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Change array length into a virtual property. (#1439)

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This change allows easier access to array length which improves
the performance of inserting new items into an array and there
is no need to allocate length strings anymore. The trade-of is
that array length cannot be cached anymore.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com
This commit is contained in:
Zoltan Herczeg
2016-11-22 13:29:53 +01:00
committed by GitHub
parent 4a0f78bc4b
commit 132477f7d5
8 changed files with 236 additions and 152 deletions
Download Patch File Download Diff File Expand all files Collapse all files
jerry-core/ecma/operations/ecma-array-object.c
+66 -49
View File
@@ -86,16 +86,16 @@ ecma_op_create_array_object (const ecma_value_t *arguments_list_p, /**< list of
}
#ifndef CONFIG_DISABLE_ARRAY_BUILTIN
ecma_object_t *array_prototype_obj_p = ecma_builtin_get (ECMA_BUILTIN_ID_ARRAY_PROTOTYPE);
ecma_object_t *array_prototype_object_p = ecma_builtin_get (ECMA_BUILTIN_ID_ARRAY_PROTOTYPE);
#else /* CONFIG_DISABLE_ARRAY_BUILTIN */
ecma_object_t *array_prototype_obj_p = ecma_builtin_get (ECMA_BUILTIN_ID_OBJECT_PROTOTYPE);
ecma_object_t *array_prototype_object_p = ecma_builtin_get (ECMA_BUILTIN_ID_OBJECT_PROTOTYPE);
#endif /* !CONFIG_DISABLE_ARRAY_BUILTIN */
ecma_object_t *obj_p = ecma_create_object (array_prototype_obj_p,
0,
ECMA_OBJECT_TYPE_ARRAY);
ecma_object_t *object_p = ecma_create_object (array_prototype_object_p,
sizeof (ecma_extended_object_t),
ECMA_OBJECT_TYPE_ARRAY);
ecma_deref_object (array_prototype_obj_p);
ecma_deref_object (array_prototype_object_p);
/*
* [[Class]] property is not stored explicitly for objects of ECMA_OBJECT_TYPE_ARRAY type.
@@ -103,17 +103,9 @@ ecma_op_create_array_object (const ecma_value_t *arguments_list_p, /**< list of
* See also: ecma_object_get_class_name
*/
ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
ecma_property_value_t *length_prop_value_p;
length_prop_value_p = ecma_create_named_data_property (obj_p,
length_magic_string_p,
ECMA_PROPERTY_FLAG_WRITABLE,
NULL);
length_prop_value_p->value = ecma_make_number_value ((ecma_number_t) length);
ecma_deref_ecma_string (length_magic_string_p);
ecma_extended_object_t *ext_obj_p = (ecma_extended_object_t *) object_p;
ext_obj_p->u.array.length = length;
ext_obj_p->u.array.length_prop = ECMA_PROPERTY_FLAG_WRITABLE | ECMA_PROPERTY_TYPE_VIRTUAL;
for (uint32_t index = 0;
index < array_items_count;
@@ -126,7 +118,7 @@ ecma_op_create_array_object (const ecma_value_t *arguments_list_p, /**< list of
ecma_string_t *item_name_string_p = ecma_new_ecma_string_from_uint32 (index);
ecma_builtin_helper_def_prop (obj_p,
ecma_builtin_helper_def_prop (object_p,
item_name_string_p,
array_items_p[index],
true, /* Writable */
@@ -137,7 +129,7 @@ ecma_op_create_array_object (const ecma_value_t *arguments_list_p, /**< list of
ecma_deref_ecma_string (item_name_string_p);
}
return ecma_make_object_value (obj_p);
return ecma_make_object_value (object_p);
} /* ecma_op_create_array_object */
/**
@@ -192,15 +184,9 @@ ecma_op_array_object_set_length (ecma_object_t *object_p, /**< the array object
return ecma_reject (is_throw);
}
ecma_string_t magic_string_length;
ecma_init_ecma_length_string (&magic_string_length);
ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
ecma_property_t *len_prop_p = ecma_find_named_property (object_p, &magic_string_length);
JERRY_ASSERT (len_prop_p != NULL
&& ECMA_PROPERTY_GET_TYPE (*len_prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA);
ecma_property_value_t *len_prop_value_p = ECMA_PROPERTY_VALUE_PTR (len_prop_p);
uint32_t old_len_uint32 = ecma_get_uint32_from_value (len_prop_value_p->value);
uint32_t old_len_uint32 = ext_object_p->u.array.length;
if (new_len_num == old_len_uint32)
{
@@ -209,16 +195,17 @@ ecma_op_array_object_set_length (ecma_object_t *object_p, /**< the array object
{
if (!(flags & ECMA_ARRAY_OBJECT_SET_LENGTH_FLAG_WRITABLE))
{
ecma_set_property_writable_attr (len_prop_p, false);
uint8_t new_prop_value = (uint8_t) (ext_object_p->u.array.length_prop & ~ECMA_PROPERTY_FLAG_WRITABLE);
ext_object_p->u.array.length_prop = new_prop_value;
}
else if (!ecma_is_property_writable (*len_prop_p))
else if (!ecma_is_property_writable (ext_object_p->u.array.length_prop))
{
return ecma_reject (is_throw);
}
}
return ecma_make_simple_value (ECMA_SIMPLE_VALUE_TRUE);
}
else if (!ecma_is_property_writable (*len_prop_p))
else if (!ecma_is_property_writable (ext_object_p->u.array.length_prop))
{
return ecma_reject (is_throw);
}
@@ -230,12 +217,13 @@ ecma_op_array_object_set_length (ecma_object_t *object_p, /**< the array object
current_len_uint32 = ecma_delete_array_properties (object_p, new_len_uint32, old_len_uint32);
}
ecma_value_assign_uint32 (&len_prop_value_p->value, current_len_uint32);
ext_object_p->u.array.length = current_len_uint32;
if ((flags & ECMA_ARRAY_OBJECT_SET_LENGTH_FLAG_WRITABLE_DEFINED)
&& !(flags & ECMA_ARRAY_OBJECT_SET_LENGTH_FLAG_WRITABLE))
{
ecma_set_property_writable_attr (len_prop_p, false);
uint8_t new_prop_value = (uint8_t) (ext_object_p->u.array.length_prop & ~ECMA_PROPERTY_FLAG_WRITABLE);
ext_object_p->u.array.length_prop = new_prop_value;
}
if (current_len_uint32 == new_len_uint32)
@@ -263,11 +251,6 @@ ecma_op_array_object_define_own_property (ecma_object_t *object_p, /**< the arra
{
if (ecma_string_is_length (property_name_p))
{
if (!property_desc_p->is_value_defined)
{
return ecma_op_general_object_define_own_property (object_p, property_name_p, property_desc_p, is_throw);
}
JERRY_ASSERT (property_desc_p->is_configurable_defined || !property_desc_p->is_configurable);
JERRY_ASSERT (property_desc_p->is_enumerable_defined || !property_desc_p->is_enumerable);
JERRY_ASSERT (property_desc_p->is_writable_defined || !property_desc_p->is_writable);
@@ -298,7 +281,18 @@ ecma_op_array_object_define_own_property (ecma_object_t *object_p, /**< the arra
flags |= ECMA_ARRAY_OBJECT_SET_LENGTH_FLAG_WRITABLE;
}
return ecma_op_array_object_set_length (object_p, property_desc_p->value, flags);
if (property_desc_p->is_value_defined)
{
return ecma_op_array_object_set_length (object_p, property_desc_p->value, flags);
}
ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
ecma_value_t length_value = ecma_make_uint32_value (ext_object_p->u.array.length);
ecma_value_t result = ecma_op_array_object_set_length (object_p, length_value, flags);
ecma_fast_free_value (length_value);
return result;
}
uint32_t index = ecma_string_get_array_index (property_name_p);
@@ -308,18 +302,11 @@ ecma_op_array_object_define_own_property (ecma_object_t *object_p, /**< the arra
return ecma_op_general_object_define_own_property (object_p, property_name_p, property_desc_p, is_throw);
}
ecma_string_t magic_string_length;
ecma_init_ecma_length_string (&magic_string_length);
ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
ecma_property_t *len_prop_p = ecma_find_named_property (object_p, &magic_string_length);
JERRY_ASSERT (len_prop_p != NULL
&& ECMA_PROPERTY_GET_TYPE (*len_prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA);
bool update_length = (index >= ext_object_p->u.array.length);
ecma_property_value_t *len_prop_value_p = ECMA_PROPERTY_VALUE_PTR (len_prop_p);
bool update_length = (index >= ecma_get_uint32_from_value (len_prop_value_p->value));
if (update_length && !ecma_is_property_writable (*len_prop_p))
if (update_length && !ecma_is_property_writable (ext_object_p->u.array.length_prop))
{
return ecma_reject (is_throw);
}
@@ -337,11 +324,41 @@ ecma_op_array_object_define_own_property (ecma_object_t *object_p, /**< the arra
if (update_length)
{
ecma_value_assign_uint32 (&len_prop_value_p->value, index + 1);
ext_object_p->u.array.length = index + 1;
}
return ecma_make_simple_value (ECMA_SIMPLE_VALUE_TRUE);
} /* ecma_op_array_object_define_own_property */
/**
* List names of a String object's lazy instantiated properties
*
* @return string values collection
*/
void
ecma_op_array_list_lazy_property_names (ecma_object_t *obj_p, /**< a String object */
bool separate_enumerable, /**< true - list enumerable properties
* into main collection,
* and non-enumerable to collection of
* 'skipped non-enumerable' properties,
* false - list all properties into main
* collection.
*/
ecma_collection_header_t *main_collection_p, /**< 'main'
* collection */
ecma_collection_header_t *non_enum_collection_p) /**< skipped
* 'non-enumerable'
* collection */
{
JERRY_ASSERT (ecma_get_object_type (obj_p) == ECMA_OBJECT_TYPE_ARRAY);
ecma_collection_header_t *for_non_enumerable_p = separate_enumerable ? non_enum_collection_p : main_collection_p;
ecma_string_t *length_str_p = ecma_new_ecma_length_string ();
ecma_append_to_values_collection (for_non_enumerable_p, ecma_make_string_value (length_str_p), true);
ecma_deref_ecma_string (length_str_p);
} /* ecma_op_array_list_lazy_property_names */
/**
* @}
* @}