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2e30d253 ILT |
1 | // x86_64.cc -- x86_64 target support for gold. |
2 | ||
3 | // Copyright 2006, 2007, Free Software Foundation, Inc. | |
4 | // Written by Ian Lance Taylor <iant@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or | |
9 | // modify it under the terms of the GNU Library General Public License | |
10 | // as published by the Free Software Foundation; either version 2, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // In addition to the permissions in the GNU Library General Public | |
14 | // License, the Free Software Foundation gives you unlimited | |
15 | // permission to link the compiled version of this file into | |
16 | // combinations with other programs, and to distribute those | |
17 | // combinations without any restriction coming from the use of this | |
18 | // file. (The Library Public License restrictions do apply in other | |
19 | // respects; for example, they cover modification of the file, and | |
20 | /// distribution when not linked into a combined executable.) | |
21 | ||
22 | // This program is distributed in the hope that it will be useful, but | |
23 | // WITHOUT ANY WARRANTY; without even the implied warranty of | |
24 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
25 | // Library General Public License for more details. | |
26 | ||
27 | // You should have received a copy of the GNU Library General Public | |
28 | // License along with this program; if not, write to the Free Software | |
29 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA | |
30 | // 02110-1301, USA. | |
31 | ||
32 | #include "gold.h" | |
33 | ||
34 | #include <cstring> | |
35 | ||
36 | #include "elfcpp.h" | |
37 | #include "parameters.h" | |
38 | #include "reloc.h" | |
39 | #include "x86_64.h" | |
40 | #include "object.h" | |
41 | #include "symtab.h" | |
42 | #include "layout.h" | |
43 | #include "output.h" | |
44 | #include "target.h" | |
45 | #include "target-reloc.h" | |
46 | #include "target-select.h" | |
e041f13d | 47 | #include "tls.h" |
2e30d253 ILT |
48 | |
49 | namespace | |
50 | { | |
51 | ||
52 | using namespace gold; | |
53 | ||
54 | class Output_data_plt_x86_64; | |
55 | ||
56 | // The x86_64 target class. | |
d61c17ea ILT |
57 | // See the ABI at |
58 | // http://www.x86-64.org/documentation/abi.pdf | |
59 | // TLS info comes from | |
60 | // http://people.redhat.com/drepper/tls.pdf | |
0ffd9845 | 61 | // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt |
2e30d253 ILT |
62 | |
63 | class Target_x86_64 : public Sized_target<64, false> | |
64 | { | |
65 | public: | |
e822f2b1 ILT |
66 | // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures |
67 | // uses only Elf64_Rela relocation entries with explicit addends." | |
2e30d253 ILT |
68 | typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section; |
69 | ||
70 | Target_x86_64() | |
71 | : Sized_target<64, false>(&x86_64_info), | |
0ffd9845 | 72 | got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL), |
2e30d253 ILT |
73 | copy_relocs_(NULL), dynbss_(NULL) |
74 | { } | |
75 | ||
76 | // Scan the relocations to look for symbol adjustments. | |
77 | void | |
78 | scan_relocs(const General_options& options, | |
79 | Symbol_table* symtab, | |
80 | Layout* layout, | |
81 | Sized_relobj<64, false>* object, | |
82 | unsigned int data_shndx, | |
83 | unsigned int sh_type, | |
84 | const unsigned char* prelocs, | |
85 | size_t reloc_count, | |
86 | size_t local_symbol_count, | |
87 | const unsigned char* plocal_symbols, | |
88 | Symbol** global_symbols); | |
89 | ||
90 | // Finalize the sections. | |
91 | void | |
92 | do_finalize_sections(Layout*); | |
93 | ||
4fb6c25d ILT |
