BugDriver.cpp

//===- BugDriver.cpp - Top-Level BugPoint class implementation ------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class contains all of the shared state and information that is used by
// the BugPoint tool to track down errors in optimizations.  This class is the
// main driver class that invokes all sub-functionality.
//
//===----------------------------------------------------------------------===//

#include "BugDriver.h"
#include "ToolRunner.h"
#include "llvm/Linker.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Assembly/Parser.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include <iostream>
#include <memory>
using namespace llvm;

// Anonymous namespace to define command line options for debugging.
//
namespace {
  // Output - The user can specify a file containing the expected output of the
  // program.  If this filename is set, it is used as the reference diff source,
  // otherwise the raw input run through an interpreter is used as the reference
  // source.
  //
  cl::opt<std::string>
  OutputFile("output", cl::desc("Specify a reference program output "
                                "(for miscompilation detection)"));
}

/// setNewProgram - If we reduce or update the program somehow, call this method
/// to update bugdriver with it.  This deletes the old module and sets the
/// specified one as the current program.
void BugDriver::setNewProgram(Module *M) {
  delete Program;
  Program = M;
}


/// getPassesString - Turn a list of passes into a string which indicates the
/// command line options that must be passed to add the passes.
///
std::string llvm::getPassesString(const std::vector<const PassInfo*> &Passes) {
  std::string Result;
  for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
    if (i) Result += " ";
    Result += "-";
    Result += Passes[i]->getPassArgument();
  }
  return Result;
}

BugDriver::BugDriver(const char *toolname, bool as_child, bool find_bugs,
                     unsigned timeout, unsigned memlimit)
  : ToolName(toolname), ReferenceOutputFile(OutputFile),
    Program(0), Interpreter(0), SafeInterpreter(0), gcc(0),
    run_as_child(as_child),
    run_find_bugs(find_bugs), Timeout(timeout), MemoryLimit(memlimit) {}


/// ParseInputFile - Given a bitcode or assembly input filename, parse and
/// return it, or return null if not possible.
///
Module *llvm::ParseInputFile(const std::string &Filename) {
  std::auto_ptr<MemoryBuffer> Buffer(MemoryBuffer::getFileOrSTDIN(Filename));
  Module *Result = 0;
  if (Buffer.get())
    Result = ParseBitcodeFile(Buffer.get());
  
  ParseError Err;
  if (!Result && !(Result = ParseAssemblyFile(Filename, Err))) {
    Err.PrintError("bugpoint", errs()); 
    Result = 0;
  }
  
  return Result;
}

// This method takes the specified list of LLVM input files, attempts to load
// them, either as assembly or bitcode, then link them together. It returns
// true on failure (if, for example, an input bitcode file could not be
// parsed), and false on success.
//
bool BugDriver::addSources(const std::vector<std::string> &Filenames) {
  assert(Program == 0 && "Cannot call addSources multiple times!");
  assert(!Filenames.empty() && "Must specify at least on input filename!");

  try {
    // Load the first input file.
    Program = ParseInputFile(Filenames[0]);
    if (Program == 0) return true;
    
    if (!run_as_child)
      std::cout << "Read input file      : '" << Filenames[0] << "'\n";

    for (unsigned i = 1, e = Filenames.size(); i != e; ++i) {
      std::auto_ptr<Module> M(ParseInputFile(Filenames[i]));
      if (M.get() == 0) return true;

      if (!run_as_child)
        std::cout << "Linking in input file: '" << Filenames[i] << "'\n";
      std::string ErrorMessage;
      if (Linker::LinkModules(Program, M.get(), &ErrorMessage)) {
        std::cerr << ToolName << ": error linking in '" << Filenames[i] << "': "
                  << ErrorMessage << '\n';
        return true;
      }
    }
  } catch (const std::string &Error) {
    std::cerr << ToolName << ": error reading input '" << Error << "'\n";
    return true;
  }

  if (!run_as_child)
    std::cout << "*** All input ok\n";

