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
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 bfd_reloc_status_type coff_i386_reloc
47 (bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **);
48 static reloc_howto_type *coff_i386_rtype_to_howto
49 (bfd *, asection *, struct internal_reloc *,
50 struct coff_link_hash_entry *, struct internal_syment *,
52 static reloc_howto_type *coff_i386_reloc_type_lookup
53 (bfd *, bfd_reloc_code_real_type);
55 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
56 /* The page size is a guess based on ELF. */
58 #define COFF_PAGE_SIZE 0x1000
60 /* For some reason when using i386 COFF the value stored in the .text
61 section for a reference to a common symbol is the value itself plus
62 any desired offset. Ian Taylor, Cygnus Support. */
64 /* If we are producing relocatable output, we need to do some
65 adjustments to the object file that are not done by the
66 bfd_perform_relocation function. This function is called by every
67 reloc type to make any required adjustments. */
69 static bfd_reloc_status_type
70 coff_i386_reloc (abfd, reloc_entry, symbol, data, input_section, output_bfd,
76 asection *input_section ATTRIBUTE_UNUSED;
78 char **error_message ATTRIBUTE_UNUSED;
83 if (output_bfd == (bfd *) NULL)
84 return bfd_reloc_continue;
87 if (bfd_is_com_section (symbol->section))
90 /* We are relocating a common symbol. The current value in the
91 object file is ORIG + OFFSET, where ORIG is the value of the
92 common symbol as seen by the object file when it was compiled
93 (this may be zero if the symbol was undefined) and OFFSET is
94 the offset into the common symbol (normally zero, but may be
95 non-zero when referring to a field in a common structure).
96 ORIG is the negative of reloc_entry->addend, which is set by
97 the CALC_ADDEND macro below. We want to replace the value in
98 the object file with NEW + OFFSET, where NEW is the value of
99 the common symbol which we are going to put in the final
100 object file. NEW is symbol->value. */
101 diff = symbol->value + reloc_entry->addend;
103 /* In PE mode, we do not offset the common symbol. */
104 diff = reloc_entry->addend;
109 /* For some reason bfd_perform_relocation always effectively
110 ignores the addend for a COFF target when producing
111 relocatable output. This seems to be always wrong for 386
112 COFF, so we handle the addend here instead. */
114 if (output_bfd == (bfd *) NULL)
116 reloc_howto_type *howto = reloc_entry->howto;
118 /* Although PC relative relocations are very similar between
119 PE and non-PE formats, but they are off by 1 << howto->size
120 bytes. For the external relocation, PE is very different
121 from others. See md_apply_fix3 () in gas/config/tc-i386.c.
122 When we link PE and non-PE object files together to
123 generate a non-PE executable, we have to compensate it
125 if (howto->pc_relative && howto->pcrel_offset)
126 diff = -(1 << howto->size);
127 else if (symbol->flags & BSF_WEAK)
128 diff = reloc_entry->addend - symbol->value;
130 diff = -reloc_entry->addend;
134 diff = reloc_entry->addend;
138 /* FIXME: How should this case be handled? */
139 if (reloc_entry->howto->type == R_IMAGEBASE
140 && output_bfd != NULL
141 && bfd_get_flavour(output_bfd) == bfd_target_coff_flavour)
142 diff -= pe_data (output_bfd)->pe_opthdr.ImageBase;
146 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
150 reloc_howto_type *howto = reloc_entry->howto;
151 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
157 char x = bfd_get_8 (abfd, addr);
159 bfd_put_8 (abfd, x, addr);
165 short x = bfd_get_16 (abfd, addr);
167 bfd_put_16 (abfd, (bfd_vma) x, addr);
173 long x = bfd_get_32 (abfd, addr);
175 bfd_put_32 (abfd, (bfd_vma) x, addr);
184 /* Now let bfd_perform_relocation finish everything up. */
185 return bfd_reloc_continue;
189 /* Return TRUE if this relocation should appear in the output .reloc
192 static bfd_boolean in_reloc_p PARAMS ((bfd *, reloc_howto_type *));
