Do not loop forever during code generation

- Detect when the computation of the static exp
using simplif failed and abort.
- Added a better way to compute operators in
Static
This commit is contained in:
Cédric Pasteur 2010-07-16 12:04:51 +02:00
parent 3f7564aaa6
commit 778dfdb3f9
2 changed files with 36 additions and 23 deletions

View file

@ -31,19 +31,6 @@ let op_from_app_name ln =
| Modname { qual = "Pervasives" } -> ln
| _ -> raise Not_static
(** Applies the operator [op] to the two integers [n1] and [n2]
and returns the reslt as a static exp. *)
let apply_int_op op n1 n2 =
match op with
| Modname { qual = "Pervasives"; id = "+" } -> Sint (n1 + n2)
| Modname { qual = "Pervasives"; id = "-" } -> Sint (n1 - n2)
| Modname { qual = "Pervasives"; id = "*" } -> Sint (n1 * n2)
| Modname { qual = "Pervasives"; id = "/" } ->
let n = if n2 = 0 then raise Instanciation_failed else n1 / n2 in
Sint n
| _ -> (* unknown operator, reconstrcut the op *)
Sop (op, [mk_static_exp (Sint n1); mk_static_exp (Sint n2)]) (*TODO CP*)
(** [simplify env e] returns e simplified with the
variables values taken from env (mapping vars to integers).
Variables are replaced with their values and every operator
@ -61,15 +48,9 @@ let rec simplify env se =
| Name n -> (try simplify env (NamesEnv.find n env) with | _ -> se)
| Modname _ -> se)
)
| Sop (op, [e1; e2]) ->
let e1 = simplify env e1 in
let e2 = simplify env e2 in
(match e1.se_desc, e2.se_desc with
| Sint n1, Sint n2 -> { se with se_desc = apply_int_op op n1 n2 }
| _, _ -> { se with se_desc = Sop (op, [e1; e2]) }
)
| Sop (op, se_list) ->
{ se with se_desc = Sop (op, List.map (simplify env) se_list) }
let se_list = List.map (simplify env) se_list in
{ se with se_desc = apply_op op se_list }
| Sarray se_list ->
{ se with se_desc = Sarray (List.map (simplify env) se_list) }
| Sarray_power (se, n) ->
@ -80,6 +61,28 @@ let rec simplify env se =
{ se with se_desc = Srecord
(List.map (fun (f,se) -> f, simplify env se) f_se_list) }
and apply_op op se_list =
match se_list with
| [{ se_desc = Sint n1 }; { se_desc = Sint n2 }] ->
(match op with
| Modname { qual = "Pervasives"; id = "+" } ->
Sint (n1 + n2)
| Modname { qual = "Pervasives"; id = "-" } ->
Sint (n1 - n2)
| Modname { qual = "Pervasives"; id = "*" } ->
Sint (n1 * n2)
| Modname { qual = "Pervasives"; id = "/" } ->
let n = if n2 = 0 then raise Instanciation_failed else n1 / n2 in
Sint n
| _ -> assert false (*TODO: add missing operators*)
)
| [{ se_desc = Sint n }] ->
(match op with
| Modname { qual = "Pervasives"; id = "~-" } -> Sint (-n)
| _ -> assert false (*TODO: add missing operators*)
)
| _ -> Sop(op, se_list)
(** [int_of_static_exp env e] returns the value of the expression
[e] in the environment [env], mapping vars to integers. Raises
Instanciation_failed if it cannot be computed (if a var has no value).*)

View file

@ -27,6 +27,7 @@ struct
| Enode of string
| Eno_unnamed_output
| Ederef_not_pointer
| Estatic_exp_compute_failed
let message loc kind = (match kind with
| Evar name ->
@ -40,7 +41,11 @@ struct
output_location loc
| Ederef_not_pointer ->
eprintf "%aCode generation : Trying to deference a non pointer type.\n"
output_location loc );
output_location loc
| Estatic_exp_compute_failed ->
eprintf "%aCode generation : Computation of the value of the static \
expression failed.\n"
output_location loc);
raise Misc.Error
end
@ -261,7 +266,12 @@ let rec cexpr_of_static_exp se =
let { info = cd } = find_const ln in
cexpr_of_static_exp (Static.simplify NamesEnv.empty cd.c_value)
with Not_found -> assert false)
| Sop _ -> cexpr_of_static_exp (Static.simplify NamesEnv.empty se)
| Sop _ ->
let se' = Static.simplify NamesEnv.empty se in
if se = se' then
Error.message se.se_loc Error.Estatic_exp_compute_failed
else
cexpr_of_static_exp se'
(** [cexpr_of_exp exp] translates the Obj action [exp] to a C expression. *)
let rec cexpr_of_exp var_env exp =