summaryrefslogtreecommitdiff
path: root/gnu/usr.bin/perl/gv.c
blob: ce6847842c76d510c70fad27e8b70a8df3e67f84 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
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
/*    gv.c
 *
 *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
 *    2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

/*
 *   'Mercy!' cried Gandalf.  'If the giving of information is to be the cure
 * of your inquisitiveness, I shall spend all the rest of my days in answering
 * you.  What more do you want to know?'
 *   'The names of all the stars, and of all living things, and the whole
 * history of Middle-earth and Over-heaven and of the Sundering Seas,'
 * laughed Pippin.
 *
 *     [p.599 of _The Lord of the Rings_, III/xi: "The Palantír"]
 */

/*
=head1 GV Functions

A GV is a structure which corresponds to to a Perl typeglob, ie *foo.
It is a structure that holds a pointer to a scalar, an array, a hash etc,
corresponding to $foo, @foo, %foo.

GVs are usually found as values in stashes (symbol table hashes) where
Perl stores its global variables.

=cut
*/

#include "EXTERN.h"
#define PERL_IN_GV_C
#include "perl.h"
#include "overload.c"
#include "keywords.h"
#include "feature.h"

static const char S_autoload[] = "AUTOLOAD";
static const STRLEN S_autolen = sizeof(S_autoload)-1;

GV *
Perl_gv_add_by_type(pTHX_ GV *gv, svtype type)
{
    SV **where;

    if (
        !gv
     || (
            SvTYPE((const SV *)gv) != SVt_PVGV
         && SvTYPE((const SV *)gv) != SVt_PVLV
        )
    ) {
	const char *what;
	if (type == SVt_PVIO) {
	    /*
	     * if it walks like a dirhandle, then let's assume that
	     * this is a dirhandle.
	     */
	    what = OP_IS_DIRHOP(PL_op->op_type) ?
		"dirhandle" : "filehandle";
	} else if (type == SVt_PVHV) {
	    what = "hash";
	} else {
	    what = type == SVt_PVAV ? "array" : "scalar";
	}
	/* diag_listed_as: Bad symbol for filehandle */
	Perl_croak(aTHX_ "Bad symbol for %s", what);
    }

    if (type == SVt_PVHV) {
	where = (SV **)&GvHV(gv);
    } else if (type == SVt_PVAV) {
	where = (SV **)&GvAV(gv);
    } else if (type == SVt_PVIO) {
	where = (SV **)&GvIOp(gv);
    } else {
	where = &GvSV(gv);
    }

    if (!*where)
    {
	*where = newSV_type(type);
	    if (type == SVt_PVAV && GvNAMELEN(gv) == 3
	     && strnEQ(GvNAME(gv), "ISA", 3))
	    sv_magic(*where, (SV *)gv, PERL_MAGIC_isa, NULL, 0);
    }
    return gv;
}

GV *
Perl_gv_fetchfile(pTHX_ const char *name)
{
    PERL_ARGS_ASSERT_GV_FETCHFILE;
    return gv_fetchfile_flags(name, strlen(name), 0);
}

GV *
Perl_gv_fetchfile_flags(pTHX_ const char *const name, const STRLEN namelen,
			const U32 flags)
{
    dVAR;
    char smallbuf[128];
    char *tmpbuf;
    const STRLEN tmplen = namelen + 2;
    GV *gv;

    PERL_ARGS_ASSERT_GV_FETCHFILE_FLAGS;
    PERL_UNUSED_ARG(flags);

    if (!PL_defstash)
	return NULL;

    if (tmplen <= sizeof smallbuf)
	tmpbuf = smallbuf;
    else
	Newx(tmpbuf, tmplen, char);
    /* This is where the debugger's %{"::_<$filename"} hash is created */
    tmpbuf[0] = '_';
    tmpbuf[1] = '<';
    memcpy(tmpbuf + 2, name, namelen);
    gv = *(GV**)hv_fetch(PL_defstash, tmpbuf, tmplen, TRUE);
    if (!isGV(gv)) {
	gv_init(gv, PL_defstash, tmpbuf, tmplen, FALSE);
#ifdef PERL_DONT_CREATE_GVSV
	GvSV(gv) = newSVpvn(name, namelen);
#else
	sv_setpvn(GvSV(gv), name, namelen);
#endif
    }
    if ((PERLDB_LINE || PERLDB_SAVESRC) && !GvAV(gv))
	    hv_magic(GvHVn(gv), GvAVn(gv), PERL_MAGIC_dbfile);
    if (tmpbuf != smallbuf)
	Safefree(tmpbuf);
    return gv;
}

/*
=for apidoc gv_const_sv

If C<gv> is a typeglob whose subroutine entry is a constant sub eligible for
inlining, or C<gv> is a placeholder reference that would be promoted to such
a typeglob, then returns the value returned by the sub.  Otherwise, returns
NULL.

=cut
*/

SV *
Perl_gv_const_sv(pTHX_ GV *gv)
{
    PERL_ARGS_ASSERT_GV_CONST_SV;

    if (SvTYPE(gv) == SVt_PVGV)
	return cv_const_sv(GvCVu(gv));
    return SvROK(gv) && SvTYPE(SvRV(gv)) != SVt_PVAV ? SvRV(gv) : NULL;
}

GP *
Perl_newGP(pTHX_ GV *const gv)
{
    GP *gp;
    U32 hash;
    const char *file;
    STRLEN len;
#ifndef USE_ITHREADS
    GV *filegv;
#endif
    dVAR;

    PERL_ARGS_ASSERT_NEWGP;
    Newxz(gp, 1, GP);
    gp->gp_egv = gv; /* allow compiler to reuse gv after this */
#ifndef PERL_DONT_CREATE_GVSV
    gp->gp_sv = newSV(0);
#endif

    /* PL_curcop may be null here.  E.g.,
	INIT { bless {} and exit }
       frees INIT before looking up DESTROY (and creating *DESTROY)
    */
    if (PL_curcop) {
	gp->gp_line = CopLINE(PL_curcop); /* 0 otherwise Newxz */
#ifdef USE_ITHREADS
	if (CopFILE(PL_curcop)) {
	    file = CopFILE(PL_curcop);
	    len = strlen(file);
	}
#else
	filegv = CopFILEGV(PL_curcop);
	if (filegv) {
	    file = GvNAME(filegv)+2;
	    len = GvNAMELEN(filegv)-2;
	}
#endif
	else goto no_file;
    }
    else {
	no_file:
	file = "";
	len = 0;
    }

    PERL_HASH(hash, file, len);
    gp->gp_file_hek = share_hek(file, len, hash);
    gp->gp_refcnt = 1;

    return gp;
}

/* Assign CvGV(cv) = gv, handling weak references.
 * See also S_anonymise_cv_maybe */

void
Perl_cvgv_set(pTHX_ CV* cv, GV* gv)
{
    GV * const oldgv = CvGV(cv);
    HEK *hek;
    PERL_ARGS_ASSERT_CVGV_SET;

    if (oldgv == gv)
	return;

    if (oldgv) {
	if (CvCVGV_RC(cv)) {
	    SvREFCNT_dec_NN(oldgv);
	    CvCVGV_RC_off(cv);
	}
	else {
	    sv_del_backref(MUTABLE_SV(oldgv), MUTABLE_SV(cv));
	}
    }
    else if ((hek = CvNAME_HEK(cv))) unshare_hek(hek);

    SvANY(cv)->xcv_gv_u.xcv_gv = gv;
    assert(!CvCVGV_RC(cv));

    if (!gv)
	return;

    if (isGV_with_GP(gv) && GvGP(gv) && (GvCV(gv) == cv || GvFORM(gv) == cv))
	Perl_sv_add_backref(aTHX_ MUTABLE_SV(gv), MUTABLE_SV(cv));
    else {
	CvCVGV_RC_on(cv);
	SvREFCNT_inc_simple_void_NN(gv);
    }
}

/* Assign CvSTASH(cv) = st, handling weak references. */

void
Perl_cvstash_set(pTHX_ CV *cv, HV *st)
{
    HV *oldst = CvSTASH(cv);
    PERL_ARGS_ASSERT_CVSTASH_SET;
    if (oldst == st)
	return;
    if (oldst)
	sv_del_backref(MUTABLE_SV(oldst), MUTABLE_SV(cv));
    SvANY(cv)->xcv_stash = st;
    if (st)
	Perl_sv_add_backref(aTHX_ MUTABLE_SV(st), MUTABLE_SV(cv));
}

/*
=for apidoc gv_init_pvn

Converts a scalar into a typeglob.  This is an incoercible typeglob;
assigning a reference to it will assign to one of its slots, instead of
overwriting it as happens with typeglobs created by SvSetSV.  Converting
any scalar that is SvOK() may produce unpredictable results and is reserved
for perl's internal use.

C<gv> is the scalar to be converted.

C<stash> is the parent stash/package, if any.

C<name> and C<len> give the name.  The name must be unqualified;
that is, it must not include the package name.  If C<gv> is a
stash element, it is the caller's responsibility to ensure that the name
passed to this function matches the name of the element.  If it does not
match, perl's internal bookkeeping will get out of sync.

C<flags> can be set to SVf_UTF8 if C<name> is a UTF8 string, or
the return value of SvUTF8(sv).  It can also take the
GV_ADDMULTI flag, which means to pretend that the GV has been
seen before (i.e., suppress "Used once" warnings).

=for apidoc gv_init

The old form of gv_init_pvn().  It does not work with UTF8 strings, as it
has no flags parameter.  If the C<multi> parameter is set, the
GV_ADDMULTI flag will be passed to gv_init_pvn().

=for apidoc gv_init_pv

Same as gv_init_pvn(), but takes a nul-terminated string for the name
instead of separate char * and length parameters.

=for apidoc gv_init_sv

Same as gv_init_pvn(), but takes an SV * for the name instead of separate
char * and length parameters.  C<flags> is currently unused.

=cut
*/

void
Perl_gv_init_sv(pTHX_ GV *gv, HV *stash, SV* namesv, U32 flags)
{
   char *namepv;
   STRLEN namelen;
   PERL_ARGS_ASSERT_GV_INIT_SV;
   namepv = SvPV(namesv, namelen);
   if (SvUTF8(namesv))
       flags |= SVf_UTF8;
   gv_init_pvn(gv, stash, namepv, namelen, flags);
}

void
Perl_gv_init_pv(pTHX_ GV *gv, HV *stash, const char *name, U32 flags)
{
   PERL_ARGS_ASSERT_GV_INIT_PV;
   gv_init_pvn(gv, stash, name, strlen(name), flags);
}

void
Perl_gv_init_pvn(pTHX_ GV *gv, HV *stash, const char *name, STRLEN len, U32 flags)
{
    dVAR;
    const U32 old_type = SvTYPE(gv);
    const bool doproto = old_type > SVt_NULL;
    char * const proto = (doproto && SvPOK(gv))
	? ((void)(SvIsCOW(gv) && (sv_force_normal((SV *)gv), 0)), SvPVX(gv))
	: NULL;
    const STRLEN protolen = proto ? SvCUR(gv) : 0;
    const U32 proto_utf8  = proto ? SvUTF8(gv) : 0;
    SV *const has_constant = doproto && SvROK(gv) ? SvRV(gv) : NULL;
    const U32 exported_constant = has_constant ? SvPCS_IMPORTED(gv) : 0;

    PERL_ARGS_ASSERT_GV_INIT_PVN;
    assert (!(proto && has_constant));

    if (has_constant) {
	/* The constant has to be a simple scalar type.  */
	switch (SvTYPE(has_constant)) {
	case SVt_PVHV:
	case SVt_PVCV:
	case SVt_PVFM:
	case SVt_PVIO:
            Perl_croak(aTHX_ "Cannot convert a reference to %s to typeglob",
		       sv_reftype(has_constant, 0));
	default: NOOP;
	}
	SvRV_set(gv, NULL);
	SvROK_off(gv);
    }


    if (old_type < SVt_PVGV) {
	if (old_type >= SVt_PV)
	    SvCUR_set(gv, 0);
	sv_upgrade(MUTABLE_SV(gv), SVt_PVGV);
    }
    if (SvLEN(gv)) {
	if (proto) {
	    SvPV_set(gv, NULL);
	    SvLEN_set(gv, 0);
	    SvPOK_off(gv);
	} else
	    Safefree(SvPVX_mutable(gv));
    }
    SvIOK_off(gv);
    isGV_with_GP_on(gv);

    GvGP_set(gv, Perl_newGP(aTHX_ gv));
    GvSTASH(gv) = stash;
    if (stash)
	Perl_sv_add_backref(aTHX_ MUTABLE_SV(stash), MUTABLE_SV(gv));
    gv_name_set(gv, name, len, GV_ADD | ( flags & SVf_UTF8 ? SVf_UTF8 : 0 ));
    if (flags & GV_ADDMULTI || doproto)	/* doproto means it */
	GvMULTI_on(gv);			/* _was_ mentioned */
    if (doproto) {
	CV *cv;
	if (has_constant) {
	    /* newCONSTSUB takes ownership of the reference from us.  */
	    cv = newCONSTSUB_flags(stash, name, len, flags, has_constant);
	    /* In case op.c:S_process_special_blocks stole it: */
	    if (!GvCV(gv))
		GvCV_set(gv, (CV *)SvREFCNT_inc_simple_NN(cv));
	    assert(GvCV(gv) == cv); /* newCONSTSUB should have set this */
	    /* If this reference was a copy of another, then the subroutine
	       must have been "imported", by a Perl space assignment to a GV
	       from a reference to CV.  */
	    if (exported_constant)
		GvIMPORTED_CV_on(gv);
	    CvSTASH_set(cv, PL_curstash); /* XXX Why is this needed? */
	} else {
	    cv = newSTUB(gv,1);
	}
	if (proto) {
	    sv_usepvn_flags(MUTABLE_SV(cv), proto, protolen,
			    SV_HAS_TRAILING_NUL);
            if ( proto_utf8 ) SvUTF8_on(MUTABLE_SV(cv));
	}
    }
}

STATIC void
S_gv_init_svtype(pTHX_ GV *gv, const svtype sv_type)
{
    PERL_ARGS_ASSERT_GV_INIT_SVTYPE;

    switch (sv_type) {
    case SVt_PVIO:
	(void)GvIOn(gv);
	break;
    case SVt_PVAV:
	(void)GvAVn(gv);
	break;
    case SVt_PVHV:
	(void)GvHVn(gv);
	break;
#ifdef PERL_DONT_CREATE_GVSV
    case SVt_NULL:
    case SVt_PVCV:
    case SVt_PVFM:
    case SVt_PVGV:
	break;
    default:
	if(GvSVn(gv)) {
	    /* Work round what appears to be a bug in Sun C++ 5.8 2005/10/13
	       If we just cast GvSVn(gv) to void, it ignores evaluating it for
	       its side effect */
	}
#endif
    }
}

static void core_xsub(pTHX_ CV* cv);

static GV *
S_maybe_add_coresub(pTHX_ HV * const stash, GV *gv,
                          const char * const name, const STRLEN len)
{
    const int code = keyword(name, len, 1);
    static const char file[] = __FILE__;
    CV *cv, *oldcompcv = NULL;
    int opnum = 0;
    bool ampable = TRUE; /* &{}-able */
    COP *oldcurcop = NULL;
    yy_parser *oldparser = NULL;
    I32 oldsavestack_ix = 0;

    assert(gv || stash);
    assert(name);

    if (!code) return NULL; /* Not a keyword */
    switch (code < 0 ? -code : code) {
     /* no support for \&CORE::infix;
        no support for funcs that do not parse like funcs */
    case KEY___DATA__: case KEY___END__: case KEY_and: case KEY_AUTOLOAD:
    case KEY_BEGIN   : case KEY_CHECK  : case KEY_cmp:
    case KEY_default : case KEY_DESTROY:
    case KEY_do      : case KEY_dump   : case KEY_else  : case KEY_elsif  :
    case KEY_END     : case KEY_eq     : case KEY_eval  :
    case KEY_for     : case KEY_foreach: case KEY_format: case KEY_ge     :
    case KEY_given   : case KEY_goto   : case KEY_grep  :
    case KEY_gt   : case KEY_if: case KEY_INIT: case KEY_last: case KEY_le:
    case KEY_local: case KEY_lt: case KEY_m   : case KEY_map : case KEY_my:
    case KEY_ne   : case KEY_next : case KEY_no: case KEY_or: case KEY_our:
    case KEY_package: case KEY_print: case KEY_printf:
    case KEY_q    : case KEY_qq   : case KEY_qr     : case KEY_qw    :
    case KEY_qx   : case KEY_redo : case KEY_require: case KEY_return:
    case KEY_s    : case KEY_say  : case KEY_sort   :
    case KEY_state: case KEY_sub  :
    case KEY_tr   : case KEY_UNITCHECK: case KEY_unless:
    case KEY_until: case KEY_use  : case KEY_when     : case KEY_while :
    case KEY_x    : case KEY_xor  : case KEY_y        :
	return NULL;
    case KEY_chdir:
    case KEY_chomp: case KEY_chop: case KEY_defined: case KEY_delete:
    case KEY_each : case KEY_eof : case KEY_exec   : case KEY_exists:
    case KEY_keys:
    case KEY_lstat:
    case KEY_pop:
    case KEY_push:
    case KEY_shift:
    case KEY_splice: case KEY_split:
    case KEY_stat:
    case KEY_system:
    case KEY_truncate: case KEY_unlink:
    case KEY_unshift:
    case KEY_values:
	ampable = FALSE;
    }
    if (!gv) {
	gv = (GV *)newSV(0);
	gv_init(gv, stash, name, len, TRUE);
    }
    GvMULTI_on(gv);
    if (ampable) {
	ENTER;
	oldcurcop = PL_curcop;
	oldparser = PL_parser;
	lex_start(NULL, NULL, 0);
	oldcompcv = PL_compcv;
	PL_compcv = NULL; /* Prevent start_subparse from setting
	                     CvOUTSIDE. */
	oldsavestack_ix = start_subparse(FALSE,0);
	cv = PL_compcv;
    }
    else {
	/* Avoid calling newXS, as it calls us, and things start to
	   get hairy. */
	cv = MUTABLE_CV(newSV_type(SVt_PVCV));
	GvCV_set(gv,cv);
	GvCVGEN(gv) = 0;
	CvISXSUB_on(cv);
	CvXSUB(cv) = core_xsub;
    }
    CvGV_set(cv, gv); /* This stops new ATTRSUB from setting CvFILE
                         from PL_curcop. */
    (void)gv_fetchfile(file);
    CvFILE(cv) = (char *)file;
    /* XXX This is inefficient, as doing things this order causes
           a prototype check in newATTRSUB.  But we have to do
           it this order as we need an op number before calling
           new ATTRSUB. */
    (void)core_prototype((SV *)cv, name, code, &opnum);
    if (stash)
	(void)hv_store(stash,name,len,(SV *)gv,0);
    if (ampable) {
#ifdef DEBUGGING
        CV *orig_cv = cv;
#endif
	CvLVALUE_on(cv);
        /* newATTRSUB will free the CV and return NULL if we're still
           compiling after a syntax error */
	if ((cv = newATTRSUB_x(
		   oldsavestack_ix, (OP *)gv,
	           NULL,NULL,
	           coresub_op(
	             opnum
	               ? newSVuv((UV)opnum)
	               : newSVpvn(name,len),
	             code, opnum
	           ),
	           TRUE
               )) != NULL) {
            assert(GvCV(gv) == orig_cv);
            if (opnum != OP_VEC && opnum != OP_SUBSTR && opnum != OP_POS
                && opnum != OP_UNDEF)
                CvLVALUE_off(cv); /* Now *that* was a neat trick. */
        }
	LEAVE;
	PL_parser = oldparser;
	PL_curcop = oldcurcop;
	PL_compcv = oldcompcv;
    }
    if (cv) {
        SV *opnumsv = opnum ? newSVuv((UV)opnum) : (SV *)NULL;
        cv_set_call_checker(
          cv, Perl_ck_entersub_args_core, opnumsv ? opnumsv : (SV *)cv
        );
        SvREFCNT_dec(opnumsv);
    }

    return gv;
}

/*
=for apidoc gv_fetchmeth

Like L</gv_fetchmeth_pvn>, but lacks a flags parameter.

=for apidoc gv_fetchmeth_sv

Exactly like L</gv_fetchmeth_pvn>, but takes the name string in the form
of an SV instead of a string/length pair.

=cut
*/

GV *
Perl_gv_fetchmeth_sv(pTHX_ HV *stash, SV *namesv, I32 level, U32 flags)
{
   char *namepv;
   STRLEN namelen;
   PERL_ARGS_ASSERT_GV_FETCHMETH_SV;
   namepv = SvPV(namesv, namelen);
   if (SvUTF8(namesv))
       flags |= SVf_UTF8;
   return gv_fetchmeth_pvn(stash, namepv, namelen, level, flags);
}

/*
=for apidoc gv_fetchmeth_pv

Exactly like L</gv_fetchmeth_pvn>, but takes a nul-terminated string 
instead of a string/length pair.

=cut
*/

GV *
Perl_gv_fetchmeth_pv(pTHX_ HV *stash, const char *name, I32 level, U32 flags)
{
    PERL_ARGS_ASSERT_GV_FETCHMETH_PV;
    return gv_fetchmeth_pvn(stash, name, strlen(name), level, flags);
}

/*
=for apidoc gv_fetchmeth_pvn

Returns the glob with the given C<name> and a defined subroutine or
C<NULL>.  The glob lives in the given C<stash>, or in the stashes
accessible via @ISA and UNIVERSAL::.

The argument C<level> should be either 0 or -1.  If C<level==0>, as a
side-effect creates a glob with the given C<name> in the given C<stash>
which in the case of success contains an alias for the subroutine, and sets
up caching info for this glob.

The only significant values for C<flags> are GV_SUPER and SVf_UTF8.

GV_SUPER indicates that we want to look up the method in the superclasses
of the C<stash>.

The
GV returned from C<gv_fetchmeth> may be a method cache entry, which is not
visible to Perl code.  So when calling C<call_sv>, you should not use
the GV directly; instead, you should use the method's CV, which can be
obtained from the GV with the C<GvCV> macro.

=cut
*/

/* NOTE: No support for tied ISA */

GV *
Perl_gv_fetchmeth_pvn(pTHX_ HV *stash, const char *name, STRLEN len, I32 level, U32 flags)
{
    dVAR;
    GV** gvp;
    AV* linear_av;
    SV** linear_svp;
    SV* linear_sv;
    HV* cstash, *cachestash;
    GV* candidate = NULL;
    CV* cand_cv = NULL;
    GV* topgv = NULL;
    const char *hvname;
    I32 create = (level >= 0) ? 1 : 0;
    I32 items;
    U32 topgen_cmp;
    U32 is_utf8 = flags & SVf_UTF8;

    PERL_ARGS_ASSERT_GV_FETCHMETH_PVN;

    /* UNIVERSAL methods should be callable without a stash */
    if (!stash) {
	create = 0;  /* probably appropriate */
	if(!(stash = gv_stashpvs("UNIVERSAL", 0)))
	    return 0;
    }

    assert(stash);

    hvname = HvNAME_get(stash);
    if (!hvname)
      Perl_croak(aTHX_ "Can't use anonymous symbol table for method lookup");

    assert(hvname);
    assert(name);

    DEBUG_o( Perl_deb(aTHX_ "Looking for %smethod %s in package %s\n",
		      flags & GV_SUPER ? "SUPER " : "",name,hvname) );

    topgen_cmp = HvMROMETA(stash)->cache_gen + PL_sub_generation;

    if (flags & GV_SUPER) {
	if (!HvAUX(stash)->xhv_mro_meta->super)
	    HvAUX(stash)->xhv_mro_meta->super = newHV();
	cachestash = HvAUX(stash)->xhv_mro_meta->super;
    }
    else cachestash = stash;

    /* check locally for a real method or a cache entry */
    gvp = (GV**)hv_fetch(cachestash, name, is_utf8 ? -(I32)len : (I32)len,
			 create);
    if(gvp) {
        topgv = *gvp;
      have_gv:
        assert(topgv);
        if (SvTYPE(topgv) != SVt_PVGV)
            gv_init_pvn(topgv, stash, name, len, GV_ADDMULTI|is_utf8);
        if ((cand_cv = GvCV(topgv))) {
            /* If genuine method or valid cache entry, use it */
            if (!GvCVGEN(topgv) || GvCVGEN(topgv) == topgen_cmp) {
                return topgv;
            }
            else {
                /* stale cache entry, junk it and move on */
	        SvREFCNT_dec_NN(cand_cv);
	        GvCV_set(topgv, NULL);
		cand_cv = NULL;
	        GvCVGEN(topgv) = 0;
            }
        }
        else if (GvCVGEN(topgv) == topgen_cmp) {
            /* cache indicates no such method definitively */
            return 0;
        }
	else if (stash == cachestash
	      && len > 1 /* shortest is uc */ && HvNAMELEN_get(stash) == 4
              && strnEQ(hvname, "CORE", 4)
              && S_maybe_add_coresub(aTHX_ NULL,topgv,name,len))
	    goto have_gv;
    }

    linear_av = mro_get_linear_isa(stash); /* has ourselves at the top of the list */
    linear_svp = AvARRAY(linear_av) + 1; /* skip over self */
    items = AvFILLp(linear_av); /* no +1, to skip over self */
    while (items--) {
        linear_sv = *linear_svp++;
        assert(linear_sv);
        cstash = gv_stashsv(linear_sv, 0);

        if (!cstash) {
	    Perl_ck_warner(aTHX_ packWARN(WARN_SYNTAX),
                           "Can't locate package %"SVf" for @%"HEKf"::ISA",
			   SVfARG(linear_sv),
                           HEKfARG(HvNAME_HEK(stash)));
            continue;
        }

        assert(cstash);

        gvp = (GV**)hv_fetch(cstash, name, is_utf8 ? -(I32)len : (I32)len, 0);
        if (!gvp) {
            if (len > 1 && HvNAMELEN_get(cstash) == 4) {
                const char *hvname = HvNAME(cstash); assert(hvname);
                if (strnEQ(hvname, "CORE", 4)
                 && (candidate =
                      S_maybe_add_coresub(aTHX_ cstash,NULL,name,len)
                    ))
                    goto have_candidate;
            }
            continue;
        }
        else candidate = *gvp;
       have_candidate:
        assert(candidate);
        if (SvTYPE(candidate) != SVt_PVGV)
            gv_init_pvn(candidate, cstash, name, len, GV_ADDMULTI|is_utf8);
        if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) {
            /*
             * Found real method, cache method in topgv if:
             *  1. topgv has no synonyms (else inheritance crosses wires)
             *  2. method isn't a stub (else AUTOLOAD fails spectacularly)
             */
            if (topgv && (GvREFCNT(topgv) == 1) && (CvROOT(cand_cv) || CvXSUB(cand_cv))) {
                  CV *old_cv = GvCV(topgv);
                  SvREFCNT_dec(old_cv);
                  SvREFCNT_inc_simple_void_NN(cand_cv);
                  GvCV_set(topgv, cand_cv);
                  GvCVGEN(topgv) = topgen_cmp;
            }
	    return candidate;
        }
    }

    /* Check UNIVERSAL without caching */
    if(level == 0 || level == -1) {
        candidate = gv_fetchmeth_pvn(NULL, name, len, 1, flags &~GV_SUPER);
        if(candidate) {
            cand_cv = GvCV(candidate);
            if (topgv && (GvREFCNT(topgv) == 1) && (CvROOT(cand_cv) || CvXSUB(cand_cv))) {
                  CV *old_cv = GvCV(topgv);
                  SvREFCNT_dec(old_cv);
                  SvREFCNT_inc_simple_void_NN(cand_cv);
                  GvCV_set(topgv, cand_cv);
                  GvCVGEN(topgv) = topgen_cmp;
            }
            return candidate;
        }
    }

    if (topgv && GvREFCNT(topgv) == 1) {
        /* cache the fact that the method is not defined */
        GvCVGEN(topgv) = topgen_cmp;
    }

    return 0;
}

/*
=for apidoc gv_fetchmeth_autoload

This is the old form of L</gv_fetchmeth_pvn_autoload>, which has no flags
parameter.

=for apidoc gv_fetchmeth_sv_autoload

Exactly like L</gv_fetchmeth_pvn_autoload>, but takes the name string in the form
of an SV instead of a string/length pair.

=cut
*/

GV *
Perl_gv_fetchmeth_sv_autoload(pTHX_ HV *stash, SV *namesv, I32 level, U32 flags)
{
   char *namepv;
   STRLEN namelen;
   PERL_ARGS_ASSERT_GV_FETCHMETH_SV_AUTOLOAD;
   namepv = SvPV(namesv, namelen);
   if (SvUTF8(namesv))
       flags |= SVf_UTF8;
   return gv_fetchmeth_pvn_autoload(stash, namepv, namelen, level, flags);
}

/*
=for apidoc gv_fetchmeth_pv_autoload

Exactly like L</gv_fetchmeth_pvn_autoload>, but takes a nul-terminated string
instead of a string/length pair.

=cut
*/

GV *
Perl_gv_fetchmeth_pv_autoload(pTHX_ HV *stash, const char *name, I32 level, U32 flags)
{
    PERL_ARGS_ASSERT_GV_FETCHMETH_PV_AUTOLOAD;
    return gv_fetchmeth_pvn_autoload(stash, name, strlen(name), level, flags);
}

/*
=for apidoc gv_fetchmeth_pvn_autoload

Same as gv_fetchmeth_pvn(), but looks for autoloaded subroutines too.
Returns a glob for the subroutine.

For an autoloaded subroutine without a GV, will create a GV even
if C<level < 0>.  For an autoloaded subroutine without a stub, GvCV()
of the result may be zero.

Currently, the only significant value for C<flags> is SVf_UTF8.

=cut
*/

GV *
Perl_gv_fetchmeth_pvn_autoload(pTHX_ HV *stash, const char *name, STRLEN len, I32 level, U32 flags)
{
    GV *gv = gv_fetchmeth_pvn(stash, name, len, level, flags);

    PERL_ARGS_ASSERT_GV_FETCHMETH_PVN_AUTOLOAD;

    if (!gv) {
	CV *cv;
	GV **gvp;

	if (!stash)
	    return NULL;	/* UNIVERSAL::AUTOLOAD could cause trouble */
	if (len == S_autolen && memEQ(name, S_autoload, S_autolen))
	    return NULL;
	if (!(gv = gv_fetchmeth_pvn(stash, S_autoload, S_autolen, FALSE, flags)))
	    return NULL;
	cv = GvCV(gv);
	if (!(CvROOT(cv) || CvXSUB(cv)))
	    return NULL;
	/* Have an autoload */
	if (level < 0)	/* Cannot do without a stub */
	    gv_fetchmeth_pvn(stash, name, len, 0, flags);
	gvp = (GV**)hv_fetch(stash, name,
                        (flags & SVf_UTF8) ? -(I32)len : (I32)len, (level >= 0));
	if (!gvp)
	    return NULL;
	return *gvp;
    }
    return gv;
}

/*
=for apidoc gv_fetchmethod_autoload

Returns the glob which contains the subroutine to call to invoke the method
on the C<stash>.  In fact in the presence of autoloading this may be the
glob for "AUTOLOAD".  In this case the corresponding variable $AUTOLOAD is
already setup.

The third parameter of C<gv_fetchmethod_autoload> determines whether
AUTOLOAD lookup is performed if the given method is not present: non-zero
means yes, look for AUTOLOAD; zero means no, don't look for AUTOLOAD.
Calling C<gv_fetchmethod> is equivalent to calling C<gv_fetchmethod_autoload>
with a non-zero C<autoload> parameter.

These functions grant C<"SUPER"> token
as a prefix of the method name.  Note
that if you want to keep the returned glob for a long time, you need to
check for it being "AUTOLOAD", since at the later time the call may load a
different subroutine due to $AUTOLOAD changing its value.  Use the glob
created as a side effect to do this.

These functions have the same side-effects as C<gv_fetchmeth> with
C<level==0>.  The warning against passing the GV returned by
C<gv_fetchmeth> to C<call_sv> applies equally to these functions.

=cut
*/

GV *
Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
{
    PERL_ARGS_ASSERT_GV_FETCHMETHOD_AUTOLOAD;

    return gv_fetchmethod_flags(stash, name, autoload ? GV_AUTOLOAD : 0);
}

GV *
Perl_gv_fetchmethod_sv_flags(pTHX_ HV *stash, SV *namesv, U32 flags)
{
    char *namepv;
    STRLEN namelen;
    PERL_ARGS_ASSERT_GV_FETCHMETHOD_SV_FLAGS;
    namepv = SvPV(namesv, namelen);
    if (SvUTF8(namesv))
       flags |= SVf_UTF8;
    return gv_fetchmethod_pvn_flags(stash, namepv, namelen, flags);
}

GV *
Perl_gv_fetchmethod_pv_flags(pTHX_ HV *stash, const char *name, U32 flags)
{
    PERL_ARGS_ASSERT_GV_FETCHMETHOD_PV_FLAGS;
    return gv_fetchmethod_pvn_flags(stash, name, strlen(name), flags);
}

/* Don't merge this yet, as it's likely to get a len parameter, and possibly
   even a U32 hash */
GV *
Perl_gv_fetchmethod_pvn_flags(pTHX_ HV *stash, const char *name, const STRLEN len, U32 flags)
{
    dVAR;
    const char *nend;
    const char *nsplit = NULL;
    GV* gv;
    HV* ostash = stash;
    const char * const origname = name;
    SV *const error_report = MUTABLE_SV(stash);
    const U32 autoload = flags & GV_AUTOLOAD;
    const U32 do_croak = flags & GV_CROAK;
    const U32 is_utf8  = flags & SVf_UTF8;

    PERL_ARGS_ASSERT_GV_FETCHMETHOD_PVN_FLAGS;

    if (SvTYPE(stash) < SVt_PVHV)
	stash = NULL;
    else {
	/* The only way stash can become NULL later on is if nsplit is set,
	   which in turn means that there is no need for a SVt_PVHV case
	   the error reporting code.  */
    }

    for (nend = name; *nend || nend != (origname + len); nend++) {
	if (*nend == '\'') {
	    nsplit = nend;
	    name = nend + 1;
	}
	else if (*nend == ':' && *(nend + 1) == ':') {
	    nsplit = nend++;
	    name = nend + 1;
	}
    }
    if (nsplit) {
	if ((nsplit - origname) == 5 && memEQ(origname, "SUPER", 5)) {
	    /* ->SUPER::method should really be looked up in original stash */
	    stash = CopSTASH(PL_curcop);
	    flags |= GV_SUPER;
	    DEBUG_o( Perl_deb(aTHX_ "Treating %s as %s::%s\n",
			 origname, HvENAME_get(stash), name) );
	}
	else if ((nsplit - origname) >= 7 &&
		 strnEQ(nsplit - 7, "::SUPER", 7)) {
            /* don't autovifify if ->NoSuchStash::SUPER::method */
	    stash = gv_stashpvn(origname, nsplit - origname - 7, is_utf8);
	    if (stash) flags |= GV_SUPER;
	}
	else {
            /* don't autovifify if ->NoSuchStash::method */
            stash = gv_stashpvn(origname, nsplit - origname, is_utf8);
	}
	ostash = stash;
    }

    gv = gv_fetchmeth_pvn(stash, name, nend - name, 0, flags);
    if (!gv) {
	if (strEQ(name,"import") || strEQ(name,"unimport"))
	    gv = MUTABLE_GV(&PL_sv_yes);
	else if (autoload)
	    gv = gv_autoload_pvn(
		ostash, name, nend - name, GV_AUTOLOAD_ISMETHOD|flags
	    );
	if (!gv && do_croak) {
	    /* Right now this is exclusively for the benefit of S_method_common
	       in pp_hot.c  */
	    if (stash) {
		/* If we can't find an IO::File method, it might be a call on
		 * a filehandle. If IO:File has not been loaded, try to
		 * require it first instead of croaking */
		const char *stash_name = HvNAME_get(stash);
		if (stash_name && memEQs(stash_name, HvNAMELEN_get(stash), "IO::File")
		    && !Perl_hv_common(aTHX_ GvHVn(PL_incgv), NULL,
				       STR_WITH_LEN("IO/File.pm"), 0,
				       HV_FETCH_ISEXISTS, NULL, 0)
		) {
		    require_pv("IO/File.pm");
		    gv = gv_fetchmeth_pvn(stash, name, nend - name, 0, flags);
		    if (gv)
			return gv;
		}
		Perl_croak(aTHX_
			   "Can't locate object method \"%"UTF8f
			   "\" via package \"%"HEKf"\"",
			            UTF8fARG(is_utf8, nend - name, name),
                                    HEKfARG(HvNAME_HEK(stash)));
	    }
	    else {
                SV* packnamesv;

		if (nsplit) {
		    packnamesv = newSVpvn_flags(origname, nsplit - origname,
                                                    SVs_TEMP | is_utf8);
		} else {
		    packnamesv = error_report;
		}

		Perl_croak(aTHX_
			   "Can't locate object method \"%"UTF8f
			   "\" via package \"%"SVf"\""
			   " (perhaps you forgot to load \"%"SVf"\"?)",
			   UTF8fARG(is_utf8, nend - name, name),
                           SVfARG(packnamesv), SVfARG(packnamesv));
	    }
	}
    }
    else if (autoload) {
	CV* const cv = GvCV(gv);
	if (!CvROOT(cv) && !CvXSUB(cv)) {
	    GV* stubgv;
	    GV* autogv;

	    if (CvANON(cv) || !CvGV(cv))
		stubgv = gv;
	    else {
		stubgv = CvGV(cv);
		if (GvCV(stubgv) != cv)		/* orphaned import */
		    stubgv = gv;
	    }
            autogv = gv_autoload_pvn(GvSTASH(stubgv),
                                  GvNAME(stubgv), GvNAMELEN(stubgv),
                                  GV_AUTOLOAD_ISMETHOD
                                   | (GvNAMEUTF8(stubgv) ? SVf_UTF8 : 0));
	    if (autogv)
		gv = autogv;
	}
    }

    return gv;
}

GV*
Perl_gv_autoload_sv(pTHX_ HV *stash, SV* namesv, U32 flags)
{
   char *namepv;
   STRLEN namelen;
   PERL_ARGS_ASSERT_GV_AUTOLOAD_SV;
   namepv = SvPV(namesv, namelen);
   if (SvUTF8(namesv))
       flags |= SVf_UTF8;
   return gv_autoload_pvn(stash, namepv, namelen, flags);
}

GV*
Perl_gv_autoload_pv(pTHX_ HV *stash, const char *namepv, U32 flags)
{
   PERL_ARGS_ASSERT_GV_AUTOLOAD_PV;
   return gv_autoload_pvn(stash, namepv, strlen(namepv), flags);
}

GV*
Perl_gv_autoload_pvn(pTHX_ HV *stash, const char *name, STRLEN len, U32 flags)
{
    dVAR;
    GV* gv;
    CV* cv;
    HV* varstash;
    GV* vargv;
    SV* varsv;
    SV *packname = NULL;
    U32 is_utf8 = flags & SVf_UTF8 ? SVf_UTF8 : 0;

    PERL_ARGS_ASSERT_GV_AUTOLOAD_PVN;

    if (len == S_autolen && memEQ(name, S_autoload, S_autolen))
	return NULL;
    if (stash) {
	if (SvTYPE(stash) < SVt_PVHV) {
            STRLEN packname_len = 0;
            const char * const packname_ptr = SvPV_const(MUTABLE_SV(stash), packname_len);
            packname = newSVpvn_flags(packname_ptr, packname_len,
                                      SVs_TEMP | SvUTF8(stash));
	    stash = NULL;
	}
	else
	    packname = sv_2mortal(newSVhek(HvNAME_HEK(stash)));
	if (flags & GV_SUPER) sv_catpvs(packname, "::SUPER");
    }
    if (!(gv = gv_fetchmeth_pvn(stash, S_autoload, S_autolen, FALSE,
				is_utf8 | (flags & GV_SUPER))))
	return NULL;
    cv = GvCV(gv);

    if (!(CvROOT(cv) || CvXSUB(cv)))
	return NULL;

    /*
     * Inheriting AUTOLOAD for non-methods works ... for now.
     */
    if (
        !(flags & GV_AUTOLOAD_ISMETHOD)
     && (GvCVGEN(gv) || GvSTASH(gv) != stash)
    )
	Perl_ck_warner_d(aTHX_ packWARN(WARN_DEPRECATED),
			 "Use of inherited AUTOLOAD for non-method %"SVf
			 "::%"UTF8f"() is deprecated",
			 SVfARG(packname),
                         UTF8fARG(is_utf8, len, name));

    if (CvISXSUB(cv)) {
        /* Instead of forcing the XSUB do another lookup for $AUTOLOAD
         * and split that value on the last '::', pass along the same data
         * via the SvPVX field in the CV, and the stash in CvSTASH.
         *
         * Due to an unfortunate accident of history, the SvPVX field
         * serves two purposes.  It is also used for the subroutine's pro-
         * type.  Since SvPVX has been documented as returning the sub name
         * for a long time, but not as returning the prototype, we have
         * to preserve the SvPVX AUTOLOAD behaviour and put the prototype
         * elsewhere.
         *
         * We put the prototype in the same allocated buffer, but after
         * the sub name.  The SvPOK flag indicates the presence of a proto-
         * type.  The CvAUTOLOAD flag indicates the presence of a sub name.
         * If both flags are on, then SvLEN is used to indicate the end of
         * the prototype (artificially lower than what is actually allo-
         * cated), at the risk of having to reallocate a few bytes unneces-
         * sarily--but that should happen very rarely, if ever.
         *
         * We use SvUTF8 for both prototypes and sub names, so if one is
         * UTF8, the other must be upgraded.
         */
	CvSTASH_set(cv, stash);
	if (SvPOK(cv)) { /* Ouch! */
	    SV * const tmpsv = newSVpvn_flags(name, len, is_utf8);
	    STRLEN ulen;
	    const char *proto = CvPROTO(cv);
	    assert(proto);
	    if (SvUTF8(cv))
		sv_utf8_upgrade_flags_grow(tmpsv, 0, CvPROTOLEN(cv) + 2);
	    ulen = SvCUR(tmpsv);
	    SvCUR(tmpsv)++; /* include null in string */
	    sv_catpvn_flags(
		tmpsv, proto, CvPROTOLEN(cv), SV_CATBYTES*!SvUTF8(cv)
	    );
	    SvTEMP_on(tmpsv); /* Allow theft */
	    sv_setsv_nomg((SV *)cv, tmpsv);
	    SvTEMP_off(tmpsv);
	    SvREFCNT_dec_NN(tmpsv);
	    SvLEN(cv) = SvCUR(cv) + 1;
	    SvCUR(cv) = ulen;
	}
	else {
	  sv_setpvn((SV *)cv, name, len);
	  SvPOK_off(cv);
	  if (is_utf8)
            SvUTF8_on(cv);
	  else SvUTF8_off(cv);
	}
	CvAUTOLOAD_on(cv);
    }

    /*
     * Given &FOO::AUTOLOAD, set $FOO::AUTOLOAD to desired function name.
     * The subroutine's original name may not be "AUTOLOAD", so we don't
     * use that, but for lack of anything better we will use the sub's
     * original package to look up $AUTOLOAD.
     */
    varstash = CvNAMED(cv) ? CvSTASH(cv) : GvSTASH(CvGV(cv));
    vargv = *(GV**)hv_fetch(varstash, S_autoload, S_autolen, TRUE);
    ENTER;

    if (!isGV(vargv)) {
	gv_init_pvn(vargv, varstash, S_autoload, S_autolen, 0);
#ifdef PERL_DONT_CREATE_GVSV
	GvSV(vargv) = newSV(0);
#endif
    }
    LEAVE;
    varsv = GvSVn(vargv);
    SvTAINTED_off(varsv); /* previous $AUTOLOAD taint is obsolete */
    /* XXX: this process is not careful to avoid extra magic gets and sets; tied $AUTOLOAD will get noise */
    sv_setsv(varsv, packname);
    sv_catpvs(varsv, "::");
    /* Ensure SvSETMAGIC() is called if necessary. In particular, to clear
       tainting if $FOO::AUTOLOAD was previously tainted, but is not now.  */
    sv_catpvn_flags(
	varsv, name, len,
	SV_SMAGIC|(is_utf8 ? SV_CATUTF8 : SV_CATBYTES)
    );
    if (is_utf8)
        SvUTF8_on(varsv);
    return gv;
}


/* require_tie_mod() internal routine for requiring a module
 * that implements the logic of automatic ties like %! and %-
 *
 * The "gv" parameter should be the glob.
 * "varpv" holds the name of the var, used for error messages.
 * "namesv" holds the module name. Its refcount will be decremented.
 * "methpv" holds the method name to test for to check that things
 *   are working reasonably close to as expected.
 * "flags": if flag & 1 then save the scalar before loading.
 * For the protection of $! to work (it is set by this routine)
 * the sv slot must already be magicalized.
 */
STATIC HV*
S_require_tie_mod(pTHX_ GV *gv, const char *varpv, SV* namesv, const char *methpv,const U32 flags)
{
    dVAR;
    HV* stash = gv_stashsv(namesv, 0);

    PERL_ARGS_ASSERT_REQUIRE_TIE_MOD;

    if (!stash || !(gv_fetchmethod_autoload(stash, methpv, FALSE))) {
	SV *module = newSVsv(namesv);
	char varname = *varpv; /* varpv might be clobbered by load_module,
				  so save it. For the moment it's always
				  a single char. */
	const char type = varname == '[' ? '$' : '%';
#ifdef DEBUGGING
	dSP;
#endif
	ENTER;
	SAVEFREESV(namesv);
	if ( flags & 1 )
	    save_scalar(gv);
	Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT, module, NULL);
	assert(sp == PL_stack_sp);
	stash = gv_stashsv(namesv, 0);
	if (!stash)
	    Perl_croak(aTHX_ "panic: Can't use %c%c because %"SVf" is not available",
		    type, varname, SVfARG(namesv));
	else if (!gv_fetchmethod(stash, methpv))
	    Perl_croak(aTHX_ "panic: Can't use %c%c because %"SVf" does not support method %s",
		    type, varname, SVfARG(namesv), methpv);
	LEAVE;
    }
    else SvREFCNT_dec_NN(namesv);
    return stash;
}

/*
=for apidoc gv_stashpv

Returns a pointer to the stash for a specified package.  Uses C<strlen> to
determine the length of C<name>, then calls C<gv_stashpvn()>.

