patch to bring java vtables closer to g++ abi conformance

Thu Jan 24 22:24:00 GMT 2002

On Wed, Jan 23, 2002 at 05:35:40PM -0800, Per Bothner wrote:
> Bryce McKinlay wrote:
>> >Given:
> >
> >class A {}
> >class B extends A {}
> >
> >Then B would have a vtable which looks something like:
>> How about:
>> [-6] &Object.class
> [-5] &A.class
> [-4] &B.class
> [-3] -2 /* depth, negated */
> [-2] offset_to_top (always 0)
> [-1] type_info
> <-- vtable pointer points here
> [0] GC descriptor<-- vtable pointer points here
> [1] &java.lang.Object.hashCode()
> [2] ...etc
> >
> >"b instanceof A" then becomes something like

As far as this goes, do whatever you want - but put the symbol name for
the vtable where it would be if this were a C++ class. Generally, two
words before the vtable pointer points. Being careful of
integer/pointer sizes on various architectures, of course.
After that, I don't care :)
-- 
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer