-//===- ChangeAllocations.cpp - Modify %malloc & %free calls -----------------=//
+//===- LowerAllocations.cpp - Reduce malloc & free insts to calls ---------===//
//
-// This file defines two passes that convert malloc and free instructions to
-// calls to and from %malloc & %free function calls. The LowerAllocations
-// transformation is a target dependant tranformation because it depends on the
-// size of data types and alignment constraints.
+// The LowerAllocations transformation is a target dependant tranformation
+// because it depends on the size of data types and alignment constraints.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/ChangeAllocations.h"
-#include "llvm/Target/TargetData.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
+#include "llvm/BasicBlock.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iMemory.h"
#include "llvm/iOther.h"
#include "llvm/Constants.h"
#include "llvm/Pass.h"
-#include "TransformInternals.h"
+#include "llvm/Target/TargetData.h"
+#include "Support/StatisticReporter.h"
+
+static Statistic<> NumLowered("lowerallocs\t- Number of allocations lowered");
using std::vector;
namespace {
const TargetData &DataLayout;
public:
- inline LowerAllocations(const TargetData &TD) : DataLayout(TD) {
+ LowerAllocations(const TargetData &TD) : DataLayout(TD) {
MallocFunc = FreeFunc = 0;
}
// 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);
+ bool doInitialization(Module &M);
// runOnBasicBlock - This method does the actual work of converting
// instructions over, assuming that the pass has already been initialized.
//
- bool runOnBasicBlock(BasicBlock *BB);
+ bool runOnBasicBlock(BasicBlock &BB);
};
+}
-// RaiseAllocations - Turn %malloc and %free calls into the appropriate
-// instruction.
-//
-class RaiseAllocations : public BasicBlockPass {
- Function *MallocFunc; // Functions in the module we are processing
- Function *FreeFunc; // Initialized by doPassInitializationVirt
-public:
- inline RaiseAllocations() : MallocFunc(0), FreeFunc(0) {}
-
- // doPassInitialization - For the raise allocations pass, this finds a
- // declaration for malloc and free if they exist.
- //
- bool doInitialization(Module *M);
+// createLowerAllocationsPass - Interface to this file...
+Pass *createLowerAllocationsPass(const TargetData &TD) {
+ return new LowerAllocations(TD);
+}
- // runOnBasicBlock - This method does the actual work of converting
- // instructions over, assuming that the pass has already been initialized.
- //
- bool runOnBasicBlock(BasicBlock *BB);
-};
+static RegisterPass<LowerAllocations>
+X("lowerallocs", "Lower allocations from instructions to calls (TD)",
+ createLowerAllocationsPass);
-} // end anonymous namespace
// doInitialization - For the lower allocations pass, this ensures that a
// module contains a declaration for a malloc and a free function.
//
// This function is always successful.
//
-bool LowerAllocations::doInitialization(Module *M) {
+bool LowerAllocations::doInitialization(Module &M) {
const FunctionType *MallocType =
FunctionType::get(PointerType::get(Type::SByteTy),
vector<const Type*>(1, Type::UIntTy), false);
vector<const Type*>(1, PointerType::get(Type::SByteTy)),
false);
- MallocFunc = M->getOrInsertFunction("malloc", MallocType);
- FreeFunc = M->getOrInsertFunction("free" , FreeType);
+ MallocFunc = M.getOrInsertFunction("malloc", MallocType);
+ FreeFunc = M.getOrInsertFunction("free" , FreeType);
- return false;
+ return true;
}
// runOnBasicBlock - This method does the actual work of converting
// instructions over, assuming that the pass has already been initialized.
//
-bool LowerAllocations::runOnBasicBlock(BasicBlock *BB) {
+bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
bool Changed = false;
- assert(MallocFunc && FreeFunc && BB && "Pass not initialized!");
+ assert(MallocFunc && FreeFunc && "Pass not initialized!");
+
+ BasicBlock::InstListType &BBIL = BB.getInstList();
// Loop over all of the instructions, looking for malloc or free instructions
- for (unsigned i = 0; i < BB->size(); ++i) {
- BasicBlock::InstListType &BBIL = BB->getInstList();
- if (MallocInst *MI = dyn_cast<MallocInst>(*(BBIL.begin()+i))) {
- BBIL.remove(BBIL.begin()+i); // remove the malloc instr...
-
- const Type *AllocTy =cast<PointerType>(MI->getType())->getElementType();
+ for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
+ if (MallocInst *MI = dyn_cast<MallocInst>(&*I)) {
+ BBIL.remove(I); // remove the malloc instr...
+
+ const Type *AllocTy = MI->getType()->getElementType();
// Get the number of bytes to be allocated for one element of the
// requested type...
// Multiply it by the array size if neccesary...
MallocArg = BinaryOperator::create(Instruction::Mul,MI->getOperand(0),
MallocArg);
- BBIL.insert(BBIL.begin()+i++, cast<Instruction>(MallocArg));
+ I = ++BBIL.insert(I, cast<Instruction>(MallocArg));
}
// Create the call to Malloc...
CallInst *MCall = new CallInst(MallocFunc,
vector<Value*>(1, MallocArg));
- BBIL.insert(BBIL.begin()+i, MCall);
+ I = BBIL.insert(I, MCall);
// Create a cast instruction to convert to the right type...
CastInst *MCast = new CastInst(MCall, MI->getType());
- BBIL.insert(BBIL.begin()+i+1, MCast);
+ I = BBIL.insert(++I, MCast);
// Replace all uses of the old malloc inst with the cast inst
MI->replaceAllUsesWith(MCast);
delete MI; // Delete the malloc inst
Changed = true;
- } else if (FreeInst *FI = dyn_cast<FreeInst>(*(BBIL.begin()+i))) {
- BBIL.remove(BB->getInstList().begin()+i);
+ ++NumLowered;
+ } else if (FreeInst *FI = dyn_cast<FreeInst>(&*I)) {
+ BBIL.remove(I);
// Cast the argument to free into a ubyte*...
CastInst *MCast = new CastInst(FI->getOperand(0),
PointerType::get(Type::UByteTy));
- BBIL.insert(BBIL.begin()+i, MCast);
+ I = ++BBIL.insert(I, MCast);
// Insert a call to the free function...
- CallInst *FCall = new CallInst(FreeFunc,
- vector<Value*>(1, MCast));
- BBIL.insert(BBIL.begin()+i+1, FCall);
+ CallInst *FCall = new CallInst(FreeFunc, vector<Value*>(1, MCast));
+ I = BBIL.insert(I, FCall);
// Delete the old free instruction
delete FI;
Changed = true;
+ ++NumLowered;
}
}
return Changed;
}
-
-bool RaiseAllocations::doInitialization(Module *M) {
- // If the module has a symbol table, they might be referring to the malloc
- // and free functions. If this is the case, grab the method pointers that
- // the module is using.
- //
- // Lookup %malloc and %free in the symbol table, for later use. If they
- // don't exist, or are not external, we do not worry about converting calls
- // to that function into the appropriate instruction.
- //
- const FunctionType *MallocType = // Get the type for malloc
- FunctionType::get(PointerType::get(Type::SByteTy),
- vector<const Type*>(1, Type::UIntTy), false);
-
- const FunctionType *FreeType = // Get the type for free
- FunctionType::get(Type::VoidTy,
- vector<const Type*>(1, PointerType::get(Type::SByteTy)),
- false);
-
- MallocFunc = M->getFunction("malloc", MallocType);
- FreeFunc = M->getFunction("free" , FreeType);
-
- // Don't mess with locally defined versions of these functions...
- if (MallocFunc && !MallocFunc->isExternal()) MallocFunc = 0;
- if (FreeFunc && !FreeFunc->isExternal()) FreeFunc = 0;
- return false;
-}
-
-// doOneCleanupPass - Do one pass over the input method, fixing stuff up.
-//
-bool RaiseAllocations::runOnBasicBlock(BasicBlock *BB) {
- bool Changed = false;
- BasicBlock::InstListType &BIL = BB->getInstList();
-
- for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
- Instruction *I = *BI;
-
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (CI->getCalledValue() == MallocFunc) { // Replace call to malloc?
- const Type *PtrSByte = PointerType::get(Type::SByteTy);
- MallocInst *MallocI = new MallocInst(PtrSByte, CI->getOperand(1),
- CI->getName());
- CI->setName("");
- ReplaceInstWithInst(BIL, BI, MallocI);
- Changed = true;
- continue; // Skip the ++BI
- } else if (CI->getCalledValue() == FreeFunc) { // Replace call to free?
- ReplaceInstWithInst(BIL, BI, new FreeInst(CI->getOperand(1)));
- Changed = true;
- continue; // Skip the ++BI
- }
- }
-
- ++BI;
- }
-
- return Changed;
-}
-
-Pass *createLowerAllocationsPass(const TargetData &TD) {
- return new LowerAllocations(TD);
-}
-Pass *createRaiseAllocationsPass() {
- return new RaiseAllocations();
-}
-
-
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