=cut
*/

HV*
Perl_gv_stashpv(pTHX_ const char *name, I32 create)
{
    PERL_ARGS_ASSERT_GV_STASHPV;
    return gv_stashpvn(name, strlen(name), create);
}

/*
=for apidoc gv_stashpvn

Returns a pointer to the stash for a specified package.  The C<namelen>
parameter indicates the length of the C<name>, in bytes.  C<flags> is passed
to C<gv_fetchpvn_flags()>, so if set to C<GV_ADD> then the package will be
created if it does not already exist.  If the package does not exist and
C<flags> is 0 (or any other setting that does not create packages) then NULL
is returned.

Flags may be one of:

    GV_ADD
    SVf_UTF8
    GV_NOADD_NOINIT
    GV_NOINIT
    GV_NOEXPAND
    GV_ADDMG

The most important of which are probably GV_ADD and SVf_UTF8.

=cut
*/

HV*
Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 flags)
{
    char smallbuf[128];
    char *tmpbuf;
    HV *stash;
    GV *tmpgv;
    U32 tmplen = namelen + 2;

    PERL_ARGS_ASSERT_GV_STASHPVN;

    if (tmplen <= sizeof smallbuf)
	tmpbuf = smallbuf;
    else
	Newx(tmpbuf, tmplen, char);
    Copy(name, tmpbuf, namelen, char);
    tmpbuf[namelen]   = ':';
    tmpbuf[namelen+1] = ':';
    tmpgv = gv_fetchpvn_flags(tmpbuf, tmplen, flags, SVt_PVHV);
    if (tmpbuf != smallbuf)
	Safefree(tmpbuf);
    if (!tmpgv)
	return NULL;
    stash = GvHV(tmpgv);
    if (!(flags & ~GV_NOADD_MASK) && !stash) return NULL;
    assert(stash);
    if (!HvNAME_get(stash)) {
	hv_name_set(stash, name, namelen, flags & SVf_UTF8 ? SVf_UTF8 : 0 );
	
	/* FIXME: This is a repeat of logic in gv_fetchpvn_flags */
	/* If the containing stash has multiple effective
	   names, see that this one gets them, too. */
	if (HvAUX(GvSTASH(tmpgv))->xhv_name_count)
	    mro_package_moved(stash, NULL, tmpgv, 1);
    }
    return stash;
}

/*
=for apidoc gv_stashsv

Returns a pointer to the stash for a specified package.  See C<gv_stashpvn>.

=cut
*/

HV*
Perl_gv_stashsv(pTHX_ SV *sv, I32 flags)
{
    STRLEN len;
    const char * const ptr = SvPV_const(sv,len);

    PERL_ARGS_ASSERT_GV_STASHSV;

    return gv_stashpvn(ptr, len, flags | SvUTF8(sv));
}


GV *
Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, const svtype sv_type) {
    PERL_ARGS_ASSERT_GV_FETCHPV;
    return gv_fetchpvn_flags(nambeg, strlen(nambeg), add, sv_type);
}

GV *
Perl_gv_fetchsv(pTHX_ SV *name, I32 flags, const svtype sv_type) {
    STRLEN len;
    const char * const nambeg =
       SvPV_flags_const(name, len, flags & GV_NO_SVGMAGIC ? 0 : SV_GMAGIC);
    PERL_ARGS_ASSERT_GV_FETCHSV;
    return gv_fetchpvn_flags(nambeg, len, flags | SvUTF8(name), sv_type);
}

PERL_STATIC_INLINE void
S_gv_magicalize_isa(pTHX_ GV *gv)
{
    AV* av;

    PERL_ARGS_ASSERT_GV_MAGICALIZE_ISA;

    av = GvAVn(gv);
    GvMULTI_on(gv);
    sv_magic(MUTABLE_SV(av), MUTABLE_SV(gv), PERL_MAGIC_isa,
	     NULL, 0);
}

/* This function grabs name and tries to split a stash and glob
 * from its contents. TODO better description, comments
 * 
 * If the function returns TRUE and 'name == name_end', then
 * 'gv' can be directly returned to the caller of gv_fetchpvn_flags
 */
PERL_STATIC_INLINE bool
S_parse_gv_stash_name(pTHX_ HV **stash, GV **gv, const char **name,
               STRLEN *len, const char *nambeg, STRLEN full_len,
               const U32 is_utf8, const I32 add)
{
    const char *name_cursor;
    const char *const name_end = nambeg + full_len;
    const char *const name_em1 = name_end - 1;

    PERL_ARGS_ASSERT_PARSE_GV_STASH_NAME;
    
    if (full_len > 2 && **name == '*' && isIDFIRST_lazy_if(*name + 1, is_utf8)) {
        /* accidental stringify on a GV? */
        (*name)++;
    }

    for (name_cursor = *name; name_cursor < name_end; name_cursor++) {
        if (name_cursor < name_em1 &&
            ((*name_cursor == ':' && name_cursor[1] == ':')
           || *name_cursor == '\''))
        {
            if (!*stash)
                *stash = PL_defstash;
            if (!*stash || !SvREFCNT(*stash)) /* symbol table under destruction */
                return FALSE;

            *len = name_cursor - *name;
            if (name_cursor > nambeg) { /* Skip for initial :: or ' */
                const char *key;
                GV**gvp;
                if (*name_cursor == ':') {
                    key = *name;
                    *len += 2;
                }
                else {
                    char *tmpbuf;
                    Newx(tmpbuf, *len+2, char);
                    Copy(*name, tmpbuf, *len, char);
                    tmpbuf[(*len)++] = ':';
                    tmpbuf[(*len)++] = ':';
                    key = tmpbuf;
                }
                gvp = (GV**)hv_fetch(*stash, key, is_utf8 ? -((I32)*len) : (I32)*len, add);
                *gv = gvp ? *gvp : NULL;
                if (*gv && *gv != (const GV *)&PL_sv_undef) {
                    if (SvTYPE(*gv) != SVt_PVGV)
                        gv_init_pvn(*gv, *stash, key, *len, (add & GV_ADDMULTI)|is_utf8);
                    else
                        GvMULTI_on(*gv);
                }
                if (key != *name)
                    Safefree(key);
                if (!*gv || *gv == (const GV *)&PL_sv_undef)
                    return FALSE;

                if (!(*stash = GvHV(*gv))) {
                    *stash = GvHV(*gv) = newHV();
                    if (!HvNAME_get(*stash)) {
                        if (GvSTASH(*gv) == PL_defstash && *len == 6
                            && strnEQ(*name, "CORE", 4))
                            hv_name_set(*stash, "CORE", 4, 0);
                        else
                            hv_name_set(
                                *stash, nambeg, name_cursor-nambeg, is_utf8
                            );
                    /* If the containing stash has multiple effective
                    names, see that this one gets them, too. */
                    if (HvAUX(GvSTASH(*gv))->xhv_name_count)
                        mro_package_moved(*stash, NULL, *gv, 1);
                    }
                }
                else if (!HvNAME_get(*stash))
                    hv_name_set(*stash, nambeg, name_cursor - nambeg, is_utf8);
            }

            if (*name_cursor == ':')
                name_cursor++;
            *name = name_cursor+1;
            if (*name == name_end) {
                if (!*gv)
                    *gv = MUTABLE_GV(*hv_fetchs(PL_defstash, "main::", TRUE));
                return TRUE;
            }
        }
    }
    *len = name_cursor - *name;
    return TRUE;
}

/* Checks if an unqualified name is in the main stash */
PERL_STATIC_INLINE bool
S_gv_is_in_main(pTHX_ const char *name, STRLEN len, const U32 is_utf8)
{
    PERL_ARGS_ASSERT_GV_IS_IN_MAIN;
    
    /* If it's an alphanumeric variable */
    if ( len && isIDFIRST_lazy_if(name, is_utf8) ) {
        /* Some "normal" variables are always in main::,
         * like INC or STDOUT.
         */
        switch (len) {
            case 1:
            if (*name == '_')
                return TRUE;
            break;
            case 3:
            if ((name[0] == 'I' && name[1] == 'N' && name[2] == 'C')
                || (name[0] == 'E' && name[1] == 'N' && name[2] == 'V')
                || (name[0] == 'S' && name[1] == 'I' && name[2] == 'G'))
                return TRUE;
            break;
            case 4:
            if (name[0] == 'A' && name[1] == 'R' && name[2] == 'G'
                && name[3] == 'V')
                return TRUE;
            break;
            case 5:
            if (name[0] == 'S' && name[1] == 'T' && name[2] == 'D'
                && name[3] == 'I' && name[4] == 'N')
                return TRUE;
            break;
            case 6:
            if ((name[0] == 'S' && name[1] == 'T' && name[2] == 'D')
                &&((name[3] == 'O' && name[4] == 'U' && name[5] == 'T')
                    ||(name[3] == 'E' && name[4] == 'R' && name[5] == 'R')))
                return TRUE;
            break;
            case 7:
            if (name[0] == 'A' && name[1] == 'R' && name[2] == 'G'
                && name[3] == 'V' && name[4] == 'O' && name[5] == 'U'
                && name[6] == 'T')
                return TRUE;
            break;
        }
    }
    /* *{""}, or a special variable like $@ */
    else
        return TRUE;
    
    return FALSE;
}


/* This function is called if parse_gv_stash_name() failed to
 * find a stash, or if GV_NOTQUAL or an empty name was passed
 * to gv_fetchpvn_flags.
 * 
 * It returns FALSE if the default stash can't be found nor created,
 * which might happen during global destruction.
 */
PERL_STATIC_INLINE bool
S_find_default_stash(pTHX_ HV **stash, const char *name, STRLEN len,
               const U32 is_utf8, const I32 add,
               const svtype sv_type)
{
    PERL_ARGS_ASSERT_FIND_DEFAULT_STASH;
    
    /* No stash in name, so see how we can default */

    if ( gv_is_in_main(name, len, is_utf8) ) {
        *stash = PL_defstash;
    }
    else {
        if (IN_PERL_COMPILETIME) {
            *stash = PL_curstash;
            if (add && (PL_hints & HINT_STRICT_VARS) &&
                sv_type != SVt_PVCV &&
                sv_type != SVt_PVGV &&
                sv_type != SVt_PVFM &&
                sv_type != SVt_PVIO &&
                !(len == 1 && sv_type == SVt_PV &&
                (*name == 'a' || *name == 'b')) )
            {
                GV**gvp = (GV**)hv_fetch(*stash,name,is_utf8 ? -(I32)len : (I32)len,0);
                if (!gvp || *gvp == (const GV *)&PL_sv_undef ||
                    SvTYPE(*gvp) != SVt_PVGV)
                {
                    *stash = NULL;
                }
                else if ((sv_type == SVt_PV   && !GvIMPORTED_SV(*gvp)) ||
                         (sv_type == SVt_PVAV && !GvIMPORTED_AV(*gvp)) ||
                         (sv_type == SVt_PVHV && !GvIMPORTED_HV(*gvp)) )
                {
                    /* diag_listed_as: Variable "%s" is not imported%s */
                    Perl_ck_warner_d(
                        aTHX_ packWARN(WARN_MISC),
                        "Variable \"%c%"UTF8f"\" is not imported",
                        sv_type == SVt_PVAV ? '@' :
                        sv_type == SVt_PVHV ? '%' : '$',
                        UTF8fARG(is_utf8, len, name));
                    if (GvCVu(*gvp))
                        Perl_ck_warner_d(
                            aTHX_ packWARN(WARN_MISC),
                            "\t(Did you mean &%"UTF8f" instead?)\n",
                            UTF8fARG(is_utf8, len, name)
                        );
                    *stash = NULL;
                }
            }
        }
        else {
            /* Use the current op's stash */
            *stash = CopSTASH(PL_curcop);
        }
    }

    if (!*stash) {
        if (add && !PL_in_clean_all) {
            SV * const err = Perl_mess(aTHX_
                 "Global symbol \"%s%"UTF8f
                 "\" requires explicit package name",
                 (sv_type == SVt_PV ? "$"
                  : sv_type == SVt_PVAV ? "@"
                  : sv_type == SVt_PVHV ? "%"
                  : ""), UTF8fARG(is_utf8, len, name));
            GV *gv;
            if (is_utf8)
                SvUTF8_on(err);
            qerror(err);
            /* To maintain the output of errors after the strict exception
             * above, and to keep compat with older releases, rather than
             * placing the variables in the pad, we place
             * them in the <none>:: stash.
             */
            gv = gv_fetchpvs("<none>::", GV_ADDMULTI, SVt_PVHV);
            if (!gv) {
                /* symbol table under destruction */
                return FALSE;
            }
            *stash = GvHV(gv);
        }
        else
            return FALSE;
    }

    if (!SvREFCNT(*stash))   /* symbol table under destruction */
        return FALSE;

    return TRUE;
}

/* gv_magicalize() is called by gv_fetchpvn_flags when creating
 * a new GV.
 * Note that it does not insert the GV into the stash prior to
 * magicalization, which some variables require need in order
 * to work (like $[, %+, %-, %!), so callers must take care of
 * that beforehand.
 * 
 * The return value has a specific meaning for gv_fetchpvn_flags:
 * If it returns true, and the gv is empty, it indicates that its
 * refcount should be decreased.
 */
PERL_STATIC_INLINE bool
S_gv_magicalize(pTHX_ GV *gv, HV *stash, const char *name, STRLEN len,
               bool addmg, const svtype sv_type)
{
    SSize_t paren;

    PERL_ARGS_ASSERT_GV_MAGICALIZE;
    
    if (stash != PL_defstash) { /* not the main stash */
	/* We only have to check for a few names here: a, b, EXPORT, ISA
	   and VERSION. All the others apply only to the main stash or to
	   CORE (which is checked right after this). */
	if (len) {
	    const char * const name2 = name + 1;
	    switch (*name) {
	    case 'E':
		if (strnEQ(name2, "XPORT", 5))
		    GvMULTI_on(gv);
		break;
	    case 'I':
		if (strEQ(name2, "SA"))
		    gv_magicalize_isa(gv);
		break;
	    case 'V':
		if (strEQ(name2, "ERSION"))
		    GvMULTI_on(gv);
		break;
	    case 'a':
	    case 'b':
		if (len == 1 && sv_type == SVt_PV)
		    GvMULTI_on(gv);
		/* FALL THROUGH */
	    default:
		goto try_core;
	    }
	    return addmg;
	}
      try_core:
	if (len > 1 /* shortest is uc */ && HvNAMELEN_get(stash) == 4) {
	  /* Avoid null warning: */
	  const char * const stashname = HvNAME(stash); assert(stashname);
	  if (strnEQ(stashname, "CORE", 4))
	    S_maybe_add_coresub(aTHX_ 0, gv, name, len);
	}
    }
    else if (len > 1) {
#ifndef EBCDIC
	if (*name > 'V' ) {
	    NOOP;
	    /* Nothing else to do.
	       The compiler will probably turn the switch statement into a
	       branch table. Make sure we avoid even that small overhead for
               the common case of lower case variable names.  (On EBCDIC
               platforms, we can't just do:
                 if (NATIVE_TO_ASCII(*name) > NATIVE_TO_ASCII('V') ) {
               because cases like '\027' in the switch statement below are
               C1 (non-ASCII) controls on those platforms, so the remapping
               would make them larger than 'V')
             */
	} else
#endif
	{
	    const char * const name2 = name + 1;
	    switch (*name) {
	    case 'A':
		if (strEQ(name2, "RGV")) {
		    IoFLAGS(GvIOn(gv)) |= IOf_ARGV|IOf_START;
		}
		else if (strEQ(name2, "RGVOUT")) {
		    GvMULTI_on(gv);
		}
		break;
	    case 'E':
		if (strnEQ(name2, "XPORT", 5))
		    GvMULTI_on(gv);
		break;
	    case 'I':
		if (strEQ(name2, "SA")) {
		    gv_magicalize_isa(gv);
		}
		break;
	    case 'S':
		if (strEQ(name2, "IG")) {
		    HV *hv;
		    I32 i;
		    if (!PL_psig_name) {
			Newxz(PL_psig_name, 2 * SIG_SIZE, SV*);
			Newxz(PL_psig_pend, SIG_SIZE, int);
			PL_psig_ptr = PL_psig_name + SIG_SIZE;
		    } else {
			/* I think that the only way to get here is to re-use an
			   embedded perl interpreter, where the previous
			   use didn't clean up fully because
			   PL_perl_destruct_level was 0. I'm not sure that we
			   "support" that, in that I suspect in that scenario
			   there are sufficient other garbage values left in the
			   interpreter structure that something else will crash
			   before we get here. I suspect that this is one of
			   those "doctor, it hurts when I do this" bugs.  */
			Zero(PL_psig_name, 2 * SIG_SIZE, SV*);
			Zero(PL_psig_pend, SIG_SIZE, int);
		    }
		    GvMULTI_on(gv);
		    hv = GvHVn(gv);
		    hv_magic(hv, NULL, PERL_MAGIC_sig);
		    for (i = 1; i < SIG_SIZE; i++) {
			SV * const * const init = hv_fetch(hv, PL_sig_name[i], strlen(PL_sig_name[i]), 1);
			if (init)
			    sv_setsv(*init, &PL_sv_undef);
		    }
		}
		break;
	    case 'V':
		if (strEQ(name2, "ERSION"))
		    GvMULTI_on(gv);
		break;
            case '\003':        /* $^CHILD_ERROR_NATIVE */
		if (strEQ(name2, "HILD_ERROR_NATIVE"))
		    goto magicalize;
		break;
	    case '\005':	/* $^ENCODING */
		if (strEQ(name2, "NCODING"))
		    goto magicalize;
		break;
	    case '\007':	/* $^GLOBAL_PHASE */
		if (strEQ(name2, "LOBAL_PHASE"))
		    goto ro_magicalize;
		break;
	    case '\014':	/* $^LAST_FH */
		if (strEQ(name2, "AST_FH"))
		    goto ro_magicalize;
		break;
            case '\015':        /* $^MATCH */
                if (strEQ(name2, "ATCH")) {
                    paren = RX_BUFF_IDX_CARET_FULLMATCH;
                    goto storeparen;
                }
                break;
	    case '\017':	/* $^OPEN */
		if (strEQ(name2, "PEN"))
		    goto magicalize;
		break;
	    case '\020':        /* $^PREMATCH  $^POSTMATCH */
                if (strEQ(name2, "REMATCH")) {
                    paren = RX_BUFF_IDX_CARET_PREMATCH;
                    goto storeparen;
                }
	        if (strEQ(name2, "OSTMATCH")) {
                    paren = RX_BUFF_IDX_CARET_POSTMATCH;
                    goto storeparen;
                }
		break;
	    case '\024':	/* ${^TAINT} */
		if (strEQ(name2, "AINT"))
		    goto ro_magicalize;
		break;
	    case '\025':	/* ${^UNICODE}, ${^UTF8LOCALE} */
		if (strEQ(name2, "NICODE"))
		    goto ro_magicalize;
		if (strEQ(name2, "TF8LOCALE"))
		    goto ro_magicalize;
		if (strEQ(name2, "TF8CACHE"))
		    goto magicalize;
		break;
	    case '\027':	/* $^WARNING_BITS */
		if (strEQ(name2, "ARNING_BITS"))
		    goto magicalize;
		break;
	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
	    case '8':
	    case '9':
	    {
		/* Ensures that we have an all-digit variable, ${"1foo"} fails
		   this test  */
		/* This snippet is taken from is_gv_magical */
		const char *end = name + len;
		while (--end > name) {
		    if (!isDIGIT(*end))
                        return addmg;
		}
                paren = strtoul(name, NULL, 10);
                goto storeparen;
	    }
	    }
	}
    } else {
	/* Names of length 1.  (Or 0. But name is NUL terminated, so that will
	   be case '\0' in this switch statement (ie a default case)  */
	switch (*name) {
	case '&':		/* $& */
            paren = RX_BUFF_IDX_FULLMATCH;
            goto sawampersand;
	case '`':		/* $` */
            paren = RX_BUFF_IDX_PREMATCH;
            goto sawampersand;
	case '\'':		/* $' */
            paren = RX_BUFF_IDX_POSTMATCH;
        sawampersand:
#ifdef PERL_SAWAMPERSAND
	    if (!(
		sv_type == SVt_PVAV ||
		sv_type == SVt_PVHV ||
		sv_type == SVt_PVCV ||
		sv_type == SVt_PVFM ||
		sv_type == SVt_PVIO
		)) { PL_sawampersand |=
                        (*name == '`')
                            ? SAWAMPERSAND_LEFT
                            : (*name == '&')
                                ? SAWAMPERSAND_MIDDLE
                                : SAWAMPERSAND_RIGHT;
                }
#endif
            goto storeparen;
        case '1':               /* $1 */
        case '2':               /* $2 */
        case '3':               /* $3 */
        case '4':               /* $4 */
        case '5':               /* $5 */
        case '6':               /* $6 */
        case '7':               /* $7 */
        case '8':               /* $8 */
        case '9':               /* $9 */
            paren = *name - '0';

        storeparen:
            /* Flag the capture variables with a NULL mg_ptr
               Use mg_len for the array index to lookup.  */
            sv_magic(GvSVn(gv), MUTABLE_SV(gv), PERL_MAGIC_sv, NULL, paren);
            break;

	case ':':		/* $: */
	    sv_setpv(GvSVn(gv),PL_chopset);
	    goto magicalize;

	case '?':		/* $? */
#ifdef COMPLEX_STATUS
	    SvUPGRADE(GvSVn(gv), SVt_PVLV);
#endif
	    goto magicalize;

	case '!':		/* $! */
	    GvMULTI_on(gv);
	    /* If %! has been used, automatically load Errno.pm. */

	    sv_magic(GvSVn(gv), MUTABLE_SV(gv), PERL_MAGIC_sv, name, len);

            /* magicalization must be done before require_tie_mod is called */
	    if (sv_type == SVt_PVHV || sv_type == SVt_PVGV)
	    {
		require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);
                addmg = FALSE;
	    }

	    break;
	case '-':		/* $- */
	case '+':		/* $+ */
	GvMULTI_on(gv); /* no used once warnings here */
        {
            AV* const av = GvAVn(gv);
	    SV* const avc = (*name == '+') ? MUTABLE_SV(av) : NULL;

	    sv_magic(MUTABLE_SV(av), avc, PERL_MAGIC_regdata, NULL, 0);
            sv_magic(GvSVn(gv), MUTABLE_SV(gv), PERL_MAGIC_sv, name, len);
            if (avc)
                SvREADONLY_on(GvSVn(gv));
            SvREADONLY_on(av);

            if (sv_type == SVt_PVHV || sv_type == SVt_PVGV)
	    {
                require_tie_mod(gv, name, newSVpvs("Tie::Hash::NamedCapture"), "TIEHASH", 0);
                addmg = FALSE;
	    }

            break;
	}
	case '*':		/* $* */
	case '#':		/* $# */
	    if (sv_type == SVt_PV)
		/* diag_listed_as: $* is no longer supported */
		Perl_ck_warner_d(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
				 "$%c is no longer supported", *name);
	    break;
	case '\010':	/* $^H */
	    {
		HV *const hv = GvHVn(gv);
		hv_magic(hv, NULL, PERL_MAGIC_hints);
	    }
	    goto magicalize;
	case '[':		/* $[ */
	    if ((sv_type == SVt_PV || sv_type == SVt_PVGV)
	     && FEATURE_ARYBASE_IS_ENABLED) {
		require_tie_mod(gv,name,newSVpvs("arybase"),"FETCH",0);
                addmg = FALSE;
	    }
	    else goto magicalize;
            break;
	case '\023':	/* $^S */
	ro_magicalize:
	    SvREADONLY_on(GvSVn(gv));
	    /* FALL THROUGH */
	case '0':		/* $0 */
	case '^':		/* $^ */
	case '~':		/* $~ */
	case '=':		/* $= */
	case '%':		/* $% */
	case '.':		/* $. */
	case '(':		/* $( */
	case ')':		/* $) */
	case '<':		/* $< */
	case '>':		/* $> */
	case '\\':		/* $\ */
	case '/':		/* $/ */
	case '|':		/* $| */
	case '$':		/* $$ */
	case '\001':	/* $^A */
	case '\003':	/* $^C */
	case '\004':	/* $^D */
	case '\005':	/* $^E */
	case '\006':	/* $^F */
	case '\011':	/* $^I, NOT \t in EBCDIC */
	case '\016':	/* $^N */
	case '\017':	/* $^O */
	case '\020':	/* $^P */
	case '\024':	/* $^T */
	case '\027':	/* $^W */
	magicalize:
	    sv_magic(GvSVn(gv), MUTABLE_SV(gv), PERL_MAGIC_sv, name, len);
	    break;

	case '\014':	/* $^L */
	    sv_setpvs(GvSVn(gv),"\f");
	    break;
	case ';':		/* $; */
	    sv_setpvs(GvSVn(gv),"\034");
	    break;
	case ']':		/* $] */
	{
	    SV * const sv = GvSV(gv);
	    if (!sv_derived_from(PL_patchlevel, "version"))
		upg_version(PL_patchlevel, TRUE);
	    GvSV(gv) = vnumify(PL_patchlevel);
	    SvREADONLY_on(GvSV(gv));
	    SvREFCNT_dec(sv);
	}
	break;
	case '\026':	/* $^V */
	{
	    SV * const sv = GvSV(gv);
	    GvSV(gv) = new_version(PL_patchlevel);
	    SvREADONLY_on(GvSV(gv));
	    SvREFCNT_dec(sv);
	}
	break;
	case 'a':
	case 'b':
	    if (sv_type == SVt_PV)
		GvMULTI_on(gv);
	}
    }

    return addmg;
}

/* This function is called when the stash already holds the GV of the magic
 * variable we're looking for, but we need to check that it has the correct
 * kind of magic.  For example, if someone first uses $! and then %!, the
 * latter would end up here, and we add the Errno tie to the HASH slot of
 * the *! glob.
 */
PERL_STATIC_INLINE void
S_maybe_multimagic_gv(pTHX_ GV *gv, const char *name, const svtype sv_type)
{
    PERL_ARGS_ASSERT_MAYBE_MULTIMAGIC_GV;

    if (sv_type == SVt_PVHV || sv_type == SVt_PVGV) {
        if (*name == '!')
            require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);
        else if (*name == '-' || *name == '+')
            require_tie_mod(gv, name, newSVpvs("Tie::Hash::NamedCapture"), "TIEHASH", 0);
    } else if (sv_type == SVt_PV) {
        if (*name == '*' || *name == '#') {
            /* diag_listed_as: $* is no longer supported */
            Perl_ck_warner_d(aTHX_ packWARN2(WARN_DEPRECATED,
                                             WARN_SYNTAX),
                             "$%c is no longer supported", *name);
        }
    }
    if (sv_type==SVt_PV || sv_type==SVt_PVGV) {
      switch (*name) {
      case '[':
          require_tie_mod(gv,name,newSVpvs("arybase"),"FETCH",0);
          break;
#ifdef PERL_SAWAMPERSAND
      case '`':
          PL_sawampersand |= SAWAMPERSAND_LEFT;
          (void)GvSVn(gv);
          break;
      case '&':
          PL_sawampersand |= SAWAMPERSAND_MIDDLE;
          (void)GvSVn(gv);
          break;
      case '\'':
          PL_sawampersand |= SAWAMPERSAND_RIGHT;
          (void)GvSVn(gv);
          break;
#endif
      }
    }
}

GV *
Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
		       const svtype sv_type)
{
    dVAR;
    const char *name = nambeg;
    GV *gv = NULL;
    GV**gvp;
    STRLEN len;
    HV *stash = NULL;
    const I32 no_init = flags & (GV_NOADD_NOINIT | GV_NOINIT);
    const I32 no_expand = flags & GV_NOEXPAND;
    const I32 add = flags & ~GV_NOADD_MASK;
    const U32 is_utf8 = flags & SVf_UTF8;
    bool addmg = cBOOL(flags & GV_ADDMG);
    const char *const name_end = nambeg + full_len;
    U32 faking_it;

    PERL_ARGS_ASSERT_GV_FETCHPVN_FLAGS;

     /* If we have GV_NOTQUAL, the caller promised that
      * there is no stash, so we can skip the check.
      * Similarly if full_len is 0, since then we're
      * dealing with something like *{""} or ""->foo()
      */
    if ((flags & GV_NOTQUAL) || !full_len) {
        len = full_len;
    }
    else if (parse_gv_stash_name(&stash, &gv, &name, &len, nambeg, full_len, is_utf8, add)) {
        if (name == name_end) return gv;
    }
    else {
        return NULL;
    }

    if (!stash && !find_default_stash(&stash, name, len, is_utf8, add, sv_type)) {
        return NULL;
    }
    
    /* By this point we should have a stash and a name */
    gvp = (GV**)hv_fetch(stash,name,is_utf8 ? -(I32)len : (I32)len,add);
    if (!gvp || *gvp == (const GV *)&PL_sv_undef) {
	if (addmg) gv = (GV *)newSV(0);
	else return NULL;
    }
    else gv = *gvp, addmg = 0;
    /* From this point on, addmg means gv has not been inserted in the
       symtab yet. */

    if (SvTYPE(gv) == SVt_PVGV) {
        /* The GV already exists, so return it, but check if we need to do
         * anything else with it before that.
         */
	if (add) {
            /* This is the heuristic that handles if a variable triggers the
             * 'used only once' warning.  If there's already a GV in the stash
             * with this name, then we assume that the variable has been used
             * before and turn its MULTI flag on.
             * It's a heuristic because it can easily be "tricked", like with
             * BEGIN { $a = 1; $::{foo} = *a }; () = $foo
             * not warning about $main::foo being used just once
             */
	    GvMULTI_on(gv);
	    gv_init_svtype(gv, sv_type);
            /* You reach this path once the typeglob has already been created,
               either by the same or a different sigil.  If this path didn't
               exist, then (say) referencing $! first, and %! second would
               mean that %! was not handled correctly.  */
	    if (len == 1 && stash == PL_defstash) {
                maybe_multimagic_gv(gv, name, sv_type);
	    }
	    else if (len == 3 && sv_type == SVt_PVAV
	          && strnEQ(name, "ISA", 3)
	          && (!GvAV(gv) || !SvSMAGICAL(GvAV(gv))))
		gv_magicalize_isa(gv);
	}
	return gv;
    } else if (no_init) {
	assert(!addmg);
	return gv;
    }
    /* If GV_NOEXPAND is true and what we got off the stash is a ref,
     * don't expand it to a glob. This is an optimization so that things
     * copying constants over, like Exporter, don't have to be rewritten
     * to take into account that you can store more than just globs in
     * stashes.
     */
    else if (no_expand && SvROK(gv)) {
	assert(!addmg);
	return gv;
    }

