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
use alloc::vec::Vec;
use core::fmt;
use core::num::Wrapping;
use core::result;

use crate::common::{
    DebugLineOffset, DebugLineStrOffset, DebugStrOffset, DebugStrOffsetsIndex, Encoding, Format,
    LineEncoding, SectionId,
};
use crate::constants;
use crate::endianity::Endianity;
use crate::read::{AttributeValue, EndianSlice, Error, Reader, ReaderOffset, Result, Section};

/// The `DebugLine` struct contains the source location to instruction mapping
/// found in the `.debug_line` section.
#[derive(Debug, Default, Clone, Copy)]
pub struct DebugLine<R> {
    debug_line_section: R,
}

impl<'input, Endian> DebugLine<EndianSlice<'input, Endian>>
where
    Endian: Endianity,
{
    /// Construct a new `DebugLine` instance from the data in the `.debug_line`
    /// section.
    ///
    /// It is the caller's responsibility to read the `.debug_line` section and
    /// present it as a `&[u8]` slice. That means using some ELF loader on
    /// Linux, a Mach-O loader on OSX, etc.
    ///
    /// ```
    /// use gimli::{DebugLine, LittleEndian};
    ///
    /// # let buf = [0x00, 0x01, 0x02, 0x03];
    /// # let read_debug_line_section_somehow = || &buf;
    /// let debug_line = DebugLine::new(read_debug_line_section_somehow(), LittleEndian);
    /// ```
    pub fn new(debug_line_section: &'input [u8], endian: Endian) -> Self {
        Self::from(EndianSlice::new(debug_line_section, endian))
    }
}

impl<R: Reader> DebugLine<R> {
    /// Parse the line number program whose header is at the given `offset` in the
    /// `.debug_line` section.
    ///
    /// The `address_size` must match the compilation unit that the lines apply to.
    /// The `comp_dir` should be from the `DW_AT_comp_dir` attribute of the compilation
    /// unit. The `comp_name` should be from the `DW_AT_name` attribute of the
    /// compilation unit.
    ///
    /// ```rust,no_run
    /// use gimli::{DebugLine, DebugLineOffset, IncompleteLineProgram, EndianSlice, LittleEndian};
    ///
    /// # let buf = [];
    /// # let read_debug_line_section_somehow = || &buf;
    /// let debug_line = DebugLine::new(read_debug_line_section_somehow(), LittleEndian);
    ///
    /// // In a real example, we'd grab the offset via a compilation unit
    /// // entry's `DW_AT_stmt_list` attribute, and the address size from that
    /// // unit directly.
    /// let offset = DebugLineOffset(0);
    /// let address_size = 8;
    ///
    /// let program = debug_line.program(offset, address_size, None, None)
    ///     .expect("should have found a header at that offset, and parsed it OK");
    /// ```
    pub fn program(
        &self,
        offset: DebugLineOffset<R::Offset>,
        address_size: u8,
        comp_dir: Option<R>,
        comp_name: Option<R>,
    ) -> Result<IncompleteLineProgram<R>> {
        let input = &mut self.debug_line_section.clone();
        input.skip(offset.0)?;
        let header = LineProgramHeader::parse(input, offset, address_size, comp_dir, comp_name)?;
        let program = IncompleteLineProgram { header };
        Ok(program)
    }
}

impl<T> DebugLine<T> {
    /// Create a `DebugLine` section that references the data in `self`.
    ///
    /// This is useful when `R` implements `Reader` but `T` does not.
    ///
    /// ## Example Usage
    ///
    /// ```rust,no_run
    /// # let load_section = || unimplemented!();
    /// // Read the DWARF section into a `Vec` with whatever object loader you're using.
    /// let owned_section: gimli::DebugLine<Vec<u8>> = load_section();
    /// // Create a reference to the DWARF section.
    /// let section = owned_section.borrow(|section| {
    ///     gimli::EndianSlice::new(&section, gimli::LittleEndian)
    /// });
    /// ```
    pub fn borrow<'a, F, R>(&'a self, mut borrow: F) -> DebugLine<R>
    where
        F: FnMut(&'a T) -> R,
    {
        borrow(&self.debug_line_section).into()
    }
}

impl<R> Section<R> for DebugLine<R> {
    fn id() -> SectionId {
        SectionId::DebugLine
    }

    fn reader(&self) -> &R {
        &self.debug_line_section
    }
}

impl<R> From<R> for DebugLine<R> {
    fn from(debug_line_section: R) -> Self {
        DebugLine { debug_line_section }
    }
}

/// Deprecated. `LineNumberProgram` has been renamed to `LineProgram`.
#[deprecated(note = "LineNumberProgram has been renamed to LineProgram, use that instead.")]
pub type LineNumberProgram<R, Offset> = dyn LineProgram<R, Offset>;

/// A `LineProgram` provides access to a `LineProgramHeader` and
/// a way to add files to the files table if necessary. Gimli consumers should
/// never need to use or see this trait.
pub trait LineProgram<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    /// Get a reference to the held `LineProgramHeader`.
    fn header(&self) -> &LineProgramHeader<R, Offset>;
    /// Add a file to the file table if necessary.
    fn add_file(&mut self, file: FileEntry<R, Offset>);
}

impl<R, Offset> LineProgram<R, Offset> for IncompleteLineProgram<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    fn header(&self) -> &LineProgramHeader<R, Offset> {
        &self.header
    }
    fn add_file(&mut self, file: FileEntry<R, Offset>) {
        self.header.file_names.push(file);
    }
}

impl<'program, R, Offset> LineProgram<R, Offset> for &'program CompleteLineProgram<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    fn header(&self) -> &LineProgramHeader<R, Offset> {
        &self.header
    }
    fn add_file(&mut self, _: FileEntry<R, Offset>) {
        // Nop. Our file table is already complete.
    }
}

/// Deprecated. `StateMachine` has been renamed to `LineRows`.
#[deprecated(note = "StateMachine has been renamed to LineRows, use that instead.")]
pub type StateMachine<R, Program, Offset> = LineRows<R, Program, Offset>;

/// Executes a `LineProgram` to iterate over the rows in the matrix of line number information.
///
/// "The hypothetical machine used by a consumer of the line number information
/// to expand the byte-coded instruction stream into a matrix of line number
/// information." -- Section 6.2.1
#[derive(Debug, Clone)]
pub struct LineRows<R, Program, Offset = <R as Reader>::Offset>
where
    Program: LineProgram<R, Offset>,
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    program: Program,
    row: LineRow,
    instructions: LineInstructions<R>,
}

type OneShotLineRows<R, Offset = <R as Reader>::Offset> =
    LineRows<R, IncompleteLineProgram<R, Offset>, Offset>;

type ResumedLineRows<'program, R, Offset = <R as Reader>::Offset> =
    LineRows<R, &'program CompleteLineProgram<R, Offset>, Offset>;

impl<R, Program, Offset> LineRows<R, Program, Offset>
where
    Program: LineProgram<R, Offset>,
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    #[allow(clippy::new_ret_no_self)]
    fn new(program: IncompleteLineProgram<R, Offset>) -> OneShotLineRows<R, Offset> {
        let row = LineRow::new(program.header());
        let instructions = LineInstructions {
            input: program.header().program_buf.clone(),
        };
        LineRows {
            program,
            row,
            instructions,
        }
    }

    fn resume<'program>(
        program: &'program CompleteLineProgram<R, Offset>,
        sequence: &LineSequence<R>,
    ) -> ResumedLineRows<'program, R, Offset> {
        let row = LineRow::new(program.header());
        let instructions = sequence.instructions.clone();
        LineRows {
            program,
            row,
            instructions,
        }
    }

    /// Get a reference to the header for this state machine's line number
    /// program.
    #[inline]
    pub fn header(&self) -> &LineProgramHeader<R, Offset> {
        self.program.header()
    }

    /// Parse and execute the next instructions in the line number program until
    /// another row in the line number matrix is computed.
    ///
    /// The freshly computed row is returned as `Ok(Some((header, row)))`.
    /// If the matrix is complete, and there are no more new rows in the line
    /// number matrix, then `Ok(None)` is returned. If there was an error parsing
    /// an instruction, then `Err(e)` is returned.
    ///
    /// Unfortunately, the references mean that this cannot be a
    /// `FallibleIterator`.
    pub fn next_row(&mut self) -> Result<Option<(&LineProgramHeader<R, Offset>, &LineRow)>> {
        // Perform any reset that was required after copying the previous row.
        self.row.reset(self.program.header());

        loop {
            // Split the borrow here, rather than calling `self.header()`.
            match self.instructions.next_instruction(self.program.header()) {
                Err(err) => return Err(err),
                Ok(None) => return Ok(None),
                Ok(Some(instruction)) => {
                    if self.row.execute(instruction, &mut self.program) {
                        return Ok(Some((self.header(), &self.row)));
                    }
                    // Fall through, parse the next instruction, and see if that
                    // yields a row.
                }
            }
        }
    }
}

/// Deprecated. `Opcode` has been renamed to `LineInstruction`.
#[deprecated(note = "Opcode has been renamed to LineInstruction, use that instead.")]
pub type Opcode<R> = LineInstruction<R, <R as Reader>::Offset>;

/// A parsed line number program instruction.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum LineInstruction<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    /// > ### 6.2.5.1 Special Opcodes
    /// >
    /// > Each ubyte special opcode has the following effect on the state machine:
    /// >
    /// >   1. Add a signed integer to the line register.
    /// >
    /// >   2. Modify the operation pointer by incrementing the address and
    /// >   op_index registers as described below.
    /// >
    /// >   3. Append a row to the matrix using the current values of the state
    /// >   machine registers.
    /// >
    /// >   4. Set the basic_block register to “false.”
    /// >
    /// >   5. Set the prologue_end register to “false.”
    /// >
    /// >   6. Set the epilogue_begin register to “false.”
    /// >
    /// >   7. Set the discriminator register to 0.
    /// >
    /// > All of the special opcodes do those same seven things; they differ from
    /// > one another only in what values they add to the line, address and
    /// > op_index registers.
    Special(u8),

    /// "[`LineInstruction::Copy`] appends a row to the matrix using the current
    /// values of the state machine registers. Then it sets the discriminator
    /// register to 0, and sets the basic_block, prologue_end and epilogue_begin
    /// registers to “false.”"
    Copy,

    /// "The DW_LNS_advance_pc opcode takes a single unsigned LEB128 operand as
    /// the operation advance and modifies the address and op_index registers
    /// [the same as `LineInstruction::Special`]"
    AdvancePc(u64),

    /// "The DW_LNS_advance_line opcode takes a single signed LEB128 operand and
    /// adds that value to the line register of the state machine."
    AdvanceLine(i64),

    /// "The DW_LNS_set_file opcode takes a single unsigned LEB128 operand and
    /// stores it in the file register of the state machine."
    SetFile(u64),

    /// "The DW_LNS_set_column opcode takes a single unsigned LEB128 operand and
    /// stores it in the column register of the state machine."
    SetColumn(u64),

    /// "The DW_LNS_negate_stmt opcode takes no operands. It sets the is_stmt
    /// register of the state machine to the logical negation of its current
    /// value."
    NegateStatement,

    /// "The DW_LNS_set_basic_block opcode takes no operands. It sets the
    /// basic_block register of the state machine to “true.”"
    SetBasicBlock,

    /// > The DW_LNS_const_add_pc opcode takes no operands. It advances the
    /// > address and op_index registers by the increments corresponding to
    /// > special opcode 255.
    /// >
    /// > When the line number program needs to advance the address by a small
    /// > amount, it can use a single special opcode, which occupies a single
    /// > byte. When it needs to advance the address by up to twice the range of
    /// > the last special opcode, it can use DW_LNS_const_add_pc followed by a
    /// > special opcode, for a total of two bytes. Only if it needs to advance
    /// > the address by more than twice that range will it need to use both
    /// > DW_LNS_advance_pc and a special opcode, requiring three or more bytes.
    ConstAddPc,

    /// > The DW_LNS_fixed_advance_pc opcode takes a single uhalf (unencoded)
    /// > operand and adds it to the address register of the state machine and
    /// > sets the op_index register to 0. This is the only standard opcode whose
    /// > operand is not a variable length number. It also does not multiply the
    /// > operand by the minimum_instruction_length field of the header.
    FixedAddPc(u16),

    /// "[`LineInstruction::SetPrologueEnd`] sets the prologue_end register to “true”."
    SetPrologueEnd,

    /// "[`LineInstruction::SetEpilogueBegin`] sets the epilogue_begin register to
    /// “true”."
    SetEpilogueBegin,

    /// "The DW_LNS_set_isa opcode takes a single unsigned LEB128 operand and
    /// stores that value in the isa register of the state machine."
    SetIsa(u64),

    /// An unknown standard opcode with zero operands.
    UnknownStandard0(constants::DwLns),

    /// An unknown standard opcode with one operand.
    UnknownStandard1(constants::DwLns, u64),

    /// An unknown standard opcode with multiple operands.
    UnknownStandardN(constants::DwLns, R),

    /// > [`LineInstruction::EndSequence`] sets the end_sequence register of the state
    /// > machine to “true” and appends a row to the matrix using the current
    /// > values of the state-machine registers. Then it resets the registers to
    /// > the initial values specified above (see Section 6.2.2). Every line
    /// > number program sequence must end with a DW_LNE_end_sequence instruction
    /// > which creates a row whose address is that of the byte after the last
    /// > target machine instruction of the sequence.
    EndSequence,

    /// > The DW_LNE_set_address opcode takes a single relocatable address as an
    /// > operand. The size of the operand is the size of an address on the target
    /// > machine. It sets the address register to the value given by the
    /// > relocatable address and sets the op_index register to 0.
    /// >
    /// > All of the other line number program opcodes that affect the address
    /// > register add a delta to it. This instruction stores a relocatable value
    /// > into it instead.
    SetAddress(u64),

    /// Defines a new source file in the line number program and appends it to
    /// the line number program header's list of source files.
    DefineFile(FileEntry<R, Offset>),

    /// "The DW_LNE_set_discriminator opcode takes a single parameter, an
    /// unsigned LEB128 integer. It sets the discriminator register to the new
    /// value."
    SetDiscriminator(u64),

    /// An unknown extended opcode and the slice of its unparsed operands.
    UnknownExtended(constants::DwLne, R),
}

impl<R, Offset> LineInstruction<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    fn parse<'header>(
        header: &'header LineProgramHeader<R>,
        input: &mut R,
    ) -> Result<LineInstruction<R>>
    where
        R: 'header,
    {
        let opcode = input.read_u8()?;
        if opcode == 0 {
            let length = input.read_uleb128().and_then(R::Offset::from_u64)?;
            let mut instr_rest = input.split(length)?;
            let opcode = instr_rest.read_u8()?;

            match constants::DwLne(opcode) {
                constants::DW_LNE_end_sequence => Ok(LineInstruction::EndSequence),

                constants::DW_LNE_set_address => {
                    let address = instr_rest.read_address(header.address_size())?;
                    Ok(LineInstruction::SetAddress(address))
                }

                constants::DW_LNE_define_file => {
                    if header.version() <= 4 {
                        let path_name = instr_rest.read_null_terminated_slice()?;
                        let entry = FileEntry::parse(&mut instr_rest, path_name)?;
                        Ok(LineInstruction::DefineFile(entry))
                    } else {
                        Ok(LineInstruction::UnknownExtended(
                            constants::DW_LNE_define_file,
                            instr_rest,
                        ))
                    }
                }

                constants::DW_LNE_set_discriminator => {
                    let discriminator = instr_rest.read_uleb128()?;
                    Ok(LineInstruction::SetDiscriminator(discriminator))
                }

                otherwise => Ok(LineInstruction::UnknownExtended(otherwise, instr_rest)),
            }
        } else if opcode >= header.opcode_base {
            Ok(LineInstruction::Special(opcode))
        } else {
            match constants::DwLns(opcode) {
                constants::DW_LNS_copy => Ok(LineInstruction::Copy),

                constants::DW_LNS_advance_pc => {
                    let advance = input.read_uleb128()?;
                    Ok(LineInstruction::AdvancePc(advance))
                }

                constants::DW_LNS_advance_line => {
                    let increment = input.read_sleb128()?;
                    Ok(LineInstruction::AdvanceLine(increment))
                }

                constants::DW_LNS_set_file => {
                    let file = input.read_uleb128()?;
                    Ok(LineInstruction::SetFile(file))
                }

                constants::DW_LNS_set_column => {
                    let column = input.read_uleb128()?;
                    Ok(LineInstruction::SetColumn(column))
                }

                constants::DW_LNS_negate_stmt => Ok(LineInstruction::NegateStatement),

                constants::DW_LNS_set_basic_block => Ok(LineInstruction::SetBasicBlock),

                constants::DW_LNS_const_add_pc => Ok(LineInstruction::ConstAddPc),

                constants::DW_LNS_fixed_advance_pc => {
                    let advance = input.read_u16()?;
                    Ok(LineInstruction::FixedAddPc(advance))
                }

                constants::DW_LNS_set_prologue_end => Ok(LineInstruction::SetPrologueEnd),

                constants::DW_LNS_set_epilogue_begin => Ok(LineInstruction::SetEpilogueBegin),

                constants::DW_LNS_set_isa => {
                    let isa = input.read_uleb128()?;
                    Ok(LineInstruction::SetIsa(isa))
                }

                otherwise => {
                    let mut opcode_lengths = header.standard_opcode_lengths().clone();
                    opcode_lengths.skip(R::Offset::from_u8(opcode - 1))?;
                    let num_args = opcode_lengths.read_u8()? as usize;
                    match num_args {
                        0 => Ok(LineInstruction::UnknownStandard0(otherwise)),
                        1 => {
                            let arg = input.read_uleb128()?;
                            Ok(LineInstruction::UnknownStandard1(otherwise, arg))
                        }
                        _ => {
                            let mut args = input.clone();
                            for _ in 0..num_args {
                                input.read_uleb128()?;
                            }
                            let len = input.offset_from(&args);
                            args.truncate(len)?;
                            Ok(LineInstruction::UnknownStandardN(otherwise, args))
                        }
                    }
                }
            }
        }
    }
}

impl<R, Offset> fmt::Display for LineInstruction<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    fn fmt(&self, f: &mut fmt::Formatter) -> result::Result<(), fmt::Error> {
        match *self {
            LineInstruction::Special(opcode) => write!(f, "Special opcode {}", opcode),
            LineInstruction::Copy => write!(f, "{}", constants::DW_LNS_copy),
            LineInstruction::AdvancePc(advance) => {
                write!(f, "{} by {}", constants::DW_LNS_advance_pc, advance)
            }
            LineInstruction::AdvanceLine(increment) => {
                write!(f, "{} by {}", constants::DW_LNS_advance_line, increment)
            }
            LineInstruction::SetFile(file) => {
                write!(f, "{} to {}", constants::DW_LNS_set_file, file)
            }
            LineInstruction::SetColumn(column) => {
                write!(f, "{} to {}", constants::DW_LNS_set_column, column)
            }
            LineInstruction::NegateStatement => write!(f, "{}", constants::DW_LNS_negate_stmt),
            LineInstruction::SetBasicBlock => write!(f, "{}", constants::DW_LNS_set_basic_block),
            LineInstruction::ConstAddPc => write!(f, "{}", constants::DW_LNS_const_add_pc),
            LineInstruction::FixedAddPc(advance) => {
                write!(f, "{} by {}", constants::DW_LNS_fixed_advance_pc, advance)
            }
            LineInstruction::SetPrologueEnd => write!(f, "{}", constants::DW_LNS_set_prologue_end),
            LineInstruction::SetEpilogueBegin => {
                write!(f, "{}", constants::DW_LNS_set_epilogue_begin)
            }
            LineInstruction::SetIsa(isa) => write!(f, "{} to {}", constants::DW_LNS_set_isa, isa),
            LineInstruction::UnknownStandard0(opcode) => write!(f, "Unknown {}", opcode),
            LineInstruction::UnknownStandard1(opcode, arg) => {
                write!(f, "Unknown {} with operand {}", opcode, arg)
            }
            LineInstruction::UnknownStandardN(opcode, ref args) => {
                write!(f, "Unknown {} with operands {:?}", opcode, args)
            }
            LineInstruction::EndSequence => write!(f, "{}", constants::DW_LNE_end_sequence),
            LineInstruction::SetAddress(address) => {
                write!(f, "{} to {}", constants::DW_LNE_set_address, address)
            }
            LineInstruction::DefineFile(_) => write!(f, "{}", constants::DW_LNE_define_file),
            LineInstruction::SetDiscriminator(discr) => {
                write!(f, "{} to {}", constants::DW_LNE_set_discriminator, discr)
            }
            LineInstruction::UnknownExtended(opcode, _) => write!(f, "Unknown {}", opcode),
        }
    }
}

/// Deprecated. `OpcodesIter` has been renamed to `LineInstructions`.
#[deprecated(note = "OpcodesIter has been renamed to LineInstructions, use that instead.")]
pub type OpcodesIter<R> = LineInstructions<R>;

/// An iterator yielding parsed instructions.
///
/// See
/// [`LineProgramHeader::instructions`](./struct.LineProgramHeader.html#method.instructions)
/// for more details.
#[derive(Clone, Debug)]
pub struct LineInstructions<R: Reader> {
    input: R,
}

impl<R: Reader> LineInstructions<R> {
    fn remove_trailing(&self, other: &LineInstructions<R>) -> Result<LineInstructions<R>> {
        let offset = other.input.offset_from(&self.input);
        let mut input = self.input.clone();
        input.truncate(offset)?;
        Ok(LineInstructions { input })
    }
}

impl<R: Reader> LineInstructions<R> {
    /// Advance the iterator and return the next instruction.
    ///
    /// Returns the newly parsed instruction as `Ok(Some(instruction))`. Returns
    /// `Ok(None)` when iteration is complete and all instructions have already been
    /// parsed and yielded. If an error occurs while parsing the next attribute,
    /// then this error is returned as `Err(e)`, and all subsequent calls return
    /// `Ok(None)`.
    ///
    /// Unfortunately, the `header` parameter means that this cannot be a
    /// `FallibleIterator`.
    #[allow(clippy::inline_always)]
    #[inline(always)]
    pub fn next_instruction(
        &mut self,
        header: &LineProgramHeader<R>,
    ) -> Result<Option<LineInstruction<R>>> {
        if self.input.is_empty() {
            return Ok(None);
        }

        match LineInstruction::parse(header, &mut self.input) {
            Ok(instruction) => Ok(Some(instruction)),
            Err(e) => {
                self.input.empty();
                Err(e)
            }
        }
    }
}

