LibJS: Put zombie cell tracking code behind a compile-time flag

Since this is a debug-only feature, let's not have it impact GC marking
performance when you don't need it.

1 files changed, 7 insertions, 1 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/FinalizationRegistry.h b/Userland/Libraries/LibJS/Runtime/FinalizationRegistry.h
index 6affdcd6a3..681df05c3b 100644
--- a/Userland/Libraries/LibJS/Runtime/FinalizationRegistry.h
+++ b/Userland/Libraries/LibJS/Runtime/FinalizationRegistry.h
@@ -34,7 +34,13 @@ public:
 
 private:
     virtual void visit_edges(Visitor& visitor) override;
-    virtual void did_become_zombie() override { deregister(); }
+
+#ifdef JS_TRACK_ZOMBIE_CELLS
+    virtual void did_become_zombie() override
+    {
+        deregister();
+    }
+#endif
 
     FunctionObject* m_cleanup_callback { nullptr };