    /* Adding a new symbol.
       Unless of course there was already something non-GV here, in which case
       we want to behave as if there was always a GV here, containing some sort
       of subroutine.
       Otherwise we run the risk of creating things like GvIO, which can cause
       subtle bugs. eg the one that tripped up SQL::Translator  */

    faking_it = SvOK(gv);

    if (add & GV_ADDWARN)
	Perl_ck_warner_d(aTHX_ packWARN(WARN_INTERNAL),
		"Had to create %"UTF8f" unexpectedly",
		 UTF8fARG(is_utf8, name_end-nambeg, nambeg));
    gv_init_pvn(gv, stash, name, len, (add & GV_ADDMULTI)|is_utf8);

    if ( isIDFIRST_lazy_if(name, is_utf8) && !ckWARN(WARN_ONCE) )
        GvMULTI_on(gv) ;

    /* First, store the gv in the symtab if we're adding magic,
     * but only for non-empty GVs
     */
#define GvEMPTY(gv)      !(GvAV(gv) || GvHV(gv) || GvIO(gv) \
                        || GvCV(gv) || (GvSV(gv) && SvOK(GvSV(gv))))
    
    if ( addmg && !GvEMPTY(gv) ) {
        (void)hv_store(stash,name,len,(SV *)gv,0);
    }

    /* set up magic where warranted */
    if ( gv_magicalize(gv, stash, name, len, addmg, sv_type) ) {
        /* See 23496c6 */
        if (GvEMPTY(gv)) {
            if ( GvSV(gv) && SvMAGICAL(GvSV(gv)) ) {
                /* The GV was and still is "empty", except that now
                 * it has the magic flags turned on, so we want it
                 * stored in the symtab.
                 */
                (void)hv_store(stash,name,len,(SV *)gv,0);
            }
            else {
                /* Most likely the temporary GV created above */
                SvREFCNT_dec_NN(gv);
                gv = NULL;
            }
        }
    }
    
    if (gv) gv_init_svtype(gv, faking_it ? SVt_PVCV : sv_type);
    return gv;
}

void
Perl_gv_fullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
{
    const char *name;
    const HV * const hv = GvSTASH(gv);

    PERL_ARGS_ASSERT_GV_FULLNAME4;

    sv_setpv(sv, prefix ? prefix : "");

    if (hv && (name = HvNAME(hv))) {
      const STRLEN len = HvNAMELEN(hv);
      if (keepmain || strnNE(name, "main", len)) {
	sv_catpvn_flags(sv,name,len,HvNAMEUTF8(hv)?SV_CATUTF8:SV_CATBYTES);
	sv_catpvs(sv,"::");
      }
    }
    else sv_catpvs(sv,"__ANON__::");
    sv_catsv(sv,sv_2mortal(newSVhek(GvNAME_HEK(gv))));
}

void
Perl_gv_efullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
{
    const GV * const egv = GvEGVx(gv);

    PERL_ARGS_ASSERT_GV_EFULLNAME4;

    gv_fullname4(sv, egv ? egv : gv, prefix, keepmain);
}


/* recursively scan a stash and any nested stashes looking for entries
 * that need the "only used once" warning raised
 */

void
Perl_gv_check(pTHX_ HV *stash)
{
    dVAR;
    I32 i;

    PERL_ARGS_ASSERT_GV_CHECK;

    if (!HvARRAY(stash))
	return;

    assert(SvOOK(stash));

    for (i = 0; i <= (I32) HvMAX(stash); i++) {
        const HE *entry;
        /* mark stash is being scanned, to avoid recursing */
        HvAUX(stash)->xhv_aux_flags |= HvAUXf_SCAN_STASH;
	for (entry = HvARRAY(stash)[i]; entry; entry = HeNEXT(entry)) {
            GV *gv;
            HV *hv;
	    if (HeKEY(entry)[HeKLEN(entry)-1] == ':' &&
		(gv = MUTABLE_GV(HeVAL(entry))) && isGV(gv) && (hv = GvHV(gv)))
	    {
		if (hv != PL_defstash && hv != stash
                    && !(SvOOK(hv)
                        && (HvAUX(hv)->xhv_aux_flags & HvAUXf_SCAN_STASH))
                )
		     gv_check(hv);              /* nested package */
	    }
            else if ( *HeKEY(entry) != '_'
                        && isIDFIRST_lazy_if(HeKEY(entry), HeUTF8(entry)) ) {
                const char *file;
		gv = MUTABLE_GV(HeVAL(entry));
		if (SvTYPE(gv) != SVt_PVGV || GvMULTI(gv))
		    continue;
		file = GvFILE(gv);
		CopLINE_set(PL_curcop, GvLINE(gv));
#ifdef USE_ITHREADS
		CopFILE(PL_curcop) = (char *)file;	/* set for warning */
#else
		CopFILEGV(PL_curcop)
		    = gv_fetchfile_flags(file, HEK_LEN(GvFILE_HEK(gv)), 0);
#endif
		Perl_warner(aTHX_ packWARN(WARN_ONCE),
			"Name \"%"HEKf"::%"HEKf
			"\" used only once: possible typo",
                            HEKfARG(HvNAME_HEK(stash)),
                            HEKfARG(GvNAME_HEK(gv)));
	    }
	}
        HvAUX(stash)->xhv_aux_flags &= ~HvAUXf_SCAN_STASH;
    }
}

GV *
Perl_newGVgen_flags(pTHX_ const char *pack, U32 flags)
{
    dVAR;
    PERL_ARGS_ASSERT_NEWGVGEN_FLAGS;
    assert(!(flags & ~SVf_UTF8));

    return gv_fetchpv(Perl_form(aTHX_ "%"UTF8f"::_GEN_%ld",
                                UTF8fARG(flags, strlen(pack), pack),
                                (long)PL_gensym++),
                      GV_ADD, SVt_PVGV);
}

/* hopefully this is only called on local symbol table entries */

GP*
Perl_gp_ref(pTHX_ GP *gp)
{
    dVAR;
    if (!gp)
	return NULL;
    gp->gp_refcnt++;
    if (gp->gp_cv) {
	if (gp->gp_cvgen) {
	    /* If the GP they asked for a reference to contains
               a method cache entry, clear it first, so that we
               don't infect them with our cached entry */
	    SvREFCNT_dec_NN(gp->gp_cv);
	    gp->gp_cv = NULL;
	    gp->gp_cvgen = 0;
	}
    }
    return gp;
}

void
Perl_gp_free(pTHX_ GV *gv)
{
    dVAR;
    GP* gp;
    int attempts = 100;

    if (!gv || !isGV_with_GP(gv) || !(gp = GvGP(gv)))
	return;
    if (gp->gp_refcnt == 0) {
	Perl_ck_warner_d(aTHX_ packWARN(WARN_INTERNAL),
			 "Attempt to free unreferenced glob pointers"
			 pTHX__FORMAT pTHX__VALUE);
        return;
    }
    if (gp->gp_refcnt > 1) {
       borrowed:
	if (gp->gp_egv == gv)
	    gp->gp_egv = 0;
	gp->gp_refcnt--;
	GvGP_set(gv, NULL);
        return;
    }

    while (1) {
      /* Copy and null out all the glob slots, so destructors do not see
         freed SVs. */
      HEK * const file_hek = gp->gp_file_hek;
      SV  * const sv       = gp->gp_sv;
      AV  * const av       = gp->gp_av;
      HV  * const hv       = gp->gp_hv;
      IO  * const io       = gp->gp_io;
      CV  * const cv       = gp->gp_cv;
      CV  * const form     = gp->gp_form;

      gp->gp_file_hek = NULL;
      gp->gp_sv       = NULL;
      gp->gp_av       = NULL;
      gp->gp_hv       = NULL;
      gp->gp_io       = NULL;
      gp->gp_cv       = NULL;
      gp->gp_form     = NULL;

      if (file_hek)
	unshare_hek(file_hek);

      SvREFCNT_dec(sv);
      SvREFCNT_dec(av);
      /* FIXME - another reference loop GV -> symtab -> GV ?
         Somehow gp->gp_hv can end up pointing at freed garbage.  */
      if (hv && SvTYPE(hv) == SVt_PVHV) {
        const HEK *hvname_hek = HvNAME_HEK(hv);
        DEBUG_o(Perl_deb(aTHX_ "gp_free clearing PL_stashcache for '%"HEKf"'\n", hvname_hek));
        if (PL_stashcache && hvname_hek)
           (void)hv_deletehek(PL_stashcache, hvname_hek, G_DISCARD);
	SvREFCNT_dec(hv);
      }
      SvREFCNT_dec(io);
      SvREFCNT_dec(cv);
      SvREFCNT_dec(form);

      /* Possibly reallocated by a destructor */
      gp = GvGP(gv);

      if (!gp->gp_file_hek
       && !gp->gp_sv
       && !gp->gp_av
       && !gp->gp_hv
       && !gp->gp_io
       && !gp->gp_cv
       && !gp->gp_form) break;

      if (--attempts == 0) {
	Perl_die(aTHX_
	  "panic: gp_free failed to free glob pointer - "
	  "something is repeatedly re-creating entries"
	);
      }
    }

    /* Possibly incremented by a destructor doing glob assignment */
    if (gp->gp_refcnt > 1) goto borrowed;
    Safefree(gp);
    GvGP_set(gv, NULL);
}

int
Perl_magic_freeovrld(pTHX_ SV *sv, MAGIC *mg)
{
    AMT * const amtp = (AMT*)mg->mg_ptr;
    PERL_UNUSED_ARG(sv);

    PERL_ARGS_ASSERT_MAGIC_FREEOVRLD;

    if (amtp && AMT_AMAGIC(amtp)) {
	int i;
	for (i = 1; i < NofAMmeth; i++) {
	    CV * const cv = amtp->table[i];
	    if (cv) {
		SvREFCNT_dec_NN(MUTABLE_SV(cv));
		amtp->table[i] = NULL;
	    }
	}
    }
 return 0;
}

/* Updates and caches the CV's */
/* Returns:
 * 1 on success and there is some overload
 * 0 if there is no overload
 * -1 if some error occurred and it couldn't croak
 */

int
Perl_Gv_AMupdate(pTHX_ HV *stash, bool destructing)
{
  dVAR;
  MAGIC* const mg = mg_find((const SV *)stash, PERL_MAGIC_overload_table);
  AMT amt;
  const struct mro_meta* stash_meta = HvMROMETA(stash);
  U32 newgen;

  PERL_ARGS_ASSERT_GV_AMUPDATE;

  newgen = PL_sub_generation + stash_meta->pkg_gen + stash_meta->cache_gen;
  if (mg) {
      const AMT * const amtp = (AMT*)mg->mg_ptr;
      if (amtp->was_ok_sub == newgen) {
	  return AMT_AMAGIC(amtp) ? 1 : 0;
      }
      sv_unmagic(MUTABLE_SV(stash), PERL_MAGIC_overload_table);
  }

  DEBUG_o( Perl_deb(aTHX_ "Recalcing overload magic in package %s\n",HvNAME_get(stash)) );

  Zero(&amt,1,AMT);
  amt.was_ok_sub = newgen;
  amt.fallback = AMGfallNO;
  amt.flags = 0;

  {
    int filled = 0;
    int i;
    bool deref_seen = 0;


    /* Work with "fallback" key, which we assume to be first in PL_AMG_names */

    /* Try to find via inheritance. */
    GV *gv = gv_fetchmeth_pvn(stash, PL_AMG_names[0], 2, -1, 0);
    SV * const sv = gv ? GvSV(gv) : NULL;
    CV* cv;

    if (!gv)
    {
      if (!gv_fetchmeth_pvn(stash, "((", 2, -1, 0))
	goto no_table;
    }
#ifdef PERL_DONT_CREATE_GVSV
    else if (!sv) {
	NOOP;   /* Equivalent to !SvTRUE and !SvOK  */
    }
#endif
    else if (SvTRUE(sv))
        /* don't need to set overloading here because fallback => 1
         * is the default setting for classes without overloading */
	amt.fallback=AMGfallYES;
    else if (SvOK(sv)) {
	amt.fallback=AMGfallNEVER;
        filled = 1;
    }
    else {
        filled = 1;
    }

    assert(SvOOK(stash));
    /* initially assume the worst */
    HvAUX(stash)->xhv_aux_flags &= ~HvAUXf_NO_DEREF;

    for (i = 1; i < NofAMmeth; i++) {
	const char * const cooky = PL_AMG_names[i];
	/* Human-readable form, for debugging: */
	const char * const cp = AMG_id2name(i);
	const STRLEN l = PL_AMG_namelens[i];

	DEBUG_o( Perl_deb(aTHX_ "Checking overloading of \"%s\" in package \"%.256s\"\n",
		     cp, HvNAME_get(stash)) );
	/* don't fill the cache while looking up!
	   Creation of inheritance stubs in intermediate packages may
	   conflict with the logic of runtime method substitution.
	   Indeed, for inheritance A -> B -> C, if C overloads "+0",
	   then we could have created stubs for "(+0" in A and C too.
	   But if B overloads "bool", we may want to use it for
	   numifying instead of C's "+0". */
	gv = Perl_gv_fetchmeth_pvn(aTHX_ stash, cooky, l, -1, 0);
        cv = 0;
        if (gv && (cv = GvCV(gv)) && CvGV(cv)) {
	    if(GvNAMELEN(CvGV(cv)) == 3 && strEQ(GvNAME(CvGV(cv)), "nil")){
	      const char * const hvname = HvNAME_get(GvSTASH(CvGV(cv)));
	      if (hvname && HEK_LEN(HvNAME_HEK(GvSTASH(CvGV(cv)))) == 8
	       && strEQ(hvname, "overload")) {
		/* This is a hack to support autoloading..., while
		   knowing *which* methods were declared as overloaded. */
		/* GvSV contains the name of the method. */
		GV *ngv = NULL;
		SV *gvsv = GvSV(gv);

