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 * The Universal Permissive License (UPL), Version 1.0
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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package com.oracle.truffle.js.nodes.access;

import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Executed;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.nodes.NodeCost;
import com.oracle.truffle.api.nodes.NodeInfo;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.object.Property;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.profiles.BranchProfile;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.runtime.Errors;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.objects.Dead;
import com.oracle.truffle.js.runtime.objects.JSDynamicObject;

import java.util.Set;

@NodeInfo(cost = NodeCost.NONE)
public class GlobalScopeNode extends JavaScriptNode {
    protected final JSContext context;

    protected GlobalScopeNode(JSContext context) {
        this.context = context;
    }

    public static JavaScriptNode create(JSContext context) {
        return new GlobalScopeNode(context);
    }

    public static JavaScriptNode createWithTDZCheck(JSContext context, String varName) {
        return GlobalScopeTDZCheckNodeGen.create(context, varName);
    }

    @Override
    public Object execute(VirtualFrame frame) {
        return context.getRealm().getGlobalScope();
    }

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return copy();
    }
}

abstract class GlobalScopeTDZCheckNode extends GlobalScopeNode {
    final String varName;
    @Executed @Child JavaScriptNode scopeNode;

    GlobalScopeTDZCheckNode(JSContext context, String varName) {
        super(context);
        this.varName = varName;
        this.scopeNode = GlobalScopeNode.create(context);
    }

    @SuppressWarnings("unused")
    @Specialization(guards = {"scope.getShape() == cachedShape"}, assumptions = {"cachedShape.getValidAssumption()"}, limit = "context.getPropertyCacheLimit()")
    final Object doCached(DynamicObject scope,
                    @Cached("scope.getShape()") Shape cachedShape,
                    @Cached("isDead(cachedShape)") boolean dead) {
        assert dead == (JSDynamicObject.getOrNull(scope, varName) == Dead.instance());
        if (dead) {
            throw Errors.createReferenceErrorNotDefined(context, varName, this);
        }
        return scope;
    }

    @Specialization(replaces = "doCached")
    final Object doUncached(Object scope,
                    @Cached("create(varName, context)") PropertyGetNode getNode,
                    @Cached("create()") BranchProfile deadBranch) {
        if (getNode.getValue(scope) == Dead.instance()) {
            deadBranch.enter();
            throw Errors.createReferenceErrorNotDefined(context, varName, this);
        }
        return scope;
    }

    final boolean isDead(Shape shape) {
        Property property = shape.getProperty(varName);
        return property != null && property.getLocation().isValue() && property.getLocation().get(null) == Dead.instance();
    }

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return GlobalScopeTDZCheckNodeGen.create(context, varName);
    }
}