Implement ECMAScript 2022 private class methods and fields (#4831)

Co-authored-by: Robert Fancsik robert.fancsik@h-lab.eu
Co-authored-by: Martin Negyokru mnegyokru@inf.u-szeged.hu
JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

Author: szilagyiadam

jerry-core/ecma/base/ecma-error-messages.inc.h

@@ -298,6 +298,9 @@ ECMA_ERROR_DEF (ECMA_ERR_MODULE_MUST_BE_IN_LINKED_STATE, "Module must be in link
 ECMA_ERROR_DEF (ECMA_ERR_UNKNOWN_EXPORT, "Native module export not found")
 #endif /* JERRY_MODULE_SYSTEM */
 ECMA_ERROR_DEF (ECMA_ERR_PASSED_ARGUMENT_IS_NOT_A_REALM, "Passed argument is not a realm")
+#if JERRY_ESNEXT
+ECMA_ERROR_DEF (ECMA_ERR_PRIVATE_METHOD_IS_NOT_WRITABLE, "Private method is not writable")
+#endif /* JERRY_ESNEXT */
 #if JERRY_BUILTIN_BIGINT || JERRY_BUILTIN_NUMBER
 ECMA_ERROR_DEF (ECMA_ERR_RADIX_IS_OUT_OF_RANGE, "Radix must be between 2 and 36")
 #endif /* JERRY_BUILTIN_BIGINT \
@@ -548,6 +551,9 @@ ECMA_ERROR_DEF (ECMA_ERR_VALUE_RECEIVED_BY_YIELD_IS_NOT_OBJECT, "Value received
 #if JERRY_BUILTIN_BOOLEAN
 ECMA_ERROR_DEF (ECMA_ERR_ARGUMENT_THIS_NOT_BOOLEAN_OBJECT, "Argument 'this' is not a Boolean object")
 #endif /* JERRY_BUILTIN_BOOLEAN */
+#if JERRY_ESNEXT
+ECMA_ERROR_DEF (ECMA_ERR_CANNOT_DECLARE_SAME_PRIVATE_FIELD_TWICE, "Cannot declare same private field twice")
+#endif /* JERRY_ESNEXT */
 #if JERRY_BUILTIN_TYPEDARRAY
 ECMA_ERROR_DEF (ECMA_ERR_CONSTRUCTOR_FLOAT32_ARRAY_REQUIRES_NEW, "Constructor Float32Array requires 'new'")
 #endif /* JERRY_BUILTIN_TYPEDARRAY */
@@ -608,6 +614,8 @@ ECMA_ERROR_DEF (ECMA_ERR_CANNOT_CONVERT_TO_OBJECT, "Cannot convert undefined or
 ECMA_ERROR_DEF (ECMA_ERR_PRECISION_DIGITS_MUST_BE_BETWEEN_IN_RANGE, "Precision digits must be between 1 and 100")
 #endif /* JERRY_BUILTIN_NUMBER */
 #if JERRY_ESNEXT
+ECMA_ERROR_DEF (ECMA_ERR_PRIVATE_FIELD_WAS_DEFINED_WITHOUT_A_GETTER, "Private field was defined without a getter")
+ECMA_ERROR_DEF (ECMA_ERR_PRIVATE_FIELD_WAS_DEFINED_WITHOUT_A_SETTER, "Private field was defined without a setter")
 ECMA_ERROR_DEF (ECMA_ERR_PROPERTY_NAME_IS_NEITHER_SYMBOL_NOR_STRING, "Property name is neither Symbol nor string")
 #endif /* JERRY_ESNEXT */
 #if JERRY_BUILTIN_BIGINT
@@ -818,8 +826,20 @@ ECMA_ERROR_DEF (ECMA_ERR_TARGET_NOT_EXTENSIBLE_DIFFERENT_PROTOTYPE_RETURNED,
                 "Target object is non-extensible and trap returned different prototype")
 ECMA_ERROR_DEF (ECMA_ERR_TRAP_TRUISH_ADDING_PROPERTY_NON_EXTENSIBLE_TARGET,
                 "Trap returned truish for adding property to the non-extensible target")
+#endif /* JERRY_BUILTIN_PROXY */
+#if JERRY_ESNEXT
+ECMA_ERROR_DEF (ECMA_ERR_CANNOT_READ_PRIVATE_MEMBER_TO_AN_OBJECT_WHOSE_CLASS_DID_NOT_DECLARE_IT,
+                "Cannot read private member to an object whose class did not declare it")
+#endif /* JERRY_ESNEXT */
+#if JERRY_BUILTIN_PROXY
 ECMA_ERROR_DEF (ECMA_ERR_GIVEN_PROPERTY_IS_A_NON_CONFIGURABLE,
                 "Given property is a non-configurable data property on the proxy target")
+#endif /* JERRY_BUILTIN_PROXY */
+#if JERRY_ESNEXT
+ECMA_ERROR_DEF (ECMA_ERR_CANNOT_WRITE_PRIVATE_MEMBER_TO_AN_OBJECT_WHOSE_CLASS_DID_NOT_DECLARE_IT,
+                "Cannot write private member to an object whose class did not declare it")
+#endif /* JERRY_ESNEXT */
+#if JERRY_BUILTIN_PROXY
 ECMA_ERROR_DEF (ECMA_ERR_TRAP_FALSISH_PROPERTY_TARGET_NOT_EXTENSIBLE,
                 "Trap returned falsish for property but the proxy target is not extensible")
 ECMA_ERROR_DEF (ECMA_ERR_PROXY_PROPERTY_NOT_CONFIGURABLE_NOT_HAVE_GETTER,

jerry-core/ecma/base/ecma-error-messages.ini

@@ -323,4 +323,10 @@ ECMA_ERR_PROXY_TARGET_IS_NOT_A_CONSTRUCTOR = "Proxy target is not a constructor"
 ECMA_ERR_MAXIMUM_CALL_STACK_SIZE_EXCEEDED = "Maximum call stack size exceeded"
 ECMA_ERR_INVALID_SNAPSHOT_FORMAT = "Invalid snapshot format"
 ECMA_ERR_INVALID_SNAPSHOT_VERSION_OR_FEATURES = "Invalid snapshot version or unsupported features present"
-ECMA_ERR_RECEIVER_MUST_BE_AN_OBJECT = "Receiver must be an object"
+ECMA_ERR_RECEIVER_MUST_BE_AN_OBJECT = "Receiver must be an object"
+ECMA_ERR_CANNOT_DECLARE_SAME_PRIVATE_FIELD_TWICE = "Cannot declare same private field twice"
+ECMA_ERR_CANNOT_WRITE_PRIVATE_MEMBER_TO_AN_OBJECT_WHOSE_CLASS_DID_NOT_DECLARE_IT = "Cannot write private member to an object whose class did not declare it"
+ECMA_ERR_PRIVATE_METHOD_IS_NOT_WRITABLE = "Private method is not writable"
+ECMA_ERR_PRIVATE_FIELD_WAS_DEFINED_WITHOUT_A_SETTER = "Private field was defined without a setter"
+ECMA_ERR_CANNOT_READ_PRIVATE_MEMBER_TO_AN_OBJECT_WHOSE_CLASS_DID_NOT_DECLARE_IT = "Cannot read private member to an object whose class did not declare it"
+ECMA_ERR_PRIVATE_FIELD_WAS_DEFINED_WITHOUT_A_GETTER = "Private field was defined without a getter"

