Move left and right trimming of FixedArray into Heap.

src/elements.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/arguments.h"
 #include "src/conversions.h"
 #include "src/elements.h"
 #include "src/objects.h"
@@ skipping 855 matching lines @@
     return ElementsAccessorSubclass::GetKeyForIndexImpl(backing_store, index);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ElementsAccessorBase);
 };
 
 
 // Super class for all fast element arrays.
 template<typename FastElementsAccessorSubclass,
-         typename KindTraits,
-         int ElementSize>
+         typename KindTraits>
 class FastElementsAccessor
     : public ElementsAccessorBase<FastElementsAccessorSubclass, KindTraits> {
  public:
   explicit FastElementsAccessor(const char* name)
       : ElementsAccessorBase<FastElementsAccessorSubclass,
                              KindTraits>(name) {}
  protected:
   friend class ElementsAccessorBase<FastElementsAccessorSubclass, KindTraits>;
   friend class SloppyArgumentsElementsAccessor;
 
@@ skipping 21 matching lines @@
     // Check whether the backing store should be shrunk.
     if (length <= old_capacity) {
       if (array->HasFastSmiOrObjectElements()) {
         backing_store = JSObject::EnsureWritableFastElements(array);
       }
       if (2 * length <= old_capacity) {
         // If more than half the elements won't be used, trim the array.
         if (length == 0) {
           array->initialize_elements();
         } else {
-          int filler_size = (old_capacity - length) * ElementSize;
-          Address filler_start = backing_store->address() +
-              BackingStore::OffsetOfElementAt(length);
-          array->GetHeap()->CreateFillerObjectAt(filler_start, filler_size);
-
-          // We are storing the new length using release store after creating a
-          // filler for the left-over space to avoid races with the sweeper
-          // thread.
-          backing_store->synchronized_set_length(length);
+          isolate->heap()->RightTrimFixedArray<Heap::FROM_MUTATOR>(
+              *backing_store, old_capacity - length);
         }
       } else {
         // Otherwise, fill the unused tail with holes.
         int old_length = FastD2IChecked(array->length()->Number());
         for (int i = length; i < old_length; i++) {
           Handle<BackingStore>::cast(backing_store)->set_the_hole(i);
         }
       }
       return length_object;
     }
@@ skipping 133 matching lines @@
     default:
       UNREACHABLE();
   }
   return FAST_HOLEY_ELEMENTS;
 }
 
 
 template<typename FastElementsAccessorSubclass,
          typename KindTraits>
 class FastSmiOrObjectElementsAccessor
-    : public FastElementsAccessor<FastElementsAccessorSubclass,
-                                  KindTraits,
-                                  kPointerSize> {
+    : public FastElementsAccessor<FastElementsAccessorSubclass, KindTraits> {
  public:
   explicit FastSmiOrObjectElementsAccessor(const char* name)
       : FastElementsAccessor<FastElementsAccessorSubclass,
-                             KindTraits,
-                             kPointerSize>(name) {}
+                             KindTraits>(name) {}
 
   static void CopyElementsImpl(Handle<FixedArrayBase> from,
                                uint32_t from_start,
                                Handle<FixedArrayBase> to,
                                ElementsKind from_kind,
                                uint32_t to_start,
                                int packed_size,
                                int copy_size) {
     ElementsKind to_kind = KindTraits::Kind;
     switch (from_kind) {
@@ skipping 93 matching lines @@
   explicit FastHoleyObjectElementsAccessor(const char* name)
       : FastSmiOrObjectElementsAccessor<
           FastHoleyObjectElementsAccessor,
           ElementsKindTraits<FAST_HOLEY_ELEMENTS> >(name) {}
 };
 
 
 template<typename FastElementsAccessorSubclass,
          typename KindTraits>
 class FastDoubleElementsAccessor
-    : public FastElementsAccessor<FastElementsAccessorSubclass,
-                                  KindTraits,
-                                  kDoubleSize> {
+    : public FastElementsAccessor<FastElementsAccessorSubclass, KindTraits> {
  public:
   explicit FastDoubleElementsAccessor(const char* name)
       : FastElementsAccessor<FastElementsAccessorSubclass,
-                             KindTraits,
-                             kDoubleSize>(name) {}
+                             KindTraits>(name) {}
 
   static void SetFastElementsCapacityAndLength(Handle<JSObject> obj,
                                                uint32_t capacity,
                                                uint32_t length) {
     JSObject::SetFastDoubleElementsCapacityAndLength(obj, capacity, length);
   }
 
  protected:
   static void CopyElementsImpl(Handle<FixedArrayBase> from,
                                uint32_t from_start,
@@ skipping 754 matching lines @@
       UNREACHABLE();
       break;
   }
 
   array->set_elements(*elms);
   array->set_length(Smi::FromInt(number_of_elements));
   return array;
 }
 
 } }  // namespace v8::internal