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/*
* Copyright (c) 2013, 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 8027445
* @summary String.equals() may be called with a length whose upper bits are not cleared
*
* @run main/othervm -XX:-UseOnStackReplacement -XX:-BackgroundCompilation
* compiler.intrinsics.string.TestStringEqualsBadLength
*/
package compiler.intrinsics.string;
import java.util.Arrays;
public class TestStringEqualsBadLength {
int v1;
int v2;
boolean m(String s1) {
int l = v2 - v1; // 0 - (-1) = 1. On 64 bit: 0xffffffff00000001
char[] arr = new char[l];
arr[0] = 'a';
String s2 = new String(arr);
// The string length is not reloaded but the value computed is
// reused so pointer computation must not use
// 0xffffffff00000001
return s2.equals(s1);
}
// Same thing with String.compareTo()
int m2(String s1) {
int l = v2 - v1;
char[] arr = new char[l+1];
arr[0] = 'a';
arr[1] = 'b';
String s2 = new String(arr);
return s2.compareTo(s1);
}
// Same thing with equals() for arrays
boolean m3(char[] arr1) {
int l = v2 - v1; // 0 - (-1) = 1. On 64 bit: 0xffffffff00000001
char[] arr2 = new char[l];
arr2[0] = 'a';
return Arrays.equals(arr2, arr1);
}
static public void main(String[] args) {
TestStringEqualsBadLength tse = new TestStringEqualsBadLength();
tse.v1 = -1;
tse.v2 = 0;
char[] arr = new char[1];
arr[0] = 'a';
for (int i = 0; i < 20000; i++) {
tse.m("a");
tse.m2("ab");
tse.m3(arr);
}
System.out.println("TEST PASSED");
}
}
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