Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 4806 insertions, 0 deletions

diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
new file mode 100644
index 0000000000..90ba9bcf08
--- /dev/null
+++ b/js/src/jsapi.cpp
@@ -0,0 +1,4806 @@
+/* -*- 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/. */
+
+/*
+ * JavaScript API.
+ */
+
+#include "jsapi.h"
+
+#include "mozilla/FloatingPoint.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/Sprintf.h"
+
+#include <algorithm>
+#include <cstdarg>
+#ifdef __linux__
+#  include <dlfcn.h>
+#endif
+#include <iterator>
+#include <stdarg.h>
+#include <string.h>
+
+#include "jsexn.h"
+#include "jsfriendapi.h"
+#include "jsmath.h"
+#include "jstypes.h"
+
+#include "builtin/AtomicsObject.h"
+#include "builtin/Eval.h"
+#include "builtin/JSON.h"
+#include "builtin/Promise.h"
+#include "builtin/Symbol.h"
+#include "frontend/BytecodeCompiler.h"
+#include "frontend/FrontendContext.h"  // AutoReportFrontendContext
+#include "gc/GC.h"
+#include "gc/GCContext.h"
+#include "gc/Marking.h"
+#include "gc/PublicIterators.h"
+#include "jit/JitSpewer.h"
+#include "js/CallAndConstruct.h"  // JS::IsCallable
+#include "js/CharacterEncoding.h"
+#include "js/CompileOptions.h"
+#include "js/ContextOptions.h"  // JS::ContextOptions{,Ref}
+#include "js/Conversions.h"
+#include "js/ErrorInterceptor.h"
+#include "js/friend/ErrorMessages.h"  // js::GetErrorMessage, JSMSG_*
+#include "js/friend/StackLimits.h"    // js::AutoCheckRecursionLimit
+#include "js/GlobalObject.h"
+#include "js/Initialization.h"
+#include "js/Interrupt.h"
+#include "js/JSON.h"
+#include "js/LocaleSensitive.h"
+#include "js/MemoryCallbacks.h"
+#include "js/MemoryFunctions.h"
+#include "js/PropertySpec.h"
+#include "js/Proxy.h"
+#include "js/ScriptPrivate.h"
+#include "js/StableStringChars.h"
+#include "js/Stack.h"  // JS::NativeStackSize, JS::NativeStackLimitMax, JS::GetNativeStackLimit
+#include "js/StreamConsumer.h"
+#include "js/String.h"  // JS::MaxStringLength
+#include "js/Symbol.h"
+#include "js/TelemetryTimers.h"
+#include "js/Utility.h"
+#include "js/WaitCallbacks.h"
+#include "js/WasmModule.h"
+#include "js/Wrapper.h"
+#include "js/WrapperCallbacks.h"
+#include "proxy/DOMProxy.h"
+#include "util/StringBuffer.h"
+#include "util/Text.h"
+#include "vm/BoundFunctionObject.h"
+#include "vm/EnvironmentObject.h"
+#include "vm/ErrorObject.h"
+#include "vm/ErrorReporting.h"
+#include "vm/FunctionPrefixKind.h"
+#include "vm/Interpreter.h"
+#include "vm/JSAtom.h"
+#include "vm/JSAtomState.h"
+#include "vm/JSContext.h"
+#include "vm/JSFunction.h"
+#include "vm/JSObject.h"
+#include "vm/JSScript.h"
+#include "vm/PlainObject.h"    // js::PlainObject
+#include "vm/PromiseObject.h"  // js::PromiseObject
+#include "vm/Runtime.h"
+#include "vm/SavedStacks.h"
+#include "vm/StringType.h"
+#include "vm/Time.h"
+#include "vm/ToSource.h"
+#include "vm/WrapperObject.h"
+#include "wasm/WasmModule.h"
+#include "wasm/WasmProcess.h"
+
+#include "builtin/Promise-inl.h"
+#include "debugger/DebugAPI-inl.h"
+#include "vm/Compartment-inl.h"
+#include "vm/Interpreter-inl.h"
+#include "vm/IsGivenTypeObject-inl.h"  // js::IsGivenTypeObject
+#include "vm/JSAtom-inl.h"
+#include "vm/JSFunction-inl.h"
+#include "vm/JSScript-inl.h"
+#include "vm/NativeObject-inl.h"
+#include "vm/SavedStacks-inl.h"
+#include "vm/StringType-inl.h"
+
+using namespace js;
+
+using mozilla::Maybe;
+using mozilla::PodCopy;
+using mozilla::Some;
+
+using JS::AutoStableStringChars;
+using JS::CompileOptions;
+using JS::ReadOnlyCompileOptions;
+using JS::SourceText;
+
+// See preprocessor definition of JS_BITS_PER_WORD in jstypes.h; make sure
+// JS_64BIT (used internally) agrees with it
+#ifdef JS_64BIT
+static_assert(JS_BITS_PER_WORD == 64, "values must be in sync");
+#else
+static_assert(JS_BITS_PER_WORD == 32, "values must be in sync");
+#endif
+
+JS_PUBLIC_API void JS::CallArgs::reportMoreArgsNeeded(JSContext* cx,
+                                                      const char* fnname,
+                                                      unsigned required,
+                                                      unsigned actual) {
+  char requiredArgsStr[40];
+  SprintfLiteral(requiredArgsStr, "%u", required);
+  char actualArgsStr[40];
+  SprintfLiteral(actualArgsStr, "%u", actual);
+  JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                            JSMSG_MORE_ARGS_NEEDED, fnname, requiredArgsStr,
+                            required == 1 ? "" : "s", actualArgsStr);
+}
+
+static bool ErrorTakesArguments(unsigned msg) {
+  MOZ_ASSERT(msg < JSErr_Limit);
+  unsigned argCount = js_ErrorFormatString[msg].argCount;
+  MOZ_ASSERT(argCount <= 2);
+  return argCount == 1 || argCount == 2;
+}
+
+static bool ErrorTakesObjectArgument(unsigned msg) {
+  MOZ_ASSERT(msg < JSErr_Limit);
+  unsigned argCount = js_ErrorFormatString[msg].argCount;
+  MOZ_ASSERT(argCount <= 2);
+  return argCount == 2;
+}
+
+bool JS::ObjectOpResult::reportError(JSContext* cx, HandleObject obj,
+                                     HandleId id) {
+  static_assert(unsigned(OkCode) == unsigned(JSMSG_NOT_AN_ERROR),
+                "unsigned value of OkCode must not be an error code");
+  MOZ_ASSERT(code_ != Uninitialized);
+  MOZ_ASSERT(!ok());
+  cx->check(obj);
+
+  if (code_ == JSMSG_OBJECT_NOT_EXTENSIBLE) {
+    RootedValue val(cx, ObjectValue(*obj));
+    return ReportValueError(cx, code_, JSDVG_IGNORE_STACK, val, nullptr);
+  }
+
+  if (ErrorTakesArguments(code_)) {
+    UniqueChars propName =
+        IdToPrintableUTF8(cx, id, IdToPrintableBehavior::IdIsPropertyKey);
+    if (!propName) {
+      return false;
+    }
+
+    if (code_ == JSMSG_SET_NON_OBJECT_RECEIVER) {
+      // We know that the original receiver was a primitive, so unbox it.
+      RootedValue val(cx, ObjectValue(*obj));
+      if (!obj->is<ProxyObject>()) {
+        if (!Unbox(cx, obj, &val)) {
+          return false;
+        }
+      }
+      return ReportValueError(cx, code_, JSDVG_IGNORE_STACK, val, nullptr,
+                              propName.get());
+    }
+
+    if (ErrorTakesObjectArgument(code_)) {
+      JSObject* unwrapped = js::CheckedUnwrapStatic(obj);
+      const char* name = unwrapped ? unwrapped->getClass()->name : "Object";
+      JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, code_, name,
+                               propName.get());
+      return false;
+    }
+
+    JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, code_,
+                             propName.get());
+    return false;
+  }
+  JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, code_);
+  return false;
+}
+
+bool JS::ObjectOpResult::reportError(JSContext* cx, HandleObject obj) {
+  MOZ_ASSERT(code_ != Uninitialized);
+  MOZ_ASSERT(!ok());
+  MOZ_ASSERT(!ErrorTakesArguments(code_));
+  cx->check(obj);
+
+  JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, code_);
+  return false;
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantRedefineProp() {
+  return fail(JSMSG_CANT_REDEFINE_PROP);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failReadOnly() {
+  return fail(JSMSG_READ_ONLY);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failGetterOnly() {
+  return fail(JSMSG_GETTER_ONLY);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDelete() {
+  return fail(JSMSG_CANT_DELETE);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantSetInterposed() {
+  return fail(JSMSG_CANT_SET_INTERPOSED);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDefineWindowElement() {
+  return fail(JSMSG_CANT_DEFINE_WINDOW_ELEMENT);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDeleteWindowElement() {
+  return fail(JSMSG_CANT_DELETE_WINDOW_ELEMENT);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDefineWindowNamedProperty() {
+  return fail(JSMSG_CANT_DEFINE_WINDOW_NAMED_PROPERTY);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDeleteWindowNamedProperty() {
+  return fail(JSMSG_CANT_DELETE_WINDOW_NAMED_PROPERTY);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantDefineWindowNonConfigurable() {
+  return fail(JSMSG_CANT_DEFINE_WINDOW_NC);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantPreventExtensions() {
+  return fail(JSMSG_CANT_PREVENT_EXTENSIONS);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failCantSetProto() {
+  return fail(JSMSG_CANT_SET_PROTO);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failNoNamedSetter() {
+  return fail(JSMSG_NO_NAMED_SETTER);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failNoIndexedSetter() {
+  return fail(JSMSG_NO_INDEXED_SETTER);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failNotDataDescriptor() {
+  return fail(JSMSG_NOT_DATA_DESCRIPTOR);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failInvalidDescriptor() {
+  return fail(JSMSG_INVALID_DESCRIPTOR);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failBadArrayLength() {
+  return fail(JSMSG_BAD_ARRAY_LENGTH);
+}
+
+JS_PUBLIC_API bool JS::ObjectOpResult::failBadIndex() {
+  return fail(JSMSG_BAD_INDEX);
+}
+
+JS_PUBLIC_API int64_t JS_Now() { return PRMJ_Now(); }
+
+JS_PUBLIC_API Value JS_GetEmptyStringValue(JSContext* cx) {
+  return StringValue(cx->runtime()->emptyString);
+}
+
+JS_PUBLIC_API JSString* JS_GetEmptyString(JSContext* cx) {
+  MOZ_ASSERT(cx->emptyString());
+  return cx->emptyString();
+}
+
+namespace js {
+
+void AssertHeapIsIdle() { MOZ_ASSERT(!JS::RuntimeHeapIsBusy()); }
+
+}  // namespace js
+
+static void AssertHeapIsIdleOrIterating() {
+  MOZ_ASSERT(!JS::RuntimeHeapIsCollecting());
+}
+
+JS_PUBLIC_API bool JS_ValueToObject(JSContext* cx, HandleValue value,
+                                    MutableHandleObject objp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  if (value.isNullOrUndefined()) {
+    objp.set(nullptr);
+    return true;
+  }
+  JSObject* obj = ToObject(cx, value);
+  if (!obj) {
+    return false;
+  }
+  objp.set(obj);
+  return true;
+}
+
+JS_PUBLIC_API JSFunction* JS_ValueToFunction(JSContext* cx, HandleValue value) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  return ReportIfNotFunction(cx, value);
+}
+
+JS_PUBLIC_API JSFunction* JS_ValueToConstructor(JSContext* cx,
+                                                HandleValue value) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  return ReportIfNotFunction(cx, value);
+}
+
+JS_PUBLIC_API JSString* JS_ValueToSource(JSContext* cx, HandleValue value) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  return ValueToSource(cx, value);
+}
+
+JS_PUBLIC_API bool JS_DoubleIsInt32(double d, int32_t* ip) {
+  return mozilla::NumberIsInt32(d, ip);
+}
+
+JS_PUBLIC_API JSType JS_TypeOfValue(JSContext* cx, HandleValue value) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  return TypeOfValue(value);
+}
+
+JS_PUBLIC_API bool JS_IsBuiltinEvalFunction(JSFunction* fun) {
+  return IsAnyBuiltinEval(fun);
+}
+
+JS_PUBLIC_API bool JS_IsBuiltinFunctionConstructor(JSFunction* fun) {
+  return fun->isBuiltinFunctionConstructor();
+}
+
+JS_PUBLIC_API bool JS_ObjectIsBoundFunction(JSObject* obj) {
+  return obj->is<BoundFunctionObject>();
+}
+
+JS_PUBLIC_API JSObject* JS_GetBoundFunctionTarget(JSObject* obj) {
+  return obj->is<BoundFunctionObject>()
+             ? obj->as<BoundFunctionObject>().getTarget()
+             : nullptr;
+}
+
+/************************************************************************/
+
+// Prevent functions from being discarded by linker, so that they are callable
+// when debugging.
+static void PreventDiscardingFunctions() {
+  if (reinterpret_cast<uintptr_t>(&PreventDiscardingFunctions) == 1) {
+    // Never executed.
+    memset((void*)&js::debug::GetMarkInfo, 0, 1);
+    memset((void*)&js::debug::GetMarkWordAddress, 0, 1);
+    memset((void*)&js::debug::GetMarkMask, 0, 1);
+  }
+}
+
+JS_PUBLIC_API JSContext* JS_NewContext(uint32_t maxbytes,
+                                       JSRuntime* parentRuntime) {
+  MOZ_ASSERT(JS::detail::libraryInitState == JS::detail::InitState::Running,
+             "must call JS_Init prior to creating any JSContexts");
+
+  // Prevent linker from discarding unused debug functions.
+  PreventDiscardingFunctions();
+
+  // Make sure that all parent runtimes are the topmost parent.
+  while (parentRuntime && parentRuntime->parentRuntime) {
+    parentRuntime = parentRuntime->parentRuntime;
+  }
+
+  return NewContext(maxbytes, parentRuntime);
+}
+
+JS_PUBLIC_API void JS_DestroyContext(JSContext* cx) { DestroyContext(cx); }
+
+JS_PUBLIC_API void* JS_GetContextPrivate(JSContext* cx) { return cx->data; }
+
+JS_PUBLIC_API void JS_SetContextPrivate(JSContext* cx, void* data) {
+  cx->data = data;
+}
+
+JS_PUBLIC_API void JS_SetFutexCanWait(JSContext* cx) {
+  cx->fx.setCanWait(true);
+}
+
+JS_PUBLIC_API JSRuntime* JS_GetParentRuntime(JSContext* cx) {
+  return cx->runtime()->parentRuntime ? cx->runtime()->parentRuntime
+                                      : cx->runtime();
+}
+
+JS_PUBLIC_API JSRuntime* JS_GetRuntime(JSContext* cx) { return cx->runtime(); }
+
+JS_PUBLIC_API JS::ContextOptions& JS::ContextOptionsRef(JSContext* cx) {
+  return cx->options();
+}
+
+JS::ContextOptions& JS::ContextOptions::setFuzzing(bool flag) {
+#ifdef FUZZING
+  fuzzing_ = flag;
+#endif
+  return *this;
+}
+
+JS_PUBLIC_API const char* JS_GetImplementationVersion(void) {
+  return "JavaScript-C" MOZILLA_VERSION;
+}
+
+JS_PUBLIC_API void JS_SetDestroyZoneCallback(JSContext* cx,
+                                             JSDestroyZoneCallback callback) {
+  cx->runtime()->destroyZoneCallback = callback;
+}
+
+JS_PUBLIC_API void JS_SetDestroyCompartmentCallback(
+    JSContext* cx, JSDestroyCompartmentCallback callback) {
+  cx->runtime()->destroyCompartmentCallback = callback;
+}
+
+JS_PUBLIC_API void JS_SetSizeOfIncludingThisCompartmentCallback(
+    JSContext* cx, JSSizeOfIncludingThisCompartmentCallback callback) {
+  cx->runtime()->sizeOfIncludingThisCompartmentCallback = callback;
+}
+
+JS_PUBLIC_API void JS_SetErrorInterceptorCallback(
+    JSRuntime* rt, JSErrorInterceptor* callback) {
+#if defined(NIGHTLY_BUILD)
+  rt->errorInterception.interceptor = callback;
+#endif  // defined(NIGHTLY_BUILD)
+}
+
+JS_PUBLIC_API JSErrorInterceptor* JS_GetErrorInterceptorCallback(
+    JSRuntime* rt) {
+#if defined(NIGHTLY_BUILD)
+  return rt->errorInterception.interceptor;
+#else   // !NIGHTLY_BUILD
+  return nullptr;
+#endif  // defined(NIGHTLY_BUILD)
+}
+
+JS_PUBLIC_API Maybe<JSExnType> JS_GetErrorType(const JS::Value& val) {
+  // All errors are objects.
+  if (!val.isObject()) {
+    return mozilla::Nothing();
+  }
+
+  const JSObject& obj = val.toObject();
+
+  // All errors are `ErrorObject`.
+  if (!obj.is<js::ErrorObject>()) {
+    // Not one of the primitive errors.
+    return mozilla::Nothing();
+  }
+
+  const js::ErrorObject& err = obj.as<js::ErrorObject>();
+  return mozilla::Some(err.type());
+}
+
+JS_PUBLIC_API void JS_SetWrapObjectCallbacks(
+    JSContext* cx, const JSWrapObjectCallbacks* callbacks) {
+  cx->runtime()->wrapObjectCallbacks = callbacks;
+}
+
+JS_PUBLIC_API Realm* JS::EnterRealm(JSContext* cx, JSObject* target) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  MOZ_DIAGNOSTIC_ASSERT(!js::IsCrossCompartmentWrapper(target));
+
+  Realm* oldRealm = cx->realm();
+  cx->enterRealmOf(target);
+  return oldRealm;
+}
+
+JS_PUBLIC_API void JS::LeaveRealm(JSContext* cx, JS::Realm* oldRealm) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->leaveRealm(oldRealm);
+}
+
+JSAutoRealm::JSAutoRealm(JSContext* cx, JSObject* target)
+    : cx_(cx), oldRealm_(cx->realm()) {
+  MOZ_DIAGNOSTIC_ASSERT(!js::IsCrossCompartmentWrapper(target));
+  AssertHeapIsIdleOrIterating();
+  cx_->enterRealmOf(target);
+}
+
+JSAutoRealm::JSAutoRealm(JSContext* cx, JSScript* target)
+    : cx_(cx), oldRealm_(cx->realm()) {
+  AssertHeapIsIdleOrIterating();
+  cx_->enterRealmOf(target);
+}
+
+JSAutoRealm::~JSAutoRealm() { cx_->leaveRealm(oldRealm_); }
+
+JSAutoNullableRealm::JSAutoNullableRealm(JSContext* cx, JSObject* targetOrNull)
+    : cx_(cx), oldRealm_(cx->realm()) {
+  AssertHeapIsIdleOrIterating();
+  if (targetOrNull) {
+    MOZ_DIAGNOSTIC_ASSERT(!js::IsCrossCompartmentWrapper(targetOrNull));
+    cx_->enterRealmOf(targetOrNull);
+  } else {
+    cx_->enterNullRealm();
+  }
+}
+
+JSAutoNullableRealm::~JSAutoNullableRealm() { cx_->leaveRealm(oldRealm_); }
+
+JS_PUBLIC_API void JS_SetCompartmentPrivate(JS::Compartment* compartment,
+                                            void* data) {
+  compartment->data = data;
+}
+
+JS_PUBLIC_API void* JS_GetCompartmentPrivate(JS::Compartment* compartment) {
+  return compartment->data;
+}
+
+JS_PUBLIC_API void JS_MarkCrossZoneId(JSContext* cx, jsid id) {
+  cx->markId(id);
+}
+
+JS_PUBLIC_API void JS_MarkCrossZoneIdValue(JSContext* cx, const Value& value) {
+  cx->markAtomValue(value);
+}
+
+JS_PUBLIC_API void JS_SetZoneUserData(JS::Zone* zone, void* data) {
+  zone->data = data;
+}
+
+JS_PUBLIC_API void* JS_GetZoneUserData(JS::Zone* zone) { return zone->data; }
+
+JS_PUBLIC_API bool JS_WrapObject(JSContext* cx, MutableHandleObject objp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (objp) {
+    JS::ExposeObjectToActiveJS(objp);
+  }
+  return cx->compartment()->wrap(cx, objp);
+}
+
+JS_PUBLIC_API bool JS_WrapValue(JSContext* cx, MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  JS::ExposeValueToActiveJS(vp);
+  return cx->compartment()->wrap(cx, vp);
+}
+
+static void ReleaseAssertObjectHasNoWrappers(JSContext* cx,
+                                             HandleObject target) {
+  for (CompartmentsIter c(cx->runtime()); !c.done(); c.next()) {
+    if (c->lookupWrapper(target)) {
+      MOZ_CRASH("wrapper found for target object");
+    }
+  }
+}
+
+/*
+ * [SMDOC] Brain transplants.
+ *
+ * Not for beginners or the squeamish.
+ *
+ * Sometimes a web spec requires us to transplant an object from one
+ * compartment to another, like when a DOM node is inserted into a document in
+ * another window and thus gets "adopted". We cannot literally change the
+ * `.compartment()` of a `JSObject`; that would break the compartment
+ * invariants. However, as usual, we have a workaround using wrappers.
+ *
+ * Of all the wrapper-based workarounds we do, it's safe to say this is the
+ * most spectacular and questionable.
+ *
+ * `JS_TransplantObject(cx, origobj, target)` changes `origobj` into a
+ * simulacrum of `target`, using highly esoteric means. To JS code, the effect
+ * is as if `origobj` magically "became" `target`, but most often what actually
+ * happens is that `origobj` gets turned into a cross-compartment wrapper for
+ * `target`. The old behavior and contents of `origobj` are overwritten or
+ * discarded.
+ *
+ * Thus, to "transplant" an object from one compartment to another:
+ *
+ * 1.  Let `origobj` be the object that you want to move. First, create a
+ *     clone of it, `target`, in the destination compartment.
+ *
+ *     In our DOM adoption example, `target` will be a Node of the same type as
+ *     `origobj`, same content, but in the adopting document.  We're not done
+ *     yet: the spec for DOM adoption requires that `origobj.ownerDocument`
+ *     actually change. All we've done so far is make a copy.
+ *
+ * 2.  Call `JS_TransplantObject(cx, origobj, target)`. This typically turns
+ *     `origobj` into a wrapper for `target`, so that any JS code that has a
+ *     reference to `origobj` will observe it to have the behavior of `target`
+ *     going forward. In addition, all existing wrappers for `origobj` are
+ *     changed into wrappers for `target`, extending the illusion to those
+ *     compartments as well.
+ *
+ * During navigation, we use the above technique to transplant the WindowProxy
+ * into the new Window's compartment.
+ *
+ * A few rules:
+ *
+ * -   `origobj` and `target` must be two distinct objects of the same
+ *     `JSClass`.  Some classes may not support transplantation; WindowProxy
+ *     objects and DOM nodes are OK.
+ *
+ * -   `target` should be created specifically to be passed to this function.
+ *     There must be no existing cross-compartment wrappers for it; ideally
+ *     there shouldn't be any pointers to it at all, except the one passed in.
+ *
+ * -   `target` shouldn't be used afterwards. Instead, `JS_TransplantObject`
+ *     returns a pointer to the transplanted object, which might be `target`
+ *     but might be some other object in the same compartment. Use that.
+ *
+ * The reason for this last rule is that JS_TransplantObject does very strange
+ * things in some cases, like swapping `target`'s brain with that of another
+ * object. Leaving `target` behaving like its former self is not a goal.
+ *
+ * We don't have a good way to recover from failure in this function, so
+ * we intentionally crash instead.
+ */
+
+static void CheckTransplantObject(JSObject* obj) {
+#ifdef DEBUG
+  MOZ_ASSERT(!obj->is<CrossCompartmentWrapperObject>());
+  JS::AssertCellIsNotGray(obj);
+#endif
+}
+
+JS_PUBLIC_API JSObject* JS_TransplantObject(JSContext* cx, HandleObject origobj,
+                                            HandleObject target) {
+  AssertHeapIsIdle();
+  MOZ_ASSERT(origobj != target);
+  CheckTransplantObject(origobj);
+  CheckTransplantObject(target);
+  ReleaseAssertObjectHasNoWrappers(cx, target);
+
+  RootedObject newIdentity(cx);
+
+  // Don't allow a compacting GC to observe any intermediate state.
+  AutoDisableCompactingGC nocgc(cx);
+
+  AutoDisableProxyCheck adpc;
+
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+
+  JS::Compartment* destination = target->compartment();
+
+  if (origobj->compartment() == destination) {
+    // If the original object is in the same compartment as the
+    // destination, then we know that we won't find a wrapper in the
+    // destination's cross compartment map and that the same
+    // object will continue to work.
+    AutoRealm ar(cx, origobj);
+    JSObject::swap(cx, origobj, target, oomUnsafe);
+    newIdentity = origobj;
+  } else if (ObjectWrapperMap::Ptr p = destination->lookupWrapper(origobj)) {
+    // There might already be a wrapper for the original object in
+    // the new compartment. If there is, we use its identity and swap
+    // in the contents of |target|.
+    newIdentity = p->value().get();
+
+    // When we remove origv from the wrapper map, its wrapper, newIdentity,
+    // must immediately cease to be a cross-compartment wrapper. Nuke it.
+    destination->removeWrapper(p);
+    NukeCrossCompartmentWrapper(cx, newIdentity);
+
+    AutoRealm ar(cx, newIdentity);
+    JSObject::swap(cx, newIdentity, target, oomUnsafe);
+  } else {
+    // Otherwise, we use |target| for the new identity object.
+    newIdentity = target;
+  }
+
+  // Now, iterate through other scopes looking for references to the old
+  // object, and update the relevant cross-compartment wrappers. We do this
+  // even if origobj is in the same compartment as target and thus
+  // `newIdentity == origobj`, because this process also clears out any
+  // cached wrapper state.
+  if (!RemapAllWrappersForObject(cx, origobj, newIdentity)) {
+    oomUnsafe.crash("JS_TransplantObject");
+  }
+
+  // Lastly, update the original object to point to the new one.
+  if (origobj->compartment() != destination) {
+    RootedObject newIdentityWrapper(cx, newIdentity);
+    AutoRealm ar(cx, origobj);
+    if (!JS_WrapObject(cx, &newIdentityWrapper)) {
+      MOZ_RELEASE_ASSERT(cx->isThrowingOutOfMemory() ||
+                         cx->isThrowingOverRecursed());
+      oomUnsafe.crash("JS_TransplantObject");
+    }
+    MOZ_ASSERT(Wrapper::wrappedObject(newIdentityWrapper) == newIdentity);
+    JSObject::swap(cx, origobj, newIdentityWrapper, oomUnsafe);
+    if (origobj->compartment()->lookupWrapper(newIdentity)) {
+      MOZ_ASSERT(origobj->is<CrossCompartmentWrapperObject>());
+      if (!origobj->compartment()->putWrapper(cx, newIdentity, origobj)) {
+        oomUnsafe.crash("JS_TransplantObject");
+      }
+    }
+  }
+
+  // The new identity object might be one of several things. Return it to avoid
+  // ambiguity.
+  JS::AssertCellIsNotGray(newIdentity);
+  return newIdentity;
+}
+
+JS_PUBLIC_API void js::RemapRemoteWindowProxies(
+    JSContext* cx, CompartmentTransplantCallback* callback,
+    MutableHandleObject target) {
+  AssertHeapIsIdle();
+  CheckTransplantObject(target);
+  ReleaseAssertObjectHasNoWrappers(cx, target);
+
+  // |target| can't be a remote proxy, because we expect it to get a CCW when
+  // wrapped across compartments.
+  MOZ_ASSERT(!js::IsDOMRemoteProxyObject(target));
+
+  // Don't allow a compacting GC to observe any intermediate state.
+  AutoDisableCompactingGC nocgc(cx);
+
+  AutoDisableProxyCheck adpc;
+
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+
+  AutoCheckRecursionLimit recursion(cx);
+  if (!recursion.checkSystem(cx)) {
+    oomUnsafe.crash("js::RemapRemoteWindowProxies");
+  }
+
+  RootedObject targetCompartmentProxy(cx);
+  JS::RootedVector<JSObject*> otherProxies(cx);
+
+  // Use the callback to find remote proxies in all compartments that match
+  // whatever criteria callback uses.
+  for (CompartmentsIter c(cx->runtime()); !c.done(); c.next()) {
+    RootedObject remoteProxy(cx, callback->getObjectToTransplant(c));
+    if (!remoteProxy) {
+      continue;
+    }
+    // The object the callback returns should be a DOM remote proxy object in
+    // the compartment c. We rely on it being a DOM remote proxy because that
+    // means that it won't have any cross-compartment wrappers.
+    MOZ_ASSERT(js::IsDOMRemoteProxyObject(remoteProxy));
+    MOZ_ASSERT(remoteProxy->compartment() == c);
+    CheckTransplantObject(remoteProxy);
+
+    // Immediately turn the DOM remote proxy object into a dead proxy object
+    // so we don't have to worry about anything weird going on with it.
+    js::NukeNonCCWProxy(cx, remoteProxy);
+
+    if (remoteProxy->compartment() == target->compartment()) {
+      targetCompartmentProxy = remoteProxy;
+    } else if (!otherProxies.append(remoteProxy)) {
+      oomUnsafe.crash("js::RemapRemoteWindowProxies");
+    }
+  }
+
+  // If there was a remote proxy in |target|'s compartment, we need to use it
+  // instead of |target|, in case it had any references, so swap it. Do this
+  // before any other compartment so that the target object will be set up
+  // correctly before we start wrapping it into other compartments.
+  if (targetCompartmentProxy) {
+    AutoRealm ar(cx, targetCompartmentProxy);
+    JSObject::swap(cx, targetCompartmentProxy, target, oomUnsafe);
+    target.set(targetCompartmentProxy);
+  }
+
+  for (JSObject*& obj : otherProxies) {
+    RootedObject deadWrapper(cx, obj);
+    js::RemapDeadWrapper(cx, deadWrapper, target);
+  }
+}
+
+/*
+ * Recompute all cross-compartment wrappers for an object, resetting state.
+ * Gecko uses this to clear Xray wrappers when doing a navigation that reuses
+ * the inner window and global object.
+ */
+JS_PUBLIC_API bool JS_RefreshCrossCompartmentWrappers(JSContext* cx,
+                                                      HandleObject obj) {
+  return RemapAllWrappersForObject(cx, obj, obj);
+}
+
+typedef struct JSStdName {
+  size_t atomOffset; /* offset of atom pointer in JSAtomState */
+  JSProtoKey key;
+  bool isDummy() const { return key == JSProto_Null; }
+  bool isSentinel() const { return key == JSProto_LIMIT; }
+} JSStdName;
+
+static const JSStdName* LookupStdName(const JSAtomState& names, JSAtom* name,
+                                      const JSStdName* table) {
+  for (unsigned i = 0; !table[i].isSentinel(); i++) {
+    if (table[i].isDummy()) {
+      continue;
+    }
+    JSAtom* atom = AtomStateOffsetToName(names, table[i].atomOffset);
+    MOZ_ASSERT(atom);
+    if (name == atom) {
+      return &table[i];
+    }
+  }
+
+  return nullptr;
+}
+
+/*
+ * Table of standard classes, indexed by JSProtoKey. For entries where the
+ * JSProtoKey does not correspond to a class with a meaningful constructor, we
+ * insert a null entry into the table.
+ */
+#define STD_NAME_ENTRY(name, clasp) {NAME_OFFSET(name), JSProto_##name},
+#define STD_DUMMY_ENTRY(name, dummy) {0, JSProto_Null},
+static const JSStdName standard_class_names[] = {
+    JS_FOR_PROTOTYPES(STD_NAME_ENTRY, STD_DUMMY_ENTRY){0, JSProto_LIMIT}};
+
+/*
+ * Table of top-level function and constant names and the JSProtoKey of the
+ * standard class that initializes them.
+ */
+static const JSStdName builtin_property_names[] = {
+    {NAME_OFFSET(eval), JSProto_Object},
+
+    /* Global properties and functions defined by the Number class. */
+    {NAME_OFFSET(NaN), JSProto_Number},
+    {NAME_OFFSET(Infinity), JSProto_Number},
+    {NAME_OFFSET(isNaN), JSProto_Number},
+    {NAME_OFFSET(isFinite), JSProto_Number},
+    {NAME_OFFSET(parseFloat), JSProto_Number},
+    {NAME_OFFSET(parseInt), JSProto_Number},
+
+    /* String global functions. */
+    {NAME_OFFSET(escape), JSProto_String},
+    {NAME_OFFSET(unescape), JSProto_String},
+    {NAME_OFFSET(decodeURI), JSProto_String},
+    {NAME_OFFSET(encodeURI), JSProto_String},
+    {NAME_OFFSET(decodeURIComponent), JSProto_String},
+    {NAME_OFFSET(encodeURIComponent), JSProto_String},
+    {NAME_OFFSET(uneval), JSProto_String},
+
+    {0, JSProto_LIMIT}};
+
+static bool SkipUneval(jsid id, JSContext* cx) {
+  return !cx->realm()->creationOptions().getToSourceEnabled() &&
+         id == NameToId(cx->names().uneval);
+}
+
+static bool SkipSharedArrayBufferConstructor(JSProtoKey key,
+                                             GlobalObject* global) {
+  if (key != JSProto_SharedArrayBuffer) {
+    return false;
+  }
+
+  const JS::RealmCreationOptions& options = global->realm()->creationOptions();
+  MOZ_ASSERT(options.getSharedMemoryAndAtomicsEnabled(),
+             "shouldn't contemplate defining SharedArrayBuffer if shared "
+             "memory is disabled");
+
+  // On the web, it isn't presently possible to expose the global
+  // "SharedArrayBuffer" property unless the page is cross-site-isolated.  Only
+  // define this constructor if an option on the realm indicates that it should
+  // be defined.
+  return !options.defineSharedArrayBufferConstructor();
+}
+
+JS_PUBLIC_API bool JS_ResolveStandardClass(JSContext* cx, HandleObject obj,
+                                           HandleId id, bool* resolved) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj, id);
+
+  Handle<GlobalObject*> global = obj.as<GlobalObject>();
+  *resolved = false;
+
+  if (!id.isAtom()) {
+    return true;
+  }
+
+  /* Check whether we're resolving 'undefined', and define it if so. */
+  JSAtom* idAtom = id.toAtom();
+  if (idAtom == cx->names().undefined) {
+    *resolved = true;
+    return js::DefineDataProperty(
+        cx, global, id, UndefinedHandleValue,
+        JSPROP_PERMANENT | JSPROP_READONLY | JSPROP_RESOLVING);
+  }
+
+  // Resolve a "globalThis" self-referential property if necessary.
+  if (idAtom == cx->names().globalThis) {
+    return GlobalObject::maybeResolveGlobalThis(cx, global, resolved);
+  }
+
+  // Try for class constructors/prototypes named by well-known atoms.
+  const JSStdName* stdnm =
+      LookupStdName(cx->names(), idAtom, standard_class_names);
+  if (!stdnm) {
+    // Try less frequently used top-level functions and constants.
+    stdnm = LookupStdName(cx->names(), idAtom, builtin_property_names);
+    if (!stdnm) {
+      return true;
+    }
+  }
+
+  JSProtoKey key = stdnm->key;
+  if (key == JSProto_Null || GlobalObject::skipDeselectedConstructor(cx, key) ||
+      SkipUneval(id, cx)) {
+    return true;
+  }
+
+  // If this class is anonymous (or it's "SharedArrayBuffer" but that global
+  // constructor isn't supposed to be defined), then it doesn't exist as a
+  // global property, so we won't resolve anything.
+  const JSClass* clasp = ProtoKeyToClass(key);
+  if (clasp && !clasp->specShouldDefineConstructor()) {
+    return true;
+  }
+  if (SkipSharedArrayBufferConstructor(key, global)) {
+    return true;
+  }
+
+  if (!GlobalObject::ensureConstructor(cx, global, key)) {
+    return false;
+  }
+  *resolved = true;
+  return true;
+}
+
+JS_PUBLIC_API bool JS_MayResolveStandardClass(const JSAtomState& names, jsid id,
+                                              JSObject* maybeObj) {
+  MOZ_ASSERT_IF(maybeObj, maybeObj->is<GlobalObject>());
+
+  // The global object's resolve hook is special: JS_ResolveStandardClass
+  // initializes the prototype chain lazily. Only attempt to optimize here
+  // if we know the prototype chain has been initialized.
+  if (!maybeObj || !maybeObj->staticPrototype()) {
+    return true;
+  }
+
+  if (!id.isAtom()) {
+    return false;
+  }
+
+  JSAtom* atom = id.toAtom();
+
+  // This will return true even for deselected constructors.  (To do
+  // better, we need a JSContext here; it's fine as it is.)
+
+  return atom == names.undefined || atom == names.globalThis ||
+         LookupStdName(names, atom, standard_class_names) ||
+         LookupStdName(names, atom, builtin_property_names);
+}
+
+JS_PUBLIC_API bool JS_EnumerateStandardClasses(JSContext* cx,
+                                               HandleObject obj) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj);
+  Handle<GlobalObject*> global = obj.as<GlobalObject>();
+  return GlobalObject::initStandardClasses(cx, global);
+}
+
+static bool EnumerateStandardClassesInTable(JSContext* cx,
+                                            Handle<GlobalObject*> global,
+                                            MutableHandleIdVector properties,
+                                            const JSStdName* table,
+                                            bool includeResolved) {
+  for (unsigned i = 0; !table[i].isSentinel(); i++) {
+    if (table[i].isDummy()) {
+      continue;
+    }
+
+    JSProtoKey key = table[i].key;
+
+    // If the standard class has been resolved, the properties have been
+    // defined on the global so we don't need to add them here.
+    if (!includeResolved && global->isStandardClassResolved(key)) {
+      continue;
+    }
+
+    if (GlobalObject::skipDeselectedConstructor(cx, key)) {
+      continue;
+    }
+
+    if (const JSClass* clasp = ProtoKeyToClass(key)) {
+      if (!clasp->specShouldDefineConstructor() ||
+          SkipSharedArrayBufferConstructor(key, global)) {
+        continue;
+      }
+    }
+
+    jsid id = NameToId(AtomStateOffsetToName(cx->names(), table[i].atomOffset));
+
+    if (SkipUneval(id, cx)) {
+      continue;
+    }
+
+    if (!properties.append(id)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+static bool EnumerateStandardClasses(JSContext* cx, JS::HandleObject obj,
+                                     JS::MutableHandleIdVector properties,
+                                     bool enumerableOnly,
+                                     bool includeResolved) {
+  if (enumerableOnly) {
+    // There are no enumerable standard classes and "undefined" is
+    // not enumerable.
+    return true;
+  }
+
+  Handle<GlobalObject*> global = obj.as<GlobalObject>();
+
+  // It's fine to always append |undefined| here, it's non-configurable and
+  // the enumeration code filters duplicates.
+  if (!properties.append(NameToId(cx->names().undefined))) {
+    return false;
+  }
+
+  bool resolved = false;
+  if (!GlobalObject::maybeResolveGlobalThis(cx, global, &resolved)) {
+    return false;
+  }
+  if (resolved || includeResolved) {
+    if (!properties.append(NameToId(cx->names().globalThis))) {
+      return false;
+    }
+  }
+
+  if (!EnumerateStandardClassesInTable(cx, global, properties,
+                                       standard_class_names, includeResolved)) {
+    return false;
+  }
+  if (!EnumerateStandardClassesInTable(
+          cx, global, properties, builtin_property_names, includeResolved)) {
+    return false;
+  }
+
+  return true;
+}
+
+JS_PUBLIC_API bool JS_NewEnumerateStandardClasses(
+    JSContext* cx, JS::HandleObject obj, JS::MutableHandleIdVector properties,
+    bool enumerableOnly) {
+  return EnumerateStandardClasses(cx, obj, properties, enumerableOnly, false);
+}
+
+JS_PUBLIC_API bool JS_NewEnumerateStandardClassesIncludingResolved(
+    JSContext* cx, JS::HandleObject obj, JS::MutableHandleIdVector properties,
+    bool enumerableOnly) {
+  return EnumerateStandardClasses(cx, obj, properties, enumerableOnly, true);
+}
+
+JS_PUBLIC_API bool JS_GetClassObject(JSContext* cx, JSProtoKey key,
+                                     MutableHandleObject objp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  JSObject* obj = GlobalObject::getOrCreateConstructor(cx, key);
+  if (!obj) {
+    return false;
+  }
+  objp.set(obj);
+  return true;
+}
+
+JS_PUBLIC_API bool JS_GetClassPrototype(JSContext* cx, JSProtoKey key,
+                                        MutableHandleObject objp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  // Bound functions don't have their own prototype object: they reuse the
+  // prototype of the target object. This is typically Function.prototype so we
+  // use that here.
+  if (key == JSProto_BoundFunction) {
+    key = JSProto_Function;
+  }
+
+  JSObject* proto = GlobalObject::getOrCreatePrototype(cx, key);
+  if (!proto) {
+    return false;
+  }
+  objp.set(proto);
+  return true;
+}
+
+namespace JS {
+
+JS_PUBLIC_API void ProtoKeyToId(JSContext* cx, JSProtoKey key,
+                                MutableHandleId idp) {
+  idp.set(NameToId(ClassName(key, cx)));
+}
+
+} /* namespace JS */
+
+JS_PUBLIC_API JSProtoKey JS_IdToProtoKey(JSContext* cx, HandleId id) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(id);
+
+  if (!id.isAtom()) {
+    return JSProto_Null;
+  }
+
+  JSAtom* atom = id.toAtom();
+  const JSStdName* stdnm =
+      LookupStdName(cx->names(), atom, standard_class_names);
+  if (!stdnm) {
+    return JSProto_Null;
+  }
+
+  if (GlobalObject::skipDeselectedConstructor(cx, stdnm->key)) {
+    return JSProto_Null;
+  }
+
+  if (SkipSharedArrayBufferConstructor(stdnm->key, cx->global())) {
+    MOZ_ASSERT(id == NameToId(cx->names().SharedArrayBuffer));
+    return JSProto_Null;
+  }
+
+  if (SkipUneval(id, cx)) {
+    return JSProto_Null;
+  }
+
+  static_assert(std::size(standard_class_names) == JSProto_LIMIT + 1);
+  return static_cast<JSProtoKey>(stdnm - standard_class_names);
+}
+
+extern JS_PUBLIC_API bool JS_IsGlobalObject(JSObject* obj) {
+  return obj->is<GlobalObject>();
+}
+
+extern JS_PUBLIC_API JSObject* JS_GlobalLexicalEnvironment(JSObject* obj) {
+  return &obj->as<GlobalObject>().lexicalEnvironment();
+}
+
+extern JS_PUBLIC_API bool JS_HasExtensibleLexicalEnvironment(JSObject* obj) {
+  return obj->is<GlobalObject>() ||
+         ObjectRealm::get(obj).getNonSyntacticLexicalEnvironment(obj);
+}
+
+extern JS_PUBLIC_API JSObject* JS_ExtensibleLexicalEnvironment(JSObject* obj) {
+  return ExtensibleLexicalEnvironmentObject::forVarEnvironment(obj);
+}
+
+JS_PUBLIC_API JSObject* JS::CurrentGlobalOrNull(JSContext* cx) {
+  AssertHeapIsIdleOrIterating();
+  CHECK_THREAD(cx);
+  if (!cx->realm()) {
+    return nullptr;
+  }
+  return cx->global();
+}
+
+JS_PUBLIC_API JSObject* JS::GetNonCCWObjectGlobal(JSObject* obj) {
+  AssertHeapIsIdleOrIterating();
+  MOZ_DIAGNOSTIC_ASSERT(!IsCrossCompartmentWrapper(obj));
+  return &obj->nonCCWGlobal();
+}
+
+JS_PUBLIC_API bool JS::detail::ComputeThis(JSContext* cx, Value* vp,
+                                           MutableHandleObject thisObject) {
+  AssertHeapIsIdle();
+  cx->check(vp[0], vp[1]);
+
+  MutableHandleValue thisv = MutableHandleValue::fromMarkedLocation(&vp[1]);
+  JSObject* obj = BoxNonStrictThis(cx, thisv);
+  if (!obj) {
+    return false;
+  }
+
+  thisObject.set(obj);
+  return true;
+}
+
+static bool gProfileTimelineRecordingEnabled = false;
+
+JS_PUBLIC_API void JS::SetProfileTimelineRecordingEnabled(bool enabled) {
+  gProfileTimelineRecordingEnabled = enabled;
+}
+
+JS_PUBLIC_API bool JS::IsProfileTimelineRecordingEnabled() {
+  return gProfileTimelineRecordingEnabled;
+}
+
+JS_PUBLIC_API void* JS_malloc(JSContext* cx, size_t nbytes) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return static_cast<void*>(cx->maybe_pod_malloc<uint8_t>(nbytes));
+}
+
+JS_PUBLIC_API void* JS_realloc(JSContext* cx, void* p, size_t oldBytes,
+                               size_t newBytes) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return static_cast<void*>(cx->maybe_pod_realloc<uint8_t>(
+      static_cast<uint8_t*>(p), oldBytes, newBytes));
+}
+
+JS_PUBLIC_API void JS_free(JSContext* cx, void* p) { return js_free(p); }
+
+JS_PUBLIC_API void* JS_string_malloc(JSContext* cx, size_t nbytes) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return static_cast<void*>(
+      cx->maybe_pod_arena_malloc<uint8_t>(js::StringBufferArena, nbytes));
+}
+
+JS_PUBLIC_API void* JS_string_realloc(JSContext* cx, void* p, size_t oldBytes,
+                                      size_t newBytes) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return static_cast<void*>(cx->maybe_pod_arena_realloc<uint8_t>(
+      js::StringBufferArena, static_cast<uint8_t*>(p), oldBytes, newBytes));
+}
+
+JS_PUBLIC_API void JS_string_free(JSContext* cx, void* p) { return js_free(p); }
+
+JS_PUBLIC_API void JS::AddAssociatedMemory(JSObject* obj, size_t nbytes,
+                                           JS::MemoryUse use) {
+  MOZ_ASSERT(obj);
+  if (!nbytes) {
+    return;
+  }
+
+  Zone* zone = obj->zone();
+  MOZ_ASSERT(!IsInsideNursery(obj));
+  zone->addCellMemory(obj, nbytes, js::MemoryUse(use));
+  zone->maybeTriggerGCOnMalloc();
+}
+
+JS_PUBLIC_API void JS::RemoveAssociatedMemory(JSObject* obj, size_t nbytes,
+                                              JS::MemoryUse use) {
+  MOZ_ASSERT(obj);
+  if (!nbytes) {
+    return;
+  }
+
+  GCContext* gcx = obj->runtimeFromMainThread()->gcContext();
+  gcx->removeCellMemory(obj, nbytes, js::MemoryUse(use));
+}
+
+#undef JS_AddRoot
+
+JS_PUBLIC_API bool JS_AddExtraGCRootsTracer(JSContext* cx,
+                                            JSTraceDataOp traceOp, void* data) {
+  return cx->runtime()->gc.addBlackRootsTracer(traceOp, data);
+}
+
+JS_PUBLIC_API void JS_RemoveExtraGCRootsTracer(JSContext* cx,
+                                               JSTraceDataOp traceOp,
+                                               void* data) {
+  return cx->runtime()->gc.removeBlackRootsTracer(traceOp, data);
+}
+
+JS_PUBLIC_API JS::GCReason JS::WantEagerMinorGC(JSRuntime* rt) {
+  if (rt->gc.nursery().shouldCollect()) {
+    return JS::GCReason::EAGER_NURSERY_COLLECTION;
+  }
+  return JS::GCReason::NO_REASON;
+}
+
+JS_PUBLIC_API JS::GCReason JS::WantEagerMajorGC(JSRuntime* rt) {
+  return rt->gc.wantMajorGC(true);
+}
+
+JS_PUBLIC_API void JS::MaybeRunNurseryCollection(JSRuntime* rt,
+                                                 JS::GCReason reason) {
+  gc::GCRuntime& gc = rt->gc;
+  if (gc.nursery().shouldCollect()) {
+    gc.minorGC(reason);
+  }
+}
+
+JS_PUBLIC_API void JS_GC(JSContext* cx, JS::GCReason reason) {
+  AssertHeapIsIdle();
+  JS::PrepareForFullGC(cx);
+  cx->runtime()->gc.gc(JS::GCOptions::Normal, reason);
+}
+
+JS_PUBLIC_API void JS_MaybeGC(JSContext* cx) {
+  AssertHeapIsIdle();
+  cx->runtime()->gc.maybeGC();
+}
+
+JS_PUBLIC_API void JS_SetGCCallback(JSContext* cx, JSGCCallback cb,
+                                    void* data) {
+  AssertHeapIsIdle();
+  cx->runtime()->gc.setGCCallback(cb, data);
+}
+
+JS_PUBLIC_API void JS_SetObjectsTenuredCallback(JSContext* cx,
+                                                JSObjectsTenuredCallback cb,
+                                                void* data) {
+  AssertHeapIsIdle();
+  cx->runtime()->gc.setObjectsTenuredCallback(cb, data);
+}
+
+JS_PUBLIC_API bool JS_AddFinalizeCallback(JSContext* cx, JSFinalizeCallback cb,
+                                          void* data) {
+  AssertHeapIsIdle();
+  return cx->runtime()->gc.addFinalizeCallback(cb, data);
+}
+
+JS_PUBLIC_API void JS_RemoveFinalizeCallback(JSContext* cx,
+                                             JSFinalizeCallback cb) {
+  cx->runtime()->gc.removeFinalizeCallback(cb);
+}
+
+JS_PUBLIC_API void JS::SetHostCleanupFinalizationRegistryCallback(
+    JSContext* cx, JSHostCleanupFinalizationRegistryCallback cb, void* data) {
+  AssertHeapIsIdle();
+  cx->runtime()->gc.setHostCleanupFinalizationRegistryCallback(cb, data);
+}
+
+JS_PUBLIC_API void JS::ClearKeptObjects(JSContext* cx) {
+  gc::GCRuntime* gc = &cx->runtime()->gc;
+
+  for (ZonesIter zone(gc, ZoneSelector::WithAtoms); !zone.done(); zone.next()) {
+    zone->clearKeptObjects();
+  }
+}
+
+JS_PUBLIC_API bool JS::AtomsZoneIsCollecting(JSRuntime* runtime) {
+  return runtime->activeGCInAtomsZone();
+}
+
+JS_PUBLIC_API bool JS::IsAtomsZone(JS::Zone* zone) {
+  return zone->isAtomsZone();
+}
+
+JS_PUBLIC_API bool JS_AddWeakPointerZonesCallback(JSContext* cx,
+                                                  JSWeakPointerZonesCallback cb,
+                                                  void* data) {
+  AssertHeapIsIdle();
+  return cx->runtime()->gc.addWeakPointerZonesCallback(cb, data);
+}
+
+JS_PUBLIC_API void JS_RemoveWeakPointerZonesCallback(
+    JSContext* cx, JSWeakPointerZonesCallback cb) {
+  cx->runtime()->gc.removeWeakPointerZonesCallback(cb);
+}
+
+JS_PUBLIC_API bool JS_AddWeakPointerCompartmentCallback(
+    JSContext* cx, JSWeakPointerCompartmentCallback cb, void* data) {
+  AssertHeapIsIdle();
+  return cx->runtime()->gc.addWeakPointerCompartmentCallback(cb, data);
+}
+
+JS_PUBLIC_API void JS_RemoveWeakPointerCompartmentCallback(
+    JSContext* cx, JSWeakPointerCompartmentCallback cb) {
+  cx->runtime()->gc.removeWeakPointerCompartmentCallback(cb);
+}
+
+JS_PUBLIC_API bool JS_UpdateWeakPointerAfterGC(JSTracer* trc,
+                                               JS::Heap<JSObject*>* objp) {
+  return TraceWeakEdge(trc, objp);
+}
+
+JS_PUBLIC_API bool JS_UpdateWeakPointerAfterGCUnbarriered(JSTracer* trc,
+                                                          JSObject** objp) {
+  return TraceManuallyBarrieredWeakEdge(trc, objp, "External weak pointer");
+}
+
+JS_PUBLIC_API void JS_SetGCParameter(JSContext* cx, JSGCParamKey key,
+                                     uint32_t value) {
+  MOZ_ALWAYS_TRUE(cx->runtime()->gc.setParameter(cx, key, value));
+}
+
+JS_PUBLIC_API void JS_ResetGCParameter(JSContext* cx, JSGCParamKey key) {
+  cx->runtime()->gc.resetParameter(cx, key);
+}
+
+JS_PUBLIC_API uint32_t JS_GetGCParameter(JSContext* cx, JSGCParamKey key) {
+  return cx->runtime()->gc.getParameter(key);
+}
+
+JS_PUBLIC_API void JS_SetGCParametersBasedOnAvailableMemory(
+    JSContext* cx, uint32_t availMemMB) {
+  struct JSGCConfig {
+    JSGCParamKey key;
+    uint32_t value;
+  };
+
+  static const JSGCConfig minimal[] = {
+      {JSGC_SLICE_TIME_BUDGET_MS, 5},
+      {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1500},
+      {JSGC_LARGE_HEAP_SIZE_MIN, 250},
+      {JSGC_SMALL_HEAP_SIZE_MAX, 50},
+      {JSGC_HIGH_FREQUENCY_SMALL_HEAP_GROWTH, 300},
+      {JSGC_HIGH_FREQUENCY_LARGE_HEAP_GROWTH, 120},
+      {JSGC_LOW_FREQUENCY_HEAP_GROWTH, 120},
+      {JSGC_ALLOCATION_THRESHOLD, 15},
+      {JSGC_MALLOC_THRESHOLD_BASE, 20},
+      {JSGC_SMALL_HEAP_INCREMENTAL_LIMIT, 200},
+      {JSGC_LARGE_HEAP_INCREMENTAL_LIMIT, 110},
+      {JSGC_URGENT_THRESHOLD_MB, 8}};
+
+  static const JSGCConfig nominal[] = {
+      {JSGC_SLICE_TIME_BUDGET_MS, 5},
+      {JSGC_HIGH_FREQUENCY_TIME_LIMIT, 1000},
+      {JSGC_LARGE_HEAP_SIZE_MIN, 500},
+      {JSGC_SMALL_HEAP_SIZE_MAX, 100},
+      {JSGC_HIGH_FREQUENCY_SMALL_HEAP_GROWTH, 300},
+      {JSGC_HIGH_FREQUENCY_LARGE_HEAP_GROWTH, 150},
+      {JSGC_LOW_FREQUENCY_HEAP_GROWTH, 150},
+      {JSGC_ALLOCATION_THRESHOLD, 27},
+      {JSGC_MALLOC_THRESHOLD_BASE, 38},
+      {JSGC_SMALL_HEAP_INCREMENTAL_LIMIT, 150},
+      {JSGC_LARGE_HEAP_INCREMENTAL_LIMIT, 110},
+      {JSGC_URGENT_THRESHOLD_MB, 16}};
+
+  const auto& configSet = availMemMB > 512 ? nominal : minimal;
+  for (const auto& config : configSet) {
+    JS_SetGCParameter(cx, config.key, config.value);
+  }
+}
+
+JS_PUBLIC_API JSString* JS_NewExternalString(
+    JSContext* cx, const char16_t* chars, size_t length,
+    const JSExternalStringCallbacks* callbacks) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return JSExternalString::new_(cx, chars, length, callbacks);
+}
+
+JS_PUBLIC_API JSString* JS_NewMaybeExternalString(
+    JSContext* cx, const char16_t* chars, size_t length,
+    const JSExternalStringCallbacks* callbacks, bool* allocatedExternal) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewMaybeExternalString(cx, chars, length, callbacks,
+                                allocatedExternal);
+}
+
+extern JS_PUBLIC_API const JSExternalStringCallbacks*
+JS_GetExternalStringCallbacks(JSString* str) {
+  return str->asExternal().callbacks();
+}
+
+static void SetNativeStackSize(JSContext* cx, JS::StackKind kind,
+                               JS::NativeStackSize stackSize) {
+#ifdef __wasi__
+  cx->nativeStackLimit[kind] = JS::WASINativeStackLimit;
+#else   // __wasi__
+  if (stackSize == 0) {
+    cx->nativeStackLimit[kind] = JS::NativeStackLimitMax;
+  } else {
+    cx->nativeStackLimit[kind] =
+        JS::GetNativeStackLimit(cx->nativeStackBase(), stackSize - 1);
+  }
+#endif  // !__wasi__
+}
+
+JS_PUBLIC_API void JS_SetNativeStackQuota(
+    JSContext* cx, JS::NativeStackSize systemCodeStackSize,
+    JS::NativeStackSize trustedScriptStackSize,
+    JS::NativeStackSize untrustedScriptStackSize) {
+  MOZ_ASSERT(!cx->activation());
+  MOZ_ASSERT(cx->isMainThreadContext());
+
+  if (!trustedScriptStackSize) {
+    trustedScriptStackSize = systemCodeStackSize;
+  } else {
+    MOZ_ASSERT(trustedScriptStackSize < systemCodeStackSize);
+  }
+
+  if (!untrustedScriptStackSize) {
+    untrustedScriptStackSize = trustedScriptStackSize;
+  } else {
+    MOZ_ASSERT(untrustedScriptStackSize < trustedScriptStackSize);
+  }
+
+  SetNativeStackSize(cx, JS::StackForSystemCode, systemCodeStackSize);
+  SetNativeStackSize(cx, JS::StackForTrustedScript, trustedScriptStackSize);
+  SetNativeStackSize(cx, JS::StackForUntrustedScript, untrustedScriptStackSize);
+
+  cx->initJitStackLimit();
+}
+
+/************************************************************************/
+
+JS_PUBLIC_API bool JS_ValueToId(JSContext* cx, HandleValue value,
+                                MutableHandleId idp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+  return ToPropertyKey(cx, value, idp);
+}
+
+JS_PUBLIC_API bool JS_StringToId(JSContext* cx, HandleString string,
+                                 MutableHandleId idp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(string);
+  RootedValue value(cx, StringValue(string));
+  return PrimitiveValueToId<CanGC>(cx, value, idp);
+}
+
+JS_PUBLIC_API bool JS_IdToValue(JSContext* cx, jsid id, MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(id);
+  vp.set(IdToValue(id));
+  cx->check(vp);
+  return true;
+}
+
+JS_PUBLIC_API bool JS::ToPrimitive(JSContext* cx, HandleObject obj, JSType hint,
+                                   MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj);
+  MOZ_ASSERT(obj != nullptr);
+  MOZ_ASSERT(hint == JSTYPE_UNDEFINED || hint == JSTYPE_STRING ||
+             hint == JSTYPE_NUMBER);
+  vp.setObject(*obj);
+  return ToPrimitiveSlow(cx, hint, vp);
+}
+
+JS_PUBLIC_API bool JS::GetFirstArgumentAsTypeHint(JSContext* cx, CallArgs args,
+                                                  JSType* result) {
+  if (!args.get(0).isString()) {
+    JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                              JSMSG_NOT_EXPECTED_TYPE, "Symbol.toPrimitive",
+                              "\"string\", \"number\", or \"default\"",
+                              InformalValueTypeName(args.get(0)));
+    return false;
+  }
+
+  RootedString str(cx, args.get(0).toString());
+  bool match;
+
+  if (!EqualStrings(cx, str, cx->names().default_, &match)) {
+    return false;
+  }
+  if (match) {
+    *result = JSTYPE_UNDEFINED;
+    return true;
+  }
+
+  if (!EqualStrings(cx, str, cx->names().string, &match)) {
+    return false;
+  }
+  if (match) {
+    *result = JSTYPE_STRING;
+    return true;
+  }
+
+  if (!EqualStrings(cx, str, cx->names().number, &match)) {
+    return false;
+  }
+  if (match) {
+    *result = JSTYPE_NUMBER;
+    return true;
+  }
+
+  UniqueChars bytes;
+  const char* source = ValueToSourceForError(cx, args.get(0), bytes);
+  if (!source) {
+    ReportOutOfMemory(cx);
+    return false;
+  }
+
+  JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr,
+                           JSMSG_NOT_EXPECTED_TYPE, "Symbol.toPrimitive",
+                           "\"string\", \"number\", or \"default\"", source);
+  return false;
+}
+
+JS_PUBLIC_API JSObject* JS_InitClass(
+    JSContext* cx, HandleObject obj, const JSClass* protoClass,
+    HandleObject protoProto, const char* name, JSNative constructor,
+    unsigned nargs, const JSPropertySpec* ps, const JSFunctionSpec* fs,
+    const JSPropertySpec* static_ps, const JSFunctionSpec* static_fs) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj, protoProto);
+  return InitClass(cx, obj, protoClass, protoProto, name, constructor, nargs,
+                   ps, fs, static_ps, static_fs);
+}
+
+JS_PUBLIC_API bool JS_LinkConstructorAndPrototype(JSContext* cx,
+                                                  HandleObject ctor,
+                                                  HandleObject proto) {
+  return LinkConstructorAndPrototype(cx, ctor, proto);
+}
+
+JS_PUBLIC_API bool JS_InstanceOf(JSContext* cx, HandleObject obj,
+                                 const JSClass* clasp, CallArgs* args) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+#ifdef DEBUG
+  if (args) {
+    cx->check(obj);
+    cx->check(args->thisv(), args->calleev());
+  }
+#endif
+  if (!obj || obj->getClass() != clasp) {
+    if (args) {
+      ReportIncompatibleMethod(cx, *args, clasp);
+    }
+    return false;
+  }
+  return true;
+}
+
+JS_PUBLIC_API bool JS_HasInstance(JSContext* cx, HandleObject obj,
+                                  HandleValue value, bool* bp) {
+  AssertHeapIsIdle();
+  cx->check(obj, value);
+  return InstanceofOperator(cx, obj, value, bp);
+}
+
+JS_PUBLIC_API JSObject* JS_GetConstructor(JSContext* cx, HandleObject proto) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(proto);
+
+  RootedValue cval(cx);
+  if (!GetProperty(cx, proto, proto, cx->names().constructor, &cval)) {
+    return nullptr;
+  }
+  if (!IsFunctionObject(cval)) {
+    JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                              JSMSG_NO_CONSTRUCTOR, proto->getClass()->name);
+    return nullptr;
+  }
+  return &cval.toObject();
+}
+
+JS::RealmCreationOptions&
+JS::RealmCreationOptions::setNewCompartmentInSystemZone() {
+  compSpec_ = CompartmentSpecifier::NewCompartmentInSystemZone;
+  comp_ = nullptr;
+  return *this;
+}
+
+JS::RealmCreationOptions&
+JS::RealmCreationOptions::setNewCompartmentInExistingZone(JSObject* obj) {
+  compSpec_ = CompartmentSpecifier::NewCompartmentInExistingZone;
+  zone_ = obj->zone();
+  return *this;
+}
+
+JS::RealmCreationOptions& JS::RealmCreationOptions::setExistingCompartment(
+    JSObject* obj) {
+  compSpec_ = CompartmentSpecifier::ExistingCompartment;
+  comp_ = obj->compartment();
+  return *this;
+}
+
+JS::RealmCreationOptions& JS::RealmCreationOptions::setExistingCompartment(
+    JS::Compartment* compartment) {
+  compSpec_ = CompartmentSpecifier::ExistingCompartment;
+  comp_ = compartment;
+  return *this;
+}
+
+JS::RealmCreationOptions& JS::RealmCreationOptions::setNewCompartmentAndZone() {
+  compSpec_ = CompartmentSpecifier::NewCompartmentAndZone;
+  comp_ = nullptr;
+  return *this;
+}
+
+const JS::RealmCreationOptions& JS::RealmCreationOptionsRef(Realm* realm) {
+  return realm->creationOptions();
+}
+
+const JS::RealmCreationOptions& JS::RealmCreationOptionsRef(JSContext* cx) {
+  return cx->realm()->creationOptions();
+}
+
+bool JS::RealmCreationOptions::getSharedMemoryAndAtomicsEnabled() const {
+  return sharedMemoryAndAtomics_;
+}
+
+JS::RealmCreationOptions&
+JS::RealmCreationOptions::setSharedMemoryAndAtomicsEnabled(bool flag) {
+  sharedMemoryAndAtomics_ = flag;
+  return *this;
+}
+
+bool JS::RealmCreationOptions::getCoopAndCoepEnabled() const {
+  return coopAndCoep_;
+}
+
+JS::RealmCreationOptions& JS::RealmCreationOptions::setCoopAndCoepEnabled(
+    bool flag) {
+  coopAndCoep_ = flag;
+  return *this;
+}
+
+const JS::RealmBehaviors& JS::RealmBehaviorsRef(JS::Realm* realm) {
+  return realm->behaviors();
+}
+
+const JS::RealmBehaviors& JS::RealmBehaviorsRef(JSContext* cx) {
+  return cx->realm()->behaviors();
+}
+
+void JS::SetRealmNonLive(Realm* realm) { realm->setNonLive(); }
+
+JS_PUBLIC_API JSObject* JS_NewGlobalObject(JSContext* cx, const JSClass* clasp,
+                                           JSPrincipals* principals,
+                                           JS::OnNewGlobalHookOption hookOption,
+                                           const JS::RealmOptions& options) {
+  MOZ_RELEASE_ASSERT(
+      cx->runtime()->hasInitializedSelfHosting(),
+      "Must call JS::InitSelfHostedCode() before creating a global");
+
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return GlobalObject::new_(cx, clasp, principals, hookOption, options);
+}
+
+JS_PUBLIC_API void JS_GlobalObjectTraceHook(JSTracer* trc, JSObject* global) {
+  GlobalObject* globalObj = &global->as<GlobalObject>();
+  Realm* globalRealm = globalObj->realm();
+
+  // If we GC when creating the global, we may not have set that global's
+  // realm's global pointer yet. In this case, the realm will not yet contain
+  // anything that needs to be traced.
