unofficial mirror of emacs-devel@gnu.org 
 help / color / mirror / code / Atom feed
blob a05b2c47ce1da2e61f05a954ec5e0a7b72e2cef7 161282 bytes (raw)
name: src/pdumper.c 	 # note: path name is non-authoritative(*)

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

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <math.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "blockinput.h"
#include "buffer.h"
#include "charset.h"
#include "coding.h"
#include "fingerprint.h"
#include "frame.h"
#include "getpagesize.h"
#include "intervals.h"
#include "lisp.h"
#include "pdumper.h"
#include "window.h"


/*
  TODO:

  - Make sure global finalizer list makes it across the dump.

  - Respect dump_object_contents.

  - Two-pass dumping: first assemble object list, then write all.

  - Don't emit relocations that happen to set Emacs memory locations
    to values they will already have.

  - Check at dump time that relocations are properly aligned.

  - Nullify frame_and_buffer_state.

  - Preferred base address for relocation-free non-PIC startup.

  - Compressed dump support.

  - Automate detection of struct layout changes.

*/


#ifdef HAVE_PDUMPER

#ifdef __GNUC__
# pragma GCC diagnostic error "-Wconversion"
# pragma GCC diagnostic error "-Wshadow"
# define ALLOW_IMPLICIT_CONVERSION                       \
  _Pragma ("GCC diagnostic push")                        \
  _Pragma ("GCC diagnostic ignored \"-Wconversion\"")
  _Pragma ("GCC diagnostic ignored \"-Wsign-conversion\"")
# define DISALLOW_IMPLICIT_CONVERSION \
  _Pragma ("GCC diagnostic pop")
#else
# define ALLOW_IMPLICIT_CONVERSION ((void)0)
# define DISALLOW_IMPLICIT_CONVERSION ((void)0)
#endif

#define VM_POSIX 1
#define VM_MS_WINDOWS 2

#if defined (HAVE_MMAP) && defined (MAP_FIXED)
# define VM_SUPPORTED VM_POSIX
# if !defined (MAP_POPULATE) && defined (MAP_PREFAULT_READ)
#  define MAP_POPULATE MAP_PREFAULT_READ
# elif !defined (MAP_POPULATE)
#  define MAP_POPULATE 0
# endif
#elif defined (WINDOWSNT)
  /* Use a float infinity, to avoid compiler warnings in comparing vs
     candidates' score.  */
# undef INFINITY
# define INFINITY __builtin_inff ()
# include <windows.h>
# define VM_SUPPORTED VM_MS_WINDOWS
#else
# define VM_SUPPORTED 0
#endif

#define DANGEROUS 0

/* PDUMPER_CHECK_REHASHING being true causes the portable dumper to
   check, for each hash table it dumps, that the hash table means the
   same thing after rehashing.  */
#ifndef PDUMPER_CHECK_REHASHING
# if ENABLE_CHECKING
#  define PDUMPER_CHECK_REHASHING 1
# else
#  define PDUMPER_CHECK_REHASHING 0
# endif
#endif

/* We require an architecture in which all pointers are the same size
   and have the same layout, where pointers are either 32 or 64 bits
   long, and where bytes have eight bits --- that is, a
   general-purpose computer made after 1990.  */
verify (sizeof (ptrdiff_t) == sizeof (void*));
verify (sizeof (intptr_t) == sizeof (ptrdiff_t));
verify (sizeof (void (*)(void)) == sizeof (void*));
verify (sizeof (ptrdiff_t) <= sizeof (Lisp_Object));
verify (sizeof (ptrdiff_t) <= sizeof (EMACS_INT));
verify (sizeof (off_t) == sizeof (int32_t) ||
        sizeof (off_t) == sizeof (int64_t));
verify (CHAR_BIT == 8);

#define DIVIDE_ROUND_UP(x, y) (((x) + (y) - 1) / (y))

static const char dump_magic[16] = {
  'D', 'U', 'M', 'P', 'E', 'D',
  'G', 'N', 'U',
  'E', 'M', 'A', 'C', 'S'
};

static pdumper_hook dump_hooks[24];
static int nr_dump_hooks = 0;

static struct
{
  void *mem;
  int sz;
} remembered_data[32];
static int nr_remembered_data = 0;

typedef int32_t dump_off;
#define DUMP_OFF_T_MIN INT32_MIN
#define DUMP_OFF_T_MAX INT32_MAX

__attribute__((format (printf,1,2)))
static void
dump_trace (const char *fmt, ...)
{
  if (0)
    {
      va_list args;
      va_start (args, fmt);
      vfprintf (stderr, fmt, args);
      va_end (args);
    }
}

static ssize_t dump_read_all (int fd, void *buf, size_t bytes_to_read);

static dump_off
ptrdiff_t_to_dump_off (ptrdiff_t value)
{
  eassert (DUMP_OFF_T_MIN <= value);
  eassert (value <= DUMP_OFF_T_MAX);
  return (dump_off) value;
}

/* Worst-case allocation granularity on any system that might load
   this dump.  */
static int
dump_get_page_size (void)
{
#ifdef WINDOWSNT
  return 64 * 1024;  /* Worst-case allocation granularity.  */
#else
  return getpagesize ();
#endif
}

#define dump_offsetof(type, member)                             \
  (ptrdiff_t_to_dump_off (offsetof (type, member)))

enum dump_reloc_type
  {
    /* dump_ptr = dump_ptr + emacs_basis() */
    RELOC_DUMP_TO_EMACS_PTR_RAW,
    /* dump_ptr = dump_ptr + dump_base */
    RELOC_DUMP_TO_DUMP_PTR_RAW,
    /* dump_lv = make_lisp_ptr (
         dump_lv + dump_base,
         type - RELOC_DUMP_TO_DUMP_LV)
       (Special case for symbols: make_lisp_symbol)
       Must be second-last.  */
    RELOC_DUMP_TO_DUMP_LV,
    /* dump_lv = make_lisp_ptr (
         dump_lv + emacs_basis(),
         type - RELOC_DUMP_TO_DUMP_LV)
       (Special case for symbols: make_lisp_symbol.)
       Must be last.  */
    RELOC_DUMP_TO_EMACS_LV = RELOC_DUMP_TO_DUMP_LV + 8,
  };

enum emacs_reloc_type
  {
    /* Copy raw bytes from the dump into Emacs.  */
    RELOC_EMACS_COPY_FROM_DUMP,
    /* Set a piece of memory in Emacs to a value we store directly in
       this relocation.  The length field contains the number of bytes
       we actually copy into Emacs.  */
    RELOC_EMACS_IMMEDIATE,
    /* Set an aligned pointer-sized object in Emacs to a dump offset.  */
    RELOC_EMACS_DUMP_PTR_RAW,
    /* Set an aligned pointer-sized object in Emacs to point to
       something also in Emacs.  */
    RELOC_EMACS_EMACS_PTR_RAW,
    /* Set an aligned Lisp_Object in Emacs to point to a value in the
       dump.  Must be last.  */
    RELOC_EMACS_DUMP_LV,
  };

#define EMACS_RELOC_TYPE_BITS 3
#define EMACS_RELOC_LENGTH_BITS                         \
  (sizeof (dump_off) * CHAR_BIT - EMACS_RELOC_TYPE_BITS)

struct emacs_reloc
{
  ENUM_BF (emacs_reloc_type) type : EMACS_RELOC_TYPE_BITS;
  dump_off length : EMACS_RELOC_LENGTH_BITS;
  dump_off emacs_offset;
  union
  {
    dump_off dump_offset;
    dump_off emacs_offset2;
    intmax_t immediate;
    int8_t immediate_i8;
    int16_t immediate_i16;
    int32_t immediate_i32;
  } u;
};

/* Set the type of an Emacs relocation.

   Also make sure that the type fits in the bitfield.  */
static void
emacs_reloc_set_type (struct emacs_reloc *reloc,
                      enum emacs_reloc_type type)
{
  reloc->type = type;
  eassert (reloc->type == type);
}

struct dump_table_locator
{
  /* Offset in dump, in bytes, of the first entry in the dump
     table.  */
  dump_off offset;
  /* Number of entries in the dump table.  We need an explicit end
     indicator (as opposed to a special sentinel) so we can efficiency
     binary search over the relocation entries.  */
  dump_off nr_entries;
};

#define DUMP_RELOC_TYPE_BITS 4
#define DUMP_RELOC_ALIGNMENT_BITS 2
#define DUMP_RELOC_OFFSET_BITS                          \
  (sizeof (dump_off) * CHAR_BIT - DUMP_RELOC_TYPE_BITS)

struct dump_reloc
{
  uint32_t raw_offset : DUMP_RELOC_OFFSET_BITS;
  ENUM_BF (dump_reloc_type) type : DUMP_RELOC_TYPE_BITS;
};

/* Set the type of a dump relocation.

   Also assert that the type fits in the bitfield.  */
static void
dump_reloc_set_type (struct dump_reloc *reloc, enum dump_reloc_type type)
{
  reloc->type = type;
  eassert (reloc->type == type);
}

static dump_off
dump_reloc_get_offset (struct dump_reloc reloc)
{
  return reloc.raw_offset << DUMP_RELOC_ALIGNMENT_BITS;
}

static void
dump_reloc_set_offset (struct dump_reloc *reloc, dump_off offset)
{
  eassert (offset >= 0);
  ALLOW_IMPLICIT_CONVERSION;
  reloc->raw_offset = offset >> DUMP_RELOC_ALIGNMENT_BITS;
  DISALLOW_IMPLICIT_CONVERSION;
  if (dump_reloc_get_offset (*reloc) != offset)
    error ("dump relocation out of range");
}

static void dump_fingerprint (const char* label, const uint8_t* xfingerprint) {
  fprintf (stderr, "%s: ", label);
  for (int i = 0; i <32; ++i) {
    fprintf (stderr, "%02x", (unsigned) xfingerprint[i]);
  }
  fprintf (stderr, "\n");
}

/* Format of an Emacs portable dump file.  All offsets are relative to
   the beginning of the file.  An Emacs portable dump file is coupled
   to exactly the Emacs binary that produced it, so details of
   alignment and endianness are unimportant.

   An Emacs dump file contains the contents of the Lisp heap.
   On startup, Emacs can start faster by mapping a dump file into
   memory and using the objects contained inside it instead of
   performing initialization from scratch.

   The dump file can be loaded at arbitrary locations in memory, so it
   includes a table of relocations that let Emacs adjust the pointers
   embedded in the dump file to account for the location where it was
   actually loaded.

   Dump files can contain pointers to other objects in the dump file
   or to parts of the Emacs binary.  */
struct dump_header
{
  /* File type magic.  */
  char magic[sizeof (dump_magic)];

  /* Associated Emacs binary.  */
  uint8_t fingerprint[32];

  /* Relocation table for the dump file; each entry is a
     struct dump_reloc.  */
  struct dump_table_locator dump_relocs;

  /* "Relocation" table we abuse to hold information about the
     location and type of each lisp object in the dump.  We need for
     pdumper_object_type and ultimately for conservative GC
     correctness.  */
  struct dump_table_locator object_starts;

  /* Relocation table for Emacs; each entry is a struct
     emacs_reloc.  */
  struct dump_table_locator emacs_relocs;

  /* Start of sub-region of hot region that we can discard after load
     completes.  The discardable region ends at cold_start.

     This region contains objects that we copy into the Emacs image at
     dump-load time.  */
  dump_off discardable_start;

  /* Start of the region that does not require relocations and that we
     expect never to be modified.  This region can be memory-mapped
     directly from the backing dump file with the reasonable
     expectation of taking few copy-on-write faults.

     For correctness, however, this region must be modifible, since in
     rare cases it is possible to see modifications to these bytes.
     For example, this region contains string data, and it's
     technically possible for someone to ASET a string character
     (although nobody tends to do that).

     The start of the cold region is always aligned on a page
     boundary.  */
  dump_off cold_start;
};

/* Double-ended singly linked list.  */
struct dump_tailq
{
  Lisp_Object head;
  Lisp_Object tail;
  intptr_t length;
};

/* Queue of objects to dump.  */
struct dump_queue
{
  /* Objects with no link weights at all.  Kept in dump order.  */
  struct dump_tailq zero_weight_objects;
  /* Objects with simple link weight: just one entry of type
     WEIGHT_NORMAL.  Score in this special case is non-decreasing as
     position increases, so we can avoid the need to rescan a big list
     for each object by storing these objects in order.  */
  struct dump_tailq one_weight_normal_objects;
  /* Likewise, for objects with one WEIGHT_STRONG weight.  */
  struct dump_tailq one_weight_strong_objects;
  /* List of objects with complex link weights --- i.e., not one of
     the above cases.  Order is irrelevant, since we scan the whole
     list every time.  Relatively few objects end up here.  */
  struct dump_tailq fancy_weight_objects;
  /* Hash table of link weights: maps an object to a list of zero or
     more (BASIS . WEIGHT) pairs.  As a special case, an object with
     zero weight is marked by Qt in the hash table --- this way, we
     can distinguish objects we've seen but that have no weight from
     ones that we haven't seen at all.  */
  Lisp_Object link_weights;
  /* Hash table mapping object to a sequence number --- used to
     resolve ties.  */
  Lisp_Object sequence_numbers;
  dump_off next_sequence_number;
};

enum cold_op
  {
    COLD_OP_OBJECT,
    COLD_OP_STRING,
    COLD_OP_CHARSET,
    COLD_OP_BUFFER,
  };

/* This structure controls what operations we perform inside
   dump_object.  */
struct dump_flags
{
  /* Actually write object contents to the dump.  Without this flag
     set, we still scan objects and enqueue pointed-to objects; making
     this flag false is useful when we want to process an object's
     referents normally, but dump an object itself separately,
     later.  */
  bool_bf dump_object_contents : 1;
  /* Record object starts. We turn this flag off when writing to the
     discardable section so that we don't trick conservative GC into
     thinking we have objects there.  Ignored (we never record object
     starts) if dump_object_contents is false.  */
  bool_bf dump_object_starts : 1;
  /* Pack objects tighter than GC memory alignment would normally
     require.  Useful for objects copied into the Emacs image instead
     of used directly from the loaded dump.

     XXX: actually use

     */
  bool_bf pack_objects : 1;
  /* Sometimes we dump objects that we've already scanned for outbound
     references to other objects.  These objects should not cause new
     objects to enter the object dumping queue.  This flag causes Emacs
     to assert that no new objects are enqueued while dumping.  */
  bool_bf assert_already_seen : 1;
  /* Punt on unstable hash tables: defer them to ctx->deferred_hash_tables.  */
  bool_bf defer_hash_tables : 1;
  /* Punt on symbols: defer them to ctx->deferred_symbols.  */
  bool_bf defer_symbols : 1;
};

/* Information we use while we dump.  Note that we're not the garbage
   collector and can operate under looser constraints: specifically,
   we allocate memory during the dumping process.  */
struct dump_context
{
  /* Header we'll write to the dump file when done.  */
  struct dump_header header;

  Lisp_Object old_purify_flag;
  Lisp_Object old_post_gc_hook;

#ifdef REL_ALLOC
  bool blocked_ralloc;
#endif

  /* File descriptor for dumpfile; < 0 if closed.  */
  int fd;
  /* Name of dump file --- used for error reporting.  */
  Lisp_Object dump_filename;
  /* Current offset in dump file.  */
  dump_off offset;

  /* Starting offset of current object.  */
  dump_off obj_offset;

  /* Flags currently in effect for dumping.  */
  struct dump_flags flags;

  dump_off end_heap;

  /* Hash mapping objects we've already dumped to their offsets.  */
  Lisp_Object objects_dumped;

  /* Hash mapping objects to where we got them.  Used for debugging.  */
  Lisp_Object referrers;
  Lisp_Object current_referrer;
  bool have_current_referrer;

  /* Queue of objects to dump.  */
  struct dump_queue dump_queue;

  /* Deferred object lists.  */
  Lisp_Object deferred_hash_tables;
  Lisp_Object deferred_symbols;

  /* Fixups in the dump file.  */
  Lisp_Object fixups;
  /* Hash table mapping symbols to their pre-copy-queue fwd or blv
     structures (which we dump immediately before the start of the
     discardable section). */
  Lisp_Object symbol_aux;
  /* Queue of copied objects for special treatment.  */
  Lisp_Object copied_queue;
  /* Queue of cold objects to dump.  */
  Lisp_Object cold_queue;

  /* Relocations in the dump.  */
  Lisp_Object dump_relocs;
  /* Object starts.  */
  Lisp_Object object_starts;
  /* Relocations in Emacs.  */
  Lisp_Object emacs_relocs;

  unsigned number_hot_relocations;
  unsigned number_discardable_relocations;
};

/* These special values for use as offsets in dump_remember_object and
   dump_recall_object indicate that the corresponding object isn't in
   the dump yet (and so it has no valid offset), but that it's on one
   of our to-be-dumped-later object queues (or that we haven't seen it
   at all).  All values must be greater than or equal to zero. */
enum dump_object_special_offset {
  DUMP_OBJECT_DEFERRED = -2,
  DUMP_OBJECT_ON_NORMAL_QUEUE = -1,
  DUMP_OBJECT_NOT_SEEN = 0,
};

/* Weights for score scores for object non-locality.  */
enum link_weight_enum
  {
    WEIGHT_NONE_VALUE = 0,
    WEIGHT_NORMAL_VALUE = 1000,
    WEIGHT_STRONG_VALUE = 1200,
  };

struct link_weight
{
  enum link_weight_enum value;
};

#define LINK_WEIGHT_LITERAL(x) ((struct link_weight){.value=(x)})
#define WEIGHT_NONE LINK_WEIGHT_LITERAL (WEIGHT_NONE_VALUE)
#define WEIGHT_NORMAL LINK_WEIGHT_LITERAL (WEIGHT_NORMAL_VALUE)
#define WEIGHT_STRONG LINK_WEIGHT_LITERAL (WEIGHT_STRONG_VALUE)

\f
/* Dump file creation */

static dump_off dump_object (struct dump_context *ctx, Lisp_Object object);
static dump_off dump_object_for_offset (
  struct dump_context *ctx, Lisp_Object object);

static void
dump_push (Lisp_Object *where, Lisp_Object newelt)
{
  *where = Fcons (newelt, *where);
}

static Lisp_Object
dump_pop (Lisp_Object *where)
{
  Lisp_Object ret = XCAR (*where);
  *where = XCDR (*where);
  return ret;
}

static bool
dump_tracking_referrers_p (struct dump_context *ctx)
{
  return !NILP (ctx->referrers);
}

static void
dump_set_have_current_referrer (struct dump_context *ctx, bool have)
{
#ifdef ENABLE_CHECKING
  ctx->have_current_referrer = have;
#endif
}

/* Remember the reason objects are enqueued.

   Until DUMP_CLEAR_REFERRER is called, any objects enqueued are being
   enqueued because OBJECT refers to them.  It is not legal to enqueue
   objects without a referer set.  We check this constraint
   at runtime.

   It is illegal to call DUMP_SET_REFERRER twice without an
   intervening call to DUMP_CLEAR_REFERRER.

   Define as a macro so we can avoid evaluating OBJECT
   if we dont want referrer tracking.  */
#define DUMP_SET_REFERRER(ctx, object)                   \
  do                                                     \
    {                                                    \
      struct dump_context *_ctx = (ctx);                 \
      eassert (!_ctx->have_current_referrer);            \
      dump_set_have_current_referrer (_ctx, true);       \
      if (dump_tracking_referrers_p (_ctx))              \
        ctx->current_referrer = (object);                \
    }                                                    \
  while (0)

/* Unset the referer that DUMP_SET_REFERRER set.

   Named with upper-case letters for symmetry with
   DUMP_SET_REFERRER.  */
static void
DUMP_CLEAR_REFERRER (struct dump_context *ctx)
{
  eassert (ctx->have_current_referrer);
  dump_set_have_current_referrer (ctx, false);
  if (dump_tracking_referrers_p (ctx))
    ctx->current_referrer = Qnil;
}

static Lisp_Object
dump_ptr_referrer (const char *label, void *address)
{
  char buf[128];
  buf[0] = '\0';
  sprintf (buf, "%s @ %p", label, address);
  return build_string (buf);
}

static void
print_paths_to_root (struct dump_context *ctx, Lisp_Object object);

static void dump_remember_cold_op (struct dump_context *ctx,
                                   enum cold_op op,
                                   Lisp_Object arg);

_Noreturn
static void
error_unsupported_dump_object (struct dump_context *ctx,
                               Lisp_Object object,
                               const char* msg)
{
  if (dump_tracking_referrers_p (ctx))
    print_paths_to_root (ctx, object);
  error ("unsupported object type in dump: %s", msg);
}

static uintptr_t
emacs_basis (void)
{
  return (uintptr_t) &Vpurify_flag;
}

static dump_off
emacs_offset (const void *emacs_ptr)
{
  /* TODO: assert that emacs_ptr is actually in emacs */
  eassert (emacs_ptr != NULL);
  intptr_t emacs_ptr_value = (intptr_t) emacs_ptr;
  ptrdiff_t emacs_ptr_relative = emacs_ptr_value - (intptr_t) emacs_basis ();
  return ptrdiff_t_to_dump_off (emacs_ptr_relative);
}

/* Return whether OBJECT is a symbol the storage of which is built
   into Emacs (and so is invariant across ASLR).  */
static bool
dump_builtin_symbol_p (Lisp_Object object)
{
  if (!SYMBOLP (object))
    return false;
  char* bp = (char*) lispsym;
  struct Lisp_Symbol *s = XSYMBOL (object);
  char* sp = (char*) s;
  return bp <= sp && sp < bp + sizeof (lispsym);
}

/* Return whether OBJECT has the same bit pattern in all Emacs
   invocations --- i.e., is invariant across a dump.  */
static bool
dump_object_self_representing_p (Lisp_Object object)
{
  bool result;
  ALLOW_IMPLICIT_CONVERSION;
  result =  INTEGERP (object) || dump_builtin_symbol_p (object);
  DISALLOW_IMPLICIT_CONVERSION;
  return result;
}

#define DEFINE_FROMLISP_FUNC(fn, type)          \
  static type                                   \
  fn (Lisp_Object value)                        \
  {                                             \
    type result;                                \
    ALLOW_IMPLICIT_CONVERSION;                  \
    CONS_TO_INTEGER (value, type, result);      \
    DISALLOW_IMPLICIT_CONVERSION;               \
    return result;                              \
  }

#define DEFINE_TOLISP_FUNC(fn, type) \
  static Lisp_Object                 \
  fn (type value)                    \
  {                                  \
    return INTEGER_TO_CONS (value);  \
  }

DEFINE_FROMLISP_FUNC (intmax_t_from_lisp, intmax_t);
DEFINE_TOLISP_FUNC (intmax_t_to_lisp, intmax_t);
DEFINE_FROMLISP_FUNC (dump_off_from_lisp, dump_off);
DEFINE_TOLISP_FUNC (dump_off_to_lisp, dump_off);

static void
dump_write (struct dump_context *ctx, const void *buf, dump_off nbyte)
{
  eassert (nbyte == 0 || buf != NULL);
  eassert (ctx->obj_offset == 0);
  eassert (ctx->flags.dump_object_contents);
  if (emacs_write (ctx->fd, buf, nbyte) < nbyte)
    report_file_error ("Could not write to dump file", ctx->dump_filename);
  ctx->offset += nbyte;
}

static Lisp_Object
make_eq_hash_table (void)
{
  return CALLN (Fmake_hash_table, QCtest, Qeq);
}

static void
dump_tailq_init (struct dump_tailq *tailq)
{
  tailq->head = tailq->tail = Qnil;
  tailq->length = 0;
}

static intptr_t
dump_tailq_length (const struct dump_tailq *tailq)
{
  return tailq->length;
}

__attribute__((unused))
static void
dump_tailq_prepend (struct dump_tailq *tailq, Lisp_Object value)
{
  Lisp_Object link = Fcons (value, tailq->head);
  tailq->head = link;
  if (NILP (tailq->tail))
    tailq->tail = link;
  tailq->length += 1;
}

__attribute__((unused))
static void
dump_tailq_append (struct dump_tailq *tailq, Lisp_Object value)
{
  Lisp_Object link = Fcons (value, Qnil);
  if (NILP (tailq->head))
    {
      eassert (NILP (tailq->tail));
      tailq->head = tailq->tail = link;
    }
  else
    {
      eassert (!NILP (tailq->tail));
      XSETCDR (tailq->tail, link);
      tailq->tail = link;
    }
  tailq->length += 1;
}

static bool
dump_tailq_empty_p (struct dump_tailq *tailq)
{
  return NILP (tailq->head);
}

static Lisp_Object
dump_tailq_peek (struct dump_tailq *tailq)
{
  eassert (!dump_tailq_empty_p (tailq));
  return XCAR (tailq->head);
}

static Lisp_Object
dump_tailq_pop (struct dump_tailq *tailq)
{
  eassert (!dump_tailq_empty_p (tailq));
  eassert (tailq->length > 0);
  tailq->length -= 1;
  Lisp_Object value = XCAR (tailq->head);
  tailq->head = XCDR (tailq->head);
  if (NILP (tailq->head))
    tailq->tail = Qnil;
  return value;
}

static void
dump_seek (struct dump_context *ctx, dump_off offset)
{
  eassert (ctx->obj_offset == 0);
  if (lseek (ctx->fd, offset, SEEK_SET) < 0)
    report_file_error ("Setting file position",
                       ctx->dump_filename);
  ctx->offset = offset;
}

static void
dump_write_zero (struct dump_context *ctx, dump_off nbytes)
{
  while (nbytes > 0)
    {
      uintmax_t zero = 0;
      dump_off to_write = sizeof (zero);
      if (to_write > nbytes)
        to_write = nbytes;
      dump_write (ctx, &zero, to_write);
      nbytes -= to_write;
    }
}

static void
dump_align_output (struct dump_context *ctx, int alignment)
{
  if (ctx->offset % alignment != 0)
    dump_write_zero (ctx, alignment - (ctx->offset % alignment));
}

static dump_off
dump_object_start (struct dump_context *ctx,
                   int alignment,
                   void *out,
                   dump_off outsz)
{
  /* We dump only one object at a time, so obj_offset should be
     invalid.  */
  eassert (ctx->obj_offset == 0);
  if (ctx->flags.pack_objects)
    alignment = 1;
  if (ctx->flags.dump_object_contents)
    dump_align_output (ctx, alignment);
  ctx->obj_offset = ctx->offset;
  memset (out, 0, outsz);
  return ctx->offset;
}

static dump_off
dump_object_finish (struct dump_context *ctx,
                    const void *out,
                    dump_off sz)
{
  dump_off offset = ctx->obj_offset;
  eassert (offset > 0);
  eassert (offset == ctx->offset); /* No intervening writes.  */
  ctx->obj_offset = 0;
  if (ctx->flags.dump_object_contents)
    dump_write (ctx, out, sz);
  return offset;
}

/* Return offset at which OBJECT has been dumped, or 0 if OBJECT has
   not been dumped.  */
static dump_off
dump_recall_object (struct dump_context *ctx, Lisp_Object object)
{
  Lisp_Object dumped = ctx->objects_dumped;
  return dump_off_from_lisp (Fgethash (object, dumped, make_number (0)));
}

static void
dump_remember_object (struct dump_context *ctx,
                      Lisp_Object object,
                      dump_off offset)
{
  Fputhash (object,
            dump_off_to_lisp (offset),
            ctx->objects_dumped);
}

static void
dump_note_reachable (struct dump_context *ctx, Lisp_Object object)
{
  eassert (ctx->have_current_referrer);
  if (!dump_tracking_referrers_p (ctx))
    return;
  Lisp_Object referrer = ctx->current_referrer;
  Lisp_Object obj_referrers = Fgethash (object, ctx->referrers, Qnil);
  if (NILP (Fmemq (referrer, obj_referrers)))
    Fputhash (object, Fcons (referrer, obj_referrers), ctx->referrers);
}

/* If this object lives in the Emacs image and not on the heap, return
   a pointer to the object data.  Otherwise, return NULL.  */
static void*
dump_object_emacs_ptr (Lisp_Object lv)
{
  if (SUBRP (lv))
    return XSUBR (lv);
  if (dump_builtin_symbol_p (lv))
    return XSYMBOL (lv);
  return NULL;
}

static void
dump_queue_init (struct dump_queue *dump_queue)
{
  dump_tailq_init (&dump_queue->zero_weight_objects);
  dump_tailq_init (&dump_queue->one_weight_normal_objects);
  dump_tailq_init (&dump_queue->one_weight_strong_objects);
  dump_tailq_init (&dump_queue->fancy_weight_objects);
  dump_queue->link_weights = make_eq_hash_table ();
  dump_queue->sequence_numbers = make_eq_hash_table ();
  dump_queue->next_sequence_number = 1;
}

static bool
dump_queue_empty_p (struct dump_queue *dump_queue)
{
  bool is_empty =
    EQ (Fhash_table_count (dump_queue->sequence_numbers),
        make_number (0));
  eassert (EQ (Fhash_table_count (dump_queue->sequence_numbers),
               Fhash_table_count (dump_queue->link_weights)));
  if (!is_empty)
    {
      eassert (
        !dump_tailq_empty_p (&dump_queue->zero_weight_objects) ||
        !dump_tailq_empty_p (&dump_queue->one_weight_normal_objects) ||
        !dump_tailq_empty_p (&dump_queue->one_weight_strong_objects) ||
        !dump_tailq_empty_p (&dump_queue->fancy_weight_objects));
    }
  else
    {
      /* If we're empty, we can still have a few stragglers on one of
         the above queues.  */
    }

  return is_empty;
}

static void
dump_queue_push_weight (Lisp_Object *weight_list,
                        dump_off basis,
                        struct link_weight weight)
{
  if (EQ (*weight_list, Qt))
    *weight_list = Qnil;
  dump_push (weight_list, Fcons (dump_off_to_lisp (basis),
                                 dump_off_to_lisp (weight.value)));
}

static void
dump_queue_enqueue (struct dump_queue *dump_queue,
                    Lisp_Object object,
                    dump_off basis,
                    struct link_weight weight)
{
  Lisp_Object weights = Fgethash (object, dump_queue->link_weights, Qnil);
  Lisp_Object orig_weights = weights;
  // N.B. want to find the last item of a given weight in each queue
  // due to prepend use.
  bool use_single_queues = true;
  if (NILP (weights))
    {
      /* Object is new.  */
      dump_trace ("new object %016x weight=%u\n",
                  (unsigned) XLI (object),
                  (unsigned) weight.value);

      if (weight.value == WEIGHT_NONE.value)
        {
          eassert (weight.value == 0);
          dump_tailq_prepend (&dump_queue->zero_weight_objects, object);
          weights = Qt;
        }
      else if (!use_single_queues)
        {
          dump_tailq_prepend (&dump_queue->fancy_weight_objects, object);
          dump_queue_push_weight (&weights, basis, weight);
        }
      else if (weight.value == WEIGHT_NORMAL.value)
        {
          dump_tailq_prepend (&dump_queue->one_weight_normal_objects, object);
          dump_queue_push_weight (&weights, basis, weight);
        }
      else if (weight.value == WEIGHT_STRONG.value)
        {
          dump_tailq_prepend (&dump_queue->one_weight_strong_objects, object);
          dump_queue_push_weight (&weights, basis, weight);
        }
      else
        {
          emacs_abort ();
        }

      Fputhash (object,
                dump_off_to_lisp(dump_queue->next_sequence_number++),
                dump_queue->sequence_numbers);
    }
  else
    {
      /* Object was already on the queue.  It's okay for an object to
         be on multiple queues so long as we maintain order
         invariants: attempting to dump an object multiple times is
         harmless, and most of the time, an object is only referenced
         once before being dumped, making this code path uncommon.  */
      if (weight.value != WEIGHT_NONE.value)
        {
          if (EQ (weights, Qt))
            {
              /* Object previously had a zero weight.  Once we
                 incorporate the link weight attached to this call,
                 the object will have a single weight.  Put the object
                 on the appropriate single-weight queue.  */
              weights = Qnil;
              if (!use_single_queues)
                dump_tailq_prepend (&dump_queue->fancy_weight_objects, object);
              else if (weight.value == WEIGHT_NORMAL.value)
                dump_tailq_prepend (
                  &dump_queue->one_weight_normal_objects, object);
              else if (weight.value == WEIGHT_STRONG.value)
                dump_tailq_prepend (
                  &dump_queue->one_weight_strong_objects, object);
              else
                emacs_abort ();
            }
          else if (use_single_queues && NILP (XCDR (weights)))
            dump_tailq_prepend (&dump_queue->fancy_weight_objects, object);
          dump_queue_push_weight (&weights, basis, weight);
        }
    }

  if (!EQ (weights, orig_weights))
    Fputhash (object, weights, dump_queue->link_weights);
}

static float
dump_calc_link_score (dump_off basis,
                      dump_off link_basis,
                      dump_off link_weight)
{
  float distance = (float)(basis - link_basis);
  eassert (distance >= 0);
  float link_score = powf (distance, -0.2f);
  return powf (link_score, (float) link_weight / 1000.0f);
}

/* Compute the score score for a queued object.

   OBJECT is the object to query, which must currently be queued for
   dumping.  BASIS is the offset at which we would be
   dumping the object; score is computed relative to BASIS and the
   various BASIS values supplied to dump_add_link_weight --- the
   further an object is from its referrers, the greater the
   score.  */
static float
dump_queue_compute_score (struct dump_queue *dump_queue,
                          Lisp_Object object,
                          dump_off basis)
{
  float score = 0;
  Lisp_Object object_link_weights =
    Fgethash (object, dump_queue->link_weights, Qnil);
  if (EQ (object_link_weights, Qt))
    object_link_weights = Qnil;
  while (!NILP (object_link_weights))
    {
      Lisp_Object basis_weight_pair = dump_pop (&object_link_weights);
      dump_off link_basis = dump_off_from_lisp (XCAR (basis_weight_pair));
      dump_off link_weight = dump_off_from_lisp (XCDR (basis_weight_pair));
      score += dump_calc_link_score (basis, link_basis, link_weight);
    }
  return score;
}

/* Scan the fancy part of the dump queue.

   BASIS is the position at which to evaluate the score function,
   usually ctx->offset.

   If we have at least one entry in the queue, return the pointer (in
   the singly-linked list) to the cons containing the object via
   *OUT_HIGHEST_SCORE_CONS_PTR and return its score.

   If the queue is empty, set *OUT_HIGHEST_SCORE_CONS_PTR to NULL
   and return negative infinity.  */
static float
dump_queue_scan_fancy (struct dump_queue *dump_queue,
                       dump_off basis,
                       Lisp_Object **out_highest_score_cons_ptr)
{
  Lisp_Object *cons_ptr = &dump_queue->fancy_weight_objects.head;
  Lisp_Object *highest_score_cons_ptr = NULL;
  float highest_score = -INFINITY;
  bool first = true;

  while (!NILP (*cons_ptr))
    {
      Lisp_Object queued_object = XCAR (*cons_ptr);
      float score = dump_queue_compute_score (
        dump_queue, queued_object, basis);
      if (first || score >= highest_score)
        {
          highest_score_cons_ptr = cons_ptr;
          highest_score = score;
          if (first)
            first = false;
        }
      cons_ptr = &XCONS (*cons_ptr)->u.s.u.cdr;
    }

  *out_highest_score_cons_ptr = highest_score_cons_ptr;
  return highest_score;
}

/* Return the sequence number of OBJECT.

   Return -1 if object doesn't have a sequence number.  This situation
   can occur when we've double-queued an object.  If this happens, we
   discard the errant object and try again.  */
static dump_off
dump_queue_sequence (struct dump_queue *dump_queue,
                     Lisp_Object object)
{
  Lisp_Object n = Fgethash (object, dump_queue->sequence_numbers, Qnil);
  return NILP (n) ? -1 : dump_off_from_lisp (n);
}

/* Find score and sequence at head of a one-weight object queue.

   Transparently discard stale objects from head of queue.  BASIS
   is the baseness for score computation.

   We organize these queues so that score is strictly decreasing, so
   examining the head is sufficient.  */
static void
dump_queue_find_score_of_one_weight_queue (
  struct dump_queue *dump_queue,
  dump_off basis,
  struct dump_tailq *one_weight_queue,
  float *out_score,
  int *out_sequence)
{
  /* Transparently discard stale objects from the head of this queue.  */
  do
    {
      if (dump_tailq_empty_p (one_weight_queue))
        {
          *out_score = -INFINITY;
          *out_sequence = 0;
        }
      else
        {
          Lisp_Object head = dump_tailq_peek (one_weight_queue);
          *out_sequence = dump_queue_sequence (dump_queue, head);
          if (*out_sequence < 0)
            dump_tailq_pop (one_weight_queue);
          else
            *out_score =
              dump_queue_compute_score (dump_queue, head, basis);
        }
    }
  while (*out_sequence < 0);
}

/* Pop the next object to dump from the dump queue.

   BASIS is the dump offset at which to evaluate score.

   The object returned is the queued object with the greatest score;
   by side effect, the object is removed from the dump queue.
   The dump queue must not be empty.  */
static Lisp_Object
dump_queue_dequeue (struct dump_queue *dump_queue, dump_off basis)
{
  eassert (EQ (Fhash_table_count (dump_queue->sequence_numbers),
               Fhash_table_count (dump_queue->link_weights)));

  eassert (
    XFASTINT (Fhash_table_count (dump_queue->sequence_numbers))
    <= (dump_tailq_length (&dump_queue->fancy_weight_objects) +
        dump_tailq_length (&dump_queue->zero_weight_objects) +
        dump_tailq_length (&dump_queue->one_weight_normal_objects) +
        dump_tailq_length (&dump_queue->one_weight_strong_objects)));

  bool dump_object_counts = true;
  if (dump_object_counts)
    dump_trace (
      "dump_queue_dequeue basis=%d fancy=%u zero=%u "
      "normal=%u strong=%u hash=%u\n",
      basis,
      (unsigned) dump_tailq_length (&dump_queue->fancy_weight_objects),
      (unsigned) dump_tailq_length (&dump_queue->zero_weight_objects),
      (unsigned) dump_tailq_length (&dump_queue->one_weight_normal_objects),
      (unsigned) dump_tailq_length (&dump_queue->one_weight_strong_objects),
      (unsigned) XFASTINT (Fhash_table_count (dump_queue->link_weights)));

  static const int nr_candidates = 3;
  struct candidate {
    float score;
    dump_off sequence;
  } candidates[nr_candidates];

  Lisp_Object *fancy_cons = NULL;
  candidates[0].sequence = 0;
  do
    {
      if (candidates[0].sequence < 0)
        *fancy_cons = XCDR (*fancy_cons);  /* Discard stale object.  */
      candidates[0].score = dump_queue_scan_fancy (
        dump_queue,
        basis,
        &fancy_cons);
      candidates[0].sequence =
        candidates[0].score > -INFINITY
        ? dump_queue_sequence (dump_queue, XCAR (*fancy_cons))
        : 0;
    }
  while (candidates[0].sequence < 0);

  dump_queue_find_score_of_one_weight_queue (
    dump_queue,
    basis,
    &dump_queue->one_weight_normal_objects,
    &candidates[1].score,
    &candidates[1].sequence);

  dump_queue_find_score_of_one_weight_queue (
    dump_queue,
    basis,
    &dump_queue->one_weight_strong_objects,
    &candidates[2].score,
    &candidates[2].sequence);

  int best = -1;
  for (int i = 0; i < nr_candidates; ++i)
    {
      eassert (candidates[i].sequence >= 0);
      if (candidates[i].score > -INFINITY &&
          (best < 0 ||
           candidates[i].score > candidates[best].score ||
           (candidates[i].score == candidates[best].score
            && candidates[i].sequence < candidates[best].sequence)))
        best = i;
    }

  Lisp_Object result;
  const char *src;
  if (best < 0)
    {
      src = "zero";
      result = dump_tailq_pop (&dump_queue->zero_weight_objects);
    }
  else if (best == 0)
    {
      src = "fancy";
      result = dump_tailq_pop (&dump_queue->fancy_weight_objects);
    }
  else if (best == 1)
    {
      src = "normal";
      result = dump_tailq_pop (&dump_queue->one_weight_normal_objects);
    }
  else if (best == 2)
    {
      src = "strong";
      result = dump_tailq_pop (&dump_queue->one_weight_strong_objects);
    }
  else
    emacs_abort ();

  dump_trace ("  result score=%f src=%s object=%016x\n",
              best < 0 ? -1.0 : (double) candidates[best].score,
              src,
              (unsigned) XLI (result));

  {
    Lisp_Object weights = Fgethash (result, dump_queue->link_weights, Qnil);
    while (!NILP (weights) && CONSP (weights))
      {
        Lisp_Object basis_weight_pair = dump_pop (&weights);
        dump_off link_basis =
          dump_off_from_lisp (XCAR (basis_weight_pair));
        dump_off link_weight =
          dump_off_from_lisp (XCDR (basis_weight_pair));
        dump_trace (
          "    link_basis=%d distance=%d weight=%d contrib=%f\n",
          link_basis,
          basis - link_basis,
          link_weight,
          (double) dump_calc_link_score (
            basis, link_basis, link_weight));
      }
  }

  Fremhash (result, dump_queue->link_weights);
  Fremhash (result, dump_queue->sequence_numbers);
  return result;
}

static void
dump_enqueue_object (struct dump_context *ctx,
                     Lisp_Object object,
                     struct link_weight weight)
{
  if (!dump_object_self_representing_p (object) ||
       dump_object_emacs_ptr (object))
    {
      dump_off state = dump_recall_object (ctx, object);
      bool already_dumped_object = state > DUMP_OBJECT_NOT_SEEN;
      if (ctx->flags.assert_already_seen)
        eassert (already_dumped_object);
      if (!already_dumped_object)
        {
          bool cold = BOOL_VECTOR_P (object) || FLOATP (object);
          if (state == DUMP_OBJECT_NOT_SEEN)
            {
              dump_remember_object (ctx, object, DUMP_OBJECT_ON_NORMAL_QUEUE);
              if (cold)
                dump_remember_cold_op (ctx, COLD_OP_OBJECT, object);
            }
          if (!cold &&
              state <= DUMP_OBJECT_NOT_SEEN &&
              state != DUMP_OBJECT_DEFERRED)
            dump_queue_enqueue (&ctx->dump_queue,
                                object,
                                ctx->offset,
                                weight);
        }
    }
  /* Always make sure that we have a referrer.  */
  dump_note_reachable (ctx, object);
}

static void
print_paths_to_root_1 (struct dump_context *ctx,
                       Lisp_Object object,
                       int level)
{
  Lisp_Object referrers = Fgethash (object, ctx->referrers, Qnil);
  while (!NILP (referrers))
    {
      Lisp_Object referrer = XCAR (referrers);
      referrers = XCDR (referrers);
      Lisp_Object repr = Fprin1_to_string (referrer, Qnil);
      for (int i = 0; i < level; ++i)
        fputc (' ', stderr);
      fprintf (stderr, "%s\n", SDATA (repr));
      print_paths_to_root_1 (ctx, referrer, level + 1);
    }
}

static void
print_paths_to_root (struct dump_context *ctx, Lisp_Object object)
{
  print_paths_to_root_1 (ctx, object, 0);
}

static void
dump_remember_cold_op (struct dump_context *ctx,
                       enum cold_op op,
                       Lisp_Object arg)
{
  if (ctx->flags.dump_object_contents)
    dump_push (&ctx->cold_queue, Fcons (make_number (op), arg));
}

/* Add a dump relocation that points into Emacs.

   Add a relocation that updates the pointer stored at DUMP_OFFSET to
   point into the Emacs binary upon dump load.  The pointer-sized
   value at DUMP_OFFSET in the dump file should contain a number
   relative to emacs_basis().  */
static void
dump_reloc_dump_to_emacs_ptr_raw (struct dump_context *ctx,
                                  dump_off dump_offset)
{
  if (ctx->flags.dump_object_contents)
    dump_push (&ctx->dump_relocs,
               list2 (dump_off_to_lisp (RELOC_DUMP_TO_EMACS_PTR_RAW),
                      dump_off_to_lisp (dump_offset)));
}

/* Add a dump relocation that points a Lisp_Object back at the dump.

   Add a relocation that updates the Lisp_Object at DUMP_OFFSET in the
   dump to point to another object in the dump.  The Lisp_Object-sized
   value at DUMP_OFFSET in the dump file should contain the offset of
   the target object relative to the start of the dump.  */
static void
dump_reloc_dump_to_dump_lv (struct dump_context *ctx,
                            dump_off dump_offset,
                            enum Lisp_Type type)
{
  if (!ctx->flags.dump_object_contents)
    return;

  int reloc_type;
  switch (type)
    {
    case Lisp_Symbol:
    case Lisp_Misc:
    case Lisp_String:
    case Lisp_Vectorlike:
    case Lisp_Cons:
    case Lisp_Float:
      reloc_type = RELOC_DUMP_TO_DUMP_LV + type;
      break;
    default:
      emacs_abort ();
    }

  dump_push (&ctx->dump_relocs,
             list2 (dump_off_to_lisp (reloc_type),
                    dump_off_to_lisp (dump_offset)));
}

/* Add a dump relocation that points a raw pointer back at the dump.

   Add a relocation that updates the raw pointer at DUMP_OFFSET in the
   dump to point to another object in the dump.  The pointer-sized
   value at DUMP_OFFSET in the dump file should contain the offset of
   the target object relative to the start of the dump.  */
static void
dump_reloc_dump_to_dump_ptr_raw (struct dump_context *ctx,
                                 dump_off dump_offset)
{
  if (ctx->flags.dump_object_contents)
    dump_push (&ctx->dump_relocs,
               list2 (dump_off_to_lisp (RELOC_DUMP_TO_DUMP_PTR_RAW),
                      dump_off_to_lisp (dump_offset)));
}

/* Add a dump relocation that points to a Lisp object in Emacs.

   Add a relocation that updates the Lisp_Object at DUMP_OFFSET in the
   dump to point to a lisp object in Emacs.  The Lisp_Object-sized
   value at DUMP_OFFSET in the dump file should contain the offset of
   the target object relative to emacs_basis().  TYPE is the type of
   Lisp value.  */
static void
dump_reloc_dump_to_emacs_lv (struct dump_context *ctx,
                             dump_off dump_offset,
                             enum Lisp_Type type)
{
  if (!ctx->flags.dump_object_contents)
    return;

  int reloc_type;
  switch (type)
    {
    case Lisp_Misc:
    case Lisp_String:
    case Lisp_Vectorlike:
    case Lisp_Cons:
    case Lisp_Float:
      reloc_type = RELOC_DUMP_TO_EMACS_LV + type;
      break;
    default:
      emacs_abort ();
    }

  dump_push (&ctx->dump_relocs,
             list2 (dump_off_to_lisp (reloc_type),
                    dump_off_to_lisp (dump_offset)));
}

/* Add an Emacs relocation that copies arbitrary bytes from the dump.

   When the dump is loaded, Emacs copies SIZE bytes from OFFSET in
   dump to LOCATION in the Emacs data section.  This copying happens
   after other relocations, so it's all right to, say, copy a
   Lisp_Object (since by the time we copy the Lisp_Object, it'll have
   been adjusted to account for the location of the running Emacs and
   dump file).  */
static void
dump_emacs_reloc_copy_from_dump (struct dump_context *ctx,
                                 dump_off dump_offset,
                                 void* emacs_ptr,
                                 dump_off size)
{
  eassert (size >= 0);
  eassert (size < (1 << EMACS_RELOC_LENGTH_BITS));

  if (!ctx->flags.dump_object_contents)
    return;

  if (size == 0)
    return;

  dump_push (&ctx->emacs_relocs,
             list4 (make_number (RELOC_EMACS_COPY_FROM_DUMP),
                    dump_off_to_lisp (emacs_offset (emacs_ptr)),
                    dump_off_to_lisp (dump_offset),
                    dump_off_to_lisp (size)));
}

/* Add an Emacs relocation that sets values to arbitrary bytes.

   When the dump is loaded, Emacs copies SIZE bytes from the
   relocation itself to the adjusted location inside Emacs EMACS_PTR.
   SIZE is the number of bytes to copy.  See struct emacs_reloc for
   the maximum size that this mechanism can support.  The value comes
   from VALUE_PTR.
 */
static void
dump_emacs_reloc_immediate (struct dump_context *ctx,
                            const void *emacs_ptr,
                            const void *value_ptr,
                            dump_off size)
{
  if (!ctx->flags.dump_object_contents)
    return;

  intmax_t value = 0;
  eassert (size <= sizeof (value));
  memcpy (&value, value_ptr, size);
  dump_push (&ctx->emacs_relocs,
             list4 (make_number (RELOC_EMACS_IMMEDIATE),
                    dump_off_to_lisp (emacs_offset (emacs_ptr)),
                    intmax_t_to_lisp (value),
                    dump_off_to_lisp (size)));
}

#define DEFINE_EMACS_IMMEDIATE_FN(fnname, type)                         \
  static void                                                           \
  fnname (struct dump_context *ctx,                                     \
          const type *emacs_ptr,                                        \
          type value)                                                   \
  {                                                                     \
    dump_emacs_reloc_immediate (                                        \
      ctx, emacs_ptr, &value, sizeof (value));                          \
  }

DEFINE_EMACS_IMMEDIATE_FN (dump_emacs_reloc_immediate_lv, Lisp_Object);
DEFINE_EMACS_IMMEDIATE_FN (dump_emacs_reloc_immediate_ptrdiff_t, ptrdiff_t);
DEFINE_EMACS_IMMEDIATE_FN (dump_emacs_reloc_immediate_emacs_int, EMACS_INT);
DEFINE_EMACS_IMMEDIATE_FN (dump_emacs_reloc_immediate_int, int);
DEFINE_EMACS_IMMEDIATE_FN (dump_emacs_reloc_immediate_bool, bool);

/* Add an emacs relocation that makes a raw pointer in Emacs point
   into the dump.  */
static void
dump_emacs_reloc_to_dump_ptr_raw (struct dump_context *ctx,
                                  const void* emacs_ptr,
                                  dump_off dump_offset)
{
  if (!ctx->flags.dump_object_contents)
    return;

  dump_push (&ctx->emacs_relocs,
             list3 (make_number (RELOC_EMACS_DUMP_PTR_RAW),
                    dump_off_to_lisp (emacs_offset (emacs_ptr)),
                    dump_off_to_lisp (dump_offset)));
}

/* Add an emacs relocation that points into the dump.

   When the dump is loaded, the Lisp_Object at EMACS_ROOT in Emacs to
   point to VALUE.  VALUE can be any Lisp value; this function
   automatically queues the value for dumping if necessary.  */
static void
dump_emacs_reloc_to_dump_lv (struct dump_context *ctx,
                             Lisp_Object *emacs_ptr,
                             Lisp_Object value)
{
  if (dump_object_self_representing_p (value))
    dump_emacs_reloc_immediate_lv (ctx, emacs_ptr, value);
  else
    {
      if (ctx->flags.dump_object_contents)
        dump_push (
          &ctx->emacs_relocs,
          list3 (dump_off_to_lisp (RELOC_EMACS_DUMP_LV + XTYPE (value)),
                 dump_off_to_lisp (emacs_offset (emacs_ptr)),
                 value));
      dump_enqueue_object (ctx, value, WEIGHT_NONE);
    }
}

/* Add an emacs relocation that makes a raw pointer in Emacs point
   back into the Emacs image.  */
static void
dump_emacs_reloc_to_emacs_ptr_raw (struct dump_context *ctx,
                                   void* emacs_ptr,
                                   void *target_emacs_ptr)
{
  if (!ctx->flags.dump_object_contents)
    return;

  dump_push (&ctx->emacs_relocs,
             list3 (make_number (RELOC_EMACS_EMACS_PTR_RAW),
                    dump_off_to_lisp (emacs_offset (emacs_ptr)),
                    dump_off_to_lisp (emacs_offset (target_emacs_ptr))));
}

/* Add an Emacs relocation that makes a raw pointer in Emacs point to
   a different part of Emacs.  */

enum dump_fixup_type
  {
    DUMP_FIXUP_LISP_OBJECT,
    DUMP_FIXUP_LISP_OBJECT_RAW,
    DUMP_FIXUP_PTR_DUMP_RAW,
  };

enum dump_lv_fixup_type
  {
    LV_FIXUP_LISP_OBJECT,
    LV_FIXUP_RAW_POINTER,
  };

/* Make something in the dump point to a lisp object.

   CTX is a dump context.  DUMP_OFFSET is the location in the dump to
   fix.  VALUE is the object to which the location in the dump
   should point.

   If FIXUP_SUBTYPE is LV_FIXUP_LISP_OBJECT, we expect a Lisp_Object
   at DUMP_OFFSET.  If it's LV_FIXUP_RAW_POINTER, we expect a pointer.
 */
static void
dump_remember_fixup_lv (struct dump_context *ctx,
                        dump_off dump_offset,
                        Lisp_Object value,
                        enum dump_lv_fixup_type fixup_subtype)
{
  if (!ctx->flags.dump_object_contents)
    return;

  dump_push (&ctx->fixups,
             list3 (
               make_number (fixup_subtype == LV_FIXUP_LISP_OBJECT
                            ? DUMP_FIXUP_LISP_OBJECT
                            : DUMP_FIXUP_LISP_OBJECT_RAW),
               dump_off_to_lisp (dump_offset),
               value));
}

/* Remember to fix up the dump file such that the pointer-sized value
   at DUMP_OFFSET points to NEW_DUMP_OFFSET in the dump file and to
   its absolute address at runtime.  */
static void
dump_remember_fixup_ptr_raw (struct dump_context *ctx,
                             dump_off dump_offset,
                             dump_off new_dump_offset)
{
  if (!ctx->flags.dump_object_contents)
    return;

  /* We should not be generating relocations into the
     to-be-copied-into-Emacs dump region.  */
  eassert (ctx->header.discardable_start == 0 ||
           new_dump_offset < ctx->header.discardable_start ||
           (ctx->header.cold_start != 0 &&
            new_dump_offset >= ctx->header.cold_start));

  dump_push (&ctx->fixups,
             list3 (
               make_number (DUMP_FIXUP_PTR_DUMP_RAW),
               dump_off_to_lisp (dump_offset),
               dump_off_to_lisp (new_dump_offset)));
}

static void
dump_root_visitor (Lisp_Object *root_ptr, enum gc_root_type type, void *data)
{
  struct dump_context *ctx = data;
  Lisp_Object value = *root_ptr;
  if (type == GC_ROOT_C_SYMBOL)
    {
      eassert (dump_builtin_symbol_p (value));
      /* Remember to dump the object itself later along with all the
         rest of the copied-to-Emacs objects.  */
      DUMP_SET_REFERRER (ctx, build_string ("built-in symbol list"));
      dump_enqueue_object (ctx, value, WEIGHT_NONE);
      DUMP_CLEAR_REFERRER (ctx);
    }
  else
    {
      if (root_ptr != &Vinternal_interpreter_environment)
        {
          DUMP_SET_REFERRER (ctx, dump_ptr_referrer ("emacs root", root_ptr));
          dump_emacs_reloc_to_dump_lv (ctx, root_ptr, *root_ptr);
          DUMP_CLEAR_REFERRER (ctx);
        }
    }
}

/* Kick off the dump process by queuing up the static GC roots.  */
static void
dump_roots (struct dump_context *ctx)
{
  struct gc_root_visitor visitor;
  memset (&visitor, 0, sizeof (visitor));
  visitor.visit = dump_root_visitor;
  visitor.data = ctx;
  visit_static_gc_roots (visitor);
}

static dump_off
field_relpos (const void *in_start, const void *in_field)
{
  ptrdiff_t in_start_val = (ptrdiff_t) in_start;
  ptrdiff_t in_field_val = (ptrdiff_t) in_field;
  eassert (in_start_val <= in_field_val);
  ptrdiff_t relpos = in_field_val - in_start_val;
  eassert (relpos < 1024); /* Sanity check.  */
  return (dump_off) relpos;
}

static void
cpyptr (void *out, const void *in)
{
  memcpy (out, in, sizeof (void *));
}

/* Convenience macro for regular assignment.  */
#define DUMP_FIELD_COPY(out, in, name) \
  do                                   \
    {                                  \
      (out)->name = (in)->name;        \
    }                                  \
  while (0)

static void
dump_field_lv_or_rawptr (struct dump_context *ctx,
                         void *out,
                         const void *in_start,
                         const void *in_field,
                         /* opt */ const enum Lisp_Type *ptr_raw_type,
                         struct link_weight weight)
{
  eassert (ctx->obj_offset > 0);

  Lisp_Object value;
  dump_off relpos = field_relpos (in_start, in_field);
  void *out_field = (char *) out + relpos;
  if (ptr_raw_type == NULL)
    {
      memcpy (&value, in_field, sizeof (value));
      if (dump_object_self_representing_p (value))
        {
          memcpy (out_field, &value, sizeof (value));
          return;
        }
    }
  else
    {
      void *ptrval;
      cpyptr (&ptrval, in_field);
      if (ptrval == NULL)
        return; /* Nothing to do.  */
      switch (*ptr_raw_type)
        {
        case Lisp_Symbol:
          value = make_lisp_symbol (ptrval);
          break;
        case Lisp_Misc:
        case Lisp_String:
        case Lisp_Vectorlike:
        case Lisp_Cons:
        case Lisp_Float:
          value = make_lisp_ptr (ptrval, *ptr_raw_type);
          break;
        default:
          emacs_abort ();
        }
    }

  bool is_ptr_raw = (ptr_raw_type != NULL);

  /* Now value is the Lisp_Object to which we want to point whether or
     not the field is a raw pointer (in which case we just synthesized
     the Lisp_Object outselves) or a Lisp_Object (in which case we
     just copied the thing).  Add a fixup or relocation.  */

  intptr_t out_value;
  dump_off out_field_offset = ctx->obj_offset + relpos;
  dump_off target_offset = dump_recall_object (ctx, value);
  if (DANGEROUS &&
      target_offset > 0 && dump_object_emacs_ptr (value) == NULL)
    {
      /* We've already dumped the referenced object, so we can emit
         the value and a relocation directly instead of indirecting
         through a fixup.  */
      out_value = target_offset;
      if (is_ptr_raw)
        dump_reloc_dump_to_dump_ptr_raw (ctx, out_field_offset);
      else
        dump_reloc_dump_to_dump_lv (ctx, out_field_offset, XTYPE (value));
    }
  else
    {
      /* We don't know about the target object yet, so add a fixup.
         When we process the fixup, we'll have dumped the target
         object.  */
      out_value = (intptr_t) 0xDEADF00D;
      dump_remember_fixup_lv (ctx,
                              out_field_offset,
                              value,
                              ( is_ptr_raw
                                ? LV_FIXUP_RAW_POINTER
                                : LV_FIXUP_LISP_OBJECT ));
      dump_enqueue_object (ctx, value, weight);
    }

  memcpy (out_field, &out_value, sizeof (out_value));
}

/* Set a pointer field on an output object during dump.

   CTX is the dump context.  OFFSET is the offset at which the current
   object starts.  OUT is a pointer to the dump output object.
   IN_START is the start of the current Emacs object.  IN_FIELD is a
   pointer to the field in that object.  TYPE is the type of pointer
   to which IN_FIELD points.
 */
static void
dump_field_lv_rawptr (struct dump_context *ctx,
                      void *out,
                      const void *in_start,
                      const void *in_field,
                      enum Lisp_Type type,
                      struct link_weight weight)
{
  dump_field_lv_or_rawptr (ctx, out, in_start, in_field, &type, weight);
}

/* Set a Lisp_Object field on an output object during dump.

   CTX is a dump context.  OFFSET is the offset at which the current
   object starts.  OUT is a pointer to the dump output object.
   IN_START is the start of the current Emacs object.  IN_FIELD is a
   pointer to a Lisp_Object field in that object.

   Arrange for the dump to contain fixups and relocations such that,
   at load time, the given field of the output object contains a valid
   Lisp_Object pointing to the same notional object that *IN_FIELD
   contains now.

   See idomatic usage below.  */
static void
dump_field_lv (struct dump_context *ctx,
               void *out,
               const void *in_start,
               const Lisp_Object *in_field,
               struct link_weight weight)
{
  dump_field_lv_or_rawptr (ctx, out, in_start, in_field, NULL, weight);
}

/* Note that we're going to add a manual fixup for the given field
   later.  */
static void
dump_field_fixup_later (struct dump_context *ctx,
                        void *out,
                        const void *in_start,
                        const void *in_field)
{
  // TODO: more error checking
  (void) field_relpos (in_start, in_field);
}

/* Mark an output object field, which is as wide as a poiner, as being
   fixed up to point to a specific offset in the dump.  */
static void
dump_field_ptr_to_dump_offset (struct dump_context *ctx,
                               void *out,
                               const void *in_start,
                               const void *in_field,
                               dump_off target_dump_offset)
{
  eassert (ctx->obj_offset > 0);
  if (!ctx->flags.dump_object_contents)
    return;

  dump_off relpos = field_relpos (in_start, in_field);
  dump_reloc_dump_to_dump_ptr_raw (ctx, ctx->obj_offset + relpos);
  intptr_t outval = target_dump_offset;
  memcpy ((char*) out + relpos, &outval, sizeof (outval));
}

/* Mark a field as pointing to a place inside Emacs.

   CTX is the dump context.  OUT points to the out-object for the
   current dump function.  IN_START points to the start of the object
   being dumped.  IN_FIELD points to the field inside the object being
   dumped that we're dumping.  The contents of this field (which
   should be as wide as a pointer) are the Emacs pointer to dump.

 */
static void
dump_field_emacs_ptr (struct dump_context *ctx,
                      void *out,
                      const void *in_start,
                      const void *in_field)
{
  eassert (ctx->obj_offset > 0);
  if (!ctx->flags.dump_object_contents)
    return;

  intptr_t abs_emacs_ptr;
  cpyptr (&abs_emacs_ptr, in_field);
  ptrdiff_t rel_emacs_ptr = abs_emacs_ptr - (intptr_t) emacs_basis ();
  dump_off relpos = field_relpos (in_start, in_field);
  cpyptr ((char*) out + relpos, &rel_emacs_ptr);
  dump_reloc_dump_to_emacs_ptr_raw (ctx, ctx->obj_offset + relpos);
}

static dump_off
dump_cons (struct dump_context *ctx, const struct Lisp_Cons *cons)
{
  struct Lisp_Cons out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  dump_field_lv (ctx, &out, cons, &cons->u.s.car, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, cons, &cons->u.s.u.cdr, WEIGHT_NORMAL);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_interval_tree (struct dump_context *ctx,
                    INTERVAL tree,
                    dump_off parent_offset)
{
  // TODO: output tree breadth-first?
  struct interval out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, tree, total_length);
  DUMP_FIELD_COPY (&out, tree, position);
  if (tree->left)
    dump_field_fixup_later (ctx, &out, tree, &tree->left);
  if (tree->right)
    dump_field_fixup_later (ctx, &out, tree, &tree->right);
  if (!tree->up_obj)
    {
      eassert (parent_offset != 0);
      dump_field_ptr_to_dump_offset (
        ctx, &out,
        tree, &tree->up.interval,
        parent_offset);
    }
  else
    dump_field_lv (ctx, &out, tree, &tree->up.obj, WEIGHT_STRONG);
  DUMP_FIELD_COPY (&out, tree, up_obj);
  eassert (tree->gcmarkbit == 0);
  DUMP_FIELD_COPY (&out, tree, write_protect);
  DUMP_FIELD_COPY (&out, tree, visible);
  DUMP_FIELD_COPY (&out, tree, front_sticky);
  DUMP_FIELD_COPY (&out, tree, rear_sticky);
  dump_field_lv (ctx, &out, tree, &tree->plist, WEIGHT_STRONG);
  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  if (tree->left)
      dump_remember_fixup_ptr_raw (
        ctx,
        offset + dump_offsetof (struct interval, left),
        dump_interval_tree (ctx, tree->left, offset));
  if (tree->right)
      dump_remember_fixup_ptr_raw (
        ctx,
        offset + dump_offsetof (struct interval, right),
        dump_interval_tree (ctx, tree->right, offset));
  return offset;
}

static dump_off
dump_string (struct dump_context *ctx, const struct Lisp_String *string)
{
  /* If we have text properties, write them _after_ the string so that
     at runtime, the prefetcher and cache will DTRT. (We access the
     string before its properties.).

     There's special code to dump string data contiguously later on.
     we seldom write to string data and never relocate it, so lumping
     it together at the end of the dump saves on COW faults.

