(** ** Big-step semantics for terminating statements and functions *)

(** The execution of a statement produces an ``outcome'', indicating
  how the execution terminated: either normally or prematurely
  through the execution of a [break], [continue] or [return] statement. *)

Inductive outcome: Type :=
   | Out_break: outcome                 (**r terminated by [break] *)
   | Out_continue: outcome              (**r terminated by [continue] *)
   | Out_normal: outcome                (**r terminated normally *)
   | Out_return: option (val * type) -> outcome.(** ** Big-step semantics for terminating statements and functions *)

(** The execution of a statement produces an ``outcome'', indicating
  how the execution terminated: either normally or prematurely
  through the execution of a [break], [continue] or [return] statement. *)

Inductive outcome: Type :=
   | Out_break: outcome                 (**r terminated by [break] *)
   | Out_continue: outcome              (**r terminated by [continue] *)
   | Out_normal: outcome                (**r terminated normally *)
   | Out_return: option (val * type) -> outcome.(** ** Big-step semantics for terminating statements and functions *)

(** The execution of a statement produces an ``outcome'', indicating
  how the execution terminated: either normally or prematurely
  through the execution of a [break], [continue] or [return] statement. *)

Inductive outcome: Type :=
   | Out_break: outcome                 (**r terminated by [break] *)
   | Out_continue: outcome              (**r terminated by [continue] *)
   | Out_normal: outcome                (**r terminated normally *)
   | Out_return: option (val * type) -> outcome.(** ** Big-step semantics for terminating statements and functions *)

(** The execution of a statement produces an ``outcome'', indicating
  how the execution terminated: either normally or prematurely
  through the execution of a [break], [continue] or [return] statement. *)

Inductive outcome: Type :=
   | Out_break: outcome                 (**r terminated by [break] *)
   | Out_continue: outcome              (**r terminated by [continue] *)
   | Out_normal: outcome                (**r terminated normally *)
   | Out_return: option (val * type) -> outcome.(** ** Big-step semantics for terminating statements and functions *)

(** The execution of a statement produces an ``outcome'', indicating
  how the execution terminated: either normally or prematurely
  through the execution of a [break], [continue] or [return] statement. *)

Inductive outcome: Type :=
   | Out_break: outcome                 (**r terminated by [break] *)
   | Out_continue: outcome              (**r terminated by [continue] *)
   | Out_normal: outcome                (**r terminated normally *)
   | Out_return: option (val * type) -> outcome.(**r terminated by [return] *)

Inductive out_normal_or_continue : outcome -> Prop :=
  | Out_normal_or_continue_N: out_normal_or_continue Out_normal
  | Out_normal_or_continue_C: out_normal_or_continue Out_continue.(**r terminated by [return] *)

Inductive out_normal_or_continue : outcome -> Prop :=
  | Out_normal_or_continue_N: out_normal_or_continue Out_normal
  | Out_normal_or_continue_C: out_normal_or_continue Out_continue.(**r terminated by [return] *)

Inductive out_normal_or_continue : outcome -> Prop :=
  | Out_normal_or_continue_N: out_normal_or_continue Out_normal
  | Out_normal_or_continue_C: out_normal_or_continue Out_continue.Inductive out_break_or_return : outcome -> outcome -> Prop :=
  | Out_break_or_return_B: out_break_or_return Out_break Out_normal
  | Out_break_or_return_R: forall ov,
      out_break_or_return (Out_return ov) (Out_return ov).Inductive out_break_or_return : outcome -> outcome -> Prop :=
  | Out_break_or_return_B: out_break_or_return Out_break Out_normal
  | Out_break_or_return_R: forall ov,
      out_break_or_return (Out_return ov) (Out_return ov).Inductive out_break_or_return : outcome -> outcome -> Prop :=
  | Out_break_or_return_B: out_break_or_return Out_break Out_normal
  | Out_break_or_return_R: forall ov,
      out_break_or_return (Out_return ov) (Out_return ov).Definition outcome_switch (out: outcome) : outcome :=
  match out with
  | Out_break => Out_normal
  | o => o
  end.Definition outcome_result_value (out: outcome) (t: type) (v: val) (m: mem): Prop :=
  match out, t with
  | Out_normal, Tvoid => v = Vundef
  | Out_return None, Tvoid => v = Vundef
  | Out_return (Some (v',t')), ty => ty <> Tvoid /\ sem_cast v' t' t m = Some v
  | _, _ => False
  end.Scheme exec_stmt_ind2 := Minimality for exec_stmt Sort Prop
  with eval_funcall_ind2 := Minimality for eval_funcall Sort Prop.Combined Scheme exec_stmt_funcall_ind from exec_stmt_ind2, eval_funcall_ind2.(** Big-step execution of a whole program.  *)

Inductive bigstep_program_terminates (p: program): trace -> int -> Prop :=
  | bigstep_program_terminates_intro: forall b f m0 m1 t r,
      let ge := globalenv p in
      Genv.init_mem p = Some m0 ->
      Genv.find_symbol ge p.(prog_main) = Some b ->
      Genv.find_funct_ptr ge b = Some f ->
      type_of_fundef f = Tfunction Tnil type_int32s cc_default ->
      eval_funcall ge m0 f nil t m1 (Vint r) ->
      bigstep_program_terminates p t r.(** Big-step execution of a whole program.  *)

Inductive bigstep_program_terminates (p: program): trace -> int -> Prop :=
  | bigstep_program_terminates_intro: forall b f m0 m1 t r,
      let ge := globalenv p in
      Genv.init_mem p = Some m0 ->
      Genv.find_symbol ge p.(prog_main) = Some b ->
      Genv.find_funct_ptr ge b = Some f ->
      type_of_fundef f = Tfunction Tnil type_int32s cc_default ->
      eval_funcall ge m0 f nil t m1 (Vint r) ->
      bigstep_program_terminates p t r.Inductive bigstep_program_diverges (p: program): traceinf -> Prop :=
  | bigstep_program_diverges_intro: forall b f m0 t,
      let ge := globalenv p in
      Genv.init_mem p = Some m0 ->
      Genv.find_symbol ge p.(prog_main) = Some b ->
      Genv.find_funct_ptr ge b = Some f ->
      type_of_fundef f = Tfunction Tnil type_int32s cc_default ->
      evalinf_funcall ge m0 f nil t ->
      bigstep_program_diverges p t.Inductive bigstep_program_diverges (p: program): traceinf -> Prop :=
  | bigstep_program_diverges_intro: forall b f m0 t,
      let ge := globalenv p in
      Genv.init_mem p = Some m0 ->
      Genv.find_symbol ge p.(prog_main) = Some b ->
      Genv.find_funct_ptr ge b = Some f ->
      type_of_fundef f = Tfunction Tnil type_int32s cc_default ->
      evalinf_funcall ge m0 f nil t ->
      bigstep_program_diverges p t.Inductive bigstep_program_diverges (p: program): traceinf -> Prop :=
  | bigstep_program_diverges_intro: forall b f m0 t,
      let ge := globalenv p in
      Genv.init_mem p = Some m0 ->
      Genv.find_symbol ge p.(prog_main) = Some b ->
      Genv.find_funct_ptr ge b = Some f ->
      type_of_fundef f = Tfunction Tnil type_int32s cc_default ->
      evalinf_funcall ge m0 f nil t ->
      bigstep_program_diverges p t.Definition bigstep_semantics (p: program) :=
  Bigstep_semantics (bigstep_program_terminates p) (bigstep_program_diverges p).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).Inductive outcome_state_match
       (e: env) (le: temp_env) (m: mem) (f: function) (k: cont): outcome -> state -> Prop :=
  | osm_normal:
      outcome_state_match e le m f k Out_normal (State f Sskip k e le m)
  | osm_break:
      outcome_state_match e le m f k Out_break (State f Sbreak k e le m)
  | osm_continue:
      outcome_state_match e le m f k Out_continue (State f Scontinue k e le m)
  | osm_return_none: forall k',
      call_cont k' = call_cont k ->
      outcome_state_match e le m f k
        (Out_return None) (State f (Sreturn None) k' e le m)
  | osm_return_some: forall a v k',
      call_cont k' = call_cont k ->
      eval_expr ge e le m a v ->
      outcome_state_match e le m f k
        (Out_return (Some (v,typeof a))) (State f (Sreturn (Some a)) k' e le m).

(* Specifications: *)
Lemma is_call_cont_call_cont: forall k, is_call_cont k -> call_cont k = k.
Lemma exec_stmt_eval_funcall_steps: (forall e le m s t le' m' out, exec_stmt ge e le m s t le' m' out -> forall f k, exists S, star step1 ge (State f s k e le m) t S /\ outcome_state_match e le' m' f k out S) /\ (forall m fd args t m' res, eval_funcall ge m fd args t m' res -> forall k, is_call_cont k -> star step1 ge (Callstate fd args k m) t (Returnstate res k m')).
Lemma exec_stmt_steps: forall e le m s t le' m' out, exec_stmt ge e le m s t le' m' out -> forall f k, exists S, star step1 ge (State f s k e le m) t S /\ outcome_state_match e le' m' f k out S.
Lemma eval_funcall_steps: forall m fd args t m' res, eval_funcall ge m fd args t m' res -> forall k, is_call_cont k -> star step1 ge (Callstate fd args k m) t (Returnstate res k m').