+  if (globalRealm->unsafeUnbarrieredMaybeGlobal() != globalObj) {
+    return;
+  }
+
+  // Trace the realm for any GC things that should only stick around if we
+  // know the global is live.
+  globalRealm->traceGlobalData(trc);
+
+  globalObj->traceData(trc, globalObj);
+
+  if (JSTraceOp trace = globalRealm->creationOptions().getTrace()) {
+    trace(trc, global);
+  }
+}
+
+const JSClassOps JS::DefaultGlobalClassOps = {
+    nullptr,                         // addProperty
+    nullptr,                         // delProperty
+    nullptr,                         // enumerate
+    JS_NewEnumerateStandardClasses,  // newEnumerate
+    JS_ResolveStandardClass,         // resolve
+    JS_MayResolveStandardClass,      // mayResolve
+    nullptr,                         // finalize
+    nullptr,                         // call
+    nullptr,                         // construct
+    JS_GlobalObjectTraceHook,        // trace
+};
+
+JS_PUBLIC_API void JS_FireOnNewGlobalObject(JSContext* cx,
+                                            JS::HandleObject global) {
+  // This hook is infallible, because we don't really want arbitrary script
+  // to be able to throw errors during delicate global creation routines.
+  // This infallibility will eat OOM and slow script, but if that happens
+  // we'll likely run up into them again soon in a fallible context.
+  cx->check(global);
+  Rooted<js::GlobalObject*> globalObject(cx, &global->as<GlobalObject>());
+  DebugAPI::onNewGlobalObject(cx, globalObject);
+  cx->runtime()->ensureRealmIsRecordingAllocations(globalObject);
+}
+
+JS_PUBLIC_API JSObject* JS_NewObject(JSContext* cx, const JSClass* clasp) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (!clasp) {
+    // Default class is Object.
+    return NewPlainObject(cx);
+  }
+
+  MOZ_ASSERT(!clasp->isJSFunction());
+  MOZ_ASSERT(clasp != &PlainObject::class_);
+  MOZ_ASSERT(clasp != &ArrayObject::class_);
+  MOZ_ASSERT(!(clasp->flags & JSCLASS_IS_GLOBAL));
+
+  return NewBuiltinClassInstance(cx, clasp);
+}
+
+JS_PUBLIC_API JSObject* JS_NewObjectWithGivenProto(JSContext* cx,
+                                                   const JSClass* clasp,
+                                                   HandleObject proto) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(proto);
+
+  if (!clasp) {
+    // Default class is Object.
+    return NewPlainObjectWithProto(cx, proto);
+  }
+
+  MOZ_ASSERT(!clasp->isJSFunction());
+  MOZ_ASSERT(clasp != &PlainObject::class_);
+  MOZ_ASSERT(clasp != &ArrayObject::class_);
+  MOZ_ASSERT(!(clasp->flags & JSCLASS_IS_GLOBAL));
+
+  return NewObjectWithGivenProto(cx, clasp, proto);
+}
+
+JS_PUBLIC_API JSObject* JS_NewPlainObject(JSContext* cx) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return NewPlainObject(cx);
+}
+
+JS_PUBLIC_API JSObject* JS_NewObjectForConstructor(JSContext* cx,
+                                                   const JSClass* clasp,
+                                                   const CallArgs& args) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  MOZ_ASSERT(!clasp->isJSFunction());
+  MOZ_ASSERT(clasp != &PlainObject::class_);
+  MOZ_ASSERT(clasp != &ArrayObject::class_);
+  MOZ_ASSERT(!(clasp->flags & JSCLASS_IS_GLOBAL));
+
+  if (!ThrowIfNotConstructing(cx, args, clasp->name)) {
+    return nullptr;
+  }
+
+  RootedObject newTarget(cx, &args.newTarget().toObject());
+  cx->check(newTarget);
+
+  RootedObject proto(cx);
+  if (!GetPrototypeFromConstructor(cx, newTarget,
+                                   JSCLASS_CACHED_PROTO_KEY(clasp), &proto)) {
+    return nullptr;
+  }
+
+  return NewObjectWithClassProto(cx, clasp, proto);
+}
+
+JS_PUBLIC_API bool JS_IsNative(JSObject* obj) {
+  return obj->is<NativeObject>();
+}
+
+JS_PUBLIC_API void JS::AssertObjectBelongsToCurrentThread(JSObject* obj) {
+  JSRuntime* rt = obj->compartment()->runtimeFromAnyThread();
+  MOZ_RELEASE_ASSERT(CurrentThreadCanAccessRuntime(rt));
+}
+
+JS_PUBLIC_API void JS::SetFilenameValidationCallback(
+    JS::FilenameValidationCallback cb) {
+  js::gFilenameValidationCallback = cb;
+}
+
+JS_PUBLIC_API void JS::SetHostEnsureCanAddPrivateElementHook(
+    JSContext* cx, JS::EnsureCanAddPrivateElementOp op) {
+  cx->runtime()->canAddPrivateElement = op;
+}
+
+/*** Standard internal methods **********************************************/
+
+JS_PUBLIC_API bool JS_GetPrototype(JSContext* cx, HandleObject obj,
+                                   MutableHandleObject result) {
+  cx->check(obj);
+  return GetPrototype(cx, obj, result);
+}
+
+JS_PUBLIC_API bool JS_SetPrototype(JSContext* cx, HandleObject obj,
+                                   HandleObject proto) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj, proto);
+
+  return SetPrototype(cx, obj, proto);
+}
+
+JS_PUBLIC_API bool JS_GetPrototypeIfOrdinary(JSContext* cx, HandleObject obj,
+                                             bool* isOrdinary,
+                                             MutableHandleObject result) {
+  cx->check(obj);
+  return GetPrototypeIfOrdinary(cx, obj, isOrdinary, result);
+}
+
+JS_PUBLIC_API bool JS_IsExtensible(JSContext* cx, HandleObject obj,
+                                   bool* extensible) {
+  cx->check(obj);
+  return IsExtensible(cx, obj, extensible);
+}
+
+JS_PUBLIC_API bool JS_PreventExtensions(JSContext* cx, JS::HandleObject obj,
+                                        ObjectOpResult& result) {
+  cx->check(obj);
+  return PreventExtensions(cx, obj, result);
+}
+
+JS_PUBLIC_API bool JS_SetImmutablePrototype(JSContext* cx, JS::HandleObject obj,
+                                            bool* succeeded) {
+  cx->check(obj);
+  return SetImmutablePrototype(cx, obj, succeeded);
+}
+
+/* * */
+
+JS_PUBLIC_API bool JS_FreezeObject(JSContext* cx, HandleObject obj) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj);
+  return FreezeObject(cx, obj);
+}
+
+static bool DeepFreezeSlot(JSContext* cx, const Value& v) {
+  if (v.isPrimitive()) {
+    return true;
+  }
+  RootedObject obj(cx, &v.toObject());
+  return JS_DeepFreezeObject(cx, obj);
+}
+
+JS_PUBLIC_API bool JS_DeepFreezeObject(JSContext* cx, HandleObject obj) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj);
+
+  // Assume that non-extensible objects are already deep-frozen, to avoid
+  // divergence.
+  bool extensible;
+  if (!IsExtensible(cx, obj, &extensible)) {
+    return false;
+  }
+  if (!extensible) {
+    return true;
+  }
+
+  if (!FreezeObject(cx, obj)) {
+    return false;
+  }
+
+  // Walk slots in obj and if any value is a non-null object, seal it.
+  if (obj->is<NativeObject>()) {
+    Rooted<NativeObject*> nobj(cx, &obj->as<NativeObject>());
+    for (uint32_t i = 0, n = nobj->slotSpan(); i < n; ++i) {
+      if (!DeepFreezeSlot(cx, nobj->getSlot(i))) {
+        return false;
+      }
+    }
+    for (uint32_t i = 0, n = nobj->getDenseInitializedLength(); i < n; ++i) {
+      if (!DeepFreezeSlot(cx, nobj->getDenseElement(i))) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+JS_PUBLIC_API bool JSPropertySpec::getValue(JSContext* cx,
+                                            MutableHandleValue vp) const {
+  MOZ_ASSERT(!isAccessor());
+
+  switch (u.value.type) {
+    case ValueWrapper::Type::String: {
+      Rooted<JSAtom*> atom(cx,
+                           Atomize(cx, u.value.string, strlen(u.value.string)));
+      if (!atom) {
+        return false;
+      }
+      vp.setString(atom);
+      return true;
+    }
+
+    case ValueWrapper::Type::Int32:
+      vp.setInt32(u.value.int32);
+      return true;
+
+    case ValueWrapper::Type::Double:
+      vp.setDouble(u.value.double_);
+      return true;
+  }
+
+  MOZ_CRASH("Unexpected type");
+}
+
+bool PropertySpecNameToId(JSContext* cx, JSPropertySpec::Name name,
+                          MutableHandleId id) {
+  if (name.isSymbol()) {
+    id.set(PropertyKey::Symbol(cx->wellKnownSymbols().get(name.symbol())));
+  } else {
+    JSAtom* atom = Atomize(cx, name.string(), strlen(name.string()));
+    if (!atom) {
+      return false;
+    }
+    id.set(AtomToId(atom));
+  }
+  return true;
+}
+
+JS_PUBLIC_API bool JS::PropertySpecNameToPermanentId(JSContext* cx,
+                                                     JSPropertySpec::Name name,
+                                                     jsid* idp) {
+  // We are calling fromMarkedLocation(idp) even though idp points to a
+  // location that will never be marked. This is OK because the whole point
+  // of this API is to populate *idp with a jsid that does not need to be
+  // marked.
+  MutableHandleId id = MutableHandleId::fromMarkedLocation(idp);
+  if (!PropertySpecNameToId(cx, name, id)) {
+    return false;
+  }
+
+  if (id.isString() && !PinAtom(cx, &id.toString()->asAtom())) {
+    return false;
+  }
+
+  return true;
+}
+
+JS_PUBLIC_API bool JS::ObjectToCompletePropertyDescriptor(
+    JSContext* cx, HandleObject obj, HandleValue descObj,
+    MutableHandle<PropertyDescriptor> desc) {
+  // |obj| can be in a different compartment here. The caller is responsible
+  // for wrapping it (see JS_WrapPropertyDescriptor).
+  cx->check(descObj);
+  if (!ToPropertyDescriptor(cx, descObj, true, desc)) {
+    return false;
+  }
+  CompletePropertyDescriptor(desc);
+  return true;
+}
+
+JS_PUBLIC_API void JS_SetAllNonReservedSlotsToUndefined(JS::HandleObject obj) {
+  if (!obj->is<NativeObject>()) {
+    return;
+  }
+
+  const JSClass* clasp = obj->getClass();
+  unsigned numReserved = JSCLASS_RESERVED_SLOTS(clasp);
+  unsigned numSlots = obj->as<NativeObject>().slotSpan();
+  for (unsigned i = numReserved; i < numSlots; i++) {
+    obj->as<NativeObject>().setSlot(i, UndefinedValue());
+  }
+}
+
+JS_PUBLIC_API void JS_SetReservedSlot(JSObject* obj, uint32_t index,
+                                      const Value& value) {
+  // Note: we don't use setReservedSlot so that this also works on swappable DOM
+  // objects. See NativeObject::getReservedSlotRef comment.
+  MOZ_ASSERT(index < JSCLASS_RESERVED_SLOTS(obj->getClass()));
+  obj->as<NativeObject>().setSlot(index, value);
+}
+
+JS_PUBLIC_API void JS_InitReservedSlot(JSObject* obj, uint32_t index, void* ptr,
+                                       size_t nbytes, JS::MemoryUse use) {
+  // Note: we don't use InitReservedSlot so that this also works on swappable
+  // DOM objects. See NativeObject::getReservedSlotRef comment.
+  MOZ_ASSERT(index < JSCLASS_RESERVED_SLOTS(obj->getClass()));
+  AddCellMemory(obj, nbytes, js::MemoryUse(use));
+  obj->as<NativeObject>().initSlot(index, PrivateValue(ptr));
+}
+
+JS_PUBLIC_API bool JS::IsMapObject(JSContext* cx, JS::HandleObject obj,
+                                   bool* isMap) {
+  return IsGivenTypeObject(cx, obj, ESClass::Map, isMap);
+}
+
+JS_PUBLIC_API bool JS::IsSetObject(JSContext* cx, JS::HandleObject obj,
+                                   bool* isSet) {
+  return IsGivenTypeObject(cx, obj, ESClass::Set, isSet);
+}
+
+JS_PUBLIC_API void JS_HoldPrincipals(JSPrincipals* principals) {
+  ++principals->refcount;
+}
+
+JS_PUBLIC_API void JS_DropPrincipals(JSContext* cx, JSPrincipals* principals) {
+  int rc = --principals->refcount;
+  if (rc == 0) {
+    JS::AutoSuppressGCAnalysis nogc;
+    cx->runtime()->destroyPrincipals(principals);
+  }
+}
+
+JS_PUBLIC_API void JS_SetSecurityCallbacks(JSContext* cx,
+                                           const JSSecurityCallbacks* scb) {
+  MOZ_ASSERT(scb != &NullSecurityCallbacks);
+  cx->runtime()->securityCallbacks = scb ? scb : &NullSecurityCallbacks;
+}
+
+JS_PUBLIC_API const JSSecurityCallbacks* JS_GetSecurityCallbacks(
+    JSContext* cx) {
+  return (cx->runtime()->securityCallbacks != &NullSecurityCallbacks)
+             ? cx->runtime()->securityCallbacks.ref()
+             : nullptr;
+}
+
+JS_PUBLIC_API void JS_SetTrustedPrincipals(JSContext* cx, JSPrincipals* prin) {
+  cx->runtime()->setTrustedPrincipals(prin);
+}
+
+extern JS_PUBLIC_API void JS_InitDestroyPrincipalsCallback(
+    JSContext* cx, JSDestroyPrincipalsOp destroyPrincipals) {
+  MOZ_ASSERT(destroyPrincipals);
+  MOZ_ASSERT(!cx->runtime()->destroyPrincipals);
+  cx->runtime()->destroyPrincipals = destroyPrincipals;
+}
+
+extern JS_PUBLIC_API void JS_InitReadPrincipalsCallback(
+    JSContext* cx, JSReadPrincipalsOp read) {
+  MOZ_ASSERT(read);
+  MOZ_ASSERT(!cx->runtime()->readPrincipals);
+  cx->runtime()->readPrincipals = read;
+}
+
+JS_PUBLIC_API JSFunction* JS_NewFunction(JSContext* cx, JSNative native,
+                                         unsigned nargs, unsigned flags,
+                                         const char* name) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  Rooted<JSAtom*> atom(cx);
+  if (name) {
+    atom = Atomize(cx, name, strlen(name));
+    if (!atom) {
+      return nullptr;
+    }
+  }
+
+  return (flags & JSFUN_CONSTRUCTOR)
+             ? NewNativeConstructor(cx, native, nargs, atom)
+             : NewNativeFunction(cx, native, nargs, atom);
+}
+
+JS_PUBLIC_API JSFunction* JS::GetSelfHostedFunction(JSContext* cx,
+                                                    const char* selfHostedName,
+                                                    HandleId id,
+                                                    unsigned nargs) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(id);
+
+  Rooted<JSAtom*> name(cx, IdToFunctionName(cx, id));
+  if (!name) {
+    return nullptr;
+  }
+
+  JSAtom* shAtom = Atomize(cx, selfHostedName, strlen(selfHostedName));
+  if (!shAtom) {
+    return nullptr;
+  }
+  Rooted<PropertyName*> shName(cx, shAtom->asPropertyName());
+  RootedValue funVal(cx);
+  if (!GlobalObject::getSelfHostedFunction(cx, cx->global(), shName, name,
+                                           nargs, &funVal)) {
+    return nullptr;
+  }
+  return &funVal.toObject().as<JSFunction>();
+}
+
+JS_PUBLIC_API JSFunction* JS::NewFunctionFromSpec(JSContext* cx,
+                                                  const JSFunctionSpec* fs,
+                                                  HandleId id) {
+  cx->check(id);
+
+#ifdef DEBUG
+  if (fs->name.isSymbol()) {
+    JS::Symbol* sym = cx->wellKnownSymbols().get(fs->name.symbol());
+    MOZ_ASSERT(PropertyKey::Symbol(sym) == id);
+  } else {
+    MOZ_ASSERT(id.isString() &&
+               StringEqualsAscii(id.toLinearString(), fs->name.string()));
+  }
+#endif
+
+  // Delay cloning self-hosted functions until they are called. This is
+  // achieved by passing DefineFunction a nullptr JSNative which produces an
+  // interpreted JSFunction where !hasScript. Interpreted call paths then
+  // call InitializeLazyFunctionScript if !hasScript.
+  if (fs->selfHostedName) {
+    MOZ_ASSERT(!fs->call.op);
+    MOZ_ASSERT(!fs->call.info);
+
+    JSAtom* shAtom =
+        Atomize(cx, fs->selfHostedName, strlen(fs->selfHostedName));
+    if (!shAtom) {
+      return nullptr;
+    }
+    Rooted<PropertyName*> shName(cx, shAtom->asPropertyName());
+    Rooted<JSAtom*> name(cx, IdToFunctionName(cx, id));
+    if (!name) {
+      return nullptr;
+    }
+    RootedValue funVal(cx);
+    if (!GlobalObject::getSelfHostedFunction(cx, cx->global(), shName, name,
+                                             fs->nargs, &funVal)) {
+      return nullptr;
+    }
+    return &funVal.toObject().as<JSFunction>();
+  }
+
+  Rooted<JSAtom*> atom(cx, IdToFunctionName(cx, id));
+  if (!atom) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(fs->call.op);
+
+  JSFunction* fun;
+  if (fs->flags & JSFUN_CONSTRUCTOR) {
+    fun = NewNativeConstructor(cx, fs->call.op, fs->nargs, atom);
+  } else {
+    fun = NewNativeFunction(cx, fs->call.op, fs->nargs, atom);
+  }
+  if (!fun) {
+    return nullptr;
+  }
+
+  if (fs->call.info) {
+    fun->setJitInfo(fs->call.info);
+  }
+  return fun;
+}
+
+JS_PUBLIC_API JSFunction* JS::NewFunctionFromSpec(JSContext* cx,
+                                                  const JSFunctionSpec* fs) {
+  RootedId id(cx);
+  if (!PropertySpecNameToId(cx, fs->name, &id)) {
+    return nullptr;
+  }
+
+  return NewFunctionFromSpec(cx, fs, id);
+}
+
+JS_PUBLIC_API JSObject* JS_GetFunctionObject(JSFunction* fun) { return fun; }
+
+JS_PUBLIC_API JSString* JS_GetFunctionId(JSFunction* fun) {
+  return fun->explicitName();
+}
+
+JS_PUBLIC_API JSString* JS_GetFunctionDisplayId(JSFunction* fun) {
+  return fun->displayAtom();
+}
+
+JS_PUBLIC_API uint16_t JS_GetFunctionArity(JSFunction* fun) {
+  return fun->nargs();
+}
+
+JS_PUBLIC_API bool JS_GetFunctionLength(JSContext* cx, HandleFunction fun,
+                                        uint16_t* length) {
+  cx->check(fun);
+  return JSFunction::getLength(cx, fun, length);
+}
+
+JS_PUBLIC_API bool JS_ObjectIsFunction(JSObject* obj) {
+  return obj->is<JSFunction>();
+}
+
+JS_PUBLIC_API bool JS_IsNativeFunction(JSObject* funobj, JSNative call) {
+  if (!funobj->is<JSFunction>()) {
+    return false;
+  }
+  JSFunction* fun = &funobj->as<JSFunction>();
+  return fun->isNativeFun() && fun->native() == call;
+}
+
+extern JS_PUBLIC_API bool JS_IsConstructor(JSFunction* fun) {
+  return fun->isConstructor();
+}
+
+void JS::TransitiveCompileOptions::copyPODTransitiveOptions(
+    const TransitiveCompileOptions& rhs) {
+  // filename_, introducerFilename_, sourceMapURL_ should be handled in caller.
+
+  mutedErrors_ = rhs.mutedErrors_;
+  forceStrictMode_ = rhs.forceStrictMode_;
+  shouldResistFingerprinting_ = rhs.shouldResistFingerprinting_;
+  sourcePragmas_ = rhs.sourcePragmas_;
+  skipFilenameValidation_ = rhs.skipFilenameValidation_;
+  hideScriptFromDebugger_ = rhs.hideScriptFromDebugger_;
+  deferDebugMetadata_ = rhs.deferDebugMetadata_;
+  eagerDelazificationStrategy_ = rhs.eagerDelazificationStrategy_;
+
+  selfHostingMode = rhs.selfHostingMode;
+  asmJSOption = rhs.asmJSOption;
+  throwOnAsmJSValidationFailureOption = rhs.throwOnAsmJSValidationFailureOption;
+  forceAsync = rhs.forceAsync;
+  discardSource = rhs.discardSource;
+  sourceIsLazy = rhs.sourceIsLazy;
+  allowHTMLComments = rhs.allowHTMLComments;
+  nonSyntacticScope = rhs.nonSyntacticScope;
+
+  topLevelAwait = rhs.topLevelAwait;
+  importAssertions = rhs.importAssertions;
+
+  borrowBuffer = rhs.borrowBuffer;
+  usePinnedBytecode = rhs.usePinnedBytecode;
+  allocateInstantiationStorage = rhs.allocateInstantiationStorage;
+  deoptimizeModuleGlobalVars = rhs.deoptimizeModuleGlobalVars;
+
+  introductionType = rhs.introductionType;
+  introductionLineno = rhs.introductionLineno;
+  introductionOffset = rhs.introductionOffset;
+  hasIntroductionInfo = rhs.hasIntroductionInfo;
+};
+
+void JS::ReadOnlyCompileOptions::copyPODNonTransitiveOptions(
+    const ReadOnlyCompileOptions& rhs) {
+  lineno = rhs.lineno;
+  column = rhs.column;
+  scriptSourceOffset = rhs.scriptSourceOffset;
+  isRunOnce = rhs.isRunOnce;
+  noScriptRval = rhs.noScriptRval;
+}
+
+JS::OwningCompileOptions::OwningCompileOptions(JSContext* cx)
+    : ReadOnlyCompileOptions() {}
+
+void JS::OwningCompileOptions::release() {
+  // OwningCompileOptions always owns these, so these casts are okay.
+  js_free(const_cast<char*>(filename_));
+  js_free(const_cast<char16_t*>(sourceMapURL_));
+  js_free(const_cast<char*>(introducerFilename_));
+
+  filename_ = nullptr;
+  sourceMapURL_ = nullptr;
+  introducerFilename_ = nullptr;
+}
+
+JS::OwningCompileOptions::~OwningCompileOptions() { release(); }
+
+size_t JS::OwningCompileOptions::sizeOfExcludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  return mallocSizeOf(filename_) + mallocSizeOf(sourceMapURL_) +
+         mallocSizeOf(introducerFilename_);
+}
+
+bool JS::OwningCompileOptions::copy(JSContext* cx,
+                                    const ReadOnlyCompileOptions& rhs) {
+  // Release existing string allocations.
+  release();
+
+  copyPODNonTransitiveOptions(rhs);
+  copyPODTransitiveOptions(rhs);
+
+  if (rhs.filename()) {
+    filename_ = DuplicateString(cx, rhs.filename()).release();
+    if (!filename_) {
+      return false;
+    }
+  }
+
+  if (rhs.sourceMapURL()) {
+    sourceMapURL_ = DuplicateString(cx, rhs.sourceMapURL()).release();
+    if (!sourceMapURL_) {
+      return false;
+    }
+  }
+
+  if (rhs.introducerFilename()) {
+    introducerFilename_ =
+        DuplicateString(cx, rhs.introducerFilename()).release();
+    if (!introducerFilename_) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+JS::CompileOptions::CompileOptions(JSContext* cx) : ReadOnlyCompileOptions() {
+  if (!js::IsAsmJSCompilationAvailable(cx)) {
+    // Distinguishing the cases is just for error reporting.
+    asmJSOption = !cx->options().asmJS()
+                      ? AsmJSOption::DisabledByAsmJSPref
+                      : AsmJSOption::DisabledByNoWasmCompiler;
+  } else if (cx->realm() && (cx->realm()->debuggerObservesWasm() ||
+                             cx->realm()->debuggerObservesAsmJS())) {
+    asmJSOption = AsmJSOption::DisabledByDebugger;
+  } else {
+    asmJSOption = AsmJSOption::Enabled;
+  }
+  throwOnAsmJSValidationFailureOption =
+      cx->options().throwOnAsmJSValidationFailure();
+
+  importAssertions = cx->options().importAssertions();
+
+  sourcePragmas_ = cx->options().sourcePragmas();
+
+  // Certain modes of operation force strict-mode in general.
+  forceStrictMode_ = cx->options().strictMode();
+
+  // Certain modes of operation disallow syntax parsing in general.
+  if (coverage::IsLCovEnabled()) {
+    eagerDelazificationStrategy_ = DelazificationOption::ParseEverythingEagerly;
+  }
+
+  // Note: If we parse outside of a specific realm, we do not inherit any realm
+  // behaviours. These can still be set manually on the options though.
+  if (Realm* realm = cx->realm()) {
+    shouldResistFingerprinting_ =
+        realm->behaviors().shouldResistFingerprinting();
+    discardSource = realm->behaviors().discardSource();
+  }
+}
+
+CompileOptions& CompileOptions::setIntroductionInfoToCaller(
+    JSContext* cx, const char* introductionType,
+    MutableHandle<JSScript*> introductionScript) {
+  RootedScript maybeScript(cx);
+  const char* filename;
+  unsigned lineno;
+  uint32_t pcOffset;
+  bool mutedErrors;
+  DescribeScriptedCallerForCompilation(cx, &maybeScript, &filename, &lineno,
+                                       &pcOffset, &mutedErrors);
+  if (filename) {
+    introductionScript.set(maybeScript);
+    return setIntroductionInfo(filename, introductionType, lineno, pcOffset);
+  }
+  return setIntroductionType(introductionType);
+}
+
+JS_PUBLIC_API JSObject* JS_GetGlobalFromScript(JSScript* script) {
+  return &script->global();
+}
+
+JS_PUBLIC_API const char* JS_GetScriptFilename(JSScript* script) {
+  // This is called from ThreadStackHelper which can be called from another
+  // thread or inside a signal hander, so we need to be careful in case a
+  // copmacting GC is currently moving things around.
+  return script->maybeForwardedFilename();
+}
+
+JS_PUBLIC_API unsigned JS_GetScriptBaseLineNumber(JSContext* cx,
+                                                  JSScript* script) {
+  return script->lineno();
+}
+
+JS_PUBLIC_API JSScript* JS_GetFunctionScript(JSContext* cx,
+                                             HandleFunction fun) {
+  if (fun->isNativeFun()) {
+    return nullptr;
+  }
+
+  if (fun->hasBytecode()) {
+    return fun->nonLazyScript();
+  }
+
+  AutoRealm ar(cx, fun);
+  JSScript* script = JSFunction::getOrCreateScript(cx, fun);
+  if (!script) {
+    MOZ_CRASH();
+  }
+  return script;
+}
+
+JS_PUBLIC_API JSString* JS_DecompileScript(JSContext* cx, HandleScript script) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  RootedFunction fun(cx, script->function());
+  if (fun) {
+    return JS_DecompileFunction(cx, fun);
+  }
+  bool haveSource;
+  if (!ScriptSource::loadSource(cx, script->scriptSource(), &haveSource)) {
+    return nullptr;
+  }
+  return haveSource ? JSScript::sourceData(cx, script)
+                    : NewStringCopyZ<CanGC>(cx, "[no source]");
+}
+
+JS_PUBLIC_API JSString* JS_DecompileFunction(JSContext* cx,
+                                             HandleFunction fun) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(fun);
+  return FunctionToString(cx, fun, /* isToSource = */ false);
+}
+
+JS_PUBLIC_API void JS::SetScriptPrivate(JSScript* script,
+                                        const JS::Value& value) {
+  JSRuntime* rt = script->zone()->runtimeFromMainThread();
+  script->sourceObject()->setPrivate(rt, value);
+}
+
+JS_PUBLIC_API JS::Value JS::GetScriptPrivate(JSScript* script) {
+  return script->sourceObject()->getPrivate();
+}
+
+JS_PUBLIC_API JS::Value JS::GetScriptedCallerPrivate(JSContext* cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  NonBuiltinFrameIter iter(cx, cx->realm()->principals());
+  if (iter.done() || !iter.hasScript()) {
+    return UndefinedValue();
+  }
+
+  return iter.script()->sourceObject()->getPrivate();
+}
+
+JS_PUBLIC_API void JS::SetScriptPrivateReferenceHooks(
+    JSRuntime* rt, JS::ScriptPrivateReferenceHook addRefHook,
+    JS::ScriptPrivateReferenceHook releaseHook) {
+  AssertHeapIsIdle();
+  rt->scriptPrivateAddRefHook = addRefHook;
+  rt->scriptPrivateReleaseHook = releaseHook;
+}
+
+JS_PUBLIC_API void JS::SetWaitCallback(JSRuntime* rt,
+                                       BeforeWaitCallback beforeWait,
+                                       AfterWaitCallback afterWait,
+                                       size_t requiredMemory) {
+  MOZ_RELEASE_ASSERT(requiredMemory <= WAIT_CALLBACK_CLIENT_MAXMEM);
+  MOZ_RELEASE_ASSERT((beforeWait == nullptr) == (afterWait == nullptr));
+  rt->beforeWaitCallback = beforeWait;
+  rt->afterWaitCallback = afterWait;
+}
+
+JS_PUBLIC_API bool JS_CheckForInterrupt(JSContext* cx) {
+  return js::CheckForInterrupt(cx);
+}
+
+JS_PUBLIC_API bool JS_AddInterruptCallback(JSContext* cx,
+                                           JSInterruptCallback callback) {
+  return cx->interruptCallbacks().append(callback);
+}
+
+JS_PUBLIC_API bool JS_DisableInterruptCallback(JSContext* cx) {
+  bool result = cx->interruptCallbackDisabled;
+  cx->interruptCallbackDisabled = true;
+  return result;
+}
+
+JS_PUBLIC_API void JS_ResetInterruptCallback(JSContext* cx, bool enable) {
+  cx->interruptCallbackDisabled = enable;
+}
+
+/************************************************************************/
+
+/*
+ * Promises.
+ */
+JS_PUBLIC_API void JS::SetJobQueue(JSContext* cx, JobQueue* queue) {
+  cx->jobQueue = queue;
+}
+
+extern JS_PUBLIC_API void JS::SetPromiseRejectionTrackerCallback(
+    JSContext* cx, PromiseRejectionTrackerCallback callback,
+    void* data /* = nullptr */) {
+  cx->promiseRejectionTrackerCallback = callback;
+  cx->promiseRejectionTrackerCallbackData = data;
+}
+
+extern JS_PUBLIC_API void JS::JobQueueIsEmpty(JSContext* cx) {
+  cx->canSkipEnqueuingJobs = true;
+}
+
+extern JS_PUBLIC_API void JS::JobQueueMayNotBeEmpty(JSContext* cx) {
+  cx->canSkipEnqueuingJobs = false;
+}
+
+JS_PUBLIC_API JSObject* JS::NewPromiseObject(JSContext* cx,
+                                             HandleObject executor) {
+  MOZ_ASSERT(!cx->zone()->isAtomsZone());
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(executor);
+
+  if (!executor) {
+    return PromiseObject::createSkippingExecutor(cx);
+  }
+
+  MOZ_ASSERT(IsCallable(executor));
+  return PromiseObject::create(cx, executor);
+}
+
+JS_PUBLIC_API bool JS::IsPromiseObject(JS::HandleObject obj) {
+  return obj->is<PromiseObject>();
+}
+
+JS_PUBLIC_API JSObject* JS::GetPromiseConstructor(JSContext* cx) {
+  CHECK_THREAD(cx);
+  Rooted<GlobalObject*> global(cx, cx->global());
+  return GlobalObject::getOrCreatePromiseConstructor(cx, global);
+}
+
+JS_PUBLIC_API JSObject* JS::GetPromisePrototype(JSContext* cx) {
+  CHECK_THREAD(cx);
+  Rooted<GlobalObject*> global(cx, cx->global());
+  return GlobalObject::getOrCreatePromisePrototype(cx, global);
+}
+
+JS_PUBLIC_API JS::PromiseState JS::GetPromiseState(JS::HandleObject promise) {
+  PromiseObject* promiseObj = promise->maybeUnwrapIf<PromiseObject>();
+  if (!promiseObj) {
+    return JS::PromiseState::Pending;
+  }
+
+  return promiseObj->state();
+}
+
+JS_PUBLIC_API uint64_t JS::GetPromiseID(JS::HandleObject promise) {
+  return promise->as<PromiseObject>().getID();
+}
+
+JS_PUBLIC_API JS::Value JS::GetPromiseResult(JS::HandleObject promiseObj) {
+  PromiseObject* promise = &promiseObj->as<PromiseObject>();
+  MOZ_ASSERT(promise->state() != JS::PromiseState::Pending);
+  return promise->state() == JS::PromiseState::Fulfilled ? promise->value()
+                                                         : promise->reason();
+}
+
+JS_PUBLIC_API bool JS::GetPromiseIsHandled(JS::HandleObject promise) {
+  PromiseObject* promiseObj = &promise->as<PromiseObject>();
+  return !promiseObj->isUnhandled();
+}
+
+static PromiseObject* UnwrapPromise(JSContext* cx, JS::HandleObject promise,
+                                    mozilla::Maybe<AutoRealm>& ar) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(promise);
+
+  PromiseObject* promiseObj;
+  if (IsWrapper(promise)) {
+    promiseObj = promise->maybeUnwrapAs<PromiseObject>();
+    if (!promiseObj) {
+      ReportAccessDenied(cx);
+      return nullptr;
+    }
+    ar.emplace(cx, promiseObj);
+  } else {
+    promiseObj = promise.as<PromiseObject>();
+  }
+  return promiseObj;
+}
+
+JS_PUBLIC_API bool JS::SetSettledPromiseIsHandled(JSContext* cx,
+                                                  JS::HandleObject promise) {
+  mozilla::Maybe<AutoRealm> ar;
+  Rooted<PromiseObject*> promiseObj(cx, UnwrapPromise(cx, promise, ar));
+  if (!promiseObj) {
+    return false;
+  }
+  js::SetSettledPromiseIsHandled(cx, promiseObj);
+  return true;
+}
+
+JS_PUBLIC_API bool JS::SetAnyPromiseIsHandled(JSContext* cx,
+                                              JS::HandleObject promise) {
+  mozilla::Maybe<AutoRealm> ar;
+  Rooted<PromiseObject*> promiseObj(cx, UnwrapPromise(cx, promise, ar));
+  if (!promiseObj) {
+    return false;
+  }
+  js::SetAnyPromiseIsHandled(cx, promiseObj);
+  return true;
+}
+
+JS_PUBLIC_API JSObject* JS::GetPromiseAllocationSite(JS::HandleObject promise) {
+  return promise->as<PromiseObject>().allocationSite();
+}
+
+JS_PUBLIC_API JSObject* JS::GetPromiseResolutionSite(JS::HandleObject promise) {
+  return promise->as<PromiseObject>().resolutionSite();
+}
+
+#ifdef DEBUG
+JS_PUBLIC_API void JS::DumpPromiseAllocationSite(JSContext* cx,
+                                                 JS::HandleObject promise) {
+  RootedObject stack(cx, promise->as<PromiseObject>().allocationSite());
+  JSPrincipals* principals = cx->realm()->principals();
+  UniqueChars stackStr = BuildUTF8StackString(cx, principals, stack);
+  if (stackStr) {
+    fputs(stackStr.get(), stderr);
+  }
+}
+
+JS_PUBLIC_API void JS::DumpPromiseResolutionSite(JSContext* cx,
+                                                 JS::HandleObject promise) {
+  RootedObject stack(cx, promise->as<PromiseObject>().resolutionSite());
+  JSPrincipals* principals = cx->realm()->principals();
+  UniqueChars stackStr = BuildUTF8StackString(cx, principals, stack);
+  if (stackStr) {
+    fputs(stackStr.get(), stderr);
+  }
+}
+#endif
+
+JS_PUBLIC_API JSObject* JS::CallOriginalPromiseResolve(
+    JSContext* cx, JS::HandleValue resolutionValue) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(resolutionValue);
+
+  RootedObject promise(cx,
+                       PromiseObject::unforgeableResolve(cx, resolutionValue));
+  MOZ_ASSERT_IF(promise, promise->canUnwrapAs<PromiseObject>());
+  return promise;
+}
+
+JS_PUBLIC_API JSObject* JS::CallOriginalPromiseReject(
+    JSContext* cx, JS::HandleValue rejectionValue) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(rejectionValue);
+
+  RootedObject promise(cx,
+                       PromiseObject::unforgeableReject(cx, rejectionValue));
+  MOZ_ASSERT_IF(promise, promise->canUnwrapAs<PromiseObject>());
+  return promise;
+}
+
+static bool ResolveOrRejectPromise(JSContext* cx, JS::HandleObject promiseObj,
+                                   JS::HandleValue resultOrReason_,
+                                   bool reject) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(promiseObj, resultOrReason_);
+
+  mozilla::Maybe<AutoRealm> ar;
+  Rooted<PromiseObject*> promise(cx);
+  RootedValue resultOrReason(cx, resultOrReason_);
+  if (IsWrapper(promiseObj)) {
+    promise = promiseObj->maybeUnwrapAs<PromiseObject>();
+    if (!promise) {
+      ReportAccessDenied(cx);
+      return false;
+    }
+    ar.emplace(cx, promise);
+    if (!cx->compartment()->wrap(cx, &resultOrReason)) {
+      return false;
+    }
+  } else {
+    promise = promiseObj.as<PromiseObject>();
+  }
+
+  return reject ? PromiseObject::reject(cx, promise, resultOrReason)
+                : PromiseObject::resolve(cx, promise, resultOrReason);
+}
+
+JS_PUBLIC_API bool JS::ResolvePromise(JSContext* cx,
+                                      JS::HandleObject promiseObj,
+                                      JS::HandleValue resolutionValue) {
+  return ResolveOrRejectPromise(cx, promiseObj, resolutionValue, false);
+}
+
+JS_PUBLIC_API bool JS::RejectPromise(JSContext* cx, JS::HandleObject promiseObj,
+                                     JS::HandleValue rejectionValue) {
+  return ResolveOrRejectPromise(cx, promiseObj, rejectionValue, true);
+}
+
+JS_PUBLIC_API JSObject* JS::CallOriginalPromiseThen(
+    JSContext* cx, JS::HandleObject promiseObj, JS::HandleObject onFulfilled,
+    JS::HandleObject onRejected) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(promiseObj, onFulfilled, onRejected);
+
+  MOZ_ASSERT_IF(onFulfilled, IsCallable(onFulfilled));
+  MOZ_ASSERT_IF(onRejected, IsCallable(onRejected));
+
+  return OriginalPromiseThen(cx, promiseObj, onFulfilled, onRejected);
+}
+
+[[nodiscard]] static bool ReactToPromise(JSContext* cx,
+                                         JS::Handle<JSObject*> promiseObj,
+                                         JS::Handle<JSObject*> onFulfilled,
+                                         JS::Handle<JSObject*> onRejected,
+                                         UnhandledRejectionBehavior behavior) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(promiseObj, onFulfilled, onRejected);
+
+  MOZ_ASSERT_IF(onFulfilled, IsCallable(onFulfilled));
+  MOZ_ASSERT_IF(onRejected, IsCallable(onRejected));
+
+  Rooted<PromiseObject*> unwrappedPromise(cx);
+  {
+    RootedValue promiseVal(cx, ObjectValue(*promiseObj));
+    unwrappedPromise = UnwrapAndTypeCheckValue<PromiseObject>(
+        cx, promiseVal, [cx, promiseObj] {
+          JS_ReportErrorNumberLatin1(cx, GetErrorMessage, nullptr,
+                                     JSMSG_INCOMPATIBLE_PROTO, "Promise",
+                                     "then", promiseObj->getClass()->name);
+        });
+    if (!unwrappedPromise) {
+      return false;
+    }
+  }
+
+  return ReactToUnwrappedPromise(cx, unwrappedPromise, onFulfilled, onRejected,
+                                 behavior);
+}
+
+JS_PUBLIC_API bool JS::AddPromiseReactions(JSContext* cx,
+                                           JS::HandleObject promiseObj,
+                                           JS::HandleObject onFulfilled,
+                                           JS::HandleObject onRejected) {
+  return ReactToPromise(cx, promiseObj, onFulfilled, onRejected,
+                        UnhandledRejectionBehavior::Report);
+}
+
+JS_PUBLIC_API bool JS::AddPromiseReactionsIgnoringUnhandledRejection(
+    JSContext* cx, JS::HandleObject promiseObj, JS::HandleObject onFulfilled,
+    JS::HandleObject onRejected) {
+  return ReactToPromise(cx, promiseObj, onFulfilled, onRejected,
+                        UnhandledRejectionBehavior::Ignore);
+}
+
+JS_PUBLIC_API JS::PromiseUserInputEventHandlingState
+JS::GetPromiseUserInputEventHandlingState(JS::HandleObject promiseObj_) {
+  PromiseObject* promise = promiseObj_->maybeUnwrapIf<PromiseObject>();
+  if (!promise) {
+    return JS::PromiseUserInputEventHandlingState::DontCare;
+  }
+
+  if (!promise->requiresUserInteractionHandling()) {
+    return JS::PromiseUserInputEventHandlingState::DontCare;
+  }
+  if (promise->hadUserInteractionUponCreation()) {
+    return JS::PromiseUserInputEventHandlingState::HadUserInteractionAtCreation;
+  }
+  return JS::PromiseUserInputEventHandlingState::
+      DidntHaveUserInteractionAtCreation;
+}
+
+JS_PUBLIC_API bool JS::SetPromiseUserInputEventHandlingState(
+    JS::HandleObject promiseObj_,
+    JS::PromiseUserInputEventHandlingState state) {
+  PromiseObject* promise = promiseObj_->maybeUnwrapIf<PromiseObject>();
+  if (!promise) {
+    return false;
+  }
+
+  switch (state) {
+    case JS::PromiseUserInputEventHandlingState::DontCare:
+      promise->setRequiresUserInteractionHandling(false);
+      break;
+    case JS::PromiseUserInputEventHandlingState::HadUserInteractionAtCreation:
+      promise->setRequiresUserInteractionHandling(true);
+      promise->setHadUserInteractionUponCreation(true);
+      break;
+    case JS::PromiseUserInputEventHandlingState::
+        DidntHaveUserInteractionAtCreation:
+      promise->setRequiresUserInteractionHandling(true);
+      promise->setHadUserInteractionUponCreation(false);
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE(
+          "Invalid PromiseUserInputEventHandlingState enum value");
+      return false;
+  }
+  return true;
+}
+
+/**
+ * Unforgeable version of Promise.all for internal use.
+ *
+ * Takes a dense array of Promise objects and returns a promise that's
+ * resolved with an array of resolution values when all those promises ahve
+ * been resolved, or rejected with the rejection value of the first rejected
+ * promise.
+ *
+ * Asserts that the array is dense and all entries are Promise objects.
+ */
+JS_PUBLIC_API JSObject* JS::GetWaitForAllPromise(
+    JSContext* cx, JS::HandleObjectVector promises) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return js::GetWaitForAllPromise(cx, promises);
+}
+
+JS_PUBLIC_API void JS::InitDispatchToEventLoop(
+    JSContext* cx, JS::DispatchToEventLoopCallback callback, void* closure) {
+  cx->runtime()->offThreadPromiseState.ref().init(callback, closure);
+}
+
+JS_PUBLIC_API void JS::ShutdownAsyncTasks(JSContext* cx) {
+  cx->runtime()->offThreadPromiseState.ref().shutdown(cx);
+}
+
+JS_PUBLIC_API void JS::InitConsumeStreamCallback(
+    JSContext* cx, ConsumeStreamCallback consume,
+    ReportStreamErrorCallback report) {
+  cx->runtime()->consumeStreamCallback = consume;
+  cx->runtime()->reportStreamErrorCallback = report;
+}
+
+JS_PUBLIC_API void JS_RequestInterruptCallback(JSContext* cx) {
+  cx->requestInterrupt(InterruptReason::CallbackUrgent);
+}
+
+JS_PUBLIC_API void JS_RequestInterruptCallbackCanWait(JSContext* cx) {
+  cx->requestInterrupt(InterruptReason::CallbackCanWait);
+}
+
+JS::AutoSetAsyncStackForNewCalls::AutoSetAsyncStackForNewCalls(
+    JSContext* cx, HandleObject stack, const char* asyncCause,
+    JS::AutoSetAsyncStackForNewCalls::AsyncCallKind kind)
+    : cx(cx),
+      oldAsyncStack(cx, cx->asyncStackForNewActivations()),
+      oldAsyncCause(cx->asyncCauseForNewActivations),
+      oldAsyncCallIsExplicit(cx->asyncCallIsExplicit) {
+  CHECK_THREAD(cx);
+
+  // The option determines whether we actually use the new values at this
+  // point. It will not affect restoring the previous values when the object
+  // is destroyed, so if the option changes it won't cause consistency issues.
+  if (!cx->options().asyncStack()) {
+    return;
+  }
+
+  SavedFrame* asyncStack = &stack->as<SavedFrame>();
+
+  cx->asyncStackForNewActivations() = asyncStack;
+  cx->asyncCauseForNewActivations = asyncCause;
+  cx->asyncCallIsExplicit = kind == AsyncCallKind::EXPLICIT;
+}
+
+JS::AutoSetAsyncStackForNewCalls::~AutoSetAsyncStackForNewCalls() {
+  cx->asyncCauseForNewActivations = oldAsyncCause;
+  cx->asyncStackForNewActivations() =
+      oldAsyncStack ? &oldAsyncStack->as<SavedFrame>() : nullptr;
+  cx->asyncCallIsExplicit = oldAsyncCallIsExplicit;
+}
+
+/************************************************************************/
+JS_PUBLIC_API JSString* JS_NewStringCopyN(JSContext* cx, const char* s,
+                                          size_t n) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewStringCopyN<CanGC>(cx, s, n);
+}
+
+JS_PUBLIC_API JSString* JS_NewStringCopyZ(JSContext* cx, const char* s) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (!s) {
+    return cx->runtime()->emptyString;
+  }
+  return NewStringCopyZ<CanGC>(cx, s);
+}
+
+JS_PUBLIC_API JSString* JS_NewStringCopyUTF8Z(JSContext* cx,
+                                              const JS::ConstUTF8CharsZ s) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewStringCopyUTF8Z(cx, s);
+}
+
+JS_PUBLIC_API JSString* JS_NewStringCopyUTF8N(JSContext* cx,
+                                              const JS::UTF8Chars s) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewStringCopyUTF8N(cx, s);
+}
+
+JS_PUBLIC_API bool JS_StringHasBeenPinned(JSContext* cx, JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (!str->isAtom()) {
+    return false;
+  }
+
+  return AtomIsPinned(cx, &str->asAtom());
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeString(JSContext* cx, const char* s) {
+  return JS_AtomizeStringN(cx, s, strlen(s));
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeStringN(JSContext* cx, const char* s,
+                                          size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return Atomize(cx, s, length);
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeAndPinString(JSContext* cx, const char* s) {
+  return JS_AtomizeAndPinStringN(cx, s, strlen(s));
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeAndPinStringN(JSContext* cx, const char* s,
+                                                size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  JSAtom* atom = cx->zone() ? Atomize(cx, s, length)
+                            : AtomizeWithoutActiveZone(cx, s, length);
+  if (!atom || !PinAtom(cx, atom)) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(JS_StringHasBeenPinned(cx, atom));
+  return atom;
+}
+
+JS_PUBLIC_API JSString* JS_NewLatin1String(
+    JSContext* cx, js::UniquePtr<JS::Latin1Char[], JS::FreePolicy> chars,
+    size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewString<CanGC>(cx, std::move(chars), length);
+}
+
+JS_PUBLIC_API JSString* JS_NewUCString(JSContext* cx,
+                                       JS::UniqueTwoByteChars chars,
+                                       size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewString<CanGC>(cx, std::move(chars), length);
+}
+
+JS_PUBLIC_API JSString* JS_NewUCStringDontDeflate(JSContext* cx,
+                                                  JS::UniqueTwoByteChars chars,
+                                                  size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewStringDontDeflate<CanGC>(cx, std::move(chars), length);
+}
+
+JS_PUBLIC_API JSString* JS_NewUCStringCopyN(JSContext* cx, const char16_t* s,
+                                            size_t n) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (!n) {
+    return cx->names().empty;
+  }
+  return NewStringCopyN<CanGC>(cx, s, n);
+}
+
+JS_PUBLIC_API JSString* JS_NewUCStringCopyZ(JSContext* cx, const char16_t* s) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (!s) {
+    return cx->runtime()->emptyString;
+  }
+  return NewStringCopyZ<CanGC>(cx, s);
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeUCString(JSContext* cx, const char16_t* s) {
+  return JS_AtomizeUCStringN(cx, s, js_strlen(s));
+}
+
+JS_PUBLIC_API JSString* JS_AtomizeUCStringN(JSContext* cx, const char16_t* s,
+                                            size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return AtomizeChars(cx, s, length);
+}
+
+JS_PUBLIC_API size_t JS_GetStringLength(JSString* str) { return str->length(); }
+
+JS_PUBLIC_API bool JS_StringIsLinear(JSString* str) { return str->isLinear(); }
+
+JS_PUBLIC_API bool JS_DeprecatedStringHasLatin1Chars(JSString* str) {
+  return str->hasLatin1Chars();
+}
+
+JS_PUBLIC_API const JS::Latin1Char* JS_GetLatin1StringCharsAndLength(
+    JSContext* cx, const JS::AutoRequireNoGC& nogc, JSString* str,
+    size_t* plength) {
+  MOZ_ASSERT(plength);
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return nullptr;
+  }
+  *plength = linear->length();
+  return linear->latin1Chars(nogc);
+}
+
+JS_PUBLIC_API const char16_t* JS_GetTwoByteStringCharsAndLength(
+    JSContext* cx, const JS::AutoRequireNoGC& nogc, JSString* str,
+    size_t* plength) {
+  MOZ_ASSERT(plength);
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return nullptr;
+  }
+  *plength = linear->length();
+  return linear->twoByteChars(nogc);
+}
+
+JS_PUBLIC_API const char16_t* JS_GetTwoByteExternalStringChars(JSString* str) {
+  return str->asExternal().twoByteChars();
+}
+
+JS_PUBLIC_API bool JS_GetStringCharAt(JSContext* cx, JSString* str,
+                                      size_t index, char16_t* res) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return false;
+  }
+
+  *res = linear->latin1OrTwoByteChar(index);
+  return true;
+}
+
+JS_PUBLIC_API bool JS_CopyStringChars(JSContext* cx,
+                                      mozilla::Range<char16_t> dest,
+                                      JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return false;
+  }
+
+  MOZ_ASSERT(linear->length() <= dest.length());
+  CopyChars(dest.begin().get(), *linear);
+  return true;
+}
+
+extern JS_PUBLIC_API JS::UniqueTwoByteChars JS_CopyStringCharsZ(JSContext* cx,
+                                                                JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return nullptr;
+  }
+
+  size_t len = linear->length();
+
+  static_assert(JS::MaxStringLength < UINT32_MAX,
+                "len + 1 must not overflow on 32-bit platforms");
+
+  UniqueTwoByteChars chars(cx->pod_malloc<char16_t>(len + 1));
+  if (!chars) {
+    return nullptr;
+  }
+
+  CopyChars(chars.get(), *linear);
+  chars[len] = '\0';
+
+  return chars;
+}
+
+extern JS_PUBLIC_API JSLinearString* JS_EnsureLinearString(JSContext* cx,
+                                                           JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+  return str->ensureLinear(cx);
+}
+
+JS_PUBLIC_API bool JS_CompareStrings(JSContext* cx, JSString* str1,
+                                     JSString* str2, int32_t* result) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return CompareStrings(cx, str1, str2, result);
+}
+
+JS_PUBLIC_API bool JS_StringEqualsAscii(JSContext* cx, JSString* str,
+                                        const char* asciiBytes, bool* match) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  JSLinearString* linearStr = str->ensureLinear(cx);
+  if (!linearStr) {
+    return false;
+  }
+  *match = StringEqualsAscii(linearStr, asciiBytes);
+  return true;
+}
+
+JS_PUBLIC_API bool JS_StringEqualsAscii(JSContext* cx, JSString* str,
+                                        const char* asciiBytes, size_t length,
+                                        bool* match) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  JSLinearString* linearStr = str->ensureLinear(cx);
+  if (!linearStr) {
+    return false;
+  }
+  *match = StringEqualsAscii(linearStr, asciiBytes, length);
+  return true;
+}
+
+JS_PUBLIC_API bool JS_LinearStringEqualsAscii(JSLinearString* str,
+                                              const char* asciiBytes) {
+  return StringEqualsAscii(str, asciiBytes);
+}
+
+JS_PUBLIC_API bool JS_LinearStringEqualsAscii(JSLinearString* str,
+                                              const char* asciiBytes,
+                                              size_t length) {
+  return StringEqualsAscii(str, asciiBytes, length);
+}
+
+JS_PUBLIC_API size_t JS_PutEscapedLinearString(char* buffer, size_t size,
+                                               JSLinearString* str,
+                                               char quote) {
+  return PutEscapedString(buffer, size, str, quote);
+}
+
+JS_PUBLIC_API size_t JS_PutEscapedString(JSContext* cx, char* buffer,
+                                         size_t size, JSString* str,
+                                         char quote) {
+  AssertHeapIsIdle();
+  JSLinearString* linearStr = str->ensureLinear(cx);
+  if (!linearStr) {
+    return size_t(-1);
+  }
+  return PutEscapedString(buffer, size, linearStr, quote);
+}
+
+JS_PUBLIC_API JSString* JS_NewDependentString(JSContext* cx, HandleString str,
+                                              size_t start, size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return NewDependentString(cx, str, start, length);
+}
+
+JS_PUBLIC_API JSString* JS_ConcatStrings(JSContext* cx, HandleString left,
+                                         HandleString right) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return ConcatStrings<CanGC>(cx, left, right);
+}
+
+JS_PUBLIC_API bool JS_DecodeBytes(JSContext* cx, const char* src, size_t srclen,
+                                  char16_t* dst, size_t* dstlenp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (!dst) {
+    *dstlenp = srclen;
+    return true;
+  }
+
+  size_t dstlen = *dstlenp;
+
+  if (srclen > dstlen) {
+    CopyAndInflateChars(dst, src, dstlen);
+
+    gc::AutoSuppressGC suppress(cx);
+    JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                              JSMSG_BUFFER_TOO_SMALL);
+    return false;
+  }
+
+  CopyAndInflateChars(dst, src, srclen);
+  *dstlenp = srclen;
+  return true;
+}
+
+JS_PUBLIC_API JS::UniqueChars JS_EncodeStringToASCII(JSContext* cx,
+                                                     JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return js::EncodeAscii(cx, str);
+}
+
+JS_PUBLIC_API JS::UniqueChars JS_EncodeStringToLatin1(JSContext* cx,
+                                                      JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return js::EncodeLatin1(cx, str);
+}
+
+JS_PUBLIC_API JS::UniqueChars JS_EncodeStringToUTF8(JSContext* cx,
+                                                    HandleString str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  return StringToNewUTF8CharsZ(cx, *str);
+}
+
+JS_PUBLIC_API size_t JS_GetStringEncodingLength(JSContext* cx, JSString* str) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  if (!str->ensureLinear(cx)) {
+    return size_t(-1);
+  }
+  return str->length();
+}
+
+JS_PUBLIC_API bool JS_EncodeStringToBuffer(JSContext* cx, JSString* str,
+                                           char* buffer, size_t length) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+
+  JSLinearString* linear = str->ensureLinear(cx);
+  if (!linear) {
+    return false;
+  }
+
+  JS::AutoCheckCannotGC nogc;
+  size_t writeLength = std::min(linear->length(), length);
+  if (linear->hasLatin1Chars()) {
+    mozilla::PodCopy(reinterpret_cast<Latin1Char*>(buffer),
+                     linear->latin1Chars(nogc), writeLength);
+  } else {
+    const char16_t* src = linear->twoByteChars(nogc);
+    for (size_t i = 0; i < writeLength; i++) {
+      buffer[i] = char(src[i]);
+    }
+  }
+  return true;
+}
+
+JS_PUBLIC_API mozilla::Maybe<std::tuple<size_t, size_t>>
+JS_EncodeStringToUTF8BufferPartial(JSContext* cx, JSString* str,
+                                   mozilla::Span<char> buffer) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  JS::AutoCheckCannotGC nogc;
+  return str->encodeUTF8Partial(nogc, buffer);
+}
+
+JS_PUBLIC_API JS::Symbol* JS::NewSymbol(JSContext* cx,
+                                        HandleString description) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (description) {
+    cx->check(description);
+  }
+
+  return Symbol::new_(cx, SymbolCode::UniqueSymbol, description);
+}
+
+JS_PUBLIC_API JS::Symbol* JS::GetSymbolFor(JSContext* cx, HandleString key) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(key);
+
+  return Symbol::for_(cx, key);
+}
+
+JS_PUBLIC_API JSString* JS::GetSymbolDescription(HandleSymbol symbol) {
+  return symbol->description();
+}
+
+JS_PUBLIC_API JS::SymbolCode JS::GetSymbolCode(Handle<Symbol*> symbol) {
+  return symbol->code();
+}
+
+JS_PUBLIC_API JS::Symbol* JS::GetWellKnownSymbol(JSContext* cx,
+                                                 JS::SymbolCode which) {
+  return cx->wellKnownSymbols().get(which);
+}
+
+JS_PUBLIC_API JS::PropertyKey JS::GetWellKnownSymbolKey(JSContext* cx,
+                                                        JS::SymbolCode which) {
+  return PropertyKey::Symbol(cx->wellKnownSymbols().get(which));
+}
+
+static bool AddPrefix(JSContext* cx, JS::Handle<JS::PropertyKey> id,
+                      FunctionPrefixKind prefixKind,
+                      JS::MutableHandle<JS::PropertyKey> out) {
+  JS::Rooted<JSAtom*> atom(cx, js::IdToFunctionName(cx, id, prefixKind));
+  if (!atom) {
+    return false;
+  }
+
+  out.set(JS::PropertyKey::NonIntAtom(atom));
+  return true;
+}
+
+JS_PUBLIC_API bool JS::ToGetterId(JSContext* cx, JS::Handle<JS::PropertyKey> id,
+                                  JS::MutableHandle<JS::PropertyKey> getterId) {
+  return AddPrefix(cx, id, FunctionPrefixKind::Get, getterId);
+}
+
+JS_PUBLIC_API bool JS::ToSetterId(JSContext* cx, JS::Handle<JS::PropertyKey> id,
+                                  JS::MutableHandle<JS::PropertyKey> setterId) {
+  return AddPrefix(cx, id, FunctionPrefixKind::Set, setterId);
+}
+
+#ifdef DEBUG
+static bool PropertySpecNameIsDigits(JSPropertySpec::Name name) {
+  if (name.isSymbol()) {
+    return false;
+  }
+  const char* s = name.string();
+  if (!*s) {
+    return false;
+  }
+  for (; *s; s++) {
+    if (*s < '0' || *s > '9') {
+      return false;
+    }
+  }
+  return true;
+}
+#endif  // DEBUG
+
+JS_PUBLIC_API bool JS::PropertySpecNameEqualsId(JSPropertySpec::Name name,
+                                                HandleId id) {
+  if (name.isSymbol()) {
+    return id.isWellKnownSymbol(name.symbol());
+  }
+
+  MOZ_ASSERT(!PropertySpecNameIsDigits(name));
+  return id.isAtom() && JS_LinearStringEqualsAscii(id.toAtom(), name.string());
+}
+
+JS_PUBLIC_API bool JS_Stringify(JSContext* cx, MutableHandleValue vp,
+                                HandleObject replacer, HandleValue space,
+                                JSONWriteCallback callback, void* data) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(replacer, space);
+  StringBuffer sb(cx);
+  if (!sb.ensureTwoByteChars()) {
+    return false;
+  }
+  if (!Stringify(cx, vp, replacer, space, sb, StringifyBehavior::Normal)) {
+    return false;
+  }
+  if (sb.empty() && !sb.append(cx->names().null)) {
+    return false;
+  }
+  return callback(sb.rawTwoByteBegin(), sb.length(), data);
+}
+
+JS_PUBLIC_API bool JS::ToJSON(JSContext* cx, HandleValue value,
+                              HandleObject replacer, HandleValue space,
+                              JSONWriteCallback callback, void* data) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(replacer, space);
+  StringBuffer sb(cx);
+  if (!sb.ensureTwoByteChars()) {
+    return false;
+  }
+  RootedValue v(cx, value);
+  if (!Stringify(cx, &v, replacer, space, sb, StringifyBehavior::Normal)) {
+    return false;
+  }
+  if (sb.empty()) {
+    return true;
+  }
+  return callback(sb.rawTwoByteBegin(), sb.length(), data);
+}
+
+JS_PUBLIC_API bool JS::ToJSONMaybeSafely(JSContext* cx, JS::HandleObject input,
+                                         JSONWriteCallback callback,
+                                         void* data) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(input);
+
+  StringBuffer sb(cx);
+  if (!sb.ensureTwoByteChars()) {
+    return false;
+  }
+
+  RootedValue inputValue(cx, ObjectValue(*input));
+  if (!Stringify(cx, &inputValue, nullptr, NullHandleValue, sb,
+                 StringifyBehavior::RestrictedSafe))
+    return false;
+
+  if (sb.empty() && !sb.append(cx->names().null)) {
+    return false;
+  }
+
+  return callback(sb.rawTwoByteBegin(), sb.length(), data);
+}
+
+JS_PUBLIC_API bool JS_ParseJSON(JSContext* cx, const char16_t* chars,
+                                uint32_t len, MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return ParseJSONWithReviver(cx, mozilla::Range<const char16_t>(chars, len),
+                              NullHandleValue, vp);
+}
+
+JS_PUBLIC_API bool JS_ParseJSON(JSContext* cx, HandleString str,
+                                MutableHandleValue vp) {
+  return JS_ParseJSONWithReviver(cx, str, NullHandleValue, vp);
+}
+
+JS_PUBLIC_API bool JS_ParseJSON(JSContext* cx, const Latin1Char* chars,
+                                uint32_t len, MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return ParseJSONWithReviver(cx, mozilla::Range<const Latin1Char>(chars, len),
+                              NullHandleValue, vp);
+}
+
+JS_PUBLIC_API bool JS_ParseJSONWithReviver(JSContext* cx, const char16_t* chars,
+                                           uint32_t len, HandleValue reviver,
+                                           MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  return ParseJSONWithReviver(cx, mozilla::Range<const char16_t>(chars, len),
+                              reviver, vp);
+}
+
+JS_PUBLIC_API bool JS_ParseJSONWithReviver(JSContext* cx, HandleString str,
+                                           HandleValue reviver,
+                                           MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(str);
+
+  AutoStableStringChars stableChars(cx);
+  if (!stableChars.init(cx, str)) {
+    return false;
+  }
+
+  return stableChars.isLatin1()
+             ? ParseJSONWithReviver(cx, stableChars.latin1Range(), reviver, vp)
+             : ParseJSONWithReviver(cx, stableChars.twoByteRange(), reviver,
+                                    vp);
+}
+
+/************************************************************************/
+
+JS_PUBLIC_API void JS_ReportErrorASCII(JSContext* cx, const char* format, ...) {
+  va_list ap;
+
+  AssertHeapIsIdle();
+  va_start(ap, format);
+  ReportErrorVA(cx, IsWarning::No, format, ArgumentsAreASCII, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorLatin1(JSContext* cx, const char* format,
+                                        ...) {
+  va_list ap;
+
+  AssertHeapIsIdle();
+  va_start(ap, format);
+  ReportErrorVA(cx, IsWarning::No, format, ArgumentsAreLatin1, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorUTF8(JSContext* cx, const char* format, ...) {
+  va_list ap;
+
+  AssertHeapIsIdle();
+  va_start(ap, format);
+  ReportErrorVA(cx, IsWarning::No, format, ArgumentsAreUTF8, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberASCII(JSContext* cx,
+                                             JSErrorCallback errorCallback,
+                                             void* userRef,
+                                             const unsigned errorNumber, ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  JS_ReportErrorNumberASCIIVA(cx, errorCallback, userRef, errorNumber, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberASCIIVA(JSContext* cx,
+                                               JSErrorCallback errorCallback,
+                                               void* userRef,
+                                               const unsigned errorNumber,
+                                               va_list ap) {
+  AssertHeapIsIdle();
+  ReportErrorNumberVA(cx, IsWarning::No, errorCallback, userRef, errorNumber,
+                      ArgumentsAreASCII, ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberLatin1(JSContext* cx,
+                                              JSErrorCallback errorCallback,
+                                              void* userRef,
+                                              const unsigned errorNumber, ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  JS_ReportErrorNumberLatin1VA(cx, errorCallback, userRef, errorNumber, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberLatin1VA(JSContext* cx,
+                                                JSErrorCallback errorCallback,
+                                                void* userRef,
+                                                const unsigned errorNumber,
+                                                va_list ap) {
+  AssertHeapIsIdle();
+  ReportErrorNumberVA(cx, IsWarning::No, errorCallback, userRef, errorNumber,
+                      ArgumentsAreLatin1, ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberUTF8(JSContext* cx,
+                                            JSErrorCallback errorCallback,
+                                            void* userRef,
+                                            const unsigned errorNumber, ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  JS_ReportErrorNumberUTF8VA(cx, errorCallback, userRef, errorNumber, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberUTF8VA(JSContext* cx,
+                                              JSErrorCallback errorCallback,
+                                              void* userRef,
+                                              const unsigned errorNumber,
+                                              va_list ap) {
+  AssertHeapIsIdle();
+  ReportErrorNumberVA(cx, IsWarning::No, errorCallback, userRef, errorNumber,
+                      ArgumentsAreUTF8, ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberUTF8Array(JSContext* cx,
+                                                 JSErrorCallback errorCallback,
+                                                 void* userRef,
+                                                 const unsigned errorNumber,
+                                                 const char** args) {
+  AssertHeapIsIdle();
+  ReportErrorNumberUTF8Array(cx, IsWarning::No, errorCallback, userRef,
+                             errorNumber, args);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberUC(JSContext* cx,
+                                          JSErrorCallback errorCallback,
+                                          void* userRef,
+                                          const unsigned errorNumber, ...) {
+  va_list ap;
+
+  AssertHeapIsIdle();
+  va_start(ap, errorNumber);
+  ReportErrorNumberVA(cx, IsWarning::No, errorCallback, userRef, errorNumber,
+                      ArgumentsAreUnicode, ap);
+  va_end(ap);
+}
+
+JS_PUBLIC_API void JS_ReportErrorNumberUCArray(JSContext* cx,
+                                               JSErrorCallback errorCallback,
+                                               void* userRef,
+                                               const unsigned errorNumber,
+                                               const char16_t** args) {
+  AssertHeapIsIdle();
+  ReportErrorNumberUCArray(cx, IsWarning::No, errorCallback, userRef,
+                           errorNumber, args);
+}
+
+JS_PUBLIC_API void JS_ReportOutOfMemory(JSContext* cx) {
+  ReportOutOfMemory(cx);
+}
+
+JS_PUBLIC_API void JS_ReportAllocationOverflow(JSContext* cx) {
+  ReportAllocationOverflow(cx);
+}
+
+JS_PUBLIC_API bool JS_ExpandErrorArgumentsASCII(JSContext* cx,
+                                                JSErrorCallback errorCallback,
+                                                const unsigned errorNumber,
+                                                JSErrorReport* reportp, ...) {
+  va_list ap;
+  bool ok;
+
+  AssertHeapIsIdle();
+  va_start(ap, reportp);
+  AutoReportFrontendContext fc(cx);
+  ok = ExpandErrorArgumentsVA(&fc, errorCallback, nullptr, errorNumber,
+                              ArgumentsAreASCII, reportp, ap);
+  va_end(ap);
+  return ok;
+}
+/************************************************************************/
+
+JS_PUBLIC_API bool JS_SetDefaultLocale(JSRuntime* rt, const char* locale) {
+  AssertHeapIsIdle();
+  return rt->setDefaultLocale(locale);
+}
+
+JS_PUBLIC_API UniqueChars JS_GetDefaultLocale(JSContext* cx) {
+  AssertHeapIsIdle();
+  if (const char* locale = cx->runtime()->getDefaultLocale()) {
+    return DuplicateString(cx, locale);
+  }
+
+  return nullptr;
+}
+
+JS_PUBLIC_API void JS_ResetDefaultLocale(JSRuntime* rt) {
+  AssertHeapIsIdle();
+  rt->resetDefaultLocale();
+}
+
+JS_PUBLIC_API void JS_SetLocaleCallbacks(JSRuntime* rt,
+                                         const JSLocaleCallbacks* callbacks) {
+  AssertHeapIsIdle();
+  rt->localeCallbacks = callbacks;
+}
+
+JS_PUBLIC_API const JSLocaleCallbacks* JS_GetLocaleCallbacks(JSRuntime* rt) {
+  /* This function can be called by a finalizer. */
+  return rt->localeCallbacks;
+}
+
+/************************************************************************/
+
+JS_PUBLIC_API bool JS_IsExceptionPending(JSContext* cx) {
+  /* This function can be called by a finalizer. */
+  return (bool)cx->isExceptionPending();
+}
+
+JS_PUBLIC_API bool JS_IsThrowingOutOfMemory(JSContext* cx) {
+  return cx->isThrowingOutOfMemory();
+}
+
+JS_PUBLIC_API bool JS_GetPendingException(JSContext* cx,
+                                          MutableHandleValue vp) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (!cx->isExceptionPending()) {
+    return false;
+  }
+  return cx->getPendingException(vp);
+}
+
+JS_PUBLIC_API void JS_SetPendingException(JSContext* cx, HandleValue value,
+                                          JS::ExceptionStackBehavior behavior) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  // We don't check the compartment of `value` here, because we're not
+  // doing anything with it other than storing it, and stored
+  // exception values can be in an abitrary compartment.
