source: trunk/src/binutils/bfd/coff-m68k.c@ 524

Last change on this file since 524 was 10, checked in by bird, 22 years ago

Initial revision
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1/* BFD back-end for Motorola 68000 COFF binaries.
2 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000
3 Free Software Foundation, Inc.
4 Written by Cygnus Support.
5
6This file is part of BFD, the Binary File Descriptor library.
7
8This program is free software; you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation; either version 2 of the License, or
11(at your option) any later version.
12
13This program is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along with this program; if not, write to the Free Software
20Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21
22#include "bfd.h"
23#include "sysdep.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 m68kcoff_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
60static bfd_reloc_status_type m68kcoff_common_addend_special_fn
61 PARAMS ((bfd *, arelent *, asymbol *, PTR, asection *, bfd *, char **));
62static reloc_howto_type *m68kcoff_common_addend_rtype_to_howto
63 PARAMS ((bfd *, asection *, struct internal_reloc *,
64 struct coff_link_hash_entry *, struct internal_syment *,
65 bfd_vma *));
66#define RELOC_SPECIAL_FN m68kcoff_common_addend_special_fn
67#endif
68
69static boolean m68k_coff_is_local_label_name PARAMS ((bfd *, const char *));
70
71/* On the delta, a symbol starting with L% is local. We won't see
72 such a symbol on other platforms, so it should be safe to always
73 consider it local here. */
74
75static boolean
76m68k_coff_is_local_label_name (abfd, name)
77 bfd *abfd;
78 const char *name;
79{
80 if (name[0] == 'L' && name[1] == '%')
81 return true;
82
83 return _bfd_coff_is_local_label_name (abfd, name);
84}
85
86#ifndef STATIC_RELOCS
87/* Clean up namespace. */
88#define m68kcoff_howto_table _bfd_m68kcoff_howto_table
89#define m68k_rtype2howto _bfd_m68kcoff_rtype2howto
90#define m68k_howto2rtype _bfd_m68kcoff_howto2rtype
91#define m68k_reloc_type_lookup _bfd_m68kcoff_reloc_type_lookup
92#endif
93
94#ifdef ONLY_DECLARE_RELOCS
95extern reloc_howto_type m68kcoff_howto_table[];
96#else
97#ifdef STATIC_RELOCS
98static
99#endif
100reloc_howto_type m68kcoff_howto_table[] =
101{
102 HOWTO(R_RELBYTE, 0, 0, 8, false, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "8", true, 0x000000ff,0x000000ff, false),
103 HOWTO(R_RELWORD, 0, 1, 16, false, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "16", true, 0x0000ffff,0x0000ffff, false),
104 HOWTO(R_RELLONG, 0, 2, 32, false, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "32", true, 0xffffffff,0xffffffff, false),
105 HOWTO(R_PCRBYTE, 0, 0, 8, true, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP8", true, 0x000000ff,0x000000ff, false),
106 HOWTO(R_PCRWORD, 0, 1, 16, true, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP16", true, 0x0000ffff,0x0000ffff, false),
107 HOWTO(R_PCRLONG, 0, 2, 32, true, 0, complain_overflow_signed, RELOC_SPECIAL_FN, "DISP32", true, 0xffffffff,0xffffffff, false),
108 HOWTO(R_RELLONG_NEG, 0, -2, 32, false, 0, complain_overflow_bitfield, RELOC_SPECIAL_FN, "-32", true, 0xffffffff,0xffffffff, false),
109};
110#endif /* not ONLY_DECLARE_RELOCS */
111
112#ifndef BADMAG
113#define BADMAG(x) M68KBADMAG(x)
114#endif
115#define M68 1 /* Customize coffcode.h */
116
117/* Turn a howto into a reloc number */
118
119#ifdef ONLY_DECLARE_RELOCS
120extern void m68k_rtype2howto PARAMS ((arelent *internal, int relocentry));
121extern int m68k_howto2rtype PARAMS ((reloc_howto_type *));
122extern reloc_howto_type *m68k_reloc_type_lookup
123 PARAMS ((bfd *, bfd_reloc_code_real_type));
124#else
125#ifdef STATIC_RELOCS
126static
127#endif
128void
129m68k_rtype2howto(internal, relocentry)
130 arelent *internal;
131 int relocentry;
132{
133 switch (relocentry)
134 {
135 case R_RELBYTE: internal->howto = m68kcoff_howto_table + 0; break;
