From 6f1ce8d6bbd9c0aae15f547da1be34359904e5b2 Mon Sep 17 00:00:00 2001
From: Zoltan Herczeg <zherczeg.u-szeged@partner.samsung.com>
Date: Wed, 13 Jul 2016 04:50:47 -0700
Subject: [PATCH] Improve the construction of "length" built-in strings.

The "length" property name is the most frequently used built-in string
and also frequently created by various hot-paths. New functions are
added to improve the speed of the "length" string creation.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com
---
 jerry-core/ecma/base/ecma-helpers-string.c    | 55 +++++++++++++++++++
 jerry-core/ecma/base/ecma-helpers.h           |  3 +
 .../ecma-builtin-array-prototype.c            | 40 +++++++-------
 .../ecma-builtin-function-prototype.c         |  4 +-
 .../builtin-objects/ecma-builtin-helpers.c    |  2 +-
 .../ecma/builtin-objects/ecma-builtin-json.c  |  4 +-
 .../ecma-builtin-string-prototype.c           |  4 +-
 .../ecma/builtin-objects/ecma-builtins.c      | 26 ++++++---
 .../ecma/operations/ecma-array-object.c       | 12 ++--
 .../ecma/operations/ecma-function-object.c    | 10 +---
 .../ecma/operations/ecma-objects-arguments.c  |  2 +-
 .../ecma/operations/ecma-objects-general.c    | 30 ++--------
 .../ecma/operations/ecma-regexp-object.c      |  2 +-
 .../ecma/operations/ecma-string-object.c      |  2 +-
 jerry-core/jerry.c                            |  6 +-
 jerry-core/lit/lit-globals.h                  |  5 ++
 jerry-core/vm/vm.c                            |  8 +--
 17 files changed, 131 insertions(+), 84 deletions(-)

diff --git a/jerry-core/ecma/base/ecma-helpers-string.c b/jerry-core/ecma/base/ecma-helpers-string.c
index 9caf622637..5ea2a5fc09 100644
--- a/jerry-core/ecma/base/ecma-helpers-string.c
+++ b/jerry-core/ecma/base/ecma-helpers-string.c
@@ -183,6 +183,21 @@ ecma_init_ecma_string_from_uint32 (ecma_string_t *string_desc_p, /**< ecma-strin
   string_desc_p->u.uint32_number = uint32_number;
 } /* ecma_init_ecma_string_from_uint32 */
 
+/**
+ * Initialize a length ecma-string
+ */
+inline void __attr_always_inline___
+ecma_init_ecma_length_string (ecma_string_t *string_desc_p) /**< ecma-string */
+{
+  JERRY_ASSERT (lit_utf8_string_calc_hash ((const lit_utf8_byte_t *) "length", 6) == LIT_STRING_LENGTH_HASH);
+
+  string_desc_p->refs_and_container = ECMA_STRING_CONTAINER_MAGIC_STRING | ECMA_STRING_REF_ONE;
+  string_desc_p->hash = LIT_STRING_LENGTH_HASH;
+
+  string_desc_p->u.common_field = 0;
+  string_desc_p->u.magic_string_id = LIT_MAGIC_STRING_LENGTH;
+} /* ecma_init_ecma_length_string */
+
 /**
  * Allocate new ecma-string and fill it with ecma-number
  *
@@ -280,6 +295,20 @@ ecma_new_ecma_string_from_magic_string_ex_id (lit_magic_string_ex_id_t id) /**<
   return string_desc_p;
 } /* ecma_new_ecma_string_from_magic_string_ex_id */
 
+/**
+ * Allocate new ecma-string and fill it with reference to length magic string
+ *
+ * @return pointer to ecma-string descriptor
+ */
+ecma_string_t *
+ecma_new_ecma_length_string (void)
+{
+  ecma_string_t *string_desc_p = ecma_alloc_string ();
+  ecma_init_ecma_length_string (string_desc_p);
+
+  return string_desc_p;
+} /* ecma_new_ecma_length_string */
+
 /**
  * Concatenate ecma-strings
  *
@@ -761,6 +790,32 @@ ecma_string_is_empty (const ecma_string_t *str_p) /**< ecma-string */
           && str_p->u.magic_string_id == LIT_MAGIC_STRING__EMPTY);
 } /* ecma_string_is_empty */
 
+/**
+ * Checks whether the string equals to "length".
+ *
+ * @return true if the string equals to "length"
+ *         false otherwise
+ */
+inline bool __attr_always_inline___
+ecma_string_is_length (const ecma_string_t *string_p) /**< property name */
+{
+  ecma_string_container_t container = ECMA_STRING_GET_CONTAINER (string_p);
+
+  if (container == ECMA_STRING_CONTAINER_MAGIC_STRING)
+  {
+    return string_p->u.magic_string_id == LIT_MAGIC_STRING_LENGTH;
+  }
+
+  if (container != ECMA_STRING_CONTAINER_HEAP_UTF8_STRING
+      || string_p->u.utf8_string.size != 6
+      || string_p->hash != LIT_STRING_LENGTH_HASH)
+  {
+    return false;
+  }
+
+  return !strncmp ((char *) (string_p + 1), "length", 6);
+} /* ecma_string_is_length */
+
 /**
  * Long path part of ecma-string to ecma-string comparison routine
  *
diff --git a/jerry-core/ecma/base/ecma-helpers.h b/jerry-core/ecma/base/ecma-helpers.h
index bd1623c889..66a730e8a7 100644
--- a/jerry-core/ecma/base/ecma-helpers.h
+++ b/jerry-core/ecma/base/ecma-helpers.h
@@ -168,6 +168,7 @@ extern ecma_string_t *ecma_new_ecma_string_from_uint32 (uint32_t);
 extern ecma_string_t *ecma_new_ecma_string_from_number (ecma_number_t);
 extern ecma_string_t *ecma_new_ecma_string_from_magic_string_id (lit_magic_string_id_t);
 extern ecma_string_t *ecma_new_ecma_string_from_magic_string_ex_id (lit_magic_string_ex_id_t);
+extern ecma_string_t *ecma_new_ecma_length_string ();
 extern ecma_string_t *ecma_concat_ecma_strings (ecma_string_t *, ecma_string_t *);
 extern void ecma_ref_ecma_string (ecma_string_t *);
 extern void ecma_deref_ecma_string (ecma_string_t *);
@@ -179,7 +180,9 @@ ecma_string_copy_to_utf8_buffer (const ecma_string_t *, lit_utf8_byte_t *, lit_u
 extern void ecma_string_to_utf8_bytes (const ecma_string_t *, lit_utf8_byte_t *, lit_utf8_size_t);
 extern const lit_utf8_byte_t *ecma_string_raw_chars (const ecma_string_t *, lit_utf8_size_t *, bool *);
 extern void ecma_init_ecma_string_from_uint32 (ecma_string_t *, uint32_t);
+extern void ecma_init_ecma_length_string (ecma_string_t *);
 extern bool ecma_string_is_empty (const ecma_string_t *);
+extern bool ecma_string_is_length (const ecma_string_t *);
 
 extern bool ecma_compare_ecma_strings_equal_hashes (const ecma_string_t *, const ecma_string_t *);
 extern bool ecma_compare_ecma_strings (const ecma_string_t *, const ecma_string_t *);
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
index 1ac76d8667..12ff96e0eb 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.c
@@ -60,7 +60,7 @@ ecma_builtin_array_prototype_helper_set_length (ecma_object_t *object, /**< obje
                                                 ecma_number_t length) /**< new length */
 {
   ecma_value_t ret_value;
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   ecma_value_t length_value = ecma_make_number_value (length);
   ret_value = ecma_op_object_put (object,
@@ -145,7 +145,7 @@ ecma_builtin_array_prototype_object_to_locale_string (const ecma_value_t this_ar
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_value);
 
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (length_value,
@@ -369,7 +369,7 @@ ecma_builtin_array_prototype_join (const ecma_value_t this_arg, /**< this argume
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_value);
 
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (length_value,
@@ -474,7 +474,7 @@ ecma_builtin_array_prototype_object_pop (ecma_value_t this_arg) /**< this argume
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -555,7 +555,7 @@ ecma_builtin_array_prototype_object_push (ecma_value_t this_arg, /**< this argum
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this_value);
 
   /* 2. */
-  ecma_string_t *length_str_p = ecma_new_ecma_string_from_magic_string_id (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_str_p = ecma_new_ecma_length_string ();
 
   ECMA_TRY_CATCH (length_value, ecma_op_object_get (obj_p, length_str_p), ret_value);
 
@@ -624,7 +624,7 @@ ecma_builtin_array_prototype_object_reverse (ecma_value_t this_arg) /**< this ar
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -720,7 +720,7 @@ ecma_builtin_array_prototype_object_shift (ecma_value_t this_arg) /**< this argu
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -835,7 +835,7 @@ ecma_builtin_array_prototype_object_slice (ecma_value_t this_arg, /**< 'this' ar
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
   ECMA_TRY_CATCH (len_value,
                   ecma_op_object_get (obj_p, length_magic_string_p),
@@ -1205,7 +1205,7 @@ ecma_builtin_array_prototype_object_sort (ecma_value_t this_arg, /**< this argum
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   ECMA_TRY_CATCH (len_value,
                   ecma_op_object_get (obj_p, magic_string_length_p),
@@ -1359,7 +1359,7 @@ ecma_builtin_array_prototype_object_splice (ecma_value_t this_arg, /**< this arg
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
 
   /* 3. */
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
   ECMA_TRY_CATCH (len_value,
                   ecma_op_object_get (obj_p, length_magic_string_p),
@@ -1646,7 +1646,7 @@ ecma_builtin_array_prototype_object_unshift (ecma_value_t this_arg, /**< this ar
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -1742,7 +1742,7 @@ ecma_builtin_array_prototype_object_index_of (ecma_value_t this_arg, /**< this a
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -1838,7 +1838,7 @@ ecma_builtin_array_prototype_object_last_index_of (ecma_value_t this_arg, /**< t
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -1983,7 +1983,7 @@ ecma_builtin_array_prototype_object_every (ecma_value_t this_arg, /**< this argu
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2081,7 +2081,7 @@ ecma_builtin_array_prototype_object_some (ecma_value_t this_arg, /**< this argum
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2178,7 +2178,7 @@ ecma_builtin_array_prototype_object_for_each (ecma_value_t this_arg, /**< this a
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2270,7 +2270,7 @@ ecma_builtin_array_prototype_object_map (ecma_value_t this_arg, /**< this argume
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2380,7 +2380,7 @@ ecma_builtin_array_prototype_object_filter (ecma_value_t this_arg, /**< this arg
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2501,7 +2501,7 @@ ecma_builtin_array_prototype_object_reduce (ecma_value_t this_arg, /**< this arg
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
@@ -2643,7 +2643,7 @@ ecma_builtin_array_prototype_object_reduce_right (ecma_value_t this_arg, /**< th
                   ret_value);
 
   ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
   /* 2. */
   ECMA_TRY_CATCH (len_value,
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-function-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-function-prototype.c
index e34e17b645..56536e8cc9 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-function-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-function-prototype.c
@@ -110,7 +110,7 @@ ecma_builtin_function_prototype_object_apply (ecma_value_t this_arg, /**< this a
       else
       {
         ecma_object_t *obj_p = ecma_get_object_from_value (arg2);
-        ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+        ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
         /* 4. */
         ECMA_TRY_CATCH (length_value,
@@ -286,7 +286,7 @@ ecma_builtin_function_prototype_object_bind (ecma_value_t this_arg, /**< this ar
 
     /* 16. */
     ecma_number_t length = ECMA_NUMBER_ZERO;
-    ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+    ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
 
     /* 15. */
     if (ecma_object_get_class_name (this_arg_obj_p) == LIT_MAGIC_STRING_FUNCTION_UL)
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
index 9128bacfcd..3f43fdabc3 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c
@@ -335,7 +335,7 @@ ecma_builtin_helper_array_concat_value (ecma_object_t *obj_p, /**< array */
   if (ecma_is_value_object (value)
       && (ecma_object_get_class_name (ecma_get_object_from_value (value)) == LIT_MAGIC_STRING_ARRAY_UL))
   {
-    ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+    ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
     /* 5.b.ii */
     ECMA_TRY_CATCH (arg_len_value,
                     ecma_op_object_get (ecma_get_object_from_value (value),
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-json.c b/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
index 7bc811fd91..107217f242 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-json.c
@@ -825,7 +825,7 @@ ecma_builtin_json_stringify (ecma_value_t this_arg, /**< 'this' argument */
     /* 4.b */
     else if (ecma_object_get_class_name (obj_p) == LIT_MAGIC_STRING_ARRAY_UL)
     {
-      ecma_string_t *length_str_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+      ecma_string_t *length_str_p = ecma_new_ecma_length_string ();
 
       ECMA_TRY_CATCH (array_length,
                       ecma_op_object_get (obj_p, length_str_p),
@@ -1624,7 +1624,7 @@ ecma_builtin_json_array (ecma_object_t *obj_p, /**< the array object*/
   /* 5. */
   ecma_collection_header_t *partial_p = ecma_new_values_collection (NULL, 0, true);
 
-  ecma_string_t *length_str_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_str_p = ecma_new_ecma_length_string ();
 
   /* 6. */
   ECMA_TRY_CATCH (array_length,
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
index bebffbec95..3c2db2f99f 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-string-prototype.c
@@ -774,7 +774,7 @@ ecma_builtin_string_prototype_object_replace_get_string (ecma_builtin_replace_se
                                                          ecma_value_t match_value) /**< returned match value */
 {
   ecma_value_t ret_value = ecma_make_simple_value (ECMA_SIMPLE_VALUE_EMPTY);
-  ecma_string_t *length_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_string_p = ecma_new_ecma_length_string ();
   ecma_object_t *match_object_p = ecma_get_object_from_value (match_value);
 
   ECMA_TRY_CATCH (match_length_value,
@@ -1818,7 +1818,7 @@ ecma_builtin_string_prototype_object_split (ecma_value_t this_arg, /**< this arg
               /* 13.c.iii.5 */
               start_pos = end_pos + match_str_length;
 
-              ecma_string_t *magic_length_str_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+              ecma_string_t *magic_length_str_p = ecma_new_ecma_length_string ();
 
               ECMA_TRY_CATCH (array_length_val,
                               ecma_op_object_get (match_array_obj_p, magic_length_str_p),
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtins.c b/jerry-core/ecma/builtin-objects/ecma-builtins.c
index 38a5a0b2b9..7f3b6fb8cc 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtins.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtins.c
@@ -135,6 +135,22 @@ ecma_builtin_init_object (ecma_builtin_id_t obj_builtin_id, /**< built-in ID */
   /** Initializing [[PrimitiveValue]] properties of built-in prototype objects */
   switch (obj_builtin_id)
   {
+#ifndef CONFIG_ECMA_COMPACT_PROFILE_DISABLE_ARRAY_BUILTIN
+    case ECMA_BUILTIN_ID_ARRAY_PROTOTYPE:
+    {
+      ecma_string_t *length_str_p = ecma_new_ecma_length_string ();
+
+      ecma_property_t *length_prop_p = ecma_create_named_data_property (obj_p,
+                                                                        length_str_p,
+                                                                        ECMA_PROPERTY_FLAG_WRITABLE);
+
+      ecma_set_named_data_property_value (length_prop_p, ecma_make_integer_value (0));
+
+      ecma_deref_ecma_string (length_str_p);
+      break;
+    }
+#endif /* !CONFIG_ECMA_COMPACT_PROFILE_DISABLE_ARRAY_BUILTIN */
+
 #ifndef CONFIG_ECMA_COMPACT_PROFILE_DISABLE_STRING_BUILTIN
     case ECMA_BUILTIN_ID_STRING_PROTOTYPE:
     {
@@ -352,13 +368,7 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
   if (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_FUNCTION
       && ecma_builtin_function_is_routine (object_p))
   {
-    ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
-
-    bool is_length_property = ecma_compare_ecma_strings (string_p, magic_string_length_p);
-
-    ecma_deref_ecma_string (magic_string_length_p);
-
-    if (is_length_property)
+    if (ecma_string_is_length (string_p))
     {
       /*
        * Lazy instantiation of 'length' property
@@ -589,7 +599,7 @@ ecma_builtin_list_lazy_property_names (ecma_object_t *object_p, /**< a built-in
     ecma_collection_header_t *for_non_enumerable_p = separate_enumerable ? non_enum_collection_p : main_collection_p;
 
     /* 'length' property is non-enumerable (ECMA-262 v5, 15) */
-    ecma_string_t *name_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+    ecma_string_t *name_p = ecma_new_ecma_length_string ();
     ecma_append_to_values_collection (for_non_enumerable_p, ecma_make_string_value (name_p), true);
     ecma_deref_ecma_string (name_p);
   }
diff --git a/jerry-core/ecma/operations/ecma-array-object.c b/jerry-core/ecma/operations/ecma-array-object.c
index 926d27f0b8..3e97828ad3 100644
--- a/jerry-core/ecma/operations/ecma-array-object.c
+++ b/jerry-core/ecma/operations/ecma-array-object.c
@@ -103,7 +103,7 @@ 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_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
 
   ecma_property_t *length_prop_p = ecma_create_named_data_property (obj_p,
                                                                     length_magic_string_p,
@@ -157,7 +157,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
   JERRY_ASSERT (ecma_get_object_type (obj_p) == ECMA_OBJECT_TYPE_ARRAY);
 
   // 1.
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
   ecma_property_t *len_prop_p = ecma_op_object_get_own_property (obj_p, magic_string_length_p);
   JERRY_ASSERT (len_prop_p != NULL && ECMA_PROPERTY_GET_TYPE (len_prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA);
 
@@ -214,7 +214,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
       if (new_len_uint32 >= old_len_uint32)
       {
         // i.
-        magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+        magic_string_length_p = ecma_new_ecma_length_string ();
         ret_value = ecma_op_general_object_define_own_property (obj_p,
                                                                 magic_string_length_p,
                                                                 &new_len_property_desc,
@@ -248,7 +248,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
           }
 
           // j.
-          magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+          magic_string_length_p = ecma_new_ecma_length_string ();
           ecma_value_t succeeded = ecma_op_general_object_define_own_property (obj_p,
                                                                                magic_string_length_p,
                                                                                &new_len_property_desc,
@@ -329,7 +329,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
                 }
 
                 // 3.
-                ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+                ecma_string_t *magic_string_length_p = ecma_new_ecma_length_string ();
                 ecma_value_t completion = ecma_op_general_object_define_own_property (obj_p,
                                                                                       magic_string_length_p,
                                                                                       &new_len_property_desc,
@@ -363,7 +363,7 @@ ecma_op_array_object_define_own_property (ecma_object_t *obj_p, /**< the array o
                 prop_desc_not_writable.is_writable = false;
 
                 ecma_value_t completion_set_not_writable;
-                magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+                magic_string_length_p = ecma_new_ecma_length_string ();
                 completion_set_not_writable = ecma_op_general_object_define_own_property (obj_p,
                                                                                           magic_string_length_p,
                                                                                           &prop_desc_not_writable,
diff --git a/jerry-core/ecma/operations/ecma-function-object.c b/jerry-core/ecma/operations/ecma-function-object.c
index 696dfd5dca..72213a7281 100644
--- a/jerry-core/ecma/operations/ecma-function-object.c
+++ b/jerry-core/ecma/operations/ecma-function-object.c
@@ -255,7 +255,7 @@ ecma_op_function_list_lazy_property_names (bool separate_enumerable, /**< true -
   ecma_string_t *name_p;
 
   /* 'length' property is non-enumerable (ECMA-262 v5, 13.2.5) */
-  name_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  name_p = ecma_new_ecma_length_string ();
   ecma_append_to_values_collection (for_non_enumerable_p, ecma_make_string_value (name_p), true);
   ecma_deref_ecma_string (name_p);
 
@@ -282,13 +282,7 @@ ecma_op_function_try_lazy_instantiate_property (ecma_object_t *obj_p, /**< the f
 {
   JERRY_ASSERT (!ecma_get_object_is_builtin (obj_p));
 
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
-
-  bool is_length_property = ecma_compare_ecma_strings (magic_string_length_p, property_name_p);
-
-  ecma_deref_ecma_string (magic_string_length_p);
-
-  if (is_length_property)
+  if (ecma_string_is_length (property_name_p))
   {
     /* ECMA-262 v5, 13.2, 14-15 */
     ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) obj_p;
diff --git a/jerry-core/ecma/operations/ecma-objects-arguments.c b/jerry-core/ecma/operations/ecma-objects-arguments.c
index 2786b06fab..d738768682 100644
--- a/jerry-core/ecma/operations/ecma-objects-arguments.c
+++ b/jerry-core/ecma/operations/ecma-objects-arguments.c
@@ -85,7 +85,7 @@ ecma_op_create_arguments_object (ecma_object_t *func_obj_p, /**< callee function
   ECMA_PROPERTY_VALUE_PTR (class_prop_p)->value = LIT_MAGIC_STRING_ARGUMENTS_UL;
 
   // 7.
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
   ecma_value_t completion = ecma_builtin_helper_def_prop (obj_p,
                                                           length_magic_string_p,
                                                           ecma_make_uint32_value (arguments_number),
diff --git a/jerry-core/ecma/operations/ecma-objects-general.c b/jerry-core/ecma/operations/ecma-objects-general.c
index fbdb4c20e4..c7375eaf6a 100644
--- a/jerry-core/ecma/operations/ecma-objects-general.c
+++ b/jerry-core/ecma/operations/ecma-objects-general.c
@@ -245,25 +245,6 @@ ecma_op_general_object_get_property (ecma_object_t *obj_p, /**< the object */
   }
 } /* ecma_op_general_object_get_property */
 
-/**
- * Checks whether the property name is "length".
- *
- * @return true if the property name is length
- *         false otherwise
- */
-static inline bool __attr_always_inline___
-ecma_op_general_object_property_name_is_length (ecma_string_t *property_name_p) /**< property name */
-{
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
-
-  bool property_name_is_length = ecma_compare_ecma_strings (property_name_p,
-                                                            magic_string_length_p);
-
-  ecma_deref_ecma_string (magic_string_length_p);
-
-  return property_name_is_length;
-} /* ecma_op_general_object_property_name_is_length */
-
 /**
  * [[Put]] ecma general object's operation
  *
@@ -305,7 +286,7 @@ ecma_op_general_object_put (ecma_object_t *obj_p, /**< the object */
         const ecma_object_type_t type = ecma_get_object_type (obj_p);
 
         if (type == ECMA_OBJECT_TYPE_ARGUMENTS
-            || (type == ECMA_OBJECT_TYPE_ARRAY && ecma_op_general_object_property_name_is_length (property_name_p)))
+            || (type == ECMA_OBJECT_TYPE_ARRAY && ecma_string_is_length (property_name_p)))
         {
           /* These cases cannot be optimized. */
           ecma_property_descriptor_t value_desc = ecma_make_empty_property_descriptor ();
@@ -379,11 +360,12 @@ ecma_op_general_object_put (ecma_object_t *obj_p, /**< the object */
         /* Since the length of an array is a non-configurable named data
          * property, the prop_p must be a non-NULL pointer for all arrays. */
 
-        JERRY_ASSERT (!ecma_op_general_object_property_name_is_length (property_name_p));
+        JERRY_ASSERT (!ecma_string_is_length (property_name_p));
+
+        ecma_string_t magic_string_length;
+        ecma_init_ecma_length_string (&magic_string_length);
 
-        ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
-        ecma_property_t *len_prop_p = ecma_op_object_get_own_property (obj_p, magic_string_length_p);
-        ecma_deref_ecma_string (magic_string_length_p);
+        ecma_property_t *len_prop_p = ecma_op_object_get_own_property (obj_p, &magic_string_length);
 
         JERRY_ASSERT (len_prop_p != NULL
                       && ECMA_PROPERTY_GET_TYPE (len_prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA);
diff --git a/jerry-core/ecma/operations/ecma-regexp-object.c b/jerry-core/ecma/operations/ecma-regexp-object.c
index ef87176da1..e3f495c7a3 100644
--- a/jerry-core/ecma/operations/ecma-regexp-object.c
+++ b/jerry-core/ecma/operations/ecma-regexp-object.c
@@ -1199,7 +1199,7 @@ re_set_result_array_properties (ecma_object_t *array_obj_p, /**< result array */
   ecma_deref_ecma_string (result_prop_str_p);
 
   /* Set length property of the result array */
-  result_prop_str_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  result_prop_str_p = ecma_new_ecma_length_string ();
   {
     ecma_property_descriptor_t array_item_prop_desc = ecma_make_empty_property_descriptor ();
     array_item_prop_desc.is_value_defined = true;
diff --git a/jerry-core/ecma/operations/ecma-string-object.c b/jerry-core/ecma/operations/ecma-string-object.c
index 25b6bfd4a8..acc92ab092 100644
--- a/jerry-core/ecma/operations/ecma-string-object.c
+++ b/jerry-core/ecma/operations/ecma-string-object.c
@@ -99,7 +99,7 @@ ecma_op_create_string_object (const ecma_value_t *arguments_list_p, /**< list of
   ecma_set_internal_property_value (prim_value_prop_p, ecma_make_string_value (prim_prop_str_value_p));
 
   // 15.5.5.1
-  ecma_string_t *length_magic_string_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t *length_magic_string_p = ecma_new_ecma_length_string ();
   ecma_property_t *length_prop_p = ecma_create_named_data_property (obj_p,
                                                                     length_magic_string_p,
                                                                     ECMA_PROPERTY_FIXED);
diff --git a/jerry-core/jerry.c b/jerry-core/jerry.c
index 65cdaf0dfc..49479f5091 100644
--- a/jerry-core/jerry.c
+++ b/jerry-core/jerry.c
@@ -942,11 +942,11 @@ jerry_get_array_length (const jerry_value_t value)
   }
 
   jerry_length_t length = 0;
-  ecma_string_t *magic_string_length_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
+  ecma_string_t magic_string_length;
+  ecma_init_ecma_length_string (&magic_string_length);
 
   ecma_value_t len_value = ecma_op_object_get (ecma_get_object_from_value (value),
-                                               magic_string_length_p);
-  ecma_deref_ecma_string (magic_string_length_p);
+                                               &magic_string_length);
 
   length = ecma_number_to_uint32 (ecma_get_number_from_value (len_value));
   ecma_free_value (len_value);
diff --git a/jerry-core/lit/lit-globals.h b/jerry-core/lit/lit-globals.h
index 8081571595..b5b6071399 100644
--- a/jerry-core/lit/lit-globals.h
+++ b/jerry-core/lit/lit-globals.h
@@ -139,4 +139,9 @@ typedef uint16_t lit_string_hash_t;
  */
 #define LIT_STRING_HASH_LIMIT 0x10000u
 
+/**
+ * Hash of the frequently used "length" string.
+ */
+#define LIT_STRING_LENGTH_HASH 0x3615u
+
 #endif /* !LIT_GLOBALS_H */
diff --git a/jerry-core/vm/vm.c b/jerry-core/vm/vm.c
index 0ef671932f..94adde6bde 100644
--- a/jerry-core/vm/vm.c
+++ b/jerry-core/vm/vm.c
@@ -1002,7 +1002,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
         case VM_OC_APPEND_ARRAY:
         {
           ecma_object_t *array_obj_p;
-          ecma_string_t *length_str_p;
+          ecma_string_t length_str;
           ecma_property_t *length_prop_p;
           uint32_t length_num;
           uint32_t values_length = *byte_code_p++;
@@ -1010,16 +1010,14 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
           stack_top_p -= values_length;
 
           array_obj_p = ecma_get_object_from_value (stack_top_p[-1]);
-          length_str_p = ecma_get_magic_string (LIT_MAGIC_STRING_LENGTH);
-          length_prop_p = ecma_get_named_property (array_obj_p, length_str_p);
+          ecma_init_ecma_length_string (&length_str);
+          length_prop_p = ecma_get_named_property (array_obj_p, &length_str);
 
           JERRY_ASSERT (length_prop_p != NULL);
 
           left_value = ecma_get_named_data_property_value (length_prop_p);
           length_num = ecma_get_uint32_from_value (left_value);
 
-          ecma_deref_ecma_string (length_str_p);
-
           for (uint32_t i = 0; i < values_length; i++)
           {
             if (!ecma_is_value_array_hole (stack_top_p[i]))