/* outcoff.c output routines for the Netwide Assembler to produce * COFF object files (for DJGPP and Win32) * * The Netwide Assembler is copyright (C) 1996 Simon Tatham and * Julian Hall. All rights reserved. The software is * redistributable under the licence given in the file "Licence" * distributed in the NASM archive. */ #include #include #include #include #include #include "nasm.h" #include "nasmlib.h" #include "outform.h" #if defined(OF_COFF) || defined(OF_WIN32) /* * 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. * * (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 int win32; struct Reloc { struct Reloc *next; long address; /* relative to _start_ of section */ long symbol; /* symbol number */ enum { SECT_SYMBOLS, ABS_SYMBOL, REAL_SYMBOLS } symbase; /* relocation for symbol number :) */ int relative; /* TRUE or FALSE */ }; struct Symbol { char name[9]; long strpos; /* string table position of name */ int section; /* section number where it's defined * - in COFF codes, not NASM codes */ int is_global; /* is it a global symbol or not? */ long value; /* address, or COMMON variable size */ }; static FILE *coffp; static efunc error; static char coff_infile[FILENAME_MAX]; struct Section { struct SAA *data; unsigned long len; int nrelocs; long index; struct Reloc *head, **tail; unsigned long flags; /* section flags */ char name[9]; long pos, relpos; }; #define TEXT_FLAGS (win32 ? 0x60500020L : 0x20L) #define DATA_FLAGS (win32 ? 0xC0300040L : 0x40L) #define BSS_FLAGS (win32 ? 0xC0300080L : 0x80L) #define INFO_FLAGS 0x00100A00L #define RDATA_FLAGS (win32 ? 0x40400040L : 0x40L) #define SECT_DELTA 32 static struct Section **sects; static int nsects, sectlen; static struct SAA *syms; static unsigned long nsyms; static long def_seg; static int initsym; static struct RAA *bsym, *symval; static struct SAA *strs; static unsigned long strslen; static void coff_gen_init(FILE *, efunc); static void coff_sect_write (struct Section *, unsigned char *, unsigned long); static void coff_write (void); static void coff_section_header (char *, long, long, long, long, int, long); static void coff_write_relocs (struct Section *); static void coff_write_symbols (void); static void coff_win32_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval) { win32 = TRUE; (void) ldef; /* placate optimisers */ coff_gen_init(fp, errfunc); } static void coff_std_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval) { win32 = FALSE; (void) ldef; /* placate optimisers */ coff_gen_init(fp, errfunc); } static void coff_gen_init(FILE *fp, efunc errfunc) { coffp = fp; error = errfunc; sects = NULL; nsects = sectlen = 0; syms = saa_init((long)sizeof(struct Symbol)); nsyms = 0; bsym = raa_init(); symval = raa_init(); strs = saa_init(1L); strslen = 0; def_seg = seg_alloc(); } static void coff_cleanup(int debuginfo) { struct Reloc *r; int i; (void) debuginfo; coff_write(); fclose (coffp); for (i=0; idata) 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]); } nasm_free (sects); saa_free (syms); raa_free (bsym); raa_free (symval); saa_free (strs); } static int coff_make_section (char *name, unsigned long flags) { struct Section *s; s = nasm_malloc (sizeof(*s)); if (flags != BSS_FLAGS) s->data = saa_init (1L); else s->data = NULL; s->head = NULL; s->tail = &s->head; s->len = 0; s->nrelocs = 0; if (!strcmp(name, ".text")) s->index = def_seg; else s->index = seg_alloc(); strncpy (s->name, name, 8); s->name[8] = '\0'; s->flags = flags; if (nsects >= sectlen) sects = nasm_realloc (sects, (sectlen += SECT_DELTA)*sizeof(*sects)); sects[nsects++] = s; return nsects-1; } static long coff_section_names (char *name, int pass, int *bits) { char *p; unsigned long flags, align_and = ~0L, align_or = 0L; int i; /* * Default is 32 bits. */ if (!name) *bits = 32; if (!name) return def_seg; p = name; while (*p && !isspace(*p)) p++; if (*p) *p++ = '\0'; if (strlen(name) > 8) { error (ERR_WARNING, "COFF section names limited to 8 characters:" " truncating"); name[8] = '\0'; } flags = 0; while (*p && isspace(*p)) p++; while (*p) { char *q = p; while (*p && !isspace(*p)) p++; if (*p) *p++ = '\0'; while (*p && 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) flags = RDATA_FLAGS; else { flags = DATA_FLAGS; /* gotta do something */ 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) flags = INFO_FLAGS; else { flags = DATA_FLAGS; /* gotta do something */ error (ERR_NONFATAL, "standard COFF does not support" " informational sections"); } } else if (!nasm_strnicmp(q,"align=",6)) { if (!win32) error (ERR_NONFATAL, "standard COFF does not support" " section alignment specification"); else { if (q[6+strspn(q+6,"0123456789")]) error(ERR_NONFATAL, "argument to `align' is not numeric"); else { unsigned int align = atoi(q+6); if (!align || ((align-1) & align)) error(ERR_NONFATAL, "argument to `align' is not a" " power of two"); else if (align > 64) error(ERR_NONFATAL, "Win32 cannot align sections" " to better than 64-byte boundaries"); else { align_and = ~0x00F00000L; align_or = (align == 1 ? 