summaryrefslogtreecommitdiff
path: root/gcc/ada/par-prag.adb
blob: d51ed2ec20bf003e7469f9362966acdef6bbcc5f (plain)
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
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             P A R . P R A G                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  Generally the parser checks the basic syntax of pragmas, but does not
--  do specialized syntax checks for individual pragmas, these are deferred
--  to semantic analysis time (see unit Sem_Prag). There are some pragmas
--  which require recognition and either partial or complete processing
--  during parsing, and this unit performs this required processing.

with Fname.UF; use Fname.UF;
with Osint;    use Osint;
with Rident;   use Rident;
with Restrict; use Restrict;
with Stringt;  use Stringt;
with Stylesw;  use Stylesw;
with Uintp;    use Uintp;
with Uname;    use Uname;

with System.WCh_Con; use System.WCh_Con;

separate (Par)

function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id is
   Pragma_Name : constant Name_Id    := Chars (Pragma_Node);
   Prag_Id     : constant Pragma_Id  := Get_Pragma_Id (Pragma_Name);
   Pragma_Sloc : constant Source_Ptr := Sloc (Pragma_Node);
   Arg_Count   : Nat;
   Arg_Node    : Node_Id;

   -----------------------
   -- Local Subprograms --
   -----------------------

   function Arg1 return Node_Id;
   function Arg2 return Node_Id;
   function Arg3 return Node_Id;
   --  Obtain specified Pragma_Argument_Association. It is allowable to call
   --  the routine for the argument one past the last present argument, but
   --  that is the only case in which a non-present argument can be referenced.

   procedure Check_Arg_Count (Required : Int);
   --  Check argument count for pragma = Required.
   --  If not give error and raise Error_Resync.

   procedure Check_Arg_Is_String_Literal (Arg : Node_Id);
   --  Check the expression of the specified argument to make sure that it
   --  is a string literal. If not give error and raise Error_Resync.

   procedure Check_Arg_Is_On_Or_Off (Arg : Node_Id);
   --  Check the expression of the specified argument to make sure that it
   --  is an identifier which is either ON or OFF, and if not, then issue
   --  an error message and raise Error_Resync.

   procedure Check_No_Identifier (Arg : Node_Id);
   --  Checks that the given argument does not have an identifier. If
   --  an identifier is present, then an error message is issued, and
   --  Error_Resync is raised.

   procedure Check_Optional_Identifier (Arg : Node_Id; Id : Name_Id);
   --  Checks if the given argument has an identifier, and if so, requires
   --  it to match the given identifier name. If there is a non-matching
   --  identifier, then an error message is given and Error_Resync raised.

   procedure Check_Required_Identifier (Arg : Node_Id; Id : Name_Id);
   --  Same as Check_Optional_Identifier, except that the name is required
   --  to be present and to match the given Id value.

   procedure Process_Restrictions_Or_Restriction_Warnings;
   --  Common processing for Restrictions and Restriction_Warnings pragmas.
   --  This routine only processes the case of No_Obsolescent_Features,
   --  which is the only restriction that has syntactic effects. No general
   --  error checking is done, since this will be done in Sem_Prag. The
   --  other case processed is pragma Restrictions No_Dependence, since
   --  otherwise this is done too late.

   ----------
   -- Arg1 --
   ----------

   function Arg1 return Node_Id is
   begin
      return First (Pragma_Argument_Associations (Pragma_Node));
   end Arg1;

   ----------
   -- Arg2 --
   ----------

   function Arg2 return Node_Id is
   begin
      return Next (Arg1);
   end Arg2;

   ----------
   -- Arg3 --
   ----------

   function Arg3 return Node_Id is
   begin
      return Next (Arg2);
   end Arg3;

   ---------------------
   -- Check_Arg_Count --
   ---------------------

   procedure Check_Arg_Count (Required : Int) is
   begin
      if Arg_Count /= Required then
         Error_Msg ("wrong number of arguments for pragma%", Pragma_Sloc);
         raise Error_Resync;
      end if;
   end Check_Arg_Count;

   ----------------------------
   -- Check_Arg_Is_On_Or_Off --
   ----------------------------

   procedure Check_Arg_Is_On_Or_Off (Arg : Node_Id) is
      Argx : constant Node_Id := Expression (Arg);

   begin
      if Nkind (Expression (Arg)) /= N_Identifier
        or else (Chars (Argx) /= Name_On
                   and then
                 Chars (Argx) /= Name_Off)
      then
         Error_Msg_Name_2 := Name_On;
         Error_Msg_Name_3 := Name_Off;

         Error_Msg
           ("argument for pragma% must be% or%", Sloc (Argx));
         raise Error_Resync;
      end if;
   end Check_Arg_Is_On_Or_Off;

