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61ba1cf9 ILT |
1 | // target-reloc.h -- target specific relocation support -*- C++ -*- |
2 | ||
191f1a2d | 3 | // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 | |
ead1e424 ILT |
42 | template<int size, bool big_endian, typename Target_type, int sh_type, |
43 | typename Scan> | |
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 ILT |
57 | { |
58 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
59 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
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 | ||
92e059d8 ILT |
72 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); |
73 | unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
74 | unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
75 | ||
76 | if (r_sym < local_count) | |
77 | { | |
a3ad94ed | 78 | gold_assert(plocal_syms != NULL); |
92e059d8 ILT |
79 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms |
80 | + r_sym * sym_size); | |
d491d34e ILT |
81 | unsigned int shndx = lsym.get_st_shndx(); |
82 | bool is_ordinary; | |
83 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
bfdfa4cd AM |
84 | // If RELOC is a relocation against a local symbol in a |
85 | // section we are discarding then we can ignore it. It will | |
86 | // eventually become a reloc against the value zero. | |
87 | // | |
88 | // FIXME: We should issue a warning if this is an | |
89 | // allocated section; is this the best place to do it? | |
90 | // | |
91 | // FIXME: The old GNU linker would in some cases look | |
92 | // for the linkonce section which caused this section to | |
93 | // be discarded, and, if the other section was the same | |
94 | // size, change the reloc to refer to the other section. | |
95 | // That seems risky and weird to me, and I don't know of | |
96 | // any case where it is actually required. | |
97 | bool is_discarded = (is_ordinary | |
98 | && shndx != elfcpp::SHN_UNDEF | |
99 | && !object->is_section_included(shndx) | |
100 | && !symtab->is_section_folded(object, shndx)); | |
ad0f2072 | 101 | scan.local(symtab, layout, target, object, data_shndx, |
bfdfa4cd | 102 | output_section, reloc, r_type, lsym, is_discarded); |
92e059d8 ILT |
103 | } |
104 | else | |
105 | { | |
730cdc88 | 106 | Symbol* gsym = object->global_symbol(r_sym); |
a3ad94ed | 107 | gold_assert(gsym != NULL); |
92e059d8 ILT |
108 | if (gsym->is_forwarder()) |
109 | gsym = symtab->resolve_forwards(gsym); | |
110 | ||
ad0f2072 | 111 | scan.global(symtab, layout, target, object, data_shndx, |
07f397ab | 112 | output_section, reloc, r_type, gsym); |
92e059d8 ILT |
113 | } |
114 | } | |
115 | } | |
116 | ||
e94cf127 CC |
117 | // Behavior for relocations to discarded comdat sections. |
118 | ||
119 | enum Comdat_behavior | |
120 | { | |
121 | CB_UNDETERMINED, // Not yet determined -- need to look at section name. | |
122 | CB_PRETEND, // Attempt to map to the corresponding kept section. | |
123 | CB_IGNORE, // Ignore the relocation. | |
124 | CB_WARNING // Print a warning. | |
125 | }; | |
126 | ||
127 | // Decide what the linker should do for relocations that refer to discarded | |
128 | // comdat sections. This decision is based on the name of the section being | |
129 | // relocated. | |
130 | ||
131 | inline Comdat_behavior | |
132 | get_comdat_behavior(const char* name) | |
133 | { | |
134 | if (Layout::is_debug_info_section(name)) | |
135 | return CB_PRETEND; | |
136 | if (strcmp(name, ".eh_frame") == 0 | |
137 | || strcmp(name, ".gcc_except_table") == 0) | |
138 | return CB_IGNORE; | |
139 | return CB_WARNING; | |
140 | } | |
141 | ||
837504c4 ILT |
142 | // Give an error for a symbol with non-default visibility which is not |
143 | // defined locally. | |
144 | ||
145 | inline void | |
146 | visibility_error(const Symbol* sym) | |
147 | { | |
148 | const char* v; | |
149 | switch (sym->visibility()) | |
