More precisely iterate over Object instance variables

Shapes provides us with an (almost) exact count of instance variables.
We only need to check for Qundef when an IV has been "undefined"
Prefer to use ROBJECT_IV_COUNT when iterating IVs

1 files changed, 9 insertions, 0 deletions

diff --git a/shape.h b/shape.h
index c99fd1bfaa..e978bac121 100644
--- a/shape.h
+++ b/shape.h
@@ -125,6 +125,15 @@ bool rb_shape_get_iv_index(rb_shape_t * shape, ID id, attr_index_t * value);
 shape_id_t rb_shape_id(rb_shape_t * shape);
 MJIT_SYMBOL_EXPORT_END
 
+static inline uint32_t
+ROBJECT_IV_COUNT(VALUE obj)
+{
+    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
+    uint32_t ivc = rb_shape_get_shape_by_id(ROBJECT_SHAPE_ID(obj))->iv_count;
+    RUBY_ASSERT(ivc <= ROBJECT_NUMIV(obj));
+    return ivc;
+}
+
 rb_shape_t * rb_shape_alloc(ID edge_name, rb_shape_t * parent);
 rb_shape_t * rb_shape_alloc_with_parent_id(ID edge_name, shape_id_t parent_id);