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view test/compiler/5091921/Test6905845.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 | 514efad5e81a |
children |
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/* * Copyright (c) 2011, 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 6905845 * @summary Server VM improperly optimizing away loop. * * @run main/timeout=480 Test6905845 */ public class Test6905845 { public static void main(String[] args){ for (int asdf = 0; asdf < 5; asdf++){ //test block { StringBuilder strBuf1 = new StringBuilder(65); long start = System.currentTimeMillis(); int count = 0; for (int i = Integer.MIN_VALUE; i < (Integer.MAX_VALUE - 80); i += 79){ strBuf1.append(i); count++; strBuf1.delete(0, 65); } System.out.println(count); if (count != 54366674) { System.out.println("wrong count: " + count +", should be 54366674"); System.exit(97); } } //test block { StringBuilder strBuf1 = new StringBuilder(65); long start = System.currentTimeMillis(); int count = 0; for (int i = Integer.MIN_VALUE; i < (Integer.MAX_VALUE - 80); i += 79){ strBuf1.append(i); count++; strBuf1.delete(0, 65); } System.out.println(count); if (count != 54366674) { System.out.println("wrong count: " + count +", should be 54366674"); System.exit(97); } } } } }