Adding upstream version 86.0.1.upstream/86.0.1upstream

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

1 files changed, 673 insertions, 0 deletions

diff --git a/js/src/vm/JSObject-inl.h b/js/src/vm/JSObject-inl.h
new file mode 100644
index 0000000000..3090bc0be5
--- /dev/null
+++ b/js/src/vm/JSObject-inl.h
@@ -0,0 +1,673 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_JSObject_inl_h
+#define vm_JSObject_inl_h
+
+#include "vm/JSObject.h"
+
+#include "js/Object.h"  // JS::GetBuiltinClass
+#include "vm/ArrayObject.h"
+#include "vm/EnvironmentObject.h"
+#include "vm/JSFunction.h"
+#include "vm/Probes.h"
+#include "vm/TypedArrayObject.h"
+
+#include "gc/FreeOp-inl.h"
+#include "gc/Marking-inl.h"
+#include "gc/ObjectKind-inl.h"
+#include "vm/ObjectOperations-inl.h"  // js::MaybeHasInterestingSymbolProperty
+#include "vm/Realm-inl.h"
+
+namespace js {
+
+/*
+ * Get the GC kind to use for scripted 'new' on the given class.
+ * FIXME bug 547327: estimate the size from the allocation site.
+ */
+static inline gc::AllocKind NewObjectGCKind(const JSClass* clasp) {
+  if (clasp == &ArrayObject::class_) {
+    return gc::AllocKind::OBJECT8;
+  }
+  if (clasp == &JSFunction::class_) {
+    return gc::AllocKind::OBJECT2;
+  }
+  return gc::AllocKind::OBJECT4;
+}
+
+}  // namespace js
+
+MOZ_ALWAYS_INLINE uint32_t js::NativeObject::numDynamicSlots() const {
+  uint32_t slots = getSlotsHeader()->capacity();
+  MOZ_ASSERT(slots == calculateDynamicSlots());
+  MOZ_ASSERT_IF(hasDynamicSlots(), slots != 0);
+
+  return slots;
+}
+
+MOZ_ALWAYS_INLINE uint32_t js::NativeObject::calculateDynamicSlots() const {
+  return calculateDynamicSlots(numFixedSlots(), slotSpan(), getClass());
+}
+
+/* static */ MOZ_ALWAYS_INLINE uint32_t js::NativeObject::calculateDynamicSlots(
+    uint32_t nfixed, uint32_t span, const JSClass* clasp) {
+  if (span <= nfixed) {
+    return 0;
+  }
+
+  uint32_t ndynamic = span - nfixed;
+
+  // Increase the slots to SLOT_CAPACITY_MIN to decrease the likelihood
+  // the dynamic slots need to get increased again. ArrayObjects ignore
+  // this because slots are uncommon in that case.
