Inline combined methods for NativeObject and UnboxedArrayObject accesses.

9 files changed, 115 insertions, 224 deletions

diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index 1d230e083..28e263ac7 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -2373,8 +2373,8 @@ CanOptimizeDenseOrUnboxedArraySetElem(JSObject* obj, uint32_t index,
                                       Shape* oldShape, uint32_t oldCapacity, uint32_t oldInitLength,
                                       bool* isAddingCaseOut, size_t* protoDepthOut)
 {
-    uint32_t initLength = GetAnyBoxedOrUnboxedInitializedLength(obj);
-    uint32_t capacity = GetAnyBoxedOrUnboxedCapacity(obj);
+    uint32_t initLength = obj->as<NativeObject>().getDenseInitializedLength();
+    uint32_t capacity = obj->as<NativeObject>().getDenseCapacity();
 
     *isAddingCaseOut = false;
     *protoDepthOut = 0;
@@ -2464,8 +2464,8 @@ DoSetElemFallback(JSContext* cx, BaselineFrame* frame, ICSetElem_Fallback* stub_
     uint32_t oldCapacity = 0;
     uint32_t oldInitLength = 0;
     if (index.isInt32() && index.toInt32() >= 0) {
-        oldCapacity = GetAnyBoxedOrUnboxedCapacity(obj);
-        oldInitLength = GetAnyBoxedOrUnboxedInitializedLength(obj);
+        oldCapacity = obj->as<NativeObject>().getDenseCapacity();
+        oldInitLength = obj->as<NativeObject>().getDenseInitializedLength();
     }
 
     if (op == JSOP_INITELEM || op == JSOP_INITHIDDENELEM) {
@@ -5762,14 +5762,14 @@ TryAttachCallStub(JSContext* cx, ICCall_Fallback* stub, HandleScript script, jsb
 }
 
 static bool
-CopyArray(JSContext* cx, HandleObject obj, MutableHandleValue result)
+CopyArray(JSContext* cx, HandleArrayObject arr, MutableHandleValue result)
 {
-    uint32_t length = GetAnyBoxedOrUnboxedArrayLength(obj);
-    JSObject* nobj = NewFullyAllocatedArrayTryReuseGroup(cx, obj, length, TenuredObject);
+    uint32_t length = arr->length();
+    JSObject* nobj = NewFullyAllocatedArrayTryReuseGroup(cx, arr, length, TenuredObject);
     if (!nobj)
         return false;
     EnsureArrayGroupAnalyzed(cx, nobj);
-    CopyBoxedOrUnboxedDenseElements(cx, nobj, obj, 0, 0, length);
+    CopyBoxedOrUnboxedDenseElements(cx, nobj, arr, 0, 0, length);
 
     result.setObject(*nobj);
     return true;
@@ -5801,26 +5801,22 @@ TryAttachStringSplit(JSContext* cx, ICCall_Fallback* stub, HandleScript script,
     RootedValue arr(cx);
 
     // Copy the array before storing in stub.
-    if (!CopyArray(cx, obj, &arr))
+    if (!CopyArray(cx, obj.as<ArrayObject>(), &arr))
         return false;
 
     // Atomize all elements of the array.
-    RootedObject arrObj(cx, &arr.toObject());
-    uint32_t initLength = GetAnyBoxedOrUnboxedArrayLength(arrObj);
+    RootedArrayObject arrObj(cx, &arr.toObject().as<ArrayObject>());
+    uint32_t initLength = arrObj->length();
     for (uint32_t i = 0; i < initLength; i++) {
-        JSAtom* str = js::AtomizeString(cx, GetAnyBoxedOrUnboxedDenseElement(arrObj, i).toString());
+        JSAtom* str = js::AtomizeString(cx, arrObj->getDenseElement(i).toString());
         if (!str)
             return false;
 
-        if (!SetAnyBoxedOrUnboxedDenseElement(cx, arrObj, i, StringValue(str))) {
-            // The value could not be stored to an unboxed dense element.
-            return true;
-        }
+        arrObj->setDenseElementWithType(cx, i, StringValue(str));
     }
 
     ICCall_StringSplit::Compiler compiler(cx, stub->fallbackMonitorStub()->firstMonitorStub(),
-                                          script->pcToOffset(pc), str, sep,
-                                          arr);
+                                          script->pcToOffset(pc), str, sep, arrObj);
     ICStub* newStub = compiler.getStub(compiler.getStubSpace(script));
     if (!newStub)
         return false;
@@ -6705,7 +6701,7 @@ ICCallScriptedCompiler::generateStubCode(MacroAssembler& masm)
     return true;
 }
 
-typedef bool (*CopyArrayFn)(JSContext*, HandleObject, MutableHandleValue);
+typedef bool (*CopyArrayFn)(JSContext*, HandleArrayObject, MutableHandleValue);
 static const VMFunction CopyArrayInfo = FunctionInfo<CopyArrayFn>(CopyArray, "CopyArray");
 
 bool
diff --git a/js/src/jit/BaselineIC.h b/js/src/jit/BaselineIC.h
index afbea3b69..901fca9cc 100644
--- a/js/src/jit/BaselineIC.h
+++ b/js/src/jit/BaselineIC.h
@@ -2818,10 +2818,10 @@ class ICCall_StringSplit : public ICMonitoredStub
     uint32_t pcOffset_;
     GCPtrString expectedStr_;
     GCPtrString expectedSep_;
-    GCPtrObject templateObject_;
+    GCPtrArrayObject templateObject_;
 
     ICCall_StringSplit(JitCode* stubCode, ICStub* firstMonitorStub, uint32_t pcOffset, JSString* str,
-                       JSString* sep, JSObject* templateObject)
+                       JSString* sep, ArrayObject* templateObject)
       : ICMonitoredStub(ICStub::Call_StringSplit, stubCode, firstMonitorStub),
         pcOffset_(pcOffset), expectedStr_(str), expectedSep_(sep),
         templateObject_(templateObject)
@@ -2848,7 +2848,7 @@ class ICCall_StringSplit : public ICMonitoredStub
         return expectedSep_;
     }
 
-    GCPtrObject& templateObject() {
+    GCPtrArrayObject& templateObject() {
         return templateObject_;
     }
 
@@ -2858,7 +2858,7 @@ class ICCall_StringSplit : public ICMonitoredStub
         uint32_t pcOffset_;
         RootedString expectedStr_;
         RootedString expectedSep_;
-        RootedObject templateObject_;
+        RootedArrayObject templateObject_;
 
         MOZ_MUST_USE bool generateStubCode(MacroAssembler& masm);
 
@@ -2869,13 +2869,13 @@ class ICCall_StringSplit : public ICMonitoredStub
 
       public:
         Compiler(JSContext* cx, ICStub* firstMonitorStub, uint32_t pcOffset, HandleString str,
-                 HandleString sep, HandleValue templateObject)
+                 HandleString sep, HandleArrayObject templateObject)
           : ICCallStubCompiler(cx, ICStub::Call_StringSplit),
             firstMonitorStub_(firstMonitorStub),
             pcOffset_(pcOffset),
             expectedStr_(cx, str),
             expectedSep_(cx, sep),
-            templateObject_(cx, &templateObject.toObject())
+            templateObject_(cx, templateObject)
         { }
 
         ICStub* getStub(ICStubSpace* space) {
diff --git a/js/src/jit/BaselineInspector.cpp b/js/src/jit/BaselineInspector.cpp
index 9c7b88fb2..bcb527516 100644
--- a/js/src/jit/BaselineInspector.cpp
+++ b/js/src/jit/BaselineInspector.cpp
@@ -580,7 +580,7 @@ BaselineInspector::getTemplateObjectForNative(jsbytecode* pc, Native native)
 
 bool
 BaselineInspector::isOptimizableCallStringSplit(jsbytecode* pc, JSString** strOut, JSString** sepOut,
-                                                JSObject** objOut)
+                                                ArrayObject** objOut)
 {
     if (!hasBaselineScript())
         return false;
diff --git a/js/src/jit/BaselineInspector.h b/js/src/jit/BaselineInspector.h
index 4a1791798..1ed4b5547 100644
--- a/js/src/jit/BaselineInspector.h
+++ b/js/src/jit/BaselineInspector.h
@@ -113,7 +113,7 @@ class BaselineInspector
     bool hasSeenNonStringIterMore(jsbytecode* pc);
 
     MOZ_MUST_USE bool isOptimizableCallStringSplit(jsbytecode* pc, JSString** strOut,
-                                                   JSString** sepOut, JSObject** objOut);
+                                                   JSString** sepOut, ArrayObject** objOut);
     JSObject* getTemplateObject(jsbytecode* pc);
     JSObject* getTemplateObjectForNative(jsbytecode* pc, Native native);
     JSObject* getTemplateObjectForClassHook(jsbytecode* pc, const Class* clasp);
diff --git a/js/src/jit/MCallOptimize.cpp b/js/src/jit/MCallOptimize.cpp
index 748a70973..0d5779cee 100644
--- a/js/src/jit/MCallOptimize.cpp
+++ b/js/src/jit/MCallOptimize.cpp
@@ -522,7 +522,7 @@ IonBuilder::inlineArray(CallInfo& callInfo)
         // Make sure initLength matches the template object's length. This is
         // not guaranteed to be the case, for instance if we're inlining the
         // MConstant may come from an outer script.
-        if (initLength != GetAnyBoxedOrUnboxedArrayLength(templateObject))
+        if (initLength != templateObject->as<ArrayObject>().length())
             return InliningStatus_NotInlined;
 
