1 /* BFD back-end for Intel 386 COFF files.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
3 Written by Cygnus Support.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
26 #include "coff/i386.h"
28 #include "coff/internal.h"
36 static bfd_reloc_status_type coff_i386_reloc
37 PARAMS ((bfd
*, arelent
*, asymbol
*, PTR
, asection
*, bfd
*, char **));
38 static reloc_howto_type
*coff_i386_rtype_to_howto
39 PARAMS ((bfd
*, asection
*, struct internal_reloc
*,
40 struct coff_link_hash_entry
*, struct internal_syment
*,
44 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
45 /* The page size is a guess based on ELF. */
46 #define COFF_PAGE_SIZE 0x1000
48 /* For some reason when using i386 COFF the value stored in the .text
49 section for a reference to a common symbol is the value itself plus
50 any desired offset. Ian Taylor, Cygnus Support. */
52 /* If we are producing relocateable output, we need to do some
53 adjustments to the object file that are not done by the
54 bfd_perform_relocation function. This function is called by every
55 reloc type to make any required adjustments. */
57 static bfd_reloc_status_type
58 coff_i386_reloc (abfd
, reloc_entry
, symbol
, data
, input_section
, output_bfd
,
64 asection
*input_section
;
70 if (output_bfd
== (bfd
*) NULL
)
71 return bfd_reloc_continue
;
73 if (bfd_is_com_section (symbol
->section
))
75 /* We are relocating a common symbol. The current value in the
76 object file is ORIG + OFFSET, where ORIG is the value of the
77 common symbol as seen by the object file when it was compiled
78 (this may be zero if the symbol was undefined) and OFFSET is
79 the offset into the common symbol (normally zero, but may be
80 non-zero when referring to a field in a common structure).
81 ORIG is the negative of reloc_entry->addend, which is set by
82 the CALC_ADDEND macro below. We want to replace the value in
83 the object file with NEW + OFFSET, where NEW is the value of
84 the common symbol which we are going to put in the final
85 object file. NEW is symbol->value. */
86 diff
= symbol
->value
+ reloc_entry
->addend
;
90 /* For some reason bfd_perform_relocation always effectively
91 ignores the addend for a COFF target when producing
92 relocateable output. This seems to be always wrong for 386
93 COFF, so we handle the addend here instead. */
94 diff
= reloc_entry
->addend
;
98 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
102 reloc_howto_type
*howto
= reloc_entry
->howto
;
103 unsigned char *addr
= (unsigned char *) data
+ reloc_entry
->address
;
109 char x
= bfd_get_8 (abfd
, addr
);
111 bfd_put_8 (abfd
, x
, addr
);
117 short x
= bfd_get_16 (abfd
, addr
);
119 bfd_put_16 (abfd
, x
, addr
);
125 long x
= bfd_get_32 (abfd
, addr
);
127 bfd_put_32 (abfd
, x
, addr
);
136 /* Now let bfd_perform_relocation finish everything up. */
137 return bfd_reloc_continue
;
143 #define PCRELOFFSET false
146 static reloc_howto_type howto_table
[] =
154 HOWTO (R_DIR32
, /* type */
156 2, /* size (0 = byte, 1 = short, 2 = long) */
158 false, /* pc_relative */
160 complain_overflow_bitfield
, /* complain_on_overflow */
161 coff_i386_reloc
, /* special_function */
163 true, /* partial_inplace */
164 0xffffffff, /* src_mask */
165 0xffffffff, /* dst_mask */
166 true), /* pcrel_offset */
170 2, /* size (0 = byte, 1 = short, 2 = long) */
172 false, /* pc_relative */
174 complain_overflow_bitfield
, /* complain_on_overflow */
175 coff_i386_reloc
, /* special_function */
177 true, /* partial_inplace */
178 0xffffffff, /* src_mask */
179 0xffffffff, /* dst_mask */
180 false), /* pcrel_offset */
188 HOWTO (R_RELBYTE
, /* type */
190 0, /* size (0 = byte, 1 = short, 2 = long) */
192 false, /* pc_relative */
