File: incremental.h

package info (click to toggle)
binutils 2.28-5
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 271,848 kB
  • sloc: ansic: 1,419,727; asm: 623,424; cpp: 125,042; exp: 64,226; makefile: 56,536; sh: 21,234; lisp: 15,206; yacc: 14,889; perl: 2,111; ada: 1,681; lex: 1,645; pascal: 1,438; cs: 879; sed: 195; python: 154; xml: 95; awk: 25
file content (2255 lines) | stat: -rw-r--r-- 65,532 bytes parent folder | download
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
// inremental.h -- incremental linking support for gold   -*- C++ -*-

// Copyright (C) 2009-2017 Free Software Foundation, Inc.
// Written by Mikolaj Zalewski <mikolajz@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_INCREMENTAL_H
#define GOLD_INCREMENTAL_H

#include <map>
#include <vector>

#include "elfcpp_file.h"
#include "stringpool.h"
#include "workqueue.h"
#include "fileread.h"
#include "output.h"
#include "archive.h"

namespace gold
{

class Input_argument;
class Incremental_inputs_checker;
class Incremental_script_entry;
class Incremental_object_entry;
class Incremental_dynobj_entry;
class Incremental_archive_entry;
class Incremental_inputs;
class Incremental_binary;
class Incremental_library;
class Object;

// Incremental input type as stored in .gnu_incremental_inputs.

enum Incremental_input_type
{
  INCREMENTAL_INPUT_OBJECT = 1,
  INCREMENTAL_INPUT_ARCHIVE_MEMBER = 2,
  INCREMENTAL_INPUT_ARCHIVE = 3,
  INCREMENTAL_INPUT_SHARED_LIBRARY = 4,
  INCREMENTAL_INPUT_SCRIPT = 5
};

// Incremental input file flags.
// The input file type is stored in the lower eight bits.

enum Incremental_input_flags
{
  INCREMENTAL_INPUT_IN_SYSTEM_DIR = 0x8000,
  INCREMENTAL_INPUT_AS_NEEDED = 0x4000
};

// Symbol flags for the incremental symbol table.
// These flags are stored in the top two bits of
// the symbol index field.

enum Incremental_shlib_symbol_flags
{
  // Symbol is defined in this library.
  INCREMENTAL_SHLIB_SYM_DEF = 2,
  // Symbol is defined in this library, with a COPY relocation.
  INCREMENTAL_SHLIB_SYM_COPY = 3
};

static const int INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT = 30;

// Return TRUE if a section of type SH_TYPE can be updated in place
// during an incremental update.
bool
can_incremental_update(unsigned int sh_type);

// Create an Incremental_binary object for FILE. Returns NULL is this is not
// possible, e.g. FILE is not an ELF file or has an unsupported target.

Incremental_binary*
open_incremental_binary(Output_file* file);

// Base class for recording each input file.

class Incremental_input_entry
{
 public:
  Incremental_input_entry(Stringpool::Key filename_key, unsigned int arg_serial,
			  Timespec mtime)
    : filename_key_(filename_key), file_index_(0), offset_(0), info_offset_(0),
      arg_serial_(arg_serial), mtime_(mtime), is_in_system_directory_(false),
      as_needed_(false)
  { }

  virtual
  ~Incremental_input_entry()
  { }

  // Return the type of input file.
  Incremental_input_type
  type() const
  { return this->do_type(); }

  // Set the index and section offset of this input file entry.
  void
  set_offset(unsigned int file_index, unsigned int offset)
  {
    this->file_index_ = file_index;
    this->offset_ = offset;
  }

  // Set the section offset of the supplemental information for this entry.
  void
  set_info_offset(unsigned int info_offset)
  { this->info_offset_ = info_offset; }

  // Get the index of this input file entry.
  unsigned int
  get_file_index() const
  { return this->file_index_; }

  // Get the section offset of this input file entry.
  unsigned int
  get_offset() const
  { return this->offset_; }

  // Get the section offset of the supplemental information for this entry.
  unsigned int
  get_info_offset() const
  { return this->info_offset_; }

  // Get the stringpool key for the input filename.
  Stringpool::Key
  get_filename_key() const
  { return this->filename_key_; }

  // Get the serial number of the input file.
  unsigned int
  arg_serial() const
  { return this->arg_serial_; }

  // Get the modification time of the input file.
  const Timespec&
  get_mtime() const
  { return this->mtime_; }

  // Record that the file was found in a system directory.
  void
  set_is_in_system_directory()
  { this->is_in_system_directory_ = true; }

  // Return TRUE if the file was found in a system directory.
  bool
  is_in_system_directory() const
  { return this->is_in_system_directory_; }

  // Record that the file was linked with --as-needed.
  void
  set_as_needed()
  { this->as_needed_ = true; }

  // Return TRUE if the file was linked with --as-needed.
  bool
  as_needed() const
  { return this->as_needed_; }

  // Return a pointer to the derived Incremental_script_entry object.
  // Return NULL for input entries that are not script files.
  Incremental_script_entry*
  script_entry()
  { return this->do_script_entry(); }

  // Return a pointer to the derived Incremental_object_entry object.
  // Return NULL for input entries that are not object files.
  Incremental_object_entry*
  object_entry()
  { return this->do_object_entry(); }

  // Return a pointer to the derived Incremental_dynobj_entry object.
  // Return NULL for input entries that are not shared object files.
  Incremental_dynobj_entry*
  dynobj_entry()
  { return this->do_dynobj_entry(); }

  // Return a pointer to the derived Incremental_archive_entry object.
  // Return NULL for input entries that are not archive files.
  Incremental_archive_entry*
  archive_entry()
  { return this->do_archive_entry(); }

 protected:
  // Return the type of input file.
  virtual Incremental_input_type
  do_type() const = 0;

  // Return a pointer to the derived Incremental_script_entry object.
  // Return NULL for input entries that are not script files.
  virtual Incremental_script_entry*
  do_script_entry()
  { return NULL; }

  // Return a pointer to the derived Incremental_object_entry object.
  // Return NULL for input entries that are not object files.
  virtual Incremental_object_entry*
  do_object_entry()
  { return NULL; }

  // Return a pointer to the derived Incremental_dynobj_entry object.
  // Return NULL for input entries that are not shared object files.
  virtual Incremental_dynobj_entry*
  do_dynobj_entry()
  { return NULL; }

  // Return a pointer to the derived Incremental_archive_entry object.
  // Return NULL for input entries that are not archive files.
  virtual Incremental_archive_entry*
  do_archive_entry()
  { return NULL; }

 private:
  // Key of the filename string in the section stringtable.
  Stringpool::Key filename_key_;

  // Index of the entry in the output section.
  unsigned int file_index_;

  // Offset of the entry in the output section.
  unsigned int offset_;

  // Offset of the extra information in the output section.
  unsigned int info_offset_;

  // Serial number of the file in the argument list.
  unsigned int arg_serial_;

  // Last modification time of the file.
  Timespec mtime_;

  // TRUE if the file was found in a system directory.
  bool is_in_system_directory_;

  // TRUE if the file was linked with --as-needed.
  bool as_needed_;
};

// Information about a script input that will persist during the whole linker
// run.  Needed only during an incremental build to retrieve the input files
// added by this script.

class Script_info
{
 public:
  Script_info(const std::string& filename)
    : filename_(filename), input_file_index_(0),
      incremental_script_entry_(NULL)
  { }

  Script_info(const std::string& filename, unsigned int input_file_index)
    : filename_(filename), input_file_index_(input_file_index),
      incremental_script_entry_(NULL)
  { }

  // Store a pointer to the incremental information for this script.
  void
  set_incremental_info(Incremental_script_entry* entry)
  { this->incremental_script_entry_ = entry; }

  // Return the filename.
  const std::string&
  filename() const
  { return this->filename_; }

  // Return the input file index.
  unsigned int
  input_file_index() const
  { return this->input_file_index_; }

  // Return the pointer to the incremental information for this script.
  Incremental_script_entry*
  incremental_info() const
  { return this->incremental_script_entry_; }

 private:
  const std::string filename_;
  unsigned int input_file_index_;
  Incremental_script_entry* incremental_script_entry_;
};

// Class for recording input scripts.

class Incremental_script_entry : public Incremental_input_entry
{
 public:
  Incremental_script_entry(Stringpool::Key filename_key,
			   unsigned int arg_serial, Script_info* /*script*/,
			   Timespec mtime)
    : Incremental_input_entry(filename_key, arg_serial, mtime),
      objects_()
  { }

  // Add a member object to the archive.
  void
  add_object(Incremental_input_entry* obj_entry)
  {
    this->objects_.push_back(obj_entry);
  }

  // Return the number of objects included by this script.
  unsigned int
  get_object_count()
  { return this->objects_.size(); }

  // Return the Nth object.
  Incremental_input_entry*
  get_object(unsigned int n)
  {
    gold_assert(n < this->objects_.size());
    return this->objects_[n];
  }

 protected:
  virtual Incremental_input_type
  do_type() const
  { return INCREMENTAL_INPUT_SCRIPT; }

  // Return a pointer to the derived Incremental_script_entry object.
  virtual Incremental_script_entry*
  do_script_entry()
  { return this; }

 private:
  // Objects that have been included by this script.
  std::vector<Incremental_input_entry*> objects_;
};

// Class for recording input object files.

class Incremental_object_entry : public Incremental_input_entry
{
 public:
  Incremental_object_entry(Stringpool::Key filename_key, Object* obj,
			   unsigned int arg_serial, Timespec mtime)
    : Incremental_input_entry(filename_key, arg_serial, mtime), obj_(obj),
      is_member_(false), sections_(), groups_()
  { this->sections_.reserve(obj->shnum()); }

  // Get the object.
  Object*
  object() const
  { return this->obj_; }

  // Record that this object is an archive member.
  void
  set_is_member()
  { this->is_member_ = true; }

  // Return true if this object is an archive member.
  bool
  is_member() const
  { return this->is_member_; }

  // Add an input section.
  void
  add_input_section(unsigned int shndx, Stringpool::Key name_key, off_t sh_size)
  { this->sections_.push_back(Input_section(shndx, name_key, sh_size)); }

  // Return the number of input sections in this object.
  unsigned int
  get_input_section_count() const
  { return this->sections_.size(); }

  // Return the input section index for the Nth input section.
  Stringpool::Key
  get_input_section_index(unsigned int n) const
  { return this->sections_[n].shndx_; }

  // Return the stringpool key of the Nth input section.
  Stringpool::Key
  get_input_section_name_key(unsigned int n) const
  { return this->sections_[n].name_key_; }

  // Return the size of the Nth input section.
  off_t
  get_input_section_size(unsigned int n) const
  { return this->sections_[n].sh_size_; }

  // Add a kept COMDAT group.
  void
  add_comdat_group(Stringpool::Key signature_key)
  { this->groups_.push_back(signature_key); }

  // Return the number of COMDAT groups.
  unsigned int
  get_comdat_group_count() const
  { return this->groups_.size(); }

  // Return the stringpool key for the signature of the Nth comdat group.
  Stringpool::Key
  get_comdat_signature_key(unsigned int n) const
  { return this->groups_[n]; }

 protected:
  virtual Incremental_input_type
  do_type() const
  {
    return (this->is_member_
	    ? INCREMENTAL_INPUT_ARCHIVE_MEMBER
	    : INCREMENTAL_INPUT_OBJECT);
  }

  // Return a pointer to the derived Incremental_object_entry object.
  virtual Incremental_object_entry*
  do_object_entry()
  { return this; }

 private:
  // The object file itself.
  Object* obj_;

  // Whether this object is an archive member.
  bool is_member_;

  // Input sections.
  struct Input_section
  {
    Input_section(unsigned int shndx, Stringpool::Key name_key, off_t sh_size)
      : shndx_(shndx), name_key_(name_key), sh_size_(sh_size)
    { }
    unsigned int shndx_;
    Stringpool::Key name_key_;
    off_t sh_size_;
  };
  std::vector<Input_section> sections_;

  // COMDAT groups.
  std::vector<Stringpool::Key> groups_;
};

// Class for recording shared library input files.

class Incremental_dynobj_entry : public Incremental_input_entry
{
 public:
  Incremental_dynobj_entry(Stringpool::Key filename_key,
  			   Stringpool::Key soname_key, Object* obj,
			   unsigned int arg_serial, Timespec mtime)
    : Incremental_input_entry(filename_key, arg_serial, mtime),
      soname_key_(soname_key), obj_(obj)
  { }

  // Get the object.
  Object*
  object() const
  { return this->obj_; }

  // Get the stringpool key for the soname.
  Stringpool::Key
  get_soname_key() const
  { return this->soname_key_; }

 protected:
  virtual Incremental_input_type
  do_type() const
  { return INCREMENTAL_INPUT_SHARED_LIBRARY; }

  // Return a pointer to the derived Incremental_dynobj_entry object.
  virtual Incremental_dynobj_entry*
  do_dynobj_entry()
  { return this; }

 private:
  // Key of the soname string in the section stringtable.
  Stringpool::Key soname_key_;

  // The object file itself.
  Object* obj_;
};

// Class for recording archive library input files.

class Incremental_archive_entry : public Incremental_input_entry
{
 public:
  Incremental_archive_entry(Stringpool::Key filename_key,
			    unsigned int arg_serial, Timespec mtime)
    : Incremental_input_entry(filename_key, arg_serial, mtime), members_(),
      unused_syms_()
  { }

  // Add a member object to the archive.
  void
  add_object(Incremental_object_entry* obj_entry)
  {
    this->members_.push_back(obj_entry);
    obj_entry->set_is_member();
  }

  // Add an unused global symbol to the archive.
  void
  add_unused_global_symbol(Stringpool::Key symbol_key)
  { this->unused_syms_.push_back(symbol_key); }

  // Return the number of member objects included in the link.
  unsigned int
  get_member_count()
  { return this->members_.size(); }

  // Return the Nth member object.
  Incremental_object_entry*
  get_member(unsigned int n)
  { return this->members_[n]; }

  // Return the number of unused global symbols in this archive.
  unsigned int
  get_unused_global_symbol_count()
  { return this->unused_syms_.size(); }

  // Return the Nth unused global symbol.
  Stringpool::Key
  get_unused_global_symbol(unsigned int n)
  { return this->unused_syms_[n]; }

 protected:
  virtual Incremental_input_type
  do_type() const
  { return INCREMENTAL_INPUT_ARCHIVE; }

  // Return a pointer to the derived Incremental_archive_entry object.
  virtual Incremental_archive_entry*
  do_archive_entry()
  { return this; }

 private:
  // Members of the archive that have been included in the link.
  std::vector<Incremental_object_entry*> members_;

  // Unused global symbols from this archive.
  std::vector<Stringpool::Key> unused_syms_;
};

// This class contains the information needed during an incremental
// build about the inputs necessary to build the .gnu_incremental_inputs.

class Incremental_inputs
{
 public:
  typedef std::vector<Incremental_input_entry*> Input_list;

  Incremental_inputs()
    : inputs_(), command_line_(), command_line_key_(0),
      strtab_(new Stringpool()), current_object_(NULL),
      current_object_entry_(NULL), inputs_section_(NULL),
      symtab_section_(NULL), relocs_section_(NULL),
      reloc_count_(0)
  { }

  ~Incremental_inputs() { delete this->strtab_; }

  // Record the command line.
  void
  report_command_line(int argc, const char* const* argv);

  // Record the initial info for archive file ARCHIVE.
  void
  report_archive_begin(Library_base* arch, unsigned int arg_serial,
		       Script_info* script_info);

  // Record the final info for archive file ARCHIVE.
  void
  report_archive_end(Library_base* arch);

  // Record the info for object file OBJ.  If ARCH is not NULL,
  // attach the object file to the archive.
  void
  report_object(Object* obj, unsigned int arg_serial, Library_base* arch,
		Script_info* script_info);

  // Record an input section belonging to object file OBJ.
  void
  report_input_section(Object* obj, unsigned int shndx, const char* name,
		       off_t sh_size);

  // Record a kept COMDAT group belonging to object file OBJ.
  void
  report_comdat_group(Object* obj, const char* name);

  // Record the info for input script SCRIPT.
  void
  report_script(Script_info* script, unsigned int arg_serial,
		Timespec mtime);

  // Return the running count of incremental relocations.
  unsigned int
  get_reloc_count() const
  { return this->reloc_count_; }

  // Update the running count of incremental relocations.
  void
  set_reloc_count(unsigned int count)
  { this->reloc_count_ = count; }

  // Prepare for layout.  Called from Layout::finalize.
  void
  finalize();

  // Create the .gnu_incremental_inputs and related sections.
  void
  create_data_sections(Symbol_table* symtab);

  // Return the .gnu_incremental_inputs section.
  Output_section_data*
  inputs_section() const
  { return this->inputs_section_; }

  // Return the .gnu_incremental_symtab section.
  Output_data_space*
  symtab_section() const
  { return this->symtab_section_; }

  // Return the .gnu_incremental_relocs section.
  Output_data_space*
  relocs_section() const
  { return this->relocs_section_; }

  // Return the .gnu_incremental_got_plt section.
  Output_data_space*
  got_plt_section() const
  { return this->got_plt_section_; }

  // Return the .gnu_incremental_strtab stringpool.
  Stringpool*
  get_stringpool() const
  { return this->strtab_; }

  // Return the canonical form of the command line, as will be stored in
  // .gnu_incremental_strtab.
  const std::string&
  command_line() const
  { return this->command_line_; }

  // Return the stringpool key of the command line.
  Stringpool::Key
  command_line_key() const
  { return this->command_line_key_; }

  // Return the number of input files.
  int
  input_file_count() const
  { return this->inputs_.size(); }

  // Return the input files.
  const Input_list&
  input_files() const
  { return this->inputs_; }

  // Return the sh_entsize value for the .gnu_incremental_relocs section.
  unsigned int
  relocs_entsize() const;

 private:
  // The list of input files.
  Input_list inputs_;

  // Canonical form of the command line, as will be stored in
  // .gnu_incremental_strtab.
  std::string command_line_;

  // The key of the command line string in the string pool.
  Stringpool::Key command_line_key_;

  // The .gnu_incremental_strtab string pool associated with the
  // .gnu_incremental_inputs.
  Stringpool* strtab_;

  // Keep track of the object currently being processed.
  Object* current_object_;
  Incremental_object_entry* current_object_entry_;

  // The .gnu_incremental_inputs section.
  Output_section_data* inputs_section_;

  // The .gnu_incremental_symtab section.
  Output_data_space* symtab_section_;

  // The .gnu_incremental_relocs section.
  Output_data_space* relocs_section_;

  // The .gnu_incremental_got_plt section.
  Output_data_space* got_plt_section_;

  // Total count of incremental relocations.  Updated during Scan_relocs
  // phase at the completion of each object file.
  unsigned int reloc_count_;
};

// Reader class for global symbol info from an object file entry in
// the .gnu_incremental_inputs section.

template<bool big_endian>
class Incremental_global_symbol_reader
{
 private:
  typedef elfcpp::Swap<32, big_endian> Swap32;

 public:
  Incremental_global_symbol_reader(const unsigned char* p)
    : p_(p)
  { }

  unsigned int
  output_symndx() const
  { return Swap32::readval(this->p_); }

  unsigned int
  shndx() const
  { return Swap32::readval(this->p_ + 4); }

  unsigned int
  next_offset() const
  { return Swap32::readval(this->p_ + 8); }

  unsigned int
  reloc_count() const
  { return Swap32::readval(this->p_ + 12); }

  unsigned int
  reloc_offset() const
  { return Swap32::readval(this->p_ + 16); }

 private:
  // Base address of the symbol entry.
  const unsigned char* p_;
};

// Reader class for .gnu_incremental_inputs section.

template<int size, bool big_endian>
class Incremental_inputs_reader
{
 private:
  typedef elfcpp::Swap<size, big_endian> Swap;
  typedef elfcpp::Swap<16, big_endian> Swap16;
  typedef elfcpp::Swap<32, big_endian> Swap32;
  typedef elfcpp::Swap<64, big_endian> Swap64;

 public:
  // Size of the .gnu_incremental_inputs header.
  // (3 x 4-byte fields, plus 4 bytes padding.)
  static const unsigned int header_size = 16;
  // Size of an input file entry.
  // (2 x 4-byte fields, 1 x 12-byte field, 2 x 2-byte fields.)
  static const unsigned int input_entry_size = 24;
  // Size of the first part of the supplemental info block for
  // relocatable objects and archive members.
  // (7 x 4-byte fields, plus 4 bytes padding.)
  static const unsigned int object_info_size = 32;
  // Size of an input section entry.
  // (2 x 4-byte fields, 2 x address-sized fields.)
  static const unsigned int input_section_entry_size = 8 + 2 * size / 8;
  // Size of a global symbol entry in the supplemental info block.
  // (5 x 4-byte fields.)
  static const unsigned int global_sym_entry_size = 20;

  Incremental_inputs_reader()
    : p_(NULL), strtab_(NULL, 0), input_file_count_(0)
  { }

  Incremental_inputs_reader(const unsigned char* p,
			    const elfcpp::Elf_strtab& strtab)
    : p_(p), strtab_(strtab)
  { this->input_file_count_ = Swap32::readval(this->p_ + 4); }

  // Return the version number.
  unsigned int
  version() const
  { return Swap32::readval(this->p_); }

  // Return the count of input file entries.
  unsigned int
  input_file_count() const
  { return this->input_file_count_; }

  // Return the command line.
  const char*
  command_line() const
  {
    unsigned int offset = Swap32::readval(this->p_ + 8);
    return this->get_string(offset);
  }

  // Reader class for an input file entry and its supplemental info.
  class Incremental_input_entry_reader
  {
   private:
    static const unsigned int object_info_size =
	Incremental_inputs_reader<size, big_endian>::object_info_size;
    static const unsigned int input_section_entry_size =
	Incremental_inputs_reader<size, big_endian>::input_section_entry_size;
    static const unsigned int global_sym_entry_size =
	Incremental_inputs_reader<size, big_endian>::global_sym_entry_size;

   public:
    Incremental_input_entry_reader(const Incremental_inputs_reader* inputs,
				   unsigned int offset)
      : inputs_(inputs), offset_(offset)
    {
      this->info_offset_ = Swap32::readval(inputs->p_ + offset + 4);
      this->flags_ = Swap16::readval(this->inputs_->p_ + offset + 20);
    }

    // Return the filename.
    const char*
    filename() const
    {
      unsigned int offset = Swap32::readval(this->inputs_->p_ + this->offset_);
      return this->inputs_->get_string(offset);
    }

    // Return the argument serial number.
    unsigned int
    arg_serial() const
    {
      return Swap16::readval(this->inputs_->p_ + this->offset_ + 22);
    }

    // Return the timestamp.
    Timespec
    get_mtime() const
    {
      Timespec t;
      const unsigned char* p = this->inputs_->p_ + this->offset_ + 8;
      t.seconds = Swap64::readval(p);
      t.nanoseconds = Swap32::readval(p+8);
      return t;
    }

    // Return the type of input file.
    Incremental_input_type
    type() const
    { return static_cast<Incremental_input_type>(this->flags_ & 0xff); }

    // Return TRUE if the file was found in a system directory.
    bool
    is_in_system_directory() const
    { return (this->flags_ & INCREMENTAL_INPUT_IN_SYSTEM_DIR) != 0; }

    // Return TRUE if the file was linked with --as-needed.
    bool
    as_needed() const
    { return (this->flags_ & INCREMENTAL_INPUT_AS_NEEDED) != 0; }

    // Return the input section count -- for objects only.
    unsigned int
    get_input_section_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_);
    }

    // Return the soname -- for shared libraries only.
    const char*
    get_soname() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
      unsigned int offset = Swap32::readval(this->inputs_->p_
					    + this->info_offset_);
      return this->inputs_->get_string(offset);
    }

    // Return the offset of the supplemental info for symbol SYMNDX --
    // for objects only.
    unsigned int
    get_symbol_offset(unsigned int symndx) const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      unsigned int section_count = this->get_input_section_count();
      return (this->info_offset_
	      + this->object_info_size
	      + section_count * this->input_section_entry_size
	      + symndx * this->global_sym_entry_size);
    }

    // Return the global symbol count -- for objects & shared libraries only.
    unsigned int
    get_global_symbol_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER
		  || this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 4);
    }

    // Return the offset of the first local symbol -- for objects only.
    unsigned int
    get_local_symbol_offset() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 8);
    }

    // Return the local symbol count -- for objects only.
    unsigned int
    get_local_symbol_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 12);
    }

    // Return the index of the first dynamic relocation -- for objects only.
    unsigned int
    get_first_dyn_reloc() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 16);
    }

    // Return the dynamic relocation count -- for objects only.
    unsigned int
    get_dyn_reloc_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 20);
    }

    // Return the COMDAT group count -- for objects only.
    unsigned int
    get_comdat_group_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);

      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 24);
    }

    // Return the object count -- for scripts only.
    unsigned int
    get_object_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_SCRIPT);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_);
    }

    // Return the input file offset for object N -- for scripts only.
    unsigned int
    get_object_offset(unsigned int n) const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_SCRIPT);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_
			     + 4 + n * 4);
    }

    // Return the member count -- for archives only.
    unsigned int
    get_member_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_ARCHIVE);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_);
    }

    // Return the unused symbol count -- for archives only.
    unsigned int
    get_unused_symbol_count() const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_ARCHIVE);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 4);
    }

    // Return the input file offset for archive member N -- for archives only.
    unsigned int
    get_member_offset(unsigned int n) const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_ARCHIVE);
      return Swap32::readval(this->inputs_->p_ + this->info_offset_
			     + 8 + n * 4);
    }

    // Return the Nth unused global symbol -- for archives only.
    const char*
    get_unused_symbol(unsigned int n) const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_ARCHIVE);
      unsigned int member_count = this->get_member_count();
      unsigned int offset = Swap32::readval(this->inputs_->p_
					    + this->info_offset_ + 8
					    + member_count * 4
					    + n * 4);
      return this->inputs_->get_string(offset);
    }

    // Information about an input section.
    struct Input_section_info
    {
      const char* name;
      unsigned int output_shndx;
      off_t sh_offset;
      off_t sh_size;
    };

    // Return info about the Nth input section -- for objects only.
    Input_section_info
    get_input_section(unsigned int n) const
    {
      Input_section_info info;
      const unsigned char* p = (this->inputs_->p_
				+ this->info_offset_
				+ this->object_info_size
				+ n * this->input_section_entry_size);
      unsigned int name_offset = Swap32::readval(p);
      info.name = this->inputs_->get_string(name_offset);
      info.output_shndx = Swap32::readval(p + 4);
      info.sh_offset = Swap::readval(p + 8);
      info.sh_size = Swap::readval(p + 8 + size / 8);
      return info;
    }

    // Return info about the Nth global symbol -- for objects only.
    Incremental_global_symbol_reader<big_endian>
    get_global_symbol_reader(unsigned int n) const
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
		  || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);
      unsigned int section_count = this->get_input_section_count();
      const unsigned char* p = (this->inputs_->p_
				+ this->info_offset_
				+ this->object_info_size
				+ section_count * this->input_section_entry_size
				+ n * this->global_sym_entry_size);
      return Incremental_global_symbol_reader<big_endian>(p);
    }

    // Return the signature of the Nth comdat group -- for objects only.
    const char*
    get_comdat_group_signature(unsigned int n) const
    {
      unsigned int section_count = this->get_input_section_count();
      unsigned int symbol_count = this->get_global_symbol_count();
      const unsigned char* p = (this->inputs_->p_
				+ this->info_offset_
				+ this->object_info_size
				+ section_count * this->input_section_entry_size
				+ symbol_count * this->global_sym_entry_size
				+ n * 4);
      unsigned int name_offset = Swap32::readval(p);
      return this->inputs_->get_string(name_offset);
    }

