Re: Merging MPS a.k.a. scratch/igc, yet again

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: "Pip Cet via \"Emacs development discussions.\"" <emacs-devel@gnu.org>,
>  Helmut Eller <eller.helmut@gmail.com>
> Date: Thu, 19 Dec 2024 20:57:45 +0100
> 
> Pip Cet <pipcet@protonmail.com> writes:
> 
> > Gerd Möllmann <gerd.moellmann@gmail.com> writes:
> >
> >> Pip Cet via "Emacs development discussions." <emacs-devel@gnu.org>
> >> writes:
> >>
> >>> Does anyone remember what our conclusion was wrt
> >>> -fno-omit-frame-pointer?  I seem to remember there was a patch to MPS to
> >>> avoid relying on setjmp() to save all registers, but I'd still be
> >>> happier if we enabled that for all MPS builds, since we don't know
> >>> whether our MPS has the patch.
> >>
> >> I'm using -fno-omit-frame-pointer, but I don't remember why. I think
> >> Helmut said something or so (in CC).
> >
> > We tried not using it, it caused a bug, I spent too many hours tracking
> > that one down, so now I think we should make configure.ac always enable
> > it, even though it should be a no-op on some architectures (I think
> > macOS on aarch64 is one of them).
> 
> I agree.
> 
> And maybe we should tell testers of the branch to stick to the compiler
> options Emacs uses by default for now? To reduce the number of moving
> parts, at least for a while. Don't what guarantees Emacs currently gives
> of working with what compiler options.

I think sticking to the default options is indeed a good idea.

> > I'm not sure what the right thing to do here is, though: do we want
> > force CFLAGS to include -fno-omit-frame-pointer, or set it only when
> > CFLAGS isn't specified explicitly, or is looking at user-provided CFLAGS
> > and complaining about them the right thing to do?
> 
> I'd force it, but I'm reckless :-).

Agreed.