这是一个具体示例,说明如何为每个局部和全局变量打印由给定函数中每个语句之前的 Value 计算的结果(从下到上读取函数):
open Cil_types
(* Prints the value associated to variable [vi] before [stmt]. *)
let pretty_vi fmt stmt vi =
let kinstr = Kstmt stmt in (* make a kinstr from a stmt *)
let lval = (Var vi, NoOffset) in (* make an lval from a varinfo *)
let loc = (* make a location from a kinstr + an lval *)
!Db.Value.lval_to_loc kinstr ~with_alarms:CilE.warn_none_mode lval
in
Db.Value.fold_state_callstack
(fun state () ->
(* for each state in the callstack *)
let value = Db.Value.find state loc in (* obtain value for location *)
Format.fprintf fmt "%a -> %a@." Printer.pp_varinfo vi
Locations.Location_Bytes.pretty value (* print mapping *)
) () ~after:false kinstr
(* Prints the state at statement [stmt] for each local variable in [kf],
and for each global variable. *)
let pretty_local_and_global_vars kf fmt stmt =
let locals = Kernel_function.get_locals kf in
List.iter (fun vi -> pretty_vi fmt stmt vi) locals;
Globals.Vars.iter (fun vi _ -> pretty_vi fmt stmt vi)
(* Visits each statement in [kf] and prints the result of Value before the
statement. *)
class stmt_val_visitor kf =
object (self)
inherit Visitor.frama_c_inplace
method! vstmt_aux stmt =
(match stmt.skind with
| Instr _ ->
Format.printf "state for all variables before stmt: %a@.%a@."
Printer.pp_stmt stmt (pretty_local_and_global_vars kf) stmt
| _ -> ());
Cil.DoChildren
end
(* usage: frama-c file.c -load-script print_vals.ml *)
let () =
Db.Main.extend (fun () ->
Format.printf "computing value...@.";
!Db.Value.compute ();
let fun_name = "main" in
Format.printf "visiting function: %s@." fun_name;
let kf_vis = new stmt_val_visitor in
let kf = Globals.Functions.find_by_name fun_name in
let fundec = Kernel_function.get_definition kf in
ignore (Visitor.visitFramacFunction (kf_vis kf) fundec);
Format.printf "done!@.")
这远非理想,而且输出比简单地使用更难看Cvalue.Model.pretty state
,但它可以作为进一步修改的基础。
该脚本已使用 Frama-C Magnesium 进行了测试。
要检索语句后~after:false
的状态,只需将参数fold_state_callstack
替换为~after:true
。我以前版本的代码使用了一个已经为 pre-state 绑定了该值的函数,但是没有为 post-state 导出这样的函数,所以我们必须使用fold_state_callstack
(顺便说一句更强大,因为它允许检索特定状态每个调用堆栈)。