194 static bfd_boolean in_reloc_p (abfd, howto)
195 bfd * abfd ATTRIBUTE_UNUSED;
196 reloc_howto_type *howto;
198 return ! howto->pc_relative && howto->type != R_IMAGEBASE
199 && howto->type != R_SECREL32;
201 #endif /* COFF_WITH_PE */
204 #define PCRELOFFSET FALSE
207 static reloc_howto_type howto_table[] =
215 HOWTO (R_DIR32, /* type */
217 2, /* size (0 = byte, 1 = short, 2 = long) */
219 FALSE, /* pc_relative */
221 complain_overflow_bitfield, /* complain_on_overflow */
222 coff_i386_reloc, /* special_function */
224 TRUE, /* partial_inplace */
225 0xffffffff, /* src_mask */
226 0xffffffff, /* dst_mask */
227 TRUE), /* pcrel_offset */
228 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
229 HOWTO (R_IMAGEBASE, /* type */
231 2, /* size (0 = byte, 1 = short, 2 = long) */
233 FALSE, /* pc_relative */
235 complain_overflow_bitfield, /* complain_on_overflow */
236 coff_i386_reloc, /* special_function */
238 TRUE, /* partial_inplace */
239 0xffffffff, /* src_mask */
240 0xffffffff, /* dst_mask */
241 FALSE), /* pcrel_offset */
246 /* 32-bit longword section relative relocation (013). */
247 HOWTO (R_SECREL32, /* type */
249 2, /* size (0 = byte, 1 = short, 2 = long) */
251 FALSE, /* pc_relative */
253 complain_overflow_bitfield, /* complain_on_overflow */
254 coff_i386_reloc, /* special_function */
255 "secrel32", /* name */
256 TRUE, /* partial_inplace */
257 0xffffffff, /* src_mask */
258 0xffffffff, /* dst_mask */
259 TRUE), /* pcrel_offset */
266 /* Byte relocation (017). */
267 HOWTO (R_RELBYTE, /* type */
269 0, /* size (0 = byte, 1 = short, 2 = long) */
271 FALSE, /* pc_relative */
273 complain_overflow_bitfield, /* complain_on_overflow */
274 coff_i386_reloc, /* special_function */
276 TRUE, /* partial_inplace */
277 0x000000ff, /* src_mask */
278 0x000000ff, /* dst_mask */
279 PCRELOFFSET), /* pcrel_offset */
280 /* 16-bit word relocation (020). */
281 HOWTO (R_RELWORD, /* type */
283 1, /* size (0 = byte, 1 = short, 2 = long) */
285 FALSE, /* pc_relative */
287 complain_overflow_bitfield, /* complain_on_overflow */
288 coff_i386_reloc, /* special_function */
290 TRUE, /* partial_inplace */
291 0x0000ffff, /* src_mask */
292 0x0000ffff, /* dst_mask */
293 PCRELOFFSET), /* pcrel_offset */
294 /* 32-bit longword relocation (021). */
295 HOWTO (R_RELLONG, /* type */
297 2, /* size (0 = byte, 1 = short, 2 = long) */
299 FALSE, /* pc_relative */
301 complain_overflow_bitfield, /* complain_on_overflow */
302 coff_i386_reloc, /* special_function */
304 TRUE, /* partial_inplace */
305 0xffffffff, /* src_mask */
306 0xffffffff, /* dst_mask */
307 PCRELOFFSET), /* pcrel_offset */
308 /* Byte PC relative relocation (022). */
309 HOWTO (R_PCRBYTE, /* type */
311 0, /* size (0 = byte, 1 = short, 2 = long) */
313 TRUE, /* pc_relative */
315 complain_overflow_signed, /* complain_on_overflow */
316 coff_i386_reloc, /* special_function */
318 TRUE, /* partial_inplace */
319 0x000000ff, /* src_mask */
320 0x000000ff, /* dst_mask */
321 PCRELOFFSET), /* pcrel_offset */
322 /* 16-bit word PC relative relocation (023). */
323 HOWTO (R_PCRWORD, /* type */
325 1, /* size (0 = byte, 1 = short, 2 = long) */
327 TRUE, /* pc_relative */
329 complain_overflow_signed, /* complain_on_overflow */
330 coff_i386_reloc, /* special_function */
332 TRUE, /* partial_inplace */
333 0x0000ffff, /* src_mask */
334 0x0000ffff, /* dst_mask */
335 PCRELOFFSET), /* pcrel_offset */
336 /* 32-bit longword PC relative relocation (024). */
337 HOWTO (R_PCRLONG, /* type */
339 2, /* size (0 = byte, 1 = short, 2 = long) */
341 TRUE, /* pc_relative */
343 complain_overflow_signed, /* complain_on_overflow */
344 coff_i386_reloc, /* special_function */
346 TRUE, /* partial_inplace */
347 0xffffffff, /* src_mask */
348 0xffffffff, /* dst_mask */
349 PCRELOFFSET) /* pcrel_offset */
352 /* Turn a howto into a reloc nunmber */
354 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
355 #define BADMAG(x) I386BADMAG(x)
356 #define I386 1 /* Customize coffcode.h */
358 #define RTYPE2HOWTO(cache_ptr, dst) \
359 ((cache_ptr)->howto = \
360 ((dst)->r_type < sizeof (howto_table) / sizeof (howto_table[0]) \
361 ? howto_table + (dst)->r_type \
364 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
365 library. On some other COFF targets STYP_BSS is normally
367 #define BSS_NOLOAD_IS_SHARED_LIBRARY
369 /* Compute the addend of a reloc. If the reloc is to a common symbol,
370 the object file contains the value of the common symbol. By the
371 time this is called, the linker may be using a different symbol
372 from a different object file with a different value. Therefore, we
373 hack wildly to locate the original symbol from this file so that we
374 can make the correct adjustment. This macro sets coffsym to the
375 symbol from the original file, and uses it to set the addend value
376 correctly. If this is not a common symbol, the usual addend
377 calculation is done, except that an additional tweak is needed for
379 FIXME: This macro refers to symbols and asect; these are from the
380 calling function, not the macro arguments. */
382 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
384 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
385 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
386 coffsym = (obj_symbols (abfd) \
387 + (cache_ptr->sym_ptr_ptr - symbols)); \
389 coffsym = coff_symbol_from (abfd, ptr); \
390 if (coffsym != (coff_symbol_type *) NULL \
391 && coffsym->native->u.syment.n_scnum == 0) \
392 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
393 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
394 && ptr->section != (asection *) NULL) \
395 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
397 cache_ptr->addend = 0; \
398 if (ptr && howto_table[reloc.r_type].pc_relative) \
399 cache_ptr->addend += asect->vma; \
402 /* We use the special COFF backend linker. For normal i386 COFF, we
403 can use the generic relocate_section routine. For PE, we need our
408 #define coff_relocate_section _bfd_coff_generic_relocate_section
410 #else /* COFF_WITH_PE */
412 /* The PE relocate section routine. The only difference between this
413 and the regular routine is that we don't want to do anything for a
416 static bfd_boolean coff_pe_i386_relocate_section
417 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
418 struct internal_reloc *, struct internal_syment *, asection **));
421 coff_pe_i386_relocate_section (output_bfd, info, input_bfd,
422 input_section, contents, relocs, syms,
425 struct bfd_link_info *info;
427 asection *input_section;
429 struct internal_reloc *relocs;
430 struct internal_syment *syms;
433 if (info->relocatable)
436 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
437 input_section, contents,
438 relocs, syms, sections);
441 #define coff_relocate_section coff_pe_i386_relocate_section
443 #endif /* COFF_WITH_PE */
445 /* Convert an rtype to howto for the COFF backend linker. */
447 static reloc_howto_type *
448 coff_i386_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
449 bfd *abfd ATTRIBUTE_UNUSED;
451 struct internal_reloc *rel;
452 struct coff_link_hash_entry *h;
453 struct internal_syment *sym;
456 reloc_howto_type *howto;
458 if (rel->r_type >= sizeof (howto_table) / sizeof (howto_table[0]))
460 bfd_set_error (bfd_error_bad_value);
464 howto = howto_table + rel->r_type;
467 /* Cancel out code in _bfd_coff_generic_relocate_section. */
471 if (howto->pc_relative)
472 *addendp += sec->vma;
474 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
476 /* This is a common symbol. The section contents include the
477 size (sym->n_value) as an addend. The relocate_section
478 function will be adding in the final value of the symbol. We
479 need to subtract out the current size in order to get the
482 BFD_ASSERT (h != NULL);
485 /* I think we *do* want to bypass this. If we don't, I have
486 seen some data parameters get the wrong relocation address.
