[LLVMdev] Validating LLVM

[Óscar Fuentes]

David Greene <dag at cray.com> writes:

> Back during the LLVM developer's meeting, I talked with some of you
> about a proposal to "validate" llvm.  Now that 2.4 is almost out the
> door, it seems a good time to start that discussion.

I applaud your initiative. Discussing this issue is badly needed. From
my point of view, LLVM still has an academical/exploratory character
that makes it incompatible with a long term commitment from the POV of
some industry users (those for whom LLVM would be a critical component)
unless those users have enough resources for maintaining their own LLVM
branch.

IMO a validation process based on running test suites is not enough. As
you know very well, tests can demonstrate failures, but can not
demonstrate correctness. An approach based on having stable (bug-fix
only) and development branches is more adequate. This way, each user can
devote work to validate LLVM for its own purposes, apply fixes to the
stable branch and then have some hope of achieving a point where LLVM is
good enough, instead of an endless upgrading where you fix known bugs
while knowing that new ones are being introduced.

This conflicts with current practice of going forward at full throttle,
when it is not rare that developers recommend using ToT just a few weeks
after a release.

Hopefully when clang matures new requirements on middle-term stability
will be enforced.

-- 
Oscar