aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/switch-c.adb
blob: 183d0efaf4fbd3715b6779f58758b104abe3c6c8 (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
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             S W I T C H - C                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2001-2018, 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.      --
--                                                                          --
------------------------------------------------------------------------------

--  This package is for switch processing and should not depend on higher level
--  packages such as those for the scanner, parser, etc. Doing so may cause
--  circularities, especially for back ends using Adabkend.

with Debug;    use Debug;
with Errout;   use Errout;
with Lib;      use Lib;
with Osint;    use Osint;
with Opt;      use Opt;
with Stylesw;  use Stylesw;
with Targparm; use Targparm;
with Ttypes;   use Ttypes;
with Validsw;  use Validsw;
with Warnsw;   use Warnsw;

with Ada.Unchecked_Deallocation;

with System.WCh_Con; use System.WCh_Con;
with System.OS_Lib;

package body Switch.C is

   RTS_Specified : String_Access := null;
   --  Used to detect multiple use of --RTS= flag

   procedure Add_Symbol_Definition (Def : String);
   --  Add a symbol definition from the command line

   procedure Free is
      new Ada.Unchecked_Deallocation (String_List, String_List_Access);
   --  Avoid using System.Strings.Free, which also frees the designated strings

   function Get_Overflow_Mode (C : Character) return Overflow_Mode_Type;
   --  Given a digit in the range 0 .. 3, returns the corresponding value of
   --  Overflow_Mode_Type. Raises Program_Error if C is outside this range.

   function Switch_Subsequently_Cancelled
     (C        : String;
      Args     : String_List;
      Arg_Rank : Positive) return Boolean;
   --  This function is called from Scan_Front_End_Switches. It determines if
   --  the switch currently being scanned is followed by a switch of the form
   --  "-gnat-" & C, where C is the argument. If so, then True is returned,
   --  and Scan_Front_End_Switches will cancel the effect of the switch. If
   --  no such switch is found, False is returned.

   ---------------------------
   -- Add_Symbol_Definition --
   ---------------------------

   procedure Add_Symbol_Definition (Def : String) is
   begin
      --  If Preprocessor_Symbol_Defs is not large enough, double its size

      if Preprocessing_Symbol_Last = Preprocessing_Symbol_Defs'Last then
         declare
            New_Symbol_Definitions : constant String_List_Access :=
              new String_List (1 .. 2 * Preprocessing_Symbol_Last);
         begin
            New_Symbol_Definitions (Preprocessing_Symbol_Defs'Range) :=
              Preprocessing_Symbol_Defs.all;
            Free (Preprocessing_Symbol_Defs);
            Preprocessing_Symbol_Defs := New_Symbol_Definitions;
         end;
      end if;

      Preprocessing_Symbol_Last := Preprocessing_Symbol_Last + 1;
      Preprocessing_Symbol_Defs (Preprocessing_Symbol_Last) :=
        new String'(Def);
   end Add_Symbol_Definition;

   -----------------------
   -- Get_Overflow_Mode --
   -----------------------

   function Get_Overflow_Mode (C : Character) return Overflow_Mode_Type is
   begin
      case C is
         when '1' =>
            return Strict;

         when '2' =>
            return Minimized;

         --  Eliminated allowed only if Long_Long_Integer is 64 bits (since
         --  the current implementation of System.Bignums assumes this).

         when '3' =>
            if Standard_Long_Long_Integer_Size /= 64 then
               Bad_Switch ("-gnato3 not implemented for this configuration");
            else
               return Eliminated;
            end if;

         when others =>
            raise Program_Error;
      end case;
   end Get_Overflow_Mode;

   -----------------------------
   -- Scan_Front_End_Switches --
   -----------------------------

   procedure Scan_Front_End_Switches
     (Switch_Chars : String;
      Args         : String_List;
      Arg_Rank     : Positive)
   is
      Max : constant Natural := Switch_Chars'Last;
      C   : Character := ' ';
      Ptr : Natural;

      Dot : Boolean;
      --  This flag is set upon encountering a dot in a debug switch

      First_Char : Positive;
      --  Marks start of switch to be stored

      First_Ptr : Positive;
      --  Save position of first character after -gnatd (for checking that
      --  debug flags that must come first are first, in particular -gnatd.b).

      First_Switch : Boolean := True;
      --  False for all but first switch

      Store_Switch : Boolean;
      --  For -gnatxx switches, the normal processing, signalled by this flag
      --  being set to True, is to store the switch on exit from the case
      --  statement, the switch stored is -gnat followed by the characters
      --  from First_Char to Ptr-1. For cases like -gnaty, where the switch
      --  is stored in separate pieces, this flag is set to False, and the
      --  appropriate calls to Store_Compilation_Switch are made from within
      --  the case branch.

      Underscore : Boolean;
      --  This flag is set upon encountering an underscode in a debug switch

   begin
      Ptr := Switch_Chars'First;

      --  Skip past the initial character (must be the switch character)

      if Ptr = Max then
         Bad_Switch (C);
      else
         Ptr := Ptr + 1;
      end if;

      --  Handle switches that do not start with -gnat

      if Ptr + 3 > Max or else Switch_Chars (Ptr .. Ptr + 3) /= "gnat" then

         --  There are two front-end switches that do not start with -gnat:
         --  -I, --RTS

         if Switch_Chars (Ptr) = 'I' then

            --  Set flag Search_Directory_Present if switch is "-I" only:
            --  the directory will be the next argument.

            if Ptr = Max then
               Search_Directory_Present := True;
               return;
            end if;

            Ptr := Ptr + 1;

            --  Find out whether this is a -I- or regular -Ixxx switch

            --  Note: -I switches are not recorded in the ALI file, since the
            --  meaning of the program depends on the source files compiled,
            --  not where they came from.

