catala/compiler/lcalc/optimizations.ml
2021-11-30 16:27:47 +01:00

93 lines
4.1 KiB
OCaml

(* This file is part of the Catala compiler, a specification language for tax and social benefits
computation rules. Copyright (C) 2020 Inria, contributor: Denis Merigoux
<denis.merigoux@inria.fr>
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License
is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
or implied. See the License for the specific language governing permissions and limitations under
the License. *)
open Utils
open Ast
let ( let+ ) x f = Bindlib.box_apply f x
let ( and+ ) x y = Bindlib.box_pair x y
let transform (t : 'a -> expr Pos.marked -> expr Pos.marked Bindlib.box) (ctx : 'a)
(e : expr Pos.marked) : expr Pos.marked Bindlib.box =
(* calls [t ctx] on every direct childs of [e], then rebuild an abstract syntax tree modified.
Used in other transformations. *)
let default_mark e' = Pos.mark (Pos.get_position e) e' in
match Pos.unmark e with
| EVar (v, pos) ->
let+ v = Bindlib.box_var v in
(v, pos)
| ETuple (args, n) ->
let+ args = args |> List.map (t ctx) |> Bindlib.box_list in
default_mark @@ ETuple (args, n)
| ETupleAccess (e1, i, n, ts) ->
let+ e1 = t ctx e1 in
default_mark @@ ETupleAccess (e1, i, n, ts)
| EInj (e1, i, n, ts) ->
let+ e1 = t ctx e1 in
default_mark @@ EInj (e1, i, n, ts)
| EMatch (arg, cases, n) ->
let+ arg = t ctx arg and+ cases = cases |> List.map (t ctx) |> Bindlib.box_list in
default_mark @@ EMatch (arg, cases, n)
| EArray args ->
let+ args = args |> List.map (t ctx) |> Bindlib.box_list in
default_mark @@ EArray args
| EAbs ((binder, pos_binder), ts) ->
let vars, body = Bindlib.unmbind binder in
let body = t ctx body in
let+ binder = Bindlib.bind_mvar vars body in
default_mark @@ EAbs ((binder, pos_binder), ts)
| EApp (e1, args) ->
let+ e1 = t ctx e1 and+ args = args |> List.map (t ctx) |> Bindlib.box_list in
default_mark @@ EApp (e1, args)
| EAssert e1 ->
let+ e1 = t ctx e1 in
default_mark @@ EAssert e1
| EIfThenElse (e1, e2, e3) ->
let+ e1 = t ctx e1 and+ e2 = t ctx e2 and+ e3 = t ctx e3 in
default_mark @@ EIfThenElse (e1, e2, e3)
| ECatch (e1, exn, e2) ->
let+ e1 = t ctx e1 and+ e2 = t ctx e2 in
default_mark @@ ECatch (e1, exn, e2)
| ERaise _ | ELit _ | EOp _ -> Bindlib.box e
let rec iota_expr (_ : unit) (e : expr Pos.marked) : expr Pos.marked Bindlib.box =
let default_mark e' = Pos.mark (Pos.get_position e) e' in
match Pos.unmark e with
| EMatch ((EInj (e1, i, n', _ts), _), cases, n) when Dcalc.Ast.EnumName.compare n n' = 0 ->
let+ e1 = transform iota_expr () e1 and+ case = transform iota_expr () (List.nth cases i) in
default_mark @@ EApp (case, [ e1 ])
| _ -> transform iota_expr () e
let iota_optimizations (p : program) : program =
{ p with scopes = List.map (fun (var, e) -> (var, Bindlib.unbox (iota_expr () e))) p.scopes }
let rec peephole_expr (_ : unit) (e : expr Pos.marked) : expr Pos.marked Bindlib.box =
let default_mark e' = Pos.mark (Pos.get_position e) e' in
match Pos.unmark e with
| EIfThenElse (e1, e2, e3) -> (
let+ e1 = transform peephole_expr () e1
and+ e2 = transform peephole_expr () e2
and+ e3 = transform peephole_expr () e3 in
match Pos.unmark e1 with
| ELit (LBool true) | EApp ((EOp (Unop (Log _)), _), [ (ELit (LBool true), _) ]) -> e2
| ELit (LBool false) | EApp ((EOp (Unop (Log _)), _), [ (ELit (LBool false), _) ]) -> e3
| _ -> default_mark @@ EIfThenElse (e1, e2, e3))
| _ -> transform peephole_expr () e
let peephole_optimizations (p : program) : program =
{ p with scopes = List.map (fun (var, e) -> (var, Bindlib.unbox (peephole_expr () e))) p.scopes }
let optimize_program (p : program) : program = p |> iota_optimizations |> peephole_optimizations