Like the symbols and the VM functions this is data that is static from startup until shutdown and has no need to be subjected to garbage collection. All things combined this reduces the amount of GC-sensitive objects at startup from 9600 to 600.
Making this an object had little to no advantage, except being able to remove the deleter code. Now, with some of the class data already being allocated in a memory arena so that freeing it is easier, this can also be used for the drop item lists which makes it unnecessary to subject them to the GC. This also merges the memory arenas for VM functions and flat pointers because both get deleted at the same time so they can share the same one.
Now all actors have the same metaclass and therefore it will always be the same size which will finally allow some needed changes to the type system which couldn't be done because it was occasionally necessary to replace tentatively created classes due to size mismatches.
There's simply never enough of them and they are used far too infrequently to justify the hassle of tagging along two TMaps per class.
For what they provide, single global lists that handle all player classes at once are fully sufficient.
The goal is to get rid of PClassPlayerPawn and PClassInventory so that the old assumption that all actor class descriptors have the same size can be restored
This is important to remove some code that seriously blocks optimization of the type table because that can only be done if types do not need to be replaced.
Symbols are very easy to manage once they are in a symbol table and there's lots of them so this reduces the amount of work the GC needs to do quite considerably.
After cleaning out compile-time-only symbols there will still be more than 2000 left, one for each function and one for each member variable of a class or struct.
This means more than 2000 object that won't need to tracked constantly by the garbage collector.
Note that loose fields which do occur during code generation will be GC'd just as before.
- removed all pointer declarations to types from the symbols. All types must be placed into the type table which means that they can be considered static.
As it stood, just compiling the internal ZScript code created more than 9000 DObjects, none of which really need to be subjected to garbage collection, aside from allowing lazy deallocation.
This puts an incredible drag on the garbage collector which often needs several minutes to finish processing before actual deletion can start.
The VM functions with roughly 1800 of these objects were by far the easiest to refactor so they are now. They also use a memory arena now which significantly reduces their memory footprint.
Rachael Alexanderson
Christoph Oelckers
alexey.lysiuk
Magnus Norddahl
nashmuhandes
Major Cooke