Re: Define __start/__stop symbols when there is only a dynamic def

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Jan 26, 2018 at 8:52 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Jan 26, 2018 at 6:04 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Jan 26, 2018 at 5:43 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Fri, Jan 26, 2018 at 5:19 AM, Nick Clifton <nickc@redhat.com> wrote:
>>>> Hi Alan,
>>>>
>>>>> This patch fixes a case where a user had a C-representable named
>>>>> section in both the executable and shared libraries, and of course
>>>>> wanted the size of the local section in the executable, not the
>>>>> dynamic section.  It does mean that __start and __stop symbols don't
>>>>> behave exactly like PROVIDEd symbols, but I think that's a reasonable
>>>>> difference particularly since this is the way they used to behave.
>>>>
>>>> Is this distinction now documented ?  Ie can future users still be
>>>> confused by this behaviour ?
>>>>
>>>>> Nick, I'd like to apply this to the branch.  I think it should be
>>>>> quite safe.
>>>>>
>>>>>       * elflink.c (bfd_elf_define_start_stop): Override symbols when
>>>>>       they are defined dynamically.
>>>>
>>>> Fair enough - please apply - although I do also like H.J.'s request
>>>> for a testcase...
>>>>
>>>
>>> There are testcases for:
>>>
>>> https://sourceware.org/bugzilla/show_bug.cgi?id=21964
>>>
>>> But they only check __start/__stop symbols are handled correctly.
>>> __size isn't checked.   Let me see if I can extend them to check
>>> __size.
>>
>> It should be the ".sizeof." directive.  One thing which bothers me is
>> why __start/__stop are OK without the patch.  Why is it needed only
>> for ".sizeof."  I will find it out with the new testcase for ".sizeof.".
>>
>
> Something wrong with the ".sizeof." directive.  I opened a bug:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=22750
>

I don't quite understand what issues Alan's patch is trying to fix.
Alan, do you have a testcase to show that it fails without your
change?


-- 
H.J.