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/*
* Copyright (c) 2017, 2018, Red Hat, Inc. 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 TestMaybeNullUnsafeAccess
* @summary cast before unsafe access moved in dominating null check null path causes crash
* @key gc
* @requires vm.gc.Shenandoah & !vm.graal.enabled
* @modules java.base/jdk.internal.misc:+open
*
* @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation
* TestMaybeNullUnsafeAccess
*
* @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation -XX:-TieredCompilation
* -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC
* TestMaybeNullUnsafeAccess
*
*/
import jdk.internal.misc.Unsafe;
import java.lang.reflect.Field;
public class TestMaybeNullUnsafeAccess {
static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();
static final long F_OFFSET;
static class A {
int f;
}
static {
try {
Field fField = A.class.getDeclaredField("f");
F_OFFSET = UNSAFE.objectFieldOffset(fField);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
static A test_helper(Object o) {
return (A) o;
}
static int test(Object o) {
int f = 0;
for (int i = 0; i < 100; i++) {
A a = test_helper(o);
f = UNSAFE.getInt(a, F_OFFSET);
}
return f;
}
static public void main(String[] args) {
A a = new A();
for (int i = 0; i < 20000; i++) {
test_helper(null);
test_helper(a);
test(a);
}
}
}
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