Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

10 files changed, 1791 insertions, 0 deletions

diff --git a/js/public/friend/DOMProxy.h b/js/public/friend/DOMProxy.h
new file mode 100644
index 0000000000..533c327adb
--- /dev/null
+++ b/js/public/friend/DOMProxy.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Specify information about DOMProxy proxies in the DOM, for use by ICs.
+ *
+ * Embedders who don't need to define particularly high-performance proxies that
+ * can have random properties added to them can ignore this header.
+ */
+
+#ifndef js_friend_DOMProxy_h
+#define js_friend_DOMProxy_h
+
+#include <stddef.h>  // size_t
+#include <stdint.h>  // uint64_t
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/Id.h"          // JS::PropertyKey
+#include "js/RootingAPI.h"  // JS::Handle, JS::Heap
+#include "js/Value.h"       // JS::UndefinedValue, JS::Value
+
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+
+namespace JS {
+
+/*
+ * The DOMProxyShadowsCheck function will be called to check if the property for
+ * id should be gotten from the prototype, or if there is an own property that
+ * shadows it.
+ * * If ShadowsViaDirectExpando is returned, then the slot at
+ *   listBaseExpandoSlot contains an expando object which has the property in
+ *   question.
+ * * If ShadowsViaIndirectExpando is returned, then the slot at
+ *   listBaseExpandoSlot contains a private pointer to an ExpandoAndGeneration
+ *   and the expando object in the ExpandoAndGeneration has the property in
+ *   question.
+ * * If DoesntShadow is returned then the slot at listBaseExpandoSlot should
+ *   either be undefined or point to an expando object that would contain the
+ *   own property.
+ * * If DoesntShadowUnique is returned then the slot at listBaseExpandoSlot
+ *   should contain a private pointer to a ExpandoAndGeneration, which contains
+ *   a JS::Value that should either be undefined or point to an expando object,
+ *   and a uint64 value. If that value changes then the IC for getting a
+ *   property will be invalidated.
+ * * If Shadows is returned, that means the property is an own property of the
+ *   proxy but doesn't live on the expando object.
+ */
+
+struct ExpandoAndGeneration {
+  ExpandoAndGeneration() : expando(JS::UndefinedValue()), generation(0) {}
+
+  void OwnerUnlinked() { ++generation; }
+
+  static constexpr size_t offsetOfExpando() {
+    return offsetof(ExpandoAndGeneration, expando);
+  }
+
+  static constexpr size_t offsetOfGeneration() {
+    return offsetof(ExpandoAndGeneration, generation);
+  }
+
+  Heap<Value> expando;
+  uint64_t generation;
+};
+
+enum class DOMProxyShadowsResult {
+  ShadowCheckFailed,
+  Shadows,
+  DoesntShadow,
+  DoesntShadowUnique,
+  ShadowsViaDirectExpando,
+  ShadowsViaIndirectExpando
+};
+
+using DOMProxyShadowsCheck = DOMProxyShadowsResult (*)(JSContext*,
+                                                       Handle<JSObject*>,
+                                                       Handle<JS::PropertyKey>);
+
+extern JS_PUBLIC_API void SetDOMProxyInformation(
+    const void* domProxyHandlerFamily,
+    DOMProxyShadowsCheck domProxyShadowsCheck,
+    const void* domRemoteProxyHandlerFamily);
+
+}  // namespace JS
+
+#endif  // js_friend_DOMProxy_h
diff --git a/js/public/friend/DumpFunctions.h b/js/public/friend/DumpFunctions.h
new file mode 100644
index 0000000000..3b69277edc
--- /dev/null
+++ b/js/public/friend/DumpFunctions.h
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Functions to print out values during debugging. */
+
+#ifndef js_friend_DumpFunctions_h
+#define js_friend_DumpFunctions_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MemoryReporting.h"  // mozilla::MallocSizeOf
+
+#include <stddef.h>  // size_t
+#include <stdio.h>   // FILE
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/Printer.h"  // js::GenericPrinter
+#include "js/Utility.h"  // JS::UniqueChars
+
+class JS_PUBLIC_API JSAtom;
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+class JS_PUBLIC_API JSScript;
+class JS_PUBLIC_API JSString;
+
+namespace JS {
+
+class JS_PUBLIC_API BigInt;
+class JS_PUBLIC_API PropertyKey;
+class JS_PUBLIC_API Value;
+
+}  // namespace JS
+
+namespace js {
+
+class InterpreterFrame;
+
+}  // namespace js
+
+namespace JS {
+
+/** Exposed for DumpJSStack */
+extern JS_PUBLIC_API JS::UniqueChars FormatStackDump(JSContext* cx,
+                                                     bool showArgs,
+                                                     bool showLocals,
+                                                     bool showThisProps);
+
+}  // namespace JS
+
+namespace js {
+
+/*
+ * These functions are FRIEND_API to help the debugger find them and to support
+ * temporarily hacking js::Dump* calls into other code.  Note that there are
+ * overloads that do not require the FILE* parameter, which will default to
+ * stderr.
+ *
+ * These functions are no-ops unless built with DEBUG or JS_JITSPEW.
+ */
+
+extern JS_PUBLIC_API void DumpString(JSString* str, FILE* fp);
+
+extern JS_PUBLIC_API void DumpAtom(JSAtom* atom, FILE* fp);
+
+extern JS_PUBLIC_API void DumpObject(JSObject* obj, FILE* fp);
+
+extern JS_PUBLIC_API void DumpChars(const char16_t* s, size_t n, FILE* fp);
+
+// DumpBigInt() outputs the value in decimal if it fits within a 64-bit int, and
+// otherwise in hex, prefixed with "0x". In both cases the "n" is appended.
+extern JS_PUBLIC_API void DumpBigInt(JS::BigInt* bi, FILE* fp);
+
+extern JS_PUBLIC_API void DumpValue(const JS::Value& val, FILE* fp);
+
+extern JS_PUBLIC_API void DumpId(JS::PropertyKey id, FILE* fp);
+
+extern JS_PUBLIC_API bool DumpPC(JSContext* cx, FILE* fp);
+
+extern JS_PUBLIC_API bool DumpScript(JSContext* cx, JSScript* scriptArg,
+                                     FILE* fp);
+
+// Versions for use directly in a debugger (default parameters are not handled
+// well in gdb; built-in handles like stderr are not handled well in lldb.)
+extern JS_PUBLIC_API void DumpString(JSString* str);
+extern JS_PUBLIC_API void DumpAtom(JSAtom* atom);
+extern JS_PUBLIC_API void DumpObject(JSObject* obj);
+extern JS_PUBLIC_API void DumpChars(const char16_t* s, size_t n);
+extern JS_PUBLIC_API void DumpBigInt(JS::BigInt* bi);
+extern JS_PUBLIC_API void DumpValue(const JS::Value& val);
+extern JS_PUBLIC_API void DumpId(JS::PropertyKey id);
+extern JS_PUBLIC_API void DumpInterpreterFrame(
+    JSContext* cx, InterpreterFrame* start = nullptr);
+extern JS_PUBLIC_API bool DumpPC(JSContext* cx);
+extern JS_PUBLIC_API bool DumpScript(JSContext* cx, JSScript* scriptArg);
+
+// DumpBacktrace(), unlike the other dump functions, always dumps a backtrace --
+// regardless of DEBUG or JS_JITSPEW.
+
+extern JS_PUBLIC_API void DumpBacktrace(JSContext* cx, FILE* fp);
+
+extern JS_PUBLIC_API void DumpBacktrace(JSContext* cx, GenericPrinter& out);
+
+extern JS_PUBLIC_API void DumpBacktrace(JSContext* cx);
+
+enum DumpHeapNurseryBehaviour {
+  CollectNurseryBeforeDump,
+  IgnoreNurseryObjects
+};
+
+/**
+ * Dump the complete object graph of heap-allocated things.
+ * fp is the file for the dump output.
+ */
+extern JS_PUBLIC_API void DumpHeap(
+    JSContext* cx, FILE* fp, DumpHeapNurseryBehaviour nurseryBehaviour,
+    mozilla::MallocSizeOf mallocSizeOf = nullptr);
+
+extern JS_PUBLIC_API void DumpFmt(FILE* fp, const char* fmt, ...)
+    MOZ_FORMAT_PRINTF(2, 3);
+extern JS_PUBLIC_API void DumpFmt(const char* fmt, ...) MOZ_FORMAT_PRINTF(1, 2);
+
+}  // namespace js
+
+#endif  // js_friend_DumpFunctions_h
diff --git a/js/public/friend/ErrorMessages.h b/js/public/friend/ErrorMessages.h
new file mode 100644
index 0000000000..1615c8e052
--- /dev/null
+++ b/js/public/friend/ErrorMessages.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * SpiderMonkey internal error numbering and error-formatting functionality
+ * (also for warnings).
+ *
+ * This functionality is moderately stable.  JSErrNum and js::GetErrorMessage
+ * are widely used inside SpiderMonkey, and Gecko uses them to produce errors
+ * identical to those SpiderMonkey itself would produce, in various situations.
+ * However, the set of error numbers is not stable, error number values are not
+ * stable, error types are not stable, etc.  Use your own error reporting code
+ * if you can.
+ */
+
+#ifndef js_friend_ErrorMessages_h
+#define js_friend_ErrorMessages_h
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+struct JSErrorFormatString;
+
+enum JSErrNum {
+#define MSG_DEF(name, count, exception, format) name,
+#include "js/friend/ErrorNumbers.msg"
+#undef MSG_DEF
+  JSErr_Limit
+};
+
+namespace js {
+
+/**
+ * A JSErrorCallback suitable for passing to |JS_ReportErrorNumberASCII| and
+ * similar functions in concert with one of the |JSErrNum| error numbers.
+ *
+ * This function is a function only of |errorNumber|: |userRef| and ambient
+ * state have no effect on its behavior.
+ */
+extern JS_PUBLIC_API const JSErrorFormatString* GetErrorMessage(
+    void* userRef, unsigned errorNumber);
+
+}  // namespace js
+
+#endif  // js_friend_ErrorMessages_h
diff --git a/js/public/friend/ErrorNumbers.msg b/js/public/friend/ErrorNumbers.msg
new file mode 100644
index 0000000000..47f6e640f8
--- /dev/null
+++ b/js/public/friend/ErrorNumbers.msg
@@ -0,0 +1,821 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * SpiderMonkey error messages.
+ *
+ * These are largely for internal use, but they're exposed publicly as a
+ * "friend" interface for embedders that want to replicate SpiderMonkey's exact
+ * error message behavior in particular circumstances.  All names, arities,
+ * types, and messages are subject to change or removal.  However, the
+ * longer-lived the error message, the less likely it is to change.
+ */
+
+/*
+ * This is the JavaScript error message file.
+ *
+ * The format for each JS error message is:
+ *
+ * MSG_DEF(<SYMBOLIC_NAME>, <ARGUMENT_COUNT>, <EXCEPTION_NAME>,
+ *         <FORMAT_STRING>)
+ *
+ * where ;
+ * <SYMBOLIC_NAME> is a legal C identifer that will be used in the
+ * JS engine source.
+ *
+ * <ARGUMENT_COUNT> is an integer literal specifying the total number of
+ * replaceable arguments in the following format string.
+ *
+ * <EXCEPTION_NAME> is an enum JSExnType value, defined in js/ErrorReport.h.
+ *
+ * <FORMAT_STRING> is a string literal, optionally containing sequences
+ * {X} where X  is an integer representing the argument number that will
+ * be replaced with a string value when the error is reported.
+ *
+ * e.g.
+ *
+ * MSG_DEF(JSMSG_NOT_A_SUBSPECIES, 2, JSEXN_TYPEERROR,
+ *         "{0} is not a member of the {1} family")
+ *
+ * can be used:
+ *
+ * JS_ReportErrorNumberASCII(JSMSG_NOT_A_SUBSPECIES, "Rhino", "Monkey");
+ *
+ * to report:
+ *
+ * "TypeError: Rhino is not a member of the Monkey family"
+ */
+
+// clang-format off
+MSG_DEF(JSMSG_NOT_AN_ERROR,            0, JSEXN_ERR, "<Error #0 is reserved>")
+MSG_DEF(JSMSG_NOT_DEFINED,             1, JSEXN_REFERENCEERR, "{0} is not defined")
+MSG_DEF(JSMSG_MORE_ARGS_NEEDED,        4, JSEXN_TYPEERR, "{0}: At least {1} argument{2} required, but only {3} passed")
+MSG_DEF(JSMSG_INCOMPATIBLE_PROTO,      3, JSEXN_TYPEERR, "{0}.prototype.{1} called on incompatible {2}")
+MSG_DEF(JSMSG_INCOMPATIBLE_PROTO2,     3, JSEXN_TYPEERR, "{0}.prototype[{1}] called on incompatible {2}")
+MSG_DEF(JSMSG_NO_CONSTRUCTOR,          1, JSEXN_TYPEERR, "{0} has no constructor")
+MSG_DEF(JSMSG_BAD_SORT_ARG,            0, JSEXN_TYPEERR, "invalid Array.prototype.sort argument")
+MSG_DEF(JSMSG_BAD_TOSORTED_ARG,      0, JSEXN_TYPEERR, "non-function passed to Array.prototype.toSorted")
+MSG_DEF(JSMSG_READ_ONLY,               1, JSEXN_TYPEERR, "{0} is read-only")
+MSG_DEF(JSMSG_CANT_DELETE,             1, JSEXN_TYPEERR, "property {0} is non-configurable and can't be deleted")
+MSG_DEF(JSMSG_CANT_TRUNCATE_ARRAY,     0, JSEXN_TYPEERR, "can't delete non-configurable array element")
+MSG_DEF(JSMSG_NOT_FUNCTION,            1, JSEXN_TYPEERR, "{0} is not a function")
+MSG_DEF(JSMSG_PROPERTY_NOT_CALLABLE,   1, JSEXN_TYPEERR, "{0} property is not callable")
+MSG_DEF(JSMSG_NOT_CONSTRUCTOR,         1, JSEXN_TYPEERR, "{0} is not a constructor")
+MSG_DEF(JSMSG_BOGUS_CONSTRUCTOR,       1, JSEXN_TYPEERR, "{0} constructor can't be used directly")
+MSG_DEF(JSMSG_CANT_CONVERT_TO,         2, JSEXN_TYPEERR, "can't convert {0} to {1}")
+MSG_DEF(JSMSG_TOPRIMITIVE_NOT_CALLABLE, 2, JSEXN_TYPEERR, "can't convert {0} to {1}: its [Symbol.toPrimitive] property is not a function")
+MSG_DEF(JSMSG_TOPRIMITIVE_RETURNED_OBJECT, 2, JSEXN_TYPEERR, "can't convert {0} to {1}: its [Symbol.toPrimitive] method returned an object")
+MSG_DEF(JSMSG_NO_PROPERTIES,           1, JSEXN_TYPEERR, "{0} has no properties")
+MSG_DEF(JSMSG_PROPERTY_FAIL,           2, JSEXN_TYPEERR, "can't access property {0} of {1}")
+MSG_DEF(JSMSG_PROPERTY_FAIL_EXPR,      3, JSEXN_TYPEERR, "can't access property {0}, {1} is {2}")
+MSG_DEF(JSMSG_BAD_REGEXP_FLAG,         1, JSEXN_SYNTAXERR, "invalid regular expression flag {0}")
+MSG_DEF(JSMSG_INVALID_DATA_VIEW_LENGTH, 0, JSEXN_RANGEERR, "invalid data view length")
+MSG_DEF(JSMSG_OFFSET_LARGER_THAN_FILESIZE, 0, JSEXN_RANGEERR, "offset is larger than filesize")
+MSG_DEF(JSMSG_OFFSET_OUT_OF_BUFFER,    0, JSEXN_RANGEERR, "start offset is outside the bounds of the buffer")
+MSG_DEF(JSMSG_OFFSET_OUT_OF_DATAVIEW,  0, JSEXN_RANGEERR, "offset is outside the bounds of the DataView")
+MSG_DEF(JSMSG_SPREAD_TOO_LARGE,        0, JSEXN_RANGEERR, "array too large due to spread operand(s)")
+MSG_DEF(JSMSG_BAD_WEAKMAP_KEY,         0, JSEXN_TYPEERR, "cannot use the given object as a weak map key")
+MSG_DEF(JSMSG_BAD_GETTER_OR_SETTER,    1, JSEXN_TYPEERR, "invalid {0} usage")
+MSG_DEF(JSMSG_BAD_ARRAY_LENGTH,        0, JSEXN_RANGEERR, "invalid array length")
+MSG_DEF(JSMSG_SOURCE_ARRAY_TOO_LONG,   0, JSEXN_RANGEERR, "source array is too long")
+MSG_DEF(JSMSG_REDECLARED_PREV,         2, JSEXN_NOTE, "Previously declared at line {0}, column {1}")
+MSG_DEF(JSMSG_REDECLARED_VAR,          2, JSEXN_SYNTAXERR, "redeclaration of {0} {1}")
+MSG_DEF(JSMSG_UNDECLARED_VAR,          1, JSEXN_REFERENCEERR, "assignment to undeclared variable {0}")
+MSG_DEF(JSMSG_GET_MISSING_PRIVATE,     0, JSEXN_TYPEERR, "can't access private field or method: object is not the right class")
+MSG_DEF(JSMSG_SET_MISSING_PRIVATE,     0, JSEXN_TYPEERR, "can't set private field: object is not the right class")
+MSG_DEF(JSMSG_GETTER_ONLY,             1, JSEXN_TYPEERR, "setting getter-only property {0}")
+MSG_DEF(JSMSG_PRIVATE_SETTER_ONLY,     0, JSEXN_TYPEERR, "getting private setter-only property")
+MSG_DEF(JSMSG_OVERWRITING_ACCESSOR,    1, JSEXN_TYPEERR, "can't overwrite accessor property {0}")
+MSG_DEF(JSMSG_INVALID_MAP_ITERABLE,    1, JSEXN_TYPEERR, "iterable for {0} should have array-like objects")
+MSG_DEF(JSMSG_NESTING_GENERATOR,       0, JSEXN_TYPEERR, "already executing generator")
+MSG_DEF(JSMSG_INCOMPATIBLE_METHOD,     3, JSEXN_TYPEERR, "{0} {1} called on incompatible {2}")
+MSG_DEF(JSMSG_BAD_SURROGATE_CHAR,      1, JSEXN_TYPEERR, "bad surrogate character {0}")
+MSG_DEF(JSMSG_UTF8_CHAR_TOO_LARGE,     1, JSEXN_TYPEERR, "UTF-8 character {0} too large")
+MSG_DEF(JSMSG_MALFORMED_UTF8_CHAR,     1, JSEXN_TYPEERR, "malformed UTF-8 character sequence at offset {0}")
+MSG_DEF(JSMSG_BUILTIN_CTOR_NO_NEW,     1, JSEXN_TYPEERR, "calling a builtin {0} constructor without new is forbidden")
+MSG_DEF(JSMSG_EMPTY_ARRAY_REDUCE,      0, JSEXN_TYPEERR, "reduce of empty array with no initial value")
+MSG_DEF(JSMSG_EMPTY_ITERATOR_REDUCE,   0, JSEXN_TYPEERR, "reduce of empty iterator with no initial value")
+MSG_DEF(JSMSG_UNEXPECTED_TYPE,         2, JSEXN_TYPEERR, "{0} is {1}")
+MSG_DEF(JSMSG_MISSING_FUN_ARG,         2, JSEXN_TYPEERR, "missing argument {0} when calling function {1}")
+MSG_DEF(JSMSG_OBJECT_REQUIRED,         1, JSEXN_TYPEERR, "{0} is not a non-null object")
+MSG_DEF(JSMSG_OBJECT_REQUIRED_ARG,     3, JSEXN_TYPEERR, "{0} argument of {1} must be an object, got {2}")
+MSG_DEF(JSMSG_OBJECT_REQUIRED_WEAKMAP_KEY, 1, JSEXN_TYPEERR, "WeakMap key must be an object, got {0}")
+MSG_DEF(JSMSG_OBJECT_REQUIRED_WEAKSET_VAL, 1, JSEXN_TYPEERR, "WeakSet value must be an object, got {0}")
+MSG_DEF(JSMSG_OBJECT_REQUIRED_PROP_DESC,   1, JSEXN_TYPEERR, "Property descriptor must be an object, got {0}")
+MSG_DEF(JSMSG_OBJECT_REQUIRED_RET_OWNKEYS, 1, JSEXN_TYPEERR, "ownKeys trap must be an object, got {0}")
+MSG_DEF(JSMSG_WRONG_TYPE_ARG,          4, JSEXN_TYPEERR, "argument {0} to {1} must be an object of type {2}, got {3}")
+MSG_DEF(JSMSG_SET_NON_OBJECT_RECEIVER, 2, JSEXN_TYPEERR, "can't assign to property {1} on {0}: not an object")
+MSG_DEF(JSMSG_INVALID_DESCRIPTOR,      0, JSEXN_TYPEERR, "property descriptors must not specify a value or be writable when a getter or setter has been specified")
+MSG_DEF(JSMSG_OBJECT_NOT_EXTENSIBLE,   1, JSEXN_TYPEERR, "{0}: Object is not extensible")
+MSG_DEF(JSMSG_CANT_DEFINE_PROP_OBJECT_NOT_EXTENSIBLE, 2, JSEXN_TYPEERR, "can't define property {1}: {0} is not extensible")
+MSG_DEF(JSMSG_CANT_REDEFINE_PROP,      1, JSEXN_TYPEERR, "can't redefine non-configurable property {0}")
+MSG_DEF(JSMSG_CANT_REDEFINE_ARRAY_LENGTH, 0, JSEXN_TYPEERR, "can't redefine array length")
+MSG_DEF(JSMSG_CANT_DEFINE_PAST_ARRAY_LENGTH, 0, JSEXN_TYPEERR, "can't define array index property past the end of an array with non-writable length")
+MSG_DEF(JSMSG_BAD_GET_SET_FIELD,       1, JSEXN_TYPEERR, "property descriptor's {0} field is neither undefined nor a function")
+MSG_DEF(JSMSG_THROW_TYPE_ERROR,        0, JSEXN_TYPEERR, "'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them")
+MSG_DEF(JSMSG_NOT_EXPECTED_TYPE,       3, JSEXN_TYPEERR, "{0}: expected {1}, got {2}")
+MSG_DEF(JSMSG_NOT_ITERABLE,            1, JSEXN_TYPEERR, "{0} is not iterable")
+MSG_DEF(JSMSG_ALREADY_HAS_PRAGMA,      2, JSEXN_WARN, "{0} is being assigned a {1}, but already has one")
+MSG_DEF(JSMSG_GET_ITER_RETURNED_PRIMITIVE, 0, JSEXN_TYPEERR, "[Symbol.iterator]() returned a non-object value")
+MSG_DEF(JSMSG_ITER_METHOD_RETURNED_PRIMITIVE, 1, JSEXN_TYPEERR, "iterator.{0}() returned a non-object value")
+MSG_DEF(JSMSG_CANT_SET_PROTO,          0, JSEXN_TYPEERR, "can't set prototype of this object")
+MSG_DEF(JSMSG_CANT_SET_PROTO_OF,       1, JSEXN_TYPEERR, "can't set prototype of {0}")
+MSG_DEF(JSMSG_CANT_SET_PROTO_CYCLE,    0, JSEXN_TYPEERR, "can't set prototype: it would cause a prototype chain cycle")
+MSG_DEF(JSMSG_INVALID_ARG_TYPE,        3, JSEXN_TYPEERR, "Invalid type: {0} can't be a{1} {2}")
+MSG_DEF(JSMSG_TERMINATED,              1, JSEXN_ERR, "Script terminated by timeout at:\n{0}")
+MSG_DEF(JSMSG_CANT_CALL_CLASS_CONSTRUCTOR, 0, JSEXN_TYPEERR, "class constructors must be invoked with 'new'")
+MSG_DEF(JSMSG_UNINITIALIZED_THIS,      0, JSEXN_REFERENCEERR, "must call super constructor before using 'this' in derived class constructor")
+MSG_DEF(JSMSG_BAD_DERIVED_RETURN,      1, JSEXN_TYPEERR, "derived class constructor returned invalid value {0}")
+MSG_DEF(JSMSG_BAD_HERITAGE,            2, JSEXN_TYPEERR, "class heritage {0} is {1}")
+MSG_DEF(JSMSG_NOT_OBJORNULL,           1, JSEXN_TYPEERR, "{0} is not an object or null")
+MSG_DEF(JSMSG_CONSTRUCTOR_DISABLED,    1, JSEXN_TYPEERR, "{0} is disabled")
+
+// JSON
+MSG_DEF(JSMSG_JSON_BAD_PARSE,          3, JSEXN_SYNTAXERR, "JSON.parse: {0} at line {1} column {2} of the JSON data")
+MSG_DEF(JSMSG_JSON_CYCLIC_VALUE,       0, JSEXN_TYPEERR, "cyclic object value")
+
+// Runtime errors
+MSG_DEF(JSMSG_ASSIGN_TO_CALL,          0, JSEXN_REFERENCEERR, "cannot assign to function call")
+MSG_DEF(JSMSG_ASSIGN_TO_PRIVATE_METHOD, 0, JSEXN_TYPEERR, "cannot assign to private method")
+MSG_DEF(JSMSG_BAD_INSTANCEOF_RHS,      1, JSEXN_TYPEERR, "invalid 'instanceof' operand {0}")
+MSG_DEF(JSMSG_BAD_PROTOTYPE,           1, JSEXN_TYPEERR, "'prototype' property of {0} is not an object")
+MSG_DEF(JSMSG_IN_NOT_OBJECT,           1, JSEXN_TYPEERR, "right-hand side of 'in' should be an object, got {0}")
+MSG_DEF(JSMSG_IN_STRING,               2, JSEXN_TYPEERR, "cannot use 'in' operator to search for {0} in {1}")
+MSG_DEF(JSMSG_TOO_MANY_CON_SPREADARGS, 0, JSEXN_RANGEERR, "too many constructor arguments")
+MSG_DEF(JSMSG_TOO_MANY_FUN_SPREADARGS, 0, JSEXN_RANGEERR, "too many function arguments")
+MSG_DEF(JSMSG_UNINITIALIZED_LEXICAL,   1, JSEXN_REFERENCEERR, "can't access lexical declaration '{0}' before initialization")
+MSG_DEF(JSMSG_BAD_CONST_ASSIGN,        1, JSEXN_TYPEERR, "invalid assignment to const '{0}'")
+MSG_DEF(JSMSG_CANT_DECLARE_GLOBAL_BINDING, 2, JSEXN_TYPEERR, "cannot declare global binding '{0}': {1}")
+
+// Date
+MSG_DEF(JSMSG_INVALID_DATE,            0, JSEXN_RANGEERR, "invalid date")
+MSG_DEF(JSMSG_BAD_TOISOSTRING_PROP,    0, JSEXN_TYPEERR, "toISOString property is not callable")
+
+// String
+MSG_DEF(JSMSG_BAD_URI,                 0, JSEXN_URIERR, "malformed URI sequence")
+MSG_DEF(JSMSG_INVALID_NORMALIZE_FORM,  0, JSEXN_RANGEERR, "form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD'")
+MSG_DEF(JSMSG_NEGATIVE_REPETITION_COUNT, 0, JSEXN_RANGEERR, "repeat count must be non-negative")
+MSG_DEF(JSMSG_NOT_A_CODEPOINT,         1, JSEXN_RANGEERR, "{0} is not a valid code point")
+MSG_DEF(JSMSG_RESULTING_STRING_TOO_LARGE, 0, JSEXN_RANGEERR, "repeat count must be less than infinity and not overflow maximum string size")
+MSG_DEF(JSMSG_FLAGS_UNDEFINED_OR_NULL, 0, JSEXN_TYPEERR, "'flags' property must neither be undefined nor null")
+MSG_DEF(JSMSG_REQUIRES_GLOBAL_REGEXP,  1, JSEXN_TYPEERR, "{0} must be called with a global RegExp")
+
+// Number
+MSG_DEF(JSMSG_BAD_RADIX,               0, JSEXN_RANGEERR, "radix must be an integer at least 2 and no greater than 36")
+MSG_DEF(JSMSG_PRECISION_RANGE,         1, JSEXN_RANGEERR, "precision {0} out of range")
+
+// Function
+MSG_DEF(JSMSG_BAD_APPLY_ARGS,          1, JSEXN_TYPEERR, "second argument to Function.prototype.{0} must be an array")
+MSG_DEF(JSMSG_DEPRECATED_USAGE,        1, JSEXN_REFERENCEERR, "deprecated {0} usage")
+MSG_DEF(JSMSG_NO_REST_NAME,            0, JSEXN_SYNTAXERR, "no parameter name after ...")
+MSG_DEF(JSMSG_PARAMETER_AFTER_REST,    0, JSEXN_SYNTAXERR, "parameter after rest parameter")
+MSG_DEF(JSMSG_TOO_MANY_ARGUMENTS,      0, JSEXN_RANGEERR, "too many arguments provided for a function call")
+
+// CSP
+MSG_DEF(JSMSG_CSP_BLOCKED_EVAL,        0, JSEXN_EVALERR, "call to eval() blocked by CSP")
+MSG_DEF(JSMSG_CSP_BLOCKED_FUNCTION,    0, JSEXN_EVALERR, "call to Function() blocked by CSP")
+MSG_DEF(JSMSG_CSP_BLOCKED_WASM,        1, JSEXN_WASMCOMPILEERROR, "call to {0}() blocked by CSP")
+MSG_DEF(JSMSG_CSP_BLOCKED_SHADOWREALM,    0, JSEXN_EVALERR, "call to ShadowRealm.prototype.evaluate blocked by CSP")
+
+// Wrappers
+MSG_DEF(JSMSG_ACCESSOR_DEF_DENIED,     1, JSEXN_ERR, "Permission denied to define accessor property {0}")
+MSG_DEF(JSMSG_DEAD_OBJECT,             0, JSEXN_TYPEERR, "can't access dead object")
+MSG_DEF(JSMSG_OBJECT_ACCESS_DENIED,    0, JSEXN_ERR, "Permission denied to access object")
+MSG_DEF(JSMSG_PROPERTY_ACCESS_DENIED,  1, JSEXN_ERR, "Permission denied to access property {0}")
+
+// JSAPI-only (Not thrown as JS exceptions)
+MSG_DEF(JSMSG_CANT_CLONE_OBJECT,       0, JSEXN_TYPEERR, "can't clone object")
+MSG_DEF(JSMSG_CANT_OPEN,               2, JSEXN_ERR, "can't open {0}: {1}")
+MSG_DEF(JSMSG_SUPPORT_NOT_ENABLED,     1, JSEXN_ERR, "support for {0} is not enabled")
+MSG_DEF(JSMSG_USER_DEFINED_ERROR,      0, JSEXN_ERR, "JS_ReportError was called")
+
+// Internal errors
+MSG_DEF(JSMSG_ALLOC_OVERFLOW,          0, JSEXN_INTERNALERR, "allocation size overflow")
+MSG_DEF(JSMSG_BAD_BYTECODE,            1, JSEXN_INTERNALERR, "unimplemented JavaScript bytecode {0}")
+MSG_DEF(JSMSG_BUFFER_TOO_SMALL,        0, JSEXN_INTERNALERR, "buffer too small")
+MSG_DEF(JSMSG_BYTECODE_TOO_BIG,        2, JSEXN_INTERNALERR, "bytecode {0} too large (limit {1})")
+MSG_DEF(JSMSG_DECODE_FAILURE,          0, JSEXN_INTERNALERR, "failed to decode cache")
+MSG_DEF(JSMSG_NEED_DIET,               1, JSEXN_INTERNALERR, "{0} too large")
+MSG_DEF(JSMSG_OUT_OF_MEMORY,           0, JSEXN_INTERNALERR, "out of memory")
+MSG_DEF(JSMSG_OVER_RECURSED,           0, JSEXN_INTERNALERR, "too much recursion")
+MSG_DEF(JSMSG_TOO_DEEP,                1, JSEXN_INTERNALERR, "{0} nested too deeply")
+MSG_DEF(JSMSG_UNCAUGHT_EXCEPTION,      1, JSEXN_INTERNALERR, "uncaught exception: {0}")
+MSG_DEF(JSMSG_UNKNOWN_FORMAT,          1, JSEXN_INTERNALERR, "unknown bytecode format {0}")
+MSG_DEF(JSMSG_UNSAFE_FILENAME,         1, JSEXN_INTERNALERR, "unsafe filename: {0}")
+
+// Frontend
+MSG_DEF(JSMSG_ACCESSOR_WRONG_ARGS,     3, JSEXN_SYNTAXERR, "{0} functions must have {1} argument{2}")
+MSG_DEF(JSMSG_ARRAY_INIT_TOO_BIG,      0, JSEXN_INTERNALERR, "array initializer too large")
+MSG_DEF(JSMSG_AS_AFTER_IMPORT_STAR,    0, JSEXN_SYNTAXERR, "missing keyword 'as' after import *")
+MSG_DEF(JSMSG_AS_AFTER_RESERVED_WORD,  1, JSEXN_SYNTAXERR, "missing keyword 'as' after reserved word '{0}'")
+MSG_DEF(JSMSG_AS_AFTER_STRING,         0, JSEXN_SYNTAXERR, "missing keyword 'as' after string literal")
+MSG_DEF(JSMSG_AWAIT_IN_PARAMETER,      0, JSEXN_SYNTAXERR, "await expression can't be used in parameter")
+MSG_DEF(JSMSG_AWAIT_OUTSIDE_ASYNC,     0, JSEXN_SYNTAXERR, "await is only valid in async functions and async generators")
+MSG_DEF(JSMSG_AWAIT_OUTSIDE_ASYNC_OR_MODULE, 0, JSEXN_SYNTAXERR, "await is only valid in async functions, async generators and modules")
+MSG_DEF(JSMSG_TOP_LEVEL_AWAIT_NOT_SUPPORTED, 0, JSEXN_SYNTAXERR, "top level await is not supported in this context")
+MSG_DEF(JSMSG_BAD_ARROW_ARGS,          0, JSEXN_SYNTAXERR, "invalid arrow-function arguments (parentheses around the arrow-function may help)")
+MSG_DEF(JSMSG_BAD_COALESCE_MIXING,     0, JSEXN_SYNTAXERR, "cannot use `??` unparenthesized within `||` and `&&` expressions")
+MSG_DEF(JSMSG_BAD_CONST_DECL,          0, JSEXN_SYNTAXERR, "missing = in const declaration")
+MSG_DEF(JSMSG_BAD_CONTINUE,            0, JSEXN_SYNTAXERR, "continue must be inside loop")
+MSG_DEF(JSMSG_BAD_DESTRUCT_ASS,        0, JSEXN_SYNTAXERR, "invalid destructuring assignment operator")
+MSG_DEF(JSMSG_BAD_DESTRUCT_TARGET,     0, JSEXN_SYNTAXERR, "invalid destructuring target")
+MSG_DEF(JSMSG_BAD_DESTRUCT_PARENS,     0, JSEXN_SYNTAXERR, "destructuring patterns in assignments can't be parenthesized")
+MSG_DEF(JSMSG_BAD_DESTRUCT_DECL,       0, JSEXN_SYNTAXERR, "missing = in destructuring declaration")
+MSG_DEF(JSMSG_BAD_DUP_ARGS,            0, JSEXN_SYNTAXERR, "duplicate argument names not allowed in this context")
+MSG_DEF(JSMSG_BAD_FOR_LEFTSIDE,        0, JSEXN_SYNTAXERR, "invalid for-in/of left-hand side")
+MSG_DEF(JSMSG_LEXICAL_DECL_DEFINES_LET,0, JSEXN_SYNTAXERR, "a lexical declaration can't define a 'let' binding")
+MSG_DEF(JSMSG_BAD_STARTING_FOROF_LHS,  1, JSEXN_SYNTAXERR, "an expression X in 'for (X of Y)' must not start with '{0}'")
+MSG_DEF(JSMSG_BAD_INCOP_OPERAND,       0, JSEXN_SYNTAXERR, "invalid increment/decrement operand")
+MSG_DEF(JSMSG_BAD_LEFTSIDE_OF_ASS,     0, JSEXN_SYNTAXERR, "invalid assignment left-hand side")
+MSG_DEF(JSMSG_BAD_LOCAL_STRING_EXPORT, 0, JSEXN_SYNTAXERR, "string exports can't be used without 'from'")
+MSG_DEF(JSMSG_BAD_METHOD_DEF,          0, JSEXN_SYNTAXERR, "bad method definition")
+MSG_DEF(JSMSG_BAD_POW_LEFTSIDE,        0, JSEXN_SYNTAXERR, "unparenthesized unary expression can't appear on the left-hand side of '**'")
+MSG_DEF(JSMSG_BAD_PROP_ID,             0, JSEXN_SYNTAXERR, "invalid property id")
+MSG_DEF(JSMSG_BAD_RETURN_OR_YIELD,     1, JSEXN_SYNTAXERR, "{0} not in function")
+MSG_DEF(JSMSG_BAD_STRICT_ASSIGN,       1, JSEXN_SYNTAXERR, "'{0}' can't be defined or assigned to in strict mode code")
+MSG_DEF(JSMSG_BAD_STRICT_ASSIGN_ARGUMENTS, 0, JSEXN_SYNTAXERR, "'arguments' can't be defined or assigned to in strict mode code")
+MSG_DEF(JSMSG_BAD_STRICT_ASSIGN_EVAL,  0, JSEXN_SYNTAXERR, "'eval' can't be defined or assigned to in strict mode code")
+MSG_DEF(JSMSG_BAD_SWITCH,              0, JSEXN_SYNTAXERR, "invalid switch statement")
+MSG_DEF(JSMSG_BAD_SUPER,               0, JSEXN_SYNTAXERR, "invalid use of keyword 'super'")
+MSG_DEF(JSMSG_BAD_SUPERPROP,           1, JSEXN_SYNTAXERR, "use of super {0} accesses only valid within methods or eval code within methods")
+MSG_DEF(JSMSG_BAD_SUPERPRIVATE,        0, JSEXN_SYNTAXERR, "invalid access of private field on 'super'")
+MSG_DEF(JSMSG_BAD_SUPERCALL,           0, JSEXN_SYNTAXERR, "super() is only valid in derived class constructors")
+MSG_DEF(JSMSG_BAD_ARGUMENTS,           0, JSEXN_SYNTAXERR, "arguments is not valid in fields")
+MSG_DEF(JSMSG_BRACKET_AFTER_LIST,      0, JSEXN_SYNTAXERR, "missing ] after element list")
+MSG_DEF(JSMSG_BRACKET_IN_INDEX,        0, JSEXN_SYNTAXERR, "missing ] in index expression")
+MSG_DEF(JSMSG_BRACKET_OPENED,          2, JSEXN_NOTE, "[ opened at line {0}, column {1}")
+MSG_DEF(JSMSG_CATCH_IDENTIFIER,        0, JSEXN_SYNTAXERR, "missing identifier in catch")
+MSG_DEF(JSMSG_CATCH_OR_FINALLY,        0, JSEXN_SYNTAXERR, "missing catch or finally after try")
+MSG_DEF(JSMSG_CATCH_WITHOUT_TRY,       0, JSEXN_SYNTAXERR, "catch without try")
+MSG_DEF(JSMSG_COLON_AFTER_CASE,        0, JSEXN_SYNTAXERR, "missing : after case label")
+MSG_DEF(JSMSG_COLON_AFTER_ID,          0, JSEXN_SYNTAXERR, "missing : after property id")
+MSG_DEF(JSMSG_COLON_IN_COND,           0, JSEXN_SYNTAXERR, "missing : in conditional expression")
+MSG_DEF(JSMSG_COMP_PROP_UNTERM_EXPR,   0, JSEXN_SYNTAXERR, "missing ] in computed property name")
+MSG_DEF(JSMSG_CURLY_AFTER_BODY,        0, JSEXN_SYNTAXERR, "missing } after function body")
+MSG_DEF(JSMSG_CURLY_OPENED,            2, JSEXN_NOTE, "{ opened at line {0}, column {1}")
+MSG_DEF(JSMSG_CURLY_AFTER_CATCH,       0, JSEXN_SYNTAXERR, "missing } after catch block")
+MSG_DEF(JSMSG_CURLY_AFTER_FINALLY,     0, JSEXN_SYNTAXERR, "missing } after finally block")
+MSG_DEF(JSMSG_CURLY_AFTER_LIST,        0, JSEXN_SYNTAXERR, "missing } after property list")
+MSG_DEF(JSMSG_CURLY_AFTER_TRY,         0, JSEXN_SYNTAXERR, "missing } after try block")
+MSG_DEF(JSMSG_CURLY_BEFORE_BODY,       0, JSEXN_SYNTAXERR, "missing { before function body")
+MSG_DEF(JSMSG_CURLY_BEFORE_CATCH,      0, JSEXN_SYNTAXERR, "missing { before catch block")
+MSG_DEF(JSMSG_CURLY_BEFORE_CLASS,      0, JSEXN_SYNTAXERR, "missing { before class body")
+MSG_DEF(JSMSG_CURLY_BEFORE_FINALLY,    0, JSEXN_SYNTAXERR, "missing { before finally block")
+MSG_DEF(JSMSG_CURLY_BEFORE_SWITCH,     0, JSEXN_SYNTAXERR, "missing { before switch body")
+MSG_DEF(JSMSG_CURLY_BEFORE_TRY,        0, JSEXN_SYNTAXERR, "missing { before try block")
+MSG_DEF(JSMSG_CURLY_IN_COMPOUND,       0, JSEXN_SYNTAXERR, "missing } in compound statement")
+MSG_DEF(JSMSG_DECLARATION_AFTER_EXPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'export' keyword")
+MSG_DEF(JSMSG_DECLARATION_AFTER_IMPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'import' keyword")
+MSG_DEF(JSMSG_DEPRECATED_DELETE_OPERAND, 0, JSEXN_SYNTAXERR, "applying the 'delete' operator to an unqualified name is deprecated")
+MSG_DEF(JSMSG_DEPRECATED_OCTAL_LITERAL,0, JSEXN_SYNTAXERR, "\"0\"-prefixed octal literals are deprecated; use the \"0o\" prefix instead")
+MSG_DEF(JSMSG_DEPRECATED_OCTAL_ESCAPE ,0, JSEXN_SYNTAXERR, "octal escape sequences can't be used in untagged template literals or in strict mode code")
+MSG_DEF(JSMSG_DEPRECATED_EIGHT_OR_NINE_ESCAPE, 0, JSEXN_SYNTAXERR, "the escapes \\8 and \\9 can't be used in untagged template literals or in strict mode code")
+MSG_DEF(JSMSG_DEPRECATED_PRAGMA,       1, JSEXN_WARN, "Using //@ to indicate {0} pragmas is deprecated. Use //# instead")
+MSG_DEF(JSMSG_DUPLICATE_EXPORT_NAME,   1, JSEXN_SYNTAXERR, "duplicate export name '{0}'")
+MSG_DEF(JSMSG_DUPLICATE_FORMAL,        1, JSEXN_SYNTAXERR, "duplicate formal argument {0}")
+MSG_DEF(JSMSG_DUPLICATE_LABEL,         0, JSEXN_SYNTAXERR, "duplicate label")
+MSG_DEF(JSMSG_DUPLICATE_PROPERTY,      1, JSEXN_SYNTAXERR, "property name {0} appears more than once in object literal")
+MSG_DEF(JSMSG_DUPLICATE_PROTO_PROPERTY, 0, JSEXN_SYNTAXERR, "property name __proto__ appears more than once in object literal")
+MSG_DEF(JSMSG_EQUAL_AS_ASSIGN,         0, JSEXN_SYNTAXERR, "test for equality (==) mistyped as assignment (=)?")
+MSG_DEF(JSMSG_EXPORT_DECL_AT_TOP_LEVEL,0, JSEXN_SYNTAXERR, "export declarations may only appear at top level of a module")
+MSG_DEF(JSMSG_FINALLY_WITHOUT_TRY,     0, JSEXN_SYNTAXERR, "finally without try")
+MSG_DEF(JSMSG_FORBIDDEN_AS_STATEMENT,  1, JSEXN_SYNTAXERR, "{0} can't appear in single-statement context")
+MSG_DEF(JSMSG_FOR_AWAIT_OUTSIDE_ASYNC, 0, JSEXN_SYNTAXERR, "for await (... of ...) is only valid in async functions and async generators")
+MSG_DEF(JSMSG_FROM_AFTER_IMPORT_CLAUSE, 0, JSEXN_SYNTAXERR, "missing keyword 'from' after import clause")
+MSG_DEF(JSMSG_FROM_AFTER_EXPORT_STAR,  0, JSEXN_SYNTAXERR, "missing keyword 'from' after export *")
+MSG_DEF(JSMSG_GARBAGE_AFTER_INPUT,     2, JSEXN_SYNTAXERR, "unexpected garbage after {0}, starting with {1}")
+MSG_DEF(JSMSG_IDSTART_AFTER_NUMBER,    0, JSEXN_SYNTAXERR, "identifier starts immediately after numeric literal")
+MSG_DEF(JSMSG_BAD_ESCAPE,              0, JSEXN_SYNTAXERR, "invalid escape sequence")
+MSG_DEF(JSMSG_MISSING_PRIVATE_NAME,    0, JSEXN_SYNTAXERR, "'#' not followed by identifier")
+MSG_DEF(JSMSG_PRIVATE_DELETE,          0, JSEXN_SYNTAXERR, "private fields can't be deleted")
+MSG_DEF(JSMSG_MISSING_PRIVATE_DECL,    1, JSEXN_SYNTAXERR, "reference to undeclared private field or method {0}")
+MSG_DEF(JSMSG_ILLEGAL_CHARACTER,       1, JSEXN_SYNTAXERR, "illegal character {0}")
+MSG_DEF(JSMSG_IMPORT_META_OUTSIDE_MODULE, 0, JSEXN_SYNTAXERR, "import.meta may only appear in a module")
+MSG_DEF(JSMSG_IMPORT_DECL_AT_TOP_LEVEL, 0, JSEXN_SYNTAXERR, "import declarations may only appear at top level of a module")
+MSG_DEF(JSMSG_OF_AFTER_FOR_LOOP_DECL,  0, JSEXN_SYNTAXERR, "a declaration in the head of a for-of loop can't have an initializer")
+MSG_DEF(JSMSG_IN_AFTER_LEXICAL_FOR_DECL,0,JSEXN_SYNTAXERR, "a lexical declaration in the head of a for-in loop can't have an initializer")
+MSG_DEF(JSMSG_INVALID_FOR_IN_DECL_WITH_INIT,0,JSEXN_SYNTAXERR,"for-in loop head declarations may not have initializers")
+MSG_DEF(JSMSG_INVALID_ID,              1, JSEXN_SYNTAXERR, "{0} is an invalid identifier")
+MSG_DEF(JSMSG_SEPARATOR_IN_ZERO_PREFIXED_NUMBER, 0, JSEXN_SYNTAXERR, "numeric separators '_' are not allowed in numbers that start with '0'")
+MSG_DEF(JSMSG_LABEL_NOT_FOUND,         0, JSEXN_SYNTAXERR, "label not found")
+MSG_DEF(JSMSG_GENERATOR_LABEL,         0, JSEXN_SYNTAXERR, "generator functions cannot be labelled")
+MSG_DEF(JSMSG_FUNCTION_LABEL,          0, JSEXN_SYNTAXERR, "functions cannot be labelled")
+MSG_DEF(JSMSG_SLOPPY_FUNCTION_LABEL,   0, JSEXN_SYNTAXERR, "functions can only be labelled inside blocks")
+MSG_DEF(JSMSG_LINE_BREAK_AFTER_THROW,  0, JSEXN_SYNTAXERR, "no line break is allowed between 'throw' and its expression")
+MSG_DEF(JSMSG_MALFORMED_ESCAPE,        1, JSEXN_SYNTAXERR, "malformed {0} character escape sequence")
+MSG_DEF(JSMSG_MISSING_BINARY_DIGITS,   0, JSEXN_SYNTAXERR, "missing binary digits after '0b'")
+MSG_DEF(JSMSG_MISSING_EXPONENT,        0, JSEXN_SYNTAXERR, "missing exponent")
+MSG_DEF(JSMSG_MISSING_EXPR_AFTER_THROW,0, JSEXN_SYNTAXERR, "throw statement is missing an expression")
+MSG_DEF(JSMSG_MISSING_FORMAL,          0, JSEXN_SYNTAXERR, "missing formal parameter")
+MSG_DEF(JSMSG_MISSING_HEXDIGITS,       0, JSEXN_SYNTAXERR, "missing hexadecimal digits after '0x'")
+MSG_DEF(JSMSG_MISSING_OCTAL_DIGITS,    0, JSEXN_SYNTAXERR, "missing octal digits after '0o'")
+MSG_DEF(JSMSG_NUMBER_END_WITH_UNDERSCORE, 0, JSEXN_SYNTAXERR, "underscore can appear only between digits, not after the last digit in a number")
+MSG_DEF(JSMSG_NUMBER_MULTIPLE_ADJACENT_UNDERSCORES, 0, JSEXN_SYNTAXERR, "number cannot contain multiple adjacent underscores")
+MSG_DEF(JSMSG_MODULE_SPEC_AFTER_FROM,  0, JSEXN_SYNTAXERR, "missing module specifier after 'from' keyword")
+MSG_DEF(JSMSG_NAME_AFTER_DOT,          0, JSEXN_SYNTAXERR, "missing name after . operator")
+MSG_DEF(JSMSG_NAMED_IMPORTS_OR_NAMESPACE_IMPORT, 0, JSEXN_SYNTAXERR, "expected named imports or namespace import after comma")
+MSG_DEF(JSMSG_NO_BINDING_NAME,        0, JSEXN_SYNTAXERR, "missing binding name")
+MSG_DEF(JSMSG_NO_EXPORT_NAME,          0, JSEXN_SYNTAXERR, "missing export name")
+MSG_DEF(JSMSG_NO_IMPORT_NAME,          0, JSEXN_SYNTAXERR, "missing import name")
+MSG_DEF(JSMSG_NO_VARIABLE_NAME,        0, JSEXN_SYNTAXERR, "missing variable name")
+MSG_DEF(JSMSG_PAREN_AFTER_ARGS,        0, JSEXN_SYNTAXERR, "missing ) after argument list")
+MSG_DEF(JSMSG_PAREN_AFTER_CATCH,       0, JSEXN_SYNTAXERR, "missing ) after catch")
+MSG_DEF(JSMSG_PAREN_AFTER_COND,        0, JSEXN_SYNTAXERR, "missing ) after condition")
+MSG_DEF(JSMSG_PAREN_AFTER_FOR,         0, JSEXN_SYNTAXERR, "missing ( after for")
+MSG_DEF(JSMSG_PAREN_AFTER_FORMAL,      0, JSEXN_SYNTAXERR, "missing ) after formal parameters")
+MSG_DEF(JSMSG_PAREN_AFTER_FOR_CTRL,    0, JSEXN_SYNTAXERR, "missing ) after for-loop control")
+MSG_DEF(JSMSG_PAREN_AFTER_SWITCH,      0, JSEXN_SYNTAXERR, "missing ) after switch expression")
+MSG_DEF(JSMSG_PAREN_AFTER_WITH,        0, JSEXN_SYNTAXERR, "missing ) after with-statement object")
+MSG_DEF(JSMSG_PAREN_BEFORE_CATCH,      0, JSEXN_SYNTAXERR, "missing ( before catch")
+MSG_DEF(JSMSG_PAREN_BEFORE_COND,       0, JSEXN_SYNTAXERR, "missing ( before condition")
+MSG_DEF(JSMSG_PAREN_BEFORE_FORMAL,     0, JSEXN_SYNTAXERR, "missing ( before formal parameters")
+MSG_DEF(JSMSG_PAREN_BEFORE_SWITCH,     0, JSEXN_SYNTAXERR, "missing ( before switch expression")
+MSG_DEF(JSMSG_PAREN_BEFORE_WITH,       0, JSEXN_SYNTAXERR, "missing ( before with-statement object")
+MSG_DEF(JSMSG_PAREN_IN_PAREN,          0, JSEXN_SYNTAXERR, "missing ) in parenthetical")
+MSG_DEF(JSMSG_PAREN_AFTER_DECORATOR,   0, JSEXN_SYNTAXERR, "missing ) in decorator expression")
+MSG_DEF(JSMSG_RC_AFTER_EXPORT_SPEC_LIST, 0, JSEXN_SYNTAXERR, "missing '}' after export specifier list")
+MSG_DEF(JSMSG_RC_AFTER_IMPORT_SPEC_LIST, 0, JSEXN_SYNTAXERR, "missing '}' after module specifier list")
+MSG_DEF(JSMSG_RESERVED_ID,             1, JSEXN_SYNTAXERR, "{0} is a reserved identifier")
+MSG_DEF(JSMSG_REST_WITH_COMMA,         0, JSEXN_SYNTAXERR, "rest element may not have a trailing comma")
+MSG_DEF(JSMSG_REST_WITH_DEFAULT,       0, JSEXN_SYNTAXERR, "rest parameter may not have a default")
+MSG_DEF(JSMSG_SELFHOSTED_METHOD_CALL,  0, JSEXN_SYNTAXERR, "self-hosted code may not contain direct method calls. Use callFunction() or callContentFunction()")
+MSG_DEF(JSMSG_SEMI_AFTER_FOR_COND,     0, JSEXN_SYNTAXERR, "missing ; after for-loop condition")
+MSG_DEF(JSMSG_SEMI_AFTER_FOR_INIT,     0, JSEXN_SYNTAXERR, "missing ; after for-loop initializer")
+MSG_DEF(JSMSG_SOURCE_TOO_LONG,         0, JSEXN_RANGEERR, "source is too long")
+MSG_DEF(JSMSG_STMT_AFTER_RETURN,       0, JSEXN_WARN, "unreachable code after return statement")
+MSG_DEF(JSMSG_STRICT_CODE_WITH,        0, JSEXN_SYNTAXERR, "strict mode code may not contain 'with' statements")
+MSG_DEF(JSMSG_STRICT_NON_SIMPLE_PARAMS, 1, JSEXN_SYNTAXERR, "\"use strict\" not allowed in function with {0} parameter")
+MSG_DEF(JSMSG_TEMPLSTR_UNTERM_EXPR,    0, JSEXN_SYNTAXERR, "missing } in template string")
+MSG_DEF(JSMSG_TOO_MANY_CASES,          0, JSEXN_INTERNALERR, "too many switch cases")
+MSG_DEF(JSMSG_TOO_MANY_CON_ARGS,       0, JSEXN_SYNTAXERR, "too many constructor arguments")
+MSG_DEF(JSMSG_TOO_MANY_DEFAULTS,       0, JSEXN_SYNTAXERR, "more than one switch default")
+MSG_DEF(JSMSG_TOO_MANY_FUN_ARGS,       0, JSEXN_SYNTAXERR, "too many function arguments")
+MSG_DEF(JSMSG_TOO_MANY_LOCALS,         0, JSEXN_SYNTAXERR, "too many local variables")
+MSG_DEF(JSMSG_TOO_MANY_RESUME_INDEXES, 0, JSEXN_SYNTAXERR, "too many yield/await/finally/case locations")
+MSG_DEF(JSMSG_TOUGH_BREAK,             0, JSEXN_SYNTAXERR, "unlabeled break must be inside loop or switch")
+MSG_DEF(JSMSG_UNEXPECTED_TOKEN,        2, JSEXN_SYNTAXERR, "expected {0}, got {1}")
+MSG_DEF(JSMSG_UNEXPECTED_TOKEN_NO_EXPECT,  1, JSEXN_SYNTAXERR, "unexpected token: {0}")
+MSG_DEF(JSMSG_UNEXPECTED_PARAMLIST_END,0, JSEXN_SYNTAXERR, "unexpected end of function parameter list")
+MSG_DEF(JSMSG_UNNAMED_CLASS_STMT,      0, JSEXN_SYNTAXERR, "class statement requires a name")
+MSG_DEF(JSMSG_UNNAMED_FUNCTION_STMT,   0, JSEXN_SYNTAXERR, "function statement requires a name")
+MSG_DEF(JSMSG_UNPAIRED_SURROGATE_EXPORT, 0, JSEXN_SYNTAXERR, "module export name contains unpaired surrogate")
+MSG_DEF(JSMSG_UNTERMINATED_COMMENT,    0, JSEXN_SYNTAXERR, "unterminated comment")
+MSG_DEF(JSMSG_UNTERMINATED_REGEXP,     0, JSEXN_SYNTAXERR, "unterminated regular expression literal")
+MSG_DEF(JSMSG_UNTERMINATED_STATIC_CLASS_BLOCK, 0, JSEXN_SYNTAXERR, "unterminated static class block")
+MSG_DEF(JSMSG_EOF_BEFORE_END_OF_LITERAL,1,JSEXN_SYNTAXERR, "{0} literal not terminated before end of script")
+MSG_DEF(JSMSG_EOL_BEFORE_END_OF_STRING,1, JSEXN_SYNTAXERR, "{0} string literal contains an unescaped line break")
+MSG_DEF(JSMSG_EOF_IN_ESCAPE_IN_LITERAL,1, JSEXN_SYNTAXERR, "reached end of script in the middle of an escape sequence in a {0} literal")
+MSG_DEF(JSMSG_USE_ASM_DIRECTIVE_FAIL,  0, JSEXN_SYNTAXERR, "\"use asm\" is only meaningful in the Directive Prologue of a function body")
+MSG_DEF(JSMSG_VAR_HIDES_ARG,           1, JSEXN_TYPEERR, "variable {0} redeclares argument")
+MSG_DEF(JSMSG_WHILE_AFTER_DO,          0, JSEXN_SYNTAXERR, "missing while after do-loop body")
+MSG_DEF(JSMSG_YIELD_IN_PARAMETER,      0, JSEXN_SYNTAXERR, "yield expression can't be used in parameter")
+MSG_DEF(JSMSG_YIELD_OUTSIDE_GENERATOR, 0, JSEXN_SYNTAXERR, "yield expression is only valid in generators")
+MSG_DEF(JSMSG_BAD_COLUMN_NUMBER,       0, JSEXN_RANGEERR, "column number out of range")
+MSG_DEF(JSMSG_BAD_LINE_NUMBER,         0, JSEXN_RANGEERR, "line number out of range")
+MSG_DEF(JSMSG_BAD_NEWTARGET,           0, JSEXN_SYNTAXERR, "new.target only allowed within functions")
+MSG_DEF(JSMSG_BAD_NEW_OPTIONAL,        0, JSEXN_SYNTAXERR, "new keyword cannot be used with an optional chain")
+MSG_DEF(JSMSG_BAD_OPTIONAL_TEMPLATE,   0, JSEXN_SYNTAXERR, "tagged template cannot be used with optional chain")
+MSG_DEF(JSMSG_IMPORT_ASSERTIONS_NOT_SUPPORTED, 0, JSEXN_SYNTAXERR, "import assertions are not currently supported")
+MSG_DEF(JSMSG_ILLEGAL_PRIVATE_FIELD,   0, JSEXN_SYNTAXERR, "private fields aren't valid in this context")
+MSG_DEF(JSMSG_ILLEGAL_PRIVATE_NAME,    0, JSEXN_SYNTAXERR, "private names aren't valid in this context")
+MSG_DEF(JSMSG_INVALID_PRIVATE_NAME_PRECEDENCE,    0, JSEXN_SYNTAXERR, "invalid use of private name due to operator precedence")
+MSG_DEF(JSMSG_INVALID_PRIVATE_NAME_IN_UNARY_EXPR,    0, JSEXN_SYNTAXERR, "invalid use of private name in unary expression without object reference")
+MSG_DEF(JSMSG_ILLEGAL_PRIVATE_EXOTIC,  0, JSEXN_TYPEERR, "private fields or private methods aren't allowed on this exotic object")
+MSG_DEF(JSMSG_PRIVATE_FIELD_DOUBLE,    0, JSEXN_TYPEERR, "Initializing an object twice is an error with private fields")
+MSG_DEF(JSMSG_PRIVATE_BRAND_DOUBLE,    0, JSEXN_TYPEERR, "Initializing an object twice is an error with private methods")
+MSG_DEF(JSMSG_CURLY_AFTER_ASSERT,      0, JSEXN_SYNTAXERR, "missing '{' after assert")
+MSG_DEF(JSMSG_DUPLICATE_ASSERT_KEY,    1, JSEXN_SYNTAXERR, "duplicate assert key '{0}'")
+MSG_DEF(JSMSG_COLON_AFTER_ASSERT_KEY,  0, JSEXN_SYNTAXERR, "missing : after assert key")
+MSG_DEF(JSMSG_ASSERT_STRING_LITERAL,   0, JSEXN_SYNTAXERR, "expected string literal")
+MSG_DEF(JSMSG_ASSERT_KEY_EXPECTED,     0, JSEXN_SYNTAXERR, "expected assertion key")
+MSG_DEF(JSMSG_DECORATOR_NAME_EXPECTED, 0, JSEXN_SYNTAXERR, "expected property name in decorator expression")
+MSG_DEF(JSMSG_CLASS_EXPECTED,          0, JSEXN_SYNTAXERR, "expected class")
+
+// UTF-8 source text encoding errors
+MSG_DEF(JSMSG_BAD_LEADING_UTF8_UNIT,   1, JSEXN_SYNTAXERR, "{0} byte doesn't begin a valid UTF-8 code point")
+MSG_DEF(JSMSG_NOT_ENOUGH_CODE_UNITS,   5, JSEXN_SYNTAXERR, "{0} byte in UTF-8 must be followed by {1} byte{2}, but {3} byte{4} present")
+MSG_DEF(JSMSG_BAD_TRAILING_UTF8_UNIT,  1, JSEXN_SYNTAXERR, "bad trailing UTF-8 byte {0} doesn't match the pattern 0b10xxxxxx")
+MSG_DEF(JSMSG_FORBIDDEN_UTF8_CODE_POINT,2,JSEXN_SYNTAXERR, "{0} isn't a valid code point because {1}")
+MSG_DEF(JSMSG_BAD_CODE_UNITS,          1, JSEXN_NOTE, "the code units comprising this invalid code point were: {0}")
+
+// System encoding errors
+MSG_DEF(JSMSG_CANT_CONVERT_TO_NARROW,  0, JSEXN_NOTE, "can't convert to narrow string")
+MSG_DEF(JSMSG_CANT_CONVERT_TO_WIDE,    0, JSEXN_NOTE, "can't convert to wide string")
+MSG_DEF(JSMSG_CANT_CONVERT_WIDE_TO_UTF8, 0, JSEXN_NOTE, "can't convert wide string to UTF-8")
+MSG_DEF(JSMSG_CANT_CONVERT_UTF8_TO_WIDE, 0, JSEXN_NOTE, "can't convert UTF-8 to wide string")
+
+// SmooshMonkey
+MSG_DEF(JSMSG_SMOOSH_COMPILE_ERROR,    1, JSEXN_SYNTAXERR, "{0}")
+MSG_DEF(JSMSG_SMOOSH_UNIMPLEMENTED,    1, JSEXN_INTERNALERR, "{0}")
+
+// asm.js
+MSG_DEF(JSMSG_USE_ASM_TYPE_FAIL,       1, JSEXN_TYPEERR, "asm.js type error: {0}")
+MSG_DEF(JSMSG_USE_ASM_LINK_FAIL,       1, JSEXN_TYPEERR, "asm.js link error: {0}")
+MSG_DEF(JSMSG_USE_ASM_TYPE_OK,         1, JSEXN_WARN,    "Successfully compiled asm.js code (total compilation time {0}ms)")
+MSG_DEF(JSMSG_USE_ASM_TYPE_OK_NO_TIME, 0, JSEXN_WARN,    "Successfully compiled asm.js code ()")
+
+// wasm
+MSG_DEF(JSMSG_WASM_VERBOSE,            1, JSEXN_WARN,    "WebAssembly verbose: {0}")
+MSG_DEF(JSMSG_WASM_COMPILE_WARNING,    1, JSEXN_WARN,    "WebAssembly module validated with warning: {0}")
+MSG_DEF(JSMSG_WASM_HUGE_MEMORY_FAILED, 0, JSEXN_WARN,    "WebAssembly.Memory failed to reserve a large virtual memory region. This may be due to low configured virtual memory limits on this system.")
+MSG_DEF(JSMSG_WASM_COMPILE_ERROR,      1, JSEXN_WASMCOMPILEERROR, "{0}")
+MSG_DEF(JSMSG_WASM_BAD_IMPORT_TYPE,    2, JSEXN_WASMLINKERROR, "import object field '{0}' is not a {1}")
+MSG_DEF(JSMSG_WASM_BAD_IMPORT_SIG,     2, JSEXN_WASMLINKERROR, "imported function '{0}.{1}' signature mismatch")
+MSG_DEF(JSMSG_WASM_BAD_TAG_SIG,        2, JSEXN_WASMLINKERROR, "imported tag '{0}.{1}' signature mismatch")
+MSG_DEF(JSMSG_WASM_BAD_IMP_INDEX,      1, JSEXN_WASMLINKERROR, "imported {0} with incompatible index type")
+MSG_DEF(JSMSG_WASM_BAD_IMP_SIZE,       1, JSEXN_WASMLINKERROR, "imported {0} with incompatible size")
+MSG_DEF(JSMSG_WASM_BAD_IMP_MAX,        1, JSEXN_WASMLINKERROR, "imported {0} with incompatible maximum size")
+MSG_DEF(JSMSG_WASM_IMP_SHARED_REQD,    0, JSEXN_WASMLINKERROR, "imported unshared memory but shared required")
+MSG_DEF(JSMSG_WASM_IMP_SHARED_BANNED,  0, JSEXN_WASMLINKERROR, "imported shared memory but unshared required")
+MSG_DEF(JSMSG_WASM_NO_SHMEM_LINK,      0, JSEXN_WASMLINKERROR, "shared memory is disabled")
+MSG_DEF(JSMSG_WASM_NO_MEM64_LINK,      0, JSEXN_WASMLINKERROR, "memory64 is disabled")
+MSG_DEF(JSMSG_WASM_BAD_GLOB_MUT_LINK,  0, JSEXN_WASMLINKERROR, "imported global mutability mismatch")
+MSG_DEF(JSMSG_WASM_BAD_GLOB_TYPE_LINK, 0, JSEXN_WASMLINKERROR, "imported global type mismatch")
+MSG_DEF(JSMSG_WASM_BAD_TBL_TYPE_LINK,  0, JSEXN_WASMLINKERROR, "imported table type mismatch")
+MSG_DEF(JSMSG_WASM_IND_CALL_TO_NULL,   0, JSEXN_WASMRUNTIMEERROR, "indirect call to null")
+MSG_DEF(JSMSG_WASM_IND_CALL_BAD_SIG,   0, JSEXN_WASMRUNTIMEERROR, "indirect call signature mismatch")
+MSG_DEF(JSMSG_WASM_UNREACHABLE,        0, JSEXN_WASMRUNTIMEERROR, "unreachable executed")
+MSG_DEF(JSMSG_WASM_INTEGER_OVERFLOW,   0, JSEXN_WASMRUNTIMEERROR, "integer overflow")
+MSG_DEF(JSMSG_WASM_INVALID_CONVERSION, 0, JSEXN_WASMRUNTIMEERROR, "invalid conversion to integer")
+MSG_DEF(JSMSG_WASM_INT_DIVIDE_BY_ZERO, 0, JSEXN_WASMRUNTIMEERROR, "integer divide by zero")
+MSG_DEF(JSMSG_WASM_OUT_OF_BOUNDS,      0, JSEXN_WASMRUNTIMEERROR, "index out of bounds")
+MSG_DEF(JSMSG_WASM_UNALIGNED_ACCESS,   0, JSEXN_WASMRUNTIMEERROR, "unaligned memory access")
+MSG_DEF(JSMSG_WASM_WAKE_OVERFLOW,      0, JSEXN_WASMRUNTIMEERROR, "too many woken agents")
+MSG_DEF(JSMSG_WASM_DEREF_NULL,         0, JSEXN_WASMRUNTIMEERROR, "dereferencing null pointer")
+MSG_DEF(JSMSG_WASM_BAD_CAST,           0, JSEXN_WASMRUNTIMEERROR, "bad cast")
+MSG_DEF(JSMSG_WASM_MEM_IMP_LIMIT,      0, JSEXN_WASMRUNTIMEERROR, "too many memory pages")
+MSG_DEF(JSMSG_WASM_TABLE_IMP_LIMIT,    0, JSEXN_WASMRUNTIMEERROR, "too many table elements")
+MSG_DEF(JSMSG_WASM_ARRAY_IMP_LIMIT,    0, JSEXN_WASMRUNTIMEERROR, "too many array elements")
+MSG_DEF(JSMSG_WASM_BAD_RANGE,          2, JSEXN_RANGEERR,    "bad {0} {1}")
+MSG_DEF(JSMSG_WASM_BAD_GROW,           1, JSEXN_RANGEERR,    "failed to grow {0}")
+MSG_DEF(JSMSG_WASM_TABLE_OUT_OF_BOUNDS, 0, JSEXN_WASMRUNTIMEERROR,   "table index out of bounds")
+MSG_DEF(JSMSG_WASM_BAD_ENFORCE_RANGE,  2, JSEXN_TYPEERR,     "bad {0} {1}")
+MSG_DEF(JSMSG_WASM_BAD_BUF_ARG,        0, JSEXN_TYPEERR,     "first argument must be an ArrayBuffer or typed array object")
+MSG_DEF(JSMSG_WASM_BAD_MOD_ARG,        0, JSEXN_TYPEERR,     "first argument must be a WebAssembly.Module")
+MSG_DEF(JSMSG_WASM_BAD_BUF_MOD_ARG,    0, JSEXN_TYPEERR,     "first argument must be a WebAssembly.Module, ArrayBuffer or typed array object")
+MSG_DEF(JSMSG_WASM_BAD_DESC_ARG,       1, JSEXN_TYPEERR,     "first argument must be a {0} descriptor")
+MSG_DEF(JSMSG_WASM_BAD_IMPORT_ARG,     0, JSEXN_TYPEERR,     "second argument must be an object")
+MSG_DEF(JSMSG_WASM_BAD_IMPORT_FIELD,   1, JSEXN_TYPEERR,     "import object field '{0}' is not an Object")
+MSG_DEF(JSMSG_WASM_BAD_REF_NONNULLABLE_VALUE,  0, JSEXN_TYPEERR,     "cannot pass null to non-nullable WebAssembly reference")
+MSG_DEF(JSMSG_WASM_BAD_FUNCREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass WebAssembly exported functions to funcref")
+MSG_DEF(JSMSG_WASM_BAD_ANYREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass a WebAssembly GC object to an anyref")
+MSG_DEF(JSMSG_WASM_BAD_NULL_EXTERNREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass null to nullexternref")
+MSG_DEF(JSMSG_WASM_BAD_NULL_FUNCREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass null to nullfuncref")
+MSG_DEF(JSMSG_WASM_BAD_NULL_ANYREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass null to nullref")
+MSG_DEF(JSMSG_WASM_BAD_EQREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass a WebAssembly GC object to an eqref")
+MSG_DEF(JSMSG_WASM_BAD_STRUCTREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass a WebAssembly struct object to a structref")
+MSG_DEF(JSMSG_WASM_BAD_ARRAYREF_VALUE,  0, JSEXN_TYPEERR,     "can only pass a WebAssembly array object to an arrayref")
+MSG_DEF(JSMSG_WASM_BAD_TYPEREF_VALUE,  0, JSEXN_TYPEERR,     "bad type")
+MSG_DEF(JSMSG_WASM_BAD_VAL_TYPE,       0, JSEXN_TYPEERR,     "cannot pass v128 to or from JS")
+MSG_DEF(JSMSG_WASM_BAD_STRING_VAL_TYPE,    0, JSEXN_TYPEERR,     "bad value type")
+MSG_DEF(JSMSG_WASM_BAD_STRING_IDX_TYPE,    0, JSEXN_TYPEERR,     "bad index type")
+MSG_DEF(JSMSG_WASM_BAD_EXN_ARG,        0, JSEXN_TYPEERR,     "first argument must be a WebAssembly.Tag")
+MSG_DEF(JSMSG_WASM_BAD_EXN_PAYLOAD,    0, JSEXN_TYPEERR,     "second argument must be an object")
+MSG_DEF(JSMSG_WASM_BAD_EXN_PAYLOAD_LEN, 2, JSEXN_TYPEERR,    "expected {0} values but got {1}")
+MSG_DEF(JSMSG_WASM_BAD_EXN_TAG,        0, JSEXN_TYPEERR,     "exception's tag did not match the provided exception tag")
+MSG_DEF(JSMSG_WASM_BAD_EXN_OPTIONS,    0, JSEXN_TYPEERR,     "argument cannot be converted to an ExceptionOptions")
+MSG_DEF(JSMSG_WASM_BAD_FUNCTION_VALUE, 0, JSEXN_TYPEERR,     "second argument must be a function")
+MSG_DEF(JSMSG_WASM_NO_TRANSFER,        0, JSEXN_TYPEERR,     "cannot transfer WebAssembly/asm.js ArrayBuffer")
+MSG_DEF(JSMSG_WASM_TEXT_FAIL,          1, JSEXN_SYNTAXERR,   "wasm text error: {0}")
+MSG_DEF(JSMSG_WASM_MISSING_MAXIMUM,    0, JSEXN_TYPEERR,     "'shared' is true but maximum is not specified")
+MSG_DEF(JSMSG_WASM_GLOBAL_IMMUTABLE,   0, JSEXN_TYPEERR,     "can't set value of immutable global")
+MSG_DEF(JSMSG_WASM_WRONG_NUMBER_OF_VALUES, 2, JSEXN_TYPEERR, "wrong number of values returned by JavaScript to WebAssembly (expected {0}, got {1})")
+MSG_DEF(JSMSG_WASM_NONSHARED_WAIT,     0, JSEXN_WASMRUNTIMEERROR, "atomic wait on non-shared memory")
+MSG_DEF(JSMSG_WASM_SUPPLY_ONLY_ONE,    2, JSEXN_TYPEERR,     "exactly one of {0} and {1} must be supplied")
+MSG_DEF(JSMSG_WASM_MISSING_REQUIRED,   1, JSEXN_TYPEERR,     "Missing required argument {0}")
+
+// Proxy
+MSG_DEF(JSMSG_BAD_GETPROTOTYPEOF_TRAP_RETURN,0,JSEXN_TYPEERR,"proxy getPrototypeOf handler returned a non-object, non-null value")
+MSG_DEF(JSMSG_INCONSISTENT_GETPROTOTYPEOF_TRAP,0,JSEXN_TYPEERR,"proxy getPrototypeOf handler didn't return the target object's prototype")
+MSG_DEF(JSMSG_PROXY_SETPROTOTYPEOF_RETURNED_FALSE, 0, JSEXN_TYPEERR, "proxy setPrototypeOf handler returned false")
+MSG_DEF(JSMSG_INCONSISTENT_SETPROTOTYPEOF_TRAP,0,JSEXN_TYPEERR,"proxy setPrototypeOf handler returned true, even though the target's prototype is immutable because the target is non-extensible")
+MSG_DEF(JSMSG_CANT_CHANGE_EXTENSIBILITY, 0, JSEXN_TYPEERR, "can't change object's extensibility")
+MSG_DEF(JSMSG_CANT_DEFINE_INVALID,     2, JSEXN_TYPEERR, "proxy can't define an incompatible property descriptor ('{0}', {1})")
+MSG_DEF(JSMSG_CANT_DEFINE_NEW,         1, JSEXN_TYPEERR, "proxy can't define a new property '{0}' on a non-extensible object")
+MSG_DEF(JSMSG_CANT_DEFINE_NE_AS_NC,    1, JSEXN_TYPEERR, "proxy can't define a non-existent '{0}' property as non-configurable")
+MSG_DEF(JSMSG_PROXY_DEFINE_RETURNED_FALSE, 1, JSEXN_TYPEERR, "proxy defineProperty handler returned false for property '{0}'")
+MSG_DEF(JSMSG_PROXY_DELETE_RETURNED_FALSE, 1, JSEXN_TYPEERR, "can't delete property '{0}': proxy deleteProperty handler returned false")
+MSG_DEF(JSMSG_PROXY_PREVENTEXTENSIONS_RETURNED_FALSE, 0, JSEXN_TYPEERR, "proxy preventExtensions handler returned false")
+MSG_DEF(JSMSG_PROXY_SET_RETURNED_FALSE, 1, JSEXN_TYPEERR, "proxy set handler returned false for property '{0}'")
+MSG_DEF(JSMSG_CANT_REPORT_AS_NON_EXTENSIBLE, 0, JSEXN_TYPEERR, "proxy can't report an extensible object as non-extensible")
+MSG_DEF(JSMSG_CANT_DELETE_NON_EXTENSIBLE, 1, JSEXN_TYPEERR, "proxy can't delete property '{0}' on a non-extensible object")
+MSG_DEF(JSMSG_CANT_REPORT_C_AS_NC,     1, JSEXN_TYPEERR, "proxy can't report existing configurable property '{0}' as non-configurable")
+MSG_DEF(JSMSG_CANT_REPORT_E_AS_NE,     1, JSEXN_TYPEERR, "proxy can't report an existing own property '{0}' as non-existent on a non-extensible object")
+MSG_DEF(JSMSG_CANT_REPORT_INVALID,     2, JSEXN_TYPEERR, "proxy can't report an incompatible property descriptor ('{0}', {1})")
+MSG_DEF(JSMSG_CANT_REPORT_NC_AS_NE,    1, JSEXN_TYPEERR, "proxy can't report a non-configurable own property '{0}' as non-existent")
+MSG_DEF(JSMSG_CANT_REPORT_NEW,         1, JSEXN_TYPEERR, "proxy can't report a new property '{0}' on a non-extensible object")
+MSG_DEF(JSMSG_CANT_REPORT_NE_AS_NC,    1, JSEXN_TYPEERR, "proxy can't report a non-existent property '{0}' as non-configurable")
+MSG_DEF(JSMSG_CANT_REPORT_W_AS_NW,     1, JSEXN_TYPEERR, "proxy can't report existing writable property '{0}' as non-writable")
+MSG_DEF(JSMSG_CANT_SET_NW_NC,          1, JSEXN_TYPEERR, "proxy can't successfully set a non-writable, non-configurable property '{0}'")
+MSG_DEF(JSMSG_CANT_SET_WO_SETTER,      1, JSEXN_TYPEERR, "proxy can't succesfully set an accessor property '{0}' without a setter")
+MSG_DEF(JSMSG_CANT_SKIP_NC,            1, JSEXN_TYPEERR, "proxy can't skip a non-configurable property '{0}'")
+MSG_DEF(JSMSG_OWNKEYS_STR_SYM,         0, JSEXN_TYPEERR, "proxy [[OwnPropertyKeys]] must return an array with only string and symbol elements")
+MSG_DEF(JSMSG_OWNKEYS_DUPLICATE,       1, JSEXN_TYPEERR, "proxy [[OwnPropertyKeys]] can't report property '{0}' more than once")
+MSG_DEF(JSMSG_MUST_REPORT_SAME_VALUE,  1, JSEXN_TYPEERR, "proxy must report the same value for the non-writable, non-configurable property '{0}'")
+MSG_DEF(JSMSG_MUST_REPORT_UNDEFINED,   1, JSEXN_TYPEERR, "proxy must report undefined for a non-configurable accessor property '{0}' without a getter")
+MSG_DEF(JSMSG_PROXY_CONSTRUCT_OBJECT,  0, JSEXN_TYPEERR, "proxy [[Construct]] must return an object")
+MSG_DEF(JSMSG_PROXY_EXTENSIBILITY,     0, JSEXN_TYPEERR, "proxy must report same extensiblitity as target")
+MSG_DEF(JSMSG_PROXY_GETOWN_OBJORUNDEF, 1, JSEXN_TYPEERR, "proxy [[GetOwnProperty]] must return an object or undefined for property '{0}'")
+MSG_DEF(JSMSG_PROXY_REVOKED,           0, JSEXN_TYPEERR, "illegal operation attempted on a revoked proxy")
+MSG_DEF(JSMSG_BAD_TRAP,                1, JSEXN_TYPEERR, "proxy handler's {0} trap wasn't undefined, null, or callable")
+
+// Structured cloning
+MSG_DEF(JSMSG_SC_BAD_CLONE_VERSION,    0, JSEXN_ERR, "unsupported structured clone version")
+MSG_DEF(JSMSG_SC_BAD_SERIALIZED_DATA,  1, JSEXN_INTERNALERR, "bad serialized structured data ({0})")
+MSG_DEF(JSMSG_SC_DUP_TRANSFERABLE,     0, JSEXN_TYPEERR, "duplicate transferable for structured clone")
+MSG_DEF(JSMSG_SC_NOT_TRANSFERABLE,     0, JSEXN_TYPEERR, "invalid transferable array for structured clone")
+MSG_DEF(JSMSG_SC_UNSUPPORTED_TYPE,     0, JSEXN_TYPEERR, "unsupported type for structured data")
+MSG_DEF(JSMSG_SC_NOT_CLONABLE,         1, JSEXN_TYPEERR, "The {0} object cannot be serialized. The Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy HTTP headers will enable this in the future.")
+MSG_DEF(JSMSG_SC_NOT_CLONABLE_WITH_COOP_COEP, 1, JSEXN_TYPEERR, "The {0} object cannot be serialized. The Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy HTTP headers can be used to enable this.")
+MSG_DEF(JSMSG_SC_SAB_DISABLED,         0, JSEXN_TYPEERR, "SharedArrayBuffer not cloned - shared memory disabled in receiver")
+MSG_DEF(JSMSG_SC_SAB_REFCNT_OFLO,      0, JSEXN_TYPEERR, "SharedArrayBuffer has too many references")
+MSG_DEF(JSMSG_SC_SHMEM_TRANSFERABLE,   0, JSEXN_TYPEERR, "Shared memory objects must not be in the transfer list")
+MSG_DEF(JSMSG_SC_SHMEM_POLICY,         0, JSEXN_TYPEERR, "Policy object must forbid cloning shared memory objects cross-process")
+
+// Debugger
+MSG_DEF(JSMSG_ASSIGN_FUNCTION_OR_NULL, 1, JSEXN_TYPEERR, "value assigned to {0} must be a function or null")
+MSG_DEF(JSMSG_DEBUG_BAD_LINE,          0, JSEXN_TYPEERR, "invalid line number")
+MSG_DEF(JSMSG_DEBUG_BAD_OFFSET,        0, JSEXN_TYPEERR, "invalid script offset")
+MSG_DEF(JSMSG_DEBUG_BREAKPOINT_NOT_ALLOWED, 0, JSEXN_ERR, "breakpoint is not allowed for this opcode")
+MSG_DEF(JSMSG_DEBUG_BAD_REFERENT,      2, JSEXN_TYPEERR, "{0} does not refer to {1}")
+MSG_DEF(JSMSG_DEBUG_BAD_RESUMPTION,    0, JSEXN_TYPEERR, "debugger resumption value must be undefined, {throw: val}, {return: val}, or null")
+MSG_DEF(JSMSG_DEBUG_RESUMPTION_CONFLICT, 0, JSEXN_TYPEERR, "debugger hook returned a resumption, but an earlier hook already did")
+MSG_DEF(JSMSG_DEBUG_CANT_DEBUG_GLOBAL, 0, JSEXN_TYPEERR, "passing non-debuggable global to addDebuggee")
+MSG_DEF(JSMSG_DEBUG_SAME_COMPARTMENT,  0, JSEXN_TYPEERR, "debugger and debuggee must be in different compartments")
+MSG_DEF(JSMSG_DEBUG_CCW_REQUIRED,      1, JSEXN_TYPEERR, "{0}: argument must be an object from a different compartment")
+MSG_DEF(JSMSG_DEBUG_COMPARTMENT_MISMATCH, 2, JSEXN_TYPEERR, "{0}: descriptor .{1} property is an object in a different compartment than the target object")
+MSG_DEF(JSMSG_DEBUG_LOOP,              0, JSEXN_TYPEERR, "cannot debug an object in same compartment as debugger or a compartment that is already debugging the debugger")
+MSG_DEF(JSMSG_DEBUG_NOT_DEBUGGEE,      2, JSEXN_ERR, "{0} is not a debuggee {1}")
+MSG_DEF(JSMSG_DEBUG_NOT_DEBUGGING,     0, JSEXN_ERR, "can't set breakpoint: script global is not a debuggee")
+MSG_DEF(JSMSG_DEBUG_NOT_IDLE,          0, JSEXN_ERR, "can't start debugging: a debuggee script is on the stack")
+MSG_DEF(JSMSG_DEBUG_NOT_ON_STACK,      1, JSEXN_ERR, "{0} is not on stack")
+MSG_DEF(JSMSG_DEBUG_NOT_ON_STACK_OR_SUSPENDED, 1, JSEXN_ERR, "{0} is not on stack or suspended")
+MSG_DEF(JSMSG_DEBUG_NO_ENV_OBJECT,     0, JSEXN_TYPEERR, "declarative Environments don't have binding objects")
+MSG_DEF(JSMSG_DEBUG_PROTO,             2, JSEXN_TYPEERR, "{0}.prototype is not a valid {1} instance")
+MSG_DEF(JSMSG_DEBUG_WRONG_OWNER,       1, JSEXN_TYPEERR, "{0} belongs to a different Debugger")
+MSG_DEF(JSMSG_DEBUG_OPTIMIZED_OUT,     1, JSEXN_ERR, "variable '{0}' has been optimized out")
+MSG_DEF(JSMSG_DEBUG_OPTIMIZED_OUT_FUN, 0, JSEXN_ERR, "function is optimized out")
+MSG_DEF(JSMSG_DEBUG_FORCED_RETURN_DISALLOWED, 0, JSEXN_TYPEERR, "can't force return from a generator before the initial yield")
+MSG_DEF(JSMSG_DEBUG_RESUMPTION_VALUE_DISALLOWED, 0, JSEXN_TYPEERR, "resumption values are disallowed in this hook")
+MSG_DEF(JSMSG_DEBUG_VARIABLE_NOT_FOUND,0, JSEXN_TYPEERR, "variable not found in environment")
+MSG_DEF(JSMSG_DEBUG_WRAPPER_IN_WAY,    3, JSEXN_TYPEERR, "{0} is {1}{2}a global object, but a direct reference is required")
+MSG_DEF(JSMSG_DEBUGGEE_WOULD_RUN,      2, JSEXN_DEBUGGEEWOULDRUN, "debuggee '{0}:{1}' would run")
+MSG_DEF(JSMSG_NOT_CALLABLE_OR_UNDEFINED, 0, JSEXN_TYPEERR, "value is not a function or undefined")
+MSG_DEF(JSMSG_NOT_TRACKING_ALLOCATIONS, 1, JSEXN_ERR, "Cannot call {0} without setting trackingAllocationSites to true")
+MSG_DEF(JSMSG_OBJECT_METADATA_CALLBACK_ALREADY_SET, 0, JSEXN_ERR, "Cannot track object allocation, because other tools are already doing so")
+MSG_DEF(JSMSG_QUERY_INNERMOST_WITHOUT_LINE_URL, 0, JSEXN_TYPEERR, "findScripts query object with 'innermost' property must have 'line' and either 'displayURL', 'url', or 'source'")
+MSG_DEF(JSMSG_QUERY_LINE_WITHOUT_URL, 0, JSEXN_TYPEERR, "findScripts query object has 'line' property, but no 'displayURL', 'url', or 'source' property")
+MSG_DEF(JSMSG_DEBUG_CANT_SET_OPT_ENV, 1, JSEXN_REFERENCEERR, "can't set '{0}' in an optimized-out environment")
+MSG_DEF(JSMSG_DEBUG_INVISIBLE_COMPARTMENT, 0, JSEXN_TYPEERR, "object in compartment marked as invisible to Debugger")
+MSG_DEF(JSMSG_DEBUG_CENSUS_BREAKDOWN,  1, JSEXN_TYPEERR, "unrecognized 'by' value in takeCensus breakdown: {0}")
+MSG_DEF(JSMSG_DEBUG_PROMISE_NOT_RESOLVED, 0, JSEXN_TYPEERR, "Promise hasn't been resolved")
+MSG_DEF(JSMSG_DEBUG_PROMISE_NOT_FULFILLED, 0, JSEXN_TYPEERR, "Promise hasn't been fulfilled")
+MSG_DEF(JSMSG_DEBUG_PROMISE_NOT_REJECTED, 0, JSEXN_TYPEERR, "Promise hasn't been rejected")
+MSG_DEF(JSMSG_DEBUG_NO_BINARY_SOURCE,  0, JSEXN_ERR, "WebAssembly binary source is not available")
+
+// Testing functions
+MSG_DEF(JSMSG_TESTING_SCRIPTS_ONLY, 0, JSEXN_TYPEERR, "only works on scripts")
+MSG_DEF(JSMSG_INVALID_ARGS,         1, JSEXN_ERR, "{0}: invalid arguments")
+
+// Tracelogger
+MSG_DEF(JSMSG_TRACELOGGER_ENABLE_FAIL, 1, JSEXN_ERR, "enabling tracelogger failed: {0}")
+
+// Intl
+MSG_DEF(JSMSG_DATE_NOT_FINITE,         2, JSEXN_RANGEERR, "date value is not finite in {0}.{1}()")
+MSG_DEF(JSMSG_DUPLICATE_VARIANT_SUBTAG, 0, JSEXN_RANGEERR, "duplicate variant subtag")
+MSG_DEF(JSMSG_INTERNAL_INTL_ERROR,     0, JSEXN_ERR, "internal error while computing Intl data")
+MSG_DEF(JSMSG_INVALID_CURRENCY_CODE,   1, JSEXN_RANGEERR, "invalid currency code in NumberFormat(): {0}")
+MSG_DEF(JSMSG_INVALID_UNIT_IDENTIFIER, 1, JSEXN_RANGEERR, "invalid unit identifier in NumberFormat(): {0}")
+MSG_DEF(JSMSG_INVALID_DIGITS_VALUE,    1, JSEXN_RANGEERR, "invalid digits value: {0}")
+MSG_DEF(JSMSG_INVALID_KEY,             1, JSEXN_RANGEERR, "invalid key: {0}")
+MSG_DEF(JSMSG_INVALID_LANGUAGE_TAG,    1, JSEXN_RANGEERR, "invalid language tag: {0}")
+MSG_DEF(JSMSG_INVALID_LOCALES_ELEMENT, 0, JSEXN_TYPEERR, "invalid element in locales argument")
+MSG_DEF(JSMSG_INVALID_LOCALE_MATCHER,  1, JSEXN_RANGEERR, "invalid locale matcher in supportedLocalesOf(): {0}")
+MSG_DEF(JSMSG_INVALID_OPTION_VALUE,    2, JSEXN_RANGEERR, "invalid value {1} for option {0}")
+MSG_DEF(JSMSG_INVALID_TIME_ZONE,       1, JSEXN_RANGEERR, "invalid time zone in DateTimeFormat(): {0}")
+MSG_DEF(JSMSG_INVALID_DATETIME_OPTION, 2, JSEXN_TYPEERR, "can't set option {0} when {1} is used")
+MSG_DEF(JSMSG_INVALID_DATETIME_STYLE,  2, JSEXN_TYPEERR, "can't set option {0} in Date.{1}()")
+MSG_DEF(JSMSG_UNDEFINED_CURRENCY,      0, JSEXN_TYPEERR, "undefined currency in NumberFormat() with currency style")
+MSG_DEF(JSMSG_UNDEFINED_UNIT,          0, JSEXN_TYPEERR, "undefined unit in NumberFormat() with unit style")
+MSG_DEF(JSMSG_UNDEFINED_DATE,          2, JSEXN_TYPEERR, "undefined {0}-date in DateTimeFormat.{1}()")
+MSG_DEF(JSMSG_UNDEFINED_NUMBER,        3, JSEXN_TYPEERR, "undefined {0} number in {1}.{2}()")
+MSG_DEF(JSMSG_UNDEFINED_TYPE,          0, JSEXN_TYPEERR, "missing \"type\" option in DisplayNames()")
+MSG_DEF(JSMSG_EXPONENT_TOO_LARGE,      0, JSEXN_RANGEERR, "exponent is too large")
+MSG_DEF(JSMSG_NAN_NUMBER_RANGE,        3, JSEXN_RANGEERR, "range can't {0} with NaN in {1}.{2}()")
+MSG_DEF(JSMSG_INVALID_NUMBER_OPTION,   2, JSEXN_TYPEERR, "can't set option {0} when {1} is used")
+MSG_DEF(JSMSG_UNEQUAL_FRACTION_DIGITS, 0, JSEXN_RANGEERR, "fraction digits must be the same when roundingIncrement is used")
+
+// RegExp
+MSG_DEF(JSMSG_BAD_CLASS_RANGE,         0, JSEXN_SYNTAXERR, "invalid range in character class")
+MSG_DEF(JSMSG_ESCAPE_AT_END_OF_REGEXP, 0, JSEXN_SYNTAXERR, "\\ at end of pattern")
+MSG_DEF(JSMSG_EXEC_NOT_OBJORNULL,      0, JSEXN_TYPEERR, "RegExp exec method should return object or null")
+MSG_DEF(JSMSG_INVALID_DECIMAL_ESCAPE, 0, JSEXN_SYNTAXERR, "invalid decimal escape in regular expression")
+MSG_DEF(JSMSG_INVALID_GROUP,           0, JSEXN_SYNTAXERR, "invalid regexp group")
+MSG_DEF(JSMSG_INVALID_IDENTITY_ESCAPE, 0, JSEXN_SYNTAXERR, "invalid identity escape in regular expression")
+MSG_DEF(JSMSG_INVALID_UNICODE_ESCAPE,  0, JSEXN_SYNTAXERR, "invalid unicode escape in regular expression")
+MSG_DEF(JSMSG_MISSING_PAREN,           0, JSEXN_SYNTAXERR, "unterminated parenthetical")
+MSG_DEF(JSMSG_NEWREGEXP_FLAGGED,       0, JSEXN_TYPEERR, "can't supply flags when constructing one RegExp from another")
+MSG_DEF(JSMSG_NOTHING_TO_REPEAT,       0, JSEXN_SYNTAXERR, "nothing to repeat")
+MSG_DEF(JSMSG_NUMBERS_OUT_OF_ORDER,    0, JSEXN_SYNTAXERR, "numbers out of order in {} quantifier.")
+MSG_DEF(JSMSG_RANGE_WITH_CLASS_ESCAPE, 0, JSEXN_SYNTAXERR, "character class escape cannot be used in class range in regular expression")
+MSG_DEF(JSMSG_RAW_BRACKET_IN_REGEXP,   0, JSEXN_SYNTAXERR, "raw bracket is not allowed in regular expression with unicode flag")
+MSG_DEF(JSMSG_TOO_MANY_PARENS,         0, JSEXN_INTERNALERR, "too many parentheses in regular expression")
+MSG_DEF(JSMSG_UNICODE_OVERFLOW,        1, JSEXN_SYNTAXERR, "Unicode codepoint must not be greater than 0x10FFFF in {0}")
+MSG_DEF(JSMSG_UNMATCHED_RIGHT_PAREN,   0, JSEXN_SYNTAXERR, "unmatched ) in regular expression")
+MSG_DEF(JSMSG_UNTERM_CLASS,            0, JSEXN_SYNTAXERR, "unterminated character class")
+MSG_DEF(JSMSG_INVALID_PROPERTY_NAME,       0, JSEXN_SYNTAXERR, "invalid property name in regular expression")
+MSG_DEF(JSMSG_INVALID_CLASS_PROPERTY_NAME, 0, JSEXN_SYNTAXERR, "invalid class property name in regular expression")
+MSG_DEF(JSMSG_INCOMPLETE_QUANTIFIER,       0, JSEXN_SYNTAXERR, "incomplete quantifier in regular expression")
+MSG_DEF(JSMSG_INVALID_QUANTIFIER,          0, JSEXN_SYNTAXERR, "invalid quantifier in regular expression")
+MSG_DEF(JSMSG_INVALID_CAPTURE_NAME,        0, JSEXN_SYNTAXERR, "invalid capture group name in regular expression")
+MSG_DEF(JSMSG_DUPLICATE_CAPTURE_NAME,      0, JSEXN_SYNTAXERR, "duplicate capture group name in regular expression")
+MSG_DEF(JSMSG_INVALID_NAMED_REF,           0, JSEXN_SYNTAXERR, "invalid named reference in regular expression")
+MSG_DEF(JSMSG_INVALID_NAMED_CAPTURE_REF,   0, JSEXN_SYNTAXERR, "invalid named capture reference in regular expression")
+MSG_DEF(JSMSG_INCOMPATIBLE_REGEXP_GETTER, 2, JSEXN_TYPEERR, "RegExp.prototype.{0} getter called on non-RegExp object: {1}")
+
+// Self-hosting
+MSG_DEF(JSMSG_DEFAULT_LOCALE_ERROR,    0, JSEXN_ERR, "internal error getting the default locale")
+
+// Typed object
+MSG_DEF(JSMSG_TYPEDOBJECT_SETTING_IMMUTABLE, 0, JSEXN_ERR, "setting immutable field")
+
+// Array
+MSG_DEF(JSMSG_TOO_LONG_ARRAY,         0, JSEXN_TYPEERR, "Too long array")
+
+// Typed array
+MSG_DEF(JSMSG_BAD_INDEX,               0, JSEXN_RANGEERR, "invalid or out-of-range index")
+MSG_DEF(JSMSG_DEFINE_BAD_INDEX,        0, JSEXN_TYPEERR, "can't define element for invalid or out-of-range index")
+MSG_DEF(JSMSG_NON_ARRAY_BUFFER_RETURNED, 0, JSEXN_TYPEERR, "expected ArrayBuffer, but species constructor returned non-ArrayBuffer")
+MSG_DEF(JSMSG_SAME_ARRAY_BUFFER_RETURNED, 0, JSEXN_TYPEERR, "expected different ArrayBuffer, but species constructor returned same ArrayBuffer")
+MSG_DEF(JSMSG_SHORT_ARRAY_BUFFER_RETURNED, 2, JSEXN_TYPEERR, "expected ArrayBuffer with at least {0} bytes, but species constructor returns ArrayBuffer with {1} bytes")
+MSG_DEF(JSMSG_TYPED_ARRAY_BAD_ARGS,    0, JSEXN_TYPEERR, "invalid arguments")
+MSG_DEF(JSMSG_TYPED_ARRAY_DETACHED,    0, JSEXN_TYPEERR, "attempting to access detached ArrayBuffer")
+MSG_DEF(JSMSG_TYPED_ARRAY_CONSTRUCT_OFFSET_BOUNDS, 2, JSEXN_RANGEERR, "start offset of {0}Array should be a multiple of {1}")
+MSG_DEF(JSMSG_TYPED_ARRAY_CONSTRUCT_OFFSET_MISALIGNED, 2, JSEXN_RANGEERR, "buffer length for {0}Array should be a multiple of {1}")
+MSG_DEF(JSMSG_TYPED_ARRAY_CONSTRUCT_OFFSET_LENGTH_BOUNDS, 1, JSEXN_RANGEERR, "size of buffer is too small for {0}Array with byteOffset")
+MSG_DEF(JSMSG_TYPED_ARRAY_CONSTRUCT_ARRAY_LENGTH_BOUNDS, 1, JSEXN_RANGEERR, "attempting to construct out-of-bounds {0}Array on ArrayBuffer")
+MSG_DEF(JSMSG_TYPED_ARRAY_CONSTRUCT_TOO_LARGE, 1, JSEXN_RANGEERR, "{0}Array too large")
+
+MSG_DEF(JSMSG_TYPED_ARRAY_CALL_OR_CONSTRUCT, 1, JSEXN_TYPEERR, "cannot directly {0} builtin %TypedArray%")
+MSG_DEF(JSMSG_NON_TYPED_ARRAY_RETURNED, 0, JSEXN_TYPEERR, "constructor didn't return TypedArray object")
+MSG_DEF(JSMSG_SHORT_TYPED_ARRAY_RETURNED, 2, JSEXN_TYPEERR, "expected TypedArray of at least length {0}, but constructor returned TypedArray of length {1}")
+MSG_DEF(JSMSG_TYPED_ARRAY_NOT_COMPATIBLE, 2, JSEXN_TYPEERR, "{0} elements are incompatible with {1}")
+MSG_DEF(JSMSG_ARRAYBUFFER_REQUIRED, 0, JSEXN_TYPEERR, "ArrayBuffer object required")
+
+MSG_DEF(JSMSG_ARRAYBUFFER_COPY_RANGE, 0, JSEXN_RANGEERR, "ArrayBuffer range incorrect for copying")
+
+// Shared array buffer
+MSG_DEF(JSMSG_SHARED_ARRAY_BAD_LENGTH,  0, JSEXN_RANGEERR, "length argument out of range")
+MSG_DEF(JSMSG_NON_SHARED_ARRAY_BUFFER_RETURNED, 0, JSEXN_TYPEERR, "expected SharedArrayBuffer, but species constructor returned non-SharedArrayBuffer")
+MSG_DEF(JSMSG_SAME_SHARED_ARRAY_BUFFER_RETURNED, 0, JSEXN_TYPEERR, "expected different SharedArrayBuffer, but species constructor returned same SharedArrayBuffer")
+MSG_DEF(JSMSG_SHORT_SHARED_ARRAY_BUFFER_RETURNED, 2, JSEXN_TYPEERR, "expected SharedArrayBuffer with at least {0} bytes, but species constructor returns SharedArrayBuffer with {1} bytes")
+
+// Reflect
+MSG_DEF(JSMSG_BAD_PARSE_NODE,          0, JSEXN_INTERNALERR, "bad parse node")
+
+// Symbol
+MSG_DEF(JSMSG_SYMBOL_TO_STRING,        0, JSEXN_TYPEERR, "can't convert symbol to string")
+MSG_DEF(JSMSG_SYMBOL_TO_NUMBER,        0, JSEXN_TYPEERR, "can't convert symbol to number")
+
+// Atomics and futexes
+MSG_DEF(JSMSG_ATOMICS_BAD_ARRAY,         0, JSEXN_TYPEERR, "invalid array type for the operation")
+MSG_DEF(JSMSG_ATOMICS_WAIT_NOT_ALLOWED,  0, JSEXN_TYPEERR, "waiting is not allowed on this thread")
+
+// XPConnect wrappers and DOM bindings
+MSG_DEF(JSMSG_CANT_SET_INTERPOSED,       1, JSEXN_TYPEERR, "unable to set interposed data property '{0}'")
+MSG_DEF(JSMSG_CANT_DEFINE_WINDOW_ELEMENT, 0, JSEXN_TYPEERR, "can't define elements on a Window object")
+MSG_DEF(JSMSG_CANT_DELETE_WINDOW_ELEMENT, 0, JSEXN_TYPEERR, "can't delete elements from a Window object")
+MSG_DEF(JSMSG_CANT_DEFINE_WINDOW_NAMED_PROPERTY, 1, JSEXN_TYPEERR, "can't define property {0} on window's named properties object")
+MSG_DEF(JSMSG_CANT_DELETE_WINDOW_NAMED_PROPERTY, 1, JSEXN_TYPEERR, "can't delete property {0} from window's named properties object")
+MSG_DEF(JSMSG_CANT_PREVENT_EXTENSIONS,   0, JSEXN_TYPEERR, "can't prevent extensions on this proxy object")
+MSG_DEF(JSMSG_CANT_DEFINE_WINDOW_NC,     0, JSEXN_TYPEERR, "can't define non-configurable property on WindowProxy")
+MSG_DEF(JSMSG_NO_NAMED_SETTER,           2, JSEXN_TYPEERR, "{0} doesn't have a named property setter for '{1}'")
+MSG_DEF(JSMSG_NO_INDEXED_SETTER,         2, JSEXN_TYPEERR, "{0} doesn't have an indexed property setter for '{1}'")
+MSG_DEF(JSMSG_NOT_DATA_DESCRIPTOR,       2, JSEXN_TYPEERR, "can't define a getter/setter for element '{1}' of {0} object")
+
+// Super
+MSG_DEF(JSMSG_CANT_DELETE_SUPER, 0, JSEXN_REFERENCEERR, "invalid delete involving 'super'")
+MSG_DEF(JSMSG_REINIT_THIS,       0, JSEXN_REFERENCEERR, "super() called twice in derived class constructor")
+
+// Modules
+MSG_DEF(JSMSG_MISSING_INDIRECT_EXPORT,      0, JSEXN_SYNTAXERR, "indirect export not found")
+MSG_DEF(JSMSG_AMBIGUOUS_INDIRECT_EXPORT,    0, JSEXN_SYNTAXERR, "ambiguous indirect export")
+MSG_DEF(JSMSG_MISSING_IMPORT,               0, JSEXN_SYNTAXERR, "import not found")
+MSG_DEF(JSMSG_AMBIGUOUS_IMPORT,             0, JSEXN_SYNTAXERR, "ambiguous import")
+MSG_DEF(JSMSG_MISSING_EXPORT,               1, JSEXN_SYNTAXERR, "local binding for export '{0}' not found")
+MSG_DEF(JSMSG_BAD_MODULE_STATUS,            1, JSEXN_INTERNALERR, "module record has unexpected status: {0}")
+MSG_DEF(JSMSG_DYNAMIC_IMPORT_FAILED,        1, JSEXN_TYPEERR, "error loading dynamically imported module: {0}")
+MSG_DEF(JSMSG_DYNAMIC_IMPORT_NOT_SUPPORTED, 0, JSEXN_TYPEERR, "Dynamic import not supported in this context")
+
+// Import maps
+MSG_DEF(JSMSG_IMPORT_MAPS_PARSE_FAILED, 1, JSEXN_SYNTAXERR, "Failed to parse import map: Invalid JSON format. {0}")
+MSG_DEF(JSMSG_IMPORT_MAPS_NOT_A_MAP, 0, JSEXN_TYPEERR, "the top-level value needs to be a JSON object")
+MSG_DEF(JSMSG_IMPORT_MAPS_IMPORTS_NOT_A_MAP, 0, JSEXN_TYPEERR, "the imports top-level key needs to be a JSON object")
+MSG_DEF(JSMSG_IMPORT_MAPS_SCOPES_NOT_A_MAP, 0, JSEXN_TYPEERR, "the scopes top-level key needs to be a JSON object")
+MSG_DEF(JSMSG_IMPORT_MAPS_SCOPE_VALUE_NOT_A_MAP, 1, JSEXN_TYPEERR, "the value of the scope with prefix '{0}' needs to be a JSON object")
+
+// Promise
+MSG_DEF(JSMSG_CANNOT_RESOLVE_PROMISE_WITH_ITSELF,       0, JSEXN_TYPEERR, "A promise cannot be resolved with itself.")
+MSG_DEF(JSMSG_PROMISE_CAPABILITY_HAS_SOMETHING_ALREADY, 0, JSEXN_TYPEERR, "GetCapabilitiesExecutor function already invoked with non-undefined values.")
+MSG_DEF(JSMSG_PROMISE_RESOLVE_FUNCTION_NOT_CALLABLE,    0, JSEXN_TYPEERR, "A Promise subclass passed a non-callable value as the resolve function.")
+MSG_DEF(JSMSG_PROMISE_REJECT_FUNCTION_NOT_CALLABLE,     0, JSEXN_TYPEERR, "A Promise subclass passed a non-callable value as the reject function.")
+MSG_DEF(JSMSG_PROMISE_ERROR_IN_WRAPPED_REJECTION_REASON,0, JSEXN_INTERNALERR, "Promise rejection value is a non-unwrappable cross-compartment wrapper.")
+MSG_DEF(JSMSG_PROMISE_ANY_REJECTION, 0, JSEXN_AGGREGATEERR, "No Promise in Promise.any was resolved")
+
+// Iterator
+MSG_DEF(JSMSG_RETURN_NOT_CALLABLE,     0, JSEXN_TYPEERR, "property 'return' of iterator is not callable")
+MSG_DEF(JSMSG_ITERATOR_NO_THROW,       0, JSEXN_TYPEERR, "iterator does not have a 'throw' method")
+
+// Async Function
+MSG_DEF(JSMSG_UNHANDLABLE_PROMISE_REJECTION_WARNING, 0, JSEXN_WARN, "unhandlable error after resolving async function's promise")
+
+// Async Iteration
+MSG_DEF(JSMSG_FOR_AWAIT_NOT_OF,        0, JSEXN_SYNTAXERR, "'for await' loop should be used with 'of'")
+MSG_DEF(JSMSG_NOT_AN_ASYNC_GENERATOR,  0, JSEXN_TYPEERR, "Not an async generator")
+MSG_DEF(JSMSG_NOT_AN_ASYNC_ITERATOR,   0, JSEXN_TYPEERR, "Not an async from sync iterator")
+MSG_DEF(JSMSG_GET_ASYNC_ITER_RETURNED_PRIMITIVE, 0, JSEXN_TYPEERR, "[Symbol.asyncIterator]() returned a non-object value")
+MSG_DEF(JSMSG_SUSPENDED_QUEUE_NOT_EMPTY, 0, JSEXN_INTERNALERR, "Async generator is in invalid state due to debugger interaction")
+
+// ReadableStream
+MSG_DEF(JSMSG_READABLESTREAM_UNDERLYINGSOURCE_TYPE_WRONG,0, JSEXN_RANGEERR,"'underlyingSource.type' must be \"bytes\" or undefined.")
+MSG_DEF(JSMSG_READABLESTREAM_BYTES_TYPE_NOT_IMPLEMENTED, 0, JSEXN_RANGEERR,"support for 'new ReadableStream({ type: \"bytes\" })' is not yet implemented")
+MSG_DEF(JSMSG_READABLESTREAM_BYOB_READER_FOR_NON_BYTE_STREAM,0,JSEXN_TYPEERR,"can't get a BYOB reader for a non-byte stream")
+MSG_DEF(JSMSG_READABLESTREAM_INVALID_READER_MODE,        0, JSEXN_TYPEERR,"'mode' must be \"byob\" or undefined.")
+MSG_DEF(JSMSG_NUMBER_MUST_BE_FINITE_NON_NEGATIVE, 1, JSEXN_RANGEERR, "'{0}' must be a finite, non-negative number.")
+MSG_DEF(JSMSG_READABLESTREAM_LOCKED_METHOD,              1, JSEXN_TYPEERR, "'{0}' can't be called on a locked stream.")
+MSG_DEF(JSMSG_READABLESTREAM_LOCKED,                     0, JSEXN_TYPEERR, "A Reader may only be created for an unlocked ReadableStream.")
+MSG_DEF(JSMSG_READABLESTREAM_NOT_DEFAULT_CONTROLLER,     1, JSEXN_TYPEERR, "{0} requires a ReadableStreamDefaultController.")
+MSG_DEF(JSMSG_READABLESTREAMREADER_NOT_OWNED,            1, JSEXN_TYPEERR, "The ReadableStream reader method '{0}' may only be called on a reader owned by a stream.")
+MSG_DEF(JSMSG_READABLESTREAMREADER_NOT_EMPTY,            1, JSEXN_TYPEERR, "The ReadableStream reader method '{0}' may not be called on a reader with read requests.")
+MSG_DEF(JSMSG_READABLESTREAMREADER_RELEASED,             0, JSEXN_TYPEERR, "The ReadableStream reader was released.")
+MSG_DEF(JSMSG_READABLESTREAMCONTROLLER_CLOSED,           1, JSEXN_TYPEERR, "'{0}' called on a stream already closing.")
+MSG_DEF(JSMSG_READABLESTREAMCONTROLLER_NOT_READABLE,     1, JSEXN_TYPEERR, "'{0}' may only be called on a stream in the 'readable' state.")
+MSG_DEF(JSMSG_READABLEBYTESTREAMCONTROLLER_BAD_CHUNKSIZE,0, JSEXN_RANGEERR, "ReadableByteStreamController requires a positive integer or undefined for 'autoAllocateChunkSize'.")
+MSG_DEF(JSMSG_READABLEBYTESTREAMCONTROLLER_BAD_CHUNK,    1, JSEXN_TYPEERR, "{0} passed a bad chunk.")
+MSG_DEF(JSMSG_READABLEBYTESTREAMCONTROLLER_CLOSE_PENDING_PULL, 0, JSEXN_TYPEERR, "The ReadableByteStreamController cannot be closed while the buffer is being filled.")
+
+// Other Stream-related
+MSG_DEF(JSMSG_STREAM_MISSING_HIGHWATERMARK,              0, JSEXN_TYPEERR,  "'highWaterMark' must not be undefined.")
+MSG_DEF(JSMSG_STREAM_INVALID_HIGHWATERMARK,              0, JSEXN_RANGEERR, "'highWaterMark' must be a non-negative, non-NaN number.")
+MSG_DEF(JSMSG_STREAM_CONSUME_ERROR,                      0, JSEXN_TYPEERR,  "error consuming stream body")
+
+// (wasm) Response-related
+MSG_DEF(JSMSG_WASM_ERROR_CONSUMING_RESPONSE,             0, JSEXN_TYPEERR,  "WebAssembly: There was an error consuming the Response")
+MSG_DEF(JSMSG_WASM_BAD_RESPONSE_VALUE,                   0, JSEXN_TYPEERR,  "WebAssembly: Expected Response or Promise resolving to Response")
+MSG_DEF(JSMSG_WASM_BAD_RESPONSE_MIME_TYPE,               2, JSEXN_TYPEERR,  "WebAssembly: Response has unsupported MIME type '{0}' expected '{1}'")
+MSG_DEF(JSMSG_WASM_BAD_RESPONSE_CORS_SAME_ORIGIN,        0, JSEXN_TYPEERR,  "WebAssembly: Response.type must be 'basic', 'cors' or 'default'")
+MSG_DEF(JSMSG_WASM_BAD_RESPONSE_STATUS,                  0, JSEXN_TYPEERR,  "WebAssembly: Response does not have ok status")
+MSG_DEF(JSMSG_WASM_RESPONSE_ALREADY_CONSUMED,            0, JSEXN_TYPEERR,  "WebAssembly: Response already consumed")
+
+// BigInt
+MSG_DEF(JSMSG_BIGINT_TO_NUMBER, 0, JSEXN_TYPEERR, "can't convert BigInt to number")
+MSG_DEF(JSMSG_NONINTEGER_NUMBER_TO_BIGINT, 1, JSEXN_RANGEERR, "{0} can't be converted to BigInt because it isn't an integer")
+MSG_DEF(JSMSG_BIGINT_TOO_LARGE, 0, JSEXN_RANGEERR, "BigInt is too large to allocate")
+MSG_DEF(JSMSG_BIGINT_DIVISION_BY_ZERO, 0, JSEXN_RANGEERR, "BigInt division by zero")
+MSG_DEF(JSMSG_BIGINT_NEGATIVE_EXPONENT, 0, JSEXN_RANGEERR, "BigInt negative exponent")
+MSG_DEF(JSMSG_BIGINT_INVALID_SYNTAX, 0, JSEXN_SYNTAXERR, "invalid BigInt syntax")
+MSG_DEF(JSMSG_BIGINT_NOT_SERIALIZABLE, 0, JSEXN_TYPEERR, "BigInt value can't be serialized in JSON")
+
+// FinalizationRegistry
+MSG_DEF(JSMSG_NOT_A_FINALIZATION_REGISTRY,               1, JSEXN_TYPEERR, "{0} is not a FinalizationRegistry")
+MSG_DEF(JSMSG_BAD_HELD_VALUE,                            0, JSEXN_TYPEERR, "The heldValue parameter passed to FinalizationRegistry.register must not be the same as the target parameter")
+MSG_DEF(JSMSG_BAD_UNREGISTER_TOKEN,                      1, JSEXN_TYPEERR, "Invalid unregister token passed to {0}")
+MSG_DEF(JSMSG_BAD_FINALIZATION_REGISTRY_OBJECT,          0, JSEXN_TYPEERR, "cannot register the given object with a FinalizationRegistry")
+
+// WeakRef
+MSG_DEF(JSMSG_NOT_A_WEAK_REF,                            1, JSEXN_TYPEERR, "{0} is not a WeakRef")
+MSG_DEF(JSMSG_BAD_WEAKREF_TARGET,                        0, JSEXN_TYPEERR, "cannot use the given object as the target of a WeakRef")
+
+// Iterator Helpers
+MSG_DEF(JSMSG_NEGATIVE_LIMIT,                            0, JSEXN_RANGEERR, "Iterator limits cannot be negative")
+
+// Record and Tuple
+MSG_DEF(JSMSG_RECORD_TUPLE_NO_OBJECT,                    0, JSEXN_TYPEERR, "Record and Tuple can only contain primitive values")
+MSG_DEF(JSMSG_RECORD_NO_PROTO,                           0, JSEXN_SYNTAXERR, "__proto__ is not a valid literal key in records")
+MSG_DEF(JSMSG_RECORD_NO_SYMBOL_KEY,                      0, JSEXN_TYPEERR, "Symbols cannot be used as record keys")
+MSG_DEF(JSMSG_BAD_TUPLE_INDEX,        0, JSEXN_RANGEERR, "index out of range for tuple")
+MSG_DEF(JSMSG_BAD_TUPLE_OBJECT, 0, JSEXN_TYPEERR, "value of TupleObject must be a Tuple")
+MSG_DEF(JSMSG_RECORD_TUPLE_TO_NUMBER,        0, JSEXN_TYPEERR, "can't convert Record or Tuple to number")
+
+
+// Shadow Realms
+MSG_DEF(JSMSG_NOT_SHADOW_REALM,                    0, JSEXN_TYPEERR, "Object is not a ShadowRealm")
+MSG_DEF(JSMSG_SHADOW_REALM_EVALUATE_NOT_STRING,    0, JSEXN_TYPEERR, "a ShadowRealm can only evaluate a string")
+MSG_DEF(JSMSG_SHADOW_REALM_INVALID_RETURN,    0, JSEXN_TYPEERR, "return value not primitive or callable")
+MSG_DEF(JSMSG_SHADOW_REALM_WRAP_FAILURE,    0, JSEXN_TYPEERR, "unable to wrap callable return object")
+MSG_DEF(JSMSG_SHADOW_REALM_EVALUATE_FAILURE,    0, JSEXN_TYPEERR, "evaluate failed.")
+MSG_DEF(JSMSG_SHADOW_REALM_EVALUATE_FAILURE_DETAIL,    1, JSEXN_TYPEERR, "evaluate failed, error was {0}")
+MSG_DEF(JSMSG_SHADOW_REALM_WRAPPED_EXECUTION_FAILURE,    0, JSEXN_TYPEERR, "wrapped function threw.")
+MSG_DEF(JSMSG_SHADOW_REALM_WRAPPED_EXECUTION_FAILURE_DETAIL,    1, JSEXN_TYPEERR, "wrapped function threw, error was {0}")
+
+MSG_DEF(JSMSG_SHADOW_REALM_EXPORT_NOT_STRING,    0, JSEXN_TYPEERR, "exportName must be a string")
+MSG_DEF(JSMSG_SHADOW_REALM_IMPORTVALUE_FAILED,    0, JSEXN_TYPEERR, "import value failed")
+MSG_DEF(JSMSG_SHADOW_REALM_VALUE_NOT_EXPORTED,    0, JSEXN_TYPEERR, "value not exported")
+
+// Decorators
+MSG_DEF(JSMSG_DECORATOR_INVALID_RETURN_TYPE, 0, JSEXN_TYPEERR, "Invalid value returned from decorator: decorators can only return undefined or a callable")
+
+//clang-format on
diff --git a/js/public/friend/JSMEnvironment.h b/js/public/friend/JSMEnvironment.h
new file mode 100644
index 0000000000..ad16f2ba62
--- /dev/null
+++ b/js/public/friend/JSMEnvironment.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Functionality provided for the JSM component loader in Gecko, that requires
+ * its own unique manner of global environment and currently requires assistance
+ * from SpiderMonkey to do so.
+ *
+ * Embedders who aren't Gecko can ignore this header.
+ */
+
+#ifndef js_friend_JSMEnvironment_h
+#define js_friend_JSMEnvironment_h
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/GCVector.h"  // JS::StackGCVector
+#include "js/TypeDecls.h"
+
+// A 'JSMEnvironment' refers to an environment chain constructed for JSM loading
+// in a shared global. Internally it is a NonSyntacticVariablesObject with a
+// corresponding extensible LexicalEnvironmentObject that is accessible by
+// JS_ExtensibleLexicalEnvironment. The |this| value of that lexical environment
+// is the NSVO itself.
+//
+// Normal global environment (ES6):     JSM "global" environment:
+//
+//                                      * - extensible lexical environment
+//                                      |   (code runs in this environment;
+//                                      |    `let/const` bindings go here)
+//                                      |
+//                                      * - JSMEnvironment (=== `this`)
+//                                      |   (`var` bindings go here)
+//                                      |
+// * - extensible lexical environment   * - extensible lexical environment
+// |   (code runs in this environment;  |   (empty)
+// |    `let/const` bindings go here)   |
+// |                                    |
+// * - actual global (=== `this`)       * - shared JSM global
+//     (var bindings go here; and           (Object, Math, etc. live here)
+//      Object, Math, etc. live here)
+
+namespace JS {
+
+/**
+ * Allocate a new environment in the current compartment that is compatible with
+ * JSM shared loading.
+ */
+extern JS_PUBLIC_API JSObject* NewJSMEnvironment(JSContext* cx);
+
+/**
+ * Execute the given script (copied into the current compartment if necessary)
+ * in the given JSMEnvironment.  The script must have been compiled for
+ * hasNonSyntacticScope.  The |jsmEnv| must have been previously allocated by
+ * |NewJSMEnvironment|.
+ *
+ * NOTE: The associated extensible lexical environment is reused.
+ */
+extern JS_PUBLIC_API bool ExecuteInJSMEnvironment(JSContext* cx,
+                                                  Handle<JSScript*> script,
+                                                  Handle<JSObject*> jsmEnv);
+
+// Additionally, target objects may be specified as required by the Gecko
+// subscript loader. These are wrapped in non-syntactic WithEnvironments and
+// temporarily placed on the environment chain.
+extern JS_PUBLIC_API bool ExecuteInJSMEnvironment(
+    JSContext* cx, Handle<JSScript*> script, Handle<JSObject*> jsmEnv,
+    Handle<StackGCVector<JSObject*>> targetObj);
+
+// Used by native methods to determine the JSMEnvironment of caller if possible
+// by looking at stack frames. Returns nullptr if top frame isn't a scripted
+// caller in a JSM.
+//
+// NOTE: This may find NonSyntacticVariablesObject generated by other embedding
+// such as a Gecko FrameScript. Caller can check the compartment if needed.
+extern JS_PUBLIC_API JSObject* GetJSMEnvironmentOfScriptedCaller(JSContext* cx);
+
+/**
+ * Determine if obj is a JSMEnvironment
+ *
+ * NOTE: This may return true for an NonSyntacticVariablesObject generated by
+ * other embedding such as a Gecko FrameScript. Caller can check compartment.
+ */
+extern JS_PUBLIC_API bool IsJSMEnvironment(JSObject* obj);
+
+}  // namespace JS
+
+#endif  // js_friend_JSMEnvironment_h
diff --git a/js/public/friend/PerformanceHint.h b/js/public/friend/PerformanceHint.h
new file mode 100644
index 0000000000..ca743e3ab7
--- /dev/null
+++ b/js/public/friend/PerformanceHint.h
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef js_friend_PerformanceHint_h
+#define js_friend_PerformanceHint_h
+
+#include "jstypes.h"       // JS_PUBLIC_API
+#include "js/TypeDecls.h"  // JSContext
+
+namespace js {
+namespace gc {
+
+// API to let the DOM tell us whether we're currently in pageload.
+//
+// This currently affects nursery sizing; we tolerate large nursery sizes (and
+// hence longer minor GC pauses) during pageload so as not to limit performance.
+
+enum class PerformanceHint { Normal, InPageLoad };
+
+extern JS_PUBLIC_API void SetPerformanceHint(JSContext* cx,
+                                             PerformanceHint hint);
+
+} /* namespace gc */
+} /* namespace js */
+
+#endif  // js_friend_PerformanceHint_h
diff --git a/js/public/friend/StackLimits.h b/js/public/friend/StackLimits.h
new file mode 100644
index 0000000000..061c0efcf0
--- /dev/null
+++ b/js/public/friend/StackLimits.h
@@ -0,0 +1,323 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef js_friend_StackLimits_h
+#define js_friend_StackLimits_h
+
+#include "mozilla/Attributes.h"  // MOZ_ALWAYS_INLINE, MOZ_COLD
+#include "mozilla/Likely.h"      // MOZ_LIKELY
+#include "mozilla/Variant.h"     // mozilla::Variant, mozilla::AsVariant
+
+#include <stddef.h>  // size_t
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/HeapAPI.h"  // JS::StackKind, JS::StackForTrustedScript, JS::StackForUntrustedScript
+#include "js/RootingAPI.h"  // JS::RootingContext
+#include "js/Stack.h"       // JS::NativeStackLimit
+#include "js/Utility.h"     // JS_STACK_OOM_POSSIBLY_FAIL
+
+struct JS_PUBLIC_API JSContext;
+
+#ifndef JS_STACK_GROWTH_DIRECTION
+#  ifdef __hppa
+#    define JS_STACK_GROWTH_DIRECTION (1)
+#  else
+#    define JS_STACK_GROWTH_DIRECTION (-1)
+#  endif
+#endif
+
+namespace js {
+
+class FrontendContext;
+
+#ifdef __wasi__
+extern MOZ_COLD JS_PUBLIC_API void IncWasiRecursionDepth(JSContext* cx);
+extern MOZ_COLD JS_PUBLIC_API void DecWasiRecursionDepth(JSContext* cx);
+extern MOZ_COLD JS_PUBLIC_API bool CheckWasiRecursionLimit(JSContext* cx);
+
+extern MOZ_COLD JS_PUBLIC_API void IncWasiRecursionDepth(FrontendContext* fc);
+extern MOZ_COLD JS_PUBLIC_API void DecWasiRecursionDepth(FrontendContext* fc);
+extern MOZ_COLD JS_PUBLIC_API bool CheckWasiRecursionLimit(FrontendContext* fc);
+#endif  // __wasi__
+
+// AutoCheckRecursionLimit can be used to check whether we're close to using up
+// the C++ stack.
+//
+// Typical usage is like this:
+//
+//   AutoCheckRecursionLimit recursion(cx);
+//   if (!recursion.check(cx)) {
+//     return false;
+//   }
+//
+// The check* functions return |false| if we are close to the stack limit.
+// They also report an overrecursion error, except for the DontReport variants.
+//
+// The checkSystem variant gives us a little extra space so we can ensure that
+// crucial code is able to run.
+//
+// checkConservative allows less space than any other check, including a safety
+// buffer (as in, it uses the untrusted limit and subtracts a little more from
+// it).
+class MOZ_RAII AutoCheckRecursionLimit {
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkLimitImpl(
+      JS::NativeStackLimit limit, void* sp) const;
+
+  MOZ_ALWAYS_INLINE JS::NativeStackLimit getStackLimitSlow(JSContext* cx) const;
+  MOZ_ALWAYS_INLINE JS::NativeStackLimit getStackLimitHelper(
+      JSContext* cx, JS::StackKind kind, int extraAllowance) const;
+
+  JS::NativeStackLimit getStackLimit(FrontendContext* fc) const;
+
+  JS_PUBLIC_API JS::StackKind stackKindForCurrentPrincipal(JSContext* cx) const;
+
+  JS_PUBLIC_API void assertMainThread(JSContext* cx) const;
+
+#ifdef __wasi__
+  // The JSContext outlives AutoCheckRecursionLimit so it is safe to use raw
+  // pointer here.
