deleted file mode 100644
--- a/js/src/builtin/intl/LangTagMappingsGenerated.js
+++ /dev/null
@@ -1,1209 +0,0 @@
-// Generated by make_intl_data.py. DO NOT EDIT.
-
-// Mappings from grandfathered tags to preferred values.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-var grandfatheredMappings = {
-    "art-lojban": "jbo",
-    "cel-gaulish": "xtg-x-cel-gaulish",
-    "zh-guoyu": "zh",
-    "zh-hakka": "hak",
-    "zh-xiang": "hsn",
-};
-
-// Mappings from language subtags to preferred values.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-var languageMappings = {
-    "aam": "aas",
-    "aar": "aa",
-    "abk": "ab",
-    "adp": "dz",
-    "afr": "af",
-    "aju": "jrb",
-    "aka": "ak",
-    "alb": "sq",
-    "als": "sq",
-    "amh": "am",
-    "ara": "ar",
-    "arb": "ar",
-    "arg": "an",
-    "arm": "hy",
-    "asm": "as",
-    "aue": "ktz",
-    "ava": "av",
-    "ave": "ae",
-    "aym": "ay",
-    "ayr": "ay",
-    "ayx": "nun",
-    "aze": "az",
-    "azj": "az",
-    "bak": "ba",
-    "bam": "bm",
-    "baq": "eu",
-    "bcc": "bal",
-    "bcl": "bik",
-    "bel": "be",
-    "ben": "bn",
-    "bgm": "bcg",
-    "bh": "bho",
-    "bih": "bho",
-    "bis": "bi",
-    "bjd": "drl",
-    "bod": "bo",
-    "bos": "bs",
-    "bre": "br",
-    "bul": "bg",
-    "bur": "my",
-    "bxk": "luy",
-    "bxr": "bua",
-    "cat": "ca",
-    "ccq": "rki",
-    "ces": "cs",
-    "cha": "ch",
-    "che": "ce",
-    "chi": "zh",
-    "chu": "cu",
-    "chv": "cv",
-    "cjr": "mom",
-    "cka": "cmr",
-    "cld": "syr",
-    "cmk": "xch",
-    "cmn": "zh",
-    "cor": "kw",
-    "cos": "co",
-    "coy": "pij",
-    "cqu": "quh",
-    "cre": "cr",
-    "cwd": "cr",
-    "cym": "cy",
-    "cze": "cs",
-    "dan": "da",
-    "deu": "de",
-    "dgo": "doi",
-    "dhd": "mwr",
-    "dik": "din",
-    "diq": "zza",
-    "div": "dv",
-    "drh": "mn",
-    "dut": "nl",
-    "dzo": "dz",
-    "ekk": "et",
-    "ell": "el",
-    "emk": "man",
-    "eng": "en",
-    "epo": "eo",
-    "esk": "ik",
-    "est": "et",
-    "eus": "eu",
-    "ewe": "ee",
-    "fao": "fo",
-    "fas": "fa",
-    "fat": "ak",
-    "fij": "fj",
-    "fin": "fi",
-    "fra": "fr",
-    "fre": "fr",
-    "fry": "fy",
-    "fuc": "ff",
-    "ful": "ff",
-    "gav": "dev",
-    "gaz": "om",
-    "gbo": "grb",
-    "geo": "ka",
-    "ger": "de",
-    "gfx": "vaj",
-    "ggn": "gvr",
-    "gla": "gd",
-    "gle": "ga",
-    "glg": "gl",
-    "glv": "gv",
-    "gno": "gon",
-    "gre": "el",
-    "grn": "gn",
-    "gti": "nyc",
-    "gug": "gn",
-    "guj": "gu",
-    "guv": "duz",
-    "gya": "gba",
-    "hat": "ht",
-    "hau": "ha",
-    "hdn": "hai",
-    "hea": "hmn",
-    "heb": "he",
-    "her": "hz",
-    "him": "srx",
-    "hin": "hi",
-    "hmo": "ho",
-    "hrr": "jal",
-    "hrv": "hr",
-    "hun": "hu",
-    "hye": "hy",
-    "ibi": "opa",
-    "ibo": "ig",
-    "ice": "is",
-    "ido": "io",
-    "iii": "ii",
-    "ike": "iu",
-    "iku": "iu",
-    "ile": "ie",
-    "ilw": "gal",
-    "in": "id",
-    "ina": "ia",
-    "ind": "id",
-    "ipk": "ik",
-    "isl": "is",
-    "ita": "it",
-    "iw": "he",
-    "jav": "jv",
-    "jeg": "oyb",
-    "ji": "yi",
-    "jpn": "ja",
-    "jw": "jv",
-    "kal": "kl",
-    "kan": "kn",
-    "kas": "ks",
-    "kat": "ka",
-    "kau": "kr",
-    "kaz": "kk",
-    "kgc": "tdf",
-    "kgh": "kml",
-    "khk": "mn",
-    "khm": "km",
-    "kik": "ki",
-    "kin": "rw",
-    "kir": "ky",
-    "kmr": "ku",
-    "knc": "kr",
-    "kng": "kg",
-    "knn": "kok",
-    "koj": "kwv",
-    "kom": "kv",
-    "kon": "kg",
-    "kor": "ko",
-    "kpv": "kv",
-    "krm": "bmf",
-    "ktr": "dtp",
-    "kua": "kj",
-    "kur": "ku",
-    "kvs": "gdj",
-    "kwq": "yam",
-    "kxe": "tvd",
-    "kzj": "dtp",
-    "kzt": "dtp",
-    "lao": "lo",
-    "lat": "la",
-    "lav": "lv",
-    "lbk": "bnc",
-    "lii": "raq",
-    "lim": "li",
-    "lin": "ln",
-    "lit": "lt",
-    "lmm": "rmx",
-    "ltz": "lb",
-    "lub": "lu",
-    "lug": "lg",
-    "lvs": "lv",
-    "mac": "mk",
-    "mah": "mh",
-    "mal": "ml",
-    "mao": "mi",
-    "mar": "mr",
-    "may": "ms",
-    "meg": "cir",
-    "mhr": "chm",
-    "mkd": "mk",
-    "mlg": "mg",
-    "mlt": "mt",
-    "mnk": "man",
-    "mo": "ro",
-    "mol": "ro",
-    "mon": "mn",
-    "mri": "mi",
-    "msa": "ms",
-    "mst": "mry",
-    "mup": "raj",
-    "mwj": "vaj",
-    "mya": "my",
-    "myt": "mry",
-    "nad": "xny",
-    "nau": "na",
-    "nav": "nv",
-    "nbl": "nr",
-    "ncp": "kdz",
-    "nde": "nd",
-    "ndo": "ng",
-    "nep": "ne",
-    "nld": "nl",
-    "nno": "nn",
-    "nnx": "ngv",
-    "no": "nb",
-    "nob": "nb",
-    "nor": "nb",
-    "npi": "ne",
-    "nts": "pij",
-    "nya": "ny",
-    "oci": "oc",
-    "ojg": "oj",
-    "oji": "oj",
-    "ori": "or",
-    "orm": "om",
-    "ory": "or",
-    "oss": "os",
-    "oun": "vaj",
-    "pan": "pa",
-    "pbu": "ps",
-    "pcr": "adx",
-    "per": "fa",
-    "pes": "fa",
-    "pli": "pi",
-    "plt": "mg",
-    "pmc": "huw",
-    "pmu": "phr",
-    "pnb": "lah",
-    "pol": "pl",
-    "por": "pt",
-    "ppa": "bfy",
-    "ppr": "lcq",
-    "pry": "prt",
-    "pus": "ps",
-    "puz": "pub",
-    "que": "qu",
-    "quz": "qu",
-    "rmy": "rom",
-    "roh": "rm",
-    "ron": "ro",
-    "rum": "ro",
-    "run": "rn",
-    "rus": "ru",
-    "sag": "sg",
-    "san": "sa",
-    "sca": "hle",
-    "scc": "sr",
-    "scr": "hr",
-    "sin": "si",
-    "skk": "oyb",
-    "slk": "sk",
-    "slo": "sk",
-    "slv": "sl",
-    "sme": "se",
-    "smo": "sm",
-    "sna": "sn",
-    "snd": "sd",
-    "som": "so",
-    "sot": "st",
-    "spa": "es",
-    "spy": "kln",
-    "sqi": "sq",
-    "src": "sc",
-    "srd": "sc",
-    "srp": "sr",
-    "ssw": "ss",
-    "sun": "su",
-    "swa": "sw",
-    "swe": "sv",
-    "swh": "sw",
-    "tah": "ty",
-    "tam": "ta",
-    "tat": "tt",
-    "tdu": "dtp",
-    "tel": "te",
-    "tgk": "tg",
-    "tgl": "fil",
-    "tha": "th",
-    "thc": "tpo",
-    "thx": "oyb",
-    "tib": "bo",
-    "tie": "ras",
-    "tir": "ti",
-    "tkk": "twm",
-    "tl": "fil",
-    "tlw": "weo",
-    "tmp": "tyj",
-    "tne": "kak",
-    "ton": "to",
-    "tsf": "taj",
-    "tsn": "tn",
-    "tso": "ts",
-    "ttq": "tmh",
-    "tuk": "tk",
-    "tur": "tr",
-    "tw": "ak",
-    "twi": "ak",
-    "uig": "ug",
-    "ukr": "uk",
-    "umu": "del",
-    "uok": "ema",
-    "urd": "ur",
-    "uzb": "uz",
-    "uzn": "uz",
-    "ven": "ve",
-    "vie": "vi",
-    "vol": "vo",
-    "wel": "cy",
-    "wln": "wa",
-    "wol": "wo",
-    "xba": "cax",
-    "xho": "xh",
-    "xia": "acn",
-    "xkh": "waw",
-    "xpe": "kpe",
-    "xsj": "suj",
-    "xsl": "den",
-    "ybd": "rki",
-    "ydd": "yi",
-    "yid": "yi",
-    "yma": "lrr",
-    "ymt": "mtm",
-    "yor": "yo",
-    "yos": "zom",
-    "yuu": "yug",
-    "zai": "zap",
-    "zha": "za",
-    "zho": "zh",
-    "zsm": "ms",
-    "zul": "zu",
-    "zyb": "za",
-};
-
-// Language subtags with complex mappings.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-var complexLanguageMappings = {
-    "cnr": true,
-    "drw": true,
-    "hbs": true,
-    "prs": true,
-    "sh": true,
-    "swc": true,
-    "tnf": true,
-};
-
-// Mappings from region subtags to preferred values.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-var regionMappings = {
-    "004": "AF",
-    "008": "AL",
-    "010": "AQ",
-    "012": "DZ",
-    "016": "AS",
-    "020": "AD",
-    "024": "AO",
-    "028": "AG",
-    "031": "AZ",
-    "032": "AR",
-    "036": "AU",
-    "040": "AT",
-    "044": "BS",
-    "048": "BH",
-    "050": "BD",
-    "051": "AM",
-    "052": "BB",
-    "056": "BE",
-    "060": "BM",
-    "062": "034",
-    "064": "BT",
-    "068": "BO",
-    "070": "BA",
-    "072": "BW",
-    "074": "BV",
-    "076": "BR",
-    "084": "BZ",
-    "086": "IO",
-    "090": "SB",
-    "092": "VG",
-    "096": "BN",
-    "100": "BG",
-    "104": "MM",
-    "108": "BI",
-    "112": "BY",
-    "116": "KH",
-    "120": "CM",
-    "124": "CA",
-    "132": "CV",
-    "136": "KY",
-    "140": "CF",
-    "144": "LK",
-    "148": "TD",
-    "152": "CL",
-    "156": "CN",
-    "158": "TW",
-    "162": "CX",
-    "166": "CC",
-    "170": "CO",
-    "174": "KM",
-    "175": "YT",
-    "178": "CG",
-    "180": "CD",
-    "184": "CK",
-    "188": "CR",
-    "191": "HR",
-    "192": "CU",
-    "196": "CY",
-    "203": "CZ",
-    "204": "BJ",
-    "208": "DK",
-    "212": "DM",
-    "214": "DO",
-    "218": "EC",
-    "222": "SV",
-    "226": "GQ",
-    "230": "ET",
-    "231": "ET",
-    "232": "ER",
-    "233": "EE",
-    "234": "FO",
-    "238": "FK",
-    "239": "GS",
-    "242": "FJ",
-    "246": "FI",
-    "248": "AX",
-    "249": "FR",
-    "250": "FR",
-    "254": "GF",
-    "258": "PF",
-    "260": "TF",
-    "262": "DJ",
-    "266": "GA",
-    "268": "GE",
-    "270": "GM",
-    "275": "PS",
-    "276": "DE",
-    "278": "DE",
-    "280": "DE",
-    "288": "GH",
-    "292": "GI",
-    "296": "KI",
-    "300": "GR",
-    "304": "GL",
-    "308": "GD",
-    "312": "GP",
-    "316": "GU",
-    "320": "GT",
-    "324": "GN",
-    "328": "GY",
-    "332": "HT",
-    "334": "HM",
-    "336": "VA",
-    "340": "HN",
-    "344": "HK",
-    "348": "HU",
-    "352": "IS",
-    "356": "IN",
-    "360": "ID",
-    "364": "IR",
-    "368": "IQ",
-    "372": "IE",
-    "376": "IL",
-    "380": "IT",
-    "384": "CI",
-    "388": "JM",
-    "392": "JP",
-    "398": "KZ",
-    "400": "JO",
-    "404": "KE",
-    "408": "KP",
-    "410": "KR",
-    "414": "KW",
-    "417": "KG",
-    "418": "LA",
-    "422": "LB",
-    "426": "LS",
-    "428": "LV",
-    "430": "LR",
-    "434": "LY",
-    "438": "LI",
-    "440": "LT",
-    "442": "LU",
-    "446": "MO",
-    "450": "MG",
-    "454": "MW",
-    "458": "MY",
-    "462": "MV",
-    "466": "ML",
-    "470": "MT",
-    "474": "MQ",
-    "478": "MR",
-    "480": "MU",
-    "484": "MX",
-    "492": "MC",
-    "496": "MN",
-    "498": "MD",
-    "499": "ME",
-    "500": "MS",
-    "504": "MA",
-    "508": "MZ",
-    "512": "OM",
-    "516": "NA",
-    "520": "NR",
-    "524": "NP",
-    "528": "NL",
-    "531": "CW",
-    "533": "AW",
-    "534": "SX",
-    "535": "BQ",
-    "540": "NC",
-    "548": "VU",
-    "554": "NZ",
-    "558": "NI",
-    "562": "NE",
-    "566": "NG",
-    "570": "NU",
-    "574": "NF",
-    "578": "NO",
-    "580": "MP",
-    "581": "UM",
-    "583": "FM",
-    "584": "MH",
-    "585": "PW",
-    "586": "PK",
-    "591": "PA",
-    "598": "PG",
-    "600": "PY",
-    "604": "PE",
-    "608": "PH",
-    "612": "PN",
-    "616": "PL",
-    "620": "PT",
-    "624": "GW",
-    "626": "TL",
-    "630": "PR",
-    "634": "QA",
-    "638": "RE",
-    "642": "RO",
-    "643": "RU",
-    "646": "RW",
-    "652": "BL",
-    "654": "SH",
-    "659": "KN",
-    "660": "AI",
-    "662": "LC",
-    "663": "MF",
-    "666": "PM",
-    "670": "VC",
-    "674": "SM",
-    "678": "ST",
-    "682": "SA",
-    "686": "SN",
-    "688": "RS",
-    "690": "SC",
-    "694": "SL",
-    "702": "SG",
-    "703": "SK",
-    "704": "VN",
-    "705": "SI",
-    "706": "SO",
-    "710": "ZA",
-    "716": "ZW",
-    "720": "YE",
-    "724": "ES",
-    "728": "SS",
-    "729": "SD",
-    "732": "EH",
-    "736": "SD",
-    "740": "SR",
-    "744": "SJ",
-    "748": "SZ",
-    "752": "SE",
-    "756": "CH",
-    "760": "SY",
-    "762": "TJ",
-    "764": "TH",
-    "768": "TG",
-    "772": "TK",
-    "776": "TO",
-    "780": "TT",
-    "784": "AE",
-    "788": "TN",
-    "792": "TR",
-    "795": "TM",
-    "796": "TC",
-    "798": "TV",
-    "800": "UG",
-    "804": "UA",
-    "807": "MK",
-    "818": "EG",
-    "826": "GB",
-    "830": "JE",
-    "831": "GG",
-    "832": "JE",
-    "833": "IM",
-    "834": "TZ",
-    "840": "US",
-    "850": "VI",
-    "854": "BF",
-    "858": "UY",
-    "860": "UZ",
-    "862": "VE",
-    "876": "WF",
-    "882": "WS",
-    "886": "YE",
-    "887": "YE",
-    "891": "RS",
-    "894": "ZM",
-    "958": "AA",
-    "959": "QM",
-    "960": "QN",
-    "962": "QP",
-    "963": "QQ",
-    "964": "QR",
-    "965": "QS",
-    "966": "QT",
-    "967": "EU",
-    "968": "QV",
-    "969": "QW",
-    "970": "QX",
-    "971": "QY",
-    "972": "QZ",
-    "973": "XA",
-    "974": "XB",
-    "975": "XC",
-    "976": "XD",
-    "977": "XE",
-    "978": "XF",
-    "979": "XG",
-    "980": "XH",
-    "981": "XI",
-    "982": "XJ",
-    "983": "XK",
-    "984": "XL",
-    "985": "XM",
-    "986": "XN",
-    "987": "XO",
-    "988": "XP",
-    "989": "XQ",
-    "990": "XR",
-    "991": "XS",
-    "992": "XT",
-    "993": "XU",
-    "994": "XV",
-    "995": "XW",
-    "996": "XX",
-    "997": "XY",
-    "998": "XZ",
-    "999": "ZZ",
-    "BU": "MM",
-    "CS": "RS",
-    "CT": "KI",
-    "DD": "DE",
-    "DY": "BJ",
-    "FQ": "AQ",
-    "FX": "FR",
-    "HV": "BF",
-    "JT": "UM",
-    "MI": "UM",
-    "NH": "VU",
-    "NQ": "AQ",
-    "PU": "UM",
-    "PZ": "PA",
-    "QU": "EU",
-    "RH": "ZW",
-    "TP": "TL",
-    "UK": "GB",
-    "VD": "VN",
-    "WK": "UM",
-    "YD": "YE",
-    "YU": "RS",
-    "ZR": "CD",
-};
-
-// Region subtags with complex mappings.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-var complexRegionMappings = {
-    "172": true,
-    "200": true,
-    "530": true,
-    "532": true,
-    "536": true,
-    "582": true,
-    "810": true,
-    "890": true,
-    "AN": true,
-    "NT": true,
-    "PC": true,
-    "SU": true,
-};
-
-// Canonicalize Unicode BCP 47 locale identifiers.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-/* eslint-disable complexity */
-function updateLocaleIdMappings(tag) {
-    assert(IsObject(tag), "tag is an object");
-
-    // Replace deprecated language tags with their preferred values.
-    var language = tag.language;
-    if (hasOwn(language, languageMappings)) {
-        tag.language = languageMappings[language];
-    } else if (hasOwn(language, complexLanguageMappings)) {
-        switch (language) {
-          case "cnr":
-            tag.language = "sr";
-            if (tag.region === undefined)
-                tag.region = "ME";
-            break;
-          case "drw":
-          case "prs":
-          case "tnf":
-            tag.language = "fa";
-            if (tag.region === undefined)
-                tag.region = "AF";
-            break;
-          case "hbs":
-          case "sh":
-            tag.language = "sr";
-            if (tag.script === undefined)
-                tag.script = "Latn";
-            break;
-          case "swc":
-            tag.language = "sw";
-            if (tag.region === undefined)
-                tag.region = "CD";
-            break;
-          default:
-            assert(false, "language not handled: " + language);
-        }
-    }
-
-    // No script replacements are currently present.
-
-    // Replace deprecated subtags with their preferred values.
-    var region = tag.region;
-    if (region !== undefined) {
-        if (hasOwn(region, regionMappings)) {
-            tag.region = regionMappings[region];
-        } else if (hasOwn(region, complexRegionMappings)) {
-            switch (region) {
-              case "172":
-                if (tag.language === "ab") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "az") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "be") {
-                    tag.region = "BY";
-                    break;
-                }
-                if (tag.language === "crh") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "gag") {
-                    tag.region = "MD";
-                    break;
-                }
-                if (tag.language === "got") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "hy") {
-                    tag.region = "AM";
-                    break;
-                }
-                if (tag.language === "ji") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "ka") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "kaa") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "kk") {
-                    tag.region = "KZ";
-                    break;
-                }
-                if (tag.language === "ky") {
-                    tag.region = "KG";
-                    break;
-                }
-                if (tag.language === "os") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "rue") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "sog") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "tg") {
-                    tag.region = "TJ";
-                    break;
-                }
-                if (tag.language === "tk") {
-                    tag.region = "TM";
-                    break;
-                }
-                if (tag.language === "tkr") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "tly") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "ttt") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "ug" && tag.script === "Cyrl") {
-                    tag.region = "KZ";
-                    break;
-                }
-                if (tag.language === "uk") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Armn") {
-                    tag.region = "AM";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Sogd") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Geor") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Goth") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Sogo") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "uz") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "xmf") {
-                    tag.region = "GE";
-                    break;
-                }
-                tag.region = "RU";
-                break;
-              case "200":
-                if (tag.language === "sk") {
-                    tag.region = "SK";
-                    break;
-                }
-                tag.region = "CZ";
-                break;
-              case "530":
-              case "532":
-              case "AN":
-                if (tag.language === "vic") {
-                    tag.region = "SX";
-                    break;
-                }
-                tag.region = "CW";
-                break;
-              case "536":
-              case "NT":
-                if (tag.language === "akk") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "ckb") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "ku" && tag.script === "Arab") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "mis") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "syr") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Xsux") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Hatr") {
-                    tag.region = "IQ";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Syrc") {
-                    tag.region = "IQ";
-                    break;
-                }
-                tag.region = "SA";
-                break;
-              case "582":
-              case "PC":
-                if (tag.language === "mh") {
-                    tag.region = "MH";
-                    break;
-                }
-                if (tag.language === "pau") {
-                    tag.region = "PW";
-                    break;
-                }
-                tag.region = "FM";
-                break;
-              case "810":
-              case "SU":
-                if (tag.language === "ab") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "az") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "be") {
-                    tag.region = "BY";
-                    break;
-                }
-                if (tag.language === "crh") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "et") {
-                    tag.region = "EE";
-                    break;
-                }
-                if (tag.language === "gag") {
-                    tag.region = "MD";
-                    break;
-                }
-                if (tag.language === "got") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "hy") {
-                    tag.region = "AM";
-                    break;
-                }
-                if (tag.language === "ji") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "ka") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "kaa") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "kk") {
-                    tag.region = "KZ";
-                    break;
-                }
-                if (tag.language === "ky") {
-                    tag.region = "KG";
-                    break;
-                }
-                if (tag.language === "lt") {
-                    tag.region = "LT";
-                    break;
-                }
-                if (tag.language === "ltg") {
-                    tag.region = "LV";
-                    break;
-                }
-                if (tag.language === "lv") {
-                    tag.region = "LV";
-                    break;
-                }
-                if (tag.language === "os") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "rue") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "sgs") {
-                    tag.region = "LT";
-                    break;
-                }
-                if (tag.language === "sog") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "tg") {
-                    tag.region = "TJ";
-                    break;
-                }
-                if (tag.language === "tk") {
-                    tag.region = "TM";
-                    break;
-                }
-                if (tag.language === "tkr") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "tly") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "ttt") {
-                    tag.region = "AZ";
-                    break;
-                }
-                if (tag.language === "ug" && tag.script === "Cyrl") {
-                    tag.region = "KZ";
-                    break;
-                }
-                if (tag.language === "uk") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Armn") {
-                    tag.region = "AM";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Sogd") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Geor") {
-                    tag.region = "GE";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Goth") {
-                    tag.region = "UA";
-                    break;
-                }
-                if (tag.language === "und" && tag.script === "Sogo") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "uz") {
-                    tag.region = "UZ";
-                    break;
-                }
-                if (tag.language === "vro") {
-                    tag.region = "EE";
-                    break;
-                }
-                if (tag.language === "xmf") {
-                    tag.region = "GE";
-                    break;
-                }
-                tag.region = "RU";
-                break;
-              case "890":
-                if (tag.language === "bs") {
-                    tag.region = "BA";
-                    break;
-                }
-                if (tag.language === "hr") {
-                    tag.region = "HR";
-                    break;
-                }
-                if (tag.language === "mk") {
-                    tag.region = "MK";
-                    break;
-                }
-                if (tag.language === "sl") {
-                    tag.region = "SI";
-                    break;
-                }
-                tag.region = "RS";
-                break;
-              default:
-                assert(false, "region not handled: " + region);
-            }
-        }
-
-        // No variant replacements are currently present.
-        // No extension replacements are currently present.
-        // Private use sequences are left as is.
-
-    }
-}
-/* eslint-enable complexity */
-
-// Canonicalize grandfathered locale identifiers.
-// Derived from CLDR Supplemental Data, version 35.1.
-// https://github.com/unicode-org/cldr.git
-function updateGrandfatheredMappings(tag) {
-    assert(IsObject(tag), "tag is an object");
-
-    // We're mapping regular grandfathered tags to non-grandfathered form here.
-    // Other tags remain unchanged.
-    //
-    // regular       = "art-lojban"
-    //               / "cel-gaulish"
-    //               / "no-bok"
-    //               / "no-nyn"
-    //               / "zh-guoyu"
-    //               / "zh-hakka"
-    //               / "zh-min"
-    //               / "zh-min-nan"
-    //               / "zh-xiang"
-    //
-    // Therefore we can quickly exclude most tags by checking every
-    // |unicode_locale_id| subcomponent for characteristics not shared by any of
-    // the regular grandfathered (RG) tags:
-    //
-    //   * Real-world |unicode_language_subtag|s are all two or three letters,
-    //     so don't waste time running a useless |language.length > 3| fast-path.
-    //   * No RG tag has a "script"-looking component.
-    //   * No RG tag has a "region"-looking component.
-    //   * The RG tags that match |unicode_locale_id| (art-lojban, cel-gaulish,
-    //     zh-guoyu, zh-hakka, zh-xiang) have exactly one "variant". (no-bok,
-    //     no-nyn, zh-min, and zh-min-nan require BCP47's extlang subtag
-    //     that |unicode_locale_id| doesn't support.)
-    //   * No RG tag contains |extensions| or |pu_extensions|.
-    if (tag.script !== undefined ||
-        tag.region !== undefined ||
-        tag.variants.length !== 1 ||
-        tag.extensions.length !== 0 ||
-        tag.privateuse !== undefined)
-    {
-        return;
-    }
-
-    // art-lojban -> jbo
-    if (tag.language === "art" && tag.variants[0] === "lojban") {
-        tag.language = "jbo";
-        tag.variants.length = 0;
-    }
-
-    // cel-gaulish -> xtg-x-cel-gaulish
-    else if (tag.language === "cel" && tag.variants[0] === "gaulish") {
-        tag.language = "xtg";
-        tag.variants.length = 0;
-        tag.privateuse = "x-cel-gaulish";
-    }
-
-    // zh-guoyu -> zh
-    else if (tag.language === "zh" && tag.variants[0] === "guoyu") {
-        tag.language = "zh";
-        tag.variants.length = 0;
-    }
-
-    // zh-hakka -> hak
-    else if (tag.language === "zh" && tag.variants[0] === "hakka") {
-        tag.language = "hak";
-        tag.variants.length = 0;
-    }
-
-    // zh-xiang -> hsn
-    else if (tag.language === "zh" && tag.variants[0] === "xiang") {
-        tag.language = "hsn";
-        tag.variants.length = 0;
-    }
-}

deleted file mode 100644
--- a/js/src/builtin/intl/UnicodeExtensionsGenerated.js
+++ /dev/null
@@ -1,371 +0,0 @@
-// Generated by make_intl_data.py. DO NOT EDIT.
-// Version: CLDR-35.1
-// URL: https://unicode.org/Public/cldr/35.1/core.zip
-
-/**
- * Mapping from deprecated BCP 47 Unicode extension types to their preferred
- * values.
- *
- * Spec: https://www.unicode.org/reports/tr35/#Unicode_Locale_Extension_Data_Files
- */
-var deprecatedUnicodeExtensionTypes = {
-    ca: {
-        // Ethiopic calendar, Amete Alem (epoch approx. 5493 B.C.E)
-        "ethiopic-amete-alem": "ethioaa",
-
-        // Civil (algorithmic) Arabic calendar
-        "islamicc": "islamic-civil",
-    },
-    kb: {
-        // The second level to be backwards
-        "yes": "true",
-    },
-    kc: {
-        // The case level is inserted in front of tertiary
-        "yes": "true",
-    },
-    kh: {
-        // Hiragana to be sorted before all non-variable on quaternary level
-        "yes": "true",
-    },
-    kk: {
-        // Convert text into Normalization Form D before calculating collation weights
-        "yes": "true",
-    },
-    kn: {
-        // A sequence of decimal digits is sorted at primary level with its numeric value
-        "yes": "true",
-    },
-    ks: {
-        // The primary level
-        "primary": "level1",
-
-        // The tertiary level
-        "tertiary": "level3",
-    },
-    ms: {
-        // UK System of measurement: feet, pints, etc.; pints are 20oz
-        "imperial": "uksystem",
-    },
-    rg: {
-        "cn11": "cnbj",
-        "cn12": "cntj",
-        "cn13": "cnhe",
-        "cn14": "cnsx",
-        "cn15": "cnmn",
-        "cn21": "cnln",
-        "cn22": "cnjl",
-        "cn23": "cnhl",
-        "cn31": "cnsh",
-        "cn32": "cnjs",
-        "cn33": "cnzj",
-        "cn34": "cnah",
-        "cn35": "cnfj",
-        "cn36": "cnjx",
-        "cn37": "cnsd",
-        "cn41": "cnha",
-        "cn42": "cnhb",
-        "cn43": "cnhn",
-        "cn44": "cngd",
-        "cn45": "cngx",
-        "cn46": "cnhi",
-        "cn50": "cncq",
-        "cn51": "cnsc",
-        "cn52": "cngz",
-        "cn53": "cnyn",
-        "cn54": "cnxz",
-        "cn61": "cnsn",
-        "cn62": "cngs",
-        "cn63": "cnqh",
-        "cn64": "cnnx",
-        "cn65": "cnxj",
-        "cz10a": "cz110",
-        "cz10b": "cz111",
-        "cz10c": "cz112",
-        "cz10d": "cz113",
-        "cz10e": "cz114",
-        "cz10f": "cz115",
-        "cz611": "cz663",
-        "cz612": "cz632",
-        "cz613": "cz633",
-        "cz614": "cz634",
-        "cz615": "cz635",
-        "cz621": "cz641",
-        "cz622": "cz642",
-        "cz623": "cz643",
-        "cz624": "cz644",
-        "cz626": "cz646",
-        "cz627": "cz647",
-        "czjc": "cz31",
-        "czjm": "cz64",
-        "czka": "cz41",
-        "czkr": "cz52",
-        "czli": "cz51",
-        "czmo": "cz80",
-        "czol": "cz71",
-        "czpa": "cz53",
-        "czpl": "cz32",
-        "czpr": "cz10",
-        "czst": "cz20",
-        "czus": "cz42",
-        "czvy": "cz63",
-        "czzl": "cz72",
-        "fra": "frges",
-        "frb": "frnaq",
-        "frc": "frara",
-        "frd": "frbfc",
-        "fre": "frbre",
-        "frf": "frcvl",
-        "frg": "frges",
-        "frh": "frcor",
-        "fri": "frbfc",
-        "frj": "fridf",
-        "frk": "frocc",
-        "frl": "frnaq",
-        "frm": "frges",
-        "frn": "frocc",
-        "fro": "frhdf",
-        "frp": "frnor",
-        "frq": "frnor",
-        "frr": "frpdl",
-        "frs": "frhdf",
-        "frt": "frnaq",
-        "fru": "frpac",
-        "frv": "frara",
-        "laxn": "laxs",
-        "lud": "lucl",
-        "lug": "luec",
-        "lul": "luca",
-        "mrnkc": "mr13",
-        "nzn": "nzauk",
-        "nzs": "nzcan",
-        "omba": "ombj",
-        "omsh": "omsj",
-        "plds": "pl02",
-        "plkp": "pl04",
-        "pllb": "pl08",
-        "plld": "pl10",
-        "pllu": "pl06",
-        "plma": "pl12",
-        "plmz": "pl14",
-        "plop": "pl16",
-        "plpd": "pl20",
-        "plpk": "pl18",
-        "plpm": "pl22",
-        "plsk": "pl26",
-        "plsl": "pl24",
-        "plwn": "pl28",
-        "plwp": "pl30",
-        "plzp": "pl32",
-        "tteto": "tttob",
-        "ttrcm": "ttmrc",
-        "ttwto": "tttob",
-        "twkhq": "twkhh",
-        "twtnq": "twtnn",
-        "twtpq": "twnwt",
-        "twtxq": "twtxg",
-    },
-    sd: {
-        "cn11": "cnbj",
-        "cn12": "cntj",
-        "cn13": "cnhe",
-        "cn14": "cnsx",
-        "cn15": "cnmn",
-        "cn21": "cnln",
-        "cn22": "cnjl",
-        "cn23": "cnhl",
-        "cn31": "cnsh",
-        "cn32": "cnjs",
-        "cn33": "cnzj",
-        "cn34": "cnah",
-        "cn35": "cnfj",
-        "cn36": "cnjx",
-        "cn37": "cnsd",
-        "cn41": "cnha",
-        "cn42": "cnhb",
-        "cn43": "cnhn",
-        "cn44": "cngd",
-        "cn45": "cngx",
-        "cn46": "cnhi",
-        "cn50": "cncq",
-        "cn51": "cnsc",
-        "cn52": "cngz",
-        "cn53": "cnyn",
-        "cn54": "cnxz",
-        "cn61": "cnsn",
-        "cn62": "cngs",
-        "cn63": "cnqh",
-        "cn64": "cnnx",
-        "cn65": "cnxj",
-        "cz10a": "cz110",
-        "cz10b": "cz111",
-        "cz10c": "cz112",
-        "cz10d": "cz113",
-        "cz10e": "cz114",
-        "cz10f": "cz115",
-        "cz611": "cz663",
-        "cz612": "cz632",
-        "cz613": "cz633",
-        "cz614": "cz634",
-        "cz615": "cz635",
-        "cz621": "cz641",
-        "cz622": "cz642",
-        "cz623": "cz643",
-        "cz624": "cz644",
-        "cz626": "cz646",
-        "cz627": "cz647",
-        "czjc": "cz31",
-        "czjm": "cz64",
-        "czka": "cz41",
-        "czkr": "cz52",
-        "czli": "cz51",
-        "czmo": "cz80",
-        "czol": "cz71",
-        "czpa": "cz53",
-        "czpl": "cz32",
-        "czpr": "cz10",
-        "czst": "cz20",
-        "czus": "cz42",
-        "czvy": "cz63",
-        "czzl": "cz72",
-        "fra": "frges",
-        "frb": "frnaq",
-        "frc": "frara",
-        "frd": "frbfc",
-        "fre": "frbre",
-        "frf": "frcvl",
-        "frg": "frges",
-        "frh": "frcor",
-        "fri": "frbfc",
-        "frj": "fridf",
-        "frk": "frocc",
-        "frl": "frnaq",
-        "frm": "frges",
-        "frn": "frocc",
-        "fro": "frhdf",
-        "frp": "frnor",
-        "frq": "frnor",
-        "frr": "frpdl",
-        "frs": "frhdf",
-        "frt": "frnaq",
-        "fru": "frpac",
-        "frv": "frara",
-        "laxn": "laxs",
-        "lud": "lucl",
-        "lug": "luec",
-        "lul": "luca",
-        "mrnkc": "mr13",
-        "nzn": "nzauk",
-        "nzs": "nzcan",
-        "omba": "ombj",
-        "omsh": "omsj",
-        "plds": "pl02",
-        "plkp": "pl04",
-        "pllb": "pl08",
-        "plld": "pl10",
-        "pllu": "pl06",
-        "plma": "pl12",
-        "plmz": "pl14",
-        "plop": "pl16",
-        "plpd": "pl20",
-        "plpk": "pl18",
-        "plpm": "pl22",
-        "plsk": "pl26",
-        "plsl": "pl24",
-        "plwn": "pl28",
-        "plwp": "pl30",
-        "plzp": "pl32",
-        "tteto": "tttob",
-        "ttrcm": "ttmrc",
-        "ttwto": "tttob",
-        "twkhq": "twkhh",
-        "twtnq": "twtnn",
-        "twtpq": "twnwt",
-        "twtxq": "twtxg",
-    },
-    tz: {
-        // Amundsen-Scott Station, South Pole
-        "aqams": "nzakl",
-
-        // Chongqing, China
-        "cnckg": "cnsha",
-
-        // Harbin, China
-        "cnhrb": "cnsha",
-
-        // Kashgar, China
-        "cnkhg": "cnurc",
-
-        // Havana, Cuba
-        "cuba": "cuhav",
-
-        // Cairo, Egypt
-        "egypt": "egcai",
-
-        // Dublin, Ireland
-        "eire": "iedub",
-
-        // 5 hours behind UTC
-        "est": "utcw05",
-
-        // Greenwich Mean Time
-        "gmt0": "gmt",
-
-        // Hong Kong SAR China
-        "hongkong": "hkhkg",
-
-        // 10 hours behind UTC
-        "hst": "utcw10",
-
-        // Reykjavik, Iceland
-        "iceland": "isrey",
-
-        // Tehran, Iran
-        "iran": "irthr",
-
-        // Jerusalem
-        "israel": "jeruslm",
-
-        // Jamaica
-        "jamaica": "jmkin",
-
-        // Tokyo, Japan
-        "japan": "jptyo",
-
-        // Tripoli, Libya
-        "libya": "lytip",
-
-        // 7 hours behind UTC
-        "mst": "utcw07",
-
-        // Denver, United States
-        "navajo": "usden",
-
-        // Warsaw, Poland
-        "poland": "plwaw",
-
-        // Lisbon, Portugal
-        "portugal": "ptlis",
-
-        // Shanghai, China
-        "prc": "cnsha",
-
-        // Taipei, Taiwan
-        "roc": "twtpe",
-
-        // Seoul, South Korea
-        "rok": "krsel",
-
-        // Istanbul, Turkey
-        "turkey": "trist",
-
-        // UTC (Coordinated Universal Time)
-        "uct": "utc",
-
-        // Shiprock (Navajo), United States
-        "usnavajo": "usden",
-
-        // UTC (Coordinated Universal Time)
-        "zulu": "utc",
-    },
-};

--- a/js/src/builtin/intl/make_intl_data.py
+++ b/js/src/builtin/intl/make_intl_data.py
@@ -9,19 +9,19 @@
     make_intl_data.py langtags [ldmlSupplemental.dtd supplementalMetadata.xml likelySubtags.xml]
     make_intl_data.py tzdata
     make_intl_data.py currency
     make_intl_data.py unicode-ext
 
 
     Target "langtags":
     This script extracts information about mappings between deprecated and
-    current Unicode BCP 47 locale identifiers from CLDR and converts it to
-    JavaScript object definitions in LangTagMappingsGenerated.js. The
-    definitions are used in Intl.js.
+    current Unicode BCP 47 locale identifiers from CLDR and converts it to C++
+    mapping code in LanguageTagGenerated.cpp. The code is used in
+    LanguageTag.cpp.
 
 
     Target "tzdata":
     This script computes which time zone informations are not up-to-date in ICU
     and provides the necessary mappings to workaround this problem.
     https://ssl.icu-project.org/trac/ticket/12044
 
 
@@ -100,303 +100,16 @@ def writeMappingsVar(println, mapping, n
             if key != preferred:
                 raise Exception(
                     "Expected '{0}' matches preferred locale '{1}'".format(key, preferred))
             value = '"{0}"'.format(prefix)
         println(u'    "{0}": {1},'.format(key, value))
     println(u"};")
 
 
-def writeUpdateLocaleIdMappingsFunction(println,
-                                        complex_language_mappings,
-                                        complex_region_mappings,
-                                        description, source, url):
-    """ Writes a function definition that performs language tag mapping. """
-    println(u"")
-    writeMappingHeader(println, description, source, url)
-    println(u"""\
-/* eslint-disable complexity */
-function updateLocaleIdMappings(tag) {
-    assert(IsObject(tag), "tag is an object");
-
-    // Replace deprecated language tags with their preferred values.
-    var language = tag.language;
-    if (hasOwn(language, languageMappings)) {
-        tag.language = languageMappings[language];
-    } else if (hasOwn(language, complexLanguageMappings)) {
-        switch (language) {""")
-
-    # Merge duplicate language entries.
-    language_aliases = {}
-    for (deprecated_language, (language, script, region)) in (
-        sorted(complex_language_mappings.items(), key=itemgetter(0))
-    ):
-        key = (language, script, region)
-        if key not in language_aliases:
-            language_aliases[key] = []
-        else:
-            language_aliases[key].append(deprecated_language)
-
-    for (deprecated_language, (language, script, region)) in (
-        sorted(complex_language_mappings.items(), key=itemgetter(0))
-    ):
-        key = (language, script, region)
-        if deprecated_language in language_aliases[key]:
-            continue
-
-        for lang in [deprecated_language] + language_aliases[key]:
-            println(u"""
-          case "{}":
-            """.format(lang).rstrip().strip("\n"))
-
-        println(u"""
-            tag.language = "{}";
-        """.format(language).rstrip().strip("\n"))
-        if script is not None:
-            println(u"""
-            if (tag.script === undefined)
-                tag.script = "{}";
-            """.format(script).rstrip().strip("\n"))
-        if region is not None:
-            println(u"""
-            if (tag.region === undefined)
-                tag.region = "{}";
-            """.format(region).rstrip().strip("\n"))
-        println(u"""
-            break;
-        """.rstrip().strip("\n"))
-
-    println(u"""
-          default:
-            assert(false, "language not handled: " + language);
-        }
-    }
-
-    // No script replacements are currently present.
-
-    // Replace deprecated subtags with their preferred values.
-    var region = tag.region;
-    if (region !== undefined) {
-        if (hasOwn(region, regionMappings)) {
-            tag.region = regionMappings[region];
-        } else if (hasOwn(region, complexRegionMappings)) {
-            switch (region) {""".lstrip("\n"))
-
-    # |non_default_replacements| is a list and hence not hashable. Convert it
-    # to a string to get a proper hashable value.
-    def hash_key(default, non_default_replacements):
-        return (default, str(sorted(str(v) for v in non_default_replacements)))
-
-    # Merge duplicate region entries.
-    region_aliases = {}
-    for (deprecated_region, (default, non_default_replacements)) in (
-        sorted(complex_region_mappings.items(), key=itemgetter(0))
-    ):
-        key = hash_key(default, non_default_replacements)
-        if key not in region_aliases:
-            region_aliases[key] = []
-        else:
-            region_aliases[key].append(deprecated_region)
-
-    for (deprecated_region, (default, non_default_replacements)) in (
-        sorted(complex_region_mappings.items(), key=itemgetter(0))
-    ):
-        key = hash_key(default, non_default_replacements)
-        if deprecated_region in region_aliases[key]:
-            continue
-
-        for region in [deprecated_region] + region_aliases[key]:
-            println(u"""
-              case "{}":
-            """.format(region).rstrip().strip("\n"))
-
-        for (language, script, region) in sorted(non_default_replacements, key=itemgetter(0)):
-            if script is None:
-                println(u"""
-                if (tag.language === "{}") {{
-                """.format(language).rstrip().strip("\n"))
-            else:
-                println(u"""
-                if (tag.language === "{}" && tag.script === "{}") {{
-                """.format(language, script).rstrip().strip("\n"))
-            println(u"""
-                    tag.region = "{}";
-                    break;
-                }}
-            """.format(region).rstrip().strip("\n"))
-
-        println(u"""
-                tag.region = "{}";
-                break;
-        """.format(default).rstrip().strip("\n"))
-
-    println(u"""
-              default:
-                assert(false, "region not handled: " + region);
-            }
-        }
-
-        // No variant replacements are currently present.
-        // No extension replacements are currently present.
-        // Private use sequences are left as is.
-
-    }
-}
-/* eslint-enable complexity */
-""".strip("\n"))
-
-
-def writeGrandfatheredMappingsFunction(println,
-                                       grandfathered_mappings,
-                                       description, source, url):
-    """ Writes a function definition that maps grandfathered language tags. """
-    println(u"")
-    writeMappingHeader(println, description, source, url)
-    println(u"""\
-function updateGrandfatheredMappings(tag) {
-    assert(IsObject(tag), "tag is an object");
-
-    // We're mapping regular grandfathered tags to non-grandfathered form here.
-    // Other tags remain unchanged.
-    //
-    // regular       = "art-lojban"
-    //               / "cel-gaulish"
-    //               / "no-bok"
-    //               / "no-nyn"
-    //               / "zh-guoyu"
-    //               / "zh-hakka"
-    //               / "zh-min"
-    //               / "zh-min-nan"
-    //               / "zh-xiang"
-    //
-    // Therefore we can quickly exclude most tags by checking every
-    // |unicode_locale_id| subcomponent for characteristics not shared by any of
-    // the regular grandfathered (RG) tags:
-    //
-    //   * Real-world |unicode_language_subtag|s are all two or three letters,
-    //     so don't waste time running a useless |language.length > 3| fast-path.
-    //   * No RG tag has a "script"-looking component.
-    //   * No RG tag has a "region"-looking component.
-    //   * The RG tags that match |unicode_locale_id| (art-lojban, cel-gaulish,
-    //     zh-guoyu, zh-hakka, zh-xiang) have exactly one "variant". (no-bok,
-    //     no-nyn, zh-min, and zh-min-nan require BCP47's extlang subtag
-    //     that |unicode_locale_id| doesn't support.)
-    //   * No RG tag contains |extensions| or |pu_extensions|.
-    if (tag.script !== undefined ||
-        tag.region !== undefined ||
-        tag.variants.length !== 1 ||
-        tag.extensions.length !== 0 ||
-        tag.privateuse !== undefined)
-    {
-        return;
-    }""")
-
-    # From Unicode BCP 47 locale identifier <https://unicode.org/reports/tr35/>.
-    #
-    # Doesn't allow any 'extensions' subtags.
-    re_unicode_locale_id = re.compile(
-        r"""
-        ^
-        # unicode_language_id = unicode_language_subtag
-        #     unicode_language_subtag = alpha{2,3} | alpha{5,8}
-        (?P<language>[a-z]{2,3}|[a-z]{5,8})
-
-        # (sep unicode_script_subtag)?
-        #     unicode_script_subtag = alpha{4}
-        (?:-(?P<script>[a-z]{4}))?
-
-        # (sep unicode_region_subtag)?
-        #     unicode_region_subtag = (alpha{2} | digit{3})
-        (?:-(?P<region>([a-z]{2}|[0-9]{3})))?
-
-        # (sep unicode_variant_subtag)*
-        #     unicode_variant_subtag = (alphanum{5,8} | digit alphanum{3})
-        (?P<variants>(-([a-z0-9]{5,8}|[0-9][a-z0-9]{3}))+)?
-
-        # pu_extensions?
-        #     pu_extensions = sep [xX] (sep alphanum{1,8})+
-        (?:-(?P<privateuse>x(-[a-z0-9]{1,8})+))?
-        $
-        """, re.IGNORECASE | re.VERBOSE)
-
-    is_first = True
-
-    for (tag, modern) in sorted(grandfathered_mappings.items(), key=itemgetter(0)):
-        tag_match = re_unicode_locale_id.match(tag)
-        assert tag_match is not None
-
-        tag_language = tag_match.group("language")
-        assert tag_match.group("script") is None, (
-               "{} does not contain a script subtag".format(tag))
-        assert tag_match.group("region") is None, (
-               "{} does not contain a region subtag".format(tag))
-        tag_variants = tag_match.group("variants")
-        assert tag_variants is not None, (
-               "{} contains a variant subtag".format(tag))
-        assert tag_match.group("privateuse") is None, (
-               "{} does not contain a privateuse subtag".format(tag))
-
-        tag_variant = tag_variants[1:]
-        assert "-" not in tag_variant, (
-               "{} contains only a single variant".format(tag))
-
-        modern_match = re_unicode_locale_id.match(modern)
-        assert modern_match is not None
-
-        modern_language = modern_match.group("language")
-        modern_script = modern_match.group("script")
-        modern_region = modern_match.group("region")
-        modern_variants = modern_match.group("variants")
-        modern_privateuse = modern_match.group("privateuse")
-
-        println(u"""
-    // {} -> {}
-""".format(tag, modern).rstrip())
-
-        println(u"""
-    {}if (tag.language === "{}" && tag.variants[0] === "{}") {{
-        """.format("" if is_first else "else ", tag_language, tag_variant).rstrip().strip("\n"))
-
-        is_first = False
-
-        println(u"""
-        tag.language = "{}";
-        """.format(modern_language).rstrip().strip("\n"))
-
-        if modern_script is not None:
-            println(u"""
-        tag.script = "{}";
-        """.format(modern_script).rstrip().strip("\n"))
-
-        if modern_region is not None:
-            println(u"""
-        tag.region = "{}";
-        """.format(modern_region).rstrip().strip("\n"))
-
-        if modern_variants is not None:
-            println(u"""
-        tag.variants = {};
-        """.format(sorted(modern_variants[1:].split("-"))).rstrip().strip("\n"))
-        else:
-            println(u"""
-        tag.variants.length = 0;
-        """.rstrip().strip("\n"))
-
-        if modern_privateuse is not None:
-            println(u"""
-        tag.privateuse = "{}";
-        """.format(modern_privateuse).rstrip().strip("\n"))
-
-        println(u"""
-    }""".rstrip().strip("\n"))
-
-    println(u"""
-}""".lstrip("\n"))
-
-
 def writeMappingsBinarySearch(println, fn_name, type_name, name, validate_fn, mappings,
                               tag_maxlength, description, source, url):
     """ Emit code to perform a binary search on language tag subtags.
 
         Uses the contents of |mapping|, which can either be a dictionary or set,
         to emit a mapping function to find subtag replacements.
     """
     println(u"")
@@ -503,18 +216,18 @@ bool js::intl::LanguageTag::{0}({1} {2})
     if trailing_return:
         println(u"""
   return false;""")
 
     println(u"""
 }""".lstrip("\n"))
 
 
-def writeComplexLanguageTagMappingsNative(println, complex_language_mappings,
-                                          description, source, url):
+def writeComplexLanguageTagMappings(println, complex_language_mappings,
+                                    description, source, url):
     println(u"")
     writeMappingHeader(println, description, source, url)
     println(u"""
 void js::intl::LanguageTag::performComplexLanguageMappings() {
   MOZ_ASSERT(IsStructurallyValidLanguageTag(language().range()));
 """.lstrip())
 
     # Merge duplicate language entries.
@@ -562,18 +275,18 @@ void js::intl::LanguageTag::performCompl
         println(u"""
   }""".strip("\n"))
 
     println(u"""
 }
 """.strip("\n"))
 
 
-def writeComplexRegionTagMappingsNative(println, complex_region_mappings,
-                                        description, source, url):
+def writeComplexRegionTagMappings(println, complex_region_mappings,
+                                  description, source, url):
     println(u"")
     writeMappingHeader(println, description, source, url)
     println(u"""
 void js::intl::LanguageTag::performComplexRegionMappings() {
   MOZ_ASSERT(IsStructurallyValidLanguageTag(language().range()));
   MOZ_ASSERT(IsStructurallyValidRegionTag(region().range()));
 """.lstrip())
 
@@ -646,18 +359,18 @@ void js::intl::LanguageTag::performCompl
     }}
   }}""".format(default).rstrip().strip("\n"))
 
     println(u"""
 }
 """.strip("\n"))
 
 
-def writeGrandfatheredMappingsFunctionNative(println, grandfathered_mappings,
-                                             description, source, url):
+def writeGrandfatheredMappingsFunction(println, grandfathered_mappings,
+                                       description, source, url):
     """ Writes a function definition that maps grandfathered language tags. """
     println(u"")
     writeMappingHeader(println, description, source, url)
     println(u"""\
 bool js::intl::LanguageTag::updateGrandfatheredMappings(JSContext* cx) {
   // We're mapping regular grandfathered tags to non-grandfathered form here.
   // Other tags remain unchanged.
   //
@@ -1062,48 +775,16 @@ def readSupplementalData(supplemental_dt
             "complexRegionMappings": complex_region_mappings_final,
             "likelySubtags": likely_subtags,
             }
 
 
 def writeCLDRLanguageTagData(println, data, url):
     """ Writes the language tag data to the Intl data file. """
 
-    source = u"CLDR Supplemental Data, version {}".format(data["version"])
-    grandfathered_mappings = data["grandfatheredMappings"]
-    language_mappings = data["languageMappings"]
-    complex_language_mappings = data["complexLanguageMappings"]
-    region_mappings = data["regionMappings"]
-    complex_region_mappings = data["complexRegionMappings"]
-
-    writeMappingsVar(println, grandfathered_mappings, "grandfatheredMappings",
-                     "Mappings from grandfathered tags to preferred values.", source, url)
-    writeMappingsVar(println, language_mappings, "languageMappings",
-                     "Mappings from language subtags to preferred values.", source, url)
-    writeMappingsVar(println, {key: True for key in complex_language_mappings},
-                     "complexLanguageMappings",
-                     "Language subtags with complex mappings.", source, url)
-    writeMappingsVar(println, region_mappings, "regionMappings",
-                     "Mappings from region subtags to preferred values.", source, url)
-    writeMappingsVar(println, {key: True for key in complex_region_mappings},
-                     "complexRegionMappings",
-                     "Region subtags with complex mappings.", source, url)
-
-    writeUpdateLocaleIdMappingsFunction(println, complex_language_mappings,
-                                        complex_region_mappings,
-                                        "Canonicalize Unicode BCP 47 locale identifiers.",
-                                        source, url)
-    writeGrandfatheredMappingsFunction(println, grandfathered_mappings,
-                                       "Canonicalize grandfathered locale identifiers.",
-                                       source, url)
-
-
-def writeCLDRLanguageTagDataNative(println, data, url):
-    """ Writes the language tag data to the Intl data file. """
-
     println(generatedFileWarning)
 
     println(u"""
 #include "mozilla/Assertions.h"
 #include "mozilla/Range.h"
 #include "mozilla/TextUtils.h"
 
 #include <algorithm>
@@ -1181,24 +862,24 @@ static inline const char* SearchReplacem
                               region_mappings, region_maxlength,
                               "Mappings from region subtags to preferred values.", source, url)
     writeMappingsBinarySearch(println, "complexRegionMapping",
                               "const RegionSubtag&", "region",
                               "IsStructurallyValidRegionTag",
                               complex_region_mappings.keys(), region_maxlength,
                               "Region subtags with complex mappings.", source, url)
 
-    writeComplexLanguageTagMappingsNative(println, complex_language_mappings,
-                                          "Language subtags with complex mappings.", source, url)
-    writeComplexRegionTagMappingsNative(println, complex_region_mappings,
-                                        "Region subtags with complex mappings.", source, url)
-
-    writeGrandfatheredMappingsFunctionNative(println, grandfathered_mappings,
-                                             "Canonicalize grandfathered locale identifiers.", source,
-                                             url)
+    writeComplexLanguageTagMappings(println, complex_language_mappings,
+                                    "Language subtags with complex mappings.", source, url)
+    writeComplexRegionTagMappings(println, complex_region_mappings,
+                                  "Region subtags with complex mappings.", source, url)
+
+    writeGrandfatheredMappingsFunction(println, grandfathered_mappings,
+                                       "Canonicalize grandfathered locale identifiers.", source,
+                                       url)
 
 
 def writeCLDRLanguageTagLikelySubtagsTest(println, data, url):
     """ Writes the likely-subtags test file. """
 
     source = u"CLDR Supplemental Data, version {}".format(data["version"])
     language_mappings = data["languageMappings"]
     complex_language_mappings = data["complexLanguageMappings"]
@@ -1317,17 +998,17 @@ for (let [tag, minimal] of Object.entrie
 }""")
 
     println(u"""
 if (typeof reportCompare === "function")
     reportCompare(0, 0);""")
 
 
 def updateCLDRLangTags(args):
-    """ Update the LangTagMappingsCLDRGenerated.js file. """
+    """ Update the LanguageTagGenerated.cpp file. """
     url = args.url
     branch = args.branch
     revision = args.revision
     out = args.out
     files = args.files
 
     print("Arguments:")
     print("\tDownload url: %s" % url)
@@ -1399,27 +1080,18 @@ def updateCLDRLangTags(args):
     print("Processing CLDR supplemental data...")
     data = readSupplementalData(supplemental_dtd_file,
                                 supplemental_metadata_file,
                                 likely_subtags_file)
 
     print("Writing Intl data...")
     with io.open(out, mode="w", encoding="utf-8", newline="") as f:
         println = partial(print, file=f)
-
-        println(u"// Generated by make_intl_data.py. DO NOT EDIT.")
         writeCLDRLanguageTagData(println, data, url)
 
-    print("Writing Intl data...")
-    native_out = "LanguageTagGenerated.cpp"
-    # native_out = os.path.splitext(out)[0] + ".cpp"
-    with io.open(native_out, mode="w", encoding="utf-8", newline="") as f:
-        println = partial(print, file=f)
-        writeCLDRLanguageTagDataNative(println, data, url)
-
     print("Writing Intl test data...")
     test_file = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                              "../../tests/non262/Intl/Locale/likely-subtags-generated.js")
     with io.open(test_file, mode="w", encoding="utf-8", newline="") as f:
         println = partial(print, file=f)
 
         println(u"// |reftest| skip-if(!this.hasOwnProperty('Intl')||"
                 u"(!this.Intl.Locale&&!this.hasOwnProperty('addIntlExtras')))")
@@ -2691,17 +2363,17 @@ if __name__ == "__main__":
                                   metavar="URL",
                                   default="https://github.com/unicode-org/cldr.git",
                                   help="URL to git repository (default: %(default)s)")
     parser_cldr_tags.add_argument("--branch", default="latest",
                                   help="Git branch (default: %(default)s)")
     parser_cldr_tags.add_argument("--revision", default="HEAD",
                                   help="Git revision (default: %(default)s)")
     parser_cldr_tags.add_argument("--out",
-                                  default="LangTagMappingsGenerated.js",
+                                  default="LanguageTagGenerated.cpp",
                                   help="Output file (default: %(default)s)")
     parser_cldr_tags.add_argument("files",
                                   nargs="*",
                                   help="Local ldmlSupplemental.dtd, supplementalMetadata.xml, "
                                        "and likelySubtags.xml files, if omitted uses <URL>")
     parser_cldr_tags.set_defaults(func=updateCLDRLangTags)
 
     parser_tz = subparsers.add_parser("tzdata", help="Update tzdata")

--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -476,21 +476,19 @@ selfhosted_inputs = [
     'builtin/WeakMap.js',
     'builtin/WeakSet.js'
 ] + ([
     'builtin/intl/Collator.js',
     'builtin/intl/CommonFunctions.js',
     'builtin/intl/CurrencyDataGenerated.js',
     'builtin/intl/DateTimeFormat.js',
     'builtin/intl/IntlObject.js',
-    'builtin/intl/LangTagMappingsGenerated.js',
     'builtin/intl/NumberFormat.js',
     'builtin/intl/PluralRules.js',
     'builtin/intl/RelativeTimeFormat.js',
-    'builtin/intl/UnicodeExtensionsGenerated.js',
 ] if CONFIG['ENABLE_INTL_API'] else [])
 
 # Prepare self-hosted JS code for embedding
 GeneratedFile('selfhosted.out.h', 'selfhosted.js',
               script='builtin/embedjs.py',
               entry_point='generate_selfhosted',
               inputs=selfhosted_inputs)