+
+  if (behavior == JS::ExceptionStackBehavior::Capture) {
+    cx->setPendingException(value, ShouldCaptureStack::Always);
+  } else {
+    cx->setPendingException(value, nullptr);
+  }
+}
+
+JS_PUBLIC_API void JS_ClearPendingException(JSContext* cx) {
+  AssertHeapIsIdle();
+  cx->clearPendingException();
+}
+
+JS::AutoSaveExceptionState::AutoSaveExceptionState(JSContext* cx)
+    : context(cx), status(cx->status), exceptionValue(cx), exceptionStack(cx) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  if (IsCatchableExceptionStatus(status)) {
+    exceptionValue = cx->unwrappedException();
+    exceptionStack = cx->unwrappedExceptionStack();
+  }
+  cx->clearPendingException();
+}
+
+void JS::AutoSaveExceptionState::drop() {
+  status = JS::ExceptionStatus::None;
+  exceptionValue.setUndefined();
+  exceptionStack = nullptr;
+}
+
+void JS::AutoSaveExceptionState::restore() {
+  context->status = status;
+  context->unwrappedException() = exceptionValue;
+  if (exceptionStack) {
+    context->unwrappedExceptionStack() = &exceptionStack->as<SavedFrame>();
+  }
+  drop();
+}
+
+JS::AutoSaveExceptionState::~AutoSaveExceptionState() {
+  // NOTE: An interrupt/uncatchable exception or a debugger-forced-return may be
+  //       clobbered here by the saved exception. If that is not desired, this
+  //       state should be dropped before the destructor fires.
+  if (!context->isExceptionPending()) {
+    if (status != JS::ExceptionStatus::None) {
+      context->status = status;
+    }
+    if (IsCatchableExceptionStatus(status)) {
+      context->unwrappedException() = exceptionValue;
+      if (exceptionStack) {
+        context->unwrappedExceptionStack() = &exceptionStack->as<SavedFrame>();
+      }
+    }
+  }
+}
+
+JS_PUBLIC_API JSErrorReport* JS_ErrorFromException(JSContext* cx,
+                                                   HandleObject obj) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(obj);
+  return ErrorFromException(cx, obj);
+}
+
+void JSErrorReport::initBorrowedLinebuf(const char16_t* linebufArg,
+                                        size_t linebufLengthArg,
+                                        size_t tokenOffsetArg) {
+  MOZ_ASSERT(linebufArg);
+  MOZ_ASSERT(tokenOffsetArg <= linebufLengthArg);
+  MOZ_ASSERT(linebufArg[linebufLengthArg] == '\0');
+
+  linebuf_ = linebufArg;
+  linebufLength_ = linebufLengthArg;
+  tokenOffset_ = tokenOffsetArg;
+}
+
+void JSErrorReport::freeLinebuf() {
+  if (ownsLinebuf_ && linebuf_) {
+    js_free((void*)linebuf_);
+    ownsLinebuf_ = false;
+  }
+  linebuf_ = nullptr;
+}
+
+JSString* JSErrorBase::newMessageString(JSContext* cx) {
+  if (!message_) {
+    return cx->runtime()->emptyString;
+  }
+
+  return JS_NewStringCopyUTF8Z(cx, message_);
+}
+
+void JSErrorBase::freeMessage() {
+  if (ownsMessage_) {
+    js_free((void*)message_.get());
+    ownsMessage_ = false;
+  }
+  message_ = JS::ConstUTF8CharsZ();
+}
+
+JSErrorNotes::JSErrorNotes() : notes_() {}
+
+JSErrorNotes::~JSErrorNotes() = default;
+
+static UniquePtr<JSErrorNotes::Note> CreateErrorNoteVA(
+    FrontendContext* fc, const char* filename, unsigned sourceId,
+    unsigned lineno, unsigned column, JSErrorCallback errorCallback,
+    void* userRef, const unsigned errorNumber, ErrorArgumentsType argumentsType,
+    va_list ap) {
+  auto note = MakeUnique<JSErrorNotes::Note>();
+  if (!note) {
+    ReportOutOfMemory(fc);
+    return nullptr;
+  }
+
+  note->errorNumber = errorNumber;
+  note->filename = filename;
+  note->sourceId = sourceId;
+  note->lineno = lineno;
+  note->column = column;
+
+  if (!ExpandErrorArgumentsVA(fc, errorCallback, userRef, errorNumber, nullptr,
+                              argumentsType, note.get(), ap)) {
+    return nullptr;
+  }
+
+  return note;
+}
+
+bool JSErrorNotes::addNoteVA(FrontendContext* fc, const char* filename,
+                             unsigned sourceId, unsigned lineno,
+                             unsigned column, JSErrorCallback errorCallback,
+                             void* userRef, const unsigned errorNumber,
+                             ErrorArgumentsType argumentsType, va_list ap) {
+  auto note =
+      CreateErrorNoteVA(fc, filename, sourceId, lineno, column, errorCallback,
+                        userRef, errorNumber, argumentsType, ap);
+
+  if (!note) {
+    return false;
+  }
+  if (!notes_.append(std::move(note))) {
+    ReportOutOfMemory(fc);
+    return false;
+  }
+  return true;
+}
+
+bool JSErrorNotes::addNoteASCII(JSContext* cx, const char* filename,
+                                unsigned sourceId, unsigned lineno,
+                                unsigned column, JSErrorCallback errorCallback,
+                                void* userRef, const unsigned errorNumber,
+                                ...) {
+  AutoReportFrontendContext fc(cx);
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(&fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreASCII, ap);
+  va_end(ap);
+  return ok;
+}
+
+bool JSErrorNotes::addNoteASCII(FrontendContext* fc, const char* filename,
+                                unsigned sourceId, unsigned lineno,
+                                unsigned column, JSErrorCallback errorCallback,
+                                void* userRef, const unsigned errorNumber,
+                                ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreASCII, ap);
+  va_end(ap);
+  return ok;
+}
+
+bool JSErrorNotes::addNoteLatin1(JSContext* cx, const char* filename,
+                                 unsigned sourceId, unsigned lineno,
+                                 unsigned column, JSErrorCallback errorCallback,
+                                 void* userRef, const unsigned errorNumber,
+                                 ...) {
+  AutoReportFrontendContext fc(cx);
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(&fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreLatin1, ap);
+  va_end(ap);
+  return ok;
+}
+
+bool JSErrorNotes::addNoteLatin1(FrontendContext* fc, const char* filename,
+                                 unsigned sourceId, unsigned lineno,
+                                 unsigned column, JSErrorCallback errorCallback,
+                                 void* userRef, const unsigned errorNumber,
+                                 ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreLatin1, ap);
+  va_end(ap);
+  return ok;
+}
+
+bool JSErrorNotes::addNoteUTF8(JSContext* cx, const char* filename,
+                               unsigned sourceId, unsigned lineno,
+                               unsigned column, JSErrorCallback errorCallback,
+                               void* userRef, const unsigned errorNumber, ...) {
+  AutoReportFrontendContext fc(cx);
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(&fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreUTF8, ap);
+  va_end(ap);
+  return ok;
+}
+
+bool JSErrorNotes::addNoteUTF8(FrontendContext* fc, const char* filename,
+                               unsigned sourceId, unsigned lineno,
+                               unsigned column, JSErrorCallback errorCallback,
+                               void* userRef, const unsigned errorNumber, ...) {
+  va_list ap;
+  va_start(ap, errorNumber);
+  bool ok = addNoteVA(fc, filename, sourceId, lineno, column, errorCallback,
+                      userRef, errorNumber, ArgumentsAreUTF8, ap);
+  va_end(ap);
+  return ok;
+}
+
+JS_PUBLIC_API size_t JSErrorNotes::length() { return notes_.length(); }
+
+UniquePtr<JSErrorNotes> JSErrorNotes::copy(JSContext* cx) {
+  auto copiedNotes = MakeUnique<JSErrorNotes>();
+  if (!copiedNotes) {
+    ReportOutOfMemory(cx);
+    return nullptr;
+  }
+
+  for (auto&& note : *this) {
+    UniquePtr<JSErrorNotes::Note> copied = CopyErrorNote(cx, note.get());
+    if (!copied) {
+      return nullptr;
+    }
+
+    if (!copiedNotes->notes_.append(std::move(copied))) {
+      return nullptr;
+    }
+  }
+
+  return copiedNotes;
+}
+
+JS_PUBLIC_API JSErrorNotes::iterator JSErrorNotes::begin() {
+  return iterator(notes_.begin());
+}
+
+JS_PUBLIC_API JSErrorNotes::iterator JSErrorNotes::end() {
+  return iterator(notes_.end());
+}
+
+extern MOZ_NEVER_INLINE JS_PUBLIC_API void JS_AbortIfWrongThread(
+    JSContext* cx) {
+  if (!CurrentThreadCanAccessRuntime(cx->runtime())) {
+    MOZ_CRASH();
+  }
+  if (TlsContext.get() != cx) {
+    MOZ_CRASH();
+  }
+}
+
+#ifdef JS_GC_ZEAL
+JS_PUBLIC_API void JS_GetGCZealBits(JSContext* cx, uint32_t* zealBits,
+                                    uint32_t* frequency,
+                                    uint32_t* nextScheduled) {
+  cx->runtime()->gc.getZealBits(zealBits, frequency, nextScheduled);
+}
+
+JS_PUBLIC_API void JS_SetGCZeal(JSContext* cx, uint8_t zeal,
+                                uint32_t frequency) {
+  cx->runtime()->gc.setZeal(zeal, frequency);
+}
+
+JS_PUBLIC_API void JS_UnsetGCZeal(JSContext* cx, uint8_t zeal) {
+  cx->runtime()->gc.unsetZeal(zeal);
+}
+
+JS_PUBLIC_API void JS_ScheduleGC(JSContext* cx, uint32_t count) {
+  cx->runtime()->gc.setNextScheduled(count);
+}
+#endif
+
+JS_PUBLIC_API void JS_SetParallelParsingEnabled(JSContext* cx, bool enabled) {
+  cx->runtime()->setParallelParsingEnabled(enabled);
+}
+
+JS_PUBLIC_API void JS_SetOffthreadIonCompilationEnabled(JSContext* cx,
+                                                        bool enabled) {
+  cx->runtime()->setOffthreadIonCompilationEnabled(enabled);
+}
+
+JS_PUBLIC_API void JS_SetGlobalJitCompilerOption(JSContext* cx,
+                                                 JSJitCompilerOption opt,
+                                                 uint32_t value) {
+  JSRuntime* rt = cx->runtime();
+  switch (opt) {
+    case JSJITCOMPILER_BASELINE_INTERPRETER_WARMUP_TRIGGER:
+      if (value == uint32_t(-1)) {
+        jit::DefaultJitOptions defaultValues;
+        value = defaultValues.baselineInterpreterWarmUpThreshold;
+      }
+      jit::JitOptions.baselineInterpreterWarmUpThreshold = value;
+      break;
+    case JSJITCOMPILER_BASELINE_WARMUP_TRIGGER:
+      if (value == uint32_t(-1)) {
+        jit::DefaultJitOptions defaultValues;
+        value = defaultValues.baselineJitWarmUpThreshold;
+      }
+      jit::JitOptions.baselineJitWarmUpThreshold = value;
+      break;
+    case JSJITCOMPILER_IC_FORCE_MEGAMORPHIC:
+      jit::JitOptions.forceMegamorphicICs = !!value;
+      break;
+    case JSJITCOMPILER_ION_NORMAL_WARMUP_TRIGGER:
+      if (value == uint32_t(-1)) {
+        jit::JitOptions.resetNormalIonWarmUpThreshold();
+        break;
+      }
+      jit::JitOptions.setNormalIonWarmUpThreshold(value);
+      break;
+    case JSJITCOMPILER_ION_GVN_ENABLE:
+      if (value == 0) {
+        jit::JitOptions.enableGvn(false);
+        JitSpew(js::jit::JitSpew_IonScripts, "Disable ion's GVN");
+      } else {
+        jit::JitOptions.enableGvn(true);
+        JitSpew(js::jit::JitSpew_IonScripts, "Enable ion's GVN");
+      }
+      break;
+    case JSJITCOMPILER_ION_FORCE_IC:
+      if (value == 0) {
+        jit::JitOptions.forceInlineCaches = false;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Ion: Enable non-IC optimizations.");
+      } else {
+        jit::JitOptions.forceInlineCaches = true;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Ion: Disable non-IC optimizations.");
+      }
+      break;
+    case JSJITCOMPILER_ION_CHECK_RANGE_ANALYSIS:
+      if (value == 0) {
+        jit::JitOptions.checkRangeAnalysis = false;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Ion: Enable range analysis checks.");
+      } else {
+        jit::JitOptions.checkRangeAnalysis = true;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Ion: Disable range analysis checks.");
+      }
+      break;
+    case JSJITCOMPILER_ION_ENABLE:
+      if (value == 1) {
+        jit::JitOptions.ion = true;
+        JitSpew(js::jit::JitSpew_IonScripts, "Enable ion");
+      } else if (value == 0) {
+        jit::JitOptions.ion = false;
+        JitSpew(js::jit::JitSpew_IonScripts, "Disable ion");
+      }
+      break;
+    case JSJITCOMPILER_JIT_TRUSTEDPRINCIPALS_ENABLE:
+      if (value == 1) {
+        jit::JitOptions.jitForTrustedPrincipals = true;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Enable ion and baselinejit for trusted principals");
+      } else if (value == 0) {
+        jit::JitOptions.jitForTrustedPrincipals = false;
+        JitSpew(js::jit::JitSpew_IonScripts,
+                "Disable ion and baselinejit for trusted principals");
+      }
+      break;
+    case JSJITCOMPILER_ION_FREQUENT_BAILOUT_THRESHOLD:
+      if (value == uint32_t(-1)) {
+        jit::DefaultJitOptions defaultValues;
+        value = defaultValues.frequentBailoutThreshold;
+      }
+      jit::JitOptions.frequentBailoutThreshold = value;
+      break;
+    case JSJITCOMPILER_BASE_REG_FOR_LOCALS:
+      if (value == 0) {
+        jit::JitOptions.baseRegForLocals = jit::BaseRegForAddress::SP;
+      } else if (value == 1) {
+        jit::JitOptions.baseRegForLocals = jit::BaseRegForAddress::FP;
+      } else {
+        jit::DefaultJitOptions defaultValues;
+        jit::JitOptions.baseRegForLocals = defaultValues.baseRegForLocals;
+      }
+      break;
+    case JSJITCOMPILER_BASELINE_INTERPRETER_ENABLE:
+      if (value == 1) {
+        jit::JitOptions.baselineInterpreter = true;
+      } else if (value == 0) {
+        ReleaseAllJITCode(rt->gcContext());
+        jit::JitOptions.baselineInterpreter = false;
+      }
+      break;
+    case JSJITCOMPILER_BASELINE_ENABLE:
+      if (value == 1) {
+        jit::JitOptions.baselineJit = true;
+        ReleaseAllJITCode(rt->gcContext());
+        JitSpew(js::jit::JitSpew_BaselineScripts, "Enable baseline");
+      } else if (value == 0) {
+        jit::JitOptions.baselineJit = false;
+        ReleaseAllJITCode(rt->gcContext());
+        JitSpew(js::jit::JitSpew_BaselineScripts, "Disable baseline");
+      }
+      break;
+    case JSJITCOMPILER_NATIVE_REGEXP_ENABLE:
+      jit::JitOptions.nativeRegExp = !!value;
+      break;
+    case JSJITCOMPILER_JIT_HINTS_ENABLE:
+      jit::JitOptions.disableJitHints = !value;
+      break;
+    case JSJITCOMPILER_OFFTHREAD_COMPILATION_ENABLE:
+      if (value == 1) {
+        rt->setOffthreadIonCompilationEnabled(true);
+        JitSpew(js::jit::JitSpew_IonScripts, "Enable offthread compilation");
+      } else if (value == 0) {
+        rt->setOffthreadIonCompilationEnabled(false);
+        JitSpew(js::jit::JitSpew_IonScripts, "Disable offthread compilation");
+      }
+      break;
+    case JSJITCOMPILER_INLINING_BYTECODE_MAX_LENGTH:
+      if (value == uint32_t(-1)) {
+        jit::DefaultJitOptions defaultValues;
+        value = defaultValues.smallFunctionMaxBytecodeLength;
+      }
+      jit::JitOptions.smallFunctionMaxBytecodeLength = value;
+      break;
+    case JSJITCOMPILER_JUMP_THRESHOLD:
+      if (value == uint32_t(-1)) {
+        jit::DefaultJitOptions defaultValues;
+        value = defaultValues.jumpThreshold;
+      }
+      jit::JitOptions.jumpThreshold = value;
+      break;
+    case JSJITCOMPILER_SPECTRE_INDEX_MASKING:
+      jit::JitOptions.spectreIndexMasking = !!value;
+      break;
+    case JSJITCOMPILER_SPECTRE_OBJECT_MITIGATIONS:
+      jit::JitOptions.spectreObjectMitigations = !!value;
+      break;
+    case JSJITCOMPILER_SPECTRE_STRING_MITIGATIONS:
+      jit::JitOptions.spectreStringMitigations = !!value;
+      break;
+    case JSJITCOMPILER_SPECTRE_VALUE_MASKING:
+      jit::JitOptions.spectreValueMasking = !!value;
+      break;
+    case JSJITCOMPILER_SPECTRE_JIT_TO_CXX_CALLS:
+      jit::JitOptions.spectreJitToCxxCalls = !!value;
+      break;
+    case JSJITCOMPILER_WATCHTOWER_MEGAMORPHIC:
+      jit::JitOptions.enableWatchtowerMegamorphic = !!value;
+      break;
+    case JSJITCOMPILER_WASM_FOLD_OFFSETS:
+      jit::JitOptions.wasmFoldOffsets = !!value;
+      break;
+    case JSJITCOMPILER_WASM_DELAY_TIER2:
+      jit::JitOptions.wasmDelayTier2 = !!value;
+      break;
+    case JSJITCOMPILER_WASM_JIT_BASELINE:
+      JS::ContextOptionsRef(cx).setWasmBaseline(!!value);
+      break;
+    case JSJITCOMPILER_WASM_JIT_OPTIMIZING:
+      JS::ContextOptionsRef(cx).setWasmIon(!!value);
+      break;
+#ifdef DEBUG
+    case JSJITCOMPILER_FULL_DEBUG_CHECKS:
+      jit::JitOptions.fullDebugChecks = !!value;
+      break;
+#endif
+    default:
+      break;
+  }
+}
+
+JS_PUBLIC_API bool JS_GetGlobalJitCompilerOption(JSContext* cx,
+                                                 JSJitCompilerOption opt,
+                                                 uint32_t* valueOut) {
+  MOZ_ASSERT(valueOut);
+#ifndef JS_CODEGEN_NONE
+  JSRuntime* rt = cx->runtime();
+  switch (opt) {
+    case JSJITCOMPILER_BASELINE_INTERPRETER_WARMUP_TRIGGER:
+      *valueOut = jit::JitOptions.baselineInterpreterWarmUpThreshold;
+      break;
+    case JSJITCOMPILER_BASELINE_WARMUP_TRIGGER:
+      *valueOut = jit::JitOptions.baselineJitWarmUpThreshold;
+      break;
+    case JSJITCOMPILER_IC_FORCE_MEGAMORPHIC:
+      *valueOut = jit::JitOptions.forceMegamorphicICs;
+      break;
+    case JSJITCOMPILER_ION_NORMAL_WARMUP_TRIGGER:
+      *valueOut = jit::JitOptions.normalIonWarmUpThreshold;
+      break;
+    case JSJITCOMPILER_ION_FORCE_IC:
+      *valueOut = jit::JitOptions.forceInlineCaches;
+      break;
+    case JSJITCOMPILER_ION_CHECK_RANGE_ANALYSIS:
+      *valueOut = jit::JitOptions.checkRangeAnalysis;
+      break;
+    case JSJITCOMPILER_ION_ENABLE:
+      *valueOut = jit::JitOptions.ion;
+      break;
+    case JSJITCOMPILER_ION_FREQUENT_BAILOUT_THRESHOLD:
+      *valueOut = jit::JitOptions.frequentBailoutThreshold;
+      break;
+    case JSJITCOMPILER_BASE_REG_FOR_LOCALS:
+      *valueOut = uint32_t(jit::JitOptions.baseRegForLocals);
+      break;
+    case JSJITCOMPILER_INLINING_BYTECODE_MAX_LENGTH:
+      *valueOut = jit::JitOptions.smallFunctionMaxBytecodeLength;
+      break;
+    case JSJITCOMPILER_BASELINE_INTERPRETER_ENABLE:
+      *valueOut = jit::JitOptions.baselineInterpreter;
+      break;
+    case JSJITCOMPILER_BASELINE_ENABLE:
+      *valueOut = jit::JitOptions.baselineJit;
+      break;
+    case JSJITCOMPILER_NATIVE_REGEXP_ENABLE:
+      *valueOut = jit::JitOptions.nativeRegExp;
+      break;
+    case JSJITCOMPILER_OFFTHREAD_COMPILATION_ENABLE:
+      *valueOut = rt->canUseOffthreadIonCompilation();
+      break;
+    case JSJITCOMPILER_SPECTRE_INDEX_MASKING:
+      *valueOut = jit::JitOptions.spectreIndexMasking ? 1 : 0;
+      break;
+    case JSJITCOMPILER_SPECTRE_OBJECT_MITIGATIONS:
+      *valueOut = jit::JitOptions.spectreObjectMitigations ? 1 : 0;
+      break;
+    case JSJITCOMPILER_SPECTRE_STRING_MITIGATIONS:
+      *valueOut = jit::JitOptions.spectreStringMitigations ? 1 : 0;
+      break;
+    case JSJITCOMPILER_SPECTRE_VALUE_MASKING:
+      *valueOut = jit::JitOptions.spectreValueMasking ? 1 : 0;
+      break;
+    case JSJITCOMPILER_SPECTRE_JIT_TO_CXX_CALLS:
+      *valueOut = jit::JitOptions.spectreJitToCxxCalls ? 1 : 0;
+      break;
+    case JSJITCOMPILER_WATCHTOWER_MEGAMORPHIC:
+      *valueOut = jit::JitOptions.enableWatchtowerMegamorphic ? 1 : 0;
+      break;
+    case JSJITCOMPILER_WASM_FOLD_OFFSETS:
+      *valueOut = jit::JitOptions.wasmFoldOffsets ? 1 : 0;
+      break;
+    case JSJITCOMPILER_WASM_JIT_BASELINE:
+      *valueOut = JS::ContextOptionsRef(cx).wasmBaseline() ? 1 : 0;
+      break;
+    case JSJITCOMPILER_WASM_JIT_OPTIMIZING:
+      *valueOut = JS::ContextOptionsRef(cx).wasmIon() ? 1 : 0;
+      break;
+#  ifdef DEBUG
+    case JSJITCOMPILER_FULL_DEBUG_CHECKS:
+      *valueOut = jit::JitOptions.fullDebugChecks ? 1 : 0;
+      break;
+#  endif
+    default:
+      return false;
+  }
+#else
+  *valueOut = 0;
+#endif
+  return true;
+}
+
+JS_PUBLIC_API void JS::DisableSpectreMitigationsAfterInit() {
+  // This is used to turn off Spectre mitigations in pre-allocated child
+  // processes used for isolated web content. Assert there's a single runtime
+  // and cancel off-thread compilations, to ensure we're not racing with any
+  // compilations.
