/**
  * Computes the control flow graph starting at the given root node.
  * 
  * @param \PHPParser_Node $node
  * 
  * @return ControlFlowGraph
  */
 public static function computeGraph(\PHPParser_Node $node)
 {
     $cfa = new self();
     $cfa->process($node);
     return $cfa->getGraph();
 }