Source file generic_decoder.ml
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open Generic_decoder_sig
module Decode_Expr (I : Expr_Input) = struct
open Dba
open Binary_op
open I
let ( >>= ) = M.bind
let rec expr : Dba.Expr.t -> I.binary M.m =
fun e ->
match e with
| Expr.Cst bv ->
let size = Bitvector.size_of bv in
I.Binary.biconst ~size (Bitvector.value_of bv)
| Expr.Binary (bop, e1, e2) -> (
let size = Dba.Expr.size_of e1 in
expr e1 >>= fun v1 ->
expr e2 >>= fun v2 ->
match bop with
| Plus -> I.Binary.biadd ~size v1 v2
| Minus -> I.Binary.bisub ~size v1 v2
| Mult -> I.Binary.bimul ~size v1 v2
| DivU -> I.Binary.biudiv ~size v1 v2
| DivS -> I.Binary.bisdiv ~size v1 v2
| RemU -> I.Binary.biurem ~size v1 v2
| RemS -> I.Binary.bisrem ~size v1 v2
| Or -> I.Binary.bor ~size v1 v2
| And -> I.Binary.band ~size v1 v2
| Xor -> I.Binary.bxor ~size v1 v2
| Concat ->
I.Binary.bconcat ~size1:(Dba.Expr.size_of e1) v1
~size2:(Dba.Expr.size_of e2) v2
| LShift -> I.Binary.bshl ~size v1 v2
| RShiftU -> I.Binary.blshr ~size v1 v2
| RShiftS -> I.Binary.bashr ~size v1 v2
| LeftRotate -> I.Binary.bv_left_rotate ~size v1 v2
| RightRotate -> I.Binary.bv_right_rotate ~size v1 v2
| Eq -> I.Binary.beq ~size v1 v2 >>= fun bool -> I.bin_of_bool bool
| Diff ->
I.Binary.beq ~size v1 v2 >>= fun bool ->
I.Boolean.not bool >>= fun nbool -> I.bin_of_bool nbool
| LeqU -> I.Binary.biule ~size v1 v2 >>= fun bool -> I.bin_of_bool bool
| GeqU -> I.Binary.biule ~size v2 v1 >>= fun bool -> I.bin_of_bool bool
| LeqS -> I.Binary.bisle ~size v1 v2 >>= fun bool -> I.bin_of_bool bool
| GeqS -> I.Binary.bisle ~size v2 v1 >>= fun bool -> I.bin_of_bool bool
| LtU -> I.Binary.biult ~size v1 v2 >>= fun bool -> I.bin_of_bool bool
| GtU -> I.Binary.biult ~size v2 v1 >>= fun bool -> I.bin_of_bool bool
| LtS -> I.Binary.bislt ~size v1 v2 >>= fun bool -> I.bin_of_bool bool
| GtS -> I.Binary.bislt ~size v2 v1 >>= fun bool -> I.bin_of_bool bool)
| Expr.Unary (op, e1) as e -> (
let size = Dba.Expr.size_of e in
expr e1 >>= fun v1 ->
match op with
| Unary_op.UMinus ->
I.Binary.biconst ~size Z.zero >>= fun vz ->
I.Binary.bisub ~size vz v1
| Unary_op.Not ->
I.Binary.biconst ~size Z.minus_one >>= fun ffff ->
I.Binary.bxor ~size ffff v1
| Unary_op.Uext n ->
I.Binary.buext ~size:n ~oldsize:(Dba.Expr.size_of e1) v1
| Unary_op.Sext n ->
I.Binary.bsext ~size:n ~oldsize:(Dba.Expr.size_of e1) v1
| Unary_op.Restrict { Interval.lo; Interval.hi } ->
I.Binary.bextract ~lo ~hi ~oldsize:(Dba.Expr.size_of e1) v1)
| Expr.Var { name = var; size; _ } -> I.get_var ~size var
| Expr.Load (size, endianness, e, None) ->
expr e >>= fun address -> I.load ~size:(size * 8) endianness address
| Expr.Load _ -> assert false
| Expr.Ite (c, e1, e2) ->
cond c >>= fun vc ->
expr e1 >>= fun v1 ->
expr e2 >>= fun v2 -> I.ite vc v1 v2
and cond : Dba.Expr.t -> I.boolean M.m =
fun e ->
