1 // reloc.h -- relocate input files for gold -*- C++ -*-
3 // Copyright 2006, 2007 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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 3 of the License, or
11 // (at your option) any later version.
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.
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., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
28 #include "workqueue.h"
33 class General_options
;
35 class Read_relocs_data
;
42 template<int size
, bool big_endian
>
48 template<int sh_type
, bool dynamic
, int size
, bool big_endian
>
49 class Output_data_reloc
;
51 // A class to read the relocations for an object file, and then queue
52 // up a task to see if they require any GOT/PLT/COPY relocations in
55 class Read_relocs
: public Task
58 // SYMTAB_LOCK is used to lock the symbol table. BLOCKER should be
59 // unblocked when the Scan_relocs task completes.
60 Read_relocs(const General_options
& options
, Symbol_table
* symtab
,
61 Layout
* layout
, Relobj
* object
, Task_token
* symtab_lock
,
63 : options_(options
), symtab_(symtab
), layout_(layout
), object_(object
),
64 symtab_lock_(symtab_lock
), blocker_(blocker
)
67 // The standard Task methods.
70 is_runnable(Workqueue
*);
79 const General_options
& options_
;
80 Symbol_table
* symtab_
;
83 Task_token
* symtab_lock_
;
87 // Scan the relocations for an object to see if they require any
88 // GOT/PLT/COPY relocations.
90 class Scan_relocs
: public Task
93 // SYMTAB_LOCK is used to lock the symbol table. BLOCKER should be
94 // unblocked when the task completes.
95 Scan_relocs(const General_options
& options
, Symbol_table
* symtab
,
96 Layout
* layout
, Relobj
* object
, Read_relocs_data
* rd
,
97 Task_token
* symtab_lock
, Task_token
* blocker
)
98 : options_(options
), symtab_(symtab
), layout_(layout
), object_(object
),
99 rd_(rd
), symtab_lock_(symtab_lock
), blocker_(blocker
)
102 // The standard Task methods.
105 is_runnable(Workqueue
*);
114 class Scan_relocs_locker
;
116 const General_options
& options_
;
117 Symbol_table
* symtab_
;
120 Read_relocs_data
* rd_
;
121 Task_token
* symtab_lock_
;
122 Task_token
* blocker_
;
125 // A class to perform all the relocations for an object file.
127 class Relocate_task
: public Task
130 Relocate_task(const General_options
& options
, const Symbol_table
* symtab
,
131 const Layout
* layout
, Relobj
* object
, Output_file
* of
,
132 Task_token
* final_blocker
)
133 : options_(options
), symtab_(symtab
), layout_(layout
), object_(object
),
134 of_(of
), final_blocker_(final_blocker
)
137 // The standard Task methods.
140 is_runnable(Workqueue
*);
149 class Relocate_locker
;
151 const General_options
& options_
;
152 const Symbol_table
* symtab_
;
153 const Layout
* layout_
;
156 Task_token
* final_blocker_
;
159 // Standard relocation routines which are used on many targets. Here
160 // SIZE and BIG_ENDIAN refer to the target, not the relocation type.
162 template<int size
, bool big_endian
>
163 class Relocate_functions
166 // Do a simple relocation with the addend in the section contents.
167 // VALSIZE is the size of the value.
168 template<int valsize
>
170 rel(unsigned char* view
,
171 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype value
)
173 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
174 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
175 Valtype x
= elfcpp::Swap
<valsize
, big_endian
>::readval(wv
);
176 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
+ value
);
179 // Do a simple relocation using a Symbol_value with the addend in
180 // the section contents. VALSIZE is the size of the value to
182 template<int valsize
>
184 rel(unsigned char* view
,
185 const Sized_relobj
<size
, big_endian
>* object
,
186 const Symbol_value
<size
>* psymval
)
188 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
189 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
190 Valtype x
= elfcpp::Swap
<valsize
, big_endian
>::readval(wv
);
191 x
= psymval
->value(object
, x
);
192 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
);
195 // Do a simple relocation with the addend in the relocation.
