Remove Unboxed Object code from /vm, Part 3.

18 files changed, 13 insertions, 1560 deletions

diff --git a/js/src/jsarray.cpp b/js/src/jsarray.cpp
index 5854fda4c..ec65bce64 100644
--- a/js/src/jsarray.cpp
+++ b/js/src/jsarray.cpp
@@ -45,7 +45,6 @@
 #include "vm/Caches-inl.h"
 #include "vm/Interpreter-inl.h"
 #include "vm/NativeObject-inl.h"
-#include "vm/UnboxedObject-inl.h"
 
 using namespace js;
 using namespace js::gc;
diff --git a/js/src/jscompartment.h b/js/src/jscompartment.h
index 98c8fe200..83c15da3b 100644
--- a/js/src/jscompartment.h
+++ b/js/src/jscompartment.h
@@ -529,9 +529,6 @@ struct JSCompartment
     // table manages references from such typed objects to their buffers.
     js::ObjectWeakMap* lazyArrayBuffers;
 
-    // All unboxed layouts in the compartment.
-    mozilla::LinkedList<js::UnboxedLayout> unboxedLayouts;
-
     // WebAssembly state for the compartment.
     js::wasm::Compartment wasm;
 
diff --git a/js/src/jsfriendapi.cpp b/js/src/jsfriendapi.cpp
index 1fd9d1d28..5baba0beb 100644
--- a/js/src/jsfriendapi.cpp
+++ b/js/src/jsfriendapi.cpp
@@ -269,7 +269,7 @@ js::GetBuiltinClass(JSContext* cx, HandleObject obj, ESClass* cls)
     if (MOZ_UNLIKELY(obj->is<ProxyObject>()))
         return Proxy::getBuiltinClass(cx, obj, cls);
 
-    if (obj->is<PlainObject>() || obj->is<UnboxedPlainObject>())
+    if (obj->is<PlainObject>())
         *cls = ESClass::Object;
     else if (obj->is<ArrayObject>())
         *cls = ESClass::Array;
diff --git a/js/src/jsobj.cpp b/js/src/jsobj.cpp
index deaa1d53e..58988739b 100644
--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -54,7 +54,6 @@
 #include "vm/RegExpStaticsObject.h"
 #include "vm/Shape.h"
 #include "vm/TypedArrayCommon.h"
-#include "vm/UnboxedObject-inl.h"
 
 #include "jsatominlines.h"
 #include "jsboolinlines.h"
diff --git a/js/src/jsobjinlines.h b/js/src/jsobjinlines.h
index 26f9eacce..b1d817bca 100644
--- a/js/src/jsobjinlines.h
+++ b/js/src/jsobjinlines.h
@@ -32,19 +32,6 @@
 #include "vm/ShapedObject-inl.h"
 #include "vm/TypeInference-inl.h"
 
-namespace js {
-
-// This is needed here for ensureShape() below.
-inline bool
-MaybeConvertUnboxedObjectToNative(ExclusiveContext* cx, JSObject* obj)
-{
-    if (obj->is<UnboxedPlainObject>())
-        return UnboxedPlainObject::convertToNative(cx->asJSContext(), obj);
-    return true;
-}
-
-} // namespace js
-
 inline js::Shape*
 JSObject::maybeShape() const
 {
@@ -57,8 +44,6 @@ JSObject::maybeShape() const
 inline js::Shape*
 JSObject::ensureShape(js::ExclusiveContext* cx)
 {
-    if (!js::MaybeConvertUnboxedObjectToNative(cx, this))
-        return nullptr;
     js::Shape* shape = maybeShape();
     MOZ_ASSERT(shape);
     return shape;
diff --git a/js/src/moz.build b/js/src/moz.build
index 888741138..eb30866c8 100644
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -355,7 +355,6 @@ UNIFIED_SOURCES += [
     'vm/UbiNode.cpp',
     'vm/UbiNodeCensus.cpp',
     'vm/UbiNodeShortestPaths.cpp',
-    'vm/UnboxedObject.cpp',
     'vm/Unicode.cpp',
     'vm/Value.cpp',
     'vm/WeakMapPtr.cpp',
diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index 74a1ef3e9..0f83c3435 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -4970,11 +4970,6 @@ js::NewObjectOperationWithTemplate(JSContext* cx, HandleObject templateObject)
 
     NewObjectKind newKind = templateObject->group()->shouldPreTenure() ? TenuredObject : GenericObject;
 
-    if (templateObject->group()->maybeUnboxedLayout()) {
-        RootedObjectGroup group(cx, templateObject->group());
-        return UnboxedPlainObject::create(cx, group, newKind);
-    }
-
     JSObject* obj = CopyInitializerObject(cx, templateObject.as<PlainObject>(), newKind);
     if (!obj)
         return nullptr;
diff --git a/js/src/vm/NativeObject.cpp b/js/src/vm/NativeObject.cpp
index 21f73f4a9..a3f28653a 100644
--- a/js/src/vm/NativeObject.cpp
+++ b/js/src/vm/NativeObject.cpp
@@ -390,33 +390,6 @@ NativeObject::setLastPropertyMakeNonNative(Shape* shape)
     shape_ = shape;
 }
 
-void
-NativeObject::setLastPropertyMakeNative(ExclusiveContext* cx, Shape* shape)
-{
-    MOZ_ASSERT(getClass()->isNative());
-    MOZ_ASSERT(shape->getObjectClass()->isNative());
-    MOZ_ASSERT(!shape->inDictionary());
-
-    // This method is used to convert unboxed objects into native objects. In
-    // this case, the shape_ field was previously used to store other data and
-    // this should be treated as an initialization.
-    shape_.init(shape);
-
-    slots_ = nullptr;
-    elements_ = emptyObjectElements;
-
-    size_t oldSpan = shape->numFixedSlots();
-    size_t newSpan = shape->slotSpan();
-
-    initializeSlotRange(0, oldSpan);
-
-    // A failure at this point will leave the object as a mutant, and we
-    // can't recover.
-    AutoEnterOOMUnsafeRegion oomUnsafe;
-    if (oldSpan != newSpan && !updateSlotsForSpan(cx, oldSpan, newSpan))
-        oomUnsafe.crash("NativeObject::setLastPropertyMakeNative");
-}
-
 bool
 NativeObject::setSlotSpan(ExclusiveContext* cx, uint32_t span)
 {
diff --git a/js/src/vm/NativeObject.h b/js/src/vm/NativeObject.h
index da4f873a6..d9d8b8aec 100644
--- a/js/src/vm/NativeObject.h
+++ b/js/src/vm/NativeObject.h
@@ -470,11 +470,6 @@ class NativeObject : public ShapedObject
     // that are (temporarily) inconsistent.
     void setLastPropertyMakeNonNative(Shape* shape);
 
-    // As for setLastProperty(), but changes the class associated with the
-    // object to a native one. The object's type has already been changed, and
-    // this brings the shape into sync with it.
-    void setLastPropertyMakeNative(ExclusiveContext* cx, Shape* shape);
-
     // Newly-created TypedArrays that map a SharedArrayBuffer are
     // marked as shared by giving them an ObjectElements that has the
     // ObjectElements::SHARED_MEMORY flag set.
diff --git a/js/src/vm/ObjectGroup-inl.h b/js/src/vm/ObjectGroup-inl.h
index 9074f4d97..d41343be6 100644
--- a/js/src/vm/ObjectGroup-inl.h
+++ b/js/src/vm/ObjectGroup-inl.h
@@ -108,20 +108,6 @@ ObjectGroup::maybePreliminaryObjects()
     return maybePreliminaryObjectsDontCheckGeneration();
 }
 
-inline UnboxedLayout*
-ObjectGroup::maybeUnboxedLayout()
-{
-    maybeSweep(nullptr);
-    return maybeUnboxedLayoutDontCheckGeneration();
-}
-
-inline UnboxedLayout&
-ObjectGroup::unboxedLayout()
-{
-    maybeSweep(nullptr);
-    return unboxedLayoutDontCheckGeneration();
-}
-
 } // namespace js
 
 #endif /* vm_ObjectGroup_inl_h */
diff --git a/js/src/vm/ObjectGroup.cpp b/js/src/vm/ObjectGroup.cpp
index 63ac33eea..676792379 100644
--- a/js/src/vm/ObjectGroup.cpp
+++ b/js/src/vm/ObjectGroup.cpp
@@ -18,11 +18,10 @@
 #include "vm/ArrayObject.h"
 #include "vm/Shape.h"
 #include "vm/TaggedProto.h"
-#include "vm/UnboxedObject.h"
 
 #include "jsobjinlines.h"
 
-#include "vm/UnboxedObject-inl.h"
+#include "vm/NativeObject-inl.h"
 
 using namespace js;
 
@@ -56,7 +55,6 @@ ObjectGroup::finalize(FreeOp* fop)
     if (newScriptDontCheckGeneration())
         newScriptDontCheckGeneration()->clear();
     fop->delete_(newScriptDontCheckGeneration());
-    fop->delete_(maybeUnboxedLayoutDontCheckGeneration());
     if (maybePreliminaryObjectsDontCheckGeneration())
         maybePreliminaryObjectsDontCheckGeneration()->clear();
     fop->delete_(maybePreliminaryObjectsDontCheckGeneration());
@@ -83,8 +81,6 @@ ObjectGroup::sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
     size_t n = 0;
     if (TypeNewScript* newScript = newScriptDontCheckGeneration())
         n += newScript->sizeOfIncludingThis(mallocSizeOf);
-    if (UnboxedLayout* layout = maybeUnboxedLayoutDontCheckGeneration())
-        n += layout->sizeOfIncludingThis(mallocSizeOf);
     return n;
 }
 