     If, however, the string's size_byte field is -1, the string data
     is actually a pointer to Emacs data segment, so we can do even
     better by emitting a relocation instead of bothering to copy the
     string data.  */
  struct Lisp_String out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, string, u.s.size);
  DUMP_FIELD_COPY (&out, string, u.s.size_byte);
  if (string->u.s.intervals)
    dump_field_fixup_later (ctx, &out, string, &string->u.s.intervals);

  if (string->u.s.size_byte == -2)
    /* String literal in Emacs rodata.  */
    dump_field_emacs_ptr (ctx, &out, string, &string->u.s.data);
  else
    {
      dump_field_fixup_later (ctx, &out, string, &string->u.s.data);
      dump_remember_cold_op (ctx,
                             COLD_OP_STRING,
                             make_lisp_ptr ((void*) string, Lisp_String));
    }

  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  if (string->u.s.intervals)
    dump_remember_fixup_ptr_raw (
      ctx,
      offset + dump_offsetof (struct Lisp_String, u.s.intervals),
      dump_interval_tree (ctx, string->u.s.intervals, 0));

  return offset;
}

static dump_off
dump_marker (struct dump_context *ctx, const struct Lisp_Marker *marker)
{
  struct Lisp_Marker out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, marker, type);
  eassert (marker->gcmarkbit == 0);
  (void) marker->spacer; /* Do not write padding.  */
  DUMP_FIELD_COPY (&out, marker, need_adjustment);
  DUMP_FIELD_COPY (&out, marker, insertion_type);
  if (marker->buffer)
    {
      dump_field_lv_rawptr (
        ctx, &out,
        marker, &marker->buffer,
        Lisp_Vectorlike,
        WEIGHT_NORMAL);
      dump_field_lv_rawptr (
        ctx, &out,
        marker, &marker->next,
        Lisp_Misc,
        WEIGHT_STRONG);
      DUMP_FIELD_COPY (&out, marker, charpos);
      DUMP_FIELD_COPY (&out, marker, bytepos);
    }
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_overlay (struct dump_context *ctx, const struct Lisp_Overlay *overlay)
{
  struct Lisp_Overlay out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, overlay, type);
  eassert (overlay->gcmarkbit == 0);
  (void) overlay->spacer; /* Do not write padding.  */
  dump_field_lv_rawptr (ctx, &out, overlay, &overlay->next, Lisp_Misc,
                        WEIGHT_STRONG);
  dump_field_lv (ctx, &out, overlay, &overlay->start, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, overlay, &overlay->end, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, overlay, &overlay->plist, WEIGHT_STRONG);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_save_value (struct dump_context *ctx,
                 const struct Lisp_Save_Value *ptr)
{
  struct Lisp_Save_Value out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, ptr, type);
  eassert(ptr->gcmarkbit == 0);
  (void) ptr->spacer; /* Do not write padding.  */
  DUMP_FIELD_COPY (&out, ptr, save_type);
  for (int i = 0; i < SAVE_VALUE_SLOTS; i++)
    {
      switch (save_type (&out, i))
        {
        case SAVE_UNUSED:
          break;
        case SAVE_INTEGER:
          DUMP_FIELD_COPY (&out, ptr, data[i].integer);
          break;
        case SAVE_FUNCPOINTER:
          dump_field_emacs_ptr (ctx, &out, ptr, &ptr->data[i].funcpointer);
          break;
        case SAVE_OBJECT:
          dump_field_lv (ctx, &out, ptr, &ptr->data[i].object, WEIGHT_STRONG);
          break;
        case SAVE_POINTER:
          error_unsupported_dump_object(
            ctx, make_lisp_ptr ((void *) ptr, Lisp_Misc), "SAVE_POINTER");
        default:
          emacs_abort ();
        }
    }
  return dump_object_finish (ctx, &out, sizeof (out));
}

static void
dump_field_finalizer_ref (struct dump_context *ctx,
                          void *out,
                          const struct Lisp_Finalizer *finalizer,
                          struct Lisp_Finalizer *const *field)
{
  if (*field == &finalizers || *field == &doomed_finalizers)
    dump_field_emacs_ptr (ctx, out, finalizer, field);
  else
    dump_field_lv_rawptr (ctx, out, finalizer, field, Lisp_Misc,
                          WEIGHT_NORMAL);
}

static dump_off
dump_finalizer (struct dump_context *ctx,
                const struct Lisp_Finalizer *finalizer)
{
  struct Lisp_Finalizer out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, finalizer, base.type);
  eassert (finalizer->base.gcmarkbit == 0);
  (void) finalizer->base.spacer; /* Do not write padding.  */
  dump_field_finalizer_ref (ctx, &out, finalizer, &finalizer->prev);
  dump_field_finalizer_ref (ctx, &out, finalizer, &finalizer->next);
  dump_field_lv (ctx, &out, finalizer, &finalizer->function,
                 WEIGHT_NORMAL);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_misc_any (struct dump_context *ctx, struct Lisp_Misc_Any *misc_any)
{
  dump_off result;

  switch (misc_any->type)
    {
    case Lisp_Misc_Marker:
      result = dump_marker (ctx, (struct Lisp_Marker *) misc_any);
      break;

    case Lisp_Misc_Overlay:
      result = dump_overlay (ctx, (struct Lisp_Overlay *) misc_any);
      break;

    case Lisp_Misc_Save_Value:
      result = dump_save_value (ctx, (struct Lisp_Save_Value *) misc_any);
      break;

    case Lisp_Misc_Finalizer:
      result = dump_finalizer (ctx, (struct Lisp_Finalizer *) misc_any);
      break;

#ifdef HAVE_MODULES
    case Lisp_Misc_User_Ptr:
      error_unsupported_dump_object(
        ctx,
        make_lisp_ptr (misc_any, Lisp_Misc),
        "module user ptr");
      break;
#endif

    default:
      emacs_abort ();
    }

  return result;
}

static dump_off
dump_float (struct dump_context *ctx, const struct Lisp_Float *lfloat)
{
  eassert (ctx->header.cold_start);
  struct Lisp_Float out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, lfloat, u.data);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd_int (struct dump_context *ctx, const struct Lisp_Intfwd *intfwd)
{
  dump_emacs_reloc_immediate_emacs_int (ctx, intfwd->intvar, *intfwd->intvar);
  struct Lisp_Intfwd out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, intfwd, type);
  dump_field_emacs_ptr (ctx, &out, intfwd, &intfwd->intvar);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd_bool (struct dump_context *ctx, const struct Lisp_Boolfwd *boolfwd)
{
  dump_emacs_reloc_immediate_bool (ctx, boolfwd->boolvar, *boolfwd->boolvar);
  struct Lisp_Boolfwd out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, boolfwd, type);
  dump_field_emacs_ptr (ctx, &out, boolfwd, &boolfwd->boolvar);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd_obj (struct dump_context *ctx, const struct Lisp_Objfwd *objfwd)
{
  dump_emacs_reloc_to_dump_lv (ctx, objfwd->objvar, *objfwd->objvar);
  struct Lisp_Objfwd out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, objfwd, type);
  dump_field_emacs_ptr (ctx, &out, objfwd, &objfwd->objvar);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd_buffer_obj (struct dump_context *ctx,
                     const struct Lisp_Buffer_Objfwd *buffer_objfwd)
{
  struct Lisp_Buffer_Objfwd out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, buffer_objfwd, type);
  DUMP_FIELD_COPY (&out, buffer_objfwd, offset);
  dump_field_lv (ctx, &out, buffer_objfwd, &buffer_objfwd->predicate,
                 WEIGHT_NORMAL);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd_kboard_obj (struct dump_context *ctx,
                     const struct Lisp_Kboard_Objfwd *kboard_objfwd)
{
  struct Lisp_Kboard_Objfwd out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, kboard_objfwd, type);
  DUMP_FIELD_COPY (&out, kboard_objfwd, offset);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_fwd (struct dump_context *ctx, union Lisp_Fwd *fwd)
{
  dump_off offset;

  switch (XFWDTYPE (fwd))
    {
    case Lisp_Fwd_Int:
      offset = dump_fwd_int (ctx, &fwd->u_intfwd);
      break;
    case Lisp_Fwd_Bool:
      offset = dump_fwd_bool (ctx, &fwd->u_boolfwd);
      break;
    case Lisp_Fwd_Obj:
      offset = dump_fwd_obj (ctx, &fwd->u_objfwd);
      break;
    case Lisp_Fwd_Buffer_Obj:
      offset = dump_fwd_buffer_obj (ctx, &fwd->u_buffer_objfwd);
      break;
    case Lisp_Fwd_Kboard_Obj:
      offset = dump_fwd_kboard_obj (ctx, &fwd->u_kboard_objfwd);
      break;
    default:
      emacs_abort ();
    }

  return offset;
}

static dump_off
dump_blv (struct dump_context *ctx,
          const struct Lisp_Buffer_Local_Value *blv)
{
  struct Lisp_Buffer_Local_Value out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, blv, local_if_set);
  DUMP_FIELD_COPY (&out, blv, found);
  if (blv->fwd)
    dump_field_fixup_later (ctx, &out, blv, &blv->fwd);
  dump_field_lv (ctx, &out, blv, &blv->where, WEIGHT_NORMAL);
  dump_field_lv (ctx, &out, blv, &blv->defcell, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, blv, &blv->valcell, WEIGHT_STRONG);
  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  if (blv->fwd)
    dump_remember_fixup_ptr_raw (
      ctx,
      offset + dump_offsetof (struct Lisp_Buffer_Local_Value, fwd),
      dump_fwd (ctx, blv->fwd));
  return offset;
}

static dump_off
dump_recall_symbol_aux (struct dump_context *ctx, Lisp_Object symbol)
{
  Lisp_Object symbol_aux = ctx->symbol_aux;
  if (NILP (symbol_aux))
    return 0;
  return dump_off_from_lisp (
    Fgethash (symbol, symbol_aux, make_number (0)));
}

static void
dump_remember_symbol_aux (struct dump_context *ctx,
                          Lisp_Object symbol,
                          dump_off offset)
{
  Fputhash (symbol, dump_off_to_lisp (offset), ctx->symbol_aux);
}

static void
dump_pre_dump_symbol (
  struct dump_context *ctx,
  struct Lisp_Symbol *symbol)
{
  Lisp_Object symbol_lv = make_lisp_symbol (symbol);
  eassert (!dump_recall_symbol_aux (ctx, symbol_lv));
  DUMP_SET_REFERRER (ctx, symbol_lv);
  switch (symbol->u.s.redirect)
    {
    case SYMBOL_LOCALIZED:
      dump_remember_symbol_aux (
        ctx,
        symbol_lv,
        dump_blv (ctx, symbol->u.s.val.blv));
      break;
    case SYMBOL_FORWARDED:
      dump_remember_symbol_aux (
        ctx,
        symbol_lv,
        dump_fwd (ctx, symbol->u.s.val.fwd));
      break;
    default:
      break;
    }
  DUMP_CLEAR_REFERRER (ctx);
}

static dump_off
dump_symbol (struct dump_context *ctx, struct Lisp_Symbol *symbol)
{
  if (ctx->flags.defer_symbols)
    {
      /* Scan everything to which this symbol refers.  */
      struct dump_flags old_flags = ctx->flags;
      ctx->flags.dump_object_contents = false;
      ctx->flags.defer_symbols = false;
      dump_symbol (ctx, symbol);
      ctx->flags = old_flags;
      return DUMP_OBJECT_DEFERRED;
    }

  struct Lisp_Symbol out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  eassert (symbol->u.s.gcmarkbit == 0);
  DUMP_FIELD_COPY (&out, symbol, u.s.redirect);
  DUMP_FIELD_COPY (&out, symbol, u.s.trapped_write);
  DUMP_FIELD_COPY (&out, symbol, u.s.interned);
  DUMP_FIELD_COPY (&out, symbol, u.s.declared_special);
  DUMP_FIELD_COPY (&out, symbol, u.s.pinned);
  dump_field_lv (ctx, &out, symbol, &symbol->u.s.name, WEIGHT_STRONG);
  switch (symbol->u.s.redirect)
    {
    case SYMBOL_PLAINVAL:
      dump_field_lv (ctx, &out, symbol, &symbol->u.s.val.value,
                     WEIGHT_NORMAL);
      break;
    case SYMBOL_VARALIAS:
      dump_field_lv_rawptr (ctx, &out, symbol,
                            &symbol->u.s.val.alias, Lisp_Symbol,
                            WEIGHT_NORMAL);
      break;
    case SYMBOL_LOCALIZED:
      dump_field_fixup_later (ctx, &out, symbol, &symbol->u.s.val.blv);
      break;
    case SYMBOL_FORWARDED:
      dump_field_fixup_later (ctx, &out, symbol, &symbol->u.s.val.fwd);
      break;
    default:
      emacs_abort ();
    }
  dump_field_lv (ctx, &out, symbol, &symbol->u.s.function, WEIGHT_NORMAL);
  dump_field_lv (ctx, &out, symbol, &symbol->u.s.plist, WEIGHT_NORMAL);
  dump_field_lv_rawptr (ctx, &out, symbol, &symbol->u.s.next, Lisp_Symbol,
                        WEIGHT_STRONG);

  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  dump_off aux_offset;

  switch (symbol->u.s.redirect)
    {
    case SYMBOL_LOCALIZED:
      aux_offset = dump_recall_symbol_aux (ctx, make_lisp_symbol (symbol));
      dump_remember_fixup_ptr_raw (
        ctx,
        offset + dump_offsetof (struct Lisp_Symbol, u.s.val.blv),
        (aux_offset
         ? aux_offset
         : dump_blv (ctx, symbol->u.s.val.blv)));
      break;
    case SYMBOL_FORWARDED:
      aux_offset = dump_recall_symbol_aux (ctx, make_lisp_symbol (symbol));
      dump_remember_fixup_ptr_raw (
        ctx,
        offset + dump_offsetof (struct Lisp_Symbol, u.s.val.fwd),
        (aux_offset
         ? aux_offset
         : dump_fwd (ctx, symbol->u.s.val.fwd)));
      break;
    default:
      break;
    }
  return offset;
}

static dump_off
dump_vectorlike_generic (
  struct dump_context *ctx,
  const union vectorlike_header *header)
{
  const struct Lisp_Vector *v = (const struct Lisp_Vector *) header;
  ptrdiff_t size = header->size;
  enum pvec_type pvectype = PSEUDOVECTOR_TYPE (v);
  dump_off offset;

  if (size & PSEUDOVECTOR_FLAG)
    {
      /* Assert that the pseudovector contains only Lisp values ---
         but see the PVEC_SUB_CHAR_TABLE special case below.  We allow
         one extra word of non-lisp data when Lisp_Object is shorter
         than GCALIGN (e.g., on 32-bit builds) to account for
         GCALIGN-enforcing struct padding.  We can't distinguish
         between padding and some undumpable data member this way, but
         we'll count on sizeof(Lisp_Object) >= GCALIGN builds to catch
         this class of problem.
         */
      eassert (
        ((size & PSEUDOVECTOR_REST_MASK) >> PSEUDOVECTOR_REST_BITS)
        <= (sizeof (Lisp_Object) < GCALIGNMENT) ? 1 : 0);
      size &= PSEUDOVECTOR_SIZE_MASK;
    }

  dump_align_output (ctx, GCALIGNMENT);
  dump_off prefix_start_offset = ctx->offset;

  dump_off skip;
  if (pvectype == PVEC_SUB_CHAR_TABLE)
    {
      /* PVEC_SUB_CHAR_TABLE has a special case because it's a
         variable-length vector (unlike other pseudovectors) and has
         its non-Lisp data _before_ the variable-length Lisp part.  */
      const struct Lisp_Sub_Char_Table *sct =
        (const struct Lisp_Sub_Char_Table *) header;
      struct Lisp_Sub_Char_Table out;
      dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
      DUMP_FIELD_COPY (&out, sct, header.size);
      DUMP_FIELD_COPY (&out, sct, depth);
      DUMP_FIELD_COPY (&out, sct, min_char);
      offset = dump_object_finish (ctx, &out, sizeof (out));
      skip = SUB_CHAR_TABLE_OFFSET;
    }
  else
    {
      union vectorlike_header out;
      dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
      DUMP_FIELD_COPY (&out, header, size);
      offset = dump_object_finish (ctx, &out, sizeof (out));
      skip = 0;
    }

  /* dump_object_start isn't what records conservative-GC object
     starts --- dump_object_1 does --- so the hack below of using
     dump_object_start for each vector word doesn't cause GC problems
     at runtime.  */

  dump_off prefix_size = ctx->offset - prefix_start_offset;
  eassert (prefix_size > 0);
  dump_off skip_start = ptrdiff_t_to_dump_off (
    (char*) &v->contents[skip] - (char*) v);
  eassert (skip_start >= prefix_size);
  dump_write_zero (ctx, skip_start - prefix_size);
  for (dump_off i = skip; i < size; ++i)
    {
      Lisp_Object out;
      const Lisp_Object *vslot = &v->contents[i];
      eassert (ctx->offset % sizeof (out) == 0);
      dump_object_start (ctx, 1, &out, sizeof (out));
      dump_field_lv (ctx, &out, vslot, vslot, WEIGHT_STRONG);
      dump_object_finish (ctx, &out, sizeof (out));
    }

  if (sizeof (Lisp_Object) < GCALIGNMENT)
    dump_write_zero (ctx, GCALIGNMENT - (ctx->offset % GCALIGNMENT));

  return offset;
}

static void
dump_object_start_pseudovector (
  struct dump_context *ctx,
  union vectorlike_header *out_hdr,
  dump_off out_size,
  const union vectorlike_header *in_hdr)
{
  const struct Lisp_Vector *in = (const struct Lisp_Vector *) in_hdr;
  struct Lisp_Vector *out = (struct Lisp_Vector *) out_hdr;

  eassert (vector_nbytes ((struct Lisp_Vector *) in) == out_size);

  dump_object_start (ctx, GCALIGNMENT, out, out_size);
  DUMP_FIELD_COPY (out, in, header);
  ptrdiff_t size = in->header.size;
  eassert (size & PSEUDOVECTOR_FLAG);
  size &= PSEUDOVECTOR_SIZE_MASK;
  for (ptrdiff_t i = 0; i < size; ++i)
    dump_field_lv (ctx, out, in, &in->contents[i], WEIGHT_STRONG);
}

/* Determine whether the hash table's hash order is stable
   across dump and load.  If it is, we don't have to trigger
   a rehash on access.  */
static bool
dump_hash_table_stable_p (const struct Lisp_Hash_Table *hash)
{
  bool is_eql = hash->test.hashfn == hashfn_eql;
  bool is_equal = hash->test.hashfn == hashfn_equal;
  ptrdiff_t size = HASH_TABLE_SIZE (hash);
  for (ptrdiff_t i = 0; i < size; ++i)
    if (!NILP (HASH_HASH (hash, i)))
      {
        Lisp_Object key =  HASH_KEY (hash, i);
        bool key_stable = (dump_builtin_symbol_p (key) ||
                           INTEGERP (key) ||
                           (is_equal && STRINGP (key)) ||
                           ((is_equal || is_eql) && FLOATP (key)));
        if (!key_stable)
          return false;
      }

  return true;
}

/* Return a list of (KEY . VALUE) pairs in the given hash table.  */
static Lisp_Object
hash_table_contents (Lisp_Object table)
{
  Lisp_Object contents = Qnil;
  struct Lisp_Hash_Table *h = XHASH_TABLE (table);
  for (ptrdiff_t i = 0; i < HASH_TABLE_SIZE (h); ++i)
    if (!NILP (HASH_HASH (h, i)))
      dump_push (&contents, Fcons (HASH_KEY (h, i), HASH_VALUE (h, i)));
  return Fnreverse (contents);
}

/* Copy the given hash table, rehash it, and make sure that we can
   look up all the values in the original.  */
static void
check_hash_table_rehash (Lisp_Object table_orig)
{
  Lisp_Object table_rehashed = Fcopy_hash_table (table_orig);
  eassert (XHASH_TABLE (table_rehashed)->count >= 0);
  XHASH_TABLE (table_rehashed)->count *= -1;
  eassert (XHASH_TABLE (table_rehashed)->count <= 0);
  hash_rehash_if_needed (XHASH_TABLE (table_rehashed));
  eassert (XHASH_TABLE (table_rehashed)->count >= 0);
  Lisp_Object expected_contents = hash_table_contents (table_orig);
  while (!NILP (expected_contents))
    {
      Lisp_Object key_value_pair = dump_pop (&expected_contents);
      Lisp_Object key = XCAR (key_value_pair);
      Lisp_Object expected_value = XCDR (key_value_pair);
      Lisp_Object found_value = Fgethash (
        key,
        table_rehashed,
        Qdump_emacs_portable__sort_predicate_copied /* arbitrary */);
      eassert (EQ (expected_value, found_value));
      Fremhash (key, table_rehashed);
    }

  eassert (EQ (Fhash_table_count (table_rehashed),
               make_number (0)));
}

static dump_off
dump_hash_table (struct dump_context *ctx,
                 const struct Lisp_Hash_Table *hash_in)
{
  bool is_stable = dump_hash_table_stable_p (hash_in);
  /* If the hash table is likely to be modified in memory (either
     because we need to rehash, and thus toggle hash->count, or
     because we need to assemble a list of weak tables) punt the hash
     table to the end of the dump, where we can lump all such hash
     tables together.  */
  if (!(is_stable || !NILP (hash_in->weak)) &&
      ctx->flags.defer_hash_tables)
    {
      /* We still want to dump the actual keys and values now.  */
      dump_enqueue_object (ctx, hash_in->key_and_value, WEIGHT_NONE);
      /* We'll get to the rest later.  */
      dump_push (&ctx->deferred_hash_tables,
                 make_lisp_ptr ((void*)hash_in, Lisp_Vectorlike));
      return DUMP_OBJECT_DEFERRED;
    }

  if (PDUMPER_CHECK_REHASHING)
    check_hash_table_rehash (make_lisp_ptr ((void*)hash_in, Lisp_Vectorlike));

  struct Lisp_Hash_Table hash_munged = *hash_in;
  struct Lisp_Hash_Table *hash = &hash_munged;

  /* Remember to rehash this hash table on first access.  After a
     dump reload, the hash table values will have changed, so we'll
     need to rebuild the index.

