如何使用frama-c命令处理printf(& quot;和)和scanf(& amp;")?

我正在使用此代码生成C程序的控制流程图.对于除 printf 和 scanf 之类的内置功能以外的所有功能，它都可以正常工作.我可以在此代码中进行哪些更改以按原样输出内置函数?

I am using this code to generate the control flow graph of a C program. It is working fine for all the function except built-in function like printf and scanf. What can I change in this code to output the built in function as it is?

open Cil
open Cil_types
let print_stmt out =
function
| Instr i -> !Ast_printer.d_instr out i
| Return _ -> Format.pp_print_string out "<return>"
| Goto _ -> Format.pp_print_string out "<goto>"
| Break _ -> Format.pp_print_string out "<break>"
| Continue _ -> Format.pp_print_string out "<continue>"
| If (e,_,_,_) -> Format.fprintf out "if %a" !Ast_printer.d_exp e
| Switch(e,_,_,_) -> Format.fprintf out "switch %a" !Ast_printer.d_exp e
| Loop _ -> Format.fprintf out "<loop>"
| Block _ -> Format.fprintf out "<enter block>"
| UnspecifiedSequence _ -> Format.fprintf out "<enter unspecified sequence>"
| TryFinally _ | TryExcept _ -> Format.fprintf out "<try>"

class print_cfg out =
object
inherit Visitor.frama_c_inplace

method vstmt_aux s =
Format.fprintf out "s%d@[[label=\"%a\"]@];@\n" s.sid print_stmt s.skind;
List.iter 
  (fun succ -> Format.fprintf out "s%d -> s%d;@\n" s.sid succ.sid)
  s.succs;
DoChildren
method vglob_aux g =
match g with
  | GFun(f,loc) ->
      Format.fprintf out "@[<hov 2>subgraph cluster_%a {@\n\
                         graph [label=\"%a\"];@\n" 
        Cil_datatype.Varinfo.pretty f.svar
        Cil_datatype.Varinfo.pretty f.svar;
      ChangeDoChildrenPost([g], fun g -> Format.fprintf out "}@\n@]"; g)
  | _ -> SkipChildren

 method vfile f =
 Format.fprintf out "@[<hov 2>digraph cfg {@\n";
 ChangeDoChildrenPost (f,fun f -> Format.fprintf out "}@."; f)
 end

 let run () =
 let chan = open_out "cfg.out" in
 let fmt = Format.formatter_of_out_channel chan in
 Visitor.visitFramacFileSameGlobals (new print_cfg fmt) (Ast.get())

 let () = Db.Main.extend run