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

@@ -328,6 +328,27 @@ ecma_gc_mark_properties (ecma_object_t *object_p, /**< object */
           ecma_gc_set_object_visited (ecma_get_object_from_value (environment_record_p->function_object));
           break;
         }
+        case LIT_INTERNAL_MAGIC_STRING_CLASS_PRIVATE_ELEMENTS:
+        {
+          ecma_value_t *compact_collection_p;
+          compact_collection_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_value_t, property_pair_p->values[index].value);
+
+          ecma_value_t *end_p = ecma_compact_collection_end (compact_collection_p);
+          ecma_value_t *current_p = compact_collection_p + 1;
+
+          while (end_p - current_p >= ECMA_PRIVATE_ELEMENT_LIST_SIZE)
+          {
+            current_p++; /* skip the type */
+            current_p++; /* skip the name */
+            ecma_value_t value = *current_p++;
+
+            if (!ecma_is_value_undefined (value))
+            {
+              ecma_gc_set_object_visited (ecma_get_object_from_value (value));
+            }
+          }
+          break;
+        }
 #endif /* JERRY_ESNEXT */
 #if JERRY_BUILTIN_CONTAINER
         case LIT_INTERNAL_MAGIC_STRING_WEAK_REFS:
@@ -816,8 +837,12 @@ ecma_gc_mark (ecma_object_t *object_p) /**< object to mark from */
 #if JERRY_MODULE_SYSTEM
         if (object_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA)
         {
-          ecma_gc_mark_properties (object_p, true);
-          ecma_gc_set_object_visited (((ecma_lexical_environment_class_t *) object_p)->module_p);
+          if (ECMA_LEX_ENV_CLASS_IS_MODULE (object_p))
+          {
+            ecma_gc_mark_properties (object_p, true);
+          }
+
+          ecma_gc_set_object_visited (((ecma_lexical_environment_class_t *) object_p)->object_p);
           return;
         }
 #endif /* JERRY_MODULE_SYSTEM */
@@ -1591,6 +1616,26 @@ ecma_gc_free_property (ecma_object_t *object_p, /**< object */
       ecma_compact_collection_free (compact_collection_p);
       break;
     }
+    case LIT_INTERNAL_MAGIC_STRING_CLASS_PRIVATE_ELEMENTS:
+    {
+      ecma_value_t *compact_collection_p;
+      compact_collection_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_value_t, value);
+
+      ecma_value_t *end_p = ecma_compact_collection_end (compact_collection_p);
+      ecma_value_t *current_p = compact_collection_p + 1;
+
+      JERRY_ASSERT ((end_p - current_p) % ECMA_PRIVATE_ELEMENT_LIST_SIZE == 0);
+
+      while (current_p < end_p)
+      {
+        current_p++; /* skip the type */
+        ecma_deref_ecma_string (ecma_get_prop_name_from_value (*current_p++));
+        current_p++; /* skip the value */
+      }
+
+      ecma_compact_collection_destroy (compact_collection_p);
+      break;
+    }
 #endif /* JERRY_ESNEXT */
 #if JERRY_BUILTIN_WEAKREF || JERRY_BUILTIN_CONTAINER
     case LIT_INTERNAL_MAGIC_STRING_WEAK_REFS:
@@ -1684,7 +1729,11 @@ ecma_gc_free_object (ecma_object_t *object_p) /**< object to free */
     if (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_CLASS
         && (object_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA))
     {
-      ecma_gc_free_properties (object_p, ECMA_GC_FREE_REFERENCES);
+      if (ECMA_LEX_ENV_CLASS_IS_MODULE (object_p))
+      {
+        ecma_gc_free_properties (object_p, ECMA_GC_FREE_REFERENCES);
+      }
+
       ecma_dealloc_extended_object (object_p, sizeof (ecma_lexical_environment_class_t));
       return;
     }

jerry-core/ecma/base/ecma-globals.h

@@ -1184,16 +1184,32 @@ typedef struct
   ecma_built_in_props_t built_in; /**< built-in object part */
 } ecma_extended_built_in_object_t;
 
+/**
+ * Type of lexical environment with class
+ */
+typedef enum
+{
+  ECMA_LEX_ENV_CLASS_TYPE_MODULE, /**< module object reference */
+  ECMA_LEX_ENV_CLASS_TYPE_CLASS_ENV, /**< class constructor object reference */
+} ecma_lexical_environment_class_type_t;
+
 /**
  * Description of lexical environment with class
  */
 typedef struct
 {
   ecma_object_t lexical_env; /**< lexical environment header */
-
-  ecma_object_t *module_p; /**< module reference */
+  uint32_t type; /**< element of ecma_lexical_environment_class_type_t */
+  ecma_object_t *object_p; /**< object reference */
 } ecma_lexical_environment_class_t;
 
+/**
+ * Check whether the given lexical class environment is a module
+ */
+#define ECMA_LEX_ENV_CLASS_IS_MODULE(lex_env_p)                           \
+  (((lex_env_p)->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA) \
+   && ((ecma_lexical_environment_class_t *) (lex_env_p))->type == ECMA_LEX_ENV_CLASS_TYPE_MODULE)
+
 /**
  * Description of native functions
  */
@@ -1892,6 +1908,13 @@ typedef struct
   } u;
 } ecma_extended_string_t;
 
+#if JERRY_ESNEXT
+/**
+ * Required number of ecma values in a compact collection to represent PrivateElement
+ */
+#define ECMA_PRIVATE_ELEMENT_LIST_SIZE 3
+#endif /* JERRY_ESNEXT */
+
 /**
  * String builder header
  */
@@ -2248,24 +2271,23 @@ typedef struct
 } ecma_dataview_object_t;
 #endif /* JERRY_BUILTIN_DATAVIEW */
 
-/**
- * Flag for indicating whether the symbol is a well known symbol
- *
- * See also: 6.1.5.1
- */
-#define ECMA_GLOBAL_SYMBOL_FLAG 0x01
+typedef enum
+{
+  ECMA_SYMBOL_FLAG_NONE = 0, /**< no options */
+  ECMA_SYMBOL_FLAG_GLOBAL = (1 << 0), /**< symbol is a well known symbol, See also: 6.1.5.1 */
+  ECMA_SYMBOL_FLAG_PRIVATE_KEY = (1 << 1), /**< symbol is a private field */
+  ECMA_SYMBOL_FLAG_PRIVATE_INSTANCE_METHOD = (1 << 2), /**< symbol is a private method or accessor */
+} ecma_symbol_flags_t;
 