194 complain_overflow_bitfield
, /* complain_on_overflow */
195 coff_i386_reloc
, /* special_function */
197 true, /* partial_inplace */
198 0x000000ff, /* src_mask */
199 0x000000ff, /* dst_mask */
200 PCRELOFFSET
), /* pcrel_offset */
201 HOWTO (R_RELWORD
, /* type */
203 1, /* size (0 = byte, 1 = short, 2 = long) */
205 false, /* pc_relative */
207 complain_overflow_bitfield
, /* complain_on_overflow */
208 coff_i386_reloc
, /* special_function */
210 true, /* partial_inplace */
211 0x0000ffff, /* src_mask */
212 0x0000ffff, /* dst_mask */
213 PCRELOFFSET
), /* pcrel_offset */
214 HOWTO (R_RELLONG
, /* type */
216 2, /* size (0 = byte, 1 = short, 2 = long) */
218 false, /* pc_relative */
220 complain_overflow_bitfield
, /* complain_on_overflow */
221 coff_i386_reloc
, /* special_function */
223 true, /* partial_inplace */
224 0xffffffff, /* src_mask */
225 0xffffffff, /* dst_mask */
226 PCRELOFFSET
), /* pcrel_offset */
227 HOWTO (R_PCRBYTE
, /* type */
229 0, /* size (0 = byte, 1 = short, 2 = long) */
231 true, /* pc_relative */
233 complain_overflow_signed
, /* complain_on_overflow */
234 coff_i386_reloc
, /* special_function */
236 true, /* partial_inplace */
237 0x000000ff, /* src_mask */
238 0x000000ff, /* dst_mask */
239 PCRELOFFSET
), /* pcrel_offset */
240 HOWTO (R_PCRWORD
, /* type */
242 1, /* size (0 = byte, 1 = short, 2 = long) */
244 true, /* pc_relative */
246 complain_overflow_signed
, /* complain_on_overflow */
247 coff_i386_reloc
, /* special_function */
249 true, /* partial_inplace */
250 0x0000ffff, /* src_mask */
251 0x0000ffff, /* dst_mask */
252 PCRELOFFSET
), /* pcrel_offset */
253 HOWTO (R_PCRLONG
, /* type */
255 2, /* size (0 = byte, 1 = short, 2 = long) */
257 true, /* pc_relative */
259 complain_overflow_signed
, /* complain_on_overflow */
260 coff_i386_reloc
, /* special_function */
262 true, /* partial_inplace */
263 0xffffffff, /* src_mask */
264 0xffffffff, /* dst_mask */
265 PCRELOFFSET
) /* pcrel_offset */
268 /* Turn a howto into a reloc nunmber */
270 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
271 #define BADMAG(x) I386BADMAG(x)
272 #define I386 1 /* Customize coffcode.h */
274 #define RTYPE2HOWTO(cache_ptr, dst) \
275 (cache_ptr)->howto = howto_table + (dst)->r_type;
277 /* On SCO Unix 3.2.2 the native assembler generates two .data
278 sections. We handle that by renaming the second one to .data2. It
279 does no harm to do this for any 386 COFF target. */
280 #define TWO_DATA_SECS
282 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
283 library. On some other COFF targets STYP_BSS is normally
285 #define BSS_NOLOAD_IS_SHARED_LIBRARY
287 /* Compute the addend of a reloc. If the reloc is to a common symbol,
288 the object file contains the value of the common symbol. By the
289 time this is called, the linker may be using a different symbol
290 from a different object file with a different value. Therefore, we
291 hack wildly to locate the original symbol from this file so that we
292 can make the correct adjustment. This macro sets coffsym to the
293 symbol from the original file, and uses it to set the addend value
294 correctly. If this is not a common symbol, the usual addend
295 calculation is done, except that an additional tweak is needed for
297 FIXME: This macro refers to symbols and asect; these are from the
298 calling function, not the macro arguments. */
300 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
302 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
303 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
304 coffsym = (obj_symbols (abfd) \
305 + (cache_ptr->sym_ptr_ptr - symbols)); \
307 coffsym = coff_symbol_from (abfd, ptr); \
308 if (coffsym != (coff_symbol_type *) NULL \
