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
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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
27 #include "coff/i386.h"
29 #include "coff/internal.h"
36 #include "coff/go32exe.h"
41 static bfd_reloc_status_type coff_i386_reloc
42 PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
43 static reloc_howto_type *coff_i386_rtype_to_howto
44 PARAMS ((bfd *, asection *, struct internal_reloc *,
45 struct coff_link_hash_entry *, struct internal_syment *,
47 static reloc_howto_type *coff_i386_reloc_type_lookup
48 PARAMS ((bfd *, bfd_reloc_code_real_type));
50 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
51 /* The page size is a guess based on ELF. */
53 #define COFF_PAGE_SIZE 0x1000
55 /* For some reason when using i386 COFF the value stored in the .text
56 section for a reference to a common symbol is the value itself plus
57 any desired offset. Ian Taylor, Cygnus Support. */
59 /* If we are producing relocatable output, we need to do some
60 adjustments to the object file that are not done by the
61 bfd_perform_relocation function. This function is called by every
62 reloc type to make any required adjustments. */
64 static bfd_reloc_status_type
65 coff_i386_reloc (abfd, reloc_entry, symbol, data, input_section, output_bfd,
71 asection *input_section ATTRIBUTE_UNUSED;
73 char **error_message ATTRIBUTE_UNUSED;
78 if (output_bfd == (bfd *) NULL)
79 return bfd_reloc_continue;
82 if (bfd_is_com_section (symbol->section))
85 /* We are relocating a common symbol. The current value in the
86 object file is ORIG + OFFSET, where ORIG is the value of the
87 common symbol as seen by the object file when it was compiled
88 (this may be zero if the symbol was undefined) and OFFSET is
89 the offset into the common symbol (normally zero, but may be
90 non-zero when referring to a field in a common structure).
91 ORIG is the negative of reloc_entry->addend, which is set by
92 the CALC_ADDEND macro below. We want to replace the value in
93 the object file with NEW + OFFSET, where NEW is the value of
94 the common symbol which we are going to put in the final
95 object file. NEW is symbol->value. */
96 diff = symbol->value + reloc_entry->addend;
98 /* In PE mode, we do not offset the common symbol. */
99 diff = reloc_entry->addend;
104 /* For some reason bfd_perform_relocation always effectively
105 ignores the addend for a COFF target when producing
106 relocatable output. This seems to be always wrong for 386
107 COFF, so we handle the addend here instead. */
109 if (output_bfd == (bfd *) NULL)
111 reloc_howto_type *howto = reloc_entry->howto;
113 /* Although PC relative relocations are very similar between
114 PE and non-PE formats, but they are off by 1 << howto->size
115 bytes. For the external relocation, PE is very different
116 from others. See md_apply_fix3 () in gas/config/tc-i386.c.
117 When we link PE and non-PE object files together to
118 generate a non-PE executable, we have to compensate it
120 if (howto->pc_relative && howto->pcrel_offset)
121 diff = -(1 << howto->size);
122 else if (symbol->flags & BSF_WEAK)
123 diff = reloc_entry->addend - symbol->value;
125 diff = -reloc_entry->addend;
129 diff = reloc_entry->addend;
133 /* FIXME: How should this case be handled? */
134 if (reloc_entry->howto->type == R_IMAGEBASE
135 && output_bfd != NULL
136 && bfd_get_flavour(output_bfd) == bfd_target_coff_flavour)
137 diff -= pe_data (output_bfd)->pe_opthdr.ImageBase;
141 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
145 reloc_howto_type *howto = reloc_entry->howto;
146 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
152 char x = bfd_get_8 (abfd, addr);
154 bfd_put_8 (abfd, x, addr);
160 short x = bfd_get_16 (abfd, addr);
162 bfd_put_16 (abfd, (bfd_vma) x, addr);
168 long x = bfd_get_32 (abfd, addr);
170 bfd_put_32 (abfd, (bfd_vma) x, addr);
179 /* Now let bfd_perform_relocation finish everything up. */
180 return bfd_reloc_continue;
184 /* Return TRUE if this relocation should appear in the output .reloc
187 static bfd_boolean in_reloc_p PARAMS ((bfd *, reloc_howto_type *));
189 static bfd_boolean in_reloc_p (abfd, howto)
190 bfd * abfd ATTRIBUTE_UNUSED;
191 reloc_howto_type *howto;
193 return ! howto->pc_relative && howto->type != R_IMAGEBASE;
195 #endif /* COFF_WITH_PE */
198 #define PCRELOFFSET FALSE
201 static reloc_howto_type howto_table[] =
209 HOWTO (R_DIR32, /* type */
211 2, /* size (0 = byte, 1 = short, 2 = long) */
213 FALSE, /* pc_relative */
215 complain_overflow_bitfield, /* complain_on_overflow */
216 coff_i386_reloc, /* special_function */
218 TRUE, /* partial_inplace */
219 0xffffffff, /* src_mask */
220 0xffffffff, /* dst_mask */
221 TRUE), /* pcrel_offset */
222 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
223 HOWTO (R_IMAGEBASE, /* type */
225 2, /* size (0 = byte, 1 = short, 2 = long) */
227 FALSE, /* pc_relative */
229 complain_overflow_bitfield, /* complain_on_overflow */
230 coff_i386_reloc, /* special_function */
232 TRUE, /* partial_inplace */
233 0xffffffff, /* src_mask */
234 0xffffffff, /* dst_mask */
235 FALSE), /* pcrel_offset */
240 /* 32-bit longword section relative relocation (013). */
241 HOWTO (R_SECREL32, /* type */
243 2, /* size (0 = byte, 1 = short, 2 = long) */
245 FALSE, /* pc_relative */
247 complain_overflow_bitfield, /* complain_on_overflow */
248 coff_i386_reloc, /* special_function */
249 "secrel32", /* name */
250 TRUE, /* partial_inplace */
251 0xffffffff, /* src_mask */
252 0xffffffff, /* dst_mask */
253 TRUE), /* pcrel_offset */
260 /* Byte relocation (017). */
261 HOWTO (R_RELBYTE, /* type */
263 0, /* size (0 = byte, 1 = short, 2 = long) */
265 FALSE, /* pc_relative */
267 complain_overflow_bitfield, /* complain_on_overflow */
268 coff_i386_reloc, /* special_function */
270 TRUE, /* partial_inplace */
271 0x000000ff, /* src_mask */
272 0x000000ff, /* dst_mask */
273 PCRELOFFSET), /* pcrel_offset */
274 /* 16-bit word relocation (020). */
275 HOWTO (R_RELWORD, /* type */
277 1, /* size (0 = byte, 1 = short, 2 = long) */
279 FALSE, /* pc_relative */
281 complain_overflow_bitfield, /* complain_on_overflow */
282 coff_i386_reloc, /* special_function */
284 TRUE, /* partial_inplace */
285 0x0000ffff, /* src_mask */
286 0x0000ffff, /* dst_mask */
287 PCRELOFFSET), /* pcrel_offset */
288 /* 32-bit longword relocation (021). */
289 HOWTO (R_RELLONG, /* type */
291 2, /* size (0 = byte, 1 = short, 2 = long) */
293 FALSE, /* pc_relative */
295 complain_overflow_bitfield, /* complain_on_overflow */
296 coff_i386_reloc, /* special_function */
298 TRUE, /* partial_inplace */
299 0xffffffff, /* src_mask */
300 0xffffffff, /* dst_mask */
301 PCRELOFFSET), /* pcrel_offset */
302 /* Byte PC relative relocation (022). */
303 HOWTO (R_PCRBYTE, /* type */
305 0, /* size (0 = byte, 1 = short, 2 = long) */
307 TRUE, /* pc_relative */
309 complain_overflow_signed, /* complain_on_overflow */
310 coff_i386_reloc, /* special_function */
312 TRUE, /* partial_inplace */
313 0x000000ff, /* src_mask */
314 0x000000ff, /* dst_mask */
315 PCRELOFFSET), /* pcrel_offset */
316 /* 16-bit word PC relative relocation (023). */
317 HOWTO (R_PCRWORD, /* type */
319 1, /* size (0 = byte, 1 = short, 2 = long) */
321 TRUE, /* pc_relative */
323 complain_overflow_signed, /* complain_on_overflow */
324 coff_i386_reloc, /* special_function */
326 TRUE, /* partial_inplace */
327 0x0000ffff, /* src_mask */
328 0x0000ffff, /* dst_mask */
329 PCRELOFFSET), /* pcrel_offset */
330 /* 32-bit longword PC relative relocation (024). */
331 HOWTO (R_PCRLONG, /* type */
333 2, /* size (0 = byte, 1 = short, 2 = long) */
335 TRUE, /* pc_relative */
337 complain_overflow_signed, /* complain_on_overflow */
338 coff_i386_reloc, /* special_function */
340 TRUE, /* partial_inplace */
341 0xffffffff, /* src_mask */
342 0xffffffff, /* dst_mask */
343 PCRELOFFSET) /* pcrel_offset */
346 /* Turn a howto into a reloc nunmber */
348 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
