1 /* outcoff.c output routines for the Netwide Assembler to produce
2 * COFF object files (for DJGPP and Win32)
4 * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
5 * Julian Hall. All rights reserved. The software is
6 * redistributable under the licence given in the file "Licence"
7 * distributed in the NASM archive.
20 #if defined(OF_COFF) || defined(OF_WIN32)
25 * (0) When I say `standard COFF' below, I mean `COFF as output and
26 * used by DJGPP'. I assume DJGPP gets it right.
28 * (1) Win32 appears to interpret the term `relative relocation'
29 * differently from standard COFF. Standard COFF understands a
30 * relative relocation to mean that during relocation you add the
31 * address of the symbol you're referencing, and subtract the base
32 * address of the section you're in. Win32 COFF, by contrast, seems
33 * to add the address of the symbol and then subtract the address
34 * of THE BYTE AFTER THE RELOCATED DWORD. Hence the two formats are
35 * subtly incompatible.
37 * (2) Win32 doesn't bother putting any flags in the header flags
38 * field (at offset 0x12 into the file).
40 * (3) Win32 uses some extra flags into the section header table:
41 * it defines flags 0x80000000 (writable), 0x40000000 (readable)
42 * and 0x20000000 (executable), and uses them in the expected
43 * combinations. It also defines 0x00100000 through 0x00700000 for
44 * section alignments of 1 through 64 bytes.
46 * (4) Both standard COFF and Win32 COFF seem to use the DWORD
47 * field directly after the section name in the section header
48 * table for something strange: they store what the address of the
49 * section start point _would_ be, if you laid all the sections end
50 * to end starting at zero. Dunno why. Microsoft's documentation
51 * lists this field as "Virtual Size of Section", which doesn't
52 * seem to fit at all. In fact, Win32 even includes non-linked
53 * sections such as .drectve in this calculation.
55 * (5) Standard COFF does something very strange to common
56 * variables: the relocation point for a common variable is as far
57 * _before_ the variable as its size stretches out _after_ it. So
58 * we must fix up common variable references. Win32 seems to be
59 * sensible on this one.
62 /* Flag which version of COFF we are currently outputting. */
67 long address; /* relative to _start_ of section */
68 long symbol; /* symbol number */
73 } symbase; /* relocation for symbol number :) */
74 int relative; /* TRUE or FALSE */
79 long strpos; /* string table position of name */
80 int section; /* section number where it's defined
81 * - in COFF codes, not NASM codes */
82 int is_global; /* is it a global symbol or not? */
83 long value; /* address, or COMMON variable size */
88 static char coff_infile[FILENAME_MAX];
95 struct Reloc *head, **tail;
96 unsigned long flags; /* section flags */
101 #define TEXT_FLAGS (win32 ? 0x60500020L : 0x20L)
102 #define DATA_FLAGS (win32 ? 0xC0300040L : 0x40L)
103 #define BSS_FLAGS (win32 ? 0xC0300080L : 0x80L)
104 #define INFO_FLAGS 0x00100A00L
105 #define RDATA_FLAGS (win32 ? 0x40400040L : 0x40L)
107 #define SECT_DELTA 32
108 static struct Section **sects;
109 static int nsects, sectlen;
111 static struct SAA *syms;
112 static unsigned long nsyms;
118 static struct RAA *bsym, *symval;
120 static struct SAA *strs;
121 static unsigned long strslen;
123 static void coff_gen_init(FILE *, efunc);
124 static void coff_sect_write (struct Section *, unsigned char *,
126 static void coff_write (void);
127 static void coff_section_header (char *, long, long, long, long, int, long);
128 static void coff_write_relocs (struct Section *);
129 static void coff_write_symbols (void);
131 static void coff_win32_init(FILE *fp, efunc errfunc,
132 ldfunc ldef, evalfunc eval)
135 (void) ldef; /* placate optimisers */
136 coff_gen_init(fp, errfunc);
139 static void coff_std_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
142 (void) ldef; /* placate optimisers */
143 coff_gen_init(fp, errfunc);
146 static void coff_gen_init(FILE *fp, efunc errfunc)
152 nsects = sectlen = 0;
153 syms = saa_init((long)sizeof(struct Symbol));
159 def_seg = seg_alloc();
162 static void coff_cleanup(int debuginfo)
171 for (i=0; i<nsects; i++) {
173 saa_free (sects[i]->data);
174 while (sects[i]->head) {
176 sects[i]->head = sects[i]->head->next;
179 nasm_free (sects[i]);
188 static int coff_make_section (char *name, unsigned long flags)
192 s = nasm_malloc (sizeof(*s));
194 if (flags != BSS_FLAGS)
195 s->data = saa_init (1L);
202 if (!strcmp(name, ".text"))
205 s->index = seg_alloc();
206 strncpy (s->name, name, 8);
210 if (nsects >= sectlen)
211 sects = nasm_realloc (sects, (sectlen += SECT_DELTA)*sizeof(*sects));
217 static long coff_section_names (char *name, int pass, int *bits)
220 unsigned long flags, align_and = ~0L, align_or = 0L;
224 * Default is 32 bits.
