Source file dhunk.ml
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type t = {
instructions : Dba.Instr.t array;
predecessors : int list array;
exits : int list;
}
module Share = Weak.Make (struct
include Dba.Instr
let equal = ( = )
let hash = Hashtbl.hash
end)
let share = Share.create 128
module G : sig
include Graph.Sig.G with type t = t and type V.t = int
val empty : t
val singleton : Dba.Instr.t -> t
val init : int -> (int -> Dba.Instr.t) -> t
end = struct
type nonrec t = t
let empty = { instructions = [||]; predecessors = [||]; exits = [] }
let singleton instr =
let instr = Share.merge share instr in
match instr with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ ->
{ instructions = [| instr |]; predecessors = [| [] |]; exits = [ 0 ] }
| Dba.Instr.Assert (Cst bv, 0) when Bitvector.is_zero bv ->
{
instructions = [| instr |];
predecessors = [| [ 0 ] |];
exits = [ 0 ];
}
| Dba.Instr.Assert _ | Dba.Instr.Assign _ | Dba.Instr.Assume _
| Dba.Instr.If _ | Dba.Instr.Nondet _ | Dba.Instr.SJump _
| Dba.Instr.Undef _ ->
raise (Invalid_argument "Instruction is not a terminator")
let init n f =
let exits = ref [] in
let predecessors = Array.make n [] in
let instructions =
Array.init n (fun i ->
let instr = Share.merge share (f i) in
match instr with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _
->
exits := i :: !exits;
instr
| Dba.Instr.If (_, JOuter _, fallthrough) ->
exits := i :: !exits;
predecessors.(fallthrough) <- i :: predecessors.(fallthrough);
instr
| Dba.Instr.If (_, JInner target, fallthrough) ->
predecessors.(target) <- i :: predecessors.(target);
predecessors.(fallthrough) <- i :: predecessors.(fallthrough);
instr
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
predecessors.(fallthrough) <- i :: predecessors.(fallthrough);
instr)
in
{ instructions; predecessors; exits = !exits }
module V : Graph.Sig.VERTEX with type t = int = struct
type t = int
let compare a b = a - b
let equal a b = a == b
let hash = Fun.id
type label = t
let create = Fun.id
let label = Fun.id
end
type vertex = V.t
module E : Graph.Sig.EDGE with type t = V.t * V.t and type vertex = V.t =
struct
type t = V.t * V.t
let compare = compare
type vertex = V.t
let src = fst
let dst = snd
type label = unit
let create src () dst = (src, dst)
let label _ = ()
end
type edge = E.t
let is_directed = true
let is_empty = function { instructions = [||]; _ } -> true | _ -> false
let nb_vertex { instructions; _ } = Array.length instructions
let nb_edges { predecessors; _ } =
Array.fold_left
(fun edges preds -> edges + List.length preds)
0 predecessors
let out_degree { instructions; _ } v =
match instructions.(v) with
| Dba.Instr.If (_, JInner _, _) -> 2
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> 0
| Dba.Instr.Assert _ | Dba.Instr.Assign _ | Dba.Instr.Assume _
| Dba.Instr.If _ | Dba.Instr.Nondet _ | Dba.Instr.SJump _
| Dba.Instr.Undef _ ->
1
let in_degree { predecessors; _ } v = List.length predecessors.(v)
let mem_vertex { instructions; _ } v = v < Array.length instructions
let mem_edge { instructions; _ } src dst =
match instructions.(src) with
| exception Invalid_argument _ -> false
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ ->
false
| Dba.Instr.If (_, JInner target, fallthrough) ->
dst = target || dst = fallthrough
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
dst = fallthrough
let mem_edge_e t (src, dst) = mem_edge t src dst
let find_edge t src dst =
if mem_edge t src dst then (src, dst) else raise Not_found
let find_all_edges t src dst =
if mem_edge t src dst then [ (src, dst) ] else []
let succ { instructions; _ } v =
match instructions.(v) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> []
| Dba.Instr.If (_, JInner target, fallthrough) -> [ target; fallthrough ]
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
[ fallthrough ]
let pred { predecessors; _ } v = predecessors.(v)
let succ_e t v = List.map (fun dst -> (v, dst)) (succ t v)
let pred_e t v = List.map (fun src -> (src, v)) (pred t v)
let iter_vertex f { instructions; _ } =
for i = 0 to Array.length instructions - 1 do
f i
done
let fold_vertex =
let rec loop f n i x = if i < n then loop f n (i + 1) (f i x) else x in
fun f { instructions; _ } x -> loop f (Array.length instructions) 0 x
let iter_edges f { instructions; _ } =
for i = 0 to Array.length instructions - 1 do
match instructions.(i) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ ->
()
| Dba.Instr.If (_, JInner target, fallthrough) ->
f i target;
f i fallthrough
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f i fallthrough
done
let fold_edges =
let rec loop instructions f n i x =
if i < n then
loop instructions f n (i + 1)
(match instructions.(i) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _
->
x
| Dba.Instr.If (_, JInner target, fallthrough) ->
f i target (f i fallthrough x)
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f i fallthrough x)
else x
in
fun f { instructions; _ } x ->
loop instructions f (Array.length instructions) 0 x
let iter_edges_e f t = iter_edges (fun src dst -> f (src, dst)) t
let fold_edges_e f t x = fold_edges (fun src dst x -> f (src, dst) x) t x
let map_vertex f { instructions; _ } =
let size = Array.length instructions in
let transient = Array.make size (Dba.Instr.stop (Some Dba.KO)) in
for i = 0 to size - 1 do
transient.(f i) <-
Share.merge share
(Dba_types.Instruction.reloc ~inner:f instructions.(i))
done;
init size (fun i -> transient.(i))
let iter_succ f { instructions; _ } v =
match instructions.(v) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> ()
| Dba.Instr.If (_, JInner target, fallthrough) ->
f target;
f fallthrough
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f fallthrough
let iter_pred f { predecessors; _ } v = List.iter f predecessors.(v)
let fold_succ f { instructions; _ } v x =
match instructions.(v) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> x
| Dba.Instr.If (_, JInner target, fallthrough) -> f target (f fallthrough x)
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f fallthrough x
let fold_pred f { predecessors; _ } v x =
List.fold_left (fun x src -> f src x) x predecessors.(v)
let iter_succ_e f { instructions; _ } v =
match instructions.(v) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> ()
| Dba.Instr.If (_, JInner target, fallthrough) ->
f (v, target);
f (v, fallthrough)
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f (v, fallthrough)
let fold_succ_e f { instructions; _ } v x =
match instructions.(v) with
| Dba.Instr.DJump _ | Dba.Instr.SJump (JOuter _, _) | Dba.Instr.Stop _ -> x
| Dba.Instr.If (_, JInner target, fallthrough) ->
f (v, target) (f (v, fallthrough) x)
| Dba.Instr.Assert (_, fallthrough)
| Dba.Instr.Assign (_, _, fallthrough)
| Dba.Instr.Assume (_, fallthrough)
| Dba.Instr.If (_, _, fallthrough)
| Dba.Instr.Nondet (_, fallthrough)
| Dba.Instr.SJump (JInner fallthrough, _)
| Dba.Instr.Undef (_, fallthrough) ->
f (v, fallthrough) x
let iter_pred_e f { predecessors; _ } v =
List.iter (fun src -> f (src, v)) predecessors.(v)
let fold_pred_e f { predecessors; _ } v x =
List.fold_left (fun x src -> f (src, v) x) x predecessors.(v)
end
module DI = Dba_types.Instruction
let stop_ok = Share.merge share (Dba.Instr.stop (Some Dba.OK))
let pred = G.pred
let succ = G.succ
let empty = G.empty
let stop = G.singleton stop_ok
let inst_exn { instructions; _ } n = instructions.(n)
let inst g n = try Some (inst_exn g n) with Invalid_argument _ -> None
let init = G.init
let singleton = G.singleton
let goto vaddr =
G.singleton (Share.merge share (Dba.Instr.static_outer_jump vaddr))
let unlink { instructions; predecessors; _ } i =
let n =
match Array.get instructions i with
| DJump _ | SJump (JOuter _, _) | Stop _ | If _ ->
raise (Invalid_argument "unlink")
| Assert (_, n)
| Assume (_, n)
| Assign (_, _, n)
| Nondet (_, n)
| SJump (JInner n, _)
| Undef (_, n) ->
n
in
if i = 0 then
Array.set instructions 0 (Share.merge share (Dba.Instr.static_inner_jump n))
else
let inner j = if j = i then n else j in
Array.set predecessors n
(List.fold_left
(fun ps p ->
Array.set instructions p
(Dba_types.Instruction.reloc ~inner (Array.get instructions p));
p :: ps)
(List.filter (( <> ) i) (Array.get predecessors n))
(Array.get predecessors i));
Array.set predecessors i [];
Array.set instructions i stop_ok
let length = G.nb_vertex
let is_empty = G.is_empty
let start _ = 0
let exits { exits; _ } = exits
let beginning_inst g = inst_exn g 0
let fold f acc { instructions; _ } = Array.fold_left f acc instructions
let of_list l =
let a = Array.of_list l in
init (Array.length a) (fun i -> a.(i))
let of_labelled_list l =
let a = Array.of_list l in
init (Array.length a) (fun i ->
let j, instr = a.(i) in
assert (i == j);
instr)
let flatten { instructions; _ } =
Array_utils.fold_righti
(fun i list instr -> (i, instr) :: list)
[] instructions
let to_list { instructions; _ } = Array.to_list instructions
let iteri ~f { instructions; _ } = Array.iteri f instructions
let iter ~f g = iteri ~f:(fun _ inst -> f inst) g
let copy { instructions; predecessors; exits } =
{
instructions = Array.copy instructions;
predecessors = Array.copy predecessors;
exits;
}
let mapi ~f { instructions; _ } =
init (Array.length instructions) (fun i -> f i instructions.(i))
exception Done
let for_all p g =
try
iter ~f:(fun i -> if not (p i) then raise_notrace Done) g;
true
with Done -> false
let pp ppf t =
let open Format in
fprintf ppf "@[<v 0>";
flatten t
|> List.iter (fun (addr, instr) ->
fprintf ppf "@[<h>%2d: %a@]@ " addr
(Dba_printer.Ascii.pp_instruction_maybe_goto ~current_id:addr)
instr);
fprintf ppf "@]"
let to_stmts t (address : Virtual_address.t) =
let base = Dba_types.Caddress.block_start address in
let l = to_list t in
List.mapi
(fun i e -> Dba_types.Statement.create (Dba_types.Caddress.reid base i) e)
l
let no_inner_reference instr = function
| Dba.JOuter _ -> true
| Dba.JInner _ as jt -> not (List.mem jt (DI.successors instr))
let _no_block_inner_references t n =
let jt = Dba.Jump_target.inner n in
for_all (fun instr -> no_inner_reference instr jt) t
let outer_jumps =
fold
(fun hwset instr ->
let jset = DI.outer_jumps instr in
Virtual_address.Set.union hwset jset)
Virtual_address.Set.empty
let callees =
fold
(fun hwset dinstr ->
let open Dba in
match dinstr with
| Instr.SJump (JOuter dst, Call _) ->
let a = Dba_types.Caddress.to_virtual_address dst in
Virtual_address.Set.add a hwset
| _ -> hwset)
Virtual_address.Set.empty
module Var = struct
include Dba.Var
let compare (t : t) (t' : t) = t.id - t'.id
module Set = struct
include Set.Make (struct
type nonrec t = t
let compare = compare
end)
let _pp ppf t =
if is_empty t then Format.pp_print_string ppf "{}"
else
let v = choose t in
let t = remove v t in
Format.pp_print_string ppf "{ ";
Format.pp_print_string ppf v.name;
iter
(fun v ->
Format.pp_print_string ppf ", ";
Format.pp_print_string ppf v.name)
t;
Format.pp_print_string ppf " }"
end
let rec collect (e : Dba.Expr.t) (d : Set.t) : Set.t =
match e with
| Cst _ -> d
| Var v -> Set.add v d
| Load (_, _, e, _) | Unary (_, e) -> collect e d
| Binary (_, e, e') -> collect e (collect e' d)
| Ite (e, e', e'') -> collect e (collect e' (collect e'' d))
let rec contains (v : t) (e : Dba.Expr.t) : bool =
match e with
| Cst _ -> false
| Var v' -> equal v v'
| Load (_, _, e, _) | Unary (_, e) -> contains v e
| Binary (_, e, e') -> contains v e || contains v e'
| Ite (e, e', e'') -> contains v e || contains v e' || contains v e''
module Map = Map.Make (struct
type nonrec t = t
let compare = compare
end)
end
module Int = Basic_types.Integers.Int
module Leader = Graph.Leaderlist.Make (G)
let optimize ?(inplace = false) t =
let t = if inplace then t else copy t in
let outs =
Var.Set.filter
(fun (var : Var.t) -> var.info <> Var.Tag.Temp)
(fold
(fun d (i : DI.t) ->
match i with
| Assign ((Var var | Restrict (var, _)), exp, _) ->
Var.(collect exp (Set.add var d))
| Assign (Store (_, _, addr, _), exp, _) ->
Var.(collect addr (collect exp d))
| Undef ((Var var | Restrict (var, _)), _)
| Nondet ((Var var | Restrict (var, _)), _) ->
Var.Set.add var d
| Undef (Store (_, _, addr, _), _) | Nondet (Store (_, _, addr, _), _)
->
Var.collect addr d
| Assume (exp, _) | Assert (exp, _) | If (exp, _, _) | DJump (exp, _)
->
Var.collect exp d
| SJump _ | Stop _ -> d)
Var.Set.empty t)
in
let module Analyze = struct
type data = Var.Set.t
type edge = G.E.t
type vertex = G.E.vertex
type g = G.t
let direction = Graph.Fixpoint.Backward
let join = Var.Set.union
let equal = Var.Set.equal
let analyze e d =
match inst_exn t (G.E.dst e) with
| Assign (Var var, exp, _) ->
if Var.Set.mem var d then Var.collect exp (Var.Set.remove var d)
else d
| Assign (Restrict (var, _), exp, _) ->
if Var.Set.mem var d then Var.collect exp d else d
| Assign (Store (_, _, addr, _), exp, _) ->
Var.(collect addr (collect exp d))
| Undef (Var var, _) | Nondet (Var var, _) -> Var.Set.remove var d
| Undef (Restrict _, _) | Nondet (Restrict _, _) -> d
| Undef (Store (_, _, addr, _), _) | Nondet (Store (_, _, addr, _), _) ->
Var.collect addr d
| Assume (exp, _) | Assert (exp, _) | If (exp, _, _) | DJump (exp, _) ->
Var.collect exp d
| SJump _ | Stop _ -> d
end in
let module Liveness = Graph.Fixpoint.Make (G) (Analyze) in
let liveness =
Liveness.analyze
(fun i ->
match inst_exn t i with
| DJump _ | SJump (JOuter _, _) | Stop _ | If (_, JOuter _, _) -> outs
| Assign _ | Undef _ | Nondet _ | Assume _ | Assert _ | If _ | SJump _
->
Var.Set.empty)
t
in
iteri
~f:(fun i (k : DI.t) ->
match k with
| Assign ((Var v | Restrict (v, _)), _, _)
| Undef ((Var v | Restrict (v, _)), _)
| Nondet ((Var v | Restrict (v, _)), _)
when Var.Set.mem v (liveness i) = false ->
unlink t i
| _ -> ())
t;
let rec associate o u i (e : Dba.Expr.t) =
match e with
| Cst _ -> u
| Var v -> (
try
let j = Var.Map.find v o in
if Int.Map.mem j u then Int.Map.add j None u
else Int.Map.add j (Some i) u
with Not_found -> u)
| Load (_, _, e, _) | Unary (_, e) -> associate o u i e
| Binary (_, e, e') -> associate o (associate o u i e) i e'
| Ite (e, e', e'') ->
associate o (associate o (associate o u i e) i e') i e''
in
List.iter
(fun block ->
let last = ref 0 in
let origin, use =
List.fold_left
(fun (o, u) i ->
last := i;
match inst_exn t i with
| Assign (Var var, exp, _) ->
(Var.Map.add var i o, associate o u i exp)
| Assign (Restrict (var, _), exp, _) ->
let o = Var.Map.remove var o
and u =
try
let j = Var.Map.find var o in
Int.Map.add j None u
with Not_found -> u
in
(o, Int.Map.add i None (associate o u i exp))
| Assign (Store (_, _, addr, _), exp, _) ->
(o, associate o (associate o u i addr) i exp)
| Undef (Var var, _) | Nondet (Var var, _) ->
(Var.Map.remove var o, u)
| Undef (Restrict (var, _), _) | Nondet (Restrict (var, _), _) ->
( Var.Map.remove var o,
try
let j = Var.Map.find var o in
Int.Map.add j None u
with Not_found -> u )
| Undef (Store (_, _, addr, _), _)
| Nondet (Store (_, _, addr, _), _) ->
(o, associate o u i addr)
| Assume (exp, _) | Assert (exp, _) | If (exp, _, _) | DJump (exp, _)
->
(o, associate o u i exp)
| SJump _ | Stop _ -> (o, u))
(Var.Map.empty, Int.Map.empty)
block
in
let use =
Var.Set.fold
(fun v u ->
try
let j = Var.Map.find v origin in
Int.Map.add j None u
with Not_found -> u)
(liveness !last) use
in
let rec subs_exp var value (e : Dba.Expr.t) =
match e with
| Cst _ -> e
| Var var' -> if Var.equal var var' then value else e
| Load (sz, en, e, array) ->
Dba.Expr.load (Size.Byte.create sz) en (subs_exp var value e) ?array
| Unary (f, e) -> Dba.Expr.unary f (subs_exp var value e)
| Binary (f, e, e') ->
Dba.Expr.binary f (subs_exp var value e) (subs_exp var value e')
| Ite (e, e', e'') ->
Dba.Expr.ite (subs_exp var value e) (subs_exp var value e')
(subs_exp var value e'')
in
let subs_lval var value (lv : Dba.LValue.t) =
match lv with
| Var _ -> lv
| Restrict _ -> lv
| Store (sz, en, addr, array) ->
Dba.LValue.store (Size.Byte.create sz) en (subs_exp var value addr)
?array
in
let rec contains_mem (e : Dba.Expr.t) =
match e with
| Cst _ -> false
| Var _ -> false
| Load _ -> true
| Unary (_, e) -> contains_mem e
| Binary (_, e, e') -> contains_mem e || contains_mem e'
| Ite (e, e', e'') ->
contains_mem e || contains_mem e' || contains_mem e''
in
Int.Map.iter
(fun o u ->
match u with
| None -> ()
| Some i -> (
match inst_exn t o with
| Assign (Var var, exp, n) ->
let mem_barrier = contains_mem exp in
let rec inline n =
if n = i then (
Array.set t.instructions i
(match inst_exn t n with
| Assign (lv, rv, n) ->
Dba.Instr.assign (subs_lval var exp lv)
(subs_exp var exp rv) n
| Undef (lv, n) ->
Dba.Instr.undefined (subs_lval var exp lv) n
| Nondet (lv, n) ->
Dba.Instr.non_deterministic (subs_lval var exp lv) n
| Assert (test, n) ->
Dba.Instr._assert (subs_exp var exp test) n
| Assume (test, n) ->
Dba.Instr.assume (subs_exp var exp test) n
| If (test, branch, n) ->
Dba.Instr.ite (subs_exp var exp test) branch n
| DJump (target, tag) ->
Dba.Instr.dynamic_jump (subs_exp var exp target)
~tag
| SJump _ | Stop _ -> assert false);
unlink t o)
else
match inst_exn t n with
| DJump _ | SJump (JOuter _, _) | Stop _ | If _ ->
assert false
| Assign ((Var var | Restrict (var, _)), _, n)
| Nondet ((Var var | Restrict (var, _)), n)
| Undef ((Var var | Restrict (var, _)), n) ->
if Var.contains var exp then () else inline n
| Assign (Store _, _, n)
| Nondet (Store _, n)
| Undef (Store _, n) ->
if not mem_barrier then inline n
| Assert (_, n) | Assume (_, n) | SJump (JInner n, _) ->
inline n
in
inline n
| _ -> assert false))
use)
(Leader.leader_lists t 0);
t
module Logger = Logger.Make (struct
let name = "hunk"
end)
let export_to_file g =
let filename = Filename.temp_file "dba" ".dot" in
Logger.debug ~level:4 "Exporting graph to file %s" filename;
let oc = open_out_bin filename in
let module C_dot = struct
include G
let graph_attributes _g = []
let default_vertex_attributes _ = [ `Shape `Box ]
let vertex_name v =
Format.asprintf "\"%d: %a\"" v Dba_printer.Ascii.pp_instruction
(inst_exn g v)
let vertex_attributes _v = []
let get_subgraph _ = None
let default_edge_attributes _ = []
let edge_attributes _ = []
end in
let module D = Graph.Graphviz.Dot (C_dot) in
D.output_graph oc g;
close_out oc;
filename
let view ~viewer filename =
let svg_filename = Filename.chop_extension filename ^ ".svg" in
Logger.debug ~level:4 "Exporting graph to SVG file %s" svg_filename;
let cmd = Printf.sprintf "dot -T svg %s > %s" filename svg_filename in
ignore (Sys.command cmd);
let view_cmd = Printf.sprintf "%s %s" viewer svg_filename in
ignore (Sys.command view_cmd)
let export_and_view ?(cmd = "firefox") g = export_to_file g |> view ~viewer:cmd
let is_return g =
let rec aux node =
let dinst = inst_exn g node in
DI.is_return dinst || match G.succ g node with [ v ] -> aux v | _ -> false
in
(not (G.is_empty g)) && aux 0
let has_indirect_jump { instructions; exits; _ } =
List.exists
(fun i ->
match instructions.(i) with Dba.Instr.DJump _ -> true | _ -> false)
exits
module Check = struct
let inner_jump_inside_bound t label = label >= 0 && label < length t
let get_inner_jumps =
let open Dba in
let aux acc = function
| Instr.SJump (JInner id, _) | Instr.If (_, JInner id, _) -> id :: acc
| Instr.If _ | Instr.SJump _ | Instr.DJump _ | Instr.Assign _
| Instr.Stop _ | Instr.Assert _ | Instr.Assume _ | Instr.Nondet _
| Instr.Undef _ ->
acc
in
fold aux []
let has_inbound_inner_jumps t =
get_inner_jumps t |> List.for_all (inner_jump_inside_bound t)
exception Undeclared_Variable of string * Dba.Instr.t
let no_undeclared_variables decls t =
let no_undeclared_at_instr i =
let du = DI.variables i in
let vset =
let open Dba_types in
Basic_types.String.Set.union du.uses du.defs
in
try
Basic_types.String.Set.iter
(fun vname ->
if not (Basic_types.String.Map.mem vname decls) then
