Mercurial > hg > truffle
view test/compiler/7190310/Test7190310.java @ 6615:09aad8452938
7190310: Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops
Summary: In C2 add software membar after load from Reference.referent field to prevent commoning of loads across safepoint since GC can change its value. In C1 always generate Reference.get() intrinsic.
Reviewed-by: roland, twisti, dholmes, johnc
author | kvn |
---|---|
date | Mon, 20 Aug 2012 09:58:58 -0700 |
parents | |
children | bf623b2d5508 |
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/* * Copyright (c) 2012, 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. * */ /* * Manual test */ import java.lang.ref.*; public class Test7190310 { private static Object str = new Object() { public String toString() { return "The Object"; } protected void finalize() throws Throwable { System.out.println("The Object is being finalized"); super.finalize(); } }; private final static ReferenceQueue<Object> rq = new ReferenceQueue<Object>(); private final static WeakReference<Object> wr = new WeakReference<Object>(str, rq); public static void main(String[] args) throws InterruptedException { Thread reader = new Thread() { public void run() { while (wr.get() != null) { } System.out.println("wr.get() returned null"); } }; Thread queueReader = new Thread() { public void run() { try { Reference<? extends Object> ref = rq.remove(); System.out.println(ref); System.out.println("queueReader returned, ref==wr is " + (ref == wr)); } catch (InterruptedException e) { System.err.println("Sleep interrupted - exiting"); } } }; reader.start(); queueReader.start(); Thread.sleep(1000); str = null; System.gc(); } }