aboutsummaryrefslogtreecommitdiff
path: root/ld/ld.texinfo
blob: a884ffdf849780c3d196d3939ae55adfe0dd0e70 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
\input texinfo
@setfilename ld.info
@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
@c 2001, 2002 Free Software Foundation, Inc.
@syncodeindex ky cp
@include configdoc.texi
@c (configdoc.texi is generated by the Makefile)
@include ldver.texi

@c @smallbook

@macro gcctabopt{body}
@code{\body\}
@end macro

@c man begin NAME
@ifset man
@c Configure for the generation of man pages
@set UsesEnvVars
@set GENERIC
@set A29K
@set ARC
@set ARM
@set D10V
@set D30V
@set H8/300
@set H8/500
@set HPPA
@set I370
@set I80386
@set I860
@set I960
@set M32R
@set M68HC11
@set M680X0
@set MCORE
@set MIPS
@set MMIX
@set PDP11
@set PJ
@set SH
@set SPARC
@set C54X
@set V850
@set VAX
@end ifset
@c man end

@ifinfo
@format
START-INFO-DIR-ENTRY
* Ld: (ld).                       The GNU linker.
END-INFO-DIR-ENTRY
@end format
@end ifinfo

@ifinfo
This file documents the @sc{gnu} linker LD version @value{VERSION}.

Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
2001, 2002 Free Software Foundation, Inc.

@ignore

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
or any later version published by the Free Software Foundation;
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts.  A copy of the license is included in the
section entitled "GNU Free Documentation License".

Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
@end ifinfo
@iftex
@finalout
@setchapternewpage odd
@settitle Using LD, the GNU linker
@titlepage
@title Using ld
@subtitle The GNU linker
@sp 1
@subtitle @code{ld} version 2
@subtitle Version @value{VERSION}
@author Steve Chamberlain
@author Ian Lance Taylor
@page

@tex
{\parskip=0pt
\hfill Red Hat Inc\par
\hfill nickc\@credhat.com, doc\@redhat.com\par
\hfill {\it Using LD, the GNU linker}\par
\hfill Edited by Jeffrey Osier (jeffrey\@cygnus.com)\par
}
\global\parindent=0pt % Steve likes it this way.
@end tex

@vskip 0pt plus 1filll
@c man begin COPYRIGHT
Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
or any later version published by the Free Software Foundation;
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts.  A copy of the license is included in the
section entitled "GNU Free Documentation License".
@c man end

@end titlepage
@end iftex
@c FIXME: Talk about importance of *order* of args, cmds to linker!

@ifnottex
@node Top
@top Using ld
This file documents the @sc{gnu} linker ld version @value{VERSION}.

This document is distributed under the terms of the GNU Free
Documentation License.  A copy of the license is included in the
section entitled "GNU Free Documentation License".

@menu
* Overview::                    Overview
* Invocation::                  Invocation
* Scripts::                     Linker Scripts
@ifset GENERIC
* Machine Dependent::           Machine Dependent Features
@end ifset
@ifclear GENERIC
@ifset H8300
* H8/300::                      ld and the H8/300
@end ifset
@ifset Hitachi
* Hitachi::                     ld and other Hitachi micros
@end ifset
@ifset I960
* i960::                        ld and the Intel 960 family
@end ifset
@ifset TICOFF
* TI COFF::                     ld and the TI COFF
@end ifset
@end ifclear
@ifclear SingleFormat
* BFD::                         BFD
@end ifclear
@c Following blank line required for remaining bug in makeinfo conds/menus

* Reporting Bugs::              Reporting Bugs
* MRI::                         MRI Compatible Script Files
* GNU Free Documentation License::  GNU Free Documentation License
* Index::                       Index
@end menu
@end ifnottex

@node Overview
@chapter Overview

@cindex @sc{gnu} linker
@cindex what is this?

@ifset man
@c man begin SYNOPSIS
ld [@b{options}] @var{objfile} @dots{}
@c man end

@c man begin SEEALSO
ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and
the Info entries for @file{binutils} and
@file{ld}.
@c man end
@end ifset

@c man begin DESCRIPTION

@command{ld} combines a number of object and archive files, relocates
their data and ties up symbol references. Usually the last step in
compiling a program is to run @command{ld}.

@command{ld} accepts Linker Command Language files written in
a superset of AT&T's Link Editor Command Language syntax,
to provide explicit and total control over the linking process.

@ifset man
@c For the man only
This man page does not describe the command language; see the 
@command{ld} entry in @code{info}, or the manual
ld: the GNU linker, for full details on the command language and 
on other aspects of the GNU linker. 
@end ifset

@ifclear SingleFormat
This version of @command{ld} uses the general purpose BFD libraries
to operate on object files. This allows @command{ld} to read, combine, and
write object files in many different formats---for example, COFF or
@code{a.out}.  Different formats may be linked together to produce any
available kind of object file.  @xref{BFD}, for more information.
@end ifclear

Aside from its flexibility, the @sc{gnu} linker is more helpful than other
linkers in providing diagnostic information.  Many linkers abandon
execution immediately upon encountering an error; whenever possible,
@command{ld} continues executing, allowing you to identify other errors
(or, in some cases, to get an output file in spite of the error).

@c man end

@node Invocation
@chapter Invocation

@c man begin DESCRIPTION

The @sc{gnu} linker @command{ld} is meant to cover a broad range of situations,
and to be as compatible as possible with other linkers.  As a result,
you have many choices to control its behavior.

@c man end

@ifset UsesEnvVars
@menu
* Options::                     Command Line Options
* Environment::                 Environment Variables
@end menu

@node Options
@section Command Line Options
@end ifset

@cindex command line
@cindex options

@c man begin OPTIONS

The linker supports a plethora of command-line options, but in actual
practice few of them are used in any particular context.
@cindex standard Unix system
For instance, a frequent use of @command{ld} is to link standard Unix
object files on a standard, supported Unix system.  On such a system, to
link a file @code{hello.o}:

@smallexample
ld -o @var{output} /lib/crt0.o hello.o -lc
@end smallexample

This tells @command{ld} to produce a file called @var{output} as the
result of linking the file @code{/lib/crt0.o} with @code{hello.o} and
the library @code{libc.a}, which will come from the standard search
directories.  (See the discussion of the @samp{-l} option below.)

Some of the command-line options to @command{ld} may be specified at any
point in the command line.  However, options which refer to files, such
as @samp{-l} or @samp{-T}, cause the file to be read at the point at
which the option appears in the command line, relative to the object
files and other file options.  Repeating non-file options with a
different argument will either have no further effect, or override prior
occurrences (those further to the left on the command line) of that
option.  Options which may be meaningfully specified more than once are
noted in the descriptions below.

@cindex object files
Non-option arguments are object files or archives which are to be linked
together.  They may follow, precede, or be mixed in with command-line
options, except that an object file argument may not be placed between
an option and its argument.

Usually the linker is invoked with at least one object file, but you can
specify other forms of binary input files using @samp{-l}, @samp{-R},
and the script command language.  If @emph{no} binary input files at all
are specified, the linker does not produce any output, and issues the
message @samp{No input files}.

If the linker can not recognize the format of an object file, it will
assume that it is a linker script.  A script specified in this way
augments the main linker script used for the link (either the default
linker script or the one specified by using @samp{-T}).  This feature
permits the linker to link against a file which appears to be an object
or an archive, but actually merely defines some symbol values, or uses
@code{INPUT} or @code{GROUP} to load other objects.  Note that
specifying a script in this way merely augments the main linker script;
use the @samp{-T} option to replace the default linker script entirely.
@xref{Scripts}.

For options whose names are a single letter,
option arguments must either follow the option letter without intervening
whitespace, or be given as separate arguments immediately following the
option that requires them.

For options whose names are multiple letters, either one dash or two can
precede the option name; for example, @samp{-trace-symbol} and
@samp{--trace-symbol} are equivalent.  Note - there is one exception to
this rule.  Multiple letter options that start with a lower case 'o' can
only be preceeded by two dashes.  This is to reduce confusion with the
@samp{-o} option.  So for example @samp{-omagic} sets the output file
name to @samp{magic} whereas @samp{--omagic} sets the NMAGIC flag on the
output.

Arguments to multiple-letter options must either be separated from the
option name by an equals sign, or be given as separate arguments
immediately following the option that requires them.  For example,
@samp{--trace-symbol foo} and @samp{--trace-symbol=foo} are equivalent.
Unique abbreviations of the names of multiple-letter options are
accepted.

Note - if the linker is being invoked indirectly, via a compiler driver
(eg @samp{gcc}) then all the linker command line options should be
prefixed by @samp{-Wl,} (or whatever is appropriate for the particular
compiler driver) like this:

@smallexample
  gcc -Wl,--startgroup foo.o bar.o -Wl,--endgroup
@end smallexample

This is important, because otherwise the compiler driver program may
silently drop the linker options, resulting in a bad link.

Here is a table of the generic command line switches accepted by the GNU
linker:

@table @gcctabopt
@kindex -a@var{keyword}
@item -a@var{keyword}
This option is supported for HP/UX compatibility.  The @var{keyword}
argument must be one of the strings @samp{archive}, @samp{shared}, or
@samp{default}.  @samp{-aarchive} is functionally equivalent to
@samp{-Bstatic}, and the other two keywords are functionally equivalent
to @samp{-Bdynamic}.  This option may be used any number of times.

@ifset I960
@cindex architectures
@kindex -A@var{arch}
@item -A@var{architecture}
@kindex --architecture=@var{arch}
@itemx --architecture=@var{architecture}
In the current release of @command{ld}, this option is useful only for the
Intel 960 family of architectures.  In that @command{ld} configuration, the
@var{architecture} argument identifies the particular architecture in
the 960 family, enabling some safeguards and modifying the
archive-library search path.  @xref{i960,,@command{ld} and the Intel 960
family}, for details.

Future releases of @command{ld} may support similar functionality for
other architecture families.
@end ifset

@ifclear SingleFormat
@cindex binary input format
@kindex -b @var{format}
@kindex --format=@var{format}
@cindex input format
@cindex input format
@item -b @var{input-format}
@itemx --format=@var{input-format}
@command{ld} may be configured to support more than one kind of object
file.  If your @command{ld} is configured this way, you can use the
@samp{-b} option to specify the binary format for input object files
that follow this option on the command line.  Even when @command{ld} is
configured to support alternative object formats, you don't usually need
to specify this, as @command{ld} should be configured to expect as a
default input format the most usual format on each machine.
@var{input-format} is a text string, the name of a particular format
supported by the BFD libraries.  (You can list the available binary
formats with @samp{objdump -i}.)
@xref{BFD}.

You may want to use this option if you are linking files with an unusual
binary format.  You can also use @samp{-b} to switch formats explicitly (when
linking object files of different formats), by including
@samp{-b @var{input-format}} before each group of object files in a
particular format.

The default format is taken from the environment variable
@code{GNUTARGET}.
@ifset UsesEnvVars
@xref{Environment}.
@end ifset
You can also define the input format from a script, using the command
@code{TARGET};
@ifclear man
see @ref{Format Commands}.
@end ifclear
@end ifclear

@kindex -c @var{MRI-cmdfile}
@kindex --mri-script=@var{MRI-cmdfile}
@cindex compatibility, MRI
@item -c @var{MRI-commandfile}
@itemx --mri-script=@var{MRI-commandfile}
For compatibility with linkers produced by MRI, @command{ld} accepts script
files written in an alternate, restricted command language, described in
@ifclear man
@ref{MRI,,MRI Compatible Script Files}.
@end ifclear
@ifset man
the MRI Compatible Script Files section of GNU ld documentation.
@end ifset
Introduce MRI script files with
the option @samp{-c}; use the @samp{-T} option to run linker
scripts written in the general-purpose @command{ld} scripting language.
If @var{MRI-cmdfile} does not exist, @command{ld} looks for it in the directories
specified by any @samp{-L} options.

@cindex common allocation
@kindex -d
@kindex -dc
@kindex -dp
@item -d
@itemx -dc
@itemx -dp
These three options are equivalent; multiple forms are supported for
compatibility with other linkers.  They assign space to common symbols
even if a relocatable output file is specified (with @samp{-r}).  The
script command @code{FORCE_COMMON_ALLOCATION} has the same effect.
@xref{Miscellaneous Commands}.

@cindex entry point, from command line
@kindex -e @var{entry}
@kindex --entry=@var{entry}
@item -e @var{entry}
@itemx --entry=@var{entry}
Use @var{entry} as the explicit symbol for beginning execution of your
program, rather than the default entry point.  If there is no symbol
named @var{entry}, the linker will try to parse @var{entry} as a number,
and use that as the entry address (the number will be interpreted in
base 10; you may use a leading @samp{0x} for base 16, or a leading
@samp{0} for base 8).  @xref{Entry Point}, for a discussion of defaults
and other ways of specifying the entry point.

@cindex dynamic symbol table
@kindex -E
@kindex --export-dynamic
@item -E
@itemx --export-dynamic
When creating a dynamically linked executable, add all symbols to the
dynamic symbol table.  The dynamic symbol table is the set of symbols
which are visible from dynamic objects at run time.

If you do not use this option, the dynamic symbol table will normally
contain only those symbols which are referenced by some dynamic object
mentioned in the link.

If you use @code{dlopen} to load a dynamic object which needs to refer
back to the symbols defined by the program, rather than some other
dynamic object, then you will probably need to use this option when
linking the program itself.

You can also use the version script to control what symbols should
be added to the dynamic symbol table if the output format supports it.
See the description of @samp{--version-script} in @ref{VERSION}.

@cindex big-endian objects
@cindex endianness
@kindex -EB
@item -EB
Link big-endian objects.  This affects the default output format.

@cindex little-endian objects
@kindex -EL
@item -EL
Link little-endian objects.  This affects the default output format.

@kindex -f
@kindex --auxiliary
@item -f
@itemx --auxiliary @var{name}
When creating an ELF shared object, set the internal DT_AUXILIARY field
to the specified name.  This tells the dynamic linker that the symbol
table of the shared object should be used as an auxiliary filter on the
symbol table of the shared object @var{name}.

If you later link a program against this filter object, then, when you
run the program, the dynamic linker will see the DT_AUXILIARY field.  If
the dynamic linker resolves any symbols from the filter object, it will
first check whether there is a definition in the shared object
@var{name}.  If there is one, it will be used instead of the definition
in the filter object.  The shared object @var{name} need not exist.
Thus the shared object @var{name} may be used to provide an alternative
implementation of certain functions, perhaps for debugging or for
machine specific performance.

This option may be specified more than once.  The DT_AUXILIARY entries
will be created in the order in which they appear on the command line.

@kindex -F
@kindex --filter
@item -F @var{name}
@itemx --filter @var{name}
When creating an ELF shared object, set the internal DT_FILTER field to
the specified name.  This tells the dynamic linker that the symbol table
of the shared object which is being created should be used as a filter
on the symbol table of the shared object @var{name}.

If you later link a program against this filter object, then, when you
run the program, the dynamic linker will see the DT_FILTER field.  The
dynamic linker will resolve symbols according to the symbol table of the
filter object as usual, but it will actually link to the definitions
found in the shared object @var{name}.  Thus the filter object can be
used to select a subset of the symbols provided by the object
@var{name}.

Some older linkers used the @option{-F} option throughout a compilation
toolchain for specifying object-file format for both input and output
object files.  The @sc{gnu} linker uses other mechanisms for this
purpose: the @option{-b}, @option{--format}, @option{--oformat} options, the
@code{TARGET} command in linker scripts, and the @code{GNUTARGET}
environment variable.  The @sc{gnu} linker will ignore the @option{-F}
option when not creating an ELF shared object.

@cindex finalization function
@kindex -fini
@item -fini @var{name}
When creating an ELF executable or shared object, call NAME when the
executable or shared object is unloaded, by setting DT_FINI to the
address of the function.  By default, the linker uses @code{_fini} as
the function to call.

@kindex -g
@item -g
Ignored.  Provided for compatibility with other tools.

@kindex -G
@kindex --gpsize
@cindex object size
@item -G@var{value}
@itemx --gpsize=@var{value}
Set the maximum size of objects to be optimized using the GP register to
@var{size}.  This is only meaningful for object file formats such as
MIPS ECOFF which supports putting large and small objects into different
sections.  This is ignored for other object file formats.

@cindex runtime library name
@kindex -h@var{name}
@kindex -soname=@var{name}
@item -h@var{name}
@itemx -soname=@var{name}
When creating an ELF shared object, set the internal DT_SONAME field to
the specified name.  When an executable is linked with a shared object
which has a DT_SONAME field, then when the executable is run the dynamic
linker will attempt to load the shared object specified by the DT_SONAME
field rather than the using the file name given to the linker.

@kindex -i
@cindex incremental link
@item -i
Perform an incremental link (same as option @samp{-r}).

@cindex initialization function
@kindex -init
@item -init @var{name}
When creating an ELF executable or shared object, call NAME when the
executable or shared object is loaded, by setting DT_INIT to the address
of the function.  By default, the linker uses @code{_init} as the
function to call.

@cindex archive files, from cmd line
@kindex -l@var{archive}
@kindex --library=@var{archive}
@item -l@var{archive}
@itemx --library=@var{archive}
Add archive file @var{archive} to the list of files to link.  This
option may be used any number of times.  @command{ld} will search its
path-list for occurrences of @code{lib@var{archive}.a} for every
@var{archive} specified.

On systems which support shared libraries, @command{ld} may also search for
libraries with extensions other than @code{.a}.  Specifically, on ELF
and SunOS systems, @command{ld} will search a directory for a library with
an extension of @code{.so} before searching for one with an extension of
@code{.a}.  By convention, a @code{.so} extension indicates a shared
library.

The linker will search an archive only once, at the location where it is
specified on the command line.  If the archive defines a symbol which
was undefined in some object which appeared before the archive on the
command line, the linker will include the appropriate file(s) from the
archive.  However, an undefined symbol in an object appearing later on
the command line will not cause the linker to search the archive again.

See the @option{-(} option for a way to force the linker to search
archives multiple times.

You may list the same archive multiple times on the command line.

@ifset GENERIC
This type of archive searching is standard for Unix linkers.  However,
if you are using @command{ld} on AIX, note that it is different from the
behaviour of the AIX linker.
@end ifset

@cindex search directory, from cmd line
@kindex -L@var{dir}
@kindex --library-path=@var{dir}
@item -L@var{searchdir}
@itemx --library-path=@var{searchdir}
Add path @var{searchdir} to the list of paths that @command{ld} will search
for archive libraries and @command{ld} control scripts.  You may use this
option any number of times.  The directories are searched in the order
in which they are specified on the command line.  Directories specified
on the command line are searched before the default directories.  All
@option{-L} options apply to all @option{-l} options, regardless of the
order in which the options appear.

@ifset UsesEnvVars
The default set of paths searched (without being specified with
@samp{-L}) depends on which emulation mode @command{ld} is using, and in
some cases also on how it was configured.  @xref{Environment}.
@end ifset

The paths can also be specified in a link script with the
@code{SEARCH_DIR} command.  Directories specified this way are searched
at the point in which the linker script appears in the command line.

@cindex emulation
@kindex -m @var{emulation}
@item -m@var{emulation}
Emulate the @var{emulation} linker.  You can list the available
emulations with the @samp{--verbose} or @samp{-V} options.

If the @samp{-m} option is not used, the emulation is taken from the
@code{LDEMULATION} environment variable, if that is defined.

Otherwise, the default emulation depends upon how the linker was
configured.

@cindex link map
@kindex -M
@kindex --print-map
@item -M
@itemx --print-map
Print a link map to the standard output.  A link map provides
information about the link, including the following:

@itemize @bullet
@item
Where object files and symbols are mapped into memory.
@item
How common symbols are allocated.
@item
All archive members included in the link, with a mention of the symbol
which caused the archive member to be brought in.
@end itemize

@kindex -n
@cindex read-only text
@cindex NMAGIC
@kindex --nmagic
@item -n
@itemx --nmagic
Turn off page alignment of sections, and mark the output as
@code{NMAGIC} if possible.

@kindex -N
@kindex --omagic
@cindex read/write from cmd line
@cindex OMAGIC
@item -N
@itemx --omagic
Set the text and data sections to be readable and writable.  Also, do
not page-align the data segment.  If the output format supports Unix
style magic numbers, mark the output as @code{OMAGIC}.

@kindex -o @var{output}
@kindex --output=@var{output}
@cindex naming the output file
@item -o @var{output}
@itemx --output=@var{output}
Use @var{output} as the name for the program produced by @command{ld}; if this
option is not specified, the name @file{a.out} is used by default.  The
script command @code{OUTPUT} can also specify the output file name.

@kindex -O @var{level}
@cindex generating optimized output
@item -O @var{level}
If @var{level} is a numeric values greater than zero @command{ld} optimizes
the output.  This might take significantly longer and therefore probably
should only be enabled for the final binary.

@kindex -q
@kindex --emit-relocs
@cindex retain relocations in final executable
@item -q
@itemx --emit-relocs
Leave relocation sections and contents in fully linked exececutables.
Post link analysis and optimization tools may need this information in
order to perform correct modifications of executables.  This results
in larger executables.

This option is currently only supported on ELF platforms.

@cindex partial link
@cindex relocatable output
@kindex -r
@kindex --relocateable
@item -r
@itemx --relocateable
Generate relocatable output---i.e., generate an output file that can in
turn serve as input to @command{ld}.  This is often called @dfn{partial
linking}.  As a side effect, in environments that support standard Unix
magic numbers, this option also sets the output file's magic number to
@code{OMAGIC}.
@c ; see @option{-N}.
If this option is not specified, an absolute file is produced.  When
linking C++ programs, this option @emph{will not} resolve references to
constructors; to do that, use @samp{-Ur}.

When an input file does not have the same format as the output file,
partial linking is only supported if that input file does not contain any
relocations.  Different output formats can have further restrictions; for
example some @code{a.out}-based formats do not support partial linking
with input files in other formats at all.

This option does the same thing as @samp{-i}.

@kindex -R @var{file}
@kindex --just-symbols=@var{file}
@cindex symbol-only input
@item -R @var{filename}
@itemx --just-symbols=@var{filename}
Read symbol names and their addresses from @var{filename}, but do not
relocate it or include it in the output.  This allows your output file
to refer symbolically to absolute locations of memory defined in other
programs.  You may use this option more than once.

For compatibility with other ELF linkers, if the @option{-R} option is
followed by a directory name, rather than a file name, it is treated as
the @option{-rpath} option.

@kindex -s
@kindex --strip-all
@cindex strip all symbols
@item -s
@itemx --strip-all
Omit all symbol information from the output file.

@kindex -S
@kindex --strip-debug
@cindex strip debugger symbols
@item -S
@itemx --strip-debug
Omit debugger symbol information (but not all symbols) from the output file.

@kindex -t
@kindex --trace
@cindex input files, displaying
@item -t
@itemx --trace
Print the names of the input files as @command{ld} processes them.

@kindex -T @var{script}
@kindex --script=@var{script}
@cindex script files
@item -T @var{scriptfile}
@itemx --script=@var{scriptfile}
Use @var{scriptfile} as the linker script.  This script replaces
@command{ld}'s default linker script (rather than adding to it), so
@var{commandfile} must specify everything necessary to describe the
output file.  @xref{Scripts}.  If @var{scriptfile} does not exist in
the current directory, @code{ld} looks for it in the directories
specified by any preceding @samp{-L} options.  Multiple @samp{-T}
options accumulate.

@kindex -u @var{symbol}
@kindex --undefined=@var{symbol}
@cindex undefined symbol
@item -u @var{symbol}
@itemx --undefined=@var{symbol}
Force @var{symbol} to be entered in the output file as an undefined
symbol.  Doing this may, for example, trigger linking of additional
modules from standard libraries.  @samp{-u} may be repeated with
different option arguments to enter additional undefined symbols.  This
option is equivalent to the @code{EXTERN} linker script command.

@kindex -Ur
@cindex constructors
@item -Ur
For anything other than C++ programs, this option is equivalent to
@samp{-r}: it generates relocatable output---i.e., an output file that can in
turn serve as input to @command{ld}.  When linking C++ programs, @samp{-Ur}
@emph{does} resolve references to constructors, unlike @samp{-r}.
It does not work to use @samp{-Ur} on files that were themselves linked
with @samp{-Ur}; once the constructor table has been built, it cannot
be added to.  Use @samp{-Ur} only for the last partial link, and
@samp{-r} for the others.

@kindex --unique[=@var{SECTION}]
@item --unique[=@var{SECTION}]
Creates a separate output section for every input section matching
@var{SECTION}, or if the optional wildcard @var{SECTION} argument is
missing, for every orphan input section.  An orphan section is one not
specifically mentioned in a linker script.  You may use this option
multiple times on the command line;  It prevents the normal merging of
input sections with the same name, overriding output section assignments
in a linker script.

@kindex -v
@kindex -V
@kindex --version
@cindex version
@item -v
@itemx --version
@itemx -V
Display the version number for @command{ld}.  The @option{-V} option also
lists the supported emulations.

@kindex -x
@kindex --discard-all
@cindex deleting local symbols
@item -x
@itemx --discard-all
Delete all local symbols.

@kindex -X
@kindex --discard-locals
@cindex local symbols, deleting
@cindex L, deleting symbols beginning
@item -X
@itemx --discard-locals
Delete all temporary local symbols.  For most targets, this is all local
symbols whose names begin with @samp{L}.

@kindex -y @var{symbol}
@kindex --trace-symbol=@var{symbol}
@cindex symbol tracing
@item -y @var{symbol}
@itemx --trace-symbol=@var{symbol}
Print the name of each linked file in which @var{symbol} appears.  This
option may be given any number of times.  On many systems it is necessary
to prepend an underscore.

This option is useful when you have an undefined symbol in your link but
don't know where the reference is coming from.

@kindex -Y @var{path}
@item -Y @var{path}
Add @var{path} to the default library search path.  This option exists
for Solaris compatibility.

@kindex -z @var{keyword}
@item -z @var{keyword}
The recognized keywords are @code{initfirst}, @code{interpose},
@code{loadfltr}, @code{nodefaultlib}, @code{nodelete}, @code{nodlopen},
@code{nodump}, @code{now}, @code{origin}, @code{combreloc}, @code{nocombreloc} 
and @code{nocopyreloc}.
The other keywords are
ignored for Solaris compatibility. @code{initfirst} marks the object
to be initialized first at runtime before any other objects.
@code{interpose} marks the object that its symbol table interposes
before all symbols but the primary executable. @code{loadfltr} marks
the object that its filtees be processed immediately at runtime.
@code{nodefaultlib} marks the object that the search for dependencies
of this object will ignore any default library search paths.
@code{nodelete} marks the object shouldn't be unloaded at runtime.
@code{nodlopen} marks the object not available to @code{dlopen}.
@code{nodump} marks the object can not be dumped by @code{dldump}.
@code{now} marks the object with the non-lazy runtime binding.
@code{origin} marks the object may contain $ORIGIN.
@code{defs} disallows undefined symbols.
@code{combreloc} combines multiple reloc sections and sorts them
to make dynamic symbol lookup caching possible.
@code{nocombreloc} disables multiple reloc sections combining.
@code{nocopyreloc} disables production of copy relocs.

@kindex -(
@cindex groups of archives
@item -( @var{archives} -)
@itemx --start-group @var{archives} --end-group
The @var{archives} should be a list of archive files.  They may be
either explicit file names, or @samp{-l} options.

The specified archives are searched repeatedly until no new undefined
references are created.  Normally, an archive is searched only once in
the order that it is specified on the command line.  If a symbol in that
archive is needed to resolve an undefined symbol referred to by an
object in an archive that appears later on the command line, the linker
would not be able to resolve that reference.  By grouping the archives,
they all be searched repeatedly until all possible references are
resolved.

Using this option has a significant performance cost.  It is best to use
it only when there are unavoidable circular references between two or
more archives.

@kindex -assert @var{keyword}
@item -assert @var{keyword}
This option is ignored for SunOS compatibility.

@kindex -Bdynamic
@kindex -dy
@kindex -call_shared
@item -Bdynamic
@itemx -dy
@itemx -call_shared
Link against dynamic libraries.  This is only meaningful on platforms
for which shared libraries are supported.  This option is normally the
default on such platforms.  The different variants of this option are
for compatibility with various systems.  You may use this option
multiple times on the command line: it affects library searching for
@option{-l} options which follow it.

@kindex -Bgroup
@item -Bgroup
Set the @code{DF_1_GROUP} flag in the @code{DT_FLAGS_1} entry in the dynamic
section.  This causes the runtime linker to handle lookups in this
object and its dependencies to be performed only inside the group.
@option{--no-undefined} is implied.  This option is only meaningful on ELF
platforms which support shared libraries.

@kindex -Bstatic
@kindex -dn
@kindex -non_shared
@kindex -static
@item -Bstatic
@itemx -dn
@itemx -non_shared
@itemx -static
Do not link against shared libraries.  This is only meaningful on
platforms for which shared libraries are supported.  The different
variants of this option are for compatibility with various systems.  You
may use this option multiple times on the command line: it affects
library searching for @option{-l} options which follow it.

@kindex -Bsymbolic
@item -Bsymbolic
When creating a shared library, bind references to global symbols to the
definition within the shared library, if any.  Normally, it is possible
for a program linked against a shared library to override the definition
within the shared library.  This option is only meaningful on ELF
platforms which support shared libraries.

@kindex --check-sections
@kindex --no-check-sections
@item --check-sections
@itemx --no-check-sections
Asks the linker @emph{not} to check section addresses after they have
been assigned to see if there any overlaps.  Normally the linker will
perform this check, and if it finds any overlaps it will produce
suitable error messages.  The linker does know about, and does make
allowances for sections in overlays.  The default behaviour can be
restored by using the command line switch @samp{--check-sections}.

@cindex cross reference table
@kindex --cref
@item --cref
Output a cross reference table.  If a linker map file is being
generated, the cross reference table is printed to the map file.
Otherwise, it is printed on the standard output.

The format of the table is intentionally simple, so that it may be
easily processed by a script if necessary.  The symbols are printed out,
sorted by name.  For each symbol, a list of file names is given.  If the
symbol is defined, the first file listed is the location of the
definition.  The remaining files contain references to the symbol.

@cindex common allocation
@kindex --no-define-common
@item --no-define-common
This option inhibits the assignment of addresses to common symbols.
The script command @code{INHIBIT_COMMON_ALLOCATION} has the same effect.
@xref{Miscellaneous Commands}.

The @samp{--no-define-common} option allows decoupling
the decision to assign addresses to Common symbols from the choice
of the output file type; otherwise a non-Relocatable output type
forces assigning addresses to Common symbols.
Using @samp{--no-define-common} allows Common symbols that are referenced
from a shared library to be assigned addresses only in the main program.
This eliminates the unused duplicate space in the shared library,
and also prevents any possible confusion over resolving to the wrong
duplicate when there are many dynamic modules with specialized search
paths for runtime symbol resolution.

@cindex symbols, from command line
@kindex --defsym @var{symbol}=@var{exp}
@item --defsym @var{symbol}=@var{expression}
Create a global symbol in the output file, containing the absolute
address given by @var{expression}.  You may use this option as many
times as necessary to define multiple symbols in the command line.  A
limited form of arithmetic is supported for the @var{expression} in this
context: you may give a hexadecimal constant or the name of an existing
symbol, or use @code{+} and @code{-} to add or subtract hexadecimal
constants or symbols.  If you need more elaborate expressions, consider
using the linker command language from a script (@pxref{Assignments,,
Assignment: Symbol Definitions}).  @emph{Note:} there should be no white
space between @var{symbol}, the equals sign (``@key{=}''), and
@var{expression}.

@cindex demangling, from command line
@kindex --demangle[=@var{style}]
@kindex --no-demangle
@item --demangle[=@var{style}]
@itemx --no-demangle
These options control whether to demangle symbol names in error messages
and other output.  When the linker is told to demangle, it tries to
present symbol names in a readable fashion: it strips leading
underscores if they are used by the object file format, and converts C++
mangled symbol names into user readable names.  Different compilers have
different mangling styles.  The optional demangling style argument can be used
to choose an appropriate demangling style for your compiler.  The linker will
demangle by default unless the environment variable @samp{COLLECT_NO_DEMANGLE}
is set.  These options may be used to override the default.

@cindex dynamic linker, from command line
@kindex -I@var{file}
@kindex --dynamic-linker @var{file}
@item --dynamic-linker @var{file}
Set the name of the dynamic linker.  This is only meaningful when
generating dynamically linked ELF executables.  The default dynamic
linker is normally correct; don't use this unless you know what you are
doing.

@cindex MIPS embedded PIC code
@kindex --embedded-relocs
@item --embedded-relocs
This option is only meaningful when linking MIPS embedded PIC code,
generated by the -membedded-pic option to the @sc{gnu} compiler and
assembler.  It causes the linker to create a table which may be used at
runtime to relocate any data which was statically initialized to pointer
values.  See the code in testsuite/ld-empic for details.


@kindex --fatal-warnings
@item --fatal-warnings
Treat all warnings as errors.

@kindex --force-exe-suffix
@item  --force-exe-suffix
Make sure that an output file has a .exe suffix.

If a successfully built fully linked output file does not have a
@code{.exe} or @code{.dll} suffix, this option forces the linker to copy
the output file to one of the same name with a @code{.exe} suffix. This
option is useful when using unmodified Unix makefiles on a Microsoft
Windows host, since some versions of Windows won't run an image unless
it ends in a @code{.exe} suffix.

@kindex --gc-sections
@kindex --no-gc-sections
@cindex garbage collection
@item --no-gc-sections
@itemx --gc-sections
Enable garbage collection of unused input sections.  It is ignored on
targets that do not support this option.  This option is not compatible
with @samp{-r}, nor should it be used with dynamic linking.  The default
behaviour (of not performing this garbage collection) can be restored by
specifying @samp{--no-gc-sections} on the command line.

@cindex help
@cindex usage
@kindex --help
@item --help
Print a summary of the command-line options on the standard output and exit.

@kindex --target-help
@item --target-help
Print a summary of all target specific options on the standard output and exit.

@kindex -Map
@item -Map @var{mapfile}
Print a link map to the file @var{mapfile}.  See the description of the
@samp{-M} option, above.

@cindex memory usage
@kindex --no-keep-memory
@item --no-keep-memory
@command{ld} normally optimizes for speed over memory usage by caching the
symbol tables of input files in memory.  This option tells @command{ld} to
instead optimize for memory usage, by rereading the symbol tables as
necessary.  This may be required if @command{ld} runs out of memory space
while linking a large executable.

@kindex --no-undefined
@kindex -z defs
@item --no-undefined
@itemx -z defs
Normally when creating a non-symbolic shared library, undefined symbols
are allowed and left to be resolved by the runtime loader.  These options
disallows such undefined symbols.

@kindex --allow-shlib-undefined
@item --allow-shlib-undefined
Allow undefined symbols in shared objects even  when --no-undefined is
set. The net result will be that undefined symbols in regular objects
will still trigger an error, but undefined symbols in shared objects
will be ignored.  The implementation of no_undefined makes the
assumption that the runtime linker will choke on undefined symbols.
However there is at least one system (BeOS) where undefined symbols in
shared libraries is normal since the kernel patches them at load time to
select which function is most appropriate for the current architecture.
I.E. dynamically select an appropriate memset function.  Apparently it
is also normal for HPPA shared libraries to have undefined symbols.

@kindex --no-warn-mismatch
@item --no-warn-mismatch
Normally @command{ld} will give an error if you try to link together input
files that are mismatched for some reason, perhaps because they have
been compiled for different processors or for different endiannesses.
This option tells @command{ld} that it should silently permit such possible
errors.  This option should only be used with care, in cases when you
have taken some special action that ensures that the linker errors are
inappropriate.

@kindex --no-whole-archive
@item --no-whole-archive
Turn off the effect of the @option{--whole-archive} option for subsequent
archive files.

@cindex output file after errors
@kindex --noinhibit-exec
@item --noinhibit-exec
Retain the executable output file whenever it is still usable.
Normally, the linker will not produce an output file if it encounters
errors during the link process; it exits without writing an output file
when it issues any error whatsoever.

@kindex -nostdlib
@item -nostdlib
Only search library directories explicitly specified on the
command line.  Library directories specified in linker scripts
(including linker scripts specified on the command line) are ignored.

@ifclear SingleFormat
@kindex --oformat
@item --oformat @var{output-format}
@command{ld} may be configured to support more than one kind of object
file.  If your @command{ld} is configured this way, you can use the
@samp{--oformat} option to specify the binary format for the output
object file.  Even when @command{ld} is configured to support alternative
object formats, you don't usually need to specify this, as @command{ld}
should be configured to produce as a default output format the most
usual format on each machine.  @var{output-format} is a text string, the
name of a particular format supported by the BFD libraries.  (You can
list the available binary formats with @samp{objdump -i}.)  The script
command @code{OUTPUT_FORMAT} can also specify the output format, but
this option overrides it.  @xref{BFD}.
@end ifclear

@kindex -qmagic
@item -qmagic
This option is ignored for Linux compatibility.

@kindex -Qy
@item -Qy
This option is ignored for SVR4 compatibility.

@kindex --relax
@cindex synthesizing linker
@cindex relaxing addressing modes
@item --relax
An option with machine dependent effects.
@ifset GENERIC
This option is only supported on a few targets.
@end ifset
@ifset H8300
@xref{H8/300,,@command{ld} and the H8/300}.
@end ifset
@ifset I960
@xref{i960,, @command{ld} and the Intel 960 family}.
@end ifset


On some platforms, the @samp{--relax} option performs global
optimizations that become possible when the linker resolves addressing
in the program, such as relaxing address modes and synthesizing new
instructions in the output object file.

On some platforms these link time global optimizations may make symbolic
debugging of the resulting executable impossible.
@ifset GENERIC
This is known to be
the case for the Matsushita MN10200 and MN10300 family of processors.
@end ifset

@ifset GENERIC
On platforms where this is not supported, @samp{--relax} is accepted,
but ignored.
@end ifset

@cindex retaining specified symbols
@cindex stripping all but some symbols
@cindex symbols, retaining selectively
@item --retain-symbols-file @var{filename}
Retain @emph{only} the symbols listed in the file @var{filename},
discarding all others.  @var{filename} is simply a flat file, with one
symbol name per line.  This option is especially useful in environments
@ifset GENERIC
(such as VxWorks)
@end ifset
where a large global symbol table is accumulated gradually, to conserve
run-time memory.

@samp{--retain-symbols-file} does @emph{not} discard undefined symbols,
or symbols needed for relocations.

You may only specify @samp{--retain-symbols-file} once in the command
line.  It overrides @samp{-s} and @samp{-S}.

@ifset GENERIC
@item -rpath @var{dir}
@cindex runtime library search path
@kindex -rpath
Add a directory to the runtime library search path.  This is used when
linking an ELF executable with shared objects.  All @option{-rpath}
arguments are concatenated and passed to the runtime linker, which uses
them to locate shared objects at runtime.  The @option{-rpath} option is
also used when locating shared objects which are needed by shared
objects explicitly included in the link; see the description of the
@option{-rpath-link} option.  If @option{-rpath} is not used when linking an
ELF executable, the contents of the environment variable
@code{LD_RUN_PATH} will be used if it is defined.

The @option{-rpath} option may also be used on SunOS.  By default, on
SunOS, the linker will form a runtime search patch out of all the
@option{-L} options it is given.  If a @option{-rpath} option is used, the
runtime search path will be formed exclusively using the @option{-rpath}
options, ignoring the @option{-L} options.  This can be useful when using
gcc, which adds many @option{-L} options which may be on NFS mounted
filesystems.

For compatibility with other ELF linkers, if the @option{-R} option is
followed by a directory name, rather than a file name, it is treated as
the @option{-rpath} option.
@end ifset

@ifset GENERIC
@cindex link-time runtime library search path
@kindex -rpath-link
@item -rpath-link @var{DIR}
When using ELF or SunOS, one shared library may require another.  This
happens when an @code{ld -shared} link includes a shared library as one
of the input files.

When the linker encounters such a dependency when doing a non-shared,
non-relocatable link, it will automatically try to locate the required
shared library and include it in the link, if it is not included
explicitly.  In such a case, the @option{-rpath-link} option
specifies the first set of directories to search.  The
@option{-rpath-link} option may specify a sequence of directory names
either by specifying a list of names separated by colons, or by
appearing multiple times.

This option should be used with caution as it overrides the search path
that may have been hard compiled into a shared library. In such a case it
is possible to use unintentionally a different search path than the
runtime linker would do.

The linker uses the following search paths to locate required shared
libraries.
@enumerate
@item
Any directories specified by @option{-rpath-link} options.
@item
Any directories specified by @option{-rpath} options.  The difference
between @option{-rpath} and @option{-rpath-link} is that directories
specified by @option{-rpath} options are included in the executable and
used at runtime, whereas the @option{-rpath-link} option is only effective
at link time. It is for the native linker only.
@item
On an ELF system, if the @option{-rpath} and @code{rpath-link} options
were not used, search the contents of the environment variable
@code{LD_RUN_PATH}. It is for the native linker only.
@item
On SunOS, if the @option{-rpath} option was not used, search any
directories specified using @option{-L} options.
@item
For a native linker, the contents of the environment variable
@code{LD_LIBRARY_PATH}.
@item
For a native ELF linker, the directories in @code{DT_RUNPATH} or
@code{DT_RPATH} of a shared library are searched for shared
libraries needed by it. The @code{DT_RPATH} entries are ignored if
@code{DT_RUNPATH} entries exist.
@item
The default directories, normally @file{/lib} and @file{/usr/lib}.
@item
For a native linker on an ELF system, if the file @file{/etc/ld.so.conf}
exists, the list of directories found in that file.
@end enumerate

If the required shared library is not found, the linker will issue a
warning and continue with the link.
@end ifset

@kindex -shared
@kindex -Bshareable
@item -shared
@itemx -Bshareable
@cindex shared libraries
Create a shared library.  This is currently only supported on ELF, XCOFF
and SunOS platforms.  On SunOS, the linker will automatically create a
shared library if the @option{-e} option is not used and there are
undefined symbols in the link.

@item --sort-common
@kindex --sort-common
This option tells @command{ld} to sort the common symbols by size when it
places them in the appropriate output sections.  First come all the one
byte symbols, then all the two byte, then all the four byte, and then
everything else.  This is to prevent gaps between symbols due to
alignment constraints.

@kindex --split-by-file
@item --split-by-file [@var{size}]
Similar to @option{--split-by-reloc} but creates a new output section for
each input file when @var{size} is reached.  @var{size} defaults to a
size of 1 if not given.

@kindex --split-by-reloc
@item --split-by-reloc [@var{count}]
Tries to creates extra sections in the output file so that no single
output section in the file contains more than @var{count} relocations.
This is useful when generating huge relocatable files for downloading into
certain real time kernels with the COFF object file format; since COFF
cannot represent more than 65535 relocations in a single section.  Note
that this will fail to work with object file formats which do not
support arbitrary sections.  The linker will not split up individual
input sections for redistribution, so if a single input section contains
more than @var{count} relocations one output section will contain that
many relocations.  @var{count} defaults to a value of 32768.

@kindex --stats
@item --stats
Compute and display statistics about the operation of the linker, such
as execution time and memory usage.

@kindex --traditional-format
@cindex traditional format
@item --traditional-format
For some targets, the output of @command{ld} is different in some ways from
the output of some existing linker.  This switch requests @command{ld} to
use the traditional format instead.

@cindex dbx
For example, on SunOS, @command{ld} combines duplicate entries in the
symbol string table.  This can reduce the size of an output file with
full debugging information by over 30 percent.  Unfortunately, the SunOS
@code{dbx} program can not read the resulting program (@code{gdb} has no
trouble).  The @samp{--traditional-format} switch tells @command{ld} to not
combine duplicate entries.

@kindex --section-start @var{sectionname}=@var{org}
@item --section-start @var{sectionname}=@var{org}
Locate a section in the output file at the absolute
address given by @var{org}.  You may use this option as many
times as necessary to locate multiple sections in the command
line.
@var{org} must be a single hexadecimal integer;
for compatibility with other linkers, you may omit the leading
@samp{0x} usually associated with hexadecimal values.  @emph{Note:} there
should be no white space between @var{sectionname}, the equals
sign (``@key{=}''), and @var{org}.

@kindex -Tbss @var{org}
@kindex -Tdata @var{org}
@kindex -Ttext @var{org}
@cindex segment origins, cmd line
@item -Tbss @var{org}
@itemx -Tdata @var{org}
@itemx -Ttext @var{org}
Use @var{org} as the starting address for---respectively---the
@code{bss}, @code{data}, or the @code{text} segment of the output file.
@var{org} must be a single hexadecimal integer;
for compatibility with other linkers, you may omit the leading
@samp{0x} usually associated with hexadecimal values.

@kindex --verbose
@cindex verbose
@item --dll-verbose
@itemx --verbose
Display the version number for @command{ld} and list the linker emulations
supported.  Display which input files can and cannot be opened.  Display
the linker script being used by the linker.

@kindex --version-script=@var{version-scriptfile}
@cindex version script, symbol versions
@itemx --version-script=@var{version-scriptfile}
Specify the name of a version script to the linker.  This is typically
used when creating shared libraries to specify additional information
about the version heirarchy for the library being created.  This option
is only meaningful on ELF platforms which support shared libraries.
@xref{VERSION}.

@kindex --warn-common
@cindex warnings, on combining symbols
@cindex combining symbols, warnings on
@item --warn-common
Warn when a common symbol is combined with another common symbol or with
a symbol definition.  Unix linkers allow this somewhat sloppy practice,
but linkers on some other operating systems do not.  This option allows
you to find potential problems from combining global symbols.
Unfortunately, some C libraries use this practice, so you may get some
warnings about symbols in the libraries as well as in your programs.

There are three kinds of global symbols, illustrated here by C examples:

@table @samp
@item int i = 1;
A definition, which goes in the initialized data section of the output
file.

@item extern int i;
An undefined reference, which does not allocate space.
There must be either a definition or a common symbol for the
variable somewhere.

@item int i;
A common symbol.  If there are only (one or more) common symbols for a
variable, it goes in the uninitialized data area of the output file.
The linker merges multiple common symbols for the same variable into a
single symbol.  If they are of different sizes, it picks the largest
size.  The linker turns a common symbol into a declaration, if there is
a definition of the same variable.
@end table

The @samp{--warn-common} option can produce five kinds of warnings.
Each warning consists of a pair of lines: the first describes the symbol
just encountered, and the second describes the previous symbol
encountered with the same name.  One or both of the two symbols will be
a common symbol.

@enumerate
@item
Turning a common symbol into a reference, because there is already a
definition for the symbol.
@smallexample
@var{file}(@var{section}): warning: common of `@var{symbol}'
   overridden by definition
@var{file}(@var{section}): warning: defined here
@end smallexample

@item
Turning a common symbol into a reference, because a later definition for
the symbol is encountered.  This is the same as the previous case,
except that the symbols are encountered in a different order.
@smallexample
@var{file}(@var{section}): warning: definition of `@var{symbol}'
   overriding common
@var{file}(@var{section}): warning: common is here
@end smallexample

@item
Merging a common symbol with a previous same-sized common symbol.
@smallexample
@var{file}(@var{section}): warning: multiple common
   of `@var{symbol}'
@var{file}(@var{section}): warning: previous common is here
@end smallexample

@item
Merging a common symbol with a previous larger common symbol.
@smallexample
@var{file}(@var{section}): warning: common of `@var{symbol}'
   overridden by larger common
@var{file}(@var{section}): warning: larger common is here
@end smallexample

@item
Merging a common symbol with a previous smaller common symbol.  This is
the same as the previous case, except that the symbols are
encountered in a different order.
@smallexample
@var{file}(@var{section}): warning: common of `@var{symbol}'
   overriding smaller common
@var{file}(@var{section}): warning: smaller common is here
@end smallexample
@end enumerate

@kindex --warn-constructors
@item --warn-constructors
Warn if any global constructors are used.  This is only useful for a few
object file formats.  For formats like COFF or ELF, the linker can not
detect the use of global constructors.

@kindex --warn-multiple-gp
@item --warn-multiple-gp
Warn if multiple global pointer values are required in the output file.
This is only meaningful for certain processors, such as the Alpha.
Specifically, some processors put large-valued constants in a special
section.  A special register (the global pointer) points into the middle
of this section, so that constants can be loaded efficiently via a
base-register relative addressing mode.  Since the offset in
base-register relative mode is fixed and relatively small (e.g., 16
bits), this limits the maximum size of the constant pool.  Thus, in
large programs, it is often necessary to use multiple global pointer
values in order to be able to address all possible constants.  This
option causes a warning to be issued whenever this case occurs.

@kindex --warn-once
@cindex warnings, on undefined symbols
@cindex undefined symbols, warnings on
@item --warn-once
Only warn once for each undefined symbol, rather than once per module
which refers to it.

@kindex --warn-section-align
@cindex warnings, on section alignment
@cindex section alignment, warnings on
@item --warn-section-align
Warn if the address of an output section is changed because of
alignment.  Typically, the alignment will be set by an input section.
The address will only be changed if it not explicitly specified; that
is, if the @code{SECTIONS} command does not specify a start address for
the section (@pxref{SECTIONS}).

@kindex --whole-archive
@cindex including an entire archive
@item --whole-archive
For each archive mentioned on the command line after the
@option{--whole-archive} option, include every object file in the archive
in the link, rather than searching the archive for the required object
files.  This is normally used to turn an archive file into a shared
library, forcing every object to be included in the resulting shared
library.  This option may be used more than once.

Two notes when using this option from gcc: First, gcc doesn't know
about this option, so you have to use @option{-Wl,-whole-archive}.
Second, don't forget to use @option{-Wl,-no-whole-archive} after your
list of archives, because gcc will add its own list of archives to
your link and you may not want this flag to affect those as well.

@kindex --wrap
@item --wrap @var{symbol}
Use a wrapper function for @var{symbol}.  Any undefined reference to
@var{symbol} will be resolved to @code{__wrap_@var{symbol}}.  Any
undefined reference to @code{__real_@var{symbol}} will be resolved to
@var{symbol}.

This can be used to provide a wrapper for a system function.  The
wrapper function should be called @code{__wrap_@var{symbol}}.  If it
wishes to call the system function, it should call
@code{__real_@var{symbol}}.

Here is a trivial example:

@smallexample
void *
__wrap_malloc (int c)
@{
  printf ("malloc called with %ld\n", c);
  return __real_malloc (c);
@}
@end smallexample

If you link other code with this file using @option{--wrap malloc}, then
all calls to @code{malloc} will call the function @code{__wrap_malloc}
instead.  The call to @code{__real_malloc} in @code{__wrap_malloc} will
call the real @code{malloc} function.

You may wish to provide a @code{__real_malloc} function as well, so that
links without the @option{--wrap} option will succeed.  If you do this,
you should not put the definition of @code{__real_malloc} in the same
file as @code{__wrap_malloc}; if you do, the assembler may resolve the
call before the linker has a chance to wrap it to @code{malloc}.

@kindex --enable-new-dtags
@kindex --disable-new-dtags
@item --enable-new-dtags
@itemx --disable-new-dtags
This linker can create the new dynamic tags in ELF. But the older ELF
systems may not understand them. If you specify
@option{--enable-new-dtags}, the dynamic tags will be created as needed.
If you specify @option{--disable-new-dtags}, no new dynamic tags will be
created. By default, the new dynamic tags are not created. Note that
those options are only available for ELF systems.

@end table

@c man end

@subsection Options specific to i386 PE targets

@c man begin OPTIONS

The i386 PE linker supports the @option{-shared} option, which causes
the output to be a dynamically linked library (DLL) instead of a
normal executable.  You should name the output @code{*.dll} when you
use this option.  In addition, the linker fully supports the standard
@code{*.def} files, which may be specified on the linker command line
like an object file (in fact, it should precede archives it exports
symbols from, to ensure that they get linked in, just like a normal
object file).

In addition to the options common to all targets, the i386 PE linker
support additional command line options that are specific to the i386
PE target.  Options that take values may be separated from their
values by either a space or an equals sign.

@table @gcctabopt

@kindex --add-stdcall-alias
@item --add-stdcall-alias
If given, symbols with a stdcall suffix (@@@var{nn}) will be exported
as-is and also with the suffix stripped.

@kindex --base-file
@item --base-file @var{file}
Use @var{file} as the name of a file in which to save the base
addresses of all the relocations needed for generating DLLs with
@file{dlltool}.

@kindex --dll
@item --dll
Create a DLL instead of a regular executable.  You may also use
@option{-shared} or specify a @code{LIBRARY} in a given @code{.def}
file.

@kindex --enable-stdcall-fixup
@kindex --disable-stdcall-fixup
@item --enable-stdcall-fixup
@itemx --disable-stdcall-fixup
If the link finds a symbol that it cannot resolve, it will attempt to
do "fuzzy linking" by looking for another defined symbol that differs
only in the format of the symbol name (cdecl vs stdcall) and will
resolve that symbol by linking to the match.  For example, the
undefined symbol @code{_foo} might be linked to the function
@code{_foo@@12}, or the undefined symbol @code{_bar@@16} might be linked
to the function @code{_bar}.  When the linker does this, it prints a
warning, since it normally should have failed to link, but sometimes
import libraries generated from third-party dlls may need this feature
to be usable.  If you specify @option{--enable-stdcall-fixup}, this
feature is fully enabled and warnings are not printed.  If you specify
@option{--disable-stdcall-fixup}, this feature is disabled and such
mismatches are considered to be errors.

@cindex DLLs, creating
@kindex --export-all-symbols
@item --export-all-symbols
If given, all global symbols in the objects used to build a DLL will
be exported by the DLL.  Note that this is the default if there
otherwise wouldn't be any exported symbols.  When symbols are
explicitly exported via DEF files or implicitly exported via function
attributes, the default is to not export anything else unless this
option is given.  Note that the symbols @code{DllMain@@12},
@code{DllEntryPoint@@0}, @code{DllMainCRTStartup@@12}, and 
@code{impure_ptr} will not be automatically
exported.  Also, symbols imported from other DLLs will not be 
re-exported, nor will symbols specifying the DLL's internal layout 
such as those beginning with @code{_head_} or ending with 
@code{_iname}.  In addition, no symbols from @code{libgcc}, 
@code{libstd++}, @code{libmingw32}, or @code{crtX.o} will be exported.
Symbols whose names begin with @code{__rtti_} or @code{__builtin_} will
not be exported, to help with C++ DLLs.  Finally, there is an
extensive list of cygwin-private symbols that are not exported 
(obviously, this applies on when building DLLs for cygwin targets).
These cygwin-excludes are: @code{_cygwin_dll_entry@@12}, 
@code{_cygwin_crt0_common@@8}, @code{_cygwin_noncygwin_dll_entry@@12},
@code{_fmode}, @code{_impure_ptr}, @code{cygwin_attach_dll}, 
@code{cygwin_premain0}, @code{cygwin_premain1}, @code{cygwin_premain2},
@code{cygwin_premain3}, and @code{environ}. 

@kindex --exclude-symbols
@item --exclude-symbols @var{symbol},@var{symbol},...
Specifies a list of symbols which should not be automatically
exported.  The symbol names may be delimited by commas or colons.

@kindex --file-alignment
@item --file-alignment
Specify the file alignment.  Sections in the file will always begin at
file offsets which are multiples of this number.  This defaults to
512.

@cindex heap size
@kindex --heap
@item --heap @var{reserve}
@itemx --heap @var{reserve},@var{commit}
Specify the amount of memory to reserve (and optionally commit) to be
used as heap for this program.  The default is 1Mb reserved, 4K
committed.

@cindex image base
@kindex --image-base
@item --image-base @var{value}
Use @var{value} as the base address of your program or dll.  This is
the lowest memory location that will be used when your program or dll
is loaded.  To reduce the need to relocate and improve performance of
your dlls, each should have a unique base address and not overlap any
other dlls.  The default is 0x400000 for executables, and 0x10000000
for dlls.

@kindex --kill-at
@item --kill-at
If given, the stdcall suffixes (@@@var{nn}) will be stripped from
symbols before they are exported.

@kindex --major-image-version
@item --major-image-version @var{value}
Sets the major number of the "image version".  Defaults to 1.

@kindex --major-os-version
@item --major-os-version @var{value}
Sets the major number of the "os version".  Defaults to 4.

@kindex --major-subsystem-version
@item --major-subsystem-version @var{value}
Sets the major number of the "subsystem version".  Defaults to 4.

@kindex --minor-image-version
@item --minor-image-version @var{value}
Sets the minor number of the "image version".  Defaults to 0.

@kindex --minor-os-version
@item --minor-os-version @var{value}
Sets the minor number of the "os version".  Defaults to 0.

@kindex --minor-subsystem-version
@item --minor-subsystem-version @var{value}
Sets the minor number of the "subsystem version".  Defaults to 0.

@cindex DEF files, creating
@cindex DLLs, creating
@kindex --output-def
@item --output-def @var{file}
The linker will create the file @var{file} which will contain a DEF
file corresponding to the DLL the linker is generating.  This DEF file
(which should be called @code{*.def}) may be used to create an import
library with @code{dlltool} or may be used as a reference to
automatically or implicitly exported symbols.

@cindex DLLs, creating
@kindex --out-implib
@item --out-implib @var{file}
The linker will create the file @var{file} which will contain an
import lib corresponding to the DLL the linker is generating. This
import lib (which should be called @code{*.dll.a} or @code{*.a}
may be used to link clients against the generated DLL; this behavior
makes it possible to skip a separate @code{dlltool} import library
creation step.

@kindex --enable-auto-image-base
@item --enable-auto-image-base
Automatically choose the image base for DLLs, unless one is specified
using the @code{--image-base} argument.  By using a hash generated
from the dllname to create unique image bases for each DLL, in-memory
collisions and relocations which can delay program execution are
avoided.

@kindex --disable-auto-image-base
@item --disable-auto-image-base
Do not automatically generate a unique image base.  If there is no
user-specified image base (@code{--image-base}) then use the platform
default.

@cindex DLLs, linking to
@kindex --dll-search-prefix
@item --dll-search-prefix @var{string}
When linking dynamically to a dll without an import library, i
search for @code{<string><basename>.dll} in preference to 
@code{lib<basename>.dll}. This behavior allows easy distinction
between DLLs built for the various "subplatforms": native, cygwin,
uwin, pw, etc.  For instance, cygwin DLLs typically use
@code{--dll-search-prefix=cyg}. 

@kindex --enable-auto-import
@item --enable-auto-import
Do sophisticated linking of @code{_symbol} to @code{__imp__symbol} for 
DATA imports from DLLs, and create the necessary thunking symbols when 
building the DLLs with those DATA exports.  This generally will 'just 
work' -- but sometimes you may see this message:

"variable '<var>' can't be auto-imported. Please read the 
documentation for ld's @code{--enable-auto-import} for details."

This message occurs when some (sub)expression accesses an address 
ultimately given by the sum of two constants (Win32 import tables only 
allow one).  Instances where this may occur include accesses to member 
fields of struct variables imported from a DLL, as well as using a 
constant index into an array variable imported from a DLL.  Any 
multiword variable (arrays, structs, long long, etc) may trigger
this error condition.  However, regardless of the exact data type
of the offending exported variable, ld will always detect it, issue
the warning, and exit.

There are several ways to address this difficulty, regardless of the
data type of the exported variable:

One solution is to force one of the 'constants' to be a variable -- 
that is, unknown and un-optimizable at compile time.  For arrays, 
there are two possibilities: a) make the indexee (the array's address) 
a variable, or b) make the 'constant' index a variable.  Thus:

@example
extern type extern_array[];
extern_array[1] --> 
   @{ volatile type *t=extern_array; t[1] @}
@end example

or

@example
extern type extern_array[];
extern_array[1] --> 
   @{ volatile int t=1; extern_array[t] @}
@end example

For structs (and most other multiword data types) the only option 
is to make the struct itself (or the long long, or the ...) variable:

@example
extern struct s extern_struct;
extern_struct.field --> 
   @{ volatile struct s *t=&extern_struct; t->field @}
@end example

or

@example
extern long long extern_ll;
extern_ll -->
  @{ volatile long long * local_ll=&extern_ll; *local_ll @}
@end example

A second method of dealing with this difficulty is to abandon
'auto-import' for the offending symbol and mark it with 
@code{__declspec(dllimport)}.  However, in practice that
requires using compile-time #defines to indicate whether you are
building a DLL, building client code that will link to the DLL, or 
merely building/linking to a static library.   In making the choice 
between the various methods of resolving the 'direct address with 
constant offset' problem, you should consider typical real-world usage:

Original:
@example
--foo.h
extern int arr[];
--foo.c
#include "foo.h"
void main(int argc, char **argv)@{
  printf("%d\n",arr[1]);
@}
@end example

Solution 1:
@example
--foo.h
extern int arr[];
--foo.c
#include "foo.h"
void main(int argc, char **argv)@{
  /* This workaround is for win32 and cygwin; do not "optimize" */
  volatile int *parr = arr;
  printf("%d\n",parr[1]);
@}
@end example

Solution 2:
@example
--foo.h
/* Note: auto-export is assumed (no __declspec(dllexport)) */
#if (defined(_WIN32) || defined(__CYGWIN__)) && \
  !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
#define FOO_IMPORT __declspec(dllimport)
#else
#define FOO_IMPORT
#endif
extern FOO_IMPORT int arr[];
--foo.c
#include "foo.h"
void main(int argc, char **argv)@{
  printf("%d\n",arr[1]);
@}
@end example

A third way to avoid this problem is to re-code your 
library to use a functional interface rather than a data interface
for the offending variables (e.g. set_foo() and get_foo() accessor
functions).

@kindex --disable-auto-import
@item --disable-auto-import
Do not attempt to do sophisticalted linking of @code{_symbol} to 
@code{__imp__symbol} for DATA imports from DLLs.

@kindex --enable-extra-pe-debug
@item --enable-extra-pe-debug
Show additional debug info related to auto-import symbol thunking.

@kindex --section-alignment
@item --section-alignment
Sets the section alignment.  Sections in memory will always begin at
addresses which are a multiple of this number.  Defaults to 0x1000.

@cindex stack size
@kindex --stack
@item --stack @var{reserve}
@itemx --stack @var{reserve},@var{commit}
Specify the amount of memory to reserve (and optionally commit) to be
used as stack for this program.  The default is 2Mb reserved, 4K
committed.

@kindex --subsystem
@item --subsystem @var{which}
@itemx --subsystem @var{which}:@var{major}
@itemx --subsystem @var{which}:@var{major}.@var{minor}
Specifies the subsystem under which your program will execute.  The
legal values for @var{which} are @code{native}, @code{windows},
@code{console}, and @code{posix}.  You may optionally set the
subsystem version also.

@end table

@c man end

@ifset UsesEnvVars
@node Environment
@section Environment Variables

@c man begin ENVIRONMENT

You can change the behavior of @command{ld} with the environment variables
@code{GNUTARGET}, @code{LDEMULATION}, and @code{COLLECT_NO_DEMANGLE}.

@kindex GNUTARGET
@cindex default input format
@code{GNUTARGET} determines the input-file object format if you don't
use @samp{-b} (or its synonym @samp{--format}).  Its value should be one
of the BFD names for an input format (@pxref{BFD}).  If there is no
@code{GNUTARGET} in the environment, @command{ld} uses the natural format
of the target. If @code{GNUTARGET} is set to @code{default} then BFD
attempts to discover the input format by examining binary input files;
this method often succeeds, but there are potential ambiguities, since
there is no method of ensuring that the magic number used to specify
object-file formats is unique.  However, the configuration procedure for
BFD on each system places the conventional format for that system first
in the search-list, so ambiguities are resolved in favor of convention.

@kindex LDEMULATION
@cindex default emulation
@cindex emulation, default
@code{LDEMULATION} determines the default emulation if you don't use the
@samp{-m} option.  The emulation can affect various aspects of linker
behaviour, particularly the default linker script.  You can list the
available emulations with the @samp{--verbose} or @samp{-V} options.  If
the @samp{-m} option is not used, and the @code{LDEMULATION} environment
variable is not defined, the default emulation depends upon how the
linker was configured.

@kindex COLLECT_NO_DEMANGLE
@cindex demangling, default
Normally, the linker will default to demangling symbols.  However, if
@code{COLLECT_NO_DEMANGLE} is set in the environment, then it will
default to not demangling symbols.  This environment variable is used in
a similar fashion by the @code{gcc} linker wrapper program.  The default
may be overridden by the @samp{--demangle} and @samp{--no-demangle}
options.

@c man end
@end ifset

@node Scripts
@chapter Linker Scripts

@cindex scripts
@cindex linker scripts
@cindex command files
Every link is controlled by a @dfn{linker script}.  This script is
written in the linker command language.

The main purpose of the linker script is to describe how the sections in
the input files should be mapped into the output file, and to control
the memory layout of the output file.  Most linker scripts do nothing
more than this.  However, when necessary, the linker script can also
direct the linker to perform many other operations, using the commands
described below.

The linker always uses a linker script.  If you do not supply one
yourself, the linker will use a default script that is compiled into the
linker executable.  You can use the @samp{--verbose} command line option
to display the default linker script.  Certain command line options,
such as @samp{-r} or @samp{-N}, will affect the default linker script.

You may supply your own linker script by using the @samp{-T} command
line option.  When you do this, your linker script will replace the
default linker script.

You may also use linker scripts implicitly by naming them as input files
to the linker, as though they were files to be linked.  @xref{Implicit
Linker Scripts}.

@menu
* Basic Script Concepts::	Basic Linker Script Concepts
* Script Format::		Linker Script Format
* Simple Example::		Simple Linker Script Example
* Simple Commands::		Simple Linker Script Commands
* Assignments::			Assigning Values to Symbols
* SECTIONS::			SECTIONS Command
* MEMORY::			MEMORY Command
* PHDRS::			PHDRS Command
* VERSION::			VERSION Command
* Expressions::			Expressions in Linker Scripts
* Implicit Linker Scripts::	Implicit Linker Scripts
@end menu

@node Basic Script Concepts
@section Basic Linker Script Concepts
@cindex linker script concepts
We need to define some basic concepts and vocabulary in order to
describe the linker script language.

The linker combines input files into a single output file.  The output
file and each input file are in a special data format known as an
@dfn{object file format}.  Each file is called an @dfn{object file}.
The output file is often called an @dfn{executable}, but for our
purposes we will also call it an object file.  Each object file has,
among other things, a list of @dfn{sections}.  We sometimes refer to a
section in an input file as an @dfn{input section}; similarly, a section
in the output file is an @dfn{output section}.

Each section in an object file has a name and a size.  Most sections
also have an associated block of data, known as the @dfn{section
contents}.  A section may be marked as @dfn{loadable}, which mean that
the contents should be loaded into memory when the output file is run.
A section with no contents may be @dfn{allocatable}, which means that an
area in memory should be set aside, but nothing in particular should be
loaded there (in some cases this memory must be zeroed out).  A section
which is neither loadable nor allocatable typically contains some sort
of debugging information.

Every loadable or allocatable output section has two addresses.  The
first is the @dfn{VMA}, or virtual memory address.  This is the address
the section will have when the output file is run.  The second is the
@dfn{LMA}, or load memory address.  This is the address at which the
section will be loaded.  In most cases the two addresses will be the
same.  An example of when they might be different is when a data section
is loaded into ROM, and then copied into RAM when the program starts up
(this technique is often used to initialize global variables in a ROM
based system).  In this case the ROM address would be the LMA, and the
RAM address would be the VMA.

You can see the sections in an object file by using the @code{objdump}
program with the @samp{-h} option.

Every object file also has a list of @dfn{symbols}, known as the
@dfn{symbol table}.  A symbol may be defined or undefined.  Each symbol
has a name, and each defined symbol has an address, among other
information.  If you compile a C or C++ program into an object file, you
will get a defined symbol for every defined function and global or
static variable.  Every undefined function or global variable which is
referenced in the input file will become an undefined symbol.

You can see the symbols in an object file by using the @code{nm}
program, or by using the @code{objdump} program with the @samp{-t}
option.

@node Script Format
@section Linker Script Format
@cindex linker script format
Linker scripts are text files.

You write a linker script as a series of commands.  Each command is
either a keyword, possibly followed by arguments, or an assignment to a
symbol.  You may separate commands using semicolons.  Whitespace is
generally ignored.

Strings such as file or format names can normally be entered directly.
If the file name contains a character such as a comma which would
otherwise serve to separate file names, you may put the file name in
double quotes.  There is no way to use a double quote character in a
file name.

You may include comments in linker scripts just as in C, delimited by
@samp{/*} and @samp{*/}.  As in C, comments are syntactically equivalent
to whitespace.

@node Simple Example
@section Simple Linker Script Example
@cindex linker script example
@cindex example of linker script
Many linker scripts are fairly simple.

The simplest possible linker script has just one command:
@samp{SECTIONS}.  You use the @samp{SECTIONS} command to describe the
memory layout of the output file.

The @samp{SECTIONS} command is a powerful command.  Here we will
describe a simple use of it.  Let's assume your program consists only of
code, initialized data, and uninitialized data.  These will be in the
@samp{.text}, @samp{.data}, and @samp{.bss} sections, respectively.
Let's assume further that these are the only sections which appear in
your input files.

For this example, let's say that the code should be loaded at address
0x10000, and that the data should start at address 0x8000000.  Here is a
linker script which will do that:
@smallexample
SECTIONS
@{
  . = 0x10000;
  .text : @{ *(.text) @}
  . = 0x8000000;
  .data : @{ *(.data) @}
  .bss : @{ *(.bss) @}
@}
@end smallexample

You write the @samp{SECTIONS} command as the keyword @samp{SECTIONS},
followed by a series of symbol assignments and output section
descriptions enclosed in curly braces.

The first line inside the @samp{SECTIONS} command of the above example
sets the value of the special symbol @samp{.}, which is the location
counter.  If you do not specify the address of an output section in some
other way (other ways are described later), the address is set from the
current value of the location counter.  The location counter is then
incremented by the size of the output section.  At the start of the
@samp{SECTIONS} command, the location counter has the value @samp{0}.

The second line defines an output section, @samp{.text}.  The colon is
required syntax which may be ignored for now.  Within the curly braces
after the output section name, you list the names of the input sections
which should be placed into this output section.  The @samp{*} is a
wildcard which matches any file name.  The expression @samp{*(.text)}
means all @samp{.text} input sections in all input files.

Since the location counter is @samp{0x10000} when the output section
@samp{.text} is defined, the linker will set the address of the
@samp{.text} section in the output file to be @samp{0x10000}.

The remaining lines define the @samp{.data} and @samp{.bss} sections in
the output file.  The linker will place the @samp{.data} output section
at address @samp{0x8000000}.  After the linker places the @samp{.data}
output section, the value of the location counter will be
@samp{0x8000000} plus the size of the @samp{.data} output section.  The
effect is that the linker will place the @samp{.bss} output section
immediately after the @samp{.data} output section in memory

The linker will ensure that each output section has the required
alignment, by increasing the location counter if necessary.  In this
example, the specified addresses for the @samp{.text} and @samp{.data}
sections will probably satisfy any alignment constraints, but the linker
may have to create a small gap between the @samp{.data} and @samp{.bss}
sections.

That's it!  That's a simple and complete linker script.

@node Simple Commands
@section Simple Linker Script Commands
@cindex linker script simple commands
In this section we describe the simple linker script commands.

@menu
* Entry Point::			Setting the entry point
* File Commands::		Commands dealing with files
@ifclear SingleFormat
* Format Commands::		Commands dealing with object file formats
@end ifclear

* Miscellaneous Commands::	Other linker script commands
@end menu

@node Entry Point
@subsection Setting the entry point
@kindex ENTRY(@var{symbol})
@cindex start of execution
@cindex first instruction
@cindex entry point
The first instruction to execute in a program is called the @dfn{entry
point}.  You can use the @code{ENTRY} linker script command to set the
entry point.  The argument is a symbol name:
@smallexample
ENTRY(@var{symbol})
@end smallexample

There are several ways to set the entry point.  The linker will set the
entry point by trying each of the following methods in order, and
stopping when one of them succeeds:
@itemize @bullet
@item
the @samp{-e} @var{entry} command-line option;
@item
the @code{ENTRY(@var{symbol})} command in a linker script;
@item
the value of the symbol @code{start}, if defined;
@item
the address of the first byte of the @samp{.text} section, if present;
@item
The address @code{0}.
@end itemize

@node File Commands
@subsection Commands dealing with files
@cindex linker script file commands
Several linker script commands deal with files.

@table @code
@item INCLUDE @var{filename}
@kindex INCLUDE @var{filename}
@cindex including a linker script
Include the linker script @var{filename} at this point.  The file will
be searched for in the current directory, and in any directory specified
with the @option{-L} option.  You can nest calls to @code{INCLUDE} up to
10 levels deep.

@item INPUT(@var{file}, @var{file}, @dots{})
@itemx INPUT(@var{file} @var{file} @dots{})
@kindex INPUT(@var{files})
@cindex input files in linker scripts
@cindex input object files in linker scripts
@cindex linker script input object files
The @code{INPUT} command directs the linker to include the named files
in the link, as though they were named on the command line.

For example, if you always want to include @file{subr.o} any time you do
a link, but you can't be bothered to put it on every link command line,
then you can put @samp{INPUT (subr.o)} in your linker script.

In fact, if you like, you can list all of your input files in the linker
script, and then invoke the linker with nothing but a @samp{-T} option.

The linker will first try to open the file in the current directory.  If
it is not found, the linker will search through the archive library
search path.  See the description of @samp{-L} in @ref{Options,,Command
Line Options}.

If you use @samp{INPUT (-l@var{file})}, @command{ld} will transform the
name to @code{lib@var{file}.a}, as with the command line argument
@samp{-l}.

When you use the @code{INPUT} command in an implicit linker script, the
files will be included in the link at the point at which the linker
script file is included.  This can affect archive searching.

@item GROUP(@var{file}, @var{file}, @dots{})
@itemx GROUP(@var{file} @var{file} @dots{})
@kindex GROUP(@var{files})
@cindex grouping input files
The @code{GROUP} command is like @code{INPUT}, except that the named
files should all be archives, and they are searched repeatedly until no
new undefined references are created.  See the description of @samp{-(}
in @ref{Options,,Command Line Options}.

@item OUTPUT(@var{filename})
@kindex OUTPUT(@var{filename})
@cindex output file name in linker scripot
The @code{OUTPUT} command names the output file.  Using
@code{OUTPUT(@var{filename})} in the linker script is exactly like using
@samp{-o @var{filename}} on the command line (@pxref{Options,,Command
Line Options}).  If both are used, the command line option takes
precedence.

You can use the @code{OUTPUT} command to define a default name for the
output file other than the usual default of @file{a.out}.

@item SEARCH_DIR(@var{path})
@kindex SEARCH_DIR(@var{path})
@cindex library search path in linker script
@cindex archive search path in linker script
@cindex search path in linker script
The @code{SEARCH_DIR} command adds @var{path} to the list of paths where
@command{ld} looks for archive libraries.  Using
@code{SEARCH_DIR(@var{path})} is exactly like using @samp{-L @var{path}}
on the command line (@pxref{Options,,Command Line Options}).  If both
are used, then the linker will search both paths.  Paths specified using
the command line option are searched first.

@item STARTUP(@var{filename})
@kindex STARTUP(@var{filename})
@cindex first input file
The @code{STARTUP} command is just like the @code{INPUT} command, except
that @var{filename} will become the first input file to be linked, as
though it were specified first on the command line.  This may be useful
when using a system in which the entry point is always the start of the
first file.
@end table

@ifclear SingleFormat
@node Format Commands
@subsection Commands dealing with object file formats
A couple of linker script commands deal with object file formats.

@table @code
@item OUTPUT_FORMAT(@var{bfdname})
@itemx OUTPUT_FORMAT(@var{default}, @var{big}, @var{little})
@kindex OUTPUT_FORMAT(@var{bfdname})
@cindex output file format in linker script
The @code{OUTPUT_FORMAT} command names the BFD format to use for the
output file (@pxref{BFD}).  Using @code{OUTPUT_FORMAT(@var{bfdname})} is
exactly like using @samp{--oformat @var{bfdname}} on the command line
(@pxref{Options,,Command Line Options}).  If both are used, the command
line option takes precedence.

You can use @code{OUTPUT_FORMAT} with three arguments to use different
formats based on the @samp{-EB} and @samp{-EL} command line options.
This permits the linker script to set the output format based on the
desired endianness.

If neither @samp{-EB} nor @samp{-EL} are used, then the output format
will be the first argument, @var{default}.  If @samp{-EB} is used, the
output format will be the second argument, @var{big}.  If @samp{-EL} is
used, the output format will be the third argument, @var{little}.

For example, the default linker script for the MIPS ELF target uses this
command:
@smallexample
OUTPUT_FORMAT(elf32-bigmips, elf32-bigmips, elf32-littlemips)
@end smallexample
This says that the default format for the output file is
@samp{elf32-bigmips}, but if the user uses the @samp{-EL} command line
option, the output file will be created in the @samp{elf32-littlemips}
format.

@item TARGET(@var{bfdname})
@kindex TARGET(@var{bfdname})
@cindex input file format in linker script
The @code{TARGET} command names the BFD format to use when reading input
files.  It affects subsequent @code{INPUT} and @code{GROUP} commands.
This command is like using @samp{-b @var{bfdname}} on the command line
(@pxref{Options,,Command Line Options}).  If the @code{TARGET} command
is used but @code{OUTPUT_FORMAT} is not, then the last @code{TARGET}
command is also used to set the format for the output file.  @xref{BFD}.
@end table
@end ifclear

@node Miscellaneous Commands
@subsection Other linker script commands
There are a few other linker scripts commands.

@table @code
@item ASSERT(@var{exp}, @var{message})
@kindex ASSERT
@cindex assertion in linker script
Ensure that @var{exp} is non-zero.  If it is zero, then exit the linker
with an error code, and print @var{message}.

@item EXTERN(@var{symbol} @var{symbol} @dots{})
@kindex EXTERN
@cindex undefined symbol in linker script
Force @var{symbol} to be entered in the output file as an undefined
symbol.  Doing this may, for example, trigger linking of additional
modules from standard libraries.  You may list several @var{symbol}s for
each @code{EXTERN}, and you may use @code{EXTERN} multiple times.  This
command has the same effect as the @samp{-u} command-line option.

@item FORCE_COMMON_ALLOCATION
@kindex FORCE_COMMON_ALLOCATION
@cindex common allocation in linker script
This command has the same effect as the @samp{-d} command-line option:
to make @command{ld} assign space to common symbols even if a relocatable
output file is specified (@samp{-r}).

@item INHIBIT_COMMON_ALLOCATION
@kindex INHIBIT_COMMON_ALLOCATION
@cindex common allocation in linker script
This command has the same effect as the @samp{--no-define-common}
command-line option: to make @code{ld} omit the assignment of addresses
to common symbols even for a non-relocatable output file.

@item NOCROSSREFS(@var{section} @var{section} @dots{})
@kindex NOCROSSREFS(@var{sections})
@cindex cross references
This command may be used to tell @command{ld} to issue an error about any
references among certain output sections.

In certain types of programs, particularly on embedded systems when
using overlays, when one section is loaded into memory, another section
will not be.  Any direct references between the two sections would be
errors.  For example, it would be an error if code in one section called
a function defined in the other section.

The @code{NOCROSSREFS} command takes a list of output section names.  If
@command{ld} detects any cross references between the sections, it reports
an error and returns a non-zero exit status.  Note that the
@code{NOCROSSREFS} command uses output section names, not input section
names.

@ifclear SingleFormat
@item OUTPUT_ARCH(@var{bfdarch})
@kindex OUTPUT_ARCH(@var{bfdarch})
@cindex machine architecture
@cindex architecture
Specify a particular output machine architecture.  The argument is one
of the names used by the BFD library (@pxref{BFD}).  You can see the
architecture of an object file by using the @code{objdump} program with
the @samp{-f} option.
@end ifclear
@end table

@node Assignments
@section Assigning Values to Symbols
@cindex assignment in scripts
@cindex symbol definition, scripts
@cindex variables, defining
You may assign a value to a symbol in a linker script.  This will define
the symbol as a global symbol.

@menu
* Simple Assignments::		Simple Assignments
* PROVIDE::			PROVIDE
@end menu

@node Simple Assignments
@subsection Simple Assignments

You may assign to a symbol using any of the C assignment operators:

@table @code
@item @var{symbol} = @var{expression} ;
@itemx @var{symbol} += @var{expression} ;
@itemx @var{symbol} -= @var{expression} ;
@itemx @var{symbol} *= @var{expression} ;
@itemx @var{symbol} /= @var{expression} ;
@itemx @var{symbol} <<= @var{expression} ;
@itemx @var{symbol} >>= @var{expression} ;
@itemx @var{symbol} &= @var{expression} ;
@itemx @var{symbol} |= @var{expression} ;
@end table

The first case will define @var{symbol} to the value of
@var{expression}.  In the other cases, @var{symbol} must already be
defined, and the value will be adjusted accordingly.

The special symbol name @samp{.} indicates the location counter.  You
may only use this within a @code{SECTIONS} command.

The semicolon after @var{expression} is required.

Expressions are defined below; see @ref{Expressions}.

You may write symbol assignments as commands in their own right, or as
statements within a @code{SECTIONS} command, or as part of an output
section description in a @code{SECTIONS} command.

The section of the symbol will be set from the section of the
expression; for more information, see @ref{Expression Section}.

Here is an example showing the three different places that symbol
assignments may be used:

@smallexample
floating_point = 0;
SECTIONS
@{
  .text :
    @{
      *(.text)
      _etext = .;
    @}
  _bdata = (. + 3) & ~ 3;
  .data : @{ *(.data) @}
@}
@end smallexample
@noindent
In this example, the symbol @samp{floating_point} will be defined as
zero.  The symbol @samp{_etext} will be defined as the address following
the last @samp{.text} input section.  The symbol @samp{_bdata} will be
defined as the address following the @samp{.text} output section aligned
upward to a 4 byte boundary.

@node PROVIDE
@subsection PROVIDE
@cindex PROVIDE
In some cases, it is desirable for a linker script to define a symbol
only if it is referenced and is not defined by any object included in
the link.  For example, traditional linkers defined the symbol
@samp{etext}.  However, ANSI C requires that the user be able to use
@samp{etext} as a function name without encountering an error.  The
@code{PROVIDE} keyword may be used to define a symbol, such as
@samp{etext}, only if it is referenced but not defined.  The syntax is
@code{PROVIDE(@var{symbol} = @var{expression})}.

Here is an example of using @code{PROVIDE} to define @samp{etext}:
@smallexample
SECTIONS
@{
  .text :
    @{
      *(.text)
      _etext = .;
      PROVIDE(etext = .);
    @}
@}
@end smallexample

In this example, if the program defines @samp{_etext} (with a leading
underscore), the linker will give a multiple definition error.  If, on
the other hand, the program defines @samp{etext} (with no leading
underscore), the linker will silently use the definition in the program.
If the program references @samp{etext} but does not define it, the
linker will use the definition in the linker script.

@node SECTIONS
@section SECTIONS command
@kindex SECTIONS
The @code{SECTIONS} command tells the linker how to map input sections
into output sections, and how to place the output sections in memory.

The format of the @code{SECTIONS} command is:
@smallexample
SECTIONS
@{
  @var{sections-command}
  @var{sections-command}
  @dots{}
@}
@end smallexample

Each @var{sections-command} may of be one of the following:

@itemize @bullet
@item
an @code{ENTRY} command (@pxref{Entry Point,,Entry command})
@item
a symbol assignment (@pxref{Assignments})
@item
an output section description
@item
an overlay description
@end itemize

The @code{ENTRY} command and symbol assignments are permitted inside the
@code{SECTIONS} command for convenience in using the location counter in
those commands.  This can also make the linker script easier to
understand because you can use those commands at meaningful points in
the layout of the output file.

Output section descriptions and overlay descriptions are described
below.

If you do not use a @code{SECTIONS} command in your linker script, the
linker will place each input section into an identically named output
section in the order that the sections are first encountered in the
input files.  If all input sections are present in the first file, for
example, the order of sections in the output file will match the order
in the first input file.  The first section will be at address zero.

@menu
* Output Section Description::	Output section description
* Output Section Name::		Output section name
* Output Section Address::	Output section address
* Input Section::		Input section description
* Output Section Data::		Output section data
* Output Section Keywords::	Output section keywords
* Output Section Discarding::	Output section discarding
* Output Section Attributes::	Output section attributes
* Overlay Description::		Overlay description
@end menu

@node Output Section Description
@subsection Output section description
The full description of an output section looks like this:
@smallexample
@group
@var{section} [@var{address}] [(@var{type})] : [AT(@var{lma})]
  @{
    @var{output-section-command}
    @var{output-section-command}
    @dots{}
  @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample

Most output sections do not use most of the optional section attributes.

The whitespace around @var{section} is required, so that the section
name is unambiguous.  The colon and the curly braces are also required.
The line breaks and other white space are optional.

Each @var{output-section-command} may be one of the following:

@itemize @bullet
@item
a symbol assignment (@pxref{Assignments})
@item
an input section description (@pxref{Input Section})
@item
data values to include directly (@pxref{Output Section Data})
@item
a special output section keyword (@pxref{Output Section Keywords})
@end itemize

@node Output Section Name
@subsection Output section name
@cindex name, section
@cindex section name
The name of the output section is @var{section}.  @var{section} must
meet the constraints of your output format.  In formats which only
support a limited number of sections, such as @code{a.out}, the name
must be one of the names supported by the format (@code{a.out}, for
example, allows only @samp{.text}, @samp{.data} or @samp{.bss}). If the
output format supports any number of sections, but with numbers and not
names (as is the case for Oasys), the name should be supplied as a
quoted numeric string.  A section name may consist of any sequence of
characters, but a name which contains any unusual characters such as
commas must be quoted.

The output section name @samp{/DISCARD/} is special; @ref{Output Section
Discarding}.

@node Output Section Address
@subsection Output section address
@cindex address, section
@cindex section address
The @var{address} is an expression for the VMA (the virtual memory
address) of the output section.  If you do not provide @var{address},
the linker will set it based on @var{region} if present, or otherwise
based on the current value of the location counter.

If you provide @var{address}, the address of the output section will be
set to precisely that.  If you provide neither @var{address} nor
@var{region}, then the address of the output section will be set to the
current value of the location counter aligned to the alignment
requirements of the output section.  The alignment requirement of the
output section is the strictest alignment of any input section contained
within the output section.

For example,
@smallexample
.text . : @{ *(.text) @}
@end smallexample
@noindent
and
@smallexample
.text : @{ *(.text) @}
@end smallexample
@noindent
are subtly different.  The first will set the address of the
@samp{.text} output section to the current value of the location
counter.  The second will set it to the current value of the location
counter aligned to the strictest alignment of a @samp{.text} input
section.

The @var{address} may be an arbitrary expression; @ref{Expressions}.
For example, if you want to align the section on a 0x10 byte boundary,
so that the lowest four bits of the section address are zero, you could
do something like this:
@smallexample
.text ALIGN(0x10) : @{ *(.text) @}
@end smallexample
@noindent
This works because @code{ALIGN} returns the current location counter
aligned upward to the specified value.

Specifying @var{address} for a section will change the value of the
location counter.

@node Input Section
@subsection Input section description
@cindex input sections
@cindex mapping input sections to output sections
The most common output section command is an input section description.

The input section description is the most basic linker script operation.
You use output sections to tell the linker how to lay out your program
in memory.  You use input section descriptions to tell the linker how to
map the input files into your memory layout.

@menu
* Input Section Basics::	Input section basics
* Input Section Wildcards::	Input section wildcard patterns
* Input Section Common::	Input section for common symbols
* Input Section Keep::		Input section and garbage collection
* Input Section Example::	Input section example
@end menu

@node Input Section Basics
@subsubsection Input section basics
@cindex input section basics
An input section description consists of a file name optionally followed
by a list of section names in parentheses.

The file name and the section name may be wildcard patterns, which we
describe further below (@pxref{Input Section Wildcards}).

The most common input section description is to include all input
sections with a particular name in the output section.  For example, to
include all input @samp{.text} sections, you would write:
@smallexample
*(.text)
@end smallexample
@noindent
Here the @samp{*} is a wildcard which matches any file name.  To exclude a list
of files from matching the file name wildcard, EXCLUDE_FILE may be used to
match all files except the ones specified in the EXCLUDE_FILE list.  For
example:
@smallexample
(*(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors))
@end smallexample
will cause all .ctors sections from all files except @file{crtend.o} and
@file{otherfile.o} to be included.

There are two ways to include more than one section:
@smallexample
*(.text .rdata)
*(.text) *(.rdata)
@end smallexample
@noindent
The difference between these is the order in which the @samp{.text} and
@samp{.rdata} input sections will appear in the output section.  In the
first example, they will be intermingled, appearing in the same order as
they are found in the linker input.  In the second example, all
@samp{.text} input sections will appear first, followed by all
@samp{.rdata} input sections.

You can specify a file name to include sections from a particular file.
You would do this if one or more of your files contain special data that
needs to be at a particular location in memory.  For example:
@smallexample
data.o(.data)
@end smallexample

If you use a file name without a list of sections, then all sections in
the input file will be included in the output section.  This is not
commonly done, but it may by useful on occasion.  For example:
@smallexample
data.o
@end smallexample

When you use a file name which does not contain any wild card
characters, the linker will first see if you also specified the file
name on the linker command line or in an @code{INPUT} command.  If you
did not, the linker will attempt to open the file as an input file, as
though it appeared on the command line.  Note that this differs from an
@code{INPUT} command, because the linker will not search for the file in
the archive search path.

@node Input Section Wildcards
@subsubsection Input section wildcard patterns
@cindex input section wildcards
@cindex wildcard file name patterns
@cindex file name wildcard patterns
@cindex section name wildcard patterns
In an input section description, either the file name or the section
name or both may be wildcard patterns.

The file name of @samp{*} seen in many examples is a simple wildcard
pattern for the file name.

The wildcard patterns are like those used by the Unix shell.

@table @samp
@item *
matches any number of characters
@item ?
matches any single character
@item [@var{chars}]
matches a single instance of any of the @var{chars}; the @samp{-}
character may be used to specify a range of characters, as in
@samp{[a-z]} to match any lower case letter
@item \
quotes the following character
@end table

When a file name is matched with a wildcard, the wildcard characters
will not match a @samp{/} character (used to separate directory names on
Unix).  A pattern consisting of a single @samp{*} character is an
exception; it will always match any file name, whether it contains a
@samp{/} or not.  In a section name, the wildcard characters will match
a @samp{/} character.

File name wildcard patterns only match files which are explicitly
specified on the command line or in an @code{INPUT} command.  The linker
does not search directories to expand wildcards.

If a file name matches more than one wildcard pattern, or if a file name
appears explicitly and is also matched by a wildcard pattern, the linker
will use the first match in the linker script.  For example, this
sequence of input section descriptions is probably in error, because the
@file{data.o} rule will not be used:
@smallexample
.data : @{ *(.data) @}
.data1 : @{ data.o(.data) @}
@end smallexample

@cindex SORT
Normally, the linker will place files and sections matched by wildcards
in the order in which they are seen during the link.  You can change
this by using the @code{SORT} keyword, which appears before a wildcard
pattern in parentheses (e.g., @code{SORT(.text*)}).  When the
@code{SORT} keyword is used, the linker will sort the files or sections
into ascending order by name before placing them in the output file.

If you ever get confused about where input sections are going, use the
@samp{-M} linker option to generate a map file.  The map file shows
precisely how input sections are mapped to output sections.

This example shows how wildcard patterns might be used to partition
files.  This linker script directs the linker to place all @samp{.text}
sections in @samp{.text} and all @samp{.bss} sections in @samp{.bss}.
The linker will place the @samp{.data} section from all files beginning
with an upper case character in @samp{.DATA}; for all other files, the
linker will place the @samp{.data} section in @samp{.data}.
@smallexample
@group
SECTIONS @{
  .text : @{ *(.text) @}
  .DATA : @{ [A-Z]*(.data) @}
  .data : @{ *(.data) @}
  .bss : @{ *(.bss) @}
@}
@end group
@end smallexample

@node Input Section Common
@subsubsection Input section for common symbols
@cindex common symbol placement
@cindex uninitialized data placement
A special notation is needed for common symbols, because in many object
file formats common symbols do not have a particular input section.  The
linker treats common symbols as though they are in an input section
named @samp{COMMON}.

You may use file names with the @samp{COMMON} section just as with any
other input sections.  You can use this to place common symbols from a
particular input file in one section while common symbols from other
input files are placed in another section.

In most cases, common symbols in input files will be placed in the
@samp{.bss} section in the output file.  For example:
@smallexample
.bss @{ *(.bss) *(COMMON) @}
@end smallexample

@cindex scommon section
@cindex small common symbols
Some object file formats have more than one type of common symbol.  For
example, the MIPS ELF object file format distinguishes standard common
symbols and small common symbols.  In this case, the linker will use a
different special section name for other types of common symbols.  In
the case of MIPS ELF, the linker uses @samp{COMMON} for standard common
symbols and @samp{.scommon} for small common symbols.  This permits you
to map the different types of common symbols into memory at different
locations.

@cindex [COMMON]
You will sometimes see @samp{[COMMON]} in old linker scripts.  This
notation is now considered obsolete.  It is equivalent to
@samp{*(COMMON)}.

@node Input Section Keep
@subsubsection Input section and garbage collection
@cindex KEEP
@cindex garbage collection
When link-time garbage collection is in use (@samp{--gc-sections}),
it is often useful to mark sections that should not be eliminated.
This is accomplished by surrounding an input section's wildcard entry
with @code{KEEP()}, as in @code{KEEP(*(.init))} or
@code{KEEP(SORT(*)(.ctors))}.

@node Input Section Example
@subsubsection Input section example
The following example is a complete linker script.  It tells the linker
to read all of the sections from file @file{all.o} and place them at the
start of output section @samp{outputa} which starts at location
@samp{0x10000}.  All of section @samp{.input1} from file @file{foo.o}
follows immediately, in the same output section.  All of section
@samp{.input2} from @file{foo.o} goes into output section
@samp{outputb}, followed by section @samp{.input1} from @file{foo1.o}.
All of the remaining @samp{.input1} and @samp{.input2} sections from any
files are written to output section @samp{outputc}.

@smallexample
@group
SECTIONS @{
  outputa 0x10000 :
    @{
    all.o
    foo.o (.input1)
    @}
  outputb :
    @{
    foo.o (.input2)
    foo1.o (.input1)
    @}
  outputc :
    @{
    *(.input1)
    *(.input2)
    @}
@}
@end group
@end smallexample

@node Output Section Data
@subsection Output section data
@cindex data
@cindex section data
@cindex output section data
@kindex BYTE(@var{expression})
@kindex SHORT(@var{expression})
@kindex LONG(@var{expression})
@kindex QUAD(@var{expression})
@kindex SQUAD(@var{expression})
You can include explicit bytes of data in an output section by using
@code{BYTE}, @code{SHORT}, @code{LONG}, @code{QUAD}, or @code{SQUAD} as
an output section command.  Each keyword is followed by an expression in
parentheses providing the value to store (@pxref{Expressions}).  The
value of the expression is stored at the current value of the location
counter.

The @code{BYTE}, @code{SHORT}, @code{LONG}, and @code{QUAD} commands
store one, two, four, and eight bytes (respectively).  After storing the
bytes, the location counter is incremented by the number of bytes
stored.

For example, this will store the byte 1 followed by the four byte value
of the symbol @samp{addr}:
@smallexample
BYTE(1)
LONG(addr)
@end smallexample

When using a 64 bit host or target, @code{QUAD} and @code{SQUAD} are the
same; they both store an 8 byte, or 64 bit, value.  When both host and
target are 32 bits, an expression is computed as 32 bits.  In this case
@code{QUAD} stores a 32 bit value zero extended to 64 bits, and
@code{SQUAD} stores a 32 bit value sign extended to 64 bits.

If the object file format of the output file has an explicit endianness,
which is the normal case, the value will be stored in that endianness.
When the object file format does not have an explicit endianness, as is
true of, for example, S-records, the value will be stored in the
endianness of the first input object file.

Note - these commands only work inside a section description and not
between them, so the following will produce an error from the linker:
@smallexample
SECTIONS @{@ .text : @{@ *(.text) @}@ LONG(1) .data : @{@ *(.data) @}@ @}@
@end smallexample
whereas this will work:
@smallexample
SECTIONS @{@ .text : @{@ *(.text) ; LONG(1) @}@ .data : @{@ *(.data) @}@ @}@
@end smallexample

@kindex FILL(@var{expression})
@cindex holes, filling
@cindex unspecified memory
You may use the @code{FILL} command to set the fill pattern for the
current section.  It is followed by an expression in parentheses.  Any
otherwise unspecified regions of memory within the section (for example,
gaps left due to the required alignment of input sections) are filled
with the value of the expression, repeated as
necessary.  A @code{FILL} statement covers memory locations after the
point at which it occurs in the section definition; by including more
than one @code{FILL} statement, you can have different fill patterns in
different parts of an output section.

This example shows how to fill unspecified regions of memory with the
value @samp{0x90}:
@smallexample
FILL(0x90909090)
@end smallexample

The @code{FILL} command is similar to the @samp{=@var{fillexp}} output
section attribute, but it only affects the
part of the section following the @code{FILL} command, rather than the
entire section.  If both are used, the @code{FILL} command takes
precedence.  @xref{Output Section Fill}, for details on the fill
expression.

@node Output Section Keywords
@subsection Output section keywords
There are a couple of keywords which can appear as output section
commands.

@table @code
@kindex CREATE_OBJECT_SYMBOLS
@cindex input filename symbols
@cindex filename symbols
@item CREATE_OBJECT_SYMBOLS
The command tells the linker to create a symbol for each input file.
The name of each symbol will be the name of the corresponding input
file.  The section of each symbol will be the output section in which
the @code{CREATE_OBJECT_SYMBOLS} command appears.

This is conventional for the a.out object file format.  It is not
normally used for any other object file format.

@kindex CONSTRUCTORS
@cindex C++ constructors, arranging in link
@cindex constructors, arranging in link
@item CONSTRUCTORS
When linking using the a.out object file format, the linker uses an
unusual set construct to support C++ global constructors and
destructors.  When linking object file formats which do not support
arbitrary sections, such as ECOFF and XCOFF, the linker will
automatically recognize C++ global constructors and destructors by name.
For these object file formats, the @code{CONSTRUCTORS} command tells the
linker to place constructor information in the output section where the
@code{CONSTRUCTORS} command appears.  The @code{CONSTRUCTORS} command is
ignored for other object file formats.

The symbol @w{@code{__CTOR_LIST__}} marks the start of the global
constructors, and the symbol @w{@code{__DTOR_LIST}} marks the end.  The
first word in the list is the number of entries, followed by the address
of each constructor or destructor, followed by a zero word.  The
compiler must arrange to actually run the code.  For these object file
formats @sc{gnu} C++ normally calls constructors from a subroutine
@code{__main}; a call to @code{__main} is automatically inserted into
the startup code for @code{main}.  @sc{gnu} C++ normally runs
destructors either by using @code{atexit}, or directly from the function
@code{exit}.

For object file formats such as @code{COFF} or @code{ELF} which support
arbitrary section names, @sc{gnu} C++ will normally arrange to put the
addresses of global constructors and destructors into the @code{.ctors}
and @code{.dtors} sections.  Placing the following sequence into your
linker script will build the sort of table which the @sc{gnu} C++
runtime code expects to see.

@smallexample
      __CTOR_LIST__ = .;
      LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
      *(.ctors)
      LONG(0)
      __CTOR_END__ = .;
      __DTOR_LIST__ = .;
      LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2)
      *(.dtors)
      LONG(0)
      __DTOR_END__ = .;
@end smallexample

If you are using the @sc{gnu} C++ support for initialization priority,
which provides some control over the order in which global constructors
are run, you must sort the constructors at link time to ensure that they
are executed in the correct order.  When using the @code{CONSTRUCTORS}
command, use @samp{SORT(CONSTRUCTORS)} instead.  When using the
@code{.ctors} and @code{.dtors} sections, use @samp{*(SORT(.ctors))} and
@samp{*(SORT(.dtors))} instead of just @samp{*(.ctors)} and
@samp{*(.dtors)}.

Normally the compiler and linker will handle these issues automatically,
and you will not need to concern yourself with them.  However, you may
need to consider this if you are using C++ and writing your own linker
scripts.

@end table

@node Output Section Discarding
@subsection Output section discarding
@cindex discarding sections
@cindex sections, discarding
@cindex removing sections
The linker will not create output section which do not have any
contents.  This is for convenience when referring to input sections that
may or may not be present in any of the input files.  For example:
@smallexample
.foo @{ *(.foo) @}
@end smallexample
@noindent
will only create a @samp{.foo} section in the output file if there is a
@samp{.foo} section in at least one input file.

If you use anything other than an input section description as an output
section command, such as a symbol assignment, then the output section
will always be created, even if there are no matching input sections.

@cindex /DISCARD/
The special output section name @samp{/DISCARD/} may be used to discard
input sections.  Any input sections which are assigned to an output
section named @samp{/DISCARD/} are not included in the output file.

@node Output Section Attributes
@subsection Output section attributes
@cindex output section attributes
We showed above that the full description of an output section looked
like this:
@smallexample
@group
@var{section} [@var{address}] [(@var{type})] : [AT(@var{lma})]
  @{
    @var{output-section-command}
    @var{output-section-command}
    @dots{}
  @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample
We've already described @var{section}, @var{address}, and
@var{output-section-command}.  In this section we will describe the
remaining section attributes.

@menu
* Output Section Type::		Output section type
* Output Section LMA::		Output section LMA
* Output Section Region::	Output section region
* Output Section Phdr::		Output section phdr
* Output Section Fill::		Output section fill
@end menu

@node Output Section Type
@subsubsection Output section type
Each output section may have a type.  The type is a keyword in
parentheses.  The following types are defined:

@table @code
@item NOLOAD
The section should be marked as not loadable, so that it will not be
loaded into memory when the program is run.
@item DSECT
@itemx COPY
@itemx INFO
@itemx OVERLAY
These type names are supported for backward compatibility, and are
rarely used.  They all have the same effect: the section should be
marked as not allocatable, so that no memory is allocated for the
section when the program is run.
@end table

@kindex NOLOAD
@cindex prevent unnecessary loading
@cindex loading, preventing
The linker normally sets the attributes of an output section based on
the input sections which map into it.  You can override this by using
the section type.  For example, in the script sample below, the
@samp{ROM} section is addressed at memory location @samp{0} and does not
need to be loaded when the program is run.  The contents of the
@samp{ROM} section will appear in the linker output file as usual.
@smallexample
@group
SECTIONS @{
  ROM 0 (NOLOAD) : @{ @dots{} @}
  @dots{}
@}
@end group
@end smallexample

@node Output Section LMA
@subsubsection Output section LMA
@kindex AT>@var{lma_region}
@kindex AT(@var{lma})
@cindex load address
@cindex section load address
Every section has a virtual address (VMA) and a load address (LMA); see
@ref{Basic Script Concepts}.  The address expression which may appear in
an output section description sets the VMA (@pxref{Output Section
Address}).

The linker will normally set the LMA equal to the VMA.  You can change
that by using the @code{AT} keyword.  The expression @var{lma} that
follows the @code{AT} keyword specifies the load address of the
section.  Alternatively, with @samp{AT>@var{lma_region}} expression,
you may specify a memory region for the section's load address. @xref{MEMORY}.

@cindex ROM initialized data
@cindex initialized data in ROM
This feature is designed to make it easy to build a ROM image.  For
example, the following linker script creates three output sections: one
called @samp{.text}, which starts at @code{0x1000}, one called
@samp{.mdata}, which is loaded at the end of the @samp{.text} section
even though its VMA is @code{0x2000}, and one called @samp{.bss} to hold
uninitialized data at address @code{0x3000}.  The symbol @code{_data} is
defined with the value @code{0x2000}, which shows that the location
counter holds the VMA value, not the LMA value.

@smallexample
@group
SECTIONS
  @{
  .text 0x1000 : @{ *(.text) _etext = . ; @}
  .mdata 0x2000 :
    AT ( ADDR (.text) + SIZEOF (.text) )
    @{ _data = . ; *(.data); _edata = . ;  @}
  .bss 0x3000 :
    @{ _bstart = . ;  *(.bss) *(COMMON) ; _bend = . ;@}
@}
@end group
@end smallexample

The run-time initialization code for use with a program generated with
this linker script would include something like the following, to copy
the initialized data from the ROM image to its runtime address.  Notice
how this code takes advantage of the symbols defined by the linker
script.

@smallexample
@group
extern char _etext, _data, _edata, _bstart, _bend;
char *src = &_etext;
char *dst = &_data;

/* ROM has data at end of text; copy it. */
while (dst < &_edata) @{
  *dst++ = *src++;
@}

/* Zero bss */
for (dst = &_bstart; dst< &_bend; dst++)
  *dst = 0;
@end group
@end smallexample

@node Output Section Region
@subsubsection Output section region
@kindex >@var{region}
@cindex section, assigning to memory region
@cindex memory regions and sections
You can assign a section to a previously defined region of memory by
using @samp{>@var{region}}.  @xref{MEMORY}.

Here is a simple example:
@smallexample
@group
MEMORY @{ rom : ORIGIN = 0x1000, LENGTH = 0x1000 @}
SECTIONS @{ ROM : @{ *(.text) @} >rom @}
@end group
@end smallexample

@node Output Section Phdr
@subsubsection Output section phdr
@kindex :@var{phdr}
@cindex section, assigning to program header
@cindex program headers and sections
You can assign a section to a previously defined program segment by
using @samp{:@var{phdr}}.  @xref{PHDRS}.  If a section is assigned to
one or more segments, then all subsequent allocated sections will be
assigned to those segments as well, unless they use an explicitly
@code{:@var{phdr}} modifier.  You can use @code{:NONE} to tell the
linker to not put the section in any segment at all.

Here is a simple example:
@smallexample
@group
PHDRS @{ text PT_LOAD ; @}
SECTIONS @{ .text : @{ *(.text) @} :text @}
@end group
@end smallexample

@node Output Section Fill
@subsubsection Output section fill
@kindex =@var{fillexp}
@cindex section fill pattern
@cindex fill pattern, entire section
You can set the fill pattern for an entire section by using
@samp{=@var{fillexp}}.  @var{fillexp} is an expression
(@pxref{Expressions}).  Any otherwise unspecified regions of memory
within the output section (for example, gaps left due to the required
alignment of input sections) will be filled with the value, repeated as
necessary.  If the fill expression is a simple hex number, ie. a string
of hex digit starting with @samp{0x} and without a trailing @samp{k} or @samp{M}, then
an arbitrarily long sequence of hex digits can be used to specify the
fill pattern;  Leading zeros become part of the pattern too.  For all
other cases, including extra parentheses or a unary @code{+}, the fill
pattern is the four least significant bytes of the value of the
expression.  In all cases, the number is big-endian.

You can also change the fill value with a @code{FILL} command in the
output section commands; (@pxref{Output Section Data}).

Here is a simple example:
@smallexample
@group
SECTIONS @{ .text : @{ *(.text) @} =0x90909090 @}
@end group
@end smallexample

@node Overlay Description
@subsection Overlay description
@kindex OVERLAY
@cindex overlays
An overlay description provides an easy way to describe sections which
are to be loaded as part of a single memory image but are to be run at
the same memory address.  At run time, some sort of overlay manager will
copy the overlaid sections in and out of the runtime memory address as
required, perhaps by simply manipulating addressing bits.  This approach
can be useful, for example, when a certain region of memory is faster
than another.

Overlays are described using the @code{OVERLAY} command.  The
@code{OVERLAY} command is used within a @code{SECTIONS} command, like an
output section description.  The full syntax of the @code{OVERLAY}
command is as follows:
@smallexample
@group
OVERLAY [@var{start}] : [NOCROSSREFS] [AT ( @var{ldaddr} )]
  @{
    @var{secname1}
      @{
        @var{output-section-command}
        @var{output-section-command}
        @dots{}
      @} [:@var{phdr}@dots{}] [=@var{fill}]
    @var{secname2}
      @{
        @var{output-section-command}
        @var{output-section-command}
        @dots{}
      @} [:@var{phdr}@dots{}] [=@var{fill}]
    @dots{}
  @} [>@var{region}] [:@var{phdr}@dots{}] [=@var{fill}]
@end group
@end smallexample

Everything is optional except @code{OVERLAY} (a keyword), and each
section must have a name (@var{secname1} and @var{secname2} above).  The
section definitions within the @code{OVERLAY} construct are identical to
those within the general @code{SECTIONS} contruct (@pxref{SECTIONS}),
except that no addresses and no memory regions may be defined for
sections within an @code{OVERLAY}.

The sections are all defined with the same starting address.  The load
addresses of the sections are arranged such that they are consecutive in
memory starting at the load address used for the @code{OVERLAY} as a
whole (as with normal section definitions, the load address is optional,
and defaults to the start address; the start address is also optional,
and defaults to the current value of the location counter).

If the @code{NOCROSSREFS} keyword is used, and there any references
among the sections, the linker will report an error.  Since the sections
all run at the same address, it normally does not make sense for one
section to refer directly to another.  @xref{Miscellaneous Commands,
NOCROSSREFS}.

For each section within the @code{OVERLAY}, the linker automatically
defines two symbols.  The symbol @code{__load_start_@var{secname}} is
defined as the starting load address of the section.  The symbol
@code{__load_stop_@var{secname}} is defined as the final load address of
the section.  Any characters within @var{secname} which are not legal
within C identifiers are removed.  C (or assembler) code may use these
symbols to move the overlaid sections around as necessary.

At the end of the overlay, the value of the location counter is set to
the start address of the overlay plus the size of the largest section.

Here is an example.  Remember that this would appear inside a
@code{SECTIONS} construct.
@smallexample
@group
  OVERLAY 0x1000 : AT (0x4000)
   @{
     .text0 @{ o1/*.o(.text) @}
     .text1 @{ o2/*.o(.text) @}
   @}
@end group
@end smallexample
@noindent
This will define both @samp{.text0} and @samp{.text1} to start at
address 0x1000.  @samp{.text0} will be loaded at address 0x4000, and
@samp{.text1} will be loaded immediately after @samp{.text0}.  The
following symbols will be defined: @code{__load_start_text0},
@code{__load_stop_text0}, @code{__load_start_text1},
@code{__load_stop_text1}.

C code to copy overlay @code{.text1} into the overlay area might look
like the following.

@smallexample
@group
  extern char __load_start_text1, __load_stop_text1;
  memcpy ((char *) 0x1000, &__load_start_text1,
          &__load_stop_text1 - &__load_start_text1);
@end group
@end smallexample

Note that the @code{OVERLAY} command is just syntactic sugar, since
everything it does can be done using the more basic commands.  The above
example could have been written identically as follows.

@smallexample
@group
  .text0 0x1000 : AT (0x4000) @{ o1/*.o(.text) @}
  __load_start_text0 = LOADADDR (.text0);
  __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
  .text1 0x1000 : AT (0x4000 + SIZEOF (.text0)) @{ o2/*.o(.text) @}
  __load_start_text1 = LOADADDR (.text1);
  __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
  . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));
@end group
@end smallexample

@node MEMORY
@section MEMORY command
@kindex MEMORY
@cindex memory regions
@cindex regions of memory
@cindex allocating memory
@cindex discontinuous memory
The linker's default configuration permits allocation of all available
memory.  You can override this by using the @code{MEMORY} command.

The @code{MEMORY} command describes the location and size of blocks of
memory in the target.  You can use it to describe which memory regions
may be used by the linker, and which memory regions it must avoid.  You
can then assign sections to particular memory regions.  The linker will
set section addresses based on the memory regions, and will warn about
regions that become too full.  The linker will not shuffle sections
around to fit into the available regions.

A linker script may contain at most one use of the @code{MEMORY}
command.  However, you can define as many blocks of memory within it as
you wish.  The syntax is:
@smallexample
@group
MEMORY
  @{
    @var{name} [(@var{attr})] : ORIGIN = @var{origin}, LENGTH = @var{len}
    @dots{}
  @}
@end group
@end smallexample

The @var{name} is a name used in the linker script to refer to the
region.  The region name has no meaning outside of the linker script.
Region names are stored in a separate name space, and will not conflict
with symbol names, file names, or section names.  Each memory region
must have a distinct name.

@cindex memory region attributes
The @var{attr} string is an optional list of attributes that specify
whether to use a particular memory region for an input section which is
not explicitly mapped in the linker script.  As described in
@ref{SECTIONS}, if you do not specify an output section for some input
section, the linker will create an output section with the same name as
the input section.  If you define region attributes, the linker will use
them to select the memory region for the output section that it creates.

The @var{attr} string must consist only of the following characters:
@table @samp
@item R
Read-only section
@item W
Read/write section
@item X
Executable section
@item A
Allocatable section
@item I
Initialized section
@item L
Same as @samp{I}
@item !
Invert the sense of any of the preceding attributes
@end table

If a unmapped section matches any of the listed attributes other than
@samp{!}, it will be placed in the memory region.  The @samp{!}
attribute reverses this test, so that an unmapped section will be placed
in the memory region only if it does not match any of the listed
attributes.

@kindex ORIGIN =
@kindex o =
@kindex org =
The @var{origin} is an expression for the start address of the memory
region.  The expression must evaluate to a constant before memory
allocation is performed, which means that you may not use any section
relative symbols.  The keyword @code{ORIGIN} may be abbreviated to
@code{org} or @code{o} (but not, for example, @code{ORG}).

@kindex LENGTH =
@kindex len =
@kindex l =
The @var{len} is an expression for the size in bytes of the memory
region.  As with the @var{origin} expression, the expression must
evaluate to a constant before memory allocation is performed.  The
keyword @code{LENGTH} may be abbreviated to @code{len} or @code{l}.

In the following example, we specify that there are two memory regions
available for allocation: one starting at @samp{0} for 256 kilobytes,
and the other starting at @samp{0x40000000} for four megabytes.  The
linker will place into the @samp{rom} memory region every section which
is not explicitly mapped into a memory region, and is either read-only
or executable.  The linker will place other sections which are not
explicitly mapped into a memory region into the @samp{ram} memory
region.

@smallexample
@group
MEMORY
  @{
    rom (rx)  : ORIGIN = 0, LENGTH = 256K
    ram (!rx) : org = 0x40000000, l = 4M
  @}
@end group
@end smallexample

Once you define a memory region, you can direct the linker to place
specific output sections into that memory region by using the
@samp{>@var{region}} output section attribute.  For example, if you have
a memory region named @samp{mem}, you would use @samp{>mem} in the
output section definition.  @xref{Output Section Region}.  If no address
was specified for the output section, the linker will set the address to
the next available address within the memory region.  If the combined
output sections directed to a memory region are too large for the
region, the linker will issue an error message.

@node PHDRS
@section PHDRS Command
@kindex PHDRS
@cindex program headers
@cindex ELF program headers
@cindex program segments
@cindex segments, ELF
The ELF object file format uses @dfn{program headers}, also knows as
@dfn{segments}.  The program headers describe how the program should be
loaded into memory.  You can print them out by using the @code{objdump}
program with the @samp{-p} option.

When you run an ELF program on a native ELF system, the system loader
reads the program headers in order to figure out how to load the
program.  This will only work if the program headers are set correctly.
This manual does not describe the details of how the system loader
interprets program headers; for more information, see the ELF ABI.

The linker will create reasonable program headers by default.  However,
in some cases, you may need to specify the program headers more
precisely.  You may use the @code{PHDRS} command for this purpose.  When
the linker sees the @code{PHDRS} command in the linker script, it will
not create any program headers other than the ones specified.

The linker only pays attention to the @code{PHDRS} command when
generating an ELF output file.  In other cases, the linker will simply
ignore @code{PHDRS}.

This is the syntax of the @code{PHDRS} command.  The words @code{PHDRS},
@code{FILEHDR}, @code{AT}, and @code{FLAGS} are keywords.

@smallexample
@group
PHDRS
@{
  @var{name} @var{type} [ FILEHDR ] [ PHDRS ] [ AT ( @var{address} ) ]
        [ FLAGS ( @var{flags} ) ] ;
@}
@end group
@end smallexample

The @var{name} is used only for reference in the @code{SECTIONS} command
of the linker script.  It is not put into the output file.  Program
header names are stored in a separate name space, and will not conflict
with symbol names, file names, or section names.  Each program header
must have a distinct name.

Certain program header types describe segments of memory which the
system loader will load from the file.  In the linker script, you
specify the contents of these segments by placing allocatable output
sections in the segments.  You use the @samp{:@var{phdr}} output section
attribute to place a section in a particular segment.  @xref{Output
Section Phdr}.

It is normal to put certain sections in more than one segment.  This
merely implies that one segment of memory contains another.  You may
repeat @samp{:@var{phdr}}, using it once for each segment which should
contain the section.

If you place a section in one or more segments using @samp{:@var{phdr}},
then the linker will place all subsequent allocatable sections which do
not specify @samp{:@var{phdr}} in the same segments.  This is for
convenience, since generally a whole set of contiguous sections will be
placed in a single segment.  You can use @code{:NONE} to override the
default segment and tell the linker to not put the section in any
segment at all.

@kindex FILEHDR
@kindex PHDRS
You may use the @code{FILEHDR} and @code{PHDRS} keywords appear after
the program header type to further describe the contents of the segment.
The @code{FILEHDR} keyword means that the segment should include the ELF
file header.  The @code{PHDRS} keyword means that the segment should
include the ELF program headers themselves.

The @var{type} may be one of the following.  The numbers indicate the
value of the keyword.

@table @asis
@item @code{PT_NULL} (0)
Indicates an unused program header.

@item @code{PT_LOAD} (1)
Indicates that this program header describes a segment to be loaded from
the file.

@item @code{PT_DYNAMIC} (2)
Indicates a segment where dynamic linking information can be found.

@item @code{PT_INTERP} (3)
Indicates a segment where the name of the program interpreter may be
found.

@item @code{PT_NOTE} (4)
Indicates a segment holding note information.

@item @code{PT_SHLIB} (5)
A reserved program header type, defined but not specified by the ELF
ABI.

@item @code{PT_PHDR} (6)
Indicates a segment where the program headers may be found.

@item @var{expression}
An expression giving the numeric type of the program header.  This may
be used for types not defined above.
@end table

You can specify that a segment should be loaded at a particular address
in memory by using an @code{AT} expression.  This is identical to the
@code{AT} command used as an output section attribute (@pxref{Output
Section LMA}).  The @code{AT} command for a program header overrides the
output section attribute.

The linker will normally set the segment flags based on the sections
which comprise the segment.  You may use the @code{FLAGS} keyword to
explicitly specify the segment flags.  The value of @var{flags} must be
an integer.  It is used to set the @code{p_flags} field of the program
header.

Here is an example of @code{PHDRS}.  This shows a typical set of program
headers used on a native ELF system.

@example
@group
PHDRS
@{
  headers PT_PHDR PHDRS ;
  interp PT_INTERP ;
  text PT_LOAD FILEHDR PHDRS ;
  data PT_LOAD ;
  dynamic PT_DYNAMIC ;
@}

SECTIONS
@{
  . = SIZEOF_HEADERS;
  .interp : @{ *(.interp) @} :text :interp
  .text : @{ *(.text) @} :text
  .rodata : @{ *(.rodata) @} /* defaults to :text */
  @dots{}
  . = . + 0x1000; /* move to a new page in memory */
  .data : @{ *(.data) @} :data
  .dynamic : @{ *(.dynamic) @} :data :dynamic
  @dots{}
@}
@end group
@end example

@node VERSION
@section VERSION Command
@kindex VERSION @{script text@}
@cindex symbol versions
@cindex version script
@cindex versions of symbols
The linker supports symbol versions when using ELF.  Symbol versions are
only useful when using shared libraries.  The dynamic linker can use
symbol versions to select a specific version of a function when it runs
a program that may have been linked against an earlier version of the
shared library.

You can include a version script directly in the main linker script, or
you can supply the version script as an implicit linker script.  You can
also use the @samp{--version-script} linker option.

The syntax of the @code{VERSION} command is simply
@smallexample
VERSION @{ version-script-commands @}
@end smallexample

The format of the version script commands is identical to that used by
Sun's linker in Solaris 2.5.  The version script defines a tree of
version nodes.  You specify the node names and interdependencies in the
version script.  You can specify which symbols are bound to which
version nodes, and you can reduce a specified set of symbols to local
scope so that they are not globally visible outside of the shared
library.

The easiest way to demonstrate the version script language is with a few
examples.

@smallexample
VERS_1.1 @{
	 global:
		 foo1;
	 local:
		 old*;
		 original*;
		 new*;
@};

VERS_1.2 @{
		 foo2;
@} VERS_1.1;

VERS_2.0 @{
		 bar1; bar2;
@} VERS_1.2;
@end smallexample

This example version script defines three version nodes.  The first
version node defined is @samp{VERS_1.1}; it has no other dependencies.
The script binds the symbol @samp{foo1} to @samp{VERS_1.1}.  It reduces
a number of symbols to local scope so that they are not visible outside
of the shared library; this is done using wildcard patterns, so that any
symbol whose name begins with @samp{old}, @samp{original}, or @samp{new}
is matched.  The wildcard patterns available are the same as those used
in the shell when matching filenames (also known as ``globbing'').

Next, the version script defines node @samp{VERS_1.2}.  This node
depends upon @samp{VERS_1.1}.  The script binds the symbol @samp{foo2}
to the version node @samp{VERS_1.2}.

Finally, the version script defines node @samp{VERS_2.0}.  This node
depends upon @samp{VERS_1.2}.  The scripts binds the symbols @samp{bar1}
and @samp{bar2} are bound to the version node @samp{VERS_2.0}.

When the linker finds a symbol defined in a library which is not
specifically bound to a version node, it will effectively bind it to an
unspecified base version of the library.  You can bind all otherwise
unspecified symbols to a given version node by using @samp{global: *}
somewhere in the version script.

The names of the version nodes have no specific meaning other than what
they might suggest to the person reading them.  The @samp{2.0} version
could just as well have appeared in between @samp{1.1} and @samp{1.2}.
However, this would be a confusing way to write a version script.

Node name can be omited, provided it is the only version node
in the version script.  Such version script doesn't assign any versions to
symbols, only selects which symbols will be globally visible out and which
won't.

@smallexample
@{ global: foo; bar; local: *; @}
@end smallexample

When you link an application against a shared library that has versioned
symbols, the application itself knows which version of each symbol it
requires, and it also knows which version nodes it needs from each
shared library it is linked against.  Thus at runtime, the dynamic
loader can make a quick check to make sure that the libraries you have
linked against do in fact supply all of the version nodes that the
application will need to resolve all of the dynamic symbols.  In this
way it is possible for the dynamic linker to know with certainty that
all external symbols that it needs will be resolvable without having to
search for each symbol reference.

The symbol versioning is in effect a much more sophisticated way of
doing minor version checking that SunOS does.  The fundamental problem
that is being addressed here is that typically references to external
functions are bound on an as-needed basis, and are not all bound when
the application starts up.  If a shared library is out of date, a
required interface may be missing; when the application tries to use
that interface, it may suddenly and unexpectedly fail.  With symbol
versioning, the user will get a warning when they start their program if
the libraries being used with the application are too old.

There are several GNU extensions to Sun's versioning approach.  The
first of these is the ability to bind a symbol to a version node in the
source file where the symbol is defined instead of in the versioning
script.  This was done mainly to reduce the burden on the library
maintainer.  You can do this by putting something like:
@smallexample
__asm__(".symver original_foo,foo@@VERS_1.1");
@end smallexample
@noindent
in the C source file.  This renames the function @samp{original_foo} to
be an alias for @samp{foo} bound to the version node @samp{VERS_1.1}.
The @samp{local:} directive can be used to prevent the symbol
@samp{original_foo} from being exported.

The second GNU extension is to allow multiple versions of the same
function to appear in a given shared library.  In this way you can make
an incompatible change to an interface without increasing the major
version number of the shared library, while still allowing applications
linked against the old interface to continue to function.

To do this, you must use multiple @samp{.symver} directives in the
source file.  Here is an example:

@smallexample
__asm__(".symver original_foo,foo@@");
__asm__(".symver old_foo,foo@@VERS_1.1");
__asm__(".symver old_foo1,foo@@VERS_1.2");
__asm__(".symver new_foo,foo@@@@VERS_2.0");
@end smallexample

In this example, @samp{foo@@} represents the symbol @samp{foo} bound to the
unspecified base version of the symbol.  The source file that contains this
example would define 4 C functions: @samp{original_foo}, @samp{old_foo},
@samp{old_foo1}, and @samp{new_foo}.

When you have multiple definitions of a given symbol, there needs to be
some way to specify a default version to which external references to
this symbol will be bound.  You can do this with the
@samp{foo@@@@VERS_2.0} type of @samp{.symver} directive.  You can only
declare one version of a symbol as the default in this manner; otherwise
you would effectively have multiple definitions of the same symbol.

If you wish to bind a reference to a specific version of the symbol
within the shared library, you can use the aliases of convenience
(i.e. @samp{old_foo}), or you can use the @samp{.symver} directive to
specifically bind to an external version of the function in question.

You can also specify the language in the version script:

@smallexample
VERSION extern "lang" @{ version-script-commands @}
@end smallexample

The supported @samp{lang}s are @samp{C}, @samp{C++}, and @samp{Java}. 
The linker will iterate over the list of symbols at the link time and
demangle them according to @samp{lang} before matching them to the
patterns specified in @samp{version-script-commands}.

@node Expressions
@section Expressions in Linker Scripts
@cindex expressions
@cindex arithmetic
The syntax for expressions in the linker script language is identical to
that of C expressions.  All expressions are evaluated as integers.  All
expressions are evaluated in the same size, which is 32 bits if both the
host and target are 32 bits, and is otherwise 64 bits.

You can use and set symbol values in expressions.

The linker defines several special purpose builtin functions for use in
expressions.

@menu
* Constants::			Constants
* Symbols::			Symbol Names
* Location Counter::		The Location Counter
* Operators::			Operators
* Evaluation::			Evaluation
* Expression Section::		The Section of an Expression
* Builtin Functions::		Builtin Functions
@end menu

@node Constants
@subsection Constants
@cindex integer notation
@cindex constants in linker scripts
All constants are integers.

As in C, the linker considers an integer beginning with @samp{0} to be
octal, and an integer beginning with @samp{0x} or @samp{0X} to be
hexadecimal.  The linker considers other integers to be decimal.

@cindex scaled integers
@cindex K and M integer suffixes
@cindex M and K integer suffixes
@cindex suffixes for integers
@cindex integer suffixes
In addition, you can use the suffixes @code{K} and @code{M} to scale a
constant by
@c TEXI2ROFF-KILL
@ifinfo
@c END TEXI2ROFF-KILL
@code{1024} or @code{1024*1024}
@c TEXI2ROFF-KILL
@end ifinfo
@tex
${\rm 1024}$ or ${\rm 1024}^2$
@end tex
@c END TEXI2ROFF-KILL
respectively. For example, the following all refer to the same quantity:
@smallexample
  _fourk_1 = 4K;
  _fourk_2 = 4096;
  _fourk_3 = 0x1000;
@end smallexample

@node Symbols
@subsection Symbol Names
@cindex symbol names
@cindex names
@cindex quoted symbol names
@kindex "
Unless quoted, symbol names start with a letter, underscore, or period
and may include letters, digits, underscores, periods, and hyphens.
Unquoted symbol names must not conflict with any keywords.  You can
specify a symbol which contains odd characters or has the same name as a
keyword by surrounding the symbol name in double quotes:
@smallexample
  "SECTION" = 9;
  "with a space" = "also with a space" + 10;
@end smallexample

Since symbols can contain many non-alphabetic characters, it is safest
to delimit symbols with spaces.  For example, @samp{A-B} is one symbol,
whereas @samp{A - B} is an expression involving subtraction.

@node Location Counter
@subsection The Location Counter
@kindex .
@cindex dot
@cindex location counter
@cindex current output location
The special linker variable @dfn{dot} @samp{.} always contains the
current output location counter.  Since the @code{.} always refers to a
location in an output section, it may only appear in an expression
within a @code{SECTIONS} command.  The @code{.} symbol may appear
anywhere that an ordinary symbol is allowed in an expression.

@cindex holes
Assigning a value to @code{.} will cause the location counter to be
moved.  This may be used to create holes in the output section.  The
location counter may never be moved backwards.

@smallexample
SECTIONS
@{
  output :
    @{
      file1(.text)
      . = . + 1000;
      file2(.text)
      . += 1000;
      file3(.text)
    @} = 0x12345678;
@}
@end smallexample
@noindent
In the previous example, the @samp{.text} section from @file{file1} is
located at the beginning of the output section @samp{output}.  It is
followed by a 1000 byte gap.  Then the @samp{.text} section from
@file{file2} appears, also with a 1000 byte gap following before the
@samp{.text} section from @file{file3}.  The notation @samp{= 0x12345678}
specifies what data to write in the gaps (@pxref{Output Section Fill}).

@cindex dot inside sections
Note: @code{.} actually refers to the byte offset from the start of the
current containing object.  Normally this is the @code{SECTIONS}
statement, whoes start address is 0, hence @code{.} can be used as an
absolute address.  If @code{.} is used inside a section description
however, it refers to the byte offset from the start of that section,
not an absolute address.  Thus in a script like this:

@smallexample
SECTIONS
@{
    . = 0x100
    .text: @{
      *(.text)
      . = 0x200
    @}
    . = 0x500
    .data: @{
      *(.data)
      . += 0x600
    @}
@}
@end smallexample

The @samp{.text} section will be assigned a starting address of 0x100
and a size of exactly 0x200 bytes, even if there is not enough data in
the @samp{.text} input sections to fill this area.  (If there is too
much data, an error will be produced because this would be an attempt to
move @code{.} backwards).  The @samp{.data} section will start at 0x500
and it will have an extra 0x600 bytes worth of space after the end of
the values from the @samp{.data} input sections and before the end of
the @samp{.data} output section itself.

@need 2000
@node Operators
@subsection Operators
@cindex operators for arithmetic
@cindex arithmetic operators
@cindex precedence in expressions
The linker recognizes the standard C set of arithmetic operators, with
the standard bindings and precedence levels:
@c TEXI2ROFF-KILL
@ifinfo
@c END TEXI2ROFF-KILL
@smallexample
precedence      associativity   Operators                Notes
(highest)
1               left            !  -  ~                  (1)
2               left            *  /  %
3               left            +  -
4               left            >>  <<
5               left            ==  !=  >  <  <=  >=
6               left            &
7               left            |
8               left            &&
9               left            ||
10              right           ? :
11              right           &=  +=  -=  *=  /=       (2)
(lowest)
@end smallexample
Notes:
(1) Prefix operators
(2) @xref{Assignments}.
@c TEXI2ROFF-KILL
@end ifinfo
@tex
\vskip \baselineskip
%"lispnarrowing" is the extra indent used generally for smallexample
\hskip\lispnarrowing\vbox{\offinterlineskip
\hrule
\halign
{\vrule#&\strut\hfil\ #\ \hfil&\vrule#&\strut\hfil\ #\ \hfil&\vrule#&\strut\hfil\ {\tt #}\ \hfil&\vrule#\cr
height2pt&\omit&&\omit&&\omit&\cr
&Precedence&&  Associativity  &&{\rm Operators}&\cr
height2pt&\omit&&\omit&&\omit&\cr
\noalign{\hrule}
height2pt&\omit&&\omit&&\omit&\cr
&highest&&&&&\cr
% '176 is tilde, '~' in tt font
&1&&left&&\qquad-          \char'176\      !\qquad\dag&\cr
&2&&left&&*          /        \%&\cr
&3&&left&&+          -&\cr
&4&&left&&>>         <<&\cr
&5&&left&&==         !=       >      <      <=      >=&\cr
&6&&left&&\&&\cr
&7&&left&&|&\cr
&8&&left&&{\&\&}&\cr
&9&&left&&||&\cr
&10&&right&&?        :&\cr
&11&&right&&\qquad\&=      +=       -=     *=     /=\qquad\ddag&\cr
&lowest&&&&&\cr
height2pt&\omit&&\omit&&\omit&\cr}
\hrule}
@end tex
@iftex
{
@obeylines@parskip=0pt@parindent=0pt
@dag@quad Prefix operators.
@ddag@quad @xref{Assignments}.
}
@end iftex
@c END TEXI2ROFF-KILL

@node Evaluation
@subsection Evaluation
@cindex lazy evaluation
@cindex expression evaluation order
The linker evaluates expressions lazily.  It only computes the value of
an expression when absolutely necessary.

The linker needs some information, such as the value of the start
address of the first section, and the origins and lengths of memory
regions, in order to do any linking at all.  These values are computed
as soon as possible when the linker reads in the linker script.

However, other values (such as symbol values) are not known or needed
until after storage allocation.  Such values are evaluated later, when
other information (such as the sizes of output sections) is available
for use in the symbol assignment expression.

The sizes of sections cannot be known until after allocation, so
assignments dependent upon these are not performed until after
allocation.

Some expressions, such as those depending upon the location counter
@samp{.}, must be evaluated during section allocation.

If the result of an expression is required, but the value is not
available, then an error results.  For example, a script like the
following
@smallexample
@group
SECTIONS
  @{
    .text 9+this_isnt_constant :
      @{ *(.text) @}
  @}
@end group
@end smallexample
@noindent
will cause the error message @samp{non constant expression for initial
address}.

@node Expression Section
@subsection The Section of an Expression
@cindex expression sections
@cindex absolute expressions
@cindex relative expressions
@cindex absolute and relocatable symbols
@cindex relocatable and absolute symbols
@cindex symbols, relocatable and absolute
When the linker evaluates an expression, the result is either absolute
or relative to some section.  A relative expression is expressed as a
fixed offset from the base of a section.

The position of the expression within the linker script determines
whether it is absolute or relative.  An expression which appears within
an output section definition is relative to the base of the output
section.  An expression which appears elsewhere will be absolute.

A symbol set to a relative expression will be relocatable if you request
relocatable output using the @samp{-r} option.  That means that a
further link operation may change the value of the symbol.  The symbol's
section will be the section of the relative expression.

A symbol set to an absolute expression will retain the same value
through any further link operation.  The symbol will be absolute, and
will not have any particular associated section.

You can use the builtin function @code{ABSOLUTE} to force an expression
to be absolute when it would otherwise be relative.  For example, to
create an absolute symbol set to the address of the end of the output
section @samp{.data}:
@smallexample
SECTIONS
  @{
    .data : @{ *(.data) _edata = ABSOLUTE(.); @}
  @}
@end smallexample
@noindent
If @samp{ABSOLUTE} were not used, @samp{_edata} would be relative to the
@samp{.data} section.

@node Builtin Functions
@subsection Builtin Functions
@cindex functions in expressions
The linker script language includes a number of builtin functions for
use in linker script expressions.

@table @code
@item ABSOLUTE(@var{exp})
@kindex ABSOLUTE(@var{exp})
@cindex expression, absolute
Return the absolute (non-relocatable, as opposed to non-negative) value
of the expression @var{exp}.  Primarily useful to assign an absolute
value to a symbol within a section definition, where symbol values are
normally section relative.  @xref{Expression Section}.

@item ADDR(@var{section})
@kindex ADDR(@var{section})
@cindex section address in expression
Return the absolute address (the VMA) of the named @var{section}.  Your
script must previously have defined the location of that section.  In
the following example, @code{symbol_1} and @code{symbol_2} are assigned
identical values:
@smallexample
@group
SECTIONS @{ @dots{}
  .output1 :
    @{
    start_of_output_1 = ABSOLUTE(.);
    @dots{}
    @}
  .output :
    @{
    symbol_1 = ADDR(.output1);
    symbol_2 = start_of_output_1;
    @}
@dots{} @}
@end group
@end smallexample

@item ALIGN(@var{exp})
@kindex ALIGN(@var{exp})
@cindex round up location counter
@cindex align location counter
Return the location counter (@code{.}) aligned to the next @var{exp}
boundary.  @var{exp} must be an expression whose value is a power of
two.  This is equivalent to
@smallexample
(. + @var{exp} - 1) & ~(@var{exp} - 1)
@end smallexample

@code{ALIGN} doesn't change the value of the location counter---it just
does arithmetic on it.  Here is an example which aligns the output
@code{.data} section to the next @code{0x2000} byte boundary after the
preceding section and sets a variable within the section to the next
@code{0x8000} boundary after the input sections:
@smallexample
@group
SECTIONS @{ @dots{}
  .data ALIGN(0x2000): @{
    *(.data)
    variable = ALIGN(0x8000);
  @}
@dots{} @}
@end group
@end smallexample
@noindent
The first use of @code{ALIGN} in this example specifies the location of
a section because it is used as the optional @var{address} attribute of
a section definition (@pxref{Output Section Address}).  The second use
of @code{ALIGN} is used to defines the value of a symbol.

The builtin function @code{NEXT} is closely related to @code{ALIGN}.

@item BLOCK(@var{exp})
@kindex BLOCK(@var{exp})
This is a synonym for @code{ALIGN}, for compatibility with older linker
scripts.  It is most often seen when setting the address of an output
section.

@item DATA_SEGMENT_ALIGN(@var{maxpagesize}, @var{commonpagesize})
@kindex DATA_SEGMENT_ALIGN(@var{maxpagesize}, @var{commonpagesize})
This is equivalent to either
@smallexample
(ALIGN(@var{maxpagesize}) + (. & (@var{maxpagesize} - 1)))
@end smallexample
or
@smallexample
(ALIGN(@var{maxpagesize}) + (. & (@var{maxpagesize} - @var{commonpagesize})))
@end smallexample
@noindent
depending on whether the latter uses fewer @var{commonpagesize} sized pages
for the data segment (area between the result of this expression and
@code{DATA_SEGMENT_END}) than the former or not.
If the latter form is used, it means @var{commonpagesize} bytes of runtime
memory will be saved at the expense of up to @var{commonpagesize} wasted
bytes in the on-disk file.

This expression can only be used directly in @code{SECTIONS} commands, not in
any output section descriptions and only once in the linker script.
@var{commonpagesize} should be less or equal to @var{maxpagesize} and should
be the system page size the object wants to be optimized for (while still
working on system page sizes up to @var{maxpagesize}).

@noindent
Example:
@smallexample
  . = DATA_SEGMENT_ALIGN(0x10000, 0x2000);
@end smallexample

@item DATA_SEGMENT_END(@var{exp})
@kindex DATA_SEGMENT_END(@var{exp})
This defines the end of data segment for @code{DATA_SEGMENT_ALIGN}
evaluation purposes.

@smallexample
  . = DATA_SEGMENT_END(.);
@end smallexample

@item DEFINED(@var{symbol})
@kindex DEFINED(@var{symbol})
@cindex symbol defaults
Return 1 if @var{symbol} is in the linker global symbol table and is
defined, otherwise return 0.  You can use this function to provide
default values for symbols.  For example, the following script fragment
shows how to set a global symbol @samp{begin} to the first location in
the @samp{.text} section---but if a symbol called @samp{begin} already
existed, its value is preserved:

@smallexample
@group
SECTIONS @{ @dots{}
  .text : @{
    begin = DEFINED(begin) ? begin : . ;
    @dots{}
  @}
  @dots{}
@}
@end group
@end smallexample

@item LOADADDR(@var{section})
@kindex LOADADDR(@var{section})
@cindex section load address in expression
Return the absolute LMA of the named @var{section}.  This is normally
the same as @code{ADDR}, but it may be different if the @code{AT}
attribute is used in the output section definition (@pxref{Output
Section LMA}).

@kindex MAX
@item MAX(@var{exp1}, @var{exp2})
Returns the maximum of @var{exp1} and @var{exp2}.

@kindex MIN
@item MIN(@var{exp1}, @var{exp2})
Returns the minimum of @var{exp1} and @var{exp2}.

@item NEXT(@var{exp})
@kindex NEXT(@var{exp})
@cindex unallocated address, next
Return the next unallocated address that is a multiple of @var{exp}.
This function is closely related to @code{ALIGN(@var{exp})}; unless you
use the @code{MEMORY} command to define discontinuous memory for the
output file, the two functions are equivalent.

@item SIZEOF(@var{section})
@kindex SIZEOF(@var{section})
@cindex section size
Return the size in bytes of the named @var{section}, if that section has
been allocated.  If the section has not been allocated when this is
evaluated, the linker will report an error.  In the following example,
@code{symbol_1} and @code{symbol_2} are assigned identical values:
@smallexample
@group
SECTIONS@{ @dots{}
  .output @{
    .start = . ;
    @dots{}
    .end = . ;
    @}
  symbol_1 = .end - .start ;
  symbol_2 = SIZEOF(.output);
@dots{} @}
@end group
@end smallexample

@item SIZEOF_HEADERS
@itemx sizeof_headers
@kindex SIZEOF_HEADERS
@cindex header size
Return the size in bytes of the output file's headers.  This is
information which appears at the start of the output file.  You can use
this number when setting the start address of the first section, if you
choose, to facilitate paging.

@cindex not enough room for program headers
@cindex program headers, not enough room
When producing an ELF output file, if the linker script uses the
@code{SIZEOF_HEADERS} builtin function, the linker must compute the
number of program headers before it has determined all the section
addresses and sizes.  If the linker later discovers that it needs
additional program headers, it will report an error @samp{not enough
room for program headers}.  To avoid this error, you must avoid using
the @code{SIZEOF_HEADERS} function, or you must rework your linker
script to avoid forcing the linker to use additional program headers, or
you must define the program headers yourself using the @code{PHDRS}
command (@pxref{PHDRS}).
@end table

@node Implicit Linker Scripts
@section Implicit Linker Scripts
@cindex implicit linker scripts
If you specify a linker input file which the linker can not recognize as
an object file or an archive file, it will try to read the file as a
linker script.  If the file can not be parsed as a linker script, the
linker will report an error.

An implicit linker script will not replace the default linker script.

Typically an implicit linker script would contain only symbol
assignments, or the @code{INPUT}, @code{GROUP}, or @code{VERSION}
commands.

Any input files read because of an implicit linker script will be read
at the position in the command line where the implicit linker script was
read.  This can affect archive searching.

@ifset GENERIC
@node Machine Dependent
@chapter Machine Dependent Features

@cindex machine dependencies
@command{ld} has additional features on some platforms; the following
sections describe them.  Machines where @command{ld} has no additional
functionality are not listed.

@menu
* H8/300::                      @code{ld} and the H8/300
* i960::                        @code{ld} and the Intel 960 family
* ARM::				@code{ld} and the ARM family
* HPPA ELF32::                  @code{ld} and HPPA 32-bit ELF
@ifset MMIX
* MMIX::			@code{ld} and MMIX
@end ifset
@ifset TICOFF
* TI COFF::                     @command{ld} and TI COFF
@end ifset
@end menu
@end ifset

@c FIXME!  This could use @raisesections/@lowersections, but there seems to be a conflict
@c         between those and node-defaulting.
@ifset H8300
@ifclear GENERIC
@raisesections
@end ifclear

@node H8/300
@section @command{ld} and the H8/300

@cindex H8/300 support
For the H8/300, @command{ld} can perform these global optimizations when
you specify the @samp{--relax} command-line option.

@table @emph
@cindex relaxing on H8/300
@item relaxing address modes
@command{ld} finds all @code{jsr} and @code{jmp} instructions whose
targets are within eight bits, and turns them into eight-bit
program-counter relative @code{bsr} and @code{bra} instructions,
respectively.

@cindex synthesizing on H8/300
@item synthesizing instructions
@c FIXME: specifically mov.b, or any mov instructions really?
@command{ld} finds all @code{mov.b} instructions which use the
sixteen-bit absolute address form, but refer to the top
page of memory, and changes them to use the eight-bit address form.
(That is: the linker turns @samp{mov.b @code{@@}@var{aa}:16} into
@samp{mov.b @code{@@}@var{aa}:8} whenever the address @var{aa} is in the
top page of memory).
@end table

@ifclear GENERIC
@lowersections
@end ifclear
@end ifset

@ifclear GENERIC
@ifset Hitachi
@c This stuff is pointless to say unless you're especially concerned
@c with Hitachi chips; don't enable it for generic case, please.
@node Hitachi
@chapter @command{ld} and other Hitachi chips

@command{ld} also supports the H8/300H, the H8/500, and the Hitachi SH.  No
special features, commands, or command-line options are required for
these chips.
@end ifset
@end ifclear

@ifset I960
@ifclear GENERIC
@raisesections
@end ifclear

@node i960
@section @command{ld} and the Intel 960 family

@cindex i960 support

You can use the @samp{-A@var{architecture}} command line option to
specify one of the two-letter names identifying members of the 960
family; the option specifies the desired output target, and warns of any
incompatible instructions in the input files.  It also modifies the
linker's search strategy for archive libraries, to support the use of
libraries specific to each particular architecture, by including in the
search loop names suffixed with the string identifying the architecture.

For example, if your @command{ld} command line included @w{@samp{-ACA}} as
well as @w{@samp{-ltry}}, the linker would look (in its built-in search
paths, and in any paths you specify with @samp{-L}) for a library with
the names

@smallexample
@group
try
libtry.a
tryca
libtryca.a
@end group
@end smallexample

@noindent
The first two possibilities would be considered in any event; the last
two are due to the use of @w{@samp{-ACA}}.

You can meaningfully use @samp{-A} more than once on a command line, since
the 960 architecture family allows combination of target architectures; each
use will add another pair of name variants to search for when @w{@samp{-l}}
specifies a library.

@cindex @option{--relax} on i960
@cindex relaxing on i960
@command{ld} supports the @samp{--relax} option for the i960 family.  If
you specify @samp{--relax}, @command{ld} finds all @code{balx} and
@code{calx} instructions whose targets are within 24 bits, and turns
them into 24-bit program-counter relative @code{bal} and @code{cal}
instructions, respectively.  @command{ld} also turns @code{cal}
instructions into @code{bal} instructions when it determines that the
target subroutine is a leaf routine (that is, the target subroutine does
not itself call any subroutines).

@ifclear GENERIC
@lowersections
@end ifclear
@end ifset

@ifclear GENERIC
@raisesections
@end ifclear

@node ARM
@section @command{ld}'s support for interworking between ARM and Thumb code

@cindex ARM interworking support
@kindex --support-old-code
For the ARM, @command{ld} will generate code stubs to allow functions calls
betweem ARM and Thumb code.  These stubs only work with code that has
been compiled and assembled with the @samp{-mthumb-interwork} command
line option.  If it is necessary to link with old ARM object files or
libraries, which have not been compiled with the -mthumb-interwork
option then the @samp{--support-old-code} command line switch should be
given to the linker.  This will make it generate larger stub functions
which will work with non-interworking aware ARM code.  Note, however,
the linker does not support generating stubs for function calls to
non-interworking aware Thumb code.

@cindex thumb entry point
@cindex entry point, thumb
@kindex --thumb-entry=@var{entry}
The @samp{--thumb-entry} switch is a duplicate of the generic
@samp{--entry} switch, in that it sets the program's starting address.
But it also sets the bottom bit of the address, so that it can be
branched to using a BX instruction, and the program will start
executing in Thumb mode straight away.

@node HPPA ELF32
@section @command{ld} and HPPA 32-bit ELF support
@cindex HPPA multiple sub-space stubs
@kindex --multi-subspace
When generating a shared library, @command{ld} will by default generate
import stubs suitable for use with a single sub-space application.
The @samp{--multi-subspace} switch causes @command{ld} to generate export
stubs, and different (larger) import stubs suitable for use with
multiple sub-spaces.

@cindex HPPA stub grouping
@kindex --stub-group-size=@var{N}
Long branch stubs and import/export stubs are placed by @command{ld} in
stub sections located between groups of input sections.
@samp{--stub-group-size} specifies the maximum size of a group of input
sections handled by one stub section.  Since branch offsets are signed,
a stub section may serve two groups of input sections, one group before
the stub section, and one group after it.  However, when using
conditional branches that require stubs, it may be better (for branch
prediction) that stub sections only serve one group of input sections.
A negative value for @samp{N} chooses this scheme, ensuring that
branches to stubs always use a negative offset.  Two special values of
@samp{N} are recognized, @samp{1} and @samp{-1}.  These both instruct
@command{ld} to automatically size input section groups for the branch types
detected, with the same behaviour regarding stub placement as other
positive or negative values of @samp{N} respectively.

Note that @samp{--stub-group-size} does not split input sections.  A
single input section larger than the group size specified will of course
create a larger group (of one section).  If input sections are too
large, it may not be possible for a branch to reach its stub.

@ifset MMIX
@node MMIX
@section @code{ld} and MMIX
For MMIX, there is choice of generating @code{ELF} object files or
@code{mmo} object files when linking.  The simulator @code{mmix}
understands the @code{mmo} format.  The binutils @code{objcopy} utility
can translate between the two formats.

