- added GC support to the events. OF_Fixed is not recommended because it can seriously impede the GC's functionality if just being used as a lazy means to avoid collection.

src/dobjgc.cpp

@@ -78,6 +78,7 @@
 #include "menu/menu.h"
 #include "intermission/intermission.h"
 #include "g_levellocals.h"
+#include "events.h"
 
 // MACROS ------------------------------------------------------------------
 
@@ -331,6 +332,8 @@ static void MarkRoot()
 	DThinker::MarkRoots();
 	FCanvasTextureInfo::Mark();
 	Mark(DACSThinker::ActiveThinker);
+	Mark(E_FirstEventHandler);
+	Mark(E_LastEventHandler);
 	for (auto &s : level.sectorPortals)
 	{
 		Mark(s.mSkybox);

src/events.cpp

@@ -37,32 +37,42 @@ bool E_RegisterHandler(DStaticEventHandler* handler)
 	// 2. MyHandler3->2:
 	//    E_FirstEventHandler = MyHandler2, E_LastEventHandler = MyHandler3
 
+	// (Yes, all those write barriers here are really needed!)
 	if (before != nullptr)
 	{
 		// if before is not null, link it before the existing handler.
 		// note that before can be first handler, check for this.
 		handler->next = before;
+		GC::WriteBarrier(handler, before);
 		handler->prev = before->prev;
+		GC::WriteBarrier(handler, before->prev);
 		before->prev = handler;
+		GC::WriteBarrier(before, handler);
 		if (before == E_FirstEventHandler)
+		{
 			E_FirstEventHandler = handler;
+			GC::WriteBarrier(handler);
+		}
 	}
 	else
 	{
 		// so if before is null, it means add last.
 		// it can also mean that we have no handlers at all yet.
 		handler->prev = E_LastEventHandler;
+		GC::WriteBarrier(handler, E_LastEventHandler);
 		handler->next = nullptr;
-		if (E_FirstEventHandler == nullptr)
-			E_FirstEventHandler = handler;
+		if (E_FirstEventHandler == nullptr)	E_FirstEventHandler = handler;
 		E_LastEventHandler = handler;
+		GC::WriteBarrier(handler);
 		if (handler->prev != nullptr)
+		{
 			handler->prev->next = handler;
+			GC::WriteBarrier(handler->prev, handler);
+		}
 	}
 
 	if (handler->IsStatic())
 	{
-		handler->ObjectFlags |= OF_Fixed;
 		handler->ObjectFlags |= OF_Transient;
 	}
 
@@ -80,16 +90,28 @@ bool E_UnregisterHandler(DStaticEventHandler* handler)
 
 	// link out of normal list
 	if (handler->prev)
+	{
 		handler->prev->next = handler->next;
+		GC::WriteBarrier(handler->prev, handler->next);
+	}
 	if (handler->next)
+	{
 		handler->next->prev = handler->prev;
+		GC::WriteBarrier(handler->next, handler->prev);
+	}
 	if (handler == E_FirstEventHandler)
+	{
 		E_FirstEventHandler = handler->next;
+		GC::WriteBarrier(handler->next);
+	}
 	if (handler == E_LastEventHandler)
+	{
 		E_LastEventHandler = handler->prev;
+		GC::WriteBarrier(handler->prev);
+	}
 	if (handler->IsStatic())
 	{
-		handler->ObjectFlags &= ~(OF_Fixed|OF_Transient);
+		handler->ObjectFlags &= ~OF_Transient;
 		handler->Destroy();
 	}
 	return true;

src/events.h

@@ -77,6 +77,7 @@ void E_SerializeEvents(FSerializer& arc);
 class DStaticEventHandler : public DObject // make it a part of normal GC process
 {
 	DECLARE_CLASS(DStaticEventHandler, DObject)
+	HAS_OBJECT_POINTERS
 public:
 	DStaticEventHandler()
 	{
@@ -99,6 +100,7 @@ public:
 	void Serialize(FSerializer& arc) override
 	{
 		Super::Serialize(arc);
+		/*
 		if (arc.isReading())
 		{
 			Printf("DStaticEventHandler::Serialize: reading object %s\n", GetClass()->TypeName.GetChars());
@@ -107,6 +109,7 @@ public:
 		{
 			Printf("DStaticEventHandler::Serialize: store object %s\n", GetClass()->TypeName.GetChars());
 		}
+		*/
 
 		arc("Order", Order);
 		arc("IsUiProcessor", IsUiProcessor);