Adding upstream version 124.0.1.upstream/124.0.1

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

1 files changed, 1107 insertions, 0 deletions

diff --git a/js/src/vm/GlobalObject.cpp b/js/src/vm/GlobalObject.cpp
new file mode 100644
index 0000000000..9c9003a2ba
--- /dev/null
+++ b/js/src/vm/GlobalObject.cpp
@@ -0,0 +1,1107 @@
+/* -*- 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/. */
+
+#include "vm/GlobalObject.h"
+
+#include "jsapi.h"
+#include "jsfriendapi.h"
+
+#include "builtin/AtomicsObject.h"
+#include "builtin/BigInt.h"
+#include "builtin/DataViewObject.h"
+#ifdef JS_HAS_INTL_API
+#  include "builtin/intl/Collator.h"
+#  include "builtin/intl/DateTimeFormat.h"
+#  include "builtin/intl/DisplayNames.h"
+#  include "builtin/intl/ListFormat.h"
+#  include "builtin/intl/Locale.h"
+#  include "builtin/intl/NumberFormat.h"
+#  include "builtin/intl/PluralRules.h"
+#  include "builtin/intl/RelativeTimeFormat.h"
+#  include "builtin/intl/Segmenter.h"
+#endif
+#include "builtin/FinalizationRegistryObject.h"
+#include "builtin/MapObject.h"
+#include "builtin/ShadowRealm.h"
+#include "builtin/Symbol.h"
+#ifdef JS_HAS_TEMPORAL_API
+#  include "builtin/temporal/Calendar.h"
+#  include "builtin/temporal/Duration.h"
+#  include "builtin/temporal/Instant.h"
+#  include "builtin/temporal/PlainDate.h"
+#  include "builtin/temporal/PlainDateTime.h"
+#  include "builtin/temporal/PlainMonthDay.h"
+#  include "builtin/temporal/PlainTime.h"
+#  include "builtin/temporal/PlainYearMonth.h"
+#  include "builtin/temporal/Temporal.h"
+#  include "builtin/temporal/TemporalNow.h"
+#  include "builtin/temporal/TimeZone.h"
+#  include "builtin/temporal/ZonedDateTime.h"
+#endif
+#include "builtin/WeakMapObject.h"
+#include "builtin/WeakRefObject.h"
+#include "builtin/WeakSetObject.h"
+#include "debugger/DebugAPI.h"
+#include "frontend/CompilationStencil.h"
+#include "gc/FinalizationObservers.h"
+#include "gc/GC.h"
+#include "gc/GCContext.h"
+#include "js/friend/ErrorMessages.h"  // js::GetErrorMessage, JSMSG_*
+#include "js/friend/WindowProxy.h"    // js::ToWindowProxyIfWindow
+#include "js/Prefs.h"                 // JS::Prefs
+#include "js/PropertyAndElement.h"    // JS_DefineFunctions, JS_DefineProperties
+#include "js/ProtoKey.h"
+#include "vm/AsyncFunction.h"
+#include "vm/AsyncIteration.h"
+#include "vm/BooleanObject.h"
+#include "vm/Compartment.h"
+#include "vm/DateObject.h"
+#include "vm/EnvironmentObject.h"
+#include "vm/ErrorObject.h"
+#include "vm/GeneratorObject.h"
+#include "vm/JSContext.h"
+#include "vm/NumberObject.h"
+#include "vm/PIC.h"
+#include "vm/PlainObject.h"
+#include "vm/RegExpObject.h"
+#include "vm/RegExpStatics.h"
+#include "vm/SelfHosting.h"
+#include "vm/StringObject.h"
+#include "wasm/WasmFeatures.h"
+#include "wasm/WasmJS.h"
+#ifdef ENABLE_RECORD_TUPLE
+#  include "vm/RecordType.h"
+#  include "vm/TupleType.h"
+#endif
+
+#include "gc/GCContext-inl.h"
+#include "vm/JSObject-inl.h"
+#include "vm/Realm-inl.h"
+
+using namespace js;
+
+namespace js {
+
+extern const JSClass IntlClass;
+extern const JSClass JSONClass;
+extern const JSClass MathClass;
+extern const JSClass ReflectClass;
+
+}  // namespace js
+
+static const JSClass* const protoTable[JSProto_LIMIT] = {
+#define INIT_FUNC(name, clasp) clasp,
+#define INIT_FUNC_DUMMY(name, clasp) nullptr,
+    JS_FOR_PROTOTYPES(INIT_FUNC, INIT_FUNC_DUMMY)
+#undef INIT_FUNC_DUMMY
+#undef INIT_FUNC
+};
+
+JS_PUBLIC_API const JSClass* js::ProtoKeyToClass(JSProtoKey key) {
+  MOZ_ASSERT(key < JSProto_LIMIT);
+  return protoTable[key];
+}
+
+static bool IsIteratorHelpersEnabled() {
+#ifdef NIGHTLY_BUILD
+  return JS::Prefs::experimental_iterator_helpers();
+#else
+  return false;
+#endif
+}
+
+/* static */
+bool GlobalObject::skipDeselectedConstructor(JSContext* cx, JSProtoKey key) {
+  switch (key) {
+    case JSProto_Null:
+    case JSProto_Object:
+    case JSProto_Function:
+    case JSProto_BoundFunction:
+    case JSProto_Array:
+    case JSProto_Boolean:
+    case JSProto_JSON:
+    case JSProto_Date:
+    case JSProto_Math:
+    case JSProto_Number:
+    case JSProto_String:
+    case JSProto_RegExp:
+    case JSProto_Error:
+    case JSProto_InternalError:
+    case JSProto_AggregateError:
+    case JSProto_EvalError:
+    case JSProto_RangeError:
+    case JSProto_ReferenceError:
+    case JSProto_SyntaxError:
+    case JSProto_TypeError:
+    case JSProto_URIError:
+    case JSProto_DebuggeeWouldRun:
+    case JSProto_CompileError:
+    case JSProto_LinkError:
+    case JSProto_RuntimeError:
+    case JSProto_ArrayBuffer:
+    case JSProto_Int8Array:
+    case JSProto_Uint8Array:
+    case JSProto_Int16Array:
+    case JSProto_Uint16Array:
+    case JSProto_Int32Array:
+    case JSProto_Uint32Array:
+    case JSProto_Float32Array:
+    case JSProto_Float64Array:
+    case JSProto_Uint8ClampedArray:
+    case JSProto_BigInt64Array:
+    case JSProto_BigUint64Array:
+    case JSProto_BigInt:
+    case JSProto_Proxy:
+    case JSProto_WeakMap:
+    case JSProto_Map:
+    case JSProto_Set:
+    case JSProto_DataView:
+    case JSProto_Symbol:
+    case JSProto_Reflect:
+    case JSProto_WeakSet:
+    case JSProto_TypedArray:
+    case JSProto_SavedFrame:
+    case JSProto_Promise:
+    case JSProto_AsyncFunction:
+    case JSProto_GeneratorFunction:
+    case JSProto_AsyncGeneratorFunction:
+#ifdef ENABLE_RECORD_TUPLE
+    case JSProto_Record:
+    case JSProto_Tuple:
+#endif
+      return false;
+
+    case JSProto_WebAssembly:
+      return !wasm::HasSupport(cx);
+
+    case JSProto_WasmModule:
+    case JSProto_WasmInstance:
+    case JSProto_WasmMemory:
+    case JSProto_WasmTable:
+    case JSProto_WasmGlobal:
+    case JSProto_WasmTag:
+#ifdef ENABLE_WASM_TYPE_REFLECTIONS
+    case JSProto_WasmFunction:
+#endif
+    case JSProto_WasmException:
+      return false;
+
+#ifdef JS_HAS_INTL_API
+    case JSProto_Intl:
+    case JSProto_Collator:
+    case JSProto_DateTimeFormat:
+    case JSProto_DisplayNames:
+    case JSProto_Locale:
+    case JSProto_ListFormat:
+    case JSProto_NumberFormat:
+    case JSProto_PluralRules:
+    case JSProto_RelativeTimeFormat:
+      return false;
+
+    case JSProto_Segmenter:
+#  if defined(MOZ_ICU4X) && defined(NIGHTLY_BUILD)
+      return false;
+#  else
+      return true;
+#  endif
+#endif
+
+#ifdef JS_HAS_TEMPORAL_API
+    case JSProto_Temporal:
+    case JSProto_Calendar:
+    case JSProto_Duration:
+    case JSProto_Instant:
+    case JSProto_PlainDate:
+    case JSProto_PlainDateTime:
+    case JSProto_PlainMonthDay:
+    case JSProto_PlainTime:
+    case JSProto_PlainYearMonth:
+    case JSProto_TemporalNow:
+    case JSProto_TimeZone:
+    case JSProto_ZonedDateTime:
+      return false;
+#endif
+
+    // Return true if the given constructor has been disabled at run-time.
+    case JSProto_Atomics:
+    case JSProto_SharedArrayBuffer:
+      return !cx->realm()->creationOptions().getSharedMemoryAndAtomicsEnabled();
+
+    case JSProto_WeakRef:
+    case JSProto_FinalizationRegistry:
+      return JS::GetWeakRefsEnabled() == JS::WeakRefSpecifier::Disabled;
+
+    case JSProto_Iterator:
+    case JSProto_AsyncIterator:
+      return !IsIteratorHelpersEnabled();
+
+    case JSProto_ShadowRealm:
+      return !JS::Prefs::experimental_shadow_realms();
+
+    default:
+      MOZ_CRASH("unexpected JSProtoKey");
+  }
+}
+
+static bool ShouldFreezeBuiltin(JSProtoKey key) {
+  // We can't freeze Reflect because JS_InitReflectParse defines Reflect.parse.
+  if (key == JSProto_Reflect) {
+    return false;
+  }
+  // We can't freeze Date because some browser tests use the Sinon library which
+  // redefines Date.now.
+  if (key == JSProto_Date) {
+    return false;
+  }
+  return true;
+}
+
+static unsigned GetAttrsForResolvedGlobal(GlobalObject* global,
+                                          JSProtoKey key) {
+  unsigned attrs = JSPROP_RESOLVING;
+  if (global->realm()->creationOptions().freezeBuiltins() &&
+      ShouldFreezeBuiltin(key)) {
+    attrs |= JSPROP_PERMANENT | JSPROP_READONLY;
+  }
+  return attrs;
+}
+
+/* static*/
+bool GlobalObject::resolveConstructor(JSContext* cx,
+                                      Handle<GlobalObject*> global,
+                                      JSProtoKey key, IfClassIsDisabled mode) {
+  MOZ_ASSERT(key != JSProto_Null);
+  MOZ_ASSERT(key != JSProto_BoundFunction,
+             "bound functions don't have their own proto object");
+  MOZ_ASSERT(!global->isStandardClassResolved(key));
+  MOZ_ASSERT(cx->compartment() == global->compartment());
+
+  // |global| must be same-compartment but make sure we're in its realm: the
+  // code below relies on this.
+  AutoRealm ar(cx, global);
+
+  // Prohibit collection of allocation metadata. Metadata builders shouldn't
+  // need to observe lazily-constructed prototype objects coming into
+  // existence. And assertions start to fail when the builder itself attempts
+  // an allocation that re-entrantly tries to create the same prototype.
+  AutoSuppressAllocationMetadataBuilder suppressMetadata(cx);
+
+  // Constructor resolution may execute self-hosted scripts. These
+  // self-hosted scripts do not call out to user code by construction. Allow
+  // all scripts to execute, even in debuggee compartments that are paused.
+  AutoSuppressDebuggeeNoExecuteChecks suppressNX(cx);
+
+  // Some classes can be disabled at compile time, others at run time;
+  // if a feature is compile-time disabled, clasp is null.
+  const JSClass* clasp = ProtoKeyToClass(key);
+  if (!clasp || skipDeselectedConstructor(cx, key)) {
+    if (mode == IfClassIsDisabled::Throw) {
+      JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
+                                JSMSG_CONSTRUCTOR_DISABLED,
+                                clasp ? clasp->name : "constructor");
+      return false;
+    }
+    return true;
+  }
+
+  // Class spec must have a constructor defined.
+  if (!clasp->specDefined()) {
+    return true;
+  }
+
+  bool isObjectOrFunction = key == JSProto_Function || key == JSProto_Object;
+
+  // We need to create the prototype first, and immediately stash it in the
+  // slot. This is so the following bootstrap ordering is possible:
+  // * Object.prototype
+  // * Function.prototype
+  // * Function
+  // * Object
+  //
+  // We get the above when Object is resolved before Function. If Function
+  // is resolved before Object, we'll end up re-entering resolveConstructor
+  // for Function, which is a problem. So if Function is being resolved
+  // before Object.prototype exists, we just resolve Object instead, since we
+  // know that Function will also be resolved before we return.
+  if (key == JSProto_Function && !global->hasPrototype(JSProto_Object)) {
+    return resolveConstructor(cx, global, JSProto_Object,
+                              IfClassIsDisabled::DoNothing);
+  }
+
+  // %IteratorPrototype%.map.[[Prototype]] is %Generator% and
+  // %Generator%.prototype.[[Prototype]] is %IteratorPrototype%.
+  // A workaround in initIteratorProto prevents runaway mutual recursion while
+  // setting these up. Ensure the workaround is triggered already:
+  if (key == JSProto_GeneratorFunction &&
+      !global->hasBuiltinProto(ProtoKind::IteratorProto)) {
+    if (!getOrCreateIteratorPrototype(cx, global)) {
+      return false;
+    }
+
+    // If iterator helpers are enabled, populating %IteratorPrototype% will
+    // have recursively gone through here.
+    if (global->isStandardClassResolved(key)) {
+      return true;
+    }
+  }
+
+  // We don't always have a prototype (i.e. Math and JSON). If we don't,
+  // |createPrototype|, |prototypeFunctions|, and |prototypeProperties|
+  // should all be null.
+  RootedObject proto(cx);
+  if (ClassObjectCreationOp createPrototype =
+          clasp->specCreatePrototypeHook()) {
+    proto = createPrototype(cx, key);
+    if (!proto) {
+      return false;
+    }
+
+    if (isObjectOrFunction) {
+      // Make sure that creating the prototype didn't recursively resolve
+      // our own constructor. We can't just assert that there's no
+      // prototype; OOMs can result in incomplete resolutions in which
+      // the prototype is saved but not the constructor. So use the same
+      // criteria that protects entry into this function.
+      MOZ_ASSERT(!global->isStandardClassResolved(key));
+
+      global->setPrototype(key, proto);
+    }
+  }
+
+  // Create the constructor.
+  RootedObject ctor(cx, clasp->specCreateConstructorHook()(cx, key));
+  if (!ctor) {
+    return false;
+  }
+
+  RootedId id(cx, NameToId(ClassName(key, cx)));
+  if (isObjectOrFunction) {
+    if (clasp->specShouldDefineConstructor()) {
+      RootedValue ctorValue(cx, ObjectValue(*ctor));
+      unsigned attrs = GetAttrsForResolvedGlobal(global, key);
+      if (!DefineDataProperty(cx, global, id, ctorValue, attrs)) {
+        return false;
+      }
+    }
+
+    global->setConstructor(key, ctor);
+  }
+
+  if (const JSFunctionSpec* funs = clasp->specPrototypeFunctions()) {
+    if (!JS_DefineFunctions(cx, proto, funs)) {
+      return false;
+    }
+  }
+  if (const JSPropertySpec* props = clasp->specPrototypeProperties()) {
+    if (!JS_DefineProperties(cx, proto, props)) {
+      return false;
+    }
+  }
+  if (const JSFunctionSpec* funs = clasp->specConstructorFunctions()) {
+    if (!JS_DefineFunctions(cx, ctor, funs)) {
+      return false;
+    }
+  }
+  if (const JSPropertySpec* props = clasp->specConstructorProperties()) {
+    if (!JS_DefineProperties(cx, ctor, props)) {
+      return false;
+    }
+  }
+
+  // If the prototype exists, link it with the constructor.
