--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/llvm-modextract/llvm-modextract.cpp	Mon May 25 11:07:02 2020 +0900
@@ -0,0 +1,76 @@
+//===-- llvm-modextract.cpp - LLVM module extractor 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 multi-module bitcode file, extracts one of the modules and writes
+// it to the output file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Bitcode/BitcodeWriter.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+using namespace llvm;
+
+static cl::opt<bool>
+    BinaryExtract("b", cl::desc("Whether to perform binary extraction"));
+
+static cl::opt<std::string> OutputFilename("o", cl::Required,
+                                           cl::desc("Output filename"),
+                                           cl::value_desc("filename"));
+
+static cl::opt<std::string>
+    InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
+
+static cl::opt<unsigned> ModuleIndex("n", cl::Required,
+                                     cl::desc("Index of module to extract"),
+                                     cl::value_desc("index"));
+
+int main(int argc, char **argv) {
+  cl::ParseCommandLineOptions(argc, argv, "Module extractor");
+
+  ExitOnError ExitOnErr("llvm-modextract: error: ");
+
+  std::unique_ptr<MemoryBuffer> MB =
+      ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
+  std::vector<BitcodeModule> Ms = ExitOnErr(getBitcodeModuleList(*MB));
+
+  LLVMContext Context;
+  if (ModuleIndex >= Ms.size()) {
+    errs() << "llvm-modextract: error: module index out of range; bitcode file "
+              "contains "
+           << Ms.size() << " module(s)\n";
+    return 1;
+  }
+
+  std::error_code EC;
+  std::unique_ptr<ToolOutputFile> Out(
+      new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
+  ExitOnErr(errorCodeToError(EC));
+
+  if (BinaryExtract) {
+    SmallVector<char, 0> Result;
+    BitcodeWriter Writer(Result);
+    Result.append(Ms[ModuleIndex].getBuffer().begin(),
+                  Ms[ModuleIndex].getBuffer().end());
+    Writer.copyStrtab(Ms[ModuleIndex].getStrtab());
+    Out->os() << Result;
+    Out->keep();
+    return 0;
+  }
+
+  std::unique_ptr<Module> M = ExitOnErr(Ms[ModuleIndex].parseModule(Context));
+  WriteBitcodeToFile(*M, Out->os());
+
+  Out->keep();
+  return 0;
+}