aboutsummaryrefslogtreecommitdiff
path: root/gold/layout.cc
blob: 76b6b2be8d109d544c84212e6ab3c0312a1749c0 (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
// layout.cc -- lay out output file sections for gold

// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

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

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

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

#include "gold.h"

#include <cerrno>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <utility>
#include <fcntl.h>
#include <unistd.h>
#include "libiberty.h"
#include "md5.h"
#include "sha1.h"

#include "parameters.h"
#include "options.h"
#include "script.h"
#include "script-sections.h"
#include "output.h"
#include "symtab.h"
#include "dynobj.h"
#include "ehframe.h"
#include "compressed_output.h"
#include "reloc.h"
#include "layout.h"

namespace gold
{

// Layout_task_runner methods.

// Lay out the sections.  This is called after all the input objects
// have been read.

void
Layout_task_runner::run(Workqueue* workqueue, const Task* task)
{
  off_t file_size = this->layout_->finalize(this->input_objects_,
					    this->symtab_,
                                            this->target_,
					    task);

  // Now we know the final size of the output file and we know where
  // each piece of information goes.
  Output_file* of = new Output_file(parameters->options().output_file_name());
  if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
    of->set_is_temporary();
  of->open(file_size);

  // Queue up the final set of tasks.
  gold::queue_final_tasks(this->options_, this->input_objects_,
			  this->symtab_, this->layout_, workqueue, of);
}

// Layout methods.

Layout::Layout(const General_options& options, Script_options* script_options)
  : options_(options), script_options_(script_options), namepool_(),
    sympool_(), dynpool_(), signatures_(),
    section_name_map_(), segment_list_(), section_list_(),
    unattached_section_list_(), sections_are_attached_(false),
    special_output_list_(), section_headers_(NULL), tls_segment_(NULL),
    symtab_section_(NULL), dynsym_section_(NULL), dynamic_section_(NULL),
    dynamic_data_(NULL), eh_frame_section_(NULL), eh_frame_data_(NULL),
    added_eh_frame_data_(false), eh_frame_hdr_section_(NULL),
    build_id_note_(NULL), group_signatures_(), output_file_size_(-1),
    input_requires_executable_stack_(false),
    input_with_gnu_stack_note_(false),
    input_without_gnu_stack_note_(false),
    has_static_tls_(false),
    any_postprocessing_sections_(false)
{
  // Make space for more than enough segments for a typical file.
  // This is just for efficiency--it's OK if we wind up needing more.
  this->segment_list_.reserve(12);

  // We expect two unattached Output_data objects: the file header and
  // the segment headers.
  this->special_output_list_.reserve(2);
}

// Hash a key we use to look up an output section mapping.

size_t
Layout::Hash_key::operator()(const Layout::Key& k) const
{
 return k.first + k.second.first + k.second.second;
}

// Return whether PREFIX is a prefix of STR.

static inline bool
is_prefix_of(const char* prefix, const char* str)
{
  return strncmp(prefix, str, strlen(prefix)) == 0;
}

// Returns whether the given section is in the list of
// debug-sections-used-by-some-version-of-gdb.  Currently,
// we've checked versions of gdb up to and including 6.7.1.

static const char* gdb_sections[] =
{ ".debug_abbrev",
  // ".debug_aranges",   // not used by gdb as of 6.7.1
  ".debug_frame",
  ".debug_info",
  ".debug_line",
  ".debug_loc",
  ".debug_macinfo",
  // ".debug_pubnames",  // not used by gdb as of 6.7.1
  ".debug_ranges",
  ".debug_str",
};

static inline bool
is_gdb_debug_section(const char* str)
{
  // We can do this faster: binary search or a hashtable.  But why bother?
  for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
    if (strcmp(str, gdb_sections[i]) == 0)
      return true;
  return false;
}

// Whether to include this section in the link.

template<int size, bool big_endian>
bool
Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
			const elfcpp::Shdr<size, big_endian>& shdr)
{
  switch (shdr.get_sh_type())
    {
    case elfcpp::SHT_NULL:
    case elfcpp::SHT_SYMTAB:
    case elfcpp::SHT_DYNSYM:
    case elfcpp::SHT_STRTAB:
    case elfcpp::SHT_HASH:
    case elfcpp::SHT_DYNAMIC:
    case elfcpp::SHT_SYMTAB_SHNDX:
      return false;

    case elfcpp::SHT_RELA:
    case elfcpp::SHT_REL:
    case elfcpp::SHT_GROUP:
      // If we are emitting relocations these should be handled
      // elsewhere.
      gold_assert(!parameters->options().relocatable()
		  && !parameters->options().emit_relocs());
      return false;

    case elfcpp::SHT_PROGBITS:
      if (parameters->options().strip_debug()
	  && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
	{
	  // Debugging sections can only be recognized by name.
	  if (is_prefix_of(".debug", name)
	      || is_prefix_of(".gnu.linkonce.wi.", name)
	      || is_prefix_of(".line", name)
	      || is_prefix_of(".stab", name))
	    return false;
	}
      if (parameters->options().strip_debug_gdb()
	  && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
	{
	  // Debugging sections can only be recognized by name.
	  if (is_prefix_of(".debug", name)
              && !is_gdb_debug_section(name))
	    return false;
	}
      return true;

    default:
      return true;
    }
}

// Return an output section named NAME, or NULL if there is none.

Output_section*
Layout::find_output_section(const char* name) const
{
  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    if (strcmp((*p)->name(), name) == 0)
      return *p;
  return NULL;
}

// Return an output segment of type TYPE, with segment flags SET set
// and segment flags CLEAR clear.  Return NULL if there is none.

Output_segment*
Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
			    elfcpp::Elf_Word clear) const
{
  for (Segment_list::const_iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    if (static_cast<elfcpp::PT>((*p)->type()) == type
	&& ((*p)->flags() & set) == set
	&& ((*p)->flags() & clear) == 0)
      return *p;
  return NULL;
}

// Return the output section to use for section NAME with type TYPE
// and section flags FLAGS.  NAME must be canonicalized in the string
// pool, and NAME_KEY is the key.

Output_section*
Layout::get_output_section(const char* name, Stringpool::Key name_key,
			   elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
{
  elfcpp::Elf_Xword lookup_flags = flags;

  // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
  // read-write with read-only sections.  Some other ELF linkers do
  // not do this.  FIXME: Perhaps there should be an option
  // controlling this.
  lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);

  const Key key(name_key, std::make_pair(type, lookup_flags));
  const std::pair<Key, Output_section*> v(key, NULL);
  std::pair<Section_name_map::iterator, bool> ins(
    this->section_name_map_.insert(v));

  if (!ins.second)
    return ins.first->second;
  else
    {
      // This is the first time we've seen this name/type/flags
      // combination.  For compatibility with the GNU linker, we
      // combine sections with contents and zero flags with sections
      // with non-zero flags.  This is a workaround for cases where
      // assembler code forgets to set section flags.  FIXME: Perhaps
      // there should be an option to control this.
      Output_section* os = NULL;

      if (type == elfcpp::SHT_PROGBITS)
	{
          if (flags == 0)
            {
              Output_section* same_name = this->find_output_section(name);
              if (same_name != NULL
                  && same_name->type() == elfcpp::SHT_PROGBITS
                  && (same_name->flags() & elfcpp::SHF_TLS) == 0)
                os = same_name;
            }
          else if ((flags & elfcpp::SHF_TLS) == 0)
            {
              elfcpp::Elf_Xword zero_flags = 0;
              const Key zero_key(name_key, std::make_pair(type, zero_flags));
              Section_name_map::iterator p =
                  this->section_name_map_.find(zero_key);
              if (p != this->section_name_map_.end())
		os = p->second;
            }
	}

      if (os == NULL)
	os = this->make_output_section(name, type, flags);
      ins.first->second = os;
      return os;
    }
}

// Pick the output section to use for section NAME, in input file
// RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
// linker created section.  IS_INPUT_SECTION is true if we are
// choosing an output section for an input section found in a input
// file.  This will return NULL if the input section should be
// discarded.

Output_section*
Layout::choose_output_section(const Relobj* relobj, const char* name,
			      elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
			      bool is_input_section)
{
  // We should not see any input sections after we have attached
  // sections to segments.
  gold_assert(!is_input_section || !this->sections_are_attached_);

  // Some flags in the input section should not be automatically
  // copied to the output section.
  flags &= ~ (elfcpp::SHF_INFO_LINK
	      | elfcpp::SHF_LINK_ORDER
	      | elfcpp::SHF_GROUP
	      | elfcpp::SHF_MERGE
	      | elfcpp::SHF_STRINGS);

  if (this->script_options_->saw_sections_clause())
    {
      // We are using a SECTIONS clause, so the output section is
      // chosen based only on the name.

      Script_sections* ss = this->script_options_->script_sections();
      const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
      Output_section** output_section_slot;
      name = ss->output_section_name(file_name, name, &output_section_slot);
      if (name == NULL)
	{
	  // The SECTIONS clause says to discard this input section.
	  return NULL;
	}

      // If this is an orphan section--one not mentioned in the linker
      // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
      // default processing below.

      if (output_section_slot != NULL)
	{
	  if (*output_section_slot != NULL)
	    return *output_section_slot;

	  // We don't put sections found in the linker script into
	  // SECTION_NAME_MAP_.  That keeps us from getting confused
	  // if an orphan section is mapped to a section with the same
	  // name as one in the linker script.

	  name = this->namepool_.add(name, false, NULL);

	  Output_section* os = this->make_output_section(name, type, flags);
	  os->set_found_in_sections_clause();
	  *output_section_slot = os;
	  return os;
	}
    }

  // FIXME: Handle SHF_OS_NONCONFORMING somewhere.

  // Turn NAME from the name of the input section into the name of the
  // output section.

  size_t len = strlen(name);
  if (is_input_section && !parameters->options().relocatable())
    name = Layout::output_section_name(name, &len);

  Stringpool::Key name_key;
  name = this->namepool_.add_with_length(name, len, true, &name_key);

  // Find or make the output section.  The output section is selected
  // based on the section name, type, and flags.
  return this->get_output_section(name, name_key, type, flags);
}

// Return the output section to use for input section SHNDX, with name
// NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
// index of a relocation section which applies to this section, or 0
// if none, or -1U if more than one.  RELOC_TYPE is the type of the
// relocation section if there is one.  Set *OFF to the offset of this
// input section without the output section.  Return NULL if the
// section should be discarded.  Set *OFF to -1 if the section
// contents should not be written directly to the output file, but
// will instead receive special handling.

template<int size, bool big_endian>
Output_section*
Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
	       const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
	       unsigned int reloc_shndx, unsigned int, off_t* off)
{
  if (!this->include_section(object, name, shdr))
    return NULL;

  Output_section* os;

  // In a relocatable link a grouped section must not be combined with
  // any other sections.
  if (parameters->options().relocatable()
      && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
    {
      name = this->namepool_.add(name, true, NULL);
      os = this->make_output_section(name, shdr.get_sh_type(),
				     shdr.get_sh_flags());
    }
  else
    {
      os = this->choose_output_section(object, name, shdr.get_sh_type(),
				       shdr.get_sh_flags(), true);
      if (os == NULL)
	return NULL;
    }

  // By default the GNU linker sorts input sections whose names match
  // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*.  The sections
  // are sorted by name.  This is used to implement constructor
  // priority ordering.  We are compatible.
  if (!this->script_options_->saw_sections_clause()
      && (is_prefix_of(".ctors.", name)
	  || is_prefix_of(".dtors.", name)
	  || is_prefix_of(".init_array.", name)
	  || is_prefix_of(".fini_array.", name)))
    os->set_must_sort_attached_input_sections();

  // FIXME: Handle SHF_LINK_ORDER somewhere.

  *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
			       this->script_options_->saw_sections_clause());

  return os;
}

// Handle a relocation section when doing a relocatable link.

template<int size, bool big_endian>
Output_section*
Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
		     unsigned int,
		     const elfcpp::Shdr<size, big_endian>& shdr,
		     Output_section* data_section,
		     Relocatable_relocs* rr)
{
  gold_assert(parameters->options().relocatable()
	      || parameters->options().emit_relocs());

  int sh_type = shdr.get_sh_type();

  std::string name;
  if (sh_type == elfcpp::SHT_REL)
    name = ".rel";
  else if (sh_type == elfcpp::SHT_RELA)
    name = ".rela";
  else
    gold_unreachable();
  name += data_section->name();

  Output_section* os = this->choose_output_section(object, name.c_str(),
						   sh_type,
						   shdr.get_sh_flags(),
						   false);

  os->set_should_link_to_symtab();
  os->set_info_section(data_section);

  Output_section_data* posd;
  if (sh_type == elfcpp::SHT_REL)
    {
      os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
      posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
					   size,
					   big_endian>(rr);
    }
  else if (sh_type == elfcpp::SHT_RELA)
    {
      os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
      posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
					   size,
					   big_endian>(rr);
    }
  else
    gold_unreachable();

  os->add_output_section_data(posd);
  rr->set_output_data(posd);

  return os;
}

// Handle a group section when doing a relocatable link.

template<int size, bool big_endian>
void
Layout::layout_group(Symbol_table* symtab,
		     Sized_relobj<size, big_endian>* object,
		     unsigned int,
		     const char* group_section_name,
		     const char* signature,
		     const elfcpp::Shdr<size, big_endian>& shdr,
		     const elfcpp::Elf_Word* contents)
{
  gold_assert(parameters->options().relocatable());
  gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
  group_section_name = this->namepool_.add(group_section_name, true, NULL);
  Output_section* os = this->make_output_section(group_section_name,
						 elfcpp::SHT_GROUP,
						 shdr.get_sh_flags());

  // We need to find a symbol with the signature in the symbol table.
  // If we don't find one now, we need to look again later.
  Symbol* sym = symtab->lookup(signature, NULL);
  if (sym != NULL)
    os->set_info_symndx(sym);
  else
    {
      // We will wind up using a symbol whose name is the signature.
      // So just put the signature in the symbol name pool to save it.
      signature = symtab->canonicalize_name(signature);
      this->group_signatures_.push_back(Group_signature(os, signature));
    }

  os->set_should_link_to_symtab();
  os->set_entsize(4);

  section_size_type entry_count =
    convert_to_section_size_type(shdr.get_sh_size() / 4);
  Output_section_data* posd =
    new Output_data_group<size, big_endian>(object, entry_count, contents);
  os->add_output_section_data(posd);
}

// Special GNU handling of sections name .eh_frame.  They will
// normally hold exception frame data as defined by the C++ ABI
// (http://codesourcery.com/cxx-abi/).

template<int size, bool big_endian>
Output_section*
Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
			const unsigned char* symbols,
			off_t symbols_size,
			const unsigned char* symbol_names,
			off_t symbol_names_size,
			unsigned int shndx,
			const elfcpp::Shdr<size, big_endian>& shdr,
			unsigned int reloc_shndx, unsigned int reloc_type,
			off_t* off)
{
  gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
  gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);

  const char* const name = ".eh_frame";
  Output_section* os = this->choose_output_section(object,
						   name,
						   elfcpp::SHT_PROGBITS,
						   elfcpp::SHF_ALLOC,
						   false);
  if (os == NULL)
    return NULL;

  if (this->eh_frame_section_ == NULL)
    {
      this->eh_frame_section_ = os;
      this->eh_frame_data_ = new Eh_frame();

      if (this->options_.eh_frame_hdr())
	{
	  Output_section* hdr_os =
	    this->choose_output_section(NULL,
					".eh_frame_hdr",
					elfcpp::SHT_PROGBITS,
					elfcpp::SHF_ALLOC,
					false);

	  if (hdr_os != NULL)
	    {
	      Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
							this->eh_frame_data_);
	      hdr_os->add_output_section_data(hdr_posd);

	      hdr_os->set_after_input_sections();

	      if (!this->script_options_->saw_phdrs_clause())
		{
		  Output_segment* hdr_oseg;
		  hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
						       elfcpp::PF_R);
		  hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
		}

	      this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
	    }
	}
    }

  gold_assert(this->eh_frame_section_ == os);

  if (this->eh_frame_data_->add_ehframe_input_section(object,
						      symbols,
						      symbols_size,
						      symbol_names,
						      symbol_names_size,
						      shndx,
						      reloc_shndx,
						      reloc_type))
    {
      os->update_flags_for_input_section(shdr.get_sh_flags());

      // We found a .eh_frame section we are going to optimize, so now
      // we can add the set of optimized sections to the output
      // section.  We need to postpone adding this until we've found a
      // section we can optimize so that the .eh_frame section in
      // crtbegin.o winds up at the start of the output section.
      if (!this->added_eh_frame_data_)
	{
	  os->add_output_section_data(this->eh_frame_data_);
	  this->added_eh_frame_data_ = true;
	}
      *off = -1;
    }
  else
    {
      // We couldn't handle this .eh_frame section for some reason.
      // Add it as a normal section.
      bool saw_sections_clause = this->script_options_->saw_sections_clause();
      *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
				   saw_sections_clause);
    }

  return os;
}

// Add POSD to an output section using NAME, TYPE, and FLAGS.

void
Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
				elfcpp::Elf_Xword flags,
				Output_section_data* posd)
{
  Output_section* os = this->choose_output_section(NULL, name, type, flags,
						   false);
  if (os != NULL)
    os->add_output_section_data(posd);
}

// Map section flags to segment flags.

elfcpp::Elf_Word
Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
{
  elfcpp::Elf_Word ret = elfcpp::PF_R;
  if ((flags & elfcpp::SHF_WRITE) != 0)
    ret |= elfcpp::PF_W;
  if ((flags & elfcpp::SHF_EXECINSTR) != 0)
    ret |= elfcpp::PF_X;
  return ret;
}

// Sometimes we compress sections.  This is typically done for
// sections that are not part of normal program execution (such as
// .debug_* sections), and where the readers of these sections know
// how to deal with compressed sections.  (To make it easier for them,
// we will rename the ouput section in such cases from .foo to
// .foo.zlib.nnnn, where nnnn is the uncompressed size.)  This routine
// doesn't say for certain whether we'll compress -- it depends on
// commandline options as well -- just whether this section is a
// candidate for compression.

static bool
is_compressible_debug_section(const char* secname)
{
  return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
}

// Make a new Output_section, and attach it to segments as
// appropriate.

Output_section*
Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
			    elfcpp::Elf_Xword flags)
{
  Output_section* os;
  if ((flags & elfcpp::SHF_ALLOC) == 0
      && strcmp(this->options_.compress_debug_sections(), "none") != 0
      && is_compressible_debug_section(name))
    os = new Output_compressed_section(&this->options_, name, type, flags);
  else
    os = new Output_section(name, type, flags);

  this->section_list_.push_back(os);

  // The GNU linker by default sorts some sections by priority, so we
  // do the same.  We need to know that this might happen before we
  // attach any input sections.
  if (!this->script_options_->saw_sections_clause()
      && (strcmp(name, ".ctors") == 0
	  || strcmp(name, ".dtors") == 0
	  || strcmp(name, ".init_array") == 0
	  || strcmp(name, ".fini_array") == 0))
    os->set_may_sort_attached_input_sections();

  // If we have already attached the sections to segments, then we
  // need to attach this one now.  This happens for sections created
  // directly by the linker.
  if (this->sections_are_attached_)
    this->attach_section_to_segment(os);

  return os;
}

// Attach output sections to segments.  This is called after we have
// seen all the input sections.

void
Layout::attach_sections_to_segments()
{
  for (Section_list::iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    this->attach_section_to_segment(*p);

  this->sections_are_attached_ = true;
}

// Attach an output section to a segment.

void
Layout::attach_section_to_segment(Output_section* os)
{
  if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
    this->unattached_section_list_.push_back(os);
  else
    this->attach_allocated_section_to_segment(os);
}

// Attach an allocated output section to a segment.

void
Layout::attach_allocated_section_to_segment(Output_section* os)
{
  elfcpp::Elf_Xword flags = os->flags();
  gold_assert((flags & elfcpp::SHF_ALLOC) != 0);

  if (parameters->options().relocatable())
    return;

  // If we have a SECTIONS clause, we can't handle the attachment to
  // segments until after we've seen all the sections.
  if (this->script_options_->saw_sections_clause())
    return;

  gold_assert(!this->script_options_->saw_phdrs_clause());

  // This output section goes into a PT_LOAD segment.

  elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);

  // In general the only thing we really care about for PT_LOAD
  // segments is whether or not they are writable, so that is how we
  // search for them.  People who need segments sorted on some other
  // basis will have to use a linker script.

  Segment_list::const_iterator p;
  for (p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() == elfcpp::PT_LOAD
          && ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
        {
          // If -Tbss was specified, we need to separate the data
          // and BSS segments.
          if (this->options_.user_set_Tbss())
            {
              if ((os->type() == elfcpp::SHT_NOBITS)
                  == (*p)->has_any_data_sections())
                continue;
            }

          (*p)->add_output_section(os, seg_flags);
          break;
        }
    }

  if (p == this->segment_list_.end())
    {
      Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
                                                       seg_flags);
      oseg->add_output_section(os, seg_flags);
    }

  // If we see a loadable SHT_NOTE section, we create a PT_NOTE
  // segment.
  if (os->type() == elfcpp::SHT_NOTE)
    {
      // See if we already have an equivalent PT_NOTE segment.
      for (p = this->segment_list_.begin();
           p != segment_list_.end();
           ++p)
        {
          if ((*p)->type() == elfcpp::PT_NOTE
              && (((*p)->flags() & elfcpp::PF_W)
                  == (seg_flags & elfcpp::PF_W)))
            {
              (*p)->add_output_section(os, seg_flags);
              break;
            }
        }

      if (p == this->segment_list_.end())
        {
          Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
                                                           seg_flags);
          oseg->add_output_section(os, seg_flags);
        }
    }

  // If we see a loadable SHF_TLS section, we create a PT_TLS
  // segment.  There can only be one such segment.
  if ((flags & elfcpp::SHF_TLS) != 0)
    {
      if (this->tls_segment_ == NULL)
        this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS,
                                                       seg_flags);
      this->tls_segment_->add_output_section(os, seg_flags);
    }
}

// Make an output section for a script.

Output_section*
Layout::make_output_section_for_script(const char* name)
{
  name = this->namepool_.add(name, false, NULL);
  Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
						 elfcpp::SHF_ALLOC);
  os->set_found_in_sections_clause();
  return os;
}

// Return the number of segments we expect to see.

size_t
Layout::expected_segment_count() const
{
  size_t ret = this->segment_list_.size();

  // If we didn't see a SECTIONS clause in a linker script, we should
  // already have the complete list of segments.  Otherwise we ask the
  // SECTIONS clause how many segments it expects, and add in the ones
  // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)

  if (!this->script_options_->saw_sections_clause())
    return ret;
  else
    {
      const Script_sections* ss = this->script_options_->script_sections();
      return ret + ss->expected_segment_count(this);
    }
}

// Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
// is whether we saw a .note.GNU-stack section in the object file.
// GNU_STACK_FLAGS is the section flags.  The flags give the
// protection required for stack memory.  We record this in an
// executable as a PT_GNU_STACK segment.  If an object file does not
// have a .note.GNU-stack segment, we must assume that it is an old
// object.  On some targets that will force an executable stack.

void
Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
{
  if (!seen_gnu_stack)
    this->input_without_gnu_stack_note_ = true;
  else
    {
      this->input_with_gnu_stack_note_ = true;
      if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
	this->input_requires_executable_stack_ = true;
    }
}

// Create the dynamic sections which are needed before we read the
// relocs.

void
Layout::create_initial_dynamic_sections(Symbol_table* symtab)
{
  if (parameters->doing_static_link())
    return;

  this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
						       elfcpp::SHT_DYNAMIC,
						       (elfcpp::SHF_ALLOC
							| elfcpp::SHF_WRITE),
						       false);

  symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
				elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
				elfcpp::STV_HIDDEN, 0, false, false);

  this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);

  this->dynamic_section_->add_output_section_data(this->dynamic_data_);
}

// For each output section whose name can be represented as C symbol,
// define __start and __stop symbols for the section.  This is a GNU
// extension.

void
Layout::define_section_symbols(Symbol_table* symtab)
{
  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      const char* const name = (*p)->name();
      if (name[strspn(name,
		      ("0123456789"
		       "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
		       "abcdefghijklmnopqrstuvwxyz"
		       "_"))]
	  == '\0')
	{
	  const std::string name_string(name);
	  const std::string start_name("__start_" + name_string);
	  const std::string stop_name("__stop_" + name_string);

	  symtab->define_in_output_data(start_name.c_str(),
					NULL, // version
					*p,
					0, // value
					0, // symsize
					elfcpp::STT_NOTYPE,
					elfcpp::STB_GLOBAL,
					elfcpp::STV_DEFAULT,
					0, // nonvis
					false, // offset_is_from_end
					true); // only_if_ref

	  symtab->define_in_output_data(stop_name.c_str(),
					NULL, // version
					*p,
					0, // value
					0, // symsize
					elfcpp::STT_NOTYPE,
					elfcpp::STB_GLOBAL,
					elfcpp::STV_DEFAULT,
					0, // nonvis
					true, // offset_is_from_end
					true); // only_if_ref
	}
    }
}

// Define symbols for group signatures.

void
Layout::define_group_signatures(Symbol_table* symtab)
{
  for (Group_signatures::iterator p = this->group_signatures_.begin();
       p != this->group_signatures_.end();
       ++p)
    {
      Symbol* sym = symtab->lookup(p->signature, NULL);
      if (sym != NULL)
	p->section->set_info_symndx(sym);
      else
	{
	  // Force the name of the group section to the group
	  // signature, and use the group's section symbol as the
	  // signature symbol.
	  if (strcmp(p->section->name(), p->signature) != 0)
	    {
	      const char* name = this->namepool_.add(p->signature,
						     true, NULL);
	      p->section->set_name(name);
	    }
	  p->section->set_needs_symtab_index();
	  p->section->set_info_section_symndx(p->section);
	}
    }

  this->group_signatures_.clear();
}

// Find the first read-only PT_LOAD segment, creating one if
// necessary.

Output_segment*
Layout::find_first_load_seg()
{
  for (Segment_list::const_iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() == elfcpp::PT_LOAD
	  && ((*p)->flags() & elfcpp::PF_R) != 0
	  && ((*p)->flags() & elfcpp::PF_W) == 0)
	return *p;
    }

  gold_assert(!this->script_options_->saw_phdrs_clause());

  Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
						       elfcpp::PF_R);
  return load_seg;
}

// Finalize the layout.  When this is called, we have created all the
// output sections and all the output segments which are based on
// input sections.  We have several things to do, and we have to do
// them in the right order, so that we get the right results correctly
// and efficiently.

// 1) Finalize the list of output segments and create the segment
// table header.

// 2) Finalize the dynamic symbol table and associated sections.

// 3) Determine the final file offset of all the output segments.

// 4) Determine the final file offset of all the SHF_ALLOC output
// sections.

// 5) Create the symbol table sections and the section name table
// section.

// 6) Finalize the symbol table: set symbol values to their final
// value and make a final determination of which symbols are going
// into the output symbol table.

// 7) Create the section table header.

// 8) Determine the final file offset of all the output sections which
// are not SHF_ALLOC, including the section table header.

// 9) Finalize the ELF file header.

// This function returns the size of the output file.

off_t
Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
		 Target* target, const Task* task)
{
  target->finalize_sections(this);

  this->count_local_symbols(task, input_objects);

  this->create_gold_note();
  this->create_executable_stack_info(target);
  this->create_build_id();

  Output_segment* phdr_seg = NULL;
  if (!parameters->options().relocatable() && !parameters->doing_static_link())
    {
      // There was a dynamic object in the link.  We need to create
      // some information for the dynamic linker.

      // Create the PT_PHDR segment which will hold the program
      // headers.
      if (!this->script_options_->saw_phdrs_clause())
	phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);

      // Create the dynamic symbol table, including the hash table.
      Output_section* dynstr;
      std::vector<Symbol*> dynamic_symbols;
      unsigned int local_dynamic_count;
      Versions versions(*this->script_options()->version_script_info(),
                        &this->dynpool_);
      this->create_dynamic_symtab(input_objects, symtab, &dynstr,
				  &local_dynamic_count, &dynamic_symbols,
				  &versions);

      // Create the .interp section to hold the name of the
      // interpreter, and put it in a PT_INTERP segment.
      if (!parameters->options().shared())
        this->create_interp(target);

      // Finish the .dynamic section to hold the dynamic data, and put
      // it in a PT_DYNAMIC segment.
      this->finish_dynamic_section(input_objects, symtab);

      // We should have added everything we need to the dynamic string
      // table.
      this->dynpool_.set_string_offsets();

      // Create the version sections.  We can't do this until the
      // dynamic string table is complete.
      this->create_version_sections(&versions, symtab, local_dynamic_count,
				    dynamic_symbols, dynstr);
    }

  // If there is a SECTIONS clause, put all the input sections into
  // the required order.
  Output_segment* load_seg;
  if (this->script_options_->saw_sections_clause())
    load_seg = this->set_section_addresses_from_script(symtab);
  else if (parameters->options().relocatable())
    load_seg = NULL;
  else
    load_seg = this->find_first_load_seg();

  if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
    load_seg = NULL;

  gold_assert(phdr_seg == NULL || load_seg != NULL);

  // Lay out the segment headers.
  Output_segment_headers* segment_headers;
  if (parameters->options().relocatable())
    segment_headers = NULL;
  else
    {
      segment_headers = new Output_segment_headers(this->segment_list_);
      if (load_seg != NULL)
	load_seg->add_initial_output_data(segment_headers);
      if (phdr_seg != NULL)
	phdr_seg->add_initial_output_data(segment_headers);
    }

  // Lay out the file header.
  Output_file_header* file_header;
  file_header = new Output_file_header(target, symtab, segment_headers,
				       this->options_.entry());
  if (load_seg != NULL)
    load_seg->add_initial_output_data(file_header);

  this->special_output_list_.push_back(file_header);
  if (segment_headers != NULL)
    this->special_output_list_.push_back(segment_headers);

  if (this->script_options_->saw_phdrs_clause()
      && !parameters->options().relocatable())
    {
      // Support use of FILEHDRS and PHDRS attachments in a PHDRS
      // clause in a linker script.
      Script_sections* ss = this->script_options_->script_sections();
      ss->put_headers_in_phdrs(file_header, segment_headers);
    }

  // We set the output section indexes in set_segment_offsets and
  // set_section_indexes.
  unsigned int shndx = 1;

  // Set the file offsets of all the segments, and all the sections
  // they contain.
  off_t off;
  if (!parameters->options().relocatable())
    off = this->set_segment_offsets(target, load_seg, &shndx);
  else
    off = this->set_relocatable_section_offsets(file_header, &shndx);

  // Set the file offsets of all the non-data sections we've seen so
  // far which don't have to wait for the input sections.  We need
  // this in order to finalize local symbols in non-allocated
  // sections.
  off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);

  // Create the symbol table sections.
  this->create_symtab_sections(input_objects, symtab, &off);
  if (!parameters->doing_static_link())
    this->assign_local_dynsym_offsets(input_objects);

  // Process any symbol assignments from a linker script.  This must
  // be called after the symbol table has been finalized.
  this->script_options_->finalize_symbols(symtab, this);

  // Create the .shstrtab section.
  Output_section* shstrtab_section = this->create_shstrtab();

  // Set the file offsets of the rest of the non-data sections which
  // don't have to wait for the input sections.
  off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);

  // Now that all sections have been created, set the section indexes.
  shndx = this->set_section_indexes(shndx);

  // Create the section table header.
  this->create_shdrs(&off);

  // If there are no sections which require postprocessing, we can
  // handle the section names now, and avoid a resize later.
  if (!this->any_postprocessing_sections_)
    off = this->set_section_offsets(off,
				    STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);

  file_header->set_section_info(this->section_headers_, shstrtab_section);

  // Now we know exactly where everything goes in the output file
  // (except for non-allocated sections which require postprocessing).
  Output_data::layout_complete();

  this->output_file_size_ = off;

  return off;
}

// Create a note header following the format defined in the ELF ABI.
// NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the
// descriptor.  ALLOCATE is true if the section should be allocated in
// memory.  This returns the new note section.  It sets
// *TRAILING_PADDING to the number of trailing zero bytes required.

Output_section*
Layout::create_note(const char* name, int note_type, size_t descsz,
		    bool allocate, size_t* trailing_padding)
{
  // Authorities all agree that the values in a .note field should
  // be aligned on 4-byte boundaries for 32-bit binaries.  However,
  // they differ on what the alignment is for 64-bit binaries.
  // The GABI says unambiguously they take 8-byte alignment:
  //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
  // Other documentation says alignment should always be 4 bytes:
  //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
  // GNU ld and GNU readelf both support the latter (at least as of
  // version 2.16.91), and glibc always generates the latter for
  // .note.ABI-tag (as of version 1.6), so that's the one we go with
  // here.
#ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
  const int size = parameters->target().get_size();
#else
  const int size = 32;
#endif

  // The contents of the .note section.
  size_t namesz = strlen(name) + 1;
  size_t aligned_namesz = align_address(namesz, size / 8);
  size_t aligned_descsz = align_address(descsz, size / 8);

  size_t notehdrsz = 3 * (size / 8) + aligned_namesz;

  unsigned char* buffer = new unsigned char[notehdrsz];
  memset(buffer, 0, notehdrsz);

  bool is_big_endian = parameters->target().is_big_endian();

  if (size == 32)
    {
      if (!is_big_endian)
	{
	  elfcpp::Swap<32, false>::writeval(buffer, namesz);
	  elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
	  elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
	}
      else
	{
	  elfcpp::Swap<32, true>::writeval(buffer, namesz);
	  elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
	  elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
	}
    }
  else if (size == 64)
    {
      if (!is_big_endian)
	{
	  elfcpp::Swap<64, false>::writeval(buffer, namesz);
	  elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
	  elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
	}
      else
	{
	  elfcpp::Swap<64, true>::writeval(buffer, namesz);
	  elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
	  elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
	}
    }
  else
    gold_unreachable();

  memcpy(buffer + 3 * (size / 8), name, namesz);

  const char* note_name = this->namepool_.add(".note", false, NULL);
  elfcpp::Elf_Xword flags = 0;
  if (allocate)
    flags = elfcpp::SHF_ALLOC;
  Output_section* os = this->make_output_section(note_name,
						 elfcpp::SHT_NOTE,
						 flags);
  Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
							   size / 8);
  os->add_output_section_data(posd);

  *trailing_padding = aligned_descsz - descsz;

  return os;
}

// For an executable or shared library, create a note to record the
// version of gold used to create the binary.

void
Layout::create_gold_note()
{
  if (parameters->options().relocatable())
    return;

  std::string desc = std::string("gold ") + gold::get_version_string();

  size_t trailing_padding;
  Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
					 desc.size(), false, &trailing_padding);

  Output_section_data* posd = new Output_data_const(desc, 4);
  os->add_output_section_data(posd);

  if (trailing_padding > 0)
    {
      posd = new Output_data_fixed_space(trailing_padding, 0);
      os->add_output_section_data(posd);
    }
}

// Record whether the stack should be executable.  This can be set
// from the command line using the -z execstack or -z noexecstack
// options.  Otherwise, if any input file has a .note.GNU-stack
// section with the SHF_EXECINSTR flag set, the stack should be
// executable.  Otherwise, if at least one input file a
// .note.GNU-stack section, and some input file has no .note.GNU-stack
// section, we use the target default for whether the stack should be
// executable.  Otherwise, we don't generate a stack note.  When
// generating a object file, we create a .note.GNU-stack section with
// the appropriate marking.  When generating an executable or shared
// library, we create a PT_GNU_STACK segment.

void
Layout::create_executable_stack_info(const Target* target)
{
  bool is_stack_executable;
  if (this->options_.is_execstack_set())
    is_stack_executable = this->options_.is_stack_executable();
  else if (!this->input_with_gnu_stack_note_)
    return;
  else
    {
      if (this->input_requires_executable_stack_)
	is_stack_executable = true;
      else if (this->input_without_gnu_stack_note_)
	is_stack_executable = target->is_default_stack_executable();
      else
	is_stack_executable = false;
    }

  if (parameters->options().relocatable())
    {
      const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
      elfcpp::Elf_Xword flags = 0;
      if (is_stack_executable)
	flags |= elfcpp::SHF_EXECINSTR;
      this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
    }
  else
    {
      if (this->script_options_->saw_phdrs_clause())
	return;
      int flags = elfcpp::PF_R | elfcpp::PF_W;
      if (is_stack_executable)
	flags |= elfcpp::PF_X;
      this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
    }
}

// If --build-id was used, set up the build ID note.

void
Layout::create_build_id()
{
  if (!parameters->options().user_set_build_id())
    return;

  const char* style = parameters->options().build_id();
  if (strcmp(style, "none") == 0)
    return;

  // Set DESCSZ to the size of the note descriptor.  When possible,
  // set DESC to the note descriptor contents.
  size_t descsz;
  std::string desc;
  if (strcmp(style, "md5") == 0)
    descsz = 128 / 8;
  else if (strcmp(style, "sha1") == 0)
    descsz = 160 / 8;
  else if (strcmp(style, "uuid") == 0)
    {
      const size_t uuidsz = 128 / 8;

      char buffer[uuidsz];
      memset(buffer, 0, uuidsz);

      int descriptor = ::open("/dev/urandom", O_RDONLY);
      if (descriptor < 0)
	gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
		   strerror(errno));
      else
	{
	  ssize_t got = ::read(descriptor, buffer, uuidsz);
	  ::close(descriptor);
	  if (got < 0)
	    gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
	  else if (static_cast<size_t>(got) != uuidsz)
	    gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
		       uuidsz, got);
	}

      desc.assign(buffer, uuidsz);
      descsz = uuidsz;
    }
  else if (strncmp(style, "0x", 2) == 0)
    {
      hex_init();
      const char* p = style + 2;
      while (*p != '\0')
	{
	  if (hex_p(p[0]) && hex_p(p[1]))
	    {
	      char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
	      desc += c;
	      p += 2;
	    }
	  else if (*p == '-' || *p == ':')
	    ++p;
	  else
	    gold_fatal(_("--build-id argument '%s' not a valid hex number"),
		       style);
	}
      descsz = desc.size();
    }
  else
    gold_fatal(_("unrecognized --build-id argument '%s'"), style);

  // Create the note.
  size_t trailing_padding;
  Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
					 descsz, true, &trailing_padding);

  if (!desc.empty())
    {
      // We know the value already, so we fill it in now.
      gold_assert(desc.size() == descsz);

      Output_section_data* posd = new Output_data_const(desc, 4);
      os->add_output_section_data(posd);

      if (trailing_padding != 0)
	{
	  posd = new Output_data_fixed_space(trailing_padding, 0);
	  os->add_output_section_data(posd);
	}
    }
  else
    {
      // We need to compute a checksum after we have completed the
      // link.
      gold_assert(trailing_padding == 0);
      this->build_id_note_ = new Output_data_fixed_space(descsz, 4);
      os->add_output_section_data(this->build_id_note_);
      os->set_after_input_sections();
    }
}

// Return whether SEG1 should be before SEG2 in the output file.  This
// is based entirely on the segment type and flags.  When this is
// called the segment addresses has normally not yet been set.

bool
Layout::segment_precedes(const Output_segment* seg1,
			 const Output_segment* seg2)
{
  elfcpp::Elf_Word type1 = seg1->type();
  elfcpp::Elf_Word type2 = seg2->type();

  // The single PT_PHDR segment is required to precede any loadable
  // segment.  We simply make it always first.
  if (type1 == elfcpp::PT_PHDR)
    {
      gold_assert(type2 != elfcpp::PT_PHDR);
      return true;
    }
  if (type2 == elfcpp::PT_PHDR)
    return false;

  // The single PT_INTERP segment is required to precede any loadable
  // segment.  We simply make it always second.
  if (type1 == elfcpp::PT_INTERP)
    {
      gold_assert(type2 != elfcpp::PT_INTERP);
      return true;
    }
  if (type2 == elfcpp::PT_INTERP)
    return false;

  // We then put PT_LOAD segments before any other segments.
  if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
    return true;
  if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
    return false;

  // We put the PT_TLS segment last, because that is where the dynamic
  // linker expects to find it (this is just for efficiency; other
  // positions would also work correctly).
  if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
    return false;
  if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
    return true;

  const elfcpp::Elf_Word flags1 = seg1->flags();
  const elfcpp::Elf_Word flags2 = seg2->flags();

  // The order of non-PT_LOAD segments is unimportant.  We simply sort
  // by the numeric segment type and flags values.  There should not
  // be more than one segment with the same type and flags.
  if (type1 != elfcpp::PT_LOAD)
    {
      if (type1 != type2)
	return type1 < type2;
      gold_assert(flags1 != flags2);
      return flags1 < flags2;
    }

  // If the addresses are set already, sort by load address.
  if (seg1->are_addresses_set())
    {
      if (!seg2->are_addresses_set())
	return true;

      unsigned int section_count1 = seg1->output_section_count();
      unsigned int section_count2 = seg2->output_section_count();
      if (section_count1 == 0 && section_count2 > 0)
	return true;
      if (section_count1 > 0 && section_count2 == 0)
	return false;

      uint64_t paddr1 = seg1->first_section_load_address();
      uint64_t paddr2 = seg2->first_section_load_address();
      if (paddr1 != paddr2)
	return paddr1 < paddr2;
    }
  else if (seg2->are_addresses_set())
    return false;

  // We sort PT_LOAD segments based on the flags.  Readonly segments
  // come before writable segments.  Then writable segments with data
  // come before writable segments without data.  Then executable
  // segments come before non-executable segments.  Then the unlikely
  // case of a non-readable segment comes before the normal case of a
  // readable segment.  If there are multiple segments with the same
  // type and flags, we require that the address be set, and we sort
  // by virtual address and then physical address.
  if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
    return (flags1 & elfcpp::PF_W) == 0;
  if ((flags1 & elfcpp::PF_W) != 0
      && seg1->has_any_data_sections() != seg2->has_any_data_sections())
    return seg1->has_any_data_sections();
  if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
    return (flags1 & elfcpp::PF_X) != 0;
  if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
    return (flags1 & elfcpp::PF_R) == 0;

  // We shouldn't get here--we shouldn't create segments which we
  // can't distinguish.
  gold_unreachable();
}

// Set the file offsets of all the segments, and all the sections they
// contain.  They have all been created.  LOAD_SEG must be be laid out
// first.  Return the offset of the data to follow.

off_t
Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
			    unsigned int *pshndx)
{
  // Sort them into the final order.
  std::sort(this->segment_list_.begin(), this->segment_list_.end(),
	    Layout::Compare_segments());

  // Find the PT_LOAD segments, and set their addresses and offsets
  // and their section's addresses and offsets.
  uint64_t addr;
  if (this->options_.user_set_Ttext())
    addr = this->options_.Ttext();
  else if (parameters->options().shared())
    addr = 0;
  else
    addr = target->default_text_segment_address();
  off_t off = 0;

  // If LOAD_SEG is NULL, then the file header and segment headers
  // will not be loadable.  But they still need to be at offset 0 in
  // the file.  Set their offsets now.
  if (load_seg == NULL)
    {
      for (Data_list::iterator p = this->special_output_list_.begin();
	   p != this->special_output_list_.end();
	   ++p)
	{
	  off = align_address(off, (*p)->addralign());
	  (*p)->set_address_and_file_offset(0, off);
	  off += (*p)->data_size();
	}
    }

  bool was_readonly = false;
  for (Segment_list::iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() == elfcpp::PT_LOAD)
	{
	  if (load_seg != NULL && load_seg != *p)
	    gold_unreachable();
	  load_seg = NULL;

	  bool are_addresses_set = (*p)->are_addresses_set();
	  if (are_addresses_set)
	    {
	      // When it comes to setting file offsets, we care about
	      // the physical address.
	      addr = (*p)->paddr();
	    }
	  else if (this->options_.user_set_Tdata()
		   && ((*p)->flags() & elfcpp::PF_W) != 0
		   && (!this->options_.user_set_Tbss()
		       || (*p)->has_any_data_sections()))
	    {
	      addr = this->options_.Tdata();
	      are_addresses_set = true;
	    }
	  else if (this->options_.user_set_Tbss()
		   && ((*p)->flags() & elfcpp::PF_W) != 0
		   && !(*p)->has_any_data_sections())
	    {
	      addr = this->options_.Tbss();
	      are_addresses_set = true;
	    }

	  uint64_t orig_addr = addr;
	  uint64_t orig_off = off;

	  uint64_t aligned_addr = 0;
	  uint64_t abi_pagesize = target->abi_pagesize();

	  // FIXME: This should depend on the -n and -N options.
	  (*p)->set_minimum_p_align(target->common_pagesize());

	  if (are_addresses_set)
	    {
	      // Adjust the file offset to the same address modulo the
	      // page size.
	      uint64_t unsigned_off = off;
	      uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
				      | (addr & (abi_pagesize - 1)));
	      if (aligned_off < unsigned_off)
		aligned_off += abi_pagesize;
	      off = aligned_off;
	    }
	  else
	    {
	      // If the last segment was readonly, and this one is
	      // not, then skip the address forward one page,
	      // maintaining the same position within the page.  This
	      // lets us store both segments overlapping on a single
	      // page in the file, but the loader will put them on
	      // different pages in memory.

	      addr = align_address(addr, (*p)->maximum_alignment());
	      aligned_addr = addr;

	      if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
		{
		  if ((addr & (abi_pagesize - 1)) != 0)
		    addr = addr + abi_pagesize;
		}

	      off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
	    }

	  unsigned int shndx_hold = *pshndx;
	  uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
                                                          &off, pshndx);

	  // Now that we know the size of this segment, we may be able
	  // to save a page in memory, at the cost of wasting some
	  // file space, by instead aligning to the start of a new
	  // page.  Here we use the real machine page size rather than
	  // the ABI mandated page size.

	  if (!are_addresses_set && aligned_addr != addr)
	    {
	      uint64_t common_pagesize = target->common_pagesize();
	      uint64_t first_off = (common_pagesize
				    - (aligned_addr
				       & (common_pagesize - 1)));
	      uint64_t last_off = new_addr & (common_pagesize - 1);
	      if (first_off > 0
		  && last_off > 0
		  && ((aligned_addr & ~ (common_pagesize - 1))
		      != (new_addr & ~ (common_pagesize - 1)))
		  && first_off + last_off <= common_pagesize)
		{
		  *pshndx = shndx_hold;
		  addr = align_address(aligned_addr, common_pagesize);
		  addr = align_address(addr, (*p)->maximum_alignment());
		  off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
		  new_addr = (*p)->set_section_addresses(this, true, addr,
                                                         &off, pshndx);
		}
	    }

	  addr = new_addr;

	  if (((*p)->flags() & elfcpp::PF_W) == 0)
	    was_readonly = true;
	}
    }

  // Handle the non-PT_LOAD segments, setting their offsets from their
  // section's offsets.
  for (Segment_list::iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() != elfcpp::PT_LOAD)
	(*p)->set_offset();
    }

  // Set the TLS offsets for each section in the PT_TLS segment.
  if (this->tls_segment_ != NULL)
    this->tls_segment_->set_tls_offsets();

  return off;
}

// Set the offsets of all the allocated sections when doing a
// relocatable link.  This does the same jobs as set_segment_offsets,
// only for a relocatable link.

off_t
Layout::set_relocatable_section_offsets(Output_data* file_header,
					unsigned int *pshndx)
{
  off_t off = 0;

  file_header->set_address_and_file_offset(0, 0);
  off += file_header->data_size();

  for (Section_list::iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      // We skip unallocated sections here, except that group sections
      // have to come first.
      if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
	  && (*p)->type() != elfcpp::SHT_GROUP)
	continue;

      off = align_address(off, (*p)->addralign());

      // The linker script might have set the address.
      if (!(*p)->is_address_valid())
	(*p)->set_address(0);
      (*p)->set_file_offset(off);
      (*p)->finalize_data_size();
      off += (*p)->data_size();

      (*p)->set_out_shndx(*pshndx);
      ++*pshndx;
    }

  return off;
}

// Set the file offset of all the sections not associated with a
// segment.

off_t
Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
{
  for (Section_list::iterator p = this->unattached_section_list_.begin();
       p != this->unattached_section_list_.end();
       ++p)
    {
      // The symtab section is handled in create_symtab_sections.
      if (*p == this->symtab_section_)
	continue;

      // If we've already set the data size, don't set it again.
      if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
	continue;

      if (pass == BEFORE_INPUT_SECTIONS_PASS
	  && (*p)->requires_postprocessing())
	{
	  (*p)->create_postprocessing_buffer();
	  this->any_postprocessing_sections_ = true;
	}

      if (pass == BEFORE_INPUT_SECTIONS_PASS
          && (*p)->after_input_sections())
        continue;
      else if (pass == POSTPROCESSING_SECTIONS_PASS
               && (!(*p)->after_input_sections()
                   || (*p)->type() == elfcpp::SHT_STRTAB))
        continue;
      else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
               && (!(*p)->after_input_sections()
                   || (*p)->type() != elfcpp::SHT_STRTAB))
        continue;

      off = align_address(off, (*p)->addralign());
      (*p)->set_file_offset(off);
      (*p)->finalize_data_size();
      off += (*p)->data_size();

      // At this point the name must be set.
      if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
	this->namepool_.add((*p)->name(), false, NULL);
    }
  return off;
}

// Set the section indexes of all the sections not associated with a
// segment.

unsigned int
Layout::set_section_indexes(unsigned int shndx)
{
  const bool output_is_object = parameters->options().relocatable();
  for (Section_list::iterator p = this->unattached_section_list_.begin();
       p != this->unattached_section_list_.end();
       ++p)
    {
      // In a relocatable link, we already did group sections.
      if (output_is_object
	  && (*p)->type() == elfcpp::SHT_GROUP)
	continue;

      (*p)->set_out_shndx(shndx);
      ++shndx;
    }
  return shndx;
}

// Set the section addresses according to the linker script.  This is
// only called when we see a SECTIONS clause.  This returns the
// program segment which should hold the file header and segment
// headers, if any.  It will return NULL if they should not be in a
// segment.

Output_segment*
Layout::set_section_addresses_from_script(Symbol_table* symtab)
{
  Script_sections* ss = this->script_options_->script_sections();
  gold_assert(ss->saw_sections_clause());

  // Place each orphaned output section in the script.
  for (Section_list::iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if (!(*p)->found_in_sections_clause())
	ss->place_orphan(*p);
    }

  return this->script_options_->set_section_addresses(symtab, this);
}

// Count the local symbols in the regular symbol table and the dynamic
// symbol table, and build the respective string pools.

void
Layout::count_local_symbols(const Task* task,
			    const Input_objects* input_objects)
{
  // First, figure out an upper bound on the number of symbols we'll
  // be inserting into each pool.  This helps us create the pools with
  // the right size, to avoid unnecessary hashtable resizing.
  unsigned int symbol_count = 0;
  for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
       p != input_objects->relobj_end();
       ++p)
    symbol_count += (*p)->local_symbol_count();

  // Go from "upper bound" to "estimate."  We overcount for two
  // reasons: we double-count symbols that occur in more than one
  // object file, and we count symbols that are dropped from the
  // output.  Add it all together and assume we overcount by 100%.
  symbol_count /= 2;

  // We assume all symbols will go into both the sympool and dynpool.
  this->sympool_.reserve(symbol_count);
  this->dynpool_.reserve(symbol_count);

  for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
       p != input_objects->relobj_end();
       ++p)
    {
      Task_lock_obj<Object> tlo(task, *p);
      (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
    }
}

// Create the symbol table sections.  Here we also set the final
// values of the symbols.  At this point all the loadable sections are
// fully laid out.

void
Layout::create_symtab_sections(const Input_objects* input_objects,
			       Symbol_table* symtab,
			       off_t* poff)
{
  int symsize;
  unsigned int align;
  if (parameters->target().get_size() == 32)
    {
      symsize = elfcpp::Elf_sizes<32>::sym_size;
      align = 4;
    }
  else if (parameters->target().get_size() == 64)
    {
      symsize = elfcpp::Elf_sizes<64>::sym_size;
      align = 8;
    }
  else
    gold_unreachable();

  off_t off = *poff;
  off = align_address(off, align);
  off_t startoff = off;

  // Save space for the dummy symbol at the start of the section.  We
  // never bother to write this out--it will just be left as zero.
  off += symsize;
  unsigned int local_symbol_index = 1;

  // Add STT_SECTION symbols for each Output section which needs one.
  for (Section_list::iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if (!(*p)->needs_symtab_index())
	(*p)->set_symtab_index(-1U);
      else
	{
	  (*p)->set_symtab_index(local_symbol_index);
	  ++local_symbol_index;
	  off += symsize;
	}
    }

  for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
       p != input_objects->relobj_end();
       ++p)
    {
      unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
                                                        off);
      off += (index - local_symbol_index) * symsize;
      local_symbol_index = index;
    }

  unsigned int local_symcount = local_symbol_index;
  gold_assert(local_symcount * symsize == off - startoff);

  off_t dynoff;
  size_t dyn_global_index;
  size_t dyncount;
  if (this->dynsym_section_ == NULL)
    {
      dynoff = 0;
      dyn_global_index = 0;
      dyncount = 0;
    }
  else
    {
      dyn_global_index = this->dynsym_section_->info();
      off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
      dynoff = this->dynsym_section_->offset() + locsize;
      dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
      gold_assert(static_cast<off_t>(dyncount * symsize)
		  == this->dynsym_section_->data_size() - locsize);
    }

  off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
			 &this->sympool_, &local_symcount);

  if (!parameters->options().strip_all())
    {
      this->sympool_.set_string_offsets();

      const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
      Output_section* osymtab = this->make_output_section(symtab_name,
							  elfcpp::SHT_SYMTAB,
							  0);
      this->symtab_section_ = osymtab;

      Output_section_data* pos = new Output_data_fixed_space(off - startoff,
							     align);
      osymtab->add_output_section_data(pos);

      const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
      Output_section* ostrtab = this->make_output_section(strtab_name,
							  elfcpp::SHT_STRTAB,
							  0);

      Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
      ostrtab->add_output_section_data(pstr);

      osymtab->set_file_offset(startoff);
      osymtab->finalize_data_size();
      osymtab->set_link_section(ostrtab);
      osymtab->set_info(local_symcount);
      osymtab->set_entsize(symsize);

      *poff = off;
    }
}

// Create the .shstrtab section, which holds the names of the
// sections.  At the time this is called, we have created all the
// output sections except .shstrtab itself.

Output_section*
Layout::create_shstrtab()
{
  // FIXME: We don't need to create a .shstrtab section if we are
  // stripping everything.

  const char* name = this->namepool_.add(".shstrtab", false, NULL);

  Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);

  // We can't write out this section until we've set all the section
  // names, and we don't set the names of compressed output sections
  // until relocations are complete.
  os->set_after_input_sections();

  Output_section_data* posd = new Output_data_strtab(&this->namepool_);
  os->add_output_section_data(posd);

  return os;
}

// Create the section headers.  SIZE is 32 or 64.  OFF is the file
// offset.

void
Layout::create_shdrs(off_t* poff)
{
  Output_section_headers* oshdrs;
  oshdrs = new Output_section_headers(this,
				      &this->segment_list_,
				      &this->section_list_,
				      &this->unattached_section_list_,
				      &this->namepool_);
  off_t off = align_address(*poff, oshdrs->addralign());
  oshdrs->set_address_and_file_offset(0, off);
  off += oshdrs->data_size();
  *poff = off;
  this->section_headers_ = oshdrs;
}

// Create the dynamic symbol table.

void
Layout::create_dynamic_symtab(const Input_objects* input_objects,
                              Symbol_table* symtab,
			      Output_section **pdynstr,
			      unsigned int* plocal_dynamic_count,
			      std::vector<Symbol*>* pdynamic_symbols,
			      Versions* pversions)
{
  // Count all the symbols in the dynamic symbol table, and set the
  // dynamic symbol indexes.

  // Skip symbol 0, which is always all zeroes.
  unsigned int index = 1;

  // Add STT_SECTION symbols for each Output section which needs one.
  for (Section_list::iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if (!(*p)->needs_dynsym_index())
	(*p)->set_dynsym_index(-1U);
      else
	{
	  (*p)->set_dynsym_index(index);
	  ++index;
	}
    }

  // Count the local symbols that need to go in the dynamic symbol table,
  // and set the dynamic symbol indexes.
  for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
       p != input_objects->relobj_end();
       ++p)
    {
      unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
      index = new_index;
    }

  unsigned int local_symcount = index;
  *plocal_dynamic_count = local_symcount;

  // FIXME: We have to tell set_dynsym_indexes whether the
  // -E/--export-dynamic option was used.
  index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
				     &this->dynpool_, pversions);

  int symsize;
  unsigned int align;
  const int size = parameters->target().get_size();
  if (size == 32)
    {
      symsize = elfcpp::Elf_sizes<32>::sym_size;
      align = 4;
    }
  else if (size == 64)
    {
      symsize = elfcpp::Elf_sizes<64>::sym_size;
      align = 8;
    }
  else
    gold_unreachable();

  // Create the dynamic symbol table section.

  Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
						       elfcpp::SHT_DYNSYM,
						       elfcpp::SHF_ALLOC,
						       false);

  Output_section_data* odata = new Output_data_fixed_space(index * symsize,
							   align);
  dynsym->add_output_section_data(odata);

  dynsym->set_info(local_symcount);
  dynsym->set_entsize(symsize);
  dynsym->set_addralign(align);

  this->dynsym_section_ = dynsym;

  Output_data_dynamic* const odyn = this->dynamic_data_;
  odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
  odyn->add_constant(elfcpp::DT_SYMENT, symsize);

  // Create the dynamic string table section.

  Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
						       elfcpp::SHT_STRTAB,
						       elfcpp::SHF_ALLOC,
						       false);

  Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
  dynstr->add_output_section_data(strdata);

  dynsym->set_link_section(dynstr);
  this->dynamic_section_->set_link_section(dynstr);

  odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
  odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);

  *pdynstr = dynstr;

  // Create the hash tables.

  if (strcmp(parameters->options().hash_style(), "sysv") == 0
      || strcmp(parameters->options().hash_style(), "both") == 0)
    {
      unsigned char* phash;
      unsigned int hashlen;
      Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
				    &phash, &hashlen);

      Output_section* hashsec = this->choose_output_section(NULL, ".hash",
							    elfcpp::SHT_HASH,
							    elfcpp::SHF_ALLOC,
							    false);

      Output_section_data* hashdata = new Output_data_const_buffer(phash,
								   hashlen,
								   align);
      hashsec->add_output_section_data(hashdata);

      hashsec->set_link_section(dynsym);
      hashsec->set_entsize(4);

      odyn->add_section_address(elfcpp::DT_HASH, hashsec);
    }

  if (strcmp(parameters->options().hash_style(), "gnu") == 0
      || strcmp(parameters->options().hash_style(), "both") == 0)
    {
      unsigned char* phash;
      unsigned int hashlen;
      Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
				    &phash, &hashlen);

      Output_section* hashsec = this->choose_output_section(NULL, ".gnu.hash",
							    elfcpp::SHT_GNU_HASH,
							    elfcpp::SHF_ALLOC,
							    false);

      Output_section_data* hashdata = new Output_data_const_buffer(phash,
								   hashlen,
								   align);
      hashsec->add_output_section_data(hashdata);

      hashsec->set_link_section(dynsym);
      hashsec->set_entsize(4);

      odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
    }
}

// Assign offsets to each local portion of the dynamic symbol table.

void
Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
{
  Output_section* dynsym = this->dynsym_section_;
  gold_assert(dynsym != NULL);

  off_t off = dynsym->offset();

  // Skip the dummy symbol at the start of the section.
  off += dynsym->entsize();

  for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
       p != input_objects->relobj_end();
       ++p)
    {
      unsigned int count = (*p)->set_local_dynsym_offset(off);
      off += count * dynsym->entsize();
    }
}

// Create the version sections.

void
Layout::create_version_sections(const Versions* versions,
				const Symbol_table* symtab,
				unsigned int local_symcount,
				const std::vector<Symbol*>& dynamic_symbols,
				const Output_section* dynstr)
{
  if (!versions->any_defs() && !versions->any_needs())
    return;

  switch (parameters->size_and_endianness())
    {
#ifdef HAVE_TARGET_32_LITTLE
    case Parameters::TARGET_32_LITTLE:
      this->sized_create_version_sections<32, false>(versions, symtab,
						     local_symcount,
						     dynamic_symbols, dynstr);
      break;
#endif
#ifdef HAVE_TARGET_32_BIG
    case Parameters::TARGET_32_BIG:
      this->sized_create_version_sections<32, true>(versions, symtab,
						    local_symcount,
						    dynamic_symbols, dynstr);
      break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
    case Parameters::TARGET_64_LITTLE:
      this->sized_create_version_sections<64, false>(versions, symtab,
						     local_symcount,
						     dynamic_symbols, dynstr);
      break;
#endif
#ifdef HAVE_TARGET_64_BIG
    case Parameters::TARGET_64_BIG:
      this->sized_create_version_sections<64, true>(versions, symtab,
						    local_symcount,
						    dynamic_symbols, dynstr);
      break;
#endif
    default:
      gold_unreachable();
    }
}

// Create the version sections, sized version.

template<int size, bool big_endian>
void
Layout::sized_create_version_sections(
    const Versions* versions,
    const Symbol_table* symtab,
    unsigned int local_symcount,
    const std::vector<Symbol*>& dynamic_symbols,
    const Output_section* dynstr)
{
  Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
						     elfcpp::SHT_GNU_versym,
						     elfcpp::SHF_ALLOC,
						     false);

  unsigned char* vbuf;
  unsigned int vsize;
  versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
						      local_symcount,
						      dynamic_symbols,
						      &vbuf, &vsize);

  Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);

  vsec->add_output_section_data(vdata);
  vsec->set_entsize(2);
  vsec->set_link_section(this->dynsym_section_);

  Output_data_dynamic* const odyn = this->dynamic_data_;
  odyn->add_section_address(elfcpp::DT_VERSYM, vsec);

  if (versions->any_defs())
    {
      Output_section* vdsec;
      vdsec= this->choose_output_section(NULL, ".gnu.version_d",
					 elfcpp::SHT_GNU_verdef,
					 elfcpp::SHF_ALLOC,
					 false);

      unsigned char* vdbuf;
      unsigned int vdsize;
      unsigned int vdentries;
      versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
						       &vdsize, &vdentries);

      Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
								 vdsize,
								 4);

      vdsec->add_output_section_data(vddata);
      vdsec->set_link_section(dynstr);
      vdsec->set_info(vdentries);

      odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
      odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
    }

  if (versions->any_needs())
    {
      Output_section* vnsec;
      vnsec = this->choose_output_section(NULL, ".gnu.version_r",
					  elfcpp::SHT_GNU_verneed,
					  elfcpp::SHF_ALLOC,
					  false);

      unsigned char* vnbuf;
      unsigned int vnsize;
      unsigned int vnentries;
      versions->need_section_contents<size, big_endian>(&this->dynpool_,
							&vnbuf, &vnsize,
							&vnentries);

      Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
								 vnsize,
								 4);

      vnsec->add_output_section_data(vndata);
      vnsec->set_link_section(dynstr);
      vnsec->set_info(vnentries);

      odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
      odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
    }
}

// Create the .interp section and PT_INTERP segment.

void
Layout::create_interp(const Target* target)
{
  const char* interp = this->options_.dynamic_linker();
  if (interp == NULL)
    {
      interp = target->dynamic_linker();
      gold_assert(interp != NULL);
    }

  size_t len = strlen(interp) + 1;

  Output_section_data* odata = new Output_data_const(interp, len, 1);

  Output_section* osec = this->choose_output_section(NULL, ".interp",
						     elfcpp::SHT_PROGBITS,
						     elfcpp::SHF_ALLOC,
						     false);
  osec->add_output_section_data(odata);

  if (!this->script_options_->saw_phdrs_clause())
    {
      Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
						       elfcpp::PF_R);
      oseg->add_initial_output_section(osec, elfcpp::PF_R);
    }
}

// Finish the .dynamic section and PT_DYNAMIC segment.

void
Layout::finish_dynamic_section(const Input_objects* input_objects,
			       const Symbol_table* symtab)
{
  if (!this->script_options_->saw_phdrs_clause())
    {
      Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
						       (elfcpp::PF_R
							| elfcpp::PF_W));
      oseg->add_initial_output_section(this->dynamic_section_,
				       elfcpp::PF_R | elfcpp::PF_W);
    }

  Output_data_dynamic* const odyn = this->dynamic_data_;

  for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
       p != input_objects->dynobj_end();
       ++p)
    {
      // FIXME: Handle --as-needed.
      odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
    }

  if (parameters->options().shared())
    {
      const char* soname = this->options_.soname();
      if (soname != NULL)
	odyn->add_string(elfcpp::DT_SONAME, soname);
    }

  // FIXME: Support --init and --fini.
  Symbol* sym = symtab->lookup("_init");
  if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
    odyn->add_symbol(elfcpp::DT_INIT, sym);

  sym = symtab->lookup("_fini");
  if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
    odyn->add_symbol(elfcpp::DT_FINI, sym);

  // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.