            if Ptr = Max and then Switch_Chars (Ptr) = '-' then
               Look_In_Primary_Dir := False;
            else
               Add_Src_Search_Dir (Switch_Chars (Ptr .. Max));
            end if;

         --  Processing of the --RTS switch. --RTS may have been modified by
         --  gcc into -fRTS (for GCC targets).

         elsif Ptr + 3 <= Max
           and then (Switch_Chars (Ptr .. Ptr + 3) = "fRTS"
                       or else
                     Switch_Chars (Ptr .. Ptr + 3) = "-RTS")
         then
            Ptr := Ptr + 1;

            if Ptr + 4 > Max
              or else Switch_Chars (Ptr + 3) /= '='
            then
               Osint.Fail ("missing path for --RTS");

            else
               declare
                  Runtime_Dir : String_Access;
               begin
                  if System.OS_Lib.Is_Absolute_Path
                       (Switch_Chars (Ptr + 4 .. Max))
                  then
                     Runtime_Dir :=
                       new String'(System.OS_Lib.Normalize_Pathname
                                      (Switch_Chars (Ptr + 4 .. Max)));
                  else
                     Runtime_Dir :=
                       new String'(Switch_Chars (Ptr + 4 .. Max));
                  end if;

                  --  Valid --RTS switch

                  Opt.No_Stdinc := True;
                  Opt.RTS_Switch := True;

                  RTS_Src_Path_Name :=
                    Get_RTS_Search_Dir (Runtime_Dir.all, Include);

                  RTS_Lib_Path_Name :=
                    Get_RTS_Search_Dir (Runtime_Dir.all, Objects);

                  if RTS_Specified /= null then
                     if RTS_Src_Path_Name = null
                       or else RTS_Lib_Path_Name = null
                       or else
                         System.OS_Lib.Normalize_Pathname
                           (RTS_Specified.all) /=
                         System.OS_Lib.Normalize_Pathname
                           (RTS_Lib_Path_Name.all)
                     then
                        Osint.Fail
                          ("--RTS cannot be specified multiple times");
                     end if;

                  elsif RTS_Src_Path_Name /= null
                    and then RTS_Lib_Path_Name /= null
                  then
                     --  Store the -fRTS switch (Note: Store_Compilation_Switch
                     --  changes -fRTS back into --RTS for the actual output).

                     Store_Compilation_Switch (Switch_Chars);
                     RTS_Specified := new String'(RTS_Lib_Path_Name.all);

                  elsif RTS_Src_Path_Name = null
                    and then RTS_Lib_Path_Name = null
                  then
                     Osint.Fail ("RTS path not valid: missing "
                                 & "adainclude and adalib directories");

                  elsif RTS_Src_Path_Name = null then
                     Osint.Fail ("RTS path not valid: missing "
                                 & "adainclude directory");

                  elsif RTS_Lib_Path_Name = null then
                     Osint.Fail ("RTS path not valid: missing "
                                 & "adalib directory");
                  end if;
               end;
            end if;

            --  There are no other switches not starting with -gnat

         else
            Bad_Switch (Switch_Chars);
         end if;

      --  Case of switch starting with -gnat

      else
         Ptr := Ptr + 4;

         --  Loop to scan through switches given in switch string

         while Ptr <= Max loop
            First_Char := Ptr;
            Store_Switch := True;

            C := Switch_Chars (Ptr);

            case C is

            --  -gnata (assertions enabled)

            when 'a' =>
               Ptr := Ptr + 1;
               Assertions_Enabled := True;

            --  -gnatA (disregard gnat.adc)

            when 'A' =>
               Ptr := Ptr + 1;
               Config_File := False;

            --  -gnatb (brief messages to stderr)

            when 'b' =>
               Ptr := Ptr + 1;
               Brief_Output := True;

            --  -gnatB (assume no invalid values)

            when 'B' =>
               Ptr := Ptr + 1;
               Assume_No_Invalid_Values := True;

            --  -gnatc (check syntax and semantics only)

            when 'c' =>
               if not First_Switch then
                  Osint.Fail
                    ("-gnatc must be first if combined with other switches");
               end if;

               Ptr := Ptr + 1;
               Operating_Mode := Check_Semantics;

            --  -gnatC (Generate CodePeer information)

            when 'C' =>
               Ptr := Ptr + 1;
               CodePeer_Mode := True;

            --  -gnatd (compiler debug options)

            when 'd' =>
               Dot          := False;
               Store_Switch := False;
               Underscore   := False;

               First_Ptr := Ptr + 1;

               --  Note: for the debug switch, the remaining characters in this
               --  switch field must all be debug flags, since all valid switch
               --  characters are also valid debug characters.

               --  Loop to scan out debug flags

               while Ptr < Max loop
                  Ptr := Ptr + 1;
                  C := Switch_Chars (Ptr);
                  exit when C = ASCII.NUL or else C = '/' or else C = '-';

                  if C in '1' .. '9' or else
                     C in 'a' .. 'z' or else
                     C in 'A' .. 'Z'
                  then
                     --  Case of dotted flag

                     if Dot then
                        Set_Dotted_Debug_Flag (C);
                        Store_Compilation_Switch ("-gnatd." & C);

                        --  Special check, -gnatd.b must come first

                        if C = 'b'
                          and then (Ptr /= First_Ptr + 1
                                     or else not First_Switch)
                        then
                           Osint.Fail
                             ("-gnatd.b must be first if combined with other "
                              & "switches");
                        end if;

                     --  Case of an underscored flag

                     elsif Underscore then
                        Set_Underscored_Debug_Flag (C);
                        Store_Compilation_Switch ("-gnatd_" & C);

                     --  Normal flag

                     else
                        Set_Debug_Flag (C);
                        Store_Compilation_Switch ("-gnatd" & C);
                     end if;

                  elsif C = '.' then
                     Dot := True;

                  elsif C = '_' then
                     Underscore := True;

                  elsif Dot then
                     Bad_Switch ("-gnatd." & Switch_Chars (Ptr .. Max));

                  elsif Underscore then
                     Bad_Switch ("-gnatd_" & Switch_Chars (Ptr .. Max));

                  else
                     Bad_Switch ("-gnatd" & Switch_Chars (Ptr .. Max));
                  end if;
               end loop;

               return;

            --  -gnatD (debug expanded code)

            when 'D' =>
               Ptr := Ptr + 1;

               --  Not allowed if previous -gnatR given

               --  The reason for this prohibition is that the rewriting of
               --  Sloc values causes strange malfunctions in the tests of
               --  whether units belong to the main source. This is really a
               --  bug, but too hard to fix for a marginal capability ???