     TODO: for EQ and EQL hash tables, it should be possible to rehash
     here using the preferred load address of the dump, eliminating
     the need to rehash-on-access if we can load the dump where we
     want.  */
  if (hash->count > 0 && !is_stable)
    hash->count = -hash->count;

  struct Lisp_Hash_Table out;
  dump_object_start_pseudovector (
    ctx, &out.header, sizeof (out), &hash->header);
  DUMP_FIELD_COPY (&out, hash, count);
  DUMP_FIELD_COPY (&out, hash, next_free);
  DUMP_FIELD_COPY (&out, hash, pure);
  DUMP_FIELD_COPY (&out, hash, rehash_threshold);
  DUMP_FIELD_COPY (&out, hash, rehash_size);
  dump_field_lv (ctx, &out, hash, &hash->key_and_value, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, hash, &hash->test.name, WEIGHT_STRONG);
  dump_field_lv (ctx, &out, hash, &hash->test.user_hash_function,
                 WEIGHT_STRONG);
  dump_field_lv (ctx, &out, hash, &hash->test.user_cmp_function,
                 WEIGHT_STRONG);
  dump_field_emacs_ptr (ctx, &out, hash, &hash->test.cmpfn);
  dump_field_emacs_ptr (ctx, &out, hash, &hash->test.hashfn);
  eassert (hash->next_weak == NULL);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static dump_off
dump_buffer (struct dump_context *ctx, const struct buffer *in_buffer)
{
  struct buffer munged_buffer = *in_buffer;
  struct buffer *buffer = &munged_buffer;

  /* Clear some buffer state for correctness upon load.  */
  if (buffer->base_buffer == NULL)
    buffer->window_count = 0;
  else
    eassert (buffer->window_count == -1);
  buffer->last_selected_window_ = Qnil;
  buffer->display_count_ = make_number (0);
  buffer->clip_changed = 0;
  buffer->last_window_start = -1;
  buffer->point_before_scroll_ = Qnil;

  dump_off base_offset = 0;
  if (buffer->base_buffer)
    {
      eassert (buffer->base_buffer->base_buffer == NULL);
      base_offset = dump_object_for_offset (
        ctx,
        make_lisp_ptr (buffer->base_buffer, Lisp_Vectorlike));
    }

  eassert ((base_offset == 0 && buffer->text == &in_buffer->own_text) ||
           (base_offset > 0 && buffer->text != &in_buffer->own_text));

  struct buffer out;
  dump_object_start_pseudovector (
    ctx, &out.header, sizeof (out), &buffer->header);
  if (base_offset == 0)
    base_offset = ctx->obj_offset;
  eassert (base_offset > 0);
  if (buffer->base_buffer == NULL)
    {
      eassert (base_offset == ctx->obj_offset);

      if (BUFFER_LIVE_P (buffer))
        {
          dump_field_fixup_later (ctx, &out, buffer, &buffer->own_text.beg);
          dump_remember_cold_op (
            ctx,
            COLD_OP_BUFFER,
            make_lisp_ptr ((void*) in_buffer, Lisp_Vectorlike));
        }
      else
        eassert (buffer->own_text.beg == NULL);

      DUMP_FIELD_COPY (&out, buffer, own_text.gpt);
      DUMP_FIELD_COPY (&out, buffer, own_text.z);
      DUMP_FIELD_COPY (&out, buffer, own_text.gpt_byte);
      DUMP_FIELD_COPY (&out, buffer, own_text.z_byte);
      DUMP_FIELD_COPY (&out, buffer, own_text.gap_size);
      DUMP_FIELD_COPY (&out, buffer, own_text.modiff);
      DUMP_FIELD_COPY (&out, buffer, own_text.chars_modiff);
      DUMP_FIELD_COPY (&out, buffer, own_text.save_modiff);
      DUMP_FIELD_COPY (&out, buffer, own_text.overlay_modiff);
      DUMP_FIELD_COPY (&out, buffer, own_text.compact);
      DUMP_FIELD_COPY (&out, buffer, own_text.beg_unchanged);
      DUMP_FIELD_COPY (&out, buffer, own_text.end_unchanged);
      DUMP_FIELD_COPY (&out, buffer, own_text.unchanged_modified);
      DUMP_FIELD_COPY (&out, buffer, own_text.overlay_unchanged_modified);
      if (buffer->own_text.intervals)
        dump_field_fixup_later (ctx, &out, buffer, &buffer->own_text.intervals);
      dump_field_lv_rawptr (ctx, &out, buffer, &buffer->own_text.markers,
                            Lisp_Misc, WEIGHT_NORMAL);
      DUMP_FIELD_COPY (&out, buffer, own_text.inhibit_shrinking);
      DUMP_FIELD_COPY (&out, buffer, own_text.redisplay);
    }

  eassert (ctx->obj_offset > 0);
  dump_remember_fixup_ptr_raw (
    ctx,
    ctx->obj_offset + dump_offsetof (struct buffer, text),
    base_offset + dump_offsetof (struct buffer, own_text));

  dump_field_lv_rawptr (ctx, &out, buffer, &buffer->next,
                        Lisp_Vectorlike, WEIGHT_NORMAL);
  DUMP_FIELD_COPY (&out, buffer, pt);
  DUMP_FIELD_COPY (&out, buffer, pt_byte);
  DUMP_FIELD_COPY (&out, buffer, begv);
  DUMP_FIELD_COPY (&out, buffer, begv_byte);
  DUMP_FIELD_COPY (&out, buffer, zv);
  DUMP_FIELD_COPY (&out, buffer, zv_byte);

  if (buffer->base_buffer)
    {
      eassert (ctx->obj_offset != base_offset);
      dump_field_ptr_to_dump_offset (
        ctx, &out, buffer, &buffer->base_buffer,
        base_offset);
    }

  DUMP_FIELD_COPY (&out, buffer, indirections);
  DUMP_FIELD_COPY (&out, buffer, window_count);

  memcpy (&out.local_flags,
          &buffer->local_flags,
          sizeof (out.local_flags));
  DUMP_FIELD_COPY (&out, buffer, modtime);
  DUMP_FIELD_COPY (&out, buffer, modtime_size);
  DUMP_FIELD_COPY (&out, buffer, auto_save_modified);
  DUMP_FIELD_COPY (&out, buffer, display_error_modiff);
  DUMP_FIELD_COPY (&out, buffer, auto_save_failure_time);
  DUMP_FIELD_COPY (&out, buffer, last_window_start);

  /* Not worth serializing these caches.  TODO: really? */
  out.newline_cache = NULL;
  out.width_run_cache = NULL;
  out.bidi_paragraph_cache = NULL;

  DUMP_FIELD_COPY (&out, buffer, prevent_redisplay_optimizations_p);
  DUMP_FIELD_COPY (&out, buffer, clip_changed);

  dump_field_lv_rawptr (ctx, &out, buffer, &buffer->overlays_before,
                        Lisp_Misc, WEIGHT_NORMAL);

  dump_field_lv_rawptr (ctx, &out, buffer, &buffer->overlays_after,
                        Lisp_Misc, WEIGHT_NORMAL);

  DUMP_FIELD_COPY (&out, buffer, overlay_center);
  dump_field_lv (ctx, &out, buffer, &buffer->undo_list_,
                 WEIGHT_STRONG);
  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  if (!buffer->base_buffer && buffer->own_text.intervals)
    dump_remember_fixup_ptr_raw (
      ctx,
      offset + dump_offsetof (struct buffer, own_text.intervals),
      dump_interval_tree (ctx, buffer->own_text.intervals, 0));

  return offset;
}

static dump_off
dump_bool_vector (struct dump_context *ctx, const struct Lisp_Vector *v)
{
  /* No relocation needed, so we don't need dump_object_start.  */
  dump_align_output (ctx, GCALIGNMENT);
  eassert (ctx->offset >= ctx->header.cold_start);
  dump_off offset = ctx->offset;
  ptrdiff_t nbytes = vector_nbytes ((struct Lisp_Vector *) v);
  if (nbytes > DUMP_OFF_T_MAX)
    error ("vector too large");
  dump_write (ctx, v, ptrdiff_t_to_dump_off (nbytes));
  return offset;
}

static dump_off
dump_subr (struct dump_context *ctx, const struct Lisp_Subr *subr)
{
  struct Lisp_Subr out;
  dump_object_start (ctx, GCALIGNMENT, &out, sizeof (out));
  DUMP_FIELD_COPY (&out, subr, header.size);
  dump_field_emacs_ptr (ctx, &out, subr, &subr->function.a0);
  DUMP_FIELD_COPY (&out, subr, min_args);
  DUMP_FIELD_COPY (&out, subr, max_args);
  dump_field_emacs_ptr (ctx, &out, subr, &subr->symbol_name);
  dump_field_emacs_ptr (ctx, &out, subr, &subr->intspec);
  DUMP_FIELD_COPY (&out, subr, doc);
  return dump_object_finish (ctx, &out, sizeof (out));
}

static void
fill_pseudovec (union vectorlike_header *header, Lisp_Object item)
{
  struct Lisp_Vector *v = (struct Lisp_Vector *) header;
  eassert (v->header.size & PSEUDOVECTOR_FLAG);
  ptrdiff_t size = v->header.size & PSEUDOVECTOR_SIZE_MASK;
  for (ptrdiff_t idx = 0; idx < size; idx++)
    v->contents[idx] = item;
}

static dump_off
dump_nilled_pseudovec (struct dump_context *ctx,
                       const union vectorlike_header *in)
{
  if (vector_nbytes ((struct Lisp_Vector *) in) > DUMP_OFF_T_MAX)
    error ("pseudovector too large");
  dump_off nbytes = ptrdiff_t_to_dump_off (
    vector_nbytes ((struct Lisp_Vector *) in));
  union vectorlike_header *in_nilled = alloca (nbytes);
  memset (in_nilled, 0, nbytes);
  in_nilled->size = in->size;
  fill_pseudovec (in_nilled, Qnil);
  union vectorlike_header *out = alloca (nbytes);
  memset (out, 0, nbytes);
  dump_object_start_pseudovector (ctx, out, nbytes, in_nilled);
  return dump_object_finish (ctx, out, nbytes);
}

static dump_off
dump_vectorlike (struct dump_context *ctx, const struct Lisp_Vector *v)
{
  dump_off offset;
  Lisp_Object lv = make_lisp_ptr ((void *) v, Lisp_Vectorlike);
  switch (PSEUDOVECTOR_TYPE (v))
    {
    case PVEC_FONT:
      /* There are three kinds of font objects that all use PVEC_FONT,
         distinguished by their size.  Font specs and entities are
         harmless data carriers that we can dump like other Lisp
         objects.  Fonts themselves are window-system-specific and
         need to be recreated on each startup.  */
      if ((v->header.size & PSEUDOVECTOR_SIZE_MASK) != FONT_SPEC_MAX &&
          (v->header.size & PSEUDOVECTOR_SIZE_MASK) != FONT_ENTITY_MAX)
        error_unsupported_dump_object(ctx, lv, "font");
      FALLTHROUGH;
    case PVEC_NORMAL_VECTOR:
    case PVEC_COMPILED:
    case PVEC_CHAR_TABLE:
    case PVEC_SUB_CHAR_TABLE:
    case PVEC_RECORD:
      offset = dump_vectorlike_generic (ctx, &v->header);
      break;
    case PVEC_BOOL_VECTOR:
      offset = dump_bool_vector(ctx, v);
      break;
    case PVEC_HASH_TABLE:
      offset = dump_hash_table (ctx, (struct Lisp_Hash_Table *) v);
      break;
    case PVEC_BUFFER:
      offset = dump_buffer (ctx, (struct buffer *) v);
      break;
    case PVEC_SUBR:
      offset = dump_subr (ctx, (const struct Lisp_Subr *) v);
      break;
    case PVEC_FRAME:
    case PVEC_WINDOW:
    case PVEC_PROCESS:
    case PVEC_TERMINAL:
      offset = dump_nilled_pseudovec (ctx, &v->header);
      break;
    case PVEC_WINDOW_CONFIGURATION:
      error_unsupported_dump_object (ctx, lv, "window configuration");
    case PVEC_OTHER:
      error_unsupported_dump_object (ctx, lv, "other?!");
    case PVEC_XWIDGET:
      error_unsupported_dump_object (ctx, lv, "xwidget");
    case PVEC_XWIDGET_VIEW:
      error_unsupported_dump_object (ctx, lv, "xwidget view");
    case PVEC_THREAD:
    case PVEC_MUTEX:
    case PVEC_CONDVAR:
      error_unsupported_dump_object (ctx, lv, "threading object");
    case PVEC_MODULE_FUNCTION:
      error_unsupported_dump_object (ctx, lv, "module function");
    default:
      error_unsupported_dump_object(ctx, lv, "weird pseudovector");
    }

  return offset;
}

/* Internal guts of dump_object().

   This function has the same contract as dump_object(), except that
   it doesn't defer copying dumped objects (instead, dumping them
   immediately) and always returns a valid offset.

   Called directly by dump_copied_objects() to bypass dump_object()'s
   check for copied objects.
 */
static dump_off
dump_object_1 (struct dump_context *ctx, Lisp_Object object)
{
#ifdef ENABLE_CHECKING
  /* Vdead is extern only when ENABLE_CHECKING.  */
  eassert (!EQ (object, Vdead));
#endif

  dump_off offset = dump_recall_object (ctx, object);
  if (offset > 0)
    {
      /* Object already dumped.  */
    }
  else
    {
      /* Object needs to be dumped.  */
      DUMP_SET_REFERRER (ctx, object);
      switch (XTYPE (object))
        {
        case Lisp_String:
          offset = dump_string (ctx, XSTRING (object));
          break;
        case Lisp_Vectorlike:
          offset = dump_vectorlike (ctx, XVECTOR (object));
          break;
        case Lisp_Symbol:
          offset = dump_symbol (ctx, XSYMBOL (object));
          break;
        case Lisp_Misc:
          offset = dump_misc_any (ctx, XMISCANY (object));
          break;
        case Lisp_Cons:
          offset = dump_cons (ctx, XCONS (object));
          break;
        case Lisp_Float:
          offset = dump_float (ctx, XFLOAT (object));
          break;
        case_Lisp_Int:
          eassert ("should not be dumping int: is self-representing" && 0);
        default:
          emacs_abort ();
        }
      DUMP_CLEAR_REFERRER (ctx);

      /* offset can be < 0 if we've deferred an object --- e.g., a
         hash table.  */
      if (ctx->flags.dump_object_contents && offset > 0)
        {
          eassert (offset % (1<<DUMP_RELOC_ALIGNMENT_BITS) == 0);
          dump_remember_object (ctx, object, offset);
          if (ctx->flags.dump_object_starts)
            dump_push (&ctx->object_starts,
                       list2 (dump_off_to_lisp (XTYPE (object)),
                              dump_off_to_lisp (offset)));
        }
    }

  return offset;
}

/* Add an object to the dump.

   CTX is the dump context; OBJECT is the object to add.  Normally,
   return OFFSET, the location (in bytes, from the start of the dump
   file) where we wrote the object.  Valid OFFSETs are always greater
   than zero.

   If we've already dumped an object, return the location where we put
   it: dump_object is idempotent.

   The object may not be self-representing.  Self-representing objects
   are immediate values rather than tagged pointers to Lisp heap
   structures and so have no individual representation in the Lisp
   heap dump.

   May also return DUMP_OBJECT_DEFERRED if we "dumped" the
   object by remembering to process it specially later.  In this case,
   we don't have a valid offset.  Call dump_object_for_offset if you
   need a valid offset for an object.
 */
static dump_off
dump_object (struct dump_context *ctx, Lisp_Object object)
{
  dump_off result;

  if (dump_object_emacs_ptr (object) == NULL)
    {
      eassert (!dump_object_self_representing_p (object));
      result = dump_object_1 (ctx, object);
    }
  else
    {
      /* Objects that are part of the Emacs image need to be copied
         into that image from the dump image, so handle them
         specially.  */
      result = dump_recall_object (ctx, object);

      /* We should not have written a copied object normally due to
         the above constraint.  This object must either be on some
         queue or not yet seen.  */
      eassert (result == DUMP_OBJECT_NOT_SEEN ||
               result == DUMP_OBJECT_ON_NORMAL_QUEUE ||
               result == DUMP_OBJECT_DEFERRED);
      if (result != DUMP_OBJECT_DEFERRED)
        {
          /* Remember to dump this object in the special copied
             objects section.  */
          dump_push (&ctx->copied_queue, object);
          result = DUMP_OBJECT_DEFERRED;
          dump_remember_object (ctx, object, result);

          /* But scan the object for objects to which it refers.  */
          struct dump_flags old_flags = ctx->flags;
          ctx->flags.dump_object_contents = false;
          dump_object_1 (ctx, object);
          ctx->flags = old_flags;
        }
    }

  return result;
}

/* Like dump_object(), but assert that we get a valid offset.  */
static dump_off
dump_object_for_offset (struct dump_context *ctx, Lisp_Object object)
{
  dump_off offset = dump_object (ctx, object);
  eassert (offset > 0);
  return offset;
}

static dump_off
dump_charset (struct dump_context *ctx, int cs_i)
{
  const struct charset *cs = charset_table + cs_i;
  struct charset out;
  dump_object_start (ctx, sizeof (int), &out, sizeof (out));
  DUMP_FIELD_COPY (&out, cs, id);
  DUMP_FIELD_COPY (&out, cs, hash_index);
  DUMP_FIELD_COPY (&out, cs, dimension);
  memcpy (out.code_space, &cs->code_space, sizeof (cs->code_space));
  if (cs->code_space_mask)
    dump_field_fixup_later (ctx, &out, cs, &cs->code_space_mask);
  DUMP_FIELD_COPY (&out, cs, code_linear_p);
  DUMP_FIELD_COPY (&out, cs, iso_chars_96);
  DUMP_FIELD_COPY (&out, cs, ascii_compatible_p);
  DUMP_FIELD_COPY (&out, cs, supplementary_p);
  DUMP_FIELD_COPY (&out, cs, compact_codes_p);
  DUMP_FIELD_COPY (&out, cs, unified_p);
  DUMP_FIELD_COPY (&out, cs, iso_final);
  DUMP_FIELD_COPY (&out, cs, iso_revision);
  DUMP_FIELD_COPY (&out, cs, emacs_mule_id);
  DUMP_FIELD_COPY (&out, cs, method);
  DUMP_FIELD_COPY (&out, cs, min_code);
  DUMP_FIELD_COPY (&out, cs, max_code);
  DUMP_FIELD_COPY (&out, cs, char_index_offset);
  DUMP_FIELD_COPY (&out, cs, min_char);
  DUMP_FIELD_COPY (&out, cs, max_char);
  DUMP_FIELD_COPY (&out, cs, invalid_code);
  memcpy (out.fast_map, &cs->fast_map, sizeof (cs->fast_map));
  DUMP_FIELD_COPY (&out, cs, code_offset);
  dump_off offset = dump_object_finish (ctx, &out, sizeof (out));
  if (cs->code_space_mask)
    dump_remember_cold_op (ctx, COLD_OP_CHARSET,
                           Fcons (dump_off_to_lisp (cs_i),
                                  dump_off_to_lisp (offset)));
  return offset;
}

static dump_off
dump_charset_table (struct dump_context *ctx)
{
  dump_align_output (ctx, GCALIGNMENT);
  dump_off offset = ctx->offset;
  for (int i = 0; i < charset_table_used; ++i)
    dump_charset (ctx, i);
  dump_emacs_reloc_to_dump_ptr_raw (ctx, &charset_table, offset);
  dump_emacs_reloc_immediate_int (
    ctx, &charset_table_used, charset_table_used);
  dump_emacs_reloc_immediate_ptrdiff_t (
    ctx, &charset_table_size, charset_table_used);
  return offset;
}

static void
dump_finalizer_list_head_ptr (struct dump_context *ctx,
                              struct Lisp_Finalizer **ptr)
{
  struct Lisp_Finalizer *value = *ptr;
  if (value != &finalizers && value != &doomed_finalizers)
    dump_emacs_reloc_to_dump_ptr_raw (
      ctx, ptr,
      dump_object_for_offset (ctx, make_lisp_ptr (value, Lisp_Misc)));
}

static void
dump_metadata_for_pdumper (struct dump_context *ctx)
{
  for (int i = 0; i < nr_dump_hooks; ++i)
    dump_emacs_reloc_to_emacs_ptr_raw (ctx, &dump_hooks[i], dump_hooks[i]);
  dump_emacs_reloc_immediate_int (ctx, &nr_dump_hooks, nr_dump_hooks);

  for (int i = 0; i < nr_remembered_data; ++i)
    {
      dump_emacs_reloc_to_emacs_ptr_raw (
        ctx,
        &remembered_data[i].mem,
        remembered_data[i].mem);
      dump_emacs_reloc_immediate_int (
        ctx,
        &remembered_data[i].sz,
        remembered_data[i].sz);
    }
  dump_emacs_reloc_immediate_int (
    ctx,
    &nr_remembered_data,
    nr_remembered_data);
}

/* Sort the list of copied objects in CTX.  */
static void
dump_sort_copied_objects (struct dump_context *ctx)
{
  /* Sort the objects into the order in which they'll appear in the
     Emacs: this way, on startup, we'll do both the IO from the dump
     file and the copy into Emacs in-order, where prefetch will be
     most effective.  */
  ctx->copied_queue =
    Fsort (Fnreverse (
             ctx->copied_queue),
           Qdump_emacs_portable__sort_predicate_copied);
}

/* Dump parts of copied objects we need at runtime.  */
static void
dump_hot_parts_of_discardable_objects (struct dump_context *ctx)
{
  Lisp_Object copied_queue = ctx->copied_queue;
  while (!NILP (copied_queue))
    {
      Lisp_Object copied = dump_pop (&copied_queue);
      if (SYMBOLP (copied))
        {
          eassert (dump_builtin_symbol_p (copied));
          dump_pre_dump_symbol (ctx, XSYMBOL (copied));
        }
    }
}

static void
dump_copied_objects (struct dump_context *ctx)
{
  Lisp_Object copied_queue = ctx->copied_queue;
  ctx->copied_queue = Qnil;
  /* Dump the objects and generate a copy relocation for each.  Don't
     bother trying to reduce the number of copy relocations we
     generate: we'll merge adjacent copy relocations upon output.
     The overfall result is that to the greatest extent possible while
     maintaining strictly increasing address order, we copy into Emacs
     in nice big chunks.  */
  while (!NILP (copied_queue))
    {
      Lisp_Object copied = dump_pop (&copied_queue);
      void *optr = dump_object_emacs_ptr (copied);
      eassert (optr != NULL);

