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+(************************************************************************)
+(* v * The Coq Proof Assistant / The Coq Development Team *)
+(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
+(* \VV/ **************************************************************)
+(* // * This file is distributed under the terms of the *)
+(* * GNU Lesser General Public License Version 2.1 *)
+(************************************************************************)
+
+(*i $Id$ i*)
+
+(*i*)
+open Pp
+open Util
+open Names
+open Libnames
+open Nametab
+open Table
+open Miniml
+(*i*)
+
+(*s Exceptions. *)
+
+exception Found
+exception Impossible
+
+(*S Names operations. *)
+
+let anonymous_name = id_of_string "x"
+let dummy_name = id_of_string "_"
+
+let anonymous = Id anonymous_name
+
+let id_of_name = function
+ | Anonymous -> anonymous_name
+ | Name id when id = dummy_name -> anonymous_name
+ | Name id -> id
+
+let id_of_mlid = function
+ | Dummy -> dummy_name
+ | Id id -> id
+ | Tmp id -> id
+
+let tmp_id = function
+ | Id id -> Tmp id
+ | a -> a
+
+let is_tmp = function Tmp _ -> true | _ -> false
+
+(*S Operations upon ML types (with meta). *)
+
+let meta_count = ref 0
+
+let reset_meta_count () = meta_count := 0
+
+let new_meta _ =
+ incr meta_count;
+ Tmeta {id = !meta_count; contents = None}
+
+(*s Sustitution of [Tvar i] by [t] in a ML type. *)
+
+let type_subst i t0 t =
+ let rec subst t = match t with
+ | Tvar j when i = j -> t0
+ | Tmeta {contents=None} -> t
+ | Tmeta {contents=Some u} -> subst u
+ | Tarr (a,b) -> Tarr (subst a, subst b)
+ | Tglob (r, l) -> Tglob (r, List.map subst l)
+ | a -> a
+ in subst t
+
+(* Simultaneous substitution of [[Tvar 1; ... ; Tvar n]] by [l] in a ML type. *)
+
+let type_subst_list l t =
+ let rec subst t = match t with
+ | Tvar j -> List.nth l (j-1)
+ | Tmeta {contents=None} -> t
+ | Tmeta {contents=Some u} -> subst u
+ | Tarr (a,b) -> Tarr (subst a, subst b)
+ | Tglob (r, l) -> Tglob (r, List.map subst l)
+ | a -> a
+ in subst t
+
+(* Simultaneous substitution of [[|Tvar 1; ... ; Tvar n|]] by [v] in a ML type. *)
+
+let type_subst_vect v t =
+ let rec subst t = match t with
+ | Tvar j -> v.(j-1)
+ | Tmeta {contents=None} -> t
+ | Tmeta {contents=Some u} -> subst u
+ | Tarr (a,b) -> Tarr (subst a, subst b)
+ | Tglob (r, l) -> Tglob (r, List.map subst l)
+ | a -> a
+ in subst t
+
+(*s From a type schema to a type. All [Tvar] become fresh [Tmeta]. *)
+
+let instantiation (nb,t) = type_subst_vect (Array.init nb new_meta) t
+
+(*s Occur-check of a free meta in a type *)
+
+let rec type_occurs alpha t =
+ match t with
+ | Tmeta {id=beta; contents=None} -> alpha = beta
+ | Tmeta {contents=Some u} -> type_occurs alpha u
+ | Tarr (t1, t2) -> type_occurs alpha t1 || type_occurs alpha t2
+ | Tglob (r,l) -> List.exists (type_occurs alpha) l
+ | _ -> false
+
+(*s Most General Unificator *)
+
+let rec mgu = function
+ | Tmeta m, Tmeta m' when m.id = m'.id -> ()
+ | Tmeta m, t when m.contents=None ->
+ if type_occurs m.id t then raise Impossible
+ else m.contents <- Some t
+ | t, Tmeta m when m.contents=None ->
+ if type_occurs m.id t then raise Impossible
+ else m.contents <- Some t
+ | Tmeta {contents=Some u}, t -> mgu (u, t)
+ | t, Tmeta {contents=Some u} -> mgu (t, u)
+ | Tarr(a, b), Tarr(a', b') ->
+ mgu (a, a'); mgu (b, b')
+ | Tglob (r,l), Tglob (r',l') when r = r' ->
+ List.iter mgu (List.combine l l')
+ | Tvar i, Tvar j when i = j -> ()
+ | Tvar' i, Tvar' j when i = j -> ()
+ | Tdummy _, Tdummy _ -> ()
+ | Tunknown, Tunknown -> ()
+ | _ -> raise Impossible
+
+let needs_magic p = try mgu p; false with Impossible -> true
+
+let put_magic_if b a = if b && lang () <> Scheme then MLmagic a else a
+
+let put_magic p a = if needs_magic p && lang () <> Scheme then MLmagic a else a
+
+
+(*S ML type env. *)
+
+module Mlenv = struct
+
+ let meta_cmp m m' = compare m.id m'.id
+ module Metaset = Set.Make(struct type t = ml_meta let compare = meta_cmp end)
+
+ (* Main MLenv type. [env] is the real environment, whereas [free]
+ (tries to) record the free meta variables occurring in [env]. *)
+
+ type t = { env : ml_schema list; mutable free : Metaset.t}
+
+ (* Empty environment. *)
+
+ let empty = { env = []; free = Metaset.empty }
+
+ (* [get] returns a instantiated copy of the n-th most recently added
+ type in the environment. *)
+
+ let get mle n =
+ assert (List.length mle.env >= n);
+ instantiation (List.nth mle.env (n-1))
+
+ (* [find_free] finds the free meta in a type. *)
+
+ let rec find_free set = function
+ | Tmeta m when m.contents = None -> Metaset.add m set
+ | Tmeta {contents = Some t} -> find_free set t
+ | Tarr (a,b) -> find_free (find_free set a) b
+ | Tglob (_,l) -> List.fold_left find_free set l
+ | _ -> set
+
+ (* The [free] set of an environment can be outdate after
+ some unifications. [clean_free] takes care of that. *)
+
+ let clean_free mle =
+ let rem = ref Metaset.empty
