source: src/Clight/toCminor.ma @ 2465

Last change on this file since 2465 was 2465, checked in by campbell, 7 years ago

Remove obsolete comment (runtime functions should be implemented later in
the compiler).

File size: 74.7 KB
Line 
1include "Clight/ClassifyOp.ma".
2include "basics/lists/list.ma".
3include "Clight/fresh.ma".
4
5(* Identify local variables that must be allocated memory. *)
6(* These are the variables whose addresses are taken. *)
7let rec gather_mem_vars_expr (e:expr) : identifier_set SymbolTag ≝
8match e with
9[ Expr ed ty ⇒
10    match ed with
11    [ Ederef e1 ⇒ gather_mem_vars_expr e1
12    | Eaddrof e1 ⇒ gather_mem_vars_addr e1
13    | Eunop _ e1 ⇒ gather_mem_vars_expr e1
14    | Ebinop _ e1 e2 ⇒ gather_mem_vars_expr e1 ∪
15                       gather_mem_vars_expr e2
16    | Ecast _ e1 ⇒ gather_mem_vars_expr e1
17    | Econdition e1 e2 e3 ⇒ gather_mem_vars_expr e1 ∪
18                            gather_mem_vars_expr e2 ∪
19                            gather_mem_vars_expr e3
20    | Eandbool e1 e2 ⇒ gather_mem_vars_expr e1 ∪
21                       gather_mem_vars_expr e2
22    | Eorbool e1 e2 ⇒ gather_mem_vars_expr e1 ∪
23                      gather_mem_vars_expr e2
24    | Efield e1 _ ⇒ gather_mem_vars_expr e1
25    | Ecost _ e1 ⇒ gather_mem_vars_expr e1
26    | _ ⇒ ∅
27    ]
28]
29and gather_mem_vars_addr (e:expr) : identifier_set SymbolTag ≝
30match e with
31[ Expr ed ty ⇒
32    match ed with
33    [ Evar x ⇒ { (x) }
34    | Ederef e1 ⇒ gather_mem_vars_expr e1
35    | Efield e1 _ ⇒ gather_mem_vars_addr e1
36    | _ ⇒ ∅ (* not an lvalue *)
37    ]
38].
39
40let rec gather_mem_vars_stmt (s:statement) : identifier_set SymbolTag ≝
41match s with
42[ Sskip ⇒ ∅
43| Sassign e1 e2 ⇒ gather_mem_vars_expr e1 ∪
44                  gather_mem_vars_expr e2
45| Scall oe1 e2 es ⇒ match oe1 with [ None ⇒ ∅ | Some e1 ⇒ gather_mem_vars_expr e1 ] ∪
46                    gather_mem_vars_expr e2 ∪
47                    (foldl ?? (λs,e. s ∪ gather_mem_vars_expr e) ∅ es)
48| Ssequence s1 s2 ⇒ gather_mem_vars_stmt s1 ∪
49                    gather_mem_vars_stmt s2
50| Sifthenelse e1 s1 s2 ⇒ gather_mem_vars_expr e1 ∪
51                         gather_mem_vars_stmt s1 ∪
52                         gather_mem_vars_stmt s2
53| Swhile e1 s1 ⇒ gather_mem_vars_expr e1 ∪
54                 gather_mem_vars_stmt s1
55| Sdowhile e1 s1 ⇒ gather_mem_vars_expr e1 ∪
56                   gather_mem_vars_stmt s1
57| Sfor s1 e1 s2 s3 ⇒ gather_mem_vars_stmt s1 ∪
58                     gather_mem_vars_expr e1 ∪
59                     gather_mem_vars_stmt s2 ∪
60                     gather_mem_vars_stmt s3
61| Sbreak ⇒ ∅
62| Scontinue ⇒ ∅
63| Sreturn oe1 ⇒ match oe1 with [ None ⇒ ∅ | Some e1 ⇒ gather_mem_vars_expr e1 ]
64| Sswitch e1 ls ⇒ gather_mem_vars_expr e1 ∪
65                  gather_mem_vars_ls ls
66| Slabel _ s1 ⇒ gather_mem_vars_stmt s1
67| Sgoto _ ⇒ ∅
68| Scost _ s1 ⇒ gather_mem_vars_stmt s1
69]
70and gather_mem_vars_ls (ls:labeled_statements) on ls : identifier_set SymbolTag ≝
71match ls with
72[ LSdefault s1 ⇒ gather_mem_vars_stmt s1
73| LScase _ _ s1 ls1 ⇒ gather_mem_vars_stmt s1 ∪
74                      gather_mem_vars_ls ls1
75].
76
77(* Defines where a variable should be allocated. *)
78inductive var_type : Type[0] ≝
79| Global : region → var_type  (* A global, allocated statically in a given region (which one ???)  *)
80| Stack  : nat → var_type     (* On the stack, at a given height *)
81| Local  : var_type           (* Locally (hopefully, in a register) *)
82.
83
84(* A map associating each variable identifier to its allocation mode and its type. *)
85definition var_types ≝ identifier_map SymbolTag (var_type × type).
86
87axiom UndeclaredIdentifier : String.
88
89definition lookup' ≝
90λvars:var_types.λid. opt_to_res … [MSG UndeclaredIdentifier; CTX ? id] (lookup ?? vars id).
91
92(* Assert that an identifier is a local variable with the given typ. *)
93definition local_id : var_types → ident → typ → Prop ≝
94λvars,id,t. match lookup' vars id with [ OK vt ⇒ match (\fst vt) with [ Global _ ⇒ False | _ ⇒ t = typ_of_type (\snd vt) ] | _ ⇒ False ].
95
96(* Note that the semantics allows locals to shadow globals.
97   Parameters start out as locals, but get stack allocated if their address
98   is taken.  We will add code to store them if that's the case.
99 *)
100
101(* Some kind of data is never allocated in registers, even if it fits, typically structured data. *)
102definition always_alloc : type → bool ≝
103λt. match t with
104[ Tarray _ _ ⇒ true
105| Tstruct _ _ ⇒ true
106| Tunion _ _ ⇒ true
107| _ ⇒ false
108].
109
110(* This builds a [var_types] map characterizing the allocation mode, of variables,
111 * and it returns a stack usage for the function (in bytes, according to [sizeof]) *)
112definition characterise_vars : list (ident×region×type) → function → var_types × nat ≝
113λglobals, f.
114  (* globals are added into a map, with var_type Global, region π_2(idrt) and type π_3(idrt) *)
115  let m ≝ foldr ?? (λidrt,m. add ?? m (\fst (\fst idrt)) 〈Global (\snd (\fst idrt)), \snd idrt〉) (empty_map ??) globals in
116  (* variables in the body of the function are gathered in [mem_vars] *)
117  let mem_vars ≝ gather_mem_vars_stmt (fn_body f) in
118  (* iterate on the parameters and local variables of the function, with a tuple (map, stack_high) as an accumulator *)
119  let 〈m,stacksize〉 ≝ foldr ?? (λv,ms.
120    let 〈m,stack_high〉 ≝ ms in
121    let 〈id,ty〉 ≝ v in         
122    let 〈c,stack_high〉 ≝
123      (* if the (local, parameter) variable is of a compound type OR if its adress is taken, we allocate it on the stack. *)
124      if always_alloc ty ∨ id ∈ mem_vars then
125        〈Stack stack_high,stack_high + sizeof ty〉
126      else
127        〈Local, stack_high〉
128    in
129      〈add ?? m id 〈c, ty〉, stack_high〉) 〈m,0〉 (fn_params f @ fn_vars f) in
130  〈m,stacksize〉.
131
132(* A local variable id' status is not modified by the removal of a global variable id : id' is still local *)
133lemma local_id_add_global : ∀vars,id,r,t,id',t'.
134  local_id (add ?? vars id 〈Global r, t〉) id' t' → local_id vars id' t'.
135#var #id #r #t #id' #t'
136whd in ⊢ (% → ?); whd in ⊢ (match % with [ _ ⇒ ? | _ ⇒ ?] → ?);
137cases (identifier_eq ? id id')
138[ #E >E >lookup_add_hit whd in ⊢ (% → ?); *
139| #NE >lookup_add_miss /2/
140] qed.
141
142(* If I add a variable id ≠ id', then id' is still local *)
143lemma local_id_add_miss : ∀vars,id,vt,id',t'.
144  id ≠ id' → local_id (add ?? vars id vt) id' t' → local_id vars id' t'.
145#vars #id #vt #id' #t' #NE
146whd in ⊢ (% → %);
147whd in ⊢ (match % with [ _ ⇒ ? | _ ⇒ ? ] → match % with [ _ ⇒ ? | _ ⇒ ? ]);
148>lookup_add_miss
149[ #H @H | /2/ ]
150qed.
151
152(* After characterise_vars, a variable in the resulting map is either a global or a "local"(register or stack allocated) *)
153lemma characterise_vars_src : ∀gl,f,vars,n.
154  characterise_vars gl f = 〈vars,n〉 →
155  ∀id. present ?? vars id →
156   (∃r,ty. lookup' vars id = OK ? 〈Global r,ty〉 ∧ Exists ? (λx.x = 〈〈id,r〉,ty〉) gl) ∨
157   ∃t.local_id vars id t.
158#globals #f
159whd in ⊢ (∀_.∀_.??%? → ?);
160elim (fn_params f @ fn_vars f)
161[ #vars #n whd in ⊢ (??%? → ?); #E destruct #i #H %1
162  elim globals in H ⊢ %;
163  [ normalize * #H cases (H (refl ??))
164  | * * #id #rg #ty #tl #IH #H
165    cases (identifier_eq ? i id)
166    [ #E <E %{rg} %{ty} % [ whd in ⊢ (??%?); >lookup_add_hit // | %1 // ]
167    | #NE cases (IH ?)
168      [ #rg' * #ty' * #H1 #H2 %{rg'} %{ty'} %
169        [ whd in ⊢ (??%?); >lookup_add_miss  [ @H1 | @NE ]
170        | %2 @H2
171        ]
172      | whd in H ⊢ %; >lookup_add_miss in H; //
173      ]
174    ]
175  ]
176| * #id #ty #tl #IH #vars #n whd in ⊢ (??(match % with [ _ ⇒ ? ])? → ?); #E #i
177  #H >(contract_pair var_types nat ?) in E;
178  whd in ⊢ (??(match ? with [ _ ⇒ (λ_.λ_.%) ])? → ?);
179  cases (always_alloc ty ∨ id ∈ ?) whd in ⊢ (??(match ? with [ _ ⇒ (λ_.λ_.%) ])? → ?);
180  #H' lapply (extract_pair ???????? H') -H' * #m0 * #n0 * #EQ #EQ2
181  cases (identifier_eq ? i id)
182  [ 1,3: #E' <E' in EQ2:%; #EQ2 %2 %{(typ_of_type ty)}
183         destruct (EQ2) whd whd in ⊢ (match % with [_ ⇒ ? | _ ⇒ ?]);
184         >lookup_add_hit @refl
185  | *: #NE cases (IH m0 n0 ? i ?)
186    [ 1,5: * #rg' * #ty' * #H1 #H2 %1 %{rg'} %{ty'} % //
187           destruct (EQ2) whd in ⊢ (??%?); >lookup_add_miss try @NE @H1
188    | 2,6: * #t #H1 %2 %{t} destruct (EQ2) whd whd in ⊢ (match % with [_ ⇒ ?|_ ⇒ ?]);
189           >lookup_add_miss //
190    | 3,7: <EQ @refl
191    | *: destruct (EQ2) whd in H; >lookup_add_miss in H; //
192    ]
193  ]
194] qed.
195
196(* A local variable in a function is either a parameter or a "local" (:=register or stack alloc'd)
197 * variable, with the right type *)
198lemma characterise_vars_all : ∀l,f,vars,n.
199  characterise_vars l f = 〈vars,n〉 →
200  ∀i,t. local_id vars i t →
201        Exists ? (λx.\fst x = i ∧ typ_of_type (\snd x) = t) (fn_params f @ fn_vars f).
202#globals #f
203whd in ⊢ (∀_.∀_.??%? → ?);
204elim (fn_params f @ fn_vars f)
205[ #vars #n whd in ⊢ (??%? → ?); #E destruct #i #t #H @False_ind
206  elim globals in H;
207  [ normalize //
208  | * * #id #rg #t #tl #IH whd in ⊢ (?%?? → ?); #H @IH @(local_id_add_global … H)
209  ]
210| * #id #ty #tl #IH #vars #n whd in ⊢ (??(match % with [ _ ⇒ ? ])? → ?); #E #i #t
211
212  #H >(contract_pair var_types nat ?) in E;
213  whd in ⊢ (??(match ? with [ _ ⇒ (λ_.λ_.%) ])? → ?);
214  cases (always_alloc ty ∨ id ∈ ?) whd in ⊢ (??(match ? with [ _ ⇒ (λ_.λ_.%) ])? → ?);
215  #H' lapply (extract_pair ???????? H') -H' * #m0 * #n0 * #EQ #EQ2
216
217  cases (identifier_eq ? id i)
218  [ 1,3: #E' >E' in EQ2:%; #EQ2 % %
219    [ 1,3: @refl
220    | *: destruct (EQ2) change with (add ?????) in H:(?%??);
221      whd in H; whd in H:(match % with [_ ⇒ ?|_ ⇒ ?]); >lookup_add_hit in H;
222      whd in ⊢ (% → ?); #E'' >E'' @refl
223    ]
224  | *: #NE %2 @(IH m0 n0)
225    [ 1,3: @sym_eq whd in ⊢ (???(match ?????% with [ _ ⇒ ? ])); >contract_pair @EQ
226    | 2,4: destruct (EQ2) @(local_id_add_miss … H) @NE
227    ]
228  ]
229] qed.
230
231(* The map generated by characterise_vars is "correct" wrt the fresh ident generator of tag [u],
232   i.e. by generating fresh idents with u, we risk no collision with the idents in the map domain. *)
233lemma characterise_vars_fresh : ∀gl,f,vars,n,u.
234  characterise_vars gl f = 〈vars,n〉 →              (* If we generate a map ... *)
235  globals_fresh_for_univ ? gl u →                  (* and the globals are out of the idents generated by u *)
236  fn_fresh_for_univ f u →                          (* and the variables of the function f are cool with u too ... *)
237  fresh_map_for_univ … vars u.                     (* then there won't be collisions between the map and idents made from u *)
238#gl #f #vars #n #u #CH #GL #FN
239#id #H
240cases (characterise_vars_src … CH … H)
241[ * #rg * #ty * #H1 #H2
242  cases (Exists_All … H2 GL) * * #id' #rg' #ty' * #E #H destruct //
243| * #t #H lapply (characterise_vars_all … CH id t H) #EX
244  cases (Exists_All … EX FN) * #id' #ty' * * #E1 #E2 #H' -H destruct //
245] qed.
246
247include "Cminor/syntax.ma".
248include "common/Errors.ma".
249
250alias id "CMexpr" = "cic:/matita/cerco/Cminor/syntax/expr.ind(1,0,0)".
251
252axiom BadlyTypedAccess : String.
253axiom BadLvalue : String.
254axiom MissingField : String.
255
256(* type_should_eq enforces that two types are equal and eliminates this equality by
257   transporting P ty1 to P ty2. If ty1 != ty2, then Error *)
258definition type_should_eq : ∀ty1,ty2. ∀P:type → Type[0]. P ty1 → res (P ty2) ≝
259λty1,ty2,P,p.
260  do E ← assert_type_eq ty1 ty2;
261  OK ? (match E return λx.λ_. P ty1 → P x with [ refl ⇒ λp.p ] p). 
262
263(* same gig for regions *)
264definition region_should_eq : ∀r1,r2. ∀P:region → Type[0]. P r1 → res (P r2).
265* * #P #p try @(OK ? p) @(Error ? (msg TypeMismatch))
266qed.
267
268(* same gig for AST typs *)
269definition typ_should_eq : ∀ty1,ty2. ∀P:typ → Type[0]. P ty1 → res (P ty2).
270* [ #sz1 #sg1 | | #sz1 ]
271* [ 1,5,9: | *: #a #b try #c try #d @(Error ? (msg TypeMismatch)) ]
272[ *; cases sz1 [ 1,5,9: | *: #a #b #c @(Error ? (msg TypeMismatch)) ]
273  *; cases sg1 #P #p try @(OK ? p) @(Error ? (msg TypeMismatch))
274| #P #p @(OK ? p)
275| *; cases sz1 #P #p try @(OK ? p) @(Error ? (msg TypeMismatch))
276] qed.
277
278alias id "CLunop" = "cic:/matita/cerco/Clight/Csyntax/unary_operation.ind(1,0,0)".
279alias id "CMunop" = "cic:/matita/cerco/common/FrontEndOps/unary_operation.ind(1,0,0)".
280
281(* XXX: For some reason matita refuses to pick the right one unless forced. *)
282alias id "CMnotbool" = "cic:/matita/cerco/common/FrontEndOps/unary_operation.con(0,3,0)".
283
284(* Translates a Clight unary operation into a Cminor one, while checking
285 * that the domain and codomain types are consistent. *)
286definition translate_unop : ∀t,t':typ. CLunop → res (CMunop t t') ≝
287λt,t'.λop:CLunop.
288  match op with
289  [ Onotbool ⇒
290      match t return λt. res (CMunop t t') with
291      [ ASTint sz sg ⇒
292          match t' return λt'. res (CMunop ? t') with
293          [ ASTint sz' sg' ⇒ OK ? (CMnotbool ????)
294          | _ ⇒ Error ? (msg TypeMismatch)
295          ]
296      | ASTptr ⇒
297          match t' return λt'. res (CMunop ? t') with
298          [ ASTint sz' sg' ⇒ OK ? (CMnotbool ????)
299          | _ ⇒ Error ? (msg TypeMismatch)
300          ]
301      | _ ⇒ Error ? (msg TypeMismatch)
302      ]
303  | Onotint ⇒
304      match t' return λt'. res (CMunop t t') with
305      [ ASTint sz sg ⇒ typ_should_eq ?? (λt. CMunop t (ASTint ??)) (Onotint sz sg)
306      | _ ⇒ Error ? (msg TypeMismatch)
307      ]
308  | Oneg ⇒
309      match t' return λt'. res (CMunop t t') with
310      [ ASTint sz sg ⇒ typ_should_eq ?? (λt.CMunop t (ASTint ??)) (Onegint sz sg)
311      | ASTfloat sz ⇒ typ_should_eq ?? (λt.CMunop t (ASTfloat sz)) (Onegf sz)
312      | _ ⇒ Error ? (msg TypeMismatch)
313      ]
314  ]. @I qed.
315
316(* Translates a Clight addition into a Cminor one. Four cases to consider :
317  - integer/integer add
318  - fp/fp add
319  - pointer/integer
320  - integer/pointer.
321  Consistency of the type is enforced by explicit checks.
322*)
323
324(* First, how to get rid of a abstract-away pointer or array type *)
325definition fix_ptr_type : ∀ty,n. expr (typ_of_type (ptr_type ty n)) → expr ASTptr ≝
326λty,n,e. e⌈expr (typ_of_type (ptr_type ty n)) ↦ expr ASTptr⌉.
327cases n //
328qed.
329
330definition translate_add ≝
331λty1,ty2,ty'.
332let ty1' ≝ typ_of_type ty1 in
333let ty2' ≝ typ_of_type ty2 in
334match classify_add ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
335[ add_case_ii sz sg ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Oadd ??) e1 e2)
336| add_case_ff sz ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Oaddf sz) e1 e2)
337(* XXX we cast up to I16 Signed to prevent overflow, but often we could use I8 *)
338| add_case_pi n ty sz sg ⇒
339    λe1,e2. typ_should_eq ??? (Op2 ??? (Oaddp I16) (fix_ptr_type … e1) (Op2 ??? (Omul I16 Signed) (Op1 ?? (Ocastint sz sg I16 Signed) e2) (Cst ? (Ointconst I16 Signed (repr ? (sizeof ty))))))
340| add_case_ip n sz sg ty ⇒
341    λe1,e2. typ_should_eq ??? (Op2 ??? (Oaddp I16) (fix_ptr_type … e2) (Op2 ??? (Omul I16 Signed) (Op1 ?? (Ocastint sz sg I16 Signed) e1) (Cst ? (Ointconst I16 Signed (repr ? (sizeof ty))))))
342| add_default _ _ ⇒ λe1,e2. Error ? (msg TypeMismatch)
343].
344
345
346definition translate_sub ≝
347λty1,ty2,ty'.
348let ty1' ≝ typ_of_type ty1 in
349let ty2' ≝ typ_of_type ty2 in
350match classify_sub ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
351[ sub_case_ii sz sg ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Osub ??) e1 e2)
352| sub_case_ff sz ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Osubf sz) e1 e2)
353(* XXX could optimise cast as above *)
354| sub_case_pi n ty sz sg ⇒
355    λe1,e2. typ_should_eq ??? (Op2 ??? (Osubpi I16) (fix_ptr_type … e1) (Op2 ??? (Omul I16 Signed) (Op1 ?? (Ocastint sz sg I16 Signed) e2) (Cst ? (Ointconst I16 Signed (repr ? (sizeof ty))))))
356(* XXX check in detail? *)
357| sub_case_pp n1 n2 ty1 ty2 ⇒
358    λe1,e2. match ty' return λty'. res (CMexpr (typ_of_type ty')) with
359    [ Tint sz sg ⇒ OK ? (Op1 ?? (Ocastint I16 Signed sz sg) (Op2 ??? (Odiv I16) (Op2 ??? (Osubpp I16) (fix_ptr_type … e1) (fix_ptr_type ?? e2)) (Cst ? (Ointconst I16 Signed (repr ? (sizeof ty2))))))
360    | _ ⇒ Error ? (msg TypeMismatch)
361    ]
362| sub_default _ _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
363].
364
365definition translate_mul ≝
366λty1,ty2,ty'.
367let ty1' ≝ typ_of_type ty1 in
368let ty2' ≝ typ_of_type ty2 in
369match classify_aop ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
370[ aop_case_ii sz sg ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omul …) e1 e2)
371| aop_case_ff sz ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omulf …) e1 e2)
372| aop_default _ _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
373].
374
375definition translate_div ≝
376λty1,ty2,ty'.
377let ty1' ≝ typ_of_type ty1 in
378let ty2' ≝ typ_of_type ty2 in
379match classify_aop ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
380[ aop_case_ii sz sg ⇒
381    match sg return λsg. CMexpr (ASTint sz sg) → CMexpr (ASTint sz sg) → res (CMexpr (typ_of_type ty')) with
382    [ Unsigned ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Odivu …) e1 e2)
383    | Signed ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Odiv …) e1 e2)
384    ]
385| aop_case_ff sz ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Odivf …) e1 e2)
386| aop_default _ _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
387].
388
389definition translate_mod ≝
390λty1,ty2,ty'.
391let ty1' ≝ typ_of_type ty1 in
392let ty2' ≝ typ_of_type ty2 in
393match classify_aop ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
394[ aop_case_ii sz sg ⇒
395    match sg return λsg. CMexpr (ASTint sz sg) → CMexpr (ASTint sz sg) → res (CMexpr (typ_of_type ty')) with
396    [ Unsigned ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omodu …) e1 e2)
397    | Signed ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omod …) e1 e2)
398    ]
399(* no float case *)
400| _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
401].
402
403definition translate_shr ≝
404λty1,ty2,ty'.
405let ty1' ≝ typ_of_type ty1 in
406let ty2' ≝ typ_of_type ty2 in
407match classify_aop ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
408[ aop_case_ii sz sg ⇒
409    match sg return λsg. CMexpr (ASTint sz sg) → CMexpr (ASTint sz sg) → res (CMexpr (typ_of_type ty')) with
410    [ Unsigned ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omodu …) e1 e2)
411    | Signed ⇒ λe1,e2. typ_should_eq ??? (Op2 ??? (Omod …) e1 e2)
412    ]
413(* no float case *)
414| _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
415].
416
417definition complete_cmp : ∀ty'. CMexpr (ASTint I8 Unsigned) → res (CMexpr (typ_of_type ty')) ≝
418λty',e.
419match ty' return λty'. res (CMexpr (typ_of_type ty')) with
420[ Tint sz sg ⇒ OK ? (Op1 ?? (Ocastint I8 Unsigned sz sg) e)
421| _ ⇒ Error ? (msg TypeMismatch)
422].
423
424definition translate_cmp ≝
425λc,ty1,ty2,ty'.
426let ty1' ≝ typ_of_type ty1 in
427let ty2' ≝ typ_of_type ty2 in
428match classify_cmp ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
429[ cmp_case_ii sz sg ⇒
430    match sg return λsg. CMexpr (ASTint sz sg) → CMexpr (ASTint sz sg) → res (CMexpr (typ_of_type ty')) with
431    [ Unsigned ⇒ λe1,e2. complete_cmp ty' (Op2 ??? (Ocmpu … c) e1 e2)
432    | Signed ⇒ λe1,e2. complete_cmp ty' (Op2 ??? (Ocmp … c) e1 e2)
433    ]
434| cmp_case_pp n ty ⇒
435    λe1,e2. complete_cmp ty' (Op2 ??? (Ocmpp … c) (fix_ptr_type … e1) (fix_ptr_type … e2))
436| cmp_case_ff sz ⇒ λe1,e2. complete_cmp ty' (Op2 ??? (Ocmpf … c) e1 e2)
437| cmp_default _ _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
438].
439
440definition translate_misc_aop ≝
441λty1,ty2,ty',op.
442let ty1' ≝ typ_of_type ty1 in
443let ty2' ≝ typ_of_type ty2 in
444match classify_aop ty1 ty2 return λty1,ty2.λ_. CMexpr (typ_of_type ty1) → CMexpr (typ_of_type ty2) → res (CMexpr (typ_of_type ty')) with
445[ aop_case_ii sz sg ⇒ λe1,e2. typ_should_eq ??? (Op2 ?? (ASTint sz sg) (op sz sg) e1 e2)
446| _ ⇒ λ_.λ_. Error ? (msg TypeMismatch)
447].
448
449definition translate_binop : binary_operation → type → CMexpr ? → type → CMexpr ? → type → res (CMexpr ?) ≝
450λop,ty1,e1,ty2,e2,ty.
451let ty' ≝ typ_of_type ty in
452match op with
453[ Oadd ⇒ translate_add ty1 ty2 ty e1 e2
454| Osub ⇒ translate_sub ty1 ty2 ty e1 e2
455| Omul ⇒ translate_mul ty1 ty2 ty e1 e2
456| Omod ⇒ translate_mod ty1 ty2 ty e1 e2
457| Odiv ⇒ translate_div ty1 ty2 ty e1 e2
458| Oand ⇒ translate_misc_aop ty1 ty2 ty Oand e1 e2
459| Oor  ⇒ translate_misc_aop ty1 ty2 ty Oor e1 e2
460| Oxor ⇒ translate_misc_aop ty1 ty2 ty Oxor e1 e2
461| Oshl ⇒ translate_misc_aop ty1 ty2 ty Oshl e1 e2
462| Oshr ⇒ translate_shr ty1 ty2 ty e1 e2
463| Oeq ⇒ translate_cmp Ceq ty1 ty2 ty e1 e2
464| One ⇒ translate_cmp Cne ty1 ty2 ty e1 e2
465| Olt ⇒ translate_cmp Clt ty1 ty2 ty e1 e2
466| Ogt ⇒ translate_cmp Cgt ty1 ty2 ty e1 e2
467| Ole ⇒ translate_cmp Cle ty1 ty2 ty e1 e2
468| Oge ⇒ translate_cmp Cge ty1 ty2 ty e1 e2
469].
470
471lemma typ_equals : ∀t1,t2. ∀P:∀t. expr t → Prop. ∀v1,v2.
472  typ_should_eq t1 t2 expr v1 = OK ? v2 →
473  P t1 v1 →
474  P t2 v2.
475* [ * * | | * ]
476* try * try *
477#P #v1 #v2 #E whd in E:(??%?); destruct
478#H @H
479qed.
480
481lemma unfix_ptr_type : ∀ty,n,e.∀P:∀t. expr t → Prop.
482  P (typ_of_type (ptr_type ty n)) e →
483  P ASTptr (fix_ptr_type ty n e).
484#ty * [ 2: #n ] #e #P #H @H
485qed.
486
487(* Recall that [expr_vars], defined in Cminor/Syntax.ma, asserts a predicate on
488  all the variables of a program. [translate_binop_vars], given
489  a predicate verified for all variables of subexprs e1 and e2, produces
490  a proof that all variables of [translate_binop op _ e1 _ e2 _] satisfy this
491  predicate. *)
492
493lemma translate_binop_vars : ∀P,op,ty1,e1,ty2,e2,ty,e.
494  expr_vars ? e1 P →
495  expr_vars ? e2 P →
496  translate_binop op ty1 e1 ty2 e2 ty = OK ? e →
497  expr_vars ? e P.
498#P * #ty1 #e1 #ty2 #e2 #ty #e #H1 #H2
499whd in ⊢ (??%? → ?);
500[ inversion (classify_add ty1 ty2) in ⊢ ?;
501  [ #sz #sg #E1 #E2 #E3 destruct >E3 #E4 -E3 change with (typ_should_eq ???? = OK ??) in E4;
502    @(typ_equals … E4) % //
503  | #sz #E1 #E2 #E3 destruct >E3 #E4
504    @(typ_equals … E4) % //
505  | #n #ty0 #sz #sg #E1 #E2 #E3 destruct >E3 #E4
506    @(typ_equals … E4) -E4 -E3 % [ @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H1)| % // ]
507  | #n #sz #sg #ty0 #E1 #E2 #E3 destruct >E3 #E4
508    @(typ_equals … E4) % [ @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H2)| % // ]
509  | #ty1' #ty2' #E1 #E2 #E3 destruct >E3 #E4 whd in E4:(??%?); destruct
510  ]
511| inversion (classify_sub ty1 ty2) in ⊢ ?;
512  [ #sz #sg #E1 #E2 #E3 destruct >E3 #E4
513    @(typ_equals … E4) % //
514  | #sz #E1 #E2 #E3 destruct >E3 #E4
515    @(typ_equals … E4) % //
516  | #n #ty0 #sz #sg #E1 #E2 #E3 destruct >E3 #E4
517    @(typ_equals … E4) % [ @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H1)| % // ]
518  | #n1 #n2 #ty1' #ty2' #E1 #E2 #E3 destruct >E3
519    whd in ⊢ (??%? → ?); cases ty in e ⊢ %;
520    [ 2: #sz #sg #e #E4 | 4: #ty #e #E4 | 5: #ty' #n' #e #E4
521    | *: normalize #X1 #X2 try #X3 try #X4 destruct
522    ] whd in E4:(??%?); destruct % // %
523    [ @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H1) | @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H2) ]
524  | #ty1' #ty2' #E1 #E2 #E3 destruct >E3 #E4 whd in E4:(??%?); destruct
525  ]
526| 3,4,5,6,7,8,9,10: inversion (classify_aop ty1 ty2) in ⊢ ?;
527  (* Note that some cases require a split on signedness of integer type. *)
528  [ 1,4,7,10,13,16,19,22: #sz * #E1 #E2 #E3 destruct >E3 #E4
529    @(typ_equals … E4) % //
530  | 2,5: #sz #E1 #E2 #E3 destruct >E3 #E4
531    @(typ_equals … E4) % //
532  | 8,11,14,17,20,23: #sz #E1 #E2 #E3 destruct >E3 #E4 whd in E4:(??%?); destruct
533  | 3,6,9,12,15,18,21,24: #ty1' #ty2' #E1 #E2 #E3 destruct >E3 #E4 whd in E4:(??%?); destruct
534  ]
535| 11,12,13,14,15,16: inversion (classify_cmp ty1 ty2) in ⊢ ?;
536  [ 1,5,9,13,17,21: #sz * #E1 #E2 #E3 destruct >E3
537  | 2,6,10,14,18,22: #n #ty' #E1 #E2 #E3 destruct >E3
538  | 3,7,11,15,19,23: #sz #E1 #E2 #E3 destruct >E3
539  | *: #ty1' #ty2' #E1 #E2 #E3 destruct >E3 #E4 whd in E4:(??%?); @⊥ destruct
540  ] whd in ⊢ (??%? → ?); cases ty in e ⊢ %;
541  try (normalize #X1 #X2 try #X3 try #X4 try #X5 destruct #FAIL)
542  #sz #sg #e #E4
543  whd in E4:(??%?); destruct %
544  [ 25,27,29,31,33,35: @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H1)
545  | 26,28,30,32,34,36: @(unfix_ptr_type ??? (λt,e. expr_vars t e P) H2)
546  | *: //
547  ]
548] qed.
549
550
551(* We'll need to implement proper translation of pointers if we really do memory
552   spaces.
553(* This function performs leibniz-style subst if r1 = r2, and fails otherwise. *)
554definition check_region : ∀r1:region. ∀r2:region. ∀P:region → Type[0]. P r1 → res (P r2) ≝
555λr1,r2,P.
556  match r1 return λx.P x → res (P r2) with
557  [ Any ⇒   match r2 return λx.P Any → res (P x) with [ Any ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
558  | Data ⇒  match r2 return λx.P Data → res (P x) with [ Data ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
559  | IData ⇒ match r2 return λx.P IData → res (P x) with [ IData ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
560  | PData ⇒ match r2 return λx.P PData → res (P x) with [ PData ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
561  | XData ⇒ match r2 return λx.P XData → res (P x) with [ XData ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
562  | Code ⇒  match r2 return λx.P Code → res (P x) with [ Code ⇒ OK ? | _ ⇒ λ_.Error ? (msg TypeMismatch) ]
563  ].
564
565(* Simple application of [check_region] to translate between terms. *)
566definition translate_ptr : ∀P,r1,r2. (Σe:CMexpr (ASTptr r1). expr_vars ? e P) → res (Σe':CMexpr (ASTptr r2).expr_vars ? e' P) ≝
567λP,r1,r2,e. check_region r1 r2 (λr.Σe:CMexpr (ASTptr r).expr_vars ? e P) e.
568*)
569axiom FIXME : String.
570
571(* Given a source and target type, translate an expession of type source to type target *)
572definition translate_cast : ∀P. ∀ty1:type.∀ty2:type. (Σe:CMexpr (typ_of_type ty1). expr_vars ? e P) → res (Σe':CMexpr (typ_of_type ty2). expr_vars ? e' P) ≝
573λP,ty1,ty2.
574match ty1 return λx.(Σe:CMexpr (typ_of_type x). expr_vars ? e P) → ? with
575[ Tint sz1 sg1 ⇒ λe.
576    match ty2 return λx.res (Σe':CMexpr (typ_of_type x).expr_vars ? e' P) with
577    [ Tint sz2 sg2 ⇒ OK ? (Op1 ?? (Ocastint ? sg1 sz2 ?) e)
578    | Tfloat sz2 ⇒ OK ? (Op1 ?? (match sg1 with [ Unsigned ⇒ Ofloatofintu ?? | _ ⇒ Ofloatofint ??]) e)
579    | Tpointer _ ⇒ OK ? (Op1 ?? (Optrofint ??) e)
580    | Tarray _ _ ⇒ OK ? (Op1 ?? (Optrofint ??) e)
581    | _ ⇒ Error ? (msg TypeMismatch)
582    ]
583| Tfloat sz1 ⇒ λe.
584    match ty2 return λx.res (Σe':CMexpr (typ_of_type x).expr_vars ? e' P) with
585    [ Tint sz2 sg2 ⇒ OK ? «Op1 ?? (match sg2 with [ Unsigned ⇒ Ointuoffloat ? sz2 | _ ⇒ Ointoffloat ? sz2 ]) e, ?»
586    | Tfloat sz2 ⇒ Error ? (msg FIXME) (* OK ? «Op1 ?? (Oid ?) e, ?» (* FIXME *) *)
587    | _ ⇒ Error ? (msg TypeMismatch)
588    ]
589| Tpointer _ ⇒ λe. (* will need changed for memory regions *)
590    match ty2 return λx.res (Σe':CMexpr (typ_of_type x). expr_vars ? e' P) with
591    [ Tint sz2 sg2 ⇒ OK ? «Op1 ?? (Ointofptr sz2 ?) e, ?»
592    | Tarray _ _ ⇒ (*translate_ptr ? r1 r2 e*) OK ? e
593    | Tpointer _ ⇒ OK ? e
594    | _ ⇒ Error ? (msg TypeMismatch)
595    ]
596| Tarray _ _ ⇒ λe. (* will need changed for memory regions *)
597    match ty2 return λx.res (Σe':CMexpr (typ_of_type x).expr_vars ? e' P) with
598    [ Tint sz2 sg2 ⇒ OK ? «Op1 ASTptr (ASTint sz2 sg2) (Ointofptr sz2 ?) e, ?»
599    | Tarray _ _ ⇒ OK ? e
600    | Tpointer _ ⇒ OK ? e
601    | _ ⇒ Error ? (msg TypeMismatch)
602    ]
603| _ ⇒ λ_. Error ? (msg TypeMismatch)
604]. whd normalize nodelta @pi2
605qed.
606
607(* Translate Clight exprs into Cminor ones.
608  Arguments :
609  - vars:var_types, an environment mapping each variable to a couple (allocation mode, type)
610  - e:expr, the expression to be converted
611  Result : res (Σe':CMexpr (typ_of_type (typeof e)). expr_vars ? e' (local_id vars))
612  that is, either
613  . an error
614  . an expression e', matching the type of e, such that e' respect the property that all variables
615    in it are not global. In effect, [translate_expr] will replace global variables by constant symbols.
616*)
617let rec translate_expr (vars:var_types) (e:expr) on e : res (Σe':CMexpr (typ_of_type (typeof e)). expr_vars ? e' (local_id vars)) ≝
618match e return λe. res (Σe':CMexpr (typ_of_type (typeof e)). expr_vars ? e' (local_id vars)) with
619[ Expr ed ty ⇒
620  match ed with
621  [ Econst_int sz i ⇒
622      match ty return λty. res (Σe':CMexpr (typ_of_type ty).  expr_vars ? e' (local_id vars)) with
623      [ Tint sz' sg ⇒ intsize_eq_elim' sz sz' (λsz,sz'. res (Σe':CMexpr (typ_of_type (Tint sz' sg)). expr_vars ? e' (local_id vars)))
624                        (OK ? «Cst ? (Ointconst sz sg i), ?»)
