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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 | ||
92e059d8 ILT |
195 | // Do a simple PC relative relocation with the addend in the section |
196 | // contents. VALSIZE is the size of the value. | |
197 | template<int valsize> | |
198 | static inline void | |
f6ce93d6 ILT |
199 | pcrel(unsigned char* view, |
200 | typename elfcpp::Swap<valsize, big_endian>::Valtype value, | |
92e059d8 ILT |
201 | typename elfcpp::Elf_types<size>::Elf_Addr address) |
202 | { | |
f6ce93d6 | 203 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; |
92e059d8 | 204 | Valtype* wv = reinterpret_cast<Valtype*>(view); |
f6ce93d6 ILT |
205 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); |
206 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address); | |
92e059d8 ILT |
207 | } |
208 | ||
b8e6aad9 ILT |
209 | // Do a simple PC relative relocation with a Symbol_value with the |
210 | // addend in the section contents. VALSIZE is the size of the | |
211 | // value. | |
212 | template<int valsize> | |
213 | static inline void | |
214 | pcrel(unsigned char* view, | |
215 | const Sized_relobj<size, big_endian>* object, | |
216 | const Symbol_value<size>* psymval, | |
217 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
218 | { | |
219 | typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype; | |
220 | Valtype* wv = reinterpret_cast<Valtype*>(view); | |
221 | Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv); | |
222 | x = psymval->value(object, x); | |
223 | elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address); | |
224 | } | |
225 | ||
92e059d8 ILT |
226 | typedef Relocate_functions<size, big_endian> This; |
227 | ||
228 | public: | |
b8e6aad9 ILT |
229 | // Do a simple 8-bit REL relocation with the addend in the section |
230 | // contents. | |
92e059d8 ILT |
231 | static inline void |
232 | rel8(unsigned char* view, unsigned char value) | |
b8e6aad9 ILT |
233 | { This::template rel<8>(view, value); } |
234 | ||
235 | static inline void | |
236 | rel8(unsigned char* view, | |
237 | const Sized_relobj<size, big_endian>* object, | |
238 | const Symbol_value<size>* psymval) | |
239 | { This::template rel<8>(view, object, psymval); } | |
92e059d8 ILT |
240 | |
241 | // Do a simple 8-bit PC relative relocation with the addend in the | |
b8e6aad9 | 242 | // section contents. |
92e059d8 ILT |
243 | static inline void |
244 | pcrel8(unsigned char* view, unsigned char value, | |
245 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
246 | { This::template pcrel<8>(view, value, address); } |
247 | ||
248 | static inline void | |
249 | pcrel8(unsigned char* view, | |
250 | const Sized_relobj<size, big_endian>* object, | |
251 | const Symbol_value<size>* psymval, | |
252 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
253 | { This::template pcrel<8>(view, object, psymval, address); } | |
92e059d8 | 254 | |
b8e6aad9 ILT |
255 | // Do a simple 16-bit REL relocation with the addend in the section |
256 | // contents. | |
92e059d8 ILT |
257 | static inline void |
258 | rel16(unsigned char* view, elfcpp::Elf_Half value) | |
b8e6aad9 ILT |
259 | { This::template rel<16>(view, value); } |
260 | ||
261 | static inline void | |
262 | rel16(unsigned char* view, | |
263 | const Sized_relobj<size, big_endian>* object, | |
264 | const Symbol_value<size>* psymval) | |
265 | { This::template rel<16>(view, object, psymval); } | |
92e059d8 ILT |
266 | |
267 | // Do a simple 32-bit PC relative REL relocation with the addend in | |
b8e6aad9 | 268 | // the section contents. |
92e059d8 ILT |
269 | static inline void |
270 | pcrel16(unsigned char* view, elfcpp::Elf_Word value, | |
271 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
272 | { This::template pcrel<16>(view, value, address); } |
273 | ||
274 | static inline void | |
275 | pcrel16(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<16>(view, object, psymval, address); } | |
92e059d8 ILT |
280 | |
281 | // Do a simple 32-bit REL relocation with the addend in the section | |
282 | // contents. | |
283 | static inline void | |
284 | rel32(unsigned char* view, elfcpp::Elf_Word value) | |
b8e6aad9 ILT |
285 | { This::template rel<32>(view, value); } |
286 | ||
287 | static inline void | |
288 | rel32(unsigned char* view, | |
289 | const Sized_relobj<size, big_endian>* object, | |
290 | const Symbol_value<size>* psymval) | |
291 | { This::template rel<32>(view, object, psymval); } | |
92e059d8 ILT |
292 | |
293 | // Do a simple 32-bit PC relative REL relocation with the addend in | |
294 | // the section contents. | |
295 | static inline void | |
296 | pcrel32(unsigned char* view, elfcpp::Elf_Word value, | |
297 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
b8e6aad9 ILT |
298 | { This::template pcrel<32>(view, value, address); } |
299 | ||
300 | static inline void | |
301 | pcrel32(unsigned char* view, | |
302 | const Sized_relobj<size, big_endian>* object, | |
303 | const Symbol_value<size>* psymval, | |
304 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