         // Don't inline large allocations.
@@ -1396,7 +1396,7 @@ IonBuilder::inlineConstantStringSplitString(CallInfo& callInfo)
     // Check if exist a template object in stub.
     JSString* stringStr = nullptr;
     JSString* stringSep = nullptr;
-    JSObject* templateObject = nullptr;
+    ArrayObject* templateObject = nullptr;
     if (!inspector->isOptimizableCallStringSplit(pc, &stringStr, &stringSep, &templateObject))
         return InliningStatus_NotInlined;
 
@@ -1422,13 +1422,13 @@ IonBuilder::inlineConstantStringSplitString(CallInfo& callInfo)
     if (!key.maybeTypes()->hasType(TypeSet::StringType()))
         return InliningStatus_NotInlined;
 
-    uint32_t initLength = GetAnyBoxedOrUnboxedArrayLength(templateObject);
-    if (GetAnyBoxedOrUnboxedInitializedLength(templateObject) != initLength)
+    uint32_t initLength = templateObject->length();
+    if (templateObject->getDenseInitializedLength() != initLength)
         return InliningStatus_NotInlined;
 
     Vector<MConstant*, 0, SystemAllocPolicy> arrayValues;
     for (uint32_t i = 0; i < initLength; i++) {
-        Value str = GetAnyBoxedOrUnboxedDenseElement(templateObject, i);
+        Value str = templateObject->getDenseElement(i);
         MOZ_ASSERT(str.toString()->isAtom());
         MConstant* value = MConstant::New(alloc().fallible(), str, constraints());
         if (!value)
diff --git a/js/src/jit/VMFunctions.cpp b/js/src/jit/VMFunctions.cpp
index 0717bb86d..7b1e1cad6 100644
--- a/js/src/jit/VMFunctions.cpp
+++ b/js/src/jit/VMFunctions.cpp
@@ -339,7 +339,7 @@ ArrayPopDense(JSContext* cx, HandleObject obj, MutableHandleValue rval)
 bool
 ArrayPushDense(JSContext* cx, HandleObject obj, HandleValue v, uint32_t* length)
 {
-    *length = GetAnyBoxedOrUnboxedArrayLength(obj);
+    *length = obj->as<ArrayObject>().length();
     DenseElementResult result =
         SetOrExtendBoxedOrUnboxedDenseElements(cx, obj, *length, v.address(), 1,
                                                ShouldUpdateTypes::DontUpdate);
diff --git a/js/src/jsarray.cpp b/js/src/jsarray.cpp
index a8bd3f028..da692c1b5 100644
--- a/js/src/jsarray.cpp
+++ b/js/src/jsarray.cpp
@@ -248,18 +248,20 @@ static bool
 GetElement(JSContext* cx, HandleObject obj, HandleObject receiver,
            uint32_t index, bool* hole, MutableHandleValue vp)
 {
-    AssertGreaterThanZero(index);
-    if (index < GetAnyBoxedOrUnboxedInitializedLength(obj)) {
-        vp.set(GetAnyBoxedOrUnboxedDenseElement(obj, uint32_t(index)));
-        if (!vp.isMagic(JS_ELEMENTS_HOLE)) {
-            *hole = false;
-            return true;
+    if (obj->isNative()) {
+        NativeObject* nobj = &obj->as<NativeObject>();
+        if (index < nobj->getDenseInitializedLength()) {
+            vp.set(nobj->getDenseElement(size_t(index)));
+            if (!vp.isMagic(JS_ELEMENTS_HOLE)) {
+                *hole = false;
+                return true;
+            }
         }
-    }
-    if (obj->is<ArgumentsObject>()) {
-        if (obj->as<ArgumentsObject>().maybeGetElement(uint32_t(index), vp)) {
-            *hole = false;
-            return true;
+        if (nobj->is<ArgumentsObject>() && index <= UINT32_MAX) {
+            if (nobj->as<ArgumentsObject>().maybeGetElement(uint32_t(index), vp)) {
+                *hole = false;
+                return true;
+            }
         }
     }
 
@@ -337,11 +339,11 @@ GetBoxedOrUnboxedDenseElements(JSObject* aobj, uint32_t length, Value* vp)
 {
     MOZ_ASSERT(!ObjectMayHaveExtraIndexedProperties(aobj));
 
