https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86763
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |NEW
CC| |jason at gcc dot gnu.org,
| |nathan at gcc dot gnu.org,
| |rguenth at gcc dot gnu.org
Component|middle-end |c++
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
So the question is why T doesn't get TYPE_TYPELESS_STORAGE set even though
we propagate that flag from children upwards in place_field. That's what
is missing here and why things go wrong.
Ah, so we go
build_base_field (rli=0x2ea1780, binfo=0x7ffff6a2f120, offsets=0x2ea2280,
next_field=0x7ffff6a285c8)
at /space/rguenther/src/svn/gcc-8-branch/gcc/cp/class.c:4244
4244 tree t = rli->t;
(gdb) p basetype->type_common.typeless_storage
$30 = 1
OK
4262 decl = build_base_field_1 (t, basetype, next_field);
(gdb) p decl->typed.type->type_common.typeless_storage
$31 = 0
looks like the as-base type doesn't inherit this flag. If I fix that up here
where it matters rather than tracking down the gazillion places the C++ FE
seems to set CLASSTYPE_AS_BASE and where I'm unsure at that time layout
is finished the bug is fixed:
Index: gcc/cp/class.c
===================================================================
--- gcc/cp/class.c (revision 263209)
+++ gcc/cp/class.c (working copy)
@@ -4202,6 +4202,8 @@ build_base_field_1 (tree t, tree basetyp
{
/* Create the FIELD_DECL. */
gcc_assert (CLASSTYPE_AS_BASE (basetype));
+ TYPE_TYPELESS_STORAGE (CLASSTYPE_AS_BASE (basetype))
+ = TYPE_TYPELESS_STORAGE (basetype);
tree decl = build_decl (input_location,
FIELD_DECL, NULL_TREE, CLASSTYPE_AS_BASE (basetype));
DECL_ARTIFICIAL (decl) = 1;
C++ folks?
