//===- LowerAllocations.cpp - Reduce malloc & free insts to calls ---------===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// The LowerAllocations transformation is a target-dependent tranformation
//
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "lowerallocs"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
+#include "llvm/Instructions.h"
#include "llvm/Constants.h"
#include "llvm/Pass.h"
-#include "Support/Statistic.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Support/Compiler.h"
using namespace llvm;
-namespace {
- Statistic<> NumLowered("lowerallocs", "Number of allocations lowered");
+STATISTIC(NumLowered, "Number of allocations lowered");
+namespace {
/// LowerAllocations - Turn malloc and free instructions into %malloc and
/// %free calls.
///
- class LowerAllocations : public BasicBlockPass {
- Function *MallocFunc; // Functions in the module we are processing
- Function *FreeFunc; // Initialized by doInitialization
+ class VISIBILITY_HIDDEN LowerAllocations : public BasicBlockPass {
+ Constant *MallocFunc; // Functions in the module we are processing
+ Constant *FreeFunc; // Initialized by doInitialization
+ bool LowerMallocArgToInteger;
public:
- LowerAllocations() : MallocFunc(0), FreeFunc(0) {}
+ static char ID; // Pass ID, replacement for typeid
+ explicit LowerAllocations(bool LowerToInt = false)
+ : BasicBlockPass((intptr_t)&ID), MallocFunc(0), FreeFunc(0),
+ LowerMallocArgToInteger(LowerToInt) {}
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<TargetData>();
+ AU.setPreservesCFG();
+
+ // This is a cluster of orthogonal Transforms:
+ AU.addPreserved<UnifyFunctionExitNodes>();
+ AU.addPreservedID(PromoteMemoryToRegisterID);
+ AU.addPreservedID(LowerSelectID);
+ AU.addPreservedID(LowerSwitchID);
+ AU.addPreservedID(LowerInvokePassID);
+ }
/// doPassInitialization - For the lower allocations pass, this ensures that
/// a module contains a declaration for a malloc and a free function.
///
bool doInitialization(Module &M);
-
+
+ virtual bool doInitialization(Function &F) {
+ return BasicBlockPass::doInitialization(F);
+ }
+
/// runOnBasicBlock - This method does the actual work of converting
/// instructions over, assuming that the pass has already been initialized.
///
bool runOnBasicBlock(BasicBlock &BB);
};
- RegisterOpt<LowerAllocations>
+ char LowerAllocations::ID = 0;
+ RegisterPass<LowerAllocations>
X("lowerallocs", "Lower allocations from instructions to calls");
}
+// Publically exposed interface to pass...
+const PassInfo *llvm::LowerAllocationsID = X.getPassInfo();
// createLowerAllocationsPass - Interface to this file...
-FunctionPass *llvm::createLowerAllocationsPass() {
- return new LowerAllocations();
+Pass *llvm::createLowerAllocationsPass(bool LowerMallocArgToInteger) {
+ return new LowerAllocations(LowerMallocArgToInteger);
}
// This function is always successful.
//
bool LowerAllocations::doInitialization(Module &M) {
- const Type *SBPTy = PointerType::get(Type::SByteTy);
- MallocFunc = M.getNamedFunction("malloc");
- FreeFunc = M.getNamedFunction("free");
-
- if (MallocFunc == 0)
- MallocFunc = M.getOrInsertFunction("malloc", SBPTy, Type::UIntTy, 0);
- if (FreeFunc == 0)
- FreeFunc = M.getOrInsertFunction("free" , Type::VoidTy, SBPTy, 0);
-
+ const Type *BPTy = PointerType::getUnqual(Type::Int8Ty);
+ // Prototype malloc as "char* malloc(...)", because we don't know in
+ // doInitialization whether size_t is int or long.
+ FunctionType *FT = FunctionType::get(BPTy, std::vector<const Type*>(), true);
+ MallocFunc = M.getOrInsertFunction("malloc", FT);
+ FreeFunc = M.getOrInsertFunction("free" , Type::VoidTy, BPTy, (Type *)0);
return true;
}
-static Constant *getSizeof(const Type *Ty) {
- Constant *Ret = ConstantPointerNull::get(PointerType::get(Ty));
- std::vector<Constant*> Idx;
- Idx.push_back(ConstantUInt::get(Type::UIntTy, 1));
- Ret = ConstantExpr::getGetElementPtr(Ret, Idx);
- return ConstantExpr::getCast(Ret, Type::UIntTy);
-}
-
// runOnBasicBlock - This method does the actual work of converting
// instructions over, assuming that the pass has already been initialized.
//
BasicBlock::InstListType &BBIL = BB.getInstList();
+ const TargetData &TD = getAnalysis<TargetData>();
+ const Type *IntPtrTy = TD.getIntPtrType();
+
// Loop over all of the instructions, looking for malloc or free instructions
for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
const Type *AllocTy = MI->getType()->getElementType();
-
+
// malloc(type) becomes sbyte *malloc(size)
- Value *MallocArg = getSizeof(AllocTy);
+ Value *MallocArg;
+ if (LowerMallocArgToInteger)
+ MallocArg = ConstantInt::get(Type::Int64Ty, TD.getABITypeSize(AllocTy));
+ else
+ MallocArg = ConstantExpr::getSizeOf(AllocTy);
+ MallocArg = ConstantExpr::getTruncOrBitCast(cast<Constant>(MallocArg),
+ IntPtrTy);
+
if (MI->isArrayAllocation()) {
- if (isa<ConstantUInt>(MallocArg) &&
- cast<ConstantUInt>(MallocArg)->getValue() == 1) {
+ if (isa<ConstantInt>(MallocArg) &&
+ cast<ConstantInt>(MallocArg)->isOne()) {
MallocArg = MI->getOperand(0); // Operand * 1 = Operand
} else if (Constant *CO = dyn_cast<Constant>(MI->getOperand(0))) {
+ CO = ConstantExpr::getIntegerCast(CO, IntPtrTy, false /*ZExt*/);
MallocArg = ConstantExpr::getMul(CO, cast<Constant>(MallocArg));
} else {
+ Value *Scale = MI->getOperand(0);
+ if (Scale->getType() != IntPtrTy)
+ Scale = CastInst::createIntegerCast(Scale, IntPtrTy, false /*ZExt*/,
+ "", I);
+
// Multiply it by the array size if necessary...
- MallocArg = BinaryOperator::create(Instruction::Mul,
- MI->getOperand(0),
+ MallocArg = BinaryOperator::create(Instruction::Mul, Scale,
MallocArg, "", I);
}
}
- const FunctionType *MallocFTy = MallocFunc->getFunctionType();
- std::vector<Value*> MallocArgs;
-
- if (MallocFTy->getNumParams() > 0 || MallocFTy->isVarArg()) {
- if (MallocFTy->getNumParams() > 0 &&
- MallocFTy->getParamType(0) != Type::UIntTy)
- MallocArg = new CastInst(MallocArg, MallocFTy->getParamType(0), "",I);
- MallocArgs.push_back(MallocArg);
- }
-
- // If malloc is prototyped to take extra arguments, pass nulls.
- for (unsigned i = 1; i < MallocFTy->getNumParams(); ++i)
- MallocArgs.push_back(Constant::getNullValue(MallocFTy->getParamType(i)));
+ // Create the call to Malloc.
+ CallInst *MCall = new CallInst(MallocFunc, MallocArg, "", I);
+ MCall->setTailCall();
- // Create the call to Malloc...
- CallInst *MCall = new CallInst(MallocFunc, MallocArgs, "", I);
-
// Create a cast instruction to convert to the right type...
Value *MCast;
if (MCall->getType() != Type::VoidTy)
- MCast = new CastInst(MCall, MI->getType(), "", I);
+ MCast = new BitCastInst(MCall, MI->getType(), "", I);
else
MCast = Constant::getNullValue(MI->getType());
-
+
// Replace all uses of the old malloc inst with the cast inst
MI->replaceAllUsesWith(MCast);
I = --BBIL.erase(I); // remove and delete the malloc instr...
Changed = true;
++NumLowered;
} else if (FreeInst *FI = dyn_cast<FreeInst>(I)) {
- const FunctionType *FreeFTy = FreeFunc->getFunctionType();
- std::vector<Value*> FreeArgs;
-
- if (FreeFTy->getNumParams() > 0 || FreeFTy->isVarArg()) {
- Value *MCast = FI->getOperand(0);
- if (FreeFTy->getNumParams() > 0 &&
- FreeFTy->getParamType(0) != MCast->getType())
- MCast = new CastInst(MCast, FreeFTy->getParamType(0), "", I);
- FreeArgs.push_back(MCast);
- }
+ Value *PtrCast =
+ new BitCastInst(FI->getOperand(0),
+ PointerType::getUnqual(Type::Int8Ty), "", I);
- // If malloc is prototyped to take extra arguments, pass nulls.
- for (unsigned i = 1; i < FreeFTy->getNumParams(); ++i)
- FreeArgs.push_back(Constant::getNullValue(FreeFTy->getParamType(i)));
-
// Insert a call to the free function...
- new CallInst(FreeFunc, FreeArgs, "", I);
-
+ (new CallInst(FreeFunc, PtrCast, "", I))->setTailCall();
+
// Delete the old free instruction
I = --BBIL.erase(I);
Changed = true;
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