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-rw-r--r--output/outaout.c933
1 files changed, 933 insertions, 0 deletions
diff --git a/output/outaout.c b/output/outaout.c
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+++ b/output/outaout.c
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+/* outaout.c output routines for the Netwide Assembler to produce
+ * Linux a.out object files
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "nasm.h"
+#include "nasmlib.h"
+#include "outform.h"
+
+#if defined OF_AOUT || defined OF_AOUTB
+
+#define RELTYPE_ABSOLUTE 0x00
+#define RELTYPE_RELATIVE 0x01
+#define RELTYPE_GOTPC 0x01 /* no explicit GOTPC in a.out */
+#define RELTYPE_GOTOFF 0x10
+#define RELTYPE_GOT 0x10 /* distinct from GOTOFF bcos sym not sect */
+#define RELTYPE_PLT 0x21
+#define RELTYPE_SYMFLAG 0x08
+
+struct Reloc {
+ struct Reloc *next;
+ long address; /* relative to _start_ of section */
+ long symbol; /* symbol number or -ve section id */
+ int bytes; /* 2 or 4 */
+ int reltype; /* see above */
+};
+
+struct Symbol {
+ long strpos; /* string table position of name */
+ int type; /* symbol type - see flags below */
+ long value; /* address, or COMMON variable size */
+ long size; /* size for data or function exports */
+ long segment; /* back-reference used by gsym_reloc */
+ struct Symbol *next; /* list of globals in each section */
+ struct Symbol *nextfwd; /* list of unresolved-size symbols */
+ char *name; /* for unresolved-size symbols */
+ long symnum; /* index into symbol table */
+};
+
+/*
+ * Section IDs - used in Reloc.symbol when negative, and in
+ * Symbol.type when positive.
+ */
+#define SECT_ABS 2 /* absolute value */
+#define SECT_TEXT 4 /* text section */
+#define SECT_DATA 6 /* data section */
+#define SECT_BSS 8 /* bss section */
+#define SECT_MASK 0xE /* mask out any of the above */
+
+/*
+ * More flags used in Symbol.type.
+ */
+#define SYM_GLOBAL 1 /* it's a global symbol */
+#define SYM_DATA 0x100 /* used for shared libs */
+#define SYM_FUNCTION 0x200 /* used for shared libs */
+#define SYM_WITH_SIZE 0x4000 /* not output; internal only */
+
+/*
+ * Bit more explanation of symbol types: SECT_xxx denotes a local
+ * symbol. SECT_xxx|SYM_GLOBAL denotes a global symbol, defined in
+ * this module. Just SYM_GLOBAL, with zero value, denotes an
+ * external symbol referenced in this module. And just SYM_GLOBAL,
+ * but with a non-zero value, declares a C `common' variable, of
+ * size `value'.
+ */
+
+struct Section {
+ struct SAA *data;
+ unsigned long len, size, nrelocs;
+ long index;
+ struct Reloc *head, **tail;
+ struct Symbol *gsyms, *asym;
+};
+
+static struct Section stext, sdata, sbss;
+
+static struct SAA *syms;
+static unsigned long nsyms;
+
+static struct RAA *bsym;
+
+static struct SAA *strs;
+static unsigned long strslen;
+
+static struct Symbol *fwds;
+
+static FILE *aoutfp;
+static efunc error;
+static evalfunc evaluate;
+
+static int bsd;
+static int is_pic;
+
+static void aout_write(void);
+static void aout_write_relocs(struct Reloc *);
+static void aout_write_syms(void);
+static void aout_sect_write(struct Section *, unsigned char *, unsigned long);
+static void aout_pad_sections(void);
+static void aout_fixup_relocs(struct Section *);
+
+/*
+ * Special section numbers which are used to define special
+ * symbols, which can be used with WRT to provide PIC relocation
+ * types.
+ */
+static long aout_gotpc_sect, aout_gotoff_sect;
+static long aout_got_sect, aout_plt_sect;
+static long aout_sym_sect;
+
+static void aoutg_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
+{
+ aoutfp = fp;
+ error = errfunc;
+ evaluate = eval;
+ (void) ldef; /* placate optimisers */
+ stext.data = saa_init(1L); stext.head = NULL; stext.tail = &stext.head;
+ sdata.data = saa_init(1L); sdata.head = NULL; sdata.tail = &sdata.head;
+ stext.len = stext.size = sdata.len = sdata.size = sbss.len = 0;
+ stext.nrelocs = sdata.nrelocs = 0;
+ stext.gsyms = sdata.gsyms = sbss.gsyms = NULL;
+ stext.index = seg_alloc();
+ sdata.index = seg_alloc();
+ sbss.index = seg_alloc();
+ stext.asym = sdata.asym = sbss.asym = NULL;
+ syms = saa_init((long)sizeof(struct Symbol));
+ nsyms = 0;
+ bsym = raa_init();
+ strs = saa_init(1L);
+ strslen = 0;
+ fwds = NULL;
+}
+
+#ifdef OF_AOUT
+
+static void aout_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
+{
+ bsd = FALSE;
+ aoutg_init (fp, errfunc, ldef, eval);
+
+ aout_gotpc_sect = aout_gotoff_sect = aout_got_sect =
+ aout_plt_sect = aout_sym_sect = NO_SEG;
+}
+
+#endif
+
+#ifdef OF_AOUTB
+
+extern struct ofmt of_aoutb;
+
+static void aoutb_init(FILE *fp, efunc errfunc, ldfunc ldef, evalfunc eval)
+{
+ bsd = TRUE;
+ aoutg_init (fp, errfunc, ldef, eval);
+
+ is_pic = 0x00; /* may become 0x40 */
+
+ aout_gotpc_sect = seg_alloc();
+ ldef("..gotpc", aout_gotpc_sect+1, 0L, NULL, FALSE,FALSE,&of_aoutb,error);
+ aout_gotoff_sect = seg_alloc();
+ ldef("..gotoff", aout_gotoff_sect+1, 0L,NULL,FALSE,FALSE,&of_aoutb,error);
+ aout_got_sect = seg_alloc();
+ ldef("..got", aout_got_sect+1, 0L, NULL, FALSE,FALSE,&of_aoutb,error);
+ aout_plt_sect = seg_alloc();
+ ldef("..plt", aout_plt_sect+1, 0L, NULL, FALSE,FALSE,&of_aoutb,error);
+ aout_sym_sect = seg_alloc();
+ ldef("..sym", aout_sym_sect+1, 0L, NULL, FALSE,FALSE,&of_aoutb,error);
+}
+
+#endif
+
+static void aout_cleanup(int debuginfo)
+{
+ struct Reloc *r;
+
+ (void) debuginfo;
+
+ aout_pad_sections();
+ aout_fixup_relocs(&stext);
+ aout_fixup_relocs(&sdata);
+ aout_write();
+ fclose (aoutfp);
+ saa_free (stext.data);
+ while (stext.head) {
+ r = stext.head;
+ stext.head = stext.head->next;
+ nasm_free (r);
+ }
+ saa_free (sdata.data);
+ while (sdata.head) {
+ r = sdata.head;
+ sdata.head = sdata.head->next;
+ nasm_free (r);
+ }
+ saa_free (syms);
+ raa_free (bsym);
+ saa_free (strs);
+}
+
+static long aout_section_names (char *name, int pass, int *bits)
+{
+ /*
+ * Default to 32 bits.
+ */
+ if (!name)
+ *bits = 32;
+
+ if (!name)
+ return stext.index;
+
+ if (!strcmp(name, ".text"))
+ return stext.index;
+ else if (!strcmp(name, ".data"))
+ return sdata.index;
+ else if (!strcmp(name, ".bss"))
+ return sbss.index;
+ else
+ return NO_SEG;
+}
+
+static void aout_deflabel (char *name, long segment, long offset,
+ int is_global, char *special)
+{
+ int pos = strslen+4;
+ struct Symbol *sym;
+ int special_used = FALSE;
+
+ if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
+ /*
+ * This is a NASM special symbol. We never allow it into
+ * the a.out symbol table, even if it's a valid one. If it
+ * _isn't_ a valid one, we should barf immediately.
+ */
+ if (strcmp(name, "..gotpc") && strcmp(name, "..gotoff") &&
+ strcmp(name, "..got") && strcmp(name, "..plt") &&
+ strcmp(name, "..sym"))
+ error (ERR_NONFATAL, "unrecognised special symbol `%s'", name);
+ return;
+ }
+
+ if (is_global == 3) {
+ struct Symbol **s;
+ /*
+ * Fix up a forward-reference symbol size from the first
+ * pass.
+ */
+ for (s = &fwds; *s; s = &(*s)->nextfwd)
+ if (!strcmp((*s)->name, name)) {
+ struct tokenval tokval;
+ expr *e;
+ char *p = special;
+
+ while (*p && !isspace(*p)) p++;
+ while (*p && isspace(*p)) p++;
+ stdscan_reset();
+ stdscan_bufptr = p;
+ tokval.t_type = TOKEN_INVALID;
+ e = evaluate(stdscan, NULL, &tokval, NULL, 1, error, NULL);
+ if (e) {
+ if (!is_simple(e))
+ error (ERR_NONFATAL, "cannot use relocatable"
+ " expression as symbol size");
+ else
+ (*s)->size = reloc_value(e);
+ }
+
+ /*
+ * Remove it from the list of unresolved sizes.
+ */
+ nasm_free ((*s)->name);
+ *s = (*s)->nextfwd;
+ return;
+ }
+ return; /* it wasn't an important one */
+ }
+
+ saa_wbytes (strs, name, (long)(1+strlen(name)));
+ strslen += 1+strlen(name);
+
+ sym = saa_wstruct (syms);
+
+ sym->strpos = pos;
+ sym->type = is_global ? SYM_GLOBAL : 0;
+ sym->segment = segment;
+ if (segment == NO_SEG)
+ sym->type |= SECT_ABS;
+ else if (segment == stext.index) {
+ sym->type |= SECT_TEXT;
+ if (is_global) {
+ sym->next = stext.gsyms;
+ stext.gsyms = sym;
+ } else if (!stext.asym)
+ stext.asym = sym;
+ } else if (segment == sdata.index) {
+ sym->type |= SECT_DATA;
+ if (is_global) {
+ sym->next = sdata.gsyms;
+ sdata.gsyms = sym;
+ } else if (!sdata.asym)
+ sdata.asym = sym;
+ } else if (segment == sbss.index) {
+ sym->type |= SECT_BSS;
+ if (is_global) {
+ sym->next = sbss.gsyms;
+ sbss.gsyms = sym;
+ } else if (!sbss.asym)
+ sbss.asym = sym;
+ } else
+ sym->type = SYM_GLOBAL;
+ if (is_global == 2)
+ sym->value = offset;
+ else
+ sym->value = (sym->type == SYM_GLOBAL ? 0 : offset);
+
+ if (is_global && sym->type != SYM_GLOBAL) {
+ /*
+ * Global symbol exported _from_ this module. We must check
+ * the special text for type information.
+ */
+
+ if (special) {
+ int n = strcspn(special, " ");
+
+ if (!nasm_strnicmp(special, "function", n))
+ sym->type |= SYM_FUNCTION;
+ else if (!nasm_strnicmp(special, "data", n) ||
+ !nasm_strnicmp(special, "object", n))
+ sym->type |= SYM_DATA;
+ else
+ error(ERR_NONFATAL, "unrecognised symbol type `%.*s'",
+ n, special);
+ if (special[n]) {
+ struct tokenval tokval;
+ expr *e;
+ int fwd = FALSE;
+ char *saveme=stdscan_bufptr; /* bugfix? fbk 8/10/00 */
+
+ if (!bsd) {
+ error(ERR_NONFATAL, "Linux a.out does not support"
+ " symbol size information");
+ } else {
+ while (special[n] && isspace(special[n]))
+ n++;
+ /*
+ * We have a size expression; attempt to
+ * evaluate it.
