lib/Transforms/IPO/RaiseAllocations.cpp - llvm - Git at Google

 //===- RaiseAllocations.cpp - Convert %malloc & %free calls to insts ------===//
 //
 //                     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 defines the RaiseAllocations pass which convert malloc and free
 // calls to malloc and free instructions.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Transforms/IPO.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Module.h"
 #include "llvm/Instructions.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CallSite.h"
 #include "llvm/ADT/Statistic.h"
 using namespace llvm;

 namespace {
   Statistic<> NumRaised("raiseallocs", "Number of allocations raised");

   // RaiseAllocations - Turn %malloc and %free calls into the appropriate
   // instruction.
   //
   class RaiseAllocations : public ModulePass {
     Function *MallocFunc;   // Functions in the module we are processing
     Function *FreeFunc;     // Initialized by doPassInitializationVirt
   public:
     RaiseAllocations() : 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);
   };

   RegisterOpt<RaiseAllocations>
   X("raiseallocs", "Raise allocations from calls to instructions");
 }  // end anonymous namespace


 // createRaiseAllocationsPass - The interface to this file...
 ModulePass *llvm::createRaiseAllocationsPass() {
   return new RaiseAllocations();
 }


 // 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) {
   const FunctionType *MallocType =   // Get the type for malloc
     FunctionType::get(PointerType::get(Type::SByteTy),
                     std::vector<const Type*>(1, Type::ULongTy), false);

   const FunctionType *FreeType =     // Get the type for free
     FunctionType::get(Type::VoidTy,
                    std::vector<const Type*>(1, PointerType::get(Type::SByteTy)),
                       false);

   // Get Malloc and free prototypes if they exist!
   MallocFunc = M.getFunction("malloc", MallocType);
   FreeFunc   = M.getFunction("free"  , FreeType);

   // Check to see if the prototype is wrong, giving us sbyte*(uint) * malloc
   // This handles the common declaration of: 'void *malloc(unsigned);'
   if (MallocFunc == 0) {
     MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
                             std::vector<const Type*>(1, Type::UIntTy), false);
     MallocFunc = M.getFunction("malloc", MallocType);
   }

   // Check to see if the prototype is missing, giving us sbyte*(...) * malloc
   // This handles the common declaration of: 'void *malloc();'
   if (MallocFunc == 0) {
     MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
                                    std::vector<const Type*>(), true);
     MallocFunc = M.getFunction("malloc", MallocType);
   }

   // Check to see if the prototype was forgotten, giving us void (...) * free
   // This handles the common forward declaration of: 'void free();'
   if (FreeFunc == 0) {
     FreeType = FunctionType::get(Type::VoidTy, std::vector<const Type*>(),true);
     FreeFunc = M.getFunction("free", FreeType);
   }

   // One last try, check to see if we can find free as 'int (...)* free'.  This
   // handles the case where NOTHING was declared.
   if (FreeFunc == 0) {
     FreeType = FunctionType::get(Type::IntTy, std::vector<const Type*>(),true);
     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;
 }

 // run - Transform calls into instructions...
 //
 bool RaiseAllocations::runOnModule(Module &M) {
   // Find the malloc/free prototypes...
   doInitialization(M);

   bool Changed = false;

   // 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_begin() != CS.arg_end() &&
             (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::UIntTy)
             Source = new CastInst(Source, Type::UIntTy, "MallocAmtCast", I);

           std::string Name(I->getName()); I->setName("");
           MallocInst *MI = new MallocInst(Type::SByteTy, Source, Name, 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->getOpcode() == Instruction::Cast) {
           Users.insert(Users.end(), CE->use_begin(), CE->use_end());
           EqPointers.push_back(CE);
         }
       }
     }
   }

   // 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)) {
         CallSite CS = CallSite::get(I);
         if (CS.getInstruction() && CS.arg_begin() != CS.arg_end() &&
             (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 CastInst(Source, PointerType::get(Type::SByteTy),
                                   "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->getOpcode() == Instruction::Cast) {
           Users.insert(Users.end(), CE->use_begin(), CE->use_end());
           EqPointers.push_back(CE);
         }
       }
     }
   }

   return Changed;
 }
	//===- RaiseAllocations.cpp - Convert %malloc & %free calls to insts ------===//
	//
	// 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 defines the RaiseAllocations pass which convert malloc and free
	// calls to malloc and free instructions.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Transforms/IPO.h"
	#include "llvm/Constants.h"
	#include "llvm/DerivedTypes.h"
	#include "llvm/Module.h"
	#include "llvm/Instructions.h"
	#include "llvm/Pass.h"
	#include "llvm/Support/CallSite.h"
	#include "llvm/ADT/Statistic.h"
	using namespace llvm;

	namespace {
	Statistic<> NumRaised("raiseallocs", "Number of allocations raised");

	// RaiseAllocations - Turn %malloc and %free calls into the appropriate
	// instruction.
	//
	class RaiseAllocations : public ModulePass {
	Function *MallocFunc; // Functions in the module we are processing
	Function *FreeFunc; // Initialized by doPassInitializationVirt
	public:
	RaiseAllocations() : 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);
	};

	RegisterOpt<RaiseAllocations>
	X("raiseallocs", "Raise allocations from calls to instructions");
	} // end anonymous namespace


	// createRaiseAllocationsPass - The interface to this file...
	ModulePass *llvm::createRaiseAllocationsPass() {
	return new RaiseAllocations();
	}


	// 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) {
	const FunctionType *MallocType = // Get the type for malloc
	FunctionType::get(PointerType::get(Type::SByteTy),
	std::vector<const Type*>(1, Type::ULongTy), false);

	const FunctionType *FreeType = // Get the type for free
	FunctionType::get(Type::VoidTy,
	std::vector<const Type*>(1, PointerType::get(Type::SByteTy)),
	false);

	// Get Malloc and free prototypes if they exist!
	MallocFunc = M.getFunction("malloc", MallocType);
	FreeFunc = M.getFunction("free" , FreeType);

	// Check to see if the prototype is wrong, giving us sbyte(uint) malloc
	// This handles the common declaration of: 'void *malloc(unsigned);'
	if (MallocFunc == 0) {
	MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
	std::vector<const Type*>(1, Type::UIntTy), false);
	MallocFunc = M.getFunction("malloc", MallocType);
	}

	// Check to see if the prototype is missing, giving us sbyte(...) malloc
	// This handles the common declaration of: 'void *malloc();'
	if (MallocFunc == 0) {
	MallocType = FunctionType::get(PointerType::get(Type::SByteTy),
	std::vector<const Type*>(), true);
	MallocFunc = M.getFunction("malloc", MallocType);
	}

	// Check to see if the prototype was forgotten, giving us void (...) * free
	// This handles the common forward declaration of: 'void free();'
	if (FreeFunc == 0) {
	FreeType = FunctionType::get(Type::VoidTy, std::vector<const Type*>(),true);
	FreeFunc = M.getFunction("free", FreeType);
	}

	// One last try, check to see if we can find free as 'int (...)* free'. This
	// handles the case where NOTHING was declared.
	if (FreeFunc == 0) {
	FreeType = FunctionType::get(Type::IntTy, std::vector<const Type*>(),true);
	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;
	}

	// run - Transform calls into instructions...
	//
	bool RaiseAllocations::runOnModule(Module &M) {
	// Find the malloc/free prototypes...
	doInitialization(M);

	bool Changed = false;

	// 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_begin() != CS.arg_end() &&
	(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::UIntTy)
	Source = new CastInst(Source, Type::UIntTy, "MallocAmtCast", I);

	std::string Name(I->getName()); I->setName("");
	MallocInst *MI = new MallocInst(Type::SByteTy, Source, Name, 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->getOpcode() == Instruction::Cast) {
	Users.insert(Users.end(), CE->use_begin(), CE->use_end());
	EqPointers.push_back(CE);
	}
	}
	}
	}

	// 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)) {
	CallSite CS = CallSite::get(I);
	if (CS.getInstruction() && CS.arg_begin() != CS.arg_end() &&
	(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 CastInst(Source, PointerType::get(Type::SByteTy),
	"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->getOpcode() == Instruction::Cast) {
	Users.insert(Users.end(), CE->use_begin(), CE->use_end());
	EqPointers.push_back(CE);
	}
	}
	}
	}

	return Changed;
	}