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* reloc.c (struct reloc_howto_struct): Fix typo in comment.
[thirdparty/binutils-gdb.git] / bfd / reloc.c
1 /* BFD support for handling relocation entries.
2 Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 1997
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 /*
456 FUNCTION
457 bfd_perform_relocation
458
459 SYNOPSIS
460 bfd_reloc_status_type
461 bfd_perform_relocation
462 (bfd *abfd,
463 arelent *reloc_entry,
464 PTR data,
465 asection *input_section,
466 bfd *output_bfd,
467 char **error_message);
468
469 DESCRIPTION
470 If @var{output_bfd} is supplied to this function, the
471 generated image will be relocatable; the relocations are
472 copied to the output file after they have been changed to
473 reflect the new state of the world. There are two ways of
474 reflecting the results of partial linkage in an output file:
475 by modifying the output data in place, and by modifying the
476 relocation record. Some native formats (e.g., basic a.out and
477 basic coff) have no way of specifying an addend in the
478 relocation type, so the addend has to go in the output data.
479 This is no big deal since in these formats the output data
480 slot will always be big enough for the addend. Complex reloc
481 types with addends were invented to solve just this problem.
482 The @var{error_message} argument is set to an error message if
483 this return @code{bfd_reloc_dangerous}.
484
485 */
486
487
488 bfd_reloc_status_type
489 bfd_perform_relocation (abfd, reloc_entry, data, input_section, output_bfd,
490 error_message)
491 bfd *abfd;
492 arelent *reloc_entry;
493 PTR data;
494 asection *input_section;
495 bfd *output_bfd;
496 char **error_message;
497 {
498 bfd_vma relocation;
499 bfd_reloc_status_type flag = bfd_reloc_ok;
500 bfd_size_type addr = reloc_entry->address;
501 bfd_vma output_base = 0;
502 reloc_howto_type *howto = reloc_entry->howto;
503 asection *reloc_target_output_section;
504 asymbol *symbol;
505
506 symbol = *(reloc_entry->sym_ptr_ptr);
507 if (bfd_is_abs_section (symbol->section)
508 && output_bfd != (bfd *) NULL)
509 {
510 reloc_entry->address += input_section->output_offset;
511 return bfd_reloc_ok;
512 }
513
514 /* If we are not producing relocateable output, return an error if
515 the symbol is not defined. An undefined weak symbol is
516 considered to have a value of zero (SVR4 ABI, p. 4-27). */
517 if (bfd_is_und_section (symbol->section)
518 && (symbol->flags & BSF_WEAK) == 0
519 && output_bfd == (bfd *) NULL)
520 flag = bfd_reloc_undefined;
521
522 /* If there is a function supplied to handle this relocation type,
523 call it. It'll return `bfd_reloc_continue' if further processing
524 can be done. */
525 if (howto->special_function)
526 {
527 bfd_reloc_status_type cont;
528 cont = howto->special_function (abfd, reloc_entry, symbol, data,
529 input_section, output_bfd,
530 error_message);
531 if (cont != bfd_reloc_continue)
532 return cont;
533 }
534
535 /* Is the address of the relocation really within the section? */
536 if (reloc_entry->address > input_section->_cooked_size)
537 return bfd_reloc_outofrange;
538
539 /* Work out which section the relocation is targetted at and the
540 initial relocation command value. */
541
542 /* Get symbol value. (Common symbols are special.) */
543 if (bfd_is_com_section (symbol->section))
544 relocation = 0;
545 else
546 relocation = symbol->value;
547
548
549 reloc_target_output_section = symbol->section->output_section;
550
551 /* Convert input-section-relative symbol value to absolute. */
552 if (output_bfd && howto->partial_inplace == false)
553 output_base = 0;
554 else
555 output_base = reloc_target_output_section->vma;
556
557 relocation += output_base + symbol->section->output_offset;
558
559 /* Add in supplied addend. */
560 relocation += reloc_entry->addend;
561
562 /* Here the variable relocation holds the final address of the
563 symbol we are relocating against, plus any addend. */
564
565 if (howto->pc_relative == true)
566 {
567 /* This is a PC relative relocation. We want to set RELOCATION
568 to the distance between the address of the symbol and the
569 location. RELOCATION is already the address of the symbol.
570
571 We start by subtracting the address of the section containing
572 the location.
573
574 If pcrel_offset is set, we must further subtract the position
575 of the location within the section. Some targets arrange for
576 the addend to be the negative of the position of the location
577 within the section; for example, i386-aout does this. For
578 i386-aout, pcrel_offset is false. Some other targets do not
579 include the position of the location; for example, m88kbcs,
580 or ELF. For those targets, pcrel_offset is true.
581
582 If we are producing relocateable output, then we must ensure
583 that this reloc will be correctly computed when the final
584 relocation is done. If pcrel_offset is false we want to wind
585 up with the negative of the location within the section,
586 which means we must adjust the existing addend by the change
587 in the location within the section. If pcrel_offset is true
588 we do not want to adjust the existing addend at all.
589
590 FIXME: This seems logical to me, but for the case of
591 producing relocateable output it is not what the code
592 actually does. I don't want to change it, because it seems
593 far too likely that something will break. */
594
595 relocation -=
596 input_section->output_section->vma + input_section->output_offset;
597
598 if (howto->pcrel_offset == true)
599 relocation -= reloc_entry->address;
600 }
601
602 if (output_bfd != (bfd *) NULL)
603 {
604 if (howto->partial_inplace == false)
605 {
606 /* This is a partial relocation, and we want to apply the relocation
607 to the reloc entry rather than the raw data. Modify the reloc
608 inplace to reflect what we now know. */
609 reloc_entry->addend = relocation;
610 reloc_entry->address += input_section->output_offset;
611 return flag;
612 }
613 else
614 {
615 /* This is a partial relocation, but inplace, so modify the
616 reloc record a bit.
617
618 If we've relocated with a symbol with a section, change
619 into a ref to the section belonging to the symbol. */
620
621 reloc_entry->address += input_section->output_offset;
622
623 /* WTF?? */
624 if (abfd->xvec->flavour == bfd_target_coff_flavour
625 && strcmp (abfd->xvec->name, "aixcoff-rs6000") != 0
626 && strcmp (abfd->xvec->name, "xcoff-powermac") != 0
627 && strcmp (abfd->xvec->name, "coff-Intel-little") != 0
628 && strcmp (abfd->xvec->name, "coff-Intel-big") != 0)
629 {
630 #if 1
631 /* For m68k-coff, the addend was being subtracted twice during
632 relocation with -r. Removing the line below this comment
633 fixes that problem; see PR 2953.
634
635 However, Ian wrote the following, regarding removing the line below,
636 which explains why it is still enabled: --djm
637
638 If you put a patch like that into BFD you need to check all the COFF
639 linkers. I am fairly certain that patch will break coff-i386 (e.g.,
640 SCO); see coff_i386_reloc in coff-i386.c where I worked around the
641 problem in a different way. There may very well be a reason that the
642 code works as it does.
643
644 Hmmm. The first obvious point is that bfd_perform_relocation should
645 not have any tests that depend upon the flavour. It's seem like
646 entirely the wrong place for such a thing. The second obvious point
647 is that the current code ignores the reloc addend when producing
648 relocateable output for COFF. That's peculiar. In fact, I really
649 have no idea what the point of the line you want to remove is.
650
651 A typical COFF reloc subtracts the old value of the symbol and adds in
652 the new value to the location in the object file (if it's a pc
653 relative reloc it adds the difference between the symbol value and the
654 location). When relocating we need to preserve that property.
655
656 BFD handles this by setting the addend to the negative of the old
657 value of the symbol. Unfortunately it handles common symbols in a
658 non-standard way (it doesn't subtract the old value) but that's a
659 different story (we can't change it without losing backward
660 compatibility with old object files) (coff-i386 does subtract the old
661 value, to be compatible with existing coff-i386 targets, like SCO).
662
663 So everything works fine when not producing relocateable output. When
664 we are producing relocateable output, logically we should do exactly
665 what we do when not producing relocateable output. Therefore, your
666 patch is correct. In fact, it should probably always just set
667 reloc_entry->addend to 0 for all cases, since it is, in fact, going to
668 add the value into the object file. This won't hurt the COFF code,
669 which doesn't use the addend; I'm not sure what it will do to other
670 formats (the thing to check for would be whether any formats both use
671 the addend and set partial_inplace).
672
673 When I wanted to make coff-i386 produce relocateable output, I ran
674 into the problem that you are running into: I wanted to remove that
675 line. Rather than risk it, I made the coff-i386 relocs use a special
676 function; it's coff_i386_reloc in coff-i386.c. The function
677 specifically adds the addend field into the object file, knowing that
678 bfd_perform_relocation is not going to. If you remove that line, then
679 coff-i386.c will wind up adding the addend field in twice. It's
680 trivial to fix; it just needs to be done.
681
682 The problem with removing the line is just that it may break some
683 working code. With BFD it's hard to be sure of anything. The right
684 way to deal with this is simply to build and test at least all the
685 supported COFF targets. It should be straightforward if time and disk
686 space consuming. For each target:
687 1) build the linker
688 2) generate some executable, and link it using -r (I would
689 probably use paranoia.o and link against newlib/libc.a, which
690 for all the supported targets would be available in
691 /usr/cygnus/progressive/H-host/target/lib/libc.a).
