[Feature #18901] Support size pool movement for Arrays

This commit enables Arrays to move between size pools during compaction.
This can occur if the array is mutated such that it would fit in a
different size pool when embedded.

The move is carried out in two stages:

1. The RVALUE is moved to a destination heap during object movement
   phase of compaction
2. The array data is re-embedded and the original buffer free'd if
   required. This happens during the update references step

1 files changed, 18 insertions, 7 deletions

diff --git a/gc.c b/gc.c
index 4741cb7b04..39d82a6a77 100644
--- a/gc.c
+++ b/gc.c
@@ -8324,16 +8324,20 @@ gc_compact_destination_pool(rb_objspace_t *objspace, rb_size_pool_t *src_pool, V
     switch (BUILTIN_TYPE(src)) {
         case T_STRING:
             obj_size = rb_str_size_as_embedded(src);
-            if (rb_gc_size_allocatable_p(obj_size)){
-                return &size_pools[size_pool_idx_for_size(obj_size)];
-            }
-            else {
-                GC_ASSERT(!STR_EMBED_P(src));
-                return &size_pools[0];
-            }
+            break;
+        case T_ARRAY:
+            obj_size = rb_ary_size_as_embedded(src);
+            break;
         default:
             return src_pool;
     }
+
+    if (rb_gc_size_allocatable_p(obj_size)) {
+        return &size_pools[size_pool_idx_for_size(obj_size)];
+    }
+    else {
+        return &size_pools[0];
+    }
 }
 
 static bool
@@ -10368,6 +10372,13 @@ gc_update_object_references(rb_objspace_t *objspace, VALUE obj)
         else {
             gc_ref_update_array(objspace, obj);
         }
+#if USE_RVARGC
+        if ((size_t)GET_HEAP_PAGE(obj)->slot_size >= rb_ary_size_as_embedded(obj)) {
+            if (rb_ary_embeddable_p(obj)) {
+                rb_ary_make_embedded(obj);
+            }
+        }
+#endif
         break;
 
       case T_HASH: