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
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
|
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- E X P _ C H 5 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2024, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Accessibility; use Accessibility;
with Aspects; use Aspects;
with Atree; use Atree;
with Checks; use Checks;
with Debug; use Debug;
with Einfo; use Einfo;
with Einfo.Entities; use Einfo.Entities;
with Einfo.Utils; use Einfo.Utils;
with Elists; use Elists;
with Exp_Aggr; use Exp_Aggr;
with Exp_Ch6; use Exp_Ch6;
with Exp_Ch7; use Exp_Ch7;
with Exp_Ch11; use Exp_Ch11;
with Exp_Dbug; use Exp_Dbug;
with Exp_Pakd; use Exp_Pakd;
with Exp_Tss; use Exp_Tss;
with Exp_Util; use Exp_Util;
with Inline; use Inline;
with Mutably_Tagged; use Mutably_Tagged;
with Namet; use Namet;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sinfo; use Sinfo;
with Sinfo.Nodes; use Sinfo.Nodes;
with Sinfo.Utils; use Sinfo.Utils;
with Sem; use Sem;
with Sem_Aux; use Sem_Aux;
with Sem_Ch3; use Sem_Ch3;
with Sem_Ch8; use Sem_Ch8;
with Sem_Ch13; use Sem_Ch13;
with Sem_Eval; use Sem_Eval;
with Sem_Res; use Sem_Res;
with Sem_Util; use Sem_Util;
use Sem_Util.Storage_Model_Support;
with Snames; use Snames;
with Stand; use Stand;
with Stringt; use Stringt;
with Tbuild; use Tbuild;
with Ttypes; use Ttypes;
with Uintp; use Uintp;
with Validsw; use Validsw;
with Warnsw; use Warnsw;
package body Exp_Ch5 is
procedure Build_Formal_Container_Iteration
(N : Node_Id;
Container : Entity_Id;
Cursor : Entity_Id;
Init : out Node_Id;
Advance : out Node_Id;
New_Loop : out Node_Id);
-- Utility to create declarations and loop statement for both forms
-- of formal container iterators.
function Convert_To_Iterable_Type
(Container : Entity_Id;
Loc : Source_Ptr) return Node_Id;
-- Returns New_Occurrence_Of (Container), possibly converted to an ancestor
-- type, if the type of Container inherited the Iterable aspect from that
-- ancestor.
function Change_Of_Representation (N : Node_Id) return Boolean;
-- Determine if the right-hand side of assignment N is a type conversion
-- which requires a change of representation. Called only for the array
-- and record cases.
procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id);
-- N is an assignment which assigns an array value. This routine process
-- the various special cases and checks required for such assignments,
-- including change of representation. Rhs is normally simply the right-
-- hand side of the assignment, except that if the right-hand side is a
-- type conversion or a qualified expression, then the RHS is the actual
-- expression inside any such type conversions or qualifications.
function Expand_Assign_Array_Loop
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Ndim : Pos;
Rev : Boolean) return Node_Id;
-- N is an assignment statement which assigns an array value. This routine
-- expands the assignment into a loop (or nested loops for the case of a
-- multi-dimensional array) to do the assignment component by component.
-- Larray and Rarray are the entities of the actual arrays on the left-hand
-- and right-hand sides. L_Type and R_Type are the types of these arrays
-- (which may not be the same, due to either sliding, or to a change of
-- representation case). Ndim is the number of dimensions and the parameter
-- Rev indicates if the loops run normally (Rev = False), or reversed
-- (Rev = True). The value returned is the constructed loop statement.
-- Auxiliary declarations are inserted before node N using the standard
-- Insert_Actions mechanism.
function Expand_Assign_Array_Bitfield
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Rev : Boolean) return Node_Id;
-- Alternative to Expand_Assign_Array_Loop for packed bitfields. Generates
-- a call to System.Bitfields.Copy_Bitfield, which is more efficient than
-- copying component-by-component.
function Expand_Assign_Array_Bitfield_Fast
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id) return Node_Id;
-- Alternative to Expand_Assign_Array_Bitfield. Generates a call to
-- System.Bitfields.Fast_Copy_Bitfield, which is more efficient than
-- Copy_Bitfield, but only works in restricted situations.
function Expand_Assign_Array_Loop_Or_Bitfield
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Ndim : Pos;
Rev : Boolean) return Node_Id;
-- Calls either Expand_Assign_Array_Loop, Expand_Assign_Array_Bitfield, or
-- Expand_Assign_Array_Bitfield_Fast as appropriate.
procedure Expand_Assign_Record (N : Node_Id);
-- N is an assignment of an untagged record value. This routine handles
-- the case where the assignment must be made component by component,
-- either because the target is not byte aligned, or there is a change
-- of representation, or when we have a tagged type with a representation
-- clause (this last case is required because holes in the tagged type
-- might be filled with components from child types).
procedure Expand_Assign_With_Target_Names (N : Node_Id);
-- (AI12-0125): N is an assignment statement whose RHS contains occurrences
-- of @ that designate the value of the LHS of the assignment. If the LHS
-- is side-effect-free the target names can be replaced with a copy of the
-- LHS; otherwise the semantics of the assignment is described in terms of
-- a procedure with an in-out parameter, and expanded as such.
procedure Expand_Formal_Container_Loop (N : Node_Id);
-- Use the primitives specified in an Iterable aspect to expand a loop
-- over a so-called formal container, primarily for SPARK usage.
procedure Expand_Formal_Container_Element_Loop (N : Node_Id);
-- Same, for an iterator of the form " For E of C". In this case the
-- iterator provides the name of the element, and the cursor is generated
-- internally.
procedure Expand_Iterator_Loop (N : Node_Id);
-- Expand loop over arrays and containers that uses the form "for X of C"
-- with an optional subtype mark, or "for Y in C".
procedure Expand_Iterator_Loop_Over_Container
(N : Node_Id;
I_Spec : Node_Id;
Container : Node_Id;
Container_Typ : Entity_Id);
-- Expand loop over containers that uses the form "for X of C" with an
-- optional subtype mark, or "for Y in C". I_Spec is the iterator
-- specification and Container is either the Container (for OF) or the
-- iterator (for IN).
procedure Expand_Predicated_Loop (N : Node_Id);
-- Expand for loop over predicated subtype
function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id;
-- Generate the necessary code for controlled and tagged assignment, that
-- is to say, finalization of the target before, adjustment of the target
-- after and save and restore of the tag and finalization pointers which
-- are not 'part of the value' and must not be changed upon assignment. N
-- is the original Assignment node.
--------------------------------------
-- Build_Formal_Container_Iteration --
--------------------------------------
procedure Build_Formal_Container_Iteration
(N : Node_Id;
Container : Entity_Id;
Cursor : Entity_Id;
Init : out Node_Id;
Advance : out Node_Id;
New_Loop : out Node_Id)
is
Loc : constant Source_Ptr := Sloc (N);
Stats : constant List_Id := Statements (N);
Typ : constant Entity_Id := Base_Type (Etype (Container));
Has_Element_Op : constant Entity_Id :=
Get_Iterable_Type_Primitive (Typ, Name_Has_Element);
First_Op : Entity_Id;
Next_Op : Entity_Id;
begin
-- Use the proper set of primitives depending on the direction of
-- iteration. The legality of a reverse iteration has been checked
-- during analysis.
if Reverse_Present (Iterator_Specification (Iteration_Scheme (N))) then
First_Op := Get_Iterable_Type_Primitive (Typ, Name_Last);
Next_Op := Get_Iterable_Type_Primitive (Typ, Name_Previous);
else
First_Op := Get_Iterable_Type_Primitive (Typ, Name_First);
Next_Op := Get_Iterable_Type_Primitive (Typ, Name_Next);
end if;
-- Declaration for Cursor
Init :=
Make_Object_Declaration (Loc,
Defining_Identifier => Cursor,
Object_Definition => New_Occurrence_Of (Etype (First_Op), Loc),
Expression =>
Make_Function_Call (Loc,
Name => New_Occurrence_Of (First_Op, Loc),
Parameter_Associations => New_List (
Convert_To_Iterable_Type (Container, Loc))));
-- Statement that advances (in the right direction) cursor in loop
Advance :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Cursor, Loc),
Expression =>
Make_Function_Call (Loc,
Name => New_Occurrence_Of (Next_Op, Loc),
Parameter_Associations => New_List (
Convert_To_Iterable_Type (Container, Loc),
New_Occurrence_Of (Cursor, Loc))));
-- Iterator is rewritten as a while_loop
New_Loop :=
Make_Loop_Statement (Loc,
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Condition =>
Make_Function_Call (Loc,
Name => New_Occurrence_Of (Has_Element_Op, Loc),
Parameter_Associations => New_List (
Convert_To_Iterable_Type (Container, Loc),
New_Occurrence_Of (Cursor, Loc)))),
Statements => Stats,
End_Label => Empty);
-- If the contruct has a specified loop name, preserve it in the new
-- loop, for possible use in exit statements.
if Present (Identifier (N))
and then Comes_From_Source (Identifier (N))
then
Set_Identifier (New_Loop, Identifier (N));
end if;
end Build_Formal_Container_Iteration;
------------------------------
-- Change_Of_Representation --
------------------------------
function Change_Of_Representation (N : Node_Id) return Boolean is
Rhs : constant Node_Id := Expression (N);
begin
return
Nkind (Rhs) = N_Type_Conversion
and then not Has_Compatible_Representation
(Target_Typ => Etype (Rhs),
Operand_Typ => Etype (Expression (Rhs)));
end Change_Of_Representation;
------------------------------
-- Convert_To_Iterable_Type --
------------------------------
function Convert_To_Iterable_Type
(Container : Entity_Id;
Loc : Source_Ptr) return Node_Id
is
Typ : constant Entity_Id := Base_Type (Etype (Container));
Aspect : constant Node_Id := Find_Aspect (Typ, Aspect_Iterable);
Result : Node_Id;
begin
Result := New_Occurrence_Of (Container, Loc);
if Entity (Aspect) /= Typ then
Result :=
Make_Type_Conversion (Loc,
Subtype_Mark => New_Occurrence_Of (Entity (Aspect), Loc),
Expression => Result);
end if;
return Result;
end Convert_To_Iterable_Type;
-------------------------
-- Expand_Assign_Array --
-------------------------
-- There are two issues here. First, do we let Gigi do a block move, or
-- do we expand out into a loop? Second, we need to set the two flags
-- Forwards_OK and Backwards_OK which show whether the block move (or
-- corresponding loops) can be legitimately done in a forwards (low to
-- high) or backwards (high to low) manner.
procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Lhs : constant Node_Id := Name (N);
Act_Lhs : constant Node_Id := Get_Referenced_Object (Lhs);
Act_Rhs : Node_Id := Get_Referenced_Object (Rhs);
L_Type : constant Entity_Id :=
Underlying_Type (Get_Actual_Subtype (Act_Lhs));
R_Type : Entity_Id :=
Underlying_Type (Get_Actual_Subtype (Act_Rhs));
L_Slice : constant Boolean := Nkind (Act_Lhs) = N_Slice;
R_Slice : constant Boolean := Nkind (Act_Rhs) = N_Slice;
Crep : constant Boolean := Change_Of_Representation (N);
pragma Assert
(Crep
or else Is_Bit_Packed_Array (L_Type) = Is_Bit_Packed_Array (R_Type));
Larray : Node_Id;
Rarray : Node_Id;
Ndim : constant Pos := Number_Dimensions (L_Type);
Loop_Required : Boolean := False;
-- This switch is set to True if the array move must be done using
-- an explicit front end generated loop.
procedure Apply_Dereference (Arg : Node_Id);
-- If the argument is an access to an array, and the assignment is
-- converted into a procedure call, apply explicit dereference.
function Has_Address_Clause (Exp : Node_Id) return Boolean;
-- Test if Exp is a reference to an array whose declaration has
-- an address clause, or it is a slice of such an array.
function Is_Formal_Array (Exp : Node_Id) return Boolean;
-- Test if Exp is a reference to an array which is either a formal
-- parameter or a slice of a formal parameter. These are the cases
-- where hidden aliasing can occur.
function Is_Non_Local_Array (Exp : Node_Id) return Boolean;
-- Determine if Exp is a reference to an array variable which is other
-- than an object defined in the current scope, or a component or a
-- slice of such an object. Such objects can be aliased to parameters
-- (unlike local array references).
-----------------------
-- Apply_Dereference --
-----------------------
procedure Apply_Dereference (Arg : Node_Id) is
Typ : constant Entity_Id := Etype (Arg);
begin
if Is_Access_Type (Typ) then
Rewrite (Arg, Make_Explicit_Dereference (Loc,
Prefix => Relocate_Node (Arg)));
Analyze_And_Resolve (Arg, Designated_Type (Typ));
end if;
end Apply_Dereference;
------------------------
-- Has_Address_Clause --
------------------------
function Has_Address_Clause (Exp : Node_Id) return Boolean is
begin
return
(Is_Entity_Name (Exp) and then
Present (Address_Clause (Entity (Exp))))
or else
(Nkind (Exp) = N_Slice and then Has_Address_Clause (Prefix (Exp)));
end Has_Address_Clause;
---------------------
-- Is_Formal_Array --
---------------------
function Is_Formal_Array (Exp : Node_Id) return Boolean is
begin
return
(Is_Entity_Name (Exp) and then Is_Formal (Entity (Exp)))
or else
(Nkind (Exp) = N_Slice and then Is_Formal_Array (Prefix (Exp)));
end Is_Formal_Array;
------------------------
-- Is_Non_Local_Array --
------------------------
function Is_Non_Local_Array (Exp : Node_Id) return Boolean is
begin
case Nkind (Exp) is
when N_Indexed_Component
| N_Selected_Component
| N_Slice
=>
return Is_Non_Local_Array (Prefix (Exp));
when others =>
return
not (Is_Entity_Name (Exp)
and then Scope (Entity (Exp)) = Current_Scope);
end case;
end Is_Non_Local_Array;
-- Determine if Lhs, Rhs are formal arrays or nonlocal arrays
Lhs_Formal : constant Boolean := Is_Formal_Array (Act_Lhs);
Rhs_Formal : constant Boolean := Is_Formal_Array (Act_Rhs);
Lhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Lhs);
Rhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Rhs);
-- Start of processing for Expand_Assign_Array
begin
-- Deal with length check. Note that the length check is done with
-- respect to the right-hand side as given, not a possible underlying
-- renamed object, since this would generate incorrect extra checks.
Apply_Length_Check_On_Assignment (Rhs, L_Type, Lhs);
-- We start by assuming that the move can be done in either direction,
-- i.e. that the two sides are completely disjoint.
Set_Forwards_OK (N, True);
Set_Backwards_OK (N, True);
-- Normally it is only the slice case that can lead to overlap, and
-- explicit checks for slices are made below. But there is one case
-- where the slice can be implicit and invisible to us: when we have a
-- one dimensional array, and either both operands are parameters, or
-- one is a parameter (which can be a slice passed by reference) and the
-- other is a non-local variable. In this case the parameter could be a
-- slice that overlaps with the other operand.
-- However, if the array subtype is a constrained first subtype in the
-- parameter case, then we don't have to worry about overlap, since
-- slice assignments aren't possible (other than for a slice denoting
-- the whole array).
-- Note: No overlap is possible if there is a change of representation,
-- so we can exclude this case.
if Ndim = 1
and then not Crep
and then
((Lhs_Formal and Rhs_Formal)
or else
(Lhs_Formal and Rhs_Non_Local_Var)
or else
(Rhs_Formal and Lhs_Non_Local_Var))
and then
(not Is_Constrained (Etype (Lhs))
or else not Is_First_Subtype (Etype (Lhs)))
then
Set_Forwards_OK (N, False);
Set_Backwards_OK (N, False);
-- Note: the bit-packed case is not worrisome here, since if we have
-- a slice passed as a parameter, it is always aligned on a byte
-- boundary, and if there are no explicit slices, the assignment
-- can be performed directly.
end if;
-- If either operand has an address clause clear Backwards_OK and
-- Forwards_OK, since we cannot tell if the operands overlap. We
-- exclude this treatment when Rhs is an aggregate, since we know
-- that overlap can't occur.
if (Has_Address_Clause (Lhs) and then Nkind (Rhs) /= N_Aggregate)
or else Has_Address_Clause (Rhs)
then
Set_Forwards_OK (N, False);
Set_Backwards_OK (N, False);
end if;
-- We certainly must use a loop for change of representation and also
-- we use the operand of the conversion on the right-hand side as the
-- effective right-hand side (the component types must match in this
-- situation).
if Crep then
Act_Rhs := Get_Referenced_Object (Rhs);
R_Type := Get_Actual_Subtype (Act_Rhs);
Loop_Required := True;
-- We require a loop if either side is possibly bit aligned
elsif Possible_Bit_Aligned_Component (Lhs)
or else
Possible_Bit_Aligned_Component (Rhs)
then
Loop_Required := True;
-- Arrays with controlled components are expanded into a loop to force
-- calls to Adjust at the component level.
elsif Has_Controlled_Component (L_Type) then
Loop_Required := True;
-- If object is full access, we cannot tolerate a loop
elsif Is_Full_Access_Object (Act_Lhs)
or else
Is_Full_Access_Object (Act_Rhs)
then
return;
-- Loop is required if we have atomic components since we have to
-- be sure to do any accesses on an element by element basis.
elsif Has_Atomic_Components (L_Type)
or else Has_Atomic_Components (R_Type)
or else Is_Full_Access (Component_Type (L_Type))
or else Is_Full_Access (Component_Type (R_Type))
then
Loop_Required := True;
-- Case where no slice is involved
elsif not L_Slice and not R_Slice then
-- The following code deals with the case of unconstrained bit packed
-- arrays. The problem is that the template for such arrays contains
-- the bounds of the actual source level array, but the copy of an
-- entire array requires the bounds of the underlying array. It would
-- be nice if the back end could take care of this, but right now it
-- does not know how, so if we have such a type, then we expand out
-- into a loop, which is inefficient but works correctly. If we don't
-- do this, we get the wrong length computed for the array to be
-- moved. The two cases we need to worry about are:
-- Explicit dereference of an unconstrained packed array type as in
-- the following example:
-- procedure C52 is
-- type BITS is array(INTEGER range <>) of BOOLEAN;
-- pragma PACK(BITS);
-- type A is access BITS;
-- P1,P2 : A;
-- begin
-- P1 := new BITS (1 .. 65_535);
-- P2 := new BITS (1 .. 65_535);
-- P2.ALL := P1.ALL;
-- end C52;
-- A formal parameter reference with an unconstrained bit array type
-- is the other case we need to worry about (here we assume the same
-- BITS type declared above):
-- procedure Write_All (File : out BITS; Contents : BITS);
-- begin
-- File.Storage := Contents;
-- end Write_All;
-- We expand to a loop in either of these two cases
-- Question for future thought. Another potentially more efficient
-- approach would be to create the actual subtype, and then do an
-- unchecked conversion to this actual subtype ???
Check_Unconstrained_Bit_Packed_Array : declare
function Is_UBPA_Reference (Opnd : Node_Id) return Boolean;
-- Function to perform required test for the first case, above
-- (dereference of an unconstrained bit packed array).
-----------------------
-- Is_UBPA_Reference --
-----------------------
function Is_UBPA_Reference (Opnd : Node_Id) return Boolean is
Typ : constant Entity_Id := Underlying_Type (Etype (Opnd));
P_Type : Entity_Id;
Des_Type : Entity_Id;
begin
if Present (Packed_Array_Impl_Type (Typ))
and then Is_Array_Type (Packed_Array_Impl_Type (Typ))
and then not Is_Constrained (Packed_Array_Impl_Type (Typ))
then
return True;
elsif Nkind (Opnd) = N_Explicit_Dereference then
P_Type := Underlying_Type (Etype (Prefix (Opnd)));
if not Is_Access_Type (P_Type) then
return False;
else
Des_Type := Designated_Type (P_Type);
return
Is_Bit_Packed_Array (Des_Type)
and then not Is_Constrained (Des_Type);
end if;
else
return False;
end if;
end Is_UBPA_Reference;
-- Start of processing for Check_Unconstrained_Bit_Packed_Array
begin
if Is_UBPA_Reference (Lhs)
or else
Is_UBPA_Reference (Rhs)
then
Loop_Required := True;
-- Here if we do not have the case of a reference to a bit packed
-- unconstrained array case. In this case gigi can most certainly
-- handle the assignment if a forwards move is allowed.
-- (could it handle the backwards case also???)
elsif Forwards_OK (N) then
return;
end if;
end Check_Unconstrained_Bit_Packed_Array;
-- The back end can always handle the assignment if the right side is a
-- string literal (note that overlap is definitely impossible in this
-- case). If the type is packed, a string literal is always converted
-- into an aggregate, except in the case of a null slice, for which no
-- aggregate can be written. In that case, rewrite the assignment as a
-- null statement, a length check has already been emitted to verify
-- that the range of the left-hand side is empty.
-- Note that this code is not executed if we have an assignment of a
-- string literal to a non-bit aligned component of a record, a case
-- which cannot be handled by the backend.
elsif Nkind (Rhs) = N_String_Literal then
if String_Length (Strval (Rhs)) = 0
and then Is_Bit_Packed_Array (L_Type)
then
Rewrite (N, Make_Null_Statement (Loc));
Analyze (N);
end if;
return;
-- If either operand is bit packed, then we need a loop, since we can't
-- be sure that the slice is byte aligned.
elsif Is_Bit_Packed_Array (L_Type)
or else Is_Bit_Packed_Array (R_Type)
then
Loop_Required := True;
-- If we are not bit-packed, and we have only one slice, then no overlap
-- is possible except in the parameter case, so we can let the back end
-- handle things.
elsif not (L_Slice and R_Slice) then
if Forwards_OK (N) then
return;
end if;
end if;
-- If the right-hand side is a string literal, introduce a temporary for
-- it, for use in the generated loop that will follow.
if Nkind (Rhs) = N_String_Literal then
declare
Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Rhs);
Decl : Node_Id;
begin
Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Temp,
Object_Definition => New_Occurrence_Of (L_Type, Loc),
Expression => Relocate_Node (Rhs));
Insert_Action (N, Decl);
Rewrite (Rhs, New_Occurrence_Of (Temp, Loc));
R_Type := Etype (Temp);
end;
end if;
-- Come here to complete the analysis
-- Loop_Required: Set to True if we know that a loop is required
-- regardless of overlap considerations.
-- Forwards_OK: Set to False if we already know that a forwards
-- move is not safe, else set to True.
-- Backwards_OK: Set to False if we already know that a backwards
-- move is not safe, else set to True
-- Our task at this stage is to complete the overlap analysis, which can
-- result in possibly setting Forwards_OK or Backwards_OK to False, and
-- then generating the final code, either by deciding that it is OK
-- after all to let Gigi handle it, or by generating appropriate code
-- in the front end.
declare
L_Index_Typ : constant Entity_Id := Etype (First_Index (L_Type));
R_Index_Typ : constant Entity_Id := Etype (First_Index (R_Type));
Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ);
Left_Hi : constant Node_Id := Type_High_Bound (L_Index_Typ);
Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ);
Right_Hi : constant Node_Id := Type_High_Bound (R_Index_Typ);
Act_L_Array : Node_Id;
Act_R_Array : Node_Id;
Cleft_Lo : Node_Id;
Cright_Lo : Node_Id;
Condition : Node_Id;
Cresult : Compare_Result;
begin
-- Get the expressions for the arrays. If we are dealing with a
-- private type, then convert to the underlying type. We can do
-- direct assignments to an array that is a private type, but we
-- cannot assign to elements of the array without this extra
-- unchecked conversion.
-- Note: We propagate Parent to the conversion nodes to generate
-- a well-formed subtree.
if Nkind (Act_Lhs) = N_Slice then
Larray := Prefix (Act_Lhs);
else
Larray := Act_Lhs;
if Is_Private_Type (Etype (Larray)) then
declare
Par : constant Node_Id := Parent (Larray);
begin
Larray :=
Unchecked_Convert_To
(Underlying_Type (Etype (Larray)), Larray);
Set_Parent (Larray, Par);
end;
end if;
end if;
if Nkind (Act_Rhs) = N_Slice then
Rarray := Prefix (Act_Rhs);
else
Rarray := Act_Rhs;
if Is_Private_Type (Etype (Rarray)) then
declare
Par : constant Node_Id := Parent (Rarray);
begin
Rarray :=
Unchecked_Convert_To
(Underlying_Type (Etype (Rarray)), Rarray);
Set_Parent (Rarray, Par);
end;
end if;
end if;
-- If both sides are slices, we must figure out whether it is safe
-- to do the move in one direction or the other. It is always safe
-- if there is a change of representation since obviously two arrays
-- with different representations cannot possibly overlap.
if not Crep and L_Slice and R_Slice then
Act_L_Array := Get_Referenced_Object (Prefix (Act_Lhs));
Act_R_Array := Get_Referenced_Object (Prefix (Act_Rhs));
-- If both left- and right-hand arrays are entity names, and refer
-- to different entities, then we know that the move is safe (the
-- two storage areas are completely disjoint).
if Is_Entity_Name (Act_L_Array)
and then Is_Entity_Name (Act_R_Array)
and then Entity (Act_L_Array) /= Entity (Act_R_Array)
then
null;
-- Otherwise, we assume the worst, which is that the two arrays
-- are the same array. There is no need to check if we know that
-- is the case, because if we don't know it, we still have to
-- assume it.
-- Generally if the same array is involved, then we have an
-- overlapping case. We will have to really assume the worst (i.e.
-- set neither of the OK flags) unless we can determine the lower
-- or upper bounds at compile time and compare them.
else
Cresult :=
Compile_Time_Compare
(Left_Lo, Right_Lo, Assume_Valid => True);
if Cresult = Unknown then
Cresult :=
Compile_Time_Compare
(Left_Hi, Right_Hi, Assume_Valid => True);
end if;
case Cresult is
when EQ | LE | LT =>
Set_Backwards_OK (N, False);
when GE | GT =>
Set_Forwards_OK (N, False);
when NE | Unknown =>
Set_Backwards_OK (N, False);
Set_Forwards_OK (N, False);
end case;
end if;
end if;
-- If after that analysis Loop_Required is False, meaning that we
-- have not discovered some non-overlap reason for requiring a loop,
-- then the outcome depends on the capabilities of the back end.
if not Loop_Required then
-- Assume the back end can deal with all cases of overlap by
-- falling back to memmove if it cannot use a more efficient
-- approach.
return;
end if;
-- At this stage we have to generate an explicit loop, and we have
-- the following cases:
-- Forwards_OK = True
-- Rnn : right_index := right_index'First;
-- for Lnn in left-index loop
-- left (Lnn) := right (Rnn);
-- Rnn := right_index'Succ (Rnn);
-- end loop;
-- Note: the above code MUST be analyzed with checks off, because
-- otherwise the Succ could overflow. But in any case this is more
-- efficient.
-- Forwards_OK = False, Backwards_OK = True
-- Rnn : right_index := right_index'Last;
-- for Lnn in reverse left-index loop
-- left (Lnn) := right (Rnn);
-- Rnn := right_index'Pred (Rnn);
-- end loop;
-- Note: the above code MUST be analyzed with checks off, because
-- otherwise the Pred could overflow. But in any case this is more
-- efficient.
-- Forwards_OK = Backwards_OK = False
-- This only happens if we have the same array on each side. It is
-- possible to create situations using overlays that violate this,
-- but we simply do not promise to get this "right" in this case.
-- There are two possible subcases. If the No_Implicit_Conditionals
-- restriction is set, then we generate the following code:
-- declare
-- T : constant <operand-type> := rhs;
-- begin
-- lhs := T;
-- end;
-- If implicit conditionals are permitted, then we generate:
-- if Left_Lo <= Right_Lo then
-- <code for Forwards_OK = True above>
-- else
-- <code for Backwards_OK = True above>
-- end if;
-- In order to detect possible aliasing, we examine the renamed
-- expression when the source or target is a renaming. However,
-- the renaming may be intended to capture an address that may be
-- affected by subsequent code, and therefore we must recover
-- the actual entity for the expansion that follows, not the
-- object it renames. In particular, if source or target designate
-- a portion of a dynamically allocated object, the pointer to it
-- may be reassigned but the renaming preserves the proper location.
if Is_Entity_Name (Rhs)
and then
Nkind (Parent (Entity (Rhs))) = N_Object_Renaming_Declaration
and then Nkind (Act_Rhs) = N_Slice
then
Rarray := Rhs;
end if;
if Is_Entity_Name (Lhs)
and then
Nkind (Parent (Entity (Lhs))) = N_Object_Renaming_Declaration
and then Nkind (Act_Lhs) = N_Slice
then
Larray := Lhs;
end if;
-- Cases where either Forwards_OK or Backwards_OK is true
if Forwards_OK (N) or else Backwards_OK (N) then
if Needs_Finalization (Component_Type (L_Type))
and then Base_Type (L_Type) = Base_Type (R_Type)
and then Ndim = 1
and then not No_Ctrl_Actions (N)
and then not No_Finalize_Actions (N)
then
declare
Proc : constant Entity_Id :=
TSS (Base_Type (L_Type), TSS_Slice_Assign);
Actuals : List_Id;
begin
Apply_Dereference (Larray);
Apply_Dereference (Rarray);
Actuals := New_List (
Duplicate_Subexpr (Larray, Name_Req => True),
Duplicate_Subexpr (Rarray, Name_Req => True),
Duplicate_Subexpr (Left_Lo, Name_Req => True),
Duplicate_Subexpr (Left_Hi, Name_Req => True),
Duplicate_Subexpr (Right_Lo, Name_Req => True),
Duplicate_Subexpr (Right_Hi, Name_Req => True));
Append_To (Actuals,
New_Occurrence_Of (
Boolean_Literals (not Forwards_OK (N)), Loc));
Rewrite (N,
Make_Procedure_Call_Statement (Loc,
Name => New_Occurrence_Of (Proc, Loc),
Parameter_Associations => Actuals));
end;
else
Rewrite (N,
Expand_Assign_Array_Loop_Or_Bitfield
(N, Larray, Rarray, L_Type, R_Type, Ndim,
Rev => not Forwards_OK (N)));
end if;
-- Case of both are false with No_Implicit_Conditionals
elsif Restriction_Active (No_Implicit_Conditionals) then
declare
T : constant Entity_Id :=
Make_Defining_Identifier (Loc, Chars => Name_T);
begin
Rewrite (N,
Make_Block_Statement (Loc,
Declarations => New_List (
Make_Object_Declaration (Loc,
Defining_Identifier => T,
Constant_Present => True,
Object_Definition =>
New_Occurrence_Of (Etype (Rhs), Loc),
Expression => Relocate_Node (Rhs))),
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (
Make_Assignment_Statement (Loc,
Name => Relocate_Node (Lhs),
Expression => New_Occurrence_Of (T, Loc))))));
end;
-- Case of both are false with implicit conditionals allowed
else
-- Before we generate this code, we must ensure that the left and
-- right side array types are defined. They may be itypes, and we
-- cannot let them be defined inside the if, since the first use
-- in the then may not be executed.
Ensure_Defined (L_Type, N);
Ensure_Defined (R_Type, N);
-- We normally compare addresses to find out which way round to
-- do the loop, since this is reliable, and handles the cases of
-- parameters, conversions etc. But we can't do that in the bit
-- packed case, because addresses don't work there.
if not Is_Bit_Packed_Array (L_Type) then
Condition :=
Make_Op_Le (Loc,
Left_Opnd =>
Unchecked_Convert_To (RTE (RE_Integer_Address),
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr_Move_Checks (Larray, True),
Expressions => New_List (
Make_Attribute_Reference (Loc,
Prefix =>
New_Occurrence_Of
(L_Index_Typ, Loc),
Attribute_Name => Name_First))),
Attribute_Name => Name_Address)),
Right_Opnd =>
Unchecked_Convert_To (RTE (RE_Integer_Address),
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr_Move_Checks (Rarray, True),
Expressions => New_List (
Make_Attribute_Reference (Loc,
Prefix =>
New_Occurrence_Of
(R_Index_Typ, Loc),
Attribute_Name => Name_First))),
Attribute_Name => Name_Address)));
-- For the bit packed and VM cases we use the bounds. That's OK,
-- because we don't have to worry about parameters, since they
-- cannot cause overlap. Perhaps we should worry about weird slice
-- conversions ???
else
-- Copy the bounds
Cleft_Lo := New_Copy_Tree (Left_Lo);
Cright_Lo := New_Copy_Tree (Right_Lo);
-- If the types do not match we add an implicit conversion
-- here to ensure proper match
if Etype (Left_Lo) /= Etype (Right_Lo) then
Cright_Lo :=
Unchecked_Convert_To (Etype (Left_Lo), Cright_Lo);
end if;
-- Reset the Analyzed flag, because the bounds of the index
-- type itself may be universal, and must be reanalyzed to
-- acquire the proper type for the back end.
Set_Analyzed (Cleft_Lo, False);
Set_Analyzed (Cright_Lo, False);
Condition :=
Make_Op_Le (Loc,
Left_Opnd => Cleft_Lo,
Right_Opnd => Cright_Lo);
end if;
if Needs_Finalization (Component_Type (L_Type))
and then Base_Type (L_Type) = Base_Type (R_Type)
and then Ndim = 1
and then not No_Ctrl_Actions (N)
and then not No_Finalize_Actions (N)
then
-- Call TSS procedure for array assignment, passing the
-- explicit bounds of right- and left-hand sides.
declare
Proc : constant Entity_Id :=
TSS (Base_Type (L_Type), TSS_Slice_Assign);
Actuals : List_Id;
begin
Apply_Dereference (Larray);
Apply_Dereference (Rarray);
Actuals := New_List (
Duplicate_Subexpr (Larray, Name_Req => True),
Duplicate_Subexpr (Rarray, Name_Req => True),
Duplicate_Subexpr (Left_Lo, Name_Req => True),
Duplicate_Subexpr (Left_Hi, Name_Req => True),
Duplicate_Subexpr (Right_Lo, Name_Req => True),
Duplicate_Subexpr (Right_Hi, Name_Req => True));
Append_To (Actuals,
Make_Op_Not (Loc,
Right_Opnd => Condition));
Rewrite (N,
Make_Procedure_Call_Statement (Loc,
Name => New_Occurrence_Of (Proc, Loc),
Parameter_Associations => Actuals));
end;
else
Rewrite (N,
Make_Implicit_If_Statement (N,
Condition => Condition,
Then_Statements => New_List (
Expand_Assign_Array_Loop_Or_Bitfield
(N, Larray, Rarray, L_Type, R_Type, Ndim,
Rev => False)),
Else_Statements => New_List (
Expand_Assign_Array_Loop_Or_Bitfield
(N, Larray, Rarray, L_Type, R_Type, Ndim,
Rev => True))));
end if;
end if;
Analyze (N, Suppress => All_Checks);
end;
exception
when RE_Not_Available =>
return;
end Expand_Assign_Array;
------------------------------
-- Expand_Assign_Array_Loop --
------------------------------
-- The following is an example of the loop generated for the case of a
-- two-dimensional array:
-- declare
-- R2b : Tm1X1 := 1;
-- begin
-- for L1b in 1 .. 100 loop
-- declare
-- R4b : Tm1X2 := 1;
-- begin
-- for L3b in 1 .. 100 loop
-- vm1 (L1b, L3b) := vm2 (R2b, R4b);
-- R4b := Tm1X2'succ(R4b);
-- end loop;
-- end;
-- R2b := Tm1X1'succ(R2b);
-- end loop;
-- end;
-- Here Rev is False, and Tm1Xn are the subscript types for the right-hand
-- side. The declarations of R2b and R4b are inserted before the original
-- assignment statement.
function Expand_Assign_Array_Loop
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Ndim : Pos;
Rev : Boolean) return Node_Id
is
Loc : constant Source_Ptr := Sloc (N);
Lnn : array (1 .. Ndim) of Entity_Id;
Rnn : array (1 .. Ndim) of Entity_Id;
-- Entities used as subscripts on left and right sides
L_Index_Type : array (1 .. Ndim) of Entity_Id;
R_Index_Type : array (1 .. Ndim) of Entity_Id;
-- Left and right index types
Assign : Node_Id;
F_Or_L : Name_Id;
S_Or_P : Name_Id;
function Build_Step (J : Nat) return Node_Id;
-- The increment step for the index of the right-hand side is written
-- as an attribute reference (Succ or Pred). This function returns
-- the corresponding node, which is placed at the end of the loop body.
----------------
-- Build_Step --
----------------
function Build_Step (J : Nat) return Node_Id is
Step : Node_Id;
Lim : Name_Id;
begin
if Rev then
Lim := Name_First;
else
Lim := Name_Last;
end if;
Step :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Rnn (J), Loc),
Expression =>
Make_Attribute_Reference (Loc,
Prefix =>
New_Occurrence_Of (R_Index_Type (J), Loc),
Attribute_Name => S_Or_P,
Expressions => New_List (
New_Occurrence_Of (Rnn (J), Loc))));
-- Note that on the last iteration of the loop, the index is increased
-- (or decreased) past the corresponding bound. This is consistent with
-- the C semantics of the back-end, where such an off-by-one value on a
-- dead index variable is OK. However, in CodePeer mode this leads to
-- spurious warnings, and thus we place a guard around the attribute
-- reference. For obvious reasons we only do this for CodePeer.
if CodePeer_Mode then
Step :=
Make_If_Statement (Loc,
Condition =>
Make_Op_Ne (Loc,
Left_Opnd => New_Occurrence_Of (Lnn (J), Loc),
Right_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => New_Occurrence_Of (L_Index_Type (J), Loc),
Attribute_Name => Lim)),
Then_Statements => New_List (Step));
end if;
return Step;
end Build_Step;
-- Start of processing for Expand_Assign_Array_Loop
begin
if Rev then
F_Or_L := Name_Last;
S_Or_P := Name_Pred;
else
F_Or_L := Name_First;
S_Or_P := Name_Succ;
end if;
-- Setup index types and subscript entities
declare
L_Index : Node_Id;
R_Index : Node_Id;
begin
L_Index := First_Index (L_Type);
R_Index := First_Index (R_Type);
for J in 1 .. Ndim loop
Lnn (J) := Make_Temporary (Loc, 'L');
Rnn (J) := Make_Temporary (Loc, 'R');
L_Index_Type (J) := Etype (L_Index);
R_Index_Type (J) := Etype (R_Index);
Next_Index (L_Index);
Next_Index (R_Index);
end loop;
end;
-- Now construct the assignment statement
declare
ExprL : constant List_Id := New_List;
ExprR : constant List_Id := New_List;
begin
for J in 1 .. Ndim loop
Append_To (ExprL, New_Occurrence_Of (Lnn (J), Loc));
Append_To (ExprR, New_Occurrence_Of (Rnn (J), Loc));
end loop;
Assign :=
Make_Assignment_Statement (Loc,
Name =>
Make_Indexed_Component (Loc,
Prefix => Duplicate_Subexpr (Larray, Name_Req => True),
Expressions => ExprL),
Expression =>
Make_Indexed_Component (Loc,
Prefix => Duplicate_Subexpr (Rarray, Name_Req => True),
Expressions => ExprR));
-- We set assignment OK, since there are some cases, e.g. in object
-- declarations, where we are actually assigning into a constant.
-- If there really is an illegality, it was caught long before now,
-- and was flagged when the original assignment was analyzed.
Set_Assignment_OK (Name (Assign));
-- Propagate the No_{Ctrl,Finalize}_Actions flags to assignments
Set_No_Ctrl_Actions (Assign, No_Ctrl_Actions (N));
Set_No_Finalize_Actions (Assign, No_Finalize_Actions (N));
end;
-- Now construct the loop from the inside out, with the last subscript
-- varying most rapidly. Note that Assign is first the raw assignment
-- statement, and then subsequently the loop that wraps it up.
for J in reverse 1 .. Ndim loop
Assign :=
Make_Block_Statement (Loc,
Declarations => New_List (
Make_Object_Declaration (Loc,
Defining_Identifier => Rnn (J),
Object_Definition =>
New_Occurrence_Of (R_Index_Type (J), Loc),
Expression =>
Make_Attribute_Reference (Loc,
Prefix => New_Occurrence_Of (R_Index_Type (J), Loc),
Attribute_Name => F_Or_L))),
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (
Make_Implicit_Loop_Statement (N,
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification (Loc,
Defining_Identifier => Lnn (J),
Reverse_Present => Rev,
Discrete_Subtype_Definition =>
New_Occurrence_Of (L_Index_Type (J), Loc))),
Statements => New_List (Assign, Build_Step (J))))));
end loop;
return Assign;
end Expand_Assign_Array_Loop;
----------------------------------
-- Expand_Assign_Array_Bitfield --
----------------------------------
function Expand_Assign_Array_Bitfield
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Rev : Boolean) return Node_Id
is
pragma Assert (not Rev);
-- Reverse copying is not yet supported by Copy_Bitfield.
pragma Assert (not Change_Of_Representation (N));
-- This won't work, for example, to copy a packed array to an unpacked
-- array.
Loc : constant Source_Ptr := Sloc (N);
L_Index_Typ : constant Entity_Id := Etype (First_Index (L_Type));
R_Index_Typ : constant Entity_Id := Etype (First_Index (R_Type));
Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ);
Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ);
L_Addr : constant Node_Id :=
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr (Larray, True),
Expressions => New_List (New_Copy_Tree (Left_Lo))),
Attribute_Name => Name_Address);
L_Bit : constant Node_Id :=
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr (Larray, True),
Expressions => New_List (New_Copy_Tree (Left_Lo))),
Attribute_Name => Name_Bit);
R_Addr : constant Node_Id :=
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr (Rarray, True),
Expressions => New_List (New_Copy_Tree (Right_Lo))),
Attribute_Name => Name_Address);
R_Bit : constant Node_Id :=
Make_Attribute_Reference (Loc,
Prefix =>
Make_Indexed_Component (Loc,
Prefix =>
Duplicate_Subexpr (Rarray, True),
Expressions => New_List (New_Copy_Tree (Right_Lo))),
Attribute_Name => Name_Bit);
-- Compute the Size of the bitfield
-- Note that the length check has already been done, so we can use the
-- size of either L or R; they are equal. We can't use 'Size here,
-- because sometimes bit fields get copied into a temp, and the 'Size
-- ends up being the size of the temp (e.g. an 8-bit temp containing
-- a 4-bit bit field).
Size : constant Node_Id :=
Make_Op_Multiply (Loc,
Make_Attribute_Reference (Loc,
Prefix =>
Duplicate_Subexpr (Name (N), True),
Attribute_Name => Name_Length),
Make_Attribute_Reference (Loc,
Prefix =>
Duplicate_Subexpr (Name (N), True),
Attribute_Name => Name_Component_Size));
begin
return Make_Procedure_Call_Statement (Loc,
Name => New_Occurrence_Of (RTE (RE_Copy_Bitfield), Loc),
Parameter_Associations => New_List (
R_Addr, R_Bit, L_Addr, L_Bit, Size));
end Expand_Assign_Array_Bitfield;
---------------------------------------
-- Expand_Assign_Array_Bitfield_Fast --
---------------------------------------
function Expand_Assign_Array_Bitfield_Fast
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id) return Node_Id
is
pragma Assert (not Change_Of_Representation (N));
-- This won't work, for example, to copy a packed array to an unpacked
-- array.
-- For L (A .. B) := R (C .. D), we generate:
--
-- L := Fast_Copy_Bitfield (R, <offset of R(C)>, L, <offset of L(A)>,
-- L (A .. B)'Length * L'Component_Size);
--
-- with L and R suitably uncheckedly converted to/from Val_2.
-- The offsets are from the start of L and R.
Loc : constant Source_Ptr := Sloc (N);
L_Typ : constant Entity_Id := Etype (Larray);
R_Typ : constant Entity_Id := Etype (Rarray);
-- The original type of the arrays
L_Val : constant Node_Id :=
Unchecked_Convert_To (RTE (RE_Val_2), Larray);
R_Val : constant Node_Id :=
Unchecked_Convert_To (RTE (RE_Val_2), Rarray);
-- Converted values of left- and right-hand sides
L_Small : constant Boolean :=
Known_Static_RM_Size (L_Typ)
and then RM_Size (L_Typ) < Standard_Long_Long_Integer_Size;
R_Small : constant Boolean :=
Known_Static_RM_Size (R_Typ)
and then RM_Size (R_Typ) < Standard_Long_Long_Integer_Size;
-- Whether the above unchecked conversions need to be padded with zeros
C_Size : constant Uint := Component_Size (L_Typ);
pragma Assert (C_Size >= 1);
pragma Assert (C_Size = Component_Size (R_Typ));
Larray_Bounds : constant Range_Values :=
Get_Index_Bounds (First_Index (L_Typ));
L_Bounds : constant Range_Values :=
(if Nkind (Name (N)) = N_Slice
then Get_Index_Bounds (Discrete_Range (Name (N)))
else Larray_Bounds);
-- If the left-hand side is A (First..Last), Larray_Bounds is A'Range,
-- and L_Bounds is First..Last. If it's not a slice, we treat it like
-- a slice starting at A'First.
L_Bit : constant Node_Id :=
Make_Integer_Literal
(Loc, (L_Bounds.First - Larray_Bounds.First) * C_Size);
Rarray_Bounds : constant Range_Values :=
Get_Index_Bounds (First_Index (R_Typ));
R_Bounds : constant Range_Values :=
(if Nkind (Expression (N)) = N_Slice
then Get_Index_Bounds (Discrete_Range (Expression (N)))
else Rarray_Bounds);
R_Bit : constant Node_Id :=
Make_Integer_Literal
(Loc, (R_Bounds.First - Rarray_Bounds.First) * C_Size);
Size : constant Node_Id :=
Make_Op_Multiply (Loc,
Make_Attribute_Reference (Loc,
Prefix =>
Duplicate_Subexpr (Name (N), True),
Attribute_Name => Name_Length),
Make_Attribute_Reference (Loc,
Prefix =>
Duplicate_Subexpr (Larray, True),
Attribute_Name => Name_Component_Size));
L_Arg, R_Arg, Call : Node_Id;
begin
-- The semantics of unchecked conversion between bit-packed arrays that
-- are implemented as modular types and modular types is precisely that
-- of unchecked conversion between modular types. Therefore, if it needs
-- to be padded with zeros, the padding must be moved to the correct end
-- for memory order because System.Bitfield_Utils works in memory order.
if L_Small
and then (Bytes_Big_Endian xor Reverse_Storage_Order (L_Typ))
then
L_Arg := Make_Op_Shift_Left (Loc,
Left_Opnd => L_Val,
Right_Opnd => Make_Integer_Literal (Loc,
Standard_Long_Long_Integer_Size - RM_Size (L_Typ)));
else
L_Arg := L_Val;
end if;
if R_Small
and then (Bytes_Big_Endian xor Reverse_Storage_Order (R_Typ))
then
R_Arg := Make_Op_Shift_Left (Loc,
Left_Opnd => R_Val,
Right_Opnd => Make_Integer_Literal (Loc,
Standard_Long_Long_Integer_Size - RM_Size (R_Typ)));
else
R_Arg := R_Val;
end if;
Call := Make_Function_Call (Loc,
Name => New_Occurrence_Of (RTE (RE_Fast_Copy_Bitfield), Loc),
Parameter_Associations => New_List (
R_Arg, R_Bit, L_Arg, L_Bit, Size));
-- Conversely, the final unchecked conversion must take significant bits
if L_Small
and then (Bytes_Big_Endian xor Reverse_Storage_Order (L_Typ))
then
Call := Make_Op_Shift_Right (Loc,
Left_Opnd => Call,
Right_Opnd => Make_Integer_Literal (Loc,
Standard_Long_Long_Integer_Size - RM_Size (L_Typ)));
end if;
return Make_Assignment_Statement (Loc,
Name => Duplicate_Subexpr (Larray, True),
Expression => Unchecked_Convert_To (L_Typ, Call));
end Expand_Assign_Array_Bitfield_Fast;
------------------------------------------
-- Expand_Assign_Array_Loop_Or_Bitfield --
------------------------------------------
function Expand_Assign_Array_Loop_Or_Bitfield
(N : Node_Id;
Larray : Entity_Id;
Rarray : Entity_Id;
L_Type : Entity_Id;
R_Type : Entity_Id;
Ndim : Pos;
Rev : Boolean) return Node_Id
is
function Volatile_Or_Independent
(Exp : Node_Id; Typ : Entity_Id) return Boolean;
-- Exp is an expression of type Typ, or if there is no expression
-- involved, Exp is Empty. True if there are any volatile or independent
-- objects that should disable the optimization. We check the object
-- itself, all subcomponents, and if Exp is a slice of a component or
-- slice, we check the prefix and its type.
--
-- We disable the optimization when there are relevant volatile or
-- independent objects, because Copy_Bitfield can read and write bits
-- that are not part of the objects being copied.
-----------------------------
-- Volatile_Or_Independent --
-----------------------------
function Volatile_Or_Independent
(Exp : Node_Id; Typ : Entity_Id) return Boolean
is
begin
-- Initially, Exp is the left- or right-hand side. In recursive
-- calls, Exp is Empty if we're just checking a component type, and
-- Exp is the prefix if we're checking the prefix of a slice.
if Present (Exp)
and then (Is_Volatile_Object_Ref (Exp)
or else Is_Independent_Object (Exp))
then
return True;
end if;
if Has_Volatile_Components (Typ)
or else Has_Independent_Components (Typ)
then
return True;
end if;
if Is_Array_Type (Typ) then
if Volatile_Or_Independent (Empty, Component_Type (Typ)) then
return True;
end if;
elsif Is_Record_Type (Typ) then
declare
Comp : Entity_Id := First_Component (Typ);
begin
while Present (Comp) loop
if Volatile_Or_Independent (Empty, Comp) then
return True;
end if;
Next_Component (Comp);
end loop;
end;
end if;
if Nkind (Exp) = N_Slice
and then Nkind (Prefix (Exp)) in
N_Selected_Component | N_Indexed_Component | N_Slice
then
if Volatile_Or_Independent (Prefix (Exp), Etype (Prefix (Exp)))
then
return True;
end if;
end if;
return False;
end Volatile_Or_Independent;
function Slice_Of_Packed_Component (L : Node_Id) return Boolean is
(Nkind (L) = N_Slice
and then Nkind (Prefix (L)) = N_Indexed_Component
and then Is_Bit_Packed_Array (Etype (Prefix (Prefix (L)))));
-- L is the left-hand side Name. Returns True if L is a slice of a
-- component of a bit-packed array. The optimization is disabled in
-- that case, because Expand_Assign_Array_Bitfield_Fast cannot
-- currently handle that case correctly.
L : constant Node_Id := Name (N);
R : constant Node_Id := Expression (N);
-- Left- and right-hand sides of the assignment statement
Slices : constant Boolean :=
Nkind (L) = N_Slice or else Nkind (R) = N_Slice;
-- Start of processing for Expand_Assign_Array_Loop_Or_Bitfield
begin
-- Determine whether Copy_Bitfield or Fast_Copy_Bitfield is appropriate
-- (will work, and will be more efficient than component-by-component
-- copy). Copy_Bitfield doesn't work for reversed storage orders. It is
-- efficient for slices of bit-packed arrays.
if Is_Bit_Packed_Array (L_Type)
and then Is_Bit_Packed_Array (R_Type)
and then not Reverse_Storage_Order (L_Type)
and then not Reverse_Storage_Order (R_Type)
and then Slices
and then not Slice_Of_Packed_Component (L)
and then not Volatile_Or_Independent (L, L_Type)
and then not Volatile_Or_Independent (R, R_Type)
then
-- Here if Copy_Bitfield can work (except for the Rev test below).
-- Determine whether to call Fast_Copy_Bitfield instead. If we
-- are assigning slices, and all the relevant bounds are known at
-- compile time, and the maximum object size is no greater than
-- System.Bitfields.Val_Bits (i.e. Long_Long_Integer'Size / 2), and
-- we don't have enumeration representation clauses, we can use
-- Fast_Copy_Bitfield. The max size test is to ensure that the slices
-- cannot overlap boundaries not supported by Fast_Copy_Bitfield.
pragma Assert (Known_Component_Size (Base_Type (L_Type)));
pragma Assert (Known_Component_Size (Base_Type (R_Type)));
-- Note that L_Type and R_Type do not necessarily have the same base
-- type, because of array type conversions. Hence the need to check
-- various properties of both.
if Compile_Time_Known_Bounds (Base_Type (L_Type))
and then Compile_Time_Known_Bounds (Base_Type (R_Type))
then
declare
Left_Base_Index : constant Entity_Id :=
First_Index (Base_Type (L_Type));
Left_Base_Range : constant Range_Values :=
Get_Index_Bounds (Left_Base_Index);
Right_Base_Index : constant Entity_Id :=
First_Index (Base_Type (R_Type));
Right_Base_Range : constant Range_Values :=
Get_Index_Bounds (Right_Base_Index);
Known_Left_Slice_Low : constant Boolean :=
(if Nkind (L) = N_Slice
then Compile_Time_Known_Value
(Get_Index_Bounds (Discrete_Range (L)).First));
Known_Right_Slice_Low : constant Boolean :=
(if Nkind (R) = N_Slice
then Compile_Time_Known_Value
(Get_Index_Bounds (Discrete_Range (R)).Last));
Val_Bits : constant Pos := Standard_Long_Long_Integer_Size / 2;
begin
if Left_Base_Range.Last - Left_Base_Range.First < Val_Bits
and then Right_Base_Range.Last - Right_Base_Range.First <
Val_Bits
and then Known_Esize (L_Type)
and then Known_Esize (R_Type)
and then Known_Left_Slice_Low
and then Known_Right_Slice_Low
and then Compile_Time_Known_Value
(Get_Index_Bounds (First_Index (Etype (Larray))).First)
and then Compile_Time_Known_Value
(Get_Index_Bounds (First_Index (Etype (Rarray))).First)
and then
not (Is_Enumeration_Type (Etype (Left_Base_Index))
and then Has_Enumeration_Rep_Clause
(Etype (Left_Base_Index)))
and then RTE_Available (RE_Fast_Copy_Bitfield)
then
pragma Assert (Known_Esize (L_Type));
pragma Assert (Known_Esize (R_Type));
return Expand_Assign_Array_Bitfield_Fast (N, Larray, Rarray);
end if;
end;
end if;
-- Fast_Copy_Bitfield can work if Rev is True, because the data is
-- passed and returned by copy. Copy_Bitfield cannot.
if not Rev and then RTE_Available (RE_Copy_Bitfield) then
return Expand_Assign_Array_Bitfield
(N, Larray, Rarray, L_Type, R_Type, Rev);
end if;
end if;
-- Here if we did not return above, with Fast_Copy_Bitfield or
-- Copy_Bitfield.
return Expand_Assign_Array_Loop
(N, Larray, Rarray, L_Type, R_Type, Ndim, Rev);
end Expand_Assign_Array_Loop_Or_Bitfield;
--------------------------
-- Expand_Assign_Record --
--------------------------
procedure Expand_Assign_Record (N : Node_Id) is
Lhs : constant Node_Id := Name (N);
Rhs : Node_Id := Expression (N);
L_Typ : constant Entity_Id := Base_Type (Etype (Lhs));
begin
-- If change of representation, then extract the real right-hand side
-- from the type conversion, and proceed with component-wise assignment,
-- since the two types are not the same as far as the back end is
-- concerned.
if Change_Of_Representation (N) then
Rhs := Expression (Rhs);
-- If this may be a case of a large bit aligned component, then proceed
-- with component-wise assignment, to avoid possible clobbering of other
-- components sharing bits in the first or last byte of the component to
-- be assigned.
elsif Possible_Bit_Aligned_Component (Lhs)
or else
Possible_Bit_Aligned_Component (Rhs)
then
null;
-- If we have a tagged type that has a complete record representation
-- clause, we must do we must do component-wise assignments, since child
-- types may have used gaps for their components, and we might be
-- dealing with a view conversion.
elsif Is_Fully_Repped_Tagged_Type (L_Typ) then
null;
-- If neither condition met, then nothing special to do, the back end
-- can handle assignment of the entire component as a single entity.
else
return;
end if;
-- At this stage we know that we must do a component wise assignment
declare
Loc : constant Source_Ptr := Sloc (N);
R_Typ : constant Entity_Id := Base_Type (Etype (Rhs));
Decl : constant Node_Id := Declaration_Node (R_Typ);
RDef : Node_Id;
F : Entity_Id;
function Find_Component
(Typ : Entity_Id;
Comp : Entity_Id) return Entity_Id;
-- Find the component with the given name in the underlying record
-- declaration for Typ. We need to use the actual entity because the
-- type may be private and resolution by identifier alone would fail.
function Make_Component_List_Assign
(CL : Node_Id;
U_U : Boolean := False) return List_Id;
-- Returns a sequence of statements to assign the components that
-- are referenced in the given component list. The flag U_U is
-- used to force the usage of the inferred value of the variant
-- part expression as the switch for the generated case statement.
function Make_Field_Assign
(C : Entity_Id;
U_U : Boolean := False) return Node_Id;
-- Given C, the entity for a discriminant or component, build an
-- assignment for the corresponding field values. The flag U_U
-- signals the presence of an Unchecked_Union and forces the usage
-- of the inferred discriminant value of C as the right-hand side
-- of the assignment.
function Make_Field_Assigns (CI : List_Id) return List_Id;
-- Given CI, a component items list, construct series of statements
-- for fieldwise assignment of the corresponding components.
--------------------
-- Find_Component --
--------------------
function Find_Component
(Typ : Entity_Id;
Comp : Entity_Id) return Entity_Id
is
Utyp : constant Entity_Id := Underlying_Type (Typ);
C : Entity_Id;
begin
C := First_Entity (Utyp);
while Present (C) loop
if Chars (C) = Chars (Comp) then
return C;
-- The component may be a renamed discriminant, in
-- which case check against the name of the original
-- discriminant of the parent type.
elsif Is_Derived_Type (Scope (Comp))
and then Ekind (Comp) = E_Discriminant
and then Present (Corresponding_Discriminant (Comp))
and then
Chars (C) = Chars (Corresponding_Discriminant (Comp))
then
return C;
end if;
Next_Entity (C);
end loop;
raise Program_Error;
end Find_Component;
--------------------------------
-- Make_Component_List_Assign --
--------------------------------
function Make_Component_List_Assign
(CL : Node_Id;
U_U : Boolean := False) return List_Id
is
CI : constant List_Id := Component_Items (CL);
VP : constant Node_Id := Variant_Part (CL);
Alts : List_Id;
DC : Node_Id;
DCH : List_Id;
Expr : Node_Id;
Result : List_Id;
V : Node_Id;
begin
Result := Make_Field_Assigns (CI);
if Present (VP) then
V := First_Non_Pragma (Variants (VP));
Alts := New_List;
while Present (V) loop
DCH := New_List;
DC := First (Discrete_Choices (V));
while Present (DC) loop
Append_To (DCH, New_Copy_Tree (DC));
Next (DC);
end loop;
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Discrete_Choices => DCH,
Statements =>
Make_Component_List_Assign (Component_List (V))));
Next_Non_Pragma (V);
end loop;
-- Try to find a constrained type or a derived type to extract
-- discriminant values from, so that the case statement built
-- below can be folded by Expand_N_Case_Statement.
if U_U or else Is_Constrained (Etype (Rhs)) then
Expr :=
New_Copy (Get_Discriminant_Value (
Entity (Name (VP)),
Etype (Rhs),
Discriminant_Constraint (Etype (Rhs))));
elsif Is_Constrained (Etype (Expression (N))) then
Expr :=
New_Copy (Get_Discriminant_Value (
Entity (Name (VP)),
Etype (Expression (N)),
Discriminant_Constraint (Etype (Expression (N)))));
elsif Is_Derived_Type (Etype (Rhs))
and then Present (Stored_Constraint (Etype (Rhs)))
then
Expr :=
New_Copy (Get_Discriminant_Value (
Corresponding_Record_Component (Entity (Name (VP))),
Etype (Etype (Rhs)),
Stored_Constraint (Etype (Rhs))));
else
Expr := Empty;
end if;
if No (Expr) or else not Compile_Time_Known_Value (Expr) then
Expr :=
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Selector_Name =>
Make_Identifier (Loc, Chars (Name (VP))));
end if;
Append_To (Result,
Make_Case_Statement (Loc,
Expression => Expr,
Alternatives => Alts));
end if;
return Result;
end Make_Component_List_Assign;
-----------------------
-- Make_Field_Assign --
-----------------------
function Make_Field_Assign
(C : Entity_Id;
U_U : Boolean := False) return Node_Id
is
A : Node_Id;
Disc : Entity_Id;
Expr : Node_Id;
begin
-- The discriminant entity to be used in the retrieval below must
-- be one in the corresponding type, given that the assignment may
-- be between derived and parent types.
if Is_Derived_Type (Etype (Rhs)) then
Disc := Find_Component (R_Typ, C);
else
Disc := C;
end if;
-- In the case of an Unchecked_Union, use the discriminant
-- constraint value as on the right-hand side of the assignment.
if U_U then
Expr :=
New_Copy (Get_Discriminant_Value (C,
Etype (Rhs),
Discriminant_Constraint (Etype (Rhs))));
else
Expr :=
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Selector_Name => New_Occurrence_Of (Disc, Loc));
end if;
-- Generate the assignment statement. When the left-hand side
-- is an object with an address clause present, force generated
-- temporaries to be renamings so as to correctly assign to any
-- overlaid objects.
A :=
Make_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix =>
Duplicate_Subexpr
(Exp => Lhs,
Name_Req => False,
Renaming_Req =>
Is_Entity_Name (Lhs)
and then Present (Address_Clause (Entity (Lhs)))),
Selector_Name =>
New_Occurrence_Of (Find_Component (L_Typ, C), Loc)),
Expression => Expr);
-- Set Assignment_OK, so discriminants can be assigned
Set_Assignment_OK (Name (A), True);
if Componentwise_Assignment (N)
and then Nkind (Name (A)) = N_Selected_Component
and then Chars (Selector_Name (Name (A))) = Name_uParent
then
Set_Componentwise_Assignment (A);
end if;
return A;
end Make_Field_Assign;
------------------------
-- Make_Field_Assigns --
------------------------
function Make_Field_Assigns (CI : List_Id) return List_Id is
Item : Node_Id;
Result : List_Id;
begin
Item := First (CI);
Result := New_List;
while Present (Item) loop
-- Look for components, but exclude _tag field assignment if
-- the special Componentwise_Assignment flag is set.
if Nkind (Item) = N_Component_Declaration
and then not (Is_Tag (Defining_Identifier (Item))
and then Componentwise_Assignment (N))
then
Append_To
(Result, Make_Field_Assign (Defining_Identifier (Item)));
end if;
Next (Item);
end loop;
return Result;
end Make_Field_Assigns;
-- Start of processing for Expand_Assign_Record
begin
-- Note that we need to use the base types for this processing in
-- order to retrieve the Type_Definition. In the constrained case,
-- we filter out the non relevant fields in
-- Make_Component_List_Assign.
-- First copy the discriminants. This is done unconditionally. It
-- is required in the unconstrained left side case, and also in the
-- case where this assignment was constructed during the expansion
-- of a type conversion (since initialization of discriminants is
-- suppressed in this case). It is unnecessary but harmless in
-- other cases.
-- Special case: no copy if the target has no discriminants
if Has_Discriminants (L_Typ)
and then Is_Unchecked_Union (Base_Type (L_Typ))
then
null;
elsif Has_Discriminants (L_Typ) then
F := First_Discriminant (R_Typ);
while Present (F) loop
-- If we are expanding the initialization of a derived record
-- that constrains or renames discriminants of the parent, we
-- must use the corresponding discriminant in the parent.
declare
CF : Entity_Id;
begin
if Inside_Init_Proc
and then Present (Corresponding_Discriminant (F))
then
CF := Corresponding_Discriminant (F);
else
CF := F;
end if;
if Is_Unchecked_Union (R_Typ) then
-- Within an initialization procedure this is the
-- assignment to an unchecked union component, in which
-- case there is no discriminant to initialize.
if Inside_Init_Proc then
null;
else
-- The assignment is part of a conversion from a
-- derived unchecked union type with an inferable
-- discriminant, to a parent type.
Insert_Action (N, Make_Field_Assign (CF, True));
end if;
else
Insert_Action (N, Make_Field_Assign (CF));
end if;
Next_Discriminant (F);
end;
end loop;
-- If the derived type has a stored constraint, assign the value
-- of the corresponding discriminants explicitly, skipping those
-- that are renamed discriminants. We cannot just retrieve them
-- from the Rhs by selected component because they are invisible
-- in the type of the right-hand side.
if Present (Stored_Constraint (R_Typ)) then
declare
Assign : Node_Id;
Discr_Val : Elmt_Id;
begin
Discr_Val := First_Elmt (Stored_Constraint (R_Typ));
F := First_Entity (R_Typ);
while Present (F) loop
if Ekind (F) = E_Discriminant
and then Is_Completely_Hidden (F)
and then Present (Corresponding_Record_Component (F))
and then
(not Is_Entity_Name (Node (Discr_Val))
or else Ekind (Entity (Node (Discr_Val))) /=
E_Discriminant)
then
Assign :=
Make_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Lhs),
Selector_Name =>
New_Occurrence_Of
(Corresponding_Record_Component (F), Loc)),
Expression => New_Copy (Node (Discr_Val)));
Set_Assignment_OK (Name (Assign));
Insert_Action (N, Assign);
Next_Elmt (Discr_Val);
end if;
Next_Entity (F);
end loop;
end;
end if;
end if;
-- We know the underlying type is a record, but its current view
-- may be private. We must retrieve the usable record declaration.
if Nkind (Decl) in N_Private_Type_Declaration
| N_Private_Extension_Declaration
and then Present (Full_View (R_Typ))
then
RDef := Type_Definition (Declaration_Node (Full_View (R_Typ)));
else
RDef := Type_Definition (Decl);
end if;
if Nkind (RDef) = N_Derived_Type_Definition then
RDef := Record_Extension_Part (RDef);
end if;
if Nkind (RDef) = N_Record_Definition
and then Present (Component_List (RDef))
then
if Is_Unchecked_Union (R_Typ) then
Insert_Actions (N,
Make_Component_List_Assign (Component_List (RDef), True));
else
Insert_Actions (N,
Make_Component_List_Assign (Component_List (RDef)));
end if;
Rewrite (N, Make_Null_Statement (Loc));
end if;
end;
end Expand_Assign_Record;
-------------------------------------
-- Expand_Assign_With_Target_Names --
-------------------------------------
procedure Expand_Assign_With_Target_Names (N : Node_Id) is
LHS : constant Node_Id := Name (N);
LHS_Typ : constant Entity_Id := Etype (LHS);
Loc : constant Source_Ptr := Sloc (N);
RHS : constant Node_Id := Expression (N);
Ent : Entity_Id;
-- The entity of the left-hand side
function Replace_Target (N : Node_Id) return Traverse_Result;
-- Replace occurrences of the target name by the proper entity: either
-- the entity of the LHS in simple cases, or the formal of the
-- constructed procedure otherwise.
--------------------
-- Replace_Target --
--------------------
function Replace_Target (N : Node_Id) return Traverse_Result is
begin
if Nkind (N) = N_Target_Name then
Rewrite (N, New_Occurrence_Of (Ent, Sloc (N)));
-- The expression will be reanalyzed when the enclosing assignment
-- is reanalyzed, so reset the entity, which may be a temporary
-- created during analysis, e.g. a loop variable for an iterated
-- component association. However, if entity is callable then
-- resolution has established its proper identity (including in
-- rewritten prefixed calls) so we must preserve it.
elsif Is_Entity_Name (N) then
if Present (Entity (N))
and then not Is_Overloadable (Entity (N))
then
Set_Entity (N, Empty);
end if;
end if;
Set_Analyzed (N, False);
return OK;
end Replace_Target;
procedure Replace_Target_Name is new Traverse_Proc (Replace_Target);
-- Local variables
New_RHS : Node_Id;
Proc_Id : Entity_Id;
-- Start of processing for Expand_Assign_With_Target_Names
begin
New_RHS := New_Copy_Tree (RHS);
-- The left-hand side is a direct name
if Is_Entity_Name (LHS)
and then not Is_Renaming_Of_Object (Entity (LHS))
then
Ent := Entity (LHS);
Replace_Target_Name (New_RHS);
-- Generate:
-- LHS := ... LHS ...;
Rewrite (N,
Make_Assignment_Statement (Loc,
Name => Relocate_Node (LHS),
Expression => New_RHS));
-- The left-hand side is not a direct name, but is side-effect-free.
-- Capture its value in a temporary to avoid generating a procedure.
-- We don't do this optimization if the target object's type may need
-- finalization actions, because we don't want extra finalizations to
-- be done for the temp object, and instead we use the more general
-- procedure-based approach below.
elsif Side_Effect_Free (LHS)
and then not Needs_Finalization (Etype (LHS))
then
Ent := Make_Temporary (Loc, 'T');
Replace_Target_Name (New_RHS);
-- Generate:
-- T : LHS_Typ := LHS;
Insert_Before_And_Analyze (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Ent,
Object_Definition => New_Occurrence_Of (LHS_Typ, Loc),
Expression => New_Copy_Tree (LHS)));
-- Generate:
-- LHS := ... T ...;
Rewrite (N,
Make_Assignment_Statement (Loc,
Name => Relocate_Node (LHS),
Expression => New_RHS));
-- Otherwise wrap the whole assignment statement in a procedure with an
-- IN OUT parameter. The original assignment then becomes a call to the
-- procedure with the left-hand side as an actual.
else
Ent := Make_Temporary (Loc, 'T');
Replace_Target_Name (New_RHS);
-- Generate:
-- procedure P (T : in out LHS_Typ) is
-- begin
-- T := ... T ...;
-- end P;
Proc_Id := Make_Temporary (Loc, 'P');
Insert_Before_And_Analyze (N,
Make_Subprogram_Body (Loc,
Specification =>
Make_Procedure_Specification (Loc,
Defining_Unit_Name => Proc_Id,
Parameter_Specifications => New_List (
Make_Parameter_Specification (Loc,
Defining_Identifier => Ent,
In_Present => True,
Out_Present => True,
Parameter_Type =>
New_Occurrence_Of (LHS_Typ, Loc)))),
Declarations => Empty_List,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Ent, Loc),
Expression => New_RHS)))));
-- Generate:
-- P (LHS);
Rewrite (N,
Make_Procedure_Call_Statement (Loc,
Name => New_Occurrence_Of (Proc_Id, Loc),
Parameter_Associations => New_List (Relocate_Node (LHS))));
end if;
-- Analyze rewritten node, either as assignment or procedure call
Analyze (N);
end Expand_Assign_With_Target_Names;
-----------------------------------
-- Expand_N_Assignment_Statement --
-----------------------------------
-- This procedure implements various cases where an assignment statement
-- cannot just be passed on to the back end in untransformed state.
procedure Expand_N_Assignment_Statement (N : Node_Id) is
Crep : constant Boolean := Change_Of_Representation (N);
Lhs : constant Node_Id := Name (N);
Loc : constant Source_Ptr := Sloc (N);
Rhs : constant Node_Id := Expression (N);
-- Obtain the relevant corresponding mutably tagged type if necessary
Typ : constant Entity_Id :=
Get_Corresponding_Mutably_Tagged_Type_If_Present
(Underlying_Type (Etype (Lhs)));
Exp : Node_Id;
begin
-- Special case to check right away, if the Componentwise_Assignment
-- flag is set, this is a reanalysis from the expansion of the primitive
-- assignment procedure for a tagged type, and all we need to do is to
-- expand to assignment of components, because otherwise, we would get
-- infinite recursion (since this looks like a tagged assignment which
-- would normally try to *call* the primitive assignment procedure).
if Componentwise_Assignment (N) then
Expand_Assign_Record (N);
return;
end if;
-- Defend against invalid subscripts on left side if we are in standard
-- validity checking mode. No need to do this if we are checking all
-- subscripts.
-- Note that we do this right away, because there are some early return
-- paths in this procedure, and this is required on all paths.
if Validity_Checks_On
and then Validity_Check_Default
and then not Validity_Check_Subscripts
then
Check_Valid_Lvalue_Subscripts (Lhs);
end if;
-- Separate expansion if RHS contain target names. Note that assignment
-- may already have been expanded if RHS is aggregate.
if Nkind (N) = N_Assignment_Statement and then Has_Target_Names (N) then
Expand_Assign_With_Target_Names (N);
return;
end if;
-- Ada 2005 (AI-327): Handle assignment to priority of protected object
-- Rewrite an assignment to X'Priority into a run-time call
-- For example: X'Priority := New_Prio_Expr;
-- ...is expanded into Set_Ceiling (X._Object, New_Prio_Expr);
-- Note that although X'Priority is notionally an object, it is quite
-- deliberately not defined as an aliased object in the RM. This means
-- that it works fine to rewrite it as a call, without having to worry
-- about complications that would other arise from X'Priority'Access,
-- which is illegal, because of the lack of aliasing.
if Ada_Version >= Ada_2005 then
declare
Call : Node_Id;
Ent : Entity_Id;
Prottyp : Entity_Id;
RT_Subprg : RE_Id;
begin
-- Handle chains of renamings
Ent := Name (N);
while Nkind (Ent) in N_Has_Entity
and then Present (Entity (Ent))
and then Is_Object (Entity (Ent))
and then Present (Renamed_Object (Entity (Ent)))
loop
Ent := Renamed_Object (Entity (Ent));
end loop;
-- The attribute Priority applied to protected objects has been
-- previously expanded into a call to the Get_Ceiling run-time
-- subprogram. In restricted profiles this is not available.
if Is_Expanded_Priority_Attribute (Ent) then
-- Look for the enclosing protected type
Prottyp := Current_Scope;
while not Is_Protected_Type (Prottyp) loop
Prottyp := Scope (Prottyp);
end loop;
pragma Assert (Is_Protected_Type (Prottyp));
-- Select the appropriate run-time call
if Has_Entries (Prottyp) then
RT_Subprg := RO_PE_Set_Ceiling;
else
RT_Subprg := RE_Set_Ceiling;
end if;
Call :=
Make_Procedure_Call_Statement (Loc,
Name =>
New_Occurrence_Of (RTE (RT_Subprg), Loc),
Parameter_Associations => New_List (
New_Copy_Tree (First (Parameter_Associations (Ent))),
Relocate_Node (Expression (N))));
Rewrite (N, Call);
Analyze (N);
return;
end if;
end;
end if;
-- Deal with assignment checks unless suppressed
if not Suppress_Assignment_Checks (N) then
-- First deal with generation of range check if required,
-- and then predicate checks if the type carries a predicate.
-- If the Rhs is an expression these tests may have been applied
-- already. This is the case if the RHS is a type conversion.
-- Other such redundant checks could be removed ???
if Nkind (Rhs) /= N_Type_Conversion
or else Entity (Subtype_Mark (Rhs)) /= Typ
then
if Do_Range_Check (Rhs) then
Generate_Range_Check (Rhs, Typ, CE_Range_Check_Failed);
end if;
Apply_Predicate_Check (Rhs, Typ);
end if;
end if;
-- Check for a special case where a high level transformation is
-- required. If we have either of:
-- P.field := rhs;
-- P (sub) := rhs;
-- where P is a reference to a bit packed array, then we have to unwind
-- the assignment. The exact meaning of being a reference to a bit
-- packed array is as follows:
-- An indexed component whose prefix is a bit packed array is a
-- reference to a bit packed array.
-- An indexed component or selected component whose prefix is a
-- reference to a bit packed array is itself a reference ot a
-- bit packed array.
-- The required transformation is
-- Tnn : prefix_type := P;
-- Tnn.field := rhs;
-- P := Tnn;
-- or
-- Tnn : prefix_type := P;
-- Tnn (subscr) := rhs;
-- P := Tnn;
-- Since P is going to be evaluated more than once, any subscripts
-- in P must have their evaluation forced.
if Nkind (Lhs) in N_Indexed_Component | N_Selected_Component
and then Is_Ref_To_Bit_Packed_Array (Prefix (Lhs))
then
declare
BPAR_Expr : constant Node_Id := Relocate_Node (Prefix (Lhs));
BPAR_Typ : constant Entity_Id := Etype (BPAR_Expr);
Tnn : constant Entity_Id :=
Make_Temporary (Loc, 'T', BPAR_Expr);
begin
-- Insert the post assignment first, because we want to copy the
-- BPAR_Expr tree before it gets analyzed in the context of the
-- pre assignment. Note that we do not analyze the post assignment
-- yet (we cannot till we have completed the analysis of the pre
-- assignment). As usual, the analysis of this post assignment
-- will happen on its own when we "run into" it after finishing
-- the current assignment.
Insert_After (N,
Make_Assignment_Statement (Loc,
Name => New_Copy_Tree (BPAR_Expr),
Expression => New_Occurrence_Of (Tnn, Loc)));
-- At this stage BPAR_Expr is a reference to a bit packed array
-- where the reference was not expanded in the original tree,
-- since it was on the left side of an assignment. But in the
-- pre-assignment statement (the object definition), BPAR_Expr
-- will end up on the right-hand side, and must be reexpanded. To
-- achieve this, we reset the analyzed flag of all selected and
-- indexed components down to the actual indexed component for
-- the packed array.
Exp := BPAR_Expr;
loop
Set_Analyzed (Exp, False);
if Nkind (Exp) in N_Indexed_Component | N_Selected_Component
then
Exp := Prefix (Exp);
else
exit;
end if;
end loop;
-- Now we can insert and analyze the pre-assignment
-- If the right-hand side requires a transient scope, it has
-- already been placed on the stack. However, the declaration is
-- inserted in the tree outside of this scope, and must reflect
-- the proper scope for its variable. This awkward bit is forced
-- by the stricter scope discipline imposed by GCC 2.97.
declare
Uses_Transient_Scope : constant Boolean :=
Scope_Is_Transient
and then N = Node_To_Be_Wrapped;
begin
if Uses_Transient_Scope then
Push_Scope (Scope (Current_Scope));
end if;
Insert_Before_And_Analyze (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Tnn,
Object_Definition => New_Occurrence_Of (BPAR_Typ, Loc),
Expression => BPAR_Expr));
if Uses_Transient_Scope then
Pop_Scope;
end if;
end;
-- Now fix up the original assignment and continue processing
Rewrite (Prefix (Lhs),
New_Occurrence_Of (Tnn, Loc));
-- We do not need to reanalyze that assignment, and we do not need
-- to worry about references to the temporary, but we do need to
-- make sure that the temporary is not marked as a true constant
-- since we now have a generated assignment to it.
Set_Is_True_Constant (Tnn, False);
end;
end if;
-- When we have the appropriate type of aggregate in the expression (it
-- has been determined during analysis of the aggregate by setting the
-- delay flag), let's perform in place assignment and thus avoid
-- creating a temporary.
if Is_Delayed_Aggregate (Rhs) then
Convert_Aggr_In_Assignment (N);
Rewrite (N, Make_Null_Statement (Loc));
Analyze (N);
return;
end if;
-- An assignment between nonnative storage models requires creating an
-- intermediate temporary on the host, which can potentially be large.
if Nkind (Lhs) = N_Explicit_Dereference
and then Has_Designated_Storage_Model_Aspect (Etype (Prefix (Lhs)))
and then Present (Storage_Model_Copy_To
(Storage_Model_Object (Etype (Prefix (Lhs)))))
and then Nkind (Rhs) = N_Explicit_Dereference
and then Has_Designated_Storage_Model_Aspect (Etype (Prefix (Rhs)))
and then Present (Storage_Model_Copy_From
(Storage_Model_Object (Etype (Prefix (Rhs)))))
then
declare
Assign_Code : List_Id;
Tmp : Entity_Id;
begin
Assign_Code := New_List;
Tmp := Build_Temporary_On_Secondary_Stack (Loc, Typ, Assign_Code);
Append_To (Assign_Code,
Make_Assignment_Statement (Loc,
Name =>
Make_Explicit_Dereference (Loc,
Prefix => New_Occurrence_Of (Tmp, Loc)),
Expression => Relocate_Node (Rhs)));
Append_To (Assign_Code,
Make_Assignment_Statement (Loc,
Name => Relocate_Node (Lhs),
Expression =>
Make_Explicit_Dereference (Loc,
Prefix => New_Occurrence_Of (Tmp, Loc))));
Insert_Actions (N, Assign_Code);
Rewrite (N, Make_Null_Statement (Loc));
return;
end;
end if;
-- Apply discriminant check if required. If Lhs is an access type to a
-- designated type with discriminants, we must always check. If the
-- type has unknown discriminants, more elaborate processing below.
if Has_Discriminants (Etype (Lhs))
and then not Has_Unknown_Discriminants (Etype (Lhs))
then
-- Skip discriminant check if change of representation. Will be
-- done when the change of representation is expanded out.
if not Crep and then not Suppress_Assignment_Checks (N) then
Apply_Discriminant_Check (Rhs, Etype (Lhs), Lhs);
end if;
-- If the type is private without discriminants, and the full type
-- has discriminants (necessarily with defaults) a check may still be
-- necessary if the Lhs is aliased. The private discriminants must be
-- visible to build the discriminant constraints.
-- Only an explicit dereference that comes from source indicates
-- aliasing. Access to formals of protected operations and entries
-- create dereferences but are not semantic aliasings.
elsif Is_Private_Type (Etype (Lhs))
and then Has_Discriminants (Typ)
and then Nkind (Lhs) = N_Explicit_Dereference
and then Comes_From_Source (Lhs)
then
declare
Lt : constant Entity_Id := Etype (Lhs);
Ubt : Entity_Id := Base_Type (Typ);
begin
-- In the case of an expander-generated record subtype whose base
-- type still appears private, Typ will have been set to that
-- private type rather than the underlying record type (because
-- Underlying type will have returned the record subtype), so it's
-- necessary to apply Underlying_Type again to the base type to
-- get the record type we need for the discriminant check. Such
-- subtypes can be created for assignments in certain cases, such
-- as within an instantiation passed this kind of private type.
-- It would be good to avoid this special test, but making changes
-- to prevent this odd form of record subtype seems difficult. ???
if Is_Private_Type (Ubt) then
Ubt := Underlying_Type (Ubt);
end if;
Set_Etype (Lhs, Ubt);
Rewrite (Rhs, OK_Convert_To (Base_Type (Ubt), Rhs));
if not Suppress_Assignment_Checks (N) then
Apply_Discriminant_Check (Rhs, Ubt, Lhs);
end if;
Set_Etype (Lhs, Lt);
end;
-- If the Lhs has a private type with unknown discriminants, it may
-- have a full view with discriminants, but those are nameable only
-- in the underlying type, so convert the Rhs to it before potential
-- checking. Convert Lhs as well, otherwise the actual subtype might
-- not be constructible. If the discriminants have defaults the type
-- is unconstrained and there is nothing to check.
-- Ditto if a private type with unknown discriminants has a full view
-- that is an unconstrained array, in which case a length check is
-- needed.
elsif Has_Unknown_Discriminants (Base_Type (Etype (Lhs))) then
if Has_Discriminants (Typ)
and then not Has_Defaulted_Discriminants (Typ)
then
Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs));
Rewrite (Lhs, OK_Convert_To (Base_Type (Typ), Lhs));
if not Suppress_Assignment_Checks (N) then
Apply_Discriminant_Check (Rhs, Typ, Lhs);
end if;
elsif Is_Array_Type (Typ) and then
(Is_Constrained (Typ) or else Is_Mutably_Tagged_Conversion (Lhs))
then
Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs));
Rewrite (Lhs, OK_Convert_To (Base_Type (Typ), Lhs));
if not Suppress_Assignment_Checks (N) then
Apply_Length_Check (Rhs, Typ);
end if;
end if;
-- In the access type case, we need the same discriminant check, and
-- also range checks if we have an access to constrained array.
elsif Is_Access_Type (Etype (Lhs))
and then Is_Constrained (Designated_Type (Etype (Lhs)))
and then not Suppress_Assignment_Checks (N)
then
if Has_Discriminants (Designated_Type (Etype (Lhs))) then
-- Skip discriminant check if change of representation. Will be
-- done when the change of representation is expanded out.
if not Crep then
Apply_Discriminant_Check (Rhs, Etype (Lhs));
end if;
elsif Is_Array_Type (Designated_Type (Etype (Lhs))) then
Apply_Range_Check (Rhs, Etype (Lhs));
if Is_Constrained (Etype (Lhs)) then
Apply_Length_Check (Rhs, Etype (Lhs));
end if;
end if;
end if;
-- Ada 2005 (AI-231): Generate the run-time check
if Is_Access_Type (Typ)
and then Can_Never_Be_Null (Etype (Lhs))
and then not Can_Never_Be_Null (Etype (Rhs))
-- If an actual is an out parameter of a null-excluding access
-- type, there is access check on entry, so we set the flag
-- Suppress_Assignment_Checks on the generated statement to
-- assign the actual to the parameter block, and we do not want
-- to generate an additional check at this point.
and then not Suppress_Assignment_Checks (N)
then
Apply_Constraint_Check (Rhs, Etype (Lhs));
end if;
-- Ada 2012 (AI05-148): Update current accessibility level if Rhs is a
-- stand-alone obj of an anonymous access type. Do not install the check
-- when the Lhs denotes a container cursor and the Next function employs
-- an access type, because this can never result in a dangling pointer.
if Is_Access_Type (Typ)
and then Is_Entity_Name (Lhs)
and then Ekind (Entity (Lhs)) /= E_Loop_Parameter
and then Present (Effective_Extra_Accessibility (Entity (Lhs)))
then
declare
function Lhs_Entity return Entity_Id;
-- Look through renames to find the underlying entity.
-- For assignment to a rename, we don't care about the
-- Enclosing_Dynamic_Scope of the rename declaration.
----------------
-- Lhs_Entity --
----------------
function Lhs_Entity return Entity_Id is
Result : Entity_Id := Entity (Lhs);
begin
while Present (Renamed_Object (Result)) loop
-- Renamed_Object must return an Entity_Name here
-- because of preceding "Present (E_E_A (...))" test.
Result := Entity (Renamed_Object (Result));
end loop;
return Result;
end Lhs_Entity;
-- Local Declarations
Access_Check : constant Node_Id :=
Make_Raise_Program_Error (Loc,
Condition =>
Make_Op_Gt (Loc,
Left_Opnd =>
Accessibility_Level (Rhs, Dynamic_Level),
Right_Opnd =>
Make_Integer_Literal (Loc,
Intval =>
Scope_Depth
(Enclosing_Dynamic_Scope
(Lhs_Entity)))),
Reason => PE_Accessibility_Check_Failed);
Access_Level_Update : constant Node_Id :=
Make_Assignment_Statement (Loc,
Name =>
New_Occurrence_Of
(Effective_Extra_Accessibility
(Entity (Lhs)), Loc),
Expression =>
Accessibility_Level
(Expr => Rhs,
Level => Dynamic_Level,
Allow_Alt_Model => False));
begin
if not Accessibility_Checks_Suppressed (Entity (Lhs)) then
Insert_Action (N, Access_Check);
end if;
Insert_Action (N, Access_Level_Update);
end;
end if;
-- Case of assignment to a bit packed array element. If there is a
-- change of representation this must be expanded into components,
-- otherwise this is a bit-field assignment.
if Nkind (Lhs) = N_Indexed_Component
and then Is_Bit_Packed_Array (Etype (Prefix (Lhs)))
then
-- Normal case, no change of representation
if not Crep then
Expand_Bit_Packed_Element_Set (N);
return;
-- Change of representation case
else
-- Generate the following, to force component-by-component
-- assignments in an efficient way. Otherwise each component
-- will require a temporary and two bit-field manipulations.
-- T1 : Elmt_Type;
-- T1 := RhS;
-- Lhs := T1;
declare
Tnn : constant Entity_Id := Make_Temporary (Loc, 'T');
Stats : List_Id;
begin
Stats :=
New_List (
Make_Object_Declaration (Loc,
Defining_Identifier => Tnn,
Object_Definition =>
New_Occurrence_Of (Etype (Lhs), Loc)),
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Tnn, Loc),
Expression => Relocate_Node (Rhs)),
Make_Assignment_Statement (Loc,
Name => Relocate_Node (Lhs),
Expression => New_Occurrence_Of (Tnn, Loc)));
Insert_Actions (N, Stats);
Rewrite (N, Make_Null_Statement (Loc));
Analyze (N);
end;
end if;
-- Build-in-place function call case. This is for assignment statements
-- that come from aggregate component associations or from init procs.
-- User-written assignment statements with b-i-p calls are handled
-- elsewhere.
elsif Is_Build_In_Place_Function_Call (Rhs) then
pragma Assert (not Comes_From_Source (N));
Make_Build_In_Place_Call_In_Assignment (N, Rhs);
elsif Is_Tagged_Type (Typ)
or else (Needs_Finalization (Typ) and then not Is_Array_Type (Typ))
then
Tagged_Case : declare
L : List_Id := No_List;
Expand_Ctrl_Actions : constant Boolean
:= not No_Ctrl_Actions (N)
and then not No_Finalize_Actions (N);
begin
-- In the controlled case, we ensure that function calls are
-- evaluated before finalizing the target. In all cases, it makes
-- the expansion easier if the side effects are removed first.
Remove_Side_Effects (Lhs);
Remove_Side_Effects (Rhs);
-- Avoid recursion in the mechanism
Set_Analyzed (N);
-- If dispatching assignment, we need to dispatch to _assign
if Is_Class_Wide_Type (Typ)
-- If the type is tagged, we may as well use the predefined
-- primitive assignment. This avoids inlining a lot of code
-- and in the class-wide case, the assignment is replaced
-- by a dispatching call to _assign. It is suppressed in the
-- case of assignments created by the expander that correspond
-- to initializations, where we do want to copy the tag
-- (Expand_Ctrl_Actions flag is set False in this case). It is
-- also suppressed if restriction No_Dispatching_Calls is in
-- force because in that case predefined primitives are not
-- generated.
or else (Is_Tagged_Type (Typ)
and then Chars (Current_Scope) /= Name_uAssign
and then Expand_Ctrl_Actions
and then
not Restriction_Active (No_Dispatching_Calls))
then
-- We should normally not encounter any limited type here,
-- except in the corner case where an assignment was not
-- intended like the pathological case of a raise expression
-- within a return statement.
if Is_Limited_Type (Typ) then
pragma Assert (not Comes_From_Source (N));
return;
end if;
-- Fetch the primitive op _assign and proper type to call it.
-- Because of possible conflicts between private and full view,
-- fetch the proper type directly from the operation profile.
declare
Op : constant Entity_Id :=
Find_Prim_Op (Typ, Name_uAssign);
F_Typ : Entity_Id := Etype (First_Formal (Op));
begin
-- If the assignment is dispatching, make sure to use the
-- proper type.
if Is_Class_Wide_Type (Typ) then
F_Typ := Class_Wide_Type (F_Typ);
end if;
L := New_List;
-- In case of assignment to a class-wide tagged type, before
-- the assignment we generate run-time check to ensure that
-- the tags of source and target match.
if not Tag_Checks_Suppressed (Typ)
and then Is_Class_Wide_Type (Typ)
and then Is_Tagged_Type (Typ)
and then Is_Tagged_Type (Underlying_Type (Etype (Rhs)))
then
declare
Lhs_Tag : Node_Id;
Rhs_Tag : Node_Id;
begin
if not Is_Interface (Typ) then
Lhs_Tag :=
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Lhs),
Selector_Name =>
Make_Identifier (Loc, Name_uTag));
Rhs_Tag :=
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Selector_Name =>
Make_Identifier (Loc, Name_uTag));
else
-- Displace the pointer to the base of the objects
-- applying 'Address, which is later expanded into
-- a call to RE_Base_Address.
Lhs_Tag :=
Make_Explicit_Dereference (Loc,
Prefix =>
Unchecked_Convert_To (RTE (RE_Tag_Ptr),
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (Lhs),
Attribute_Name => Name_Address)));
Rhs_Tag :=
Make_Explicit_Dereference (Loc,
Prefix =>
Unchecked_Convert_To (RTE (RE_Tag_Ptr),
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Attribute_Name => Name_Address)));
end if;
-- Handle assignment to a mutably tagged type
if Is_Mutably_Tagged_Conversion (Lhs)
or else Is_Mutably_Tagged_Type (Typ)
or else Is_Mutably_Tagged_Type (Etype (Lhs))
then
-- Create a tag check when we have the extra
-- constrained formal and it is true (meaning we
-- are not dealing with a mutably tagged object).
if Is_Entity_Name (Name (N))
and then Is_Formal (Entity (Name (N)))
and then Present
(Extra_Constrained (Entity (Name (N))))
then
Append_To (L,
Make_If_Statement (Loc,
Condition =>
New_Occurrence_Of
(Extra_Constrained
(Entity (Name (N))), Loc),
Then_Statements => New_List (
Make_Raise_Constraint_Error (Loc,
Condition =>
Make_Op_Ne (Loc,
Left_Opnd => Lhs_Tag,
Right_Opnd => Rhs_Tag),
Reason => CE_Tag_Check_Failed))));
end if;
-- Generate a tag assignment before the actual
-- assignment so we dispatch to the proper
-- assign version.
Append_To (L,
Make_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Lhs),
Selector_Name =>
Make_Identifier (Loc, Name_uTag)),
Expression =>
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Selector_Name =>
Make_Identifier (Loc, Name_uTag))));
-- Otherwise generate a normal tag check
else
Append_To (L,
Make_Raise_Constraint_Error (Loc,
Condition =>
Make_Op_Ne (Loc,
Left_Opnd => Lhs_Tag,
Right_Opnd => Rhs_Tag),
Reason => CE_Tag_Check_Failed));
end if;
end;
end if;
declare
Left_N : Node_Id := Duplicate_Subexpr (Lhs);
Right_N : Node_Id := Duplicate_Subexpr (Rhs);
begin
-- In order to dispatch the call to _assign the type of
-- the actuals must match. Add conversion (if required).
if Etype (Lhs) /= F_Typ then
Left_N := Unchecked_Convert_To (F_Typ, Left_N);
end if;
if Etype (Rhs) /= F_Typ then
Right_N := Unchecked_Convert_To (F_Typ, Right_N);
end if;
Append_To (L,
Make_Procedure_Call_Statement (Loc,
Name => New_Occurrence_Of (Op, Loc),
Parameter_Associations => New_List (
Node1 => Left_N,
Node2 => Right_N)));
end;
end;
else
L := Make_Tag_Ctrl_Assignment (N);
-- We can't afford to have destructive Finalization Actions in
-- the Self assignment case, so if the target and the source
-- are not obviously different, code is generated to avoid the
-- self assignment case:
-- if lhs'address /= rhs'address then
-- <code for controlled and/or tagged assignment>
-- end if;
-- Skip this if Restriction (No_Finalization) is active
if not Statically_Different (Lhs, Rhs)
and then Expand_Ctrl_Actions
and then not Restriction_Active (No_Finalization)
then
L := New_List (
Make_Implicit_If_Statement (N,
Condition =>
Make_Op_Ne (Loc,
Left_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (Lhs),
Attribute_Name => Name_Address),
Right_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (Rhs),
Attribute_Name => Name_Address)),
Then_Statements => L));
end if;
-- We need to set up an exception handler for implementing
-- 7.6.1(18). The remaining adjustments are tackled by the
-- implementation of adjust for record_controllers (see
-- s-finimp.adb).
-- This is skipped if we have no finalization
if Expand_Ctrl_Actions
and then not Restriction_Active (No_Finalization)
then
L := New_List (
Make_Block_Statement (Loc,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => L,
Exception_Handlers => New_List (
Make_Handler_For_Ctrl_Operation (Loc)))));
end if;
end if;
-- We will analyze the block statement with all checks suppressed
-- below, but we need elaboration checks for the primitives in the
-- case of an assignment created by the expansion of an aggregate.
if No_Finalize_Actions (N) then
Rewrite (N,
Make_Unsuppress_Block (Loc, Name_Elaboration_Check, L));
else
Rewrite (N,
Make_Block_Statement (Loc,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc, L)));
end if;
-- If no restrictions on aborts, protect the whole assignment
-- for controlled objects as per 9.8(11).
if Needs_Finalization (Typ)
and then Expand_Ctrl_Actions
and then Abort_Allowed
then
declare
Blk : constant Entity_Id :=
New_Internal_Entity
(E_Block, Current_Scope, Sloc (N), 'B');
AUD : constant Entity_Id := RTE (RE_Abort_Undefer_Direct);
begin
Set_Is_Abort_Block (N);
Set_Scope (Blk, Current_Scope);
Set_Etype (Blk, Standard_Void_Type);
Set_Identifier (N, New_Occurrence_Of (Blk, Sloc (N)));
Prepend_To (L, Build_Runtime_Call (Loc, RE_Abort_Defer));
Set_At_End_Proc (Handled_Statement_Sequence (N),
New_Occurrence_Of (AUD, Loc));
-- Present the Abort_Undefer_Direct function to the backend
-- so that it can inline the call to the function.
Add_Inlined_Body (AUD, N);
Expand_At_End_Handler
(Handled_Statement_Sequence (N), Blk);
end;
end if;
-- N has been rewritten to a block statement for which it is
-- known by construction that no checks are necessary: analyze
-- it with all checks suppressed.
Analyze (N, Suppress => All_Checks);
return;
end Tagged_Case;
-- Array types
elsif Is_Array_Type (Typ) then
declare
Actual_Rhs : Node_Id := Rhs;
begin
while Nkind (Actual_Rhs) in
N_Type_Conversion | N_Qualified_Expression
loop
Actual_Rhs := Expression (Actual_Rhs);
end loop;
Expand_Assign_Array (N, Actual_Rhs);
return;
end;
-- Record types
elsif Is_Record_Type (Typ) then
Expand_Assign_Record (N);
return;
-- Scalar types. This is where we perform the processing related to the
-- requirements of (RM 13.9.1(9-11)) concerning the handling of invalid
-- scalar values.
elsif Is_Scalar_Type (Typ) then
-- Case where right side is known valid
if Expr_Known_Valid (Rhs) then
-- Here the right side is valid, so it is fine. The case to deal
-- with is when the left side is a local variable reference whose
-- value is not currently known to be valid. If this is the case,
-- and the assignment appears in an unconditional context, then
-- we can mark the left side as now being valid if one of these
-- conditions holds:
-- The expression of the right side has Do_Range_Check set so
-- that we know a range check will be performed. Note that it
-- can be the case that a range check is omitted because we
-- make the assumption that we can assume validity for operands
-- appearing in the right side in determining whether a range
-- check is required
-- The subtype of the right side matches the subtype of the
-- left side. In this case, even though we have not checked
-- the range of the right side, we know it is in range of its
-- subtype if the expression is valid.
if Is_Local_Variable_Reference (Lhs)
and then not Is_Known_Valid (Entity (Lhs))
and then In_Unconditional_Context (N)
then
if Do_Range_Check (Rhs)
or else Etype (Lhs) = Etype (Rhs)
then
Set_Is_Known_Valid (Entity (Lhs), True);
end if;
end if;
-- Case where right side may be invalid in the sense of the RM
-- reference above. The RM does not require that we check for the
-- validity on an assignment, but it does require that the assignment
-- of an invalid value not cause erroneous behavior.
-- The general approach in GNAT is to use the Is_Known_Valid flag
-- to avoid the need for validity checking on assignments. However
-- in some cases, we have to do validity checking in order to make
-- sure that the setting of this flag is correct.
else
-- Validate right side if we are validating copies
if Validity_Checks_On
and then Validity_Check_Copies
then
-- Skip this if left-hand side is an array or record component
-- and elementary component validity checks are suppressed.
if Nkind (Lhs) in N_Selected_Component | N_Indexed_Component
and then not Validity_Check_Components
then
null;
else
Ensure_Valid (Rhs);
end if;
-- We can propagate this to the left side where appropriate
if Is_Local_Variable_Reference (Lhs)
and then not Is_Known_Valid (Entity (Lhs))
and then In_Unconditional_Context (N)
then
Set_Is_Known_Valid (Entity (Lhs), True);
end if;
-- Otherwise check to see what should be done
-- If left side is a local variable, then we just set its flag to
-- indicate that its value may no longer be valid, since we are
-- copying a potentially invalid value.
elsif Is_Local_Variable_Reference (Lhs) then
Set_Is_Known_Valid (Entity (Lhs), False);
-- Check for case of a nonlocal variable on the left side which
-- is currently known to be valid. In this case, we simply ensure
-- that the right side is valid. We only play the game of copying
-- validity status for local variables, since we are doing this
-- statically, not by tracing the full flow graph.
elsif Is_Entity_Name (Lhs)
and then Is_Known_Valid (Entity (Lhs))
then
-- Note: If Validity_Checking mode is set to none, we ignore
-- the Ensure_Valid call so don't worry about that case here.
Ensure_Valid (Rhs);
-- In all other cases, we can safely copy an invalid value without
-- worrying about the status of the left side. Since it is not a
-- variable reference it will not be considered
-- as being known to be valid in any case.
else
null;
end if;
end if;
end if;
exception
when RE_Not_Available =>
return;
end Expand_N_Assignment_Statement;
------------------------------
-- Expand_N_Block_Statement --
------------------------------
-- Encode entity names defined in block statement
procedure Expand_N_Block_Statement (N : Node_Id) is
begin
Qualify_Entity_Names (N);
end Expand_N_Block_Statement;
-----------------------------
-- Expand_N_Case_Statement --
-----------------------------
procedure Expand_N_Case_Statement (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Expr : constant Node_Id := Expression (N);
From_Cond_Expr : constant Boolean := From_Conditional_Expression (N);
Alt : Node_Id;
Len : Nat;
Cond : Node_Id;
Choice : Node_Id;
Chlist : List_Id;
function Expand_General_Case_Statement return Node_Id;
-- Expand a case statement whose selecting expression is not discrete
-----------------------------------
-- Expand_General_Case_Statement --
-----------------------------------
function Expand_General_Case_Statement return Node_Id is
-- expand into a block statement
Selector : constant Entity_Id :=
Make_Temporary (Loc, 'J');
function Selector_Subtype_Mark return Node_Id is
(New_Occurrence_Of (Etype (Expr), Loc));
Renamed_Name : constant Node_Id :=
(if Is_Name_Reference (Expr)
then Expr
else Make_Qualified_Expression (Loc,
Subtype_Mark => Selector_Subtype_Mark,
Expression => Expr));
Selector_Decl : constant Node_Id :=
Make_Object_Renaming_Declaration (Loc,
Defining_Identifier => Selector,
Subtype_Mark => Selector_Subtype_Mark,
Name => Renamed_Name);
First_Alt : constant Node_Id := First (Alternatives (N));
function Choice_Index_Decl_If_Needed return Node_Id;
-- If we are going to need a choice index object (that is, if
-- Multidefined_Bindings is true for at least one of the case
-- alternatives), then create and return that object's declaration.
-- Otherwise, return Empty; no need for a decl in that case because
-- it would never be referenced.
---------------------------------
-- Choice_Index_Decl_If_Needed --
---------------------------------
function Choice_Index_Decl_If_Needed return Node_Id is
Alt : Node_Id := First_Alt;
begin
while Present (Alt) loop
if Multidefined_Bindings (Alt) then
return Make_Object_Declaration
(Sloc => Loc,
Defining_Identifier =>
Make_Temporary (Loc, 'K'),
Object_Definition =>
New_Occurrence_Of (Standard_Positive, Loc));
end if;
Next (Alt);
end loop;
return Empty; -- decl not needed
end Choice_Index_Decl_If_Needed;
Choice_Index_Decl : constant Node_Id := Choice_Index_Decl_If_Needed;
function Pattern_Match
(Pattern : Node_Id;
Object : Node_Id;
Choice_Index : Natural;
Alt : Node_Id;
Suppress_Choice_Index_Update : Boolean := False) return Node_Id;
-- Returns a Boolean-valued expression indicating a pattern match
-- for a given pattern and object. If Choice_Index is nonzero,
-- then Choice_Index is assigned to Choice_Index_Decl (unless
-- Suppress_Choice_Index_Update is specified, which should only
-- be the case for a recursive call where the caller has already
-- taken care of the update). Pattern occurs as a choice (or as a
-- subexpression of a choice) of the case statement alternative Alt.
function Top_Level_Pattern_Match_Condition
(Alt : Node_Id) return Node_Id;
-- Returns a Boolean-valued expression indicating a pattern match
-- for the given alternative's list of choices.
-------------------
-- Pattern_Match --
-------------------
function Pattern_Match
(Pattern : Node_Id;
Object : Node_Id;
Choice_Index : Natural;
Alt : Node_Id;
Suppress_Choice_Index_Update : Boolean := False) return Node_Id
is
procedure Finish_Binding_Object_Declaration
(Component_Assoc : Node_Id; Subobject : Node_Id);
-- Finish the work that was started during analysis to
-- declare a binding object. If we are generating a copy,
-- then initialize it. If we are generating a renaming, then
-- initialize the access value designating the renamed object.
function Update_Choice_Index return Node_Id is (
Make_Assignment_Statement (Loc,
Name =>
New_Occurrence_Of
(Defining_Identifier (Choice_Index_Decl), Loc),
Expression => Make_Integer_Literal (Loc, Pos (Choice_Index))));
function PM
(Pattern : Node_Id;
Object : Node_Id;
Choice_Index : Natural := Pattern_Match.Choice_Index;
Alt : Node_Id := Pattern_Match.Alt;
Suppress_Choice_Index_Update : Boolean :=
Pattern_Match.Suppress_Choice_Index_Update) return Node_Id
renames Pattern_Match;
-- convenient rename for recursive calls
function Indexed_Element (Idx : Pos) return Node_Id;
-- Returns the Nth (well, ok, the Idxth) element of Object
---------------------------------------
-- Finish_Binding_Object_Declaration --
---------------------------------------
procedure Finish_Binding_Object_Declaration
(Component_Assoc : Node_Id; Subobject : Node_Id)
is
Decl_Chars : constant Name_Id :=
Binding_Chars (Component_Assoc);
Block_Stmt : constant Node_Id := First (Statements (Alt));
pragma Assert (Nkind (Block_Stmt) = N_Block_Statement);
pragma Assert (No (Next (Block_Stmt)));
Decl : Node_Id := First (Declarations (Block_Stmt));
Def_Id : Node_Id := Empty;
function Declare_Copy (Decl : Node_Id) return Boolean is
(Nkind (Decl) = N_Object_Declaration);
-- Declare_Copy indicates which of the two approaches
-- was chosen during analysis: declare (and initialize)
-- a new variable, or use access values to declare a renaming
-- of the appropriate subcomponent of the selector value.
function Make_Conditional (Stmt : Node_Id) return Node_Id;
-- If there is only one choice for this alternative, then
-- simply return the argument. If there is more than one
-- choice, then wrap an if-statement around the argument
-- so that it is only executed if the current choice matches.
----------------------
-- Make_Conditional --
----------------------
function Make_Conditional (Stmt : Node_Id) return Node_Id
is
Condition : Node_Id;
begin
if Present (Choice_Index_Decl) then
Condition :=
Make_Op_Eq (Loc,
New_Occurrence_Of
(Defining_Identifier (Choice_Index_Decl), Loc),
Make_Integer_Literal (Loc, Int (Choice_Index)));
return Make_If_Statement (Loc,
Condition => Condition,
Then_Statements => New_List (Stmt));
else
-- execute Stmt unconditionally
return Stmt;
end if;
end Make_Conditional;
begin
-- find the variable to be modified (and its declaration)
loop
if Nkind (Decl) in N_Object_Declaration
| N_Object_Renaming_Declaration
then
Def_Id := Defining_Identifier (Decl);
exit when Chars (Def_Id) = Decl_Chars;
end if;
Next (Decl);
pragma Assert (Present (Decl));
end loop;
-- For a binding object, we sometimes make a copy and
-- sometimes introduce a renaming. That decision is made
-- elsewhere. The renaming case involves dereferencing an
-- access value because of the possibility of multiple
-- choices (with multiple binding definitions) for a single
-- alternative. In the copy case, we initialize the copy
-- here (conditionally if there are multiple choices); in the
-- renaming case, we initialize (again, maybe conditionally)
-- the access value.
if Declare_Copy (Decl) then
declare
Assign_Value : constant Node_Id :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Def_Id, Loc),
Expression => Subobject);
HSS : constant Node_Id :=
Handled_Statement_Sequence (Block_Stmt);
begin
Prepend (Make_Conditional (Assign_Value),
Statements (HSS));
Set_Analyzed (HSS, False);
end;
else
pragma Assert (Nkind (Name (Decl)) = N_Explicit_Dereference);
declare
Ptr_Obj : constant Entity_Id :=
Entity (Prefix (Name (Decl)));
Ptr_Decl : constant Node_Id := Parent (Ptr_Obj);
Assign_Reference : constant Node_Id :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Ptr_Obj, Loc),
Expression =>
Make_Attribute_Reference (Loc,
Prefix => Subobject,
Attribute_Name => Name_Unrestricted_Access));
begin
Insert_After
(After => Ptr_Decl,
Node => Make_Conditional (Assign_Reference));
if Present (Expression (Ptr_Decl)) then
-- Delete bogus initial value built during analysis.
-- Look for "5432" in sem_case.adb.
pragma Assert (Nkind (Expression (Ptr_Decl)) =
N_Unchecked_Type_Conversion);
Set_Expression (Ptr_Decl, Empty);
end if;
end;
end if;
Set_Analyzed (Block_Stmt, False);
end Finish_Binding_Object_Declaration;
---------------------
-- Indexed_Element --
---------------------
function Indexed_Element (Idx : Pos) return Node_Id is
Obj_Index : constant Node_Id :=
Make_Op_Add (Loc,
Left_Opnd =>
Make_Attribute_Reference (Loc,
Attribute_Name => Name_First,
Prefix => New_Copy_Tree (Object)),
Right_Opnd =>
Make_Integer_Literal (Loc, Idx - 1));
begin
return Make_Indexed_Component (Loc,
Prefix => New_Copy_Tree (Object),
Expressions => New_List (Obj_Index));
end Indexed_Element;
-- Start of processing for Pattern_Match
begin
if Choice_Index /= 0 and not Suppress_Choice_Index_Update then
pragma Assert (Present (Choice_Index_Decl));
-- Add Choice_Index update as a side effect of evaluating
-- this condition and try again, this time suppressing
-- Choice_Index update.
return Make_Expression_With_Actions (Loc,
Actions => New_List (Update_Choice_Index),
Expression =>
PM (Pattern, Object,
Suppress_Choice_Index_Update => True));
end if;
if Nkind (Pattern) in N_Has_Etype
and then Is_Discrete_Type (Etype (Pattern))
and then Compile_Time_Known_Value (Pattern)
then
declare
Val : Node_Id;
begin
if Is_Enumeration_Type (Etype (Pattern)) then
Val := Get_Enum_Lit_From_Pos
(Etype (Pattern), Expr_Value (Pattern), Loc);
else
Val := Make_Integer_Literal (Loc, Expr_Value (Pattern));
end if;
return Make_Op_Eq (Loc, Object, Val);
end;
end if;
case Nkind (Pattern) is
when N_Aggregate =>
declare
Result : Node_Id;
begin
if Is_Array_Type (Etype (Pattern)) then
-- Nonpositional aggregates currently unimplemented.
-- We flag that case during analysis, so an assertion
-- is ok here.
--
pragma Assert
(Is_Empty_List (Component_Associations (Pattern)));
declare
Agg_Length : constant Node_Id :=
Make_Integer_Literal (Loc,
List_Length (Expressions (Pattern)));
Obj_Length : constant Node_Id :=
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Length,
Prefix => New_Copy_Tree (Object));
begin
Result := Make_Op_Eq (Loc,
Left_Opnd => Obj_Length,
Right_Opnd => Agg_Length);
end;
declare
Expr : Node_Id := First (Expressions (Pattern));
Idx : Pos := 1;
begin
while Present (Expr) loop
Result :=
Make_And_Then (Loc,
Left_Opnd => Result,
Right_Opnd =>
PM (Pattern => Expr,
Object => Indexed_Element (Idx)));
Next (Expr);
Idx := Idx + 1;
end loop;
end;
return Result;
end if;
-- positional notation should have been normalized
pragma Assert (No (Expressions (Pattern)));
declare
Component_Assoc : Node_Id
:= First (Component_Associations (Pattern));
Choice : Node_Id;
function Subobject return Node_Id is
(Make_Selected_Component (Loc,
Prefix => New_Copy_Tree (Object),
Selector_Name => New_Occurrence_Of
(Entity (Choice), Loc)));
begin
Result := New_Occurrence_Of (Standard_True, Loc);
while Present (Component_Assoc) loop
Choice := First (Choices (Component_Assoc));
while Present (Choice) loop
pragma Assert
(Is_Entity_Name (Choice)
and then Ekind (Entity (Choice))
in E_Discriminant | E_Component);
if Box_Present (Component_Assoc) then
-- Box matches anything
pragma Assert
(No (Expression (Component_Assoc)));
else
Result := Make_And_Then (Loc,
Left_Opnd => Result,
Right_Opnd =>
PM (Pattern =>
Expression
(Component_Assoc),
Object => Subobject));
end if;
-- If this component association defines
-- (in the case where the pattern matches)
-- the value of a binding object, then
-- prepend to the statement list for this
-- alternative an assignment to the binding
-- object. This assignment will be conditional
-- if there is more than one choice.
if Binding_Chars (Component_Assoc) /= No_Name
then
Finish_Binding_Object_Declaration
(Component_Assoc => Component_Assoc,
Subobject => Subobject);
end if;
Next (Choice);
end loop;
Next (Component_Assoc);
end loop;
end;
return Result;
end;
when N_String_Literal =>
return Result : Node_Id do
declare
Char_Type : constant Entity_Id :=
Root_Type (Component_Type (Etype (Pattern)));
-- If the component type is not a standard character
-- type then this string lit should have already been
-- transformed into an aggregate in
-- Resolve_String_Literal.
--
pragma Assert (Is_Standard_Character_Type (Char_Type));
Str : constant String_Id := Strval (Pattern);
Strlen : constant Nat := String_Length (Str);
Lit_Length : constant Node_Id :=
Make_Integer_Literal (Loc, Strlen);
Obj_Length : constant Node_Id :=
Make_Attribute_Reference (Loc,
Attribute_Name => Name_Length,
Prefix => New_Copy_Tree (Object));
begin
Result := Make_Op_Eq (Loc,
Left_Opnd => Obj_Length,
Right_Opnd => Lit_Length);
for Idx in 1 .. Strlen loop
declare
C : constant Char_Code :=
Get_String_Char (Str, Idx);
Obj_Element : constant Node_Id :=
Indexed_Element (Idx);
Char_Lit : Node_Id;
begin
Set_Character_Literal_Name (C);
Char_Lit :=
Make_Character_Literal (Loc,
Chars => Name_Find,
Char_Literal_Value => UI_From_CC (C));
Result :=
Make_And_Then (Loc,
Left_Opnd => Result,
Right_Opnd =>
Make_Op_Eq (Loc,
Left_Opnd => Obj_Element,
Right_Opnd => Char_Lit));
end;
end loop;
end;
end return;
when N_Qualified_Expression =>
return Make_And_Then (Loc,
Left_Opnd => Make_In (Loc,
Left_Opnd => New_Copy_Tree (Object),
Right_Opnd => New_Copy_Tree (Subtype_Mark (Pattern))),
Right_Opnd =>
PM (Pattern => Expression (Pattern),
Object => New_Copy_Tree (Object)));
when N_Identifier | N_Expanded_Name =>
if Is_Type (Entity (Pattern)) then
return Make_In (Loc,
Left_Opnd => New_Copy_Tree (Object),
Right_Opnd => New_Occurrence_Of
(Entity (Pattern), Loc));
elsif Ekind (Entity (Pattern)) = E_Constant then
return PM (Pattern =>
Expression (Parent (Entity (Pattern))),
Object => Object);
end if;
when N_Others_Choice =>
return New_Occurrence_Of (Standard_True, Loc);
when N_Type_Conversion =>
-- aggregate expansion sometimes introduces conversions
if not Comes_From_Source (Pattern)
and then Base_Type (Etype (Pattern))
= Base_Type (Etype (Expression (Pattern)))
then
return PM (Expression (Pattern), Object);
end if;
when others =>
null;
end case;
-- Avoid cascading errors
pragma Assert (Serious_Errors_Detected > 0);
return New_Occurrence_Of (Standard_True, Loc);
end Pattern_Match;
---------------------------------------
-- Top_Level_Pattern_Match_Condition --
---------------------------------------
function Top_Level_Pattern_Match_Condition
(Alt : Node_Id) return Node_Id
is
Top_Level_Object : constant Node_Id :=
New_Occurrence_Of (Selector, Loc);
Choices : constant List_Id := Discrete_Choices (Alt);
First_Choice : constant Node_Id := First (Choices);
Subsequent : Node_Id := Next (First_Choice);
Choice_Index : Natural := 0;
begin
if Multidefined_Bindings (Alt) then
Choice_Index := 1;
end if;
return Result : Node_Id :=
Pattern_Match (Pattern => First_Choice,
Object => Top_Level_Object,
Choice_Index => Choice_Index,
Alt => Alt)
do
while Present (Subsequent) loop
if Choice_Index /= 0 then
Choice_Index := Choice_Index + 1;
end if;
Result := Make_Or_Else (Loc,
Left_Opnd => Result,
Right_Opnd => Pattern_Match
(Pattern => Subsequent,
Object => Top_Level_Object,
Choice_Index => Choice_Index,
Alt => Alt));
Subsequent := Next (Subsequent);
end loop;
end return;
end Top_Level_Pattern_Match_Condition;
function Elsif_Parts return List_Id;
-- Process subsequent alternatives
-----------------
-- Elsif_Parts --
-----------------
function Elsif_Parts return List_Id is
Alt : Node_Id := First_Alt;
Result : constant List_Id := New_List;
begin
loop
Alt := Next (Alt);
exit when No (Alt);
Append (Make_Elsif_Part (Loc,
Condition => Top_Level_Pattern_Match_Condition (Alt),
Then_Statements => Statements (Alt)),
Result);
end loop;
return Result;
end Elsif_Parts;
function Else_Statements return List_Id;
-- Returns a "raise Constraint_Error" statement if
-- exception propagate is permitted and No_List otherwise.
---------------------
-- Else_Statements --
---------------------
function Else_Statements return List_Id is
begin
if Restriction_Active (No_Exception_Propagation) then
return No_List;
else
return New_List (Make_Raise_Constraint_Error (Loc,
Reason => CE_Invalid_Data));
end if;
end Else_Statements;
-- Local constants
If_Stmt : constant Node_Id :=
Make_If_Statement (Loc,
Condition => Top_Level_Pattern_Match_Condition (First_Alt),
Then_Statements => Statements (First_Alt),
Elsif_Parts => Elsif_Parts,
Else_Statements => Else_Statements);
Declarations : constant List_Id := New_List (Selector_Decl);
-- Start of processing for Expand_General_Case_Statement
begin
if Present (Choice_Index_Decl) then
Append_To (Declarations, Choice_Index_Decl);
end if;
return Make_Block_Statement (Loc,
Declarations => Declarations,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (If_Stmt)));
end Expand_General_Case_Statement;
-- Start of processing for Expand_N_Case_Statement
begin
if Core_Extensions_Allowed
and then not Is_Discrete_Type (Etype (Expr))
then
Rewrite (N, Expand_General_Case_Statement);
Analyze (N);
return;
end if;
-- Check for the situation where we know at compile time which branch
-- will be taken.
-- If the value is static but its subtype is predicated and the value
-- does not obey the predicate, the value is marked non-static, and
-- there can be no corresponding static alternative. In that case we
-- replace the case statement with an exception, regardless of whether
-- assertions are enabled or not, unless predicates are ignored.
if Compile_Time_Known_Value (Expr)
and then Has_Predicates (Etype (Expr))
and then not Predicates_Ignored (Etype (Expr))
and then not Is_OK_Static_Expression (Expr)
then
Rewrite (N,
Make_Raise_Constraint_Error (Loc, Reason => CE_Invalid_Data));
Analyze (N);
return;
elsif Compile_Time_Known_Value (Expr)
and then (not Has_Predicates (Etype (Expr))
or else Is_Static_Expression (Expr))
then
Alt := Find_Static_Alternative (N);
-- Do not consider controlled objects found in a case statement which
-- actually models a case expression because their early finalization
-- will affect the result of the expression.
if not From_Conditional_Expression (N) then
Process_Statements_For_Controlled_Objects (Alt);
end if;
-- Move statements from this alternative after the case statement.
-- They are already analyzed, so will be skipped by the analyzer.
Insert_List_After (N, Statements (Alt));
-- That leaves the case statement as a shell. So now we can kill all
-- other alternatives in the case statement.
Kill_Dead_Code (Expression (N));
declare
Dead_Alt : Node_Id;
begin
-- Loop through case alternatives, skipping pragmas, and skipping
-- the one alternative that we select (and therefore retain).
Dead_Alt := First (Alternatives (N));
while Present (Dead_Alt) loop
if Dead_Alt /= Alt
and then Nkind (Dead_Alt) = N_Case_Statement_Alternative
then
Kill_Dead_Code (Statements (Dead_Alt), Warn_On_Deleted_Code);
end if;
Next (Dead_Alt);
end loop;
end;
Rewrite (N, Make_Null_Statement (Loc));
return;
end if;
-- Here if the choice is not determined at compile time
declare
Last_Alt : constant Node_Id := Last (Alternatives (N));
Others_Present : Boolean;
Others_Node : Node_Id;
Then_Stms : List_Id;
Else_Stms : List_Id;
begin
if Nkind (First (Discrete_Choices (Last_Alt))) = N_Others_Choice then
Others_Present := True;
Others_Node := Last_Alt;
else
Others_Present := False;
end if;
-- First step is to worry about possible invalid argument. The RM
-- requires (RM 4.5.7 (21/3) and 5.4 (13)) that if the result is
-- invalid (e.g. it is outside the base range), then Constraint_Error
-- must be raised.
-- Case of validity check required (validity checks are on, the
-- expression is not known to be valid, and the case statement
-- comes from source -- no need to validity check internally
-- generated case statements).
if Validity_Check_Default
and then not Predicates_Ignored (Etype (Expr))
then
-- Recognize the simple case where Expr is an object reference
-- and the case statement is directly preceded by an
-- "if Obj'Valid then": in this case, do not emit another validity
-- check.
declare
Check_Validity : Boolean := True;
Attr : Node_Id;
begin
if Nkind (Expr) = N_Identifier
and then Nkind (Parent (N)) = N_If_Statement
and then Nkind (Original_Node (Condition (Parent (N))))
= N_Attribute_Reference
and then No (Prev (N))
then
Attr := Original_Node (Condition (Parent (N)));
if Attribute_Name (Attr) = Name_Valid
and then Nkind (Prefix (Attr)) = N_Identifier
and then Entity (Prefix (Attr)) = Entity (Expr)
then
Check_Validity := False;
end if;
end if;
if Check_Validity then
Ensure_Valid (Expr);
end if;
end;
end if;
-- If there is only a single alternative, just replace it with the
-- sequence of statements since obviously that is what is going to
-- be executed in all cases, except if it is the node to be wrapped
-- by a transient scope, because this would cause the sequence of
-- statements to be leaked out of the transient scope.
Len := List_Length (Alternatives (N));
if Len = 1
and then not (Scope_Is_Transient and then Node_To_Be_Wrapped = N)
then
-- We still need to evaluate the expression if it has any side
-- effects.
Remove_Side_Effects (Expression (N));
Alt := First (Alternatives (N));
-- Do not consider controlled objects found in a case statement
-- which actually models a case expression because their early
-- finalization will affect the result of the expression.
if not From_Conditional_Expression (N) then
Process_Statements_For_Controlled_Objects (Alt);
end if;
Insert_List_After (N, Statements (Alt));
-- That leaves the case statement as a shell. The alternative that
-- will be executed is reset to a null list. So now we can kill
-- the entire case statement.
Kill_Dead_Code (Expression (N));
Rewrite (N, Make_Null_Statement (Loc));
return;
-- An optimization. If there are only two alternatives, and only
-- a single choice, then rewrite the whole case statement as an
-- if statement, since this can result in subsequent optimizations.
-- This helps not only with case statements in the source of a
-- simple form, but also with generated code (discriminant check
-- functions in particular).
-- Note: it is OK to do this before expanding out choices for any
-- static predicates, since the if statement processing will handle
-- the static predicate case fine.
elsif Len = 2 then
Chlist := Discrete_Choices (First (Alternatives (N)));
if List_Length (Chlist) = 1 then
Choice := First (Chlist);
Then_Stms := Statements (First (Alternatives (N)));
Else_Stms := Statements (Last (Alternatives (N)));
-- For TRUE, generate "expression", not expression = true
if Nkind (Choice) = N_Identifier
and then Entity (Choice) = Standard_True
then
Cond := Expression (N);
-- For FALSE, generate "expression" and switch then/else
elsif Nkind (Choice) = N_Identifier
and then Entity (Choice) = Standard_False
then
Cond := Expression (N);
Else_Stms := Statements (First (Alternatives (N)));
Then_Stms := Statements (Last (Alternatives (N)));
-- For a range, generate "expression in range"
elsif Nkind (Choice) = N_Range
or else (Nkind (Choice) = N_Attribute_Reference
and then Attribute_Name (Choice) = Name_Range)
or else (Is_Entity_Name (Choice)
and then Is_Type (Entity (Choice)))
then
Cond :=
Make_In (Loc,
Left_Opnd => Expression (N),
Right_Opnd => Relocate_Node (Choice));
-- A subtype indication is not a legal operator in a membership
-- test, so retrieve its range.
elsif Nkind (Choice) = N_Subtype_Indication then
Cond :=
Make_In (Loc,
Left_Opnd => Expression (N),
Right_Opnd =>
Relocate_Node
(Range_Expression (Constraint (Choice))));
-- For any other subexpression "expression = value"
else
Cond :=
Make_Op_Eq (Loc,
Left_Opnd => Expression (N),
Right_Opnd => Relocate_Node (Choice));
end if;
-- Now rewrite the case as an IF
Rewrite (N,
Make_If_Statement (Loc,
Condition => Cond,
Then_Statements => Then_Stms,
Else_Statements => Else_Stms));
-- The rewritten if statement needs to inherit whether the
-- case statement was expanded from a conditional expression,
-- for proper handling of nested controlled objects.
Set_From_Conditional_Expression (N, From_Cond_Expr);
Analyze (N);
return;
end if;
end if;
-- If the last alternative is not an Others choice, replace it with
-- an N_Others_Choice. Note that we do not bother to call Analyze on
-- the modified case statement, since it's only effect would be to
-- compute the contents of the Others_Discrete_Choices which is not
-- needed by the back end anyway.
-- The reason for this is that the back end always needs some default
-- for a switch, so if we have not supplied one in the processing
-- above for validity checking, then we need to supply one here.
if not Others_Present then
Others_Node := Make_Others_Choice (Sloc (Last_Alt));
-- If Predicates_Ignored is true the value does not satisfy the
-- predicate, and there is no Others choice, Constraint_Error
-- must be raised (RM 4.5.7 (21/3) and 5.4 (13)).
if Predicates_Ignored (Etype (Expr)) then
declare
Except : constant Node_Id :=
Make_Raise_Constraint_Error (Loc,
Reason => CE_Invalid_Data);
New_Alt : constant Node_Id :=
Make_Case_Statement_Alternative (Loc,
Discrete_Choices => New_List (
Make_Others_Choice (Loc)),
Statements => New_List (Except));
begin
Append (New_Alt, Alternatives (N));
Analyze_And_Resolve (Except);
end;
else
Set_Others_Discrete_Choices
(Others_Node, Discrete_Choices (Last_Alt));
Set_Discrete_Choices (Last_Alt, New_List (Others_Node));
end if;
end if;
-- Deal with possible declarations of controlled objects, and also
-- with rewriting choice sequences for static predicate references.
Alt := First_Non_Pragma (Alternatives (N));
while Present (Alt) loop
-- Do not consider controlled objects found in a case statement
-- which actually models a case expression because their early
-- finalization will affect the result of the expression.
if not From_Conditional_Expression (N) then
Process_Statements_For_Controlled_Objects (Alt);
end if;
if Has_SP_Choice (Alt) then
Expand_Static_Predicates_In_Choices (Alt);
end if;
Next_Non_Pragma (Alt);
end loop;
end;
end Expand_N_Case_Statement;
-----------------------------
-- Expand_N_Exit_Statement --
-----------------------------
-- The only processing required is to deal with a possible C/Fortran
-- boolean value used as the condition for the exit statement.
procedure Expand_N_Exit_Statement (N : Node_Id) is
begin
Adjust_Condition (Condition (N));
end Expand_N_Exit_Statement;
----------------------------------
-- Expand_Formal_Container_Loop --
----------------------------------
procedure Expand_Formal_Container_Loop (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Isc : constant Node_Id := Iteration_Scheme (N);
I_Spec : constant Node_Id := Iterator_Specification (Isc);
Cursor : constant Entity_Id := Defining_Identifier (I_Spec);
Container : constant Node_Id := Entity (Name (I_Spec));
Stats : constant List_Id := Statements (N);
Advance : Node_Id;
Init_Decl : Node_Id;
Init_Name : Entity_Id;
New_Loop : Node_Id;
begin
-- The expansion of a formal container loop resembles the one for Ada
-- containers. The only difference is that the primitives mention the
-- domain of iteration explicitly, and function First applied to the
-- container yields a cursor directly.
-- Cursor : Cursor_type := First (Container);
-- while Has_Element (Cursor, Container) loop
-- <original loop statements>
-- Cursor := Next (Container, Cursor);
-- end loop;
Build_Formal_Container_Iteration
(N, Container, Cursor, Init_Decl, Advance, New_Loop);
Append_To (Stats, Advance);
-- Build a block to capture declaration of the cursor
Rewrite (N,
Make_Block_Statement (Loc,
Declarations => New_List (Init_Decl),
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (New_Loop))));
-- The loop parameter is declared by an object declaration, but within
-- the loop we must prevent user assignments to it, so we analyze the
-- declaration and reset the entity kind, before analyzing the rest of
-- the loop.
Analyze (Init_Decl);
Init_Name := Defining_Identifier (Init_Decl);
Reinit_Field_To_Zero (Init_Name, F_Has_Initial_Value,
Old_Ekind => (E_Variable => True, others => False));
Reinit_Field_To_Zero (Init_Name, F_Is_Elaboration_Checks_OK_Id);
Reinit_Field_To_Zero (Init_Name, F_Is_Elaboration_Warnings_OK_Id);
Reinit_Field_To_Zero (Init_Name, F_SPARK_Pragma);
Reinit_Field_To_Zero (Init_Name, F_SPARK_Pragma_Inherited);
Mutate_Ekind (Init_Name, E_Loop_Parameter);
-- Wrap the block statements with the condition specified in the
-- iterator filter when one is present.
if Present (Iterator_Filter (I_Spec)) then
pragma Assert (Ada_Version >= Ada_2022);
Set_Statements (Handled_Statement_Sequence (N),
New_List (Make_If_Statement (Loc,
Condition => Iterator_Filter (I_Spec),
Then_Statements =>
Statements (Handled_Statement_Sequence (N)))));
end if;
-- The cursor was marked as a loop parameter to prevent user assignments
-- to it, however this renders the advancement step illegal as it is not
-- possible to change the value of a constant. Flag the advancement step
-- as a legal form of assignment to remedy this side effect.
Set_Assignment_OK (Name (Advance));
Analyze (N);
-- Because we have to analyze the initial declaration of the loop
-- parameter multiple times its scope is incorrectly set at this point
-- to the one surrounding the block statement - so set the scope
-- manually to be the actual block statement, and indicate that it is
-- not visible after the block has been analyzed.
Set_Scope (Init_Name, Entity (Identifier (N)));
Set_Is_Immediately_Visible (Init_Name, False);
end Expand_Formal_Container_Loop;
------------------------------------------
-- Expand_Formal_Container_Element_Loop --
------------------------------------------
procedure Expand_Formal_Container_Element_Loop (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Isc : constant Node_Id := Iteration_Scheme (N);
I_Spec : constant Node_Id := Iterator_Specification (Isc);
Element : constant Entity_Id := Defining_Identifier (I_Spec);
Container : constant Node_Id := Entity (Name (I_Spec));
Container_Typ : constant Entity_Id := Base_Type (Etype (Container));
Stats : constant List_Id := Statements (N);
Cursor : constant Entity_Id :=
Make_Defining_Identifier (Loc,
Chars => New_External_Name (Chars (Element), 'C'));
Elmt_Decl : Node_Id;
Element_Op : constant Entity_Id :=
Get_Iterable_Type_Primitive (Container_Typ, Name_Element);
Advance : Node_Id;
Init : Node_Id;
New_Loop : Node_Id;
Block : Node_Id;
begin
-- For an element iterator, the Element aspect must be present,
-- (this is checked during analysis).
-- We create a block to hold a variable declaration initialized with
-- a call to Element, and generate:
-- Cursor : Cursor_Type := First (Container);
-- while Has_Element (Cursor, Container) loop
-- declare
-- Elmt : Element_Type := Element (Container, Cursor);
-- begin
-- <original loop statements>
-- Cursor := Next (Container, Cursor);
-- end;
-- end loop;
Build_Formal_Container_Iteration
(N, Container, Cursor, Init, Advance, New_Loop);
Mutate_Ekind (Cursor, E_Variable);
Insert_Action (N, Init);
-- The loop parameter is declared by an object declaration, but within
-- the loop we must prevent user assignments to it; the following flag
-- accomplishes that.
Set_Is_Loop_Parameter (Element);
-- Declaration for Element
Elmt_Decl :=
Make_Object_Declaration (Loc,
Defining_Identifier => Element,
Object_Definition => New_Occurrence_Of (Etype (Element_Op), Loc));
Set_Expression (Elmt_Decl,
Make_Function_Call (Loc,
Name => New_Occurrence_Of (Element_Op, Loc),
Parameter_Associations => New_List (
Convert_To_Iterable_Type (Container, Loc),
New_Occurrence_Of (Cursor, Loc))));
Block :=
Make_Block_Statement (Loc,
Declarations => New_List (Elmt_Decl),
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => Stats));
-- Wrap the block statements with the condition specified in the
-- iterator filter when one is present.
if Present (Iterator_Filter (I_Spec)) then
pragma Assert (Ada_Version >= Ada_2022);
Set_Statements (Handled_Statement_Sequence (Block),
New_List (
Make_If_Statement (Loc,
Condition => Iterator_Filter (I_Spec),
Then_Statements =>
Statements (Handled_Statement_Sequence (Block))),
Advance));
else
Append_To (Stats, Advance);
end if;
Set_Statements (New_Loop, New_List (Block));
-- The element is only modified in expanded code, so it appears as
-- unassigned to the warning machinery. We must suppress this spurious
-- warning explicitly.
Set_Warnings_Off (Element);
Rewrite (N, New_Loop);
Analyze (N);
end Expand_Formal_Container_Element_Loop;
----------------------------------
-- Expand_N_Goto_When_Statement --
----------------------------------
procedure Expand_N_Goto_When_Statement (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
begin
Rewrite (N,
Make_If_Statement (Loc,
Condition => Condition (N),
Then_Statements => New_List (
Make_Goto_Statement (Loc,
Name => Name (N)))));
Analyze (N);
end Expand_N_Goto_When_Statement;
---------------------------
-- Expand_N_If_Statement --
---------------------------
-- First we deal with the case of C and Fortran convention boolean values,
-- with zero/nonzero semantics.
-- Second, we deal with the obvious rewriting for the cases where the
-- condition of the IF is known at compile time to be True or False.
-- Third, we remove elsif parts which have non-empty Condition_Actions and
-- rewrite as independent if statements. For example:
-- if x then xs
-- elsif y then ys
-- ...
-- end if;
-- becomes
--
-- if x then xs
-- else
-- <<condition actions of y>>
-- if y then ys
-- ...
-- end if;
-- end if;
-- This rewriting is needed if at least one elsif part has a non-empty
-- Condition_Actions list. We also do the same processing if there is a
-- constant condition in an elsif part (in conjunction with the first
-- processing step mentioned above, for the recursive call made to deal
-- with the created inner if, this deals with properly optimizing the
-- cases of constant elsif conditions).
procedure Expand_N_If_Statement (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Hed : Node_Id;
E : Node_Id;
New_If : Node_Id;
Warn_If_Deleted : constant Boolean :=
Warn_On_Deleted_Code and then Comes_From_Source (N);
-- Indicates whether we want warnings when we delete branches of the
-- if statement based on constant condition analysis. We never want
-- these warnings for expander generated code.
begin
-- Do not consider controlled objects found in an if statement which
-- actually models an if expression because their early finalization
-- will affect the result of the expression.
if not From_Conditional_Expression (N) then
Process_Statements_For_Controlled_Objects (N);
end if;
Adjust_Condition (Condition (N));
-- The following loop deals with constant conditions for the IF. We
-- need a loop because as we eliminate False conditions, we grab the
-- first elsif condition and use it as the primary condition.
while Compile_Time_Known_Value (Condition (N)) loop
-- If condition is True, we can simply rewrite the if statement now
-- by replacing it by the series of then statements.
if Is_True (Expr_Value (Condition (N))) then
-- All the else parts can be killed
Kill_Dead_Code (Elsif_Parts (N), Warn_If_Deleted);
Kill_Dead_Code (Else_Statements (N), Warn_If_Deleted);
Hed := Remove_Head (Then_Statements (N));
Insert_List_After (N, Then_Statements (N));
Rewrite (N, Hed);
return;
-- If condition is False, then we can delete the condition and
-- the Then statements
else
-- We do not delete the condition if constant condition warnings
-- are enabled, since otherwise we end up deleting the desired
-- warning. Of course the backend will get rid of this True/False
-- test anyway, so nothing is lost here.
if not Constant_Condition_Warnings then
Kill_Dead_Code (Condition (N));
end if;
Kill_Dead_Code (Then_Statements (N), Warn_If_Deleted);
-- If there are no elsif statements, then we simply replace the
-- entire if statement by the sequence of else statements.
if No (Elsif_Parts (N)) then
if Is_Empty_List (Else_Statements (N)) then
Rewrite (N,
Make_Null_Statement (Sloc (N)));
else
Hed := Remove_Head (Else_Statements (N));
Insert_List_After (N, Else_Statements (N));
Rewrite (N, Hed);
end if;
return;
-- If there are elsif statements, the first of them becomes the
-- if/then section of the rebuilt if statement This is the case
-- where we loop to reprocess this copied condition.
else
Hed := Remove_Head (Elsif_Parts (N));
Insert_Actions (N, Condition_Actions (Hed));
Set_Condition (N, Condition (Hed));
Set_Then_Statements (N, Then_Statements (Hed));
-- Hed might have been captured as the condition determining
-- the current value for an entity. Now it is detached from
-- the tree, so a Current_Value pointer in the condition might
-- need to be updated.
Set_Current_Value_Condition (N);
if Is_Empty_List (Elsif_Parts (N)) then
Set_Elsif_Parts (N, No_List);
end if;
end if;
end if;
end loop;
-- Loop through elsif parts, dealing with constant conditions and
-- possible condition actions that are present.
E := First (Elsif_Parts (N));
while Present (E) loop
-- Do not consider controlled objects found in an if statement which
-- actually models an if expression because their early finalization
-- will affect the result of the expression.
if not From_Conditional_Expression (N) then
Process_Statements_For_Controlled_Objects (E);
end if;
Adjust_Condition (Condition (E));
-- If there are condition actions, then rewrite the if statement as
-- indicated above. We also do the same rewrite for a True or False
-- condition. The further processing of this constant condition is
-- then done by the recursive call to expand the newly created if
-- statement
if Present (Condition_Actions (E))
or else Compile_Time_Known_Value (Condition (E))
then
New_If :=
Make_If_Statement (Sloc (E),
Condition => Condition (E),
Then_Statements => Then_Statements (E),
Elsif_Parts => No_List,
Else_Statements => Else_Statements (N));
-- Elsif parts for new if come from remaining elsif's of parent
while Present (Next (E)) loop
if No (Elsif_Parts (New_If)) then
Set_Elsif_Parts (New_If, New_List);
end if;
Append (Remove_Next (E), Elsif_Parts (New_If));
end loop;
Set_Else_Statements (N, New_List (New_If));
Insert_List_Before (New_If, Condition_Actions (E));
Remove (E);
if Is_Empty_List (Elsif_Parts (N)) then
Set_Elsif_Parts (N, No_List);
end if;
Analyze (New_If);
-- Note this is not an implicit if statement, since it is part of
-- an explicit if statement in the source (or of an implicit if
-- statement that has already been tested). We set the flag after
-- calling Analyze to avoid generating extra warnings specific to
-- pure if statements, however (see Sem_Ch5.Analyze_If_Statement).
Preserve_Comes_From_Source (New_If, N);
return;
-- No special processing for that elsif part, move to next
else
Next (E);
end if;
end loop;
-- Some more optimizations applicable if we still have an IF statement
if Nkind (N) /= N_If_Statement then
return;
end if;
-- Another optimization, special cases that can be simplified
-- if expression then
-- return [standard.]true;
-- else
-- return [standard.]false;
-- end if;
-- can be changed to:
-- return expression;
-- and
-- if expression then
-- return [standard.]false;
-- else
-- return [standard.]true;
-- end if;
-- can be changed to:
-- return not (expression);
-- Do these optimizations only for internally generated code and only
-- when -fpreserve-control-flow isn't set, to preserve the original
-- source control flow.
if not Comes_From_Source (N)
and then not Opt.Suppress_Control_Flow_Optimizations
and then Nkind (N) = N_If_Statement
and then No (Elsif_Parts (N))
and then List_Length (Then_Statements (N)) = 1
and then List_Length (Else_Statements (N)) = 1
then
declare
Then_Stm : constant Node_Id := First (Then_Statements (N));
Else_Stm : constant Node_Id := First (Else_Statements (N));
Then_Expr : Node_Id;
Else_Expr : Node_Id;
begin
if Nkind (Then_Stm) = N_Simple_Return_Statement
and then
Nkind (Else_Stm) = N_Simple_Return_Statement
then
Then_Expr := Expression (Then_Stm);
Else_Expr := Expression (Else_Stm);
if Nkind (Then_Expr) in N_Expanded_Name | N_Identifier
and then
Nkind (Else_Expr) in N_Expanded_Name | N_Identifier
then
if Entity (Then_Expr) = Standard_True
and then Entity (Else_Expr) = Standard_False
then
Rewrite (N,
Make_Simple_Return_Statement (Loc,
Expression => Relocate_Node (Condition (N))));
Analyze (N);
elsif Entity (Then_Expr) = Standard_False
and then Entity (Else_Expr) = Standard_True
then
Rewrite (N,
Make_Simple_Return_Statement (Loc,
Expression =>
Make_Op_Not (Loc,
Right_Opnd => Relocate_Node (Condition (N)))));
Analyze (N);
end if;
end if;
end if;
end;
end if;
end Expand_N_If_Statement;
--------------------------
-- Expand_Iterator_Loop --
--------------------------
procedure Expand_Iterator_Loop (N : Node_Id) is
Isc : constant Node_Id := Iteration_Scheme (N);
I_Spec : constant Node_Id := Iterator_Specification (Isc);
Container : constant Node_Id := Name (I_Spec);
Container_Typ : constant Entity_Id := Base_Type (Etype (Container));
begin
-- Processing for arrays
if Is_Array_Type (Container_Typ) then
pragma Assert (Of_Present (I_Spec));
Expand_Iterator_Loop_Over_Array (N);
elsif Has_Aspect (Container_Typ, Aspect_Iterable) then
if Of_Present (I_Spec) then
Expand_Formal_Container_Element_Loop (N);
else
Expand_Formal_Container_Loop (N);
end if;
-- Processing for containers
else
Expand_Iterator_Loop_Over_Container
(N, I_Spec, Container, Container_Typ);
end if;
end Expand_Iterator_Loop;
-------------------------------------
-- Expand_Iterator_Loop_Over_Array --
-------------------------------------
procedure Expand_Iterator_Loop_Over_Array (N : Node_Id) is
Isc : constant Node_Id := Iteration_Scheme (N);
I_Spec : constant Node_Id := Iterator_Specification (Isc);
Array_Node : constant Node_Id := Name (I_Spec);
Array_Typ : constant Entity_Id := Base_Type (Etype (Array_Node));
Array_Dim : constant Pos := Number_Dimensions (Array_Typ);
Id : constant Entity_Id := Defining_Identifier (I_Spec);
Loc : constant Source_Ptr := Sloc (Isc);
Stats : List_Id := Statements (N);
Core_Loop : Node_Id;
Dim1 : Int;
Ind_Comp : Node_Id;
Iterator : Entity_Id;
begin
if Present (Iterator_Filter (I_Spec)) then
pragma Assert (Ada_Version >= Ada_2022);
Stats := New_List (Make_If_Statement (Loc,
Condition => Iterator_Filter (I_Spec),
Then_Statements => Stats));
end if;
-- for Element of Array loop
-- It requires an internally generated cursor to iterate over the array
pragma Assert (Of_Present (I_Spec));
Iterator := Make_Temporary (Loc, 'C');
-- Generate:
-- Element : Component_Type renames Array (Iterator);
-- Iterator is the index value, or a list of index values
-- in the case of a multidimensional array.
Ind_Comp :=
Make_Indexed_Component (Loc,
Prefix => New_Copy_Tree (Array_Node),
Expressions => New_List (New_Occurrence_Of (Iterator, Loc)));
-- Propagate the original node to the copy since the analysis of the
-- following object renaming declaration relies on the original node.
Set_Original_Node (Prefix (Ind_Comp), Original_Node (Array_Node));
Prepend_To (Stats,
Make_Object_Renaming_Declaration (Loc,
Defining_Identifier => Id,
Subtype_Mark =>
New_Occurrence_Of (Component_Type (Array_Typ), Loc),
Name => Ind_Comp));
-- Mark the loop variable as needing debug info, so that expansion
-- of the renaming will result in Materialize_Entity getting set via
-- Debug_Renaming_Declaration. (This setting is needed here because
-- the setting in Freeze_Entity comes after the expansion, which is
-- too late. ???)
Set_Debug_Info_Needed (Id);
-- Generate:
-- for Iterator in [reverse] Array'Range (Array_Dim) loop
-- Element : Component_Type renames Array (Iterator);
-- <original loop statements>
-- end loop;
-- If this is an iteration over a multidimensional array, the
-- innermost loop is over the last dimension in Ada, and over
-- the first dimension in Fortran.
if Convention (Array_Typ) = Convention_Fortran then
Dim1 := 1;
else
Dim1 := Array_Dim;
end if;
Core_Loop :=
Make_Loop_Statement (Sloc (N),
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification (Loc,
Defining_Identifier => Iterator,
Discrete_Subtype_Definition =>
Make_Attribute_Reference (Loc,
Prefix => New_Copy_Tree (Array_Node),
Attribute_Name => Name_Range,
Expressions => New_List (
Make_Integer_Literal (Loc, Dim1))),
Reverse_Present => Reverse_Present (I_Spec))),
Statements => Stats,
End_Label => Empty);
-- Processing for multidimensional array. The body of each loop is
-- a loop over a previous dimension, going in decreasing order in Ada
-- and in increasing order in Fortran.
if Array_Dim > 1 then
for Dim in 1 .. Array_Dim - 1 loop
if Convention (Array_Typ) = Convention_Fortran then
Dim1 := Dim + 1;
else
Dim1 := Array_Dim - Dim;
end if;
Iterator := Make_Temporary (Loc, 'C');
-- Generate the dimension loops starting from the innermost one
-- for Iterator in [reverse] Array'Range (Array_Dim - Dim) loop
-- <core loop>
-- end loop;
Core_Loop :=
Make_Loop_Statement (Sloc (N),
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification (Loc,
Defining_Identifier => Iterator,
Discrete_Subtype_Definition =>
Make_Attribute_Reference (Loc,
Prefix => New_Copy_Tree (Array_Node),
Attribute_Name => Name_Range,
Expressions => New_List (
Make_Integer_Literal (Loc, Dim1))),
Reverse_Present => Reverse_Present (I_Spec))),
Statements => New_List (Core_Loop),
End_Label => Empty);
-- Update the previously created object renaming declaration with
-- the new iterator, by adding the index of the next loop to the
-- indexed component, in the order that corresponds to the
-- convention.
if Convention (Array_Typ) = Convention_Fortran then
Append_To (Expressions (Ind_Comp),
New_Occurrence_Of (Iterator, Loc));
else
Prepend_To (Expressions (Ind_Comp),
New_Occurrence_Of (Iterator, Loc));
end if;
end loop;
end if;
-- Inherit the loop identifier from the original loop. This ensures that
-- the scope stack is consistent after the rewriting.
if Present (Identifier (N)) then
Set_Identifier (Core_Loop, Relocate_Node (Identifier (N)));
end if;
Rewrite (N, Core_Loop);
Analyze (N);
end Expand_Iterator_Loop_Over_Array;
-----------------------------------------
-- Expand_Iterator_Loop_Over_Container --
-----------------------------------------
-- For a 'for ... in' loop, such as:
-- for Cursor in Iterator_Function (...) loop
-- ...
-- end loop;
-- we generate:
-- Iter : Iterator_Type := Iterator_Function (...);
-- Cursor : Cursor_type := First (Iter); -- or Last for "reverse"
-- while Has_Element (Cursor) loop
-- ...
--
-- Cursor := Iter.Next (Cursor); -- or Prev for "reverse"
-- end loop;
-- For a 'for ... of' loop, such as:
-- for X of Container loop
-- ...
-- end loop;
-- the RM implies the generation of:
-- Iter : Iterator_Type := Container.Iterate; -- the Default_Iterator
-- Cursor : Cursor_Type := First (Iter); -- or Last for "reverse"
-- while Has_Element (Cursor) loop
-- declare
-- X : Element_Type renames Element (Cursor).Element.all;
-- -- or Constant_Element
-- begin
-- ...
-- end;
-- Cursor := Iter.Next (Cursor); -- or Prev for "reverse"
-- end loop;
-- In the general case, we do what the RM says. However, the operations
-- Element and Iter.Next are slow, which is bad inside a loop, because they
-- involve dispatching via interfaces, secondary stack manipulation,
-- Busy/Lock incr/decr, and adjust/finalization/at-end handling. So for the
-- predefined containers, we use an equivalent but optimized expansion.
-- In the optimized case, we make use of these:
-- procedure _Next (Position : in out Cursor); -- instead of Iter.Next
-- (or _Previous for reverse loops)
-- function Pseudo_Reference
-- (Container : aliased Vector'Class) return Reference_Control_Type;
-- type Element_Access is access all Element_Type;
-- function Get_Element_Access
-- (Position : Cursor) return not null Element_Access;
-- Next is declared in the visible part of the container packages.
-- The other three are added in the private part. (We're not supposed to
-- pollute the namespace for clients. The compiler has no trouble breaking
-- privacy to call things in the private part of an instance.)
-- Note that Next and Previous are renamed as _Next and _Previous with
-- leading underscores. Leading underscores are illegal in Ada, but we
-- allow them in the run-time library. This allows us to avoid polluting
-- the user-visible namespaces.
-- Source:
-- for X of My_Vector loop
-- X.Count := X.Count + 1;
-- ...
-- end loop;
-- The compiler will generate:
-- Iter : Reversible_Iterator'Class := Iterate (My_Vector);
-- -- Reversible_Iterator is an interface. Iterate is the
-- -- Default_Iterator aspect of Vector. This increments Lock,
-- -- disallowing tampering with cursors. Unfortunately, it does not
-- -- increment Busy. The result of Iterate is Limited_Controlled;
-- -- finalization will decrement Lock. This is a build-in-place
-- -- dispatching call to Iterate.
-- Cur : Cursor := First (Iter); -- or Last
-- -- Dispatching call via interface.
-- Control : Reference_Control_Type := Pseudo_Reference (My_Vector);
-- -- Pseudo_Reference increments Busy, to detect tampering with
-- -- elements, as required by RM. Also redundantly increment
-- -- Lock. Finalization of Control will decrement both Busy and
-- -- Lock. Pseudo_Reference returns a record containing a pointer to
-- -- My_Vector, used by Finalize.
-- --
-- -- Control is not used below, except to finalize it -- it's purely
-- -- an RAII thing. This is needed because we are eliminating the
-- -- call to Reference within the loop.
-- while Has_Element (Cur) loop
-- declare
-- X : My_Element renames Get_Element_Access (Cur).all;
-- -- Get_Element_Access returns a pointer to the element
-- -- designated by Cur. No dispatching here, and no horsing
-- -- around with access discriminants. This is instead of the
-- -- existing
-- --
-- -- X : My_Element renames Reference (Cur).Element.all;
-- --
-- -- which creates a controlled object.
-- begin
-- -- Any attempt to tamper with My_Vector here in the loop
-- -- will correctly raise Program_Error, because of the
-- -- Control.
--
-- X.Count := X.Count + 1;
-- ...
--
-- _Next (Cur); -- or _Previous
-- -- This is instead of "Cur := Next (Iter, Cur);"
-- end;
-- -- No finalization here
-- end loop;
-- Finalize Iter and Control here, decrementing Lock twice and Busy
-- once.
-- This optimization makes "for ... of" loops over 30 times faster in cases
-- measured.
procedure Expand_Iterator_Loop_Over_Container
(N : Node_Id;
I_Spec : Node_Id;
Container : Node_Id;
Container_Typ : Entity_Id)
is
Id : constant Entity_Id := Defining_Identifier (I_Spec);
Elem_Typ : constant Entity_Id := Etype (Id);
Id_Kind : constant Entity_Kind := Ekind (Id);
Loc : constant Source_Ptr := Sloc (N);
Stats : List_Id := Statements (N);
-- Maybe wrapped in a conditional if a filter is present
Cursor : Entity_Id;
Decl : Node_Id;
Iter_Type : Entity_Id;
Iterator : Entity_Id;
Name_Init : Name_Id;
Name_Step : Name_Id;
Name_Fast_Step : Name_Id;
New_Loop : Node_Id;
Fast_Element_Access_Op : Entity_Id := Empty;
Fast_Step_Op : Entity_Id := Empty;
-- Only for optimized version of "for ... of"
Iter_Pack : Entity_Id;
-- The package in which the iterator interface is instantiated. This is
-- typically an instance within the container package.
begin
if Present (Iterator_Filter (I_Spec)) then
pragma Assert (Ada_Version >= Ada_2022);
Stats := New_List (Make_If_Statement (Loc,
Condition => Iterator_Filter (I_Spec),
Then_Statements => Stats));
end if;
-- Determine the advancement and initialization steps for the cursor.
-- Analysis of the expanded loop will verify that the container has a
-- reverse iterator.
if Reverse_Present (I_Spec) then
Name_Init := Name_Last;
Name_Step := Name_Previous;
Name_Fast_Step := Name_uPrevious;
else
Name_Init := Name_First;
Name_Step := Name_Next;
Name_Fast_Step := Name_uNext;
end if;
-- The type of the iterator is the return type of the Iterate function
-- used. For the "of" form this is the default iterator for the type,
-- otherwise it is the type of the explicit function used in the
-- iterator specification. The most common case will be an Iterate
-- function in the container package.
-- The Iterator type is declared in an instance within the container
-- package itself, for example:
-- package Vector_Iterator_Interfaces is new
-- Ada.Iterator_Interfaces (Cursor, Has_Element);
if Of_Present (I_Spec) then
Handle_Of : declare
Container_Arg : Node_Id;
function Get_Default_Iterator
(T : Entity_Id) return Entity_Id;
-- Return the default iterator for a specific type. If the type is
-- derived, we return the inherited or overridden one if
-- appropriate.
--------------------------
-- Get_Default_Iterator --
--------------------------
function Get_Default_Iterator
(T : Entity_Id) return Entity_Id
is
Iter : constant Entity_Id :=
Entity (Find_Value_Of_Aspect (T, Aspect_Default_Iterator));
Prim : Elmt_Id;
Op : Entity_Id;
begin
Container_Arg := New_Copy_Tree (Container);
-- A previous version of GNAT allowed indexing aspects to be
-- redefined on derived container types, while the default
-- iterator was inherited from the parent type. This
-- nonstandard extension is preserved for use by the
-- modeling project under debug flag -gnatd.X.
if Debug_Flag_Dot_XX then
if Base_Type (Etype (Container)) /=
Base_Type (Etype (First_Formal (Iter)))
then
Container_Arg :=
Make_Type_Conversion (Loc,
Subtype_Mark =>
New_Occurrence_Of
(Etype (First_Formal (Iter)), Loc),
Expression => Container_Arg);
end if;
return Iter;
elsif Is_Derived_Type (T) then
-- The default iterator must be a primitive operation of the
-- type, at the same dispatch slot position. The DT position
-- may not be established if type is not frozen yet.
Prim := First_Elmt (Primitive_Operations (T));
while Present (Prim) loop
Op := Node (Prim);
if Alias (Op) = Iter
or else
(Chars (Op) = Chars (Iter)
and then Present (DTC_Entity (Op))
and then DT_Position (Op) = DT_Position (Iter))
then
return Op;
end if;
Next_Elmt (Prim);
end loop;
-- If we didn't find it, then our parent type is not
-- iterable, so we return the Default_Iterator aspect of
-- this type.
return Iter;
-- Otherwise not a derived type
else
return Iter;
end if;
end Get_Default_Iterator;
-- Local variables
Default_Iter : Entity_Id;
Ent : Entity_Id;
Cont_Type_Pack : Entity_Id;
-- The package in which the container type is declared
Reference_Control_Type : Entity_Id := Empty;
Pseudo_Reference : Entity_Id := Empty;
-- Start of processing for Handle_Of
begin
if Is_Class_Wide_Type (Container_Typ) then
Default_Iter :=
Get_Default_Iterator (Etype (Base_Type (Container_Typ)));
else
Default_Iter := Get_Default_Iterator (Etype (Container));
end if;
Cursor := Make_Temporary (Loc, 'C');
-- For a container element iterator, the iterator type is obtained
-- from the corresponding aspect, whose return type is descended
-- from the corresponding interface type in some instance of
-- Ada.Iterator_Interfaces. The actuals of that instantiation
-- are Cursor and Has_Element.
Iter_Type := Etype (Default_Iter);
-- If the container type is a derived type, the cursor type is
-- found in the package of the ultimate ancestor type.
if Is_Derived_Type (Container_Typ) then
Cont_Type_Pack := Scope (Root_Type (Container_Typ));
else
Cont_Type_Pack := Scope (Container_Typ);
end if;
-- Find declarations needed for "for ... of" optimization.
-- These declarations come from GNAT sources or sources
-- derived from them. User code may include additional
-- overloadings with similar names, and we need to perforn
-- some reasonable resolution to find the needed primitives.
-- Note that we use _Next or _Previous to avoid picking up
-- some arbitrary user-defined Next or Previous.
Ent := First_Entity (Cont_Type_Pack);
while Present (Ent) loop
-- Ignore subprogram bodies
if Ekind (Ent) = E_Subprogram_Body then
null;
-- Get_Element_Access function with one parameter called
-- Position.
elsif Chars (Ent) = Name_Get_Element_Access
and then Ekind (Ent) = E_Function
and then Present (First_Formal (Ent))
and then Chars (First_Formal (Ent)) = Name_Position
and then No (Next_Formal (First_Formal (Ent)))
then
pragma Assert (No (Fast_Element_Access_Op));
Fast_Element_Access_Op := Ent;
-- Next or Prev procedure with one parameter called
-- Position.
elsif Chars (Ent) = Name_Fast_Step then
pragma Assert (No (Fast_Step_Op));
Fast_Step_Op := Ent;
elsif Chars (Ent) = Name_Reference_Control_Type then
pragma Assert (No (Reference_Control_Type));
Reference_Control_Type := Ent;
elsif Chars (Ent) = Name_Pseudo_Reference then
pragma Assert (No (Pseudo_Reference));
Pseudo_Reference := Ent;
end if;
Next_Entity (Ent);
end loop;
if Present (Reference_Control_Type)
and then Present (Pseudo_Reference)
then
Insert_Action (N,
Make_Object_Declaration (Loc,
Defining_Identifier => Make_Temporary (Loc, 'D'),
Object_Definition =>
New_Occurrence_Of (Reference_Control_Type, Loc),
Expression =>
Make_Function_Call (Loc,
Name =>
New_Occurrence_Of (Pseudo_Reference, Loc),
Parameter_Associations =>
New_List (New_Copy_Tree (Container_Arg)))));
end if;
-- Rewrite domain of iteration as a call to the default iterator
-- for the container type. The formal may be an access parameter
-- in which case we must build a reference to the container.
declare
Arg : Node_Id;
begin
if Is_Access_Type (Etype (First_Entity (Default_Iter))) then
Arg :=
Make_Attribute_Reference (Loc,
Prefix => Container_Arg,
Attribute_Name => Name_Unrestricted_Access);
else
Arg := Container_Arg;
end if;
Rewrite (Name (I_Spec),
Make_Function_Call (Loc,
Name =>
New_Occurrence_Of (Default_Iter, Loc),
Parameter_Associations => New_List (Arg)));
end;
Analyze_And_Resolve (Name (I_Spec));
-- The desired instantiation is the scope of an iterator interface
-- type that is an ancestor of the iterator type.
Iter_Pack := Scope (Iterator_Interface_Ancestor (Iter_Type));
-- Find cursor type in proper iterator package, which is an
-- instantiation of Iterator_Interfaces.
Ent := First_Entity (Iter_Pack);
while Present (Ent) loop
if Chars (Ent) = Name_Cursor then
Set_Etype (Cursor, Etype (Ent));
exit;
end if;
Next_Entity (Ent);
end loop;
if Present (Fast_Element_Access_Op) then
Decl :=
Make_Object_Renaming_Declaration (Loc,
Defining_Identifier => Id,
Subtype_Mark =>
New_Occurrence_Of (Elem_Typ, Loc),
Name =>
Make_Explicit_Dereference (Loc,
Prefix =>
Make_Function_Call (Loc,
Name =>
New_Occurrence_Of (Fast_Element_Access_Op, Loc),
Parameter_Associations =>
New_List (New_Occurrence_Of (Cursor, Loc)))));
else
Decl :=
Make_Object_Renaming_Declaration (Loc,
Defining_Identifier => Id,
Subtype_Mark =>
New_Occurrence_Of (Elem_Typ, Loc),
Name =>
Make_Indexed_Component (Loc,
Prefix => Relocate_Node (Container_Arg),
Expressions =>
New_List (New_Occurrence_Of (Cursor, Loc))));
end if;
-- The defining identifier in the iterator is user-visible and
-- must be visible in the debugger.
Set_Debug_Info_Needed (Id);
-- If the container does not have a variable indexing aspect,
-- the element is a constant in the loop. The container itself
-- may be constant, in which case the element is a constant as
-- well. The container has been rewritten as a call to Iterate,
-- so examine original node.
if No (Find_Value_Of_Aspect
(Container_Typ, Aspect_Variable_Indexing))
or else not Is_Variable (Original_Node (Container))
then
Mutate_Ekind (Id, E_Constant);
end if;
Prepend_To (Stats, Decl);
end Handle_Of;
-- X in Iterate (S) : type of iterator is type of explicitly given
-- Iterate function, and the loop variable is the cursor. It will be
-- assigned in the loop and must be a variable.
else
Iter_Type := Etype (Name (I_Spec));
-- The instantiation in which to locate the Has_Element function
-- is the scope containing an iterator interface type that is
-- an ancestor of the iterator type.
Iter_Pack := Scope (Iterator_Interface_Ancestor (Iter_Type));
Cursor := Id;
end if;
Iterator := Make_Temporary (Loc, 'I');
-- For both iterator forms, add a call to the step operation to advance
-- the cursor. Generate:
-- Cursor := Iterator.Next (Cursor);
-- or else
-- Cursor := Next (Cursor);
if Present (Fast_Element_Access_Op) and then Present (Fast_Step_Op) then
declare
Curs_Name : constant Node_Id := New_Occurrence_Of (Cursor, Loc);
Step_Call : Node_Id;
begin
Step_Call :=
Make_Procedure_Call_Statement (Loc,
Name =>
New_Occurrence_Of (Fast_Step_Op, Loc),
Parameter_Associations => New_List (Curs_Name));
Append_To (Stats, Step_Call);
Set_Assignment_OK (Curs_Name);
end;
else
declare
Rhs : Node_Id;
begin
Rhs :=
Make_Function_Call (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => New_Occurrence_Of (Iterator, Loc),
Selector_Name => Make_Identifier (Loc, Name_Step)),
Parameter_Associations => New_List (
New_Occurrence_Of (Cursor, Loc)));
Append_To (Stats,
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Cursor, Loc),
Expression => Rhs));
Set_Assignment_OK (Name (Last (Stats)));
end;
end if;
-- Generate:
-- while Has_Element (Cursor) loop
-- <Stats>
-- end loop;
-- Has_Element is the second actual in the iterator package
New_Loop :=
Make_Loop_Statement (Loc,
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Condition =>
Make_Function_Call (Loc,
Name =>
New_Occurrence_Of
(Next_Entity (First_Entity (Iter_Pack)), Loc),
Parameter_Associations => New_List (
New_Occurrence_Of (Cursor, Loc)))),
Statements => Stats,
End_Label => Empty);
-- If present, preserve identifier of loop, which can be used in an exit
-- statement in the body.
if Present (Identifier (N)) then
Set_Identifier (New_Loop, Relocate_Node (Identifier (N)));
end if;
-- Create the declarations for Iterator and cursor and insert them
-- before the source loop. Given that the domain of iteration is already
-- an entity, the iterator is just a renaming of that entity. Possible
-- optimization ???
Insert_Action (N,
Make_Object_Renaming_Declaration (Loc,
Defining_Identifier => Iterator,
Subtype_Mark => New_Occurrence_Of (Iter_Type, Loc),
Name => Relocate_Node (Name (I_Spec))));
-- Create declaration for cursor
declare
Cursor_Decl : constant Node_Id :=
Make_Object_Declaration (Loc,
Defining_Identifier => Cursor,
Object_Definition =>
New_Occurrence_Of (Etype (Cursor), Loc),
Expression =>
Make_Selected_Component (Loc,
Prefix =>
New_Occurrence_Of (Iterator, Loc),
Selector_Name =>
Make_Identifier (Loc, Name_Init)));
begin
-- The cursor is only modified in expanded code, so it appears
-- as unassigned to the warning machinery. We must suppress this
-- spurious warning explicitly. The cursor's kind is that of the
-- original loop parameter (it is a constant if the domain of
-- iteration is constant).
Set_Warnings_Off (Cursor);
Set_Assignment_OK (Cursor_Decl);
Insert_Action (N, Cursor_Decl);
Reinit_Field_To_Zero (Cursor, F_Has_Initial_Value,
Old_Ekind => (E_Variable => True, others => False));
Reinit_Field_To_Zero (Cursor, F_Is_Elaboration_Checks_OK_Id);
Reinit_Field_To_Zero (Cursor, F_Is_Elaboration_Warnings_OK_Id);
Reinit_Field_To_Zero (Cursor, F_SPARK_Pragma);
Reinit_Field_To_Zero (Cursor, F_SPARK_Pragma_Inherited);
Mutate_Ekind (Cursor, Id_Kind);
end;
Rewrite (N, New_Loop);
Analyze (N);
end Expand_Iterator_Loop_Over_Container;
-----------------------------
-- Expand_N_Loop_Statement --
-----------------------------
-- 1. Remove null loop entirely
-- 2. Deal with while condition for C/Fortran boolean
-- 3. Deal with loops with a non-standard enumeration type range
-- 4. Deal with while loops where Condition_Actions is set
-- 5. Deal with loops over predicated subtypes
-- 6. Deal with loops with iterators over arrays and containers
procedure Expand_N_Loop_Statement (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Scheme : constant Node_Id := Iteration_Scheme (N);
Stmt : Node_Id;
begin
-- Delete null loop
if Is_Null_Loop (N) then
Rewrite (N, Make_Null_Statement (Loc));
return;
end if;
-- Deal with condition for C/Fortran Boolean
if Present (Scheme) then
Adjust_Condition (Condition (Scheme));
end if;
-- Nothing more to do for plain loop with no iteration scheme
if No (Scheme) then
null;
-- Case of for loop (Loop_Parameter_Specification present)
-- Note: we do not have to worry about validity checking of the for loop
-- range bounds here, since they were frozen with constant declarations
-- and it is during that process that the validity checking is done.
elsif Present (Loop_Parameter_Specification (Scheme)) then
declare
LPS : constant Node_Id :=
Loop_Parameter_Specification (Scheme);
Loop_Id : constant Entity_Id := Defining_Identifier (LPS);
Ltype : constant Entity_Id := Etype (Loop_Id);
Btype : constant Entity_Id := Base_Type (Ltype);
Stats : constant List_Id := Statements (N);
Expr : Node_Id;
Decls : List_Id;
New_Id : Entity_Id;
begin
-- If Discrete_Subtype_Definition has been rewritten as an
-- N_Raise_xxx_Error, rewrite the whole loop as a raise node to
-- avoid confusing the code generator down the line.
if Nkind (Discrete_Subtype_Definition (LPS)) in N_Raise_xxx_Error
then
Rewrite (N, Discrete_Subtype_Definition (LPS));
return;
end if;
if Present (Iterator_Filter (LPS)) then
pragma Assert (Ada_Version >= Ada_2022);
Set_Statements (N,
New_List (Make_If_Statement (Loc,
Condition => Iterator_Filter (LPS),
Then_Statements => Stats)));
Analyze_List (Statements (N));
end if;
-- Deal with loop over predicates
if Is_Discrete_Type (Ltype)
and then Present (Predicate_Function (Ltype))
then
Expand_Predicated_Loop (N);
-- Handle the case where we have a for loop with the range type
-- being an enumeration type with non-standard representation.
-- In this case we expand:
-- for x in [reverse] a .. b loop
-- ...
-- end loop;
-- to
-- for xP in [reverse] integer
-- range etype'Pos (a) .. etype'Pos (b)
-- loop
-- declare
-- x : constant etype := Pos_To_Rep (xP);
-- begin
-- ...
-- end;
-- end loop;
elsif Is_Enumeration_Type (Btype)
and then Present (Enum_Pos_To_Rep (Btype))
then
New_Id :=
Make_Defining_Identifier (Loc,
Chars => New_External_Name (Chars (Loop_Id), 'P'));
-- If the type has a contiguous representation, successive
-- values can be generated as offsets from the first literal.
if Has_Contiguous_Rep (Btype) then
Expr :=
Unchecked_Convert_To (Btype,
Make_Op_Add (Loc,
Left_Opnd =>
Make_Integer_Literal (Loc,
Enumeration_Rep (First_Literal (Btype))),
Right_Opnd => New_Occurrence_Of (New_Id, Loc)));
else
-- Use the constructed array Enum_Pos_To_Rep
Expr :=
Make_Indexed_Component (Loc,
Prefix =>
New_Occurrence_Of (Enum_Pos_To_Rep (Btype), Loc),
Expressions =>
New_List (New_Occurrence_Of (New_Id, Loc)));
end if;
-- Build declaration for loop identifier
Decls :=
New_List (
Make_Object_Declaration (Loc,
Defining_Identifier => Loop_Id,
Constant_Present => True,
Object_Definition => New_Occurrence_Of (Ltype, Loc),
Expression => Expr));
Rewrite (N,
Make_Loop_Statement (Loc,
Identifier => Identifier (N),
Iteration_Scheme =>
Make_Iteration_Scheme (Loc,
Loop_Parameter_Specification =>
Make_Loop_Parameter_Specification (Loc,
Defining_Identifier => New_Id,
Reverse_Present => Reverse_Present (LPS),
Discrete_Subtype_Definition =>
Make_Subtype_Indication (Loc,
Subtype_Mark =>
New_Occurrence_Of (Standard_Natural, Loc),
Constraint =>
Make_Range_Constraint (Loc,
Range_Expression =>
Make_Range (Loc,
Low_Bound =>
Make_Attribute_Reference (Loc,
Prefix =>
New_Occurrence_Of (Btype, Loc),
Attribute_Name => Name_Pos,
Expressions => New_List (
Relocate_Node
(Type_Low_Bound (Ltype)))),
High_Bound =>
Make_Attribute_Reference (Loc,
Prefix =>
New_Occurrence_Of (Btype, Loc),
Attribute_Name => Name_Pos,
Expressions => New_List (
Relocate_Node
(Type_High_Bound
(Ltype))))))))),
Statements => New_List (
Make_Block_Statement (Loc,
Declarations => Decls,
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => Stats))),
End_Label => End_Label (N)));
-- The loop parameter's entity must be removed from the loop
-- scope's entity list and rendered invisible, since it will
-- now be located in the new block scope. Any other entities
-- already associated with the loop scope, such as the loop
-- parameter's subtype, will remain there.
-- In an element loop, the loop will contain a declaration for
-- a cursor variable; otherwise the loop id is the first entity
-- in the scope constructed for the loop.
if Comes_From_Source (Loop_Id) then
pragma Assert (First_Entity (Scope (Loop_Id)) = Loop_Id);
null;
end if;
Set_First_Entity (Scope (Loop_Id), Next_Entity (Loop_Id));
Remove_Homonym (Loop_Id);
if Last_Entity (Scope (Loop_Id)) = Loop_Id then
Set_Last_Entity (Scope (Loop_Id), Empty);
end if;
Analyze (N);
-- Nothing to do with other cases of for loops
else
null;
end if;
end;
-- Second case, if we have a while loop with Condition_Actions set, then
-- we change it into a plain loop:
-- while C loop
-- ...
-- end loop;
-- changed to:
-- loop
-- <<condition actions>>
-- exit when not C;
-- ...
-- end loop
elsif Present (Scheme)
and then Present (Condition_Actions (Scheme))
and then Present (Condition (Scheme))
then
declare
ES : Node_Id;
begin
ES :=
Make_Exit_Statement (Sloc (Condition (Scheme)),
Condition =>
Make_Op_Not (Sloc (Condition (Scheme)),
Right_Opnd => Condition (Scheme)));
Prepend (ES, Statements (N));
Insert_List_Before (ES, Condition_Actions (Scheme));
-- This is not an implicit loop, since it is generated in response
-- to the loop statement being processed. If this is itself
-- implicit, the restriction has already been checked. If not,
-- it is an explicit loop.
Rewrite (N,
Make_Loop_Statement (Sloc (N),
Identifier => Identifier (N),
Statements => Statements (N),
End_Label => End_Label (N)));
Analyze (N);
end;
-- Here to deal with iterator case
elsif Present (Scheme)
and then Present (Iterator_Specification (Scheme))
then
Expand_Iterator_Loop (N);
-- An iterator loop may generate renaming declarations for elements
-- that require debug information. This is the case in particular
-- with element iterators, where debug information must be generated
-- for the temporary that holds the element value. These temporaries
-- are created within a transient block whose local declarations are
-- transferred to the loop, which now has nontrivial local objects.
if Nkind (N) = N_Loop_Statement
and then Present (Identifier (N))
then
Qualify_Entity_Names (N);
end if;
end if;
-- When the iteration scheme mentions attribute 'Loop_Entry, the loop
-- is transformed into a conditional block where the original loop is
-- the sole statement. Inspect the statements of the nested loop for
-- controlled objects.
Stmt := N;
if Subject_To_Loop_Entry_Attributes (Stmt) then
Stmt := Find_Loop_In_Conditional_Block (Stmt);
end if;
Process_Statements_For_Controlled_Objects (Stmt);
end Expand_N_Loop_Statement;
----------------------------
-- Expand_Predicated_Loop --
----------------------------
-- Note: the expander can handle generation of loops over predicated
-- subtypes for both the dynamic and static cases. Depending on what
-- we decide is allowed in Ada 2012 mode and/or extensions allowed
-- mode, the semantic analyzer may disallow one or both forms.
procedure Expand_Predicated_Loop (N : Node_Id) is
Orig_Loop_Id : Node_Id := Empty;
Loc : constant Source_Ptr := Sloc (N);
Isc : constant Node_Id := Iteration_Scheme (N);
LPS : constant Node_Id := Loop_Parameter_Specification (Isc);
Loop_Id : constant Entity_Id := Defining_Identifier (LPS);
Ltype : constant Entity_Id := Etype (Loop_Id);
Stat : constant List_Id := Static_Discrete_Predicate (Ltype);
Stmts : constant List_Id := Statements (N);
begin
-- Case of iteration over non-static predicate, should not be possible
-- since this is not allowed by the semantics and should have been
-- caught during analysis of the loop statement.
if No (Stat) then
raise Program_Error;
-- If the predicate list is empty, that corresponds to a predicate of
-- False, in which case the loop won't run at all, and we rewrite the
-- entire loop as a null statement.
elsif Is_Empty_List (Stat) then
Rewrite (N, Make_Null_Statement (Loc));
Analyze (N);
-- For expansion over a static predicate we generate the following
-- declare
-- J : Ltype := min-val;
-- begin
-- loop
-- body
-- case J is
-- when endpoint => J := startpoint;
-- when endpoint => J := startpoint;
-- ...
-- when max-val => exit;
-- when others => J := Lval'Succ (J);
-- end case;
-- end loop;
-- end;
-- with min-val replaced by max-val and Succ replaced by Pred if the
-- loop parameter specification carries a Reverse indicator.
-- To make this a little clearer, let's take a specific example:
-- type Int is range 1 .. 10;
-- subtype StaticP is Int with
-- predicate => StaticP in 3 | 10 | 5 .. 7;
-- ...
-- for L in StaticP loop
-- Put_Line ("static:" & J'Img);
-- end loop;
-- In this case, the loop is transformed into
-- begin
-- J : L := 3;
-- loop
-- body
-- case J is
-- when 3 => J := 5;
-- when 7 => J := 10;
-- when 10 => exit;
-- when others => J := L'Succ (J);
-- end case;
-- end loop;
-- end;
-- In addition, if the loop specification is given by a subtype
-- indication that constrains a predicated type, the bounds of
-- iteration are given by those of the subtype indication.
else
Static_Predicate : declare
S : Node_Id;
D : Node_Id;
P : Node_Id;
Alts : List_Id;
Cstm : Node_Id;
-- If the domain is an itype, note the bounds of its range.
L_Hi : Node_Id := Empty;
L_Lo : Node_Id := Empty;
function Lo_Val (N : Node_Id) return Node_Id;
-- Given static expression or static range, returns an identifier
-- whose value is the low bound of the expression value or range.
function Hi_Val (N : Node_Id) return Node_Id;
-- Given static expression or static range, returns an identifier
-- whose value is the high bound of the expression value or range.
------------
-- Hi_Val --
------------
function Hi_Val (N : Node_Id) return Node_Id is
begin
if Is_OK_Static_Expression (N) then
return New_Copy (N);
else
pragma Assert (Nkind (N) = N_Range);
return New_Copy (High_Bound (N));
end if;
end Hi_Val;
------------
-- Lo_Val --
------------
function Lo_Val (N : Node_Id) return Node_Id is
begin
if Is_OK_Static_Expression (N) then
return New_Copy (N);
else
pragma Assert (Nkind (N) = N_Range);
return New_Copy (Low_Bound (N));
end if;
end Lo_Val;
-- Start of processing for Static_Predicate
begin
-- Convert loop identifier to normal variable and reanalyze it so
-- that this conversion works. We have to use the same defining
-- identifier, since there may be references in the loop body.
Set_Analyzed (Loop_Id, False);
Mutate_Ekind (Loop_Id, E_Variable);
-- In most loops the loop variable is assigned in various
-- alternatives in the body. However, in the rare case when
-- the range specifies a single element, the loop variable
-- may trigger a spurious warning that is could be constant.
-- This warning might as well be suppressed.
Set_Warnings_Off (Loop_Id);
if Is_Itype (Ltype) then
L_Hi := High_Bound (Scalar_Range (Ltype));
L_Lo := Low_Bound (Scalar_Range (Ltype));
end if;
-- Loop to create branches of case statement
Alts := New_List;
if Reverse_Present (LPS) then
-- Initial value is largest value in predicate.
if Is_Itype (Ltype) then
D :=
Make_Object_Declaration (Loc,
Defining_Identifier => Loop_Id,
Object_Definition => New_Occurrence_Of (Ltype, Loc),
Expression => L_Hi);
else
D :=
Make_Object_Declaration (Loc,
Defining_Identifier => Loop_Id,
Object_Definition => New_Occurrence_Of (Ltype, Loc),
Expression => Hi_Val (Last (Stat)));
end if;
P := Last (Stat);
while Present (P) loop
if No (Prev (P)) then
S := Make_Exit_Statement (Loc);
else
S :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Loop_Id, Loc),
Expression => Hi_Val (Prev (P)));
Set_Suppress_Assignment_Checks (S);
end if;
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Statements => New_List (S),
Discrete_Choices => New_List (Lo_Val (P))));
Prev (P);
end loop;
if Is_Itype (Ltype)
and then Is_OK_Static_Expression (L_Lo)
and then
Expr_Value (L_Lo) /= Expr_Value (Lo_Val (First (Stat)))
then
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Statements => New_List (Make_Exit_Statement (Loc)),
Discrete_Choices => New_List (L_Lo)));
end if;
else
-- Initial value is smallest value in predicate
if Is_Itype (Ltype) then
D :=
Make_Object_Declaration (Loc,
Defining_Identifier => Loop_Id,
Object_Definition => New_Occurrence_Of (Ltype, Loc),
Expression => L_Lo);
else
D :=
Make_Object_Declaration (Loc,
Defining_Identifier => Loop_Id,
Object_Definition => New_Occurrence_Of (Ltype, Loc),
Expression => Lo_Val (First (Stat)));
end if;
P := First (Stat);
while Present (P) loop
if No (Next (P)) then
S := Make_Exit_Statement (Loc);
else
S :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Loop_Id, Loc),
Expression => Lo_Val (Next (P)));
Set_Suppress_Assignment_Checks (S);
end if;
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Statements => New_List (S),
Discrete_Choices => New_List (Hi_Val (P))));
Next (P);
end loop;
if Is_Itype (Ltype)
and then Is_OK_Static_Expression (L_Hi)
and then
Expr_Value (L_Hi) /= Expr_Value (Lo_Val (Last (Stat)))
then
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Statements => New_List (Make_Exit_Statement (Loc)),
Discrete_Choices => New_List (L_Hi)));
end if;
end if;
-- Add others choice
declare
Name_Next : Name_Id;
begin
if Reverse_Present (LPS) then
Name_Next := Name_Pred;
else
Name_Next := Name_Succ;
end if;
S :=
Make_Assignment_Statement (Loc,
Name => New_Occurrence_Of (Loop_Id, Loc),
Expression =>
Make_Attribute_Reference (Loc,
Prefix => New_Occurrence_Of (Ltype, Loc),
Attribute_Name => Name_Next,
Expressions => New_List (
New_Occurrence_Of (Loop_Id, Loc))));
Set_Suppress_Assignment_Checks (S);
end;
Append_To (Alts,
Make_Case_Statement_Alternative (Loc,
Discrete_Choices => New_List (Make_Others_Choice (Loc)),
Statements => New_List (S)));
-- Construct case statement and append to body statements
Cstm :=
Make_Case_Statement (Loc,
Expression => New_Occurrence_Of (Loop_Id, Loc),
Alternatives => Alts);
Append_To (Stmts, Cstm);
-- Rewrite the loop preserving the loop identifier in case there
-- are exit statements referencing it.
if Present (Identifier (N)) then
Orig_Loop_Id := New_Occurrence_Of
(Entity (Identifier (N)), Loc);
end if;
Set_Suppress_Assignment_Checks (D);
Rewrite (N,
Make_Block_Statement (Loc,
Declarations => New_List (D),
Handled_Statement_Sequence =>
Make_Handled_Sequence_Of_Statements (Loc,
Statements => New_List (
Make_Loop_Statement (Loc,
Statements => Stmts,
Identifier => Orig_Loop_Id,
End_Label => Empty)))));
Analyze (N);
end Static_Predicate;
end if;
end Expand_Predicated_Loop;
------------------------------
-- Make_Tag_Ctrl_Assignment --
------------------------------
function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id is
Asn : constant Node_Id := Relocate_Node (N);
L : constant Node_Id := Name (N);
Loc : constant Source_Ptr := Sloc (N);
Res : constant List_Id := New_List;
T : constant Entity_Id := Underlying_Type (Etype (L));
Adj_Act : constant Boolean := Needs_Finalization (T)
and then not No_Ctrl_Actions (N);
Comp_Asn : constant Boolean := Is_Fully_Repped_Tagged_Type (T);
Ctrl_Act : constant Boolean := Needs_Finalization (T)
and then not No_Ctrl_Actions (N)
and then not No_Finalize_Actions (N);
Save_Tag : constant Boolean := Is_Tagged_Type (T)
and then not Comp_Asn
and then not No_Ctrl_Actions (N)
and then not No_Finalize_Actions (N)
and then Tagged_Type_Expansion;
Set_Tag : constant Boolean := Is_Tagged_Type (T)
and then not Comp_Asn
and then not No_Ctrl_Actions (N)
and then Tagged_Type_Expansion;
Adj_Call : Node_Id;
Fin_Call : Node_Id;
Tag_Id : Entity_Id;
begin
-- Finalize the target of the assignment when controlled
-- We have two exceptions here:
-- 1. If we are in an init proc or within an aggregate, since it is an
-- initialization more than an assignment.
-- 2. If the left-hand side is a temporary that was not initialized
-- (or the parent part of a temporary since it is the case in
-- extension aggregates). Such a temporary does not come from
-- source. We must examine the original node for the prefix, because
-- it may be a component of an entry formal, in which case it has
-- been rewritten and does not appear to come from source either.
-- Case of init proc or aggregate
if not Ctrl_Act then
null;
-- The left-hand side is an uninitialized temporary object
elsif Nkind (L) = N_Type_Conversion
and then Is_Entity_Name (Expression (L))
and then Nkind (Parent (Entity (Expression (L)))) =
N_Object_Declaration
and then No_Initialization (Parent (Entity (Expression (L))))
then
null;
else
Fin_Call :=
Make_Final_Call
(Obj_Ref => Duplicate_Subexpr_No_Checks (L),
Typ => Etype (L));
if Present (Fin_Call) then
Append_To (Res, Fin_Call);
end if;
end if;
-- Save the Tag in a local variable Tag_Id
if Save_Tag then
Tag_Id := Make_Temporary (Loc, 'A');
Append_To (Res,
Make_Object_Declaration (Loc,
Defining_Identifier => Tag_Id,
Object_Definition => New_Occurrence_Of (RTE (RE_Tag), Loc),
Expression =>
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr_No_Checks (L),
Selector_Name =>
New_Occurrence_Of (First_Tag_Component (T), Loc))));
-- Otherwise Tag_Id is not used
else
Tag_Id := Empty;
end if;
-- If the tagged type has a full rep clause, expand the assignment into
-- component-wise assignments. Mark the node as unanalyzed in order to
-- generate the proper code and propagate this scenario by setting a
-- flag to avoid infinite recursion.
if Comp_Asn then
Set_Analyzed (Asn, False);
Set_Componentwise_Assignment (Asn, True);
end if;
Append_To (Res, Asn);
-- Restore the tag
if Save_Tag then
Append_To (Res,
Make_Assignment_Statement (Loc,
Name =>
Make_Selected_Component (Loc,
Prefix => Duplicate_Subexpr_No_Checks (L),
Selector_Name =>
New_Occurrence_Of (First_Tag_Component (T), Loc)),
Expression => New_Occurrence_Of (Tag_Id, Loc)));
-- Or else just initialize it
elsif Set_Tag then
Append_To (Res,
Make_Tag_Assignment_From_Type
(Loc, Duplicate_Subexpr_No_Checks (L), T));
end if;
-- Adjust the target after the assignment when controlled (not in the
-- init proc since it is an initialization more than an assignment).
if Ctrl_Act or else Adj_Act then
Adj_Call :=
Make_Adjust_Call
(Obj_Ref => Duplicate_Subexpr_Move_Checks (L),
Typ => Etype (L));
if Present (Adj_Call) then
Append_To (Res, Adj_Call);
end if;
end if;
return Res;
exception
-- Could use comment here ???
when RE_Not_Available =>
return Empty_List;
end Make_Tag_Ctrl_Assignment;
end Exp_Ch5;
|