source: src/RTLabs/import.ma @ 1054

include "RTLabs/semantics.ma".

let rec n_idents (n:nat) (tag:String) (g:universe tag) : res (Vector (identifier tag) n × (universe tag)) ≝
match n with
[ O ⇒ OK ? 〈[[ ]], g〉
| S m ⇒ do 〈ls, g'〉 ← n_idents m tag g;
        do 〈l, g''〉 ← fresh ? g';
        OK ? 〈l:::ls, g''〉
].

definition pre_register ≝ nat.

record pre_internal_function : Type[0] ≝
{ pf_result    : option (pre_register × typ)
; pf_params    : list (pre_register × typ)
; pf_locals    : list (pre_register × typ)
; pf_stacksize : nat
; pf_graph     : list (nat × ((pre_register → res register) → (nat → res label) → res statement))
; pf_entry     : nat
; pf_exit      : nat
}.

definition make_register : 
  (pre_register → option register) → pre_register → universe RegisterTag →
  res ((nat → option register) × (universe RegisterTag) × register) ≝
λm,reg,g.
  match m reg with
  [ Some r' ⇒ OK ? 〈〈m,g〉,r'〉
  | None ⇒ do 〈r',g'〉 ← fresh ? g;
           OK ? 〈〈λn. if eqb reg n then Some ? r' else m n,g'〉,r'〉
  ]
.

definition make_registers_list :
  (nat → option register) → list (pre_register × typ) → universe RegisterTag →
  res ((nat → option register) × (universe RegisterTag) × (list (register×typ))) ≝
λm,lrs,g.
foldr ?? (λrst,acc. do 〈acc',l〉 ← acc;
                   let 〈rs,ty〉 ≝ rst in
                   let 〈m,g〉 ≝ acc' in 
                   do 〈mg,rs'〉 ← make_register m rs g;
                   OK ? 〈mg,〈rs',ty〉::l〉) (OK ? 〈〈m,g〉,[ ]〉) lrs.

axiom MissingRegister : String.
axiom MissingLabel : String.

definition make_internal_function : pre_internal_function → res (fundef internal_function) ≝
λpre_f.
  let rgen0 ≝ new_universe RegisterTag in
  do 〈rmapgen1, result〉 ← match pf_result pre_f with
                          [ None ⇒ OK ? 〈〈λ_.None ?, rgen0〉, None ?〉
                          | Some rt ⇒ do 〈x,y〉 ← make_register (λ_.None ?) (\fst rt) rgen0; OK ? 〈x,Some ? 〈y,\snd rt〉〉
                          ];
  let 〈rmap1, rgen1〉 ≝ rmapgen1 in
  do 〈rmapgen2, params〉 ← make_registers_list rmap1 (pf_params pre_f) rgen1;
  let 〈rmap2, rgen2〉 ≝ rmapgen2 in
  do 〈rmapgen3, locals〉 ← make_registers_list rmap2 (pf_locals pre_f) rgen2;
  let 〈rmap3, rgen3〉 ≝ rmapgen3 in
  let rmap ≝ λn. opt_to_res … (msg MissingRegister) (rmap3 n) in
  let max_stmt ≝ foldr ?? (λp,m. max (\fst p) m) 0 (pf_graph pre_f) in
  do 〈labels, gen〉 ← n_idents (S max_stmt) ? (new_universe LabelTag);
  let get_label ≝ λn. opt_to_res … (msg MissingLabel) (get_index_weak_v ?? labels n) in
  do graph ← foldr ?? (λp:nat × ((pre_register → res register) → (nat → res label) → res statement).λg0.
                         do g ← g0;
                         let 〈l,s〉 ≝ p in
                         do l' ← get_label l;
                         do s' ← s rmap get_label;
                         OK ? (add ?? g l' s')) (OK ? (empty_map ??)) (pf_graph pre_f);
  do entry ← get_label (pf_entry pre_f);
  do exit ← get_label (pf_exit pre_f);
  OK ? (Internal ? (mk_internal_function
         gen
         rgen3
         result
         params
         locals
         (pf_stacksize pre_f)
         graph
         entry
         exit
         )).

definition make_reg_list : (nat → res register) → list pre_register → res (list register) ≝
λm,ps. foldr ?? (λp,rs0. do rs ← rs0; do r ← m p; OK ? (r::rs)) (OK ? [ ]) ps.