raise (Undeclared_Variable (vname, i)))
vset;
true
with Undeclared_Variable (vname, instr) ->
Logger.fatal "Undeclared variable %s at instruction %a" vname
Dba_printer.Ascii.pp_instruction instr
in
for_all no_undeclared_at_instr t
exception Temporaries_undefined of Basic_types.String.Set.t * Dba.Instr.t
let no_temporary_leak g =
let module Strg = Basic_types.String in
let start = 0 in
let init v = (v = start, (DI.temporaries (inst_exn g v)).Dba_types.defs) in
let module N =
Graph.Fixpoint.Make
(G)
(struct
type g = G.t
type edge = G.E.t
type vertex = G.V.t
type data = bool * Basic_types.String.Set.t
let direction = Graph.Fixpoint.Forward
let join (r, s) (r', s') = (r || r', Basic_types.String.Set.union s s')
let equal (r, s) (r', s') =
r = r' && Basic_types.String.Set.equal s s'
let analyze e (r, s) =
let src = G.E.src e in
( r,
Basic_types.String.Set.union
(DI.temporaries (inst_exn g src)).Dba_types.defs s )
end)
in
let f = N.analyze init g in
Logger.debug ~level:6 "@[<v 0>%a@]"
(fun ppf g ->
G.iter_vertex
(fun v ->
Format.fprintf ppf "%d: %a [%a]@ " v
Dba_printer.Ascii.pp_instruction (inst_exn g v)
(fun ppf s ->
Strg.Set.iter (fun name -> Format.fprintf ppf "%s; " name) s)
(snd (f v)))
g)
g;
try
Array.iteri
(fun v inst ->
let reachable, defined = f v in
if not reachable then g.instructions.(v) <- stop.instructions.(0)
else
let du = DI.temporaries inst in
let undefined_temporaries =
Strg.Set.diff du.Dba_types.uses defined
in
if not (Strg.Set.is_empty undefined_temporaries) then
raise (Temporaries_undefined (undefined_temporaries, inst)))
g.instructions;
true
with Temporaries_undefined (tset, instr) ->
export_and_view g;
Logger.fatal
"@[<h>Temporaries %a were previously undefined but used at instruction \
%a@]"
(fun ppf set ->
Basic_types.String.Set.iter
(fun s -> Format.fprintf ppf "%s;@ " s)
set)
tset Dba_printer.Ascii.pp_instruction instr
end
type conditional = {
condition : Dba.Expr.t;
consequent : Virtual_address.t;
alternative : Virtual_address.t;
}
let conditional g =
if length g <> 2 then None
else
match beginning_inst g with
| Dba.Instr.If (condition, Dba.JOuter consequent, fallthrough) -> (
match inst_exn g fallthrough with
| Dba.Instr.SJump (Dba.JOuter alternative, _) ->
let open Dba_types.Caddress in
Some
{
condition;
consequent = to_virtual_address consequent;
alternative = to_virtual_address alternative;
}
| _ -> None)
| _ -> None
module Constant_propagation = struct
open Dba
module Env = struct
include Basic_types.String.Map
let eq = ( = )
let contains env1 env2 =
let mem vname cst =
match find vname env1 with
| v -> eq v cst
| exception Not_found -> false
in
for_all mem env2
let add vname cst env =
match find vname env with
| v -> if eq v cst then env else remove vname env
| exception Not_found -> add vname cst env
end
let rec eval_expr env = function
| Dba.Expr.Var v as e -> (
match Basic_types.String.Map.find v.name env with
| bv -> Expr.constant bv
| exception Not_found -> e)
| Dba.Expr.Load (sz, en, e, array) ->
let sz = Size.Byte.create sz in
Expr.load sz en (eval_expr env e) ?array
| Dba.Expr.Cst _ as e -> e
| Dba.Expr.Unary (uop, e) -> Expr.unary uop (eval_expr env e)
| Dba.Expr.Binary (bop, e1, e2) ->
Expr.binary bop (eval_expr env e1) (eval_expr env e2)
| Dba.Expr.Ite (c, e1, e2) ->
Expr.ite (eval_expr env c) (eval_expr env e1) (eval_expr env e2)
let eval_instruction penv i =
match i with
| Dba.Instr.Assign (lv, e, id) -> Instr.assign lv (eval_expr penv e) id
| Dba.Instr.DJump (e, tag) -> Instr.dynamic_jump ~tag (eval_expr penv e)
| Dba.Instr.If (c, jt, id) -> Instr.ite (eval_expr penv c) jt id
| Dba.Instr.Assert (c, id) -> Instr._assert (eval_expr penv c) id
| Dba.Instr.Assume (c, id) -> Instr.assume (eval_expr penv c) id
| ( Dba.Instr.Undef _ | Dba.Instr.Nondet _ | Dba.Instr.Stop _
| Dba.Instr.SJump _ ) as instr ->
instr
let gather_propagations ?(env = Env.empty) block =
let envs = to_list block |> List.map (fun _ -> None) |> Array.of_list in
let should_propagate env id =
match envs.(id) with
| None -> true
| Some e -> not (Env.contains env e)
in
let mark_env env idx = envs.(idx) <- Some env in
let remove lval env =
match Dba_types.LValue.name_of lval with
| Some vname -> Basic_types.String.Map.remove vname env
| None -> env
in
let rec loop env idx =
if should_propagate env idx then (
mark_env env idx;
match inst block idx with
| None -> env
| Some i -> (
match i with
| Dba.Instr.Assign (Dba.LValue.Var { name; _ }, Dba.Expr.Cst v, idx')
->
loop (Env.add name v env) idx'
| Dba.Instr.If (_, Dba.JInner idx1, idx2) ->
loop (loop env idx1) idx2
| Dba.Instr.Nondet (lv, id) -> loop (remove lv env) id
| Dba.Instr.Assert (_, id)
| Dba.Instr.Assume (_, id)
| Dba.Instr.Undef (_, id)
| Dba.Instr.Assign (_, _, id)
| Dba.Instr.SJump (Dba.JInner id, _)
| Dba.Instr.If (_, Dba.JOuter _, id) ->
loop env id
| Dba.Instr.SJump (Dba.JOuter _, _)
| Dba.Instr.DJump _ | Dba.Instr.Stop _ ->
env))
else env
in
ignore (loop env (start block));
envs
let do_propagations block propagation_envs =
mapi
~f:(fun i instruction ->
match propagation_envs.(i) with
| None -> instruction
| Some env ->
if Basic_types.String.Map.is_empty env then instruction
else eval_instruction env instruction)
block
let eval block =
Logger.debug ~level:5 "@[<v 0>Prepropagation@ %a@]" pp block;
let b = gather_propagations block |> do_propagations block in
Logger.debug ~level:5 "@[<v 0>Post-propagation@ %a@]" pp b;
b
end
let constant_propagation = Constant_propagation.eval
module DC_elimination = struct
module M = Basic_types.Integers.Int.Map
module S = Basic_types.Integers.Int.Set
let fetch target src p =
let alias = try src :: M.find src p with Not_found -> [ src ] in
try M.add target (List.append alias (M.find target p)) p
with Not_found -> M.add target alias p
let eval block =
let rec collect b n r m p w =
match S.min_elt w with
| exception Not_found -> (n, r, m)
| i when M.mem i m -> collect b n r m p (S.remove i w)
| i -> (
match inst_exn b i with
| Dba.Instr.SJump (Dba.JInner goto, _) ->
collect b n r m (fetch goto i p) S.(add goto (remove i w))
| inst ->
let m =
try List.fold_left (fun m i -> M.add i n m) m (M.find i p)
with Not_found -> m
in
collect b (n + 1) (M.add n i r) (M.add i n m) p
(List.fold_left
(fun w -> function
| Dba.JOuter _ -> w
| Dba.JInner id -> S.add id w)
(S.remove i w)
(Dba_types.Instruction.successors inst)))
in
let n, r, m = collect block 0 M.empty M.empty M.empty (S.singleton 0) in
let inner i = try M.find i m with Not_found -> i in
init n (fun i ->
Dba_types.Instruction.reloc ~inner (inst_exn block (M.find i r)))
end
let dead_code_elimination = DC_elimination.eval