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61ba1cf9 ILT |
1 | // target-reloc.h -- target specific relocation support -*- C++ -*- |
2 | ||
0e804863 | 3 | // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 |
62fe925a | 4 | // Free Software Foundation, Inc. |
6cb15b7f ILT |
5 | // Written by Ian Lance Taylor <iant@google.com>. |
6 | ||
7 | // This file is part of gold. | |
8 | ||
9 | // This program is free software; you can redistribute it and/or modify | |
10 | // it under the terms of the GNU General Public License as published by | |
11 | // the Free Software Foundation; either version 3 of the License, or | |
12 | // (at your option) any later version. | |
13 | ||
14 | // This program is distributed in the hope that it will be useful, | |
15 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | // GNU General Public License for more details. | |
18 | ||
19 | // You should have received a copy of the GNU General Public License | |
20 | // along with this program; if not, write to the Free Software | |
21 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
22 | // MA 02110-1301, USA. | |
23 | ||
61ba1cf9 ILT |
24 | #ifndef GOLD_TARGET_RELOC_H |
25 | #define GOLD_TARGET_RELOC_H | |
26 | ||
27 | #include "elfcpp.h" | |
28 | #include "symtab.h" | |
364c7fa5 | 29 | #include "object.h" |
6a74a719 | 30 | #include "reloc.h" |
c06b7b0b | 31 | #include "reloc-types.h" |
61ba1cf9 ILT |
32 | |
33 | namespace gold | |
34 | { | |
35 | ||
6a74a719 ILT |
36 | // This function implements the generic part of reloc scanning. The |
37 | // template parameter Scan must be a class type which provides two | |
38 | // functions: local() and global(). Those functions implement the | |
39 | // machine specific part of scanning. We do it this way to | |
9b547ce6 | 40 | // avoid making a function call for each relocation, and to avoid |
6a74a719 | 41 | // repeating the generic code for each target. |
92e059d8 | 42 | |
ead1e424 ILT |
43 | template<int size, bool big_endian, typename Target_type, int sh_type, |
44 | typename Scan> | |
92e059d8 ILT |
45 | inline void |
46 | scan_relocs( | |
92e059d8 | 47 | Symbol_table* symtab, |
ead1e424 ILT |
48 | Layout* layout, |
49 | Target_type* target, | |
6fa2a40b | 50 | Sized_relobj_file<size, big_endian>* object, |
a3ad94ed | 51 | unsigned int data_shndx, |
92e059d8 ILT |
52 | const unsigned char* prelocs, |
53 | size_t reloc_count, | |
730cdc88 ILT |
54 | Output_section* output_section, |
55 | bool needs_special_offset_handling, | |
92e059d8 | 56 | size_t local_count, |
730cdc88 | 57 | const unsigned char* plocal_syms) |
92e059d8 ILT |
58 | { |
59 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
60 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
61 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
62 | Scan scan; | |
63 | ||
64 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
65 | { | |
66 | Reltype reloc(prelocs); | |
67 | ||
730cdc88 ILT |
68 | if (needs_special_offset_handling |
69 | && !output_section->is_input_address_mapped(object, data_shndx, | |
70 | reloc.get_r_offset())) | |
71 | continue; | |
72 | ||
92e059d8 ILT |
73 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); |
74 | unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
75 | unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
76 | ||
77 | if (r_sym < local_count) | |
78 | { | |
a3ad94ed | 79 | gold_assert(plocal_syms != NULL); |
92e059d8 ILT |
80 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms |
81 | + r_sym * sym_size); | |
d491d34e ILT |
82 | unsigned int shndx = lsym.get_st_shndx(); |
83 | bool is_ordinary; | |
84 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
bfdfa4cd AM |
85 | // If RELOC is a relocation against a local symbol in a |
86 | // section we are discarding then we can ignore it. It will | |
87 | // eventually become a reloc against the value zero. | |
88 | // | |
89 | // FIXME: We should issue a warning if this is an | |
90 | // allocated section; is this the best place to do it? | |
62fe925a | 91 | // |
bfdfa4cd AM |
92 | // FIXME: The old GNU linker would in some cases look |
93 | // for the linkonce section which caused this section to | |
94 | // be discarded, and, if the other section was the same | |
95 | // size, change the reloc to refer to the other section. | |
96 | // That seems risky and weird to me, and I don't know of | |
97 | // any case where it is actually required. | |
98 | bool is_discarded = (is_ordinary | |
99 | && shndx != elfcpp::SHN_UNDEF | |
100 | && !object->is_section_included(shndx) | |
101 | && !symtab->is_section_folded(object, shndx)); | |
ad0f2072 | 102 | scan.local(symtab, layout, target, object, data_shndx, |
bfdfa4cd | 103 | output_section, reloc, r_type, lsym, is_discarded); |
92e059d8 ILT |
104 | } |
105 | else | |
106 | { | |
730cdc88 | 107 | Symbol* gsym = object->global_symbol(r_sym); |
a3ad94ed | 108 | gold_assert(gsym != NULL); |
92e059d8 ILT |
109 | if (gsym->is_forwarder()) |
110 | gsym = symtab->resolve_forwards(gsym); | |
111 | ||
ad0f2072 | 112 | scan.global(symtab, layout, target, object, data_shndx, |
07f397ab | 113 | output_section, reloc, r_type, gsym); |
92e059d8 ILT |
114 | } |
115 | } | |
116 | } | |
117 | ||
e94cf127 CC |
118 | // Behavior for relocations to discarded comdat sections. |
119 | ||
120 | enum Comdat_behavior | |
121 | { | |
122 | CB_UNDETERMINED, // Not yet determined -- need to look at section name. | |
123 | CB_PRETEND, // Attempt to map to the corresponding kept section. | |
124 | CB_IGNORE, // Ignore the relocation. | |
125 | CB_WARNING // Print a warning. | |
126 | }; | |
127 | ||
168a4726 | 128 | class Default_comdat_behavior |
e94cf127 | 129 | { |
168a4726 AM |
130 | public: |
131 | // Decide what the linker should do for relocations that refer to | |
132 | // discarded comdat sections. This decision is based on the name of | |
133 | // the section being relocated. | |
134 | ||
135 | inline Comdat_behavior | |
136 | get(const char* name) | |
137 | { | |
138 | if (Layout::is_debug_info_section(name)) | |
139 | return CB_PRETEND; | |
140 | if (strcmp(name, ".eh_frame") == 0 | |
141 | || strcmp(name, ".gcc_except_table") == 0) | |
142 | return CB_IGNORE; | |
143 | return CB_WARNING; | |
144 | } | |
145 | }; | |
e94cf127 | 146 | |
837504c4 ILT |
147 | // Give an error for a symbol with non-default visibility which is not |
148 | // defined locally. | |
149 | ||
150 | inline void | |
151 | visibility_error(const Symbol* sym) | |
152 | { | |
153 | const char* v; | |
154 | switch (sym->visibility()) | |
155 | { | |
156 | case elfcpp::STV_INTERNAL: | |
157 | v = _("internal"); | |
158 | break; | |
159 | case elfcpp::STV_HIDDEN: | |
160 | v = _("hidden"); | |
161 | break; | |
162 | case elfcpp::STV_PROTECTED: | |
163 | v = _("protected"); | |
164 | break; | |
165 | default: | |
166 | gold_unreachable(); | |
167 | } | |
168 | gold_error(_("%s symbol '%s' is not defined locally"), | |
169 | v, sym->name()); | |
170 | } | |
171 | ||
191f1a2d ILT |
172 | // Return true if we are should issue an error saying that SYM is an |
173 | // undefined symbol. This is called if there is a relocation against | |
174 | // SYM. | |
175 | ||
176 | inline bool | |
177 | issue_undefined_symbol_error(const Symbol* sym) | |
178 | { | |
beabb2c6 ILT |
179 | // We only report global symbols. |
180 | if (sym == NULL) | |
181 | return false; | |
182 | ||
183 | // We only report undefined symbols. | |
184 | if (!sym->is_undefined() && !sym->is_placeholder()) | |
185 | return false; | |
186 | ||
187 | // We don't report weak symbols. | |
188 | if (sym->binding() == elfcpp::STB_WEAK) | |
189 | return false; | |
190 | ||
191 | // We don't report symbols defined in discarded sections. | |
192 | if (sym->is_defined_in_discarded_section()) | |
193 | return false; | |
194 | ||
195 | // If the target defines this symbol, don't report it here. | |
196 | if (parameters->target().is_defined_by_abi(sym)) | |
197 | return false; | |
198 | ||
199 | // See if we've been told to ignore whether this symbol is | |
200 | // undefined. | |
201 | const char* const u = parameters->options().unresolved_symbols(); | |
202 | if (u != NULL) | |
203 | { | |
204 | if (strcmp(u, "ignore-all") == 0) | |
205 | return false; | |
e2153196 ILT |
206 | if (strcmp(u, "report-all") == 0) |
207 | return true; | |
beabb2c6 ILT |
208 | if (strcmp(u, "ignore-in-object-files") == 0 && !sym->in_dyn()) |
209 | return false; | |
210 | if (strcmp(u, "ignore-in-shared-libs") == 0 && !sym->in_reg()) | |
211 | return false; | |
212 | } | |
213 | ||
214 | // When creating a shared library, only report unresolved symbols if | |
215 | // -z defs was used. | |
216 | if (parameters->options().shared() && !parameters->options().defs()) | |
