summary refs log tree commit diff
path: root/source/mod_student/typechecker.ml
blob: 95e9157a747a7264da8826b19e451235215bd131 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
open Xi_lib
open Ast
(* W Xi_lib.Types są definicje typów i środowiska typowego *)
open Types

module Make() = struct

  (* Logger: używa się go jak Format.printf *)
  let logf fmt = Logger.make_logf __MODULE__ fmt

  module Check () = struct

    (* Zgłaszaczka błędów *)
    module ErrorReporter = Typechecker_errors.MakeOneShotErrorReporter ()

    (* Hashtablica którą zwracamy jak wszystko jest OK.
     * Mapuje znacznik węzła na przypisany typ. Dzięki tej tablicy
     * późniejsze etapy kompilatora będą miały dostęp do policzonych
     * typów wyrażeń 
     * 
     * Jeżeli typowanie się powiedzie to zawartość tablicy wydrukuje się
     * do pliku xilog/004.typechecking.types
     *)
    let node2type_map = Hashtbl.create 513

    let rec te2type_ret = function
      | TEXPR_Int _ -> TP_Int
      | TEXPR_Bool _ -> TP_Bool
      | TEXPR_Array {sub;dim=None;_} -> TP_Array (te2type_ret sub)
      | TEXPR_Array {sub;dim;loc} -> ErrorReporter.report_array_initialization_forbidden ~loc
    (* --------------------------------------------------- *)
    (* Funkcja nakładka na inferencję, jej zadanie to uzupełniać hashtablicę node2type_map *)
    let rec infer_expression env e =
      let tp = _infer_expression env e in
      Hashtbl.replace node2type_map (tag_of_expression e) tp;
      logf "%s: inferred type %s"
        (string_of_location
        (location_of_expression e))
        (string_of_normal_type tp);
      tp

    (* --------------------------------------------------- *)
    (* Oddolna strategia *)
    and _infer_expression env = function
      | EXPR_Id {id; loc; _} ->
        begin
          match TypingEnvironment.lookup id env with
          | None -> ErrorReporter.report_unknown_identifier ~loc ~id
          | Some tp -> match tp with
                       | ENVTP_Var tp -> tp
                       | ENVTP_Fn (_,_) -> ErrorReporter.report_identifier_is_not_variable ~loc ~id
        end

      | EXPR_Int _ ->
        TP_Int

      | EXPR_Char _ ->
        TP_Int

      | EXPR_Bool _ ->
        TP_Bool

      | EXPR_Index {expr;index;loc; _} ->
        check_expression env  TP_Int index;
        begin
          match  infer_expression env expr with
          | TP_Array tp -> tp
          | TP_Int   -> ErrorReporter.report_expected_array ~loc ~actual:TP_Int
          | TP_Bool  -> ErrorReporter.report_expected_array ~loc ~actual:TP_Bool
        end
      | EXPR_Call call ->
        check_function_call env call

      | EXPR_Length {arg;loc;_} ->
        begin
          match infer_expression env arg with
          | TP_Array _ -> TP_Int
          | TP_Int   -> ErrorReporter.report_expected_array ~loc ~actual:TP_Int
          | TP_Bool  -> ErrorReporter.report_expected_array ~loc ~actual:TP_Bool
        end

      | EXPR_Relation {lhs; rhs; op=RELOP_Ge; _} 
      | EXPR_Relation {lhs; rhs; op=RELOP_Gt; _} 
      | EXPR_Relation {lhs; rhs; op=RELOP_Lt; _} 
      | EXPR_Relation {lhs; rhs; op=RELOP_Le; _}  ->
        check_expression env TP_Int lhs;
        check_expression env TP_Int rhs;
        TP_Bool

      | EXPR_Relation {lhs; rhs; op=RELOP_Eq; _} 
      | EXPR_Relation {lhs; rhs; op=RELOP_Ne; _} ->
        let tp = infer_expression env lhs in
        check_expression env tp rhs;
        TP_Bool
        (* Consider backtracking *)

