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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! Stdlib
open Code
type prop =
{ size : int
; optimizable : bool
}
type closure_info =
{ cl_params : Var.t list
; cl_cont : int * Var.t list
; cl_prop : prop
; cl_simpl : (Var.Set.t * int Var.Map.t * bool * Var.Set.t) option
}
let block_size { branch; body; _ } =
List.fold_left
~f:(fun n i ->
match i with
| Event _ -> n
| _ -> n + 1)
~init:0
body
+
match branch with
| Cond _ -> 2
| Switch (_, a1) -> Array.length a1
| _ -> 0
let simple_function blocks size name params pc =
let bound_vars =
ref (List.fold_left ~f:(fun s x -> Var.Set.add x s) ~init:Var.Set.empty params)
in
let free_vars = ref Var.Map.empty in
let tc = ref Var.Set.empty in
try
(* Ignore large functions *)
if size > 10 then raise Exit;
Code.preorder_traverse
{ fold = Code.fold_children }
(fun pc () ->
let block = Addr.Map.find pc blocks in
(match block.branch with
(* We currenly disable inlining when raising and catching exception *)
| Poptrap _ | Pushtrap _ -> raise Exit
| Raise _ -> raise Exit
| Stop -> raise Exit
| Return x -> (
match List.last block.body with
| None -> ()
| Some (Let (y, Apply { f; _ })) ->
(* track if some params are called in tail position *)
if Code.Var.equal x y && List.mem f ~set:params
then tc := Var.Set.add f !tc
| Some _ -> ())
| Branch _ | Cond _ | Switch _ -> ());
List.iter block.body ~f:(fun i ->
match i with
(* We currenly don't want to duplicate Closure *)
| Let (_, Closure _) -> raise Exit
| _ -> ());
Freevars.iter_block_bound_vars
(fun x -> bound_vars := Var.Set.add x !bound_vars)
block;
Freevars.iter_block_free_vars
(fun x ->
if not (Var.Set.mem x !bound_vars)
then
free_vars :=
Var.Map.update
x
(function
| None -> Some 1
| Some n -> Some (succ n))
!free_vars)
block)
pc
blocks
();
Some (!bound_vars, !free_vars, Var.Map.mem name !free_vars, !tc)
with Exit -> None
(****)
let optimizable blocks pc =
Code.traverse
{ fold = Code.fold_children }
(fun pc { size; optimizable } ->
let b = Addr.Map.find pc blocks in
let this_size = block_size b in
let optimizable =
optimizable
&& List.for_all b.body ~f:(function
| Let (_, Prim (Extern "caml_js_eval_string", _)) -> false
| Let (_, Prim (Extern "debugger", _)) -> false
| Let
( _
, Prim
(Extern ("caml_js_var" | "caml_js_expr" | "caml_pure_js_expr"), _)
) ->
(* TODO: we should be smarter here and look the generated js *)
(* let's consider it this opmiziable *)
true
| _ -> true)
in
{ optimizable; size = size + this_size })
pc
blocks
{ optimizable = true; size = 0 }
let get_closures { blocks; _ } =
Addr.Map.fold
(fun _ block closures ->
List.fold_left block.body ~init:closures ~f:(fun closures i ->
match i with
| Let (x, Closure (cl_params, cl_cont)) ->
(* we can compute this once during the pass
as the property won't change with inlining *)
let cl_prop = optimizable blocks (fst cl_cont) in
let cl_simpl =
simple_function blocks cl_prop.size x cl_params (fst cl_cont)
in
Var.Map.add x { cl_params; cl_cont; cl_prop; cl_simpl } closures
| _ -> closures))
blocks
Var.Map.empty
(****)
let rewrite_block pc' pc blocks =
let block = Addr.Map.find pc blocks in
let block =
match block.branch, pc' with
| Return y, Some pc' -> { block with branch = Branch (pc', [ y ]) }
| _ -> block
in
Addr.Map.add pc block blocks
let rewrite_closure blocks cont_pc clos_pc =
Code.traverse
{ fold = Code.fold_children_skip_try_body }
(rewrite_block cont_pc)
clos_pc
blocks
blocks
(****)
let rec args_equal xs ys =
match xs, ys with
| [], [] -> true
| x :: xs, Pv y :: ys -> Code.Var.compare x y = 0 && args_equal xs ys
| _ -> false
let inline ~first_class_primitives live_vars closures name pc (outer, p) =
let block = Addr.Map.find pc p.blocks in
let body, (outer, branch, p) =
List.fold_right
block.body
~init:([], (outer, block.branch, p))
~f:(fun i (rem, state) ->
match i with
| Let (x, Apply { f; args; exact = true; _ }) when Var.Map.mem f closures -> (
let outer, branch, p = state in
let { cl_params = params
; cl_cont = clos_cont
; cl_prop = { size = f_size; optimizable = f_optimizable }
; cl_simpl
} =
Var.Map.find f closures
in
let map_param_to_arg =
List.fold_left2
~f:(fun map a b -> Var.Map.add a b map)
~init:Var.Map.empty
params
args
in
if live_vars.(Var.idx f) = 1
&& Bool.equal outer.optimizable f_optimizable
(* Inlining the code of an optimizable function could
make this code unoptimized. (wrt to Jit compilers) *)
&& f_size < Config.Param.inlining_limit ()
then
let blocks, cont_pc, free_pc =
match rem, branch with
| [], Return y when Var.compare x y = 0 ->
(* We do not need a continuation block for tail calls *)
p.blocks, None, p.free_pc
| _ ->
let fresh_addr = p.free_pc in
let free_pc = fresh_addr + 1 in
( Addr.Map.add
fresh_addr
{ params = [ x ]; body = rem; branch }
p.blocks
, Some fresh_addr
, free_pc )
in
let blocks = rewrite_closure blocks cont_pc (fst clos_cont) in
(* We do not really need this intermediate block.
It just avoids the need to find which function
parameters are used in the function body. *)
let fresh_addr = free_pc in
let free_pc = fresh_addr + 1 in
let blocks =
Addr.Map.add
fresh_addr
{ params; body = []; branch = Branch clos_cont }
blocks
in
let outer = { outer with size = outer.size + f_size } in
[], (outer, Branch (fresh_addr, args), { p with blocks; free_pc })
else
match cl_simpl with
| Some (bound_vars, free_vars, recursive, tc_params)
(* We inline/duplicate
- single instruction functions (f_size = 1)
- small funtions that call one of their arguments in
tail position when the argument is a direct closure
used only once. *)
when (Code.Var.Set.exists
(fun x ->
let farg_tc = Var.Map.find x map_param_to_arg in
Var.Map.mem farg_tc closures && live_vars.(Var.idx farg_tc) = 1)
tc_params
|| f_size <= 1)
&& ((not recursive)
||
match name with
| None -> true
| Some f' -> not (Var.equal f f')) ->
let () =
(* Update live_vars *)
Var.Map.iter
(fun fv c ->
if not (Var.equal fv f)
then
let idx = Var.idx fv in
live_vars.(idx) <- live_vars.(idx) + c)
free_vars;
live_vars.(Var.idx f) <- live_vars.(Var.idx f) - 1
in
let p, f, params, clos_cont =
let bound_vars = Var.Set.add f bound_vars in
Duplicate.closure p ~bound_vars ~f ~params ~cont:clos_cont
in
if recursive
then
( Let (f, Closure (params, clos_cont))
:: Let (x, Apply { f; args; exact = true })
:: rem
, (outer, branch, p) )
else
let blocks, cont_pc, free_pc =
match rem, branch with
| [], Return y when Var.compare x y = 0 ->
(* We do not need a continuation block for tail calls *)
p.blocks, None, p.free_pc
| _ ->
let fresh_addr = p.free_pc in
let free_pc = fresh_addr + 1 in
( Addr.Map.add
fresh_addr
{ params = [ x ]; body = rem; branch }
p.blocks
, Some fresh_addr
, free_pc )
in
let blocks = rewrite_closure blocks cont_pc (fst clos_cont) in
(* We do not really need this intermediate block.
It just avoids the need to find which function
parameters are used in the function body. *)
let fresh_addr = free_pc in
let free_pc = fresh_addr + 1 in
let blocks =
Addr.Map.add
fresh_addr
{ params; body = []; branch = Branch clos_cont }
blocks
in
let outer = { outer with size = outer.size + f_size } in
[], (outer, Branch (fresh_addr, args), { p with blocks; free_pc })
| _ -> i :: rem, state)
| Let (x, Closure (l, (pc, []))) when first_class_primitives -> (
let block = Addr.Map.find pc p.blocks in
match block with
| { body =
( [ Let (y, Prim (Extern prim, args)) ]
| [ Event _; Let (y, Prim (Extern prim, args)) ]
| [ Event _; Let (y, Prim (Extern prim, args)); Event _ ] )
; branch = Return y'
; params = []
} ->
let len = List.length l in
if Code.Var.compare y y' = 0
&& Primitive.has_arity prim len
&& args_equal l args
then Let (x, Special (Alias_prim prim)) :: rem, state
else i :: rem, state
| _ -> i :: rem, state)
| _ -> i :: rem, state)
in
outer, { p with blocks = Addr.Map.add pc { block with body; branch } p.blocks }
(****)
let times = Debug.find "times"
let f p live_vars =
let first_class_primitives =
match Config.target () with
| `JavaScript -> not (Config.Flag.effects ())
| `Wasm -> false
in
Code.invariant p;
let t = Timer.make () in
let closures = get_closures p in
let _closures, p =
Code.fold_closures_innermost_first
p
(fun name cl_params (pc, _) (closures, p) ->
let traverse outer =
Code.traverse
{ fold = Code.fold_children }
(inline ~first_class_primitives live_vars closures name)
pc
p.blocks
(outer, p)
in
match name with
| None ->
let _, p = traverse (optimizable p.blocks pc) in
closures, p
| Some x ->
let info = Var.Map.find x closures in
let outer, p = traverse info.cl_prop in
let cl_simpl = simple_function p.blocks outer.size x cl_params pc in
let closures =
Var.Map.add x { info with cl_prop = outer; cl_simpl } closures
in
closures, p)
(closures, p)
in
if times () then Format.eprintf " inlining: %a@." Timer.print t;
Code.invariant p;
p
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