+  mozilla::Variant<JSContext*, FrontendContext*> context_;
+#endif  // __wasi__
+
+ public:
+  explicit MOZ_ALWAYS_INLINE AutoCheckRecursionLimit(JSContext* cx)
+#ifdef __wasi__
+      : context_(mozilla::AsVariant(cx))
+#endif  // __wasi__
+  {
+#ifdef __wasi__
+    incWasiRecursionDepth();
+#endif  // __wasi__
+  }
+
+  explicit MOZ_ALWAYS_INLINE AutoCheckRecursionLimit(FrontendContext* fc)
+#ifdef __wasi__
+      : context_(mozilla::AsVariant(fc))
+#endif  // __wasi__
+  {
+#ifdef __wasi__
+    incWasiRecursionDepth();
+#endif  // __wasi__
+  }
+
+  MOZ_ALWAYS_INLINE ~AutoCheckRecursionLimit() {
+#ifdef __wasi__
+    decWasiRecursionDepth();
+#endif  // __wasi__
+  }
+
+#ifdef __wasi__
+  MOZ_ALWAYS_INLINE void incWasiRecursionDepth() {
+    if (context_.is<JSContext*>()) {
+      JSContext* cx = context_.as<JSContext*>();
+      IncWasiRecursionDepth(cx);
+    } else {
+      FrontendContext* fc = context_.as<FrontendContext*>();
+      IncWasiRecursionDepth(fc);
+    }
+  }
+
+  MOZ_ALWAYS_INLINE void decWasiRecursionDepth() {
+    if (context_.is<JSContext*>()) {
+      JSContext* cx = context_.as<JSContext*>();
+      DecWasiRecursionDepth(cx);
+    } else {
+      FrontendContext* fc = context_.as<FrontendContext*>();
+      DecWasiRecursionDepth(fc);
+    }
+  }
+
+  MOZ_ALWAYS_INLINE bool checkWasiRecursionLimit() const {
+    if (context_.is<JSContext*>()) {
+      JSContext* cx = context_.as<JSContext*>();
+      if (!CheckWasiRecursionLimit(cx)) {
+        return false;
+      }
+    } else {
+      FrontendContext* fc = context_.as<FrontendContext*>();
+      if (!CheckWasiRecursionLimit(fc)) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+#endif  // __wasi__
+
+  AutoCheckRecursionLimit(const AutoCheckRecursionLimit&) = delete;
+  void operator=(const AutoCheckRecursionLimit&) = delete;
+
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool check(JSContext* cx) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool check(FrontendContext* fc) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkDontReport(JSContext* cx) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkDontReport(
+      FrontendContext* fc) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkWithExtra(JSContext* cx,
+                                                      size_t extra) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkWithStackPointerDontReport(
+      JSContext* cx, void* sp) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkWithStackPointerDontReport(
+      FrontendContext* fc, void* sp) const;
+
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkConservative(JSContext* cx) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkConservativeDontReport(
+      JSContext* cx) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkConservativeDontReport(
+      JS::NativeStackLimit limit) const;
+
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkSystem(JSContext* cx) const;
+  [[nodiscard]] MOZ_ALWAYS_INLINE bool checkSystemDontReport(
+      JSContext* cx) const;
+};
+
+extern MOZ_COLD JS_PUBLIC_API void ReportOverRecursed(JSContext* maybecx);
+extern MOZ_COLD JS_PUBLIC_API void ReportOverRecursed(FrontendContext* fc);
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkLimitImpl(
+    JS::NativeStackLimit limit, void* sp) const {
+  JS_STACK_OOM_POSSIBLY_FAIL();
+
+#ifdef __wasi__
+  if (!checkWasiRecursionLimit()) {
+    return false;
+  }
+#endif  // __wasi__
+
+#if JS_STACK_GROWTH_DIRECTION > 0
+  return MOZ_LIKELY(JS::NativeStackLimit(sp) < limit);
+#else
+  return MOZ_LIKELY(JS::NativeStackLimit(sp) > limit);
+#endif
+}
+
+MOZ_ALWAYS_INLINE JS::NativeStackLimit
+AutoCheckRecursionLimit::getStackLimitSlow(JSContext* cx) const {
+  JS::StackKind kind = stackKindForCurrentPrincipal(cx);
+  return getStackLimitHelper(cx, kind, 0);
+}
+
+MOZ_ALWAYS_INLINE JS::NativeStackLimit
+AutoCheckRecursionLimit::getStackLimitHelper(JSContext* cx, JS::StackKind kind,
+                                             int extraAllowance) const {
+  assertMainThread(cx);
+  JS::NativeStackLimit limit =
+      JS::RootingContext::get(cx)->nativeStackLimit[kind];
+#if JS_STACK_GROWTH_DIRECTION > 0
+  limit += extraAllowance;
+#else
+  limit -= extraAllowance;
+#endif
+  return limit;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::check(JSContext* cx) const {
+  if (MOZ_UNLIKELY(!checkDontReport(cx))) {
+    ReportOverRecursed(cx);
+    return false;
+  }
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::check(
+    FrontendContext* fc) const {
+  if (MOZ_UNLIKELY(!checkDontReport(fc))) {
+    ReportOverRecursed(fc);
+    return false;
+  }
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkDontReport(
+    JSContext* cx) const {
+  int stackDummy;
+  return checkWithStackPointerDontReport(cx, &stackDummy);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkDontReport(
+    FrontendContext* fc) const {
+  int stackDummy;
+  return checkWithStackPointerDontReport(fc, &stackDummy);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkWithStackPointerDontReport(
+    JSContext* cx, void* sp) const {
+  // getStackLimitSlow(cx) is pretty slow because it has to do an uninlined
+  // call to stackKindForCurrentPrincipal to determine which stack limit to
+  // use. To work around this, check the untrusted limit first to avoid the
+  // overhead in most cases.
+  JS::NativeStackLimit untrustedLimit =
+      getStackLimitHelper(cx, JS::StackForUntrustedScript, 0);
+  if (MOZ_LIKELY(checkLimitImpl(untrustedLimit, sp))) {
+    return true;
+  }
+  return checkLimitImpl(getStackLimitSlow(cx), sp);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkWithStackPointerDontReport(
+    FrontendContext* fc, void* sp) const {
+  return checkLimitImpl(getStackLimit(fc), sp);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkWithExtra(
+    JSContext* cx, size_t extra) const {
+  char stackDummy;
+  char* sp = &stackDummy;
+#if JS_STACK_GROWTH_DIRECTION > 0
+  sp += extra;
+#else
+  sp -= extra;
+#endif
+  if (MOZ_UNLIKELY(!checkWithStackPointerDontReport(cx, sp))) {
+    ReportOverRecursed(cx);
+    return false;
+  }
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkSystem(
+    JSContext* cx) const {
+  if (MOZ_UNLIKELY(!checkSystemDontReport(cx))) {
+    ReportOverRecursed(cx);
+    return false;
+  }
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkSystemDontReport(
+    JSContext* cx) const {
+  JS::NativeStackLimit limit =
+      getStackLimitHelper(cx, JS::StackForSystemCode, 0);
+  int stackDummy;
+  return checkLimitImpl(limit, &stackDummy);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkConservative(
+    JSContext* cx) const {
+  if (MOZ_UNLIKELY(!checkConservativeDontReport(cx))) {
+    ReportOverRecursed(cx);
+    return false;
+  }
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkConservativeDontReport(
+    JSContext* cx) const {
+  JS::NativeStackLimit limit = getStackLimitHelper(
+      cx, JS::StackForUntrustedScript, -4096 * int(sizeof(size_t)));
+  int stackDummy;
+  return checkLimitImpl(limit, &stackDummy);
+}
+
+MOZ_ALWAYS_INLINE bool AutoCheckRecursionLimit::checkConservativeDontReport(
+    JS::NativeStackLimit limit) const {
+  int stackDummy;
+  return checkLimitImpl(limit, &stackDummy);
+}
+
+}  // namespace js
+
+#endif  // js_friend_StackLimits_h
diff --git a/js/public/friend/UsageStatistics.h b/js/public/friend/UsageStatistics.h
new file mode 100644
index 0000000000..0c23b0128f
--- /dev/null
+++ b/js/public/friend/UsageStatistics.h
@@ -0,0 +1,100 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Telemetry and use counter functionality. */
+
+#ifndef js_friend_UsageStatistics_h
+#define js_friend_UsageStatistics_h
+
+#include <stdint.h>  // uint32_t
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+
+/*
+ * Telemetry reasons passed to the accumulate telemetry callback.
+ *
+ * It's OK for these enum values to change as they will be mapped to a fixed
+ * member of the mozilla::Telemetry::HistogramID enum by the callback.
+ */
+#define FOR_EACH_JS_METRIC(_)                   \
+  _(GC_REASON_2, Enumeration)                   \
+  _(GC_IS_COMPARTMENTAL, Boolean)               \
+  _(GC_ZONE_COUNT, QuantityDistribution)        \
+  _(GC_ZONES_COLLECTED, QuantityDistribution)   \
+  _(GC_MS, TimeDuration_MS)                     \
+  _(GC_BUDGET_MS_2, TimeDuration_MS)            \
+  _(GC_BUDGET_WAS_INCREASED, Boolean)           \
+  _(GC_SLICE_WAS_LONG, Boolean)                 \
+  _(GC_BUDGET_OVERRUN, TimeDuration_US)         \
+  _(GC_ANIMATION_MS, TimeDuration_MS)           \
+  _(GC_MAX_PAUSE_MS_2, TimeDuration_MS)         \
+  _(GC_PREPARE_MS, TimeDuration_MS)             \
+  _(GC_MARK_MS, TimeDuration_MS)                \
+  _(GC_SWEEP_MS, TimeDuration_MS)               \
+  _(GC_COMPACT_MS, TimeDuration_MS)             \
+  _(GC_MARK_ROOTS_US, TimeDuration_US)          \
+  _(GC_MARK_GRAY_MS_2, TimeDuration_MS)         \
+  _(GC_MARK_WEAK_MS, TimeDuration_MS)           \
+  _(GC_SLICE_MS, TimeDuration_MS)               \
+  _(GC_SLOW_PHASE, Enumeration)                 \
+  _(GC_SLOW_TASK, Enumeration)                  \
+  _(GC_MMU_50, Percentage)                      \
+  _(GC_RESET, Boolean)                          \
+  _(GC_RESET_REASON, Enumeration)               \
+  _(GC_NON_INCREMENTAL, Boolean)                \
+  _(GC_NON_INCREMENTAL_REASON, Enumeration)     \
+  _(GC_MINOR_REASON, Enumeration)               \
+  _(GC_MINOR_REASON_LONG, Enumeration)          \
+  _(GC_MINOR_US, TimeDuration_US)               \
+  _(GC_NURSERY_BYTES_2, MemoryDistribution)     \
+  _(GC_PRETENURE_COUNT_2, QuantityDistribution) \
+  _(GC_NURSERY_PROMOTION_RATE, Percentage)      \
+  _(GC_TENURED_SURVIVAL_RATE, Percentage)       \
+  _(GC_MARK_RATE_2, QuantityDistribution)       \
+  _(GC_TIME_BETWEEN_S, TimeDuration_S)          \
+  _(GC_TIME_BETWEEN_SLICES_MS, TimeDuration_MS) \
+  _(GC_SLICE_COUNT, QuantityDistribution)       \
+  _(DESERIALIZE_BYTES, MemoryDistribution)      \
+  _(DESERIALIZE_ITEMS, QuantityDistribution)    \
+  _(DESERIALIZE_US, TimeDuration_US)            \
+  _(GC_EFFECTIVENESS, MemoryDistribution)       \
+  _(GC_PARALLEL_MARK_SPEEDUP, Integer)          \
+  _(GC_PARALLEL_MARK_UTILIZATION, Percentage)   \
+  _(GC_PARALLEL_MARK_INTERRUPTIONS, Integer)    \
+  _(GC_TASK_START_DELAY_US, TimeDuration_US)
+
+// clang-format off
+#define ENUM_DEF(NAME, _) NAME,
+enum class JSMetric {
+  FOR_EACH_JS_METRIC(ENUM_DEF)
+  Count
+};
+#undef ENUM_DEF
+// clang-format on
+
+using JSAccumulateTelemetryDataCallback = void (*)(JSMetric, uint32_t);
+
+extern JS_PUBLIC_API void JS_SetAccumulateTelemetryCallback(
+    JSContext* cx, JSAccumulateTelemetryDataCallback callback);
+
+/*
+ * Use counter names passed to the accumulate use counter callback.
+ *
+ * It's OK to for these enum values to change as they will be mapped to a
+ * fixed member of the mozilla::UseCounter enum by the callback.
+ */
+
+enum class JSUseCounter { ASMJS, WASM };
+
+using JSSetUseCounterCallback = void (*)(JSObject*, JSUseCounter);
+
+extern JS_PUBLIC_API void JS_SetSetUseCounterCallback(
+    JSContext* cx, JSSetUseCounterCallback callback);
+
+#endif  // js_friend_UsageStatistics_h
diff --git a/js/public/friend/WindowProxy.h b/js/public/friend/WindowProxy.h
new file mode 100644
index 0000000000..9023e9e96b
--- /dev/null
+++ b/js/public/friend/WindowProxy.h
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Window and WindowProxy.
+ *
+ * For silly obscure reasons embedders are better off not knowing, the web wants
+ * every global object to exist as two linked components: a Window component
+ * that stores global variables and appears in environment chains but can't be
+ * directly referred to by any script, and a WindowProxy component that
+ * intermediates access to its Window that *can* be directly referred to by
+ * script.  (Thus the global |window| and |globalThis| properties, |this| in
+ * global code, the value of |(function() { return this; })()| in non-strict
+ * mode code, and similar values are WindowProxy objects, not Windows.)
+ *
+ * Maintaining an invariant of never exposing a Window to script requires
+ * substituting in its WindowProxy in a variety of apparently arbitrary (but
+ * actually *very* carefully and nervously selected) places throughout the
+ * engine and indeed the universe.
+ *
+ * This header defines functions that let embeddings convert from a WindowProxy
+ * to its Window and vice versa.
+ *
+ * If you're not embedding SpiderMonkey in a web browser, you can almost
+ * certainly ignore this header.
+ */
+
+#ifndef js_friend_WindowProxy_h
+#define js_friend_WindowProxy_h
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/Class.h"       // JSCLASS_IS_GLOBAL
+#include "js/Object.h"      // JS::GetClass
+#include "js/RootingAPI.h"  // JS::Handle
+
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+
+namespace js {
+
+/**
+ * Tell the JS engine which Class is used for WindowProxy objects. Used by the
+ * functions below.
+ */
+extern JS_PUBLIC_API void SetWindowProxyClass(JSContext* cx,
+                                              const JSClass* clasp);
+
+/**
+ * Associates a WindowProxy with a Window (global object). `windowProxy` must
+ * have the Class set by SetWindowProxyClass.
+ */
+extern JS_PUBLIC_API void SetWindowProxy(JSContext* cx,
+                                         JS::Handle<JSObject*> global,
+                                         JS::Handle<JSObject*> windowProxy);
+
+namespace detail {
+
+extern JS_PUBLIC_API bool IsWindowSlow(JSObject* obj);
+
+extern JS_PUBLIC_API JSObject* ToWindowProxyIfWindowSlow(JSObject* obj);
+
+}  // namespace detail
+
+/**
+ * Returns true iff `obj` is a global object with an associated WindowProxy,
+ * see SetWindowProxy.
+ */
+inline bool IsWindow(JSObject* obj) {
+  if (JS::GetClass(obj)->flags & JSCLASS_IS_GLOBAL) {
+    return detail::IsWindowSlow(obj);
+  }
+  return false;
+}
+
+/**
+ * Returns true iff `obj` has the WindowProxy Class (see SetWindowProxyClass).
+ */
+extern JS_PUBLIC_API bool IsWindowProxy(JSObject* obj);
+
+/**
+ * If `obj` is a Window, get its associated WindowProxy (or a CCW or dead
+ * wrapper if the page was navigated away from), else return `obj`. This
+ * function is infallible and never returns nullptr.
+ */
+MOZ_ALWAYS_INLINE JSObject* ToWindowProxyIfWindow(JSObject* obj) {
+  if (JS::GetClass(obj)->flags & JSCLASS_IS_GLOBAL) {
+    return detail::ToWindowProxyIfWindowSlow(obj);
+  }
+  return obj;
+}
+
+/**
+ * If `obj` is a WindowProxy, get its associated Window (the compartment's
+ * global), else return `obj`. This function is infallible and never returns
+ * nullptr.
+ */
+extern JS_PUBLIC_API JSObject* ToWindowIfWindowProxy(JSObject* obj);
+
+}  // namespace js
+
+#endif  // js_friend_WindowProxy_h
diff --git a/js/public/friend/XrayJitInfo.h b/js/public/friend/XrayJitInfo.h
new file mode 100644
index 0000000000..ddeec6a44f
--- /dev/null
+++ b/js/public/friend/XrayJitInfo.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * JIT info so SpiderMonkey can efficiently work with Gecko XrayWrapper
+ * instances.
+ *
+ * This header is completely irrelevant to non-Gecko embedders.
+ */
+
+#ifndef js_friend_XrayJitInfo_h
+#define js_friend_XrayJitInfo_h
+
+#include <stddef.h>  // size_t
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+class JS_PUBLIC_API JSObject;
+
+namespace js {
+
+class JS_PUBLIC_API BaseProxyHandler;
+
+}  // namespace js
+
+namespace JS {
+
+// Callbacks and other information for use by the JITs when optimizing accesses
+// on xray wrappers.
+struct XrayJitInfo {
+  // Test whether a proxy handler is a cross compartment xray with no
+  // security checks.
+  bool (*isCrossCompartmentXray)(const js::BaseProxyHandler* handler);
+
+  // Test whether xrays in |obj|'s compartment have expandos of their own,
+  // instead of sharing them with Xrays from other compartments.
+  bool (*compartmentHasExclusiveExpandos)(JSObject* obj);
+
+  // Proxy reserved slot used by xrays in sandboxes to store their holder
+  // object.
+  size_t xrayHolderSlot;
+
+  // Reserved slot used by xray holders to store the xray's expando object.
+  size_t holderExpandoSlot;
+
+  // Reserved slot used by xray expandos to store a custom prototype.
+  size_t expandoProtoSlot;
+};
+
+extern JS_PUBLIC_API void SetXrayJitInfo(XrayJitInfo* info);
+
+}  // namespace JS
+
+#endif  // js_friend_XrayJitInfo_h