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COMPILER: improve approximation #56

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COMPILER: improve approximation #56

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30 changes: 29 additions & 1 deletion compiler/eval.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,6 @@ let eval_prim x =
| _ -> fun _ -> None in
let float_binop_bool f = float_binop_aux (fun i j -> Int (if f i j then 1 else 0)) in
(match name, l with
| "caml_ml_string_length", [String s] -> Some (Int (String.length s))
(* int *)
| "%int_add", _ -> int_binop (Int.add)
| "%int_sub", _ -> int_binop (Int.sub)
Expand Down Expand Up @@ -108,6 +107,23 @@ let eval_prim x =

exception Not_constant


let the_length_of info x =
get_approx info
(fun x ->
match info.info_defs.(Var.idx x) with
| Expr (Constant (String s))
| Expr (Constant (IString s)) -> Val (String.length s)
| _ -> Top)
Top Bottom
(fun u v -> match u,v with
| Val l,Val l' when l = l' -> Val l
| Bottom,x | x,Bottom -> x
| _ -> Top
)
x


let eval_instr info i =
match i with
| Let (x, Prim (Extern ("caml_js_equals"|"caml_equal"), [y;z])) ->
Expand All @@ -120,6 +136,18 @@ let eval_instr info i =
Let (x , Constant (Int c))
| _ -> i
end
| Let (x,Prim (Extern "caml_ml_string_length", [s])) ->
let c = match s with
| Pc (String s)
| Pc (IString s) -> Some (String.length s)
| Pv v -> begin match the_length_of info v with
| Val i -> Some i
| _ -> None end
| _ -> None
in
(match c with
| None -> i
| Some c -> Let(x,Constant (Int c)))
| Let (x,Prim (prim, prim_args)) ->
begin
let prim_args' = List.map (fun x ->
Expand Down
159 changes: 118 additions & 41 deletions compiler/flow.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -27,10 +27,23 @@ open Code

let add_var = VarISet.add

type def = Phi of VarSet.t | Expr of Code.expr | Param
type def = Phi of VarSet.t | Expr of Code.expr | Param of (Var.t * int) option


type 'a v =
| Bottom
| Val of 'a
| Top

let string_of_approx f = function
| Bottom -> "Bottom"
| Top -> "Top"
| Val i -> Printf.sprintf "Val %s" (f i)


type info = {
info_defs:def array;
info_params: VarSet.t array array;
info_known_origins : Code.VarSet.t Code.VarTbl.t;
info_maybe_unknown : bool Code.VarTbl.t;
info_possibly_mutable : bool array
Expand All @@ -50,16 +63,32 @@ let add_assign_def vars defs x y =
add_var vars x;
let idx = Var.idx x in
match defs.(idx) with
Expr _ | Param ->
Expr _ | Param _ ->
assert false
| Phi s ->
defs.(idx) <- Phi (VarSet.add y s)

let add_param_def vars defs x =

let add_params_origin state f args =
let fx = Var.idx f in
let argsl = List.length args in
let a =
if Array.length state.(fx) < argsl
then
let a = Array.make argsl VarSet.empty in
Array.blit state.(fx) 0 a 0 (Array.length state.(fx));
state.(fx) <- a;
a
else state.(fx) in
List.iteri (fun i ar -> a.(i) <- VarSet.add ar a.(i) ) args

let add_param_def vars defs x extra =
add_var vars x;
let idx = Var.idx x in
assert (is_undefined defs.(idx) || defs.(idx) = Param);
defs.(idx) <- Param
match defs.(idx) with
| x when is_undefined x -> defs.(idx) <- Param extra
| Param x' when x' = extra -> ()
| _ -> assert false

(* x depends on y *)
let add_dep deps x y =
Expand All @@ -79,38 +108,41 @@ let cont_deps blocks vars deps defs (pc, args) =
let block = AddrMap.find pc blocks in
arg_deps vars deps defs block.params args

let expr_deps blocks vars deps defs x e =
let expr_deps blocks vars deps defs params x e =
match e with
Const _ | Constant _ | Apply _ | Prim _ ->
| Const _ | Constant _ | Prim _ ->
()
| Closure (l, cont) ->
List.iter (fun x -> add_param_def vars defs x) l;
| Apply (f,args,_) ->
add_params_origin params f args
| Closure (l, cont) ->
List.iteri (fun i v -> add_param_def vars defs v (Some (x,i))) l;
cont_deps blocks vars deps defs cont
| Block (_, a) ->
| Block (_, a) ->
Array.iter (fun y -> add_dep deps x y) a
| Field (y, _) ->
| Field (y, _) ->
add_dep deps x y

let program_deps (_, blocks, _) =
let nv = Var.count () in
let vars = VarISet.empty () in
let deps = Array.make nv VarSet.empty in
let defs = Array.make nv undefined in
let params = Array.make nv [||] in
AddrMap.iter
(fun pc block ->
List.iter
(fun i ->
match i with
Let (x, e) ->
| Let (x, e) ->
add_var vars x;
add_expr_def defs x e;
expr_deps blocks vars deps defs x e
| Set_field _ | Array_set _ | Offset_ref _ ->
expr_deps blocks vars deps defs params x e
| Set_field _ | Array_set _ | Offset_ref _ ->
())
block.body;
Util.opt_iter
(fun (x, cont) ->
add_param_def vars defs x;
add_param_def vars defs x None;
cont_deps blocks vars deps defs cont)
block.handler;
match block.branch with
Expand All @@ -127,14 +159,14 @@ let program_deps (_, blocks, _) =
| Pushtrap (cont, _, _, _) ->
cont_deps blocks vars deps defs cont)
blocks;
(vars, deps, defs)
(vars, deps, defs,params)

let var_set_lift f s =
VarSet.fold (fun y s -> VarSet.union (f y) s) s VarSet.empty

let propagate1 deps defs st x =
match defs.(Var.idx x) with
Param ->
Param _ ->
VarSet.singleton x
| Phi s ->
var_set_lift (fun y -> VarTbl.get st y) s
Expand All @@ -151,7 +183,7 @@ let propagate1 deps defs st x =
let t = a.(n) in
add_dep deps x t;
VarTbl.get st t
| Phi _ | Param | Expr _ ->
| Phi _ | Param _ | Expr _ ->
VarSet.empty)
(VarTbl.get st y)

Expand Down Expand Up @@ -253,7 +285,7 @@ let approx_lift f s = VarSet.fold (fun y u -> a_max (f y) u) s Known

let propagate2 ?(skip_param=false) defs known_origins possibly_mutable st x =
match defs.(Var.idx x) with
Param -> skip_param
Param _ -> skip_param
| Phi s ->
VarSet.exists (fun y -> VarTbl.get st y) s
| Expr e ->
Expand All @@ -272,7 +304,7 @@ let propagate2 ?(skip_param=false) defs known_origins possibly_mutable st x =
possibly_mutable.(Var.idx z)
||
VarTbl.get st a.(n)
| Phi _ | Param | Expr _ ->
| Phi _ | Param _| Expr _ ->
true)
(VarTbl.get known_origins y)

Expand All @@ -291,33 +323,77 @@ let solver2 ?skip_param vars deps defs known_origins possibly_mutable =
in
Solver2.f () g (propagate2 ?skip_param defs known_origins possibly_mutable)

let get_approx {info_defs; info_known_origins;info_maybe_unknown} f top join x =
let s = VarTbl.get info_known_origins x in
if VarTbl.get info_maybe_unknown x then top else
match VarSet.cardinal s with
0 -> top
| 1 -> f (VarSet.choose s)
| _ -> VarSet.fold (fun x u -> join (f x) u) s (f (VarSet.choose s))
let get_approx {info_defs; info_known_origins;info_maybe_unknown;info_possibly_mutable;info_params} f top bottom join x =
let rec aux visited x =
let visited = VarSet.add x visited in
let s = VarTbl.get info_known_origins x in
if VarTbl.get info_maybe_unknown x then top,visited else
match VarSet.cardinal s with
| 0 -> bottom,visited
| 1 ->
begin
let x = VarSet.choose s in
match info_defs.(Var.idx x) with
| Param (Some (fct,i)) ->
let idx_f = Var.idx fct in
(* check if fct can escape *)
if info_possibly_mutable.(idx_f)
then top,visited
else
let a = info_params.(idx_f) in
if Array.length a > i
then
let s = a.(i) in
let s = VarSet.elements s in
let rec loop visited res = function
| [] -> res,visited
| x::xs ->
if VarSet.mem x visited
then loop visited res xs
else
let visited = VarSet.add x visited in
let r,visited = aux visited x in
let res = join r res in
loop visited res xs
in loop visited bottom s
else top,visited
| _ -> f x,visited
end
| _ -> VarSet.fold (fun x (u,visited) -> join (f x) u, visited) s (f (VarSet.choose s), visited)
in
fst(aux VarSet.empty x)