    // Return the output symbol index for the Nth global symbol -- for shared
    // libraries only.  Sets *IS_DEF to TRUE if the symbol is defined in this
    // input file.  Sets *IS_COPY to TRUE if the symbol was copied from this
    // input file with a COPY relocation.
    unsigned int
    get_output_symbol_index(unsigned int n, bool* is_def, bool* is_copy)
    {
      gold_assert(this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
      const unsigned char* p = (this->inputs_->p_
				+ this->info_offset_ + 8
				+ n * 4);
      unsigned int output_symndx = Swap32::readval(p);
      unsigned int flags = output_symndx >> INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT;
      output_symndx &= ((1U << INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT) - 1);
      switch (flags)
	{
	  case INCREMENTAL_SHLIB_SYM_DEF:
	    *is_def = true;
	    *is_copy = false;
	    break;
	  case INCREMENTAL_SHLIB_SYM_COPY:
	    *is_def = true;
	    *is_copy = true;
	    break;
	  default:
	    *is_def = false;
	    *is_copy = false;
	}
      return output_symndx;
    }

   private:
    // The reader instance for the containing section.
    const Incremental_inputs_reader* inputs_;
    // The flags, including the type of input file.
    unsigned int flags_;
    // Section offset to the input file entry.
    unsigned int offset_;
    // Section offset to the supplemental info for the input file.
    unsigned int info_offset_;
  };

  // Return the offset of an input file entry given its index N.
  unsigned int
  input_file_offset(unsigned int n) const
  {
    gold_assert(n < this->input_file_count_);
    return this->header_size + n * this->input_entry_size;
  }

  // Return the index of an input file entry given its OFFSET.
  unsigned int
  input_file_index(unsigned int offset) const
  {
    int n = ((offset - this->header_size) / this->input_entry_size);
    gold_assert(input_file_offset(n) == offset);
    return n;
  }

  // Return a reader for the Nth input file entry.
  Incremental_input_entry_reader
  input_file(unsigned int n) const
  { return Incremental_input_entry_reader(this, this->input_file_offset(n)); }

  // Return a reader for the input file entry at OFFSET.
  Incremental_input_entry_reader
  input_file_at_offset(unsigned int offset) const
  {
    gold_assert(offset < (this->header_size
			  + this->input_file_count_ * this->input_entry_size));
    return Incremental_input_entry_reader(this, offset);
  }

  // Return a reader for the global symbol info at OFFSET.
  Incremental_global_symbol_reader<big_endian>
  global_symbol_reader_at_offset(unsigned int offset) const
  {
    const unsigned char* p = this->p_ + offset;
    return Incremental_global_symbol_reader<big_endian>(p);
  }

 private:
  // Lookup a string in the ELF string table.
  const char* get_string(unsigned int offset) const
  {
    const char* s;
    if (this->strtab_.get_c_string(offset, &s))
      return s;
    return NULL;
  }

  // Base address of the .gnu_incremental_inputs section.
  const unsigned char* p_;
  // The associated ELF string table.
  elfcpp::Elf_strtab strtab_;
  // The number of input file entries in this section.
  unsigned int input_file_count_;
};

// Reader class for the .gnu_incremental_symtab section.

template<bool big_endian>
class Incremental_symtab_reader
{
 public:
  Incremental_symtab_reader()
    : p_(NULL), len_(0)
  { }

  Incremental_symtab_reader(const unsigned char* p, off_t len)
    : p_(p), len_(len)
  { }

  // Return the count of symbols in this section.
  unsigned int
  symbol_count() const
  { return static_cast<unsigned int>(this->len_ / 4); }

  // Return the list head for symbol table entry N.
  unsigned int
  get_list_head(unsigned int n) const
  { return elfcpp::Swap<32, big_endian>::readval(this->p_ + 4 * n); }

 private:
  // Base address of the .gnu_incremental_relocs section.
  const unsigned char* p_;
  // Size of the section.
  off_t len_;
};

// Reader class for the .gnu_incremental_relocs section.

template<int size, bool big_endian>
class Incremental_relocs_reader
{
 private:
  // Size of each field.
  static const unsigned int field_size = size / 8;

 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
  typedef typename elfcpp::Elf_types<size>::Elf_Swxword Addend;

  // Size of each entry.
  static const unsigned int reloc_size = 8 + 2 * field_size;

  Incremental_relocs_reader()
    : p_(NULL), len_(0)
  { }

  Incremental_relocs_reader(const unsigned char* p, off_t len)
    : p_(p), len_(len)
  { }

  // Return the count of relocations in this section.
  unsigned int
  reloc_count() const
  { return static_cast<unsigned int>(this->len_ / reloc_size); }

  // Return the relocation type for relocation entry at offset OFF.
  unsigned int
  get_r_type(unsigned int off) const
  { return elfcpp::Swap<32, big_endian>::readval(this->p_ + off); }

  // Return the output section index for relocation entry at offset OFF.
  unsigned int
  get_r_shndx(unsigned int off) const
  { return elfcpp::Swap<32, big_endian>::readval(this->p_ + off + 4); }

  // Return the output section offset for relocation entry at offset OFF.
  Address
  get_r_offset(unsigned int off) const
  { return elfcpp::Swap<size, big_endian>::readval(this->p_ + off + 8); }

  // Return the addend for relocation entry at offset OFF.
  Addend
  get_r_addend(unsigned int off) const
  {
    return elfcpp::Swap<size, big_endian>::readval(this->p_ + off + 8
						   + this->field_size);
  }

  // Return a pointer to the relocation entry at offset OFF.
  const unsigned char*
  data(unsigned int off) const
  { return this->p_ + off; }

 private:
  // Base address of the .gnu_incremental_relocs section.
  const unsigned char* p_;
  // Size of the section.
  off_t len_;
};

// Reader class for the .gnu_incremental_got_plt section.

template<bool big_endian>
class Incremental_got_plt_reader
{
 public:
  Incremental_got_plt_reader()
    : p_(NULL), got_count_(0), got_desc_p_(NULL), plt_desc_p_(NULL)
  { }

  Incremental_got_plt_reader(const unsigned char* p) : p_(p)
  {
    this->got_count_ = elfcpp::Swap<32, big_endian>::readval(p);
    this->got_desc_p_ = p + 8 + ((this->got_count_ + 3) & ~3);
    this->plt_desc_p_ = this->got_desc_p_ + this->got_count_ * 8;
  }

  // Return the GOT entry count.
  unsigned int
  get_got_entry_count() const
  {
    return this->got_count_;
  }

  // Return the PLT entry count.
  unsigned int
  get_plt_entry_count() const
  {
    return elfcpp::Swap<32, big_endian>::readval(this->p_ + 4);
  }

  // Return the GOT type for GOT entry N.
  unsigned int
  get_got_type(unsigned int n)
  {
    return this->p_[8 + n];
  }

  // Return the symbol index for GOT entry N.
  unsigned int
  get_got_symndx(unsigned int n)
  {
    return elfcpp::Swap<32, big_endian>::readval(this->got_desc_p_ + n * 8);
  }

  // Return the input file index for GOT entry N.
  unsigned int
  get_got_input_index(unsigned int n)
  {
    return elfcpp::Swap<32, big_endian>::readval(this->got_desc_p_ + n * 8 + 4);
  }

  // Return the PLT descriptor for PLT entry N.
  unsigned int
  get_plt_desc(unsigned int n)
  {
    return elfcpp::Swap<32, big_endian>::readval(this->plt_desc_p_ + n * 4);
  }

 private:
  // Base address of the .gnu_incremental_got_plt section.
  const unsigned char* p_;
  // GOT entry count.
  unsigned int got_count_;
  // Base address of the GOT descriptor array.
  const unsigned char* got_desc_p_;
  // Base address of the PLT descriptor array.
  const unsigned char* plt_desc_p_;
};

// An object representing the ELF file we edit during an incremental build.
// Similar to Object or Dynobj, but operates on Output_file and contains
// methods to support incremental updating. This is the abstract parent class
// implemented in Sized_incremental_binary<size, big_endian> for a specific
// endianness and size.

class Incremental_binary
{
 public:
  Incremental_binary(Output_file* output, Target* /*target*/)
    : input_args_map_(), library_map_(), script_map_(),
      output_(output)
  { }

  virtual
  ~Incremental_binary()
  { }

  // Check the .gnu_incremental_inputs section to see whether an incremental
  // build is possible.
  bool
  check_inputs(const Command_line& cmdline,
	       Incremental_inputs* incremental_inputs)
  { return this->do_check_inputs(cmdline, incremental_inputs); }

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

  // Proxy class for a sized Incremental_input_entry_reader.

  class Input_reader
  {
   public:
    Input_reader()
    { }

    virtual
    ~Input_reader()
    { }

    const char*
    filename() const
    { return this->do_filename(); }

    Timespec
    get_mtime() const
    { return this->do_get_mtime(); }

    Incremental_input_type
    type() const
    { return this->do_type(); }

    unsigned int
    arg_serial() const
    { return this->do_arg_serial(); }

    unsigned int
    get_unused_symbol_count() const
    { return this->do_get_unused_symbol_count(); }

    const char*
    get_unused_symbol(unsigned int n) const
    { return this->do_get_unused_symbol(n); }

   protected:
    virtual const char*
    do_filename() const = 0;

    virtual Timespec
    do_get_mtime() const = 0;

    virtual Incremental_input_type
    do_type() const = 0;

    virtual unsigned int
    do_arg_serial() const = 0;

    virtual unsigned int
    do_get_unused_symbol_count() const = 0;

    virtual const char*
    do_get_unused_symbol(unsigned int n) const = 0;
  };

  // Return the number of input files.
  unsigned int
  input_file_count() const
  { return this->do_input_file_count(); }

  // Return an Input_reader for input file N.
  const Input_reader*
  get_input_reader(unsigned int n) const
  { return this->do_get_input_reader(n); }

  // Return TRUE if the input file N has changed since the last link.
  bool
  file_has_changed(unsigned int n) const
  { return this->do_file_has_changed(n); }

  // Return the Input_argument for input file N.  Returns NULL if
  // the Input_argument is not available.
  const Input_argument*
  get_input_argument(unsigned int n) const
  {
    const Input_reader* input_file = this->do_get_input_reader(n);
    unsigned int arg_serial = input_file->arg_serial();
    if (arg_serial == 0 || arg_serial > this->input_args_map_.size())
      return NULL;
    return this->input_args_map_[arg_serial - 1];
  }

  // Return an Incremental_library for the given input file.
  Incremental_library*
  get_library(unsigned int n) const
  { return this->library_map_[n]; }

  // Return a Script_info for the given input file.
  Script_info*
  get_script_info(unsigned int n) const
  { return this->script_map_[n]; }

  // Initialize the layout of the output file based on the existing
  // output file.
  void
  init_layout(Layout* layout)
  { this->do_init_layout(layout); }

  // Mark regions of the input file that must be kept unchanged.
  void
  reserve_layout(unsigned int input_file_index)
  { this->do_reserve_layout(input_file_index); }

  // Process the GOT and PLT entries from the existing output file.
  void
  process_got_plt(Symbol_table* symtab, Layout* layout)
  { this->do_process_got_plt(symtab, layout); }

  // Emit COPY relocations from the existing output file.
  void
  emit_copy_relocs(Symbol_table* symtab)
  { this->do_emit_copy_relocs(symtab); }

  // Apply incremental relocations for symbols whose values have changed.
  void
  apply_incremental_relocs(const Symbol_table* symtab, Layout* layout,
			   Output_file* of)
  { this->do_apply_incremental_relocs(symtab, layout, of); }

  // Functions and types for the elfcpp::Elf_file interface.  This
  // permit us to use Incremental_binary 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 Output_file::get_output_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->output_->get_input_view(file_offset, data_size)); }

  // 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)
    { }

    Location()
      : file_offset(0), data_size(0)
    { }
  };

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

  // Return the Output_file.
  Output_file*
  output_file()
  { return this->output_; }

 protected:
  // Check the .gnu_incremental_inputs section to see whether an incremental
  // build is possible.
  virtual bool
  do_check_inputs(const Command_line& cmdline,
		  Incremental_inputs* incremental_inputs) = 0;

  // Return TRUE if input file N has changed since the last incremental link.
  virtual bool
  do_file_has_changed(unsigned int n) const = 0;

  // Initialize the layout of the output file based on the existing
  // output file.
  virtual void
  do_init_layout(Layout* layout) = 0;

  // Mark regions of the input file that must be kept unchanged.
  virtual void
  do_reserve_layout(unsigned int input_file_index) = 0;

  // Process the GOT and PLT entries from the existing output file.
  virtual void
  do_process_got_plt(Symbol_table* symtab, Layout* layout) = 0;

  // Emit COPY relocations from the existing output file.
  virtual void
  do_emit_copy_relocs(Symbol_table* symtab) = 0;

  // Apply incremental relocations for symbols whose values have changed.
  virtual void
  do_apply_incremental_relocs(const Symbol_table*, Layout*, Output_file*) = 0;

  virtual unsigned int
  do_input_file_count() const = 0;

  virtual const Input_reader*
  do_get_input_reader(unsigned int) const = 0;

  // Map from input file index to Input_argument.
  std::vector<const Input_argument*> input_args_map_;
  // Map from an input file index to an Incremental_library.
  std::vector<Incremental_library*> library_map_;
  // Map from an input file index to a Script_info.
  std::vector<Script_info*> script_map_;

 private:
  // Edited output file object.
  Output_file* output_;
};

template<int size, bool big_endian>
class Sized_relobj_incr;

template<int size, bool big_endian>
class Sized_incremental_binary : public Incremental_binary
{
 public:
  Sized_incremental_binary(Output_file* output,
                           const elfcpp::Ehdr<size, big_endian>& ehdr,
                           Target* target)
    : Incremental_binary(output, target), elf_file_(this, ehdr),
      input_objects_(), section_map_(), symbol_map_(), copy_relocs_(),
      main_symtab_loc_(), main_strtab_loc_(), has_incremental_info_(false),
      inputs_reader_(), symtab_reader_(), relocs_reader_(), got_plt_reader_(),
      input_entry_readers_()
  { this->setup_readers(); }

  // Returns TRUE if the file contains incremental info.
  bool
  has_incremental_info() const
  { return this->has_incremental_info_; }

  // Record a pointer to the object for input file N.
  void
  set_input_object(unsigned int n,
		   Sized_relobj_incr<size, big_endian>* obj)
  { this->input_objects_[n] = obj; }

  // Return a pointer to the object for input file N.
  Sized_relobj_incr<size, big_endian>*
  input_object(unsigned int n) const
  {
    gold_assert(n < this->input_objects_.size());
    return this->input_objects_[n];
  }

  // Return the Output_section for section index SHNDX.
  Output_section*
  output_section(unsigned int shndx)
  { return this->section_map_[shndx]; }

  // Map a symbol table entry from the base file to the output symbol table.
  // SYMNDX is relative to the first forced-local or global symbol in the
  // input file symbol table.
  void
  add_global_symbol(unsigned int symndx, Symbol* gsym)
  { this->symbol_map_[symndx] = gsym; }

  // Map a symbol table entry from the base file to the output symbol table.
  // SYMNDX is relative to the first forced-local or global symbol in the
  // input file symbol table.
  Symbol*
  global_symbol(unsigned int symndx) const
  { return this->symbol_map_[symndx]; }

  // Add a COPY relocation for a global symbol.
  void
  add_copy_reloc(Symbol* gsym, Output_section* os, off_t offset)
  { this->copy_relocs_.push_back(Copy_reloc(gsym, os, offset)); }

  // Readers for the incremental info sections.

  const Incremental_inputs_reader<size, big_endian>&
  inputs_reader() const
  { return this->inputs_reader_; }

  const Incremental_symtab_reader<big_endian>&
  symtab_reader() const
  { return this->symtab_reader_; }

  const Incremental_relocs_reader<size, big_endian>&
  relocs_reader() const
  { return this->relocs_reader_; }

  const Incremental_got_plt_reader<big_endian>&
  got_plt_reader() const
  { return this->got_plt_reader_; }

  void
  get_symtab_view(View* symtab_view, unsigned int* sym_count,
		  elfcpp::Elf_strtab* strtab);

 protected:
  typedef Incremental_inputs_reader<size, big_endian> Inputs_reader;
  typedef typename Inputs_reader::Incremental_input_entry_reader
      Input_entry_reader;

  virtual bool
  do_check_inputs(const Command_line& cmdline,
		  Incremental_inputs* incremental_inputs);

  // Return TRUE if input file N has changed since the last incremental link.
  virtual bool
  do_file_has_changed(unsigned int n) const;

  // Initialize the layout of the output file based on the existing
  // output file.
  virtual void
  do_init_layout(Layout* layout);

  // Mark regions of the input file that must be kept unchanged.
  virtual void
  do_reserve_layout(unsigned int input_file_index);

  // Process the GOT and PLT entries from the existing output file.
  virtual void
  do_process_got_plt(Symbol_table* symtab, Layout* layout);

  // Emit COPY relocations from the existing output file.
  virtual void
  do_emit_copy_relocs(Symbol_table* symtab);

  // Apply incremental relocations for symbols whose values have changed.
  virtual void
  do_apply_incremental_relocs(const Symbol_table* symtab, Layout* layout,
			      Output_file* of);

  // Proxy class for a sized Incremental_input_entry_reader.

  class Sized_input_reader : public Input_reader
  {
   public:
    Sized_input_reader(Input_entry_reader r)
      : Input_reader(), reader_(r)
    { }

    virtual
    ~Sized_input_reader()
    { }

   private:
    const char*
    do_filename() const
    { return this->reader_.filename(); }

    Timespec
    do_get_mtime() const
    { return this->reader_.get_mtime(); }

    Incremental_input_type
    do_type() const
    { return this->reader_.type(); }

    unsigned int
    do_arg_serial() const
    { return this->reader_.arg_serial(); }

    unsigned int
    do_get_unused_symbol_count() const
    { return this->reader_.get_unused_symbol_count(); }

    const char*
    do_get_unused_symbol(unsigned int n) const
    { return this->reader_.get_unused_symbol(n); }

    Input_entry_reader reader_;
  };

  virtual unsigned int
  do_input_file_count() const
  { return this->inputs_reader_.input_file_count(); }

  virtual const Input_reader*
  do_get_input_reader(unsigned int n) const
  {
    gold_assert(n < this->input_entry_readers_.size());
    return &this->input_entry_readers_[n];
  }

 private:
  // List of symbols that need COPY relocations.
  struct Copy_reloc
  {
    Copy_reloc(Symbol* sym, Output_section* os, off_t off)
      : symbol(sym), output_section(os), offset(off)
    { }

    // The global symbol to copy.
    Symbol* symbol;
    // The output section into which the symbol was copied.
    Output_section* output_section;
    // The offset within that output section.
    off_t offset;
  };
  typedef std::vector<Copy_reloc> Copy_relocs;

  bool
  find_incremental_inputs_sections(unsigned int* p_inputs_shndx,
				   unsigned int* p_symtab_shndx,
				   unsigned int* p_relocs_shndx,
				   unsigned int* p_got_plt_shndx,
				   unsigned int* p_strtab_shndx);

  void
  setup_readers();

  // Output as an ELF file.
  elfcpp::Elf_file<size, big_endian, Incremental_binary> elf_file_;

  // Vector of pointers to the input objects for the unchanged files.
  // For replaced files, the corresponding pointer is NULL.
  std::vector<Sized_relobj_incr<size, big_endian>*> input_objects_;

  // Map section index to an Output_section in the updated layout.
  std::vector<Output_section*> section_map_;

  // Map global symbols from the input file to the symbol table.
  std::vector<Symbol*> symbol_map_;

  // List of symbols that need COPY relocations.
  Copy_relocs copy_relocs_;

  // Locations of the main symbol table and symbol string table.
  Location main_symtab_loc_;
  Location main_strtab_loc_;

  // Readers for the incremental info sections.
  bool has_incremental_info_;
  Incremental_inputs_reader<size, big_endian> inputs_reader_;
  Incremental_symtab_reader<big_endian> symtab_reader_;
  Incremental_relocs_reader<size, big_endian> relocs_reader_;
  Incremental_got_plt_reader<big_endian> got_plt_reader_;
  std::vector<Sized_input_reader> input_entry_readers_;
};

// An incremental Relobj.  This class represents a relocatable object
// that has not changed since the last incremental link, and whose contents
// can be used directly from the base file.

template<int size, bool big_endian>
class Sized_relobj_incr : 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;

  Sized_relobj_incr(const std::string& name,
		    Sized_incremental_binary<size, big_endian>* ibase,
		    unsigned int input_file_index);

 private:
  // For convenience.
  typedef Sized_relobj_incr<size, big_endian> This;
  static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;

  typedef typename Sized_relobj<size, big_endian>::Output_sections
      Output_sections;
  typedef Incremental_inputs_reader<size, big_endian> Inputs_reader;
  typedef typename Inputs_reader::Incremental_input_entry_reader
      Input_entry_reader;

  // A local symbol.
  struct Local_symbol
  {
    Local_symbol(const char* name_, Address value_, unsigned int size_,
		 unsigned int shndx_, unsigned int type_,
		 bool needs_dynsym_entry_)
      : st_value(value_), name(name_), st_size(size_), st_shndx(shndx_),
	st_type(type_), output_dynsym_index(0),
	needs_dynsym_entry(needs_dynsym_entry_)
    { }
    // The symbol value.
    Address st_value;
    // The symbol name.  This points to the stringpool entry.
    const char* name;
    // The symbol size.
    unsigned int st_size;
    // The output section index.
    unsigned int st_shndx : 28;
    // The symbol type.
    unsigned int st_type : 4;
    // The index of the symbol in the output dynamic symbol table.
    unsigned int output_dynsym_index : 31;
    // TRUE if the symbol needs to appear in the dynamic symbol table.
    unsigned int needs_dynsym_entry : 1;
  };

  // Return TRUE if this is an incremental (unchanged) input file.
  bool
  do_is_incremental() const
  { return true; }

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

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

  // 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);

  // Get the size of a section.
  uint64_t
  do_section_size(unsigned int shndx);

  // Get the name of a section.
  std::string
  do_section_name(unsigned int shndx) const;

  // Return a view of the contents of a section.
  const unsigned char*
  do_section_contents(unsigned int shndx, section_size_type* plen,
		      bool 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 section type.
  unsigned int
  do_section_type(unsigned int shndx);

  // Return the section link field.
  unsigned int
  do_section_link(unsigned int shndx);

  // Return the section link field.
  unsigned int
  do_section_info(unsigned int shndx);

  // Return the section alignment.
  uint64_t
  do_section_addralign(unsigned int 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 global symbols.
  const Symbols*
  do_get_global_symbols() const
  { return &this->symbols_; }

  // Return the value of a local symbol.
  uint64_t
  do_local_symbol_value(unsigned int, uint64_t) const
  { gold_unreachable(); }

  unsigned int
  do_local_plt_offset(unsigned int) const
  { gold_unreachable(); }

  bool
  do_local_is_tls(unsigned int) const
  { gold_unreachable(); }

  // 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->local_symbol_count_; }

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

  // 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);

  // Set the offset of a section.
  void
  do_set_section_offset(unsigned int shndx, uint64_t off);

  // The Incremental_binary base file.
  Sized_incremental_binary<size, big_endian>* ibase_;
  // The index of the object in the input file list.
  unsigned int input_file_index_;
  // The reader for the input file.
  Input_entry_reader input_reader_;
  // The number of local symbols.
  unsigned int local_symbol_count_;
  // The number of local symbols which go into the output file's dynamic
  // symbol table.
  unsigned int output_local_dynsym_count_;
  // This starting symbol index in the output symbol table.
  unsigned int local_symbol_index_;
  // The file offset for local symbols in the output symbol table.
  unsigned int local_symbol_offset_;
  // The file offset for local symbols in the output symbol table.
  unsigned int local_dynsym_offset_;
  // The entries in the symbol table for the external symbols.
  Symbols symbols_;
  // Number of symbols defined in object file itself.
  size_t defined_count_;
  // The offset of the first incremental relocation for this object.
  unsigned int incr_reloc_offset_;
  // The number of incremental relocations for this object.
  unsigned int incr_reloc_count_;
  // The index of the first incremental relocation for this object in the
  // updated output file.
  unsigned int incr_reloc_output_index_;
  // A copy of the incremental relocations from this object.
  unsigned char* incr_relocs_;
  // The local symbols.
  std::vector<Local_symbol> local_symbols_;
};

// An incremental Dynobj.  This class represents a shared object that has
// not changed since the last incremental link, and whose contents can be
// used directly from the base file.

template<int size, bool big_endian>
class Sized_incr_dynobj : public Dynobj
{
 public:
  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;

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

  Sized_incr_dynobj(const std::string& name,
		    Sized_incremental_binary<size, big_endian>* ibase,
		    unsigned int input_file_index);

 private:
  typedef Incremental_inputs_reader<size, big_endian> Inputs_reader;
  typedef typename Inputs_reader::Incremental_input_entry_reader
      Input_entry_reader;

  // Return TRUE if this is an incremental (unchanged) input file.
  bool
  do_is_incremental() const
  { return true; }

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

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

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

  // 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);

  // 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;

  // Get the size of a section.
  uint64_t
  do_section_size(unsigned int shndx);

  // Get the name of a section.
  std::string
  do_section_name(unsigned int shndx) const;

  // Return a view of the contents of a section.
  const unsigned char*
  do_section_contents(unsigned int shndx, section_size_type* plen,
		      bool 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 section type.
  unsigned int
  do_section_type(unsigned int shndx);

  // Return the section link field.
  unsigned int
  do_section_link(unsigned int shndx);

  // Return the section link field.
  unsigned int
  do_section_info(unsigned int shndx);

  // Return the section alignment.
  uint64_t
  do_section_addralign(unsigned int 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 global symbols.
  const Symbols*
  do_get_global_symbols() const
  { return &this->symbols_; }

  // The Incremental_binary base file.
  Sized_incremental_binary<size, big_endian>* ibase_;
  // The index of the object in the input file list.
  unsigned int input_file_index_;
  // The reader for the input file.
  Input_entry_reader input_reader_;
  // The entries in the symbol table for the external symbols.
  Symbols symbols_;
  // Number of symbols defined in object file itself.
  size_t defined_count_;
};

// Allocate an incremental object of the appropriate size and endianness.
extern Object*
make_sized_incremental_object(
    Incremental_binary* base,
    unsigned int input_file_index,
    Incremental_input_type input_type,
    const Incremental_binary::Input_reader* input_reader);

// This class represents an Archive library (or --start-lib/--end-lib group)
// that has not changed since the last incremental link.  Its contents come
// from the incremental inputs entry in the base file.

class Incremental_library : public Library_base
{
 public:
  Incremental_library(const char* filename, unsigned int input_file_index,
		      const Incremental_binary::Input_reader* input_reader)
    : Library_base(NULL), filename_(filename),
      input_file_index_(input_file_index), input_reader_(input_reader),
      unused_symbols_(), is_reported_(false)
  { }

  // Return the input file index.
  unsigned int
  input_file_index() const
  { return this->input_file_index_; }

  // Return the serial number of the input file.
  unsigned int
  arg_serial() const
  { return this->input_reader_->arg_serial(); }

  // Copy the unused symbols from the incremental input info.
  // We need to do this because we may be overwriting the incremental
  // input info in the base file before we write the new incremental
  // info.
  void
  copy_unused_symbols();

  // Return FALSE on the first call to indicate that the library needs
  // to be recorded; return TRUE subsequently.
  bool
  is_reported()
  {
    bool was_reported = this->is_reported_;
    is_reported_ = true;
    return was_reported;
  }

 private:
  typedef std::vector<std::string> Symbol_list;

  // The file name.
  const std::string&
  do_filename() const
  { return this->filename_; }

  // Return the modification time of the archive file.
  Timespec
  do_get_mtime()
  { return this->input_reader_->get_mtime(); }

  // Iterator for unused global symbols in the library.
  void
  do_for_all_unused_symbols(Symbol_visitor_base* v) const;

  // The name of the library.
  std::string filename_;
  // The input file index of this library.
  unsigned int input_file_index_;
  // A reader for the incremental input information.
  const Incremental_binary::Input_reader* input_reader_;
  // List of unused symbols defined in this library.
  Symbol_list unused_symbols_;
  // TRUE when this library has been reported to the new incremental info.
  bool is_reported_;
};

} // End namespace gold.

#endif // !defined(GOLD_INCREMENTAL_H)