[PATCH v1 1/1] gas/write.c: add explicitly flag SEC_HAS_CONTENT to object attributes section

[Matthieu Longo]

On 2025-06-27 07:55, Jan Beulich wrote:
> On 25.06.2025 16:57, Matthieu Longo wrote:
>> The object attributes section:
>> - is readonly (SEC_READONLY=1).
>> - only contains data (SEC_DATA=1).
>> - does not require the OS to allocate space at runtime
>>    (SEC_ALLOC=0).
>> - does not require the OS to load the section at runtime
>>    (SEC_LOAD=0).
>> - is written out to the output object if it is not empty
>>    (SEC_HAS_CONTENT=1).
>>
>> Today, the setting of SEC_HAS_CONTENT (if not specified by
>> bfd_set_section_flags) occurs a few lines below inside
>> size_seg (see code below), the last function called in
>> create_obj_attrs_section().
>>
>> // If this section is not empty (size > 0) and this section
>> // is not .bss, the flag is set.
>>    if (size > 0 && ! seginfo->bss)
>>      flags |= SEC_HAS_CONTENTS;
>>
>> Setting the flag SEC_HAS_CONTENT via bfd_set_section_flags()
>> instead of relying on the hidden side-effect of size_seg()
>> seems a more maintainable approach due to its explicitness.
> 
> One can also look at this the other way around: It may be undue open-
> coding that you suggest to add. Look at maybe_generate_build_notes():
> It sets the flag unconditionally, but calls bfd_set_section_contents()
> only conditionally. If it (properly) left the setting of the flag to
> size_seg(), things would be more consistent overall. (And yes,
> create_obj_attrs_section() doesn't have this same issue as it checks
> for zero size early on. The more abstract open-coding aspect remains,
> though.)
> 
> Jan

If I put in parallel this function with maybe_generate_build_notes(), 
why is SEC_HAS_CONTENTS set explicitly and still size_seg() is called at 
the end ?

Regards,
Matthieu