  // All input files read successfully!
  return false;
}



/// run - The top level method that is invoked after all of the instance
/// variables are set up from command line arguments.
///
bool BugDriver::run() {
  // The first thing to do is determine if we're running as a child. If we are,
  // then what to do is very narrow. This form of invocation is only called
  // from the runPasses method to actually run those passes in a child process.
  if (run_as_child) {
    // Execute the passes
    return runPassesAsChild(PassesToRun);
  }
  
  if (run_find_bugs) {
    // Rearrange the passes and apply them to the program. Repeat this process
    // until the user kills the program or we find a bug.
    return runManyPasses(PassesToRun);
  }

  // If we're not running as a child, the first thing that we must do is 
  // determine what the problem is. Does the optimization series crash the 
  // compiler, or does it produce illegal code?  We make the top-level 
  // decision by trying to run all of the passes on the the input program, 
  // which should generate a bitcode file.  If it does generate a bitcode 
  // file, then we know the compiler didn't crash, so try to diagnose a 
  // miscompilation.
  if (!PassesToRun.empty()) {
    std::cout << "Running selected passes on program to test for crash: ";
    if (runPasses(PassesToRun))
      return debugOptimizerCrash();
  }

  // Set up the execution environment, selecting a method to run LLVM bitcode.
  if (initializeExecutionEnvironment()) return true;

  // Test to see if we have a code generator crash.
  std::cout << "Running the code generator to test for a crash: ";
  try {
    compileProgram(Program);
    std::cout << '\n';
  } catch (ToolExecutionError &TEE) {
    std::cout << TEE.what();
    return debugCodeGeneratorCrash();
  }


  // Run the raw input to see where we are coming from.  If a reference output
  // was specified, make sure that the raw output matches it.  If not, it's a
  // problem in the front-end or the code generator.
  //
  bool CreatedOutput = false;
  if (ReferenceOutputFile.empty()) {
    std::cout << "Generating reference output from raw program: ";
    if(!createReferenceFile(Program)){
      return debugCodeGeneratorCrash();
    }
    CreatedOutput = true;
  }

  // Make sure the reference output file gets deleted on exit from this
  // function, if appropriate.
  sys::Path ROF(ReferenceOutputFile);
  FileRemover RemoverInstance(ROF, CreatedOutput);

  // Diff the output of the raw program against the reference output.  If it
  // matches, then we assume there is a miscompilation bug and try to 
  // diagnose it.
  std::cout << "*** Checking the code generator...\n";
  try {
    if (!diffProgram()) {
      std::cout << "\n*** Debugging miscompilation!\n";
      return debugMiscompilation();
    }
  } catch (ToolExecutionError &TEE) {
    std::cerr << TEE.what();
    return debugCodeGeneratorCrash();
  }

  std::cout << "\n*** Input program does not match reference diff!\n";
  std::cout << "Debugging code generator problem!\n";
  try {
    return debugCodeGenerator();
  } catch (ToolExecutionError &TEE) {
    std::cerr << TEE.what();
    return debugCodeGeneratorCrash();
  }
}

void llvm::PrintFunctionList(const std::vector<Function*> &Funcs) {
  unsigned NumPrint = Funcs.size();
  if (NumPrint > 10) NumPrint = 10;
  for (unsigned i = 0; i != NumPrint; ++i)
    std::cout << " " << Funcs[i]->getName();
  if (NumPrint < Funcs.size())
    std::cout << "... <" << Funcs.size() << " total>";
  std::cout << std::flush;
}

void llvm::PrintGlobalVariableList(const std::vector<GlobalVariable*> &GVs) {
  unsigned NumPrint = GVs.size();
  if (NumPrint > 10) NumPrint = 10;
  for (unsigned i = 0; i != NumPrint; ++i)
    std::cout << " " << GVs[i]->getName();
  if (NumPrint < GVs.size())
    std::cout << "... <" << GVs.size() << " total>";
  std::cout << std::flush;
}