Add llvm-modextract tool.

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.

Differential Revision: https://reviews.llvm.org/D26778

llvm-svn: 288201

1 files changed, 72 insertions, 0 deletions

diff --git a/llvm/tools/llvm-modextract/llvm-modextract.cpp b/llvm/tools/llvm-modextract/llvm-modextract.cpp
new file mode 100644
index 00000000000..b4279f2ab1e
--- /dev/null
+++ b/llvm/tools/llvm-modextract/llvm-modextract.cpp
@@ -0,0 +1,72 @@
+//===-- llvm-modextract.cpp - LLVM module extractor utility ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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<tool_output_file> Out(
+      new tool_output_file(OutputFilename, EC, sys::fs::F_None));
+  ExitOnErr(errorCodeToError(EC));
+
+  if (BinaryExtract) {
+    SmallVector<char, 0> Header;
+    BitcodeWriter Writer(Header);
+    Out->os() << Header << Ms[ModuleIndex].getBuffer();
+    return 0;
+  }
+
+  std::unique_ptr<Module> M = ExitOnErr(Ms[ModuleIndex].parseModule(Context));
+  WriteBitcodeToFile(M.get(), Out->os());
+
+  return 0;
+}