llvm/tools/llvm-modextract/llvm-modextract.cpp

   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
  24 using namespace llvm;
  25
  26 static cl::OptionCategory ModextractCategory("Modextract Options");
  27
  28 static cl::opt<bool>
  29     BinaryExtract("b", cl::desc("Whether to perform binary extraction"),
  30                   cl::cat(ModextractCategory));
  31
  32 static cl::opt<std::string> OutputFilename("o", cl::Required,
  33                                            cl::desc("Output filename"),
  34                                            cl::value_desc("filename"),
  35                                            cl::cat(ModextractCategory));
  36
  37 static cl::opt<std::string> InputFilename(cl::Positional,
  38                                           cl::desc("<input bitcode>"),
  39                                           cl::init("-"),
  40                                           cl::cat(ModextractCategory));
  41
  42 static 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
  47 int 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 }