      /* We should have already fully scanned these objects, so assert
         that we're not adding more entries to the dump queue.  */
      struct dump_flags old_flags = ctx->flags;
      ctx->flags.assert_already_seen = true;
      dump_off start_offset = dump_object_1 (ctx, copied);
      ctx->flags = old_flags;

      dump_off size = ctx->offset - start_offset;
      dump_emacs_reloc_copy_from_dump (ctx, start_offset, optr, size);
    }
}

static void
dump_cold_string (struct dump_context *ctx, Lisp_Object string)
{
  /* Dump string contents.  */
  dump_off string_offset = dump_recall_object (ctx, string);
  eassert (string_offset > 0);
  if (SBYTES (string) > DUMP_OFF_T_MAX - 1)
    error ("string too large");
  dump_off total_size = ptrdiff_t_to_dump_off (SBYTES (string) + 1);
  eassert (total_size > 0);
  dump_remember_fixup_ptr_raw (
    ctx,
    string_offset + dump_offsetof (struct Lisp_String, u.s.data),
    ctx->offset);
  dump_write (ctx, XSTRING (string)->u.s.data, total_size);
}

static void
dump_cold_charset (struct dump_context *ctx, Lisp_Object data)
{
  /* Dump charset lookup tables.  */
  ALLOW_IMPLICIT_CONVERSION;
  int cs_i = XFASTINT (XCAR (data));
  DISALLOW_IMPLICIT_CONVERSION;
  dump_off cs_dump_offset = dump_off_from_lisp (XCDR (data));
  dump_remember_fixup_ptr_raw (
    ctx,
    cs_dump_offset + dump_offsetof (struct charset, code_space_mask),
    ctx->offset);
  struct charset *cs = charset_table + cs_i;
  dump_write (ctx, cs->code_space_mask, 256);
}

static void
dump_cold_buffer (struct dump_context *ctx, Lisp_Object data)
{
  /* Dump buffer text.  */
  dump_off buffer_offset = dump_recall_object (ctx, data);
  eassert (buffer_offset > 0);
  struct buffer *b = XBUFFER (data);
  eassert (b->text == &b->own_text);
  /* Zero the gap so we don't dump uninitialized bytes.  */
  memset (BUF_GPT_ADDR (b), 0, BUF_GAP_SIZE (b));
  /* See buffer.c for this calculation.  */
  ptrdiff_t nbytes =
    BUF_Z_BYTE (b)
    - BUF_BEG_BYTE (b)
    + BUF_GAP_SIZE (b)
    + 1;
  if (nbytes > DUMP_OFF_T_MAX)
    error ("buffer too large");
  dump_remember_fixup_ptr_raw (
    ctx,
    buffer_offset + dump_offsetof (struct buffer, own_text.beg),
    ctx->offset);
  dump_write (ctx, b->own_text.beg, ptrdiff_t_to_dump_off (nbytes));
}

static void
dump_cold_data (struct dump_context *ctx)
{
  Lisp_Object cold_queue = Fnreverse (ctx->cold_queue);
  ctx->cold_queue = Qnil;

  /* We should have already scanned all objects to which our cold
     objects refer, so die if an object points to something we haven't
     seen.  */
  struct dump_flags old_flags = ctx->flags;
  ctx->flags.assert_already_seen = true;

  while (!NILP (cold_queue))
    {
      Lisp_Object item = dump_pop (&cold_queue);
      enum cold_op op = (enum cold_op) XFASTINT (XCAR (item));
      Lisp_Object data = XCDR (item);
      switch (op)
        {
        case COLD_OP_STRING:
          dump_cold_string (ctx, data);
          break;
        case COLD_OP_CHARSET:
          dump_cold_charset (ctx, data);
          break;
        case COLD_OP_BUFFER:
          dump_cold_buffer (ctx, data);
          break;
        case COLD_OP_OBJECT:
          /* Objects that we can put in the cold section
             must not refer to other objects.  */
          eassert (dump_queue_empty_p (&ctx->dump_queue));
          eassert (ctx->flags.dump_object_contents);
          dump_object (ctx, data);
          eassert (dump_queue_empty_p (&ctx->dump_queue));
          break;
        default:
          emacs_abort ();
        }
    }

  ctx->flags = old_flags;
}

static void
read_ptr_raw_and_lv (const void *mem,
                     enum Lisp_Type type,
                     void **out_ptr,
                     Lisp_Object *out_lv)
{
  memcpy (out_ptr, mem, sizeof (*out_ptr));
  if (*out_ptr != NULL)
    {
      switch (type)
        {
        case Lisp_Symbol:
          *out_lv = make_lisp_symbol (*out_ptr);
          break;
        case Lisp_Misc:
        case Lisp_String:
        case Lisp_Vectorlike:
        case Lisp_Cons:
        case Lisp_Float:
          *out_lv = make_lisp_ptr (*out_ptr, type);
          break;
        default:
          emacs_abort ();
        }
    }
}

/* Enqueue for dumping objects referenced by static non-Lisp_Object
   pointers inside Emacs.  */
static void
dump_user_remembered_data_hot (struct dump_context *ctx)
{
  for (int i = 0; i < nr_remembered_data; ++i)
    {
      void *mem = remembered_data[i].mem;
      int sz = remembered_data[i].sz;
      if (sz <= 0)
        {
          enum Lisp_Type type = -sz;
          void *value;
          Lisp_Object lv;
          read_ptr_raw_and_lv (mem, type, &value, &lv);
          if (value != NULL)
            {
              DUMP_SET_REFERRER (ctx, dump_ptr_referrer ("user data", mem));
              dump_enqueue_object (ctx, lv, WEIGHT_NONE);
              DUMP_CLEAR_REFERRER (ctx);
            }
        }
    }
}

/* Dump user-specified non-relocated data.  */
static void
dump_user_remembered_data_cold (struct dump_context *ctx)
{
  for (int i = 0; i < nr_remembered_data; ++i)
    {
      void *mem = remembered_data[i].mem;
      int sz = remembered_data[i].sz;
      if (sz > 0)
        {
          /* Scalar: try to inline the value into the relocation if
             it's small enough; if it's bigger than we can fit in a
             relocation, we have to copy the data into the dump proper
             and issue a copy relocation.  */
          if (sz <= sizeof (intmax_t))
            dump_emacs_reloc_immediate (ctx, mem, mem, sz);
          else
            {
              dump_emacs_reloc_copy_from_dump (ctx, ctx->offset, mem, sz);
              dump_write (ctx, mem, sz);
            }
        }
      else
        {
          /* *mem is a raw pointer to a Lisp object of some sort.
             The object to which it points should have already been
             dumped by dump_user_remembered_data_hot.  */
          void *value;
          Lisp_Object lv;
          enum Lisp_Type type = -sz;
          read_ptr_raw_and_lv (mem, type, &value, &lv);
          if (value == NULL)
            /* We can't just ignore NULL: the variable might have
               transitioned from non-NULL to NULL, and we want to
               record this fact.  */
            dump_emacs_reloc_immediate_ptrdiff_t (ctx, mem, 0);
          else
            {
              if (dump_object_emacs_ptr (lv) != NULL)
                {
                  /* We have situation like this:

                     static Lisp_Symbol *foo;
                     ...
                     foo = XSYMBOL(Qt);
                     ...
                     pdumper_remember_lv_ptr_raw (&foo, Lisp_Symbol);

                     Built-in symbols like Qt aren't in the dump!
                     They're actually in Emacs proper.  We need a
                     special case to point this value back at Emacs
                     instead of to something in the dump that
                     isn't there.

                     An analogous situation applies to subrs, since
                     Lisp_Subr structures always live in Emacs, not
                     the dump.

                  */
                  dump_emacs_reloc_to_emacs_ptr_raw (
                    ctx, mem, dump_object_emacs_ptr (lv));
                }
              else
                {
                  eassert (!dump_object_self_representing_p (lv));
                  dump_off dump_offset = dump_recall_object (ctx, lv);
                  if (dump_offset <= 0)
                    error ("raw-pointer object not dumped?!");
                  dump_emacs_reloc_to_dump_ptr_raw (ctx, mem, dump_offset);
                }
            }
        }
    }
}

static void
dump_unwind_cleanup (void *data)
{
  struct dump_context *ctx = data;
  if (ctx->fd >= 0)
    emacs_close (ctx->fd);
#ifdef REL_ALLOC
  if (ctx->blocked_ralloc)
    r_alloc_inhibit_buffer_relocation (0);
#endif
  Vpurify_flag = ctx->old_purify_flag;
  unblock_input ();
}

static void
dump_do_fixup (struct dump_context *ctx, Lisp_Object fixup)
{
  enum dump_fixup_type type =
    (enum dump_fixup_type) XFASTINT (XCAR (fixup));
  fixup = XCDR (fixup);
  dump_off dump_fixup_offset = dump_off_from_lisp (XCAR (fixup));
  fixup = XCDR (fixup);
  Lisp_Object arg = XCAR (fixup);
  eassert (NILP (XCDR (fixup)));
  dump_seek (ctx, dump_fixup_offset);
  intptr_t dump_value;
  bool do_write = true;
  switch (type)
    {
    case DUMP_FIXUP_LISP_OBJECT:
    case DUMP_FIXUP_LISP_OBJECT_RAW:
      /* Dump wants a pointer to a Lisp object.
         If DUMP_FIXUP_LISP_OBJECT_RAW, we should stick a C pointer in
         the dump; otherwise, a Lisp_Object.  */
      if (SUBRP (arg))
        {
          dump_value = emacs_offset (XSUBR (arg));
          if (type == DUMP_FIXUP_LISP_OBJECT)
            dump_reloc_dump_to_emacs_lv (ctx, ctx->offset, XTYPE (arg));
          else
            dump_reloc_dump_to_emacs_ptr_raw (ctx, ctx->offset);
        }
      else if (dump_builtin_symbol_p (arg))
        {
          eassert (dump_object_self_representing_p (arg));
          /* These symbols are part of Emacs, so point there.  If we
             want a Lisp_Object, we're set.  If we want a raw pointer,
             we need to emit a relocation.  */
          if (type == DUMP_FIXUP_LISP_OBJECT)
            {
              do_write = false;
              dump_write (ctx, &arg, sizeof (arg));
            }
          else
            {
              dump_value = emacs_offset (XSYMBOL (arg));
              dump_reloc_dump_to_emacs_ptr_raw (ctx, ctx->offset);
            }
        }
      else
        {
          eassert (dump_object_emacs_ptr (arg) == NULL);
          dump_value = dump_recall_object (ctx, arg);
          if (dump_value <= 0)
            error ("fixup object not dumped");
          if (type == DUMP_FIXUP_LISP_OBJECT)
            dump_reloc_dump_to_dump_lv (ctx, ctx->offset, XTYPE (arg));
          else
            dump_reloc_dump_to_dump_ptr_raw (ctx, ctx->offset);
        }
      break;
    case DUMP_FIXUP_PTR_DUMP_RAW:
      /* Dump wants a raw pointer to something that's not a lisp
         object.  It knows the exact location it wants, so just
         believe it.  */
      dump_value = dump_off_from_lisp (arg);
      dump_reloc_dump_to_dump_ptr_raw (ctx, ctx->offset);
      break;
    default:
      emacs_abort ();
    }
  if (do_write)
    dump_write (ctx, &dump_value, sizeof (dump_value));
}

/* Return DUMP_OFFSET, making sure it is within the heap.  */
static dump_off
dump_check_dump_off (struct dump_context *ctx, dump_off dump_offset)
{
  eassert (dump_offset > 0);
  if (ctx)
    eassert (dump_offset < ctx->end_heap);
  return dump_offset;
}

static void
dump_check_emacs_off (dump_off emacs_off)
{
  eassert (labs (emacs_off) <= 30*1024*1024);
}

static void
dump_emit_dump_reloc (struct dump_context *ctx, Lisp_Object lreloc)
{
  struct dump_reloc reloc;
  dump_object_start (ctx, 1, &reloc, sizeof (reloc));
  dump_reloc_set_type (
    &reloc,
    (enum dump_reloc_type) XFASTINT (dump_pop (&lreloc)));
  eassert (reloc.type <= RELOC_DUMP_TO_EMACS_LV + Lisp_Float);
  dump_reloc_set_offset (&reloc, dump_off_from_lisp (dump_pop (&lreloc)));
  if (dump_reloc_get_offset (reloc) < ctx->header.discardable_start)
    ctx->number_hot_relocations += 1;
  else
    ctx->number_discardable_relocations += 1;

  dump_check_dump_off (ctx, dump_reloc_get_offset (reloc));
  eassert (NILP (lreloc));
  dump_object_finish (ctx, &reloc, sizeof (reloc));
}

static struct emacs_reloc
decode_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
{
  struct emacs_reloc reloc;
  memset (&reloc, 0, sizeof (reloc));
  ALLOW_IMPLICIT_CONVERSION;
  int type = XFASTINT (dump_pop (&lreloc));
  DISALLOW_IMPLICIT_CONVERSION;
  reloc.emacs_offset = dump_off_from_lisp (dump_pop (&lreloc));
  dump_check_emacs_off (reloc.emacs_offset);
  switch (type)
    {
    case RELOC_EMACS_COPY_FROM_DUMP:
      {
        emacs_reloc_set_type (&reloc, type);
        reloc.u.dump_offset = dump_off_from_lisp (dump_pop (&lreloc));
        dump_check_dump_off (ctx, reloc.u.dump_offset);
        dump_off length = dump_off_from_lisp (dump_pop (&lreloc));
        ALLOW_IMPLICIT_CONVERSION;
        reloc.length = length;
        DISALLOW_IMPLICIT_CONVERSION;
        if (reloc.length != length)
          error ("relocation copy length too large");
      }
      break;
    case RELOC_EMACS_IMMEDIATE:
      {
        emacs_reloc_set_type (&reloc, type);
        intmax_t value = intmax_t_from_lisp (dump_pop (&lreloc));
        dump_off size = dump_off_from_lisp (dump_pop (&lreloc));
        reloc.u.immediate = value;
        ALLOW_IMPLICIT_CONVERSION;
        reloc.length = size;
        DISALLOW_IMPLICIT_CONVERSION;
        eassert (reloc.length == size);
      }
      break;
    default:
      {
        eassert (RELOC_EMACS_DUMP_LV <= type);
        eassert (type <= RELOC_EMACS_DUMP_LV + Lisp_Float);
        emacs_reloc_set_type (&reloc, RELOC_EMACS_DUMP_LV);
        ALLOW_IMPLICIT_CONVERSION;
        reloc.length = type - RELOC_EMACS_DUMP_LV;
        DISALLOW_IMPLICIT_CONVERSION;
        eassert (reloc.length == type - RELOC_EMACS_DUMP_LV);
        Lisp_Object target_value = dump_pop (&lreloc);
        /* If the object is self-representing,
           dump_emacs_reloc_to_dump_lv didn't do its job.
           dump_emacs_reloc_to_dump_lv should have added a
           RELOC_EMACS_IMMEDIATE relocation instead.  */
        eassert (!dump_object_self_representing_p (target_value));
        reloc.u.dump_offset = dump_recall_object (ctx, target_value);
        if (reloc.u.dump_offset <= 0)
          {
            Lisp_Object repr = Fprin1_to_string (target_value, Qnil);
            error ("relocation target was not dumped: %s", SDATA (repr));
          }
        dump_check_dump_off (ctx, reloc.u.dump_offset);
      }
      break;
    case RELOC_EMACS_EMACS_PTR_RAW:
      emacs_reloc_set_type (&reloc, type);
      reloc.u.emacs_offset2 = dump_off_from_lisp (dump_pop (&lreloc));
      dump_check_emacs_off (reloc.u.emacs_offset2);
      break;
    case RELOC_EMACS_DUMP_PTR_RAW:
      emacs_reloc_set_type (&reloc, type);
      reloc.u.dump_offset = dump_off_from_lisp (dump_pop (&lreloc));
      dump_check_dump_off (ctx, reloc.u.dump_offset);
      break;
    }

  eassert (NILP (lreloc));
  return reloc;
}

static void
dump_emit_emacs_reloc (struct dump_context *ctx, Lisp_Object lreloc)
{
  struct emacs_reloc reloc;
  dump_object_start (ctx, 1, &reloc, sizeof (reloc));
  reloc = decode_emacs_reloc (ctx, lreloc);
  dump_object_finish (ctx, &reloc, sizeof (reloc));
}

static Lisp_Object
dump_merge_emacs_relocs (Lisp_Object lreloc_a, Lisp_Object lreloc_b)
{
  /* Combine copy relocations together if they're copying from
     adjacent chunks to adjacent chunks.  */

  if (XFASTINT (XCAR (lreloc_a)) != RELOC_EMACS_COPY_FROM_DUMP ||
      XFASTINT (XCAR (lreloc_b)) != RELOC_EMACS_COPY_FROM_DUMP)
    return Qnil;

  struct emacs_reloc reloc_a = decode_emacs_reloc (NULL, lreloc_a);
  struct emacs_reloc reloc_b = decode_emacs_reloc (NULL, lreloc_b);

  eassert (reloc_a.type == RELOC_EMACS_COPY_FROM_DUMP);
  eassert (reloc_b.type == RELOC_EMACS_COPY_FROM_DUMP);

  if (reloc_a.emacs_offset + reloc_a.length != reloc_b.emacs_offset)
    return Qnil;

  if (reloc_a.u.dump_offset + reloc_a.length != reloc_b.u.dump_offset)
    return Qnil;

  dump_off new_length = reloc_a.length + reloc_b.length;
  ALLOW_IMPLICIT_CONVERSION;
  reloc_a.length = new_length;
  DISALLOW_IMPLICIT_CONVERSION;
  if (reloc_a.length != new_length)
    return Qnil; /* Overflow */

  return list4 (make_number (RELOC_EMACS_COPY_FROM_DUMP),
                dump_off_to_lisp (reloc_a.emacs_offset),
                dump_off_to_lisp (reloc_a.u.dump_offset),
                dump_off_to_lisp (reloc_a.length));
}

static void
drain_reloc_list (struct dump_context *ctx,
                  void (*handler)(struct dump_context *, Lisp_Object),
                  Lisp_Object (*merger)(Lisp_Object a, Lisp_Object b),
                  Lisp_Object *reloc_list,
                  struct dump_table_locator *out_locator)
{
  Lisp_Object relocs = Fsort (Fnreverse (*reloc_list),
                              Qdump_emacs_portable__sort_predicate);
  *reloc_list = Qnil;
  dump_align_output (ctx, sizeof (dump_off));
  struct dump_table_locator locator;
  memset (&locator, 0, sizeof (locator));
  locator.offset = ctx->offset;
  for (; !NILP (relocs); locator.nr_entries += 1)
    {
      Lisp_Object reloc = dump_pop (&relocs);
      Lisp_Object merged;
      while (merger != NULL &&
             !NILP (relocs) &&
             ((merged = merger (reloc, XCAR (relocs))), !NILP (merged)))
        {
          reloc = merged;
          relocs = XCDR (relocs);
        }
      handler (ctx, reloc);
    }
  *out_locator = locator;
}

static void
dump_do_fixups (struct dump_context *ctx)
{
  dump_off saved_offset = ctx->offset;
  Lisp_Object fixups = Fsort (Fnreverse (ctx->fixups),
                              Qdump_emacs_portable__sort_predicate);
  ctx->fixups = Qnil;
  while (!NILP (fixups))
    dump_do_fixup (ctx, dump_pop (&fixups));
  dump_seek (ctx, saved_offset);
}

DEFUN ("dump-emacs-portable",
       Fdump_emacs_portable, Sdump_emacs_portable,
       1, 2, 0,
       doc: /* Dump current state of Emacs into dump file FILENAME.
If TRACK-REFERRERS is non-nil, keep additional debugging information
that can help track down the provenance of unsupported object
types.  */)
     (Lisp_Object filename, Lisp_Object track_referrers)
{
  eassert (initialized);

  if (will_dump_with_unexec_p ())
    error ("This Emacs instance was started under the assumption "
           "that it would be dumped with unexec, not the portable "
           "dumper.  Dumping with the portable dumper may produce "
           "unexpected results.");

  if (!main_thread_p (current_thread))
    error ("Function can be called only on main thread");

  /* Clear out any detritus in memory.  */
  do {
    number_finalizers_run = 0;
    Fgarbage_collect ();
  } while (number_finalizers_run);

  ptrdiff_t count = SPECPDL_INDEX ();

  /* Bind `command-line-processed' to nil before dumping,
     so that the dumped Emacs will process its command line
     and set up to work with X windows if appropriate.  */
  Lisp_Object symbol = intern ("command-line-processed");
  specbind (symbol, Qnil);

  CHECK_STRING (filename);
  filename = Fexpand_file_name (filename, Qnil);
  filename = ENCODE_FILE (filename);

  struct dump_context ctx_buf;
  struct dump_context *ctx = &ctx_buf;
  memset (ctx, 0, sizeof (*ctx));
  ctx->fd = -1;

  ctx->objects_dumped = make_eq_hash_table ();
  dump_queue_init (&ctx->dump_queue);
  ctx->deferred_hash_tables = Qnil;
  ctx->deferred_symbols = Qnil;
  ctx->fixups = Qnil;
  ctx->symbol_aux = Qnil;
  ctx->copied_queue = Qnil;
  ctx->cold_queue = Qnil;
  ctx->dump_relocs = Qnil;
  ctx->object_starts = Qnil;
  ctx->emacs_relocs = Qnil;

  /* Ordinarily, dump_object should remember where it saw objects and
     actually write the object contents to the dump file.  In special
     circumstances below, we temporarily change this default
     behavior.  */
  ctx->flags.dump_object_contents = true;
  ctx->flags.dump_object_starts = true;

  /* We want to consolidate certain object types that we know are very likely
     to be modified.  */
  ctx->flags.defer_hash_tables = true;
  // ctx->flags.defer_symbols = true;

  ctx->current_referrer = Qnil;
  if (!NILP (track_referrers))
    ctx->referrers = make_eq_hash_table ();

  ctx->dump_filename = filename;

  record_unwind_protect_ptr (dump_unwind_cleanup, ctx);
  block_input ();

#ifdef REL_ALLOC
  r_alloc_inhibit_buffer_relocation (1);
  ctx->blocked_ralloc = true;
#endif

  ctx->old_purify_flag = Vpurify_flag;
  Vpurify_flag = Qnil;

  /* Make sure various weird things are less likely to happen.  */
  ctx->old_post_gc_hook = Vpost_gc_hook;
  Vpost_gc_hook = Qnil;

  ctx->fd = emacs_open (SSDATA (filename),
                        O_RDWR | O_TRUNC | O_CREAT, 0666);
  if (ctx->fd < 0)
    report_file_error ("Opening dump output", filename);
  verify (sizeof (ctx->header.magic) == sizeof (dump_magic));
  memcpy (&ctx->header.magic, dump_magic, sizeof (dump_magic));
  ctx->header.magic[0] = '!'; /* Note that dump is incomplete.  */

  verify (sizeof (fingerprint) == sizeof (ctx->header.fingerprint));
  memcpy (ctx->header.fingerprint, fingerprint, sizeof (fingerprint));

  const dump_off header_start = ctx->offset;
  dump_fingerprint ("dumping fingerprint", ctx->header.fingerprint);
  dump_write (ctx, &ctx->header, sizeof (ctx->header));
  const dump_off header_end = ctx->offset;

  const dump_off hot_start = ctx->offset;
  /* Start the dump process by processing the static roots and
     queuing up the objects to which they refer.   */
  dump_roots (ctx);

  dump_charset_table (ctx);
  dump_finalizer_list_head_ptr (ctx, &finalizers.prev);
  dump_finalizer_list_head_ptr (ctx, &finalizers.next);
  dump_finalizer_list_head_ptr (ctx, &doomed_finalizers.prev);
  dump_finalizer_list_head_ptr (ctx, &doomed_finalizers.next);
  dump_user_remembered_data_hot (ctx);