94 | // Return the value to use for a dynamic which requires special |
95 | // treatment. | |
96 | uint64_t | |
97 | do_dynsym_value(const Symbol*) const; | |
98 | ||
2e30d253 ILT |
99 | // Relocate a section. |
100 | void | |
101 | relocate_section(const Relocate_info<64, false>*, | |
102 | unsigned int sh_type, | |
103 | const unsigned char* prelocs, | |
104 | size_t reloc_count, | |
105 | unsigned char* view, | |
106 | elfcpp::Elf_types<64>::Elf_Addr view_address, | |
107 | off_t view_size); | |
108 | ||
109 | // Return a string used to fill a code section with nops. | |
110 | std::string | |
111 | do_code_fill(off_t length); | |
112 | ||
113 | private: | |
114 | // The class which scans relocations. | |
115 | struct Scan | |
116 | { | |
117 | inline void | |
118 | local(const General_options& options, Symbol_table* symtab, | |
119 | Layout* layout, Target_x86_64* target, | |
120 | Sized_relobj<64, false>* object, | |
121 | unsigned int data_shndx, | |
122 | const elfcpp::Rela<64, false>& reloc, unsigned int r_type, | |
123 | const elfcpp::Sym<64, false>& lsym); | |
124 | ||
125 | inline void | |
126 | global(const General_options& options, Symbol_table* symtab, | |
127 | Layout* layout, Target_x86_64* target, | |
128 | Sized_relobj<64, false>* object, | |
129 | unsigned int data_shndx, | |
130 | const elfcpp::Rela<64, false>& reloc, unsigned int r_type, | |
131 | Symbol* gsym); | |
e041f13d ILT |
132 | |
133 | static void | |
134 | unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type); | |
135 | ||
136 | static void | |
137 | unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type, | |
138 | Symbol*); | |
2e30d253 ILT |
139 | }; |
140 | ||
141 | // The class which implements relocation. | |
142 | class Relocate | |
143 | { | |
144 | public: | |
145 | Relocate() | |
146 | : skip_call_tls_get_addr_(false) | |
147 | { } | |
148 | ||
149 | ~Relocate() | |
150 | { | |
151 | if (this->skip_call_tls_get_addr_) | |
152 | { | |
153 | // FIXME: This needs to specify the location somehow. | |
a0c4fb0a | 154 | gold_error(_("missing expected TLS relocation")); |
2e30d253 ILT |
155 | } |
156 | } | |
157 | ||
158 | // Do a relocation. Return false if the caller should not issue | |
159 | // any warnings about this relocation. | |
160 | inline bool | |
161 | relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum, | |
162 | const elfcpp::Rela<64, false>&, | |
163 | unsigned int r_type, const Sized_symbol<64>*, | |
164 | const Symbol_value<64>*, | |
165 | unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, | |
166 | off_t); | |
167 | ||
168 | private: | |
169 | // Do a TLS relocation. | |
170 | inline void | |
171 | relocate_tls(const Relocate_info<64, false>*, size_t relnum, | |
172 | const elfcpp::Rela<64, false>&, | |
173 | unsigned int r_type, const Sized_symbol<64>*, | |
174 | const Symbol_value<64>*, | |
175 | unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, off_t); | |
176 | ||
177 | // Do a TLS Initial-Exec to Local-Exec transition. | |
178 | static inline void | |
179 | tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum, | |
180 | Output_segment* tls_segment, | |
181 | const elfcpp::Rela<64, false>&, unsigned int r_type, | |
182 | elfcpp::Elf_types<64>::Elf_Addr value, | |
183 | unsigned char* view, | |
184 | off_t view_size); | |
185 | ||
e041f13d | 186 | // Do a TLS General-Dynamic to Local-Exec transition. |
2e30d253 ILT |
187 | inline void |
188 | tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum, | |
189 | Output_segment* tls_segment, | |
190 | const elfcpp::Rela<64, false>&, unsigned int r_type, | |
191 | elfcpp::Elf_types<64>::Elf_Addr value, | |
192 | unsigned char* view, | |
193 | off_t view_size); | |
194 | ||
72ec2876 ILT |
195 | // Do a TLS Local-Dynamic to Local-Exec transition. |
196 | inline void | |
197 | tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum, | |
198 | Output_segment* tls_segment, | |
199 | const elfcpp::Rela<64, false>&, unsigned int r_type, | |
200 | elfcpp::Elf_types<64>::Elf_Addr value, | |
201 | unsigned char* view, | |
202 | off_t view_size); | |
2e30d253 ILT |
203 | |
204 | // This is set if we should skip the next reloc, which should be a | |
205 | // PLT32 reloc against ___tls_get_addr. | |
206 | bool skip_call_tls_get_addr_; | |
207 | }; | |
208 | ||
209 | // Adjust TLS relocation type based on the options and whether this | |
210 | // is a local symbol. | |
e041f13d | 211 | static tls::Tls_optimization |
2e30d253 ILT |
212 | optimize_tls_reloc(bool is_final, int r_type); |
213 | ||
214 | // Get the GOT section, creating it if necessary. | |
215 | Output_data_got<64, false>* | |
216 | got_section(Symbol_table*, Layout*); | |
217 | ||
218 | // Create a PLT entry for a global symbol. | |
219 | void | |
220 | make_plt_entry(Symbol_table*, Layout*, Symbol*); | |
221 | ||
222 | // Get the PLT section. | |
223 | Output_data_plt_x86_64* | |
224 | plt_section() const | |
225 | { | |
226 | gold_assert(this->plt_ != NULL); | |
227 | return this->plt_; | |
228 | } | |
229 | ||
230 | // Get the dynamic reloc section, creating it if necessary. | |
231 | Reloc_section* | |
0ffd9845 | 232 | rela_dyn_section(Layout*); |
2e30d253 ILT |
233 | |
234 | // Copy a relocation against a global symbol. | |
235 | void | |
236 | copy_reloc(const General_options*, Symbol_table*, Layout*, | |
237 | Sized_relobj<64, false>*, unsigned int, | |
238 | Symbol*, const elfcpp::Rela<64, false>&); | |
239 | ||
240 | // Information about this specific target which we pass to the | |
241 | // general Target structure. | |
242 | static const Target::Target_info x86_64_info; | |
243 | ||
244 | // The GOT section. | |
245 | Output_data_got<64, false>* got_; | |
246 | // The PLT section. | |
247 | Output_data_plt_x86_64* plt_; | |
248 | // The GOT PLT section. | |
249 | Output_data_space* got_plt_; | |
250 | // The dynamic reloc section. | |
0ffd9845 | 251 | Reloc_section* rela_dyn_; |
2e30d253 ILT |
252 | // Relocs saved to avoid a COPY reloc. |
253 | Copy_relocs<64, false>* copy_relocs_; | |
254 | // Space for variables copied with a COPY reloc. | |
255 | Output_data_space* dynbss_; | |
256 | }; | |
257 | ||
258 | const Target::Target_info Target_x86_64::x86_64_info = | |
259 | { | |
260 | 64, // size | |
261 | false, // is_big_endian | |
262 | elfcpp::EM_X86_64, // machine_code | |
263 | false, // has_make_symbol | |
264 | false, // has_resolve | |
265 | true, // has_code_fill | |
266 | "/lib/ld64.so.1", // program interpreter | |
267 | 0x400000, // text_segment_address | |
268 | 0x1000, // abi_pagesize | |
269 | 0x1000 // common_pagesize | |
270 | }; | |
271 | ||
272 | // Get the GOT section, creating it if necessary. | |
273 | ||
274 | Output_data_got<64, false>* | |
275 | Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) | |
276 | { | |
277 | if (this->got_ == NULL) | |
278 | { | |
279 | gold_assert(symtab != NULL && layout != NULL); | |
280 | ||
281 | this->got_ = new Output_data_got<64, false>(); | |
282 | ||
283 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, | |
284 | elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, | |
285 | this->got_); | |
286 | ||
287 | // The old GNU linker creates a .got.plt section. We just | |
288 | // create another set of data in the .got section. Note that we | |
289 | // always create a PLT if we create a GOT, although the PLT | |
290 | // might be empty. | |
291 | // TODO(csilvers): do we really need an alignment of 8? | |
292 | this->got_plt_ = new Output_data_space(8); | |
293 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, | |
294 | elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, | |
295 | this->got_plt_); | |
296 | ||
297 | // The first three entries are reserved. | |
298 | this->got_plt_->set_space_size(3 * 8); | |
299 | ||
300 | // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. | |
301 | symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL, | |
302 | this->got_plt_, | |
303 | 0, 0, elfcpp::STT_OBJECT, | |
304 | elfcpp::STB_LOCAL, | |
305 | elfcpp::STV_HIDDEN, 0, | |
306 | false, false); | |
307 | } | |
308 | ||
309 | return this->got_; | |
310 | } | |
311 | ||
312 | // Get the dynamic reloc section, creating it if necessary. | |
313 | ||
314 | Target_x86_64::Reloc_section* | |
0ffd9845 | 315 | Target_x86_64::rela_dyn_section(Layout* layout) |
2e30d253 | 316 | { |
0ffd9845 | 317 | if (this->rela_dyn_ == NULL) |
2e30d253 ILT |
318 | { |
319 | gold_assert(layout != NULL); | |
0ffd9845 | 320 | this->rela_dyn_ = new Reloc_section(); |
2e30d253 | 321 | layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, |
0ffd9845 | 322 | elfcpp::SHF_ALLOC, this->rela_dyn_); |
2e30d253 | 323 | } |
0ffd9845 | 324 | return this->rela_dyn_; |
2e30d253 ILT |
325 | } |
326 | ||
327 | // A class to handle the PLT data. | |
328 | ||
329 | class Output_data_plt_x86_64 : public Output_section_data | |
330 | { | |
331 | public: | |
332 | typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section; | |
333 | ||
334 | Output_data_plt_x86_64(Layout*, Output_data_space*); | |
335 | ||
336 | // Add an entry to the PLT. | |
337 | void | |
338 | add_entry(Symbol* gsym); | |
339 | ||
340 | // Return the .rel.plt section data. | |
341 | const Reloc_section* | |
342 | rel_plt() const | |
343 | { return this->rel_; } | |
344 | ||
345 | protected: | |
346 | void | |
347 | do_adjust_output_section(Output_section* os); | |
348 | ||
349 | private: | |
350 | // The size of an entry in the PLT. | |
351 | static const int plt_entry_size = 16; | |
352 | ||
353 | // The first entry in the PLT. | |
354 | // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same | |
355 | // procedure linkage table for both programs and shared objects." | |
356 | static unsigned char first_plt_entry[plt_entry_size]; | |
357 | ||
358 | // Other entries in the PLT for an executable. | |
359 | static unsigned char plt_entry[plt_entry_size]; | |
360 | ||
361 | // Set the final size. | |
362 | void | |
363 | do_set_address(uint64_t, off_t) | |
364 | { this->set_data_size((this->count_ + 1) * plt_entry_size); } | |
365 | ||
366 | // Write out the PLT data. | |
367 | void | |
368 | do_write(Output_file*); | |
369 | ||
370 | // The reloc section. | |
371 | Reloc_section* rel_; | |
372 | // The .got.plt section. | |
373 | Output_data_space* got_plt_; | |
374 | // The number of PLT entries. | |
375 | unsigned int count_; | |
376 | }; | |
377 | ||
378 | // Create the PLT section. The ordinary .got section is an argument, | |
379 | // since we need to refer to the start. We also create our own .got | |
380 | // section just for PLT entries. | |
381 | ||
382 | Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout, | |
383 | Output_data_space* got_plt) | |
384 | // TODO(csilvers): do we really need an alignment of 8? | |
385 | : Output_section_data(8), got_plt_(got_plt), count_(0) | |
386 | { | |
387 | this->rel_ = new Reloc_section(); | |
388 | layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, | |
389 | elfcpp::SHF_ALLOC, this->rel_); | |
390 | } | |
391 | ||
392 | void | |
393 | Output_data_plt_x86_64::do_adjust_output_section(Output_section* os) | |
394 | { | |
395 | // UnixWare sets the entsize of .plt to 4, and so does the old GNU | |
396 | // linker, and so do we. | |
397 | os->set_entsize(4); | |
398 | } | |
399 | ||
400 | // Add an entry to the PLT. | |
401 | ||
402 | void | |
403 | Output_data_plt_x86_64::add_entry(Symbol* gsym) | |
404 | { | |
405 | gold_assert(!gsym->has_plt_offset()); | |
406 | ||
407 | // Note that when setting the PLT offset we skip the initial | |
408 | // reserved PLT entry. | |
409 | gsym->set_plt_offset((this->count_ + 1) * plt_entry_size); | |
410 | ||
411 | ++this->count_; | |
412 | ||
413 | off_t got_offset = this->got_plt_->data_size(); | |
414 | ||
415 | // Every PLT entry needs a GOT entry which points back to the PLT | |
416 | // entry (this will be changed by the dynamic linker, normally | |
417 | // lazily when the function is called). | |
418 | this->got_plt_->set_space_size(got_offset + 8); | |
419 | ||
420 | // Every PLT entry needs a reloc. | |
421 | gsym->set_needs_dynsym_entry(); | |
422 | this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, | |
423 | got_offset, 0); | |
424 | ||
425 | // Note that we don't need to save the symbol. The contents of the | |
426 | // PLT are independent of which symbols are used. The symbols only | |
427 | // appear in the relocations. | |
428 | } | |
429 | ||
430 | // The first entry in the PLT for an executable. | |
431 | ||
432 | unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] = | |
433 | { | |
434 | // From AMD64 ABI Draft 0.98, page 76 | |
435 | 0xff, 0x35, // pushq contents of memory address | |
436 | 0, 0, 0, 0, // replaced with address of .got + 4 | |
437 | 0xff, 0x25, // jmp indirect | |
438 | 0, 0, 0, 0, // replaced with address of .got + 8 | |
439 | 0x90, 0x90, 0x90, 0x90 // noop (x4) | |
440 | }; | |
441 | ||
442 | // Subsequent entries in the PLT for an executable. | |
443 | ||
444 | unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] = | |
445 | { | |
446 | // From AMD64 ABI Draft 0.98, page 76 | |
447 | 0xff, 0x25, // jmpq indirect | |
448 | 0, 0, 0, 0, // replaced with address of symbol in .got | |
449 | 0x68, // pushq immediate | |
450 | 0, 0, 0, 0, // replaced with offset into relocation table | |
451 | 0xe9, // jmpq relative | |
452 | 0, 0, 0, 0 // replaced with offset to start of .plt | |
453 | }; | |
454 | ||
455 | // Write out the PLT. This uses the hand-coded instructions above, | |
456 | // and adjusts them as needed. This is specified by the AMD64 ABI. | |
457 | ||
458 | void | |
459 | Output_data_plt_x86_64::do_write(Output_file* of) | |
460 | { | |
461 | const off_t offset = this->offset(); | |
462 | const off_t oview_size = this->data_size(); | |
463 | unsigned char* const oview = of->get_output_view(offset, oview_size); | |
464 | ||
465 | const off_t got_file_offset = this->got_plt_->offset(); | |
466 | const off_t got_size = this->got_plt_->data_size(); | |
467 | unsigned char* const got_view = of->get_output_view(got_file_offset, | |
468 | got_size); | |
469 | ||
470 | unsigned char* pov = oview; | |
471 | ||
472 | elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); | |
473 | elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); | |
474 | ||
475 | memcpy(pov, first_plt_entry, plt_entry_size); | |
476 | if (!parameters->output_is_shared()) | |
477 | { | |
478 | // We do a jmp relative to the PC at the end of this instruction. | |
479 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8 | |
480 | - (plt_address + 6)); | |
481 | elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16 | |
482 | - (plt_address + 12)); | |
483 | } | |
484 | pov += plt_entry_size; | |
485 | ||
486 | unsigned char* got_pov = got_view; | |
487 | ||
488 | memset(got_pov, 0, 24); | |
489 | got_pov += 24; | |
490 | ||
