Add m-esr52 at 52.6.0

1 files changed, 655 insertions, 0 deletions

diff --git a/js/src/vm/ObjectGroup.h b/js/src/vm/ObjectGroup.h
new file mode 100644
index 0000000000..4e24de9f14
--- /dev/null
+++ b/js/src/vm/ObjectGroup.h
@@ -0,0 +1,655 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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_ObjectGroup_h
+#define vm_ObjectGroup_h
+
+#include "jsbytecode.h"
+#include "jsfriendapi.h"
+
+#include "ds/IdValuePair.h"
+#include "gc/Barrier.h"
+#include "js/CharacterEncoding.h"
+#include "js/GCHashTable.h"
+#include "vm/TaggedProto.h"
+#include "vm/TypeInference.h"
+
+namespace js {
+
+class TypeDescr;
+class UnboxedLayout;
+
+class PreliminaryObjectArrayWithTemplate;
+class TypeNewScript;
+class HeapTypeSet;
+class AutoClearTypeInferenceStateOnOOM;
+class CompilerConstraintList;
+
+namespace gc {
+void MergeCompartments(JSCompartment* source, JSCompartment* target);
+} // namespace gc
+
+/*
+ * The NewObjectKind allows an allocation site to specify the type properties
+ * and lifetime requirements that must be fixed at allocation time.
+ */
+enum NewObjectKind {
+    /* This is the default. Most objects are generic. */
+    GenericObject,
+
+    /*
+     * Singleton objects are treated specially by the type system. This flag
+     * ensures that the new object is automatically set up correctly as a
+     * singleton and is allocated in the tenured heap.
+     */
+    SingletonObject,
+
+    /*
+     * CrossCompartmentWrappers use the common Proxy class, but are allowed
+     * to have nursery lifetime.
+     */
+    NurseryAllocatedProxy,
+
+    /*
+     * Objects which will not benefit from being allocated in the nursery
+     * (e.g. because they are known to have a long lifetime) may be allocated
+     * with this kind to place them immediately into the tenured generation.
+     */
+    TenuredObject
+};
+
+/*
+ * Lazy object groups overview.
+ *
+ * Object groups which represent at most one JS object are constructed lazily.
+ * These include groups for native functions, standard classes, scripted
+ * functions defined at the top level of global/eval scripts, objects which
+ * dynamically become the prototype of some other object, and in some other
+ * cases. Typical web workloads often create many windows (and many copies of
+ * standard natives) and many scripts, with comparatively few non-singleton
+ * groups.
+ *
+ * We can recover the type information for the object from examining it,
+ * so don't normally track the possible types of its properties as it is
+ * updated. Property type sets for the object are only constructed when an
+ * analyzed script attaches constraints to it: the script is querying that
+ * property off the object or another which delegates to it, and the analysis
+ * information is sensitive to changes in the property's type. Future changes
+ * to the property (whether those uncovered by analysis or those occurring
+ * in the VM) will treat these properties like those of any other object group.
+ */
+
+/* Type information about an object accessed by a script. */
+class ObjectGroup : public gc::TenuredCell
+{
+    friend void gc::MergeCompartments(JSCompartment* source, JSCompartment* target);
+
+    /* Class shared by objects in this group. */
+    const Class* clasp_;
+
+    /* Prototype shared by objects in this group. */
+    GCPtr<TaggedProto> proto_;
+
+    /* Compartment shared by objects in this group. */
+    JSCompartment* compartment_;
+
+  public:
+
+    const Class* clasp() const {
+        return clasp_;
+    }
+
+    void setClasp(const Class* clasp) {
+        MOZ_ASSERT(JS::StringIsASCII(clasp->name));
+        clasp_ = clasp;
+    }
+
+    bool hasDynamicPrototype() const {
+        return proto_.isDynamic();
+    }
+
+    const GCPtr<TaggedProto>& proto() const {
+        return proto_;
+    }
+
+    GCPtr<TaggedProto>& proto() {
+        return proto_;
+    }
+
+    void setProto(TaggedProto proto);
+    void setProtoUnchecked(TaggedProto proto);
+
+    bool singleton() const {
+        return flagsDontCheckGeneration() & OBJECT_FLAG_SINGLETON;
+    }
+
+    bool lazy() const {
+        bool res = flagsDontCheckGeneration() & OBJECT_FLAG_LAZY_SINGLETON;
+        MOZ_ASSERT_IF(res, singleton());
+        return res;
+    }
+
+    JSCompartment* compartment() const { return compartment_; }
+    JSCompartment* maybeCompartment() const { return compartment(); }
+
+  private:
+    /* Flags for this group. */
+    ObjectGroupFlags flags_;
+
+    // Kinds of addendums which can be attached to ObjectGroups.
+    enum AddendumKind {
+        Addendum_None,
+
+        // When used by interpreted function, the addendum stores the
+        // canonical JSFunction object.
+        Addendum_InterpretedFunction,
+
+        // When used by the 'new' group when constructing an interpreted
+        // function, the addendum stores a TypeNewScript.
+        Addendum_NewScript,
+
+        // For some plain objects, the addendum stores a PreliminaryObjectArrayWithTemplate.
+        Addendum_PreliminaryObjects,
+
+        // When objects in this group have an unboxed representation, the
+        // addendum stores an UnboxedLayout (which might have a TypeNewScript
+        // as well, if the group is also constructed using 'new').
+        Addendum_UnboxedLayout,
+
+        // If this group is used by objects that have been converted from an
+        // unboxed representation and/or have the same allocation kind as such
+        // objects, the addendum points to that unboxed group.
+        Addendum_OriginalUnboxedGroup,
+
+        // When used by typed objects, the addendum stores a TypeDescr.
+        Addendum_TypeDescr
+    };
+
+    // If non-null, holds additional information about this object, whose
+    // format is indicated by the object's addendum kind.
+    void* addendum_;
+
+    void setAddendum(AddendumKind kind, void* addendum, bool writeBarrier = true);
+
+    AddendumKind addendumKind() const {
+        return (AddendumKind)
+            ((flags_ & OBJECT_FLAG_ADDENDUM_MASK) >> OBJECT_FLAG_ADDENDUM_SHIFT);
+    }
+
+    TypeNewScript* newScriptDontCheckGeneration() const {
+        if (addendumKind() == Addendum_NewScript)
+            return reinterpret_cast<TypeNewScript*>(addendum_);
+        return nullptr;
+    }
+
+    TypeNewScript* anyNewScript();
+    void detachNewScript(bool writeBarrier, ObjectGroup* replacement);
+
+    ObjectGroupFlags flagsDontCheckGeneration() const {
+        return flags_;
+    }
+
+  public:
+
+    inline ObjectGroupFlags flags();
+    inline void addFlags(ObjectGroupFlags flags);
+    inline void clearFlags(ObjectGroupFlags flags);
+    inline TypeNewScript* newScript();
+
+    void setNewScript(TypeNewScript* newScript) {
+        setAddendum(Addendum_NewScript, newScript);
+    }
+
+    inline PreliminaryObjectArrayWithTemplate* maybePreliminaryObjects();
+
+    PreliminaryObjectArrayWithTemplate* maybePreliminaryObjectsDontCheckGeneration() {
+        if (addendumKind() == Addendum_PreliminaryObjects)
+            return reinterpret_cast<PreliminaryObjectArrayWithTemplate*>(addendum_);
+        return nullptr;
+    }
+
+    void setPreliminaryObjects(PreliminaryObjectArrayWithTemplate* preliminaryObjects) {
+        setAddendum(Addendum_PreliminaryObjects, preliminaryObjects);
+    }
+
+    void detachPreliminaryObjects() {
+        MOZ_ASSERT(maybePreliminaryObjectsDontCheckGeneration());
+        setAddendum(Addendum_None, nullptr);
+    }
+
+    bool hasUnanalyzedPreliminaryObjects() {
+        return (newScriptDontCheckGeneration() && !newScriptDontCheckGeneration()->analyzed()) ||
+               maybePreliminaryObjectsDontCheckGeneration();
+    }
+
+    inline UnboxedLayout* maybeUnboxedLayout();
+    inline UnboxedLayout& unboxedLayout();
+
+    UnboxedLayout* maybeUnboxedLayoutDontCheckGeneration() const {
+        if (addendumKind() == Addendum_UnboxedLayout)
+            return reinterpret_cast<UnboxedLayout*>(addendum_);
+        return nullptr;
+    }
+
+    UnboxedLayout& unboxedLayoutDontCheckGeneration() const {
+        MOZ_ASSERT(addendumKind() == Addendum_UnboxedLayout);
+        return *maybeUnboxedLayoutDontCheckGeneration();
+    }
+
+    void setUnboxedLayout(UnboxedLayout* layout) {
+        setAddendum(Addendum_UnboxedLayout, layout);
+    }
+
+    ObjectGroup* maybeOriginalUnboxedGroup() const {
+        if (addendumKind() == Addendum_OriginalUnboxedGroup)
+            return reinterpret_cast<ObjectGroup*>(addendum_);
+        return nullptr;
+    }
+
+    void setOriginalUnboxedGroup(ObjectGroup* group) {
+        setAddendum(Addendum_OriginalUnboxedGroup, group);
+    }
+
+    TypeDescr* maybeTypeDescr() {
+        // Note: there is no need to sweep when accessing the type descriptor
+        // of an object, as it is strongly held and immutable.
