[llvm-dev] [cfe-dev] What version comes after 3.9? (Was: [3.9 Release] Release plan and call for testers)

[Hal Finkel via llvm-dev]

----- Original Message -----
> From: "Hans Wennborg via cfe-dev" <cfe-dev at lists.llvm.org>
> To: "llvm-dev" <llvm-dev at lists.llvm.org>, "cfe-dev" <cfe-dev at lists.llvm.org>, "LLDB Dev" <lldb-dev at lists.llvm.org>,
> "openmp-dev (openmp-dev at lists.llvm.org)" <openmp-dev at lists.llvm.org>
> Cc: "r jordans" <r.jordans at tue.nl>, "Paul Robinson" <Paul_Robinson at playstation.sony.com>
> Sent: Monday, June 13, 2016 6:54:19 PM
> Subject: [cfe-dev] What version comes after 3.9? (Was: [3.9 Release] Release plan and call for testers)
> 
> Breaking this out into a separate thread since it's kind of a
> separate
> issue, and to make sure people see it.
> 
> If you have opinions on this, please chime in. I'd like to collect as
> many arguments here as possible to make a good decision. The main
> contestants are 4.0 and 3.10, and I've seen folks being equally
> surprised by both.
> 
> Brain-dump so far:
> 
> - After LLVM 1.9 came 2.0, and after 2.9 came 3.0; naturally, 4.0
> comes after 3.9.
> 
> - There are special bitcode stability rules [1] concerning major
> version bumps. 2.0 and 3.0 had major IR changes, but since there
> aren't any this time, we should go to 3.10.
> 
> - The bitcode stability rules allow for breakage with major versions,
> but it doesn't require it, so 4.0 is fine.
> 
> - But maybe we want to save 4.0 for when we do have a significant IR
> change?

I think that this is the right approach, and we happen to have a natural forcing function here: opaque pointer types. I think we should increment the major version number when opaque pointer types are here, as it will be a major breaking change, and then we'll have a version 4.0. Until then, unless something else breaking comes up, 3.10 sounds fine to me.

 -Hal

> 
> - We've never had an x.10 version before; maybe that would be
> confusing? Perhaps it's simply time to move on (like Linux 2.6.39 ->
> 3.0 and 3.19 -> 4.0).
> 
> - Since we do time-based rather than feature-based releases, the
> major
> version number shouldn't mean anything special anyway (e.g. big IR
> changes or not), so 4.0?
> 
> - Everyone knows that after 9 comes 10, so 3.10 it is. The version is
> a tuple after all.
> 
> - Let's go for 4.0 now, and 5.0 after that. Then the "dot"-releases
> in
> between would correspond to minor version bumps, which would make
> sense (and catch up with GCC!).
> 
> - It's just a number, no big deal; flip a coin or something.
> 
> What do you think?
> 
>  - Hans
> 
> 
>  [1].
>  http://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility
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-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory