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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.unary;

import java.util.Set;

import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.instrumentation.InstrumentableNode;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.js.nodes.JSGuards;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.access.JSConstantNode;
import com.oracle.truffle.js.nodes.access.JSConstantNode.JSConstantNullNode;
import com.oracle.truffle.js.nodes.access.JSConstantNode.JSConstantUndefinedNode;
import com.oracle.truffle.js.nodes.binary.JSEqualNode;
import com.oracle.truffle.js.nodes.instrumentation.JSTags.BinaryOperationTag;
import com.oracle.truffle.js.runtime.BigInt;
import com.oracle.truffle.js.runtime.JSConfig;
import com.oracle.truffle.js.runtime.SafeInteger;
import com.oracle.truffle.js.runtime.Symbol;
import com.oracle.truffle.js.runtime.objects.JSLazyString;

This node optimizes the check whether the argument is null or undefined. Used from the JSEqualNode for optimizing a == undefined; and a == null; /**
 * This node optimizes the check whether the argument is null or undefined. Used from the
 * {@link JSEqualNode} for optimizing {@code a == undefined;} and {@code a == null;}
 *
 */
@ImportStatic({JSConfig.class})
public abstract class JSIsNullOrUndefinedNode extends JSUnaryNode {
    protected static final int MAX_CLASSES = 3;

    private final boolean isLeft;
    private final boolean isUndefined;

    protected JSIsNullOrUndefinedNode(JavaScriptNode operand, boolean isUndefined, boolean isLeft) {
        super(operand);
        this.isUndefined = isUndefined;
        this.isLeft = isLeft;
    }

    public abstract boolean executeBoolean(Object input);

    @Override
    public boolean hasTag(Class<? extends Tag> tag) {
        if (tag == BinaryOperationTag.class) {
            return true;
        } else {
            return super.hasTag(tag);
        }
    }

    @Override
    public InstrumentableNode materializeInstrumentableNodes(Set<Class<? extends Tag>> materializedTags) {
        if (materializedTags.contains(BinaryOperationTag.class)) {
            JSConstantNode constantNode = isUndefined ? JSConstantNode.createUndefined() : JSConstantNode.createNull();
            JavaScriptNode newOperand = cloneUninitialized(getOperand(), materializedTags);
            JavaScriptNode left = isLeft ? constantNode : newOperand;
            JavaScriptNode right = isLeft ? newOperand : constantNode;
            JavaScriptNode materialized = JSEqualNode.createUnoptimized(left, right);
            transferSourceSectionAddExpressionTag(this, constantNode);
            transferSourceSectionAndTags(this, materialized);
            return materialized;
        } else {
            return this;
        }
    }

    @Specialization(guards = "isJSNull(operand)")
    protected static boolean doNull(@SuppressWarnings("unused") Object operand) {
        return true;
    }

    @Specialization(guards = "isUndefined(operand)")
    protected static boolean doUndefined(@SuppressWarnings("unused") Object operand) {
        return true;
    }

    @Specialization
    protected static boolean doSymbol(@SuppressWarnings("unused") Symbol operand) {
        return false;
    }

    @Specialization
    protected static boolean doLazyString(@SuppressWarnings("unused") JSLazyString operand) {
        return false;
    }

    @Specialization
    protected static boolean doSafeInteger(@SuppressWarnings("unused") SafeInteger operand) {
        return false;
    }

    @Specialization
    protected static boolean doBigInt(@SuppressWarnings("unused") BigInt operand) {
        return false;
    }

    @SuppressWarnings("unused")
    @Specialization(guards = {"cachedClass != null", "cachedClass.isInstance(object)"}, limit = "1")
    protected static boolean doJSObjectCached(Object object,
                    @Cached("getClassIfJSObject(object)") Class<?> cachedClass) {
        assert !JSGuards.isNullOrUndefined(object);
        return false;
    }

    @Specialization(guards = {"isJSObject(object)"}, replaces = {"doJSObjectCached"})
    protected static boolean doJSObject(Object object) {
        assert !JSGuards.isNullOrUndefined(object);
        return false;
    }

    @SuppressWarnings("unused")
    @Specialization(guards = {"operand != null", "cachedClass != null", "cachedClass == operand.getClass()"}, limit = "MAX_CLASSES")
    protected static boolean doJSValueCached(Object operand,
                    @Cached("getNonTruffleObjectClass(operand)") Class<?> cachedClass) {
        return false;
    }

    @Specialization(guards = {"!isTruffleObject(operand)"}, replaces = {"doJSValueCached"})
    protected static boolean doJSValue(@SuppressWarnings("unused") Object operand) {
        return false;
    }

    @Specialization(guards = "isForeignObject(operand)", limit = "InteropLibraryLimit")
    protected boolean doForeign(Object operand,
                    @CachedLibrary("operand") InteropLibrary interop) {
        return interop.isNull(operand);
    }

    public static JSIsNullOrUndefinedNode createFromEquals(JavaScriptNode left, JavaScriptNode right) {
        assert isNullOrUndefined(left) || isNullOrUndefined(right);
        boolean isLeft = isNullOrUndefined(left);
        JavaScriptNode operand = isLeft ? right : left;
        JavaScriptNode constant = isLeft ? left : right;
        boolean isUndefined = constant instanceof JSConstantUndefinedNode;
        return JSIsNullOrUndefinedNodeGen.create(operand, isUndefined, isLeft);
    }

    public static JSIsNullOrUndefinedNode create(JavaScriptNode value) {
        return JSIsNullOrUndefinedNodeGen.create(value, false, false);
    }

    public static JSIsNullOrUndefinedNode create() {
        return JSIsNullOrUndefinedNodeGen.create(null, true, true);
    }

    private static boolean isNullOrUndefined(JavaScriptNode node) {
        return node instanceof JSConstantUndefinedNode || node instanceof JSConstantNullNode;
    }

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return JSIsNullOrUndefinedNodeGen.create(cloneUninitialized(getOperand(), materializedTags), isUndefined, isLeft);
    }
}