/// Deprecated. `LineNumberRow` has been renamed to `LineRow`.
#[deprecated(note = "LineNumberRow has been renamed to LineRow, use that instead.")]
pub type LineNumberRow = LineRow;

/// A row in the line number program's resulting matrix.
///
/// Each row is a copy of the registers of the state machine, as defined in section 6.2.2.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct LineRow {
    address: Wrapping<u64>,
    op_index: Wrapping<u64>,
    file: u64,
    line: Wrapping<u64>,
    column: u64,
    is_stmt: bool,
    basic_block: bool,
    end_sequence: bool,
    prologue_end: bool,
    epilogue_begin: bool,
    isa: u64,
    discriminator: u64,
}

impl LineRow {
    /// Create a line number row in the initial state for the given program.
    pub fn new<R: Reader>(header: &LineProgramHeader<R>) -> Self {
        LineRow {
            // "At the beginning of each sequence within a line number program, the
            // state of the registers is:" -- Section 6.2.2
            address: Wrapping(0),
            op_index: Wrapping(0),
            file: 1,
            line: Wrapping(1),
            column: 0,
            // "determined by default_is_stmt in the line number program header"
            is_stmt: header.line_encoding.default_is_stmt,
            basic_block: false,
            end_sequence: false,
            prologue_end: false,
            epilogue_begin: false,
            // "The isa value 0 specifies that the instruction set is the
            // architecturally determined default instruction set. This may be fixed
            // by the ABI, or it may be specified by other means, for example, by
            // the object file description."
            isa: 0,
            discriminator: 0,
        }
    }

    /// "The program-counter value corresponding to a machine instruction
    /// generated by the compiler."
    #[inline]
    pub fn address(&self) -> u64 {
        self.address.0
    }

    /// > An unsigned integer representing the index of an operation within a VLIW
    /// > instruction. The index of the first operation is 0. For non-VLIW
    /// > architectures, this register will always be 0.
    /// >
    /// > The address and op_index registers, taken together, form an operation
    /// > pointer that can reference any individual operation with the
    /// > instruction stream.
    #[inline]
    pub fn op_index(&self) -> u64 {
        self.op_index.0
    }

    /// "An unsigned integer indicating the identity of the source file
    /// corresponding to a machine instruction."
    #[inline]
    pub fn file_index(&self) -> u64 {
        self.file
    }

    /// The source file corresponding to the current machine instruction.
    #[inline]
    pub fn file<'header, R: Reader>(
        &self,
        header: &'header LineProgramHeader<R>,
    ) -> Option<&'header FileEntry<R>> {
        header.file(self.file)
    }

    /// "An unsigned integer indicating a source line number. Lines are numbered
    /// beginning at 1. The compiler may emit the value 0 in cases where an
    /// instruction cannot be attributed to any source line."
    #[inline]
    pub fn line(&self) -> Option<u64> {
        if self.line.0 == 0 {
            None
        } else {
            Some(self.line.0)
        }
    }

    /// "An unsigned integer indicating a column number within a source
    /// line. Columns are numbered beginning at 1. The value 0 is reserved to
    /// indicate that a statement begins at the “left edge” of the line."
    #[inline]
    pub fn column(&self) -> ColumnType {
        if self.column == 0 {
            ColumnType::LeftEdge
        } else {
            ColumnType::Column(self.column)
        }
    }

    /// "A boolean indicating that the current instruction is a recommended
    /// breakpoint location. A recommended breakpoint location is intended to
    /// “represent” a line, a statement and/or a semantically distinct subpart
    /// of a statement."
    #[inline]
    pub fn is_stmt(&self) -> bool {
        self.is_stmt
    }

    /// "A boolean indicating that the current instruction is the beginning of a
    /// basic block."
    #[inline]
    pub fn basic_block(&self) -> bool {
        self.basic_block
    }

    /// "A boolean indicating that the current address is that of the first byte
    /// after the end of a sequence of target machine instructions. end_sequence
    /// terminates a sequence of lines; therefore other information in the same
    /// row is not meaningful."
    #[inline]
    pub fn end_sequence(&self) -> bool {
        self.end_sequence
    }

    /// "A boolean indicating that the current address is one (of possibly many)
    /// where execution should be suspended for an entry breakpoint of a
    /// function."
    #[inline]
    pub fn prologue_end(&self) -> bool {
        self.prologue_end
    }

    /// "A boolean indicating that the current address is one (of possibly many)
    /// where execution should be suspended for an exit breakpoint of a
    /// function."
    #[inline]
    pub fn epilogue_begin(&self) -> bool {
        self.epilogue_begin
    }

    /// Tag for the current instruction set architecture.
    ///
    /// > An unsigned integer whose value encodes the applicable instruction set
    /// > architecture for the current instruction.
    /// >
    /// > The encoding of instruction sets should be shared by all users of a
    /// > given architecture. It is recommended that this encoding be defined by
    /// > the ABI authoring committee for each architecture.
    #[inline]
    pub fn isa(&self) -> u64 {
        self.isa
    }

    /// "An unsigned integer identifying the block to which the current
    /// instruction belongs. Discriminator values are assigned arbitrarily by
    /// the DWARF producer and serve to distinguish among multiple blocks that
    /// may all be associated with the same source file, line, and column. Where
    /// only one block exists for a given source position, the discriminator
    /// value should be zero."
    #[inline]
    pub fn discriminator(&self) -> u64 {
        self.discriminator
    }

    /// Execute the given instruction, and return true if a new row in the
    /// line number matrix needs to be generated.
    ///
    /// Unknown opcodes are treated as no-ops.
    #[inline]
    pub fn execute<R, Program>(
        &mut self,
        instruction: LineInstruction<R>,
        program: &mut Program,
    ) -> bool
    where
        Program: LineProgram<R>,
        R: Reader,
    {
        match instruction {
            LineInstruction::Special(opcode) => {
                self.exec_special_opcode(opcode, program.header());
                true
            }

            LineInstruction::Copy => true,

            LineInstruction::AdvancePc(operation_advance) => {
                self.apply_operation_advance(operation_advance, program.header());
                false
            }

            LineInstruction::AdvanceLine(line_increment) => {
                self.apply_line_advance(line_increment);
                false
            }

            LineInstruction::SetFile(file) => {
                self.file = file;
                false
            }

            LineInstruction::SetColumn(column) => {
                self.column = column;
                false
            }

            LineInstruction::NegateStatement => {
                self.is_stmt = !self.is_stmt;
                false
            }

            LineInstruction::SetBasicBlock => {
                self.basic_block = true;
                false
            }

            LineInstruction::ConstAddPc => {
                let adjusted = self.adjust_opcode(255, program.header());
                let operation_advance = adjusted / program.header().line_encoding.line_range;
                self.apply_operation_advance(u64::from(operation_advance), program.header());
                false
            }

            LineInstruction::FixedAddPc(operand) => {
                self.address += Wrapping(u64::from(operand));
                self.op_index.0 = 0;
                false
            }

            LineInstruction::SetPrologueEnd => {
                self.prologue_end = true;
                false
            }

            LineInstruction::SetEpilogueBegin => {
                self.epilogue_begin = true;
                false
            }

            LineInstruction::SetIsa(isa) => {
                self.isa = isa;
                false
            }

            LineInstruction::EndSequence => {
                self.end_sequence = true;
                true
            }

            LineInstruction::SetAddress(address) => {
                self.address.0 = address;
                self.op_index.0 = 0;
                false
            }

            LineInstruction::DefineFile(entry) => {
                program.add_file(entry);
                false
            }

            LineInstruction::SetDiscriminator(discriminator) => {
                self.discriminator = discriminator;
                false
            }

            // Compatibility with future opcodes.
            LineInstruction::UnknownStandard0(_)
            | LineInstruction::UnknownStandard1(_, _)
            | LineInstruction::UnknownStandardN(_, _)
            | LineInstruction::UnknownExtended(_, _) => false,
        }
    }

    /// Perform any reset that was required after copying the previous row.
    #[inline]
    pub fn reset<R: Reader>(&mut self, header: &LineProgramHeader<R>) {
        if self.end_sequence {
            // Previous instruction was EndSequence, so reset everything
            // as specified in Section 6.2.5.3.
            *self = Self::new(header);
        } else {
            // Previous instruction was one of:
            // - Special - specified in Section 6.2.5.1, steps 4-7
            // - Copy - specified in Section 6.2.5.2
            // The reset behaviour is the same in both cases.
            self.discriminator = 0;
            self.basic_block = false;
            self.prologue_end = false;
            self.epilogue_begin = false;
        }
    }

    /// Step 1 of section 6.2.5.1
    fn apply_line_advance(&mut self, line_increment: i64) {
        if line_increment < 0 {
            let decrement = -line_increment as u64;
            if decrement <= self.line.0 {
                self.line.0 -= decrement;
            } else {
                self.line.0 = 0;
            }
        } else {
            self.line += Wrapping(line_increment as u64);
        }
    }

    /// Step 2 of section 6.2.5.1
    fn apply_operation_advance<R: Reader>(
        &mut self,
        operation_advance: u64,
        header: &LineProgramHeader<R>,
    ) {
        let operation_advance = Wrapping(operation_advance);

        let minimum_instruction_length = u64::from(header.line_encoding.minimum_instruction_length);
        let minimum_instruction_length = Wrapping(minimum_instruction_length);

        let maximum_operations_per_instruction =
            u64::from(header.line_encoding.maximum_operations_per_instruction);
        let maximum_operations_per_instruction = Wrapping(maximum_operations_per_instruction);

        if maximum_operations_per_instruction.0 == 1 {
            self.address += minimum_instruction_length * operation_advance;
            self.op_index.0 = 0;
        } else {
            let op_index_with_advance = self.op_index + operation_advance;
            self.address += minimum_instruction_length
                * (op_index_with_advance / maximum_operations_per_instruction);
            self.op_index = op_index_with_advance % maximum_operations_per_instruction;
        }
    }

    #[inline]
    fn adjust_opcode<R: Reader>(&self, opcode: u8, header: &LineProgramHeader<R>) -> u8 {
        opcode - header.opcode_base
    }

    /// Section 6.2.5.1
    fn exec_special_opcode<R: Reader>(&mut self, opcode: u8, header: &LineProgramHeader<R>) {
        let adjusted_opcode = self.adjust_opcode(opcode, header);

        let line_range = header.line_encoding.line_range;
        let line_advance = adjusted_opcode % line_range;
        let operation_advance = adjusted_opcode / line_range;

        // Step 1
        let line_base = i64::from(header.line_encoding.line_base);
        self.apply_line_advance(line_base + i64::from(line_advance));

        // Step 2
        self.apply_operation_advance(u64::from(operation_advance), header);
    }
}

/// The type of column that a row is referring to.
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub enum ColumnType {
    /// The `LeftEdge` means that the statement begins at the start of the new
    /// line.
    LeftEdge,
    /// A column number, whose range begins at 1.
    Column(u64),
}

/// Deprecated. `LineNumberSequence` has been renamed to `LineSequence`.
#[deprecated(note = "LineNumberSequence has been renamed to LineSequence, use that instead.")]
pub type LineNumberSequence<R> = LineSequence<R>;

/// A sequence within a line number program.  A sequence, as defined in section
/// 6.2.5 of the standard, is a linear subset of a line number program within
/// which addresses are monotonically increasing.
#[derive(Clone, Debug)]
pub struct LineSequence<R: Reader> {
    /// The first address that is covered by this sequence within the line number
    /// program.
    pub start: u64,
    /// The first address that is *not* covered by this sequence within the line
    /// number program.
    pub end: u64,
    instructions: LineInstructions<R>,
}

/// Deprecated. `LineNumberProgramHeader` has been renamed to `LineProgramHeader`.
#[deprecated(
    note = "LineNumberProgramHeader has been renamed to LineProgramHeader, use that instead."
)]
pub type LineNumberProgramHeader<R, Offset> = LineProgramHeader<R, Offset>;

/// A header for a line number program in the `.debug_line` section, as defined
/// in section 6.2.4 of the standard.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct LineProgramHeader<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    encoding: Encoding,
    offset: DebugLineOffset<Offset>,
    unit_length: Offset,

    header_length: Offset,

    line_encoding: LineEncoding,

    /// "The number assigned to the first special opcode."
    opcode_base: u8,

    /// "This array specifies the number of LEB128 operands for each of the
    /// standard opcodes. The first element of the array corresponds to the
    /// opcode whose value is 1, and the last element corresponds to the opcode
    /// whose value is `opcode_base - 1`."
    standard_opcode_lengths: R,

    /// "A sequence of directory entry format descriptions."
    directory_entry_format: Vec<FileEntryFormat>,

    /// > Entries in this sequence describe each path that was searched for
    /// > included source files in this compilation. (The paths include those
    /// > directories specified explicitly by the user for the compiler to search
    /// > and those the compiler searches without explicit direction.) Each path
    /// > entry is either a full path name or is relative to the current directory
    /// > of the compilation.
    /// >
    /// > The last entry is followed by a single null byte.
    include_directories: Vec<AttributeValue<R, Offset>>,

    /// "A sequence of file entry format descriptions."
    file_name_entry_format: Vec<FileEntryFormat>,

    /// "Entries in this sequence describe source files that contribute to the
    /// line number information for this compilation unit or is used in other
    /// contexts."
    file_names: Vec<FileEntry<R, Offset>>,

    /// The encoded line program instructions.
    program_buf: R,

    /// The current directory of the compilation.
    comp_dir: Option<R>,

    /// The primary source file.
    comp_file: Option<FileEntry<R, Offset>>,
}

impl<R, Offset> LineProgramHeader<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    /// Return the offset of the line number program header in the `.debug_line` section.
    pub fn offset(&self) -> DebugLineOffset<R::Offset> {
        self.offset
    }

    /// Return the length of the line number program and header, not including
    /// the length of the encoded length itself.
    pub fn unit_length(&self) -> R::Offset {
        self.unit_length
    }

    /// Return the encoding parameters for this header's line program.
    pub fn encoding(&self) -> Encoding {
        self.encoding
    }

    /// Get the version of this header's line program.
    pub fn version(&self) -> u16 {
        self.encoding.version
    }

    /// Get the length of the encoded line number program header, not including
    /// the length of the encoded length itself.
    pub fn header_length(&self) -> R::Offset {
        self.header_length
    }

    /// Get the size in bytes of a target machine address.
    pub fn address_size(&self) -> u8 {
        self.encoding.address_size
    }

    /// Whether this line program is encoded in 64- or 32-bit DWARF.
    pub fn format(&self) -> Format {
        self.encoding.format
    }

    /// Get the line encoding parameters for this header's line program.
    pub fn line_encoding(&self) -> LineEncoding {
        self.line_encoding
    }

    /// Get the minimum instruction length any instruction in this header's line
    /// program may have.
    pub fn minimum_instruction_length(&self) -> u8 {
        self.line_encoding.minimum_instruction_length
    }

    /// Get the maximum number of operations each instruction in this header's
    /// line program may have.
    pub fn maximum_operations_per_instruction(&self) -> u8 {
        self.line_encoding.maximum_operations_per_instruction
    }

    /// Get the default value of the `is_stmt` register for this header's line
    /// program.
    pub fn default_is_stmt(&self) -> bool {
        self.line_encoding.default_is_stmt
    }

    /// Get the line base for this header's line program.
    pub fn line_base(&self) -> i8 {
        self.line_encoding.line_base
    }

    /// Get the line range for this header's line program.
    pub fn line_range(&self) -> u8 {
        self.line_encoding.line_range
    }

    /// Get opcode base for this header's line program.
    pub fn opcode_base(&self) -> u8 {
        self.opcode_base
    }

    /// An array of `u8` that specifies the number of LEB128 operands for
    /// each of the standard opcodes.
    pub fn standard_opcode_lengths(&self) -> &R {
        &self.standard_opcode_lengths
    }

    /// Get the format of a directory entry.
    pub fn directory_entry_format(&self) -> &[FileEntryFormat] {
        &self.directory_entry_format[..]
    }

    /// Get the set of include directories for this header's line program.
    ///
    /// For DWARF version <= 4, the compilation's current directory is not included
    /// in the return value, but is implicitly considered to be in the set per spec.
    pub fn include_directories(&self) -> &[AttributeValue<R, Offset>] {
        &self.include_directories[..]
    }

    /// The include directory with the given directory index.
    ///
    /// A directory index of 0 corresponds to the compilation unit directory.
    pub fn directory(&self, directory: u64) -> Option<AttributeValue<R, Offset>> {
        if self.encoding.version <= 4 {
            if directory == 0 {
                self.comp_dir.clone().map(AttributeValue::String)
            } else {
                let directory = directory as usize - 1;
                self.include_directories.get(directory).cloned()
            }
        } else {
            self.include_directories.get(directory as usize).cloned()
        }
    }

    /// Get the format of a file name entry.
    pub fn file_name_entry_format(&self) -> &[FileEntryFormat] {
        &self.file_name_entry_format[..]
    }

    /// Return true if the file entries may have valid timestamps.
    ///
    /// Only returns false if we definitely know that all timestamp fields
    /// are invalid.
    pub fn file_has_timestamp(&self) -> bool {
        self.encoding.version <= 4
            || self
                .file_name_entry_format
                .iter()
                .any(|x| x.content_type == constants::DW_LNCT_timestamp)
    }

    /// Return true if the file entries may have valid sizes.
    ///
    /// Only returns false if we definitely know that all size fields
    /// are invalid.
    pub fn file_has_size(&self) -> bool {
        self.encoding.version <= 4
            || self
                .file_name_entry_format
                .iter()
                .any(|x| x.content_type == constants::DW_LNCT_size)
    }

    /// Return true if the file name entry format contains an MD5 field.
    pub fn file_has_md5(&self) -> bool {
        self.file_name_entry_format
            .iter()
            .any(|x| x.content_type == constants::DW_LNCT_MD5)
    }

    /// Get the list of source files that appear in this header's line program.
    pub fn file_names(&self) -> &[FileEntry<R, Offset>] {
        &self.file_names[..]
    }

    /// The source file with the given file index.
    ///
    /// A file index of 0 corresponds to the compilation unit file.
    /// Note that a file index of 0 is invalid for DWARF version <= 4,
    /// but we support it anyway.
    pub fn file(&self, file: u64) -> Option<&FileEntry<R, Offset>> {
        if self.encoding.version <= 4 {
            if file == 0 {
                self.comp_file.as_ref()
            } else {
                let file = file as usize - 1;
                self.file_names.get(file)
            }
        } else {
            self.file_names.get(file as usize)
        }
    }

    /// Get the raw, un-parsed `EndianSlice` containing this header's line number
    /// program.
    ///
    /// ```
    /// # fn foo() {
    /// use gimli::{LineProgramHeader, EndianSlice, NativeEndian};
    ///
    /// fn get_line_number_program_header<'a>() -> LineProgramHeader<EndianSlice<'a, NativeEndian>> {
    ///     // Get a line number program header from some offset in a
    ///     // `.debug_line` section...
    /// #   unimplemented!()
    /// }
    ///
    /// let header = get_line_number_program_header();
    /// let raw_program = header.raw_program_buf();
    /// println!("The length of the raw program in bytes is {}", raw_program.len());
    /// # }
    /// ```
    pub fn raw_program_buf(&self) -> R {
        self.program_buf.clone()
    }

    /// Iterate over the instructions in this header's line number program, parsing
    /// them as we go.
    pub fn instructions(&self) -> LineInstructions<R> {
        LineInstructions {
            input: self.program_buf.clone(),
        }
    }

    fn parse(
        input: &mut R,
        offset: DebugLineOffset<Offset>,
        mut address_size: u8,
        mut comp_dir: Option<R>,
        comp_name: Option<R>,
    ) -> Result<LineProgramHeader<R, Offset>> {
        let (unit_length, format) = input.read_initial_length()?;
        let rest = &mut input.split(unit_length)?;

        let version = rest.read_u16()?;
        if version < 2 || version > 5 {
            return Err(Error::UnknownVersion(u64::from(version)));
        }

        if version >= 5 {
            address_size = rest.read_u8()?;
            let segment_selector_size = rest.read_u8()?;
            if segment_selector_size != 0 {
                return Err(Error::UnsupportedSegmentSize);
            }
        }

        let encoding = Encoding {
            format,
            version,
            address_size,
        };

        let header_length = rest.read_length(format)?;

        let mut program_buf = rest.clone();
        program_buf.skip(header_length)?;
        rest.truncate(header_length)?;

        let minimum_instruction_length = rest.read_u8()?;
        if minimum_instruction_length == 0 {
            return Err(Error::MinimumInstructionLengthZero);
        }

        // This field did not exist before DWARF 4, but is specified to be 1 for
        // non-VLIW architectures, which makes it a no-op.
        let maximum_operations_per_instruction = if version >= 4 { rest.read_u8()? } else { 1 };
        if maximum_operations_per_instruction == 0 {
            return Err(Error::MaximumOperationsPerInstructionZero);
        }

        let default_is_stmt = rest.read_u8()? != 0;
        let line_base = rest.read_i8()?;
        let line_range = rest.read_u8()?;
        if line_range == 0 {
            return Err(Error::LineRangeZero);
        }
        let line_encoding = LineEncoding {
            minimum_instruction_length,
            maximum_operations_per_instruction,
            default_is_stmt,
            line_base,
            line_range,
        };

        let opcode_base = rest.read_u8()?;
        if opcode_base == 0 {
            return Err(Error::OpcodeBaseZero);
        }

        let standard_opcode_count = R::Offset::from_u8(opcode_base - 1);
        let standard_opcode_lengths = rest.split(standard_opcode_count)?;

        let directory_entry_format;
        let mut include_directories = Vec::new();
        if version <= 4 {
            directory_entry_format = Vec::new();
            loop {
                let directory = rest.read_null_terminated_slice()?;
                if directory.is_empty() {
                    break;
                }
                include_directories.push(AttributeValue::String(directory));
            }
        } else {
            comp_dir = None;
            directory_entry_format = FileEntryFormat::parse(rest)?;
            let count = rest.read_uleb128()?;
            for _ in 0..count {
                include_directories.push(parse_directory_v5(
                    rest,
                    encoding,
                    &directory_entry_format,
                )?);
            }
        }

        let comp_file;
        let file_name_entry_format;
        let mut file_names = Vec::new();
        if version <= 4 {
            comp_file = comp_name.map(|name| FileEntry {
                path_name: AttributeValue::String(name),
                directory_index: 0,
                timestamp: 0,
                size: 0,
                md5: [0; 16],
            });

            file_name_entry_format = Vec::new();
            loop {
                let path_name = rest.read_null_terminated_slice()?;
                if path_name.is_empty() {
                    break;
                }
                file_names.push(FileEntry::parse(rest, path_name)?);
            }
        } else {
            comp_file = None;
            file_name_entry_format = FileEntryFormat::parse(rest)?;
            let count = rest.read_uleb128()?;
            for _ in 0..count {
                file_names.push(parse_file_v5(rest, encoding, &file_name_entry_format)?);
            }
        }

        let header = LineProgramHeader {
            encoding,
            offset,
            unit_length,
            header_length,
            line_encoding,
            opcode_base,
            standard_opcode_lengths,
            directory_entry_format,
            include_directories,
            file_name_entry_format,
            file_names,
            program_buf,
            comp_dir,
            comp_file,
        };
        Ok(header)
    }
}

/// Deprecated. `IncompleteLineNumberProgram` has been renamed to `IncompleteLineProgram`.
#[deprecated(
    note = "IncompleteLineNumberProgram has been renamed to IncompleteLineProgram, use that instead."
)]
pub type IncompleteLineNumberProgram<R, Offset> = IncompleteLineProgram<R, Offset>;

/// A line number program that has not been run to completion.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct IncompleteLineProgram<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    header: LineProgramHeader<R, Offset>,
}

impl<R, Offset> IncompleteLineProgram<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    /// Retrieve the `LineProgramHeader` for this program.
    pub fn header(&self) -> &LineProgramHeader<R, Offset> {
        &self.header
    }

    /// Construct a new `LineRows` for executing this program to iterate
    /// over rows in the line information matrix.
    pub fn rows(self) -> OneShotLineRows<R, Offset> {
        OneShotLineRows::new(self)
    }

    /// Execute the line number program, completing the `IncompleteLineProgram`
    /// into a `CompleteLineProgram` and producing an array of sequences within
    /// the line number program that can later be used with
    /// `CompleteLineProgram::resume_from`.
    ///
    /// ```
    /// # fn foo() {
    /// use gimli::{IncompleteLineProgram, EndianSlice, NativeEndian};
    ///
    /// fn get_line_number_program<'a>() -> IncompleteLineProgram<EndianSlice<'a, NativeEndian>> {
    ///     // Get a line number program from some offset in a
    ///     // `.debug_line` section...
    /// #   unimplemented!()
    /// }
    ///
    /// let program = get_line_number_program();
    /// let (program, sequences) = program.sequences().unwrap();
    /// println!("There are {} sequences in this line number program", sequences.len());
    /// # }
    /// ```
    #[allow(clippy::type_complexity)]
    pub fn sequences(self) -> Result<(CompleteLineProgram<R, Offset>, Vec<LineSequence<R>>)> {
        let mut sequences = Vec::new();
        let mut rows = self.rows();
        let mut instructions = rows.instructions.clone();
        let mut sequence_start_addr = None;
        loop {
            let sequence_end_addr;
            if rows.next_row()?.is_none() {
                break;
            }

            let row = &rows.row;
            if row.end_sequence() {
                sequence_end_addr = row.address();
            } else if sequence_start_addr.is_none() {
                sequence_start_addr = Some(row.address());
                continue;
            } else {
                continue;
            }

            // We just finished a sequence.
            sequences.push(LineSequence {
                // In theory one could have multiple DW_LNE_end_sequence instructions
                // in a row.
                start: sequence_start_addr.unwrap_or(0),
                end: sequence_end_addr,
                instructions: instructions.remove_trailing(&rows.instructions)?,
            });
            sequence_start_addr = None;
            instructions = rows.instructions.clone();
        }

        let program = CompleteLineProgram {
            header: rows.program.header,
        };
        Ok((program, sequences))
    }
}

/// Deprecated. `CompleteLineNumberProgram` has been renamed to `CompleteLineProgram`.
#[deprecated(
    note = "CompleteLineNumberProgram has been renamed to CompleteLineProgram, use that instead."
)]
pub type CompleteLineNumberProgram<R, Offset> = CompleteLineProgram<R, Offset>;

/// A line number program that has previously been run to completion.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct CompleteLineProgram<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    header: LineProgramHeader<R, Offset>,
}

impl<R, Offset> CompleteLineProgram<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    /// Retrieve the `LineProgramHeader` for this program.
    pub fn header(&self) -> &LineProgramHeader<R, Offset> {
        &self.header
    }

    /// Construct a new `LineRows` for executing the subset of the line
    /// number program identified by 'sequence' and  generating the line information
    /// matrix.
    ///
    /// ```
    /// # fn foo() {
    /// use gimli::{IncompleteLineProgram, EndianSlice, NativeEndian};
    ///
    /// fn get_line_number_program<'a>() -> IncompleteLineProgram<EndianSlice<'a, NativeEndian>> {
    ///     // Get a line number program from some offset in a
    ///     // `.debug_line` section...
    /// #   unimplemented!()
    /// }
    ///
    /// let program = get_line_number_program();
    /// let (program, sequences) = program.sequences().unwrap();
    /// for sequence in &sequences {
    ///     let mut sm = program.resume_from(sequence);
    /// }
    /// # }
    /// ```
    pub fn resume_from<'program>(
        &'program self,
        sequence: &LineSequence<R>,
    ) -> ResumedLineRows<'program, R, Offset> {
        ResumedLineRows::resume(self, sequence)
    }
}

/// An entry in the `LineProgramHeader`'s `file_names` set.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct FileEntry<R, Offset = <R as Reader>::Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    path_name: AttributeValue<R, Offset>,
    directory_index: u64,
    timestamp: u64,
    size: u64,
    md5: [u8; 16],
}

impl<R, Offset> FileEntry<R, Offset>
where
    R: Reader<Offset = Offset>,
    Offset: ReaderOffset,
{
    // version 2-4
    fn parse(input: &mut R, path_name: R) -> Result<FileEntry<R, Offset>> {
        let directory_index = input.read_uleb128()?;
        let timestamp = input.read_uleb128()?;
        let size = input.read_uleb128()?;

        let entry = FileEntry {
            path_name: AttributeValue::String(path_name),
            directory_index,
            timestamp,
            size,
            md5: [0; 16],
        };

        Ok(entry)
    }

    /// > A slice containing the full or relative path name of
    /// > a source file. If the entry contains a file name or a relative path
    /// > name, the file is located relative to either the compilation directory
    /// > (as specified by the DW_AT_comp_dir attribute given in the compilation
    /// > unit) or one of the directories in the include_directories section.
    pub fn path_name(&self) -> AttributeValue<R, Offset> {
        self.path_name.clone()
    }

    /// > An unsigned LEB128 number representing the directory index of the
    /// > directory in which the file was found.
    /// >
    /// > ...
    /// >
    /// > The directory index represents an entry in the include_directories
    /// > section of the line number program header. The index is 0 if the file
    /// > was found in the current directory of the compilation, 1 if it was found
    /// > in the first directory in the include_directories section, and so
    /// > on. The directory index is ignored for file names that represent full
    /// > path names.
    pub fn directory_index(&self) -> u64 {
        self.directory_index
    }

    /// Get this file's directory.
    ///
    /// A directory index of 0 corresponds to the compilation unit directory.
    pub fn directory(&self, header: &LineProgramHeader<R>) -> Option<AttributeValue<R, Offset>> {
        header.directory(self.directory_index)
    }

    /// The implementation-defined time of last modification of the file,
    /// or 0 if not available.
    pub fn timestamp(&self) -> u64 {
        self.timestamp
    }

    /// "An unsigned LEB128 number representing the time of last modification of
    /// the file, or 0 if not available."
    // Terminology changed in DWARF version 5.
    #[doc(hidden)]
    pub fn last_modification(&self) -> u64 {
        self.timestamp
    }

    /// The size of the file in bytes, or 0 if not available.
    pub fn size(&self) -> u64 {
        self.size
    }

    /// "An unsigned LEB128 number representing the length in bytes of the file,
    /// or 0 if not available."
    // Terminology changed in DWARF version 5.
    #[doc(hidden)]
    pub fn length(&self) -> u64 {
        self.size
    }

    /// A 16-byte MD5 digest of the file contents.
    ///
    /// Only valid if `LineProgramHeader::file_has_md5` returns `true`.
    pub fn md5(&self) -> &[u8; 16] {
        &self.md5
    }
}

/// The format of a component of an include directory or file name entry.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct FileEntryFormat {
    /// The type of information that is represented by the component.
    pub content_type: constants::DwLnct,

    /// The encoding form of the component value.
    pub form: constants::DwForm,
}

impl FileEntryFormat {
    fn parse<R: Reader>(input: &mut R) -> Result<Vec<FileEntryFormat>> {
        let format_count = input.read_u8()? as usize;
        let mut format = Vec::with_capacity(format_count);
        let mut path_count = 0;
        for _ in 0..format_count {
            let content_type = input.read_uleb128()?;
            let content_type = if content_type > u64::from(u16::max_value()) {
                constants::DwLnct(u16::max_value())
            } else {
                constants::DwLnct(content_type as u16)
            };
            if content_type == constants::DW_LNCT_path {
                path_count += 1;
            }

            let form = constants::DwForm(input.read_uleb128_u16()?);

            format.push(FileEntryFormat { content_type, form });
        }
        if path_count != 1 {
            return Err(Error::MissingFileEntryFormatPath);
        }
        Ok(format)
    }
}

fn parse_directory_v5<R: Reader>(
    input: &mut R,
    encoding: Encoding,
    formats: &[FileEntryFormat],
) -> Result<AttributeValue<R>> {
    let mut path_name = None;

    for format in formats {
        let value = parse_attribute(input, encoding, format.form)?;
        if format.content_type == constants::DW_LNCT_path {
            path_name = Some(value);
        }
    }

    Ok(path_name.unwrap())
}

fn parse_file_v5<R: Reader>(
    input: &mut R,
    encoding: Encoding,
    formats: &[FileEntryFormat],
) -> Result<FileEntry<R>> {
    let mut path_name = None;
    let mut directory_index = 0;
    let mut timestamp = 0;
    let mut size = 0;
    let mut md5 = [0; 16];

    for format in formats {
        let value = parse_attribute(input, encoding, format.form)?;
        match format.content_type {
            constants::DW_LNCT_path => path_name = Some(value),
            constants::DW_LNCT_directory_index => {
                if let Some(value) = value.udata_value() {
                    directory_index = value;
                }
            }
            constants::DW_LNCT_timestamp => {
                if let Some(value) = value.udata_value() {
                    timestamp = value;
                }
            }
            constants::DW_LNCT_size => {
                if let Some(value) = value.udata_value() {
                    size = value;
                }
            }
            constants::DW_LNCT_MD5 => {
                if let AttributeValue::Block(mut value) = value {
                    if value.len().into_u64() == 16 {
                        md5 = value.read_u8_array()?;
                    }
                }
            }
            // Ignore unknown content types.
            _ => {}
        }
    }

    Ok(FileEntry {
        path_name: path_name.unwrap(),
        directory_index,
        timestamp,
        size,
        md5,
    })
}

// TODO: this should be shared with unit::parse_attribute(), but that is hard to do.
fn parse_attribute<R: Reader>(
    input: &mut R,
    encoding: Encoding,
    form: constants::DwForm,
) -> Result<AttributeValue<R>> {
    Ok(match form {
        constants::DW_FORM_block1 => {
            let len = input.read_u8().map(R::Offset::from_u8)?;
            let block = input.split(len)?;
            AttributeValue::Block(block)
        }
        constants::DW_FORM_block2 => {
            let len = input.read_u16().map(R::Offset::from_u16)?;
            let block = input.split(len)?;
            AttributeValue::Block(block)
        }
        constants::DW_FORM_block4 => {
            let len = input.read_u32().map(R::Offset::from_u32)?;
            let block = input.split(len)?;
            AttributeValue::Block(block)
        }
        constants::DW_FORM_block => {
            let len = input.read_uleb128().and_then(R::Offset::from_u64)?;
            let block = input.split(len)?;
            AttributeValue::Block(block)
        }
        constants::DW_FORM_data1 => {
            let data = input.read_u8()?;
            AttributeValue::Data1(data)
        }
        constants::DW_FORM_data2 => {
            let data = input.read_u16()?;
            AttributeValue::Data2(data)
        }
        constants::DW_FORM_data4 => {
            let data = input.read_u32()?;
            AttributeValue::Data4(data)
        }
        constants::DW_FORM_data8 => {
            let data = input.read_u64()?;
            AttributeValue::Data8(data)
        }
        constants::DW_FORM_data16 => {
            let block = input.split(R::Offset::from_u8(16))?;
            AttributeValue::Block(block)
        }
        constants::DW_FORM_udata => {
            let data = input.read_uleb128()?;
            AttributeValue::Udata(data)
        }
        constants::DW_FORM_sdata => {
            let data = input.read_sleb128()?;
            AttributeValue::Sdata(data)
        }
        constants::DW_FORM_flag => {
            let present = input.read_u8()?;
            AttributeValue::Flag(present != 0)
        }
        constants::DW_FORM_sec_offset => {
            let offset = input.read_offset(encoding.format)?;
            AttributeValue::SecOffset(offset)
        }
        constants::DW_FORM_string => {
            let string = input.read_null_terminated_slice()?;
            AttributeValue::String(string)
        }
        constants::DW_FORM_strp => {
            let offset = input.read_offset(encoding.format)?;
            AttributeValue::DebugStrRef(DebugStrOffset(offset))
        }
        constants::DW_FORM_strp_sup | constants::DW_FORM_GNU_strp_alt => {
            let offset = input.read_offset(encoding.format)?;
            AttributeValue::DebugStrRefSup(DebugStrOffset(offset))
        }
        constants::DW_FORM_line_strp => {
            let offset = input.read_offset(encoding.format)?;
            AttributeValue::DebugLineStrRef(DebugLineStrOffset(offset))
        }
        constants::DW_FORM_strx | constants::DW_FORM_GNU_str_index => {
            let index = input.read_uleb128().and_then(R::Offset::from_u64)?;
            AttributeValue::DebugStrOffsetsIndex(DebugStrOffsetsIndex(index))
        }
        constants::DW_FORM_strx1 => {
            let index = input.read_u8().map(R::Offset::from_u8)?;
            AttributeValue::DebugStrOffsetsIndex(DebugStrOffsetsIndex(index))
        }
        constants::DW_FORM_strx2 => {
            let index = input.read_u16().map(R::Offset::from_u16)?;
            AttributeValue::DebugStrOffsetsIndex(DebugStrOffsetsIndex(index))
        }
        constants::DW_FORM_strx3 => {
            let index = input.read_uint(3).and_then(R::Offset::from_u64)?;
            AttributeValue::DebugStrOffsetsIndex(DebugStrOffsetsIndex(index))
        }
        constants::DW_FORM_strx4 => {
            let index = input.read_u32().map(R::Offset::from_u32)?;
            AttributeValue::DebugStrOffsetsIndex(DebugStrOffsetsIndex(index))
        }
        _ => {
            return Err(Error::UnknownForm);
        }
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::constants;
    use crate::endianity::LittleEndian;
    use crate::read::{EndianSlice, Error};
    use crate::test_util::GimliSectionMethods;
    use core::u64;
    use core::u8;
    use test_assembler::{Endian, Label, LabelMaker, Section};

    #[test]
    fn test_parse_debug_line_32_ok() {
        #[rustfmt::skip]
        let buf = [
            // 32-bit length = 62.
            0x3e, 0x00, 0x00, 0x00,
            // Version.
            0x04, 0x00,
            // Header length = 40.
            0x28, 0x00, 0x00, 0x00,
            // Minimum instruction length.
            0x01,
            // Maximum operations per byte.
            0x01,
            // Default is_stmt.
            0x01,
            // Line base.
            0x00,
            // Line range.
            0x01,
            // Opcode base.
            0x03,
            // Standard opcode lengths for opcodes 1 .. opcode base - 1.
            0x01, 0x02,
            // Include directories = '/', 'i', 'n', 'c', '\0', '/', 'i', 'n', 'c', '2', '\0', '\0'
            0x2f, 0x69, 0x6e, 0x63, 0x00, 0x2f, 0x69, 0x6e, 0x63, 0x32, 0x00, 0x00,
            // File names
                // foo.rs
                0x66, 0x6f, 0x6f, 0x2e, 0x72, 0x73, 0x00,
                0x00,
                0x00,
                0x00,
                // bar.h
                0x62, 0x61, 0x72, 0x2e, 0x68, 0x00,
                0x01,
                0x00,
                0x00,
            // End file names.
            0x00,

            // Dummy line program data.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,

            // Dummy next line program.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
        ];

        let rest = &mut EndianSlice::new(&buf, LittleEndian);
        let comp_dir = EndianSlice::new(b"/comp_dir", LittleEndian);
        let comp_name = EndianSlice::new(b"/comp_name", LittleEndian);

        let header =
            LineProgramHeader::parse(rest, DebugLineOffset(0), 4, Some(comp_dir), Some(comp_name))
                .expect("should parse header ok");

        assert_eq!(
            *rest,
            EndianSlice::new(&buf[buf.len() - 16..], LittleEndian)
        );

        assert_eq!(header.offset, DebugLineOffset(0));
        assert_eq!(header.version(), 4);
        assert_eq!(header.minimum_instruction_length(), 1);
        assert_eq!(header.maximum_operations_per_instruction(), 1);
        assert_eq!(header.default_is_stmt(), true);
        assert_eq!(header.line_base(), 0);
        assert_eq!(header.line_range(), 1);
        assert_eq!(header.opcode_base(), 3);
        assert_eq!(header.directory(0), Some(AttributeValue::String(comp_dir)));
        assert_eq!(
            header.file(0).unwrap().path_name,
            AttributeValue::String(comp_name)
        );

        let expected_lengths = [1, 2];
        assert_eq!(header.standard_opcode_lengths().slice(), &expected_lengths);

        let expected_include_directories = [
            AttributeValue::String(EndianSlice::new(b"/inc", LittleEndian)),
            AttributeValue::String(EndianSlice::new(b"/inc2", LittleEndian)),
        ];
        assert_eq!(header.include_directories(), &expected_include_directories);

        let expected_file_names = [
            FileEntry {
                path_name: AttributeValue::String(EndianSlice::new(b"foo.rs", LittleEndian)),
                directory_index: 0,
                timestamp: 0,
                size: 0,
                md5: [0; 16],
            },
            FileEntry {
                path_name: AttributeValue::String(EndianSlice::new(b"bar.h", LittleEndian)),
                directory_index: 1,
                timestamp: 0,
                size: 0,
                md5: [0; 16],
            },
        ];
        assert_eq!(&*header.file_names(), &expected_file_names);
    }

    #[test]
    fn test_parse_debug_line_header_length_too_short() {
        #[rustfmt::skip]
        let buf = [
            // 32-bit length = 62.
            0x3e, 0x00, 0x00, 0x00,
            // Version.
            0x04, 0x00,
            // Header length = 20. TOO SHORT!!!
            0x15, 0x00, 0x00, 0x00,
            // Minimum instruction length.
            0x01,
            // Maximum operations per byte.
            0x01,
            // Default is_stmt.
            0x01,
            // Line base.
            0x00,
            // Line range.
            0x01,
            // Opcode base.
            0x03,
            // Standard opcode lengths for opcodes 1 .. opcode base - 1.
            0x01, 0x02,
            // Include directories = '/', 'i', 'n', 'c', '\0', '/', 'i', 'n', 'c', '2', '\0', '\0'
            0x2f, 0x69, 0x6e, 0x63, 0x00, 0x2f, 0x69, 0x6e, 0x63, 0x32, 0x00, 0x00,
            // File names
                // foo.rs
                0x66, 0x6f, 0x6f, 0x2e, 0x72, 0x73, 0x00,
                0x00,
                0x00,
                0x00,
                // bar.h
                0x62, 0x61, 0x72, 0x2e, 0x68, 0x00,
                0x01,
                0x00,
                0x00,
            // End file names.
            0x00,

            // Dummy line program data.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,

            // Dummy next line program.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
        ];

        let input = &mut EndianSlice::new(&buf, LittleEndian);

        match LineProgramHeader::parse(input, DebugLineOffset(0), 4, None, None) {
            Err(Error::UnexpectedEof(_)) => return,
            otherwise => panic!("Unexpected result: {:?}", otherwise),
        }
    }

    #[test]
    fn test_parse_debug_line_unit_length_too_short() {
        #[rustfmt::skip]
        let buf = [
            // 32-bit length = 40. TOO SHORT!!!
            0x28, 0x00, 0x00, 0x00,
            // Version.
            0x04, 0x00,
            // Header length = 40.
            0x28, 0x00, 0x00, 0x00,
            // Minimum instruction length.
            0x01,
            // Maximum operations per byte.
            0x01,
            // Default is_stmt.
            0x01,
            // Line base.
            0x00,
            // Line range.
            0x01,
            // Opcode base.
            0x03,
            // Standard opcode lengths for opcodes 1 .. opcode base - 1.
            0x01, 0x02,
            // Include directories = '/', 'i', 'n', 'c', '\0', '/', 'i', 'n', 'c', '2', '\0', '\0'
            0x2f, 0x69, 0x6e, 0x63, 0x00, 0x2f, 0x69, 0x6e, 0x63, 0x32, 0x00, 0x00,
            // File names
                // foo.rs
                0x66, 0x6f, 0x6f, 0x2e, 0x72, 0x73, 0x00,
                0x00,
                0x00,
                0x00,
                // bar.h
                0x62, 0x61, 0x72, 0x2e, 0x68, 0x00,
                0x01,
                0x00,
                0x00,
            // End file names.
            0x00,

