/* 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 *, const 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; 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]); } 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; 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 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; 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 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; 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->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, const 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; 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)) 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, const unsigned char *data, unsigned long 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) directive_sec = sects[coff_make_section (EXPORT_SECTION_NAME, EXPORT_SECTION_FLAGS)]; else directive_sec = sects[i]; Exports = newS; } else { while (rvp->Next) { if (!strcmp(rvp->String, name)) return; rvp = rvp->Next; } rvp->Next = newS; } } void BuildExportTable(void) { STRING *rvp = Exports, *next; unsigned char buf[256]; int len; if (rvp == NULL) return; while (rvp) { len = sprintf((char *)buf, "-export:%s ", rvp->String); coff_sect_write(directive_sec, buf, len); rvp = rvp->Next; } next = Exports; while ((rvp = next)) { next = rvp->Next; nasm_free(rvp->String); nasm_free(rvp); } Exports = NULL; } static int coff_directives(char *directive, char *value, int pass) { if (!strcmp(directive, "export")) { char *q, *name; if (pass == 2) return 1; /* ignore in pass two */ name = q = value; while (*q && !isspace(*q)) q++; if (isspace(*q)) { *q++ = '\0'; while (*q && isspace(*q)) q++; } if (!*name) { error(ERR_NONFATAL, "`export' directive requires export name"); return 1; } if (*q) { error(ERR_NONFATAL, "unrecognised export qualifier `%s'", q); return 1; } AddExport(name); return 1; } return 0; } static void coff_write(void) { long pos, sympos, vsize; int i; BuildExportTable(); /* fill in the .drectve section with -export's */ /* * 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; i < nsects; i++) { if (sects[i]->data) { 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; i < nsects; i++) { coff_section_header(sects[i]->name, 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, 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", "%imacro export 1+.nolist", "[export %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