diff -r 000000000000 -r 6474c204b198 js/src/gc/Barrier-inl.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/gc/Barrier-inl.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+/* -*- 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/. */
+
+#ifndef gc_Barrier_inl_h
+#define gc_Barrier_inl_h
+
+#include "gc/Barrier.h"
+
+namespace js {
+
+inline const Value &
+ReadBarrieredValue::get() const
+{
+    if (value.isObject())
+        JSObject::readBarrier(&value.toObject());
+    else if (value.isString())
+        JSString::readBarrier(value.toString());
+    else
+        JS_ASSERT(!value.isMarkable());
+
+    return value;
+}
+
+inline
+ReadBarrieredValue::operator const Value &() const
+{
+    return get();
+}
+
+inline JSObject &
+ReadBarrieredValue::toObject() const
+{
+    return get().toObject();
+}
+
+} /* namespace js */
+
+#endif /* gc_Barrier_inl_h */