hotspot/test/compiler/stable/TestStableDouble.java
changeset 23192 f6a1c8866065
child 25641 d99065e4572b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/stable/TestStableDouble.java	Tue Mar 04 02:20:41 2014 -0800
@@ -0,0 +1,632 @@
+/*
+ * Copyright (c) 2014, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 TestStableDouble
+ * @summary tests on stable fields and arrays
+ * @library /testlibrary
+ * @compile -XDignore.symbol.file TestStableDouble.java
+ * @run main ClassFileInstaller
+ *           java/lang/invoke/TestStableDouble
+ *           java/lang/invoke/TestStableDouble$DoubleStable
+ *           java/lang/invoke/TestStableDouble$StaticDoubleStable
+ *           java/lang/invoke/TestStableDouble$VolatileDoubleStable
+ *           java/lang/invoke/TestStableDouble$DoubleArrayDim1
+ *           java/lang/invoke/TestStableDouble$DoubleArrayDim2
+ *           java/lang/invoke/TestStableDouble$DoubleArrayDim3
+ *           java/lang/invoke/TestStableDouble$DoubleArrayDim4
+ *           java/lang/invoke/TestStableDouble$ObjectArrayLowerDim0
+ *           java/lang/invoke/TestStableDouble$ObjectArrayLowerDim1
+ *           java/lang/invoke/TestStableDouble$NestedStableField
+ *           java/lang/invoke/TestStableDouble$NestedStableField$A
+ *           java/lang/invoke/TestStableDouble$NestedStableField1
+ *           java/lang/invoke/TestStableDouble$NestedStableField1$A
+ *           java/lang/invoke/TestStableDouble$NestedStableField2
+ *           java/lang/invoke/TestStableDouble$NestedStableField2$A
+ *           java/lang/invoke/TestStableDouble$NestedStableField3
+ *           java/lang/invoke/TestStableDouble$NestedStableField3$A
+ *           java/lang/invoke/TestStableDouble$DefaultValue
+ *           java/lang/invoke/TestStableDouble$ObjectArrayLowerDim2
+ *
+ * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:+FoldStableValues -XX:+UseCompressedOop
+ *                   -server -XX:-TieredCompilation -Xcomp
+ *                   -XX:CompileOnly=::get,::get1,::get2,::get3,::get4
+ *                   java.lang.invoke.TestStableDouble
+ *
+ * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:+FoldStableValues -XX:-UseCompressedOop
+ *                   -server -XX:-TieredCompilation -Xcomp
+ *                   -XX:CompileOnly=::get,::get1,::get2,::get3,::get4
+ *                   java.lang.invoke.TestStableDouble
+ *
+ * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:-FoldStableValues -XX:+UseCompressedOop
+ *                   -server -XX:-TieredCompilation -Xcomp
+ *                   -XX:CompileOnly=::get,::get1,::get2,::get3,::get4
+ *                   java.lang.invoke.TestStableDouble
+ *
+ * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:-FoldStableValues -XX:-UseCompressedOop
+ *                   -server -XX:-TieredCompilation -Xcomp
+ *                   -XX:CompileOnly=::get,::get1,::get2,::get3,::get4
+ *                   java.lang.invoke.TestStableDouble
+ */
+package java.lang.invoke;
+
+import com.sun.management.HotSpotDiagnosticMXBean;
+import com.sun.management.VMOption;
+import sun.management.ManagementFactoryHelper;
+import java.lang.reflect.InvocationTargetException;
+
+public class TestStableDouble {
+    public static void main(String[] args) throws Exception {
+        System.out.println("@Stable enabled: "+isStableEnabled);
+        System.out.println();
+
+        run(DefaultValue.class);
+        run(DoubleStable.class);
+        run(StaticDoubleStable.class);
+        run(VolatileDoubleStable.class);
+
+        // @Stable arrays: Dim 1-4
+        run(DoubleArrayDim1.class);
+        run(DoubleArrayDim2.class);
+        run(DoubleArrayDim3.class);
+        run(DoubleArrayDim4.class);
+
+        // @Stable Object field: dynamic arrays
+        run(ObjectArrayLowerDim0.class);
+        run(ObjectArrayLowerDim1.class);
+        run(ObjectArrayLowerDim2.class);
+
+        // Nested @Stable fields
+        run(NestedStableField.class);
+        run(NestedStableField1.class);
+        run(NestedStableField2.class);
+        run(NestedStableField3.class);
+
+        if (failed) {
+            throw new Error("TEST FAILED");
+        }
+    }
+
+    /* ==================================================== */
+
+    static class DefaultValue {
+        public @Stable double v;
+
+        public static final DefaultValue c = new DefaultValue();