		DEBUG_o( Perl_deb(aTHX_ "Resolving method \"%"SVf256\
			"\" for overloaded \"%s\" in package \"%.256s\"\n",
			     (void*)GvSV(gv), cp, HvNAME(stash)) );
		if (!gvsv || !SvPOK(gvsv)
		    || !(ngv = gv_fetchmethod_sv_flags(stash, gvsv, 0)))
		{
		    /* Can be an import stub (created by "can"). */
		    if (destructing) {
			return -1;
		    }
		    else {
			const SV * const name = (gvsv && SvPOK(gvsv))
                                                    ? gvsv
                                                    : newSVpvs_flags("???", SVs_TEMP);
			/* diag_listed_as: Can't resolve method "%s" overloading "%s" in package "%s" */
			Perl_croak(aTHX_ "%s method \"%"SVf256
				    "\" overloading \"%s\" "\
				    "in package \"%"HEKf256"\"",
				   (GvCVGEN(gv) ? "Stub found while resolving"
				    : "Can't resolve"),
				   SVfARG(name), cp,
                                   HEKfARG(
					HvNAME_HEK(stash)
				   ));
		    }
		}
		cv = GvCV(gv = ngv);
	      }
	    }
	    DEBUG_o( Perl_deb(aTHX_ "Overloading \"%s\" in package \"%.256s\" via \"%.256s::%.256s\"\n",
			 cp, HvNAME_get(stash), HvNAME_get(GvSTASH(CvGV(cv))),
			 GvNAME(CvGV(cv))) );
	    filled = 1;
	} else if (gv) {		/* Autoloaded... */
	    cv = MUTABLE_CV(gv);
	    filled = 1;
	}
	amt.table[i]=MUTABLE_CV(SvREFCNT_inc_simple(cv));

        if (gv) {
            switch (i) {
            case to_sv_amg:
            case to_av_amg:
            case to_hv_amg:
            case to_gv_amg:
            case to_cv_amg:
            case nomethod_amg:
                deref_seen = 1;
                break;
            }
        }
    }
    if (!deref_seen)
        /* none of @{} etc overloaded; we can do $obj->[N] quicker.
         * NB - aux var invalid here, HvARRAY() could have been
         * reallocated since it was assigned to */
        HvAUX(stash)->xhv_aux_flags |= HvAUXf_NO_DEREF;

    if (filled) {
      AMT_AMAGIC_on(&amt);
      sv_magic(MUTABLE_SV(stash), 0, PERL_MAGIC_overload_table,
						(char*)&amt, sizeof(AMT));
      return TRUE;
    }
  }
  /* Here we have no table: */
 no_table:
  AMT_AMAGIC_off(&amt);
  sv_magic(MUTABLE_SV(stash), 0, PERL_MAGIC_overload_table,
						(char*)&amt, sizeof(AMTS));
  return 0;
}


CV*
Perl_gv_handler(pTHX_ HV *stash, I32 id)
{
    dVAR;
    MAGIC *mg;
    AMT *amtp;
    U32 newgen;
    struct mro_meta* stash_meta;

    if (!stash || !HvNAME_get(stash))
        return NULL;

    stash_meta = HvMROMETA(stash);
    newgen = PL_sub_generation + stash_meta->pkg_gen + stash_meta->cache_gen;

    mg = mg_find((const SV *)stash, PERL_MAGIC_overload_table);
    if (!mg) {
      do_update:
	if (Gv_AMupdate(stash, 0) == -1)
	    return NULL;
	mg = mg_find((const SV *)stash, PERL_MAGIC_overload_table);
    }
    assert(mg);
    amtp = (AMT*)mg->mg_ptr;
    if ( amtp->was_ok_sub != newgen )
	goto do_update;
    if (AMT_AMAGIC(amtp)) {
	CV * const ret = amtp->table[id];
	if (ret && isGV(ret)) {		/* Autoloading stab */
	    /* Passing it through may have resulted in a warning
	       "Inherited AUTOLOAD for a non-method deprecated", since
	       our caller is going through a function call, not a method call.
	       So return the CV for AUTOLOAD, setting $AUTOLOAD. */
	    GV * const gv = gv_fetchmethod(stash, PL_AMG_names[id]);

	    if (gv && GvCV(gv))
		return GvCV(gv);
	}
	return ret;
    }

    return NULL;
}


/* Implement tryAMAGICun_MG macro.
   Do get magic, then see if the stack arg is overloaded and if so call it.
   Flags:
	AMGf_set     return the arg using SETs rather than assigning to
		     the targ
	AMGf_numeric apply sv_2num to the stack arg.
*/

bool
Perl_try_amagic_un(pTHX_ int method, int flags) {
    dVAR;
    dSP;
    SV* tmpsv;
    SV* const arg = TOPs;

    SvGETMAGIC(arg);

    if (SvAMAGIC(arg) && (tmpsv = amagic_call(arg, &PL_sv_undef, method,
					      AMGf_noright | AMGf_unary))) {
	if (flags & AMGf_set) {
	    SETs(tmpsv);
	}
	else {
	    dTARGET;
	    if (SvPADMY(TARG)) {
		sv_setsv(TARG, tmpsv);
		SETTARG;
	    }
	    else
		SETs(tmpsv);
	}
	PUTBACK;
	return TRUE;
    }

    if ((flags & AMGf_numeric) && SvROK(arg))
	*sp = sv_2num(arg);
    return FALSE;
}


/* Implement tryAMAGICbin_MG macro.
   Do get magic, then see if the two stack args are overloaded and if so
   call it.
   Flags:
	AMGf_set     return the arg using SETs rather than assigning to
		     the targ
	AMGf_assign  op may be called as mutator (eg +=)
	AMGf_numeric apply sv_2num to the stack arg.
*/

bool
Perl_try_amagic_bin(pTHX_ int method, int flags) {
    dVAR;
    dSP;
    SV* const left = TOPm1s;
    SV* const right = TOPs;

    SvGETMAGIC(left);
    if (left != right)
	SvGETMAGIC(right);

    if (SvAMAGIC(left) || SvAMAGIC(right)) {
	SV * const tmpsv = amagic_call(left, right, method,
		    ((flags & AMGf_assign) && opASSIGN ? AMGf_assign: 0));
	if (tmpsv) {
	    if (flags & AMGf_set) {
		(void)POPs;
		SETs(tmpsv);
	    }
	    else {
		dATARGET;
		(void)POPs;
		if (opASSIGN || SvPADMY(TARG)) {
		    sv_setsv(TARG, tmpsv);
		    SETTARG;
		}
		else
		    SETs(tmpsv);
	    }
	    PUTBACK;
	    return TRUE;
	}
    }
    if(left==right && SvGMAGICAL(left)) {
	SV * const left = sv_newmortal();
	*(sp-1) = left;
	/* Print the uninitialized warning now, so it includes the vari-
	   able name. */
	if (!SvOK(right)) {
	    if (ckWARN(WARN_UNINITIALIZED)) report_uninit(right);
	    sv_setsv_flags(left, &PL_sv_no, 0);
	}
	else sv_setsv_flags(left, right, 0);
	SvGETMAGIC(right);
    }
    if (flags & AMGf_numeric) {
	if (SvROK(TOPm1s))
	    *(sp-1) = sv_2num(TOPm1s);
	if (SvROK(right))
	    *sp     = sv_2num(right);
    }
    return FALSE;
}

SV *
Perl_amagic_deref_call(pTHX_ SV *ref, int method) {
    SV *tmpsv = NULL;
    HV *stash;

    PERL_ARGS_ASSERT_AMAGIC_DEREF_CALL;

    if (!SvAMAGIC(ref))
        return ref;
    /* return quickly if none of the deref ops are overloaded */
    stash = SvSTASH(SvRV(ref));
    assert(SvOOK(stash));
    if (HvAUX(stash)->xhv_aux_flags & HvAUXf_NO_DEREF)
        return ref;

    while ((tmpsv = amagic_call(ref, &PL_sv_undef, method,
				AMGf_noright | AMGf_unary))) { 
	if (!SvROK(tmpsv))
	    Perl_croak(aTHX_ "Overloaded dereference did not return a reference");
	if (tmpsv == ref || SvRV(tmpsv) == SvRV(ref)) {
	    /* Bail out if it returns us the same reference.  */
	    return tmpsv;
	}
	ref = tmpsv;
        if (!SvAMAGIC(ref))
            break;
    }
    return tmpsv ? tmpsv : ref;
}

bool
Perl_amagic_is_enabled(pTHX_ int method)
{
      SV *lex_mask = cop_hints_fetch_pvs(PL_curcop, "overloading", 0);

      assert(PL_curcop->cop_hints & HINT_NO_AMAGIC);

      if ( !lex_mask || !SvOK(lex_mask) )
	  /* overloading lexically disabled */
	  return FALSE;
      else if ( lex_mask && SvPOK(lex_mask) ) {
	  /* we have an entry in the hints hash, check if method has been
	   * masked by overloading.pm */
	  STRLEN len;
	  const int offset = method / 8;
	  const int bit    = method % 8;
	  char *pv = SvPV(lex_mask, len);

	  /* Bit set, so this overloading operator is disabled */
	  if ( (STRLEN)offset < len && pv[offset] & ( 1 << bit ) )
	      return FALSE;
      }
      return TRUE;
}

SV*
Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
{
  dVAR;
  MAGIC *mg;
  CV *cv=NULL;
  CV **cvp=NULL, **ocvp=NULL;
  AMT *amtp=NULL, *oamtp=NULL;
  int off = 0, off1, lr = 0, notfound = 0;
  int postpr = 0, force_cpy = 0;
  int assign = AMGf_assign & flags;
  const int assignshift = assign ? 1 : 0;
  int use_default_op = 0;
  int force_scalar = 0;
#ifdef DEBUGGING
  int fl=0;
#endif
  HV* stash=NULL;

  PERL_ARGS_ASSERT_AMAGIC_CALL;

  if ( PL_curcop->cop_hints & HINT_NO_AMAGIC ) {
      if (!amagic_is_enabled(method)) return NULL;
  }

  if (!(AMGf_noleft & flags) && SvAMAGIC(left)
      && (stash = SvSTASH(SvRV(left))) && Gv_AMG(stash)
      && (mg = mg_find((const SV *)stash, PERL_MAGIC_overload_table))
      && (ocvp = cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
			? (oamtp = amtp = (AMT*)mg->mg_ptr)->table
			: NULL))
      && ((cv = cvp[off=method+assignshift])
	  || (assign && amtp->fallback > AMGfallNEVER && /* fallback to
						          * usual method */
		  (
#ifdef DEBUGGING
		   fl = 1,
#endif
		   cv = cvp[off=method])))) {
    lr = -1;			/* Call method for left argument */
  } else {
    if (cvp && amtp->fallback > AMGfallNEVER && flags & AMGf_unary) {
      int logic;

      /* look for substituted methods */
      /* In all the covered cases we should be called with assign==0. */
	 switch (method) {
	 case inc_amg:
	   force_cpy = 1;
	   if ((cv = cvp[off=add_ass_amg])
	       || ((cv = cvp[off = add_amg]) && (force_cpy = 0, postpr = 1))) {
	     right = &PL_sv_yes; lr = -1; assign = 1;
	   }
	   break;
	 case dec_amg:
	   force_cpy = 1;
	   if ((cv = cvp[off = subtr_ass_amg])
	       || ((cv = cvp[off = subtr_amg]) && (force_cpy = 0, postpr=1))) {
	     right = &PL_sv_yes; lr = -1; assign = 1;
	   }
	   break;
	 case bool__amg:
	   (void)((cv = cvp[off=numer_amg]) || (cv = cvp[off=string_amg]));
	   break;
	 case numer_amg:
	   (void)((cv = cvp[off=string_amg]) || (cv = cvp[off=bool__amg]));
	   break;
	 case string_amg:
	   (void)((cv = cvp[off=numer_amg]) || (cv = cvp[off=bool__amg]));
	   break;
         case not_amg:
           (void)((cv = cvp[off=bool__amg])
                  || (cv = cvp[off=numer_amg])
                  || (cv = cvp[off=string_amg]));
           if (cv)
               postpr = 1;
           break;
	 case copy_amg:
	   {
	     /*
		  * SV* ref causes confusion with the interpreter variable of
		  * the same name
		  */
	     SV* const tmpRef=SvRV(left);
	     if (!SvROK(tmpRef) && SvTYPE(tmpRef) <= SVt_PVMG) {
		/*
		 * Just to be extra cautious.  Maybe in some
		 * additional cases sv_setsv is safe, too.
		 */
		SV* const newref = newSVsv(tmpRef);
		SvOBJECT_on(newref);
		/* No need to do SvAMAGIC_on here, as SvAMAGIC macros
		   delegate to the stash. */
		SvSTASH_set(newref, MUTABLE_HV(SvREFCNT_inc(SvSTASH(tmpRef))));
		return newref;
	     }
	   }
	   break;
	 case abs_amg:
	   if ((cvp[off1=lt_amg] || cvp[off1=ncmp_amg])
	       && ((cv = cvp[off=neg_amg]) || (cv = cvp[off=subtr_amg]))) {
	     SV* const nullsv=sv_2mortal(newSViv(0));
	     if (off1==lt_amg) {
	       SV* const lessp = amagic_call(left,nullsv,
				       lt_amg,AMGf_noright);
	       logic = SvTRUE(lessp);
	     } else {
	       SV* const lessp = amagic_call(left,nullsv,
				       ncmp_amg,AMGf_noright);
	       logic = (SvNV(lessp) < 0);
	     }
	     if (logic) {
	       if (off==subtr_amg) {
		 right = left;
		 left = nullsv;
		 lr = 1;
	       }
	     } else {
	       return left;
	     }
	   }
	   break;
	 case neg_amg:
	   if ((cv = cvp[off=subtr_amg])) {
	     right = left;
	     left = sv_2mortal(newSViv(0));
	     lr = 1;
	   }
	   break;
	 case int_amg:
	 case iter_amg:			/* XXXX Eventually should do to_gv. */
	 case ftest_amg:		/* XXXX Eventually should do to_gv. */
	 case regexp_amg:
	     /* FAIL safe */
	     return NULL;	/* Delegate operation to standard mechanisms. */
	     break;
	 case to_sv_amg:
	 case to_av_amg:
	 case to_hv_amg:
	 case to_gv_amg:
	 case to_cv_amg:
	     /* FAIL safe */
	     return left;	/* Delegate operation to standard mechanisms. */
	     break;
	 default:
	   goto not_found;
	 }
	 if (!cv) goto not_found;
    } else if (!(AMGf_noright & flags) && SvAMAGIC(right)
	       && (stash = SvSTASH(SvRV(right))) && Gv_AMG(stash)
	       && (mg = mg_find((const SV *)stash, PERL_MAGIC_overload_table))
	       && (cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
			  ? (amtp = (AMT*)mg->mg_ptr)->table
			  : NULL))
	       && (cv = cvp[off=method])) { /* Method for right
					     * argument found */
      lr=1;
    } else if (((cvp && amtp->fallback > AMGfallNEVER)
                || (ocvp && oamtp->fallback > AMGfallNEVER))
	       && !(flags & AMGf_unary)) {
				/* We look for substitution for
				 * comparison operations and
				 * concatenation */
      if (method==concat_amg || method==concat_ass_amg
	  || method==repeat_amg || method==repeat_ass_amg) {
	return NULL;		/* Delegate operation to string conversion */
      }
      off = -1;
      switch (method) {
	 case lt_amg:
	 case le_amg:
	 case gt_amg:
	 case ge_amg:
	 case eq_amg:
	 case ne_amg:
             off = ncmp_amg;
             break;
	 case slt_amg:
	 case sle_amg:
	 case sgt_amg:
	 case sge_amg:
	 case seq_amg:
	 case sne_amg:
             off = scmp_amg;
             break;
	 }
      if (off != -1) {
          if (ocvp && (oamtp->fallback > AMGfallNEVER)) {
              cv = ocvp[off];
              lr = -1;
          }
          if (!cv && (cvp && amtp->fallback > AMGfallNEVER)) {
              cv = cvp[off];
              lr = 1;
          }
      }
      if (cv)
          postpr = 1;
      else
          goto not_found;
    } else {
    not_found:			/* No method found, either report or croak */
      switch (method) {
	 case to_sv_amg:
	 case to_av_amg:
	 case to_hv_amg:
	 case to_gv_amg:
	 case to_cv_amg:
	     /* FAIL safe */
	     return left;	/* Delegate operation to standard mechanisms. */
	     break;
      }
      if (ocvp && (cv=ocvp[nomethod_amg])) { /* Call report method */
	notfound = 1; lr = -1;
      } else if (cvp && (cv=cvp[nomethod_amg])) {
	notfound = 1; lr = 1;
      } else if ((use_default_op =
                  (!ocvp || oamtp->fallback >= AMGfallYES)
                  && (!cvp || amtp->fallback >= AMGfallYES))
                 && !DEBUG_o_TEST) {
	/* Skip generating the "no method found" message.  */
	return NULL;
      } else {
	SV *msg;
	if (off==-1) off=method;
	msg = sv_2mortal(Perl_newSVpvf(aTHX_
		      "Operation \"%s\": no method found,%sargument %s%"SVf"%s%"SVf,
 		      AMG_id2name(method + assignshift),
 		      (flags & AMGf_unary ? " " : "\n\tleft "),
 		      SvAMAGIC(left)?
 		        "in overloaded package ":
 		        "has no overloaded magic",
 		      SvAMAGIC(left)?
		        SVfARG(sv_2mortal(newSVhek(HvNAME_HEK(SvSTASH(SvRV(left)))))):
		        SVfARG(&PL_sv_no),
 		      SvAMAGIC(right)?
 		        ",\n\tright argument in overloaded package ":
 		        (flags & AMGf_unary
 			 ? ""
 			 : ",\n\tright argument has no overloaded magic"),
 		      SvAMAGIC(right)?
		        SVfARG(sv_2mortal(newSVhek(HvNAME_HEK(SvSTASH(SvRV(right)))))):
		        SVfARG(&PL_sv_no)));
        if (use_default_op) {
	  DEBUG_o( Perl_deb(aTHX_ "%"SVf, SVfARG(msg)) );
	} else {
	  Perl_croak(aTHX_ "%"SVf, SVfARG(msg));
	}
	return NULL;
      }
      force_cpy = force_cpy || assign;
    }
  }

  switch (method) {
    /* in these cases, we're calling '+' or '-' as a fallback for a ++ or --
     * operation. we need this to return a value, so that it can be assigned
     * later on, in the postpr block (case inc_amg/dec_amg), even if the
     * increment or decrement was itself called in void context */
    case inc_amg:
      if (off == add_amg)
        force_scalar = 1;
      break;
    case dec_amg:
      if (off == subtr_amg)
        force_scalar = 1;
      break;
    /* in these cases, we're calling an assignment variant of an operator
     * (+= rather than +, for instance). regardless of whether it's a
     * fallback or not, it always has to return a value, which will be
     * assigned to the proper variable later */
    case add_amg:
    case subtr_amg:
    case mult_amg:
    case div_amg:
    case modulo_amg:
    case pow_amg:
    case lshift_amg:
    case rshift_amg:
    case repeat_amg:
    case concat_amg:
    case band_amg:
    case bor_amg:
    case bxor_amg:
      if (assign)
        force_scalar = 1;
      break;
    /* the copy constructor always needs to return a value */
    case copy_amg:
      force_scalar = 1;
      break;
    /* because of the way these are implemented (they don't perform the
     * dereferencing themselves, they return a reference that perl then
     * dereferences later), they always have to be in scalar context */
    case to_sv_amg:
    case to_av_amg:
    case to_hv_amg:
    case to_gv_amg:
    case to_cv_amg:
      force_scalar = 1;
      break;
    /* these don't have an op of their own; they're triggered by their parent
     * op, so the context there isn't meaningful ('$a and foo()' in void
     * context still needs to pass scalar context on to $a's bool overload) */
    case bool__amg:
    case numer_amg:
    case string_amg:
      force_scalar = 1;
      break;
  }

#ifdef DEBUGGING
  if (!notfound) {
    DEBUG_o(Perl_deb(aTHX_
		     "Overloaded operator \"%s\"%s%s%s:\n\tmethod%s found%s in package %"SVf"%s\n",
		     AMG_id2name(off),
		     method+assignshift==off? "" :
		     " (initially \"",
		     method+assignshift==off? "" :
		     AMG_id2name(method+assignshift),
		     method+assignshift==off? "" : "\")",
		     flags & AMGf_unary? "" :
		     lr==1 ? " for right argument": " for left argument",
		     flags & AMGf_unary? " for argument" : "",
		     stash ? SVfARG(sv_2mortal(newSVhek(HvNAME_HEK(stash)))) : SVfARG(newSVpvs_flags("null", SVs_TEMP)),
		     fl? ",\n\tassignment variant used": "") );
  }
#endif
    /* Since we use shallow copy during assignment, we need
     * to dublicate the contents, probably calling user-supplied
     * version of copy operator
     */
    /* We need to copy in following cases:
     * a) Assignment form was called.
     * 		assignshift==1,  assign==T, method + 1 == off
     * b) Increment or decrement, called directly.
     * 		assignshift==0,  assign==0, method + 0 == off
     * c) Increment or decrement, translated to assignment add/subtr.
     * 		assignshift==0,  assign==T,
     *		force_cpy == T
     * d) Increment or decrement, translated to nomethod.
     * 		assignshift==0,  assign==0,
     *		force_cpy == T
     * e) Assignment form translated to nomethod.
     * 		assignshift==1,  assign==T, method + 1 != off
     *		force_cpy == T
     */
    /*	off is method, method+assignshift, or a result of opcode substitution.
     *	In the latter case assignshift==0, so only notfound case is important.
     */
  if ( (lr == -1) && ( ( (method + assignshift == off)
	&& (assign || (method == inc_amg) || (method == dec_amg)))
      || force_cpy) )
  {
      /* newSVsv does not behave as advertised, so we copy missing
       * information by hand */
      SV *tmpRef = SvRV(left);
      SV *rv_copy;
      if (SvREFCNT(tmpRef) > 1 && (rv_copy = AMG_CALLunary(left,copy_amg))) {
	  SvRV_set(left, rv_copy);
	  SvSETMAGIC(left);
	  SvREFCNT_dec_NN(tmpRef);  
      }
  }

  {
    dSP;
    BINOP myop;
    SV* res;
    const bool oldcatch = CATCH_GET;
    I32 oldmark, nret;
    int gimme = force_scalar ? G_SCALAR : GIMME_V;

    CATCH_SET(TRUE);
    Zero(&myop, 1, BINOP);
    myop.op_last = (OP *) &myop;
    myop.op_next = NULL;
    myop.op_flags = OPf_STACKED;

    switch (gimme) {
        case G_VOID:
            myop.op_flags |= OPf_WANT_VOID;
            break;
        case G_ARRAY:
            if (flags & AMGf_want_list) {
                myop.op_flags |= OPf_WANT_LIST;
                break;
            }
            /* FALLTHROUGH */
        default:
            myop.op_flags |= OPf_WANT_SCALAR;
            break;
    }

    PUSHSTACKi(PERLSI_OVERLOAD);
    ENTER;
    SAVEOP();
    PL_op = (OP *) &myop;
    if (PERLDB_SUB && PL_curstash != PL_debstash)
	PL_op->op_private |= OPpENTERSUB_DB;
    Perl_pp_pushmark(aTHX);

    EXTEND(SP, notfound + 5);
    PUSHs(lr>0? right: left);
    PUSHs(lr>0? left: right);
    PUSHs( lr > 0 ? &PL_sv_yes : ( assign ? &PL_sv_undef : &PL_sv_no ));
    if (notfound) {
      PUSHs(newSVpvn_flags(AMG_id2name(method + assignshift),
			   AMG_id2namelen(method + assignshift), SVs_TEMP));
    }
    PUSHs(MUTABLE_SV(cv));
    PUTBACK;
    oldmark = TOPMARK;

    if ((PL_op = PL_ppaddr[OP_ENTERSUB](aTHX)))
      CALLRUNOPS(aTHX);
    LEAVE;
    SPAGAIN;
    nret = SP - (PL_stack_base + oldmark);

    switch (gimme) {
        case G_VOID:
            /* returning NULL has another meaning, and we check the context
             * at the call site too, so this can be differentiated from the
             * scalar case */
            res = &PL_sv_undef;
            SP = PL_stack_base + oldmark;
            break;
        case G_ARRAY: {
            if (flags & AMGf_want_list) {
                res = sv_2mortal((SV *)newAV());
                av_extend((AV *)res, nret);
                while (nret--)
                    av_store((AV *)res, nret, POPs);
                break;
            }
            /* FALLTHROUGH */
        }
        default:
            res = POPs;
            break;
    }

    PUTBACK;
    POPSTACK;
    CATCH_SET(oldcatch);

    if (postpr) {
      int ans;
      switch (method) {
      case le_amg:
      case sle_amg:
	ans=SvIV(res)<=0; break;
      case lt_amg:
      case slt_amg:
	ans=SvIV(res)<0; break;
      case ge_amg:
      case sge_amg:
	ans=SvIV(res)>=0; break;
      case gt_amg:
      case sgt_amg:
	ans=SvIV(res)>0; break;
      case eq_amg:
      case seq_amg:
	ans=SvIV(res)==0; break;
      case ne_amg:
      case sne_amg:
	ans=SvIV(res)!=0; break;
      case inc_amg:
      case dec_amg:
	SvSetSV(left,res); return left;
      case not_amg:
	ans=!SvTRUE(res); break;
      default:
        ans=0; break;
      }
      return boolSV(ans);
    } else if (method==copy_amg) {
      if (!SvROK(res)) {
	Perl_croak(aTHX_ "Copy method did not return a reference");
      }
      return SvREFCNT_inc(SvRV(res));
    } else {
      return res;
    }
  }
}

void
Perl_gv_name_set(pTHX_ GV *gv, const char *name, U32 len, U32 flags)
{
    dVAR;
    U32 hash;

    PERL_ARGS_ASSERT_GV_NAME_SET;

    if (len > I32_MAX)
	Perl_croak(aTHX_ "panic: gv name too long (%"UVuf")", (UV) len);

    if (!(flags & GV_ADD) && GvNAME_HEK(gv)) {
	unshare_hek(GvNAME_HEK(gv));
    }

    PERL_HASH(hash, name, len);
    GvNAME_HEK(gv) = share_hek(name, (flags & SVf_UTF8 ? -(I32)len : (I32)len), hash);
}

/*
=for apidoc gv_try_downgrade

If the typeglob C<gv> can be expressed more succinctly, by having
something other than a real GV in its place in the stash, replace it
with the optimised form.  Basic requirements for this are that C<gv>
is a real typeglob, is sufficiently ordinary, and is only referenced
from its package.  This function is meant to be used when a GV has been
looked up in part to see what was there, causing upgrading, but based
on what was found it turns out that the real GV isn't required after all.

If C<gv> is a completely empty typeglob, it is deleted from the stash.

If C<gv> is a typeglob containing only a sufficiently-ordinary constant
sub, the typeglob is replaced with a scalar-reference placeholder that
more compactly represents the same thing.

=cut
*/

void
Perl_gv_try_downgrade(pTHX_ GV *gv)
{
    HV *stash;
    CV *cv;
    HEK *namehek;
    SV **gvp;
    PERL_ARGS_ASSERT_GV_TRY_DOWNGRADE;

    /* XXX Why and where does this leave dangling pointers during global
       destruction? */
    if (PL_phase == PERL_PHASE_DESTRUCT) return;

    if (!(SvREFCNT(gv) == 1 && SvTYPE(gv) == SVt_PVGV && !SvFAKE(gv) &&
	    !SvOBJECT(gv) && !SvREADONLY(gv) &&
	    isGV_with_GP(gv) && GvGP(gv) &&
	    !GvINTRO(gv) && GvREFCNT(gv) == 1 &&
	    !GvSV(gv) && !GvAV(gv) && !GvHV(gv) && !GvIOp(gv) && !GvFORM(gv) &&
	    GvEGVx(gv) == gv && (stash = GvSTASH(gv))))
	return;
    if (gv == PL_statgv || gv == PL_last_in_gv || gv == PL_stderrgv)
	return;
    if (SvMAGICAL(gv)) {
        MAGIC *mg;
	/* only backref magic is allowed */
	if (SvGMAGICAL(gv) || SvSMAGICAL(gv))
	    return;
        for (mg = SvMAGIC(gv); mg; mg = mg->mg_moremagic) {
            if (mg->mg_type != PERL_MAGIC_backref)
                return;
	}
    }
    cv = GvCV(gv);
    if (!cv) {
	HEK *gvnhek = GvNAME_HEK(gv);
	(void)hv_deletehek(stash, gvnhek, G_DISCARD);
    } else if (GvMULTI(gv) && cv && SvREFCNT(cv) == 1 &&
	    !SvOBJECT(cv) && !SvMAGICAL(cv) && !SvREADONLY(cv) &&
	    CvSTASH(cv) == stash && CvGV(cv) == gv &&
	    CvCONST(cv) && !CvMETHOD(cv) && !CvLVALUE(cv) && !CvUNIQUE(cv) &&
	    !CvNODEBUG(cv) && !CvCLONE(cv) && !CvCLONED(cv) && !CvANON(cv) &&
	    (namehek = GvNAME_HEK(gv)) &&
	    (gvp = hv_fetchhek(stash, namehek, 0)) &&
	    *gvp == (SV*)gv) {
	SV *value = SvREFCNT_inc(CvXSUBANY(cv).any_ptr);
	const bool imported = !!GvIMPORTED_CV(gv);
	SvREFCNT(gv) = 0;
	sv_clear((SV*)gv);
	SvREFCNT(gv) = 1;
	SvFLAGS(gv) = SVt_IV|SVf_ROK|SVprv_PCS_IMPORTED * imported;
	SvANY(gv) = (XPVGV*)((char*)&(gv->sv_u.svu_iv) -
				STRUCT_OFFSET(XPVIV, xiv_iv));
	SvRV_set(gv, value);
    }
}

GV *
Perl_gv_override(pTHX_ const char * const name, const STRLEN len)
{
    GV *gv = gv_fetchpvn(name, len, GV_NOTQUAL, SVt_PVCV);
    GV * const *gvp;
    PERL_ARGS_ASSERT_GV_OVERRIDE;
    if (gv && GvCVu(gv) && GvIMPORTED_CV(gv)) return gv;
    gvp = (GV**)hv_fetch(PL_globalstash, name, len, FALSE);
    gv = gvp ? *gvp : NULL;
    if (gv && !isGV(gv)) {
	if (!SvPCS_IMPORTED(gv)) return NULL;
	gv_init(gv, PL_globalstash, name, len, 0);
	return gv;
    }
    return gv && GvCVu(gv) && GvIMPORTED_CV(gv) ? gv : NULL;
}

#include "XSUB.h"

static void
core_xsub(pTHX_ CV* cv)
{
    Perl_croak(aTHX_
       "&CORE::%s cannot be called directly", GvNAME(CvGV(cv))
    );
}

/*
 * Local variables:
 * c-indentation-style: bsd
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 et:
 */