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Commit 2f6f9ac4 authored by Andrei Paskevich's avatar Andrei Paskevich
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Dexpr: warn if a logical symbol is used outside ghost context 

This may produce false positives in cases like

  let x, ghost y = true, 3 + 42 (* (+) is logical here *)

The use of curly braces will suppress the warning (TODO).
Otherwise, this behaves reasonably well: there were only
two warnings inside examples/, both valid.
parent 9dd49b36
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examples/double_wp/logic.mlw
View file @ 2f6f9ac4
......@@ -156,7 +156,7 @@ module Compiler_logic
(ghost var:post {'a}) : wp 'a
ensures { result.wp --> loop_wp c.wp inv cont var }
ensures { result.wcode.length --> c.wcode.length }
= let wpt = loop_wp c.wp inv cont var in
= let ghost wpt = loop_wp c.wp inv cont var in
assert { forall x p q ms0. wpt x p q ms0 ->
forall ms. inv x p ms -> acc (var x p) ms ->
exists ms'. contextual_irrelevance c.wcode p ms ms' /\ q ms'
......
examples/tests-provers/ieee_float.mlw
View file @ 2f6f9ac4
......@@ -25,7 +25,7 @@ module M603_018
requires { roundToIntegral RTN z = x }
requires { roundToIntegral RTP z = y }
=
let t = (x .+ y) ./ (2.0:t) in
let ghost t = (x .+ y) ./ (2.0:t) in
assert { roundToIntegral RTN x .= x };
assert { roundToIntegral RTN y .= y };
assert { roundToIntegral RTN z .= x };
......
src/mlw/dexpr.ml
View file @ 2f6f9ac4
......@@ -999,6 +999,7 @@ type env = {
lgh : bool; (* we are under let ghost c = <cexp> *)
cgh : bool; (* we are under DEghost in a cexp *)
inr : bool; (* we are inside a recursive function *)
ugh : bool; (* suppress the warning on Cpur *)
}
let env_empty = {
......@@ -1011,6 +1012,7 @@ let env_empty = {
lgh = false;
cgh = false;
inr = false;
ugh = false;
}
exception UnboundLabel of string
......@@ -1146,7 +1148,11 @@ let put_header e = function
type let_prefix =
| LD of header
| EA of expr
| DA of env * dexpr
type let_postfix =
| HD of header
| EA of bool * expr
let vl_of_mask id mask ity =
let mk_res m t = create_pvsymbol id ~ghost:(mask_ghost m) t in
......@@ -1180,40 +1186,42 @@ and cexp uloc env ({de_loc = loc} as de) lpl =
and try_cexp uloc env ({de_dvty = argl,res} as de0) lpl =
let rec drop vl al = match vl, al with
| _::vl, _::al -> drop vl al | _ -> al in
let rec all_ghost al lpl = match al, lpl with
| gh :: al, EA {e_mask = m} :: lpl ->
(not gh && mask_ghost m) || all_ghost al lpl
| _::_, LD _ :: lpl -> all_ghost al lpl
| _, _ -> false in
let rec proxy_args ghost al lpl = match al, lpl with
| _ :: al, EA ({e_node = Evar v} as e) :: lpl
let rec eval_args ghost plp al lpl = match al, lpl with
| gh::al, DA (env, de) :: lpl ->
let env = {env with ugh = env.ugh || ghost || gh} in
let e = e_ghostify env.cgh (expr uloc env de) in
let ghost = ghost || (not gh && mask_ghost e.e_mask) in
eval_args ghost (EA (gh, e) :: plp) al lpl
| al, LD hd :: lpl ->
eval_args ghost (HD hd :: plp) al lpl
| [], _::_ -> assert false (* ill-typed *)
| _, [] -> ghost, plp in
let rec proxy_args ghost ldl vl = function
| EA (_, ({e_node = Evar v} as e)) :: plp
when Slab.is_empty e.e_label ->
let hd, vl = proxy_args ghost al lpl in
hd, v::vl
| gh :: al, EA e :: lpl ->
let hd, vl = proxy_args ghost al lpl in
proxy_args ghost ldl (v::vl) plp
| EA (gh, e) :: plp ->
let id = id_fresh ?loc:e.e_loc ~label:proxy_labels "o" in
let ld, v = let_var ~ghost:(ghost || gh) id e in
LS ld :: hd, v::vl
| al, LD ld :: lpl ->
let hd, vl = proxy_args ghost al lpl in
ld::hd, vl
| [], _::_ ->
assert false (* would be ill-typed *)
| _, [] ->
[], [] in
let apply app ghost s al lpl =
let ldl, vl = proxy_args ghost al lpl in
proxy_args ghost (LS ld :: ldl) (v::vl) plp
| HD hd :: plp ->
