616-cha/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.
 */

class Main1 {
  String getName() {
    return "Main1";
  }

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

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

  int getValue1() {
    return 1;
  }
  int getValue2() {
    return 2;
  }
  int getValue3() {
    return 3;
  }
  int getValue4() {
    return 4;
  }
  int getValue5() {
    return 5;
  }
  int getValue6() {
    return 6;
  }
}

class Main2 extends Main1 {
  String getName() {
    return "Main2";
  }

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

class Main3 extends Main1 {
  String getName() {
    return "Main3";
  }
}

public class Main {
  static Main1 sMain1;
  static Main1 sMain2;

  static boolean sIsOptimizing = true;
  static boolean sHasJIT = true;
  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 Dummy.createMain2() which links in Main2, live testOverride() on stack
  // should be deoptimized.
  static void testOverride(boolean createMain2, boolean wait, boolean setHasJIT) {
    if (setHasJIT) {
      if (isInterpreted()) {
        sHasJIT = false;
      }
      return;
    }

    if (createMain2 && (sIsOptimizing || sHasJIT)) {
      assertIsManaged();
    }

    sMain1.foo(sMain1.getClass() == Main1.class ? 1 : 2);

    if (createMain2) {
      // Wait for the other thread to start.
      while (!sOtherThreadStarted);
      // Create an Main2 instance and assign it to sMain2.
      // sMain1 is kept the same.
      sMain2 = Dummy.createMain2();
      // Wake up the other thread.
      synchronized(Main.class) {
        Main.class.notify();
      }
    } else if (wait) {
      // This is the other thread.
      synchronized(Main.class) {
        sOtherThreadStarted = true;
        // Wait for Main2 to be linked and deoptimization is triggered.
        try {
          Main.class.wait();
        } catch (Exception e) {
        }
      }
    }

    // There should be a deoptimization here right after Main2 is linked by
    // calling Dummy.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 ((createMain2 || wait) && sHasJIT && !sIsOptimizing) {
      // This method should be deoptimized right after Main2 is created.
      assertIsInterpreted();
    }

    if (sMain2 != null) {
      sMain2.foo(sMain2.getClass() == Main1.class ? 1 : 2);
    }
  }

  static Main1[] sArray;

  static long calcValue(Main1 m) {
    return m.getValue1()
        + m.getValue2() * 2
        + m.getValue3() * 3
        + m.getValue4() * 4
        + m.getValue5() * 5
        + m.getValue6() * 6;
  }

  static long testNoOverrideLoop(int count) {
    long sum = 0;
    for (int i=0; i<count; i++) {
      sum += calcValue(sArray[0]);
      sum += calcValue(sArray[1]);
      sum += calcValue(sArray[2]);
    }
    return sum;
  }

  static void testNoOverride() {
    sArray = new Main1[3];
    sArray[0] = new Main1();
    sArray[1] = Dummy.createMain2();
    sArray[2] = Dummy.createMain3();
    long sum = 0;
    // Loop enough to get methods JITed.
    for (int i=0; i<100; i++) {
      testNoOverrideLoop(1);
    }
    ensureJitCompiled(Main.class, "testNoOverrideLoop");
    ensureJitCompiled(Main.class, "calcValue");

    long t1 = System.currentTimeMillis();
    sum = testNoOverrideLoop(100000);
    long t2 = System.currentTimeMillis();
    if (sum != 27300000L) {
      System.out.println("Unexpected result.");
    }
  }

  private static void assertSingleImplementation(Class<?> clazz, String method_name, boolean b) {
    if (hasSingleImplementation(clazz, method_name) != b) {
      System.out.println(clazz + "." + method_name +
          " doesn't have single implementation value of " + b);
    }
  }

  // Test scenarios under which CHA-based devirtualization happens,
  // and class loading that overrides a method can invalidate compiled code.
  // Also test pure non-overriding case, which is more for checking generated
  // code form.
  public static void main(String[] args) {
    System.loadLibrary(args[0]);

    // CHeck some boot-image methods.
    assertSingleImplementation(java.util.ArrayList.class, "size", true);
    // java.util.LinkedHashMap overrides get().
    assertSingleImplementation(java.util.HashMap.class, "get", false);

    // We don't set single-implementation modifier bit for final classes or methods
    // since we can devirtualize without CHA for those cases. However hasSingleImplementation()
    // should return true for those cases.
    assertSingleImplementation(java.lang.String.class, "charAt", true);
    assertSingleImplementation(java.lang.Thread.class, "join", true);

    if (isInterpreted()) {
      sIsOptimizing = false;
    }

    // sMain1 is an instance of Main1. Main2 hasn't bee loaded yet.
    sMain1 = new Main1();

    ensureJitCompiled(Main.class, "testOverride");
    testOverride(false, false, true);

    if (sHasJIT && !sIsOptimizing) {
      assertSingleImplementation(Main1.class, "foo", true);
    } else {
      // Main2 is verified ahead-of-time so it's linked in already.
    }
    assertSingleImplementation(Main1.class, "getValue1", true);

    // Create another thread that also calls sMain1.foo().
    // Try to test suspend and deopt another thread.
    new Thread() {
      public void run() {
        testOverride(false, true, false);
      }
    }.start();

    // This will create Main2 instance in the middle of testOverride().
    testOverride(true, false, false);
    assertSingleImplementation(Main1.class, "foo", false);
    assertSingleImplementation(Main1.class, "getValue1", true);

    testNoOverride();
  }

  private static native void ensureJitCompiled(Class<?> itf, String method_name);
  private static native void assertIsInterpreted();
  private static native void assertIsManaged();
  private static native boolean isInterpreted();
  private static native boolean hasSingleImplementation(Class<?> clazz, String method_name);
}

// Put createMain2() in another class to avoid class loading due to verifier.
class Dummy {
  static Main1 createMain2() {
    return new Main2();
  }
  static Main1 createMain3() {
    return new Main3();
  }
}