glsl: add varying resources for arrays of complex types

Fixes some parts of

KHR-GL45.enhanced_layouts.varying_structure_locations

TODO: fix locations for TCS/TES/GS arrayed things

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/compiler/glsl/linker.cpp

@@ -3870,7 +3870,41 @@ add_shader_variable(const struct gl_context *ctx,
       }
       return true;
    }
-
+   case GLSL_TYPE_ARRAY: {
+      /* The ARB_program_interface_query spec says:
+       *
+       *     "For an active variable declared as an array of basic types, a
+       *      single entry will be generated, with its name string formed by
+       *      concatenating the name of the array and the string "[0]"."
+       *
+       *     "For an active variable declared as an array of an aggregate data
+       *      type (structures or arrays), a separate entry will be generated
+       *      for each active array element, unless noted immediately below.
+       *      The name of each entry is formed by concatenating the name of
+       *      the array, the "[" character, an integer identifying the element
+       *      number, and the "]" character.  These enumeration rules are
+       *      applied recursively, treating each enumerated array element as a
+       *      separate active variable."
+       */
+      const struct glsl_type *array_type = type->fields.array;
+      if (array_type->base_type == GLSL_TYPE_STRUCT ||
+          array_type->base_type == GLSL_TYPE_ARRAY) {
+         unsigned elem_location = location;
+         unsigned stride = array_type->count_attribute_slots(false);
+         for (unsigned i = 0; i < type->length; i++) {
+            char *elem = ralloc_asprintf(shProg, "%s[%d]", name, i);
+            if (!add_shader_variable(ctx, shProg, resource_set,
+                                     stage_mask, programInterface,
+                                     var, elem, array_type,
+                                     use_implicit_location, elem_location,
+                                     outermost_struct_type))
+               return false;
+            elem_location += stride;
+         }
+         return true;
+      }
+      /* fallthrough */
+   }
    default: {
       /* The ARB_program_interface_query spec says:
        *