2002-05-07 19:04:39 +00:00
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//===- RaiseAllocations.cpp - Convert %malloc & %free calls to insts ------===//
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2005-04-21 23:48:37 +00:00
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//
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2003-10-20 19:43:21 +00:00
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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2005-04-21 23:48:37 +00:00
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//
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2003-10-20 19:43:21 +00:00
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//===----------------------------------------------------------------------===//
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2002-05-07 19:02:48 +00:00
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//
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2002-05-07 19:04:39 +00:00
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// This file defines the RaiseAllocations pass which convert malloc and free
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// calls to malloc and free instructions.
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2002-05-07 19:02:48 +00:00
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//
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//===----------------------------------------------------------------------===//
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2003-09-01 03:14:56 +00:00
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#include "llvm/Transforms/IPO.h"
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2003-12-07 01:42:08 +00:00
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#include "llvm/Constants.h"
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2002-05-07 19:02:48 +00:00
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#include "llvm/DerivedTypes.h"
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2003-12-07 01:42:08 +00:00
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#include "llvm/Module.h"
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2004-07-29 17:30:56 +00:00
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#include "llvm/Instructions.h"
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2002-05-07 19:02:48 +00:00
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#include "llvm/Pass.h"
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2003-09-01 03:14:56 +00:00
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#include "llvm/Support/CallSite.h"
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2004-09-01 22:55:40 +00:00
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#include "llvm/ADT/Statistic.h"
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2003-11-21 21:54:22 +00:00
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using namespace llvm;
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2003-11-11 22:41:34 +00:00
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2002-05-07 19:02:48 +00:00
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namespace {
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2006-12-06 17:46:33 +00:00
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Statistic NumRaised("raiseallocs", "Number of allocations raised");
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2002-05-07 19:02:48 +00:00
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2002-10-01 22:38:41 +00:00
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// RaiseAllocations - Turn %malloc and %free calls into the appropriate
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// instruction.
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2002-05-07 19:02:48 +00:00
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//
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2004-09-20 04:48:05 +00:00
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class RaiseAllocations : public ModulePass {
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2002-10-01 22:38:41 +00:00
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Function *MallocFunc; // Functions in the module we are processing
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Function *FreeFunc; // Initialized by doPassInitializationVirt
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public:
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RaiseAllocations() : MallocFunc(0), FreeFunc(0) {}
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2005-04-21 23:48:37 +00:00
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2002-10-01 22:38:41 +00:00
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// doPassInitialization - For the raise allocations pass, this finds a
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// declaration for malloc and free if they exist.
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//
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2003-09-01 03:14:56 +00:00
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void doInitialization(Module &M);
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2005-04-21 23:48:37 +00:00
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2003-09-01 03:14:56 +00:00
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// run - This method does the actual work of converting instructions over.
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2002-10-01 22:38:41 +00:00
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//
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2004-09-20 04:48:05 +00:00
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bool runOnModule(Module &M);
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2002-10-01 22:38:41 +00:00
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};
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2005-04-21 23:48:37 +00:00
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2006-08-27 22:42:52 +00:00
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RegisterPass<RaiseAllocations>
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2002-07-26 21:12:46 +00:00
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X("raiseallocs", "Raise allocations from calls to instructions");
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2002-05-07 19:02:48 +00:00
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} // end anonymous namespace
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// createRaiseAllocationsPass - The interface to this file...
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2004-09-20 04:48:05 +00:00
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ModulePass *llvm::createRaiseAllocationsPass() {
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2002-05-07 19:02:48 +00:00
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return new RaiseAllocations();
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}
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2003-09-01 03:14:56 +00:00
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// If the module has a symbol table, they might be referring to the malloc and
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// free functions. If this is the case, grab the method pointers that the
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// module is using.
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//
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// Lookup %malloc and %free in the symbol table, for later use. If they don't
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// exist, or are not external, we do not worry about converting calls to that
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// function into the appropriate instruction.
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//
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void RaiseAllocations::doInitialization(Module &M) {
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2002-05-07 19:02:48 +00:00
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const FunctionType *MallocType = // Get the type for malloc
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FunctionType::get(PointerType::get(Type::SByteTy),
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2002-07-18 00:18:01 +00:00
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std::vector<const Type*>(1, Type::ULongTy), false);
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2002-05-07 19:02:48 +00:00
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const FunctionType *FreeType = // Get the type for free
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FunctionType::get(Type::VoidTy,
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std::vector<const Type*>(1, PointerType::get(Type::SByteTy)),
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false);
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2002-07-18 00:18:01 +00:00
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// Get Malloc and free prototypes if they exist!
