llvm-cat.cpp

//===- llvm-cat.cpp - LLVM module concatenation utility -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This program is for testing features that rely on multi-module bitcode files.
// It takes a list of input modules and uses them to create a multi-module
// bitcode file.
//
//===----------------------------------------------------------------------===//

#include"llvm/ADT/SmallVector.h"
#include"llvm/Bitcode/BitcodeReader.h"
#include"llvm/Bitcode/BitcodeWriter.h"
#include"llvm/IR/LLVMContext.h"
#include"llvm/IR/Module.h"
#include"llvm/IRReader/IRReader.h"
#include"llvm/Support/CommandLine.h"
#include"llvm/Support/Error.h"
#include"llvm/Support/FileSystem.h"
#include"llvm/Support/MemoryBuffer.h"
#include"llvm/Support/SourceMgr.h"
#include"llvm/Support/raw_ostream.h"
#include<algorithm>
#include<memory>
#include<string>
#include<system_error>
#include<vector>

usingnamespacellvm;

cl::OptionCategory CatCategory("llvm-cat Options");

static cl::opt<bool>
BinaryCat("b", cl::desc("Whether to perform binary concatenation"),
 cl::cat(CatCategory));

static cl::opt<std::string> OutputFilename("o", cl::Required,
cl::desc("Output filename"),
 cl::value_desc("filename"),
 cl::cat(CatCategory));

static cl::list<std::string> InputFilenames(cl::Positional,
cl::desc("<input files>"),
 cl::cat(CatCategory));

intmain(int argc, char **argv) {
cl::HideUnrelatedOptions(CatCategory);
cl::ParseCommandLineOptions(argc, argv, "Module concatenation");

 ExitOnError ExitOnErr("llvm-cat: ");
 LLVMContext Context;

 SmallVector<char, 0> Buffer;
 BitcodeWriter Writer(Buffer);
if (BinaryCat) {
for (constauto &InputFilename : InputFilenames) {
 std::unique_ptr<MemoryBuffer> MB = ExitOnErr(
errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
 std::vector<BitcodeModule> Mods = ExitOnErr(getBitcodeModuleList(*MB));
for (auto &BitcodeMod : Mods) {
llvm::append_range(Buffer, BitcodeMod.getBuffer());
 Writer.copyStrtab(BitcodeMod.getStrtab());
 }
 }
 } else {
// The string table does not own strings added to it, some of which are
// owned by the modules; keep them alive until we write the string table.
 std::vector<std::unique_ptr<Module>> OwnedMods;
for (constauto &InputFilename : InputFilenames) {
 SMDiagnostic Err;
 std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
if (!M) {
 Err.print(argv[0], errs());
return1;
 }
 Writer.writeModule(*M);
 OwnedMods.push_back(std::move(M));
 }
 Writer.writeStrtab();
 }

 std::error_code EC;
 raw_fd_ostream OS(OutputFilename, EC, sys::fs::OpenFlags::OF_None);
if (EC) {
errs() << argv[0] << ": cannot open " << OutputFilename << " for writing: "
 << EC.message();
return1;
 }

 OS.write(Buffer.data(), Buffer.size());
return0;
}