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4a657b0d DK |
1 | // arm.cc -- arm target support for gold. |
2 | ||
3 | // Copyright 2009 Free Software Foundation, Inc. | |
4 | // Written by Doug Kwan <dougkwan@google.com> based on the i386 code | |
5 | // 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 | ||
24 | #include "gold.h" | |
25 | ||
26 | #include <cstring> | |
27 | #include <limits> | |
28 | #include <cstdio> | |
29 | #include <string> | |
30 | ||
31 | #include "elfcpp.h" | |
32 | #include "parameters.h" | |
33 | #include "reloc.h" | |
34 | #include "arm.h" | |
35 | #include "object.h" | |
36 | #include "symtab.h" | |
37 | #include "layout.h" | |
38 | #include "output.h" | |
39 | #include "copy-relocs.h" | |
40 | #include "target.h" | |
41 | #include "target-reloc.h" | |
42 | #include "target-select.h" | |
43 | #include "tls.h" | |
44 | #include "defstd.h" | |
45 | ||
46 | namespace | |
47 | { | |
48 | ||
49 | using namespace gold; | |
50 | ||
94cdfcff DK |
51 | template<bool big_endian> |
52 | class Output_data_plt_arm; | |
53 | ||
4a657b0d DK |
54 | // The arm target class. |
55 | // | |
56 | // This is a very simple port of gold for ARM-EABI. It is intended for | |
57 | // supporting Android only for the time being. Only these relocation types | |
58 | // are supported. | |
59 | // | |
60 | // R_ARM_NONE | |
61 | // R_ARM_ABS32 | |
62 | // R_ARM_REL32 | |
63 | // R_ARM_THM_CALL | |
64 | // R_ARM_COPY | |
65 | // R_ARM_GLOB_DAT | |
66 | // R_ARM_BASE_PREL | |
67 | // R_ARM_JUMP_SLOT | |
68 | // R_ARM_RELATIVE | |
69 | // R_ARM_GOTOFF32 | |
70 | // R_ARM_GOT_BREL | |
71 | // R_ARM_PLT32 | |
72 | // R_ARM_CALL | |
73 | // R_ARM_JUMP24 | |
74 | // R_ARM_TARGET1 | |
75 | // R_ARM_PREL31 | |
76 | // | |
77 | // Coming soon (pending patches): | |
4a657b0d DK |
78 | // - Local scanner |
79 | // - Global scanner | |
80 | // - Relocation | |
81 | // - Defining section symbols __exidx_start and __exidx_stop. | |
82 | // - Support interworking. | |
83 | // - Mergeing all .ARM.xxx.yyy sections into .ARM.xxx. Currently, they | |
84 | // are incorrectly merged into an .ARM section. | |
85 | // | |
86 | // TODOs: | |
87 | // - Create a PT_ARM_EXIDX program header for a shared object that | |
88 | // might throw an exception. | |
89 | // - Support more relocation types as needed. | |
94cdfcff DK |
90 | // - Make PLTs more flexible for different architecture features like |
91 | // Thumb-2 and BE8. | |
4a657b0d DK |
92 | |
93 | template<bool big_endian> | |
94 | class Target_arm : public Sized_target<32, big_endian> | |
95 | { | |
96 | public: | |
97 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, big_endian> | |
98 | Reloc_section; | |
99 | ||
100 | Target_arm() | |
94cdfcff DK |
101 | : Sized_target<32, big_endian>(&arm_info), |
102 | got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL), | |
103 | copy_relocs_(elfcpp::R_ARM_COPY), dynbss_(NULL) | |
4a657b0d DK |
104 | { } |
105 | ||
106 | // Process the relocations to determine unreferenced sections for | |
107 | // garbage collection. | |
108 | void | |
109 | gc_process_relocs(const General_options& options, | |
110 | Symbol_table* symtab, | |
111 | Layout* layout, | |
112 | Sized_relobj<32, big_endian>* object, | |
113 | unsigned int data_shndx, | |
114 | unsigned int sh_type, | |
115 | const unsigned char* prelocs, | |
116 | size_t reloc_count, | |
117 | Output_section* output_section, | |
118 | bool needs_special_offset_handling, | |
119 | size_t local_symbol_count, | |
120 | const unsigned char* plocal_symbols); | |
121 | ||
122 | // Scan the relocations to look for symbol adjustments. | |
123 | void | |
124 | scan_relocs(const General_options& options, | |
125 | Symbol_table* symtab, | |
126 | Layout* layout, | |
127 | Sized_relobj<32, big_endian>* object, | |
128 | unsigned int data_shndx, | |
129 | unsigned int sh_type, | |
130 | const unsigned char* prelocs, | |
131 | size_t reloc_count, | |
132 | Output_section* output_section, | |
133 | bool needs_special_offset_handling, | |
134 | size_t local_symbol_count, | |
135 | const unsigned char* plocal_symbols); | |
136 | ||
137 | // Finalize the sections. | |
138 | void | |
139 | do_finalize_sections(Layout*); | |
140 | ||
94cdfcff | 141 | // Return the value to use for a dynamic symbol which requires special |
4a657b0d DK |
142 | // treatment. |
143 | uint64_t | |
144 | do_dynsym_value(const Symbol*) const; | |
145 | ||
146 | // Relocate a section. | |
147 | void | |
148 | relocate_section(const Relocate_info<32, big_endian>*, | |
149 | unsigned int sh_type, | |
150 | const unsigned char* prelocs, | |
151 | size_t reloc_count, | |
152 | Output_section* output_section, | |
153 | bool needs_special_offset_handling, | |
