(*  Title:      HOL/Boogie/Tools/boogie_loader.ML

     Author:     Sascha Boehme, TU Muenchen

 Loading and interpreting Boogie-generated files.

 *)

 signature BOOGIE_LOADER =

 sig

   val load_b2i: bool -> (string * int) list -> Path.T -> theory -> theory

 end

 structure Boogie_Loader: BOOGIE_LOADER =

 struct

 fun log verbose text args x =

   if verbose andalso not (null args)

   then (Pretty.writeln (Pretty.big_list text (map Pretty.str args)); x)

   else x

 val isabelle_name =

   let 

     fun purge s = if Symbol.is_letter s orelse Symbol.is_digit s then s else

       (case s of

         "." => "_o_"

       | "_" => "_n_"

       | "$" => "_S_"

       | "@" => "_G_"

       | "#" => "_H_"

       | "^" => "_T_"

       | _   => ("_" ^ string_of_int (ord s) ^ "_"))

   in prefix "b_" o translate_string purge end

 fun drop_underscore s =

   try (unsuffix "_") s

   |> Option.map drop_underscore

   |> the_default s

 val short_name =

   translate_string (fn s => if Symbol.is_letdig s then s else "") #>

   drop_underscore

 (* these prefixes must be distinct: *)

 val var_prefix = "V_"

 val label_prefix = "L_"

 val position_prefix = "P_"

 val no_label_name = label_prefix ^ "unknown"

 fun label_name line col =

   if line = 0 orelse col = 0 then no_label_name

   else label_prefix ^ string_of_int line ^ "_" ^ string_of_int col

 fun mk_syntax name i =

   let

     val syn = Syntax_Ext.escape name

     val args = space_implode ",/ " (replicate i "_")

   in

     if i = 0 then Mixfix (syn, [], 1000)

     else Mixfix (syn ^ "()'(/" ^ args ^ "')", replicate i 0, 1000)

   end

 datatype attribute_value = StringValue of string | TermValue of term

 local

   fun lookup_type_name thy name arity =

     let val intern = Sign.intern_type thy name

     in

       if Sign.declared_tyname thy intern

       then

         if Sign.arity_number thy intern = arity then SOME intern

         else error ("Boogie: type already declared with different arity: " ^

           quote name)

       else NONE

     end

   fun log_new bname name = bname ^ " (as " ^ name ^ ")"

   fun log_ex bname name = "[" ^ bname ^ " has already been declared as " ^

     name ^ "]"

   fun declare (name, arity) thy =

     let val isa_name = isabelle_name name

     in

       (case lookup_type_name thy isa_name arity of

         SOME type_name => (((name, type_name), log_ex name type_name), thy)

       | NONE =>

           let

             val args = map (rpair dummyS) (Name.invents Name.context "'a" arity)

             val (T, thy') =

               Typedecl.typedecl_global (Binding.name isa_name, args, mk_syntax name arity) thy

             val type_name = fst (Term.dest_Type T)

           in (((name, type_name), log_new name type_name), thy') end)

     end

 in

 fun declare_types verbose tys =

   fold_map declare tys #>> split_list #-> (fn (tds, logs) =>

   log verbose "Declared types:" logs #>

   rpair (Symtab.make tds))

 end

 local

   fun maybe_builtin T =

     let

       fun const name = SOME (Const (name, T))

       fun const2_abs name =

         let val U = Term.domain_type T

         in

           SOME (Abs (Name.uu, U, Abs (Name.uu, U,

             Const (name, T) $ Bound 0 $ Bound 1)))

         end

       fun choose builtin =

         (case builtin of

           "bvnot" => const @{const_name bitNOT}

         | "bvand" => const @{const_name bitAND}

         | "bvor" => const @{const_name bitOR}

         | "bvxor" => const @{const_name bitXOR}

         | "bvadd" => const @{const_name plus}

         | "bvneg" => const @{const_name uminus}

         | "bvsub" => const @{const_name minus}

         | "bvmul" => const @{const_name times}

 (* FIXME:

