1 /* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 8027445 27 * @summary String.equals() may be called with a length whose upper bits are not cleared 28 * 29 * @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation 30 * compiler.intrinsics.string.TestStringEqualsBadLength 31 */ 32 33 package compiler.intrinsics.string; 34 35 import java.util.Arrays; 36 37 public class TestStringEqualsBadLength { 38 39 int v1; 40 int v2; 41 42 boolean m(String s1) { 43 int l = v2 - v1; // 0 - (-1) = 1. On 64 bit: 0xffffffff00000001 44 char[] arr = new char[l]; 45 arr[0] = 'a'; 46 String s2 = new String(arr); 47 // The string length is not reloaded but the value computed is 48 // reused so pointer computation must not use 49 // 0xffffffff00000001 50 return s2.equals(s1); 51 } 52 53 // Same thing with String.compareTo() 54 int m2(String s1) { 55 int l = v2 - v1; 56 char[] arr = new char[l+1]; 57 arr[0] = 'a'; 58 arr[1] = 'b'; 59 String s2 = new String(arr); 60 return s2.compareTo(s1); 61 } 62 63 // Same thing with equals() for arrays 64 boolean m3(char[] arr1) { 65 int l = v2 - v1; // 0 - (-1) = 1. On 64 bit: 0xffffffff00000001 66 char[] arr2 = new char[l]; 67 arr2[0] = 'a'; 68 return Arrays.equals(arr2, arr1); 69 } 70 71 static public void main(String[] args) { 72 TestStringEqualsBadLength tse = new TestStringEqualsBadLength(); 73 tse.v1 = -1; 74 tse.v2 = 0; 75 char[] arr = new char[1]; 76 arr[0] = 'a'; 77 for (int i = 0; i < 20000; i++) { 78 tse.m("a"); 79 tse.m2("ab"); 80 tse.m3(arr); 81 } 82 83 System.out.println("TEST PASSED"); 84 } 85 }