Unify GetElement handlers in ElementsAccessor

src/elements.cc

 // Copyright 2011 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 55 matching lines @@
 //   }
 //
 // This is an example of the Curiously Recurring Template Pattern (see
 // http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern).  We use
 // CRTP to guarantee aggressive compile time optimizations (i.e.  inlining and
 // specialization of SomeElementsAccessor methods).
 template <typename ElementsAccessorSubclass, typename BackingStoreClass>
 class ElementsAccessorBase : public ElementsAccessor {
  protected:
   ElementsAccessorBase() { }
-  virtual MaybeObject* GetWithReceiver(JSObject* obj,
-                                       Object* receiver,
-                                       uint32_t key) {
-    BackingStoreClass* backing_store = BackingStoreClass::cast(obj->elements());
+  virtual MaybeObject* Get(FixedArrayBase* backing_store,
+                           uint32_t key,
+                           JSObject* obj,
+                           Object* receiver) {
+    return ElementsAccessorSubclass::Get(
+        BackingStoreClass::cast(backing_store), key, obj, receiver);
+  }
+
+  static MaybeObject* Get(BackingStoreClass* backing_store,
+                          uint32_t key,
+                          JSObject* obj,
+                          Object* receiver) {
     if (key < ElementsAccessorSubclass::GetCapacity(backing_store)) {
       return backing_store->get(key);
     }
-    return obj->GetHeap()->the_hole_value();
+    return backing_store->GetHeap()->the_hole_value();
   }
 
   virtual MaybeObject* Delete(JSObject* obj,
                               uint32_t key,
                               JSReceiver::DeleteMode mode) = 0;
 
   virtual MaybeObject* AddElementsToFixedArray(FixedArrayBase* from,
-                                               FixedArray* to) {
+                                               FixedArray* to,
+                                               JSObject* holder,
+                                               Object* receiver) {
     int len0 = to->length();
 #ifdef DEBUG
     if (FLAG_enable_slow_asserts) {
       for (int i = 0; i < len0; i++) {
         ASSERT(!to->get(i)->IsTheHole());
       }
     }
 #endif
     BackingStoreClass* backing_store = BackingStoreClass::cast(from);
     uint32_t len1 = ElementsAccessorSubclass::GetCapacity(backing_store);
 
     // Optimize if 'other' is empty.
     // We cannot optimize if 'this' is empty, as other may have holes.
     if (len1 == 0) return to;
 
     // Compute how many elements are not in other.
     int extra = 0;
     for (uint32_t y = 0; y < len1; y++) {
-      if (ElementsAccessorSubclass::HasElementAtIndex(backing_store, y)) {
+      if (ElementsAccessorSubclass::HasElementAtIndex(backing_store,
+                                                      y,
+                                                      holder,
+                                                      receiver)) {
         uint32_t key =
             ElementsAccessorSubclass::GetKeyForIndex(backing_store, y);
         MaybeObject* maybe_value =
-            ElementsAccessorSubclass::GetElement(backing_store, key);
+            ElementsAccessorSubclass::Get(backing_store, key, holder, receiver);
         Object* value;
         if (!maybe_value->ToObject(&value)) return maybe_value;
         ASSERT(!value->IsTheHole());
         if (!HasKey(to, value)) {
           extra++;
         }
       }
     }
 
     if (extra == 0) return to;
@@ skipping 10 matching lines @@
       WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
       for (int i = 0; i < len0; i++) {
         Object* e = to->get(i);
         ASSERT(e->IsString() || e->IsNumber());
         result->set(i, e, mode);
       }
     }
     // Fill in the extra values.
     int index = 0;
     for (uint32_t y = 0; y < len1; y++) {
-      if (ElementsAccessorSubclass::HasElementAtIndex(backing_store, y)) {
+      if (ElementsAccessorSubclass::HasElementAtIndex(backing_store,
+                                                      y,
+                                                      holder,
+                                                      receiver)) {
         uint32_t key =
             ElementsAccessorSubclass::GetKeyForIndex(backing_store, y);
         MaybeObject* maybe_value =
-            ElementsAccessorSubclass::GetElement(backing_store, key);
+            ElementsAccessorSubclass::Get(backing_store, key, holder, receiver);
         Object* value;
         if (!maybe_value->ToObject(&value)) return maybe_value;
         if (!value->IsTheHole() && !HasKey(to, value)) {
           result->set(len0 + index, value);
           index++;
         }
       }
     }
     ASSERT(extra == index);
     return result;
   }
 