150 | { | |
151 | case elfcpp::STV_INTERNAL: | |
152 | v = _("internal"); | |
153 | break; | |
154 | case elfcpp::STV_HIDDEN: | |
155 | v = _("hidden"); | |
156 | break; | |
157 | case elfcpp::STV_PROTECTED: | |
158 | v = _("protected"); | |
159 | break; | |
160 | default: | |
161 | gold_unreachable(); | |
162 | } | |
163 | gold_error(_("%s symbol '%s' is not defined locally"), | |
164 | v, sym->name()); | |
165 | } | |
166 | ||
191f1a2d ILT |
167 | // Return true if we are should issue an error saying that SYM is an |
168 | // undefined symbol. This is called if there is a relocation against | |
169 | // SYM. | |
170 | ||
171 | inline bool | |
172 | issue_undefined_symbol_error(const Symbol* sym) | |
173 | { | |
beabb2c6 ILT |
174 | // We only report global symbols. |
175 | if (sym == NULL) | |
176 | return false; | |
177 | ||
178 | // We only report undefined symbols. | |
179 | if (!sym->is_undefined() && !sym->is_placeholder()) | |
180 | return false; | |
181 | ||
182 | // We don't report weak symbols. | |
183 | if (sym->binding() == elfcpp::STB_WEAK) | |
184 | return false; | |
185 | ||
186 | // We don't report symbols defined in discarded sections. | |
187 | if (sym->is_defined_in_discarded_section()) | |
188 | return false; | |
189 | ||
190 | // If the target defines this symbol, don't report it here. | |
191 | if (parameters->target().is_defined_by_abi(sym)) | |
192 | return false; | |
193 | ||
194 | // See if we've been told to ignore whether this symbol is | |
195 | // undefined. | |
196 | const char* const u = parameters->options().unresolved_symbols(); | |
197 | if (u != NULL) | |
198 | { | |
199 | if (strcmp(u, "ignore-all") == 0) | |
200 | return false; | |
e2153196 ILT |
201 | if (strcmp(u, "report-all") == 0) |
202 | return true; | |
beabb2c6 ILT |
203 | if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn()) |
204 | return false; | |
205 | if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg()) | |
206 | return false; | |
207 | } | |
208 | ||
209 | // When creating a shared library, only report unresolved symbols if | |
210 | // -z defs was used. | |
211 | if (parameters->options().shared() && !parameters->options().defs()) | |
212 | return false; | |
213 | ||
214 | // Otherwise issue a warning. | |
215 | return true; | |
191f1a2d ILT |
216 | } |
217 | ||
92e059d8 | 218 | // This function implements the generic part of relocation processing. |
6a74a719 ILT |
219 | // The template parameter Relocate must be a class type which provides |
220 | // a single function, relocate(), which implements the machine | |
221 | // specific part of a relocation. | |
61ba1cf9 ILT |
222 | |
223 | // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of | |
92e059d8 ILT |
224 | // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA. |
225 | // RELOCATE implements operator() to do a relocation. | |
61ba1cf9 | 226 | |
92e059d8 | 227 | // PRELOCS points to the relocation data. RELOC_COUNT is the number |
730cdc88 ILT |
228 | // of relocs. OUTPUT_SECTION is the output section. |
229 | // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be | |
230 | // mapped to output offsets. | |
231 | ||
232 | // VIEW is the section data, VIEW_ADDRESS is its memory address, and | |
233 | // VIEW_SIZE is the size. These refer to the input section, unless | |
234 | // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to | |
235 | // the output section. | |
61ba1cf9 | 236 | |
364c7fa5 ILT |
237 | // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is |
238 | // not NULL, it is a vector indexed by relocation index. If that | |
239 | // entry is not NULL, it points to a global symbol which used as the | |
240 | // symbol for the relocation, ignoring the symbol index in the | |
241 | // relocation. | |
242 | ||
ead1e424 ILT |
243 | template<int size, bool big_endian, typename Target_type, int sh_type, |
244 | typename Relocate> | |