305 | { This::template pcrel<32>(view, object, psymval, address); } | |
92e059d8 ILT |
306 | |
307 | // Do a simple 64-bit REL relocation with the addend in the section | |
308 | // contents. | |
309 | static inline void | |
f6ce93d6 | 310 | rel64(unsigned char* view, elfcpp::Elf_Xword value) |
b8e6aad9 ILT |
311 | { This::template rel<64>(view, value); } |
312 | ||
313 | static inline void | |
314 | rel64(unsigned char* view, | |
315 | const Sized_relobj<size, big_endian>* object, | |
316 | const Symbol_value<size>* psymval) | |
317 | { This::template rel<64>(view, object, psymval); } | |
92e059d8 ILT |
318 | |
319 | // Do a simple 64-bit PC relative REL relocation with the addend in | |
320 | // the section contents. | |
321 | static inline void | |
f6ce93d6 | 322 | pcrel64(unsigned char* view, elfcpp::Elf_Xword value, |
92e059d8 | 323 | typename elfcpp::Elf_types<size>::Elf_Addr address) |
b8e6aad9 ILT |
324 | { This::template pcrel<64>(view, value, address); } |
325 | ||
326 | static inline void | |
327 | pcrel64(unsigned char* view, | |
328 | const Sized_relobj<size, big_endian>* object, | |
329 | const Symbol_value<size>* psymval, | |
330 | typename elfcpp::Elf_types<size>::Elf_Addr address) | |
331 | { This::template pcrel<64>(view, object, psymval, address); } | |
5a6f7e2d ILT |
332 | }; |
333 | ||
334 | // We try to avoid COPY relocations when possible. A COPY relocation | |
335 | // may be required when an executable refers to a variable defined in | |
336 | // a shared library. COPY relocations are problematic because they | |
337 | // tie the executable to the exact size of the variable in the shared | |
338 | // library. We can avoid them if all the references to the variable | |
339 | // are in a writeable section. In that case we can simply use dynamic | |
340 | // relocations. However, when scanning relocs, we don't know when we | |
341 | // see the relocation whether we will be forced to use a COPY | |
342 | // relocation or not. So we have to save the relocation during the | |
343 | // reloc scanning, and then emit it as a dynamic relocation if | |
344 | // necessary. This class implements that. It is used by the target | |
345 | // specific code. | |
346 | ||
347 | template<int size, bool big_endian> | |
348 | class Copy_relocs | |
349 | { | |
350 | public: | |
351 | Copy_relocs() | |
352 | : entries_() | |
353 | { } | |
a3ad94ed ILT |
354 | |
355 | // Return whether we need a COPY reloc for a reloc against GSYM, | |
356 | // which is being applied to section SHNDX in OBJECT. | |
357 | static bool | |
358 | need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx, | |
5a6f7e2d ILT |
359 | Sized_symbol<size>* gsym); |
360 | ||
361 | // Save a Rel against SYM for possible emission later. SHNDX is the | |
362 | // index of the section to which the reloc is being applied. | |
363 | void | |
364 | save(Symbol* sym, Relobj*, unsigned int shndx, | |
365 | const elfcpp::Rel<size, big_endian>&); | |
366 | ||
367 | // Save a Rela against SYM for possible emission later. | |
368 | void | |
369 | save(Symbol* sym, Relobj*, unsigned int shndx, | |
370 | const elfcpp::Rela<size, big_endian>&); | |
371 | ||
372 | // Return whether there are any relocs to emit. This also discards | |
373 | // entries which need not be emitted. | |
374 | bool | |
375 | any_to_emit(); | |
376 | ||
377 | // Emit relocs for each symbol which did not get a COPY reloc (i.e., | |
378 | // is still defined in the dynamic object). | |
379 | template<int sh_type> | |
380 | void | |
381 | emit(Output_data_reloc<sh_type, true, size, big_endian>*); | |
382 | ||
383 | private: | |
384 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; | |
385 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend; | |
386 | ||
387 | // This POD class holds the entries we are saving. | |
388 | class Copy_reloc_entry | |
389 | { | |
390 | public: | |
391 | Copy_reloc_entry(Symbol* sym, unsigned int reloc_type, | |
392 | Relobj* relobj, unsigned int shndx, | |
393 | Address address, Addend addend) | |
394 | : sym_(sym), reloc_type_(reloc_type), relobj_(relobj), | |
395 | shndx_(shndx), address_(address), addend_(addend) | |
396 | { } | |
397 | ||
398 | // Return whether we should emit this reloc. If we should not | |
399 | // emit, we clear it. | |
400 | bool | |
401 | should_emit(); | |
402 | ||
403 | // Emit this reloc. | |
404 | ||
405 | void | |
406 | emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*); | |
407 | ||
408 | void | |
409 | emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*); | |
410 | ||
411 | private: | |
412 | Symbol* sym_; | |
413 | unsigned int reloc_type_; | |
414 | Relobj* relobj_; | |
415 | unsigned int shndx_; | |
416 | Address address_; | |
417 | Addend addend_; | |
418 | }; | |
419 | ||
420 | // A list of relocs to be saved. | |
421 | typedef std::vector<Copy_reloc_entry> Copy_reloc_entries; | |
422 | ||
423 | // The list of relocs we are saving. | |
424 | Copy_reloc_entries entries_; | |
92e059d8 ILT |
425 | }; |
426 | ||
61ba1cf9 ILT |
427 | } // End namespace gold. |
428 | ||
429 | #endif // !defined(GOLD_RELOC_H) |