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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.Reg.Set.t [@@deriving equal, sexp]
let pp = Llair.Reg.Set.pp
let report_fmt_thunk = Fun.flip pp
let empty = Llair.Reg.Set.empty
let init globals =
[%Trace.info "pgm globals: {%a}" (IArray.pp ", " Llair.Global.pp) globals] ;
empty
let join l r = Some (Llair.Reg.Set.union l r)
let recursion_beyond_bound = `skip
let is_false _ = false
let post _ _ state = state
let retn _ _ from_call post = Llair.Reg.Set.union from_call post
let dnf t = [t]
let add_if_global v gs =
if Llair.Reg.is_global v then Llair.Reg.Set.add v gs else gs
let used_globals exp s = Llair.Exp.fold_regs ~f:add_if_global exp 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]
;
Some (Llair.Inst.fold_exps ~f:used_globals inst st)
|>
[%Trace.retn fun {pf} ->
Option.iter ~f:(fun uses -> pf "post:{%a}" pp uses)]
let exec_intrinsic ~skip_throw:_ _ intrinsic actuals st =
let name = Llair.Reg.name intrinsic in
if
List.exists
[ "malloc"
; "aligned_alloc"
; "calloc"
; "posix_memalign"
; "realloc"
; "mallocx"
; "rallocx"
; "xallocx"
; "sallocx"
; "dallocx"
; "sdallocx"
; "nallocx"
; "malloc_usable_size"
; "mallctl"
; "mallctlnametomib"
; "mallctlbymib"
; "malloc_stats_print"
; "strlen"
; "__cxa_allocate_exception"
; "_ZN5folly13usingJEMallocEv" ]
~f:(String.equal name)
then List.fold ~f:used_globals actuals st |> fun res -> Some (Some res)
else None
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, List.fold ~f:used_globals actuals st)
let resolve_callee lookup ptr st =
let st = used_globals ptr st in
match Llair.Reg.of_exp ptr with
| Some callee -> (lookup (Llair.Reg.name callee), st)
| None -> ([], st)
(* 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.Reg.Set.union st summ)
(** Query *)
type r =
| Per_function of Llair.Reg.Set.t Llair.Reg.Map.t
| Declared of Llair.Reg.Set.t
let by_function : r -> Llair.Reg.t -> t =
fun s fn ->
[%Trace.call fun {pf} -> pf "%a" Llair.Reg.pp fn]
;
( match s with
| Declared set -> set
| Per_function map -> (
match Llair.Reg.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.Reg.pp fn () ) )
|>
[%Trace.retn fun {pf} r -> pf "%a" Llair.Reg.Set.pp r]