+  if (proto && !LinkConstructorAndPrototype(cx, ctor, proto)) {
+    return false;
+  }
+
+  // Call the post-initialization hook, if provided.
+  if (FinishClassInitOp finishInit = clasp->specFinishInitHook()) {
+    if (!finishInit(cx, ctor, proto)) {
+      return false;
+    }
+  }
+
+  if (ShouldFreezeBuiltin(key)) {
+    if (!JS::MaybeFreezeCtorAndPrototype(cx, ctor, proto)) {
+      return false;
+    }
+  }
+
+  if (!isObjectOrFunction) {
+    // Any operations that modifies the global object should be placed
+    // after any other fallible operations.
+
+    // Fallible operation that modifies the global object.
+    if (clasp->specShouldDefineConstructor()) {
+      bool shouldReallyDefine = true;
+
+      // 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.
+      if (key == JSProto_SharedArrayBuffer) {
+        const JS::RealmCreationOptions& options =
+            global->realm()->creationOptions();
+
+        MOZ_ASSERT(options.getSharedMemoryAndAtomicsEnabled(),
+                   "shouldn't be defining SharedArrayBuffer if shared memory "
+                   "is disabled");
+
+        shouldReallyDefine = options.defineSharedArrayBufferConstructor();
+      }
+
+      if (shouldReallyDefine) {
+        RootedValue ctorValue(cx, ObjectValue(*ctor));
+        unsigned attrs = GetAttrsForResolvedGlobal(global, key);
+        if (!DefineDataProperty(cx, global, id, ctorValue, attrs)) {
+          return false;
+        }
+      }
+    }
+
+    // Infallible operations that modify the global object.
+    global->setConstructor(key, ctor);
+    if (proto) {
+      global->setPrototype(key, proto);
+    }
+  }
+
+  return true;
+}
+
+// Resolve a "globalThis" self-referential property if necessary,
+// per a stage-3 proposal. https://github.com/tc39/ecma262/pull/702
+//
+// We could also do this in |FinishObjectClassInit| to trim the global
+// resolve hook.  Unfortunately, |ToWindowProxyIfWindow| doesn't work then:
+// the browser's |nsGlobalWindow::SetNewDocument| invokes Object init
+// *before* it sets the global's WindowProxy using |js::SetWindowProxy|.
+//
+// Refactoring global object creation code to support this approach is a
+// challenge for another day.
+/* static */
+bool GlobalObject::maybeResolveGlobalThis(JSContext* cx,
+                                          Handle<GlobalObject*> global,
+                                          bool* resolved) {
+  if (!global->data().globalThisResolved) {
+    RootedValue v(cx, ObjectValue(*ToWindowProxyIfWindow(global)));
+    if (!DefineDataProperty(cx, global, cx->names().globalThis, v,
+                            JSPROP_RESOLVING)) {
+      return false;
+    }
+
+    *resolved = true;
+    global->data().globalThisResolved = true;
+  }
+
+  return true;
+}
+
+/* static */
+JSObject* GlobalObject::createBuiltinProto(JSContext* cx,
+                                           Handle<GlobalObject*> global,
+                                           ProtoKind kind, ObjectInitOp init) {
+  if (!init(cx, global)) {
+    return nullptr;
+  }
+
+  return &global->getBuiltinProto(kind);
+}
+
+JSObject* GlobalObject::createBuiltinProto(JSContext* cx,
+                                           Handle<GlobalObject*> global,
+                                           ProtoKind kind, Handle<JSAtom*> tag,
+                                           ObjectInitWithTagOp init) {
+  if (!init(cx, global, tag)) {
+    return nullptr;
+  }
+
+  return &global->getBuiltinProto(kind);
+}
+
+static bool ThrowTypeError(JSContext* cx, unsigned argc, Value* vp) {
+  ThrowTypeErrorBehavior(cx);
+  return false;
+}
+
+/* static */
+JSObject* GlobalObject::getOrCreateThrowTypeError(
+    JSContext* cx, Handle<GlobalObject*> global) {
+  if (JSFunction* fun = global->data().throwTypeError) {
+    return fun;
+  }
+
+  // Construct the unique [[%ThrowTypeError%]] function object, used only for
+  // "callee" and "caller" accessors on strict mode arguments objects.  (The
+  // spec also uses this for "arguments" and "caller" on various functions,
+  // but we're experimenting with implementing them using accessors on
+  // |Function.prototype| right now.)
+
+  RootedFunction throwTypeError(
+      cx, NewNativeFunction(cx, ThrowTypeError, 0, nullptr));
+  if (!throwTypeError || !PreventExtensions(cx, throwTypeError)) {
+    return nullptr;
+  }
+
+  // The "length" property of %ThrowTypeError% is non-configurable.
+  Rooted<PropertyDescriptor> nonConfigurableDesc(cx,
+                                                 PropertyDescriptor::Empty());
+  nonConfigurableDesc.setConfigurable(false);
+
+  RootedId lengthId(cx, NameToId(cx->names().length));
+  ObjectOpResult lengthResult;
+  if (!NativeDefineProperty(cx, throwTypeError, lengthId, nonConfigurableDesc,
+                            lengthResult)) {
+    return nullptr;
+  }
+  MOZ_ASSERT(lengthResult);
+
+  // The "name" property of %ThrowTypeError% is non-configurable, adjust
+  // the default property attributes accordingly.
