Report fatal translator errors to the browser

tools/pnacl-llc/SRPCStreamer.cpp

Index: tools/pnacl-llc/SRPCStreamer.cpp
diff --git a/tools/pnacl-llc/SRPCStreamer.cpp b/tools/pnacl-llc/SRPCStreamer.cpp
index e6546aef5f601eeb9c51cb8aba49c61bcb221486..ddec846d2c915a9d6a90874bb1595e3901c62435 100644
--- a/tools/pnacl-llc/SRPCStreamer.cpp
+++ b/tools/pnacl-llc/SRPCStreamer.cpp
@@ -119,19 +119,30 @@ llvm::DataStreamer *SRPCStreamer::init(void *(*Callback)(void *), void *arg,
 }
 
 size_t SRPCStreamer::gotChunk(unsigned char *bytes, size_t len) {
-  if (Error) return 0;
+  if (__sync_fetch_and_add(&Error, 0)) return 0; // Atomic read.

[jvoung (off chromium), 2013/09/09 23:47:53]

Hmm hopefully an add of 0 doesn't get optimized out =)

   return Q.PutBytes(bytes, len);
 }
 
 int SRPCStreamer::streamEnd(std::string *ErrMsg) {
   Q.SetDone();
   int err = pthread_join(CompileThread, NULL);
-  if (err) {
+  __sync_synchronize();

[jvoung (off chromium), 2013/09/09 23:47:53]

Does pthread_join form a happens-before edge?  Do we need the
__sync_synchronize?

+  if (Error) {
+    if (ErrMsg)
+      *ErrMsg = std::string("PNaCl Translator Error: " + ErrorMessage);
+    return 1;
+  } else if (err) {
     if (ErrMsg) *ErrMsg = std::string(strerror(errno));
     return err;
   }
-  if (Error && ErrMsg) *ErrMsg = std::string("compile failed.");
-  return Error;
+  return 0;
+}
+
+void SRPCStreamer::setFatalError(const std::string& message) {
+  __sync_fetch_and_add(&Error, 1);
+  ErrorMessage = message;
+  __sync_synchronize();
+  pthread_exit(NULL);
 }
 
 #endif // __native_client__