Remove LeftTrimFixedArray

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 3469 matching lines @@
       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 3025 matching lines @@
     *object_sub_type = "CODE_AGE/" #name;                              \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8