154 | unsigned char* view, | |
155 | elfcpp::Elf_types<32>::Elf_Addr view_address, | |
156 | section_size_type view_size); | |
157 | ||
158 | // Scan the relocs during a relocatable link. | |
159 | void | |
160 | scan_relocatable_relocs(const General_options& options, | |
161 | Symbol_table* symtab, | |
162 | Layout* layout, | |
163 | Sized_relobj<32, big_endian>* object, | |
164 | unsigned int data_shndx, | |
165 | unsigned int sh_type, | |
166 | const unsigned char* prelocs, | |
167 | size_t reloc_count, | |
168 | Output_section* output_section, | |
169 | bool needs_special_offset_handling, | |
170 | size_t local_symbol_count, | |
171 | const unsigned char* plocal_symbols, | |
172 | Relocatable_relocs*); | |
173 | ||
174 | // Relocate a section during a relocatable link. | |
175 | void | |
176 | relocate_for_relocatable(const Relocate_info<32, big_endian>*, | |
177 | unsigned int sh_type, | |
178 | const unsigned char* prelocs, | |
179 | size_t reloc_count, | |
180 | Output_section* output_section, | |
181 | off_t offset_in_output_section, | |
182 | const Relocatable_relocs*, | |
183 | unsigned char* view, | |
184 | elfcpp::Elf_types<32>::Elf_Addr view_address, | |
185 | section_size_type view_size, | |
186 | unsigned char* reloc_view, | |
187 | section_size_type reloc_view_size); | |
188 | ||
189 | // Return whether SYM is defined by the ABI. | |
190 | bool | |
191 | do_is_defined_by_abi(Symbol* sym) const | |
192 | { return strcmp(sym->name(), "__tls_get_addr") == 0; } | |
193 | ||
94cdfcff DK |
194 | // Return the size of the GOT section. |
195 | section_size_type | |
196 | got_size() | |
197 | { | |
198 | gold_assert(this->got_ != NULL); | |
199 | return this->got_->data_size(); | |
200 | } | |
201 | ||
4a657b0d DK |
202 | // Map platform-specific reloc types |
203 | static unsigned int | |
204 | get_real_reloc_type (unsigned int r_type); | |
205 | ||
206 | private: | |
207 | // The class which scans relocations. | |
208 | class Scan | |
209 | { | |
210 | public: | |
211 | Scan() | |
212 | { } | |
213 | ||
214 | inline void | |
215 | local(const General_options& options, Symbol_table* symtab, | |
216 | Layout* layout, Target_arm* target, | |
217 | Sized_relobj<32, big_endian>* object, | |
218 | unsigned int data_shndx, | |
219 | Output_section* output_section, | |
220 | const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, | |
221 | const elfcpp::Sym<32, big_endian>& lsym); | |
222 | ||
223 | inline void | |
224 | global(const General_options& options, Symbol_table* symtab, | |
225 | Layout* layout, Target_arm* target, | |
226 | Sized_relobj<32, big_endian>* object, | |
227 | unsigned int data_shndx, | |
228 | Output_section* output_section, | |
229 | const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, | |
230 | Symbol* gsym); | |
231 | ||
232 | private: | |
233 | static void | |
234 | unsupported_reloc_local(Sized_relobj<32, big_endian>*, | |
235 | unsigned int r_type); | |
236 | ||
237 | static void | |
238 | unsupported_reloc_global(Sized_relobj<32, big_endian>*, | |
239 | unsigned int r_type, Symbol*); | |
240 | }; | |
241 | ||
242 | // The class which implements relocation. | |
243 | class Relocate | |
244 | { | |
245 | public: | |
246 | Relocate() | |
247 | { } | |
248 | ||
249 | ~Relocate() | |
250 | { } | |
251 | ||
252 | // Do a relocation. Return false if the caller should not issue | |
253 | // any warnings about this relocation. | |
254 | inline bool | |
255 | relocate(const Relocate_info<32, big_endian>*, Target_arm*, | |
256 | Output_section*, size_t relnum, | |
257 | const elfcpp::Rel<32, big_endian>&, | |
258 | unsigned int r_type, const Sized_symbol<32>*, | |
259 | const Symbol_value<32>*, | |
260 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, | |
261 | section_size_type); | |
262 | }; | |
263 | ||
264 | // A class which returns the size required for a relocation type, | |
265 | // used while scanning relocs during a relocatable link. | |
266 | class Relocatable_size_for_reloc | |
267 | { | |
268 | public: | |
269 | unsigned int | |
270 | get_size_for_reloc(unsigned int, Relobj*); | |
271 | }; | |
272 | ||
94cdfcff DK |
273 | // Get the GOT section, creating it if necessary. |
274 | Output_data_got<32, big_endian>* | |
275 | got_section(Symbol_table*, Layout*); | |
276 | ||
277 | // Get the GOT PLT section. | |
278 | Output_data_space* | |
279 | got_plt_section() const | |
280 | { | |
281 | gold_assert(this->got_plt_ != NULL); | |
282 | return this->got_plt_; | |
283 | } | |
284 | ||
285 | // Create a PLT entry for a global symbol. | |
286 | void | |
287 | make_plt_entry(Symbol_table*, Layout*, Symbol*); | |
288 | ||
289 | // Get the PLT section. | |
290 | const Output_data_plt_arm<big_endian>* | |
291 | plt_section() const | |
292 | { | |
293 | gold_assert(this->plt_ != NULL); | |
294 | return this->plt_; | |
295 | } | |
296 | ||
297 | // Get the dynamic reloc section, creating it if necessary. | |
298 | Reloc_section* | |
299 | rel_dyn_section(Layout*); | |
300 | ||
301 | // Return true if the symbol may need a COPY relocation. | |
302 | // References from an executable object to non-function symbols | |
303 | // defined in a dynamic object may need a COPY relocation. | |
304 | bool | |
305 | may_need_copy_reloc(Symbol* gsym) | |
306 | { | |
307 | return (!parameters->options().shared() | |
308 | && gsym->is_from_dynobj() | |
309 | && gsym->type() != elfcpp::STT_FUNC); | |
310 | } | |
311 | ||
312 | // Add a potential copy relocation. | |
313 | void | |
314 | copy_reloc(Symbol_table* symtab, Layout* layout, | |
315 | Sized_relobj<32, big_endian>* object, | |
316 | unsigned int shndx, Output_section* output_section, | |
317 | Symbol* sym, const elfcpp::Rel<32, big_endian>& reloc) | |
318 | { | |
319 | this->copy_relocs_.copy_reloc(symtab, layout, | |
320 | symtab->get_sized_symbol<32>(sym), | |
321 | object, shndx, output_section, reloc, | |
322 | this->rel_dyn_section(layout)); | |
323 | } | |
324 | ||
4a657b0d DK |
325 | // Information about this specific target which we pass to the |
326 | // general Target structure. | |
327 | static const Target::Target_info arm_info; | |
94cdfcff DK |
328 | |
329 | // The types of GOT entries needed for this platform. | |
330 | enum Got_type | |
331 | { | |
332 | GOT_TYPE_STANDARD = 0 // GOT entry for a regular symbol | |
333 | }; | |
334 | ||
335 | // The GOT section. | |
336 | Output_data_got<32, big_endian>* got_; | |
337 | // The PLT section. | |
338 | Output_data_plt_arm<big_endian>* plt_; | |
339 | // The GOT PLT section. | |
340 | Output_data_space* got_plt_; | |
341 | // The dynamic reloc section. | |
342 | Reloc_section* rel_dyn_; | |
343 | // Relocs saved to avoid a COPY reloc. | |
344 | Copy_relocs<elfcpp::SHT_REL, 32, big_endian> copy_relocs_; | |
345 | // Space for variables copied with a COPY reloc. | |
346 | Output_data_space* dynbss_; | |
4a657b0d DK |
347 | }; |
348 | ||
349 | template<bool big_endian> | |
350 | const Target::Target_info Target_arm<big_endian>::arm_info = | |
351 | { | |
352 | 32, // size | |
353 | big_endian, // is_big_endian | |
354 | elfcpp::EM_ARM, // machine_code | |
355 | false, // has_make_symbol | |
356 | false, // has_resolve | |
357 | false, // has_code_fill | |
358 | true, // is_default_stack_executable | |
359 | '\0', // wrap_char | |
360 | "/usr/lib/libc.so.1", // dynamic_linker | |
361 | 0x8000, // default_text_segment_address | |
362 | 0x1000, // abi_pagesize (overridable by -z max-page-size) | |
363 | 0x1000 // common_pagesize (overridable by -z common-page-size) | |
364 | }; | |
365 | ||
94cdfcff DK |
366 | // Get the GOT section, creating it if necessary. |
367 | ||
368 | template<bool big_endian> | |
369 | Output_data_got<32, big_endian>* | |
370 | Target_arm<big_endian>::got_section(Symbol_table* symtab, Layout* layout) | |
371 | { | |
372 | if (this->got_ == NULL) | |
373 | { | |
374 | gold_assert(symtab != NULL && layout != NULL); | |
375 | ||
376 | this->got_ = new Output_data_got<32, big_endian>(); | |
377 | ||
378 | Output_section* os; | |
379 | os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, | |
380 | (elfcpp::SHF_ALLOC | |
381 | | elfcpp::SHF_WRITE), | |
382 | this->got_); | |
383 | os->set_is_relro(); | |
384 | ||
385 | // The old GNU linker creates a .got.plt section. We just | |
386 | // create another set of data in the .got section. Note that we | |
387 | // always create a PLT if we create a GOT, although the PLT | |
388 | // might be empty. | |
389 | this->got_plt_ = new Output_data_space(4, "** GOT PLT"); | |
390 | os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, | |
391 | (elfcpp::SHF_ALLOC | |
392 | | elfcpp::SHF_WRITE), | |
393 | this->got_plt_); | |
394 | os->set_is_relro(); | |
395 | ||
396 | // The first three entries are reserved. | |
397 | this->got_plt_->set_current_data_size(3 * 4); | |
398 | ||
399 | // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. | |
400 | symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, | |
401 | this->got_plt_, | |
402 | 0, 0, elfcpp::STT_OBJECT, | |
403 | elfcpp::STB_LOCAL, | |
404 | elfcpp::STV_HIDDEN, 0, | |
405 | false, false); | |
406 | } | |
407 | return this->got_; | |
408 | } | |
409 | ||
410 | // Get the dynamic reloc section, creating it if necessary. | |
411 | ||
412 | template<bool big_endian> | |
413 | typename Target_arm<big_endian>::Reloc_section* | |
414 | Target_arm<big_endian>::rel_dyn_section(Layout* layout) | |
415 | { | |
416 | if (this->rel_dyn_ == NULL) | |
417 | { | |
418 | gold_assert(layout != NULL); | |
419 | this->rel_dyn_ = new Reloc_section(parameters->options().combreloc()); | |
420 | layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, | |
421 | elfcpp::SHF_ALLOC, this->rel_dyn_); | |
422 | } | |
423 | return this->rel_dyn_; | |
424 | } | |
425 | ||
426 | // A class to handle the PLT data. | |
427 | ||
428 | template<bool big_endian> | |
429 | class Output_data_plt_arm : public Output_section_data | |
430 | { | |
431 | public: | |
432 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, big_endian> | |
433 | Reloc_section; | |
434 | ||
435 | Output_data_plt_arm(Layout*, Output_data_space*); | |
436 | ||
437 | // Add an entry to the PLT. | |
438 | void | |
439 | add_entry(Symbol* gsym); | |
440 | ||
441 | // Return the .rel.plt section data. | |
442 | const Reloc_section* | |
443 | rel_plt() const | |
444 | { return this->rel_; } | |
445 | ||
446 | protected: | |
447 | void | |
448 | do_adjust_output_section(Output_section* os); | |
449 | ||
450 | // Write to a map file. | |
451 | void | |
452 | do_print_to_mapfile(Mapfile* mapfile) const | |
453 | { mapfile->print_output_data(this, _("** PLT")); } | |
454 | ||
455 | private: | |
456 | // Template for the first PLT entry. | |
457 | static const uint32_t first_plt_entry[5]; | |
458 | ||
459 | // Template for subsequent PLT entries. | |
460 | static const uint32_t plt_entry[3]; | |
461 | ||
462 | // Set the final size. | |
463 | void | |
464 | set_final_data_size() | |
465 | { | |
466 | this->set_data_size(sizeof(first_plt_entry) | |
467 | + this->count_ * sizeof(plt_entry)); | |
468 | } | |
469 | ||
470 | // Write out the PLT data. | |
471 | void | |
472 | do_write(Output_file*); | |
473 | ||
474 | // The reloc section. | |
475 | Reloc_section* rel_; | |
476 | // The .got.plt section. | |
477 | Output_data_space* got_plt_; | |
478 | // The number of PLT entries. | |
479 | unsigned int count_; | |
480 | }; | |
481 | ||
482 | // Create the PLT section. The ordinary .got section is an argument, | |
483 | // since we need to refer to the start. We also create our own .got | |
484 | // section just for PLT entries. | |
485 | ||
486 | template<bool big_endian> | |
487 | Output_data_plt_arm<big_endian>::Output_data_plt_arm(Layout* layout, | |
488 | Output_data_space* got_plt) | |
489 | : Output_section_data(4), got_plt_(got_plt), count_(0) | |
490 | { | |
491 | this->rel_ = new Reloc_section(false); | |
492 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, | |
493 | elfcpp::SHF_ALLOC, this->rel_); | |
494 | } | |
495 | ||
496 | template<bool big_endian> | |
497 | void | |
498 | Output_data_plt_arm<big_endian>::do_adjust_output_section(Output_section* os) | |
499 | { | |
500 | os->set_entsize(0); | |
501 | } | |
502 | ||
503 | // Add an entry to the PLT. | |
504 | ||
505 | template<bool big_endian> | |
506 | void | |
507 | Output_data_plt_arm<big_endian>::add_entry(Symbol* gsym) | |
508 | { | |
509 | gold_assert(!gsym->has_plt_offset()); | |
510 | ||
511 | // Note that when setting the PLT offset we skip the initial | |
512 | // reserved PLT entry. | |
513 | gsym->set_plt_offset((this->count_) * sizeof(plt_entry) | |
514 | + sizeof(first_plt_entry)); | |
515 | ||
516 | ++this->count_; | |
517 | ||
518 | section_offset_type got_offset = this->got_plt_->current_data_size(); | |
519 | ||
520 | // Every PLT entry needs a GOT entry which points back to the PLT | |
521 | // entry (this will be changed by the dynamic linker, normally | |
522 | // lazily when the function is called). | |
523 | this->got_plt_->set_current_data_size(got_offset + 4); | |
524 | ||
525 | // Every PLT entry needs a reloc. | |
526 | gsym->set_needs_dynsym_entry(); | |
527 | this->rel_->add_global(gsym, elfcpp::R_ARM_JUMP_SLOT, this->got_plt_, | |
528 | got_offset); | |
529 | ||
530 | // Note that we don't need to save the symbol. The contents of the | |
531 | // PLT are independent of which symbols are used. The symbols only | |
532 | // appear in the relocations. | |
533 | } | |
534 | ||
535 | // ARM PLTs. | |
536 | // FIXME: This is not very flexible. Right now this has only been tested | |
537 | // on armv5te. If we are to support additional architecture features like | |
538 | // Thumb-2 or BE8, we need to make this more flexible like GNU ld. | |
539 | ||
540 | // The first entry in the PLT. | |
541 | template<bool big_endian> | |
542 | const uint32_t Output_data_plt_arm<big_endian>::first_plt_entry[5] = | |
543 | { | |
544 | 0xe52de004, // str lr, [sp, #-4]! | |
545 | 0xe59fe004, // ldr lr, [pc, #4] | |
546 | 0xe08fe00e, // add lr, pc, lr | |
547 | 0xe5bef008, // ldr pc, [lr, #8]! | |
548 | 0x00000000, // &GOT[0] - . | |
549 | }; | |
550 | ||
551 | // Subsequent entries in the PLT. | |
552 | ||
553 | template<bool big_endian> | |
554 | const uint32_t Output_data_plt_arm<big_endian>::plt_entry[3] = | |
555 | { | |
556 | 0xe28fc600, // add ip, pc, #0xNN00000 | |
557 | 0xe28cca00, // add ip, ip, #0xNN000 | |
558 | 0xe5bcf000, // ldr pc, [ip, #0xNNN]! | |
559 | }; | |
560 | ||
561 | // Write out the PLT. This uses the hand-coded instructions above, | |
562 | // and adjusts them as needed. This is all specified by the arm ELF | |
563 | // Processor Supplement. | |
564 | ||
565 | template<bool big_endian> | |
566 | void | |
567 | Output_data_plt_arm<big_endian>::do_write(Output_file* of) | |
568 | { | |
569 | const off_t offset = this->offset(); | |
570 | const section_size_type oview_size = | |
571 | convert_to_section_size_type(this->data_size()); | |
572 | unsigned char* const oview = of->get_output_view(offset, oview_size); | |
573 | ||
574 | const off_t got_file_offset = this->got_plt_->offset(); | |
575 | const section_size_type got_size = | |
576 | convert_to_section_size_type(this->got_plt_->data_size()); | |
577 | unsigned char* const got_view = of->get_output_view(got_file_offset, | |
578 | got_size); | |
579 | unsigned char* pov = oview; | |
580 | ||
581 | elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); | |
582 | elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); | |
583 | ||
584 | // Write first PLT entry. All but the last word are constants. | |
585 | const size_t num_first_plt_words = (sizeof(first_plt_entry) | |
586 | / sizeof(plt_entry[0])); | |
587 | for (size_t i = 0; i < num_first_plt_words - 1; i++) | |
588 | elfcpp::Swap<32, big_endian>::writeval(pov + i * 4, first_plt_entry[i]); | |
589 | // Last word in first PLT entry is &GOT[0] - . | |
590 | elfcpp::Swap<32, big_endian>::writeval(pov + 16, | |
591 | got_address - (plt_address + 16)); | |
592 | pov += sizeof(first_plt_entry); | |
593 | ||
594 | unsigned char* got_pov = got_view; | |
595 | ||
596 | memset(got_pov, 0, 12); | |
597 | got_pov += 12; | |
598 | ||
599 | const int rel_size = elfcpp::Elf_sizes<32>::rel_size; | |
600 | unsigned int plt_offset = sizeof(first_plt_entry); | |
601 | unsigned int plt_rel_offset = 0; | |
602 | unsigned int got_offset = 12; | |
603 | const unsigned int count = this->count_; | |
604 | for (unsigned int i = 0; | |
605 | i < count; | |
606 | ++i, | |
607 | pov += sizeof(plt_entry), | |
608 | got_pov += 4, | |
609 | plt_offset += sizeof(plt_entry), | |
610 | plt_rel_offset += rel_size, | |
611 | got_offset += 4) | |
612 | { | |
613 | // Set and adjust the PLT entry itself. | |
614 | int32_t offset = ((got_address + got_offset) | |
615 | - (plt_address + plt_offset + 8)); | |
616 | ||
617 | gold_assert(offset >= 0 && offset < 0x0fffffff); | |
618 | uint32_t plt_insn0 = plt_entry[0] | ((offset >> 20) & 0xff); | |
619 | elfcpp::Swap<32, big_endian>::writeval(pov, plt_insn0); | |
620 | uint32_t plt_insn1 = plt_entry[1] | ((offset >> 12) & 0xff); | |
621 | elfcpp::Swap<32, big_endian>::writeval(pov + 4, plt_insn1); | |
622 | uint32_t plt_insn2 = plt_entry[2] | (offset & 0xfff); | |
623 | elfcpp::Swap<32, big_endian>::writeval(pov + 8, plt_insn2); | |
624 | ||
625 | // Set the entry in the GOT. | |
626 | elfcpp::Swap<32, big_endian>::writeval(got_pov, plt_address); | |
627 | } | |
628 | ||
629 | gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); | |
630 | gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); | |
631 | ||
632 | of->write_output_view(offset, oview_size, oview); | |
633 | of->write_output_view(got_file_offset, got_size, got_view); | |
634 | } | |
635 | ||
636 | // Create a PLT entry for a global symbol. | |
637 | ||
638 | template<bool big_endian> | |
639 | void | |
640 | Target_arm<big_endian>::make_plt_entry(Symbol_table* symtab, Layout* layout, | |
641 | Symbol* gsym) | |
642 | { | |
643 | if (gsym->has_plt_offset()) | |
644 | return; | |
645 | ||
646 | if (this->plt_ == NULL) | |
647 | { | |
648 | // Create the GOT sections first. | |
649 | this->got_section(symtab, layout); | |
650 | ||
651 | this->plt_ = new Output_data_plt_arm<big_endian>(layout, this->got_plt_); | |
652 | layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, | |
653 | (elfcpp::SHF_ALLOC | |
654 | | elfcpp::SHF_EXECINSTR), | |
655 | this->plt_); | |
656 | } | |
657 | this->plt_->add_entry(gsym); | |
658 | } | |
659 | ||
4a657b0d DK |
660 | // Report an unsupported relocation against a local symbol. |
661 | ||
662 | template<bool big_endian> | |
663 | void | |
664 | Target_arm<big_endian>::Scan::unsupported_reloc_local( | |
665 | Sized_relobj<32, big_endian>* object, | |
666 | unsigned int r_type) | |
667 | { | |
668 | gold_error(_("%s: unsupported reloc %u against local symbol"), | |
669 | object->name().c_str(), r_type); | |
670 | } | |
671 | ||
672 | // Scan a relocation for a local symbol. | |
673 | ||
674 | template<bool big_endian> | |
675 | inline void | |
676 | Target_arm<big_endian>::Scan::local(const General_options&, | |
677 | Symbol_table* /* symtab */, | |
678 | Layout* /* layout */, | |
679 | Target_arm* /* target */, | |
680 | Sized_relobj<32, big_endian>* object, | |
681 | unsigned int /* data_shndx */, | |
682 | Output_section* /* output_section */, | |
683 | const elfcpp::Rel<32, big_endian>& /* reloc */, | |
684 | unsigned int r_type, | |
685 | const elfcpp::Sym<32, big_endian>&) | |
686 | { | |
687 | r_type = get_real_reloc_type(r_type); | |
688 | switch (r_type) | |
689 | { | |
690 | case elfcpp::R_ARM_NONE: | |
691 | break; | |
692 | ||
693 | default: | |
694 | unsupported_reloc_local(object, r_type); | |
695 | break; | |
696 | } | |
697 | } | |
698 | ||
699 | // Report an unsupported relocation against a global symbol. | |
700 | ||
701 | template<bool big_endian> | |
702 | void | |
703 | Target_arm<big_endian>::Scan::unsupported_reloc_global( | |
704 | Sized_relobj<32, big_endian>* object, | |
705 | unsigned int r_type, | |
706 | Symbol* gsym) | |
707 | { | |
708 | gold_error(_("%s: unsupported reloc %u against global symbol %s"), | |
709 | object->name().c_str(), r_type, gsym->demangled_name().c_str()); | |
710 | } | |
711 | ||
712 | // Scan a relocation for a global symbol. | |
713 | ||
714 | template<bool big_endian> | |
715 | inline void | |
716 | Target_arm<big_endian>::Scan::global(const General_options&, | |
717 | Symbol_table* /* symtab */, | |
718 | Layout* /* layout */, | |
719 | Target_arm* /* target */, | |
720 | Sized_relobj<32, big_endian>* object, | |
721 | unsigned int /* data_shndx */, | |
722 | Output_section* /* output_section */, | |
723 | const elfcpp::Rel<32, big_endian>& /* reloc */, | |
724 | unsigned int r_type, | |
725 | Symbol* gsym) | |
726 | { | |
727 | r_type = get_real_reloc_type(r_type); | |
728 | switch (r_type) | |
729 | { | |
730 | case elfcpp::R_ARM_NONE: | |
731 | break; | |
732 | ||
733 | default: | |
734 | unsupported_reloc_global(object, r_type, gsym); | |
735 | break; | |
736 | } | |
737 | } | |
738 | ||
739 | // Process relocations for gc. | |
740 | ||
741 | template<bool big_endian> | |
742 | void | |
743 | Target_arm<big_endian>::gc_process_relocs(const General_options& options, | |
744 | Symbol_table* symtab, | |
745 | Layout* layout, | |
746 | Sized_relobj<32, big_endian>* object, | |
747 | unsigned int data_shndx, | |
748 | unsigned int, | |
749 | const unsigned char* prelocs, | |
750 | size_t reloc_count, | |
751 | Output_section* output_section, | |
752 | bool needs_special_offset_handling, | |
753 | size_t local_symbol_count, | |
754 | const unsigned char* plocal_symbols) | |
755 | { | |
756 | typedef Target_arm<big_endian> Arm; | |
757 | typedef typename Target_arm<big_endian>::Scan Scan; | |
758 | ||
759 | gold::gc_process_relocs<32, big_endian, Arm, elfcpp::SHT_REL, Scan>( | |
760 | options, | |
761 | symtab, | |
762 | layout, | |
763 | this, | |
764 | object, | |
765 | data_shndx, | |
766 | prelocs, | |
767 | reloc_count, | |
768 | output_section, | |
769 | needs_special_offset_handling, | |
770 | local_symbol_count, | |
771 | plocal_symbols); | |
772 | } | |
773 | ||
774 | // Scan relocations for a section. | |
775 | ||
776 | template<bool big_endian> | |
777 | void | |
778 | Target_arm<big_endian>::scan_relocs(const General_options& options, | |
779 | Symbol_table* symtab, | |
780 | Layout* layout, | |
781 | Sized_relobj<32, big_endian>* object, | |
782 | unsigned int data_shndx, | |
783 | unsigned int sh_type, | |
784 | const unsigned char* prelocs, | |
785 | size_t reloc_count, | |
786 | Output_section* output_section, | |
787 | bool needs_special_offset_handling, | |
788 | size_t local_symbol_count, | |
789 | const unsigned char* plocal_symbols) | |
790 | { | |
791 | typedef typename Target_arm<big_endian>::Scan Scan; | |
792 | if (sh_type == elfcpp::SHT_RELA) | |
793 | { | |
794 | gold_error(_("%s: unsupported RELA reloc section"), | |
795 | object->name().c_str()); | |
796 | return; | |
797 | } | |
798 | ||
799 | gold::scan_relocs<32, big_endian, Target_arm, elfcpp::SHT_REL, Scan>( | |
800 | options, | |
801 | symtab, | |
802 | layout, | |
803 | this, | |
804 | object, | |
805 | data_shndx, | |
806 | prelocs, | |
807 | reloc_count, | |
808 | output_section, | |
809 | needs_special_offset_handling, | |
810 | local_symbol_count, | |
811 | plocal_symbols); | |
812 | } | |
813 | ||
814 | // Finalize the sections. | |
815 | ||
816 | template<bool big_endian> | |
817 | void | |
94cdfcff | 818 | Target_arm<big_endian>::do_finalize_sections(Layout* layout) |
4a657b0d | 819 | { |
94cdfcff DK |
820 | // Fill in some more dynamic tags. |
821 | Output_data_dynamic* const odyn = layout->dynamic_data(); | |
822 | if (odyn != NULL) | |
823 | { | |
824 | if (this->got_plt_ != NULL) | |
825 | odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); | |
826 | ||
827 | if (this->plt_ != NULL) | |
828 | { | |
829 | const Output_data* od = this->plt_->rel_plt(); | |
830 | odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); | |
831 | odyn->add_section_address(elfcpp::DT_JMPREL, od); | |
832 | odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL); | |
833 | } | |
834 | ||
835 | if (this->rel_dyn_ != NULL) | |
836 | { | |
837 | const Output_data* od = this->rel_dyn_; | |
838 | odyn->add_section_address(elfcpp::DT_REL, od); | |
839 | odyn->add_section_size(elfcpp::DT_RELSZ, od); | |
840 | odyn->add_constant(elfcpp::DT_RELENT, | |
841 | elfcpp::Elf_sizes<32>::rel_size); | |
842 | } | |
843 | ||
844 | if (!parameters->options().shared()) | |
845 | { | |
846 | // The value of the DT_DEBUG tag is filled in by the dynamic | |
847 | // linker at run time, and used by the debugger. | |
848 | odyn->add_constant(elfcpp::DT_DEBUG, 0); | |
849 | } | |
850 | } | |
851 | ||
852 | // Emit any relocs we saved in an attempt to avoid generating COPY | |
853 | // relocs. | |
854 | if (this->copy_relocs_.any_saved_relocs()) | |
855 | this->copy_relocs_.emit(this->rel_dyn_section(layout)); | |
4a657b0d DK |
856 | } |
857 | ||
858 | // Perform a relocation. | |
859 | ||
860 | template<bool big_endian> | |
861 | inline bool | |
862 | Target_arm<big_endian>::Relocate::relocate( | |
863 | const Relocate_info<32, big_endian>* /* relinfo */, | |
864 | Target_arm* /* target */, | |
865 | Output_section* /* output_section */, | |
866 | size_t /* relnum */, | |
867 | const elfcpp::Rel<32, big_endian>& /* rel */, | |
868 | unsigned int r_type, | |
869 | const Sized_symbol<32>* /* gsym */, | |
870 | const Symbol_value<32>* /* psymval */, | |
871 | unsigned char* /* view */, | |
872 | elfcpp::Elf_types<32>::Elf_Addr /* address */, | |
873 | section_size_type /* view_size */ ) | |
874 | { | |
875 | switch (r_type) | |
876 | { | |
877 | case elfcpp::R_ARM_NONE: | |
878 | break; | |
879 | ||
880 | default: | |
881 | gold_unreachable(); | |
882 | } | |
883 | ||
884 | return true; | |
885 | } | |
886 | ||
887 | // Relocate section data. | |
888 | ||
889 | template<bool big_endian> | |
890 | void | |
891 | Target_arm<big_endian>::relocate_section( | |
892 | const Relocate_info<32, big_endian>* relinfo, | |
893 | unsigned int sh_type, | |
894 | const unsigned char* prelocs, | |
895 | size_t reloc_count, | |
896 | Output_section* output_section, | |
897 | bool needs_special_offset_handling, | |
898 | unsigned char* view, | |
899 | elfcpp::Elf_types<32>::Elf_Addr address, | |
900 | section_size_type view_size) | |
901 | { | |
902 | typedef typename Target_arm<big_endian>::Relocate Arm_relocate; | |
903 | gold_assert(sh_type == elfcpp::SHT_REL); | |
904 | ||
905 | gold::relocate_section<32, big_endian, Target_arm, elfcpp::SHT_REL, | |
906 | Arm_relocate>( | |
907 | relinfo, | |
908 | this, | |
909 | prelocs, | |
910 | reloc_count, | |
911 | output_section, | |
912 | needs_special_offset_handling, | |
913 | view, | |
914 | address, | |
915 | view_size); | |
916 | } | |
917 | ||
918 | // Return the size of a relocation while scanning during a relocatable | |
919 | // link. | |
920 | ||
921 | template<bool big_endian> | |
922 | unsigned int | |
923 | Target_arm<big_endian>::Relocatable_size_for_reloc::get_size_for_reloc( | |
924 | unsigned int r_type, | |
925 | Relobj* object) | |
926 | { | |
927 | r_type = get_real_reloc_type(r_type); | |
928 | switch (r_type) | |
929 | { | |
930 | case elfcpp::R_ARM_NONE: | |
931 | return 0; | |
932 | ||
933 | case elfcpp::R_ARM_ABS32: | |
934 | case elfcpp::R_ARM_REL32: | |
935 | case elfcpp::R_ARM_THM_CALL: | |
936 | case elfcpp::R_ARM_GOTOFF32: | |
937 | case elfcpp::R_ARM_BASE_PREL: | |
938 | case elfcpp::R_ARM_GOT_BREL: | |
939 | case elfcpp::R_ARM_PLT32: | |
940 | case elfcpp::R_ARM_CALL: | |
941 | case elfcpp::R_ARM_JUMP24: | |
942 | case elfcpp::R_ARM_PREL31: | |
943 | return 4; | |
944 | ||
945 | case elfcpp::R_ARM_TARGET1: | |
946 | // This should have been mapped to another type already. | |
947 | // Fall through. | |
948 | case elfcpp::R_ARM_COPY: | |
949 | case elfcpp::R_ARM_GLOB_DAT: | |
950 | case elfcpp::R_ARM_JUMP_SLOT: | |
951 | case elfcpp::R_ARM_RELATIVE: | |
952 | // These are relocations which should only be seen by the | |
953 | // dynamic linker, and should never be seen here. | |