  // Add a DT_RPATH entry if needed.
  const General_options::Dir_list& rpath(this->options_.rpath());
  if (!rpath.empty())
    {
      std::string rpath_val;
      for (General_options::Dir_list::const_iterator p = rpath.begin();
           p != rpath.end();
           ++p)
        {
          if (rpath_val.empty())
            rpath_val = p->name();
          else
            {
              // Eliminate duplicates.
              General_options::Dir_list::const_iterator q;
              for (q = rpath.begin(); q != p; ++q)
		if (q->name() == p->name())
                  break;
              if (q == p)
                {
                  rpath_val += ':';
                  rpath_val += p->name();
                }
            }
        }

      odyn->add_string(elfcpp::DT_RPATH, rpath_val);
    }

  // Look for text segments that have dynamic relocations.
  bool have_textrel = false;
  if (!this->script_options_->saw_sections_clause())
    {
      for (Segment_list::const_iterator p = this->segment_list_.begin();
           p != this->segment_list_.end();
           ++p)
        {
          if (((*p)->flags() & elfcpp::PF_W) == 0
              && (*p)->dynamic_reloc_count() > 0)
            {
              have_textrel = true;
              break;
            }
        }
    }
  else
    {
      // We don't know the section -> segment mapping, so we are
      // conservative and just look for readonly sections with
      // relocations.  If those sections wind up in writable segments,
      // then we have created an unnecessary DT_TEXTREL entry.
      for (Section_list::const_iterator p = this->section_list_.begin();
           p != this->section_list_.end();
           ++p)
        {
          if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
              && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
              && ((*p)->dynamic_reloc_count() > 0))
            {
              have_textrel = true;
              break;
            }
        }
    }

  // Add a DT_FLAGS entry. We add it even if no flags are set so that
  // post-link tools can easily modify these flags if desired.
  unsigned int flags = 0;
  if (have_textrel)
    {
      // Add a DT_TEXTREL for compatibility with older loaders.
      odyn->add_constant(elfcpp::DT_TEXTREL, 0);
      flags |= elfcpp::DF_TEXTREL;
    }
  if (parameters->options().shared() && this->has_static_tls())
    flags |= elfcpp::DF_STATIC_TLS;
  odyn->add_constant(elfcpp::DT_FLAGS, flags);
}

// The mapping of .gnu.linkonce section names to real section names.

#define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
{
  MAPPING_INIT("d.rel.ro", ".data.rel.ro"),	// Must be before "d".
  MAPPING_INIT("t", ".text"),
  MAPPING_INIT("r", ".rodata"),
  MAPPING_INIT("d", ".data"),
  MAPPING_INIT("b", ".bss"),
  MAPPING_INIT("s", ".sdata"),
  MAPPING_INIT("sb", ".sbss"),
  MAPPING_INIT("s2", ".sdata2"),
  MAPPING_INIT("sb2", ".sbss2"),
  MAPPING_INIT("wi", ".debug_info"),
  MAPPING_INIT("td", ".tdata"),
  MAPPING_INIT("tb", ".tbss"),
  MAPPING_INIT("lr", ".lrodata"),
  MAPPING_INIT("l", ".ldata"),
  MAPPING_INIT("lb", ".lbss"),
};
#undef MAPPING_INIT

const int Layout::linkonce_mapping_count =
  sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]);

// Return the name of the output section to use for a .gnu.linkonce
// section.  This is based on the default ELF linker script of the old
// GNU linker.  For example, we map a name like ".gnu.linkonce.t.foo"
// to ".text".  Set *PLEN to the length of the name.  *PLEN is
// initialized to the length of NAME.

const char*
Layout::linkonce_output_name(const char* name, size_t *plen)
{
  const char* s = name + sizeof(".gnu.linkonce") - 1;
  if (*s != '.')
    return name;
  ++s;
  const Linkonce_mapping* plm = linkonce_mapping;
  for (int i = 0; i < linkonce_mapping_count; ++i, ++plm)
    {
      if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.')
	{
	  *plen = plm->tolen;
	  return plm->to;
	}
    }
  return name;
}

// Choose the output section name to use given an input section name.
// Set *PLEN to the length of the name.  *PLEN is initialized to the
// length of NAME.

const char*
Layout::output_section_name(const char* name, size_t* plen)
{
  if (Layout::is_linkonce(name))
    {
      // .gnu.linkonce sections are laid out as though they were named
      // for the sections are placed into.
      return Layout::linkonce_output_name(name, plen);
    }

  // gcc 4.3 generates the following sorts of section names when it
  // needs a section name specific to a function:
  //   .text.FN
  //   .rodata.FN
  //   .sdata2.FN
  //   .data.FN
  //   .data.rel.FN
  //   .data.rel.local.FN
  //   .data.rel.ro.FN
  //   .data.rel.ro.local.FN
  //   .sdata.FN
  //   .bss.FN
  //   .sbss.FN
  //   .tdata.FN
  //   .tbss.FN

  // The GNU linker maps all of those to the part before the .FN,
  // except that .data.rel.local.FN is mapped to .data, and
  // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
  // beginning with .data.rel.ro.local are grouped together.

  // For an anonymous namespace, the string FN can contain a '.'.

  // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
  // GNU linker maps to .rodata.

  // The .data.rel.ro sections enable a security feature triggered by
  // the -z relro option.  Section which need to be relocated at
  // program startup time but which may be readonly after startup are
  // grouped into .data.rel.ro.  They are then put into a PT_GNU_RELRO
  // segment.  The dynamic linker will make that segment writable,
  // perform relocations, and then make it read-only.  FIXME: We do
  // not yet implement this optimization.

  // It is hard to handle this in a principled way.

  // These are the rules we follow:

  // If the section name has no initial '.', or no dot other than an
  // initial '.', we use the name unchanged (i.e., "mysection" and
  // ".text" are unchanged).

  // If the name starts with ".data.rel.ro" we use ".data.rel.ro".

  // Otherwise, we drop the second '.' and everything that comes after
  // it (i.e., ".text.XXX" becomes ".text").

  const char* s = name;
  if (*s != '.')
    return name;
  ++s;
  const char* sdot = strchr(s, '.');
  if (sdot == NULL)
    return name;

  const char* const data_rel_ro = ".data.rel.ro";
  if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
    {
      *plen = strlen(data_rel_ro);
      return data_rel_ro;
    }

  *plen = sdot - name;
  return name;
}

// Record the signature of a comdat section, and return whether to
// include it in the link.  If GROUP is true, this is a regular
// section group.  If GROUP is false, this is a group signature
// derived from the name of a linkonce section.  We want linkonce
// signatures and group signatures to block each other, but we don't
// want a linkonce signature to block another linkonce signature.

bool
Layout::add_comdat(const char* signature, bool group)
{
  std::string sig(signature);
  std::pair<Signatures::iterator, bool> ins(
    this->signatures_.insert(std::make_pair(sig, group)));

  if (ins.second)
    {
      // This is the first time we've seen this signature.
      return true;
    }

  if (ins.first->second)
    {
      // We've already seen a real section group with this signature.
      return false;
    }
  else if (group)
    {
      // This is a real section group, and we've already seen a
      // linkonce section with this signature.  Record that we've seen
      // a section group, and don't include this section group.
      ins.first->second = true;
      return false;
    }
  else
    {
      // We've already seen a linkonce section and this is a linkonce
      // section.  These don't block each other--this may be the same
      // symbol name with different section types.
      return true;
    }
}

// Store the allocated sections into the section list.

void
Layout::get_allocated_sections(Section_list* section_list) const
{
  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
      section_list->push_back(*p);
}

// Create an output segment.

Output_segment*
Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
{
  gold_assert(!parameters->options().relocatable());
  Output_segment* oseg = new Output_segment(type, flags);
  this->segment_list_.push_back(oseg);
  return oseg;
}

// Write out the Output_sections.  Most won't have anything to write,
// since most of the data will come from input sections which are
// handled elsewhere.  But some Output_sections do have Output_data.

void
Layout::write_output_sections(Output_file* of) const
{
  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if (!(*p)->after_input_sections())
	(*p)->write(of);
    }
}

// Write out data not associated with a section or the symbol table.

void
Layout::write_data(const Symbol_table* symtab, Output_file* of) const
{
  if (!parameters->options().strip_all())
    {
      const Output_section* symtab_section = this->symtab_section_;
      for (Section_list::const_iterator p = this->section_list_.begin();
	   p != this->section_list_.end();
	   ++p)
	{
	  if ((*p)->needs_symtab_index())
	    {
	      gold_assert(symtab_section != NULL);
	      unsigned int index = (*p)->symtab_index();
	      gold_assert(index > 0 && index != -1U);
	      off_t off = (symtab_section->offset()
			   + index * symtab_section->entsize());
	      symtab->write_section_symbol(*p, of, off);
	    }
	}
    }

  const Output_section* dynsym_section = this->dynsym_section_;
  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if ((*p)->needs_dynsym_index())
	{
	  gold_assert(dynsym_section != NULL);
	  unsigned int index = (*p)->dynsym_index();
	  gold_assert(index > 0 && index != -1U);
	  off_t off = (dynsym_section->offset()
		       + index * dynsym_section->entsize());
	  symtab->write_section_symbol(*p, of, off);
	}
    }

  // Write out the Output_data which are not in an Output_section.
  for (Data_list::const_iterator p = this->special_output_list_.begin();
       p != this->special_output_list_.end();
       ++p)
    (*p)->write(of);
}

// Write out the Output_sections which can only be written after the
// input sections are complete.

