[Mesa-dev] [PATCH] spirv: Add SpvCapabilityShaderViewportIndexLayerEXT

[Caio Marcelo de Oliveira Filho]

This capability allows gl_ViewportIndex and gl_Layer to also be used
as outputs in Vertex and Tesselation shaders.

v2: Make conditional to the capability, add gl_Layer, add tesselation
    shaders. (Iago)

v3: Don't export to tesselation control shader.

v4: Add Reviewd-by tag.

Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>
---

Iago, I don't have write access to the repository. Could you apply
this?

 src/compiler/shader_info.h         | 1 +
 src/compiler/spirv/spirv_to_nir.c  | 4 ++++
 src/compiler/spirv/vtn_variables.c | 8 ++++++++
 3 files changed, 13 insertions(+)

diff --git a/src/compiler/shader_info.h b/src/compiler/shader_info.h
index e7fd7dbe62..2fcbde74be 100644
--- a/src/compiler/shader_info.h
+++ b/src/compiler/shader_info.h
@@ -43,6 +43,7 @@ struct spirv_supported_capabilities {
    bool multiview;
    bool variable_pointers;
    bool storage_16bit;
+   bool shader_viewport_index_layer;
 };
 
 typedef struct shader_info {
diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index c6df764682..fdb2993db5 100644
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -3203,6 +3203,10 @@ vtn_handle_preamble_instruction(struct vtn_builder *b, SpvOp opcode,
          spv_check_supported(storage_16bit, cap);
          break;
 
+      case SpvCapabilityShaderViewportIndexLayerEXT:
+         spv_check_supported(shader_viewport_index_layer, cap);
+         break;
+
       default:
          vtn_fail("Unhandled capability");
       }
diff --git a/src/compiler/spirv/vtn_variables.c b/src/compiler/spirv/vtn_variables.c
index 7e8a090add..11d2aabac8 100644
--- a/src/compiler/spirv/vtn_variables.c
+++ b/src/compiler/spirv/vtn_variables.c
@@ -1187,6 +1187,10 @@ vtn_get_builtin_location(struct vtn_builder *b,
          *mode = nir_var_shader_in;
       else if (b->shader->info.stage == MESA_SHADER_GEOMETRY)
          *mode = nir_var_shader_out;
+      else if (b->options && b->options->caps.shader_viewport_index_layer &&
+               (b->shader->info.stage == MESA_SHADER_VERTEX ||
+                b->shader->info.stage == MESA_SHADER_TESS_EVAL))
+         *mode = nir_var_shader_out;
       else
          vtn_fail("invalid stage for SpvBuiltInLayer");
       break;
@@ -1194,6 +1198,10 @@ vtn_get_builtin_location(struct vtn_builder *b,
       *location = VARYING_SLOT_VIEWPORT;
       if (b->shader->info.stage == MESA_SHADER_GEOMETRY)
          *mode = nir_var_shader_out;
+      else if (b->options && b->options->caps.shader_viewport_index_layer &&
+               (b->shader->info.stage == MESA_SHADER_VERTEX ||
+                b->shader->info.stage == MESA_SHADER_TESS_EVAL))
+         *mode = nir_var_shader_out;
       else if (b->shader->info.stage == MESA_SHADER_FRAGMENT)
          *mode = nir_var_shader_in;
       else
-- 
2.16.2