158 lines
4.5 KiB
Java
158 lines
4.5 KiB
Java
/*
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* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @bug 8237767
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* @summary Verify behaviour of field layout algorithm
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* @library /test/lib
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* @modules java.base/jdk.internal.misc
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* java.management
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* @run main/othervm FieldDensityTest
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*/
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/*
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* @test
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* @requires vm.bits == "64"
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* @library /test/lib
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* @modules java.base/jdk.internal.misc
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* java.management
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* @run main/othervm -XX:+UseCompressedOops -XX:+UseCompressedClassPointers FieldDensityTest
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* @run main/othervm -XX:+UseCompressedOops -XX:-UseCompressedClassPointers FieldDensityTest
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*/
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import java.lang.reflect.Field;
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import java.util.Arrays;
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import java.util.Comparator;
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import jdk.internal.misc.Unsafe;
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import jdk.test.lib.Asserts;
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public class FieldDensityTest {
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static int OOP_SIZE_IN_BYTES = 0;
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static {
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if (System.getProperty("sun.arch.data.model").equals("64")) {
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if (System.getProperty("java.vm.compressedOopsMode") == null) {
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OOP_SIZE_IN_BYTES = 8;
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} else {
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OOP_SIZE_IN_BYTES = 4;
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}
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} else {
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OOP_SIZE_IN_BYTES = 4;
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}
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}
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static class FieldInfo {
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public Field field;
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public long offset;
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FieldInfo(Field field, long offset) {
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this.field = field;
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this.offset = offset;
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}
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static void checkFieldsContiguity(FieldInfo[] fieldInfo) {
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Arrays.sort(fieldInfo, new SortByOffset());
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for (int i = 0 ; i < fieldInfo.length - 2; i++) {
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int size = sizeInBytesFromType(fieldInfo[i].field.getType());
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Asserts.assertEquals((int)(fieldInfo[i].offset + size), (int)fieldInfo[i+1].offset,
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"Empty slot between fields, should not happen");
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}
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}
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}
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static int sizeInBytesFromType(Class type) {
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if (!type.isPrimitive()) {
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return OOP_SIZE_IN_BYTES;
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}
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switch(type.getTypeName()) {
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case "boolean":
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case "byte": return 1;
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case "char":
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case "short": return 2;
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case "int":
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case "float": return 4;
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case "long":
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case "double": return 8;
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default:
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throw new RuntimeException("Unrecognized signature");
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}
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}
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static class SortByOffset implements Comparator<FieldInfo> {
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public int compare(FieldInfo a, FieldInfo b)
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{
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return (int)(a.offset - b.offset);
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}
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}
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static class E {
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public byte b0;
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}
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static class F extends E {
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public byte b1;
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}
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static class G extends F {
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public byte b2;
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}
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static class H extends G {
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public byte b3;
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}
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public static class A {
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public int i;
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public byte b;
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public long l;
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public Object o;
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}
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public static class B extends A {
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public byte b0, b1, b2;
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}
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static void testFieldsContiguity(Class c) {
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Unsafe unsafe = Unsafe.getUnsafe();
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Field[] fields = c.getFields();
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FieldInfo[] fieldsInfo = new FieldInfo[fields.length];
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int i = 0;
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for (Field f : fields) {
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long offset = unsafe.objectFieldOffset(f);
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fieldsInfo[i] = new FieldInfo(f, offset);
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i++;
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}
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FieldInfo.checkFieldsContiguity(fieldsInfo);
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}
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public static void main(String[] args) {
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H h = new H();
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testFieldsContiguity(h.getClass());
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B b = new B();
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testFieldsContiguity(b.getClass());
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}
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}
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