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1 706 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT COMPILER COMPONENTS                         --
4
--                                                                          --
5
--                              P A R . C H 2                               --
6
--                                                                          --
7
--                                 B o d y                                  --
8
--                                                                          --
9
--          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --
10
--                                                                          --
11
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12
-- terms of the  GNU General Public License as published  by the Free Soft- --
13
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17
-- for  more details.  You should have  received  a copy of the GNU General --
18
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
19
-- http://www.gnu.org/licenses for a complete copy of the license.          --
20
--                                                                          --
21
-- GNAT was originally developed  by the GNAT team at  New York University. --
22
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23
--                                                                          --
24
------------------------------------------------------------------------------
25
 
26
pragma Style_Checks (All_Checks);
27
--  Turn off subprogram body ordering check. Subprograms are in order
28
--  by RM section rather than alphabetical
29
 
30
separate (Par)
31
package body Ch2 is
32
 
33
   --  Local functions, used only in this chapter
34
 
35
   procedure Scan_Pragma_Argument_Association
36
     (Identifier_Seen : in out Boolean;
37
      Association     : out Node_Id);
38
   --  Scans out a pragma argument association. Identifier_Seen is true on
39
   --  entry if a previous association had an identifier, and gets set True if
40
   --  the scanned association has an identifier (this is used to check the
41
   --  rule that no associations without identifiers can follow an association
42
   --  which has an identifier). The result is returned in Association.
43
 
44
   ---------------------
45
   -- 2.3  Identifier --
46
   ---------------------
47
 
48
   --  IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT}
49
 
50
   --  LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT
51
 
52
   --  An IDENTIFIER shall not be a reserved word
53
 
54
   --  Error recovery: can raise Error_Resync (cannot return Error)
55
 
56
   function P_Identifier (C : Id_Check := None) return Node_Id is
57
      Ident_Node : Node_Id;
58
 
59
   begin
60
      --  All set if we do indeed have an identifier
61
 
62
      --  Code duplication, see Par_Ch3.P_Defining_Identifier???
63
 
64
      if Token = Tok_Identifier then
65
         Check_Future_Keyword;
66
         Ident_Node := Token_Node;
67
         Scan; -- past Identifier
68
         return Ident_Node;
69
 
70
      --  If we have a reserved identifier, manufacture an identifier with
71
      --  a corresponding name after posting an appropriate error message
72
 
73
      elsif Is_Reserved_Identifier (C) then
74
         Scan_Reserved_Identifier (Force_Msg => False);
75
         Ident_Node := Token_Node;
76
         Scan; -- past the node
77
         return Ident_Node;
78
 
79
      --  Otherwise we have junk that cannot be interpreted as an identifier
80
 
81
      else
82
         T_Identifier; -- to give message
83
         raise Error_Resync;
84
      end if;
85
   end P_Identifier;
86
 
87
   --------------------------
88
   -- 2.3  Letter Or Digit --
89
   --------------------------
90
 
91
   --  Parsed by P_Identifier (2.3)
92
 
93
   --------------------------
94
   -- 2.4  Numeric Literal --
95
   --------------------------
96
 
97
   --  NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL
98
 
99
   --  Numeric literal is returned by the scanner as either
100
   --  Tok_Integer_Literal or Tok_Real_Literal
101
 
102
   ----------------------------
103
   -- 2.4.1  Decimal Literal --
104
   ----------------------------
105
 
106
   --  DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT]
107
 
108
   --  Handled by scanner as part of numeric literal handing (see 2.4)
109
 
110
   --------------------
111
   -- 2.4.1  Numeral --
112
   --------------------
113
 
114
   --  NUMERAL ::= DIGIT {[UNDERLINE] DIGIT}
115
 
116
   --  Handled by scanner as part of numeric literal handling (see 2.4)
117
 
118
   ---------------------
119
   -- 2.4.1  Exponent --
120
   ---------------------
121
 
122
   --  EXPONENT ::= E [+] NUMERAL | E - NUMERAL
123
 
124
   --  Handled by scanner as part of numeric literal handling (see 2.4)
125
 
126
   --------------------------
127
   -- 2.4.2  Based Literal --
128
   --------------------------
129
 
130
   --  BASED_LITERAL ::=
131
   --   BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT]
132
 
133
   --  Handled by scanner as part of numeric literal handling (see 2.4)
134
 
135
   -----------------
136
   -- 2.4.2  Base --
137
   -----------------
138
 
139
   --  BASE ::= NUMERAL
140
 
141
   --  Handled by scanner as part of numeric literal handling (see 2.4)
142
 
143
   --------------------------
144
   -- 2.4.2  Based Numeral --
145
   --------------------------
146
 
147
   --  BASED_NUMERAL ::=
148
   --    EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT}
149
 
150
   --  Handled by scanner as part of numeric literal handling (see 2.4)
151
 
152
   ---------------------------
153
   -- 2.4.2  Extended Digit --
154
   ---------------------------
155
 
156
   --  EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F
157
 
158
   --  Handled by scanner as part of numeric literal handling (see 2.4)
159
 
160
   ----------------------------
161
   -- 2.5  Character Literal --
162
   ----------------------------
163
 
164
   --  CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER '
165
 
166
   --  Handled by the scanner and returned as Tok_Char_Literal
167
 
168
   -------------------------
169
   -- 2.6  String Literal --
170
   -------------------------
171
 
172
   --  STRING LITERAL ::= "{STRING_ELEMENT}"
173
 
174
   --  Handled by the scanner and returned as Tok_String_Literal
175
   --  or if the string looks like an operator as Tok_Operator_Symbol.
176
 
177
   -------------------------
178
   -- 2.6  String Element --
179
   -------------------------
180
 
181
   --  STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER
182
 
183
   --  A STRING_ELEMENT is either a pair of quotation marks ("),
184
   --  or a single GRAPHIC_CHARACTER other than a quotation mark.
185
 
186
   --  Handled by scanner as part of string literal handling (see 2.4)
187
 
188
   ------------------
189
   -- 2.7  Comment --
190
   ------------------
191
 
192
   --  A COMMENT starts with two adjacent hyphens and extends up to the
193
   --  end of the line. A COMMENT may appear on any line of a program.
194
 
195
   --  Handled by the scanner which simply skips past encountered comments
196
 
197
   -----------------
198
   -- 2.8  Pragma --
199
   -----------------
200
 
201
   --  PRAGMA ::= pragma IDENTIFIER
202
   --    [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})];
203
 
204
   --  The caller has checked that the initial token is PRAGMA
205
 
206
   --  Error recovery: cannot raise Error_Resync
207
 
208
   --  One special piece of processing is needed in this routine. As described
209
   --  in the section on "Handling semicolon used in place of IS" in module
210
   --  Parse, the parser detects the case of missing subprogram bodies to
211
   --  allow recovery from this syntactic error. Pragma INTERFACE (and, for
212
   --  Ada 95, pragma IMPORT) can appear in place of the body. The parser must
213
   --  recognize the use of these two pragmas in this context, otherwise it
214
   --  will think there are missing bodies, and try to change ; to IS, when
215
   --  in fact the bodies ARE present, supplied by these pragmas.
216
 
217
   function P_Pragma (Skipping : Boolean := False) return Node_Id is
218
      Interface_Check_Required : Boolean := False;
219
      --  Set True if check of pragma INTERFACE is required
220
 
221
      Import_Check_Required : Boolean := False;
222
      --  Set True if check of pragma IMPORT is required
223
 
224
      Arg_Count : Int := 0;
225
      --  Number of argument associations processed
226
 
227
      Identifier_Seen : Boolean := False;
228
      --  Set True if an identifier is encountered for a pragma argument. Used
229
      --  to check that there are no more arguments without identifiers.
230
 
231
      Prag_Node     : Node_Id;
232
      Prag_Name     : Name_Id;
233
      Semicolon_Loc : Source_Ptr;
234
      Ident_Node    : Node_Id;
235
      Assoc_Node    : Node_Id;
236
      Result        : Node_Id;
237
 
238
      procedure Skip_Pragma_Semicolon;
239
      --  Skip past semicolon at end of pragma
240
 
241
      ---------------------------
242
      -- Skip_Pragma_Semicolon --
243
      ---------------------------
244
 
245
      procedure Skip_Pragma_Semicolon is
246
      begin
247
         if Token /= Tok_Semicolon then
248
 
249
            --  If skipping the pragma, ignore a missing semicolon
250
 
251
            if Skipping then
252
               null;
253
 
254
            --  Otherwise demand a semicolon
255
 
256
            else
257
               T_Semicolon;
258
            end if;
259
 
260
         --  Scan past semicolon if present
261
 
262
         else
263
            Scan;
264
         end if;
265
      end Skip_Pragma_Semicolon;
266
 
267
   --  Start of processing for P_Pragma
268
 
269
   begin
270
      Prag_Node := New_Node (N_Pragma, Token_Ptr);
271
      Scan; -- past PRAGMA
272
      Prag_Name := Token_Name;
273
 
274
      if Style_Check then
275
         Style.Check_Pragma_Name;
276
      end if;
277
 
278
      --  Ada 2005 (AI-284): INTERFACE is a new reserved word but it is
279
      --  allowed as a pragma name.
280
 
281
      if Ada_Version >= Ada_2005
282
        and then Token = Tok_Interface
283
      then
284
         Prag_Name := Name_Interface;
285
         Ident_Node  := Make_Identifier (Token_Ptr, Name_Interface);
286
         Scan; -- past INTERFACE
287
      else
288
         Ident_Node := P_Identifier;
289
      end if;
290
 
291
      Set_Pragma_Identifier (Prag_Node, Ident_Node);
292
 
293
      --  See if special INTERFACE/IMPORT check is required
294
 
295
      if SIS_Entry_Active then
296
         Interface_Check_Required := (Prag_Name = Name_Interface);
297
         Import_Check_Required    := (Prag_Name = Name_Import);
298
      else
299
         Interface_Check_Required := False;
300
         Import_Check_Required    := False;
301
      end if;
302
 
303
      --  Scan arguments. We assume that arguments are present if there is
304
      --  a left paren, or if a semicolon is missing and there is another
305
      --  token on the same line as the pragma name.
306
 
307
      if Token = Tok_Left_Paren
308
        or else (Token /= Tok_Semicolon
309
                   and then not Token_Is_At_Start_Of_Line)
310
      then
311
         Set_Pragma_Argument_Associations (Prag_Node, New_List);
312
         T_Left_Paren;
313
 
314
         loop
315
            Arg_Count := Arg_Count + 1;
316
            Scan_Pragma_Argument_Association (Identifier_Seen, Assoc_Node);
317
 
318
            if Arg_Count = 2
319
              and then (Interface_Check_Required or else Import_Check_Required)
320
            then
321
               --  Here is where we cancel the SIS active status if this pragma
322
               --  supplies a body for the currently active subprogram spec.
323
 
324
               if Nkind (Expression (Assoc_Node)) in N_Direct_Name
325
                 and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl)
326
               then
327
                  SIS_Entry_Active := False;
328
               end if;
329
            end if;
330
 
331
            Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node));
332
            exit when Token /= Tok_Comma;
333
            Scan; -- past comma
334
         end loop;
335
 
336
         --  If we have := for pragma Debug, it is worth special casing the
337
         --  error message (it is easy to think of pragma Debug as taking a
338
         --  statement, and an assignment statement is the most likely
339
         --  candidate for this error)
340
 
341
         if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then
342
            Error_Msg_SC ("argument for pragma Debug must be procedure call");
343
            Resync_To_Semicolon;
344
 
345
         --  Normal case, we expect a right paren here
346
 
347
         else
348
            T_Right_Paren;
349
         end if;
350
      end if;
351
 
352
      Semicolon_Loc := Token_Ptr;
353
 
354
      --  Now we have two tasks left, we need to scan out the semicolon
355
      --  following the pragma, and we have to call Par.Prag to process
356
      --  the pragma. Normally we do them in this order, however, there
357
      --  is one exception namely pragma Style_Checks where we like to
358
      --  skip the semicolon after processing the pragma, since that way
359
      --  the style checks for the scanning of the semicolon follow the
360
      --  settings of the pragma.
361
 
362
      --  You might think we could just unconditionally do things in
363
      --  the opposite order, but there are other pragmas, notably the
364
      --  case of pragma Source_File_Name, which assume the semicolon
365
      --  is already scanned out.
366
 
367
      if Prag_Name = Name_Style_Checks then
368
         Result := Par.Prag (Prag_Node, Semicolon_Loc);
369
         Skip_Pragma_Semicolon;
370
         return Result;
371
      else
372
         Skip_Pragma_Semicolon;
373
         return Par.Prag (Prag_Node, Semicolon_Loc);
374
      end if;
375
 
376
   exception
377
      when Error_Resync =>
378
         Resync_Past_Semicolon;
379
         return Error;
380
 
381
   end P_Pragma;
382
 
383
   --  This routine is called if a pragma is encountered in an inappropriate
384
   --  position, the pragma is scanned out and control returns to continue.
385
 
386
   --  The caller has checked that the initial token is pragma
387
 
388
   --  Error recovery: cannot raise Error_Resync
389
 
390
   procedure P_Pragmas_Misplaced is
391
   begin
392
      while Token = Tok_Pragma loop
393
         Error_Msg_SC ("pragma not allowed here");
394
         Discard_Junk_Node (P_Pragma (Skipping => True));
395
      end loop;
396
   end P_Pragmas_Misplaced;
397
 
398
   --  This function is called to scan out an optional sequence of pragmas.
399
   --  If no pragmas are found, then No_List is returned.
400
 
401
   --  Error recovery: Cannot raise Error_Resync
402
 
403
   function P_Pragmas_Opt return List_Id is
404
      L : List_Id;
405
 
406
   begin
407
      if Token = Tok_Pragma then
408
         L := New_List;
409
         P_Pragmas_Opt (L);
410
         return L;
411
 
412
      else
413
         return No_List;
414
      end if;
415
   end P_Pragmas_Opt;
416
 
417
   --  This procedure is called to scan out an optional sequence of pragmas.
418
   --  Any pragmas found are appended to the list provided as an argument.
419
 
420
   --  Error recovery: Cannot raise Error_Resync
421
 
422
   procedure P_Pragmas_Opt (List : List_Id) is
423
      P     : Node_Id;
424
 
425
   begin
426
      while Token = Tok_Pragma loop
427
         P := P_Pragma;
428
 
429
         if Nkind (P) /= N_Error
430
          and then (Pragma_Name (P) = Name_Assert
431
                      or else
432
                    Pragma_Name (P) = Name_Debug)
433
         then
434
            Error_Msg_Name_1 := Pragma_Name (P);
435
            Error_Msg_N
436
              ("pragma% must be in declaration/statement context", P);
437
         else
438
            Append (P, List);
439
         end if;
440
      end loop;
441
   end P_Pragmas_Opt;
442
 
443
   --------------------------------------
444
   -- 2.8  Pragma_Argument Association --
445
   --------------------------------------
446
 
447
   --  PRAGMA_ARGUMENT_ASSOCIATION ::=
448
   --    [pragma_argument_IDENTIFIER =>] NAME
449
   --  | [pragma_argument_IDENTIFIER =>] EXPRESSION
450
 
451
   --  Error recovery: cannot raise Error_Resync
452
 
453
   procedure Scan_Pragma_Argument_Association
454
     (Identifier_Seen : in out Boolean;
455
      Association     : out Node_Id)
456
   is
457
      Scan_State      : Saved_Scan_State;
458
      Identifier_Node : Node_Id;
459
      Id_Present      : Boolean;
460
 
461
   begin
462
      Association := New_Node (N_Pragma_Argument_Association, Token_Ptr);
463
      Set_Chars (Association, No_Name);
464
 
465
      --  Argument starts with identifier
466
 
467
      if Token = Tok_Identifier then
468
         Identifier_Node := Token_Node;
469
         Save_Scan_State (Scan_State); -- at Identifier
470
         Scan; -- past Identifier
471
 
472
         if Token = Tok_Arrow then
473
            Identifier_Seen := True;
474
            Scan; -- past arrow
475
            Set_Chars (Association, Chars (Identifier_Node));
476
            Id_Present := True;
477
 
478
         --  Case of argument with no identifier
479
 
480
         else
481
            Restore_Scan_State (Scan_State); -- to Identifier
482
            Id_Present := False;
483
         end if;
484
 
485
      --  Argument does not start with identifier
486
 
487
      else
488
         Id_Present := False;
489
      end if;
490
 
491
      --  Diagnose error of "positional" argument for pragma appearing after
492
      --  a "named" argument (quotes here are because that's not quite accurate
493
      --  Ada RM terminology).
494
 
495
      --  Since older GNAT versions did not generate this error, disable this
496
      --  message in codepeer mode to help legacy code using codepeer.
497
 
498
      if Identifier_Seen and not Id_Present and not CodePeer_Mode then
499
         Error_Msg_SC ("|pragma argument identifier required here");
500
         Error_Msg_SC ("\since previous argument had identifier (RM 2.8(4))");
501
      end if;
502
 
503
      if Id_Present then
504
         Set_Expression (Association, P_Expression);
505
      else
506
         Set_Expression (Association, P_Expression_If_OK);
507
      end if;
508
   end Scan_Pragma_Argument_Association;
509
 
510
end Ch2;

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