Mercurial > hg > graal-compiler
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/calc/IsNullNode.java @ 18490:ca81508f2a19
Generalize NULL handling to work on arbitrary pointers.
author | Roland Schatz <roland.schatz@oracle.com> |
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date | Mon, 24 Nov 2014 13:53:14 +0100 |
parents | 9619ba4daf4c |
children | f57d86eb036f |
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/* * Copyright (c) 2009, 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.graal.nodes.calc; import com.oracle.graal.compiler.common.type.*; import com.oracle.graal.graph.spi.*; import com.oracle.graal.nodeinfo.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.nodes.type.*; /** * An IsNullNode will be true if the supplied value is null, and false if it is non-null. */ @NodeInfo public class IsNullNode extends UnaryOpLogicNode implements LIRLowerable, Virtualizable, PiPushable { /** * Constructs a new IsNullNode instruction. * * @param object the instruction producing the object to check against null */ public static IsNullNode create(ValueNode object) { return new IsNullNode(object); } protected IsNullNode(ValueNode object) { super(object); } @Override public void generate(NodeLIRBuilderTool gen) { // Nothing to do. } @Override public boolean verify() { assertTrue(getValue() != null, "is null input must not be null"); assertTrue(getValue().stamp() instanceof AbstractPointerStamp, "is null input must be a pointer"); return super.verify(); } @Override public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) { if (StampTool.isPointerAlwaysNull(forValue)) { return LogicConstantNode.tautology(); } else if (StampTool.isPointerNonNull(forValue)) { return LogicConstantNode.contradiction(); } return this; } @Override public void virtualize(VirtualizerTool tool) { if (tool.getObjectState(getValue()) != null) { tool.replaceWithValue(LogicConstantNode.contradiction(graph())); } } @Override public boolean push(PiNode parent) { if (parent.stamp() instanceof ObjectStamp && parent.object().stamp() instanceof ObjectStamp) { ObjectStamp piStamp = (ObjectStamp) parent.stamp(); ObjectStamp piValueStamp = (ObjectStamp) parent.object().stamp(); if (piStamp.nonNull() == piValueStamp.nonNull() && piStamp.alwaysNull() == piValueStamp.alwaysNull()) { replaceFirstInput(parent, parent.object()); return true; } } return false; } @NodeIntrinsic public static native IsNullNode isNull(Object object); }