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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 * accompanied this code).
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package org.graalvm.compiler.hotspot.replacements;

import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.spi.Canonicalizable;
import org.graalvm.compiler.graph.spi.CanonicalizerTool;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.InvokeNode;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.spi.Lowerable;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.replacements.nodes.MacroStateSplitNode;

import jdk.vm.ci.hotspot.HotSpotObjectConstant;
import jdk.vm.ci.meta.Assumptions;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.MetaAccessProvider;

@NodeInfo
public final class CallSiteTargetNode extends MacroStateSplitNode implements Canonicalizable, Lowerable {

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

    public CallSiteTargetNode(MacroParams p) {
        super(TYPE, p);
    }

    private ValueNode getCallSite() {
        return arguments.get(0);
    }

    public static ConstantNode tryFold(ValueNode callSite, MetaAccessProvider metaAccess, Assumptions assumptions) {
        if (callSite != null && callSite.isConstant() && !callSite.isNullConstant()) {
            HotSpotObjectConstant c = (HotSpotObjectConstant) callSite.asConstant();
            JavaConstant target = c.getCallSiteTarget(assumptions);
            if (target != null) {
                return ConstantNode.forConstant(target, metaAccess);
            }
        }
        return null;
    }

    @Override
    public Node canonical(CanonicalizerTool tool) {
        ConstantNode target = tryFold(getCallSite(), tool.getMetaAccess(), graph().getAssumptions());
        if (target != null) {
            return target;
        }

        return this;
    }

    @Override
    public void lower(LoweringTool tool) {
        ConstantNode target = tryFold(getCallSite(), tool.getMetaAccess(), graph().getAssumptions());

        if (target != null) {
            graph().replaceFixedWithFloating(this, target);
        } else {
            InvokeNode invoke = createInvoke();
            graph().replaceFixedWithFixed(this, invoke);
            invoke.lower(tool);
        }
    }
}