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

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1180 matching lines @@
   for (Object* prototype = *obj; !prototype->IsNull();
        prototype = prototype->GetPrototype(this)) {
     if (!prototype->IsJSObject()) return false;
     if (JSObject::cast(prototype)->map()->constructor() == error_constructor) {
       return true;
     }
   }
   return false;
 }
 
+static int fatal_exception_depth = 0;
 
 void Isolate::DoThrow(Object* exception, MessageLocation* location) {
   ASSERT(!has_pending_exception());
 
   HandleScope scope(this);
   Handle<Object> exception_handle(exception, this);
 
   // Determine reporting and whether the exception is caught externally.
   bool catchable_by_javascript = is_catchable_by_javascript(exception);
   bool can_be_caught_externally = false;
@@ skipping 63 matching lines @@
           location,
           HandleVector<Object>(&exception_arg, 1),
           stack_trace,
           stack_trace_object);
       thread_local_top()->pending_message_obj_ = *message_obj;
       if (location != NULL) {
         thread_local_top()->pending_message_script_ = *location->script();
         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, "UNCAUGHT EXCEPTION: ");
+        exception->ShortPrint(stderr);
+
+        if (IsErrorObject(exception_handle)) {
+          Handle<String> key = factory()->InternalizeOneByteString(
+              STATIC_ASCII_VECTOR("message"));
+          MaybeObject *maybeMessage =
+            JSObject::cast(*exception_handle)->GetProperty(*key);
+          Object *messageObject;
+          if (maybeMessage->ToObject(&messageObject)) {
+            String *message = String::cast(messageObject);
+            fprintf(stderr, "\nEXCEPTION MESSAGE: ");
+            message->PrintOn(stderr);
+          }
+        }

[Yang, 2013/04/02 10:42:30]

I was actually suggesting to replace the entire above if-block with
MessageHandler::DefaultMessageReport(this, location, message_obj);

That would print

test.js:86: Uncaught Error: my sample error

FROM:
baz (test.js:13:9)
bar (test.js:8:2)
foo (test.js:3:5)
test.js:16:1


As opposed to

UNCAUGHT EXCEPTION: 0x3f716a49 <an Error>
EXCEPTION MESSAGE: my sample error
FROM:
baz (test.js:13:9)
bar (test.js:8:2)
foo (test.js:3:5)
test.js:16:1


I just prefer using existing code that essentially prints the same content
(unless you insist on the Error object's address, in which case you could keep
the ShortPrint).

+
+        fprintf(stderr, "\nFROM:\n");
+        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.
       // In this case we could have an extension (or an internal error
       // somewhere) and we print out the line number at which the error occured
       // to the console for easier debugging.
       int line_number = GetScriptLineNumberSafe(location->script(),
                                                 location->start_pos());
       if (exception->IsString()) {
         OS::PrintError(
@@ skipping 1071 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal