tools/opt/opt.cpp

//===- opt.cpp - The LLVM Modular Optimizer -------------------------------===//
// 
//                     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.
// 
//===----------------------------------------------------------------------===//
//
// Optimizations may be specified an arbitrary number of times on the command
// line, they are run in the order specified.
//
//===----------------------------------------------------------------------===//

#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/WriteBytecodePass.h"
#include "llvm/Assembly/PrintModulePass.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/PassNameParser.h"
#include "llvm/System/Signals.h"
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/SystemUtils.h"
#include <fstream>
#include <memory>
#include <algorithm>

using namespace llvm;

// The OptimizationList is automatically populated with registered Passes by the
// PassNameParser.
//
static cl::list<const PassInfo*, bool,
                FilteredPassNameParser<PassInfo::Optimization> >
OptimizationList(cl::desc("Optimizations available:"));


// Other command line options...
//
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input bytecode>"), cl::init("-"));

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

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

static cl::opt<bool>
PrintEachXForm("p", cl::desc("Print module after each transformation"));

static cl::opt<bool>
NoOutput("disable-output",
         cl::desc("Do not write result bytecode file"), cl::Hidden);

static cl::opt<bool>
NoVerify("disable-verify", cl::desc("Do not verify result module"), cl::Hidden);

static cl::opt<bool>
Quiet("q", cl::desc("Obsolete option"), cl::Hidden);

static cl::alias
QuietA("quiet", cl::desc("Alias for -q"), cl::aliasopt(Quiet));


//===----------------------------------------------------------------------===//
// main for opt
//
int main(int argc, char **argv) {
  try {
    cl::ParseCommandLineOptions(argc, argv,
                                " llvm .bc -> .bc modular optimizer\n");
    sys::PrintStackTraceOnErrorSignal();

    // Allocate a full target machine description only if necessary...
    // FIXME: The choice of target should be controllable on the command line.
    std::auto_ptr<TargetMachine> target;

    TargetMachine* TM = NULL;
    std::string ErrorMessage;

    // Load the input module...
    std::auto_ptr<Module> M(ParseBytecodeFile(InputFilename, &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;
    }

    // Figure out what stream we are supposed to write to...
    std::ostream *Out = &std::cout;  // Default to printing to stdout...
    if (OutputFilename != "-") {
      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());

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

      // Make sure that the Output file gets unlinked from the disk if we get a
      // SIGINT
      sys::RemoveFileOnSignal(sys::Path(OutputFilename));
    }

    // If the output is set to be emitted to standard out, and standard out is a
    // console, print out a warning message and refuse to do it.  We don't impress
    // anyone by spewing tons of binary goo to a terminal.
    if (Out == &std::cout && isStandardOutAConsole() && !Force && !NoOutput 
        && !Quiet) {
      std::cerr << "WARNING: It looks like you're attempting to print out a "
                << "bytecode file.  I'm\ngoing to pretend you didn't ask me to do"
                << " this (for your own good).  If you\nREALLY want to taste LLVM"
                << " bytecode first-hand, you can force output with the\n`-f'"
                << " option.\n\n";
      NoOutput = true;
    }

    // Create a PassManager to hold and optimize the collection of passes we are
    // about to build...
    //
    PassManager Passes;

    // Add an appropriate TargetData instance for this module...
    Passes.add(new TargetData("opt", M.get()));

    // Create a new optimization pass for each one specified on the command line
    for (unsigned i = 0; i < OptimizationList.size(); ++i) {
      const PassInfo *Opt = OptimizationList[i];
      
      if (Opt->getNormalCtor())
        Passes.add(Opt->getNormalCtor()());
      else if (Opt->getTargetCtor()) {
#if 0
        if (target.get() == NULL)
          target.reset(allocateSparcTargetMachine()); // FIXME: target option
#endif
        assert(target.get() && "Could not allocate target machine!");
        Passes.add(Opt->getTargetCtor()(*target.get()));
      } else
        std::cerr << argv[0] << ": cannot create pass: " << Opt->getPassName()
                  << "\n";

      if (PrintEachXForm)
        Passes.add(new PrintModulePass(&std::cerr));
    }

    // Check that the module is well formed on completion of optimization
    if (!NoVerify)
      Passes.add(createVerifierPass());

    // Write bytecode out to disk or cout as the last step...
    if (!NoOutput)
      Passes.add(new WriteBytecodePass(Out, Out != &std::cout));

    // Now that we have all of the passes ready, run them.
    Passes.run(*M.get());

    return 0;
  } catch (const std::string& msg) {
    std::cerr << argv[0] << ": " << msg << "\n";
  } catch (...) {
    std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
  }
  return 1;
}