  /* We've already remembered all the objects to which GC roots point,
     but we have to manually save the list of GC roots itself.  */
  dump_metadata_for_pdumper (ctx);
  for (int i = 0; i < staticidx; ++i)
    dump_emacs_reloc_to_emacs_ptr_raw (ctx, &staticvec[i], staticvec[i]);
  dump_emacs_reloc_immediate_int (ctx, &staticidx, staticidx);

  /* Dump until while we keep finding objects to dump.  We add new
     objects to the queue by side effect during dumping.  */
  while (!dump_queue_empty_p (&ctx->dump_queue))
    dump_object (ctx, dump_queue_dequeue (&ctx->dump_queue, ctx->offset));
  eassert (dump_queue_empty_p (&ctx->dump_queue));

  /* We may have deferred some objects.  */
  ctx->flags.defer_hash_tables = false;
  ctx->deferred_hash_tables = Fnreverse (ctx->deferred_hash_tables);
  while (!NILP (ctx->deferred_hash_tables))
    dump_object (ctx, dump_pop (&ctx->deferred_hash_tables));
  while (!dump_queue_empty_p (&ctx->dump_queue))
    dump_object (ctx, dump_queue_dequeue (&ctx->dump_queue, ctx->offset));
  eassert (dump_queue_empty_p (&ctx->dump_queue));

  /* We may have deferred some symbols.  */
  ctx->flags.defer_symbols = false;
  ctx->deferred_symbols = Fnreverse (ctx->deferred_symbols);
  while (!NILP (ctx->deferred_symbols))
    dump_object (ctx, dump_pop (&ctx->deferred_symbols));
  while (!dump_queue_empty_p (&ctx->dump_queue))
    dump_object (ctx, dump_queue_dequeue (&ctx->dump_queue, ctx->offset));
  eassert (dump_queue_empty_p (&ctx->dump_queue));

  dump_sort_copied_objects (ctx);
  ctx->symbol_aux = make_eq_hash_table ();
  dump_hot_parts_of_discardable_objects (ctx);
  const dump_off hot_end = ctx->offset;

  /* Emacs, after initial dump loading, can forget about the portion
     of the dump that runs from here to the start of the cold section.
     This section consists of objects that need to be memcpy()ed into
     the Emacs data section instead of just used directly.  */
  ctx->header.discardable_start = ctx->offset;
  ctx->flags.dump_object_starts = false;

  dump_copied_objects (ctx);
  eassert (dump_queue_empty_p (&ctx->dump_queue));
  eassert (NILP (ctx->copied_queue));
  dump_off discardable_end = ctx->offset;
  dump_align_output (ctx, dump_get_page_size ());
  ctx->header.cold_start = ctx->offset;

  /* Resume recording object starts, since the cold section will stick
     around.  */
  ctx->flags.dump_object_starts = true;

  /* Start the cold section.  This section contains bytes that should
     never change and so can be direct-mapped from the dump without
     special processing.  */
  dump_cold_data (ctx);
   /* dump_user_remembered_data_cold needs to be after dump_cold_data
      in case dump_cold_data dumps a lisp object to which C code
      points.  dump_user_remembered_data_cold assumes that all lisp
      objects have been dumped.  */
  dump_user_remembered_data_cold (ctx);

  /* After this point, the dump file contains no data that can be part
     of the Lisp heap.  */
  ctx->end_heap = ctx->offset;

  /* Make remembered modifications to the dump file itself.  */
  dump_do_fixups (ctx);

  /* Emit instructions for Emacs to execute when loading the dump.
     Note that this relocation information ends up in the cold section
     of the dump.  */
  drain_reloc_list (
    ctx, dump_emit_dump_reloc, NULL,
    &ctx->dump_relocs,
    &ctx->header.dump_relocs);
  unsigned number_hot_relocations = ctx->number_hot_relocations;
  ctx->number_hot_relocations = 0;
  unsigned number_discardable_relocations = ctx->number_discardable_relocations;
  ctx->number_discardable_relocations = 0;
  drain_reloc_list (
    ctx, dump_emit_dump_reloc, NULL,
    &ctx->object_starts,
    &ctx->header.object_starts);
  drain_reloc_list (
    ctx, dump_emit_emacs_reloc, dump_merge_emacs_relocs,
    &ctx->emacs_relocs,
    &ctx->header.emacs_relocs);

  const dump_off cold_end = ctx->offset;

  eassert (dump_queue_empty_p (&ctx->dump_queue));
  eassert (NILP (ctx->fixups));
  eassert (NILP (ctx->dump_relocs));
  eassert (NILP (ctx->emacs_relocs));

  /* Dump is complete.  Go back to the header and write the magic
     indicating that the dump is complete and can be loaded.  */
  ctx->header.magic[0] = dump_magic[0];
  dump_seek (ctx, 0);
  dump_write (ctx, &ctx->header, sizeof (ctx->header));

  fprintf (stderr, "Dump complete\n");
  fprintf (stderr,
           "Byte counts: header=%lu hot=%lu discardable=%lu cold=%lu\n",
           (unsigned long) (header_end - header_start),
           (unsigned long) (hot_end - hot_start),
           (unsigned long) (discardable_end - ctx->header.discardable_start),
           (unsigned long) (cold_end - ctx->header.cold_start));
  fprintf (stderr, "Reloc counts: hot=%u discardable=%u\n",
           number_hot_relocations,
           number_discardable_relocations);

  return unbind_to (count, Qnil);


}

DEFUN ("dump-emacs-portable--sort-predicate",
       Fdump_emacs_portable__sort_predicate,
       Sdump_emacs_portable__sort_predicate,
       2, 2, 0,
       doc: /* Internal relocation sorting function.  */)
     (Lisp_Object a, Lisp_Object b)
{
  dump_off a_offset = dump_off_from_lisp (XCAR (XCDR (a)));
  dump_off b_offset = dump_off_from_lisp (XCAR (XCDR (b)));
  return a_offset < b_offset ? Qt : Qnil;
}

DEFUN ("dump-emacs-portable--sort-predicate-copied",
       Fdump_emacs_portable__sort_predicate_copied,
       Sdump_emacs_portable__sort_predicate_copied,
       2, 2, 0,
       doc: /* Internal relocation sorting function.  */)
     (Lisp_Object a, Lisp_Object b)
{
  eassert (dump_object_emacs_ptr (a));
  eassert (dump_object_emacs_ptr (b));
  return dump_object_emacs_ptr (a) < dump_object_emacs_ptr (b) ? Qt : Qnil;
}

void
pdumper_do_now_and_after_load_impl (pdumper_hook hook)
{
  if (nr_dump_hooks == ARRAYELTS (dump_hooks))
    fatal ("out of dump hooks: make dump_hooks[] bigger");
  dump_hooks[nr_dump_hooks++] = hook;
  hook ();
}

static void
pdumper_remember_user_data_1 (void *mem, int nbytes)
{
  if (nr_remembered_data == ARRAYELTS (remembered_data))
    fatal ("out of remembered data slots: make remembered_data[] bigger");
  remembered_data[nr_remembered_data].mem = mem;
  remembered_data[nr_remembered_data].sz = nbytes;
  nr_remembered_data += 1;
}

void
pdumper_remember_scalar_impl (void *mem, ptrdiff_t nbytes)
{
  eassert (0 <= nbytes && nbytes <= INT_MAX);
  if (nbytes > 0)
    pdumper_remember_user_data_1 (mem, (int) nbytes);
}

void
pdumper_remember_lv_ptr_raw_impl (void* ptr, enum Lisp_Type type)
{
  pdumper_remember_user_data_1 (ptr, -type);
}

\f
/* Dump runtime */
enum dump_memory_protection {
  DUMP_MEMORY_ACCESS_NONE = 1,
  DUMP_MEMORY_ACCESS_READ = 2,
  DUMP_MEMORY_ACCESS_READWRITE = 3,
};

static void *
dump_anonymous_allocate_w32 (void *base,
                             size_t size,
                             enum dump_memory_protection protection)
{
#if VM_SUPPORTED != VM_MS_WINDOWS
  (void) base;
  (void) size;
  (void) protection;
  emacs_abort ();
#else
  void *ret;
  DWORD mem_type;
  DWORD mem_prot;

  switch (protection)
    {
    case DUMP_MEMORY_ACCESS_NONE:
      mem_type = MEM_RESERVE;
      mem_prot = PAGE_NOACCESS;
      break;
    case DUMP_MEMORY_ACCESS_READ:
      mem_type = MEM_COMMIT;
      mem_prot = PAGE_READONLY;
      break;
    case DUMP_MEMORY_ACCESS_READWRITE:
      mem_type = MEM_COMMIT;
      mem_prot = PAGE_READWRITE;
      break;
    default:
      emacs_abort ();
    }

  ret = VirtualAlloc (base, size, mem_type, mem_prot);
  if (ret == NULL)
    errno = (base && GetLastError () == ERROR_INVALID_ADDRESS)
      ? EBUSY
      : EPERM;
  return ret;
#endif
}

static void *
dump_anonymous_allocate_posix (void *base,
                               size_t size,
                               enum dump_memory_protection protection)
{
#if VM_SUPPORTED != VM_POSIX
  (void) base;
  (void) size;
  (void) protection;
  emacs_abort ();
#else
  void *ret;
  int mem_prot;

  switch (protection)
    {
    case DUMP_MEMORY_ACCESS_NONE:
      mem_prot = PROT_NONE;
      break;
    case DUMP_MEMORY_ACCESS_READ:
      mem_prot = PROT_READ;
      break;
    case DUMP_MEMORY_ACCESS_READWRITE:
      mem_prot = PROT_READ | PROT_WRITE;
      break;
    default:
      emacs_abort ();
    }

  int mem_flags = MAP_PRIVATE | MAP_ANONYMOUS;
  if (mem_prot != PROT_NONE)
    mem_flags |= MAP_POPULATE;
  if (base)
    mem_flags |= MAP_FIXED;

  bool retry;
  do
    {
      retry = false;
      ret = mmap (base, size, mem_prot, mem_flags, -1, 0);
      if (ret == MAP_FAILED &&
          errno == EINVAL &&
          (mem_flags & MAP_POPULATE))
        {
          /* This system didn't understand MAP_POPULATE, so try
             again without it.  */
          mem_flags &= ~MAP_POPULATE;
          retry = true;
        }
    }
  while (retry);

  if (ret == MAP_FAILED)
    ret = NULL;
  return ret;
#endif
}

/* Perform anonymous memory allocation.  */
static void *
dump_anonymous_allocate (void *base,
                         const size_t size,
                         enum dump_memory_protection protection)
{
  void *ret = NULL;
  if (VM_SUPPORTED == VM_MS_WINDOWS)
    ret = dump_anonymous_allocate_w32 (base, size, protection);
  else if (VM_SUPPORTED == VM_POSIX)
    ret = dump_anonymous_allocate_posix (base, size, protection);
  else
    errno = ENOSYS;
  return ret;
}

/* Undo the effect of dump_reserve_address_space().  */
static void
dump_anonymous_release (void *addr, size_t size)
{
  eassert (size >= 0);
#if VM_SUPPORTED == VM_MS_WINDOWS
  (void) size;
  if (!VirtualFree (addr, 0, MEM_RELEASE))
    emacs_abort ();
#elif VM_SUPPORTED == VM_POSIX
  if (munmap (addr, size) < 0)
    emacs_abort ();
#else
  (void) addr;
  (void) size;
  emacs_abort ();
#endif
}

static void *
dump_map_file_w32 (
  void *base,
  int fd,
  off_t offset,
  size_t size,
  enum dump_memory_protection protection)
{
#if VM_SUPPORTED != VM_MS_WINDOWS
  (void) base;
  (void) fd;
  (void) offset;
  (void) size;
  (void) protection;
  emacs_abort ();
#else
  void *ret = NULL;
  HANDLE section = NULL;
  HANDLE file;

  uint64_t full_offset = offset;
  uint32_t offset_high = (uint32_t) (full_offset >> 32);
  uint32_t offset_low = (uint32_t) (full_offset & 0xffffffff);

  int error;
  DWORD map_access;

  file = (HANDLE) _get_osfhandle (fd);
  if (file == INVALID_HANDLE_VALUE)
    goto out;

  section = CreateFileMapping (
    file,
    /*lpAttributes=*/NULL,
    PAGE_READONLY,
    /*dwMaximumSizeHigh=*/0,
    /*dwMaximumSizeLow=*/0,
    /*lpName=*/NULL);
  if (!section)
    {
      errno = EINVAL;
      goto out;
    }

  switch (protection)
    {
    case DUMP_MEMORY_ACCESS_NONE:
    case DUMP_MEMORY_ACCESS_READ:
      map_access = FILE_MAP_READ;
      break;
    case DUMP_MEMORY_ACCESS_READWRITE:
      map_access = FILE_MAP_COPY;
      break;
    default:
      emacs_abort ();
    }

  ret = MapViewOfFileEx (section,
                         map_access,
                         offset_high,
                         offset_low,
                         size,
                         base);

  error = GetLastError ();
  if (ret == NULL)
    errno = (error == ERROR_INVALID_ADDRESS ? EBUSY : EPERM);
 out:
  if (section && !CloseHandle (section))
    emacs_abort ();
  return ret;
#endif
}

static void *
dump_map_file_posix (
  void *base,
  int fd,
  off_t offset,
  size_t size,
  enum dump_memory_protection protection)
{
#if VM_SUPPORTED != VM_POSIX
  (void) base;
  (void) fd;
  (void) offset;
  (void) size;
  (void) protection;
  emacs_abort ();
#else
  void *ret;
  int mem_prot;
  int mem_flags;

  switch (protection)
    {
    case DUMP_MEMORY_ACCESS_NONE:
      mem_prot = PROT_NONE;
      mem_flags = MAP_SHARED;
      break;
    case DUMP_MEMORY_ACCESS_READ:
      mem_prot = PROT_READ;
      mem_flags = MAP_SHARED;
      break;
    case DUMP_MEMORY_ACCESS_READWRITE:
      mem_prot = PROT_READ | PROT_WRITE;
      mem_flags = MAP_PRIVATE;
      break;
    default:
      emacs_abort ();
    }

  if (base)
    mem_flags |= MAP_FIXED;

  ret = mmap (base, size, mem_prot, mem_flags, fd, offset);
  if (ret == MAP_FAILED)
    ret = NULL;
  return ret;
#endif
}

/* Map a file into memory.  */
static void *
dump_map_file (
  void *base,
  int fd,
  off_t offset,
  size_t size,
  enum dump_memory_protection protection)
{
  void *ret = NULL;
  if (VM_SUPPORTED == VM_MS_WINDOWS)
    ret = dump_map_file_w32 (base, fd, offset, size, protection);
  else if (VM_SUPPORTED == VM_POSIX)
    ret = dump_map_file_posix (base, fd, offset, size, protection);
  else
    errno = ENOSYS;
  return ret;
}

/* Remove a virtual memory mapping.

   On failure, abort Emacs.  For maximum platform compatibility, ADDR
   and SIZE must match the mapping exactly.  */
static void
dump_unmap_file (void *addr, size_t size)
{
  eassert (size >= 0);
#if !VM_SUPPORTED
  (void) addr;
  (void) size;
  emacs_abort ();
#elif defined (WINDOWSNT)
  (void) size;
  if (!UnmapViewOfFile (addr))
    emacs_abort ();
#else
  if (munmap (addr, size) < 0)
    emacs_abort ();
#endif
}

struct dump_memory_map_spec
{
  int fd;  /* File to map; anon zero if negative.  */
  size_t size;  /* Number of bytes to map.  */
  off_t offset;  /* Offset within fd.  */
  enum dump_memory_protection protection;
};

struct dump_memory_map {
  struct dump_memory_map_spec spec;
  void *mapping;  /* Actual mapped memory.  */
  void (*release)(struct dump_memory_map *);
  void *private;
};

/* Mark the pages as unneeded, potentially zeroing them, without
   releasing the address space reservation.  */
static void
dump_discard_mem (void *mem, size_t size)
{
#if VM_SUPPORTED == VM_MS_WINDOWS
      /* Discard COWed pages.  */
      (void) VirtualFree (mem, size, MEM_DECOMMIT);
      /* Release the commit charge for the mapping.  */
      (void) VirtualProtect (mem, size, PAGE_NOACCESS, NULL);
#elif VM_SUPPORTED == VM_POSIX
# ifdef HAVE_POSIX_MADVISE
      /* Discard COWed pages.  */
      (void) posix_madvise (mem, size, POSIX_MADV_DONTNEED);
# endif
      /* Release the commit charge for the mapping.  */
      (void) mprotect (mem, size, PROT_NONE);
#endif
}

static void
dump_mmap_discard_contents (struct dump_memory_map *map)
{
  if (map->mapping)
    dump_discard_mem (map->mapping, map->spec.size);
}

static void
dump_mmap_reset (struct dump_memory_map *map)
{
  map->mapping = NULL;
  map->release = NULL;
  map->private = NULL;
}

static void
dump_mmap_release (struct dump_memory_map *map)
{
  if (map->release)
    map->release (map);
  dump_mmap_reset (map);
}

/* Allows heap-allocated dump_mmap to "free" maps individually.  */
struct dump_memory_map_heap_control_block {
  int refcount;
  void *mem;
};

static void
dump_mm_heap_cb_release (struct dump_memory_map_heap_control_block *cb)
{
  eassert (cb->refcount > 0);
  if (--cb->refcount == 0)
    {
      free (cb->mem);
      free (cb);
    }
}

static void
dump_mmap_release_heap (struct dump_memory_map *map)
{
  struct dump_memory_map_heap_control_block *cb = map->private;
  dump_mm_heap_cb_release (cb);
}

/* Implement dump_mmap using malloc and read.  */
static bool
dump_mmap_contiguous_heap (
  struct dump_memory_map *maps,
  int nr_maps,
  size_t total_size)
{
  bool ret = false;
  struct dump_memory_map_heap_control_block *cb = calloc (1, sizeof (*cb));
  char *mem;
  if (!cb)
    goto out;
  cb->refcount = 1;
  cb->mem = malloc (total_size);
  if (!cb->mem)
    goto out;
  mem = cb->mem;
  for (int i = 0; i < nr_maps; ++i)
    {
      struct dump_memory_map *map = &maps[i];
      const struct dump_memory_map_spec spec = map->spec;
      if (!spec.size)
        continue;
      map->mapping = mem;
      mem += spec.size;
      map->release = dump_mmap_release_heap;
      map->private = cb;
      cb->refcount += 1;
      if (spec.fd < 0)
        memset (map->mapping, 0, spec.size);
      else
        {
          if (lseek (spec.fd, spec.offset, SEEK_SET) < 0)
            goto out;
          ssize_t nb = dump_read_all (spec.fd,
                                      map->mapping,
                                      spec.size);
          if (nb >= 0 && nb != spec.size)
            errno = EIO;
          if (nb != spec.size)
            goto out;
        }
    }

  ret = true;
 out:
  dump_mm_heap_cb_release (cb);
  if (!ret)
    for (int i = 0; i < nr_maps; ++i)
      dump_mmap_release (&maps[i]);
  return ret;
}

static void
dump_mmap_release_vm (struct dump_memory_map *map)
{
  if (map->spec.fd < 0)
    dump_anonymous_release (map->mapping, map->spec.size);
  else
    dump_unmap_file (map->mapping, map->spec.size);
}

static bool
dump_mmap_contiguous_vm (
  struct dump_memory_map *maps,
  int nr_maps,
  size_t total_size)
{
  bool ret = false;
  void *resv = NULL;
  bool retry = false;

  do
    {
      if (retry)
        {
          eassert (VM_SUPPORTED == VM_MS_WINDOWS);
          retry = false;
          for (int i = 0; i < nr_maps; ++i)
            dump_mmap_release (&maps[i]);
        }

      eassert (resv == NULL);
      resv = dump_anonymous_allocate (NULL,
                                      total_size,
                                      DUMP_MEMORY_ACCESS_NONE);
      if (!resv)
        goto out;

      char *mem = resv;

      if (VM_SUPPORTED == VM_MS_WINDOWS)
        {
          /* Windows lacks atomic mapping replace; need to release the
             reservation so we can allocate within it.  Will retry the
             loop if someone squats on our address space before we can
             finish allocation.  On POSIX systems, we leave the
             reservation around for atomicity.  */
          dump_anonymous_release (resv, total_size);
          resv = NULL;
        }

      for (int i = 0; i < nr_maps; ++i)
        {
          struct dump_memory_map *map = &maps[i];
          const struct dump_memory_map_spec spec = map->spec;
          if (!spec.size)
            continue;

          if (spec.fd < 0)
            map->mapping = dump_anonymous_allocate (
              mem, spec.size, spec.protection);
          else
            map->mapping = dump_map_file (
              mem, spec.fd, spec.offset, spec.size, spec.protection);
          mem += spec.size;
          if (VM_SUPPORTED == VM_MS_WINDOWS &&
              map->mapping == NULL &&
              errno == EBUSY)
            {
              retry = true;
              continue;
            }
          if (map->mapping == NULL)
            goto out;
          map->release = dump_mmap_release_vm;
        }
    }
  while (retry);

  ret = true;
  resv = NULL;
 out:
  if (resv)
    dump_anonymous_release (resv, total_size);
  if (!ret)
    {
      for (int i = 0; i < nr_maps; ++i)
	{
	  if (VM_SUPPORTED == VM_MS_WINDOWS)
	    dump_mmap_reset (&maps[i]);
	  else
	    dump_mmap_release (&maps[i]);
	}
    }
  return ret;
}

/* Map a range of addresses into a chunk of contiguous memory.

