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

[Pip Cet]

On Tue, May 26, 2020 at 7:51 AM Paul Eggert <eggert@cs.ucla.edu> wrote:
> On 5/25/20 11:18 PM, Pip Cet wrote:
> > However, this is only because struct Lisp_String happens to have an
> > even number of words. If someone changes that, the old code would
> > break...
>
> No, because struct Lisp_String contains a GCALIGNED_UNION_MEMBER, so it is
> always GC-aligned, and (for older compilers that don't support alignas (8)) 
> this
> is checked statically via 'verify (GCALIGNED (struct Lisp_String))'.

As I said, this was specific to the old code, where LISP_ALIGNMENT,
not GCALIGNMENT, was used by maybe_lisp_pointer. Things should be fine
now (apart from the issue below)!

> Now that I've looked at it, though, I see that I forgot to do something 
> similar
> with struct Lisp_Float, which has the same issue. Fixed by installing the
> attached patch on master.

LGTM.

> > We're still going to have to deal with symbols on --wide-int builds
> > when the two halves of the wide int are saved non-consecutively.
>
> Yes, I think that's the most pressing issue in this area.
> I will have to take a
> break now, though, since I have sleep and other work to do.

Thanks for all the patches and comments!