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61ba1cf9 ILT |
1 | // reloc.h -- relocate input files for gold -*- C++ -*- |
2 | ||
6cb15b7f ILT |
3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
4 | // Written by Ian Lance Taylor <iant@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
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 3 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., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
61ba1cf9 ILT |
23 | #ifndef GOLD_RELOC_H |
24 | #define GOLD_RELOC_H | |
25 | ||
92e059d8 ILT |
26 | #include <byteswap.h> |
27 | ||
61ba1cf9 ILT |
28 | #include "workqueue.h" |
29 | ||
30 | namespace gold | |
31 | { | |
32 | ||
a3ad94ed | 33 | class General_options; |
f6ce93d6 | 34 | class Relobj; |
92e059d8 | 35 | class Read_relocs_data; |
a3ad94ed | 36 | class Symbol; |
ead1e424 | 37 | class Layout; |
92e059d8 | 38 | |
5a6f7e2d ILT |
39 | template<int size> |
40 | class Sized_symbol; | |
41 | ||
b8e6aad9 ILT |
42 | template<int size, bool big_endian> |
43 | class Sized_relobj; | |
44 | ||
45 | template<int size> | |
46 | class Symbol_value; | |
47 | ||
5a6f7e2d ILT |
48 | template<int sh_type, bool dynamic, int size, bool big_endian> |
49 | class Output_data_reloc; | |
50 | ||
92e059d8 ILT |
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 | |
53 | // the symbol table. | |
54 | ||
55 | class Read_relocs : public Task | |
56 | { | |
57 | public: | |
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, | |
f6ce93d6 | 61 | Layout* layout, Relobj* object, Task_token* symtab_lock, |
92e059d8 | 62 | Task_token* blocker) |
ead1e424 | 63 | : options_(options), symtab_(symtab), layout_(layout), object_(object), |
92e059d8 ILT |
64 | symtab_lock_(symtab_lock), blocker_(blocker) |
65 | { } | |
66 | ||
67 | // The standard Task methods. | |
68 | ||
69 | Is_runnable_type | |
70 | is_runnable(Workqueue*); | |
71 | ||
72 | Task_locker* | |
73 | locks(Workqueue*); | |
74 | ||
75 | void | |
76 | run(Workqueue*); | |
77 | ||
78 | private: | |
79 | const General_options& options_; | |
80 | Symbol_table* symtab_; | |
ead1e424 | 81 | Layout* layout_; |
f6ce93d6 | 82 | Relobj* object_; |
92e059d8 ILT |
83 | Task_token* symtab_lock_; |
84 | Task_token* blocker_; | |
85 | }; | |
86 | ||
87 | // Scan the relocations for an object to see if they require any | |
88 | // GOT/PLT/COPY relocations. | |
89 | ||
90 | class Scan_relocs : public Task | |
91 | { | |
92 | public: | |
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, | |
f6ce93d6 | 96 | Layout* layout, Relobj* object, Read_relocs_data* rd, |
ead1e424 ILT |
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) | |
92e059d8 ILT |
100 | { } |
101 | ||
102 | // The standard Task methods. | |
103 | ||
104 | Is_runnable_type | |
105 | is_runnable(Workqueue*); | |
106 | ||
107 | Task_locker* | |
108 | locks(Workqueue*); | |
109 | ||
110 | void | |
111 | run(Workqueue*); | |
112 | ||
113 | private: | |
114 | class Scan_relocs_locker; | |
115 | ||
116 | const General_options& options_; | |
117 | Symbol_table* symtab_; | |
ead1e424 | 118 | Layout* layout_; |
f6ce93d6 | 119 | Relobj* object_; |
92e059d8 ILT |
120 | Read_relocs_data* rd_; |
121 | Task_token* symtab_lock_; | |
122 | Task_token* blocker_; | |
123 | }; | |
124 | ||
125 | // A class to perform all the relocations for an object file. | |
126 | ||
61ba1cf9 ILT |
127 | class Relocate_task : public Task |
128 | { | |
129 | public: | |
130 | Relocate_task(const General_options& options, const Symbol_table* symtab, | |
f6ce93d6 | 131 | const Layout* layout, Relobj* object, Output_file* of, |
61ba1cf9 | 132 | Task_token* final_blocker) |
92e059d8 | 133 | : options_(options), symtab_(symtab), layout_(layout), object_(object), |
61ba1cf9 ILT |
134 | of_(of), final_blocker_(final_blocker) |
135 | { } | |
136 | ||
137 | // The standard Task methods. | |
138 | ||
139 | Is_runnable_type | |
140 | is_runnable(Workqueue*); | |
141 | ||
142 | Task_locker* | |
143 | locks(Workqueue*); | |
144 | ||
145 | void | |
146 | run(Workqueue*); | |
147 | ||
148 | private: | |
149 | class Relocate_locker; | |
150 | ||
151 | const General_options& options_; | |
152 | const Symbol_table* symtab_; | |
92e059d8 | 153 | const Layout* layout_; |
f6ce93d6 | 154 | Relobj* object_; |
61ba1cf9 ILT |
155 | Output_file* of_; |
156 | Task_token* final_blocker_; | |
157 | }; | |
158 | ||
92e059d8 ILT |
159 | // Standard relocation routines which are used on many targets. Here |
160 | // SIZE and BIG_ENDIAN refer to the target, not the relocation type. | |
161 | ||
162 | template<int size, bool big_endian> | |
163 | class Relocate_functions | |
164 | { | |
165 | private: | |
166 | // Do a simple relocation with the addend in the section contents. | |
167 | // VALSIZE is the size of the value. | |
168 | template<int valsize> | |
169 | static inline void | |
f6ce93d6 ILT |
170 | rel(unsigned char* view, |
171 | typename elfcpp::Swap<valsize, big_endian>::Valtype value) | |
92e059d8 | 172 | { |
f6ce93d6 | 173 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; |
92e059d8 | 174 | Valtype* wv = reinterpret_cast<Valtype*>(view); |
f6ce93d6 ILT |
175 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); |
176 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value); | |
92e059d8 ILT |
177 | } |
178 | ||
b8e6aad9 ILT |
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 | |
181 | // relocate. | |
182 | template<int valsize> | |
183 | static inline void | |
184 | rel(unsigned char* view, | |
185 | const Sized_relobj<size, big_endian>* object, | |
186 | const Symbol_value<size>* psymval) | |
187 | { | |
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); | |
193 | } | |
194 | ||
dfbba8f4 ILT |
195 | // Like rel(), but sign-extends the value to SIZE. |
196 | template<int valsize> | |
197 | static inline void | |
198 | signedrel(unsigned char* view, | |
199 | const Sized_relobj<size, big_endian>* object, | |
200 | const Symbol_value<size>* psymval) | |
201 | { | |
202 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; | |
203 | typedef typename elfcpp::Swap<size, big_endian>::Valtype Sizetype; | |
204 | Valtype* wv = reinterpret_cast<Valtype*>(view); | |
205 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); | |
206 | // Fancy formula to sign-extend x to size. | |
207 | const Sizetype mask = 1U << (sizeof(valsize) * 8 - 1); | |
208 | Sizetype sign_extended_x = x; | |
209 | sign_extended_x = (sign_extended_x ^ mask) - mask; | |
210 | x = psymval->value(object, sign_extended_x); | |
211 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x); | |
212 | } | |
213 | ||
92e059d8 ILT |
214 | // Do a simple PC relative relocation with the addend in the section |
215 | // contents. VALSIZE is the size of the value. | |
216 | template<int valsize> | |
217 | static inline void | |
f6ce93d6 ILT |
218 | pcrel(unsigned char* view, |
219 | typename elfcpp::Swap<valsize, big_endian>::Valtype value, | |
92e059d8 ILT |
220 | typename elfcpp::Elf_types<size>::Elf_Addr address) |
221 | { | |
f6ce93d6 | 222 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; |
92e059d8 | 223 | Valtype* wv = reinterpret_cast<Valtype*>(view); |
f6ce93d6 ILT |
224 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); |
225 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address); | |
92e059d8 ILT |
226 | } |
227 | ||
b8e6aad9 ILT |
228 | // Do a simple PC relative relocation with a Symbol_value with the |
229 | // addend in the section contents. VALSIZE is the size of the | |
230 | // value. | |
231 | template<int valsize> | |
232 | static inline void | |
233 | pcrel(unsigned char* view, | |
234 | const Sized_relobj<size, big_endian>* object, | |
235 | const Symbol_value<size>* psymval, | |
236 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
237 | { | |
238 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; | |
239 | Valtype* wv = reinterpret_cast<Valtype*>(view); | |
240 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); | |
241 | x = psymval->value(object, x); | |
242 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address); | |
243 | } | |
244 | ||
92e059d8 ILT |
245 | typedef Relocate_functions<size, big_endian> This; |
246 | ||
247 | public: | |
b8e6aad9 ILT |
248 | // Do a simple 8-bit REL relocation with the addend in the section |
249 | // contents. | |
92e059d8 ILT |
250 | static inline void |
251 | rel8(unsigned char* view, unsigned char value) | |
b8e6aad9 ILT |
252 | { This::template rel<8>(view, value); } |
253 | ||
254 | static inline void | |
255 | rel8(unsigned char* view, | |
256 | const Sized_relobj<size, big_endian>* object, | |
257 | const Symbol_value<size>* psymval) | |
258 | { This::template rel<8>(view, object, psymval); } | |
92e059d8 | 259 | |
dfbba8f4 ILT |
260 | // Do an 8-bit REL relocation, sign extending the addend to SIZE. |
261 | static inline void | |
262 | rel8s(unsigned char* view, | |
263 | const Sized_relobj<size, big_endian>* object, | |
264 | const Symbol_value<size>* psymval) | |
265 | { This::template signedrel<8>(view, object, psymval); } | |
266 | ||
92e059d8 | 267 | // Do a simple 8-bit PC relative relocation with the addend in the |
b8e6aad9 | 268 | // section contents. |
92e059d8 ILT |
269 | static inline void |
270 | pcrel8(unsigned char* view, unsigned char value, | |
271 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
272 | { This::template pcrel<8>(view, value, address); } |
273 | ||
274 | static inline void | |
275 | pcrel8(unsigned char* view, | |
276 | const Sized_relobj<size, big_endian>* object, | |
277 | const Symbol_value<size>* psymval, | |
278 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
279 | { This::template pcrel<8>(view, object, psymval, address); } | |
92e059d8 | 280 | |
b8e6aad9 ILT |
281 | // Do a simple 16-bit REL relocation with the addend in the section |
282 | // contents. | |
92e059d8 ILT |
283 | static inline void |
284 | rel16(unsigned char* view, elfcpp::Elf_Half value) | |
b8e6aad9 ILT |
285 | { This::template rel<16>(view, value); } |
286 | ||
287 | static inline void | |
288 | rel16(unsigned char* view, | |
289 | const Sized_relobj<size, big_endian>* object, | |
290 | const Symbol_value<size>* psymval) | |
291 | { This::template rel<16>(view, object, psymval); } | |
92e059d8 | 292 | |
dfbba8f4 ILT |
293 | // Do a 16-bit REL relocation, sign extending the addend to SIZE. |
294 | static inline void | |
295 | rel16s(unsigned char* view, | |
296 | const Sized_relobj<size, big_endian>* object, | |
297 | const Symbol_value<size>* psymval) | |
298 | { This::template signedrel<16>(view, object, psymval); } | |
299 | ||
92e059d8 | 300 | // Do a simple 32-bit PC relative REL relocation with the addend in |
b8e6aad9 | 301 | // the section contents. |
92e059d8 ILT |
302 | static inline void |
303 | pcrel16(unsigned char* view, elfcpp::Elf_Word value, | |
304 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
305 | { This::template pcrel<16>(view, value, address); } |
306 | ||
307 | static inline void | |
308 | pcrel16(unsigned char* view, | |
309 | const Sized_relobj<size, big_endian>* object, | |
310 | const Symbol_value<size>* psymval, | |
311 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
312 | { This::template pcrel<16>(view, object, psymval, address); } | |
92e059d8 ILT |
313 | |
314 | // Do a simple 32-bit REL relocation with the addend in the section | |
315 | // contents. | |
316 | static inline void | |
317 | rel32(unsigned char* view, elfcpp::Elf_Word value) | |
b8e6aad9 ILT |
318 | { This::template rel<32>(view, value); } |
319 | ||
320 | static inline void | |
321 | rel32(unsigned char* view, | |
322 | const Sized_relobj<size, big_endian>* object, | |
323 | const Symbol_value<size>* psymval) | |
324 | { This::template rel<32>(view, object, psymval); } | |
92e059d8 | 325 | |
dfbba8f4 ILT |
326 | // Do a 32-bit REL relocation, sign extending the addend to SIZE. |
327 | static inline void | |
328 | rel32s(unsigned char* view, | |
329 | const Sized_relobj<size, big_endian>* object, | |
330 | const Symbol_value<size>* psymval) | |
331 | { This::template signedrel<32>(view, object, psymval); } | |
332 | ||
92e059d8 ILT |
333 | // Do a simple 32-bit PC relative REL relocation with the addend in |
334 | // the section contents. | |
335 | static inline void | |
336 | pcrel32(unsigned char* view, elfcpp::Elf_Word value, | |
337 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
338 | { This::template pcrel<32>(view, value, address); } |
339 | ||
340 | static inline void | |
341 | pcrel32(unsigned char* view, | |
342 | const Sized_relobj<size, big_endian>* object, | |
343 | const Symbol_value<size>* psymval, | |
344 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
345 | { This::template pcrel<32>(view, object, psymval, address); } | |
92e059d8 ILT |
346 | |
347 | // Do a simple 64-bit REL relocation with the addend in the section | |
348 | // contents. | |
349 | static inline void | |
f6ce93d6 | 350 | rel64(unsigned char* view, elfcpp::Elf_Xword value) |
b8e6aad9 ILT |
351 | { This::template rel<64>(view, value); } |
352 | ||
353 | static inline void | |
354 | rel64(unsigned char* view, | |
355 | const Sized_relobj<size, big_endian>* object, | |
356 | const Symbol_value<size>* psymval) | |
357 | { This::template rel<64>(view, object, psymval); } | |
92e059d8 ILT |
358 | |
