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1 /* BFD support for handling relocation entries.
2 Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 1997, 1998
3 Free Software Foundation, Inc.
4 Written by Cygnus Support.
5
6 This file is part of BFD, the Binary File Descriptor library.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21
22 /*
23 SECTION
24 Relocations
25
26 BFD maintains relocations in much the same way it maintains
27 symbols: they are left alone until required, then read in
28 en-mass and translated into an internal form. A common
29 routine <<bfd_perform_relocation>> acts upon the
30 canonical form to do the fixup.
31
32 Relocations are maintained on a per section basis,
33 while symbols are maintained on a per BFD basis.
34
35 All that a back end has to do to fit the BFD interface is to create
36 a <<struct reloc_cache_entry>> for each relocation
37 in a particular section, and fill in the right bits of the structures.
38
39 @menu
40 @* typedef arelent::
41 @* howto manager::
42 @end menu
43
44 */
45
46 /* DO compile in the reloc_code name table from libbfd.h. */
47 #define _BFD_MAKE_TABLE_bfd_reloc_code_real
48
49 #include "bfd.h"
50 #include "sysdep.h"
51 #include "bfdlink.h"
52 #include "libbfd.h"
53 /*
54 DOCDD
55 INODE
56 typedef arelent, howto manager, Relocations, Relocations
57
58 SUBSECTION
59 typedef arelent
60
61 This is the structure of a relocation entry:
62
63 CODE_FRAGMENT
64 .
65 .typedef enum bfd_reloc_status
66 .{
67 . {* No errors detected *}
68 . bfd_reloc_ok,
69 .
70 . {* The relocation was performed, but there was an overflow. *}
71 . bfd_reloc_overflow,
72 .
73 . {* The address to relocate was not within the section supplied. *}
74 . bfd_reloc_outofrange,
75 .
76 . {* Used by special functions *}
77 . bfd_reloc_continue,
78 .
79 . {* Unsupported relocation size requested. *}
80 . bfd_reloc_notsupported,
81 .
82 . {* Unused *}
83 . bfd_reloc_other,
84 .
85 . {* The symbol to relocate against was undefined. *}
86 . bfd_reloc_undefined,
87 .
88 . {* The relocation was performed, but may not be ok - presently
89 . generated only when linking i960 coff files with i960 b.out
90 . symbols. If this type is returned, the error_message argument
91 . to bfd_perform_relocation will be set. *}
92 . bfd_reloc_dangerous
93 . }
94 . bfd_reloc_status_type;
95 .
96 .
97 .typedef struct reloc_cache_entry
98 .{
99 . {* A pointer into the canonical table of pointers *}
100 . struct symbol_cache_entry **sym_ptr_ptr;
101 .
102 . {* offset in section *}
103 . bfd_size_type address;
104 .
105 . {* addend for relocation value *}
106 . bfd_vma addend;
107 .
108 . {* Pointer to how to perform the required relocation *}
109 . reloc_howto_type *howto;
110 .
111 .} arelent;
112
113 */
114
115 /*
116 DESCRIPTION
117
118 Here is a description of each of the fields within an <<arelent>>:
119
120 o <<sym_ptr_ptr>>
121
122 The symbol table pointer points to a pointer to the symbol
123 associated with the relocation request. It is
124 the pointer into the table returned by the back end's
125 <<get_symtab>> action. @xref{Symbols}. The symbol is referenced
126 through a pointer to a pointer so that tools like the linker
127 can fix up all the symbols of the same name by modifying only
128 one pointer. The relocation routine looks in the symbol and
129 uses the base of the section the symbol is attached to and the
130 value of the symbol as the initial relocation offset. If the
131 symbol pointer is zero, then the section provided is looked up.
132
133 o <<address>>
134
135 The <<address>> field gives the offset in bytes from the base of
136 the section data which owns the relocation record to the first
137 byte of relocatable information. The actual data relocated
138 will be relative to this point; for example, a relocation
139 type which modifies the bottom two bytes of a four byte word
140 would not touch the first byte pointed to in a big endian
141 world.
142
143 o <<addend>>
144
145 The <<addend>> is a value provided by the back end to be added (!)
146 to the relocation offset. Its interpretation is dependent upon
147 the howto. For example, on the 68k the code:
148
149
150 | char foo[];
151 | main()
152 | {
153 | return foo[0x12345678];
154 | }
155
156 Could be compiled into:
157
158 | linkw fp,#-4
159 | moveb @@#12345678,d0
160 | extbl d0
161 | unlk fp
162 | rts
163
164
165 This could create a reloc pointing to <<foo>>, but leave the
166 offset in the data, something like:
167
168
169 |RELOCATION RECORDS FOR [.text]:
170 |offset type value
171 |00000006 32 _foo
172 |
173 |00000000 4e56 fffc ; linkw fp,#-4
174 |00000004 1039 1234 5678 ; moveb @@#12345678,d0
175 |0000000a 49c0 ; extbl d0
176 |0000000c 4e5e ; unlk fp
177 |0000000e 4e75 ; rts
178
179
180 Using coff and an 88k, some instructions don't have enough
181 space in them to represent the full address range, and
182 pointers have to be loaded in two parts. So you'd get something like:
183
184
185 | or.u r13,r0,hi16(_foo+0x12345678)
186 | ld.b r2,r13,lo16(_foo+0x12345678)
187 | jmp r1
188
189
190 This should create two relocs, both pointing to <<_foo>>, and with
191 0x12340000 in their addend field. The data would consist of:
192
193
194 |RELOCATION RECORDS FOR [.text]:
195 |offset type value
196 |00000002 HVRT16 _foo+0x12340000
197 |00000006 LVRT16 _foo+0x12340000
198 |
199 |00000000 5da05678 ; or.u r13,r0,0x5678
200 |00000004 1c4d5678 ; ld.b r2,r13,0x5678
201 |00000008 f400c001 ; jmp r1
202
203
204 The relocation routine digs out the value from the data, adds
205 it to the addend to get the original offset, and then adds the
206 value of <<_foo>>. Note that all 32 bits have to be kept around
207 somewhere, to cope with carry from bit 15 to bit 16.
208
209 One further example is the sparc and the a.out format. The
210 sparc has a similar problem to the 88k, in that some
211 instructions don't have room for an entire offset, but on the
212 sparc the parts are created in odd sized lumps. The designers of
213 the a.out format chose to not use the data within the section
214 for storing part of the offset; all the offset is kept within
215 the reloc. Anything in the data should be ignored.
216
217 | save %sp,-112,%sp
218 | sethi %hi(_foo+0x12345678),%g2
219 | ldsb [%g2+%lo(_foo+0x12345678)],%i0
220 | ret
221 | restore
222
223 Both relocs contain a pointer to <<foo>>, and the offsets
224 contain junk.
225
226
227 |RELOCATION RECORDS FOR [.text]:
228 |offset type value
229 |00000004 HI22 _foo+0x12345678
230 |00000008 LO10 _foo+0x12345678
231 |
232 |00000000 9de3bf90 ; save %sp,-112,%sp
233 |00000004 05000000 ; sethi %hi(_foo+0),%g2
234 |00000008 f048a000 ; ldsb [%g2+%lo(_foo+0)],%i0
235 |0000000c 81c7e008 ; ret
236 |00000010 81e80000 ; restore
237
238
239 o <<howto>>
240
241 The <<howto>> field can be imagined as a
242 relocation instruction. It is a pointer to a structure which
243 contains information on what to do with all of the other
244 information in the reloc record and data section. A back end
245 would normally have a relocation instruction set and turn
246 relocations into pointers to the correct structure on input -
247 but it would be possible to create each howto field on demand.
248
249 */
250
251 /*
252 SUBSUBSECTION
253 <<enum complain_overflow>>
254
255 Indicates what sort of overflow checking should be done when
256 performing a relocation.
257
258 CODE_FRAGMENT
259 .
260 .enum complain_overflow
261 .{
262 . {* Do not complain on overflow. *}
263 . complain_overflow_dont,
264 .
265 . {* Complain if the bitfield overflows, whether it is considered
266 . as signed or unsigned. *}
267 . complain_overflow_bitfield,
268 .
269 . {* Complain if the value overflows when considered as signed
270 . number. *}
271 . complain_overflow_signed,
272 .
273 . {* Complain if the value overflows when considered as an
274 . unsigned number. *}
275 . complain_overflow_unsigned
276 .};
277
278 */
279
280 /*
281 SUBSUBSECTION
282 <<reloc_howto_type>>
283
284 The <<reloc_howto_type>> is a structure which contains all the
285 information that libbfd needs to know to tie up a back end's data.
286
287 CODE_FRAGMENT
288 .struct symbol_cache_entry; {* Forward declaration *}
289 .
290 .struct reloc_howto_struct
291 .{
292 . {* The type field has mainly a documentary use - the back end can
293 . do what it wants with it, though normally the back end's
294 . external idea of what a reloc number is stored
295 . in this field. For example, a PC relative word relocation
296 . in a coff environment has the type 023 - because that's
297 . what the outside world calls a R_PCRWORD reloc. *}
298 . unsigned int type;
299 .
300 . {* The value the final relocation is shifted right by. This drops
301 . unwanted data from the relocation. *}
302 . unsigned int rightshift;
303 .
304 . {* The size of the item to be relocated. This is *not* a
305 . power-of-two measure. To get the number of bytes operated
306 . on by a type of relocation, use bfd_get_reloc_size. *}
307 . int size;
308 .
309 . {* The number of bits in the item to be relocated. This is used
310 . when doing overflow checking. *}
311 . unsigned int bitsize;
312 .
313 . {* Notes that the relocation is relative to the location in the
314 . data section of the addend. The relocation function will
315 . subtract from the relocation value the address of the location
316 . being relocated. *}
317 . boolean pc_relative;
318 .
319 . {* The bit position of the reloc value in the destination.
320 . The relocated value is left shifted by this amount. *}
321 . unsigned int bitpos;
322 .
323 . {* What type of overflow error should be checked for when
324 . relocating. *}
325 . enum complain_overflow complain_on_overflow;
326 .
327 . {* If this field is non null, then the supplied function is
328 . called rather than the normal function. This allows really
329 . strange relocation methods to be accomodated (e.g., i960 callj
330 . instructions). *}
331 . bfd_reloc_status_type (*special_function)
332 . PARAMS ((bfd *abfd,
333 . arelent *reloc_entry,
334 . struct symbol_cache_entry *symbol,
335 . PTR data,
336 . asection *input_section,
337 . bfd *output_bfd,
338 . char **error_message));
339 .
340 . {* The textual name of the relocation type. *}
341 . char *name;
342 .
343 . {* When performing a partial link, some formats must modify the
344 . relocations rather than the data - this flag signals this.*}
345 . boolean partial_inplace;
346 .
347 . {* The src_mask selects which parts of the read in data
348 . are to be used in the relocation sum. E.g., if this was an 8 bit
349 . bit of data which we read and relocated, this would be
350 . 0x000000ff. When we have relocs which have an addend, such as
351 . sun4 extended relocs, the value in the offset part of a
352 . relocating field is garbage so we never use it. In this case
353 . the mask would be 0x00000000. *}
354 . bfd_vma src_mask;
355 .
356 . {* The dst_mask selects which parts of the instruction are replaced
357 . into the instruction. In most cases src_mask == dst_mask,
358 . except in the above special case, where dst_mask would be
359 . 0x000000ff, and src_mask would be 0x00000000. *}
360 . bfd_vma dst_mask;
361 .
362 . {* When some formats create PC relative instructions, they leave
363 . the value of the pc of the place being relocated in the offset
364 . slot of the instruction, so that a PC relative relocation can
365 . be made just by adding in an ordinary offset (e.g., sun3 a.out).
366 . Some formats leave the displacement part of an instruction
367 . empty (e.g., m88k bcs); this flag signals the fact.*}
368 . boolean pcrel_offset;
369 .
370 .};
371
372 */
373
374 /*
375 FUNCTION
376 The HOWTO Macro
377
378 DESCRIPTION
379 The HOWTO define is horrible and will go away.
380
381
382 .#define HOWTO(C, R,S,B, P, BI, O, SF, NAME, INPLACE, MASKSRC, MASKDST, PC) \
383 . {(unsigned)C,R,S,B, P, BI, O,SF,NAME,INPLACE,MASKSRC,MASKDST,PC}
384
385 DESCRIPTION
386 And will be replaced with the totally magic way. But for the
387 moment, we are compatible, so do it this way.
388
389
390 .#define NEWHOWTO( FUNCTION, NAME,SIZE,REL,IN) HOWTO(0,0,SIZE,0,REL,0,complain_overflow_dont,FUNCTION, NAME,false,0,0,IN)
391 .
392 DESCRIPTION
393 Helper routine to turn a symbol into a relocation value.
394
395 .#define HOWTO_PREPARE(relocation, symbol) \
396 . { \
397 . if (symbol != (asymbol *)NULL) { \
398 . if (bfd_is_com_section (symbol->section)) { \
399 . relocation = 0; \
400 . } \
401 . else { \
402 . relocation = symbol->value; \
403 . } \
404 . } \
405 .}
406
407 */
408
409 /*
410 FUNCTION
411 bfd_get_reloc_size
412
413 SYNOPSIS
414 int bfd_get_reloc_size (reloc_howto_type *);
415
416 DESCRIPTION
417 For a reloc_howto_type that operates on a fixed number of bytes,
418 this returns the number of bytes operated on.
419 */
420
421 int
422 bfd_get_reloc_size (howto)
423 reloc_howto_type *howto;
424 {
425 switch (howto->size)
426 {
427 case 0: return 1;
428 case 1: return 2;
429 case 2: return 4;
430 case 3: return 0;
431 case 4: return 8;
432 case 8: return 16;
433 case -2: return 4;
434 default: abort ();
435 }
436 }
437
438 /*
439 TYPEDEF
440 arelent_chain
441
442 DESCRIPTION
443
444 How relocs are tied together in an <<asection>>:
445
446 .typedef struct relent_chain {
447 . arelent relent;
448 . struct relent_chain *next;
449 .} arelent_chain;
450
451 */
452
453
454 /*
455 FUNCTION
456 bfd_check_overflow
457
458 SYNOPSIS
459 bfd_reloc_status_type
460 bfd_check_overflow
461 (enum complain_overflow how,
462 unsigned int bitsize,
463 unsigned int rightshift,
464 bfd_vma relocation);
465
466 DESCRIPTION
467 Perform overflow checking on @var{relocation} which has @var{bitsize}
468 significant bits and will be shifted right by @var{rightshift} bits.
469 The result is either of @code{bfd_reloc_ok} or
470 @code{bfd_reloc_overflow}.
471
472 */
473
474 bfd_reloc_status_type
475 bfd_check_overflow (how, bitsize, rightshift, relocation)
476 enum complain_overflow how;
477 unsigned int bitsize, rightshift;
478 bfd_vma relocation;
479 {
480 bfd_vma check;
481 bfd_reloc_status_type flag = bfd_reloc_ok;
482
483 /* Get the value that will be used for the relocation, but
484 starting at bit position zero. */
485 check = relocation >> rightshift;
486
487 switch (how)
488 {
489 case complain_overflow_dont:
490 break;
491
492 case complain_overflow_signed:
493 {
494 /* Assumes two's complement. */
495 bfd_signed_vma reloc_signed_max = (1 << (bitsize - 1)) - 1;
496 bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
497
498 /* The above right shift is incorrect for a signed value.
499 Fix it up by forcing on the upper bits. */
500 if (rightshift > 0
501 && (bfd_signed_vma) relocation < 0)
502 check |= ((bfd_vma) - 1
503 & ~((bfd_vma) - 1
504 >> rightshift));
505 if ((bfd_signed_vma) check > reloc_signed_max
506 || (bfd_signed_vma) check < reloc_signed_min)
507 flag = bfd_reloc_overflow;
508 }
509 break;
510
511 case complain_overflow_unsigned:
512 {
513 /* Assumes two's complement. This expression avoids
514 overflow if `bitsize' is the number of bits in
515 bfd_vma. */
516 bfd_vma reloc_unsigned_max = (((1 << (bitsize - 1)) - 1) << 1) | 1;
517
518 if ((bfd_vma) check > reloc_unsigned_max)
519 flag = bfd_reloc_overflow;
520 }
521 break;
522
523 case complain_overflow_bitfield:
524 {
525 /* Assumes two's complement. This expression avoids
526 overflow if `bitsize' is the number of bits in
527 bfd_vma. */
528 bfd_vma reloc_bits = (((1 << (bitsize - 1)) - 1) << 1) | 1;
529
530 if (((bfd_vma) check & ~reloc_bits) != 0
531 && ((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
532 {
533 /* The above right shift is incorrect for a signed
534 value. See if turning on the upper bits fixes the
535 overflow. */
536 if (rightshift > 0
537 && (bfd_signed_vma) relocation < 0)
538 {
539 check |= ((bfd_vma) - 1
540 & ~((bfd_vma) - 1
541 >> rightshift));
542 if (((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
543 flag = bfd_reloc_overflow;
544 }
545 else
546 flag = bfd_reloc_overflow;
547 }
548 }
549 break;
550
551 default:
552 abort ();
553 }
554
555 return flag;
556 }
557
558
559 /*
560 FUNCTION
561 bfd_perform_relocation
562
563 SYNOPSIS
564 bfd_reloc_status_type
565 bfd_perform_relocation
566 (bfd *abfd,
567 arelent *reloc_entry,
568 PTR data,
569 asection *input_section,
570 bfd *output_bfd,
571 char **error_message);
572
573 DESCRIPTION
574 If @var{output_bfd} is supplied to this function, the
575 generated image will be relocatable; the relocations are
576 copied to the output file after they have been changed to
577 reflect the new state of the world. There are two ways of
578 reflecting the results of partial linkage in an output file:
579 by modifying the output data in place, and by modifying the
580 relocation record. Some native formats (e.g., basic a.out and
581 basic coff) have no way of specifying an addend in the
582 relocation type, so the addend has to go in the output data.
583 This is no big deal since in these formats the output data
584 slot will always be big enough for the addend. Complex reloc
585 types with addends were invented to solve just this problem.
586 The @var{error_message} argument is set to an error message if
587 this return @code{bfd_reloc_dangerous}.
588
589 */
590
591
592 bfd_reloc_status_type
593 bfd_perform_relocation (abfd, reloc_entry, data, input_section, output_bfd,
594 error_message)
595 bfd *abfd;
596 arelent *reloc_entry;
597 PTR data;
598 asection *input_section;
599 bfd *output_bfd;
600 char **error_message;
601 {
602 bfd_vma relocation;
603 bfd_reloc_status_type flag = bfd_reloc_ok;
604 bfd_size_type addr = reloc_entry->address;
605 bfd_vma output_base = 0;
606 reloc_howto_type *howto = reloc_entry->howto;
607 asection *reloc_target_output_section;
608 asymbol *symbol;
609
610 symbol = *(reloc_entry->sym_ptr_ptr);
611 if (bfd_is_abs_section (symbol->section)
612 && output_bfd != (bfd *) NULL)
613 {
614 reloc_entry->address += input_section->output_offset;
615 return bfd_reloc_ok;
616 }
617
618 /* If we are not producing relocateable output, return an error if
619 the symbol is not defined. An undefined weak symbol is
620 considered to have a value of zero (SVR4 ABI, p. 4-27). */
621 if (bfd_is_und_section (symbol->section)
622 && (symbol->flags & BSF_WEAK) == 0
623 && output_bfd == (bfd *) NULL)
624 flag = bfd_reloc_undefined;
625
626 /* If there is a function supplied to handle this relocation type,
627 call it. It'll return `bfd_reloc_continue' if further processing
628 can be done. */
629 if (howto->special_function)
630 {
631 bfd_reloc_status_type cont;
632 cont = howto->special_function (abfd, reloc_entry, symbol, data,
633 input_section, output_bfd,
634 error_message);
635 if (cont != bfd_reloc_continue)
636 return cont;
637 }
638
639 /* Is the address of the relocation really within the section? */
640 if (reloc_entry->address > input_section->_cooked_size)
641 return bfd_reloc_outofrange;
642
643 /* Work out which section the relocation is targetted at and the
644 initial relocation command value. */
645
646 /* Get symbol value. (Common symbols are special.) */
647 if (bfd_is_com_section (symbol->section))
648 relocation = 0;
649 else
650 relocation = symbol->value;
651
652
653 reloc_target_output_section = symbol->section->output_section;
654
655 /* Convert input-section-relative symbol value to absolute. */
656 if (output_bfd && howto->partial_inplace == false)
657 output_base = 0;
658 else
659 output_base = reloc_target_output_section->vma;
660
661 relocation += output_base + symbol->section->output_offset;
662
663 /* Add in supplied addend. */
664 relocation += reloc_entry->addend;
665
666 /* Here the variable relocation holds the final address of the
667 symbol we are relocating against, plus any addend. */
668
669 if (howto->pc_relative == true)
670 {
671 /* This is a PC relative relocation. We want to set RELOCATION
672 to the distance between the address of the symbol and the
673 location. RELOCATION is already the address of the symbol.
674
675 We start by subtracting the address of the section containing
676 the location.
677
678 If pcrel_offset is set, we must further subtract the position
679 of the location within the section. Some targets arrange for
680 the addend to be the negative of the position of the location
681 within the section; for example, i386-aout does this. For
682 i386-aout, pcrel_offset is false. Some other targets do not
683 include the position of the location; for example, m88kbcs,
684 or ELF. For those targets, pcrel_offset is true.
685
686 If we are producing relocateable output, then we must ensure
687 that this reloc will be correctly computed when the final
688 relocation is done. If pcrel_offset is false we want to wind
689 up with the negative of the location within the section,
690 which means we must adjust the existing addend by the change
691 in the location within the section. If pcrel_offset is true
692 we do not want to adjust the existing addend at all.
693
694 FIXME: This seems logical to me, but for the case of
695 producing relocateable output it is not what the code
696 actually does. I don't want to change it, because it seems
697 far too likely that something will break. */
698
699 relocation -=
700 input_section->output_section->vma + input_section->output_offset;
701
702 if (howto->pcrel_offset == true)
703 relocation -= reloc_entry->address;
704 }
705
706 if (output_bfd != (bfd *) NULL)
707 {
708 if (howto->partial_inplace == false)
709 {
710 /* This is a partial relocation, and we want to apply the relocation
711 to the reloc entry rather than the raw data. Modify the reloc
712 inplace to reflect what we now know. */
713 reloc_entry->addend = relocation;
714 reloc_entry->address += input_section->output_offset;
715 return flag;
716 }
717 else
718 {
719 /* This is a partial relocation, but inplace, so modify the
720 reloc record a bit.
721
722 If we've relocated with a symbol with a section, change
723 into a ref to the section belonging to the symbol. */
724
725 reloc_entry->address += input_section->output_offset;
726
727 /* WTF?? */
728 if (abfd->xvec->flavour == bfd_target_coff_flavour
729 && strcmp (abfd->xvec->name, "aixcoff-rs6000") != 0
730 && strcmp (abfd->xvec->name, "xcoff-powermac") != 0
731 && strcmp (abfd->xvec->name, "coff-Intel-little") != 0
732 && strcmp (abfd->xvec->name, "coff-Intel-big") != 0)
733 {
734 #if 1
735 /* For m68k-coff, the addend was being subtracted twice during
736 relocation with -r. Removing the line below this comment
737 fixes that problem; see PR 2953.
