[Mesa-dev] [PATCH 00/17] Rework Mesa/ST shader compilation logic (Part 1)

Brian Paul brianp at vmware.com
Wed Oct 7 12:54:20 PDT 2015

On 10/07/2015 12:34 PM, Brian Paul wrote:
> On 10/05/2015 07:26 PM, Marek Olšák wrote:
>> Hi,
>> This is a start of reworking how st/mesa translates and creates
>> shaders. The result of this patch series is this:
>> In LinkShader or ProgramStringNotify, the shader is translated to TGSI
>> as-is. There are no shader code modifications for shader variants. The
>> glsl-to-tgsi visitor is released.
>> We can't release the GLSL IR at this point yet, because core Mesa
>> needs it for program resource queries at least.
>> That's the only place st/mesa interacts with Mesa IR and GLSL IR.
>> After that, it only works with the TGSI representation.
>> When we get to a draw call, tgsi_transform_shader is used to modify
>> shaders to produce shader variants. It does:
>> - feature emulation (color clamping, per-sample shading, edgeflags)
>> - adding glDrawPixels shader code
>> - adding glBitmap shader code
>> All the shader transformations are rewritten completely. There is no
>> patching with Mesa IR or glsl-to-tgsi anymore.
>> It shouldn't be so difficult to add support for some new IR or phase
>> out Mesa IR and GLSL IR support at some point.
>> The main motivations for this series are:
>> - translate to TGSI as soon as possible
>> - possibility to create gallium shaders after that if drivers don't
>> need many variants
>> - if variants are needed, the path to get them is much simpler
>> There will be part 2 when it's ready.
>> Please review. Thanks.
> I did a quick review and it looks good.  Some nice clean-ups for sure.
> Unfortunately, it looks like the conform drawpix.c test is now failing
> with this series.  It uses glPixelMap so maybe that's it.  I'll see if I
> can learn more.

Actually, it seems to be glDrawPixels(GL_STENCIL_INDEX) that's failing.

Piglit's ext_packed_depth_stencil-readdrawpixels is failing also.  Can 
you check that out?


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