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
|
// symtab.h -- the gold symbol table -*- C++ -*-
// Copyright 2006, 2007, 2008, 2009, 2010, 2011 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.
// Symbol_table
// The symbol table.
#ifndef GOLD_SYMTAB_H
#define GOLD_SYMTAB_H
#include <string>
#include <utility>
#include <vector>
#include "elfcpp.h"
#include "parameters.h"
#include "stringpool.h"
#include "object.h"
namespace gold
{
class Mapfile;
class Object;
class Relobj;
template<int size, bool big_endian>
class Sized_relobj_file;
template<int size, bool big_endian>
class Sized_pluginobj;
class Dynobj;
template<int size, bool big_endian>
class Sized_dynobj;
template<int size, bool big_endian>
class Sized_incrobj;
class Versions;
class Version_script_info;
class Input_objects;
class Output_data;
class Output_section;
class Output_segment;
class Output_file;
class Output_symtab_xindex;
class Garbage_collection;
class Icf;
// The base class of an entry in the symbol table. The symbol table
// can have a lot of entries, so we don't want this class too big.
// Size dependent fields can be found in the template class
// Sized_symbol. Targets may support their own derived classes.
class Symbol
{
public:
// Because we want the class to be small, we don't use any virtual
// functions. But because symbols can be defined in different
// places, we need to classify them. This enum is the different
// sources of symbols we support.
enum Source
{
// Symbol defined in a relocatable or dynamic input file--this is
// the most common case.
FROM_OBJECT,
// Symbol defined in an Output_data, a special section created by
// the target.
IN_OUTPUT_DATA,
// Symbol defined in an Output_segment, with no associated
// section.
IN_OUTPUT_SEGMENT,
// Symbol value is constant.
IS_CONSTANT,
// Symbol is undefined.
IS_UNDEFINED
};
// When the source is IN_OUTPUT_SEGMENT, we need to describe what
// the offset means.
enum Segment_offset_base
{
// From the start of the segment.
SEGMENT_START,
// From the end of the segment.
SEGMENT_END,
// From the filesz of the segment--i.e., after the loaded bytes
// but before the bytes which are allocated but zeroed.
SEGMENT_BSS
};
// Return the symbol name.
const char*
name() const
{ return this->name_; }
// Return the (ANSI) demangled version of the name, if
// parameters.demangle() is true. Otherwise, return the name. This
// is intended to be used only for logging errors, so it's not
// super-efficient.
std::string
demangled_name() const;
// Return the symbol version. This will return NULL for an
// unversioned symbol.
const char*
version() const
{ return this->version_; }
// Return whether this version is the default for this symbol name
// (eg, "foo@@V2" is a default version; "foo@V1" is not). Only
// meaningful for versioned symbols.
bool
is_default() const
{
gold_assert(this->version_ != NULL);
return this->is_def_;
}
// Set that this version is the default for this symbol name.
void
set_is_default()
{ this->is_def_ = true; }
// Return the symbol's name as name@version (or name@@version).
std::string
versioned_name() const;
// Return the symbol source.
Source
source() const
{ return this->source_; }
// Return the object with which this symbol is associated.
Object*
object() const
{
gold_assert(this->source_ == FROM_OBJECT);
return this->u_.from_object.object;
}
// Return the index of the section in the input relocatable or
// dynamic object file.
unsigned int
shndx(bool* is_ordinary) const
{
gold_assert(this->source_ == FROM_OBJECT);
*is_ordinary = this->is_ordinary_shndx_;
return this->u_.from_object.shndx;
}
// Return the output data section with which this symbol is
// associated, if the symbol was specially defined with respect to
// an output data section.
Output_data*
output_data() const
{
gold_assert(this->source_ == IN_OUTPUT_DATA);
return this->u_.in_output_data.output_data;
}
// If this symbol was defined with respect to an output data
// section, return whether the value is an offset from end.
bool
offset_is_from_end() const
{
gold_assert(this->source_ == IN_OUTPUT_DATA);
return this->u_.in_output_data.offset_is_from_end;
}
// Return the output segment with which this symbol is associated,
// if the symbol was specially defined with respect to an output
// segment.
Output_segment*
output_segment() const
{
gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
return this->u_.in_output_segment.output_segment;
}
// If this symbol was defined with respect to an output segment,
// return the offset base.
Segment_offset_base
offset_base() const
{
gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
return this->u_.in_output_segment.offset_base;
}
// Return the symbol binding.
elfcpp::STB
binding() const
{ return this->binding_; }
// Return the symbol type.
elfcpp::STT
type() const
{ return this->type_; }
// Return true for function symbol.
bool
is_func() const
{
return (this->type_ == elfcpp::STT_FUNC
|| this->type_ == elfcpp::STT_GNU_IFUNC);
}
// Return the symbol visibility.
elfcpp::STV
visibility() const
{ return this->visibility_; }
// Set the visibility.
void
set_visibility(elfcpp::STV visibility)
{ this->visibility_ = visibility; }
// Override symbol visibility.
void
override_visibility(elfcpp::STV);
// Set whether the symbol was originally a weak undef or a regular undef
// when resolved by a dynamic def.
inline void
set_undef_binding(elfcpp::STB bind)
{
if (!this->undef_binding_set_ || this->undef_binding_weak_)
{
this->undef_binding_weak_ = bind == elfcpp::STB_WEAK;
this->undef_binding_set_ = true;
}
}
// Return TRUE if a weak undef was resolved by a dynamic def.
inline bool
is_undef_binding_weak() const
{ return this->undef_binding_weak_; }
// Return the non-visibility part of the st_other field.
unsigned char
nonvis() const
{ return this->nonvis_; }
// Return whether this symbol is a forwarder. This will never be
// true of a symbol found in the hash table, but may be true of
// symbol pointers attached to object files.
bool
is_forwarder() const
{ return this->is_forwarder_; }
// Mark this symbol as a forwarder.
void
set_forwarder()
{ this->is_forwarder_ = true; }
// Return whether this symbol has an alias in the weak aliases table
// in Symbol_table.
bool
has_alias() const
{ return this->has_alias_; }
// Mark this symbol as having an alias.
void
set_has_alias()
{ this->has_alias_ = true; }
// Return whether this symbol needs an entry in the dynamic symbol
// table.
bool
needs_dynsym_entry() const
{
return (this->needs_dynsym_entry_
|| (this->in_reg()
&& this->in_dyn()
&& this->is_externally_visible()));
}
// Mark this symbol as needing an entry in the dynamic symbol table.
void
set_needs_dynsym_entry()
{ this->needs_dynsym_entry_ = true; }
// Return whether this symbol should be added to the dynamic symbol
// table.
bool
should_add_dynsym_entry(Symbol_table*) const;
// Return whether this symbol has been seen in a regular object.
bool
in_reg() const
{ return this->in_reg_; }
// Mark this symbol as having been seen in a regular object.
void
set_in_reg()
{ this->in_reg_ = true; }
// Return whether this symbol has been seen in a dynamic object.
bool
in_dyn() const
{ return this->in_dyn_; }
// Mark this symbol as having been seen in a dynamic object.
void
set_in_dyn()
{ this->in_dyn_ = true; }
// Return whether this symbol has been seen in a real ELF object.
// (IN_REG will return TRUE if the symbol has been seen in either
// a real ELF object or an object claimed by a plugin.)
bool
in_real_elf() const
{ return this->in_real_elf_; }
// Mark this symbol as having been seen in a real ELF object.
void
set_in_real_elf()
{ this->in_real_elf_ = true; }
// Return whether this symbol was defined in a section that was
// discarded from the link. This is used to control some error
// reporting.
bool
is_defined_in_discarded_section() const
{ return this->is_defined_in_discarded_section_; }
// Mark this symbol as having been defined in a discarded section.
void
set_is_defined_in_discarded_section()
{ this->is_defined_in_discarded_section_ = true; }
// Return the index of this symbol in the output file symbol table.
// A value of -1U means that this symbol is not going into the
// output file. This starts out as zero, and is set to a non-zero
// value by Symbol_table::finalize. It is an error to ask for the
// symbol table index before it has been set.
unsigned int
symtab_index() const
{
gold_assert(this->symtab_index_ != 0);
return this->symtab_index_;
}
// Set the index of the symbol in the output file symbol table.
void
set_symtab_index(unsigned int index)
{
gold_assert(index != 0);
this->symtab_index_ = index;
}
// Return whether this symbol already has an index in the output
// file symbol table.
bool
has_symtab_index() const
{ return this->symtab_index_ != 0; }
// Return the index of this symbol in the dynamic symbol table. A
// value of -1U means that this symbol is not going into the dynamic
// symbol table. This starts out as zero, and is set to a non-zero
// during Layout::finalize. It is an error to ask for the dynamic
// symbol table index before it has been set.
unsigned int
dynsym_index() const
{
gold_assert(this->dynsym_index_ != 0);
return this->dynsym_index_;
}
// Set the index of the symbol in the dynamic symbol table.
void
set_dynsym_index(unsigned int index)
{
gold_assert(index != 0);
this->dynsym_index_ = index;
}
// Return whether this symbol already has an index in the dynamic
// symbol table.
bool
has_dynsym_index() const
{ return this->dynsym_index_ != 0; }
// Return whether this symbol has an entry in the GOT section.
// For a TLS symbol, this GOT entry will hold its tp-relative offset.
bool
has_got_offset(unsigned int got_type) const
{ return this->got_offsets_.get_offset(got_type) != -1U; }
// Return the offset into the GOT section of this symbol.
unsigned int
got_offset(unsigned int got_type) const
{
unsigned int got_offset = this->got_offsets_.get_offset(got_type);
gold_assert(got_offset != -1U);
return got_offset;
}
// Set the GOT offset of this symbol.
void
set_got_offset(unsigned int got_type, unsigned int got_offset)
{ this->got_offsets_.set_offset(got_type, got_offset); }
// Return the GOT offset list.
const Got_offset_list*
got_offset_list() const
{ return this->got_offsets_.get_list(); }
// Return whether this symbol has an entry in the PLT section.
bool
has_plt_offset() const
{ return this->plt_offset_ != -1U; }
// Return the offset into the PLT section of this symbol.
unsigned int
plt_offset() const
{
gold_assert(this->has_plt_offset());
return this->plt_offset_;
}
// Set the PLT offset of this symbol.
void
set_plt_offset(unsigned int plt_offset)
{
gold_assert(plt_offset != -1U);
this->plt_offset_ = plt_offset;
}
// Return whether this dynamic symbol needs a special value in the
// dynamic symbol table.
bool
needs_dynsym_value() const
{ return this->needs_dynsym_value_; }
// Set that this dynamic symbol needs a special value in the dynamic
// symbol table.
void
set_needs_dynsym_value()
{
gold_assert(this->object()->is_dynamic());
this->needs_dynsym_value_ = true;
}
// Return true if the final value of this symbol is known at link
// time.
bool
final_value_is_known() const;
// Return true if SHNDX represents a common symbol. This depends on
// the target.
static bool
is_common_shndx(unsigned int shndx);
// Return whether this is a defined symbol (not undefined or
// common).
bool
is_defined() const
{
bool is_ordinary;
if (this->source_ != FROM_OBJECT)
return this->source_ != IS_UNDEFINED;
unsigned int shndx = this->shndx(&is_ordinary);
return (is_ordinary
? shndx != elfcpp::SHN_UNDEF
: !Symbol::is_common_shndx(shndx));
}
// Return true if this symbol is from a dynamic object.
bool
is_from_dynobj() const
{
return this->source_ == FROM_OBJECT && this->object()->is_dynamic();
}
// Return whether this is a placeholder symbol from a plugin object.
bool
is_placeholder() const
{
return this->source_ == FROM_OBJECT && this->object()->pluginobj() != NULL;
}
// Return whether this is an undefined symbol.
bool
is_undefined() const
{
bool is_ordinary;
return ((this->source_ == FROM_OBJECT
&& this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF
&& is_ordinary)
|| this->source_ == IS_UNDEFINED);
}
// Return whether this is a weak undefined symbol.
bool
is_weak_undefined() const
{ return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; }
// Return whether this is an absolute symbol.
bool
is_absolute() const
{
bool is_ordinary;
return ((this->source_ == FROM_OBJECT
&& this->shndx(&is_ordinary) == elfcpp::SHN_ABS
&& !is_ordinary)
|| this->source_ == IS_CONSTANT);
}
// Return whether this is a common symbol.
bool
is_common() const
{
if (this->source_ != FROM_OBJECT)
return false;
if (this->type_ == elfcpp::STT_COMMON)
return true;
bool is_ordinary;
unsigned int shndx = this->shndx(&is_ordinary);
return !is_ordinary && Symbol::is_common_shndx(shndx);
}
// Return whether this symbol can be seen outside this object.
bool
is_externally_visible() const
{
return ((this->visibility_ == elfcpp::STV_DEFAULT
|| this->visibility_ == elfcpp::STV_PROTECTED)
&& !this->is_forced_local_);
}
// Return true if this symbol can be preempted by a definition in
// another link unit.
bool
is_preemptible() const
{
// It doesn't make sense to ask whether a symbol defined in
// another object is preemptible.
gold_assert(!this->is_from_dynobj());
// It doesn't make sense to ask whether an undefined symbol
// is preemptible.
gold_assert(!this->is_undefined());
// If a symbol does not have default visibility, it can not be
// seen outside this link unit and therefore is not preemptible.
if (this->visibility_ != elfcpp::STV_DEFAULT)
return false;
// If this symbol has been forced to be a local symbol by a
// version script, then it is not visible outside this link unit
// and is not preemptible.
if (this->is_forced_local_)
return false;
// If we are not producing a shared library, then nothing is
// preemptible.
if (!parameters->options().shared())
return false;
// If the user used -Bsymbolic, then nothing is preemptible.
if (parameters->options().Bsymbolic())
return false;
// If the user used -Bsymbolic-functions, then functions are not
// preemptible. We explicitly check for not being STT_OBJECT,
// rather than for being STT_FUNC, because that is what the GNU
// linker does.
if (this->type() != elfcpp::STT_OBJECT
&& parameters->options().Bsymbolic_functions())
return false;
// Otherwise the symbol is preemptible.
return true;
}
// Return true if this symbol is a function that needs a PLT entry.
bool
needs_plt_entry() const
{
// An undefined symbol from an executable does not need a PLT entry.
if (this->is_undefined() && !parameters->options().shared())
return false;
// An STT_GNU_IFUNC symbol always needs a PLT entry, even when
// doing a static link.
if (this->type() == elfcpp::STT_GNU_IFUNC)
return true;
// We only need a PLT entry for a function.
if (!this->is_func())
return false;
// If we're doing a static link or a -pie link, we don't create
// PLT entries.
if (parameters->doing_static_link()
|| parameters->options().pie())
return false;
// We need a PLT entry if the function is defined in a dynamic
// object, or is undefined when building a shared object, or if it
// is subject to pre-emption.
return (this->is_from_dynobj()
|| this->is_undefined()
|| this->is_preemptible());
}
// When determining whether a reference to a symbol needs a dynamic
// relocation, we need to know several things about the reference.
// These flags may be or'ed together. 0 means that the symbol
// isn't referenced at all.
enum Reference_flags
{
// A reference to the symbol's absolute address. This includes
// references that cause an absolute address to be stored in the GOT.
ABSOLUTE_REF = 1,
// A reference that calculates the offset of the symbol from some
// anchor point, such as the PC or GOT.
RELATIVE_REF = 2,
// A TLS-related reference.
TLS_REF = 4,
// A reference that can always be treated as a function call.
FUNCTION_CALL = 8
};
// Given a direct absolute or pc-relative static relocation against
// the global symbol, this function returns whether a dynamic relocation
// is needed.
bool
needs_dynamic_reloc(int flags) const
{
// No dynamic relocations in a static link!
if (parameters->doing_static_link())
return false;
// A reference to an undefined symbol from an executable should be
// statically resolved to 0, and does not need a dynamic relocation.
// This matches gnu ld behavior.
if (this->is_undefined() && !parameters->options().shared())
return false;
// A reference to an absolute symbol does not need a dynamic relocation.
if (this->is_absolute())
return false;
// An absolute reference within a position-independent output file
// will need a dynamic relocation.
if ((flags & ABSOLUTE_REF)
&& parameters->options().output_is_position_independent())
return true;
// A function call that can branch to a local PLT entry does not need
// a dynamic relocation.
if ((flags & FUNCTION_CALL) && this->has_plt_offset())
return false;
// A reference to any PLT entry in a non-position-independent executable
// does not need a dynamic relocation.
if (!parameters->options().output_is_position_independent()
&& this->has_plt_offset())
return false;
// A reference to a symbol defined in a dynamic object or to a
// symbol that is preemptible will need a dynamic relocation.
if (this->is_from_dynobj()
|| this->is_undefined()
|| this->is_preemptible())
return true;
// For all other cases, return FALSE.
return false;
}
// Whether we should use the PLT offset associated with a symbol for
// a relocation. FLAGS is a set of Reference_flags.
bool
use_plt_offset(int flags) const
{
// If the symbol doesn't have a PLT offset, then naturally we
// don't want to use it.
if (!this->has_plt_offset())
return false;
// For a STT_GNU_IFUNC symbol we always have to use the PLT entry.
if (this->type() == elfcpp::STT_GNU_IFUNC)
return true;
// If we are going to generate a dynamic relocation, then we will
// wind up using that, so no need to use the PLT entry.
if (this->needs_dynamic_reloc(flags))
return false;
// If the symbol is from a dynamic object, we need to use the PLT
// entry.
if (this->is_from_dynobj())
return true;
// If we are generating a shared object, and this symbol is
// undefined or preemptible, we need to use the PLT entry.
if (parameters->options().shared()
&& (this->is_undefined() || this->is_preemptible()))
return true;
// If this is a call to a weak undefined symbol, we need to use
// the PLT entry; the symbol may be defined by a library loaded
// at runtime.
if ((flags & FUNCTION_CALL) && this->is_weak_undefined())
return true;
// Otherwise we can use the regular definition.
return false;
}
// Given a direct absolute static relocation against
// the global symbol, where a dynamic relocation is needed, this
// function returns whether a relative dynamic relocation can be used.
// The caller must determine separately whether the static relocation
// is compatible with a relative relocation.
bool
can_use_relative_reloc(bool is_function_call) const
{
// A function call that can branch to a local PLT entry can
// use a RELATIVE relocation.
if (is_function_call && this->has_plt_offset())
return true;
// A reference to a symbol defined in a dynamic object or to a
// symbol that is preemptible can not use a RELATIVE relocation.
if (this->is_from_dynobj()
|| this->is_undefined()
|| this->is_preemptible())
return false;
// For all other cases, return TRUE.
return true;
}
// Return the output section where this symbol is defined. Return
// NULL if the symbol has an absolute value.
