Copy Bitwriter to generate PNaClBitwriter.

tools/pnacl-freeze/pnacl-freeze.cpp

+/* Copyright 2013 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can
+ * be found in the LICENSE file.
+ */
+
+//===-- pnacl-freeze.cpp - The low-level PNaCl bitcode freezer     --------===//
+//
+//===----------------------------------------------------------------------===//
+//
+// Generates PNaCl pexe wire format.
+//
+// This utility may be invoked in the following manner:
+//     pnacl-freeze [options] <pexe file>
+
+//  Options:
+//      -help         - Output information about command line switches

[jvoung (off chromium), 2013/04/25 17:42:45]

Probably don't need to put the commandline usage here, since all the tools have
-help, etc...

[Karl, 2013/04/25 20:48:17]

Done.

[Karl, 2013/04/25 20:48:17]

Done.

+//      -o=<filename> - Specify output filename
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Assembly/AssemblyAnnotationWriter.h"
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+#include "llvm/Bitcode/ReaderWriter.h"

[jvoung (off chromium), 2013/04/25 17:42:45]

Perhaps add a TODO that it should only use one of the ReaderWriter headers later
(not both the NaCl and non-NaCl?)?

[Karl, 2013/04/25 20:48:17]

This can't be done. We need stuff in ReaderWriter for the bitreader, and stuff
in NaClReaderWriter for the naclbitwriter.

Added comments to clarify this.

+#include "llvm/DebugInfo.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/ToolOutputFile.h"
+#include "llvm/Support/system_error.h"
+
+// llvm/Bitcode/BitstreamWriter.h
+
+using namespace llvm;
+
+
+static cl::opt<std::string>
+OutputFilename("o", cl::desc("Specify output filename"), cl::value_desc("filename"));

[jvoung (off chromium), 2013/04/25 17:42:45]

80 col

[Karl, 2013/04/25 20:48:17]

Done.

+
+static cl::opt<std::string>
+InputFilename(cl::Positional, cl::desc("<pexe file>"), cl::Required);
+
+static void WriteOutputFile(const Module *M) {
+
+  std::string FrozenFilename =
+    (OutputFilename.size() == 0 ? (InputFilename + ".frozen") : OutputFilename);

[jvoung (off chromium), 2013/04/25 17:42:45]

Does this mean we can't do "pnacl-freeze input.pexe -o - | pnacl-thaw" and
compare the output of the thaw to input.pexe?

[Karl, 2013/04/25 20:48:17]

Note that pnacl-thaw is only for command line usage. I expect pnacl-translate to
be modified to use the NaCl Bitcode Reader so that it can directly thaw the wire
format file as it is read.

Part of the problem is to figure out how pnacl-freeze fits into the build
stream. If we are using it as a post-step, it would overwrite input.pexe.

It is true that at the moment, I only allow the API to update a file, and hence
"-o -" is not possible.

I would add your option, but I don't know how to convert stdout into a
'raw_fd_ostream::F_Binary' stream (see Out below). Hence, I don't know how to
allow this.

[jvoung (off chromium), 2013/04/25 22:25:36]

Ok, just wondering if handling that like the other tools would help with
testing.

+
+  std::string ErrorInfo;
+  OwningPtr<tool_output_file> Out
+  (new tool_output_file(FrozenFilename.c_str(), ErrorInfo,

[jvoung (off chromium), 2013/04/25 17:42:45]

is the style supposed to indent the (new...)?

[Karl, 2013/04/25 20:48:17]

I followed the style from llvm-as (i.e. I copied llvm-as.cpp and edited it).
However, I don't see any problem with indenting, so I'll indent it.

+                        raw_fd_ostream::F_Binary));
+  if (!ErrorInfo.empty()) {
+    errs() << ErrorInfo << '\n';
+    exit(1);
+  }
+
+  PNaClWriteBitcodeToFile(M, Out->os());
+
+  // Declare success.
+  Out->keep();
+}
+
+int main(int argc, char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+
+  LLVMContext &Context = getGlobalContext();
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+  cl::ParseCommandLineOptions(argc, argv, "Generates PNaCl pexe wire format\n");
+
+  std::string ErrorMessage;
+  std::auto_ptr<Module> M;
+
+  // Use the bitcode streaming interface
+  DataStreamer *streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
+  if (streamer) {
+    std::string DisplayFilename = InputFilename;
+    M.reset(getStreamedBitcodeModule(DisplayFilename, streamer, Context,
+                                     &ErrorMessage));
+    if(M.get() != 0 && M->MaterializeAllPermanently(&ErrorMessage)) {
+      M.reset();
+    }
+  }
+
+  if (M.get() == 0) {
+    errs() << argv[0] << ": ";
+    if (ErrorMessage.size())
+      errs() << ErrorMessage << "\n";
+    else
+      errs() << "bitcode didn't read correctly.\n";
+    return 1;
+  }
+
+  WriteOutputFile(M.get());
+  return 0;
+}