Extract FreezeHooks and make them testable (#4654)

kotlin-native/runtime/src/main/cpp/FreezeHooks.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+#include "FreezeHooks.hpp"
+
+#include "Memory.h"
+#include "Types.h"
+#include "WorkerBoundReference.h"
+
+using namespace kotlin;
+
+namespace {
+
+void (*g_hookOverrideForTesting)(ObjHeader*) = nullptr;
+
+NO_INLINE void RunFreezeHooksImpl(ObjHeader* object, const TypeInfo* type) noexcept {
+    if (g_hookOverrideForTesting != nullptr) {
+        g_hookOverrideForTesting(object);
+        return;
+    }
+    // TODO: Consider some global registration.
+    if (type == theWorkerBoundReferenceTypeInfo) {
+        WorkerBoundReferenceFreezeHook(object);
+    }
+}
+
+} // namespace
+
+void kotlin::RunFreezeHooks(ObjHeader* object) noexcept {
+    auto* type = object->type_info();
+    if ((type->flags_ & TF_HAS_FREEZE_HOOK) == 0) {
+        return;
+    }
+    // This is a cold path.
+    RunFreezeHooksImpl(object, type);
+}
+
+void kotlin::SetFreezeHookForTesting(void (*hook)(ObjHeader*)) noexcept {
+    g_hookOverrideForTesting = hook;
+}