protected override void DoExecute()
{
Report.Debug (DebugFlags.SSE, "{0} rti execute", sse);
if (helper != null)
throw new InternalError ("{0} rti already has a helper operation", sse);
helper = new OperationRuntimeInvokeHelper (sse, this);
Result.ID = helper.ID;
sse.rti_stack.Push (this);
sse.PushOperation (helper);
}