bug#43725: 28.0.50; Include feature/native-comp into master

[Andrea Corallo]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Eli Zaretskii <eliz@gnu.org> writes:
>
>>> Mmmh, I think technically we could, similarly to what we do for the
>>> advice, synthesize compile and install a trampoline.  This would read
>>> the symbol-function and calls what's in inside.
>>> 
>>> This trampoline installation would be triggered inside Ffset.
>>> 
>>> So yeah I think we could, if that's the preferred way I can try this
>>> way.
>>
>> Lars, Stefan: do you agree that this is the preferred way?
>
> I'm not really qualified to have an opinion here, but if this allows
> redefining primitives, I'm all for it.  Redefining primitives is a
> useful tool.
>
> Would these trampolines be installed only if the primitives are
> redefined, so there'd be no performance impact on code running normally?

That's correct.

I did some experimentation today and also the implementation was easy as
the trampoline to be synthesized is exactly the same to what we
synthesize already for advising, essentially I just had to add the
proper trigger in fset.

At this point I'm also for going this way as it just reduce the
incompatibly surface and I don't see considerable downsides.

  Andrea