Correct handling of arrays with callbacks in the prototype chain.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6212 matching lines @@
       return !AccessorInfo::cast(obj)->prohibits_overwriting();
     }
     if (obj->IsAccessorPair()) {
       return !AccessorPair::cast(obj)->prohibits_overwriting();
     }
   }
   return true;
 }
 
 
+bool Map::DictionaryElementsInPrototypeChain() {
+  Heap* heap = GetHeap();
+
+  if (IsDictionaryElementsKind(elements_kind())) {
+    return true;
+  }
+
+  for (Object* prototype = this->prototype();
+       prototype != heap->null_value();
+       prototype = prototype->GetPrototype(GetIsolate())) {
+    if (prototype->IsJSProxy()) {
+      // Be conservative, don't walk into proxies.
+      return true;
+    }
+
+    if (IsDictionaryElementsKind(
+            JSObject::cast(prototype)->map()->elements_kind())) {
+      return true;
+    }
+  }
+
+  return false;
+}
+

[danno, 2013/11/04 17:44:44]

nit: two returns between functions

[mvstanton, 2013/11/05 09:06:51]

Done.

 void JSObject::SetElementCallback(Handle<JSObject> object,
                                   uint32_t index,
                                   Handle<Object> structure,
                                   PropertyAttributes attributes) {
   Heap* heap = object->GetHeap();
   PropertyDetails details = PropertyDetails(attributes, CALLBACKS, 0);
 
   // Normalize elements to make this operation simple.
   Handle<SeededNumberDictionary> dictionary = NormalizeElements(object);
   ASSERT(object->HasDictionaryElements() ||
@@ skipping 4327 matching lines @@
     if (--n == 0) {
       info->set_target_cell(replace_with);
       return;
     }
   }
   UNREACHABLE();
 }
 
 
 void Code::ClearInlineCaches() {
+  ClearInlineCaches(NULL);
+}
+
+
+void Code::ClearInlineCaches(Code::Kind kind) {
+  ClearInlineCaches(&kind);
+}
+
+
+void Code::ClearInlineCaches(Code::Kind* kind) {
   int mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET) |
              RelocInfo::ModeMask(RelocInfo::CONSTRUCT_CALL) |
              RelocInfo::ModeMask(RelocInfo::CODE_TARGET_WITH_ID) |
              RelocInfo::ModeMask(RelocInfo::CODE_TARGET_CONTEXT);
   for (RelocIterator it(this, mask); !it.done(); it.next()) {
     RelocInfo* info = it.rinfo();
     Code* target(Code::GetCodeFromTargetAddress(info->target_address()));
     if (target->is_inline_cache_stub()) {
-      IC::Clear(this->GetIsolate(), info->pc());
+      if (kind == NULL || *kind == target->kind()) {
+        IC::Clear(this->GetIsolate(), info->pc());
+      }
     }
   }
 }
 
 
 void Code::ClearTypeFeedbackCells(Heap* heap) {
   if (kind() != FUNCTION) return;
   Object* raw_info = type_feedback_info();
   if (raw_info->IsTypeFeedbackInfo()) {
     TypeFeedbackCells* type_feedback_cells =
@@ skipping 1152 matching lines @@
        pt = pt->GetPrototype(isolate)) {
     if (JSReceiver::cast(pt) == *object) {
       // Cycle detected.
       Handle<Object> error = isolate->factory()->NewError(
           "cyclic_proto", HandleVector<Object>(NULL, 0));
       isolate->Throw(*error);
       return Handle<Object>();
     }
   }
 
+  bool dictionary_elements_in_chain =
+      object->map()->DictionaryElementsInPrototypeChain();
   Handle<JSObject> real_receiver = object;
 
   if (skip_hidden_prototypes) {
     // Find the first object in the chain whose prototype object is not
     // hidden and set the new prototype on that object.
     Object* current_proto = real_receiver->GetPrototype();
     while (current_proto->IsJSObject() &&
           JSObject::cast(current_proto)->map()->is_hidden_prototype()) {
       real_receiver = handle(JSObject::cast(current_proto), isolate);
       current_proto = current_proto->GetPrototype(isolate);
@@ skipping 12 matching lines @@
 
   Handle<Map> new_map = Map::GetPrototypeTransition(map, value);
   if (new_map.is_null()) {
     new_map = Map::Copy(map);
     Map::PutPrototypeTransition(map, value, new_map);
     new_map->set_prototype(*value);
   }
   ASSERT(new_map->prototype() == *value);
   real_receiver->set_map(*new_map);
 
+  if (!dictionary_elements_in_chain &&
+      new_map->DictionaryElementsInPrototypeChain()) {
+    // If the prototype chain didn't previously have element callbacks, then
+    // KeyedStoreICs need to be cleared to ensure any that involve this
+    // map go generic.
+    object->GetHeap()->ClearAllICsByKind(Code::KEYED_STORE_IC);
+  }
+
   heap->ClearInstanceofCache();
   ASSERT(size == object->Size());
   return value;
 }
 
 
 MaybeObject* JSObject::EnsureCanContainElements(Arguments* args,
                                                 uint32_t first_arg,
                                                 uint32_t arg_count,
                                                 EnsureElementsMode mode) {
@@ skipping 968 matching lines @@
 
 MaybeObject* JSObject::TransitionElementsKind(ElementsKind to_kind) {
   ASSERT(!map()->is_observed());
   ElementsKind from_kind = map()->elements_kind();
 
   if (IsFastHoleyElementsKind(from_kind)) {
     to_kind = GetHoleyElementsKind(to_kind);
   }
 
   if (from_kind == to_kind) return this;
-
-  MaybeObject* maybe_failure = UpdateAllocationSite(to_kind);
-  if (maybe_failure->IsFailure()) return maybe_failure;
+  // Don't update the site if to_kind isn't fast
+  if (IsFastElementsKind(to_kind)) {
+    MaybeObject* maybe_failure = UpdateAllocationSite(to_kind);
+    if (maybe_failure->IsFailure()) return maybe_failure;
+  }
 
   Isolate* isolate = GetIsolate();
   if (elements() == isolate->heap()->empty_fixed_array() ||
       (IsFastSmiOrObjectElementsKind(from_kind) &&
        IsFastSmiOrObjectElementsKind(to_kind)) ||
       (from_kind == FAST_DOUBLE_ELEMENTS &&
        to_kind == FAST_HOLEY_DOUBLE_ELEMENTS)) {
     ASSERT(from_kind != TERMINAL_FAST_ELEMENTS_KIND);
     // No change is needed to the elements() buffer, the transition
     // only requires a map change.
@@ skipping 3602 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal