bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree

[Andrea Corallo]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Andrea Corallo <akrl@sdf.org>
>> Cc: 46256@debbugs.gnu.org
>> Date: Fri, 05 Mar 2021 13:56:24 +0000
>> 
>> > Why can't we have a rule in the Makefile conditioned by
>> > HAVE_NATIVE_COMP?
>> 
>> We certainly can, the difficult part is to generate the rule as the .eln
>> filename is known only by the Emacs binary.  I'm probably missing
>> something.
>
> Oh, you mean because of the ABI hash?  Yes, that'd preclude using Make
> to decide when a .eln file needs to be regenerated.

Yep

>> > Each time we add another Emacs invocation in the build process, we
>> > make the goal of supporting cross-build farther.
>> 
>> Point taken.
>> 
>> [ To be considered also that as of today libgccjit is not meant to work
>> for cross compilation. ]
>
> Then perhaps we could invoke Emacs only in order to detect when the
> ABI has changed.  Because when that happens, we need to regenerate all
> the preloaded *.eln files anyway, so there's no need to test
> individual files.  Right?

Sounds good to me.

  Andrea