+ */
+ sym->type |= SYM_WITH_SIZE;
+ stdscan_reset();
+ stdscan_bufptr = special+n;
+ tokval.t_type = TOKEN_INVALID;
+ e = evaluate(stdscan, NULL, &tokval, &fwd, 0, error, NULL);
+ if (fwd) {
+ sym->nextfwd = fwds;
+ fwds = sym;
+ sym->name = nasm_strdup(name);
+ } else if (e) {
+ if (!is_simple(e))
+ error (ERR_NONFATAL, "cannot use relocatable"
+ " expression as symbol size");
+ else
+ sym->size = reloc_value(e);
+ }
+ }
+ stdscan_bufptr=saveme; /* bugfix? fbk 8/10/00 */
+ }
+ special_used = TRUE;
+ }
+ }
+
+ /*
+ * define the references from external-symbol segment numbers
+ * to these symbol records.
+ */
+ if (segment != NO_SEG && segment != stext.index &&
+ segment != sdata.index && segment != sbss.index)
+ bsym = raa_write (bsym, segment, nsyms);
+ sym->symnum = nsyms;
+
+ nsyms++;
+ if (sym->type & SYM_WITH_SIZE)
+ nsyms++; /* and another for the size */
+
+ if (special && !special_used)
+ error(ERR_NONFATAL, "no special symbol features supported here");
+}
+
+static void aout_add_reloc (struct Section *sect, long segment,
+ int reltype, int bytes)
+{
+ struct Reloc *r;
+
+ r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
+ sect->tail = &r->next;
+ r->next = NULL;
+
+ r->address = sect->len;
+ r->symbol = (segment == NO_SEG ? -SECT_ABS :
+ segment == stext.index ? -SECT_TEXT :
+ segment == sdata.index ? -SECT_DATA :
+ segment == sbss.index ? -SECT_BSS :
+ raa_read(bsym, segment));
+ r->reltype = reltype;
+ if (r->symbol >= 0)
+ r->reltype |= RELTYPE_SYMFLAG;
+ r->bytes = bytes;
+
+ sect->nrelocs++;
+}
+
+/*
+ * This routine deals with ..got and ..sym relocations: the more
+ * complicated kinds. In shared-library writing, some relocations
+ * with respect to global symbols must refer to the precise symbol
+ * rather than referring to an offset from the base of the section
+ * _containing_ the symbol. Such relocations call to this routine,
+ * which searches the symbol list for the symbol in question.
+ *
+ * RELTYPE_GOT references require the _exact_ symbol address to be
+ * used; RELTYPE_ABSOLUTE references can be at an offset from the
+ * symbol. The boolean argument `exact' tells us this.
+ *
+ * Return value is the adjusted value of `addr', having become an
+ * offset from the symbol rather than the section. Should always be
+ * zero when returning from an exact call.
+ *
+ * Limitation: if you define two symbols at the same place,
+ * confusion will occur.
+ *
+ * Inefficiency: we search, currently, using a linked list which
+ * isn't even necessarily sorted.
+ */
+static long aout_add_gsym_reloc (struct Section *sect,
+ long segment, long offset,
+ int type, int bytes, int exact)
+{
+ struct Symbol *sym, *sm, *shead;
+ struct Reloc *r;
+
+ /*
+ * First look up the segment to find whether it's text, data,
+ * bss or an external symbol.