   ---------------------------------
   -- Check_Arg_Is_String_Literal --
   ---------------------------------

   procedure Check_Arg_Is_String_Literal (Arg : Node_Id) is
   begin
      if Nkind (Expression (Arg)) /= N_String_Literal then
         Error_Msg
           ("argument for pragma% must be string literal",
             Sloc (Expression (Arg)));
         raise Error_Resync;
      end if;
   end Check_Arg_Is_String_Literal;

   -------------------------
   -- Check_No_Identifier --
   -------------------------

   procedure Check_No_Identifier (Arg : Node_Id) is
   begin
      if Chars (Arg) /= No_Name then
         Error_Msg_N ("pragma% does not permit named arguments", Arg);
         raise Error_Resync;
      end if;
   end Check_No_Identifier;

   -------------------------------
   -- Check_Optional_Identifier --
   -------------------------------

   procedure Check_Optional_Identifier (Arg : Node_Id; Id : Name_Id) is
   begin
      if Present (Arg) and then Chars (Arg) /= No_Name then
         if Chars (Arg) /= Id then
            Error_Msg_Name_2 := Id;
            Error_Msg_N ("pragma% argument expects identifier%", Arg);
         end if;
      end if;
   end Check_Optional_Identifier;

   -------------------------------
   -- Check_Required_Identifier --
   -------------------------------

   procedure Check_Required_Identifier (Arg : Node_Id; Id : Name_Id) is
   begin
      if Chars (Arg) /= Id then
         Error_Msg_Name_2 := Id;
         Error_Msg_N ("pragma% argument must have identifier%", Arg);
      end if;
   end Check_Required_Identifier;

   --------------------------------------------------
   -- Process_Restrictions_Or_Restriction_Warnings --
   --------------------------------------------------

   procedure Process_Restrictions_Or_Restriction_Warnings is
      Arg  : Node_Id;
      Id   : Name_Id;
      Expr : Node_Id;

   begin
      Arg := Arg1;
      while Present (Arg) loop
         Id := Chars (Arg);
         Expr := Expression (Arg);

         if Id = No_Name
           and then Nkind (Expr) = N_Identifier
           and then Get_Restriction_Id (Chars (Expr)) = No_Obsolescent_Features
         then
            Set_Restriction (No_Obsolescent_Features, Pragma_Node);
            Restriction_Warnings (No_Obsolescent_Features) :=
              Prag_Id = Pragma_Restriction_Warnings;

         elsif Id = Name_No_Dependence then
            Set_Restriction_No_Dependence
              (Unit => Expr,
               Warn => Prag_Id = Pragma_Restriction_Warnings);
         end if;

         Next (Arg);
      end loop;
   end Process_Restrictions_Or_Restriction_Warnings;

--  Start if processing for Prag

begin
   Error_Msg_Name_1 := Pragma_Name;

   --  Ignore unrecognized pragma. We let Sem post the warning for this, since
   --  it is a semantic error, not a syntactic one (we have already checked
   --  the syntax for the unrecognized pragma as required by (RM 2.8(11)).

   if Prag_Id = Unknown_Pragma then
      return Pragma_Node;
   end if;

   --  Count number of arguments. This loop also checks if any of the arguments
   --  are Error, indicating a syntax error as they were parsed. If so, we
   --  simply return, because we get into trouble with cascaded errors if we
   --  try to perform our error checks on junk arguments.

   Arg_Count := 0;

   if Present (Pragma_Argument_Associations (Pragma_Node)) then
      Arg_Node := Arg1;

      while Arg_Node /= Empty loop
         Arg_Count := Arg_Count + 1;

         if Expression (Arg_Node) = Error then
            return Error;
         end if;

         Next (Arg_Node);
      end loop;
   end if;

   --  Remaining processing is pragma dependent

   case Prag_Id is

      ------------
      -- Ada_83 --
      ------------

      --  This pragma must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax.

      when Pragma_Ada_83 =>
         Ada_Version := Ada_83;
         Ada_Version_Explicit := Ada_Version;

      ------------
      -- Ada_95 --
      ------------

      --  This pragma must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax.

      when Pragma_Ada_95 =>
         Ada_Version := Ada_95;
         Ada_Version_Explicit := Ada_Version;

      ---------------------
      -- Ada_05/Ada_2005 --
      ---------------------

      --  This pragma must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax. However, it is only the zero argument form that
      --  must be processed at parse time.

      when Pragma_Ada_05 | Pragma_Ada_2005 =>
         if Arg_Count = 0 then
            Ada_Version := Ada_05;
            Ada_Version_Explicit := Ada_05;
         end if;

