Mercurial > hg > truffle
view test/compiler/7190310/Test7190310.java @ 11825:463f51256c86
AMD64HotSpot: emit jump to IC miss handler directly instead of emitting it inside verfied_entry
for empty methods we emitted something like this if a inline cache is needed:
prefix:
00: < IC check >
...
0b: jne <ic_miss_call>
11: nop
...
verified_entry:
20: ret
ic_miss_call:
21: jmp <entry of runtime function>
when a method is deoptimized, HotSpot patches the verified_entry (0x20) with a
jump to a stub that handles call-sites that has been made non-entrant. since this jump
is 5 bytes long, it will overwrite ic_miss_call and blow up every caller that
calls this method via the unverified entry (prefix).
the fix is to emit the jump to the runtime function inside the unverfied entry:
prefix:
00: < IC check >
...
0b: je <verified_entry>
11: jeq <entry of runtime function>
16: nop
...
verified_entry:
20: ret
author | Bernhard Urban <bernhard.urban@jku.at> |
---|---|
date | Mon, 30 Sep 2013 09:32:18 +0200 |
parents | bf623b2d5508 |
children |
line wrap: on
line source
/* * Copyright (c) 2012, 2013, 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. * */ /* * @test * @bug 7190310 * @summary Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops * @run main/othervm/timeout=600 -Xbatch Test7190310 */ /* * Note bug exhibits as infinite loop, timeout is helpful. * It should normally finish pretty quickly, but on some especially slow machines * it may not. The companion _unsafe test lacks a timeout, but that is okay. */ 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(); } }