+ */
+ shead = NULL;
+ if (segment == stext.index)
+ shead = stext.gsyms;
+ else if (segment == sdata.index)
+ shead = sdata.gsyms;
+ else if (segment == sbss.index)
+ shead = sbss.gsyms;
+ if (!shead) {
+ if (exact && offset != 0)
+ error (ERR_NONFATAL, "unable to find a suitable global symbol"
+ " for this reference");
+ else
+ aout_add_reloc (sect, segment, type, bytes);
+ return offset;
+ }
+
+ if (exact) {
+ /*
+ * Find a symbol pointing _exactly_ at this one.
+ */
+ for (sym = shead; sym; sym = sym->next)
+ if (sym->value == offset)
+ break;
+ } else {
+ /*
+ * Find the nearest symbol below this one.
+ */
+ sym = NULL;
+ for (sm = shead; sm; sm = sm->next)
+ if (sm->value <= offset && (!sym || sm->value > sym->value))
+ sym = sm;
+ }
+ if (!sym && exact) {
+ error (ERR_NONFATAL, "unable to find a suitable global symbol"
+ " for this reference");
+ return 0;
+ }
+
+ r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
+ sect->tail = &r->next;
+ r->next = NULL;
+
+ r->address = sect->len;
+ r->symbol = sym->symnum;
+ r->reltype = type | RELTYPE_SYMFLAG;
+ r->bytes = bytes;
+
+ sect->nrelocs++;
+
+ return offset - sym->value;
+}
+
+/*
+ * This routine deals with ..gotoff relocations. These _must_ refer
+ * to a symbol, due to a perversity of *BSD's PIC implementation,
+ * and it must be a non-global one as well; so we store `asym', the
+ * first nonglobal symbol defined in each section, and always work
+ * from that. Relocation type is always RELTYPE_GOTOFF.
+ *
+ * Return value is the adjusted value of `addr', having become an
+ * offset from the `asym' symbol rather than the section.
+ */
+static long aout_add_gotoff_reloc (struct Section *sect, long segment,
+ long offset, int bytes)
+{
+ struct Reloc *r;
+ struct Symbol *asym;
+
+ /*
+ * First look up the segment to find whether it's text, data,
+ * bss or an external symbol.
+ */
+ asym = NULL;
+ if (segment == stext.index)
+ asym = stext.asym;
+ else if (segment == sdata.index)
+ asym = sdata.asym;
+ else if (segment == sbss.index)
+ asym = sbss.asym;
+ if (!asym)
+ error (ERR_NONFATAL, "`..gotoff' relocations require a non-global"
+ " symbol in the section");
+
+ r = *sect->tail = nasm_malloc(sizeof(struct Reloc));
+ sect->tail = &r->next;
+ r->next = NULL;
+
+ r->address = sect->len;
+ r->symbol = asym->symnum;
+ r->reltype = RELTYPE_GOTOFF;
+ r->bytes = bytes;
+
+ sect->nrelocs++;
+
+ return offset - asym->value;
+}
+
+static void aout_out (long segto, void *data, unsigned long type,
+ long segment, long wrt)
+{
+ struct Section *s;
+ long realbytes = type & OUT_SIZMASK;
+ long addr;
+ unsigned char mydata[4], *p;
+
+ 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;
+ }
+
+ if (segto == stext.index)
+ s = &stext;
+ else if (segto == sdata.index)
+ s = &sdata;
+ else if (segto == sbss.index)
+ s = NULL;
+ else {
+ error(ERR_WARNING, "attempt to assemble code in"
+ " segment %d: defaulting to `.text'", segto);
+ s = &stext;
+ }
+
+ if (!s && type != OUT_RESERVE) {
+ error(ERR_WARNING, "attempt to initialise memory in the"
+ " BSS section: ignored");
+ if (type == OUT_REL2ADR)
