kk: Support VK_EXT_post_depth_coverage

Requires slightly different declaration of sample mask input.

Reviewed-by: Aitor Camacho <aitor@lunarg.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/41283>

docs/features.txt

@@ -671,7 +671,7 @@ Khronos extensions that are not part of any Vulkan version:
   VK_EXT_pci_bus_info                                   DONE (anv, hasvk, nvk, radv, vn)
   VK_EXT_physical_device_drm                            DONE (anv, hasvk, hk, nvk, panvk, pvr, radv, tu, v3dv, vn)
   VK_EXT_pipeline_library_group_handles                 DONE (anv, lvp, radv, vn)
-  VK_EXT_post_depth_coverage                            DONE (anv/gfx11+, lvp, nvk, radv/gfx10+, tu, vn)
+  VK_EXT_post_depth_coverage                            DONE (anv/gfx11+, kk, lvp, nvk, radv/gfx10+, tu, vn)
   VK_EXT_present_timing                                 DONE (anv, hk, nvk, radv, tu, panvk)
   VK_EXT_primitive_restart_index                        DONE (lvp, radv)
   VK_EXT_primitive_topology_list_restart                DONE (anv, hasvk, lvp, nvk, panvk, radv, tu, v3dv, vn, nvk)

src/kosmickrisp/compiler/nir_to_msl.c

@@ -63,14 +63,27 @@ static const char *sysval_table[SYSTEM_VALUE_MAX] = {
       "uint mtl_AmplificationID [[amplification_id]]",
    [SYSTEM_VALUE_FIRST_VERTEX] = "uint gl_FirstVertex [[base_vertex]]",
 };
+static const char *sysval_sample_mask_in_post_depth_coverage =
+   "uint gl_SampleMask [[sample_mask, post_depth_coverage]]";
 
 static void
 emit_sysvals(struct nir_to_msl_ctx *ctx, nir_shader *shader)
 {
+   bool is_frag_with_post_depth_coverage =
+      ctx->shader->info.stage == MESA_SHADER_FRAGMENT &&
+      ctx->shader->info.fs.post_depth_coverage;
+
    unsigned i;
    BITSET_FOREACH_SET(i, shader->info.system_values_read, SYSTEM_VALUE_MAX) {
-      assert(sysval_table[i]);
-      P_IND(ctx, "%s,\n", sysval_table[i]);
+      const char *sysval;
+      if (is_frag_with_post_depth_coverage &&
+          i == SYSTEM_VALUE_SAMPLE_MASK_IN)
+         sysval = sysval_sample_mask_in_post_depth_coverage;
+      else
+         sysval = sysval_table[i];
+
+      assert(sysval);
+      P_IND(ctx, "%s,\n", sysval);
    }
 }
 

src/kosmickrisp/vulkan/kk_physical_device.c

@@ -147,6 +147,7 @@ kk_get_device_extensions(const struct kk_instance *instance,
       .EXT_load_store_op_none = true,
       .EXT_multi_draw = true,
       .EXT_mutable_descriptor_type = true,
+      .EXT_post_depth_coverage = true,
       .EXT_shader_atomic_float = true,
       .EXT_shader_replicated_composites = true,
       .EXT_shader_subgroup_ballot = true,