692 3) make the change to reloc.c
693 4) rebuild the linker
694 5) repeat step 2
695 6) if the resulting object files are the same, you have at least
696 made it no worse
697 7) if they are different you have to figure out which version is
698 right
699 */
700 relocation -= reloc_entry->addend;
701 #endif
702 reloc_entry->addend = 0;
703 }
704 else
705 {
706 reloc_entry->addend = relocation;
707 }
708 }
709 }
710 else
711 {
712 reloc_entry->addend = 0;
713 }
714
715 /* FIXME: This overflow checking is incomplete, because the value
716 might have overflowed before we get here. For a correct check we
717 need to compute the value in a size larger than bitsize, but we
718 can't reasonably do that for a reloc the same size as a host
719 machine word.
720 FIXME: We should also do overflow checking on the result after
721 adding in the value contained in the object file. */
722 if (howto->complain_on_overflow != complain_overflow_dont
723 && flag == bfd_reloc_ok)
724 {
725 bfd_vma check;
726
727 /* Get the value that will be used for the relocation, but
728 starting at bit position zero. */
729 check = relocation >> howto->rightshift;
730 switch (howto->complain_on_overflow)
731 {
732 case complain_overflow_signed:
733 {
734 /* Assumes two's complement. */
735 bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
736 bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
737
738 /* The above right shift is incorrect for a signed value.
739 Fix it up by forcing on the upper bits. */
740 if (howto->rightshift > 0
741 && (bfd_signed_vma) relocation < 0)
742 check |= ((bfd_vma) - 1
743 & ~((bfd_vma) - 1
744 >> howto->rightshift));
745 if ((bfd_signed_vma) check > reloc_signed_max
746 || (bfd_signed_vma) check < reloc_signed_min)
747 flag = bfd_reloc_overflow;
748 }
749 break;
750 case complain_overflow_unsigned:
751 {
752 /* Assumes two's complement. This expression avoids
753 overflow if howto->bitsize is the number of bits in
754 bfd_vma. */
755 bfd_vma reloc_unsigned_max =
756 (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
757
758 if ((bfd_vma) check > reloc_unsigned_max)
759 flag = bfd_reloc_overflow;
760 }
761 break;
762 case complain_overflow_bitfield:
763 {
764 /* Assumes two's complement. This expression avoids
765 overflow if howto->bitsize is the number of bits in
766 bfd_vma. */
767 bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
768
769 if (((bfd_vma) check & ~reloc_bits) != 0
770 && ((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
771 {
772 /* The above right shift is incorrect for a signed
773 value. See if turning on the upper bits fixes the
774 overflow. */
775 if (howto->rightshift > 0
776 && (bfd_signed_vma) relocation < 0)
777 {
778 check |= ((bfd_vma) - 1
779 & ~((bfd_vma) - 1
780 >> howto->rightshift));
781 if (((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
782 flag = bfd_reloc_overflow;
783 }
784 else
785 flag = bfd_reloc_overflow;
786 }
787 }
788 break;
789 default:
790 abort ();
791 }
792 }
793
794 /*
795 Either we are relocating all the way, or we don't want to apply
796 the relocation to the reloc entry (probably because there isn't
797 any room in the output format to describe addends to relocs)
798 */
799
800 /* The cast to bfd_vma avoids a bug in the Alpha OSF/1 C compiler
801 (OSF version 1.3, compiler version 3.11). It miscompiles the
802 following program:
803
804 struct str
805 {
806 unsigned int i0;
807 } s = { 0 };
808
809 int
810 main ()
811 {
812 unsigned long x;
813
814 x = 0x100000000;
815 x <<= (unsigned long) s.i0;
816 if (x == 0)
817 printf ("failed\n");
818 else
819 printf ("succeeded (%lx)\n", x);
820 }
821 */
822
823 relocation >>= (bfd_vma) howto->rightshift;
824
825 /* Shift everything up to where it's going to be used */
826
827 relocation <<= (bfd_vma) howto->bitpos;
828
829 /* Wait for the day when all have the mask in them */
830
831 /* What we do:
832 i instruction to be left alone
833 o offset within instruction
834 r relocation offset to apply
835 S src mask
836 D dst mask
837 N ~dst mask
838 A part 1
839 B part 2
840 R result
841
842 Do this:
843 i i i i i o o o o o from bfd_get<size>
844 and S S S S S to get the size offset we want
845 + r r r r r r r r r r to get the final value to place
846 and D D D D D to chop to right size
847 -----------------------
848 A A A A A
849 And this:
850 ... i i i i i o o o o o from bfd_get<size>
851 and N N N N N get instruction
852 -----------------------
853 ... B B B B B
854
855 And then:
856 B B B B B
857 or A A A A A
858 -----------------------
859 R R R R R R R R R R put into bfd_put<size>
860 */
861
862 #define DOIT(x) \
863 x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) + relocation) & howto->dst_mask))
864
865 switch (howto->size)
866 {
867 case 0:
868 {
869 char x = bfd_get_8 (abfd, (char *) data + addr);
870 DOIT (x);
871 bfd_put_8 (abfd, x, (unsigned char *) data + addr);
872 }
873 break;
874
875 case 1:
876 {
877 short x = bfd_get_16 (abfd, (bfd_byte *) data + addr);
878 DOIT (x);
879 bfd_put_16 (abfd, x, (unsigned char *) data + addr);
880 }
881 break;
882 case 2:
883 {
884 long x = bfd_get_32 (abfd, (bfd_byte *) data + addr);
885 DOIT (x);
886 bfd_put_32 (abfd, x, (bfd_byte *) data + addr);
887 }
888 break;
889 case -2:
890 {
891 long x = bfd_get_32 (abfd, (bfd_byte *) data + addr);
892 relocation = -relocation;
893 DOIT (x);
894 bfd_put_32 (abfd, x, (bfd_byte *) data + addr);
895 }
896 break;
897
898 case -1:
899 {
900 long x = bfd_get_16 (abfd, (bfd_byte *) data + addr);
901 relocation = -relocation;
902 DOIT (x);
903 bfd_put_16 (abfd, x, (bfd_byte *) data + addr);
904 }
905 break;
906
907 case 3:
908 /* Do nothing */
909 break;
910
911 case 4:
912 #ifdef BFD64
913 {
914 bfd_vma x = bfd_get_64 (abfd, (bfd_byte *) data + addr);
915 DOIT (x);
916 bfd_put_64 (abfd, x, (bfd_byte *) data + addr);
917 }
918 #else
919 abort ();
920 #endif
921 break;
922 default:
923 return bfd_reloc_other;
924 }
925
926 return flag;
927 }
928
929 /*
930 FUNCTION
931 bfd_install_relocation
932
933 SYNOPSIS
934 bfd_reloc_status_type
935 bfd_install_relocation
936 (bfd *abfd,
937 arelent *reloc_entry,
938 PTR data, bfd_vma data_start,
939 asection *input_section,
940 char **error_message);
941
942 DESCRIPTION
943 This looks remarkably like <<bfd_perform_relocation>>, except it
944 does not expect that the section contents have been filled in.
945 I.e., it's suitable for use when creating, rather than applying
946 a relocation.
947
948 For now, this function should be considered reserved for the
949 assembler.
950
951 */
952
953
954 bfd_reloc_status_type
955 bfd_install_relocation (abfd, reloc_entry, data_start, data_start_offset,
956 input_section, error_message)
957 bfd *abfd;
958 arelent *reloc_entry;
959 PTR data_start;
960 bfd_vma data_start_offset;
961 asection *input_section;
962 char **error_message;
963 {
964 bfd_vma relocation;
965 bfd_reloc_status_type flag = bfd_reloc_ok;
966 bfd_size_type addr = reloc_entry->address;
967 bfd_vma output_base = 0;
968 reloc_howto_type *howto = reloc_entry->howto;
969 asection *reloc_target_output_section;
970 asymbol *symbol;
971 bfd_byte *data;
972
973 symbol = *(reloc_entry->sym_ptr_ptr);
974 if (bfd_is_abs_section (symbol->section))
975 {
976 reloc_entry->address += input_section->output_offset;
977 return bfd_reloc_ok;
978 }
979
980 /* If there is a function supplied to handle this relocation type,
981 call it. It'll return `bfd_reloc_continue' if further processing
982 can be done. */
983 if (howto->special_function)
984 {
985 bfd_reloc_status_type cont;
986 /* XXX - The special_function calls haven't been fixed up to deal
987 with creating new relocations and section contents. */
988 cont = howto->special_function (abfd, reloc_entry, symbol,
989 /* XXX - Non-portable! */
990 ((bfd_byte *) data_start
991 - data_start_offset),
992 input_section, abfd, error_message);
993 if (cont != bfd_reloc_continue)
994 return cont;
995 }
996
997 /* Is the address of the relocation really within the section? */
998 if (reloc_entry->address > input_section->_cooked_size)
999 return bfd_reloc_outofrange;
1000
1001 /* Work out which section the relocation is targetted at and the
1002 initial relocation command value. */
1003
1004 /* Get symbol value. (Common symbols are special.) */
1005 if (bfd_is_com_section (symbol->section))
1006 relocation = 0;
1007 else
1008 relocation = symbol->value;
1009
1010
1011 reloc_target_output_section = symbol->section->output_section;
1012
1013 /* Convert input-section-relative symbol value to absolute. */
1014 if (howto->partial_inplace == false)
1015 output_base = 0;
1016 else
1017 output_base = reloc_target_output_section->vma;
1018
1019 relocation += output_base + symbol->section->output_offset;
1020
1021 /* Add in supplied addend. */
1022 relocation += reloc_entry->addend;
1023
1024 /* Here the variable relocation holds the final address of the
1025 symbol we are relocating against, plus any addend. */
1026
1027 if (howto->pc_relative == true)
1028 {
1029 /* This is a PC relative relocation. We want to set RELOCATION
1030 to the distance between the address of the symbol and the
1031 location. RELOCATION is already the address of the symbol.
1032
1033 We start by subtracting the address of the section containing
1034 the location.
1035
1036 If pcrel_offset is set, we must further subtract the position
1037 of the location within the section. Some targets arrange for
1038 the addend to be the negative of the position of the location
1039 within the section; for example, i386-aout does this. For
1040 i386-aout, pcrel_offset is false. Some other targets do not
1041 include the position of the location; for example, m88kbcs,
1042 or ELF. For those targets, pcrel_offset is true.
1043
1044 If we are producing relocateable output, then we must ensure
1045 that this reloc will be correctly computed when the final
1046 relocation is done. If pcrel_offset is false we want to wind
1047 up with the negative of the location within the section,
1048 which means we must adjust the existing addend by the change
1049 in the location within the section. If pcrel_offset is true
1050 we do not want to adjust the existing addend at all.
1051
1052 FIXME: This seems logical to me, but for the case of
1053 producing relocateable output it is not what the code
1054 actually does. I don't want to change it, because it seems
1055 far too likely that something will break. */
1056
1057 relocation -=
1058 input_section->output_section->vma + input_section->output_offset;
1059
1060 if (howto->pcrel_offset == true && howto->partial_inplace == true)
1061 relocation -= reloc_entry->address;
1062 }
1063
1064 if (howto->partial_inplace == false)
1065 {
1066 /* This is a partial relocation, and we want to apply the relocation
1067 to the reloc entry rather than the raw data. Modify the reloc
1068 inplace to reflect what we now know. */
1069 reloc_entry->addend = relocation;
1070 reloc_entry->address += input_section->output_offset;
1071 return flag;
1072 }
1073 else
1074 {
1075 /* This is a partial relocation, but inplace, so modify the
1076 reloc record a bit.
1077
1078 If we've relocated with a symbol with a section, change
1079 into a ref to the section belonging to the symbol. */
1080
1081 reloc_entry->address += input_section->output_offset;
1082
1083 /* WTF?? */
1084 if (abfd->xvec->flavour == bfd_target_coff_flavour
1085 && strcmp (abfd->xvec->name, "aixcoff-rs6000") != 0
1086 && strcmp (abfd->xvec->name, "xcoff-powermac") != 0
1087 && strcmp (abfd->xvec->name, "coff-Intel-little") != 0
1088 && strcmp (abfd->xvec->name, "coff-Intel-big") != 0)
1089 {
1090 #if 1
1091 /* For m68k-coff, the addend was being subtracted twice during
1092 relocation with -r. Removing the line below this comment
1093 fixes that problem; see PR 2953.
1094
1095 However, Ian wrote the following, regarding removing the line below,
1096 which explains why it is still enabled: --djm
1097
1098 If you put a patch like that into BFD you need to check all the COFF
1099 linkers. I am fairly certain that patch will break coff-i386 (e.g.,
1100 SCO); see coff_i386_reloc in coff-i386.c where I worked around the
1101 problem in a different way. There may very well be a reason that the
1102 code works as it does.
1103
1104 Hmmm. The first obvious point is that bfd_install_relocation should
1105 not have any tests that depend upon the flavour. It's seem like
1106 entirely the wrong place for such a thing. The second obvious point
1107 is that the current code ignores the reloc addend when producing
1108 relocateable output for COFF. That's peculiar. In fact, I really
1109 have no idea what the point of the line you want to remove is.
1110
1111 A typical COFF reloc subtracts the old value of the symbol and adds in
1112 the new value to the location in the object file (if it's a pc
1113 relative reloc it adds the difference between the symbol value and the
1114 location). When relocating we need to preserve that property.
1115
1116 BFD handles this by setting the addend to the negative of the old
1117 value of the symbol. Unfortunately it handles common symbols in a
1118 non-standard way (it doesn't subtract the old value) but that's a
1119 different story (we can't change it without losing backward
1120 compatibility with old object files) (coff-i386 does subtract the old
1121 value, to be compatible with existing coff-i386 targets, like SCO).
1122
1123 So everything works fine when not producing relocateable output. When
1124 we are producing relocateable output, logically we should do exactly
1125 what we do when not producing relocateable output. Therefore, your
1126 patch is correct. In fact, it should probably always just set
1127 reloc_entry->addend to 0 for all cases, since it is, in fact, going to
1128 add the value into the object file. This won't hurt the COFF code,
1129 which doesn't use the addend; I'm not sure what it will do to other
1130 formats (the thing to check for would be whether any formats both use
1131 the addend and set partial_inplace).
1132
1133 When I wanted to make coff-i386 produce relocateable output, I ran
1134 into the problem that you are running into: I wanted to remove that
1135 line. Rather than risk it, I made the coff-i386 relocs use a special
1136 function; it's coff_i386_reloc in coff-i386.c. The function
1137 specifically adds the addend field into the object file, knowing that
1138 bfd_install_relocation is not going to. If you remove that line, then
1139 coff-i386.c will wind up adding the addend field in twice. It's
1140 trivial to fix; it just needs to be done.
1141
1142 The problem with removing the line is just that it may break some
1143 working code. With BFD it's hard to be sure of anything. The right
1144 way to deal with this is simply to build and test at least all the
1145 supported COFF targets. It should be straightforward if time and disk
1146 space consuming. For each target:
1147 1) build the linker
1148 2) generate some executable, and link it using -r (I would
1149 probably use paranoia.o and link against newlib/libc.a, which
1150 for all the supported targets would be available in
1151 /usr/cygnus/progressive/H-host/target/lib/libc.a).
1152 3) make the change to reloc.c
1153 4) rebuild the linker
1154 5) repeat step 2
1155 6) if the resulting object files are the same, you have at least
1156 made it no worse
1157 7) if they are different you have to figure out which version is
1158 right
1159 */
1160 relocation -= reloc_entry->addend;
1161 #endif
1162 reloc_entry->addend = 0;
1163 }
1164 else
1165 {
1166 reloc_entry->addend = relocation;
1167 }
1168 }
1169
1170 /* FIXME: This overflow checking is incomplete, because the value
1171 might have overflowed before we get here. For a correct check we
1172 need to compute the value in a size larger than bitsize, but we
1173 can't reasonably do that for a reloc the same size as a host
1174 machine word.
1175
1176 FIXME: We should also do overflow checking on the result after
1177 adding in the value contained in the object file. */
1178 if (howto->complain_on_overflow != complain_overflow_dont)
1179 {
1180 bfd_vma check;
1181
1182 /* Get the value that will be used for the relocation, but
1183 starting at bit position zero. */
1184 check = relocation >> howto->rightshift;
1185 switch (howto->complain_on_overflow)
1186 {
1187 case complain_overflow_signed:
1188 {
1189 /* Assumes two's complement. */
1190 bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
1191 bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
1192
1193 /* The above right shift is incorrect for a signed value.
1194 Fix it up by forcing on the upper bits. */
1195 if (howto->rightshift > 0
1196 && (bfd_signed_vma) relocation < 0)
1197 check |= ((bfd_vma) - 1
1198 & ~((bfd_vma) - 1
1199 >> howto->rightshift));
1200 if ((bfd_signed_vma) check > reloc_signed_max
1201 || (bfd_signed_vma) check < reloc_signed_min)
1202 flag = bfd_reloc_overflow;
1203 }
1204 break;
1205 case complain_overflow_unsigned:
1206 {
1207 /* Assumes two's complement. This expression avoids
1208 overflow if howto->bitsize is the number of bits in
1209 bfd_vma. */
1210 bfd_vma reloc_unsigned_max =
1211 (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1212
1213 if ((bfd_vma) check > reloc_unsigned_max)
1214 flag = bfd_reloc_overflow;
1215 }
1216 break;
1217 case complain_overflow_bitfield:
1218 {
1219 /* Assumes two's complement. This expression avoids
1220 overflow if howto->bitsize is the number of bits in
1221 bfd_vma. */
1222 bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1223
1224 if (((bfd_vma) check & ~reloc_bits) != 0
1225 && ((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
1226 {
1227 /* The above right shift is incorrect for a signed
1228 value. See if turning on the upper bits fixes the
1229 overflow. */
1230 if (howto->rightshift > 0
1231 && (bfd_signed_vma) relocation < 0)
1232 {
1233 check |= ((bfd_vma) - 1
1234 & ~((bfd_vma) - 1
1235 >> howto->rightshift));
1236 if (((bfd_vma) check & ~reloc_bits) != (-1 & ~reloc_bits))
1237 flag = bfd_reloc_overflow;
1238 }
1239 else
1240 flag = bfd_reloc_overflow;
1241 }
1242 }
1243 break;
1244 default:
1245 abort ();
1246 }
1247 }
1248
1249 /*
1250 Either we are relocating all the way, or we don't want to apply
1251 the relocation to the reloc entry (probably because there isn't
1252 any room in the output format to describe addends to relocs)
1253 */
1254
1255 /* The cast to bfd_vma avoids a bug in the Alpha OSF/1 C compiler
1256 (OSF version 1.3, compiler version 3.11). It miscompiles the
1257 following program:
1258
1259 struct str
1260 {
1261 unsigned int i0;
1262 } s = { 0 };
1263
1264 int
1265 main ()
1266 {
1267 unsigned long x;
1268
1269 x = 0x100000000;
1270 x <<= (unsigned long) s.i0;
1271 if (x == 0)
1272 printf ("failed\n");
1273 else
1274 printf ("succeeded (%lx)\n", x);
1275 }
1276 */
1277
1278 relocation >>= (bfd_vma) howto->rightshift;
1279
1280 /* Shift everything up to where it's going to be used */
1281
1282 relocation <<= (bfd_vma) howto->bitpos;
1283
1284 /* Wait for the day when all have the mask in them */
1285
1286 /* What we do:
1287 i instruction to be left alone
1288 o offset within instruction
1289 r relocation offset to apply
1290 S src mask
1291 D dst mask
1292 N ~dst mask
1293 A part 1
1294 B part 2
1295 R result
1296
1297 Do this:
1298 i i i i i o o o o o from bfd_get<size>
1299 and S S S S S to get the size offset we want
1300 + r r r r r r r r r r to get the final value to place
1301 and D D D D D to chop to right size
1302 -----------------------
1303 A A A A A
1304 And this:
1305 ... i i i i i o o o o o from bfd_get<size>
1306 and N N N N N get instruction
1307 -----------------------
1308 ... B B B B B
1309
1310 And then:
1311 B B B B B
1312 or A A A A A
1313 -----------------------
1314 R R R R R R R R R R put into bfd_put<size>
1315 */
1316
1317 #define DOIT(x) \
1318 x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) + relocation) & howto->dst_mask))
1319
1320 data = (bfd_byte *) data_start + (addr - data_start_offset);
1321
1322 switch (howto->size)
1323 {
1324 case 0:
1325 {
1326 char x = bfd_get_8 (abfd, (char *) data);
1327 DOIT (x);
1328 bfd_put_8 (abfd, x, (unsigned char *) data);
1329 }
1330 break;
1331
1332 case 1:
1333 {
1334 short x = bfd_get_16 (abfd, (bfd_byte *) data);
1335 DOIT (x);
1336 bfd_put_16 (abfd, x, (unsigned char *) data);
1337 }
1338 break;
1339 case 2:
1340 {
1341 long x = bfd_get_32 (abfd, (bfd_byte *) data);
1342 DOIT (x);
1343 bfd_put_32 (abfd, x, (bfd_byte *) data);
1344 }
1345 break;
1346 case -2:
1347 {
1348 long x = bfd_get_32 (abfd, (bfd_byte *) data);
1349 relocation = -relocation;
1350 DOIT (x);
1351 bfd_put_32 (abfd, x, (bfd_byte *) data);
1352 }
1353 break;
1354
1355 case 3:
1356 /* Do nothing */
1357 break;
1358
1359 case 4:
1360 {
1361 bfd_vma x = bfd_get_64 (abfd, (bfd_byte *) data);
1362 DOIT (x);
1363 bfd_put_64 (abfd, x, (bfd_byte *) data);
1364 }
1365 break;
1366 default:
1367 return bfd_reloc_other;
1368 }
1369
1370 return flag;
1371 }
1372
1373 /* This relocation routine is used by some of the backend linkers.
1374 They do not construct asymbol or arelent structures, so there is no
1375 reason for them to use bfd_perform_relocation. Also,
1376 bfd_perform_relocation is so hacked up it is easier to write a new
1377 function than to try to deal with it.
1378
1379 This routine does a final relocation. It should not be used when
1380 generating relocateable output.
1381
1382 FIXME: This routine ignores any special_function in the HOWTO,
1383 since the existing special_function values have been written for
1384 bfd_perform_relocation.
1385
1386 HOWTO is the reloc howto information.
1387 INPUT_BFD is the BFD which the reloc applies to.
1388 INPUT_SECTION is the section which the reloc applies to.
1389 CONTENTS is the contents of the section.
1390 ADDRESS is the address of the reloc within INPUT_SECTION.
1391 VALUE is the value of the symbol the reloc refers to.
1392 ADDEND is the addend of the reloc. */
1393
1394 bfd_reloc_status_type
1395 _bfd_final_link_relocate (howto, input_bfd, input_section, contents, address,
1396 value, addend)
1397 reloc_howto_type *howto;
1398 bfd *input_bfd;
1399 asection *input_section;
1400 bfd_byte *contents;
1401 bfd_vma address;
1402 bfd_vma value;
1403 bfd_vma addend;
1404 {
1405 bfd_vma relocation;
1406
1407 /* Sanity check the address. */
1408 if (address > input_section->_raw_size)
1409 return bfd_reloc_outofrange;
1410
1411 /* This function assumes that we are dealing with a basic relocation
1412 against a symbol. We want to compute the value of the symbol to
1413 relocate to. This is just VALUE, the value of the symbol, plus
1414 ADDEND, any addend associated with the reloc. */
1415 relocation = value + addend;
1416
1417 /* If the relocation is PC relative, we want to set RELOCATION to
1418 the distance between the symbol (currently in RELOCATION) and the
1419 location we are relocating. Some targets (e.g., i386-aout)
1420 arrange for the contents of the section to be the negative of the
1421 offset of the location within the section; for such targets
1422 pcrel_offset is false. Other targets (e.g., m88kbcs or ELF)
1423 simply leave the contents of the section as zero; for such
1424 targets pcrel_offset is true. If pcrel_offset is false we do not
1425 need to subtract out the offset of the location within the
1426 section (which is just ADDRESS). */
1427 if (howto->pc_relative)
1428 {
1429 relocation -= (input_section->output_section->vma
1430 + input_section->output_offset);
1431 if (howto->pcrel_offset)
1432 relocation -= address;
1433 }
1434
1435 return _bfd_relocate_contents (howto, input_bfd, relocation,
1436 contents + address);
1437 }
1438
1439 /* Relocate a given location using a given value and howto. */
1440
1441 bfd_reloc_status_type
1442 _bfd_relocate_contents (howto, input_bfd, relocation, location)
1443 reloc_howto_type *howto;
1444 bfd *input_bfd;
1445 bfd_vma relocation;
1446 bfd_byte *location;
1447 {
1448 int size;
1449 bfd_vma x;
1450 boolean overflow;
1451
1452 /* If the size is negative, negate RELOCATION. This isn't very
1453 general. */
1454 if (howto->size < 0)
1455 relocation = -relocation;
1456
1457 /* Get the value we are going to relocate. */
1458 size = bfd_get_reloc_size (howto);
1459 switch (size)
1460 {
1461 default:
1462 case 0:
1463 abort ();
1464 case 1:
1465 x = bfd_get_8 (input_bfd, location);
1466 break;
1467 case 2:
1468 x = bfd_get_16 (input_bfd, location);
1469 break;
1470 case 4:
1471 x = bfd_get_32 (input_bfd, location);
1472 break;
1473 case 8:
1474 #ifdef BFD64
1475 x = bfd_get_64 (input_bfd, location);
1476 #else
1477 abort ();
1478 #endif
1479 break;
1480 }
1481
1482 /* Check for overflow. FIXME: We may drop bits during the addition
1483 which we don't check for. We must either check at every single
1484 operation, which would be tedious, or we must do the computations
1485 in a type larger than bfd_vma, which would be inefficient. */
1486 overflow = false;
1487 if (howto->complain_on_overflow != complain_overflow_dont)
1488 {
1489 bfd_vma check;
1490 bfd_signed_vma signed_check;
1491 bfd_vma add;
1492 bfd_signed_vma signed_add;
1493
1494 if (howto->rightshift == 0)
1495 {
1496 check = relocation;
1497 signed_check = (bfd_signed_vma) relocation;
1498 }
1499 else
1500 {
1501 /* Drop unwanted bits from the value we are relocating to. */
1502 check = relocation >> howto->rightshift;
1503
1504 /* If this is a signed value, the rightshift just dropped
1505 leading 1 bits (assuming twos complement). */
1506 if ((bfd_signed_vma) relocation >= 0)
1507 signed_check = check;
1508 else
1509 signed_check = (check
1510 | ((bfd_vma) - 1
1511 & ~((bfd_vma) - 1 >> howto->rightshift)));
1512 }
1513
1514 /* Get the value from the object file. */
1515 add = x & howto->src_mask;
1516
1517 /* Get the value from the object file with an appropriate sign.