There is one special section, the @samp{.MMIX.reg_contents} section.
Contents in this section is assumed to correspond to that of global
registers, and symbols referring to it are translated to special symbols,
equal to registers.  In a final link, the start address of the
@samp{.MMIX.reg_contents} section corresponds to the first allocated
global register multiplied by 8.  Register @code{$255} is not included in
this section; it is always set to the program entry, which is at the
symbol @code{Main} for @code{mmo} files.

Symbols with the prefix @code{__.MMIX.start.}, for example
@code{__.MMIX.start..text} and @code{__.MMIX.start..data} are special;
there must be only one each, even if they are local.  The default linker
script uses these to set the default start address of a section.

Initial and trailing multiples of zero-valued 32-bit words in a section,
are left out from an mmo file.
@end ifset

@ifset TICOFF
@node TI COFF
@section @command{ld}'s support for various TI COFF versions
@cindex TI COFF versions
@kindex --format=@var{version}
The @samp{--format} switch allows selection of one of the various
TI COFF versions.  The latest of this writing is 2; versions 0 and 1 are
also supported.  The TI COFF versions also vary in header byte-order
format; @command{ld} will read any version or byte order, but the output
header format depends on the default specified by the specific target.
@end ifset

@ifclear GENERIC
@lowersections
@end ifclear

@ifclear SingleFormat
@node BFD
@chapter BFD

@cindex back end
@cindex object file management
@cindex object formats available
@kindex objdump -i
The linker accesses object and archive files using the BFD libraries.
These libraries allow the linker to use the same routines to operate on
object files whatever the object file format.  A different object file
format can be supported simply by creating a new BFD back end and adding
it to the library.  To conserve runtime memory, however, the linker and
associated tools are usually configured to support only a subset of the
object file formats available.  You can use @code{objdump -i}
(@pxref{objdump,,objdump,binutils.info,The GNU Binary Utilities}) to
list all the formats available for your configuration.

@cindex BFD requirements
@cindex requirements for BFD
As with most implementations, BFD is a compromise between
several conflicting requirements. The major factor influencing
BFD design was efficiency: any time used converting between
formats is time which would not have been spent had BFD not
been involved. This is partly offset by abstraction payback; since
BFD simplifies applications and back ends, more time and care
may be spent optimizing algorithms for a greater speed.

One minor artifact of the BFD solution which you should bear in
mind is the potential for information loss.  There are two places where
useful information can be lost using the BFD mechanism: during
conversion and during output. @xref{BFD information loss}.

@menu
* BFD outline::                 How it works: an outline of BFD
@end menu

@node BFD outline
@section How it works: an outline of BFD
@cindex opening object files
@include bfdsumm.texi
@end ifclear

@node Reporting Bugs
@chapter Reporting Bugs
@cindex bugs in @command{ld}
@cindex reporting bugs in @command{ld}

Your bug reports play an essential role in making @command{ld} reliable.

Reporting a bug may help you by bringing a solution to your problem, or
it may not.  But in any case the principal function of a bug report is
to help the entire community by making the next version of @command{ld}
work better.  Bug reports are your contribution to the maintenance of
@command{ld}.

In order for a bug report to serve its purpose, you must include the
information that enables us to fix the bug.

@menu
* Bug Criteria::                Have you found a bug?
* Bug Reporting::               How to report bugs
@end menu

@node Bug Criteria
@section Have you found a bug?
@cindex bug criteria

If you are not sure whether you have found a bug, here are some guidelines:

@itemize @bullet
@cindex fatal signal
@cindex linker crash
@cindex crash of linker
@item
If the linker gets a fatal signal, for any input whatever, that is a
@command{ld} bug.  Reliable linkers never crash.

@cindex error on valid input
@item
If @command{ld} produces an error message for valid input, that is a bug.

@cindex invalid input
@item
If @command{ld} does not produce an error message for invalid input, that
may be a bug.  In the general case, the linker can not verify that
object files are correct.

@item
If you are an experienced user of linkers, your suggestions for
improvement of @command{ld} are welcome in any case.
@end itemize

@node Bug Reporting
@section How to report bugs
@cindex bug reports
@cindex @command{ld} bugs, reporting

A number of companies and individuals offer support for @sc{gnu}
products.  If you obtained @command{ld} from a support organization, we
recommend you contact that organization first.

You can find contact information for many support companies and
individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
distribution.

Otherwise, send bug reports for @command{ld} to
@samp{bug-binutils@@gnu.org}.

The fundamental principle of reporting bugs usefully is this:
@strong{report all the facts}.  If you are not sure whether to state a
fact or leave it out, state it!

Often people omit facts because they think they know what causes the
problem and assume that some details do not matter.  Thus, you might
assume that the name of a symbol you use in an example does not matter.
Well, probably it does not, but one cannot be sure.  Perhaps the bug is
a stray memory reference which happens to fetch from the location where
that name is stored in memory; perhaps, if the name were different, the
contents of that location would fool the linker into doing the right
thing despite the bug.  Play it safe and give a specific, complete
example.  That is the easiest thing for you to do, and the most helpful.

Keep in mind that the purpose of a bug report is to enable us to fix the bug if
it is new to us.  Therefore, always write your bug reports on the assumption
that the bug has not been reported previously.

Sometimes people give a few sketchy facts and ask, ``Does this ring a
bell?''  Those bug reports are useless, and we urge everyone to
@emph{refuse to respond to them} except to chide the sender to report
bugs properly.

To enable us to fix the bug, you should include all these things:

@itemize @bullet
@item
The version of @command{ld}.  @command{ld} announces it if you start it with
the @samp{--version} argument.

Without this, we will not know whether there is any point in looking for
the bug in the current version of @command{ld}.

@item
Any patches you may have applied to the @command{ld} source, including any
patches made to the @code{BFD} library.

@item
The type of machine you are using, and the operating system name and
version number.

@item
What compiler (and its version) was used to compile @command{ld}---e.g.
``@code{gcc-2.7}''.

@item
The command arguments you gave the linker to link your example and
observe the bug.  To guarantee you will not omit something important,
list them all.  A copy of the Makefile (or the output from make) is
sufficient.

If we were to try to guess the arguments, we would probably guess wrong
and then we might not encounter the bug.

@item
A complete input file, or set of input files, that will reproduce the
bug.  It is generally most helpful to send the actual object files,
uuencoded if necessary to get them through the mail system.  Making them
available for anonymous FTP is not as good, but may be the only
reasonable choice for large object files.

If the source files were assembled using @code{gas} or compiled using
@code{gcc}, then it may be OK to send the source files rather than the
object files.  In this case, be sure to say exactly what version of
@code{gas} or @code{gcc} was used to produce the object files.  Also say
how @code{gas} or @code{gcc} were configured.

@item
A description of what behavior you observe that you believe is
incorrect.  For example, ``It gets a fatal signal.''

Of course, if the bug is that @command{ld} gets a fatal signal, then we
will certainly notice it.  But if the bug is incorrect output, we might
not notice unless it is glaringly wrong.  You might as well not give us
a chance to make a mistake.

Even if the problem you experience is a fatal signal, you should still
say so explicitly.  Suppose something strange is going on, such as, your
copy of @command{ld} is out of synch, or you have encountered a bug in the
C library on your system.  (This has happened!)  Your copy might crash
and ours would not.  If you told us to expect a crash, then when ours
fails to crash, we would know that the bug was not happening for us.  If
you had not told us to expect a crash, then we would not be able to draw
any conclusion from our observations.

@item
If you wish to suggest changes to the @command{ld} source, send us context
diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or
@samp{-p} option.  Always send diffs from the old file to the new file.
If you even discuss something in the @command{ld} source, refer to it by
context, not by line number.

The line numbers in our development sources will not match those in your
sources.  Your line numbers would convey no useful information to us.
@end itemize

Here are some things that are not necessary:

@itemize @bullet
@item
A description of the envelope of the bug.

Often people who encounter a bug spend a lot of time investigating
which changes to the input file will make the bug go away and which
changes will not affect it.

This is often time consuming and not very useful, because the way we
will find the bug is by running a single example under the debugger
with breakpoints, not by pure deduction from a series of examples.
We recommend that you save your time for something else.

Of course, if you can find a simpler example to report @emph{instead}
of the original one, that is a convenience for us.  Errors in the
output will be easier to spot, running under the debugger will take
less time, and so on.

However, simplification is not vital; if you do not want to do this,
report the bug anyway and send us the entire test case you used.

@item
A patch for the bug.

A patch for the bug does help us if it is a good one.  But do not omit
the necessary information, such as the test case, on the assumption that
a patch is all we need.  We might see problems with your patch and decide
to fix the problem another way, or we might not understand it at all.

Sometimes with a program as complicated as @command{ld} it is very hard to
construct an example that will make the program follow a certain path
through the code.  If you do not send us the example, we will not be
able to construct one, so we will not be able to verify that the bug is
fixed.

And if we cannot understand what bug you are trying to fix, or why your
patch should be an improvement, we will not install it.  A test case will
help us to understand.

@item
A guess about what the bug is or what it depends on.

Such guesses are usually wrong.  Even we cannot guess right about such
things without first using the debugger to find the facts.
@end itemize

@node MRI
@appendix MRI Compatible Script Files
@cindex MRI compatibility
To aid users making the transition to @sc{gnu} @command{ld} from the MRI
linker, @command{ld} can use MRI compatible linker scripts as an
alternative to the more general-purpose linker scripting language
described in @ref{Scripts}.  MRI compatible linker scripts have a much
simpler command set than the scripting language otherwise used with
@command{ld}.  @sc{gnu} @command{ld} supports the most commonly used MRI
linker commands; these commands are described here.

In general, MRI scripts aren't of much use with the @code{a.out} object
file format, since it only has three sections and MRI scripts lack some
features to make use of them.

You can specify a file containing an MRI-compatible script using the
@samp{-c} command-line option.

Each command in an MRI-compatible script occupies its own line; each
command line starts with the keyword that identifies the command (though
blank lines are also allowed for punctuation).  If a line of an
MRI-compatible script begins with an unrecognized keyword, @command{ld}
issues a warning message, but continues processing the script.

Lines beginning with @samp{*} are comments.

You can write these commands using all upper-case letters, or all
lower case; for example, @samp{chip} is the same as @samp{CHIP}.
The following list shows only the upper-case form of each command.

@table @code
@cindex @code{ABSOLUTE} (MRI)
@item ABSOLUTE @var{secname}
@itemx ABSOLUTE @var{secname}, @var{secname}, @dots{} @var{secname}
Normally, @command{ld} includes in the output file all sections from all
the input files.  However, in an MRI-compatible script, you can use the
@code{ABSOLUTE} command to restrict the sections that will be present in
your output program.  If the @code{ABSOLUTE} command is used at all in a
script, then only the sections named explicitly in @code{ABSOLUTE}
commands will appear in the linker output.  You can still use other
input sections (whatever you select on the command line, or using
@code{LOAD}) to resolve addresses in the output file.

@cindex @code{ALIAS} (MRI)
@item ALIAS @var{out-secname}, @var{in-secname}
Use this command to place the data from input section @var{in-secname}
in a section called @var{out-secname} in the linker output file.

@var{in-secname} may be an integer.

@cindex @code{ALIGN} (MRI)
@item ALIGN @var{secname} = @var{expression}
Align the section called @var{secname} to @var{expression}.  The
@var{expression} should be a power of two.

@cindex @code{BASE} (MRI)
@item BASE @var{expression}
Use the value of @var{expression} as the lowest address (other than
absolute addresses) in the output file.

@cindex @code{CHIP} (MRI)
@item CHIP @var{expression}
@itemx CHIP @var{expression}, @var{expression}
This command does nothing; it is accepted only for compatibility.

@cindex @code{END} (MRI)
@item END
This command does nothing whatever; it's only accepted for compatibility.

@cindex @code{FORMAT} (MRI)
@item FORMAT @var{output-format}
Similar to the @code{OUTPUT_FORMAT} command in the more general linker
language, but restricted to one of these output formats:

@enumerate
@item
S-records, if @var{output-format} is @samp{S}

@item
IEEE, if @var{output-format} is @samp{IEEE}

@item
COFF (the @samp{coff-m68k} variant in BFD), if @var{output-format} is
@samp{COFF}
@end enumerate

@cindex @code{LIST} (MRI)
@item LIST @var{anything}@dots{}
Print (to the standard output file) a link map, as produced by the
@command{ld} command-line option @samp{-M}.

The keyword @code{LIST} may be followed by anything on the
same line, with no change in its effect.

@cindex @code{LOAD} (MRI)
@item LOAD @var{filename}
@itemx LOAD @var{filename}, @var{filename}, @dots{} @var{filename}
Include one or more object file @var{filename} in the link; this has the
same effect as specifying @var{filename} directly on the @command{ld}
command line.

@cindex @code{NAME} (MRI)
@item NAME @var{output-name}
@var{output-name} is the name for the program produced by @command{ld}; the
MRI-compatible command @code{NAME} is equivalent to the command-line
option @samp{-o} or the general script language command @code{OUTPUT}.

@cindex @code{ORDER} (MRI)
@item ORDER @var{secname}, @var{secname}, @dots{} @var{secname}
@itemx ORDER @var{secname} @var{secname} @var{secname}
Normally, @command{ld} orders the sections in its output file in the
order in which they first appear in the input files.  In an MRI-compatible
script, you can override this ordering with the @code{ORDER} command.  The
sections you list with @code{ORDER} will appear first in your output
file, in the order specified.

@cindex @code{PUBLIC} (MRI)
@item PUBLIC @var{name}=@var{expression}
@itemx PUBLIC @var{name},@var{expression}
@itemx PUBLIC @var{name} @var{expression}
Supply a value (@var{expression}) for external symbol
@var{name} used in the linker input files.

@cindex @code{SECT} (MRI)
@item SECT @var{secname}, @var{expression}
@itemx SECT @var{secname}=@var{expression}
@itemx SECT @var{secname} @var{expression}
You can use any of these three forms of the @code{SECT} command to
specify the start address (@var{expression}) for section @var{secname}.
If you have more than one @code{SECT} statement for the same
@var{secname}, only the @emph{first} sets the start address.
@end table

@node GNU Free Documentation License
@appendix GNU Free Documentation License
@cindex GNU Free Documentation License

                GNU Free Documentation License

                   Version 1.1, March 2000

 Copyright (C) 2000  Free Software Foundation, Inc.
  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.


0. PREAMBLE

The purpose of this License is to make a manual, textbook, or other
written document "free" in the sense of freedom: to assure everyone
the effective freedom to copy and redistribute it, with or without
modifying it, either commercially or noncommercially.  Secondarily,
this License preserves for the author and publisher a way to get
credit for their work, while not being considered responsible for
modifications made by others.

This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.  It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does.  But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book.  We recommend this License
principally for works whose purpose is instruction or reference.


1. APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work that contains a
notice placed by the copyright holder saying it can be distributed
under the terms of this License.  The "Document", below, refers to any
such manual or work.  Any member of the public is a licensee, and is
addressed as "you".

A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.

A "Secondary Section" is a named appendix or a front-matter section of
the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall subject
(or to related matters) and contains nothing that could fall directly
within that overall subject.  (For example, if the Document is in part a
textbook of mathematics, a Secondary Section may not explain any
mathematics.)  The relationship could be a matter of historical
connection with the subject or with related matters, or of legal,
commercial, philosophical, ethical or political position regarding
them.

The "Invariant Sections" are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License.

The "Cover Texts" are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License.

A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, whose contents can be viewed and edited directly and
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or
for automatic translation to a variety of formats suitable for input
to text formatters.  A copy made in an otherwise Transparent file
format whose markup has been designed to thwart or discourage
subsequent modification by readers is not Transparent.  A copy that is
not "Transparent" is called "Opaque".

Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format, SGML
or XML using a publicly available DTD, and standard-conforming simple
HTML designed for human modification.  Opaque formats include
PostScript, PDF, proprietary formats that can be read and edited only
by proprietary word processors, SGML or XML for which the DTD and/or
processing tools are not generally available, and the
machine-generated HTML produced by some word processors for output
purposes only.

The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page.  For works in
formats which do not have any title page as such, "Title Page" means
the text near the most prominent appearance of the work's title,
preceding the beginning of the body of the text.


2. VERBATIM COPYING

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License.  You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute.  However, you may accept
compensation in exchange for copies.  If you distribute a large enough
number of copies you must also follow the conditions in section 3.

You may also lend copies, under the same conditions stated above, and
you may publicly display copies.


3. COPYING IN QUANTITY

If you publish printed copies of the Document numbering more than 100,
and the Document's license notice requires Cover Texts, you must enclose
the copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover.  Both covers must also clearly and legibly identify
you as the publisher of these copies.  The front cover must present
the full title with all words of the title equally prominent and
visible.  You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.

If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a publicly-accessible computer-network location containing a complete
Transparent copy of the Document, free of added material, which the
general network-using public has access to download anonymously at no
charge using public-standard network protocols.  If you use the latter
option, you must take reasonably prudent steps, when you begin
distribution of Opaque copies in quantity, to ensure that this
Transparent copy will remain thus accessible at the stated location
until at least one year after the last time you distribute an Opaque
copy (directly or through your agents or retailers) of that edition to
the public.

It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.


4. MODIFICATIONS

You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it.  In addition, you must do these things in the Modified Version:

A. Use in the Title Page (and on the covers, if any) a title distinct
   from that of the Document, and from those of previous versions
   (which should, if there were any, be listed in the History section
   of the Document).  You may use the same title as a previous version
   if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities
   responsible for authorship of the modifications in the Modified
   Version, together with at least five of the principal authors of the
   Document (all of its principal authors, if it has less than five).
C. State on the Title page the name of the publisher of the
   Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
   adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license notice
   giving the public permission to use the Modified Version under the
   terms of this License, in the form shown in the Addendum below.
G. Preserve in that license notice the full lists of Invariant Sections
   and required Cover Texts given in the Document's license notice.
H. Include an unaltered copy of this License.
I. Preserve the section entitled "History", and its title, and add to
   it an item stating at least the title, year, new authors, and
   publisher of the Modified Version as given on the Title Page.  If
   there is no section entitled "History" in the Document, create one
   stating the title, year, authors, and publisher of the Document as
   given on its Title Page, then add an item describing the Modified
   Version as stated in the previous sentence.
J. Preserve the network location, if any, given in the Document for
   public access to a Transparent copy of the Document, and likewise
   the network locations given in the Document for previous versions
   it was based on.  These may be placed in the "History" section.
   You may omit a network location for a work that was published at
   least four years before the Document itself, or if the original
   publisher of the version it refers to gives permission.
K. In any section entitled "Acknowledgements" or "Dedications",
   preserve the section's title, and preserve in the section all the
   substance and tone of each of the contributor acknowledgements
   and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document,
   unaltered in their text and in their titles.  Section numbers
   or the equivalent are not considered part of the section titles.
M. Delete any section entitled "Endorsements".  Such a section
   may not be included in the Modified Version.
N. Do not retitle any existing section as "Endorsements"
   or to conflict in title with any Invariant Section.

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant.  To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.

You may add a section entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version.  Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity.  If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.


5. COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy.  If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections entitled "History"
in the various original documents, forming one section entitled
"History"; likewise combine any sections entitled "Acknowledgements",
and any sections entitled "Dedications".  You must delete all sections
entitled "Endorsements."


6. COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all
other respects regarding verbatim copying of that document.


7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, does not as a whole count as a Modified Version
of the Document, provided no compilation copyright is claimed for the
compilation.  Such a compilation is called an "aggregate", and this
License does not apply to the other self-contained works thus compiled
with the Document, on account of their being thus compiled, if they
are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one quarter
of the entire aggregate, the Document's Cover Texts may be placed on
covers that surround only the Document within the aggregate.
Otherwise they must appear on covers around the whole aggregate.


8. TRANSLATION

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections.  You may include a
translation of this License provided that you also include the
original English version of this License.  In case of a disagreement
between the translation and the original English version of this
License, the original English version will prevail.


9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except
as expressly provided for under this License.  Any other attempt to
copy, modify, sublicense or distribute the Document is void, and will
automatically terminate your rights under this License.  However,
parties who have received copies, or rights, from you under this
License will not have their licenses terminated so long as such
parties remain in full compliance.


10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions
of the GNU Free Documentation License from time to time.  Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.  See
http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License "or any later version" applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation.  If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.


ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:

@smallexample
    Copyright (c)  YEAR  YOUR NAME.
    Permission is granted to copy, distribute and/or modify this document
    under the terms of the GNU Free Documentation License, Version 1.1
    or any later version published by the Free Software Foundation;
    with the Invariant Sections being LIST THEIR TITLES, with the
    Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
    A copy of the license is included in the section entitled "GNU
    Free Documentation License".
@end smallexample

If you have no Invariant Sections, write "with no Invariant Sections"
instead of saying which ones are invariant.  If you have no
Front-Cover Texts, write "no Front-Cover Texts" instead of
"Front-Cover Texts being LIST"; likewise for Back-Cover Texts.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.

@node Index
@unnumbered Index

@printindex cp

@tex
% I think something like @colophon should be in texinfo.  In the
% meantime:
\long\def\colophon{\hbox to0pt{}\vfill
\centerline{The body of this manual is set in}
\centerline{\fontname\tenrm,}
\centerline{with headings in {\bf\fontname\tenbf}}
\centerline{and examples in {\tt\fontname\tentt}.}
\centerline{{\it\fontname\tenit\/} and}
\centerline{{\sl\fontname\tensl\/}}
\centerline{are used for emphasis.}\vfill}
\page\colophon
% Blame: doc@cygnus.com, 28mar91.
@end tex


@contents
@bye