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|
(* Js_of_ocaml compiler
* http://www.ocsigen.org/js_of_ocaml/
* Copyright (C) 2010 Jérôme Vouillon
* Laboratoire PPS - CNRS Université Paris Diderot
*
* 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 Code
(****)
let pure_expr pure_funs e =
match e with
Const _ | Block _ | Field _ | Closure _ | Constant _ ->
true
| Apply (f, l, exact) ->
exact && VarSet.mem f pure_funs
| Prim (p, l) ->
match p with
Extern f -> Primitive.is_pure f
| _ -> true
let pure_instr pure_funs i =
match i with
Let (_, e) ->
pure_expr pure_funs e
| Set_field _ | Offset_ref _ | Array_set _ ->
false
(****)
let rec traverse blocks pc visited funs =
try
(AddrMap.find pc visited, visited, funs)
with Not_found ->
let visited = AddrMap.add pc false visited in
let (pure, visited, funs) =
fold_children blocks pc
(fun pc (pure, visited, funs) ->
let (pure', visited, funs) = traverse blocks pc visited funs in
(pure && pure', visited, funs))
(true, visited, funs)
in
let (pure, visited, funs) = block blocks pc pure visited funs in
(pure, AddrMap.add pc pure visited, funs)
and block blocks pc pure visited funs =
let b = AddrMap.find pc blocks in
let pure = match b.branch with Raise _ -> false | _ -> pure in
List.fold_left
(fun (pure, visited, funs) i ->
let (visited, funs) =
match i with
Let (x, Closure (_, (pc, _))) ->
let (pure, visited, funs) = traverse blocks pc visited funs in
(visited, if pure then VarSet.add x funs else funs)
| _ ->
(visited, funs)
in
(pure && pure_instr funs i, visited, funs))
(pure, visited, funs) b.body
let f (pc, blocks, _) =
let (_, _, funs) = traverse blocks pc AddrMap.empty VarSet.empty in
funs
|
