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 public class Main { 18 public static void main(String[] args) throws Exception { 19 System.loadLibrary(args[0]); 20 if (!hasJit()) { 21 return; 22 } 23 Foo.hotMethod(); 24 } 25 26 public native static boolean hasJitCompiledEntrypoint(Class<?> cls, String methodName); 27 private native static boolean hasJit(); 28 } 29 30 class Foo { 31 static void hotMethod() { 32 for (int i = 0; i < array.length; ++i) { 33 array[i] = array; 34 } 35 } 36 37 static { 38 array = new Object[10000]; 39 while (!Main.hasJitCompiledEntrypoint(Foo.class, "hotMethod")) { 40 Foo.hotMethod(); 41 try { 42 // Sleep to give a chance for the JIT to compile `hotMethod`. 43 Thread.sleep(100); 44 } catch (Exception e) { 45 // Ignore 46 } 47 } 48 } 49 50 static Object[] array; 51 } 52
