Tag for using git describe on master

As first discussed in the giant "New LLVM git repository conversion
prototype" thread, I've pushed a git tag that allows git-describe to
be used for generating human readable commit names on master.

The tag is "llvmorg-10-init", to be interpreted as "the initial commit
with major version number 10". The idea is to add similar tags along
with future version bumps.

git describe generates a name like this:

$ git describe a4783ef

Where "llvmorg-10-init" is the tag name, 8348 is the number of commits
since the tag (yay, monotonically incrementing commit numbers), and
"a4783ef58d3" is the hash with "g" as a magic prefix to indicate it's
a git hash.

The name can be used to refer to commits directly (git only looks at
the hash after the "g"):

$ git show llvmorg-10-init-8348-ga4783ef58d3 -s --oneline
a4783ef58d3 [Alignment][NFC] getMemoryOpCost uses MaybeAlign


Thanks Hans!

Is this something that we can document somewhere? (especially if we will continue to maintain / create tags with each branching).

Sure, the question is where :slight_smile: Do we have a doc describing our git
setup somewhere?

(Currently traveling, slow to reply.)

Will the use of `git describe` output become required anywhere? Or will normal git hashes always be acceptable? I ask because people sometimes pass --no-tags to git-clone, etc.

I don't imagine it would become required anywhere. Git hashes are the
source of truth.