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Commit 4a408ff7 authored by Pierre Moreau's avatar Pierre Moreau Committed by Marge Bot
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spirv: Ignore WorkgroupSize in non-compute stages


If a SPIR-V module contains for example both a geometry and a compute
shader, when processing the geometry shader its vertices out, input
primitive and output primitive attributes would get overwritten by the
value of the WorkgroupSize.

```
; SPIR-V
; Version: 1.5
; Generator: Khronos; 17
; Bound: 12
; Schema: 0
               OpCapability Geometry
               OpCapability Shader
          %1 = OpExtInstImport "GLSL.std.450"
               OpMemoryModel Logical GLSL450
               OpEntryPoint Geometry %main "main"
               OpEntryPoint GLCompute %main_0 "main"
               OpExecutionMode %main InputPoints
               OpExecutionMode %main Invocations 1
               OpExecutionMode %main OutputTriangleStrip
               OpExecutionMode %main OutputVertices 4
               OpExecutionMode %main_0 LocalSize 1 1 1
               OpSource GLSL 460
               OpSource GLSL 460
               OpName %main "main"
               OpName %main_0 "main"
               OpModuleProcessed "Linked by SPIR-V Tools Linker"
               OpDecorate %gl_WorkGroupSize BuiltIn WorkgroupSize
       %void = OpTypeVoid
          %6 = OpTypeFunction %void
       %uint = OpTypeInt 32 0
     %v3uint = OpTypeVector %uint 3
     %uint_1 = OpConstant %uint 1
%gl_WorkGroupSize = OpConstantComposite %v3uint %uint_1 %uint_1 %uint_1
       %main = OpFunction %void None %6
         %10 = OpLabel
               OpReturn
               OpFunctionEnd
     %main_0 = OpFunction %void None %6
         %11 = OpLabel
               OpReturn
               OpFunctionEnd
```

Running spirv_to_nir on the SPIR-V sample above and for the geometry
entry point would say that (among others):

* vertices out: 1
* input primitive: LINES
* output primitive: LINES

By removing any reference to `%gl_WorkGroupSize`, the output would
change to (among others):

* vertices out: 4
* input primitive: POINTS
* output primitive: TRIANGLE_STRIP

Fixes: 7d862ef5 ("spirv: Rework handling of spec constant workgroup size built-ins")

v2:
* Move the check from inside `handle_workgroup_size_decoration_cb()` to
  its caller (Caio Marcelo de Oliveira Filho )
* Add an assert on the shader stage before using
  `workgroup_size_builtin` (Caio Marcelo de Oliveira Filho )

Reviewed-by: default avatarCaio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Signed-off-by: default avatarPierre Moreau <dev@pmoreau.org>
Part-of: <mesa/mesa!9418>
parent 5fee362f
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