StableConfiguration.java revision 10420:c558850fac57 
1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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24 */
25
26package compiler.stable;
27
28import sun.hotspot.WhiteBox;
29
30import java.lang.reflect.Method;
31
32public class StableConfiguration {
33    static final WhiteBox WB = WhiteBox.getWhiteBox();
34    public static final boolean isStableEnabled;
35    public static final boolean isServerWithStable;
36
37    static {
38        Boolean value = WB.getBooleanVMFlag("FoldStableValues");
39        isStableEnabled = (value == null ? false : value);
40        isServerWithStable = isStableEnabled && get();
41        System.out.println("@Stable:         " + (isStableEnabled ? "enabled" : "disabled"));
42        System.out.println("Server Compiler: " + get());
43    }
44
45    // The method 'get' below returns true if the method is server compiled
46    // and is used by the Stable tests to determine whether methods in
47    // general are being server compiled or not as the -XX:+FoldStableValues
48    // option is only applicable to -server.
49    //
50    // On aarch64 we DeOptimize when patching. This means that when the
51    // method is compiled as a result of -Xcomp it DeOptimizes immediately.
52    // The result is that getMethodCompilationLevel returns 0. This means
53    // the method returns true based on java.vm.name.
54    //
55    // However when the tests are run with -XX:+TieredCompilation and
56    // -XX:TieredStopAtLevel=1 this fails because methods will always
57    // be client compiled.
58    //
59    // Solution is to add a simple method 'get1' which should never be
60    // DeOpted and use that to determine the compilation level instead.
61    static void get1() {
62    }
63
64    // ::get() is among immediately compiled methods.
65    static boolean get() {
66        try {
67            get1();
68            Method m = StableConfiguration.class.getDeclaredMethod("get1");
69            int level = WB.getMethodCompilationLevel(m);
70            if (level > 0) {
71              return (level == 4);
72            } else {
73              String javaVM = System.getProperty("java.vm.name", "");
74              if (javaVM.contains("Server")) return true;
75              if (javaVM.contains("Client")) return false;
76              throw new Error("Unknown VM type: "+javaVM);
77            }
78        } catch (NoSuchMethodException e) {
79            throw new Error(e);
80        }
81    }
82}
83