309 && coffsym->native->u.syment.n_scnum == 0) \
310 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
311 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
312 && ptr->section != (asection *) NULL) \
313 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
315 cache_ptr->addend = 0; \
316 if (ptr && howto_table[reloc.r_type].pc_relative) \
317 cache_ptr->addend += asect->vma; \
320 /* We use the special COFF backend linker. */
321 #define coff_relocate_section _bfd_coff_generic_relocate_section
323 static reloc_howto_type
*
324 coff_i386_rtype_to_howto (abfd
, sec
, rel
, h
, sym
, addendp
)
327 struct internal_reloc
*rel
;
328 struct coff_link_hash_entry
*h
;
329 struct internal_syment
*sym
;
333 reloc_howto_type
*howto
;
335 howto
= howto_table
+ rel
->r_type
;
341 if (howto
->pc_relative
)
342 *addendp
+= sec
->vma
;
344 if (sym
!= NULL
&& sym
->n_scnum
== 0 && sym
->n_value
!= 0)
346 /* This is a common symbol. The section contents include the
347 size (sym->n_value) as an addend. The relocate_section
348 function will be adding in the final value of the symbol. We
349 need to subtract out the current size in order to get the
352 BFD_ASSERT (h
!= NULL
);
356 /* I think we *do* want to bypass this. If we don't, I have seen some data
357 parameters get the wrong relcation address. If I link two versions
358 with and without this section bypassed and then do a binary comparison,
359 the addresses which are different can be looked up in the map. The
360 case in which this section has been bypassed has addresses which correspond
361 to values I can find in the map */
362 *addendp
-= sym
->n_value
;
366 /* If the output symbol is common (in which case this must be a
367 relocateable link), we need to add in the final size of the
369 if (h
!= NULL
&& h
->root
.type
== bfd_link_hash_common
)
370 *addendp
+= h
->root
.u
.c
.size
;
374 if (howto
->pc_relative
)
381 #define coff_rtype_to_howto coff_i386_rtype_to_howto
383 #include "coffcode.h"
385 static const bfd_target
*
389 return coff_object_p(a
);
402 "coff-i386", /* name */
404 bfd_target_coff_flavour
,
405 false, /* data byte order is little */
406 false, /* header byte order is little */
408 (HAS_RELOC
| EXEC_P
| /* object flags */
409 HAS_LINENO
| HAS_DEBUG
|
410 HAS_SYMS
| HAS_LOCALS
| WP_TEXT
| D_PAGED
),
412 (SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_RELOC
), /* section flags */
413 #ifdef TARGET_UNDERSCORE
414 TARGET_UNDERSCORE
, /* leading underscore */
416 0, /* leading underscore */
418 '/', /* ar_pad_char */
419 15, /* ar_max_namelen */
421 2, /* minimum alignment power */
422 bfd_getl64
, bfd_getl_signed_64
, bfd_putl64
,
423 bfd_getl32
, bfd_getl_signed_32
, bfd_putl32
,
424 bfd_getl16
, bfd_getl_signed_16
, bfd_putl16
, /* data */
425 bfd_getl64
, bfd_getl_signed_64
, bfd_putl64
,
426 bfd_getl32
, bfd_getl_signed_32
, bfd_putl32
,
427 bfd_getl16
, bfd_getl_signed_16
, bfd_putl16
, /* hdrs */
429 /* Note that we allow an object file to be treated as a core file as well. */
430 {_bfd_dummy_target
, i3coff_object_p
, /* bfd_check_format */
431 bfd_generic_archive_p
, i3coff_object_p
},
432 {bfd_false
, coff_mkobject
, _bfd_generic_mkarchive
, /* bfd_set_format */
434 {bfd_false
, coff_write_object_contents
, /* bfd_write_contents */
435 _bfd_write_archive_contents
, bfd_false
},
437 BFD_JUMP_TABLE_GENERIC (coff
),
438 BFD_JUMP_TABLE_COPY (coff
),
439 BFD_JUMP_TABLE_CORE (_bfd_nocore
),
440 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff
),
441 BFD_JUMP_TABLE_SYMBOLS (coff
),
442 BFD_JUMP_TABLE_RELOCS (coff
),
443 BFD_JUMP_TABLE_WRITE (coff
),
444 BFD_JUMP_TABLE_LINK (coff
),
445 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic
),