61ba1cf9 ILT |
245 | inline void |
246 | relocate_section( | |
92e059d8 | 247 | const Relocate_info<size, big_endian>* relinfo, |
ead1e424 | 248 | Target_type* target, |
61ba1cf9 ILT |
249 | const unsigned char* prelocs, |
250 | size_t reloc_count, | |
730cdc88 ILT |
251 | Output_section* output_section, |
252 | bool needs_special_offset_handling, | |
61ba1cf9 ILT |
253 | unsigned char* view, |
254 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, | |
364c7fa5 ILT |
255 | section_size_type view_size, |
256 | const Reloc_symbol_changes* reloc_symbol_changes) | |
61ba1cf9 ILT |
257 | { |
258 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
259 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
260 | Relocate relocate; | |
261 | ||
6fa2a40b | 262 | Sized_relobj_file<size, big_endian>* object = relinfo->object; |
730cdc88 | 263 | unsigned int local_count = object->local_symbol_count(); |
92e059d8 | 264 | |
e94cf127 CC |
265 | Comdat_behavior comdat_behavior = CB_UNDETERMINED; |
266 | ||
61ba1cf9 ILT |
267 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) |
268 | { | |
269 | Reltype reloc(prelocs); | |
270 | ||
fe8718a4 ILT |
271 | section_offset_type offset = |
272 | convert_to_section_size_type(reloc.get_r_offset()); | |
61ba1cf9 | 273 | |
730cdc88 ILT |
274 | if (needs_special_offset_handling) |
275 | { | |
276 | offset = output_section->output_offset(relinfo->object, | |
277 | relinfo->data_shndx, | |
278 | offset); | |
279 | if (offset == -1) | |
280 | continue; | |
281 | } | |
282 | ||
61ba1cf9 ILT |
283 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); |
284 | unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
285 | unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
286 | ||
c06b7b0b | 287 | const Sized_symbol<size>* sym; |
61ba1cf9 | 288 | |
b8e6aad9 ILT |
289 | Symbol_value<size> symval; |
290 | const Symbol_value<size> *psymval; | |
880cd20d ILT |
291 | bool is_defined_in_discarded_section; |
292 | unsigned int shndx; | |
364c7fa5 ILT |
293 | if (r_sym < local_count |
294 | && (reloc_symbol_changes == NULL | |
295 | || (*reloc_symbol_changes)[i] == NULL)) | |
61ba1cf9 ILT |
296 | { |
297 | sym = NULL; | |
730cdc88 | 298 | psymval = object->local_symbol(r_sym); |
e94cf127 CC |
299 | |
300 | // If the local symbol belongs to a section we are discarding, | |
301 | // and that section is a debug section, try to find the | |
302 | // corresponding kept section and map this symbol to its | |
ef15dade ST |
303 | // counterpart in the kept section. The symbol must not |
304 | // correspond to a section we are folding. | |
e94cf127 | 305 | bool is_ordinary; |
880cd20d ILT |
306 | shndx = psymval->input_shndx(&is_ordinary); |
307 | is_defined_in_discarded_section = | |
308 | (is_ordinary | |
309 | && shndx != elfcpp::SHN_UNDEF | |
310 | && !object->is_section_included(shndx) | |
311 | && !relinfo->symtab->is_section_folded(object, shndx)); | |
61ba1cf9 ILT |
312 | } |
313 | else | |
314 | { | |
364c7fa5 ILT |
315 | const Symbol* gsym; |
316 | if (reloc_symbol_changes != NULL | |
317 | && (*reloc_symbol_changes)[i] != NULL) | |
318 | gsym = (*reloc_symbol_changes)[i]; | |
319 | else | |
320 | { | |
321 | gsym = object->global_symbol(r_sym); | |
322 | gold_assert(gsym != NULL); | |
323 | if (gsym->is_forwarder()) | |
324 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
325 | } | |
61ba1cf9 | 326 | |
c06b7b0b | 327 | sym = static_cast<const Sized_symbol<size>*>(gsym); |
d3bbad62 | 328 | if (sym->has_symtab_index() && sym->symtab_index() != -1U) |
b8e6aad9 ILT |
329 | symval.set_output_symtab_index(sym->symtab_index()); |
330 | else | |
331 | symval.set_no_output_symtab_entry(); | |
332 | symval.set_output_value(sym->value()); | |
7223e9ca ILT |
333 | if (gsym->type() == elfcpp::STT_TLS) |
334 | symval.set_is_tls_symbol(); | |
335 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