196 // VALSIZE is the size of the value.
197 template<int valsize
>
199 rela(unsigned char* view
,
200 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype value
,
201 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype addend
)
203 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
204 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
205 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, value
+ addend
);
208 // Do a simple relocation using a symbol value with the addend in
209 // the relocation. VALSIZE is the size of the value.
210 template<int valsize
>
212 rela(unsigned char* view
,
213 const Sized_relobj
<size
, big_endian
>* object
,
214 const Symbol_value
<size
>* psymval
,
215 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype addend
)
217 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
218 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
219 Valtype x
= psymval
->value(object
, addend
);
220 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
);
223 // Like rel(), but sign-extends the value to SIZE.
224 template<int valsize
>
226 signedrel(unsigned char* view
,
227 const Sized_relobj
<size
, big_endian
>* object
,
228 const Symbol_value
<size
>* psymval
)
230 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
231 typedef typename
elfcpp::Swap
<size
, big_endian
>::Valtype Sizetype
;
232 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
233 Valtype x
= elfcpp::Swap
<valsize
, big_endian
>::readval(wv
);
234 // Fancy formula to sign-extend x to size.
235 const Sizetype mask
= 1U << (sizeof(valsize
) * 8 - 1);
236 Sizetype sign_extended_x
= x
;
237 sign_extended_x
= (sign_extended_x
^ mask
) - mask
;
238 x
= psymval
->value(object
, sign_extended_x
);
239 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
);
242 // Do a simple PC relative relocation with the addend in the section
243 // contents. VALSIZE is the size of the value.
244 template<int valsize
>
246 pcrel(unsigned char* view
,
247 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype value
,
248 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
250 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
251 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
252 Valtype x
= elfcpp::Swap
<valsize
, big_endian
>::readval(wv
);
253 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
+ value
- address
);
256 // Do a simple PC relative relocation with a Symbol_value with the
257 // addend in the section contents. VALSIZE is the size of the
259 template<int valsize
>
261 pcrel(unsigned char* view
,
262 const Sized_relobj
<size
, big_endian
>* object
,
263 const Symbol_value
<size
>* psymval
,
264 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
266 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
267 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
268 Valtype x
= elfcpp::Swap
<valsize
, big_endian
>::readval(wv
);
269 x
= psymval
->value(object
, x
);
270 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
- address
);
273 // Do a simple PC relative relocation with the addend in the
274 // relocation. VALSIZE is the size of the value.
275 template<int valsize
>
277 pcrela(unsigned char* view
,
278 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype value
,
279 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype addend
,
280 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
282 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
283 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
284 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, value
+ addend
- address
);
287 // Do a simple PC relative relocation with a Symbol_value with the
288 // addend in the relocation. VALSIZE is the size of the value.
289 template<int valsize
>
291 pcrela(unsigned char* view
,
292 const Sized_relobj
<size
, big_endian
>* object
,
293 const Symbol_value
<size
>* psymval
,
294 typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype addend
,
295 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
297 typedef typename
elfcpp::Swap
<valsize
, big_endian
>::Valtype Valtype
;
298 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
299 Valtype x
= psymval
->value(object
, addend
);
300 elfcpp::Swap
<valsize
, big_endian
>::writeval(wv
, x
- address
);
303 typedef Relocate_functions
<size
, big_endian
> This
;
306 // Do a simple 8-bit REL relocation with the addend in the section
309 rel8(unsigned char* view
, unsigned char value
)
310 { This::template rel
<8>(view
, value
); }
313 rel8(unsigned char* view
,
314 const Sized_relobj
<size
, big_endian
>* object
,
315 const Symbol_value
<size
>* psymval
)
316 { This::template rel
<8>(view
, object
, psymval
); }
318 // Do an 8-bit RELA relocation with the addend in the relocation.