1518 The expression involving howto->src_mask isolates the upper
1519 bit of src_mask. If that bit is set in the value we are
1520 adding, it is negative, and we subtract out that number times
1521 two. If src_mask includes the highest possible bit, then we
1522 can not get the upper bit, but that does not matter since
1523 signed_add needs no adjustment to become negative in that
1524 case. */
1525 signed_add = add;
1526 if ((add & (((~howto->src_mask) >> 1) & howto->src_mask)) != 0)
1527 signed_add -= (((~howto->src_mask) >> 1) & howto->src_mask) << 1;
1528
1529 /* Add the value from the object file, shifted so that it is a
1530 straight number. */
1531 if (howto->bitpos == 0)
1532 {
1533 check += add;
1534 signed_check += signed_add;
1535 }
1536 else
1537 {
1538 check += add >> howto->bitpos;
1539
1540 /* For the signed case we use ADD, rather than SIGNED_ADD,
1541 to avoid warnings from SVR4 cc. This is OK since we
1542 explictly handle the sign bits. */
1543 if (signed_add >= 0)
1544 signed_check += add >> howto->bitpos;
1545 else
1546 signed_check += ((add >> howto->bitpos)
1547 | ((bfd_vma) - 1
1548 & ~((bfd_vma) - 1 >> howto->bitpos)));
1549 }
1550
1551 switch (howto->complain_on_overflow)
1552 {
1553 case complain_overflow_signed:
1554 {
1555 /* Assumes two's complement. */
1556 bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
1557 bfd_signed_vma reloc_signed_min = ~reloc_signed_max;
1558
1559 if (signed_check > reloc_signed_max
1560 || signed_check < reloc_signed_min)
1561 overflow = true;
1562 }
1563 break;
1564 case complain_overflow_unsigned:
1565 {
1566 /* Assumes two's complement. This expression avoids
1567 overflow if howto->bitsize is the number of bits in
1568 bfd_vma. */
1569 bfd_vma reloc_unsigned_max =
1570 (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1571
1572 if (check > reloc_unsigned_max)
1573 overflow = true;
1574 }
1575 break;
1576 case complain_overflow_bitfield:
1577 {
1578 /* Assumes two's complement. This expression avoids
1579 overflow if howto->bitsize is the number of bits in
1580 bfd_vma. */
1581 bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
1582
1583 if ((check & ~reloc_bits) != 0
1584 && (((bfd_vma) signed_check & ~reloc_bits)
1585 != (-1 & ~reloc_bits)))
1586 overflow = true;
1587 }
1588 break;
1589 default:
1590 abort ();
1591 }
1592 }
1593
1594 /* Put RELOCATION in the right bits. */
1595 relocation >>= (bfd_vma) howto->rightshift;
1596 relocation <<= (bfd_vma) howto->bitpos;
1597
1598 /* Add RELOCATION to the right bits of X. */
1599 x = ((x & ~howto->dst_mask)
1600 | (((x & howto->src_mask) + relocation) & howto->dst_mask));
1601
1602 /* Put the relocated value back in the object file. */
1603 switch (size)
1604 {
1605 default:
1606 case 0:
1607 abort ();
1608 case 1:
1609 bfd_put_8 (input_bfd, x, location);
1610 break;
1611 case 2:
1612 bfd_put_16 (input_bfd, x, location);
1613 break;
1614 case 4:
1615 bfd_put_32 (input_bfd, x, location);
1616 break;
1617 case 8:
1618 #ifdef BFD64
1619 bfd_put_64 (input_bfd, x, location);
1620 #else
1621 abort ();
1622 #endif
1623 break;
1624 }
1625
1626 return overflow ? bfd_reloc_overflow : bfd_reloc_ok;
1627 }
1628
1629 /*
1630 DOCDD
1631 INODE
1632 howto manager, , typedef arelent, Relocations
1633
1634 SECTION
1635 The howto manager
1636
1637 When an application wants to create a relocation, but doesn't
1638 know what the target machine might call it, it can find out by
1639 using this bit of code.
1640
1641 */
1642
1643 /*
1644 TYPEDEF
1645 bfd_reloc_code_type
1646
1647 DESCRIPTION
1648 The insides of a reloc code. The idea is that, eventually, there
1649 will be one enumerator for every type of relocation we ever do.
1650 Pass one of these values to <<bfd_reloc_type_lookup>>, and it'll
1651 return a howto pointer.
1652
1653 This does mean that the application must determine the correct
1654 enumerator value; you can't get a howto pointer from a random set
1655 of attributes.
1656
1657 SENUM
1658 bfd_reloc_code_real
1659
1660 ENUM
1661 BFD_RELOC_64
1662 ENUMX
1663 BFD_RELOC_32
1664 ENUMX
1665 BFD_RELOC_26
1666 ENUMX
1667 BFD_RELOC_24
1668 ENUMX
1669 BFD_RELOC_16
1670 ENUMX
1671 BFD_RELOC_14
1672 ENUMX
1673 BFD_RELOC_8
1674 ENUMDOC
1675 Basic absolute relocations of N bits.
1676
1677 ENUM
1678 BFD_RELOC_64_PCREL
1679 ENUMX
1680 BFD_RELOC_32_PCREL
1681 ENUMX
1682 BFD_RELOC_24_PCREL
1683 ENUMX
1684 BFD_RELOC_16_PCREL
1685 ENUMX
1686 BFD_RELOC_12_PCREL
1687 ENUMX
1688 BFD_RELOC_8_PCREL
1689 ENUMDOC
1690 PC-relative relocations. Sometimes these are relative to the address
1691 of the relocation itself; sometimes they are relative to the start of
1692 the section containing the relocation. It depends on the specific target.
1693
1694 The 24-bit relocation is used in some Intel 960 configurations.
1695
1696 ENUM
1697 BFD_RELOC_32_GOT_PCREL
1698 ENUMX
1699 BFD_RELOC_16_GOT_PCREL
1700 ENUMX
1701 BFD_RELOC_8_GOT_PCREL
1702 ENUMX
1703 BFD_RELOC_32_GOTOFF
1704 ENUMX
1705 BFD_RELOC_16_GOTOFF
1706 ENUMX
1707 BFD_RELOC_LO16_GOTOFF
1708 ENUMX
1709 BFD_RELOC_HI16_GOTOFF
1710 ENUMX
1711 BFD_RELOC_HI16_S_GOTOFF
1712 ENUMX
1713 BFD_RELOC_8_GOTOFF
1714 ENUMX
1715 BFD_RELOC_32_PLT_PCREL
1716 ENUMX
1717 BFD_RELOC_24_PLT_PCREL
1718 ENUMX
1719 BFD_RELOC_16_PLT_PCREL
1720 ENUMX
1721 BFD_RELOC_8_PLT_PCREL
1722 ENUMX
1723 BFD_RELOC_32_PLTOFF
1724 ENUMX
1725 BFD_RELOC_16_PLTOFF
1726 ENUMX
1727 BFD_RELOC_LO16_PLTOFF
1728 ENUMX
1729 BFD_RELOC_HI16_PLTOFF
1730 ENUMX
1731 BFD_RELOC_HI16_S_PLTOFF
1732 ENUMX
1733 BFD_RELOC_8_PLTOFF
1734 ENUMDOC
1735 For ELF.
1736
1737 ENUM
1738 BFD_RELOC_68K_GLOB_DAT
1739 ENUMX
1740 BFD_RELOC_68K_JMP_SLOT
1741 ENUMX
1742 BFD_RELOC_68K_RELATIVE
1743 ENUMDOC
1744 Relocations used by 68K ELF.
1745
1746 ENUM
1747 BFD_RELOC_32_BASEREL
1748 ENUMX
1749 BFD_RELOC_16_BASEREL
1750 ENUMX
1751 BFD_RELOC_LO16_BASEREL
1752 ENUMX
1753 BFD_RELOC_HI16_BASEREL
1754 ENUMX
1755 BFD_RELOC_HI16_S_BASEREL
1756 ENUMX
1757 BFD_RELOC_8_BASEREL
1758 ENUMX
1759 BFD_RELOC_RVA
1760 ENUMDOC
1761 Linkage-table relative.
1762
1763 ENUM
1764 BFD_RELOC_8_FFnn
1765 ENUMDOC
1766 Absolute 8-bit relocation, but used to form an address like 0xFFnn.
1767
1768 ENUM
1769 BFD_RELOC_32_PCREL_S2
1770 ENUMX
1771 BFD_RELOC_16_PCREL_S2
1772 ENUMX
1773 BFD_RELOC_23_PCREL_S2
1774 ENUMDOC
1775 These PC-relative relocations are stored as word displacements --
1776 i.e., byte displacements shifted right two bits. The 30-bit word
1777 displacement (<<32_PCREL_S2>> -- 32 bits, shifted 2) is used on the
1778 SPARC. (SPARC tools generally refer to this as <<WDISP30>>.) The
1779 signed 16-bit displacement is used on the MIPS, and the 23-bit
1780 displacement is used on the Alpha.
1781
1782 ENUM
1783 BFD_RELOC_HI22
1784 ENUMX
1785 BFD_RELOC_LO10
1786 ENUMDOC
1787 High 22 bits and low 10 bits of 32-bit value, placed into lower bits of
1788 the target word. These are used on the SPARC.
1789
1790 ENUM
1791 BFD_RELOC_GPREL16
1792 ENUMX
1793 BFD_RELOC_GPREL32
1794 ENUMDOC
1795 For systems that allocate a Global Pointer register, these are
1796 displacements off that register. These relocation types are
1797 handled specially, because the value the register will have is
1798 decided relatively late.
1799
1800
1801 ENUM
1802 BFD_RELOC_I960_CALLJ
1803 ENUMDOC
1804 Reloc types used for i960/b.out.
1805
1806 ENUM
1807 BFD_RELOC_NONE
1808 ENUMX
1809 BFD_RELOC_SPARC_WDISP22
1810 ENUMX
1811 BFD_RELOC_SPARC22
1812 ENUMX
1813 BFD_RELOC_SPARC13
1814 ENUMX
1815 BFD_RELOC_SPARC_GOT10
1816 ENUMX
1817 BFD_RELOC_SPARC_GOT13
1818 ENUMX
1819 BFD_RELOC_SPARC_GOT22
1820 ENUMX
1821 BFD_RELOC_SPARC_PC10
1822 ENUMX
1823 BFD_RELOC_SPARC_PC22
1824 ENUMX
1825 BFD_RELOC_SPARC_WPLT30
1826 ENUMX
1827 BFD_RELOC_SPARC_COPY
1828 ENUMX
1829 BFD_RELOC_SPARC_GLOB_DAT
1830 ENUMX
1831 BFD_RELOC_SPARC_JMP_SLOT
1832 ENUMX
1833 BFD_RELOC_SPARC_RELATIVE
1834 ENUMX
1835 BFD_RELOC_SPARC_UA32
1836 ENUMDOC
1837 SPARC ELF relocations. There is probably some overlap with other
1838 relocation types already defined.