217 | return false; | |
218 | ||
219 | // Otherwise issue a warning. | |
220 | return true; | |
191f1a2d ILT |
221 | } |
222 | ||
92e059d8 | 223 | // This function implements the generic part of relocation processing. |
6a74a719 ILT |
224 | // The template parameter Relocate must be a class type which provides |
225 | // a single function, relocate(), which implements the machine | |
226 | // specific part of a relocation. | |
61ba1cf9 | 227 | |
168a4726 AM |
228 | // The template parameter Relocate_comdat_behavior is a class type |
229 | // which provides a single function, get(), which determines what the | |
230 | // linker should do for relocations that refer to discarded comdat | |
231 | // sections. | |
232 | ||
61ba1cf9 | 233 | // SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of |
92e059d8 ILT |
234 | // the data. SH_TYPE is the section type: SHT_REL or SHT_RELA. |
235 | // RELOCATE implements operator() to do a relocation. | |
61ba1cf9 | 236 | |
92e059d8 | 237 | // PRELOCS points to the relocation data. RELOC_COUNT is the number |
730cdc88 ILT |
238 | // of relocs. OUTPUT_SECTION is the output section. |
239 | // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be | |
240 | // mapped to output offsets. | |
241 | ||
242 | // VIEW is the section data, VIEW_ADDRESS is its memory address, and | |
243 | // VIEW_SIZE is the size. These refer to the input section, unless | |
244 | // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to | |
245 | // the output section. | |
61ba1cf9 | 246 | |
364c7fa5 ILT |
247 | // RELOC_SYMBOL_CHANGES is used for -fsplit-stack support. If it is |
248 | // not NULL, it is a vector indexed by relocation index. If that | |
249 | // entry is not NULL, it points to a global symbol which used as the | |
250 | // symbol for the relocation, ignoring the symbol index in the | |
251 | // relocation. | |
252 | ||
ead1e424 | 253 | template<int size, bool big_endian, typename Target_type, int sh_type, |
168a4726 AM |
254 | typename Relocate, |
255 | typename Relocate_comdat_behavior> | |
61ba1cf9 ILT |
256 | inline void |
257 | relocate_section( | |
92e059d8 | 258 | const Relocate_info<size, big_endian>* relinfo, |
ead1e424 | 259 | Target_type* target, |
61ba1cf9 ILT |
260 | const unsigned char* prelocs, |
261 | size_t reloc_count, | |
730cdc88 ILT |
262 | Output_section* output_section, |
263 | bool needs_special_offset_handling, | |
61ba1cf9 ILT |
264 | unsigned char* view, |
265 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, | |
364c7fa5 ILT |
266 | section_size_type view_size, |
267 | const Reloc_symbol_changes* reloc_symbol_changes) | |
61ba1cf9 ILT |
268 | { |
269 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
270 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
271 | Relocate relocate; | |
168a4726 | 272 | Relocate_comdat_behavior relocate_comdat_behavior; |
61ba1cf9 | 273 | |
6fa2a40b | 274 | Sized_relobj_file<size, big_endian>* object = relinfo->object; |
730cdc88 | 275 | unsigned int local_count = object->local_symbol_count(); |
92e059d8 | 276 | |
e94cf127 CC |
277 | Comdat_behavior comdat_behavior = CB_UNDETERMINED; |
278 | ||
61ba1cf9 ILT |
279 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) |
280 | { | |
281 | Reltype reloc(prelocs); | |
282 | ||
fe8718a4 ILT |
283 | section_offset_type offset = |
284 | convert_to_section_size_type(reloc.get_r_offset()); | |
61ba1cf9 | 285 | |
730cdc88 ILT |
286 | if (needs_special_offset_handling) |
287 | { | |
288 | offset = output_section->output_offset(relinfo->object, | |
289 | relinfo->data_shndx, | |
290 | offset); | |
291 | if (offset == -1) | |
292 | continue; | |
293 | } | |
294 | ||
61ba1cf9 ILT |
295 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); |
296 | unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
297 | unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
298 | ||
c06b7b0b | 299 | const Sized_symbol<size>* sym; |
61ba1cf9 | 300 | |
b8e6aad9 ILT |
301 | Symbol_value<size> symval; |
302 | const Symbol_value<size> *psymval; | |
880cd20d ILT |
303 | bool is_defined_in_discarded_section; |
304 | unsigned int shndx; | |
364c7fa5 ILT |
305 | if (r_sym < local_count |
306 | && (reloc_symbol_changes == NULL | |
307 | || (*reloc_symbol_changes)[i] == NULL)) | |
61ba1cf9 ILT |
308 | { |
309 | sym = NULL; | |
730cdc88 | 310 | psymval = object->local_symbol(r_sym); |
e94cf127 CC |
311 | |
312 | // If the local symbol belongs to a section we are discarding, | |
313 | // and that section is a debug section, try to find the | |
314 | // corresponding kept section and map this symbol to its | |
62fe925a | 315 | // counterpart in the kept section. The symbol must not |
ef15dade | 316 | // correspond to a section we are folding. |
e94cf127 | 317 | bool is_ordinary; |
880cd20d ILT |
318 | shndx = psymval->input_shndx(&is_ordinary); |
319 | is_defined_in_discarded_section = | |
320 | (is_ordinary | |
321 | && shndx != elfcpp::SHN_UNDEF | |
322 | && !object->is_section_included(shndx) | |
323 | && !relinfo->symtab->is_section_folded(object, shndx)); | |
61ba1cf9 ILT |
324 | } |
325 | else | |
326 | { | |
364c7fa5 ILT |
327 | const Symbol* gsym; |
328 | if (reloc_symbol_changes != NULL | |
329 | && (*reloc_symbol_changes)[i] != NULL) | |
330 | gsym = (*reloc_symbol_changes)[i]; | |
331 | else | |
332 | { | |
333 | gsym = object->global_symbol(r_sym); | |
334 | gold_assert(gsym != NULL); | |
335 | if (gsym->is_forwarder()) | |
336 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
337 | } | |
61ba1cf9 | 338 | |
c06b7b0b | 339 | sym = static_cast<const Sized_symbol<size>*>(gsym); |
d3bbad62 | 340 | if (sym->has_symtab_index() && sym->symtab_index() != -1U) |
b8e6aad9 ILT |
341 | symval.set_output_symtab_index(sym->symtab_index()); |
342 | else | |
343 | symval.set_no_output_symtab_entry(); | |
344 | symval.set_output_value(sym->value()); | |
7223e9ca ILT |
345 | if (gsym->type() == elfcpp::STT_TLS) |
346 | symval.set_is_tls_symbol(); | |
347 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
348 | symval.set_is_ifunc_symbol(); | |
b8e6aad9 | 349 | psymval = &symval; |
880cd20d ILT |
350 | |
351 | is_defined_in_discarded_section = | |
352 | (gsym->is_defined_in_discarded_section() | |
353 | && gsym->is_undefined()); | |
354 | shndx = 0; | |
355 | } | |
356 | ||
357 | Symbol_value<size> symval2; | |
358 | if (is_defined_in_discarded_section) | |
359 | { | |
360 | if (comdat_behavior == CB_UNDETERMINED) | |
361 | { | |
362 | std::string name = object->section_name(relinfo->data_shndx); | |
168a4726 | 363 | comdat_behavior = relocate_comdat_behavior.get(name.c_str()); |
880cd20d ILT |
364 | } |
365 | if (comdat_behavior == CB_PRETEND) | |
366 | { | |
367 | // FIXME: This case does not work for global symbols. | |
368 | // We have no place to store the original section index. | |
369 | // Fortunately this does not matter for comdat sections, | |
370 | // only for sections explicitly discarded by a linker | |
371 | // script. | |
372 | bool found; | |
373 | typename elfcpp::Elf_types<size>::Elf_Addr value = | |
374 | object->map_to_kept_section(shndx, &found); | |
375 | if (found) | |
376 | symval2.set_output_value(value + psymval->input_value()); | |
377 | else | |
378 | symval2.set_output_value(0); | |
379 | } | |
380 | else | |
381 | { | |
382 | if (comdat_behavior == CB_WARNING) | |
383 | gold_warning_at_location(relinfo, i, offset, | |
384 | _("relocation refers to discarded " | |
385 | "section")); | |
386 | symval2.set_output_value(0); | |
387 | } | |
388 | symval2.set_no_output_symtab_entry(); | |
389 | psymval = &symval2; | |
ead1e424 | 390 | } |
61ba1cf9 | 391 | |
0e804863 ILT |
392 | // If OFFSET is out of range, still let the target decide to |
393 | // ignore the relocation. Pass in NULL as the VIEW argument so | |
394 | // that it can return quickly without trashing an invalid memory | |
395 | // address. | |
396 | unsigned char *v = view + offset; | |
397 | if (offset < 0 || static_cast<section_size_type>(offset) >= view_size) | |
398 | v = NULL; | |
399 | ||
031cdbed | 400 | if (!relocate.relocate(relinfo, target, output_section, i, reloc, |
0e804863 ILT |
401 | r_type, sym, psymval, v, view_address + offset, |
402 | view_size)) | |
ead1e424 ILT |
403 | continue; |
404 | ||
0e804863 | 405 | if (v == NULL) |
ead1e424 | 406 | { |
75f2446e ILT |
407 | gold_error_at_location(relinfo, i, offset, |
408 | _("reloc has bad offset %zu"), | |
409 | static_cast<size_t>(offset)); | |
410 | continue; | |
61ba1cf9 ILT |
411 | } |
412 | ||
191f1a2d | 413 | if (issue_undefined_symbol_error(sym)) |
93acabad CC |
414 | { |
415 | gold_undefined_symbol_at_location(sym, relinfo, i, offset); | |
416 | if (sym->is_cxx_vtable()) | |
417 | gold_info(_("%s: the vtable symbol may be undefined because " | |
418 | "the class is missing its key function"), | |
419 | program_name); | |
420 | } | |
837504c4 ILT |
421 | else if (sym != NULL |
422 | && sym->visibility() != elfcpp::STV_DEFAULT | |
423 | && (sym->is_undefined() || sym->is_from_dynobj())) | |
424 | visibility_error(sym); | |
f6ce93d6 ILT |
425 | |
426 | if (sym != NULL && sym->has_warning()) | |
75f2446e | 427 | relinfo->symtab->issue_warning(sym, relinfo, i, offset); |
61ba1cf9 ILT |
428 | } |
429 | } | |
430 | ||
94a3fc8b CC |
431 | // Apply an incremental relocation. |
432 | ||
433 | template<int size, bool big_endian, typename Target_type, | |
434 | typename Relocate> | |
435 | void | |
436 | apply_relocation(const Relocate_info<size, big_endian>* relinfo, | |
437 | Target_type* target, | |
438 | typename elfcpp::Elf_types<size>::Elf_Addr r_offset, | |
439 | unsigned int r_type, | |
440 | typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, | |
441 | const Symbol* gsym, | |
442 | unsigned char* view, | |
443 | typename elfcpp::Elf_types<size>::Elf_Addr address, | |
444 | section_size_type view_size) | |
445 | { | |
446 | // Construct the ELF relocation in a temporary buffer. | |
d55525b9 | 447 | const int reloc_size = elfcpp::Elf_sizes<size>::rela_size; |
94a3fc8b | 448 | unsigned char relbuf[reloc_size]; |
d55525b9 L |
449 | elfcpp::Rela<size, big_endian> rel(relbuf); |
450 | elfcpp::Rela_write<size, big_endian> orel(relbuf); | |
94a3fc8b | 451 | orel.put_r_offset(r_offset); |
d55525b9 | 452 | orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type)); |
94a3fc8b CC |
453 | orel.put_r_addend(r_addend); |
454 | ||
455 | // Setup a Symbol_value for the global symbol. | |
d55525b9 L |
456 | const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym); |
457 | Symbol_value<size> symval; | |
94a3fc8b CC |
458 | gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U); |
459 | symval.set_output_symtab_index(sym->symtab_index()); | |
460 | symval.set_output_value(sym->value()); | |
461 | if (gsym->type() == elfcpp::STT_TLS) | |
462 | symval.set_is_tls_symbol(); | |
463 | else if (gsym->type() == elfcpp::STT_GNU_IFUNC) | |
464 | symval.set_is_ifunc_symbol(); | |
465 | ||
466 | Relocate relocate; | |
467 | relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval, | |
468 | view + r_offset, address + r_offset, view_size); | |
469 | } | |
470 | ||
6a74a719 ILT |
471 | // This class may be used as a typical class for the |
472 | // Scan_relocatable_reloc parameter to scan_relocatable_relocs. The | |
473 | // template parameter Classify_reloc must be a class type which | |
474 | // provides a function get_size_for_reloc which returns the number of | |
475 | // bytes to which a reloc applies. This class is intended to capture | |
476 | // the most typical target behaviour, while still permitting targets | |
477 | // to define their own independent class for Scan_relocatable_reloc. | |
478 | ||
479 | template<int sh_type, typename Classify_reloc> | |
480 | class Default_scan_relocatable_relocs | |
481 | { | |
482 | public: | |
483 | // Return the strategy to use for a local symbol which is not a | |
484 | // section symbol, given the relocation type. | |
485 | inline Relocatable_relocs::Reloc_strategy | |
68943102 | 486 | local_non_section_strategy(unsigned int r_type, Relobj*, unsigned int r_sym) |
c2508178 ILT |
487 | { |
488 | // We assume that relocation type 0 is NONE. Targets which are | |
489 | // different must override. | |
68943102 | 490 | if (r_type == 0 && r_sym == 0) |
c2508178 ILT |
491 | return Relocatable_relocs::RELOC_DISCARD; |
492 | return Relocatable_relocs::RELOC_COPY; | |
493 | } | |
6a74a719 ILT |
494 | |
495 | // Return the strategy to use for a local symbol which is a section | |
496 | // symbol, given the relocation type. | |
497 | inline Relocatable_relocs::Reloc_strategy | |
498 | local_section_strategy(unsigned int r_type, Relobj* object) | |
499 | { | |
500 | if (sh_type == elfcpp::SHT_RELA) | |
501 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA; | |
502 | else | |
503 | { | |
504 | Classify_reloc classify; | |
505 | switch (classify.get_size_for_reloc(r_type, object)) | |
506 | { | |
507 | case 0: | |
7019cd25 | 508 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0; |
6a74a719 ILT |
509 | case 1: |
510 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1; | |
511 | case 2: | |
512 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2; | |
513 | case 4: | |
514 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4; | |
515 | case 8: | |
516 | return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8; | |
517 | default: | |
518 | gold_unreachable(); | |
519 | } | |
520 | } | |
521 | } | |
522 | ||
523 | // Return the strategy to use for a global symbol, given the | |
524 | // relocation type, the object, and the symbol index. | |
525 | inline Relocatable_relocs::Reloc_strategy | |
68943102 ILT |
526 | global_strategy(unsigned int, Relobj*, unsigned int) |
527 | { return Relocatable_relocs::RELOC_COPY; } | |
6a74a719 ILT |
528 | }; |
529 | ||
530 | // Scan relocs during a relocatable link. This is a default | |
531 | // definition which should work for most targets. | |
532 | // Scan_relocatable_reloc must name a class type which provides three | |
533 | // functions which return a Relocatable_relocs::Reloc_strategy code: | |
534 | // global_strategy, local_non_section_strategy, and | |
535 | // local_section_strategy. Most targets should be able to use | |
536 | // Default_scan_relocatable_relocs as this class. | |
537 | ||
7019cd25 | 538 | template<int size, bool big_endian, int sh_type, |
6a74a719 ILT |
539 | typename Scan_relocatable_reloc> |
540 | void | |
541 | scan_relocatable_relocs( | |
6a74a719 ILT |
542 | Symbol_table*, |
543 | Layout*, | |
6fa2a40b | 544 | Sized_relobj_file<size, big_endian>* object, |
6a74a719 ILT |
545 | unsigned int data_shndx, |
546 | const unsigned char* prelocs, | |
547 | size_t reloc_count, | |
548 | Output_section* output_section, | |
549 | bool needs_special_offset_handling, | |
550 | size_t local_symbol_count, | |
551 | const unsigned char* plocal_syms, | |
552 | Relocatable_relocs* rr) | |
553 | { | |
554 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; | |
555 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
556 | const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
557 | Scan_relocatable_reloc scan; | |
558 | ||
559 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
560 | { | |
561 | Reltype reloc(prelocs); | |
562 | ||
563 | Relocatable_relocs::Reloc_strategy strategy; | |
564 | ||
565 | if (needs_special_offset_handling | |
566 | && !output_section->is_input_address_mapped(object, data_shndx, | |
567 | reloc.get_r_offset())) | |
568 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
569 | else | |
570 | { | |
571 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = | |
572 | reloc.get_r_info(); | |
573 | const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
574 | const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
575 | ||
576 | if (r_sym >= local_symbol_count) | |
577 | strategy = scan.global_strategy(r_type, object, r_sym); | |
578 | else | |
579 | { | |
580 | gold_assert(plocal_syms != NULL); | |
581 | typename elfcpp::Sym<size, big_endian> lsym(plocal_syms | |
582 | + r_sym * sym_size); | |
d491d34e ILT |
583 | unsigned int shndx = lsym.get_st_shndx(); |
584 | bool is_ordinary; | |
585 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); | |
586 | if (is_ordinary | |
6a74a719 | 587 | && shndx != elfcpp::SHN_UNDEF |
d491d34e | 588 | && !object->is_section_included(shndx)) |
6a74a719 ILT |
589 | { |
590 | // RELOC is a relocation against a local symbol | |
591 | // defined in a section we are discarding. Discard | |
592 | // the reloc. FIXME: Should we issue a warning? | |
593 | strategy = Relocatable_relocs::RELOC_DISCARD; | |
594 | } | |
595 | else if (lsym.get_st_type() != elfcpp::STT_SECTION) | |
68943102 ILT |
596 | strategy = scan.local_non_section_strategy(r_type, object, |
597 | r_sym); | |
6a74a719 ILT |
598 | else |
599 | { | |
600 | strategy = scan.local_section_strategy(r_type, object); | |
601 | if (strategy != Relocatable_relocs::RELOC_DISCARD) | |
ef9beddf | 602 | object->output_section(shndx)->set_needs_symtab_index(); |
6a74a719 | 603 | } |
d3bbad62 ILT |
604 | |
605 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
606 | object->set_must_have_output_symtab_entry(r_sym); | |
6a74a719 ILT |
607 | } |
608 | } | |
609 | ||
610 | rr->set_next_reloc_strategy(strategy); | |
611 | } | |
612 | } | |
613 | ||
7404fe1b AM |
614 | // Relocate relocs. Called for a relocatable link, and for --emit-relocs. |
615 | // This is a default definition which should work for most targets. | |
