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comparison graal/com.oracle.truffle.api/src/com/oracle/truffle/api/utilities/ValueProfile.java @ 17039:1e542561783e

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Truffle: new value profiles prototype.
author Christian Humer <christian.humer@gmail.com>
date Wed, 03 Sep 2014 14:58:53 +0200
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children 53afdc71b311
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17038:3b3e768a2b92 17039:1e542561783e
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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package com.oracle.truffle.api.utilities;
26
27 /**
28 * Utility class to speculate on certain properties of values.
29 *
30 * Example usage:
31 *
32 * <pre>
33 * private final ValueProfile classProfile = ValueProfile.createClassProfile();
34 *
35 * return classProfile.profile(value);
36 * </pre>
37 *
38 * All instances of {@code ValueProfile} (and subclasses) must be held in {@code final} fields for
39 * compiler optimizations to take effect.
40 *
41 * @see #createIdentityProfile()
42 * @see #createClassProfile()
43 */
44 public abstract class ValueProfile {
45
46 public abstract <T> T profile(T value);
47
48 /**
49 * Returns a {@link ValueProfile} that speculates on the exact class of a value.
50 */
51 public static ValueProfile createClassProfile() {
52 return new ExactClassValueProfile();
53 }
54
55 /**
56 * Returns a {@link ValueProfile} that speculates on the object identity of a value.
57 */
58 public static ValueProfile createIdentityProfile() {
59 return new IdentityValueProfile();
60 }
61
62 }