336 | symval.set_is_ifunc_symbol(); | |
b8e6aad9 | 337 | psymval = &symval; |
880cd20d ILT |
338 | |
339 | is_defined_in_discarded_section = | |
340 | (gsym->is_defined_in_discarded_section() | |
341 | && gsym->is_undefined()); | |
342 | shndx = 0; | |
343 | } | |
344 | ||
345 | Symbol_value<size> symval2; | |
346 | if (is_defined_in_discarded_section) | |
347 | { | |
348 | if (comdat_behavior == CB_UNDETERMINED) | |
349 | { | |
350 | std::string name = object->section_name(relinfo->data_shndx); | |
351 | comdat_behavior = get_comdat_behavior(name.c_str()); | |
352 | } | |
353 | if (comdat_behavior == CB_PRETEND) | |
354 | { | |
355 | // FIXME: This case does not work for global symbols. | |
356 | // We have no place to store the original section index. | |
357 | // Fortunately this does not matter for comdat sections, | |
358 | // only for sections explicitly discarded by a linker | |
359 | // script. | |
360 | bool found; | |
361 | typename elfcpp::Elf_types<size>::Elf_Addr value = | |
362 | object->map_to_kept_section(shndx, &found); | |
363 | if (found) | |
364 | symval2.set_output_value(value + psymval->input_value()); | |
365 | else | |
366 | symval2.set_output_value(0); | |
367 | } | |
368 | else | |
369 | { | |
370 | if (comdat_behavior == CB_WARNING) | |
371 | gold_warning_at_location(relinfo, i, offset, | |
372 | _("relocation refers to discarded " | |
373 | "section")); | |
374 | symval2.set_output_value(0); | |
375 | } | |
376 | symval2.set_no_output_symtab_entry(); | |
377 | psymval = &symval2; | |
ead1e424 | 378 | } |
61ba1cf9 | 379 | |
031cdbed ILT |
380 | if (!relocate.relocate(relinfo, target, output_section, i, reloc, |
381 | r_type, sym, psymval, view + offset, | |
382 | view_address + offset, view_size)) | |
ead1e424 ILT |
383 | continue; |
384 | ||
fe8718a4 | 385 | if (offset < 0 || static_cast<section_size_type>(offset) >= view_size) |
ead1e424 | 386 | { |
75f2446e ILT |
387 | gold_error_at_location(relinfo, i, offset, |
388 | _("reloc has bad offset %zu"), | |
389 | static_cast<size_t>(offset)); | |
390 | continue; | |
61ba1cf9 ILT |
391 | } |
392 | ||
191f1a2d | 393 | if (issue_undefined_symbol_error(sym)) |
f073bbf7 | 394 | gold_undefined_symbol_at_location(sym, relinfo, i, offset); |
837504c4 ILT |
395 | else if (sym != NULL |
396 | && sym->visibility() != elfcpp::STV_DEFAULT | |
397 | && (sym->is_undefined() || sym->is_from_dynobj())) | |
398 | visibility_error(sym); | |
f6ce93d6 ILT |
399 | |
400 | if (sym != NULL && sym->has_warning()) | |
75f2446e | 401 | relinfo->symtab->issue_warning(sym, relinfo, i, offset); |
61ba1cf9 ILT |
402 | } |
403 | } | |
404 | ||
94a3fc8b CC |
405 | // Apply an incremental relocation. |
406 | ||
407 | template<int size, bool big_endian, typename Target_type, | |
408 | typename Relocate> | |
409 | void | |
410 | apply_relocation(const Relocate_info<size, big_endian>* relinfo, | |
411 | Target_type* target, | |
412 | typename elfcpp::Elf_types<size>::Elf_Addr r_offset, | |
413 | unsigned int r_type, | |
414 | typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, | |
415 | const Symbol* gsym, | |
416 | unsigned char* view, | |
417 | typename elfcpp::Elf_types<size>::Elf_Addr address, | |
418 | section_size_type view_size) | |
419 | { | |
420 | // Construct the ELF relocation in a temporary buffer. | |
d55525b9 | 421 | const int reloc_size = elfcpp::Elf_sizes<size>::rela_size; |
94a3fc8b | 422 | unsigned char relbuf[reloc_size]; |
d55525b9 L |
423 | elfcpp::Rela<size, big_endian> rel(relbuf); |
424 | elfcpp::Rela_write<size, big_endian> orel(relbuf); | |
94a3fc8b | 425 | orel.put_r_offset(r_offset); |
d55525b9 | 426 | orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type)); |
94a3fc8b CC |
427 | orel.put_r_addend(r_addend); |
428 | ||
429 | // Setup a Symbol_value for the global symbol. | |
d55525b9 L |
430 | const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym); |
