[Mesa-dev] [RFC PATCH 00/16] A new IR for Mesa

[John Kessenich]

Hi,

If Mesa used an LLVM IR for it's shader compiler stack, it would most likely

   - Pick a specific shipped version.  Shipped versions are stable and
   unchanging.  Upgrading to a newer version would be done only by choice, on
   Mesa's schedule.
   - Not bring the source into mesa: it works perfectly well sitting next
   to Mesa.
   - Link it in statically so there are no distro/versioning issues and no
   interactions with other components of the system that independently use
   LLVM however they wish.  This is also quite small compared to other uses of
   LLVM people sometimes discuss.

Externally, no one could even tell some helper functions within the
compiler stack came from LLVM or a specific version of LLVM.

> Packaging and ABI stability...

These don't even exist with linking statically to a chosen version.

JohnK



On Tue, Aug 26, 2014 at 10:25 PM, Greg Fischer <greg at lunarg.com> wrote:

> My apologies for a too-brief response to this question.
>
> GlassyMesa links LLVM statically into Mesa. I believe that previous
> posters to this thread have already done a pretty good job of arguing that
> this is at least a workable approach.
>
> Best regards,
> Greg
>
>
>
> On Tue, Aug 26, 2014 at 7:14 PM, Kenneth Graunke <kenneth at whitecape.org>
> wrote:
>
>> On Tuesday, August 26, 2014 06:45:42 PM Greg Fischer wrote:
>> > The GlassyMesa effort is ongoing despite the lack of recent activity. We
>> > continue to embrace LLVM as a basis for shader compilation in Mesa and
>> > elsewhere.
>> >
>> > We agree that translating from LLVM back "up" to GLSL IR is problematic
>> and
>> > that an architecture that supports LLVM backends would be desirable.
>> >
>> > The current published code is a work-in-progress. We are currently
>> working
>> > on tuning of compilation time and code generation quality, and some of
>> that
>> > work will likely be appearing soon. There have also been recent
>> > improvements in glslang, the parser for this stack.
>> >
>> > Packaging and ABI stability have not been an issue for us.
>>
>> As far as I know, you haven't actually shipped your software in any Linux
>> distribution yet, so a lack of packaging problems sort of goes without
>> saying...
>>
>> --Ken
>
>
>
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