include "joint/semanticsUtils.ma".
include "common/StructuredTraces.ma".

record evaluation_params (p : sem_params) : Type[0] ≝
{ globals : list ident
; ev_genv :> genv p globals
}.

record prog_params : Type[1] ≝
 { prog_spars :> sem_params
 ; prog : joint_program prog_spars
 ; stack_sizes : ident → option ℕ
(* ; prog_io : state prog_spars → ∀o.res (io_in o) *)
 }.

definition joint_make_global : ∀p : prog_params.evaluation_params (prog_spars p) ≝
λp.mk_evaluation_params ?
  (prog_names … (prog p))
  (joint_globalenv p (prog p) (stack_sizes p)).

coercion joint_make_global : ∀p : prog_params.evaluation_params (prog_spars p) ≝
joint_make_global on p : prog_params to evaluation_params ?.

definition make_initial_state :
 ∀pars: prog_params.res (state_pc pars) ≝
λpars.let p ≝ prog pars in
  let ge ≝ ev_genv pars in
  (* this is going to change shortly: globals will not reside in globalenv anymore *)
  ! m0 ← init_mem … (λx.x) p ;
  let 〈m,spb〉 as H ≝ alloc … m0 0 external_ram_size in
  let globals_size ≝ globals_stacksize … p in
  (* stack pointer should start at 2^16 - |globals|, right?
     first call to main shuold bring it to 2^16 - |globals| - |main stack|
     Also, on words 2^16 - |globals| = - |globals| *)
  (* mcu8051ide disallows byte FFFFh of XDATA... bug or feature? *)
  let spp : xpointer ≝
    «mk_pointer spb (mk_offset (bitvector_of_Z 16 (-S (globals_size)))),
     pi2 … spb» in
(*  let ispp : xpointer ≝ mk_pointer ispb (mk_offset (bitvector_of_nat ? 47)) in *)
  let main ≝ prog_main … p in
  let st ≝ mk_state pars
    (* frames ≝ *)(Some ? (empty_framesT …))
    (* internal_stack ≝ *) empty_is
    (* carry ≝ *)(BBbit false)
    (* regs ≝ *)(empty_regsT … spp)
    (* mem ≝ *)m
    (* stack_usage ≝ *)0 in
  return
  mk_state_pc ?
    (* state_no_pc ≝ *)(set_sp … spp st)
    (* pc ≝ *)init_pc
    (* last_pop ≝ *)(null_pc one).
@hide_prf
cases m0 in H; #m1 #m2 #m3 #H
whd in H:(???%); destruct whd in ⊢(??%?); @Zleb_elim_Type0 // #abs @⊥
@(absurd … (irreflexive_Zlt …)) % #I cases (I OZ) /3 by Zlt_to_Zle_to_Zlt/
qed.

definition joint_classify_step :
  ∀p,globals.joint_step p globals → status_class ≝
  λp,g,stmt.
  match stmt with
  [ CALL f args dest ⇒ cl_call
  | COND _ _ ⇒ cl_jump
  | _ ⇒ cl_other
  ].

definition joint_classify_final :
  ∀p.joint_fin_step p → status_class ≝
  λp,stmt.
  match stmt with
  [ GOTO _ ⇒ cl_other
  | RETURN ⇒ cl_return
  | TAILCALL _ f args ⇒ cl_tailcall
  ].

definition joint_classify :
  ∀p.∀pars : evaluation_params p.state_pc p → status_class ≝
  λp,pars,st.
  match fetch_statement … (ev_genv … pars) (pc … st) with
  [ OK i_fn_s ⇒
    match \snd i_fn_s with
    [ sequential s _ ⇒ joint_classify_step … s
    | final s ⇒ joint_classify_final … s
    | FCOND _ _ _ _ ⇒ cl_jump
    ]
  | _ ⇒ cl_other
  ].

lemma joint_classify_call : ∀p,pars,st.
  joint_classify p pars st = cl_call →
  ∃i_f,f',args,dest,next.
  fetch_statement … (ev_genv … pars) (pc … st) =
    OK ? 〈i_f, sequential … (CALL … f' args dest) next〉.
#p #pars #st
whd in match joint_classify; normalize nodelta
inversion (fetch_statement ????)
[2: #e #_ whd in ⊢ (??%?→?); #ABS destruct(ABS) ]
* #i_f *
[2,3: [ * [ #lbl | | #fl #f #args ] | #fl #a #ltrue #lfalse ] #_
  normalize nodelta normalize in ⊢ (%→?); #ABS destruct
]
* [ #c | #f' #args #dest | #a #lbl | #s ] #nxt #fetch normalize nodelta
normalize in ⊢ (%→?); #EQ destruct
%[|%[|%[|%[|%[| %]]]]]
qed.

definition joint_after_ret : ∀p : sem_params.∀pars.
  (Σs : state_pc p.joint_classify p pars s = cl_call) → state_pc p → Prop ≝
λp,pars,s1,s2.
match fetch_statement … (ev_genv … pars) (pc … s1) with
[ OK x ⇒
  match \snd x with
  [ sequential s next ⇒
    last_pop … s2 = pc … s1 ∧
    pc … s2 = succ_pc p (pc … s1) next
  | _ ⇒ False (* never happens *)
  ]
| _ ⇒ False (* never happens *)
].

definition joint_call_ident : ∀p : sem_params.∀pars.
  state_pc p → ident ≝
(* this is a definition without a dummy ident :
λp,st.
match ?
return λx.
  !〈f, s〉 ← fetch_statement ? p … (ev_genv p) (pc … st) ;
  match s with
  [ sequential s next ⇒
    match s with
    [ CALL f' args dest ⇒ function_of_call … (ev_genv p) st f'
    | _ ⇒ Error … [ ]
    ]
  | _ ⇒ Error … [ ]
  ] = x → ? with
[ OK v ⇒ λ_.v
| Error e ⇒ λABS.⊥
] (refl …).
@hide_prf
elim (joint_classify_call … (pi2 … st))
#f *#f' *#args *#dest *#next *#fn *#fd ** #EQ1 #EQ2 #EQ3
lapply ABS -ABS
>EQ1 >m_return_bind normalize nodelta >EQ2 #ABS destruct(ABS)
qed. *)
(* with a dummy ident (which is never used as seen above in the commented script)
   I think handling of the function is easier *)
λp,pars,st.
let dummy : ident ≝ an_identifier ? one in (* used where it cannot ever happen *)
match fetch_statement … (ev_genv … pars) (pc … st) with
[ OK x ⇒
  match \snd x with
  [ sequential s next ⇒
    match s with
    [ CALL f' args dest ⇒
      match
        (! bl ← block_of_call … (ev_genv … pars) f' st;
         fetch_internal_function … (ev_genv … pars) bl) with
      [ OK i_f ⇒ \fst i_f
      | _ ⇒ dummy
      ]
    | _ ⇒ dummy
    ]
  | _ ⇒ dummy
  ]
| _ ⇒ dummy
].

definition joint_tailcall_ident : ∀p:sem_params.∀pars.
  state_pc p → ident ≝
λp,pars,st.
let dummy : ident ≝ an_identifier ? one in (* used where it cannot ever happen *)
match fetch_statement … (ev_genv … pars) (pc … st) with
[ OK x ⇒
  match \snd x with
  [ final s ⇒
    match s with
    [ TAILCALL _ f' args ⇒
      match
        (! bl ← block_of_call … (ev_genv … pars) f' st;
         fetch_internal_function … (ev_genv … pars) bl) with
      [ OK i_f ⇒ \fst i_f
      | _ ⇒ dummy
      ]
    | _ ⇒ dummy
    ]
  | _ ⇒ dummy
  ]
| _ ⇒ dummy
].

definition pcDeq ≝ mk_DeqSet program_counter eq_program_counter ?.
*#p1 #EQ1 * #p2 #EQ2 @eq_program_counter_elim
[ #EQ destruct % #H %
| * #NEQ % #ABS destruct elim (NEQ ?) %
]
qed.

(*
let rec io_evaluate O I X (env : ∀o.res (I o)) (c : IO O I X) on c : res X ≝
  match c with
  [ Value x ⇒ OK … x
  | Interact o f ⇒
    ! i ← env o ;
    io_evaluate O I X env (f i)
  | Wrong e ⇒ Error … e
  ].
*)

definition cost_label_of_stmt :
  ∀p,globals.joint_statement p globals → option costlabel ≝
  λp,g,s.match s with
  [ sequential s _ ⇒
    match s with
    [  COST_LABEL lbl ⇒ Some ? lbl
    | _ ⇒ None ?
    ]
  | _ ⇒ None ?
  ].

definition joint_label_of_pc ≝
  λp,pars.
    (λpc.
      match fetch_statement … (ev_genv p pars) pc with
      [ OK fn_stmt ⇒ cost_label_of_stmt … (\snd fn_stmt)
      | _ ⇒ None ?
      ]).

(* the prime is to render obsolete old definition of exit_pc, remove when all is corrected *)
definition exit_pc' : program_counter ≝
mk_program_counter «mk_block (-1), refl …» (p1 one).

definition joint_final: ∀p: sem_params.∀pars.
  state_pc p → option int ≝
 λp,pars,st.
 let ge ≝ ev_genv p pars in
 if eq_program_counter (pc … st) exit_pc' then
   let ret ≝ call_dest_for_main ?? p in
   match (! vals ← read_result … ge ret st ;
               Word_of_list_beval vals)
   with
   [ OK v ⇒ Some ? v
   | Error _ ⇒ Some … (maximum ?) ]
 else None ?.

definition joint_abstract_status :
 ∀p : prog_params.
 abstract_status ≝
 λp.
 mk_abstract_status
   (* as_status ≝ *) (state_pc p)
   (* as_execute ≝ *)
    (λs1,s2.eval_state … (ev_genv … p) s1 = return s2)
   (* (* as_init ≝ *) (make_initial_state p) *)
   (* as_pc ≝ *) pcDeq
   (* as_pc_of ≝ *) (pc …)
   (* as_classify ≝ *) (joint_classify … p)
   (* as_label_of_pc ≝ *) (joint_label_of_pc … p)
   (* as_after_return ≝ *) (joint_after_ret … p)
   (* as_result ≝ *) (joint_final … p)
   (* as_call_ident ≝ *) (λst.joint_call_ident … p st)
   (* as_tailcall_ident ≝ *) (λst.joint_tailcall_ident … p st).

(* alternative definition with integrated prog_params constructor *)
definition joint_status :
 ∀p : sem_params.
 joint_program p → (ident → option ℕ) → abstract_status ≝
λp,prog,stacksizes.joint_abstract_status (mk_prog_params p prog stacksizes).