Re: MPS signals and Emacs

[Eli Zaretskii]

> From: Helmut Eller <eller.helmut@gmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  Gerd Möllmann
>  <gerd.moellmann@gmail.com>,
>   emacs-devel@gnu.org
> Date: Mon, 22 Apr 2024 16:10:00 +0200
> 
> I was also puzzled by the fact that during pdump, sigHandle worked fine
> but later during loaddefs-gen not.  I then found this comment in
> init_signals:
> 
>   /* Don't alter signal handlers if dumping.  On some machines,
>      changing signal handlers sets static data that would make signals
>      fail to work right when the dumped Emacs is run.  */
>   if (will_dump_p ())
>     return;
> 
> That explains the puzzling behavior but it makes me wonder what kind of
> machine that could possibly be.  Also MPS clearly has to install memory
> barriers, will_dump_p or not.  Will that affect those machines?

I think we only need to avoid installing signal handlers when dumping
using unexec, because with pdumper we don't dump the data of signal
handlers.  Paul, am I right?

If I'm right, the will_dump_p call should be replaced with
will_dump_with_unexec_p (which is not relevant to the MPS branch
anyway).