233 while (*p && !isspace(*p)) p++;
235 if (strlen(name) > 8) {
236 error (ERR_WARNING, "COFF section names limited to 8 characters:"
242 while (*p && isspace(*p)) p++;
245 while (*p && !isspace(*p)) p++;
247 while (*p && isspace(*p)) p++;
249 if (!nasm_stricmp(q, "code") || !nasm_stricmp(q, "text")) {
251 } else if (!nasm_stricmp(q, "data")) {
253 } else if (!nasm_stricmp(q, "rdata")) {
257 flags = DATA_FLAGS; /* gotta do something */
258 error (ERR_NONFATAL, "standard COFF does not support"
259 " read-only data sections");
261 } else if (!nasm_stricmp(q, "bss")) {
263 } else if (!nasm_stricmp(q, "info")) {
267 flags = DATA_FLAGS; /* gotta do something */
268 error (ERR_NONFATAL, "standard COFF does not support"
269 " informational sections");
271 } else if (!nasm_strnicmp(q,"align=",6)) {
273 error (ERR_NONFATAL, "standard COFF does not support"
274 " section alignment specification");
276 if (q[6+strspn(q+6,"0123456789")])
277 error(ERR_NONFATAL, "argument to `align' is not numeric");
279 unsigned int align = atoi(q+6);
280 if (!align || ((align-1) & align))
281 error(ERR_NONFATAL, "argument to `align' is not a"
284 error(ERR_NONFATAL, "Win32 cannot align sections"
285 " to better than 64-byte boundaries");
287 align_and = ~0x00F00000L;
288 align_or = (align == 1 ? 0x00100000L :
289 align == 2 ? 0x00200000L :
290 align == 4 ? 0x00300000L :
291 align == 8 ? 0x00400000L :
292 align == 16 ? 0x00500000L :
293 align == 32 ? 0x00600000L : 0x00700000L);
300 for (i=0; i<nsects; i++)
301 if (!strcmp(name, sects[i]->name))
305 if (!strcmp(name, ".data"))
307 else if (!strcmp(name, ".rdata"))
309 else if (!strcmp(name, ".bss"))
314 i = coff_make_section (name, flags);
316 sects[i]->flags = flags;
317 sects[i]->flags &= align_and;
318 sects[i]->flags |= align_or;
319 } else if (pass == 1) {
321 error (ERR_WARNING, "section attributes ignored on"
322 " redeclaration of section `%s'", name);
325 return sects[i]->index;
328 static void coff_deflabel (char *name, long segment, long offset,
329 int is_global, char *special)
335 error (ERR_NONFATAL, "binary format does not support any"
336 " special symbol types");
338 if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
339 error (ERR_NONFATAL, "unrecognised special symbol `%s'", name);
343 if (strlen(name) > 8) {
344 saa_wbytes (strs, name, (long)(1+strlen(name)));
345 strslen += 1+strlen(name);
349 sym = saa_wstruct (syms);
353 strcpy (sym->name, name);
354 sym->is_global = !!is_global;
355 if (segment == NO_SEG)
356 sym->section = -1; /* absolute symbol */
360 for (i=0; i<nsects; i++)
361 if (segment == sects[i]->index) {
366 sym->is_global = TRUE;
371 sym->value = (sym->section == 0 ? 0 : offset);
374 * define the references from external-symbol segment numbers
375 * to these symbol records.
377 if (sym->section == 0)
378 bsym = raa_write (bsym, segment, nsyms);
380 if (segment != NO_SEG)
381 symval = raa_write (symval, segment, sym->section ? 0 : sym->value);
386 static long coff_add_reloc (struct Section *sect, long segment,
391 r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
392 sect->tail = &r->next;
395 r->address = sect->len;
396 if (segment == NO_SEG)
397 r->symbol = 0, r->symbase = ABS_SYMBOL;
400 r->symbase = REAL_SYMBOLS;
401 for (i=0; i<nsects; i++)
402 if (segment == sects[i]->index) {
404 r->symbase = SECT_SYMBOLS;
407 if (r->symbase == REAL_SYMBOLS)
408 r->symbol = raa_read (bsym, segment);
410 r->relative = relative;
415 * Return the fixup for standard COFF common variables.
417 if (r->symbase == REAL_SYMBOLS && !win32)
418 return raa_read (symval, segment);
423 static void coff_out (long segto, void *data, unsigned long type,
424 long segment, long wrt)
427 long realbytes = type & OUT_SIZMASK;
428 unsigned char mydata[4], *p;
432 wrt = NO_SEG; /* continue to do _something_ */
433 error (ERR_NONFATAL, "WRT not supported by COFF output formats");
439 * handle absolute-assembly (structure definitions)
441 if (segto == NO_SEG) {
442 if (type != OUT_RESERVE)
443 error (ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
449 for (i=0; i<nsects; i++)
450 if (segto == sects[i]->index) {
455 int tempint; /* ignored */
456 if (segto != coff_section_names (".text", 2, &tempint))
457 error (ERR_PANIC, "strange segment conditions in COFF driver");
462 if (!s->data && type != OUT_RESERVE) {
463 error(ERR_WARNING, "attempt to initialise memory in"
464 " BSS section `%s': ignored", s->name);
465 if (type == OUT_REL2ADR)
467 else if (type == OUT_REL4ADR)
473 if (type == OUT_RESERVE) {
475 error(ERR_WARNING, "uninitialised space declared in"
476 " non-BSS section `%s': zeroing", s->name);
477 coff_sect_write (s, NULL, realbytes);
480 } else if (type == OUT_RAWDATA) {
481 if (segment != NO_SEG)
482 error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
483 coff_sect_write (s, data, realbytes);
484 } else if (type == OUT_ADDRESS) {
485 if (realbytes != 4 && (segment != NO_SEG || wrt != NO_SEG))
486 error(ERR_NONFATAL, "COFF format does not support non-32-bit"
490 if (segment != NO_SEG || wrt != NO_SEG) {
492 error(ERR_NONFATAL, "COFF format does not support"
494 } else if (segment % 2) {
495 error(ERR_NONFATAL, "COFF format does not support"
496 " segment base references");
498 fix = coff_add_reloc (s, segment, FALSE);
501 WRITELONG (p, *(long *)data + fix);
502 coff_sect_write (s, mydata, realbytes);
504 } else if (type == OUT_REL2ADR) {
505 error(ERR_NONFATAL, "COFF format does not support 16-bit"
507 } else if (type == OUT_REL4ADR) {
508 if (segment == segto)
509 error(ERR_PANIC, "intra-segment OUT_REL4ADR");
510 else if (segment == NO_SEG && win32)
511 error(ERR_NONFATAL, "Win32 COFF does not correctly support"
512 " relative references to absolute addresses");
515 if (segment != NO_SEG && segment % 2) {
516 error(ERR_NONFATAL, "COFF format does not support"
517 " segment base references");
519 fix = coff_add_reloc (s, segment, TRUE);
522 WRITELONG (p, *(long*)data + 4 - realbytes + fix);
524 WRITELONG (p, *(long*)data-(realbytes + s->len) + fix);
526 coff_sect_write (s, mydata, 4L);
531 static void coff_sect_write (struct Section *sect,
532 unsigned char *data, unsigned long len)
534 saa_wbytes (sect->data, data, len);
538 static int coff_directives (char *directive, char *value, int pass)
543 static void coff_write (void)
545 long pos, sympos, vsize;
549 * Work out how big the file will get. Calculate the start of
550 * the `real' symbols at the same time.
552 pos = 0x14 + 0x28 * nsects;
553 initsym = 3; /* two for the file, one absolute */
554 for (i=0; i<nsects; i++) {
555 if (sects[i]->data) {
557 pos += sects[i]->len;
558 sects[i]->relpos = pos;
559 pos += 10 * sects[i]->nrelocs;
561 sects[i]->pos = sects[i]->relpos = 0L;
562 initsym += 2; /* two for each section */
567 * Output the COFF header.
569 fwriteshort (0x14C, coffp); /* MACHINE_i386 */
570 fwriteshort (nsects, coffp); /* number of sections */
571 fwritelong (time(NULL), coffp); /* time stamp */
572 fwritelong (sympos, coffp);
573 fwritelong (nsyms + initsym, coffp);
574 fwriteshort (0, coffp); /* no optional header */
575 /* Flags: 32-bit, no line numbers. Win32 doesn't even bother with them. */
576 fwriteshort (win32 ? 0 : 0x104, coffp);
579 * Output the section headers.