+ realbytes = 2;
+ else if (type == OUT_REL4ADR)
+ realbytes = 4;
+ sbss.len += realbytes;
+ return;
+ }
+
+ if (type == OUT_RESERVE) {
+ if (s) {
+ error(ERR_WARNING, "uninitialised space declared in"
+ " %s section: zeroing",
+ (segto == stext.index ? "code" : "data"));
+ aout_sect_write (s, NULL, realbytes);
+ } else
+ sbss.len += realbytes;
+ } else if (type == OUT_RAWDATA) {
+ if (segment != NO_SEG)
+ error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
+ aout_sect_write (s, data, realbytes);
+ } else if (type == OUT_ADDRESS) {
+ addr = *(long *)data;
+ if (segment != NO_SEG) {
+ if (segment % 2) {
+ error(ERR_NONFATAL, "a.out format does not support"
+ " segment base references");
+ } else {
+ if (wrt == NO_SEG) {
+ aout_add_reloc (s, segment, RELTYPE_ABSOLUTE, realbytes);
+ } else if (!bsd) {
+ error (ERR_NONFATAL, "Linux a.out format does not support"
+ " any use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ } else if (wrt == aout_gotpc_sect+1) {
+ is_pic = 0x40;
+ aout_add_reloc (s, segment, RELTYPE_GOTPC, realbytes);
+ } else if (wrt == aout_gotoff_sect+1) {
+ is_pic = 0x40;
+ addr = aout_add_gotoff_reloc (s, segment,
+ addr, realbytes);
+ } else if (wrt == aout_got_sect+1) {
+ is_pic = 0x40;
+ addr = aout_add_gsym_reloc (s, segment, addr, RELTYPE_GOT,
+ realbytes, TRUE);
+ } else if (wrt == aout_sym_sect+1) {
+ addr = aout_add_gsym_reloc (s, segment, addr,
+ RELTYPE_ABSOLUTE, realbytes,
+ FALSE);
+ } else if (wrt == aout_plt_sect+1) {
+ is_pic = 0x40;
+ error(ERR_NONFATAL, "a.out format cannot produce non-PC-"
+ "relative PLT references");
+ } else {
+ error (ERR_NONFATAL, "a.out format does not support this"
+ " use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ }
+ }
+ }
+ p = mydata;
+ if (realbytes == 2)
+ WRITESHORT (p, addr);
+ else
+ WRITELONG (p, addr);
+ aout_sect_write (s, mydata, realbytes);
+ } else if (type == OUT_REL2ADR) {
+ if (segment == segto)
+ error(ERR_PANIC, "intra-segment OUT_REL2ADR");
+ if (segment != NO_SEG && segment % 2) {
+ error(ERR_NONFATAL, "a.out format does not support"
+ " segment base references");
+ } else {
+ if (wrt == NO_SEG) {
+ aout_add_reloc (s, segment, RELTYPE_RELATIVE, 2);
+ } else if (!bsd) {
+ error (ERR_NONFATAL, "Linux a.out format does not support"
+ " any use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ } else if (wrt == aout_plt_sect+1) {
+ is_pic = 0x40;
+ aout_add_reloc (s, segment, RELTYPE_PLT, 2);
+ } else if (wrt == aout_gotpc_sect+1 ||
+ wrt == aout_gotoff_sect+1 ||
+ wrt == aout_got_sect+1) {
+ error(ERR_NONFATAL, "a.out format cannot produce PC-"
+ "relative GOT references");
+ } else {
+ error (ERR_NONFATAL, "a.out format does not support this"
+ " use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ }
+ }
+ p = mydata;
+ WRITESHORT (p, *(long*)data-(realbytes + s->len));
+ aout_sect_write (s, mydata, 2L);
+ } else if (type == OUT_REL4ADR) {
+ if (segment == segto)
+ error(ERR_PANIC, "intra-segment OUT_REL4ADR");
+ if (segment != NO_SEG && segment % 2) {
+ error(ERR_NONFATAL, "a.out format does not support"
+ " segment base references");
