1 /* BFD back-end for Intel 386 COFF files.
2 Copyright 1990, 1991, 1992, 1993, 1994 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. */
25 #include "coff/i386.h"
26 #include "coff/internal.h"
29 static bfd_reloc_status_type coff_i386_reloc
30 PARAMS ((bfd
*, arelent
*, asymbol
*, PTR
, asection
*, bfd
*, char **));
31 static const struct reloc_howto_struct
*coff_i386_rtype_to_howto
32 PARAMS ((bfd
*, asection
*, struct internal_reloc
*,
33 struct coff_link_hash_entry
*, struct internal_syment
*,
36 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
38 /* The page size is a guess based on ELF. */
39 #define COFF_PAGE_SIZE 0x1000
41 /* For some reason when using i386 COFF the value stored in the .text
42 section for a reference to a common symbol is the value itself plus
43 any desired offset. Ian Taylor, Cygnus Support. */
45 /* If we are producing relocateable output, we need to do some
46 adjustments to the object file that are not done by the
47 bfd_perform_relocation function. This function is called by every
48 reloc type to make any required adjustments. */
50 static bfd_reloc_status_type
51 coff_i386_reloc (abfd
, reloc_entry
, symbol
, data
, input_section
, output_bfd
,
57 asection
*input_section
;
63 if (output_bfd
== (bfd
*) NULL
)
64 return bfd_reloc_continue
;
66 if (bfd_is_com_section (symbol
->section
))
68 /* We are relocating a common symbol. The current value in the
69 object file is ORIG + OFFSET, where ORIG is the value of the
70 common symbol as seen by the object file when it was compiled
71 (this may be zero if the symbol was undefined) and OFFSET is
72 the offset into the common symbol (normally zero, but may be
73 non-zero when referring to a field in a common structure).
74 ORIG is the negative of reloc_entry->addend, which is set by
75 the CALC_ADDEND macro below. We want to replace the value in
76 the object file with NEW + OFFSET, where NEW is the value of
77 the common symbol which we are going to put in the final
78 object file. NEW is symbol->value. */
79 diff
= symbol
->value
+ reloc_entry
->addend
;
83 /* For some reason bfd_perform_relocation always effectively
84 ignores the addend for a COFF target when producing
85 relocateable output. This seems to be always wrong for 386
86 COFF, so we handle the addend here instead. */
87 diff
= reloc_entry
->addend
;
91 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
95 reloc_howto_type
*howto
= reloc_entry
->howto
;
96 unsigned char *addr
= (unsigned char *) data
+ reloc_entry
->address
;
102 char x
= bfd_get_8 (abfd
, addr
);
104 bfd_put_8 (abfd
, x
, addr
);
110 short x
= bfd_get_16 (abfd
, addr
);
112 bfd_put_16 (abfd
, x
, addr
);
118 long x
= bfd_get_32 (abfd
, addr
);
120 bfd_put_32 (abfd
, x
, addr
);
129 /* Now let bfd_perform_relocation finish everything up. */
130 return bfd_reloc_continue
;
133 static reloc_howto_type howto_table
[] =
141 HOWTO (R_DIR32
, /* type */
143 2, /* size (0 = byte, 1 = short, 2 = long) */
145 false, /* pc_relative */
147 complain_overflow_bitfield
, /* complain_on_overflow */
148 coff_i386_reloc
, /* special_function */
150 true, /* partial_inplace */
151 0xffffffff, /* src_mask */
152 0xffffffff, /* dst_mask */
153 false), /* pcrel_offset */
162 HOWTO (R_RELBYTE
, /* type */
164 0, /* size (0 = byte, 1 = short, 2 = long) */
166 false, /* pc_relative */
168 complain_overflow_bitfield
, /* complain_on_overflow */
169 coff_i386_reloc
, /* special_function */
171 true, /* partial_inplace */
172 0x000000ff, /* src_mask */
173 0x000000ff, /* dst_mask */
174 false), /* pcrel_offset */
175 HOWTO (R_RELWORD
, /* type */
177 1, /* size (0 = byte, 1 = short, 2 = long) */
179 false, /* pc_relative */
181 complain_overflow_bitfield
, /* complain_on_overflow */
182 coff_i386_reloc
, /* special_function */
184 true, /* partial_inplace */
185 0x0000ffff, /* src_mask */
186 0x0000ffff, /* dst_mask */
187 false), /* pcrel_offset */
188 HOWTO (R_RELLONG
, /* type */
190 2, /* 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 0xffffffff, /* src_mask */
199 0xffffffff, /* dst_mask */
200 false), /* pcrel_offset */
201 HOWTO (R_PCRBYTE
, /* type */
203 0, /* size (0 = byte, 1 = short, 2 = long) */
205 true, /* pc_relative */
207 complain_overflow_signed
, /* complain_on_overflow */
208 coff_i386_reloc
, /* special_function */
210 true, /* partial_inplace */
211 0x000000ff, /* src_mask */
212 0x000000ff, /* dst_mask */
213 false), /* pcrel_offset */
214 HOWTO (R_PCRWORD
, /* type */
216 1, /* size (0 = byte, 1 = short, 2 = long) */
218 true, /* pc_relative */
220 complain_overflow_signed
, /* complain_on_overflow */
221 coff_i386_reloc
, /* special_function */
223 true, /* partial_inplace */
224 0x0000ffff, /* src_mask */
225 0x0000ffff, /* dst_mask */
226 false), /* pcrel_offset */
227 HOWTO (R_PCRLONG
, /* type */
229 2, /* 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 0xffffffff, /* src_mask */
238 0xffffffff, /* dst_mask */
239 false) /* pcrel_offset */
242 /* Turn a howto into a reloc nunmber */
244 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
245 #define BADMAG(x) I386BADMAG(x)
246 #define I386 1 /* Customize coffcode.h */
248 #define RTYPE2HOWTO(cache_ptr, dst) \
249 (cache_ptr)->howto = howto_table + (dst)->r_type;
251 /* On SCO Unix 3.2.2 the native assembler generates two .data
252 sections. We handle that by renaming the second one to .data2. It
253 does no harm to do this for any 386 COFF target. */
254 #define TWO_DATA_SECS
256 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
257 library. On some other COFF targets STYP_BSS is normally
259 #define BSS_NOLOAD_IS_SHARED_LIBRARY
261 /* Compute the addend of a reloc. If the reloc is to a common symbol,
262 the object file contains the value of the common symbol. By the
263 time this is called, the linker may be using a different symbol
264 from a different object file with a different value. Therefore, we
265 hack wildly to locate the original symbol from this file so that we
266 can make the correct adjustment. This macro sets coffsym to the
267 symbol from the original file, and uses it to set the addend value
268 correctly. If this is not a common symbol, the usual addend
269 calculation is done, except that an additional tweak is needed for
271 FIXME: This macro refers to symbols and asect; these are from the
272 calling function, not the macro arguments. */
274 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
276 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
277 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
278 coffsym = (obj_symbols (abfd) \
279 + (cache_ptr->sym_ptr_ptr - symbols)); \
281 coffsym = coff_symbol_from (abfd, ptr); \
282 if (coffsym != (coff_symbol_type *) NULL \
283 && coffsym->native->u.syment.n_scnum == 0) \
284 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
285 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
286 && ptr->section != (asection *) NULL) \
287 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
289 cache_ptr->addend = 0; \
290 if (ptr && howto_table[reloc.r_type].pc_relative) \
291 cache_ptr->addend += asect->vma; \
294 /* We use the special COFF backend linker. */
295 #define coff_relocate_section _bfd_coff_generic_relocate_section
297 static const struct reloc_howto_struct
*
298 coff_i386_rtype_to_howto (abfd
, sec
, rel
, h
, sym
, addendp
)
301 struct internal_reloc
*rel
;
302 struct coff_link_hash_entry
*h
;
303 struct internal_syment
*sym
;
306 const struct reloc_howto_struct
*howto
;
308 howto
= howto_table
+ rel
->r_type
;
310 if (howto
->pc_relative
)
311 *addendp
+= sec
->vma
;
313 if (sym
!= NULL
&& sym
->n_scnum
== 0 && sym
->n_value
!= 0)
315 /* This is a common symbol. The section contents include the
316 size (sym->n_value) as an addend. The relocate_section
317 function will be adding in the final value of the symbol. We
318 need to subtract out the current size in order to get the
320 BFD_ASSERT (h
!= NULL
);
321 *addendp
-= sym
->n_value
;
324 /* If the output symbol is common (in which case this must be a
325 relocateable link), we need to add in the final size of the
327 if (h
!= NULL
&& h
->root
.type
== bfd_link_hash_common
)
328 *addendp
+= h
->root
.u
.c
.size
;
333 #define coff_rtype_to_howto coff_i386_rtype_to_howto
335 #include "coffcode.h"
337 static const bfd_target
*
341 return coff_object_p(a
);
354 "coff-i386", /* name */
356 bfd_target_coff_flavour
,
357 false, /* data byte order is little */
358 false, /* header byte order is little */
360 (HAS_RELOC
| EXEC_P
| /* object flags */
361 HAS_LINENO
| HAS_DEBUG
|
362 HAS_SYMS
| HAS_LOCALS
| WP_TEXT
| D_PAGED
),
364 (SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_RELOC
), /* section flags */
365 #ifdef TARGET_UNDERSCORE
366 TARGET_UNDERSCORE
, /* leading underscore */
368 0, /* leading underscore */
370 '/', /* ar_pad_char */
371 15, /* ar_max_namelen */
373 2, /* minimum alignment power */
374 bfd_getl64
, bfd_getl_signed_64
, bfd_putl64
,
375 bfd_getl32
, bfd_getl_signed_32
, bfd_putl32
,
376 bfd_getl16
, bfd_getl_signed_16
, bfd_putl16
, /* data */
377 bfd_getl64
, bfd_getl_signed_64
, bfd_putl64
,
378 bfd_getl32
, bfd_getl_signed_32
, bfd_putl32
,
379 bfd_getl16
, bfd_getl_signed_16
, bfd_putl16
, /* hdrs */
381 /* Note that we allow an object file to be treated as a core file as well. */
382 {_bfd_dummy_target
, i3coff_object_p
, /* bfd_check_format */
383 bfd_generic_archive_p
, i3coff_object_p
},
384 {bfd_false
, coff_mkobject
, _bfd_generic_mkarchive
, /* bfd_set_format */
386 {bfd_false
, coff_write_object_contents
, /* bfd_write_contents */
387 _bfd_write_archive_contents
, bfd_false
},
389 BFD_JUMP_TABLE_GENERIC (coff
),
390 BFD_JUMP_TABLE_COPY (coff
),
391 BFD_JUMP_TABLE_CORE (_bfd_nocore
),
392 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff
),
393 BFD_JUMP_TABLE_SYMBOLS (coff
),
394 BFD_JUMP_TABLE_RELOCS (coff
),
395 BFD_JUMP_TABLE_WRITE (coff
),
396 BFD_JUMP_TABLE_LINK (coff
),
397 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic
),