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(*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*)
(** Used-globals abstract domain *)
type t = Llair.Global.Set.t [@@deriving compare, equal, sexp]
let pp = Llair.Global.Set.pp
let empty = Llair.Global.Set.empty
let init globals =
[%Trace.info
" globals: {%a}" (IArray.pp ", " Llair.GlobalDefn.pp) globals] ;
empty
let join l r = Llair.Global.Set.union l r
let recursion_beyond_bound = `skip
let post _ _ state = state
let retn _ _ from_call post = Llair.Global.Set.union from_call post
let dnf t = [t]
let used_globals exp s =
Llair.Exp.fold_exps exp s ~f:(fun e s ->
match Llair.Global.of_exp e with
| Some g -> Llair.Global.Set.add g s
| None -> s )
let exec_assume st exp = Some (used_globals exp st)
let exec_kill _ st = st
let exec_move reg_exps st =
IArray.fold ~f:(fun (_, rhs) -> used_globals rhs) reg_exps st
let exec_inst inst st =
[%Trace.call fun {pf} -> pf "@ pre:{%a} %a" pp st Llair.Inst.pp inst]
;
Ok (Llair.Inst.fold_exps ~f:used_globals inst st)
|>
[%Trace.retn fun {pf} ->
Or_alarm.iter ~f:(fun uses -> pf "post:{%a}" pp uses)]
type from_call = t [@@deriving sexp]
(* Set abstract state to bottom (i.e. empty set) at function entry *)
let call ~summaries:_ ~globals:_ ~actuals ~areturn:_ ~formals:_ ~freturn:_
~locals:_ st =
(empty, IArray.fold ~f:used_globals actuals st)
let resolve_callee _ _ _ = []
(* A function summary is the set of global registers accessed by that
function and its transitive callees *)
type summary = t
let pp_summary = pp
let create_summary ~locals:_ ~formals:_ state = (state, state)
let apply_summary st summ = Some (Llair.Global.Set.union st summ)
(** Query *)
type used_globals =
| Per_function of summary Llair.Function.Map.t
| Declared of summary
let by_function : used_globals -> Llair.Function.t -> t =
fun s fn ->
[%Trace.call fun {pf} -> pf "@ %a" Llair.Function.pp fn]
;
( match s with
| Declared set -> set
| Per_function map -> (
match Llair.Function.Map.find fn map with
| Some gs -> gs
| None ->
fail
"main analysis reached function %a that was not reached by \
used-globals pre-analysis "
Llair.Function.pp fn () ) )
|>
[%Trace.retn fun {pf} r -> pf "%a" Llair.Global.Set.pp r]