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

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

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'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 :-).