+ } else {
+ if (wrt == NO_SEG) {
+ aout_add_reloc (s, segment, RELTYPE_RELATIVE, 4);
+ } else if (!bsd) {
+ error (ERR_NONFATAL, "Linux a.out format does not support"
+ " any use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ } else if (wrt == aout_plt_sect+1) {
+ is_pic = 0x40;
+ aout_add_reloc (s, segment, RELTYPE_PLT, 4);
+ } else if (wrt == aout_gotpc_sect+1 ||
+ wrt == aout_gotoff_sect+1 ||
+ wrt == aout_got_sect+1) {
+ error(ERR_NONFATAL, "a.out format cannot produce PC-"
+ "relative GOT references");
+ } else {
+ error (ERR_NONFATAL, "a.out format does not support this"
+ " use of WRT");
+ wrt = NO_SEG; /* we can at least _try_ to continue */
+ }
+ }
+ p = mydata;
+ WRITELONG (p, *(long*)data-(realbytes + s->len));
+ aout_sect_write (s, mydata, 4L);
+ }
+}
+
+static void aout_pad_sections(void)
+{
+ static unsigned char pad[] = { 0x90, 0x90, 0x90, 0x90 };
+ /*
+ * Pad each of the text and data sections with NOPs until their
+ * length is a multiple of four. (NOP == 0x90.) Also increase
+ * the length of the BSS section similarly.
+ */
+ aout_sect_write (&stext, pad, (-(long)stext.len) & 3);
+ aout_sect_write (&sdata, pad, (-(long)sdata.len) & 3);
+ sbss.len = (sbss.len + 3) & ~3;
+}
+
+/*
+ * a.out files have the curious property that all references to
+ * things in the data or bss sections are done by addresses which
+ * are actually relative to the start of the _text_ section, in the
+ * _file_. (No relation to what happens after linking. No idea why
+ * this should be so. It's very strange.) So we have to go through
+ * the relocation table, _after_ the final size of each section is
+ * known, and fix up the relocations pointed to.
+ */
+static void aout_fixup_relocs(struct Section *sect)
+{
+ struct Reloc *r;
+
+ saa_rewind (sect->data);
+ for (r = sect->head; r; r = r->next) {
+ unsigned char *p, *q, blk[4];
+ long l;
+
+ saa_fread (sect->data, r->address, blk, (long)r->bytes);
+ p = q = blk;
+ l = *p++;
+ if (r->bytes > 1) {
+ l += ((long)*p++) << 8;
+ if (r->bytes == 4) {
+ l += ((long)*p++) << 16;
+ l += ((long)*p++) << 24;
+ }
+ }
+ if (r->symbol == -SECT_DATA)
+ l += stext.len;
+ else if (r->symbol == -SECT_BSS)
+ l += stext.len + sdata.len;
+ if (r->bytes == 4)
+ WRITELONG(q, l);
+ else if (r->bytes == 2)
+ WRITESHORT(q, l);
+ else
+ *q++ = l & 0xFF;
+ saa_fwrite (sect->data, r->address, blk, (long)r->bytes);
+ }
+}
+
+static void aout_write(void)
+{
+ /*
+ * Emit the a.out header.
+ */
+ /* OMAGIC, M_386 or MID_I386, no flags */
+ fwritelong (bsd ? 0x07018600 | is_pic : 0x640107L, aoutfp);
+ fwritelong (stext.len, aoutfp);
+ fwritelong (sdata.len, aoutfp);
+ fwritelong (sbss.len, aoutfp);
+ fwritelong (nsyms * 12, aoutfp); /* length of symbol table */
+ fwritelong (0L, aoutfp); /* object files have no entry point */
+ fwritelong (stext.nrelocs * 8, aoutfp); /* size of text relocs */
+ fwritelong (sdata.nrelocs * 8, aoutfp); /* size of data relocs */
+
+ /*
+ * Write out the code section and the data section.
+ */
+ saa_fpwrite (stext.data, aoutfp);
+ saa_fpwrite (sdata.data, aoutfp);
+
+ /*
+ * Write out the relocations.
