aboutsummaryrefslogtreecommitdiff
path: root/gold/object.h
blob: dc089f5a417a5c5634b09a796d994459b59c3349 (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
// object.h -- support for an object file for linking in gold  -*- C++ -*-

// Copyright (C) 2006-2021 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#ifndef GOLD_OBJECT_H
#define GOLD_OBJECT_H

#include <string>
#include <vector>

#include "elfcpp.h"
#include "elfcpp_file.h"
#include "fileread.h"
#include "target.h"
#include "archive.h"

namespace gold
{

class General_options;
class Task;
class Cref;
class Layout;
class Kept_section;
class Output_data;
class Output_section;
class Output_section_data;
class Output_file;
class Output_symtab_xindex;
class Pluginobj;
class Dynobj;
class Object_merge_map;
class Relocatable_relocs;
struct Symbols_data;

template<typename Stringpool_char>
class Stringpool_template;

// Data to pass from read_symbols() to add_symbols().

struct Read_symbols_data
{
  Read_symbols_data()
    : section_headers(NULL), section_names(NULL), symbols(NULL),
      symbol_names(NULL), versym(NULL), verdef(NULL), verneed(NULL)
  { }

  ~Read_symbols_data();

  // Section headers.
  File_view* section_headers;
  // Section names.
  File_view* section_names;
  // Size of section name data in bytes.
  section_size_type section_names_size;
  // Symbol data.
  File_view* symbols;
  // Size of symbol data in bytes.
  section_size_type symbols_size;
  // Offset of external symbols within symbol data.  This structure
  // sometimes contains only external symbols, in which case this will
  // be zero.  Sometimes it contains all symbols.
  section_offset_type external_symbols_offset;
  // Symbol names.
  File_view* symbol_names;
  // Size of symbol name data in bytes.
  section_size_type symbol_names_size;

  // Version information.  This is only used on dynamic objects.
  // Version symbol data (from SHT_GNU_versym section).
  File_view* versym;
  section_size_type versym_size;
  // Version definition data (from SHT_GNU_verdef section).
  File_view* verdef;
  section_size_type verdef_size;
  unsigned int verdef_info;
  // Needed version data  (from SHT_GNU_verneed section).
  File_view* verneed;
  section_size_type verneed_size;
  unsigned int verneed_info;
};

// Information used to print error messages.

struct Symbol_location_info
{
  std::string source_file;
  std::string enclosing_symbol_name;
  elfcpp::STT enclosing_symbol_type;
};

// Data about a single relocation section.  This is read in
// read_relocs and processed in scan_relocs.

struct Section_relocs
{
  Section_relocs()
    : contents(NULL)
  { }

  ~Section_relocs()
  { delete this->contents; }

  // Index of reloc section.
  unsigned int reloc_shndx;
  // Index of section that relocs apply to.
  unsigned int data_shndx;
  // Contents of reloc section.
  File_view* contents;
  // Reloc section type.
  unsigned int sh_type;
  // Number of reloc entries.
  size_t reloc_count;
  // Output section.
  Output_section* output_section;
  // Whether this section has special handling for offsets.
  bool needs_special_offset_handling;
  // Whether the data section is allocated (has the SHF_ALLOC flag set).
  bool is_data_section_allocated;
};

// Relocations in an object file.  This is read in read_relocs and
// processed in scan_relocs.

struct Read_relocs_data
{
  Read_relocs_data()
    : local_symbols(NULL)
  { }

  ~Read_relocs_data()
  { delete this->local_symbols; }

  typedef std::vector<Section_relocs> Relocs_list;
  // The relocations.
  Relocs_list relocs;
  // The local symbols.
  File_view* local_symbols;
};

// The Xindex class manages section indexes for objects with more than
// 0xff00 sections.

class Xindex
{
 public:
  Xindex(int large_shndx_offset)
    : large_shndx_offset_(large_shndx_offset), symtab_xindex_()
  { }

  // Initialize the symtab_xindex_ array, given the object and the
  // section index of the symbol table to use.
  template<int size, bool big_endian>
  void
  initialize_symtab_xindex(Object*, unsigned int symtab_shndx);

  // Read in the symtab_xindex_ array, given its section index.
  // PSHDRS may optionally point to the section headers.
  template<int size, bool big_endian>
  void
  read_symtab_xindex(Object*, unsigned int xindex_shndx,
		     const unsigned char* pshdrs);

  // Symbol SYMNDX in OBJECT has a section of SHN_XINDEX; return the
  // real section index.
  unsigned int
  sym_xindex_to_shndx(Object* object, unsigned int symndx);

 private:
  // The type of the array giving the real section index for symbols
  // whose st_shndx field holds SHN_XINDEX.
  typedef std::vector<unsigned int> Symtab_xindex;

  // Adjust a section index if necessary.  This should only be called
  // for ordinary section indexes.
  unsigned int
  adjust_shndx(unsigned int shndx)
  {
    if (shndx >= elfcpp::SHN_LORESERVE)
      shndx += this->large_shndx_offset_;
    return shndx;
  }

  // Adjust to apply to large section indexes.
  int large_shndx_offset_;
  // The data from the SHT_SYMTAB_SHNDX section.
  Symtab_xindex symtab_xindex_;
};

// A GOT offset list.  A symbol may have more than one GOT offset
// (e.g., when mixing modules compiled with two different TLS models),
// but will usually have at most one.  GOT_TYPE identifies the type of
// GOT entry; its values are specific to each target.

class Got_offset_list
{
 public:
  Got_offset_list()
    : got_type_(-1U), got_offset_(0), addend_(0), got_next_(NULL)
  { }

  Got_offset_list(unsigned int got_type, unsigned int got_offset,
		  uint64_t addend)
    : got_type_(got_type), got_offset_(got_offset), addend_(addend),
      got_next_(NULL)
  { }

  ~Got_offset_list()
  {
    if (this->got_next_ != NULL)
      {
        delete this->got_next_;
        this->got_next_ = NULL;
      }
  }

  // Initialize the fields to their default values.
  void
  init()
  {
    this->got_type_ = -1U;
    this->got_offset_ = 0;
    this->addend_ = 0;
    this->got_next_ = NULL;
  }

  // Set the offset for the GOT entry of type GOT_TYPE.
  void
  set_offset(unsigned int got_type, unsigned int got_offset, uint64_t addend)
  {
    if (this->got_type_ == -1U)
      {
        this->got_type_ = got_type;
        this->got_offset_ = got_offset;
        this->addend_ = addend;
      }
    else
      {
        for (Got_offset_list* g = this; g != NULL; g = g->got_next_)
          {
            if (g->got_type_ == got_type && g->addend_ == addend)
              {
                g->got_offset_ = got_offset;
                return;
              }
          }
        Got_offset_list* g = new Got_offset_list(got_type, got_offset, addend);
        g->got_next_ = this->got_next_;
        this->got_next_ = g;
      }
  }

  // Return the offset for a GOT entry of type GOT_TYPE.
  unsigned int
  get_offset(unsigned int got_type, uint64_t addend) const
  {
    for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
      {
        if (g->got_type_ == got_type && g->addend_ == addend)
          return g->got_offset_;
      }
    return -1U;
  }

  // Return a pointer to the list, or NULL if the list is empty.
  const Got_offset_list*
  get_list() const
  {
    if (this->got_type_ == -1U)
      return NULL;
    return this;
  }

  // Abstract visitor class for iterating over GOT offsets.
  class Visitor
  {
   public:
    Visitor()
    { }

    virtual
    ~Visitor()
    { }

    virtual void
    visit(unsigned int, unsigned int, uint64_t) = 0;
  };

  // Loop over all GOT offset entries, calling a visitor class V for each.
  void
  for_all_got_offsets(Visitor* v) const
  {
    if (this->got_type_ == -1U)
      return;
    for (const Got_offset_list* g = this; g != NULL; g = g->got_next_)
      v->visit(g->got_type_, g->got_offset_, g->addend_);
  }

 private:
  unsigned int got_type_;
  unsigned int got_offset_;
  uint64_t addend_;
  Got_offset_list* got_next_;
};

// The Local_got_entry_key used to index the GOT offsets for local
// non-TLS symbols, and tp-relative offsets for TLS symbols.

class Local_got_entry_key
{
 public:
  Local_got_entry_key(unsigned int symndx)
    : symndx_(symndx)
  {}

  // Whether this equals to another Local_got_entry_key.
  bool
  eq(const Local_got_entry_key& key) const
  {
    return this->symndx_ == key.symndx_;
  }

  // Compute a hash value for this using 64-bit FNV-1a hash.
  size_t
  hash_value() const
  {
    uint64_t h = 14695981039346656037ULL; // FNV offset basis.
    uint64_t prime = 1099511628211ULL;
    h = (h ^ static_cast<uint64_t>(this->symndx_)) * prime;
    return h;
  }

  // Functors for associative containers.
  struct equal_to
  {
    bool
    operator()(const Local_got_entry_key& key1,
               const Local_got_entry_key& key2) const
    { return key1.eq(key2); }
  };

  struct hash
  {
    size_t
    operator()(const Local_got_entry_key& key) const
    { return key.hash_value(); }
  };

 private:
  // The local symbol index.
  unsigned int symndx_;
};

// Type for mapping section index to uncompressed size and contents.

struct Compressed_section_info
{
  section_size_type size;
  elfcpp::Elf_Xword flag;
  uint64_t addralign;
  const unsigned char* contents;
};
typedef std::map<unsigned int, Compressed_section_info> Compressed_section_map;

template<int size, bool big_endian>
Compressed_section_map*
build_compressed_section_map(const unsigned char* pshdrs, unsigned int shnum,
			     const char* names, section_size_type names_size,
			     Object* obj, bool decompress_if_needed);

// Osabi represents the EI_OSABI field from the ELF header.

class Osabi
{
 public:
  Osabi(unsigned char ei_osabi)
    : ei_osabi_(static_cast<elfcpp::ELFOSABI>(ei_osabi))
  { }

  bool
  has_shf_retain(elfcpp::Elf_Xword sh_flags) const
  {
    switch (this->ei_osabi_)
      {
      case elfcpp::ELFOSABI_GNU:
      case elfcpp::ELFOSABI_FREEBSD:
	return (sh_flags & elfcpp::SHF_GNU_RETAIN) != 0;
      default:
        break;
      }
    return false;
  }

  elfcpp::Elf_Xword
  ignored_sh_flags() const
  {
    switch (this->ei_osabi_)
      {
      case elfcpp::ELFOSABI_GNU:
      case elfcpp::ELFOSABI_FREEBSD:
	return elfcpp::SHF_GNU_RETAIN;
      default:
        break;
      }
    return 0;
  }

 private:
  elfcpp::ELFOSABI ei_osabi_;
};

// Object is an abstract base class which represents either a 32-bit
// or a 64-bit input object.  This can be a regular object file
// (ET_REL) or a shared object (ET_DYN).

class Object
{
 public:
  typedef std::vector<Symbol*> Symbols;

  // NAME is the name of the object as we would report it to the user
  // (e.g., libfoo.a(bar.o) if this is in an archive.  INPUT_FILE is
  // used to read the file.  OFFSET is the offset within the input
  // file--0 for a .o or .so file, something else for a .a file.
  Object(const std::string& name, Input_file* input_file, bool is_dynamic,
	 off_t offset = 0)
    : name_(name), input_file_(input_file), offset_(offset), shnum_(-1U),
      is_dynamic_(is_dynamic), is_needed_(false), uses_split_stack_(false),
      has_no_split_stack_(false), no_export_(false),
      is_in_system_directory_(false), as_needed_(false), xindex_(NULL),
      compressed_sections_(NULL)
  {
    if (input_file != NULL)
      {
	input_file->file().add_object();
	this->is_in_system_directory_ = input_file->is_in_system_directory();
	this->as_needed_ = input_file->options().as_needed();
      }
  }

  virtual ~Object()
  {
    if (this->input_file_ != NULL)
      this->input_file_->file().remove_object();
  }

