75 lines
2.2 KiB
OCaml
75 lines
2.2 KiB
OCaml
(**************************************************************************)
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(* *)
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(* Heptagon *)
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(* *)
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(* Author : Marc Pouzet *)
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(* Organization : Demons, LRI, University of Paris-Sud, Orsay *)
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(* *)
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(**************************************************************************)
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(* control optimisation *)
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(* $Id$ *)
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open Minils
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open Ident
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open Misc
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open Obc
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let var_from_name map x =
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begin try
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Env.find x map
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with
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_ -> assert false
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end
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let fuse_blocks b1 b2 =
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{ b1 with b_locals = b1.b_locals @ b2.b_locals;
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b_body = b1.b_body @ b2.b_body }
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let rec find c = function
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| [] -> raise Not_found
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| (c1, s1) :: h ->
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if c = c1 then s1, h else let s, h = find c h in s, (c1, s1) :: h
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let rec control map ck s =
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match ck with
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| Cbase | Cvar { contents = Cindex _ } -> s
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| Cvar { contents = Clink ck } -> control map ck s
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| Con(ck, c, n) ->
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let x = var_from_name map n in
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control map ck (Acase(mk_exp (Elhs x), [(c, mk_block [s])]))
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let is_deadcode = function
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| Aassgn (lhs, e) ->
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(match e.e_desc with
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| Elhs l -> l = lhs
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| _ -> false
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)
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| Acase (e, []) -> true
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| Afor(_, _, _, { b_body = [] }) -> true
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| _ -> false
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let rec joinlist l =
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let l = List.filter (fun a -> not (is_deadcode a)) l in
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match l with
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| [] -> []
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| [s1] -> [s1]
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| s1::s2::l ->
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match s1, s2 with
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| Acase(e1, h1),
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Acase(e2, h2) when e1.e_desc = e2.e_desc ->
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joinlist ((Acase(e1, joinhandlers h1 h2))::l)
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| s1, s2 -> s1::(joinlist (s2::l))
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and join_block b =
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{ b with b_body = joinlist b.b_body }
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and joinhandlers h1 h2 =
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match h1 with
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| [] -> h2
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| (c1, s1) :: h1' ->
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let s1', h2' =
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try let s2, h2'' = find c1 h2 in fuse_blocks s1 s2, h2''
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with Not_found -> s1, h2 in
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(c1, join_block s1') :: joinhandlers h1' h2'
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