               --  The proper fix is to completely redo -gnatD processing so
               --  that the tree is not messed with, and instead a separate
               --  table is built on the side for debug information generation.

               if List_Representation_Info /= 0 then
                  Osint.Fail
                    ("-gnatD not permitted since -gnatR given previously");
               end if;

               --  Scan optional integer line limit value

               if Nat_Present (Switch_Chars, Max, Ptr) then
                  Scan_Nat (Switch_Chars, Max, Ptr, Sprint_Line_Limit, 'D');
                  Sprint_Line_Limit := Nat'Max (Sprint_Line_Limit, 40);
               end if;

               --  Note: -gnatD also sets -gnatx (to turn off cross-reference
               --  generation in the ali file) since otherwise this generation
               --  gets confused by the "wrong" Sloc values put in the tree.

               Debug_Generated_Code := True;
               Xref_Active := False;
               Set_Debug_Flag ('g');

            --  -gnate? (extended switches)

            when 'e' =>
               Ptr := Ptr + 1;

               --  The -gnate? switches are all double character switches
               --  so we must always have a character after the e.

               if Ptr > Max then
                  Bad_Switch ("-gnate");
               end if;

               case Switch_Chars (Ptr) is

                  --  -gnatea (initial delimiter of explicit switches)

                  --  This is an internal switch

                  --  All switches that come before -gnatea have been added by
                  --  the GCC driver and are not stored in the ALI file.
                  --  See also -gnatez below.

                  when 'a' =>
                     Store_Switch := False;
                     Enable_Switch_Storing;
                     Ptr := Ptr + 1;

                  --  -gnateA (aliasing checks on parameters)

                  when 'A' =>
                     Ptr := Ptr + 1;
                     Check_Aliasing_Of_Parameters := True;

                  --  -gnatec (configuration pragmas)

                  when 'c' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;

                     --  There may be an equal sign between -gnatec and
                     --  the path name of the config file.

                     if Ptr <= Max and then Switch_Chars (Ptr) = '=' then
                        Ptr := Ptr + 1;
                     end if;

                     if Ptr > Max then
                        Bad_Switch ("-gnatec");
                     end if;

                     declare
                        Config_File_Name : constant String_Access :=
                                             new String'
                                                  (Switch_Chars (Ptr .. Max));

                     begin
                        if Config_File_Names = null then
                           Config_File_Names :=
                             new String_List'(1 => Config_File_Name);

                        else
                           declare
                              New_Names : constant String_List_Access :=
                                            new String_List
                                              (1 ..
                                               Config_File_Names'Length + 1);

                           begin
                              for Index in Config_File_Names'Range loop
                                 New_Names (Index) :=
                                   Config_File_Names (Index);
                                 Config_File_Names (Index) := null;
                              end loop;

                              New_Names (New_Names'Last) := Config_File_Name;
                              Free (Config_File_Names);
                              Config_File_Names := New_Names;
                           end;
                        end if;
                     end;

                     return;

                  --  -gnateC switch (generate CodePeer messages)

                  when 'C' =>
                     Ptr := Ptr + 1;

                     if not Generate_CodePeer_Messages then
                        Generate_CodePeer_Messages := True;
                        CodePeer_Mode              := True;
                        Warning_Mode               := Normal;
                        Warning_Doc_Switch         := True;  -- -gnatw.d

                        --  Enable warnings potentially useful for non GNAT
                        --  users.

                        Constant_Condition_Warnings      := True; -- -gnatwc
                        Warn_On_Assertion_Failure        := True; -- -gnatw.a
                        Warn_On_Assumed_Low_Bound        := True; -- -gnatww
                        Warn_On_Bad_Fixed_Value          := True; -- -gnatwb
                        Warn_On_Biased_Representation    := True; -- -gnatw.b
                        Warn_On_Export_Import            := True; -- -gnatwx
                        Warn_On_No_Value_Assigned        := True; -- -gnatwv
                        Warn_On_Object_Renames_Function  := True; -- -gnatw.r
                        Warn_On_Overlap                  := True; -- -gnatw.i
                        Warn_On_Parameter_Order          := True; -- -gnatw.p
                        Warn_On_Questionable_Missing_Parens := True; -- -gnatwq
                        Warn_On_Redundant_Constructs     := True; -- -gnatwr
                        Warn_On_Suspicious_Modulus_Value := True; -- -gnatw.m
                     end if;

                  --  -gnated switch (disable atomic synchronization)

                  when 'd' =>
                     Suppress_Options.Suppress (Atomic_Synchronization) :=
                       True;

                  --  -gnateD switch (preprocessing symbol definition)

                  when 'D' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;

                     if Ptr > Max then
                        Bad_Switch ("-gnateD");
                     end if;

                     Add_Symbol_Definition (Switch_Chars (Ptr .. Max));

                     --  Store the switch

                     Store_Compilation_Switch
                       ("-gnateD" & Switch_Chars (Ptr .. Max));
                     Ptr := Max + 1;

                  --  -gnateE (extra exception information)

                  when 'E' =>
                     Exception_Extra_Info := True;
                     Ptr := Ptr + 1;

                  --  -gnatef (full source path for brief error messages)

                  when 'f' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;
                     Full_Path_Name_For_Brief_Errors := True;

                  --  -gnateF (Check_Float_Overflow)

                  when 'F' =>
                     Ptr := Ptr + 1;
                     Check_Float_Overflow := not Machine_Overflows_On_Target;

                  --  -gnateg (generate C code)

                  when 'g' =>
                     --  Special check, -gnateg must occur after -gnatc

                     if Operating_Mode /= Check_Semantics then
                        Osint.Fail
                          ("gnateg requires previous occurrence of -gnatc");
                     end if;

                     Generate_C_Code := True;
                     Ptr := Ptr + 1;

                  --  -gnateG (save preprocessor output)

                  when 'G' =>
                     Generate_Processed_File := True;
                     Ptr := Ptr + 1;

                  --  -gnatei (max number of instantiations)

                  when 'i' =>
                     Ptr := Ptr + 1;
                     Scan_Pos
                       (Switch_Chars, Max, Ptr, Maximum_Instantiations, C);

                  --  -gnateI (index of unit in multi-unit source)

                  when 'I' =>
                     Ptr := Ptr + 1;
                     Scan_Pos (Switch_Chars, Max, Ptr, Multiple_Unit_Index, C);

                  --  -gnatel

                  when 'l' =>
                     Ptr := Ptr + 1;
                     Elab_Info_Messages := True;

                  --  -gnateL

                  when 'L' =>
                     Ptr := Ptr + 1;
                     Elab_Info_Messages := False;

                  --  -gnatem (mapping file)

                  when 'm' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;

                     --  There may be an equal sign between -gnatem and
                     --  the path name of the mapping file.

                     if Ptr <= Max and then Switch_Chars (Ptr) = '=' then
                        Ptr := Ptr + 1;
                     end if;

                     if Ptr > Max then
                        Bad_Switch ("-gnatem");
                     end if;

                     Mapping_File_Name :=
                       new String'(Switch_Chars (Ptr .. Max));
                     return;

                  --  -gnateO= (object path file)

                  --  This is an internal switch

                  when 'O' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;

                     --  Check for '='

                     if Ptr >= Max or else Switch_Chars (Ptr) /= '=' then
                        Bad_Switch ("-gnateO");
                     else
                        Object_Path_File_Name :=
                          new String'(Switch_Chars (Ptr + 1 .. Max));
                     end if;

                     return;

                  --  -gnatep (preprocessing data file)

                  when 'p' =>
                     Store_Switch := False;
                     Ptr := Ptr + 1;

                     --  There may be an equal sign between -gnatep and
                     --  the path name of the mapping file.

                     if Ptr <= Max and then Switch_Chars (Ptr) = '=' then
                        Ptr := Ptr + 1;
                     end if;

                     if Ptr > Max then
                        Bad_Switch ("-gnatep");
                     end if;

                     Preprocessing_Data_File :=
                       new String'(Switch_Chars (Ptr .. Max));

                     --  Store the switch, normalizing to -gnatep=

                     Store_Compilation_Switch
                       ("-gnatep=" & Preprocessing_Data_File.all);

                     Ptr := Max + 1;

                  --  -gnateP (Treat pragma Pure/Preelaborate errs as warnings)

                  when 'P' =>
                     Treat_Categorization_Errors_As_Warnings := True;

                  --  -gnates=file (specify extra file switches for gnat2why)

                  --  This is an internal switch

                  when 's' =>
                     if not First_Switch then
                        Osint.Fail
                          ("-gnates must not be combined with other switches");
                     end if;

                     --  Check for '='

                     Ptr := Ptr + 1;

                     if Ptr >= Max or else Switch_Chars (Ptr) /= '=' then
                        Bad_Switch ("-gnates");
                     else
                        SPARK_Switches_File_Name :=
                          new String'(Switch_Chars (Ptr + 1 .. Max));
                     end if;

                     return;

                  --  -gnateS (generate SCO information)

                  --  Include Source Coverage Obligation information in ALI
                  --  files for use by source coverage analysis tools
                  --  (gnatcov) (equivalent to -fdump-scos, provided for
                  --  backwards compatibility).

                  when 'S' =>
                     Generate_SCO := True;
                     Generate_SCO_Instance_Table := True;
                     Ptr := Ptr + 1;

                  --  -gnatet (write target dependent information)

                  when 't' =>
                     if not First_Switch then
                        Osint.Fail
                          ("-gnatet must not be combined with other switches");
                     end if;

                     --  Check for '='

                     Ptr := Ptr + 1;

                     if Ptr >= Max or else Switch_Chars (Ptr) /= '=' then
                        Bad_Switch ("-gnatet");
                     else
                        Target_Dependent_Info_Write_Name :=
                          new String'(Switch_Chars (Ptr + 1 .. Max));
                     end if;

                     return;

                  --  -gnateT (read target dependent information)

                  when 'T' =>
                     if not First_Switch then
                        Osint.Fail
                          ("-gnateT must not be combined with other switches");
                     end if;

                     --  Check for '='

                     Ptr := Ptr + 1;

                     if Ptr >= Max or else Switch_Chars (Ptr) /= '=' then
                        Bad_Switch ("-gnateT");
                     else
                        --  This parameter was stored by Set_Targ earlier

                        pragma Assert
                          (Target_Dependent_Info_Read_Name.all =
                             Switch_Chars (Ptr + 1 .. Max));
                        null;
                     end if;

                     return;

                  --  -gnateu (unrecognized y,V,w switches)

                  when 'u' =>
                     Ptr := Ptr + 1;
                     Ignore_Unrecognized_VWY_Switches := True;

                  --  -gnateV (validity checks on parameters)

                  when 'V' =>
                     Ptr := Ptr + 1;
                     Check_Validity_Of_Parameters := True;

                  --  -gnateY (ignore Style_Checks pragmas)

                  when 'Y' =>
                     Ignore_Style_Checks_Pragmas := True;
                     Ptr := Ptr + 1;