+ and add = ref Metaset.empty in
+ let clean m = match m.contents with
+ | None -> ()
+ | Some u -> rem := Metaset.add m !rem; add := find_free !add u
+ in
+ Metaset.iter clean mle.free;
+ mle.free <- Metaset.union (Metaset.diff mle.free !rem) !add
+
+ (* From a type to a type schema. If a [Tmeta] is still uninstantiated
+ and does appears in the [mle], then it becomes a [Tvar]. *)
+
+ let generalization mle t =
+ let c = ref 0 in
+ let map = ref (Intmap.empty : int Intmap.t) in
+ let add_new i = incr c; map := Intmap.add i !c !map; !c in
+ let rec meta2var t = match t with
+ | Tmeta {contents=Some u} -> meta2var u
+ | Tmeta ({id=i} as m) ->
+ (try Tvar (Intmap.find i !map)
+ with Not_found ->
+ if Metaset.mem m mle.free then t
+ else Tvar (add_new i))
+ | Tarr (t1,t2) -> Tarr (meta2var t1, meta2var t2)
+ | Tglob (r,l) -> Tglob (r, List.map meta2var l)
+ | t -> t
+ in !c, meta2var t
+
+ (* Adding a type in an environment, after generalizing. *)
+
+ let push_gen mle t =
+ clean_free mle;
+ { env = generalization mle t :: mle.env; free = mle.free }
+
+ (* Adding a type with no [Tvar], hence no generalization needed. *)
+
+ let push_type {env=e;free=f} t =
+ { env = (0,t) :: e; free = find_free f t}
+
+ (* Adding a type with no [Tvar] nor [Tmeta]. *)
+
+ let push_std_type {env=e;free=f} t =
+ { env = (0,t) :: e; free = f}
+
+end
+
+(*S Operations upon ML types (without meta). *)
+
+(*s Does a section path occur in a ML type ? *)
+
+let rec type_mem_kn kn = function
+ | Tmeta {contents = Some t} -> type_mem_kn kn t
+ | Tglob (r,l) -> occur_kn_in_ref kn r || List.exists (type_mem_kn kn) l
+ | Tarr (a,b) -> (type_mem_kn kn a) || (type_mem_kn kn b)
+ | _ -> false
+
+(*s Greatest variable occurring in [t]. *)
+
+let type_maxvar t =
+ let rec parse n = function
+ | Tmeta {contents = Some t} -> parse n t
+ | Tvar i -> max i n
+ | Tarr (a,b) -> parse (parse n a) b
+ | Tglob (_,l) -> List.fold_left parse n l
+ | _ -> n
+ in parse 0 t
+
+(*s What are the type variables occurring in [t]. *)
+
+let intset_union_map_list f l =
+ List.fold_left (fun s t -> Intset.union s (f t)) Intset.empty l
+
+let intset_union_map_array f a =
+ Array.fold_left (fun s t -> Intset.union s (f t)) Intset.empty a
+
+let rec type_listvar = function
+ | Tmeta {contents = Some t} -> type_listvar t
+ | Tvar i | Tvar' i -> Intset.singleton i
+ | Tarr (a,b) -> Intset.union (type_listvar a) (type_listvar b)
+ | Tglob (_,l) -> intset_union_map_list type_listvar l
+ | _ -> Intset.empty
+
+(*s From [a -> b -> c] to [[a;b],c]. *)
+
+let rec type_decomp = function
+ | Tmeta {contents = Some t} -> type_decomp t
+ | Tarr (a,b) -> let l,h = type_decomp b in a::l, h
+ | a -> [],a
+
+(*s The converse: From [[a;b],c] to [a -> b -> c]. *)
+
+let rec type_recomp (l,t) = match l with
+ | [] -> t
+ | a::l -> Tarr (a, type_recomp (l,t))
+
+(*s Translating [Tvar] to [Tvar'] to avoid clash. *)
+
+let rec var2var' = function
+ | Tmeta {contents = Some t} -> var2var' t
+ | Tvar i -> Tvar' i
+ | Tarr (a,b) -> Tarr (var2var' a, var2var' b)
+ | Tglob (r,l) -> Tglob (r, List.map var2var' l)
+ | a -> a
+
+type abbrev_map = global_reference -> ml_type option
+
+(*s Delta-reduction of type constants everywhere in a ML type [t].
+ [env] is a function of type [ml_type_env]. *)
+
+let type_expand env t =
+ let rec expand = function
+ | Tmeta {contents = Some t} -> expand t
+ | Tglob (r,l) ->
+ (match env r with
+ | Some mlt -> expand (type_subst_list l mlt)
+ | None -> Tglob (r, List.map expand l))
+ | Tarr (a,b) -> Tarr (expand a, expand b)
+ | a -> a
+ in if Table.type_expand () then expand t else t
+
+(*s Generating a signature from a ML type. *)
+
+let type_to_sign env t = match type_expand env t with
+ | Tdummy d -> Kill d
+ | _ -> Keep
+
+let type_to_signature env t =
+ let rec f = function
+ | Tmeta {contents = Some t} -> f t
+ | Tarr (Tdummy d, b) -> Kill d :: f b
+ | Tarr (_, b) -> Keep :: f b
+ | _ -> []
+ in f (type_expand env t)
+
+let isKill = function Kill _ -> true | _ -> false
+
+let isDummy = function Tdummy _ -> true | _ -> false
+
+let sign_of_id = function
+ | Dummy -> Kill Kother
+ | _ -> Keep
+
+(* Classification of signatures *)
+
+type sign_kind =
+ | EmptySig
+ | NonLogicalSig (* at least a [Keep] *)
+ | UnsafeLogicalSig (* No [Keep], at least a [Kill Kother] *)
+ | SafeLogicalSig (* only [Kill Ktype] *)
+
+let rec sign_kind = function
+ | [] -> EmptySig
+ | Keep :: _ -> NonLogicalSig
+ | Kill k :: s ->
+ match sign_kind s with
+ | NonLogicalSig -> NonLogicalSig
+ | UnsafeLogicalSig -> UnsafeLogicalSig
+ | SafeLogicalSig | EmptySig ->
+ if k = Kother then UnsafeLogicalSig else SafeLogicalSig
+
+(* Removing the final [Keep] in a signature *)
+
+let rec sign_no_final_keeps = function
+ | [] -> []
+ | k :: s ->
+ let s' = k :: sign_no_final_keeps s in
+ if s' = [Keep] then [] else s'
+
+(*s Removing [Tdummy] from the top level of a ML type. *)
+
+let type_expunge_from_sign env s t =
+ let rec expunge s t =
+ if s = [] then t else match t with
+ | Tmeta {contents = Some t} -> expunge s t
+ | Tarr (a,b) ->
+ let t = expunge (List.tl s) b in
+ if List.hd s = Keep then Tarr (a, t) else t
+ | Tglob (r,l) ->
+ (match env r with
+ | Some mlt -> expunge s (type_subst_list l mlt)
+ | None -> assert false)
+ | _ -> assert false
+ in
+ let t = expunge (sign_no_final_keeps s) t in
+ if lang () <> Haskell && sign_kind s = UnsafeLogicalSig then
+ Tarr (Tdummy Kother, t)
+ else t
+
+let type_expunge env t =
+ type_expunge_from_sign env (type_to_signature env t) t
+
+(*S Generic functions over ML ast terms. *)
+
+let mlapp f a = if a = [] then f else MLapp (f,a)
+
+(*s [ast_iter_rel f t] applies [f] on every [MLrel] in t. It takes care
+ of the number of bingings crossed before reaching the [MLrel]. *)
+
+let ast_iter_rel f =
+ let rec iter n = function
+ | MLrel i -> f (i-n)
+ | MLlam (_,a) -> iter (n+1) a
+ | MLletin (_,a,b) -> iter n a; iter (n+1) b
+ | MLcase (_,a,v) ->
+ iter n a; Array.iter (fun (_,l,t) -> iter (n + (List.length l)) t) v
+ | MLfix (_,ids,v) -> let k = Array.length ids in Array.iter (iter (n+k)) v
+ | MLapp (a,l) -> iter n a; List.iter (iter n) l
+ | MLcons (_,_,l) -> List.iter (iter n) l
+ | MLmagic a -> iter n a
+ | MLglob _ | MLexn _ | MLdummy | MLaxiom -> ()
+ in iter 0
+
+(*s Map over asts. *)
+
+let ast_map_case f (c,ids,a) = (c,ids,f a)
+
+let ast_map f = function
+ | MLlam (i,a) -> MLlam (i, f a)
+ | MLletin (i,a,b) -> MLletin (i, f a, f b)
+ | MLcase (i,a,v) -> MLcase (i,f a, Array.map (ast_map_case f) v)
+ | MLfix (i,ids,v) -> MLfix (i, ids, Array.map f v)
+ | MLapp (a,l) -> MLapp (f a, List.map f l)
+ | MLcons (i,c,l) -> MLcons (i,c, List.map f l)
+ | MLmagic a -> MLmagic (f a)
+ | MLrel _ | MLglob _ | MLexn _ | MLdummy | MLaxiom as a -> a
+
+(*s Map over asts, with binding depth as parameter. *)
+
+let ast_map_lift_case f n (c,ids,a) = (c,ids, f (n+(List.length ids)) a)
+
+let ast_map_lift f n = function
+ | MLlam (i,a) -> MLlam (i, f (n+1) a)
+ | MLletin (i,a,b) -> MLletin (i, f n a, f (n+1) b)
+ | MLcase (i,a,v) -> MLcase (i,f n a,Array.map (ast_map_lift_case f n) v)
+ | MLfix (i,ids,v) ->
+ let k = Array.length ids in MLfix (i,ids,Array.map (f (k+n)) v)
+ | MLapp (a,l) -> MLapp (f n a, List.map (f n) l)
+ | MLcons (i,c,l) -> MLcons (i,c, List.map (f n) l)
+ | MLmagic a -> MLmagic (f n a)
+ | MLrel _ | MLglob _ | MLexn _ | MLdummy | MLaxiom as a -> a
+
+(*s Iter over asts. *)
+
+let ast_iter_case f (c,ids,a) = f a
+
+let ast_iter f = function
+ | MLlam (i,a) -> f a
+ | MLletin (i,a,b) -> f a; f b
+ | MLcase (_,a,v) -> f a; Array.iter (ast_iter_case f) v
+ | MLfix (i,ids,v) -> Array.iter f v
+ | MLapp (a,l) -> f a; List.iter f l
+ | MLcons (_,c,l) -> List.iter f l
+ | MLmagic a -> f a
+ | MLrel _ | MLglob _ | MLexn _ | MLdummy | MLaxiom -> ()
+
+(*S Operations concerning De Bruijn indices. *)
+
+(*s [ast_occurs k t] returns [true] if [(Rel k)] occurs in [t]. *)
+
+let ast_occurs k t =
+ try
+ ast_iter_rel (fun i -> if i = k then raise Found) t; false
+ with Found -> true
+
+(*s [occurs_itvl k k' t] returns [true] if there is a [(Rel i)]
+ in [t] with [k<=i<=k'] *)
+
+let ast_occurs_itvl k k' t =
+ try
+ ast_iter_rel (fun i -> if (k <= i) && (i <= k') then raise Found) t; false
+ with Found -> true
+
+(*s Number of occurences of [Rel k] (resp. [Rel 1]) in [t]. *)
+
+let nb_occur_k k t =
+ let cpt = ref 0 in
+ ast_iter_rel (fun i -> if i = k then incr cpt) t;
+ !cpt
+
+let nb_occur t = nb_occur_k 1 t
+
+(* Number of occurences of [Rel 1] in [t], with special treatment of match:
+ occurences in different branches aren't added, but we rather use max. *)
+
+let nb_occur_match =
+ let rec nb k = function
+ | MLrel i -> if i = k then 1 else 0
+ | MLcase(_,a,v) ->
+ (nb k a) +
+ Array.fold_left
+ (fun r (_,ids,a) -> max r (nb (k+(List.length ids)) a)) 0 v
+ | MLletin (_,a,b) -> (nb k a) + (nb (k+1) b)
+ | MLfix (_,ids,v) -> let k = k+(Array.length ids) in
+ Array.fold_left (fun r a -> r+(nb k a)) 0 v
+ | MLlam (_,a) -> nb (k+1) a
+ | MLapp (a,l) -> List.fold_left (fun r a -> r+(nb k a)) (nb k a) l
+ | MLcons (_,_,l) -> List.fold_left (fun r a -> r+(nb k a)) 0 l
+ | MLmagic a -> nb k a
+ | MLglob _ | MLexn _ | MLdummy | MLaxiom -> 0
+ in nb 1
+
+(*s Lifting on terms.
+ [ast_lift k t] lifts the binding depth of [t] across [k] bindings. *)
+
+let ast_lift k t =
+ let rec liftrec n = function
+ | MLrel i as a -> if i-n < 1 then a else MLrel (i+k)
+ | a -> ast_map_lift liftrec n a
+ in if k = 0 then t else liftrec 0 t
+
+let ast_pop t = ast_lift (-1) t
+
+(*s [permut_rels k k' c] translates [Rel 1 ... Rel k] to [Rel (k'+1) ...
+ Rel (k'+k)] and [Rel (k+1) ... Rel (k+k')] to [Rel 1 ... Rel k'] *)
+
+let permut_rels k k' =
+ let rec permut n = function
+ | MLrel i as a ->
+ let i' = i-n in
+ if i'<1 || i'>k+k' then a
+ else if i'<=k then MLrel (i+k')
+ else MLrel (i-k)
+ | a -> ast_map_lift permut n a
+ in permut 0
+
+(*s Substitution. [ml_subst e t] substitutes [e] for [Rel 1] in [t].
+ Lifting (of one binder) is done at the same time. *)
+
+let ast_subst e =
+ let rec subst n = function
+ | MLrel i as a ->
+ let i' = i-n in
+ if i'=1 then ast_lift n e
+ else if i'<1 then a
+ else MLrel (i-1)
+ | a -> ast_map_lift subst n a
+ in subst 0
+
+(*s Generalized substitution.
+ [gen_subst v d t] applies to [t] the substitution coded in the
+ [v] array: [(Rel i)] becomes [v.(i-1)]. [d] is the correction applies
+ to [Rel] greater than [Array.length v]. *)
+
+let gen_subst v d t =
+ let rec subst n = function
+ | MLrel i as a ->
+ let i'= i-n in
+ if i' < 1 then a
+ else if i' <= Array.length v then
+ match v.(i'-1) with
+ | None -> MLexn ("UNBOUND " ^ string_of_int i')
+ | Some u -> ast_lift n u
+ else MLrel (i+d)
+ | a -> ast_map_lift subst n a
+ in subst 0 t
+
+(*S Operations concerning lambdas. *)
+
+(*s [collect_lams MLlam(id1,...MLlam(idn,t)...)] returns
+ [[idn;...;id1]] and the term [t]. *)
+
+let collect_lams =
+ let rec collect acc = function
+ | MLlam(id,t) -> collect (id::acc) t
+ | x -> acc,x
+ in collect []
+
+(*s [collect_n_lams] does the same for a precise number of [MLlam]. *)
+
+let collect_n_lams =
+ let rec collect acc n t =
+ if n = 0 then acc,t
+ else match t with
+ | MLlam(id,t) -> collect (id::acc) (n-1) t
+ | _ -> assert false
+ in collect []
+
+(*s [remove_n_lams] just removes some [MLlam]. *)
+
+let rec remove_n_lams n t =
+ if n = 0 then t
+ else match t with
+ | MLlam(_,t) -> remove_n_lams (n-1) t
+ | _ -> assert false
+
+(*s [nb_lams] gives the number of head [MLlam]. *)
+
+let rec nb_lams = function
+ | MLlam(_,t) -> succ (nb_lams t)
+ | _ -> 0
+
+(*s [named_lams] does the converse of [collect_lams]. *)
+
+let rec named_lams ids a = match ids with
+ | [] -> a
+ | id :: ids -> named_lams ids (MLlam (id,a))
+
+(*s The same for a specific identifier (resp. anonymous, dummy) *)
+
+let rec many_lams id a = function
+ | 0 -> a
+ | n -> many_lams id (MLlam (id,a)) (pred n)
+
+let anonym_lams a n = many_lams anonymous a n
+let anonym_tmp_lams a n = many_lams (Tmp anonymous_name) a n
+let dummy_lams a n = many_lams Dummy a n
+
+(*s mixed according to a signature. *)
+
+let rec anonym_or_dummy_lams a = function
+ | [] -> a
+ | Keep :: s -> MLlam(anonymous, anonym_or_dummy_lams a s)
+ | Kill _ :: s -> MLlam(Dummy, anonym_or_dummy_lams a s)
+
+(*S Operations concerning eta. *)
+
+(*s The following function creates [MLrel n;...;MLrel 1] *)
+
+let rec eta_args n =
+ if n = 0 then [] else (MLrel n)::(eta_args (pred n))
+
+(*s Same, but filtered by a signature. *)
+
+let rec eta_args_sign n = function
+ | [] -> []
+ | Keep :: s -> (MLrel n) :: (eta_args_sign (n-1) s)
+ | Kill _ :: s -> eta_args_sign (n-1) s
+
+(*s This one tests [MLrel (n+k); ... ;MLrel (1+k)] *)
+
+let rec test_eta_args_lift k n = function
+ | [] -> n=0
+ | a :: q -> (a = (MLrel (k+n))) && (test_eta_args_lift k (pred n) q)
+
+(*s Computes an eta-reduction. *)
+
+let eta_red e =
+ let ids,t = collect_lams e in
+ let n = List.length ids in
+ if n = 0 then e
+ else match t with
+ | MLapp (f,a) ->
+ let m = List.length a in
+ let ids,body,args =
+ if m = n then
+ [], f, a
+ else if m < n then
+ list_skipn m ids, f, a
+ else (* m > n *)
+ let a1,a2 = list_chop (m-n) a in
+ [], MLapp (f,a1), a2
+ in
+ let p = List.length args in
+ if test_eta_args_lift 0 p args && not (ast_occurs_itvl 1 p body)
+ then named_lams ids (ast_lift (-p) body)
+ else e
+ | _ -> e
+
+(*s Computes all head linear beta-reductions possible in [(t a)].
+ Non-linear head beta-redex become let-in. *)
+
+let rec linear_beta_red a t = match a,t with
+ | [], _ -> t
+ | a0::a, MLlam (id,t) ->
+ (match nb_occur_match t with
+ | 0 -> linear_beta_red a (ast_pop t)
+ | 1 -> linear_beta_red a (ast_subst a0 t)
+ | _ ->
+ let a = List.map (ast_lift 1) a in
+ MLletin (id, a0, linear_beta_red a t))
+ | _ -> MLapp (t, a)
+
+let rec tmp_head_lams = function
+ | MLlam (id, t) -> MLlam (tmp_id id, tmp_head_lams t)
+ | e -> e
+
+(*s Applies a substitution [s] of constants by their body, plus
+ linear beta reductions at modified positions.
+ Moreover, we mark some lambdas as suitable for later linear
+ reduction (this helps the inlining of recursors).
+*)
+
+let rec ast_glob_subst s t = match t with
+ | MLapp ((MLglob ((ConstRef kn) as refe)) as f, a) ->
+ let a = List.map (fun e -> tmp_head_lams (ast_glob_subst s e)) a in
+ (try linear_beta_red a (Refmap.find refe s)
+ with Not_found -> MLapp (f, a))
+ | MLglob ((ConstRef kn) as refe) ->
+ (try Refmap.find refe s with Not_found -> t)
+ | _ -> ast_map (ast_glob_subst s) t
+
+
+(*S Auxiliary functions used in simplification of ML cases. *)
+
+(*s [check_function_branch (r,l,c)] checks if branch [c] can be seen
+ as a function [f] applied to [MLcons(r,l)]. For that it transforms
+ any [MLcons(r,l)] in [MLrel 1] and raises [Impossible] if any
+ variable in [l] occurs outside such a [MLcons] *)
+
+let check_function_branch (r,l,c) =
+ let nargs = List.length l in
+ let rec genrec n = function
+ | MLrel i as c ->
+ let i' = i-n in
+ if i'<1 then c
+ else if i'>nargs then MLrel (i-nargs+1)
+ else raise Impossible
+ | MLcons(_,r',args) when r=r' && (test_eta_args_lift n nargs args) ->
+ MLrel (n+1)
+ | a -> ast_map_lift genrec n a
+ in genrec 0 c
+
+(*s [check_constant_branch (r,l,c)] checks if branch [c] is independent
+ from the pattern [MLcons(r,l)]. For that is raises [Impossible] if any
+ variable in [l] occurs in [c], and otherwise returns [c] lifted to
+ appear like a function with one arg (for uniformity with the
+ branch-as-function optimization) *)
+
+let check_constant_branch (_,l,c) =
+ let n = List.length l in
+ if ast_occurs_itvl 1 n c then raise Impossible;
+ ast_lift (1-n) c
+
+(* The following structure allows to record which element occurred
+ at what position, and then finally return the most frequent
+ element and its positions. *)
+
+let census_add, census_max, census_clean =
+ let h = Hashtbl.create 13 in
+ let clear () = Hashtbl.clear h in
+ let add e i =
+ let l = try Hashtbl.find h e with Not_found -> [] in
+ Hashtbl.replace h e (i::l)
+ in
+ let max e0 =
+ let len = ref 0 and lst = ref [] and elm = ref e0 in
+ Hashtbl.iter
+ (fun e l ->
+ let n = List.length l in
+ if n > !len then begin len := n; lst := l; elm := e end)
+ h;
+ (!elm,!lst)
+ in
+ (add,max,clear)
+
+(* Given an abstraction function [abstr] (one of [check_*_branch]),
+ return the longest possible list of branches that have the
+ same abstraction, along with this abstraction. *)
+
+let factor_branches abstr br =
+ census_clean ();
+ for i = 0 to Array.length br - 1 do
+ try census_add (abstr br.(i)) i with Impossible -> ()
+ done;
+ let br_factor, br_list = census_max MLdummy in
+ if br_list = [] then None
+ else if Array.length br >= 2 && List.length br_list < 2 then None
+ else Some (br_factor, br_list)
+
+(*s [check_generalizable_case] checks if all branches can be seen as the
+ same function [f] applied to the term matched. It is a generalized version
+ of both the identity case optimization and the constant case optimisation
+ ([f] can be a constant function) *)
+
+(* The optimisation [factor_branches check_function_branch] breaks types
+ in some special case. Example: [type 'x a = A].
+ Then [let f = function A -> A] has type ['x a -> 'y a],
+ which is incompatible with the type of [let f x = x].
+ We check first that there isn't such phantom variable in the inductive type
+ we're considering. *)
+
+let check_optim_id br =
+ let (kn,i) =
+ match br.(0) with (ConstructRef (c,_),_,_) -> c | _ -> assert false
+ in
+ let ip = (snd (lookup_ind kn)).ind_packets.(i) in
+ match ip.ip_optim_id_ok with
+ | Some ok -> ok
+ | None ->
+ let tvars =
+ intset_union_map_array (intset_union_map_list type_listvar)
+ ip.ip_types
+ in
+ let ok = (Intset.cardinal tvars = List.length ip.ip_vars) in
+ ip.ip_optim_id_ok <- Some ok;
+ ok
+
+(*s If all branches are functions, try to permut the case and the functions. *)
+
+let rec merge_ids ids ids' = match ids,ids' with
+ | [],l -> l
+ | l,[] -> l
+ | i::ids, i'::ids' ->
+ (if i = Dummy then i' else i) :: (merge_ids ids ids')
+
+let is_exn = function MLexn _ -> true | _ -> false
+
+let rec permut_case_fun br acc =
+ let nb = ref max_int in
+ Array.iter (fun (_,_,t) ->
+ let ids, c = collect_lams t in
+ let n = List.length ids in
+ if (n < !nb) && (not (is_exn c)) then nb := n) br;
+ if !nb = max_int || !nb = 0 then ([],br)
+ else begin
+ let br = Array.copy br in
+ let ids = ref [] in
+ for i = 0 to Array.length br - 1 do
+ let (r,l,t) = br.(i) in
+ let local_nb = nb_lams t in
+ if local_nb < !nb then (* t = MLexn ... *)
+ br.(i) <- (r,l,remove_n_lams local_nb t)
+ else begin
+ let local_ids,t = collect_n_lams !nb t in
+ ids := merge_ids !ids local_ids;
+ br.(i) <- (r,l,permut_rels !nb (List.length l) t)
+ end
+ done;
+ (!ids,br)
+ end
+
+(*S Generalized iota-reduction. *)
+
+(* Definition of a generalized iota-redex: it's a [MLcase(e,_)]
+ with [(is_iota_gen e)=true]. Any generalized iota-redex is
+ transformed into beta-redexes. *)
+
+let rec is_iota_gen = function
+ | MLcons _ -> true
+ | MLcase(_,_,br)-> array_for_all (fun (_,_,t)->is_iota_gen t) br
+ | _ -> false
+
+let constructor_index = function
+ | ConstructRef (_,j) -> pred j
+ | _ -> assert false
+
+let iota_gen br =
+ let rec iota k = function
+ | MLcons (i,r,a) ->
+ let (_,ids,c) = br.(constructor_index r) in
+ let c = List.fold_right (fun id t -> MLlam (id,t)) ids c in
+ let c = ast_lift k c in
+ MLapp (c,a)
+ | MLcase(i,e,br') ->
+ let new_br =
+ Array.map (fun (n,i,c)->(n,i,iota (k+(List.length i)) c)) br'
+ in MLcase(i,e, new_br)
+ | _ -> assert false
+ in iota 0
+
+let is_atomic = function
+ | MLrel _ | MLglob _ | MLexn _ | MLdummy -> true
+ | _ -> false
+
+let is_imm_apply = function MLapp (MLrel 1, _) -> true | _ -> false
+
+(*S The main simplification function. *)
+
+(* Some beta-iota reductions + simplifications. *)
+
+let rec simpl o = function
+ | MLapp (f, []) -> simpl o f
+ | MLapp (f, a) -> simpl_app o (List.map (simpl o) a) (simpl o f)
+ | MLcase (i,e,br) ->
+ let br = Array.map (fun (n,l,t) -> (n,l,simpl o t)) br in
+ simpl_case o i br (simpl o e)
+ | MLletin(Dummy,_,e) -> simpl o (ast_pop e)
+ | MLletin(id,c,e) ->
+ let e = simpl o e in
+ if
+ (is_atomic c) || (is_atomic e) ||
+ (let n = nb_occur_match e in
+ (n = 0 || (n=1 && (is_tmp id || is_imm_apply e || o.opt_lin_let))))
+ then
+ simpl o (ast_subst c e)
+ else
+ MLletin(id, simpl o c, e)
+ | MLfix(i,ids,c) ->
+ let n = Array.length ids in
+ if ast_occurs_itvl 1 n c.(i) then
+ MLfix (i, ids, Array.map (simpl o) c)
+ else simpl o (ast_lift (-n) c.(i)) (* Dummy fixpoint *)
+ | a -> ast_map (simpl o) a
+
+(* invariant : list [a] of arguments is non-empty *)
+
+and simpl_app o a = function
+ | MLapp (f',a') -> simpl_app o (a'@a) f'
+ | MLlam (Dummy,t) ->
+ simpl o (MLapp (ast_pop t, List.tl a))
+ | MLlam (id,t) -> (* Beta redex *)
+ (match nb_occur_match t with
+ | 0 -> simpl o (MLapp (ast_pop t, List.tl a))
+ | 1 when (is_tmp id || o.opt_lin_beta) ->
+ simpl o (MLapp (ast_subst (List.hd a) t, List.tl a))
+ | _ ->
+ let a' = List.map (ast_lift 1) (List.tl a) in
+ simpl o (MLletin (id, List.hd a, MLapp (t, a'))))
+ | MLletin (id,e1,e2) when o.opt_let_app ->
+ (* Application of a letin: we push arguments inside *)
+ MLletin (id, e1, simpl o (MLapp (e2, List.map (ast_lift 1) a)))
+ | MLcase (i,e,br) when o.opt_case_app ->
+ (* Application of a case: we push arguments inside *)
+ let br' =
+ Array.map
+ (fun (n,l,t) ->
+ let k = List.length l in
+ let a' = List.map (ast_lift k) a in
+ (n, l, simpl o (MLapp (t,a')))) br
+ in simpl o (MLcase (i,e,br'))
+ | (MLdummy | MLexn _) as e -> e
+ (* We just discard arguments in those cases. *)
+ | f -> MLapp (f,a)
+
+(* Invariant : all empty matches should now be [MLexn] *)
+
+and simpl_case o i br e =
+ if o.opt_case_iot && (is_iota_gen e) then (* Generalized iota-redex *)
+ simpl o (iota_gen br e)
+ else
+ (* Swap the case and the lam if possible *)
+ let ids,br = if o.opt_case_fun then permut_case_fun br [] else [],br in
+ let n = List.length ids in
+ if n <> 0 then
+ simpl o (named_lams ids (MLcase (i,ast_lift n e, br)))
+ else
+ (* Does a term [f] exist such that many branches are [(f e)] ? *)
+ let opt1 =
+ if o.opt_case_idr && (o.opt_case_idg || check_optim_id br) then
+ factor_branches check_function_branch br
+ else None
+ in
+ (* Detect common constant branches. Often a particular case of
+ branch-as-function optim, but not always (e.g. A->A|B->A) *)
+ let opt2 =
+ if opt1 = None && o.opt_case_cst then
+ factor_branches check_constant_branch br
+ else opt1
+ in
+ match opt2 with
+ | Some (f,ints) when List.length ints = Array.length br ->
+ (* if all branches have been factorized, we remove the match *)
+ simpl o (MLletin (Tmp anonymous_name, e, f))
+ | Some (f,ints) ->
+ let ci = if ast_occurs 1 f then BranchFun ints else BranchCst ints
+ in MLcase ((fst i,ci), e, br)
+ | None -> MLcase (i, e, br)
+
+(*S Local prop elimination. *)
+(* We try to eliminate as many [prop] as possible inside an [ml_ast]. *)
+
+(*s In a list, it selects only the elements corresponding to a [Keep]
+ in the boolean list [l]. *)
+
+let rec select_via_bl l args = match l,args with
+ | [],_ -> args
+ | Keep::l,a::args -> a :: (select_via_bl l args)
+ | Kill _::l,a::args -> select_via_bl l args
+ | _ -> assert false
+
+(*s [kill_some_lams] removes some head lambdas according to the signature [bl].
+ This list is build on the identifier list model: outermost lambda
+ is on the right.
+ [Rels] corresponding to removed lambdas are supposed not to occur, and
+ the other [Rels] are made correct via a [gen_subst].
+ Output is not directly a [ml_ast], compose with [named_lams] if needed. *)
+
+let kill_some_lams bl (ids,c) =
+ let n = List.length bl in
+ let n' = List.fold_left (fun n b -> if b=Keep then (n+1) else n) 0 bl in
+ if n = n' then ids,c
+ else if n' = 0 then [],ast_lift (-n) c
+ else begin
+ let v = Array.make n None in
+ let rec parse_ids i j = function
+ | [] -> ()
+ | Keep :: l -> v.(i) <- Some (MLrel j); parse_ids (i+1) (j+1) l
+ | Kill _ :: l -> parse_ids (i+1) j l
+ in parse_ids 0 1 bl;
+ select_via_bl bl ids, gen_subst v (n'-n) c
+ end
+
+(*s [kill_dummy_lams] uses the last function to kill the lambdas corresponding
+ to a [dummy_name]. It can raise [Impossible] if there is nothing to do, or
+ if there is no lambda left at all. *)
+
+let kill_dummy_lams c =
+ let ids,c = collect_lams c in
+ let bl = List.map sign_of_id ids in
+ if (List.mem Keep bl) && (List.exists isKill bl) then
+ let ids',c = kill_some_lams bl (ids,c) in
+ ids, named_lams ids' c
+ else raise Impossible
+
+(*s [eta_expansion_sign] takes a function [fun idn ... id1 -> c]
+ and a signature [s] and builds a eta-long version. *)
+
+(* For example, if [s = [Keep;Keep;Kill Prop;Keep]] then the output is :
+ [fun idn ... id1 x x _ x -> (c' 4 3 __ 1)] with [c' = lift 4 c] *)
+
+let eta_expansion_sign s (ids,c) =
+ let rec abs ids rels i = function
+ | [] ->
+ let a = List.rev_map (function MLrel x -> MLrel (i-x) | a -> a) rels
+ in ids, MLapp (ast_lift (i-1) c, a)
+ | Keep :: l -> abs (anonymous :: ids) (MLrel i :: rels) (i+1) l
+ | Kill _ :: l -> abs (Dummy :: ids) (MLdummy :: rels) (i+1) l
+ in abs ids [] 1 s
+
+(*s If [s = [b1; ... ; bn]] then [case_expunge] decomposes [e]
+ in [n] lambdas (with eta-expansion if needed) and removes all dummy lambdas
+ corresponding to [Del] in [s]. *)
+
+let case_expunge s e =
+ let m = List.length s in
+ let n = nb_lams e in
+ let p = if m <= n then collect_n_lams m e
+ else eta_expansion_sign (list_skipn n s) (collect_lams e) in
+ kill_some_lams (List.rev s) p
+
+(*s [term_expunge] takes a function [fun idn ... id1 -> c]
+ and a signature [s] and remove dummy lams. The difference
+ with [case_expunge] is that we here leave one dummy lambda
+ if all lambdas are logical dummy and the target language is strict. *)
+
+let term_expunge s (ids,c) =
+ if s = [] then c
+ else
+ let ids,c = kill_some_lams (List.rev s) (ids,c) in
+ if ids = [] && lang () <> Haskell && List.mem (Kill Kother) s then
+ MLlam (Dummy, ast_lift 1 c)
+ else named_lams ids c
+
+(*s [kill_dummy_args ids t0 t] looks for occurences of [t0] in [t] and
+ purge the args of [t0] corresponding to a [dummy_name].
+ It makes eta-expansion if needed. *)
+
+let kill_dummy_args ids t0 t =
+ let m = List.length ids in
+ let bl = List.rev_map sign_of_id ids in
+ let rec killrec n = function
+ | MLapp(e, a) when e = ast_lift n t0 ->
+ let k = max 0 (m - (List.length a)) in
+ let a = List.map (killrec n) a in
+ let a = List.map (ast_lift k) a in
+ let a = select_via_bl bl (a @ (eta_args k)) in
+ named_lams (list_firstn k ids) (MLapp (ast_lift k e, a))
+ | e when e = ast_lift n t0 ->
+ let a = select_via_bl bl (eta_args m) in
+ named_lams ids (MLapp (ast_lift m e, a))
+ | e -> ast_map_lift killrec n e
+ in killrec 0 t
+
+(*s The main function for local [dummy] elimination. *)
+
+let rec kill_dummy = function
+ | MLfix(i,fi,c) ->
+ (try
+ let ids,c = kill_dummy_fix i c in
+ ast_subst (MLfix (i,fi,c)) (kill_dummy_args ids (MLrel 1) (MLrel 1))
+ with Impossible -> MLfix (i,fi,Array.map kill_dummy c))
+ | MLapp (MLfix (i,fi,c),a) ->
+ let a = List.map kill_dummy a in
+ (try
+ let ids,c = kill_dummy_fix i c in
+ let fake = MLapp (MLrel 1, List.map (ast_lift 1) a) in
+ let fake' = kill_dummy_args ids (MLrel 1) fake in
+ ast_subst (MLfix (i,fi,c)) fake'
+ with Impossible -> MLapp(MLfix(i,fi,Array.map kill_dummy c),a))
+ | MLletin(id, MLfix (i,fi,c),e) ->
+ (try
+ let ids,c = kill_dummy_fix i c in
+ let e = kill_dummy (kill_dummy_args ids (MLrel 1) e) in
+ MLletin(id, MLfix(i,fi,c),e)
+ with Impossible ->
+ MLletin(id, MLfix(i,fi,Array.map kill_dummy c),kill_dummy e))
+ | MLletin(id,c,e) ->
+ (try
+ let ids,c = kill_dummy_lams (kill_dummy_hd c) in
+ let e = kill_dummy (kill_dummy_args ids (MLrel 1) e) in
+ let c = eta_red (kill_dummy c) in
+ if is_atomic c then ast_subst c e else MLletin (id, c, e)
+ with Impossible -> MLletin(id,kill_dummy c,kill_dummy e))
+ | a -> ast_map kill_dummy a
+
+(* Similar function, but acting only on head lambdas and let-ins *)
+
+and kill_dummy_hd = function
+ | MLlam(id,e) -> MLlam(id, kill_dummy_hd e)
+ | MLletin(id,c,e) ->
+ (try
+ let ids,c = kill_dummy_lams (kill_dummy_hd c) in
+ let e = kill_dummy_hd (kill_dummy_args ids (MLrel 1) e) in
+ let c = eta_red (kill_dummy c) in
+ if is_atomic c then ast_subst c e else MLletin (id, c, e)
+ with Impossible -> MLletin(id,kill_dummy c,kill_dummy_hd e))
+ | a -> a
+
+and kill_dummy_fix i c =
+ let n = Array.length c in
+ let ids,ci = kill_dummy_lams (kill_dummy_hd c.(i)) in
+ let c = Array.copy c in c.(i) <- ci;
+ for j = 0 to (n-1) do
+ c.(j) <- kill_dummy (kill_dummy_args ids (MLrel (n-i)) c.(j))
+ done;
+ ids,c
+
+(*s Putting things together. *)
+
+let normalize a =
+ let o = optims () in
+ let rec norm a =
+ let a' = if o.opt_kill_dum then kill_dummy (simpl o a) else simpl o a in
+ if a = a' then a else norm a'
+ in norm a
+
+(*S Special treatment of fixpoint for pretty-printing purpose. *)
+
+let general_optimize_fix f ids n args m c =
+ let v = Array.make n 0 in
+ for i=0 to (n-1) do v.(i)<-i done;
+ let aux i = function
+ | MLrel j when v.(j-1)>=0 ->
+ if ast_occurs (j+1) c then raise Impossible else v.(j-1)<-(-i-1)
+ | _ -> raise Impossible
+ in list_iter_i aux args;
+ let args_f = List.rev_map (fun i -> MLrel (i+m+1)) (Array.to_list v) in
+ let new_f = anonym_tmp_lams (MLapp (MLrel (n+m+1),args_f)) m in
+ let new_c = named_lams ids (normalize (MLapp ((ast_subst new_f c),args))) in
+ MLfix(0,[|f|],[|new_c|])
+
+let optimize_fix a =
+ if not (optims()).opt_fix_fun then a
+ else
+ let ids,a' = collect_lams a in
+ let n = List.length ids in
+ if n = 0 then a
+ else match a' with
+ | MLfix(_,[|f|],[|c|]) ->
+ let new_f = MLapp (MLrel (n+1),eta_args n) in
+ let new_c = named_lams ids (normalize (ast_subst new_f c))
+ in MLfix(0,[|f|],[|new_c|])
+ | MLapp(a',args) ->
+ let m = List.length args in
+ (match a' with
+ | MLfix(_,_,_) when
+ (test_eta_args_lift 0 n args) && not (ast_occurs_itvl 1 m a')
+ -> a'
+ | MLfix(_,[|f|],[|c|]) ->
+ (try general_optimize_fix f ids n args m c
+ with Impossible -> a)
+ | _ -> a)
+ | _ -> a
+
+(*S Inlining. *)
+
+(* Utility functions used in the decision of inlining. *)
+
+let rec ml_size = function
+ | MLapp(t,l) -> List.length l + ml_size t + ml_size_list l
+ | MLlam(_,t) -> 1 + ml_size t
+ | MLcons(_,_,l) -> ml_size_list l
+ | MLcase(_,t,pv) ->
+ 1 + ml_size t + (Array.fold_right (fun (_,_,t) a -> a + ml_size t) pv 0)
+ | MLfix(_,_,f) -> ml_size_array f
+ | MLletin (_,_,t) -> ml_size t
+ | MLmagic t -> ml_size t
+ | _ -> 0
+
+and ml_size_list l = List.fold_left (fun a t -> a + ml_size t) 0 l
+
+and ml_size_array l = Array.fold_left (fun a t -> a + ml_size t) 0 l
+
+let is_fix = function MLfix _ -> true | _ -> false
+
+let rec is_constr = function
+ | MLcons _ -> true
+ | MLlam(_,t) -> is_constr t
+ | _ -> false
+
+(*s Strictness *)
+
+(* A variable is strict if the evaluation of the whole term implies
+ the evaluation of this variable. Non-strict variables can be found
+ behind Match, for example. Expanding a term [t] is a good idea when
+ it begins by at least one non-strict lambda, since the corresponding
+ argument to [t] might be unevaluated in the expanded code. *)
+
+exception Toplevel
+
+let lift n l = List.map ((+) n) l
+
+let pop n l = List.map (fun x -> if x<=n then raise Toplevel else x-n) l
+
+(* This function returns a list of de Bruijn indices of non-strict variables,
+ or raises [Toplevel] if it has an internal non-strict variable.
