Jon Coppeard
f24562cc04
This involved a bit more work. Getting the exact number of object slots can be quite involved but we don't need this for conucrrent marking. I added functions to get slot count accurate up to SMALL_SLOTSPAN_MAX for use when calculating the number of used fixed slots, as we don't need accuracy beyond MAX_FIXED_SLOTS (16) for this anyway. Differential Revision: https://phabricator.services.mozilla.com/D307519