Prototype of mark-and-compact support for Harmony weak maps.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index efdb5499d212ef55c16cc214f5a088736d47553e..b14ff912707f0ae6bc1d40b8634dd7561ad7c730 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -1292,6 +1292,10 @@ class ScavengingVisitor : public StaticVisitorBase {
                     &ObjectEvacuationStrategy<POINTER_OBJECT>::
                         template VisitSpecialized<SharedFunctionInfo::kSize>);
 
+    table_.Register(kVisitJSWeakMap,
+                    &ObjectEvacuationStrategy<POINTER_OBJECT>::
+                    Visit);
+
     table_.Register(kVisitJSRegExp,
                     &ObjectEvacuationStrategy<POINTER_OBJECT>::
                     Visit);
@@ -2210,6 +2214,8 @@ bool Heap::CreateInitialObjects() {
   // Handling of script id generation is in FACTORY->NewScript.
   set_last_script_id(undefined_value());
 
+  set_encountered_weak_maps(Smi::FromInt(0));
+
   // Initialize keyed lookup cache.
   isolate_->keyed_lookup_cache()->Clear();