1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/test/compiler/unsafe/TestRawAliasing.java Tue Jul 25 10:10:41 2017 -0400
1.3 @@ -0,0 +1,70 @@
1.4 +/*
1.5 + * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + */
1.26 +
1.27 +/*
1.28 + * @test
1.29 + * @bug 8178047
1.30 + * @run main/othervm -XX:CompileCommand=exclude,*.main -XX:-TieredCompilation -XX:-BackgroundCompilation compiler.unsafe.TestRawAliasing
1.31 + */
1.32 +
1.33 +package compiler.unsafe;
1.34 +
1.35 +import java.lang.reflect.Field;
1.36 +
1.37 +public class TestRawAliasing {
1.38 + static private final sun.misc.Unsafe UNSAFE;
1.39 + static {
1.40 + try {
1.41 + Field f = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1.42 + f.setAccessible(true);
1.43 + UNSAFE = (sun.misc.Unsafe) f.get(null);
1.44 + } catch (Exception e) {
1.45 + throw new RuntimeException("Unable to get Unsafe instance.", e);
1.46 + }
1.47 + }
1.48 +
1.49 + static private final int OFFSET_X = 50;
1.50 + static private final int OFFSET_Y = 100;
1.51 +
1.52 + private static int test(long base_plus_offset_x, long base_plus_offset_y, int magic_value) {
1.53 + // write 0 to a location
1.54 + UNSAFE.putByte(base_plus_offset_x - OFFSET_X, (byte)0);
1.55 + // write unfoldable value to really the same location with another base
1.56 + UNSAFE.putByte(base_plus_offset_y - OFFSET_Y, (byte)magic_value);
1.57 + // read the value back, should be equal to "unfoldable_value"
1.58 + return UNSAFE.getByte(base_plus_offset_x - OFFSET_X);
1.59 + }
1.60 +
1.61 + private static final int OFF_HEAP_AREA_SIZE = 128;
1.62 + private static final byte MAGIC = 123;
1.63 +
1.64 + // main is excluded from compilation since we don't want the test method to inline and make base values fold
1.65 + public static void main(String... args) {
1.66 + long base = UNSAFE.allocateMemory(OFF_HEAP_AREA_SIZE);
1.67 + for (int i = 0; i < 100_000; i++) {
1.68 + if (test(base + OFFSET_X, base + OFFSET_Y, MAGIC) != MAGIC) {
1.69 + throw new RuntimeException("Unexpected magic value");
1.70 + }
1.71 + }
1.72 + }
1.73 +}
