1 /* 2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP 26 #define SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP 27 28 #include "utilities/top.hpp" 29 30 // forward-decl as we can't have an include cycle 31 class Thread; 32 33 // Wrapper class for library-based (as opposed to compiler-based) 34 // thread-local storage (TLS). All platforms require this for 35 // signal-handler based TLS access (which while not strictly async-signal 36 // safe in theory, is and has-been for a long time, in practice). 37 // Platforms without compiler-based TLS (i.e. __thread storage-class modifier) 38 // will use this implementation for all TLS access - see thread.hpp/cpp 39 40 class ThreadLocalStorage : AllStatic { 41 42 // Exported API 43 public: 44 static Thread* thread(); // return current thread, if attached 45 static void set_thread(Thread* thread); // set current thread 46 static void init(); 47 static bool is_initialized(); // can't use TLS prior to initialization 48 }; 49 50 #endif // SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP