Source JS code from https://github.com/mozilla/rhino/issues/379 and it's compiled by Rhino version

SourceScript.java

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

import org.mozilla.javascript.Callable;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.NativeFunction;
import org.mozilla.javascript.Script;
import org.mozilla.javascript.ScriptRuntime;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.Undefined;
import org.mozilla.javascript.optimizer.OptRuntime;

public class SourceScript extends NativeFunction implements Script {
    private static Integer _k0 = 10;
    private static Integer _k1 = 8;
    private int _id;

    public SourceScript(Scriptable var1, Context var2, int var3) {
        this._id = var3;
        switch (var3) {
            case 2:
                this._i2(var2, var1);
                return;
            case 3:
                this._i3(var2, var1);
                return;
            default:
                this._i1(var2, var1);
        }
    }

    public SourceScript() {
        this._id = 0;
    }

    public final Object exec(Context var1, Scriptable var2) {
        return this.call(var1, var2, var2, (Object[]) null);
    }

    public final Object call(Context var1, Scriptable var2, Scriptable var3, Object[] var4) {
        if (!ScriptRuntime.hasTopCall(var1)) {
            return ScriptRuntime.doTopCall(this, var1, var2, var3, var4, false);
        } else {
            switch (this._id) {
                case 1:
                    return ip2long_1(this, var1, var2, var3, var4);
                case 2:
                    return ip2long_2(this, var1, var2, var3, var4);
                case 3:
                    return callback(this, var1, var2, var3, var4);
                default:
                    return _c_script_0(this, var1, var2, var3, var4);
            }
        }
    }

    public int getLanguageVersion() {
        return 200;
    }

    public String getFunctionName() {
        switch (this._id) {
            case 1:
                return "ip2long_1";
            case 2:
                return "ip2long_2";
            case 3:
                return "";
            default:
                return "";
        }
    }

    public int getParamCount() {
        switch (this._id) {
            case 1:
                return 1;
            case 2:
                return 1;
            case 3:
                return 2;
            default:
                return 0;
        }
    }

    public int getParamAndVarCount() {
        switch (this._id) {
            case 1:
                return 4;
            case 2:
                return 1;
            case 3:
                return 2;
            default:
                return 2;
        }
    }

    public String getParamOrVarName(int var1) {
        switch (this._id) {
            case 1:
                switch (var1) {
                    case 1:
                        return "items";
                    case 2:
                        return "result";
                    case 3:
                        return "i";
                    default:
                        return "ipstr";
                }
            case 2:
                return "ipstr";
            case 3:
                switch (var1) {
                    case 1:
                        return "octet";
                    default:
                        return "ipInt";
                }
            default:
                switch (var1) {
                    case 1:
                        return "ip2long_2";
                    default:
                        return "ip2long_1";
                }
        }
    }

    public String getEncodedSource() {
        switch (this._id) {
            case 1:
                return "\u0089n\u0001'\tip2long_1X'\u0005ipstrYV\u0001{'\u0005items['\u0005ipstrm'\u0005splitX)\u0001.YS\u0001{'\u0006result[(S\u0000S\u0001xX{'\u0001i[(S\u0000S'\u0001i\u000e'\u0005itemsm'\u0006lengthS'\u0001ikYV\u0001'\u0006result[X'\u0006result\u0012(S\bY\u0015'\bparseIntX'\u0005itemsT'\u0001iUZ(S\nYS\u0001W\u0001\u0004'\u0006result\u0014(S\u0000S\u0001W§\u0001n\u0001'\tip2long_2X'\u0005ipstrYV\u0001\u0004'\u0005ipstrm'\u0005splitX)\u0001.Ym'\u0006reduceXn\u0002X'\u0005ipIntZ'\u0005octetYV\u0001\u0004X'\u0005ipInt\u0012(S\bY\u0015'\bparseIntX'\u0005octetZ(S\nYS\u0001W§Z(S\u0000Y\u0014(S\u0000S\u0001W§\u0001'\u0005printX'\tip2long_1X)\t127.0.0.1YYS\u0001'\u0005printX'\tip2long_2X)\t127.0.0.1YYS\u0001".substring(1, 182);
            case 2:
                return "\u0089n\u0001'\tip2long_1X'\u0005ipstrYV\u0001{'\u0005items['\u0005ipstrm'\u0005splitX)\u0001.YS\u0001{'\u0006result[(S\u0000S\u0001xX{'\u0001i[(S\u0000S'\u0001i\u000e'\u0005itemsm'\u0006lengthS'\u0001ikYV\u0001'\u0006result[X'\u0006result\u0012(S\bY\u0015'\bparseIntX'\u0005itemsT'\u0001iUZ(S\nYS\u0001W\u0001\u0004'\u0006result\u0014(S\u0000S\u0001W§\u0001n\u0001'\tip2long_2X'\u0005ipstrYV\u0001\u0004'\u0005ipstrm'\u0005splitX)\u0001.Ym'\u0006reduceXn\u0002X'\u0005ipIntZ'\u0005octetYV\u0001\u0004X'\u0005ipInt\u0012(S\bY\u0015'\bparseIntX'\u0005octetZ(S\nYS\u0001W§Z(S\u0000Y\u0014(S\u0000S\u0001W§\u0001'\u0005printX'\tip2long_1X)\t127.0.0.1YYS\u0001'\u0005printX'\tip2long_2X)\t127.0.0.1YYS\u0001".substring(184, 314);
            case 3:
                return "\u0089n\u0001'\tip2long_1X'\u0005ipstrYV\u0001{'\u0005items['\u0005ipstrm'\u0005splitX)\u0001.YS\u0001{'\u0006result[(S\u0000S\u0001xX{'\u0001i[(S\u0000S'\u0001i\u000e'\u0005itemsm'\u0006lengthS'\u0001ikYV\u0001'\u0006result[X'\u0006result\u0012(S\bY\u0015'\bparseIntX'\u0005itemsT'\u0001iUZ(S\nYS\u0001W\u0001\u0004'\u0006result\u0014(S\u0000S\u0001W§\u0001n\u0001'\tip2long_2X'\u0005ipstrYV\u0001\u0004'\u0005ipstrm'\u0005splitX)\u0001.Ym'\u0006reduceXn\u0002X'\u0005ipIntZ'\u0005octetYV\u0001\u0004X'\u0005ipInt\u0012(S\bY\u0015'\bparseIntX'\u0005octetZ(S\nYS\u0001W§Z(S\u0000Y\u0014(S\u0000S\u0001W§\u0001'\u0005printX'\tip2long_1X)\t127.0.0.1YYS\u0001'\u0005printX'\tip2long_2X)\t127.0.0.1YYS\u0001".substring(239, 301);
            default:
                return "\u0089n\u0001'\tip2long_1X'\u0005ipstrYV\u0001{'\u0005items['\u0005ipstrm'\u0005splitX)\u0001.YS\u0001{'\u0006result[(S\u0000S\u0001xX{'\u0001i[(S\u0000S'\u0001i\u000e'\u0005itemsm'\u0006lengthS'\u0001ikYV\u0001'\u0006result[X'\u0006result\u0012(S\bY\u0015'\bparseIntX'\u0005itemsT'\u0001iUZ(S\nYS\u0001W\u0001\u0004'\u0006result\u0014(S\u0000S\u0001W§\u0001n\u0001'\tip2long_2X'\u0005ipstrYV\u0001\u0004'\u0005ipstrm'\u0005splitX)\u0001.Ym'\u0006reduceXn\u0002X'\u0005ipIntZ'\u0005octetYV\u0001\u0004X'\u0005ipInt\u0012(S\bY\u0015'\bparseIntX'\u0005octetZ(S\nYS\u0001W§Z(S\u0000Y\u0014(S\u0000S\u0001W§\u0001'\u0005printX'\tip2long_1X)\t127.0.0.1YYS\u0001'\u0005printX'\tip2long_2X)\t127.0.0.1YYS\u0001".substring(0, 386);
        }
    }

    public boolean getParamOrVarConst(int var1) {
        switch (this._id) {
            case 1:
                switch (var1) {
                    case 1:
                        return false;
                    case 2:
                        return false;
                    case 3:
                        return false;
                    default:
                        return false;
                }
            case 2:
                return false;
            case 3:
                switch (var1) {
                    case 1:
                        return false;
                    default:
                        return false;
                }
            default:
                switch (var1) {
                    case 1:
                        return false;
                    default:
                        return false;
                }
        }
    }

    private final void _i1(Context var1, Scriptable var2) {
        this.initScriptFunction(var1, var2);
    }

    private final void _i2(Context var1, Scriptable var2) {
        this.initScriptFunction(var1, var2);
    }

    private final void _i3(Context var1, Scriptable var2) {
        this.initScriptFunction(var1, var2);
    }

    public static void main(String[] var0) {
        OptRuntime.main(new SourceScript(), var0);
    }

    private static Object _c_script_0(SourceScript var0, Context var1, Scriptable global, Scriptable var3, Object[] var4) {
        ScriptRuntime.initScript(var0, var3, var1, global, false);
        OptRuntime.initFunction(new SourceScript(global, var1, 1), 1, global, var1);
        OptRuntime.initFunction(new SourceScript(global, var1, 2), 1, global, var1);
        Object var5 = Undefined.instance;
        OptRuntime.callName(new Object[]{OptRuntime.callName(new Object[]{"127.0.0.1"}, "ip2long_1", var1, global)}, "print", var1, global);
        var5 = OptRuntime.callName(new Object[]{OptRuntime.callName(new Object[]{"127.0.0.1"}, "ip2long_2", var1, global)}, "print", var1, global);
        return var5;
    }

    private static Object ip2long_1(SourceScript script, Context cx, Scriptable scope, Scriptable var3, Object[] args) {
        scope = script.getParentScope();
        if (args.length < 1) {
            args = ScriptRuntime.padArguments(args, 1);
        }

