llvm-project/llvm/tools/bugpoint/ExtractFunction.cpp

281 lines
11 KiB
C++

//===- 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 several methods that are used to extract functions,
// loops, or portions of a module from the rest of the 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/Transforms/Utils/FunctionUtils.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileUtilities.h"
#include <set>
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));
/// FIXME: If this used runPasses() like the methods below, we could get rid
/// of the -disable-* options!
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()));
Module *New = runPassesOn(M, CleanupPasses);
if (New == 0) {
std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
return M;
}
delete M;
return New;
}
/// 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()));
Module *NewM = runPassesOn(M, LoopExtractPasses);
if (NewM == 0) {
Module *Old = swapProgramIn(M);
std::cout << "*** Loop extraction failed: ";
EmitProgressBytecode("loopextraction", true);
std::cout << "*** Sorry. :( Please report a bug!\n";
swapProgramIn(Old);
return 0;
}
// Check to see if we created any new functions. If not, no loops were
// extracted and we should return null. Limit the number of loops we extract
// to avoid taking forever.
static unsigned NumExtracted = 32;
if (M->size() == NewM->size() || --NumExtracted == 0) {
delete NewM;
return 0;
} else {
assert(M->size() < NewM->size() && "Loop extract removed functions?");
Module::iterator MI = NewM->begin();
for (unsigned i = 0, e = M->size(); i != e; ++i)
++MI;
}
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::global_iterator I = M->global_begin(), E = M->global_end(); 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::global_iterator I = New->global_begin(), E = New->global_end(); I != E; ++I)
I->setInitializer(0); // Delete the initializer to make it external
// Remove the Test functions from the Safe module
std::set<std::pair<std::string, const PointerType*> > TestFunctions;
for (unsigned i = 0, e = F.size(); i != e; ++i) {
TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
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)
if (!TestFunctions.count(std::make_pair(I->getName(), I->getType())))
DeleteFunctionBody(I);
return New;
}
//===----------------------------------------------------------------------===//
// Basic Block Extraction Code
//===----------------------------------------------------------------------===//
namespace {
std::vector<BasicBlock*> BlocksToNotExtract;
/// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
/// from the module into their own functions except for those specified by the
/// BlocksToNotExtract list.
class BlockExtractorPass : public ModulePass {
bool runOnModule(Module &M);
};
RegisterOpt<BlockExtractorPass>
XX("extract-bbs", "Extract Basic Blocks From Module (for bugpoint use)");
}
bool BlockExtractorPass::runOnModule(Module &M) {
std::set<BasicBlock*> TranslatedBlocksToNotExtract;
for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
BasicBlock *BB = BlocksToNotExtract[i];
Function *F = BB->getParent();
// Map the corresponding function in this module.
Function *MF = M.getFunction(F->getName(), F->getFunctionType());
// Figure out which index the basic block is in its function.
Function::iterator BBI = MF->begin();
std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
TranslatedBlocksToNotExtract.insert(BBI);
}
// Now that we know which blocks to not extract, figure out which ones we WANT
// to extract.
std::vector<BasicBlock*> BlocksToExtract;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
if (!TranslatedBlocksToNotExtract.count(BB))
BlocksToExtract.push_back(BB);
for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
ExtractBasicBlock(BlocksToExtract[i]);
return !BlocksToExtract.empty();
}
/// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
/// into their own functions. The only detail is that M is actually a module
/// cloned from the one the BBs are in, so some mapping needs to be performed.
/// If this operation fails for some reason (ie the implementation is buggy),
/// this function should return null, otherwise it returns a new Module.
Module *BugDriver::ExtractMappedBlocksFromModule(const
std::vector<BasicBlock*> &BBs,
Module *M) {
// Set the global list so that pass will be able to access it.
BlocksToNotExtract = BBs;
std::vector<const PassInfo*> PI;
PI.push_back(getPI(new BlockExtractorPass()));
Module *Ret = runPassesOn(M, PI);
BlocksToNotExtract.clear();
if (Ret == 0) {
std::cout << "*** Basic Block extraction failed, please report a bug!\n";
M = swapProgramIn(M);
EmitProgressBytecode("basicblockextractfail", true);
M = swapProgramIn(M);
}
return Ret;
}