Unfortunately this turned out harder than expected because of FSharedStringArena making some strong assumptions about the underlying implementation.
(cherry picked from commit 2f6dc46f14)
This is only the parsing part, the arrays are not yet getting evaluated.
This required quite a hacky workaround because the gramma couldn't be made to accept the rule. The scanner will check if a 'static' token is immediately followed by a 'const' token and will combine both to a new 'staticconst' token that does not create conflicts with other rules.
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.
- Since the number of small allocations here is extremely high this will help a lot to prevent fragmentation and since most nodes are collected up front and this is done when no large resources are being loaded it won't cause heap spikes.
let Emit methods delete FxExpression arrays when they are done.
- For some reason the deletion process does not work 100%, there are always some nodes left behind and so far I haven't found them. This ensures that these arrays do not live any longer than needed.
