The compiler task queue code that makes weak global handles into strong global handles in select_for_compilation, could set a flag that the compileTask is active, so that it doesn't have to ask is_weak_global_handle() about the holders, which is expensive (lock and several SafeFetch loads).

bool CompileTask::is_unloaded() const {
  return _method_holder != NULL && JNIHandles::is_weak_global_handle(_method_holder) && JNIHandles::is_global_weak_cleared(_method_holder);
}

// Replace weak handles by strong handles to avoid unloading during compilation.
CompileTask* CompileTask::select_for_compilation() {
  if (is_unloaded()) {
    // Guard against concurrent class unloading
    return NULL;
  }
  Thread* thread = Thread::current();
  assert(_method->method_holder()->is_loader_alive(), "should be alive");
  Handle method_holder(thread, _method->method_holder()->klass_holder());
  JNIHandles::destroy_weak_global(_method_holder);
  JNIHandles::destroy_weak_global(_hot_method_holder);
  _method_holder = JNIHandles::make_global(method_holder);
  if (_hot_method != NULL) {
    _hot_method_holder = JNIHandles::make_global(Handle(thread, _hot_method->method_holder()->klass_holder()));
  }
  return this;
}