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OCaml

(**************************************************************************)
(* *)
(* Heptagon *)
(* *)
(* Author : Marc Pouzet *)
(* Organization : Demons, LRI, University of Paris-Sud, Orsay *)
(* *)
(**************************************************************************)
(** Remove implicit array's deep copy. If ever some p = e with p of type array still exist,
they are only used as reference to the array, no copy is implied :
array assignation after [scalarize] is pointer wise assignation *)
open Misc
open Obc
open Obc_utils
open Obc_mapfold
(** Scalarize the code : any equation t = e with e_ty an array
is transformed into : t_ref = e; for i do t[i] = t_ref[i].
This pass assumes that the backend when encountering t_ref = (e : int^n) will NOT COPY the array
but set a reference to it. That's why it is declared as an alias.
No t_ref is created if e was an extended value, no calculation is done, so it can be duplicated.
*)
let fresh_for = fresh_for "scalarize"
let act funs () a = match a with
| Aassgn (p, e) ->
(match Modules.unalias_type e.e_ty with
| Types.Tarray (t, size) ->
let new_vd, new_eq, w_from_e = match e.e_desc with
| Eextvalue w -> [], [], w
| _ ->
(* a reference (alias) to the array, since we have a full expression *)
let array_ref = Idents.gen_var "scalarize" "a_ref" in
let vd_array_ref = mk_var_dec ~alias: true array_ref p.pat_ty in
(* reference initialization *)
let pat_array_ref = mk_pattern ~loc: e.e_loc p.pat_ty (Lvar array_ref) in
let init_array_ref = Aassgn (pat_array_ref, e) in
[vd_array_ref], [init_array_ref], ext_value_of_pattern pat_array_ref
in
(* the copy loop with index [i] *)
let array_ref_i i = mk_ext_value_exp t (Warray (w_from_e, i)) in
let p_i i = mk_pattern t (Larray (p, i)) in
let copy_i i =
(* recursive call to deal with multidimensional arrays (go deeper) *)
let a = Aassgn (p_i i, array_ref_i i) in
let a, _ = act_it funs () a in
[a]
in
let copy_array = fresh_for (mk_exp_const_int 0) (mk_exp_static_int size) copy_i in
(* resulting act *)
(match new_vd, new_eq with
| [],[] ->
copy_array, ()
| _ ->
let block = mk_block ~locals: new_vd (new_eq @ [copy_array]) in
Ablock block, ()
)
| _ -> raise Errors.Fallback
)
| _ -> raise Errors.Fallback
let program p =
let p, _ = program_it { defaults with act = act } () p in
p