320 rel8a(unsigned char* view
, unsigned char value
, unsigned char addend
)
321 { This::template rela
<8>(view
, value
, addend
); }
324 rel8a(unsigned char* view
,
325 const Sized_relobj
<size
, big_endian
>* object
,
326 const Symbol_value
<size
>* psymval
,
327 unsigned char addend
)
328 { This::template rela
<8>(view
, object
, psymval
, addend
); }
330 // Do an 8-bit REL relocation, sign extending the addend to SIZE.
332 rel8s(unsigned char* view
,
333 const Sized_relobj
<size
, big_endian
>* object
,
334 const Symbol_value
<size
>* psymval
)
335 { This::template signedrel
<8>(view
, object
, psymval
); }
337 // Do a simple 8-bit PC relative relocation with the addend in the
340 pcrel8(unsigned char* view
, unsigned char value
,
341 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
342 { This::template pcrel
<8>(view
, value
, address
); }
345 pcrel8(unsigned char* view
,
346 const Sized_relobj
<size
, big_endian
>* object
,
347 const Symbol_value
<size
>* psymval
,
348 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
349 { This::template pcrel
<8>(view
, object
, psymval
, address
); }
351 // Do a simple 8-bit PC relative RELA relocation with the addend in
354 pcrela8(unsigned char* view
, unsigned char value
, unsigned char addend
,
355 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
356 { This::template pcrela
<8>(view
, value
, addend
, address
); }
359 pcrela8(unsigned char* view
,
360 const Sized_relobj
<size
, big_endian
>* object
,
361 const Symbol_value
<size
>* psymval
,
362 unsigned char addend
,
363 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
364 { This::template pcrela
<8>(view
, object
, psymval
, addend
, address
); }
366 // Do a simple 16-bit REL relocation with the addend in the section
369 rel16(unsigned char* view
, elfcpp::Elf_Half value
)
370 { This::template rel
<16>(view
, value
); }
373 rel16(unsigned char* view
,
374 const Sized_relobj
<size
, big_endian
>* object
,
375 const Symbol_value
<size
>* psymval
)
376 { This::template rel
<16>(view
, object
, psymval
); }
378 // Do an 16-bit RELA relocation with the addend in the relocation.
380 rela16(unsigned char* view
, elfcpp::Elf_Half value
, elfcpp::Elf_Half addend
)
381 { This::template rela
<16>(view
, value
, addend
); }
384 rela16(unsigned char* view
,
385 const Sized_relobj
<size
, big_endian
>* object
,
386 const Symbol_value
<size
>* psymval
,
387 elfcpp::Elf_Half addend
)
388 { This::template rela
<16>(view
, object
, psymval
, addend
); }
390 // Do a 16-bit REL relocation, sign extending the addend to SIZE.
392 rel16s(unsigned char* view
,
393 const Sized_relobj
<size
, big_endian
>* object
,
394 const Symbol_value
<size
>* psymval
)
395 { This::template signedrel
<16>(view
, object
, psymval
); }
397 // Do a simple 16-bit PC relative REL relocation with the addend in
398 // the section contents.
400 pcrel16(unsigned char* view
, elfcpp::Elf_Half value
,
401 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
402 { This::template pcrel
<16>(view
, value
, address
); }
405 pcrel16(unsigned char* view
,
406 const Sized_relobj
<size
, big_endian
>* object
,
407 const Symbol_value
<size
>* psymval
,
408 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
409 { This::template pcrel
<16>(view
, object
, psymval
, address
); }
411 // Do a simple 16-bit PC relative RELA relocation with the addend in
414 pcrela16(unsigned char* view
, elfcpp::Elf_Half value
,
415 elfcpp::Elf_Half addend
,
416 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
417 { This::template pcrela
<16>(view
, value
, addend
, address
); }
420 pcrela16(unsigned char* view
,
421 const Sized_relobj
<size
, big_endian
>* object
,
422 const Symbol_value
<size
>* psymval
,
423 elfcpp::Elf_Half addend
,
424 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
425 { This::template pcrela
<16>(view
, object
, psymval
, addend
, address
); }
427 // Do a simple 32-bit REL relocation with the addend in the section
430 rel32(unsigned char* view
, elfcpp::Elf_Word value
)
431 { This::template rel
<32>(view
, value
); }
434 rel32(unsigned char* view
,
435 const Sized_relobj
<size
, big_endian
>* object
,
436 const Symbol_value
<size
>* psymval
)
437 { This::template rel
<32>(view
, object
, psymval
); }
439 // Do an 32-bit RELA relocation with the addend in the relocation.
441 rela32(unsigned char* view
, elfcpp::Elf_Word value
, elfcpp::Elf_Word addend
)
442 { This::template rela
<32>(view
, value
, addend
); }
445 rela32(unsigned char* view
,
446 const Sized_relobj
<size
, big_endian
>* object
,
447 const Symbol_value
<size
>* psymval
,
448 elfcpp::Elf_Word addend
)
449 { This::template rela
<32>(view
, object
, psymval
, addend
); }
451 // Do a 32-bit REL relocation, sign extending the addend to SIZE.
453 rel32s(unsigned char* view
,
454 const Sized_relobj
<size
, big_endian
>* object
,
455 const Symbol_value
<size
>* psymval
)
456 { This::template signedrel
<32>(view
, object
, psymval
); }
458 // Do a simple 32-bit PC relative REL relocation with the addend in
459 // the section contents.
461 pcrel32(unsigned char* view
, elfcpp::Elf_Word value
,
462 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
463 { This::template pcrel
<32>(view
, value
, address
); }
466 pcrel32(unsigned char* view
,
467 const Sized_relobj
<size
, big_endian
>* object
,
468 const Symbol_value
<size
>* psymval
,
469 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
470 { This::template pcrel
<32>(view
, object
, psymval
, address
); }
472 // Do a simple 32-bit PC relative RELA relocation with the addend in
475 pcrela32(unsigned char* view
, elfcpp::Elf_Word value
,
476 elfcpp::Elf_Word addend
,
477 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
478 { This::template pcrela
<32>(view
, value
, addend
, address
); }
481 pcrela32(unsigned char* view
,
482 const Sized_relobj
<size
, big_endian
>* object
,
483 const Symbol_value
<size
>* psymval
,
484 elfcpp::Elf_Word addend
,
485 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
486 { This::template pcrela
<32>(view
, object
, psymval
, addend
, address
); }
488 // Do a simple 64-bit REL relocation with the addend in the section
491 rel64(unsigned char* view
, elfcpp::Elf_Xword value
)
492 { This::template rel
<64>(view
, value
); }
495 rel64(unsigned char* view
,
496 const Sized_relobj
<size
, big_endian
>* object
,
497 const Symbol_value
<size
>* psymval
)
498 { This::template rel
<64>(view
, object
, psymval
); }
500 // Do a 64-bit RELA relocation with the addend in the relocation.
502 rela64(unsigned char* view
, elfcpp::Elf_Xword value
,
503 elfcpp::Elf_Xword addend
)
504 { This::template rela
<64>(view
, value
, addend
); }
507 rela64(unsigned char* view
,
508 const Sized_relobj
<size
, big_endian
>* object
,
509 const Symbol_value
<size
>* psymval
,
510 elfcpp::Elf_Xword addend
)
511 { This::template rela
<64>(view
, object
, psymval
, addend
); }
513 // Do a simple 64-bit PC relative REL relocation with the addend in
514 // the section contents.
516 pcrel64(unsigned char* view
, elfcpp::Elf_Xword value
,
517 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
518 { This::template pcrel
<64>(view
, value
, address
); }
521 pcrel64(unsigned char* view
,
522 const Sized_relobj
<size
, big_endian
>* object
,
523 const Symbol_value
<size
>* psymval
,
524 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
525 { This::template pcrel
<64>(view
, object
, psymval
, address
); }
527 // Do a simple 64-bit PC relative RELA relocation with the addend in
530 pcrela64(unsigned char* view
, elfcpp::Elf_Xword value
,
531 elfcpp::Elf_Xword addend
,
532 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
533 { This::template pcrela
<64>(view
, value
, addend
, address
); }
536 pcrela64(unsigned char* view
,
537 const Sized_relobj
<size
, big_endian
>* object
,
538 const Symbol_value
<size
>* psymval
,
539 elfcpp::Elf_Xword addend
,
540 typename
elfcpp::Elf_types
<size
>::Elf_Addr address
)
541 { This::template pcrela
<64>(view
, object
, psymval
, addend
, address
); }
544 // We try to avoid COPY relocations when possible. A COPY relocation
545 // may be required when an executable refers to a variable defined in
546 // a shared library. COPY relocations are problematic because they
547 // tie the executable to the exact size of the variable in the shared
548 // library. We can avoid them if all the references to the variable
549 // are in a writeable section. In that case we can simply use dynamic
550 // relocations. However, when scanning relocs, we don't know when we
551 // see the relocation whether we will be forced to use a COPY
552 // relocation or not. So we have to save the relocation during the
553 // reloc scanning, and then emit it as a dynamic relocation if
554 // necessary. This class implements that. It is used by the target
557 template<int size
, bool big_endian
>
565 // Return whether we need a COPY reloc for a reloc against GSYM,
566 // which is being applied to section SHNDX in OBJECT.
568 need_copy_reloc(const General_options
*, Relobj
* object
, unsigned int shndx
,
569 Sized_symbol
<size
>* gsym
);
571 // Save a Rel against SYM for possible emission later. SHNDX is the
572 // index of the section to which the reloc is being applied.
574 save(Symbol
* sym
, Relobj
*, unsigned int shndx
,
575 const elfcpp::Rel
<size
, big_endian
>&);
577 // Save a Rela against SYM for possible emission later.
579 save(Symbol
* sym
, Relobj
*, unsigned int shndx
,
580 const elfcpp::Rela
<size
, big_endian
>&);
582 // Return whether there are any relocs to emit. This also discards
583 // entries which need not be emitted.
587 // Emit relocs for each symbol which did not get a COPY reloc (i.e.,
588 // is still defined in the dynamic object).
589 template<int sh_type
>
591 emit(Output_data_reloc
<sh_type
, true, size
, big_endian
>*);
594 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Address
;
595 typedef typename
elfcpp::Elf_types
<size
>::Elf_Addr Addend
;
597 // This POD class holds the entries we are saving.
598 class Copy_reloc_entry
601 Copy_reloc_entry(Symbol
* sym
, unsigned int reloc_type
,
602 Relobj
* relobj
, unsigned int shndx
,
603 Address address
, Addend addend
)
604 : sym_(sym
), reloc_type_(reloc_type
), relobj_(relobj
),
605 shndx_(shndx
), address_(address
), addend_(addend
)
608 // Return whether we should emit this reloc. If we should not
609 // emit, we clear it.
616 emit(Output_data_reloc
<elfcpp::SHT_REL
, true, size
, big_endian
>*);
619 emit(Output_data_reloc
<elfcpp::SHT_RELA
, true, size
, big_endian
>*);
623 unsigned int reloc_type_
;
630 // A list of relocs to be saved.
631 typedef std::vector
<Copy_reloc_entry
> Copy_reloc_entries
;
633 // The list of relocs we are saving.
634 Copy_reloc_entries entries_
;
637 } // End namespace gold.
639 #endif // !defined(GOLD_RELOC_H)