[runtime] fix getting element keys from SLOW_SLOPPY_ARGUMENTS_ELEMENTS

test/mjsunit/regress/regress-4825.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function enumerate(o) {
+  var keys = [];
+  for (var key in o) keys.push(key);
+  return keys;
+}
+
+(function testSlowSloppyArgumentsElements()  {
+  function slowSloppyArguments(a, b, c) {
+    arguments[10000] = "last";
+    arguments[4000] = "first";
+    arguments[6000] = "second";
+    arguments[5999] = "x";
+    arguments[3999] = "y";
+    return arguments;
+  }
+  assertEquals(["0", "1", "2", "3999", "4000", "5999", "6000", "10000"],
+               Object.keys(slowSloppyArguments(1, 2, 3)));
+
+  assertEquals(["0", "1", "2", "3999", "4000", "5999", "6000", "10000"],
+               enumerate(slowSloppyArguments(1,2,3)));
+})();
+
+(function testSlowSloppyArgumentsElementsNotEnumerable() {
+  function slowSloppyArguments(a, b, c) {
+    Object.defineProperty(arguments, 10000, {
+      enumerable: false, configurable: false, value: "NOPE"
+    });
+    arguments[4000] = "first";
+    arguments[6000] = "second";
+    arguments[5999] = "x";
+    arguments[3999] = "y";
+    return arguments;
+  }
+
+  assertEquals(["0", "1", "2", "3999", "4000", "5999", "6000"],
+               Object.keys(slowSloppyArguments(1, 2, 3)));
+
+  assertEquals(["0", "1", "2", "3999", "4000", "5999", "6000"],
+                enumerate(slowSloppyArguments(1,2,3)));
+})();
+
+(function testFastSloppyArgumentsElements()  {
+  function fastSloppyArguments(a, b, c) {
+    arguments[5] = 1;
+    arguments[7] = 0;
+    arguments[3] = 2;
+    return arguments;
+  }
+  assertEquals(["0", "1", "2", "3", "5", "7"],
+               Object.keys(fastSloppyArguments(1, 2, 3)));
+
+  assertEquals(
+      ["0", "1", "2", "3", "5", "7"], enumerate(fastSloppyArguments(1, 2, 3)));
+
+  function fastSloppyArguments2(a, b, c) {
+    delete arguments[0];
+    arguments[0] = "test";
+    return arguments;
+  }
+
+  assertEquals(["0", "1", "2"], Object.keys(fastSloppyArguments2(1, 2, 3)));
+  assertEquals(["0", "1", "2"], enumerate(fastSloppyArguments2(1, 2, 3)));
+})();
+
+(function testFastSloppyArgumentsElementsNotEnumerable() {
+  function fastSloppyArguments(a, b, c) {
+    Object.defineProperty(arguments, 5, {
+      enumerable: false, configurable: false, value: "NOPE"
+    });
+    arguments[7] = 0;
+    arguments[3] = 2;
+    return arguments;
+  }
+  assertEquals(
+      ["0", "1", "2", "3", "7"], Object.keys(fastSloppyArguments(1, 2, 3)));
+
+  assertEquals(
+      ["0", "1", "2", "3", "7"], enumerate(fastSloppyArguments(1,2,3)));
+
+  function fastSloppyArguments2(a, b, c) {
+    delete arguments[0];
+    Object.defineProperty(arguments, 1, {
+      enumerable: false, configurable: false, value: "NOPE"
+    });
+    arguments[0] = "test";
+    return arguments;
+  }
+
+  assertEquals(["0", "2"], Object.keys(fastSloppyArguments2(1, 2, 3)));
+  assertEquals(["0", "2"], enumerate(fastSloppyArguments2(1, 2, 3)));
+})();