aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/opt.ads
blob: 1a57074d89c4fcbdb23ecbc82e7d634cd37af9bf (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
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                                  O P T                                   --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 1992-2016, 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.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  This package contains global flags set by the initialization routine from
--  the command line and referenced throughout the compiler, the binder, or
--  other GNAT tools. The comments indicate which options are used by which
--  programs (GNAT, GNATBIND, GNATLINK, GNATMAKE, etc).

--  Some flags are labelled "PROJECT MANAGER". These are used by tools that
--  use the Project Manager. These tools include gnatmake, gnatname, the gnat
--  driver, gnatclean, gprbuild and gprclean.

with Hostparm; use Hostparm;
with Types;    use Types;

pragma Warnings (Off);
--  This package is used also by gnatcoll
with System.Strings; use System.Strings;
with System.WCh_Con; use System.WCh_Con;
pragma Warnings (On);

package Opt is

   ----------------------
   -- Checksum Control --
   ----------------------

   --  Checksums are computed for sources to check for sources being the same
   --  from a compilation point of view (e.g. spelling of identifiers and
   --  white space layout do not count in this computation).

   --  The way the checksum is computed has evolved across the various versions
   --  of GNAT. When gprbuild is called with -m, the checksums must be computed
   --  the same way in gprbuild as it was in the GNAT version of the compiler.
   --  The different ways are

   --    Version 6.4 and later:

   --      The Accumulate_Token_Checksum procedure is called after each numeric
   --      literal and each identifier/keyword. For keywords, Tok_Identifier is
   --      used in the call to Accumulate_Token_Checksum.

   --    Versions 5.04 to 6.3:

   --      For keywords, the token value were used in the call to procedure
   --      Accumulate_Token_Checksum. Type Token_Type did not include Tok_Some.

   --    Versions 5.03:

   --      For keywords, the token value were used in the call to
   --      Accumulate_Token_Checksum. Type Token_Type did not include
   --      Tok_Interface, Tok_Overriding, Tok_Synchronized and Tok_Some.

   --    Versions 5.02 and before:

   --      No calls to procedure Accumulate_Token_Checksum (the checksum
   --      mechanism was introduced in version 5.03).

   --  To signal to the scanner whether Accumulate_Token_Checksum needs to be
   --  called and what versions to call, the following Boolean flags are used:

   Checksum_Accumulate_Token_Checksum : Boolean := True;
   --  GPRBUILD
   --  Set to False by gprbuild when the version of GNAT is 5.02 or before. If
   --  this switch is False, then we do not call Accumulate_Token_Checksum, so
   --  the setting of the following two flags is irrelevant.

   Checksum_GNAT_6_3 : Boolean := False;
   --  GPRBUILD
   --  Set to True by gprbuild when the version of GNAT is 6.3 or before.

   Checksum_GNAT_5_03 : Boolean := False;
   --  GPRBUILD
   --  Set to True by gprbuild when the version of GNAT is 5.03 or before.

   ----------------------------------------------
   -- Settings of Modes for Current Processing --
   ----------------------------------------------

   --  The following mode values represent the current state of processing.
   --  The values set here are the default values. Unless otherwise noted,
   --  the value may be reset in Switch-? with an appropriate switch. In
   --  some cases, the values can also be modified by pragmas, and in the
   --  case of some binder variables, Gnatbind.Scan_Bind_Arg may modify
   --  the default values.

   Latest_Ada_Only : Boolean := False;
   --  If True, the only value valid for Ada_Version is Ada_Version_Type'Last,
   --  trying to specify other values will be ignored (in case of pragma
   --  Ada_xxx) or generate an error (in case of -gnat83/95/xx switches).

   type Ada_Version_Type is (Ada_83, Ada_95, Ada_2005, Ada_2012);
   pragma Ordered (Ada_Version_Type);
   --  Versions of Ada for Ada_Version below. Note that these are ordered,
   --  so that tests like Ada_Version >= Ada_95 are legitimate and useful.
   --  Think twice before using "="; Ada_Version >= Ada_2012 is more likely
   --  what you want, because it will apply to future versions of the language.

   Ada_Version_Default : constant Ada_Version_Type := Ada_2012;
   pragma Warnings (Off, Ada_Version_Default);
   --  GNAT
   --  Default Ada version if no switch given. The Warnings off is to kill
   --  constant condition warnings.

   Ada_Version : Ada_Version_Type := Ada_Version_Default;
   --  GNAT
   --  Current Ada version for compiler, as set by configuration pragmas,
   --  compiler switches, or implicitly (to Ada_Version_Runtime) when a
   --  predefined or internal file is compiled.

   Ada_Version_Pragma : Node_Id := Empty;
   --  Reflects the Ada_xxx pragma that resulted in setting Ada_Version. Used
   --  to specialize error messages complaining about the Ada version in use.

   Ada_Version_Explicit : Ada_Version_Type := Ada_Version_Default;
   --  GNAT
   --  Like Ada_Version, but does not get set implicitly for predefined or
   --  internal units, so it reflects the Ada version explicitly set using
   --  configuration pragmas or compiler switches (or if neither appears, it
   --  remains set to Ada_Version_Default). This is used in the rare cases
   --  (notably pragma Obsolescent) where we want the explicit version set.

   Ada_Version_Runtime : Ada_Version_Type := Ada_2012;
   --  GNAT
   --  Ada version used to compile the runtime. Used to set Ada_Version (but
   --  not Ada_Version_Explicit) when compiling predefined or internal units.

   Ada_Final_Suffix : constant String := "final";
   Ada_Final_Name   : String_Ptr := new String'("ada" & Ada_Final_Suffix);
   --  GNATBIND
   --  The name of the procedure that performs the finalization at the end of
   --  execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.

   Ada_Init_Suffix : constant String := "init";
   Ada_Init_Name   : String_Ptr := new String'("ada" & Ada_Init_Suffix);
   --  GNATBIND
   --  The name of the procedure that performs initialization at the start
   --  of execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.

   Ada_Main_Name_Suffix : constant String := "main";
   --  GNATBIND
   --  The suffix for Ada_Main_Name. Defined as a constant here so that it
   --  can be referenced in a uniform manner to create either the default
   --  value of Ada_Main_Name (declared below), or the non-default name
   --  set by Gnatbind.Scan_Bind_Arg.

   Ada_Main_Name : String_Ptr := new String'("ada_" & Ada_Main_Name_Suffix);
   --  GNATBIND
   --  The name of the Ada package generated by the binder (when in Ada mode).
   --  This variable may be modified by Gnatbind.Scan_Bind_Arg.

   Address_Clause_Overlay_Warnings : Boolean := True;
   --  GNAT
   --  Set False to disable address clause warnings. Modified by use of
   --  -gnatwo/O.

   Address_Is_Private : Boolean := False;
   --  GNAT, GNATBIND
   --  Set True if package System has the line "type Address is private;"

   All_Errors_Mode : Boolean := False;
   --  GNAT
   --  Flag set to force display of multiple errors on a single line and
   --  also repeated error messages for references to undefined identifiers
   --  and certain other repeated error messages. Set by use of -gnatf.

   Allow_Integer_Address : Boolean := False;
   --  GNAT
   --  Allow use of integer expression in a context requiring System.Address.
   --  Set by the use of configuration pragma Allow_Integer_Address Also set
   --  in relaxed semantics mode for use by CodePeer or when -gnatd.M is used.

   All_Sources : Boolean := False;
   --  GNATBIND
   --  Set to True to require all source files to be present. This flag is
   --  directly modified by gnatmake to affect the shared binder routines.

   Alternate_Main_Name : String_Ptr := null;
   --  GNATBIND
   --  Set to non-null when Bind_Alternate_Main_Name is True. This value
   --  is modified as needed by Gnatbind.Scan_Bind_Arg.

   ASIS_GNSA_Mode : Boolean := False;
   --  GNAT
   --  Enable GNSA back-end processing assuming ASIS_Mode is already set to
   --  True. ASIS_GNSA mode suppresses the call to gigi.

   ASIS_Mode : Boolean := False;
   --  GNAT
   --  Enable semantic checks and tree transformations that are important
   --  for ASIS but that are usually skipped if Operating_Mode is set to
   --  Check_Semantics. This flag does not have the corresponding option to set
   --  it ON. It is set ON when Tree_Output is set ON, it can also be set ON
   --  from the code of GNSA-based tool (a client may need to set ON the
   --  Back_Annotate_Rep_Info flag in this case. At the moment this does not
   --  make very much sense, because GNSA cannot do back annotation).

   Assertions_Enabled : Boolean := False;
   --  GNAT
   --  Indicates default policy (True = Check, False = Ignore) to be applied
   --  to all assertion aspects and pragmas, and to pragma Debug, if there is
   --  no overriding Assertion_Policy, Check_Policy, or Debug_Policy pragma.
   --  Set True by use of -gnata.

   Assume_No_Invalid_Values : Boolean := False;
   --  GNAT Normally, in accordance with (RM 13.9.1 (9-11)) the front end
   --  assumes that values could have invalid representations, unless it can
   --  clearly prove that the values are valid. If this switch is set (by
   --  pragma Assume_No_Invalid_Values (On)), then the compiler assumes values
   --  are valid and in range of their representations. This feature is now
   --  fully enabled in the compiler.

   Back_Annotate_Rep_Info : Boolean := False;
   --  GNAT
   --  If set True, enables back annotation of representation information
   --  by gigi, even in -gnatc mode. This is set True by the use of -gnatR
   --  (list representation information) or -gnatt (generate tree). It is
   --  also set true if certain Unchecked_Conversion instantiations require
   --  checking based on annotated values.

   Back_End_Handles_Limited_Types : Boolean;
   --  This flag is set true if the back end can properly handle limited or
   --  other by reference types, and avoid copies. If this flag is False, then
   --  the front end does special expansion for if/case expressions to make
   --  sure that no copy occurs. If the flag is True, then the expansion for
   --  if and case expressions relies on the back end properly handling things.
   --  Currently the default is False for all cases (set in gnat1drv). The
   --  default can be modified using -gnatd.L (sets the flag True). This is
   --  used to test the possibility of having the backend handle this.

   Back_End_Inlining : Boolean := False;
   --  GNAT
   --  Set True to activate inlining by back-end expansion. This is the normal
   --  default mode for gcc targets, so it is True on such targets unless the
   --  switches -gnatN or -gnatd.z are used. See circuitry in gnat1drv for the
   --  exact conditions for setting this switch.

   Bind_Alternate_Main_Name : Boolean := False;
   --  GNATBIND
   --  True if main should be called Alternate_Main_Name.all.
   --  This variable may be set to True by Gnatbind.Scan_Bind_Arg.

   Bind_Main_Program : Boolean := True;
   --  GNATBIND
   --  Set to False if not binding main Ada program

   Bind_For_Library : Boolean := False;
   --  GNATBIND
   --  Set to True if the binder needs to generate a file designed for building
   --  a library. May be set to True by Gnatbind.Scan_Bind_Arg.

   Bind_Only : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set to True to skip compile and link steps
   --  (except when Compile_Only and/or Link_Only are True).

   Blank_Deleted_Lines : Boolean := False;
   --  GNAT, GNATPREP
   --  Output empty lines for each line of preprocessed input that is deleted
   --  in the output, including preprocessor lines starting with a '#'.

   Brief_Output : Boolean := False;
   --  GNAT, GNATBIND
   --  Force brief error messages to standard error, even if verbose mode is
   --  set (so that main error messages go to standard output).

   Build_Bind_And_Link_Full_Project : Boolean := False;
   --  GNATMAKE
   --  Set to True to build, bind and link all the sources of a project file
   --  (switch -B)

   Check_Aliasing_Of_Parameters : Boolean := False;
   --  GNAT
   --  Set to True to detect whether subprogram parameters and function results
   --  alias the same object(s).

