LibJS+LibWeb: Make CyclicModule & GraphLoadingState GC-allocated

This allows them to participate in the ownership graph and fixes a
lifetime issue in module loading found by ASAN.

Co-Authored-By: networkException <networkexception@serenityos.org>

Userland/Libraries/LibJS/CyclicModule.cpp

@@ -35,8 +35,17 @@ void CyclicModule::visit_edges(Cell::Visitor& visitor)
         visitor.visit(loaded_module.module);
 }
 
+void GraphLoadingState::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(promise_capability);
+    visitor.visit(host_defined);
+    for (auto* module : visited)
+        visitor.visit(*module);
+}
+
 // 16.2.1.5.1 LoadRequestedModules ( [ hostDefined ] ), https://tc39.es/ecma262/#sec-LoadRequestedModules
-PromiseCapability& CyclicModule::load_requested_modules(JS::Realm& realm, Optional<GraphLoadingState::HostDefined> host_defined)
+PromiseCapability& CyclicModule::load_requested_modules(JS::Realm& realm, GCPtr<GraphLoadingState::HostDefined> host_defined)
 {
     // 1. If hostDefined is not present, let hostDefined be EMPTY.
     // NOTE: The empty state is handled by hostDefined being an optional without value.
@@ -45,7 +54,7 @@ PromiseCapability& CyclicModule::load_requested_modules(JS::Realm& realm, Option
     auto promise_capability = MUST(new_promise_capability(realm.vm(), realm.intrinsics().promise_constructor()));
 
     // 3. Let state be the GraphLoadingState Record { [[IsLoading]]: true, [[PendingModulesCount]]: 1, [[Visited]]: « », [[PromiseCapability]]: pc, [[HostDefined]]: hostDefined }.
-    auto state = GraphLoadingState { .promise_capability = promise_capability, .is_loading = true, .pending_module_count = 1, .visited = {}, .host_defined = move(host_defined) };
+    auto state = heap().allocate_without_realm<GraphLoadingState>(promise_capability, true, 1, HashTable<CyclicModule*> {}, move(host_defined));
 
     // 4. Perform InnerModuleLoading(state, module).
     inner_module_loading(state);

Userland/Libraries/LibJS/CyclicModule.h

@@ -25,18 +25,33 @@ enum class ModuleStatus {
 class CyclicModule;
 
 // https://tc39.es/ecma262/#graphloadingstate-record
-struct GraphLoadingState {
-    struct HostDefined {
-        virtual ~HostDefined() = default;
+struct GraphLoadingState : public Cell {
+    JS_CELL(GraphLoadingState, Cell);
 
-        virtual void visit_edges(Cell::Visitor&) { }
+public:
+    struct HostDefined : Cell {
+        JS_CELL(HostDefined, Cell);
+
+    public:
+        virtual ~HostDefined() = default;
     };
 
     GCPtr<PromiseCapability> promise_capability; // [[PromiseCapability]]
     bool is_loading { false };                   // [[IsLoading]]
     size_t pending_module_count { 0 };           // [[PendingModulesCount]]
     HashTable<CyclicModule*> visited;            // [[Visited]]
-    Optional<HostDefined> host_defined;          // [[HostDefined]]
+    GCPtr<HostDefined> host_defined;             // [[HostDefined]]
+
+private:
+    GraphLoadingState(GCPtr<PromiseCapability> promise_capability, bool is_loading, size_t pending_module_count, HashTable<CyclicModule*> visited, GCPtr<HostDefined> host_defined)
+        : promise_capability(move(promise_capability))
+        , is_loading(is_loading)
+        , pending_module_count(pending_module_count)
+        , visited(move(visited))
+        , host_defined(move(host_defined))
+    {
+    }
+    virtual void visit_edges(Cell::Visitor&) override;
 };
 
 // 16.2.1.5 Cyclic Module Records, https://tc39.es/ecma262/#cyclic-module-record
@@ -50,7 +65,7 @@ public:
     virtual ThrowCompletionOr<void> link(VM& vm) override final;
     virtual ThrowCompletionOr<Promise*> evaluate(VM& vm) override final;
 
-    virtual PromiseCapability& load_requested_modules(Realm&, Optional<GraphLoadingState::HostDefined>);
+    virtual PromiseCapability& load_requested_modules(Realm&, GCPtr<GraphLoadingState::HostDefined>);
     virtual void inner_module_loading(GraphLoadingState& state);
 
     Vector<ModuleRequest> const& requested_modules() const { return m_requested_modules; }

Userland/Libraries/LibJS/Runtime/VM.h

@@ -228,7 +228,7 @@ public:
     //       Our implementation of this proposal is outdated however, as such we try to adapt the proposal and living standard
     //       to match our implementation for now.
     // 16.2.1.8 HostLoadImportedModule ( referrer, moduleRequest, hostDefined, payload ), https://tc39.es/proposal-import-attributes/#sec-HostLoadImportedModule
-    Function<void(Realm&, Variant<NonnullGCPtr<Script>, NonnullGCPtr<CyclicModule>>, ModuleRequest const&, Optional<GraphLoadingState::HostDefined>, GraphLoadingState&)> host_load_imported_module;
+    Function<void(Realm&, Variant<NonnullGCPtr<Script>, NonnullGCPtr<CyclicModule>>, ModuleRequest const&, GCPtr<GraphLoadingState::HostDefined>, GraphLoadingState&)> host_load_imported_module;
 
     Function<ThrowCompletionOr<NonnullGCPtr<Module>>(ScriptOrModule, ModuleRequest const&)> host_resolve_imported_module;
     Function<ThrowCompletionOr<void>(ScriptOrModule, ModuleRequest, PromiseCapability const&)> host_import_module_dynamically;