[heap] Black allocation.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 1278c2a50d8acb4e406920852b409d874a3770f4..fe20637a3dd74efbd5e73e08c89013501725c411 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -2038,13 +2038,14 @@ void WeakCell::clear() {
 
 void WeakCell::initialize(HeapObject* val) {
   WRITE_FIELD(this, kValueOffset, val);
-  Heap* heap = GetHeap();
   // We just have to execute the generational barrier here because we never
   // mark through a weak cell and collect evacuation candidates when we process
   // all weak cells.
-  if (heap->InNewSpace(val)) {
-    heap->RecordWrite(address(), kValueOffset);
-  }
+  WriteBarrierMode mode =
+      Page::FromAddress(this->address())->IsFlagSet(Page::BLACK_PAGE)
+          ? UPDATE_WRITE_BARRIER

[ulan, 2016/02/10 10:27:39]

Invoking the marking visitor of the weak cell might be more consistent.

The same holds for TransitionArray, WeakCollection, JSArrayBuffer, JSFunction,
SharedFunctionInfo, Map

[Hannes Payer (out of office), 2016/02/11 18:18:07]

As discussed offline, this change was done on purpose. WeakCells on black pages
become strong. If floating garbage increases significantly because of that
change, we have to look into that problem.

+          : UPDATE_WEAK_WRITE_BARRIER;
+  CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kValueOffset, val, mode);
 }