0x00100000L : align == 2 ? 0x00200000L : align == 4 ? 0x00300000L : align == 8 ? 0x00400000L : align == 16 ? 0x00500000L : align == 32 ? 0x00600000L : 0x00700000L); } } } } } for (i=0; iname)) 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 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) { if (flags) error (ERR_WARNING, "section attributes ignored on" " redeclaration of section `%s'", name); } return sects[i]->index; } static void coff_deflabel (char *name, long segment, long offset, int is_global, char *special) { int pos = strslen+4; struct Symbol *sym; if (special) error (ERR_NONFATAL, "binary format does not support any" " special symbol types"); if (name[0] == '.' && name[1] == '.' && name[2] != '@') { error (ERR_NONFATAL, "unrecognised special symbol `%s'", name); return; } if (strlen(name) > 8) { saa_wbytes (strs, name, (long)(1+strlen(name))); strslen += 1+strlen(name); } else pos = -1; sym = saa_wstruct (syms); sym->strpos = pos; if (pos == -1) strcpy (sym->name, name); sym->is_global = !!is_global; if (segment == NO_SEG) sym->section = -1; /* absolute symbol */ else { int i; sym->section = 0; for (i=0; iindex) { 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 long coff_add_reloc (struct Section *sect, long segment, int relative) { 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; iindex) { r->symbol = i*2; r->symbase = SECT_SYMBOLS; break; } if (r->symbase == REAL_SYMBOLS) r->symbol = raa_read (bsym, segment); } r->relative = relative; sect->nrelocs++; /* * Return the fixup for standard COFF common variables. */ if (r->symbase == REAL_SYMBOLS && !win32) return raa_read (symval, segment); else return 0; } static void coff_out (long segto, void *data, unsigned long type, long segment, long wrt) { struct Section *s; long realbytes = type & OUT_SIZMASK; unsigned char mydata[4], *p; int i; if (wrt != NO_SEG) { wrt = NO_SEG; /* continue to do _something_ */ error (ERR_NONFATAL, "WRT not supported by COFF output formats"); } type &= OUT_TYPMASK; /* * handle absolute-assembly (structure definitions) */ if (segto == NO_SEG) { if (type != OUT_RESERVE) error (ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]" " space"); return; } s = NULL; for (i=0; iindex) { s = sects[i]; break; } if (!s) { int tempint; /* ignored */ if (segto != coff_section_names (".text", 2, &tempint)) error (ERR_PANIC, "strange segment conditions in COFF driver"); else s = sects[nsects-1]; } if (!s->data && type != OUT_RESERVE) { error(ERR_WARNING, "attempt to initialise memory in" " BSS section `%s': ignored", s->name); if (type == OUT_REL2ADR) realbytes = 2; else if (type == OUT_REL4ADR) realbytes = 4; s->len += realbytes; return; } if (type == OUT_RESERVE) { if (s->data) { error(ERR_WARNING, "uninitialised space declared in" " non-BSS section `%s': zeroing", s->name); coff_sect_write (s, NULL, realbytes); } else s->len += realbytes; } else if (type == OUT_RAWDATA) { if (segment != NO_SEG) error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG"); coff_sect_write (s, data, realbytes); } else if (type == OUT_ADDRESS) { if (realbytes != 4 && (segment != NO_SEG || wrt != NO_SEG)) error(ERR_NONFATAL, "COFF format does not support non-32-bit" " relocations"); else { long fix = 0; if (segment != NO_SEG || wrt != NO_SEG) { if (wrt != NO_SEG) { error(ERR_NONFATAL, "COFF format does not support" " WRT types"); } else if (segment % 2) { error(ERR_NONFATAL, "COFF format does not support" " segment base references"); } else fix = coff_add_reloc (s, segment, FALSE); } p = mydata; WRITELONG (p, *(long *)data + fix); coff_sect_write (s, mydata, realbytes); } } else if (type == OUT_REL2ADR) { error(ERR_NONFATAL, "COFF format does not support 16-bit" " relocations"); } else if (type == OUT_REL4ADR) { if (segment == segto) error(ERR_PANIC, "intra-segment OUT_REL4ADR"); else if (segment == NO_SEG && win32) error(ERR_NONFATAL, "Win32 COFF does not correctly support" " relative references to absolute addresses"); else { long fix = 0; if (segment != NO_SEG && segment % 2) { error(ERR_NONFATAL, "COFF format does not support" " segment base references"); } else fix = coff_add_reloc (s, segment, TRUE); p = mydata; if (win32) { WRITELONG (p, *(long*)data + 4 - realbytes + fix); } else { WRITELONG (p, *(long*)data-(realbytes + s->len) + fix); } coff_sect_write (s, mydata, 4L); } } } static void coff_sect_write (struct Section *sect, unsigned char *data, unsigned long len) { saa_wbytes (sect->data, data, len); sect->len += len; } static int coff_directives (char *directive, char *value, int pass) { return 0; } static void coff_write (void) { long pos, sympos, vsize; int i; /* * Work out how big the file will get. Calculate the start of * the `real' symbols at the same time. */ pos = 0x14 + 0x28 * nsects; initsym = 3; /* two for the file, one absolute */ for (i=0; idata) { 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. */ fwriteshort (0x14C, coffp); /* MACHINE_i386 */ fwriteshort (nsects, coffp); /* number of sections */ fwritelong (time(NULL), coffp); /* time stamp */ fwritelong (sympos, coffp); fwritelong (nsyms + initsym, coffp); fwriteshort (0, coffp); /* no optional header */ /* Flags: 32-bit, no line numbers. Win32 doesn't even bother with them. */ fwriteshort (win32 ? 0 : 0x104, coffp); /* * Output the section headers. */ vsize = 0L; for (i=0; iname, 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; idata) { saa_fpwrite (sects[i]->data, coffp); coff_write_relocs (sects[i]); } /* * Output the symbol and string tables. */ coff_write_symbols(); fwritelong (strslen+4, coffp); /* length includes length count */ saa_fpwrite (strs, coffp); } static void coff_section_header (char *name, long vsize, long datalen, long datapos, long relpos, int nrelocs, long flags) { char padname[8]; memset (padname, 0, 8); strncpy (padname, name, 8); fwrite (padname, 8, 1, coffp); fwritelong (vsize, coffp); fwritelong (0L, coffp); /* RVA/offset - we ignore */ fwritelong (datalen, coffp); fwritelong (datapos, coffp); fwritelong (relpos, coffp); fwritelong (0L, coffp); /* no line numbers - we don't do 'em */ fwriteshort (nrelocs, coffp); fwriteshort (0, coffp); /* again, no line numbers */ fwritelong (flags, coffp); } static void coff_write_relocs (struct Section *s) { struct Reloc *r; for (r = s->head; r; r = r->next) { fwritelong (r->address, coffp); fwritelong (r->symbol + (r->symbase == REAL_SYMBOLS ? initsym : r->symbase == ABS_SYMBOL ? initsym-1 : r->symbase == SECT_SYMBOLS ? 2 : 0), coffp); /* * Strange: Microsoft's COFF documentation says 0x03 for an * absolute relocation, but both Visual C++ and DJGPP agree * that in fact it's 0x06. I'll use 0x06 until someone * argues. */ fwriteshort (r->relative ? 0x14 : 0x06, coffp); } } static void coff_symbol (char *name, long strpos, long value, int section, int type, int aux) { char padname[8]; if (name) { memset (padname, 0, 8); strncpy (padname, name, 8); fwrite (padname, 8, 1, coffp); } else { fwritelong (0L, coffp); fwritelong (strpos, coffp); } fwritelong (value, coffp); fwriteshort (section, coffp); fwriteshort (0, coffp); fputc (type, coffp); fputc (aux, coffp); } static void coff_write_symbols (void) { char filename[18]; unsigned long i; /* * The `.file' record, and the file name auxiliary record. */ coff_symbol (".file", 0L, 0L, -2, 0x67, 1); memset (filename, 0, 18); strncpy (filename, coff_infile, 18); fwrite (filename, 18, 1, coffp); /* * The section records, with their auxiliaries. */ memset (filename, 0, 18); /* useful zeroed buffer */ for (i = 0; i < nsects; i++) { coff_symbol (sects[i]->name, 0L, 0L, i+1, 3, 1); fwritelong (sects[i]->len, coffp); fwriteshort (sects[i]->nrelocs, coffp); fwrite (filename, 12, 1, coffp); } /* * The absolute symbol, for relative-to-absolute relocations. */ coff_symbol (".absolut", 0L, 0L, -1, 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->is_global ? 2 : 3, 0); } } static long coff_segbase (long segment) { return segment; } static void coff_std_filename (char *inname, char *outname, efunc error) { strcpy(coff_infile, inname); standard_extension (inname, outname, ".o", error); } static void coff_win32_filename (char *inname, char *outname, efunc error) { strcpy(coff_infile, inname); standard_extension (inname, outname, ".obj", error); } static const char *coff_stdmac[] = { "%define __SECT__ [section .text]", "%macro __NASM_CDecl__ 1", "%endmacro", NULL }; static int coff_set_info(enum geninfo type, char **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", NULL, null_debug_arr, &null_debug_form, coff_stdmac, coff_std_init, coff_set_info, coff_out, coff_deflabel, coff_section_names, coff_segbase, coff_directives, coff_std_filename, coff_cleanup }; #endif #ifdef OF_WIN32 struct ofmt of_win32 = { "Microsoft Win32 (i386) object files", "win32", NULL, null_debug_arr, &null_debug_form, coff_stdmac, coff_win32_init, coff_set_info, coff_out, coff_deflabel, coff_section_names, coff_segbase, coff_directives, coff_win32_filename, coff_cleanup }; #endif