        Object ipstr = args[0];

        Callable split = ScriptRuntime.getPropFunctionAndThis(ipstr, "split", cx, scope);
        // `items = ipstr.split('.')`
        Object items = OptRuntime.call1(split, ScriptRuntime.lastStoredScriptable(cx), ".", cx, scope);
        Object result = OptRuntime.zeroObj;

        double i = 0.0;
        for (i = 0.0D; i < ScriptRuntime.toNumber(ScriptRuntime.getObjectProp(items, "length", cx, scope)); ++i) {
            // `result << 8`
            double prev = (ScriptRuntime.toInt32(ScriptRuntime.toNumber(result)) << ScriptRuntime.toInt32(8.0D));
            // `items[i]`
            Object itemsElem = ScriptRuntime.getObjectIndex(items, i, cx);
            // `parseInt(items[i], 10)`
            Object next = OptRuntime.callName(new Object[]{itemsElem, _k0}, "parseInt", cx, scope);
            // add and store in `result`
            result = OptRuntime.add(prev, next);
        }

        // final `>>> 0`
        return OptRuntime.wrapDouble((double) (ScriptRuntime.toUint32(result) >>> (ScriptRuntime.toInt32(OptRuntime.zeroObj) & 31)));
    }

    private static Object ip2long_2(SourceScript script, Context cx, Scriptable activation, Scriptable var3, Object[] args) {
        activation = script.getParentScope();
        activation = ScriptRuntime.createFunctionActivation(script, activation, args, false);
        ScriptRuntime.enterActivationFunction(cx, activation);

        Double var10000;
        try {
            // find the `ipstr` in the scope
            Object ipstr = ScriptRuntime.name(cx, activation, "ipstr");
            Callable split = ScriptRuntime.getPropFunctionAndThis(ipstr, "split", cx, activation);
            Scriptable thisObj_ipstr = ScriptRuntime.lastStoredScriptable(cx);
            // result of calling `ipstr.split('.')`
            Object items = OptRuntime.call1(split, thisObj_ipstr, ".", cx, activation);
            Callable reduce = ScriptRuntime.getPropFunctionAndThis(items, "reduce", cx, activation);

            Scriptable thisObj_items = ScriptRuntime.lastStoredScriptable(cx);
            Object result = OptRuntime.call2(
                    reduce, // fn to call
                    thisObj_items, // this
                    new SourceScript(activation, cx, 3), // arg #1: a callback
                    OptRuntime.zeroObj, // arg #2: `0`
                    cx, // context
                    activation // scope
            );

            // final `>>> 0`
            var10000 = OptRuntime.wrapDouble((double) (ScriptRuntime.toUint32(result) >>> (ScriptRuntime.toInt32(OptRuntime.zeroObj) & 31)));
        } finally {
            ScriptRuntime.exitActivationFunction(cx);
        }

        return var10000;
    }

    private static Object callback(SourceScript script, Context cx, Scriptable scope, Scriptable var3, Object[] args) {
        scope = script.getParentScope();
        if (args.length < 2) {
            args = ScriptRuntime.padArguments(args, 2);
        }

        Object ipInt = args[0];
        Object octet = args[1];
        // `ipInt << 8`
        Double result = OptRuntime.wrapDouble((double) (ScriptRuntime.toInt32(ipInt) << ScriptRuntime.toInt32(_k1)));
        // `parseInt(octet, 10)`
        Object parseInt_result = OptRuntime.callName(new Object[]{octet, _k0}, "parseInt", cx, scope);

        // add and return
        return ScriptRuntime.add(result, parseInt_result, cx);
    }
}

SourceScript.js

function ip2long_1(ipstr) {
        var items  = ipstr.split('.')
        var result = 0

        for (var i = 0; i < items.length; i ++) {
                    result = (result << 8) + parseInt(items[i], 10)
                }
        return result >>> 0
}

function ip2long_2(ipstr) {
       return ipstr.split('.').reduce(function(ipInt, octet) { return (ipInt<<8) + parseInt(octet, 10)}, 0) >>> 0;
}

print(ip2long_2('127.0.0.1'));
print(ip2long_1('127.0.0.1'));

// to generate Java bytecode
// $ java -classpath rhino-1.7.8-SNAPSHOT.jar org.mozilla.javascript.tools.jsc.Main -version 200 -opt 9 -debug SourceScript.js