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

tools/pnacl-freeze/pnacl-freeze.cpp

Index: tools/pnacl-freeze/pnacl-freeze.cpp
diff --git a/tools/pnacl-freeze/pnacl-freeze.cpp b/tools/pnacl-freeze/pnacl-freeze.cpp
index 963000a714a5063d224e00bc328348bcd343eba1..694284198c7f8efb20eb54f85a9910cd969c12d6 100644
--- a/tools/pnacl-freeze/pnacl-freeze.cpp
+++ b/tools/pnacl-freeze/pnacl-freeze.cpp
@@ -34,12 +34,19 @@ OutputFilename("o", cl::desc("Specify output filename"),
 	       cl::value_desc("filename"));
 
 static cl::opt<std::string>
-InputFilename(cl::Positional, cl::desc("<pexe file>"), cl::Required);
+InputFilename(cl::Positional, cl::desc("<pexe file>"), cl::init("-"));
 
 static void WriteOutputFile(const Module *M) {
 
-  std::string FrozenFilename =
-    (OutputFilename.size() == 0 ? (InputFilename + ".frozen") : OutputFilename);
+  std::string FrozenFilename(OutputFilename);
+  if (OutputFilename.size() == 0) {
+    std::string input_filename;
+    if (InputFilename == "-")
+      input_filename = "<stdin>";

[jvoung (off chromium), 2013/05/02 22:12:50]

What some of the other tools do is set OutputFilename to be "-" also, in the
case Input is "-" and Output is not specified.  That might be simpler than this,
since this would leave a file with funny characters "<stdin>.frozen" in its
name?

[Karl, 2013/05/06 16:21:51]

I guess this is ok. I just have to redirect my mind to think in terms of pipes.
Changing.

+    else
+      input_filename = InputFilename;
+    FrozenFilename = input_filename + ".frozen";
+  }
 
   std::string ErrorInfo;
   OwningPtr<tool_output_file> Out
@@ -72,7 +79,11 @@ int main(int argc, char **argv) {
   // 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(getStreamedBitcodeModule(DisplayFilename, streamer, Context,
                                      &ErrorMessage));
     if(M.get() != 0 && M->MaterializeAllPermanently(&ErrorMessage)) {