                  --  -gnatez (final delimiter of explicit switches)

                  --  This is an internal switch

                  --  All switches that come after -gnatez have been added by
                  --  the GCC driver and are not stored in the ALI file. See
                  --  also -gnatea above.

                  when 'z' =>
                     Store_Switch := False;
                     Disable_Switch_Storing;
                     Ptr := Ptr + 1;

                  --  All other -gnate? switches are unassigned

                  when others =>
                     Bad_Switch ("-gnate" & Switch_Chars (Ptr .. Max));
               end case;

            --  -gnatE (dynamic elaboration checks)

            when 'E' =>
               Ptr := Ptr + 1;
               Dynamic_Elaboration_Checks := True;

            --  -gnatf (full error messages)

            when 'f' =>
               Ptr := Ptr + 1;
               All_Errors_Mode := True;

            --  -gnatF (overflow of predefined float types)

            when 'F' =>
               Ptr := Ptr + 1;
               External_Name_Exp_Casing := Uppercase;
               External_Name_Imp_Casing := Uppercase;

            --  -gnatg (GNAT implementation mode)

            when 'g' =>
               Ptr := Ptr + 1;
               GNAT_Mode := True;
               GNAT_Mode_Config := True;
               Identifier_Character_Set := 'n';
               System_Extend_Unit := Empty;
               Warning_Mode := Treat_As_Error;
               Style_Check_Main := True;
               Ada_Version          := Ada_2012;
               Ada_Version_Explicit := Ada_2012;
               Ada_Version_Pragma   := Empty;

               --  Set default warnings and style checks for -gnatg

               Set_GNAT_Mode_Warnings;
               Set_GNAT_Style_Check_Options;

            --  -gnatG (output generated code)

            when 'G' =>
               Ptr := Ptr + 1;
               Print_Generated_Code := True;

               --  Scan optional integer line limit value

               if Nat_Present (Switch_Chars, Max, Ptr) then
                  Scan_Nat (Switch_Chars, Max, Ptr, Sprint_Line_Limit, 'G');
                  Sprint_Line_Limit := Nat'Max (Sprint_Line_Limit, 40);
               end if;

            --  -gnath (help information)

            when 'h' =>
               Ptr := Ptr + 1;
               Usage_Requested := True;

            --  -gnatH (legacy static elaboration checking mode enabled)

            when 'H' =>
               Ptr := Ptr + 1;
               Legacy_Elaboration_Checks := True;

            --  -gnati (character set)

            when 'i' =>
               if Ptr = Max then
                  Bad_Switch ("-gnati");
               end if;

               Ptr := Ptr + 1;
               C := Switch_Chars (Ptr);

               if C in '1' .. '5'
                 or else C = '8'
                 or else C = '9'
                 or else C = 'p'
                 or else C = 'f'
                 or else C = 'n'
                 or else C = 'w'
               then
                  Identifier_Character_Set := C;
                  Ptr := Ptr + 1;

               else
                  Bad_Switch ("-gnati" & Switch_Chars (Ptr .. Max));
               end if;

            --  -gnatI (ignore representation clauses)

            when 'I' =>
               Ptr := Ptr + 1;
               Ignore_Rep_Clauses := True;

            --  -gnatj (messages in limited length lines)

            when 'j' =>
               Ptr := Ptr + 1;
               Scan_Nat (Switch_Chars, Max, Ptr, Error_Msg_Line_Length, C);

            --  -gnatJ (relaxed elaboration checking mode enabled)

            when 'J' =>
               Ptr := Ptr + 1;
               Relaxed_Elaboration_Checks := True;

               --  Common relaxations for both ABE mechanisms
               --
               --    -gnatd.G (ignore calls through generic formal parameters
               --              for elaboration)
               --    -gnatd.U (ignore indirect calls for static elaboration)
               --    -gnatd.y (disable implicit pragma Elaborate_All on task
               --              bodies)

               Debug_Flag_Dot_GG := True;
               Debug_Flag_Dot_UU := True;
               Debug_Flag_Dot_Y  := True;

               --  Relaxatons to the legacy ABE mechanism

               if Legacy_Elaboration_Checks then
                  null;

               --  Relaxations to the default ABE mechanism
               --
               --    -gnatd_a (stop elaboration checks on accept or select
               --              statement)
               --    -gnatd_e (ignore entry calls and requeue statements for
               --              elaboration)
               --    -gnatd_i (ignore activations and calls to instances for
               --              elaboration)
               --    -gnatd_p (ignore assertion pragmas for elaboration)
               --    -gnatd_s (stop elaboration checks on synchronous
               --              suspension)
               --    -gnatdL  (ignore external calls from instances for
               --              elaboration)

               else
                  Debug_Flag_Underscore_A := True;
                  Debug_Flag_Underscore_E := True;
                  Debug_Flag_Underscore_I := True;
                  Debug_Flag_Underscore_P := True;
                  Debug_Flag_Underscore_S := True;
                  Debug_Flag_LL           := True;
               end if;

            --  -gnatk (limit file name length)

            when 'k' =>
               Ptr := Ptr + 1;
                  Scan_Pos
                    (Switch_Chars, Max, Ptr, Maximum_File_Name_Length, C);

            --  -gnatl (output full source)

            when 'l' =>
               Ptr := Ptr + 1;
               Full_List := True;

               --  There may be an equal sign between -gnatl and a file name

               if Ptr <= Max and then Switch_Chars (Ptr) = '=' then
                  if Ptr = Max then
                     Osint.Fail ("file name for -gnatl= is null");
                  else
                     Opt.Full_List_File_Name :=
                       new String'(Switch_Chars (Ptr + 1 .. Max));
                     Ptr := Max + 1;
                  end if;
               end if;

            --  -gnatL (corresponding source text)

            when 'L' =>
               Ptr := Ptr + 1;
               Dump_Source_Text := True;