proxy_args ghost (hd :: ldl) vl plp
| [] -> ldl, vl in
let apply app gh s al lpl =
let gh, plp = eval_args gh [] al lpl in
let ldl, vl = proxy_args gh [] [] plp in
let argl = List.map ity_of_dity (drop vl argl) in
env.cgh, ldl, app s vl argl (ity_of_dity res) in
let c_app s lpl =
let al = List.map (fun v -> v.pv_ghost) s.rs_cty.cty_args in
let gh = env.ghs || env.lgh || rs_ghost s || all_ghost al lpl in
apply c_app gh s al lpl in
apply c_app (env.ghs || env.lgh || rs_ghost s) s al lpl in
let c_pur s lpl =
let loc = Opt.get_def de0.de_loc uloc in
if not (env.ghs || env.lgh || env.ugh) then Warning.emit ?loc
"Logical symbol %a is used in a non-ghost context" Pretty.print_ls s;
apply c_pur true s (List.map Util.ttrue s.ls_args) lpl in
let c_oop s lpl =
let rs = Srs.choose s in
let al = List.map Util.ffalse rs.rs_cty.cty_args in
let gh = env.ghs || env.lgh || all_ghost al lpl in
let loc = Opt.get_def de0.de_loc uloc in
let app s vl al res =
let nomatch s =
......@@ -1251,12 +1259,11 @@ and try_cexp uloc env ({de_dvty = argl,res} as de0) lpl =
| [] when nomatch s -> Loc.errorm ?loc
"No suitable match found for notation %a" print_rs rs
| _ -> Loc.errorm ?loc "Ambiguous notation: %a" print_rs rs in
apply app gh s al lpl in
let c_pur s lpl =
apply c_pur true s (List.map Util.ttrue s.ls_args) lpl in
let al = List.map Util.ffalse rs.rs_cty.cty_args in
apply app (env.ghs || env.lgh) s al lpl in
let proxy c =
try
let ld_of_lp = function LD ld -> ld | EA _ -> raise Exit in
let ld_of_lp = function LD ld -> ld | DA _ -> raise Exit in
env.cgh, List.map ld_of_lp lpl, c
with Exit ->
let loc = Opt.get_def de0.de_loc uloc in
......@@ -1264,21 +1271,22 @@ and try_cexp uloc env ({de_dvty = argl,res} as de0) lpl =
let ld, s = let_sym id ~ghost:(env.ghs || env.lgh) c in
c_app s (LD (LS ld) :: lpl) in
match de0.de_node with
| DEvar (n,_) -> c_app (get_rs env n) lpl
| DEvar (n,_) -> c_app (get_rs env n) lpl
| DEsym (RS s) -> c_app s lpl
| DEsym (OO s) -> c_oop s lpl
| DEls_pure s -> c_pur s lpl
| DEapp (de1,de2) ->
let e2 = e_ghostify env.cgh (expr uloc env de2) in
cexp uloc env de1 (EA e2 :: lpl)
cexp uloc env de1 (DA (env, de2) :: lpl)
| DEghost de ->
(* if we were not in the ghost context until now, then
we must ghostify the let-definitions down from here *)
cexp uloc {env with ghs = true; cgh = env.cgh || not env.ghs} de lpl
let cgh = env.cgh || not env.ghs in
cexp uloc {env with ghs = true; cgh} de lpl
| DEfun (bl,_,msk,dsp,de) ->
let dvl _ _ _ = [] in
let env = {env with ghs = env.ghs || env.lgh} in
let c, dsp, _ = lambda uloc env (binders env.ghs bl) msk dsp dvl de in
let bl = binders env.ghs bl in
let c, dsp, _ = lambda uloc env bl msk dsp dvl de in
check_fun env.inr None dsp c;
proxy c
| DEany (bl,dity,msk,dsp) ->
......@@ -1320,7 +1328,8 @@ and try_expr uloc env ({de_dvty = argl,res} as de0) =
e_const c (ity_of_dity dity)
| DEapp ({de_dvty = ([],_)} as de1, de2) ->
let e1 = expr uloc env de1 in
let e2 = expr uloc env de2 in
let ugh = env.ugh || e1.e_mask = MaskGhost in
let e2 = expr uloc {env with ugh} de2 in
e_app rs_func_app [e1; e2] [] (ity_of_dity res)
| DEvar _ | DEsym _ | DEls_pure _ | DEapp _ | DEfun _ | DEany _ ->
let cgh,ldl,c = try_cexp uloc env de0 [] in
......@@ -1364,15 +1373,20 @@ and try_expr uloc env ({de_dvty = argl,res} as de0) =
(pp, e_absurd (ity_of_dity res)) :: bl end in
e_case e1 (List.rev bl)
| DEassign al ->
let conv (de1,f,de2) = expr uloc env de1, f, expr uloc env de2 in
let conv (de1,f,de2) =
let e1 = expr uloc {env with ugh = false} de1 in
let ugh = rs_ghost f || e1.e_mask = MaskGhost in
e1, f, expr uloc {env with ugh} de2 in
e_assign (List.map conv al)
| DEwhile (de1,dinv,dvarl,de2) ->
let env = {env with ugh = false} in
let e1 = expr uloc env de1 in
let e2 = expr uloc env de2 in
let inv = get_later env dinv in
let varl = get_later env dvarl in
e_while e1 (create_invariant inv) varl e2
| DEfor (id,de_from,dir,de_to,dinv,de) ->
let env = {env with ugh = false} in
let e_from = expr uloc env de_from in
let e_to = expr uloc env de_to in
let v = create_pvsymbol id e_from.e_ity in
......@@ -1430,7 +1444,9 @@ and try_expr uloc env ({de_dvty = argl,res} as de0) =
vl, e_case e (List.rev bl) in
e_try e1 (Mxs.mapi mk_branch xsm)
| DEraise (xs,de) ->
e_raise (get_xs env xs) (expr uloc env de) (ity_of_dity res)
let {xs_mask = mask} as xs = get_xs env xs in
let env = {env with ugh = mask = MaskGhost} in
e_raise xs (expr uloc env de) (ity_of_dity res)
| DEghost de ->
e_ghostify true (expr uloc {env with ghs = true} de)
| DEassert (ak,f) ->
......@@ -1458,17 +1474,18 @@ and var_defn uloc env (id,gh,kind,de) =
| RKlemma -> Loc.errorm ?loc:id.pre_loc
"Lemma-functions must have parameters"
| RKfunc | RKpred | RKlocal | RKnone ->
e_ghostify env.cgh (expr uloc env de) in
let e = expr uloc {env with ugh = gh} de in
e_ghostify env.cgh e in
let ld, v = let_var id ~ghost:(gh || env.ghs) e in
ld, add_pvsymbol env v
and sym_defn uloc env (id,gh,kind,de) =
let lgh = env.ghs || gh || kind = RKlemma in
let cgh, ldl, c = cexp uloc {env with lgh = lgh} de [] in
let cgh, ldl, c = cexp uloc {env with lgh; ugh = false} de [] in
let ld, s = let_sym id ~ghost:(lgh || cgh) ~kind c in
LS ld :: ldl, add_rsymbol env s
and rec_defn uloc ({inr = inr} as env) {fds = dfdl} =
and rec_defn uloc ({inr = inr} as env0) {fds = dfdl} =
let step1 env (id, gh, kind, bl, res, mask, dsp, dvl, de) =
let ghost = env.ghs || gh || kind = RKlemma in
let pvl = binders ghost bl in
......@@ -1476,7 +1493,8 @@ and rec_defn uloc ({inr = inr} as env) {fds = dfdl} =
let cty = create_cty ~mask pvl [] [] Mxs.empty Mpv.empty eff_empty ity in
let rs = create_rsymbol id ~ghost ~kind:RKnone cty in
add_rsymbol env rs, (rs, kind, mask, dsp, dvl, de) in
let env, fdl = Lists.map_fold_left step1 {env with inr = true} dfdl in
let env = {env0 with inr = true; ugh = false} in
let env, fdl = Lists.map_fold_left step1 env dfdl in
let step2 (rs, kind, mask, dsp, dvl, de) (fdl,dspl) =
let env = {env with ghs = env.ghs || rs_ghost rs} in
let {rs_name = {id_string = nm; id_loc = loc}; rs_cty = c} = rs in
......@@ -1500,10 +1518,11 @@ and rec_defn uloc ({inr = inr} as env) {fds = dfdl} =
let add_fd env {rec_sym = s; rec_rsym = rs; rec_fun = c} dsp =
Loc.try4 ?loc:rs.rs_name.id_loc check_fun inr (Some rs) dsp c;
add_rsymbol env s in
ld, List.fold_left2 add_fd env rdl dspl
ld, List.fold_left2 add_fd env0 rdl dspl
and lambda uloc env pvl mask dsp dvl de =
let env = add_binders env pvl in
let ugh = env.ugh || mask = MaskGhost in
let env = add_binders {env with ugh} pvl in
let preold = Mstr.find_opt old_mark env.old in
let env, old = add_label env old_mark in
let e = if pvl = [] then expr uloc env de else
......@@ -1550,7 +1569,7 @@ let let_defn ?(keep_loc=true) (id, ghost, kind, de) =
fst (let_sym id ~ghost ~kind c)
| (RKfunc | RKpred), ([], _) ->
(* FIXME: let ghost constant c = <effectful> *)
let e = expr uloc env_empty de in
let e = expr uloc {env_empty with ugh = ghost} de in
if mask_ghost e.e_mask && not ghost then Loc.errorm ?loc
"Function %s must be explicitly marked ghost" nm;
let c = c_fun [] [] [] Mxs.empty Mpv.empty e in
......@@ -1565,7 +1584,7 @@ let let_defn ?(keep_loc=true) (id, ghost, kind, de) =
into an axiom. *)
fst (let_sym id ~ghost ~kind c)
| RKnone, ([], _) ->
let e = expr uloc env_empty de in
let e = expr uloc {env_empty with ugh = ghost} de in
if mask_ghost e.e_mask && not ghost then Loc.errorm ?loc
"Variable %s must be explicitly marked ghost" nm;
fst (let_var id ~ghost e)
......
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