llvm.org GIT mirror llvm / 4e1be6d tools / bugpoint / ExtractFunction.cpp
4e1be6d

Tree @4e1be6d (Download .tar.gz)

ExtractFunction.cpp @4e1be6d

afade92
3da94ae
7c0e022
 
 
 
3da94ae
7c0e022
afade92
efdc0b5
 
afade92
 
 
 
5a7a9e5
 
afade92
 
d1a85a7
e49603d
afade92
6520785
afade92
5e783ab
5da69c7
551ccae
 
 
fb4b96e
e31a9cc
c6b519d
d0fde30
 
c6b519d
d0fde30
 
6db70ef
 
 
 
47ae4a1
 
6db70ef
 
afade92
6520785
 
 
 
 
0cc8807
6520785
 
 
0cc8807
 
6520785
 
0cc8807
 
6520785
 
0cc8807
6520785
 
0cc8807
 
6520785
 
0cc8807
 
6520785
 
0cc8807
6520785
5a7a9e5
 
 
44be257
6520785
5da69c7
831b121
5da69c7
efdc0b5
 
6db70ef
6520785
47ae4a1
6520785
10f22cb
 
6520785
 
 
ba386d9
fcb6ec0
 
 
 
 
 
ba386d9
 
9b5b190
ba386d9
fcb6ec0
28b8ed9
 
 
3da94ae
fcb6ec0
 
 
 
c6b519d
 
 
 
fcb6ec0
a75766a
 
7546c38
9b5b190
fcb6ec0
a75766a
 
ba386d9
be21ca5
 
7546c38
 
 
 
 
 
 
a75766a
 
a1cf1c8
 
8ff70c2
a1cf1c8
 
7546c38
 
a75766a
 
a269ec7
 
 
90c18c5
a75766a
 
90c18c5
 
 
 
 
a75766a
3da94ae
a75766a
7546c38
 
 
be21ca5
 
 
 
 
 
5cbf985
be21ca5
 
5a7a9e5
 
 
 
 
 
 
71d2ec9
5a7a9e5
 
 
 
 
 
 
 
 
 
 
 
 
 
5cbf985
5a7a9e5
 
 
 
 
 
 
 
 
 
 
 
 
b83eb64
 
5a7a9e5
 
 
3da59db
5a7a9e5
 
5cbf985
5a7a9e5
 
 
ef9b9a7
5a7a9e5
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
e47863e
be21ca5
 
 
 
 
 
 
 
 
5a7a9e5
 
be21ca5
 
fef0242
be21ca5
fef0242
 
 
 
be21ca5
fef0242
fb4b96e
be21ca5
e47863e
ef9b9a7
fef0242
ef9b9a7
 
fef0242
e47863e
 
5a7a9e5
fef0242
 
 
 
 
e47863e
5a7a9e5
 
 
 
 
be21ca5
 
5e783ab
 
 
 
 
 
 
 
 
 
 
 
 
 
4e1be6d
 
5e783ab
891150f
5e783ab
891150f
8ff70c2
b923b2e
891150f
5e783ab
 
//===- 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/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Pass.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>
#include <iostream>
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);

  
  //writeProgramToFile("current.bc", Result);
    
  // Spiff up the output a little bit.
  PassManager Passes;
  // Make sure that the appropriate target data is always used...
  Passes.add(new TargetData(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(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: ";
    EmitProgressBitcode("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->isDeclaration() && "This didn't make the function external!");
}

/// GetTorInit - Given a list of entries for static ctors/dtors, return them
/// as a constant array.
static Constant *GetTorInit(std::vector<std::pair<Function*, int> > &TorList) {
  assert(!TorList.empty() && "Don't create empty tor list!");
  std::vector<Constant*> ArrayElts;
  for (unsigned i = 0, e = TorList.size(); i != e; ++i) {
    std::vector<Constant*> Elts;
    Elts.push_back(ConstantInt::get(Type::Int32Ty, TorList[i].second));
    Elts.push_back(TorList[i].first);
    ArrayElts.push_back(ConstantStruct::get(Elts));
  }
  return ConstantArray::get(ArrayType::get(ArrayElts[0]->getType(), 
                                           ArrayElts.size()),
                            ArrayElts);
}

/// SplitStaticCtorDtor - A module was recently split into two parts, M1/M2, and
/// M1 has all of the global variables.  If M2 contains any functions that are
/// static ctors/dtors, we need to add an llvm.global_[cd]tors global to M2, and
/// prune appropriate entries out of M1s list.
static void SplitStaticCtorDtor(const char *GlobalName, Module *M1, Module *M2){
  GlobalVariable *GV = M1->getNamedGlobal(GlobalName);
  if (!GV || GV->isDeclaration() || GV->hasInternalLinkage() ||
      !GV->use_empty()) return;
  
  std::vector<std::pair<Function*, int> > M1Tors, M2Tors;
  ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  if (!InitList) return;
  
  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
    if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
      if (CS->getNumOperands() != 2) return;  // Not array of 2-element structs.
      
      if (CS->getOperand(1)->isNullValue())
        break;  // Found a null terminator, stop here.
      
      ConstantInt *CI = dyn_cast<ConstantInt>(CS->getOperand(0));
      int Priority = CI ? CI->getSExtValue() : 0;
      
      Constant *FP = CS->getOperand(1);
      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
        if (CE->isCast())
          FP = CE->getOperand(0);
      if (Function *F = dyn_cast<Function>(FP)) {
        if (!F->isDeclaration())
          M1Tors.push_back(std::make_pair(F, Priority));
        else {
          // Map to M2's version of the function.
          F = M2->getFunction(F->getName());
          M2Tors.push_back(std::make_pair(F, Priority));
        }
      }
    }
  }
  
  GV->eraseFromParent();
  if (!M1Tors.empty()) {
    Constant *M1Init = GetTorInit(M1Tors);
    new GlobalVariable(M1Init->getType(), false, GlobalValue::AppendingLinkage,
                       M1Init, GlobalName, M1);
  }

  GV = M2->getNamedGlobal(GlobalName);
  assert(GV && "Not a clone of M1?");
  assert(GV->use_empty() && "llvm.ctors shouldn't have uses!");

  GV->eraseFromParent();
  if (!M2Tors.empty()) {
    Constant *M2Init = GetTorInit(M2Tors);
    new GlobalVariable(M2Init->getType(), false, GlobalValue::AppendingLinkage,
                       M2Init, GlobalName, M2);
  }
}


/// 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.
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());
    assert(TNOF && "Function doesn't exist in module!");
    assert(TNOF->getFunctionType() == F[i]->getFunctionType() && "wrong type?");
    DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
    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);
  

  // Make sure that there is a global ctor/dtor array in both halves of the
  // module if they both have static ctor/dtor functions.
  SplitStaticCtorDtor("llvm.global_ctors", M, New);
  SplitStaticCtorDtor("llvm.global_dtors", M, New);
  
  return New;
}

//===----------------------------------------------------------------------===//
// Basic Block Extraction Code
//===----------------------------------------------------------------------===//

/// 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) {
  std::vector<const PassInfo*> PI;
  // FIXME: BBs is actually ignored. See http://llvm.org/PR1775
  PI.push_back(getPI(createBlockExtractorPass(BBs)));
  Module *Ret = runPassesOn(M, PI);
  if (Ret == 0) {
    std::cout << "*** Basic Block extraction failed, please report a bug!\n";
    M = swapProgramIn(M);
    EmitProgressBitcode("basicblockextractfail", true);
    swapProgramIn(M);
  }
  return Ret;
}