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, 2005, 2007, 2008, 2009, 2010, 2011, 2012
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"
40 #ifndef bfd_pe_print_pdata
41 #define bfd_pe_print_pdata NULL
46 static reloc_howto_type *coff_i386_rtype_to_howto
47 (bfd *, asection *, struct internal_reloc *,
48 struct coff_link_hash_entry *, struct internal_syment *,
50 static reloc_howto_type *coff_i386_reloc_type_lookup
51 (bfd *, bfd_reloc_code_real_type);
53 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
54 /* The page size is a guess based on ELF. */
56 #define COFF_PAGE_SIZE 0x1000
58 /* For some reason when using i386 COFF the value stored in the .text
59 section for a reference to a common symbol is the value itself plus
60 any desired offset. Ian Taylor, Cygnus Support. */
62 /* If we are producing relocatable output, we need to do some
63 adjustments to the object file that are not done by the
64 bfd_perform_relocation function. This function is called by every
65 reloc type to make any required adjustments. */
67 static bfd_reloc_status_type
68 coff_i386_reloc (bfd *abfd,
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 (bfd * abfd ATTRIBUTE_UNUSED,
189 reloc_howto_type *howto)
191 return ! howto->pc_relative && howto->type != R_IMAGEBASE
192 && howto->type != R_SECREL32;
194 #endif /* COFF_WITH_PE */
197 #define PCRELOFFSET FALSE
200 static reloc_howto_type howto_table[] =
208 HOWTO (R_DIR32, /* type */
210 2, /* size (0 = byte, 1 = short, 2 = long) */
212 FALSE, /* pc_relative */
214 complain_overflow_bitfield, /* complain_on_overflow */
215 coff_i386_reloc, /* special_function */
217 TRUE, /* partial_inplace */
218 0xffffffff, /* src_mask */
219 0xffffffff, /* dst_mask */
220 TRUE), /* pcrel_offset */
221 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
222 HOWTO (R_IMAGEBASE, /* type */
224 2, /* size (0 = byte, 1 = short, 2 = long) */
226 FALSE, /* pc_relative */
228 complain_overflow_bitfield, /* complain_on_overflow */
229 coff_i386_reloc, /* special_function */
231 TRUE, /* partial_inplace */
232 0xffffffff, /* src_mask */
233 0xffffffff, /* dst_mask */
234 FALSE), /* pcrel_offset */
239 /* 32-bit longword section relative relocation (013). */
240 HOWTO (R_SECREL32, /* type */
242 2, /* size (0 = byte, 1 = short, 2 = long) */
244 FALSE, /* pc_relative */
246 complain_overflow_bitfield, /* complain_on_overflow */
247 coff_i386_reloc, /* special_function */
248 "secrel32", /* name */
249 TRUE, /* partial_inplace */
250 0xffffffff, /* src_mask */
251 0xffffffff, /* dst_mask */
252 TRUE), /* pcrel_offset */
259 /* Byte relocation (017). */
260 HOWTO (R_RELBYTE, /* type */
262 0, /* size (0 = byte, 1 = short, 2 = long) */
264 FALSE, /* pc_relative */
266 complain_overflow_bitfield, /* complain_on_overflow */
267 coff_i386_reloc, /* special_function */
269 TRUE, /* partial_inplace */
270 0x000000ff, /* src_mask */
271 0x000000ff, /* dst_mask */
272 PCRELOFFSET), /* pcrel_offset */
273 /* 16-bit word relocation (020). */
274 HOWTO (R_RELWORD, /* type */
276 1, /* size (0 = byte, 1 = short, 2 = long) */
278 FALSE, /* pc_relative */
280 complain_overflow_bitfield, /* complain_on_overflow */
281 coff_i386_reloc, /* special_function */
283 TRUE, /* partial_inplace */
284 0x0000ffff, /* src_mask */
285 0x0000ffff, /* dst_mask */
286 PCRELOFFSET), /* pcrel_offset */
287 /* 32-bit longword relocation (021). */
288 HOWTO (R_RELLONG, /* type */
290 2, /* size (0 = byte, 1 = short, 2 = long) */
292 FALSE, /* pc_relative */
294 complain_overflow_bitfield, /* complain_on_overflow */
295 coff_i386_reloc, /* special_function */
297 TRUE, /* partial_inplace */
298 0xffffffff, /* src_mask */
299 0xffffffff, /* dst_mask */
300 PCRELOFFSET), /* pcrel_offset */
301 /* Byte PC relative relocation (022). */
302 HOWTO (R_PCRBYTE, /* type */
304 0, /* size (0 = byte, 1 = short, 2 = long) */
306 TRUE, /* pc_relative */
308 complain_overflow_signed, /* complain_on_overflow */
309 coff_i386_reloc, /* special_function */
311 TRUE, /* partial_inplace */
312 0x000000ff, /* src_mask */
313 0x000000ff, /* dst_mask */
314 PCRELOFFSET), /* pcrel_offset */
315 /* 16-bit word PC relative relocation (023). */
316 HOWTO (R_PCRWORD, /* type */
318 1, /* size (0 = byte, 1 = short, 2 = long) */
320 TRUE, /* pc_relative */
322 complain_overflow_signed, /* complain_on_overflow */
323 coff_i386_reloc, /* special_function */
