StackVisitor::Status operator()(StackVisitor& visitor)
 {
     if (m_currentFrame++ > 1) {
         m_jitType = visitor->codeBlock()->jitType();
         return StackVisitor::Done;
     }
     return StackVisitor::Continue;
 }
 StackVisitor::Status operator()(StackVisitor& visitor)
 {
     currentFrame++;
     if (currentFrame == targetFrame) {
         codeBlock = visitor->codeBlock();
         return StackVisitor::Done;
     }
     return StackVisitor::Continue;
 }