[elements] move MoveElements to abstract superclass

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/elements.h"
 
 #include "src/arguments.h"
 #include "src/conversions.h"
 #include "src/factory.h"
 #include "src/isolate-inl.h"
@@ skipping 1585 matching lines @@
                                                       args, push_size, AT_END);
   }
 
   static uint32_t UnshiftImpl(Handle<JSArray> receiver,
                               Arguments* args, uint32_t unshift_size) {
     Handle<FixedArrayBase> backing_store(receiver->elements());
     return FastElementsAccessorSubclass::AddArguments(
         receiver, backing_store, args, unshift_size, AT_START);
   }
 
-  static void MoveElements(Isolate* isolate, Handle<JSArray> receiver,
-                           Handle<FixedArrayBase> backing_store, int dst_index,
-                           int src_index, int len, int hole_start,
-                           int hole_end) {
-    UNREACHABLE();
-  }
-
   static Handle<JSArray> SliceImpl(Handle<JSObject> receiver,
                                    uint32_t start, uint32_t end) {
     Isolate* isolate = receiver->GetIsolate();
     Handle<FixedArrayBase> backing_store(receiver->elements(), isolate);
     int result_len = end < start ? 0u : end - start;
     Handle<JSArray> result_array = isolate->factory()->NewJSArray(
         KindTraits::Kind, result_len, result_len);
     DisallowHeapAllocation no_gc;
     FastElementsAccessorSubclass::CopyElementsImpl(
         *backing_store, start, result_array->elements(), KindTraits::Kind, 0,
@@ skipping 70 matching lines @@
           FastElementsAccessorSubclass::GetImpl(object->elements(), index);
       if (get_entries) {
         value = MakeEntryPair(isolate, index, value);
       }
       values_or_entries->set(count++, *value);
     }
     *nof_items = count;
     return Just(true);
   }
 
+  static void MoveElements(Isolate* isolate, Handle<JSArray> receiver,
+                           Handle<FixedArrayBase> backing_store, int dst_index,
+                           int src_index, int len, int hole_start,
+                           int hole_end) {
+    Heap* heap = isolate->heap();
+    Handle<BackingStore> dst_elms = Handle<BackingStore>::cast(backing_store);
+    if (heap->CanMoveObjectStart(*dst_elms) && dst_index == 0) {
+      // Update all the copies of this backing_store handle.
+      *dst_elms.location() =
+          BackingStore::cast(heap->LeftTrimFixedArray(*dst_elms, src_index));
+      receiver->set_elements(*dst_elms);
+      // Adjust the hole offset as the array has been shrunk.
+      hole_end -= src_index;
+      DCHECK_LE(hole_start, backing_store->length());
+      DCHECK_LE(hole_end, backing_store->length());
+    } else if (len != 0) {
+      if (IsFastDoubleElementsKind(KindTraits::Kind)) {
+        MemMove(dst_elms->data_start() + dst_index,
+                dst_elms->data_start() + src_index, len * kDoubleSize);
+      } else {
+        DisallowHeapAllocation no_gc;
+        heap->MoveElements(FixedArray::cast(*dst_elms), dst_index, src_index,
+                           len);
+      }
+    }
+    if (hole_start != hole_end) {
+      dst_elms->FillWithHoles(hole_start, hole_end);
+    }
+  }
+
  private:
   // SpliceShrinkStep might modify the backing_store.
   static void SpliceShrinkStep(Isolate* isolate, Handle<JSArray> receiver,
                                Handle<FixedArrayBase> backing_store,
                                uint32_t start, uint32_t delete_count,
                                uint32_t add_count, uint32_t len,
                                uint32_t new_length) {
     const int move_left_count = len - delete_count - start;
     const int move_left_dst_index = start + add_count;
     FastElementsAccessorSubclass::MoveElements(
@@ skipping 138 matching lines @@
                              Object* value, WriteBarrierMode mode) {
     FixedArray::cast(backing_store)->set(entry, value, mode);
   }
 
   static Object* GetRaw(FixedArray* backing_store, uint32_t entry) {
     uint32_t index = FastElementsAccessorSubclass::GetIndexForEntryImpl(
         backing_store, entry);
     return backing_store->get(index);
   }
 
