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.
All non-actors now use PClass exclusively as their type descriptor.
Getting rid of these two classes already removes a lot of obtuse code from the type system, but there's still three more classes to go before a major cleanup can be undertaken.
Removing this variable is needed to remove PClassType and PClassClass as the next step to eliminate all of PClass's subclasses in order to clean up the type system.
- use a memory arena to store flat pointers so that the messed up cleanup can be avoided by deallocating this in bulk.
- added a new SO opcode to the VM to execute a write barrier. This is necessary for all objects that are not linked into one global table, i.e. everything except thinkers and class types.
- always use the cheaper LOS opcode for reading pointers to classes and defaults because these cannot be destroyed during normal operation.
- removed the pointless validation from String.Mid. If the values are read as unsigned the internal validation of FString::Mid will automatically ensure proper results.
- removed some code repetition by inherit all variable types which reference a PField for a variable offset from a base class so that PField replacements can be done with one set of code.
This was a tweak that only makes sense when the scaling factors are low, i.e. 2 vs. 3, but for modern high resolutions it will enlarge things a bit too much.
