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 package art;
18 
19 import java.util.Arrays;
20 import java.lang.reflect.Executable;
21 import java.lang.reflect.Method;
22 import java.util.concurrent.Semaphore;
23 
24 public class Test1941 {
25   public static final boolean PRINT_CNT = false;
26   public static long CNT = 0;
27   public static final long MAX_ITERS = 100_000;
28 
29   // Method with multiple paths we can break on.
fib(long f)30   public static long fib(long f) {
31     if (f < 0) {
32       throw new IllegalArgumentException("Bad argument f < 0: f = " + f);
33     } else if (f == 0) {
34       return 0;
35     } else if (f == 1) {
36       return 1;
37     } else {
38       return fib(f - 1) + fib(f - 2);
39     }
40   }
41 
notifySingleStep(Thread thr, Executable e, long loc)42   public static void notifySingleStep(Thread thr, Executable e, long loc) {
43     // Don't bother actually doing anything.
44   }
45 
LoopAllocFreeEnv(Semaphore sem, Semaphore delay)46   public static void LoopAllocFreeEnv(Semaphore sem, Semaphore delay) {
47     sem.release();
48     try {
49       delay.acquire();
50     } catch (Exception e) {
51       throw new Error("exception occurred!", e);
52     }
53     while (!Thread.interrupted() && CNT < MAX_ITERS) {
54       CNT++;
55       long env = AllocEnv();
56       FreeEnv(env);
57       Thread.yield();
58     }
59   }
60 
AllocEnv()61   public static native long AllocEnv();
FreeEnv(long env)62   public static native void FreeEnv(long env);
63 
setTracingOn(Thread thr, boolean enable)64   public static native void setTracingOn(Thread thr, boolean enable);
65 
run()66   public static void run() throws Exception {
67     final Semaphore sem = new Semaphore(0);
68     final Semaphore delay = new Semaphore(0);
69     Thread thr = new Thread(() -> { LoopAllocFreeEnv(sem, delay); }, "LoopNative");
70     thr.start();
71     // Make sure the other thread is actually started.
72     sem.acquire();
73     Trace.enableSingleStepTracing(Test1941.class,
74         Test1941.class.getDeclaredMethod(
75             "notifySingleStep", Thread.class, Executable.class, Long.TYPE),
76         thr);
77     setTracingOn(Thread.currentThread(), true);
78     // Don't let the other thread start actually running until we've started
79     // tracing this thread too in order to ensure that the (formerly) racy
80     // behavior can happen.
81     delay.release();
82 
83     System.out.println("fib(20) is " + fib(20));
84 
85     thr.interrupt();
86     thr.join();
87     setTracingOn(Thread.currentThread(), false);
88     Trace.disableTracing(null);
89     if (PRINT_CNT) {
90       System.out.println("Number of envs created/destroyed: " + CNT);
91     }
92   }
93 }
94