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61ba1cf9 ILT |
1 | // target-reloc.h -- target specific relocation support -*- C++ -*- |
2 | ||
6f2750fe | 3 | // Copyright (C) 2006-2016 Free Software Foundation, Inc. |
6cb15b7f ILT |
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_TARGET_RELOC_H |
24 | #define GOLD_TARGET_RELOC_H | |
25 | ||
26 | #include "elfcpp.h" | |
27 | #include "symtab.h" | |
364c7fa5 | 28 | #include "object.h" |
6a74a719 | 29 | #include "reloc.h" |
c06b7b0b | 30 | #include "reloc-types.h" |
61ba1cf9 ILT |
31 | |
32 | namespace gold | |
33 | { | |
34 | ||
6a74a719 ILT |
35 | // This function implements the generic part of reloc scanning. The |
36 | // template parameter Scan must be a class type which provides two | |
37 | // functions: local() and global(). Those functions implement the | |
38 | // machine specific part of scanning. We do it this way to | |
9b547ce6 | 39 | // avoid making a function call for each relocation, and to avoid |
6a74a719 | 40 | // repeating the generic code for each target. |
92e059d8 | 41 | |
4d625b70 CC |
42 | template<int size, bool big_endian, typename Target_type, |
43 | typename Scan, typename Classify_reloc> | |
92e059d8 ILT |
44 | inline void |
45 | scan_relocs( | |
92e059d8 | 46 | Symbol_table* symtab, |
ead1e424 ILT |
47 | Layout* layout, |
48 | Target_type* target, | |
6fa2a40b | 49 | Sized_relobj_file<size, big_endian>* object, |
a3ad94ed | 50 | unsigned int data_shndx, |
92e059d8 ILT |
51 | const unsigned char* prelocs, |
52 | size_t reloc_count, | |
730cdc88 ILT |
53 | Output_section* output_section, |
54 | bool needs_special_offset_handling, | |
92e059d8 | 55 | size_t local_count, |
730cdc88 | 56 | const unsigned char* plocal_syms) |
92e059d8 | 57 | { |
4d625b70 CC |
58 | typedef typename Classify_reloc::Reltype Reltype; |
59 | const int reloc_size = Classify_reloc::reloc_size; | |
92e059d8 ILT |
60 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; |
61 | Scan scan; | |
62 | ||
63 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
64 | { | |
65 | Reltype reloc(prelocs); | |
66 | ||
730cdc88 ILT |
67 | if (needs_special_offset_handling |
68 | && !output_section->is_input_address_mapped(object, data_shndx, | |
69 | reloc.get_r_offset())) | |
70 | continue; | |
71 | ||
4d625b70 CC |
72 | unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); |
73 | unsigned int r_type = Classify_reloc::get_r_type(&reloc); | |
92e059d8 ILT |
74 | |
75 | if (r_sym < local_count) | |
76 | { | |
a3ad94ed | 77 | gold_assert(plocal_syms != NULL); |
92e059d8 ILT |
78 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms |
79 | + r_sym * sym_size); | |
d491d34e ILT |
80 | unsigned int shndx = lsym.get_st_shndx(); |
81 | bool is_ordinary; | |
82 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
bfdfa4cd AM |
83 | // If RELOC is a relocation against a local symbol in a |
84 | // section we are discarding then we can ignore it. It will | |
85 | // eventually become a reloc against the value zero. | |
86 | // | |
87 | // FIXME: We should issue a warning if this is an | |
88 | // allocated section; is this the best place to do it? | |
62fe925a | 89 | // |
bfdfa4cd AM |
90 | // FIXME: The old GNU linker would in some cases look |
91 | // for the linkonce section which caused this section to | |
92 | // be discarded, and, if the other section was the same | |
93 | // size, change the reloc to refer to the other section. | |
94 | // That seems risky and weird to me, and I don't know of | |
95 | // any case where it is actually required. | |
96 | bool is_discarded = (is_ordinary | |
97 | && shndx != elfcpp::SHN_UNDEF | |
98 | && !object->is_section_included(shndx) | |
99 | && !symtab->is_section_folded(object, shndx)); | |
ad0f2072 | 100 | scan.local(symtab, layout, target, object, data_shndx, |
bfdfa4cd | 101 | output_section, reloc, r_type, lsym, is_discarded); |
92e059d8 ILT |
102 | } |
103 | else | |
104 | { | |
730cdc88 | 105 | Symbol* gsym = object->global_symbol(r_sym); |
a3ad94ed | 106 | gold_assert(gsym != NULL); |
92e059d8 ILT |
107 | if (gsym->is_forwarder()) |
108 | gsym = symtab->resolve_forwards(gsym); | |
109 | ||
ad0f2072 | 110 | scan.global(symtab, layout, target, object, data_shndx, |
07f397ab | 111 | output_section, reloc, r_type, gsym); |
92e059d8 ILT |
112 | } |
113 | } | |
114 | } | |
115 | ||
e94cf127 CC |
116 | // Behavior for relocations to discarded comdat sections. |
117 | ||
118 | enum Comdat_behavior | |
119 | { | |
120 | CB_UNDETERMINED, // Not yet determined -- need to look at section name. | |
121 | CB_PRETEND, // Attempt to map to the corresponding kept section. | |
122 | CB_IGNORE, // Ignore the relocation. | |
123 | CB_WARNING // Print a warning. | |
124 | }; | |
125 | ||
168a4726 | 126 | class Default_comdat_behavior |
e94cf127 | 127 | { |
168a4726 AM |
128 | public: |
129 | // Decide what the linker should do for relocations that refer to | |