         | "bvudiv" => const @{const_name div}

         | "bvurem" => const @{const_name mod}

         | "bvsdiv" => const @{const_name sdiv}

         | "bvsrem" => const @{const_name srem}

         | "bvshl" => const @{const_name bv_shl}

         | "bvlshr" => const @{const_name bv_lshr}

         | "bvashr" => const @{const_name bv_ashr}

 *)

         | "bvult" => const @{const_name less}

         | "bvule" => const @{const_name less_eq}

         | "bvugt" => const2_abs @{const_name less}

         | "bvuge" => const2_abs @{const_name less_eq}

         | "bvslt" => const @{const_name word_sless}

         | "bvsle" => const @{const_name word_sle}

         | "bvsgt" => const2_abs @{const_name word_sless}

         | "bvsge" => const2_abs @{const_name word_sle}

         | "zero_extend" => const @{const_name ucast}

         | "sign_extend" => const @{const_name scast}

         | _ => NONE)

       fun is_builtin att =

         (case att of

           ("bvbuiltin", [StringValue builtin]) => choose builtin

         | ("bvint", [StringValue "ITE"]) => const @{const_name If}

         | _ => NONE)

     in get_first is_builtin end

   fun lookup_const thy name T =

     let val intern = Sign.intern_const thy name

     in

       if Sign.declared_const thy intern

       then

         if Sign.typ_instance thy (T, Sign.the_const_type thy intern)

         then SOME (Const (intern, T))

         else error ("Boogie: function already declared with different type: " ^

           quote name)

       else NONE

     end

   fun log_term thy t = Syntax.string_of_term_global thy t

   fun log_new thy name t = name ^ " (as " ^ log_term thy t ^ ")"

   fun log_ex thy name t = "[" ^ name ^ " has already been declared as " ^

     log_term thy t ^ "]"

   fun log_builtin thy name t = "[" ^ name ^ " has been identified as " ^

     log_term thy t ^ "]"

   fun declare' name isa_name T arity atts thy =

     (case lookup_const thy isa_name T of

       SOME t => (((name, t), log_ex thy name t), thy)

     | NONE =>

         (case maybe_builtin T atts of

           SOME t => (((name, t), log_builtin thy name t), thy)

         | NONE =>

             thy

             |> Sign.declare_const_global ((Binding.name isa_name, T),

                  mk_syntax name arity)

             |> (fn (t, thy') => (((name, t), log_new thy' name t), thy'))))

   fun declare (name, ((Ts, T), atts)) =

     declare' name (isabelle_name name) (Ts ---> T) (length Ts) atts

   fun uniques fns fds =

     let

       fun is_unique (name, (([], _), atts)) =

             (case AList.lookup (op =) atts "unique" of

               SOME _ => Symtab.lookup fds name

             | NONE => NONE)

         | is_unique _ = NONE

       fun mk_unique_axiom T ts =

         Const (@{const_name distinct}, HOLogic.listT T --> @{typ bool}) $

           HOLogic.mk_list T ts

     in

       map_filter is_unique fns

       |> map (swap o Term.dest_Const)

       |> AList.group (op =)

       |> map (fn (T, ns) => mk_unique_axiom T (map (Const o rpair T) ns))

     end

 in

 fun declare_functions verbose fns =

   fold_map declare fns #>> split_list #-> (fn (fds, logs) =>

   log verbose "Loaded constants:" logs #>

   rpair (` (uniques fns) (Symtab.make fds)))

 end

 local

   fun name_axioms axs =

     let fun mk_name idx = "axiom_" ^ string_of_int (idx + 1)

     in map_index (fn (idx, t) => (mk_name idx, HOLogic.mk_Trueprop t)) axs end

   datatype kind = Unused of thm | Used of thm | New of string

   fun mark (name, t) axs =

     (case Termtab.lookup axs t of

       SOME (Unused thm) => Termtab.update (t, Used thm) axs

     | NONE => Termtab.update (t, New name) axs

     | SOME _ => axs)

   val sort_fst_str = sort (prod_ord fast_string_ord (K EQUAL)) 

   fun split_list_kind thy axs =

     let

       fun split (_, Used thm) (used, new) = (thm :: used, new)

         | split (t, New name) (used, new) = (used, (name, t) :: new)

         | split (_, Unused thm) (used, new) =

            (warning (Pretty.str_of

              (Pretty.big_list "This background axiom has not been loaded:"

                [Display.pretty_thm_global thy thm]));

             (used, new))

     in apsnd sort_fst_str (fold split axs ([], [])) end

   fun mark_axioms thy axs =

     Boogie_Axioms.get (Proof_Context.init_global thy)

     |> Termtab.make o map (fn thm => (Thm.prop_of thm, Unused thm))

     |> fold mark axs

     |> split_list_kind thy o Termtab.dest

 in

 fun add_axioms verbose axs thy =

   let

     val (used, new) = mark_axioms thy (name_axioms axs)

   in

     thy

     |> fold_map (fn (n, t) => Specification.axiom ((Binding.name n, []), t)) new

     |-> Context.theory_map o fold (Boogie_Axioms.add_thm o Drule.export_without_context)

     |> log verbose "The following axioms were added:" (map fst new)

     |> (fn thy' => log verbose "The following axioms already existed:"

          (map (Display.string_of_thm_global thy') used) thy')

   end

 end

 local

   fun burrow_distinct eq f xs =

     let

       val ys = distinct eq xs

       val tab = ys ~~ f ys

     in map (the o AList.lookup eq tab) xs end

   fun indexed names =

     let

       val dup = member (op =) (duplicates (op =) (map fst names))

       fun make_name (n, i) = n ^ (if dup n then "_" ^ string_of_int i else "")

     in map make_name names end

   fun rename idx_names =

     idx_names

     |> burrow_fst (burrow_distinct (op =)

          (map short_name #> ` (duplicates (op =)) #-> Name.variant_list))

     |> indexed

 in

 fun add_vcs verbose vcs thy =

   let val vcs' = burrow_fst rename vcs

   in

     thy

     |> Boogie_VCs.set vcs'

     |> log verbose "The following verification conditions were loaded:"

          (map fst vcs')

   end

 end

 local

   fun mk_bitT i T =

     if i = 0

     then Type (@{type_name "Numeral_Type.bit0"}, [T])

     else Type (@{type_name "Numeral_Type.bit1"}, [T])

   fun mk_binT size = 

     if size = 0 then @{typ "Numeral_Type.num0"}

     else if size = 1 then @{typ "Numeral_Type.num1"}

     else let val (q, r) = Integer.div_mod size 2 in mk_bitT r (mk_binT q) end

 in

 fun mk_wordT size =

   if size >= 0 then Type (@{type_name "word"}, [mk_binT size])

   else raise TYPE ("mk_wordT: " ^ quote (string_of_int size), [], [])

 end

 local

   fun dest_binT T =

     (case T of

       Type (@{type_name "Numeral_Type.num0"}, _) => 0

     | Type (@{type_name "Numeral_Type.num1"}, _) => 1

     | Type (@{type_name "Numeral_Type.bit0"}, [T]) => 2 * dest_binT T

     | Type (@{type_name "Numeral_Type.bit1"}, [T]) => 1 + 2 * dest_binT T

     | _ => raise TYPE ("dest_binT", [T], []))

 in

 val dest_wordT = (fn

     Type (@{type_name "word"}, [T]) => dest_binT T

   | T => raise TYPE ("dest_wordT", [T], []))

 end

 fun mk_arrayT (Ts, T) = Type (@{type_name "fun"}, [HOLogic.mk_tupleT Ts, T])

 datatype token = Token of string | Newline | EOF

 fun tokenize path =

   let

     fun blank c = (c = #" " orelse c = #"\t" orelse c = #"\n" orelse c = #"\r")

     fun split line (i, tss) = (i + 1,

       map (pair i) (map Token (String.tokens blank line) @ [Newline]) :: tss)

   in apsnd (flat o rev) (File.fold_lines split path (1, [])) end

 fun stopper i = Scan.stopper (K (i, EOF)) (fn (_, EOF) => true | _ => false)

 fun scan_err msg [] = "Boogie (at end of input): " ^ msg

   | scan_err msg ((i, _) :: _) = "Boogie (at line " ^ string_of_int i ^ "): " ^

       msg

 fun scan_fail msg = Scan.fail_with (scan_err msg)

 fun finite scan path =

   let val (i, ts) = tokenize path

   in

     (case Scan.error (Scan.finite (stopper i) scan) ts of

       (x, []) => x

     | (_, ts') => error (scan_err "unparsed input" ts'))

   end

 fun read_int' s = (case read_int (raw_explode s) of (i, []) => SOME i | _ => NONE)

 fun $$$ s = Scan.one (fn (_, Token s') => s = s' | _ => false)

 fun str st = Scan.some (fn (_, Token s) => SOME s | _ => NONE) st

 fun num st = Scan.some (fn (_, Token s) => read_int' s | _ => NONE) st

 fun scan_line key scan =

   $$$ key |-- scan --| Scan.one (fn (_, Newline) => true | _ => false)

 fun scan_line' key = scan_line key (Scan.succeed ())

 fun scan_count scan i =

   if i > 0 then scan ::: scan_count scan (i - 1) else Scan.succeed []

 fun scan_lookup kind tab key =

   (case Symtab.lookup tab key of

     SOME value => Scan.succeed value

   | NONE => scan_fail ("undefined " ^ kind ^ ": " ^ quote key))

 fun typ tds =

   let

     fun tp st =

      (scan_line' "bool" >> K @{typ bool} ||

       scan_line' "int" >> K @{typ int} ||

       scan_line "bv" num >> mk_wordT ||

       scan_line "type-con" (str -- num) :|-- (fn (name, arity) =>

         scan_lookup "type constructor" tds name -- scan_count tp arity >>

         Type) ||

       scan_line "array" num :|-- (fn arity =>

         scan_count tp (arity - 1) -- tp >> mk_arrayT) ||

       scan_fail "illegal type") st

   in tp end

 local

   fun mk_nary _ t [] = t

     | mk_nary f _ ts = uncurry (fold_rev f) (split_last ts)

   fun mk_list T = HOLogic.mk_list T

   fun mk_distinct T ts =

     Const (@{const_name distinct}, HOLogic.listT T --> @{typ bool}) $

       mk_list T ts

   fun quant name f = scan_line name (num -- num -- num) >> pair f

   val quants =

     quant "forall" HOLogic.all_const ||

     quant "exists" HOLogic.exists_const ||

     scan_fail "illegal quantifier kind"

   fun mk_quant q (n, T) t = q T $ Term.absfree (n, T, t)

   val patternT = @{typ "SMT.pattern"}

   fun mk_pattern _ [] = raise TERM ("mk_pattern", [])

     | mk_pattern n ts =

         let fun mk_pat t = Const (n, Term.fastype_of t --> patternT) $ t

         in mk_list patternT (map mk_pat ts) end

   fun patt n c scan =

     scan_line n num :|-- scan_count scan >> (mk_pattern c)

   fun pattern scan =

     patt "pat" @{const_name "SMT.pat"} scan ||

     patt "nopat" @{const_name "SMT.nopat"} scan ||

     scan_fail "illegal pattern kind"

   fun mk_trigger [] t = t

     | mk_trigger ps t =

         @{term "SMT.trigger"} $ mk_list @{typ "SMT.pattern list"} ps $ t

   fun make_label (line, col) = Free (label_name line col, @{typ bool})

   fun labelled_by kind pos t = kind $ make_label pos $ t

   fun label offset =

     $$$ "pos" |-- num -- num >> (fn (line, col) =>

       if label_name line col = no_label_name then I

       else labelled_by @{term block_at} (line - offset, col)) ||

     $$$ "neg" |-- num -- num >> (fn (line, col) =>

       labelled_by @{term assert_at} (line - offset, col)) ||

     scan_fail "illegal label kind"

   fun mk_store ((m, k), v) =

     let

       val mT = Term.fastype_of m and kT = Term.fastype_of k

       val vT = Term.fastype_of v

     in Const (@{const_name fun_upd}, mT --> kT --> vT --> mT) $ m $ k $ v end

   fun mk_extract ((msb, lsb), t) =

     let

       val dT = Term.fastype_of t and rT = mk_wordT (msb - lsb)

       val nT = @{typ nat}

       val mk_nat_num = HOLogic.mk_number @{typ nat}

     in Const (@{const_name slice}, [nT, dT] ---> rT) $ mk_nat_num lsb $ t end

   fun mk_concat (t1, t2) =

     let

       val T1 = Term.fastype_of t1 and T2 = Term.fastype_of t2

       val U = mk_wordT (dest_wordT T1 + dest_wordT T2)

     in Const (@{const_name word_cat}, [T1, T2] ---> U) $ t1 $ t2 end

   fun unique_labels t =

     let

       fun names_of (@{term assert_at} $ Free (n, _) $ t) = cons n #> names_of t

         | names_of (t $ u) = names_of t #> names_of u

         | names_of (Abs (_, _, t)) = names_of t

         | names_of _ = I

       val nctxt = Name.make_context (duplicates (op =) (names_of t []))

       fun fresh (i, nctxt) = (position_prefix ^ string_of_int i, (i+1, nctxt))

       fun renamed n (i, nctxt) = Name.variant n nctxt ||> pair i

       fun mk_label (name, t) = @{term assert_at} $ Free (name, @{typ bool}) $ t

       fun unique t =

         (case t of

           @{term assert_at} $ Free (n, _) $ u =>

             if n = no_label_name

             then fresh ##>> unique u #>> mk_label

             else renamed n ##>> unique u #>> mk_label

         | u1 $ u2 => unique u1 ##>> unique u2 #>> (op $)

         | Abs (n, T, u) => unique u #>> (fn u' => Abs (n, T, u'))

         | _ => pair t)

     in fst (unique t (1, nctxt)) end

   val var_name = str >> prefix var_prefix

   val dest_var_name = unprefix var_prefix

   fun rename_variables t =

     let

       fun short_var_name n = short_name (dest_var_name n)

       val all_names = Term.add_free_names t []

       val (names, nctxt) =

         all_names

         |> map_filter (try (fn n => (n, short_var_name n)))

         |> split_list

         ||>> (fn names => fold_map Name.variant names (Name.make_context all_names))

         |>> Symtab.make o (op ~~)

       fun rename_free n = the_default n (Symtab.lookup names n)

       fun rename_abs n = Name.variant (short_var_name n)

       fun rename _ (Free (n, T)) = Free (rename_free n, T)

         | rename nctxt (Abs (n, T, t)) =

             let val (n', nctxt') = rename_abs n nctxt

             in Abs (n', T, rename nctxt' t) end

         | rename nctxt (t $ u) = rename nctxt t $ rename nctxt u

         | rename _ t = t

     in rename nctxt t end

 in

 fun expr offset tds fds =

   let

     fun binop t (u1, u2) = t $ u1 $ u2

     fun binexp s f = scan_line' s |-- exp -- exp >> f

     and exp st =

      (scan_line' "true" >> K @{term True} ||

       scan_line' "false" >> K @{term False} ||

       scan_line' "not" |-- exp >> HOLogic.mk_not ||

       scan_line "and" num :|-- scan_count exp >> 

         mk_nary (curry HOLogic.mk_conj) @{term True} ||

       scan_line "or" num :|-- scan_count exp >>

         mk_nary (curry HOLogic.mk_disj) @{term False} ||

       scan_line' "ite" |-- exp -- exp -- exp >> (fn ((c, t1), t2) =>

         let val T = Term.fastype_of t1

         in

           Const (@{const_name If}, [@{typ bool}, T, T] ---> T) $ c $ t1 $ t2

         end) ||

       binexp "implies" (binop @{term HOL.implies}) ||

       scan_line "distinct" num :|-- scan_count exp >>

         (fn [] => @{term True}

           | ts as (t :: _) => mk_distinct (Term.fastype_of t) ts) ||

       binexp "=" HOLogic.mk_eq ||

       scan_line "var" var_name -- typ tds >> Free ||

       scan_line "fun" (str -- num) :|-- (fn (name, arity) =>

         scan_lookup "constant" fds name -- scan_count exp arity >>

         Term.list_comb) ||

       quants :|-- (fn (q, ((n, k), i)) =>

         scan_count (scan_line "var" var_name -- typ tds) n --

         scan_count (pattern exp) k --

         scan_count (attribute offset tds fds) i --

         exp >> (fn (((vs, ps), _), t) =>

           fold_rev (mk_quant q) vs (mk_trigger ps t))) ||

       scan_line "label" (label offset) -- exp >> (fn (mk, t) => mk t) ||

       scan_line "int-num" num >> HOLogic.mk_number @{typ int} ||

       binexp "<" (binop @{term "op < :: int => _"}) ||

       binexp "<=" (binop @{term "op <= :: int => _"}) ||

       binexp ">" (binop @{term "op < :: int => _"} o swap) ||

       binexp ">=" (binop @{term "op <= :: int => _"} o swap) ||

       binexp "+" (binop @{term "op + :: int => _"}) ||

       binexp "-" (binop @{term "op - :: int => _"}) ||

       binexp "*" (binop @{term "op * :: int => _"}) ||

       binexp "/" (binop @{term boogie_div}) ||

       binexp "%" (binop @{term boogie_mod}) ||

       scan_line "select" num :|-- (fn arity =>

         exp -- (scan_count exp (arity - 1) >> HOLogic.mk_tuple) >> (op $)) ||

       scan_line "store" num :|-- (fn arity =>

         exp -- (scan_count exp (arity - 2) >> HOLogic.mk_tuple) -- exp >> 

           mk_store) ||

       scan_line "bv-num" (num -- num) >> (fn (size, i) =>

         HOLogic.mk_number (mk_wordT size) i) ||

       scan_line "bv-extract" (num -- num) -- exp >> mk_extract ||

       binexp "bv-concat" mk_concat ||

       scan_fail "illegal expression") st

   in exp >> (rename_variables o unique_labels) end

 and attribute offset tds fds =

   let

     val attr_val = 

       scan_line' "expr-attr" |-- expr offset tds fds >> TermValue ||

       scan_line "string-attr" (Scan.repeat1 str) >>

         (StringValue o space_implode " ") ||

       scan_fail "illegal attribute value"

   in

     scan_line "attribute" (str -- num) :|-- (fn (name, i) =>

       scan_count attr_val i >> pair name) ||

     scan_fail "illegal attribute"

   end

 end

 fun type_decls verbose = Scan.depend (fn thy => 

   Scan.repeat (scan_line "type-decl" (str -- num -- num) :|-- (fn (ty, i) =>

     scan_count (attribute 0 Symtab.empty Symtab.empty) i >> K ty)) >>

     (fn tys => declare_types verbose tys thy))

 fun fun_decls verbose tds = Scan.depend (fn thy =>

   Scan.repeat (scan_line "fun-decl" (str -- num -- num) :|--

     (fn ((name, arity), i) =>

       scan_count (typ tds) (arity - 1) -- typ tds --

       scan_count (attribute 0 tds Symtab.empty) i >> pair name)) >>

     (fn fns => declare_functions verbose fns thy))

 fun axioms verbose tds fds unique_axs = Scan.depend (fn thy =>

   Scan.repeat (scan_line "axiom" num :|-- (fn i =>

     expr 0 tds fds --| scan_count (attribute 0 tds fds) i)) >>

     (fn axs => (add_axioms verbose (unique_axs @ axs) thy, ())))

 fun var_decls tds fds = Scan.depend (fn thy =>

   Scan.repeat (scan_line "var-decl" (str -- num) :|-- (fn (_, i) =>

     typ tds -- scan_count (attribute 0 tds fds) i >> K ())) >> K (thy, ()))

 fun local_vc_offset offsets vc_name =

    Integer.add ~1 (the_default 1 (AList.lookup (op =) offsets vc_name))

 fun vcs verbose offsets tds fds = Scan.depend (fn thy =>

   Scan.repeat (scan_line "vc" (str -- num) :-- (fn (name, _) =>

     (expr (local_vc_offset offsets name) tds fds))) >> 

     (fn vcs => ((), add_vcs verbose vcs thy)))

 fun parse verbose offsets thy = Scan.pass thy

  (type_decls verbose :|-- (fn tds =>

   fun_decls verbose tds :|-- (fn (unique_axs, fds) =>

   axioms verbose tds fds unique_axs |--

   var_decls tds fds |--

   vcs verbose offsets tds fds)))

 fun load_b2i verbose offsets path thy = finite (parse verbose offsets thy) path

 end