        (* Reguła dla dodawania, jak w treści zadania *)
      | EXPR_Binop {loc; lhs; rhs; op=BINOP_Add; _} ->
        begin match infer_expression env lhs with
        | (TP_Array _) as tp
        | (TP_Int as tp) ->
          check_expression env tp rhs;
          tp
        | _ ->
          let descr = "operator + expects integer or array" in
         ErrorReporter.report_other_error ~loc ~descr
        end

      | EXPR_Binop {lhs; rhs; op=BINOP_And;_} 
      | EXPR_Binop {lhs; rhs; op=BINOP_Or; _} ->
        check_expression env TP_Bool lhs;
        check_expression env TP_Bool rhs;
        TP_Bool

      | EXPR_Binop {lhs; rhs; op=BINOP_Sub;_} 
      | EXPR_Binop {lhs; rhs; op=BINOP_Rem;_} 
      | EXPR_Binop {lhs; rhs; op=BINOP_Mult;_} 
      | EXPR_Binop {lhs; rhs; op=BINOP_Div; _} ->
        check_expression env TP_Int lhs;
        check_expression env TP_Int rhs;
        TP_Int

      | EXPR_Unop {op=UNOP_Neg; sub; _} ->
        check_expression env TP_Int sub;
        TP_Int

      | EXPR_Unop {op=UNOP_Not; sub; _} ->
        check_expression env TP_Bool sub;
        TP_Bool

      | EXPR_String _ ->
        TP_Array TP_Int

      | EXPR_Struct {elements=[]; loc; _} ->
        ErrorReporter.report_cannot_infer ~loc

      | EXPR_Struct {elements=x::xs; _} ->
        let t=infer_expression env x in
        let _=List.map (check_expression env t) xs in
        TP_Array t

    and check_function_call env (Call {loc;callee;_} as call)=
      match check_function_args env call with
      | [] -> ErrorReporter.report_other_error ~loc ~descr:("Procedures don't return expressions")
      | [x] ->x
      | _  -> ErrorReporter.report_expected_function_returning_one_value ~loc ~id:callee
    and check_function_args env (Call {loc;callee;arguments;_})  =
      begin
      match TypingEnvironment.lookup callee env with
        | None -> ErrorReporter.report_unknown_identifier ~loc ~id:callee
        | Some ENVTP_Var _ -> ErrorReporter.report_identifier_is_not_callable ~loc ~id:callee
        | Some (ENVTP_Fn (arg_types,ret_types)) ->
        begin
          let rec aux args types = match args,types with
            | [],[] -> ()
            | arg::args, t::ts -> check_expression env t arg;aux args ts
            | _,[] -> ErrorReporter.report_bad_number_of_arguments ~loc ~expected:(List.length arg_types) ~actual:(List.length arguments)
            | [],_ -> ErrorReporter.report_bad_number_of_arguments ~loc ~expected:(List.length arg_types) ~actual:(List.length arguments)
          in aux arguments arg_types;
          ret_types
        end
      end
    and te2base env = begin function
        | TEXPR_Int _ -> TP_Int
        | TEXPR_Bool _ -> TP_Bool
        | TEXPR_Array {sub;dim=None;loc} -> ErrorReporter.report_array_initialization_forbidden ~loc
        | TEXPR_Array {sub;dim=Some x;_} -> check_expression env TP_Int x;TP_Array (te2base env sub)
      end
    and te2type_decl env = begin function
        | TEXPR_Int _ -> TP_Int
        | TEXPR_Bool _ -> TP_Bool
        | TEXPR_Array {sub;dim=None;_} -> TP_Array (te2type_decl env sub)
        | TEXPR_Array {sub;dim=Some x;_} -> check_expression env TP_Int x;TP_Array (te2base env sub)
      end
    and add_var_decl env (VarDecl {loc;id;tp}) = 
        match TypingEnvironment.add id (ENVTP_Var (te2type_decl env tp)) env with
        | (env,true) -> env
        | (env,false) -> ErrorReporter.report_shadows_previous_definition ~loc ~id
    (* --------------------------------------------------- *)
    (* Odgórna strategia: zapish w node2type_map oczekiwanie a następnie
     * sprawdź czy nie zachodzi specjalny przypadek. *)
    and check_expression env expected e =
      logf "%s: checking expression against %s"
        (string_of_location (location_of_expression e))
        (string_of_normal_type expected);
      Hashtbl.replace node2type_map (tag_of_expression e) expected;

      (* Sprawdzamy specjalne przypadki *)
      match e, expected with
          (* Mamy sprawdzić `{elements...}` kontra `tp[]`, czyli sprawdzamy 
          * elementy kontra typ elementu tablicy `tp` *)
      | EXPR_Struct {elements; _}, TP_Array tp ->
        List.iter (check_expression env tp) elements
      | EXPR_Binop {op=BINOP_And; lhs; rhs;_}, TP_Int ->
        check_expression env TP_Int lhs;
        check_expression env TP_Int rhs
      | EXPR_Binop {op=BINOP_And; lhs; rhs;_}, (TP_Array tp as t) ->
        check_expression env t lhs;
        check_expression env t rhs
      | EXPR_Index {expr;index;loc; _}, tp ->
        check_expression env  TP_Int index;
        check_expression env (TP_Array tp) expr
      (* ========== !! Zaimplementuj pozostale przypadki !! =========  *)

      (* Fallback do strategii oddolnej *)
      | _ ->
        let actual = infer_expression env e in
        if actual <> expected then
          ErrorReporter.report_type_mismatch
            ~loc:(location_of_expression e)
            ~actual
            ~expected

    (* --------------------------------------------------- *)
    (* Pomocnicza funkcja do sprawdzania wywołania procedury *)

    let check_procedure_call env (Call {loc;_} as call) : unit = 
        match check_function_args env call with
        | [] -> ()
        | _ -> ErrorReporter.report_other_error ~loc ~descr:"Function used as procedure"

    (* --------------------------------------------------- *)
    (* Rekonstrukcja typu dla lvalue *)

    let infer_lvalue env = function
      | LVALUE_Id {id;loc;_} -> 
      begin
        match TypingEnvironment.lookup id env with
        | None -> ErrorReporter.report_unknown_identifier ~loc ~id
        | Some ENVTP_Fn _ -> ErrorReporter.report_identifier_is_not_variable ~loc ~id
        | Some ENVTP_Var tp ->tp
      end

      | LVALUE_Index {index; sub; loc} ->
        check_expression env TP_Int index;
        begin
          match infer_expression env sub with
            | TP_Int -> ErrorReporter.report_expected_array ~loc ~actual:TP_Int
            | TP_Bool -> ErrorReporter.report_expected_array ~loc ~actual:TP_Bool
            | TP_Array tp -> tp
        end


    (* --------------------------------------------------- *)
    (* Sprawdzanie statementów *)

    let rec check_statement env = function
      (* Proste, wyinferuj typ `lhs` i sprawdź `rhs` kontra wynik *)
      | STMT_Assign {lhs; rhs; _} ->
        let lhs_tp = infer_lvalue env lhs in
        check_expression env lhs_tp rhs;
        env, RT_Unit

      | STMT_MultiVarDecl {vars; init; loc} ->
        begin
          let ret_types=check_function_args env init in
          let expected = List.length ret_types in
          let actual = List.length vars in
          match init with Call {loc;callee;_} ->
          if expected!=actual then ErrorReporter.report_expected_function_returning_many_values ~loc ~id:callee ~expected ~actual else
          begin
            let rec aux vars types bindings= match vars,types with
              | []          , []       -> bindings
              | None::vars  , t::types -> aux vars types bindings
              | (Some (VarDecl{tp;loc;id} as v) )::vars, t::types ->
                let expected =te2type_decl env tp in
                if expected==t then aux vars types (v::bindings)
                else ErrorReporter.report_binding_type_mismatch ~loc ~expected ~id ~actual:t
              | _ -> failwith "Should not happen"
            in (List.fold_left add_var_decl env (aux vars ret_types [])),RT_Unit
          end
        end

      | STMT_Block body ->
        check_statement_block env body

      | STMT_Call call ->
        check_procedure_call env call;
        env, RT_Unit

      | STMT_If {cond;then_branch;else_branch; _} ->
        check_expression env TP_Bool cond;
        let if_ret = snd(check_statement env then_branch) in
        begin
          match else_branch with 
          | None -> env,RT_Unit
          | Some else_branch -> let else_ret =snd(check_statement env else_branch) in
            env, (if if_ret==RT_Void && else_ret==RT_Void then RT_Void else RT_Unit)
        end

      | STMT_Return {values;loc} ->
        begin
          match TypingEnvironment.get_return env with
          | None -> begin
                      match values with
                      | [] -> env,RT_Void
                      | _ -> ErrorReporter.report_procedure_cannot_return_value ~loc
                    end
          | Some ret ->(
            let expected = List.length ret
            and actual   = List.length values in
              if actual==0 then ErrorReporter.report_function_must_return_something ~loc
              else
              let rec aux rets values = match rets,values with
                | ([],[]) -> env, RT_Void
                | ((r::rs) , (v::vs)) -> let _=check_expression env r v in aux rs vs
                | ([],(x::xs)) -> ErrorReporter.report_bad_number_of_return_values ~loc ~expected ~actual
                | ((x::xs),[]) -> ErrorReporter.report_bad_number_of_return_values ~loc ~expected ~actual
              in aux ret values)

        end

      | STMT_VarDecl {var; init} ->
        begin
        match var with 
        | VarDecl {tp;_} ->
          let t=te2type_decl env tp in
            begin
              match init with
              | Some init -> check_expression env t init
              | None -> ()
            end;
          (add_var_decl env var),RT_Unit
        end

      | STMT_While {cond; body; _} ->
        check_expression env TP_Bool cond;
        let _ = check_statement env body in
        env,RT_Unit

    and check_statement_block env (STMTBlock {body; _}) =
        let rec aux env = function
          | []  -> env,RT_Unit
          | [x] -> check_statement env x
          | x::xs ->
          begin match check_statement env x with
                | (env,RT_Unit) -> aux env xs
                | (env,RT_Void) -> ErrorReporter.report_other_error ~loc:(location_of_statement x) ~descr:"Return not at the end of block - unreachable code"
          end
        in env,(snd (aux env body))

    (* --------------------------------------------------- *)
    (* Top-level funkcje *)

    let check_global_declaration env = function
      | GDECL_Function {formal_parameters; return_types; body; loc; id; _} ->
        (* Sprawdź wszystko *)
        let env = List.fold_left add_var_decl env formal_parameters in
        match body with
        | Some body -> begin
                      match check_statement_block  (TypingEnvironment.set_return env (List.map te2type_ret return_types)) body with
                        | _, RT_Unit -> if return_types!=[] then ErrorReporter.report_not_all_control_paths_return_value ~loc ~id else ()
                        | _, RT_Void -> ()
                        end
        | None -> ()

    let scan_global_declaration env = function
      | GDECL_Function {id; formal_parameters; return_types; loc; _} ->
         match TypingEnvironment.add id (ENVTP_Fn ((List.map (fun (VarDecl x) -> te2type_ret(x.tp)) formal_parameters),(List.map te2type_ret return_types)) ) env with
        | (env,true)  -> env
        | (env,false) -> ErrorReporter.report_shadows_previous_definition ~loc ~id

    let scan_module env (ModuleDefinition {global_declarations; _}) =
      List.fold_left scan_global_declaration env global_declarations

    let check_module env (ModuleDefinition {global_declarations; _}) =
      List.iter (check_global_declaration env) global_declarations

    (* --------------------------------------------------- *)
    (* Przetwórz moduł *)
    let process_module env mdef =
      (* Wpierw przeskanuj globalne definicje aby uzupełnić środowisko *)
      let env = scan_module env mdef in
      (* Zweryfikuj wszystko *)
      check_module env mdef

    let computation mdef = 
      (* Zaczynamy z pustym środowiskiem *)
      let env = TypingEnvironment.empty in
      process_module env mdef;
      node2type_map
  end

  (* --------------------------------------------------- *)
  (* Procedura wejściowa *)
  let check_module mdef =
    (* Stwórz instancję typecheckera i ją odpal *)
    let module M = Check() in
    M.ErrorReporter.wrap M.computation mdef 

end