Add a clang plugin check that flags GC::Cell subclasses (and their
base classes within the Cell hierarchy) that have destructors with
non-trivial bodies. Such logic should use Cell::finalize() instead.
Add GC_ALLOW_CELL_DESTRUCTOR annotation macro for opting out in
exceptional cases (currently only JS::Object).
This prevents us from accidentally adding code in destructors that
runs after something we're pointing to may have been destroyed.
(This could become a problem when the garbage collector sweeps
objects in an unfortunate order.)
This new check uncovered a handful of bugs which are then also fixed
in this commit. :^)
Instead of creating a new single-shot timer every time a setInterval
timer reschedules itself, we now use a repeating Core::Timer internally.
This dramatically reduces timer drift, since the next timeout is now
based on when the timer fired, rather than when the timer callback
completed (which could take arbitrarily long since we run JS).
It's not perfect, but it's a huge improvement and allows us to play
DiabloWeb at full framerate (20 fps).
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