-    if (length > GetBoxedOrUnboxedInitializedLength(aobj))
+    if (length > aobj->as<NativeObject>().getDenseInitializedLength())
         return DenseElementResult::Incomplete;
 
     for (size_t i = 0; i < length; i++) {
-        vp[i] = GetBoxedOrUnboxedDenseElement(aobj, i);
+        vp[i] = aobj->as<NativeObject>().getDenseElement(i);
 
         // No other indexed properties so hole => undefined.
         if (vp[i].isMagic(JS_ELEMENTS_HOLE))
@@ -849,7 +851,7 @@ js::ObjectMayHaveExtraIndexedProperties(JSObject* obj)
 
         if (ObjectMayHaveExtraIndexedOwnProperties(obj))
             return true;
-        if (GetAnyBoxedOrUnboxedInitializedLength(obj) != 0)
+        if (obj->as<NativeObject>().getDenseInitializedLength() != 0)
             return true;
     } while (true);
 }
@@ -1068,12 +1070,13 @@ ArrayJoinDenseKernel(JSContext* cx, SeparatorOp sepOp, HandleObject obj, uint32_
     // length > initLength we rely on the second loop to add the
     // other elements.
     MOZ_ASSERT(*numProcessed == 0);
-    uint32_t initLength = Min<uint32_t>(GetBoxedOrUnboxedInitializedLength(obj), length);
+    uint32_t initLength = Min<uint32_t>(obj->as<NativeObject>().getDenseInitializedLength(),
+                                        length);
     while (*numProcessed < initLength) {
         if (!CheckForInterrupt(cx))
             return DenseElementResult::Failure;
 
-        Value elem = GetBoxedOrUnboxedDenseElement(obj, *numProcessed);
+        Value elem = obj->as<NativeObject>().getDenseElement(*numProcessed);
 
         if (elem.isString()) {
             if (!sb.append(elem.toString()))
@@ -1207,11 +1210,14 @@ js::array_join(JSContext* cx, unsigned argc, Value* vp)
     // An optimized version of a special case of steps 7-11: when length==1 and
     // the 0th element is a string, ToString() of that element is a no-op and
     // so it can be immediately returned as the result.
-    if (length == 1 && GetAnyBoxedOrUnboxedInitializedLength(obj) == 1) {
-        Value elem0 = GetAnyBoxedOrUnboxedDenseElement(obj, 0);
-        if (elem0.isString()) {
-            args.rval().set(elem0);
-            return true;
+    if (length == 1 && obj->isNative()) {
+        NativeObject* nobj = &obj->as<NativeObject>();
+        if (nobj->getDenseInitializedLength() == 1) {
+            Value elem0 = nobj->getDenseElement(0);
+            if (elem0.isString()) {
+                args.rval().set(elem0);
+                return true;
+            }
         }
     }
 
@@ -1359,7 +1365,7 @@ DenseElementResult
 ArrayReverseDenseKernel(JSContext* cx, HandleObject obj, uint32_t length)
 {
     /* An empty array or an array with no elements is already reversed. */
-    if (length == 0 || GetBoxedOrUnboxedInitializedLength(obj) == 0)
+    if (length == 0 || obj->as<NativeObject>().getDenseInitializedLength() == 0)
         return DenseElementResult::Success;
 
     if (obj->as<NativeObject>().denseElementsAreFrozen())
@@ -1385,15 +1391,15 @@ ArrayReverseDenseKernel(JSContext* cx, HandleObject obj, uint32_t length)
 
     uint32_t lo = 0, hi = length - 1;
     for (; lo < hi; lo++, hi--) {
-        origlo = GetBoxedOrUnboxedDenseElement(obj, lo);
-        orighi = GetBoxedOrUnboxedDenseElement(obj, hi);
-        SetBoxedOrUnboxedDenseElementNoTypeChange(obj, lo, orighi);
+        origlo = obj->as<NativeObject>().getDenseElement(lo);
+        orighi = obj->as<NativeObject>().getDenseElement(hi);
+        obj->as<NativeObject>().setDenseElement(lo, orighi);
         if (orighi.isMagic(JS_ELEMENTS_HOLE) &&
             !SuppressDeletedProperty(cx, obj, INT_TO_JSID(lo)))
         {
             return DenseElementResult::Failure;
         }
-        SetBoxedOrUnboxedDenseElementNoTypeChange(obj, hi, origlo);
+        obj->as<NativeObject>().setDenseElement(hi, origlo);
         if (origlo.isMagic(JS_ELEMENTS_HOLE) &&
             !SuppressDeletedProperty(cx, obj, INT_TO_JSID(hi)))
         {
@@ -2074,14 +2080,8 @@ js::array_push(JSContext* cx, unsigned argc, Value* vp)
             uint32_t newlength = length + args.length();
             args.rval().setNumber(newlength);
 
