Don't crash on stack overflow entering the debugger.

src/debug.cc

-// Copyright 2011 the V8 project authors. All rights reserved.
+// 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
 //       with the distribution.
@@ skipping 748 matching lines @@
     isolate->clear_pending_exception();
     return false;
   }
 
   // Execute the shared function in the debugger context.
   Handle<Context> context = isolate->global_context();
   bool caught_exception;
   Handle<JSFunction> function =
       factory->NewFunctionFromSharedFunctionInfo(function_info, context);
 
-  Execution::TryCall(function, Handle<Object>(context->global()),
-                     0, NULL, &caught_exception);
+  Handle<Object> exception =
+      Execution::TryCall(function, Handle<Object>(context->global()),
+                         0, NULL, &caught_exception);
 
   // Check for caught exceptions.
   if (caught_exception) {
+    ASSERT(!isolate->has_pending_exception());
+    MessageLocation computed_location;
+    isolate->ComputeLocation(&computed_location);
     Handle<Object> message = MessageHandler::MakeMessageObject(
-        "error_loading_debugger", NULL, Vector<Handle<Object> >::empty(),
-        Handle<String>(), Handle<JSArray>());
+        "error_loading_debugger", &computed_location,
+        Vector<Handle<Object> >::empty(), Handle<String>(), Handle<JSArray>());
+    ASSERT(!isolate->has_pending_exception());
+    isolate->set_pending_exception(*exception);
     MessageHandler::ReportMessage(Isolate::Current(), NULL, message);
+    isolate->clear_pending_exception();
     return false;
   }
 
   // Mark this script as native and return successfully.
   Handle<Script> script(Script::cast(function->shared()->script()));
   script->set_type(Smi::FromInt(Script::TYPE_NATIVE));
   return true;
 }
 
 
@@ skipping 2436 matching lines @@
 
 
 EnterDebugger::~EnterDebugger() {
   ASSERT(Isolate::Current() == isolate_);
   Debug* debug = isolate_->debug();
 
   // Restore to the previous break state.
   debug->SetBreak(break_frame_id_, break_id_);
 
   // Check for leaving the debugger.
-  if (prev_ == NULL) {
+  if (!load_failed_ && prev_ == NULL) {
     // Clear mirror cache when leaving the debugger. Skip this if there is a
     // pending exception as clearing the mirror cache calls back into
     // JavaScript. This can happen if the v8::Debug::Call is used in which
     // case the exception should end up in the calling code.
     if (!isolate_->has_pending_exception()) {
       // Try to avoid any pending debug break breaking in the clear mirror
       // cache JavaScript code.
       if (isolate_->stack_guard()->IsDebugBreak()) {
         debug->set_interrupts_pending(DEBUGBREAK);
         isolate_->stack_guard()->Continue(DEBUGBREAK);
@@ skipping 326 matching lines @@
     {
       Locker locker;
       Isolate::Current()->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal