Rehash and clear deleted entries in weak collections during GC

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index ac595e6f5fb8d7b800dc22248d61549718e890d1..b55ed634dbb6984d88fbb93de2bad1db727bcf91 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -2550,6 +2550,11 @@ void MarkCompactCollector::ClearWeakCollections() {
           table->RemoveEntry(i);
         }
       }
+      // Rehash if more than 25% of the entries are deleted entries.
+      if ((table->NumberOfDeletedElements() << 1) > table->NumberOfElements()) {

[Hannes Payer (out of office), 2016/04/15 08:20:11]

Can you make that a constant?

[jochen (gone - plz use gerrit), 2016/04/15 08:21:28]

which one do you propose?

+        HandleScope scope(heap()->isolate());
+        table->Rehash(heap()->isolate()->factory()->undefined_value());
+      }
     }
     weak_collection_obj = weak_collection->next();
     weak_collection->set_next(heap()->undefined_value());