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From: Jonathan Wakely <>
To: "François Dumont" <>
Cc: "libstdc++" <>,
	gcc-patches <>,
Subject: Re: [PATCH] [11/12/13/14 Regression] ABI break in _Hash_node_value_base since GCC 11 [PR 111050]
Date: Mon, 11 Sep 2023 12:51:18 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Sun, 10 Sept 2023 at 14:57, François Dumont via Libstdc++
<> wrote:
> 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 ?

Sam already explained that, but please check with Tim how he wants to
be credited, if at all. He doesn't have a copyright assignment, and
hasn't added a DCO sign-off to the patch, but it's small enough to not
need it as this is the first contribution credited to him.

>      libstdc++: Add constexpr qualification to _Hash_node::_M_next()

What has this constexpr addition got to do with the ABI change and the
always_inline attributes?

It certainly doesn't seem like it should be the summary line of the
git commit message.

>      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 <>
> Ok to commit and backport to GCC 11, 12, 13 branches ?
> François

  parent reply	other threads:[~2023-09-11 11:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-10 13:56 François Dumont
2023-09-10 15:36 ` Sam James
2023-09-11 11:51 ` Jonathan Wakely [this message]
2023-09-11 17:19   ` François Dumont
2023-09-12 16:09     ` Jonathan Wakely
2023-09-14  4:46       ` François Dumont
2023-09-27  4:44         ` François Dumont
2023-09-28 16:18           ` Jonathan Wakely
2023-09-28 17:25             ` François Dumont
2023-09-29  9:53               ` Jonathan Wakely
2023-10-02 20:51                 ` François Dumont

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