Add an option to dump core when an uncaught exception is thrown.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 632ecdc50a32b569ba3224c9428a165ef10deccb..1d390401ef8f1e4f5d5b1cc0dde2674e55a1f855 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1198,6 +1198,7 @@ bool Isolate::IsErrorObject(Handle<Object> obj) {
   return false;
 }
 
+static int fatal_exception_depth = 0;
 
 void Isolate::DoThrow(Object* exception, MessageLocation* location) {
   ASSERT(!has_pending_exception());
@@ -1281,6 +1282,20 @@ void Isolate::DoThrow(Object* exception, MessageLocation* location) {
         thread_local_top()->pending_message_start_pos_ = location->start_pos();
         thread_local_top()->pending_message_end_pos_ = location->end_pos();
       }
+
+      // If the abort-on-uncaught-exception flag is specified, abort on any
+      // exception not caught by JavaScript, even when an external handler is
+      // present.  This flag is intended for use by JavaScript developers, so
+      // print a user-friendly stack trace (not an internal one).
+      if (fatal_exception_depth == 0 &&
+          FLAG_abort_on_uncaught_exception &&
+          (report_exception || can_be_caught_externally)) {
+        fatal_exception_depth++;
+        fprintf(stderr, "%s\n\nFROM\n",
+          *MessageHandler::GetLocalizedMessage(this, message_obj));
+        PrintCurrentStackTrace(stderr);
+        OS::Abort();
+      }
     } else if (location != NULL && !location->script().is_null()) {
       // We are bootstrapping and caught an error where the location is set
       // and we have a script for the location.