[heap] Provide ObjectMarking with marking transitions

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 9952b7953dfb154e73e81eccfb4e260a04a3e98b..0ad236be600bbf3a6c016f75c699485d6c634410 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -46,6 +46,54 @@ class ObjectMarking : public AllStatic {
     return Marking::Color(ObjectMarking::MarkBitFrom(obj));
   }
 
+  V8_INLINE static void MarkWhite(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    if (Marking::IsBlack(markbit)) {
+      MemoryChunk::IncrementLiveBytes(obj, -obj->Size());
+    }
+    Marking::MarkWhite(markbit);
+  }
+

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

Should we add DCHECKs to the transitions where we expect a color? The lower
level has the DCHECKs but this may change for whatever reason.

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

Done.

+  V8_INLINE static void BlackToWhite(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    Marking::BlackToWhite(markbit);
+    MemoryChunk::IncrementLiveBytes(obj, -obj->Size());
+  }
+
+  V8_INLINE static void GreyToWhite(HeapObject* obj) {
+    Marking::GreyToWhite(MarkBitFrom(obj));
+  }
+
+  V8_INLINE static void BlackToGrey(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    Marking::BlackToGrey(markbit);
+    MemoryChunk::IncrementLiveBytes(obj, -obj->Size());
+  }
+
+  V8_INLINE static void WhiteToGrey(HeapObject* obj) {
+    Marking::WhiteToGrey(MarkBitFrom(obj));
+  }
+
+  V8_INLINE static void WhiteToBlack(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    Marking::WhiteToBlack(markbit);
+    MemoryChunk::IncrementLiveBytes(obj, obj->Size());
+  }
+
+  V8_INLINE static void GreyToBlack(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    Marking::GreyToBlack(markbit);
+    MemoryChunk::IncrementLiveBytes(obj, obj->Size());
+  }
+
+  V8_INLINE static void AnyToGrey(HeapObject* obj) {
+    MarkBit markbit = MarkBitFrom(obj);
+    if (Marking::IsBlack(markbit)) {
+      MemoryChunk::IncrementLiveBytes(obj, -obj->Size());
+    }
+    Marking::AnyToGrey(markbit);
+  }
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ObjectMarking);
 };