diff -r 000000000000 -r 6474c204b198 js/src/builtin/SelfHostingDefines.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/builtin/SelfHostingDefines.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Specialized .h file to be used by both JS and C++ code.
+
+#ifndef builtin_SelfHostingDefines_h
+#define builtin_SelfHostingDefines_h
+
+// Utility macros.
+#define TO_INT32(x) ((x) | 0)
+#define TO_UINT32(x) ((x) >>> 0)
+#define IS_UINT32(x) ((x) >>> 0 === (x))
+
+// Assertions.
+#ifdef DEBUG
+#define assert(b, info) if (!(b)) AssertionFailed(info)
+#else
+#define assert(b, info) // Elided assertion.
+#endif
+
+// Unforgeable versions of ARRAY.push(ELEMENT) and ARRAY.slice.
+#define ARRAY_PUSH(ARRAY, ELEMENT) \
+  callFunction(std_Array_push, ARRAY, ELEMENT);
+#define ARRAY_SLICE(ARRAY, ELEMENT) \
+  callFunction(std_Array_slice, ARRAY, ELEMENT);
+
+// Property descriptor attributes.
+#define ATTR_ENUMERABLE         0x01
+#define ATTR_CONFIGURABLE       0x02
+#define ATTR_WRITABLE           0x04
+
+#define ATTR_NONENUMERABLE      0x08
+#define ATTR_NONCONFIGURABLE    0x10
+#define ATTR_NONWRITABLE        0x20
+
+#endif