summaryrefslogtreecommitdiff
path: root/output/outcoff.c
blob: d0fcb775184cd8200f2ea3623a841fe98acf048c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
/* ----------------------------------------------------------------------- *
 *
 *   Copyright 1996-2010 The NASM Authors - All Rights Reserved
 *   See the file AUTHORS included with the NASM distribution for
 *   the specific copyright holders.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following
 *   conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ----------------------------------------------------------------------- */

/*
 * outcoff.c    output routines for the Netwide Assembler to produce
 *              COFF object files (for DJGPP and Win32)
 */

#include "compiler.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <inttypes.h>

#include "nasm.h"
#include "nasmlib.h"
#include "saa.h"
#include "raa.h"
#include "eval.h"
#include "output/outform.h"
#include "output/outlib.h"
#include "output/pecoff.h"

#if defined(OF_COFF) || defined(OF_WIN32) || defined(OF_WIN64)

/*
 * Notes on COFF:
 *
 * (0) When I say `standard COFF' below, I mean `COFF as output and
 * used by DJGPP'. I assume DJGPP gets it right.
 *
 * (1) Win32 appears to interpret the term `relative relocation'
 * differently from standard COFF. Standard COFF understands a
 * relative relocation to mean that during relocation you add the
 * address of the symbol you're referencing, and subtract the base
 * address of the section you're in. Win32 COFF, by contrast, seems
 * to add the address of the symbol and then subtract the address
 * of THE BYTE AFTER THE RELOCATED DWORD. Hence the two formats are
 * subtly incompatible.
 *
 * (2) Win32 doesn't bother putting any flags in the header flags
 * field (at offset 0x12 into the file).
 *
 * (3) Win32 uses some extra flags into the section header table:
 * it defines flags 0x80000000 (writable), 0x40000000 (readable)
 * and 0x20000000 (executable), and uses them in the expected
 * combinations. It also defines 0x00100000 through 0x00700000 for
 * section alignments of 1 through 64 bytes.
 *
 * (4) Both standard COFF and Win32 COFF seem to use the DWORD
 * field directly after the section name in the section header
 * table for something strange: they store what the address of the
 * section start point _would_ be, if you laid all the sections end
 * to end starting at zero. Dunno why. Microsoft's documentation
 * lists this field as "Virtual Size of Section", which doesn't
 * seem to fit at all. In fact, Win32 even includes non-linked
 * sections such as .drectve in this calculation.
 *
 * Newer versions of MASM seem to have changed this to be zero, and
 * that apparently matches the COFF spec, so go with that.
 *
 * (5) Standard COFF does something very strange to common
 * variables: the relocation point for a common variable is as far
 * _before_ the variable as its size stretches out _after_ it. So
 * we must fix up common variable references. Win32 seems to be
 * sensible on this one.
 */

/* Flag which version of COFF we are currently outputting. */
static bool win32, win64;

static int32_t imagebase_sect;
#define WRT_IMAGEBASE "..imagebase"

struct Reloc {
    struct Reloc *next;
    int32_t address;            /* relative to _start_ of section */
    int32_t symbol;             /* symbol number */
    enum {
        SECT_SYMBOLS,
        ABS_SYMBOL,
        REAL_SYMBOLS
    } symbase;                  /* relocation for symbol number :) */
    int16_t type;
};

struct Symbol {
    char name[9];
    int32_t strpos;             /* string table position of name */
    int32_t value;              /* address, or COMMON variable size */
    int section;                /* section number where it's defined
                                 * - in COFF codes, not NASM codes */
    bool is_global;             /* is it a global symbol or not? */
    int16_t type;               /* 0 - notype, 0x20 - function */
    int32_t namlen;             /* full name length */
};

static char coff_infile[FILENAME_MAX];

struct Section {
    struct SAA *data;
    uint32_t len;
    int nrelocs;
    int32_t index;
    struct Reloc *head, **tail;
    uint32_t flags;             /* section flags */
    char *name;
    int32_t namepos;            /* Offset of name into the strings table */
    int32_t pos, relpos;
};

/*
 * Some common section flags by default
 */
#define TEXT_FLAGS_WIN                                  \
        (IMAGE_SCN_CNT_CODE                     |       \
         IMAGE_SCN_ALIGN_16BYTES                |       \
         IMAGE_SCN_MEM_EXECUTE                  |       \
         IMAGE_SCN_MEM_READ)
#define TEXT_FLAGS_DOS                                  \
        (IMAGE_SCN_CNT_CODE)

#define DATA_FLAGS_WIN                                  \
        (IMAGE_SCN_CNT_INITIALIZED_DATA         |       \
         IMAGE_SCN_ALIGN_4BYTES                 |       \
         IMAGE_SCN_MEM_READ                     |       \
         IMAGE_SCN_MEM_WRITE)
#define DATA_FLAGS_DOS                                  \
        (IMAGE_SCN_CNT_INITIALIZED_DATA)