(* XXX move somewhere sensible *)
let rec mmap_vec (A:Type[0]) (B:Type[0]) (f:A → res B) (n:nat) (v:Vector A n) on v : res (Vector B n) ≝
match v with
[ VEmpty ⇒ OK ? (VEmpty …)
| VCons m hd tl ⇒ do hd' ← f hd;
                  do tl' ← mmap_vec A B f m tl;
                  OK ? (hd':::tl')
].

definition make_opt_reg : (pre_register → res register) → option pre_register → res (option register) ≝
λm,o. match o with [ None ⇒ OK ? (None ?) | Some r ⇒ do r' ← m r; OK ? (Some ? r') ].

let rec make_St_skip l ≝ λr:nat → res register.λf:nat → res label. do l' ← f l; OK ? (St_skip l').
let rec make_St_cost cl l ≝ λr:nat → res register.λf:nat → res label. do l' ← f l; OK ? (St_cost cl l').
let rec make_St_const rs cst l ≝ λr:nat → res register.λf:nat → res label. do rs' ← r rs; do l' ← f l; OK ? (St_const rs' cst l').
let rec make_St_op1 op dst src l ≝ λr:nat → res register.λf:nat → res label. do dst' ← r dst; do src' ← r src; do l' ← f l; OK ? (St_op1 op dst' src' l').
let rec make_St_op2 op dst src1 src2 l ≝ λr:nat → res register.λf:nat → res label. do dst' ← r dst; do src1' ← r src1; do src2' ← r src2; do l' ← f l; OK ? (St_op2 op dst' src1' src2' l').
let rec make_St_load chunk addr dst l ≝ λr:nat → res register.λf:nat → res label. do addr' ← r addr; do dst' ← r dst; do l' ← f l; OK ? (St_load chunk addr' dst' l').
let rec make_St_store chunk addr src l ≝ λr:nat → res register.λf:nat → res label. do addr' ← r addr; do src' ← r src; do l' ← f l; OK ? (St_store chunk addr' src' l').
let rec make_St_call_id id args dst l ≝ λr:nat → res register.λf:nat → res label. do args' ← make_reg_list r args; do dst' ← make_opt_reg r dst; do l' ← f l; OK ? (St_call_id id args' dst' l').
let rec make_St_call_ptr frs args dst l ≝ λr:nat → res register.λf:nat → res label. do frs' ← r frs; do args' ← make_reg_list r args; do dst' ← make_opt_reg r dst; do l' ← f l; OK ? (St_call_ptr frs' args' dst' l').
let rec make_St_tailcall_id id args ≝ λr:nat → res register.λf:nat → res label.  do args' ← make_reg_list r args; OK statement (St_tailcall_id id args').
let rec make_St_tailcall_ptr frs args ≝ λr:nat → res register.λf:nat → res label. do frs' ← r frs; do args' ← make_reg_list r args; OK statement (St_tailcall_ptr frs' args').
let rec make_St_cond src ltrue lfalse ≝ λr:nat → res register.λf:nat → res label. do src' ← r src; do ltrue' ← f ltrue; do lfalse' ← f lfalse;  OK ? (St_cond src' ltrue' lfalse').
let rec make_St_jumptable rs ls ≝ λr:nat → res register.λf:nat → res label. do rs' ← r rs; do ls' ← foldr ?? (λl,ls0. do ls ← ls0; do l' ← f l; OK ? (l'::ls)) (OK ? [ ]) ls; OK ? (St_jumptable rs' ls').
definition make_St_return ≝ λr:nat → res register.λf:nat → res label. OK statement St_return.