431 | Symbol_value<size> symval; | |
94a3fc8b CC |
432 | gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U); |
433 | symval.set_output_symtab_index(sym->symtab_index()); | |
434 | symval.set_output_value(sym->value()); | |
435 | if (gsym->type() == elfcpp::STT_TLS) | |
436 | symval.set_is_tls_symbol(); | |
437 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
438 | symval.set_is_ifunc_symbol(); | |
439 | ||
440 | Relocate relocate; | |
441 | relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval, | |
442 | view + r_offset, address + r_offset, view_size); | |
443 | } | |
444 | ||
6a74a719 ILT |
445 | // This class may be used as a typical class for the |
446 | // Scan_relocatable_reloc parameter to scan_relocatable_relocs. The | |
447 | // template parameter Classify_reloc must be a class type which | |
448 | // provides a function get_size_for_reloc which returns the number of | |
449 | // bytes to which a reloc applies. This class is intended to capture | |
450 | // the most typical target behaviour, while still permitting targets | |
451 | // to define their own independent class for Scan_relocatable_reloc. | |
452 | ||
453 | template<int sh_type, typename Classify_reloc> | |
454 | class Default_scan_relocatable_relocs | |
455 | { | |
456 | public: | |
457 | // Return the strategy to use for a local symbol which is not a | |
458 | // section symbol, given the relocation type. | |
459 | inline Relocatable_relocs::Reloc_strategy | |
68943102 | 460 | local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym) |
c2508178 ILT |
461 | { |
462 | // We assume that relocation type 0 is NONE. Targets which are | |
463 | // different must override. | |
68943102 | 464 | if (r_type == 0 && r_sym == 0) |
c2508178 ILT |
465 | return Relocatable_relocs::RELOC_DISCARD; |
466 | return Relocatable_relocs::RELOC_COPY; | |
467 | } | |
6a74a719 ILT |
468 | |
469 | // Return the strategy to use for a local symbol which is a section | |
470 | // symbol, given the relocation type. | |
471 | inline Relocatable_relocs::Reloc_strategy | |
472 | local_section_strategy(unsigned int r_type, Relobj* object) | |
473 | { | |
474 | if (sh_type == elfcpp::SHT_RELA) | |
475 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; | |
476 | else | |
477 | { | |
478 | Classify_reloc classify; | |
479 | switch (classify.get_size_for_reloc(r_type, object)) | |
480 | { | |
481 | case 0: | |
7019cd25 | 482 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; |
6a74a719 ILT |
483 | case 1: |
484 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1; | |
485 | case 2: | |
486 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2; | |
487 | case 4: | |
488 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4; | |
489 | case 8: | |
490 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8; | |
491 | default: | |
492 | gold_unreachable(); | |
493 | } | |
494 | } | |
495 | } | |
496 | ||
497 | // Return the strategy to use for a global symbol, given the | |
498 | // relocation type, the object, and the symbol index. | |
499 | inline Relocatable_relocs::Reloc_strategy | |
68943102 ILT |
500 | global_strategy(unsigned int, Relobj*, unsigned int) |
501 | { return Relocatable_relocs::RELOC_COPY; } | |
6a74a719 ILT |
502 | }; |
503 | ||
504 | // Scan relocs during a relocatable link. This is a default | |
505 | // definition which should work for most targets. | |
506 | // Scan_relocatable_reloc must name a class type which provides three | |
507 | // functions which return a Relocatable_relocs::Reloc_strategy code: | |
508 | // global_strategy, local_non_section_strategy, and | |
509 | // local_section_strategy. Most targets should be able to use | |
510 | // Default_scan_relocatable_relocs as this class. | |
511 | ||
7019cd25 | 512 | template<int size, bool big_endian, int sh_type, |
6a74a719 ILT |
513 | typename Scan_relocatable_reloc> |
514 | void | |
