[PATCH v0 11/15] bfd: merge duplicated subsections into one after parsing

[Jan Beulich]

On 10.03.2025 18:51, Matthieu Longo wrote:
> Several subsections with the same name can be present inside an object
> file depending on how it was generated. Gas won't generate such an
> object as it is able to detect scattered declaration of a subsection,
> and merge its content before the serialization. However, others
> assemblers than Gas might keep the subsections separated, and opted for
> delegating the merge to the linker.
> Additionally, a subsection can be populated before the parsing the
> attributes section if some GNU properties are convertible to build
> attributes.
> In order to make the merge logic between object files simpler, the
> deserializer is able to handle to perform an union of the duplicated
> subsections inside an object.
> Since the same deserializaton code is used by objcopy, it means that
> objcopy won't simply copy the data to the output object, but will also
> merge duplicated subsections together, so the readelf output between
> the two objects will be different. This might be seen as a bug but,
> given that gas will never generate such an object, I would argue that
> it is an acceptable design choice.

I tend to disagree: objcopy isn't linking. ld -r may do such combining,
but imo objcopy shouldn't.

Jan