Version 4.9.385.8 (cherry-pick)

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 17168 matching lines @@
 
 template<typename Derived, typename Shape, typename Key>
 Handle<Derived> HashTable<Derived, Shape, Key>::EnsureCapacity(
     Handle<Derived> table,
     int n,
     Key key,
     PretenureFlag pretenure) {
   Isolate* isolate = table->GetIsolate();
   int capacity = table->Capacity();
   int nof = table->NumberOfElements() + n;
-  int nod = table->NumberOfDeletedElements();
-  // Return if:
-  //   50% is still free after adding n elements and
-  //   at most 50% of the free elements are deleted elements.
-  if (nod <= (capacity - nof) >> 1) {
-    int needed_free = nof >> 1;
-    if (nof + needed_free <= capacity) return table;
-  }
+
+  if (table->HasSufficientCapacity(n)) return table;
 
   const int kMinCapacityForPretenure = 256;
   bool should_pretenure = pretenure == TENURED ||
       ((capacity > kMinCapacityForPretenure) &&
           !isolate->heap()->InNewSpace(*table));
   Handle<Derived> new_table = HashTable::New(
       isolate,
       nof * 2,
       USE_DEFAULT_MINIMUM_CAPACITY,
       should_pretenure ? TENURED : NOT_TENURED);
 
   table->Rehash(new_table, key);
   return new_table;
 }
 
 
+template <typename Derived, typename Shape, typename Key>
+bool HashTable<Derived, Shape, Key>::HasSufficientCapacity(int n) {
+  int capacity = Capacity();
+  int nof = NumberOfElements() + n;
+  int nod = NumberOfDeletedElements();
+  // Return true if:
+  //   50% is still free after adding n elements and
+  //   at most 50% of the free elements are deleted elements.
+  if (nod <= (capacity - nof) >> 1) {
+    int needed_free = nof >> 1;
+    if (nof + needed_free <= capacity) return true;
+  }
+  return false;
+}
+
+
 template<typename Derived, typename Shape, typename Key>
 Handle<Derived> HashTable<Derived, Shape, Key>::Shrink(Handle<Derived> table,
                                                        Key key) {
   int capacity = table->Capacity();
   int nof = table->NumberOfElements();
 
   // Shrink to fit the number of elements if only a quarter of the
   // capacity is filled with elements.
   if (nof > (capacity >> 2)) return table;
   // Allocate a new dictionary with room for at least the current
@@ skipping 146 matching lines @@
         PropertyDetails);
 
 template Handle<SeededNumberDictionary>
 Dictionary<SeededNumberDictionary, SeededNumberDictionaryShape, uint32_t>::
     EnsureCapacity(Handle<SeededNumberDictionary>, int, uint32_t);
 
 template Handle<UnseededNumberDictionary>
 Dictionary<UnseededNumberDictionary, UnseededNumberDictionaryShape, uint32_t>::
     EnsureCapacity(Handle<UnseededNumberDictionary>, int, uint32_t);
 
+template void Dictionary<NameDictionary, NameDictionaryShape,
+                         Handle<Name> >::SetRequiresCopyOnCapacityChange();
+
 template Handle<NameDictionary>
 Dictionary<NameDictionary, NameDictionaryShape, Handle<Name> >::
     EnsureCapacity(Handle<NameDictionary>, int, Handle<Name>);
 
 template bool Dictionary<SeededNumberDictionary, SeededNumberDictionaryShape,
                          uint32_t>::HasComplexElements();
 
 template int HashTable<SeededNumberDictionary, SeededNumberDictionaryShape,
                        uint32_t>::FindEntry(uint32_t);
 
@@ skipping 708 matching lines @@
     PropertyDetails new_details = details.set_index(enum_index);
     dictionary->DetailsAtPut(index, new_details);
   }
 
   // Set the next enumeration index.
   dictionary->SetNextEnumerationIndex(PropertyDetails::kInitialIndex+length);
   return iteration_order;
 }
 
 
-template<typename Derived, typename Shape, typename Key>
+template <typename Derived, typename Shape, typename Key>
+void Dictionary<Derived, Shape, Key>::SetRequiresCopyOnCapacityChange() {
+  DCHECK_EQ(0, DerivedHashTable::NumberOfElements());
+  DCHECK_EQ(0, DerivedHashTable::NumberOfDeletedElements());
+  // Make sure that HashTable::EnsureCapacity will create a copy.
+  DerivedHashTable::SetNumberOfDeletedElements(DerivedHashTable::Capacity());
+  DCHECK(!DerivedHashTable::HasSufficientCapacity(1));
+}
+
+
+template <typename Derived, typename Shape, typename Key>
 Handle<Derived> Dictionary<Derived, Shape, Key>::EnsureCapacity(
     Handle<Derived> dictionary, int n, Key key) {
   // Check whether there are enough enumeration indices to add n elements.
   if (Shape::kIsEnumerable &&
       !PropertyDetails::IsValidIndex(dictionary->NextEnumerationIndex() + n)) {
     // If not, we generate new indices for the properties.
     GenerateNewEnumerationIndices(dictionary);
   }
   return DerivedHashTable::EnsureCapacity(dictionary, n, key);
 }
@@ skipping 1551 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8