[Mesa-dev] How to know which exact llvm version to build/link against?

[Andrew A.]

On Wed, Feb 7, 2018 at 1:37 AM, Michel Dänzer <michel at daenzer.net> wrote:
> For a non-current snapshot of Mesa Git master, one may have to find an
> LLVM SVN snapshot from around the same time.

Just so I understand, a statement like "Try repro'ing the bug in svn
commit x of mesa from last year" doesn't wind up being very precise,
since the llvm version used by the author of commit x was never
documented/codified anywhere. Do you suppose there could be value in
codifying this a bit more? Perhaps some kind of client-side pre-commit
hook could notate the llvm version/commit/tag somewhere in the mesa
checkin...

I realize the same criticism could be made of not tracking version
numbers of other dependencies (e.g. "By that logic, everything is
imprecise, and all dependencies should be tracked in this manner,
including glibc, binutils, etc! A bit ridiculous!"), but as you
mention llvm is uniquely very unstable as an API, so there may be more
value in tracking it than other kinds of deps.

As a relatively infrequent user of mesa git checkouts, I can only say
that finding the correct llvm version to build against can be a bit of
a pain. As mentioned, I usually have to try several different llvm
checkouts before finding the right one. Even when I do get it working,
I still have no idea if that's the llvm version that the author of the
mesa commit was using (which I'd really prefer). Is this somehow not a
regular problem for mesa developers? Wondering if I'm blowing it out
of proportion.

Thanks.