From: Carlos O'Donell <carlos@redhat.com>
To: Zack Weinberg <zackw@panix.com>
Cc: Florian Weimer <fweimer@redhat.com>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: Are the pthread "compatibility" copies of symbols in libc still necessary?
Date: Fri, 16 Mar 2018 20:46:00 -0000 [thread overview]
Message-ID: <38c1d3b5-8e5b-3651-a344-c6c2ee47fb69@redhat.com> (raw)
In-Reply-To: <CAKCAbMjTb_cUYst+82SbhzAWF7i2oiSdNjFJvhPO=2H+LyNX=A@mail.gmail.com>
On 03/16/2018 12:13 PM, Zack Weinberg wrote:
> On Fri, Mar 16, 2018 at 1:38 PM, Carlos O'Donell <carlos@redhat.com> wrote:
>> On 03/16/2018 09:42 AM, Florian Weimer wrote:
>>> On 03/16/2018 04:35 PM, Carlos O'Donell wrote:
>>>>
>>>> The specification says the data must be recorded, but it doesn't say what you
>>>> have to *do* with the data?
>>>
>>> It does:
>>>
>>> â
>>> A fatal error shall be triggered when no matching definition can be
>>> found in the object whose name is the one referenced by the vn_name
>>> element in the Elfxx_Verneed entry.
>>> â
>>
>> I don't know what drove this requirement.
>>
>> From a first-principles perspective is doesn't seem to derive from any
>> foundational aspect of the linkage model.
>
> I don't claim to know what Ulrich was thinking at the time, but if you
> start from the premise that it would be more consistent in general if
> symbols always resolved at load time to the library they were found in
> at link time, then adding this requirement for versioned symbols can
> be seen as a way to introduce that consistency in a
> backward-compatible fashion. That said, without any way to declare
> that symbol X is _supposed_ to have moved from foo.so to bar.so, it
> puts us in a hole.
>
> This is a GNU spec, so we _could_ change it. We'd need to do a bit of
> formal consultation with everyone else who might be affected, but I
> don't think our hands should be tied by a decision that nobody
> remembers the original rationale for anymore.
I agree. I'd like to investigate changing this, but don't see myself
having the time to do so in the next 4-6 months, not at least until
2.28 is out the door (I'm the RM).
Cheers,
Carlos.
next prev parent reply other threads:[~2018-03-16 20:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 14:30 Zack Weinberg
2018-03-16 14:41 ` Florian Weimer
2018-03-16 15:35 ` Carlos O'Donell
2018-03-16 15:42 ` Florian Weimer
2018-03-16 17:39 ` Carlos O'Donell
2018-03-16 17:40 ` Florian Weimer
2018-03-16 18:13 ` Zack Weinberg
2018-03-16 20:46 ` Carlos O'Donell [this message]
2018-03-16 21:12 ` Zack Weinberg
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