assert (Dba.Expr.size_of e == 1);
let open Dba.Expr in
match e with
| Cst x when Bitvector.is_one x -> I.Boolean.true_
| Cst x when Bitvector.is_zero x -> I.Boolean.false_
| Cst _ -> assert false
| Unary (Unary_op.Not, x) -> cond x >>= fun v -> I.Boolean.not v
| Unary (Unary_op.UMinus, x) -> cond x
| Binary (And, a, b) ->
cond a >>= fun va ->
cond b >>= fun vb -> I.Boolean.( && ) va vb
| Binary (Or, a, b) ->
cond a >>= fun va ->
cond b >>= fun vb -> I.Boolean.( || ) va vb
| e -> expr e >>= fun v -> I.bool_of_bin v
end
module Decode_Instr (S : Instr_Input) : sig
val instruction :
S.State.t ->
Dba.Instr.t ->
(S.boolean, S.binary) Generic_decoder_sig.jump_kind * S.State.t
end = struct
module EDecode = Decode_Expr (struct
include S
module M = State_Monad (S.State)
end)
open Dba
let write_lhs state value = function
| LValue.Var { name; size; _ } -> S.set_var ~size name value state
| LValue.Restrict ({ name; size; _ }, { Interval.lo; Interval.hi }) ->
let value_size = size in
let old, state = S.get_var ~size name state in
let written_size = 1 + hi - lo in
let v, state =
if lo == 0 then (value, state)
else
let pold, state =
S.Binary.bextract ~oldsize:value_size ~lo:0 ~hi:(lo - 1) old state
in
S.Binary.bconcat ~size1:written_size ~size2:lo value pold state
in
let v, state =
if hi == size - 1 then (v, state)
else
let pold, state =
S.Binary.bextract ~oldsize:value_size ~lo:(hi + 1) ~hi:(size - 1)
old state
in
S.Binary.bconcat ~size1:(size - hi) ~size2:hi pold v state
in
S.set_var ~size name v state
| LValue.Store (size, endianness, address, None) ->
let vaddress, state = EDecode.expr address state in
S.store ~size:(size * 8) endianness vaddress value state
| LValue.Store _ -> assert false
let instruction state instr =
let open! Generic_decoder_sig in
let open Instr in
match instr with
| Assign (lhs, expr, id) ->
let v, state = EDecode.expr expr state in
let state = write_lhs state v lhs in
(JKJump (Static (JInner id)), state)
| SJump (target, _) -> (JKJump (Static target), state)
| DJump (target, _) ->
let v, state = EDecode.expr target state in
(JKJump (Dynamic v), state)
| If (Dba.Expr.Cst bv, target, id) ->
if Bitvector.is_one bv then (JKJump (Static target), state)
else (JKJump (Static (JInner id)), state)
| If (cond, target, id) ->
let v, state = EDecode.cond cond state in
(JKIf (v, Static target, Static (JInner id)), state)
| Stop _ -> (JKStop, state)
| Assume (cond, id) | Assert (cond, id) ->
let v, state = EDecode.cond cond state in
(JKAssume (v, Static (JInner id)), state)
| Nondet (lhs, id) ->
let size = assert false in
let v, state = S.unknown ~size state in
let state = write_lhs state v lhs in
(JKJump (Static (JInner id)), state)
| Undef (lhs, id) ->
let size = Dba_types.LValue.unsafe_bitsize lhs in
let v, state = S.undef ~size state in
let state = write_lhs state v lhs in
(JKJump (Static (JInner id)), state)
end