WIP

Author: byroot

gc.c

@@ -1937,20 +1937,33 @@ object_id_get(VALUE obj, shape_id_t shape_id)
         else {
             id = rb_obj_field_get(obj, rb_shape_object_id_inline(shape_id));
         }
+
+#if RUBY_DEBUG
+    if (!(FIXNUM_P(id) || RB_TYPE_P(id, T_BIGNUM))) {
+        rb_p(obj);
+        rb_bug("Object's shape includes object_id, but it's missing %s", rb_obj_info(obj));
+    }
+#endif
+
         break;
       case SHAPE_EXTERNAL_OBJ_ID:
-        RUBY_ASSERT(obj_to_id_tbl);
-        st_lookup(obj_to_id_tbl, obj, &id);
-        break;
-    }
+        {
+            RUBY_ASSERT(obj_to_id_tbl);
+            unsigned int lock_lev = RB_GC_VM_LOCK();
+            st_lookup(obj_to_id_tbl, obj, &id);
 
 #if RUBY_DEBUG
     if (!(FIXNUM_P(id) || RB_TYPE_P(id, T_BIGNUM))) {
         rb_p(obj);
-        rb_bug("Object's shape includes object_id, but it's missing %s", rb_obj_info(obj));
+        rb_bug("Object's shape includes external object_id, but it's missing in obj_to_id_tbl %s", rb_obj_info(obj));
     }
 #endif
 
+            RB_GC_VM_UNLOCK(lock_lev);
+        }
+        break;
+    }
+
     return id;
 }
 
@@ -1968,9 +1981,9 @@ object_id0(VALUE obj, bool shareable)
 
     attr_index_t capacity = RSHAPE_CAPACITY(shape_id);
     attr_index_t free_capacity = capacity - RSHAPE_LEN(shape_id);
-    if (shareable && capacity && !free_capacity) {
-        // The object is shared and has no free capacity, we can't
-        // safely store the object_id inline.
+    if (shareable && RB_TYPE_P(obj, T_OBJECT) && capacity && !free_capacity) {
+        // If the object was shared and has no free capacity, we can't safely store the object_id inline.
+        // This is only a problem for T_OBJECT, given other types have external fields and can do RCU.
         shape_id_t next_shape_id = rb_shape_transition_object_id_external(obj);
         if (RB_UNLIKELY(!obj_to_id_tbl)) {
             obj_to_id_tbl = st_init_numtable();
@@ -4097,6 +4110,30 @@ vm_weak_table_id2ref_foreach_update(st_data_t *key, st_data_t *value, st_data_t
     return ST_CONTINUE;
 }
 
+static int
+vm_weak_table_obj2id_foreach(st_data_t key, st_data_t value, st_data_t data, int error)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    if (!iter_data->weak_only && !FIXNUM_P((VALUE)value)) {
+        iter_data->callback((VALUE)value, iter_data->data);
+    }
+
+    return iter_data->callback((VALUE)key, iter_data->data);
+}
+
+static int
+vm_weak_table_obj2id_foreach_update(st_data_t *key, st_data_t *value, st_data_t data, int existing)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    if (!iter_data->weak_only && !FIXNUM_P((VALUE)*value)) {
+        iter_data->update_callback((VALUE *)value, iter_data->data);
+    }
+
+    return iter_data->update_callback((VALUE *)key, iter_data->data);
+}
+
 static int
 vm_weak_table_gen_fields_foreach(st_data_t key, st_data_t value, st_data_t data)
 {
@@ -4240,8 +4277,8 @@ rb_gc_vm_weak_table_foreach(vm_table_foreach_callback_func callback,
         if (obj_to_id_tbl) {
             st_foreach_with_replace(
                 obj_to_id_tbl,
-                vm_weak_table_foreach_weak_key,
-                vm_weak_table_foreach_update_weak_key,
+                vm_weak_table_obj2id_foreach,
+                vm_weak_table_obj2id_foreach_update,
                 (st_data_t)&foreach_data
             );
         }

gc/default/default.c

@@ -7048,6 +7048,10 @@ gc_ref_update(void *vstart, void *vend, size_t stride, rb_objspace_t *objspace,
 static int
 gc_update_references_weak_table_i(VALUE obj, void *data)
 {
+    if (SPECIAL_CONST_P(obj)) {
+        return ST_CONTINUE;
+    }
+
     int ret;
     asan_unpoisoning_object(obj) {
         ret = BUILTIN_TYPE(obj) == T_MOVED ? ST_REPLACE : ST_CONTINUE;