-//===- llvm/Transforms/LowerAllocations.h - Remove Malloc & Free Insts ------=//
+//===- ChangeAllocations.cpp - Modify %malloc & %free calls -----------------=//
//
-// This file implements a pass that lowers malloc and free instructions to
-// calls to %malloc & %free functions. This transformation is a target
-// dependant tranformation because we depend on the size of data types and
-// alignment constraints.
+// 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.
//
//===----------------------------------------------------------------------===//
#include "llvm/iOther.h"
#include "llvm/SymbolTable.h"
#include "llvm/ConstantVals.h"
+#include "TransformInternals.h"
using std::vector;
Changed = true;
}
- return Changed; // Always successful
+ return Changed;
}
-// runOnMethod - This method does the actual work of converting
+// runOnBasicBlock - This method does the actual work of converting
// instructions over, assuming that the pass has already been initialized.
//
-bool LowerAllocations::runOnMethod(Method *M) {
+bool LowerAllocations::runOnBasicBlock(BasicBlock *BB) {
bool Changed = false;
- assert(MallocMeth && FreeMeth && M && "Pass not initialized!");
+ assert(MallocMeth && FreeMeth && BB && "Pass not initialized!");
// Loop over all of the instructions, looking for malloc or free instructions
- for (Method::iterator BBI = M->begin(), BBE = M->end(); BBI != BBE; ++BBI) {
- BasicBlock *BB = *BBI;
- 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...
+ 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();
-
- // Get the number of bytes to be allocated for one element of the
- // requested type...
- unsigned Size = DataLayout.getTypeSize(AllocTy);
-
- // malloc(type) becomes sbyte *malloc(constint)
- Value *MallocArg = ConstantUInt::get(Type::UIntTy, Size);
- if (MI->getNumOperands() && Size == 1) {
- MallocArg = MI->getOperand(0); // Operand * 1 = Operand
- } else if (MI->getNumOperands()) {
- // 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));
- }
-
- // Create the call to Malloc...
- CallInst *MCall = new CallInst(MallocMeth,
- vector<Value*>(1, MallocArg));
- BBIL.insert(BBIL.begin()+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);
-
- // 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);
+ const Type *AllocTy =cast<PointerType>(MI->getType())->getElementType();
+
+ // Get the number of bytes to be allocated for one element of the
+ // requested type...
+ unsigned Size = DataLayout.getTypeSize(AllocTy);
+
+ // malloc(type) becomes sbyte *malloc(constint)
+ Value *MallocArg = ConstantUInt::get(Type::UIntTy, Size);
+ if (MI->getNumOperands() && Size == 1) {
+ MallocArg = MI->getOperand(0); // Operand * 1 = Operand
+ } else if (MI->getNumOperands()) {
+ // 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));
+ }
+
+ // Create the call to Malloc...
+ CallInst *MCall = new CallInst(MallocMeth,
+ vector<Value*>(1, MallocArg));
+ BBIL.insert(BBIL.begin()+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);
+
+ // 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);
+
+ // 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);
+
+ // Insert a call to the free function...
+ CallInst *FCall = new CallInst(FreeMeth,
+ vector<Value*>(1, MCast));
+ BBIL.insert(BBIL.begin()+i+1, FCall);
+
+ // Delete the old free instruction
+ delete FI;
+ Changed = true;
+ }
+ }
- // 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);
+ return Changed;
+}
- // Insert a call to the free function...
- CallInst *FCall = new CallInst(FreeMeth,
- vector<Value*>(1, MCast));
- BBIL.insert(BBIL.begin()+i+1, FCall);
+bool RaiseAllocations::doInitialization(Module *M) {
+ SymbolTable *ST = M->getSymbolTable();
+ if (!ST) return false;
+
+ // 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 PointerType *MallocType = // Get the type for malloc
+ PointerType::get(MethodType::get(PointerType::get(Type::SByteTy),
+ vector<const Type*>(1, Type::UIntTy), false));
+ MallocMeth = cast_or_null<Method>(ST->lookup(MallocType, "malloc"));
+ if (MallocMeth && !MallocMeth->isExternal())
+ MallocMeth = 0; // Don't mess with locally defined versions of the fn
+
+ const PointerType *FreeType = // Get the type for free
+ PointerType::get(MethodType::get(Type::VoidTy,
+ vector<const Type*>(1, PointerType::get(Type::SByteTy)), false));
+ FreeMeth = cast_or_null<Method>(ST->lookup(FreeType, "free"));
+ if (FreeMeth && !FreeMeth->isExternal())
+ FreeMeth = 0; // Don't mess with locally defined versions of the fn
+
+ return false;
+}
- // Delete the old free instruction
- delete FI;
+// 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() == MallocMeth) { // Replace call to malloc?
+ const Type *PtrSByte = PointerType::get(Type::SByteTy);
+ MallocInst *MallocI = new MallocInst(PtrSByte, CI->getOperand(1),
+ CI->getName());
+ CI->setName("");
+ BI = BIL.insert(BI, MallocI)+1;
+ ReplaceInstWithInst(BIL, BI, new CastInst(MallocI, PtrSByte));
Changed = true;
+ continue; // Skip the ++BI
+ } else if (CI->getCalledValue() == FreeMeth) { // Replace call to free?
+ ReplaceInstWithInst(BIL, BI, new FreeInst(CI->getOperand(1)));
+ Changed = true;
+ continue; // Skip the ++BI
}
}
+
+ ++BI;
}
return Changed;
}
-
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