[LLVMdev] Clarification on the backward compatibility promises

[Eric Christopher]

>> 2. Metadata compatibility. We already had precedence of introducing
>> incompatible changes into metadata format in the past within release.
>> Should we use relaxes rules for metadata compatibility?
>
> I think we have a special case for debug metadata (and should document
> that), but otherwise I think we should hold metadata to the same
> standard as the rest of the IR.
>

The idea with metadata is that it can be removed and everything still
works. I'm definitely not ready to lock down the debug metadata format
and I really don't think we should for any of the other uses since
stripping already works. (Note, I don't consider function attributes
etc as metadata)

-eric