738
739 However, Ian wrote the following, regarding removing the line below,
740 which explains why it is still enabled: --djm
741
742 If you put a patch like that into BFD you need to check all the COFF
743 linkers. I am fairly certain that patch will break coff-i386 (e.g.,
744 SCO); see coff_i386_reloc in coff-i386.c where I worked around the
745 problem in a different way. There may very well be a reason that the
746 code works as it does.
747
748 Hmmm. The first obvious point is that bfd_perform_relocation should
749 not have any tests that depend upon the flavour. It's seem like
750 entirely the wrong place for such a thing. The second obvious point
751 is that the current code ignores the reloc addend when producing
752 relocateable output for COFF. That's peculiar. In fact, I really
753 have no idea what the point of the line you want to remove is.
754
755 A typical COFF reloc subtracts the old value of the symbol and adds in
756 the new value to the location in the object file (if it's a pc
757 relative reloc it adds the difference between the symbol value and the
758 location). When relocating we need to preserve that property.
759
760 BFD handles this by setting the addend to the negative of the old
761 value of the symbol. Unfortunately it handles common symbols in a
762 non-standard way (it doesn't subtract the old value) but that's a
763 different story (we can't change it without losing backward
764 compatibility with old object files) (coff-i386 does subtract the old
765 value, to be compatible with existing coff-i386 targets, like SCO).
766
767 So everything works fine when not producing relocateable output. When
768 we are producing relocateable output, logically we should do exactly
769 what we do when not producing relocateable output. Therefore, your
770 patch is correct. In fact, it should probably always just set
771 reloc_entry->addend to 0 for all cases, since it is, in fact, going to
772 add the value into the object file. This won't hurt the COFF code,
773 which doesn't use the addend; I'm not sure what it will do to other
774 formats (the thing to check for would be whether any formats both use
775 the addend and set partial_inplace).
776
777 When I wanted to make coff-i386 produce relocateable output, I ran
778 into the problem that you are running into: I wanted to remove that
779 line. Rather than risk it, I made the coff-i386 relocs use a special
780 function; it's coff_i386_reloc in coff-i386.c. The function
781 specifically adds the addend field into the object file, knowing that
782 bfd_perform_relocation is not going to. If you remove that line, then
783 coff-i386.c will wind up adding the addend field in twice. It's
784 trivial to fix; it just needs to be done.
785
786 The problem with removing the line is just that it may break some
787 working code. With BFD it's hard to be sure of anything. The right
788 way to deal with this is simply to build and test at least all the
789 supported COFF targets. It should be straightforward if time and disk
790 space consuming. For each target:
791 1) build the linker
792 2) generate some executable, and link it using -r (I would
793 probably use paranoia.o and link against newlib/libc.a, which
794 for all the supported targets would be available in
795 /usr/cygnus/progressive/H-host/target/lib/libc.a).
796 3) make the change to reloc.c
797 4) rebuild the linker
798 5) repeat step 2
799 6) if the resulting object files are the same, you have at least
800 made it no worse
801 7) if they are different you have to figure out which version is
802 right
803 */
804 relocation -= reloc_entry->addend;
805 #endif
806 reloc_entry->addend = 0;
807 }
808 else
809 {
810 reloc_entry->addend = relocation;
811 }
812 }
813 }
814 else
815 {
816 reloc_entry->addend = 0;
817 }
818
819 /* FIXME: This overflow checking is incomplete, because the value
820 might have overflowed before we get here. For a correct check we
821 need to compute the value in a size larger than bitsize, but we
822 can't reasonably do that for a reloc the same size as a host
823 machine word.
824 FIXME: We should also do overflow checking on the result after
825 adding in the value contained in the object file. */
826 if (howto->complain_on_overflow != complain_overflow_dont
827 && flag == bfd_reloc_ok)
828 flag = bfd_check_overflow (howto->complain_on_overflow, howto->bitsize,
829 howto->rightshift, relocation);
830
831 /*
832 Either we are relocating all the way, or we don't want to apply
833 the relocation to the reloc entry (probably because there isn't
834 any room in the output format to describe addends to relocs)
835 */
836
837 /* The cast to bfd_vma avoids a bug in the Alpha OSF/1 C compiler
838 (OSF version 1.3, compiler version 3.11). It miscompiles the
839 following program:
840
841 struct str
842 {
843 unsigned int i0;
844 } s = { 0 };
845
846 int
847 main ()
848 {
849 unsigned long x;
850
851 x = 0x100000000;
852 x <<= (unsigned long) s.i0;
853 if (x == 0)
854 printf ("failed\n");
855 else
856 printf ("succeeded (%lx)\n", x);
857 }
858 */
859
860 relocation >>= (bfd_vma) howto->rightshift;
861
862 /* Shift everything up to where it's going to be used */
863
864 relocation <<= (bfd_vma) howto->bitpos;
865
866 /* Wait for the day when all have the mask in them */
867
868 /* What we do:
869 i instruction to be left alone
870 o offset within instruction
871 r relocation offset to apply
872 S src mask
873 D dst mask
874 N ~dst mask
875 A part 1
876 B part 2
877 R result
878
879 Do this:
880 i i i i i o o o o o from bfd_get<size>
881 and S S S S S to get the size offset we want
882 + r r r r r r r r r r to get the final value to place
883 and D D D D D to chop to right size
884 -----------------------
885 A A A A A
886 And this:
887 ... i i i i i o o o o o from bfd_get<size>
888 and N N N N N get instruction
889 -----------------------
890 ... B B B B B
891
892 And then:
893 B B B B B
894 or A A A A A
895 -----------------------
896 R R R R R R R R R R put into bfd_put<size>
897 */
898
899 #define DOIT(x) \
900 x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) + relocation) & howto->dst_mask))
901
902 switch (howto->size)
903 {
904 case 0:
905 {
906 char x = bfd_get_8 (abfd, (char *) data + addr);
907 DOIT (x);
908 bfd_put_8 (abfd, x, (unsigned char *) data + addr);
909 }
910 break;
911
912 case 1:
913 {
914 short x = bfd_get_16 (abfd, (bfd_byte *) data + addr);
915 DOIT (x);
916 bfd_put_16 (abfd, x, (unsigned char *) data + addr);
917 }
918 break;
919 case 2:
920 {
921 long x = bfd_get_32 (abfd, (bfd_byte *) data + addr);
922 DOIT (x);
923 bfd_put_32 (abfd, x, (bfd_byte *) data + addr);
924 }
925 break;
926 case -2:
927 {
928 long x = bfd_get_32 (abfd, (bfd_byte *) data + addr);
929 relocation = -relocation;
930 DOIT (x);
931 bfd_put_32 (abfd, x, (bfd_byte *) data + addr);
932 }
933 break;
934
935 case -1:
936 {
937 long x = bfd_get_16 (abfd, (bfd_byte *) data + addr);
938 relocation = -relocation;
939 DOIT (x);
940 bfd_put_16 (abfd, x, (bfd_byte *) data + addr);
941 }
942 break;
943
944 case 3:
945 /* Do nothing */
946 break;
947
948 case 4:
949 #ifdef BFD64
950 {
951 bfd_vma x = bfd_get_64 (abfd, (bfd_byte *) data + addr);
952 DOIT (x);
953 bfd_put_64 (abfd, x, (bfd_byte *) data + addr);
954 }
955 #else
956 abort ();
957 #endif
958 break;
959 default:
960 return bfd_reloc_other;
961 }
962
963 return flag;
964 }
965
966 /*
967 FUNCTION
968 bfd_install_relocation
969
970 SYNOPSIS
971 bfd_reloc_status_type
972 bfd_install_relocation
973 (bfd *abfd,
974 arelent *reloc_entry,
975 PTR data, bfd_vma data_start,
976 asection *input_section,
977 char **error_message);
978
979 DESCRIPTION
980 This looks remarkably like <<bfd_perform_relocation>>, except it
981 does not expect that the section contents have been filled in.
982 I.e., it's suitable for use when creating, rather than applying
983 a relocation.
984
985 For now, this function should be considered reserved for the
986 assembler.
987
988 */
989
990
991 bfd_reloc_status_type
992 bfd_install_relocation (abfd, reloc_entry, data_start, data_start_offset,
993 input_section, error_message)
994 bfd *abfd;
995 arelent *reloc_entry;
996 PTR data_start;
997 bfd_vma data_start_offset;
998 asection *input_section;
999 char **error_message;
1000 {
1001 bfd_vma relocation;
1002 bfd_reloc_status_type flag = bfd_reloc_ok;
1003 bfd_size_type addr = reloc_entry->address;
1004 bfd_vma output_base = 0;
1005 reloc_howto_type *howto = reloc_entry->howto;
1006 asection *reloc_target_output_section;
1007 asymbol *symbol;
1008 bfd_byte *data;
1009
1010 symbol = *(reloc_entry->sym_ptr_ptr);
1011 if (bfd_is_abs_section (symbol->section))
1012 {
1013 reloc_entry->address += input_section->output_offset;
1014 return bfd_reloc_ok;
1015 }
1016
1017 /* If there is a function supplied to handle this relocation type,
1018 call it. It'll return `bfd_reloc_continue' if further processing
1019 can be done. */
1020 if (howto->special_function)
1021 {
1022 bfd_reloc_status_type cont;
1023
1024 /* XXX - The special_function calls haven't been fixed up to deal
1025 with creating new relocations and section contents. */
1026 cont = howto->special_function (abfd, reloc_entry, symbol,
1027 /* XXX - Non-portable! */
1028 ((bfd_byte *) data_start
1029 - data_start_offset),
1030 input_section, abfd, error_message);
1031 if (cont != bfd_reloc_continue)
1032 return cont;
1033 }
1034
1035 /* Is the address of the relocation really within the section? */
1036 if (reloc_entry->address > input_section->_cooked_size)
1037 return bfd_reloc_outofrange;
1038
1039 /* Work out which section the relocation is targetted at and the
1040 initial relocation command value. */
1041
1042 /* Get symbol value. (Common symbols are special.) */
1043 if (bfd_is_com_section (symbol->section))
1044 relocation = 0;
1045 else
1046 relocation = symbol->value;
1047
1048 reloc_target_output_section = symbol->section->output_section;
1049
1050 /* Convert input-section-relative symbol value to absolute. */
1051 if (howto->partial_inplace == false)
1052 output_base = 0;
1053 else
1054 output_base = reloc_target_output_section->vma;
1055
1056 relocation += output_base + symbol->section->output_offset;
1057
1058 /* Add in supplied addend. */
1059 relocation += reloc_entry->addend;
1060
1061 /* Here the variable relocation holds the final address of the
1062 symbol we are relocating against, plus any addend. */
1063
1064 if (howto->pc_relative == true)
1065 {
1066 /* This is a PC relative relocation. We want to set RELOCATION
1067 to the distance between the address of the symbol and the
1068 location. RELOCATION is already the address of the symbol.
1069
1070 We start by subtracting the address of the section containing
1071 the location.
1072
1073 If pcrel_offset is set, we must further subtract the position
1074 of the location within the section. Some targets arrange for
1075 the addend to be the negative of the position of the location
1076 within the section; for example, i386-aout does this. For
1077 i386-aout, pcrel_offset is false. Some other targets do not
1078 include the position of the location; for example, m88kbcs,
1079 or ELF. For those targets, pcrel_offset is true.
1080
1081 If we are producing relocateable output, then we must ensure
1082 that this reloc will be correctly computed when the final
1083 relocation is done. If pcrel_offset is false we want to wind
1084 up with the negative of the location within the section,
1085 which means we must adjust the existing addend by the change
1086 in the location within the section. If pcrel_offset is true
1087 we do not want to adjust the existing addend at all.
1088
1089 FIXME: This seems logical to me, but for the case of
1090 producing relocateable output it is not what the code
1091 actually does. I don't want to change it, because it seems
1092 far too likely that something will break. */
1093
1094 relocation -=
1095 input_section->output_section->vma + input_section->output_offset;
1096
1097 if (howto->pcrel_offset == true && howto->partial_inplace == true)
1098 relocation -= reloc_entry->address;
1099 }
1100
1101 if (howto->partial_inplace == false)
1102 {
1103 /* This is a partial relocation, and we want to apply the relocation
1104 to the reloc entry rather than the raw data. Modify the reloc
1105 inplace to reflect what we now know. */
1106 reloc_entry->addend = relocation;
1107 reloc_entry->address += input_section->output_offset;
1108 return flag;
1109 }
1110 else
1111 {
1112 /* This is a partial relocation, but inplace, so modify the
1113 reloc record a bit.
1114
1115 If we've relocated with a symbol with a section, change
1116 into a ref to the section belonging to the symbol. */
1117
1118 reloc_entry->address += input_section->output_offset;
1119
1120 /* WTF?? */
1121 if (abfd->xvec->flavour == bfd_target_coff_flavour
1122 && strcmp (abfd->xvec->name, "aixcoff-rs6000") != 0
1123 && strcmp (abfd->xvec->name, "xcoff-powermac") != 0
1124 && strcmp (abfd->xvec->name, "coff-Intel-little") != 0
1125 && strcmp (abfd->xvec->name, "coff-Intel-big") != 0)
1126 {
1127 #if 1
1128 /* For m68k-coff, the addend was being subtracted twice during
1129 relocation with -r. Removing the line below this comment
1130 fixes that problem; see PR 2953.
1131
1132 However, Ian wrote the following, regarding removing the line below,
1133 which explains why it is still enabled: --djm
1134
1135 If you put a patch like that into BFD you need to check all the COFF
1136 linkers. I am fairly certain that patch will break coff-i386 (e.g.,
1137 SCO); see coff_i386_reloc in coff-i386.c where I worked around the
1138 problem in a different way. There may very well be a reason that the
1139 code works as it does.
1140
1141 Hmmm. The first obvious point is that bfd_install_relocation should
1142 not have any tests that depend upon the flavour. It's seem like
1143 entirely the wrong place for such a thing. The second obvious point
1144 is that the current code ignores the reloc addend when producing
1145 relocateable output for COFF. That's peculiar. In fact, I really
1146 have no idea what the point of the line you want to remove is.
1147
1148 A typical COFF reloc subtracts the old value of the symbol and adds in
1149 the new value to the location in the object file (if it's a pc
1150 relative reloc it adds the difference between the symbol value and the
1151 location). When relocating we need to preserve that property.
1152
1153 BFD handles this by setting the addend to the negative of the old
1154 value of the symbol. Unfortunately it handles common symbols in a
1155 non-standard way (it doesn't subtract the old value) but that's a
1156 different story (we can't change it without losing backward
1157 compatibility with old object files) (coff-i386 does subtract the old
1158 value, to be compatible with existing coff-i386 targets, like SCO).
1159
1160 So everything works fine when not producing relocateable output. When
1161 we are producing relocateable output, logically we should do exactly
1162 what we do when not producing relocateable output. Therefore, your
1163 patch is correct. In fact, it should probably always just set
1164 reloc_entry->addend to 0 for all cases, since it is, in fact, going to
1165 add the value into the object file. This won't hurt the COFF code,
1166 which doesn't use the addend; I'm not sure what it will do to other
1167 formats (the thing to check for would be whether any formats both use
1168 the addend and set partial_inplace).
1169
1170 When I wanted to make coff-i386 produce relocateable output, I ran
1171 into the problem that you are running into: I wanted to remove that
1172 line. Rather than risk it, I made the coff-i386 relocs use a special
1173 function; it's coff_i386_reloc in coff-i386.c. The function
1174 specifically adds the addend field into the object file, knowing that
1175 bfd_install_relocation is not going to. If you remove that line, then
1176 coff-i386.c will wind up adding the addend field in twice. It's
1177 trivial to fix; it just needs to be done.
1178
1179 The problem with removing the line is just that it may break some
1180 working code. With BFD it's hard to be sure of anything. The right
1181 way to deal with this is simply to build and test at least all the
1182 supported COFF targets. It should be straightforward if time and disk
1183 space consuming. For each target:
1184 1) build the linker
1185 2) generate some executable, and link it using -r (I would
1186 probably use paranoia.o and link against newlib/libc.a, which
1187 for all the supported targets would be available in
1188 /usr/cygnus/progressive/H-host/target/lib/libc.a).
1189 3) make the change to reloc.c
1190 4) rebuild the linker
1191 5) repeat step 2
1192 6) if the resulting object files are the same, you have at least
1193 made it no worse
1194 7) if they are different you have to figure out which version is
1195 right
1196 */
1197 relocation -= reloc_entry->addend;
1198 #endif
1199 reloc_entry->addend = 0;
1200 }
1201 else
1202 {
1203 reloc_entry->addend = relocation;
1204 }
1205 }
1206
1207 /* FIXME: This overflow checking is incomplete, because the value
1208 might have overflowed before we get here. For a correct check we
1209 need to compute the value in a size larger than bitsize, but we
1210 can't reasonably do that for a reloc the same size as a host
1211 machine word.
1212 FIXME: We should also do overflow checking on the result after
1213 adding in the value contained in the object file. */
1214 if (howto->complain_on_overflow != complain_overflow_dont)
1215 flag = bfd_check_overflow (howto->complain_on_overflow, howto->bitsize,
1216 howto->rightshift, relocation);
1217
1218 /*
1219 Either we are relocating all the way, or we don't want to apply
1220 the relocation to the reloc entry (probably because there isn't
1221 any room in the output format to describe addends to relocs)
1222 */
1223
1224 /* The cast to bfd_vma avoids a bug in the Alpha OSF/1 C compiler
1225 (OSF version 1.3, compiler version 3.11). It miscompiles the
1226 following program:
1227
1228 struct str
1229 {
1230 unsigned int i0;
1231 } s = { 0 };
1232
1233 int
1234 main ()
1235 {
1236 unsigned long x;
1237
1238 x = 0x100000000;
1239 x <<= (unsigned long) s.i0;
1240 if (x == 0)
1241 printf ("failed\n");
1242 else
1243 printf ("succeeded (%lx)\n", x);
1244 }
1245 */
1246
1247 relocation >>= (bfd_vma) howto->rightshift;
1248
1249 /* Shift everything up to where it's going to be used */
1250
1251 relocation <<= (bfd_vma) howto->bitpos;
1252
1253 /* Wait for the day when all have the mask in them */
1254
1255 /* What we do:
1256 i instruction to be left alone
1257 o offset within instruction
1258 r relocation offset to apply
1259 S src mask
1260 D dst mask
1261 N ~dst mask
1262 A part 1
1263 B part 2
1264 R result
1265
1266 Do this:
1267 i i i i i o o o o o from bfd_get<size>
1268 and S S S S S to get the size offset we want
1269 + r r r r r r r r r r to get the final value to place
1270 and D D D D D to chop to right size
1271 -----------------------
1272 A A A A A
1273 And this:
1274 ... i i i i i o o o o o from bfd_get<size>
1275 and N N N N N get instruction
1276 -----------------------
1277 ... B B B B B
1278
1279 And then:
1280 B B B B B
1281 or A A A A A
1282 -----------------------
1283 R R R R R R R R R R put into bfd_put<size>
1284 */
1285
1286 #define DOIT(x) \
1287 x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) + relocation) & howto->dst_mask))
1288
1289 data = (bfd_byte *) data_start + (addr - data_start_offset);
1290
1291 switch (howto->size)
1292 {
1293 case 0:
1294 {
1295 char x = bfd_get_8 (abfd, (char *) data);
1296 DOIT (x);
1297 bfd_put_8 (abfd, x, (unsigned char *) data);
1298 }
1299 break;
1300
1301 case 1:
1302 {
1303 short x = bfd_get_16 (abfd, (bfd_byte *) data);
1304 DOIT (x);
1305 bfd_put_16 (abfd, x, (unsigned char *) data);
1306 }
1307 break;
1308 case 2:
1309 {
1310 long x = bfd_get_32 (abfd, (bfd_byte *) data);
1311 DOIT (x);
1312 bfd_put_32 (abfd, x, (bfd_byte *) data);
1313 }
1314 break;
1315 case -2:
1316 {
1317 long x = bfd_get_32 (abfd, (bfd_byte *) data);
1318 relocation = -relocation;
1319 DOIT (x);
1320 bfd_put_32 (abfd, x, (bfd_byte *) data);
1321 }
1322 break;
1323
1324 case 3:
1325 /* Do nothing */
1326 break;
1327
1328 case 4:
1329 {
1330 bfd_vma x = bfd_get_64 (abfd, (bfd_byte *) data);
1331 DOIT (x);
1332 bfd_put_64 (abfd, x, (bfd_byte *) data);
1333 }
1334 break;
1335 default:
1336 return bfd_reloc_other;
1337 }
1338
1339 return flag;
1340 }
1341
1342 /* This relocation routine is used by some of the backend linkers.
1343 They do not construct asymbol or arelent structures, so there is no
1344 reason for them to use bfd_perform_relocation. Also,
1345 bfd_perform_relocation is so hacked up it is easier to write a new
1346 function than to try to deal with it.
1347
1348 This routine does a final relocation. Whether it is useful for a
1349 relocateable link depends upon how the object format defines
1350 relocations.
1351
1352 FIXME: This routine ignores any special_function in the HOWTO,
1353 since the existing special_function values have been written for
1354 bfd_perform_relocation.
1355
1356 HOWTO is the reloc howto information.
1357 INPUT_BFD is the BFD which the reloc applies to.
1358 INPUT_SECTION is the section which the reloc applies to.
1359 CONTENTS is the contents of the section.
1360 ADDRESS is the address of the reloc within INPUT_SECTION.
1361 VALUE is the value of the symbol the reloc refers to.
1362 ADDEND is the addend of the reloc. */
1363
1364 bfd_reloc_status_type
1365 _bfd_final_link_relocate (howto, input_bfd, input_section, contents, address,
1366 value, addend)
1367 reloc_howto_type *howto;
1368 bfd *input_bfd;
1369 asection *input_section;
1370 bfd_byte *contents;
1371 bfd_vma address;
1372 bfd_vma value;
1373 bfd_vma addend;
1374 {
1375 bfd_vma relocation;
1376
1377 /* Sanity check the address. */
1378 if (address > input_section->_raw_size)
1379 return bfd_reloc_outofrange;
1380
1381 /* This function assumes that we are dealing with a basic relocation
1382 against a symbol. We want to compute the value of the symbol to
1383 relocate to. This is just VALUE, the value of the symbol, plus
1384 ADDEND, any addend associated with the reloc. */
1385 relocation = value + addend;
1386
1387 /* If the relocation is PC relative, we want to set RELOCATION to
1388 the distance between the symbol (currently in RELOCATION) and the
1389 location we are relocating. Some targets (e.g., i386-aout)
1390 arrange for the contents of the section to be the negative of the
1391 offset of the location within the section; for such targets
1392 pcrel_offset is false. Other targets (e.g., m88kbcs or ELF)
1393 simply leave the contents of the section as zero; for such
1394 targets pcrel_offset is true. If pcrel_offset is false we do not
1395 need to subtract out the offset of the location within the
1396 section (which is just ADDRESS). */
1397 if (howto->pc_relative)
1398 {
1399 relocation -= (input_section->output_section->vma
1400 + input_section->output_offset);
1401 if (howto->pcrel_offset)
1402 relocation -= address;
1403 }
1404
1405 return _bfd_relocate_contents (howto, input_bfd, relocation,
1406 contents + address);
1407 }
1408
1409 /* Relocate a given location using a given value and howto. */
1410
1411 bfd_reloc_status_type
1412 _bfd_relocate_contents (howto, input_bfd, relocation, location)
1413 reloc_howto_type *howto;
1414 bfd *input_bfd;
1415 bfd_vma relocation;
1416 bfd_byte *location;
1417 {
1418 int size;
1419 bfd_vma x;
1420 boolean overflow;
1421
1422 /* If the size is negative, negate RELOCATION. This isn't very
1423 general. */
1424 if (howto->size < 0)
1425 relocation = -relocation;
1426
1427 /* Get the value we are going to relocate. */
1428 size = bfd_get_reloc_size (howto);
1429 switch (size)
1430 {
1431 default:
1432 case 0:
1433 abort ();
1434 case 1:
1435 x = bfd_get_8 (input_bfd, location);
1436 break;
1437 case 2:
1438 x = bfd_get_16 (input_bfd, location);
1439 break;
1440 case 4:
1441 x = bfd_get_32 (input_bfd, location);
1442 break;
1443 case 8:
1444 #ifdef BFD64
1445 x = bfd_get_64 (input_bfd, location);
1446 #else
1447 abort ();
1448 #endif
1449 break;
1450 }
1451
1452 /* Check for overflow. FIXME: We may drop bits during the addition
1453 which we don't check for. We must either check at every single
1454 operation, which would be tedious, or we must do the computations
1455 in a type larger than bfd_vma, which would be inefficient. */
1456 overflow = false;
1457 if (howto->complain_on_overflow != complain_overflow_dont)
1458 {
1459 bfd_vma check;
1460 bfd_signed_vma signed_check;
1461 bfd_vma add;
1462 bfd_signed_vma signed_add;
1463
1464 if (howto->rightshift == 0)
1465 {
1466 check = relocation;
1467 signed_check = (bfd_signed_vma) relocation;
1468 }
1469 else
1470 {
1471 /* Drop unwanted bits from the value we are relocating to. */
1472 check = relocation >> howto->rightshift;
1473
1474 /* If this is a signed value, the rightshift just dropped
1475 leading 1 bits (assuming twos complement). */
1476 if ((bfd_signed_vma) relocation >= 0)
1477 signed_check = check;
1478 else
1479 signed_check = (check
1480 | ((bfd_vma) - 1
1481 & ~((bfd_vma) - 1 >> howto->rightshift)));
1482 }
1483
1484 /* Get the value from the object file. */
1485 add = x & howto->src_mask;
1486
1487 /* Get the value from the object file with an appropriate sign.
1488 The expression involving howto->src_mask isolates the upper
1489 bit of src_mask. If that bit is set in the value we are
1490 adding, it is negative, and we subtract out that number times
1491 two. If src_mask includes the highest possible bit, then we
1492 can not get the upper bit, but that does not matter since
1493 signed_add needs no adjustment to become negative in that
1494 case. */
1495 signed_add = add;
1496 if ((add & (((~howto->src_mask) >> 1) & howto->src_mask)) != 0)
1497 signed_add -= (((~howto->src_mask) >> 1) & howto->src_mask) << 1;
1498
1499 /* Add the value from the object file, shifted so that it is a
1500 straight number. */
1501 if (howto->bitpos == 0)
1502 {
1503 check += add;
1504 signed_check += signed_add;
1505 }
1506 else
1507 {
1508 check += add >> howto->bitpos;
1509
1510 /* For the signed case we use ADD, rather than SIGNED_ADD,
1511 to avoid warnings from SVR4 cc. This is OK since we
1512 explictly handle the sign bits. */
1513 if (signed_add >= 0)
1514 signed_check += add >> howto->bitpos;
1515 else
1516 signed_check += ((add >> howto->bitpos)
1517 | ((bfd_vma) - 1
1518 & ~((bfd_vma) - 1 >> howto->bitpos)));
1519 }
1520
1521 switch (howto->complain_on_overflow)
1522 {
1523 case complain_overflow_signed:
1524 {
1525 /* Assumes two's complement. */
1526 bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
1527 bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
1528
1529 if (signed_check > reloc_signed_max
1530 || signed_check < reloc_signed_min)
1531 overflow = true;
1532 }
1533 break;
1534 case complain_overflow_unsigned:
1535 {
1536 /* Assumes two's complement. This expression avoids
1537 overflow if howto->bitsize is the number of bits in
1538 bfd_vma. */
1539 bfd_vma reloc_unsigned_max =
1540 (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1541
1542 if (check > reloc_unsigned_max)
1543 overflow = true;
1544 }
1545 break;
1546 case complain_overflow_bitfield:
1547 {
1548 /* Assumes two's complement. This expression avoids
1549 overflow if howto->bitsize is the number of bits in
1550 bfd_vma. */
1551 bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1552
1553 if ((check & ~reloc_bits) != 0
1554 && (((bfd_vma) signed_check & ~reloc_bits)
1555 != (-1 & ~reloc_bits)))
1556 overflow = true;
1557 }
1558 break;
1559 default:
1560 abort ();
1561 }
1562 }
1563
1564 /* Put RELOCATION in the right bits. */
1565 relocation >>= (bfd_vma) howto->rightshift;
1566 relocation <<= (bfd_vma) howto->bitpos;
1567
1568 /* Add RELOCATION to the right bits of X. */
1569 x = ((x & ~howto->dst_mask)
1570 | (((x & howto->src_mask) + relocation) & howto->dst_mask));
1571
1572 /* Put the relocated value back in the object file. */
1573 switch (size)
1574 {
1575 default:
1576 case 0:
1577 abort ();
1578 case 1:
1579 bfd_put_8 (input_bfd, x, location);
1580 break;
1581 case 2:
1582 bfd_put_16 (input_bfd, x, location);
1583 break;
1584 case 4:
1585 bfd_put_32 (input_bfd, x, location);
1586 break;
1587 case 8:
1588 #ifdef BFD64
1589 bfd_put_64 (input_bfd, x, location);
1590 #else
1591 abort ();
1592 #endif
1593 break;
1594 }
1595
1596 return overflow ? bfd_reloc_overflow : bfd_reloc_ok;
1597 }
1598
1599 /*
1600 DOCDD
1601 INODE
1602 howto manager, , typedef arelent, Relocations
1603
1604 SECTION
1605 The howto manager
1606
1607 When an application wants to create a relocation, but doesn't
1608 know what the target machine might call it, it can find out by
1609 using this bit of code.
1610
1611 */
1612
1613 /*
1614 TYPEDEF
1615 bfd_reloc_code_type
1616
1617 DESCRIPTION
1618 The insides of a reloc code. The idea is that, eventually, there
1619 will be one enumerator for every type of relocation we ever do.
1620 Pass one of these values to <<bfd_reloc_type_lookup>>, and it'll
1621 return a howto pointer.
1622
1623 This does mean that the application must determine the correct
1624 enumerator value; you can't get a howto pointer from a random set
1625 of attributes.
1626
1627 SENUM
1628 bfd_reloc_code_real
1629
1630 ENUM
1631 BFD_RELOC_64
1632 ENUMX
1633 BFD_RELOC_32
1634 ENUMX
1635 BFD_RELOC_26
1636 ENUMX
1637 BFD_RELOC_24
1638 ENUMX
1639 BFD_RELOC_16
1640 ENUMX
1641 BFD_RELOC_14
1642 ENUMX
1643 BFD_RELOC_8
1644 ENUMDOC
1645 Basic absolute relocations of N bits.
1646
1647 ENUM
1648 BFD_RELOC_64_PCREL
1649 ENUMX
1650 BFD_RELOC_32_PCREL
1651 ENUMX
1652 BFD_RELOC_24_PCREL
1653 ENUMX
1654 BFD_RELOC_16_PCREL
1655 ENUMX
1656 BFD_RELOC_12_PCREL
1657 ENUMX
1658 BFD_RELOC_8_PCREL
1659 ENUMDOC
1660 PC-relative relocations. Sometimes these are relative to the address
1661 of the relocation itself; sometimes they are relative to the start of
1662 the section containing the relocation. It depends on the specific target.
1663
1664 The 24-bit relocation is used in some Intel 960 configurations.
1665
1666 ENUM
1667 BFD_RELOC_32_GOT_PCREL
1668 ENUMX
1669 BFD_RELOC_16_GOT_PCREL
1670 ENUMX
1671 BFD_RELOC_8_GOT_PCREL
1672 ENUMX
1673 BFD_RELOC_32_GOTOFF
1674 ENUMX
1675 BFD_RELOC_16_GOTOFF
1676 ENUMX
1677 BFD_RELOC_LO16_GOTOFF
1678 ENUMX
1679 BFD_RELOC_HI16_GOTOFF
1680 ENUMX
1681 BFD_RELOC_HI16_S_GOTOFF
1682 ENUMX
1683 BFD_RELOC_8_GOTOFF
1684 ENUMX
1685 BFD_RELOC_32_PLT_PCREL
1686 ENUMX
1687 BFD_RELOC_24_PLT_PCREL
1688 ENUMX
1689 BFD_RELOC_16_PLT_PCREL
1690 ENUMX
1691 BFD_RELOC_8_PLT_PCREL
1692 ENUMX
1693 BFD_RELOC_32_PLTOFF
1694 ENUMX
1695 BFD_RELOC_16_PLTOFF
1696 ENUMX
1697 BFD_RELOC_LO16_PLTOFF
1698 ENUMX
1699 BFD_RELOC_HI16_PLTOFF
1700 ENUMX
1701 BFD_RELOC_HI16_S_PLTOFF
1702 ENUMX
1703 BFD_RELOC_8_PLTOFF
1704 ENUMDOC
1705 For ELF.
1706
1707 ENUM
1708 BFD_RELOC_68K_GLOB_DAT
1709 ENUMX
1710 BFD_RELOC_68K_JMP_SLOT
1711 ENUMX
1712 BFD_RELOC_68K_RELATIVE
1713 ENUMDOC
1714 Relocations used by 68K ELF.
1715
1716 ENUM
1717 BFD_RELOC_32_BASEREL
1718 ENUMX
1719 BFD_RELOC_16_BASEREL
1720 ENUMX
1721 BFD_RELOC_LO16_BASEREL
1722 ENUMX
1723 BFD_RELOC_HI16_BASEREL
1724 ENUMX
1725 BFD_RELOC_HI16_S_BASEREL
1726 ENUMX
1727 BFD_RELOC_8_BASEREL
1728 ENUMX
1729 BFD_RELOC_RVA
1730 ENUMDOC
1731 Linkage-table relative.
1732
1733 ENUM
1734 BFD_RELOC_8_FFnn
1735 ENUMDOC
1736 Absolute 8-bit relocation, but used to form an address like 0xFFnn.
1737
1738 ENUM
1739 BFD_RELOC_32_PCREL_S2
1740 ENUMX
1741 BFD_RELOC_16_PCREL_S2
1742 ENUMX
1743 BFD_RELOC_23_PCREL_S2
1744 ENUMDOC
1745 These PC-relative relocations are stored as word displacements --
1746 i.e., byte displacements shifted right two bits. The 30-bit word
1747 displacement (<<32_PCREL_S2>> -- 32 bits, shifted 2) is used on the
1748 SPARC. (SPARC tools generally refer to this as <<WDISP30>>.) The
1749 signed 16-bit displacement is used on the MIPS, and the 23-bit
1750 displacement is used on the Alpha.
1751
1752 ENUM
1753 BFD_RELOC_HI22
1754 ENUMX
1755 BFD_RELOC_LO10
1756 ENUMDOC
1757 High 22 bits and low 10 bits of 32-bit value, placed into lower bits of
1758 the target word. These are used on the SPARC.
1759
1760 ENUM
1761 BFD_RELOC_GPREL16
1762 ENUMX
1763 BFD_RELOC_GPREL32
1764 ENUMDOC
1765 For systems that allocate a Global Pointer register, these are
1766 displacements off that register. These relocation types are
1767 handled specially, because the value the register will have is
1768 decided relatively late.
