glsl: add helper for calculating size of AoA

V2: return 0 if not array rather than -1

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/glsl/glsl_types.h

@@ -577,6 +577,25 @@ struct glsl_type {
       return t;
    }
 
+   /**
+    * Return the total number of elements in an array including the elements
+    * in arrays of arrays.
+    */
+   unsigned arrays_of_arrays_size() const
+   {
+      if (!is_array())
+         return 0;
+
+      unsigned size = length;
+      const glsl_type *base_type = fields.array;
+
+      while (base_type->is_array()) {
+         size = size * base_type->length;
+         base_type = base_type->fields.array;
+      }
+      return size;
+   }
+
    /**
     * Return the amount of atomic counter storage required for a type.
     */