#define BSS_FLAGS_WIN                                   \
        (IMAGE_SCN_CNT_UNINITIALIZED_DATA       |       \
         IMAGE_SCN_ALIGN_4BYTES                 |       \
         IMAGE_SCN_MEM_READ                     |       \
         IMAGE_SCN_MEM_WRITE)
#define BSS_FLAGS_DOS                                   \
        (IMAGE_SCN_CNT_UNINITIALIZED_DATA)

#define RDATA_FLAGS_WIN                                 \
        (IMAGE_SCN_CNT_INITIALIZED_DATA         |       \
         IMAGE_SCN_ALIGN_8BYTES                 |       \
         IMAGE_SCN_MEM_READ)

#define RDATA_FLAGS_DOS                                 \
        (IMAGE_SCN_CNT_INITIALIZED_DATA)

#define PDATA_FLAGS                                     \
        (IMAGE_SCN_CNT_INITIALIZED_DATA         |       \
         IMAGE_SCN_ALIGN_4BYTES                 |       \
         IMAGE_SCN_MEM_READ)

#define XDATA_FLAGS                                     \
        (IMAGE_SCN_CNT_INITIALIZED_DATA         |       \
         IMAGE_SCN_ALIGN_8BYTES                 |       \
         IMAGE_SCN_MEM_READ)

#define INFO_FLAGS                                      \
        (IMAGE_SCN_ALIGN_1BYTES                 |       \
         IMAGE_SCN_LNK_INFO                     |       \
         IMAGE_SCN_LNK_REMOVE)

#define TEXT_FLAGS      ((win32 | win64) ? TEXT_FLAGS_WIN  : TEXT_FLAGS_DOS)
#define DATA_FLAGS      ((win32 | win64) ? DATA_FLAGS_WIN  : DATA_FLAGS_DOS)
#define BSS_FLAGS       ((win32 | win64) ? BSS_FLAGS_WIN   : BSS_FLAGS_DOS)
#define RDATA_FLAGS     ((win32 | win64) ? RDATA_FLAGS_WIN : RDATA_FLAGS_DOS)

#define SECT_DELTA 32
static struct Section **sects;
static int nsects, sectlen;

static struct SAA *syms;
static uint32_t nsyms;

static int32_t def_seg;

static int initsym;

static struct RAA *bsym, *symval;

static struct SAA *strs;
static uint32_t strslen;

static void coff_gen_init(void);
static void coff_sect_write(struct Section *, const uint8_t *, uint32_t);
static void coff_write(void);
static void coff_section_header(char *, int32_t, int32_t, int32_t, int32_t, int32_t, int, int32_t);
static void coff_write_relocs(struct Section *);
static void coff_write_symbols(void);

static void coff_win32_init(void)
{
    win32 = true;
    win64 = false;
    coff_gen_init();
}

static void coff_win64_init(void)
{
    maxbits = 64;
    win32 = false;
    win64 = true;
    coff_gen_init();
    imagebase_sect = seg_alloc()+1;
    define_label(WRT_IMAGEBASE, imagebase_sect, 0, NULL, false, false);
}

static void coff_std_init(void)
{
    win32 = win64 = false;
    coff_gen_init();
}

static void coff_gen_init(void)
{

    sects = NULL;
    nsects = sectlen = 0;
    syms = saa_init(sizeof(struct Symbol));
    nsyms = 0;
    bsym = raa_init();
    symval = raa_init();
    strs = saa_init(1);
    strslen = 0;
    def_seg = seg_alloc();
}

static void coff_cleanup(int debuginfo)
{
    struct Reloc *r;
    int i;

    (void)debuginfo;

    coff_write();
    for (i = 0; i < nsects; i++) {
        if (sects[i]->data)
            saa_free(sects[i]->data);
        while (sects[i]->head) {
            r = sects[i]->head;
            sects[i]->head = sects[i]->head->next;
            nasm_free(r);
        }
        nasm_free(sects[i]->name);
        nasm_free(sects[i]);
    }
    nasm_free(sects);
    saa_free(syms);
    raa_free(bsym);
    raa_free(symval);
    saa_free(strs);
}

static int coff_make_section(char *name, uint32_t flags)
{
    struct Section *s;
    size_t namelen;

    s = nasm_zalloc(sizeof(*s));

    if (flags != BSS_FLAGS)
        s->data = saa_init(1);
    s->tail = &s->head;
    if (!strcmp(name, ".text"))
        s->index = def_seg;
    else
        s->index = seg_alloc();
    s->namepos = -1;
    namelen = strlen(name);
    if (namelen > 8) {
        if (win32 || win64) {
            s->namepos = strslen + 4;
            saa_wbytes(strs, name, namelen + 1);
            strslen += namelen + 1;
        } else {
            namelen = 8;
        }
    }
    s->name = nasm_malloc(namelen + 1);
    strncpy(s->name, name, namelen);
    s->name[namelen] = '\0';
    s->flags = flags;

    if (nsects >= sectlen) {
        sectlen += SECT_DELTA;
        sects = nasm_realloc(sects, sectlen * sizeof(*sects));
    }
    sects[nsects++] = s;

    return nsects - 1;
}

static inline int32_t coff_sectalign_flags(unsigned int align)
{
    return (ilog2_32(align) + 1) << 20;
}

static int32_t coff_section_names(char *name, int pass, int *bits)
{
    char *p;
    uint32_t flags, align_and = ~0L, align_or = 0L;
    int i;

    /*
     * Set default bits.
     */
    if (!name) {
        if(win64)
            *bits = 64;
        else
            *bits = 32;
    }

    if (!name)
        return def_seg;

    p = name;
    while (*p && !nasm_isspace(*p))
        p++;
    if (*p)
        *p++ = '\0';
    if (strlen(name) > 8) {
        if (!win32 && !win64) {
            nasm_error(ERR_WARNING,
                       "COFF section names limited to 8 characters:  truncating");
            name[8] = '\0';
        }
    }
    flags = 0;

    while (*p && nasm_isspace(*p))
        p++;
    while (*p) {
        char *q = p;
        while (*p && !nasm_isspace(*p))
            p++;
        if (*p)
            *p++ = '\0';
        while (*p && nasm_isspace(*p))
            p++;

        if (!nasm_stricmp(q, "code") || !nasm_stricmp(q, "text")) {
            flags = TEXT_FLAGS;
        } else if (!nasm_stricmp(q, "data")) {
            flags = DATA_FLAGS;
        } else if (!nasm_stricmp(q, "rdata")) {
            if (win32 | win64)
                flags = RDATA_FLAGS;
            else {
                flags = DATA_FLAGS;     /* gotta do something */
                nasm_error(ERR_NONFATAL, "standard COFF does not support"
                      " read-only data sections");
            }
        } else if (!nasm_stricmp(q, "bss")) {
            flags = BSS_FLAGS;
        } else if (!nasm_stricmp(q, "info")) {
            if (win32 | win64)
                flags = INFO_FLAGS;
            else {
                flags = DATA_FLAGS;     /* gotta do something */
                nasm_error(ERR_NONFATAL, "standard COFF does not support"
                      " informational sections");
            }
        } else if (!nasm_strnicmp(q, "align=", 6)) {
            if (!(win32 | win64))
                nasm_error(ERR_NONFATAL, "standard COFF does not support"
                      " section alignment specification");
            else {
                if (q[6 + strspn(q + 6, "0123456789")])
                    nasm_error(ERR_NONFATAL,
                          "argument to `align' is not numeric");
                else {
                    unsigned int align = atoi(q + 6);
                    if (!align || ((align - 1) & align))
                        nasm_error(ERR_NONFATAL, "argument to `align' is not a"
                              " power of two");
                    else if (align > 64)
                        nasm_error(ERR_NONFATAL, "Win32 cannot align sections"
                              " to better than 64-byte boundaries");
                    else {
                        align_and = ~0x00F00000L;
                        align_or  = coff_sectalign_flags(align);
                    }
                }
            }
        }
    }

    for (i = 0; i < nsects; i++)
        if (!strcmp(name, sects[i]->name))
            break;
    if (i == nsects) {
        if (!flags) {
            if (!strcmp(name, ".data"))
                flags = DATA_FLAGS;
            else if (!strcmp(name, ".rdata"))
                flags = RDATA_FLAGS;
            else if (!strcmp(name, ".bss"))
                flags = BSS_FLAGS;
            else if (win64 && !strcmp(name, ".pdata"))
                flags = PDATA_FLAGS;
            else if (win64 && !strcmp(name, ".xdata"))
                flags = XDATA_FLAGS;
            else
                flags = TEXT_FLAGS;
        }
        i = coff_make_section(name, flags);
        if (flags)
            sects[i]->flags = flags;
        sects[i]->flags &= align_and;
        sects[i]->flags |= align_or;
    } else if (pass == 1) {
        /* Check if any flags are specified */
        if (flags) {
            unsigned int align_flags = flags & IMAGE_SCN_ALIGN_MASK;

            /* Warn if non-alignment flags differ */
            if ((flags ^ sects[i]->flags) & ~IMAGE_SCN_ALIGN_MASK) {
                nasm_error(ERR_WARNING, "section attributes ignored on"
                    " redeclaration of section `%s'", name);
            }
            /* Check if alignment might be needed */
            if (align_flags > IMAGE_SCN_ALIGN_1BYTES) {
                unsigned int sect_align_flags = sects[i]->flags & IMAGE_SCN_ALIGN_MASK;

                /* Compute the actual alignment */
                unsigned int align = 1u << ((align_flags - IMAGE_SCN_ALIGN_1BYTES) >> 20);

                /* Update section header as needed */
                if (align_flags > sect_align_flags) {
                    sects[i]->flags = (sects[i]->flags & ~IMAGE_SCN_ALIGN_MASK) | align_flags;
                }
                /* Check if not already aligned */
                if (sects[i]->len % align) {
                    unsigned int padding = (align - sects[i]->len) % align;
                    /* We need to write at most 8095 bytes */
                    char buffer[8095];
                    if (sects[i]->flags & IMAGE_SCN_CNT_CODE) {
                        /* Fill with INT 3 instructions */
                        memset(buffer, 0xCC, padding);
                    } else {
                        memset(buffer, 0x00, padding);
                    }
                    saa_wbytes(sects[i]->data, buffer, padding);
                    sects[i]->len += padding;
                }
            }
        }
    }

    return sects[i]->index;
}

static void coff_deflabel(char *name, int32_t segment, int64_t offset,
                          int is_global, char *special)
{
    int pos = strslen + 4;
    struct Symbol *sym;

    if (special)
        nasm_error(ERR_NONFATAL, "COFF format does not support any"
              " special symbol types");

    if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
        if (strcmp(name,WRT_IMAGEBASE))
            nasm_error(ERR_NONFATAL, "unrecognized special symbol `%s'", name);
        return;
    }

    if (strlen(name) > 8) {
        size_t nlen = strlen(name)+1;
        saa_wbytes(strs, name, nlen);
        strslen += nlen;
    } else
        pos = -1;

    sym = saa_wstruct(syms);

    sym->strpos = pos;
    sym->namlen = strlen(name);
    if (pos == -1)
        strcpy(sym->name, name);
    sym->is_global = !!is_global;
    sym->type = 0;              /* Default to T_NULL (no type) */
    if (segment == NO_SEG)
        sym->section = -1;      /* absolute symbol */
    else {
        int i;
        sym->section = 0;
        for (i = 0; i < nsects; i++)
            if (segment == sects[i]->index) {
                sym->section = i + 1;
                break;
            }
        if (!sym->section)
            sym->is_global = true;
    }
    if (is_global == 2)
        sym->value = offset;
    else
        sym->value = (sym->section == 0 ? 0 : offset);

    /*
     * define the references from external-symbol segment numbers
     * to these symbol records.
     */
    if (sym->section == 0)
        bsym = raa_write(bsym, segment, nsyms);

    if (segment != NO_SEG)
        symval = raa_write(symval, segment, sym->section ? 0 : sym->value);

    nsyms++;
}

static int32_t coff_add_reloc(struct Section *sect, int32_t segment,
                              int16_t type)
{
    struct Reloc *r;

    r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
    sect->tail = &r->next;
    r->next = NULL;

    r->address = sect->len;
    if (segment == NO_SEG) {
        r->symbol = 0, r->symbase = ABS_SYMBOL;
    } else {
        int i;
        r->symbase = REAL_SYMBOLS;
        for (i = 0; i < nsects; i++) {
            if (segment == sects[i]->index) {
                r->symbol = i * 2;
                r->symbase = SECT_SYMBOLS;
                break;
            }
        }
        if (r->symbase == REAL_SYMBOLS)
            r->symbol = raa_read(bsym, segment);
    }
    r->type = type;

    sect->nrelocs++;

    /*
     * Return the fixup for standard COFF common variables.
     */
    if (r->symbase == REAL_SYMBOLS && !(win32 | win64))
        return raa_read(symval, segment);

    return 0;
}

static void coff_out(int32_t segto, const void *data,
                     enum out_type type, uint64_t size,
                     int32_t segment, int32_t wrt)
{
    struct Section *s;
    uint8_t mydata[8], *p;
    int i;

    if (wrt != NO_SEG && !win64) {
        wrt = NO_SEG;           /* continue to do _something_ */
        nasm_error(ERR_NONFATAL, "WRT not supported by COFF output formats");
    }

    /*
     * handle absolute-assembly (structure definitions)
     */
    if (segto == NO_SEG) {
        if (type != OUT_RESERVE)
            nasm_error(ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
                  " space");
        return;
    }

    s = NULL;
    for (i = 0; i < nsects; i++) {
        if (segto == sects[i]->index) {
            s = sects[i];
            break;
        }
    }
    if (!s) {
        int tempint;            /* ignored */
        if (segto != coff_section_names(".text", 2, &tempint))
            nasm_error(ERR_PANIC, "strange segment conditions in COFF driver");
        else
            s = sects[nsects - 1];
    }

    /* magically default to 'wrt ..imagebase' in .pdata and .xdata */
    if (win64 && wrt == NO_SEG) {
        if (!strcmp(s->name,".pdata") || !strcmp(s->name,".xdata"))
            wrt = imagebase_sect;
    }

    if (!s->data && type != OUT_RESERVE) {
        nasm_error(ERR_WARNING, "attempt to initialize memory in"
              " BSS section `%s': ignored", s->name);
        s->len += realsize(type, size);
        return;
    }

    if (type == OUT_RESERVE) {
        if (s->data) {
            nasm_error(ERR_WARNING, "uninitialised space declared in"
                  " non-BSS section `%s': zeroing", s->name);
            coff_sect_write(s, NULL, size);
        } else
            s->len += size;
    } else if (type == OUT_RAWDATA) {
        if (segment != NO_SEG)
            nasm_error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
        coff_sect_write(s, data, size);
    } else if (type == OUT_ADDRESS) {
        if (!(win64)) {
            if (size != 4 && (segment != NO_SEG || wrt != NO_SEG)) {
                nasm_error(ERR_NONFATAL, "COFF format does not support non-32-bit"
                      " relocations");
            } else {
                int32_t fix = 0;
                if (segment != NO_SEG || wrt != NO_SEG) {
                    if (wrt != NO_SEG) {
                        nasm_error(ERR_NONFATAL, "COFF format does not support"
                              " WRT types");
                    } else if (segment % 2) {
                        nasm_error(ERR_NONFATAL, "COFF format does not support"
                              " segment base references");
                    } else
                        fix = coff_add_reloc(s, segment, IMAGE_REL_I386_DIR32);
                }
                p = mydata;
                WRITELONG(p, *(int64_t *)data + fix);
                coff_sect_write(s, mydata, size);
            }
        } else {
            int32_t fix = 0;
            p = mydata;
            if (size == 8) {
                if (wrt == imagebase_sect) {
                    nasm_error(ERR_NONFATAL, "operand size mismatch: 'wrt "
                               WRT_IMAGEBASE "' is a 32-bit operand");
                }
                fix = coff_add_reloc(s, segment, IMAGE_REL_AMD64_ADDR64);
                WRITEDLONG(p, *(int64_t *)data + fix);
                coff_sect_write(s, mydata, size);
            } else {
                fix = coff_add_reloc(s, segment,
                        wrt == imagebase_sect ?	IMAGE_REL_AMD64_ADDR32NB:
                                                IMAGE_REL_AMD64_ADDR32);
                WRITELONG(p, *(int64_t *)data + fix);
                coff_sect_write(s, mydata, size);
            }
        }
    } else if (type == OUT_REL2ADR) {
        nasm_error(ERR_NONFATAL, "COFF format does not support 16-bit"
              " relocations");
    } else if (type == OUT_REL4ADR) {
        if (segment == segto && !(win64))  /* Acceptable for RIP-relative */
            nasm_error(ERR_PANIC, "intra-segment OUT_REL4ADR");
        else if (segment == NO_SEG && win32)
            nasm_error(ERR_NONFATAL, "Win32 COFF does not correctly support"
                  " relative references to absolute addresses");
        else {
            int32_t fix = 0;
            if (segment != NO_SEG && segment % 2) {
                nasm_error(ERR_NONFATAL, "COFF format does not support"
                      " segment base references");
            } else
                fix = coff_add_reloc(s, segment,
                        win64 ? IMAGE_REL_AMD64_REL32 : IMAGE_REL_I386_REL32);
            p = mydata;
            if (win32 | win64) {
                WRITELONG(p, *(int64_t *)data + 4 - size + fix);
            } else {
                WRITELONG(p, *(int64_t *)data - (size + s->len) + fix);
            }
            coff_sect_write(s, mydata, 4L);
        }

    }
}

static void coff_sect_write(struct Section *sect,
                            const uint8_t *data, uint32_t len)
{
    saa_wbytes(sect->data, data, len);
    sect->len += len;
}

typedef struct tagString {
    struct tagString *next;
    int len;
    char *String;
} STRING;

#define EXPORT_SECTION_NAME ".drectve"
#define EXPORT_SECTION_FLAGS INFO_FLAGS
/*
 * #define EXPORT_SECTION_NAME ".text"
 * #define EXPORT_SECTION_FLAGS TEXT_FLAGS
 */

static STRING *Exports = NULL;
static struct Section *directive_sec;
void AddExport(char *name)
{
    STRING *rvp = Exports, *newS;

    newS = (STRING *) nasm_malloc(sizeof(STRING));
    newS->len = strlen(name);
    newS->next = NULL;
    newS->String = (char *)nasm_malloc(newS->len + 1);
    strcpy(newS->String, name);
    if (rvp == NULL) {
        int i;

        for (i = 0; i < nsects; i++) {
            if (!strcmp(EXPORT_SECTION_NAME, sects[i]->name))
                break;
        }

        if (i == nsects)
            i = coff_make_section(EXPORT_SECTION_NAME, EXPORT_SECTION_FLAGS);

        directive_sec = sects[i];
        Exports = newS;
    } else {
        while (rvp->next) {
            if (!strcmp(rvp->String, name))
                return;
            rvp = rvp->next;
        }
        rvp->next = newS;
    }
}

static void BuildExportTable(STRING **rvp)
{
    STRING *p, *t;

    if (!rvp || !*rvp)
        return;

    list_for_each_safe(p, t, *rvp) {
        coff_sect_write(directive_sec, (uint8_t *)"-export:", 8);
        coff_sect_write(directive_sec, (uint8_t *)p->String, p->len);
        coff_sect_write(directive_sec, (uint8_t *)" ", 1);
        nasm_free(p->String);
        nasm_free(p);
    }

    *rvp = NULL;
}

static int coff_directives(enum directives directive, char *value, int pass)
{
    switch (directive) {
    case D_EXPORT:
    {
        char *q, *name;

        if (pass == 2)
            return 1;           /* ignore in pass two */
        name = q = value;
        while (*q && !nasm_isspace(*q))
            q++;
        if (nasm_isspace(*q)) {
            *q++ = '\0';
            while (*q && nasm_isspace(*q))
                q++;
        }

        if (!*name) {
            nasm_error(ERR_NONFATAL, "`export' directive requires export name");
            return 1;
        }
        if (*q) {
            nasm_error(ERR_NONFATAL, "unrecognized export qualifier `%s'", q);
            return 1;
        }
        AddExport(name);
        return 1;
    }
    case D_SAFESEH:
    {
        static int sxseg=-1;
        int i;

        if (!win32) /* Only applicable for -f win32 */
            return 0;

        if (sxseg == -1) {
            for (i = 0; i < nsects; i++)
                if (!strcmp(".sxdata",sects[i]->name))
                    break;
            if (i == nsects)
                sxseg = coff_make_section(".sxdata", IMAGE_SCN_LNK_INFO);
            else
                sxseg = i;
        }
        /*
         * pass0 == 2 is the only time when the full set of symbols are
         * guaranteed to be present; it is the final output pass.
         */
        if (pass0 == 2) {
            uint32_t n;
            saa_rewind(syms);
            for (n = 0; n < nsyms; n++) {
                struct Symbol *sym = saa_rstruct(syms);
                bool equals;

                /*
                 * sym->strpos is biased by 4, because symbol
                 * table is prefixed with table length
                 */
                if (sym->strpos >=4) {
                    char *name = nasm_malloc(sym->namlen+1);
                    saa_fread(strs, sym->strpos-4, name, sym->namlen);
                    name[sym->namlen] = '\0';
                    equals = !strcmp(value,name);
                    nasm_free(name);
                } else {
                    equals = !strcmp(value,sym->name);
                }

                if (equals) {
                    /*
                     * this value arithmetics effectively reflects
                     * initsym in coff_write(): 2 for file, 1 for
                     * .absolute and two per each section
                     */
                    unsigned char value[4],*p=value;
                    WRITELONG(p,n + 2 + 1 + nsects*2);
                    coff_sect_write(sects[sxseg],value,4);
                    sym->type = 0x20;
                    break;
                }
            }
            if (n == nsyms) {
                nasm_error(ERR_NONFATAL,
                           "`safeseh' directive requires valid symbol");
            }
        }
        return 1;
    }
    default:
        return 0;
    }
}

/* handle relocations storm, valid for win32/64 only */
static inline void coff_adjust_relocs(struct Section *s)
{
    if (s->nrelocs < IMAGE_SCN_MAX_RELOC)
        return;
#ifdef OF_COFF
    else
    {
        if (ofmt == &of_coff)
            nasm_error(ERR_FATAL,
                       "Too many relocations (%d) for section `%s'",
                       s->nrelocs, s->name);
    }
#endif

    s->flags |= IMAGE_SCN_LNK_NRELOC_OVFL;
    s->nrelocs++;
}

static void coff_write(void)
{
    int32_t pos, sympos, vsize;
    int i;

    /* fill in the .drectve section with -export's */
    BuildExportTable(&Exports);

    if (win32) {
        /* add default value for @feat.00, this allows to 'link /safeseh' */
        uint32_t n;

        saa_rewind(syms);
        for (n = 0; n < nsyms; n++) {
            struct Symbol *sym = saa_rstruct(syms);
            if (sym->strpos == -1 && !strcmp("@feat.00",sym->name))
                break;
        }
        if (n == nsyms)
            coff_deflabel("@feat.00", NO_SEG, 1, 0, NULL);
    }