136 case R_RELWORD: internal->howto = m68kcoff_howto_table + 1; break;
137 case R_RELLONG: internal->howto = m68kcoff_howto_table + 2; break;
138 case R_PCRBYTE: internal->howto = m68kcoff_howto_table + 3; break;
139 case R_PCRWORD: internal->howto = m68kcoff_howto_table + 4; break;
140 case R_PCRLONG: internal->howto = m68kcoff_howto_table + 5; break;
141 case R_RELLONG_NEG: internal->howto = m68kcoff_howto_table + 6; break;
142 }
143}
144
145#ifdef STATIC_RELOCS
146static
147#endif
148int
149m68k_howto2rtype (internal)
150 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#ifdef STATIC_RELOCS
174static
175#endif
176reloc_howto_type *
177m68k_reloc_type_lookup (abfd, code)
178 bfd *abfd ATTRIBUTE_UNUSED;
179 bfd_reloc_code_real_type code;
180{
181 switch (code)
182 {
183 default: return NULL;
184 case BFD_RELOC_8: return m68kcoff_howto_table + 0;
185 case BFD_RELOC_16: return m68kcoff_howto_table + 1;
186 case BFD_RELOC_CTOR:
187 case BFD_RELOC_32: return m68kcoff_howto_table + 2;
188 case BFD_RELOC_8_PCREL: return m68kcoff_howto_table + 3;
189 case BFD_RELOC_16_PCREL: return m68kcoff_howto_table + 4;
190 case BFD_RELOC_32_PCREL: return m68kcoff_howto_table + 5;
191 /* FIXME: There doesn't seem to be a code for R_RELLONG_NEG. */
192 }
193 /*NOTREACHED*/
194}
195
196#endif /* not ONLY_DECLARE_RELOCS */
197
198#define RTYPE2HOWTO(internal, relocentry) \
199 m68k_rtype2howto(internal, (relocentry)->r_type)
200
201#define SELECT_RELOC(external, internal) \
202 external.r_type = m68k_howto2rtype (internal)
203
204#define coff_bfd_reloc_type_lookup m68k_reloc_type_lookup
205
206#ifndef COFF_COMMON_ADDEND
207#ifndef coff_rtype_to_howto
208
209#define coff_rtype_to_howto m68kcoff_rtype_to_howto
210
211static reloc_howto_type *m68kcoff_rtype_to_howto
212 PARAMS ((bfd *, asection *, struct internal_reloc *,
213 struct coff_link_hash_entry *, struct internal_syment *,
214 bfd_vma *));
215
216static reloc_howto_type *
217m68kcoff_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
218 bfd *abfd ATTRIBUTE_UNUSED;
219 asection *sec;
220 struct internal_reloc *rel;
221 struct coff_link_hash_entry *h ATTRIBUTE_UNUSED;
222 struct internal_syment *sym ATTRIBUTE_UNUSED;
223 bfd_vma *addendp;
224{
225 arelent relent;
226 reloc_howto_type *howto;
227
228 RTYPE2HOWTO (&relent, rel);
229
230 howto = relent.howto;
231
232 if (howto->pc_relative)
233 *addendp += sec->vma;
234
235 return howto;
236}
237
238#endif /* ! defined (coff_rtype_to_howto) */
239#endif /* ! defined (COFF_COMMON_ADDEND) */
240
241
242#ifdef COFF_COMMON_ADDEND
243
244/* If COFF_COMMON_ADDEND is defined, then when using m68k COFF the
245 value stored in the .text section for a reference to a common
246 symbol is the value itself plus any desired offset. (taken from
247 work done by Ian Taylor, Cygnus Support, for I386 COFF). */
248
249/* If we are producing relocateable output, we need to do some
250 adjustments to the object file that are not done by the
251 bfd_perform_relocation function. This function is called by every
252 reloc type to make any required adjustments. */
253
254static bfd_reloc_status_type
255m68kcoff_common_addend_special_fn (abfd, reloc_entry, symbol, data,
256 input_section, output_bfd, error_message)
257 bfd *abfd;
258 arelent *reloc_entry;
259 asymbol *symbol;
260 PTR data;
261 asection *input_section ATTRIBUTE_UNUSED;
262 bfd *output_bfd;
263 char **error_message ATTRIBUTE_UNUSED;
264{
265 symvalue diff;
266
267 if (output_bfd == (bfd *) NULL)
268 return bfd_reloc_continue;
269
270 if (bfd_is_com_section (symbol->section))
271 {
272 /* We are relocating a common symbol. The current value in the
273 object file is ORIG + OFFSET, where ORIG is the value of the
274 common symbol as seen by the object file when it was compiled
275 (this may be zero if the symbol was undefined) and OFFSET is
276 the offset into the common symbol (normally zero, but may be
277 non-zero when referring to a field in a common structure).