515 | scan_relocatable_relocs( | |
6a74a719 ILT |
516 | Symbol_table*, |
517 | Layout*, | |
6fa2a40b | 518 | Sized_relobj_file<size, big_endian>* object, |
6a74a719 ILT |
519 | unsigned int data_shndx, |
520 | const unsigned char* prelocs, | |
521 | size_t reloc_count, | |
522 | Output_section* output_section, | |
523 | bool needs_special_offset_handling, | |
524 | size_t local_symbol_count, | |
525 | const unsigned char* plocal_syms, | |
526 | Relocatable_relocs* rr) | |
527 | { | |
528 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
529 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
530 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
531 | Scan_relocatable_reloc scan; | |
532 | ||
533 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
534 | { | |
535 | Reltype reloc(prelocs); | |
536 | ||
537 | Relocatable_relocs::Reloc_strategy strategy; | |
538 | ||
539 | if (needs_special_offset_handling | |
540 | && !output_section->is_input_address_mapped(object, data_shndx, | |
541 | reloc.get_r_offset())) | |
542 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
543 | else | |
544 | { | |
545 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = | |
546 | reloc.get_r_info(); | |
547 | const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
548 | const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
549 | ||
550 | if (r_sym >= local_symbol_count) | |
551 | strategy = scan.global_strategy(r_type, object, r_sym); | |
552 | else | |
553 | { | |
554 | gold_assert(plocal_syms != NULL); | |
555 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms | |
556 | + r_sym * sym_size); | |
d491d34e ILT |
557 | unsigned int shndx = lsym.get_st_shndx(); |
558 | bool is_ordinary; | |
559 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
560 | if (is_ordinary | |
6a74a719 | 561 | && shndx != elfcpp::SHN_UNDEF |
d491d34e | 562 | && !object->is_section_included(shndx)) |
6a74a719 ILT |
563 | { |
564 | // RELOC is a relocation against a local symbol | |
565 | // defined in a section we are discarding. Discard | |
566 | // the reloc. FIXME: Should we issue a warning? | |
567 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
568 | } | |
569 | else if (lsym.get_st_type() != elfcpp::STT_SECTION) | |
68943102 ILT |
570 | strategy = scan.local_non_section_strategy(r_type, object, |
571 | r_sym); | |
6a74a719 ILT |
572 | else |
573 | { | |
574 | strategy = scan.local_section_strategy(r_type, object); | |
575 | if (strategy != Relocatable_relocs::RELOC_DISCARD) | |
ef9beddf | 576 | object->output_section(shndx)->set_needs_symtab_index(); |
6a74a719 | 577 | } |
d3bbad62 ILT |
578 | |
579 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
580 | object->set_must_have_output_symtab_entry(r_sym); | |
6a74a719 ILT |
581 | } |
582 | } | |
583 | ||
584 | rr->set_next_reloc_strategy(strategy); | |
585 | } | |
586 | } | |
587 | ||
7404fe1b AM |
588 | // Relocate relocs. Called for a relocatable link, and for --emit-relocs. |
589 | // This is a default definition which should work for most targets. | |
6a74a719 | 590 | |
7019cd25 | 591 | template<int size, bool big_endian, int sh_type> |
6a74a719 | 592 | void |
7404fe1b | 593 | relocate_relocs( |
6a74a719 ILT |
594 | const Relocate_info<size, big_endian>* relinfo, |
595 | const unsigned char* prelocs, | |
596 | size_t reloc_count, | |
597 | Output_section* output_section, | |
ef9beddf | 598 | typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section, |
6a74a719 ILT |
599 | const Relocatable_relocs* rr, |
600 | unsigned char* view, | |
6be6f3bd | 601 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
5c388529 | 602 | section_size_type view_size, |
6a74a719 ILT |
603 | unsigned char* reloc_view, |
604 | section_size_type reloc_view_size) | |
605 | { | |
ef9beddf | 606 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
6a74a719 ILT |
607 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; |
608 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write | |
609 | Reltype_write; | |
610 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
eff45813 | 611 | const Address invalid_address = static_cast<Address>(0) - 1; |
6a74a719 | 612 | |
6fa2a40b | 613 | Sized_relobj_file<size, big_endian>* const object = relinfo->object; |
6a74a719 ILT |
614 | const unsigned int local_count = object->local_symbol_count(); |
615 | ||
616 | unsigned char* pwrite = reloc_view; | |
617 | ||
618 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
619 | { | |
620 | Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i); | |
621 | if (strategy == Relocatable_relocs::RELOC_DISCARD) | |
622 | continue; | |
623 | ||
5c388529 DK |
624 | if (strategy == Relocatable_relocs::RELOC_SPECIAL) |
625 | { | |
626 | // Target wants to handle this relocation. | |
627 | Sized_target<size, big_endian>* target = | |
628 | parameters->sized_target<size, big_endian>(); | |
629 | target->relocate_special_relocatable(relinfo, sh_type, prelocs, | |
630 | i, output_section, | |
631 | offset_in_output_section, | |
632 | view, view_address, | |
633 | view_size, pwrite); | |
634 | pwrite += reloc_size; | |
635 | continue; | |
636 | } | |
6a74a719 ILT |
637 | Reltype reloc(prelocs); |
638 | Reltype_write reloc_write(pwrite); | |
639 | ||
640 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); | |
641 | const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
642 | const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
643 | ||
644 | // Get the new symbol index. | |
645 | ||
646 | unsigned int new_symndx; | |
647 | if (r_sym < local_count) | |
648 | { | |
649 | switch (strategy) | |
650 | { | |
651 | case Relocatable_relocs::RELOC_COPY: | |
818bf354 ILT |
652 | if (r_sym == 0) |
653 | new_symndx = 0; | |
654 | else | |
655 | { | |
656 | new_symndx = object->symtab_index(r_sym); | |
657 | gold_assert(new_symndx != -1U); | |
658 | } | |
6a74a719 ILT |
659 | break; |
660 | ||
661 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
7019cd25 | 662 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
6a74a719 ILT |
663 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
664 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
665 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
666 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
2c339f71 | 667 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
6a74a719 ILT |
668 | { |
669 | // We are adjusting a section symbol. We need to find | |
670 | // the symbol table index of the section symbol for | |
671 | // the output section corresponding to input section | |
672 | // in which this symbol is defined. | |
673 | gold_assert(r_sym < local_count); | |
d491d34e ILT |
674 | bool is_ordinary; |
675 | unsigned int shndx = | |
676 | object->local_symbol_input_shndx(r_sym, &is_ordinary); | |
677 | gold_assert(is_ordinary); | |
ef9beddf | 678 | Output_section* os = object->output_section(shndx); |
6a74a719 ILT |
679 | gold_assert(os != NULL); |
680 | gold_assert(os->needs_symtab_index()); | |
681 | new_symndx = os->symtab_index(); | |
682 | } | |
683 | break; | |
684 | ||
685 | default: | |
686 | gold_unreachable(); | |
687 | } | |
688 | } | |
689 | else | |
690 | { | |
691 | const Symbol* gsym = object->global_symbol(r_sym); | |
692 | gold_assert(gsym != NULL); | |
693 | if (gsym->is_forwarder()) | |
694 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
695 | ||
696 | gold_assert(gsym->has_symtab_index()); | |
697 | new_symndx = gsym->symtab_index(); | |
698 | } | |
699 | ||
700 | // Get the new offset--the location in the output section where | |
701 | // this relocation should be applied. | |
702 | ||
ef9beddf ILT |
703 | Address offset = reloc.get_r_offset(); |
704 | Address new_offset; | |
eff45813 | 705 | if (offset_in_output_section != invalid_address) |
