Alternative approach to using type feedback for Symbol-keyed properties

src/type-feedback-vector.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/type-feedback-vector.h"
 
 #include "src/code-stubs.h"
 #include "src/ic/ic.h"
 #include "src/ic/ic-state.h"
 #include "src/objects.h"
 #include "src/type-feedback-vector-inl.h"
 
 namespace v8 {
 namespace internal {
 
+
+static bool IsPropertyNameFeedback(Object* feedback) {
+  return feedback->IsString() ||
+         (feedback->IsSymbol() && !Symbol::cast(feedback)->is_private());
+}
+
+
 std::ostream& operator<<(std::ostream& os, FeedbackVectorSlotKind kind) {
   return os << TypeFeedbackMetadata::Kind2String(kind);
 }
 
 
 FeedbackVectorSlotKind TypeFeedbackMetadata::GetKind(
     FeedbackVectorSlot slot) const {
   int index = VectorICComputer::index(kReservedIndexCount, slot.ToInt());
   int data = Smi::cast(get(index))->value();
   return VectorICComputer::decode(data, slot.ToInt());
@@ skipping 617 matching lines @@
       array->set((i * 3) + 1, *undefined_value);
     }
     array->set((i * 3) + 2, *handlers->at(i));
   }
 }
 
 
 int FeedbackNexus::ExtractMaps(MapHandleList* maps) const {
   Isolate* isolate = GetIsolate();
   Object* feedback = GetFeedback();
-  if (feedback->IsFixedArray() || feedback->IsString()) {
+  bool is_named_feedback = IsPropertyNameFeedback(feedback);
+  if (feedback->IsFixedArray() || is_named_feedback) {
     int found = 0;
-    if (feedback->IsString()) {
+    if (is_named_feedback) {
       feedback = GetFeedbackExtra();
     }
     FixedArray* array = FixedArray::cast(feedback);
     // The array should be of the form
     // [map, handler, map, handler, ...]
     // or
     // [map, map, handler, map, map, handler, ...]
     DCHECK(array->length() >= 2);
     int increment = array->get(1)->IsCode() ? 2 : 3;
     for (int i = 0; i < array->length(); i += increment) {
@@ skipping 14 matching lines @@
       return 1;
     }
   }
 
   return 0;
 }
 
 
 MaybeHandle<Code> FeedbackNexus::FindHandlerForMap(Handle<Map> map) const {
   Object* feedback = GetFeedback();
-  if (feedback->IsFixedArray() || feedback->IsString()) {
-    if (feedback->IsString()) {
+  bool is_named_feedback = IsPropertyNameFeedback(feedback);
+  if (feedback->IsFixedArray() || is_named_feedback) {
+    if (is_named_feedback) {
       feedback = GetFeedbackExtra();
     }
     FixedArray* array = FixedArray::cast(feedback);
     DCHECK(array->length() >= 2);
     int increment = array->get(1)->IsCode() ? 2 : 3;
     for (int i = 0; i < array->length(); i += increment) {
       DCHECK(array->get(i)->IsWeakCell());
       WeakCell* cell = WeakCell::cast(array->get(i));
       if (!cell->cleared()) {
         Map* array_map = Map::cast(cell->value());
@@ skipping 16 matching lines @@
     }
   }
 
   return MaybeHandle<Code>();
 }
 
 
 bool FeedbackNexus::FindHandlers(CodeHandleList* code_list, int length) const {
   Object* feedback = GetFeedback();
   int count = 0;
-  if (feedback->IsFixedArray() || feedback->IsString()) {
-    if (feedback->IsString()) {
+  bool is_named_feedback = IsPropertyNameFeedback(feedback);
+  if (feedback->IsFixedArray() || is_named_feedback) {
+    if (is_named_feedback) {
       feedback = GetFeedbackExtra();
     }
     FixedArray* array = FixedArray::cast(feedback);
     // The array should be of the form
     // [map, handler, map, handler, ...]
     // or
     // [map, map, handler, map, map, handler, ...]
     // Be sure to skip handlers whose maps have been cleared.
     DCHECK(array->length() >= 2);
     int increment = array->get(1)->IsCode() ? 2 : 3;
@@ skipping 23 matching lines @@
 void LoadICNexus::Clear(Code* host) { LoadIC::Clear(GetIsolate(), host, this); }
 
 
 void KeyedLoadICNexus::Clear(Code* host) {
   KeyedLoadIC::Clear(GetIsolate(), host, this);
 }
 
 
 Name* KeyedLoadICNexus::FindFirstName() const {
   Object* feedback = GetFeedback();
-  if (feedback->IsString()) {
+  if (IsPropertyNameFeedback(feedback)) {
     return Name::cast(feedback);
   }
   return NULL;
 }
 
 
 Name* KeyedStoreICNexus::FindFirstName() const {
   Object* feedback = GetFeedback();
-  if (feedback->IsString()) {
+  if (IsPropertyNameFeedback(feedback)) {
     return Name::cast(feedback);
   }
   return NULL;
 }
 
 
 void StoreICNexus::Clear(Code* host) {
   StoreIC::Clear(GetIsolate(), host, this);
 }
 
@@ skipping 31 matching lines @@
   return mode;
 }
 
 
 IcCheckType KeyedStoreICNexus::GetKeyType() const {
   // The structure of the vector slots tells us the type.
   return GetFeedback()->IsName() ? PROPERTY : ELEMENT;
 }
 }  // namespace internal
 }  // namespace v8