   Check_Float_Overflow : Boolean := False;
   --  GNAT
   --  Set to True to check that operations on predefined unconstrained float
   --  types (e.g. Float, Long_Float) do not overflow and generate infinities
   --  or invalid values. Set by the Check_Float_Overflow pragma, or by use
   --  of the -gnateF switch.

   Check_Object_Consistency : Boolean := False;
   --  GNATBIND, GNATMAKE
   --  Set to True to check whether every object file is consistent with its
   --  corresponding ada library information (ALI) file. An object file is
   --  inconsistent with the corresponding ALI file if the object file does
   --  not exist or if it has an older time stamp than the ALI file. Default
   --  above is for GNATBIND. GNATMAKE overrides this default to True (see
   --  Make.Initialize) since we normally do need to check source consistencies
   --  in gnatmake.

   Check_Only : Boolean := False;
   --  GNATBIND
   --  Set to True to do checks only, no output of binder file

   Check_Policy_List : Node_Id := Empty;
   --  GNAT
   --  This points to the list of N_Pragma nodes for Check_Policy pragmas
   --  that are linked through the Next_Pragma fields, with the list being
   --  terminated by Empty. The order is most recently processed first. Note
   --  that Push_Scope and Pop_Scope in Sem_Ch8 save and restore the value
   --  of this variable, implementing the required scope control for pragmas
   --  appearing in a declarative part.

   Check_Readonly_Files : Boolean := False;
   --  GNATMAKE
   --  Set to True to check readonly files during the make process

   Check_Source_Files : Boolean := True;
   --  GNATBIND, GNATMAKE
   --  Set to True to enable consistency checking for any source files that
   --  are present (i.e. date must match the date in the library info file).
   --  Set to False for object file consistency check only. This flag is
   --  directly modified by gnatmake, to affect the shared binder routines.

   Check_Switches : Boolean := False;
   --  GNATMAKE, GPBUILD
   --  Set to True to check compiler options during the make process

   Check_Unreferenced : Boolean := False;
   --  GNAT
   --  Set to True to enable checking for unreferenced entities other
   --  than formal parameters (for which see Check_Unreferenced_Formals)
   --  Modified by use of -gnatwu/U.

   Check_Unreferenced_Formals : Boolean := False;
   --  GNAT
   --  Set to True to check for unreferenced formals. This is turned on by
   --  -gnatwa/wf/wu and turned off by -gnatwA/wF/wU.

   Check_Validity_Of_Parameters : Boolean := False;
   --  GNAT
   --  Set to True to check for proper scalar initialization of subprogram
   --  parameters on both entry and exit. Turned on by??? turned off by???

   Check_Withs : Boolean := False;
   --  GNAT
   --  Set to True to enable checking for unused withs, and also the case
   --  of withing a package and using none of the entities in the package.
   --  Modified by use of -gnatwu/U.

   CodePeer_Mode : Boolean := False;
   --  GNAT, GNATBIND, GPRBUILD
   --  Enable full CodePeer mode (SCIL generation, disable switches that
   --  interact badly with it, etc...). This is turned on by -gnatC.

   Commands_To_Stdout : Boolean := False;
   --  GNATMAKE
   --  True if echoed commands to be written to stdout instead of stderr

   Comment_Deleted_Lines : Boolean := False;
   --  GNATPREP
   --  True if source lines removed by the preprocessor should be commented
   --  in the output file.

   Compilation_Time : String (1 .. 19);
   --  GNAT
   --  Compilation date and time in form YYYY-MM-DD HH:MM:SS

   Compile_Only : Boolean := False;
   --  GNATMAKE, GNATCLEAN, GPBUILD, GPRCLEAN
   --  GNATMAKE, GPRBUILD:
   --    set True to skip bind and link steps (except when Bind_Only is True)
   --  GNATCLEAN, GPRCLEAN:
   --    set True to delete only the files produced by the compiler but not the
   --    library files or the executable files.

   Compiler_Unit : Boolean := False;
   --  GNAT1
   --  Set True by an occurrence of pragma Compiler_Unit_Warning (or of the
   --  obsolete pragma Compiler_Unit) in the main unit. Once set True, stays
   --  True, since any units that are with'ed directly or indirectly by
   --  a Compiler_Unit_Warning main unit are subject to the same restrictions.
   --  Such units really should have their own pragmas, but we do not bother to
   --  check for that, so this transitivity provides extra checking.

   Config_File : Boolean := True;
   --  GNAT
   --  Set to False to inhibit reading and processing of gnat.adc file

   Config_File_Names : String_List_Access := null;
   --  GNAT
   --  Names of configuration pragmas files (given by switches -gnatec)

   Configurable_Run_Time_Mode : Boolean := False;
   --  GNAT, GNATBIND
   --  Set True if the compiler is operating in configurable run-time mode.
   --  This happens if the flag Targparm.Configurable_Run_TimeMode_On_Target
   --  is set True, or if pragma No_Run_Time is used. See the spec of Rtsfind
   --  for details on the handling of the latter pragma.

   Constant_Condition_Warnings : Boolean := False;
   --  GNAT
   --  Set to True to activate warnings on constant conditions. Modified by
   --  use of -gnatwc/C.

   Create_Mapping_File : Boolean := False;
   --  GNATMAKE
   --  Set to True (-C switch) to indicate that the compiler will be invoked
   --  with a mapping file (-gnatem compiler switch).

   subtype Debug_Level_Value is Nat range 0 .. 3;
   Debugger_Level : Debug_Level_Value := 0;
   --  GNAT, GNATBIND
   --  The value given to the -g parameter. The default value for -g with
   --  no value is 2. If no -g is specified, defaults to 0.
   --  Note that the generated code should never depend on this variable,
   --  since we want debug info to be nonintrusive on the generate code.

   Default_Exit_Status : Int := 0;
   --  GNATBIND
   --  Set the default exit status value. Set by the -Xnnn switch for the
   --  binder.

   Debug_Generated_Code : Boolean := False;
   --  GNAT
   --  Set True (-gnatD switch) to debug generated expanded code instead
   --  of the original source code. Causes debugging information to be
   --  written with respect to the generated code file that is written.

   Default_Pool : Node_Id := Empty;
   --  GNAT
   --  Used to record the storage pool name (or null literal) that is the
   --  argument of an applicable pragma Default_Storage_Pool.
   --    Empty:       No pragma Default_Storage_Pool applies.
   --    N_Null node: "pragma Default_Storage_Pool (null);" applies.
   --    otherwise:   "pragma Default_Storage_Pool (X);" applies, and
   --                 this points to the name X.
   --  Push_Scope and Pop_Scope in Sem_Ch8 save and restore this value.
   Default_Stack_Size : Int := -1;
   --  GNATBIND
   --  Set to default primary stack size in units of bytes. Set by
   --  the -dnnn switch for the binder. A value of -1 indicates that no
   --  default was set by the binder.

   Default_Sec_Stack_Size : Int := -1;
   --  GNATBIND
   --  Set to default secondary stack size in units of bytes. Set by
   --  the -Dnnn switch for the binder. A value of -1 indicates that no
   --  default was set by the binder, and that the default should be the
   --  initial value of System.Secondary_Stack.Default_Secondary_Stack_Size.

   Default_SSO : Character := ' ';
   --  GNAT
   --  Set if a pragma Default_Scalar_Storage_Order has been given. The value
   --  of ' ' indicates that no default has been set, otherwise the value is
   --  either 'H' for High_Order_First or 'L' for Lower_Order_First.

   Detect_Blocking : Boolean := False;
   --  GNAT
   --  Set True to force the run time to raise Program_Error if calls to
   --  potentially blocking operations are detected from protected actions.

   Directories_Must_Exist_In_Projects : Boolean := True;
   --  PROJECT MANAGER
   --  Set to False with switch -f of gnatclean and gprclean

   Display_Compilation_Progress : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set True (-d switch) to display information on progress while compiling
   --  files. Internal flag to be used in conjunction with an IDE (e.g GPS).

   type Distribution_Stub_Mode_Type is
   --  GNAT
     (No_Stubs,
      --  Normal mode, no generation/compilation of distribution stubs

      Generate_Receiver_Stub_Body,
      --  The unit being compiled is the RCI body, and the compiler will
      --  generate the body for the receiver stubs and compile it.

      Generate_Caller_Stub_Body);
      --  The unit being compiled is the RCI spec, and the compiler will
      --  generate the body for the caller stubs and compile it.

   Distribution_Stub_Mode : Distribution_Stub_Mode_Type := No_Stubs;
   --  GNAT
   --  This enumeration variable indicates the five states of distribution
   --  annex stub generation/compilation.

   Do_Not_Execute : Boolean := False;
   --  GNATMAKE
   --  Set to True if no actual compilations should be undertaken

   Dump_Source_Text : Boolean := False;
   --  GNAT
   --  Set to True (by -gnatL) to dump source text intermingled with generated
   --  code. Effective only if either of Debug/Print_Generated_Code is true.

   Dynamic_Elaboration_Checks : Boolean := False;
   --  GNAT
   --  Set True for dynamic elaboration checking mode, as set by the -gnatE
   --  switch or by the use of pragma Elaboration_Checks (Dynamic).

   Dynamic_Stack_Measurement : Boolean := False;
   --  GNATBIND
   --  Set True to enable dynamic stack measurement (-u flag for gnatbind)

   Dynamic_Stack_Measurement_Array_Size : Nat := 100;
   --  GNATBIND
   --  Number of measurements we want to store during dynamic stack analysis.
   --  When the buffer is full, non-storable results will be output on the fly.
   --  The value is relevant only if Dynamic_Stack_Measurement is set. Set
   --  by processing of -u flag for gnatbind.

   Elab_Dependency_Output : Boolean := False;
   --  GNATBIND
   --  Set to True to output complete list of elaboration constraints

   Elab_Order_Output : Boolean := False;
   --  GNATBIND
   --  Set to True to output chosen elaboration order

   Elab_Info_Messages : Boolean := False;
   --  GNAT
   --  Set to True to output info messages for static elabmodel (-gnatel)

   Elab_Warnings : Boolean := False;
   --  GNAT
   --  Set to True to generate elaboration warnings (-gnatwl)

   Error_Msg_Line_Length : Nat := 0;
   --  GNAT
   --  Records the error message line length limit. If this is set to zero,
   --  then we get the old style behavior, in which each call to the error
   --  message routines generates one line of output as a separate message.
   --  If it is set to a non-zero value, then continuation lines are folded
   --  to make a single long message, and then this message is split up into
   --  multiple lines not exceeding the specified length. Set by -gnatj=nn.

   Error_To_Warning : Boolean := False;
   --  GNAT
   --  If True, then certain error messages (e.g. parameter overlap messages
   --  for procedure calls in Ada 2012 mode) are treated as warnings instead
   --  of errors. Set by debug flag -gnatd.E. A search for Error_To_Warning
   --  will identify affected messages.

   Exception_Handler_Encountered : Boolean := False;
   --  GNAT
   --  This flag is set true if the parser encounters an exception handler.
   --  It is used to set Warn_On_Exception_Propagation True if the restriction
   --  No_Exception_Propagation is set.

   Exception_Extra_Info : Boolean := False;
   --  GNAT
   --  True when switch -gnateE is used. When True, generate extra information
   --  associated with exception messages (in particular range and index
   --  checks).

   Exception_Locations_Suppressed : Boolean := False;
   --  GNAT
   --  Set to True if a Suppress_Exception_Locations configuration pragma is
   --  currently active.

   type Exception_Mechanism_Type is
   --  Determines the kind of mechanism used to handle exceptions
   --
     (Front_End_SJLJ,
      --  Exceptions use setjmp/longjmp generated explicitly by the front end
      --  (this includes gigi or other equivalent parts of the code generator).
      --  AT END handlers are converted into exception handlers by the front
      --  end in this mode.

      Back_End_ZCX,
      --  Exceptions are handled by the back end. The front end simply
      --  generates the handlers as they appear in the source, and AT END
      --  handlers are left untouched (they are not converted into exception
      --  handlers when operating in this mode). Propagation is performed
      --  using a frame unwinding scheme and requires no particular setup code
      --  at handler sites on regular execution paths.

      Back_End_SJLJ);
      --  Similar to Back_End_ZCX with respect to the front-end processing
      --  of regular and AT-END handlers. A setjmp/longjmp scheme is used to
      --  propagate and setup handler contexts on regular execution paths.

   pragma Convention (C, Exception_Mechanism_Type);

   Exception_Mechanism : Exception_Mechanism_Type := Front_End_SJLJ;
   --  GNAT
   --  Set to the appropriate value depending on the flags in system.ads
   --  (Frontend_Exceptions + ZCX_By_Default). The C convention is there to
   --  allow access by gigi.

   function Back_End_Exceptions return Boolean;
   function Front_End_Exceptions return Boolean;
   function ZCX_Exceptions return Boolean;
   function SJLJ_Exceptions return Boolean;
   --  GNAT
   --  Various properties of the active Exception_Mechanism

   Exception_Tracebacks : Boolean := False;
   --  GNATBIND
   --  Set to True to store tracebacks in exception occurrences (-Ea or -E)

   Exception_Tracebacks_Symbolic : Boolean := False;
   --  GNATBIND
   --  Set to True to store tracebacks in exception occurrences and enable
   --  symbolic tracebacks (-Es).

   Extensions_Allowed : Boolean := False;
   --  GNAT
   --  Set to True by switch -gnatX if GNAT specific language extensions
   --  are allowed. Currently there are no such defined extensions.

   type External_Casing_Type is (
     As_Is,       -- External names cased as they appear in the Ada source
     Uppercase,   -- External names forced to all uppercase letters
     Lowercase);  -- External names forced to all lowercase letters

   External_Name_Imp_Casing : External_Casing_Type := Lowercase;
   --  GNAT
   --  The setting of this flag determines the casing of external names
   --  when the name is implicitly derived from an entity name (i.e. either
   --  no explicit External_Name or Link_Name argument is used, or, in the
   --  case of extended DEC pragmas, the external name is given using an
   --  identifier. The As_Is setting is not permitted here (since this would
   --  create Ada source programs that were case sensitive).

   External_Name_Exp_Casing : External_Casing_Type := As_Is;
   --  GNAT
   --  The setting of this flag determines the casing of an external name
   --  specified explicitly with a string literal. As_Is means the string
   --  literal is used as given with no modification to the casing. If
   --  Lowercase or Uppercase is set, then the string is forced to all
   --  lowercase or all uppercase letters as appropriate. Note that this
   --  setting has no effect if the external name is given using an identifier
   --  in the case of extended DEC import/export pragmas (in this case the
   --  casing is controlled by External_Name_Imp_Casing), and also has no
   --  effect if an explicit Link_Name is supplied (a link name is always
   --  used exactly as given).

   External_Unit_Compilation_Allowed : Boolean := False;
   --  GNATMAKE
   --  When True (set by gnatmake switch -x), allow compilation of sources
   --  that are not part of any project file.

   Fast_Math : Boolean := False;
   --  GNAT
   --  Indicates the current setting of Fast_Math mode, as set by the use
   --  of a Fast_Math pragma (set True by Fast_Math (On)).

   Force_ALI_Tree_File : Boolean := False;
   --  GNAT
   --  Force generation of ALI file even if errors are encountered. Also forces
   --  generation of tree file if -gnatt is also set. Set on by use of -gnatQ.

   Disable_ALI_File : Boolean := False;
   --  GNAT
   --  Disable generation of ALI file

   Follow_Links_For_Files : Boolean := False;
   --  PROJECT MANAGER
   --  Set to True (-eL) to process the project files in trusted mode. If
   --  Follow_Links is False, it is assumed that the project doesn't contain
   --  any file duplicated through symbolic links (although the latter are
   --  still valid if they point to a file which is outside of the project),
   --  and that no directory has a name which is a valid source name.

   Follow_Links_For_Dirs : Boolean := False;
   --  PROJECT MANAGER
   --  Set to True if directories can be links in this project, and therefore
   --  additional system calls must be performed to ensure that we always see
   --  the same full name for each directory.

   Force_Checking_Of_Elaboration_Flags : Boolean := False;
   --  GNATBIND
   --  True if binding with forced checking of the elaboration flags
   --  (-F switch set).

   Force_Compilations : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set to force recompilations even when the objects are up-to-date.

   Force_Elab_Order_File : String_Ptr := null;
   --  GNATBIND
   --  File name specified for -f switch (the forced elaboration order file)

   Front_End_Inlining : Boolean := False;
   --  GNAT
   --  Set True to activate inlining by front-end expansion (even on GCC
   --  targets, where inlining is normally handled by the back end). Set by
   --  the flag -gnatN (which is now considered obsolescent, since the GCC
   --  back end can do a better job of inlining than the front end these days.

   Full_Path_Name_For_Brief_Errors : Boolean := False;
   --  PROJECT MANAGER
   --  When True, in Brief_Output mode, each error message line will start with
   --  the full path name of the source. When False, only the file name without
   --  directory information is used.

   Full_List : Boolean := False;
   --  GNAT
   --  Set True to generate full source listing with embedded errors

   Full_List_File_Name : String_Ptr := null;
   --  GNAT
   --  Set to file name to generate full source listing to named file (or if
   --  the name is of the form .xxx, then to name.xxx where name is the source
   --  file name with extension stripped.

   Generate_C_Code : Boolean := False;
   --  GNAT
   --  If True, the Cprint circuitry to generate C code output is activated.
   --  Set True by use of -gnateg or -gnatd.V.

   Generate_CodePeer_Messages : Boolean := False;
   --  GNAT
   --  Generate CodePeer messages. Ignored if CodePeer_Mode is false. This is
   --  turned on by -gnateC.

   Generate_Processed_File : Boolean := False;
   --  GNAT
   --  True when switch -gnateG is used. When True, create in a file
   --  <source>.prep, if the source is preprocessed.

   Generate_SCIL : Boolean := False;
   --  GNAT
   --  Set True to activate SCIL code generation.

   Generate_SCO : Boolean := False;
   --  GNAT
   --  True when switch -fdump-scos (or -gnateS) is used. When True, Source
   --  Coverage Obligation (SCO) information is generated and output in the ALI
   --  file. See unit Par_SCO for full details.

   Generate_SCO_Instance_Table : Boolean := False;
   --  GNAT
   --  True when switch -fdump-scos is used. When True, a table of instances is
   --  included in SCOs.

   Generating_Code : Boolean := False;
   --  GNAT
   --  True if the frontend finished its work and has called the backend to
   --  process the tree and generate the object file.

   type Ghost_Mode_Type is (None, Check, Ignore);
   --  Possible legal modes that can be set by aspect/pragma Ghost as well as
   --  value None, which indicates that no such aspect/pragma applies.

   Ghost_Mode : Ghost_Mode_Type := None;
   --  GNAT
   --  Current Ghost mode setting

   Global_Discard_Names : Boolean := False;
   --  GNAT, GNATBIND
   --  True if a pragma Discard_Names appeared as a configuration pragma for
   --  the current compilation unit.

   GNAT_Encodings : Int;
   pragma Import (C, GNAT_Encodings, "gnat_encodings");
   --  Constant controlling the balance between GNAT encodings and standard
   --  DWARF to emit in the debug information. It accepts the following values.

   DWARF_GNAT_Encodings_All     : constant Int := 0;
   DWARF_GNAT_Encodings_GDB     : constant Int := 1;
   DWARF_GNAT_Encodings_Minimal : constant Int := 2;

   Identifier_Character_Set : Character;
   --  GNAT
   --  This variable indicates the character set to be used for identifiers.
   --  The possible settings are:
   --    '1'  Latin-1 (ISO-8859-1)
   --    '2'  Latin-2 (ISO-8859-2)
   --    '3'  Latin-3 (ISO-8859-3)
   --    '4'  Latin-4 (ISO-8859-4)
   --    '5'  Latin-Cyrillic (ISO-8859-5)
   --    '9'  Latin-9 (ISO-8859-15)
   --    'p'  PC (US, IBM page 437)
   --    '8'  PC (European, IBM page 850)
   --    'f'  Full upper set (all distinct)
   --    'n'  No upper characters (Ada 83 rules)
   --    'w'  Latin-1 plus wide characters allowed in identifiers
   --
   --  The setting affects the set of letters allowed in identifiers and the
   --  upper/lower case equivalences. It does not affect the interpretation of
   --  character and string literals, which are always stored using the actual
   --  coding in the source program. This variable is initialized to the
   --  default value appropriate to the system (in Osint.Initialize), and then
   --  reset if a command line switch is used to change the setting.

   Ignore_Pragma_SPARK_Mode : Boolean := False;
   --  GNAT
   --  Set True to ignore the semantics and effects of pragma SPARK_Mode when
   --  the pragma appears inside an instance whose enclosing context is subject
   --  to SPARK_Mode "off".

   Ignore_Rep_Clauses : Boolean := False;
   --  GNAT
   --  Set True to ignore all representation clauses. Useful when compiling
   --  code from foreign compilers for checking or ASIS purposes. Can be
   --  set True by use of -gnatI.

   Ignore_Style_Checks_Pragmas : Boolean := False;
   --  GNAT
   --  Set True to ignore all Style_Checks pragmas. Can be set True by use
   --  of -gnateY.

   Ignore_Unrecognized_VWY_Switches : Boolean := False;
   --  GNAT
   --  Set True to ignore unrecognized y, V, w switches. Can be set True
   --  by use of -gnateu, causing subsequent unrecognized switches to result
   --  in a warning rather than an error.

   Implementation_Unit_Warnings : Boolean := True;
   --  GNAT
   --  Set True to active warnings for use of implementation internal units.
   --  Modified by use of -gnatwi/-gnatwI.

   Implicit_Packing : Boolean := False;
   --  GNAT
   --  If set True, then a Size attribute clause on an array is allowed to
   --  cause implicit packing instead of generating an error message. Set by
   --  use of pragma Implicit_Packing.

   Ineffective_Inline_Warnings : Boolean := False;
   --  GNAT
   --  Set True to activate warnings if front-end inlining (-gnatN) is not able
   --  to actually inline a particular call (or all calls). Can be controlled
   --  by use of -gnatwp/-gnatwP. Also set True to activate warnings if
   --  frontend inlining is not able to inline a subprogram expected to
   --  be inlined in GNATprove mode.

   Init_Or_Norm_Scalars : Boolean := False;
   --  GNAT, GNATBIND
   --  Set True if a pragma Initialize_Scalars applies to the current unit.
   --  Also set True if a pragma Restriction (Normalize_Scalars) applies.

   Initialize_Scalars : Boolean := False;
   --  GNAT
   --  Set True if a pragma Initialize_Scalars applies to the current unit.
   --  Note that Init_Or_Norm_Scalars is also set to True if this is True.

   Initialize_Scalars_Mode1 : Character := 'I';
   Initialize_Scalars_Mode2 : Character := 'N';
   --  GNATBIND
   --  Set to two characters from -S switch (IN/LO/HI/EV/xx). The default
   --  is IN (invalid values), used if no -S switch is used.

   Inline_Active : Boolean := False;
   --  GNAT
   --  Set True to activate pragma Inline processing across modules. Default
   --  for now is not to inline across module boundaries.

   Inline_Level : Nat := 0;
   --  GNAT
   --  Set to indicate the inlining level: 0 means that an appropriate value is
   --  to be computed by the compiler based on the optimization level (-gnatn),
   --  1 is for moderate inlining across modules (-gnatn1) and 2 for full
   --  inlining across modules (-gnatn2).

   Interface_Library_Unit : Boolean := False;
   --  GNATBIND
   --  Set to True to indicate that at least one ALI file is an interface ALI:
   --  then elaboration flag checks are to be generated in the binder
   --  generated file.

   Invalid_Value_Used : Boolean := False;
   --  GNAT
   --  Set True if a valid Invalid_Value attribute is encountered

   Inline_Processing_Required : Boolean := False;
   --  GNAT
   --  Set True if inline processing is required. Inline processing is required
   --  if an active Inline pragma is processed. The flag is set for a pragma
   --  Inline or Inline_Always that is actually active.

   In_Place_Mode : Boolean := False;
   --  GNATMAKE
   --  Set True to store ALI and object files in place i.e. in the object
   --  directory if these files already exist or in the source directory
   --  if not.

   Keep_Going : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  When True signals to ignore compilation errors and keep processing
   --  sources until there is no more work.

   Keep_Temporary_Files : Boolean := False;
   --  GNATCMD, GNATMAKE, GPRBUILD
   --  When True the temporary files are not deleted. Set by switches -dn or
   --  --keep-temp-files.

   Leap_Seconds_Support : Boolean := False;
   --  GNATBIND
   --  Set to True to enable leap seconds support in Ada.Calendar and its
   --  children.

   Link_Only : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set to True to skip compile and bind steps (except when Bind_Only is
   --  set to True).

   List_Body_Required_Info : Boolean := False;
   --  GNATMAKE
   --  List info messages about why a package requires a body. Modified by use
   --  of -gnatw.y/.Y.

   List_Inherited_Aspects : Boolean := False;
   --  GNAT
   --  List inherited invariants, preconditions, and postconditions from
   --  Invariant'Class, Pre'Class, and Post'Class aspects. Also list inherited
   --  subtype predicates. Modified by use of -gnatw.l/.L.

   List_Restrictions : Boolean := False;
   --  GNATBIND
   --  Set to True to list restrictions pragmas that could apply to partition

   List_Units : Boolean := False;
   --  GNAT
   --  List units in the active library for a compilation (-gnatu switch)

   List_Closure : Boolean := False;
   --  GNATBIND
   --  List all sources in the closure of a main (-R or -Ra gnatbind switch)

   List_Closure_All : Boolean := False;
   --  GNATBIND
   --  List all sources in closure of main including run-time units (-Ra
   --  gnatbind switch).

   List_Dependencies : Boolean := False;
   --  GNATMAKE
   --  When True gnatmake verifies that the objects are up to date and outputs
   --  the list of object dependencies (-M switch). Output depends if -a switch
   --  is used or not. This list can be used directly in a Makefile.

   List_Representation_Info : Int range 0 .. 3 := 0;
   --  GNAT
   --  Set non-zero by -gnatR switch to list representation information.
   --  The settings are as follows:
   --
   --    0 = no listing of representation information (default as above)
   --    1 = list rep info for user defined record and array types
   --    2 = list rep info for all user defined types and objects
   --    3 = like 2, but variable fields are decoded symbolically

   List_Representation_Info_To_File : Boolean := False;
   --  GNAT
   --  Set true by -gnatRs switch. Causes information from -gnatR/1/2/3/m to be
   --  written to file.rep (where file is the name of the source file) instead
   --  of stdout. For example, if file x.adb is compiled using -gnatR2s then
   --  representation info is written to x.adb.ref.

   List_Representation_Info_Mechanisms : Boolean := False;
   --  GNAT
   --  Set true by -gnatRm switch. Causes information on mechanisms to be
   --  included in the representation output information.

   List_Preprocessing_Symbols : Boolean := False;
   --  GNAT, GNATPREP
   --  Set to True if symbols for preprocessing a source are to be listed
   --  before preprocessing occurs. Set to True by switch -s of gnatprep or
   --  -s in preprocessing data file for the compiler.

   type Create_Repinfo_File_Proc is access procedure (Src  : String);
   type Write_Repinfo_Line_Proc  is access procedure (Info : String);
   type Close_Repinfo_File_Proc  is access procedure;
   --  Types used for procedure addresses below

   Create_Repinfo_File_Access : Create_Repinfo_File_Proc := null;
   Write_Repinfo_Line_Access  : Write_Repinfo_Line_Proc  := null;
   Close_Repinfo_File_Access  : Close_Repinfo_File_Proc  := null;
   --  GNAT
   --  These three locations are left null when operating in non-compiler (e.g.
   --  ASIS mode), but when operating in compiler mode, they are set to point
   --  to the three corresponding procedures in Osint-C. The reason for this
   --  slightly strange interface is to stop Repinfo from dragging in Osint in
   --  ASIS mode, which would include lots of unwanted units in the ASIS build.

   type Create_List_File_Proc is access procedure (S : String);
   type Write_List_Info_Proc  is access procedure (S : String);
   type Close_List_File_Proc  is access procedure;
   --  Types used for procedure addresses below

   Create_List_File_Access : Create_List_File_Proc := null;
   Write_List_Info_Access  : Write_List_Info_Proc  := null;
   Close_List_File_Access  : Close_List_File_Proc  := null;
   --  GNAT
   --  These three locations are left null when operating in non-compiler
   --  (e.g. from the binder), but when operating in compiler mode, they are
   --  set to point to the three corresponding procedures in Osint-C. The
   --  reason for this slightly strange interface is to prevent Repinfo
   --  from dragging in Osint-C in the binder, which would include unwanted
   --  units in the binder.

   Locking_Policy : Character := ' ';
   --  GNAT, GNATBIND
   --  Set to ' ' for the default case (no locking policy specified). Reset to
   --  first character (uppercase) of locking policy name if a valid pragma
   --  Locking_Policy is encountered.

   Locking_Policy_Sloc : Source_Ptr := No_Location;
   --  GNAT, GNATBIND
   --  Remember location of previous Locking_Policy pragma. This is used for
   --  inconsistency error messages. A value of System_Location is used if the
   --  policy is set in package System.

   Look_In_Primary_Dir : Boolean := True;
   --  GNAT, GNATBIND, GNATMAKE, GNATCLEAN
   --  Set to False if a -I- was present on the command line. When True we are
   --  allowed to look in the primary directory to locate other source or
   --  library files.

   Make_Steps : Boolean := False;
   --  GNATMAKE
   --  Set to True when either Compile_Only, Bind_Only or Link_Only is
   --  set to True.

   Main_Index : Int := 0;
   --  GNATMAKE
   --  This is set to non-zero by gnatmake switch -eInnn to indicate that
   --  the main program is the nnn unit in a multi-unit source file.

   Mapping_File_Name : String_Ptr := null;
   --  GNAT
   --  File name of mapping between unit names, file names and path names.
   --  (given by switch -gnatem)

   Maximum_Messages : Int := 9999;
   --  GNAT, GNATBIND
   --  Maximum default number of errors before compilation is terminated, or in
   --  the case of GNAT, maximum number of warnings before further warnings are
   --  suppressed. Can be overridden by -gnatm (GNAT) or -m (GNATBIND) switch.

   Maximum_File_Name_Length : Int;
   --  GNAT, GNATBIND
   --  Maximum number of characters allowed in a file name, not counting the
   --  extension, as set by the appropriate switch. If no switch is given,
   --  then this value is initialized by Osint to the appropriate value.

   Maximum_Instantiations : Int := 8000;
   --  GNAT
   --  Maximum number of instantiations permitted (to stop runaway cases
   --  of nested instantiations). These situations probably only occur in
   --  specially concocted test cases. Can be modified by -gnateinn switch.

   Maximum_Processes : Positive := 1;
   --  GNATMAKE, GPRBUILD
   --  Maximum number of processes that should be spawned to carry out
   --  compilations.

   Minimal_Recompilation : Boolean := False;
   --  GNATMAKE
   --  Set to True if minimal recompilation mode requested

   Minimize_Expression_With_Actions : Boolean := False;
   --  GNAT
   --  If True, minimize the use of N_Expression_With_Actions node.
   --  This can be used in particular on some back-ends where this node is
   --  difficult to support.

   Modify_Tree_For_C : Boolean := False;
   --  GNAT
   --  If this switch is set True (currently it is set only by -gnatd.V), then
   --  certain meaning-preserving transformations are applied to the tree to
   --  make it easier to interface with back ends that implement C semantics.
   --  There is a section in Sinfo which describes the transformations made.

   Multiple_Unit_Index : Int := 0;
   --  GNAT
   --  This is set non-zero if the current unit is being compiled in multiple
   --  unit per file mode, meaning that the current unit is selected from the
   --  sequence of units in the current source file, using the value stored
   --  in this variable (e.g. 2 = select second unit in file). A value of
   --  zero indicates that we are in normal (one unit per file) mode.

   No_Backup : Boolean := False;
   --  GNATNAME
   --  Do not create backup copies of project files. Set by switch --no-backup.

   No_Deletion : Boolean := False;
   --  GNATPREP
   --  Set by preprocessor switch -a. Do not eliminate any source text. Implies
   --  Undefined_Symbols_Are_False. Useful to perform a syntax check on all
   --  branches of #if constructs.

   No_Elab_Code_All_Pragma : Node_Id := Empty;
   --  Set to point to a No_Elaboration_Code_All pragma or aspect encountered
   --  in the spec of the extended main unit. Used to determine if we need to
   --  do special tests for violation of this aspect.

   No_Main_Subprogram : Boolean := False;
   --  GNATMAKE, GNATBIND
   --  Set to True if compilation/binding of a program without main
   --  subprogram requested.

   No_Run_Time_Mode : Boolean := False;
   --  GNAT, GNATBIND
   --  This flag is set True if a No_Run_Time pragma is encountered. See spec
   --  of Rtsfind for a full description of handling of this pragma.

   No_Split_Units : Boolean := False;
   --  GPRBUILD
   --  Set to True with switch --no-split-units. When True, unit sources, spec,
   --  body and subunits, must all be in the same project. This is checked
   --  after each compilation.

   No_Stdinc : Boolean := False;
   --  GNAT, GNATBIND, GNATMAKE, GNATFIND, GNATXREF
   --  Set to True if no default source search dirs added to search list.

   No_Stdlib : Boolean := False;
   --  GNATMAKE, GNATBIND, GNATFIND, GNATXREF
   --  Set to True if no default library search dirs added to search list.

   No_Strict_Aliasing : Boolean := False;
   --  GNAT
   --  Set True if pragma No_Strict_Aliasing with no parameters encountered.

   No_Tagged_Streams : Node_Id := Empty;
   --  GNAT
   --  If a pragma No_Tagged_Streams is active for the current scope, this
   --  points to the corresponding pragma.

   Normalize_Scalars : Boolean := False;
   --  GNAT, GNATBIND
   --  Set True if a pragma Normalize_Scalars applies to the current unit.
   --  Note that Init_Or_Norm_Scalars is also set to True if this is True.

   Object_Directory_Present : Boolean := False;
   --  GNATMAKE
   --  Set to True when an object directory is specified with option -D

   Object_Path_File_Name : String_Ptr := null;
   --  GNAT2WHY
   --  Path of the temporary file that contains a list of object directories
   --  passed by -gnateO=<obj_path_file>.