325 TRUE, /* partial_inplace */
326 0x0000ffff, /* src_mask */
327 0x0000ffff, /* dst_mask */
328 PCRELOFFSET), /* pcrel_offset */
329 /* 32-bit longword PC relative relocation (024). */
330 HOWTO (R_PCRLONG, /* type */
332 2, /* size (0 = byte, 1 = short, 2 = long) */
334 TRUE, /* pc_relative */
336 complain_overflow_signed, /* complain_on_overflow */
337 coff_i386_reloc, /* special_function */
339 TRUE, /* partial_inplace */
340 0xffffffff, /* src_mask */
341 0xffffffff, /* dst_mask */
342 PCRELOFFSET) /* pcrel_offset */
345 /* Turn a howto into a reloc nunmber */
347 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
348 #define BADMAG(x) I386BADMAG(x)
349 #define I386 1 /* Customize coffcode.h */
351 #define RTYPE2HOWTO(cache_ptr, dst) \
352 ((cache_ptr)->howto = \
353 ((dst)->r_type < sizeof (howto_table) / sizeof (howto_table[0]) \
354 ? howto_table + (dst)->r_type \
357 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
358 library. On some other COFF targets STYP_BSS is normally
360 #define BSS_NOLOAD_IS_SHARED_LIBRARY
362 /* Compute the addend of a reloc. If the reloc is to a common symbol,
363 the object file contains the value of the common symbol. By the
364 time this is called, the linker may be using a different symbol
365 from a different object file with a different value. Therefore, we
366 hack wildly to locate the original symbol from this file so that we
367 can make the correct adjustment. This macro sets coffsym to the
368 symbol from the original file, and uses it to set the addend value
369 correctly. If this is not a common symbol, the usual addend
370 calculation is done, except that an additional tweak is needed for
372 FIXME: This macro refers to symbols and asect; these are from the
373 calling function, not the macro arguments. */
375 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
377 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
378 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
379 coffsym = (obj_symbols (abfd) \
380 + (cache_ptr->sym_ptr_ptr - symbols)); \
382 coffsym = coff_symbol_from (abfd, ptr); \
383 if (coffsym != (coff_symbol_type *) NULL \
384 && coffsym->native->u.syment.n_scnum == 0) \
385 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
386 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
387 && ptr->section != (asection *) NULL) \
388 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
390 cache_ptr->addend = 0; \
391 if (ptr && howto_table[reloc.r_type].pc_relative) \
392 cache_ptr->addend += asect->vma; \
395 /* We use the special COFF backend linker. For normal i386 COFF, we
396 can use the generic relocate_section routine. For PE, we need our
401 #define coff_relocate_section _bfd_coff_generic_relocate_section
403 #else /* COFF_WITH_PE */
405 /* The PE relocate section routine. The only difference between this
406 and the regular routine is that we don't want to do anything for a
410 coff_pe_i386_relocate_section (bfd *output_bfd,
411 struct bfd_link_info *info,
413 asection *input_section,
415 struct internal_reloc *relocs,
416 struct internal_syment *syms,
419 if (info->relocatable)
422 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
423 input_section, contents,
424 relocs, syms, sections);
427 #define coff_relocate_section coff_pe_i386_relocate_section
429 #endif /* COFF_WITH_PE */
431 /* Convert an rtype to howto for the COFF backend linker. */
433 static reloc_howto_type *
434 coff_i386_rtype_to_howto (bfd *abfd ATTRIBUTE_UNUSED,
436 struct internal_reloc *rel,
437 struct coff_link_hash_entry *h,
438 struct internal_syment *sym,
441 reloc_howto_type *howto;
443 if (rel->r_type >= sizeof (howto_table) / sizeof (howto_table[0]))
445 bfd_set_error (bfd_error_bad_value);
449 howto = howto_table + rel->r_type;
452 /* Cancel out code in _bfd_coff_generic_relocate_section. */
456 if (howto->pc_relative)
457 *addendp += sec->vma;
459 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
461 /* This is a common symbol. The section contents include the
462 size (sym->n_value) as an addend. The relocate_section
463 function will be adding in the final value of the symbol. We
464 need to subtract out the current size in order to get the
467 BFD_ASSERT (h != NULL);
470 /* I think we *do* want to bypass this. If we don't, I have
471 seen some data parameters get the wrong relocation address.