6a74a719 | 616 | |
7019cd25 | 617 | template<int size, bool big_endian, int sh_type> |
6a74a719 | 618 | void |
7404fe1b | 619 | relocate_relocs( |
6a74a719 ILT |
620 | const Relocate_info<size, big_endian>* relinfo, |
621 | const unsigned char* prelocs, | |
622 | size_t reloc_count, | |
623 | Output_section* output_section, | |
62fe925a | 624 | typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, |
6a74a719 ILT |
625 | const Relocatable_relocs* rr, |
626 | unsigned char* view, | |
6be6f3bd | 627 | typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
5c388529 | 628 | section_size_type view_size, |
6a74a719 ILT |
629 | unsigned char* reloc_view, |
630 | section_size_type reloc_view_size) | |
631 | { | |
ef9beddf | 632 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
6a74a719 ILT |
633 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype; |
634 | typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write | |
635 | Reltype_write; | |
636 | const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size; | |
eff45813 | 637 | const Address invalid_address = static_cast<Address>(0) - 1; |
6a74a719 | 638 | |
6fa2a40b | 639 | Sized_relobj_file<size, big_endian>* const object = relinfo->object; |
6a74a719 ILT |
640 | const unsigned int local_count = object->local_symbol_count(); |
641 | ||
642 | unsigned char* pwrite = reloc_view; | |
643 | ||
644 | for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) | |
645 | { | |
646 | Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i); | |
647 | if (strategy == Relocatable_relocs::RELOC_DISCARD) | |
648 | continue; | |
649 | ||
5c388529 DK |
650 | if (strategy == Relocatable_relocs::RELOC_SPECIAL) |
651 | { | |
652 | // Target wants to handle this relocation. | |
653 | Sized_target<size, big_endian>* target = | |
654 | parameters->sized_target<size, big_endian>(); | |
655 | target->relocate_special_relocatable(relinfo, sh_type, prelocs, | |
656 | i, output_section, | |
657 | offset_in_output_section, | |
658 | view, view_address, | |
659 | view_size, pwrite); | |
660 | pwrite += reloc_size; | |
661 | continue; | |
662 | } | |
6a74a719 ILT |
663 | Reltype reloc(prelocs); |
664 | Reltype_write reloc_write(pwrite); | |
665 | ||
666 | typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info(); | |
667 | const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info); | |
668 | const unsigned int r_type = elfcpp::elf_r_type<size>(r_info); | |
669 | ||
670 | // Get the new symbol index. | |
671 | ||
672 | unsigned int new_symndx; | |
673 | if (r_sym < local_count) | |
674 | { | |
675 | switch (strategy) | |
676 | { | |
677 | case Relocatable_relocs::RELOC_COPY: | |
818bf354 ILT |
678 | if (r_sym == 0) |
679 | new_symndx = 0; | |
680 | else | |
681 | { | |
682 | new_symndx = object->symtab_index(r_sym); | |
683 | gold_assert(new_symndx != -1U); | |
684 | } | |
6a74a719 ILT |
685 | break; |
686 | ||
687 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
7019cd25 | 688 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
6a74a719 ILT |
689 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
690 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
691 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
692 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
2c339f71 | 693 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
6a74a719 ILT |
694 | { |
695 | // We are adjusting a section symbol. We need to find | |
696 | // the symbol table index of the section symbol for | |
697 | // the output section corresponding to input section | |
698 | // in which this symbol is defined. | |
699 | gold_assert(r_sym < local_count); | |
d491d34e ILT |
700 | bool is_ordinary; |
701 | unsigned int shndx = | |
702 | object->local_symbol_input_shndx(r_sym, &is_ordinary); | |
703 | gold_assert(is_ordinary); | |
ef9beddf | 704 | Output_section* os = object->output_section(shndx); |
6a74a719 ILT |
705 | gold_assert(os != NULL); |
706 | gold_assert(os->needs_symtab_index()); | |
707 | new_symndx = os->symtab_index(); | |
708 | } | |
709 | break; | |
710 | ||
711 | default: | |
712 | gold_unreachable(); | |
713 | } | |
714 | } | |
715 | else | |
716 | { | |
717 | const Symbol* gsym = object->global_symbol(r_sym); | |
718 | gold_assert(gsym != NULL); | |
719 | if (gsym->is_forwarder()) | |
720 | gsym = relinfo->symtab->resolve_forwards(gsym); | |