            --  -gnatm (max number or errors/warnings)

            when 'm' =>
               Ptr := Ptr + 1;
               Scan_Nat (Switch_Chars, Max, Ptr, Maximum_Messages, C);

            --  -gnatn (enable pragma Inline)

            when 'n' =>
               Ptr := Ptr + 1;
               Inline_Active := True;

               --  There may be a digit (1 or 2) appended to the switch

               if Ptr <= Max then
                  C := Switch_Chars (Ptr);

                  if C in '1' .. '2' then
                     Ptr := Ptr + 1;
                     Inline_Level := Character'Pos (C) - Character'Pos ('0');
                  end if;
               end if;

            --  -gnatN (obsolescent)

            when 'N' =>
               Ptr := Ptr + 1;
               Inline_Active := True;
               Front_End_Inlining := True;

            --  -gnato (overflow checks)

            when 'o' =>
               Ptr := Ptr + 1;

               --  Case of -gnato0 (overflow checking turned off)

               if Ptr <= Max and then Switch_Chars (Ptr) = '0' then
                  Ptr := Ptr + 1;
                  Suppress_Options.Suppress (Overflow_Check) := True;

                  --  We set strict mode in case overflow checking is turned
                  --  on locally (also records that we had a -gnato switch).

                  Suppress_Options.Overflow_Mode_General    := Strict;
                  Suppress_Options.Overflow_Mode_Assertions := Strict;

               --  All cases other than -gnato0 (overflow checking turned on)

               else
                  Suppress_Options.Suppress (Overflow_Check) := False;

                  --  Case of no digits after the -gnato

                  if Ptr > Max
                    or else Switch_Chars (Ptr) not in '1' .. '3'
                  then
                     Suppress_Options.Overflow_Mode_General    := Strict;
                     Suppress_Options.Overflow_Mode_Assertions := Strict;

                  --  At least one digit after the -gnato

                  else
                     --  Handle first digit after -gnato

                     Suppress_Options.Overflow_Mode_General :=
                       Get_Overflow_Mode (Switch_Chars (Ptr));
                     Ptr := Ptr + 1;

                     --  Only one digit after -gnato, set assertions mode to be
                     --  the same as general mode.

                     if Ptr > Max
                       or else Switch_Chars (Ptr) not in '1' .. '3'
                     then
                        Suppress_Options.Overflow_Mode_Assertions :=
                          Suppress_Options.Overflow_Mode_General;

                     --  Process second digit after -gnato

                     else
                        Suppress_Options.Overflow_Mode_Assertions :=
                          Get_Overflow_Mode (Switch_Chars (Ptr));
                        Ptr := Ptr + 1;
                     end if;
                  end if;
               end if;

            --  -gnatO (specify name of the object file)

            --  This is an internal switch

            when 'O' =>
               Store_Switch := False;
               Ptr := Ptr + 1;
               Output_File_Name_Present := True;

            --  -gnatp (suppress all checks)

            when 'p' =>
               Ptr := Ptr + 1;

               --  Skip processing if cancelled by subsequent -gnat-p

               if Switch_Subsequently_Cancelled ("p", Args, Arg_Rank) then
                  Store_Switch := False;

               else
                  --  Set all specific options as well as All_Checks in the
                  --  Suppress_Options array, excluding Elaboration_Check,
                  --  since this is treated specially because we do not want
                  --  -gnatp to disable static elaboration processing. Also
                  --  exclude Atomic_Synchronization, since this is not a real
                  --  check.

                  for J in Suppress_Options.Suppress'Range loop
                     if J /= Elaboration_Check
                          and then
                        J /= Atomic_Synchronization
                     then
                        Suppress_Options.Suppress (J) := True;
                     end if;
                  end loop;

                  Validity_Checks_On  := False;
                  Opt.Suppress_Checks := True;

                  --  Set overflow mode checking to strict in case it gets
                  --  turned on locally (also signals that overflow checking
                  --  has been specifically turned off).

                  Suppress_Options.Overflow_Mode_General    := Strict;
                  Suppress_Options.Overflow_Mode_Assertions := Strict;
               end if;

            --  -gnatP (periodic poll)

            when 'P' =>
               Ptr := Ptr + 1;
               Polling_Required := True;

            --  -gnatq (don't quit)

            when 'q' =>
               Ptr := Ptr + 1;
               Try_Semantics := True;

            --  -gnatQ (always write ALI file)

            when 'Q' =>
               Ptr := Ptr + 1;
               Force_ALI_Tree_File := True;
               Try_Semantics := True;

            --  -gnatr (restrictions as warnings)

            when 'r' =>
               Ptr := Ptr + 1;
               Treat_Restrictions_As_Warnings := True;

            --  -gnatR (list rep. info)

            when 'R' =>

               --  Not allowed if previous -gnatD given. See more extensive
               --  comments in the 'D' section for the inverse test.

               if Debug_Generated_Code then
                  Osint.Fail
                    ("-gnatR not permitted since -gnatD given previously");
               end if;

               --  Set to annotate rep info, and set default -gnatR mode

               Back_Annotate_Rep_Info := True;
               List_Representation_Info := 1;

               --  Scan possible parameter

               Ptr := Ptr + 1;
               while Ptr <= Max loop
                  C := Switch_Chars (Ptr);

                  case C is

                  when '0' .. '3' =>
                     List_Representation_Info :=
                       Character'Pos (C) - Character'Pos ('0');

                  when 's' =>
                     List_Representation_Info_To_File := True;

                  when 'm' =>
                     List_Representation_Info_Mechanisms := True;

                  when 'e' =>
                     List_Representation_Info_Extended := True;

                  when others =>
                     Bad_Switch ("-gnatR" & Switch_Chars (Ptr .. Max));
                  end case;

                  Ptr := Ptr + 1;
               end loop;

