From: "Gerd Möllmann" <gerd.moellmann@gmail.com>
To: Pip Cet <pipcet@protonmail.com>
Cc: Andrea Corallo <acorallo@gnu.org>,
Helmut Eller <eller.helmut@gmail.com>,
Eli Zaretskii <eliz@gnu.org>, Paul Eggert <eggert@cs.ucla.edu>,
emacs-devel@gnu.org
Subject: Re: MPS: assertion failed: header_type (h) != IGC_OBJ_FWD
Date: Tue, 23 Jul 2024 05:31:56 +0200 [thread overview]
Message-ID: <m2y15srdg3.fsf@pro2.fritz.box> (raw)
In-Reply-To: <-QjTMdYbNwCUDNk0Q5XFZR2kQ0_8DHRu3A-n1Rr1_mUBhg4inwpUb3jL0lp2J1VvJcUkIQRB5v1Zy4oNePJ7V9ixJ3l91CCrb3awC_146VM=@protonmail.com> (Pip Cet's message of "Tue, 23 Jul 2024 00:36:09 +0000")
Pip Cet <pipcet@protonmail.com> writes:
> On Friday, July 19th, 2024 at 04:38, Gerd Möllmann <gerd.moellmann@gmail.com> wrote:
>> Gerd Möllmann gerd.moellmann@gmail.com writes:
>>
>> > Andrea Corallo acorallo@gnu.org writes:
>> >
>> > > > Let's see how long igc survives this time :-).
>> > >
>> > > Hi Gerd,
>> > >
>> > > if you want to use '__builtin_unwind_init' be aware that this GCC bug
>> > > I've found sometime ago [1] might make the builtin ineffective. It
>> > > might not effect your generated code but in case you need you can see
>> > > how we work it around in 'flush_stack_call_func'.
>> > >
>> > > Regards
>> >
>> > Thanks, that could become important at some point on platforms other
>> > than macOS. AFAIK, one cannot build Emacs with GCC on newer versions of
>> > macOS because the SDK is incompatible with GCC, so GCC is out of the
>> > picture.
>> >
>> > I haven't heard yet of anyone else having problems of the sort I have
>> > here on macOS on other platforms. But maybe that comes up later.
>>
>>
>> It didn't help, and no more ideas at the moment :-(.
>
> Can you try compiling with -fno-omit-frame-pointer? I just spent
> entirely too much time tracing down a bug in my build to a missing
> option (of the same name) to x86_64 gcc. The frame pointer is stored
> in a mangled format by setjmp() on both darwin and glibc systems, and
> that caused weird problems (and since gcc generates different code
> with and without "-g", I had to do that without proper debugger
> support...)
Thanks for letting me know! That indeed sounds like a candidate.
I wonder what __builtin_unwind_init does with the frame pointer. Using
it (in MPS itself) definitely has some effect on my system, although it
apparently is not a complete fix. But maybe there's more than one bug.
Hmm.
> Anyway, I think both architectures "allow" using the frame pointer
> register, so we're probably going to have to enforce that option,
> which will limit us to clang and gcc compilers unless someone figures
> out the configure magic...
The macOS arm ABI says
The ARM standard delegates certain decisions to platform designers.
Apple platforms adhere to the following choices:
The platforms reserve register x18. Don’t use this register.
The frame pointer register (x29) must always address a valid frame
record. Some functions — such as leaf functions or tail calls — may opt
not to create an entry in this list. As a result, stack traces are
always meaningful, even without debug information.
I'll try the -fno-omit-frame-pointer anyway. Maybe I'm misinterpreting
that paragraph.
next prev parent reply other threads:[~2024-07-23 3:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-14 4:12 MPS: assertion failed: header_type (h) != IGC_OBJ_FWD Gerd Möllmann
2024-07-14 5:30 ` Pip Cet
2024-07-14 7:00 ` Gerd Möllmann
2024-07-14 7:08 ` Gerd Möllmann
2024-07-16 13:02 ` Gerd Möllmann
2024-07-16 13:38 ` Eli Zaretskii
2024-07-16 13:47 ` Gerd Möllmann
2024-07-16 14:11 ` Eli Zaretskii
2024-07-16 14:39 ` Gerd Möllmann
2024-07-16 15:21 ` Eli Zaretskii
2024-07-16 16:54 ` Gerd Möllmann
2024-07-16 14:19 ` Helmut Eller
2024-07-16 14:48 ` Gerd Möllmann
2024-07-16 15:22 ` Eli Zaretskii
2024-07-16 16:13 ` Pip Cet
2024-07-16 16:47 ` Gerd Möllmann
2024-07-17 7:51 ` Andrea Corallo
2024-07-17 19:47 ` Gerd Möllmann
2024-07-18 15:08 ` Gerd Möllmann
2024-07-18 16:05 ` Pip Cet
2024-07-18 16:33 ` Gerd Möllmann
2024-07-18 19:06 ` Andrea Corallo
2024-07-18 19:33 ` Gerd Möllmann
2024-07-19 4:38 ` Gerd Möllmann
2024-07-23 0:36 ` Pip Cet
2024-07-23 3:31 ` Gerd Möllmann [this message]
2024-07-16 15:49 ` Paul Eggert
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