tools/llvm-cat/llvm-cat.cpp

   1 //===- llvm-cat.cpp - LLVM module concatenation 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 list of input modules and uses them to create a multi-module
  11 // bitcode file.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/ADT/SmallVector.h"
  16 #include "llvm/Bitcode/BitcodeReader.h"
  17 #include "llvm/Bitcode/BitcodeWriter.h"
  18 #include "llvm/IR/LLVMContext.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/IRReader/IRReader.h"
  21 #include "llvm/Support/CommandLine.h"
  22 #include "llvm/Support/Error.h"
  23 #include "llvm/Support/FileSystem.h"
  24 #include "llvm/Support/MemoryBuffer.h"
  25 #include "llvm/Support/SourceMgr.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <algorithm>
  28 #include <memory>
  29 #include <string>
  30 #include <system_error>
  31 #include <vector>
  32
  33 using namespace llvm;
  34
  35 cl::OptionCategory CatCategory("llvm-cat Options");
  36
  37 static cl::opt<bool>
  38     BinaryCat("b", cl::desc("Whether to perform binary concatenation"),
  39               cl::cat(CatCategory));
  40
  41 static cl::opt<std::string> OutputFilename("o", cl::Required,
  42                                            cl::desc("Output filename"),
  43                                            cl::value_desc("filename"),
  44                                            cl::cat(CatCategory));
  45
  46 static cl::list<std::string> InputFilenames(cl::Positional, cl::ZeroOrMore,
  47                                             cl::desc("<input  files>"),
  48                                             cl::cat(CatCategory));
  49
  50 int main(int argc, char **argv) {
  51   cl::HideUnrelatedOptions(CatCategory);
  52   cl::ParseCommandLineOptions(argc, argv, "Module concatenation");
  53
  54   ExitOnError ExitOnErr("llvm-cat: ");
  55   LLVMContext Context;
  56
  57   SmallVector<char, 0> Buffer;
  58   BitcodeWriter Writer(Buffer);
  59   if (BinaryCat) {
  60     for (const auto &InputFilename : InputFilenames) {
  61       std::unique_ptr<MemoryBuffer> MB = ExitOnErr(
  62           errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
  63       std::vector<BitcodeModule> Mods = ExitOnErr(getBitcodeModuleList(*MB));
  64       for (auto &BitcodeMod : Mods) {
  65         Buffer.insert(Buffer.end(), BitcodeMod.getBuffer().begin(),
  66                       BitcodeMod.getBuffer().end());
  67         Writer.copyStrtab(BitcodeMod.getStrtab());
  68       }
  69     }
  70   } else {
  71     // The string table does not own strings added to it, some of which are
  72     // owned by the modules; keep them alive until we write the string table.
  73     std::vector<std::unique_ptr<Module>> OwnedMods;
  74     for (const auto &InputFilename : InputFilenames) {
  75       SMDiagnostic Err;
  76       std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
  77       if (!M) {
  78         Err.print(argv[0], errs());
  79         return 1;
  80       }
  81       Writer.writeModule(*M);
  82       OwnedMods.push_back(std::move(M));
  83     }
  84     Writer.writeStrtab();
  85   }
  86
  87   std::error_code EC;
  88   raw_fd_ostream OS(OutputFilename, EC, sys::fs::OpenFlags::OF_None);
  89   if (EC) {
  90     errs() << argv[0] << ": cannot open " << OutputFilename << " for writing: "
  91            << EC.message();
  92     return 1;
  93   }
  94
  95   OS.write(Buffer.data(), Buffer.size());
  96   return 0;
  97 }