Re: [External] : Re: Question about native compilation (bug?)

[Andrea Corallo]

Drew Adams <drew.adams@oracle.com> writes:

>> >> Redefining a primitive (thing that is not recommended but often done)
>> >> one must at least use the same signature as the original one.  I don't
>> >> think we support the case where the new definition is of a different
>> >> signature.  Native compilation might be just more sensitive in this
>> >> unsupported condition.
>> >
>> > I don't know whether the same problem arises if
>> > the redefined function has a Lisp instead of a
>> > C definition.  If not, then what you say might
>> > have a bit more sway.
>> 
>> Should be only about primitives (C definitions).
>
> OK, thx.
>
> What about my other questions, e.g. wrt fixing this?

I haven't done any recent analysis, from what I remember it is not
easily fixable.

That said I think is not worth of, redefining primitives is already
discouraged by the manual and dangerous (more on that later), doing it
with a different signature it's just kamikaze behavior.

Note also that redefining primitives in Emacs is not only disincouraged,
but is really not guaranteed to work properly.  The redefinition will
not take effect executing bytecode if the primitive has a dedicated
byteopcode and it will *not* take effect either for any call to the
primiteve done form C itself.

  Andrea