(* Title: HOL/SMT_Examples/boogie.ML
Author: Sascha Boehme, TU Muenchen
Proving Boogie-generated verification conditions.
*)
signature BOOGIE =
sig
val boogie_prove: theory -> string -> unit
end
structure Boogie: BOOGIE =
struct
(* utility functions *)
val as_int = fst o read_int o raw_explode
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
(* context *)
type context =
typ Symtab.table * (term * bool) Symtab.table * term list * term list
val empty_context: context = (Symtab.empty, Symtab.empty, [], [])
fun add_type name (tds, fds, axs, vcs) =
let
val T = TFree (isabelle_name name, @{sort type})
val tds' = Symtab.update (name, T) tds
in (tds', fds, axs, vcs) end
fun add_func name Ts T unique (tds, fds, axs, vcs) =
let
val t = Free (isabelle_name name, Ts ---> T)
val fds' = Symtab.update (name, (t, unique)) fds
in (tds, fds', axs, vcs) end
fun add_axiom t (tds, fds, axs, vcs) = (tds, fds, t :: axs, vcs)
fun add_vc t (tds, fds, axs, vcs) = (tds, fds, axs, t :: vcs)
fun lookup_type (tds, _, _, _) name =
(case Symtab.lookup tds name of
SOME T => T
| NONE => error "Undeclared type")
fun lookup_func (_, fds, _, _) name =
(case Symtab.lookup fds name of
SOME t_unique => t_unique
| NONE => error "Undeclared function")
(* constructors *)
fun mk_var name T = Free ("V_" ^ isabelle_name name, T)
fun mk_arrayT (Ts, T) = Type (@{type_name "fun"}, [HOLogic.mk_tupleT Ts, T])
fun mk_binary t (t1, t2) = t $ t1 $ t2
fun mk_nary _ t [] = t
| mk_nary f _ ts = uncurry (fold_rev f) (split_last ts)
fun mk_distinct [] = @{const HOL.True}
| mk_distinct [_] = @{const HOL.True}
| mk_distinct (t :: ts) =
let
fun mk_noteq u u' =
HOLogic.mk_conj (HOLogic.mk_not (HOLogic.mk_eq (t, u)), u')
in fold_rev mk_noteq ts (mk_distinct ts) end
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_quant q (Free (x, T)) t = q T $ absfree (x, T) t
| mk_quant _ t _ = raise TERM ("bad variable", [t])
fun mk_list T = HOLogic.mk_list T
val patternT = @{typ "SMT.pattern"}
fun mk_pat t =
Const (@{const_name "SMT.pat"}, Term.fastype_of t --> patternT) $ t
fun mk_pattern [] = raise TERM ("mk_pattern", [])
| mk_pattern ts = mk_list patternT (map mk_pat ts)
fun mk_trigger [] t = t
| mk_trigger pss t =
@{term "SMT.trigger"} $
mk_list @{typ "SMT.pattern list"} (map mk_pattern pss) $ t
(* parser *)
fun repeat f n ls =
let fun apply (xs, ls) = f ls |>> (fn x => x :: xs)
in funpow (as_int n) apply ([], ls) |>> rev end
fun parse_type _ (["bool"] :: ls) = (@{typ bool}, ls)
| parse_type _ (["int"] :: ls) = (@{typ int}, ls)
| parse_type cx (["array", arity] :: ls) =
repeat (parse_type cx) arity ls |>> mk_arrayT o split_last
| parse_type cx (("type-con" :: name :: _) :: ls) = (lookup_type cx name, ls)
| parse_type _ _ = error "Bad type"
fun parse_expr _ (["true"] :: ls) = (@{term True}, ls)
| parse_expr _ (["false"] :: ls) = (@{term False}, ls)
| parse_expr cx (["not"] :: ls) = parse_expr cx ls |>> HOLogic.mk_not
| parse_expr cx (["and", n] :: ls) =
parse_nary_expr cx n HOLogic.mk_conj @{term True} ls
| parse_expr cx (["or", n] :: ls) =
parse_nary_expr cx n HOLogic.mk_disj @{term False} ls
| parse_expr cx (["implies"] :: ls) =
parse_bin_expr cx (mk_binary @{term HOL.implies}) ls
| parse_expr cx (["="] :: ls) = parse_bin_expr cx HOLogic.mk_eq ls
| parse_expr cx (["var", name] :: ls) = parse_type cx ls |>> mk_var name
| parse_expr cx (["fun", name, n] :: ls) =
let val (t, _) = lookup_func cx name
in repeat (parse_expr cx) n ls |>> curry Term.list_comb t end
| parse_expr cx (("label" :: _) :: ls) = parse_expr cx ls
| parse_expr _ (["int-num", n] :: ls) =
(HOLogic.mk_number @{typ int} (as_int n), ls)
| parse_expr cx (["<"] :: ls) =
parse_bin_expr cx (mk_binary @{term "op < :: int => _"}) ls
| parse_expr cx (["<="] :: ls) =
parse_bin_expr cx (mk_binary @{term "op <= :: int => _"}) ls
| parse_expr cx ([">"] :: ls) =
parse_bin_expr cx (mk_binary @{term "op < :: int => _"}o swap) ls
| parse_expr cx ([">="] :: ls) =
parse_bin_expr cx (mk_binary @{term "op <= :: int => _"} o swap) ls
| parse_expr cx (["+"] :: ls) =
parse_bin_expr cx (mk_binary @{term "op + :: int => _"}) ls
| parse_expr cx (["-"] :: ls) =
parse_bin_expr cx (mk_binary @{term "op - :: int => _"}) ls
| parse_expr cx (["*"] :: ls) =
parse_bin_expr cx (mk_binary @{term "op * :: int => _"}) ls
| parse_expr cx (["/"] :: ls) =
parse_bin_expr cx (mk_binary @{term boogie_div}) ls
| parse_expr cx (["%"] :: ls) =
parse_bin_expr cx (mk_binary @{term boogie_mod}) ls
| parse_expr cx (["select", n] :: ls) =
repeat (parse_expr cx) n ls
|>> (fn ts => hd ts $ HOLogic.mk_tuple (tl ts))
| parse_expr cx (["store", n] :: ls) =
repeat (parse_expr cx) n ls
|>> split_last
|>> (fn (ts, t) => mk_store (hd ts) (HOLogic.mk_tuple (tl ts)) t)
| parse_expr cx (["forall", vars, pats, atts] :: ls) =
parse_quant cx HOLogic.all_const vars pats atts ls
| parse_expr cx (["exists", vars, pats, atts] :: ls) =
parse_quant cx HOLogic.exists_const vars pats atts ls
| parse_expr _ _ = error "Bad expression"
and parse_bin_expr cx f ls = ls |> parse_expr cx ||>> parse_expr cx |>> f
and parse_nary_expr cx n f c ls =
repeat (parse_expr cx) n ls |>> mk_nary (curry f) c
and parse_quant cx q vars pats atts ls =
let
val ((((vs, pss), _), t), ls') =
ls
|> repeat (parse_var cx) vars
||>> repeat (parse_pat cx) pats
||>> repeat (parse_attr cx) atts
||>> parse_expr cx
in (fold_rev (mk_quant q) vs (mk_trigger pss t), ls') end
and parse_var cx (["var", name] :: ls) = parse_type cx ls |>> mk_var name
| parse_var _ _ = error "Bad variable"
and parse_pat cx (["pat", n] :: ls) = repeat (parse_expr cx) n ls
| parse_pat _ _ = error "Bad pattern"
and parse_attr cx (["attribute", name, n] :: ls) =
let
fun attr (["expr-attr"] :: ls) = parse_expr cx ls |>> K ()
| attr (("string-attr" :: _) :: ls) = ((), ls)
| attr _ = error "Bad attribute value"
in repeat attr n ls |>> K name end
| parse_attr _ _ = error "Bad attribute"
fun parse_func cx arity n ls =
let
val ((Ts, atts), ls') =
ls |> repeat (parse_type cx) arity ||>> repeat (parse_attr cx) n
val unique = member (op =) atts "unique"
in ((split_last Ts, unique), ls') end
fun parse_decl (("type-decl" :: name :: _) :: ls) cx = (ls, add_type name cx)
| parse_decl (["fun-decl", name, arity, n] :: ls) cx =
let val (((Ts, T), unique), ls') = parse_func cx arity n ls
in (ls', add_func name Ts T unique cx) end
| parse_decl (("axiom" :: _) :: ls) cx =
let val (t, ls') = parse_expr cx ls
in (ls', add_axiom t cx) end
| parse_decl (("var-decl" :: _) :: ls) cx =
parse_type cx ls |> snd |> rpair cx
| parse_decl (("vc" :: _) :: ls) cx =
let val (t, ls') = parse_expr cx ls
in (ls', add_vc t cx) end
| parse_decl _ _ = error "Bad declaration"
fun parse_lines [] cx = cx
| parse_lines ls cx = parse_decl ls cx |-> parse_lines
(* splitting of text into a lists of lists of tokens *)
fun is_blank c = (c = " " orelse c = "\t" orelse c = "\r" orelse c = "\n")
fun explode_lines text =
text
|> split_lines
|> map (String.tokens (is_blank o str))
|> filter (fn [] => false | _ => true)
(* proving verification conditions *)
fun add_unique_axioms (tds, fds, axs, vcs) =
Symtab.fold (fn (_, (t, true)) => cons t | _ => I) fds []
|> map (swap o Term.dest_Free)
|> AList.group (op =)
|> map (fn (T, ns) => mk_distinct (map (Free o rpair T) ns))
|> (fn axs' => (tds, fds, axs' @ axs, vcs))
fun build_proof_context thy (tds, fds, axs, vcs) =
let
val vc =
(case vcs of
[vc] => vc
| _ => error "Bad number of verification conditions")
in
Proof_Context.init_global thy
|> Symtab.fold (fn (_, T) => Variable.declare_typ T) tds
|> Symtab.fold (fn (_, (t, _)) => Variable.declare_term t) fds
|> fold Variable.declare_term axs
|> fold Variable.declare_term vcs
|> pair (map HOLogic.mk_Trueprop axs, HOLogic.mk_Trueprop vc)
end
val boogie_rules =
[@{thm fst_conv}, @{thm snd_conv}, @{thm pair_collapse}] @
[@{thm fun_upd_same}, @{thm fun_upd_apply}]
fun boogie_tac ctxt axioms =
ALLGOALS (SMT_Solver.smt_tac ctxt (boogie_rules @ axioms))
fun boogie_prove thy text =
let
val lines = explode_lines text
val ((axioms, vc), ctxt) =
empty_context
|> parse_lines lines
|> add_unique_axioms
|> build_proof_context thy
val _ = Goal.prove ctxt [] axioms vc (fn {prems, context} =>
boogie_tac context prems)
val _ = writeln "Verification condition proved successfully"
in () end
(* Isar command *)
val _ =
Outer_Syntax.command @{command_spec "boogie_file"}
"prove verification condition from .b2i file"
(Thy_Load.provide_parse_files "boogie_file" >> (fn files =>
Toplevel.theory (fn thy =>
let
val ([{text, ...}], thy') = files thy;
val _ = boogie_prove thy' text;
in thy' end)))
end