349 #define BADMAG(x) I386BADMAG(x)
350 #define I386 1 /* Customize coffcode.h */
352 #define RTYPE2HOWTO(cache_ptr, dst) \
353 ((cache_ptr)->howto = \
354 ((dst)->r_type < sizeof (howto_table) / sizeof (howto_table[0]) \
355 ? howto_table + (dst)->r_type \
358 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
359 library. On some other COFF targets STYP_BSS is normally
361 #define BSS_NOLOAD_IS_SHARED_LIBRARY
363 /* Compute the addend of a reloc. If the reloc is to a common symbol,
364 the object file contains the value of the common symbol. By the
365 time this is called, the linker may be using a different symbol
366 from a different object file with a different value. Therefore, we
367 hack wildly to locate the original symbol from this file so that we
368 can make the correct adjustment. This macro sets coffsym to the
369 symbol from the original file, and uses it to set the addend value
370 correctly. If this is not a common symbol, the usual addend
371 calculation is done, except that an additional tweak is needed for
373 FIXME: This macro refers to symbols and asect; these are from the
374 calling function, not the macro arguments. */
376 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
378 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
379 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
380 coffsym = (obj_symbols (abfd) \
381 + (cache_ptr->sym_ptr_ptr - symbols)); \
383 coffsym = coff_symbol_from (abfd, ptr); \
384 if (coffsym != (coff_symbol_type *) NULL \
385 && coffsym->native->u.syment.n_scnum == 0) \
386 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
387 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
388 && ptr->section != (asection *) NULL) \
389 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
391 cache_ptr->addend = 0; \
392 if (ptr && howto_table[reloc.r_type].pc_relative) \
393 cache_ptr->addend += asect->vma; \
396 /* We use the special COFF backend linker. For normal i386 COFF, we
397 can use the generic relocate_section routine. For PE, we need our
402 #define coff_relocate_section _bfd_coff_generic_relocate_section
404 #else /* COFF_WITH_PE */
406 /* The PE relocate section routine. The only difference between this
407 and the regular routine is that we don't want to do anything for a
410 static bfd_boolean coff_pe_i386_relocate_section
411 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
412 struct internal_reloc *, struct internal_syment *, asection **));
415 coff_pe_i386_relocate_section (output_bfd, info, input_bfd,
416 input_section, contents, relocs, syms,
419 struct bfd_link_info *info;
421 asection *input_section;
423 struct internal_reloc *relocs;
424 struct internal_syment *syms;
427 if (info->relocatable)
430 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
431 input_section, contents,
432 relocs, syms, sections);
435 #define coff_relocate_section coff_pe_i386_relocate_section
437 #endif /* COFF_WITH_PE */
439 /* Convert an rtype to howto for the COFF backend linker. */
441 static reloc_howto_type *
442 coff_i386_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
443 bfd *abfd ATTRIBUTE_UNUSED;
445 struct internal_reloc *rel;
446 struct coff_link_hash_entry *h;
447 struct internal_syment *sym;
450 reloc_howto_type *howto;
452 if (rel->r_type > sizeof (howto_table) / sizeof (howto_table[0]))
454 bfd_set_error (bfd_error_bad_value);
458 howto = howto_table + rel->r_type;
461 /* Cancel out code in _bfd_coff_generic_relocate_section. */
465 if (howto->pc_relative)
466 *addendp += sec->vma;
468 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
470 /* This is a common symbol. The section contents include the
471 size (sym->n_value) as an addend. The relocate_section
472 function will be adding in the final value of the symbol. We
473 need to subtract out the current size in order to get the
476 BFD_ASSERT (h != NULL);
479 /* I think we *do* want to bypass this. If we don't, I have
480 seen some data parameters get the wrong relocation address.