+        public static double get() { return c.v; }
+        public static void test() throws Exception {
+                       double val1 = get();
+            c.v = 1.0; double val2 = get();
+            assertEquals(val1, 0);
+            assertEquals(val2, 1.0);
+        }
+    }
+
+    /* ==================================================== */
+
+    static class DoubleStable {
+        public @Stable double v;
+
+        public static final DoubleStable c = new DoubleStable();
+        public static double get() { return c.v; }
+        public static void test() throws Exception {
+            c.v = 1.0; double val1 = get();
+            c.v = Double.MAX_VALUE; double val2 = get();
+            assertEquals(val1, 1.0);
+            assertEquals(val2, (isStableEnabled ? 1.0 : Double.MAX_VALUE));
+        }
+    }
+
+    /* ==================================================== */
+
+    static class StaticDoubleStable {
+        public static @Stable double v;
+
+        public static final StaticDoubleStable c = new StaticDoubleStable();
+        public static double get() { return c.v; }
+        public static void test() throws Exception {
+            c.v = 1.0; double val1 = get();
+            c.v = Double.MAX_VALUE; double val2 = get();
+            assertEquals(val1, 1.0);
+            assertEquals(val2, (isStableEnabled ? 1.0 : Double.MAX_VALUE));
+        }
+    }
+
+    /* ==================================================== */
+
+    static class VolatileDoubleStable {
+        public @Stable double v;
+
+        public static final VolatileDoubleStable c = new VolatileDoubleStable();
+        public static double get() { return c.v; }
+        public static void test() throws Exception {
+            c.v = 1.0; double val1 = get();
+            c.v = Double.MAX_VALUE; double val2 = get();
+            assertEquals(val1, 1.0);
+            assertEquals(val2, (isStableEnabled ? 1.0 : Double.MAX_VALUE));
+        }
+    }
+
+    /* ==================================================== */
+    // @Stable array == field && all components are stable
+
+    static class DoubleArrayDim1 {
+        public @Stable double[] v;
+
+        public static final DoubleArrayDim1 c = new DoubleArrayDim1();
+        public static double get() { return c.v[0]; }
+        public static double get1() { return c.v[10]; }
+        public static double[] get2() { return c.v; }
+        public static void test() throws Exception {
+            {
+                c.v = new double[1]; c.v[0] = 1.0; double val1 = get();
+                                     c.v[0] = 2.0; double val2 = get();
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+
+                c.v = new double[1]; c.v[0] = 3.0; double val3 = get();
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+            }
+
+            {
+                c.v = new double[20]; c.v[10] = 1.0; double val1 = get1();
+                                      c.v[10] = 2.0; double val2 = get1();
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+
+                c.v = new double[20]; c.v[10] = 3.0; double val3 = get1();
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+            }
+
+            {
+                c.v = new double[1]; double[] val1 = get2();
+                c.v = new double[1]; double[] val2 = get2();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class DoubleArrayDim2 {
+        public @Stable double[][] v;
+
+        public static final DoubleArrayDim2 c = new DoubleArrayDim2();
+        public static double get() { return c.v[0][0]; }
+        public static double[] get1() { return c.v[0]; }
+        public static double[][] get2() { return c.v; }
+        public static void test() throws Exception {
+            {
+                c.v = new double[1][1]; c.v[0][0] = 1.0; double val1 = get();
+                                        c.v[0][0] = 2.0; double val2 = get();
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+
+                c.v = new double[1][1]; c.v[0][0] = 3.0; double val3 = get();
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+
+                c.v[0] = new double[1]; c.v[0][0] = 4.0; double val4 = get();
+                assertEquals(val4, (isStableEnabled ? 1.0 : 4.0));
+            }
+
+            {
+                c.v = new double[1][1]; double[] val1 = get1();
+                c.v[0] = new double[1]; double[] val2 = get1();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1]; double[][] val1 = get2();
+                c.v = new double[1][1]; double[][] val2 = get2();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class DoubleArrayDim3 {
+        public @Stable double[][][] v;
+
+        public static final DoubleArrayDim3 c = new DoubleArrayDim3();
+        public static double get() { return c.v[0][0][0]; }
+        public static double[] get1() { return c.v[0][0]; }
+        public static double[][] get2() { return c.v[0]; }
+        public static double[][][] get3() { return c.v; }
+        public static void test() throws Exception {
+            {
+                c.v = new double[1][1][1]; c.v[0][0][0] = 1.0; double val1 = get();
+                                           c.v[0][0][0] = 2.0; double val2 = get();
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+
+                c.v = new double[1][1][1]; c.v[0][0][0] = 3.0; double val3 = get();
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+
+                c.v[0] = new double[1][1]; c.v[0][0][0] = 4.0; double val4 = get();
+                assertEquals(val4, (isStableEnabled ? 1.0 : 4.0));
+
+                c.v[0][0] = new double[1]; c.v[0][0][0] = 5.0; double val5 = get();
+                assertEquals(val5, (isStableEnabled ? 1.0 : 5.0));
+            }
+
+            {
+                c.v = new double[1][1][1]; double[] val1 = get1();
+                c.v[0][0] = new double[1]; double[] val2 = get1();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1]; double[][] val1 = get2();
+                c.v[0] = new double[1][1]; double[][] val2 = get2();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1]; double[][][] val1 = get3();
+                c.v = new double[1][1][1]; double[][][] val2 = get3();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class DoubleArrayDim4 {
+        public @Stable double[][][][] v;
+
+        public static final DoubleArrayDim4 c = new DoubleArrayDim4();
+        public static double get() { return c.v[0][0][0][0]; }
+        public static double[] get1() { return c.v[0][0][0]; }
+        public static double[][] get2() { return c.v[0][0]; }
+        public static double[][][] get3() { return c.v[0]; }
+        public static double[][][][] get4() { return c.v; }
+        public static void test() throws Exception {
+            {
+                c.v = new double[1][1][1][1]; c.v[0][0][0][0] = 1.0; double val1 = get();
+                                              c.v[0][0][0][0] = 2.0; double val2 = get();
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+
+                c.v = new double[1][1][1][1]; c.v[0][0][0][0] = 3.0; double val3 = get();
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+
+                c.v[0] = new double[1][1][1]; c.v[0][0][0][0] = 4.0; double val4 = get();
+                assertEquals(val4, (isStableEnabled ? 1.0 : 4.0));
+
+                c.v[0][0] = new double[1][1]; c.v[0][0][0][0] = 5.0; double val5 = get();
+                assertEquals(val5, (isStableEnabled ? 1.0 : 5.0));
+
+                c.v[0][0][0] = new double[1]; c.v[0][0][0][0] = 6.0; double val6 = get();
+                assertEquals(val6, (isStableEnabled ? 1.0 : 6.0));
+            }
+
+            {
+                c.v = new double[1][1][1][1]; double[] val1 = get1();
+                c.v[0][0][0] = new double[1]; double[] val2 = get1();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1][1]; double[][] val1 = get2();
+                c.v[0][0] = new double[1][1]; double[][] val2 = get2();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1][1]; double[][][] val1 = get3();
+                c.v[0] = new double[1][1][1]; double[][][] val2 = get3();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1][1]; double[][][][] val1 = get4();
+                c.v = new double[1][1][1][1]; double[][][][] val2 = get4();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+        }
+    }
+
+    /* ==================================================== */
+    // Dynamic Dim is higher than static
+
+    static class ObjectArrayLowerDim0 {
+        public @Stable Object v;
+
+        public static final ObjectArrayLowerDim0 c = new ObjectArrayLowerDim0();
+        public static double get() { return ((double[])c.v)[0]; }
+        public static double[] get1() { return (double[])c.v; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new double[1]; ((double[])c.v)[0] = 1.0; double val1 = get();
+                                     ((double[])c.v)[0] = 2.0; double val2 = get();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val2, 2.0);
+            }
+
+            {
+                c.v = new double[1]; double[] val1 = get1();
+                c.v = new double[1]; double[] val2 = get1();
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class ObjectArrayLowerDim1 {
+        public @Stable Object[] v;
+
+        public static final ObjectArrayLowerDim1 c = new ObjectArrayLowerDim1();
+        public static double get() { return ((double[][])c.v)[0][0]; }
+        public static double[] get1() { return (double[])(c.v[0]); }
+        public static Object[] get2() { return c.v; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new double[1][1]; ((double[][])c.v)[0][0] = 1.0; double val1 = get();
+                                        ((double[][])c.v)[0][0] = 2.0; double val2 = get();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val2, 2.0);
+            }
+
+            {
+                c.v = new double[1][1]; c.v[0] = new double[0]; double[] val1 = get1();
+                                        c.v[0] = new double[0]; double[] val2 = get1();
+
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[0][0]; Object[] val1 = get2();
+                c.v = new double[0][0]; Object[] val2 = get2();
+
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class ObjectArrayLowerDim2 {
+        public @Stable Object[][] v;
+
+        public static final ObjectArrayLowerDim2 c = new ObjectArrayLowerDim2();
+        public static double get() { return ((double[][][])c.v)[0][0][0]; }
+        public static double[] get1() { return (double[])(c.v[0][0]); }
+        public static double[][] get2() { return (double[][])(c.v[0]); }
+        public static Object[][] get3() { return c.v; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new double[1][1][1]; ((double[][][])c.v)[0][0][0] = 1.0; double val1 = get();
+                                           ((double[][][])c.v)[0][0][0] = 2.0; double val2 = get();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val2, 2.0);
+            }
+
+            {
+                c.v = new double[1][1][1]; c.v[0][0] = new double[0]; double[] val1 = get1();
+                                           c.v[0][0] = new double[0]; double[] val2 = get1();
+
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[1][1][1]; c.v[0] = new double[0][0]; double[][] val1 = get2();
+                                           c.v[0] = new double[0][0]; double[][] val2 = get2();
+
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+
+            {
+                c.v = new double[0][0][0]; Object[][] val1 = get3();
+                c.v = new double[0][0][0]; Object[][] val2 = get3();
+
+                assertTrue((isStableEnabled ? (val1 == val2) : (val1 != val2)));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class NestedStableField {
+        static class A {
+            public @Stable double a;
+
+        }
+        public @Stable A v;
+
+        public static final NestedStableField c = new NestedStableField();
+        public static A get() { return c.v; }
+        public static double get1() { return get().a; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new A(); c.v.a = 1.0; A val1 = get();
+                               c.v.a = 2.0; A val2 = get();
+
+                assertEquals(val1.a, 2.0);
+                assertEquals(val2.a, 2.0);
+            }
+
+            {
+                c.v = new A(); c.v.a = 1.0; double val1 = get1();
+                               c.v.a = 2.0; double val2 = get1();
+                c.v = new A(); c.v.a = 3.0; double val3 = get1();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class NestedStableField1 {
+        static class A {
+            public @Stable double a;
+            public @Stable A next;
+        }
+        public @Stable A v;
+
+        public static final NestedStableField1 c = new NestedStableField1();
+        public static A get() { return c.v.next.next.next.next.next.next.next; }
+        public static double get1() { return get().a; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new A(); c.v.next = new A();   c.v.next.next  = c.v;
+                               c.v.a = 1.0; c.v.next.a = 1.0; A val1 = get();
+                               c.v.a = 2.0; c.v.next.a = 2.0; A val2 = get();
+
+                assertEquals(val1.a, 2.0);
+                assertEquals(val2.a, 2.0);
+            }
+
+            {
+                c.v = new A(); c.v.next = c.v;
+                               c.v.a = 1.0; double val1 = get1();
+                               c.v.a = 2.0; double val2 = get1();
+                c.v = new A(); c.v.next = c.v;
+                               c.v.a = 3.0; double val3 = get1();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val2, (isStableEnabled ? 1.0 : 2.0));
+                assertEquals(val3, (isStableEnabled ? 1.0 : 3.0));
+            }
+        }
+    }
+   /* ==================================================== */
+
+    static class NestedStableField2 {
+        static class A {
+            public @Stable double a;
+            public @Stable A left;
+            public         A right;
+        }
+
+        public @Stable A v;
+
+        public static final NestedStableField2 c = new NestedStableField2();
+        public static double get() { return c.v.left.left.left.a; }
+        public static double get1() { return c.v.left.left.right.left.a; }
+
+        public static void test() throws Exception {
+            {
+                c.v = new A(); c.v.left = c.v.right = c.v;
+                               c.v.a = 1.0; double val1 = get(); double val2 = get1();
+                               c.v.a = 2.0; double val3 = get(); double val4 = get1();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val3, (isStableEnabled ? 1.0 : 2.0));
+
+                assertEquals(val2, 1.0);
+                assertEquals(val4, 2.0);
+            }
+        }
+    }
+
+    /* ==================================================== */
+
+    static class NestedStableField3 {
+        static class A {
+            public @Stable double a;
+            public @Stable A[] left;
+            public         A[] right;
+        }
+
+        public @Stable A[] v;
+
+        public static final NestedStableField3 c = new NestedStableField3();
+        public static double get() { return c.v[0].left[1].left[0].left[1].a; }
+        public static double get1() { return c.v[1].left[0].left[1].right[0].left[1].a; }
+
+        public static void test() throws Exception {
+            {
+                A elem = new A();
+                c.v = new A[] { elem, elem }; c.v[0].left = c.v[0].right = c.v;
+                               elem.a = 1.0; double val1 = get(); double val2 = get1();
+                               elem.a = 2.0; double val3 = get(); double val4 = get1();
+
+                assertEquals(val1, 1.0);
+                assertEquals(val3, (isStableEnabled ? 1.0 : 2.0));
+
+                assertEquals(val2, 1.0);
+                assertEquals(val4, 2.0);
+            }
+        }
+    }
+
+    /* ==================================================== */
+    // Auxiliary methods
+    static void assertEquals(double i, double j) { if (i != j)  throw new AssertionError(i + " != " + j); }
+    static void assertTrue(boolean b) { if (!b)  throw new AssertionError(); }
+
+    static boolean failed = false;
+
+    public static void run(Class<?> test) {
+        Throwable ex = null;
+        System.out.print(test.getName()+": ");
+        try {
+            test.getMethod("test").invoke(null);
+        } catch (InvocationTargetException e) {
+            ex = e.getCause();
+        } catch (Throwable e) {
+            ex = e;
+        } finally {
+            if (ex == null) {
+                System.out.println("PASSED");
+            } else {
+                failed = true;
+                System.out.println("FAILED");
+                ex.printStackTrace(System.out);
+            }
+        }
+    }
+
+    static final boolean isStableEnabled;
+    static {
+        HotSpotDiagnosticMXBean diagnostic
+                = ManagementFactoryHelper.getDiagnosticMXBean();
+        VMOption tmp;
+        try {
+            tmp = diagnostic.getVMOption("FoldStableValues");
+        } catch (IllegalArgumentException e) {
+            tmp = null;
+        }
+        isStableEnabled = (tmp == null ? false : Boolean.parseBoolean(tmp.getValue()));
+    }
+}