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(Val: "-"),
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(Categories: {&ModextractCategory, &getColorCategory()});
49 cl::ParseCommandLineOptions(argc, argv, Overview: "Module extractor");
50
51 ExitOnError ExitOnErr("llvm-modextract: error: ");
52
53 std::unique_ptr<MemoryBuffer> MB =
54 ExitOnErr(errorOrToExpected(EO: MemoryBuffer::getFileOrSTDIN(Filename: InputFilename)));
55 std::vector<BitcodeModule> Ms = ExitOnErr(getBitcodeModuleList(Buffer: *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(in_start: Ms[ModuleIndex].getBuffer().begin(),
74 in_end: Ms[ModuleIndex].getBuffer().end());
75 Writer.copyStrtab(Strtab: 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: *M, Out&: Out->os());
83
84 Out->keep();
85 return 0;
86}
87

source code of llvm/tools/llvm-modextract/llvm-modextract.cpp