472 If I link two versions with and without this section bypassed
473 and then do a binary comparison, the addresses which are
474 different can be looked up in the map. The case in which
475 this section has been bypassed has addresses which correspond
476 to values I can find in the map. */
477 *addendp -= sym->n_value;
482 /* If the output symbol is common (in which case this must be a
483 relocatable link), we need to add in the final size of the
485 if (h != NULL && h->root.type == bfd_link_hash_common)
486 *addendp += h->root.u.c.size;
490 if (howto->pc_relative)
494 /* If the symbol is defined, then the generic code is going to
495 add back the symbol value in order to cancel out an
496 adjustment it made to the addend. However, we set the addend
497 to 0 at the start of this function. We need to adjust here,
498 to avoid the adjustment the generic code will make. FIXME:
499 This is getting a bit hackish. */
500 if (sym != NULL && sym->n_scnum != 0)
501 *addendp -= sym->n_value;
504 if (rel->r_type == R_IMAGEBASE
505 && (bfd_get_flavour(sec->output_section->owner)
506 == bfd_target_coff_flavour))
508 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
511 BFD_ASSERT (sym != NULL);
512 if (rel->r_type == R_SECREL32 && sym != NULL)
516 if (h && (h->root.type == bfd_link_hash_defined
517 || h->root.type == bfd_link_hash_defweak))
518 osect_vma = h->root.u.def.section->output_section->vma;
524 /* Sigh, the only way to get the section to offset against
525 is to find it the hard way. */
527 for (s = abfd->sections, i = 1; i < sym->n_scnum; i++)
530 osect_vma = s->output_section->vma;
533 *addendp -= osect_vma;
540 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
541 #define coff_bfd_reloc_name_lookup coff_i386_reloc_name_lookup
543 static reloc_howto_type *
544 coff_i386_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
545 bfd_reloc_code_real_type code)
550 return howto_table + R_IMAGEBASE;
552 return howto_table + R_DIR32;
553 case BFD_RELOC_32_PCREL:
554 return howto_table + R_PCRLONG;
556 return howto_table + R_RELWORD;
557 case BFD_RELOC_16_PCREL:
558 return howto_table + R_PCRWORD;
560 return howto_table + R_RELBYTE;
561 case BFD_RELOC_8_PCREL:
562 return howto_table + R_PCRBYTE;
564 case BFD_RELOC_32_SECREL:
565 return howto_table + R_SECREL32;
573 static reloc_howto_type *
574 coff_i386_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
579 for (i = 0; i < sizeof (howto_table) / sizeof (howto_table[0]); i++)
580 if (howto_table[i].name != NULL
581 && strcasecmp (howto_table[i].name, r_name) == 0)
582 return &howto_table[i];
587 #define coff_rtype_to_howto coff_i386_rtype_to_howto
589 #ifdef TARGET_UNDERSCORE
591 /* If i386 gcc uses underscores for symbol names, then it does not use
592 a leading dot for local labels, so if TARGET_UNDERSCORE is defined
593 we treat all symbols starting with L as local. */
596 coff_i386_is_local_label_name (bfd *abfd, const char *name)
601 return _bfd_coff_is_local_label_name (abfd, name);
604 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
606 #endif /* TARGET_UNDERSCORE */
608 #include "coffcode.h"
610 #define _bfd_generic_find_nearest_line_discriminator \
611 coff_find_nearest_line_discriminator
623 "coff-i386", /* name */
625 bfd_target_coff_flavour,
626 BFD_ENDIAN_LITTLE, /* data byte order is little */
627 BFD_ENDIAN_LITTLE, /* header byte order is little */
629 (HAS_RELOC | EXEC_P | /* object flags */
630 HAS_LINENO | HAS_DEBUG |
631 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED | BFD_COMPRESS | BFD_DECOMPRESS ),
633 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
635 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY | SEC_DEBUGGING
637 | SEC_CODE | SEC_DATA | SEC_EXCLUDE ),
639 #ifdef TARGET_UNDERSCORE
640 TARGET_UNDERSCORE, /* leading underscore */
642 0, /* leading underscore */
644 '/', /* ar_pad_char */
645 15, /* ar_max_namelen */
646 0, /* match priority. */
648 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
649 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
650 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
651 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
652 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
653 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
655 /* Note that we allow an object file to be treated as a core file as well. */
656 /* bfd_check_format */
657 #ifdef COFF_CHECK_FORMAT
658 {_bfd_dummy_target, COFF_CHECK_FORMAT,
659 bfd_generic_archive_p, COFF_CHECK_FORMAT},
661 {_bfd_dummy_target, coff_object_p, bfd_generic_archive_p, coff_object_p},
663 {bfd_false, coff_mkobject, _bfd_generic_mkarchive, /* bfd_set_format */
665 {bfd_false, coff_write_object_contents, /* bfd_write_contents */
666 _bfd_write_archive_contents, bfd_false},
668 BFD_JUMP_TABLE_GENERIC (coff),
669 BFD_JUMP_TABLE_COPY (coff),
670 BFD_JUMP_TABLE_CORE (_bfd_nocore),
671 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
672 BFD_JUMP_TABLE_SYMBOLS (coff),
673 BFD_JUMP_TABLE_RELOCS (coff),
674 BFD_JUMP_TABLE_WRITE (coff),
675 BFD_JUMP_TABLE_LINK (coff),
676 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),