1 /* BFD back-end for Motorola 68000 COFF binaries.
2 Copyright (C) 1990-2014 Free Software Foundation, Inc.
3 Written by Cygnus Support.
4
5 This file is part of BFD, the Binary File Descriptor library.
6
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.
11
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.
16
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. */
21
22 #include "sysdep.h"
23 #include "bfd.h"
24 #include "libbfd.h"
25 #include "coff/m68k.h"
26 #include "coff/internal.h"
27 #include "libcoff.h"
28
29 /* This source file is compiled multiple times for various m68k COFF
30 variants. The following macros control its behaviour:
31
32 TARGET_SYM
33 The C name of the BFD target vector. The default is m68k_coff_vec.
34 TARGET_NAME
35 The user visible target name. The default is "coff-m68k".
36 NAMES_HAVE_UNDERSCORE
37 Whether symbol names have an underscore.
38 ONLY_DECLARE_RELOCS
39 Only declare the relocation howto array. Don't actually compile
40 it. The actual array will be picked up in another version of the
41 file.
42 STATIC_RELOCS
43 Make the relocation howto array, and associated functions, static.
44 COFF_COMMON_ADDEND
45 If this is defined, then, for a relocation against a common
46 symbol, the object file holds the value (the size) of the common
47 symbol. If this is not defined, then, for a relocation against a
48 common symbol, the object file holds zero. */
49
50 #define COFF_DEFAULT_SECTION_ALIGNMENT_POWER (2)
51
52 #ifndef COFF_PAGE_SIZE
53 /* The page size is a guess based on ELF. */
54 #define COFF_PAGE_SIZE 0x2000
55 #endif
56
57 #ifndef COFF_COMMON_ADDEND
58 #define RELOC_SPECIAL_FN 0
59 #else
60 static bfd_reloc_status_type m68kcoff_common_addend_special_fn
61 (bfd *, arelent *, asymbol *, void *, asection *, bfd *, char **);
62
63 #define RELOC_SPECIAL_FN m68kcoff_common_addend_special_fn
64 #endif
65
66 static bfd_boolean m68k_coff_is_local_label_name (bfd *, const char *);
67
68 /* On the delta, a symbol starting with L% is local. We won't see
69 such a symbol on other platforms, so it should be safe to always
70 consider it local here. */
71
72 static bfd_boolean
m68k_coff_is_local_label_name(bfd * abfd,const char * name)73 m68k_coff_is_local_label_name (bfd *abfd, const char *name)
74 {
75 if (name[0] == 'L' && name[1] == '%')
76 return TRUE;
77
78 return _bfd_coff_is_local_label_name (abfd, name);
79 }
80
81 #ifndef STATIC_RELOCS
82 /* Clean up namespace. */
83 #define m68kcoff_howto_table _bfd_m68kcoff_howto_table
84 #define m68k_rtype2howto _bfd_m68kcoff_rtype2howto
85 #define m68k_howto2rtype _bfd_m68kcoff_howto2rtype
86 #define m68k_reloc_type_lookup _bfd_m68kcoff_reloc_type_lookup
87 #define m68k_reloc_name_lookup _bfd_m68kcoff_reloc_name_lookup
88 #endif
89
90 #ifdef ONLY_DECLARE_RELOCS
91 extern reloc_howto_type m68kcoff_howto_table[];
92 #else
93 #ifdef STATIC_RELOCS
94 static
95 #endif
96 reloc_howto_type m68kcoff_howto_table[] =
97 {
98 HOWTO (R_RELBYTE, 0, 0, 8, FALSE, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "8", TRUE, 0x000000ff,0x000000ff, FALSE),
99 HOWTO (R_RELWORD, 0, 1, 16, FALSE, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "16", TRUE, 0x0000ffff,0x0000ffff, FALSE),
100 HOWTO (R_RELLONG, 0, 2, 32, FALSE, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "32", TRUE, 0xffffffff,0xffffffff, FALSE),
