get basicblock

Hi All

     When I using the method as following to get the basicblocks from function(.bc generated by clang 3.3) ,but it does not work. After comparing to past version of clang,the differences are that the basicblock lable in the IR generated by clang 3.3 are expressed by way of noting,like this:";<lable>:5".
     Now I could ask you how I can get the basicblock ?Thank you all!