[cfe-dev] [LLVMdev] LLVM 3.4 Branch Freeze

[Hal Finkel]

----- Original Message -----
> From: "Pau Garcia i Quiles" <pgquiles at elpauer.org>
> To: "Hal Finkel" <hfinkel at anl.gov>
> Cc: "Tom Stellard" <tom at stellard.net>, "Óscar Fuentes" <ofv at wanadoo.es>, cfe-dev at cs.uiuc.edu, llvmdev at cs.uiuc.edu
> Sent: Thursday, December 19, 2013 1:55:12 PM
> Subject: Re: [LLVMdev] [cfe-dev] LLVM 3.4 Branch Freeze
> 
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> On Thu, Dec 19, 2013 at 8:15 PM, Hal Finkel < hfinkel at anl.gov >
> wrote:
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> > > > the other thing we need to determine is
> > > > whether or not we want to maintain a stable ABI for the bugfix
> > > > releases.
> > > > With 3.3, the plan was to have a stable ABI, but this caused me
> > > > to reject several fixes. I would recommend relaxing this
> > > > requirement if there is are bugfix releases for 3.4, but I'd
> > > > like to hear
> > > > what other people think about this.
> > > 
> > > What kinds of changes were made? (can you provide a couple of
> > > examples)?
> > > 
> > 
> > Here are a few examples:
> > http://comments.gmane.org/gmane.comp.compilers.llvm.cvs/157018
> 
> I think that we should keep source compatibility, not necessarily
> binary compatibility, in maintenance releases. Binary compatibility,
> when possible, is nice, but should not stand in the way of the bug
> fixes themselves.
> 
> Some of the packagers should comment on this topic :)
> 
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> Breaking ABI in patch releases with no other changes?
> 
> 
> As a Debian packager (but not LLVM packager), I am opposed to
> changing ABI without bumping soversion and changing library name. If
> we have this:
> 
> 
> LLVM 3.4.0 => libclang-3.4.so.1
> LLVM 3.4.1 => libclang-3.4.so.1 (same)
> 
> 
> but they are ABI-incompatible, that's going to cause trouble.
> 
> 
> But if we have this:
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> LLVM 3.4.0 => libclang-3.4.so.1
> LLVM 3.4.1 => libclang-3.4.so.2 (soname bumped)
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> that's perfectly fine
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> (I guess everybody here knew that already...)

This is a good point. I had assumed that we'd bump the soname for the maintenance releases (leaving patch-level changes to the packagers/distributors), but we should have an explicit policy on that.

 -Hal

> 
> --
> Pau Garcia i Quiles
> http://www.elpauer.org
> (Due to my workload, I may need 10 days to answer)

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory