Rework arguments object. (#1401)

Instead of allocating a helper object, argument names are appended right
after the arguments objects. This reduces memory consumption and improve
performance as well. In the future this could be further improved by a
bitfield, but that would require a reference to the byte code which
might increase memory consumption in a few corner cases.

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

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

@@ -247,8 +247,6 @@ ecma_gc_mark_property (ecma_property_t *property_p) /**< property */
         }
 
         case ECMA_INTERNAL_PROPERTY_BOUND_FUNCTION_TARGET_FUNCTION: /* an object */
-        case ECMA_INTERNAL_PROPERTY_SCOPE: /* a lexical environment */
-        case ECMA_INTERNAL_PROPERTY_PARAMETERS_MAP: /* an object */
         {
           ecma_object_t *obj_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_object_t, property_value);
 
@@ -308,8 +306,17 @@ ecma_gc_mark (ecma_object_t *object_p) /**< object to mark from */
       ecma_gc_set_object_visited (proto_p, true);
     }
 
-    if (!ecma_get_object_is_builtin (object_p)
-        && ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_FUNCTION)
+    if (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_ARGUMENTS)
+    {
+      ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
+
+      ecma_object_t *lex_env_p = ECMA_GET_INTERNAL_VALUE_POINTER (ecma_object_t,
+                                                                  ext_object_p->u.arguments.lex_env_cp);
+
+      ecma_gc_set_object_visited (lex_env_p, true);
+    }
+    else if (!ecma_get_object_is_builtin (object_p)
+             && ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_FUNCTION)
     {
       ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
 
@@ -436,7 +443,9 @@ ecma_gc_sweep (ecma_object_t *object_p) /**< object to free */
 
   if (!ecma_is_lexical_environment (object_p))
   {
-    if (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_CLASS)
+    ecma_object_type_t object_type = ecma_get_object_type (object_p);
+
+    if (object_type == ECMA_OBJECT_TYPE_CLASS)
     {
       ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
 
@@ -491,13 +500,13 @@ ecma_gc_sweep (ecma_object_t *object_p) /**< object to free */
     }
 
     if (ecma_get_object_is_builtin (object_p)
-        || ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_EXTERNAL_FUNCTION)
+        || object_type == ECMA_OBJECT_TYPE_EXTERNAL_FUNCTION)
     {
       ecma_dealloc_extended_object ((ecma_extended_object_t *) object_p, sizeof (ecma_extended_object_t));
       return;
     }
 
-    if (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_FUNCTION)
+    if (object_type == ECMA_OBJECT_TYPE_FUNCTION)
     {
       /* Function with byte-code (not a built-in function). */
       ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
@@ -508,6 +517,27 @@ ecma_gc_sweep (ecma_object_t *object_p) /**< object to free */
       ecma_dealloc_extended_object (ext_func_p, sizeof (ecma_extended_object_t));
       return;
     }
+
+    if (object_type == ECMA_OBJECT_TYPE_ARGUMENTS)
+    {
+      ecma_extended_object_t *ext_object_p = (ecma_extended_object_t *) object_p;
+
+      ecma_length_t formal_params_number = ext_object_p->u.arguments.length;
+      jmem_cpointer_t *arg_Literal_p = (jmem_cpointer_t *) (ext_object_p + 1);
+
+      for (ecma_length_t i = 0; i < formal_params_number; i++)
+      {
+        if (arg_Literal_p[i] != JMEM_CP_NULL)
+        {
+          ecma_string_t *name_p = JMEM_CP_GET_NON_NULL_POINTER (ecma_string_t, arg_Literal_p[i]);
+          ecma_deref_ecma_string (name_p);
+        }
+      }
+
+      size_t formal_params_size = formal_params_number * sizeof (jmem_cpointer_t);
+      ecma_dealloc_extended_object (ext_object_p, sizeof (ecma_extended_object_t) + formal_params_size);
+      return;
+    }
   }
 
   ecma_dealloc_object (object_p);

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

@@ -197,9 +197,6 @@ typedef uintptr_t ecma_external_pointer_t;
  */
 typedef enum
 {
-  ECMA_INTERNAL_PROPERTY_SCOPE, /**< [[Scope]] */
-  ECMA_INTERNAL_PROPERTY_PARAMETERS_MAP, /**< [[ParametersMap]] */
-
   ECMA_INTERNAL_PROPERTY_NATIVE_HANDLE, /**< native handle associated with an object */
   ECMA_INTERNAL_PROPERTY_FREE_CALLBACK, /**< object's native free callback */
 
@@ -606,6 +603,15 @@ typedef struct
       ecma_value_t bytecode_cp; /**< function byte code */
     } function;
 
+    /*
+     * Description of arguments objects.
+     */
+    struct
+    {
+      ecma_value_t lex_env_cp; /**< lexical environment */
+      uint32_t length; /**< length of names */
+    } arguments;
+
     ecma_external_pointer_t external_function; /**< external function */
   } u;
 } ecma_extended_object_t;

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

@@ -783,8 +783,6 @@ ecma_free_internal_property (ecma_property_t *property_p) /**< the property */
       break;
     }
 
-    case ECMA_INTERNAL_PROPERTY_SCOPE: /* a lexical environment */
-    case ECMA_INTERNAL_PROPERTY_PARAMETERS_MAP: /* an object */
     case ECMA_INTERNAL_PROPERTY_INSTANTIATED_MASK_32_63: /* an integer (bit-mask) */
     case ECMA_INTERNAL_PROPERTY_BOUND_FUNCTION_TARGET_FUNCTION:
     {