Output_section*
output_section() const;
// Set the symbol's output section. This is used for symbols
// defined in scripts. This should only be called after the symbol
// table has been finalized.
void
set_output_section(Output_section*);
// Return whether there should be a warning for references to this
// symbol.
bool
has_warning() const
{ return this->has_warning_; }
// Mark this symbol as having a warning.
void
set_has_warning()
{ this->has_warning_ = true; }
// Return whether this symbol is defined by a COPY reloc from a
// dynamic object.
bool
is_copied_from_dynobj() const
{ return this->is_copied_from_dynobj_; }
// Mark this symbol as defined by a COPY reloc.
void
set_is_copied_from_dynobj()
{ this->is_copied_from_dynobj_ = true; }
// Return whether this symbol is forced to visibility STB_LOCAL
// by a "local:" entry in a version script.
bool
is_forced_local() const
{ return this->is_forced_local_; }
// Mark this symbol as forced to STB_LOCAL visibility.
void
set_is_forced_local()
{ this->is_forced_local_ = true; }
// Return true if this may need a COPY relocation.
// References from an executable object to non-function symbols
// defined in a dynamic object may need a COPY relocation.
bool
may_need_copy_reloc() const
{
return (!parameters->options().output_is_position_independent()
&& parameters->options().copyreloc()
&& this->is_from_dynobj()
&& !this->is_func());
}
// Return true if this symbol was predefined by the linker.
bool
is_predefined() const
{ return this->is_predefined_; }
protected:
// Instances of this class should always be created at a specific
// size.
Symbol()
{ memset(this, 0, sizeof *this); }
// Initialize the general fields.
void
init_fields(const char* name, const char* version,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis);
// Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
// section index, IS_ORDINARY is whether it is a normal section
// index rather than a special code.
template<int size, bool big_endian>
void
init_base_object(const char* name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
bool is_ordinary);
// Initialize fields for an Output_data.
void
init_base_output_data(const char* name, const char* version, Output_data*,
elfcpp::STT, elfcpp::STB, elfcpp::STV,
unsigned char nonvis, bool offset_is_from_end,
bool is_predefined);
// Initialize fields for an Output_segment.
void
init_base_output_segment(const char* name, const char* version,
Output_segment* os, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis,
Segment_offset_base offset_base,
bool is_predefined);
// Initialize fields for a constant.
void
init_base_constant(const char* name, const char* version, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, bool is_predefined);
// Initialize fields for an undefined symbol.
void
init_base_undefined(const char* name, const char* version, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis);
// Override existing symbol.
template<int size, bool big_endian>
void
override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
bool is_ordinary, Object* object, const char* version);
// Override existing symbol with a special symbol.
void
override_base_with_special(const Symbol* from);
// Override symbol version.
void
override_version(const char* version);
// Allocate a common symbol by giving it a location in the output
// file.
void
allocate_base_common(Output_data*);
private:
Symbol(const Symbol&);
Symbol& operator=(const Symbol&);
// Symbol name (expected to point into a Stringpool).
const char* name_;
// Symbol version (expected to point into a Stringpool). This may
// be NULL.
const char* version_;
union
{
// This struct is used if SOURCE_ == FROM_OBJECT.
struct
{
// Object in which symbol is defined, or in which it was first
// seen.
Object* object;
// Section number in object_ in which symbol is defined.
unsigned int shndx;
} from_object;
// This struct is used if SOURCE_ == IN_OUTPUT_DATA.
struct
{
// Output_data in which symbol is defined. Before
// Layout::finalize the symbol's value is an offset within the
// Output_data.
Output_data* output_data;
// True if the offset is from the end, false if the offset is
// from the beginning.
bool offset_is_from_end;
} in_output_data;
// This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
struct
{
// Output_segment in which the symbol is defined. Before
// Layout::finalize the symbol's value is an offset.
Output_segment* output_segment;
// The base to use for the offset before Layout::finalize.
Segment_offset_base offset_base;
} in_output_segment;
} u_;
// The index of this symbol in the output file. If the symbol is
// not going into the output file, this value is -1U. This field
// starts as always holding zero. It is set to a non-zero value by
// Symbol_table::finalize.
unsigned int symtab_index_;
// The index of this symbol in the dynamic symbol table. If the
// symbol is not going into the dynamic symbol table, this value is
// -1U. This field starts as always holding zero. It is set to a
// non-zero value during Layout::finalize.
unsigned int dynsym_index_;
// The GOT section entries for this symbol. 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_offset_list got_offsets_;
// If this symbol has an entry in the PLT section, then this is the
// offset from the start of the PLT section. This is -1U if there
// is no PLT entry.
unsigned int plt_offset_;
// Symbol type (bits 0 to 3).
elfcpp::STT type_ : 4;
// Symbol binding (bits 4 to 7).
elfcpp::STB binding_ : 4;
// Symbol visibility (bits 8 to 9).
elfcpp::STV visibility_ : 2;
// Rest of symbol st_other field (bits 10 to 15).
unsigned int nonvis_ : 6;
// The type of symbol (bits 16 to 18).
Source source_ : 3;
// True if this is the default version of the symbol (bit 19).
bool is_def_ : 1;
// True if this symbol really forwards to another symbol. This is
// used when we discover after the fact that two different entries
// in the hash table really refer to the same symbol. This will
// never be set for a symbol found in the hash table, but may be set
// for a symbol found in the list of symbols attached to an Object.
// It forwards to the symbol found in the forwarders_ map of
// Symbol_table (bit 20).
bool is_forwarder_ : 1;
// True if the symbol has an alias in the weak_aliases table in
// Symbol_table (bit 21).
bool has_alias_ : 1;
// True if this symbol needs to be in the dynamic symbol table (bit
// 22).
bool needs_dynsym_entry_ : 1;
// True if we've seen this symbol in a regular object (bit 23).
bool in_reg_ : 1;
// True if we've seen this symbol in a dynamic object (bit 24).
bool in_dyn_ : 1;
// True if this is a dynamic symbol which needs a special value in
// the dynamic symbol table (bit 25).
bool needs_dynsym_value_ : 1;
// True if there is a warning for this symbol (bit 26).
bool has_warning_ : 1;
// True if we are using a COPY reloc for this symbol, so that the
// real definition lives in a dynamic object (bit 27).
bool is_copied_from_dynobj_ : 1;
// True if this symbol was forced to local visibility by a version
// script (bit 28).
bool is_forced_local_ : 1;
// True if the field u_.from_object.shndx is an ordinary section
// index, not one of the special codes from SHN_LORESERVE to
// SHN_HIRESERVE (bit 29).
bool is_ordinary_shndx_ : 1;
// True if we've seen this symbol in a "real" ELF object (bit 30).
// If the symbol has been seen in a relocatable, non-IR, object file,
// it's known to be referenced from outside the IR. A reference from
// a dynamic object doesn't count as a "real" ELF, and we'll simply
// mark the symbol as "visible" from outside the IR. The compiler
// can use this distinction to guide its handling of COMDAT symbols.
bool in_real_elf_ : 1;
// True if this symbol is defined in a section which was discarded
// (bit 31).
bool is_defined_in_discarded_section_ : 1;
// True if UNDEF_BINDING_WEAK_ has been set (bit 32).
bool undef_binding_set_ : 1;
// True if this symbol was a weak undef resolved by a dynamic def
// (bit 33).
bool undef_binding_weak_ : 1;
// True if this symbol is a predefined linker symbol (bit 34).
bool is_predefined_ : 1;
};
// The parts of a symbol which are size specific. Using a template
// derived class like this helps us use less space on a 32-bit system.
template<int size>
class Sized_symbol : public Symbol
{
public:
typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type;
typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type;
Sized_symbol()
{ }
// Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the
// section index, IS_ORDINARY is whether it is a normal section
// index rather than a special code.
template<bool big_endian>
void
init_object(const char* name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
bool is_ordinary);
// Initialize fields for an Output_data.
void
init_output_data(const char* name, const char* version, Output_data*,
Value_type value, Size_type symsize, elfcpp::STT,
elfcpp::STB, elfcpp::STV, unsigned char nonvis,
bool offset_is_from_end, bool is_predefined);
// Initialize fields for an Output_segment.
void
init_output_segment(const char* name, const char* version, Output_segment*,
Value_type value, Size_type symsize, elfcpp::STT,
elfcpp::STB, elfcpp::STV, unsigned char nonvis,
Segment_offset_base offset_base, bool is_predefined);
// Initialize fields for a constant.
void
init_constant(const char* name, const char* version, Value_type value,
Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV,
unsigned char nonvis, bool is_predefined);
// Initialize fields for an undefined symbol.
void
init_undefined(const char* name, const char* version, elfcpp::STT,
elfcpp::STB, elfcpp::STV, unsigned char nonvis);
// Override existing symbol.
template<bool big_endian>
void
override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx,
bool is_ordinary, Object* object, const char* version);
// Override existing symbol with a special symbol.
void
override_with_special(const Sized_symbol<size>*);
// Return the symbol's value.
Value_type
value() const
{ return this->value_; }
// Return the symbol's size (we can't call this 'size' because that
// is a template parameter).
Size_type
symsize() const
{ return this->symsize_; }
// Set the symbol size. This is used when resolving common symbols.
void
set_symsize(Size_type symsize)
{ this->symsize_ = symsize; }
// Set the symbol value. This is called when we store the final
// values of the symbols into the symbol table.
void
set_value(Value_type value)
{ this->value_ = value; }
// Allocate a common symbol by giving it a location in the output
// file.
void
allocate_common(Output_data*, Value_type value);
private:
Sized_symbol(const Sized_symbol&);
Sized_symbol& operator=(const Sized_symbol&);
// Symbol value. Before Layout::finalize this is the offset in the
// input section. This is set to the final value during
// Layout::finalize.
Value_type value_;
// Symbol size.
Size_type symsize_;
};
// A struct describing a symbol defined by the linker, where the value
// of the symbol is defined based on an output section. This is used
// for symbols defined by the linker, like "_init_array_start".
struct Define_symbol_in_section
{
// The symbol name.
const char* name;
// The name of the output section with which this symbol should be
// associated. If there is no output section with that name, the
// symbol will be defined as zero.
const char* output_section;
// The offset of the symbol within the output section. This is an
// offset from the start of the output section, unless start_at_end
// is true, in which case this is an offset from the end of the
// output section.
uint64_t value;
// The size of the symbol.
uint64_t size;
// The symbol type.
elfcpp::STT type;
// The symbol binding.
elfcpp::STB binding;
// The symbol visibility.
elfcpp::STV visibility;
// The rest of the st_other field.
unsigned char nonvis;
// If true, the value field is an offset from the end of the output
// section.
bool offset_is_from_end;
// If true, this symbol is defined only if we see a reference to it.
bool only_if_ref;
};
// A struct describing a symbol defined by the linker, where the value
// of the symbol is defined based on a segment. This is used for
// symbols defined by the linker, like "_end". We describe the
// segment with which the symbol should be associated by its
// characteristics. If no segment meets these characteristics, the
// symbol will be defined as zero. If there is more than one segment
// which meets these characteristics, we will use the first one.
struct Define_symbol_in_segment
{
// The symbol name.
const char* name;
// The segment type where the symbol should be defined, typically
// PT_LOAD.
elfcpp::PT segment_type;
// Bitmask of segment flags which must be set.
elfcpp::PF segment_flags_set;
// Bitmask of segment flags which must be clear.
elfcpp::PF segment_flags_clear;
// The offset of the symbol within the segment. The offset is
// calculated from the position set by offset_base.
uint64_t value;
// The size of the symbol.
uint64_t size;
// The symbol type.
elfcpp::STT type;
// The symbol binding.
elfcpp::STB binding;
// The symbol visibility.
elfcpp::STV visibility;
// The rest of the st_other field.
unsigned char nonvis;
// The base from which we compute the offset.
Symbol::Segment_offset_base offset_base;
// If true, this symbol is defined only if we see a reference to it.
bool only_if_ref;
};
// Specify an object/section/offset location. Used by ODR code.
struct Symbol_location
{
// Object where the symbol is defined.
Object* object;
// Section-in-object where the symbol is defined.
unsigned int shndx;
// For relocatable objects, offset-in-section where the symbol is defined.
// For dynamic objects, address where the symbol is defined.
off_t offset;
bool operator==(const Symbol_location& that) const
{
return (this->object == that.object
&& this->shndx == that.shndx
&& this->offset == that.offset);
}
};
// This class manages warnings. Warnings are a GNU extension. When
// we see a section named .gnu.warning.SYM in an object file, and if
// we wind using the definition of SYM from that object file, then we
// will issue a warning for any relocation against SYM from a
// different object file. The text of the warning is the contents of
// the section. This is not precisely the definition used by the old
// GNU linker; the old GNU linker treated an occurrence of
// .gnu.warning.SYM as defining a warning symbol. A warning symbol
// would trigger a warning on any reference. However, it was
// inconsistent in that a warning in a dynamic object only triggered
// if there was no definition in a regular object. This linker is
// different in that we only issue a warning if we use the symbol
// definition from the same object file as the warning section.
class Warnings
{
public:
Warnings()
: warnings_()
{ }
// Add a warning for symbol NAME in object OBJ. WARNING is the text
// of the warning.
void
add_warning(Symbol_table* symtab, const char* name, Object* obj,
const std::string& warning);
// For each symbol for which we should give a warning, make a note
// on the symbol.
void
note_warnings(Symbol_table* symtab);
// Issue a warning for a reference to SYM at RELINFO's location.
template<int size, bool big_endian>
void
issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*,
size_t relnum, off_t reloffset) const;
private:
Warnings(const Warnings&);
Warnings& operator=(const Warnings&);
// What we need to know to get the warning text.
struct Warning_location
{
// The object the warning is in.
Object* object;
// The warning text.
std::string text;
Warning_location()
: object(NULL), text()
{ }
void
set(Object* o, const std::string& t)
{
this->object = o;
this->text = t;
}
};
// A mapping from warning symbol names (canonicalized in
// Symbol_table's namepool_ field) to warning information.
typedef Unordered_map<const char*, Warning_location> Warning_table;
Warning_table warnings_;
};
// The main linker symbol table.
class Symbol_table
{
public:
// The different places where a symbol definition can come from.
enum Defined
{
// Defined in an object file--the normal case.
OBJECT,
// Defined for a COPY reloc.
COPY,
// Defined on the command line using --defsym.
DEFSYM,
// Defined (so to speak) on the command line using -u.
UNDEFINED,
// Defined in a linker script.
SCRIPT,
// Predefined by the linker.
PREDEFINED,
// Defined by the linker during an incremental base link, but not
// a predefined symbol (e.g., common, defined in script).
INCREMENTAL_BASE,
};
// The order in which we sort common symbols.
enum Sort_commons_order
{
SORT_COMMONS_BY_SIZE_DESCENDING,
SORT_COMMONS_BY_ALIGNMENT_DESCENDING,
SORT_COMMONS_BY_ALIGNMENT_ASCENDING
};
// COUNT is an estimate of how many symbols will be inserted in the
// symbol table. It's ok to put 0 if you don't know; a correct
// guess will just save some CPU by reducing hashtable resizes.
Symbol_table(unsigned int count, const Version_script_info& version_script);
~Symbol_table();
void
set_icf(Icf* icf)
{ this->icf_ = icf;}
Icf*
icf() const
{ return this->icf_; }
// Returns true if ICF determined that this is a duplicate section.
bool
is_section_folded(Object* obj, unsigned int shndx) const;
void
set_gc(Garbage_collection* gc)
{ this->gc_ = gc; }
Garbage_collection*
gc() const
{ return this->gc_; }
// During garbage collection, this keeps undefined symbols.
void
gc_mark_undef_symbols(Layout*);
// This tells garbage collection that this symbol is referenced.
void
gc_mark_symbol(Symbol* sym);
// During garbage collection, this keeps sections that correspond to
// symbols seen in dynamic objects.
inline void
gc_mark_dyn_syms(Symbol* sym);
// Add COUNT external symbols from the relocatable object RELOBJ to
// the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the
// offset in the symbol table of the first symbol, SYM_NAMES is
// their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets
// SYMPOINTERS to point to the symbols in the symbol table. It sets
// *DEFINED to the number of defined symbols.
template<int size, bool big_endian>
void
add_from_relobj(Sized_relobj_file<size, big_endian>* relobj,
const unsigned char* syms, size_t count,
size_t symndx_offset, const char* sym_names,
size_t sym_name_size,
typename Sized_relobj_file<size, big_endian>::Symbols*,
size_t* defined);
// Add one external symbol from the plugin object OBJ to the symbol table.
// Returns a pointer to the resolved symbol in the symbol table.
template<int size, bool big_endian>
Symbol*
add_from_pluginobj(Sized_pluginobj<size, big_endian>* obj,
const char* name, const char* ver,
elfcpp::Sym<size, big_endian>* sym);
// Add COUNT dynamic symbols from the dynamic object DYNOBJ to the
// symbol table. SYMS is the symbols. SYM_NAMES is their names.
// SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are
// symbol version data.
template<int size, bool big_endian>
void
add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj,
const unsigned char* syms, size_t count,
const char* sym_names, size_t sym_name_size,
const unsigned char* versym, size_t versym_size,
const std::vector<const char*>*,
typename Sized_relobj_file<size, big_endian>::Symbols*,
size_t* defined);
// Add one external symbol from the incremental object OBJ to the symbol
// table. Returns a pointer to the resolved symbol in the symbol table.
template<int size, bool big_endian>
Sized_symbol<size>*
add_from_incrobj(Object* obj, const char* name,
const char* ver, elfcpp::Sym<size, big_endian>* sym);
// Define a special symbol based on an Output_data. It is a
// multiple definition error if this symbol is already defined.
Symbol*
define_in_output_data(const char* name, const char* version, Defined,
Output_data*, uint64_t value, uint64_t symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool offset_is_from_end, bool only_if_ref);
// Define a special symbol based on an Output_segment. It is a
// multiple definition error if this symbol is already defined.
Symbol*
define_in_output_segment(const char* name, const char* version, Defined,
Output_segment*, uint64_t value, uint64_t symsize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
Symbol::Segment_offset_base, bool only_if_ref);
// Define a special symbol with a constant value. It is a multiple
// definition error if this symbol is already defined.
Symbol*
define_as_constant(const char* name, const char* version, Defined,
uint64_t value, uint64_t symsize, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis, bool only_if_ref,
bool force_override);
// Define a set of symbols in output sections. If ONLY_IF_REF is
// true, only define them if they are referenced.
void
define_symbols(const Layout*, int count, const Define_symbol_in_section*,
bool only_if_ref);
// Define a set of symbols in output segments. If ONLY_IF_REF is
// true, only defined them if they are referenced.
void
define_symbols(const Layout*, int count, const Define_symbol_in_segment*,
bool only_if_ref);
// Define SYM using a COPY reloc. POSD is the Output_data where the
// symbol should be defined--typically a .dyn.bss section. VALUE is
// the offset within POSD.
template<int size>
void
define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd,
typename elfcpp::Elf_types<size>::Elf_Addr);
// Look up a symbol.
Symbol*
lookup(const char*, const char* version = NULL) const;
// Return the real symbol associated with the forwarder symbol FROM.