130 | // discarded comdat sections. This decision is based on the name of | |
131 | // the section being relocated. | |
132 | ||
133 | inline Comdat_behavior | |
134 | get(const char* name) | |
135 | { | |
136 | if (Layout::is_debug_info_section(name)) | |
137 | return CB_PRETEND; | |
138 | if (strcmp(name, ".eh_frame") == 0 | |
139 | || strcmp(name, ".gcc_except_table") == 0) | |
140 | return CB_IGNORE; | |
141 | return CB_WARNING; | |
142 | } | |
143 | }; | |
e94cf127 | 144 | |
837504c4 ILT |
145 | // Give an error for a symbol with non-default visibility which is not |
146 | // defined locally. | |
147 | ||
148 | inline void | |
149 | visibility_error(const Symbol* sym) | |
150 | { | |
151 | const char* v; | |
152 | switch (sym->visibility()) | |
153 | { | |
154 | case elfcpp::STV_INTERNAL: | |
155 | v = _("internal"); | |
156 | break; | |
157 | case elfcpp::STV_HIDDEN: | |
158 | v = _("hidden"); | |
159 | break; | |
160 | case elfcpp::STV_PROTECTED: | |
161 | v = _("protected"); | |
162 | break; | |
163 | default: | |
164 | gold_unreachable(); | |
165 | } | |
166 | gold_error(_("%s symbol '%s' is not defined locally"), | |
167 | v, sym->name()); | |
168 | } | |
169 | ||
191f1a2d ILT |
170 | // Return true if we are should issue an error saying that SYM is an |
171 | // undefined symbol. This is called if there is a relocation against | |
172 | // SYM. | |
173 | ||
174 | inline bool | |
175 | issue_undefined_symbol_error(const Symbol* sym) | |
176 | { | |
beabb2c6 ILT |
177 | // We only report global symbols. |
178 | if (sym == NULL) | |
179 | return false; | |
180 | ||
181 | // We only report undefined symbols. | |
182 | if (!sym->is_undefined() && !sym->is_placeholder()) | |
183 | return false; | |
184 | ||
185 | // We don't report weak symbols. | |
d1bddd3c | 186 | if (sym->is_weak_undefined()) |
beabb2c6 ILT |
187 | return false; |
188 | ||
189 | // We don't report symbols defined in discarded sections. | |
190 | if (sym->is_defined_in_discarded_section()) | |
191 | return false; | |
192 | ||
193 | // If the target defines this symbol, don't report it here. | |
194 | if (parameters->target().is_defined_by_abi(sym)) | |
195 | return false; | |
196 | ||
197 | // See if we've been told to ignore whether this symbol is | |
198 | // undefined. | |
199 | const char* const u = parameters->options().unresolved_symbols(); | |
200 | if (u != NULL) | |
201 | { | |
202 | if (strcmp(u, "ignore-all") == 0) | |
203 | return false; | |
e2153196 ILT |
204 | if (strcmp(u, "report-all") == 0) |
205 | return true; | |
beabb2c6 ILT |
206 | if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn()) |
207 | return false; | |
208 | if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg()) | |
209 | return false; | |
210 | } | |
211 | ||
d1bddd3c CC |
212 | // If the symbol is hidden, report it. |
213 | if (sym->visibility() == elfcpp::STV_HIDDEN) | |
214 | return true; | |
215 | ||
beabb2c6 ILT |
216 | // When creating a shared library, only report unresolved symbols if |
217 | // -z defs was used. | |
218 | if (parameters->options().shared() && !parameters->options().defs()) | |
219 | return false; | |
220 | ||
221 | // Otherwise issue a warning. | |
222 | return true; | |
191f1a2d ILT |
223 | } |
224 | ||
92e059d8 | 225 | // This function implements the generic part of relocation processing. |
6a74a719 ILT |
226 | // The template parameter Relocate must be a class type which provides |
227 | // a single function, relocate(), which implements the machine | |
228 | // specific part of a relocation. | |
61ba1cf9 | 229 | |
168a4726 AM |
230 | // The template parameter Relocate_comdat_behavior is a class type |
231 | // which provides a single function, get(), which determines what the | |
232 | // linker should do for relocations that refer to discarded comdat | |
233 | // sections. | |
234 | ||
61ba1cf9 | 235 | // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of |
92e059d8 ILT |
236 | // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA. |
237 | // RELOCATE implements operator() to do a relocation. | |
61ba1cf9 | 238 | |
92e059d8 | 239 | // PRELOCS points to the relocation data. RELOC_COUNT is the number |
730cdc88 ILT |
240 | // of relocs. OUTPUT_SECTION is the output section. |
241 | // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be | |
242 | // mapped to output offsets. | |
243 | ||
244 | // VIEW is the section data, VIEW_ADDRESS is its memory address, and | |
245 | // VIEW_SIZE is the size. These refer to the input section, unless | |
246 | // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to | |
247 | // the output section. | |
61ba1cf9 | 248 | |
364c7fa5 ILT |
249 | // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is |
250 | // not NULL, it is a vector indexed by relocation index. If that | |
251 | // entry is not NULL, it points to a global symbol which used as the | |
252 | // symbol for the relocation, ignoring the symbol index in the | |
253 | // relocation. | |
254 | ||
4d625b70 | 255 | template<int size, bool big_endian, typename Target_type, |
168a4726 | 256 | typename Relocate, |
4d625b70 CC |
257 | typename Relocate_comdat_behavior, |
258 | typename Classify_reloc> | |
61ba1cf9 ILT |
259 | inline void |
260 | relocate_section( | |
92e059d8 | 261 | const Relocate_info<size, big_endian>* relinfo, |
ead1e424 | 262 | Target_type* target, |
61ba1cf9 ILT |
263 | const unsigned char* prelocs, |
264 | size_t reloc_count, | |
730cdc88 ILT |
265 | Output_section* output_section, |
266 | bool needs_special_offset_handling, | |
61ba1cf9 ILT |
267 | unsigned char* view, |
268 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, | |
364c7fa5 ILT |
269 | section_size_type view_size, |
270 | const Reloc_symbol_changes* reloc_symbol_changes) | |
61ba1cf9 | 271 | { |
4d625b70 CC |
272 | typedef typename Classify_reloc::Reltype Reltype; |
273 | const int reloc_size = Classify_reloc::reloc_size; | |
61ba1cf9 | 274 | Relocate relocate; |
168a4726 | 275 | Relocate_comdat_behavior relocate_comdat_behavior; |
61ba1cf9 | 276 | |
6fa2a40b | 277 | Sized_relobj_file<size, big_endian>* object = relinfo->object; |
730cdc88 | 278 | unsigned int local_count = object->local_symbol_count(); |
92e059d8 | 279 | |
e94cf127 CC |
280 | Comdat_behavior comdat_behavior = CB_UNDETERMINED; |
281 | ||
61ba1cf9 ILT |
282 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) |
283 | { | |
284 | Reltype reloc(prelocs); | |
285 | ||
fe8718a4 ILT |
286 | section_offset_type offset = |
287 | convert_to_section_size_type(reloc.get_r_offset()); | |
61ba1cf9 | 288 | |
730cdc88 ILT |
289 | if (needs_special_offset_handling) |
290 | { | |
291 | offset = output_section->output_offset(relinfo->object, | |
292 | relinfo->data_shndx, | |
293 | offset); | |
294 | if (offset == -1) | |
295 | continue; | |
296 | } | |
297 | ||
4d625b70 | 298 | unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); |
61ba1cf9 | 299 | |
c06b7b0b | 300 | const Sized_symbol<size>* sym; |
61ba1cf9 | 301 | |
b8e6aad9 ILT |
302 | Symbol_value<size> symval; |
303 | const Symbol_value<size> *psymval; | |
880cd20d ILT |
304 | bool is_defined_in_discarded_section; |
305 | unsigned int shndx; | |
364c7fa5 ILT |
306 | if (r_sym < local_count |
307 | && (reloc_symbol_changes == NULL | |
308 | || (*reloc_symbol_changes)[i] == NULL)) | |
61ba1cf9 ILT |
309 | { |
310 | sym = NULL; | |
730cdc88 | 311 | psymval = object->local_symbol(r_sym); |
e94cf127 CC |
312 | |
313 | // If the local symbol belongs to a section we are discarding, | |
314 | // and that section is a debug section, try to find the | |
315 | // corresponding kept section and map this symbol to its | |
62fe925a | 316 | // counterpart in the kept section. The symbol must not |
ef15dade | 317 | // correspond to a section we are folding. |
e94cf127 | 318 | bool is_ordinary; |
880cd20d ILT |
319 | shndx = psymval->input_shndx(&is_ordinary); |
320 | is_defined_in_discarded_section = | |
321 | (is_ordinary | |
322 | && shndx != elfcpp::SHN_UNDEF | |
323 | && !object->is_section_included(shndx) | |
324 | && !relinfo->symtab->is_section_folded(object, shndx)); | |
61ba1cf9 ILT |
325 | } |
326 | else | |
327 | { | |
364c7fa5 ILT |
328 | const Symbol* gsym; |
329 | if (reloc_symbol_changes != NULL | |
330 | && (*reloc_symbol_changes)[i] != NULL) | |
331 | gsym = (*reloc_symbol_changes)[i]; | |
332 | else | |
333 | { | |
334 | gsym = object->global_symbol(r_sym); | |
335 | gold_assert(gsym != NULL); | |
336 | if (gsym->is_forwarder()) | |
337 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
338 | } | |
61ba1cf9 | 339 | |
c06b7b0b | 340 | sym = static_cast<const Sized_symbol<size>*>(gsym); |
d3bbad62 | 341 | if (sym->has_symtab_index() && sym->symtab_index() != -1U) |
b8e6aad9 ILT |
342 | symval.set_output_symtab_index(sym->symtab_index()); |
343 | else | |
344 | symval.set_no_output_symtab_entry(); | |
345 | symval.set_output_value(sym->value()); | |
7223e9ca ILT |
346 | if (gsym->type() == elfcpp::STT_TLS) |
347 | symval.set_is_tls_symbol(); | |
348 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
349 | symval.set_is_ifunc_symbol(); | |
b8e6aad9 | 350 | psymval = &symval; |
880cd20d ILT |
351 | |
352 | is_defined_in_discarded_section = | |
353 | (gsym->is_defined_in_discarded_section() | |
354 | && gsym->is_undefined()); | |
355 | shndx = 0; | |
356 | } | |
357 | ||
358 | Symbol_value<size> symval2; | |
359 | if (is_defined_in_discarded_section) | |
360 | { | |
361 | if (comdat_behavior == CB_UNDETERMINED) | |
362 | { | |
363 | std::string name = object->section_name(relinfo->data_shndx); | |
168a4726 | 364 | comdat_behavior = relocate_comdat_behavior.get(name.c_str()); |
880cd20d ILT |
365 | } |
366 | if (comdat_behavior == CB_PRETEND) | |
367 | { | |
368 | // FIXME: This case does not work for global symbols. | |
