spirv: Propagate explicit layout only in types that need it

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5511>

src/compiler/spirv/spirv_to_nir.c

@@ -775,6 +775,33 @@ wrap_type_in_array(const struct glsl_type *type,
                           glsl_get_explicit_stride(array_type));
 }
 
+static bool
+vtn_type_needs_explicit_layout(struct vtn_builder *b, enum vtn_variable_mode mode)
+{
+   /* For OpenCL we never want to strip the info from the types, and it makes
+    * type comparisons easier in later stages.
+    */
+   if (b->options->environment == NIR_SPIRV_OPENCL)
+      return true;
+
+   switch (mode) {
+   case vtn_variable_mode_input:
+   case vtn_variable_mode_output:
+      /* Layout decorations kept because we need offsets for XFB arrays of
+       * blocks.
+       */
+      return b->shader->info.has_transform_feedback_varyings;
+
+   case vtn_variable_mode_ssbo:
+   case vtn_variable_mode_phys_ssbo:
+   case vtn_variable_mode_ubo:
+      return true;
+
+   default:
+      return false;
+   }
+}
+
 const struct glsl_type *
 vtn_type_get_nir_type(struct vtn_builder *b, struct vtn_type *type,
                       enum vtn_variable_mode mode)
@@ -839,6 +866,13 @@ vtn_type_get_nir_type(struct vtn_builder *b, struct vtn_type *type,
       }
    }
 
+   /* Layout decorations are allowed but ignored in certain conditions,
+    * to allow SPIR-V generators perform type deduplication.  Discard
+    * unnecessary ones when passing to NIR.
+    */
+   if (!vtn_type_needs_explicit_layout(b, mode))
+      return glsl_get_bare_type(type->type);
+
    return type->type;
 }
 

src/compiler/spirv/vtn_variables.c

@@ -2197,10 +2197,6 @@ vtn_create_variable(struct vtn_builder *b, struct vtn_value *val,
       /* Create the variable normally */
       var->var = rzalloc(b->shader, nir_variable);
       var->var->name = ralloc_strdup(var->var, val->name);
-      /* Workgroup variables don't have any explicit layout but some
-       * layouts may have leaked through due to type deduplication in the
-       * SPIR-V.
-       */
       var->var->type = vtn_type_get_nir_type(b, var->type, var->mode);
       var->var->data.mode = nir_var_mem_shared;
       break;
@@ -2253,11 +2249,6 @@ vtn_create_variable(struct vtn_builder *b, struct vtn_value *val,
 
       var->var = rzalloc(b->shader, nir_variable);
       var->var->name = ralloc_strdup(var->var, val->name);
-      /* In Vulkan, shader I/O variables don't have any explicit layout but
-       * some layouts may have leaked through due to type deduplication in
-       * the SPIR-V.  We do, however, keep the layouts in the variable's
-       * interface_type because we need offsets for XFB arrays of blocks.
-       */
       var->var->type = vtn_type_get_nir_type(b, var->type, var->mode);
       var->var->data.mode = nir_mode;
       var->var->data.patch = var->patch;