  protected:
   static uint32_t GetCapacity(BackingStoreClass* backing_store) {
     return backing_store->length();
   }
 
   virtual uint32_t GetCapacity(FixedArrayBase* backing_store) {
     return ElementsAccessorSubclass::GetCapacity(
         BackingStoreClass::cast(backing_store));
   }
 
-  static MaybeObject* GetElement(
-      BackingStoreClass* backing_store,
-      uint32_t key) {
-    return backing_store->get(key);
-  }
-
-  virtual MaybeObject* GetElement(FixedArrayBase* backing_store,
-                                  uint32_t key) {
-    return ElementsAccessorSubclass::GetElement(
-        BackingStoreClass::cast(backing_store), key);
-  }
-
   static bool HasElementAtIndex(BackingStoreClass* backing_store,
-                                uint32_t index) {
+                                uint32_t index,
+                                JSObject* holder,
+                                Object* receiver) {
     uint32_t key =
         ElementsAccessorSubclass::GetKeyForIndex(backing_store, index);
-    MaybeObject* element = ElementsAccessorSubclass::GetElement(backing_store,
-                                                                key);
+    MaybeObject* element = ElementsAccessorSubclass::Get(backing_store,
+                                                         key,
+                                                         holder,
+                                                         receiver);
     return !element->IsTheHole();
   }
 
   virtual bool HasElementAtIndex(FixedArrayBase* backing_store,
-                                 uint32_t index) {
+                                 uint32_t index,
+                                 JSObject* holder,
+                                 Object* receiver) {
     return ElementsAccessorSubclass::HasElementAtIndex(
-        BackingStoreClass::cast(backing_store), index);
+        BackingStoreClass::cast(backing_store), index, holder, receiver);
   }
 
   static uint32_t GetKeyForIndex(BackingStoreClass* backing_store,
-                                         uint32_t index) {
+                                 uint32_t index) {
     return index;
   }
 
   virtual uint32_t GetKeyForIndex(FixedArrayBase* backing_store,
                                               uint32_t index) {
     return ElementsAccessorSubclass::GetKeyForIndex(
         BackingStoreClass::cast(backing_store), index);
   }
 
  private:
@@ skipping 70 matching lines @@
     int length = obj->IsJSArray()
         ? Smi::cast(JSArray::cast(obj)->length())->value()
         : FixedDoubleArray::cast(obj->elements())->length();
     if (key < static_cast<uint32_t>(length)) {
       FixedDoubleArray::cast(obj->elements())->set_the_hole(key);
     }
     return obj->GetHeap()->true_value();
   }
 
   static bool HasElementAtIndex(FixedDoubleArray* backing_store,
-                                uint32_t index) {
+                                uint32_t index,
+                                JSObject* holder,
+                                Object* receiver) {
     return !backing_store->is_the_hole(index);
   }
 };
 
 
 // Super class for all external element arrays.
 template<typename ExternalElementsAccessorSubclass,
          typename ExternalArray>
 class ExternalElementsAccessor
     : public ElementsAccessorBase<ExternalElementsAccessorSubclass,
                                   ExternalArray> {
  protected:
-  virtual MaybeObject* GetWithReceiver(JSObject* obj,
-                                       Object* receiver,
-                                       uint32_t key) {
-    ExternalArray* backing_store = ExternalArray::cast(obj->elements());
+  friend class ElementsAccessorBase<ExternalElementsAccessorSubclass,
+                                    ExternalArray>;
+
+  static MaybeObject* Get(ExternalArray* backing_store,
+                          uint32_t key,
+                          JSObject* obj,
+                          Object* receiver) {
     if (key < ExternalElementsAccessorSubclass::GetCapacity(backing_store)) {
       return backing_store->get(key);
     } else {
-      return obj->GetHeap()->undefined_value();
+      return backing_store->GetHeap()->undefined_value();
     }
   }
 
