[fpc-devel] The "implements" keyword

Christian Iversen chrivers at iversen-net.dk
Sun Aug 6 16:40:06 CEST 2006

On Sunday 06 August 2006 12:12, Florian Klaempfl wrote:
> Christian Iversen wrote:
> > Finally I got some spare time for coding.
> >
> > So, after quite a bit of help from Florian (Thank you!), the
> > implements-keyword is.... well, IMPLEMENTED! Finally!
> >
> > It's not yet in trunk, but it will be soon.
> >
> > As far as I can tell, it's completely hack-free, but I will submit the
> > revisions as patches for code review.
> >
> > The code is still not complete, and there are some needed changes that
> > will happen when I can find the time (for instance, what's the procedure
> > to add new compiler messages? should I just add them to errore.msg?)
> Yes, at the appropriate place. Then run make msg in fpc/compiler and
> commit the changed msg*.inc files as well.

Ok, I'll do that.

> > The current version of the patch adds 2*sizeof(pointer) to each
> > TInterfaceEntry. That might seem like a lot, but with bitpacking this can
> > be brought down to just 1*sizeof(pointer).
> >
> > Now, to make the bitpacking I need to be able to assume VMT's are always
> > aligned to at least 4-byte boundaries. I think this is a safe assumption,
> > but maybe it's not?
> Well, when compiling optimized for size it isn't I fear.

It would really save a lot of space if we could just agree to always align 
VMTs to 4-byte boundaries. Trying to pack them together actually hurts the 
size, in the case of interfaces. 

Christian Iversen

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