systemc: Add an error check to the deprecated notify_delayed.

This can't override pending notifications like normal notify does.

Change-Id: Ie5f12a97ffdcc3dfca20fa7852f89687ee8bfca3
Reviewed-on: https://gem5-review.googlesource.com/c/13305
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/event.cc

@@ -178,6 +178,16 @@ Event::notify(const sc_core::sc_time &t)
     scheduler.schedule(&delayedNotify, t);
 }
 
+void
+Event::notifyDelayed(const sc_core::sc_time &t)
+{
+    if (delayedNotify.scheduled()) {
+        SC_REPORT_ERROR("(E531) notify_delayed() cannot be called on events "
+                "that have pending notifications", "");
+    }
+    notify(t);
+}
+
 void
 Event::cancel()
 {

src/systemc/core/event.hh

@@ -82,6 +82,7 @@ class Event
     {
         notify(sc_core::sc_time(d, u));
     }
+    void notifyDelayed(const sc_core::sc_time &t);
     void cancel();
 
     bool triggered() const;

src/systemc/core/sc_event.cc

@@ -342,8 +342,16 @@ void sc_event::notify(const sc_time &t) { _gem5_event->notify(t); }
 void sc_event::notify(double d, sc_time_unit u) { _gem5_event->notify(d, u); }
 void sc_event::cancel() { _gem5_event->cancel(); }
 bool sc_event::triggered() const { return _gem5_event->triggered(); }
-void sc_event::notify_delayed() { _gem5_event->notify(SC_ZERO_TIME); }
-void sc_event::notify_delayed(const sc_time &t) { _gem5_event->notify(t); }
+void
+sc_event::notify_delayed()
+{
+    _gem5_event->notifyDelayed(SC_ZERO_TIME);
+}
+void
+sc_event::notify_delayed(const sc_time &t)
+{
+    _gem5_event->notifyDelayed(t);
+}
 
 sc_event_and_expr
 sc_event::operator & (const sc_event &e) const