359 | // Do a simple 64-bit PC relative REL relocation with the addend in | |
360 | // the section contents. | |
361 | static inline void | |
f6ce93d6 | 362 | pcrel64(unsigned char* view, elfcpp::Elf_Xword value, |
92e059d8 | 363 | typename elfcpp::Elf_types<size>::Elf_Addr address) |
b8e6aad9 ILT |
364 | { This::template pcrel<64>(view, value, address); } |
365 | ||
366 | static inline void | |
367 | pcrel64(unsigned char* view, | |
368 | const Sized_relobj<size, big_endian>* object, | |
369 | const Symbol_value<size>* psymval, | |
370 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
371 | { This::template pcrel<64>(view, object, psymval, address); } | |
5a6f7e2d ILT |
372 | }; |
373 | ||
374 | // We try to avoid COPY relocations when possible. A COPY relocation | |
375 | // may be required when an executable refers to a variable defined in | |
376 | // a shared library. COPY relocations are problematic because they | |
377 | // tie the executable to the exact size of the variable in the shared | |
378 | // library. We can avoid them if all the references to the variable | |
379 | // are in a writeable section. In that case we can simply use dynamic | |
380 | // relocations. However, when scanning relocs, we don't know when we | |
381 | // see the relocation whether we will be forced to use a COPY | |
382 | // relocation or not. So we have to save the relocation during the | |
383 | // reloc scanning, and then emit it as a dynamic relocation if | |
384 | // necessary. This class implements that. It is used by the target | |
385 | // specific code. | |
386 | ||
387 | template<int size, bool big_endian> | |
388 | class Copy_relocs | |
389 | { | |
390 | public: | |
391 | Copy_relocs() | |
392 | : entries_() | |
393 | { } | |
a3ad94ed ILT |
394 | |
395 | // Return whether we need a COPY reloc for a reloc against GSYM, | |
396 | // which is being applied to section SHNDX in OBJECT. | |
397 | static bool | |
398 | need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx, | |
5a6f7e2d ILT |
399 | Sized_symbol<size>* gsym); |
400 | ||
401 | // Save a Rel against SYM for possible emission later. SHNDX is the | |
402 | // index of the section to which the reloc is being applied. | |
403 | void | |
404 | save(Symbol* sym, Relobj*, unsigned int shndx, | |
405 | const elfcpp::Rel<size, big_endian>&); | |
406 | ||
407 | // Save a Rela against SYM for possible emission later. | |
408 | void | |
409 | save(Symbol* sym, Relobj*, unsigned int shndx, | |
410 | const elfcpp::Rela<size, big_endian>&); | |
411 | ||
412 | // Return whether there are any relocs to emit. This also discards | |
413 | // entries which need not be emitted. | |
414 | bool | |
415 | any_to_emit(); | |
416 | ||
417 | // Emit relocs for each symbol which did not get a COPY reloc (i.e., | |
418 | // is still defined in the dynamic object). | |
419 | template<int sh_type> | |
420 | void | |
421 | emit(Output_data_reloc<sh_type, true, size, big_endian>*); | |
422 | ||
423 | private: | |
424 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; | |
425 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend; | |
426 | ||
427 | // This POD class holds the entries we are saving. | |
428 | class Copy_reloc_entry | |
429 | { | |
430 | public: | |
431 | Copy_reloc_entry(Symbol* sym, unsigned int reloc_type, | |
432 | Relobj* relobj, unsigned int shndx, | |
433 | Address address, Addend addend) | |
434 | : sym_(sym), reloc_type_(reloc_type), relobj_(relobj), | |
435 | shndx_(shndx), address_(address), addend_(addend) | |
436 | { } | |
437 | ||
438 | // Return whether we should emit this reloc. If we should not | |
439 | // emit, we clear it. | |
440 | bool | |
441 | should_emit(); | |
442 | ||
443 | // Emit this reloc. | |
444 | ||
445 | void | |
446 | emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*); | |
447 | ||
448 | void | |
449 | emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*); | |
450 | ||
451 | private: | |
452 | Symbol* sym_; | |
453 | unsigned int reloc_type_; | |
454 | Relobj* relobj_; | |
455 | unsigned int shndx_; | |
456 | Address address_; | |
457 | Addend addend_; | |
458 | }; | |
459 | ||
460 | // A list of relocs to be saved. | |
461 | typedef std::vector<Copy_reloc_entry> Copy_reloc_entries; | |
462 | ||
463 | // The list of relocs we are saving. | |
464 | Copy_reloc_entries entries_; | |
92e059d8 ILT |
465 | }; |
466 | ||
61ba1cf9 ILT |
467 | } // End namespace gold. |
468 | ||
469 | #endif // !defined(GOLD_RELOC_H) |