            --  -gnats (syntax check only)

            when 's' =>
               if not First_Switch then
                  Osint.Fail
                    ("-gnats must be first if combined with other switches");
               end if;

               Ptr := Ptr + 1;
               Operating_Mode := Check_Syntax;

            --  -gnatS (print package Standard)

            when 'S' =>
               Print_Standard := True;
               Ptr := Ptr + 1;

            --  -gnatt (output tree)

            when 't' =>
               Ptr := Ptr + 1;
               Tree_Output := True;
               Back_Annotate_Rep_Info := True;

            --  -gnatT (change start of internal table sizes)

            when 'T' =>
               Ptr := Ptr + 1;
               Scan_Pos (Switch_Chars, Max, Ptr, Table_Factor, C);

            --  -gnatu (list units for compilation)

            when 'u' =>
               Ptr := Ptr + 1;
               List_Units := True;

            --  -gnatU (unique tags)

            when 'U' =>
               Ptr := Ptr + 1;
               Unique_Error_Tag := True;

            --  -gnatv (verbose mode)

            when 'v' =>
               Ptr := Ptr + 1;
               Verbose_Mode := True;

            --  -gnatV (validity checks)

            when 'V' =>
               Store_Switch := False;
               Ptr := Ptr + 1;

               if Ptr > Max then
                  Bad_Switch ("-gnatV");

               else
                  declare
                     OK  : Boolean;

                  begin
                     Set_Validity_Check_Options
                       (Switch_Chars (Ptr .. Max), OK, Ptr);

                     if not OK then
                        Bad_Switch ("-gnatV" & Switch_Chars (Ptr .. Max));
                     end if;

                     for Index in First_Char + 1 .. Max loop
                        Store_Compilation_Switch
                          ("-gnatV" & Switch_Chars (Index));
                     end loop;
                  end;
               end if;

               Ptr := Max + 1;

            --  -gnatw (warning modes)

            when 'w' =>
               Store_Switch := False;
               Ptr := Ptr + 1;

               if Ptr > Max then
                  Bad_Switch ("-gnatw");
               end if;

               while Ptr <= Max loop
                  C := Switch_Chars (Ptr);

                  --  Case of dot switch

                  if C = '.' and then Ptr < Max then
                     Ptr := Ptr + 1;
                     C := Switch_Chars (Ptr);

                     if Set_Dot_Warning_Switch (C) then
                        Store_Compilation_Switch ("-gnatw." & C);
                     else
                        Bad_Switch ("-gnatw." & Switch_Chars (Ptr .. Max));
                     end if;

                  --  Case of underscore switch

                  elsif C = '_' and then Ptr < Max then
                     Ptr := Ptr + 1;
                     C := Switch_Chars (Ptr);

                     if Set_Underscore_Warning_Switch (C) then
                        Store_Compilation_Switch ("-gnatw_" & C);
                     else
                        Bad_Switch ("-gnatw_" & Switch_Chars (Ptr .. Max));
                     end if;

                  --  Normal case

                  else
                     if Set_Warning_Switch (C) then
                        Store_Compilation_Switch ("-gnatw" & C);
                     else
                        Bad_Switch ("-gnatw" & Switch_Chars (Ptr .. Max));
                     end if;
                  end if;

                  Ptr := Ptr + 1;
               end loop;

               return;

            --  -gnatW (wide character encoding method)

            when 'W' =>
               Ptr := Ptr + 1;

               if Ptr > Max then
                  Bad_Switch ("-gnatW");
               end if;

               begin
                  Wide_Character_Encoding_Method :=
                    Get_WC_Encoding_Method (Switch_Chars (Ptr));
               exception
                  when Constraint_Error =>
                     Bad_Switch ("-gnatW" & Switch_Chars (Ptr .. Max));
               end;

               Wide_Character_Encoding_Method_Specified := True;

               Upper_Half_Encoding :=
                 Wide_Character_Encoding_Method in
                   WC_Upper_Half_Encoding_Method;

               Ptr := Ptr + 1;

            --  -gnatx (suppress cross-ref information)

            when 'x' =>
               Ptr := Ptr + 1;
               Xref_Active := False;

            --  -gnatX (language extensions)

            when 'X' =>
               Ptr := Ptr + 1;
               Extensions_Allowed   := True;
               Ada_Version          := Ada_Version_Type'Last;
               Ada_Version_Explicit := Ada_Version_Type'Last;
               Ada_Version_Pragma   := Empty;

            --  -gnaty (style checks)

            when 'y' =>
               Ptr := Ptr + 1;
               Style_Check_Main := True;

               if Ptr > Max then
                  Set_Default_Style_Check_Options;

               else
                  Store_Switch := False;

                  declare
                     OK  : Boolean;

                  begin
                     Set_Style_Check_Options
                       (Switch_Chars (Ptr .. Max), OK, Ptr);

                     if not OK then
                        Osint.Fail
                          ("bad -gnaty switch (" &
                           Style_Msg_Buf (1 .. Style_Msg_Len) & ')');
                     end if;

                     Ptr := First_Char + 1;
                     while Ptr <= Max loop
                        if Switch_Chars (Ptr) = 'M' then
                           First_Char := Ptr;
                           loop
                              Ptr := Ptr + 1;
                              exit when Ptr > Max
                                or else Switch_Chars (Ptr) not in '0' .. '9';
                           end loop;

                           Store_Compilation_Switch
                             ("-gnaty" & Switch_Chars (First_Char .. Ptr - 1));

                        else
                           Store_Compilation_Switch
                             ("-gnaty" & Switch_Chars (Ptr));
                           Ptr := Ptr + 1;
                        end if;
                     end loop;
                  end;
               end if;

            --  -gnatz (stub generation)

            when 'z' =>

               --  -gnatz must be the first and only switch in Switch_Chars,
               --  and is a two-letter switch.

