Mercurial > hg > graal-compiler
comparison graal/com.oracle.truffle.api/src/com/oracle/truffle/api/utilities/BooleanConditionProfile.java @ 16828:2834af86f398
Truffle: new condition profile primitives.
author | Christian Humer <christian.humer@gmail.com> |
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date | Wed, 13 Aug 2014 20:44:36 +0200 |
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16827:5e647663b77e | 16828:2834af86f398 |
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1 /* | |
2 * Copyright (c) 2013, 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 import com.oracle.truffle.api.*; | |
28 import com.oracle.truffle.api.CompilerDirectives.*; | |
29 | |
30 /** | |
31 * Utility class to speculate on conditions to be never true or to be never false. Condition | |
32 * profiles are intended to be used as part of if conditions. | |
33 * | |
34 * Example usage: | |
35 * | |
36 * <pre> | |
37 * private final ConditionProfile zero = new BooleanConditionProfile(); | |
38 * | |
39 * int value = ...; | |
40 * if (zero.profile(value == 0)) { | |
41 * return 0; | |
42 * } else { | |
43 * return value; | |
44 * } | |
45 * | |
46 * </pre> | |
47 * | |
48 * @see ConditionProfile | |
49 * @see IntegerConditionProfile | |
50 */ | |
51 public class BooleanConditionProfile extends ConditionProfile { | |
52 | |
53 @CompilationFinal private boolean wasTrue; | |
54 @CompilationFinal private boolean wasFalse; | |
55 | |
56 @Override | |
57 public boolean profile(boolean value) { | |
58 if (value) { | |
59 if (!wasTrue) { | |
60 CompilerDirectives.transferToInterpreterAndInvalidate(); | |
61 wasTrue = true; | |
62 } | |
63 } else { | |
64 if (!wasFalse) { | |
65 CompilerDirectives.transferToInterpreterAndInvalidate(); | |
66 wasFalse = true; | |
67 } | |
68 } | |
69 return value; | |
70 } | |
71 | |
72 public boolean wasTrue() { | |
73 return wasTrue; | |
74 } | |
75 | |
76 public boolean wasFalse() { | |
77 return wasFalse; | |
78 } | |
79 | |
80 @Override | |
81 public String toString() { | |
82 return String.format("%s(wasTrue=%s, wasFalse=%s)@%x", getClass().getSimpleName(), wasTrue, wasFalse, hashCode()); | |
83 } | |
84 } |