  // Return the name of the object as we would report it to the user.
  const std::string&
  name() const
  { return this->name_; }

  // Get the offset into the file.
  off_t
  offset() const
  { return this->offset_; }

  // Return whether this is a dynamic object.
  bool
  is_dynamic() const
  { return this->is_dynamic_; }

  // Return the word size of the object file.
  virtual int elfsize() const = 0;

  // Return TRUE if this is a big-endian object file.
  virtual bool is_big_endian() const = 0;

  // Return whether this object is needed--true if it is a dynamic
  // object which defines some symbol referenced by a regular object.
  // We keep the flag here rather than in Dynobj for convenience when
  // setting it.
  bool
  is_needed() const
  { return this->is_needed_; }

  // Record that this object is needed.
  void
  set_is_needed()
  { this->is_needed_ = true; }

  // Return whether this object was compiled with -fsplit-stack.
  bool
  uses_split_stack() const
  { return this->uses_split_stack_; }

  // Return whether this object contains any functions compiled with
  // the no_split_stack attribute.
  bool
  has_no_split_stack() const
  { return this->has_no_split_stack_; }

  // Returns NULL for Objects that are not dynamic objects.  This method
  // is overridden in the Dynobj class.
  Dynobj*
  dynobj()
  { return this->do_dynobj(); }

  // Returns NULL for Objects that are not plugin objects.  This method
  // is overridden in the Pluginobj class.
  Pluginobj*
  pluginobj()
  { return this->do_pluginobj(); }

  // Get the file.  We pass on const-ness.
  Input_file*
  input_file()
  {
    gold_assert(this->input_file_ != NULL);
    return this->input_file_;
  }

  const Input_file*
  input_file() const
  {
    gold_assert(this->input_file_ != NULL);
    return this->input_file_;
  }

  // Lock the underlying file.
  void
  lock(const Task* t)
  {
    if (this->input_file_ != NULL)
      this->input_file_->file().lock(t);
  }

  // Unlock the underlying file.
  void
  unlock(const Task* t)
  {
    if (this->input_file_ != NULL)
      this->input_file()->file().unlock(t);
  }

  // Return whether the underlying file is locked.
  bool
  is_locked() const
  { return this->input_file_ != NULL && this->input_file_->file().is_locked(); }

  // Return the token, so that the task can be queued.
  Task_token*
  token()
  {
    if (this->input_file_ == NULL)
      return NULL;
    return this->input_file()->file().token();
  }

  // Release the underlying file.
  void
  release()
  {
    if (this->input_file_ != NULL)
      this->input_file()->file().release();
  }

  // Return whether we should just read symbols from this file.
  bool
  just_symbols() const
  { return this->input_file()->just_symbols(); }

  // Return whether this is an incremental object.
  bool
  is_incremental() const
  { return this->do_is_incremental(); }

  // Return the last modified time of the file.
  Timespec
  get_mtime()
  { return this->do_get_mtime(); }

  // Get the number of sections.
  unsigned int
  shnum() const
  { return this->shnum_; }

  // Return a view of the contents of a section.  Set *PLEN to the
  // size.  CACHE is a hint as in File_read::get_view.
  const unsigned char*
  section_contents(unsigned int shndx, section_size_type* plen, bool cache);

  // Adjust a symbol's section index as needed.  SYMNDX is the index
  // of the symbol and SHNDX is the symbol's section from
  // get_st_shndx.  This returns the section index.  It sets
  // *IS_ORDINARY to indicate whether this is a normal section index,
  // rather than a special code between SHN_LORESERVE and
  // SHN_HIRESERVE.
  unsigned int
  adjust_sym_shndx(unsigned int symndx, unsigned int shndx, bool* is_ordinary)
  {
    if (shndx < elfcpp::SHN_LORESERVE)
      *is_ordinary = true;
    else if (shndx == elfcpp::SHN_XINDEX)
      {
	if (this->xindex_ == NULL)
	  this->xindex_ = this->do_initialize_xindex();
	shndx = this->xindex_->sym_xindex_to_shndx(this, symndx);
	*is_ordinary = true;
      }
    else
      *is_ordinary = false;
    return shndx;
  }

  // Return the size of a section given a section index.
  uint64_t
  section_size(unsigned int shndx)
  { return this->do_section_size(shndx); }

  // Return the name of a section given a section index.
  std::string
  section_name(unsigned int shndx) const
  { return this->do_section_name(shndx); }

  // Return the section flags given a section index.
  uint64_t
  section_flags(unsigned int shndx)
  { return this->do_section_flags(shndx); }

  // Return the section entsize given a section index.
  uint64_t
  section_entsize(unsigned int shndx)
  { return this->do_section_entsize(shndx); }

  // Return the section address given a section index.
  uint64_t
  section_address(unsigned int shndx)
  { return this->do_section_address(shndx); }

  // Return the section type given a section index.
  unsigned int
  section_type(unsigned int shndx)
  { return this->do_section_type(shndx); }

  // Return the section link field given a section index.
  unsigned int
  section_link(unsigned int shndx)
  { return this->do_section_link(shndx); }

  // Return the section info field given a section index.
  unsigned int
  section_info(unsigned int shndx)
  { return this->do_section_info(shndx); }

  // Return the required section alignment given a section index.
  uint64_t
  section_addralign(unsigned int shndx)
  { return this->do_section_addralign(shndx); }

  // Return the output section given a section index.
  Output_section*
  output_section(unsigned int shndx) const
  { return this->do_output_section(shndx); }

  // Given a section index, return its address.
  // The return value will be -1U if the section is specially mapped,
  // such as a merge section.
  uint64_t
  output_section_address(unsigned int shndx)
  { return this->do_output_section_address(shndx); }

  // Given a section index, return the offset in the Output_section.
  // The return value will be -1U if the section is specially mapped,
  // such as a merge section.
  uint64_t
  output_section_offset(unsigned int shndx) const
  { return this->do_output_section_offset(shndx); }

  // Read the symbol information.
  void
  read_symbols(Read_symbols_data* sd)
  { return this->do_read_symbols(sd); }

  // Pass sections which should be included in the link to the Layout
  // object, and record where the sections go in the output file.
  void
  layout(Symbol_table* symtab, Layout* layout, Read_symbols_data* sd)
  { this->do_layout(symtab, layout, sd); }

  // Add symbol information to the global symbol table.
  void
  add_symbols(Symbol_table* symtab, Read_symbols_data* sd, Layout *layout)
  { this->do_add_symbols(symtab, sd, layout); }

  // Add symbol information to the global symbol table.
  Archive::Should_include
  should_include_member(Symbol_table* symtab, Layout* layout,
			Read_symbols_data* sd, std::string* why)
  { return this->do_should_include_member(symtab, layout, sd, why); }

  // Iterate over global symbols, calling a visitor class V for each.
  void
  for_all_global_symbols(Read_symbols_data* sd,
			 Library_base::Symbol_visitor_base* v)
  { return this->do_for_all_global_symbols(sd, v); }

  // Iterate over local symbols, calling a visitor class V for each GOT offset
  // associated with a local symbol.
  void
  for_all_local_got_entries(Got_offset_list::Visitor* v) const
  { this->do_for_all_local_got_entries(v); }

  // Functions and types for the elfcpp::Elf_file interface.  This
  // permit us to use Object as the File template parameter for
  // elfcpp::Elf_file.

  // The View class is returned by view.  It must support a single
  // method, data().  This is trivial, because get_view does what we
  // need.
  class View
  {
   public:
    View(const unsigned char* p)
      : p_(p)
    { }

    const unsigned char*
    data() const
    { return this->p_; }

   private:
    const unsigned char* p_;
  };

  // Return a View.
  View
  view(off_t file_offset, section_size_type data_size)
  { return View(this->get_view(file_offset, data_size, true, true)); }

  // Report an error.
  void
  error(const char* format, ...) const ATTRIBUTE_PRINTF_2;

  // A location in the file.
  struct Location
  {
    off_t file_offset;
    off_t data_size;

    Location(off_t fo, section_size_type ds)
      : file_offset(fo), data_size(ds)
    { }
  };

  // Get a View given a Location.
  View view(Location loc)
  { return View(this->get_view(loc.file_offset, loc.data_size, true, true)); }

  // Get a view into the underlying file.
  const unsigned char*
  get_view(off_t start, section_size_type size, bool aligned, bool cache)
  {
    return this->input_file()->file().get_view(this->offset_, start, size,
					       aligned, cache);
  }

  // Get a lasting view into the underlying file.
  File_view*
  get_lasting_view(off_t start, section_size_type size, bool aligned,
		   bool cache)
  {
    return this->input_file()->file().get_lasting_view(this->offset_, start,
						       size, aligned, cache);
  }

  // Read data from the underlying file.
  void
  read(off_t start, section_size_type size, void* p)
  { this->input_file()->file().read(start + this->offset_, size, p); }

  // Read multiple data from the underlying file.
  void
  read_multiple(const File_read::Read_multiple& rm)
  { this->input_file()->file().read_multiple(this->offset_, rm); }

  // Stop caching views in the underlying file.
  void
  clear_view_cache_marks()
  {
    if (this->input_file_ != NULL)
      this->input_file_->file().clear_view_cache_marks();
  }

  // Get the number of global symbols defined by this object, and the
  // number of the symbols whose final definition came from this
  // object.
  void
  get_global_symbol_counts(const Symbol_table* symtab, size_t* defined,
			   size_t* used) const
  { this->do_get_global_symbol_counts(symtab, defined, used); }

  // Get the symbols defined in this object.
  const Symbols*
  get_global_symbols() const
  { return this->do_get_global_symbols(); }

  // Set flag that this object was found in a system directory.
  void
  set_is_in_system_directory()
  { this->is_in_system_directory_ = true; }

  // Return whether this object was found in a system directory.
  bool
  is_in_system_directory() const
  { return this->is_in_system_directory_; }

  // Set flag that this object was linked with --as-needed.
  void
  set_as_needed()
  { this->as_needed_ = true; }

  // Clear flag that this object was linked with --as-needed.
  void
  clear_as_needed()
  { this->as_needed_ = false; }

  // Return whether this object was linked with --as-needed.
  bool
  as_needed() const
  { return this->as_needed_; }

  // Return whether we found this object by searching a directory.
  bool
  searched_for() const
  { return this->input_file()->will_search_for(); }

  bool
  no_export() const
  { return this->no_export_; }

  void
  set_no_export(bool value)
  { this->no_export_ = value; }

  bool
  section_is_compressed(unsigned int shndx,
			section_size_type* uncompressed_size,
			elfcpp::Elf_Xword* palign = NULL) const
  {
    if (this->compressed_sections_ == NULL)
      return false;
    Compressed_section_map::const_iterator p =
        this->compressed_sections_->find(shndx);
    if (p != this->compressed_sections_->end())
      {
	if (uncompressed_size != NULL)
	  *uncompressed_size = p->second.size;
	if (palign != NULL)
	  *palign = p->second.addralign;
	return true;
      }
    return false;
  }

  // Return a view of the decompressed contents of a section.  Set *PLEN
  // to the size.  Set *IS_NEW to true if the contents need to be freed
  // by the caller.
  const unsigned char*
  decompressed_section_contents(unsigned int shndx, section_size_type* plen,
				bool* is_cached, uint64_t* palign = NULL);

  // Discard any buffers of decompressed sections.  This is done
  // at the end of the Add_symbols task.
  void
  discard_decompressed_sections();

  // Return the index of the first incremental relocation for symbol SYMNDX.
  unsigned int
  get_incremental_reloc_base(unsigned int symndx) const
  { return this->do_get_incremental_reloc_base(symndx); }

  // Return the number of incremental relocations for symbol SYMNDX.
  unsigned int
  get_incremental_reloc_count(unsigned int symndx) const
  { return this->do_get_incremental_reloc_count(symndx); }

  // Return the output view for section SHNDX.
  unsigned char*
  get_output_view(unsigned int shndx, section_size_type* plen) const
  { return this->do_get_output_view(shndx, plen); }

 protected:
  // Returns NULL for Objects that are not dynamic objects.  This method
  // is overridden in the Dynobj class.
  virtual Dynobj*
  do_dynobj()
  { return NULL; }

  // Returns NULL for Objects that are not plugin objects.  This method
  // is overridden in the Pluginobj class.
  virtual Pluginobj*
  do_pluginobj()
  { return NULL; }

  // Return TRUE if this is an incremental (unchanged) input file.
  // We return FALSE by default; the incremental object classes
  // override this method.
  virtual bool
  do_is_incremental() const
  { return false; }

  // Return the last modified time of the file.  This method may be
  // overridden for subclasses that don't use an actual file (e.g.,
  // Incremental objects).
  virtual Timespec
  do_get_mtime()
  { return this->input_file()->file().get_mtime(); }

  // Read the symbols--implemented by child class.
  virtual void
  do_read_symbols(Read_symbols_data*) = 0;

  // Lay out sections--implemented by child class.
  virtual void
  do_layout(Symbol_table*, Layout*, Read_symbols_data*) = 0;

  // Add symbol information to the global symbol table--implemented by
  // child class.
  virtual void
  do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*) = 0;

  virtual Archive::Should_include
  do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
                           std::string* why) = 0;

  // Iterate over global symbols, calling a visitor class V for each.
  virtual void
  do_for_all_global_symbols(Read_symbols_data* sd,
			    Library_base::Symbol_visitor_base* v) = 0;

  // Iterate over local symbols, calling a visitor class V for each GOT offset
  // associated with a local symbol.
  virtual void
  do_for_all_local_got_entries(Got_offset_list::Visitor* v) const = 0;

  // Return the location of the contents of a section.  Implemented by
  // child class.
  virtual const unsigned char*
  do_section_contents(unsigned int shndx, section_size_type* plen,
		      bool cache) = 0;

  // Get the size of a section--implemented by child class.
  virtual uint64_t
  do_section_size(unsigned int shndx) = 0;

  // Get the name of a section--implemented by child class.
  virtual std::string
  do_section_name(unsigned int shndx) const = 0;

  // Get section flags--implemented by child class.
  virtual uint64_t
  do_section_flags(unsigned int shndx) = 0;

  // Get section entsize--implemented by child class.
  virtual uint64_t
  do_section_entsize(unsigned int shndx) = 0;

  // Get section address--implemented by child class.
  virtual uint64_t
  do_section_address(unsigned int shndx) = 0;

  // Get section type--implemented by child class.
  virtual unsigned int
  do_section_type(unsigned int shndx) = 0;

  // Get section link field--implemented by child class.
  virtual unsigned int
  do_section_link(unsigned int shndx) = 0;

  // Get section info field--implemented by child class.
  virtual unsigned int
  do_section_info(unsigned int shndx) = 0;

  // Get section alignment--implemented by child class.
  virtual uint64_t
  do_section_addralign(unsigned int shndx) = 0;

  // Return the output section given a section index--implemented
  // by child class.
  virtual Output_section*
  do_output_section(unsigned int) const
  { gold_unreachable(); }

  // Get the address of a section--implemented by child class.
  virtual uint64_t
  do_output_section_address(unsigned int)
  { gold_unreachable(); }

  // Get the offset of a section--implemented by child class.
  virtual uint64_t
  do_output_section_offset(unsigned int) const
  { gold_unreachable(); }

  // Return the Xindex structure to use.
  virtual Xindex*
  do_initialize_xindex() = 0;

  // Implement get_global_symbol_counts--implemented by child class.
  virtual void
  do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const = 0;

  virtual const Symbols*
  do_get_global_symbols() const = 0;

  // Set the number of sections.
  void
  set_shnum(int shnum)
  { this->shnum_ = shnum; }

  // Functions used by both Sized_relobj_file and Sized_dynobj.

  // Read the section data into a Read_symbols_data object.
  template<int size, bool big_endian>
  void
  read_section_data(elfcpp::Elf_file<size, big_endian, Object>*,
		    Read_symbols_data*);

  // Find the section header with the given NAME.  If HDR is non-NULL
  // then it is a section header returned from a previous call to this
  // function and the next section header with the same name will be
  // returned.
  template<int size, bool big_endian>
  const unsigned char*
  find_shdr(const unsigned char* pshdrs, const char* name,
	    const char* names, section_size_type names_size,
	    const unsigned char* hdr) const;

  // Let the child class initialize the xindex object directly.
  void
  set_xindex(Xindex* xindex)
  {
    gold_assert(this->xindex_ == NULL);
    this->xindex_ = xindex;
  }

  // If NAME is the name of a special .gnu.warning section, arrange
  // for the warning to be issued.  SHNDX is the section index.
  // Return whether it is a warning section.
  bool
  handle_gnu_warning_section(const char* name, unsigned int shndx,
			     Symbol_table*);

  // If NAME is the name of the special section which indicates that
  // this object was compiled with -fsplit-stack, mark it accordingly,
  // and return true.  Otherwise return false.
  bool
  handle_split_stack_section(const char* name);

  // Discard any buffers of decompressed sections.  This is done
  // at the end of the Add_symbols task.
  virtual void
  do_discard_decompressed_sections()
  { }

  // Return the index of the first incremental relocation for symbol SYMNDX--
  // implemented by child class.
  virtual unsigned int
  do_get_incremental_reloc_base(unsigned int) const
  { gold_unreachable(); }

  // Return the number of incremental relocations for symbol SYMNDX--
  // implemented by child class.
  virtual unsigned int
  do_get_incremental_reloc_count(unsigned int) const
  { gold_unreachable(); }

  // Return the output view for a section.
  virtual unsigned char*
  do_get_output_view(unsigned int, section_size_type*) const
  { gold_unreachable(); }

  void
  set_compressed_sections(Compressed_section_map* compressed_sections)
  { this->compressed_sections_ = compressed_sections; }

  Compressed_section_map*
  compressed_sections()
  { return this->compressed_sections_; }

 private:
  // This class may not be copied.
  Object(const Object&);
  Object& operator=(const Object&);

  // Name of object as printed to user.
  std::string name_;
  // For reading the file.
  Input_file* input_file_;
  // Offset within the file--0 for an object file, non-0 for an
  // archive.
  off_t offset_;
  // Number of input sections.
  unsigned int shnum_;
  // Whether this is a dynamic object.
  bool is_dynamic_ : 1;
  // Whether this object is needed.  This is only set for dynamic
  // objects, and means that the object defined a symbol which was
  // used by a reference from a regular object.
  bool is_needed_ : 1;
  // Whether this object was compiled with -fsplit-stack.
  bool uses_split_stack_ : 1;
  // Whether this object contains any functions compiled with the
  // no_split_stack attribute.
  bool has_no_split_stack_ : 1;
  // True if exclude this object from automatic symbol export.
  // This is used only for archive objects.
  bool no_export_ : 1;
  // True if the object was found in a system directory.
  bool is_in_system_directory_ : 1;
  // True if the object was linked with --as-needed.
  bool as_needed_ : 1;
  // Many sections for objects with more than SHN_LORESERVE sections.
  Xindex* xindex_;
  // For compressed debug sections, map section index to uncompressed size
  // and contents.
  Compressed_section_map* compressed_sections_;
};

// A regular object (ET_REL).  This is an abstract base class itself.
// The implementation is the template class Sized_relobj_file.

class Relobj : public Object
{
 public:
  Relobj(const std::string& name, Input_file* input_file, off_t offset = 0)
    : Object(name, input_file, false, offset),
      output_sections_(),
      map_to_relocatable_relocs_(NULL),
      object_merge_map_(NULL),
      relocs_must_follow_section_writes_(false),
      sd_(NULL),
      reloc_counts_(NULL),
      reloc_bases_(NULL),
      first_dyn_reloc_(0),
      dyn_reloc_count_(0)
  { }

  // During garbage collection, the Read_symbols_data pass for 
  // each object is stored as layout needs to be done after 
  // reloc processing.
  Symbols_data* 
  get_symbols_data()
  { return this->sd_; }

  // Decides which section names have to be included in the worklist
  // as roots.
  bool
  is_section_name_included(const char* name);
 
  void
  copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
                    unsigned int section_header_size);

  void
  set_symbols_data(Symbols_data* sd)
  { this->sd_ = sd; }

  // During garbage collection, the Read_relocs pass for all objects 
  // is done before scanning the relocs.  In that case, this->rd_ is
  // used to store the information from Read_relocs for each object.
  // This data is also used to compute the list of relevant sections.
  Read_relocs_data*
  get_relocs_data()
  { return this->rd_; }

  void
  set_relocs_data(Read_relocs_data* rd)
  { this->rd_ = rd; }

  virtual bool
  is_output_section_offset_invalid(unsigned int shndx) const = 0;

  // Read the relocs.
  void
  read_relocs(Read_relocs_data* rd)
  { return this->do_read_relocs(rd); }

  // Process the relocs, during garbage collection only.
  void
  gc_process_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
  { return this->do_gc_process_relocs(symtab, layout, rd); }

  // Scan the relocs and adjust the symbol table.
  void
  scan_relocs(Symbol_table* symtab, Layout* layout, Read_relocs_data* rd)
  { return this->do_scan_relocs(symtab, layout, rd); }

  // Return the value of the local symbol whose index is SYMNDX, plus
  // ADDEND.  ADDEND is passed in so that we can correctly handle the
  // section symbol for a merge section.
  uint64_t
  local_symbol_value(unsigned int symndx, uint64_t addend) const
  { return this->do_local_symbol_value(symndx, addend); }

  // Return the PLT offset for a local symbol.  It is an error to call
  // this if it doesn't have one.
  unsigned int
  local_plt_offset(unsigned int symndx) const
  { return this->do_local_plt_offset(symndx); }

  // Return whether there is a GOT entry of type GOT_TYPE for the
  // local symbol SYMNDX with given ADDEND.
  bool
  local_has_got_offset(unsigned int symndx, unsigned int got_type,
		       uint64_t addend = 0) const
  { return this->do_local_has_got_offset(symndx, got_type, addend); }

  // Return the GOT offset of the GOT entry with type GOT_TYPE for the
  // local symbol SYMNDX with given ADDEND.  It is an error to call
  // this function if the symbol does not have such a GOT entry.
  unsigned int
  local_got_offset(unsigned int symndx, unsigned int got_type,
		   uint64_t addend = 0) const
  { return this->do_local_got_offset(symndx, got_type, addend); }

  // Set the GOT offset for a GOT entry with type GOT_TYPE for the
  // local symbol SYMNDX with ADDEND to GOT_OFFSET.  Create such an
  // entry if none exists.
  void
  set_local_got_offset(unsigned int symndx, unsigned int got_type,
		       unsigned int got_offset, uint64_t addend = 0)
  { this->do_set_local_got_offset(symndx, got_type, got_offset, addend); }