      -----------
      -- Debug --
      -----------

      --  pragma Debug (PROCEDURE_CALL_STATEMENT);

      --  This has to be processed by the parser because of the very peculiar
      --  form of the second parameter, which is syntactically from a formal
      --  point of view a function call (since it must be an expression), but
      --  semantically we treat it as a procedure call (which has exactly the
      --  same syntactic form, so that's why we can get away with this!)

      when Pragma_Debug => Debug : declare
         Expr : Node_Id;

      begin
         if Arg_Count = 2 then
            Check_No_Identifier (Arg1);
            Check_No_Identifier (Arg2);
            Expr := New_Copy (Expression (Arg2));

         else
            Check_Arg_Count (1);
            Check_No_Identifier (Arg1);
            Expr := New_Copy (Expression (Arg1));
         end if;

         if Nkind (Expr) /= N_Indexed_Component
           and then Nkind (Expr) /= N_Function_Call
           and then Nkind (Expr) /= N_Identifier
           and then Nkind (Expr) /= N_Selected_Component
         then
            Error_Msg
              ("argument of pragma% is not procedure call", Sloc (Expr));
            raise Error_Resync;
         else
            Set_Debug_Statement
              (Pragma_Node, P_Statement_Name (Expr));
         end if;
      end Debug;

      -------------------------------
      -- Extensions_Allowed (GNAT) --
      -------------------------------

      --  pragma Extensions_Allowed (Off | On)

      --  The processing for pragma Extensions_Allowed must be done at
      --  parse time, since extensions mode may affect what is accepted.

      when Pragma_Extensions_Allowed =>
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         Check_Arg_Is_On_Or_Off (Arg1);

         if Chars (Expression (Arg1)) = Name_On then
            Extensions_Allowed := True;
         else
            Extensions_Allowed := False;
         end if;

      ----------------
      -- List (2.8) --
      ----------------

      --  pragma List (Off | On)

      --  The processing for pragma List must be done at parse time,
      --  since a listing can be generated in parse only mode.

      when Pragma_List =>
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         Check_Arg_Is_On_Or_Off (Arg1);

         --  We unconditionally make a List_On entry for the pragma, so that
         --  in the List (Off) case, the pragma will print even in a region
         --  of code with listing turned off (this is required!)

         List_Pragmas.Increment_Last;
         List_Pragmas.Table (List_Pragmas.Last) :=
           (Ptyp => List_On, Ploc => Sloc (Pragma_Node));

         --  Now generate the list off entry for pragma List (Off)

         if Chars (Expression (Arg1)) = Name_Off then
            List_Pragmas.Increment_Last;
            List_Pragmas.Table (List_Pragmas.Last) :=
              (Ptyp => List_Off, Ploc => Semi);
         end if;

      ----------------
      -- Page (2.8) --
      ----------------

      --  pragma Page;

      --  Processing for this pragma must be done at parse time, since a
      --  listing can be generated in parse only mode with semantics off.

      when Pragma_Page =>
         Check_Arg_Count (0);
         List_Pragmas.Increment_Last;
         List_Pragmas.Table (List_Pragmas.Last) := (Page, Semi);

         ------------------
         -- Restrictions --
         ------------------

         --  pragma Restrictions (RESTRICTION {, RESTRICTION});

         --  RESTRICTION ::=
         --    restriction_IDENTIFIER
         --  | restriction_parameter_IDENTIFIER => EXPRESSION

         --  We process the case of No_Obsolescent_Features, since this has
         --  a syntactic effect that we need to detect at parse time (the use
         --  of replacement characters such as colon for pound sign).

         when Pragma_Restrictions =>
            Process_Restrictions_Or_Restriction_Warnings;

         --------------------------
         -- Restriction_Warnings --
         --------------------------

         --  pragma Restriction_Warnings (RESTRICTION {, RESTRICTION});

         --  RESTRICTION ::=
         --    restriction_IDENTIFIER
         --  | restriction_parameter_IDENTIFIER => EXPRESSION

         --  See above comment for pragma Restrictions

         when Pragma_Restriction_Warnings =>
            Process_Restrictions_Or_Restriction_Warnings;

      ----------------------------------------------------------
      -- Source_File_Name and Source_File_Name_Project (GNAT) --
      ----------------------------------------------------------

      --  These two pragmas have the same syntax and semantics.
      --  There are five forms of these pragmas:

      --  pragma Source_File_Name[_Project] (
      --    [UNIT_NAME      =>] unit_NAME,
      --     BODY_FILE_NAME =>  STRING_LITERAL
      --    [, [INDEX =>] INTEGER_LITERAL]);

