1//===-- llvm-modextract.cpp - LLVM module extractor utility ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This program is for testing features that rely on multi-module bitcode files.
10// It takes a multi-module bitcode file, extracts one of the modules and writes
11// it to the output file.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Bitcode/BitcodeReader.h"
16#include "llvm/Bitcode/BitcodeWriter.h"
17#include "llvm/Support/CommandLine.h"
18#include "llvm/Support/Error.h"
19#include "llvm/Support/FileSystem.h"
20#include "llvm/Support/ToolOutputFile.h"
21
22using namespace llvm;
23
24static cl::opt<bool>
25    BinaryExtract("b", cl::desc("Whether to perform binary extraction"));
26
27static cl::opt<std::string> OutputFilename("o", cl::Required,
28                                           cl::desc("Output filename"),
29                                           cl::value_desc("filename"));
30
31static cl::opt<std::string>
32    InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
33
34static cl::opt<unsigned> ModuleIndex("n", cl::Required,
35                                     cl::desc("Index of module to extract"),
36                                     cl::value_desc("index"));
37
38int main(int argc, char **argv) {
39  cl::ParseCommandLineOptions(argc, argv, "Module extractor");
40
41  ExitOnError ExitOnErr("llvm-modextract: error: ");
42
43  std::unique_ptr<MemoryBuffer> MB =
44      ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
45  std::vector<BitcodeModule> Ms = ExitOnErr(getBitcodeModuleList(*MB));
46
47  LLVMContext Context;
48  if (ModuleIndex >= Ms.size()) {
49    errs() << "llvm-modextract: error: module index out of range; bitcode file "
50              "contains "
51           << Ms.size() << " module(s)\n";
52    return 1;
53  }
54
55  std::error_code EC;
56  std::unique_ptr<ToolOutputFile> Out(
57      new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
58  ExitOnErr(errorCodeToError(EC));
59
60  if (BinaryExtract) {
61    SmallVector<char, 0> Result;
62    BitcodeWriter Writer(Result);
63    Result.append(Ms[ModuleIndex].getBuffer().begin(),
64                  Ms[ModuleIndex].getBuffer().end());
65    Writer.copyStrtab(Ms[ModuleIndex].getStrtab());
66    Out->os() << Result;
67    Out->keep();
68    return 0;
69  }
70
71  std::unique_ptr<Module> M = ExitOnErr(Ms[ModuleIndex].parseModule(Context));
72  WriteBitcodeToFile(*M, Out->os());
73
74  Out->keep();
75  return 0;
76}
77