1 /* BFD back-end for Intel 386 COFF files.
2 Copyright (C) 1990-2018 Free Software Foundation, Inc.
3 Written by Cygnus Support.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
26 #include "coff/i386.h"
28 #include "coff/internal.h"
35 #include "coff/go32exe.h"
38 #ifndef bfd_pe_print_pdata
39 #define bfd_pe_print_pdata NULL
44 static reloc_howto_type *coff_i386_rtype_to_howto
45 (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 (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 (bfd *abfd,
70 asection *input_section ATTRIBUTE_UNUSED,
72 char **error_message ATTRIBUTE_UNUSED)
77 if (output_bfd == (bfd *) NULL)
78 return bfd_reloc_continue;
81 if (bfd_is_com_section (symbol->section))
84 /* We are relocating a common symbol. The current value in the
85 object file is ORIG + OFFSET, where ORIG is the value of the
86 common symbol as seen by the object file when it was compiled
87 (this may be zero if the symbol was undefined) and OFFSET is
88 the offset into the common symbol (normally zero, but may be
89 non-zero when referring to a field in a common structure).
90 ORIG is the negative of reloc_entry->addend, which is set by
91 the CALC_ADDEND macro below. We want to replace the value in
92 the object file with NEW + OFFSET, where NEW is the value of
93 the common symbol which we are going to put in the final
94 object file. NEW is symbol->value. */
95 diff = symbol->value + reloc_entry->addend;
97 /* In PE mode, we do not offset the common symbol. */
98 diff = reloc_entry->addend;
103 /* For some reason bfd_perform_relocation always effectively
104 ignores the addend for a COFF target when producing
105 relocatable output. This seems to be always wrong for 386
106 COFF, so we handle the addend here instead. */
108 if (output_bfd == (bfd *) NULL)
110 reloc_howto_type *howto = reloc_entry->howto;
112 /* Although PC relative relocations are very similar between
113 PE and non-PE formats, but they are off by 1 << howto->size
114 bytes. For the external relocation, PE is very different
115 from others. See md_apply_fix3 () in gas/config/tc-i386.c.
116 When we link PE and non-PE object files together to
117 generate a non-PE executable, we have to compensate it
119 if (howto->pc_relative && howto->pcrel_offset)
120 diff = -(1 << howto->size);
121 else if (symbol->flags & BSF_WEAK)
122 diff = reloc_entry->addend - symbol->value;
124 diff = -reloc_entry->addend;
128 diff = reloc_entry->addend;
132 /* FIXME: How should this case be handled? */
133 if (reloc_entry->howto->type == R_IMAGEBASE
134 && output_bfd != NULL
135 && bfd_get_flavour(output_bfd) == bfd_target_coff_flavour)
136 diff -= pe_data (output_bfd)->pe_opthdr.ImageBase;
140 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
144 reloc_howto_type *howto = reloc_entry->howto;
145 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
147 if (! bfd_reloc_offset_in_range (howto, abfd, input_section,
149 * bfd_octets_per_byte (abfd)))
150 return bfd_reloc_outofrange;
156 char x = bfd_get_8 (abfd, addr);
158 bfd_put_8 (abfd, x, addr);
164 short x = bfd_get_16 (abfd, addr);
166 bfd_put_16 (abfd, (bfd_vma) x, addr);
172 long x = bfd_get_32 (abfd, addr);
174 bfd_put_32 (abfd, (bfd_vma) x, addr);
183 /* Now let bfd_perform_relocation finish everything up. */
184 return bfd_reloc_continue;
188 /* Return TRUE if this relocation should appear in the output .reloc
191 static bfd_boolean in_reloc_p (bfd * abfd ATTRIBUTE_UNUSED,
192 reloc_howto_type *howto)
194 return ! howto->pc_relative && howto->type != R_IMAGEBASE
195 && howto->type != R_SECREL32;
197 #endif /* COFF_WITH_PE */
200 #define PCRELOFFSET FALSE
203 static reloc_howto_type howto_table[] =
211 HOWTO (R_DIR32, /* type */
213 2, /* size (0 = byte, 1 = short, 2 = long) */
215 FALSE, /* pc_relative */
217 complain_overflow_bitfield, /* complain_on_overflow */
218 coff_i386_reloc, /* special_function */
220 TRUE, /* partial_inplace */
221 0xffffffff, /* src_mask */
222 0xffffffff, /* dst_mask */
223 TRUE), /* pcrel_offset */
224 /* PE IMAGE_REL_I386_DIR32NB relocation (7). */
225 HOWTO (R_IMAGEBASE, /* type */
227 2, /* size (0 = byte, 1 = short, 2 = long) */
229 FALSE, /* pc_relative */
231 complain_overflow_bitfield, /* complain_on_overflow */
232 coff_i386_reloc, /* special_function */
234 TRUE, /* partial_inplace */
235 0xffffffff, /* src_mask */
236 0xffffffff, /* dst_mask */
237 FALSE), /* pcrel_offset */
242 /* 32-bit longword section relative relocation (013). */
243 HOWTO (R_SECREL32, /* type */
245 2, /* size (0 = byte, 1 = short, 2 = long) */
247 FALSE, /* pc_relative */
249 complain_overflow_bitfield, /* complain_on_overflow */
250 coff_i386_reloc, /* special_function */
251 "secrel32", /* name */
252 TRUE, /* partial_inplace */
253 0xffffffff, /* src_mask */
254 0xffffffff, /* dst_mask */
255 TRUE), /* pcrel_offset */
262 /* Byte relocation (017). */
263 HOWTO (R_RELBYTE, /* type */
265 0, /* size (0 = byte, 1 = short, 2 = long) */
267 FALSE, /* pc_relative */
269 complain_overflow_bitfield, /* complain_on_overflow */
270 coff_i386_reloc, /* special_function */
272 TRUE, /* partial_inplace */
273 0x000000ff, /* src_mask */
274 0x000000ff, /* dst_mask */
275 PCRELOFFSET), /* pcrel_offset */
276 /* 16-bit word relocation (020). */
277 HOWTO (R_RELWORD, /* type */
279 1, /* size (0 = byte, 1 = short, 2 = long) */
281 FALSE, /* pc_relative */
283 complain_overflow_bitfield, /* complain_on_overflow */
284 coff_i386_reloc, /* special_function */
286 TRUE, /* partial_inplace */
287 0x0000ffff, /* src_mask */
288 0x0000ffff, /* dst_mask */
289 PCRELOFFSET), /* pcrel_offset */
290 /* 32-bit longword relocation (021). */
291 HOWTO (R_RELLONG, /* type */
293 2, /* size (0 = byte, 1 = short, 2 = long) */
295 FALSE, /* pc_relative */
297 complain_overflow_bitfield, /* complain_on_overflow */
298 coff_i386_reloc, /* special_function */
300 TRUE, /* partial_inplace */
301 0xffffffff, /* src_mask */
302 0xffffffff, /* dst_mask */
303 PCRELOFFSET), /* pcrel_offset */
304 /* Byte PC relative relocation (022). */
305 HOWTO (R_PCRBYTE, /* type */
307 0, /* size (0 = byte, 1 = short, 2 = long) */
309 TRUE, /* pc_relative */
311 complain_overflow_signed, /* complain_on_overflow */
312 coff_i386_reloc, /* special_function */
314 TRUE, /* partial_inplace */
315 0x000000ff, /* src_mask */
316 0x000000ff, /* dst_mask */
317 PCRELOFFSET), /* pcrel_offset */
318 /* 16-bit word PC relative relocation (023). */
319 HOWTO (R_PCRWORD, /* type */
321 1, /* size (0 = byte, 1 = short, 2 = long) */
323 TRUE, /* pc_relative */
325 complain_overflow_signed, /* complain_on_overflow */
326 coff_i386_reloc, /* special_function */
328 TRUE, /* partial_inplace */
329 0x0000ffff, /* src_mask */
330 0x0000ffff, /* dst_mask */
331 PCRELOFFSET), /* pcrel_offset */
332 /* 32-bit longword PC relative relocation (024). */
333 HOWTO (R_PCRLONG, /* type */
335 2, /* size (0 = byte, 1 = short, 2 = long) */
337 TRUE, /* pc_relative */
339 complain_overflow_signed, /* complain_on_overflow */
340 coff_i386_reloc, /* special_function */
342 TRUE, /* partial_inplace */
343 0xffffffff, /* src_mask */
344 0xffffffff, /* dst_mask */
345 PCRELOFFSET) /* pcrel_offset */
348 #define NUM_HOWTOS (sizeof (howto_table) / sizeof (howto_table[0]))
350 /* Turn a howto into a reloc nunmber */
352 #define SELECT_RELOC(x,howto) { x.r_type = howto->type; }
353 #define BADMAG(x) I386BADMAG(x)
354 #define I386 1 /* Customize coffcode.h */
356 #define RTYPE2HOWTO(cache_ptr, dst) \
357 ((cache_ptr)->howto = \
358 ((dst)->r_type < NUM_HOWTOS \
359 ? howto_table + (dst)->r_type \
362 /* For 386 COFF a STYP_NOLOAD | STYP_BSS section is part of a shared
363 library. On some other COFF targets STYP_BSS is normally
365 #define BSS_NOLOAD_IS_SHARED_LIBRARY
367 /* Compute the addend of a reloc. If the reloc is to a common symbol,
368 the object file contains the value of the common symbol. By the
369 time this is called, the linker may be using a different symbol
370 from a different object file with a different value. Therefore, we
371 hack wildly to locate the original symbol from this file so that we
372 can make the correct adjustment. This macro sets coffsym to the
373 symbol from the original file, and uses it to set the addend value
374 correctly. If this is not a common symbol, the usual addend
375 calculation is done, except that an additional tweak is needed for
377 FIXME: This macro refers to symbols and asect; these are from the
378 calling function, not the macro arguments. */
380 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
382 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
383 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
384 coffsym = (obj_symbols (abfd) \
385 + (cache_ptr->sym_ptr_ptr - symbols)); \
387 coffsym = coff_symbol_from (ptr); \
388 if (coffsym != (coff_symbol_type *) NULL \
389 && coffsym->native->u.syment.n_scnum == 0) \
390 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
391 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
392 && ptr->section != (asection *) NULL) \
393 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
395 cache_ptr->addend = 0; \
396 if (ptr && reloc.r_type < NUM_HOWTOS \
397 && howto_table[reloc.r_type].pc_relative) \
398 cache_ptr->addend += asect->vma; \
401 /* We use the special COFF backend linker. For normal i386 COFF, we
402 can use the generic relocate_section routine. For PE, we need our
407 #define coff_relocate_section _bfd_coff_generic_relocate_section
409 #else /* COFF_WITH_PE */
411 /* The PE relocate section routine. The only difference between this
412 and the regular routine is that we don't want to do anything for a
416 coff_pe_i386_relocate_section (bfd *output_bfd,
417 struct bfd_link_info *info,
419 asection *input_section,
421 struct internal_reloc *relocs,
422 struct internal_syment *syms,
425 if (bfd_link_relocatable (info))
428 return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
429 input_section, contents,
430 relocs, syms, sections);
433 #define coff_relocate_section coff_pe_i386_relocate_section
435 #endif /* COFF_WITH_PE */
437 /* Convert an rtype to howto for the COFF backend linker. */
439 static reloc_howto_type *
440 coff_i386_rtype_to_howto (bfd *abfd ATTRIBUTE_UNUSED,
442 struct internal_reloc *rel,
443 struct coff_link_hash_entry *h,
444 struct internal_syment *sym,
447 reloc_howto_type *howto;
449 if (rel->r_type >= NUM_HOWTOS)
451 bfd_set_error (bfd_error_bad_value);
455 howto = howto_table + rel->r_type;
458 /* Cancel out code in _bfd_coff_generic_relocate_section. */
462 if (howto->pc_relative)
463 *addendp += sec->vma;
465 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
467 /* This is a common symbol. The section contents include the
468 size (sym->n_value) as an addend. The relocate_section
469 function will be adding in the final value of the symbol. We
470 need to subtract out the current size in order to get the
473 BFD_ASSERT (h != NULL);
476 /* I think we *do* want to bypass this. If we don't, I have
477 seen some data parameters get the wrong relocation address.
