Refactor UnionOfKeys into ElementsAccessor

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/7529046

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8870 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/elements.cc

@@ -37,6 +37,20 @@ namespace internal {
 ElementsAccessor** ElementsAccessor::elements_accessors_;
 
 
+bool HasKey(FixedArray* array, Object* key) {
+  int len0 = array->length();
+  for (int i = 0; i < len0; i++) {
+    Object* element = array->get(i);
+    if (element->IsSmi() && element == key) return true;
+    if (element->IsString() &&
+        key->IsString() && String::cast(element)->Equals(String::cast(key))) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 // Base class for element handler implementations. Contains the
 // the common logic for objects with different ElementsKinds.
 // Subclasses must specialize method for which the element
@@ -73,6 +87,78 @@ class ElementsAccessorBase : public ElementsAccessor {
                               uint32_t index,
                               JSReceiver::DeleteMode mode) = 0;
 
+  virtual MaybeObject* AddJSArrayKeysToFixedArray(JSArray* other,
+                                                  FixedArray* keys) {
+    int len0 = keys->length();
+#ifdef DEBUG
+    if (FLAG_enable_slow_asserts) {
+      for (int i = 0; i < len0; i++) {
+        ASSERT(keys->get(i)->IsString() || keys->get(i)->IsNumber());
+      }
+    }
+#endif
+    int len1 = ElementsAccessorSubclass::GetCapacity(other);
+
+    // Optimize if 'other' is empty.
+    // We cannot optimize if 'this' is empty, as other may have holes
+    // or non keys.
+    if (len1 == 0) return keys;
+
+    // Compute how many elements are not in other.
+    int extra = 0;
+    for (int y = 0; y < len1; y++) {
+      Object* value;
+      MaybeObject* maybe_value =
+          ElementsAccessorSubclass::GetElementAtCapacityIndex(other, y);
+      if (!maybe_value->ToObject(&value)) return maybe_value;
+      if (!value->IsTheHole() && !HasKey(keys, value)) extra++;
+    }
+
+    if (extra == 0) return keys;
+
+    // Allocate the result
+    FixedArray* result;
+    MaybeObject* maybe_obj =
+        other->GetHeap()->AllocateFixedArray(len0 + extra);
+    if (!maybe_obj->To<FixedArray>(&result)) return maybe_obj;
+
+    // Fill in the content
+    {
+      AssertNoAllocation no_gc;
+      WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
+      for (int i = 0; i < len0; i++) {
+        Object* e = keys->get(i);
+        ASSERT(e->IsString() || e->IsNumber());
+        result->set(i, e, mode);
+      }
+    }
+    // Fill in the extra keys.
+    int index = 0;
+    for (int y = 0; y < len1; y++) {
+      MaybeObject* maybe_value =
+          ElementsAccessorSubclass::GetElementAtCapacityIndex(other, y);
+      Object* value;
+      if (!maybe_value->ToObject(&value)) return maybe_value;
+      if (!value->IsTheHole() && !HasKey(keys, value)) {
+        ASSERT(value->IsString() || value->IsNumber());
+        result->set(len0 + index, value);
+        index++;
+      }
+    }
+    ASSERT(extra == index);
+    return result;
+  }
+
+  static uint32_t GetCapacity(JSObject* obj) {
+    return ElementsAccessorSubclass::GetBackingStore(obj)->length();
+  }
+
+  static MaybeObject* GetElementAtCapacityIndex(JSObject* obj, int index) {
+    BackingStoreClass* backing_store =
+        ElementsAccessorSubclass::GetBackingStore(obj);
+    return backing_store->get(index);
+  }
+
  protected:
   static BackingStoreClass* GetBackingStore(JSObject* obj) {
     return BackingStoreClass::cast(obj->elements());
@@ -325,6 +411,19 @@ class DictionaryElementsAccessor
                                       obj->element_dictionary(),
                                       index);
   }
+
+  static uint32_t GetCapacity(JSObject* obj) {
+    return obj->element_dictionary()->Capacity();
+  }
+
+  static MaybeObject* GetElementAtCapacityIndex(JSObject* obj, int index) {
+    NumberDictionary* dict = obj->element_dictionary();
+    if (dict->IsKey(dict->KeyAt(index))) {
+      return dict->ValueAt(index);
+    } else {
+      return obj->GetHeap()->the_hole_value();
+    }
+  }
 };
 
 
@@ -382,6 +481,18 @@ class NonStrictArgumentsElementsAccessor
     }
     return obj->GetHeap()->true_value();
   }
+
+  static uint32_t GetCapacity(JSObject* obj) {
+    // TODO(danno): Return max of parameter map length or backing store
+    // capacity.
+    return 0;
+  }
+
+  static MaybeObject* GetElementAtCapacityIndex(JSObject* obj, int index) {
+    // TODO(danno): Return either value from parameter map of backing
+    // store value at index.
+    return obj->GetHeap()->the_hole_value();
+  }
 };
 
 

src/elements.h

@@ -47,6 +47,9 @@ class ElementsAccessor {
                               uint32_t index,
                               JSReceiver::DeleteMode mode) = 0;
 
+  virtual MaybeObject* AddJSArrayKeysToFixedArray(JSArray* other,
+                                                  FixedArray* keys) = 0;
+
   // Returns a shared ElementsAccessor for the specified ElementsKind.
   static ElementsAccessor* ForKind(JSObject::ElementsKind elements_kind) {
     ASSERT(elements_kind < JSObject::kElementsKindCount);

src/objects.cc

@@ -4637,51 +4637,7 @@ MaybeObject* PolymorphicCodeCacheHashTable::Put(MapList* maps,
 
