Move ClearNonLiveReferences and friends into the gc.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 4a9a09fc298641946119d764a7ea34cc6dd18e86..0ab325b45ba9d2bbf780760c4f0dbe7f7f39bbf4 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -9533,119 +9533,6 @@ void String::PrintOn(FILE* file) {
 }
 
 
-static void TrimEnumCache(Heap* heap, Map* map, DescriptorArray* descriptors) {
-  int live_enum = map->EnumLength();
-  if (live_enum == kInvalidEnumCacheSentinel) {
-    live_enum = map->NumberOfDescribedProperties(OWN_DESCRIPTORS, DONT_ENUM);
-  }
-  if (live_enum == 0) return descriptors->ClearEnumCache();
-
-  FixedArray* enum_cache = descriptors->GetEnumCache();
-
-  int to_trim = enum_cache->length() - live_enum;
-  if (to_trim <= 0) return;
-  heap->RightTrimFixedArray<Heap::FROM_GC>(
-      descriptors->GetEnumCache(), to_trim);
-
-  if (!descriptors->HasEnumIndicesCache()) return;
-  FixedArray* enum_indices_cache = descriptors->GetEnumIndicesCache();
-  heap->RightTrimFixedArray<Heap::FROM_GC>(enum_indices_cache, to_trim);
-}
-
-
-static void TrimDescriptorArray(Heap* heap,
-                                Map* map,
-                                DescriptorArray* descriptors,
-                                int number_of_own_descriptors) {
-  int number_of_descriptors = descriptors->number_of_descriptors_storage();
-  int to_trim = number_of_descriptors - number_of_own_descriptors;
-  if (to_trim == 0) return;
-
-  heap->RightTrimFixedArray<Heap::FROM_GC>(
-      descriptors, to_trim * DescriptorArray::kDescriptorSize);
-  descriptors->SetNumberOfDescriptors(number_of_own_descriptors);
-
-  if (descriptors->HasEnumCache()) TrimEnumCache(heap, map, descriptors);
-  descriptors->Sort();
-}
-
-
-// Clear a possible back pointer in case the transition leads to a dead map.
-// Return true in case a back pointer has been cleared and false otherwise.
-static bool ClearBackPointer(Heap* heap, Map* target) {
-  if (Marking::MarkBitFrom(target).Get()) return false;
-  target->SetBackPointer(heap->undefined_value(), SKIP_WRITE_BARRIER);
-  return true;
-}
-
-
-// TODO(mstarzinger): This method should be moved into MarkCompactCollector,
-// because it cannot be called from outside the GC and we already have methods
-// depending on the transitions layout in the GC anyways.
-void Map::ClearNonLiveTransitions(Heap* heap) {
-  // If there are no transitions to be cleared, return.
-  // TODO(verwaest) Should be an assert, otherwise back pointers are not
-  // properly cleared.
-  if (!HasTransitionArray()) return;
-
-  TransitionArray* t = transitions();
-  MarkCompactCollector* collector = heap->mark_compact_collector();
-
-  int transition_index = 0;
-
-  DescriptorArray* descriptors = instance_descriptors();
-  bool descriptors_owner_died = false;
-
-  // Compact all live descriptors to the left.
-  for (int i = 0; i < t->number_of_transitions(); ++i) {
-    Map* target = t->GetTarget(i);
-    if (ClearBackPointer(heap, target)) {
-      if (target->instance_descriptors() == descriptors) {
-        descriptors_owner_died = true;
-      }
-    } else {
-      if (i != transition_index) {
-        Name* key = t->GetKey(i);
-        t->SetKey(transition_index, key);
-        Object** key_slot = t->GetKeySlot(transition_index);
-        collector->RecordSlot(key_slot, key_slot, key);
-        // Target slots do not need to be recorded since maps are not compacted.
-        t->SetTarget(transition_index, t->GetTarget(i));
-      }
-      transition_index++;
-    }
-  }
-
-  // If there are no transitions to be cleared, return.
-  // TODO(verwaest) Should be an assert, otherwise back pointers are not
-  // properly cleared.
-  if (transition_index == t->number_of_transitions()) return;
-
-  int number_of_own_descriptors = NumberOfOwnDescriptors();
-
-  if (descriptors_owner_died) {
-    if (number_of_own_descriptors > 0) {
-      TrimDescriptorArray(heap, this, descriptors, number_of_own_descriptors);
-      DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors);
-      set_owns_descriptors(true);
-    } else {
-      DCHECK(descriptors == GetHeap()->empty_descriptor_array());
-    }
-  }
-
-  // Note that we never eliminate a transition array, though we might right-trim
-  // such that number_of_transitions() == 0. If this assumption changes,
-  // TransitionArray::CopyInsert() will need to deal with the case that a
-  // transition array disappeared during GC.
-  int trim = t->number_of_transitions() - transition_index;
-  if (trim > 0) {
-    heap->RightTrimFixedArray<Heap::FROM_GC>(t, t->IsSimpleTransition()
-        ? trim : trim * TransitionArray::kTransitionSize);
-  }
-  DCHECK(HasTransitionArray());
-}
-
-
 int Map::Hash() {
   // For performance reasons we only hash the 3 most variable fields of a map:
   // constructor, prototype and bit_field2.