/*
 * Copyright (c) 2013, 2018, 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
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package org.graalvm.compiler.nodes;

import static org.graalvm.compiler.nodeinfo.InputType.State;
import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_UNKNOWN;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_UNKNOWN;

import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.graph.IterableNodeType;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.nodeinfo.NodeInfo;

import jdk.vm.ci.meta.MetaAccessProvider;

/**
 * This node represents an unconditional explicit request for immediate deoptimization.
 *
 * After this node, execution will continue using a fallback execution engine (such as an
 * interpreter) at the position described by the {@link #stateBefore() deoptimization state}.
 */
// @formatter:off
@NodeInfo(cycles = CYCLES_UNKNOWN,
          cyclesRationale = "The cycles for a deopt are as high as possible as we continue execution in the interpreter, " +
                            "but they pollute the cost model, thus we do not care about their cycles.",
          size = SIZE_UNKNOWN,
          sizeRationale = "Deopts carry the meta information necessary to map the state back in the interpreter, but they pollute the cost model," +
                          "thus we do not care about their size.")
// @formatter:on
public abstract class AbstractDeoptimizeNode extends ControlSinkNode implements IterableNodeType, DeoptimizingNode.DeoptBefore {

    public static final NodeClass<AbstractDeoptimizeNode> TYPE = NodeClass.create(AbstractDeoptimizeNode.class);
    @OptionalInput(State) FrameState stateBefore;

    protected AbstractDeoptimizeNode(NodeClass<? extends AbstractDeoptimizeNode> c, FrameState stateBefore) {
        super(c, StampFactory.forVoid());
        this.stateBefore = stateBefore;
    }

    @Override
    public boolean canDeoptimize() {
        return true;
    }

    @Override
    public FrameState stateBefore() {
        return stateBefore;
    }

    @Override
    public void setStateBefore(FrameState f) {
        updateUsages(stateBefore, f);
        stateBefore = f;
    }

    public abstract ValueNode getActionAndReason(MetaAccessProvider metaAccess);

    public abstract ValueNode getSpeculation(MetaAccessProvider metaAccess);
}
