hotspot/test/compiler/intrinsics/string/TestStringEqualsBadLength.java
changeset 40059 c2304140ed64
parent 21523 49c80d56e5e3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/intrinsics/string/TestStringEqualsBadLength.java	Tue Jul 12 18:24:48 2016 +0300
@@ -0,0 +1,85 @@
+/*
+ * 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");
+    }
+}