[heap] Simplify clearing of normalized map caches.

src/heap/incremental-marking.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/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 135 matching lines @@
     heap->incremental_marking()->RestartIfNotMarking();
   }
 }
 
 class IncrementalMarkingMarkingVisitor
     : public StaticMarkingVisitor<IncrementalMarkingMarkingVisitor> {
  public:
   static void Initialize() {
     StaticMarkingVisitor<IncrementalMarkingMarkingVisitor>::Initialize();
     table_.Register(kVisitFixedArray, &VisitFixedArrayIncremental);
-    table_.Register(kVisitNativeContext, &VisitNativeContextIncremental);
   }
 
   static const int kProgressBarScanningChunk = 32 * 1024;
 
   static void VisitFixedArrayIncremental(Map* map, HeapObject* object) {
     MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
     if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
       DCHECK(!FLAG_use_marking_progress_bar ||
              chunk->owner()->identity() == LO_SPACE);
       Heap* heap = map->GetHeap();
@@ skipping 25 matching lines @@
           heap->mark_compact_collector()->UnshiftBlack(object);
         }
         heap->incremental_marking()->NotifyIncompleteScanOfObject(
             object_size - (start_offset - already_scanned_offset));
       }
     } else {
       FixedArrayVisitor::Visit(map, object);
     }
   }
 
-  static void VisitNativeContextIncremental(Map* map, HeapObject* object) {
-    Context* context = Context::cast(object);
-
-    // We will mark cache black with a separate pass when we finish marking.
-    // Note that GC can happen when the context is not fully initialized,
-    // so the cache can be undefined.
-    Object* cache = context->get(Context::NORMALIZED_MAP_CACHE_INDEX);
-    if (!cache->IsUndefined(map->GetIsolate())) {
-      if (cache->IsHeapObject()) {
-        HeapObject* heap_obj = HeapObject::cast(cache);
-        // Mark the object grey if it is white, do not enque it into the marking
-        // deque.
-        if (ObjectMarking::IsWhite(heap_obj)) {
-          ObjectMarking::WhiteToGrey(heap_obj);
-        }
-      }
-    }
-    VisitNativeContext(map, context);
-  }
-
   INLINE(static void VisitPointer(Heap* heap, HeapObject* object, Object** p)) {
     Object* target = *p;
     if (target->IsHeapObject()) {
       heap->mark_compact_collector()->RecordSlot(object, p, target);
       MarkObject(heap, target);
     }
   }
 
   INLINE(static void VisitPointers(Heap* heap, HeapObject* object,
                                    Object** start, Object** end)) {
@@ skipping 924 matching lines @@
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 
 }  // namespace internal
 }  // namespace v8