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Truffle/Instrumentation: package-info for com.oracle.truffle.api.instrument
author Michael Van De Vanter <michael.van.de.vanter@oracle.com>
date Mon, 21 Sep 2015 21:21:29 -0700
parents 11e0412c5b0e
children c1c9c6d79f40
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22234:959f658b918d 22235:e110ab9f91fe
22 * or visit www.oracle.com if you need additional information or have any 22 * or visit www.oracle.com if you need additional information or have any
23 * questions. 23 * questions.
24 */ 24 */
25 25
26 /** 26 /**
27 * Advanced node manipulation instruments. 27 * <h4>The Truffle Instrumentation Framework</h4>
28 * <p>
29 * This framework permits client
30 * {@linkplain com.oracle.truffle.api.iknstrument.Instrumenter.Tool tools},
31 * either builtin or third-party, to observe with <em>very low overhead</em> the execution of a
32 * {@linkplain com.oracle.truffle.api.TruffleLanguage Truffle Language} program at the level of
33 * <em>AST execution events</em>:
34 * <ul>
35 * <li>a Truffle
36 * {@linkplain com.oracle.truffle.api.nodes.Node Node} is about to be executed, or</li>
37 * <li>a Truffle
38 * {@linkplain com.oracle.truffle.api.nodes.Node Node} execution has just completed.</li>
39 * </ul>
40 * The framework supports many kinds of tools, for example simple collectors of data such as
41 * {@linkplain com.oracle.truffle.tools.CoverageTracker code coverage}.
42 * It also supports Truffle's built-in
43 * {@linkplain com.oracle.truffle.api.debug.Debugger debugging services}, as well as utilities
44 * that maintain {@linkplain com.oracle.truffle.tools.LineToProbesMap maps of source code locations}
45 * for other tools such as {@linkplain com.oracle.truffle.api.debug.Debugger debugging}.
46 *
47 * <h4>Instrumentation Services</h4>
48 * <p>
49 * API access to instrumentation services is provided by the
50 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter Instrumenter} that is part of
51 * the Truffle execution environment. These services fall into several categories:
52 *
53 * <ul>
54 *
55 * <li><strong>AST Markup: probing</strong>
56 * <ul>
57 * <li>Execution events can only be observed at AST locations that have been
58 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#probe(com.oracle.truffle.api.nodes.Node) probed},
59 * which results in the creation of a
60 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} that is permanently associated with a
61 * particular segment of source code, e.g. a "statement", that corresponds to an AST location.</li>
62 * <li>Probing is only supported at
63 * {@linkplain com.oracle.truffle.api.nodes.Node Nodes} that are implemented to be
64 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#isInstrumentable(com.oracle.truffle.api.nodes.Node)
65 * instrumentable}.</li>
66 * <li>The relationship between a
67 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} and
68 * a source code location persists across Truffle <em>cloning</em> of ASTs, which is to say, a single
69 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} corresponds to (and keeps track of)
70 * the equivalent location in every clone of the original AST.</li>
71 * <li>Probing is specified by
72 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#registerASTProber(ASTProber) registering}
73 * an instance of
74 * {@linkplain com.oracle.truffle.api.instrument.ASTProber ASTProber}.
75 * A default prober provided by each {@linkplain com.oracle.truffle.api.TruffleLanguage TruffelLanguage}
76 * will be registered automatically.</li>
77 * <li>All AST probing must be complete before any AST execution has started.</li>
78 * </ul></li>
79 *
80 * <li><strong>AST Markup: tagging</strong>
81 * <ul>
82 * <li>Additional information can be added at any time to a
83 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} by
84 * {@linkplain com.oracle.truffle.api.instrument.Probe#tagAs(SyntaxTag, Object) adding} to its set of
85 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tags}.</li>
86 *
87 * <li>{@linkplain com.oracle.truffle.api.instrument.StandardSyntaxTag Standard tags} should
88 * be used for common, language-agnostic concepts such as
89 * {@linkplain com.oracle.truffle.api.instrument.StandardSyntaxTag#STATEMENT STATEMENT}, and this
90 * is usually done by each language's default
91 * {@linkplain com.oracle.truffle.api.instrument.ASTProber ASTProber} while
92 * {@linkplain com.oracle.truffle.api.instrument.Probe Probes} are being created.</li>
93 * <li>{@linkplain com.oracle.truffle.api.instrument.SyntaxTag Tags} serve to configure the behavior
94 * of clients during program execution. For example, knowing which
95 * {@linkplain com.oracle.truffle.api.instrument.Probe Probes} are on
96 * {@linkplain com.oracle.truffle.api.instrument.StandardSyntaxTag#STATEMENT STATEMENT nodes}
97 * informs both the {@linkplain com.oracle.truffle.tools.CoverageTracker code coverage} counter
98 * and the
99 * {@linkplain com.oracle.truffle.api.debug.Debugger debugger} while "stepping".</li>
100 * <li>{@linkplain com.oracle.truffle.api.instrument.SyntaxTag tags} can also be added at any
101 * time by any client for any purpose, including private
102 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag Tags} about which other clients
103 * can learn nothing.</li>
104 * </ul></li>
105 *
106 * <li><strong>Markup Discovery: finding probes</strong>
107 * <ul>
108 * <li>Clients can be observe {@linkplain com.oracle.truffle.api.instrument.Probe Probes}
109 * being {@linkplain com.oracle.truffle.api.instrument.Instrumenter#probe(com.oracle.truffle.api.nodes.Node) created} and
110 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag Tags} being
111 * {@linkplain com.oracle.truffle.api.instrument.Probe#tagAs(SyntaxTag, Object) added} by
112 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#addProbeListener(ProbeListener) registering a
113 * {@linkplain com.oracle.truffle.api.instrument.ProbeListener ProbeListner}.</li>
114 * <li>Clients can also
115 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#findProbesTaggedAs(SyntaxTag) find} all existing
116 * {@linkplain com.oracle.truffle.api.instrument.Probe Probes}, possibly filtering the search by
117 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tag}.</li>
118 * </ul></li>
119 *
120 * <li><strong>Observing Execution: event listening:</strong>
121 * <ul>
122 * <li>Clients can be notified of <em>AST execution events</em> by creating one of several kinds of
123 * <em>event listener</em> and <em>attaching</em> it to a
124 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe}. This creates an
125 * {@linkplain com.oracle.truffle.api.instrument.Instrument Instrument} that notifies the listener
126 * of every subsequent execution event at the AST location corresponding to the
127 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe}.</li>
128 * <li>An
129 * {@linkplain com.oracle.truffle.api.instrument.Instrument Instrument} can be
130 * {@linkplain com.oracle.truffle.api.instrument.Instrument#dispose() disposed}, at which time
131 * it is removed from service at every clone of the AST, incurs no further overhead, and is
132 * permanently unusable.</li>
133 * <li>Many clients need only implement a
134 * {@linkplain com.oracle.truffle.api.instrument.SimpleInstrumentListener SimpleInstrumentListener},
135 * whose notification methods provide only the instance of the
136 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} to which it was attached. This
137 * provides access to the corresponding
138 * {@linkplain com.oracle.truffle.api.SourceSection source code location} and any
139 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tags} that had been applied there.</li>
140 * <li>Clients that require deeper access to execution state implement a
141 * {@linkplain com.oracle.truffle.api.instrument.StandardInstrumentListener StandardInstrumentListener}
142 * whose notification methods provide access to the concrete
143 * {@linkplain com.oracle.truffle.api.nodes.Node AST location} and current
144 * {@linkplain com.oracle.truffle.api.frame.Frame stack frame}.</li>
145 * <li>Clients can also create an
146 * {@linkplain com.oracle.truffle.api.instrument.Instrument Instrument} (whose design is currently
147 * under revision) that supports (effectively) inserting a Truffle AST fragment into the AST
148 * location, where it will be executed subject to full Truffle optimization.</li>
149 * </ul></li>
150 *
151 * <li><strong>Wide-area Instrumentation: traps</strong>
152 * <ul>
153 * <li>A specialized form of Instrumentation is provided that efficiently attaches a single
154 * listener called a
155 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTagTrap tag trap} to every
156 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} containing a specified
157 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tag}.</li>
158 * <li>One (but no more than one)
159 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTagTrap tag trap} may optionally be set
160 * to be notified <em>before</em> every <em>AST execution event</em> where the specified
161 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tag} is present.</li>
162 * <li>One (but no more than one)
163 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTagTrap tag trap} may optionally be set
164 * to be notified <em>after</em> every <em>AST execution event</em> where the specified
165 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTag tag} is present.</li>
166 * <li>The
167 * {@linkplain com.oracle.truffle.api.instrument.SyntaxTagTrap tag trap} mechanism is independent
168 * of listeners that may be attached to
169 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe}. It is especially valuable for
170 * applications such as the debugger, where during "stepping" the program should be halted at
171 * any node tagged with
172 * {@linkplain com.oracle.truffle.api.instrument.StandardSyntaxTag#STATEMENT STATEMENT}.</li>
173 * </ul></li>
174 *
175 * <li><strong>Data Gathering Utilities: tools</strong>
176 * <ul>
177 * <li>The Instrumentation Framework supports extensible set of utilities that can be
178 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter#install(com.oracle.truffle.api.instrument.Instrumenter.Tool)
179 * installed}, at which time they start collecting information that can be queried at any time.</li>
180 * <li>Once installed, these
181 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter.Tool tools} can be dynamically
182 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter.Tool#setEnabled(boolean) disabled and re-enabled} and eventually
183 * {@linkplain com.oracle.truffle.api.instrument.Instrumenter.Tool#dispose() disposed} when no longer needed.</li>
184 * <li>A useful example is the
185 * {@linkplain com.oracle.truffle.tools.LineToProbesMap LineToProbesMap}, which incrementally builds and maintains a map of
186 * {@linkplain com.oracle.truffle.api.instrument.Probe Probes} indexed by
187 * {@linkplain com.oracle.truffle.api.source.LineLocation source code line}. Truffle
188 * {@linkplain com.oracle.truffle.api.debug.Debugger debugging services} depend heavily on this utility.</li>
189 * <li>The
190 * {@linkplain com.oracle.truffle.tools.CoverageTracker CoverageTracker} maintains counts of execution events where a
191 * {@linkplain com.oracle.truffle.api.instrument.Probe Probe} has been tagged with
192 * {@linkplain com.oracle.truffle.api.instrument.StandardSyntaxTag#STATEMENT STATEMENT}, indexed by source code line.</li>
193 * </ul></li>
194 * </ul>
195 *
28 */ 196 */
29 package com.oracle.truffle.api.instrument; 197 package com.oracle.truffle.api.instrument;
30 198