1 /* BFD back-end for Intel 386 COFF files.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
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 relocateable 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 relocateable 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 == true && howto->pcrel_offset == true)
121 diff = -(1 << howto->size);
123 diff = -reloc_entry->addend;
127 diff = reloc_entry->addend;
131 /* FIXME: How should this case be handled? */
132 if (reloc_entry->howto->type == R_IMAGEBASE
133 && output_bfd != NULL
134 && bfd_get_flavour(output_bfd) == bfd_target_coff_flavour)
135 diff -= pe_data (output_bfd)->pe_opthdr.ImageBase;
139 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
143 reloc_howto_type *howto = reloc_entry->howto;
144 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
150 char x = bfd_get_8 (abfd, addr);
152 bfd_put_8 (abfd, x, addr);
158 short x = bfd_get_16 (abfd, addr);
160 bfd_put_16 (abfd, x, addr);
166 long x = bfd_get_32 (abfd, addr);
168 bfd_put_32 (abfd, x, addr);
177 /* Now let bfd_perform_relocation finish everything up. */
178 return bfd_reloc_continue;
182 /* Return true if this relocation should appear in the output .reloc
185 static boolean in_reloc_p PARAMS ((bfd *, reloc_howto_type *));
187 static boolean in_reloc_p (abfd, howto)
188 bfd * abfd ATTRIBUTE_UNUSED;
189 reloc_howto_type *howto;
191 return ! howto->pc_relative && howto->type != R_IMAGEBASE;
193 #endif /* COFF_WITH_PE */
196 #define PCRELOFFSET false
199 static reloc_howto_type howto_table[] =
207 HOWTO (R_DIR32, /* type */
209 2, /* size (0 = byte, 1 = short, 2 = long) */
211 false, /* pc_relative */
213 complain_overflow_bitfield, /* complain_on_overflow */
214 coff_i386_reloc, /* special_function */
216 true, /* partial_inplace */
217 0xffffffff, /* src_mask */
218 0xffffffff, /* dst_mask */
219 true), /* pcrel_offset */
220 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
221 HOWTO (R_IMAGEBASE, /* type */
223 2, /* size (0 = byte, 1 = short, 2 = long) */
225 false, /* pc_relative */
227 complain_overflow_bitfield, /* complain_on_overflow */
228 coff_i386_reloc, /* special_function */
230 true, /* partial_inplace */
231 0xffffffff, /* src_mask */
232 0xffffffff, /* dst_mask */
233 false), /* pcrel_offset */
241 /* Byte relocation (017). */
242 HOWTO (R_RELBYTE, /* type */
244 0, /* size (0 = byte, 1 = short, 2 = long) */
246 false, /* pc_relative */
248 complain_overflow_bitfield, /* complain_on_overflow */
249 coff_i386_reloc, /* special_function */
251 true, /* partial_inplace */
252 0x000000ff, /* src_mask */
253 0x000000ff, /* dst_mask */
254 PCRELOFFSET), /* pcrel_offset */
255 /* 16-bit word relocation (020). */
256 HOWTO (R_RELWORD, /* type */
258 1, /* size (0 = byte, 1 = short, 2 = long) */
260 false, /* pc_relative */
262 complain_overflow_bitfield, /* complain_on_overflow */
263 coff_i386_reloc, /* special_function */
265 true, /* partial_inplace */
266 0x0000ffff, /* src_mask */
267 0x0000ffff, /* dst_mask */
268 PCRELOFFSET), /* pcrel_offset */
269 /* 32-bit longword relocation (021). */
270 HOWTO (R_RELLONG, /* type */
272 2, /* size (0 = byte, 1 = short, 2 = long) */
274 false, /* pc_relative */
276 complain_overflow_bitfield, /* complain_on_overflow */
277 coff_i386_reloc, /* special_function */
279 true, /* partial_inplace */
280 0xffffffff, /* src_mask */
281 0xffffffff, /* dst_mask */
282 PCRELOFFSET), /* pcrel_offset */
283 /* Byte PC relative relocation (022). */
284 HOWTO (R_PCRBYTE, /* type */
286 0, /* size (0 = byte, 1 = short, 2 = long) */
288 true, /* pc_relative */
290 complain_overflow_signed, /* complain_on_overflow */
291 coff_i386_reloc, /* special_function */
293 true, /* partial_inplace */
294 0x000000ff, /* src_mask */
295 0x000000ff, /* dst_mask */
296 PCRELOFFSET), /* pcrel_offset */
297 /* 16-bit word PC relative relocation (023). */
298 HOWTO (R_PCRWORD, /* type */
300 1, /* size (0 = byte, 1 = short, 2 = long) */
302 true, /* pc_relative */
304 complain_overflow_signed, /* complain_on_overflow */
305 coff_i386_reloc, /* special_function */
307 true, /* partial_inplace */
308 0x0000ffff, /* src_mask */
309 0x0000ffff, /* dst_mask */
310 PCRELOFFSET), /* pcrel_offset */
311 /* 32-bit longword PC relative relocation (024). */
312 HOWTO (R_PCRLONG, /* type */
314 2, /* size (0 = byte, 1 = short, 2 = long) */
316 true, /* pc_relative */
318 complain_overflow_signed, /* complain_on_overflow */
319 coff_i386_reloc, /* special_function */
321 true, /* partial_inplace */
322 0xffffffff, /* src_mask */
323 0xffffffff, /* dst_mask */
324 PCRELOFFSET) /* pcrel_offset */
327 /* Turn a howto into a reloc nunmber */
329 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
330 #define BADMAG(x) I386BADMAG(x)
331 #define I386 1 /* Customize coffcode.h */
333 #define RTYPE2HOWTO(cache_ptr, dst) \
334 ((cache_ptr)->howto = \
335 ((dst)->r_type < sizeof (howto_table) / sizeof (howto_table[0]) \
336 ? howto_table + (dst)->r_type \
339 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
340 library. On some other COFF targets STYP_BSS is normally
342 #define BSS_NOLOAD_IS_SHARED_LIBRARY
344 /* Compute the addend of a reloc. If the reloc is to a common symbol,
345 the object file contains the value of the common symbol. By the
346 time this is called, the linker may be using a different symbol
347 from a different object file with a different value. Therefore, we
348 hack wildly to locate the original symbol from this file so that we
349 can make the correct adjustment. This macro sets coffsym to the
350 symbol from the original file, and uses it to set the addend value
351 correctly. If this is not a common symbol, the usual addend
352 calculation is done, except that an additional tweak is needed for
354 FIXME: This macro refers to symbols and asect; these are from the
355 calling function, not the macro arguments. */
357 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
359 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
360 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
361 coffsym = (obj_symbols (abfd) \
362 + (cache_ptr->sym_ptr_ptr - symbols)); \
364 coffsym = coff_symbol_from (abfd, ptr); \
365 if (coffsym != (coff_symbol_type *) NULL \
366 && coffsym->native->u.syment.n_scnum == 0) \
367 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
368 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
369 && ptr->section != (asection *) NULL) \
370 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
372 cache_ptr->addend = 0; \
373 if (ptr && howto_table[reloc.r_type].pc_relative) \
374 cache_ptr->addend += asect->vma; \
377 /* We use the special COFF backend linker. For normal i386 COFF, we
378 can use the generic relocate_section routine. For PE, we need our
383 #define coff_relocate_section _bfd_coff_generic_relocate_section
385 #else /* COFF_WITH_PE */
387 /* The PE relocate section routine. The only difference between this
388 and the regular routine is that we don't want to do anything for a
389 relocateable link. */
391 static boolean coff_pe_i386_relocate_section
392 PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
393 struct internal_reloc *, struct internal_syment *, asection **));
396 coff_pe_i386_relocate_section (output_bfd, info, input_bfd,
397 input_section, contents, relocs, syms,
400 struct bfd_link_info *info;
402 asection *input_section;
404 struct internal_reloc *relocs;
405 struct internal_syment *syms;
408 if (info->relocateable)
411 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
412 input_section, contents,
413 relocs, syms, sections);
416 #define coff_relocate_section coff_pe_i386_relocate_section
418 #endif /* COFF_WITH_PE */
420 /* Convert an rtype to howto for the COFF backend linker. */
422 static reloc_howto_type *
423 coff_i386_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
424 bfd *abfd ATTRIBUTE_UNUSED;
426 struct internal_reloc *rel;
427 struct coff_link_hash_entry *h;
428 struct internal_syment *sym;
431 reloc_howto_type *howto;
433 if (rel->r_type > sizeof (howto_table) / sizeof (howto_table[0]))
435 bfd_set_error (bfd_error_bad_value);
439 howto = howto_table + rel->r_type;
442 /* Cancel out code in _bfd_coff_generic_relocate_section. */
446 if (howto->pc_relative)
447 *addendp += sec->vma;
449 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
451 /* This is a common symbol. The section contents include the
452 size (sym->n_value) as an addend. The relocate_section
453 function will be adding in the final value of the symbol. We
454 need to subtract out the current size in order to get the
457 BFD_ASSERT (h != NULL);
460 /* I think we *do* want to bypass this. If we don't, I have
461 seen some data parameters get the wrong relocation address.