954 | gold_error(_("%s: unexpected reloc %u in object file"), | |
955 | object->name().c_str(), r_type); | |
956 | return 0; | |
957 | ||
958 | default: | |
959 | object->error(_("unsupported reloc %u in object file"), r_type); | |
960 | return 0; | |
961 | } | |
962 | } | |
963 | ||
964 | // Scan the relocs during a relocatable link. | |
965 | ||
966 | template<bool big_endian> | |
967 | void | |
968 | Target_arm<big_endian>::scan_relocatable_relocs( | |
969 | const General_options& options, | |
970 | Symbol_table* symtab, | |
971 | Layout* layout, | |
972 | Sized_relobj<32, big_endian>* object, | |
973 | unsigned int data_shndx, | |
974 | unsigned int sh_type, | |
975 | const unsigned char* prelocs, | |
976 | size_t reloc_count, | |
977 | Output_section* output_section, | |
978 | bool needs_special_offset_handling, | |
979 | size_t local_symbol_count, | |
980 | const unsigned char* plocal_symbols, | |
981 | Relocatable_relocs* rr) | |
982 | { | |
983 | gold_assert(sh_type == elfcpp::SHT_REL); | |
984 | ||
985 | typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, | |
986 | Relocatable_size_for_reloc> Scan_relocatable_relocs; | |
987 | ||
988 | gold::scan_relocatable_relocs<32, big_endian, elfcpp::SHT_REL, | |
989 | Scan_relocatable_relocs>( | |
990 | options, | |
991 | symtab, | |
992 | layout, | |
993 | object, | |
994 | data_shndx, | |
995 | prelocs, | |
996 | reloc_count, | |
997 | output_section, | |
998 | needs_special_offset_handling, | |
999 | local_symbol_count, | |
1000 | plocal_symbols, | |
1001 | rr); | |
1002 | } | |
1003 | ||
1004 | // Relocate a section during a relocatable link. | |
1005 | ||
1006 | template<bool big_endian> | |
1007 | void | |
1008 | Target_arm<big_endian>::relocate_for_relocatable( | |
1009 | const Relocate_info<32, big_endian>* relinfo, | |
1010 | unsigned int sh_type, | |
1011 | const unsigned char* prelocs, | |
1012 | size_t reloc_count, | |
1013 | Output_section* output_section, | |
1014 | off_t offset_in_output_section, | |
1015 | const Relocatable_relocs* rr, | |
1016 | unsigned char* view, | |
1017 | elfcpp::Elf_types<32>::Elf_Addr view_address, | |
1018 | section_size_type view_size, | |
1019 | unsigned char* reloc_view, | |
1020 | section_size_type reloc_view_size) | |
1021 | { | |
1022 | gold_assert(sh_type == elfcpp::SHT_REL); | |
1023 | ||
1024 | gold::relocate_for_relocatable<32, big_endian, elfcpp::SHT_REL>( | |
1025 | relinfo, | |
1026 | prelocs, | |
1027 | reloc_count, | |
1028 | output_section, | |
1029 | offset_in_output_section, | |
1030 | rr, | |
1031 | view, | |
1032 | view_address, | |
1033 | view_size, | |
1034 | reloc_view, | |
1035 | reloc_view_size); | |
1036 | } | |
1037 | ||
94cdfcff DK |
1038 | // Return the value to use for a dynamic symbol which requires special |
1039 | // treatment. This is how we support equality comparisons of function | |
1040 | // pointers across shared library boundaries, as described in the | |
1041 | // processor specific ABI supplement. | |
1042 | ||
4a657b0d DK |
1043 | template<bool big_endian> |
1044 | uint64_t | |
94cdfcff | 1045 | Target_arm<big_endian>::do_dynsym_value(const Symbol* gsym) const |
4a657b0d | 1046 | { |
94cdfcff DK |
1047 | gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); |
1048 | return this->plt_section()->address() + gsym->plt_offset(); | |
4a657b0d DK |
1049 | } |
1050 | ||
1051 | // Map platform-specific relocs to real relocs | |
1052 | // | |
1053 | template<bool big_endian> | |
1054 | unsigned int | |
1055 | Target_arm<big_endian>::get_real_reloc_type (unsigned int r_type) | |
1056 | { | |
1057 | switch (r_type) | |
1058 | { | |
1059 | case elfcpp::R_ARM_TARGET1: | |
1060 | // This is either R_ARM_ABS32 or R_ARM_REL32; | |
1061 | return elfcpp::R_ARM_ABS32; | |
1062 | ||
1063 | case elfcpp::R_ARM_TARGET2: | |
1064 | // This can be any reloc type but ususally is R_ARM_GOT_PREL | |
1065 | return elfcpp::R_ARM_GOT_PREL; | |
1066 | ||
1067 | default: | |
1068 | return r_type; | |
1069 | } | |
1070 | } | |
1071 | ||
1072 | // The selector for arm object files. | |
1073 | ||
1074 | template<bool big_endian> | |
1075 | class Target_selector_arm : public Target_selector | |
1076 | { | |
1077 | public: | |
1078 | Target_selector_arm() | |
1079 | : Target_selector(elfcpp::EM_ARM, 32, big_endian, | |
1080 | (big_endian ? "elf32-bigarm" : "elf32-littlearm")) | |
1081 | { } | |
1082 | ||
1083 | Target* | |
1084 | do_instantiate_target() | |
1085 | { return new Target_arm<big_endian>(); } | |
1086 | }; | |
1087 | ||
1088 | Target_selector_arm<false> target_selector_arm; | |
1089 | Target_selector_arm<true> target_selector_armbe; | |
1090 | ||
1091 | } // End anonymous namespace. |