/*
 * 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.max.graal.nodes;

import com.oracle.max.graal.graph.*;
import com.oracle.max.graal.nodes.calc.*;
import com.oracle.max.graal.nodes.spi.*;
import com.oracle.max.graal.nodes.type.*;

public final class GuardNode extends FloatingNode implements Canonicalizable, LIRLowerable {

    @Input private BooleanNode condition;
    @Input(notDataflow = true) private FixedNode anchor;

    public FixedNode anchor() {
        return anchor;
    }

    public void setAnchor(FixedNode x) {
        updateUsages(anchor, x);
        anchor = x;
    }

    /**
     * The instruction that produces the tested boolean value.
     */
    public BooleanNode condition() {
        return condition;
    }

    public GuardNode(BooleanNode condition, FixedNode anchor) {
        super(StampFactory.illegal());
        this.condition = condition;
        this.anchor = anchor;
    }

    @Override
    public void generate(LIRGeneratorTool gen) {
        gen.emitGuardCheck(condition());
    }

    @Override
    public Node canonical(CanonicalizerTool tool) {
        if (condition() instanceof ConstantNode) {
            ConstantNode c = (ConstantNode) condition();
            if (c.asConstant().asBoolean()) {
                this.replaceAtUsages(null);
                return null;
            }
        }
        return this;
    }
}