      --  pragma Source_File_Name[_Project] (
      --    [UNIT_NAME      =>] unit_NAME,
      --     SPEC_FILE_NAME =>  STRING_LITERAL
      --    [, [INDEX =>] INTEGER_LITERAL]);

      --  pragma Source_File_Name[_Project] (
      --     BODY_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT => STRING_LITERAL]
      --  [, CASING          => CASING_SPEC]);

      --  pragma Source_File_Name[_Project] (
      --     SPEC_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT => STRING_LITERAL]
      --  [, CASING          => CASING_SPEC]);

      --  pragma Source_File_Name[_Project] (
      --     SUBUNIT_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT    => STRING_LITERAL]
      --  [, CASING             => CASING_SPEC]);

      --  CASING_SPEC ::= Uppercase | Lowercase | Mixedcase

      --  Pragma Source_File_Name_Project (SFNP) is equivalent to pragma
      --  Source_File_Name (SFN), however their usage is exclusive:
      --  SFN can only be used when no project file is used, while
      --  SFNP can only be used when a project file is used.

      --  The Project Manager produces a configuration pragmas file that
      --  is communicated to the compiler with -gnatec switch. This file
      --  contains only SFNP pragmas (at least two for the default naming
      --  scheme. As this configuration pragmas file is always the first
      --  processed by the compiler, it prevents the use of pragmas SFN in
      --  other config files when a project file is in use.

      --  Note: we process this during parsing, since we need to have the
      --  source file names set well before the semantic analysis starts,
      --  since we load the spec and with'ed packages before analysis.

      when Pragma_Source_File_Name | Pragma_Source_File_Name_Project =>
         Source_File_Name : declare
            Unam  : Unit_Name_Type;
            Expr1 : Node_Id;
            Pat   : String_Ptr;
            Typ   : Character;
            Dot   : String_Ptr;
            Cas   : Casing_Type;
            Nast  : Nat;
            Expr  : Node_Id;
            Index : Nat;

            function Get_Fname (Arg : Node_Id) return File_Name_Type;
            --  Process file name from unit name form of pragma

            function Get_String_Argument (Arg : Node_Id) return String_Ptr;
            --  Process string literal value from argument

            procedure Process_Casing (Arg : Node_Id);
            --  Process Casing argument of pattern form of pragma

            procedure Process_Dot_Replacement (Arg : Node_Id);
            --  Process Dot_Replacement argument of patterm form of pragma

            ---------------
            -- Get_Fname --
            ---------------

            function Get_Fname (Arg : Node_Id) return File_Name_Type is
            begin
               String_To_Name_Buffer (Strval (Expression (Arg)));

               for J in 1 .. Name_Len loop
                  if Is_Directory_Separator (Name_Buffer (J)) then
                     Error_Msg
                       ("directory separator character not allowed",
                        Sloc (Expression (Arg)) + Source_Ptr (J));
                  end if;
               end loop;

               return Name_Find;
            end Get_Fname;

            -------------------------
            -- Get_String_Argument --
            -------------------------

            function Get_String_Argument (Arg : Node_Id) return String_Ptr is
               Str : String_Id;

            begin
               if Nkind (Expression (Arg)) /= N_String_Literal
                 and then
                  Nkind (Expression (Arg)) /= N_Operator_Symbol
               then
                  Error_Msg_N
                    ("argument for pragma% must be string literal", Arg);
                  raise Error_Resync;
               end if;

               Str := Strval (Expression (Arg));

               --  Check string has no wide chars

               for J in 1 .. String_Length (Str) loop
                  if Get_String_Char (Str, J) > 255 then
                     Error_Msg
                       ("wide character not allowed in pattern for pragma%",
                        Sloc (Expression (Arg2)) + Text_Ptr (J) - 1);
                  end if;
               end loop;

               --  Acquire string

               String_To_Name_Buffer (Str);
               return new String'(Name_Buffer (1 .. Name_Len));
            end Get_String_Argument;

            --------------------
            -- Process_Casing --
            --------------------

            procedure Process_Casing (Arg : Node_Id) is
               Expr : constant Node_Id := Expression (Arg);

            begin
               Check_Required_Identifier (Arg, Name_Casing);

               if Nkind (Expr) = N_Identifier then
                  if Chars (Expr) = Name_Lowercase then
                     Cas := All_Lower_Case;
                     return;
                  elsif Chars (Expr) = Name_Uppercase then
                     Cas := All_Upper_Case;
                     return;
                  elsif Chars (Expr) = Name_Mixedcase then
                     Cas := Mixed_Case;
                     return;
                  end if;
               end if;

               Error_Msg_N
                 ("Casing argument for pragma% must be " &
                  "one of Mixedcase, Lowercase, Uppercase",
                  Arg);
            end Process_Casing;

            -----------------------------
            -- Process_Dot_Replacement --
            -----------------------------

            procedure Process_Dot_Replacement (Arg : Node_Id) is
            begin
               Check_Required_Identifier (Arg, Name_Dot_Replacement);
               Dot := Get_String_Argument (Arg);
            end Process_Dot_Replacement;

         --  Start of processing for Source_File_Name and
         --  Source_File_Name_Project pragmas.

         begin
            if Get_Pragma_Id (Pragma_Name) = Pragma_Source_File_Name then
               if Project_File_In_Use = In_Use then
                  Error_Msg
                    ("pragma Source_File_Name cannot be used " &
                     "with a project file", Pragma_Sloc);

               else
                  Project_File_In_Use := Not_In_Use;
               end if;

            else
               if Project_File_In_Use = Not_In_Use then
                  Error_Msg
                    ("pragma Source_File_Name_Project should only be used " &
                     "with a project file", Pragma_Sloc);
               else
                  Project_File_In_Use := In_Use;
               end if;
            end if;

            --  We permit from 1 to 3 arguments

            if Arg_Count not in 1 .. 3 then
               Check_Arg_Count (1);
            end if;

            Expr1 := Expression (Arg1);

            --  If first argument is identifier or selected component, then
            --  we have the specific file case of the Source_File_Name pragma,
            --  and the first argument is a unit name.

            if Nkind (Expr1) = N_Identifier
              or else
                (Nkind (Expr1) = N_Selected_Component
                  and then
                 Nkind (Selector_Name (Expr1)) = N_Identifier)
            then
               if Nkind (Expr1) = N_Identifier
                 and then Chars (Expr1) = Name_System
               then
                  Error_Msg_N
                    ("pragma Source_File_Name may not be used for System",
                     Arg1);
                  return Error;
               end if;

               --  Process index argument if present

               if Arg_Count = 3 then
                  Expr := Expression (Arg3);

                  if Nkind (Expr) /= N_Integer_Literal
                    or else not UI_Is_In_Int_Range (Intval (Expr))
                    or else Intval (Expr) > 999
                    or else Intval (Expr) <= 0
                  then
                     Error_Msg
                       ("pragma% index must be integer literal" &
                        " in range 1 .. 999", Sloc (Expr));
                     raise Error_Resync;
                  else
                     Index := UI_To_Int (Intval (Expr));
                  end if;

               --  No index argument present

               else
                  Check_Arg_Count (2);
                  Index := 0;
               end if;

               Check_Optional_Identifier (Arg1, Name_Unit_Name);
               Unam := Get_Unit_Name (Expr1);

               Check_Arg_Is_String_Literal (Arg2);

               if Chars (Arg2) = Name_Spec_File_Name then
                  Set_File_Name
                    (Get_Spec_Name (Unam), Get_Fname (Arg2), Index);

               elsif Chars (Arg2) = Name_Body_File_Name then
                  Set_File_Name
                    (Unam, Get_Fname (Arg2), Index);

               else
                  Error_Msg_N
                    ("pragma% argument has incorrect identifier", Arg2);
                  return Pragma_Node;
               end if;

            --  If the first argument is not an identifier, then we must have
            --  the pattern form of the pragma, and the first argument must be
            --  the pattern string with an appropriate name.

            else
               if Chars (Arg1) = Name_Spec_File_Name then
                  Typ := 's';

               elsif Chars (Arg1) = Name_Body_File_Name then
                  Typ := 'b';

               elsif Chars (Arg1) = Name_Subunit_File_Name then
                  Typ := 'u';

               elsif Chars (Arg1) = Name_Unit_Name then
                  Error_Msg_N
                    ("Unit_Name parameter for pragma% must be an identifier",
                     Arg1);
                  raise Error_Resync;

               else
                  Error_Msg_N
                    ("pragma% argument has incorrect identifier", Arg1);
                  raise Error_Resync;
               end if;

               Pat := Get_String_Argument (Arg1);

               --  Check pattern has exactly one asterisk

               Nast := 0;
               for J in Pat'Range loop
                  if Pat (J) = '*' then
                     Nast := Nast + 1;
                  end if;
               end loop;

               if Nast /= 1 then
                  Error_Msg_N
                    ("file name pattern must have exactly one * character",
                     Arg1);
                  return Pragma_Node;
               end if;

               --  Set defaults for Casing and Dot_Separator parameters

               Cas := All_Lower_Case;
               Dot := new String'(".");

               --  Process second and third arguments if present

               if Arg_Count > 1 then
                  if Chars (Arg2) = Name_Casing then
                     Process_Casing (Arg2);

                     if Arg_Count = 3 then
                        Process_Dot_Replacement (Arg3);
                     end if;

                  else
                     Process_Dot_Replacement (Arg2);

                     if Arg_Count = 3 then
                        Process_Casing (Arg3);
                     end if;
                  end if;
               end if;

               Set_File_Name_Pattern (Pat, Typ, Dot, Cas);
            end if;
         end Source_File_Name;

      -----------------------------
      -- Source_Reference (GNAT) --
      -----------------------------

      --  pragma Source_Reference
      --    (INTEGER_LITERAL [, STRING_LITERAL] );

      --  Processing for this pragma must be done at parse time, since error
      --  messages needing the proper line numbers can be generated in parse
      --  only mode with semantic checking turned off, and indeed we usually
      --  turn off semantic checking anyway if any parse errors are found.

      when Pragma_Source_Reference => Source_Reference : declare
         Fname : File_Name_Type;

      begin
         if Arg_Count /= 1 then
            Check_Arg_Count (2);
            Check_No_Identifier (Arg2);
         end if;

         --  Check that this is first line of file. We skip this test if
         --  we are in syntax check only mode, since we may be dealing with
         --  multiple compilation units.

         if Get_Physical_Line_Number (Pragma_Sloc) /= 1
           and then Num_SRef_Pragmas (Current_Source_File) = 0
           and then Operating_Mode /= Check_Syntax
         then
            Error_Msg
              ("first % pragma must be first line of file", Pragma_Sloc);
            raise Error_Resync;
         end if;

         Check_No_Identifier (Arg1);

         if Arg_Count = 1 then
            if Num_SRef_Pragmas (Current_Source_File) = 0 then
               Error_Msg
                 ("file name required for first % pragma in file",
                  Pragma_Sloc);
               raise Error_Resync;
            else
               Fname := No_File;
            end if;

         --  File name present

         else
            Check_Arg_Is_String_Literal (Arg2);
            String_To_Name_Buffer (Strval (Expression (Arg2)));
            Fname := Name_Find;

            if Num_SRef_Pragmas (Current_Source_File) > 0 then
               if Fname /= Full_Ref_Name (Current_Source_File) then
                  Error_Msg
                    ("file name must be same in all % pragmas", Pragma_Sloc);
                  raise Error_Resync;
               end if;
            end if;
         end if;

         if Nkind (Expression (Arg1)) /= N_Integer_Literal then
            Error_Msg
              ("argument for pragma% must be integer literal",
                Sloc (Expression (Arg1)));
            raise Error_Resync;

         --  OK, this source reference pragma is effective, however, we
         --  ignore it if it is not in the first unit in the multiple unit
         --  case. This is because the only purpose in this case is to
         --  provide source pragmas for subsequent use by gnatchop.

         else
            if Num_Library_Units = 1 then
               Register_Source_Ref_Pragma
                 (Fname,
                  Strip_Directory (Fname),
                  UI_To_Int (Intval (Expression (Arg1))),
                  Get_Physical_Line_Number (Pragma_Sloc) + 1);
            end if;
         end if;
      end Source_Reference;

      -------------------------
      -- Style_Checks (GNAT) --
      -------------------------

      --  pragma Style_Checks (On | Off | ALL_CHECKS | STRING_LITERAL);

      --  This is processed by the parser since some of the style
      --  checks take place during source scanning and parsing.

      when Pragma_Style_Checks => Style_Checks : declare
         A  : Node_Id;
         S  : String_Id;
         C  : Char_Code;
         OK : Boolean := True;

      begin
         --  Two argument case is only for semantics

         if Arg_Count = 2 then
            null;

         else
            Check_Arg_Count (1);
            Check_No_Identifier (Arg1);
            A := Expression (Arg1);

            if Nkind (A) = N_String_Literal then
               S := Strval (A);

               declare
                  Slen    : constant Natural := Natural (String_Length (S));
                  Options : String (1 .. Slen);
                  J       : Natural;
                  Ptr     : Natural;

               begin
                  J := 1;
                  loop
                     C := Get_String_Char (S, Int (J));

                     if not In_Character_Range (C) then
                        OK := False;
                        Ptr := J;
                        exit;

                     else
                        Options (J) := Get_Character (C);
                     end if;

                     if J = Slen then
                        Set_Style_Check_Options (Options, OK, Ptr);
                        exit;

                     else
                        J := J + 1;
                     end if;
                  end loop;

                  if not OK then
                     Error_Msg
                       (Style_Msg_Buf (1 .. Style_Msg_Len),
                        Sloc (Expression (Arg1)) + Source_Ptr (Ptr));
                     raise Error_Resync;
                  end if;
               end;

            elsif Nkind (A) /= N_Identifier then
               OK := False;

            elsif Chars (A) = Name_All_Checks then
               Stylesw.Set_Default_Style_Check_Options;

            elsif Chars (A) = Name_On then
               Style_Check := True;

            elsif Chars (A) = Name_Off then
               Style_Check := False;

            else
               OK := False;
            end if;

            if not OK then
               Error_Msg ("incorrect argument for pragma%", Sloc (A));
               raise Error_Resync;
            end if;
         end if;
      end Style_Checks;

      ---------------------
      -- Warnings (GNAT) --
      ---------------------

      --  pragma Warnings (On | Off);
      --  pragma Warnings (On | Off, LOCAL_NAME);
      --  pragma Warnings (static_string_EXPRESSION);
      --  pragma Warnings (On | Off, static_string_EXPRESSION);

      --  The one argument ON/OFF case is processed by the parser, since it may
      --  control parser warnings as well as semantic warnings, and in any case
      --  we want to be absolutely sure that the range in the warnings table is
      --  set well before any semantic analysis is performed.

      when Pragma_Warnings =>
         if Arg_Count = 1 then
            Check_No_Identifier (Arg1);

            declare
               Argx : constant Node_Id := Expression (Arg1);
            begin
               if Nkind (Argx) = N_Identifier then
                  if Chars (Argx) = Name_On then
                     Set_Warnings_Mode_On (Pragma_Sloc);
                  elsif Chars (Argx) = Name_Off then
                     Set_Warnings_Mode_Off (Pragma_Sloc);
                  end if;
               end if;
            end;
         end if;

      -----------------------------
      -- Wide_Character_Encoding --
      -----------------------------

      --  pragma Wide_Character_Encoding (IDENTIFIER | CHARACTER_LITERAL);

      --  This is processed by the parser, since the scanner is affected

      when Pragma_Wide_Character_Encoding => Wide_Character_Encoding : declare
         A : Node_Id;

      begin
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         A := Expression (Arg1);

         if Nkind (A) = N_Identifier then
            Get_Name_String (Chars (A));
            Wide_Character_Encoding_Method :=
              Get_WC_Encoding_Method (Name_Buffer (1 .. Name_Len));

         elsif Nkind (A) = N_Character_Literal then
            declare
               R : constant Char_Code :=
                     Char_Code (UI_To_Int (Char_Literal_Value (A)));
            begin
               if In_Character_Range (R) then
                  Wide_Character_Encoding_Method :=
                    Get_WC_Encoding_Method (Get_Character (R));
               else
                  raise Constraint_Error;
               end if;
            end;

         else
               raise Constraint_Error;
         end if;

      exception
         when Constraint_Error =>
            Error_Msg_N ("invalid argument for pragma%", Arg1);
      end Wide_Character_Encoding;

      -----------------------
      -- All Other Pragmas --
      -----------------------

      --  For all other pragmas, checking and processing is handled
      --  entirely in Sem_Prag, and no further checking is done by Par.

