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view test/compiler/6636138/Test2.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 | 7369298bec7e |
children | de6a9e811145 |
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/* * Copyright (c) 2009, 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 6636138 * @summary SuperWord::co_locate_pack(Node_List* p) generates memory graph that leads to memory order violation. * * @run main/othervm -Xbatch -XX:CompileOnly=Test2.shift Test2 */ public class Test2 { public static void init(int src[]) { // Initialize the array for (int i = 0; i < src.length; i++) src[i] = i; } public static void shift(int src[]) { //left-shift the array for (int i = src.length-1; i > 0; i--){ int tmp = src[i]; src[i] = src[i-1]; src[i-1] = tmp; } } public static void verify(int src[]) { for (int i = 0; i < src.length; i++){ int value = (i-1 + src.length)%src.length; // correct value after shifting if (src[i] != value) { System.out.println("Error: src["+i+"] should be "+ value + " instead of " + src[i]); System.exit(97); } } } public static void test() { int[] src = new int[10]; init(src); shift(src); verify(src); } public static void main(String[] args) { for (int i=0; i< 2000; i++) test(); } }