-//===- ChangeAllocations.cpp - Modify %malloc & %free calls -----------------=//
+//===- RaiseAllocations.cpp - Convert @malloc & @free calls to insts ------===//
//
-// 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 LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the RaiseAllocations pass which convert malloc and free
+// calls to malloc and free instructions.
//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/ChangeAllocations.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Module.h"
-#include "llvm/Function.h"
+#define DEBUG_TYPE "raiseallocs"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
+#include "llvm/Module.h"
+#include "llvm/Instructions.h"
#include "llvm/Pass.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/Statistic.h"
+#include <algorithm>
+using namespace llvm;
-namespace {
+STATISTIC(NumRaised, "Number of allocations raised");
-// 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) {}
-
- const char *getPassName() const { return "Raise Allocations"; }
-
- // doPassInitialization - For the raise allocations pass, this finds a
- // declaration for malloc and free if they exist.
- //
- bool doInitialization(Module *M);
-
- // runOnBasicBlock - This method does the actual work of converting
- // instructions over, assuming that the pass has already been initialized.
+namespace {
+ // RaiseAllocations - Turn @malloc and @free calls into the appropriate
+ // instruction.
//
- bool runOnBasicBlock(BasicBlock *BB);
-};
-
+ class VISIBILITY_HIDDEN RaiseAllocations : public ModulePass {
+ Function *MallocFunc; // Functions in the module we are processing
+ Function *FreeFunc; // Initialized by doPassInitializationVirt
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ RaiseAllocations()
+ : ModulePass((intptr_t)&ID), MallocFunc(0), FreeFunc(0) {}
+
+ // doPassInitialization - For the raise allocations pass, this finds a
+ // declaration for malloc and free if they exist.
+ //
+ void doInitialization(Module &M);
+
+ // run - This method does the actual work of converting instructions over.
+ //
+ bool runOnModule(Module &M);
+ };
+
+ char RaiseAllocations::ID = 0;
+ RegisterPass<RaiseAllocations>
+ X("raiseallocs", "Raise allocations from calls to instructions");
} // end anonymous namespace
// createRaiseAllocationsPass - The interface to this file...
-Pass *createRaiseAllocationsPass() {
+ModulePass *llvm::createRaiseAllocationsPass() {
return new RaiseAllocations();
}
-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),
- std::vector<const Type*>(1, Type::UIntTy), false);
-
- const FunctionType *FreeType = // Get the type for free
- FunctionType::get(Type::VoidTy,
- std::vector<const Type*>(1, PointerType::get(Type::SByteTy)),
- 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.
+//
+void RaiseAllocations::doInitialization(Module &M) {
+
+ // Get Malloc and free prototypes if they exist!
+ MallocFunc = M.getFunction("malloc");
+ if (MallocFunc) {
+ const FunctionType* TyWeHave = MallocFunc->getFunctionType();
+
+ // Get the expected prototype for malloc
+ const FunctionType *Malloc1Type =
+ FunctionType::get(PointerType::getUnqual(Type::Int8Ty),
+ std::vector<const Type*>(1, Type::Int64Ty), false);
+
+ // Chck to see if we got the expected malloc
+ if (TyWeHave != Malloc1Type) {
+ // Check to see if the prototype is wrong, giving us sbyte*(uint) * malloc
+ // This handles the common declaration of: 'void *malloc(unsigned);'
+ const FunctionType *Malloc2Type =
+ FunctionType::get(PointerType::getUnqual(Type::Int8Ty),
+ std::vector<const Type*>(1, Type::Int32Ty), false);
+ if (TyWeHave != Malloc2Type) {
+ // Check to see if the prototype is missing, giving us
+ // sbyte*(...) * malloc
+ // This handles the common declaration of: 'void *malloc();'
+ const FunctionType *Malloc3Type =
+ FunctionType::get(PointerType::getUnqual(Type::Int8Ty),
+ std::vector<const Type*>(), true);
+ if (TyWeHave != Malloc3Type)
+ // Give up
+ MallocFunc = 0;
+ }
+ }
+ }
- MallocFunc = M->getFunction("malloc", MallocType);
- FreeFunc = M->getFunction("free" , FreeType);
+ FreeFunc = M.getFunction("free");
+ if (FreeFunc) {
+ const FunctionType* TyWeHave = FreeFunc->getFunctionType();
+
+ // Get the expected prototype for void free(i8*)
+ const FunctionType *Free1Type = FunctionType::get(Type::VoidTy,
+ std::vector<const Type*>(1, PointerType::getUnqual(Type::Int8Ty)), false);
+
+ if (TyWeHave != Free1Type) {
+ // Check to see if the prototype was forgotten, giving us
+ // void (...) * free
+ // This handles the common forward declaration of: 'void free();'
+ const FunctionType* Free2Type = FunctionType::get(Type::VoidTy,
+ std::vector<const Type*>(),true);
+
+ if (TyWeHave != Free2Type) {
+ // One last try, check to see if we can find free as
+ // int (...)* free. This handles the case where NOTHING was declared.
+ const FunctionType* Free3Type = FunctionType::get(Type::Int32Ty,
+ std::vector<const Type*>(),true);
+
+ if (TyWeHave != Free3Type) {
+ // Give up.
