Mercurial > hg > graal-compiler
view graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/call/SLDirectDispatchNode.java @ 19312:a8d128366ebf
Merge
author | Andreas Woess <andreas.woess@jku.at> |
---|---|
date | Thu, 12 Feb 2015 04:01:46 +0100 |
parents | 04703cff4ef2 |
children |
line wrap: on
line source
/* * 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. * * 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.nodes.call; import com.oracle.truffle.api.*; import com.oracle.truffle.api.frame.*; import com.oracle.truffle.api.nodes.*; import com.oracle.truffle.sl.runtime.*; /** * An entry in the polymorphic inline cache. */ final class SLDirectDispatchNode extends SLAbstractDispatchNode { /** The cached function. */ private final SLFunction cachedFunction; /** * {@link DirectCallNode} is part of the Truffle API and handles all the steps necessary for * method inlining: if the call is executed frequently and the callee is small, then the call is * inlined, i.e., the call node is replaced with a copy of the callee's AST. */ @Child private DirectCallNode callCachedTargetNode; /** Assumption that the {@link #callCachedTargetNode} is still valid. */ private final Assumption cachedTargetStable; /** * The next entry of the polymorphic inline cache, either another {@link SLDirectDispatchNode} * or a {@link SLUninitializedDispatchNode}. */ @Child private SLAbstractDispatchNode nextNode; protected SLDirectDispatchNode(SLAbstractDispatchNode next, SLFunction cachedFunction) { this.cachedFunction = cachedFunction; this.callCachedTargetNode = Truffle.getRuntime().createDirectCallNode(cachedFunction.getCallTarget()); this.cachedTargetStable = cachedFunction.getCallTargetStable(); this.nextNode = next; } /** * Perform the inline cache check. If it succeeds, execute the cached * {@link #cachedTargetStable call target}; if it fails, defer to the next element in the chain. * <p> * Since SL is a quite simple language, the benefit of the inline cache is quite small: after * checking that the actual function to be executed is the same as the * {@link SLDirectDispatchNode#cachedFunction}, we can safely execute the cached call target. * You can reasonably argue that caching the call target is overkill, since we could just * retrieve it via {@code function.getCallTarget()}. However, in a more complex language the * lookup of the call target is usually much more complicated than in SL. In addition, caching * the call target allows method inlining. */ @Override protected Object executeDispatch(VirtualFrame frame, SLFunction function, Object[] arguments) { /* * The inline cache check. Note that cachedFunction must be a final field so that the * compiler can optimize the check. */ if (this.cachedFunction == function) { /* Inline cache hit, we are safe to execute the cached call target. */ try { /* * Support for function redefinition: When a function is redefined, the call target * maintained by the SLFunction object is change. To avoid a check for that, we use * an Assumption that is invalidated by the SLFunction when the change is performed. * Since checking an assumption is a no-op in compiled code, the line below does not * add any overhead during optimized execution. */ cachedTargetStable.check(); /* * Now we are really ready to perform the call. We use a Truffle CallNode for that, * because it does all the work for method inlining. */ return callCachedTargetNode.call(frame, arguments); } catch (InvalidAssumptionException ex) { /* * The function has been redefined. Remove ourself from the polymorphic inline * cache, so that we fail the check only once. Note that this replacement has subtle * semantics: we are changing a node in the tree that is currently executed. This is * only safe because we know that after the call to replace(), there is no more code * that requires that this node is part of the tree. */ replace(nextNode); /* Execute the next node in the chain by falling out of the if block. */ } } /* Inline cache miss, defer to the next element in the chain. */ return nextNode.executeDispatch(frame, function, arguments); } }