[Mesa-dev] Mesa (master): tgsi: collect texture sampler target info in tgsi_scan_shader()

[Brian Paul]

On 03/30/2016 02:06 AM, Michel Dänzer wrote:
>
> Hi Brian,
>
>
> On 30.03.2016 09:16, Brian Paul wrote:
>> Module: Mesa
>> Branch: master
>> Commit: 86e1768c13d67945f4a9549820e711b70ff2aba7
>> URL:    https://urldefense.proofpoint.com/v2/url?u=http-3A__cgit.freedesktop.org_mesa_mesa_commit_-3Fid-3D86e1768c13d67945f4a9549820e711b70ff2aba7&d=BQIDaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=T0t4QG7chq2ZwJo6wilkFznRSFy-8uDKartPGbomVj8&m=tiYjpRoSC47n41zxrMyY1Jsj7UQ_2gQPU21sKYZu-YY&s=ywQlr5JK7Hk_Wy0Lqe78yOW0xVRW50zZxf4nyzeRRhY&e=
>>
>> Author: Brian Paul <brianp at vmware.com>
>> Date:   Sat Mar 26 11:46:53 2016 -0600
>>
>> tgsi: collect texture sampler target info in tgsi_scan_shader()
>>
>> Texture sample instructions specify a sampler unit and texture target
>> such as "1D", "2D", "CUBE", etc.  Sampler view declarations also specify
>> the sampler unit and texture target.
>>
>> This patch checks that the texture instructions agree with the declarations
>> and collects the texture target type for each sampler unit.
>>
>> v2: only compare instruction's texture target to the sampler view declaration
>> target if the instruction is a TEX instruction, not a SAMPLE instruction.
>>
>> Reviewed-by: José Fonseca <jfonseca at vmware.com>
>> Reviewed-by: Roland Scheidegger <sroland at vmware.com>
>
> [...]
>
>> @@ -431,6 +453,16 @@ scan_declaration(struct tgsi_shader_info *info,
>>            }
>>         } else if (file == TGSI_FILE_SAMPLER) {
>>            info->samplers_declared |= 1 << reg;
>> +      } else if (file == TGSI_FILE_SAMPLER_VIEW) {
>> +         unsigned target = fulldecl->SamplerView.Resource;
>> +         assert(target < TGSI_TEXTURE_UNKNOWN);
>> +         if (info->sampler_targets[reg] == TGSI_TEXTURE_UNKNOWN) {
>> +            /* Save sampler target for this sampler index */
>> +            info->sampler_targets[reg] = target;
>> +         } else {
>> +            /* if previously declared, make sure targets agree */
>> +            assert(info->sampler_targets[reg] == target);
>> +         }
>
> This broke a bunch of arb_gpu_shader5 piglit tests for me, e.g.
> spec at arb_gpu_shader5@texturegather at fs-r-none-shadow-2d:
>
> textureGather: ../../../../src/gallium/auxiliary/tgsi/tgsi_scan.c:206:
> scan_instruction: Assertion `info->sampler_targets[index] == target' failed.
>
> This is the TGSI:
>
> FRAG
> PROPERTY FS_COLOR0_WRITES_ALL_CBUFS 1
> DCL SV[0], POSITION
> DCL OUT[0], COLOR
> DCL SAMP[0]
> DCL SVIEW[0], SHADOW2D, FLOAT
> DCL CONST[1]
> DCL TEMP[0]
> DCL TEMP[1..2], LOCAL
> IMM[0] INT32 {0, 0, 0, 0}
> IMM[1] FLT32 {    0.5000,     0.0000,     0.0000,     0.0000}
>    0: MOV TEMP[0], SV[0]
>    1: MAD TEMP[0].y, SV[0], CONST[1].xxxx, CONST[1].yyyy
>    2: TXQ TEMP[1].xy, IMM[0].xxxx, SAMP[0], 2D
>    3: I2F TEMP[1].xy, TEMP[1].xyyy
>    4: RCP TEMP[2].x, TEMP[1].xxxx
>    5: RCP TEMP[2].y, TEMP[1].yyyy
>    6: MUL TEMP[1].xy, TEMP[0].xyyy, TEMP[2].xyyy
>    7: MOV TEMP[1].xy, TEMP[1].xyyy
>    8: MOV TEMP[1].z, IMM[1].xxxx
>    9: TG4 TEMP[1], TEMP[1], IMM[0].xxxx, SAMP[0], SHADOW2D
>   10: MOV OUT[0], TEMP[1]
>   11: END
>
>
> The problem is that the TXQ instruction (generated from GLSL
> textureSize) uses 2D as the target, but the sampler view is declared as
> SHADOW2D.
>
> I'm not sure if this is a bug in glsl_to_tgsi or the GLSL compiler, or
> if scan_declaration needs to be relaxed.

In st_glsl_to_tgsi.cpp it looks like we don't have the info to emit the 
TXQ instruction with a SHADOW2D texture target.

I think the simplest thing would be to skip TXQ, TXQS, LODQ and TXQ_LZ 
instructions there.

I'll post a patch...

-Brian