Empty values in array creation should be not set

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

@@ -79,6 +79,7 @@ typedef enum
   ECMA_SIMPLE_VALUE_NULL, /**< null value */
   ECMA_SIMPLE_VALUE_FALSE, /**< boolean false */
   ECMA_SIMPLE_VALUE_TRUE, /**< boolean true */
+  ECMA_SIMPLE_VALUE_UNUSED, /**< implemenetation defined value to distinguish not initialized values */
   ECMA_SIMPLE_VALUE_ARRAY_REDIRECT, /**< implementation defined value for an array's elements that exist,
                                          but are stored directly in the array's property list
                                          (used for array elements with non-default attribute values) */

jerry-core/ecma/base/ecma-helpers-value.cpp

@@ -112,6 +112,19 @@ ecma_is_value_undefined (ecma_value_t value) /**< ecma-value */
           && ecma_get_value_value_field (value) == ECMA_SIMPLE_VALUE_UNDEFINED);
 } /* ecma_is_value_undefined */
 
+/**
+ * Check if the value is unused.
+ *
+ * @return true - if the value contains implementation-defined unused simple value,
+ *         false - otherwise.
+ */
+bool __attr_pure___ __attr_always_inline___
+ecma_is_value_unused (ecma_value_t value) /**< ecma-value */
+{
+  return (ecma_get_value_type_field (value) == ECMA_TYPE_SIMPLE
+          && ecma_get_value_value_field (value) == ECMA_SIMPLE_VALUE_UNUSED);
+} /* ecma_is_value_unused */
+
 /**
  * Check if the value is null.
  *

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

@@ -55,6 +55,7 @@
 /* ecma-helpers-value.cpp */
 extern bool ecma_is_value_empty (ecma_value_t value);
 extern bool ecma_is_value_undefined (ecma_value_t value);
+extern bool ecma_is_value_unused (ecma_value_t value);
 extern bool ecma_is_value_null (ecma_value_t value);
 extern bool ecma_is_value_boolean (ecma_value_t value);
 extern bool ecma_is_value_true (ecma_value_t value);

jerry-core/ecma/operations/ecma-array-object.cpp

@@ -131,6 +131,11 @@ ecma_op_create_array_object (const ecma_value_t *arguments_list_p, /**< list of
        index < array_items_count;
        index++)
   {
+    if (ecma_is_value_unused (array_items_p[index]))
+    {
+      continue;
+    }
+
     ecma_string_t* item_name_string_p = ecma_new_ecma_string_from_uint32 (index);
 
     ecma_property_descriptor_t item_prop_desc = ecma_make_empty_property_descriptor ();

jerry-core/parser/js/opcodes-dumper.cpp

@@ -985,6 +985,44 @@ dump_undefined_assignment_res (void)
   return op;
 }
 
+/**
+ * Dump unused value assigment for an operand.
+ */
+void
+dump_unused_assignment (operand op) /**< operand */
+{
+  switch (op.type)
+  {
+    case OPERAND_LITERAL:
+    {
+      const opcode_t opcode = getop_assignment (LITERAL_TO_REWRITE,
+                                                OPCODE_ARG_TYPE_SIMPLE,
+                                                ECMA_SIMPLE_VALUE_UNUSED);
+      serializer_dump_op_meta (create_op_meta_100 (opcode, op.data.lit_id));
+      break;
+    }
+    case OPERAND_TMP:
+    {
+      const opcode_t opcode = getop_assignment (op.data.uid, OPCODE_ARG_TYPE_SIMPLE, ECMA_SIMPLE_VALUE_UNUSED);
+      serializer_dump_op_meta (create_op_meta_000 (opcode));
+      break;
+    }
+  }
+} /* dump_unused_assignment */
+
+/**
+ * Dump unused value assigment into a temp operand.
+ *
+ * @return operand with unused value assigned to it.
+ */
+operand
+dump_unused_assignment_res (void)
+{
+  operand op = tmp_operand ();
+  dump_unused_assignment (op);
+  return op;
+} /* dump_unused_assignment_res */
+
 void
 dump_null_assignment (operand op)
 {

jerry-core/parser/js/opcodes-dumper.h

@@ -75,6 +75,8 @@ void dump_smallint_assignment (operand, idx_t);
 operand dump_smallint_assignment_res (idx_t);
 void dump_undefined_assignment (operand);
 operand dump_undefined_assignment_res (void);
+void dump_unused_assignment (operand);
+operand dump_unused_assignment_res (void);
 void dump_null_assignment (operand);
 operand dump_null_assignment_res (void);
 void dump_variable_assignment (operand, operand);

jerry-core/parser/js/parser.cpp

@@ -548,7 +548,7 @@ parse_argument_list (varg_list_type vlt, operand obj, uint8_t *args_count, opera
     {
       if (token_is (TOK_COMMA))
       {
-        op = dump_undefined_assignment_res ();
+        op = dump_unused_assignment_res ();
         dump_varg (op);
       }
       else

jerry-core/vm/pretty-printer.cpp

@@ -259,6 +259,7 @@ pp_op_meta (const opcode_t *opcodes_p,
             case ECMA_SIMPLE_VALUE_FALSE: printf ("false"); break;
             case ECMA_SIMPLE_VALUE_TRUE: printf ("true"); break;
             case ECMA_SIMPLE_VALUE_UNDEFINED: printf ("undefined"); break;
+            case ECMA_SIMPLE_VALUE_UNUSED: printf ("<unused>"); break;
             default: JERRY_UNREACHABLE ();
           }
           printf (": SIMPLE;");

tests/jerry/array.js

@@ -74,7 +74,9 @@ assert(Array.prototype[0] === 'string value');
 
 var c = [0,,,'3'];
 assert (c[0] === 0);
+assert (c.hasOwnProperty("1") === false);
 assert (c[1] === undefined);
+assert (c.hasOwnProperty(2) === false);
 assert (c[2] === undefined);
 assert (c[3] === '3');