llvm-dis.cpp revision 195340 
1//===-- llvm-dis.cpp - The low-level LLVM disassembler --------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This utility may be invoked in the following manner:
11//  llvm-dis [options]      - Read LLVM bitcode from stdin, write asm to stdout
12//  llvm-dis [options] x.bc - Read LLVM bitcode from the x.bc file, write asm
13//                            to the x.ll file.
14//  Options:
15//      --help   - Output information about command line switches
16//
17//===----------------------------------------------------------------------===//
18
19#include "llvm/LLVMContext.h"
20#include "llvm/Module.h"
21#include "llvm/PassManager.h"
22#include "llvm/Bitcode/ReaderWriter.h"
23#include "llvm/Assembly/PrintModulePass.h"
24#include "llvm/Support/CommandLine.h"
25#include "llvm/Support/ManagedStatic.h"
26#include "llvm/Support/MemoryBuffer.h"
27#include "llvm/Support/PrettyStackTrace.h"
28#include "llvm/Support/Streams.h"
29#include "llvm/Support/raw_ostream.h"
30#include "llvm/System/Signals.h"
31#include <iostream>
32#include <fstream>
33#include <memory>
34using namespace llvm;
35
36static cl::opt<std::string>
37InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
38
39static cl::opt<std::string>
40OutputFilename("o", cl::desc("Override output filename"),
41               cl::value_desc("filename"));
42
43static cl::opt<bool>
44Force("f", cl::desc("Overwrite output files"));
45
46static cl::opt<bool>
47DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
48
49int main(int argc, char **argv) {
50  // Print a stack trace if we signal out.
51  sys::PrintStackTraceOnErrorSignal();
52  PrettyStackTraceProgram X(argc, argv);
53
54  LLVMContext Context;
55  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
56  try {
57    cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
58
59    std::ostream *Out = &std::cout;  // Default to printing to stdout.
60    std::string ErrorMessage;
61
62    std::auto_ptr<Module> M;
63
64    if (MemoryBuffer *Buffer
65           = MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage)) {
66      M.reset(ParseBitcodeFile(Buffer, Context, &ErrorMessage));
67      delete Buffer;
68    }
69
70    if (M.get() == 0) {
71      cerr << argv[0] << ": ";
72      if (ErrorMessage.size())
73        cerr << ErrorMessage << "\n";
74      else
75        cerr << "bitcode didn't read correctly.\n";
76      return 1;
77    }
78
79    if (DontPrint) {
80      // Just use stdout.  We won't actually print anything on it.
81    } else if (OutputFilename != "") {   // Specified an output filename?
82      if (OutputFilename != "-") { // Not stdout?
83        if (!Force && std::ifstream(OutputFilename.c_str())) {
84          // If force is not specified, make sure not to overwrite a file!
85          cerr << argv[0] << ": error opening '" << OutputFilename
86               << "': file exists! Sending to standard output.\n";
87        } else {
88          Out = new std::ofstream(OutputFilename.c_str());
89        }
90      }
91    } else {
92      if (InputFilename == "-") {
93        OutputFilename = "-";
94      } else {
95        std::string IFN = InputFilename;
96        int Len = IFN.length();
97        if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
98          // Source ends in .bc
99          OutputFilename = std::string(IFN.begin(), IFN.end()-3)+".ll";
100        } else {
101          OutputFilename = IFN+".ll";
102        }
103
104        if (!Force && std::ifstream(OutputFilename.c_str())) {
105          // If force is not specified, make sure not to overwrite a file!
106          cerr << argv[0] << ": error opening '" << OutputFilename
107               << "': file exists! Sending to standard output.\n";
108        } else {
109          Out = new std::ofstream(OutputFilename.c_str());
110
111          // Make sure that the Out file gets unlinked from the disk if we get a
112          // SIGINT
113          sys::RemoveFileOnSignal(sys::Path(OutputFilename));
114        }
115      }
116    }
117
118    if (!Out->good()) {
119      cerr << argv[0] << ": error opening " << OutputFilename
120           << ": sending to stdout instead!\n";
121      Out = &std::cout;
122    }
123
124    // All that llvm-dis does is write the assembly to a file.
125    if (!DontPrint) {
126      PassManager Passes;
127      raw_os_ostream L(*Out);
128      Passes.add(createPrintModulePass(&L));
129      Passes.run(*M.get());
130    }
131
132    if (Out != &std::cout) {
133      ((std::ofstream*)Out)->close();
134      delete Out;
135    }
136    return 0;
137  } catch (const std::string& msg) {
138    cerr << argv[0] << ": " << msg << "\n";
139  } catch (...) {
140    cerr << argv[0] << ": Unexpected unknown exception occurred.\n";
141  }
142
143  return 1;
144}
145
146