-            // SetOrExtendBoxedOrUnboxedDenseElements takes care of updating the
-            // length for boxed and unboxed arrays. Handle updates to the length of
-            // non-arrays here.
-            bool isArray;
-            if (!IsArray(cx, obj, &isArray))
-                return false;
-
-            if (!isArray)
+            // Handle updates to the length of non-arrays here.
+            if (!obj->is<ArrayObject>())
                 return SetLengthProperty(cx, obj, newlength);
 
             return true;
@@ -2141,14 +2141,15 @@ template <JSValueType Type>
 static inline DenseElementResult
 ShiftMoveBoxedOrUnboxedDenseElements(JSObject* obj)
 {
-    MOZ_ASSERT(HasBoxedOrUnboxedDenseElements(obj));
+    MOZ_ASSERT(obj->isNative());
+
+    size_t initlen = obj->as<NativeObject>().getDenseInitializedLength();
 
     /*
      * At this point the length and initialized length have already been
      * decremented and the result fetched, so just shift the array elements
      * themselves.
      */
-    size_t initlen = GetBoxedOrUnboxedInitializedLength(obj);
     obj->as<NativeObject>().moveDenseElementsNoPreBarrier(0, 1, initlen);
 
     return DenseElementResult::Success;
@@ -2165,6 +2166,15 @@ js::ArrayShiftMoveElements(JSObject* obj)
     JS_ALWAYS_TRUE(CallBoxedOrUnboxedSpecialization(functor, obj) == DenseElementResult::Success);
 }
 
+static inline void
+SetInitializedLength(JSContext* cx, NativeObject* obj, size_t initlen)
+{
+    size_t oldInitlen = obj->getDenseInitializedLength();
+    obj->setDenseInitializedLength(initlen);
+    if (initlen < oldInitlen)
+        obj->shrinkElements(cx, initlen);
+}
+
 template <JSValueType Type>
 DenseElementResult
 ArrayShiftDenseKernel(JSContext* cx, HandleObject obj, MutableHandleValue rval)
@@ -2179,11 +2189,11 @@ ArrayShiftDenseKernel(JSContext* cx, HandleObject obj, MutableHandleValue rval)
     if (MOZ_UNLIKELY(group->hasAllFlags(OBJECT_FLAG_ITERATED)))
         return DenseElementResult::Incomplete;
 
-    size_t initlen = GetBoxedOrUnboxedInitializedLength(obj);
+    size_t initlen = obj->as<NativeObject>().getDenseInitializedLength();
     if (initlen == 0)
         return DenseElementResult::Incomplete;
 
-    rval.set(GetBoxedOrUnboxedDenseElement(obj, 0));
+    rval.set(obj->as<NativeObject>().getDenseElement(0));
     if (rval.isMagic(JS_ELEMENTS_HOLE))
         rval.setUndefined();
 
@@ -2191,7 +2201,7 @@ ArrayShiftDenseKernel(JSContext* cx, HandleObject obj, MutableHandleValue rval)
     if (result != DenseElementResult::Success)
         return result;
 
-    SetBoxedOrUnboxedInitializedLength(cx, obj, initlen - 1);
+    SetInitializedLength(cx, obj.as<NativeObject>(), initlen - 1);
     return DenseElementResult::Success;
 }
 
@@ -2364,7 +2374,7 @@ CanOptimizeForDenseStorage(HandleObject arr, uint32_t startingIndex, uint32_t co
         return false;
 
     /* If it's a frozen array, always pick the slow path */
-    if (arr->is<ArrayObject>() && arr->as<ArrayObject>().denseElementsAreFrozen())
+    if (arr->as<ArrayObject>().denseElementsAreFrozen())
         return false;
 
     /*
@@ -2396,7 +2406,7 @@ CanOptimizeForDenseStorage(HandleObject arr, uint32_t startingIndex, uint32_t co
      * is subsumed by the initializedLength comparison.)
      */
     return !ObjectMayHaveExtraIndexedProperties(arr) &&
-           startingIndex + count <= GetAnyBoxedOrUnboxedInitializedLength(arr);
+           startingIndex + count <= arr->as<NativeObject>().getDenseInitializedLength();
 }
 
 /* ES 2016 draft Mar 25, 2016 22.1.3.26. */
@@ -2541,7 +2551,7 @@ js::array_splice_impl(JSContext* cx, unsigned argc, Value* vp, bool returnValueI
                 return false;
 
             /* Steps 15.c-d. */
-            SetBoxedOrUnboxedInitializedLength(cx, obj, finalLength);
+            SetInitializedLength(cx, obj.as<NativeObject>(), finalLength);
         } else {
             /*
              * This is all very slow if the length is very large. We don't yet
@@ -2629,7 +2639,7 @@ js::array_splice_impl(JSContext* cx, unsigned argc, Value* vp, bool returnValueI
                 return false;
 