   Each dump_memory_map structure describes how to fill the
   corresponding range of memory. On input, all members except MAPPING
   are valid. On output, MAPPING contains the location of the given
   chunk of memory. The MAPPING for MAPS[N] is MAPS[N-1].mapping +
   MAPS[N-1].size.

   Each mapping SIZE must be a multiple of the system page size except
   for the last mapping.

   Return true on success or false on failure with errno set.  */
static bool
dump_mmap_contiguous (
  struct dump_memory_map *maps,
  int nr_maps)
{
  if (!nr_maps)
    return true;

  size_t total_size = 0;
  int worst_case_page_size = dump_get_page_size ();

  for (int i = 0; i < nr_maps; ++i)
    {
      eassert (maps[i].mapping == NULL);
      eassert (maps[i].release == NULL);
      eassert (maps[i].private == NULL);
      if (i != nr_maps - 1)
        eassert (maps[i].spec.size % worst_case_page_size == 0);
      total_size += maps[i].spec.size;
    }

  return (VM_SUPPORTED ?
          dump_mmap_contiguous_vm :
          dump_mmap_contiguous_heap)
    (maps, nr_maps, total_size);
}

typedef uint_fast32_t dump_bitset_word;

struct dump_bitset {
  dump_bitset_word *restrict bits;
  ptrdiff_t number_words;
};

static bool
dump_bitset_init (struct dump_bitset *bitset, size_t number_bits)
{
  memset (bitset, 0, sizeof (*bitset));
  int xword_size = sizeof (bitset->bits[0]);
  int bits_per_word = xword_size * CHAR_BIT;
  ptrdiff_t words_needed = DIVIDE_ROUND_UP (number_bits, bits_per_word);
  bitset->number_words = words_needed;
  bitset->bits = calloc (words_needed, xword_size);
  return bitset->bits != NULL;
}

static void
dump_bitset_destroy (struct dump_bitset *bitset)
{
  free (bitset->bits);
}

static dump_bitset_word *
dump_bitset__bit_slot (const struct dump_bitset *bitset,
                       size_t bit_number)
{
  int xword_size = sizeof (bitset->bits[0]);
  int bits_per_word = xword_size * CHAR_BIT;
  ptrdiff_t word_number = bit_number / bits_per_word;
  eassert (word_number < bitset->number_words);
  return &bitset->bits[word_number];
}

static bool
dump_bitset_bit_set_p (const struct dump_bitset *bitset,
                       size_t bit_number)
{
  unsigned xword_size = sizeof (bitset->bits[0]);
  unsigned bits_per_word = xword_size * CHAR_BIT;
  dump_bitset_word bit = 1;
  bit <<= bit_number % bits_per_word;
  return *dump_bitset__bit_slot (bitset, bit_number) & bit;
}

static void
dump_bitset__set_bit_value (struct dump_bitset *bitset,
                            size_t bit_number,
                            bool bit_is_set)
{
  int xword_size = sizeof (bitset->bits[0]);
  int bits_per_word = xword_size * CHAR_BIT;
  dump_bitset_word * slot = dump_bitset__bit_slot (bitset, bit_number);
  dump_bitset_word bit = 1;
  bit <<= bit_number % bits_per_word;
  if (bit_is_set)
    *slot = *slot | bit;
  else
    *slot = *slot & ~bit;
}

static void
dump_bitset_set_bit (struct dump_bitset *bitset, size_t bit_number)
{
  dump_bitset__set_bit_value (bitset, bit_number, true);
}

static void
dump_bitset_clear (struct dump_bitset *bitset)
{
  int xword_size = sizeof (bitset->bits[0]);
  memset (bitset->bits, 0, bitset->number_words * xword_size);
}

struct pdumper_loaded_dump_private
{
  /* Copy of the header we read from the dump.  */
  struct dump_header header;
  /* Mark bits for objects in the dump; used during GC.  */
  struct dump_bitset mark_bits;
};

struct pdumper_loaded_dump dump_public;
struct pdumper_loaded_dump_private dump_private;

/* Return a pointer to offset OFFSET within the dump, which begins at
   DUMP_BASE. DUMP_BASE must be equal to the current dump load
   location; it's passed as a parameter for efficiency.

   The returned pointer points to the primary memory image of the
   currently-loaded dump file.  The entire dump file is accessible
   using this function.  */
static void *
dump_ptr (intptr_t dump_base, dump_off offset)
{
  eassert (dump_base == dump_public.start);
  eassert (dump_public.start + offset < dump_public.end);
  return (char *)dump_public.start + offset;
}

/* Read a pointer-sized word of memory at OFFSET within the dump,
   which begins at DUMP_BASE. DUMP_BASE must be equal to the current
   dump load location; it's passed as a parameter for efficiency.  */
static uintptr_t
dump_read_word_from_dump (intptr_t dump_base, dump_off offset)
{
  uintptr_t value;
  /* The compiler optimizes this memcpy into a read.  */
  memcpy (&value, dump_ptr (dump_base, offset), sizeof (value));
  return value;
}

/* Write a word to the dump. DUMP_BASE and OFFSET are as for
   dump_read_word_from_dump; VALUE is the word to write at the given
   offset.  */
static void
dump_write_word_to_dump (intptr_t dump_base,
                         dump_off offset,
                         uintptr_t value)
{
  /* The compiler optimizes this memcpy into a write.  */
  memcpy (dump_ptr (dump_base, offset), &value, sizeof (value));
}

/* Write a Lisp_Object to the dump. DUMP_BASE and OFFSET are as for
   dump_read_word_from_dump; VALUE is the Lisp_Object to write at the
   given offset.  */
static void
dump_write_lv_to_dump (intptr_t dump_base,
                       dump_off offset,
                       Lisp_Object value)
{
  /* The compiler optimizes this memcpy into a write.  */
  memcpy (dump_ptr (dump_base, offset), &value, sizeof (value));
}

/* Search for a relocation given a relocation target.

   DUMP is the dump metadata structure.  TABLE is the relocation table
   to search.  KEY is the dump offset to find.  Return the relocation
   RELOC such that RELOC.offset is the smallest RELOC.offset that
   satisfies the constraint KEY <= RELOC.offset --- that is, return
   the first relocation at KEY or after KEY.  Return NULL if no such
   relocation exists.  */
static const struct dump_reloc *
dump_find_relocation (const struct dump_table_locator *const table,
                      const dump_off key)
{
  const struct dump_reloc *const relocs = dump_ptr (
    dump_public.start, table->offset);
  const struct dump_reloc *found = NULL;
  ptrdiff_t idx_left = 0;
  ptrdiff_t idx_right = table->nr_entries;

  eassert (key >= 0);

  while (idx_left < idx_right)
    {
      const ptrdiff_t idx_mid = idx_left + (idx_right - idx_left) / 2;
      const struct dump_reloc *mid = &relocs[idx_mid];
      if (key > dump_reloc_get_offset (*mid))
        idx_left = idx_mid + 1;
      else
        {
          found = mid;
          idx_right = idx_mid;
          if (idx_right <= idx_left ||
              key > dump_reloc_get_offset (relocs[idx_right - 1]))
            break;
        }
   }

  return found;
}

static bool
dump_loaded_p (void)
{
  return dump_public.start != 0;
}

bool
pdumper_cold_object_p_impl (const void *obj)
{
  eassert (pdumper_object_p (obj));
  eassert (pdumper_object_p_precise (obj));
  dump_off offset = ptrdiff_t_to_dump_off (
    (intptr_t) obj - dump_public.start);
  return offset >= dump_private.header.cold_start;
}

enum Lisp_Type
pdumper_find_object_type_impl (const void *obj)
{
  eassert (pdumper_object_p (obj));
  dump_off offset = ptrdiff_t_to_dump_off (
    (intptr_t) obj - dump_public.start);
  if (offset % GCALIGNMENT != 0)
    return PDUMPER_NO_OBJECT;
  const struct dump_reloc *reloc =
    dump_find_relocation (&dump_private.header.object_starts, offset);
  return (reloc != NULL && dump_reloc_get_offset (*reloc) == offset)
    ? (enum Lisp_Type) reloc->type
    : PDUMPER_NO_OBJECT;
}

bool
pdumper_marked_p_impl (const void *obj)
{
  eassert (pdumper_object_p (obj));
  ptrdiff_t offset = (intptr_t) obj - dump_public.start;
  eassert (offset % GCALIGNMENT == 0);
  eassert (offset < dump_private.header.cold_start);
  eassert (offset < dump_private.header.discardable_start);
  ptrdiff_t bitno = offset / GCALIGNMENT;
  return dump_bitset_bit_set_p (&dump_private.mark_bits, bitno);
}

void
pdumper_set_marked_impl (const void *obj)
{
  eassert (pdumper_object_p (obj));
  ptrdiff_t offset = (intptr_t) obj - dump_public.start;
  eassert (offset % GCALIGNMENT == 0);
  eassert (offset < dump_private.header.cold_start);
  eassert (offset < dump_private.header.discardable_start);
  ptrdiff_t bitno = offset / GCALIGNMENT;
  dump_bitset_set_bit (&dump_private.mark_bits, bitno);
}

void
pdumper_clear_marks_impl (void)
{
  dump_bitset_clear (&dump_private.mark_bits);
}

static ssize_t
dump_read_all (int fd, void *buf, size_t bytes_to_read)
{
  /* We don't want to use emacs_read, since that relies on the lisp
     world, and we're not in the lisp world yet.  */
  eassert (bytes_to_read <= SSIZE_MAX);
  size_t bytes_read = 0;
  while (bytes_read < bytes_to_read)
    {
      ssize_t chunk =
        read (fd, (char*) buf + bytes_read, bytes_to_read - bytes_read);
      if (chunk < 0)
        return chunk;
      if (chunk == 0)
        break;
      bytes_read += chunk;
    }

  return bytes_read;
}

static void *
emacs_ptr (const ptrdiff_t offset)
{
  // TODO: assert somehow that offset is actually inside Emacs
  return (void *) (emacs_basis () + offset);
}

/* Return the number of bytes written when we perform the given
   relocation.  */
static int
dump_reloc_size (const struct dump_reloc reloc)
{
  if (sizeof (Lisp_Object) == sizeof (void*))
    return sizeof (Lisp_Object);
  if (reloc.type == RELOC_DUMP_TO_EMACS_PTR_RAW ||
      reloc.type == RELOC_DUMP_TO_DUMP_PTR_RAW)
    return sizeof (void*);
  return sizeof (Lisp_Object);
}

static Lisp_Object
dump_make_lv_from_reloc (
  const intptr_t dump_base,
  const struct dump_reloc reloc)
{
  const dump_off reloc_offset = dump_reloc_get_offset (reloc);
  uintptr_t value = dump_read_word_from_dump (dump_base, reloc_offset);
  enum Lisp_Type lisp_type;

  if (RELOC_DUMP_TO_DUMP_LV <= reloc.type &&
      reloc.type < RELOC_DUMP_TO_EMACS_LV)
    {
      lisp_type = reloc.type - RELOC_DUMP_TO_DUMP_LV;
      value += dump_base;
    }
  else
    {
      eassert (RELOC_DUMP_TO_EMACS_LV <= reloc.type);
      eassert (reloc.type < RELOC_DUMP_TO_EMACS_LV + 8);
      lisp_type = reloc.type - RELOC_DUMP_TO_EMACS_LV;
      value += emacs_basis ();
    }

  eassert (lisp_type != Lisp_Int0 && lisp_type != Lisp_Int1);

  Lisp_Object lv;
  if (lisp_type == Lisp_Symbol)
    lv = make_lisp_symbol ((void *) value);
  else
    lv = make_lisp_ptr ((void *) value, lisp_type);

  return lv;
}

/* Actually apply a dump relocation.  */
static inline void
dump_do_dump_relocation (
  const intptr_t dump_base,
  const struct dump_reloc reloc)
{
  const dump_off reloc_offset = dump_reloc_get_offset (reloc);

  /* We should never generate a relocation in the cold section.  */
  eassert (reloc_offset < dump_private.header.cold_start);

  switch (reloc.type)
    {
    case RELOC_DUMP_TO_EMACS_PTR_RAW:
      {
        uintptr_t value = dump_read_word_from_dump (dump_base, reloc_offset);
        eassert (dump_reloc_size (reloc) == sizeof (value));
        value += emacs_basis ();
        dump_write_word_to_dump (dump_base, reloc_offset, value);
        break;
      }
    case RELOC_DUMP_TO_DUMP_PTR_RAW:
      {
        uintptr_t value = dump_read_word_from_dump (dump_base, reloc_offset);
        eassert (dump_reloc_size (reloc) == sizeof (value));
        value += dump_base;
        dump_write_word_to_dump (dump_base, reloc_offset, value);
        break;
      }
    default: /* Lisp_Object in the dump; precise type in reloc.type */
      {
        Lisp_Object lv = dump_make_lv_from_reloc (dump_base, reloc);
        eassert (dump_reloc_size (reloc) == sizeof (lv));
        dump_write_lv_to_dump (dump_base, reloc_offset, lv);
        break;
      }
    }
}

static void
dump_do_all_dump_relocations (
  const struct dump_header *const header,
  const intptr_t dump_base)
{
  struct dump_reloc *r = dump_ptr (dump_base, header->dump_relocs.offset);
  dump_off nr_entries = header->dump_relocs.nr_entries;
  for (dump_off i = 0; i < nr_entries; ++i)
    dump_do_dump_relocation (dump_base, r[i]);
}

static void
dump_do_emacs_relocation (
  const intptr_t dump_base,
  const struct emacs_reloc reloc)
{
  ptrdiff_t pval;
  Lisp_Object lv;

  switch (reloc.type)
    {
    case RELOC_EMACS_COPY_FROM_DUMP:
      eassume (reloc.length > 0);
      memcpy (emacs_ptr (reloc.emacs_offset),
              dump_ptr (dump_base, reloc.u.dump_offset),
              reloc.length);
      break;
    case RELOC_EMACS_IMMEDIATE:
      eassume (reloc.length > 0);
      eassume (reloc.length <= sizeof (reloc.u.immediate));
      memcpy (emacs_ptr (reloc.emacs_offset),
              &reloc.u.immediate,
              reloc.length);
      break;
    case RELOC_EMACS_DUMP_PTR_RAW:
      pval = reloc.u.dump_offset + dump_base;
      memcpy (emacs_ptr (reloc.emacs_offset), &pval, sizeof (pval));
      break;
    case RELOC_EMACS_EMACS_PTR_RAW:
      pval = reloc.u.emacs_offset2 + emacs_basis ();
      memcpy (emacs_ptr (reloc.emacs_offset), &pval, sizeof (pval));
      break;
    case RELOC_EMACS_DUMP_LV:
      eassume (reloc.length <= Lisp_Float);
      if (reloc.length == Lisp_Symbol)
        lv = make_lisp_symbol (dump_ptr (dump_base, reloc.u.dump_offset));
      else
        lv = make_lisp_ptr (dump_ptr (dump_base, reloc.u.dump_offset),
                            reloc.length);
      memcpy (emacs_ptr (reloc.emacs_offset), &lv, sizeof (lv));
      break;
    default:
      fatal ("unrecognied relocation type %d", (int) reloc.type);
    }
}

static void
dump_do_all_emacs_relocations (
  const struct dump_header *const header,
  const intptr_t dump_base)
{
  const dump_off nr_entries = header->emacs_relocs.nr_entries;
  struct emacs_reloc *r = dump_ptr (dump_base, header->emacs_relocs.offset);
  for (dump_off i = 0; i < nr_entries; ++i)
    dump_do_emacs_relocation (dump_base, r[i]);
}

enum dump_section
  {
   DS_HOT,
   DS_DISCARDABLE,
   DS_COLD,
   NUMBER_DUMP_SECTIONS,
  };

/* Load a dump from DUMP_FILENAME.  Return an error code.

   N.B. We run very early in initialization, so we can't use lisp,
   unwinding, xmalloc, and so on.  */
enum pdumper_load_result
pdumper_load (const char *dump_filename)
{
  enum pdumper_load_result err = PDUMPER_LOAD_ERROR;

  int dump_fd = -1;
  intptr_t dump_size;
  struct stat stat;
  intptr_t dump_base;
  int dump_page_size;
  dump_off adj_discardable_start;

  struct dump_bitset mark_bits;
  bool free_mark_bits = false;
  size_t mark_bits_needed;

  struct dump_header header_buf;
  struct dump_header *header = &header_buf;
  struct dump_memory_map sections[NUMBER_DUMP_SECTIONS];

  memset (&header_buf, 0, sizeof (header_buf));
  memset (&sections, 0, sizeof (sections));

  /* Overwriting an initialized Lisp universe will not go well.  */
  eassert (!initialized);

  /* We can load only one dump.  */
  eassert (!dump_loaded_p ());

  err = PDUMPER_LOAD_FILE_NOT_FOUND;
  dump_fd = emacs_open (dump_filename, O_RDONLY, 0);
  if (dump_fd < 0)
    goto out;

  err = PDUMPER_LOAD_FILE_NOT_FOUND;
  if (fstat (dump_fd, &stat) < 0)
    goto out;

  err = PDUMPER_LOAD_BAD_FILE_TYPE;
  if (stat.st_size > INTPTR_MAX)
    goto out;
  dump_size = (intptr_t) stat.st_size;

  err = PDUMPER_LOAD_BAD_FILE_TYPE;
  if (dump_size < sizeof (*header))
    goto out;

  err = PDUMPER_LOAD_BAD_FILE_TYPE;
  if (dump_read_all (dump_fd,
                     header,
                     sizeof (*header)) < sizeof (*header))
    goto out;

  err = PDUMPER_LOAD_BAD_FILE_TYPE;
  if (memcmp (header->magic, dump_magic, sizeof (dump_magic)) != 0)
    goto out;

  err = PDUMPER_LOAD_VERSION_MISMATCH;
  verify (sizeof (header->fingerprint) == sizeof (fingerprint));
  if (memcmp (header->fingerprint, fingerprint, sizeof (fingerprint)) != 0)
    {
      dump_fingerprint ("desired fingerprint", fingerprint);
      dump_fingerprint ("found fingerprint", header->fingerprint);
      goto out;
    }

  err = PDUMPER_LOAD_OOM;

  adj_discardable_start = header->discardable_start;
  dump_page_size = dump_get_page_size ();
  /* Snap to next page boundary.  */
  adj_discardable_start = ROUNDUP (
    adj_discardable_start,
    dump_page_size);
  eassert (adj_discardable_start % dump_page_size == 0);
  eassert (adj_discardable_start <= header->cold_start);

  sections[DS_HOT].spec = (struct dump_memory_map_spec)
    {
     .fd = dump_fd,
     .size = adj_discardable_start,
     .offset = 0,
     .protection = DUMP_MEMORY_ACCESS_READWRITE,
    };

  sections[DS_DISCARDABLE].spec = (struct dump_memory_map_spec)
    {
     .fd = dump_fd,
     .size = header->cold_start - adj_discardable_start,
     .offset = adj_discardable_start,
     .protection = DUMP_MEMORY_ACCESS_READWRITE,
    };

  sections[DS_COLD].spec = (struct dump_memory_map_spec)
    {
     .fd = dump_fd,
     .size = dump_size - header->cold_start,
     .offset = header->cold_start,
     .protection = DUMP_MEMORY_ACCESS_READWRITE,
    };

  if (!dump_mmap_contiguous (sections, ARRAYELTS (sections)))
    goto out;

  err = PDUMPER_LOAD_ERROR;
  mark_bits_needed =
    DIVIDE_ROUND_UP (header->discardable_start, GCALIGNMENT);
  if (!dump_bitset_init (&mark_bits, mark_bits_needed))
    goto out;
  free_mark_bits = true;

  /* Point of no return.  */
  err = PDUMPER_LOAD_SUCCESS;
  dump_base = (intptr_t) sections[DS_HOT].mapping;
  gflags.dumped_with_pdumper_ = true;
  free_mark_bits = false;
  dump_private.header = *header;
  dump_private.mark_bits = mark_bits;
  dump_public.start = dump_base;
  dump_public.end = dump_public.start + dump_size;

  dump_do_all_dump_relocations (header, dump_base);
  dump_do_all_emacs_relocations (header, dump_base);

  dump_mmap_discard_contents (&sections[DS_DISCARDABLE]);
  for (int i = 0; i < ARRAYELTS (sections); ++i)
    dump_mmap_reset (&sections[i]);

  /* Run the functions Emacs registered for doing post-dump-load
     initialization.  */
  for (int i = 0; i < nr_dump_hooks; ++i)
    dump_hooks[i] ();
  initialized = true;

 out:
  for (int i = 0; i < ARRAYELTS (sections); ++i)
    dump_mmap_release (&sections[i]);
  if (free_mark_bits)
    dump_bitset_destroy (&mark_bits);
  if (dump_fd >= 0)
    emacs_close (dump_fd);
  return err;
}

DEFUN ("pdumper-stats",
       Fpdumper_stats, Spdumper_stats,
       0, 0, 0,
       doc: /* Return statistics about the portable dumper.  */)
     (void)
{
  Lisp_Object stats = Qnil;
  if (dumped_with_pdumper_p ())
    dump_push (&stats, Fcons (Qdumped_with_pdumper, Qt));
  return Fnreverse (stats);
}

#endif /* HAVE_PDUMPER */

\f

void
syms_of_pdumper (void)
{
#ifdef HAVE_PDUMPER
  defsubr (&Sdump_emacs_portable);
  defsubr (&Sdump_emacs_portable__sort_predicate);
  defsubr (&Sdump_emacs_portable__sort_predicate_copied);
  DEFSYM (Qdump_emacs_portable__sort_predicate,
          "dump-emacs-portable--sort-predicate");
  DEFSYM (Qdump_emacs_portable__sort_predicate_copied,
          "dump-emacs-portable--sort-predicate-copied");
  DEFSYM (Qdumped_with_pdumper, "dumped-with-pdumper");
  defsubr (&Spdumper_stats);
#endif /* HAVE_PDUMPER */
}

debug log:

solving a05b2c4 ...
found a05b2c4 in https://git.savannah.gnu.org/cgit/emacs.git

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).