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1 /*
2  * Copyright (C) 2017 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 interface Iface {
foo(int i)18     public void foo(int i);
19 }
20 
21 abstract class Base implements Iface {
22     // Iface.foo(int) will be added as a miranda method.
23 
printError(String msg)24     void printError(String msg) {
25         System.out.println(msg);
26     }
27 }
28 
29 class Main1 extends Base {
foo(int i)30     public void foo(int i) {
31         if (i != 1) {
32             printError("error1");
33         }
34     }
35 }
36 
37 class Main2 extends Main1 {
foo(int i)38     public void foo(int i) {
39         if (i != 2) {
40             printError("error2");
41         }
42     }
43 }
44 
45 public class Main {
46     static Base sMain1;
47     static Base sMain2;
48 
49     static boolean sIsOptimizing = true;
50     static boolean sHasJIT = true;
51     static volatile boolean sOtherThreadStarted;
52 
assertSingleImplementation(Class<?> clazz, String method_name, boolean b)53     private static void assertSingleImplementation(Class<?> clazz, String method_name, boolean b) {
54         if (hasSingleImplementation(clazz, method_name) != b) {
55             System.out.println(clazz + "." + method_name +
56                     " doesn't have single implementation value of " + b);
57         }
58     }
59 
60     // sMain1.foo() will be always be Main1.foo() before Main2 is loaded/linked.
61     // So sMain1.foo() can be devirtualized to Main1.foo() and be inlined.
62     // After Helper.createMain2() which links in Main2, live testOverride() on stack
63     // should be deoptimized.
testOverride(boolean createMain2, boolean wait)64     static void testOverride(boolean createMain2, boolean wait) {
65         if (createMain2 && (sIsOptimizing || sHasJIT)) {
66             assertIsManaged();
67         }
68 
69         sMain1.foo(sMain1.getClass() == Main1.class ? 1 : 2);
70 
71         if (createMain2) {
72             // Wait for the other thread to start.
73             while (!sOtherThreadStarted);
74             // Create an Main2 instance and assign it to sMain2.
75             // sMain1 is kept the same.
76             sMain2 = Helper.createMain2();
77             // Wake up the other thread.
78             synchronized(Main.class) {
79                 Main.class.notify();
80             }
81         } else if (wait) {
82             // This is the other thread.
83             synchronized(Main.class) {
84                 sOtherThreadStarted = true;
85                 // Wait for Main2 to be linked and deoptimization is triggered.
86                 try {
87                     Main.class.wait();
88                 } catch (Exception e) {
89                 }
90             }
91         }
92 
93         // There should be a deoptimization here right after Main2 is linked by
94         // calling Helper.createMain2(), even though sMain1 didn't change.
95         // The behavior here would be different if inline-cache is used, which
96         // doesn't deoptimize since sMain1 still hits the type cache.
97         sMain1.foo(sMain1.getClass() == Main1.class ? 1 : 2);
98         if ((createMain2 || wait) && sHasJIT && !sIsOptimizing) {
99             // This method should be deoptimized right after Main2 is created.
100             assertIsInterpreted();
101         }
102 
103         if (sMain2 != null) {
104             sMain2.foo(sMain2.getClass() == Main1.class ? 1 : 2);
105         }
106     }
107 
108     // Test scenarios under which CHA-based devirtualization happens,
109     // and class loading that overrides a method can invalidate compiled code.
main(String[] args)110     public static void main(String[] args) {
111         System.loadLibrary(args[0]);
112 
113         sIsOptimizing = isAotCompiled(Main.class, "testOverride");
114         sHasJIT = hasJit();
115 
116         // sMain1 is an instance of Main1. Main2 hasn't bee loaded yet.
117         sMain1 = new Main1();
118 
119         ensureJitCompiled(Main.class, "testOverride");
120 
121         if (sHasJIT && !sIsOptimizing) {
122             assertSingleImplementation(Base.class, "foo", true);
123             assertSingleImplementation(Main1.class, "foo", true);
124         } else {
125             // Main2 is verified ahead-of-time so it's linked in already.
126         }
127 
128         // Create another thread that also calls sMain1.foo().
129         // Try to test suspend and deopt another thread.
130         new Thread() {
131             public void run() {
132                 testOverride(false, true);
133             }
134         }.start();
135 
136         // This will create Main2 instance in the middle of testOverride().
137         testOverride(true, false);
138         assertSingleImplementation(Base.class, "foo", false);
139         assertSingleImplementation(Main1.class, "foo", false);
140     }
141 
hasJit()142     private static native boolean hasJit();
isAotCompiled(Class<?> cls, String methodName)143     private native static boolean isAotCompiled(Class<?> cls, String methodName);
ensureJitCompiled(Class<?> itf, String method_name)144     private static native void ensureJitCompiled(Class<?> itf, String method_name);
assertIsInterpreted()145     private static native void assertIsInterpreted();
assertIsManaged()146     private static native void assertIsManaged();
isInterpreted()147     private static native boolean isInterpreted();
hasSingleImplementation(Class<?> clazz, String method_name)148     private static native boolean hasSingleImplementation(Class<?> clazz, String method_name);
149 }
150 
151 // Put createMain2() in another class to avoid class loading due to verifier.
152 class Helper {
createMain2()153     static Main1 createMain2() {
154         return new Main2();
155     }
156 }
157