[PATCH] [11/12/13/14 Regression] ABI break in _Hash_node_value_base since GCC 11 [PR 111050]

[Sam James]

François Dumont via Gcc-patches <gcc-patches@gcc.gnu.org> writes:

> Following confirmation of the fix by TC here is the patch where I'm
> simply adding a 'constexpr' on _M_next().
>
> Please let me know this ChangeLog entry is correct. I would prefer
> this patch to be assigned to 'TC' with me as co-author but I don't
> know how to do such a thing. Unless I need to change my user git
> identity to do so ?

git commit --author="TC <email.here>" --amend

>
>     libstdc++: Add constexpr qualification to _Hash_node::_M_next()
>
> https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=1b6f0476837205932613ddb2b3429a55c26c409d
>     changed _Hash_node_value_base to no longer derive from
> _Hash_node_base, which means
>     that its member functions expect _M_storage to be at a different
> offset. So explosions
>     result if an out-of-line definition is emitted for any of the
> member functions (say,
>     in a non-optimized build) and the resulting object file is then
> linked with code built
>     using older version of GCC/libstdc++.
>
>     libstdc++-v3/ChangeLog:
>
>             * include/bits/hashtable_policy.h
>             (_Hash_node_value_base<>::_M_valptr(),
> _Hash_node_value_base<>::_M_v())
>             Add [[__gnu__::__always_inline__]].
>             (_Hash_node<>::_M_next()): Add constexpr.
>
>     Co-authored-by: TC <rs2740@gmail.com>
>
> Ok to commit and backport to GCC 11, 12, 13 branches ?
>
> François
>
> [2. text/x-patch; pr111050.patch]...