hotspot/src/os/posix/vm/threadLocalStorage_posix.cpp
changeset 34633 2a6c7c7b30a7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/os/posix/vm/threadLocalStorage_posix.cpp	Fri Dec 04 04:06:37 2015 -0500
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 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.
+ *
+ */
+
+#include "runtime/threadLocalStorage.hpp"
+#include <pthread.h>
+
+static pthread_key_t _thread_key;
+static bool _initialized = false;
+
+// Restore the thread pointer if the destructor is called. This is in case
+// someone from JNI code sets up a destructor with pthread_key_create to run
+// detachCurrentThread on thread death. Unless we restore the thread pointer we
+// will hang or crash. When detachCurrentThread is called the key will be set
+// to null and we will not be called again. If detachCurrentThread is never
+// called we could loop forever depending on the pthread implementation.
+extern "C" void restore_thread_pointer(void* p) {
+  ThreadLocalStorage::set_thread((Thread*) p);
+}
+
+void ThreadLocalStorage::init() {
+  assert(!_initialized, "initializing TLS more than once!");
+  int rslt = pthread_key_create(&_thread_key, restore_thread_pointer);
+  // If this assert fails we will get a recursive assertion failure
+  // and not see the actual error message or get a hs_err file
+  assert_status(rslt == 0, rslt, "pthread_key_create");
+  _initialized = true;
+}
+
+bool ThreadLocalStorage::is_initialized() {
+  return _initialized;
+}
+
+Thread* ThreadLocalStorage::thread() {
+  // If this assert fails we will get a recursive assertion failure
+  // and not see the actual error message or get a hs_err file.
+  // Which most likely indicates we have taken an error path early in
+  // the initialization process, which is using Thread::current without
+  // checking TLS is initialized - see java.cpp vm_exit
+  assert(_initialized, "TLS not initialized yet!");
+  return (Thread*) pthread_getspecific(_thread_key); // may be NULL
+}
+
+void ThreadLocalStorage::set_thread(Thread* current) {
+  assert(_initialized, "TLS not initialized yet!");
+  int rslt = pthread_setspecific(_thread_key, current);
+  assert_status(rslt == 0, rslt, "pthread_setspecific");
+}