test/616-cha-regression-proxy-method/src/Main.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

class Main1 {
    void foo(int i) {
        if (i != 1) {
            printError("error1");
        }
    }

    void printError(String msg) {
        System.out.println(msg);
    }
}

class Main2 extends Main1 {
    void foo(int i) {
        if (i != 2) {
            printError("error2");
        }
    }
}

class Proxied implements Runnable {
    public void run() {
        synchronized(Main.class) {
            Main.sOtherThreadStarted = true;
            // Wait for Main2 to be linked and deoptimization is triggered.
            try {
                Main.class.wait();
            } catch (Exception e) {
            }
        }
    }
}

class MyInvocationHandler implements InvocationHandler {
    private final Proxied proxied;

    public MyInvocationHandler(Proxied proxied) {
        this.proxied = proxied;
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        return method.invoke(proxied, args);
    }
}

public class Main {
    static Main1 sMain1;
    static Main1 sMain2;
    static volatile boolean sOtherThreadStarted;

    // sMain1.foo() will be always be Main1.foo() before Main2 is loaded/linked.
    // So sMain1.foo() can be devirtualized to Main1.foo() and be inlined.
    // After Helper.createMain2() which links in Main2, live testOverride() on stack
    // should be deoptimized.
    static void testOverride() {
        sMain1.foo(sMain1.getClass() == Main1.class ? 1 : 2);

        // Wait for the other thread to start.
        while (!sOtherThreadStarted);
        // Create an Main2 instance and assign it to sMain2.
        // sMain1 is kept the same.
        sMain2 = Helper.createMain2();
        // Wake up the other thread.
        synchronized(Main.class) {
            Main.class.notify();
        }

        // There should be a deoptimization here right after Main2 is linked by
        // calling Helper.createMain2(), even though sMain1 didn't change.
        // The behavior here would be different if inline-cache is used, which
        // doesn't deoptimize since sMain1 still hits the type cache.
        sMain1.foo(sMain1.getClass() == Main1.class ? 1 : 2);
        if (sMain2 != null) {
            sMain2.foo(sMain2.getClass() == Main1.class ? 1 : 2);
        }
    }

    // Test scenarios under which CHA-based devirtualization happens,
    // and class loading that overrides a method can invalidate compiled code.
    // Also create a proxy method such that a proxy method's frame is visited
    // during stack walking.
    public static void main(String[] args) {
        System.loadLibrary(args[0]);
        // sMain1 is an instance of Main1. Main2 hasn't bee loaded yet.
        sMain1 = new Main1();

        // Create another thread that calls a proxy method.
        new Thread() {
            public void run() {
                Runnable proxy = (Runnable)Proxy.newProxyInstance(
                        Proxied.class.getClassLoader(),
                        new Class[] { Runnable.class },
                        new MyInvocationHandler(new Proxied()));
                proxy.run();
            }
        }.start();

        ensureJitCompiled(Main.class, "testOverride");
        // This will create Main2 instance in the middle of testOverride().
        testOverride();
    }

    private static native void ensureJitCompiled(Class<?> itf, String method_name);
}

// Put createMain2() in another class to avoid class loading due to verifier.
class Helper {
    static Main1 createMain2() {
        return new Main2();
    }
}