Reverted r576 as it caused a regression.

src/top.h

 // Copyright 2006-2008 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 35 matching lines @@
   // lookups.
   Context* context_;
   Object* pending_exception_;
   // Use a separate value for scheduled exceptions to preserve the
   // invariants that hold about pending_exception.  We may want to
   // unify them later.
   Object* scheduled_exception_;
   bool external_caught_exception_;
   v8::TryCatch* try_catch_handler_;
   SaveContext* save_context_;
-  // Flag indicating that the try_catch_handler_ contains an exception to be
-  // caught.
-  bool pending_external_caught_exception_;
+  v8::TryCatch* catcher_;
 
   // Stack.
   Address c_entry_fp_;  // the frame pointer of the top c entry frame
   Address handler_;   // try-blocks are chained through the stack
   bool stack_is_cooked_;
   inline bool stack_is_cooked() { return stack_is_cooked_; }
   inline void set_stack_is_cooked(bool value) { stack_is_cooked_ = value; }
 
   // Generated code scratch locations.
   int32_t formal_count_;
@@ skipping 70 matching lines @@
     ASSERT(has_scheduled_exception());
     return thread_local_.scheduled_exception_;
   }
   static bool has_scheduled_exception() {
     return !thread_local_.scheduled_exception_->IsTheHole();
   }
   static void clear_scheduled_exception() {
     thread_local_.scheduled_exception_ = Heap::the_hole_value();
   }
 
-  // Propagate the external caught exception flag. If there is no external
-  // caught exception always clear the TryCatch handler as it might contain
-  // an exception object from a throw which was bypassed by a finally block
-  // doing an explicit return/break/continue.
-  static void propagate_external_caught() {
-    if (has_pending_exception()) {
-      thread_local_.external_caught_exception_ =
-          thread_local_.pending_external_caught_exception_;
-    } else {
-      if (thread_local_.try_catch_handler_ != NULL) {
-        thread_local_.try_catch_handler_->Reset();
-      }
-    }
-    thread_local_.pending_external_caught_exception_ = false;
+  static void setup_external_caught() {
+    thread_local_.external_caught_exception_ =
+        (thread_local_.catcher_ != NULL) &&
+        (Top::thread_local_.try_catch_handler_ == Top::thread_local_.catcher_);
   }
 
   // Tells whether the current context has experienced an out of memory
   // exception.
   static bool is_out_of_memory();
 
   // JS execution stack (see frames.h).
   static Address c_entry_fp(ThreadLocalTop* thread) {
     return thread->c_entry_fp_;
   }
@@ skipping 193 matching lines @@
 
 class ExecutionAccess BASE_EMBEDDED {
  public:
   ExecutionAccess();
   ~ExecutionAccess();
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_TOP_H_