kk: enable shaderStencilExport

This requires a small new NIR pass to force the stencil output to be unsigned.

Reviewed-by: Aitor Camacho <aitor@lunarg.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38067>

src/kosmickrisp/compiler/msl_nir_lower_common.c

@@ -253,3 +253,31 @@ msl_nir_layer_id_type(nir_shader *nir)
    return nir_shader_intrinsics_pass(nir, msl_layer_id_uint, nir_metadata_all,
                                      NULL);
 }
+
+static bool
+stencil_type(nir_builder *b, nir_intrinsic_instr *intr, void *data)
+{
+   if (intr->intrinsic == nir_intrinsic_store_output &&
+       nir_intrinsic_io_semantics(intr).location == FRAG_RESULT_STENCIL) {
+      nir_alu_type type = nir_intrinsic_src_type(intr);
+      nir_intrinsic_set_src_type(
+         intr, nir_type_uint | nir_alu_type_get_type_size(type));
+      return true;
+   }
+   if (intr->intrinsic == nir_intrinsic_load_output &&
+       nir_intrinsic_io_semantics(intr).location == FRAG_RESULT_STENCIL) {
+      nir_alu_type type = nir_intrinsic_dest_type(intr);
+      nir_intrinsic_set_dest_type(
+         intr, nir_type_uint | nir_alu_type_get_type_size(type));
+      return true;
+   }
+   return false;
+}
+
+bool
+msl_nir_fix_stencil_type(nir_shader *nir)
+{
+   assert(nir->info.stage == MESA_SHADER_FRAGMENT);
+
+   return nir_shader_intrinsics_pass(nir, stencil_type, nir_metadata_all, NULL);
+}

src/kosmickrisp/compiler/nir_to_msl.h

@@ -54,3 +54,4 @@ bool msl_ensure_depth_write(nir_shader *nir);
 bool msl_ensure_vertex_position_output(nir_shader *nir);
 bool msl_nir_sample_mask_type(nir_shader *nir);
 bool msl_nir_layer_id_type(nir_shader *nir);
+bool msl_nir_fix_stencil_type(nir_shader *nir);

src/kosmickrisp/vulkan/kk_physical_device.c

@@ -107,6 +107,7 @@ kk_get_device_extensions(const struct kk_instance *instance,
       .EXT_pipeline_creation_feedback = true,
       .EXT_private_data = true,
       .EXT_shader_demote_to_helper_invocation = true,
+      .EXT_shader_stencil_export = true,
       .EXT_subgroup_size_control = true,
       .EXT_texel_buffer_alignment = false,
       .EXT_texture_compression_astc_hdr = false,

src/kosmickrisp/vulkan/kk_shader.c

@@ -407,6 +407,8 @@ kk_lower_fs(nir_shader *nir, const struct vk_graphics_pipeline_state *state)
    /* Metal's sample mask is uint. */
    NIR_PASS(_, nir, msl_nir_sample_mask_type);
 
+   NIR_PASS(_, nir, msl_nir_fix_stencil_type);
+
    if (state->ms && state->ms->rasterization_samples &&
        state->ms->sample_mask != UINT16_MAX)
       NIR_PASS(_, nir, msl_lower_static_sample_mask, state->ms->sample_mask);