ocaml/middle_end/effect_analysis.ml

61 lines
2.8 KiB
OCaml

(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Pierre Chambart, OCamlPro *)
(* Mark Shinwell and Leo White, Jane Street Europe *)
(* *)
(* Copyright 2013--2016 OCamlPro SAS *)
(* Copyright 2014--2016 Jane Street Group LLC *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
[@@@ocaml.warning "+a-4-9-30-40-41-42"]
open! Int_replace_polymorphic_compare
let no_effects_prim (prim : Lambda.primitive) =
match Semantics_of_primitives.for_primitive prim with
| (No_effects | Only_generative_effects), (No_coeffects | Has_coeffects) ->
true
| _ -> false
let rec no_effects (flam : Flambda.t) =
match flam with
| Var _ -> true
| Let { defining_expr; body; _ } ->
no_effects_named defining_expr && no_effects body
| Let_mutable { body } -> no_effects body
| Let_rec (defs, body) ->
no_effects body
&& List.for_all (fun (_, def) -> no_effects_named def) defs
| If_then_else (_, ifso, ifnot) -> no_effects ifso && no_effects ifnot
| Switch (_, sw) ->
let aux (_, flam) = no_effects flam in
List.for_all aux sw.blocks
&& List.for_all aux sw.consts
&& Misc.Stdlib.Option.value_default no_effects sw.failaction
~default:true
| String_switch (_, sw, def) ->
List.for_all (fun (_, lam) -> no_effects lam) sw
&& Misc.Stdlib.Option.value_default no_effects def
~default:true
| Static_catch (_, _, body, _) | Try_with (body, _, _) ->
(* If there is a [raise] in [body], the whole [Try_with] may have an
effect, so there is no need to test the handler. *)
no_effects body
| While _ | For _ | Apply _ | Send _ | Assign _ | Static_raise _ -> false
| Proved_unreachable -> true
and no_effects_named (named : Flambda.named) =
match named with
| Symbol _ | Const _ | Allocated_const _ | Read_mutable _
| Read_symbol_field _
| Set_of_closures _ | Project_closure _ | Project_var _
| Move_within_set_of_closures _ -> true
| Prim (prim, _, _) -> no_effects_prim prim
| Expr flam -> no_effects flam