jdk-24/test/hotspot/jtreg/compiler/c2/Test7190310_unsafe.java

/*
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 * 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.
 *
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 */

/*
 * @test
 * @bug 7190310
 * @summary Inlining WeakReference.get(), and hoisting $referent may lead to non-terminating loops
 * @modules java.base/jdk.internal.misc:+open
 * @modules java.base/java.lang.ref:open
 *
 * @run main/othervm -Xbatch compiler.c2.Test7190310_unsafe
 */

package compiler.c2;

import jdk.internal.misc.Unsafe;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;

public class Test7190310_unsafe {

    static class TestObject {
        public String toString() {
            return "TestObject";
        }
    }

    ;

    private static TestObject str = new TestObject();
    private static final WeakReference ref = new WeakReference(str);

    private TestObject obj;

    public static void main(String[] args) throws Exception {
        Class c = Test7190310_unsafe.class.getClassLoader().loadClass("jdk.internal.misc.Unsafe");
        Field f = c.getDeclaredField("theUnsafe");
        f.setAccessible(true);
        Unsafe unsafe = (Unsafe) f.get(c);

        f = Reference.class.getDeclaredField("referent");
        f.setAccessible(true);
        long referent_offset = unsafe.objectFieldOffset(f);

        Test7190310_unsafe t = new Test7190310_unsafe();
        TestObject o = new TestObject();
        t.obj = o;

        // Warmup (compile methods)
        System.err.println("Warmup");
        Object obj = null;
        for (int i = 0; i < 11000; i++) {
            obj = getRef0(ref);
        }
        for (int i = 0; i < 11000; i++) {
            obj = getRef1(unsafe, ref, referent_offset);
        }
        for (int i = 0; i < 11000; i++) {
            obj = getRef2(unsafe, ref, referent_offset);
        }
        for (int i = 0; i < 11000; i++) {
            obj = getRef3(unsafe, ref, referent_offset);
        }
        for (int i = 0; i < 11000; i++) {
            obj = getRef4(unsafe, t, referent_offset);
        }

        // Access verification
        System.err.println("Verification");
        if (!verifyGet(referent_offset, unsafe)) {
            System.exit(97);
        }

        obj = getRef3(unsafe, t, referent_offset);
        if (obj != o) {
            System.out.println("FAILED: unsafe.getReference(Object, " + referent_offset + ") " + obj + " != " + o);
            System.exit(97);
        }
        obj = getRef4(unsafe, t, referent_offset);
        if (obj != o) {
            System.out.println("FAILED: unsafe.getReference(Test7190310, " + referent_offset + ") " + obj + " != " + o);
            System.exit(97);
        }
    }

    static boolean verifyGet(long referent_offset, Unsafe unsafe) throws Exception {
        // Access verification
        System.out.println("referent: " + str);
        Object obj = getRef0(ref);
        if (obj != str) {
            System.out.println("FAILED: weakRef.get() " + obj + " != " + str);
            return false;
        }
        obj = getRef1(unsafe, ref, referent_offset);
        if (obj != str) {
            System.out.println("FAILED: unsafe.getReference(weakRef, " + referent_offset + ") " + obj + " != " + str);
            return false;
        }
        obj = getRef2(unsafe, ref, referent_offset);
        if (obj != str) {
            System.out.println("FAILED: unsafe.getReference(abstRef, " + referent_offset + ") " + obj + " != " + str);
            return false;
        }
        obj = getRef3(unsafe, ref, referent_offset);
        if (obj != str) {
            System.out.println("FAILED: unsafe.getReference(Object, " + referent_offset + ") " + obj + " != " + str);
            return false;
        }
        return true;
    }

    static Object getRef0(WeakReference ref) throws Exception {
        return ref.get();
    }

    static Object getRef1(Unsafe unsafe, WeakReference ref, long referent_offset) throws Exception {
        return unsafe.getReference(ref, referent_offset);
    }

    static Object getRef2(Unsafe unsafe, Reference ref, long referent_offset) throws Exception {
        return unsafe.getReference(ref, referent_offset);
    }

    static Object getRef3(Unsafe unsafe, Object ref, long referent_offset) throws Exception {
        return unsafe.getReference(ref, referent_offset);
    }

    static Object getRef4(Unsafe unsafe, Test7190310_unsafe ref, long referent_offset) throws Exception {
        return unsafe.getReference(ref, referent_offset);
    }
}