+ FreeFunc = 0;
+ }
+ }
+ }
+ }
// Don't mess with locally defined versions of these functions...
- if (MallocFunc && !MallocFunc->isExternal()) MallocFunc = 0;
- if (FreeFunc && !FreeFunc->isExternal()) FreeFunc = 0;
- return false;
+ if (MallocFunc && !MallocFunc->isDeclaration()) MallocFunc = 0;
+ if (FreeFunc && !FreeFunc->isDeclaration()) FreeFunc = 0;
}
-// doOneCleanupPass - Do one pass over the input method, fixing stuff up.
+// run - Transform calls into instructions...
//
-bool RaiseAllocations::runOnBasicBlock(BasicBlock *BB) {
+bool RaiseAllocations::runOnModule(Module &M) {
+ // Find the malloc/free prototypes...
+ doInitialization(M);
+
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
+
+ // First, process all of the malloc calls...
+ if (MallocFunc) {
+ std::vector<User*> Users(MallocFunc->use_begin(), MallocFunc->use_end());
+ std::vector<Value*> EqPointers; // Values equal to MallocFunc
+ while (!Users.empty()) {
+ User *U = Users.back();
+ Users.pop_back();
+
+ if (Instruction *I = dyn_cast<Instruction>(U)) {
+ CallSite CS = CallSite::get(I);
+ if (CS.getInstruction() && !CS.arg_empty() &&
+ (CS.getCalledFunction() == MallocFunc ||
+ std::find(EqPointers.begin(), EqPointers.end(),
+ CS.getCalledValue()) != EqPointers.end())) {
+
+ Value *Source = *CS.arg_begin();
+
+ // If no prototype was provided for malloc, we may need to cast the
+ // source size.
+ if (Source->getType() != Type::Int32Ty)
+ Source =
+ CastInst::createIntegerCast(Source, Type::Int32Ty, false/*ZExt*/,
+ "MallocAmtCast", I);
+
+ MallocInst *MI = new MallocInst(Type::Int8Ty, Source, "", I);
+ MI->takeName(I);
+ I->replaceAllUsesWith(MI);
+
+ // If the old instruction was an invoke, add an unconditional branch
+ // before the invoke, which will become the new terminator.
+ if (InvokeInst *II = dyn_cast<InvokeInst>(I))
+ new BranchInst(II->getNormalDest(), I);
+
+ // Delete the old call site
+ MI->getParent()->getInstList().erase(I);
+ Changed = true;
+ ++NumRaised;
+ }
+ } else if (GlobalValue *GV = dyn_cast<GlobalValue>(U)) {
+ Users.insert(Users.end(), GV->use_begin(), GV->use_end());
+ EqPointers.push_back(GV);
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
+ if (CE->isCast()) {
+ Users.insert(Users.end(), CE->use_begin(), CE->use_end());
+ EqPointers.push_back(CE);
+ }
}
}
+ }
- ++BI;
+ // Next, process all free calls...
+ if (FreeFunc) {
+ std::vector<User*> Users(FreeFunc->use_begin(), FreeFunc->use_end());
+ std::vector<Value*> EqPointers; // Values equal to FreeFunc
+
+ while (!Users.empty()) {
+ User *U = Users.back();
+ Users.pop_back();
+
+ if (Instruction *I = dyn_cast<Instruction>(U)) {
+ if (isa<InvokeInst>(I))
+ continue;
+ CallSite CS = CallSite::get(I);
+ if (CS.getInstruction() && !CS.arg_empty() &&
+ (CS.getCalledFunction() == FreeFunc ||
+ std::find(EqPointers.begin(), EqPointers.end(),
+ CS.getCalledValue()) != EqPointers.end())) {
+
+ // If no prototype was provided for free, we may need to cast the
+ // source pointer. This should be really uncommon, but it's necessary
+ // just in case we are dealing with weird code like this:
+ // free((long)ptr);
+ //
+ Value *Source = *CS.arg_begin();
+ if (!isa<PointerType>(Source->getType()))
+ Source = new IntToPtrInst(Source,
+ PointerType::getUnqual(Type::Int8Ty),
+ "FreePtrCast", I);
+ new FreeInst(Source, I);
+
+ // If the old instruction was an invoke, add an unconditional branch
+ // before the invoke, which will become the new terminator.
+ if (InvokeInst *II = dyn_cast<InvokeInst>(I))
+ new BranchInst(II->getNormalDest(), I);
+
+ // Delete the old call site
+ if (I->getType() != Type::VoidTy)
+ I->replaceAllUsesWith(UndefValue::get(I->getType()));
+ I->eraseFromParent();
+ Changed = true;
+ ++NumRaised;
+ }
+ } else if (GlobalValue *GV = dyn_cast<GlobalValue>(U)) {
+ Users.insert(Users.end(), GV->use_begin(), GV->use_end());
+ EqPointers.push_back(GV);
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
+ if (CE->isCast()) {
+ Users.insert(Users.end(), CE->use_begin(), CE->use_end());
+ EqPointers.push_back(CE);
+ }
+ }
+ }
}
return Changed;
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