            // Dummy line program data.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,

            // Dummy next line program.
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00,
        ];

        let input = &mut EndianSlice::new(&buf, LittleEndian);

        match LineProgramHeader::parse(input, DebugLineOffset(0), 4, None, None) {
            Err(Error::UnexpectedEof(_)) => return,
            otherwise => panic!("Unexpected result: {:?}", otherwise),
        }
    }

    const OPCODE_BASE: u8 = 13;
    const STANDARD_OPCODE_LENGTHS: &[u8] = &[0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1];

    fn make_test_header(
        buf: EndianSlice<LittleEndian>,
    ) -> LineProgramHeader<EndianSlice<LittleEndian>> {
        let encoding = Encoding {
            format: Format::Dwarf32,
            version: 4,
            address_size: 8,
        };
        let line_encoding = LineEncoding {
            line_base: -3,
            line_range: 12,
            ..Default::default()
        };
        LineProgramHeader {
            encoding,
            offset: DebugLineOffset(0),
            unit_length: 1,
            header_length: 1,
            line_encoding,
            opcode_base: OPCODE_BASE,
            standard_opcode_lengths: EndianSlice::new(STANDARD_OPCODE_LENGTHS, LittleEndian),
            file_names: vec![
                FileEntry {
                    path_name: AttributeValue::String(EndianSlice::new(b"foo.c", LittleEndian)),
                    directory_index: 0,
                    timestamp: 0,
                    size: 0,
                    md5: [0; 16],
                },
                FileEntry {
                    path_name: AttributeValue::String(EndianSlice::new(b"bar.rs", LittleEndian)),
                    directory_index: 0,
                    timestamp: 0,
                    size: 0,
                    md5: [0; 16],
                },
            ],
            include_directories: vec![],
            directory_entry_format: vec![],
            file_name_entry_format: vec![],
            program_buf: buf,
            comp_dir: None,
            comp_file: None,
        }
    }

    fn make_test_program(
        buf: EndianSlice<LittleEndian>,
    ) -> IncompleteLineProgram<EndianSlice<LittleEndian>> {
        IncompleteLineProgram {
            header: make_test_header(buf),
        }
    }

    #[test]
    fn test_parse_special_opcodes() {
        for i in OPCODE_BASE..u8::MAX {
            let input = [i, 0, 0, 0];
            let input = EndianSlice::new(&input, LittleEndian);
            let header = make_test_header(input);

            let mut rest = input;
            let opcode =
                LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

            assert_eq!(*rest, *input.range_from(1..));
            assert_eq!(opcode, LineInstruction::Special(i));
        }
    }

    #[test]
    fn test_parse_standard_opcodes() {
        fn test<Operands>(
            raw: constants::DwLns,
            operands: Operands,
            expected: LineInstruction<EndianSlice<LittleEndian>>,
        ) where
            Operands: AsRef<[u8]>,
        {
            let mut input = Vec::new();
            input.push(raw.0);
            input.extend_from_slice(operands.as_ref());

            let expected_rest = [0, 1, 2, 3, 4];
            input.extend_from_slice(&expected_rest);

            let input = EndianSlice::new(&*input, LittleEndian);
            let header = make_test_header(input);

            let mut rest = input;
            let opcode =
                LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

            assert_eq!(opcode, expected);
            assert_eq!(*rest, expected_rest);
        }

        test(constants::DW_LNS_copy, [], LineInstruction::Copy);
        test(
            constants::DW_LNS_advance_pc,
            [42],
            LineInstruction::AdvancePc(42),
        );
        test(
            constants::DW_LNS_advance_line,
            [9],
            LineInstruction::AdvanceLine(9),
        );
        test(constants::DW_LNS_set_file, [7], LineInstruction::SetFile(7));
        test(
            constants::DW_LNS_set_column,
            [1],
            LineInstruction::SetColumn(1),
        );
        test(
            constants::DW_LNS_negate_stmt,
            [],
            LineInstruction::NegateStatement,
        );
        test(
            constants::DW_LNS_set_basic_block,
            [],
            LineInstruction::SetBasicBlock,
        );
        test(
            constants::DW_LNS_const_add_pc,
            [],
            LineInstruction::ConstAddPc,
        );
        test(
            constants::DW_LNS_fixed_advance_pc,
            [42, 0],
            LineInstruction::FixedAddPc(42),
        );
        test(
            constants::DW_LNS_set_prologue_end,
            [],
            LineInstruction::SetPrologueEnd,
        );
        test(
            constants::DW_LNS_set_isa,
            [57 + 0x80, 100],
            LineInstruction::SetIsa(12857),
        );
    }

    #[test]
    fn test_parse_unknown_standard_opcode_no_args() {
        let input = [OPCODE_BASE, 1, 2, 3];
        let input = EndianSlice::new(&input, LittleEndian);
        let mut standard_opcode_lengths = Vec::new();
        let mut header = make_test_header(input);
        standard_opcode_lengths.extend(header.standard_opcode_lengths.slice());
        standard_opcode_lengths.push(0);
        header.opcode_base += 1;
        header.standard_opcode_lengths = EndianSlice::new(&standard_opcode_lengths, LittleEndian);

        let mut rest = input;
        let opcode =
            LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

        assert_eq!(
            opcode,
            LineInstruction::UnknownStandard0(constants::DwLns(OPCODE_BASE))
        );
        assert_eq!(*rest, *input.range_from(1..));
    }

    #[test]
    fn test_parse_unknown_standard_opcode_one_arg() {
        let input = [OPCODE_BASE, 1, 2, 3];
        let input = EndianSlice::new(&input, LittleEndian);
        let mut standard_opcode_lengths = Vec::new();
        let mut header = make_test_header(input);
        standard_opcode_lengths.extend(header.standard_opcode_lengths.slice());
        standard_opcode_lengths.push(1);
        header.opcode_base += 1;
        header.standard_opcode_lengths = EndianSlice::new(&standard_opcode_lengths, LittleEndian);

        let mut rest = input;
        let opcode =
            LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

        assert_eq!(
            opcode,
            LineInstruction::UnknownStandard1(constants::DwLns(OPCODE_BASE), 1)
        );
        assert_eq!(*rest, *input.range_from(2..));
    }

    #[test]
    fn test_parse_unknown_standard_opcode_many_args() {
        let input = [OPCODE_BASE, 1, 2, 3];
        let input = EndianSlice::new(&input, LittleEndian);
        let args = EndianSlice::new(&input[1..], LittleEndian);
        let mut standard_opcode_lengths = Vec::new();
        let mut header = make_test_header(input);
        standard_opcode_lengths.extend(header.standard_opcode_lengths.slice());
        standard_opcode_lengths.push(3);
        header.opcode_base += 1;
        header.standard_opcode_lengths = EndianSlice::new(&standard_opcode_lengths, LittleEndian);

        let mut rest = input;
        let opcode =
            LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

        assert_eq!(
            opcode,
            LineInstruction::UnknownStandardN(constants::DwLns(OPCODE_BASE), args)
        );
        assert_eq!(*rest, []);
    }

    #[test]
    fn test_parse_extended_opcodes() {
        fn test<Operands>(
            raw: constants::DwLne,
            operands: Operands,
            expected: LineInstruction<EndianSlice<LittleEndian>>,
        ) where
            Operands: AsRef<[u8]>,
        {
            let mut input = Vec::new();
            input.push(0);

            let operands = operands.as_ref();
            input.push(1 + operands.len() as u8);

            input.push(raw.0);
            input.extend_from_slice(operands);

            let expected_rest = [0, 1, 2, 3, 4];
            input.extend_from_slice(&expected_rest);

            let input = EndianSlice::new(&input, LittleEndian);
            let header = make_test_header(input);

            let mut rest = input;
            let opcode =
                LineInstruction::parse(&header, &mut rest).expect("Should parse the opcode OK");

            assert_eq!(opcode, expected);
            assert_eq!(*rest, expected_rest);
        }

        test(
            constants::DW_LNE_end_sequence,
            [],
            LineInstruction::EndSequence,
        );
        test(
            constants::DW_LNE_set_address,
            [1, 2, 3, 4, 5, 6, 7, 8],
            LineInstruction::SetAddress(578_437_695_752_307_201),
        );
        test(
            constants::DW_LNE_set_discriminator,
            [42],
            LineInstruction::SetDiscriminator(42),
        );

        let mut file = Vec::new();
        // "foo.c"
        let path_name = [b'f', b'o', b'o', b'.', b'c', 0];
        file.extend_from_slice(&path_name);
        // Directory index.
        file.push(0);
        // Last modification of file.
        file.push(1);
        // Size of file.
        file.push(2);

        test(
            constants::DW_LNE_define_file,
            file,
            LineInstruction::DefineFile(FileEntry {
                path_name: AttributeValue::String(EndianSlice::new(b"foo.c", LittleEndian)),
                directory_index: 0,
                timestamp: 1,
                size: 2,
                md5: [0; 16],
            }),
        );

        // Unknown extended opcode.
        let operands = [1, 2, 3, 4, 5, 6];
        let opcode = constants::DwLne(99);
        test(
            opcode,
            operands,
            LineInstruction::UnknownExtended(opcode, EndianSlice::new(&operands, LittleEndian)),
        );
    }

    #[test]
    fn test_file_entry_directory() {
        let path_name = [b'f', b'o', b'o', b'.', b'r', b's', 0];

        let mut file = FileEntry {
            path_name: AttributeValue::String(EndianSlice::new(&path_name, LittleEndian)),
            directory_index: 1,
            timestamp: 0,
            size: 0,
            md5: [0; 16],
        };

        let mut header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let dir = AttributeValue::String(EndianSlice::new(b"dir", LittleEndian));
        header.include_directories.push(dir);

        assert_eq!(file.directory(&header), Some(dir));

        // Now test the compilation's current directory.
        file.directory_index = 0;
        assert_eq!(file.directory(&header), None);
    }

    fn assert_exec_opcode<'input>(
        header: LineProgramHeader<EndianSlice<'input, LittleEndian>>,
        mut registers: LineRow,
        opcode: LineInstruction<EndianSlice<'input, LittleEndian>>,
        expected_registers: LineRow,
        expect_new_row: bool,
    ) {
        let mut program = IncompleteLineProgram { header };
        let is_new_row = registers.execute(opcode, &mut program);

        assert_eq!(is_new_row, expect_new_row);
        assert_eq!(registers, expected_registers);
    }

    #[test]
    fn test_exec_special_noop() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::Special(16);
        let expected_registers = initial_registers;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_negative_line_advance() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.line.0 = 10;

        let opcode = LineInstruction::Special(13);

        let mut expected_registers = initial_registers;
        expected_registers.line.0 -= 3;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_positive_line_advance() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let initial_registers = LineRow::new(&header);

        let opcode = LineInstruction::Special(19);

        let mut expected_registers = initial_registers;
        expected_registers.line.0 += 3;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_positive_address_advance() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let initial_registers = LineRow::new(&header);

        let opcode = LineInstruction::Special(52);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 3;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_positive_address_and_line_advance() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let initial_registers = LineRow::new(&header);

        let opcode = LineInstruction::Special(55);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 3;
        expected_registers.line.0 += 3;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_positive_address_and_negative_line_advance() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.line.0 = 10;

        let opcode = LineInstruction::Special(49);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 3;
        expected_registers.line.0 -= 3;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_special_line_underflow() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.line.0 = 2;