101 HOWTO (R_PCRBYTE, 0, 0, 8, TRUE, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP8", TRUE, 0x000000ff,0x000000ff, FALSE),
102 HOWTO (R_PCRWORD, 0, 1, 16, TRUE, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP16", TRUE, 0x0000ffff,0x0000ffff, FALSE),
103 HOWTO (R_PCRLONG, 0, 2, 32, TRUE, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP32", TRUE, 0xffffffff,0xffffffff, FALSE),
104 HOWTO (R_RELLONG_NEG, 0, -2, 32, FALSE, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "-32", TRUE, 0xffffffff,0xffffffff, FALSE),
105 };
106 #endif /* not ONLY_DECLARE_RELOCS */
107
108 #ifndef BADMAG
109 #define BADMAG(x) M68KBADMAG(x)
110 #endif
111 #define M68 1 /* Customize coffcode.h */
112
113 /* Turn a howto into a reloc number */
114
115 #ifdef ONLY_DECLARE_RELOCS
116 extern void m68k_rtype2howto (arelent *internal, int relocentry);
117 extern int m68k_howto2rtype (reloc_howto_type *);
118 extern reloc_howto_type * m68k_reloc_type_lookup
119 (bfd *, bfd_reloc_code_real_type);
120 extern reloc_howto_type * m68k_reloc_name_lookup (bfd *, const char *);
121 #else
122
123 #ifdef STATIC_RELOCS
124 #define STAT_REL static
125 #else
126 #define STAT_REL
127 #endif
128
129 STAT_REL void m68k_rtype2howto (arelent *, int);
130 STAT_REL int m68k_howto2rtype (reloc_howto_type *);
131 STAT_REL reloc_howto_type * m68k_reloc_type_lookup (bfd *, bfd_reloc_code_real_type);
132 STAT_REL reloc_howto_type * m68k_reloc_name_lookup (bfd *, const char *);
133
134 STAT_REL void
m68k_rtype2howto(arelent * internal,int relocentry)135 m68k_rtype2howto (arelent *internal, int relocentry)
136 {
137 switch (relocentry)
138 {
139 case R_RELBYTE: internal->howto = m68kcoff_howto_table + 0; break;
140 case R_RELWORD: internal->howto = m68kcoff_howto_table + 1; break;
141 case R_RELLONG: internal->howto = m68kcoff_howto_table + 2; break;
142 case R_PCRBYTE: internal->howto = m68kcoff_howto_table + 3; break;
143 case R_PCRWORD: internal->howto = m68kcoff_howto_table + 4; break;
144 case R_PCRLONG: internal->howto = m68kcoff_howto_table + 5; break;
145 case R_RELLONG_NEG: internal->howto = m68kcoff_howto_table + 6; break;
146 }
147 }
148
149 STAT_REL int
m68k_howto2rtype(reloc_howto_type * internal)150 m68k_howto2rtype (reloc_howto_type * internal)
151 {
152 if (internal->pc_relative)
153 {
154 switch (internal->bitsize)
155 {
156 case 32: return R_PCRLONG;
157 case 16: return R_PCRWORD;
158 case 8: return R_PCRBYTE;
159 }
160 }
161 else
162 {
163 switch (internal->bitsize)
164 {
165 case 32: return R_RELLONG;
166 case 16: return R_RELWORD;
167 case 8: return R_RELBYTE;
168 }
169 }
170 return R_RELLONG;
171 }
172
173 STAT_REL reloc_howto_type *
m68k_reloc_type_lookup(bfd * abfd ATTRIBUTE_UNUSED,bfd_reloc_code_real_type code)174 m68k_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
175 bfd_reloc_code_real_type code)
176 {
177 switch (code)
178 {
179 default: return NULL;
180 case BFD_RELOC_8: return m68kcoff_howto_table + 0;
181 case BFD_RELOC_16: return m68kcoff_howto_table + 1;
182 case BFD_RELOC_CTOR:
183 case BFD_RELOC_32: return m68kcoff_howto_table + 2;
184 case BFD_RELOC_8_PCREL: return m68kcoff_howto_table + 3;
185 case BFD_RELOC_16_PCREL: return m68kcoff_howto_table + 4;
186 case BFD_RELOC_32_PCREL: return m68kcoff_howto_table + 5;
187 /* FIXME: There doesn't seem to be a code for R_RELLONG_NEG. */
188 }
189 /*NOTREACHED*/
190 }
191
192 STAT_REL reloc_howto_type *
m68k_reloc_name_lookup(bfd * abfd ATTRIBUTE_UNUSED,const char * r_name)193 m68k_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
194 const char *r_name)
195 {
196 unsigned int i;
197
198 for (i = 0;
199 i < sizeof (m68kcoff_howto_table) / sizeof (m68kcoff_howto_table[0]);
200 i++)
201 if (m68kcoff_howto_table[i].name != NULL
202 && strcasecmp (m68kcoff_howto_table[i].name, r_name) == 0)
203 return &m68kcoff_howto_table[i];
204
205 return NULL;
206 }
207
208 #endif /* not ONLY_DECLARE_RELOCS */
209
210 #define RTYPE2HOWTO(internal, relocentry) \
211 m68k_rtype2howto(internal, (relocentry)->r_type)
212
213 #define SELECT_RELOC(external, internal) \
214 external.r_type = m68k_howto2rtype (internal)
215
216 #define coff_bfd_reloc_type_lookup m68k_reloc_type_lookup
217 #define coff_bfd_reloc_name_lookup m68k_reloc_name_lookup
218
219 #ifndef COFF_COMMON_ADDEND
220 #ifndef coff_rtype_to_howto
221
222 #define coff_rtype_to_howto m68kcoff_rtype_to_howto
223
224 static reloc_howto_type *
m68kcoff_rtype_to_howto(bfd * abfd ATTRIBUTE_UNUSED,asection * sec,struct internal_reloc * rel,struct coff_link_hash_entry * h ATTRIBUTE_UNUSED,struct internal_syment * sym ATTRIBUTE_UNUSED,bfd_vma * addendp)225 m68kcoff_rtype_to_howto (bfd *abfd ATTRIBUTE_UNUSED,
226 asection *sec,
227 struct internal_reloc *rel,
228 struct coff_link_hash_entry *h ATTRIBUTE_UNUSED,
229 struct internal_syment *sym ATTRIBUTE_UNUSED,
230 bfd_vma *addendp)
231 {
232 arelent relent;
233 reloc_howto_type *howto;
234
235 relent.howto = NULL;
236 RTYPE2HOWTO (&relent, rel);
237
238 howto = relent.howto;
239
240 if (howto != NULL && howto->pc_relative)
241 *addendp += sec->vma;
242
243 return howto;
244 }
245
246 #endif /* ! defined (coff_rtype_to_howto) */
247 #endif /* ! defined (COFF_COMMON_ADDEND) */
248
249 #ifdef COFF_COMMON_ADDEND
250
251 /* If COFF_COMMON_ADDEND is defined, then when using m68k COFF the
252 value stored in the .text section for a reference to a common
253 symbol is the value itself plus any desired offset. (taken from
254 work done by Ian Taylor, Cygnus Support, for I386 COFF). */
255
256 /* If we are producing relocatable output, we need to do some
257 adjustments to the object file that are not done by the
258 bfd_perform_relocation function. This function is called by every
259 reloc type to make any required adjustments. */
260
261 static bfd_reloc_status_type
m68kcoff_common_addend_special_fn(bfd * abfd,arelent * reloc_entry,asymbol * symbol,void * data,asection * input_section ATTRIBUTE_UNUSED,bfd * output_bfd,char ** error_message ATTRIBUTE_UNUSED)262 m68kcoff_common_addend_special_fn (bfd *abfd,
263 arelent *reloc_entry,
264 asymbol *symbol,
265 void * data,
266 asection *input_section ATTRIBUTE_UNUSED,
267 bfd *output_bfd,
268 char **error_message ATTRIBUTE_UNUSED)
269 {
270 symvalue diff;
271
272 if (output_bfd == (bfd *) NULL)
273 return bfd_reloc_continue;
274
275 if (bfd_is_com_section (symbol->section))
276 {
277 /* We are relocating a common symbol. The current value in the
278 object file is ORIG + OFFSET, where ORIG is the value of the
279 common symbol as seen by the object file when it was compiled
280 (this may be zero if the symbol was undefined) and OFFSET is
281 the offset into the common symbol (normally zero, but may be
282 non-zero when referring to a field in a common structure).
283 ORIG is the negative of reloc_entry->addend, which is set by
284 the CALC_ADDEND macro below. We want to replace the value in
285 the object file with NEW + OFFSET, where NEW is the value of
286 the common symbol which we are going to put in the final
287 object file. NEW is symbol->value. */
288 diff = symbol->value + reloc_entry->addend;
289 }
290 else
291 {
292 /* For some reason bfd_perform_relocation always effectively
293 ignores the addend for a COFF target when producing
294 relocatable output. This seems to be always wrong for 386
295 COFF, so we handle the addend here instead. */
296 diff = reloc_entry->addend;
297 }
298
299 #define DOIT(x) \
300 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
301
302 if (diff != 0)
303 {
304 reloc_howto_type *howto = reloc_entry->howto;
305 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
306
307 switch (howto->size)
308 {
309 case 0:
310 {
311 char x = bfd_get_8 (abfd, addr);
312 DOIT (x);
313 bfd_put_8 (abfd, x, addr);
314 }
315 break;
316
317 case 1:
318 {
319 short x = bfd_get_16 (abfd, addr);
320 DOIT (x);
321 bfd_put_16 (abfd, (bfd_vma) x, addr);
322 }
323 break;
324
325 case 2:
326 {
327 long x = bfd_get_32 (abfd, addr);
328 DOIT (x);
329 bfd_put_32 (abfd, (bfd_vma) x, addr);
330 }
331 break;
332
333 default:
334 abort ();
335 }
336 }
337
338 /* Now let bfd_perform_relocation finish everything up. */
339 return bfd_reloc_continue;
340 }
341
342 /* Compute the addend of a reloc. If the reloc is to a common symbol,
343 the object file contains the value of the common symbol. By the
344 time this is called, the linker may be using a different symbol
345 from a different object file with a different value. Therefore, we
346 hack wildly to locate the original symbol from this file so that we
347 can make the correct adjustment. This macro sets coffsym to the
348 symbol from the original file, and uses it to set the addend value
349 correctly. If this is not a common symbol, the usual addend
350 calculation is done, except that an additional tweak is needed for
351 PC relative relocs.
352 FIXME: This macro refers to symbols and asect; these are from the
353 calling function, not the macro arguments. */
354
355 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
356 { \
357 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
358 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
359 coffsym = (obj_symbols (abfd) \
360 + (cache_ptr->sym_ptr_ptr - symbols)); \
361 else if (ptr) \
362 coffsym = coff_symbol_from (abfd, ptr); \
363 if (coffsym != (coff_symbol_type *) NULL \
364 && coffsym->native->u.syment.n_scnum == 0) \
365 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
366 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
367 && ptr->section != (asection *) NULL) \
368 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
369 else \
370 cache_ptr->addend = 0; \
371 if (ptr && (reloc.r_type == R_PCRBYTE \
372 || reloc.r_type == R_PCRWORD \
373 || reloc.r_type == R_PCRLONG)) \
374 cache_ptr->addend += asect->vma; \
375 }
376
377 #ifndef coff_rtype_to_howto
378
379 /* coff-m68k.c uses the special COFF backend linker. We need to
380 adjust common symbols. */
381
382 static reloc_howto_type *
m68kcoff_common_addend_rtype_to_howto(bfd * abfd ATTRIBUTE_UNUSED,asection * sec,struct internal_reloc * rel,struct coff_link_hash_entry * h,struct internal_syment * sym,bfd_vma * addendp)383 m68kcoff_common_addend_rtype_to_howto (bfd *abfd ATTRIBUTE_UNUSED,
384 asection *sec,
385 struct internal_reloc *rel,
386 struct coff_link_hash_entry *h,
387 struct internal_syment *sym,
388 bfd_vma *addendp)
389 {
390 arelent relent;
391 reloc_howto_type *howto;
392
393 relent.howto = NULL;
394 RTYPE2HOWTO (&relent, rel);
395
396 howto = relent.howto;
397
398 if (howto->pc_relative)
399 *addendp += sec->vma;
400
401 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
402 {
403 /* This is a common symbol. The section contents include the
404 size (sym->n_value) as an addend. The relocate_section
405 function will be adding in the final value of the symbol. We
406 need to subtract out the current size in order to get the
407 correct result. */
408 BFD_ASSERT (h != NULL);
409 *addendp -= sym->n_value;
410 }
411
412 /* If the output symbol is common (in which case this must be a
413 relocatable link), we need to add in the final size of the
414 common symbol. */
415 if (h != NULL && h->root.type == bfd_link_hash_common)
416 *addendp += h->root.u.c.size;
417
418 return howto;
419 }
420
421 #define coff_rtype_to_howto m68kcoff_common_addend_rtype_to_howto
422
423 #endif /* ! defined (coff_rtype_to_howto) */
424
425 #endif /* COFF_COMMON_ADDEND */
426
427 #if !defined ONLY_DECLARE_RELOCS && ! defined STATIC_RELOCS
428 /* Given a .data section and a .emreloc in-memory section, store
429 relocation information into the .emreloc section which can be
430 used at runtime to relocate the section. This is called by the
431 linker when the --embedded-relocs switch is used. This is called
432 after the add_symbols entry point has been called for all the
433 objects, and before the final_link entry point is called. */
434
435 bfd_boolean
bfd_m68k_coff_create_embedded_relocs(bfd * abfd,struct bfd_link_info * info,asection * datasec,asection * relsec,char ** errmsg)436 bfd_m68k_coff_create_embedded_relocs (bfd *abfd,
437 struct bfd_link_info *info,
438 asection *datasec,
439 asection *relsec,
440 char **errmsg)
441 {
442 char *extsyms;
443 bfd_size_type symesz;
444 struct internal_reloc *irel, *irelend;
445 bfd_byte *p;
446 bfd_size_type amt;
447
448 BFD_ASSERT (! info->relocatable);
449
450 *errmsg = NULL;
451
452 if (datasec->reloc_count == 0)
453 return TRUE;
454
455 extsyms = obj_coff_external_syms (abfd);
456 symesz = bfd_coff_symesz (abfd);
457
458 irel = _bfd_coff_read_internal_relocs (abfd, datasec, TRUE, NULL, FALSE,
459 NULL);
460 irelend = irel + datasec->reloc_count;
461
462 amt = (bfd_size_type) datasec->reloc_count * 12;
463 relsec->contents = (bfd_byte *) bfd_alloc (abfd, amt);
464 if (relsec->contents == NULL)
465 return FALSE;
466
467 p = relsec->contents;
468
469 for (; irel < irelend; irel++, p += 12)
470 {
471 asection *targetsec;
472
473 /* We are going to write a four byte longword into the runtime
474 reloc section. The longword will be the address in the data
475 section which must be relocated. It is followed by the name
476 of the target section NUL-padded or truncated to 8
477 characters. */
478
479 /* We can only relocate absolute longword relocs at run time. */
480 if (irel->r_type != R_RELLONG)
481 {
482 *errmsg = _("unsupported reloc type");
483 bfd_set_error (bfd_error_bad_value);
484 return FALSE;
485 }
486
487 if (irel->r_symndx == -1)
488 targetsec = bfd_abs_section_ptr;
489 else
490 {
491 struct coff_link_hash_entry *h;
492
493 h = obj_coff_sym_hashes (abfd)[irel->r_symndx];
494 if (h == NULL)
495 {
496 struct internal_syment isym;
497
498 bfd_coff_swap_sym_in (abfd, extsyms + symesz * irel->r_symndx,
499 &isym);
500 targetsec = coff_section_from_bfd_index (abfd, isym.n_scnum);
501 }
502 else if (h->root.type == bfd_link_hash_defined
503 || h->root.type == bfd_link_hash_defweak)
504 targetsec = h->root.u.def.section;
505 else
506 targetsec = NULL;
507 }
508
509 bfd_put_32 (abfd,
510 (irel->r_vaddr - datasec->vma + datasec->output_offset), p);
511 memset (p + 4, 0, 8);
512 if (targetsec != NULL)
513 strncpy ((char *) p + 4, targetsec->output_section->name, 8);
514 }
515
516 return TRUE;
517 }
518 #endif /* neither ONLY_DECLARE_RELOCS not STATIC_RELOCS */
519
520 #define coff_bfd_is_local_label_name m68k_coff_is_local_label_name
521
522 #define coff_relocate_section _bfd_coff_generic_relocate_section
523
524 #ifndef bfd_pe_print_pdata
525 #define bfd_pe_print_pdata NULL
526 #endif
527
528 #include "coffcode.h"
529
530 #ifndef TARGET_SYM
531 #define TARGET_SYM m68k_coff_vec
532 #endif
533
534 #ifndef TARGET_NAME
535 #define TARGET_NAME "coff-m68k"
536 #endif
537
538 #ifdef NAMES_HAVE_UNDERSCORE
539 CREATE_BIG_COFF_TARGET_VEC (TARGET_SYM, TARGET_NAME, D_PAGED, 0, '_', NULL, COFF_SWAP_TABLE)
540 #else
541 CREATE_BIG_COFF_TARGET_VEC (TARGET_SYM, TARGET_NAME, D_PAGED, 0, 0, NULL, COFF_SWAP_TABLE)
542 #endif
543