  // Return whether the local symbol SYMNDX is a TLS symbol.
  bool
  local_is_tls(unsigned int symndx) const
  { return this->do_local_is_tls(symndx); }

  // The number of local symbols in the input symbol table.
  virtual unsigned int
  local_symbol_count() const
  { return this->do_local_symbol_count(); }

  // The number of local symbols in the output symbol table.
  virtual unsigned int
  output_local_symbol_count() const
  { return this->do_output_local_symbol_count(); }

  // The file offset for local symbols in the output symbol table.
  virtual off_t
  local_symbol_offset() const
  { return this->do_local_symbol_offset(); }

  // Initial local symbol processing: count the number of local symbols
  // in the output symbol table and dynamic symbol table; add local symbol
  // names to *POOL and *DYNPOOL.
  void
  count_local_symbols(Stringpool_template<char>* pool,
                      Stringpool_template<char>* dynpool)
  { return this->do_count_local_symbols(pool, dynpool); }

  // Set the values of the local symbols, set the output symbol table
  // indexes for the local variables, and set the offset where local
  // symbol information will be stored. Returns the new local symbol index.
  unsigned int
  finalize_local_symbols(unsigned int index, off_t off, Symbol_table* symtab)
  { return this->do_finalize_local_symbols(index, off, symtab); }

  // Set the output dynamic symbol table indexes for the local variables.
  unsigned int
  set_local_dynsym_indexes(unsigned int index)
  { return this->do_set_local_dynsym_indexes(index); }

  // Set the offset where local dynamic symbol information will be stored.
  unsigned int
  set_local_dynsym_offset(off_t off)
  { return this->do_set_local_dynsym_offset(off); }

  // Record a dynamic relocation against an input section from this object.
  void
  add_dyn_reloc(unsigned int index)
  {
    if (this->dyn_reloc_count_ == 0)
      this->first_dyn_reloc_ = index;
    ++this->dyn_reloc_count_;
  }

  // Return the index of the first dynamic relocation.
  unsigned int
  first_dyn_reloc() const
  { return this->first_dyn_reloc_; }

  // Return the count of dynamic relocations.
  unsigned int
  dyn_reloc_count() const
  { return this->dyn_reloc_count_; }

  // Relocate the input sections and write out the local symbols.
  void
  relocate(const Symbol_table* symtab, const Layout* layout, Output_file* of)
  { return this->do_relocate(symtab, layout, of); }

  // Return whether an input section is being included in the link.
  bool
  is_section_included(unsigned int shndx) const
  {
    gold_assert(shndx < this->output_sections_.size());
    return this->output_sections_[shndx] != NULL;
  }

  // The output section of the input section with index SHNDX.
  // This is only used currently to remove a section from the link in
  // relaxation.
  void
  set_output_section(unsigned int shndx, Output_section* os)
  {
    gold_assert(shndx < this->output_sections_.size());
    this->output_sections_[shndx] = os;
  }
  
  // Set the offset of an input section within its output section.
  void
  set_section_offset(unsigned int shndx, uint64_t off)
  { this->do_set_section_offset(shndx, off); }

  // Return true if we need to wait for output sections to be written
  // before we can apply relocations.  This is true if the object has
  // any relocations for sections which require special handling, such
  // as the exception frame section.
  bool
  relocs_must_follow_section_writes() const
  { return this->relocs_must_follow_section_writes_; }

  Object_merge_map*
  get_or_create_merge_map();

  template<int size>
  void
  initialize_input_to_output_map(unsigned int shndx,
      typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
      Unordered_map<section_offset_type,
	    typename elfcpp::Elf_types<size>::Elf_Addr>* output_address) const;

  void
  add_merge_mapping(Output_section_data *output_data,
                    unsigned int shndx, section_offset_type offset,
                    section_size_type length,
                    section_offset_type output_offset);

  bool
  merge_output_offset(unsigned int shndx, section_offset_type offset,
                      section_offset_type *poutput) const;

  const Output_section_data*
  find_merge_section(unsigned int shndx) const;

  // Record the relocatable reloc info for an input reloc section.
  void
  set_relocatable_relocs(unsigned int reloc_shndx, Relocatable_relocs* rr)
  {
    gold_assert(reloc_shndx < this->shnum());
    (*this->map_to_relocatable_relocs_)[reloc_shndx] = rr;
  }

  // Get the relocatable reloc info for an input reloc section.
  Relocatable_relocs*
  relocatable_relocs(unsigned int reloc_shndx)
  {
    gold_assert(reloc_shndx < this->shnum());
    return (*this->map_to_relocatable_relocs_)[reloc_shndx];
  }

  // Layout sections whose layout was deferred while waiting for
  // input files from a plugin.
  void
  layout_deferred_sections(Layout* layout)
  { this->do_layout_deferred_sections(layout); }

  // Return the index of the first incremental relocation for symbol SYMNDX.
  virtual unsigned int
  do_get_incremental_reloc_base(unsigned int symndx) const
  { return this->reloc_bases_[symndx]; }

  // Return the number of incremental relocations for symbol SYMNDX.
  virtual unsigned int
  do_get_incremental_reloc_count(unsigned int symndx) const
  { return this->reloc_counts_[symndx]; }

  // Return the word size of the object file.
  int
  elfsize() const
  { return this->do_elfsize(); }

  // Return TRUE if this is a big-endian object file.
  bool
  is_big_endian() const
  { return this->do_is_big_endian(); }

 protected:
  // The output section to be used for each input section, indexed by
  // the input section number.  The output section is NULL if the
  // input section is to be discarded.
  typedef std::vector<Output_section*> Output_sections;

  // Read the relocs--implemented by child class.
  virtual void
  do_read_relocs(Read_relocs_data*) = 0;

  // Process the relocs--implemented by child class.
  virtual void
  do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;

  // Scan the relocs--implemented by child class.
  virtual void
  do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*) = 0;

  // Return the value of a local symbol.
  virtual uint64_t
  do_local_symbol_value(unsigned int symndx, uint64_t addend) const = 0;

  // Return the PLT offset of a local symbol.
  virtual unsigned int
  do_local_plt_offset(unsigned int symndx) const = 0;

  // Return whether a local symbol plus addend has a GOT offset
  // of a given type.
  virtual bool
  do_local_has_got_offset(unsigned int symndx,
			  unsigned int got_type, uint64_t addend) const = 0;

  // Return the GOT offset of a given type of a local symbol plus addend.
  virtual unsigned int
  do_local_got_offset(unsigned int symndx, unsigned int got_type,
		      uint64_t addend) const = 0;

  // Set the GOT offset with a given type for a local symbol plus addend.
  virtual void
  do_set_local_got_offset(unsigned int symndx, unsigned int got_type,
			  unsigned int got_offset, uint64_t addend) = 0;

  // Return whether local symbol SYMNDX is a TLS symbol.
  virtual bool
  do_local_is_tls(unsigned int symndx) const = 0;

  // Return the number of local symbols--implemented by child class.
  virtual unsigned int
  do_local_symbol_count() const = 0;

  // Return the number of output local symbols--implemented by child class.
  virtual unsigned int
  do_output_local_symbol_count() const = 0;

  // Return the file offset for local symbols--implemented by child class.
  virtual off_t
  do_local_symbol_offset() const = 0;

  // Count local symbols--implemented by child class.
  virtual void
  do_count_local_symbols(Stringpool_template<char>*,
			 Stringpool_template<char>*) = 0;

  // Finalize the local symbols.  Set the output symbol table indexes
  // for the local variables, and set the offset where local symbol
  // information will be stored.
  virtual unsigned int
  do_finalize_local_symbols(unsigned int, off_t, Symbol_table*) = 0;

  // Set the output dynamic symbol table indexes for the local variables.
  virtual unsigned int
  do_set_local_dynsym_indexes(unsigned int) = 0;

  // Set the offset where local dynamic symbol information will be stored.
  virtual unsigned int
  do_set_local_dynsym_offset(off_t) = 0;

  // Relocate the input sections and write out the local
  // symbols--implemented by child class.
  virtual void
  do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of) = 0;

  // Set the offset of a section--implemented by child class.
  virtual void
  do_set_section_offset(unsigned int shndx, uint64_t off) = 0;

  // Layout sections whose layout was deferred while waiting for
  // input files from a plugin--implemented by child class.
  virtual void
  do_layout_deferred_sections(Layout*) = 0;

  // Given a section index, return the corresponding Output_section.
  // The return value will be NULL if the section is not included in
  // the link.
  Output_section*
  do_output_section(unsigned int shndx) const
  {
    gold_assert(shndx < this->output_sections_.size());
    return this->output_sections_[shndx];
  }

  // Return the vector mapping input sections to output sections.
  Output_sections&
  output_sections()
  { return this->output_sections_; }

  const Output_sections&
  output_sections() const
  { return this->output_sections_; }

  // Set the size of the relocatable relocs array.
  void
  size_relocatable_relocs()
  {
    this->map_to_relocatable_relocs_ =
      new std::vector<Relocatable_relocs*>(this->shnum());
  }

  // Record that we must wait for the output sections to be written
  // before applying relocations.
  void
  set_relocs_must_follow_section_writes()
  { this->relocs_must_follow_section_writes_ = true; }

  // Allocate the array for counting incremental relocations.
  void
  allocate_incremental_reloc_counts()
  {
    unsigned int nsyms = this->do_get_global_symbols()->size();
    this->reloc_counts_ = new unsigned int[nsyms];
    gold_assert(this->reloc_counts_ != NULL);
    memset(this->reloc_counts_, 0, nsyms * sizeof(unsigned int));
  }

  // Record a relocation in this object referencing global symbol SYMNDX.
  // Used for tracking incremental link information.
  void
  count_incremental_reloc(unsigned int symndx)
  {
    unsigned int nsyms = this->do_get_global_symbols()->size();
    gold_assert(symndx < nsyms);
    gold_assert(this->reloc_counts_ != NULL);
    ++this->reloc_counts_[symndx];
  }

  // Finalize the incremental relocation information.
  void
  finalize_incremental_relocs(Layout* layout, bool clear_counts);

  // Return the index of the next relocation to be written for global symbol
  // SYMNDX.  Only valid after finalize_incremental_relocs() has been called.
  unsigned int
  next_incremental_reloc_index(unsigned int symndx)
  {
    unsigned int nsyms = this->do_get_global_symbols()->size();

    gold_assert(this->reloc_counts_ != NULL);
    gold_assert(this->reloc_bases_ != NULL);
    gold_assert(symndx < nsyms);

    unsigned int counter = this->reloc_counts_[symndx]++;
    return this->reloc_bases_[symndx] + counter;
  }

  // Return the word size of the object file--
  // implemented by child class.
  virtual int
  do_elfsize() const = 0;

  // Return TRUE if this is a big-endian object file--
  // implemented by child class.
  virtual bool
  do_is_big_endian() const = 0;

 private:
  // Mapping from input sections to output section.
  Output_sections output_sections_;
  // Mapping from input section index to the information recorded for
  // the relocations.  This is only used for a relocatable link.
  std::vector<Relocatable_relocs*>* map_to_relocatable_relocs_;
  // Mappings for merge sections.  This is managed by the code in the
  // Merge_map class.
  Object_merge_map* object_merge_map_;
  // Whether we need to wait for output sections to be written before
  // we can apply relocations.
  bool relocs_must_follow_section_writes_;
  // Used to store the relocs data computed by the Read_relocs pass. 
  // Used during garbage collection of unused sections.
  Read_relocs_data* rd_;
  // Used to store the symbols data computed by the Read_symbols pass.
  // Again used during garbage collection when laying out referenced
  // sections.
  gold::Symbols_data* sd_;
  // Per-symbol counts of relocations, for incremental links.
  unsigned int* reloc_counts_;
  // Per-symbol base indexes of relocations, for incremental links.
  unsigned int* reloc_bases_;
  // Index of the first dynamic relocation for this object.
  unsigned int first_dyn_reloc_;
  // Count of dynamic relocations for this object.
  unsigned int dyn_reloc_count_;
};

