[heap] delete Heap::LeftTrimFixedAray

src/heap/heap.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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 3047 matching lines @@
         reinterpret_cast<Map*>(root(kFreeSpaceMapRootIndex)));
     FreeSpace::cast(filler)->nobarrier_set_size(size);
   }
   // At this point, we may be deserializing the heap from a snapshot, and
   // none of the maps have been created yet and are NULL.
   DCHECK((filler->map() == NULL && !deserialization_complete_) ||
          filler->map()->IsMap());
 }
 
 
-bool Heap::CanMoveObjectStart(HeapObject* object) {
-  if (!FLAG_move_object_start) return false;
-
-  Address address = object->address();
-
-  if (lo_space()->Contains(object)) return false;
-
-  Page* page = Page::FromAddress(address);
-  // We can move the object start if:
-  // (1) the object is not in old space,
-  // (2) the page of the object was already swept,
-  // (3) the page was already concurrently swept. This case is an optimization
-  // for concurrent sweeping. The WasSwept predicate for concurrently swept
-  // pages is set after sweeping all pages.
-  return !InOldSpace(address) || page->WasSwept() || page->SweepingCompleted();
-}
-
-
 void Heap::AdjustLiveBytes(HeapObject* object, int by, InvocationMode mode) {
   if (incremental_marking()->IsMarking() &&
       Marking::IsBlack(Marking::MarkBitFrom(object->address()))) {
     if (mode == SEQUENTIAL_TO_SWEEPER) {
       MemoryChunk::IncrementLiveBytesFromGC(object, by);
     } else {
       MemoryChunk::IncrementLiveBytesFromMutator(object, by);
     }
   }
 }
 
 
-FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
-                                         int elements_to_trim) {
-  DCHECK(!object->IsFixedTypedArrayBase());
-  const int element_size = object->IsFixedArray() ? kPointerSize : kDoubleSize;
-  const int bytes_to_trim = elements_to_trim * element_size;
-  Map* map = object->map();
-
-  // For now this trick is only applied to objects in new and paged space.
-  // In large object space the object's start must coincide with chunk
-  // and thus the trick is just not applicable.
-  DCHECK(!lo_space()->Contains(object));
-  DCHECK(object->map() != fixed_cow_array_map());
-
-  STATIC_ASSERT(FixedArrayBase::kMapOffset == 0);
-  STATIC_ASSERT(FixedArrayBase::kLengthOffset == kPointerSize);
-  STATIC_ASSERT(FixedArrayBase::kHeaderSize == 2 * kPointerSize);
-
-  const int len = object->length();
-  DCHECK(elements_to_trim <= len);
-
-  // Calculate location of new array start.
-  Address new_start = object->address() + bytes_to_trim;
-
-  // Technically in new space this write might be omitted (except for
-  // debug mode which iterates through the heap), but to play safer
-  // we still do it.
-  CreateFillerObjectAt(object->address(), bytes_to_trim);
-
-  // Initialize header of the trimmed array. Since left trimming is only
-  // performed on pages which are not concurrently swept creating a filler
-  // object does not require synchronization.
-  DCHECK(CanMoveObjectStart(object));
-  Object** former_start = HeapObject::RawField(object, 0);
-  int new_start_index = elements_to_trim * (element_size / kPointerSize);
-  former_start[new_start_index] = map;
-  former_start[new_start_index + 1] = Smi::FromInt(len - elements_to_trim);
-  FixedArrayBase* new_object =
-      FixedArrayBase::cast(HeapObject::FromAddress(new_start));
-
-  // Maintain consistency of live bytes during incremental marking
-  Marking::TransferMark(this, object->address(), new_start);
-  AdjustLiveBytes(new_object, -bytes_to_trim, Heap::CONCURRENT_TO_SWEEPER);
-
-  // Notify the heap profiler of change in object layout.
-  OnMoveEvent(new_object, object, new_object->Size());
-  return new_object;
-}
-
-
 // Force instantiation of templatized method.
 template void Heap::RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(
     FixedArrayBase*, int);
 template void Heap::RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(
     FixedArrayBase*, int);
 
 
 template<Heap::InvocationMode mode>
 void Heap::RightTrimFixedArray(FixedArrayBase* object, int elements_to_trim) {
   const int len = object->length();
@@ skipping 3004 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8