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view test/compiler/6968348/Test6968348.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 | 52e82a6bedaf |
children |
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/* * Copyright (c) 2010, 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 6968348 * @summary Byteswapped memory access can point to wrong location after JIT * * @run main Test6968348 */ import sun.misc.Unsafe; import java.lang.reflect.*; public class Test6968348 { static Unsafe unsafe; static final long[] buffer = new long[4096]; static int array_long_base_offset; public static void main(String[] args) throws Exception { Class c = Test6968348.class.getClassLoader().loadClass("sun.misc.Unsafe"); Field f = c.getDeclaredField("theUnsafe"); f.setAccessible(true); unsafe = (Unsafe)f.get(c); array_long_base_offset = unsafe.arrayBaseOffset(long[].class); for (int n = 0; n < 100000; n++) { test(); } } public static void test() { for (long i = array_long_base_offset; i < 4096; i += 8) { unsafe.putLong(buffer, i, Long.reverseBytes(i)); } } }