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<valsize, big_endian>::Signed_valtype
233 typedef typename elfcpp::Swap<size, big_endian>::Valtype Sizetype;
234 typedef typename elfcpp::Swap<size, big_endian>::Signed_valtype
236 Valtype* wv = reinterpret_cast<Valtype*>(view);
237 Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
239 // Sign extend the value.
240 Signed_valtype signed_x = static_cast<Signed_valtype>(x);
241 Signed_sizetype signed_extended_x = static_cast<Signed_sizetype>(signed_x);
242 Sizetype unsigned_extended_x = static_cast<Sizetype>(signed_extended_x);
244 x = psymval->value(object, unsigned_extended_x);
245 elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
248 // Do a simple PC relative relocation with the addend in the section
249 // contents. VALSIZE is the size of the value.
250 template<int valsize>
252 pcrel(unsigned char* view,
253 typename elfcpp::Swap<valsize, big_endian>::Valtype value,
254 typename elfcpp::Elf_types<size>::Elf_Addr address)
256 typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
257 Valtype* wv = reinterpret_cast<Valtype*>(view);
258 Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
259 elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address);
262 // Do a simple PC relative relocation with a Symbol_value with the
263 // addend in the section contents. VALSIZE is the size of the
265 template<int valsize>
267 pcrel(unsigned char* view,
268 const Sized_relobj<size, big_endian>* object,
269 const Symbol_value<size>* psymval,
270 typename elfcpp::Elf_types<size>::Elf_Addr address)
272 typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
273 Valtype* wv = reinterpret_cast<Valtype*>(view);
274 Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
275 x = psymval->value(object, x);
276 elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
279 // Do a simple PC relative relocation with the addend in the
280 // relocation. VALSIZE is the size of the value.
281 template<int valsize>
283 pcrela(unsigned char* view,
284 typename elfcpp::Swap<valsize, big_endian>::Valtype value,
285 typename elfcpp::Swap<valsize, big_endian>::Valtype addend,
286 typename elfcpp::Elf_types<size>::Elf_Addr address)
288 typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
289 Valtype* wv = reinterpret_cast<Valtype*>(view);
290 elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend - address);
293 // Do a simple PC relative relocation with a Symbol_value with the
294 // addend in the relocation. VALSIZE is the size of the value.
295 template<int valsize>
297 pcrela(unsigned char* view,
298 const Sized_relobj<size, big_endian>* object,
299 const Symbol_value<size>* psymval,
300 typename elfcpp::Swap<valsize, big_endian>::Valtype addend,
301 typename elfcpp::Elf_types<size>::Elf_Addr address)
303 typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
304 Valtype* wv = reinterpret_cast<Valtype*>(view);
305 Valtype x = psymval->value(object, addend);
306 elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
309 typedef Relocate_functions<size, big_endian> This;
312 // Do a simple 8-bit REL relocation with the addend in the section
315 rel8(unsigned char* view, unsigned char value)
316 { This::template rel<8>(view, value); }
319 rel8(unsigned char* view,
320 const Sized_relobj<size, big_endian>* object,
321 const Symbol_value<size>* psymval)
322 { This::template rel<8>(view, object, psymval); }
324 // Do an 8-bit RELA relocation with the addend in the relocation.
326 rela8(unsigned char* view, unsigned char value, unsigned char addend)
327 { This::template rela<8>(view, value, addend); }
330 rela8(unsigned char* view,
331 const Sized_relobj<size, big_endian>* object,
332 const Symbol_value<size>* psymval,
333 unsigned char addend)
334 { This::template rela<8>(view, object, psymval, addend); }
336 // Do an 8-bit REL relocation, sign extending the addend to SIZE.
338 rel8s(unsigned char* view,
339 const Sized_relobj<size, big_endian>* object,
340 const Symbol_value<size>* psymval)
341 { This::template signedrel<8>(view, object, psymval); }
343 // Do a simple 8-bit PC relative relocation with the addend in the
346 pcrel8(unsigned char* view, unsigned char value,
347 typename elfcpp::Elf_types<size>::Elf_Addr address)
348 { This::template pcrel<8>(view, value, address); }
351 pcrel8(unsigned char* view,
352 const Sized_relobj<size, big_endian>* object,
353 const Symbol_value<size>* psymval,
354 typename elfcpp::Elf_types<size>::Elf_Addr address)
355 { This::template pcrel<8>(view, object, psymval, address); }
357 // Do a simple 8-bit PC relative RELA relocation with the addend in
360 pcrela8(unsigned char* view, unsigned char value, unsigned char addend,
361 typename elfcpp::Elf_types<size>::Elf_Addr address)
362 { This::template pcrela<8>(view, value, addend, address); }
365 pcrela8(unsigned char* view,
366 const Sized_relobj<size, big_endian>* object,
367 const Symbol_value<size>* psymval,
368 unsigned char addend,
369 typename elfcpp::Elf_types<size>::Elf_Addr address)
370 { This::template pcrela<8>(view, object, psymval, addend, address); }
372 // Do a simple 16-bit REL relocation with the addend in the section
375 rel16(unsigned char* view, elfcpp::Elf_Half value)
376 { This::template rel<16>(view, value); }
379 rel16(unsigned char* view,
380 const Sized_relobj<size, big_endian>* object,
381 const Symbol_value<size>* psymval)
382 { This::template rel<16>(view, object, psymval); }
384 // Do an 16-bit RELA relocation with the addend in the relocation.
386 rela16(unsigned char* view, elfcpp::Elf_Half value, elfcpp::Elf_Half addend)
387 { This::template rela<16>(view, value, addend); }
390 rela16(unsigned char* view,
391 const Sized_relobj<size, big_endian>* object,
392 const Symbol_value<size>* psymval,
393 elfcpp::Elf_Half addend)
394 { This::template rela<16>(view, object, psymval, addend); }
396 // Do a 16-bit REL relocation, sign extending the addend to SIZE.
398 rel16s(unsigned char* view,
399 const Sized_relobj<size, big_endian>* object,
400 const Symbol_value<size>* psymval)
401 { This::template signedrel<16>(view, object, psymval); }
403 // Do a simple 16-bit PC relative REL relocation with the addend in
404 // the section contents.
406 pcrel16(unsigned char* view, elfcpp::Elf_Half value,
407 typename elfcpp::Elf_types<size>::Elf_Addr address)
408 { This::template pcrel<16>(view, value, address); }
411 pcrel16(unsigned char* view,
412 const Sized_relobj<size, big_endian>* object,
413 const Symbol_value<size>* psymval,
414 typename elfcpp::Elf_types<size>::Elf_Addr address)
415 { This::template pcrel<16>(view, object, psymval, address); }
417 // Do a simple 16-bit PC relative RELA relocation with the addend in
420 pcrela16(unsigned char* view, elfcpp::Elf_Half value,
421 elfcpp::Elf_Half addend,
422 typename elfcpp::Elf_types<size>::Elf_Addr address)
423 { This::template pcrela<16>(view, value, addend, address); }
426 pcrela16(unsigned char* view,
427 const Sized_relobj<size, big_endian>* object,
428 const Symbol_value<size>* psymval,
429 elfcpp::Elf_Half addend,
430 typename elfcpp::Elf_types<size>::Elf_Addr address)
431 { This::template pcrela<16>(view, object, psymval, addend, address); }
433 // Do a simple 32-bit REL relocation with the addend in the section
436 rel32(unsigned char* view, elfcpp::Elf_Word value)
437 { This::template rel<32>(view, value); }
440 rel32(unsigned char* view,
441 const Sized_relobj<size, big_endian>* object,
442 const Symbol_value<size>* psymval)
443 { This::template rel<32>(view, object, psymval); }
445 // Do an 32-bit RELA relocation with the addend in the relocation.
447 rela32(unsigned char* view, elfcpp::Elf_Word value, elfcpp::Elf_Word addend)
448 { This::template rela<32>(view, value, addend); }
451 rela32(unsigned char* view,
452 const Sized_relobj<size, big_endian>* object,
453 const Symbol_value<size>* psymval,
454 elfcpp::Elf_Word addend)
455 { This::template rela<32>(view, object, psymval, addend); }
457 // Do a 32-bit REL relocation, sign extending the addend to SIZE.
459 rel32s(unsigned char* view,
460 const Sized_relobj<size, big_endian>* object,
461 const Symbol_value<size>* psymval)
462 { This::template signedrel<32>(view, object, psymval); }
464 // Do a simple 32-bit PC relative REL relocation with the addend in
465 // the section contents.
467 pcrel32(unsigned char* view, elfcpp::Elf_Word value,
468 typename elfcpp::Elf_types<size>::Elf_Addr address)
469 { This::template pcrel<32>(view, value, address); }
472 pcrel32(unsigned char* view,
473 const Sized_relobj<size, big_endian>* object,
474 const Symbol_value<size>* psymval,
475 typename elfcpp::Elf_types<size>::Elf_Addr address)
476 { This::template pcrel<32>(view, object, psymval, address); }
478 // Do a simple 32-bit PC relative RELA relocation with the addend in
481 pcrela32(unsigned char* view, elfcpp::Elf_Word value,
482 elfcpp::Elf_Word addend,
483 typename elfcpp::Elf_types<size>::Elf_Addr address)
484 { This::template pcrela<32>(view, value, addend, address); }
487 pcrela32(unsigned char* view,
488 const Sized_relobj<size, big_endian>* object,
489 const Symbol_value<size>* psymval,
490 elfcpp::Elf_Word addend,
491 typename elfcpp::Elf_types<size>::Elf_Addr address)
492 { This::template pcrela<32>(view, object, psymval, addend, address); }
494 // Do a simple 64-bit REL relocation with the addend in the section
497 rel64(unsigned char* view, elfcpp::Elf_Xword value)
498 { This::template rel<64>(view, value); }
501 rel64(unsigned char* view,
502 const Sized_relobj<size, big_endian>* object,
503 const Symbol_value<size>* psymval)
504 { This::template rel<64>(view, object, psymval); }
506 // Do a 64-bit RELA relocation with the addend in the relocation.
508 rela64(unsigned char* view, elfcpp::Elf_Xword value,
509 elfcpp::Elf_Xword addend)
510 { This::template rela<64>(view, value, addend); }
513 rela64(unsigned char* view,
514 const Sized_relobj<size, big_endian>* object,
515 const Symbol_value<size>* psymval,
516 elfcpp::Elf_Xword addend)
517 { This::template rela<64>(view, object, psymval, addend); }
519 // Do a simple 64-bit PC relative REL relocation with the addend in
520 // the section contents.
522 pcrel64(unsigned char* view, elfcpp::Elf_Xword value,
523 typename elfcpp::Elf_types<size>::Elf_Addr address)
524 { This::template pcrel<64>(view, value, address); }
527 pcrel64(unsigned char* view,
528 const Sized_relobj<size, big_endian>* object,
529 const Symbol_value<size>* psymval,
530 typename elfcpp::Elf_types<size>::Elf_Addr address)
531 { This::template pcrel<64>(view, object, psymval, address); }
533 // Do a simple 64-bit PC relative RELA relocation with the addend in
536 pcrela64(unsigned char* view, elfcpp::Elf_Xword value,
537 elfcpp::Elf_Xword addend,
538 typename elfcpp::Elf_types<size>::Elf_Addr address)
539 { This::template pcrela<64>(view, value, addend, address); }
542 pcrela64(unsigned char* view,
543 const Sized_relobj<size, big_endian>* object,
544 const Symbol_value<size>* psymval,
545 elfcpp::Elf_Xword addend,
546 typename elfcpp::Elf_types<size>::Elf_Addr address)
547 { This::template pcrela<64>(view, object, psymval, addend, address); }
550 // We try to avoid COPY relocations when possible. A COPY relocation
551 // may be required when an executable refers to a variable defined in
552 // a shared library. COPY relocations are problematic because they
553 // tie the executable to the exact size of the variable in the shared
554 // library. We can avoid them if all the references to the variable
555 // are in a writeable section. In that case we can simply use dynamic
556 // relocations. However, when scanning relocs, we don't know when we
557 // see the relocation whether we will be forced to use a COPY
558 // relocation or not. So we have to save the relocation during the
559 // reloc scanning, and then emit it as a dynamic relocation if
560 // necessary. This class implements that. It is used by the target
563 template<int size, bool big_endian>
571 // Return whether we need a COPY reloc for a reloc against GSYM,
572 // which is being applied to section SHNDX in OBJECT.
574 need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx,
575 Sized_symbol<size>* gsym);
577 // Save a Rel against SYM for possible emission later. SHNDX is the
578 // index of the section to which the reloc is being applied.
580 save(Symbol* sym, Relobj*, unsigned int shndx,
581 const elfcpp::Rel<size, big_endian>&);
583 // Save a Rela against SYM for possible emission later.
585 save(Symbol* sym, Relobj*, unsigned int shndx,
586 const elfcpp::Rela<size, big_endian>&);
588 // Return whether there are any relocs to emit. This also discards
589 // entries which need not be emitted.
593 // Emit relocs for each symbol which did not get a COPY reloc (i.e.,
594 // is still defined in the dynamic object).
595 template<int sh_type>
597 emit(Output_data_reloc<sh_type, true, size, big_endian>*);
600 typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
601 typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
603 // This POD class holds the entries we are saving.
604 class Copy_reloc_entry
607 Copy_reloc_entry(Symbol* sym, unsigned int reloc_type,
608 Relobj* relobj, unsigned int shndx,
609 Address address, Addend addend)
610 : sym_(sym), reloc_type_(reloc_type), relobj_(relobj),
611 shndx_(shndx), address_(address), addend_(addend)
614 // Return whether we should emit this reloc. If we should not
615 // emit, we clear it.
622 emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*);
625 emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*);
629 unsigned int reloc_type_;
636 // A list of relocs to be saved.
637 typedef std::vector<Copy_reloc_entry> Copy_reloc_entries;
639 // The list of relocs we are saving.
640 Copy_reloc_entries entries_;
643 } // End namespace gold.
645 #endif // !defined(GOLD_RELOC_H)