http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58585
--- Comment #4 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
This is the code I am playing with:
/* Walk bases. */
for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
/* Walking bases that have no virtual method is pointless excercise. */
if (polymorphic_type_binfo_p (base_binfo))
record_binfo (nodes, base_binfo, otr_type,
/* In the case of single inheritance, the virtual table
is shared with the outer type. */
BINFO_OFFSET_ZEROP (base_binfo)
? type_binfo : base_binfo,
otr_token, inserted,
matched_vtables, anonymous);
(i.e. using BINFO_OFFSET_ZEROP check instead of BINFO_VTABLE != NULL).
I think I understand the problem now. The binfos of C looks like
BINFO of C, BINFO vtable is C's vtable
BASE:
BINFO of B, BINFO vtable is non-NULL, offset is 8
BASE:
BINFO of A, BINFO vtable is non-NULL, offset is 0.
i.e. by the virtual inheritance the A is outside layout of B. So while B's
VTABLE is set, A's VTABLE should be VTABLE of C, my code however considers
VTABLE of B.
get_binfo_at_offset won't get confused, since type of C contains both A and B
as fields, so it gets to BINFO of A directly without walking BINFO of B.
Is there way how to keep track of the vtables w/o doing the walk based on
fields instead of BINFO_BASEs? If not, I will simply switch record_binfos to it
- it seems quite straighforward, but it will end up with more walking, since
there are more fileds than bases.
