsic::ID)id));
return Upgraded;
}
bool llvm::UpgradeGlobalVariable(GlobalVariable *GV) {
// Nothing to do yet.
return false;
}
// 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(CI->getCalledFunction() && "Intrinsic call is not direct?");
if (!NewFn) return;
LLVMContext &C = CI->getContext();
IRBuilder<> Builder(C);
Builder.SetInsertPoint(CI->getParent(), CI);
switch (NewFn->getIntrinsicID()) {
default:
llvm_unreachable("Unknown function for CallInst upgrade.");
case Intrinsic::ctlz:
case Intrinsic::cttz:
assert(CI->getNumArgOperands() == 1 &&
"Mismatch between function args and call args");
StringRef Name = CI->getName();
CI->setName(Name + ".old");
CI->replaceAllUsesWith(Builder.CreateCall2(NewFn, CI->getArgOperand(0),
Builder.getFalse(), Name));
CI->eraseFromParent();
return;
}
}
// 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.
Function *NewFn;
if (UpgradeIntrinsicFunction(F, NewFn)) {
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();
}
}
}