6a74a719 ILT |
706 | new_offset = offset + offset_in_output_section; |
707 | else | |
708 | { | |
ef9beddf ILT |
709 | section_offset_type sot_offset = |
710 | convert_types<section_offset_type, Address>(offset); | |
711 | section_offset_type new_sot_offset = | |
712 | output_section->output_offset(object, relinfo->data_shndx, | |
713 | sot_offset); | |
714 | gold_assert(new_sot_offset != -1); | |
715 | new_offset = new_sot_offset; | |
6a74a719 ILT |
716 | } |
717 | ||
6be6f3bd ILT |
718 | // In an object file, r_offset is an offset within the section. |
719 | // In an executable or dynamic object, generated by | |
720 | // --emit-relocs, r_offset is an absolute address. | |
721 | if (!parameters->options().relocatable()) | |
e09ad04a ILT |
722 | { |
723 | new_offset += view_address; | |
eff45813 | 724 | if (offset_in_output_section != invalid_address) |
e09ad04a ILT |
725 | new_offset -= offset_in_output_section; |
726 | } | |
6be6f3bd | 727 | |
6a74a719 ILT |
728 | reloc_write.put_r_offset(new_offset); |
729 | reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type)); | |
730 | ||
731 | // Handle the reloc addend based on the strategy. | |
732 | ||
733 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
734 | { | |
735 | if (sh_type == elfcpp::SHT_RELA) | |
736 | Reloc_types<sh_type, size, big_endian>:: | |
737 | copy_reloc_addend(&reloc_write, | |
738 | &reloc); | |
739 | } | |
740 | else | |
741 | { | |
742 | // The relocation uses a section symbol in the input file. | |
743 | // We are adjusting it to use a section symbol in the output | |
744 | // file. The input section symbol refers to some address in | |
745 | // the input section. We need the relocation in the output | |
746 | // file to refer to that same address. This adjustment to | |
747 | // the addend is the same calculation we use for a simple | |
748 | // absolute relocation for the input section symbol. | |
749 | ||
750 | const Symbol_value<size>* psymval = object->local_symbol(r_sym); | |
751 | ||
752 | unsigned char* padd = view + offset; | |
753 | switch (strategy) | |
754 | { | |
755 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
756 | { | |
757 | typename elfcpp::Elf_types<size>::Elf_Swxword addend; | |
758 | addend = Reloc_types<sh_type, size, big_endian>:: | |
759 | get_reloc_addend(&reloc); | |
760 | addend = psymval->value(object, addend); | |
761 | Reloc_types<sh_type, size, big_endian>:: | |
762 | set_reloc_addend(&reloc_write, addend); | |
763 | } | |
764 | break; | |
765 | ||
7019cd25 ILT |
766 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
767 | break; | |
768 | ||
6a74a719 ILT |
769 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
770 | Relocate_functions<size, big_endian>::rel8(padd, object, | |
771 | psymval); | |
772 | break; | |
773 | ||
774 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
775 | Relocate_functions<size, big_endian>::rel16(padd, object, | |
776 | psymval); | |
777 | break; | |
778 | ||
779 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
780 | Relocate_functions<size, big_endian>::rel32(padd, object, | |
781 | psymval); | |
782 | break; | |
783 | ||
784 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
785 | Relocate_functions<size, big_endian>::rel64(padd, object, | |
786 | psymval); | |
787 | break; | |
788 | ||
2c339f71 DK |
789 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
790 | Relocate_functions<size, big_endian>::rel32_unaligned(padd, | |
791 | object, | |
792 | psymval); | |
793 | break; | |
794 | ||
6a74a719 ILT |
795 | default: |
796 | gold_unreachable(); | |
797 | } | |
798 | } | |
799 | ||
800 | pwrite += reloc_size; | |
801 | } | |
802 | ||
803 | gold_assert(static_cast<section_size_type>(pwrite - reloc_view) | |
804 | == reloc_view_size); | |
805 | } | |
806 | ||
61ba1cf9 ILT |
807 | } // End namespace gold. |
808 | ||
809 | #endif // !defined(GOLD_TARGET_RELOC_H) |