+        if (addendumKind() == Addendum_TypeDescr)
+            return reinterpret_cast<TypeDescr*>(addendum_);
+        return nullptr;
+    }
+
+    TypeDescr& typeDescr() {
+        MOZ_ASSERT(addendumKind() == Addendum_TypeDescr);
+        return *maybeTypeDescr();
+    }
+
+    void setTypeDescr(TypeDescr* descr) {
+        setAddendum(Addendum_TypeDescr, descr);
+    }
+
+    JSFunction* maybeInterpretedFunction() {
+        // Note: as with type descriptors, there is no need to sweep when
+        // accessing the interpreted function associated with an object.
+        if (addendumKind() == Addendum_InterpretedFunction)
+            return reinterpret_cast<JSFunction*>(addendum_);
+        return nullptr;
+    }
+
+    void setInterpretedFunction(JSFunction* fun) {
+        setAddendum(Addendum_InterpretedFunction, fun);
+    }
+
+    class Property
+    {
+      public:
+        // Identifier for this property, JSID_VOID for the aggregate integer
+        // index property, or JSID_EMPTY for properties holding constraints
+        // listening to changes in the group's state.
+        GCPtrId id;
+
+        // Possible own types for this property.
+        HeapTypeSet types;
+
+        explicit Property(jsid id)
+          : id(id)
+        {}
+
+        Property(const Property& o)
+          : id(o.id.get()), types(o.types)
+        {}
+
+        static uint32_t keyBits(jsid id) { return uint32_t(JSID_BITS(id)); }
+        static jsid getKey(Property* p) { return p->id; }
+    };
+
+  private:
+    /*
+     * Properties of this object.
+     *
+     * The type sets in the properties of a group describe the possible values
+     * that can be read out of that property in actual JS objects. In native
+     * objects, property types account for plain data properties (those with a
+     * slot and no getter or setter hook) and dense elements. In typed objects
+     * and unboxed objects, property types account for object and value
+     * properties and elements in the object, and expando properties in unboxed
+     * objects.
+     *
+     * For accesses on these properties, the correspondence is as follows:
+     *
+     * 1. If the group has unknownProperties(), the possible properties and
+     *    value types for associated JSObjects are unknown.
+     *
+     * 2. Otherwise, for any |obj| in |group|, and any |id| which is a property
+     *    in |obj|, before obj->getProperty(id) the property in |group| for
+     *    |id| must reflect the result of the getProperty.
+     *
+     * There are several exceptions to this:
+     *
+     * 1. For properties of global JS objects which are undefined at the point
+     *    where the property was (lazily) generated, the property type set will
+     *    remain empty, and the 'undefined' type will only be added after a
+     *    subsequent assignment or deletion. After these properties have been
+     *    assigned a defined value, the only way they can become undefined
+     *    again is after such an assign or deletion.
+     *
+     * 2. Array lengths are special cased by the compiler and VM and are not
+     *    reflected in property types.
+     *
+     * 3. In typed objects (but not unboxed objects), the initial values of
+     *    properties (null pointers and undefined values) are not reflected in
+     *    the property types. These values are always possible when reading the
+     *    property.
+     *
+     * We establish these by using write barriers on calls to setProperty and
+     * defineProperty which are on native properties, and on any jitcode which
+     * might update the property with a new type.