278 ORIG is the negative of reloc_entry->addend, which is set by
279 the CALC_ADDEND macro below. We want to replace the value in
280 the object file with NEW + OFFSET, where NEW is the value of
281 the common symbol which we are going to put in the final
282 object file. NEW is symbol->value. */
283 diff = symbol->value + reloc_entry->addend;
284 }
285 else
286 {
287 /* For some reason bfd_perform_relocation always effectively
288 ignores the addend for a COFF target when producing
289 relocateable output. This seems to be always wrong for 386
290 COFF, so we handle the addend here instead. */
291 diff = reloc_entry->addend;
292 }
293
294#define DOIT(x) \
295 x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
296
297 if (diff != 0)
298 {
299 reloc_howto_type *howto = reloc_entry->howto;
300 unsigned char *addr = (unsigned char *) data + reloc_entry->address;
301
302 switch (howto->size)
303 {
304 case 0:
305 {
306 char x = bfd_get_8 (abfd, addr);
307 DOIT (x);
308 bfd_put_8 (abfd, x, addr);
309 }
310 break;
311
312 case 1:
313 {
314 short x = bfd_get_16 (abfd, addr);
315 DOIT (x);
316 bfd_put_16 (abfd, x, addr);
317 }
318 break;
319
320 case 2:
321 {
322 long x = bfd_get_32 (abfd, addr);
323 DOIT (x);
324 bfd_put_32 (abfd, x, addr);
325 }
326 break;
327
328 default:
329 abort ();
330 }
331 }
332
333 /* Now let bfd_perform_relocation finish everything up. */
334 return bfd_reloc_continue;
335}
336
337/* Compute the addend of a reloc. If the reloc is to a common symbol,
338 the object file contains the value of the common symbol. By the
339 time this is called, the linker may be using a different symbol
340 from a different object file with a different value. Therefore, we
341 hack wildly to locate the original symbol from this file so that we
342 can make the correct adjustment. This macro sets coffsym to the
343 symbol from the original file, and uses it to set the addend value
344 correctly. If this is not a common symbol, the usual addend
345 calculation is done, except that an additional tweak is needed for
346 PC relative relocs.
347 FIXME: This macro refers to symbols and asect; these are from the
348 calling function, not the macro arguments. */
349
350#define CALC_ADDEND(abfd, ptr, reloc, cache_ptr) \
351 { \
352 coff_symbol_type *coffsym = (coff_symbol_type *) NULL; \
353 if (ptr && bfd_asymbol_bfd (ptr) != abfd) \
354 coffsym = (obj_symbols (abfd) \
355 + (cache_ptr->sym_ptr_ptr - symbols)); \
356 else if (ptr) \
357 coffsym = coff_symbol_from (abfd, ptr); \
358 if (coffsym != (coff_symbol_type *) NULL \
359 && coffsym->native->u.syment.n_scnum == 0) \
360 cache_ptr->addend = - coffsym->native->u.syment.n_value; \
361 else if (ptr && bfd_asymbol_bfd (ptr) == abfd \
362 && ptr->section != (asection *) NULL) \
363 cache_ptr->addend = - (ptr->section->vma + ptr->value); \
364 else \
365 cache_ptr->addend = 0; \
366 if (ptr && (reloc.r_type == R_PCRBYTE \
367 || reloc.r_type == R_PCRWORD \
368 || reloc.r_type == R_PCRLONG)) \
369 cache_ptr->addend += asect->vma; \
370 }
371
372#ifndef coff_rtype_to_howto
373
374/* coff-m68k.c uses the special COFF backend linker. We need to
375 adjust common symbols. */
376
377static reloc_howto_type *
378m68kcoff_common_addend_rtype_to_howto (abfd, sec, rel, h, sym, addendp)
379 bfd *abfd ATTRIBUTE_UNUSED;
380 asection *sec;
381 struct internal_reloc *rel;
382 struct coff_link_hash_entry *h;
383 struct internal_syment *sym;
384 bfd_vma *addendp;
385{
386 arelent relent;
387 reloc_howto_type *howto;
388
389 RTYPE2HOWTO (&relent, rel);
390
391 howto = relent.howto;
392
393 if (howto->pc_relative)
394 *addendp += sec->vma;
395
396 if (sym != NULL && sym->n_scnum == 0 && sym->n_value != 0)
397 {
398 /* This is a common symbol. The section contents include the
399 size (sym->n_value) as an addend. The relocate_section
400 function will be adding in the final value of the symbol. We
