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|
(* Wasm_of_ocaml compiler
* http://www.ocsigen.org/js_of_ocaml/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, with linking exception;
* either version 2.1 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*)
open! Stdlib
open Code
type closure =
{ functions : (Var.t * int) list
; free_variables : Var.t list
; mutable id : int option
}
module SCC = Strongly_connected_components.Make (Var)
let iter_closures ~f instrs =
let rec iter_closures_rec f instr_acc clos_acc instrs =
let push_closures clos_acc instr_acc =
if Var.Map.is_empty clos_acc
then instr_acc
else
let l = f clos_acc in
List.rev_map
~f:(fun g ->
let params, cont, cloc = Var.Map.find g clos_acc in
Let (g, Closure (params, cont, cloc)))
l
@ instr_acc
in
match instrs with
| [] -> List.rev (push_closures clos_acc instr_acc)
| Let (g, Closure (params, cont, cloc)) :: rem ->
iter_closures_rec f instr_acc (Var.Map.add g (params, cont, cloc) clos_acc) rem
| i :: rem ->
iter_closures_rec f (i :: push_closures clos_acc instr_acc) Var.Map.empty rem
in
iter_closures_rec f [] Var.Map.empty instrs
let collect_free_vars program var_depth depth pc closures =
let vars = ref Var.Set.empty in
let add_if_free_variable x =
let idx = Var.idx x in
let d = var_depth.(idx) in
assert (d >= 0);
if d < depth then vars := Var.Set.add x !vars
in
Code.preorder_traverse
{ fold = Code.fold_children }
(fun pc () ->
let block = Code.Addr.Map.find pc program.blocks in
Freevars.iter_block_free_vars add_if_free_variable block;
List.iter block.body ~f:(fun i ->
match i with
| Let (f, Closure _) -> (
match Var.Map.find_opt f closures with
| Some { functions = (g, _) :: _; free_variables; _ } when Var.equal f g ->
List.iter ~f:add_if_free_variable free_variables
| Some _ | None -> ())
| _ -> ()))
pc
program.blocks
();
!vars
let mark_bound_variables var_depth block depth =
Freevars.iter_block_bound_vars (fun x -> var_depth.(Var.idx x) <- depth) block;
List.iter block.body ~f:(fun i ->
match i with
| Let (_, Closure (params, _, _)) ->
List.iter params ~f:(fun x -> var_depth.(Var.idx x) <- depth + 1)
| _ -> ())
let rec traverse var_depth closures program pc depth =
Code.preorder_traverse
{ fold = Code.fold_children }
(fun pc (program : Code.program) ->
let block = Code.Addr.Map.find pc program.blocks in
mark_bound_variables var_depth block depth;
let program =
List.fold_left
~f:(fun program i ->
match i with
| Let (_, Closure (_, (pc', _), _)) ->
traverse var_depth closures program pc' (depth + 1)
| _ -> program)
~init:program
block.body
in
let body =
iter_closures block.body ~f:(fun l ->
let free_vars =
Var.Map.fold
(fun f (_, (pc', _), _) free_vars ->
Var.Map.add
f
(collect_free_vars program var_depth (depth + 1) pc' !closures)
free_vars)
l
Var.Map.empty
in
let domain = Var.Map.fold (fun f _ s -> Var.Set.add f s) l Var.Set.empty in
let graph = Var.Map.map (fun s -> Var.Set.inter s domain) free_vars in
let components = SCC.connected_components_sorted_from_roots_to_leaf graph in
let l =
Array.map
~f:(fun component ->
let fun_lst =
match component with
| SCC.No_loop x -> [ x ]
| SCC.Has_loop l -> l
in
let free_variables =
Var.Set.elements
(List.fold_left
~f:(fun fv x -> Var.Set.remove x fv)
~init:
(List.fold_left
~f:(fun fv x -> Var.Set.union fv (Var.Map.find x free_vars))
~init:Var.Set.empty
fun_lst)
fun_lst)
in
let functions =
let arities =
Var.Map.fold
(fun f (params, _, _) m -> Var.Map.add f (List.length params) m)
l
Var.Map.empty
in
List.map ~f:(fun f -> f, Var.Map.find f arities) fun_lst
in
List.iter
~f:(fun (f, _) ->
closures :=
Var.Map.add f { functions; free_variables; id = None } !closures)
functions;
fun_lst)
components
in
List.concat (List.rev (Array.to_list l)))
in
{ program with blocks = Code.Addr.Map.add pc { block with body } program.blocks })
pc
program.blocks
program
let f p =
let t = Timer.make () in
let nv = Var.count () in
let var_depth = Array.make nv (-1) in
let closures = ref Var.Map.empty in
let p = traverse var_depth closures p p.start 0 in
if Debug.find "times" () then Format.eprintf " closure conversion: %a@." Timer.print t;
p, !closures
|
