fix rb_obj_copy_ivar to not copy object_id over

Author: byroot

object.c

@@ -329,54 +329,72 @@ rb_obj_copy_ivar(VALUE dest, VALUE obj)
     RUBY_ASSERT(!RB_TYPE_P(obj, T_CLASS) && !RB_TYPE_P(obj, T_MODULE));
 
     RUBY_ASSERT(BUILTIN_TYPE(dest) == BUILTIN_TYPE(obj));
+
+    unsigned long src_num_ivs = rb_ivar_count(obj);
+    if (!src_num_ivs) {
+        return;
+    }
+
     rb_shape_t *src_shape = rb_shape_get_shape(obj);
 
-    if (rb_shape_obj_too_complex(obj)) {
+    if (rb_shape_too_complex_p(src_shape)) {
         // obj is TOO_COMPLEX so we can copy its iv_hash
         st_table *table = st_copy(ROBJECT_IV_HASH(obj));
+        if (rb_shape_has_object_id(src_shape)) {
+            st_data_t id = (st_data_t)internal_object_id;
+            st_delete(table, &id, NULL);
+        }
         rb_obj_init_too_complex(dest, table);
 
         return;
     }
 
-    uint32_t src_num_ivs = RBASIC_FIELDS_COUNT(obj);
     rb_shape_t *shape_to_set_on_dest = src_shape;
-    VALUE * src_buf;
-    VALUE * dest_buf;
-
-    if (!src_num_ivs) {
-        return;
-    }
-
-    src_buf = ROBJECT_IVPTR(obj);
-    dest_buf = ROBJECT_IVPTR(dest);
-
     rb_shape_t *initial_shape = rb_shape_get_shape(dest);
 
     if (initial_shape->heap_index != src_shape->heap_index || !rb_shape_canonical_p(src_shape)) {
         RUBY_ASSERT(initial_shape->type == SHAPE_T_OBJECT);
 
         shape_to_set_on_dest = rb_shape_rebuild_shape(initial_shape, src_shape);
         if (UNLIKELY(rb_shape_too_complex_p(shape_to_set_on_dest))) {
-            st_table * table = rb_st_init_numtable_with_size(src_num_ivs);
+            st_table *table = rb_st_init_numtable_with_size(src_num_ivs);
             rb_obj_copy_ivs_to_hash_table(obj, table);
             rb_obj_init_too_complex(dest, table);
 
             return;
         }
     }
 
-    RUBY_ASSERT(src_num_ivs <= shape_to_set_on_dest->capacity || rb_shape_too_complex_p(shape_to_set_on_dest));
+    VALUE *src_buf = ROBJECT_IVPTR(obj);
+    VALUE *dest_buf = ROBJECT_IVPTR(dest);
+
+    RUBY_ASSERT(src_num_ivs <= shape_to_set_on_dest->capacity);
     if (initial_shape->capacity < shape_to_set_on_dest->capacity) {
         rb_ensure_iv_list_size(dest, initial_shape->capacity, shape_to_set_on_dest->capacity);
         dest_buf = ROBJECT_IVPTR(dest);
     }
 
-    MEMCPY(dest_buf, src_buf, VALUE, src_num_ivs);
+    if (src_shape->next_field_index == shape_to_set_on_dest->next_field_index) {
+        // Happy path, we can just memcpy the ivptr content
+        MEMCPY(dest_buf, src_buf, VALUE, src_num_ivs);
+
+        // Fire write barriers
+        for (uint32_t i = 0; i < src_num_ivs; i++) {
+            RB_OBJ_WRITTEN(dest, Qundef, dest_buf[i]);
+        }
+    }
+    else {
+        rb_shape_t *dest_shape = shape_to_set_on_dest;
+        while (src_shape->parent_id != INVALID_SHAPE_ID) {
+            if (src_shape->type == SHAPE_IVAR) {
+                while (dest_shape->edge_name != src_shape->edge_name) {
+                    dest_shape = rb_shape_get_shape_by_id(dest_shape->parent_id);
+                }
 
-    // Fire write barriers
-    for (uint32_t i = 0; i < src_num_ivs; i++) {
-        RB_OBJ_WRITTEN(dest, Qundef, dest_buf[i]);
+                RB_OBJ_WRITE(dest, &dest_buf[dest_shape->next_field_index - 1], src_buf[src_shape->next_field_index - 1]);
+            }
+            src_shape = rb_shape_get_shape_by_id(src_shape->parent_id);
+        }
     }
 
     rb_shape_set_shape(dest, shape_to_set_on_dest);