Mercurial > hg > graal-jvmci-8
view graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/ReadEliminationPhase.java @ 6307:d7f67808f970
Create ValueProxy nodes where necessary during ReadElimination
author | Gilles Duboscq <duboscq@ssw.jku.at> |
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date | Mon, 03 Sep 2012 12:52:22 +0200 |
parents | d6257bd5e7f2 |
children | 9b017f213df8 |
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/* * Copyright (c) 2011, 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.graal.compiler.phases; import java.util.*; import com.oracle.graal.debug.*; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.PhiNode.PhiType; import com.oracle.graal.nodes.extended.*; public class ReadEliminationPhase extends Phase { private Queue<PhiNode> newPhis; @Override protected void run(StructuredGraph graph) { newPhis = new LinkedList<>(); for (FloatingReadNode n : graph.getNodes(FloatingReadNode.class)) { if (isReadEliminable(n)) { NodeMap<ValueNode> nodeMap = n.graph().createNodeMap(); ValueNode value = getValue(n, n.lastLocationAccess(), nodeMap); Debug.log("Eliminated memory read %1.1s and replaced with node %s", n, value); graph.replaceFloating(n, value); } } } private boolean isReadEliminable(FloatingReadNode n) { return isWrites(n, n.lastLocationAccess(), n.graph().createNodeBitMap()); } private boolean isWrites(FloatingReadNode n, Node lastLocationAccess, NodeBitMap visited) { if (lastLocationAccess == null) { return false; } if (visited.isMarked(lastLocationAccess)) { return true; // dataflow loops must come from Phis assume them ok until proven wrong } if (lastLocationAccess instanceof ValueProxyNode) { return isWrites(n, ((ValueProxyNode) lastLocationAccess).value(), visited); } if (lastLocationAccess instanceof WriteNode) { WriteNode other = (WriteNode) lastLocationAccess; return other.object() == n.object() && other.location() == n.location(); } if (lastLocationAccess instanceof PhiNode) { visited.mark(lastLocationAccess); for (ValueNode value : ((PhiNode) lastLocationAccess).values()) { if (!isWrites(n, value, visited)) { return false; } } return true; } return false; } private ValueNode getValue(FloatingReadNode n, Node lastLocationAccess, NodeMap<ValueNode> nodeMap) { ValueNode exisiting = nodeMap.get(lastLocationAccess); if (exisiting != null) { return exisiting; } if (lastLocationAccess instanceof ValueProxyNode) { ValueProxyNode proxy = (ValueProxyNode) lastLocationAccess; ValueNode value = getValue(n, proxy.value(), nodeMap); assert proxy.type() == PhiType.Value; return lastLocationAccess.graph().add(new ValueProxyNode(value, proxy.proxyPoint(), PhiType.Value)); } if (lastLocationAccess instanceof WriteNode) { return ((WriteNode) lastLocationAccess).value(); } if (lastLocationAccess instanceof PhiNode) { PhiNode phi = (PhiNode) lastLocationAccess; PhiNode newPhi = phi.graph().add(new PhiNode(n.kind(), phi.merge())); nodeMap.set(lastLocationAccess, newPhi); for (ValueNode value : phi.values()) { newPhi.addInput(getValue(n, value, nodeMap)); } newPhis.add(newPhi); return newPhi; } throw GraalInternalError.shouldNotReachHere(); } }