 /**
- * Bitshift index for indicating whether the symbol is a well known symbol
- *
- * See also: 6.1.5.1
+ * Bitshift index for the symbol hash property
  */
-#define ECMA_GLOBAL_SYMBOL_SHIFT 1
+#define ECMA_SYMBOL_FLAGS_SHIFT 3
 
 /**
- * Bitshift index for the symbol hash property
+ * Bitmask for symbol hash flags
  */
-#define ECMA_SYMBOL_HASH_SHIFT 2
+#define ECMA_SYMBOL_FLAGS_MASK ((1 << ECMA_SYMBOL_FLAGS_SHIFT) - 1)
 
 #if (JERRY_STACK_LIMIT != 0)
 /**
@@ -2481,6 +2503,28 @@ typedef struct
   ecma_extended_object_t header; /**< header part */
   ecma_value_t sync_next_method; /**< IteratorRecord [[NextMethod]] internal slot */
 } ecma_async_from_sync_iterator_object_t;
+
+/**
+ * Private method kind
+ */
+typedef enum
+{
+  ECMA_PRIVATE_FIELD = 0, /**< private field */
+  ECMA_PRIVATE_METHOD, /**< private method */
+  ECMA_PRIVATE_GETTER, /**< private setter */
+  ECMA_PRIVATE_SETTER, /**< private getter */
+} ecma_private_property_kind_t;
+
+/**
+ * Private static property flag
+ */
+#define ECMA_PRIVATE_PROPERTY_STATIC_FLAG (1 << 2)
+
+/*
+ * Get private property kind from a descriptor
+ */
+#define ECMA_PRIVATE_PROPERTY_KIND(prop) ((prop) & ((ECMA_PRIVATE_PROPERTY_STATIC_FLAG - 1)))
+
 #endif /* JERRY_ESNEXT */
 
 /**

jerry-core/ecma/base/ecma-helpers-collection.c

@@ -417,6 +417,31 @@ ecma_compact_collection_free (ecma_value_t *compact_collection_p) /**< compact c
   jmem_heap_free_block (compact_collection_p, size * sizeof (ecma_value_t));
 } /* ecma_compact_collection_free */
 
+/**
+ * Get the end of a compact collection
+ *
+ * @return pointer to the compact collection end
+ */
+ecma_value_t *
+ecma_compact_collection_end (ecma_value_t *compact_collection_p) /**< compact collection */
+{
+  ecma_value_t size = ECMA_COMPACT_COLLECTION_GET_SIZE (compact_collection_p);
+  ecma_value_t unused_items = ECMA_COMPACT_COLLECTION_GET_UNUSED_ITEM_COUNT (compact_collection_p);
+
+  return compact_collection_p + size - unused_items;
+} /* ecma_compact_collection_end */
+
+/**
+ * Destroy a compact collection
+ */
+void
+ecma_compact_collection_destroy (ecma_value_t *compact_collection_p) /**< compact collection */
+{
+  ecma_value_t size = ECMA_COMPACT_COLLECTION_GET_SIZE (compact_collection_p);
+
+  jmem_heap_free_block (compact_collection_p, size * sizeof (ecma_value_t));
+} /* ecma_compact_collection_destroy */
+
 /**
  * @}
  * @}

jerry-core/ecma/base/ecma-helpers-string.c

@@ -221,8 +221,7 @@ ecma_new_symbol_from_descriptor_string (ecma_value_t string_desc) /**< ecma-stri
   ecma_extended_string_t *symbol_p = ecma_alloc_extended_string ();
   symbol_p->header.refs_and_container = ECMA_STRING_REF_ONE | ECMA_STRING_CONTAINER_SYMBOL;
   symbol_p->u.symbol_descriptor = string_desc;
-  symbol_p->header.u.hash = (lit_string_hash_t) (((uintptr_t) symbol_p) >> ECMA_SYMBOL_HASH_SHIFT);
-  JERRY_ASSERT ((symbol_p->header.u.hash & ECMA_GLOBAL_SYMBOL_FLAG) == 0);
+  symbol_p->header.u.hash = (lit_string_hash_t) (((uintptr_t) symbol_p) & (uintptr_t) ~ECMA_SYMBOL_FLAGS_MASK);
 
   return (ecma_string_t *) symbol_p;
 } /* ecma_new_symbol_from_descriptor_string */