369 | // We have no place to store the original section index. | |
370 | // Fortunately this does not matter for comdat sections, | |
371 | // only for sections explicitly discarded by a linker | |
372 | // script. | |
373 | bool found; | |
374 | typename elfcpp::Elf_types<size>::Elf_Addr value = | |
375 | object->map_to_kept_section(shndx, &found); | |
376 | if (found) | |
377 | symval2.set_output_value(value + psymval->input_value()); | |
378 | else | |
379 | symval2.set_output_value(0); | |
380 | } | |
381 | else | |
382 | { | |
383 | if (comdat_behavior == CB_WARNING) | |
384 | gold_warning_at_location(relinfo, i, offset, | |
385 | _("relocation refers to discarded " | |
386 | "section")); | |
387 | symval2.set_output_value(0); | |
388 | } | |
389 | symval2.set_no_output_symtab_entry(); | |
390 | psymval = &symval2; | |
ead1e424 | 391 | } |
61ba1cf9 | 392 | |
0e804863 ILT |
393 | // If OFFSET is out of range, still let the target decide to |
394 | // ignore the relocation. Pass in NULL as the VIEW argument so | |
395 | // that it can return quickly without trashing an invalid memory | |
396 | // address. | |
397 | unsigned char *v = view + offset; | |
398 | if (offset < 0 || static_cast<section_size_type>(offset) >= view_size) | |
399 | v = NULL; | |
400 | ||
4d625b70 CC |
401 | if (!relocate.relocate(relinfo, Classify_reloc::sh_type, target, |
402 | output_section, i, prelocs, sym, psymval, | |
91a65d2f | 403 | v, view_address + offset, view_size)) |
ead1e424 ILT |
404 | continue; |
405 | ||
0e804863 | 406 | if (v == NULL) |
ead1e424 | 407 | { |
75f2446e ILT |
408 | gold_error_at_location(relinfo, i, offset, |
409 | _("reloc has bad offset %zu"), | |
410 | static_cast<size_t>(offset)); | |
411 | continue; | |
61ba1cf9 ILT |
412 | } |
413 | ||
191f1a2d | 414 | if (issue_undefined_symbol_error(sym)) |
1a221d3d | 415 | gold_undefined_symbol_at_location(sym, relinfo, i, offset); |
837504c4 ILT |
416 | else if (sym != NULL |
417 | && sym->visibility() != elfcpp::STV_DEFAULT | |
d1bddd3c | 418 | && (sym->is_strong_undefined() || sym->is_from_dynobj())) |
837504c4 | 419 | visibility_error(sym); |
f6ce93d6 ILT |
420 | |
421 | if (sym != NULL && sym->has_warning()) | |
75f2446e | 422 | relinfo->symtab->issue_warning(sym, relinfo, i, offset); |
61ba1cf9 ILT |
423 | } |
424 | } | |
425 | ||
94a3fc8b CC |
426 | // Apply an incremental relocation. |
427 | ||
428 | template<int size, bool big_endian, typename Target_type, | |
429 | typename Relocate> | |
430 | void | |
431 | apply_relocation(const Relocate_info<size, big_endian>* relinfo, | |
432 | Target_type* target, | |
433 | typename elfcpp::Elf_types<size>::Elf_Addr r_offset, | |
434 | unsigned int r_type, | |
435 | typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, | |
436 | const Symbol* gsym, | |
437 | unsigned char* view, | |
438 | typename elfcpp::Elf_types<size>::Elf_Addr address, | |
439 | section_size_type view_size) | |
440 | { | |
441 | // Construct the ELF relocation in a temporary buffer. | |
d55525b9 | 442 | const int reloc_size = elfcpp::Elf_sizes<size>::rela_size; |
94a3fc8b | 443 | unsigned char relbuf[reloc_size]; |
d55525b9 | 444 | elfcpp::Rela_write<size, big_endian> orel(relbuf); |
94a3fc8b | 445 | orel.put_r_offset(r_offset); |
d55525b9 | 446 | orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type)); |
94a3fc8b CC |
447 | orel.put_r_addend(r_addend); |
448 | ||
449 | // Setup a Symbol_value for the global symbol. | |
d55525b9 L |
450 | const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym); |
451 | Symbol_value<size> symval; | |
94a3fc8b CC |
452 | gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U); |
453 | symval.set_output_symtab_index(sym->symtab_index()); | |
454 | symval.set_output_value(sym->value()); | |
455 | if (gsym->type() == elfcpp::STT_TLS) | |
456 | symval.set_is_tls_symbol(); | |
457 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
458 | symval.set_is_ifunc_symbol(); | |
459 | ||
460 | Relocate relocate; | |
91a65d2f AM |
461 | relocate.relocate(relinfo, elfcpp::SHT_RELA, target, NULL, |
462 | -1U, relbuf, sym, &symval, | |
94a3fc8b CC |
463 | view + r_offset, address + r_offset, view_size); |
464 | } | |
465 | ||
4d625b70 CC |
466 | // A class for inquiring about properties of a relocation, |
467 | // used while scanning relocs during a relocatable link and | |
468 | // garbage collection. This class may be used as the default | |
469 | // for SHT_RELA targets, but SHT_REL targets must implement | |
470 | // a derived class that overrides get_size_for_reloc. | |
471 | // The MIPS-64 target also needs to override the methods | |
472 | // for accessing the r_sym and r_type fields of a relocation, | |
473 | // due to its non-standard use of the r_info field. | |
474 | ||
475 | template<int sh_type_, int size, bool big_endian> | |
476 | class Default_classify_reloc | |
477 | { | |
478 | public: | |
479 | typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc | |
480 | Reltype; | |
481 | typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc_write | |
482 | Reltype_write; | |
483 | static const int reloc_size = | |
484 | Reloc_types<sh_type_, size, big_endian>::reloc_size; | |
485 | static const int sh_type = sh_type_; | |
486 | ||
487 | // Return the symbol referred to by the relocation. | |
488 | static inline unsigned int | |
489 | get_r_sym(const Reltype* reloc) | |
490 | { return elfcpp::elf_r_sym<size>(reloc->get_r_info()); } | |
491 | ||
492 | // Return the type of the relocation. | |
493 | static inline unsigned int | |
494 | get_r_type(const Reltype* reloc) | |
495 | { return elfcpp::elf_r_type<size>(reloc->get_r_info()); } | |
496 | ||
497 | // Return the explicit addend of the relocation (return 0 for SHT_REL). | |
498 | static inline typename elfcpp::Elf_types<size>::Elf_Swxword | |
499 | get_r_addend(const Reltype* reloc) | |
500 | { return Reloc_types<sh_type_, size, big_endian>::get_reloc_addend(reloc); } | |
501 | ||
502 | // Write the r_info field to a new reloc, using the r_info field from | |
503 | // the original reloc, replacing the r_sym field with R_SYM. | |
504 | static inline void | |
505 | put_r_info(Reltype_write* new_reloc, Reltype* reloc, unsigned int r_sym) | |
506 | { | |
507 | unsigned int r_type = elfcpp::elf_r_type<size>(reloc->get_r_info()); | |
508 | new_reloc->put_r_info(elfcpp::elf_r_info<size>(r_sym, r_type)); | |
509 | } | |
510 | ||
511 | // Write the r_addend field to a new reloc. | |
512 | static inline void | |
513 | put_r_addend(Reltype_write* to, | |
514 | typename elfcpp::Elf_types<size>::Elf_Swxword addend) | |
515 | { Reloc_types<sh_type_, size, big_endian>::set_reloc_addend(to, addend); } | |
516 | ||
517 | // Return the size of the addend of the relocation (only used for SHT_REL). | |
518 | static unsigned int | |
519 | get_size_for_reloc(unsigned int, Relobj*) | |
520 | { | |
521 | gold_unreachable(); | |
522 | return 0; | |
523 | } | |
524 | }; | |
525 | ||
6a74a719 | 526 | // This class may be used as a typical class for the |
4d625b70 CC |
527 | // Scan_relocatable_reloc parameter to scan_relocatable_relocs. |
528 | // This class is intended to capture the most typical target behaviour, | |
529 | // while still permitting targets to define their own independent class | |
530 | // for Scan_relocatable_reloc. | |
531 | ||
532 | template<typename Classify_reloc> | |
6a74a719 ILT |
533 | class Default_scan_relocatable_relocs |
534 | { | |
535 | public: | |
4d625b70 CC |
536 | typedef typename Classify_reloc::Reltype Reltype; |
537 | static const int reloc_size = Classify_reloc::reloc_size; | |
538 | static const int sh_type = Classify_reloc::sh_type; | |
539 | ||
540 | // Return the symbol referred to by the relocation. | |
541 | static inline unsigned int | |
542 | get_r_sym(const Reltype* reloc) | |
543 | { return Classify_reloc::get_r_sym(reloc); } | |
544 | ||
545 | // Return the type of the relocation. | |
546 | static inline unsigned int | |
547 | get_r_type(const Reltype* reloc) | |
548 | { return Classify_reloc::get_r_type(reloc); } | |
549 | ||
6a74a719 ILT |
550 | // Return the strategy to use for a local symbol which is not a |
551 | // section symbol, given the relocation type. | |
552 | inline Relocatable_relocs::Reloc_strategy | |
68943102 | 553 | local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym) |
c2508178 ILT |
554 | { |
555 | // We assume that relocation type 0 is NONE. Targets which are | |
556 | // different must override. | |
68943102 | 557 | if (r_type == 0 && r_sym == 0) |
c2508178 ILT |
558 | return Relocatable_relocs::RELOC_DISCARD; |
559 | return Relocatable_relocs::RELOC_COPY; | |
560 | } | |
6a74a719 ILT |
561 | |
562 | // Return the strategy to use for a local symbol which is a section | |
563 | // symbol, given the relocation type. | |
564 | inline Relocatable_relocs::Reloc_strategy | |
565 | local_section_strategy(unsigned int r_type, Relobj* object) | |
566 | { | |
567 | if (sh_type == elfcpp::SHT_RELA) | |
568 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; | |
569 | else | |
570 | { | |
4d625b70 | 571 | switch (Classify_reloc::get_size_for_reloc(r_type, object)) |
6a74a719 ILT |
572 | { |
573 | case 0: | |
7019cd25 | 574 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; |
6a74a719 ILT |
575 | case 1: |
576 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1; | |
577 | case 2: | |
578 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2; | |
579 | case 4: | |
580 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4; | |
581 | case 8: | |
582 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8; | |
583 | default: | |
584 | gold_unreachable(); | |
585 | } | |
586 | } | |
587 | } | |
588 | ||
589 | // Return the strategy to use for a global symbol, given the | |
590 | // relocation type, the object, and the symbol index. | |
591 | inline Relocatable_relocs::Reloc_strategy | |
68943102 ILT |
592 | global_strategy(unsigned int, Relobj*, unsigned int) |
593 | { return Relocatable_relocs::RELOC_COPY; } | |
6a74a719 ILT |
594 | }; |
595 | ||
4d625b70 CC |
596 | // This is a strategy class used with scan_relocatable_relocs |
597 | // and --emit-relocs. | |
598 | ||
599 | template<typename Classify_reloc> | |
600 | class Default_emit_relocs_strategy | |
601 | { | |
602 | public: | |
603 | typedef typename Classify_reloc::Reltype Reltype; | |
604 | static const int reloc_size = Classify_reloc::reloc_size; | |
605 | static const int sh_type = Classify_reloc::sh_type; | |
606 | ||
607 | // Return the symbol referred to by the relocation. | |
608 | static inline unsigned int | |
609 | get_r_sym(const Reltype* reloc) | |
610 | { return Classify_reloc::get_r_sym(reloc); } | |
611 | ||
612 | // Return the type of the relocation. | |
613 | static inline unsigned int | |
614 | get_r_type(const Reltype* reloc) | |
615 | { return Classify_reloc::get_r_type(reloc); } | |
616 | ||
617 | // A local non-section symbol. | |
618 | inline Relocatable_relocs::Reloc_strategy | |
619 | local_non_section_strategy(unsigned int, Relobj*, unsigned int) | |
620 | { return Relocatable_relocs::RELOC_COPY; } | |
621 | ||
622 | // A local section symbol. | |
623 | inline Relocatable_relocs::Reloc_strategy | |
624 | local_section_strategy(unsigned int, Relobj*) | |
625 | { | |
626 | if (sh_type == elfcpp::SHT_RELA) | |
627 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; | |
628 | else | |
629 | { | |
630 | // The addend is stored in the section contents. Since this | |
631 | // is not a relocatable link, we are going to apply the | |
632 | // relocation contents to the section as usual. This means | |
633 | // that we have no way to record the original addend. If the | |
634 | // original addend is not zero, there is basically no way for | |
635 | // the user to handle this correctly. Caveat emptor. | |
636 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; | |
637 | } | |
638 | } | |
639 | ||
640 | // A global symbol. | |
641 | inline Relocatable_relocs::Reloc_strategy | |
642 | global_strategy(unsigned int, Relobj*, unsigned int) | |
643 | { return Relocatable_relocs::RELOC_COPY; } | |
644 | }; | |
645 | ||
6a74a719 ILT |
646 | // Scan relocs during a relocatable link. This is a default |
647 | // definition which should work for most targets. | |
648 | // Scan_relocatable_reloc must name a class type which provides three | |
649 | // functions which return a Relocatable_relocs::Reloc_strategy code: | |
650 | // global_strategy, local_non_section_strategy, and | |
651 | // local_section_strategy. Most targets should be able to use | |
652 | // Default_scan_relocatable_relocs as this class. | |
653 | ||
4d625b70 | 654 | template<int size, bool big_endian, typename Scan_relocatable_reloc> |
6a74a719 ILT |
655 | void |
656 | scan_relocatable_relocs( | |
6a74a719 ILT |
657 | Symbol_table*, |
658 | Layout*, | |
6fa2a40b | 659 | Sized_relobj_file<size, big_endian>* object, |
6a74a719 ILT |
660 | unsigned int data_shndx, |
661 | const unsigned char* prelocs, | |
662 | size_t reloc_count, | |
663 | Output_section* output_section, | |
664 | bool needs_special_offset_handling, | |
665 | size_t local_symbol_count, | |
666 | const unsigned char* plocal_syms, | |
667 | Relocatable_relocs* rr) | |
668 | { | |
4d625b70 CC |
669 | typedef typename Scan_relocatable_reloc::Reltype Reltype; |
670 | const int reloc_size = Scan_relocatable_reloc::reloc_size; | |
6a74a719 ILT |
671 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; |
672 | Scan_relocatable_reloc scan; | |
673 | ||
674 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
675 | { | |
676 | Reltype reloc(prelocs); | |
677 | ||
678 | Relocatable_relocs::Reloc_strategy strategy; | |
679 | ||
680 | if (needs_special_offset_handling | |
681 | && !output_section->is_input_address_mapped(object, data_shndx, | |
682 | reloc.get_r_offset())) | |
683 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
684 | else | |
685 | { | |
4d625b70 CC |
686 | const unsigned int r_sym = Scan_relocatable_reloc::get_r_sym(&reloc); |
687 | const unsigned int r_type = | |
688 | Scan_relocatable_reloc::get_r_type(&reloc); | |
6a74a719 ILT |
689 | |
690 | if (r_sym >= local_symbol_count) | |
691 | strategy = scan.global_strategy(r_type, object, r_sym); | |
692 | else | |
693 | { | |
694 | gold_assert(plocal_syms != NULL); | |
695 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms | |
696 | + r_sym * sym_size); | |
d491d34e ILT |
697 | unsigned int shndx = lsym.get_st_shndx(); |
698 | bool is_ordinary; | |
699 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
700 | if (is_ordinary | |
6a74a719 | 701 | && shndx != elfcpp::SHN_UNDEF |
d491d34e | 702 | && !object->is_section_included(shndx)) |
6a74a719 ILT |
703 | { |
704 | // RELOC is a relocation against a local symbol | |
705 | // defined in a section we are discarding. Discard | |
706 | // the reloc. FIXME: Should we issue a warning? | |
707 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
708 | } | |
709 | else if (lsym.get_st_type() != elfcpp::STT_SECTION) | |
68943102 ILT |
710 | strategy = scan.local_non_section_strategy(r_type, object, |
711 | r_sym); | |
6a74a719 ILT |
712 | else |
713 | { | |
714 | strategy = scan.local_section_strategy(r_type, object); | |
715 | if (strategy != Relocatable_relocs::RELOC_DISCARD) | |
ef9beddf | 716 | object->output_section(shndx)->set_needs_symtab_index(); |
6a74a719 | 717 | } |
d3bbad62 ILT |
718 | |
719 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
720 | object->set_must_have_output_symtab_entry(r_sym); | |
6a74a719 ILT |
721 | } |
722 | } | |
723 | ||
724 | rr->set_next_reloc_strategy(strategy); | |
725 | } | |
726 | } | |
727 | ||
7404fe1b AM |
728 | // Relocate relocs. Called for a relocatable link, and for --emit-relocs. |
729 | // This is a default definition which should work for most targets. | |
6a74a719 | 730 | |
4d625b70 | 731 | template<int size, bool big_endian, typename Classify_reloc> |
6a74a719 | 732 | void |
7404fe1b | 733 | relocate_relocs( |
6a74a719 ILT |
734 | const Relocate_info<size, big_endian>* relinfo, |
735 | const unsigned char* prelocs, | |
736 | size_t reloc_count, | |
737 | Output_section* output_section, | |
62fe925a | 738 | typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, |
6a74a719 | 739 | unsigned char* view, |
6be6f3bd | 740 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
5c388529 | 741 | section_size_type view_size, |
6a74a719 ILT |
742 | unsigned char* reloc_view, |
743 | section_size_type reloc_view_size) | |
744 | { | |
ef9beddf | 745 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
4d625b70 CC |
746 | typedef typename Classify_reloc::Reltype Reltype; |
747 | typedef typename Classify_reloc::Reltype_write Reltype_write; | |
748 | const int reloc_size = Classify_reloc::reloc_size; | |
eff45813 | 749 | const Address invalid_address = static_cast<Address>(0) - 1; |
6a74a719 | 750 | |
6fa2a40b | 751 | Sized_relobj_file<size, big_endian>* const object = relinfo->object; |
6a74a719 ILT |
752 | const unsigned int local_count = object->local_symbol_count(); |
753 | ||
754 | unsigned char* pwrite = reloc_view; | |
755 | ||
756 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
757 | { | |
91a65d2f | 758 | Relocatable_relocs::Reloc_strategy strategy = relinfo->rr->strategy(i); |
6a74a719 ILT |
759 | if (strategy == Relocatable_relocs::RELOC_DISCARD) |
760 | continue; | |
761 | ||
5c388529 DK |
762 | if (strategy == Relocatable_relocs::RELOC_SPECIAL) |
763 | { | |
764 | // Target wants to handle this relocation. | |
765 | Sized_target<size, big_endian>* target = | |
766 | parameters->sized_target<size, big_endian>(); | |
4d625b70 CC |
767 | target->relocate_special_relocatable(relinfo, Classify_reloc::sh_type, |
768 | prelocs, i, output_section, | |
5c388529 DK |
769 | offset_in_output_section, |
770 | view, view_address, | |
771 | view_size, pwrite); | |
772 | pwrite += reloc_size; | |
773 | continue; | |
774 | } | |
6a74a719 ILT |
775 | Reltype reloc(prelocs); |
776 | Reltype_write reloc_write(pwrite); | |
777 | ||
4d625b70 | 778 | const unsigned int r_sym = Classify_reloc::get_r_sym(&reloc); |
6a74a719 ILT |
779 | |
780 | // Get the new symbol index. | |
781 | ||
9215b98b | 782 | Output_section* os = NULL; |
6a74a719 ILT |
783 | unsigned int new_symndx; |
784 | if (r_sym < local_count) | |
785 | { | |
786 | switch (strategy) | |
787 | { | |
788 | case Relocatable_relocs::RELOC_COPY: | |
818bf354 ILT |
789 | if (r_sym == 0) |
790 | new_symndx = 0; | |
791 | else | |
792 | { | |
793 | new_symndx = object->symtab_index(r_sym); | |
794 | gold_assert(new_symndx != -1U); | |
795 | } | |
6a74a719 ILT |
796 | break; |
797 | ||
798 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
7019cd25 | 799 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
6a74a719 ILT |
800 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
801 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
802 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
803 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
2c339f71 | 804 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
6a74a719 ILT |
805 | { |
806 | // We are adjusting a section symbol. We need to find | |
807 | // the symbol table index of the section symbol for | |
808 | // the output section corresponding to input section | |
809 | // in which this symbol is defined. | |
810 | gold_assert(r_sym < local_count); | |
d491d34e ILT |
811 | bool is_ordinary; |
812 | unsigned int shndx = | |
813 | object->local_symbol_input_shndx(r_sym, &is_ordinary); | |
814 | gold_assert(is_ordinary); | |
9215b98b | 815 | os = object->output_section(shndx); |
6a74a719 ILT |
816 | gold_assert(os != NULL); |
817 | gold_assert(os->needs_symtab_index()); | |
818 | new_symndx = os->symtab_index(); | |
819 | } | |
820 | break; | |
821 | ||
822 | default: | |
823 | gold_unreachable(); | |
824 | } | |
825 | } | |
826 | else | |
827 | { | |
828 | const Symbol* gsym = object->global_symbol(r_sym); | |
829 | gold_assert(gsym != NULL); | |
830 | if (gsym->is_forwarder()) | |
831 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
832 | ||
833 | gold_assert(gsym->has_symtab_index()); | |
834 | new_symndx = gsym->symtab_index(); | |
835 | } | |
836 | ||
837 | // Get the new offset--the location in the output section where | |
838 | // this relocation should be applied. | |
839 | ||
ef9beddf ILT |
840 | Address offset = reloc.get_r_offset(); |
841 | Address new_offset; | |
eff45813 | 842 | if (offset_in_output_section != invalid_address) |
6a74a719 ILT |
843 | new_offset = offset + offset_in_output_section; |
844 | else | |
845 | { | |
ef9beddf ILT |
846 | section_offset_type sot_offset = |
847 | convert_types<section_offset_type, Address>(offset); | |
848 | section_offset_type new_sot_offset = | |
849 | output_section->output_offset(object, relinfo->data_shndx, | |
850 | sot_offset); | |
851 | gold_assert(new_sot_offset != -1); | |
852 | new_offset = new_sot_offset; | |
6a74a719 ILT |
853 | } |
854 | ||
6be6f3bd ILT |
855 | // In an object file, r_offset is an offset within the section. |
856 | // In an executable or dynamic object, generated by | |
857 | // --emit-relocs, r_offset is an absolute address. | |
858 | if (!parameters->options().relocatable()) | |
e09ad04a ILT |
859 | { |
860 | new_offset += view_address; | |
eff45813 | 861 | if (offset_in_output_section != invalid_address) |
e09ad04a ILT |
862 | new_offset -= offset_in_output_section; |
863 | } | |
6be6f3bd | 864 | |
6a74a719 | 865 | reloc_write.put_r_offset(new_offset); |
4d625b70 | 866 | Classify_reloc::put_r_info(&reloc_write, &reloc, new_symndx); |
6a74a719 ILT |
867 | |
868 | // Handle the reloc addend based on the strategy. | |
869 | ||
870 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
871 | { | |
4d625b70 CC |
872 | if (Classify_reloc::sh_type == elfcpp::SHT_RELA) |
873 | Classify_reloc::put_r_addend(&reloc_write, | |
874 | Classify_reloc::get_r_addend(&reloc)); | |
6a74a719 ILT |
875 | } |
876 | else | |
877 | { | |
878 | // The relocation uses a section symbol in the input file. | |
879 | // We are adjusting it to use a section symbol in the output | |
880 | // file. The input section symbol refers to some address in | |
881 | // the input section. We need the relocation in the output | |
882 | // file to refer to that same address. This adjustment to | |
883 | // the addend is the same calculation we use for a simple | |
884 | // absolute relocation for the input section symbol. | |
885 | ||
886 | const Symbol_value<size>* psymval = object->local_symbol(r_sym); | |
887 | ||
888 | unsigned char* padd = view + offset; | |
889 | switch (strategy) | |
890 | { | |
891 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
892 | { | |
893 | typename elfcpp::Elf_types<size>::Elf_Swxword addend; | |
4d625b70 | 894 | addend = Classify_reloc::get_r_addend(&reloc); |
9215b98b AM |
895 | gold_assert(os != NULL); |
896 | addend = psymval->value(object, addend) - os->address(); | |
4d625b70 | 897 | Classify_reloc::put_r_addend(&reloc_write, addend); |
6a74a719 ILT |
898 | } |
899 | break; | |
900 | ||
7019cd25 ILT |
901 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
902 | break; | |
903 | ||
6a74a719 ILT |
904 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
905 | Relocate_functions<size, big_endian>::rel8(padd, object, | |
906 | psymval); | |
907 | break; | |
908 | ||
909 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
910 | Relocate_functions<size, big_endian>::rel16(padd, object, | |
911 | psymval); | |
912 | break; | |
913 | ||
914 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
915 | Relocate_functions<size, big_endian>::rel32(padd, object, | |
916 | psymval); | |
917 | break; | |
918 | ||
919 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
920 | Relocate_functions<size, big_endian>::rel64(padd, object, | |
921 | psymval); | |
922 | break; | |
923 | ||
2c339f71 DK |
924 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
925 | Relocate_functions<size, big_endian>::rel32_unaligned(padd, | |
926 | object, | |
927 | psymval); | |
928 | break; | |
929 | ||
6a74a719 ILT |
930 | default: |
931 | gold_unreachable(); | |
932 | } | |
933 | } | |
934 | ||
935 | pwrite += reloc_size; | |
936 | } | |
937 | ||
938 | gold_assert(static_cast<section_size_type>(pwrite - reloc_view) | |
939 | == reloc_view_size); | |
940 | } | |
941 | ||
61ba1cf9 ILT |
942 | } // End namespace gold. |
943 | ||
944 | #endif // !defined(GOLD_TARGET_RELOC_H) |