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//===- ExtractFunction.cpp - Extract a function from Program --------------===//
//
// 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/Type.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "Support/CommandLine.h"
bool DisableSimplifyCFG = false;
namespace {
cl::opt<bool>
NoADCE("disable-adce",
cl::desc("Do not use the -adce pass to reduce testcases"));
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"));
cl::opt<bool>
NoFinalCleanup("disable-final-cleanup",
cl::desc("Disable the final cleanup phase of narrowing"));
}
/// 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(Instruction *I,
unsigned Simplification) const {
Module *Result = CloneModule(Program);
BasicBlock *PBB = I->getParent();
Function *PF = PBB->getParent();
Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
std::advance(RFI, std::distance(Program->begin(), Module::iterator(PF)));
Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
std::advance(RBI, std::distance(PF->begin(), Function::iterator(PBB)));
BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
std::advance(RI, std::distance(PBB->begin(), BasicBlock::iterator(I)));
I = RI; // Got the corresponding instruction!
// If this instruction produces a value, replace any users with null values
if (I->getType() != Type::VoidTy)
I->replaceAllUsesWith(Constant::getNullValue(I->getType()));
// Remove the instruction from the program.
I->getParent()->getInstList().erase(I);
// Spiff up the output a little bit.
PassManager Passes;
if (Simplification > 2 && !NoADCE)
Passes.add(createAggressiveDCEPass()); // Remove dead code...
//Passes.add(createInstructionCombiningPass());
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;
}
/// 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 *InM) const {
Module *M = InM ? InM : CloneModule(Program);
// Allow disabling these passes if they crash bugpoint.
//
// FIXME: This should eventually run these passes in a pass list to prevent
// them from being able to crash bugpoint at all!
//
if (NoFinalCleanup) return M;
// 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);
PassManager CleanupPasses;
CleanupPasses.add(createFunctionResolvingPass());
CleanupPasses.add(createGlobalDCEPass());
CleanupPasses.add(createDeadTypeEliminationPass());
CleanupPasses.add(createDeadArgEliminationPass(InM == 0));
CleanupPasses.add(createVerifierPass());
CleanupPasses.run(*M);
return M;
}
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