We currently size the storage inside JSAutoEnterCompartment based on a platform-specific guess. This broke ted's iOS port, and it's ugly.
We may be able to rely on the fact (?) that 32-bit systems with alignof(uint64) == 4 have 13-word AutoCompartments, while 32-bit systems with alignof(uint64) == 8 have 16-word AutoCompartments.
Created attachment 565995 [details] [diff] [review]
Comment on attachment 565995 [details] [diff] [review]
I think this works.
*** Bug 693585 has been marked as a duplicate of this bug. ***
Just for interest in case this dings other arches, on PPC this turned out to be 15 bytes, for some reason.