Do not mark the unused items of a WeakMap (#4663)

The new method is slower, but correctly release unused objects.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/ecma/base/ecma-gc.c

@@ -327,6 +327,46 @@ ecma_gc_mark_properties (ecma_object_t *object_p, /**< object */
           break;
         }
 #endif /* JERRY_ESNEXT */
+#if JERRY_BUILTIN_WEAKMAP
+        case LIT_INTERNAL_MAGIC_STRING_WEAK_REFS:
+        {
+          ecma_value_t key_arg = ecma_make_object_value (object_p);
+          ecma_collection_t *refs_p;
+
+          refs_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_collection_t, property_pair_p->values[index].value);
+
+          for (uint32_t j = 0; j < refs_p->item_count; j++)
+          {
+            const ecma_value_t reference_value = refs_p->buffer_p[j];
+
+            if (ecma_is_value_empty (reference_value))
+            {
+              continue;
+            }
+
+            ecma_object_t *reference_object_p = ecma_get_object_from_value (reference_value);
+
+            JERRY_ASSERT (ecma_get_object_type (reference_object_p) == ECMA_OBJECT_TYPE_CLASS);
+
+            ecma_extended_object_t *map_object_p = (ecma_extended_object_t *) reference_object_p;
+
+            if (map_object_p->u.cls.type != ECMA_OBJECT_CLASS_CONTAINER
+                || map_object_p->u.cls.u2.container_id != LIT_MAGIC_STRING_WEAKMAP_UL
+                || !ecma_gc_is_object_visited (reference_object_p))
+            {
+              continue;
+            }
+
+            ecma_value_t value = ecma_op_container_find_weak_value (reference_object_p, key_arg);
+
+            if (ecma_is_value_object (value))
+            {
+              ecma_gc_set_object_visited (ecma_get_object_from_value (value));
+            }
+          }
+          break;
+        }
+#endif /* JERRY_BUILTIN_WEAKMAP */
         case LIT_INTERNAL_MAGIC_STRING_NATIVE_POINTER_WITH_REFERENCES:
         {
           jerry_value_t value = property_pair_p->values[index].value;
@@ -526,7 +566,10 @@ ecma_gc_mark_weakmap_object (ecma_object_t *object_p) /**< object */
       continue;
     }
 
-    if (ecma_is_value_object (entry_p->value))
+    JERRY_ASSERT (ecma_is_value_object (entry_p->key));
+
+    if (ecma_is_value_object (entry_p->value)
+        && ecma_gc_is_object_visited (ecma_get_object_from_value (entry_p->key)))
     {
       ecma_gc_set_object_visited (ecma_get_object_from_value (entry_p->value));
     }

jerry-core/ecma/operations/ecma-container-object.c

@@ -870,6 +870,30 @@ ecma_op_container_delete_weak (ecma_extended_object_t *map_object_p, /**< map ob
   return ECMA_VALUE_TRUE;
 } /* ecma_op_container_delete_weak */
 
+/**
+ * Helper function to get the value from a weak container object
+ *
+ * @return value property
+ */
+ecma_value_t
+ecma_op_container_find_weak_value (ecma_object_t *object_p, /**< internal container object */
+                                   ecma_value_t key_arg) /**< key */
+{
+  ecma_extended_object_t *map_object_p = (ecma_extended_object_t *) object_p;
+
+  JERRY_ASSERT (map_object_p->u.cls.type == ECMA_OBJECT_CLASS_CONTAINER
+                && map_object_p->u.cls.u2.container_id == LIT_MAGIC_STRING_WEAKMAP_UL);
+
+  ecma_collection_t *container_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_collection_t,
+                                                                    map_object_p->u.cls.u3.value);
+
+  ecma_value_t *entry_p = ecma_op_internal_buffer_find (container_p, key_arg, map_object_p->u.cls.u2.container_id);
+
+  JERRY_ASSERT (entry_p != NULL);
+
+  return entry_p[1];
+} /* ecma_op_container_find_weak_value */
+
 /**
  * Helper function to remove a key/value pair from a weak container object
  */
@@ -879,6 +903,10 @@ ecma_op_container_remove_weak_entry (ecma_object_t *object_p, /**< internal cont
 {
   ecma_extended_object_t *map_object_p = (ecma_extended_object_t *) object_p;
 
+  JERRY_ASSERT (map_object_p->u.cls.type == ECMA_OBJECT_CLASS_CONTAINER
+                && (map_object_p->u.cls.u2.container_id == LIT_MAGIC_STRING_WEAKSET_UL
+                    || map_object_p->u.cls.u2.container_id == LIT_MAGIC_STRING_WEAKMAP_UL));
+
   ecma_collection_t *container_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_collection_t,
                                                                     map_object_p->u.cls.u3.value);
 

jerry-core/ecma/operations/ecma-container-object.h

@@ -67,7 +67,8 @@ ecma_value_t ecma_op_container_delete (ecma_extended_object_t *map_object_p, ecm
                                        lit_magic_string_id_t lit_id);
 ecma_value_t ecma_op_container_delete_weak (ecma_extended_object_t *map_object_p, ecma_value_t key_arg,
                                             lit_magic_string_id_t lit_id);
-void ecma_op_container_remove_weak_entry (ecma_object_t *container_p, ecma_value_t key_arg);
+ecma_value_t ecma_op_container_find_weak_value (ecma_object_t *object_p, ecma_value_t key_arg);
+void ecma_op_container_remove_weak_entry (ecma_object_t *object_p, ecma_value_t key_arg);
 void ecma_op_container_free_entries (ecma_object_t *object_p);
 ecma_value_t ecma_op_container_create_iterator (ecma_value_t this_arg,
                                                 ecma_builtin_id_t proto_id,

jerry-core/ecma/operations/ecma-objects.c

@@ -3419,10 +3419,10 @@ ecma_op_object_set_weak (ecma_object_t *object_p, /**< key object */
 
   if (property_p == NULL)
   {
+    refs_p = ecma_new_collection ();
+
     ecma_property_value_t *value_p;
     ECMA_CREATE_INTERNAL_PROPERTY (object_p, weak_refs_string_p, property_p, value_p);
-
-    refs_p = ecma_new_collection ();
     ECMA_SET_INTERNAL_VALUE_POINTER (value_p->value, refs_p);
   }
   else

tests/unit-core/test-container.c

@@ -16,6 +16,24 @@
 #include "jerryscript.h"
 #include "test-common.h"
 
+static int global_counter;
+
+static void
+native_free_callback (void *native_p, /**< native pointer */
+                      jerry_object_native_info_t *info_p) /**< native info */
+{
+  TEST_ASSERT (native_p == (void *) &global_counter);
+  TEST_ASSERT (info_p->free_cb == native_free_callback);
+  global_counter++;
+} /* native_free_callback */
+
+static const jerry_object_native_info_t native_info =
+{
+  .free_cb = native_free_callback,
+  .number_of_references = 0,
+  .offset_of_references = 0,
+};
+
 int
 main (void)
 {
@@ -81,6 +99,29 @@ main (void)
   jerry_release_value (global_weakset);
   jerry_release_value (empty_weakset);
 
+  const jerry_char_t source[] = TEST_STRING_LITERAL (
+    "(function () {\n"
+    "  var o1 = {}\n"
+    "  var o2 = {}\n"
+    "  var o3 = {}\n"
+    "  var wm = new WeakMap()\n"
+    "  wm.set(o1, o2)\n"
+    "  wm.set(o2, o3)\n"
+    "  return o3\n"
+    "})()\n"
+  );
+  jerry_value_t result = jerry_eval (source,
+                                     sizeof (source) - 1,
+                                     JERRY_PARSE_NO_OPTS);
+  TEST_ASSERT (jerry_value_is_object (result));
+
+  jerry_set_object_native_pointer (result, (void *) &global_counter, &native_info);
+  jerry_release_value (result);
+
+  global_counter = 0;
+  jerry_gc (JERRY_GC_PRESSURE_LOW);
+  TEST_ASSERT (global_counter == 1);
+
   jerry_cleanup ();
   return 0;
 } /* main */