1 /* BFD back-end for Intel 386 COFF files.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2007
4 Free Software Foundation, Inc.
5 Written by Cygnus Support.
7 This file is part of BFD, the Binary File Descriptor library.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 MA 02110-1301, USA. */
28 #include "coff/i386.h"
30 #include "coff/internal.h"
37 #include "coff/go32exe.h"
42 static bfd_reloc_status_type coff_i386_reloc
43 PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
44 static reloc_howto_type *coff_i386_rtype_to_howto
45 PARAMS ((bfd *, asection *, struct internal_reloc *,
46 struct coff_link_hash_entry *, struct internal_syment *,
48 static reloc_howto_type *coff_i386_reloc_type_lookup
49 PARAMS ((bfd *, bfd_reloc_code_real_type));
51 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
52 /* The page size is a guess based on ELF. */
54 #define COFF_PAGE_SIZE 0x1000
56 /* For some reason when using i386 COFF the value stored in the .text
57 section for a reference to a common symbol is the value itself plus
58 any desired offset. Ian Taylor, Cygnus Support. */
60 /* If we are producing relocatable output, we need to do some
61 adjustments to the object file that are not done by the
62 bfd_perform_relocation function. This function is called by every
63 reloc type to make any required adjustments. */
65 static bfd_reloc_status_type
66 coff_i386_reloc (abfd, reloc_entry, symbol, data, input_section, output_bfd,
72 asection *input_section ATTRIBUTE_UNUSED;
74 char **error_message ATTRIBUTE_UNUSED;
79 if (output_bfd == (bfd *) NULL)
80 return bfd_reloc_continue;
83 if (bfd_is_com_section (symbol->section))
86 /* We are relocating a common symbol. The current value in the
87 object file is ORIG + OFFSET, where ORIG is the value of the
88 common symbol as seen by the object file when it was compiled
89 (this may be zero if the symbol was undefined) and OFFSET is
90 the offset into the common symbol (normally zero, but may be
91 non-zero when referring to a field in a common structure).
92 ORIG is the negative of reloc_entry->addend, which is set by
93 the CALC_ADDEND macro below. We want to replace the value in
94 the object file with NEW + OFFSET, where NEW is the value of
95 the common symbol which we are going to put in the final
96 object file. NEW is symbol->value. */
97 diff = symbol->value + reloc_entry->addend;
99 /* In PE mode, we do not offset the common symbol. */
100 diff = reloc_entry->addend;
105 /* For some reason bfd_perform_relocation always effectively
106 ignores the addend for a COFF target when producing
107 relocatable output. This seems to be always wrong for 386
108 COFF, so we handle the addend here instead. */
110 if (output_bfd == (bfd *) NULL)
112 reloc_howto_type *howto = reloc_entry->howto;
114 /* Although PC relative relocations are very similar between
115 PE and non-PE formats, but they are off by 1 << howto->size
116 bytes. For the external relocation, PE is very different
117 from others. See md_apply_fix3 () in gas/config/tc-i386.c.
118 When we link PE and non-PE object files together to
119 generate a non-PE executable, we have to compensate it
121 if (howto->pc_relative && howto->pcrel_offset)
122 diff = -(1 << howto->size);
123 else if (symbol->flags & BSF_WEAK)
124 diff = reloc_entry->addend - symbol->value;
126 diff = -reloc_entry->addend;
130 diff = reloc_entry->addend;
134 /* FIXME: How should this case be handled? */
135 if (reloc_entry->howto->type == R_IMAGEBASE
136 && output_bfd != NULL
137 && bfd_get_flavour(output_bfd) == bfd_target_coff_flavour)
138 diff -= pe_data (output_bfd)->pe_opthdr.ImageBase;
142 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
146 reloc_howto_type *howto = reloc_entry->howto;
147 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
153 char x = bfd_get_8 (abfd, addr);
155 bfd_put_8 (abfd, x, addr);
161 short x = bfd_get_16 (abfd, addr);
163 bfd_put_16 (abfd, (bfd_vma) x, addr);
169 long x = bfd_get_32 (abfd, addr);
171 bfd_put_32 (abfd, (bfd_vma) x, addr);
180 /* Now let bfd_perform_relocation finish everything up. */
181 return bfd_reloc_continue;
185 /* Return TRUE if this relocation should appear in the output .reloc
188 static bfd_boolean in_reloc_p PARAMS ((bfd *, reloc_howto_type *));
190 static bfd_boolean in_reloc_p (abfd, howto)
191 bfd * abfd ATTRIBUTE_UNUSED;
192 reloc_howto_type *howto;
194 return ! howto->pc_relative && howto->type != R_IMAGEBASE;
196 #endif /* COFF_WITH_PE */
199 #define PCRELOFFSET FALSE
202 static reloc_howto_type howto_table[] =
210 HOWTO (R_DIR32, /* type */
212 2, /* size (0 = byte, 1 = short, 2 = long) */
214 FALSE, /* pc_relative */
216 complain_overflow_bitfield, /* complain_on_overflow */
217 coff_i386_reloc, /* special_function */
219 TRUE, /* partial_inplace */
220 0xffffffff, /* src_mask */
221 0xffffffff, /* dst_mask */
222 TRUE), /* pcrel_offset */
223 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
224 HOWTO (R_IMAGEBASE, /* type */
226 2, /* size (0 = byte, 1 = short, 2 = long) */
228 FALSE, /* pc_relative */
230 complain_overflow_bitfield, /* complain_on_overflow */
231 coff_i386_reloc, /* special_function */
233 TRUE, /* partial_inplace */
234 0xffffffff, /* src_mask */
235 0xffffffff, /* dst_mask */
236 FALSE), /* pcrel_offset */
241 /* 32-bit longword section relative relocation (013). */
242 HOWTO (R_SECREL32, /* type */
244 2, /* size (0 = byte, 1 = short, 2 = long) */
246 FALSE, /* pc_relative */
248 complain_overflow_bitfield, /* complain_on_overflow */
249 coff_i386_reloc, /* special_function */
250 "secrel32", /* name */
251 TRUE, /* partial_inplace */
252 0xffffffff, /* src_mask */
253 0xffffffff, /* dst_mask */
254 TRUE), /* pcrel_offset */
261 /* Byte relocation (017). */
262 HOWTO (R_RELBYTE, /* type */
264 0, /* size (0 = byte, 1 = short, 2 = long) */
266 FALSE, /* pc_relative */
268 complain_overflow_bitfield, /* complain_on_overflow */
269 coff_i386_reloc, /* special_function */
271 TRUE, /* partial_inplace */
272 0x000000ff, /* src_mask */
273 0x000000ff, /* dst_mask */
274 PCRELOFFSET), /* pcrel_offset */
275 /* 16-bit word relocation (020). */
276 HOWTO (R_RELWORD, /* type */
278 1, /* size (0 = byte, 1 = short, 2 = long) */
280 FALSE, /* pc_relative */
282 complain_overflow_bitfield, /* complain_on_overflow */
283 coff_i386_reloc, /* special_function */
285 TRUE, /* partial_inplace */
286 0x0000ffff, /* src_mask */
287 0x0000ffff, /* dst_mask */
288 PCRELOFFSET), /* pcrel_offset */
289 /* 32-bit longword relocation (021). */
290 HOWTO (R_RELLONG, /* type */
292 2, /* size (0 = byte, 1 = short, 2 = long) */
294 FALSE, /* pc_relative */
296 complain_overflow_bitfield, /* complain_on_overflow */
297 coff_i386_reloc, /* special_function */
299 TRUE, /* partial_inplace */
300 0xffffffff, /* src_mask */
301 0xffffffff, /* dst_mask */
302 PCRELOFFSET), /* pcrel_offset */
303 /* Byte PC relative relocation (022). */
304 HOWTO (R_PCRBYTE, /* type */
306 0, /* size (0 = byte, 1 = short, 2 = long) */
308 TRUE, /* pc_relative */
310 complain_overflow_signed, /* complain_on_overflow */
311 coff_i386_reloc, /* special_function */
313 TRUE, /* partial_inplace */
314 0x000000ff, /* src_mask */
315 0x000000ff, /* dst_mask */
316 PCRELOFFSET), /* pcrel_offset */
317 /* 16-bit word PC relative relocation (023). */
318 HOWTO (R_PCRWORD, /* type */
320 1, /* size (0 = byte, 1 = short, 2 = long) */
322 TRUE, /* pc_relative */
324 complain_overflow_signed, /* complain_on_overflow */
325 coff_i386_reloc, /* special_function */
327 TRUE, /* partial_inplace */
328 0x0000ffff, /* src_mask */
329 0x0000ffff, /* dst_mask */
330 PCRELOFFSET), /* pcrel_offset */
331 /* 32-bit longword PC relative relocation (024). */
332 HOWTO (R_PCRLONG, /* type */
334 2, /* size (0 = byte, 1 = short, 2 = long) */
336 TRUE, /* pc_relative */
338 complain_overflow_signed, /* complain_on_overflow */
339 coff_i386_reloc, /* special_function */
341 TRUE, /* partial_inplace */
342 0xffffffff, /* src_mask */
343 0xffffffff, /* dst_mask */
344 PCRELOFFSET) /* pcrel_offset */
347 /* Turn a howto into a reloc nunmber */
