[Mesa-dev] [RFC] gallium/hud: fix issue w/ tgsi_to_nir

[Rob Clark]

tgsi.rst currently says:

----
If no ArrayID is specified with an indirect addressing operand the whole
register file might be accessed by this operand. This is strongly discouraged
and will prevent packing of scalar/vec2 arrays and effective alias analysis.
----

I'd be pretty happy to remove it and replace it w/ something to the
effect of indirect addressing where no ArrayID is specified is
undefined :-)

BR,
-R

On Wed, Jun 24, 2015 at 6:17 PM, Marek Olšák <maraeo at gmail.com> wrote:
> Indirect addressing without the ArrayID is undefined in the general
> case. You need the ArrayID to be able to tell where the array
> declaration starts and what its semantic name is.
>
> Marek
>
> On Wed, Jun 24, 2015 at 8:35 PM, Rob Clark <robdclark at gmail.com> wrote:
>> On Wed, Jun 24, 2015 at 12:31 PM, Marek Olšák <maraeo at gmail.com> wrote:
>>> Yes, ArrayID != 0 means it's an array, otherwise it's just a compact
>>> way to add declarations.
>>
>> ok.. hmm, I guess tgsi.rst needs an update then..
>>
>>> I recently added the array support for inputs and outputs, we just
>>> need to enable it on non-radeon non-swrast drivers:
>>> http://cgit.freedesktop.org/mesa/mesa/commit/?id=b6ebe7eabf54936a02acc0968e718e0c264a73f5
>>
>> ok, in principle (after fixing ttn based on the assumption that we
>> won't get indirect access if ArrayID==0, and now that tgsi f/e is
>> dropped) freedreno should be ok for array in/out's..  I'll enable the
>> cap and see what happens after fixing ttn and debugging some indirect
>> issues (seems either there is something I don't understand about the
>> hw yet, or maybe an a4xx bug.. right now shaders that I think should
>> work aren't and I'm in android hell trying to get some more traces
>> from blob :-/)
>>
>> BR,
>> -R
>>
>>> It would be nice to enable the arrays on all drivers instead of
>>> working around it indefinitely.
>>>
>>> Marek
>>>
>>> On Wed, Jun 24, 2015 at 1:31 PM, Rob Clark <robdclark at gmail.com> wrote:
>>>> Ok, I *thought* we didn't get ArrayID on IN/OUT, but only TEMP?  If it
>>>> is safe to assume that we always get ArrayID that makes it much
>>>> easier.
>>>>
>>>> BR,
>>>> -R
>>>>
>>>> On Wed, Jun 24, 2015 at 5:39 AM, Marek Olšák <maraeo at gmail.com> wrote:
>>>>> It's not an array, because the ArrayID is 0. It's a valid non-array
>>>>> declaration. If any TGSI user doesn't understand it, that user should
>>>>> be fixed.
>>>>>
>>>>> Marek
>>>>>
>>>>> On Tue, Jun 23, 2015 at 3:20 PM, Rob Clark <robdclark at gmail.com> wrote:
>>>>>> From: Rob Clark <robclark at freedesktop.org>
>>>>>>
>>>>>> Ok, so actually there is a ttn issue here to fix as well.. but it
>>>>>> brought up a question in my mind.  When ttn sees something like
>>>>>>
>>>>>>   DCL IN[0..1]
>>>>>>
>>>>>> it will treat that as an array (which in the end will result in
>>>>>> constraints about where the registers get allocated.  Which is not
>>>>>> really ideal.
>>>>>>
>>>>>> With glsl we don't actually get input arrays (but instead a bunch
>>>>>> of MOV's to a TEMP array) currently.  So I'm not quite sure how
>>>>>> an actual input array should look.  (But my preference would be
>>>>>> IN[a..b] for arrays and IN[c] otherwise)
>>>>>> ---
>>>>>>  src/gallium/auxiliary/hud/hud_context.c | 3 ++-
>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/src/gallium/auxiliary/hud/hud_context.c b/src/gallium/auxiliary/hud/hud_context.c
>>>>>> index 6a124f7..2b6d3a7 100644
>>>>>> --- a/src/gallium/auxiliary/hud/hud_context.c
>>>>>> +++ b/src/gallium/auxiliary/hud/hud_context.c
>>>>>> @@ -1163,7 +1163,8 @@ hud_create(struct pipe_context *pipe, struct cso_context *cso)
>>>>>>     {
>>>>>>        static const char *vertex_shader_text = {
>>>>>>           "VERT\n"
>>>>>> -         "DCL IN[0..1]\n"
>>>>>> +         "DCL IN[0]\n"
>>>>>> +         "DCL IN[1]\n"
>>>>>>           "DCL OUT[0], POSITION\n"
>>>>>>           "DCL OUT[1], COLOR[0]\n" /* color */
>>>>>>           "DCL OUT[2], GENERIC[0]\n" /* texcoord */
>>>>>> --
>>>>>> 2.4.3
>>>>>>
>>>>>> _______________________________________________
>>>>>> mesa-dev mailing list
>>>>>> mesa-dev at lists.freedesktop.org
>>>>>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev