tools/llvm-modextract/llvm-modextract.cpp

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