[elements] Use IsHoleyElementsKind if possible

Bug: v8:6922
Change-Id: I641f654f0548c2da24cdea3ffd275461ae8ce9b0
Reviewed-on: https://chromium-review.googlesource.com/1172776Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55098}

src/elements-kind.cc

@@ -130,29 +130,27 @@ static inline bool IsFastTransitionTarget(ElementsKind elements_kind) {
 
 bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
                                          ElementsKind to_kind) {
-  if (IsFastElementsKind(from_kind) && IsFastTransitionTarget(to_kind)) {
-    DCHECK(!IsFixedTypedArrayElementsKind(from_kind));
-    DCHECK(!IsFixedTypedArrayElementsKind(to_kind));
-    switch (from_kind) {
-      case PACKED_SMI_ELEMENTS:
-        return to_kind != PACKED_SMI_ELEMENTS;
-      case HOLEY_SMI_ELEMENTS:
-        return to_kind != PACKED_SMI_ELEMENTS && to_kind != HOLEY_SMI_ELEMENTS;
-      case PACKED_DOUBLE_ELEMENTS:
-        return to_kind != PACKED_SMI_ELEMENTS &&
-               to_kind != HOLEY_SMI_ELEMENTS &&
-               to_kind != PACKED_DOUBLE_ELEMENTS;
-      case HOLEY_DOUBLE_ELEMENTS:
-        return to_kind == PACKED_ELEMENTS || to_kind == HOLEY_ELEMENTS;
-      case PACKED_ELEMENTS:
-        return to_kind == HOLEY_ELEMENTS;
-      case HOLEY_ELEMENTS:
-        return false;
-      default:
-        return false;
-    }
+  if (!IsFastElementsKind(from_kind)) return false;
+  if (!IsFastTransitionTarget(to_kind)) return false;
+  DCHECK(!IsFixedTypedArrayElementsKind(from_kind));
+  DCHECK(!IsFixedTypedArrayElementsKind(to_kind));
+  switch (from_kind) {
+    case PACKED_SMI_ELEMENTS:
+      return to_kind != PACKED_SMI_ELEMENTS;
+    case HOLEY_SMI_ELEMENTS:
+      return to_kind != PACKED_SMI_ELEMENTS && to_kind != HOLEY_SMI_ELEMENTS;
+    case PACKED_DOUBLE_ELEMENTS:
+      return to_kind != PACKED_SMI_ELEMENTS && to_kind != HOLEY_SMI_ELEMENTS &&
+             to_kind != PACKED_DOUBLE_ELEMENTS;
+    case HOLEY_DOUBLE_ELEMENTS:
+      return to_kind == PACKED_ELEMENTS || to_kind == HOLEY_ELEMENTS;
+    case PACKED_ELEMENTS:
+      return to_kind == HOLEY_ELEMENTS;
+    case HOLEY_ELEMENTS:
+      return false;
+    default:
+      return false;
   }
-  return false;
 }
 
 bool UnionElementsKindUptoSize(ElementsKind* a_out, ElementsKind b) {

src/elements.cc

@@ -602,7 +602,7 @@ class ElementsAccessorBase : public InternalElementsAccessor {
   }
 
   static void TryTransitionResultArrayToPacked(Handle<JSArray> array) {
-    if (!IsHoleyOrDictionaryElementsKind(kind())) return;
+    if (!IsHoleyElementsKind(kind())) return;
     Handle<FixedArrayBase> backing_store(array->elements(),
                                          array->GetIsolate());
     int length = Smi::ToInt(array->length());
@@ -937,7 +937,7 @@ class ElementsAccessorBase : public InternalElementsAccessor {
     Handle<FixedArrayBase> elements =
         ConvertElementsWithCapacity(object, old_elements, from_kind, capacity);
 
-    if (IsHoleyOrDictionaryElementsKind(from_kind)) {
+    if (IsHoleyElementsKind(from_kind)) {
       to_kind = GetHoleyElementsKind(to_kind);
     }
     Handle<Map> new_map = JSObject::GetElementsTransitionMap(object, to_kind);

src/lookup.cc

@@ -398,7 +398,7 @@ void LookupIterator::PrepareForDataProperty(Handle<Object> value) {
   if (IsElement()) {
     ElementsKind kind = holder_obj->GetElementsKind();
     ElementsKind to = value->OptimalElementsKind();
-    if (IsHoleyOrDictionaryElementsKind(kind)) to = GetHoleyElementsKind(to);
+    if (IsHoleyElementsKind(kind)) to = GetHoleyElementsKind(to);
     to = GetMoreGeneralElementsKind(kind, to);
 
     if (kind != to) {

src/objects.cc

@@ -5656,7 +5656,7 @@ Handle<Map> Map::TransitionElementsTo(Isolate* isolate, Handle<Map> map,
 
   DCHECK(!map->IsUndefined(isolate));
   // Check if we can go back in the elements kind transition chain.
-  if (IsHoleyOrDictionaryElementsKind(from_kind) &&
+  if (IsHoleyElementsKind(from_kind) &&
       to_kind == GetPackedElementsKind(from_kind) &&
       map->GetBackPointer()->IsMap() &&
       Map::cast(map->GetBackPointer())->elements_kind() == to_kind) {
@@ -15724,8 +15724,7 @@ void JSObject::AddDataElement(Handle<JSObject> object, uint32_t index,
   }
 
   ElementsKind to = value->OptimalElementsKind();
-  if (IsHoleyOrDictionaryElementsKind(kind) || !object->IsJSArray() ||
-      index > old_length) {
+  if (IsHoleyElementsKind(kind) || !object->IsJSArray() || index > old_length) {
     to = GetHoleyElementsKind(to);
     kind = GetHoleyElementsKind(kind);
   }
@@ -15789,7 +15788,7 @@ bool AllocationSite::DigestTransitionFeedback(Handle<AllocationSite> site,
     Handle<JSArray> boilerplate(JSArray::cast(site->boilerplate()), isolate);
     ElementsKind kind = boilerplate->GetElementsKind();
     // if kind is holey ensure that to_kind is as well.
-    if (IsHoleyOrDictionaryElementsKind(kind)) {
+    if (IsHoleyElementsKind(kind)) {
       to_kind = GetHoleyElementsKind(to_kind);
     }
     if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {
@@ -15817,7 +15816,7 @@ bool AllocationSite::DigestTransitionFeedback(Handle<AllocationSite> site,
     // The AllocationSite is for a constructed Array.
     ElementsKind kind = site->GetElementsKind();
     // if kind is holey ensure that to_kind is as well.
-    if (IsHoleyOrDictionaryElementsKind(kind)) {
+    if (IsHoleyElementsKind(kind)) {
       to_kind = GetHoleyElementsKind(to_kind);
     }
     if (IsMoreGeneralElementsKindTransition(kind, to_kind)) {