582 for (i=0; i<nsects; i++) {
583 coff_section_header (sects[i]->name, vsize, sects[i]->len,
584 sects[i]->pos, sects[i]->relpos,
585 sects[i]->nrelocs, sects[i]->flags);
586 vsize += sects[i]->len;
590 * Output the sections and their relocations.
592 for (i=0; i<nsects; i++)
593 if (sects[i]->data) {
594 saa_fpwrite (sects[i]->data, coffp);
595 coff_write_relocs (sects[i]);
599 * Output the symbol and string tables.
601 coff_write_symbols();
602 fwritelong (strslen+4, coffp); /* length includes length count */
603 saa_fpwrite (strs, coffp);
606 static void coff_section_header (char *name, long vsize,
607 long datalen, long datapos,
608 long relpos, int nrelocs, long flags)
612 memset (padname, 0, 8);
613 strncpy (padname, name, 8);
614 fwrite (padname, 8, 1, coffp);
615 fwritelong (vsize, coffp);
616 fwritelong (0L, coffp); /* RVA/offset - we ignore */
617 fwritelong (datalen, coffp);
618 fwritelong (datapos, coffp);
619 fwritelong (relpos, coffp);
620 fwritelong (0L, coffp); /* no line numbers - we don't do 'em */
621 fwriteshort (nrelocs, coffp);
622 fwriteshort (0, coffp); /* again, no line numbers */
623 fwritelong (flags, coffp);
626 static void coff_write_relocs (struct Section *s)
630 for (r = s->head; r; r = r->next) {
631 fwritelong (r->address, coffp);
632 fwritelong (r->symbol + (r->symbase == REAL_SYMBOLS ? initsym :
633 r->symbase == ABS_SYMBOL ? initsym-1 :
634 r->symbase == SECT_SYMBOLS ? 2 : 0), coffp);
636 * Strange: Microsoft's COFF documentation says 0x03 for an
637 * absolute relocation, but both Visual C++ and DJGPP agree
638 * that in fact it's 0x06. I'll use 0x06 until someone
641 fwriteshort (r->relative ? 0x14 : 0x06, coffp);
645 static void coff_symbol (char *name, long strpos, long value,
646 int section, int type, int aux)
651 memset (padname, 0, 8);
652 strncpy (padname, name, 8);
653 fwrite (padname, 8, 1, coffp);
655 fwritelong (0L, coffp);
656 fwritelong (strpos, coffp);
658 fwritelong (value, coffp);
659 fwriteshort (section, coffp);
660 fwriteshort (0, coffp);
665 static void coff_write_symbols (void)
671 * The `.file' record, and the file name auxiliary record.
673 coff_symbol (".file", 0L, 0L, -2, 0x67, 1);
674 memset (filename, 0, 18);
675 strncpy (filename, coff_infile, 18);
676 fwrite (filename, 18, 1, coffp);
679 * The section records, with their auxiliaries.
681 memset (filename, 0, 18); /* useful zeroed buffer */
683 for (i = 0; i < nsects; i++) {
684 coff_symbol (sects[i]->name, 0L, 0L, i+1, 3, 1);
685 fwritelong (sects[i]->len, coffp);
686 fwriteshort (sects[i]->nrelocs, coffp);
687 fwrite (filename, 12, 1, coffp);
691 * The absolute symbol, for relative-to-absolute relocations.
693 coff_symbol (".absolut", 0L, 0L, -1, 3, 0);
699 for (i = 0; i < nsyms; i++) {
700 struct Symbol *sym = saa_rstruct (syms);
701 coff_symbol (sym->strpos == -1 ? sym->name : NULL,
702 sym->strpos, sym->value, sym->section,
703 sym->is_global ? 2 : 3, 0);
707 static long coff_segbase (long segment)
712 static void coff_std_filename (char *inname, char *outname, efunc error)
714 strcpy(coff_infile, inname);
715 standard_extension (inname, outname, ".o", error);
718 static void coff_win32_filename (char *inname, char *outname, efunc error)
720 strcpy(coff_infile, inname);
721 standard_extension (inname, outname, ".obj", error);
724 static char *coff_stdmac[] = {
725 "%define __SECT__ [section .text]",
726 "%macro __NASM_CDecl__ 1",
731 static int coff_set_info(enum geninfo type, char **val)
735 #endif /* defined(OF_COFF) || defined(OF_WIN32) */
739 struct ofmt of_coff = {
740 "COFF (i386) object files (e.g. DJGPP for DOS)",
761 struct ofmt of_win32 = {
762 "Microsoft Win32 (i386) object files",