+  if (clasp != &ArrayObject::class_ && ndynamic <= SLOT_CAPACITY_MIN) {
+    return SLOT_CAPACITY_MIN;
+  }
+
+  uint32_t count =
+      mozilla::RoundUpPow2(ndynamic + ObjectSlots::VALUES_PER_HEADER);
+
+  uint32_t slots = count - ObjectSlots::VALUES_PER_HEADER;
+  MOZ_ASSERT(slots >= ndynamic);
+  return slots;
+}
+
+/* static */ MOZ_ALWAYS_INLINE uint32_t
+js::NativeObject::calculateDynamicSlots(Shape* shape) {
+  return calculateDynamicSlots(shape->numFixedSlots(), shape->slotSpan(),
+                               shape->getObjectClass());
+}
+
+inline void JSObject::finalize(JSFreeOp* fop) {
+  js::probes::FinalizeObject(this);
+
+#ifdef DEBUG
+  MOZ_ASSERT(isTenured());
+  if (!IsBackgroundFinalized(asTenured().getAllocKind())) {
+    /* Assert we're on the main thread. */
+    MOZ_ASSERT(CurrentThreadCanAccessZone(zone()));
+  }
+#endif
+
+  const JSClass* clasp = getClass();
+  js::NativeObject* nobj = nullptr;
+  if (clasp->isNative()) {
+    nobj = &as<js::NativeObject>();
+  }
+  if (clasp->hasFinalize()) {
+    clasp->doFinalize(fop, this);
+  }
+
+  if (!nobj) {
+    return;
+  }
+
+  if (nobj->hasDynamicSlots()) {
+    js::ObjectSlots* slotsHeader = nobj->getSlotsHeader();
+    size_t size = js::ObjectSlots::allocSize(slotsHeader->capacity());
+    fop->free_(this, slotsHeader, size, js::MemoryUse::ObjectSlots);
+  }
+
+  if (nobj->hasDynamicElements()) {
+    js::ObjectElements* elements = nobj->getElementsHeader();
+    size_t size = elements->numAllocatedElements() * sizeof(js::HeapSlot);
+    fop->free_(this, nobj->getUnshiftedElementsHeader(), size,
+               js::MemoryUse::ObjectElements);
+  }
+}
+
+MOZ_ALWAYS_INLINE void js::NativeObject::sweepDictionaryListPointer() {
+  // Dictionary mode shapes can have pointers to nursery-allocated
+  // objects. There's no postbarrier for this pointer so this method is called
+  // to clear it when such an object dies.
+  MOZ_ASSERT(inDictionaryMode());
+  if (shape()->dictNext == DictionaryShapeLink(this)) {
+    shape()->dictNext.setNone();
+  }
+}
+
+MOZ_ALWAYS_INLINE void
+js::NativeObject::updateDictionaryListPointerAfterMinorGC(NativeObject* old) {
+  MOZ_ASSERT(this == Forwarded(old));
+
+  // Dictionary objects can be allocated in the nursery and when they are
+  // tenured the shape's pointer to the object needs to be updated.
+  if (shape()->dictNext == DictionaryShapeLink(old)) {
+    shape()->dictNext = DictionaryShapeLink(this);
+  }
+}
+
+inline void JSObject::setGroup(js::ObjectGroup* group) {
+  MOZ_RELEASE_ASSERT(group);
+  MOZ_ASSERT(maybeCCWRealm() == group->realm());
+  setGroupRaw(group);
+}
+
+/* * */
+
+inline bool JSObject::isQualifiedVarObj() const {
+  if (is<js::DebugEnvironmentProxy>()) {
+    return as<js::DebugEnvironmentProxy>().environment().isQualifiedVarObj();
+  }
+  bool rv = hasAllFlags(js::BaseShape::QUALIFIED_VAROBJ);
+  MOZ_ASSERT_IF(rv, is<js::GlobalObject>() || is<js::CallObject>() ||
+                        is<js::VarEnvironmentObject>() ||
+                        is<js::ModuleEnvironmentObject>() ||
+                        is<js::NonSyntacticVariablesObject>() ||
+                        (is<js::WithEnvironmentObject>() &&
+                         !as<js::WithEnvironmentObject>().isSyntactic()));
+  return rv;
+}
+
+inline bool JSObject::isUnqualifiedVarObj() const {
+  if (is<js::DebugEnvironmentProxy>()) {
+    return as<js::DebugEnvironmentProxy>().environment().isUnqualifiedVarObj();
+  }
+  return is<js::GlobalObject>() || is<js::NonSyntacticVariablesObject>();
+}
+
+namespace js {
+
+inline bool ClassCanHaveFixedData(const JSClass* clasp) {
+  // Normally, the number of fixed slots given an object is the maximum
+  // permitted for its size class. For array buffers and non-shared typed
+  // arrays we only use enough to cover the class reserved slots, so that
+  // the remaining space in the object's allocation is available for the
+  // buffer's data.
+  return !clasp->isNative() || clasp == &js::ArrayBufferObject::class_ ||
+         js::IsTypedArrayClass(clasp);
+}
+
+class MOZ_RAII AutoSuppressAllocationMetadataBuilder {
+  JS::Zone* zone;
+  bool saved;
+
+ public:
+  explicit AutoSuppressAllocationMetadataBuilder(JSContext* cx)
+      : zone(cx->zone()), saved(zone->suppressAllocationMetadataBuilder) {
+    zone->suppressAllocationMetadataBuilder = true;
+  }
+
+  ~AutoSuppressAllocationMetadataBuilder() {
+    zone->suppressAllocationMetadataBuilder = saved;
+  }
+};
+
+// This function is meant to be called from allocation fast paths.
+//
+// If we do have an allocation metadata builder, it can cause a GC, so the
+// object must be rooted. The usual way to do this would be to make our callers
+// pass a HandleObject, but that would require them to pay the cost of rooting
+// the object unconditionally, even though collecting metadata is rare. Instead,
+// SetNewObjectMetadata's contract is that the caller must use the pointer
+// returned in place of the pointer passed. If a GC occurs, the returned pointer
+// may be the passed pointer, relocated by GC. If no GC could occur, it's just
+// passed through. We root nothing unless necessary.
+template <typename T>
+static MOZ_ALWAYS_INLINE MOZ_MUST_USE T* SetNewObjectMetadata(JSContext* cx,
+                                                              T* obj) {
+  MOZ_ASSERT(!cx->realm()->hasObjectPendingMetadata());
+
+  // The metadata builder is invoked for each object created on the active
+  // thread, except when analysis/compilation is active, to avoid recursion.
+  if (!cx->isHelperThreadContext()) {
+    if (MOZ_UNLIKELY(cx->realm()->hasAllocationMetadataBuilder()) &&
+        !cx->zone()->suppressAllocationMetadataBuilder) {
+      // Don't collect metadata on objects that represent metadata.
+      AutoSuppressAllocationMetadataBuilder suppressMetadata(cx);
+
+      Rooted<T*> rooted(cx, obj);
+      cx->realm()->setNewObjectMetadata(cx, rooted);
+      return rooted;
+    }
+  }
+
+  return obj;
+}
+
+}  // namespace js
+
+inline js::GlobalObject& JSObject::nonCCWGlobal() const {
+  /*
+   * The global is read-barriered so that it is kept live by access through
+   * the Realm. When accessed through a JSObject, however, the global will be
+   * already kept live by the black JSObject's group pointer, so does not
+   * need to be read-barriered.
+   */
+  return *nonCCWRealm()->unsafeUnbarrieredMaybeGlobal();
+}
+
+inline bool JSObject::hasAllFlags(js::BaseShape::Flag flags) const {
+  MOZ_ASSERT(flags);
+  return shape()->hasAllObjectFlags(flags);
+}
+
+inline bool JSObject::nonProxyIsExtensible() const {
+  MOZ_ASSERT(!uninlinedIsProxy());
+
+  // [[Extensible]] for ordinary non-proxy objects is an object flag.
+  return !hasAllFlags(js::BaseShape::NOT_EXTENSIBLE);
+}
+
+inline bool JSObject::isBoundFunction() const {
+  return is<JSFunction>() && as<JSFunction>().isBoundFunction();
+}
+
+inline bool JSObject::isDelegate() const {
+  return hasAllFlags(js::BaseShape::DELEGATE);
+}
+
+inline bool JSObject::hasUncacheableProto() const {
+  return hasAllFlags(js::BaseShape::UNCACHEABLE_PROTO);
+}
+
+MOZ_ALWAYS_INLINE bool JSObject::maybeHasInterestingSymbolProperty() const {
+  if (isNative()) {
+    return as<js::NativeObject>().hasInterestingSymbol();
+  }
+  return true;
+}
+
+inline bool JSObject::staticPrototypeIsImmutable() const {
+  MOZ_ASSERT(hasStaticPrototype());
+  return hasAllFlags(js::BaseShape::IMMUTABLE_PROTOTYPE);
+}
+
+namespace js {
+
+static MOZ_ALWAYS_INLINE bool IsFunctionObject(const js::Value& v) {
+  return v.isObject() && v.toObject().is<JSFunction>();
+}
+
+static MOZ_ALWAYS_INLINE bool IsFunctionObject(const js::Value& v,
+                                               JSFunction** fun) {
+  if (v.isObject() && v.toObject().is<JSFunction>()) {
+    *fun = &v.toObject().as<JSFunction>();
+    return true;
+  }
+  return false;
+}
+
+static MOZ_ALWAYS_INLINE bool IsNativeFunction(const js::Value& v) {
+  JSFunction* fun;
+  return IsFunctionObject(v, &fun) && fun->isNative();
+}
+
+static MOZ_ALWAYS_INLINE bool IsNativeFunction(const js::Value& v,
+                                               JSFunction** fun) {
+  return IsFunctionObject(v, fun) && (*fun)->isNative();
+}
+
+static MOZ_ALWAYS_INLINE bool IsNativeFunction(const js::Value& v,
+                                               JSNative native) {
+  JSFunction* fun;
+  return IsFunctionObject(v, &fun) && fun->maybeNative() == native;
+}
+
+static MOZ_ALWAYS_INLINE bool IsNativeFunction(const JSObject* obj,
+                                               JSNative native) {
+  return obj->is<JSFunction>() && obj->as<JSFunction>().maybeNative() == native;
+}
+
+// Return whether looking up a method on 'obj' definitely resolves to the
+// original specified native function. The method may conservatively return
+// 'false' in the case of proxies or other non-native objects.
+static MOZ_ALWAYS_INLINE bool HasNativeMethodPure(JSObject* obj,
+                                                  PropertyName* name,
+                                                  JSNative native,
+                                                  JSContext* cx) {
+  Value v;
+  if (!GetPropertyPure(cx, obj, NameToId(name), &v)) {
+    return false;
+  }
+
+  return IsNativeFunction(v, native);
+}
+
+// Return whether 'obj' definitely has no @@toPrimitive method.
+static MOZ_ALWAYS_INLINE bool HasNoToPrimitiveMethodPure(JSObject* obj,
+                                                         JSContext* cx) {
+  JS::Symbol* toPrimitive = cx->wellKnownSymbols().toPrimitive;
+  JSObject* holder;
+  if (!MaybeHasInterestingSymbolProperty(cx, obj, toPrimitive, &holder)) {
+#ifdef DEBUG
+    JSObject* pobj;
+    PropertyResult prop;
+    MOZ_ASSERT(
+        LookupPropertyPure(cx, obj, SYMBOL_TO_JSID(toPrimitive), &pobj, &prop));
+    MOZ_ASSERT(!prop);
+#endif
+    return true;
+  }
+
+  JSObject* pobj;
+  PropertyResult prop;
+  if (!LookupPropertyPure(cx, holder, SYMBOL_TO_JSID(toPrimitive), &pobj,
+                          &prop)) {
+    return false;
+  }
+
+  return !prop;
+}
+
+extern bool ToPropertyKeySlow(JSContext* cx, HandleValue argument,
+                              MutableHandleId result);
+
+/* ES6 draft rev 28 (2014 Oct 14) 7.1.14 */
+MOZ_ALWAYS_INLINE bool ToPropertyKey(JSContext* cx, HandleValue argument,
+                                     MutableHandleId result) {
+  if (MOZ_LIKELY(argument.isPrimitive())) {
+    return PrimitiveValueToId<CanGC>(cx, argument, result);
+  }
+
+  return ToPropertyKeySlow(cx, argument, result);
+}
+
+/*
+ * Return true if this is a compiler-created internal function accessed by
+ * its own object. Such a function object must not be accessible to script
+ * or embedding code.
+ */
+inline bool IsInternalFunctionObject(JSObject& funobj) {
+  JSFunction& fun = funobj.as<JSFunction>();
+  return fun.isInterpreted() && !fun.environment();
+}
+
+inline gc::InitialHeap GetInitialHeap(NewObjectKind newKind,
+                                      const JSClass* clasp) {
+  if (newKind != GenericObject) {
+    return gc::TenuredHeap;
+  }
+  if (clasp->hasFinalize() && !CanNurseryAllocateFinalizedClass(clasp)) {
+    return gc::TenuredHeap;
+  }
+  return gc::DefaultHeap;
+}
+
+inline gc::InitialHeap GetInitialHeap(NewObjectKind newKind,
+                                      ObjectGroup* group) {
+  return GetInitialHeap(newKind, group->clasp());
+}
+
+/*
+ * Make an object with the specified prototype. If parent is null, it will
+ * default to the prototype's global if the prototype is non-null.
+ */
+JSObject* NewObjectWithGivenTaggedProto(JSContext* cx, const JSClass* clasp,
+                                        Handle<TaggedProto> proto,
+                                        gc::AllocKind allocKind,
+                                        NewObjectKind newKind,
+                                        uint32_t initialShapeFlags = 0);
+
+template <NewObjectKind NewKind>
+inline JSObject* NewObjectWithGivenTaggedProto(JSContext* cx,
+                                               const JSClass* clasp,
+                                               Handle<TaggedProto> proto) {
+  gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
+  return NewObjectWithGivenTaggedProto(cx, clasp, proto, allocKind, NewKind, 0);
+}
+
+namespace detail {
+
+template <typename T, NewObjectKind NewKind>
+inline T* NewObjectWithGivenTaggedProtoForKind(JSContext* cx,
+                                               Handle<TaggedProto> proto) {
+  JSObject* obj = NewObjectWithGivenTaggedProto<NewKind>(cx, &T::class_, proto);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+}  // namespace detail
+
+template <typename T>
+inline T* NewObjectWithGivenTaggedProto(JSContext* cx,
+                                        Handle<TaggedProto> proto) {
+  return detail::NewObjectWithGivenTaggedProtoForKind<T, GenericObject>(cx,
+                                                                        proto);
+}
+
+inline JSObject* NewObjectWithGivenProto(
+    JSContext* cx, const JSClass* clasp, HandleObject proto,
+    gc::AllocKind allocKind, NewObjectKind newKind = GenericObject) {
+  return NewObjectWithGivenTaggedProto(cx, clasp, AsTaggedProto(proto),
+                                       allocKind, newKind);
+}
+
+inline JSObject* NewObjectWithGivenProto(JSContext* cx, const JSClass* clasp,
+                                         HandleObject proto) {
+  return NewObjectWithGivenTaggedProto<GenericObject>(cx, clasp,
+                                                      AsTaggedProto(proto));
+}
+
+inline JSObject* NewTenuredObjectWithGivenProto(JSContext* cx,
+                                                const JSClass* clasp,
+                                                HandleObject proto) {
+  return NewObjectWithGivenTaggedProto<TenuredObject>(cx, clasp,
+                                                      AsTaggedProto(proto));
+}
+
+template <typename T>
+inline T* NewObjectWithGivenProto(JSContext* cx, HandleObject proto) {
+  return detail::NewObjectWithGivenTaggedProtoForKind<T, GenericObject>(
+      cx, AsTaggedProto(proto));
+}
+
+template <typename T>
+inline T* NewTenuredObjectWithGivenProto(JSContext* cx, HandleObject proto) {
+  return detail::NewObjectWithGivenTaggedProtoForKind<T, TenuredObject>(
+      cx, AsTaggedProto(proto));
+}
+
+template <typename T>
+inline T* NewObjectWithGivenProtoAndKinds(JSContext* cx, HandleObject proto,
+                                          gc::AllocKind allocKind,
+                                          NewObjectKind newKind) {
+  JSObject* obj = NewObjectWithGivenTaggedProto(
+      cx, &T::class_, AsTaggedProto(proto), allocKind, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+// Make an object with the prototype set according to the cached prototype or
+// Object.prototype.
+JSObject* NewObjectWithClassProto(JSContext* cx, const JSClass* clasp,
+                                  HandleObject proto, gc::AllocKind allocKind,
+                                  NewObjectKind newKind = GenericObject);
+
+inline JSObject* NewObjectWithClassProto(
+    JSContext* cx, const JSClass* clasp, HandleObject proto,
+    NewObjectKind newKind = GenericObject) {
+  gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
+  return NewObjectWithClassProto(cx, clasp, proto, allocKind, newKind);
+}
+
+template <class T>
+inline T* NewObjectWithClassProto(JSContext* cx, HandleObject proto) {
+  JSObject* obj = NewObjectWithClassProto(cx, &T::class_, proto, GenericObject);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <class T>
+inline T* NewObjectWithClassProtoAndKind(JSContext* cx, HandleObject proto,
+                                         NewObjectKind newKind) {
+  JSObject* obj = NewObjectWithClassProto(cx, &T::class_, proto, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <class T>
+inline T* NewObjectWithClassProto(JSContext* cx, HandleObject proto,
+                                  gc::AllocKind allocKind,
+                                  NewObjectKind newKind = GenericObject) {
+  JSObject* obj =
+      NewObjectWithClassProto(cx, &T::class_, proto, allocKind, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+/*
+ * Create a native instance of the given class with parent and proto set
+ * according to the context's active global.
+ */
+inline JSObject* NewBuiltinClassInstance(
+    JSContext* cx, const JSClass* clasp, gc::AllocKind allocKind,
+    NewObjectKind newKind = GenericObject) {
+  return NewObjectWithClassProto(cx, clasp, nullptr, allocKind, newKind);
+}
+
+inline JSObject* NewBuiltinClassInstance(
+    JSContext* cx, const JSClass* clasp,
+    NewObjectKind newKind = GenericObject) {
+  gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
+  return NewBuiltinClassInstance(cx, clasp, allocKind, newKind);
+}
+
+template <typename T>
+inline T* NewBuiltinClassInstance(JSContext* cx) {
+  JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, GenericObject);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <typename T>
+inline T* NewTenuredBuiltinClassInstance(JSContext* cx) {
+  JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, TenuredObject);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <typename T>
+inline T* NewBuiltinClassInstanceWithKind(JSContext* cx,
+                                          NewObjectKind newKind) {
+  JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <typename T>
+inline T* NewBuiltinClassInstance(JSContext* cx, gc::AllocKind allocKind,
+                                  NewObjectKind newKind = GenericObject) {
+  JSObject* obj = NewBuiltinClassInstance(cx, &T::class_, allocKind, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+// Used to optimize calls to (new Object())
+bool NewObjectScriptedCall(JSContext* cx, MutableHandleObject obj);
+
+JSObject* NewObjectWithGroupCommon(JSContext* cx, HandleObjectGroup group,
+                                   gc::AllocKind allocKind,
+                                   NewObjectKind newKind);
+
+template <typename T>
+inline T* NewObjectWithGroup(JSContext* cx, HandleObjectGroup group,
+                             gc::AllocKind allocKind,
+                             NewObjectKind newKind = GenericObject) {
+  JSObject* obj = NewObjectWithGroupCommon(cx, group, allocKind, newKind);
+  return obj ? &obj->as<T>() : nullptr;
+}
+
+template <typename T>
+inline T* NewObjectWithGroup(JSContext* cx, HandleObjectGroup group,
+                             NewObjectKind newKind = GenericObject) {
+  gc::AllocKind allocKind = gc::GetGCObjectKind(group->clasp());
+  return NewObjectWithGroup<T>(cx, group, allocKind, newKind);
+}
+
+/*
+ * As for gc::GetGCObjectKind, where numElements is a guess at the final size of
+ * the object, zero if the final size is unknown. This should only be used for
+ * objects that do not require any fixed slots.
+ */
+static inline gc::AllocKind GuessObjectGCKind(size_t numElements) {
+  if (numElements) {
+    return gc::GetGCObjectKind(numElements);
+  }
+  return gc::AllocKind::OBJECT4;
+}
+
+static inline gc::AllocKind GuessArrayGCKind(size_t numElements) {
+  if (numElements) {
+    return gc::GetGCArrayKind(numElements);
+  }
+  return gc::AllocKind::OBJECT8;
+}
+
+// Returns ESClass::Other if the value isn't an object, or if the object
+// isn't of one of the enumerated classes.  Otherwise returns the appropriate
+// class.
+inline bool GetClassOfValue(JSContext* cx, HandleValue v, ESClass* cls) {
+  if (!v.isObject()) {
+    *cls = ESClass::Other;
+    return true;
+  }
+
+  RootedObject obj(cx, &v.toObject());
+  return JS::GetBuiltinClass(cx, obj, cls);
+}
+
+extern NativeObject* InitClass(JSContext* cx, HandleObject obj,
+                               HandleObject parent_proto, const JSClass* clasp,
+                               JSNative constructor, unsigned nargs,
+                               const JSPropertySpec* ps,
+                               const JSFunctionSpec* fs,
+                               const JSPropertySpec* static_ps,
+                               const JSFunctionSpec* static_fs,
+                               NativeObject** ctorp = nullptr);
+
+MOZ_ALWAYS_INLINE const char* GetObjectClassName(JSContext* cx,
+                                                 HandleObject obj) {
+  if (obj->is<ProxyObject>()) {
+    return Proxy::className(cx, obj);
+  }
+
+  return obj->getClass()->name;
+}
+
+inline bool IsCallable(const Value& v) {
+  return v.isObject() && v.toObject().isCallable();
+}
+
+// ES6 rev 24 (2014 April 27) 7.2.5 IsConstructor
+inline bool IsConstructor(const Value& v) {
+  return v.isObject() && v.toObject().isConstructor();
+}
+
+static inline bool MaybePreserveDOMWrapper(JSContext* cx, HandleObject obj) {
+  if (!obj->getClass()->isDOMClass()) {
+    return true;
+  }
+
+  MOZ_ASSERT(cx->runtime()->preserveWrapperCallback);
+  return cx->runtime()->preserveWrapperCallback(cx, obj);
+}
+
+} /* namespace js */
+
+MOZ_ALWAYS_INLINE bool JSObject::isCallable() const {
+  if (is<JSFunction>()) {
+    return true;
+  }
+  if (is<js::ProxyObject>()) {
+    const js::ProxyObject& p = as<js::ProxyObject>();
+    return p.handler()->isCallable(const_cast<JSObject*>(this));
+  }
+  return callHook() != nullptr;
+}
+
+MOZ_ALWAYS_INLINE bool JSObject::isConstructor() const {
+  if (is<JSFunction>()) {
+    const JSFunction& fun = as<JSFunction>();
+    return fun.isConstructor();
+  }
+  if (is<js::ProxyObject>()) {
+    const js::ProxyObject& p = as<js::ProxyObject>();
+    return p.handler()->isConstructor(const_cast<JSObject*>(this));
+  }
+  return constructHook() != nullptr;
+}
+
+MOZ_ALWAYS_INLINE JSNative JSObject::callHook() const {
+  return getClass()->getCall();
+}
+
+MOZ_ALWAYS_INLINE JSNative JSObject::constructHook() const {
+  return getClass()->getConstruct();
+}
+
+#endif /* vm_JSObject_inl_h */