Re: --with-native-compilation build failure on 32-bit systems

[Andrea Corallo]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Andrea Corallo <akrl@sdf.org>
>> Cc: larsi@gnus.org, jrm@ftfl.ca, emacs-devel@gnu.org, emacs@FreeBSD.org
>> Date: Wed, 17 Aug 2022 19:59:59 +0000
>> 
>> Okay, I had some time to work on this and this is what's going:
>> 
>> After having loaded ediff-hooks temacs never sweeps vectors because,
>> even if call `garbage-collect' before dumping, this is inhibited cause
>> we overflowed purespace.
>> 
>> Interestingly we warn for purespace overflow calling 'check_pure_size'
>> when dumping with unexec and not with pdumper.  Given this makes the GC
>> not functional (at least in this phase) I'm wondering if we shouldn't do
>> this as well.
>
> I always thought that pure-space overflow with pdumper doesn't matter,
> that's why we don't warn.  You seem to be saying that it does matter?

It certanly does, at least in temacs if using using purecopy we overflow
the purespace.

> By "makes GC not functional" do you mean during dumping, or do you
> mean after restarting Emacs with the pdumper file?

The first, during dumping, I believe the produced emacs is functional.

>> Also, thinking about the whole system even better, I think fixing-up CUs
>> reachable from named functions is definitely a bad for another reason
>> that is lambdas!  We could have a lambda referenced somewhere that keeps
>> a CU loaded and we need to fix it up anyway before dumping.
>> 
>> So yeah I guess tomorrow I'll prepare the patch were we keep a list of
>> loaded CU to fix-up.
>
> Thanks, but why does this only affect 32-bit builds?

That's a good question, I guess for some reason we overflowed only on
the 32-bit builds?

Thanks

  Andrea