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view test/compiler/7179138/Test7179138_1.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 | 751bd303aa45 |
children |
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/* * Copyright 2012 Skip Balk. 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 7179138 * @summary Incorrect result with String concatenation optimization * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:-TieredCompilation Test7179138_1 * * @author Skip Balk */ public class Test7179138_1 { public static void main(String[] args) throws Exception { System.out.println("Java Version: " + System.getProperty("java.vm.version")); long[] durations = new long[60]; for (int i = 0; i < 100000; i++) { // this empty for-loop is required to reproduce this bug for (long duration : durations) { // do nothing } { String s = "test"; int len = s.length(); s = new StringBuilder(String.valueOf(s)).append(s).toString(); len = len + len; s = new StringBuilder(String.valueOf(s)).append(s).toString(); len = len + len; s = new StringBuilder(String.valueOf(s)).append(s).toString(); len = len + len; if (s.length() != len) { System.out.println("Failed at iteration: " + i); System.out.println("Length mismatch: " + s.length() + " <> " + len); System.out.println("Expected: \"" + "test" + "test" + "test" + "test" + "test" + "test" + "test" + "test" + "\""); System.out.println("Actual: \"" + s + "\""); System.exit(97); } } } } }