1 /*
2  * Copyright (C) 2018 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 import java.lang.invoke.MethodHandle;
18 import java.lang.invoke.MethodHandles;
19 import java.lang.invoke.MethodType;
20 import java.lang.invoke.VarHandle;
21 import java.lang.reflect.InvocationTargetException;
22 import java.lang.reflect.Method;
23 
24 public class Main {
25     private static final int ITERATIONS = 100;
26 
27     private static final VarHandle widgetIdVarHandle;
28 
getHotnessCounter(Class<?> cls, String methodName)29     public static native int getHotnessCounter(Class<?> cls, String methodName);
30 
31     public static class Widget {
Widget(int id)32         public Widget(int id) {
33             this.id = id;
34         }
35 
getId()36         int getId() {
37             return id;
38         }
39 
40         int id;
41     }
42 
43     static {
44         try {
45             widgetIdVarHandle = MethodHandles.lookup().findVarHandle(Widget.class, "id", int.class);
46         } catch (Exception e) {
47             throw new Error(e);
48         }
49     }
50 
assertEquals(int i1, int i2)51     private static void assertEquals(int i1, int i2) {
52         if (i1 == i2) {
53             return;
54         }
55         throw new AssertionError("assertEquals i1: " + i1 + ", i2: " + i2);
56     }
57 
assertEquals(Object o, Object p)58     private static void assertEquals(Object o, Object p) {
59         if (o == p) {
60             return;
61         }
62         if (o != null && p != null && o.equals(p)) {
63             return;
64         }
65         throw new AssertionError("assertEquals: o1: " + o + ", o2: " + p);
66     }
67 
fail()68     private static void fail() {
69         System.out.println("fail");
70         Thread.dumpStack();
71     }
72 
fail(String message)73     private static void fail(String message) {
74         System.out.println("fail: " + message);
75         Thread.dumpStack();
76     }
77 
testMethodHandleCounters()78     private static void testMethodHandleCounters() throws Throwable {
79         for (int i = 0; i < ITERATIONS; ++i) {
80             // Regular MethodHandle invocations
81             MethodHandle mh =
82                     MethodHandles.lookup()
83                             .findConstructor(
84                                     Widget.class, MethodType.methodType(void.class, int.class));
85             Widget w = (Widget) mh.invoke(3);
86             w = (Widget) mh.invokeExact(3);
87             assertEquals(0, getHotnessCounter(MethodHandle.class, "invoke"));
88             assertEquals(0, getHotnessCounter(MethodHandle.class, "invokeExact"));
89 
90             // Reflective MethodHandle invocations
91             String[] methodNames = {"invoke", "invokeExact"};
92             for (String methodName : methodNames) {
93                 Method invokeMethod = MethodHandle.class.getMethod(methodName, Object[].class);
94                 MethodHandle instance =
95                         MethodHandles.lookup()
96                                 .findVirtual(
97                                         Widget.class, "getId", MethodType.methodType(int.class));
98                 try {
99                     invokeMethod.invoke(instance, new Object[] {new Object[] {}});
100                     fail();
101                 } catch (InvocationTargetException ite) {
102                     assertEquals(ite.getCause().getClass(), UnsupportedOperationException.class);
103                 }
104             }
105             assertEquals(0, getHotnessCounter(MethodHandle.class, "invoke"));
106             assertEquals(0, getHotnessCounter(MethodHandle.class, "invokeExact"));
107         }
108 
109         System.out.println("MethodHandle OK");
110     }
111 
testVarHandleCounters()112     private static void testVarHandleCounters() throws Throwable {
113         Widget w = new Widget(0);
114         for (int i = 0; i < ITERATIONS; ++i) {
115             // Regular accessor invocations
116             widgetIdVarHandle.set(w, i);
117             assertEquals(i, widgetIdVarHandle.get(w));
118             assertEquals(0, getHotnessCounter(VarHandle.class, "set"));
119             assertEquals(0, getHotnessCounter(VarHandle.class, "get"));
120 
121             // Reflective accessor invocations
122             for (String accessorName : new String[] {"get", "set"}) {
123                 Method setMethod = VarHandle.class.getMethod(accessorName, Object[].class);
124                 try {
125                     setMethod.invoke(widgetIdVarHandle, new Object[] {new Object[0]});
126                     fail();
127                 } catch (InvocationTargetException ite) {
128                     assertEquals(ite.getCause().getClass(), UnsupportedOperationException.class);
129                 }
130             }
131             assertEquals(0, getHotnessCounter(VarHandle.class, "set"));
132             assertEquals(0, getHotnessCounter(VarHandle.class, "get"));
133         }
134         System.out.println("VarHandle OK");
135     }
136 
main(String[] args)137     public static void main(String[] args) throws Throwable {
138         System.loadLibrary(args[0]);
139         testMethodHandleCounters();
140         testVarHandleCounters();
141     }
142 }
143