MarkBit cleanup: They have to be accessed through Marking accessors.

src/heap/spaces.cc

 // Copyright 2011 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/v8.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
@@ skipping 2953 matching lines @@
 
 void LargeObjectSpace::FreeUnmarkedObjects() {
   LargePage* previous = NULL;
   LargePage* current = first_page_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
     // Can this large page contain pointers to non-trivial objects.  No other
     // pointer object is this big.
     bool is_pointer_object = object->IsFixedArray();
     MarkBit mark_bit = Marking::MarkBitFrom(object);
-    if (mark_bit.Get()) {
-      mark_bit.Clear();
+    if (Marking::IsBlackOrGrey(mark_bit)) {
+      Marking::BlackToWhite(mark_bit);
       Page::FromAddress(object->address())->ResetProgressBar();
       Page::FromAddress(object->address())->ResetLiveBytes();
       previous = current;
       current = current->next_page();
     } else {
       LargePage* page = current;
       // Cut the chunk out from the chunk list.
       current = current->next_page();
       if (previous == NULL) {
         first_page_ = current;
@@ skipping 134 matching lines @@
 
 void Page::Print() {
   // Make a best-effort to print the objects in the page.
   PrintF("Page@%p in %s\n", this->address(),
          AllocationSpaceName(this->owner()->identity()));
   printf(" --------------------------------------\n");
   HeapObjectIterator objects(this, heap()->GcSafeSizeOfOldObjectFunction());
   unsigned mark_size = 0;
   for (HeapObject* object = objects.Next(); object != NULL;
        object = objects.Next()) {
-    bool is_marked = Marking::MarkBitFrom(object).Get();
+    bool is_marked = Marking::IsBlackOrGrey(Marking::MarkBitFrom(object));
     PrintF(" %c ", (is_marked ? '!' : ' '));  // Indent a little.
     if (is_marked) {
       mark_size += heap()->GcSafeSizeOfOldObjectFunction()(object);
     }
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }
 }  // namespace v8::internal