   virtual MaybeObject* Delete(JSObject* obj,
                               uint32_t key,
                               JSReceiver::DeleteMode mode) {
     // External arrays always ignore deletes.
     return obj->GetHeap()->true_value();
   }
 };
@@ skipping 50 matching lines @@
 class PixelElementsAccessor
     : public ExternalElementsAccessor<PixelElementsAccessor,
                                       ExternalPixelArray> {
 };
 
 
 class DictionaryElementsAccessor
     : public ElementsAccessorBase<DictionaryElementsAccessor,
                                   NumberDictionary> {
  public:
-  static MaybeObject* GetNumberDictionaryElement(
-      JSObject* obj,
-      Object* receiver,
-      NumberDictionary* backing_store,
-      uint32_t key) {
-    int entry = backing_store->FindEntry(key);
-    if (entry != NumberDictionary::kNotFound) {
-      Object* element = backing_store->ValueAt(entry);
-      PropertyDetails details = backing_store->DetailsAt(entry);
-      if (details.type() == CALLBACKS) {
-        return obj->GetElementWithCallback(receiver,
-                                           element,
-                                           key,
-                                           obj);
-      } else {
-        return element;
-      }
-    }
-    return obj->GetHeap()->the_hole_value();
-  }
-
   static MaybeObject* DeleteCommon(JSObject* obj,
                                    uint32_t key,
                                    JSReceiver::DeleteMode mode) {
     Isolate* isolate = obj->GetIsolate();
     Heap* heap = isolate->heap();
     FixedArray* backing_store = FixedArray::cast(obj->elements());
     bool is_arguments =
         (obj->GetElementsKind() == JSObject::NON_STRICT_ARGUMENTS_ELEMENTS);
     if (is_arguments) {
       backing_store = FixedArray::cast(backing_store->get(1));
@@ skipping 34 matching lines @@
  protected:
   friend class ElementsAccessorBase<DictionaryElementsAccessor,
                                     NumberDictionary>;
 
   virtual MaybeObject* Delete(JSObject* obj,
                               uint32_t key,
                               JSReceiver::DeleteMode mode) {
     return DeleteCommon(obj, key, mode);
   }
 
-  virtual MaybeObject* GetWithReceiver(JSObject* obj,
-                                       Object* receiver,
-                                       uint32_t key) {
-    return GetNumberDictionaryElement(obj,
-                                      receiver,
-                                      obj->element_dictionary(),
-                                      key);
+  static MaybeObject* Get(NumberDictionary* backing_store,
+                          uint32_t key,
+                          JSObject* obj,
+                          Object* receiver) {
+    int entry = backing_store->FindEntry(key);
+    if (entry != NumberDictionary::kNotFound) {
+      Object* element = backing_store->ValueAt(entry);
+      PropertyDetails details = backing_store->DetailsAt(entry);
+      if (details.type() == CALLBACKS) {
+        return obj->GetElementWithCallback(receiver,
+                                           element,
+                                           key,
+                                           obj);
+      } else {
+        return element;
+      }
+    }
+    return obj->GetHeap()->the_hole_value();
   }
 
   static uint32_t GetKeyForIndex(NumberDictionary* dict,
                                  uint32_t index) {
     Object* key = dict->KeyAt(index);
     return Smi::cast(key)->value();
   }
-
-  static MaybeObject* GetElement(NumberDictionary* dict,
-                                 int key) {
-    int entry = dict->FindEntry(key);
-    if (entry != NumberDictionary::kNotFound) {
-      return dict->ValueAt(entry);
-    } else {
-      return dict->GetHeap()->the_hole_value();
-    }
-  }
 };
 
 
 class NonStrictArgumentsElementsAccessor
     : public ElementsAccessorBase<NonStrictArgumentsElementsAccessor,
                                   FixedArray> {
  protected:
   friend class ElementsAccessorBase<NonStrictArgumentsElementsAccessor,
                                     FixedArray>;
 