478 If I link two versions with and without this section bypassed
479 and then do a binary comparison, the addresses which are
480 different can be looked up in the map. The case in which
481 this section has been bypassed has addresses which correspond
482 to values I can find in the map. */
483 *addendp -= sym->n_value;
488 /* If the output symbol is common (in which case this must be a
489 relocatable link), we need to add in the final size of the
491 if (h != NULL && h->root.type == bfd_link_hash_common)
492 *addendp += h->root.u.c.size;
496 if (howto->pc_relative)
500 /* If the symbol is defined, then the generic code is going to
501 add back the symbol value in order to cancel out an
502 adjustment it made to the addend. However, we set the addend
503 to 0 at the start of this function. We need to adjust here,
504 to avoid the adjustment the generic code will make. FIXME:
505 This is getting a bit hackish. */
506 if (sym != NULL && sym->n_scnum != 0)
507 *addendp -= sym->n_value;
510 if (rel->r_type == R_IMAGEBASE
511 && (bfd_get_flavour(sec->output_section->owner)
512 == bfd_target_coff_flavour))
514 *addendp -= pe_data(sec->output_section->owner)->pe_opthdr.ImageBase;
517 /* PR 17099 - Absolute R_PCRLONG relocations do not need a symbol. */
518 if (rel->r_type == R_PCRLONG && sym == NULL)
519 *addendp -= rel->r_vaddr;
521 BFD_ASSERT (sym != NULL);
523 if (rel->r_type == R_SECREL32 && sym != NULL)
527 if (h && (h->root.type == bfd_link_hash_defined
528 || h->root.type == bfd_link_hash_defweak))
529 osect_vma = h->root.u.def.section->output_section->vma;
535 /* Sigh, the only way to get the section to offset against
536 is to find it the hard way. */
538 for (s = abfd->sections, i = 1; i < sym->n_scnum; i++)
541 osect_vma = s->output_section->vma;
544 *addendp -= osect_vma;
551 #define coff_bfd_reloc_type_lookup coff_i386_reloc_type_lookup
552 #define coff_bfd_reloc_name_lookup coff_i386_reloc_name_lookup
554 static reloc_howto_type *
555 coff_i386_reloc_type_lookup (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 < NUM_HOWTOS; 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. */
607 coff_i386_is_local_label_name (bfd *abfd, const char *name)
612 return _bfd_coff_is_local_label_name (abfd, name);
615 #define coff_bfd_is_local_label_name coff_i386_is_local_label_name
617 #endif /* TARGET_UNDERSCORE */
619 #include "coffcode.h"
631 "coff-i386", /* name */
633 bfd_target_coff_flavour,
634 BFD_ENDIAN_LITTLE, /* data byte order is little */
635 BFD_ENDIAN_LITTLE, /* header byte order is little */
637 (HAS_RELOC | EXEC_P | /* object flags */
638 HAS_LINENO | HAS_DEBUG |
639 HAS_SYMS | HAS_LOCALS | WP_TEXT | D_PAGED | BFD_COMPRESS | BFD_DECOMPRESS ),
641 (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC /* section flags */
643 | SEC_LINK_ONCE | SEC_LINK_DUPLICATES | SEC_READONLY | SEC_DEBUGGING
645 | SEC_CODE | SEC_DATA | SEC_EXCLUDE ),
647 #ifdef TARGET_UNDERSCORE
648 TARGET_UNDERSCORE, /* leading underscore */
650 0, /* leading underscore */
652 '/', /* ar_pad_char */
653 15, /* ar_max_namelen */
654 0, /* match priority. */
656 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
657 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
658 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* data */
659 bfd_getl64, bfd_getl_signed_64, bfd_putl64,
660 bfd_getl32, bfd_getl_signed_32, bfd_putl32,
661 bfd_getl16, bfd_getl_signed_16, bfd_putl16, /* hdrs */
663 /* Note that we allow an object file to be treated as a core file as well. */
665 #ifdef COFF_CHECK_FORMAT
666 { /* bfd_check_format */
669 bfd_generic_archive_p,
676 bfd_generic_archive_p,
680 { /* bfd_set_format */
681 _bfd_bool_bfd_false_error,
683 _bfd_generic_mkarchive,
684 _bfd_bool_bfd_false_error
686 { /* bfd_write_contents */
687 _bfd_bool_bfd_false_error,
688 coff_write_object_contents,
689 _bfd_write_archive_contents,
690 _bfd_bool_bfd_false_error
693 BFD_JUMP_TABLE_GENERIC (coff),
694 BFD_JUMP_TABLE_COPY (coff),
695 BFD_JUMP_TABLE_CORE (_bfd_nocore),
696 BFD_JUMP_TABLE_ARCHIVE (_bfd_archive_coff),
697 BFD_JUMP_TABLE_SYMBOLS (coff),
698 BFD_JUMP_TABLE_RELOCS (coff),
699 BFD_JUMP_TABLE_WRITE (coff),
700 BFD_JUMP_TABLE_LINK (coff),
701 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),