        // -3 line advance.
        let opcode = LineInstruction::Special(13);

        let mut expected_registers = initial_registers;
        // Clamp at 0. No idea if this is the best way to handle this situation
        // or not...
        expected_registers.line.0 = 0;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_copy() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.address.0 = 1337;
        initial_registers.line.0 = 42;

        let opcode = LineInstruction::Copy;

        let expected_registers = initial_registers;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_advance_pc() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::AdvancePc(42);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 42;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_advance_pc_overflow() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let opcode = LineInstruction::AdvancePc(42);

        let mut initial_registers = LineRow::new(&header);
        initial_registers.address.0 = u64::MAX;

        let mut expected_registers = initial_registers;
        expected_registers.address.0 = 41;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_advance_line() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::AdvanceLine(42);

        let mut expected_registers = initial_registers;
        expected_registers.line.0 += 42;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_advance_line_overflow() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let opcode = LineInstruction::AdvanceLine(42);

        let mut initial_registers = LineRow::new(&header);
        initial_registers.line.0 = u64::MAX;

        let mut expected_registers = initial_registers;
        expected_registers.line.0 = 41;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_set_file_in_bounds() {
        for file_idx in 1..3 {
            let header = make_test_header(EndianSlice::new(&[], LittleEndian));
            let initial_registers = LineRow::new(&header);
            let opcode = LineInstruction::SetFile(file_idx);

            let mut expected_registers = initial_registers;
            expected_registers.file = file_idx;

            assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
        }
    }

    #[test]
    fn test_exec_set_file_out_of_bounds() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::SetFile(100);

        // The spec doesn't say anything about rejecting input programs
        // that set the file register out of bounds of the actual number
        // of files that have been defined. Instead, we cross our
        // fingers and hope that one gets defined before
        // `LineRow::file` gets called and handle the error at
        // that time if need be.
        let mut expected_registers = initial_registers;
        expected_registers.file = 100;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_file_entry_file_index_out_of_bounds() {
        // These indices are 1-based, so 0 is invalid. 100 is way more than the
        // number of files defined in the header.
        let out_of_bounds_indices = [0, 100];

        for file_idx in &out_of_bounds_indices[..] {
            let header = make_test_header(EndianSlice::new(&[], LittleEndian));
            let mut row = LineRow::new(&header);

            row.file = *file_idx;

            assert_eq!(row.file(&header), None);
        }
    }

    #[test]
    fn test_file_entry_file_index_in_bounds() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let mut row = LineRow::new(&header);

        row.file = 2;

        assert_eq!(row.file(&header), Some(&header.file_names()[1]));
    }

    #[test]
    fn test_exec_set_column() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::SetColumn(42);

        let mut expected_registers = initial_registers;
        expected_registers.column = 42;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_negate_statement() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::NegateStatement;

        let mut expected_registers = initial_registers;
        expected_registers.is_stmt = !initial_registers.is_stmt;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_set_basic_block() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.basic_block = false;

        let opcode = LineInstruction::SetBasicBlock;

        let mut expected_registers = initial_registers;
        expected_registers.basic_block = true;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_const_add_pc() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::ConstAddPc;

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 20;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_fixed_add_pc() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.op_index.0 = 1;

        let opcode = LineInstruction::FixedAddPc(10);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 += 10;
        expected_registers.op_index.0 = 0;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_set_prologue_end() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));

        let mut initial_registers = LineRow::new(&header);
        initial_registers.prologue_end = false;

        let opcode = LineInstruction::SetPrologueEnd;

        let mut expected_registers = initial_registers;
        expected_registers.prologue_end = true;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_set_isa() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::SetIsa(1993);

        let mut expected_registers = initial_registers;
        expected_registers.isa = 1993;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_unknown_standard_0() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::UnknownStandard0(constants::DwLns(111));
        let expected_registers = initial_registers;
        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_unknown_standard_1() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::UnknownStandard1(constants::DwLns(111), 2);
        let expected_registers = initial_registers;
        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_unknown_standard_n() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::UnknownStandardN(
            constants::DwLns(111),
            EndianSlice::new(&[2, 2, 2], LittleEndian),
        );
        let expected_registers = initial_registers;
        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_end_sequence() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::EndSequence;

        let mut expected_registers = initial_registers;
        expected_registers.end_sequence = true;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, true);
    }

    #[test]
    fn test_exec_set_address() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::SetAddress(3030);

        let mut expected_registers = initial_registers;
        expected_registers.address.0 = 3030;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_define_file() {
        let mut program = make_test_program(EndianSlice::new(&[], LittleEndian));
        let mut row = LineRow::new(program.header());

        let file = FileEntry {
            path_name: AttributeValue::String(EndianSlice::new(b"test.cpp", LittleEndian)),
            directory_index: 0,
            timestamp: 0,
            size: 0,
            md5: [0; 16],
        };

        let opcode = LineInstruction::DefineFile(file);
        let is_new_row = row.execute(opcode, &mut program);

        assert_eq!(is_new_row, false);
        assert_eq!(Some(&file), program.header().file_names.last());
    }

    #[test]
    fn test_exec_set_discriminator() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::SetDiscriminator(9);

        let mut expected_registers = initial_registers;
        expected_registers.discriminator = 9;

        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    #[test]
    fn test_exec_unknown_extended() {
        let header = make_test_header(EndianSlice::new(&[], LittleEndian));
        let initial_registers = LineRow::new(&header);
        let opcode = LineInstruction::UnknownExtended(
            constants::DwLne(74),
            EndianSlice::new(&[], LittleEndian),
        );
        let expected_registers = initial_registers;
        assert_exec_opcode(header, initial_registers, opcode, expected_registers, false);
    }

    /// Ensure that `LineRows<R,P>` is covariant wrt R.
    /// This only needs to compile.
    #[allow(dead_code, unreachable_code, unused_variables)]
    fn test_line_rows_variance<'a, 'b>(_: &'a [u8], _: &'b [u8])
    where
        'a: 'b,
    {
        let a: &OneShotLineRows<EndianSlice<'a, LittleEndian>> = unimplemented!();
        let _: &OneShotLineRows<EndianSlice<'b, LittleEndian>> = a;
    }

    #[test]
    fn test_parse_debug_line_v5_ok() {
        let expected_lengths = &[1, 2];
        let expected_program = &[0, 1, 2, 3, 4];
        let expected_rest = &[5, 6, 7, 8, 9];
        let expected_include_directories = [
            AttributeValue::String(EndianSlice::new(b"dir1", LittleEndian)),
            AttributeValue::String(EndianSlice::new(b"dir2", LittleEndian)),
        ];
        let expected_file_names = [
            FileEntry {
                path_name: AttributeValue::String(EndianSlice::new(b"file1", LittleEndian)),
                directory_index: 0,
                timestamp: 0,
                size: 0,
                md5: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
            },
            FileEntry {
                path_name: AttributeValue::String(EndianSlice::new(b"file2", LittleEndian)),
                directory_index: 1,
                timestamp: 0,
                size: 0,
                md5: [
                    11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
                ],
            },
        ];

        for format in vec![Format::Dwarf32, Format::Dwarf64] {
            let length = Label::new();
            let header_length = Label::new();
            let start = Label::new();
            let header_start = Label::new();
            let end = Label::new();
            let header_end = Label::new();
            let section = Section::with_endian(Endian::Little)
                .initial_length(format, &length, &start)
                .D16(5)
                // Address size.
                .D8(4)
                // Segment selector size.
                .D8(0)
                .word_label(format.word_size(), &header_length)
                .mark(&header_start)
                // Minimum instruction length.
                .D8(1)
                // Maximum operations per byte.
                .D8(1)
                // Default is_stmt.
                .D8(1)
                // Line base.
                .D8(0)
                // Line range.
                .D8(1)
                // Opcode base.
                .D8(expected_lengths.len() as u8 + 1)
                // Standard opcode lengths for opcodes 1 .. opcode base - 1.
                .append_bytes(expected_lengths)
                // Directory entry format count.
                .D8(1)
                .uleb(constants::DW_LNCT_path.0 as u64)
                .uleb(constants::DW_FORM_string.0 as u64)
                // Directory count.
                .D8(2)
                .append_bytes(b"dir1\0")
                .append_bytes(b"dir2\0")
                // File entry format count.
                .D8(3)
                .uleb(constants::DW_LNCT_path.0 as u64)
                .uleb(constants::DW_FORM_string.0 as u64)
                .uleb(constants::DW_LNCT_directory_index.0 as u64)
                .uleb(constants::DW_FORM_data1.0 as u64)
                .uleb(constants::DW_LNCT_MD5.0 as u64)
                .uleb(constants::DW_FORM_data16.0 as u64)
                // File count.
                .D8(2)
                .append_bytes(b"file1\0")
                .D8(0)
                .append_bytes(&expected_file_names[0].md5)
                .append_bytes(b"file2\0")
                .D8(1)
                .append_bytes(&expected_file_names[1].md5)
                .mark(&header_end)
                // Dummy line program data.
                .append_bytes(expected_program)
                .mark(&end)
                // Dummy trailing data.
                .append_bytes(expected_rest);
            length.set_const((&end - &start) as u64);
            header_length.set_const((&header_end - &header_start) as u64);
            let section = section.get_contents().unwrap();

            let input = &mut EndianSlice::new(&section, LittleEndian);

            let header = LineProgramHeader::parse(input, DebugLineOffset(0), 0, None, None)
                .expect("should parse header ok");

            assert_eq!(header.raw_program_buf().slice(), expected_program);
            assert_eq!(input.slice(), expected_rest);

            assert_eq!(header.offset, DebugLineOffset(0));
            assert_eq!(header.version(), 5);
            assert_eq!(header.address_size(), 4);
            assert_eq!(header.minimum_instruction_length(), 1);
            assert_eq!(header.maximum_operations_per_instruction(), 1);
            assert_eq!(header.default_is_stmt(), true);
            assert_eq!(header.line_base(), 0);
            assert_eq!(header.line_range(), 1);
            assert_eq!(header.opcode_base(), expected_lengths.len() as u8 + 1);
            assert_eq!(header.standard_opcode_lengths().slice(), expected_lengths);
            assert_eq!(
                header.directory_entry_format(),
                &[FileEntryFormat {
                    content_type: constants::DW_LNCT_path,
                    form: constants::DW_FORM_string,
                }]
            );
            assert_eq!(header.include_directories(), expected_include_directories);
            assert_eq!(header.directory(0), Some(expected_include_directories[0]));
            assert_eq!(
                header.file_name_entry_format(),
                &[
                    FileEntryFormat {
                        content_type: constants::DW_LNCT_path,
                        form: constants::DW_FORM_string,
                    },
                    FileEntryFormat {
                        content_type: constants::DW_LNCT_directory_index,
                        form: constants::DW_FORM_data1,
                    },
                    FileEntryFormat {
                        content_type: constants::DW_LNCT_MD5,
                        form: constants::DW_FORM_data16,
                    }
                ]
            );
            assert_eq!(header.file_names(), expected_file_names);
            assert_eq!(header.file(0), Some(&expected_file_names[0]));
        }
    }
}