1839
1840 ENUM
1841 BFD_RELOC_SPARC_BASE13
1842 ENUMX
1843 BFD_RELOC_SPARC_BASE22
1844 ENUMDOC
1845 I think these are specific to SPARC a.out (e.g., Sun 4).
1846
1847 ENUMEQ
1848 BFD_RELOC_SPARC_64
1849 BFD_RELOC_64
1850 ENUMX
1851 BFD_RELOC_SPARC_10
1852 ENUMX
1853 BFD_RELOC_SPARC_11
1854 ENUMX
1855 BFD_RELOC_SPARC_OLO10
1856 ENUMX
1857 BFD_RELOC_SPARC_HH22
1858 ENUMX
1859 BFD_RELOC_SPARC_HM10
1860 ENUMX
1861 BFD_RELOC_SPARC_LM22
1862 ENUMX
1863 BFD_RELOC_SPARC_PC_HH22
1864 ENUMX
1865 BFD_RELOC_SPARC_PC_HM10
1866 ENUMX
1867 BFD_RELOC_SPARC_PC_LM22
1868 ENUMX
1869 BFD_RELOC_SPARC_WDISP16
1870 ENUMX
1871 BFD_RELOC_SPARC_WDISP19
1872 ENUMX
1873 BFD_RELOC_SPARC_GLOB_JMP
1874 ENUMX
1875 BFD_RELOC_SPARC_7
1876 ENUMX
1877 BFD_RELOC_SPARC_6
1878 ENUMX
1879 BFD_RELOC_SPARC_5
1880 ENUMDOC
1881 Some relocations we're using for SPARC V9 -- subject to change.
1882
1883 ENUM
1884 BFD_RELOC_ALPHA_GPDISP_HI16
1885 ENUMDOC
1886 Alpha ECOFF and ELF relocations. Some of these treat the symbol or
1887 "addend" in some special way.
1888 For GPDISP_HI16 ("gpdisp") relocations, the symbol is ignored when
1889 writing; when reading, it will be the absolute section symbol. The
1890 addend is the displacement in bytes of the "lda" instruction from
1891 the "ldah" instruction (which is at the address of this reloc).
1892 ENUM
1893 BFD_RELOC_ALPHA_GPDISP_LO16
1894 ENUMDOC
1895 For GPDISP_LO16 ("ignore") relocations, the symbol is handled as
1896 with GPDISP_HI16 relocs. The addend is ignored when writing the
1897 relocations out, and is filled in with the file's GP value on
1898 reading, for convenience.
1899
1900 ENUM
1901 BFD_RELOC_ALPHA_GPDISP
1902 ENUMDOC
1903 The ELF GPDISP relocation is exactly the same as the GPDISP_HI16
1904 relocation except that there is no accompanying GPDISP_LO16
1905 relocation.
1906
1907 ENUM
1908 BFD_RELOC_ALPHA_LITERAL
1909 ENUMX
1910 BFD_RELOC_ALPHA_ELF_LITERAL
1911 ENUMX
1912 BFD_RELOC_ALPHA_LITUSE
1913 ENUMDOC
1914 The Alpha LITERAL/LITUSE relocs are produced by a symbol reference;
1915 the assembler turns it into a LDQ instruction to load the address of
1916 the symbol, and then fills in a register in the real instruction.
1917
1918 The LITERAL reloc, at the LDQ instruction, refers to the .lita
1919 section symbol. The addend is ignored when writing, but is filled
1920 in with the file's GP value on reading, for convenience, as with the
1921 GPDISP_LO16 reloc.
1922
1923 The ELF_LITERAL reloc is somewhere between 16_GOTOFF and GPDISP_LO16.
1924 It should refer to the symbol to be referenced, as with 16_GOTOFF,
1925 but it generates output not based on the position within the .got
1926 section, but relative to the GP value chosen for the file during the
1927 final link stage.
1928
1929 The LITUSE reloc, on the instruction using the loaded address, gives
1930 information to the linker that it might be able to use to optimize
1931 away some literal section references. The symbol is ignored (read
1932 as the absolute section symbol), and the "addend" indicates the type
1933 of instruction using the register:
1934 1 - "memory" fmt insn
1935 2 - byte-manipulation (byte offset reg)
1936 3 - jsr (target of branch)
1937
1938 The GNU linker currently doesn't do any of this optimizing.
1939
1940 ENUM
1941 BFD_RELOC_ALPHA_HINT
1942 ENUMDOC
1943 The HINT relocation indicates a value that should be filled into the
1944 "hint" field of a jmp/jsr/ret instruction, for possible branch-
1945 prediction logic which may be provided on some processors.
1946
1947 ENUM
1948 BFD_RELOC_ALPHA_LINKAGE
1949 ENUMDOC
1950 The LINKAGE relocation outputs a linkage pair in the object file,
1951 which is filled by the linker.
1952
1953 ENUM
1954 BFD_RELOC_ALPHA_CODEADDR
1955 ENUMDOC
1956 The CODEADDR relocation outputs a STO_CA in the object file,
1957 which is filled by the linker.
1958
1959 ENUM
1960 BFD_RELOC_MIPS_JMP
1961 ENUMDOC
1962 Bits 27..2 of the relocation address shifted right 2 bits;
1963 simple reloc otherwise.
1964
1965 ENUM
1966 BFD_RELOC_MIPS16_JMP
1967 ENUMDOC
1968 The MIPS16 jump instruction.
1969
1970 ENUM
1971 BFD_RELOC_MIPS16_GPREL
1972 ENUMDOC
1973 MIPS16 GP relative reloc.
1974
1975 ENUM
1976 BFD_RELOC_HI16
1977 ENUMDOC
1978 High 16 bits of 32-bit value; simple reloc.
1979 ENUM
1980 BFD_RELOC_HI16_S
1981 ENUMDOC
1982 High 16 bits of 32-bit value but the low 16 bits will be sign
1983 extended and added to form the final result. If the low 16
1984 bits form a negative number, we need to add one to the high value
1985 to compensate for the borrow when the low bits are added.
