Source file js_simpl.ml
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open! Stdlib
module J = Javascript
let rec enot_rec e =
let ((_, cost) as res) =
match e with
| J.ESeq (e1, e2) ->
let e2', cost = enot_rec e2 in
J.ESeq (e1, e2'), cost
| J.ECond (e1, e2, e3) ->
let e2', cost2 = enot_rec e2 in
let e3', cost3 = enot_rec e3 in
J.ECond (e1, e2', e3'), cost2 + cost3
| J.EBin (op, e1, e2) -> (
match op with
| J.Or ->
let e1', cost1 = enot_rec e1 in
let e2', cost2 = enot_rec e2 in
J.EBin (J.And, e1', e2'), cost1 + cost2
| J.And ->
let e1', cost1 = enot_rec e1 in
let e2', cost2 = enot_rec e2 in
J.EBin (J.Or, e1', e2'), cost1 + cost2
| J.EqEq -> J.EBin (J.NotEq, e1, e2), 0
| J.NotEq -> J.EBin (J.EqEq, e1, e2), 0
| J.EqEqEq -> J.EBin (J.NotEqEq, e1, e2), 0
| J.NotEqEq -> J.EBin (J.EqEqEq, e1, e2), 0
| _ -> J.EUn (J.Not, e), 1)
| J.EUn (J.Not, e) -> e, 0
| J.EUn ((J.Neg | J.Pl | J.Typeof | J.Void | J.Delete | J.Bnot), _) ->
J.EUn (J.Not, e), 0
| J.EBool b -> J.EBool (not b), 0
| J.ECall _ | J.EAccess _ | J.EDot _ | J.ENew _ | J.EVar _ | J.EFun _ | J.EStr _
| J.EArr _ | J.ENum _ | J.EObj _ | J.EQuote _ | J.ERegexp _
| J.EUn ((J.IncrA | J.IncrB | J.DecrA | J.DecrB), _) ->
J.EUn (J.Not, e), 1
in
if cost <= 1 then res else J.EUn (J.Not, e), 1
let enot e = fst (enot_rec e)
let unblock st =
match st with
| J.Block l, _ -> l
| _ -> [ st ]
let block l =
match l with
| [ x ] -> x
| l -> J.Block l, J.N
exception Not_expression
let rec expression_of_statement_list l =
match l with
| (J.Return_statement (Some e), _) :: _ -> e
| (J.Expression_statement e, _) :: rem -> J.ESeq (e, expression_of_statement_list rem)
| _ -> raise Not_expression
let expression_of_statement st =
match fst st with
| J.Return_statement (Some e) -> e
| J.Block l -> expression_of_statement_list l
| _ -> raise Not_expression
exception Not_assignment
let rec assignment_of_statement_list l =
match l with
| [ (J.Variable_statement [ (x, Some e) ], _) ] -> x, e
| (J.Expression_statement e, _) :: rem ->
let x, (e', nid) = assignment_of_statement_list rem in
x, (J.ESeq (e, e'), nid)
| _ -> raise Not_assignment
let assignment_of_statement st =
match fst st with
| J.Variable_statement [ (x, Some e) ] -> x, e
| J.Block l -> assignment_of_statement_list l
| _ -> raise Not_assignment
let simplify_condition = function
| J.ECond (e, J.ENum one, J.ENum zero) when J.Num.is_one one && J.Num.is_zero zero -> e
| J.ECond (e, J.ENum zero, J.ENum one) when J.Num.is_one one && J.Num.is_zero zero ->
J.EUn (J.Not, e)
| J.ECond (J.EBin ((J.NotEqEq | J.NotEq), J.ENum n, y), e1, e2)
| J.ECond (J.EBin ((J.NotEqEq | J.NotEq), y, J.ENum n), e1, e2) ->
J.ECond (J.EBin (J.Band, y, J.ENum n), e1, e2)
| cond -> cond
let rec if_statement_2 e loc iftrue truestop iffalse falsestop =
let e = simplify_condition e in
match fst iftrue, fst iffalse with
| J.Block [], J.Block [] -> [ J.Expression_statement e, loc ]
| J.Block [], _ -> if_statement_2 (enot e) loc iffalse falsestop iftrue truestop
| _, J.Block [] -> [ J.If_statement (e, iftrue, None), loc ]
| _ -> (
try
let x1, (e1, _) = assignment_of_statement iftrue in
let x2, (e2, _) = assignment_of_statement iffalse in
if Poly.(x1 <> x2) then raise Not_assignment;
let exp = if Poly.(e1 = e) then J.EBin (J.Or, e, e2) else J.ECond (e, e1, e2) in
[ J.Variable_statement [ x1, Some (exp, loc) ], loc ]
with Not_assignment -> (
try
let e1 = expression_of_statement iftrue in
let e2 = expression_of_statement iffalse in
[ J.Return_statement (Some (J.ECond (e, e1, e2))), loc ]
with Not_expression ->
if truestop
then (J.If_statement (e, iftrue, None), loc) :: unblock iffalse
else if falsestop
then (J.If_statement (enot e, iffalse, None), loc) :: unblock iftrue
else [ J.If_statement (e, iftrue, Some iffalse), loc ]))
let unopt b =
match b with
| Some b -> b
| None -> J.Block [], J.N
let if_statement e loc iftrue truestop iffalse falsestop =
let e = simplify_condition e in
match iftrue, iffalse with
| (J.If_statement (e', iftrue', iffalse'), loc), _ when Poly.(iffalse = unopt iffalse')
->
if_statement_2 (J.EBin (J.And, e, e')) loc iftrue' truestop iffalse falsestop
| (J.If_statement (e', iftrue', iffalse'), loc), _ when Poly.(iffalse = iftrue') ->
if_statement_2
(J.EBin (J.And, e, J.EUn (J.Not, e')))
loc
(unopt iffalse')
truestop
iffalse
falsestop
| _, (J.If_statement (e', iftrue', iffalse'), loc) when Poly.(iftrue = iftrue') ->
if_statement_2 (J.EBin (J.Or, e, e')) loc iftrue truestop (unopt iffalse') falsestop
| _, (J.If_statement (e', iftrue', iffalse'), loc) when Poly.(iftrue = unopt iffalse')
->
if_statement_2
(J.EBin (J.Or, e, J.EUn (J.Not, e')))
loc
iftrue
truestop
iftrue'
falsestop
| _ -> if_statement_2 e loc iftrue truestop iffalse falsestop
let rec get_variable acc = function
| J.ESeq (e1, e2) | J.EBin (_, e1, e2) | J.EAccess (e1, e2) ->
get_variable (get_variable acc e1) e2
| J.ECond (e1, e2, e3) -> get_variable (get_variable (get_variable acc e1) e2) e3
| J.EUn (_, e1) | J.EDot (e1, _) | J.ENew (e1, None) -> get_variable acc e1
| J.ECall (e1, el, _) | J.ENew (e1, Some el) ->
List.fold_left ~f:get_variable ~init:acc (e1 :: el)
| J.EVar (J.V v) -> Code.Var.Set.add v acc
| J.EVar (J.S _) -> acc
| J.EFun _ | J.EStr _ | J.EBool _ | J.ENum _ | J.EQuote _ | J.ERegexp _ -> acc
| J.EArr a ->
List.fold_left
~f:(fun acc i ->
match i with
| None -> acc
| Some e1 -> get_variable acc e1)
~init:acc
a
| J.EObj l -> List.fold_left ~f:(fun acc (_, e1) -> get_variable acc e1) ~init:acc l