             /* Steps 16.a-b. */
-            SetBoxedOrUnboxedInitializedLength(cx, obj, len + itemCount - actualDeleteCount);
+            SetInitializedLength(cx, obj.as<NativeObject>(), len + itemCount - actualDeleteCount);
         } else {
             RootedValue fromValue(cx);
             for (double k = len - actualDeleteCount; k > actualStart; k--) {
@@ -2851,7 +2861,7 @@ ArraySliceOrdinary(JSContext* cx, HandleObject obj, uint32_t length, uint32_t be
         begin = end;
 
     if (!ObjectMayHaveExtraIndexedProperties(obj)) {
-        size_t initlen = GetAnyBoxedOrUnboxedInitializedLength(obj);
+        size_t initlen = obj->as<NativeObject>().getDenseInitializedLength();
         size_t count = 0;
         if (initlen > begin)
             count = Min<size_t>(initlen - begin, end - begin);
@@ -2859,7 +2869,9 @@ ArraySliceOrdinary(JSContext* cx, HandleObject obj, uint32_t length, uint32_t be
         RootedObject narr(cx, NewFullyAllocatedArrayTryReuseGroup(cx, obj, count));
         if (!narr)
             return false;
-        SetAnyBoxedOrUnboxedArrayLength(cx, narr, end - begin);
+
+        MOZ_ASSERT(count >= narr->as<ArrayObject>().length());
+        narr->as<ArrayObject>().setLength(cx, count);
 
         if (count) {
             DebugOnly<DenseElementResult> result =
@@ -2991,7 +3003,7 @@ template <JSValueType Type>
 DenseElementResult
 ArraySliceDenseKernel(JSContext* cx, JSObject* obj, int32_t beginArg, int32_t endArg, JSObject* result)
 {
-    int32_t length = GetAnyBoxedOrUnboxedArrayLength(obj);
+    int32_t length = obj->as<ArrayObject>().length();
 
     uint32_t begin = NormalizeSliceTerm(beginArg, length);
     uint32_t end = NormalizeSliceTerm(endArg, length);
@@ -2999,18 +3011,19 @@ ArraySliceDenseKernel(JSContext* cx, JSObject* obj, int32_t beginArg, int32_t en
     if (begin > end)
         begin = end;
 
-    size_t initlen = GetBoxedOrUnboxedInitializedLength(obj);
+    size_t initlen = obj->as<NativeObject>().getDenseInitializedLength();
+    size_t count = Min<size_t>(initlen - begin, end - begin);
     if (initlen > begin) {
-        size_t count = Min<size_t>(initlen - begin, end - begin);
         if (count) {
-            DenseElementResult rv = EnsureBoxedOrUnboxedDenseElements(cx, result, count);
-            if (rv != DenseElementResult::Success)
-                return rv;
+            if (!result->as<ArrayObject>().ensureElements(cx, count))
+                return DenseElementResult::Failure;
             CopyBoxedOrUnboxedDenseElements(cx, result, obj, 0, begin, count);
         }
     }
 
-    SetAnyBoxedOrUnboxedArrayLength(cx, result, end - begin);
+    MOZ_ASSERT(count >= result->as<ArrayObject>().length());
+    result->as<ArrayObject>().setLength(cx, count);
+
     return DenseElementResult::Success;
 }
 
diff --git a/js/src/jsobj.cpp b/js/src/jsobj.cpp
index c26a42f48..deaa1d53e 100644
--- a/js/src/jsobj.cpp
+++ b/js/src/jsobj.cpp
@@ -1143,19 +1143,18 @@ js::CloneObject(JSContext* cx, HandleObject obj, Handle<js::TaggedProto> proto)
 }
 
 static bool
-GetScriptArrayObjectElements(JSContext* cx, HandleObject obj, MutableHandle<GCVector<Value>> values)
+GetScriptArrayObjectElements(JSContext* cx, HandleArrayObject arr, MutableHandle<GCVector<Value>> values)
 {
-    MOZ_ASSERT(!obj->isSingleton());
-    MOZ_ASSERT(obj->is<ArrayObject>());
-    MOZ_ASSERT(!obj->isIndexed());
+    MOZ_ASSERT(!arr->isSingleton());
+    MOZ_ASSERT(!arr->isIndexed());
 
-    size_t length = GetAnyBoxedOrUnboxedArrayLength(obj);
+    size_t length = arr->length();
     if (!values.appendN(MagicValue(JS_ELEMENTS_HOLE), length))
         return false;
 
-    size_t initlen = GetAnyBoxedOrUnboxedInitializedLength(obj);
+    size_t initlen = arr->getDenseInitializedLength();
     for (size_t i = 0; i < initlen; i++)
-        values[i].set(GetAnyBoxedOrUnboxedDenseElement(obj, i));
+        values[i].set(arr->getDenseElement(i));
 
     return true;
 }
@@ -1212,7 +1211,7 @@ js::DeepCloneObjectLiteral(JSContext* cx, HandleObject obj, NewObjectKind newKin
 
     if (obj->is<ArrayObject>()) {
         Rooted<GCVector<Value>> values(cx, GCVector<Value>(cx));
-        if (!GetScriptArrayObjectElements(cx, obj, &values))
+        if (!GetScriptArrayObjectElements(cx, obj.as<ArrayObject>(), &values))
             return nullptr;
 
         // Deep clone any elements.
@@ -1339,8 +1338,11 @@ js::XDRObjectLiteral(XDRState<mode>* xdr, MutableHandleObject obj)
 
     if (isArray) {
         Rooted<GCVector<Value>> values(cx, GCVector<Value>(cx));
-        if (mode == XDR_ENCODE && !GetScriptArrayObjectElements(cx, obj, &values))
-            return false;
+        if (mode == XDR_ENCODE) {
+            RootedArrayObject arr(cx, &obj->as<ArrayObject>());
+            if (!GetScriptArrayObjectElements(cx, arr, &values))
+                return false;
+        }
 
         uint32_t initialized;
         if (mode == XDR_ENCODE)
diff --git a/js/src/vm/UnboxedObject-inl.h b/js/src/vm/UnboxedObject-inl.h
index 499f3604b..b308464fe 100644
--- a/js/src/vm/UnboxedObject-inl.h
+++ b/js/src/vm/UnboxedObject-inl.h
@@ -173,129 +173,9 @@ UnboxedPlainObject::layout() const
 }
 
 /////////////////////////////////////////////////////////////////////
-// Combined methods for NativeObject and UnboxedArrayObject accesses.
-/////////////////////////////////////////////////////////////////////
-
-static inline bool
-HasAnyBoxedOrUnboxedDenseElements(JSObject* obj)
-{
-    return obj->isNative();
-}
-
-static inline size_t
-GetAnyBoxedOrUnboxedInitializedLength(JSObject* obj)
-{
-    if (obj->isNative())
-        return obj->as<NativeObject>().getDenseInitializedLength();
-    return 0;
-}
-
-static inline size_t
-GetAnyBoxedOrUnboxedCapacity(JSObject* obj)
-{
-    if (obj->isNative())
-        return obj->as<NativeObject>().getDenseCapacity();
-    return 0;
-}
-
-static inline Value
-GetAnyBoxedOrUnboxedDenseElement(JSObject* obj, size_t index)
-{
-    return obj->as<NativeObject>().getDenseElement(index);
-}
-
-static inline size_t
-GetAnyBoxedOrUnboxedArrayLength(JSObject* obj)
-{
-    return obj->as<ArrayObject>().length();
-}
-
-static inline void
-SetAnyBoxedOrUnboxedArrayLength(JSContext* cx, JSObject* obj, size_t length)
-{
-    MOZ_ASSERT(length >= obj->as<ArrayObject>().length());
-    obj->as<ArrayObject>().setLength(cx, length);
-}
-
-static inline bool
-SetAnyBoxedOrUnboxedDenseElement(JSContext* cx, JSObject* obj, size_t index, const Value& value)
-{
-    obj->as<NativeObject>().setDenseElementWithType(cx, index, value);
-    return true;
-}
-
-static inline bool
-InitAnyBoxedOrUnboxedDenseElement(JSContext* cx, JSObject* obj, size_t index, const Value& value)
-{
-    obj->as<NativeObject>().initDenseElementWithType(cx, index, value);
-    return true;
-}
-
-/////////////////////////////////////////////////////////////////////
 // Template methods for NativeObject and UnboxedArrayObject accesses.
 /////////////////////////////////////////////////////////////////////
 
-static inline JSValueType
-GetBoxedOrUnboxedType(JSObject* obj)
-{
-    return JSVAL_TYPE_MAGIC;
-}
-
-static inline bool
-HasBoxedOrUnboxedDenseElements(JSObject* obj)
-{
-    return obj->isNative();
-}
-
-static inline size_t
-GetBoxedOrUnboxedInitializedLength(JSObject* obj)
-{
-    return obj->as<NativeObject>().getDenseInitializedLength();
-}
-
-static inline DenseElementResult
-SetBoxedOrUnboxedInitializedLength(JSContext* cx, JSObject* obj, size_t initlen)
-{
-	size_t oldInitlen = GetBoxedOrUnboxedInitializedLength(obj);
-    obj->as<NativeObject>().setDenseInitializedLength(initlen);
-    if (initlen < oldInitlen)
-        obj->as<NativeObject>().shrinkElements(cx, initlen);
-    return DenseElementResult::Success;
-}
-
-static inline size_t
-GetBoxedOrUnboxedCapacity(JSObject* obj)
-{
-    return obj->as<NativeObject>().getDenseCapacity();
-}
-
-static inline Value
-GetBoxedOrUnboxedDenseElement(JSObject* obj, size_t index)
-{
-    return obj->as<NativeObject>().getDenseElement(index);
-}
-
-static inline void
-SetBoxedOrUnboxedDenseElementNoTypeChange(JSObject* obj, size_t index, const Value& value)
-{
-    obj->as<NativeObject>().setDenseElement(index, value);
-}
-
-static inline bool
-SetBoxedOrUnboxedDenseElement(JSContext* cx, JSObject* obj, size_t index, const Value& value)
-{
-    obj->as<NativeObject>().setDenseElementWithType(cx, index, value);
-    return true;
-}
-
-static inline DenseElementResult
-EnsureBoxedOrUnboxedDenseElements(JSContext* cx, JSObject* obj, size_t count)
-{
-    if (!obj->as<ArrayObject>().ensureElements(cx, count))
-        return DenseElementResult::Failure;
-    return DenseElementResult::Success;
-}
-
 static inline DenseElementResult
 SetOrExtendBoxedOrUnboxedDenseElements(ExclusiveContext* cx, JSObject* obj,
                                        uint32_t start, const Value* vp, uint32_t count,
@@ -334,7 +214,7 @@ static inline DenseElementResult
 MoveBoxedOrUnboxedDenseElements(JSContext* cx, JSObject* obj, uint32_t dstStart, uint32_t srcStart,
                                 uint32_t length)
 {
-    MOZ_ASSERT(HasBoxedOrUnboxedDenseElements(obj));
+    MOZ_ASSERT(obj->isNative());
 
     if (obj->as<NativeObject>().denseElementsAreFrozen())
         return DenseElementResult::Incomplete;
@@ -350,13 +230,13 @@ static inline DenseElementResult
 CopyBoxedOrUnboxedDenseElements(JSContext* cx, JSObject* dst, JSObject* src,
                                 uint32_t dstStart, uint32_t srcStart, uint32_t length)
 {
-    MOZ_ASSERT(HasBoxedOrUnboxedDenseElements(src));
-    MOZ_ASSERT(HasBoxedOrUnboxedDenseElements(dst));
-    MOZ_ASSERT(GetBoxedOrUnboxedInitializedLength(dst) == dstStart);
-    MOZ_ASSERT(GetBoxedOrUnboxedInitializedLength(src) >= srcStart + length);
-    MOZ_ASSERT(GetBoxedOrUnboxedCapacity(dst) >= dstStart + length);
+    MOZ_ASSERT(src->isNative());
+    MOZ_ASSERT(dst->isNative());
+    MOZ_ASSERT(dst->as<NativeObject>().getDenseInitializedLength() == dstStart);
+    MOZ_ASSERT(src->as<NativeObject>().getDenseInitializedLength() >= srcStart + length);
+    MOZ_ASSERT(dst->as<NativeObject>().getDenseCapacity() >= dstStart + length);
 
-    SetBoxedOrUnboxedInitializedLength(cx, dst, dstStart + length);
+    dst->as<NativeObject>().setDenseInitializedLength(dstStart + length);
 
     const Value* vp = src->as<NativeObject>().getDenseElements() + srcStart;
     dst->as<NativeObject>().initDenseElements(dstStart, vp, length);
@@ -383,7 +263,7 @@ template <typename F>
 DenseElementResult
 CallBoxedOrUnboxedSpecialization(F f, JSObject* obj)
 {
-    if (!HasAnyBoxedOrUnboxedDenseElements(obj))
+    if (!obj->isNative())
         return DenseElementResult::Incomplete;
     return f. DEPENDENT_TEMPLATE_HINT operator()<JSVAL_TYPE_MAGIC>();
 }
@@ -393,7 +273,7 @@ template <typename F>
 DenseElementResult
 CallBoxedOrUnboxedSpecialization(F f, JSObject* obj1, JSObject* obj2)
 {
-    if (!HasAnyBoxedOrUnboxedDenseElements(obj1) || !HasAnyBoxedOrUnboxedDenseElements(obj2))
+    if (!obj1->isNative() || !obj2->isNative())
         return DenseElementResult::Incomplete;
 
     return f. DEPENDENT_TEMPLATE_HINT operator()<JSVAL_TYPE_MAGIC, JSVAL_TYPE_MAGIC>();