1986 ENUM
1987 BFD_RELOC_LO16
1988 ENUMDOC
1989 Low 16 bits.
1990 ENUM
1991 BFD_RELOC_PCREL_HI16_S
1992 ENUMDOC
1993 Like BFD_RELOC_HI16_S, but PC relative.
1994 ENUM
1995 BFD_RELOC_PCREL_LO16
1996 ENUMDOC
1997 Like BFD_RELOC_LO16, but PC relative.
1998
1999 ENUMEQ
2000 BFD_RELOC_MIPS_GPREL
2001 BFD_RELOC_GPREL16
2002 ENUMDOC
2003 Relocation relative to the global pointer.
2004
2005 ENUM
2006 BFD_RELOC_MIPS_LITERAL
2007 ENUMDOC
2008 Relocation against a MIPS literal section.
2009
2010 ENUM
2011 BFD_RELOC_MIPS_GOT16
2012 ENUMX
2013 BFD_RELOC_MIPS_CALL16
2014 ENUMEQX
2015 BFD_RELOC_MIPS_GPREL32
2016 BFD_RELOC_GPREL32
2017 ENUMX
2018 BFD_RELOC_MIPS_GOT_HI16
2019 ENUMX
2020 BFD_RELOC_MIPS_GOT_LO16
2021 ENUMX
2022 BFD_RELOC_MIPS_CALL_HI16
2023 ENUMX
2024 BFD_RELOC_MIPS_CALL_LO16
2025 ENUMDOC
2026 MIPS ELF relocations.
2027
2028 ENUM
2029 BFD_RELOC_386_GOT32
2030 ENUMX
2031 BFD_RELOC_386_PLT32
2032 ENUMX
2033 BFD_RELOC_386_COPY
2034 ENUMX
2035 BFD_RELOC_386_GLOB_DAT
2036 ENUMX
2037 BFD_RELOC_386_JUMP_SLOT
2038 ENUMX
2039 BFD_RELOC_386_RELATIVE
2040 ENUMX
2041 BFD_RELOC_386_GOTOFF
2042 ENUMX
2043 BFD_RELOC_386_GOTPC
2044 ENUMDOC
2045 i386/elf relocations
2046
2047 ENUM
2048 BFD_RELOC_NS32K_IMM_8
2049 ENUMX
2050 BFD_RELOC_NS32K_IMM_16
2051 ENUMX
2052 BFD_RELOC_NS32K_IMM_32
2053 ENUMX
2054 BFD_RELOC_NS32K_IMM_8_PCREL
2055 ENUMX
2056 BFD_RELOC_NS32K_IMM_16_PCREL
2057 ENUMX
2058 BFD_RELOC_NS32K_IMM_32_PCREL
2059 ENUMX
2060 BFD_RELOC_NS32K_DISP_8
2061 ENUMX
2062 BFD_RELOC_NS32K_DISP_16
2063 ENUMX
2064 BFD_RELOC_NS32K_DISP_32
2065 ENUMX
2066 BFD_RELOC_NS32K_DISP_8_PCREL
2067 ENUMX
2068 BFD_RELOC_NS32K_DISP_16_PCREL
2069 ENUMX
2070 BFD_RELOC_NS32K_DISP_32_PCREL
2071 ENUMDOC
2072 ns32k relocations
2073
2074 ENUM
2075 BFD_RELOC_PPC_B26
2076 ENUMX
2077 BFD_RELOC_PPC_BA26
2078 ENUMX
2079 BFD_RELOC_PPC_TOC16
2080 ENUMX
2081 BFD_RELOC_PPC_B16
2082 ENUMX
2083 BFD_RELOC_PPC_B16_BRTAKEN
2084 ENUMX
2085 BFD_RELOC_PPC_B16_BRNTAKEN
2086 ENUMX
2087 BFD_RELOC_PPC_BA16
2088 ENUMX
2089 BFD_RELOC_PPC_BA16_BRTAKEN
2090 ENUMX
2091 BFD_RELOC_PPC_BA16_BRNTAKEN
2092 ENUMX
2093 BFD_RELOC_PPC_COPY
2094 ENUMX
2095 BFD_RELOC_PPC_GLOB_DAT
2096 ENUMX
2097 BFD_RELOC_PPC_JMP_SLOT
2098 ENUMX
2099 BFD_RELOC_PPC_RELATIVE
2100 ENUMX
2101 BFD_RELOC_PPC_LOCAL24PC
2102 ENUMX
2103 BFD_RELOC_PPC_EMB_NADDR32
2104 ENUMX
2105 BFD_RELOC_PPC_EMB_NADDR16
2106 ENUMX
2107 BFD_RELOC_PPC_EMB_NADDR16_LO
2108 ENUMX
2109 BFD_RELOC_PPC_EMB_NADDR16_HI
2110 ENUMX
2111 BFD_RELOC_PPC_EMB_NADDR16_HA
2112 ENUMX
2113 BFD_RELOC_PPC_EMB_SDAI16
2114 ENUMX
2115 BFD_RELOC_PPC_EMB_SDA2I16
2116 ENUMX
2117 BFD_RELOC_PPC_EMB_SDA2REL
2118 ENUMX
2119 BFD_RELOC_PPC_EMB_SDA21
2120 ENUMX
2121 BFD_RELOC_PPC_EMB_MRKREF
2122 ENUMX
2123 BFD_RELOC_PPC_EMB_RELSEC16
2124 ENUMX
2125 BFD_RELOC_PPC_EMB_RELST_LO
2126 ENUMX
2127 BFD_RELOC_PPC_EMB_RELST_HI
2128 ENUMX
2129 BFD_RELOC_PPC_EMB_RELST_HA
2130 ENUMX
2131 BFD_RELOC_PPC_EMB_BIT_FLD
2132 ENUMX
2133 BFD_RELOC_PPC_EMB_RELSDA
2134 ENUMDOC
2135 Power(rs6000) and PowerPC relocations.
2136
2137 ENUM
2138 BFD_RELOC_CTOR
2139 ENUMDOC
2140 The type of reloc used to build a contructor table - at the moment
2141 probably a 32 bit wide absolute relocation, but the target can choose.
2142 It generally does map to one of the other relocation types.
2143
2144 ENUM
2145 BFD_RELOC_ARM_PCREL_BRANCH
2146 ENUMDOC
2147 ARM 26 bit pc-relative branch. The lowest two bits must be zero and are
2148 not stored in the instruction.
2149 ENUM
2150 BFD_RELOC_ARM_IMMEDIATE
2151 ENUMX
2152 BFD_RELOC_ARM_OFFSET_IMM
2153 ENUMX
2154 BFD_RELOC_ARM_SHIFT_IMM
2155 ENUMX
2156 BFD_RELOC_ARM_SWI
2157 ENUMX
2158 BFD_RELOC_ARM_MULTI
2159 ENUMX
2160 BFD_RELOC_ARM_CP_OFF_IMM
2161 ENUMX
2162 BFD_RELOC_ARM_ADR_IMM
2163 ENUMX
2164 BFD_RELOC_ARM_LDR_IMM
2165 ENUMX
2166 BFD_RELOC_ARM_LITERAL
2167 ENUMX
2168 BFD_RELOC_ARM_IN_POOL
2169 ENUMX
2170 BFD_RELOC_ARM_OFFSET_IMM8
2171 ENUMX
2172 BFD_RELOC_ARM_HWLITERAL
2173 ENUMX
2174 BFD_RELOC_ARM_THUMB_ADD
2175 ENUMX
2176 BFD_RELOC_ARM_THUMB_IMM
2177 ENUMX
2178 BFD_RELOC_ARM_THUMB_SHIFT
2179 ENUMX
2180 BFD_RELOC_ARM_THUMB_OFFSET
2181 ENUMDOC
2182 These relocs are only used within the ARM assembler. They are not
2183 (at present) written to any object files.
2184
2185 ENUM
2186 BFD_RELOC_SH_PCDISP8BY2
2187 ENUMX
2188 BFD_RELOC_SH_PCDISP12BY2
2189 ENUMX
2190 BFD_RELOC_SH_IMM4
2191 ENUMX
2192 BFD_RELOC_SH_IMM4BY2
2193 ENUMX
2194 BFD_RELOC_SH_IMM4BY4
2195 ENUMX
2196 BFD_RELOC_SH_IMM8
2197 ENUMX
2198 BFD_RELOC_SH_IMM8BY2
2199 ENUMX
2200 BFD_RELOC_SH_IMM8BY4
2201 ENUMX
2202 BFD_RELOC_SH_PCRELIMM8BY2
2203 ENUMX
2204 BFD_RELOC_SH_PCRELIMM8BY4
2205 ENUMX
2206 BFD_RELOC_SH_SWITCH16
2207 ENUMX
2208 BFD_RELOC_SH_SWITCH32
2209 ENUMX
2210 BFD_RELOC_SH_USES
2211 ENUMX
2212 BFD_RELOC_SH_COUNT
2213 ENUMX
2214 BFD_RELOC_SH_ALIGN
2215 ENUMX
2216 BFD_RELOC_SH_CODE
2217 ENUMX
2218 BFD_RELOC_SH_DATA
2219 ENUMX
2220 BFD_RELOC_SH_LABEL
2221 ENUMDOC
2222 Hitachi SH relocs. Not all of these appear in object files.
2223
2224 COMMENT
2225 {* start-sanitize-arc *}
2226 ENUM
2227 BFD_RELOC_ARC_B22_PCREL
2228 ENUMDOC
2229 Argonaut RISC Core (ARC) relocs.
2230 ARC 22 bit pc-relative branch. The lowest two bits must be zero and are
2231 not stored in the instruction. The high 20 bits are installed in bits 26
2232 through 7 of the instruction.
2233 ENUM
2234 BFD_RELOC_ARC_B26
2235 ENUMDOC
2236 ARC 26 bit absolute branch. The lowest two bits must be zero and are not
2237 stored in the instruction. The high 24 bits are installed in bits 23
2238 through 0.
2239 COMMENT
2240 {* end-sanitize-arc *}
2241
2242 COMMENT
2243 {* start-sanitize-d10v *}
2244 ENUM
2245 BFD_RELOC_D10V_10_PCREL_R
2246 ENUMDOC
2247 Mitsubishi D10V relocs.
2248 This is a 10-bit reloc with the right 2 bits
2249 assumed to be 0.
2250 ENUM
2251 BFD_RELOC_D10V_10_PCREL_L
2252 ENUMDOC
2253 Mitsubishi D10V relocs.
2254 This is a 10-bit reloc with the right 2 bits
2255 assumed to be 0. This is the same as the previous reloc
2256 except it is in the left container, i.e.,
2257 shifted left 15 bits.
2258 ENUM
2259 BFD_RELOC_D10V_18
2260 ENUMDOC
2261 This is an 18-bit reloc with the right 2 bits
2262 assumed to be 0.
2263 ENUM
2264 BFD_RELOC_D10V_18_PCREL
2265 ENUMDOC
2266 This is an 18-bit reloc with the right 2 bits
2267 assumed to be 0.
2268 COMMENT
2269 {* end-sanitize-d10v *}
2270
2271 COMMENT
2272 {* start-sanitize-m32r *}
2273 ENUM
2274 BFD_RELOC_M32R_24
2275 ENUMDOC
2276 Mitsubishi M32R relocs.
2277 This is a 24 bit absolute address.
2278 ENUM
2279 BFD_RELOC_M32R_10_PCREL
2280 ENUMDOC
2281 This is a 10-bit pc-relative reloc with the right 2 bits assumed to be 0.
2282 ENUM
2283 BFD_RELOC_M32R_18_PCREL
2284 ENUMDOC
2285 This is an 18-bit reloc with the right 2 bits assumed to be 0.
2286 ENUM
2287 BFD_RELOC_M32R_26_PCREL
2288 ENUMDOC
2289 This is a 26-bit reloc with the right 2 bits assumed to be 0.
2290 ENUM
2291 BFD_RELOC_M32R_HI16_ULO
2292 ENUMDOC
2293 This is a 16-bit reloc containing the high 16 bits of an address
2294 used when the lower 16 bits are treated as unsigned.
2295 ENUM
2296 BFD_RELOC_M32R_HI16_SLO
2297 ENUMDOC
2298 This is a 16-bit reloc containing the high 16 bits of an address
2299 used when the lower 16 bits are treated as signed.
