S/390: Enable vcall thunks

[Mark Mitchell]

--On Monday, October 21, 2002 09:10:39 PM +0200 Ulrich Weigand 
<Ulrich.Weigand@de.ibm.com> wrote:

>
> Mark Mitchell wrote:
>
>> Cool!  I'm glad to see target maintainers implementing this hook; one
>> more corner case failure will disappear...
>
> I hope I got the semantics right; I must confess I didn't really
> understand why this is needed ;-)

Me neither, and I've been working on this stuff for years. :-)

> What would be really nice is more testcases; the one case you
> provided only tests the case delta == 0 and vcall_offset == some
> small negative value.  On i386 there's probably not much difference,
> but on platforms where you need to generate more complex code to
> load large literals (like s390), having test cases for different
> ranges of those constants would be helpful (e.g. a case with
> delta and/or vcall_offset > 4K or > 32K).

You could arrange the first by making the various classes very big;
that will increase delta.  Making the vcall offset very large requires
having lots and lots of virtual functions...  Perhaps I will put
together a test like that some day. :-)

-- 
Mark Mitchell                mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com