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8237524: AArch64: String.compareTo() may return incorrect result

Reviewed-by: aph
  • Loading branch information
Pengfei Li
Pengfei Li committed Jan 21, 2020
1 parent c718a08 commit 6fd7ad87ce2565b8073b7caf7198c6a8eda1fa40
@@ -1,6 +1,6 @@
/*
* Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2014, 2019, Red Hat Inc. All rights reserved.
* Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2014, 2020, Red Hat Inc. 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
@@ -4977,8 +4977,6 @@ void MacroAssembler::string_compare(Register str1, Register str2,
sub(cnt2, zr, cnt2, LSL, str2_chr_shift);
} else if (isLU) {
ldrs(vtmp, Address(str1));
cmp(str1, str2);
br(Assembler::EQ, DONE);
ldr(tmp2, Address(str2));
cmp(cnt2, stub_threshold);
br(GE, STUB);
@@ -4993,8 +4991,6 @@ void MacroAssembler::string_compare(Register str1, Register str2,
fmovd(tmp1, vtmp);
} else { // UL case
ldr(tmp1, Address(str1));
cmp(str1, str2);
br(Assembler::EQ, DONE);
ldrs(vtmp, Address(str2));
cmp(cnt2, stub_threshold);
br(GE, STUB);
@@ -0,0 +1,62 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2020, Arm Limited. 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 8237524
* @summary String.compareTo() may return incorrect result in this case
*
* @run main/othervm compiler.intrinsics.Test8237524
*/

package compiler.intrinsics;

import java.lang.reflect.Constructor;

public class Test8237524 {

private static int stringCompareTo(String s1, String s2) {
return s1.compareTo(s2);
}

public static void main(String[] args) throws Exception {
Constructor<String> c = String.class.getDeclaredConstructor(byte[].class, byte.class);
c.setAccessible(true);

byte[] bytes = new byte[] {
'Y', 'm', '_', 'l', 'V', 'n', 'W', 'S', 'w', 'm', 'W', 'S'
};

String s1 = c.newInstance(bytes, (byte) 0); // a Latin string
String s2 = c.newInstance(bytes, (byte) 1); // a Chinese string

for (int i = 0; i < 50000; i++) {
if (stringCompareTo(s1, s2) >= 0) {
System.out.println("FAIL. s1 should be less than s2 according to Java API Spec");
System.exit(1);
}
}
}
}

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