-  static void MoveElements(Isolate* isolate, Handle<JSArray> receiver,
-                           Handle<FixedArrayBase> backing_store, int dst_index,
-                           int src_index, int len, int hole_start,
-                           int hole_end) {
-    Heap* heap = isolate->heap();
-    Handle<FixedArray> dst_elms = Handle<FixedArray>::cast(backing_store);
-    if (heap->CanMoveObjectStart(*dst_elms) && dst_index == 0) {
-      // Update all the copies of this backing_store handle.
-      *dst_elms.location() =
-          FixedArray::cast(heap->LeftTrimFixedArray(*dst_elms, src_index));
-      receiver->set_elements(*dst_elms);
-      // Adjust the hole offset as the array has been shrunk.
-      hole_end -= src_index;
-      DCHECK_LE(hole_start, backing_store->length());
-      DCHECK_LE(hole_end, backing_store->length());
-    } else if (len != 0) {
-      DisallowHeapAllocation no_gc;
-      heap->MoveElements(*dst_elms, dst_index, src_index, len);
-    }
-    if (hole_start != hole_end) {
-      dst_elms->FillWithHoles(hole_start, hole_end);
-    }
-  }
 
   // NOTE: this method violates the handlified function signature convention:
   // raw pointer parameters in the function that allocates.
   // See ElementsAccessor::CopyElements() for details.
   // This method could actually allocate if copying from double elements to
   // object elements.
   static void CopyElementsImpl(FixedArrayBase* from, uint32_t from_start,
                                FixedArrayBase* to, ElementsKind from_kind,
                                uint32_t to_start, int packed_size,
                                int copy_size) {
@@ skipping 111 matching lines @@
   static inline void SetImpl(FixedArrayBase* backing_store, uint32_t entry,
                              Object* value) {
     FixedDoubleArray::cast(backing_store)->set(entry, value->Number());
   }
 
   static inline void SetImpl(FixedArrayBase* backing_store, uint32_t entry,
                              Object* value, WriteBarrierMode mode) {
     FixedDoubleArray::cast(backing_store)->set(entry, value->Number());
   }
 
-  static void MoveElements(Isolate* isolate, Handle<JSArray> receiver,
-                           Handle<FixedArrayBase> backing_store, int dst_index,
-                           int src_index, int len, int hole_start,
-                           int hole_end) {
-    Heap* heap = isolate->heap();
-    Handle<FixedDoubleArray> dst_elms =
-        Handle<FixedDoubleArray>::cast(backing_store);
-    if (heap->CanMoveObjectStart(*dst_elms) && dst_index == 0) {
-      // Update all the copies of this backing_store handle.
-      *dst_elms.location() = FixedDoubleArray::cast(
-          heap->LeftTrimFixedArray(*dst_elms, src_index));
-      receiver->set_elements(*dst_elms);
-      // Adjust the hole offset as the array has been shrunk.
-      hole_end -= src_index;
-      DCHECK_LE(hole_start, backing_store->length());
-      DCHECK_LE(hole_end, backing_store->length());
-    } else if (len != 0) {
-      MemMove(dst_elms->data_start() + dst_index,
-              dst_elms->data_start() + src_index, len * kDoubleSize);
-    }
-    if (hole_start != hole_end) {
-      dst_elms->FillWithHoles(hole_start, hole_end);
-    }
-  }
-
   static void CopyElementsImpl(FixedArrayBase* from, uint32_t from_start,
                                FixedArrayBase* to, ElementsKind from_kind,
                                uint32_t to_start, int packed_size,
                                int copy_size) {
     DisallowHeapAllocation no_allocation;
     switch (from_kind) {
       case FAST_SMI_ELEMENTS:
         CopyPackedSmiToDoubleElements(from, from_start, to, to_start,
                                       packed_size, copy_size);
         break;
@@ skipping 979 matching lines @@
     insertion_index += len;
   }
 
   DCHECK_EQ(insertion_index, result_len);
   return result_array;
 }
 
 ElementsAccessor** ElementsAccessor::elements_accessors_ = NULL;
 }  // namespace internal
 }  // namespace v8