view test/compiler/6478991/NullCheckTest.java @ 10246:194f52aa2f23

7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich. Reviewed-by: tschatzl, jmasa
author johnc
date Thu, 09 May 2013 11:16:39 -0700
parents 15559220ce79
children
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/*
 * Copyright (c) 2011, 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 6478991
 * @summary C1 NullCheckEliminator yields incorrect exceptions
 *
 * @run main/othervm -XX:CompileOnly=NullCheckTest.test,NullCheckTest.inlined  -Xcomp NullCheckTest
 */

public class NullCheckTest {
        static class A {
                int f;

                public final void inlined(A a) {
                        // This cast is intended to fail.
                        B b = ((B) a);
                }
        }

        static class B extends A {
        }


        private static void test(A a1, A a2) {
                // Inlined call must do a null check on a1.
                // However, the exlipcit NullCheck instruction is eliminated and
                // the null check is folded into the field load below, so the
                // exception in the inlined method is thrown before the null check
                // and the NullPointerException is not thrown.
                a1.inlined(a2);

                int x = a1.f;
        }

        public static void main(String[] args) {
                // load classes
                new B();
                try {
                        test(null, new A());

                        throw new InternalError("FAILURE: no exception");
                } catch (NullPointerException ex) {
                        System.out.println("CORRECT: NullPointerException");
                } catch (ClassCastException ex) {
                        System.out.println("FAILURE: ClassCastException");
                        throw ex;
                }
        }
}