[heap] Provide ObjectMarking with marking transitions

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 2e6ded546f45ecc33b2ff90b31d57d89d59685a3..b3ebd11d35fc78092aee6f414fcb1586bdf73d30 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -2990,7 +2990,8 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
   AllocationStep(object->address(), object_size);
 
   if (heap()->incremental_marking()->black_allocation()) {
-    Marking::MarkBlack(ObjectMarking::MarkBitFrom(object));
+    // We cannot use ObjectMarking here as the object still lacks a size.

[Hannes Payer (out of office), 2017/01/18 14:43:35]

This one is really unfortunate. However, we do not need the live byte count for
large objects because we can always check the liveness of the LO and return its
size.

[Michael Lippautz, 2017/01/18 15:58:07]

Acknowledged.

+    Marking::WhiteToBlack(ObjectMarking::MarkBitFrom(object));
     MemoryChunk::IncrementLiveBytes(object, object_size);
   }
   return object;
@@ -3039,9 +3040,8 @@ void LargeObjectSpace::ClearMarkingStateOfLiveObjects() {
   LargePage* current = first_page_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
-    MarkBit mark_bit = ObjectMarking::MarkBitFrom(object);
-    DCHECK(Marking::IsBlack(mark_bit));
-    Marking::BlackToWhite(mark_bit);
+    DCHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(object)));
+    ObjectMarking::BlackToWhite(object);
     Page::FromAddress(object->address())->ResetProgressBar();
     Page::FromAddress(object->address())->ResetLiveBytes();
     current = current->next_page();