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/MemoryBuffer.h"
21#include "llvm/Support/ToolOutputFile.h"
22#include "llvm/Support/WithColor.h"
23
24using namespace llvm;
25
26static cl::OptionCategory ModextractCategory("Modextract Options");
27
28static cl::opt<bool>
29    BinaryExtract("b", cl::desc("Whether to perform binary extraction"),
30                  cl::cat(ModextractCategory));
31
32static cl::opt<std::string> OutputFilename("o", cl::Required,
33                                           cl::desc("Output filename"),
34                                           cl::value_desc("filename"),
35                                           cl::cat(ModextractCategory));
36
37static cl::opt<std::string> InputFilename(cl::Positional,
38                                          cl::desc("<input bitcode>"),
39                                          cl::init("-"),
40                                          cl::cat(ModextractCategory));
41
42static cl::opt<unsigned> ModuleIndex("n", cl::Required,
43                                     cl::desc("Index of module to extract"),
44                                     cl::value_desc("index"),
45                                     cl::cat(ModextractCategory));
46
47int main(int argc, char **argv) {
48  cl::HideUnrelatedOptions({&ModextractCategory, &getColorCategory()});
49  cl::ParseCommandLineOptions(argc, argv, "Module extractor");
50
51  ExitOnError ExitOnErr("llvm-modextract: error: ");
52
53  std::unique_ptr<MemoryBuffer> MB =
54      ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
55  std::vector<BitcodeModule> Ms = ExitOnErr(getBitcodeModuleList(*MB));
56
57  LLVMContext Context;
58  if (ModuleIndex >= Ms.size()) {
59    errs() << "llvm-modextract: error: module index out of range; bitcode file "
60              "contains "
61           << Ms.size() << " module(s)\n";
62    return 1;
63  }
64
65  std::error_code EC;
66  std::unique_ptr<ToolOutputFile> Out(
67      new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
68  ExitOnErr(errorCodeToError(EC));
69
70  if (BinaryExtract) {
71    SmallVector<char, 0> Result;
72    BitcodeWriter Writer(Result);
73    Result.append(Ms[ModuleIndex].getBuffer().begin(),
74                  Ms[ModuleIndex].getBuffer().end());
75    Writer.copyStrtab(Ms[ModuleIndex].getStrtab());
76    Out->os() << Result;
77    Out->keep();
78    return 0;
79  }
80
81  std::unique_ptr<Module> M = ExitOnErr(Ms[ModuleIndex].parseModule(Context));
82  WriteBitcodeToFile(*M, Out->os());
83
84  Out->keep();
85  return 0;
86}
87