| /* |
| * Copyright (c) 2019 SAP SE. 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 8221083 |
| * @requires vm.gc.Serial |
| * @requires vm.bits == 64 & vm.opt.final.UseCompressedOops == true |
| * @summary On ppc64, C1 erroneously emits a 32-bit compare instruction for oop compares. |
| * @modules java.base/jdk.internal.misc:+open |
| * @library /test/lib / |
| * @build jdk.test.whitebox.WhiteBox |
| * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox |
| * @run main/othervm -Xbatch -XX:-UseTLAB -Xmx4m -XX:+UseSerialGC -XX:HeapBaseMinAddress=0x700000000 |
| * -XX:CompileCommand=compileonly,compiler.codegen.TestOopCmp::nullTest |
| * -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. |
| * compiler.codegen.TestOopCmp |
| * @author [email protected] |
| */ |
| |
| package compiler.codegen; |
| |
| import jdk.test.whitebox.WhiteBox; |
| |
| public class TestOopCmp { |
| |
| private static Object nullObj = null; |
| |
| public static boolean nullTest(Object o) { |
| if (o == nullObj) { |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| public static void main(String args[]) { |
| |
| WhiteBox WB = WhiteBox.getWhiteBox(); |
| |
| // The test is started with -XX:HeapBaseMinAddress=0x700000000 and a |
| // small heap of only 4mb. This works pretty reliable and at least on |
| // Linux/Windows we will get a heap starting at 0x700000000. |
| // The test also runs with -XX:+UseSerialGC which means that we'll get |
| // eden starting at 0x700000000. |
| // Calling 'System.gc()' will clean up all the objects from eden, so if |
| // eden starts at 0x700000000 the first allocation right after the |
| // system GC will be allcoated right at address 0x700000000. |
| System.gc(); |
| String s = new String("I'm not null!!!"); |
| if (WB.getObjectAddress(s) == 0x700000000L) { |
| System.out.println("Got object at address 0x700000000"); |
| } |
| |
| // We call 'nullTest()' with the newly allocated String object. If it was |
| // allocated at 0x700000000, its 32 least-significant bits will be 0 and a |
| // 32-bit comparison with 'nullObj' (which is 'null') will yield true and |
| // result in a test failure. |
| // If the code generated for 'nullTest()' correctly performs a 64-bit |
| // comparison or if we didn't manage to allcoate 's' at 0x700000000 the |
| // test will always succeed. |
| for (int i = 0; i < 30_000; i++) { |
| if (nullTest(s)) { |
| throw new RuntimeException("Comparing non-null object with null returned 'true'"); |
| } |
| } |
| } |
| } |