721 | ||
722 | gold_assert(gsym->has_symtab_index()); | |
723 | new_symndx = gsym->symtab_index(); | |
724 | } | |
725 | ||
726 | // Get the new offset--the location in the output section where | |
727 | // this relocation should be applied. | |
728 | ||
ef9beddf ILT |
729 | Address offset = reloc.get_r_offset(); |
730 | Address new_offset; | |
eff45813 | 731 | if (offset_in_output_section != invalid_address) |
6a74a719 ILT |
732 | new_offset = offset + offset_in_output_section; |
733 | else | |
734 | { | |
ef9beddf ILT |
735 | section_offset_type sot_offset = |
736 | convert_types<section_offset_type, Address>(offset); | |
737 | section_offset_type new_sot_offset = | |
738 | output_section->output_offset(object, relinfo->data_shndx, | |
739 | sot_offset); | |
740 | gold_assert(new_sot_offset != -1); | |
741 | new_offset = new_sot_offset; | |
6a74a719 ILT |
742 | } |
743 | ||
6be6f3bd ILT |
744 | // In an object file, r_offset is an offset within the section. |
745 | // In an executable or dynamic object, generated by | |
746 | // --emit-relocs, r_offset is an absolute address. | |
747 | if (!parameters->options().relocatable()) | |
e09ad04a ILT |
748 | { |
749 | new_offset += view_address; | |
eff45813 | 750 | if (offset_in_output_section != invalid_address) |
e09ad04a ILT |
751 | new_offset -= offset_in_output_section; |
752 | } | |
6be6f3bd | 753 | |
6a74a719 ILT |
754 | reloc_write.put_r_offset(new_offset); |
755 | reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type)); | |
756 | ||
757 | // Handle the reloc addend based on the strategy. | |
758 | ||
759 | if (strategy == Relocatable_relocs::RELOC_COPY) | |
760 | { | |
761 | if (sh_type == elfcpp::SHT_RELA) | |
762 | Reloc_types<sh_type, size, big_endian>:: | |
763 | copy_reloc_addend(&reloc_write, | |
764 | &reloc); | |
765 | } | |
766 | else | |
767 | { | |
768 | // The relocation uses a section symbol in the input file. | |
769 | // We are adjusting it to use a section symbol in the output | |
770 | // file. The input section symbol refers to some address in | |
771 | // the input section. We need the relocation in the output | |
772 | // file to refer to that same address. This adjustment to | |
773 | // the addend is the same calculation we use for a simple | |
774 | // absolute relocation for the input section symbol. | |
775 | ||
776 | const Symbol_value<size>* psymval = object->local_symbol(r_sym); | |
777 | ||
778 | unsigned char* padd = view + offset; | |
779 | switch (strategy) | |
780 | { | |
781 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA: | |
782 | { | |
783 | typename elfcpp::Elf_types<size>::Elf_Swxword addend; | |
784 | addend = Reloc_types<sh_type, size, big_endian>:: | |
785 | get_reloc_addend(&reloc); | |
786 | addend = psymval->value(object, addend); | |
787 | Reloc_types<sh_type, size, big_endian>:: | |
788 | set_reloc_addend(&reloc_write, addend); | |
789 | } | |
790 | break; | |
791 | ||
7019cd25 ILT |
792 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0: |
793 | break; | |
794 | ||
6a74a719 ILT |
795 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1: |
796 | Relocate_functions<size, big_endian>::rel8(padd, object, | |
797 | psymval); | |
798 | break; | |
799 | ||
800 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2: | |
801 | Relocate_functions<size, big_endian>::rel16(padd, object, | |
802 | psymval); | |
803 | break; | |
804 | ||
805 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4: | |
806 | Relocate_functions<size, big_endian>::rel32(padd, object, | |
807 | psymval); | |
808 | break; | |
809 | ||
810 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8: | |
811 | Relocate_functions<size, big_endian>::rel64(padd, object, | |
812 | psymval); | |
813 | break; | |
814 | ||
2c339f71 DK |
815 | case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED: |
816 | Relocate_functions<size, big_endian>::rel32_unaligned(padd, | |
817 | object, | |
818 | psymval); | |
819 | break; | |
820 | ||
6a74a719 ILT |
821 | default: |
822 | gold_unreachable(); | |
823 | } | |
824 | } | |
825 | ||
826 | pwrite += reloc_size; | |
827 | } | |
828 | ||
829 | gold_assert(static_cast<section_size_type>(pwrite - reloc_view) | |
830 | == reloc_view_size); | |
831 | } | |
832 | ||
61ba1cf9 ILT |
833 | } // End namespace gold. |
834 | ||
835 | #endif // !defined(GOLD_TARGET_RELOC_H) |