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/*
* Copyright (c) 2015, 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 8133348
* @summary Tests if reachabilityFence is working
*
* @run main/othervm -Xint -Dpremature=false ReachabilityFenceTest
* @run main/othervm -XX:TieredStopAtLevel=1 -Dpremature=true ReachabilityFenceTest
* @run main/othervm -XX:TieredStopAtLevel=2 -Dpremature=true ReachabilityFenceTest
* @run main/othervm -XX:TieredStopAtLevel=3 -Dpremature=true ReachabilityFenceTest
* @run main/othervm -XX:TieredStopAtLevel=4 -Dpremature=true ReachabilityFenceTest
*/
import java.lang.ref.Reference;
import java.util.concurrent.atomic.AtomicBoolean;
public class ReachabilityFenceTest {
/*
* Implementation notes:
*
* This test has positive and negative parts.
*
* Negative test is "nonFenced", and it tests that absent of reachabilityFence, the object can
* be prematurely finalized -- this validates the test itself. Not every VM mode is expected to
* prematurely finalize the objects, and -Dpremature option communicates that to test. If a VM mode
* passes the negative test, then our understanding of what could happen is correct, and we can
* go forward.
*
* Positive test is "fenced", and it checks that given the reachabilityFence at the end of the block,
* the object cannot be finalized. There is no sense running a positive test when premature finalization
* is not expected. It is a job for negative test to verify that invariant.
*
* The test methods should be appropriately compiled, therefore we do several iterations.
*/
// Enough to OSR and compile
static final int LOOP_ITERS = Integer.getInteger("LOOP_ITERS", 50000);
// Enough after which to start triggering GC and finalization
static final int WARMUP_LOOP_ITERS = LOOP_ITERS - Integer.getInteger("GC_ITERS", 100);
// Enough to switch from an OSR'ed method to compiled method
static final int MAIN_ITERS = 3;
static final boolean PREMATURE_FINALIZATION = Boolean.getBoolean("premature");
public static void main(String... args) {
// Negative test
boolean finalized = false;
for (int c = 0; !finalized && c < MAIN_ITERS; c++) {
finalized |= nonFenced();
}
if (PREMATURE_FINALIZATION && !finalized) {
throw new IllegalStateException("The object had never been finalized before timeout reached.");
}
if (!PREMATURE_FINALIZATION && finalized) {
throw new IllegalStateException("The object had been finalized without a fence, even though we don't expect it.");
}
if (!PREMATURE_FINALIZATION)
return;
// Positive test
finalized = false;
for (int c = 0; !finalized && c < MAIN_ITERS; c++) {
finalized |= fenced();
}
if (finalized) {
throw new IllegalStateException("The object had been prematurely finalized.");
}
}
public static boolean nonFenced() {
AtomicBoolean finalized = new AtomicBoolean();
MyFinalizeable o = new MyFinalizeable(finalized);
for (int i = 0; i < LOOP_ITERS; i++) {
if (finalized.get()) break;
if (i > WARMUP_LOOP_ITERS) {
System.gc();
System.runFinalization();
}
}
return finalized.get();
}
public static boolean fenced() {
AtomicBoolean finalized = new AtomicBoolean();
MyFinalizeable o = new MyFinalizeable(finalized);
for (int i = 0; i < LOOP_ITERS; i++) {
if (finalized.get()) break;
if (i > WARMUP_LOOP_ITERS) {
System.gc();
System.runFinalization();
}
}
try {
return finalized.get();
} finally {
Reference.reachabilityFence(o);
}
}
private static class MyFinalizeable {
private final AtomicBoolean finalized;
public MyFinalizeable(AtomicBoolean b) {
this.finalized = b;
}
@Override
protected void finalize() throws Throwable {
super.finalize();
finalized.set(true);
}
}
}
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