+  RootedId nameId(cx, NameToId(cx->names().name));
+  ObjectOpResult nameResult;
+  if (!NativeDefineProperty(cx, throwTypeError, nameId, nonConfigurableDesc,
+                            nameResult)) {
+    return nullptr;
+  }
+  MOZ_ASSERT(nameResult);
+
+  global->data().throwTypeError.init(throwTypeError);
+  return throwTypeError;
+}
+
+GlobalObject* GlobalObject::createInternal(JSContext* cx,
+                                           const JSClass* clasp) {
+  MOZ_ASSERT(clasp->flags & JSCLASS_IS_GLOBAL);
+  MOZ_ASSERT(clasp->isTrace(JS_GlobalObjectTraceHook));
+
+  JSObject* obj = NewTenuredObjectWithGivenProto(cx, clasp, nullptr);
+  if (!obj) {
+    return nullptr;
+  }
+
+  Rooted<GlobalObject*> global(cx, &obj->as<GlobalObject>());
+  MOZ_ASSERT(global->isUnqualifiedVarObj());
+
+  {
+    auto data = cx->make_unique<GlobalObjectData>(cx->zone());
+    if (!data) {
+      return nullptr;
+    }
+    // Note: it's important for the realm's global to be initialized at the
+    // same time as the global's GlobalObjectData, because we free the global's
+    // data when Realm::global_ is cleared.
+    cx->realm()->initGlobal(*global);
+    InitReservedSlot(global, GLOBAL_DATA_SLOT, data.release(),
+                     MemoryUse::GlobalObjectData);
+  }
+
+  Rooted<GlobalLexicalEnvironmentObject*> lexical(
+      cx, GlobalLexicalEnvironmentObject::create(cx, global));
+  if (!lexical) {
+    return nullptr;
+  }
+  global->data().lexicalEnvironment.init(lexical);
+
+  Rooted<GlobalScope*> emptyGlobalScope(
+      cx, GlobalScope::createEmpty(cx, ScopeKind::Global));
+  if (!emptyGlobalScope) {
+    return nullptr;
+  }
+  global->data().emptyGlobalScope.init(emptyGlobalScope);
+
+  if (!GlobalObject::createIntrinsicsHolder(cx, global)) {
+    return nullptr;
+  }
+
+  if (!JSObject::setQualifiedVarObj(cx, global)) {
+    return nullptr;
+  }
+  if (!JSObject::setGenerationCountedGlobal(cx, global)) {
+    return nullptr;
+  }
+
+  return global;
+}
+
+/* static */
+GlobalObject* GlobalObject::new_(JSContext* cx, const JSClass* clasp,
+                                 JSPrincipals* principals,
+                                 JS::OnNewGlobalHookOption hookOption,
+                                 const JS::RealmOptions& options) {
+  MOZ_ASSERT(!cx->isExceptionPending());
+  MOZ_ASSERT_IF(cx->zone(), !cx->zone()->isAtomsZone());
+
+  // If we are creating a new global in an existing compartment, make sure the
+  // compartment has a live global at all times (by rooting it here).
+  // See bug 1530364.
+  Rooted<GlobalObject*> existingGlobal(cx);
+  const JS::RealmCreationOptions& creationOptions = options.creationOptions();
+  if (creationOptions.compartmentSpecifier() ==
+      JS::CompartmentSpecifier::ExistingCompartment) {
+    Compartment* comp = creationOptions.compartment();
+    existingGlobal = &comp->firstGlobal();
+  }
+
+  Realm* realm = NewRealm(cx, principals, options);
+  if (!realm) {
+    return nullptr;
+  }
+
+  Rooted<GlobalObject*> global(cx);
+  {
+    AutoRealmUnchecked ar(cx, realm);
+    global = GlobalObject::createInternal(cx, clasp);
+    if (!global) {
+      return nullptr;
+    }
+
+    // Make transactional initialization of these constructors by discarding the
+    // incompletely initialized global if an error occur. This also ensures the
+    // global's prototype chain is initialized (in FinishObjectClassInit).
+    if (!ensureConstructor(cx, global, JSProto_Object) ||
+        !ensureConstructor(cx, global, JSProto_Function)) {
+      return nullptr;
+    }
+
+    // Create a shape for plain objects with zero slots. This is required to be
+    // present in case allocating dynamic slots for objects fails, so we can
+    // leave a valid object in the heap.
+    if (!createPlainObjectShapeWithDefaultProto(cx, gc::AllocKind::OBJECT0)) {
+      return nullptr;
+    }
+
+    realm->clearInitializingGlobal();
+    if (hookOption == JS::FireOnNewGlobalHook) {
+      JS_FireOnNewGlobalObject(cx, global);
+    }
+  }
+
+  return global;
+}
+
+GlobalScope& GlobalObject::emptyGlobalScope() const {
+  return *data().emptyGlobalScope;
+}
+
+bool GlobalObject::valueIsEval(const Value& val) {
+  return val.isObject() && data().eval == &val.toObject();
+}
+
+/* static */
+bool GlobalObject::initStandardClasses(JSContext* cx,
+                                       Handle<GlobalObject*> global) {
+  /* Define a top-level property 'undefined' with the undefined value. */
+  if (!DefineDataProperty(
+          cx, global, cx->names().undefined, UndefinedHandleValue,
+          JSPROP_PERMANENT | JSPROP_READONLY | JSPROP_RESOLVING)) {
+    return false;
+  }
+
+  // Resolve a "globalThis" self-referential property if necessary.
