/*

 * Copyright (c) 2012, 2019, 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 org.graalvm.compiler.replacements.nodes;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;

import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;

import org.graalvm.compiler.core.common.LIRKind;

import org.graalvm.compiler.core.common.type.Stamp;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodeinfo.Verbosity;

import org.graalvm.compiler.nodes.FixedWithNextNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.spi.LIRLowerable;

import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.Value;

/**

 * Access the value of a specific register.

 */

@NodeInfo(nameTemplate = "ReadRegister %{p#register}", cycles = CYCLES_0, size = SIZE_0)

public final class ReadRegisterNode extends FixedWithNextNode implements LIRLowerable {

    public static final NodeClass<ReadRegisterNode> TYPE = NodeClass.create(ReadRegisterNode.class);

    /**

     * The fixed register to access.

     */

    protected final Register register;

    /**

     * When true, subsequent uses of this node use the fixed register; when false, the value is

     * moved into a new virtual register so that the fixed register is not seen by uses.

     */

    protected final boolean directUse;

    /**

     * When true, this node is also an implicit definition of the value for the register allocator,

     * i.e., the register is an implicit incoming value; when false, the register must be defined in

     * the same method or must be an register excluded from register allocation.

     */

    protected final boolean incoming;

    public ReadRegisterNode(Register register, JavaKind kind, boolean directUse, boolean incoming) {

        super(TYPE, StampFactory.forKind(kind));

        assert register != null;

        this.register = register;

        this.directUse = directUse;

        this.incoming = incoming;

    }

    public ReadRegisterNode(@InjectedNodeParameter Stamp stamp, Register register, boolean directUse, boolean incoming) {

        super(TYPE, stamp);

        assert register != null;

        this.register = register;

        this.directUse = directUse;

        this.incoming = incoming;

    }

    @Override

    public void generate(NodeLIRBuilderTool generator) {

        LIRKind kind = generator.getLIRGeneratorTool().getLIRKind(stamp(NodeView.DEFAULT));

        Value result = register.asValue(kind);

        if (incoming) {

            generator.getLIRGeneratorTool().emitIncomingValues(new Value[]{result});

        }

        if (!directUse) {

            result = generator.getLIRGeneratorTool().emitReadRegister(register, kind);

        }

        generator.setResult(this, result);

    }

    @Override

    public String toString(Verbosity verbosity) {

        if (verbosity == Verbosity.Name) {

            return super.toString(Verbosity.Name) + "%" + register;

        } else {

            return super.toString(verbosity);

        }

    }

}