path: root/tools/bugpoint/CrashDebugger.cpp

//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
//
//                     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 bugpoint internals that narrow down compilation crashes
//
//===----------------------------------------------------------------------===//

#include "BugDriver.h"
#include "ListReducer.h"
#include "llvm/Constant.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/SymbolTable.h"
#include "llvm/Type.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bytecode/Writer.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/ToolRunner.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Support/FileUtilities.h"
#include <fstream>
#include <set>
using namespace llvm;

namespace llvm {
  class ReducePassList : public ListReducer<const PassInfo*> {
    BugDriver &BD;
  public:
    ReducePassList(BugDriver &bd) : BD(bd) {}

    // doTest - Return true iff running the "removed" passes succeeds, and
    // running the "Kept" passes fail when run on the output of the "removed"
    // passes.  If we return true, we update the current module of bugpoint.
    //
    virtual TestResult doTest(std::vector<const PassInfo*> &Removed,
                              std::vector<const PassInfo*> &Kept);
  };
}

ReducePassList::TestResult
ReducePassList::doTest(std::vector<const PassInfo*> &Prefix,
                       std::vector<const PassInfo*> &Suffix) {
  sys::Path PrefixOutput;
  Module *OrigProgram = 0;
  if (!Prefix.empty()) {
    std::cout << "Checking to see if these passes crash: "
              << getPassesString(Prefix) << ": ";
    std::string PfxOutput;
    if (BD.runPasses(Prefix, PfxOutput))
      return KeepPrefix;

    PrefixOutput.set(PfxOutput);
    OrigProgram = BD.Program;

    BD.Program = ParseInputFile(PrefixOutput.toString());
    if (BD.Program == 0) {
      std::cerr << BD.getToolName() << ": Error reading bytecode file '"
                << PrefixOutput << "'!\n";
      exit(1);
    }
    PrefixOutput.destroy();
  }

  std::cout << "Checking to see if these passes crash: "
            << getPassesString(Suffix) << ": ";

  if (BD.runPasses(Suffix)) {
    delete OrigProgram;            // The suffix crashes alone...
    return KeepSuffix;
  }

  // Nothing failed, restore state...
  if (OrigProgram) {
    delete BD.Program;
    BD.Program = OrigProgram;
  }
  return NoFailure;
}

namespace llvm {
  class ReduceCrashingFunctions : public ListReducer<Function*> {
    BugDriver &BD;
    bool (*TestFn)(BugDriver &, Module *);
  public:
    ReduceCrashingFunctions(BugDriver &bd,
                            bool (*testFn)(BugDriver &, Module *))
      : BD(bd), TestFn(testFn) {}

    virtual TestResult doTest(std::vector<Function*> &Prefix,
                              std::vector<Function*> &Kept) {
      if (!Kept.empty() && TestFuncs(Kept))
        return KeepSuffix;
      if (!Prefix.empty() && TestFuncs(Prefix))
        return KeepPrefix;
      return NoFailure;
    }

    bool TestFuncs(std::vector<Function*> &Prefix);
  };
}

bool ReduceCrashingFunctions::TestFuncs(std::vector<Function*> &Funcs) {
  // Clone the program to try hacking it apart...
  Module *M = CloneModule(BD.getProgram());

  // Convert list to set for fast lookup...
  std::set<Function*> Functions;
  for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
    Function *CMF = M->getFunction(Funcs[i]->getName(),
                                   Funcs[i]->getFunctionType());
    assert(CMF && "Function not in module?!");
    Functions.insert(CMF);
  }

  std::cout << "Checking for crash with only these functions: ";
  PrintFunctionList(Funcs);
  std::cout << ": ";

  // Loop over and delete any functions which we aren't supposed to be playing
  // with...
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    if (!I->isExternal() && !Functions.count(I))
      DeleteFunctionBody(I);

  // Try running the hacked up program...
  if (TestFn(BD, M)) {
    BD.setNewProgram(M);        // It crashed, keep the trimmed version...

    // Make sure to use function pointers that point into the now-current
    // module.
    Funcs.assign(Functions.begin(), Functions.end());
    return true;
  }
  delete M;
  return false;
}


namespace {
  /// ReduceCrashingBlocks reducer - This works by setting the terminators of
  /// all terminators except the specified basic blocks to a 'ret' instruction,
  /// then running the simplify-cfg pass.  This has the effect of chopping up
  /// the CFG really fast which can reduce large functions quickly.
  ///
  class ReduceCrashingBlocks : public ListReducer<const BasicBlock*> {
    BugDriver &BD;
    bool (*TestFn)(BugDriver &, Module *);
  public:
    ReduceCrashingBlocks(BugDriver &bd, bool (*testFn)(BugDriver &, Module *))
      : BD(bd), TestFn(testFn) {}

    virtual TestResult doTest(std::vector<const BasicBlock*> &Prefix,
                              std::vector<const BasicBlock*> &Kept) {
      if (!Kept.empty() && TestBlocks(Kept))
        return KeepSuffix;
      if (!Prefix.empty() && TestBlocks(Prefix))
        return KeepPrefix;
      return NoFailure;
    }

    bool TestBlocks(std::vector<const BasicBlock*> &Prefix);
  };
}

bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock*> &BBs) {
  // Clone the program to try hacking it apart...
  Module *M = CloneModule(BD.getProgram());

  // Convert list to set for fast lookup...
  std::set<BasicBlock*> Blocks;
  for (unsigned i = 0, e = BBs.size(); i != e; ++i) {
    // Convert the basic block from the original module to the new module...
    const Function *F = BBs[i]->getParent();
    Function *CMF = M->getFunction(F->getName(), F->getFunctionType());
    assert(CMF && "Function not in module?!");

    // Get the mapped basic block...
    Function::iterator CBI = CMF->begin();
    std::advance(CBI, std::distance(F->begin(),
                                    Function::const_iterator(BBs[i])));
    Blocks.insert(CBI);
  }

  std::cout << "Checking for crash with only these blocks:";
  unsigned NumPrint = Blocks.size();
  if (NumPrint > 10) NumPrint = 10;
  for (unsigned i = 0, e = NumPrint; i != e; ++i)
    std::cout << " " << BBs[i]->getName();
  if (NumPrint < Blocks.size())
    std::cout << "... <" << Blocks.size() << " total>";
  std::cout << ": ";

  // Loop over and delete any hack up any blocks that are not listed...
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    for