diff --git a/src/heap.cc b/src/heap.cc
index e34b529..8f1ad94 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -854,6 +854,9 @@
   CompletelyClearInstanceofCache();
 
   if (is_compacting) FlushNumberStringCache();
+  if (FLAG_cleanup_code_caches_at_gc) {
+    polymorphic_code_cache()->set_cache(undefined_value());
+  }
 
   ClearNormalizedMapCaches();
 }
@@ -1037,9 +1040,10 @@
   scavenge_visitor.VisitPointer(BitCast<Object**>(&global_contexts_list_));
 
   new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
-  isolate_->global_handles()->IdentifyWeakIndependentHandles(
+  isolate_->global_handles()->IdentifyNewSpaceWeakIndependentHandles(
       &IsUnscavengedHeapObject);
-  isolate_->global_handles()->IterateWeakIndependentRoots(&scavenge_visitor);
+  isolate_->global_handles()->IterateNewSpaceWeakIndependentRoots(
+      &scavenge_visitor);
   new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
 
 
@@ -1638,6 +1642,11 @@
 }
 
 
+MaybeObject* Heap::AllocatePolymorphicCodeCache() {
+  return AllocateStruct(POLYMORPHIC_CODE_CACHE_TYPE);
+}
+
+
 const Heap::StringTypeTable Heap::string_type_table[] = {
 #define STRING_TYPE_ELEMENT(type, size, name, camel_name)                      \
   {type, size, k##camel_name##MapRootIndex},
@@ -2145,6 +2154,11 @@
   }
   set_non_monomorphic_cache(NumberDictionary::cast(obj));
 
+  { MaybeObject* maybe_obj = AllocatePolymorphicCodeCache();
+    if (!maybe_obj->ToObject(&obj)) return false;
+  }
+  set_polymorphic_code_cache(PolymorphicCodeCache::cast(obj));
+
   set_instanceof_cache_function(Smi::FromInt(0));
   set_instanceof_cache_map(Smi::FromInt(0));
   set_instanceof_cache_answer(Smi::FromInt(0));
@@ -4576,7 +4590,7 @@
       isolate_->global_handles()->IterateStrongRoots(v);
       break;
     case VISIT_ALL_IN_SCAVENGE:
-      isolate_->global_handles()->IterateStrongAndDependentRoots(v);
+      isolate_->global_handles()->IterateNewSpaceStrongAndDependentRoots(v);
       break;
     case VISIT_ALL_IN_SWEEP_NEWSPACE:
     case VISIT_ALL: