LibJS: Remove the JS_TRACK_ZOMBIE_CELLS option

This feature had bitrotted somewhat and would trigger errors because
PrimitiveStrings were "destroyed" but because of this mode they were not
removed from the string cache. Even fixing that case running test-js
with the options still failed in more places.

Userland/Libraries/LibJS/Heap/Cell.h

@@ -24,18 +24,9 @@ public:
     bool is_marked() const { return m_mark; }
     void set_marked(bool b) { m_mark = b; }
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie()
-    {
-    }
-#endif
-
     enum class State {
         Live,
         Dead,
-#ifdef JS_TRACK_ZOMBIE_CELLS
-        Zombie,
-#endif
     };
 
     State state() const { return m_state; }

Userland/Libraries/LibJS/Heap/Heap.cpp

@@ -190,14 +190,6 @@ public:
             return;
         dbgln_if(HEAP_DEBUG, "  ! {}", &cell);
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-        if (cell.state() == Cell::State::Zombie) {
-            dbgln("BUG! Marking a zombie cell, {} @ {:p}", cell.class_name(), &cell);
-            cell.vm().dump_backtrace();
-            VERIFY_NOT_REACHED();
-        }
-#endif
-
         cell.set_marked(true);
         cell.visit_edges(*this);
     }
@@ -234,16 +226,7 @@ void Heap::sweep_dead_cells(bool print_report, const Core::ElapsedTimer& measure
         block.template for_each_cell_in_state<Cell::State::Live>([&](Cell* cell) {
             if (!cell->is_marked()) {
                 dbgln_if(HEAP_DEBUG, "  ~ {}", cell);
-#ifdef JS_TRACK_ZOMBIE_CELLS
+                block.deallocate(cell);
-                if (m_zombify_dead_cells) {
-                    cell->set_state(Cell::State::Zombie);
-                    cell->did_become_zombie();
-                } else {
-#endif
-                    block.deallocate(cell);
-#ifdef JS_TRACK_ZOMBIE_CELLS
-                }
-#endif
                 ++collected_cells;
                 collected_cell_bytes += block.cell_size();
             } else {

Userland/Libraries/LibJS/Heap/Heap.h

@@ -63,13 +63,6 @@ public:
     bool should_collect_on_every_allocation() const { return m_should_collect_on_every_allocation; }
     void set_should_collect_on_every_allocation(bool b) { m_should_collect_on_every_allocation = b; }
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    void set_zombify_dead_cells(bool b)
-    {
-        m_zombify_dead_cells = b;
-    }
-#endif
-
     void did_create_handle(Badge<HandleImpl>, HandleImpl&);
     void did_destroy_handle(Badge<HandleImpl>, HandleImpl&);
 
@@ -132,10 +125,6 @@ private:
     bool m_should_gc_when_deferral_ends { false };
 
     bool m_collecting_garbage { false };
-
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    bool m_zombify_dead_cells { false };
-#endif
 };
 
 }

Userland/Libraries/LibJS/Runtime/FinalizationRegistry.h

@@ -35,13 +35,6 @@ public:
 private:
     virtual void visit_edges(Visitor& visitor) override;
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override
-    {
-        deregister();
-    }
-#endif
-
     FunctionObject* m_cleanup_callback { nullptr };
 
     struct FinalizationRecord {

Userland/Libraries/LibJS/Runtime/Shape.cpp

@@ -247,11 +247,4 @@ FLATTEN void Shape::add_property_without_transition(PropertyKey const& property_
     add_property_without_transition(property_name.to_string_or_symbol(), attributes);
 }
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-void Shape::did_become_zombie()
-{
-    revoke_weak_ptrs();
-}
-#endif
-
 }

Userland/Libraries/LibJS/Runtime/Shape.h

@@ -89,10 +89,6 @@ private:
     virtual const char* class_name() const override { return "Shape"; }
     virtual void visit_edges(Visitor&) override;
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override;
-#endif
-
     Shape* get_or_prune_cached_forward_transition(TransitionKey const&);
     Shape* get_or_prune_cached_prototype_transition(Object* prototype);
 

Userland/Libraries/LibJS/Runtime/WeakMap.h

@@ -30,13 +30,6 @@ public:
     virtual void remove_dead_cells(Badge<Heap>) override;
 
 private:
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override
-    {
-        deregister();
-    }
-#endif
-
     void visit_edges(Visitor&) override;
 
     HashMap<Cell*, Value> m_values; // This stores Cell pointers instead of Object pointers to aide with sweeping

Userland/Libraries/LibJS/Runtime/WeakRef.h

@@ -32,13 +32,6 @@ public:
 private:
     virtual void visit_edges(Visitor&) override;
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override
-    {
-        deregister();
-    }
-#endif
-
     Object* m_value { nullptr };
     u32 m_last_execution_generation { 0 };
 };

Userland/Libraries/LibJS/Runtime/WeakSet.h

@@ -30,13 +30,6 @@ public:
     virtual void remove_dead_cells(Badge<Heap>) override;
 
 private:
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override
-    {
-        deregister();
-    }
-#endif
-
     HashTable<Cell*> m_values; // This stores Cell pointers instead of Object pointers to aide with sweeping
 };
 

Userland/Libraries/LibTest/JavaScriptTestRunner.h

@@ -116,9 +116,6 @@ static consteval size_t __testjs_last()
 static constexpr auto TOP_LEVEL_TEST_NAME = "__$$TOP_LEVEL$$__";
 extern RefPtr<JS::VM> g_vm;
 extern bool g_collect_on_every_allocation;
-#ifdef JS_TRACK_ZOMBIE_CELLS
-extern bool g_zombify_dead_cells;
-#endif
 extern bool g_run_bytecode;
 extern String g_currently_running_test;
 struct FunctionWithLength {
@@ -291,10 +288,6 @@ inline JSFileResult TestRunner::run_file_test(const String& test_path)
 
     interpreter->heap().set_should_collect_on_every_allocation(g_collect_on_every_allocation);
 
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    interpreter->heap().set_zombify_dead_cells(g_zombify_dead_cells);
-#endif
-
     if (g_run_file) {
         auto result = g_run_file(test_path, *interpreter);
         if (result.is_error() && result.error() == RunFileHookResult::SkipFile) {

Userland/Libraries/LibTest/JavaScriptTestRunnerMain.cpp

@@ -19,9 +19,6 @@ namespace JS {
 
 RefPtr<::JS::VM> g_vm;
 bool g_collect_on_every_allocation = false;
-#ifdef JS_TRACK_ZOMBIE_CELLS
-bool g_zombify_dead_cells = false;
-#endif
 bool g_run_bytecode = false;
 String g_currently_running_test;
 HashMap<String, FunctionWithLength> s_exposed_global_functions;
@@ -112,9 +109,6 @@ int main(int argc, char** argv)
     });
     args_parser.add_option(print_json, "Show results as JSON", "json", 'j');
     args_parser.add_option(g_collect_on_every_allocation, "Collect garbage after every allocation", "collect-often", 'g');
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    args_parser.add_option(g_zombify_dead_cells, "Zombify dead cells (to catch missing GC marks)", "zombify-dead-cells", 'z');
-#endif
     args_parser.add_option(g_run_bytecode, "Use the bytecode interpreter", "run-bytecode", 'b');
     args_parser.add_option(JS::Bytecode::g_dump_bytecode, "Dump the bytecode", "dump-bytecode", 'd');
     args_parser.add_option(test_glob, "Only run tests matching the given glob", "filter", 'f', "glob");

Userland/Libraries/LibWeb/Bindings/Wrapper.h

@@ -24,13 +24,6 @@ protected:
         : Object(prototype)
     {
     }
-
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    virtual void did_become_zombie() override
-    {
-        revoke_weak_ptrs();
-    }
-#endif
 };
 
 }

Userland/Utilities/js.cpp

@@ -1370,10 +1370,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.add_option(s_strip_ansi, "Disable ANSI colors", "disable-ansi-colors", 'c');
     args_parser.add_option(s_disable_source_location_hints, "Disable source location hints", "disable-source-location-hints", 'h');
     args_parser.add_option(gc_on_every_allocation, "GC on every allocation", "gc-on-every-allocation", 'g');
-#ifdef JS_TRACK_ZOMBIE_CELLS
-    bool zombify_dead_cells = false;
-    args_parser.add_option(zombify_dead_cells, "Zombify dead cells (to catch missing GC marks)", "zombify-dead-cells", 'z');
-#endif
     args_parser.add_option(disable_syntax_highlight, "Disable live syntax highlighting", "no-syntax-highlight", 's');
     args_parser.add_positional_argument(script_paths, "Path to script files", "scripts", Core::ArgsParser::Required::No);
     args_parser.parse(arguments);
@@ -1416,9 +1412,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         ReplConsoleClient console_client(interpreter->global_object().console());
         interpreter->global_object().console().set_client(console_client);
         interpreter->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
-#ifdef JS_TRACK_ZOMBIE_CELLS
-        interpreter->heap().set_zombify_dead_cells(zombify_dead_cells);
-#endif
 
         auto& global_environment = interpreter->realm().global_environment();
 
@@ -1630,9 +1623,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         ReplConsoleClient console_client(interpreter->global_object().console());
         interpreter->global_object().console().set_client(console_client);
         interpreter->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
-#ifdef JS_TRACK_ZOMBIE_CELLS
-        interpreter->heap().set_zombify_dead_cells(zombify_dead_cells);
-#endif
 
         signal(SIGINT, [](int) {
             sigint_handler();