systemc: Fix the implementation of sc_event::triggered.

This function just returned false. The new implementation uses the
scheduler's changeStamp function to keep track of how recently the
event was triggered so it can return return the right value.

Change-Id: Idf61cd459e53e224a33d3e53c16210f5e0a99a3a
Reviewed-on: https://gem5-review.googlesource.com/c/12825
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/event.cc

@@ -47,7 +47,7 @@ Event::Event(sc_core::sc_event *_sc_event) : Event(_sc_event, nullptr) {}
 
 Event::Event(sc_core::sc_event *_sc_event, const char *_basename_cstr) :
     _sc_event(_sc_event), _basename(_basename_cstr ? _basename_cstr : ""),
-    delayedNotify([this]() { this->notify(); })
+    delayedNotify([this]() { this->notify(); }), _triggeredStamp(~0ULL)
 {
     Module *p = currentModule();
 
@@ -166,6 +166,8 @@ Event::notify()
     if (delayedNotify.scheduled())
         scheduler.deschedule(&delayedNotify);
 
+    _triggeredStamp = scheduler.changeStamp();
+
     notify(staticSenseMethod);
     notify(dynamicSenseMethod);
     notify(staticSenseThread);
@@ -194,7 +196,7 @@ Event::cancel()
 bool
 Event::triggered() const
 {
-    return false;
+    return _triggeredStamp == scheduler.changeStamp();
 }
 
 Events topLevelEvents;

src/systemc/core/event.hh

@@ -85,6 +85,7 @@ class Event
     void cancel();
 
     bool triggered() const;
+    uint64_t triggeredStamp() const { return _triggeredStamp; }
 
     static Event *
     getFromScEvent(sc_core::sc_event *e)
@@ -147,6 +148,7 @@ class Event
     sc_core::sc_object *parent;
 
     ScEvent delayedNotify;
+    mutable uint64_t _triggeredStamp;
 
     mutable StaticSensitivities staticSenseMethod;
     mutable StaticSensitivities staticSenseThread;