@@ -530,8 +526,7 @@ ObjectGroup::defaultNewGroup(ExclusiveContext* cx, const Class* clasp,
     if (p) {
         ObjectGroup* group = p->group;
         MOZ_ASSERT_IF(clasp, group->clasp() == clasp);
-        MOZ_ASSERT_IF(!clasp, group->clasp() == &PlainObject::class_ ||
-                              group->clasp() == &UnboxedPlainObject::class_);
+        MOZ_ASSERT_IF(!clasp, group->clasp() == &PlainObject::class_);
         MOZ_ASSERT(group->proto() == proto);
         return group;
     }
@@ -971,46 +966,6 @@ js::CombinePlainObjectPropertyTypes(ExclusiveContext* cx, JSObject* newObj,
                 }
             }
         }
-    } else if (newObj->is<UnboxedPlainObject>()) {
-        const UnboxedLayout& layout = newObj->as<UnboxedPlainObject>().layout();
-        const int32_t* traceList = layout.traceList();
-        if (!traceList)
-            return true;
-
-        uint8_t* newData = newObj->as<UnboxedPlainObject>().data();
-        uint8_t* oldData = oldObj->as<UnboxedPlainObject>().data();
-
-        for (; *traceList != -1; traceList++) {}
-        traceList++;
-        for (; *traceList != -1; traceList++) {
-            JSObject* newInnerObj = *reinterpret_cast<JSObject**>(newData + *traceList);
-            JSObject* oldInnerObj = *reinterpret_cast<JSObject**>(oldData + *traceList);
-
-            if (!newInnerObj || !oldInnerObj || SameGroup(oldInnerObj, newInnerObj))
-                continue;
-
-            if (!GiveObjectGroup(cx, newInnerObj, oldInnerObj))
-                return false;
-
-            if (SameGroup(oldInnerObj, newInnerObj))
-                continue;
-
-            if (!GiveObjectGroup(cx, oldInnerObj, newInnerObj))
-                return false;
-
-            if (SameGroup(oldInnerObj, newInnerObj)) {
-                for (size_t i = 1; i < ncompare; i++) {
-                    if (compare[i].isObject() && SameGroup(&compare[i].toObject(), newObj)) {
-                        uint8_t* otherData = compare[i].toObject().as<UnboxedPlainObject>().data();
-                        JSObject* otherInnerObj = *reinterpret_cast<JSObject**>(otherData + *traceList);
-                        if (otherInnerObj && !SameGroup(otherInnerObj, newInnerObj)) {
-                            if (!GiveObjectGroup(cx, otherInnerObj, newInnerObj))
-                                return false;
-                        }
-                    }
-                }
-            }
-        }
     }
 
     return true;
@@ -1234,12 +1189,6 @@ ObjectGroup::newPlainObject(ExclusiveContext* cx, IdValuePair* properties, size_
 
     RootedObjectGroup group(cx, p->value().group);
 
-    // Watch for existing groups which now use an unboxed layout.
-    if (group->maybeUnboxedLayout()) {
-        MOZ_ASSERT(group->unboxedLayout().properties().length() == nproperties);
-        return UnboxedPlainObject::createWithProperties(cx, group, newKind, properties);
-    }
-
     // Update property types according to the properties we are about to add.
     // Do this before we do anything which can GC, which might move or remove
     // this table entry.
diff --git a/js/src/vm/ObjectGroup.h b/js/src/vm/ObjectGroup.h
index 553cb8366..bf8398742 100644
--- a/js/src/vm/ObjectGroup.h
+++ b/js/src/vm/ObjectGroup.h
@@ -20,7 +20,6 @@
 namespace js {
 
 class TypeDescr;
-class UnboxedLayout;
 
 class PreliminaryObjectArrayWithTemplate;
 class TypeNewScript;
@@ -154,11 +153,6 @@ class ObjectGroup : public gc::TenuredCell
         // 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.
@@ -225,24 +219,6 @@ class ObjectGroup : public gc::TenuredCell
                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_);
@@ -511,8 +487,8 @@ class ObjectGroup : public gc::TenuredCell
                                        NewObjectKind newKind,
                                        NewArrayKind arrayKind = NewArrayKind::Normal);
 
-    // Create a PlainObject or UnboxedPlainObject with the specified properties
-    // and a group specialized for those properties.
+    // Create a PlainObject with the specified properties and a group specialized
+    // for those properties.
     static JSObject* newPlainObject(ExclusiveContext* cx,
                                     IdValuePair* properties, size_t nproperties,
                                     NewObjectKind newKind);
diff --git a/js/src/vm/ReceiverGuard.cpp b/js/src/vm/ReceiverGuard.cpp
index e37bf8ee5..e95e8a208 100644
--- a/js/src/vm/ReceiverGuard.cpp
+++ b/js/src/vm/ReceiverGuard.cpp
@@ -15,11 +15,7 @@ ReceiverGuard::ReceiverGuard(JSObject* obj)
   : group(nullptr), shape(nullptr)
 {
     if (obj) {
-        if (obj->is<UnboxedPlainObject>()) {
-            group = obj->group();
-            if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando())
-                shape = expando->lastProperty();
-        } else if (obj->is<TypedObject>()) {
+        if (obj->is<TypedObject>()) {
             group = obj->group();
         } else {
             shape = obj->maybeShape();
@@ -32,9 +28,7 @@ ReceiverGuard::ReceiverGuard(ObjectGroup* group, Shape* shape)
 {
     if (group) {
         const Class* clasp = group->clasp();
-        if (clasp == &UnboxedPlainObject::class_) {
-            // Keep both group and shape.
-        } else if (IsTypedObjectClass(clasp)) {
+        if (IsTypedObjectClass(clasp)) {
             this->shape = nullptr;
         } else {
             this->group = nullptr;
@@ -45,10 +39,6 @@ ReceiverGuard::ReceiverGuard(ObjectGroup* group, Shape* shape)
 /* static */ int32_t
 HeapReceiverGuard::keyBits(JSObject* obj)
 {
-    if (obj->is<UnboxedPlainObject>()) {
-        // Both the group and shape need to be guarded for unboxed plain objects.
-        return obj->as<UnboxedPlainObject>().maybeExpando() ? 0 : 1;
-    }
     if (obj->is<TypedObject>()) {
         // Only the group needs to be guarded for typed objects.
         return 2;
diff --git a/js/src/vm/TypeInference-inl.h b/js/src/vm/TypeInference-inl.h
index da47fa898..2af252cea 100644
--- a/js/src/vm/TypeInference-inl.h
+++ b/js/src/vm/TypeInference-inl.h
@@ -23,7 +23,6 @@
 #include "vm/SharedArrayObject.h"
 #include "vm/StringObject.h"
 #include "vm/TypedArrayObject.h"
-#include "vm/UnboxedObject.h"
 
 #include "jscntxtinlines.h"
 
@@ -285,10 +284,6 @@ TypeIdString(jsid id)
  */
 struct AutoEnterAnalysis
 {
-    // For use when initializing an UnboxedLayout.  The UniquePtr's destructor
-    // must run when GC is not suppressed.
-    UniquePtr<UnboxedLayout> unboxedLayoutToCleanUp;
-
     // Prevent GC activity in the middle of analysis.
     gc::AutoSuppressGC suppressGC;
 
diff --git a/js/src/vm/TypeInference.cpp b/js/src/vm/TypeInference.cpp
index 0551e2c58..26ade2948 100644
--- a/js/src/vm/TypeInference.cpp
+++ b/js/src/vm/TypeInference.cpp
@@ -35,7 +35,6 @@
 #include "vm/Opcodes.h"
 #include "vm/Shape.h"
 #include "vm/Time.h"
-#include "vm/UnboxedObject.h"
 
 #include "jsatominlines.h"
 #include "jsscriptinlines.h"
@@ -297,9 +296,6 @@ js::ObjectGroupHasProperty(JSContext* cx, ObjectGroup* group, jsid id, const Val
                         return true;
                 }
             }
-            JSObject* obj = &value.toObject();
-            if (!obj->hasLazyGroup() && obj->group()->maybeOriginalUnboxedGroup())
-                return true;
         }
 
         if (!types->hasType(type)) {
@@ -1944,33 +1940,6 @@ class ConstraintDataFreezeObjectForTypedArrayData
     }
 };
 
-// Constraint which triggers recompilation if an unboxed object in some group
-// is converted to a native object.
-class ConstraintDataFreezeObjectForUnboxedConvertedToNative
-{
-  public:
-    ConstraintDataFreezeObjectForUnboxedConvertedToNative()
-    {}
-
-    const char* kind() { return "freezeObjectForUnboxedConvertedToNative"; }
-
-    bool invalidateOnNewType(TypeSet::Type type) { return false; }
-    bool invalidateOnNewPropertyState(TypeSet* property) { return false; }
-    bool invalidateOnNewObjectState(ObjectGroup* group) {
-        return group->unboxedLayout().nativeGroup() != nullptr;
-    }
-
-    bool constraintHolds(JSContext* cx,
-                         const HeapTypeSetKey& property, TemporaryTypeSet* expected)
-    {
-        return !invalidateOnNewObjectState(property.object()->maybeGroup());
-    }
-
-    bool shouldSweep() { return false; }
-
-    JSCompartment* maybeCompartment() { return nullptr; }
-};
-
 } /* anonymous namespace */
 
 void
@@ -2505,8 +2474,6 @@ TemporaryTypeSet::propertyNeedsBarrier(CompilerConstraintList* constraints, jsid
 bool
 js::ClassCanHaveExtraProperties(const Class* clasp)
 {
-    if (clasp == &UnboxedPlainObject::class_)
-        return false;
     return clasp->getResolve()
         || clasp->getOpsLookupProperty()
         || clasp->getOpsGetProperty()
@@ -2805,15 +2772,6 @@ js::AddTypePropertyId(ExclusiveContext* cx, ObjectGroup* group, JSObject* obj, j
     // from acquiring the fully initialized group.
     if (group->newScript() && group->newScript()->initializedGroup())
         AddTypePropertyId(cx, group->newScript()->initializedGroup(), nullptr, id, type);
-
-    // Maintain equivalent type information for unboxed object groups and their
-    // corresponding native group. Since type sets might contain the unboxed
-    // group but not the native group, this ensures optimizations based on the
-    // unboxed group are valid for the native group.
-    if (group->maybeUnboxedLayout() && group->maybeUnboxedLayout()->nativeGroup())
-        AddTypePropertyId(cx, group->maybeUnboxedLayout()->nativeGroup(), nullptr, id, type);
-    if (ObjectGroup* unboxedGroup = group->maybeOriginalUnboxedGroup())
-        AddTypePropertyId(cx, unboxedGroup, nullptr, id, type);
 }
 
 void
@@ -2885,12 +2843,6 @@ ObjectGroup::setFlags(ExclusiveContext* cx, ObjectGroupFlags flags)
     // acquired properties analysis.
     if (newScript() && newScript()->initializedGroup())
         newScript()->initializedGroup()->setFlags(cx, flags);
-
-    // Propagate flag changes between unboxed and corresponding native groups.
-    if (maybeUnboxedLayout() && maybeUnboxedLayout()->nativeGroup())
-        maybeUnboxedLayout()->nativeGroup()->setFlags(cx, flags);
-    if (ObjectGroup* unboxedGroup = maybeOriginalUnboxedGroup())
-        unboxedGroup->setFlags(cx, flags);
 }
 
 void
@@ -2923,13 +2875,6 @@ ObjectGroup::markUnknown(ExclusiveContext* cx)
             prop->types.setNonDataProperty(cx);
         }
     }
-
-    if (ObjectGroup* unboxedGroup = maybeOriginalUnboxedGroup())
-        MarkObjectGroupUnknownProperties(cx, unboxedGroup);
-    if (maybeUnboxedLayout() && maybeUnboxedLayout()->nativeGroup())
-        MarkObjectGroupUnknownProperties(cx, maybeUnboxedLayout()->nativeGroup());
-    if (ObjectGroup* unboxedGroup = maybeOriginalUnboxedGroup())
-        MarkObjectGroupUnknownProperties(cx, unboxedGroup);
 }
 
 TypeNewScript*
@@ -2937,8 +2882,6 @@ ObjectGroup::anyNewScript()
 {
     if (newScript())
         return newScript();
-    if (maybeUnboxedLayout())
-        return unboxedLayout().newScript();
     return nullptr;
 }
 
@@ -2968,10 +2911,7 @@ ObjectGroup::detachNewScript(bool writeBarrier, ObjectGroup* replacement)
         MOZ_ASSERT(!replacement);
     }
 
-    if (this->newScript())
-        setAddendum(Addendum_None, nullptr, writeBarrier);
-    else
-        unboxedLayout().setNewScript(nullptr, writeBarrier);
+    setAddendum(Addendum_None, nullptr, writeBarrier);
 }
 
 void
@@ -3451,22 +3391,6 @@ PreliminaryObjectArray::sweep()
     for (size_t i = 0; i < COUNT; i++) {
         JSObject** ptr = &objects[i];
         if (*ptr && IsAboutToBeFinalizedUnbarriered(ptr)) {
-            // Before we clear this reference, change the object's group to the
-            // Object.prototype group. This is done to ensure JSObject::finalize
-            // sees a NativeObject Class even if we change the current group's
-            // Class to one of the unboxed object classes in the meantime. If
-            // the compartment's global is dead, we don't do anything as the
-            // group's Class is not going to change in that case.
-            JSObject* obj = *ptr;
-            GlobalObject* global = obj->compartment()->unsafeUnbarrieredMaybeGlobal();
-            if (global && !obj->isSingleton()) {
-                JSObject* objectProto = GetBuiltinPrototypePure(global, JSProto_Object);
-                obj->setGroup(objectProto->groupRaw());
-                MOZ_ASSERT(obj->is<NativeObject>());
-                MOZ_ASSERT(obj->getClass() == objectProto->getClass());
-                MOZ_ASSERT(!obj->getClass()->hasFinalize());
-            }
-
             *ptr = nullptr;
         }
     }
@@ -3566,16 +3490,11 @@ PreliminaryObjectArrayWithTemplate::maybeAnalyze(ExclusiveContext* cx, ObjectGro
         }
     }
 
-    if (group->maybeUnboxedLayout())
-        return;
-
-    if (shape()) {
-        // We weren't able to use an unboxed layout, but since the preliminary
-        // objects still reflect the template object's properties, and all
-        // objects in the future will be created with those properties, the
-        // properties can be marked as definite for objects in the group.
-        group->addDefiniteProperties(cx, shape());
-    }
+    // Since the preliminary objects still reflect the template object's
+    // properties, and all objects in the future will be created with those
+    // properties, the properties can be marked as definitive for objects in
+    // the group.
+    group->addDefiniteProperties(cx, shape());
 }
 
 /////////////////////////////////////////////////////////////////////
@@ -3589,7 +3508,6 @@ TypeNewScript::make(JSContext* cx, ObjectGroup* group, JSFunction* fun)
 {
     MOZ_ASSERT(cx->zone()->types.activeAnalysis);
     MOZ_ASSERT(!group->newScript());
-    MOZ_ASSERT(!group->maybeUnboxedLayout());
 
     // rollbackPartiallyInitializedObjects expects function_ to be
     // canonicalized.
@@ -3852,27 +3770,6 @@ TypeNewScript::maybeAnalyze(JSContext* cx, ObjectGroup* group, bool* regenerate,
     js_delete(preliminaryObjects);
     preliminaryObjects = nullptr;
 
-    if (group->maybeUnboxedLayout()) {
-        // An unboxed layout was constructed for the group, and this has already
-        // been hooked into it.
-        MOZ_ASSERT(group->unboxedLayout().newScript() == this);
-        destroyNewScript.group = nullptr;
-
-        // Clear out the template object, which is not used for TypeNewScripts
-        // with an unboxed layout. Currently it is a mutant object with a
-        // non-native group and native shape, so make it safe for GC by changing
-        // its group to the default for its prototype.
-        AutoEnterOOMUnsafeRegion oomUnsafe;
-        ObjectGroup* plainGroup = ObjectGroup::defaultNewGroup(cx, &PlainObject::class_,
-                                                               group->proto());
-        if (!plainGroup)
-            oomUnsafe.crash("TypeNewScript::maybeAnalyze");
-        templateObject_->setGroup(plainGroup);
-        templateObject_ = nullptr;
-
-        return true;
-    }
-
     if (prefixShape->slotSpan() == templateObject()->slotSpan()) {
         // The definite properties analysis found exactly the properties that
         // are held in common by the preliminary objects. No further analysis
@@ -3968,12 +3865,6 @@ TypeNewScript::rollbackPartiallyInitializedObjects(JSContext* cx, ObjectGroup* g
             continue;
         }
 
-        if (thisv.toObject().is<UnboxedPlainObject>()) {
-            AutoEnterOOMUnsafeRegion oomUnsafe;
-            if (!UnboxedPlainObject::convertToNative(cx, &thisv.toObject()))
-                oomUnsafe.crash("rollbackPartiallyInitializedObjects");
-        }
-
         // Found a matching frame.
         RootedPlainObject obj(cx, &thisv.toObject().as<PlainObject>());
 
@@ -4167,12 +4058,6 @@ ConstraintTypeSet::sweep(Zone* zone, AutoClearTypeInferenceStateOnOOM& oom)
                 // Object sets containing objects with unknown properties might
                 // not be complete. Mark the type set as unknown, which it will
                 // be treated as during Ion compilation.
-                //
-                // Note that we don't have to do this when the type set might
-                // be missing the native group corresponding to an unboxed
-                // object group. In this case, the native group points to the
-                // unboxed object group via its addendum, so as long as objects
-                // with either group exist, neither group will be finalized.
                 flags |= TYPE_FLAG_ANYOBJECT;
                 clearObjects();
                 objectCount = 0;
@@ -4256,21 +4141,6 @@ ObjectGroup::sweep(AutoClearTypeInferenceStateOnOOM* oom)
     Maybe<AutoClearTypeInferenceStateOnOOM> fallbackOOM;
     EnsureHasAutoClearTypeInferenceStateOnOOM(oom, zone(), fallbackOOM);
 
-    if (maybeUnboxedLayout()) {
-        // Remove unboxed layouts that are about to be finalized from the
-        // compartment wide list while we are still on the main thread.
-        ObjectGroup* group = this;
-        if (IsAboutToBeFinalizedUnbarriered(&group))
-            unboxedLayout().detachFromCompartment();
-
-        if (unboxedLayout().newScript())
-            unboxedLayout().newScript()->sweep();
-
-        // Discard constructor code to avoid holding onto ExecutablePools.
-        if (zone()->isGCCompacting())
-            unboxedLayout().setConstructorCode(nullptr);
-    }
-
     if (maybePreliminaryObjects())
         maybePreliminaryObjects()->sweep();
 
diff --git a/js/src/vm/UnboxedObject-inl.h b/js/src/vm/UnboxedObject-inl.h
deleted file mode 100644
index c1468a5b1..000000000
--- a/js/src/vm/UnboxedObject-inl.h
+++ /dev/null
@@ -1,177 +0,0 @@
-/* -*- 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_UnboxedObject_inl_h
-#define vm_UnboxedObject_inl_h
-
-#include "vm/UnboxedObject.h"
-
-#include "gc/StoreBuffer-inl.h"
-#include "vm/ArrayObject-inl.h"
-#include "vm/NativeObject-inl.h"
-
-namespace js {
-
-static inline Value
-GetUnboxedValue(uint8_t* p, JSValueType type, bool maybeUninitialized)
-{
-    switch (type) {
-      case JSVAL_TYPE_BOOLEAN:
-        return BooleanValue(*p != 0);
-
-      case JSVAL_TYPE_INT32:
-        return Int32Value(*reinterpret_cast<int32_t*>(p));
-
-      case JSVAL_TYPE_DOUBLE: {
-        // During unboxed plain object creation, non-GC thing properties are
-        // left uninitialized. This is normally fine, since the properties will
-        // be filled in shortly, but if they are read before that happens we
-        // need to make sure that doubles are canonical.
-        double d = *reinterpret_cast<double*>(p);
-        if (maybeUninitialized)
-            return DoubleValue(JS::CanonicalizeNaN(d));
-        return DoubleValue(d);
-      }
-
-      case JSVAL_TYPE_STRING:
-        return StringValue(*reinterpret_cast<JSString**>(p));
-
-      case JSVAL_TYPE_OBJECT:
-        return ObjectOrNullValue(*reinterpret_cast<JSObject**>(p));
-
-      default:
-        MOZ_CRASH("Invalid type for unboxed value");
-    }
-}
-
-static inline void
-SetUnboxedValueNoTypeChange(JSObject* unboxedObject,
-                            uint8_t* p, JSValueType type, const Value& v,
-                            bool preBarrier)
-{
-    switch (type) {
-      case JSVAL_TYPE_BOOLEAN:
-        *p = v.toBoolean();
-        return;
-
-      case JSVAL_TYPE_INT32:
-        *reinterpret_cast<int32_t*>(p) = v.toInt32();
-        return;
-
-      case JSVAL_TYPE_DOUBLE:
-        *reinterpret_cast<double*>(p) = v.toNumber();
-        return;
-
-      case JSVAL_TYPE_STRING: {
-        MOZ_ASSERT(!IsInsideNursery(v.toString()));
-        JSString** np = reinterpret_cast<JSString**>(p);
-        if (preBarrier)
-            JSString::writeBarrierPre(*np);
-        *np = v.toString();
-        return;
-      }
-
-      case JSVAL_TYPE_OBJECT: {
-        JSObject** np = reinterpret_cast<JSObject**>(p);
-
-        // Manually trigger post barriers on the whole object. If we treat
-        // the pointer as a HeapPtrObject we will get confused later if the
-        // object is converted to its native representation.
-        JSObject* obj = v.toObjectOrNull();
-        if (IsInsideNursery(obj) && !IsInsideNursery(unboxedObject)) {
-            JSRuntime* rt = unboxedObject->runtimeFromMainThread();
-            rt->gc.storeBuffer.putWholeCell(unboxedObject);
-        }
-
-        if (preBarrier)
-            JSObject::writeBarrierPre(*np);
-        *np = obj;
-        return;
-      }
-
-      default:
-        MOZ_CRASH("Invalid type for unboxed value");
-    }
-}
-
-static inline bool
-SetUnboxedValue(ExclusiveContext* cx, JSObject* unboxedObject, jsid id,
-                uint8_t* p, JSValueType type, const Value& v, bool preBarrier)
-{
-    switch (type) {
-      case JSVAL_TYPE_BOOLEAN:
-        if (v.isBoolean()) {
-            *p = v.toBoolean();
-            return true;
-        }
-        return false;
-
-      case JSVAL_TYPE_INT32:
-        if (v.isInt32()) {
-            *reinterpret_cast<int32_t*>(p) = v.toInt32();
-            return true;
-        }
-        return false;
-
-      case JSVAL_TYPE_DOUBLE:
-        if (v.isNumber()) {
-            *reinterpret_cast<double*>(p) = v.toNumber();
-            return true;
-        }
-        return false;
-
-      case JSVAL_TYPE_STRING:
-        if (v.isString()) {
-            MOZ_ASSERT(!IsInsideNursery(v.toString()));
-            JSString** np = reinterpret_cast<JSString**>(p);
-            if (preBarrier)
-                JSString::writeBarrierPre(*np);
-            *np = v.toString();
-            return true;
-        }
-        return false;
-
-      case JSVAL_TYPE_OBJECT:
-        if (v.isObjectOrNull()) {
-            JSObject** np = reinterpret_cast<JSObject**>(p);
-
-            // Update property types when writing object properties. Types for
-            // other properties were captured when the unboxed layout was
-            // created.
-            AddTypePropertyId(cx, unboxedObject, id, v);
-
-            // As above, trigger post barriers on the whole object.
-            JSObject* obj = v.toObjectOrNull();
-            if (IsInsideNursery(v.toObjectOrNull()) && !IsInsideNursery(unboxedObject)) {
-                JSRuntime* rt = unboxedObject->runtimeFromMainThread();
-                rt->gc.storeBuffer.putWholeCell(unboxedObject);
-            }
-
-            if (preBarrier)
-                JSObject::writeBarrierPre(*np);
-            *np = obj;
-            return true;
-        }
-        return false;
-
-      default:
-        MOZ_CRASH("Invalid type for unboxed value");
-    }
-}
-
-/////////////////////////////////////////////////////////////////////
-// UnboxedPlainObject
-/////////////////////////////////////////////////////////////////////
-
-inline const UnboxedLayout&
-UnboxedPlainObject::layout() const
-{
-    return group()->unboxedLayout();
-}
-
-} // namespace js
-
-#endif // vm_UnboxedObject_inl_h
diff --git a/js/src/vm/UnboxedObject.cpp b/js/src/vm/UnboxedObject.cpp
deleted file mode 100644
index a96fb58a8..000000000
--- a/js/src/vm/UnboxedObject.cpp
+++ /dev/null
@@ -1,759 +0,0 @@
-/* -*- 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/. */
-
-#include "vm/UnboxedObject-inl.h"
-
-#include "jit/BaselineIC.h"
-#include "jit/ExecutableAllocator.h"
-#include "jit/JitCommon.h"
-#include "jit/Linker.h"
-
-#include "jsobjinlines.h"
-
-#include "gc/Nursery-inl.h"
-#include "jit/MacroAssembler-inl.h"
-#include "vm/Shape-inl.h"
-
-using mozilla::ArrayLength;
-using mozilla::DebugOnly;
-using mozilla::PodCopy;
-
-using namespace js;
-
-/////////////////////////////////////////////////////////////////////
-// UnboxedLayout
-/////////////////////////////////////////////////////////////////////
-
-void
-UnboxedLayout::trace(JSTracer* trc)
-{
-    for (size_t i = 0; i < properties_.length(); i++)
-        TraceManuallyBarrieredEdge(trc, &properties_[i].name, "unboxed_layout_name");
-
-    if (newScript())
-        newScript()->trace(trc);
-
-    TraceNullableEdge(trc, &nativeGroup_, "unboxed_layout_nativeGroup");
-    TraceNullableEdge(trc, &nativeShape_, "unboxed_layout_nativeShape");
-    TraceNullableEdge(trc, &allocationScript_, "unboxed_layout_allocationScript");
-    TraceNullableEdge(trc, &replacementGroup_, "unboxed_layout_replacementGroup");
-    TraceNullableEdge(trc, &constructorCode_, "unboxed_layout_constructorCode");
-}
-
-size_t
-UnboxedLayout::sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf)
-{
-    return mallocSizeOf(this)
-         + properties_.sizeOfExcludingThis(mallocSizeOf)
-         + (newScript() ? newScript()->sizeOfIncludingThis(mallocSizeOf) : 0)
-         + mallocSizeOf(traceList());
-}
-
-void
-UnboxedLayout::setNewScript(TypeNewScript* newScript, bool writeBarrier /* = true */)
-{
-    if (newScript_ && writeBarrier)
-        TypeNewScript::writeBarrierPre(newScript_);
-    newScript_ = newScript;
-}
-
-// Constructor code returns a 0x1 value to indicate the constructor code should
-// be cleared.
-static const uintptr_t CLEAR_CONSTRUCTOR_CODE_TOKEN = 0x1;
-
-/* static */ bool
-UnboxedLayout::makeConstructorCode(JSContext* cx, HandleObjectGroup group)
-{
-    // *** STUB ***
-    return false;
-}
-
-void
-UnboxedLayout::detachFromCompartment()
-{
-    if (isInList())
-        remove();
-}
-
-/////////////////////////////////////////////////////////////////////
-// UnboxedPlainObject
-/////////////////////////////////////////////////////////////////////
-
-bool
-UnboxedPlainObject::setValue(ExclusiveContext* cx, const UnboxedLayout::Property& property,
-                             const Value& v)
-{
-    uint8_t* p = &data_[property.offset];
-    return SetUnboxedValue(cx, this, NameToId(property.name), p, property.type, v,
-                           /* preBarrier = */ true);
-}
-
-Value
-UnboxedPlainObject::getValue(const UnboxedLayout::Property& property,
-                             bool maybeUninitialized /* = false */)
-{
-    uint8_t* p = &data_[property.offset];
-    return GetUnboxedValue(p, property.type, maybeUninitialized);
-}
-
-void
-UnboxedPlainObject::trace(JSTracer* trc, JSObject* obj)
-{
-    if (obj->as<UnboxedPlainObject>().expando_) {
-        TraceManuallyBarrieredEdge(trc,
-            reinterpret_cast<NativeObject**>(&obj->as<UnboxedPlainObject>().expando_),
-            "unboxed_expando");
-    }
-
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layoutDontCheckGeneration();
-    const int32_t* list = layout.traceList();
-    if (!list)
-        return;
-
-    uint8_t* data = obj->as<UnboxedPlainObject>().data();
-    while (*list != -1) {
-        GCPtrString* heap = reinterpret_cast<GCPtrString*>(data + *list);
-        TraceEdge(trc, heap, "unboxed_string");
-        list++;
-    }
-    list++;
-    while (*list != -1) {
-        GCPtrObject* heap = reinterpret_cast<GCPtrObject*>(data + *list);
-        TraceNullableEdge(trc, heap, "unboxed_object");
-        list++;
-    }
-
-    // Unboxed objects don't have Values to trace.
-    MOZ_ASSERT(*(list + 1) == -1);
-}
-
-/* static */ UnboxedExpandoObject*
-UnboxedPlainObject::ensureExpando(JSContext* cx, Handle<UnboxedPlainObject*> obj)
-{
-    if (obj->expando_)
-        return obj->expando_;
-
-    UnboxedExpandoObject* expando =
-        NewObjectWithGivenProto<UnboxedExpandoObject>(cx, nullptr, gc::AllocKind::OBJECT4);
-    if (!expando)
-        return nullptr;
-
-    // Don't track property types for expando objects. This allows Baseline
-    // and Ion AddSlot ICs to guard on the unboxed group without guarding on
-    // the expando group.
-    MarkObjectGroupUnknownProperties(cx, expando->group());
-
-    // If the expando is tenured then the original object must also be tenured.
-    // Otherwise barriers triggered on the original object for writes to the
-    // expando (as can happen in the JIT) won't see the tenured->nursery edge.
-    // See WholeCellEdges::mark.
-    MOZ_ASSERT_IF(!IsInsideNursery(expando), !IsInsideNursery(obj));
-
-    // As with setValue(), we need to manually trigger post barriers on the
-    // whole object. If we treat the field as a GCPtrObject and later
-    // convert the object to its native representation, we will end up with a
-    // corrupted store buffer entry.
-    if (IsInsideNursery(expando) && !IsInsideNursery(obj))
-        cx->runtime()->gc.storeBuffer.putWholeCell(obj);
-
-    obj->expando_ = expando;
-    return expando;
-}
-
-bool
-UnboxedPlainObject::containsUnboxedOrExpandoProperty(ExclusiveContext* cx, jsid id) const
-{
-    if (layout().lookup(id))
-        return true;
-
-    if (maybeExpando() && maybeExpando()->containsShapeOrElement(cx, id))
-        return true;
-
-    return false;
-}
-
-static bool
-PropagatePropertyTypes(JSContext* cx, jsid id, ObjectGroup* oldGroup, ObjectGroup* newGroup)
-{
-    HeapTypeSet* typeProperty = oldGroup->maybeGetProperty(id);
-    TypeSet::TypeList types;
-    if (!typeProperty->enumerateTypes(&types)) {
-        ReportOutOfMemory(cx);
-        return false;
-    }
-    for (size_t j = 0; j < types.length(); j++)
-        AddTypePropertyId(cx, newGroup, nullptr, id, types[j]);
-    return true;
-}
-
-static PlainObject*
-MakeReplacementTemplateObject(JSContext* cx, HandleObjectGroup group, const UnboxedLayout &layout)
-{
-    PlainObject* obj = NewObjectWithGroup<PlainObject>(cx, group, layout.getAllocKind(),
-                                                       TenuredObject);
-    if (!obj)
-        return nullptr;
-
-    for (size_t i = 0; i < layout.properties().length(); i++) {
-        const UnboxedLayout::Property& property = layout.properties()[i];
-        if (!obj->addDataProperty(cx, NameToId(property.name), i, JSPROP_ENUMERATE))
-            return nullptr;
-        MOZ_ASSERT(obj->slotSpan() == i + 1);
-        MOZ_ASSERT(!obj->inDictionaryMode());
-    }
-
-    return obj;
-}
-
-/* static */ bool
-UnboxedLayout::makeNativeGroup(JSContext* cx, ObjectGroup* group)
-{
-    AutoEnterAnalysis enter(cx);
-
-    UnboxedLayout& layout = group->unboxedLayout();
-    Rooted<TaggedProto> proto(cx, group->proto());
-
-    MOZ_ASSERT(!layout.nativeGroup());
-
-    RootedObjectGroup replacementGroup(cx);
-
-    // Immediately clear any new script on the group. This is done by replacing
-    // the existing new script with one for a replacement default new group.
-    // This is done so that the size of the replacment group's objects is the
-    // same as that for the unboxed group, so that we do not see polymorphic
-    // slot accesses later on for sites that see converted objects from this
-    // group and objects that were allocated using the replacement new group.
-    if (layout.newScript()) {
-        replacementGroup = ObjectGroupCompartment::makeGroup(cx, &PlainObject::class_, proto);
-        if (!replacementGroup)
-            return false;
-
-        PlainObject* templateObject = MakeReplacementTemplateObject(cx, replacementGroup, layout);
-        if (!templateObject)
-            return false;
-
-        TypeNewScript* replacementNewScript =
-            TypeNewScript::makeNativeVersion(cx, layout.newScript(), templateObject);
-        if (!replacementNewScript)
-            return false;
-
-        replacementGroup->setNewScript(replacementNewScript);
-        gc::TraceTypeNewScript(replacementGroup);
-
-        group->clearNewScript(cx, replacementGroup);
-    }
-
-    // Similarly, if this group is keyed to an allocation site, replace its
-    // entry with a new group that has no unboxed layout.
-    if (layout.allocationScript()) {
-        RootedScript script(cx, layout.allocationScript());
-        jsbytecode* pc = layout.allocationPc();
-
-        replacementGroup = ObjectGroupCompartment::makeGroup(cx, &PlainObject::class_, proto);
-        if (!replacementGroup)
-            return false;
-
-        PlainObject* templateObject = &script->getObject(pc)->as<PlainObject>();
-        replacementGroup->addDefiniteProperties(cx, templateObject->lastProperty());
-
-        cx->compartment()->objectGroups.replaceAllocationSiteGroup(script, pc, JSProto_Object,
-                                                                   replacementGroup);
-
-        // Clear any baseline information at this opcode which might use the old group.
-        if (script->hasBaselineScript()) {
-            jit::ICEntry& entry = script->baselineScript()->icEntryFromPCOffset(script->pcToOffset(pc));
-            jit::ICFallbackStub* fallback = entry.fallbackStub();
-            for (jit::ICStubIterator iter = fallback->beginChain(); !iter.atEnd(); iter++)
-                iter.unlink(cx);
-            if (fallback->isNewObject_Fallback())
-                fallback->toNewObject_Fallback()->setTemplateObject(nullptr);
-            else if (fallback->isNewArray_Fallback())
-                fallback->toNewArray_Fallback()->setTemplateGroup(replacementGroup);
-        }
-    }
-
-    size_t nfixed = gc::GetGCKindSlots(layout.getAllocKind());
-
-    RootedShape shape(cx, EmptyShape::getInitialShape(cx, &PlainObject::class_, proto, nfixed, 0));
-    if (!shape)
-        return false;
-
-    // Add shapes for each property, if this is for a plain object.
-    for (size_t i = 0; i < layout.properties().length(); i++) {
-        const UnboxedLayout::Property& property = layout.properties()[i];
-
-        Rooted<StackShape> child(cx, StackShape(shape->base()->unowned(), NameToId(property.name),
-                                                i, JSPROP_ENUMERATE, 0));
-        shape = cx->zone()->propertyTree.getChild(cx, shape, child);
-        if (!shape)
-            return false;
-    }
-
-    ObjectGroup* nativeGroup =
-        ObjectGroupCompartment::makeGroup(cx, &PlainObject::class_, proto,
-                                          group->flags() & OBJECT_FLAG_DYNAMIC_MASK);
-    if (!nativeGroup)
-        return false;
-
-    // No sense propagating if we don't know what we started with.
-    if (!group->unknownProperties()) {
-        // Propagate all property types from the old group to the new group.
-        for (size_t i = 0; i < layout.properties().length(); i++) {
-            const UnboxedLayout::Property& property = layout.properties()[i];
-            jsid id = NameToId(property.name);
-            if (!PropagatePropertyTypes(cx, id, group, nativeGroup))
-                return false;
-
-            // If we are OOM we may not be able to propagate properties.
-            if (nativeGroup->unknownProperties())
-                break;
-
-            HeapTypeSet* nativeProperty = nativeGroup->maybeGetProperty(id);
-            if (nativeProperty && nativeProperty->canSetDefinite(i))
-                nativeProperty->setDefinite(i);
-        }
-    } else {
-        // If we skip, though, the new group had better agree.
-        MOZ_ASSERT(nativeGroup->unknownProperties());
-    }
-
-    layout.nativeGroup_ = nativeGroup;
-    layout.nativeShape_ = shape;
-    layout.replacementGroup_ = replacementGroup;
-
-    nativeGroup->setOriginalUnboxedGroup(group);
-
-    group->markStateChange(cx);
-
-    return true;
-}
-
-/* static */ bool
-UnboxedPlainObject::convertToNative(JSContext* cx, JSObject* obj)
-{
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layout();
-    UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando();
-
-    if (!layout.nativeGroup()) {
-        if (!UnboxedLayout::makeNativeGroup(cx, obj->group()))
-            return false;
-
-        // makeNativeGroup can reentrantly invoke this method.
-        if (obj->is<PlainObject>())
-            return true;
-    }
-
-    AutoValueVector values(cx);
-    for (size_t i = 0; i < layout.properties().length(); i++) {
-        // We might be reading properties off the object which have not been
-        // initialized yet. Make sure any double values we read here are
-        // canonicalized.
-        if (!values.append(obj->as<UnboxedPlainObject>().getValue(layout.properties()[i], true)))
-            return false;
-    }
-
-    // We are eliminating the expando edge with the conversion, so trigger a
-    // pre barrier.
-    JSObject::writeBarrierPre(expando);
-
-    // Additionally trigger a post barrier on the expando itself. Whole cell
-    // store buffer entries can be added on the original unboxed object for
-    // writes to the expando (see WholeCellEdges::trace), so after conversion
-    // we need to make sure the expando itself will still be traced.
-    if (expando && !IsInsideNursery(expando))
-        cx->runtime()->gc.storeBuffer.putWholeCell(expando);
-
-    obj->setGroup(layout.nativeGroup());
-    obj->as<PlainObject>().setLastPropertyMakeNative(cx, layout.nativeShape());
-
-    for (size_t i = 0; i < values.length(); i++)
-        obj->as<PlainObject>().initSlotUnchecked(i, values[i]);
-
-    if (expando) {
-        // Add properties from the expando object to the object, in order.
-        // Suppress GC here, so that callers don't need to worry about this
-        // method collecting. The stuff below can only fail due to OOM, in
-        // which case the object will not have been completely filled back in.
-        gc::AutoSuppressGC suppress(cx);
-
-        Vector<jsid> ids(cx);
-        for (Shape::Range<NoGC> r(expando->lastProperty()); !r.empty(); r.popFront()) {
-            if (!ids.append(r.front().propid()))
-                return false;
-        }
-        for (size_t i = 0; i < expando->getDenseInitializedLength(); i++) {
-            if (!expando->getDenseElement(i).isMagic(JS_ELEMENTS_HOLE)) {
-                if (!ids.append(INT_TO_JSID(i)))
-                    return false;
-            }
-        }
-        ::Reverse(ids.begin(), ids.end());
-
-        RootedPlainObject nobj(cx, &obj->as<PlainObject>());
-        Rooted<UnboxedExpandoObject*> nexpando(cx, expando);
-        RootedId id(cx);
-        Rooted<PropertyDescriptor> desc(cx);
-        for (size_t i = 0; i < ids.length(); i++) {
-            id = ids[i];
-            if (!GetOwnPropertyDescriptor(cx, nexpando, id, &desc))
-                return false;
-            ObjectOpResult result;
-            if (!DefineProperty(cx, nobj, id, desc, result))
-                return false;
-            MOZ_ASSERT(result.ok());
-        }
-    }
-
-    return true;
-}
-
-/* static */
-UnboxedPlainObject*
-UnboxedPlainObject::create(ExclusiveContext* cx, HandleObjectGroup group, NewObjectKind newKind)
-{
-    AutoSetNewObjectMetadata metadata(cx);
-
-    MOZ_ASSERT(group->clasp() == &class_);
-    gc::AllocKind allocKind = group->unboxedLayout().getAllocKind();
-
-    UnboxedPlainObject* res =
-        NewObjectWithGroup<UnboxedPlainObject>(cx, group, allocKind, newKind);
-    if (!res)
-        return nullptr;
-
-    // Overwrite the dummy shape which was written to the object's expando field.
-    res->initExpando();
-
-    // Initialize reference fields of the object. All fields in the object will
-    // be overwritten shortly, but references need to be safe for the GC.
-    const int32_t* list = res->layout().traceList();
-    if (list) {
-        uint8_t* data = res->data();
-        while (*list != -1) {
-            GCPtrString* heap = reinterpret_cast<GCPtrString*>(data + *list);
-            heap->init(cx->names().empty);
-            list++;
-        }
-        list++;
-        while (*list != -1) {
-            GCPtrObject* heap = reinterpret_cast<GCPtrObject*>(data + *list);
-            heap->init(nullptr);
-            list++;
-        }
-        // Unboxed objects don't have Values to initialize.
-        MOZ_ASSERT(*(list + 1) == -1);
-    }
-
-    return res;
-}
-
-/* static */ JSObject*
-UnboxedPlainObject::createWithProperties(ExclusiveContext* cx, HandleObjectGroup group,
-                                         NewObjectKind newKind, IdValuePair* properties)
-{
-    MOZ_ASSERT(newKind == GenericObject || newKind == TenuredObject);
-
-    UnboxedLayout& layout = group->unboxedLayout();
-
-    if (layout.constructorCode()) {
-        MOZ_ASSERT(cx->isJSContext());
-
-        typedef JSObject* (*ConstructorCodeSignature)(IdValuePair*, NewObjectKind);
-        ConstructorCodeSignature function =
-            reinterpret_cast<ConstructorCodeSignature>(layout.constructorCode()->raw());
-
-        JSObject* obj;
-        {
-            JS::AutoSuppressGCAnalysis nogc;
-            obj = reinterpret_cast<JSObject*>(CALL_GENERATED_2(function, properties, newKind));
-        }
-        if (obj > reinterpret_cast<JSObject*>(CLEAR_CONSTRUCTOR_CODE_TOKEN))
-            return obj;
-
-        if (obj == reinterpret_cast<JSObject*>(CLEAR_CONSTRUCTOR_CODE_TOKEN))
-            layout.setConstructorCode(nullptr);
-    }
-
-    UnboxedPlainObject* obj = UnboxedPlainObject::create(cx, group, newKind);
-    if (!obj)
-        return nullptr;
-
-    for (size_t i = 0; i < layout.properties().length(); i++) {
-        if (!obj->setValue(cx, layout.properties()[i], properties[i].value))
-            return NewPlainObjectWithProperties(cx, properties, layout.properties().length(), newKind);
-    }
-
-#ifndef JS_CODEGEN_NONE
-    if (cx->isJSContext() &&
-        !group->unknownProperties() &&
-        !layout.constructorCode() &&
-        cx->asJSContext()->runtime()->jitSupportsFloatingPoint &&
-        jit::CanLikelyAllocateMoreExecutableMemory())
-    {
-        if (!UnboxedLayout::makeConstructorCode(cx->asJSContext(), group))
-            return nullptr;
-    }
-#endif
-
-    return obj;
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_lookupProperty(JSContext* cx, HandleObject obj,
-                                       HandleId id, MutableHandleObject objp,
-                                       MutableHandleShape propp)
-{
-    if (obj->as<UnboxedPlainObject>().containsUnboxedOrExpandoProperty(cx, id)) {
-        MarkNonNativePropertyFound<CanGC>(propp);
-        objp.set(obj);
-        return true;
-    }
-
-    RootedObject proto(cx, obj->staticPrototype());
-    if (!proto) {
-        objp.set(nullptr);
-        propp.set(nullptr);
-        return true;
-    }
-
-    return LookupProperty(cx, proto, id, objp, propp);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_defineProperty(JSContext* cx, HandleObject obj, HandleId id,
-                                       Handle<PropertyDescriptor> desc,
-                                       ObjectOpResult& result)
-{
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layout();
-
-    if (const UnboxedLayout::Property* property = layout.lookup(id)) {
-        if (!desc.getter() && !desc.setter() && desc.attributes() == JSPROP_ENUMERATE) {
-            // This define is equivalent to setting an existing property.
-            if (obj->as<UnboxedPlainObject>().setValue(cx, *property, desc.value()))
-                return result.succeed();
-        }
-
-        // Trying to incompatibly redefine an existing property requires the
-        // object to be converted to a native object.
-        if (!convertToNative(cx, obj))
-            return false;
-
-        return DefineProperty(cx, obj, id, desc, result);
-    }
-
-    // Define the property on the expando object.
-    Rooted<UnboxedExpandoObject*> expando(cx, ensureExpando(cx, obj.as<UnboxedPlainObject>()));
-    if (!expando)
-        return false;
-
-    // Update property types on the unboxed object as well.
-    AddTypePropertyId(cx, obj, id, desc.value());
-
-    return DefineProperty(cx, expando, id, desc, result);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_hasProperty(JSContext* cx, HandleObject obj, HandleId id, bool* foundp)
-{
-    if (obj->as<UnboxedPlainObject>().containsUnboxedOrExpandoProperty(cx, id)) {
-        *foundp = true;
-        return true;
-    }
-
-    RootedObject proto(cx, obj->staticPrototype());
-    if (!proto) {
-        *foundp = false;
-        return true;
-    }
-
-    return HasProperty(cx, proto, id, foundp);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_getProperty(JSContext* cx, HandleObject obj, HandleValue receiver,
-                                    HandleId id, MutableHandleValue vp)
-{
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layout();
-
-    if (const UnboxedLayout::Property* property = layout.lookup(id)) {
-        vp.set(obj->as<UnboxedPlainObject>().getValue(*property));
-        return true;
-    }
-
-    if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando()) {
-        if (expando->containsShapeOrElement(cx, id)) {
-            RootedObject nexpando(cx, expando);
-            return GetProperty(cx, nexpando, receiver, id, vp);
-        }
-    }
-
-    RootedObject proto(cx, obj->staticPrototype());
-    if (!proto) {
-        vp.setUndefined();
-        return true;
-    }
-
-    return GetProperty(cx, proto, receiver, id, vp);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_setProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
-                                    HandleValue receiver, ObjectOpResult& result)
-{
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layout();
-
-    if (const UnboxedLayout::Property* property = layout.lookup(id)) {
-        if (receiver.isObject() && obj == &receiver.toObject()) {
-            if (obj->as<UnboxedPlainObject>().setValue(cx, *property, v))
-                return result.succeed();
-
-            if (!convertToNative(cx, obj))
-                return false;
-            return SetProperty(cx, obj, id, v, receiver, result);
-        }
-
-        return SetPropertyByDefining(cx, id, v, receiver, result);
-    }
-
-    if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando()) {
-        if (expando->containsShapeOrElement(cx, id)) {
-            // Update property types on the unboxed object as well.
-            AddTypePropertyId(cx, obj, id, v);
-
-            RootedObject nexpando(cx, expando);
-            return SetProperty(cx, nexpando, id, v, receiver, result);
-        }
-    }
-
-    return SetPropertyOnProto(cx, obj, id, v, receiver, result);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_getOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
-                                                 MutableHandle<PropertyDescriptor> desc)
-{
-    const UnboxedLayout& layout = obj->as<UnboxedPlainObject>().layout();
-
-    if (const UnboxedLayout::Property* property = layout.lookup(id)) {
-        desc.value().set(obj->as<UnboxedPlainObject>().getValue(*property));
-        desc.setAttributes(JSPROP_ENUMERATE);
-        desc.object().set(obj);
-        return true;
-    }
-
-    if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando()) {
-        if (expando->containsShapeOrElement(cx, id)) {
-            RootedObject nexpando(cx, expando);
-            if (!GetOwnPropertyDescriptor(cx, nexpando, id, desc))
-                return false;
-            if (desc.object() == nexpando)
-                desc.object().set(obj);
-            return true;
-        }
-    }
-
-    desc.object().set(nullptr);
-    return true;
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_deleteProperty(JSContext* cx, HandleObject obj, HandleId id,
-                                       ObjectOpResult& result)
-{
-    if (!convertToNative(cx, obj))
-        return false;
-    return DeleteProperty(cx, obj, id, result);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_watch(JSContext* cx, HandleObject obj, HandleId id, HandleObject callable)
-{
-    if (!convertToNative(cx, obj))
-        return false;
-    return WatchProperty(cx, obj, id, callable);
-}
-
-/* static */ bool
-UnboxedPlainObject::obj_enumerate(JSContext* cx, HandleObject obj, AutoIdVector& properties,
-                                  bool enumerableOnly)
-{
-    // Ignore expando properties here, they are special-cased by the property
-    // enumeration code.
-
-    const UnboxedLayout::PropertyVector& unboxed = obj->as<UnboxedPlainObject>().layout().properties();
-    for (size_t i = 0; i < unboxed.length(); i++) {
-        if (!properties.append(NameToId(unboxed[i].name)))
-            return false;
-    }
-
-    return true;
-}
-
-const Class UnboxedExpandoObject::class_ = {
-    "UnboxedExpandoObject",
-    0
-};
-
-static const ClassOps UnboxedPlainObjectClassOps = {
-    nullptr,        /* addProperty */
-    nullptr,        /* delProperty */
-    nullptr,        /* getProperty */
-    nullptr,        /* setProperty */
-    nullptr,        /* enumerate   */
-    nullptr,        /* resolve     */
-    nullptr,        /* mayResolve  */
-    nullptr,        /* finalize    */
-    nullptr,        /* call        */
-    nullptr,        /* hasInstance */
-    nullptr,        /* construct   */
-    UnboxedPlainObject::trace,
-};
-
-static const ObjectOps UnboxedPlainObjectObjectOps = {
-    UnboxedPlainObject::obj_lookupProperty,
-    UnboxedPlainObject::obj_defineProperty,
-    UnboxedPlainObject::obj_hasProperty,
-    UnboxedPlainObject::obj_getProperty,
-    UnboxedPlainObject::obj_setProperty,
-    UnboxedPlainObject::obj_getOwnPropertyDescriptor,
-    UnboxedPlainObject::obj_deleteProperty,
-    UnboxedPlainObject::obj_watch,
-    nullptr,   /* No unwatch needed, as watch() converts the object to native */
-    nullptr,   /* getElements */
-    UnboxedPlainObject::obj_enumerate,
-    nullptr    /* funToString */
-};
-
-const Class UnboxedPlainObject::class_ = {
-    js_Object_str,
-    Class::NON_NATIVE |
-    JSCLASS_HAS_CACHED_PROTO(JSProto_Object) |
-    JSCLASS_DELAY_METADATA_BUILDER,
-    &UnboxedPlainObjectClassOps,
-    JS_NULL_CLASS_SPEC,
-    JS_NULL_CLASS_EXT,
-    &UnboxedPlainObjectObjectOps
-};
-
-/////////////////////////////////////////////////////////////////////
-// API
-/////////////////////////////////////////////////////////////////////
-
-static inline Value
-NextValue(Handle<GCVector<Value>> values, size_t* valueCursor)
-{
-    return values[(*valueCursor)++];
-}
-
-void
-UnboxedPlainObject::fillAfterConvert(ExclusiveContext* cx,
-                                     Handle<GCVector<Value>> values, size_t* valueCursor)
-{
-    initExpando();
-    memset(data(), 0, layout().size());
-    for (size_t i = 0; i < layout().properties().length(); i++)
-        JS_ALWAYS_TRUE(setValue(cx, layout().properties()[i], NextValue(values, valueCursor)));
-}
diff --git a/js/src/vm/UnboxedObject.h b/js/src/vm/UnboxedObject.h
deleted file mode 100644
index ba66434bc..000000000
--- a/js/src/vm/UnboxedObject.h
+++ /dev/null
@@ -1,319 +0,0 @@
-/* -*- 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_UnboxedObject_h
-#define vm_UnboxedObject_h
-
-#include "jsgc.h"
-#include "jsobj.h"
-
-#include "vm/Runtime.h"
-#include "vm/TypeInference.h"
-
-namespace js {
-
-// Memory required for an unboxed value of a given type. Returns zero for types
-// which can't be used for unboxed objects.
-static inline size_t
-UnboxedTypeSize(JSValueType type)
-{
-    switch (type) {
-      case JSVAL_TYPE_BOOLEAN: return 1;
-      case JSVAL_TYPE_INT32:   return 4;
-      case JSVAL_TYPE_DOUBLE:  return 8;
-      case JSVAL_TYPE_STRING:  return sizeof(void*);
-      case JSVAL_TYPE_OBJECT:  return sizeof(void*);
-      default:                 return 0;
-    }
-}
-
-static inline bool
-UnboxedTypeNeedsPreBarrier(JSValueType type)
-{
-    return type == JSVAL_TYPE_STRING || type == JSVAL_TYPE_OBJECT;
-}
-
-static inline bool
-UnboxedTypeNeedsPostBarrier(JSValueType type)
-{
-    return type == JSVAL_TYPE_OBJECT;
-}
-
-// Class tracking information specific to unboxed objects.
-class UnboxedLayout : public mozilla::LinkedListElement<UnboxedLayout>
-{
-  public:
-    struct Property {
-        PropertyName* name;
-        uint32_t offset;
-        JSValueType type;
-
-        Property()
-          : name(nullptr), offset(UINT32_MAX), type(JSVAL_TYPE_MAGIC)
-        {}
-    };
-
-    typedef Vector<Property, 0, SystemAllocPolicy> PropertyVector;
-
-  private:
-    // If objects in this group have ever been converted to native objects,
-    // these store the corresponding native group and initial shape for such
-    // objects. Type information for this object is reflected in nativeGroup.
-    GCPtrObjectGroup nativeGroup_;
-    GCPtrShape nativeShape_;
-
-    // Any script/pc which the associated group is created for.
-    GCPtrScript allocationScript_;
-    jsbytecode* allocationPc_;
-
-    // If nativeGroup is set and this object originally had a TypeNewScript or
-    // was keyed to an allocation site, this points to the group which replaced
-    // this one. This link is only needed to keep the replacement group from
-    // being GC'ed. If it were GC'ed and a new one regenerated later, that new
-    // group might have a different allocation kind from this group.
-    GCPtrObjectGroup replacementGroup_;
-
-    // The following members are only used for unboxed plain objects.
-
-    // All properties on objects with this layout, in enumeration order.
-    PropertyVector properties_;
-
-    // Byte size of the data for objects with this layout.
-    size_t size_;
-
-    // Any 'new' script information associated with this layout.
-    TypeNewScript* newScript_;
-
-    // List for use in tracing objects with this layout. This has the same
-    // structure as the trace list on a TypeDescr.
-    int32_t* traceList_;
-
-    // If this layout has been used to construct script or JSON constant
-    // objects, this code might be filled in to more quickly fill in objects
-    // from an array of values.
-    GCPtrJitCode constructorCode_;
-
-  public:
-    UnboxedLayout()
-      : nativeGroup_(nullptr), nativeShape_(nullptr),
-        allocationScript_(nullptr), allocationPc_(nullptr), replacementGroup_(nullptr),
-        size_(0), newScript_(nullptr), traceList_(nullptr), constructorCode_(nullptr)
-    {}
-
-    bool initProperties(const PropertyVector& properties, size_t size) {
-        size_ = size;
-        return properties_.appendAll(properties);
-    }
-
-    ~UnboxedLayout() {
-        if (newScript_)
-            newScript_->clear();
-        js_delete(newScript_);
-        js_free(traceList_);
-
-        nativeGroup_.init(nullptr);
-        nativeShape_.init(nullptr);
-        replacementGroup_.init(nullptr);
-        constructorCode_.init(nullptr);
-    }
-
-    void detachFromCompartment();
-
-    const PropertyVector& properties() const {
-        return properties_;
-    }
-
-    TypeNewScript* newScript() const {
-        return newScript_;
-    }
-
-    void setNewScript(TypeNewScript* newScript, bool writeBarrier = true);
-
-    JSScript* allocationScript() const {
-        return allocationScript_;
-    }
-
-    jsbytecode* allocationPc() const {
-        return allocationPc_;
-    }
-
-    void setAllocationSite(JSScript* script, jsbytecode* pc) {
-        allocationScript_ = script;
-        allocationPc_ = pc;
-    }
-
-    const int32_t* traceList() const {
-        return traceList_;
-    }
-
-    void setTraceList(int32_t* traceList) {
-        traceList_ = traceList;
-    }
-
-    const Property* lookup(JSAtom* atom) const {
-        for (size_t i = 0; i < properties_.length(); i++) {
-            if (properties_[i].name == atom)
-                return &properties_[i];
-        }
-        return nullptr;
-    }
-
-    const Property* lookup(jsid id) const {
-        if (JSID_IS_STRING(id))
-            return lookup(JSID_TO_ATOM(id));
-        return nullptr;
-    }
-
-    size_t size() const {
-        return size_;
-    }
-
-    ObjectGroup* nativeGroup() const {
-        return nativeGroup_;
-    }
-
-    Shape* nativeShape() const {
-        return nativeShape_;
-    }
-
-    jit::JitCode* constructorCode() const {
-        return constructorCode_;
-    }
-
-    void setConstructorCode(jit::JitCode* code) {
-        constructorCode_ = code;
-    }
-
-    inline gc::AllocKind getAllocKind() const;
-
-    void trace(JSTracer* trc);
-
-    size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf);
-
-    static bool makeNativeGroup(JSContext* cx, ObjectGroup* group);
-    static bool makeConstructorCode(JSContext* cx, HandleObjectGroup group);
-};
-
-// Class for expando objects holding extra properties given to an unboxed plain
-// object. These objects behave identically to normal native plain objects, and
-// have a separate Class to distinguish them for memory usage reporting.
-class UnboxedExpandoObject : public NativeObject
-{
-  public:
-    static const Class class_;
-};
-
-// Class for a plain object using an unboxed representation. The physical
-// layout of these objects is identical to that of an InlineTypedObject, though
-// these objects use an UnboxedLayout instead of a TypeDescr to keep track of
-// how their properties are stored.
-class UnboxedPlainObject : public JSObject
-{
-    // Optional object which stores extra properties on this object. This is
-    // not automatically barriered to avoid problems if the object is converted
-    // to a native. See ensureExpando().
-    UnboxedExpandoObject* expando_;
-
-    // Start of the inline data, which immediately follows the group and extra properties.
-    uint8_t data_[1];
-
-  public:
-    static const Class class_;
-
-    static bool obj_lookupProperty(JSContext* cx, HandleObject obj,
-                                   HandleId id, MutableHandleObject objp,
-                                   MutableHandleShape propp);
-
-    static bool obj_defineProperty(JSContext* cx, HandleObject obj, HandleId id,
-                                   Handle<PropertyDescriptor> desc,
-                                   ObjectOpResult& result);
-
-    static bool obj_hasProperty(JSContext* cx, HandleObject obj, HandleId id, bool* foundp);
-
-    static bool obj_getProperty(JSContext* cx, HandleObject obj, HandleValue receiver,
-                                HandleId id, MutableHandleValue vp);
-
-    static bool obj_setProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
-                                HandleValue receiver, ObjectOpResult& result);
-
-    static bool obj_getOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
-                                             MutableHandle<PropertyDescriptor> desc);
-
-    static bool obj_deleteProperty(JSContext* cx, HandleObject obj, HandleId id,
-                                   ObjectOpResult& result);
-
-    static bool obj_enumerate(JSContext* cx, HandleObject obj, AutoIdVector& properties,
-                              bool enumerableOnly);
-    static bool obj_watch(JSContext* cx, HandleObject obj, HandleId id, HandleObject callable);
-
-    inline const UnboxedLayout& layout() const;
-
-    const UnboxedLayout& layoutDontCheckGeneration() const {
-        return group()->unboxedLayoutDontCheckGeneration();
-    }
-
-    uint8_t* data() {
-        return &data_[0];
-    }
-
-    UnboxedExpandoObject* maybeExpando() const {
-        return expando_;
-    }
-
-    void initExpando() {
-        expando_ = nullptr;
-    }
-
-    // For use during GC.
-    JSObject** addressOfExpando() {
-        return reinterpret_cast<JSObject**>(&expando_);
-    }
-
-    bool containsUnboxedOrExpandoProperty(ExclusiveContext* cx, jsid id) const;
-
-    static UnboxedExpandoObject* ensureExpando(JSContext* cx, Handle<UnboxedPlainObject*> obj);
-
-    bool setValue(ExclusiveContext* cx, const UnboxedLayout::Property& property, const Value& v);
-    Value getValue(const UnboxedLayout::Property& property, bool maybeUninitialized = false);
-
-    static bool convertToNative(JSContext* cx, JSObject* obj);
-    static UnboxedPlainObject* create(ExclusiveContext* cx, HandleObjectGroup group,
-                                      NewObjectKind newKind);
-    static JSObject* createWithProperties(ExclusiveContext* cx, HandleObjectGroup group,
-                                          NewObjectKind newKind, IdValuePair* properties);
-
-    void fillAfterConvert(ExclusiveContext* cx,
-                          Handle<GCVector<Value>> values, size_t* valueCursor);
-
-    static void trace(JSTracer* trc, JSObject* object);
-
-    static size_t offsetOfExpando() {
-        return offsetof(UnboxedPlainObject, expando_);
-    }
-
-    static size_t offsetOfData() {
-        return offsetof(UnboxedPlainObject, data_[0]);
-    }
-};
-
-inline gc::AllocKind
-UnboxedLayout::getAllocKind() const
-{
-    MOZ_ASSERT(size());
-    return gc::GetGCObjectKindForBytes(UnboxedPlainObject::offsetOfData() + size());
-}
-
-} // namespace js
-
-namespace JS {
-
-template <>
-struct DeletePolicy<js::UnboxedLayout> : public js::GCManagedDeletePolicy<js::UnboxedLayout>
-{};
-
-} /* namespace JS */
-
-#endif /* vm_UnboxedObject_h */