1769
1770
1771 ENUM
1772 BFD_RELOC_I960_CALLJ
1773 ENUMDOC
1774 Reloc types used for i960/b.out.
1775
1776 ENUM
1777 BFD_RELOC_NONE
1778 ENUMX
1779 BFD_RELOC_SPARC_WDISP22
1780 ENUMX
1781 BFD_RELOC_SPARC22
1782 ENUMX
1783 BFD_RELOC_SPARC13
1784 ENUMX
1785 BFD_RELOC_SPARC_GOT10
1786 ENUMX
1787 BFD_RELOC_SPARC_GOT13
1788 ENUMX
1789 BFD_RELOC_SPARC_GOT22
1790 ENUMX
1791 BFD_RELOC_SPARC_PC10
1792 ENUMX
1793 BFD_RELOC_SPARC_PC22
1794 ENUMX
1795 BFD_RELOC_SPARC_WPLT30
1796 ENUMX
1797 BFD_RELOC_SPARC_COPY
1798 ENUMX
1799 BFD_RELOC_SPARC_GLOB_DAT
1800 ENUMX
1801 BFD_RELOC_SPARC_JMP_SLOT
1802 ENUMX
1803 BFD_RELOC_SPARC_RELATIVE
1804 ENUMX
1805 BFD_RELOC_SPARC_UA32
1806 ENUMDOC
1807 SPARC ELF relocations. There is probably some overlap with other
1808 relocation types already defined.
1809
1810 ENUM
1811 BFD_RELOC_SPARC_BASE13
1812 ENUMX
1813 BFD_RELOC_SPARC_BASE22
1814 ENUMDOC
1815 I think these are specific to SPARC a.out (e.g., Sun 4).
1816
1817 ENUMEQ
1818 BFD_RELOC_SPARC_64
1819 BFD_RELOC_64
1820 ENUMX
1821 BFD_RELOC_SPARC_10
1822 ENUMX
1823 BFD_RELOC_SPARC_11
1824 ENUMX
1825 BFD_RELOC_SPARC_OLO10
1826 ENUMX
1827 BFD_RELOC_SPARC_HH22
1828 ENUMX
1829 BFD_RELOC_SPARC_HM10
1830 ENUMX
1831 BFD_RELOC_SPARC_LM22
1832 ENUMX
1833 BFD_RELOC_SPARC_PC_HH22
1834 ENUMX
1835 BFD_RELOC_SPARC_PC_HM10
1836 ENUMX
1837 BFD_RELOC_SPARC_PC_LM22
1838 ENUMX
1839 BFD_RELOC_SPARC_WDISP16
1840 ENUMX
1841 BFD_RELOC_SPARC_WDISP19
1842 ENUMX
1843 BFD_RELOC_SPARC_7
1844 ENUMX
1845 BFD_RELOC_SPARC_6
1846 ENUMX
1847 BFD_RELOC_SPARC_5
1848 ENUMEQX
1849 BFD_RELOC_SPARC_DISP64
1850 BFD_RELOC_64_PCREL
1851 ENUMX
1852 BFD_RELOC_SPARC_PLT64
1853 ENUMX
1854 BFD_RELOC_SPARC_HIX22
1855 ENUMX
1856 BFD_RELOC_SPARC_LOX10
1857 ENUMX
1858 BFD_RELOC_SPARC_H44
1859 ENUMX
1860 BFD_RELOC_SPARC_M44
1861 ENUMX
1862 BFD_RELOC_SPARC_L44
1863 ENUMX
1864 BFD_RELOC_SPARC_REGISTER
1865 ENUMDOC
1866 SPARC64 relocations
1867
1868 ENUM
1869 BFD_RELOC_ALPHA_GPDISP_HI16
1870 ENUMDOC
1871 Alpha ECOFF and ELF relocations. Some of these treat the symbol or
1872 "addend" in some special way.
1873 For GPDISP_HI16 ("gpdisp") relocations, the symbol is ignored when
1874 writing; when reading, it will be the absolute section symbol. The
1875 addend is the displacement in bytes of the "lda" instruction from
1876 the "ldah" instruction (which is at the address of this reloc).
1877 ENUM
1878 BFD_RELOC_ALPHA_GPDISP_LO16
1879 ENUMDOC
1880 For GPDISP_LO16 ("ignore") relocations, the symbol is handled as
1881 with GPDISP_HI16 relocs. The addend is ignored when writing the
1882 relocations out, and is filled in with the file's GP value on
1883 reading, for convenience.
1884
1885 ENUM
1886 BFD_RELOC_ALPHA_GPDISP
1887 ENUMDOC
1888 The ELF GPDISP relocation is exactly the same as the GPDISP_HI16
1889 relocation except that there is no accompanying GPDISP_LO16
1890 relocation.
1891
1892 ENUM
1893 BFD_RELOC_ALPHA_LITERAL
1894 ENUMX
1895 BFD_RELOC_ALPHA_ELF_LITERAL
1896 ENUMX
1897 BFD_RELOC_ALPHA_LITUSE
1898 ENUMDOC
1899 The Alpha LITERAL/LITUSE relocs are produced by a symbol reference;
1900 the assembler turns it into a LDQ instruction to load the address of
1901 the symbol, and then fills in a register in the real instruction.
1902
1903 The LITERAL reloc, at the LDQ instruction, refers to the .lita
1904 section symbol. The addend is ignored when writing, but is filled
1905 in with the file's GP value on reading, for convenience, as with the
1906 GPDISP_LO16 reloc.
1907
1908 The ELF_LITERAL reloc is somewhere between 16_GOTOFF and GPDISP_LO16.
1909 It should refer to the symbol to be referenced, as with 16_GOTOFF,
1910 but it generates output not based on the position within the .got
1911 section, but relative to the GP value chosen for the file during the
1912 final link stage.
1913
1914 The LITUSE reloc, on the instruction using the loaded address, gives
1915 information to the linker that it might be able to use to optimize
1916 away some literal section references. The symbol is ignored (read
1917 as the absolute section symbol), and the "addend" indicates the type
1918 of instruction using the register:
1919 1 - "memory" fmt insn
1920 2 - byte-manipulation (byte offset reg)
1921 3 - jsr (target of branch)
1922
1923 The GNU linker currently doesn't do any of this optimizing.
1924
1925 ENUM
1926 BFD_RELOC_ALPHA_HINT
1927 ENUMDOC
1928 The HINT relocation indicates a value that should be filled into the
1929 "hint" field of a jmp/jsr/ret instruction, for possible branch-
1930 prediction logic which may be provided on some processors.
1931
1932 ENUM
1933 BFD_RELOC_ALPHA_LINKAGE
1934 ENUMDOC
1935 The LINKAGE relocation outputs a linkage pair in the object file,
1936 which is filled by the linker.
1937
1938 ENUM
1939 BFD_RELOC_ALPHA_CODEADDR
1940 ENUMDOC
1941 The CODEADDR relocation outputs a STO_CA in the object file,
1942 which is filled by the linker.
1943
1944 ENUM
1945 BFD_RELOC_MIPS_JMP
1946 ENUMDOC
1947 Bits 27..2 of the relocation address shifted right 2 bits;
1948 simple reloc otherwise.
1949
1950 ENUM
1951 BFD_RELOC_MIPS16_JMP
1952 ENUMDOC
1953 The MIPS16 jump instruction.
1954
1955 ENUM
1956 BFD_RELOC_MIPS16_GPREL
1957 ENUMDOC
1958 MIPS16 GP relative reloc.
1959
1960 ENUM
1961 BFD_RELOC_HI16
1962 ENUMDOC
1963 High 16 bits of 32-bit value; simple reloc.
1964 ENUM
1965 BFD_RELOC_HI16_S
1966 ENUMDOC
1967 High 16 bits of 32-bit value but the low 16 bits will be sign
1968 extended and added to form the final result. If the low 16
1969 bits form a negative number, we need to add one to the high value
1970 to compensate for the borrow when the low bits are added.
1971 ENUM
1972 BFD_RELOC_LO16
1973 ENUMDOC
1974 Low 16 bits.
1975 ENUM
1976 BFD_RELOC_PCREL_HI16_S
1977 ENUMDOC
1978 Like BFD_RELOC_HI16_S, but PC relative.
1979 ENUM
1980 BFD_RELOC_PCREL_LO16
1981 ENUMDOC
1982 Like BFD_RELOC_LO16, but PC relative.
1983
1984 ENUMEQ
1985 BFD_RELOC_MIPS_GPREL
1986 BFD_RELOC_GPREL16
1987 ENUMDOC
1988 Relocation relative to the global pointer.
1989
1990 ENUM
1991 BFD_RELOC_MIPS_LITERAL
1992 ENUMDOC
1993 Relocation against a MIPS literal section.
1994
1995 ENUM
1996 BFD_RELOC_MIPS_GOT16
1997 ENUMX
1998 BFD_RELOC_MIPS_CALL16
1999 ENUMEQX
2000 BFD_RELOC_MIPS_GPREL32
2001 BFD_RELOC_GPREL32
2002 ENUMX
2003 BFD_RELOC_MIPS_GOT_HI16
2004 ENUMX
2005 BFD_RELOC_MIPS_GOT_LO16
2006 ENUMX
2007 BFD_RELOC_MIPS_CALL_HI16
2008 ENUMX
2009 BFD_RELOC_MIPS_CALL_LO16
2010 ENUMDOC
2011 MIPS ELF relocations.
2012
2013 COMMENT
2014 {* start-sanitize-sky *}
2015 ENUM
2016 BFD_RELOC_MIPS_DVP_11_PCREL
2017 ENUMDOC
2018 MIPS DVP Relocations.
2019 This is an 11-bit pc relative reloc. The recorded address is for the
2020 lower instruction word, and the value is in 128 bit units.