void
Layout::write_sections_after_input_sections(Output_file* of)
{
  // Determine the final section offsets, and thus the final output
  // file size.  Note we finalize the .shstrab last, to allow the
  // after_input_section sections to modify their section-names before
  // writing.
  if (this->any_postprocessing_sections_)
    {
      off_t off = this->output_file_size_;
      off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
      
      // Now that we've finalized the names, we can finalize the shstrab.
      off =
	this->set_section_offsets(off,
				  STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);

      if (off > this->output_file_size_)
	{
	  of->resize(off);
	  this->output_file_size_ = off;
	}
    }

  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    {
      if ((*p)->after_input_sections())
	(*p)->write(of);
    }

  this->section_headers_->write(of);
}

// If the build ID requires computing a checksum, do so here, and
// write it out.  We compute a checksum over the entire file because
// that is simplest.

void
Layout::write_build_id(Output_file* of) const
{
  if (this->build_id_note_ == NULL)
    return;

  const unsigned char* iv = of->get_input_view(0, this->output_file_size_);

  unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
					  this->build_id_note_->data_size());

  const char* style = parameters->options().build_id();
  if (strcmp(style, "sha1") == 0)
    {
      sha1_ctx ctx;
      sha1_init_ctx(&ctx);
      sha1_process_bytes(iv, this->output_file_size_, &ctx);
      sha1_finish_ctx(&ctx, ov);
    }
  else if (strcmp(style, "md5") == 0)
    {
      md5_ctx ctx;
      md5_init_ctx(&ctx);
      md5_process_bytes(iv, this->output_file_size_, &ctx);
      md5_finish_ctx(&ctx, ov);
    }
  else
    gold_unreachable();

  of->write_output_view(this->build_id_note_->offset(),
			this->build_id_note_->data_size(),
			ov);

  of->free_input_view(0, this->output_file_size_, iv);
}

// Write out a binary file.  This is called after the link is
// complete.  IN is the temporary output file we used to generate the
// ELF code.  We simply walk through the segments, read them from
// their file offset in IN, and write them to their load address in
// the output file.  FIXME: with a bit more work, we could support
// S-records and/or Intel hex format here.

void
Layout::write_binary(Output_file* in) const
{
  gold_assert(this->options_.oformat_enum()
	      == General_options::OBJECT_FORMAT_BINARY);

  // Get the size of the binary file.
  uint64_t max_load_address = 0;
  for (Segment_list::const_iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
	{
	  uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
	  if (max_paddr > max_load_address)
	    max_load_address = max_paddr;
	}
    }

  Output_file out(parameters->options().output_file_name());
  out.open(max_load_address);

  for (Segment_list::const_iterator p = this->segment_list_.begin();
       p != this->segment_list_.end();
       ++p)
    {
      if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
	{
	  const unsigned char* vin = in->get_input_view((*p)->offset(),
							(*p)->filesz());
	  unsigned char* vout = out.get_output_view((*p)->paddr(),
						    (*p)->filesz());
	  memcpy(vout, vin, (*p)->filesz());
	  out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
	  in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
	}
    }

  out.close();
}

// Print statistical information to stderr.  This is used for --stats.

void
Layout::print_stats() const
{
  this->namepool_.print_stats("section name pool");
  this->sympool_.print_stats("output symbol name pool");
  this->dynpool_.print_stats("dynamic name pool");

  for (Section_list::const_iterator p = this->section_list_.begin();
       p != this->section_list_.end();
       ++p)
    (*p)->print_merge_stats();
}

// Write_sections_task methods.

// We can always run this task.

Task_token*
Write_sections_task::is_runnable()
{
  return NULL;
}

// We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
// when finished.

void
Write_sections_task::locks(Task_locker* tl)
{
  tl->add(this, this->output_sections_blocker_);
  tl->add(this, this->final_blocker_);
}

// Run the task--write out the data.

void
Write_sections_task::run(Workqueue*)
{
  this->layout_->write_output_sections(this->of_);
}

// Write_data_task methods.

// We can always run this task.

Task_token*
Write_data_task::is_runnable()
{
  return NULL;
}

// We need to unlock FINAL_BLOCKER when finished.

void
Write_data_task::locks(Task_locker* tl)
{
  tl->add(this, this->final_blocker_);
}

// Run the task--write out the data.

void
Write_data_task::run(Workqueue*)
{
  this->layout_->write_data(this->symtab_, this->of_);
}

// Write_symbols_task methods.

// We can always run this task.

Task_token*
Write_symbols_task::is_runnable()
{
  return NULL;
}

// We need to unlock FINAL_BLOCKER when finished.

void
Write_symbols_task::locks(Task_locker* tl)
{
  tl->add(this, this->final_blocker_);
}

// Run the task--write out the symbols.

void
Write_symbols_task::run(Workqueue*)
{
  this->symtab_->write_globals(this->input_objects_, this->sympool_,
			       this->dynpool_, this->of_);
}

// Write_after_input_sections_task methods.

// We can only run this task after the input sections have completed.

Task_token*
Write_after_input_sections_task::is_runnable()
{
  if (this->input_sections_blocker_->is_blocked())
    return this->input_sections_blocker_;
  return NULL;
}

// We need to unlock FINAL_BLOCKER when finished.

void
Write_after_input_sections_task::locks(Task_locker* tl)
{
  tl->add(this, this->final_blocker_);
}

// Run the task.

void
Write_after_input_sections_task::run(Workqueue*)
{
  this->layout_->write_sections_after_input_sections(this->of_);
}

// Close_task_runner methods.

// Run the task--close the file.

void
Close_task_runner::run(Workqueue*, const Task*)
{
  // If we need to compute a checksum for the BUILD if, we do so here.
  this->layout_->write_build_id(this->of_);

  // If we've been asked to create a binary file, we do so here.
  if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
    this->layout_->write_binary(this->of_);

  this->of_->close();
}

// Instantiate the templates we need.  We could use the configure
// script to restrict this to only the ones for implemented targets.

#ifdef HAVE_TARGET_32_LITTLE
template
Output_section*
Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
			  const char* name,
			  const elfcpp::Shdr<32, false>& shdr,
			  unsigned int, unsigned int, off_t*);
#endif

#ifdef HAVE_TARGET_32_BIG
template
Output_section*
Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
			 const char* name,
			 const elfcpp::Shdr<32, true>& shdr,
			 unsigned int, unsigned int, off_t*);
#endif

#ifdef HAVE_TARGET_64_LITTLE
template
Output_section*
Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
			  const char* name,
			  const elfcpp::Shdr<64, false>& shdr,
			  unsigned int, unsigned int, off_t*);
#endif

#ifdef HAVE_TARGET_64_BIG
template
Output_section*
Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
			 const char* name,
			 const elfcpp::Shdr<64, true>& shdr,
			 unsigned int, unsigned int, off_t*);
#endif

#ifdef HAVE_TARGET_32_LITTLE
template
Output_section*
Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
				unsigned int reloc_shndx,
				const elfcpp::Shdr<32, false>& shdr,
				Output_section* data_section,
				Relocatable_relocs* rr);
#endif

#ifdef HAVE_TARGET_32_BIG
template
Output_section*
Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
			       unsigned int reloc_shndx,
			       const elfcpp::Shdr<32, true>& shdr,
			       Output_section* data_section,
			       Relocatable_relocs* rr);
#endif

#ifdef HAVE_TARGET_64_LITTLE
template
Output_section*
Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
				unsigned int reloc_shndx,
				const elfcpp::Shdr<64, false>& shdr,
				Output_section* data_section,
				Relocatable_relocs* rr);
#endif

#ifdef HAVE_TARGET_64_BIG
template
Output_section*
Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
			       unsigned int reloc_shndx,
			       const elfcpp::Shdr<64, true>& shdr,
			       Output_section* data_section,
			       Relocatable_relocs* rr);
#endif

#ifdef HAVE_TARGET_32_LITTLE
template
void
Layout::layout_group<32, false>(Symbol_table* symtab,
				Sized_relobj<32, false>* object,
				unsigned int,
				const char* group_section_name,
				const char* signature,
				const elfcpp::Shdr<32, false>& shdr,
				const elfcpp::Elf_Word* contents);
#endif

#ifdef HAVE_TARGET_32_BIG
template
void
Layout::layout_group<32, true>(Symbol_table* symtab,
			       Sized_relobj<32, true>* object,
			       unsigned int,
			       const char* group_section_name,
			       const char* signature,
			       const elfcpp::Shdr<32, true>& shdr,
			       const elfcpp::Elf_Word* contents);
#endif

#ifdef HAVE_TARGET_64_LITTLE
template
void
Layout::layout_group<64, false>(Symbol_table* symtab,
				Sized_relobj<64, false>* object,
				unsigned int,
				const char* group_section_name,
				const char* signature,
				const elfcpp::Shdr<64, false>& shdr,
				const elfcpp::Elf_Word* contents);
#endif

#ifdef HAVE_TARGET_64_BIG
template
void
Layout::layout_group<64, true>(Symbol_table* symtab,
			       Sized_relobj<64, true>* object,
			       unsigned int,
			       const char* group_section_name,
			       const char* signature,
			       const elfcpp::Shdr<64, true>& shdr,
			       const elfcpp::Elf_Word* contents);
#endif

#ifdef HAVE_TARGET_32_LITTLE
template
Output_section*
Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
				   const unsigned char* symbols,
				   off_t symbols_size,
				   const unsigned char* symbol_names,
				   off_t symbol_names_size,
				   unsigned int shndx,
				   const elfcpp::Shdr<32, false>& shdr,
				   unsigned int reloc_shndx,
				   unsigned int reloc_type,
				   off_t* off);
#endif

#ifdef HAVE_TARGET_32_BIG
template
Output_section*
Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
				   const unsigned char* symbols,
				   off_t symbols_size,
				  const unsigned char* symbol_names,
				  off_t symbol_names_size,
				  unsigned int shndx,
				  const elfcpp::Shdr<32, true>& shdr,
				  unsigned int reloc_shndx,
				  unsigned int reloc_type,
				  off_t* off);
#endif

#ifdef HAVE_TARGET_64_LITTLE
template
Output_section*
Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
				   const unsigned char* symbols,
				   off_t symbols_size,
				   const unsigned char* symbol_names,
				   off_t symbol_names_size,
				   unsigned int shndx,
				   const elfcpp::Shdr<64, false>& shdr,
				   unsigned int reloc_shndx,
				   unsigned int reloc_type,
				   off_t* off);
#endif

#ifdef HAVE_TARGET_64_BIG
template
Output_section*
Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
				   const unsigned char* symbols,
				   off_t symbols_size,
				  const unsigned char* symbol_names,
				  off_t symbol_names_size,
				  unsigned int shndx,
				  const elfcpp::Shdr<64, true>& shdr,
				  unsigned int reloc_shndx,
				  unsigned int reloc_type,
				  off_t* off);
#endif

} // End namespace gold.