1 /*
  2  * Copyright (c) 2018, 2026, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  */
 23 
 24 
 25 /*
 26  * @test
 27  * @summary test VarHandle on value class array
 28  * @enablePreview
 29  * @run junit/othervm -XX:+UseArrayFlattening ArrayElementVarHandleTest
 30  * @run junit/othervm -XX:-UseArrayFlattening  ArrayElementVarHandleTest
 31  */
 32 
 33 import java.lang.invoke.*;
 34 import java.util.stream.Stream;
 35 
 36 import jdk.internal.vm.annotation.NullRestricted;
 37 import org.junit.jupiter.params.ParameterizedTest;
 38 import org.junit.jupiter.params.provider.Arguments;
 39 import org.junit.jupiter.params.provider.MethodSource;
 40 import static org.junit.jupiter.api.Assertions.*;
 41 
 42 public class ArrayElementVarHandleTest {
 43     static value class Point {
 44         public int x;
 45         public int y;
 46         Point(int x, int y) {
 47             this.x = x;
 48             this.y = y;
 49         }
 50     }
 51 
 52     static value class Line {
 53         @NullRestricted
 54         Point p1;
 55         @NullRestricted
 56         Point p2;
 57 
 58         Line(Point p1, Point p2) {
 59             this.p1 = p1;
 60             this.p2 = p2;
 61         }
 62         Line(int x1, int y1, int x2, int y2) {
 63             this(new Point(x1, y1), new Point(x2, y2));
 64         }
 65     }
 66 
 67     private static final Point[] POINTS = new Point[]{
 68             new Point(1, 2),
 69             new Point(10, 20),
 70             new Point(100, 200),
 71             null
 72     };
 73 
 74     private static final Line[] LINES = new Line[]{
 75             new Line(1, 2, 3, 4),
 76             new Line(10, 20, 30, 40),
 77             null
 78     };
 79 
 80     static Stream<Arguments> testCases() throws Throwable {
 81         int plen = POINTS.length;
 82         int llen = LINES.length;
 83         return Stream.of(
 84                 Arguments.of(newArray(Object[].class, plen),    POINTS),
 85                 Arguments.of(newArray(Object[].class, plen),    new Object[] { "abc", new Point(1, 2) }),
 86                 Arguments.of(newArray(Point[].class, plen),     POINTS),
 87                 Arguments.of(new Point[plen],                   POINTS),
 88 
 89                 Arguments.of(newArray(Object[].class, llen),    LINES),
 90                 Arguments.of(newArray(Line[].class, llen),      LINES),
 91                 Arguments.of(new Line[llen],                    LINES)
 92         );
 93     }
 94 
 95     /*
 96      * Constructs a new array of the specified type and size using
 97      * MethodHandle.
 98      */
 99     private static Object[] newArray(Class<?> arrayType, int size) throws Throwable {
100         MethodHandle ctor = MethodHandles.arrayConstructor(arrayType);
101         return (Object[]) ctor.invoke(size);
102     }
103 
104     /*
105      * Test VarHandle to set elements of the given array with
106      * various access mode.
107      */
108     @ParameterizedTest
109     @MethodSource("testCases")
110     public void testSetArrayElements(Object[] array, Object[] elements) {
111         Class<?> arrayType = array.getClass();
112         assertTrue(array.length >= elements.length);
113 
114         VarHandle vh = MethodHandles.arrayElementVarHandle(arrayType);
115         set(vh, array.clone(), elements);
116         setVolatile(vh, array.clone(), elements);
117         setOpaque(vh, array.clone(), elements);
118         setRelease(vh, array.clone(), elements);
119         getAndSet(vh, array.clone(), elements);
120         compareAndSet(vh, array.clone(), elements);
121         compareAndExchange(vh, array.clone(), elements);
122     }
123 
124     // VarHandle::set
125     void set(VarHandle vh, Object[] array, Object[] elements) {
126         for (int i = 0; i < elements.length; i++) {
127             vh.set(array, i, elements[i]);
128         }
129         for (int i = 0; i < elements.length; i++) {
130             Object v = (Object) vh.get(array, i);
131             assertEquals(elements[i], v);
132         }
133     }
134 
135     // VarHandle::setVolatile
136     void setVolatile(VarHandle vh, Object[] array, Object[] elements) {
137         for (int i = 0; i < elements.length; i++) {
138             vh.setVolatile(array, i, elements[i]);
139         }
140         for (int i = 0; i < elements.length; i++) {
141             Object v = (Object) vh.getVolatile(array, i);
142             assertEquals(elements[i], v);
143         }
144     }
145 
146     // VarHandle::setOpaque
147     void setOpaque(VarHandle vh, Object[] array, Object[] elements) {
148         for (int i = 0; i < elements.length; i++) {
149             vh.setOpaque(array, i, elements[i]);
150         }
151         for (int i = 0; i < elements.length; i++) {
152             Object v = (Object) vh.getOpaque(array, i);
153             assertEquals(elements[i], v);
154         }
155     }
156 
157     // VarHandle::setRelease
158     void setRelease(VarHandle vh, Object[] array, Object[] elements) {
159         for (int i = 0; i < elements.length; i++) {
160             vh.setRelease(array, i, elements[i]);
161         }
162         for (int i = 0; i < elements.length; i++) {
163             Object v = (Object) vh.getAcquire(array, i);
164             assertEquals(elements[i], v);
165         }
166     }
167 
168     void getAndSet(VarHandle vh, Object[] array, Object[] elements) {
169         for (int i = 0; i < elements.length; i++) {
170             Object o = vh.getAndSet(array, i, elements[i]);
171         }
172         for (int i = 0; i < elements.length; i++) {
173             Object v = (Object) vh.get(array, i);
174             assertEquals(elements[i], v);
175         }
176     }
177 
178     // sanity CAS test
179     // see test/jdk/java/lang/invoke/VarHandles tests
180     void compareAndSet(VarHandle vh, Object[] array, Object[] elements) {
181         // initialize to some values
182         for (int i = 0; i < elements.length; i++) {
183             vh.set(array, i, elements[i]);
184         }
185         // shift to the right element
186         for (int i = 0; i < elements.length; i++) {
187             Object v = elements[i + 1 < elements.length ? i + 1 : 0];
188             boolean cas = vh.compareAndSet(array, i, elements[i], v);
189             if (!cas)
190                 System.out.format("cas = %s array[%d] = %s vs old = %s new = %s%n", cas, i, array[i], elements[i], v);
191             assertTrue(cas);
192         }
193     }
194 
195     void compareAndExchange(VarHandle vh, Object[] array, Object[] elements) {
196         // initialize to some values
197         for (int i = 0; i < elements.length; i++) {
198             vh.set(array, i, elements[i]);
199         }
200         // shift to the right element
201         for (int i = 0; i < elements.length; i++) {
202             Object v = elements[i + 1 < elements.length ? i + 1 : 0];
203             assertEquals(elements[i], vh.compareAndExchange(array, i, elements[i], v));
204         }
205     }
206 }