In Isolate::Throw, call PredictExceptionCatcher only if necessary.

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 1125 matching lines @@
     } else {
       Handle<Object> message_obj = CreateMessage(exception_handle, location);
       thread_local_top()->pending_message_obj_ = *message_obj;
 
       // For any exception not caught by JavaScript, even when an external
       // handler is present:
       // If the abort-on-uncaught-exception flag is specified, and if the
       // embedder didn't specify a custom uncaught exception callback,
       // or if the custom callback determined that V8 should abort, then
       // abort.
-      CatchType prediction = PredictExceptionCatcher();
-      if (FLAG_abort_on_uncaught_exception &&
-          (prediction == NOT_CAUGHT || prediction == CAUGHT_BY_EXTERNAL) &&
-          (!abort_on_uncaught_exception_callback_ ||
-           abort_on_uncaught_exception_callback_(
-               reinterpret_cast<v8::Isolate*>(this)))) {
-        // Prevent endless recursion.
-        FLAG_abort_on_uncaught_exception = false;
-        // This flag is intended for use by JavaScript developers, so
-        // print a user-friendly stack trace (not an internal one).
-        PrintF(stderr, "%s\n\nFROM\n",
-               MessageHandler::GetLocalizedMessage(this, message_obj).get());
-        PrintCurrentStackTrace(stderr);
-        base::OS::Abort();
+      if (FLAG_abort_on_uncaught_exception) {
+        CatchType prediction = PredictExceptionCatcher();
+        if ((prediction == NOT_CAUGHT || prediction == CAUGHT_BY_EXTERNAL) &&
+            (!abort_on_uncaught_exception_callback_ ||
+             abort_on_uncaught_exception_callback_(
+                 reinterpret_cast<v8::Isolate*>(this)))) {
+          // Prevent endless recursion.
+          FLAG_abort_on_uncaught_exception = false;
+          // This flag is intended for use by JavaScript developers, so
+          // print a user-friendly stack trace (not an internal one).
+          PrintF(stderr, "%s\n\nFROM\n",
+                 MessageHandler::GetLocalizedMessage(this, message_obj).get());
+          PrintCurrentStackTrace(stderr);
+          base::OS::Abort();
+        }
       }
     }
   }
 
   // Set the exception being thrown.
   set_pending_exception(*exception_handle);
   return heap()->exception();
 }
 
 
@@ skipping 2035 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8