349 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
350 #define BADMAG(x) I386BADMAG(x)
351 #define I386 1 /* Customize coffcode.h */
353 #define RTYPE2HOWTO(cache_ptr, dst) \
354 ((cache_ptr)->howto = \
355 ((dst)->r_type < sizeof (howto_table) / sizeof (howto_table[0]) \
356 ? howto_table + (dst)->r_type \
359 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
360 library. On some other COFF targets STYP_BSS is normally
362 #define BSS_NOLOAD_IS_SHARED_LIBRARY
364 /* Compute the addend of a reloc. If the reloc is to a common symbol,
365 the object file contains the value of the common symbol. By the
366 time this is called, the linker may be using a different symbol
367 from a different object file with a different value. Therefore, we
368 hack wildly to locate the original symbol from this file so that we
369 can make the correct adjustment. This macro sets coffsym to the
370 symbol from the original file, and uses it to set the addend value
371 correctly. If this is not a common symbol, the usual addend
372 calculation is done, except that an additional tweak is needed for
374 FIXME: This macro refers to symbols and asect; these are from the
375 calling function, not the macro arguments. */
377 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
379 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
380 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
381 coffsym = (obj_symbols (abfd) \
382 + (cache_ptr->sym_ptr_ptr - symbols)); \
384 coffsym = coff_symbol_from (abfd, ptr); \
385 if (coffsym != (coff_symbol_type *) NULL \
386 && coffsym->native->u.syment.n_scnum == 0) \
387 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
388 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
389 && ptr->section != (asection *) NULL) \
390 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
392 cache_ptr->addend = 0; \
393 if (ptr && howto_table[reloc.r_type].pc_relative) \
394 cache_ptr->addend += asect->vma; \
397 /* We use the special COFF backend linker. For normal i386 COFF, we
398 can use the generic relocate_section routine. For PE, we need our
403 #define coff_relocate_section _bfd_coff_generic_relocate_section
405 #else /* COFF_WITH_PE */
407 /* The PE relocate section routine. The only difference between this
408 and the regular routine is that we don't want to do anything for a
411 static bfd_boolean coff_pe_i386_relocate_section
412 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
413 struct internal_reloc *, struct internal_syment *, asection **));
416 coff_pe_i386_relocate_section (output_bfd, info, input_bfd,
417 input_section, contents, relocs, syms,
420 struct bfd_link_info *info;
422 asection *input_section;
424 struct internal_reloc *relocs;
425 struct internal_syment *syms;
428 if (info->relocatable)
431 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
432 input_section, contents,
433 relocs, syms, sections);
436 #define coff_relocate_section coff_pe_i386_relocate_section
438 #endif /* COFF_WITH_PE */
440 /* Convert an rtype to howto for the COFF backend linker. */
442 static reloc_howto_type *
443 coff_i386_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
444 bfd *abfd ATTRIBUTE_UNUSED;
446 struct internal_reloc *rel;
447 struct coff_link_hash_entry *h;
448 struct internal_syment *sym;
451 reloc_howto_type *howto;
453 if (rel->r_type >= sizeof (howto_table) / sizeof (howto_table[0]))
455 bfd_set_error (bfd_error_bad_value);
459 howto = howto_table + rel->r_type;
462 /* Cancel out code in _bfd_coff_generic_relocate_section. */
466 if (howto->pc_relative)
467 *addendp += sec->vma;
469 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
471 /* This is a common symbol. The section contents include the
472 size (sym->n_value) as an addend. The relocate_section
473 function will be adding in the final value of the symbol. We
474 need to subtract out the current size in order to get the
477 BFD_ASSERT (h != NULL);
480 /* I think we *do* want to bypass this. If we don't, I have
481 seen some data parameters get the wrong relocation address.
