[Mesa-dev] [RFCv0 0/8] gallium: add support for NIR as alternate IR

Ilia Mirkin imirkin at alum.mit.edu
Tue Oct 20 08:17:02 PDT 2015

On Tue, Oct 20, 2015 at 9:10 AM, Marek Olšák <maraeo at gmail.com> wrote:
> On Tue, Oct 20, 2015 at 2:37 PM, Rob Clark <robdclark at gmail.com> wrote:
>> On Tue, Oct 20, 2015 at 6:49 AM, Marek Olšák <maraeo at gmail.com> wrote:
>>> On Tue, Oct 20, 2015 at 3:51 AM, Rob Clark <robdclark at gmail.com> wrote:
>>>> On Mon, Oct 19, 2015 at 8:53 PM, Marek Olšák <maraeo at gmail.com> wrote:
>>>>> Yes, drivers need to "dup" tokens if they want to keep them. Their
>>>>> lifetime is the create function and that's it. st/mesa only keeps the
>>>>> tokens for vertex shaders, because it needs for emulating some
>>>>> features with the Draw module.
>>>> It is something that I think would be worth revisiting, since the
>>>> common case is that drivers have to dup the tokens to do their own
>>>> variant mgmt.. so that seems like the better case to optimize for.  I
>>>> think the only one that isn't doing it's own variant mgmt is nouveau,
>>>> but Ilia mentioned at some point that there where some edge cases
>>>> where they really do need a variant.
>>> This would add more cruft into state trackers and modules. Doing "dup"
>>> in the driver is the easiest way to handle this.
>>> Also, drivers should be able to release any incoming IR if they don't
>>> need it. Including NIR. Having a requirement that some IR must be in
>>> memory for the lifetime of shaders is just overall a bad idea.
>> If you need to create variants, you need to hang on to the IR until
>> all possible variants are created (ie. forever)
> Not true. You can convert to another IR, run lowering passes, and keep
> the result of that.

On nvc0, I'm just patching up the binary code directly. I may or may
not be able to get away with doing that on nv50... my latest thinking
is that I can, but haven't implemented yet. Which will mean no
variants for nouveau *and* fully working logic for flat shading :)


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