8262122: [TESTBUG] Shenandoah-specific variant of TestReferenceRefersTo

Reviewed-by: shade

test/hotspot/jtreg/gc/shenandoah/TestReferenceRefersToShenandoah.java

@@ -0,0 +1,325 @@
+/*
+ * Copyright (c) 2020, 2021 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.
+ */
+
+package gc.shenandoah;
+
+/* @test
+ * @requires vm.gc.Shenandoah
+ * @library /test/lib
+ * @build sun.hotspot.WhiteBox
+ * @modules java.base
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run main/othervm
+ *      -Xbootclasspath/a:.
+ *      -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
+ *      -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=satb
+ *      gc.shenandoah.TestReferenceRefersToShenandoah
+ */
+
+/* @test
+ * @requires vm.gc.Shenandoah
+ * @library /test/lib
+ * @build sun.hotspot.WhiteBox
+ * @modules java.base
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run main/othervm
+ *      -Xbootclasspath/a:.
+ *      -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
+ *      -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=iu
+ *      gc.shenandoah.TestReferenceRefersToShenandoah
+ */
+
+import java.lang.ref.PhantomReference;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import sun.hotspot.WhiteBox;
+
+public class TestReferenceRefersToShenandoah {
+    private static final WhiteBox WB = WhiteBox.getWhiteBox();
+
+    private static final class TestObject {
+        public final int value;
+
+        public TestObject(int value) {
+            this.value = value;
+        }
+    }
+
+    private static volatile TestObject testObjectNone = null;
+    private static volatile TestObject testObject1 = null;
+    private static volatile TestObject testObject2 = null;
+    private static volatile TestObject testObject3 = null;
+    private static volatile TestObject testObject4 = null;
+
+    private static ReferenceQueue<TestObject> queue = null;
+
+    private static PhantomReference<TestObject> testPhantom1 = null;
+
+    private static WeakReference<TestObject> testWeak2 = null;
+    private static WeakReference<TestObject> testWeak3 = null;
+    private static WeakReference<TestObject> testWeak4 = null;
+
+    private static void setup() {
+        testObjectNone = new TestObject(0);
+        testObject1 = new TestObject(1);
+        testObject2 = new TestObject(2);
+        testObject3 = new TestObject(3);
+        testObject4 = new TestObject(4);
+
+        queue = new ReferenceQueue<TestObject>();
+
+        testPhantom1 = new PhantomReference<TestObject>(testObject1, queue);
+
+        testWeak2 = new WeakReference<TestObject>(testObject2, queue);
+        testWeak3 = new WeakReference<TestObject>(testObject3, queue);
+        testWeak4 = new WeakReference<TestObject>(testObject4, queue);
+    }
+
+    private static void gcUntilOld(Object o) throws Exception {
+        if (!WB.isObjectInOldGen(o)) {
+            WB.fullGC();
+            if (!WB.isObjectInOldGen(o)) {
+                fail("object not promoted by full gc");
+            }
+        }
+    }
+
+    private static void gcUntilOld() throws Exception {
+        gcUntilOld(testObjectNone);
+        gcUntilOld(testObject1);
+        gcUntilOld(testObject2);
+        gcUntilOld(testObject3);
+        gcUntilOld(testObject4);
+
+        gcUntilOld(testPhantom1);
+
+        gcUntilOld(testWeak2);
+        gcUntilOld(testWeak3);
+        gcUntilOld(testWeak4);
+    }
+
+    private static void progress(String msg) {
+        System.out.println(msg);
+    }
+
+    private static void fail(String msg) throws Exception {
+        throw new RuntimeException(msg);
+    }
+
+    private static void expectCleared(Reference<TestObject> ref,
+                                      String which) throws Exception {
+        expectNotValue(ref, testObjectNone, which);
+        if (!ref.refersTo(null)) {
+            fail("expected " + which + " to be cleared");
+        }
+    }
+
+    private static void expectNotCleared(Reference<TestObject> ref,
+                                         String which) throws Exception {
+        expectNotValue(ref, testObjectNone, which);
+        if (ref.refersTo(null)) {
+            fail("expected " + which + " to not be cleared");
+        }
+    }
+
+    private static void expectValue(Reference<TestObject> ref,
+                                    TestObject value,
+                                    String which) throws Exception {
+        expectNotValue(ref, testObjectNone, which);
+        expectNotCleared(ref, which);
+        if (!ref.refersTo(value)) {
+            fail(which + " doesn't refer to expected value");
+        }
+    }
+
+    private static void expectNotValue(Reference<TestObject> ref,
+                                       TestObject value,
+                                       String which) throws Exception {
+        if (ref.refersTo(value)) {
+            fail(which + " refers to unexpected value");
+        }
+    }
+
+    private static void checkInitialStates() throws Exception {
+        expectValue(testPhantom1, testObject1, "testPhantom1");
+        expectValue(testWeak2, testObject2, "testWeak2");
+        expectValue(testWeak3, testObject3, "testWeak3");
+        expectValue(testWeak4, testObject4, "testWeak4");
+    }
+
+    private static void discardStrongReferences() {
+        // testObjectNone not dropped
+        testObject1 = null;
+        testObject2 = null;
+        // testObject3 not dropped
+        testObject4 = null;
+    }
+
+    private static boolean isShenandoahIUMode() {
+        return "iu".equals(WB.getStringVMFlag("ShenandoahGCMode"));
+    }
+
+    private static void testConcurrentCollection() throws Exception {
+        progress("setup concurrent collection test");
+        setup();
+        progress("gcUntilOld");
+        gcUntilOld();
+
+        progress("acquire control of concurrent cycles");
+        WB.concurrentGCAcquireControl();
+        try {
+            progress("check initial states");
+            checkInitialStates();
+
+            progress("discard strong references");
+            discardStrongReferences();
+
+            progress("run GC to before marking completed");
+            WB.concurrentGCRunTo(WB.BEFORE_MARKING_COMPLETED);
+
+            progress("fetch test objects, possibly keeping some alive");
+            expectNotCleared(testPhantom1, "testPhantom1");
+            expectNotCleared(testWeak2, "testWeak2");
+            expectValue(testWeak3, testObject3, "testWeak3");
+
+            // For some collectors, calling get() will keep testObject4 alive.
+            if (testWeak4.get() == null) {
+                fail("testWeak4 unexpectedly == null");
+            }
+
+            progress("finish collection");
+            WB.concurrentGCRunToIdle();
+
+            progress("verify expected clears");
+            expectCleared(testPhantom1, "testPhantom1");
+            expectCleared(testWeak2, "testWeak2");
+            expectValue(testWeak3, testObject3, "testWeak3");
+            // This is true for all currently supported concurrent collectors,
+            // except Shenandoah+IU, which allows clearing refs even when
+            // accessed during concurrent marking.
+            if (isShenandoahIUMode()) {
+              expectCleared(testWeak4, "testWeak4");
+            } else {
+              expectNotCleared(testWeak4, "testWeak4");
+            }
+
+            progress("verify get returns expected values");
+            if (testWeak2.get() != null) {
+                fail("testWeak2.get() != null");
+            }
+
+            TestObject obj3 = testWeak3.get();
+            if (obj3 == null) {
+                fail("testWeak3.get() returned null");
+            } else if (obj3.value != 3) {
+                fail("testWeak3.get().value is " + obj3.value);
+            }
+
+            TestObject obj4 = testWeak4.get();
+            if (!isShenandoahIUMode()) {
+                if (obj4 == null) {
+                    fail("testWeak4.get() returned null");
+                } else if (obj4.value != 4) {
+                    fail("testWeak4.get().value is " + obj4.value);
+                }
+            }
+
+            progress("verify queue entries");
+            long timeout = 60000; // 1 minute of milliseconds.
+            while (true) {
+                Reference<? extends TestObject> ref = queue.remove(timeout);
+                if (ref == null) {
+                    break;
+                } else if (ref == testPhantom1) {
+                    testPhantom1 = null;
+                } else if (ref == testWeak2) {
+                    testWeak2 = null;
+                } else if (ref == testWeak3) {
+                    testWeak3 = null;
+                } else if (ref == testWeak4) {
+                    testWeak4 = null;
+                } else {
+                    fail("unexpected reference in queue");
+                }
+            }
+            if (testPhantom1 != null) {
+                fail("testPhantom1 not notified");
+            } else if (testWeak2 != null) {
+                fail("testWeak2 not notified");
+            } else if (testWeak3 == null) {
+                fail("testWeak3 notified");
+            } else if (testWeak4 == null) {
+                if (obj4 != null) {
+                    fail("testWeak4 notified");
+                }
+            }
+
+        } finally {
+            progress("release control of concurrent cycles");
+            WB.concurrentGCReleaseControl();
+        }
+        progress("finished concurrent collection test");
+    }
+
+    private static void testSimpleCollection() throws Exception {
+        progress("setup simple collection test");
+        setup();
+        progress("gcUntilOld");
+        gcUntilOld();
+
+        progress("check initial states");
+        checkInitialStates();
+
+        progress("discard strong references");
+        TestObject tw4 = testWeak4.get(); // Keep testObject4 alive.
+        discardStrongReferences();
+
+        progress("collect garbage");
+        WB.fullGC();
+
+        progress("verify expected clears");
+        expectCleared(testPhantom1, "testPhantom1");
+        expectCleared(testWeak2, "testWeak2");
+        expectValue(testWeak3, testObject3, "testWeak3");
+        expectNotCleared(testWeak4, "testWeak4");
+
+        progress("verify get returns expected values");
+        if (testWeak2.get() != null) {
+            fail("testWeak2.get() != null");
+        } else if (testWeak3.get() != testObject3) {
+            fail("testWeak3.get() is not expected value");
+        } else if (testWeak4.get() != tw4) {
+            fail("testWeak4.get() is not expected value");
+        }
+
+        progress("finished simple collection test");
+    }
+
+    public static void main(String[] args) throws Exception {
+        if (WB.supportsConcurrentGCBreakpoints()) {
+            testConcurrentCollection();
+        }
+        testSimpleCollection();
+    }
+}