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view graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Instrument.java @ 16961:a1427e40deaf
Truffle/Instrumentation: some Javadoc revistions; minor code cleanups; remove one redundant operation; add tracing to the LineLocation maps.
author | Michael Van De Vanter <michael.van.de.vanter@oracle.com> |
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date | Tue, 26 Aug 2014 13:54:53 -0700 |
parents | 8c34e2cc4add |
children | b4e38f4ca414 |
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/* * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.truffle.api.instrument; import com.oracle.truffle.api.CompilerDirectives.CompilationFinal; import com.oracle.truffle.api.CompilerDirectives.SlowPath; import com.oracle.truffle.api.frame.*; import com.oracle.truffle.api.instrument.impl.*; import com.oracle.truffle.api.nodes.*; /** * A receiver of Truffle AST runtime {@link ExecutionEvents}, propagated from the {@link Probe} to * which the instrument is attached, for the benefit of associated <em>tools</em>. * <p> * Guidelines for implementing {@link Instrument}s, with particular attention to minimize runtime * performance overhead: * <ol> * <li>Extend this abstract class and override only the {@linkplain ExecutionEvents event handling * methods} for which intervention is needed.</li> * <li>Instruments are Truffle {@link Node}s and should be coded as much as possible in the desired * <em>Truffle style</em>, documented more thoroughly elsewhere.</li> * <li>Maintain as little state as possible.</li> * <li>If state is necessary, make object fields {@code final} if at all possible.</li> * <li>If non-final object-valued state is necessary, annotate it as {@link CompilationFinal} and * call {@linkplain InstrumentationNode#notifyProbeChanged(Instrument)} whenever it is modified.</li> * <li>Never store a {@link Frame} value in a field.</li> * <li>Minimize computation in standard execution paths.</li> * <li>If runtime calls must be made back to a tool, construct the instrument with a callback stored * in a {@code final} field.</li> * <li>Tool methods called by the instrument should be annotated as {@link SlowPath} to prevent them * from being inlined into fast execution paths.</li> * <li>If computation in the execution path is needed, and if performance is important, then the * computation is best expressed as a guest language AST and evaluated using standard Truffle * mechanisms so that standard Truffle optimizations can be applied.</li> * </ol> * <p> * Guidelines for attachment to a {@link Probe}: * <ol> * <li>An Instrument instance must only attached to a single {@link Probe}, each of which is * associated uniquely with a specific syntactic unit of a guest language program, and thus * (initially) to a specific {@linkplain Node Truffle AST node}.</li> * <li>When the AST containing such a node is copied at runtime, the {@link Probe} will be shared by * every copy, and so the Instrument will receive events corresponding to the intended syntactic * unit of code, independent of which AST copy is being executed.</li> * </ol> * <p> * Guidelines for handling {@link ExecutionEvents}: * <ol> * <li>Separate event methods are defined for each kind of possible return: object-valued, * primitive-valued, void-valued, and exceptional.</li> * <li>Override "leave*" primitive methods if the language implementation returns primitives and the * instrument should avoid boxing them.</li> * <li>On the other hand, if boxing all primitives for instrumentation is desired, it is only * necessary to override the object-valued return methods, since the default implementation of each * primitive-valued return method is to box the value and forward it to the object-valued return * method.</li> * </ol> * * <p> * <strong>Disclaimer:</strong> experimental; under development. * * @see Probe * @see ASTNodeProber */ public abstract class Instrument extends InstrumentationNode { protected Instrument() { } public void enter(Node astNode, VirtualFrame frame) { } public void leave(Node astNode, VirtualFrame frame) { } public void leave(Node astNode, VirtualFrame frame, boolean result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, byte result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, short result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, int result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, long result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, char result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, float result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, double result) { leave(astNode, frame, (Object) result); } public void leave(Node astNode, VirtualFrame frame, Object result) { } public void leaveExceptional(Node astNode, VirtualFrame frame, Exception e) { } }