[virglrenderer-devel] [PATCH 0/4] Refactor vrend_shader, part I

[Dave Airlie]

On 9 May 2018 at 09:17, Gurchetan Singh <gurchetansingh at chromium.org> wrote:
> On Tue, May 8, 2018 at 3:34 PM, Dave Airlie <airlied at gmail.com> wrote:
>> On 9 May 2018 at 05:06, Gurchetan Singh <gurchetansingh at chromium.org> wrote:
>>> This series is intended to have no functional impact. This mainly
>>> moves code around and adds a conversion table in attempt to:
>>>
>>> - Add some abstraction to our TGSI to GLSL logic.
>>> - Split up large functions.
>>>
>>> This was tested with the dEQP GLES3 suite, where no regressions were
>>> observed. This increases the overall code line count, but may make
>>> subsequent changes / refactors a little easier.
>>>
>>
>> I think these are mostly fine, however they are going to complicate landing
>> any of the work we have in branches quite heavily, we have fp64, most of
>> arb_gpu_shader5 and a chunk of gles3.1 sitting around, this will make
>> landing all of that a bit more work.
>>
>> I'm also not sure about the 3 srcs, I think there are 4 srcs TGSI instructions
>> in my gpu_shader5 (bitfieldInsert)
>
> Only 3 srcs is based on this blurb in the documentation -- "An opcode
> may have up to one destination register, known as dst, and between
> zero and three source registers, called src0 through src2".
> bitfieldInsert seems to use the destination as a source since it
> replaces "a bit region of ‘base’ with the low bits of ‘insert’":

Yeah unfortunately that's lies in the docs for bfi at least in the r600 driver
we access src[3]. tgsi_info_opcodes.h shows a few 4s in the number of
srcs fields.

>
> I've only looked at the GLES31 branch, and I think that would benefit
> from a clean-up before we try to land it.  Almost all the tests I ran
> failed, and many of errors were conversion related -- it could be
> useful to abstract them away.
>
> When do you expect the fp64 and arb_gpu_shader5 branches to land?  If
> they are in a better state and ready to go, it's reasonable to hold
> off on refactoring.
>

I've posted arb_gpu_shader5 now, it could probably do with some regression
testing on gles if anyone has time.

I can probably leave fp64 to afterwards, and my half done tess shaders
will probably be best to leave until afterwards.

Dave.