[heap] Reland "Make non-atomic markbit operations consistent with atomic ones."

src/heap/incremental-marking.h

 // 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.
 
 #ifndef V8_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 #include "src/cancelable-task.h"
 #include "src/execution.h"
 #include "src/heap/heap.h"
@@ skipping 47 matching lines @@
   explicit IncrementalMarking(Heap* heap);
 
   MarkingState marking_state(HeapObject* object) const {
     return MarkingState::Internal(object);
   }
 
   MarkingState marking_state(MemoryChunk* chunk) const {
     return MarkingState::Internal(chunk);
   }
 
-  void MarkBlack(HeapObject* object, int size);
-  void MarkGrey(HeapObject* object);
-
   // Transfers mark bits without requiring proper object headers.
   void TransferMark(Heap* heap, HeapObject* from, HeapObject* to);
 
   // Transfers color including live byte count, requiring properly set up
   // objects.
   template <MarkBit::AccessMode access_mode = MarkBit::NON_ATOMIC>
   V8_INLINE void TransferColor(HeapObject* from, HeapObject* to) {
     if (ObjectMarking::IsBlack<access_mode>(to, marking_state(to))) {
       DCHECK(black_allocation());
       return;
     }
 
     DCHECK(ObjectMarking::IsWhite<access_mode>(to, marking_state(to)));
     if (ObjectMarking::IsGrey<access_mode>(from, marking_state(from))) {
-      ObjectMarking::WhiteToGrey<access_mode>(to, marking_state(to));
+      bool success =
+          ObjectMarking::WhiteToGrey<access_mode>(to, marking_state(to));
+      DCHECK(success);
+      USE(success);
     } else if (ObjectMarking::IsBlack<access_mode>(from, marking_state(from))) {
-      ObjectMarking::WhiteToBlack<access_mode>(to, marking_state(to));
+      bool success =
+          ObjectMarking::WhiteToBlack<access_mode>(to, marking_state(to));
+      DCHECK(success);
+      USE(success);
     }
   }
 
 
   State state() {
     DCHECK(state_ == STOPPED || FLAG_incremental_marking);
     return state_;
   }
 
   bool should_hurry() { return should_hurry_; }
@@ skipping 105 matching lines @@
   INLINE(void RecordWriteIntoCode(Code* host, RelocInfo* rinfo, Object* value));
   INLINE(void RecordWriteOfCodeEntry(JSFunction* host, Object** slot,
                                      Code* value));
 
   void RecordWriteSlow(HeapObject* obj, Object** slot, Object* value);
   void RecordWriteIntoCodeSlow(Code* host, RelocInfo* rinfo, Object* value);
   void RecordWriteOfCodeEntrySlow(JSFunction* host, Object** slot, Code* value);
   void RecordCodeTargetPatch(Code* host, Address pc, HeapObject* value);
   void RecordCodeTargetPatch(Address pc, HeapObject* value);
 
-  void WhiteToGreyAndPush(HeapObject* obj);
+  // Returns true if the function succeeds in transitioning the object
+  // from white to grey.
+  bool WhiteToGreyAndPush(HeapObject* obj);
 
   inline void SetOldSpacePageFlags(MemoryChunk* chunk) {
     SetOldSpacePageFlags(chunk, IsMarking(), IsCompacting());
   }
 
   inline void SetNewSpacePageFlags(Page* chunk) {
     SetNewSpacePageFlags(chunk, IsMarking());
   }
 
   bool IsCompacting() { return IsMarking() && is_compacting_; }
@@ skipping 113 matching lines @@
 
   Observer new_generation_observer_;
   Observer old_generation_observer_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_