401 need to subtract out the current size in order to get the
402 correct result. */
403 BFD_ASSERT (h != NULL);
404 *addendp -= sym->n_value;
405 }
406
407 /* If the output symbol is common (in which case this must be a
408 relocateable link), we need to add in the final size of the
409 common symbol. */
410 if (h != NULL && h->root.type == bfd_link_hash_common)
411 *addendp += h->root.u.c.size;
412
413 return howto;
414}
415
416#define coff_rtype_to_howto m68kcoff_common_addend_rtype_to_howto
417
418#endif /* ! defined (coff_rtype_to_howto) */
419
420#endif /* COFF_COMMON_ADDEND */
421
422#if !defined ONLY_DECLARE_RELOCS && ! defined STATIC_RELOCS
423/* Given a .data section and a .emreloc in-memory section, store
424 relocation information into the .emreloc section which can be
425 used at runtime to relocate the section. This is called by the
426 linker when the --embedded-relocs switch is used. This is called
427 after the add_symbols entry point has been called for all the
428 objects, and before the final_link entry point is called. */
429
430boolean
431bfd_m68k_coff_create_embedded_relocs (abfd, info, datasec, relsec, errmsg)
432 bfd *abfd;
433 struct bfd_link_info *info;
434 asection *datasec;
435 asection *relsec;
436 char **errmsg;
437{
438 char *extsyms;
439 bfd_size_type symesz;
440 struct internal_reloc *irel, *irelend;
441 bfd_byte *p;
442
443 BFD_ASSERT (! info->relocateable);
444
445 *errmsg = NULL;
446
447 if (datasec->reloc_count == 0)
448 return true;
449
450 extsyms = obj_coff_external_syms (abfd);
451 symesz = bfd_coff_symesz (abfd);
452
453 irel = _bfd_coff_read_internal_relocs (abfd, datasec, true, NULL, false,
454 NULL);
455 irelend = irel + datasec->reloc_count;
456
457 relsec->contents = (bfd_byte *) bfd_alloc (abfd, datasec->reloc_count * 12);
458 if (relsec->contents == NULL)
459 return false;
460
461 p = relsec->contents;
462
463 for (; irel < irelend; irel++, p += 12)
464 {
465 asection *targetsec;
466
467 /* We are going to write a four byte longword into the runtime
468 reloc section. The longword will be the address in the data
469 section which must be relocated. It is followed by the name
470 of the target section NUL-padded or truncated to 8
471 characters. */
472
473 /* We can only relocate absolute longword relocs at run time. */
474 if (irel->r_type != R_RELLONG)
475 {
476 *errmsg = _("unsupported reloc type");
477 bfd_set_error (bfd_error_bad_value);
478 return false;
479 }
480
481 if (irel->r_symndx == -1)
482 targetsec = bfd_abs_section_ptr;
483 else
484 {
485 struct coff_link_hash_entry *h;
486
487 h = obj_coff_sym_hashes (abfd)[irel->r_symndx];
488 if (h == NULL)
489 {
490 struct internal_syment isym;
491
492 bfd_coff_swap_sym_in (abfd, extsyms + symesz * irel->r_symndx,
493 &isym);
494 targetsec = coff_section_from_bfd_index (abfd, isym.n_scnum);
495 }
496 else if (h->root.type == bfd_link_hash_defined
497 || h->root.type == bfd_link_hash_defweak)
498 targetsec = h->root.u.def.section;
499 else
500 targetsec = NULL;
501 }
502
503 bfd_put_32 (abfd,
504 (irel->r_vaddr - datasec->vma + datasec->output_offset), p);
505 memset (p + 4, 0, 8);
506 if (targetsec != NULL)
507 strncpy (p + 4, targetsec->output_section->name, 8);
508 }
509
510 return true;
511}
512#endif /* neither ONLY_DECLARE_RELOCS not STATIC_RELOCS */
513
514
515#define coff_bfd_is_local_label_name m68k_coff_is_local_label_name
516
517#define coff_relocate_section _bfd_coff_generic_relocate_section
518
519#include "coffcode.h"
520
521#ifndef TARGET_SYM
522#define TARGET_SYM m68kcoff_vec
523#endif
524
525#ifndef TARGET_NAME
526#define TARGET_NAME "coff-m68k"
527#endif
528
529#ifdef NAMES_HAVE_UNDERSCORE
530CREATE_BIG_COFF_TARGET_VEC (TARGET_SYM, TARGET_NAME, D_PAGED, 0, '_', NULL)
531#else
532CREATE_BIG_COFF_TARGET_VEC (TARGET_SYM, TARGET_NAME, D_PAGED, 0, 0, NULL)
533#endif
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