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 const 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",