[SPIR-V] Fix mesh payload global variable for VK_EXT_mesh_shaders #6526
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The existing logic from VK_NV_mesh_shader was incorrectly adapted for the VK_EXT_mesh_shader implementation when it comes to the handling of mesh payloads as in/out variables. Because TaskPayloadWorkgroupEXT must be applied to a single global OpVariable for each Task/Mesh shader, the struct should not be flattened. Further, as far as I can tell, Location assignment is not necessary for these input and output variables, so the usual reason for flattening structs does not apply. This change now removes the inner struct member global variables and ensures the parent payload is decorated with TaskPayloadWorkgroupEXT. Note that for amplification/task shaders, the payload variable is created with the groupshared decl, and then it's storage class needs to be updated when that variable is used as a parameter to the DispatchMesh call, as described in: https://docs.vulkan.org/spec/latest/proposals/proposals/VK_EXT_mesh_shader.html#_hlsl_changes Tested with updated spirv-val from: KhronosGroup/SPIRV-Tools#5640 Fixes microsoft#5981
Keenuts
approved these changes
Apr 16, 2024
cassiebeckley
approved these changes
Apr 17, 2024
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The existing logic from
VK_NV_mesh_shaderwas incorrectly adapted for theVK_EXT_mesh_shaderimplementation when it comes to the handling of payloads as in/out variables. BecauseTaskPayloadWorkgroupEXTmust be applied to a single globalOpVariablefor each task/mesh shader, the struct should not be flattened. Further, Location assignment is not necessary for these input and output variables, so the usual reason for flattening structs does not apply.This change now removes the inner struct member global variables and ensures the parent payload is decorated with
TaskPayloadWorkgroupEXT. Note that for amplification/task shaders, the payload variable is created with thegroupshareddecl, and then its storage class needs to be updated when that variable is used as a parameter to theDispatchMeshcall, as described in: https://docs.vulkan.org/spec/latest/proposals/proposals/VK_EXT_mesh_shader.html#_hlsl_changesTested with new validation checks from: KhronosGroup/SPIRV-Tools#5640
Fixes #5981