+ In fact, not all variables are checked for strictness, only the ones which
+ de Bruijn index is in the candidates list [cand]. The flag [add] controls
+ the behaviour when going through a lambda: should we add the corresponding
+ variable to the candidates? We use this flag to check only the external
+ lambdas, those that will correspond to arguments. *)
+
+let rec non_stricts add cand = function
+ | MLlam (id,t) ->
+ let cand = lift 1 cand in
+ let cand = if add then 1::cand else cand in
+ pop 1 (non_stricts add cand t)
+ | MLrel n ->
+ List.filter ((<>) n) cand
+ | MLapp (t,l)->
+ let cand = non_stricts false cand t in
+ List.fold_left (non_stricts false) cand l
+ | MLcons (_,_,l) ->
+ List.fold_left (non_stricts false) cand l
+ | MLletin (_,t1,t2) ->
+ let cand = non_stricts false cand t1 in
+ pop 1 (non_stricts add (lift 1 cand) t2)
+ | MLfix (_,i,f)->
+ let n = Array.length i in
+ let cand = lift n cand in
+ let cand = Array.fold_left (non_stricts false) cand f in
+ pop n cand
+ | MLcase (_,t,v) ->
+ (* The only interesting case: for a variable to be non-strict, *)
+ (* it is sufficient that it appears non-strict in at least one branch, *)
+ (* so we make an union (in fact a merge). *)
+ let cand = non_stricts false cand t in
+ Array.fold_left
+ (fun c (_,i,t)->
+ let n = List.length i in
+ let cand = lift n cand in
+ let cand = pop n (non_stricts add cand t) in
+ Sort.merge (<=) cand c) [] v
+ (* [merge] may duplicates some indices, but I don't mind. *)
+ | MLmagic t ->
+ non_stricts add cand t
+ | _ ->
+ cand
+
+(* The real test: we are looking for internal non-strict variables, so we start
+ with no candidates, and the only positive answer is via the [Toplevel]
+ exception. *)
+
+let is_not_strict t =
+ try let _ = non_stricts true [] t in false
+ with Toplevel -> true
+
+(*s Inlining decision *)
+
+(* [inline_test] answers the following question:
+ If we could inline [t] (the user said nothing special),
+ should we inline ?
+
+ We expand small terms with at least one non-strict
+ variable (i.e. a variable that may not be evaluated).
+
+ Futhermore we don't expand fixpoints.
+
+ Moreover, as mentionned by X. Leroy (bug #2241),
+ inling a constant from inside an opaque module might
+ break types. To avoid that, we require below that
+ both [r] and its body are globally visible. This isn't
+ fully satisfactory, since [r] might not be visible (functor),
+ and anyway it might be interesting to inline [r] at least
+ inside its own structure. But to be safe, we adopt this
+ restriction for the moment.
+*)
+
+open Declarations
+
+let inline_test r t =
+ if not (auto_inline ()) then false
+ else
+ let c = match r with ConstRef c -> c | _ -> assert false in
+ let body = try (Global.lookup_constant c).const_body with _ -> None in
+ if body = None then false
+ else
+ let t1 = eta_red t in
+ let t2 = snd (collect_lams t1) in
+ not (is_fix t2) && ml_size t < 12 && is_not_strict t
+
+let con_of_string s =
+ let null = empty_dirpath in
+ match repr_dirpath (dirpath_of_string s) with
+ | id :: d -> make_con (MPfile (make_dirpath d)) null (label_of_id id)
+ | [] -> assert false
+
+let manual_inline_set =
+ List.fold_right (fun x -> Cset.add (con_of_string x))
+ [ "Coq.Init.Wf.well_founded_induction_type";
+ "Coq.Init.Wf.well_founded_induction";
+ "Coq.Init.Wf.Acc_iter";
+ "Coq.Init.Wf.Fix_F";
+ "Coq.Init.Wf.Fix";
+ "Coq.Init.Datatypes.andb";
+ "Coq.Init.Datatypes.orb";
+ "Coq.Init.Logic.eq_rec_r";
+ "Coq.Init.Logic.eq_rect_r";
+ "Coq.Init.Specif.proj1_sig";
+ ]
+ Cset.empty
+
+let manual_inline = function
+ | ConstRef c -> Cset.mem c manual_inline_set
+ | _ -> false
+
+(* If the user doesn't say he wants to keep [t], we inline in two cases:
+ \begin{itemize}
+ \item the user explicitly requests it
+ \item [expansion_test] answers that the inlining is a good idea, and
+ we are free to act (AutoInline is set)
+ \end{itemize} *)
+
+let inline r t =
+ not (to_keep r) (* The user DOES want to keep it *)
+ && not (is_inline_custom r)
+ && (to_inline r (* The user DOES want to inline it *)
+ || (lang () <> Haskell && not (is_projection r) &&
+ (is_recursor r || manual_inline r || inline_test r t)))
+
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