Re: MPS signals and Emacs

[Gerd Möllmann]

Paul Eggert <eggert@cs.ucla.edu> writes:

> On 2024-04-21 23:15, Eli Zaretskii wrote:
>
>> Paul, can you please help by suggesting how to handle this situation?
>
> I don't know MPS or the MPS branch. However, it sounds like the MPS
> branch should indeed call init_signals (to let Emacs set up signal
> handlers the way it likes) before calling ProtSetup (to let MPS
> override Emacs's handling of SIGBUS and SIGSEGV).
>
> Emacs's SIGBUS and SIGSEGV handlers are used only deal with serious
> internal fatal errors, which should never happen, and if they do
> happen I hope MPS will do the right thing with them by passing them to
> Emacs's thread_fatal_action. You should test that by injecting a
> serious internal fatal error (usage of a bad pointer) into Emacs and
> seeing that MPS does the right thing with it.

Thanks!

> I assume that MPS is not being used to allocate any of Emacs's own
> objects, as copying collectors are incompatible with Emacs's habit of
> squirreling away pointers inside integers.

It's excactly that, a (mostly) copying collector for Emacs :-). Also
other stuff, like concurrent, incremental, generational, thread-safe.

The branch is young (8 weeks), but it's looking good so far, I think.