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Re: Pascal front-end integration
> I also don't recommend trying to keep compatibility before 4.0; working
> with 4.0 would suffice to keep the new GPC developments usable with a GCC
> release and the differences between 4.0 and earlier compilers are
> sufficiently large that the saving from not trying to be compatible with
> earlier versions would be substantial. In general, compatibility with the
> most recent release series should suffice; if the 4.0 series is
> insufficiently stable, effort would better be devoted to improving it than
> to keeping compatibility with older and less-maintained series.
I'm not only talking of genuine backend bugs (though, of course,
there may be some that are not exercised by other backends, as there
have been in various 3.x versions), but also of frontend bugs that
are not exercised with older backends. And of course, the new code
to adapt gpc to 4.x needs to be tested and fixed as well.
So to make it short, for my own productive work I'm not going to use
gpc with a backend that hasn't been tested with gpc for at least
several months. Therefore, I'm not going to do my own frontend work
on such a version, as I want to be able to try it immediately. So if
you think dropping older backends is the only way to support 4.x, a
fork would be inevitable. But I'm not convinced this is really
necessary.
Waldek Hebisch wrote:
> James A. Morrison wrote:
> > I beleive function-at-a-time goes back to gcc 3.0. Creating function trees
> > then passes off to an expand function within the pascal front-end would
> > probably work with most gcc backends. The cgraph stuff is a bit more of
> > an issue. I think cgraph appeared in gcc 3.4.
> >
>
> AFAIK 4.0 is the first back-end which can handle the whole function
> as a tree. All earlier versions had a tree walker in the front-end
> which did tree to RTL conversion. Since such tree walker is not
> needed in 4.0 I think that GPC should not support function-at-a-time
> for 3.x.
Agreed, this would just be unnecessary extra work.
So IMHO the best thing for a smooth transition would be to add 4.x
support as far as we can, with conditionals, so everyone can test it
and we can drop earlier backend as soon as (safely) possible.
Frank
--
Frank Heckenbach, frank@g-n-u.de
http://fjf.gnu.de/
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