// This class is used to handle relocations against a section symbol
// in an SHF_MERGE section.  For such a symbol, we need to know the
// addend of the relocation before we can determine the final value.
// The addend gives us the location in the input section, and we can
// determine how it is mapped to the output section.  For a
// non-section symbol, we apply the addend to the final value of the
// symbol; that is done in finalize_local_symbols, and does not use
// this class.

template<int size>
class Merged_symbol_value
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;

  // We use a hash table to map offsets in the input section to output
  // addresses.
  typedef Unordered_map<section_offset_type, Value> Output_addresses;

  Merged_symbol_value(Value input_value, Value output_start_address)
    : input_value_(input_value), output_start_address_(output_start_address),
      output_addresses_()
  { }

  // Initialize the hash table.
  void
  initialize_input_to_output_map(const Relobj*, unsigned int input_shndx);

  // Release the hash table to save space.
  void
  free_input_to_output_map()
  { this->output_addresses_.clear(); }

  // Get the output value corresponding to an addend.  The object and
  // input section index are passed in because the caller will have
  // them; otherwise we could store them here.
  Value
  value(const Relobj* object, unsigned int input_shndx, Value addend) const
  {
    // This is a relocation against a section symbol.  ADDEND is the
    // offset in the section.  The result should be the start of some
    // merge area.  If the object file wants something else, it should
    // use a regular symbol rather than a section symbol.
    // Unfortunately, PR 6658 shows a case in which the object file
    // refers to the section symbol, but uses a negative ADDEND to
    // compensate for a PC relative reloc.  We can't handle the
    // general case.  However, we can handle the special case of a
    // negative addend, by assuming that it refers to the start of the
    // section.  Of course, that means that we have to guess when
    // ADDEND is negative.  It is normal to see a 32-bit value here
    // even when the template parameter size is 64, as 64-bit object
    // file formats have 32-bit relocations.  We know this is a merge
    // section, so we know it has to fit into memory.  So we assume
    // that we won't see a value larger than a large 32-bit unsigned
    // value.  This will break objects with very very large merge
    // sections; they probably break in other ways anyhow.
    Value input_offset = this->input_value_;
    if (addend < 0xffffff00)
      {
	input_offset += addend;
	addend = 0;
      }
    typename Output_addresses::const_iterator p =
      this->output_addresses_.find(input_offset);
    if (p != this->output_addresses_.end())
      return p->second + addend;

    return (this->value_from_output_section(object, input_shndx, input_offset)
	    + addend);
  }

 private:
  // Get the output value for an input offset if we couldn't find it
  // in the hash table.
  Value
  value_from_output_section(const Relobj*, unsigned int input_shndx,
			    Value input_offset) const;

  // The value of the section symbol in the input file.  This is
  // normally zero, but could in principle be something else.
  Value input_value_;
  // The start address of this merged section in the output file.
  Value output_start_address_;
  // A hash table which maps offsets in the input section to output
  // addresses.  This only maps specific offsets, not all offsets.
  Output_addresses output_addresses_;
};

// This POD class is holds the value of a symbol.  This is used for
// local symbols, and for all symbols during relocation processing.
// For special sections, such as SHF_MERGE sections, this calls a
// function to get the final symbol value.

template<int size>
class Symbol_value
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Value;

  Symbol_value()
    : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0),
      is_ordinary_shndx_(false), is_section_symbol_(false),
      is_tls_symbol_(false), is_ifunc_symbol_(false), has_output_value_(true)
  { this->u_.value = 0; }

  ~Symbol_value()
  {
    if (!this->has_output_value_)
      delete this->u_.merged_symbol_value;
  }

  // Get the value of this symbol.  OBJECT is the object in which this
  // symbol is defined, and ADDEND is an addend to add to the value.
  template<bool big_endian>
  Value
  value(const Sized_relobj_file<size, big_endian>* object, Value addend) const
  {
    if (this->has_output_value_)
      return this->u_.value + addend;
    else
      {
	gold_assert(this->is_ordinary_shndx_);
	return this->u_.merged_symbol_value->value(object, this->input_shndx_,
						   addend);
      }
  }

  // Set the value of this symbol in the output symbol table.
  void
  set_output_value(Value value)
  { this->u_.value = value; }

  // For a section symbol in a merged section, we need more
  // information.
  void
  set_merged_symbol_value(Merged_symbol_value<size>* msv)
  {
    gold_assert(this->is_section_symbol_);
    this->has_output_value_ = false;
    this->u_.merged_symbol_value = msv;
  }

  // Initialize the input to output map for a section symbol in a
  // merged section.  We also initialize the value of a non-section
  // symbol in a merged section.
  void
  initialize_input_to_output_map(const Relobj* object)
  {
    if (!this->has_output_value_)
      {
	gold_assert(this->is_section_symbol_ && this->is_ordinary_shndx_);
	Merged_symbol_value<size>* msv = this->u_.merged_symbol_value;
	msv->initialize_input_to_output_map(object, this->input_shndx_);
      }
  }

  // Free the input to output map for a section symbol in a merged
  // section.
  void
  free_input_to_output_map()
  {
    if (!this->has_output_value_)
      this->u_.merged_symbol_value->free_input_to_output_map();
  }

  // Set the value of the symbol from the input file.  This is only
  // called by count_local_symbols, to communicate the value to
  // finalize_local_symbols.
  void
  set_input_value(Value value)
  { this->u_.value = value; }

  // Return the input value.  This is only called by
  // finalize_local_symbols and (in special cases) relocate_section.
  Value
  input_value() const
  { return this->u_.value; }

  // Return whether we have set the index in the output symbol table
  // yet.
  bool
  is_output_symtab_index_set() const
  {
    return (this->output_symtab_index_ != 0
	    && this->output_symtab_index_ != -2U);
  }

  // Return whether this symbol may be discarded from the normal
  // symbol table.
  bool
  may_be_discarded_from_output_symtab() const
  {
    gold_assert(!this->is_output_symtab_index_set());
    return this->output_symtab_index_ != -2U;
  }

  // Return whether this symbol has an entry in the output symbol
  // table.
  bool
  has_output_symtab_entry() const
  {
    gold_assert(this->is_output_symtab_index_set());
    return this->output_symtab_index_ != -1U;
  }

  // Return the index in the output symbol table.
  unsigned int
  output_symtab_index() const
  {
    gold_assert(this->is_output_symtab_index_set()
		&& this->output_symtab_index_ != -1U);
    return this->output_symtab_index_;
  }

  // Set the index in the output symbol table.
  void
  set_output_symtab_index(unsigned int i)
  {
    gold_assert(!this->is_output_symtab_index_set());
    gold_assert(i != 0 && i != -1U && i != -2U);
    this->output_symtab_index_ = i;
  }

  // Record that this symbol should not go into the output symbol
  // table.
  void
  set_no_output_symtab_entry()
  {
    gold_assert(this->output_symtab_index_ == 0);
    this->output_symtab_index_ = -1U;
  }

  // Record that this symbol must go into the output symbol table,
  // because it there is a relocation that uses it.
  void
  set_must_have_output_symtab_entry()
  {
    gold_assert(!this->is_output_symtab_index_set());
    this->output_symtab_index_ = -2U;
  }

  // Set the index in the output dynamic symbol table.
  void
  set_needs_output_dynsym_entry()
  {
    gold_assert(!this->is_section_symbol());
    this->output_dynsym_index_ = 0;
  }

  // Return whether this symbol should go into the dynamic symbol
  // table.
  bool
  needs_output_dynsym_entry() const
  {
    return this->output_dynsym_index_ != -1U;
  }

  // Return whether this symbol has an entry in the dynamic symbol
  // table.
  bool
  has_output_dynsym_entry() const
  {
    gold_assert(this->output_dynsym_index_ != 0);
    return this->output_dynsym_index_ != -1U;
  }

  // Record that this symbol should go into the dynamic symbol table.
  void
  set_output_dynsym_index(unsigned int i)
  {
    gold_assert(this->output_dynsym_index_ == 0);
    gold_assert(i != 0 && i != -1U);
    this->output_dynsym_index_ = i;
  }

  // Return the index in the output dynamic symbol table.
  unsigned int
  output_dynsym_index() const
  {
    gold_assert(this->output_dynsym_index_ != 0
                && this->output_dynsym_index_ != -1U);
    return this->output_dynsym_index_;
  }

  // Set the index of the input section in the input file.
  void
  set_input_shndx(unsigned int i, bool is_ordinary)
  {
    this->input_shndx_ = i;
    // input_shndx_ field is a bitfield, so make sure that the value
    // fits.
    gold_assert(this->input_shndx_ == i);
    this->is_ordinary_shndx_ = is_ordinary;
  }

  // Return the index of the input section in the input file.
  unsigned int
  input_shndx(bool* is_ordinary) const
  {
    *is_ordinary = this->is_ordinary_shndx_;
    return this->input_shndx_;
  }

  // Whether this is a section symbol.
  bool
  is_section_symbol() const
  { return this->is_section_symbol_; }

  // Record that this is a section symbol.
  void
  set_is_section_symbol()
  {
    gold_assert(!this->needs_output_dynsym_entry());
    this->is_section_symbol_ = true;
  }

  // Record that this is a TLS symbol.
  void
  set_is_tls_symbol()
  { this->is_tls_symbol_ = true; }

  // Return true if this is a TLS symbol.
  bool
  is_tls_symbol() const
  { return this->is_tls_symbol_; }

  // Record that this is an IFUNC symbol.
  void
  set_is_ifunc_symbol()
  { this->is_ifunc_symbol_ = true; }

  // Return true if this is an IFUNC symbol.
  bool
  is_ifunc_symbol() const
  { return this->is_ifunc_symbol_; }

  // Return true if this has output value.
  bool
  has_output_value() const
  { return this->has_output_value_; }

 private:
  // The index of this local symbol in the output symbol table.  This
  // will be 0 if no value has been assigned yet, and the symbol may
  // be omitted.  This will be -1U if the symbol should not go into
  // the symbol table.  This will be -2U if the symbol must go into
  // the symbol table, but no index has been assigned yet.
  unsigned int output_symtab_index_;
  // The index of this local symbol in the dynamic symbol table.  This
  // will be -1U if the symbol should not go into the symbol table.
  unsigned int output_dynsym_index_;
  // The section index in the input file in which this symbol is
  // defined.
  unsigned int input_shndx_ : 27;
  // Whether the section index is an ordinary index, not a special
  // value.
  bool is_ordinary_shndx_ : 1;
  // Whether this is a STT_SECTION symbol.
  bool is_section_symbol_ : 1;
  // Whether this is a STT_TLS symbol.
  bool is_tls_symbol_ : 1;
  // Whether this is a STT_GNU_IFUNC symbol.
  bool is_ifunc_symbol_ : 1;
  // Whether this symbol has a value for the output file.  This is
  // normally set to true during Layout::finalize, by
  // finalize_local_symbols.  It will be false for a section symbol in
  // a merge section, as for such symbols we can not determine the
  // value to use in a relocation until we see the addend.
  bool has_output_value_ : 1;
  union
  {
    // This is used if has_output_value_ is true.  Between
    // count_local_symbols and finalize_local_symbols, this is the
    // value in the input file.  After finalize_local_symbols, it is
    // the value in the output file.
    Value value;
    // This is used if has_output_value_ is false.  It points to the
    // information we need to get the value for a merge section.
    Merged_symbol_value<size>* merged_symbol_value;
  } u_;
};

// This type is used to modify relocations for -fsplit-stack.  It is
// indexed by relocation index, and means that the relocation at that
// index should use the symbol from the vector, rather than the one
// indicated by the relocation.

class Reloc_symbol_changes
{
 public:
  Reloc_symbol_changes(size_t count)
    : vec_(count, NULL)
  { }

  void
  set(size_t i, Symbol* sym)
  { this->vec_[i] = sym; }

  const Symbol*
  operator[](size_t i) const
  { return this->vec_[i]; }

 private:
  std::vector<Symbol*> vec_;
};

// Abstract base class for a regular object file, either a real object file
// or an incremental (unchanged) object.  This is size and endian specific.

template<int size, bool big_endian>
class Sized_relobj : public Relobj
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
  typedef Relobj::Symbols Symbols;

  static const Address invalid_address = static_cast<Address>(0) - 1;

  Sized_relobj(const std::string& name, Input_file* input_file)
    : Relobj(name, input_file), local_got_offsets_(), section_offsets_()
  { }

  Sized_relobj(const std::string& name, Input_file* input_file,
		    off_t offset)
    : Relobj(name, input_file, offset), local_got_offsets_(), section_offsets_()
  { }

  ~Sized_relobj()
  { }

  // If this is a regular object, return a pointer to the Sized_relobj_file
  // object.  Otherwise, return NULL.
  virtual Sized_relobj_file<size, big_endian>*
  sized_relobj()
  { return NULL; }

  const virtual Sized_relobj_file<size, big_endian>*
  sized_relobj() const
  { return NULL; }

  // Checks if the offset of input section SHNDX within its output
  // section is invalid.
  bool
  is_output_section_offset_invalid(unsigned int shndx) const
  { return this->get_output_section_offset(shndx) == invalid_address; }

  // Get the offset of input section SHNDX within its output section.
  // This is -1 if the input section requires a special mapping, such
  // as a merge section.  The output section can be found in the
  // output_sections_ field of the parent class Relobj.
  Address
  get_output_section_offset(unsigned int shndx) const
  {
    gold_assert(shndx < this->section_offsets_.size());
    return this->section_offsets_[shndx];
  }

  // Iterate over local symbols, calling a visitor class V for each GOT offset
  // associated with a local symbol.
  void
  do_for_all_local_got_entries(Got_offset_list::Visitor* v) const;

 protected:
  typedef Relobj::Output_sections Output_sections;

  // Clear the local symbol information.
  void
  clear_got_offsets()
  { this->local_got_offsets_.clear(); }

  // Return the vector of section offsets.
  std::vector<Address>&
  section_offsets()
  { return this->section_offsets_; }

  // Get the address of an output section.
  uint64_t
  do_output_section_address(unsigned int shndx);

  // Get the offset of a section.
  uint64_t
  do_output_section_offset(unsigned int shndx) const
  {
    Address off = this->get_output_section_offset(shndx);
    if (off == invalid_address)
      return -1ULL;
    return off;
  }

  // Set the offset of a section.
  void
  do_set_section_offset(unsigned int shndx, uint64_t off)
  {
    gold_assert(shndx < this->section_offsets_.size());
    this->section_offsets_[shndx] =
      (off == static_cast<uint64_t>(-1)
       ? invalid_address
       : convert_types<Address, uint64_t>(off));
  }

  // Return whether the local symbol SYMNDX plus ADDEND has a GOT offset
  // of type GOT_TYPE.
  bool
  do_local_has_got_offset(unsigned int symndx, unsigned int got_type,
			  uint64_t addend) const
  {
    Local_got_entry_key key(symndx);
    Local_got_offsets::const_iterator p =
        this->local_got_offsets_.find(key);
    return (p != this->local_got_offsets_.end()
            && p->second->get_offset(got_type, addend) != -1U);
  }

  // Return the GOT offset of type GOT_TYPE of the local symbol
  // SYMNDX plus ADDEND.
  unsigned int
  do_local_got_offset(unsigned int symndx, unsigned int got_type,
			  uint64_t addend) const
  {
    Local_got_entry_key key(symndx);
    Local_got_offsets::const_iterator p =
        this->local_got_offsets_.find(key);
    gold_assert(p != this->local_got_offsets_.end());
    unsigned int off = p->second->get_offset(got_type, addend);
    gold_assert(off != -1U);
    return off;
  }

  // Set the GOT offset with type GOT_TYPE of the local symbol SYMNDX
  // plus ADDEND to GOT_OFFSET.
  void
  do_set_local_got_offset(unsigned int symndx, unsigned int got_type,
			  unsigned int got_offset, uint64_t addend)
  {
    Local_got_entry_key key(symndx);
    Local_got_offsets::const_iterator p =
        this->local_got_offsets_.find(key);
    if (p != this->local_got_offsets_.end())
      p->second->set_offset(got_type, got_offset, addend);
    else
      {
	Got_offset_list* g = new Got_offset_list(got_type, got_offset, addend);
        std::pair<Local_got_offsets::iterator, bool> ins =
            this->local_got_offsets_.insert(std::make_pair(key, g));
        gold_assert(ins.second);
      }
  }

  // Return the word size of the object file.
  virtual int
  do_elfsize() const
  { return size; }

  // Return TRUE if this is a big-endian object file.
  virtual bool
  do_is_big_endian() const
  { return big_endian; }

 private:
  // The GOT offsets of local symbols. This map also stores GOT offsets
  // for tp-relative offsets for TLS symbols.
  typedef Unordered_map<Local_got_entry_key, Got_offset_list*,
                        Local_got_entry_key::hash,
                        Local_got_entry_key::equal_to> Local_got_offsets;

  // GOT offsets for local non-TLS symbols, and tp-relative offsets
  // for TLS symbols, indexed by local got entry key class.
  Local_got_offsets local_got_offsets_;
  // For each input section, the offset of the input section in its
  // output section.  This is INVALID_ADDRESS if the input section requires a
  // special mapping.
  std::vector<Address> section_offsets_;
};

// A regular object file.  This is size and endian specific.

template<int size, bool big_endian>
class Sized_relobj_file : public Sized_relobj<size, big_endian>
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
  typedef typename Sized_relobj<size, big_endian>::Symbols Symbols;
  typedef std::vector<Symbol_value<size> > Local_values;

  static const Address invalid_address = static_cast<Address>(0) - 1;

  enum Compute_final_local_value_status
  {
    // No error.
    CFLV_OK,
    // An error occurred.
    CFLV_ERROR,
    // The local symbol has no output section.
    CFLV_DISCARDED
  };

  Sized_relobj_file(const std::string& name,
		    Input_file* input_file,
		    off_t offset,
		    const typename elfcpp::Ehdr<size, big_endian>&);

  ~Sized_relobj_file();

  // Set up the object file based on TARGET.
  void
  setup()
  { this->do_setup(); }

  // Return a pointer to the Sized_relobj_file object.
  Sized_relobj_file<size, big_endian>*
  sized_relobj()
  { return this; }

  const Sized_relobj_file<size, big_endian>*
  sized_relobj() const
  { return this; }

  // Return the ELF file type.
  int
  e_type() const
  { return this->e_type_; }

  // Return the EI_OSABI.
  const Osabi&
  osabi() const
  { return this->osabi_; }

  // Return the number of symbols.  This is only valid after
  // Object::add_symbols has been called.
  unsigned int
  symbol_count() const
  { return this->local_symbol_count_ + this->symbols_.size(); }

  // If SYM is the index of a global symbol in the object file's
  // symbol table, return the Symbol object.  Otherwise, return NULL.
  Symbol*
  global_symbol(unsigned int sym) const
  {
    if (sym >= this->local_symbol_count_)
      {
	gold_assert(sym - this->local_symbol_count_ < this->symbols_.size());
	return this->symbols_[sym - this->local_symbol_count_];
      }
    return NULL;
  }

  // Return the section index of symbol SYM.  Set *VALUE to its value
  // in the object file.  Set *IS_ORDINARY if this is an ordinary
  // section index, not a special code between SHN_LORESERVE and
  // SHN_HIRESERVE.  Note that for a symbol which is not defined in
  // this object file, this will set *VALUE to 0 and return SHN_UNDEF;
  // it will not return the final value of the symbol in the link.
  unsigned int
  symbol_section_and_value(unsigned int sym, Address* value, bool* is_ordinary);

  // Return a pointer to the Symbol_value structure which holds the
  // value of a local symbol.
  const Symbol_value<size>*
  local_symbol(unsigned int sym) const
  {
    gold_assert(sym < this->local_values_.size());
    return &this->local_values_[sym];
  }

  // Return the index of local symbol SYM in the ordinary symbol
  // table.  A value of -1U means that the symbol is not being output.
  unsigned int
  symtab_index(unsigned int sym) const
  {
    gold_assert(sym < this->local_values_.size());
    return this->local_values_[sym].output_symtab_index();
  }

  // Return the index of local symbol SYM in the dynamic symbol
  // table.  A value of -1U means that the symbol is not being output.
  unsigned int
  dynsym_index(unsigned int sym) const
  {
    gold_assert(sym < this->local_values_.size());
    return this->local_values_[sym].output_dynsym_index();
  }

  // Return the input section index of local symbol SYM.
  unsigned int
  local_symbol_input_shndx(unsigned int sym, bool* is_ordinary) const
  {
    gold_assert(sym < this->local_values_.size());
    return this->local_values_[sym].input_shndx(is_ordinary);
  }

  // Record that local symbol SYM must be in the output symbol table.
  void
  set_must_have_output_symtab_entry(unsigned int sym)
  {
    gold_assert(sym < this->local_values_.size());
    this->local_values_[sym].set_must_have_output_symtab_entry();
  }

  // Record that local symbol SYM needs a dynamic symbol entry.
  void
  set_needs_output_dynsym_entry(unsigned int sym)
  {
    gold_assert(sym < this->local_values_.size());
    this->local_values_[sym].set_needs_output_dynsym_entry();
  }

  // Return whether the local symbol SYMNDX has a PLT offset.
  bool
  local_has_plt_offset(unsigned int symndx) const;

  // Set the PLT offset of the local symbol SYMNDX.
  void
  set_local_plt_offset(unsigned int symndx, unsigned int plt_offset);

  // Adjust this local symbol value.  Return false if the symbol
  // should be discarded from the output file.
  bool
  adjust_local_symbol(Symbol_value<size>* lv) const
  { return this->do_adjust_local_symbol(lv); }

  // Return the name of the symbol that spans the given offset in the
  // specified section in this object.  This is used only for error
  // messages and is not particularly efficient.
  bool
  get_symbol_location_info(unsigned int shndx, off_t offset,
			   Symbol_location_info* info);

  // Look for a kept section corresponding to the given discarded section,
  // and return its output address.  This is used only for relocations in
  // debugging sections.
  Address
  map_to_kept_section(unsigned int shndx, std::string& section_name,
		      bool* found) const;

  // Look for a kept section corresponding to the given discarded section,
  // and return its object file.
  Relobj*
  find_kept_section_object(unsigned int shndx, unsigned int* symndx_p) const;

  // Return the name of symbol SYMNDX.
  const char*
  get_symbol_name(unsigned int symndx);

  // Compute final local symbol value.  R_SYM is the local symbol index.
  // LV_IN points to a local symbol value containing the input value.
  // LV_OUT points to a local symbol value storing the final output value,
  // which must not be a merged symbol value since before calling this
  // method to avoid memory leak.  SYMTAB points to a symbol table.
  //
  // The method returns a status code at return.  If the return status is
  // CFLV_OK, *LV_OUT contains the final value.  If the return status is
  // CFLV_ERROR, *LV_OUT is 0.  If the return status is CFLV_DISCARDED,
  // *LV_OUT is not modified.
  Compute_final_local_value_status
  compute_final_local_value(unsigned int r_sym,
			    const Symbol_value<size>* lv_in,
			    Symbol_value<size>* lv_out,
			    const Symbol_table* symtab);

  // Return true if the layout for this object was deferred.
  bool is_deferred_layout() const
  { return this->is_deferred_layout_; }

 protected:
  typedef typename Sized_relobj<size, big_endian>::Output_sections
      Output_sections;

  // Set up.
  virtual void
  do_setup();

  // Read the symbols.
  void
  do_read_symbols(Read_symbols_data*);

  // Read the symbols.  This is common code for all target-specific
  // overrides of do_read_symbols.
  void
  base_read_symbols(Read_symbols_data*);

  // Return the value of a local symbol.
  uint64_t
  do_local_symbol_value(unsigned int symndx, uint64_t addend) const
  {
    const Symbol_value<size>* symval = this->local_symbol(symndx);
    return symval->value(this, addend);
  }

  // Return the PLT offset for a local symbol.  It is an error to call
  // this if it doesn't have one.
  unsigned int
  do_local_plt_offset(unsigned int symndx) const;

  // Return whether local symbol SYMNDX is a TLS symbol.
  bool
  do_local_is_tls(unsigned int symndx) const
  { return this->local_symbol(symndx)->is_tls_symbol(); }

  // Return the number of local symbols.
  unsigned int
  do_local_symbol_count() const
  { return this->local_symbol_count_; }

  // Return the number of local symbols in the output symbol table.
  unsigned int
  do_output_local_symbol_count() const
  { return this->output_local_symbol_count_; }

  // Return the number of local symbols in the output symbol table.
  off_t
  do_local_symbol_offset() const
  { return this->local_symbol_offset_; }

  // Lay out the input sections.
  void
  do_layout(Symbol_table*, Layout*, Read_symbols_data*);

  // Layout sections whose layout was deferred while waiting for
  // input files from a plugin.
  void
  do_layout_deferred_sections(Layout*);

  // Add the symbols to the symbol table.
  void
  do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);

  Archive::Should_include
  do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
                           std::string* why);

  // Iterate over global symbols, calling a visitor class V for each.
  void
  do_for_all_global_symbols(Read_symbols_data* sd,
			    Library_base::Symbol_visitor_base* v);

  // Read the relocs.
  void
  do_read_relocs(Read_relocs_data*);

  // Process the relocs to find list of referenced sections. Used only
  // during garbage collection.
  void
  do_gc_process_relocs(Symbol_table*, Layout*, Read_relocs_data*);

  // Scan the relocs and adjust the symbol table.
  void
  do_scan_relocs(Symbol_table*, Layout*, Read_relocs_data*);

  // Count the local symbols.
  void
  do_count_local_symbols(Stringpool_template<char>*,
                            Stringpool_template<char>*);

  // Finalize the local symbols.
  unsigned int
  do_finalize_local_symbols(unsigned int, off_t, Symbol_table*);

  // Set the offset where local dynamic symbol information will be stored.
  unsigned int
  do_set_local_dynsym_indexes(unsigned int);

  // Set the offset where local dynamic symbol information will be stored.
  unsigned int
  do_set_local_dynsym_offset(off_t);

  // Relocate the input sections and write out the local symbols.
  void
  do_relocate(const Symbol_table* symtab, const Layout*, Output_file* of);

  // Get the size of a section.
  uint64_t
  do_section_size(unsigned int shndx)
  { return this->elf_file_.section_size(shndx); }

  // Get the name of a section.
  std::string
  do_section_name(unsigned int shndx) const
  { return this->elf_file_.section_name(shndx); }

  // Return the location of the contents of a section.
  const unsigned char*
  do_section_contents(unsigned int shndx, section_size_type* plen,
		      bool cache)
  {
    Object::Location loc(this->elf_file_.section_contents(shndx));
    *plen = convert_to_section_size_type(loc.data_size);
    if (*plen == 0)
      {
	static const unsigned char empty[1] = { '\0' };
	return empty;
      }
    return this->get_view(loc.file_offset, *plen, true, cache);
  }

  // Return section flags.
  uint64_t
  do_section_flags(unsigned int shndx);

  // Return section entsize.
  uint64_t
  do_section_entsize(unsigned int shndx);

  // Return section address.
  uint64_t
  do_section_address(unsigned int shndx)
  { return this->elf_file_.section_addr(shndx); }

  // Return section type.
  unsigned int
  do_section_type(unsigned int shndx)
  { return this->elf_file_.section_type(shndx); }

  // Return the section link field.
  unsigned int
  do_section_link(unsigned int shndx)
  { return this->elf_file_.section_link(shndx); }

  // Return the section info field.
  unsigned int
  do_section_info(unsigned int shndx)
  { return this->elf_file_.section_info(shndx); }

  // Return the section alignment.
  uint64_t
  do_section_addralign(unsigned int shndx)
  { return this->elf_file_.section_addralign(shndx); }

  // Return the Xindex structure to use.
  Xindex*
  do_initialize_xindex();

  // Get symbol counts.
  void
  do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;

  // Get the global symbols.
  const Symbols*
  do_get_global_symbols() const
  { return &this->symbols_; }

  // Adjust a section index if necessary.
  unsigned int
  adjust_shndx(unsigned int shndx)
  {
    if (shndx >= elfcpp::SHN_LORESERVE)
      shndx += this->elf_file_.large_shndx_offset();
    return shndx;
  }

  // Initialize input to output maps for section symbols in merged
  // sections.
  void
  initialize_input_to_output_maps();

  // Free the input to output maps for section symbols in merged
  // sections.
  void
  free_input_to_output_maps();

  // Return symbol table section index.
  unsigned int
  symtab_shndx() const
  { return this->symtab_shndx_; }

  // Allow a child class to access the ELF file.
  elfcpp::Elf_file<size, big_endian, Object>*
  elf_file()
  { return &this->elf_file_; }
  
  // Allow a child class to access the local values.
  Local_values*
  local_values()
  { return &this->local_values_; }

  // Views and sizes when relocating.
  struct View_size
  {
    unsigned char* view;
    typename elfcpp::Elf_types<size>::Elf_Addr address;
    off_t offset;
    section_size_type view_size;
    bool is_input_output_view;
    bool is_postprocessing_view;
    bool is_ctors_reverse_view;
  };

  typedef std::vector<View_size> Views;

  // Stash away info for a number of special sections.
  // Return true if any of the sections found require local symbols to be read.
  virtual bool
  do_find_special_sections(Read_symbols_data* sd);

  // This may be overriden by a child class.
  virtual void
  do_relocate_sections(const Symbol_table* symtab, const Layout* layout,
		       const unsigned char* pshdrs, Output_file* of,
		       Views* pviews);

  // Relocate section data for a range of sections.
  void
  relocate_section_range(const Symbol_table* symtab, const Layout* layout,
			 const unsigned char* pshdrs, Output_file* of,
			 Views* pviews, unsigned int start_shndx,
			 unsigned int end_shndx);

  // Adjust this local symbol value.  Return false if the symbol
  // should be discarded from the output file.
  virtual bool
  do_adjust_local_symbol(Symbol_value<size>*) const
  { return true; }

  // Allow a child to set output local symbol count.
  void
  set_output_local_symbol_count(unsigned int value)
  { this->output_local_symbol_count_ = value; }

  // Return the output view for a section.
  unsigned char*
  do_get_output_view(unsigned int, section_size_type*) const;

 private:
  // For convenience.
  typedef Sized_relobj_file<size, big_endian> This;
  static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
  static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
  static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
  typedef elfcpp::Shdr<size, big_endian> Shdr;
  typedef elfcpp::Shdr_write<size, big_endian> Shdr_write;

  // To keep track of discarded comdat sections, we need to map a member
  // section index to the object and section index of the corresponding
  // kept section.
  struct Kept_comdat_section
  {
    Kept_comdat_section(uint64_t a_sh_size, Kept_section* a_kept_section,
			unsigned int a_symndx, bool a_is_comdat)
      : sh_size(a_sh_size), kept_section(a_kept_section),
	symndx (a_symndx), is_comdat(a_is_comdat)
    { }
    uint64_t sh_size;		// Section size
    Kept_section* kept_section;	// Kept section info
    unsigned int symndx;	// Index of key symbol
    bool is_comdat;		// True if comdat group, false if linkonce
  };
  typedef std::map<unsigned int, Kept_comdat_section>
      Kept_comdat_section_table;

  // Find the SHT_SYMTAB section, given the section headers.
  void
  find_symtab(const unsigned char* pshdrs);

  // Return whether SHDR has the right flags for a GNU style exception
  // frame section.
  bool
  check_eh_frame_flags(const elfcpp::Shdr<size, big_endian>* shdr) const;

  // Return whether there is a section named .eh_frame which might be
  // a GNU style exception frame section.
  bool
  find_eh_frame(const unsigned char* pshdrs, const char* names,
		section_size_type names_size) const;

  // Whether to include a section group in the link.
  bool
  include_section_group(Symbol_table*, Layout*, unsigned int, const char*,
			const unsigned char*, const char*, section_size_type,
			std::vector<bool>*);

  // Whether to include a linkonce section in the link.
  bool
  include_linkonce_section(Layout*, unsigned int, const char*,
			   const elfcpp::Shdr<size, big_endian>&);

  // Layout an input section.
  void
  layout_section(Layout* layout, unsigned int shndx, const char* name,
                 const typename This::Shdr& shdr, unsigned int sh_type,
                 unsigned int reloc_shndx, unsigned int reloc_type);

  // Layout an input .eh_frame section.
  void
  layout_eh_frame_section(Layout* layout, const unsigned char* symbols_data,
			  section_size_type symbols_size,
			  const unsigned char* symbol_names_data,
			  section_size_type symbol_names_size,
			  unsigned int shndx, const typename This::Shdr&,
			  unsigned int reloc_shndx, unsigned int reloc_type);

  // Layout an input .note.gnu.property section.
  void
  layout_gnu_property_section(Layout* layout, unsigned int shndx);

  // Write section data to the output file.  Record the views and
  // sizes in VIEWS for use when relocating.
  void
  write_sections(const Layout*, const unsigned char* pshdrs, Output_file*,
		 Views*);

  // Relocate the sections in the output file.
  void
  relocate_sections(const Symbol_table* symtab, const Layout* layout,
		    const unsigned char* pshdrs, Output_file* of,
		    Views* pviews)
  { this->do_relocate_sections(symtab, layout, pshdrs, of, pviews); }

  // Reverse the words in a section.  Used for .ctors sections mapped
  // to .init_array sections.
  void
  reverse_words(unsigned char*, section_size_type);

  // Scan the input relocations for --emit-relocs.
  void
  emit_relocs_scan(Symbol_table*, Layout*, const unsigned char* plocal_syms,
		   const Read_relocs_data::Relocs_list::iterator&);

  // Scan the input relocations for --emit-relocs, templatized on the
  // type of the relocation section.
  template<int sh_type>
  void
  emit_relocs_scan_reltype(Symbol_table*, Layout*,
			   const unsigned char* plocal_syms,
			   const Read_relocs_data::Relocs_list::iterator&,
			   Relocatable_relocs*);

  // Scan the input relocations for --incremental.
  void
  incremental_relocs_scan(const Read_relocs_data::Relocs_list::iterator&);

  // Scan the input relocations for --incremental, templatized on the
  // type of the relocation section.
  template<int sh_type>
  void
  incremental_relocs_scan_reltype(
      const Read_relocs_data::Relocs_list::iterator&);

  void
  incremental_relocs_write(const Relocate_info<size, big_endian>*,
			   unsigned int sh_type,
			   const unsigned char* prelocs,
			   size_t reloc_count,
			   Output_section*,
			   Address output_offset,
			   Output_file*);

  template<int sh_type>
  void
  incremental_relocs_write_reltype(const Relocate_info<size, big_endian>*,
				   const unsigned char* prelocs,
				   size_t reloc_count,
				   Output_section*,
				   Address output_offset,
				   Output_file*);

  // A type shared by split_stack_adjust_reltype and find_functions.
  typedef std::map<section_offset_type, section_size_type> Function_offsets;

  // Check for -fsplit-stack routines calling non-split-stack routines.
  void
  split_stack_adjust(const Symbol_table*, const unsigned char* pshdrs,
		     unsigned int sh_type, unsigned int shndx,
		     const unsigned char* prelocs, size_t reloc_count,
		     unsigned char* view, section_size_type view_size,
		     Reloc_symbol_changes** reloc_map,
		     const Sized_target<size, big_endian>* target);

  template<int sh_type>
  void
  split_stack_adjust_reltype(const Symbol_table*, const unsigned char* pshdrs,
			     unsigned int shndx, const unsigned char* prelocs,
			     size_t reloc_count, unsigned char* view,
			     section_size_type view_size,
			     Reloc_symbol_changes** reloc_map,
			     const Sized_target<size, big_endian>* target);

  // Find all functions in a section.
  void
  find_functions(const unsigned char* pshdrs, unsigned int shndx,
		 Function_offsets*);

  // Write out the local symbols.
  void
  write_local_symbols(Output_file*,
		      const Stringpool_template<char>*,
		      const Stringpool_template<char>*,
		      Output_symtab_xindex*,
		      Output_symtab_xindex*,
		      off_t);

  // Record a mapping from discarded section SHNDX to the corresponding
  // kept section.
  void
  set_kept_comdat_section(unsigned int shndx, bool is_comdat,
			  unsigned int symndx, uint64_t sh_size,
			  Kept_section* kept_section)
  {
    Kept_comdat_section kept(sh_size, kept_section, symndx, is_comdat);
    this->kept_comdat_sections_.insert(std::make_pair(shndx, kept));
  }

  // Find the kept section corresponding to the discarded section
  // SHNDX.  Return true if found.
  bool
  get_kept_comdat_section(unsigned int shndx, bool* is_comdat,
			  unsigned int *symndx, uint64_t* sh_size,
			  Kept_section** kept_section) const
  {
    typename Kept_comdat_section_table::const_iterator p =
      this->kept_comdat_sections_.find(shndx);
    if (p == this->kept_comdat_sections_.end())
      return false;
    *is_comdat = p->second.is_comdat;
    *symndx = p->second.symndx;
    *sh_size = p->second.sh_size;
    *kept_section = p->second.kept_section;
    return true;
  }

  // Compute final local symbol value.  R_SYM is the local symbol index.
  // LV_IN points to a local symbol value containing the input value.
  // LV_OUT points to a local symbol value storing the final output value,
  // which must not be a merged symbol value since before calling this
  // method to avoid memory leak.  RELOCATABLE indicates whether we are
  // linking a relocatable output.  OUT_SECTIONS is an array of output
  // sections.  OUT_OFFSETS is an array of offsets of the sections.  SYMTAB
  // points to a symbol table.
  //
  // The method returns a status code at return.  If the return status is
  // CFLV_OK, *LV_OUT contains the final value.  If the return status is
  // CFLV_ERROR, *LV_OUT is 0.  If the return status is CFLV_DISCARDED,
  // *LV_OUT is not modified.
  inline Compute_final_local_value_status
  compute_final_local_value_internal(unsigned int r_sym,
				     const Symbol_value<size>* lv_in,
				     Symbol_value<size>* lv_out,
				     bool relocatable,
				     const Output_sections& out_sections,
				     const std::vector<Address>& out_offsets,
				     const Symbol_table* symtab);

  // The PLT offsets of local symbols.
  typedef Unordered_map<unsigned int, unsigned int> Local_plt_offsets;

  // Saved information for sections whose layout was deferred.
  struct Deferred_layout
  {
    static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
    Deferred_layout(unsigned int shndx, const char* name,
                    unsigned int sh_type,
                    const unsigned char* pshdr,
                    unsigned int reloc_shndx, unsigned int reloc_type)
      : name_(name), shndx_(shndx), reloc_shndx_(reloc_shndx),
        reloc_type_(reloc_type)
    {
      typename This::Shdr_write shdr(this->shdr_data_);
      memcpy(this->shdr_data_, pshdr, shdr_size);
      shdr.put_sh_type(sh_type);
    }
    std::string name_;
    unsigned int shndx_;
    unsigned int reloc_shndx_;
    unsigned int reloc_type_;
    unsigned char shdr_data_[shdr_size];
  };

  // General access to the ELF file.
  elfcpp::Elf_file<size, big_endian, Object> elf_file_;
  // The EI_OSABI.
  const Osabi osabi_;
  // Type of ELF file (ET_REL or ET_EXEC).  ET_EXEC files are allowed
  // as input files only for the --just-symbols option.
  int e_type_;
  // Index of SHT_SYMTAB section.
  unsigned int symtab_shndx_;
  // The number of local symbols.
  unsigned int local_symbol_count_;
  // The number of local symbols which go into the output file.
  unsigned int output_local_symbol_count_;
  // The number of local symbols which go into the output file's dynamic
  // symbol table.
  unsigned int output_local_dynsym_count_;
  // The entries in the symbol table for the external symbols.
  Symbols symbols_;
  // Number of symbols defined in object file itself.
  size_t defined_count_;
  // File offset for local symbols (relative to start of symbol table).
  off_t local_symbol_offset_;
  // File offset for local dynamic symbols (absolute).
  off_t local_dynsym_offset_;
  // Values of local symbols.
  Local_values local_values_;
  // PLT offsets for local symbols.
  Local_plt_offsets local_plt_offsets_;
  // Table mapping discarded comdat sections to corresponding kept sections.
  Kept_comdat_section_table kept_comdat_sections_;
  // Whether this object has a GNU style .eh_frame section.
  bool has_eh_frame_;
  // True if the layout of this object was deferred, waiting for plugin
  // replacement files.
  bool is_deferred_layout_;
  // The list of sections whose layout was deferred.
  std::vector<Deferred_layout> deferred_layout_;
  // The list of relocation sections whose layout was deferred.
  std::vector<Deferred_layout> deferred_layout_relocs_;
  // Pointer to the list of output views; valid only during do_relocate().
  const Views* output_views_;
};

// A class to manage the list of all objects.

class Input_objects
{
 public:
  Input_objects()
    : relobj_list_(), dynobj_list_(), sonames_(), cref_(NULL)
  { }

  // The type of the list of input relocateable objects.
  typedef std::vector<Relobj*> Relobj_list;
  typedef Relobj_list::const_iterator Relobj_iterator;

  // The type of the list of input dynamic objects.
  typedef std::vector<Dynobj*> Dynobj_list;
  typedef Dynobj_list::const_iterator Dynobj_iterator;

  // Add an object to the list.  Return true if all is well, or false
  // if this object should be ignored.
  bool
  add_object(Object*);

  // Start processing an archive.
  void
  archive_start(Archive*);

  // Stop processing an archive.
  void
  archive_stop(Archive*);

  // For each dynamic object, check whether we've seen all of its
  // explicit dependencies.
  void
  check_dynamic_dependencies() const;

  // Return whether an object was found in the system library
  // directory.
  bool
  found_in_system_library_directory(const Object*) const;

  // Print symbol counts.
  void
  print_symbol_counts(const Symbol_table*) const;

  // Print a cross reference table.
  void
  print_cref(const Symbol_table*, FILE*) const;

  // Iterate over all regular objects.

  Relobj_iterator
  relobj_begin() const
  { return this->relobj_list_.begin(); }

  Relobj_iterator
  relobj_end() const
  { return this->relobj_list_.end(); }

  // Iterate over all dynamic objects.

  Dynobj_iterator
  dynobj_begin() const
  { return this->dynobj_list_.begin(); }

  Dynobj_iterator
  dynobj_end() const
  { return this->dynobj_list_.end(); }

  // Return whether we have seen any dynamic objects.
  bool
  any_dynamic() const
  { return !this->dynobj_list_.empty(); }

  // Return the number of non dynamic objects.
  int
  number_of_relobjs() const
  { return this->relobj_list_.size(); }

  // Return the number of input objects.
  int
  number_of_input_objects() const
  { return this->relobj_list_.size() + this->dynobj_list_.size(); }

 private:
  Input_objects(const Input_objects&);
  Input_objects& operator=(const Input_objects&);

  // The list of ordinary objects included in the link.
  Relobj_list relobj_list_;
  // The list of dynamic objects included in the link.
  Dynobj_list dynobj_list_;
  // SONAMEs that we have seen.
  Unordered_map<std::string, Object*> sonames_;
  // Manage cross-references if requested.
  Cref* cref_;
};

// Some of the information we pass to the relocation routines.  We
// group this together to avoid passing a dozen different arguments.

template<int size, bool big_endian>
struct Relocate_info
{
  // Symbol table.
  const Symbol_table* symtab;
  // Layout.
  const Layout* layout;
  // Object being relocated.
  Sized_relobj_file<size, big_endian>* object;
  // Section index of relocation section.
  unsigned int reloc_shndx;
  // Section header of relocation section.
  const unsigned char* reloc_shdr;
  // Info about how relocs should be handled
  Relocatable_relocs* rr;
  // Section index of section being relocated.
  unsigned int data_shndx;
  // Section header of data section.
  const unsigned char* data_shdr;

  // Return a string showing the location of a relocation.  This is
  // only used for error messages.
  std::string
  location(size_t relnum, off_t reloffset) const;
};

// This is used to represent a section in an object and is used as the
// key type for various section maps.
typedef std::pair<Relobj*, unsigned int> Section_id;

// This is similar to Section_id but is used when the section
// pointers are const.
typedef std::pair<const Relobj*, unsigned int> Const_section_id;

// The hash value is based on the address of an object in memory during
// linking.  It is okay to use this for looking up sections but never use
// this in an unordered container that we want to traverse in a repeatable
// manner.

struct Section_id_hash
{
  size_t operator()(const Section_id& loc) const
  { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
};

struct Const_section_id_hash
{
  size_t operator()(const Const_section_id& loc) const
  { return reinterpret_cast<uintptr_t>(loc.first) ^ loc.second; }
};

// Return whether INPUT_FILE contains an ELF object start at file
// offset OFFSET.  This sets *START to point to a view of the start of
// the file.  It sets *READ_SIZE to the number of bytes in the view.

extern bool
is_elf_object(Input_file* input_file, off_t offset,
	      const unsigned char** start, int* read_size);

// Return an Object appropriate for the input file.  P is BYTES long,
// and holds the ELF header.  If PUNCONFIGURED is not NULL, then if
// this sees an object the linker is not configured to support, it
// sets *PUNCONFIGURED to true and returns NULL without giving an
// error message.

extern Object*
make_elf_object(const std::string& name, Input_file*,
		off_t offset, const unsigned char* p,
		section_offset_type bytes, bool* punconfigured);

} // end namespace gold

#endif // !defined(GOLD_OBJECT_H)