//===------------------------------------------------------------------------===
// LLVM 'DIS' UTILITY 
//
// This utility may be invoked in the following manner:
//  dis [options]      - Read LLVM bytecode from stdin, write assembly to stdout
//  dis [options] x.bc - Read LLVM bytecode from the x.bc file, write assembly
//                       to the x.ll file.
//  Options:
//      --help   - Output information about command line switches
//       -dfo    - Print basic blocks in depth first order
//       -rdfo   - Print basic blocks in reverse depth first order
//       -po     - Print basic blocks in post order
//       -rpo    - Print basic blocks in reverse post order
//
// TODO: add -vcg which prints VCG compatible output.
//
//===------------------------------------------------------------------------===

#include <iostream.h>
#include <fstream.h>
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Tools/CommandLine.h"
#include "llvm/Method.h"
#include "llvm/CFG.h"

// OutputMode - The different orderings to print basic blocks in...
enum OutputMode {
  Default = 0,           // Method Order (list order)
  dfo,                   // Depth First ordering
  rdfo,                  // Reverse Depth First ordering
  po,                    // Post Order
  rpo,                   // Reverse Post Order
};

cl::String InputFilename ("", "Load <arg> file, print as assembly", 0, "-");
cl::String OutputFilename("o", "Override output filename", 0, "");
cl::Flag   Force         ("f", "Overwrite output files", 0, false);
cl::EnumFlags<enum OutputMode> WriteMode(cl::NoFlags,
  clEnumVal(Default, "Write bb's in bytecode order"),
  clEnumVal(dfo    , "Write bb's in depth first order"),
  clEnumVal(rdfo   , "Write bb's in reverse DFO"),
  clEnumVal(po     , "Write bb's in postorder"),
  clEnumVal(rpo    , "Write bb's in reverse postorder"), 0);

int main(int argc, char **argv) {
  cl::ParseCommandLineOptions(argc, argv, " llvm .bc -> .ll disassembler\n");
  ostream *Out = &cout;  // Default to printing to stdout...

  Module *C = ParseBytecodeFile(InputFilename.getValue());
  if (C == 0) {
    cerr << "bytecode didn't read correctly.\n";
    return 1;
  }
  
  if (OutputFilename.getValue() != "") {   // Specified an output filename?
    Out = new ofstream(OutputFilename.getValue().c_str(), 
		       (Force.getValue() ? 0 : ios::noreplace)|ios::out);
  } else {
    if (InputFilename.getValue() == "-") {
      OutputFilename.setValue("-");
      Out = &cout;
    } else {
      string IFN = InputFilename.getValue();
      int Len = IFN.length();
      if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
	// Source ends in .bc
	OutputFilename.setValue(string(IFN.begin(), IFN.end()-3));
      } else {
	OutputFilename.setValue(IFN);   // Append a .ll to it
      }
      OutputFilename.setValue(OutputFilename.getValue() + ".ll");
      Out = new ofstream(OutputFilename.getValue().c_str(), 
			 (Force.getValue() ? 0 : ios::noreplace)|ios::out);
    }
  }

  if (!Out->good()) {
    cerr << "Error opening " << OutputFilename.getValue() 
	 << ": sending to stdout instead!\n";
    Out = &cout;
  }

  // All that dis does is write the assembly out to a file... which is exactly
  // what the writer library is supposed to do...
  //
  if (WriteMode.getValue() == Default) {
    (*Out) << C;           // Print out in list order
  } else {
    // TODO: This does not print anything other than the basic blocks in the
    // methods... more should definately be printed.  It should be valid output
    // consumable by the assembler.
    //
    for (Module::iterator I = C->begin(), End = C->end(); I != End; ++I) {
      Method *M = *I;
      (*Out) << "-------------- Method: " << M->getName() << " -------------\n";

      switch (WriteMode.getValue()) {
      case dfo:                   // Depth First ordering
	copy(cfg::df_begin(M), cfg::df_end(M),
	     ostream_iterator<BasicBlock*>(*Out, "\n"));
	break;
      case rdfo:            // Reverse Depth First ordering
	copy(cfg::df_begin(M, true), cfg::df_end(M),
	     ostream_iterator<BasicBlock*>(*Out, "\n"));
	break;
      case po:                    // Post Order
	copy(cfg::po_begin(M), cfg::po_end(M),
	     ostream_iterator<BasicBlock*>(*Out, "\n"));
	break;
      case rpo: {           // Reverse Post Order
	cfg::ReversePostOrderTraversal RPOT(M);
	copy(RPOT.begin(), RPOT.end(),
	     ostream_iterator<BasicBlock*>(*Out, "\n"));
	break;
      }
      default:
	abort();
	break;
      }
    }
  }
  delete C;

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