    /*
     * Work out how big the file will get.
     * Calculate the start of the `real' symbols at the same time.
     * Check for massive relocations.
     */
    pos = 0x14 + 0x28 * nsects;
    initsym = 3;                /* two for the file, one absolute */
    for (i = 0; i < nsects; i++) {
        if (sects[i]->data) {
            coff_adjust_relocs(sects[i]);
            sects[i]->pos = pos;
            pos += sects[i]->len;
            sects[i]->relpos = pos;
            pos += 10 * sects[i]->nrelocs;
        } else
            sects[i]->pos = sects[i]->relpos = 0L;
        initsym += 2;           /* two for each section */
    }
    sympos = pos;

    /*
     * Output the COFF header.
     */
    if (win64)
        i = IMAGE_FILE_MACHINE_AMD64;
    else
        i = IMAGE_FILE_MACHINE_I386;
    fwriteint16_t(i,                    ofile); /* machine type */
    fwriteint16_t(nsects,               ofile); /* number of sections */
    fwriteint32_t(time(NULL),           ofile); /* time stamp */
    fwriteint32_t(sympos,               ofile);
    fwriteint32_t(nsyms + initsym,      ofile);
    fwriteint16_t(0,                    ofile); /* no optional header */
    /* Flags: 32-bit, no line numbers. Win32 doesn't even bother with them. */
    fwriteint16_t((win32 | win64) ? 0 : 0x104, ofile);

    /*
     * Output the section headers.
     */
    vsize = 0L;
    for (i = 0; i < nsects; i++) {
        coff_section_header(sects[i]->name, sects[i]->namepos, vsize, sects[i]->len,
                            sects[i]->pos, sects[i]->relpos,
                            sects[i]->nrelocs, sects[i]->flags);
        vsize += sects[i]->len;
    }

    /*
     * Output the sections and their relocations.
     */
    for (i = 0; i < nsects; i++)
        if (sects[i]->data) {
            saa_fpwrite(sects[i]->data, ofile);
            coff_write_relocs(sects[i]);
        }

    /*
     * Output the symbol and string tables.
     */
    coff_write_symbols();
    fwriteint32_t(strslen + 4, ofile);     /* length includes length count */
    saa_fpwrite(strs, ofile);
}

static void coff_section_header(char *name, int32_t namepos, int32_t vsize,
                                int32_t datalen, int32_t datapos,
                                int32_t relpos, int nrelocs, int32_t flags)
{
    char padname[8];

    (void)vsize;

    if (namepos == -1) {
        strncpy(padname, name, 8);
        fwrite(padname, 8, 1, ofile);
    } else {
        /*
         * If name is longer than 8 bytes, write '/' followed
         * by offset into the strings table represented as
         * decimal number.
         */
        namepos = namepos % 100000000;
        padname[0] = '/';
        padname[1] = '0' + (namepos / 1000000);
        namepos = namepos % 1000000;
        padname[2] = '0' + (namepos / 100000);
        namepos = namepos % 100000;
        padname[3] = '0' + (namepos / 10000);
        namepos = namepos % 10000;
        padname[4] = '0' + (namepos / 1000);
        namepos = namepos % 1000;
        padname[5] = '0' + (namepos / 100);
        namepos = namepos % 100;
        padname[6] = '0' + (namepos / 10);
        namepos = namepos % 10;
        padname[7] = '0' + (namepos);
        fwrite(padname, 8, 1, ofile);
    }

    fwriteint32_t(0,            ofile); /* Virtual size field - set to 0 or vsize */
    fwriteint32_t(0L,           ofile); /* RVA/offset - we ignore */
    fwriteint32_t(datalen,      ofile);
    fwriteint32_t(datapos,      ofile);
    fwriteint32_t(relpos,       ofile);
    fwriteint32_t(0L,           ofile); /* no line numbers - we don't do 'em */

    /*
     * a special case -- if there are too many relocs
     * we have to put IMAGE_SCN_MAX_RELOC here and write
     * the real relocs number into VirtualAddress of first
     * relocation
     */
    if (flags & IMAGE_SCN_LNK_NRELOC_OVFL)
        fwriteint16_t(IMAGE_SCN_MAX_RELOC, ofile);
    else
        fwriteint16_t(nrelocs,  ofile);

    fwriteint16_t(0,            ofile); /* again, no line numbers */
    fwriteint32_t(flags,        ofile);
}

static void coff_write_relocs(struct Section *s)
{
    struct Reloc *r;