Symbol*
resolve_forwards(const Symbol* from) const;
// Return the sized version of a symbol in this table.
template<int size>
Sized_symbol<size>*
get_sized_symbol(Symbol*) const;
template<int size>
const Sized_symbol<size>*
get_sized_symbol(const Symbol*) const;
// Return the count of undefined symbols seen.
size_t
saw_undefined() const
{ return this->saw_undefined_; }
// Allocate the common symbols
void
allocate_commons(Layout*, Mapfile*);
// Add a warning for symbol NAME in object OBJ. WARNING is the text
// of the warning.
void
add_warning(const char* name, Object* obj, const std::string& warning)
{ this->warnings_.add_warning(this, name, obj, warning); }
// Canonicalize a symbol name for use in the hash table.
const char*
canonicalize_name(const char* name)
{ return this->namepool_.add(name, true, NULL); }
// Possibly issue a warning for a reference to SYM at LOCATION which
// is in OBJ.
template<int size, bool big_endian>
void
issue_warning(const Symbol* sym,
const Relocate_info<size, big_endian>* relinfo,
size_t relnum, off_t reloffset) const
{ this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); }
// Check candidate_odr_violations_ to find symbols with the same name
// but apparently different definitions (different source-file/line-no).
void
detect_odr_violations(const Task*, const char* output_file_name) const;
// Add any undefined symbols named on the command line to the symbol
// table.
void
add_undefined_symbols_from_command_line(Layout*);
// SYM is defined using a COPY reloc. Return the dynamic object
// where the original definition was found.
Dynobj*
get_copy_source(const Symbol* sym) const;
// Set the dynamic symbol indexes. INDEX is the index of the first
// global dynamic symbol. Pointers to the symbols are stored into
// the vector. The names are stored into the Stringpool. This
// returns an updated dynamic symbol index.
unsigned int
set_dynsym_indexes(unsigned int index, std::vector<Symbol*>*,
Stringpool*, Versions*);
// Finalize the symbol table after we have set the final addresses
// of all the input sections. This sets the final symbol indexes,
// values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the
// index of the first global symbol. OFF is the file offset of the
// global symbol table, DYNOFF is the offset of the globals in the
// dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first
// global dynamic symbol, and DYNCOUNT is the number of global
// dynamic symbols. This records the parameters, and returns the
// new file offset. It updates *PLOCAL_SYMCOUNT if it created any
// local symbols.
off_t
finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
Stringpool* pool, unsigned int* plocal_symcount);
// Set the final file offset of the symbol table.
void
set_file_offset(off_t off)
{ this->offset_ = off; }
// Status code of Symbol_table::compute_final_value.
enum Compute_final_value_status
{
// No error.
CFVS_OK,
// Unsupported symbol section.
CFVS_UNSUPPORTED_SYMBOL_SECTION,
// No output section.
CFVS_NO_OUTPUT_SECTION
};
// Compute the final value of SYM and store status in location PSTATUS.
// During relaxation, this may be called multiple times for a symbol to
// compute its would-be final value in each relaxation pass.
template<int size>
typename Sized_symbol<size>::Value_type
compute_final_value(const Sized_symbol<size>* sym,
Compute_final_value_status* pstatus) const;
// Return the index of the first global symbol.
unsigned int
first_global_index() const
{ return this->first_global_index_; }
// Return the total number of symbols in the symbol table.
unsigned int
output_count() const
{ return this->output_count_; }
// Write out the global symbols.
void
write_globals(const Stringpool*, const Stringpool*,
Output_symtab_xindex*, Output_symtab_xindex*,
Output_file*) const;
// Write out a section symbol. Return the updated offset.
void
write_section_symbol(const Output_section*, Output_symtab_xindex*,
Output_file*, off_t) const;
// Loop over all symbols, applying the function F to each.
template<int size, typename F>
void
for_all_symbols(F f) const
{
for (Symbol_table_type::const_iterator p = this->table_.begin();
p != this->table_.end();
++p)
{
Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second);
f(sym);
}
}
// Dump statistical information to stderr.
void
print_stats() const;
// Return the version script information.
const Version_script_info&
version_script() const
{ return version_script_; }
private:
Symbol_table(const Symbol_table&);
Symbol_table& operator=(const Symbol_table&);
// The type of the list of common symbols.
typedef std::vector<Symbol*> Commons_type;
// The type of the symbol hash table.
typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
// The hash function. The key values are Stringpool keys.
struct Symbol_table_hash
{
inline size_t
operator()(const Symbol_table_key& key) const
{
return key.first ^ key.second;
}
};
struct Symbol_table_eq
{
bool
operator()(const Symbol_table_key&, const Symbol_table_key&) const;
};
typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
Symbol_table_eq> Symbol_table_type;
// A map from symbol name (as a pointer into the namepool) to all
// the locations the symbols is (weakly) defined (and certain other
// conditions are met). This map will be used later to detect
// possible One Definition Rule (ODR) violations.
struct Symbol_location_hash
{
size_t operator()(const Symbol_location& loc) const
{ return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
};
typedef Unordered_map<const char*,
Unordered_set<Symbol_location, Symbol_location_hash> >
Odr_map;
// Make FROM a forwarder symbol to TO.
void
make_forwarder(Symbol* from, Symbol* to);
// Add a symbol.
template<int size, bool big_endian>
Sized_symbol<size>*
add_from_object(Object*, const char* name, Stringpool::Key name_key,
const char* version, Stringpool::Key version_key,
bool def, const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx, bool is_ordinary,
unsigned int orig_st_shndx);
// Define a default symbol.
template<int size, bool big_endian>
void
define_default_version(Sized_symbol<size>*, bool,
Symbol_table_type::iterator);
// Resolve symbols.
template<int size, bool big_endian>
void
resolve(Sized_symbol<size>* to,
const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx, bool is_ordinary,
unsigned int orig_st_shndx,
Object*, const char* version);
template<int size, bool big_endian>
void
resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
// Record that a symbol is forced to be local by a version script or
// by visibility.
void
force_local(Symbol*);
// Adjust NAME and *NAME_KEY for wrapping.
const char*
wrap_symbol(const char* name, Stringpool::Key* name_key);
// Whether we should override a symbol, based on flags in
// resolve.cc.
static bool
should_override(const Symbol*, unsigned int, elfcpp::STT, Defined,
Object*, bool*, bool*);
// Report a problem in symbol resolution.
static void
report_resolve_problem(bool is_error, const char* msg, const Symbol* to,
Defined, Object* object);
// Override a symbol.
template<int size, bool big_endian>
void
override(Sized_symbol<size>* tosym,
const elfcpp::Sym<size, big_endian>& fromsym,
unsigned int st_shndx, bool is_ordinary,
Object* object, const char* version);
// Whether we should override a symbol with a special symbol which
// is automatically defined by the linker.
static bool
should_override_with_special(const Symbol*, elfcpp::STT, Defined);
// Override a symbol with a special symbol.
template<int size>
void
override_with_special(Sized_symbol<size>* tosym,
const Sized_symbol<size>* fromsym);
// Record all weak alias sets for a dynamic object.
template<int size>
void
record_weak_aliases(std::vector<Sized_symbol<size>*>*);
// Define a special symbol.
template<int size, bool big_endian>
Sized_symbol<size>*
define_special_symbol(const char** pname, const char** pversion,
bool only_if_ref, Sized_symbol<size>** poldsym,
bool* resolve_oldsym);
// Define a symbol in an Output_data, sized version.
template<int size>
Sized_symbol<size>*
do_define_in_output_data(const char* name, const char* version, Defined,
Output_data*,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool offset_is_from_end, bool only_if_ref);
// Define a symbol in an Output_segment, sized version.
template<int size>
Sized_symbol<size>*
do_define_in_output_segment(
const char* name, const char* version, Defined, Output_segment* os,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
Symbol::Segment_offset_base offset_base, bool only_if_ref);
// Define a symbol as a constant, sized version.
template<int size>
Sized_symbol<size>*
do_define_as_constant(
const char* name, const char* version, Defined,
typename elfcpp::Elf_types<size>::Elf_Addr value,
typename elfcpp::Elf_types<size>::Elf_WXword ssize,
elfcpp::STT type, elfcpp::STB binding,
elfcpp::STV visibility, unsigned char nonvis,
bool only_if_ref, bool force_override);
// Add any undefined symbols named on the command line to the symbol
// table, sized version.
template<int size>
void
do_add_undefined_symbols_from_command_line(Layout*);
// Add one undefined symbol.
template<int size>
void
add_undefined_symbol_from_command_line(const char* name);
// Types of common symbols.
enum Commons_section_type
{
COMMONS_NORMAL,
COMMONS_TLS,
COMMONS_SMALL,
COMMONS_LARGE
};
// Allocate the common symbols, sized version.
template<int size>
void
do_allocate_commons(Layout*, Mapfile*, Sort_commons_order);
// Allocate the common symbols from one list.
template<int size>
void
do_allocate_commons_list(Layout*, Commons_section_type, Commons_type*,
Mapfile*, Sort_commons_order);
// Returns all of the lines attached to LOC, not just the one the
// instruction actually came from. This helps the ODR checker avoid
// false positives.
static std::vector<std::string>
linenos_from_loc(const Task* task, const Symbol_location& loc);
// Implement detect_odr_violations.
template<int size, bool big_endian>
void
sized_detect_odr_violations() const;
// Finalize symbols specialized for size.
template<int size>
off_t
sized_finalize(off_t, Stringpool*, unsigned int*);
// Finalize a symbol. Return whether it should be added to the
// symbol table.
template<int size>
bool
sized_finalize_symbol(Symbol*);
// Add a symbol the final symtab by setting its index.
template<int size>
void
add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff);
// Write globals specialized for size and endianness.
template<int size, bool big_endian>
void
sized_write_globals(const Stringpool*, const Stringpool*,
Output_symtab_xindex*, Output_symtab_xindex*,
Output_file*) const;
// Write out a symbol to P.
template<int size, bool big_endian>
void
sized_write_symbol(Sized_symbol<size>*,
typename elfcpp::Elf_types<size>::Elf_Addr value,
unsigned int shndx, elfcpp::STB,
const Stringpool*, unsigned char* p) const;
// Possibly warn about an undefined symbol from a dynamic object.
void
warn_about_undefined_dynobj_symbol(Symbol*) const;
// Write out a section symbol, specialized for size and endianness.
template<int size, bool big_endian>
void
sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
Output_file*, off_t) const;
// The type of the list of symbols which have been forced local.
typedef std::vector<Symbol*> Forced_locals;
// A map from symbols with COPY relocs to the dynamic objects where
// they are defined.
typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs;
// We increment this every time we see a new undefined symbol, for
// use in archive groups.
size_t saw_undefined_;
// The index of the first global symbol in the output file.
unsigned int first_global_index_;
// The file offset within the output symtab section where we should
// write the table.
off_t offset_;
// The number of global symbols we want to write out.
unsigned int output_count_;
// The file offset of the global dynamic symbols, or 0 if none.
off_t dynamic_offset_;
// The index of the first global dynamic symbol.
unsigned int first_dynamic_global_index_;
// The number of global dynamic symbols, or 0 if none.
unsigned int dynamic_count_;
// The symbol hash table.
Symbol_table_type table_;
// A pool of symbol names. This is used for all global symbols.
// Entries in the hash table point into this pool.
Stringpool namepool_;
// Forwarding symbols.
Unordered_map<const Symbol*, Symbol*> forwarders_;
// Weak aliases. A symbol in this list points to the next alias.
// The aliases point to each other in a circular list.
Unordered_map<Symbol*, Symbol*> weak_aliases_;
// We don't expect there to be very many common symbols, so we keep
// a list of them. When we find a common symbol we add it to this
// list. It is possible that by the time we process the list the
// symbol is no longer a common symbol. It may also have become a
// forwarder.
Commons_type commons_;
// This is like the commons_ field, except that it holds TLS common
// symbols.
Commons_type tls_commons_;
// This is for small common symbols.
Commons_type small_commons_;
// This is for large common symbols.
Commons_type large_commons_;
// A list of symbols which have been forced to be local. We don't
// expect there to be very many of them, so we keep a list of them
// rather than walking the whole table to find them.
Forced_locals forced_locals_;
// Manage symbol warnings.
Warnings warnings_;
// Manage potential One Definition Rule (ODR) violations.
Odr_map candidate_odr_violations_;
// When we emit a COPY reloc for a symbol, we define it in an
// Output_data. When it's time to emit version information for it,
// we need to know the dynamic object in which we found the original
// definition. This maps symbols with COPY relocs to the dynamic
// object where they were defined.
Copied_symbol_dynobjs copied_symbol_dynobjs_;
// Information parsed from the version script, if any.
const Version_script_info& version_script_;
Garbage_collection* gc_;
Icf* icf_;
};
// We inline get_sized_symbol for efficiency.
template<int size>
Sized_symbol<size>*
Symbol_table::get_sized_symbol(Symbol* sym) const
{
gold_assert(size == parameters->target().get_size());
return static_cast<Sized_symbol<size>*>(sym);
}
template<int size>
const Sized_symbol<size>*
Symbol_table::get_sized_symbol(const Symbol* sym) const
{
gold_assert(size == parameters->target().get_size());
return static_cast<const Sized_symbol<size>*>(sym);
}
} // End namespace gold.
#endif // !defined(GOLD_SYMTAB_H)
|