487 If I link two versions with and without this section bypassed
488 and then do a binary comparison, the addresses which are
489 different can be looked up in the map. The case in which
490 this section has been bypassed has addresses which correspond
491 to values I can find in the map. */
492 *addendp -= sym->n_value;
497 /* If the output symbol is common (in which case this must be a
498 relocatable link), we need to add in the final size of the
500 if (h != NULL && h->root.type == bfd_link_hash_common)
501 *addendp += h->root.u.c.size;
505 if (howto->pc_relative)
509 /* If the symbol is defined, then the generic code is going to
510 add back the symbol value in order to cancel out an
511 adjustment it made to the addend. However, we set the addend
512 to 0 at the start of this function. We need to adjust here,
513 to avoid the adjustment the generic code will make. FIXME:
514 This is getting a bit hackish. */
515 if (sym != NULL && sym->n_scnum != 0)
516 *addendp -= sym->n_value;
519 if (rel->r_type == R_IMAGEBASE
520 && (bfd_get_flavour(sec->output_section->owner)
521 == bfd_target_coff_flavour))
523 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
526 BFD_ASSERT (sym != NULL);
527 if (rel->r_type == R_SECREL32 && sym != NULL)
531 if (h && (h->type == bfd_link_hash_defined
532 || h->type == bfd_link_hash_defweak))
533 osect_vma = h->root.u.def.section->output_section->vma;
539 /* Sigh, the only way to get the section to offset against
540 is to find it the hard way. */
542 for (s = abfd->sections, i = 1; i < sym->n_scnum; i++)
545 osect_vma = s->output_section->vma;
548 *addendp -= osect_vma;
555 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
556 #define coff_bfd_reloc_name_lookup coff_i386_reloc_name_lookup
558 static reloc_howto_type *
559 coff_i386_reloc_type_lookup (abfd, code)
560 bfd *abfd ATTRIBUTE_UNUSED;
561 bfd_reloc_code_real_type code;
566 return howto_table + R_IMAGEBASE;
568 return howto_table + R_DIR32;
569 case BFD_RELOC_32_PCREL:
570 return howto_table + R_PCRLONG;
572 return howto_table + R_RELWORD;
573 case BFD_RELOC_16_PCREL:
574 return howto_table + R_PCRWORD;
576 return howto_table + R_RELBYTE;
577 case BFD_RELOC_8_PCREL:
578 return howto_table + R_PCRBYTE;
580 case BFD_RELOC_32_SECREL:
581 return howto_table + R_SECREL32;
589 static reloc_howto_type *
590 coff_i386_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
595 for (i = 0; i < sizeof (howto_table) / sizeof (howto_table[0]); i++)
596 if (howto_table[i].name != NULL
597 && strcasecmp (howto_table[i].name, r_name) == 0)
598 return &howto_table[i];
603 #define coff_rtype_to_howto coff_i386_rtype_to_howto
605 #ifdef TARGET_UNDERSCORE
607 /* If i386 gcc uses underscores for symbol names, then it does not use
608 a leading dot for local labels, so if TARGET_UNDERSCORE is defined
609 we treat all symbols starting with L as local. */
611 static bfd_boolean coff_i386_is_local_label_name
612 PARAMS ((bfd *, const char *));
615 coff_i386_is_local_label_name (abfd, name)
622 return _bfd_coff_is_local_label_name (abfd, name);
625 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
627 #endif /* TARGET_UNDERSCORE */
629 #include "coffcode.h"
641 "coff-i386", /* name */
643 bfd_target_coff_flavour,
644 BFD_ENDIAN_LITTLE, /* data byte order is little */
645 BFD_ENDIAN_LITTLE, /* header byte order is little */
647 (HAS_RELOC | EXEC_P | /* object flags */
648 HAS_LINENO | HAS_DEBUG |
649 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
651 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
653 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY
655 | SEC_CODE | SEC_DATA),
657 #ifdef TARGET_UNDERSCORE
658 TARGET_UNDERSCORE, /* leading underscore */
660 0, /* leading underscore */
662 '/', /* ar_pad_char */
663 15, /* ar_max_namelen */
664 0, /* match priority. */
666 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
667 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
668 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
669 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
670 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
671 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
673 /* Note that we allow an object file to be treated as a core file as well. */
674 {_bfd_dummy_target, coff_object_p, /* bfd_check_format */
675 bfd_generic_archive_p, coff_object_p},
676 {bfd_false, coff_mkobject, _bfd_generic_mkarchive, /* bfd_set_format */
678 {bfd_false, coff_write_object_contents, /* bfd_write_contents */
679 _bfd_write_archive_contents, bfd_false},
681 BFD_JUMP_TABLE_GENERIC (coff),
682 BFD_JUMP_TABLE_COPY (coff),
683 BFD_JUMP_TABLE_CORE (_bfd_nocore),
684 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
685 BFD_JUMP_TABLE_SYMBOLS (coff),
686 BFD_JUMP_TABLE_RELOCS (coff),
687 BFD_JUMP_TABLE_WRITE (coff),
688 BFD_JUMP_TABLE_LINK (coff),
689 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),