               if Ptr /= Switch_Chars'First + 5
                 or else (Max - Ptr + 1) > 2
               then
                  Osint.Fail
                    ("-gnatz* may not be combined with other switches");
               end if;

               if Ptr = Max then
                  Bad_Switch ("-gnatz");
               end if;

               Ptr := Ptr + 1;

               --  Only one occurrence of -gnat* is permitted

               if Distribution_Stub_Mode = No_Stubs then
                  case Switch_Chars (Ptr) is
                     when 'r' =>
                        Distribution_Stub_Mode := Generate_Receiver_Stub_Body;

                     when 'c' =>
                        Distribution_Stub_Mode := Generate_Caller_Stub_Body;

                     when others =>
                        Bad_Switch ("-gnatz" & Switch_Chars (Ptr .. Max));
                  end case;

                  Ptr := Ptr + 1;

               else
                  Osint.Fail ("only one -gnatz* switch allowed");
               end if;

            --  -gnatZ (obsolescent)

            when 'Z' =>
               Ptr := Ptr + 1;
               Osint.Fail
                 ("-gnatZ is no longer supported: consider using --RTS=zcx");

            --  Note on language version switches: whenever a new language
            --  version switch is added, Switch.M.Normalize_Compiler_Switches
            --  must be updated.

            --  -gnat83

            when '8' =>
               if Ptr = Max then
                  Bad_Switch ("-gnat8");
               end if;

               Ptr := Ptr + 1;

               if Switch_Chars (Ptr) /= '3' or else Latest_Ada_Only then
                  Bad_Switch ("-gnat8" & Switch_Chars (Ptr .. Max));
               else
                  Ptr := Ptr + 1;
                  Ada_Version          := Ada_83;
                  Ada_Version_Explicit := Ada_83;
                  Ada_Version_Pragma   := Empty;
               end if;

            --  -gnat95

            when '9' =>
               if Ptr = Max then
                  Bad_Switch ("-gnat9");
               end if;

               Ptr := Ptr + 1;

               if Switch_Chars (Ptr) /= '5' or else Latest_Ada_Only then
                  Bad_Switch ("-gnat9" & Switch_Chars (Ptr .. Max));
               else
                  Ptr := Ptr + 1;
                  Ada_Version          := Ada_95;
                  Ada_Version_Explicit := Ada_95;
                  Ada_Version_Pragma   := Empty;
               end if;

            --  -gnat05

            when '0' =>
               if Ptr = Max then
                  Bad_Switch ("-gnat0");
               end if;

               Ptr := Ptr + 1;

               if Switch_Chars (Ptr) /= '5' or else Latest_Ada_Only then
                  Bad_Switch ("-gnat0" & Switch_Chars (Ptr .. Max));
               else
                  Ptr := Ptr + 1;
                  Ada_Version          := Ada_2005;
                  Ada_Version_Explicit := Ada_2005;
                  Ada_Version_Pragma   := Empty;
               end if;

            --  -gnat12

            when '1' =>
               if Ptr = Max then
                  Bad_Switch ("-gnat1");
               end if;

               Ptr := Ptr + 1;

               if Switch_Chars (Ptr) /= '2' then
                  Bad_Switch ("-gnat1" & Switch_Chars (Ptr .. Max));
               else
                  Ptr := Ptr + 1;
                  Ada_Version          := Ada_2012;
                  Ada_Version_Explicit := Ada_2012;
                  Ada_Version_Pragma   := Empty;
               end if;

            --  -gnat2005 and -gnat2012

            when '2' =>
               if Ptr > Max - 3 then
                  Bad_Switch ("-gnat" & Switch_Chars (Ptr .. Max));

               elsif Switch_Chars (Ptr .. Ptr + 3) = "2005"
                 and then not Latest_Ada_Only
               then
                  Ada_Version := Ada_2005;

               elsif Switch_Chars (Ptr .. Ptr + 3) = "2012" then
                  Ada_Version := Ada_2012;

               elsif Switch_Chars (Ptr .. Ptr + 3) = "2020" then
                  Ada_Version := Ada_2020;

               else
                  Bad_Switch ("-gnat" & Switch_Chars (Ptr .. Ptr + 3));
               end if;

               Ada_Version_Explicit := Ada_Version;
               Ada_Version_Pragma   := Empty;
               Ptr := Ptr + 4;

            --  Switch cancellation, currently only -gnat-p is allowed.
            --  All we do here is the error checking, since the actual
            --  processing for switch cancellation is done by calls to
            --  Switch_Subsequently_Cancelled at the appropriate point.

            when '-' =>

               --  Simple ignore -gnat-p

               if Switch_Chars = "-gnat-p" then
                  return;

               --  Any other occurrence of minus is ignored. This is for
               --  maximum compatibility with previous version which ignored
               --  all occurrences of minus.

               else
                  Store_Switch := False;
                  Ptr := Ptr + 1;
               end if;

            --  We ignore '/' in switches, this is historical, still needed???

            when '/' =>
               Store_Switch := False;

            --  Anything else is an error (illegal switch character)

            when others =>
               Bad_Switch ("-gnat" & Switch_Chars (Ptr .. Max));
            end case;

            if Store_Switch then
               Store_Compilation_Switch
                 ("-gnat" & Switch_Chars (First_Char .. Ptr - 1));
            end if;

            First_Switch := False;
         end loop;
      end if;
   end Scan_Front_End_Switches;

   -----------------------------------
   -- Switch_Subsequently_Cancelled --
   -----------------------------------

   function Switch_Subsequently_Cancelled
     (C        : String;
      Args     : String_List;
      Arg_Rank : Positive) return Boolean
   is
   begin
      --  Loop through arguments following the current one

      for Arg in Arg_Rank + 1 .. Args'Last loop
         if Args (Arg).all = "-gnat-" & C then
            return True;
         end if;
      end loop;

      --  No match found, not cancelled

      return False;
   end Switch_Subsequently_Cancelled;

end Switch.C;