diff --git a/src/HOL/Tools/SMT/smt_solver.ML b/src/HOL/Tools/SMT/smt_solver.ML
--- a/src/HOL/Tools/SMT/smt_solver.ML
+++ b/src/HOL/Tools/SMT/smt_solver.ML
@@ -1,316 +1,316 @@
 (*  Title:      HOL/Tools/SMT/smt_solver.ML
     Author:     Sascha Boehme, TU Muenchen
 
 SMT solvers registry and SMT tactic.
 *)
 
 signature SMT_SOLVER =
 sig
   (*configuration*)
   datatype outcome = Unsat | Sat | Unknown | Time_Out
 
   type parsed_proof =
     {outcome: SMT_Failure.failure option,
      fact_ids: (int * ((string * ATP_Problem_Generate.stature) * thm)) list option,
      atp_proof: unit -> (term, string) ATP_Proof.atp_step list}
 
   type solver_config =
     {name: string,
      class: Proof.context -> SMT_Util.class,
      avail: unit -> bool,
      command: unit -> string list,
      options: Proof.context -> string list,
      smt_options: (string * string) list,
      default_max_relevant: int,
      outcome: string -> string list -> outcome * string list,
      parse_proof: (Proof.context -> SMT_Translate.replay_data ->
        ((string * ATP_Problem_Generate.stature) * thm) list -> term list -> term -> string list ->
        parsed_proof) option,
      replay: (Proof.context -> SMT_Translate.replay_data -> string list -> thm) option}
 
   (*registry*)
   val add_solver: solver_config -> theory -> theory
   val default_max_relevant: Proof.context -> string -> int
 
   (*filter*)
   val smt_filter: Proof.context -> thm -> ((string * ATP_Problem_Generate.stature) * thm) list ->
     int -> Time.time -> parsed_proof
 
   (*tactic*)
   val smt_tac: Proof.context -> thm list -> int -> tactic
   val smt_tac': Proof.context -> thm list -> int -> tactic
 end;
 
 structure SMT_Solver: SMT_SOLVER =
 struct
 
 (* interface to external solvers *)
 
 local
 
 fun make_command command options problem_path proof_path =
   Bash.strings (command () @ options) ^ " " ^
     File.bash_platform_path problem_path ^
     " > " ^ File.bash_path proof_path ^ " 2>&1"
 
 fun with_trace ctxt msg f x =
   let val _ = SMT_Config.trace_msg ctxt (fn () => msg) ()
   in f x end
 
 fun run ctxt name mk_cmd input =
   (case SMT_Config.certificates_of ctxt of
     NONE =>
       if not (SMT_Config.is_available ctxt name) then
         error ("The SMT solver " ^ quote name ^ " is not installed")
       else if Config.get ctxt SMT_Config.debug_files = "" then
         with_trace ctxt ("Invoking SMT solver " ^ quote name ^ " ...") (Cache_IO.run mk_cmd) input
       else
         let
           val base_path = Path.explode (Config.get ctxt SMT_Config.debug_files)
           val in_path = Path.ext "smt_in" base_path
           val out_path = Path.ext "smt_out" base_path
         in Cache_IO.raw_run mk_cmd input in_path out_path end
   | SOME certs =>
       (case Cache_IO.lookup certs input of
         (NONE, key) =>
           if Config.get ctxt SMT_Config.read_only_certificates then
             error ("Bad certificate cache: missing certificate")
           else
             Cache_IO.run_and_cache certs key mk_cmd input
       | (SOME output, _) =>
           with_trace ctxt ("Using cached certificate from " ^
             Path.print (Cache_IO.cache_path_of certs) ^ " ...") I output))
 
 (* Z3 returns 1 if "get-proof" or "get-model" fails. veriT returns 255. *)
 val normal_return_codes = [0, 1, 255]
 
 fun run_solver ctxt name mk_cmd input =
   let
     fun pretty tag lines = Pretty.string_of (Pretty.big_list tag (map Pretty.str lines))
 
     val _ = SMT_Config.trace_msg ctxt (pretty "Problem:" o split_lines) input
 
     val ({elapsed, ...}, {redirected_output = res, output = err, return_code}) =
       Timing.timing (SMT_Config.with_timeout ctxt (run ctxt name mk_cmd)) input
     val _ = SMT_Config.trace_msg ctxt (pretty "Solver:") err
 
     val output = drop_suffix (equal "") res
     val _ = SMT_Config.trace_msg ctxt (pretty "Result:") output
-    val _ = SMT_Config.trace_msg ctxt (pretty "Time (ms):") [\<^make_string> (Time.toMilliseconds elapsed)]
-    val _ = SMT_Config.statistics_msg ctxt (pretty "Time (ms):") [\<^make_string> (Time.toMilliseconds elapsed)]
+    val _ = SMT_Config.trace_msg ctxt (pretty "Time:") [Value.print_time elapsed ^ "s"]
+    val _ = SMT_Config.statistics_msg ctxt (pretty "Time:") [Value.print_time elapsed ^ "s"]
 
     val _ = member (op =) normal_return_codes return_code orelse
       raise SMT_Failure.SMT (SMT_Failure.Abnormal_Termination return_code)
   in output end
 
 fun trace_assms ctxt =
   SMT_Config.trace_msg ctxt (Pretty.string_of o
     Pretty.big_list "Assertions:" o map (Thm.pretty_thm ctxt o snd))
 
 fun trace_replay_data ({context = ctxt, typs, terms, ...} : SMT_Translate.replay_data) =
   let
     fun pretty_eq n p = Pretty.block [Pretty.str n, Pretty.str " = ", p]
     fun p_typ (n, T) = pretty_eq n (Syntax.pretty_typ ctxt T)
     fun p_term (n, t) = pretty_eq n (Syntax.pretty_term ctxt t)
   in
     SMT_Config.trace_msg ctxt (fn () =>
       Pretty.string_of (Pretty.big_list "Names:" [
         Pretty.big_list "sorts:" (map p_typ (Symtab.dest typs)),
         Pretty.big_list "functions:" (map p_term (Symtab.dest terms))])) ()
   end
 
 in
 
 fun invoke name command smt_options ithms ctxt =
   let
     val options = SMT_Config.solver_options_of ctxt
     val comments = [space_implode " " options]
 
     val (str, replay_data as {context = ctxt', ...}) =
       ithms
       |> tap (trace_assms ctxt)
       |> SMT_Translate.translate ctxt smt_options comments
       ||> tap trace_replay_data
   in (run_solver ctxt' name (make_command command options) str, replay_data) end
 
 end
 
 
 (* configuration *)
 
 datatype outcome = Unsat | Sat | Unknown | Time_Out
 
 type parsed_proof =
   {outcome: SMT_Failure.failure option,
    fact_ids: (int * ((string * ATP_Problem_Generate.stature) * thm)) list option,
    atp_proof: unit -> (term, string) ATP_Proof.atp_step list}
 
 type solver_config =
   {name: string,
    class: Proof.context -> SMT_Util.class,
    avail: unit -> bool,
    command: unit -> string list,
    options: Proof.context -> string list,
    smt_options: (string * string) list,
    default_max_relevant: int,
    outcome: string -> string list -> outcome * string list,
    parse_proof: (Proof.context -> SMT_Translate.replay_data ->
      ((string * ATP_Problem_Generate.stature) * thm) list -> term list -> term -> string list ->
      parsed_proof) option,
    replay: (Proof.context -> SMT_Translate.replay_data -> string list -> thm) option}
 
 
 (* check well-sortedness *)
 
 val has_topsort = Term.exists_type (Term.exists_subtype (fn
     TFree (_, []) => true
   | TVar (_, []) => true
   | _ => false))
 
 (* top sorts cause problems with atomization *)
 fun check_topsort ctxt thm =
   if has_topsort (Thm.prop_of thm) then (SMT_Normalize.drop_fact_warning ctxt thm; TrueI) else thm
 
 
 (* registry *)
 
 type solver_info = {
   command: unit -> string list,
   smt_options: (string * string) list,
   default_max_relevant: int,
   parse_proof: Proof.context -> SMT_Translate.replay_data ->
     ((string * ATP_Problem_Generate.stature) * thm) list -> term list -> term -> string list ->
     parsed_proof,
   replay: Proof.context -> SMT_Translate.replay_data -> string list -> thm}
 
 structure Solvers = Generic_Data
 (
   type T = solver_info Symtab.table
   val empty = Symtab.empty
   val extend = I
   fun merge data = Symtab.merge (K true) data
 )
 
 local
   fun parse_proof outcome parse_proof0 outer_ctxt replay_data xfacts prems concl output =
     (case outcome output of
       (Unsat, lines) =>
         (case parse_proof0 of
           SOME pp => pp outer_ctxt replay_data xfacts prems concl lines
         | NONE => {outcome = NONE, fact_ids = NONE, atp_proof = K []})
     | (Time_Out, _) => raise SMT_Failure.SMT (SMT_Failure.Time_Out)
     | (result, _) => raise SMT_Failure.SMT (SMT_Failure.Counterexample (result = Sat)))
 
   fun replay outcome replay0 oracle outer_ctxt
       (replay_data as {context = ctxt, ...} : SMT_Translate.replay_data) output =
     (case outcome output of
       (Unsat, lines) =>
         if Config.get ctxt SMT_Config.oracle then
           oracle ()
         else
           (case replay0 of
             SOME replay => replay outer_ctxt replay_data lines
           | NONE => error "No proof reconstruction for solver -- \
             \declare [[smt_oracle]] to allow oracle")
     | (Time_Out, _) => raise SMT_Failure.SMT (SMT_Failure.Time_Out)
     | (result, _) => raise SMT_Failure.SMT (SMT_Failure.Counterexample (result = Sat)))
 
   val cfalse = Thm.cterm_of \<^context> \<^prop>\<open>False\<close>
 in
 
 fun add_solver ({name, class, avail, command, options, smt_options, default_max_relevant, outcome,
     parse_proof = parse_proof0, replay = replay0} : solver_config) =
   let
     fun solver oracle = {
       command = command,
       smt_options = smt_options,
       default_max_relevant = default_max_relevant,
       parse_proof = parse_proof (outcome name) parse_proof0,
       replay = replay (outcome name) replay0 oracle}
 
     val info = {name = name, class = class, avail = avail, options = options}
   in
     Thm.add_oracle (Binding.name name, K cfalse) #-> (fn (_, oracle) =>
     Context.theory_map (Solvers.map (Symtab.update_new (name, solver oracle)))) #>
     Context.theory_map (SMT_Config.add_solver info)
   end
 
 end
 
 fun get_info ctxt name = the (Symtab.lookup (Solvers.get (Context.Proof ctxt)) name)
 
 fun name_and_info_of ctxt =
   let val name = SMT_Config.solver_of ctxt
   in (name, get_info ctxt name) end
 
 val default_max_relevant = #default_max_relevant oo get_info
 
 fun apply_solver_and_replay ctxt thms0 =
   let
     val thms = map (check_topsort ctxt) thms0
     val (name, {command, smt_options, replay, ...}) = name_and_info_of ctxt
     val (output, replay_data) =
       invoke name command smt_options (SMT_Normalize.normalize ctxt thms) ctxt
   in replay ctxt replay_data output end
 
 
 (* filter (for Sledgehammer) *)
 
 fun smt_filter ctxt0 goal xfacts i time_limit =
   let
     val ctxt = ctxt0 |> Config.put SMT_Config.timeout (Time.toReal time_limit)
 
     val ({context = ctxt, prems, concl, ...}, _) = Subgoal.focus ctxt i NONE goal
     fun negate ct = Thm.dest_comb ct ||> Thm.apply \<^cterm>\<open>Not\<close> |-> Thm.apply
     val cprop =
       (case try negate (Thm.rhs_of (SMT_Normalize.atomize_conv ctxt concl)) of
         SOME ct => ct
       | NONE => raise SMT_Failure.SMT (SMT_Failure.Other_Failure "cannot atomize goal"))
 
     val conjecture = Thm.assume cprop
     val facts = map snd xfacts
     val thms = conjecture :: prems @ facts
     val thms' = map (check_topsort ctxt) thms
 
     val (name, {command, smt_options, parse_proof, ...}) = name_and_info_of ctxt
     val (output, replay_data) =
       invoke name command smt_options (SMT_Normalize.normalize ctxt thms') ctxt
   in
     parse_proof ctxt replay_data xfacts (map Thm.prop_of prems) (Thm.term_of concl) output
   end
   handle SMT_Failure.SMT fail => {outcome = SOME fail, fact_ids = NONE, atp_proof = K []}
 
 
 (* SMT tactic *)
 
 local
   fun str_of ctxt fail =
     "Solver " ^ SMT_Config.solver_of ctxt ^ ": " ^ SMT_Failure.string_of_failure fail
 
   fun safe_solve ctxt facts = SOME (apply_solver_and_replay ctxt facts)
     handle
       SMT_Failure.SMT (fail as SMT_Failure.Counterexample _) =>
         (SMT_Config.verbose_msg ctxt (str_of ctxt) fail; NONE)
     | SMT_Failure.SMT (fail as SMT_Failure.Time_Out) =>
         (SMT_Config.verbose_msg ctxt (K ("SMT: Solver " ^ quote (SMT_Config.solver_of ctxt) ^ ": " ^
           SMT_Failure.string_of_failure fail ^ " (setting the " ^
           "configuration option " ^ quote (Config.name_of SMT_Config.timeout) ^ " might help)")) ();
          NONE)
     | SMT_Failure.SMT fail => error (str_of ctxt fail)
 
   fun resolve ctxt (SOME thm) = resolve_tac ctxt [thm] 1
     | resolve _ NONE = no_tac
 
   fun tac prove ctxt rules =
     CONVERSION (SMT_Normalize.atomize_conv ctxt)
     THEN' resolve_tac ctxt @{thms ccontr}
     THEN' SUBPROOF (fn {context = ctxt', prems, ...} =>
       resolve ctxt' (prove ctxt' (rules @ prems))) ctxt
 in
 
 val smt_tac = tac safe_solve
 val smt_tac' = tac (SOME oo apply_solver_and_replay)
 
 end
 
 end;