Make objects embedded in optimized code weak.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 2fea50a175831232315430db45291f63b62a5cae..ed5f3ee96abe7d2a394ce13ac3b5ed5177eaf17a 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -89,9 +89,7 @@ void LCodeGen::FinishCode(Handle<Code> code) {
   ASSERT(is_done());
   code->set_stack_slots(GetStackSlotCount());
   code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
-  if (FLAG_weak_embedded_maps_in_optimized_code) {
-    RegisterDependentCodeForEmbeddedMaps(code);
-  }
+  RegisterDependentCodeForEmbeddedMaps(code);
   PopulateDeoptimizationData(code);
   info()->CommitDependencies(code);
 }
@@ -756,14 +754,16 @@ void LCodeGen::DeoptimizeIf(Condition cc,
 
 void LCodeGen::RegisterDependentCodeForEmbeddedMaps(Handle<Code> code) {
   ZoneList<Handle<Map> > maps(1, zone());
+  ZoneList<Handle<JSObject> > objects(1, zone());
   int mode_mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
   for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
-    RelocInfo::Mode mode = it.rinfo()->rmode();
-    if (mode == RelocInfo::EMBEDDED_OBJECT &&
-        it.rinfo()->target_object()->IsMap()) {
-      Handle<Map> map(Map::cast(it.rinfo()->target_object()));
-      if (map->CanTransition()) {
+    if (Code::IsWeakEmbeddedObject(code->kind(), it.rinfo()->target_object())) {
+      if (it.rinfo()->target_object()->IsMap()) {
+        Handle<Map> map(Map::cast(it.rinfo()->target_object()));
         maps.Add(map, zone());
+      } else if (it.rinfo()->target_object()->IsJSObject()) {
+        Handle<JSObject> object(JSObject::cast(it.rinfo()->target_object()));
+        objects.Add(object, zone());
       }
     }
   }
@@ -776,6 +776,9 @@ void LCodeGen::RegisterDependentCodeForEmbeddedMaps(Handle<Code> code) {
   for (int i = 0; i < maps.length(); i++) {
     maps.at(i)->AddDependentCode(DependentCode::kWeaklyEmbeddedGroup, code);
   }
+  for (int i = 0; i < objects.length(); i++) {
+    AddWeakObjectToCodeDependency(isolate()->heap(), objects.at(i), code);
+  }
 }