| /* |
| * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test |
| * @bug 8249719 |
| * @summary ResolvedMethodTable hash function should take method class into account |
| * @run main/othervm/manual -Xmx256m -XX:MaxMetaspaceSize=256m ResolvedMethodTableHash 200000 |
| */ |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodType; |
| import java.nio.ByteBuffer; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| // The test generates thousands MethodHandles to the methods of the same name |
| // and the same signature. This should not take too long, unless Method hash |
| // function takes only the name and the signature as an input. |
| public class ResolvedMethodTableHash extends ClassLoader { |
| |
| // Generate a MethodHandle for ClassName.m() |
| private MethodHandle generate(String className) throws ReflectiveOperationException { |
| byte[] buf = new byte[100]; |
| int size = writeClass(buf, className); |
| Class<?> cls = defineClass(null, buf, 0, size); |
| return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class)); |
| } |
| |
| private MethodHandle generateWithSameName() throws ReflectiveOperationException { |
| byte[] buf = new byte[100]; |
| int size = writeClass(buf, "MH$$"); |
| // use different classloader instances to load the classes with the same name |
| Class<?> cls = new ResolvedMethodTableHash().defineClass(null, buf, 0, size); |
| return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class)); |
| } |
| |
| // Produce a class file with the given name and a single method: |
| // public static native void m(); |
| private int writeClass(byte[] buf, String className) { |
| return ByteBuffer.wrap(buf) |
| .putInt(0xCAFEBABE) // magic |
| .putInt(50) // version: 50 |
| .putShort((short) 7) // constant_pool_count: 7 |
| .put((byte) 7).putShort((short) 2) |
| .put((byte) 1).putShort((short) className.length()).put(className.getBytes()) |
| .put((byte) 7).putShort((short) 4) |
| .put((byte) 1).putShort((short) 16).put("java/lang/Object".getBytes()) |
| .put((byte) 1).putShort((short) 1).put("m".getBytes()) |
| .put((byte) 1).putShort((short) 3).put("()V".getBytes()) |
| .putShort((short) 0x21) // access_flags: public super |
| .putShort((short) 1) // this_class: #1 |
| .putShort((short) 3) // super_class: #3 |
| .putShort((short) 0) // interfaces_count: 0 |
| .putShort((short) 0) // fields_count: 0 |
| .putShort((short) 1) // methods_count: 1 |
| .putShort((short) 0x109) // access_flags: public static native |
| .putShort((short) 5) // name_index: #5 |
| .putShort((short) 6) // descriptor_index: #6 |
| .putShort((short) 0) // attributes_count: 0 |
| .putShort((short) 0) // attributes_count: 0 |
| .position(); |
| } |
| |
| public static void main(String[] args) throws Exception { |
| ResolvedMethodTableHash generator = new ResolvedMethodTableHash(); |
| List<MethodHandle> handles = new ArrayList<>(); |
| |
| int count = args.length > 0 ? Integer.parseInt(args[0]) : 200000; |
| |
| for (int i = 0; i < count; i++) { |
| // prevents metaspace oom |
| if (i % 20 != 0) { |
| handles.add(generator.generate("MH$" + i)); |
| } else { |
| handles.add(generator.generateWithSameName()); |
| } |
| if (i % 1000 == 0) { |
| System.out.println("Generated " + i + " handles"); |
| } |
| } |
| |
| System.out.println("Test passed"); |
| } |
| } |