      when Pragma_Abort_Defer                   |
           Pragma_Assertion_Policy              |
           Pragma_AST_Entry                     |
           Pragma_All_Calls_Remote              |
           Pragma_Annotate                      |
           Pragma_Assert                        |
           Pragma_Asynchronous                  |
           Pragma_Atomic                        |
           Pragma_Atomic_Components             |
           Pragma_Attach_Handler                |
           Pragma_Check_Name                    |
           Pragma_CIL_Constructor               |
           Pragma_Compile_Time_Error            |
           Pragma_Compile_Time_Warning          |
           Pragma_Compiler_Unit                 |
           Pragma_Convention_Identifier         |
           Pragma_CPP_Class                     |
           Pragma_CPP_Constructor               |
           Pragma_CPP_Virtual                   |
           Pragma_CPP_Vtable                    |
           Pragma_C_Pass_By_Copy                |
           Pragma_Comment                       |
           Pragma_Common_Object                 |
           Pragma_Complete_Representation       |
           Pragma_Complex_Representation        |
           Pragma_Component_Alignment           |
           Pragma_Controlled                    |
           Pragma_Convention                    |
           Pragma_Debug_Policy                  |
           Pragma_Detect_Blocking               |
           Pragma_Discard_Names                 |
           Pragma_Eliminate                     |
           Pragma_Elaborate                     |
           Pragma_Elaborate_All                 |
           Pragma_Elaborate_Body                |
           Pragma_Elaboration_Checks            |
           Pragma_Export                        |
           Pragma_Export_Exception              |
           Pragma_Export_Function               |
           Pragma_Export_Object                 |
           Pragma_Export_Procedure              |
           Pragma_Export_Value                  |
           Pragma_Export_Valued_Procedure       |
           Pragma_Extend_System                 |
           Pragma_External                      |
           Pragma_External_Name_Casing          |
           Pragma_Finalize_Storage_Only         |
           Pragma_Float_Representation          |
           Pragma_Ident                         |
           Pragma_Implicit_Packing              |
           Pragma_Import                        |
           Pragma_Import_Exception              |
           Pragma_Import_Function               |
           Pragma_Import_Object                 |
           Pragma_Import_Procedure              |
           Pragma_Import_Valued_Procedure       |
           Pragma_Initialize_Scalars            |
           Pragma_Inline                        |
           Pragma_Inline_Always                 |
           Pragma_Inline_Generic                |
           Pragma_Inspection_Point              |
           Pragma_Interface                     |
           Pragma_Interface_Name                |
           Pragma_Interrupt_Handler             |
           Pragma_Interrupt_State               |
           Pragma_Interrupt_Priority            |
           Pragma_Java_Constructor              |
           Pragma_Java_Interface                |
           Pragma_Keep_Names                    |
           Pragma_License                       |
           Pragma_Link_With                     |
           Pragma_Linker_Alias                  |
           Pragma_Linker_Constructor            |
           Pragma_Linker_Destructor             |
           Pragma_Linker_Options                |
           Pragma_Linker_Section                |
           Pragma_Locking_Policy                |
           Pragma_Long_Float                    |
           Pragma_Machine_Attribute             |
           Pragma_Main                          |
           Pragma_Main_Storage                  |
           Pragma_Memory_Size                   |
           Pragma_No_Body                       |
           Pragma_No_Return                     |
           Pragma_Obsolescent                   |
           Pragma_No_Run_Time                   |
           Pragma_No_Strict_Aliasing            |
           Pragma_Normalize_Scalars             |
           Pragma_Optimize                      |
           Pragma_Pack                          |
           Pragma_Passive                       |
           Pragma_Preelaborable_Initialization  |
           Pragma_Polling                       |
           Pragma_Persistent_BSS                |
           Pragma_Preelaborate                  |
           Pragma_Preelaborate_05               |
           Pragma_Priority                      |
           Pragma_Priority_Specific_Dispatching |
           Pragma_Profile                       |
           Pragma_Profile_Warnings              |
           Pragma_Propagate_Exceptions          |
           Pragma_Psect_Object                  |
           Pragma_Pure                          |
           Pragma_Pure_05                       |
           Pragma_Pure_Function                 |
           Pragma_Queuing_Policy                |
           Pragma_Remote_Call_Interface         |
           Pragma_Remote_Types                  |
           Pragma_Restricted_Run_Time           |
           Pragma_Ravenscar                     |
           Pragma_Reviewable                    |
           Pragma_Share_Generic                 |
           Pragma_Shared                        |
           Pragma_Shared_Passive                |
           Pragma_Storage_Size                  |
           Pragma_Storage_Unit                  |
           Pragma_Static_Elaboration_Desired    |
           Pragma_Stream_Convert                |
           Pragma_Subtitle                      |
           Pragma_Suppress                      |
           Pragma_Suppress_All                  |
           Pragma_Suppress_Debug_Info           |
           Pragma_Suppress_Exception_Locations  |
           Pragma_Suppress_Initialization       |
           Pragma_System_Name                   |
           Pragma_Task_Dispatching_Policy       |
           Pragma_Task_Info                     |
           Pragma_Task_Name                     |
           Pragma_Task_Storage                  |
           Pragma_Time_Slice                    |
           Pragma_Title                         |
           Pragma_Unchecked_Union               |
           Pragma_Unimplemented_Unit            |
           Pragma_Universal_Aliasing            |
           Pragma_Universal_Data                |
           Pragma_Unreferenced                  |
           Pragma_Unreferenced_Objects          |
           Pragma_Unreserve_All_Interrupts      |
           Pragma_Unsuppress                    |
           Pragma_Use_VADS_Size                 |
           Pragma_Volatile                      |
           Pragma_Volatile_Components           |
           Pragma_Weak_External                 |
           Pragma_Validity_Checks               =>
         null;

      --------------------
      -- Unknown_Pragma --
      --------------------

      --  Should be impossible, since we excluded this case earlier on

      when Unknown_Pragma =>
         raise Program_Error;

   end case;

   return Pragma_Node;

   --------------------
   -- Error Handling --
   --------------------

exception
   when Error_Resync =>
      return Error;

end Prag;