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view test/compiler/6805724/Test6805724.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 | c18cbe5936b8 |
children |
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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 6805724 * @summary ModLNode::Ideal() generates functionally incorrect graph when divisor is any (2^k-1) constant. * * @run main/othervm -Xcomp -XX:CompileOnly=Test6805724.fcomp Test6805724 */ import java.net.URLClassLoader; public class Test6805724 implements Runnable { // Initialize DIVISOR so that it is final in this class. static final long DIVISOR; // 2^k-1 constant static { long value = 0; try { value = Long.decode(System.getProperty("divisor")); } catch (Throwable t) { // This one is required for the Class.forName() in main. } DIVISOR = value; } static long fint(long x) { return x % DIVISOR; } static long fcomp(long x) { return x % DIVISOR; } public void run() { long a = 0x617981E1L; long expected = fint(a); long result = fcomp(a); if (result != expected) throw new InternalError(result + " != " + expected); } public static void main(String args[]) throws Exception { Class cl = Class.forName("Test6805724"); URLClassLoader apploader = (URLClassLoader) cl.getClassLoader(); // Iterate over all 2^k-1 divisors. for (int k = 1; k < Long.SIZE; k++) { long divisor = (1L << k) - 1; System.setProperty("divisor", "" + divisor); ClassLoader loader = new URLClassLoader(apploader.getURLs(), apploader.getParent()); Class c = loader.loadClass("Test6805724"); Runnable r = (Runnable) c.newInstance(); r.run(); } } }