001/*
002 * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.nodes.calc;
024
025import jdk.internal.jvmci.common.*;
026import jdk.internal.jvmci.meta.*;
027
028import com.oracle.graal.compiler.common.calc.*;
029import com.oracle.graal.compiler.common.type.*;
030import com.oracle.graal.graph.*;
031import com.oracle.graal.graph.spi.*;
032import com.oracle.graal.nodeinfo.*;
033import com.oracle.graal.nodes.*;
034import com.oracle.graal.nodes.extended.*;
035import com.oracle.graal.nodes.java.*;
036import com.oracle.graal.nodes.spi.*;
037import com.oracle.graal.nodes.virtual.*;
038
039@NodeInfo(shortName = "==")
040public final class ObjectEqualsNode extends PointerEqualsNode implements Virtualizable {
041
042    public static final NodeClass<ObjectEqualsNode> TYPE = NodeClass.create(ObjectEqualsNode.class);
043
044    public ObjectEqualsNode(ValueNode x, ValueNode y) {
045        super(TYPE, x, y);
046        assert x.stamp() instanceof AbstractObjectStamp;
047        assert y.stamp() instanceof AbstractObjectStamp;
048    }
049
050    public static LogicNode create(ValueNode x, ValueNode y, ConstantReflectionProvider constantReflection) {
051        LogicNode result = CompareNode.tryConstantFold(Condition.EQ, x, y, constantReflection, false);
052        if (result != null) {
053            return result;
054        } else {
055            result = findSynonym(x, y);
056            if (result != null) {
057                return result;
058            }
059            return new ObjectEqualsNode(x, y);
060        }
061    }
062
063    @Override
064    protected ValueNode canonicalizeSymmetricConstant(CanonicalizerTool tool, Constant constant, ValueNode nonConstant, boolean mirrored) {
065        ResolvedJavaType type = tool.getConstantReflection().asJavaType(constant);
066        if (type != null && nonConstant instanceof GetClassNode) {
067            if (!type.isPrimitive() && (type.isConcrete() || type.isArray())) {
068                return TypeCheckNode.create(type, ((GetClassNode) nonConstant).getObject());
069            }
070            return LogicConstantNode.forBoolean(false);
071        }
072        return super.canonicalizeSymmetricConstant(tool, constant, nonConstant, mirrored);
073    }
074
075    private void virtualizeNonVirtualComparison(VirtualObjectNode virtual, ValueNode other, VirtualizerTool tool) {
076        if (!virtual.hasIdentity() && virtual.entryKind(0) == Kind.Boolean) {
077            if (other.isConstant()) {
078                JavaConstant otherUnboxed = tool.getConstantReflectionProvider().unboxPrimitive(other.asJavaConstant());
079                if (otherUnboxed != null && otherUnboxed.getKind() == Kind.Boolean) {
080                    int expectedValue = otherUnboxed.asBoolean() ? 1 : 0;
081                    IntegerEqualsNode equals = new IntegerEqualsNode(tool.getEntry(virtual, 0), ConstantNode.forInt(expectedValue, graph()));
082                    tool.addNode(equals);
083                    tool.replaceWithValue(equals);
084                } else {
085                    tool.replaceWithValue(LogicConstantNode.contradiction(graph()));
086                }
087            }
088        } else {
089            // one of them is virtual: they can never be the same objects
090            tool.replaceWithValue(LogicConstantNode.contradiction(graph()));
091        }
092    }
093
094    @Override
095    public void virtualize(VirtualizerTool tool) {
096        ValueNode xAlias = tool.getAlias(getX());
097        ValueNode yAlias = tool.getAlias(getY());
098
099        VirtualObjectNode xVirtual = xAlias instanceof VirtualObjectNode ? (VirtualObjectNode) xAlias : null;
100        VirtualObjectNode yVirtual = yAlias instanceof VirtualObjectNode ? (VirtualObjectNode) yAlias : null;
101
102        if (xVirtual != null && yVirtual == null) {
103            virtualizeNonVirtualComparison(xVirtual, yAlias, tool);
104        } else if (xVirtual == null && yVirtual != null) {
105            virtualizeNonVirtualComparison(yVirtual, xAlias, tool);
106        } else if (xVirtual != null && yVirtual != null) {
107            if (xVirtual.hasIdentity() ^ yVirtual.hasIdentity()) {
108                /*
109                 * One of the two objects has identity, the other doesn't. In code, this looks like
110                 * "Integer.valueOf(a) == new Integer(b)", which is always false.
111                 * 
112                 * In other words: an object created via valueOf can never be equal to one created
113                 * by new in the same compilation unit.
114                 */
115                tool.replaceWithValue(LogicConstantNode.contradiction(graph()));
116            } else if (!xVirtual.hasIdentity() && !yVirtual.hasIdentity()) {
117                ResolvedJavaType type = xVirtual.type();
118                if (type.equals(yVirtual.type())) {
119                    MetaAccessProvider metaAccess = tool.getMetaAccessProvider();
120                    if (type.equals(metaAccess.lookupJavaType(Integer.class)) || type.equals(metaAccess.lookupJavaType(Long.class))) {
121                        // both are virtual without identity: check contents
122                        assert xVirtual.entryCount() == 1 && yVirtual.entryCount() == 1;
123                        assert xVirtual.entryKind(0).getStackKind() == Kind.Int || xVirtual.entryKind(0) == Kind.Long;
124                        IntegerEqualsNode equals = new IntegerEqualsNode(tool.getEntry(xVirtual, 0), tool.getEntry(yVirtual, 0));
125                        tool.addNode(equals);
126                        tool.replaceWithValue(equals);
127                    }
128                }
129            } else {
130                // both are virtual with identity: check if they refer to the same object
131                tool.replaceWithValue(LogicConstantNode.forBoolean(xVirtual == yVirtual, graph()));
132            }
133        }
134    }
135
136    @Override
137    protected CompareNode duplicateModified(ValueNode newX, ValueNode newY) {
138        if (newX.stamp() instanceof ObjectStamp && newY.stamp() instanceof ObjectStamp) {
139            return new ObjectEqualsNode(newX, newY);
140        } else if (newX.stamp() instanceof AbstractPointerStamp && newY.stamp() instanceof AbstractPointerStamp) {
141            return new PointerEqualsNode(newX, newY);
142        }
143        throw JVMCIError.shouldNotReachHere();
144    }
145}