482 If I link two versions with and without this section bypassed
483 and then do a binary comparison, the addresses which are
484 different can be looked up in the map. The case in which
485 this section has been bypassed has addresses which correspond
486 to values I can find in the map. */
487 *addendp -= sym->n_value;
492 /* If the output symbol is common (in which case this must be a
493 relocatable link), we need to add in the final size of the
495 if (h != NULL && h->root.type == bfd_link_hash_common)
496 *addendp += h->root.u.c.size;
500 if (howto->pc_relative)
504 /* If the symbol is defined, then the generic code is going to
505 add back the symbol value in order to cancel out an
506 adjustment it made to the addend. However, we set the addend
507 to 0 at the start of this function. We need to adjust here,
508 to avoid the adjustment the generic code will make. FIXME:
509 This is getting a bit hackish. */
510 if (sym != NULL && sym->n_scnum != 0)
511 *addendp -= sym->n_value;
514 if (rel->r_type == R_IMAGEBASE
515 && (bfd_get_flavour(sec->output_section->owner)
516 == bfd_target_coff_flavour))
518 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
521 BFD_ASSERT (sym != NULL);
522 if (rel->r_type == R_SECREL32 && sym != NULL)
526 if (h && (h->type == bfd_link_hash_defined
527 || h->type == bfd_link_hash_defweak))
528 osect_vma = h->root.u.def.section->output_section->vma;
534 /* Sigh, the only way to get the section to offset against
535 is to find it the hard way. */
537 for (sec = abfd->sections, i = 1; i < sym->n_scnum; i++)
540 osect_vma = sec->output_section->vma;
543 *addendp -= osect_vma;
550 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
551 #define coff_bfd_reloc_name_lookup coff_i386_reloc_name_lookup
553 static reloc_howto_type *
554 coff_i386_reloc_type_lookup (abfd, code)
555 bfd *abfd ATTRIBUTE_UNUSED;
556 bfd_reloc_code_real_type code;
561 return howto_table + R_IMAGEBASE;
563 return howto_table + R_DIR32;
564 case BFD_RELOC_32_PCREL:
565 return howto_table + R_PCRLONG;
567 return howto_table + R_RELWORD;
568 case BFD_RELOC_16_PCREL:
569 return howto_table + R_PCRWORD;
571 return howto_table + R_RELBYTE;
572 case BFD_RELOC_8_PCREL:
573 return howto_table + R_PCRBYTE;
575 case BFD_RELOC_32_SECREL:
576 return howto_table + R_SECREL32;
584 static reloc_howto_type *
585 coff_i386_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
590 for (i = 0; i < sizeof (howto_table) / sizeof (howto_table[0]); i++)
591 if (howto_table[i].name != NULL
592 && strcasecmp (howto_table[i].name, r_name) == 0)
593 return &howto_table[i];
598 #define coff_rtype_to_howto coff_i386_rtype_to_howto
600 #ifdef TARGET_UNDERSCORE
602 /* If i386 gcc uses underscores for symbol names, then it does not use
603 a leading dot for local labels, so if TARGET_UNDERSCORE is defined
604 we treat all symbols starting with L as local. */
606 static bfd_boolean coff_i386_is_local_label_name
607 PARAMS ((bfd *, const char *));
610 coff_i386_is_local_label_name (abfd, name)
617 return _bfd_coff_is_local_label_name (abfd, name);
620 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
622 #endif /* TARGET_UNDERSCORE */
624 #include "coffcode.h"
636 "coff-i386", /* name */
638 bfd_target_coff_flavour,
639 BFD_ENDIAN_LITTLE, /* data byte order is little */
640 BFD_ENDIAN_LITTLE, /* header byte order is little */
642 (HAS_RELOC | EXEC_P | /* object flags */
643 HAS_LINENO | HAS_DEBUG |
644 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
646 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
648 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY
650 | SEC_CODE | SEC_DATA),
652 #ifdef TARGET_UNDERSCORE
653 TARGET_UNDERSCORE, /* leading underscore */
655 0, /* leading underscore */
657 '/', /* ar_pad_char */
658 15, /* ar_max_namelen */
660 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
661 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
662 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
663 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
664 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
665 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
667 /* Note that we allow an object file to be treated as a core file as well. */
668 {_bfd_dummy_target, coff_object_p, /* bfd_check_format */
669 bfd_generic_archive_p, coff_object_p},
670 {bfd_false, coff_mkobject, _bfd_generic_mkarchive, /* bfd_set_format */
672 {bfd_false, coff_write_object_contents, /* bfd_write_contents */
673 _bfd_write_archive_contents, bfd_false},
675 BFD_JUMP_TABLE_GENERIC (coff),
676 BFD_JUMP_TABLE_COPY (coff),
677 BFD_JUMP_TABLE_CORE (_bfd_nocore),
678 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
679 BFD_JUMP_TABLE_SYMBOLS (coff),
680 BFD_JUMP_TABLE_RELOCS (coff),
681 BFD_JUMP_TABLE_WRITE (coff),
682 BFD_JUMP_TABLE_LINK (coff),
683 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),