You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
131 lines
4.5 KiB
131 lines
4.5 KiB
10 years ago
|
(*
|
||
|
|
* Copyright (c) 2014 - Facebook. All rights reserved.
|
||
|
|
*)
|
||
|
|
|
||
|
|
open Utils
|
||
|
|
|
||
|
|
module L = Logging
|
||
|
|
|
||
|
|
type t
|
||
|
|
|
||
|
|
module ConstantMap = Map.Make(struct
|
||
|
|
type t = string
|
||
|
|
let compare = string_compare
|
||
|
|
end)
|
||
|
|
|
||
|
|
let string_widening_limit = 1000
|
||
|
|
let verbose = false
|
||
|
|
|
||
|
|
(* Merge two constant maps by adding keys as necessary *)
|
||
|
|
let merge_values key c1_opt c2_opt =
|
||
|
|
match c1_opt, c2_opt with
|
||
|
|
| Some (Some c1), Some (Some c2) when Sil.const_equal c1 c2 -> Some (Some c1)
|
||
|
|
| Some c, None
|
||
|
|
| None, Some c -> Some c
|
||
|
|
| _ -> Some None
|
||
|
|
|
||
|
|
(** Dataflow struct *)
|
||
|
|
module ConstantFlow = Dataflow.MakeDF(struct
|
||
|
|
type t = (Sil.const option) ConstantMap.t
|
||
|
|
|
||
|
|
let pp fmt constants =
|
||
|
|
let print_kv k = function
|
||
|
|
| Some v -> Format.fprintf fmt " %s -> %a@." k (Sil.pp_const pe_text) v
|
||
|
|
| _ -> Format.fprintf fmt " %s -> None@." k in
|
||
|
|
Format.fprintf fmt "[@.";
|
||
|
|
ConstantMap.iter print_kv constants;
|
||
|
|
Format.fprintf fmt "]@."
|
||
|
|
|
||
|
|
(* Item-wise equality where values are equal iff
|
||
|
|
- both are None
|
||
|
|
- both are a constant and equal wrt. Sil.const_equal *)
|
||
|
|
let equal m n = ConstantMap.equal (opt_equal Sil.const_equal) m n
|
||
|
|
|
||
|
|
let join = ConstantMap.merge merge_values
|
||
|
|
|
||
|
|
let proc_throws pn = Dataflow.DontKnow
|
||
|
|
|
||
|
|
let do_node node constants =
|
||
|
|
|
||
|
|
let do_instr constants instr =
|
||
|
|
try
|
||
|
|
let update key value constants =
|
||
|
|
ConstantMap.merge
|
||
|
|
merge_values
|
||
|
|
constants
|
||
|
|
(ConstantMap.add key value ConstantMap.empty) in
|
||
|
|
|
||
|
|
match instr with
|
||
|
|
| Sil.Letderef (i, Sil.Lvar p, _, _) -> (* tmp = var *)
|
||
|
|
let lvar = Ident.to_string i in
|
||
|
|
let rvar = Sil.pvar_to_string p in
|
||
|
|
update lvar (ConstantMap.find rvar constants) constants
|
||
|
|
|
||
|
|
| Sil.Set (Sil.Lvar p, _, Sil.Const c, _) -> (* var = const *)
|
||
|
|
update (Sil.pvar_to_string p) (Some c) constants
|
||
|
|
|
||
|
|
| Sil.Set (Sil.Lvar p, _, Sil.Var i, _) -> (* var = tmp *)
|
||
|
|
let lvar = Sil.pvar_to_string p in
|
||
|
|
let rvar = Ident.to_string i in
|
||
|
|
update lvar (ConstantMap.find rvar constants) constants
|
||
|
|
|
||
|
|
(* Handle propagation of string with StringBuilder. Does not handle null case *)
|
||
|
|
| Sil.Call (_, Sil.Const (Sil.Cfun pn), (Sil.Var sb, _):: [], _, _)
|
||
|
|
when Procname.java_get_class pn = "java.lang.StringBuilder"
|
||
|
|
&& Procname.java_get_method pn = "<init>" -> (* StringBuilder.<init> *)
|
||
|
|
update (Ident.to_string sb) (Some (Sil.Cstr "")) constants
|
||
|
|
|
||
|
|
| Sil.Call (i:: [], Sil.Const (Sil.Cfun pn), (Sil.Var i1, _):: [], _, _)
|
||
|
|
when Procname.java_get_class pn = "java.lang.StringBuilder"
|
||
|
|
&& Procname.java_get_method pn = "toString" -> (* StringBuilder.toString *)
|
||
|
|
let lvar = Ident.to_string i in
|
||
|
|
let rvar = Ident.to_string i1 in
|
||
|
|
update lvar (ConstantMap.find rvar constants) constants
|
||
|
|
|
||
|
|
| Sil.Call (i:: [], Sil.Const (Sil.Cfun pn), (Sil.Var i1, _):: (Sil.Var i2, _):: [], _, _)
|
||
|
|
when Procname.java_get_class pn = "java.lang.StringBuilder"
|
||
|
|
&& Procname.java_get_method pn = "append" -> (* StringBuilder.append *)
|
||
|
|
let lvar = Ident.to_string i in
|
||
|
|
let rvar1 = Ident.to_string i1 in
|
||
|
|
let rvar2 = Ident.to_string i2 in
|
||
|
|
(match ConstantMap.find rvar1 constants, ConstantMap.find rvar2 constants with
|
||
|
|
| Some (Sil.Cstr s1), Some (Sil.Cstr s2) ->
|
||
|
|
begin
|
||
|
|
let s = s1 ^ s2 in
|
||
|
|
let u =
|
||
|
|
if String.length s < string_widening_limit then
|
||
|
|
Some (Sil.Cstr s)
|
||
|
|
else
|
||
|
|
None in
|
||
|
|
update lvar u constants
|
||
|
|
end
|
||
|
|
| _ -> constants)
|
||
|
|
|
||
|
|
| _ -> constants
|
||
|
|
with Not_found -> constants in
|
||
|
|
|
||
|
|
if verbose then
|
||
|
|
begin
|
||
|
|
L.stdout "Node %i:" (Cfg.Node.get_id node);
|
||
|
|
L.stdout "%a" pp constants;
|
||
|
|
list_iter
|
||
|
|
(fun instr -> L.stdout "%a@." (Sil.pp_instr pe_text) instr)
|
||
|
|
(Cfg.Node.get_instrs node)
|
||
|
|
end;
|
||
|
|
let constants =
|
||
|
|
list_fold_left
|
||
|
|
do_instr
|
||
|
|
constants
|
||
|
|
(Cfg.Node.get_instrs node) in
|
||
|
|
if verbose then L.stdout "%a\n@." pp constants;
|
||
|
|
[constants], [constants]
|
||
|
|
end)
|
||
|
|
|
||
|
|
let run proc_desc =
|
||
|
|
let transitions = ConstantFlow.run proc_desc ConstantMap.empty in
|
||
|
|
let get_constants node =
|
||
|
|
match transitions node with
|
||
|
|
| ConstantFlow.Transition (_, post_states, _) -> ConstantFlow.join post_states ConstantMap.empty
|
||
|
|
| ConstantFlow.Dead_state -> ConstantMap.empty in
|
||
|
|
get_constants
|