Re: [PATCH v2 3/4] configure: Disable lazy binding by default

[Siddhesh Poyarekar <siddhesh@sourceware.org>]

On 2023-07-17 11:30, Florian Weimer via Libc-alpha wrote:
> * Siddhesh Poyarekar:
> 
>> On 2023-07-13 05:38, Florian Weimer via Libc-alpha wrote:
>>> * Siddhesh Poyarekar via Libc-alpha:
>>>
>>>> +‘--disable-bind-now’
>>>> +     Enable lazy binding for installed shared objects and programs.
>>>> +     Lazy binding may improve program load times but it will disable
>>>> +     security hardening that enables full RELRO and a read-only global
>>>> +     offset table (GOT).
>>> This description is not correct because as far as I can see,
>>> --disable-bind-now does not enable lazy binding if the toolchain or the
>>> build flags default to it.
>>> I think we should remove this flag, rather than making
>>> --disable-bind-now work as documented.
>>
>> I feel like this needs more thought either way then, no point blocking
>> 2.38 for it.  What's the use case for lazy binding?  Are people
>> actually using this in the wild and would we be breaking things for
>> them?
> 
> I don't think it matters.  We have very few symbols that can be bound
> lazily.  Most symbolic bindings are against data symbols, which cannot
> be bound lazily, so the performance win for glibc itself is minuscule.
> 
> I think it may have been beneficial before we had the libc_hidden
> mechanism.  I suppose libpthread integration also helped to decreasing
> binding overhead.

Fair enough, I'll respin this by dropping the option and let Andreas 
decide if it's suitable for 2.38.  If not, I'll just queue it up for 2.39.

Thanks,
Sid