diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/runtime/threadLocalStorage.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/threadLocalStorage.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP
+#define SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP
+
+#include "memory/allocation.hpp"
+
+// forward-decl as we can't have an include cycle
+class Thread;
+
+// Wrapper class for library-based (as opposed to compiler-based)
+// thread-local storage (TLS). All platforms require this for
+// signal-handler based TLS access (which while not strictly async-signal
+// safe in theory, is and has-been for a long time, in practice).
+// Platforms without compiler-based TLS (i.e. __thread storage-class modifier)
+// will use this implementation for all TLS access - see thread.hpp/cpp
+
+class ThreadLocalStorage : AllStatic {
+
+ // Exported API
+ public:
+  static Thread* thread(); // return current thread, if attached
+  static void    set_thread(Thread* thread); // set current thread
+  static void    init();
+  static bool    is_initialized(); // can't use TLS prior to initialization
+};
+
+#endif // SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP