Fix Object Movement allocation in GC

When moving Objects between size pools we have to assign a new shape.

This happened during updating references - we tried to create a new shape
tree that mirrored the existing tree, but based on the root shape of the
new size pool.

This causes allocations to happen if the new tree doesn't already exist,
potentially triggering a GC, during GC.

This commit changes object movement to look for a pre-existing new tree
during object movement, and if that tree does not exist, we don't move
the object to the new pool.

This allows us to remove the shape allocation from update references.

Co-Authored-By: Peter Zhu <peter@peterzhu.ca>

1 files changed, 2 insertions, 0 deletions

diff --git a/shape.h b/shape.h
index ddb870f5e7..9a7d31c369 100644
--- a/shape.h
+++ b/shape.h
@@ -178,6 +178,8 @@ rb_shape_t * rb_shape_alloc(ID edge_name, rb_shape_t * parent);
 rb_shape_t * rb_shape_alloc_with_size_pool_index(ID edge_name, rb_shape_t * parent, uint8_t size_pool_index);
 rb_shape_t * rb_shape_alloc_with_parent_id(ID edge_name, shape_id_t parent_id);
 
+rb_shape_t *rb_shape_traverse_from_new_root(rb_shape_t *initial_shape, rb_shape_t *orig_shape);
+
 bool rb_shape_set_shape_id(VALUE obj, shape_id_t shape_id);
 
 VALUE rb_obj_debug_shape(VALUE self, VALUE obj);