001/*
002 * Copyright (c) 2012, 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.replacements.nodes;
024
025import jdk.internal.jvmci.code.*;
026import jdk.internal.jvmci.meta.*;
027
028import com.oracle.graal.compiler.common.type.*;
029import com.oracle.graal.graph.*;
030import com.oracle.graal.nodeinfo.*;
031import com.oracle.graal.nodes.*;
032import com.oracle.graal.nodes.spi.*;
033
034/**
035 * Access the value of a specific register.
036 */
037@NodeInfo(nameTemplate = "ReadRegister %{p#register}")
038public final class ReadRegisterNode extends FixedWithNextNode implements LIRLowerable {
039
040    public static final NodeClass<ReadRegisterNode> TYPE = NodeClass.create(ReadRegisterNode.class);
041    /**
042     * The fixed register to access.
043     */
044    protected final Register register;
045
046    /**
047     * When true, subsequent uses of this node use the fixed register; when false, the value is
048     * moved into a new virtual register so that the fixed register is not seen by uses.
049     */
050    protected final boolean directUse;
051
052    /**
053     * When true, this node is also an implicit definition of the value for the register allocator,
054     * i.e., the register is an implicit incoming value; when false, the register must be defined in
055     * the same method or must be an register excluded from register allocation.
056     */
057    protected final boolean incoming;
058
059    public ReadRegisterNode(Register register, Kind kind, boolean directUse, boolean incoming) {
060        super(TYPE, StampFactory.forKind(kind));
061        assert register != null;
062        this.register = register;
063        this.directUse = directUse;
064        this.incoming = incoming;
065    }
066
067    public ReadRegisterNode(Register register, boolean directUse, boolean incoming) {
068        super(TYPE, StampFactory.forNodeIntrinsic());
069        assert register != null;
070        this.register = register;
071        this.directUse = directUse;
072        this.incoming = incoming;
073    }
074
075    @Override
076    public void generate(NodeLIRBuilderTool generator) {
077        LIRKind kind = generator.getLIRGeneratorTool().getLIRKind(stamp());
078        Value result = register.asValue(kind);
079        if (incoming) {
080            generator.getLIRGeneratorTool().emitIncomingValues(new Value[]{result});
081        }
082        if (!directUse) {
083            result = generator.getLIRGeneratorTool().emitMove(result);
084        }
085        generator.setResult(this, result);
086    }
087
088    @Override
089    public String toString(Verbosity verbosity) {
090        if (verbosity == Verbosity.Name) {
091            return super.toString(Verbosity.Name) + "%" + register;
092        } else {
093            return super.toString(verbosity);
094        }
095    }
096}