+ */
+ aout_write_relocs (stext.head);
+ aout_write_relocs (sdata.head);
+
+ /*
+ * Write the symbol table.
+ */
+ aout_write_syms ();
+
+ /*
+ * And the string table.
+ */
+ fwritelong (strslen+4, aoutfp); /* length includes length count */
+ saa_fpwrite (strs, aoutfp);
+}
+
+static void aout_write_relocs (struct Reloc *r)
+{
+ while (r) {
+ unsigned long word2;
+
+ fwritelong (r->address, aoutfp);
+
+ if (r->symbol >= 0)
+ word2 = r->symbol;
+ else
+ word2 = -r->symbol;
+ word2 |= r->reltype << 24;
+ word2 |= (r->bytes == 1 ? 0 :
+ r->bytes == 2 ? 0x2000000L : 0x4000000L);
+ fwritelong (word2, aoutfp);
+
+ r = r->next;
+ }
+}
+
+static void aout_write_syms (void)
+{
+ unsigned long i;
+
+ saa_rewind (syms);
+ for (i = 0; i < nsyms; i++) {
+ struct Symbol *sym = saa_rstruct(syms);
+ fwritelong (sym->strpos, aoutfp);
+ fwritelong ((long)sym->type & ~SYM_WITH_SIZE, aoutfp);
+ /*
+ * Fix up the symbol value now we know the final section
+ * sizes.
+ */
+ if ((sym->type & SECT_MASK) == SECT_DATA)
+ sym->value += stext.len;
+ if ((sym->type & SECT_MASK) == SECT_BSS)
+ sym->value += stext.len + sdata.len;
+ fwritelong (sym->value, aoutfp);
+ /*
+ * Output a size record if necessary.
+ */
+ if (sym->type & SYM_WITH_SIZE) {
+ fwritelong(sym->strpos, aoutfp);
+ fwritelong(0x0DL, aoutfp); /* special value: means size */
+ fwritelong(sym->size, aoutfp);
+ i++; /* use up another of `nsyms' */
+ }
+ }
+}
+
+static void aout_sect_write (struct Section *sect,
+ unsigned char *data, unsigned long len)
+{
+ saa_wbytes (sect->data, data, len);
+ sect->len += len;
+}
+
+static long aout_segbase (long segment)
+{
+ return segment;
+}
+
+static int aout_directive (char *directive, char *value, int pass)
+{
+ return 0;
+}
+
+static void aout_filename (char *inname, char *outname, efunc error)
+{
+ standard_extension (inname, outname, ".o", error);
+}
+
+static char *aout_stdmac[] = {
+ "%define __SECT__ [section .text]",
+ "%macro __NASM_CDecl__ 1",
+ "%endmacro",
+ NULL
+};
+
+static int aout_set_info(enum geninfo type, char **val)
+{
+ return 0;
+}
+#endif /* OF_AOUT || OF_AOUTB */
+
+#ifdef OF_AOUT
+
+struct ofmt of_aout = {
+ "Linux a.out object files",
+ "aout",
+ NULL,
+ null_debug_arr,
+ &null_debug_form,
+ aout_stdmac,
+ aout_init,
+ aout_set_info,
+ aout_out,
+ aout_deflabel,
+ aout_section_names,
+ aout_segbase,
+ aout_directive,
+ aout_filename,
+ aout_cleanup
+};
+
+#endif
+
+#ifdef OF_AOUTB
+
+struct ofmt of_aoutb = {
+ "NetBSD/FreeBSD a.out object files",
+ "aoutb",
+ NULL,
+ null_debug_arr,
+ &null_debug_form,
+ aout_stdmac,
+ aoutb_init,
+ aout_set_info,
+ aout_out,
+ aout_deflabel,
+ aout_section_names,
+ aout_segbase,
+ aout_directive,
+ aout_filename,
+ aout_cleanup
+};
+
+#endif