let the_def_of info x =
match x with
| Pv x ->
get_approx info
(fun x -> match info.info_defs.(Var.idx x) with Expr e -> Some e | _ -> None)
None (fun u v -> None) x
| Pc c -> Some (Constant c)
| Pv x ->
let v = get_approx info
(fun x -> match info.info_defs.(Var.idx x) with
| Expr e -> Val e
| _ -> Top)
Top Bottom (fun u v -> Top) x in
match v with
| Val v -> Some v
| _ -> None

let the_int info x =
match x with
| Pv x ->
get_approx info
| Pv x -> begin
let v = get_approx info
(fun x -> match info.info_defs.(Var.idx x) with
| Expr (Const i) -> Some i
| Expr (Constant (Int i)) -> Some i
| _ -> None)
None
(fun u v -> match u, v with Some i, Some j when i = j -> u | _ -> None)
x
| Expr (Const i) -> Val i
| Expr (Constant (Int i)) -> Val i
| _ -> Top)
Top Bottom
(fun u v -> match u, v with
| Val i, Val j when i = j -> u
| Bottom, x | x, Bottom -> x
| _ -> Top) x in
match v with
| Val v -> Some v
| _ -> None
end
| Pc (Int i) -> Some i
| _ -> None

Expand All @@ -333,7 +409,7 @@ let direct_approx info x =
Some a.(n)
| _ ->
None)
None
None None
(fun u v ->
match u, v with
Some n, Some m when Var.compare n m = 0 -> u
Expand Down Expand Up @@ -364,7 +440,7 @@ let build_subst info vars =
let f ?skip_param ((pc, blocks, free_pc) as p) =
let t = Util.Timer.make () in
let t1 = Util.Timer.make () in
let (vars, deps, defs) = program_deps p in
let (vars, deps, defs,params) = program_deps p in
if times () then Format.eprintf " flow analysis 1: %a@." Util.Timer.print t1;
let t2 = Util.Timer.make () in
let known_origins = solver1 vars deps defs in
Expand All @@ -391,6 +467,7 @@ let f ?skip_param ((pc, blocks, free_pc) as p) =
let t5 = Util.Timer.make () in
let info = {
info_defs = defs;
info_params = params;
info_known_origins = known_origins;
info_maybe_unknown = maybe_unknown;
info_possibly_mutable = possibly_mutable;
Expand Down
12 changes: 10 additions & 2 deletions compiler/flow.mli
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Expand Up @@ -37,17 +37,25 @@ val get_label : t -> Code.Var.t option

*)

type def = Phi of Code.VarSet.t | Expr of Code.expr | Param
type def = Phi of Code.VarSet.t | Expr of Code.expr | Param of (Code.Var.t * int) option

type 'a v =
| Bottom
| Val of 'a
| Top

val string_of_approx : ('a -> string ) -> 'a v -> string

type info = {
info_defs:def array;
info_params: Code.VarSet.t array array;
info_known_origins : Code.VarSet.t Code.VarTbl.t;
info_maybe_unknown : bool Code.VarTbl.t;
info_possibly_mutable : bool array;
}

val get_approx : info -> (Code.VarSet.elt -> 'b) ->
'b -> ('b -> 'b -> 'b) -> Code.VarTbl.key -> 'b
'b -> 'b -> ('b -> 'b -> 'b) -> Code.VarTbl.key -> 'b

val the_def_of : info -> Code.prim_arg -> Code.expr option

Expand Down
21 changes: 14 additions & 7 deletions compiler/specialize.ml
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Expand Up @@ -24,17 +24,24 @@ open Flow
let function_cardinality info x =
get_approx info
(fun x ->
match info.info_defs.(Var.idx x) with
Expr (Closure (l, _)) -> Some (List.length l)
| _ -> None)
None
(fun u v -> match u, v with Some n, Some m when n = m -> u | _ -> None)
match info.info_defs.(Var.idx x) with
| Expr (Closure (l, _)) ->
Val (List.length l)
| _ -> Top)
Top Bottom
(fun u v -> match u, v with
| Val n, Val m when n = m -> u
| Bottom, x | x, Bottom -> x
| x -> Top)
x

let specialize_instr info i =
match i with
| Let (x, Apply (f, l, _)) when Option.Optim.optcall () ->
Let (x, Apply (f, l, function_cardinality info f))
| Let (x, Apply (f, l, None)) when Option.Optim.optcall () ->
let nopt = match function_cardinality info f with
| Val n -> Some n
| _ -> None in
Let (x, Apply (f, l, nopt))
| _ ->
i

Expand Down