   One_Compilation_Per_Obj_Dir : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set to True with switch --single-compile-per-obj-dir. When True, there
   --  cannot be simultaneous compilations with the object files in the same
   --  object directory, if project files are used.

   type Operating_Mode_Type is (Check_Syntax, Check_Semantics, Generate_Code);
   pragma Ordered (Operating_Mode_Type);
   Operating_Mode : Operating_Mode_Type := Generate_Code;
   --  GNAT
   --  Indicates the operating mode of the compiler. The default is generate
   --  code, which runs the parser, semantics and backend. Switches can be
   --  used to set syntax checking only mode, or syntax and semantics checking
   --  only mode. Operating_Mode can also be modified as a result of detecting
   --  errors during the compilation process. In particular if any serious
   --  error is detected then this flag is reset from Generate_Code to
   --  Check_Semantics after generating an error message. This is an ordered
   --  type with the semantics that each value does more than the previous one.

   Optimize_Alignment : Character := 'O';
   --  Setting of Optimize_Alignment, set to T/S/O for time/space/off. Can
   --  be modified by use of pragma Optimize_Alignment.

   Optimize_Alignment_Local : Boolean := False;
   --  Set True if Optimize_Alignment mode is set by a local configuration
   --  pragma that overrides the gnat.adc (or other configuration file) default
   --  so that the unit is not dependent on the default setting. Also always
   --  set True for internal units, since these always have a default setting
   --  of Optimize_Alignment (Off) that is enforced (essentially equivalent to
   --  them all having such an explicit pragma in each unit).

   Original_Operating_Mode : Operating_Mode_Type := Generate_Code;
   --  GNAT
   --  Indicates the original operating mode of the compiler as set by compiler
   --  options. This is identical to Operating_Mode except that this is not
   --  affected by errors.

   Optimization_Level : Int;
   pragma Import (C, Optimization_Level, "optimize");
   --  Constant reflecting the optimization level (0,1,2,3 for -O0,-O1,-O2,-O3)

   Optimize_Size : Int;
   pragma Import (C, Optimize_Size, "optimize_size");
   --  Constant reflecting setting of -Os (optimize for size). Set to nonzero
   --  in -Os mode and set to zero otherwise.

   Output_File_Name_Present : Boolean := False;
   --  GNATBIND, GNAT, GNATMAKE
   --  Set to True when the output C file name is given with option -o for
   --  GNATBIND, when the object file name is given with option -gnatO for GNAT
   --  or when the executable is given with option -o for GNATMAKE.

   Output_Linker_Option_List : Boolean := False;
   --  GNATBIND
   --  True if output of list of linker options is requested (-K switch set)

   Output_ALI_List   : Boolean := False;
   ALI_List_Filename : String_Ptr;
   --  GNATBIND
   --  True if output of list of ALIs is requested (-A switch set). List is
   --  output under the given filename, or standard output if not specified.

   Output_Object_List   : Boolean := False;
   Object_List_Filename : String_Ptr;
   --  GNATBIND
   --  True if output of list of objects is requested (-O switch set). List is
   --  output under the given filename, or standard output if not specified.

   Partition_Elaboration_Policy : Character := ' ';
   --  GNAT, GNATBIND
   --  Set to ' ' for the default case (no elaboration policy specified). Reset
   --  to first character (uppercase) of locking policy name if a valid pragma
   --  Partition_Elaboration_Policy is encountered.

   Partition_Elaboration_Policy_Sloc : Source_Ptr := No_Location;
   --  GNAT, GNATBIND
   --  Remember location of previous Partition_Elaboration_Policy pragma. This
   --  is used for inconsistency error messages. A value of System_Location is
   --  used if the policy is set in package System.

   Persistent_BSS_Mode : Boolean := False;
   --  GNAT
   --  True if a Persistent_BSS configuration pragma is in effect, causing
   --  potentially persistent data to be placed in the persistent_bss section.

   Pessimistic_Elab_Order : Boolean := False;
   --  GNATBIND
   --  True if pessimistic elaboration order is to be chosen (-p switch set)

   Polling_Required : Boolean := False;
   --  GNAT
   --  Set to True if polling for asynchronous abort is enabled by using
   --  the -gnatP option for GNAT.

   Prefix_Exception_Messages : Boolean := False;
   --  GNAT
   --  Set True to prefix exception messages with entity-name:

   Preprocessing_Data_File : String_Ptr := null;
   --  GNAT
   --  Set by switch -gnatep=. The file name of the preprocessing data file.

   Preprocessing_Symbol_Defs : String_List_Access := new String_List (1 .. 4);
   --  An extensible array to temporarily stores symbol definitions specified
   --  on the command line with -gnateD switches. The value 4 is an arbitrary
   --  starting point, if more space is needed it is allocated as required.

   Preprocessing_Symbol_Last : Natural := 0;
   --  Index of last symbol definition in array Symbol_Definitions

   Print_Generated_Code : Boolean := False;
   --  GNAT
   --  Set to True to enable output of generated code in source form. This
   --  flag is set by the -gnatG switch.

   Print_Standard : Boolean := False;
   --  GNAT
   --  Set to true to enable printing of package standard in source form.
   --  This flag is set by the -gnatS switch

   type Usage is (Unknown, Not_In_Use, In_Use);
   Project_File_In_Use : Usage := Unknown;
   --  GNAT
   --  Indicates if a project file is used or not. Set to In_Use by the first
   --  SFNP pragma.

   Queuing_Policy : Character := ' ';
   --  GNAT, GNATBIND
   --  Set to ' ' for the default case (no queuing policy specified). Reset to
   --  first character (uppercase) of locking policy name if a valid
   --  Queuing_Policy pragma is encountered.

   Queuing_Policy_Sloc : Source_Ptr := No_Location;
   --  GNAT, GNATBIND
   --  Remember location of previous Queuing_Policy pragma. This is used for
   --  inconsistency error messages. A value of System_Location is used if the
   --  policy is set in package System.

   Quiet_Output : Boolean := False;
   --  GNATMAKE, GNATCLEAN, GPRBUILD, GPRCLEAN
   --  Set to True if the tool should not have any output if there are no
   --  errors or warnings.

   Overriding_Renamings : Boolean := False;
   --  GNAT
   --  Set to True to enable compatibility mode with Rational compiler, and
   --  to accept renamings of implicit operations in their own scope.

   Relaxed_RM_Semantics : Boolean := False;
   --  GNAT
   --  Set to True to ignore some Ada semantic error to help parse legacy Ada
   --  code for use in e.g. static analysis (such as CodePeer). This deals
   --  with cases where other compilers allow illegal constructs. Tools such as
   --  CodePeer are interested in analyzing code rather than enforcing legality
   --  rules, so as long as these illegal constructs end up with code that can
   --  be handled by the tool in question, there is no reason to reject the
   --  code that is considered correct by the other compiler.

   Replace_In_Comments : Boolean := False;
   --  GNATPREP
   --  Set to True if -C switch used.

   RTS_Lib_Path_Name : String_Ptr := null;
   RTS_Src_Path_Name : String_Ptr := null;
   --  GNAT
   --  Set to the "adalib" and "adainclude" directories of the run time
   --  specified by --RTS=.

   RTS_Switch : Boolean := False;
   --  GNAT, GNATMAKE, GNATBIND, GNATLS, GNATFIND, GNATXREF
   --  Set to True when the --RTS switch is set

   Run_Path_Option : Boolean := True;
   --  GNATMAKE, GNATLINK
   --  Set to False when no run_path_option should be issued to the linker

   Search_Directory_Present : Boolean := False;
   --  GNAT
   --  Set to True when argument is -I. Reset to False when next argument, a
   --  search directory path is taken into account. Note that this is quite
   --  different from other switches in this section in that it is only set in
   --  a transitory manner as a result of scanning a -I switch with no file
   --  name, and if set, is an indication that the next argument is to be
   --  treated as a file name.

   Sec_Stack_Used : Boolean := False;
   --  GNAT, GBATBIND
   --  Set True if generated code uses the System.Secondary_Stack package. For
   --  the binder, set if any unit uses the secondary stack package.

   Setup_Projects : Boolean := False;
   --  GNAT DRIVER
   --  Set to True for GNAT SETUP: the Project Manager creates nonexistent
   --  object, library, and exec directories.

   Shared_Libgnat : Boolean;
   --  GNATBIND
   --  Set to True if a shared libgnat is requested by using the -shared option
   --  for GNATBIND and to False when using the -static option. The value of
   --  this flag is set by Gnatbind.Scan_Bind_Arg.

   Short_Circuit_And_Or : Boolean := False;
   --  GNAT
   --  Set True if a pragma Short_Circuit_And_Or applies to the current unit.

   type SPARK_Mode_Type is (None, Off, On);
   --  Possible legal modes that can be set by aspect/pragma SPARK_Mode, as
   --  well as the value None, which indicates no such pragma/aspect applies.

   SPARK_Mode : SPARK_Mode_Type := None;
   --  GNAT
   --  Current SPARK mode setting.

   SPARK_Mode_Pragma : Node_Id := Empty;
   --  GNAT
   --  If the current SPARK_Mode (above) was set by a pragma, this records
   --  the pragma that set this mode.

   SPARK_Switches_File_Name : String_Ptr := null;
   --  GNAT
   --  Set to non-null file name by use of the -gnates switch to specify
   --  SPARK (gnat2why) specific switches in the given file name.

   Special_Exception_Package_Used : Boolean := False;
   --  GNAT
   --  Set to True if either of the unit GNAT.Most_Recent_Exception or
   --  GNAT.Exception_Traces is with'ed. Used to inhibit transformation of
   --  local raise statements into gotos in the presence of either package.

   Sprint_Line_Limit : Nat := 72;
   --  GNAT
   --  Limit values for chopping long lines in Cprint/Sprint output, can be
   --  reset by use of NNN parameter with -gnatG or -gnatD switches.

   Stack_Checking_Enabled : Boolean := False;
   --  GNAT
   --  Set to indicate if stack checking is enabled for the compilation. This
   --  is set directly from the value in the gcc back end in the body of the
   --  gcc version of back_end.adb.

   Style_Check : Boolean := False;
   --  GNAT
   --  Set True to perform style checks. Activates checks carried out in
   --  package Style (see body of this package for details of checks). This
   --  flag is set True by use of either the -gnatg or -gnaty switches, or
   --  by the Style_Check pragma.

   Style_Check_Main : Boolean := False;
   --  GNAT
   --  Set True if Style_Check was set for the main unit. This is used to
   --  enable style checks for units in the main extended source that get
   --  with'ed indirectly. It is set True by use of either the -gnatg or
   --  -gnaty switches, but not by use of the Style_Checks pragma.

   Disable_FE_Inline        : Boolean := False;
   Disable_FE_Inline_Always : Boolean := False;
   --  GNAT
   --  Request to disable front end inlining from pragma Inline or pragma
   --  Inline_Always out of the presence of the -fno-inline back end flag
   --  on the command line, regardless of any other switches that are set.
   --  It remains the back end's reponsibility to honor -fno-inline at the
   --  back end level.

   Suppress_Control_Flow_Optimizations : Boolean := False;
   --  GNAT
   --  Set by -fpreserve-control-flow. Suppresses control flow optimizations
   --  that interfere with coverage analysis based on the object code.

   System_Extend_Pragma_Arg : Node_Id := Empty;
   --  GNAT
   --  Set non-empty if and only if a correct Extend_System pragma was present
   --  in which case it points to the argument of the pragma, and the name can
   --  be located as Chars (Expression (System_Extend_Pragma_Arg)).

   System_Extend_Unit : Node_Id := Empty;
   --  GNAT
   --  This is set to Empty if GNAT_Mode is set, since pragma Extend_System
   --  is never appropriate in GNAT_Mode (and causes troubles, including
   --  bogus circularities, if we try to compile the run-time library with
   --  a System extension). If GNAT_Mode is not set, then System_Extend_Unit
   --  is a copy of the value set in System_Extend_Pragma_Arg.

   Subunits_Missing : Boolean := False;
   --  GNAT
   --  This flag is set true if missing subunits are detected with code
   --  generation active. This causes code generation to be skipped.

   Suppress_Checks : Boolean := False;
   --  GNAT
   --  Set to True if -gnatp (suppress all checks) switch present.

   Suppress_Options : Suppress_Record;
   --  GNAT
   --  Indicates outer level setting of check suppression. This initializes
   --  the settings of the outer scope level in any unit compiled. This is
   --  initialized by Osint.Initialize, and further initialized by the
   --  Adjust_Global_Switches flag in Gnat1drv.

   Table_Factor : Int := 1;
   --  GNAT
   --  Factor by which all initial table sizes set in Alloc are multiplied.
   --  Used in Table to calculate initial table sizes (the initial table size
   --  is the value in Alloc, used as the Table_Initial parameter value,
   --  multiplied by the factor given here. The default value is used if no
   --  -gnatT switch appears.

   Tagged_Type_Expansion : Boolean := True;
   --  GNAT
   --  Set True if tagged types and interfaces should be expanded by the
   --  front-end. If False, the original tree is left unexpanded for tagged
   --  types and dispatching calls, assuming the underlying target supports it.

   Target_Dependent_Info_Read_Name : String_Ptr := null;
   --  GNAT
   --  Set non-null to override the normal processing in Get_Targ and set the
   --  necessary information by reading the target dependent information file
   --  whose name is given here (see packages Get_Targ and Set_Targ for full
   --  details). Set to non-null file name by use of the -gnateT switch.

   Target_Dependent_Info_Write_Name : String_Ptr := null;
   --  GNAT
   --  Set non-null to enable a call to Set_Targ.Write_Target_Dependent_Info
   --  which writes a target independent information file (see packages
   --  Get_Targ and Set_Targ for full details) using the name given by
   --  this switch. Set to non-null file name by use of the -gnatet switch.

   type Origin_Of_Target is (Unknown, Default, Specified);

   Target_Origin : Origin_Of_Target := Unknown;
   --  GPRBUILD
   --  Indicates the origin of attribute Target in project files

   Target_Value : String_Access := null;
   --  GPRBUILD
   --  Indicates the value of attribute Target in project files

   Task_Dispatching_Policy : Character := ' ';
   --  GNAT, GNATBIND
   --  Set to ' ' for the default case (no task dispatching policy specified).
   --  Reset to first character (uppercase) of task dispatching policy name
   --  if a valid Task_Dispatching_Policy pragma is encountered.

   Task_Dispatching_Policy_Sloc : Source_Ptr := No_Location;
   --  GNAT, GNATBIND
   --  Remember location of previous Task_Dispatching_Policy pragma. This is
   --  used for inconsistency error messages. A value of System_Location is
   --  used if the policy is set in package System.

   Tasking_Used : Boolean := False;
   --  Set True if any tasking construct is encountered. Used to activate the
   --  output of the Q, L and T lines in ALI files.

   Time_Slice_Set : Boolean := False;
   --  GNATBIND
   --  Set True if a pragma Time_Slice is processed in the main unit, or
   --  if the -gnatTnn switch is present to set a time slice value.

   Time_Slice_Value : Nat;
   --  GNATBIND
   --  Time slice value. Valid only if Time_Slice_Set is True, i.e. if
   --  Time_Slice pragma has been processed. Set to the time slice value in
   --  microseconds. Negative values are stored as zero, and the value is not
   --  larger than 1_000_000_000 (1000 seconds). Values larger than this are
   --  reset to this maximum. This can also be set with the -gnatTnn switch.

   Tolerate_Consistency_Errors : Boolean := False;
   --  GNATBIND
   --  Tolerate time stamp and other consistency errors. If this flag is set to
   --  True (-t), then inconsistencies result in warnings rather than errors.

   Treat_Categorization_Errors_As_Warnings : Boolean := False;
   --  Normally categorization errors are true illegalities. If this switch
   --  is set, then such errors result in warning messages rather than error
   --  messages. Set True by -gnateP (P for Pure/Preelaborate). Also set in
   --  Relaxed_RM_Semantics mode since some old Ada 83 compilers treated
   --  pragma Preelaborate differently.

   Treat_Restrictions_As_Warnings : Boolean := False;
   --  GNAT
   --  Set True to treat pragma Restrictions as Restriction_Warnings. Set by
   --  -gnatr switch.

   Tree_Output : Boolean := False;
   --  GNAT
   --  Set to True (-gnatt) to generate output tree file

   Try_Semantics : Boolean := False;
   --  GNAT
   --  Flag set to force attempt at semantic analysis, even if parser errors
   --  occur. This will probably cause blowups at this stage in the game. On
   --  the other hand, most such blowups will be caught cleanly and simply
   --  say compilation abandoned. This flag is set True by -gnatq or -gnatQ.

   Unchecked_Shared_Lib_Imports : Boolean := False;
   --  GPRBUILD
   --  Set to True when shared library projects are allowed to import projects
   --  that are not shared library projects. Set on by use of the switch
   --  --unchecked-shared-lib-imports.

   Undefined_Symbols_Are_False : Boolean := False;
   --  GNAT, GNATPREP
   --  Set to True by switch -u of gnatprep or -u in the preprocessing data
   --  file for the compiler. Indicates that while preprocessing sources,
   --  symbols that are not defined have the value FALSE.

   Uneval_Old : Character := 'E';
   --  GNAT
   --  Set to 'E'/'W'/'A' for use of Error/Warn/Allow in a valid pragma
   --  Unevaluated_Use_Of_Old. Default in the absence of the pragma is 'E'
   --  for the RM default behavior of giving an error.

   Unique_Error_Tag : Boolean := Tag_Errors;
   --  GNAT
   --  Indicates if error messages are to be prefixed by the string error:
   --  Initialized from Tag_Errors, can be forced on with the -gnatU switch.

   Unnest_Subprogram_Mode : Boolean := False;
   --  If true, activates the circuitry for unnesting subprograms (see the spec
   --  of Exp_Unst for full details). Currently set only by use of -gnatd.1.

   Unreserve_All_Interrupts : Boolean := False;
   --  GNAT, GNATBIND
   --  Normally set False, set True if a valid Unreserve_All_Interrupts pragma
   --  appears anywhere in the main unit for GNAT, or if any ALI file has the
   --  corresponding attribute set in GNATBIND.

   Upper_Half_Encoding : Boolean := False;
   --  GNAT, GNATBIND
   --  Normally set False, indicating that upper half ISO 8859-1 characters are
   --  used in the normal way to represent themselves. If the wide character
   --  encoding method uses the upper bit for this encoding, then this flag is
   --  set True, and upper half characters in the source indicate the start of
   --  a wide character sequence. Set by -gnatW or -W switches.

   Use_Include_Path_File : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  When True, create a source search path file, even when a mapping file
   --  is used.

   Usage_Requested : Boolean := False;
   --  GNAT, GNATBIND, GNATMAKE
   --  Set to True if -h (-gnath for the compiler) switch encountered
   --  requesting usage information

   Use_Pragma_Linker_Constructor : Boolean := False;
   --  GNATBIND
   --  True if pragma Linker_Constructor applies to adainit

   Use_VADS_Size : Boolean := False;
   --  GNAT
   --  Set to True if a valid pragma Use_VADS_Size is processed

   Validity_Checks_On  : Boolean := True;
   --  GNAT
   --  This flag determines if validity checking is on or off. The initial
   --  state is on, and the required default validity checks are active. The
   --  actual set of checks that is performed if Validity_Checks_On is set is
   --  defined by the switches in package Validsw. The Validity_Checks_On flag
   --  is controlled by pragma Validity_Checks (On | Off), and also some
   --  generated compiler code (typically code that has to do with validity
   --  check generation) is compiled with this flag set to False. This flag is
   --  set to False by the -gnatp switch.

   Verbose_Mode : Boolean := False;
   --  GNAT, GNATBIND, GNATMAKE, GNATLINK, GNATLS, GNATNAME, GNATCLEAN,
   --  GPRBUILD, GPRCLEAN
   --  Set to True to get verbose mode (full error message text and location
   --  information sent to standard output, also header, copyright and summary)

   type Verbosity_Level_Type is (None, Low, Medium, High);
   pragma Ordered (Verbosity_Level_Type);
   Verbosity_Level : Verbosity_Level_Type := High;
   --  GNATMAKE
   --  Modified by gnatmake switches -v, -vl, -vm, -vh. Indicates
   --  the level of verbosity of informational messages:
   --
   --  In Low Verbosity, the reasons why a source is recompiled, the name
   --  of the executable and the reason it must be rebuilt is output.
   --
   --  In Medium Verbosity, additional lines are output for each ALI file
   --  that is checked.
   --
   --  In High Verbosity, additional lines are output when the ALI file
   --  is part of an Ada library, is read-only or is part of the runtime.

   Warn_On_Ada_2005_Compatibility : Boolean := True;
   --  GNAT
   --  Set to True to generate all warnings on Ada 2005 compatibility issues,
   --  including warnings on Ada 2005 obsolescent features used in Ada 2005
   --  mode. Set by default, modified by use of -gnatwy/Y.

   Warn_On_Ada_2012_Compatibility : Boolean := True;
   --  GNAT
   --  Set to True to generate all warnings on Ada 2012 compatibility issues,
   --  including warnings on Ada 2012 obsolescent features used in Ada 2012
   --  mode. Modified by use of -gnatwy/Y.

   Warn_On_All_Unread_Out_Parameters : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings in all cases where a variable is
   --  modified by being passed as to an OUT formal, but the resulting value is
   --  never read. The default is that this warning is suppressed. Modified
   --  by use of gnatw.o/.O.

   Warn_On_Assertion_Failure : Boolean := True;
   --  GNAT
   --  Set to True to activate warnings on assertions that can be determined
   --  at compile time will always fail. Modified by use of -gnatw.a/.A.

   Warn_On_Assumed_Low_Bound : Boolean := True;
   --  GNAT
   --  Set to True to activate warnings for string parameters that are indexed
   --  with literals or S'Length, presumably assuming a lower bound of one.
   --  Modified by use of -gnatww/W.

   Warn_On_Atomic_Synchronization : Boolean := False;
   --  GNAT
   --  Set to True to generate information messages for atomic synchronization.
   --  Modified by use of -gnatw.n/.N.

   Warn_On_Bad_Fixed_Value : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for static fixed-point expression
   --  values that are not an exact multiple of the small value of the type.
   --  Odd by default, modified by use of -gnatwb/B.

   Warn_On_Biased_Representation : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for size clauses, component clauses
   --  and component_size clauses that force biased representation. Modified
   --  by use of -gnatw.b/.B.

   Warn_On_Constant : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for variables that could be declared
   --  as constants. Modified by use of -gnatwk/K.

   Warn_On_Deleted_Code : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for code deleted by the front end
   --  for conditional statements whose outcome is known at compile time.
   --  Modified by use of -gnatwt/T.

   Warn_On_Dereference : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for implicit dereferences for array
   --  indexing and record component access. Modified by use of -gnatwd/D.

   Warn_On_Export_Import : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for suspicious use of export or
   --  import pragmas. Modified by use of -gnatwx/X.

   Warn_On_Elab_Access : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for P'Access in the case where
   --  subprogram P is in the same package as the P'Access, and the P'Access is
   --  evaluated at package elaboration time, and occurs before the body of P
   --  has been elaborated.

   Warn_On_Hiding : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings if a declared entity hides another
   --  entity. The default is that this warning is suppressed. Modified by
   --  use of -gnatwh/H.

   Warn_On_Modified_Unread : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings if a variable is assigned but is never
   --  read. Also controls warnings for similar cases involving out parameters,
   --  but only if there is only one out parameter for the procedure involved.
   --  The default is that this warning is suppressed, modified by use of
   --  -gnatwm/M.

   Warn_On_No_Value_Assigned : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings if no value is ever assigned to a
   --  variable that is at least partially uninitialized. Set to false to
   --  suppress such warnings. The default is that such warnings are enabled.
   --  Modified by use of -gnatwv/V.

   Warn_On_Non_Local_Exception : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for non-local exception raises and also
   --  handlers that can never handle a local raise. This warning is only ever
   --  generated if pragma Restrictions (No_Exception_Propagation) is set. The
   --  default is not to generate the warnings except that if the source has
   --  at least one exception handler, and this restriction is set, and the
   --  warning was not explicitly turned off, then it is turned on by default.
   --  Modified by use of -gnatw.x/.X.

   No_Warn_On_Non_Local_Exception : Boolean := False;
   --  GNAT
   --  This is set to True if the above warning is explicitly suppressed. We
   --  use this to avoid turning it on by default when No_Exception_Propagation
   --  restriction is set and an exception handler is present.

   Warn_On_Object_Renames_Function : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings when a function result is renamed as
   --  an object. The default is that this warning is disabled. Modified by
   --  use of -gnatw.r/.R.

   Warn_On_Obsolescent_Feature : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings on use of any feature in Annex or if a
   --  subprogram is called for which a pragma Obsolescent applies. Modified
   --  by use of -gnatwj/J.

   Warn_On_Overlap : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings when a writable actual overlaps with
   --  another actual in a subprogram call. This applies only in modes before
   --  Ada 2012. Starting with Ada 2012, such overlaps are illegal.
   --  Modified by use of -gnatw.i/.I.

   Warn_On_Questionable_Missing_Parens : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for cases where parentheses are missing
   --  and the usage is questionable, because the intent is unclear. On by
   --  default, modified by use of -gnatwq/Q.

   Warn_On_Parameter_Order : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for cases where the argument list for
   --  a call is a sequence of identifiers that match the formal identifiers,
   --  but are in the wrong order.

   Warn_On_Redundant_Constructs : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for redundant constructs (e.g. useless
   --  assignments/conversions). The default is that this warning is disabled.
   --  Modified by use of -gnatwr/R.

   Warn_On_Reverse_Bit_Order : Boolean := True;
   --  GNAT
   --  Set to True to generate warning (informational) messages for component
   --  clauses that are affected by non-standard bit-order. The default is
   --  that this warning is enabled. Modified by -gnatw.v/.V.

   Warn_On_Suspicious_Contract : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for suspicious contracts expressed as
   --  pragmas or aspects precondition and postcondition, as well as other
   --  suspicious cases of expressions typically found in contracts like
   --  quantified expressions and uses of Update attribute. The default is that
   --  this warning is enabled. Modified by use of -gnatw.t/.T.

   Warn_On_Suspicious_Modulus_Value : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for suspicious modulus values. The
   --  default is that this warning is enabled. Modified by -gnatw.m/.M.

   Warn_On_Unchecked_Conversion : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for unchecked conversions that may have
   --  non-portable semantics (e.g. because sizes of types differ). Modified
   --  by use of -gnatwz/Z.

   Warn_On_Unordered_Enumeration_Type : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for inappropriate uses (comparisons
   --  and explicit ranges) on unordered enumeration types (which includes
   --  all enumeration types for which pragma Ordered is not given). The
   --  default is that this warning is disabled. Modified by -gnat.u/.U.

   Warn_On_Unrecognized_Pragma : Boolean := True;
   --  GNAT
   --  Set to True to generate warnings for unrecognized pragmas. The default
   --  is that this warning is enabled. Modified by use of -gnatwg/G.

   Warn_On_Unrepped_Components : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for the case of components of record
   --  which have a record representation clause but this component does not
   --  have a component clause. Modified by use of -gnatw.c/.C.

   Warn_On_Warnings_Off : Boolean := False;
   --  GNAT
   --  Set to True to generate warnings for use of Pragma Warnings (Off, ent),
   --  where either the pragma is never used, or it could be replaced by a
   --  pragma Unmodified or Unreferenced. Also generates warnings for pragma
   --  Warning (Off, string) which either has no matching pragma Warning On,
   --  or where no warning has been suppressed by the use of the pragma.
   --  Modified by use of -gnatw.w/.W.

   type Warning_Mode_Type is (Suppress, Normal, Treat_As_Error);
   Warning_Mode : Warning_Mode_Type := Normal;
   --  GNAT, GNATBIND
   --  Controls treatment of warning messages. If set to Suppress, warning
   --  messages are not generated at all. In Normal mode, they are generated
   --  but do not count as errors. In Treat_As_Error mode, warning messages are
   --  generated and are treated as errors. Note that Warning_Mode = Suppress
   --  causes pragma Warnings to be ignored (except for legality checks),
   --  unless we are in GNATprove_Mode, which requires pragma Warnings to
   --  be stored for the formal verification backend.

   Warnings_As_Errors_Count : Natural;
   --  GNAT
   --  Number of entries stored in Warnings_As_Errors table

   Wide_Character_Encoding_Method : WC_Encoding_Method := WCEM_Brackets;
   --  GNAT, GNATBIND
   --  Method used for encoding wide characters in the source program. See
   --  description of type in unit System.WCh_Con for a list of the methods
   --  that are currently supported. Note that brackets notation is always
   --  recognized in source programs regardless of the setting of this
   --  variable. The default setting causes only the brackets notation to be
   --  recognized. If this is the main unit, this setting also controls the
   --  output of the W=? parameter in the ALI file, which is used to provide
   --  the default for encoding [Wide_[Wide_]]Text_IO files. For the binder,
   --  the value set here overrides this main unit default.

   Wide_Character_Encoding_Method_Specified : Boolean := False;
   --  GNAT, GNATBIND
   --  Set True if the value in Wide_Character_Encoding_Method was set as
   --  a result of an explicit -gnatW? or -W? switch. False otherwise.

   Xref_Active : Boolean := True;
   --  GNAT
   --  Set if cross-referencing is enabled (i.e. xref info in ALI files)

   Zero_Formatting : Boolean := False;
   --  GNATBIND
   --  Do no formatting (no title, no leading spaces, no empty lines) in
   --  auxiliary outputs (-e, -K, -l, -R).

   ----------------------------
   -- Configuration Settings --
   ----------------------------

   --  These are settings that are used to establish the mode at the start of
   --  each unit. The values defined below can be affected either by command
   --  line switches, or by the use of appropriate configuration pragmas in a
   --  configuration pragma file (but NOT by a local use of a configuration
   --  pragma in a single file).

   Ada_Version_Config : Ada_Version_Type;
   --  GNAT
   --  This is the value of the configuration switch for the Ada 83 mode, as
   --  set by the command line switches -gnat83/95/2005/2012, and possibly
   --  modified by the use of configuration pragmas Ada_*. This switch is used
   --  to set the initial value for Ada_Version mode at the start of analysis
   --  of a unit.  Note however that the setting of this flag is ignored for
   --  internal and predefined units (which are always compiled in the most up
   --  to date version of Ada).

   Ada_Version_Pragma_Config : Node_Id;
   --  This will be set nonempty if it is set by a configuration pragma

   Ada_Version_Explicit_Config : Ada_Version_Type;
   --  GNAT
   --  This is set in the same manner as Ada_Version_Config. The difference is
   --  that the setting of this flag is not ignored for internal and predefined
   --  units, which for some purposes do indeed access this value, regardless
   --  of the fact that they are compiled the most up to date ada version).

   Assertions_Enabled_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch for assertions enabled
   --  mode, as possibly set by the command line switch -gnata, and possibly
   --  modified by the use of the configuration pragma Assertion_Policy.

   Assume_No_Invalid_Values_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch for assuming "no invalid
   --  values enabled" mode, as possibly set by the command line switch
   --  -gnatB, and possibly modified by the use of the configuration pragma
   --  Assume_No_Invalid_Values.

   Check_Float_Overflow_Config : Boolean;
   --  GNAT
   --  Set to True to check that operations on predefined unconstrained float
   --  types (e.g. Float, Long_Float) do not overflow and generate infinities
   --  or invalid values. Set by the Check_Float_Overflow pragma, or by use
   --  of the -gnateF switch.

   Check_Policy_List_Config : Node_Id;
   --  GNAT
   --  This points to the list of N_Pragma nodes for Check_Policy pragmas
   --  that are linked through the Next_Pragma fields, with the list being
   --  terminated by Empty. The order is most recently processed first. This
   --  list includes only those pragmas in configuration pragma files.

   Default_Pool_Config : Node_Id := Empty;
   --  GNAT
   --  Same as Default_Pool above, except this is only for Default_Storage_Pool
   --  pragmas that are configuration pragmas.

   Default_SSO_Config : Character := ' ';
   --  GNAT
   --  Set if a pragma Default_Scalar_Storage_Order appears as a configuration
   --  pragma. A value of ' ' means that no pragma was given, otherwise the
   --  value is 'H' for High_Order_First or 'L' for Low_Order_First.

   Dynamic_Elaboration_Checks_Config : Boolean := False;
   --  GNAT
   --  Set True for dynamic elaboration checking mode, as set by the -gnatE
   --  switch or by the use of pragma Elaboration_Checking (Dynamic).

   Exception_Locations_Suppressed_Config : Boolean := False;
   --  GNAT
   --  Set True by use of the configuration pragma Suppress_Exception_Messages

   Extensions_Allowed_Config : Boolean;
   --  GNAT
   --  This is the flag that indicates whether extensions are allowed. It can
   --  be set True either by use of the -gnatX switch, or by use of the
   --  configuration pragma Extensions_Allowed (On). It is always set to True
   --  for internal GNAT units, since extensions are always permitted in such
   --  units.

   External_Name_Exp_Casing_Config : External_Casing_Type;
   --  GNAT
   --  This is the value of the configuration switch that controls casing of
   --  external symbols for which an explicit external name is given. It can be
   --  set to Uppercase by the command line switch -gnatF, and further modified
   --  by the use of the configuration pragma External_Name_Casing in the
   --  gnat.adc file. This flag is used to set the initial value for
   --  External_Name_Exp_Casing at the start of analyzing each unit. Note
   --  however that the setting of this flag is ignored for internal and
   --  predefined units (which are always compiled with As_Is mode).

   External_Name_Imp_Casing_Config : External_Casing_Type;
   --  GNAT
   --  This is the value of the configuration switch that controls casing of
   --  external symbols where the external name is implicitly given. It can be
   --  set to Uppercase by the command line switch -gnatF, and further modified
   --  by the use of the configuration pragma External_Name_Casing in the
   --  gnat.adc file. This flag is used to set the initial value for
   --  External_Name_Imp_Casing at the start of analyzing each unit. Note
   --  however that the setting of this flag is ignored for internal and
   --  predefined units (which are always compiled with Lowercase mode).

   Fast_Math_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch that controls Fast_Math
   --  mode, as set by a Fast_Math pragma in configuration pragmas. It is
   --  used to set the initial value of Fast_Math at the start of each new
   --  compilation unit.

   Initialize_Scalars_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch that is set by the
   --  pragma Initialize_Scalars when it appears in the gnat.adc file.
   --  This switch is not set when the pragma appears ahead of a given
   --  unit, so it does not affect the compilation of other units.

   No_Exit_Message : Boolean := False;
   --  GNATMAKE, GPRBUILD
   --  Set with switch --no-exit-message. When True, if there are compilation
   --  failures, the builder does not issue an exit error message.

   Optimize_Alignment_Config : Character;
   --  GNAT
   --  This is the value of the configuration switch that controls the
   --  alignment optimization mode, as set by an Optimize_Alignment pragma.
   --  It is used to set the initial value of Optimize_Alignment at the start
   --  of each new compilation unit, except that it is always set to 'O' (off)
   --  for internal units.

   Persistent_BSS_Mode_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch that controls whether
   --  potentially persistent data is to be placed in the persistent_bss
   --  section. It can be set True by use of the pragma Persistent_BSS.
   --  This flag is used to set the initial value of Persistent_BSS_Mode
   --  at the start of each compilation unit, except that it is always
   --  set False for predefined units.

   Polling_Required_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch that controls polling
   --  mode. It can be set True by the command line switch -gnatP, and then
   --  further modified by the use of pragma Polling in the gnat.adc file. This
   --  flag is used to set the initial value for Polling_Required at the start
   --  of analyzing each unit.

   Prefix_Exception_Messages_Config : Boolean;
   --  The setting of Prefix_Exception_Messages from configuration pragmas

   SPARK_Mode_Config : SPARK_Mode_Type := None;
   --  GNAT
   --  The setting of SPARK_Mode from configuration pragmas

   SPARK_Mode_Pragma_Config : Node_Id := Empty;
   --  If a SPARK_Mode pragma appeared in the configuration pragmas (setting
   --  SPARK_Mode_Config appropriately), then this points to the N_Pragma node.

   Uneval_Old_Config : Character;
   --  GNAT
   --  The setting of Uneval_Old from configuration pragmas

   Use_VADS_Size_Config : Boolean;
   --  GNAT
   --  This is the value of the configuration switch that controls the use of
   --  VADS_Size instead of Size wherever the attribute Size is used. It can
   --  be set True by the use of the pragma Use_VADS_Size in the gnat.adc file.
   --  This flag is used to set the initial value for Use_VADS_Size at the
   --  start of analyzing each unit. Note however that the setting of this flag
   --  is ignored for internal and predefined units (which are always compiled
   --  with the standard Size semantics).

   Warnings_As_Errors_Count_Config : Natural;
   --  GNAT
   --  Count of pattern strings stored from Warning_As_Error pragmas

   type Config_Switches_Type is private;
   --  Type used to save values of the switches set from Config values

   procedure Save_Opt_Config_Switches (Save : out Config_Switches_Type);
   --  This procedure saves the current values of the switches which are
   --  initialized from the above Config values, and then resets these switches
   --  according to the Config value settings.

   procedure Set_Opt_Config_Switches
     (Internal_Unit : Boolean;
      Main_Unit     : Boolean);
   --  This procedure sets the switches to the appropriate initial values. The
   --  parameter Internal_Unit is True for an internal or predefined unit, and
   --  affects the way the switches are set (see above). Main_Unit is true if
   --  switches are being set for the main unit or for the spec of the main
   --  unit. This affects setting of the assert/debug pragma switches, which
   --  are normally set false by default for an internal unit, except when the
   --  internal unit is the main unit, in which case we use the command line
   --  settings.

   procedure Restore_Opt_Config_Switches (Save : Config_Switches_Type);
   --  This procedure restores a set of switch values previously saved by a
   --  call to Save_Opt_Config_Switches (Save).

   procedure Register_Opt_Config_Switches;
   --  This procedure is called after processing the gnat.adc file and other
   --  configuration pragma files to record the values of the Config switches,
   --  as possibly modified by the use of command line switches and pragmas
   --  appearing in these files.

   ------------------------
   -- Other Global Flags --
   ------------------------

   Expander_Active : Boolean := False;
   --  A flag that indicates if expansion is active (True) or deactivated
   --  (False). When expansion is deactivated all calls to expander routines
   --  have no effect. Note that the initial setting of False is merely to
   --  prevent saving of an undefined value for an initial call to the
   --  Expander_Mode_Save_And_Set procedure. For more information on the use of
   --  this flag, see package Expander. Indeed this flag might more logically
   --  be in the spec of Expander, but it is referenced by Errout, and it
   --  really seems wrong for Errout to depend on Expander.

   Static_Dispatch_Tables : Boolean := True;
   --  This flag indicates if the backend supports generation of statically
   --  allocated dispatch tables. If it is True, then the front end will
   --  generate static aggregates for dispatch tables that contain forward
   --  references to addresses of subprograms not seen yet, and the back end
   --  must be prepared to handle this case. If it is False, then the front
   --  end generates assignments to initialize the dispatch table, and there
   --  are no such forward references. By default we build statically allocated
   --  dispatch tables for all library level tagged types in all platforms.This
   --  behavior can be disabled using switch -gnatd.t which will set this flag
   --  to False and revert to the previous dynamic behavior.

   -----------------------
   -- Tree I/O Routines --
   -----------------------

   procedure Tree_Read;
   --  Reads switch settings from current tree file using Tree_Read

   procedure Tree_Write;
   --  Writes out switch settings to current tree file using Tree_Write

   --------------------------
   -- ASIS Version Control --
   --------------------------

   --  These two variables (Tree_Version_String and Tree_ASIS_Version_Number)
   --  are supposed to be used in the GNAT/ASIS version check performed in
   --  the ASIS code (this package is also a part of the ASIS implementation).
   --  They are set by Tree_Read procedure, so they represent the version
   --  number (and the version string) of the compiler which has created the
   --  tree, and they are supposed to be compared with the corresponding values
   --  from the Tree_IO and Gnatvsn packages which also are a part of ASIS
   --  implementation.

   Tree_Version_String : String_Access;
   --  Used to store the compiler version string read from a tree file to check
   --  if it is from the same date as stored in the version string in Gnatvsn.
   --  We require that ASIS Pro can be used only with GNAT Pro, but we allow
   --  non-Pro ASIS and ASIS-based tools to be used with any version of the
   --  GNAT compiler. Therefore, we need the possibility to compare the dates
   --  of the corresponding source sets, using version strings that may be
   --  of different lengths.

   Tree_ASIS_Version_Number : Int;
   --  Used to store the ASIS version number read from a tree file to check if
   --  it is the same as stored in the ASIS version number in Tree_IO.

   -----------------------------------
   -- Modes for Formal Verification --
   -----------------------------------

   GNATprove_Mode : Boolean := False;
   --  Specific compiling mode targeting formal verification for those parts
   --  of the input code that belong to the SPARK 2014 subset of Ada. Set True
   --  by the gnat2why executable or by use of the -gnatd.F debug switch. Note
   --  that this is completely separate from the SPARK restriction defined in
   --  GNAT to detect violations of a subset of SPARK 2005 rules.

   ---------------------------
   -- Error/Warning Control --
   ---------------------------

   --  The following array would more reasonably be located in Err_Vars or
   --  Errour, but we put them here to deal with licensing issues (we need
   --  this to have the GPL exception licensing, since these variables and
   --  subprograms are accessed from units with this licensing).

   Warnings_As_Errors : array (1 .. 10_000) of String_Ptr;
   --  Table for recording Warning_As_Error pragmas as they are processed.
   --  It would be nicer to use Table, but there are circular elaboration
   --  problems if we try to do this, and an attempt to find some other
   --  appropriately licensed unit to declare this as a Table failed with
   --  various elaboration circularities. Memory is getting cheap these days!

   ---------------
   -- GNAT_Mode --
   ---------------

   GNAT_Mode : Boolean := False;
   --  GNAT
   --  True if compiling in GNAT system mode (-gnatg switch)

   GNAT_Mode_Config : Boolean := False;
   --  GNAT
   --  True if -gnatg switch is present. GNAT_Mode may be temporary set to
   --  True during the analysis of a system unit, but GNAT_Mode_Config must
   --  not change once scanned and set.

   --  Setting GNAT mode has the following effects on the language that is
   --  accepted. Note that several of the following have the effect of changing
   --  an error to a warning. But warnings are usually treated as fatal errors
   --  in -gnatg mode, so to actually take advantage of such a change, it is
   --  necessary to add an explicit pragma Warnings (Off) in the source and
   --  this requires clear documentation of why this is necessary.

   --    The identifier character set is set to 'n' (7-bit ASCII)

   --    Pragma Extend_System is ignored

   --    Warning_Mode is set to Treat_As_Error (-gnatwe)

   --    Standard style checks are set (See Set_GNAT_Style_Check_Options)

   --    Standard warnings are turned on (see Set_GNAT_Mode_Warnings)

   --    The Ada version is set to Ada 2012

   --    Task priorities are always allowed to be in the range Any_Priority

   --    Overflow checks are suppressed, overflow checking set to strict mode

   --    ALI files are always generated for predefined generic packages

   --    Obsolescent feature warnings are suppressed

   --    Recompilation of children of GNAT, System, Ada, Interfaces is allowed

   --    The Scalar_Storage_Order attribute applies to generic types

   --    Categorization errors are treated as warnings rather than errors

   --    Statements in preelaborated units give warnings rather than errors

   --    Private objects are allowed in preelaborated units

   --    Non-static constants in preelaborated units give warnings not errors

   --    The warning about component size being ignored is suppressed

   --    The warning about size clauses being ignored is suppressed

   --    Initializing limited types gives a warning rather than an error

   --    Copying of limited objects is allowed

   --    Returning objects of limited types is allowed

   --    Non-static call in preelaborated unit give a warning, not an error

   --    Warnings on possible elaboration errors are suppressed

   --    Warnings about packing being ignored are suppressed

   --    Warnings in internal units are not suppressed (they normally are)

   --    The only special comment sequence allowed is --!

   --------------------------
   -- Private Declarations --
   --------------------------

private

   --  The following type is used to save and restore settings of switches in
   --  Opt that represent the configuration (i.e. result of config pragmas).

   --  Note that Ada_Version_Explicit is not included, since this is a sticky
   --  flag that once set does not get reset, since the whole idea of this flag
   --  is to record the setting for the main unit.

   type Config_Switches_Type is record
      Ada_Version                    : Ada_Version_Type;
      Ada_Version_Explicit           : Ada_Version_Type;
      Ada_Version_Pragma             : Node_Id;
      Assertions_Enabled             : Boolean;
      Assume_No_Invalid_Values       : Boolean;
      Check_Float_Overflow           : Boolean;
      Check_Policy_List              : Node_Id;
      Default_Pool                   : Node_Id;
      Default_SSO                    : Character;
      Dynamic_Elaboration_Checks     : Boolean;
      Exception_Locations_Suppressed : Boolean;
      Extensions_Allowed             : Boolean;
      External_Name_Exp_Casing       : External_Casing_Type;
      External_Name_Imp_Casing       : External_Casing_Type;
      Fast_Math                      : Boolean;
      Initialize_Scalars             : Boolean;
      Normalize_Scalars              : Boolean;
      Optimize_Alignment             : Character;
      Optimize_Alignment_Local       : Boolean;
      Persistent_BSS_Mode            : Boolean;
      Polling_Required               : Boolean;
      Prefix_Exception_Messages      : Boolean;
      SPARK_Mode                     : SPARK_Mode_Type;
      SPARK_Mode_Pragma              : Node_Id;
      Uneval_Old                     : Character;
      Use_VADS_Size                  : Boolean;
      Warnings_As_Errors_Count       : Natural;
   end record;

   --  The following declarations are for GCC version dependent flags. We do
   --  not let client code in the compiler test GCC_Version directly, but
   --  instead use deferred constants for relevant feature tags.

   --  Note: there currently are no such constants defined in this section,
   --  since the compiler front end is currently entirely independent of the
   --  GCC version, which is a desirable state of affairs.

   function get_gcc_version return Int;
   pragma Import (C, get_gcc_version, "get_gcc_version");

   GCC_Version : constant Nat := get_gcc_version;
   --  GNATMAKE
   --  Indicates which version of gcc is in use (3 = 3.x, 4 = 4.x). Note that
   --  gcc 2.8.1 (which used to be a value of 2) is no longer supported.

end Opt;