462 If I link two versions with and without this section bypassed
463 and then do a binary comparison, the addresses which are
464 different can be looked up in the map. The case in which
465 this section has been bypassed has addresses which correspond
466 to values I can find in the map. */
467 *addendp -= sym->n_value;
472 /* If the output symbol is common (in which case this must be a
473 relocateable link), we need to add in the final size of the
475 if (h != NULL && h->root.type == bfd_link_hash_common)
476 *addendp += h->root.u.c.size;
480 if (howto->pc_relative)
484 /* If the symbol is defined, then the generic code is going to
485 add back the symbol value in order to cancel out an
486 adjustment it made to the addend. However, we set the addend
487 to 0 at the start of this function. We need to adjust here,
488 to avoid the adjustment the generic code will make. FIXME:
489 This is getting a bit hackish. */
490 if (sym != NULL && sym->n_scnum != 0)
491 *addendp -= sym->n_value;
494 if (rel->r_type == R_IMAGEBASE
495 && (bfd_get_flavour(sec->output_section->owner)
496 == bfd_target_coff_flavour))
498 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
505 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
507 static reloc_howto_type *
508 coff_i386_reloc_type_lookup (abfd, code)
509 bfd *abfd ATTRIBUTE_UNUSED;
510 bfd_reloc_code_real_type code;
515 return howto_table + R_IMAGEBASE;
517 return howto_table + R_DIR32;
518 case BFD_RELOC_32_PCREL:
519 return howto_table + R_PCRLONG;
521 return howto_table + R_RELWORD;
522 case BFD_RELOC_16_PCREL:
523 return howto_table + R_PCRWORD;
525 return howto_table + R_RELBYTE;
526 case BFD_RELOC_8_PCREL:
527 return howto_table + R_PCRBYTE;
534 #define coff_rtype_to_howto coff_i386_rtype_to_howto
536 #ifdef TARGET_UNDERSCORE
538 /* If i386 gcc uses underscores for symbol names, then it does not use
539 a leading dot for local labels, so if TARGET_UNDERSCORE is defined
540 we treat all symbols starting with L as local. */
542 static boolean coff_i386_is_local_label_name PARAMS ((bfd *, const char *));
545 coff_i386_is_local_label_name (abfd, name)
552 return _bfd_coff_is_local_label_name (abfd, name);
555 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
557 #endif /* TARGET_UNDERSCORE */
559 #include "coffcode.h"
571 "coff-i386", /* name */
573 bfd_target_coff_flavour,
574 BFD_ENDIAN_LITTLE, /* data byte order is little */
575 BFD_ENDIAN_LITTLE, /* header byte order is little */
577 (HAS_RELOC | EXEC_P | /* object flags */
578 HAS_LINENO | HAS_DEBUG |
579 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED),
581 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
583 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY
585 | SEC_CODE | SEC_DATA),
587 #ifdef TARGET_UNDERSCORE
588 TARGET_UNDERSCORE, /* leading underscore */
590 0, /* leading underscore */
592 '/', /* ar_pad_char */
593 15, /* ar_max_namelen */
595 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
596 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
597 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
598 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
599 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
600 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
602 /* Note that we allow an object file to be treated as a core file as well. */
603 {_bfd_dummy_target, coff_object_p, /* bfd_check_format */
604 bfd_generic_archive_p, coff_object_p},
605 {bfd_false, coff_mkobject, _bfd_generic_mkarchive, /* bfd_set_format */
607 {bfd_false, coff_write_object_contents, /* bfd_write_contents */
608 _bfd_write_archive_contents, bfd_false},
610 BFD_JUMP_TABLE_GENERIC (coff),
611 BFD_JUMP_TABLE_COPY (coff),
612 BFD_JUMP_TABLE_CORE (_bfd_nocore),
613 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
614 BFD_JUMP_TABLE_SYMBOLS (coff),
615 BFD_JUMP_TABLE_RELOCS (coff),
616 BFD_JUMP_TABLE_WRITE (coff),
617 BFD_JUMP_TABLE_LINK (coff),
618 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),