2021 COMMENT
2022 {* end-sanitize-sky *}
2023
2024 ENUM
2025 BFD_RELOC_386_GOT32
2026 ENUMX
2027 BFD_RELOC_386_PLT32
2028 ENUMX
2029 BFD_RELOC_386_COPY
2030 ENUMX
2031 BFD_RELOC_386_GLOB_DAT
2032 ENUMX
2033 BFD_RELOC_386_JUMP_SLOT
2034 ENUMX
2035 BFD_RELOC_386_RELATIVE
2036 ENUMX
2037 BFD_RELOC_386_GOTOFF
2038 ENUMX
2039 BFD_RELOC_386_GOTPC
2040 ENUMDOC
2041 i386/elf relocations
2042
2043 ENUM
2044 BFD_RELOC_NS32K_IMM_8
2045 ENUMX
2046 BFD_RELOC_NS32K_IMM_16
2047 ENUMX
2048 BFD_RELOC_NS32K_IMM_32
2049 ENUMX
2050 BFD_RELOC_NS32K_IMM_8_PCREL
2051 ENUMX
2052 BFD_RELOC_NS32K_IMM_16_PCREL
2053 ENUMX
2054 BFD_RELOC_NS32K_IMM_32_PCREL
2055 ENUMX
2056 BFD_RELOC_NS32K_DISP_8
2057 ENUMX
2058 BFD_RELOC_NS32K_DISP_16
2059 ENUMX
2060 BFD_RELOC_NS32K_DISP_32
2061 ENUMX
2062 BFD_RELOC_NS32K_DISP_8_PCREL
2063 ENUMX
2064 BFD_RELOC_NS32K_DISP_16_PCREL
2065 ENUMX
2066 BFD_RELOC_NS32K_DISP_32_PCREL
2067 ENUMDOC
2068 ns32k relocations
2069
2070 ENUM
2071 BFD_RELOC_PPC_B26
2072 ENUMX
2073 BFD_RELOC_PPC_BA26
2074 ENUMX
2075 BFD_RELOC_PPC_TOC16
2076 ENUMX
2077 BFD_RELOC_PPC_B16
2078 ENUMX
2079 BFD_RELOC_PPC_B16_BRTAKEN
2080 ENUMX
2081 BFD_RELOC_PPC_B16_BRNTAKEN
2082 ENUMX
2083 BFD_RELOC_PPC_BA16
2084 ENUMX
2085 BFD_RELOC_PPC_BA16_BRTAKEN
2086 ENUMX
2087 BFD_RELOC_PPC_BA16_BRNTAKEN
2088 ENUMX
2089 BFD_RELOC_PPC_COPY
2090 ENUMX
2091 BFD_RELOC_PPC_GLOB_DAT
2092 ENUMX
2093 BFD_RELOC_PPC_JMP_SLOT
2094 ENUMX
2095 BFD_RELOC_PPC_RELATIVE
2096 ENUMX
2097 BFD_RELOC_PPC_LOCAL24PC
2098 ENUMX
2099 BFD_RELOC_PPC_EMB_NADDR32
2100 ENUMX
2101 BFD_RELOC_PPC_EMB_NADDR16
2102 ENUMX
2103 BFD_RELOC_PPC_EMB_NADDR16_LO
2104 ENUMX
2105 BFD_RELOC_PPC_EMB_NADDR16_HI
2106 ENUMX
2107 BFD_RELOC_PPC_EMB_NADDR16_HA
2108 ENUMX
2109 BFD_RELOC_PPC_EMB_SDAI16
2110 ENUMX
2111 BFD_RELOC_PPC_EMB_SDA2I16
2112 ENUMX
2113 BFD_RELOC_PPC_EMB_SDA2REL
2114 ENUMX
2115 BFD_RELOC_PPC_EMB_SDA21
2116 ENUMX
2117 BFD_RELOC_PPC_EMB_MRKREF
2118 ENUMX
2119 BFD_RELOC_PPC_EMB_RELSEC16
2120 ENUMX
2121 BFD_RELOC_PPC_EMB_RELST_LO
2122 ENUMX
2123 BFD_RELOC_PPC_EMB_RELST_HI
2124 ENUMX
2125 BFD_RELOC_PPC_EMB_RELST_HA
2126 ENUMX
2127 BFD_RELOC_PPC_EMB_BIT_FLD
2128 ENUMX
2129 BFD_RELOC_PPC_EMB_RELSDA
2130 ENUMDOC
2131 Power(rs6000) and PowerPC relocations.
2132
2133 ENUM
2134 BFD_RELOC_CTOR
2135 ENUMDOC
2136 The type of reloc used to build a contructor table - at the moment
2137 probably a 32 bit wide absolute relocation, but the target can choose.
2138 It generally does map to one of the other relocation types.
2139
2140 ENUM
2141 BFD_RELOC_ARM_PCREL_BRANCH
2142 ENUMDOC
2143 ARM 26 bit pc-relative branch. The lowest two bits must be zero and are
2144 not stored in the instruction.
2145 ENUM
2146 BFD_RELOC_ARM_IMMEDIATE
2147 ENUMX
2148 BFD_RELOC_ARM_OFFSET_IMM
2149 ENUMX
2150 BFD_RELOC_ARM_SHIFT_IMM
2151 ENUMX
2152 BFD_RELOC_ARM_SWI
2153 ENUMX
2154 BFD_RELOC_ARM_MULTI
2155 ENUMX
2156 BFD_RELOC_ARM_CP_OFF_IMM
2157 ENUMX
2158 BFD_RELOC_ARM_ADR_IMM
2159 ENUMX
2160 BFD_RELOC_ARM_LDR_IMM
2161 ENUMX
2162 BFD_RELOC_ARM_LITERAL
2163 ENUMX
2164 BFD_RELOC_ARM_IN_POOL
2165 ENUMX
2166 BFD_RELOC_ARM_OFFSET_IMM8
2167 ENUMX
2168 BFD_RELOC_ARM_HWLITERAL
2169 ENUMX
2170 BFD_RELOC_ARM_THUMB_ADD
2171 ENUMX
2172 BFD_RELOC_ARM_THUMB_IMM
2173 ENUMX
2174 BFD_RELOC_ARM_THUMB_SHIFT
2175 ENUMX
2176 BFD_RELOC_ARM_THUMB_OFFSET
2177 ENUMDOC
2178 These relocs are only used within the ARM assembler. They are not
2179 (at present) written to any object files.
2180
2181 ENUM
2182 BFD_RELOC_SH_PCDISP8BY2
2183 ENUMX
2184 BFD_RELOC_SH_PCDISP12BY2
2185 ENUMX
2186 BFD_RELOC_SH_IMM4
2187 ENUMX
2188 BFD_RELOC_SH_IMM4BY2
2189 ENUMX
2190 BFD_RELOC_SH_IMM4BY4
2191 ENUMX
2192 BFD_RELOC_SH_IMM8
2193 ENUMX
2194 BFD_RELOC_SH_IMM8BY2
2195 ENUMX
2196 BFD_RELOC_SH_IMM8BY4
2197 ENUMX
2198 BFD_RELOC_SH_PCRELIMM8BY2
2199 ENUMX
2200 BFD_RELOC_SH_PCRELIMM8BY4
2201 ENUMX
2202 BFD_RELOC_SH_SWITCH16
2203 ENUMX
2204 BFD_RELOC_SH_SWITCH32
2205 ENUMX
2206 BFD_RELOC_SH_USES
2207 ENUMX
2208 BFD_RELOC_SH_COUNT
2209 ENUMX
2210 BFD_RELOC_SH_ALIGN
2211 ENUMX
2212 BFD_RELOC_SH_CODE
2213 ENUMX
2214 BFD_RELOC_SH_DATA
2215 ENUMX
2216 BFD_RELOC_SH_LABEL
2217 ENUMDOC
2218 Hitachi SH relocs. Not all of these appear in object files.
2219
2220 ENUM
2221 BFD_RELOC_THUMB_PCREL_BRANCH9
2222 ENUMX
2223 BFD_RELOC_THUMB_PCREL_BRANCH12
2224 ENUMX
2225 BFD_RELOC_THUMB_PCREL_BRANCH23
2226 ENUMDOC
2227 Thumb 23-, 12- and 9-bit pc-relative branches. The lowest bit must
2228 be zero and is not stored in the instruction.
2229
2230 ENUM
2231 BFD_RELOC_ARC_B22_PCREL
2232 ENUMDOC
2233 Argonaut RISC Core (ARC) relocs.
2234 ARC 22 bit pc-relative branch. The lowest two bits must be zero and are
2235 not stored in the instruction. The high 20 bits are installed in bits 26
2236 through 7 of the instruction.
2237 ENUM
2238 BFD_RELOC_ARC_B26
2239 ENUMDOC
2240 ARC 26 bit absolute branch. The lowest two bits must be zero and are not
2241 stored in the instruction. The high 24 bits are installed in bits 23
2242 through 0.
2243
2244 COMMENT
2245 ENUM
2246 BFD_RELOC_D10V_10_PCREL_R
2247 ENUMDOC
2248 Mitsubishi D10V relocs.
2249 This is a 10-bit reloc with the right 2 bits
2250 assumed to be 0.
2251 ENUM
2252 BFD_RELOC_D10V_10_PCREL_L
2253 ENUMDOC
2254 Mitsubishi D10V relocs.
2255 This is a 10-bit reloc with the right 2 bits
2256 assumed to be 0. This is the same as the previous reloc
2257 except it is in the left container, i.e.,
2258 shifted left 15 bits.
2259 ENUM
2260 BFD_RELOC_D10V_18
2261 ENUMDOC
2262 This is an 18-bit reloc with the right 2 bits
2263 assumed to be 0.
2264 ENUM
2265 BFD_RELOC_D10V_18_PCREL
2266 ENUMDOC
2267 This is an 18-bit reloc with the right 2 bits
2268 assumed to be 0.
2269 COMMENT
2270
2271 COMMENT
2272 {* start-sanitize-d30v *}
2273 ENUM
2274 BFD_RELOC_D30V_6
2275 ENUMDOC
2276 Mitsubishi D30V relocs.
2277 This is a 6-bit absolute reloc.
2278 ENUM
2279 BFD_RELOC_D30V_9_PCREL
2280 ENUMDOC
2281 This is a 6-bit pc-relative reloc with
2282 the right 3 bits assumed to be 0.
2283 ENUM
2284 BFD_RELOC_D30V_9_PCREL_R
2285 ENUMDOC
2286 This is a 6-bit pc-relative reloc with
2287 the right 3 bits assumed to be 0. Same
2288 as the previous reloc but on the right side
2289 of the container.
2290 ENUM
2291 BFD_RELOC_D30V_15
2292 ENUMDOC
2293 This is a 12-bit absolute reloc with the
2294 right 3 bitsassumed to be 0.
2295 ENUM
2296 BFD_RELOC_D30V_15_PCREL
2297 ENUMDOC
2298 This is a 12-bit pc-relative reloc with
2299 the right 3 bits assumed to be 0.
2300 ENUM
2301 BFD_RELOC_D30V_15_PCREL_R
2302 ENUMDOC
2303 This is a 12-bit pc-relative reloc with
2304 the right 3 bits assumed to be 0. Same
2305 as the previous reloc but on the right side
2306 of the container.
2307 ENUM
2308 BFD_RELOC_D30V_21
2309 ENUMDOC
2310 This is an 18-bit absolute reloc with
2311 the right 3 bits assumed to be 0.
2312 ENUM
2313 BFD_RELOC_D30V_21_PCREL
2314 ENUMDOC
2315 This is an 18-bit pc-relative reloc with
2316 the right 3 bits assumed to be 0.
2317 ENUM
2318 BFD_RELOC_D30V_21_PCREL_R
2319 ENUMDOC
2320 This is an 18-bit pc-relative reloc with
2321 the right 3 bits assumed to be 0. Same
2322 as the previous reloc but on the right side
2323 of the container.
2324 ENUM
2325 BFD_RELOC_D30V_32
2326 ENUMDOC
2327 This is a 32-bit absolute reloc.
2328 ENUM
2329 BFD_RELOC_D30V_32_PCREL
2330 ENUMDOC
2331 This is a 32-bit pc-relative reloc.
2332 COMMENT
2333 {* end-sanitize-d30v *}
2334
2335 ENUM
2336 BFD_RELOC_M32R_24
2337 ENUMDOC
2338 Mitsubishi M32R relocs.
2339 This is a 24 bit absolute address.
2340 ENUM
2341 BFD_RELOC_M32R_10_PCREL
2342 ENUMDOC
2343 This is a 10-bit pc-relative reloc with the right 2 bits assumed to be 0.
2344 ENUM
2345 BFD_RELOC_M32R_18_PCREL
2346 ENUMDOC
2347 This is an 18-bit reloc with the right 2 bits assumed to be 0.
2348 ENUM
2349 BFD_RELOC_M32R_26_PCREL
2350 ENUMDOC
2351 This is a 26-bit reloc with the right 2 bits assumed to be 0.
2352 ENUM
2353 BFD_RELOC_M32R_HI16_ULO
2354 ENUMDOC
2355 This is a 16-bit reloc containing the high 16 bits of an address
2356 used when the lower 16 bits are treated as unsigned.
2357 ENUM
2358 BFD_RELOC_M32R_HI16_SLO
2359 ENUMDOC
2360 This is a 16-bit reloc containing the high 16 bits of an address
2361 used when the lower 16 bits are treated as signed.
2362 ENUM
2363 BFD_RELOC_M32R_LO16
2364 ENUMDOC
2365 This is a 16-bit reloc containing the lower 16 bits of an address.
2366 ENUM
2367 BFD_RELOC_M32R_SDA16
2368 ENUMDOC
2369 This is a 16-bit reloc containing the small data area offset for use in
2370 add3, load, and store instructions.