 
 MaybeObject* FixedArray::AddKeysFromJSArray(JSArray* array) {
-  ASSERT(!array->HasExternalArrayElements());
-  switch (array->GetElementsKind()) {
-    case JSObject::FAST_ELEMENTS:
-      return UnionOfKeys(FixedArray::cast(array->elements()));
-    case JSObject::FAST_DOUBLE_ELEMENTS:
-      return UnionOfDoubleKeys(FixedDoubleArray::cast(array->elements()));
-      break;
-    case JSObject::DICTIONARY_ELEMENTS: {
-      NumberDictionary* dict = array->element_dictionary();
-      int size = dict->NumberOfElements();
-
-      // Allocate a temporary fixed array.
-      Object* object;
-      { MaybeObject* maybe_object = GetHeap()->AllocateFixedArray(size);
-        if (!maybe_object->ToObject(&object)) return maybe_object;
-      }
-      FixedArray* key_array = FixedArray::cast(object);
-
-      int capacity = dict->Capacity();
-      int pos = 0;
-      // Copy the elements from the JSArray to the temporary fixed array.
-      for (int i = 0; i < capacity; i++) {
-        if (dict->IsKey(dict->KeyAt(i))) {
-          key_array->set(pos++, dict->ValueAt(i));
-        }
-      }
-      // Compute the union of this and the temporary fixed array.
-      return UnionOfKeys(key_array);
-    }
-    case JSObject::NON_STRICT_ARGUMENTS_ELEMENTS:
-      UNIMPLEMENTED();
-      break;
-    case JSObject::EXTERNAL_BYTE_ELEMENTS:
-    case JSObject::EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
-    case JSObject::EXTERNAL_SHORT_ELEMENTS:
-    case JSObject::EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
-    case JSObject::EXTERNAL_INT_ELEMENTS:
-    case JSObject::EXTERNAL_UNSIGNED_INT_ELEMENTS:
-    case JSObject::EXTERNAL_FLOAT_ELEMENTS:
-    case JSObject::EXTERNAL_DOUBLE_ELEMENTS:
-    case JSObject::EXTERNAL_PIXEL_ELEMENTS:
-      break;
-  }
-  UNREACHABLE();
-  return GetHeap()->null_value();  // Failure case needs to "return" a value.
+  return array->GetElementsAccessor()->AddJSArrayKeysToFixedArray(array, this);
 }
 
 
@@ -4739,69 +4695,6 @@ MaybeObject* FixedArray::UnionOfKeys(FixedArray* other) {
 }
 
 
-MaybeObject* FixedArray::UnionOfDoubleKeys(FixedDoubleArray* other) {
-  int len0 = length();
-#ifdef DEBUG
-  if (FLAG_enable_slow_asserts) {
-    for (int i = 0; i < len0; i++) {
-      ASSERT(get(i)->IsString() || get(i)->IsNumber());
-    }
-  }
-#endif
-  int len1 = other->length();
-  // Optimize if 'other' is empty.
-  // We cannot optimize if 'this' is empty, as other may have holes
-  // or non keys.
-  if (len1 == 0) return this;
-
-  // Compute how many elements are not in this.
-  int extra = 0;
-  Heap* heap = GetHeap();
-  Object* obj;
-  for (int y = 0; y < len1; y++) {
-    if (!other->is_the_hole(y)) {
-      MaybeObject* maybe_obj = heap->NumberFromDouble(other->get_scalar(y));
-      if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-      if (!HasKey(this, obj)) extra++;
-    }
-  }
-
-  if (extra == 0) return this;
-
-  // Allocate the result
-  { MaybeObject* maybe_obj = GetHeap()->AllocateFixedArray(len0 + extra);
-    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-  }
-  // Fill in the content
-  FixedArray* result = FixedArray::cast(obj);
-  {
-    // Limit the scope of the AssertNoAllocation
-    AssertNoAllocation no_gc;
-    WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
-    for (int i = 0; i < len0; i++) {
-      Object* e = get(i);
-      ASSERT(e->IsString() || e->IsNumber());
-      result->set(i, e, mode);
-    }
-  }
-
-  // Fill in the extra keys.
-  int index = 0;
-  for (int y = 0; y < len1; y++) {
-    if (!other->is_the_hole(y)) {
-      MaybeObject* maybe_obj = heap->NumberFromDouble(other->get_scalar(y));
-      if (!maybe_obj->ToObject(&obj)) return maybe_obj;
-      if (!HasKey(this, obj)) {
-        result->set(len0 + index, obj);
-        index++;
-      }
-    }
-  }
-  ASSERT(extra == index);
-  return result;
-}
-
-
 MaybeObject* FixedArray::CopySize(int new_length) {
   Heap* heap = GetHeap();
   if (new_length == 0) return heap->empty_fixed_array();

src/objects.h

@@ -2128,10 +2128,6 @@ class FixedArray: public FixedArrayBase {
   // Compute the union of this and other.
   MUST_USE_RESULT MaybeObject* UnionOfKeys(FixedArray* other);
 
-  // Compute the union of this and other.
-  MUST_USE_RESULT MaybeObject* UnionOfDoubleKeys(
-      FixedDoubleArray* other);
-
   // Copy a sub array from the receiver to dest.
   void CopyTo(int pos, FixedArray* dest, int dest_pos, int len);