Mercurial > hg > graal-compiler
view graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/runtime/SLFunction.java @ 18291:5415422cb32f
Merge.
author | Doug Simon <doug.simon@oracle.com> |
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date | Thu, 06 Nov 2014 20:14:47 +0100 |
parents | 64c77f0577bb |
children | 3286fb5fea4a |
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/* * Copyright (c) 2014, 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. * * 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.sl.runtime; import com.oracle.truffle.api.*; import com.oracle.truffle.api.utilities.*; /** * Represents a SL function. On the Truffle level, a callable element is represented by a * {@link RootCallTarget call target}. This class encapsulates a call target, and adds version * support: functions in SL can be redefined, i.e. changed at run time. When a function is * redefined, the call target managed by this function object is changed (and {@link #callTarget} is * therefore not a final field). * <p> * Function redefinition is expected to be rare, therefore optimized call nodes want to speculate * that the call target is stable. This is possible with the help of a Truffle {@link Assumption}: a * call node can keep the call target returned by {@link #getCallTarget()} cached until the * assumption returned by {@link #getCallTargetStable()} is valid. * <p> * The {@link #callTarget} can be {@code null}. To ensure that only one {@link SLFunction} instance * per name exists, the {@link SLFunctionRegistry} creates an instance also when performing name * lookup. A function that has been looked up, i.e., used, but not defined, has no call target. */ public final class SLFunction { /** The name of the function. */ private final String name; /** The current implementation of this function. */ private RootCallTarget callTarget; /** * Manages the assumption that the {@link #callTarget} is stable. We use the utility class * {@link CyclicAssumption}, which automatically creates a new {@link Assumption} when the old * one gets invalidated. */ private final CyclicAssumption callTargetStable; protected SLFunction(String name) { this.name = name; this.callTargetStable = new CyclicAssumption(name); } public String getName() { return name; } protected void setCallTarget(RootCallTarget callTarget) { this.callTarget = callTarget; /* * We have a new call target. Invalidate all code that speculated that the old call target * was stable. */ callTargetStable.invalidate(); } public RootCallTarget getCallTarget() { return callTarget; } public Assumption getCallTargetStable() { return callTargetStable.getAssumption(); } /** * This method is, e.g., called when using a function literal in a string concatenation. So * changing it has an effect on SL programs. */ @Override public String toString() { return name; } }