+  bool resolved;
+  if (!GlobalObject::maybeResolveGlobalThis(cx, global, &resolved)) {
+    return false;
+  }
+
+  for (size_t k = 0; k < JSProto_LIMIT; ++k) {
+    JSProtoKey key = static_cast<JSProtoKey>(k);
+    if (key != JSProto_Null && key != JSProto_BoundFunction &&
+        !global->isStandardClassResolved(key)) {
+      if (!resolveConstructor(cx, global, static_cast<JSProtoKey>(k),
+                              IfClassIsDisabled::DoNothing)) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+/* static */
+JSFunction* GlobalObject::createConstructor(JSContext* cx, Native ctor,
+                                            JSAtom* nameArg, unsigned length,
+                                            gc::AllocKind kind,
+                                            const JSJitInfo* jitInfo) {
+  Rooted<JSAtom*> name(cx, nameArg);
+  JSFunction* fun = NewNativeConstructor(cx, ctor, length, name, kind);
+  if (!fun) {
+    return nullptr;
+  }
+
+  if (jitInfo) {
+    fun->setJitInfo(jitInfo);
+  }
+
+  return fun;
+}
+
+static NativeObject* CreateBlankProto(JSContext* cx, const JSClass* clasp,
+                                      HandleObject proto,
+                                      ObjectFlags objFlags) {
+  MOZ_ASSERT(!clasp->isJSFunction());
+
+  if (clasp == &PlainObject::class_) {
+    // NOTE: There should be no reason currently to support this. It could
+    // however be added later if needed.
+    MOZ_ASSERT(objFlags.isEmpty());
+    return NewPlainObjectWithProto(cx, proto, TenuredObject);
+  }
+
+  return NewTenuredObjectWithGivenProto(cx, clasp, proto, objFlags);
+}
+
+/* static */
+NativeObject* GlobalObject::createBlankPrototype(JSContext* cx,
+                                                 Handle<GlobalObject*> global,
+                                                 const JSClass* clasp,
+                                                 ObjectFlags objFlags) {
+  RootedObject objectProto(cx, &global->getObjectPrototype());
+  return CreateBlankProto(cx, clasp, objectProto, objFlags);
+}
+
+/* static */
+NativeObject* GlobalObject::createBlankPrototypeInheriting(JSContext* cx,
+                                                           const JSClass* clasp,
+                                                           HandleObject proto) {
+  return CreateBlankProto(cx, clasp, proto, ObjectFlags());
+}
+
+bool js::LinkConstructorAndPrototype(JSContext* cx, JSObject* ctor_,
+                                     JSObject* proto_, unsigned prototypeAttrs,
+                                     unsigned constructorAttrs) {
+  RootedObject ctor(cx, ctor_), proto(cx, proto_);
+
+  RootedValue protoVal(cx, ObjectValue(*proto));
+  RootedValue ctorVal(cx, ObjectValue(*ctor));
+
+  return DefineDataProperty(cx, ctor, cx->names().prototype, protoVal,
+                            prototypeAttrs) &&
+         DefineDataProperty(cx, proto, cx->names().constructor, ctorVal,
+                            constructorAttrs);
+}
+
+bool js::DefinePropertiesAndFunctions(JSContext* cx, HandleObject obj,
+                                      const JSPropertySpec* ps,
+                                      const JSFunctionSpec* fs) {
+  if (ps && !JS_DefineProperties(cx, obj, ps)) {
+    return false;
+  }
+  if (fs && !JS_DefineFunctions(cx, obj, fs)) {
+    return false;
+  }
+  return true;
+}
+
+bool js::DefineToStringTag(JSContext* cx, HandleObject obj, JSAtom* tag) {
+  RootedId toStringTagId(
+      cx, PropertyKey::Symbol(cx->wellKnownSymbols().toStringTag));
+  RootedValue tagString(cx, StringValue(tag));
+  return DefineDataProperty(cx, obj, toStringTagId, tagString, JSPROP_READONLY);
+}
+
+/* static */
+NativeObject* GlobalObject::getOrCreateForOfPICObject(
+    JSContext* cx, Handle<GlobalObject*> global) {
+  cx->check(global);
+  NativeObject* forOfPIC = global->getForOfPICObject();
+  if (forOfPIC) {
+    return forOfPIC;
+  }
+
+  forOfPIC = ForOfPIC::createForOfPICObject(cx, global);
+  if (!forOfPIC) {
+    return nullptr;
+  }
+  global->data().forOfPICChain.init(forOfPIC);
+  return forOfPIC;
+}
+
+/* static */
+JSObject* GlobalObject::getOrCreateRealmKeyObject(
+    JSContext* cx, Handle<GlobalObject*> global) {
+  cx->check(global);
+  if (PlainObject* key = global->data().realmKeyObject) {
+    return key;
+  }
+
+  PlainObject* key = NewPlainObject(cx);
+  if (!key) {
+    return nullptr;
+  }
+
+  global->data().realmKeyObject.init(key);
+  return key;
+}
+
+/* static */
+RegExpStatics* GlobalObject::getRegExpStatics(JSContext* cx,
+                                              Handle<GlobalObject*> global) {
+  MOZ_ASSERT(cx);
+
+  if (!global->regExpRealm().regExpStatics) {
+    auto statics = RegExpStatics::create(cx);
+    if (!statics) {
+      return nullptr;
+    }
+    global->regExpRealm().regExpStatics = std::move(statics);
+  }
+
+  return global->regExpRealm().regExpStatics.get();
+}
+
+gc::FinalizationRegistryGlobalData*
+GlobalObject::getOrCreateFinalizationRegistryData() {
+  if (!data().finalizationRegistryData) {
+    data().finalizationRegistryData =
+        MakeUnique<gc::FinalizationRegistryGlobalData>(zone());
+  }
+
+  return maybeFinalizationRegistryData();
+}
+
+bool GlobalObject::addToVarNames(JSContext* cx, JS::Handle<JSAtom*> name) {
+  MOZ_ASSERT(name);
+
+  if (!data().varNames.put(name)) {
+    ReportOutOfMemory(cx);
+    return false;
+  }
+
+  return true;
+}
+
+/* static */
+bool GlobalObject::createIntrinsicsHolder(JSContext* cx,
+                                          Handle<GlobalObject*> global) {
+  Rooted<NativeObject*> intrinsicsHolder(
+      cx, NewPlainObjectWithProto(cx, nullptr, TenuredObject));
+  if (!intrinsicsHolder) {
+    return false;
+  }
+
+  // Install the intrinsics holder on the global.
+  global->data().intrinsicsHolder.init(intrinsicsHolder);
+  return true;
+}
+
+/* static */
+bool GlobalObject::getSelfHostedFunction(JSContext* cx,
+                                         Handle<GlobalObject*> global,
+                                         Handle<PropertyName*> selfHostedName,
+                                         Handle<JSAtom*> name, unsigned nargs,
+                                         MutableHandleValue funVal) {
+  if (global->maybeGetIntrinsicValue(selfHostedName, funVal.address(), cx)) {
+    RootedFunction fun(cx, &funVal.toObject().as<JSFunction>());
+    if (fun->fullExplicitName() == name) {
+      return true;
+    }
+
+    if (fun->fullExplicitName() == selfHostedName) {
+      // This function was initially cloned because it was called by
+      // other self-hosted code, so the clone kept its self-hosted name,
+      // instead of getting the name it's intended to have in content
+      // compartments. This can happen when a lazy builtin is initialized
+      // after self-hosted code for another builtin used the same
+      // function. In that case, we need to change the function's name,
+      // which is ok because it can't have been exposed to content
+      // before.
+      fun->setAtom(name);
+      return true;
+    }
+
+    // The function might be installed multiple times on the same or
+    // different builtins, under different property names, so its name
+    // might be neither "selfHostedName" nor "name". In that case, its
+    // canonical name must've been set using the `_SetCanonicalName`
+    // intrinsic.
+    cx->runtime()->assertSelfHostedFunctionHasCanonicalName(selfHostedName);
+    return true;
+  }
+
+  JSRuntime* runtime = cx->runtime();
+  frontend::ScriptIndex index =
+      runtime->getSelfHostedScriptIndexRange(selfHostedName)->start;
+  JSFunction* fun =
+      runtime->selfHostStencil().instantiateSelfHostedLazyFunction(
+          cx, runtime->selfHostStencilInput().atomCache, index, name);
+  if (!fun) {
+    return false;
+  }
+  MOZ_ASSERT(fun->nargs() == nargs);
+  funVal.setObject(*fun);
+
+  return GlobalObject::addIntrinsicValue(cx, global, selfHostedName, funVal);
+}
+
+/* static */
+bool GlobalObject::getIntrinsicValueSlow(JSContext* cx,
+                                         Handle<GlobalObject*> global,
+                                         Handle<PropertyName*> name,
+                                         MutableHandleValue value) {
+  // If this is a C++ intrinsic, simply define the function on the intrinsics
+  // holder.
+  if (const JSFunctionSpec* spec = js::FindIntrinsicSpec(name)) {
+    RootedId id(cx, NameToId(name));
+    RootedFunction fun(cx, JS::NewFunctionFromSpec(cx, spec, id));
+    if (!fun) {
+      return false;
+    }
+    fun->setIsIntrinsic();
+
+    value.setObject(*fun);
+    return GlobalObject::addIntrinsicValue(cx, global, name, value);
+  }
+
+  if (!cx->runtime()->getSelfHostedValue(cx, name, value)) {
+    return false;
+  }
+
+  // It's possible in certain edge cases that cloning the value ended up
+  // defining the intrinsic. For instance, cloning can call NewArray, which
+  // resolves Array.prototype, which defines some self-hosted functions. If this
+  // happens we use the value already defined on the intrinsics holder.
+  if (global->maybeGetIntrinsicValue(name, value.address(), cx)) {
+    return true;
+  }
+
+  return GlobalObject::addIntrinsicValue(cx, global, name, value);
+}
+
+/* static */
+bool GlobalObject::addIntrinsicValue(JSContext* cx,
+                                     Handle<GlobalObject*> global,
+                                     Handle<PropertyName*> name,
+                                     HandleValue value) {
+  Rooted<NativeObject*> holder(cx, &global->getIntrinsicsHolder());
+
+  RootedId id(cx, NameToId(name));
+  MOZ_ASSERT(!holder->containsPure(id));
+
+  constexpr PropertyFlags propFlags = {PropertyFlag::Configurable,
+                                       PropertyFlag::Writable};
+  uint32_t slot;
+  if (!NativeObject::addProperty(cx, holder, id, propFlags, &slot)) {
+    return false;
+  }
+  holder->initSlot(slot, value);
+  return true;
+}
+
+/* static */
+JSObject* GlobalObject::createIteratorPrototype(JSContext* cx,
+                                                Handle<GlobalObject*> global) {
+  if (!IsIteratorHelpersEnabled()) {
+    return getOrCreateBuiltinProto(cx, global, ProtoKind::IteratorProto,
+                                   initIteratorProto);
+  }
+
+  if (!ensureConstructor(cx, global, JSProto_Iterator)) {
+    return nullptr;
+  }
+  JSObject* proto = &global->getPrototype(JSProto_Iterator);
+  global->initBuiltinProto(ProtoKind::IteratorProto, proto);
+  return proto;
+}
+
+/* static */
+JSObject* GlobalObject::createAsyncIteratorPrototype(
+    JSContext* cx, Handle<GlobalObject*> global) {
+  if (!IsIteratorHelpersEnabled()) {
+    return getOrCreateBuiltinProto(cx, global, ProtoKind::AsyncIteratorProto,
+                                   initAsyncIteratorProto);
+  }
+
+  if (!ensureConstructor(cx, global, JSProto_AsyncIterator)) {
+    return nullptr;
+  }
+  JSObject* proto = &global->getPrototype(JSProto_AsyncIterator);
+  global->initBuiltinProto(ProtoKind::AsyncIteratorProto, proto);
+  return proto;
+}
+
+void GlobalObject::releaseData(JS::GCContext* gcx) {
+  GlobalObjectData* data = maybeData();
+  setReservedSlot(GLOBAL_DATA_SLOT, PrivateValue(nullptr));
+  gcx->delete_(this, data, MemoryUse::GlobalObjectData);
+}
+
+GlobalObjectData::GlobalObjectData(Zone* zone) : varNames(zone) {}
+
+GlobalObjectData::~GlobalObjectData() = default;
+
+void GlobalObjectData::trace(JSTracer* trc, GlobalObject* global) {
+  // Atoms are always tenured so don't need to be traced during minor GC.
+  if (trc->runtime()->heapState() != JS::HeapState::MinorCollecting) {
+    varNames.trace(trc);
+  }
+
+  for (auto& ctorWithProto : builtinConstructors) {
+    TraceNullableEdge(trc, &ctorWithProto.constructor, "global-builtin-ctor");
+    TraceNullableEdge(trc, &ctorWithProto.prototype,
+                      "global-builtin-ctor-proto");
+  }
+
+  for (auto& proto : builtinProtos) {
+    TraceNullableEdge(trc, &proto, "global-builtin-proto");
+  }
+
+  TraceNullableEdge(trc, &emptyGlobalScope, "global-empty-scope");
+
+  TraceNullableEdge(trc, &lexicalEnvironment, "global-lexical-env");
+  TraceNullableEdge(trc, &windowProxy, "global-window-proxy");
+  TraceNullableEdge(trc, &intrinsicsHolder, "global-intrinsics-holder");
+  TraceNullableEdge(trc, &computedIntrinsicsHolder,
+                    "global-computed-intrinsics-holder");
+  TraceNullableEdge(trc, &forOfPICChain, "global-for-of-pic");
+  TraceNullableEdge(trc, &sourceURLsHolder, "global-source-urls");
+  TraceNullableEdge(trc, &realmKeyObject, "global-realm-key");
+  TraceNullableEdge(trc, &throwTypeError, "global-throw-type-error");
+  TraceNullableEdge(trc, &eval, "global-eval");
+  TraceNullableEdge(trc, &emptyIterator, "global-empty-iterator");
+
+  TraceNullableEdge(trc, &arrayShapeWithDefaultProto, "global-array-shape");
+
+  for (auto& shape : plainObjectShapesWithDefaultProto) {
+    TraceNullableEdge(trc, &shape, "global-plain-shape");
+  }
+
+  TraceNullableEdge(trc, &functionShapeWithDefaultProto,
+                    "global-function-shape");
+  TraceNullableEdge(trc, &extendedFunctionShapeWithDefaultProto,
+                    "global-ext-function-shape");
+
+  TraceNullableEdge(trc, &boundFunctionShapeWithDefaultProto,
+                    "global-bound-function-shape");
+
+  regExpRealm.trace(trc);
+
+  TraceNullableEdge(trc, &mappedArgumentsTemplate, "mapped-arguments-template");
+  TraceNullableEdge(trc, &unmappedArgumentsTemplate,
+                    "unmapped-arguments-template");
+
+  TraceNullableEdge(trc, &iterResultTemplate, "iter-result-template_");
+  TraceNullableEdge(trc, &iterResultWithoutPrototypeTemplate,
+                    "iter-result-without-prototype-template");
+
+  TraceNullableEdge(trc, &selfHostingScriptSource,
+                    "self-hosting-script-source");
+
+  if (finalizationRegistryData) {
+    finalizationRegistryData->trace(trc);
+  }
+}
+
+void GlobalObjectData::addSizeOfIncludingThis(
+    mozilla::MallocSizeOf mallocSizeOf, JS::ClassInfo* info) const {
+  info->objectsMallocHeapGlobalData += mallocSizeOf(this);
+
+  if (regExpRealm.regExpStatics) {
+    info->objectsMallocHeapGlobalData +=
+        regExpRealm.regExpStatics->sizeOfIncludingThis(mallocSizeOf);
+  }
+
+  info->objectsMallocHeapGlobalVarNamesSet +=
+      varNames.shallowSizeOfExcludingThis(mallocSizeOf);
+}