+  JSContext* cx = TlsContext.get();
+  MOZ_RELEASE_ASSERT(cx);
+  MOZ_RELEASE_ASSERT(JSRuntime::hasSingleLiveRuntime());
+  MOZ_RELEASE_ASSERT(cx->runtime()->wasmInstances.lock()->empty());
+
+  CancelOffThreadIonCompile(cx->runtime());
+
+  jit::JitOptions.spectreIndexMasking = false;
+  jit::JitOptions.spectreObjectMitigations = false;
+  jit::JitOptions.spectreStringMitigations = false;
+  jit::JitOptions.spectreValueMasking = false;
+  jit::JitOptions.spectreJitToCxxCalls = false;
+}
+
+/************************************************************************/
+
+#if !defined(STATIC_EXPORTABLE_JS_API) && !defined(STATIC_JS_API) && \
+    defined(XP_WIN) && (defined(MOZ_MEMORY) || !defined(JS_STANDALONE))
+
+#  include "util/WindowsWrapper.h"
+
+/*
+ * Initialization routine for the JS DLL.
+ */
+BOOL WINAPI DllMain(HINSTANCE hDLL, DWORD dwReason, LPVOID lpReserved) {
+  return TRUE;
+}
+
+#endif
+
+JS_PUBLIC_API bool JS_IndexToId(JSContext* cx, uint32_t index,
+                                MutableHandleId id) {
+  return IndexToId(cx, index, id);
+}
+
+JS_PUBLIC_API bool JS_CharsToId(JSContext* cx, JS::TwoByteChars chars,
+                                MutableHandleId idp) {
+  Rooted<JSAtom*> atom(cx,
+                       AtomizeChars(cx, chars.begin().get(), chars.length()));
+  if (!atom) {
+    return false;
+  }
+#ifdef DEBUG
+  MOZ_ASSERT(!atom->isIndex(), "API misuse: |chars| must not encode an index");
+#endif
+  idp.set(AtomToId(atom));
+  return true;
+}
+
+JS_PUBLIC_API bool JS_IsIdentifier(JSContext* cx, HandleString str,
+                                   bool* isIdentifier) {
+  cx->check(str);
+
+  JSLinearString* linearStr = str->ensureLinear(cx);
+  if (!linearStr) {
+    return false;
+  }
+
+  *isIdentifier = js::frontend::IsIdentifier(linearStr);
+  return true;
+}
+
+JS_PUBLIC_API bool JS_IsIdentifier(const char16_t* chars, size_t length) {
+  return js::frontend::IsIdentifier(chars, length);
+}
+
+namespace JS {
+
+void AutoFilename::reset() {
+  if (ss_) {
+    ss_->Release();
+    ss_ = nullptr;
+  }
+  if (filename_.is<const char*>()) {
+    filename_.as<const char*>() = nullptr;
+  } else {
+    filename_.as<UniqueChars>().reset();
+  }
+}
+
+void AutoFilename::setScriptSource(js::ScriptSource* p) {
+  MOZ_ASSERT(!ss_);
+  MOZ_ASSERT(!get());
+  ss_ = p;
+  if (p) {
+    p->AddRef();
+    setUnowned(p->filename());
+  }
+}
+
+void AutoFilename::setUnowned(const char* filename) {
+  MOZ_ASSERT(!get());
+  filename_.as<const char*>() = filename ? filename : "";
+}
+
+void AutoFilename::setOwned(UniqueChars&& filename) {
+  MOZ_ASSERT(!get());
+  filename_ = AsVariant(std::move(filename));
+}
+
+const char* AutoFilename::get() const {
+  if (filename_.is<const char*>()) {
+    return filename_.as<const char*>();
+  }
+  return filename_.as<UniqueChars>().get();
+}
+
+JS_PUBLIC_API bool DescribeScriptedCaller(JSContext* cx, AutoFilename* filename,
+                                          unsigned* lineno, unsigned* column) {
+  if (filename) {
+    filename->reset();
+  }
+  if (lineno) {
+    *lineno = 0;
+  }
+  if (column) {
+    *column = 0;
+  }
+
+  if (!cx->compartment()) {
+    return false;
+  }
+
+  NonBuiltinFrameIter i(cx, cx->realm()->principals());
+  if (i.done()) {
+    return false;
+  }
+
+  // If the caller is hidden, the embedding wants us to return false here so
+  // that it can check its own stack (see HideScriptedCaller).
+  if (i.activation()->scriptedCallerIsHidden()) {
+    return false;
+  }
+
+  if (filename) {
+    if (i.isWasm()) {
+      // For Wasm, copy out the filename, there is no script source.
+      UniqueChars copy = DuplicateString(i.filename() ? i.filename() : "");
+      if (!copy) {
+        filename->setUnowned("out of memory");
+      } else {
+        filename->setOwned(std::move(copy));
+      }
+    } else {
+      // All other frames have a script source to read the filename from.
+      filename->setScriptSource(i.scriptSource());
+    }
+  }
+
+  if (lineno) {
+    *lineno = i.computeLine(column);
+  } else if (column) {
+    i.computeLine(column);
+  }
+
+  return true;
+}
+
+// Fast path to get the activation and realm to use for GetScriptedCallerGlobal.
+// If this returns false, the fast path didn't work out and the caller has to
+// use the (much slower) NonBuiltinFrameIter path.
+//
+// The optimization here is that we skip Ion-inlined frames and only look at
+// 'outer' frames. That's fine because Ion doesn't inline cross-realm calls.
+// However, GetScriptedCallerGlobal has to skip self-hosted frames and Ion
+// can inline self-hosted scripts, so we have to be careful:
+//
+// * When we see a non-self-hosted outer script, it's possible we inlined
+//   self-hosted scripts into it but that doesn't matter because these scripts
+//   all have the same realm/global anyway.
+//
+// * When we see a self-hosted outer script, it's possible we inlined
+//   non-self-hosted scripts into it, so we have to give up because in this
+//   case, whether or not to skip the self-hosted frame (to the possibly
+//   different-realm caller) requires the slow path to handle inlining. Baseline
+//   and the interpreter don't inline so this only affects Ion.
+static bool GetScriptedCallerActivationRealmFast(JSContext* cx,
+                                                 Activation** activation,
+                                                 Realm** realm) {
+  ActivationIterator activationIter(cx);
+
+  if (activationIter.done()) {
+    *activation = nullptr;
+    *realm = nullptr;
+    return true;
+  }
+
+  if (activationIter->isJit()) {
+    jit::JitActivation* act = activationIter->asJit();
+    JitFrameIter iter(act);
+    while (true) {
+      iter.skipNonScriptedJSFrames();
+      if (iter.done()) {
+        break;
+      }
+
+      if (!iter.isSelfHostedIgnoringInlining()) {
+        *activation = act;
+        *realm = iter.realm();
+        return true;
+      }
+
+      if (iter.isJSJit() && iter.asJSJit().isIonScripted()) {
+        // Ion might have inlined non-self-hosted scripts in this
+        // self-hosted script.
+        return false;
+      }
+
+      ++iter;
+    }
+  } else if (activationIter->isInterpreter()) {
+    InterpreterActivation* act = activationIter->asInterpreter();
+    for (InterpreterFrameIterator iter(act); !iter.done(); ++iter) {
+      if (!iter.frame()->script()->selfHosted()) {
+        *activation = act;
+        *realm = iter.frame()->script()->realm();
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+JS_PUBLIC_API JSObject* GetScriptedCallerGlobal(JSContext* cx) {
+  Activation* activation;
+  Realm* realm;
+  if (GetScriptedCallerActivationRealmFast(cx, &activation, &realm)) {
+    if (!activation) {
+      return nullptr;
+    }
+  } else {
+    NonBuiltinFrameIter i(cx);
+    if (i.done()) {
+      return nullptr;
+    }
+    activation = i.activation();
+    realm = i.realm();
+  }
+
+  MOZ_ASSERT(realm->compartment() == activation->compartment());
+
+  // If the caller is hidden, the embedding wants us to return null here so
+  // that it can check its own stack (see HideScriptedCaller).
+  if (activation->scriptedCallerIsHidden()) {
+    return nullptr;
+  }
+
+  GlobalObject* global = realm->maybeGlobal();
+
+  // No one should be running code in a realm without any live objects, so
+  // there should definitely be a live global.
+  MOZ_ASSERT(global);
+
+  return global;
+}
+
+JS_PUBLIC_API void HideScriptedCaller(JSContext* cx) {
+  MOZ_ASSERT(cx);
+
+  // If there's no accessible activation on the stack, we'll return null from
+  // DescribeScriptedCaller anyway, so there's no need to annotate anything.
+  Activation* act = cx->activation();
+  if (!act) {
+    return;
+  }
+  act->hideScriptedCaller();
+}
+
+JS_PUBLIC_API void UnhideScriptedCaller(JSContext* cx) {
+  Activation* act = cx->activation();
+  if (!act) {
+    return;
+  }
+  act->unhideScriptedCaller();
+}
+
+} /* namespace JS */
+
+#ifdef JS_DEBUG
+JS_PUBLIC_API void JS::detail::AssertArgumentsAreSane(JSContext* cx,
+                                                      HandleValue value) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  cx->check(value);
+}
+#endif /* JS_DEBUG */
+
+JS_PUBLIC_API bool JS::FinishIncrementalEncoding(JSContext* cx,
+                                                 JS::HandleScript script,
+                                                 TranscodeBuffer& buffer) {
+  if (!script) {
+    return false;
+  }
+  if (!script->scriptSource()->xdrFinalizeEncoder(cx, buffer)) {
+    return false;
+  }
+  return true;
+}
+
+JS_PUBLIC_API bool JS::FinishIncrementalEncoding(JSContext* cx,
+                                                 JS::Handle<JSObject*> module,
+                                                 TranscodeBuffer& buffer) {
+  if (!module->as<ModuleObject>()
+           .scriptSourceObject()
+           ->source()
+           ->xdrFinalizeEncoder(cx, buffer)) {
+    return false;
+  }
+  return true;
+}
+
+JS_PUBLIC_API void JS::AbortIncrementalEncoding(JS::HandleScript script) {
+  if (!script) {
+    return;
+  }
+  script->scriptSource()->xdrAbortEncoder();
+}
+
+JS_PUBLIC_API void JS::AbortIncrementalEncoding(JS::Handle<JSObject*> module) {
+  module->as<ModuleObject>().scriptSourceObject()->source()->xdrAbortEncoder();
+}
+
+bool JS::IsWasmModuleObject(HandleObject obj) {
+  return obj->canUnwrapAs<WasmModuleObject>();
+}
+
+JS_PUBLIC_API RefPtr<JS::WasmModule> JS::GetWasmModule(HandleObject obj) {
+  MOZ_ASSERT(JS::IsWasmModuleObject(obj));
+  WasmModuleObject& mobj = obj->unwrapAs<WasmModuleObject>();
+  return const_cast<wasm::Module*>(&mobj.module());
+}
+
+bool JS::DisableWasmHugeMemory() { return wasm::DisableHugeMemory(); }
+
+JS_PUBLIC_API void JS::SetProcessLargeAllocationFailureCallback(
+    JS::LargeAllocationFailureCallback lafc) {
+  MOZ_ASSERT(!OnLargeAllocationFailure);
+  OnLargeAllocationFailure = lafc;
+}
+
+JS_PUBLIC_API void JS::SetOutOfMemoryCallback(JSContext* cx,
+                                              OutOfMemoryCallback cb,
+                                              void* data) {
+  cx->runtime()->oomCallback = cb;
+  cx->runtime()->oomCallbackData = data;
+}
+
+JS_PUBLIC_API void JS::SetShadowRealmInitializeGlobalCallback(
+    JSContext* cx, JS::GlobalInitializeCallback callback) {
+  cx->runtime()->shadowRealmInitializeGlobalCallback = callback;
+}
+
+JS_PUBLIC_API void JS::SetShadowRealmGlobalCreationCallback(
+    JSContext* cx, JS::GlobalCreationCallback callback) {
+  cx->runtime()->shadowRealmGlobalCreationCallback = callback;
+}
+
+JS::FirstSubsumedFrame::FirstSubsumedFrame(
+    JSContext* cx, bool ignoreSelfHostedFrames /* = true */)
+    : JS::FirstSubsumedFrame(cx, cx->realm()->principals(),
+                             ignoreSelfHostedFrames) {}
+
+JS_PUBLIC_API bool JS::CaptureCurrentStack(
+    JSContext* cx, JS::MutableHandleObject stackp,
+    JS::StackCapture&& capture /* = JS::StackCapture(JS::AllFrames()) */) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  MOZ_RELEASE_ASSERT(cx->realm());
+
+  Realm* realm = cx->realm();
+  Rooted<SavedFrame*> frame(cx);
+  if (!realm->savedStacks().saveCurrentStack(cx, &frame, std::move(capture))) {
+    return false;
+  }
+  stackp.set(frame.get());
+  return true;
+}
+
+JS_PUBLIC_API bool JS::IsAsyncStackCaptureEnabledForRealm(JSContext* cx) {
+  if (!cx->options().asyncStack()) {
+    return false;
+  }
+
+  if (!cx->options().asyncStackCaptureDebuggeeOnly() ||
+      cx->realm()->isDebuggee()) {
+    return true;
+  }
+
+  return cx->realm()->isAsyncStackCapturingEnabled;
+}
+
+JS_PUBLIC_API bool JS::CopyAsyncStack(JSContext* cx,
+                                      JS::HandleObject asyncStack,
+                                      JS::HandleString asyncCause,
+                                      JS::MutableHandleObject stackp,
+                                      const Maybe<size_t>& maxFrameCount) {
+  AssertHeapIsIdle();
+  CHECK_THREAD(cx);
+  MOZ_RELEASE_ASSERT(cx->realm());
+
+  js::AssertObjectIsSavedFrameOrWrapper(cx, asyncStack);
+  Realm* realm = cx->realm();
+  Rooted<SavedFrame*> frame(cx);
+  if (!realm->savedStacks().copyAsyncStack(cx, asyncStack, asyncCause, &frame,
+                                           maxFrameCount)) {
+    return false;
+  }
+  stackp.set(frame.get());
+  return true;
+}
+
+JS_PUBLIC_API Zone* JS::GetObjectZone(JSObject* obj) { return obj->zone(); }
+
+JS_PUBLIC_API Zone* JS::GetNurseryCellZone(gc::Cell* cell) {
+  return cell->nurseryZone();
+}
+
+JS_PUBLIC_API JS::TraceKind JS::GCThingTraceKind(void* thing) {
+  MOZ_ASSERT(thing);
+  return static_cast<js::gc::Cell*>(thing)->getTraceKind();
+}
+
+JS_PUBLIC_API void js::SetStackFormat(JSContext* cx, js::StackFormat format) {
+  cx->runtime()->setStackFormat(format);
+}
+
+JS_PUBLIC_API js::StackFormat js::GetStackFormat(JSContext* cx) {
+  return cx->runtime()->stackFormat();
+}
+
+JS_PUBLIC_API JS::JSTimers JS::GetJSTimers(JSContext* cx) {
+  return cx->realm()->timers;
+}
+
+namespace js {
+
+JS_PUBLIC_API void NoteIntentionalCrash() {
+#ifdef __linux__
+  static bool* addr =
+      reinterpret_cast<bool*>(dlsym(RTLD_DEFAULT, "gBreakpadInjectorEnabled"));
+  if (addr) {
+    *addr = false;
+  }
+#endif
+}
+
+#ifdef DEBUG
+bool gSupportDifferentialTesting = false;
+#endif  // DEBUG
+
+}  // namespace js
+
+#ifdef DEBUG
+
+JS_PUBLIC_API void JS::SetSupportDifferentialTesting(bool value) {
+  js::gSupportDifferentialTesting = value;
+}
+
+#endif  // DEBUG