-  virtual MaybeObject* GetWithReceiver(JSObject* obj,
-                                       Object* receiver,
-                                       uint32_t key) {
-    FixedArray* parameter_map = FixedArray::cast(obj->elements());
+  static MaybeObject* Get(FixedArray* parameter_map,
+                          uint32_t key,
+                          JSObject* obj,
+                          Object* receiver) {
     Object* probe = GetParameterMapArg(parameter_map, key);
     if (!probe->IsTheHole()) {
       Context* context = Context::cast(parameter_map->get(0));
       int context_index = Smi::cast(probe)->value();
       ASSERT(!context->get(context_index)->IsTheHole());
       return context->get(context_index);
     } else {
       // Object is not mapped, defer to the arguments.
       FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
-      if (arguments->IsDictionary()) {
-        return DictionaryElementsAccessor::GetNumberDictionaryElement(
-            obj,
-            receiver,
-            NumberDictionary::cast(arguments),
-            key);
-      } else if (key < static_cast<uint32_t>(arguments->length())) {
-        return arguments->get(key);
-      }
+      return ElementsAccessor::ForArray(arguments)->Get(arguments,
+                                                        key,
+                                                        obj,
+                                                        receiver);
     }
-    return obj->GetHeap()->the_hole_value();
   }
 
   virtual MaybeObject* Delete(JSObject* obj,
                               uint32_t key
                               ,
                               JSReceiver::DeleteMode mode) {
     FixedArray* parameter_map = FixedArray::cast(obj->elements());
     Object* probe = GetParameterMapArg(parameter_map, key);
     if (!probe->IsTheHole()) {
       // TODO(kmillikin): We could check if this was the last aliased
@@ skipping 16 matching lines @@
     return Max(static_cast<uint32_t>(parameter_map->length() - 2),
                ForArray(arguments)->GetCapacity(arguments));
   }
 
   static uint32_t GetKeyForIndex(FixedArray* dict,
                                  uint32_t index) {
     return index;
   }
 
   static bool HasElementAtIndex(FixedArray* parameter_map,
-                                uint32_t index) {
+                                uint32_t index,
+                                JSObject* holder,
+                                Object* receiver) {
     Object* probe = GetParameterMapArg(parameter_map, index);
     if (!probe->IsTheHole()) {
       return true;
     } else {
       FixedArrayBase* arguments = FixedArrayBase::cast(parameter_map->get(1));
       ElementsAccessor* accessor = ElementsAccessor::ForArray(arguments);
-      return !accessor->GetElement(arguments, index)->IsTheHole();
-    }
-  }
-
-  static MaybeObject* GetElement(FixedArray* parameter_map,
-                                 uint32_t key) {
-    Object* probe = GetParameterMapArg(parameter_map, key);
-    if (!probe->IsTheHole()) {
-      Context* context = Context::cast(parameter_map->get(0));
-      int context_index = Smi::cast(probe)->value();
-      ASSERT(!context->get(context_index)->IsTheHole());
-      return context->get(context_index);
-    } else {
-      FixedArrayBase* arguments = FixedArrayBase::cast(parameter_map->get(1));
-      return ForArray(arguments)->GetElement(arguments, key);
+      return !accessor->Get(arguments, index, holder, receiver)->IsTheHole();
     }
   }
 
  private:
-
   static Object* GetParameterMapArg(FixedArray* parameter_map,
                                     uint32_t key) {
     uint32_t length = parameter_map->length();
     return key < (length - 2 )
         ? parameter_map->get(key + 2)
         : parameter_map->GetHeap()->the_hole_value();
   }
 };
 
 
@@ skipping 62 matching lines @@
     &element_accessors.float_elements_handler,
     &element_accessors.double_elements_handler,
     &element_accessors.pixel_elements_handler
   };
 
   elements_accessors_ = accessor_array;
 }
 
 
 } }  // namespace v8::internal