systemc: Fix a couple memory errors.

Because events are held in vectors, it doesn't make sense to keep an
iterator into the parent to keep track of where that event is for easy
removal since the iterator becomes invalid when the vector is changed.

The events need to be stored in a vector because systemc defines an
accessor which returns that vector, and building a vector on the fly
would be cumbersome.

Also, make sure the Event parent pointer is set to nullptr if there
isn't a parent.

Change-Id: I63a676190e7747e60baaca50009161d47bfc1c54
Reviewed-on: https://gem5-review.googlesource.com/12039
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

4 files changed, 16 insertions, 7 deletions

diff --git a/src/systemc/core/event.cc b/src/systemc/core/event.cc
index 1623cf9e8..05670fe59 100644
--- a/src/systemc/core/event.cc
+++ b/src/systemc/core/event.cc
@@ -29,6 +29,7 @@
 
 #include "systemc/core/event.hh"
 
+#include <algorithm>
 #include <cstring>
 #include <utility>
 
@@ -51,12 +52,14 @@ Event::Event(sc_core::sc_event *_sc_event, const char *_basename) :
         parent = p->obj()->sc_obj();
     else if (scheduler.current())
         parent = scheduler.current();
+    else
+        parent = nullptr;
 
     if (parent) {
         Object *obj = Object::getFromScObject(parent);
-        parentIt = obj->addChildEvent(_sc_event);
+        obj->addChildEvent(_sc_event);
     } else {
-        parentIt = topLevelEvents.emplace(topLevelEvents.end(), _sc_event);
+        topLevelEvents.emplace(topLevelEvents.end(), _sc_event);
     }
 
     if (parent)
@@ -74,9 +77,12 @@ Event::~Event()
 {
     if (parent) {
         Object *obj = Object::getFromScObject(parent);
-        obj->delChildEvent(parentIt);
+        obj->delChildEvent(_sc_event);
     } else {
-        std::swap(*parentIt, topLevelEvents.back());
+        EventsIt it = find(topLevelEvents.begin(), topLevelEvents.end(),
+                           _sc_event);
+        assert(it != topLevelEvents.end());
+        std::swap(*it, topLevelEvents.back());
         topLevelEvents.pop_back();
     }
 
diff --git a/src/systemc/core/event.hh b/src/systemc/core/event.hh
index 6d2f46d42..f9d3b2040 100644
--- a/src/systemc/core/event.hh
+++ b/src/systemc/core/event.hh
@@ -103,7 +103,6 @@ class Event
     bool _inHierarchy;
 
     sc_core::sc_object *parent;
-    EventsIt parentIt;
 
     void delayedNotify();
     EventWrapper<Event, &Event::delayedNotify> delayedNotifyEvent;
diff --git a/src/systemc/core/object.cc b/src/systemc/core/object.cc
index 39403ca34..13476619b 100644
--- a/src/systemc/core/object.cc
+++ b/src/systemc/core/object.cc
@@ -29,6 +29,8 @@
 
 #include "systemc/core/object.hh"
 
+#include <algorithm>
+
 #include "base/logging.hh"
 #include "systemc/core/module.hh"
 #include "systemc/core/scheduler.hh"
@@ -230,8 +232,10 @@ Object::addChildEvent(sc_core::sc_event *e)
 }
 
 void
-Object::delChildEvent(EventsIt it)
+Object::delChildEvent(sc_core::sc_event *e)
 {
+    EventsIt it = std::find(events.begin(), events.end(), e);
+    assert(it != events.end());
     std::swap(*it, events.back());
     events.pop_back();
 }
diff --git a/src/systemc/core/object.hh b/src/systemc/core/object.hh
index c87a98b2d..cb759d890 100644
--- a/src/systemc/core/object.hh
+++ b/src/systemc/core/object.hh
@@ -88,7 +88,7 @@ class Object
     sc_core::sc_object *sc_obj() { return _sc_obj; }
 
     EventsIt addChildEvent(sc_core::sc_event *e);
-    void delChildEvent(EventsIt it);
+    void delChildEvent(sc_core::sc_event *e);
 
   private:
     sc_core::sc_object *_sc_obj;