[PATCH v3] elf: Don't set its DT_VERSYM entry for unversioned symbol

[Jan Beulich]

On 31.10.2025 09:33, H.J. Lu wrote:
> On Fri, Oct 31, 2025 at 4:25 PM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> On 31.10.2025 09:20, H.J. Lu wrote:
>>> On Fri, Oct 31, 2025 at 3:48 PM Jan Beulich <jbeulich@suse.com> wrote:
>>>>
>>>> On 31.10.2025 00:21, H.J. Lu wrote:
>>>>> On Thu, Oct 30, 2025 at 10:27 PM Jan Beulich <jbeulich@suse.com> wrote:
>>>>>>
>>>>>> On 29.10.2025 03:09, H.J. Lu wrote:
>>>>>>> On Wed, Oct 29, 2025 at 9:54 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>>>
>>>>>>>> Undefined symbol without version shouldn't have the BASE version in its
>>>>>>>> DT_VERSYM entry.  Instead its DT_VERSYM entry should be all zero to
>>>>>>>> indicate that the symbol doesn't have a version.
>>>>>>>>
>>>>>>>> bfd/
>>>>>>>>
>>>>>>>> PR ld/33577
>>>>>>>> * elflink.c (elf_link_output_extsym): Don't set its DT_VERSYM
>>>>>>>> entry for unversioned symbol.
>>>>>>>>
>>>>>>>> ld/
>>>>>>>>
>>>>>>>> PR ld/33577
>>>>>>>> * testsuite/ld-elf/undefined.d: New file.
>>>>>>>> * testsuite/ld-elf/undefined.map: Likewise.
>>>>>>>> * testsuite/ld-elf/undefined.s: Likewise.
>>>>>>>>
>>>>>>>> OK for master?
>>>>>>>
>>>>>>> Here is the v2 patch to only check undefined symbols.
>>>>>>
>>>>>> Just one question: Wouldn't the new testcase be a better fit in ld-elfvers/?
>>>>>> If you agree, okay with it moved there.
>>>>>
>>>>> Here is the v3 patch with updated tests in ld-elfvers.   I also updated
>>>>> elf_link_output_extsym to handle defined symbol without version with
>>>>> a test.
>>>>
>>>> I'm irritated by you now altering an existing test, but there being no
>>>> new test anymore. Can you clarify this for me, please?
>>>
>>> My patch changes the linker behavior which results in the output  change
>>> of
>>>
>>> # objdump --dynamic-syms tmpdir/vers16
>>>
>>> since the "Base" version is no longer added to show_bar and show_foo
>>> which are unversioned symbols.   I have to change ld-elfvers/vers16.dsym.
>>
>> Right, but why did the earlier new testcase disappear?
> 
> The new behavior has been verified by the updated ld-elfvers/vers16.dsym.
> show_bar is a defined symbol without version and show_foo is an undefined
> symbol without version.   These are 2 cases which my updated patch covers
> No need for new tests.

Hmm, still puzzling me. Irrespective - I thought I somewhat understood the v2
change. I fear I don't understand the v3 change, no matter that I agree with
the change to the testcase expectations. I.e. it's the "how" that I'm in
trouble with, not the ultimate result. Hence I don't feel capable of
approving this change, sorry.

Jan