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

@@ -306,7 +306,7 @@ ecma_get_lex_env_binding_object (const ecma_object_t *object_p) /**< object-boun
 #if JERRY_ESNEXT
   JERRY_ASSERT (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_THIS_OBJECT_BOUND
                 || (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_CLASS
-                    && (object_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA) == 0));
+                    && !ECMA_LEX_ENV_CLASS_IS_MODULE (object_p)));
 #else /* !JERRY_ESNEXT */
   JERRY_ASSERT (ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_THIS_OBJECT_BOUND);
 #endif /* JERRY_ESNEXT */
@@ -593,7 +593,7 @@ ecma_create_named_reference_property (ecma_object_t *object_p, /**< object */
   JERRY_ASSERT (ecma_find_named_property (object_p, name_p) == NULL);
   JERRY_ASSERT ((ecma_is_lexical_environment (object_p)
                  && ecma_get_lex_env_type (object_p) == ECMA_LEXICAL_ENVIRONMENT_CLASS
-                 && (object_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA))
+                 && ECMA_LEX_ENV_CLASS_IS_MODULE (object_p))
                 || ecma_object_class_is (object_p, ECMA_OBJECT_CLASS_MODULE_NAMESPACE));
 
   uint8_t type_and_flags = ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE;

jerry-core/ecma/base/ecma-helpers.h

@@ -434,6 +434,8 @@ ecma_value_t *ecma_new_compact_collection (void);
 ecma_value_t *ecma_compact_collection_push_back (ecma_value_t *compact_collection_p, ecma_value_t value);
 ecma_value_t *ecma_compact_collection_shrink (ecma_value_t *compact_collection_p);
 void ecma_compact_collection_free (ecma_value_t *compact_collection_p);
+ecma_value_t *ecma_compact_collection_end (ecma_value_t *compact_collection_p);
+void ecma_compact_collection_destroy (ecma_value_t *compact_collection_p);
 
 /* ecma-helpers.c */
 ecma_object_t *ecma_create_object (ecma_object_t *prototype_object_p, size_t ext_object_size, ecma_object_type_t type);

jerry-core/ecma/builtin-objects/ecma-builtins.c

@@ -937,9 +937,9 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
   lit_magic_string_id_t magic_string_id = ecma_get_string_magic (property_name_p);
 
 #if JERRY_ESNEXT
-  if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (property_name_p)) && property_name_p->u.hash & ECMA_GLOBAL_SYMBOL_FLAG)
+  if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (property_name_p)) && property_name_p->u.hash & ECMA_SYMBOL_FLAG_GLOBAL)
   {
-    magic_string_id = (property_name_p->u.hash >> ECMA_GLOBAL_SYMBOL_SHIFT);
+    magic_string_id = (property_name_p->u.hash >> ECMA_SYMBOL_FLAGS_SHIFT);
   }
 #endif /* JERRY_ESNEXT */
 
@@ -1254,9 +1254,9 @@ ecma_builtin_delete_built_in_property (ecma_object_t *object_p, /**< object */
 #if JERRY_ESNEXT
   if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (property_name_p)))
   {
-    if (property_name_p->u.hash & ECMA_GLOBAL_SYMBOL_FLAG)
+    if (property_name_p->u.hash & ECMA_SYMBOL_FLAG_GLOBAL)
     {
-      magic_string_id = (property_name_p->u.hash >> ECMA_GLOBAL_SYMBOL_SHIFT);
+      magic_string_id = (property_name_p->u.hash >> ECMA_SYMBOL_FLAGS_SHIFT);
     }
   }
 #endif /* JERRY_ESNEXT */

jerry-core/ecma/operations/ecma-get-put-value.c

@@ -77,7 +77,7 @@ ecma_op_get_value_lex_env_base (ecma_object_t *lex_env_p, /**< lexical environme
       case ECMA_LEXICAL_ENVIRONMENT_CLASS:
       {
 #if JERRY_MODULE_SYSTEM
-        if (lex_env_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA)
+        if (ECMA_LEX_ENV_CLASS_IS_MODULE (lex_env_p))
         {
           ecma_property_t *property_p = ecma_find_named_property (lex_env_p, name_p);
 
@@ -237,7 +237,7 @@ ecma_op_put_value_lex_env_base (ecma_object_t *lex_env_p, /**< lexical environme
 #if JERRY_ESNEXT
       case ECMA_LEXICAL_ENVIRONMENT_CLASS:
       {
-        if ((lex_env_p->type_flags_refs & ECMA_OBJECT_FLAG_LEXICAL_ENV_HAS_DATA) == 0)
+        if (!ECMA_LEX_ENV_CLASS_IS_MODULE (lex_env_p))
         {
           break;
         }