2300 ENUM
2301 BFD_RELOC_M32R_LO16
2302 ENUMDOC
2303 This is a 16-bit reloc containing the lower 16 bits of an address.
2304 COMMENT
2305 {* end-sanitize-m32r *}
2306
2307 COMMENT
2308 {* start-sanitize-v850 *}
2309 ENUM
2310 BFD_RELOC_V850_9_PCREL
2311 ENUMDOC
2312 This is a 9-bit reloc
2313 ENUM
2314 BFD_RELOC_V850_22_PCREL
2315 ENUMDOC
2316 This is a 22-bit reloc
2317 ENUM
2318 BFD_RELOC_V850_SDA_OFFSET
2319 ENUMDOC
2320 This is an offset from the short data area pointer..
2321 ENUM
2322 BFD_RELOC_V850_ZDA_OFFSET
2323 ENUMDOC
2324 This is an offset from the zero data area pointer..
2325 ENUM
2326 BFD_RELOC_V850_TDA_OFFSET
2327 ENUMDOC
2328 This is an offset from the tiny data area pointer..
2329 COMMENT
2330 {* end-sanitize-v850 *}
2331
2332 ENUM
2333 BFD_RELOC_MN10300_32_PCREL
2334 ENUMDOC
2335 This is a 32bit pcrel reloc for the mn10300, offset by two bytes in the
2336 instruction.
2337 ENUM
2338 BFD_RELOC_MN10300_16_PCREL
2339 ENUMDOC
2340 This is a 16bit pcrel reloc for the mn10300, offset by two bytes in the
2341 instruction.
2342 ENDSENUM
2343 BFD_RELOC_UNUSED
2344 CODE_FRAGMENT
2345 .
2346 .typedef enum bfd_reloc_code_real bfd_reloc_code_real_type;
2347 */
2348
2349
2350 /*
2351 FUNCTION
2352 bfd_reloc_type_lookup
2353
2354 SYNOPSIS
2355 reloc_howto_type *
2356 bfd_reloc_type_lookup (bfd *abfd, bfd_reloc_code_real_type code);
2357
2358 DESCRIPTION
2359 Return a pointer to a howto structure which, when
2360 invoked, will perform the relocation @var{code} on data from the
2361 architecture noted.
2362
2363 */
2364
2365
2366 reloc_howto_type *
2367 bfd_reloc_type_lookup (abfd, code)
2368 bfd *abfd;
2369 bfd_reloc_code_real_type code;
2370 {
2371 return BFD_SEND (abfd, reloc_type_lookup, (abfd, code));
2372 }
2373
2374 static reloc_howto_type bfd_howto_32 =
2375 HOWTO (0, 00, 2, 32, false, 0, complain_overflow_bitfield, 0, "VRT32", false, 0xffffffff, 0xffffffff, true);
2376
2377
2378 /*
2379 INTERNAL_FUNCTION
2380 bfd_default_reloc_type_lookup
2381
2382 SYNOPSIS
2383 reloc_howto_type *bfd_default_reloc_type_lookup
2384 (bfd *abfd, bfd_reloc_code_real_type code);
2385
2386 DESCRIPTION
2387 Provides a default relocation lookup routine for any architecture.
2388
2389
2390 */
2391
2392 reloc_howto_type *
2393 bfd_default_reloc_type_lookup (abfd, code)
2394 bfd *abfd;
2395 bfd_reloc_code_real_type code;
2396 {
2397 switch (code)
2398 {
2399 case BFD_RELOC_CTOR:
2400 /* The type of reloc used in a ctor, which will be as wide as the
2401 address - so either a 64, 32, or 16 bitter. */
2402 switch (bfd_get_arch_info (abfd)->bits_per_address)
2403 {
2404 case 64:
2405 BFD_FAIL ();
2406 case 32:
2407 return &bfd_howto_32;
2408 case 16:
2409 BFD_FAIL ();
2410 default:
2411 BFD_FAIL ();
2412 }
2413 default:
2414 BFD_FAIL ();
2415 }
2416 return (reloc_howto_type *) NULL;
2417 }
2418
2419 /*
2420 FUNCTION
2421 bfd_get_reloc_code_name
2422
2423 SYNOPSIS
2424 const char *bfd_get_reloc_code_name (bfd_reloc_code_real_type code);
2425
2426 DESCRIPTION
2427 Provides a printable name for the supplied relocation code.
2428 Useful mainly for printing error messages.
2429 */
2430
2431 const char *
2432 bfd_get_reloc_code_name (code)
2433 bfd_reloc_code_real_type code;
2434 {
2435 if (code > BFD_RELOC_UNUSED)
2436 return 0;
2437 return bfd_reloc_code_real_names[(int)code];
2438 }
2439
2440 /*
2441 INTERNAL_FUNCTION
2442 bfd_generic_relax_section
2443
2444 SYNOPSIS
2445 boolean bfd_generic_relax_section
2446 (bfd *abfd,
2447 asection *section,
2448 struct bfd_link_info *,
2449 boolean *);
2450
2451 DESCRIPTION
2452 Provides default handling for relaxing for back ends which
2453 don't do relaxing -- i.e., does nothing.
2454 */
2455
2456 /*ARGSUSED*/
2457 boolean
2458 bfd_generic_relax_section (abfd, section, link_info, again)
2459 bfd *abfd;
2460 asection *section;
2461 struct bfd_link_info *link_info;
2462 boolean *again;
2463 {
2464 *again = false;
2465 return true;
2466 }
2467
2468 /*
2469 INTERNAL_FUNCTION
2470 bfd_generic_get_relocated_section_contents
2471
2472 SYNOPSIS
2473 bfd_byte *
2474 bfd_generic_get_relocated_section_contents (bfd *abfd,
2475 struct bfd_link_info *link_info,
2476 struct bfd_link_order *link_order,
2477 bfd_byte *data,
2478 boolean relocateable,
2479 asymbol **symbols);
2480
2481 DESCRIPTION
2482 Provides default handling of relocation effort for back ends
2483 which can't be bothered to do it efficiently.
2484
2485 */
2486
2487 bfd_byte *
2488 bfd_generic_get_relocated_section_contents (abfd, link_info, link_order, data,
2489 relocateable, symbols)
2490 bfd *abfd;
2491 struct bfd_link_info *link_info;
2492 struct bfd_link_order *link_order;
2493 bfd_byte *data;
2494 boolean relocateable;
2495 asymbol **symbols;
2496 {
2497 /* Get enough memory to hold the stuff */
2498 bfd *input_bfd = link_order->u.indirect.section->owner;
2499 asection *input_section = link_order->u.indirect.section;
2500
2501 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section);
2502 arelent **reloc_vector = NULL;
2503 long reloc_count;
2504
2505 if (reloc_size < 0)
2506 goto error_return;
2507
2508 reloc_vector = (arelent **) bfd_malloc ((size_t) reloc_size);
2509 if (reloc_vector == NULL && reloc_size != 0)
2510 goto error_return;
2511
2512 /* read in the section */
2513 if (!bfd_get_section_contents (input_bfd,
2514 input_section,
2515 (PTR) data,
2516 0,
2517 input_section->_raw_size))
2518 goto error_return;
2519
2520 /* We're not relaxing the section, so just copy the size info */
2521 input_section->_cooked_size = input_section->_raw_size;
2522 input_section->reloc_done = true;
2523
2524 reloc_count = bfd_canonicalize_reloc (input_bfd,
2525 input_section,
2526 reloc_vector,
2527 symbols);
2528 if (reloc_count < 0)
2529 goto error_return;
2530
2531 if (reloc_count > 0)
2532 {
2533 arelent **parent;
2534 for (parent = reloc_vector; *parent != (arelent *) NULL;
2535 parent++)
2536 {
2537 char *error_message = (char *) NULL;
2538 bfd_reloc_status_type r =
2539 bfd_perform_relocation (input_bfd,
2540 *parent,
2541 (PTR) data,
2542 input_section,
2543 relocateable ? abfd : (bfd *) NULL,
2544 &error_message);
2545
2546 if (relocateable)
2547 {
2548 asection *os = input_section->output_section;
2549
2550 /* A partial link, so keep the relocs */
2551 os->orelocation[os->reloc_count] = *parent;
2552 os->reloc_count++;
2553 }
2554
2555 if (r != bfd_reloc_ok)
2556 {
2557 switch (r)
2558 {
2559 case bfd_reloc_undefined:
2560 if (!((*link_info->callbacks->undefined_symbol)
2561 (link_info, bfd_asymbol_name (*(*parent)->sym_ptr_ptr),
2562 input_bfd, input_section, (*parent)->address)))
2563 goto error_return;
2564 break;
2565 case bfd_reloc_dangerous:
2566 BFD_ASSERT (error_message != (char *) NULL);
2567 if (!((*link_info->callbacks->reloc_dangerous)
2568 (link_info, error_message, input_bfd, input_section,
2569 (*parent)->address)))
2570 goto error_return;
2571 break;
2572 case bfd_reloc_overflow:
2573 if (!((*link_info->callbacks->reloc_overflow)
2574 (link_info, bfd_asymbol_name (*(*parent)->sym_ptr_ptr),
2575 (*parent)->howto->name, (*parent)->addend,
2576 input_bfd, input_section, (*parent)->address)))
2577 goto error_return;
2578 break;
2579 case bfd_reloc_outofrange:
2580 default:
2581 abort ();
2582 break;
2583 }
2584
2585 }
2586 }
2587 }
2588 if (reloc_vector != NULL)
2589 free (reloc_vector);
2590 return data;
2591
2592 error_return:
2593 if (reloc_vector != NULL)
2594 free (reloc_vector);
2595 return NULL;
2596 }
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