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