4 files changed, 23 insertions, 1 deletions
diff --git a/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp b/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
index 48ed9b3c8d..a133fac961 100644
--- a/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/GlobalObject.cpp
@@ -65,6 +65,7 @@
 #include <LibJS/Runtime/PromiseConstructor.h>
 #include <LibJS/Runtime/PromisePrototype.h>
 #include <LibJS/Runtime/ProxyConstructor.h>
+#include <LibJS/Runtime/Realm.h>
 #include <LibJS/Runtime/ReflectObject.h>
 #include <LibJS/Runtime/RegExpConstructor.h>
 #include <LibJS/Runtime/RegExpPrototype.h>
@@ -318,6 +319,16 @@ void GlobalObject::visit_edges(Visitor& visitor)
 #undef __JS_ENUMERATE
 }
 
+Realm* GlobalObject::associated_realm()
+{
+    return m_associated_realm;
+}
+
+void GlobalObject::set_associated_realm(Badge<Realm>, Realm& realm)
+{
+    m_associated_realm = &realm;
+}
+
 JS_DEFINE_NATIVE_FUNCTION(GlobalObject::gc)
 {
 #ifdef __serenity__
diff --git a/Userland/Libraries/LibJS/Runtime/GlobalObject.h b/Userland/Libraries/LibJS/Runtime/GlobalObject.h
index 321fd3aeed..32387a0eef 100644
--- a/Userland/Libraries/LibJS/Runtime/GlobalObject.h
+++ b/Userland/Libraries/LibJS/Runtime/GlobalObject.h
@@ -23,6 +23,9 @@ public:
 
     Console& console() { return *m_console; }
 
+    Realm* associated_realm();
+    void set_associated_realm(Badge<Realm>, Realm&);
+
     Shape* empty_object_shape() { return m_empty_object_shape; }
 
     Shape* new_object_shape() { return m_new_object_shape; }
@@ -88,6 +91,8 @@ private:
 
     NonnullOwnPtr<Console> m_console;
 
+    WeakPtr<Realm> m_associated_realm;
+
     Shape* m_empty_object_shape { nullptr };
     Shape* m_new_object_shape { nullptr };
     Shape* m_new_ordinary_function_prototype_object_shape { nullptr };
diff --git a/Userland/Libraries/LibJS/Runtime/Realm.cpp b/Userland/Libraries/LibJS/Runtime/Realm.cpp
index 1082f0804f..eb324077be 100644
--- a/Userland/Libraries/LibJS/Runtime/Realm.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Realm.cpp
@@ -14,6 +14,9 @@ void Realm::set_global_object(GlobalObject& global_object, Object* this_value)
     // NOTE: Step 1 is not supported, the global object must be allocated elsewhere.
     // 2. Assert: Type(globalObj) is Object.
 
+    // Non-standard
+    global_object.set_associated_realm({}, *this);
+
     // 3. If thisValue is undefined, set thisValue to globalObj.
     if (!this_value)
         this_value = &global_object;
diff --git a/Userland/Libraries/LibJS/Runtime/Realm.h b/Userland/Libraries/LibJS/Runtime/Realm.h
index bd4d25d5e2..3c3820433a 100644
--- a/Userland/Libraries/LibJS/Runtime/Realm.h
+++ b/Userland/Libraries/LibJS/Runtime/Realm.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <AK/Weakable.h>
 #include <LibJS/Heap/Cell.h>
 #include <LibJS/Runtime/GlobalEnvironment.h>
 #include <LibJS/Runtime/GlobalObject.h>
@@ -13,7 +14,9 @@
 namespace JS {
 
 // 9.3 Realms, https://tc39.es/ecma262/#realm-record
-class Realm final : public Cell {
+class Realm final
+    : public Cell
+    , public Weakable<Realm> {
 public:
     Realm() = default;