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//===- ExtractFunction.cpp - Extract a function from Program --------------===//
//
// 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 implements a method that extracts a function from program, cleans
// it up, and returns it as a new module.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "llvm/Constant.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Target/TargetData.h"
#include "Support/CommandLine.h"
#include "Support/Debug.h"
#include "Support/FileUtilities.h"
using namespace llvm;
namespace llvm {
bool DisableSimplifyCFG = false;
} // End llvm namespace
namespace {
cl::opt<bool>
NoDCE ("disable-dce",
cl::desc("Do not use the -dce pass to reduce testcases"));
cl::opt<bool, true>
NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
}
/// deleteInstructionFromProgram - This method clones the current Program and
/// deletes the specified instruction from the cloned module. It then runs a
/// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
/// depends on the value. The modified module is then returned.
///
Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
unsigned Simplification) const {
Module *Result = CloneModule(Program);
const BasicBlock *PBB = I->getParent();
const Function *PF = PBB->getParent();
Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
std::advance(RFI, std::distance(PF->getParent()->begin(),
Module::const_iterator(PF)));
Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
Instruction *TheInst = RI; // Got the corresponding instruction!
// If this instruction produces a value, replace any users with null values
if (TheInst->getType() != Type::VoidTy)
TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
// Remove the instruction from the program.
TheInst->getParent()->getInstList().erase(TheInst);
// Spiff up the output a little bit.
PassManager Passes;
// Make sure that the appropriate target data is always used...
Passes.add(new TargetData("bugpoint", Result));
if (Simplification > 1 && !NoDCE)
Passes.add(createDeadCodeEliminationPass());
if (Simplification && !DisableSimplifyCFG)
Passes.add(createCFGSimplificationPass()); // Delete dead control flow
Passes.add(createVerifierPass());
Passes.run(*Result);
return Result;
}
static const PassInfo *getPI(Pass *P) {
const PassInfo *PI = P->getPassInfo();
delete P;
return PI;
}
/// performFinalCleanups - This method clones the current Program and performs
/// a series of cleanups intended to get rid of extra cruft on the module
/// before handing it to the user...
///
Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
// Make all functions external, so GlobalDCE doesn't delete them...
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
I->setLinkage(GlobalValue::ExternalLinkage);
std::vector<const PassInfo*> CleanupPasses;
CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
CleanupPasses.push_back(getPI(createGlobalDCEPass()));
CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
if (MayModifySemantics)
CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
else
CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
std::swap(Program, M);
std::string Filename;
bool Failed = runPasses(CleanupPasses, Filename);
std::swap(Program, M);
if (Failed) {
std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
} else {
delete M;
M = ParseInputFile(Filename);
if (M == 0) {
std::cerr << getToolName() << ": Error reading bytecode file '"
<< Filename << "'!\n";
exit(1);
}
removeFile(Filename);
}
return M;
}
/// ExtractLoop - Given a module, extract up to one loop from it into a new
/// function. This returns null if there are no extractable loops in the
/// program or if the loop extractor crashes.
Module *BugDriver::ExtractLoop(Module *M) {
std::vector<const PassInfo*> LoopExtractPasses;
LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
std::swap(Program, M);
std::string Filename;
bool Failed = runPasses(LoopExtractPasses, Filename);
std::swap(Program, M);
if (Failed) {
std::cerr << "Loop extraction failed. Sorry. :( Please report a bug!\n";
return 0;
} else {
Module *NewM = ParseInputFile(Filename);
if (NewM == 0) {
std::cerr << getToolName() << ": Error reading bytecode file '"
<< Filename << "'!\n";
exit(1);
}
removeFile(Filename);
// Check to see if we created any new functions. If not, no loops were
// extracted and we should return null.
if (M->size() != NewM->size()) {
delete NewM;
return 0;
}
return NewM;
}
}
// DeleteFunctionBody - "Remove" the function by deleting all of its basic
// blocks, making it external.
//
void llvm::DeleteFunctionBody(Function *F) {
// delete the body of the function...
F->deleteBody();
assert(F->isExternal() && "This didn't make the function external!");
}
/// SplitFunctionsOutOfModule - Given a module and a list of functions in the
/// module, split the functions OUT of the specified module, and place them in
/// the new module.
///
/// FIXME: this could be made DRAMATICALLY more efficient for large programs if
/// we just MOVED functions from one module to the other, instead of cloning the
/// whole module, then proceeding to delete an entire module's worth of stuff.
///
Module *llvm::SplitFunctionsOutOfModule(Module *M,
const std::vector<Function*> &F) {
// Make sure functions & globals are all external so that linkage
// between the two modules will work.
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
I->setLinkage(GlobalValue::ExternalLinkage);
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
I->setLinkage(GlobalValue::ExternalLinkage);
Module *New = CloneModule(M);
// Make sure global initializers exist only in the safe module (CBE->.so)
for (Module::giterator I = New->gbegin(), E = New->gend(); I != E; ++I)
I->setInitializer(0); // Delete the initializer to make it external
// Remove the Test functions from the Safe module
for (unsigned i = 0, e = F.size(); i != e; ++i) {
Function *TNOF = M->getFunction(F[i]->getName(), F[i]->getFunctionType());
DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
assert(TNOF && "Function doesn't exist in module!");
DeleteFunctionBody(TNOF); // Function is now external in this module!
}
// Remove the Safe functions from the Test module
for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I) {
bool funcFound = false;
for (std::vector<Function*>::const_iterator FI = F.begin(), Fe = F.end();
FI != Fe; ++FI)
if (I->getName() == (*FI)->getName()) funcFound = true;
if (!funcFound)
DeleteFunctionBody(I);
}
return New;
}
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