2371
2372 ENUM
2373 BFD_RELOC_V850_9_PCREL
2374 ENUMDOC
2375 This is a 9-bit reloc
2376 ENUM
2377 BFD_RELOC_V850_22_PCREL
2378 ENUMDOC
2379 This is a 22-bit reloc
2380
2381 ENUM
2382 BFD_RELOC_V850_SDA_16_16_OFFSET
2383 ENUMDOC
2384 This is a 16 bit offset from the short data area pointer.
2385 ENUM
2386 BFD_RELOC_V850_SDA_15_16_OFFSET
2387 ENUMDOC
2388 This is a 16 bit offset (of which only 15 bits are used) from the
2389 short data area pointer.
2390 ENUM
2391 BFD_RELOC_V850_ZDA_16_16_OFFSET
2392 ENUMDOC
2393 This is a 16 bit offset from the zero data area pointer.
2394 ENUM
2395 BFD_RELOC_V850_ZDA_15_16_OFFSET
2396 ENUMDOC
2397 This is a 16 bit offset (of which only 15 bits are used) from the
2398 zero data area pointer.
2399 ENUM
2400 BFD_RELOC_V850_TDA_6_8_OFFSET
2401 ENUMDOC
2402 This is an 8 bit offset (of which only 6 bits are used) from the
2403 tiny data area pointer.
2404 ENUM
2405 BFD_RELOC_V850_TDA_7_8_OFFSET
2406 ENUMDOC
2407 This is an 8bit offset (of which only 7 bits are used) from the tiny
2408 data area pointer.
2409 ENUM
2410 BFD_RELOC_V850_TDA_7_7_OFFSET
2411 ENUMDOC
2412 This is a 7 bit offset from the tiny data area pointer.
2413 ENUM
2414 BFD_RELOC_V850_TDA_16_16_OFFSET
2415 ENUMDOC
2416 This is a 16 bit offset from the tiny data area pointer.
2417 COMMENT
2418 {* start-sanitize-v850e *}
2419 ENUM
2420 BFD_RELOC_V850_TDA_4_5_OFFSET
2421 ENUMDOC
2422 This is a 5 bit offset (of which only 4 bits are used) from the tiny
2423 data area pointer.
2424 ENUM
2425 BFD_RELOC_V850_TDA_4_4_OFFSET
2426 ENUMDOC
2427 This is a 4 bit offset from the tiny data area pointer.
2428 ENUM
2429 BFD_RELOC_V850_SDA_16_16_SPLIT_OFFSET
2430 ENUMDOC
2431 This is a 16 bit offset from the short data area pointer, with the
2432 bits placed non-contigously in the instruction.
2433 ENUM
2434 BFD_RELOC_V850_ZDA_16_16_SPLIT_OFFSET
2435 ENUMDOC
2436 This is a 16 bit offset from the zero data area pointer, with the
2437 bits placed non-contigously in the instruction.
2438 ENUM
2439 BFD_RELOC_V850_CALLT_6_7_OFFSET
2440 ENUMDOC
2441 This is a 6 bit offset from the call table base pointer.
2442 ENUM
2443 BFD_RELOC_V850_CALLT_16_16_OFFSET
2444 ENUMDOC
2445 This is a 16 bit offset from the call table base pointer.
2446 COMMENT
2447 {* end-sanitize-v850e *}
2448
2449 ENUM
2450 BFD_RELOC_MN10300_32_PCREL
2451 ENUMDOC
2452 This is a 32bit pcrel reloc for the mn10300, offset by two bytes in the
2453 instruction.
2454 ENUM
2455 BFD_RELOC_MN10300_16_PCREL
2456 ENUMDOC
2457 This is a 16bit pcrel reloc for the mn10300, offset by two bytes in the
2458 instruction.
2459
2460 ENDSENUM
2461 BFD_RELOC_UNUSED
2462 CODE_FRAGMENT
2463 .
2464 .typedef enum bfd_reloc_code_real bfd_reloc_code_real_type;
2465 */
2466
2467
2468 /*
2469 FUNCTION
2470 bfd_reloc_type_lookup
2471
2472 SYNOPSIS
2473 reloc_howto_type *
2474 bfd_reloc_type_lookup (bfd *abfd, bfd_reloc_code_real_type code);
2475
2476 DESCRIPTION
2477 Return a pointer to a howto structure which, when
2478 invoked, will perform the relocation @var{code} on data from the
2479 architecture noted.
2480
2481 */
2482
2483
2484 reloc_howto_type *
2485 bfd_reloc_type_lookup (abfd, code)
2486 bfd *abfd;
2487 bfd_reloc_code_real_type code;
2488 {
2489 return BFD_SEND (abfd, reloc_type_lookup, (abfd, code));
2490 }
2491
2492 static reloc_howto_type bfd_howto_32 =
2493 HOWTO (0, 00, 2, 32, false, 0, complain_overflow_bitfield, 0, "VRT32", false, 0xffffffff, 0xffffffff, true);
2494
2495
2496 /*
2497 INTERNAL_FUNCTION
2498 bfd_default_reloc_type_lookup
2499
2500 SYNOPSIS
2501 reloc_howto_type *bfd_default_reloc_type_lookup
2502 (bfd *abfd, bfd_reloc_code_real_type code);
2503
2504 DESCRIPTION
2505 Provides a default relocation lookup routine for any architecture.
2506
2507
2508 */
2509
2510 reloc_howto_type *
2511 bfd_default_reloc_type_lookup (abfd, code)
2512 bfd *abfd;
2513 bfd_reloc_code_real_type code;
2514 {
2515 switch (code)
2516 {
2517 case BFD_RELOC_CTOR:
2518 /* The type of reloc used in a ctor, which will be as wide as the
2519 address - so either a 64, 32, or 16 bitter. */
2520 switch (bfd_get_arch_info (abfd)->bits_per_address)
2521 {
2522 case 64:
2523 BFD_FAIL ();
2524 case 32:
2525 return &bfd_howto_32;
2526 case 16:
2527 BFD_FAIL ();
2528 default:
2529 BFD_FAIL ();
2530 }
2531 default:
2532 BFD_FAIL ();
2533 }
2534 return (reloc_howto_type *) NULL;
2535 }
2536
2537 /*
2538 FUNCTION
2539 bfd_get_reloc_code_name
2540
2541 SYNOPSIS
2542 const char *bfd_get_reloc_code_name (bfd_reloc_code_real_type code);
2543
2544 DESCRIPTION
2545 Provides a printable name for the supplied relocation code.
2546 Useful mainly for printing error messages.
2547 */
2548
2549 const char *
2550 bfd_get_reloc_code_name (code)
2551 bfd_reloc_code_real_type code;
2552 {
2553 if (code > BFD_RELOC_UNUSED)
2554 return 0;
2555 return bfd_reloc_code_real_names[(int)code];
2556 }
2557
2558 /*
2559 INTERNAL_FUNCTION
2560 bfd_generic_relax_section
2561
2562 SYNOPSIS
2563 boolean bfd_generic_relax_section
2564 (bfd *abfd,
2565 asection *section,
2566 struct bfd_link_info *,
2567 boolean *);
2568
2569 DESCRIPTION
2570 Provides default handling for relaxing for back ends which
2571 don't do relaxing -- i.e., does nothing.
2572 */
2573
2574 /*ARGSUSED*/
2575 boolean
2576 bfd_generic_relax_section (abfd, section, link_info, again)
2577 bfd *abfd;
2578 asection *section;
2579 struct bfd_link_info *link_info;
2580 boolean *again;
2581 {
2582 *again = false;
2583 return true;
2584 }
2585
2586 /*
2587 INTERNAL_FUNCTION
2588 bfd_generic_get_relocated_section_contents
2589
2590 SYNOPSIS
2591 bfd_byte *
2592 bfd_generic_get_relocated_section_contents (bfd *abfd,
2593 struct bfd_link_info *link_info,
2594 struct bfd_link_order *link_order,
2595 bfd_byte *data,
2596 boolean relocateable,
2597 asymbol **symbols);
2598
2599 DESCRIPTION
2600 Provides default handling of relocation effort for back ends
2601 which can't be bothered to do it efficiently.
2602
2603 */
2604
2605 bfd_byte *
2606 bfd_generic_get_relocated_section_contents (abfd, link_info, link_order, data,
2607 relocateable, symbols)
2608 bfd *abfd;
2609 struct bfd_link_info *link_info;
2610 struct bfd_link_order *link_order;
2611 bfd_byte *data;
2612 boolean relocateable;
2613 asymbol **symbols;
2614 {
2615 /* Get enough memory to hold the stuff */
2616 bfd *input_bfd = link_order->u.indirect.section->owner;
2617 asection *input_section = link_order->u.indirect.section;
2618
2619 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
2620 arelent **reloc_vector = NULL;
2621 long reloc_count;
2622
2623 if (reloc_size < 0)
2624 goto error_return;
2625
2626 reloc_vector = (arelent **) bfd_malloc ((size_t) reloc_size);
2627 if (reloc_vector == NULL && reloc_size != 0)
2628 goto error_return;
2629
2630 /* read in the section */
2631 if (!bfd_get_section_contents (input_bfd,
2632 input_section,
2633 (PTR) data,
2634 0,
2635 input_section->_raw_size))
2636 goto error_return;
2637
2638 /* We're not relaxing the section, so just copy the size info */
2639 input_section->_cooked_size = input_section->_raw_size;
2640 input_section->reloc_done = true;
2641
2642 reloc_count = bfd_canonicalize_reloc (input_bfd,
2643 input_section,
2644 reloc_vector,
2645 symbols);
2646 if (reloc_count < 0)
2647 goto error_return;
2648
2649 if (reloc_count > 0)
2650 {
2651 arelent **parent;
2652 for (parent = reloc_vector; *parent != (arelent *) NULL;
2653 parent++)
2654 {
2655 char *error_message = (char *) NULL;
2656 bfd_reloc_status_type r =
2657 bfd_perform_relocation (input_bfd,
2658 *parent,
2659 (PTR) data,
2660 input_section,
2661 relocateable ? abfd : (bfd *) NULL,
2662 &error_message);
2663
2664 if (relocateable)
2665 {
2666 asection *os = input_section->output_section;
2667
2668 /* A partial link, so keep the relocs */
2669 os->orelocation[os->reloc_count] = *parent;
2670 os->reloc_count++;
2671 }
2672
2673 if (r != bfd_reloc_ok)
2674 {
2675 switch (r)
2676 {
2677 case bfd_reloc_undefined:
2678 if (!((*link_info->callbacks->undefined_symbol)
2679 (link_info, bfd_asymbol_name (*(*parent)->sym_ptr_ptr),
2680 input_bfd, input_section, (*parent)->address)))
2681 goto error_return;
2682 break;
2683 case bfd_reloc_dangerous:
2684 BFD_ASSERT (error_message != (char *) NULL);
2685 if (!((*link_info->callbacks->reloc_dangerous)
2686 (link_info, error_message, input_bfd, input_section,
2687 (*parent)->address)))
2688 goto error_return;
2689 break;
2690 case bfd_reloc_overflow:
2691 if (!((*link_info->callbacks->reloc_overflow)
2692 (link_info, bfd_asymbol_name (*(*parent)->sym_ptr_ptr),
2693 (*parent)->howto->name, (*parent)->addend,
2694 input_bfd, input_section, (*parent)->address)))
2695 goto error_return;
2696 break;
2697 case bfd_reloc_outofrange:
2698 default:
2699 abort ();
2700 break;
2701 }
2702
2703 }
2704 }
2705 }
2706 if (reloc_vector != NULL)
2707 free (reloc_vector);
2708 return data;
2709
2710 error_return:
2711 if (reloc_vector != NULL)
2712 free (reloc_vector);
2713 return NULL;
2714 }