Allow hidden properties and implement GetIdentityHash

src/objects.cc

Index: src/objects.cc
===================================================================
--- src/objects.cc	(revision 1540)
+++ src/objects.cc	(working copy)
@@ -5171,6 +5171,26 @@
 }
 
 
+Object* JSObject::GetHiddenProperties(bool create_if_needed) {
+  String* key = Heap::hidden_symbol();
+  if (!this->HasProperty(key)) {
+    // Hidden properties object not found. Allocate a new hidden properties
+    // object if requested. Otherwise return the undefined value.
+    if (create_if_needed) {
+      Object* obj = Heap::AllocateJSObject(
+          Top::context()->global_context()->object_function());
+      if (obj->IsFailure()) {
+        return obj;
+      }
+      return this->SetProperty(key, obj, DONT_ENUM);
+    } else {
+      return Heap::undefined_value();
+    }
+  }
+  return this->GetProperty(key);
+}
+
+
 bool JSObject::HasElementWithReceiver(JSObject* receiver, uint32_t index) {
   // Check access rights if needed.
   if (IsAccessCheckNeeded() &&