nir_types: add glsl_type_is_leaf helper

Helper used to know when a glsl_type is a leaf when iteraring through
a complex type. Note that GLSL IR linking also uses the concept of
leaf while doing the same iteration, although in that case it uses a
visitor. See link_uniform_blocks, process_array_leaf and others as
reference.

Signed-off-by: Alejandro Piñeiro <apinheiro@igalia.com>
Signed-off-by: Antia Puentes <apuentes@igalia.com>

v2:
   * Moved from gl_nir_linker to nir_types, so it could be used on nir
     xfb gathering (Timothy Arceri)
   * Minor update after Timothy's series about record to struct
     renaming landed master.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/compiler/nir_types.cpp

@@ -727,3 +727,16 @@ glsl_get_explicit_size(const struct glsl_type *type, bool align_to_stride)
 {
    return type->explicit_size(align_to_stride);
 }
+
+bool
+glsl_type_is_leaf(const struct glsl_type *type)
+{
+   if (glsl_type_is_struct_or_ifc(type) ||
+       (glsl_type_is_array(type) &&
+        (glsl_type_is_array(glsl_get_array_element(type)) ||
+         glsl_type_is_struct_or_ifc(glsl_get_array_element(type))))) {
+      return false;
+   } else {
+      return true;
+   }
+}

src/compiler/nir_types.h

@@ -202,6 +202,8 @@ const struct glsl_type *glsl_atomic_uint_type(void);
 unsigned glsl_type_get_sampler_count(const struct glsl_type *type);
 unsigned glsl_type_get_image_count(const struct glsl_type *type);
 
+bool glsl_type_is_leaf(const struct glsl_type *type);
+
 #ifdef __cplusplus
 }
 #endif