625                        (Error ? (msg TypeMismatch))
626      | _ ⇒ Error ? (msg TypeMismatch)
627      ]
628  | Econst_float f ⇒
629      match ty return λty. res (Σe':CMexpr (typ_of_type ty). ?) with
630      [ Tfloat sz ⇒ OK ? «Cst ? (Ofloatconst sz f), ?»
631      | _ ⇒ Error ? (msg TypeMismatch)
632      ]
633  | Evar id ⇒
634      do 〈c,t〉 as E ← lookup' vars id; (* E is an equality proof of the shape "lookup' vars id = Ok <c,t>" *)
635      match c return λx.? = ? → res (Σe':CMexpr ?. ?) with
636      [ Global r ⇒ λ_.
637          (* We are accessing a global variable in an expression. Its Cminor counterpart also depends on
638             its access mode:
639             - By_value q, where q is a memory chunk specification (whitch should match the type of the global)
640             - By_reference, and we only take the adress of the variable
641             - By_nothing : error
642           *)
643          match access_mode ty return λt.λ_. res (Σe':CMexpr t. expr_vars ? e' (local_id vars)) with
644          [ By_value t ⇒ OK ? «Mem t (Cst ? (Oaddrsymbol id 0)), ?» (* Mem is "load" in compcert *)
645          | By_reference ⇒ OK ? «Cst ? (Oaddrsymbol id 0), ?»
646          | By_nothing _ ⇒ Error ? [MSG BadlyTypedAccess; CTX ? id]
647          ]
648      | Stack n ⇒ λE.
649          (* We have decided that the variable should be allocated on the stack,
650           * because its adress was taken somewhere or becauste it's a structured data. *)
651          match access_mode ty return λt.λ_. res (Σe':CMexpr t. expr_vars ? e' (local_id vars)) with
652          [ By_value t ⇒ OK ? «Mem t (Cst ? (Oaddrstack n)), ?»
653          | By_reference ⇒ (*match r return λr. res (Σe':CMexpr (ASTptr r). ?) with
654                             [ Any ⇒*) OK ? «Cst ? (Oaddrstack n), ?» (*
655                             | _ ⇒ Error  ? [MSG BadlyTypedAccess; CTX ? id]
656                             ]*)
657          | By_nothing _ ⇒ Error ? [MSG BadlyTypedAccess; CTX ? id]
658          ]
659          (* This is a local variable. Keep it as an identifier in the Cminor code, ensuring that the type of the original expr and of ty match. *)
660      | Local ⇒ λE. type_should_eq t ty (λt.Σe':CMexpr (typ_of_type t).expr_vars (typ_of_type t) e' (local_id vars))  («Id (typ_of_type t) id, ?»)
661      ] E
662  | Ederef e1 ⇒
663      do e1' ← translate_expr vars e1;
664      (* According to the way the data pointed to by e1 is accessed, the generated Cminor code will vary.
665        - if e1 is a kind of int* ptr, then we load ("Mem") the ptr returned by e1
666        - if e1 is a struct* or a function ptr, then we acess by reference, in which case we :
667           1) check the consistency of the regions in the type of e1 and in the access mode of its type
668           2) return directly the converted CMinor expression "as is" (TODO : what is the strange notation with the ceil function and the mapsto ?)
669      *)
670      match typ_of_type (typeof e1) return λx.(Σz:CMexpr x.expr_vars ? z (local_id vars)) → ? with
671      [ ASTptr ⇒ λe1'.
672          match access_mode ty return λt.λ_. res (Σe':CMexpr t. expr_vars ? e' (local_id vars)) with
673          [ By_value t ⇒ OK ? «Mem t (pi1 … e1'), ?»
674          | By_reference ⇒ OK ? e1'
675          | By_nothing _ ⇒ Error ? (msg BadlyTypedAccess)
676          ]
677      | _ ⇒ λ_. Error ? (msg TypeMismatch)
678      ] e1'
679  | Eaddrof e1 ⇒
680      do e1' ← translate_addr vars e1;
681      match typ_of_type ty return λx.res (Σz:CMexpr x.?) with
682      [ ASTptr ⇒ OK ? e1'
683(*          match e1' with
684          [ mk_DPair r1 e1' ⇒ region_should_eq r1 r ? e1'
685          ]*)
686      | _ ⇒ Error ? (msg TypeMismatch)
687      ]
688  | Eunop op e1 ⇒
689      do op' ← translate_unop (typ_of_type (typeof e1)) (typ_of_type ty) op;
690      do e1' ← translate_expr vars e1;
691      OK ? «Op1 ?? op' e1', ?»
692  | Ebinop op e1 e2 ⇒
693      do e1' ← translate_expr vars e1;
694      do e2' ← translate_expr vars e2;
695      do e' as E ← translate_binop op (typeof e1) e1' (typeof e2) e2' ty;
696      OK ? «e', ?»
697  | Ecast ty1 e1 ⇒
698      do e1' ← translate_expr vars e1;
699      do e' ← translate_cast ? (typeof e1) ty1 e1';
700      do e' ← typ_should_eq (typ_of_type ty1) (typ_of_type ty) ? e';
701      OK ? e'
702  | Econdition e1 e2 e3 ⇒
703      do e1' ← translate_expr vars e1;
704      do e2' ← translate_expr vars e2;
705      do e2' ← type_should_eq ? ty (λx.Σe:CMexpr (typ_of_type x).?) e2';
706      do e3' ← translate_expr vars e3;
707      do e3' ← type_should_eq ? ty (λx.Σe:CMexpr (typ_of_type x).?) e3';
708      match typ_of_type (typeof e1) return λx.(Σe1':CMexpr x. expr_vars ? e1' (local_id vars)) → ? with
709      [ ASTint _ _ ⇒ λe1'. OK ? «Cond ??? e1' e2' e3', ?»
710      | _ ⇒ λ_.Error ? (msg TypeMismatch)
711      ] e1'
712  | Eandbool e1 e2 ⇒
713      do e1' ← translate_expr vars e1;
714      do e2' ← translate_expr vars e2;
715      match ty return λty. res (Σe':CMexpr (typ_of_type ty). ?) with
716      [ Tint sz sg ⇒
717        do e2' ← type_should_eq ? (Tint sz sg) (λx.Σe:CMexpr (typ_of_type x).?) e2';
718        match typ_of_type (typeof e1) return λx.(Σe:CMexpr x. expr_vars ? e (local_id vars)) → res ? with
719        [ ASTint _ _ ⇒ λe1'. OK ? «Cond ??? e1' e2' (Cst ? (Ointconst sz sg (zero ?))), ?»
720        | _ ⇒ λ_.Error ? (msg TypeMismatch)
721        ] e1'
722      | _ ⇒ Error ? (msg TypeMismatch)
723      ]
724  | Eorbool e1 e2 ⇒
725      do e1' ← translate_expr vars e1;
726      do e2' ← translate_expr vars e2;
727      match ty return λty. res (Σe':CMexpr (typ_of_type ty). ?) with
728      [ Tint sz sg ⇒
729        do e2' ← type_should_eq ? (Tint sz sg) (λx.Σe:CMexpr (typ_of_type x).?) e2';
730        match typ_of_type (typeof e1) return λx.(Σe:CMexpr x. expr_vars ? e (local_id vars)) → ? with
731        [ ASTint _ _ ⇒ λe1'. OK ? «Cond ??? e1' (Cst ? (Ointconst sz sg (repr ? 1))) e2', ?»
732        | _ ⇒ λ_.Error ? (msg TypeMismatch)
733        ] e1'
734      | _ ⇒ Error ? (msg TypeMismatch)
735      ]
736  | Esizeof ty1 ⇒
737      match ty return λty. res (Σe':CMexpr (typ_of_type ty). ?) with
738      [ Tint sz sg ⇒ OK ? «Cst ? (Ointconst sz sg (repr ? (sizeof ty1))), ?»
739      | _ ⇒ Error ? (msg TypeMismatch)
740      ]
741  | Efield e1 id ⇒
742      match typeof e1 with
743      [ Tstruct _ fl ⇒
744          do e1' ← translate_addr vars e1;
745(*          match e1' with
746          [ mk_DPair r e1' ⇒*)
747            do off ← field_offset id fl;
748            match access_mode ty return λt.λ_. res (Σe':CMexpr t. expr_vars ? e' (local_id vars)) with
749            [ By_value t ⇒
750                OK ? «Mem t (Op2 ? (ASTint I16 Signed (* XXX efficiency? *)) ?
751                                   (Oaddp …) e1' (Cst ? (Ointconst I16 Signed (repr ? off)))),?»
752            | By_reference ⇒
753(*                do e1' ← region_should_eq r r' ? e1';*)
754                OK ? «Op2 ASTptr (ASTint I16 Signed (* XXX efficiency? *)) ASTptr
755                        (Oaddp …) e1' (Cst ? (Ointconst I16 Signed (repr ? off))),?»
756            | By_nothing _ ⇒ Error ? (msg BadlyTypedAccess)
757            ]
758      | Tunion _ _ ⇒
759          do e1' ← translate_addr vars e1;
760            match access_mode ty return λt.λ_. res (Σz:CMexpr t.?) with
761            [ By_value t ⇒ OK ? «Mem t e1', ?»
762            | By_reference ⇒ OK ? e1'
763            | By_nothing _ ⇒ Error ? (msg BadlyTypedAccess)
764            ]
765      | _ ⇒ Error ? (msg BadlyTypedAccess)
766      ]
767  | Ecost l e1 ⇒
768      do e1' ← translate_expr vars e1;
769      do e' ← OK ? «Ecost ? l e1',?»;
770      typ_should_eq (typ_of_type (typeof e1)) (typ_of_type ty) (λx.Σe:CMexpr x.?) e'
771  ]
772]
773
774(* Translate addr takes an expression e1, and returns a Cminor code computing the address of the result of [e1].   *)
775and translate_addr (vars:var_types) (e:expr) on e : res ((*𝚺r.*) Σe':CMexpr ASTptr. expr_vars ? e' (local_id vars)) ≝
776match e with
777[ Expr ed _ ⇒
778  match ed with
779  [ Evar id ⇒
780      do 〈c,t〉 ← lookup' vars id;
781      match c return λ_. res (Σz:CMexpr ASTptr.?) with
782      [ Global r ⇒ OK ? «Cst ? (Oaddrsymbol id 0), ?»
783      | Stack n ⇒ OK ? «Cst ? (Oaddrstack n), ?»
784      | Local ⇒ Error ? [MSG BadlyTypedAccess; CTX ? id] (* TODO: could rule out? *)
785      ]
786  | Ederef e1 ⇒
787      do e1' ← translate_expr vars e1;
788      match typ_of_type (typeof e1) return λx. (Σz:CMexpr x.expr_vars ? z (local_id vars)) → res (Σz:CMexpr ASTptr. expr_vars ? z (local_id vars)) with
789      [ ASTptr ⇒ λe1'.OK ? e1'
790      | _ ⇒ λ_.Error ? (msg BadlyTypedAccess)
791      ] e1'
792  | Efield e1 id ⇒
793      match typeof e1 with
794      [ Tstruct _ fl ⇒
795          do e1' ← translate_addr vars e1;
796          do off ← field_offset id fl;
797(*          match e1' with
798          [ mk_DPair r e1'' ⇒ OK (𝚺r:region.Σe:CMexpr (ASTptr r).?)*)
799             OK ? «Op2 ASTptr (ASTint I16 Signed (* FIXME inefficient?*)) ASTptr
800                   (Oaddp I16) e1' (Cst ? (Ointconst I16 Signed (repr ? off))), ?»
801      | Tunion _ _ ⇒ translate_addr vars e1
802      | _ ⇒ Error ? (msg BadlyTypedAccess)
803      ]
804  | _ ⇒ Error ? (msg BadLvalue)
805  ]
806].
807whd try @I
808[ >E whd @refl
809| 2,3: @pi2
810| @(translate_binop_vars … E) @pi2
811| % [ % ] @pi2
812| % [ % @pi2 ] whd @I
813| % [ % [ @pi2 | @I ] | @pi2 ]
814| % [ @pi2 | @I ]
815| % [ @pi2 | @I ]
816| @pi2
817| @pi2
818| % [ @pi2 | @I ]
819] qed.
820
821(* We provide a function to work out how to do an assignment to an lvalue
822   expression.  It is used for both Clight assignments and Clight function call
823   destinations, but doesn't take the value to be assigned so that we can use
824   it to form a single St_store when possible (and avoid introducing an
825   unnecessary temporary variable and assignment).
826   *)
827inductive destination (vars:var_types) : Type[0] ≝
828| IdDest : ∀id,ty. local_id vars id (typ_of_type ty) → destination vars
829| MemDest : (Σe:CMexpr ASTptr.expr_vars ? e (local_id vars)) → destination vars.
830
831(* Let a source Clight expression be assign(e1, e2). First of all, observe that [e1] is a
832  /Clight/ expression, not converted by translate_expr. We thus have to do part of the work
833  of [translate_expr] in this function. [translate_dest] will convert e1
834   into a proper destination for an assignement operation. We proceed by case analysis on e1.
835   - if e1 is a variable [id], then we proceed by case analysis on its allocation mode:
836      - if [id] is allocated locally (in a register), then id becomes directly
837        the target for the assignement, as (IdDest vars id t H), where t is the type
838        of id, and H asserts that id is indeed a local variable.
839      - if [id] is a global variable stored in region [r], then we perform [translate_expr]'s
840        job and return an adress, given as a constant symbol corresponding to [id], with
841        region r and memory chunk specified by the access mode of the rhs type ty2 of [e2].
842      - same thing for stack-allocated variables, except that we don't specify any region.
843   - if e1 is not a variable, we use [translate_addr] to generate a Cminor expression computing
844    the adres of e1
845*)
846definition translate_dest ≝
847λvars,e1.
848  match e1 with
849  [ Expr ed1 ty1 ⇒
850      match ed1 with
851      [ Evar id ⇒
852          do 〈c,t〉 as E ← lookup' vars id;
853          match c return λx.? → ? with
854          [ Local ⇒ λE. OK ? (IdDest vars id t ?)
855          | Global r ⇒ λE. OK ? (MemDest ? (Cst ? (Oaddrsymbol id 0)))
856          | Stack n ⇒ λE. OK ? (MemDest ? (Cst ? (Oaddrstack n)))
857          ] E
858      | _ ⇒
859          do e1' ← translate_addr vars e1;
860          OK ? (MemDest ? e1')
861      ]
862  ].
863whd // >E @refl
864qed.
865
866(* [lenv] is the type of maps from Clight labels to Cminor labels. *)
867definition lenv ≝ identifier_map SymbolTag (identifier Label).
868
869axiom MissingLabel : String.
870
871(* Find the Cminor label corresponding to [l] or fail. *)
872definition lookup_label ≝
873λlbls:lenv.λl. opt_to_res … [MSG MissingLabel; CTX ? l] (lookup ?? lbls l).
874
875(* True iff the Cminor label [l] is in the codomain of [lbls] *)
876definition lpresent ≝ λlbls:lenv. λl. ∃l'. lookup_label lbls l' = OK ? l.
877
878(* True iff The Clight label [l] is in the domain of [lbls] *)
879definition label_in_domain ≝ λlbls:lenv. λl. present ?? lbls l.
880
881let rec fresh_list_for_univ (l:list (identifier Label)) (u:universe Label) ≝
882match l with
883[ nil ⇒ True
884| cons elt tl ⇒ fresh_for_univ ? elt u ∧ fresh_list_for_univ tl u].
885
886record labgen : Type[0] ≝ {
887  labuniverse   : universe Label;
888  label_genlist    : list (identifier Label);
889  genlist_is_fresh : fresh_list_for_univ label_genlist labuniverse
890}.
891
892lemma fresh_list_stays_fresh : ∀l,tmp,u,u'. fresh_list_for_univ l u → 〈tmp,u'〉=fresh Label u → fresh_list_for_univ l u'.
893#l elim l
894[ 1: normalize //
895| 2: #hd #tl #Hind #tmp #u #u' #HA #HB
896  whd
897  @conj
898  [ 1: whd in HA ⊢ ?;
899    elim HA #HAleft #HAright
900    @(fresh_remains_fresh ? hd tmp u u') assumption
901  | 2: whd in HA ⊢ ?;
902    elim HA #HAleft #HAright   
903    @Hind //
904  ]
905]
906qed.
907
908definition In ≝ λelttype.λelt.λl.Exists elttype (λx.x=elt) l.   
909
910definition generate_fresh_label :
911 ∀ul. Σlul:(identifier Label × labgen).
912               (And (∀lab. In ? lab (label_genlist ul) → In ? lab (label_genlist (snd … lul)))
913                   (In ? (fst … lul) (label_genlist (snd … lul)))) ≝
914λul.
915let 〈tmp,u〉 as E ≝ fresh ? (labuniverse ul) in
916 «〈tmp, mk_labgen u (tmp::(label_genlist ul)) ?〉, ?».
917[ 1: normalize @conj
918  [ 1: @(fresh_is_fresh ? tmp u (labuniverse ul) ?) assumption
919  | 2: @fresh_list_stays_fresh // ]
920| @conj /2/
921]
922qed.
923
924let rec labels_defined (s:statement) : list ident ≝
925match s with
926[ Ssequence s1 s2 ⇒ labels_defined s1 @ labels_defined s2
927| Sifthenelse _ s1 s2 ⇒ labels_defined s1 @ labels_defined s2
928| Swhile _ s ⇒ labels_defined s
929| Sdowhile _ s ⇒ labels_defined s
930| Sfor s1 _ s2 s3 ⇒ labels_defined s1 @ labels_defined s2 @ labels_defined s3
931| Sswitch _ ls ⇒ labels_defined_switch ls
932| Slabel l s ⇒ l::(labels_defined s)
933| Scost _ s ⇒ labels_defined s
934| _ ⇒ [ ]
935]
936and labels_defined_switch (ls:labeled_statements) : list ident ≝
937match ls with
938[ LSdefault s ⇒ labels_defined s
939| LScase _ _ s ls ⇒ labels_defined s @ labels_defined_switch ls
940].
941
942definition ldefined ≝ λs.λl.Exists ? (λl'.l' = l) (labels_of s).
943
944(* For each label l in s, there exists a matching label l' = lenv(l) defined in s' *)
945definition labels_translated : lenv → statement → stmt → Prop ≝
946λlbls,s,s'.  ∀l.
947  (Exists ? (λl'.l' = l) (labels_defined s)) →
948  ∃l'. lookup_label lbls l = (OK ? l') ∧ ldefined s' l'.
949
950
951(* Invariant on statements, holds during conversion to Cminor *)
952definition stmt_inv ≝  λvars. stmt_P (stmt_vars (local_id vars)).
953
954(* I (Ilias) decided to inline the following definition, to make explicit the data constructed.
955 * This was needed to prove some stuff in translate_statement at some point, but it might be
956 * useless now. If needed, I can revert this change.  *)
957definition translate_assign : ∀vars:var_types. expr → expr → res (Σs:stmt. stmt_inv vars s) ≝
958λvars,e1,e2.
959do e2' ← translate_expr vars e2;
960do dest ← translate_dest vars e1;
961match dest with
962[ IdDest id ty p ⇒
963    do e2' ← type_should_eq (typeof e2) ty ? e2';
964    OK ? «St_assign ? id e2', ?»
965| MemDest e1' ⇒ OK ? «St_store ? e1' e2', ?»
966].
967% try (//) elim e2' /2/ elim e1' /2/
968qed.
969
970definition m_option_map : ∀A,B:Type[0]. (A → res B) → option A → res (option B) ≝
971λA,B,f,oa.
972match oa with
973[ None ⇒ OK ? (None ?)
974| Some a ⇒ do b ← f a; OK ? (Some ? b)
975].
976
977definition translate_expr_sigma : ∀vars:var_types. expr → res (Σe:(𝚺t:typ.CMexpr t). match e with [ mk_DPair t e ⇒ expr_vars t e (local_id vars) ]) ≝
978λv,e.
979  do e' ← translate_expr v e;
980  OK (Σe:(𝚺t:typ.CMexpr t).?) «❬?, e'❭, ?».
981whd @pi2
982qed.
983
984(* Add the list of typed variables tmpenv to the environment [var_types] with
985   the allocation mode Local. *)
986definition add_tmps : var_types → list (ident × type) → var_types ≝
987λvs,tmpenv.
988  foldr ?? (λidty,vs. add ?? vs (\fst idty) 〈Local, \snd idty〉) vs tmpenv.
989
990record tmpgen (vars:var_types) : Type[0] ≝ {
991  tmp_universe : universe SymbolTag;
992  tmp_env : list (ident × type);
993  tmp_ok : fresh_map_for_univ … (add_tmps vars tmp_env) tmp_universe;
994  tmp_preserved :
995    ∀id,ty. local_id vars id ty → local_id (add_tmps vars tmp_env) id ty
996}.
997
998definition alloc_tmp : ∀vars. type → tmpgen vars → ident × (tmpgen vars) ≝
999λvars,ty,g.
1000  let 〈tmp,u〉 as E ≝ fresh ? (tmp_universe ? g) in
1001  〈tmp, mk_tmpgen ? u (〈tmp, ty〉::(tmp_env ? g)) ??〉.
1002[ #id #ty'
1003  whd in ⊢ (? → ?%??);
1004  whd in ⊢ (% → %);
1005  whd in ⊢ (? → match % with [_ ⇒ ? | _ ⇒ ?]); #H
1006  >lookup_add_miss
1007  [ @(tmp_preserved … g) @H
1008  | @(fresh_distinct … E) @(tmp_ok … g)
1009    lapply (tmp_preserved … g id ty' H)
1010    whd in ⊢ (% → %);
1011    whd in ⊢ (match % with [_ ⇒ ? | _ ⇒ ?] → ?);
1012    cases (lookup ??? id)
1013    [ * | #x #_ % #E destruct ]
1014  ]
1015| @fresh_map_add
1016  [ @(fresh_map_preserved … E) @(tmp_ok … g)
1017  | @(fresh_is_fresh … E)
1018  ]
1019] qed.
1020
1021
1022lemma lookup_label_hit : ∀lbls,l,l'.
1023  lookup_label lbls l = OK ? l' →
1024  lpresent lbls l'.
1025#lbls #l #l' #E whd %{l} @E
1026qed.
1027
1028(* TODO: is this really needed now? *)
1029
1030definition tmps_preserved : ∀vars:var_types. tmpgen vars → tmpgen vars → Prop ≝
1031λvars,u1,u2.
1032  ∀id,ty. local_id (add_tmps vars (tmp_env … u1)) id ty → local_id (add_tmps vars (tmp_env … u2)) id ty.
1033
1034lemma alloc_tmp_preserves : ∀vars,tmp,u,u',q.
1035  〈tmp,u'〉 = alloc_tmp ? q u → tmps_preserved vars u u'.
1036#vars #tmp * #u1 #e1 #F1 #P1 * #u2 #e2 #F2 #P2 #q
1037whd in ⊢ (???% → ?); generalize in ⊢ (???(?%) → ?);
1038cases (fresh SymbolTag u1) in ⊢ (??%? → ???(match % with [ _ ⇒ ? ]?) → ?);
1039#tmp' #u' #E1 #E2 whd in E2:(???%); destruct
1040#id #ty #H whd in ⊢ (?%??); whd in H ⊢ %;
1041whd in ⊢ match % with [ _ ⇒ ? | _ ⇒ ? ];
1042>lookup_add_miss // @(fresh_distinct … E1) @F1
1043whd in H:(match % with [_ ⇒ ?|_ ⇒ ?]) ⊢ %;
1044cases (lookup ??? id) in H ⊢ %;
1045[ * | #x #_ % #E destruct ]
1046qed.
1047
1048lemma add_tmps_oblivious : ∀vars,s,u.
1049  stmt_inv vars s → stmt_inv (add_tmps vars (tmp_env vars u)) s.
1050#vars #s #u #H
1051@(stmt_P_mp … H)
1052#s' #H1 @(stmt_vars_mp … H1) #id #t #H @(tmp_preserved ? u ?? H)
1053qed.
1054
1055lemma local_id_fresh_tmp : ∀vars,tmp,u,ty,u0.
1056  〈tmp,u〉 = alloc_tmp vars ty u0 → local_id (add_tmps vars (tmp_env … u)) tmp (typ_of_type ty).
1057#vars #tmp #u #ty #u0
1058whd in ⊢ (???% → ?); generalize in ⊢ (???(?%) → ?);
1059cases (fresh SymbolTag (tmp_universe vars u0)) in ⊢ (??%? → ???(match % with [_⇒?]?) → ?);
1060* #tmp' #u' #e #E whd in E:(???%);
1061destruct
1062whd in ⊢ (?%??); whd whd in ⊢ match % with [ _ ⇒ ? | _ ⇒ ? ]; >lookup_add_hit
1063@refl
1064qed.
1065
1066
1067let rec mklabels (ul:labgen) : (identifier Label) × (identifier Label) × labgen ≝
1068  match generate_fresh_label ul with
1069  [ mk_Sig res1 H1 ⇒
1070     let 〈entry_label, ul1〉 as E1 ≝ res1 in
1071     match generate_fresh_label ul1 with
1072     [ mk_Sig res2 H2 ⇒
1073        let 〈exit_label, ul2〉 as E2 ≝ res2 in
1074        〈entry_label, exit_label, ul2〉
1075     ]
1076  ].
1077
1078(* When converting loops into gotos, and in order to eliminate blocks, we have
1079 * to convert continues and breaks into goto's, too. We add some "flags" in
1080 * in argument to [translate_statement], meaning that the next encountered break
1081 * or continue has to be converted into a goto to some contained label.
1082 * ConvertTo l1 l2 means "convert continue to goto l1 and convert break to goto l2".
1083 *)
1084inductive convert_flag : Type[0] ≝
1085| DoNotConvert : convert_flag
1086| ConvertTo    : identifier Label → identifier Label → convert_flag. (* continue, break *)
1087
1088let rec labels_of_flag (flag : convert_flag) : list (identifier Label) ≝
1089match flag with
1090[ DoNotConvert ⇒ [ ]
1091| ConvertTo continue break ⇒ continue :: break :: [ ]
1092].
1093
1094(* For a top-level expression, [label-wf] collapses to "all labels are properly declared" *)
1095definition label_wf ≝
1096λ (s : statement) .λ (s' : stmt) .λ (lbls : lenv). λ (flag : convert_flag).
1097    stmt_P (λs1. stmt_labels (λl.ldefined s' l ∨ lpresent lbls l ∨ In ? l (labels_of_flag flag)) s1) s'.
1098
1099definition return_ok : option typ → stmt → Prop ≝
1100λot.
1101stmt_P (λs.
1102  match s with [ St_return oe ⇒
1103    match oe with [ Some e ⇒ Some ? (dpi1 … e) = ot | None ⇒ None ? = ot ]
1104  | _ ⇒ True ]).
1105
1106(* trans_inv is the invariant which is enforced during the translation from Clight to Cminor.
1107  The involved arguments are the following:
1108  . vars:var_types, an environment mapping variables to their types and allocation modes
1109  . lbls:lenv, a mapping from old (Clight) to fresh and new (Cminor) labels,
1110  . s:statement, a Clight statement,
1111  . uv, a fresh variable generator (containing itself some invariants)
1112  . flag, wich maps "break" and "continue" to "gotos"
1113  . su', a couple of a Cminor statement and fresh variable generator.
1114*)
1115definition trans_inv : ∀vars:var_types . ∀lbls:lenv . statement → tmpgen vars → convert_flag → option typ → ((tmpgen vars) × labgen × stmt) → Prop ≝
1116λvars,lbls,s,uv,flag,rettyp,su'.
1117  let 〈uv', ul', s'〉 ≝ su' in
1118  stmt_inv (add_tmps vars (tmp_env … uv')) s' ∧   (* remaining variables in s' are local*)
1119  labels_translated lbls s s' ∧                   (* all the labels in s are transformed in label of s' using [lbls] as a map *)
1120  tmps_preserved vars uv uv' ∧                    (* the variables generated are local and grows in a monotonic fashion *)
1121  return_ok rettyp s' ∧                           (* return statements have correct typ *)
1122  label_wf s s' lbls flag.                        (* labels are "properly" declared, as defined in [ŀabel_wf].*)
1123
1124axiom ReturnMismatch : String.
1125
1126let rec translate_statement (vars:var_types) (uv:tmpgen vars) (ul:labgen) (lbls:lenv) (flag:convert_flag) (rettyp:option typ) (s:statement) on s
1127  : res (Σsu:(tmpgen vars)×labgen×stmt.trans_inv vars lbls s uv flag rettyp su) ≝
1128match s return λs.res (Σsu:(tmpgen vars)×labgen×stmt.trans_inv vars lbls s uv flag rettyp su) with
1129[ Sskip ⇒ OK ? «〈uv, ul, St_skip〉, ?»
1130| Sassign e1 e2 ⇒
1131    do e2' ← translate_expr vars e2;  (* rhs *)
1132    do dest ← translate_dest vars e1; (* e1 *)
1133    match dest with
1134    [ IdDest id ty p ⇒
1135       do e2' ← type_should_eq (typeof e2) ty ? e2';
1136       OK ? «〈uv, ul, St_assign ? id e2'〉, ?»
1137    | MemDest e1' ⇒
1138       OK ? «〈uv, ul, St_store ? e1' e2'〉, ?»
1139    ]
1140| Scall ret ef args ⇒
1141    do ef' ← translate_expr vars ef;
1142    do ef' ← typ_should_eq (typ_of_type (typeof ef)) ASTptr ? ef';
1143    do args' ← mmap_sigma ??? (translate_expr_sigma vars) args;
1144    match ret with
1145    [ None ⇒ OK ? «〈uv, ul, St_call (None ?) ef' args'〉, ?»
1146    | Some e1 ⇒
1147        do dest ← translate_dest vars e1;
1148        match dest with
1149        [ IdDest id ty p ⇒ OK ? «〈uv, ul, St_call (Some ? 〈id,typ_of_type ty〉) ef' args'〉, ?»
1150        | MemDest e1' ⇒
1151            let 〈tmp, uv1〉 as Etmp ≝ alloc_tmp ? (typeof e1) uv in
1152            OK ? «〈uv1, ul, St_seq (St_call (Some ? 〈tmp,typ_of_type (typeof e1)〉) ef' args') (St_store (typ_of_type (typeof e1)) e1' (Id ? tmp))〉, ?»
1153        ]
1154    ]
1155| Ssequence s1 s2 ⇒
1156    do «fgens1, s1', H1» ← translate_statement vars uv ul lbls flag rettyp s1;
1157    do «fgens2, s2', H2» ← translate_statement vars (fst … fgens1) (snd … fgens1) lbls flag rettyp s2;
1158    OK ? «〈fgens2, St_seq s1' s2'〉, ?»
1159| Sifthenelse e1 s1 s2 ⇒
1160    do e1' ← translate_expr vars e1;
1161    match typ_of_type (typeof e1) return λx.(Σe:CMexpr x.expr_vars ? e ?) → ? with
1162    [ ASTint _ _ ⇒ λe1'.
1163         do «fgens1, s1', H1» ← translate_statement vars uv ul lbls flag rettyp s1;
1164         do «fgens2, s2', H2» ← translate_statement vars (fst … fgens1) (snd … fgens1) lbls flag rettyp s2;
1165        OK ? «〈fgens2, St_ifthenelse ?? e1' s1' s2'〉, ?»
1166    | _ ⇒ λ_.Error ? (msg TypeMismatch)
1167    ] e1'
1168(* Performing loop conversions while keeping good cost labelling properties is
1169   a little tricky.  In principle we should have a cost label in each branch,
1170   but the behaviour of the next stage means that we can put in Cminor skips and
1171   goto labels before the cost label. *)
1172| Swhile e1 s1 ⇒
1173    do e1' ← translate_expr vars e1;
1174    match typ_of_type (typeof e1) return λx.(Σe:CMexpr x.expr_vars ? e ?) → ? with
1175    [ ASTint _ _ ⇒ λe1'.         
1176        let 〈labels, ul1〉 as E1 ≝ mklabels ul in
1177        let 〈entry, exit〉 as E2 ≝ labels in
1178        do «fgens2, s1',H1» ← translate_statement vars uv ul1 lbls (ConvertTo entry exit) rettyp s1;
1179        let converted_loop ≝
1180          St_label entry
1181          (St_seq
1182            (St_ifthenelse ?? e1' (St_seq s1' (St_goto entry)) St_skip)
1183            (St_label exit St_skip))
1184        in         
1185          OK ? «〈fgens2, converted_loop〉, ?»
1186    | _ ⇒ λ_.Error ? (msg TypeMismatch)
1187    ] e1'
1188| Sdowhile e1 s1 ⇒
1189    do e1' ← translate_expr vars e1;
1190    match typ_of_type (typeof e1) return λx.(Σe:CMexpr x. expr_vars ? e ?) → ? with
1191    [ ASTint _ _ ⇒ λe1'.
1192        let 〈labels, ul1〉 as E1 ≝ mklabels ul in
1193        let 〈condexpr, exit〉 as E2 ≝ labels in
1194        let 〈body, ul2〉 ≝ generate_fresh_label … ul1 in
1195        do «fgens2, s1', H1» ← translate_statement vars uv ul2 lbls (ConvertTo condexpr exit) rettyp s1;
1196        (* This is particularly carefully implemented, we need to reach the
1197           cost label in s1' or the cost label after the loop (if they are
1198           present) after the ifthenelse, and we're only allowed skips and
1199           goto labels in between.  So we structure it like a while with a goto
1200           into the middle (the CFG will be essentially the same, anyway.) *)
1201        let converted_loop ≝
1202        St_seq
1203          (St_seq
1204            (St_goto body)
1205            (St_label condexpr
1206              (St_ifthenelse ?? e1'
1207                (St_label body
1208                  (St_seq
1209                    s1'
1210                    (St_goto condexpr)))
1211                St_skip)))
1212          (St_label exit St_skip)
1213        in
1214        OK ? «〈fgens2, converted_loop〉, ?»
1215    | _ ⇒ λ_.Error ? (msg TypeMismatch)
1216    ] e1'
1217| Sfor s1 e1 s2 s3 ⇒
1218    do e1' ← translate_expr vars e1;
1219    match typ_of_type (typeof e1) return λx.(Σe:CMexpr x. expr_vars ? e ?) → ? with
1220    [ ASTint _ _ ⇒ λe1'.
1221        let 〈labels, ul1〉 as E ≝ mklabels ul in
1222        let 〈continue, exit〉 as E2 ≝ labels in
1223        let 〈entry, ul2〉 ≝ generate_fresh_label … ul1 in
1224        do «fgens2, s1', H1» ← translate_statement vars uv ul2 lbls flag rettyp s1;
1225        (* The choice of flag is arbitrary - Clight's semantics give no meaning
1226           to continue or break in s2 because in C it must be an expression. *)
1227        do «fgens3, s2', H2» ← translate_statement vars (fst … fgens2) (snd … fgens2) lbls flag rettyp s2;
1228        do «fgens4, s3', H3» ← translate_statement vars (fst … fgens3) (snd … fgens3) lbls (ConvertTo continue exit) rettyp s3;
1229        let converted_loop ≝
1230          St_seq
1231            s1'
1232            (St_label entry
1233              (St_seq
1234                (St_ifthenelse ?? e1' (St_seq s3' (St_label continue (St_seq s2' (St_goto entry)))) St_skip)
1235                (St_label exit St_skip)
1236            ))
1237        in
1238          OK ? «〈fgens4, converted_loop〉, ?»
1239    | _ ⇒ λ_.Error ? (msg TypeMismatch)
1240    ] e1'
1241| Sbreak ⇒
1242   match flag return λf.flag = f → ? with
1243   [ DoNotConvert ⇒ λEflag.
1244     Error ? (msg FIXME)
1245   | ConvertTo continue_label break_label ⇒ λEflag.
1246     OK ? «〈uv, ul, St_goto break_label〉, ?»
1247   ] (refl ? flag)
1248| Scontinue ⇒
1249  match flag return λf.flag = f → ? with
1250  [ DoNotConvert ⇒ λEflag.
1251    Error ? (msg FIXME)
1252  | ConvertTo continue_label break_label ⇒ λEflag.
1253    OK ? «〈uv, ul, St_goto continue_label〉, ?»
1254  ] (refl ? flag)
1255| Sreturn ret ⇒
1256    match ret with
1257    [ None ⇒
1258        match rettyp return λx.res (Σy.trans_inv … x y) with
1259        [ None ⇒ OK ? «〈uv, ul, St_return (None ?)〉, ?»
1260        | _ ⇒ Error ? (msg ReturnMismatch)
1261        ]
1262    | Some e1 ⇒
1263        match rettyp return λx.res (Σy.trans_inv … x y) with
1264        [ Some rty ⇒
1265            do e1' ← translate_expr vars e1;
1266            do e1' ← typ_should_eq (typ_of_type (typeof e1)) rty ? e1';
1267            OK ? «〈uv, ul, St_return (Some ? (mk_DPair … e1'))〉, ?»
1268        | _ ⇒ Error ? (msg ReturnMismatch)
1269        ]
1270    ]
1271| Sswitch e1 ls ⇒ Error ? (msg FIXME)
1272| Slabel l s1 ⇒
1273    do l' as E ← lookup_label lbls l;
1274    do «fgens1, s1', H1» ← translate_statement vars uv ul lbls flag rettyp s1;
1275    OK ? «〈fgens1, St_label l' s1'〉, ?»
1276| Sgoto l ⇒
1277    do l' as E ← lookup_label lbls l;
1278    OK ? «〈uv, ul, St_goto l'〉, ?»
1279| Scost l s1 ⇒
1280    do «fgens1, s1', H1» ← translate_statement vars uv ul lbls flag rettyp s1;
1281    OK ? «〈fgens1, St_cost l s1'〉, ?»
1282].
1283try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj
1284try (@I)
1285try (#l #H elim H)
1286try (#size #sign #H assumption)
1287try (#H1 try #H2 assumption)
1288[ 1,5: @(tmp_preserved … p) ]
1289[ 1,3: elim e2' | 2,9,24: elim e1' | 4,7,14: elim ef' ]
1290[ 1,2,3,4,5,6,7,8 : #e #Hvars @(expr_vars_mp … Hvars) #i #t #Hlocal @(tmp_preserved … Hlocal) ]
1291[ 1: @All_mp [ 1: @(λe.match e with [ mk_DPair t e0 ⇒ expr_vars t e0 (local_id vars) ])
1292             | 2: * #t #e #Hev whd in Hev ⊢ %; @(expr_vars_mp … Hev) #i #t #Hp @(tmp_preserved … Hp)
1293             | 3: elim args' // ]
1294| 8: (* we should be able to merge this case with the previous ... *)
1295     @All_mp [ 1: @(λe.match e with [ mk_DPair t e0 ⇒ expr_vars t e0 (local_id vars) ])
1296             | 2: * #t #e #Hev whd in Hev ⊢ %; @(expr_vars_mp … Hev) #i #t #Hp @(tmp_preserved … Hp)
1297             | 3: elim args' // ]
1298| 2: @(local_id_fresh_tmp vars tmp uv1 (typeof e1) uv Etmp)
1299| 3:  @(All_mp (𝚺 t:typ.expr t) (λe. match e with [ mk_DPair t e0 ⇒ expr_vars t e0 (local_id vars)]))
1300       [ 1: #a #Ha elim a in Ha ⊢ ?; #ta #a #Ha whd @(expr_vars_mp ?? (local_id vars))
1301       [ 1: #i0 #t0 #H0 @(tmp_preserved vars uv1 i0 t0 H0)
1302       | 2: assumption ]
1303       | 2: elim args' // ]
1304| 4: @(local_id_fresh_tmp vars tmp uv1 (typeof e1) uv Etmp) ]
1305[ 1: #size #sign | 2: | 3: #fsize ]
1306[ 1,2,3: #H @(alloc_tmp_preserves vars tmp uv uv1 … Etmp) @H ]
1307try @refl (* Does (at least) the return_ok cases *)
1308try @(match fgens1 return λx.x=fgens1 → ? with
1309     [ mk_Prod uv1 ul1 ⇒ λHfgens1.? ] (refl ? fgens1))
1310try @(match fgens2 return λx.x=fgens2 → ? with
1311     [ mk_Prod uv2 ul2 ⇒ λHfgens2.? ] (refl ? fgens2))
1312try @(match fgens3 return λx.x=fgens3 → ? with
1313     [ mk_Prod uv3 ul3 ⇒ λHfgens3.? ] (refl ? fgens3))
1314try @(match fgens4 return λx.x=fgens4 → ? with
1315     [ mk_Prod uv4 ul4 ⇒ λHfgens4.? ] (refl ? fgens4))
1316whd in H1 H2 H3 ⊢ ?; destruct whd nodelta in H1 H2 H3;
1317try (elim H1 -H1 * * * #Hstmt_inv1 #Hlabels_tr1 #Htmps_pres1 #Hret1)
1318try (elim H2 -H2 * * * #Hstmt_inv2 #Hlabels_tr2 #Htmps_pres2 #Hret2)
1319try (elim H3 -H3 * * * #Hstmt_inv3 #Hlabels_tr3 #Htmps_pres3 #Hret3)
1320[ 1,2: #Hind1 #Hind2 | 3,4,8,10: #Hind | 5: #Hind1 #Hind2 #Hind3 ]
1321try @conj try @conj try @conj try @conj try @conj try @conj try (whd @I) try assumption
1322[ 1,7: @(stmt_P_mp … Hstmt_inv1) #e #Hvars @(stmt_vars_mp … Hvars) #i #t #Hlocal @(Htmps_pres2 … Hlocal)
1323| 2: #l #H cases (Exists_append ???? H) #Hcase
1324         [ 1: elim (Hlabels_tr1 l Hcase) #label #Hlabel @(ex_intro … label) @conj
1325           [ 1: @(proj1 ?? Hlabel)
1326           | 2: normalize @Exists_append_l @(proj2 … Hlabel) ]
1327         | 2: elim (Hlabels_tr2 l Hcase) #label #Hlabel @(ex_intro … label) @conj
1328           [ 1: @(proj1 ?? Hlabel)
1329           | 2: normalize @Exists_append_r @(proj2 … Hlabel) ]
1330         ]
1331| 3,9: #id #ty #H @(Htmps_pres2 … (Htmps_pres1 id ty H)) ]
1332[ 1: @(stmt_P_mp … Hind2) | 2: @(stmt_P_mp … Hind1) ]
1333[ 1,2: #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1334     #l * try * [ 1,4: #H %1 %1 normalize in H ⊢ %; try (@Exists_append_l @H); try (@Exists_append_r @H)
1335                | 2,5: #H %1 %2 assumption
1336                | 3,6: #H %2 assumption ]
1337(* if/then/else *)
1338| 3: whd elim e1' #e #Hvars @(expr_vars_mp … Hvars) #i #t #Hlocal @(tmp_preserved … Hlocal)
1339| 4: whd #l #H
1340       cases (Exists_append ???? H) #Hcase
1341         [ 1: elim (Hlabels_tr1 l Hcase) #label #Hlabel @(ex_intro … label) @conj
1342           [ 1: @(proj1 ?? Hlabel)
1343           | 2: normalize @Exists_append_l @(proj2 … Hlabel) ]
1344         | 2: elim (Hlabels_tr2 l Hcase) #label #Hlabel @(ex_intro … label) @conj
1345           [ 1: @(proj1 ?? Hlabel)
1346           | 2: normalize @Exists_append_r @(proj2 … Hlabel) ]
1347         ]
1348]                 
1349[ 1: 1: @(stmt_P_mp … Hind2) | 2: @(stmt_P_mp … Hind1) ]
1350[ 1,2: #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1351     #l * try * [ 1,4: #H %1 %1 normalize in H ⊢ %; try (@Exists_append_l @H); try (@Exists_append_r @H)
1352                | 2,5: #H %1 %2 assumption
1353                | 3,6: #H %2 assumption ] ]
1354try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @I try assumption
1355[ 1,7,19: whd elim e1' #e #Hvars @(expr_vars_mp … Hvars) #i #t #Hlocal @(tmp_preserved … Hlocal)
1356| 2,8: whd #l #H normalize in H;
1357       elim (Hlabels_tr1 … H) #label #Hlabel @(ex_intro … label)
1358       @conj
1359       [ 1,3: @(proj1 … Hlabel)
1360       | 2,4: whd @or_intror normalize in ⊢ (???%);
1361              [ @Exists_append_l @Exists_append_l @Exists_append_l | %2 @Exists_append_l @Exists_append_l @Exists_append_l ]
1362              @(proj2 … Hlabel) ]
1363| whd %1 %1 normalize /2/
1364| 4,12: @(stmt_P_mp … Hind) #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1365   #l * try * [ 1,5: #H %1 %1 normalize %2 [ 2: %2 ] @Exists_append_l @Exists_append_l try @Exists_append_l @H
1366              | 2,6: #H %1 %2 assumption
1367              | 3,7: #H <H %1 %1 normalize /2/
1368              | 4,8: #H normalize in H; elim H [ 1,3: #E <E %1 %1 normalize %2 [2: %2]
1369                                                 @Exists_append_r normalize /2/
1370                                               | 2,4: * ]
1371              ]
1372| normalize %1 %1 %1 //
1373| 6,11: normalize %1 %1 %2 [ @Exists_append_r normalize /2/ | %1 % ]
1374| whd %1 %1 normalize %2 %1 %
1375| 10,13: normalize %1 %1 %1 %
1376| normalize %1 %1 %2 %2 /2/
1377| whd #label * [ 1: #Eq @(ex_intro … l') @conj [ 1: destruct // | whd /2/ ]
1378               | 2: #H elim (Hlabels_tr1 label H)
1379                    #lab * #Hlookup #Hdef @(ex_intro … lab) @conj
1380                    [ 1: // | 2: whd %2 assumption ]
1381               ]
1382| normalize %1 %1 %1 %
1383| @(stmt_P_mp … Hind) #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1384  #l * try * [ 1: #H %1 %1 normalize %2 @H
1385             | 2: #H %1 %2 assumption
1386             | 3: #H %2 assumption ]
1387| @(stmt_P_mp … Hstmt_inv1) #s0 #Hstmt_vars @(stmt_vars_mp … Hstmt_vars) #i #t
1388  #H @(Htmps_pres3 … (Htmps_pres2 … H))
1389| @(stmt_P_mp … Hstmt_inv2) #s0 #Hstmt_vars @(stmt_vars_mp … Hstmt_vars) #i #t
1390  #H @(Htmps_pres3 … H)
1391| % //
1392| whd #l #H normalize in H;
1393  cases (Exists_append … H) #Hcase
1394  [ 1: elim (Hlabels_tr1 l Hcase) #label #Hlabel @(ex_intro … label) @conj
1395    [ 1: @(proj1 … Hlabel)
1396    | 2: normalize @Exists_append_l @(proj2 … Hlabel)
1397    ]
1398  | 2: cases (Exists_append … Hcase) #Hcase2
1399    [ 1: elim (Hlabels_tr2 l Hcase2) #label #Hlabel @(ex_intro … label) @conj
1400      [ 1: @(proj1 … Hlabel)
1401      | 2: normalize >append_nil >append_nil >append_cons
1402           @Exists_append_r @Exists_append_l @Exists_append_r %2
1403           @(proj2 … Hlabel)
1404      ]
1405    | 2: elim (Hlabels_tr3 l Hcase2) #label #Hlabel @(ex_intro … label) @conj
1406      [ 1: @(proj1 … Hlabel)
1407      | 2: normalize >append_nil >append_nil >append_cons
1408         @Exists_append_r @Exists_append_l @Exists_append_l
1409         @(proj2 … Hlabel)
1410      ]
1411    ]
1412  ]
1413| #id #ty #H @(Htmps_pres3 … (Htmps_pres2 … (Htmps_pres1 … H)))
1414| @(stmt_P_mp … Hind3) #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1415   #l * try * [ 1: #H %1 %1 normalize @Exists_append_l @H
1416              | 2: #H %1 %2 assumption
1417              | 3: #H %2 assumption ]
1418| whd %1 %1 normalize /2/
1419| @(stmt_P_mp … Hind1) #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1420   #l * try * [ 1: #H %1 %1 normalize @Exists_append_r @(Exists_add ?? (nil ?))
1421                   @Exists_append_r @Exists_append_l @Exists_append_l
1422                   @Exists_append_l assumption
1423              | 2: #H %1 %2 assumption
1424              | 3: #H <H %1 %1 normalize
1425                   @Exists_append_r %2 @Exists_append_l @Exists_append_l
1426                   @Exists_append_r %1 %
1427              | 4: * [ 1: #Eq <Eq %1 %1 whd normalize
1428                       @Exists_append_r @(Exists_add ?? (nil ?)) @Exists_append_r
1429                       @Exists_append_r whd %1 //
1430                     | 2: * ]
1431              ]
1432| % %1 normalize @Exists_append_r %2 @Exists_append_l @Exists_append_l
1433  @Exists_append_r % %
1434| @(stmt_P_mp … Hind2) #s0 #Hstmt_labels @(stmt_labels_mp … Hstmt_labels)
1435   #l * try * [ 1: #H %1 %1 normalize @Exists_append_r @(Exists_add ?? (nil ?))
1436                   @Exists_append_r @Exists_append_l @Exists_append_l                   
1437                   @Exists_append_r %2 @Exists_append_l assumption
1438              | 2: #H %1 %2 assumption
1439              | 3: /2/
1440              ]
1441| whd %1 %1 normalize /2/
1442| whd %1 %1 normalize
1443  @Exists_append_r @(Exists_add ?? (nil ?)) @Exists_append_r @Exists_append_r
1444  whd %1 //
1445| normalize %2 /3/
1446| normalize /4/
1447| whd %1 %2 whd @(ex_intro … l) @E
1448] qed.
1449
1450axiom ParamGlobalMixup : String.
1451
1452(* params and statement aren't real parameters, they're just there for giving the invariant. *)
1453definition alloc_params :
1454 ∀vars:var_types.∀lbls,statement,uv,flag,rettyp. list (ident×type) → (Σsu:(tmpgen vars)×labgen×stmt. trans_inv vars lbls statement uv flag rettyp su)
1455   → res (Σsu:(tmpgen vars)×labgen×stmt.trans_inv vars lbls statement uv flag rettyp su) ≝   
1456λvars,lbls,statement,uv,ul,rettyp,params,s. foldl ?? (λsu,it.
1457  let 〈id,ty〉 ≝ it in
1458  do «result,Is» ← su;
1459  let 〈fgens1, s〉 as Eresult ≝ result in
1460  do 〈t,ty'〉 as E ← lookup' vars id;
1461  match t return λx.? → res (Σsu:(tmpgen vars)×labgen×stmt.trans_inv vars lbls statement uv ul rettyp su) with
1462  [ Local ⇒ λE. OK (Σs:(tmpgen vars)×labgen×stmt.?) «result,Is»
1463  | Stack n ⇒ λE.
1464      OK ? «〈fgens1, St_seq (St_store ? (Cst ? (Oaddrstack n)) (Id (typ_of_type ty') id)) s〉, ?»
1465  | Global _ ⇒ λE. Error ? [MSG ParamGlobalMixup; CTX ? id]
1466  ] E) (OK ? s) params.
1467whd
1468@(match fgens1 return λx.x=fgens1 → ? with
1469  [ mk_Prod uv1 ul1 ⇒ λHfgens1.? ] (refl ? fgens1))
1470whd in Is ⊢ %; destruct whd in Is;
1471try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @conj try @I
1472elim Is * * * #Hincl #Hstmt_inv #Hlab_tr #Hret #Htmp_pr try assumption
1473@(expr_vars_mp … (tmp_preserved … uv1)) whd >E @refl
1474qed.
1475
1476axiom DuplicateLabel : String.
1477
1478definition lenv_list_inv : lenv → lenv → list ident → Prop ≝
1479λlbls0,lbls,ls.
1480 ∀l,l'. lookup_label lbls l = OK ? l' →
1481 Exists ? (λl'. l' = l) ls ∨ lookup_label lbls0 l = OK ? l'.
1482
1483lemma lookup_label_add : ∀lbls,l,l'.
1484  lookup_label (add … lbls l l') l = OK ? l'.
1485#lbls #l #l' whd in ⊢ (??%?); >lookup_add_hit @refl
1486qed.
1487
1488lemma lookup_label_miss : ∀lbls,l,l',l0.
1489  l0 ≠ l →
1490  lookup_label (add … lbls l l') l0 = lookup_label lbls l0.
1491#lbls #l #l' #l0 #NE
1492whd in ⊢ (??%%);
1493>lookup_add_miss
1494[ @refl | @NE ]
1495qed.
1496
1497let rec populate_lenv (ls:list ident) (ul:labgen) (lbls:lenv): res ((Σlbls':lenv. lenv_list_inv lbls lbls' ls) × labgen) ≝
1498match ls return λls.res ((Σlbls':lenv. lenv_list_inv lbls lbls' ls) × labgen) with
1499[ nil ⇒ OK ? 〈«lbls, ?», ul〉
1500| cons l t ⇒
1501  match lookup_label lbls l return λlook. lookup_label lbls l = look → ? with
1502  [ OK _    ⇒ λ_.Error ? (msg DuplicateLabel)
1503  | Error _ ⇒ λLOOK.
1504    match generate_fresh_label … ul with
1505    [ mk_Sig ret H ⇒
1506       do 〈packed_lbls, ul1〉 ← populate_lenv t (snd ?? ret) (add … lbls l (fst ?? ret));
1507       match packed_lbls with
1508       [ mk_Sig lbls' Hinv ⇒ OK ? 〈«lbls', ?», ul1〉 ]
1509    ]
1510  ] (refl ? (lookup_label lbls l))
1511].
1512[ 1: whd #l #l' #Hlookup %2 assumption
1513| 2: whd in Hinv; whd #cl_lab #cm_lab #Hlookup
1514     @(eq_identifier_elim … l cl_lab)
1515     [ 1: #Heq %1 >Heq whd %1 //
1516     | 2: #Hneq cases (Hinv cl_lab cm_lab Hlookup)
1517           [ 1: #H %1 %2 @H
1518           | 2: #LOOK' %2 >lookup_label_miss in LOOK'; /2/ #H @H ]
1519     ]
1520]
1521qed.
1522
1523definition build_label_env :
1524   ∀body:statement. res ((Σlbls:lenv. ∀l,l'.lookup_label lbls l = OK ? l' → Exists ? (λl'.l' = l) (labels_defined body)) × labgen) ≝
1525λbody.
1526  let initial_labgen ≝ mk_labgen (new_universe ?) (nil ?) ?  in
1527  do 〈label_map, u〉 ← populate_lenv (labels_defined body) initial_labgen (empty_map ??);
1528  let lbls ≝ pi1 ?? label_map in
1529  let H    ≝ pi2 ?? label_map in
1530  OK ? 〈«lbls, ?», u〉.
1531[ 1: #l #l' #E cases (H l l' E) //
1532     whd in ⊢ (??%? → ?); #H destruct
1533| 2: whd @I ]
1534qed.
1535
1536lemma local_id_split : ∀vars,tmpgen,i,t.
1537  local_id (add_tmps vars (tmp_env vars tmpgen)) i t →
1538  local_id vars i t ∨ Exists ? (λx. \fst x = i ∧ typ_of_type (\snd x) = t) (tmp_env … tmpgen).
1539#vars #tmpgen #i #t
1540whd in ⊢ (?%?? → ?);
1541elim (tmp_env vars tmpgen)
1542[ #H %1 @H
1543| * #id #ty #tl #IH
1544  cases (identifier_eq ? i id)
1545  [ #E >E #H %2 whd %1 % [ @refl | whd in H; whd in H:(match % with [_⇒?|_⇒?]); >lookup_add_hit in H; #E1 >E1 @refl ]
1546  | #NE #H cases (IH ?)
1547    [ #H' %1 @H'
1548    | #H' %2 %2 @H'
1549    | whd in H; whd in H:(match % with [ _ ⇒ ? | _ ⇒ ? ]);
1550      >lookup_add_miss in H; [ #H @H | @NE ]
1551    ]
1552  ]
1553] qed.
1554
1555lemma Exists_squeeze : ∀A,P,l1,l2,l3.
1556  Exists A P (l1@l3) → Exists A P (l1@l2@l3).
1557#A #P #l1 #l2 #l3 #EX
1558cases (Exists_append … EX)
1559[ #EX1 @Exists_append_l @EX1
1560| #EX3 @Exists_append_r @Exists_append_r @EX3
1561] qed.
1562
1563(* This lemma allows to merge two stmt_P in one. Used in the following parts to merge an invariant on variables
1564   and an invariant on labels. *)
1565lemma stmt_P_conj : ∀ (P1:stmt → Prop). ∀ (P2:stmt → Prop). ∀ s. stmt_P P1 s → stmt_P P2 s → stmt_P (λs.P1 s ∧ P2 s) s.
1566#P1 #P2 #s elim s
1567normalize /6 by proj1, proj2, conj/
1568qed.
1569
1570definition translate_function :
1571  ∀tmpuniverse:universe SymbolTag.
1572  ∀globals:list (ident×region×type).
1573  ∀f:function.
1574    globals_fresh_for_univ ? globals tmpuniverse →
1575    fn_fresh_for_univ f tmpuniverse →
1576  res internal_function ≝
1577λtmpuniverse, globals, f, Fglobals, Ffn.
1578  do 〈env_pack, ul〉 ← build_label_env (fn_body f);
1579    match env_pack with
1580    [ mk_Sig lbls Ilbls ⇒
1581      let 〈vartypes, stacksize〉 as E ≝ characterise_vars globals f in
1582      let uv ≝ mk_tmpgen vartypes tmpuniverse [ ] ?? in
1583      do s0 ← translate_statement vartypes uv ul lbls DoNotConvert (opttyp_of_type (fn_return f)) (fn_body f);
1584      do «fgens, s1, Is» ← alloc_params vartypes lbls ? uv DoNotConvert (opttyp_of_type (fn_return f)) (fn_params f) s0;
1585      let params ≝ map ?? (λv.〈\fst v, typ_of_type (\snd v)〉) (fn_params f) in
1586      let vars ≝ map ?? (λv.〈\fst v, typ_of_type (\snd v)〉) (tmp_env ? (fst ?? fgens) @ fn_vars f) in
1587      do D ← check_distinct_env ?? (params @ vars);
1588      OK ? (mk_internal_function
1589        (opttyp_of_type (fn_return f))
1590        params
1591        vars
1592        D
1593        stacksize
1594        s1 ?)
1595  ].
1596[ 1: #i #t #Hloc whd @Hloc
1597| 2: whd #id #Hpresent normalize in Hpresent:(???%?); whd in Hpresent;
1598      @(characterise_vars_fresh … (sym_eq … E)) //
1599| 3: @(match fgens return λx.x=fgens → ? with
1600     [ mk_Prod uv' ul' ⇒ λHfgens.? ] (refl ? fgens))
1601     whd in Is; <Hfgens in Is; #Is whd in Is ⊢ %;
1602     elim Is * * * #Hstmt_inv #Hlab_trans #Htmps_pres #Hreturn #Hlabel_wf
1603     (* merge Hlabel_wf with Hstmt_inv and eliminate right away *)
1604     @(stmt_P_mp … (stmt_P_conj … (stmt_P_conj … Hstmt_inv Hlabel_wf) Hreturn))
1605     #s * * #Hstmt_vars #Hstmt_labels #Hstmt_return %
1606     [ 1: (* prove that variables are either parameters or locals *)
1607        @(stmt_vars_mp … Hstmt_vars) #i #t #H
1608        (* Case analysis: (i, t) is either in vartypes, or in (tmp_env vartypes uv) *)
1609        cases (local_id_split … H)
1610        [ 1: #H' >map_append
1611          @Exists_map [ 1: #x @(And (\fst x = i) (typ_of_type (\snd x) = t))  (* * #id #ty @(〈id, typ_of_type ty〉=〈i, t〉)*)
1612                      | 2: whd @Exists_squeeze @(characterise_vars_all globals f ?? (sym_eq ??? E) i t H')
1613                      | 3: * #id #ty * #E1 #E2 <E1 <E2 @refl
1614                      ]
1615        | 2: #EX @Exists_append_r whd in ⊢ (???%); <map_append @Exists_append_l
1616          @Exists_map [ 1: #x @(And (\fst x = i) (typ_of_type (\snd x) = t))
1617                      | 2: <Hfgens @EX
1618                      | 3: * #id #ty * #E1 #E2 <E1 <E2 % @refl
1619                      ]
1620        ]
1621     | 2: (* prove that labels are properly declared. *)
1622          @(stmt_labels_mp … Hstmt_labels) #l * *
1623          [ 1: #H assumption
1624          | 2: * #cl_label #Hlookup lapply (Ilbls cl_label l Hlookup) #Hdefined
1625                cases (Hlab_trans … Hdefined) #lx * #LOOKUPx >LOOKUPx in Hlookup; #Ex destruct (Ex)
1626                #H @H
1627          ]
1628     | cases s in Hstmt_return; // * normalize [2: * #t #e ]
1629       cases (fn_return f) normalize #A try #B try #C try #D try #E destruct //
1630    ]
1631] qed.   
1632
1633definition translate_fundef :
1634  ∀tmpuniverse:universe SymbolTag.
1635  ∀globals:list (ident×region×type).
1636    globals_fresh_for_univ ? globals tmpuniverse →
1637  ∀f:clight_fundef.
1638    fd_fresh_for_univ f tmpuniverse →
1639  res (fundef internal_function) ≝
1640λtmpuniverse,globals,Fglobals,f.
1641match f return λf. fd_fresh_for_univ f ? → ? with
1642[ CL_Internal fn ⇒ λFf. do fn' ← translate_function tmpuniverse globals fn Fglobals Ff; OK ? (Internal ? fn')
1643| CL_External fn argtys retty ⇒ λ_. OK ? (External ? (mk_external_function fn (signature_of_type argtys retty)))
1644].
1645
1646let rec map_partial_All (A,B:Type[0]) (P:A → Prop) (f:∀a:A. P a → res B)
1647  (l:list A) (H:All A P l) on l : res (list B) ≝
1648match l return λl. All A P l → ? with
1649[ nil ⇒ λ_. OK (list B) (nil B)
1650| cons hd tl ⇒ λH.
1651    do b_hd ← f hd (proj1 … H);
1652    do b_tl ← map_partial_All A B P f tl (proj2 … H);
1653      OK (list B) (cons B b_hd b_tl)
1654] H.
1655
1656definition clight_to_cminor : clight_program → res Cminor_program ≝
1657λp.
1658  let tmpuniverse ≝ universe_for_program p in
1659  let fun_globals ≝ map ?? (λidf. 〈\fst idf,Code,type_of_fundef (\snd idf)〉) (prog_funct ?? p) in
1660  let var_globals ≝ map ?? (λv. 〈\fst (\fst v), \snd (\fst v), \snd (\snd v)〉) (prog_vars ?? p) in
1661  let globals ≝ fun_globals @ var_globals in
1662  do fns ← map_partial_All ??? (λx,H. do f ← translate_fundef tmpuniverse globals ? (\snd x) H; OK ? 〈\fst x, f〉) (prog_funct ?? p) ?;
1663    OK ? (mk_program ??
1664      (map ?? (λv. 〈\fst v, \fst (\snd v)〉) (prog_vars ?? p))
1665      fns
1666      (prog_main ?? p)).
1667cases (prog_fresh p) * #H1 #H2 #H3
1668[ @(All_mp … H1) #x * //
1669| @All_append
1670  [ elim (prog_funct ?? p) in H1 ⊢ %; // * #id #fd #tl #IH * * #Hhd1 #Hhd2 #Htl % // @IH @Htl
1671  | whd in H3; elim (prog_vars ?? p) in H3 ⊢ %; // #hd #tl #IH * #Hhd #Htl % /2/
1672  ]
1673] qed.
1674
1675(* It'd be nice to go back to some generic thing like
1676
1677 transform_partial_program2 … p (translate_fundef tmpuniverse globals) (λi. OK ? (\fst i)).
1678
1679   rather than the messier definition above.
1680*)
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