tools/llvm2cpp/llvm2cpp.cpp

//===--- llvm2cpp.cpp - LLVM IR to C++ Translator -------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This program converts an input LLVM assembly file (.ll) into a C++ source
// file that makes calls to the LLVM C++ API to produce the same module. The
// generated program verifies what it built and then runs the PrintAssemblyPass
// to reproduce the input originally given to llvm2cpp.
//
// Use the --help option for help with command line options.
//
//===------------------------------------------------------------------------===

#include "llvm/Module.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/System/Signals.h"
#include "CppWriter.h"
#include <fstream>
#include <iostream>
#include <memory>

using namespace llvm;

static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input LLVM bytecode file>"), 
  cl::init("-"));

static cl::opt<std::string>
OutputFilename("o", cl::desc("Override output filename"),
               cl::value_desc("filename"));

static cl::opt<bool>
Force("f", cl::desc("Overwrite output files"));

int main(int argc, char **argv) {
  llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
  cl::ParseCommandLineOptions(argc, argv, " llvm .ll -> .cpp assembler\n");
  sys::PrintStackTraceOnErrorSignal();

  int exitCode = 0;
  std::ostream *Out = 0;
  std::string ErrorMessage;
  std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename, 
                                            Compressor::decompressToNewBuffer, 
                                            &ErrorMessage));
  if (M.get() == 0) {
    std::cerr << argv[0] << ": ";
    if (ErrorMessage.size())
      std::cerr << ErrorMessage << "\n";
    else
      std::cerr << "bytecode didn't read correctly.\n";
    return 1;
  }

  if (OutputFilename != "") {   // Specified an output filename?
    if (OutputFilename != "-") {  // Not stdout?
      if (!Force && std::ifstream(OutputFilename.c_str())) {
        // If force is not specified, make sure not to overwrite a file!
        std::cerr << argv[0] << ": error opening '" << OutputFilename
                  << "': file exists!\n"
                  << "Use -f command line argument to force output\n";
        return 1;
      }
      Out = new std::ofstream(OutputFilename.c_str(), std::ios::out |
                              std::ios::trunc | std::ios::binary);
    } else {                      // Specified stdout
      Out = &std::cout;
    }
  } else {
    if (InputFilename == "-") {
      OutputFilename = "-";
      Out = &std::cout;
    } else {
      std::string IFN = InputFilename;
      int Len = IFN.length();
      if (IFN[Len-3] == '.' && IFN[Len-2] == 'l' && IFN[Len-1] == 'l') {
        // Source ends in .ll
        OutputFilename = std::string(IFN.begin(), IFN.end()-3);
      } else {
        OutputFilename = IFN;   // Append a .cpp to it
      }
      OutputFilename += ".cpp";

      if (!Force && std::ifstream(OutputFilename.c_str())) {
        // If force is not specified, make sure not to overwrite a file!
        std::cerr << argv[0] << ": error opening '" << OutputFilename
                  << "': file exists!\n"
                  << "Use -f command line argument to force output\n";
        return 1;
      }

      Out = new std::ofstream(OutputFilename.c_str(), std::ios::out |
                              std::ios::trunc | std::ios::binary);
      // Make sure that the Out file gets unlinked from the disk if we get a
      // SIGINT
      sys::RemoveFileOnSignal(sys::Path(OutputFilename));
    }
  }

  if (!Out->good()) {
    std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
    return 1;
  }

  WriteModuleToCppFile(M.get(), *Out);

  if (Out != &std::cout) delete Out;
  return exitCode;
}