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comparison truffle/com.oracle.truffle.api/src/com/oracle/truffle/api/profiles/ByteValueProfile.java @ 22501:a63bda98cfdb

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Extract profiles into separate package. Add isProfilingEnabled in TruffleRuntime to disable profiling in the default runtime; Add low overhead profiles for primitives; Add LoopConditionProfile; Profile footprint/threadsafety improvements; Make toString implementations more consistent; Greatly enhanced javadoc documentation for profiles; Deprecate old profiles
author Christian Humer <christian.humer@oracle.com>
date Wed, 16 Dec 2015 16:38:13 +0100
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22500:fbe1eb7b4172 22501:a63bda98cfdb
1 /*
2 * Copyright (c) 2015, 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.profiles;
26
27 import com.oracle.truffle.api.CompilerDirectives;
28 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
29 import com.oracle.truffle.api.Truffle;
30
31 /**
32 * <p>
33 * Specialized value profile to capture certain properties of <code>byte</code> runtime values.
34 * Value profiles require a runtime check in their initialized state to verify their profiled
35 * assumption. Value profiles are limited to capture monomorphic profiles only. This means that if
36 * two or more values are profiled within a single profile then the profile has no effect. If the
37 * value assumption is invalidated in compiled code then it is invalidated.
38 * </p>
39 *
40 * <p>
41 * <b> Usage example: </b>
42 *
43 * <pre>
44 * class SampleNode extends Node {
45 *
46 * final ByteValueProfile profile = ByteValueProfile.createIdentityProfile();
47 *
48 * byte execute(byte input) {
49 * byte profiledValue = profile.profile(input);
50 * // compiler may know now more about profiledValue
51 * return profiledValue;
52 * }
53 * }
54 * </pre>
55 * <p>
56 *
57 *
58 * {@inheritDoc}
59 *
60 * @see #createIdentityProfile()
61 * @see ValueProfile
62 */
63 public abstract class ByteValueProfile extends Profile {
64
65 ByteValueProfile() {
66 }
67
68 public abstract byte profile(byte value);
69
70 /**
71 * Returns a value profile that profiles the exact value of a <code>byte</code>.
72 *
73 * @see ByteValueProfile
74 */
75 public static ByteValueProfile createIdentityProfile() {
76 if (Truffle.getRuntime().isProfilingEnabled()) {
77 return Enabled.create();
78 } else {
79 return Disabled.INSTANCE;
80 }
81 }
82
83 static final class Enabled extends ByteValueProfile {
84
85 private static final byte UNINITIALIZED = 0;
86 private static final byte SPECIALIZED = 1;
87 private static final byte GENERIC = 2;
88
89 @CompilationFinal private byte cachedValue;
90 @CompilationFinal private byte state = 0;
91
92 @Override
93 public byte profile(byte value) {
94 byte localState = this.state;
95 if (localState != GENERIC) {
96 if (localState == SPECIALIZED) {
97 byte v = cachedValue;
98 if (v == value) {
99 return v;
100 }
101 }
102 CompilerDirectives.transferToInterpreterAndInvalidate();
103 if (localState == UNINITIALIZED) {
104 this.cachedValue = value;
105 this.state = SPECIALIZED;
106 } else {
107 this.state = GENERIC;
108 }
109 }
110 return value;
111 }
112
113 boolean isGeneric() {
114 return state == GENERIC;
115 }
116
117 boolean isUninitialized() {
118 return state == UNINITIALIZED;
119 }
120
121 byte getCachedValue() {
122 return cachedValue;
123 }
124
125 @Override
126 public String toString() {
127 return toString(ByteValueProfile.class, state == UNINITIALIZED, state == GENERIC, //
128 String.format("value == (byte)%s", cachedValue));
129 }
130
131 /* Needed for lazy class loading. */
132 static ByteValueProfile create() {
133 return new Enabled();
134 }
135 }
136
137 static final class Disabled extends ByteValueProfile {
138
139 static final ByteValueProfile INSTANCE = new Disabled();
140
141 @Override
142 protected Object clone() {
143 return INSTANCE;
144 }
145
146 @Override
147 public byte profile(byte value) {
148 return value;
149 }
150
151 @Override
152 public String toString() {
153 return toStringDisabled(ByteValueProfile.class);
154 }
155
156 }
157
158 }