    /* a real number of relocations if needed */
    if (s->flags & IMAGE_SCN_LNK_NRELOC_OVFL) {
        fwriteint32_t(s->nrelocs, ofile);
        fwriteint32_t(0, ofile);
        fwriteint16_t(0, ofile);
    }

    for (r = s->head; r; r = r->next) {
        fwriteint32_t(r->address, ofile);
        fwriteint32_t(r->symbol + (r->symbase == REAL_SYMBOLS ? initsym :
                                   r->symbase == ABS_SYMBOL   ? initsym - 1 :
                                   r->symbase == SECT_SYMBOLS ? 2 : 0),
                      ofile);
        fwriteint16_t(r->type, ofile);
    }
}

static void coff_symbol(char *name, int32_t strpos, int32_t value,
                        int section, int type, int storageclass, int aux)
{
    char padname[8];

    if (name) {
        strncpy(padname, name, 8);
        fwrite(padname, 8, 1, ofile);
    } else {
        fwriteint32_t(0, ofile);
        fwriteint32_t(strpos, ofile);
    }

    fwriteint32_t(value,        ofile);
    fwriteint16_t(section,      ofile);
    fwriteint16_t(type,         ofile);

    fputc(storageclass, ofile);
    fputc(aux, ofile);
}

static void coff_write_symbols(void)
{
    char filename[18];
    uint32_t i;

    /*
     * The `.file' record, and the file name auxiliary record.
     */
    coff_symbol(".file", 0L, 0L, -2, 0, 0x67, 1);
    strncpy(filename, coff_infile, 18);
    fwrite(filename, 18, 1, ofile);

    /*
     * The section records, with their auxiliaries.
     */
    memset(filename, 0, 18);    /* useful zeroed buffer */

    for (i = 0; i < (uint32_t) nsects; i++) {
        coff_symbol(sects[i]->name, 0L, 0L, i + 1, 0, 3, 1);
        fwriteint32_t(sects[i]->len,    ofile);
        fwriteint16_t(sects[i]->nrelocs,ofile);
        fwrite(filename, 12, 1, ofile);
    }

    /*
     * The absolute symbol, for relative-to-absolute relocations.
     */
    coff_symbol(".absolut", 0L, 0L, -1, 0, 3, 0);

    /*
     * The real symbols.
     */
    saa_rewind(syms);
    for (i = 0; i < nsyms; i++) {
        struct Symbol *sym = saa_rstruct(syms);
        coff_symbol(sym->strpos == -1 ? sym->name : NULL,
                    sym->strpos, sym->value, sym->section,
                    sym->type, sym->is_global ? 2 : 3, 0);
    }
}

static void coff_sectalign(int32_t seg, unsigned int value)
{
    struct Section *s = NULL;
    uint32_t align;
    int i;

    for (i = 0; i < nsects; i++) {
        if (sects[i]->index == seg) {
            s = sects[i];
            break;
        }
    }

    if (!s || !is_power2(value))
        return;

    /* DOS has limitation on 64 bytes */
    if (!(win32 | win64) && value > 64)
        return;

    align = (s->flags & IMAGE_SCN_ALIGN_MASK);
    value = coff_sectalign_flags(value);
    if (value > align)
        s->flags = (s->flags & ~IMAGE_SCN_ALIGN_MASK) | value;
}

static int32_t coff_segbase(int32_t segment)
{
    return segment;
}

static void coff_std_filename(char *inname, char *outname)
{
    strcpy(coff_infile, inname);
    standard_extension(inname, outname, ".o");
}

static void coff_win32_filename(char *inname, char *outname)
{
    strcpy(coff_infile, inname);
    standard_extension(inname, outname, ".obj");
}

extern macros_t coff_stdmac[];

static int coff_set_info(enum geninfo type, char **val)
{
    (void)type;
    (void)val;
    return 0;
}
#endif /* defined(OF_COFF) || defined(OF_WIN32) */

#ifdef OF_COFF

struct ofmt of_coff = {
    "COFF (i386) object files (e.g. DJGPP for DOS)",
    "coff",
    0,
    null_debug_arr,
    &null_debug_form,
    coff_stdmac,
    coff_std_init,
    coff_set_info,
    coff_out,
    coff_deflabel,
    coff_section_names,
    coff_sectalign,
    coff_segbase,
    coff_directives,
    coff_std_filename,
    coff_cleanup
};

#endif

#ifdef OF_WIN32

struct ofmt of_win32 = {
    "Microsoft Win32 (i386) object files",
    "win32",
    0,
    null_debug_arr,
    &null_debug_form,
    coff_stdmac,
    coff_win32_init,
    coff_set_info,
    coff_out,
    coff_deflabel,
    coff_section_names,
    coff_sectalign,
    coff_segbase,
    coff_directives,
    coff_win32_filename,
    coff_cleanup
};

#endif

#ifdef OF_WIN64

struct ofmt of_win64 = {
    "Microsoft Win64 (x86-64) object files",
    "win64",
    0,
    null_debug_arr,
    &null_debug_form,
    coff_stdmac,
    coff_win64_init,
    coff_set_info,
    coff_out,
    coff_deflabel,
    coff_section_names,
    coff_sectalign,
    coff_segbase,
    coff_directives,
    coff_win32_filename,
    coff_cleanup
};

#endif