481 If I link two versions with and without this section bypassed
482 and then do a binary comparison, the addresses which are
483 different can be looked up in the map. The case in which
484 this section has been bypassed has addresses which correspond
485 to values I can find in the map. */
486 *addendp -= sym->n_value;
491 /* If the output symbol is common (in which case this must be a
492 relocatable link), we need to add in the final size of the
494 if (h != NULL && h->root.type == bfd_link_hash_common)
495 *addendp += h->root.u.c.size;
499 if (howto->pc_relative)
503 /* If the symbol is defined, then the generic code is going to
504 add back the symbol value in order to cancel out an
505 adjustment it made to the addend. However, we set the addend
506 to 0 at the start of this function. We need to adjust here,
507 to avoid the adjustment the generic code will make. FIXME:
508 This is getting a bit hackish. */
509 if (sym != NULL && sym->n_scnum != 0)
510 *addendp -= sym->n_value;
513 if (rel->r_type == R_IMAGEBASE
514 && (bfd_get_flavour(sec->output_section->owner)
515 == bfd_target_coff_flavour))
517 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
520 if (rel->r_type == R_SECREL32)
524 if (h && (h->type == bfd_link_hash_defined
525 || h->type == bfd_link_hash_defweak))
526 osect_vma = h->root.u.def.section->output_section->vma;
532 /* Sigh, the only way to get the section to offset against
533 is to find it the hard way. */
535 for (sec = abfd->sections, i = 1; i < sym->n_scnum; i++)
538 osect_vma = sec->output_section->vma;
541 *addendp -= osect_vma;
548 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
550 static reloc_howto_type *
551 coff_i386_reloc_type_lookup (abfd, code)
552 bfd *abfd ATTRIBUTE_UNUSED;
553 bfd_reloc_code_real_type code;
558 return howto_table + R_IMAGEBASE;
560 return howto_table + R_DIR32;
561 case BFD_RELOC_32_PCREL:
562 return howto_table + R_PCRLONG;
564 return howto_table + R_RELWORD;
565 case BFD_RELOC_16_PCREL:
566 return howto_table + R_PCRWORD;
568 return howto_table + R_RELBYTE;
569 case BFD_RELOC_8_PCREL:
570 return howto_table + R_PCRBYTE;
572 case BFD_RELOC_32_SECREL:
573 return howto_table + R_SECREL32;
581 #define coff_rtype_to_howto coff_i386_rtype_to_howto
583 #ifdef TARGET_UNDERSCORE
585 /* If i386 gcc uses underscores for symbol names, then it does not use
586 a leading dot for local labels, so if TARGET_UNDERSCORE is defined
587 we treat all symbols starting with L as local. */
589 static bfd_boolean coff_i386_is_local_label_name
590 PARAMS ((bfd *, const char *));
593 coff_i386_is_local_label_name (abfd, name)
600 return _bfd_coff_is_local_label_name (abfd, name);
603 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
605 #endif /* TARGET_UNDERSCORE */
607 #include "coffcode.h"
619 "coff-i386", /* name */
621 bfd_target_coff_flavour,
622 BFD_ENDIAN_LITTLE, /* data byte order is little */
623 BFD_ENDIAN_LITTLE, /* header byte order is little */
625 (HAS_RELOC | EXEC_P | /* object flags */
626 HAS_LINENO | HAS_DEBUG |
627 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
629 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
631 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY
633 | SEC_CODE | SEC_DATA),
635 #ifdef TARGET_UNDERSCORE
636 TARGET_UNDERSCORE, /* leading underscore */
638 0, /* leading underscore */
640 '/', /* ar_pad_char */
641 15, /* ar_max_namelen */
643 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
644 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
645 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
646 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
647 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
648 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
650 /* Note that we allow an object file to be treated as a core file as well. */
651 {_bfd_dummy_target, coff_object_p, /* bfd_check_format */
652 bfd_generic_archive_p, coff_object_p},
653 {bfd_false, coff_mkobject, _bfd_generic_mkarchive, /* bfd_set_format */
655 {bfd_false, coff_write_object_contents, /* bfd_write_contents */
656 _bfd_write_archive_contents, bfd_false},
658 BFD_JUMP_TABLE_GENERIC (coff),
659 BFD_JUMP_TABLE_COPY (coff),
660 BFD_JUMP_TABLE_CORE (_bfd_nocore),
661 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
662 BFD_JUMP_TABLE_SYMBOLS (coff),
663 BFD_JUMP_TABLE_RELOCS (coff),
664 BFD_JUMP_TABLE_WRITE (coff),
665 BFD_JUMP_TABLE_LINK (coff),
666 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),