bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects

[Paul Eggert]

On 5/30/20 2:49 PM, Pip Cet wrote:
> On Sat, May 30, 2020 at 9:27 PM Paul Eggert <eggert@cs.ucla.edu> wrote:
> > > Is it misaligned pointers into floats you're worried about?
> >
> > Yes, and it's plausible there will be pointers misaligned because
> > Lisp_Float has been added to them.
>
> Sorry for being dense, but I still don't understand. This is on
> !LSB_TAG machines, where Lisp_Float does not affect the representation
> of the lower 32 bits. On LSB_TAG machines, the other code path is
> taken.

Oh, I see I am being the dense one. I was thinking based on some of my 
master-branch improvements. One option is to do away with 
mark_maybe_object entirely, so that one needn't deal with looking at 
each part of the stack twice (this is for efficiency).

In emacs-27 the patch you proposed earlier is probably OK, though I 
haven't had time to think through all the possibilities.