+     */
+    Property** propertySet;
+  public:
+
+    inline ObjectGroup(const Class* clasp, TaggedProto proto, JSCompartment* comp,
+                       ObjectGroupFlags initialFlags);
+
+    inline bool hasAnyFlags(ObjectGroupFlags flags);
+    inline bool hasAllFlags(ObjectGroupFlags flags);
+
+    bool hasAllFlagsDontCheckGeneration(ObjectGroupFlags flags) {
+        MOZ_ASSERT((flags & OBJECT_FLAG_DYNAMIC_MASK) == flags);
+        return (this->flagsDontCheckGeneration() & flags) == flags;
+    }
+
+    inline bool unknownProperties();
+
+    bool unknownPropertiesDontCheckGeneration() {
+        MOZ_ASSERT_IF(flagsDontCheckGeneration() & OBJECT_FLAG_UNKNOWN_PROPERTIES,
+                      hasAllFlagsDontCheckGeneration(OBJECT_FLAG_DYNAMIC_MASK));
+        return !!(flagsDontCheckGeneration() & OBJECT_FLAG_UNKNOWN_PROPERTIES);
+    }
+
+    inline bool shouldPreTenure();
+
+    gc::InitialHeap initialHeap(CompilerConstraintList* constraints);
+
+    inline bool canPreTenure();
+    inline bool fromAllocationSite();
+    inline void setShouldPreTenure(ExclusiveContext* cx);
+
+    /*
+     * Get or create a property of this object. Only call this for properties which
+     * a script accesses explicitly.
+     */
+    inline HeapTypeSet* getProperty(ExclusiveContext* cx, JSObject* obj, jsid id);
+
+    /* Get a property only if it already exists. */
+    inline HeapTypeSet* maybeGetProperty(jsid id);
+
+    /*
+     * Iterate through the group's properties. getPropertyCount overapproximates
+     * in the hash case (see SET_ARRAY_SIZE in TypeInference-inl.h), and
+     * getProperty may return nullptr.
+     */
+    inline unsigned getPropertyCount();
+    inline Property* getProperty(unsigned i);
+
+    /* Helpers */
+
+    void updateNewPropertyTypes(ExclusiveContext* cx, JSObject* obj, jsid id, HeapTypeSet* types);
+    void addDefiniteProperties(ExclusiveContext* cx, Shape* shape);
+    bool matchDefiniteProperties(HandleObject obj);
+    void markPropertyNonData(ExclusiveContext* cx, JSObject* obj, jsid id);
+    void markPropertyNonWritable(ExclusiveContext* cx, JSObject* obj, jsid id);
+    void markStateChange(ExclusiveContext* cx);
+    void setFlags(ExclusiveContext* cx, ObjectGroupFlags flags);
+    void markUnknown(ExclusiveContext* cx);
+    void maybeClearNewScriptOnOOM();
+    void clearNewScript(ExclusiveContext* cx, ObjectGroup* replacement = nullptr);
+
+    void print();
+
+    inline void clearProperties();
+    void traceChildren(JSTracer* trc);
+
+    inline bool needsSweep();
+    inline void maybeSweep(AutoClearTypeInferenceStateOnOOM* oom);
+
+  private:
+    void sweep(AutoClearTypeInferenceStateOnOOM* oom);
+
+    uint32_t generation() {
+        return (flags_ & OBJECT_FLAG_GENERATION_MASK) >> OBJECT_FLAG_GENERATION_SHIFT;
+    }
+
+  public:
+    void setGeneration(uint32_t generation) {
+        MOZ_ASSERT(generation <= (OBJECT_FLAG_GENERATION_MASK >> OBJECT_FLAG_GENERATION_SHIFT));
+        flags_ &= ~OBJECT_FLAG_GENERATION_MASK;
+        flags_ |= generation << OBJECT_FLAG_GENERATION_SHIFT;
+    }
+
+    size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+
+    void finalize(FreeOp* fop);
+
+    static const JS::TraceKind TraceKind = JS::TraceKind::ObjectGroup;
+
+    static inline uint32_t offsetOfClasp() {
+        return offsetof(ObjectGroup, clasp_);
+    }
+
+    static inline uint32_t offsetOfProto() {
+        return offsetof(ObjectGroup, proto_);
+    }
+
+    static inline uint32_t offsetOfAddendum() {
+        return offsetof(ObjectGroup, addendum_);
+    }
+
+    static inline uint32_t offsetOfFlags() {
+        return offsetof(ObjectGroup, flags_);
+    }
+
+    const ObjectGroupFlags* addressOfFlags() const {
+        return &flags_;
+    }
+
+    // Get the bit pattern stored in an object's addendum when it has an
+    // original unboxed group.
+    static inline int32_t addendumOriginalUnboxedGroupValue() {
+        return Addendum_OriginalUnboxedGroup << OBJECT_FLAG_ADDENDUM_SHIFT;
+    }
+
+    inline uint32_t basePropertyCount();
+
+  private:
+    inline void setBasePropertyCount(uint32_t count);
+
+    static void staticAsserts() {
+        JS_STATIC_ASSERT(offsetof(ObjectGroup, proto_) == offsetof(js::shadow::ObjectGroup, proto));
+    }
+
+  public:
+    // Whether to make a deep cloned singleton when cloning fun.
+    static bool useSingletonForClone(JSFunction* fun);
+
+    // Whether to make a singleton when calling 'new' at script/pc.
+    static bool useSingletonForNewObject(JSContext* cx, JSScript* script, jsbytecode* pc);
+
+    // Whether to make a singleton object at an allocation site.
+    static bool useSingletonForAllocationSite(JSScript* script, jsbytecode* pc,
+                                              JSProtoKey key);
+    static bool useSingletonForAllocationSite(JSScript* script, jsbytecode* pc,
+                                              const Class* clasp);
+
+    // Static accessors for ObjectGroupCompartment NewTable.
+
+    static ObjectGroup* defaultNewGroup(ExclusiveContext* cx, const Class* clasp,
+                                        TaggedProto proto,
+                                        JSObject* associated = nullptr);
+    static ObjectGroup* lazySingletonGroup(ExclusiveContext* cx, const Class* clasp,
+                                           TaggedProto proto);
+
+    static void setDefaultNewGroupUnknown(JSContext* cx, const js::Class* clasp, JS::HandleObject obj);
+
+#ifdef DEBUG
+    static bool hasDefaultNewGroup(JSObject* proto, const Class* clasp, ObjectGroup* group);
+#endif
+
+    // Static accessors for ObjectGroupCompartment ArrayObjectTable and PlainObjectTable.
+
+    enum class NewArrayKind {
+        Normal,       // Specialize array group based on its element type.
+        CopyOnWrite,  // Make an array with copy-on-write elements.
+        UnknownIndex  // Make an array with an unknown element type.
+    };
+
+    // Create an ArrayObject or UnboxedArrayObject with the specified elements
+    // and a group specialized for the elements.
+    static JSObject* newArrayObject(ExclusiveContext* cx, const Value* vp, size_t length,
+                                    NewObjectKind newKind,
+                                    NewArrayKind arrayKind = NewArrayKind::Normal);
+
+    // Create a PlainObject or UnboxedPlainObject with the specified properties
+    // and a group specialized for those properties.
+    static JSObject* newPlainObject(ExclusiveContext* cx,
+                                    IdValuePair* properties, size_t nproperties,
+                                    NewObjectKind newKind);
+
+    // Static accessors for ObjectGroupCompartment AllocationSiteTable.
+
+    // Get a non-singleton group to use for objects created at the specified
+    // allocation site.
+    static ObjectGroup* allocationSiteGroup(JSContext* cx, JSScript* script, jsbytecode* pc,
+                                            JSProtoKey key, HandleObject proto = nullptr);
+
+    // Get a non-singleton group to use for objects created in a JSNative call.
+    static ObjectGroup* callingAllocationSiteGroup(JSContext* cx, JSProtoKey key,
+                                                   HandleObject proto = nullptr);
+
+    // Set the group or singleton-ness of an object created for an allocation site.
+    static bool
+    setAllocationSiteObjectGroup(JSContext* cx, HandleScript script, jsbytecode* pc,
+                                 HandleObject obj, bool singleton);
+
+    static ArrayObject* getOrFixupCopyOnWriteObject(JSContext* cx, HandleScript script,
+                                                    jsbytecode* pc);
+    static ArrayObject* getCopyOnWriteObject(JSScript* script, jsbytecode* pc);
+
+    // Returns false if not found.
+    static bool findAllocationSite(JSContext* cx, ObjectGroup* group,
+                                   JSScript** script, uint32_t* offset);
+
+  private:
+    static ObjectGroup* defaultNewGroup(JSContext* cx, JSProtoKey key);
+};
+
+// Structure used to manage the groups in a compartment.
+class ObjectGroupCompartment
+{
+    friend class ObjectGroup;
+
+    class NewTable;
+
+    // Set of default 'new' or lazy groups in the compartment.
+    NewTable* defaultNewTable;
+    NewTable* lazyTable;
+
+    struct ArrayObjectKey;
+    using ArrayObjectTable = js::GCRekeyableHashMap<ArrayObjectKey,
+                                                    ReadBarrieredObjectGroup,
+                                                    ArrayObjectKey,
+                                                    SystemAllocPolicy>;
+
+    struct PlainObjectKey;
+    struct PlainObjectEntry;
+    struct PlainObjectTableSweepPolicy {
+        static bool needsSweep(PlainObjectKey* key, PlainObjectEntry* entry);
+    };
+    using PlainObjectTable = JS::GCHashMap<PlainObjectKey,
+                                           PlainObjectEntry,
+                                           PlainObjectKey,
+                                           SystemAllocPolicy,
+                                           PlainObjectTableSweepPolicy>;
+
+    // Tables for managing groups common to the contents of large script
+    // singleton objects and JSON objects. These are vanilla ArrayObjects and
+    // PlainObjects, so we distinguish the groups of different ones by looking
+    // at the types of their properties.
+    //
+    // All singleton/JSON arrays which have the same prototype, are homogenous
+    // and of the same element type will share a group. All singleton/JSON
+    // objects which have the same shape and property types will also share a
+    // group. We don't try to collate arrays or objects with type mismatches.
+    ArrayObjectTable* arrayObjectTable;
+    PlainObjectTable* plainObjectTable;
+
+    struct AllocationSiteKey;
+    class AllocationSiteTable;
+
+    // Table for referencing types of objects keyed to an allocation site.
+    AllocationSiteTable* allocationSiteTable;
+
+  public:
+    struct NewEntry;
+
+    ObjectGroupCompartment();
+    ~ObjectGroupCompartment();
+
+    void replaceAllocationSiteGroup(JSScript* script, jsbytecode* pc,
+                                    JSProtoKey kind, ObjectGroup* group);
+
+    void removeDefaultNewGroup(const Class* clasp, TaggedProto proto, JSObject* associated);
+    void replaceDefaultNewGroup(const Class* clasp, TaggedProto proto, JSObject* associated,
+                                ObjectGroup* group);
+
+    static ObjectGroup* makeGroup(ExclusiveContext* cx, const Class* clasp,
+                                  Handle<TaggedProto> proto,
+                                  ObjectGroupFlags initialFlags = 0);
+
+    void addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf,
+                                size_t* allocationSiteTables,
+                                size_t* arrayGroupTables,
+                                size_t* plainObjectGroupTables,
+                                size_t* compartmentTables);
+
+    void clearTables();
+
+    void sweep(FreeOp* fop);
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+    void checkTablesAfterMovingGC() {
+        checkNewTableAfterMovingGC(defaultNewTable);
+        checkNewTableAfterMovingGC(lazyTable);
+    }
+#endif
+
+    void fixupTablesAfterMovingGC() {
+        fixupNewTableAfterMovingGC(defaultNewTable);
+        fixupNewTableAfterMovingGC(lazyTable);
+    }
+
+  private:
+#ifdef JSGC_HASH_TABLE_CHECKS
+    void checkNewTableAfterMovingGC(NewTable* table);
+#endif
+
+    void fixupNewTableAfterMovingGC(NewTable* table);
+};
+
+PlainObject*
+NewPlainObjectWithProperties(ExclusiveContext* cx, IdValuePair* properties, size_t nproperties,
+                             NewObjectKind newKind);
+
+bool
+CombineArrayElementTypes(ExclusiveContext* cx, JSObject* newObj,
+                         const Value* compare, size_t ncompare);
+
+bool
+CombinePlainObjectPropertyTypes(ExclusiveContext* cx, JSObject* newObj,
+                                const Value* compare, size_t ncompare);
+
+} // namespace js
+
+#endif /* vm_ObjectGroup_h */