Allow pnacl-freeze/thaw to redirect to stdin/stdout.

tools/pnacl-thaw/pnacl-thaw.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-thaw.cpp - The low-level NaCl bitcode thawer ----------------===//
 //
 //===----------------------------------------------------------------------===//
 //
 // Converts NaCl wire format back to LLVM bitcode.
@@ skipping 15 matching lines @@
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ToolOutputFile.h"
 
 using namespace llvm;
 
 static cl::opt<std::string>
 OutputFilename("o", cl::desc("Specify thawed pexe filename"),
                cl::value_desc("filename"));
 
 static cl::opt<std::string>
-InputFilename(cl::Positional, cl::desc("<frozen file>"), cl::Required);
+InputFilename(cl::Positional, cl::desc("<frozen file>"), cl::init("-"));
 
 static void WriteOutputFile(const Module *M) {
 
-  std::string ThawedFilename =
-    (OutputFilename.size() == 0 ? (InputFilename + ".thawed") : OutputFilename);
+  std::string ThawedFilename(OutputFilename);
+  if (OutputFilename.size() == 0) {
+    std::string input_filename;
+    if (InputFilename == "-")
+      input_filename = "<stdin>";
+    else
+      input_filename = InputFilename;
+    ThawedFilename = input_filename + ".thawed";
+  }
 
   std::string ErrorInfo;
   OwningPtr<tool_output_file> Out
     (new tool_output_file(ThawedFilename.c_str(), ErrorInfo,
                           raw_fd_ostream::F_Binary));
   if (!ErrorInfo.empty()) {
     errs() << ErrorInfo << '\n';
     exit(1);
   }
 
@@ skipping 13 matching lines @@
 
   cl::ParseCommandLineOptions(
       argc, argv, "Converts NaCl pexe wire format into LLVM bitcode 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;
+    std::string DisplayFilename;
+    if (InputFilename == "-")
+      DisplayFilename = "<stdin>";
+    else
+      DisplayFilename = InputFilename;
     M.reset(getNaClStreamedBitcodeModule(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;
 }