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2002-06-25 16:13:24 +00:00
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MallocFunc = M.getFunction("malloc", MallocType);
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FreeFunc = M.getFunction("free" , FreeType);
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2002-05-07 19:02:48 +00:00
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2002-07-18 00:18:01 +00:00
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// Check to see if the prototype is wrong, giving us sbyte*(uint) * malloc
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// This handles the common declaration of: 'void *malloc(unsigned);'
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if (MallocFunc == 0) {
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MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
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std::vector<const Type*>(1, Type::UIntTy), false);
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MallocFunc = M.getFunction("malloc", MallocType);
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}
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2002-05-24 20:29:18 +00:00
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// Check to see if the prototype is missing, giving us sbyte*(...) * malloc
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2002-07-18 00:18:01 +00:00
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// This handles the common declaration of: 'void *malloc();'
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2002-05-24 20:29:18 +00:00
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if (MallocFunc == 0) {
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MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
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std::vector<const Type*>(), true);
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2002-06-25 16:13:24 +00:00
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MallocFunc = M.getFunction("malloc", MallocType);
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2002-05-24 20:29:18 +00:00
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}
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// Check to see if the prototype was forgotten, giving us void (...) * free
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// This handles the common forward declaration of: 'void free();'
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if (FreeFunc == 0) {
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FreeType = FunctionType::get(Type::VoidTy, std::vector<const Type*>(),true);
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2002-06-25 16:13:24 +00:00
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FreeFunc = M.getFunction("free", FreeType);
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2002-05-24 20:29:18 +00:00
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}
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2003-08-11 15:05:08 +00:00
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// One last try, check to see if we can find free as 'int (...)* free'. This
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// handles the case where NOTHING was declared.
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if (FreeFunc == 0) {
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FreeType = FunctionType::get(Type::IntTy, std::vector<const Type*>(),true);
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FreeFunc = M.getFunction("free", FreeType);
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}
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2002-05-07 19:02:48 +00:00
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// Don't mess with locally defined versions of these functions...
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if (MallocFunc && !MallocFunc->isExternal()) MallocFunc = 0;
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if (FreeFunc && !FreeFunc->isExternal()) FreeFunc = 0;
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}
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2003-09-01 03:14:56 +00:00
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// run - Transform calls into instructions...
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2002-05-07 19:02:48 +00:00
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//
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2004-09-20 04:48:05 +00:00
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bool RaiseAllocations::runOnModule(Module &M) {
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2003-09-01 03:14:56 +00:00
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// Find the malloc/free prototypes...
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doInitialization(M);
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2002-05-07 19:02:48 +00:00
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bool Changed = false;
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2003-09-01 03:14:56 +00:00
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// First, process all of the malloc calls...
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if (MallocFunc) {
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std::vector<User*> Users(MallocFunc->use_begin(), MallocFunc->use_end());
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2003-12-07 01:42:08 +00:00
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std::vector<Value*> EqPointers; // Values equal to MallocFunc
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2003-09-01 03:14:56 +00:00
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while (!Users.empty()) {
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2003-12-07 01:42:08 +00:00
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User *U = Users.back();
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Users.pop_back();
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if (Instruction *I = dyn_cast<Instruction>(U)) {
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2003-09-01 03:14:56 +00:00
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CallSite CS = CallSite::get(I);
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2003-12-07 01:42:08 +00:00
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if (CS.getInstruction() && CS.arg_begin() != CS.arg_end() &&
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(CS.getCalledFunction() == MallocFunc ||
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std::find(EqPointers.begin(), EqPointers.end(),
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CS.getCalledValue()) != EqPointers.end())) {
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2005-04-21 23:48:37 +00:00
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2003-09-01 03:14:56 +00:00
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Value *Source = *CS.arg_begin();
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2005-04-21 23:48:37 +00:00
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2003-09-01 03:14:56 +00:00
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// If no prototype was provided for malloc, we may need to cast the
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// source size.
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if (Source->getType() != Type::UIntTy)
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2006-11-27 01:05:10 +00:00
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Source =
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CastInst::createInferredCast(Source, Type::UIntTy,
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"MallocAmtCast", I);
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2005-04-21 23:48:37 +00:00
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2003-09-01 03:14:56 +00:00
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std::string Name(I->getName()); I->setName("");
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MallocInst *MI = new MallocInst(Type::SByteTy, Source, Name, I);
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I->replaceAllUsesWith(MI);
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2003-09-16 19:42:21 +00:00
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// If the old instruction was an invoke, add an unconditional branch
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// before the invoke, which will become the new terminator.
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if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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new BranchInst(II->getNormalDest(), I);
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// Delete the old call site
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2003-09-01 03:14:56 +00:00
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MI->getParent()->getInstList().erase(I);
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Changed = true;
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++NumRaised;
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}
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2004-07-18 00:44:37 +00:00
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} else if (GlobalValue *GV = dyn_cast<GlobalValue>(U)) {
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Users.insert(Users.end(), GV->use_begin(), GV->use_end());
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EqPointers.push_back(GV);
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2003-12-07 01:42:08 +00:00
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} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
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2006-11-27 01:05:10 +00:00
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if (CE->isCast()) {
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2003-12-07 01:42:08 +00:00
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Users.insert(Users.end(), CE->use_begin(), CE->use_end());
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EqPointers.push_back(CE);
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}
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2003-09-01 03:14:56 +00:00
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}
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}
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}
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// Next, process all free calls...
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if (FreeFunc) {
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std::vector<User*> Users(FreeFunc->use_begin(), FreeFunc->use_end());
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2003-12-07 01:42:08 +00:00
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std::vector<Value*> EqPointers; // Values equal to FreeFunc
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2003-09-01 03:14:56 +00:00
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while (!Users.empty()) {
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2003-12-07 01:42:08 +00:00
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User *U = Users.back();
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Users.pop_back();
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if (Instruction *I = dyn_cast<Instruction>(U)) {
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2003-09-01 03:14:56 +00:00
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CallSite CS = CallSite::get(I);
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2003-12-07 01:42:08 +00:00
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if (CS.getInstruction() && CS.arg_begin() != CS.arg_end() &&
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(CS.getCalledFunction() == FreeFunc ||
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std::find(EqPointers.begin(), EqPointers.end(),
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CS.getCalledValue()) != EqPointers.end())) {
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2005-04-21 23:48:37 +00:00
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2003-09-01 03:14:56 +00:00
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// If no prototype was provided for free, we may need to cast the
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// source pointer. This should be really uncommon, but it's necessary
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2005-02-27 06:18:25 +00:00
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// just in case we are dealing with weird code like this:
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2003-09-01 03:14:56 +00:00
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// free((long)ptr);
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//
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Value *Source = *CS.arg_begin();
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if (!isa<PointerType>(Source->getType()))
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2006-11-27 01:05:10 +00:00
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Source = CastInst::createInferredCast(
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Source, PointerType::get(Type::SByteTy), "FreePtrCast", I);
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2003-09-01 03:14:56 +00:00
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new FreeInst(Source, I);
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2003-09-16 19:42:21 +00:00
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// If the old instruction was an invoke, add an unconditional branch
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// before the invoke, which will become the new terminator.
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if (InvokeInst *II = dyn_cast<InvokeInst>(I))
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new BranchInst(II->getNormalDest(), I);
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// Delete the old call site
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2004-11-09 05:10:56 +00:00
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if (I->getType() != Type::VoidTy)
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I->replaceAllUsesWith(UndefValue::get(I->getType()));
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I->eraseFromParent();
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2003-09-01 03:14:56 +00:00
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Changed = true;
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++NumRaised;
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}
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2004-07-18 00:44:37 +00:00
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} else if (GlobalValue *GV = dyn_cast<GlobalValue>(U)) {
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Users.insert(Users.end(), GV->use_begin(), GV->use_end());
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EqPointers.push_back(GV);
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2003-12-07 01:42:08 +00:00
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} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
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2006-11-27 01:05:10 +00:00
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if (CE->isCast()) {
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2003-12-07 01:42:08 +00:00
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Users.insert(Users.end(), CE->use_begin(), CE->use_end());
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EqPointers.push_back(CE);
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}
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2002-05-07 19:02:48 +00:00
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}
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}
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}
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return Changed;
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}
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