//===------------------------------------------------------------------------===
// LLVM 'AS' UTILITY 
//
//  This utility may be invoked in the following manner:
//   as --help     - Output information about command line switches
//   as [options]      - Read LLVM assembly from stdin, write bytecode to stdout
//   as [options] x.ll - Read LLVM assembly from the x.ll file, write bytecode
//                       to the x.bc file.
//
//===------------------------------------------------------------------------===

#include "llvm/Module.h"
#include "llvm/Assembly/Parser.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Bytecode/Writer.h"
#include "Support/CommandLine.h"
#include <fstream>
#include <string>
#include <memory>

cl::String InputFilename ("", "Parse <arg> file, compile to bytecode", 0, "-");
cl::String OutputFilename("o", "Override output filename", cl::NoFlags, "");
cl::Flag   Force         ("f", "Overwrite output files", cl::NoFlags, false);
cl::Flag   DumpAsm       ("d", "Print assembly as parsed", cl::Hidden, false);

int main(int argc, char **argv) {
  cl::ParseCommandLineOptions(argc, argv, " llvm .ll -> .bc assembler\n");

  ostream *Out = 0;
  try {
    // Parse the file now...
    std::auto_ptr<Module> C(ParseAssemblyFile(InputFilename));
    if (C.get() == 0) {
      cerr << "assembly didn't read correctly.\n";
      return 1;
    }
  
    if (DumpAsm)
      cerr << "Here's the assembly:\n" << C.get();

    if (OutputFilename != "") {   // Specified an output filename?
      if (!Force && !std::ifstream(OutputFilename.c_str())) {
        // If force is not specified, make sure not to overwrite a file!
        cerr << "Error opening '" << OutputFilename << "': File exists!\n"
             << "Use -f command line argument to force output\n";
        return 1;
      }
      Out = new std::ofstream(OutputFilename.c_str());
    } else {
      if (InputFilename == "-") {
	OutputFilename = "-";
	Out = &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 .bc to it
	}
	OutputFilename += ".bc";

        if (!Force && !std::ifstream(OutputFilename.c_str())) {
          // If force is not specified, make sure not to overwrite a file!
          cerr << "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()) {
      cerr << "Error opening " << OutputFilename << "!\n";
      return 1;
    }
   
    WriteBytecodeToFile(C.get(), *Out);
  } catch (const ParseException &E) {
    cerr << E.getMessage() << endl;
    return 1;
  }

  if (Out != &cout) delete Out;
  return 0;
}