build-ids, .debug_sup and other IDs (Was: [PATCH] Handle DWARF 5 separate debug sections)

[Frank Ch. Eigler]

Hi -

> I'm concerned about using dwo IDs to index debuginfod. They are only
> 64-bits and there will be many more dwo IDs than build ids or
> supplemental file ids [...]

AIUI, -gsplit-dwarf is more suitable for development/scratch builds
than for distro binaries.  If distros agree, then I would not expect
.dwo files to show up in distro-wide debuginfod services, but rather
within developers' own build trees.  Then debuginfod indexing
collisions would only be a risk within a particular local set of trees
(if serviced by a local debuginfod), rather than distro wide or wider.

> What about using `/buildid/BUILDID/dwp` instead? This is not a
> perfect solution, since (currently) no one puts the build-id into
> the *.dwp file, but it does get around this collision problem.

The hypothetical problem is collision between dwo/dwp files, not
between dwo/dwp and normal buildid dwarf files, right?  In that case,
are you talking about two levels of indexing (buildid of final linked
binary + dwo_id)?  That would resemble the indexing work required from
debuginfod to match up binaries with their source files plus binaries
with dwz supplemental files).

- FChE