491 | unsigned int plt_offset = plt_entry_size; | |
492 | unsigned int got_offset = 24; | |
493 | const unsigned int count = this->count_; | |
494 | for (unsigned int plt_index = 0; | |
495 | plt_index < count; | |
496 | ++plt_index, | |
497 | pov += plt_entry_size, | |
498 | got_pov += 8, | |
499 | plt_offset += plt_entry_size, | |
500 | got_offset += 8) | |
501 | { | |
502 | // Set and adjust the PLT entry itself. | |
503 | memcpy(pov, plt_entry, plt_entry_size); | |
504 | if (parameters->output_is_shared()) | |
505 | // FIXME(csilvers): what's the right thing to write here? | |
506 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); | |
507 | else | |
508 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, | |
509 | (got_address + got_offset | |
510 | - (plt_address + plt_offset | |
511 | + 6))); | |
512 | ||
513 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index); | |
514 | elfcpp::Swap<32, false>::writeval(pov + 12, | |
515 | - (plt_offset + plt_entry_size)); | |
516 | ||
517 | // Set the entry in the GOT. | |
518 | elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6); | |
519 | } | |
520 | ||
521 | gold_assert(pov - oview == oview_size); | |
522 | gold_assert(got_pov - got_view == got_size); | |
523 | ||
524 | of->write_output_view(offset, oview_size, oview); | |
525 | of->write_output_view(got_file_offset, got_size, got_view); | |
526 | } | |
527 | ||
528 | // Create a PLT entry for a global symbol. | |
529 | ||
530 | void | |
531 | Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, | |
532 | Symbol* gsym) | |
533 | { | |
534 | if (gsym->has_plt_offset()) | |
535 | return; | |
536 | ||
537 | if (this->plt_ == NULL) | |
538 | { | |
539 | // Create the GOT sections first. | |
540 | this->got_section(symtab, layout); | |
541 | ||
542 | this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_); | |
543 | layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, | |
544 | (elfcpp::SHF_ALLOC | |
545 | | elfcpp::SHF_EXECINSTR), | |
546 | this->plt_); | |
547 | } | |
548 | ||
549 | this->plt_->add_entry(gsym); | |
550 | } | |
551 | ||
552 | // Handle a relocation against a non-function symbol defined in a | |
553 | // dynamic object. The traditional way to handle this is to generate | |
554 | // a COPY relocation to copy the variable at runtime from the shared | |
555 | // object into the executable's data segment. However, this is | |
556 | // undesirable in general, as if the size of the object changes in the | |
557 | // dynamic object, the executable will no longer work correctly. If | |
558 | // this relocation is in a writable section, then we can create a | |
559 | // dynamic reloc and the dynamic linker will resolve it to the correct | |
560 | // address at runtime. However, we do not want do that if the | |
561 | // relocation is in a read-only section, as it would prevent the | |
562 | // readonly segment from being shared. And if we have to eventually | |
563 | // generate a COPY reloc, then any dynamic relocations will be | |
564 | // useless. So this means that if this is a writable section, we need | |
565 | // to save the relocation until we see whether we have to create a | |
566 | // COPY relocation for this symbol for any other relocation. | |
567 | ||
568 | void | |
569 | Target_x86_64::copy_reloc(const General_options* options, | |
d61c17ea ILT |
570 | Symbol_table* symtab, |
571 | Layout* layout, | |
572 | Sized_relobj<64, false>* object, | |
573 | unsigned int data_shndx, Symbol* gsym, | |
72ec2876 | 574 | const elfcpp::Rela<64, false>& rela) |
2e30d253 ILT |
575 | { |
576 | Sized_symbol<64>* ssym; | |
577 | ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(64) (gsym | |
578 | SELECT_SIZE(64)); | |
579 | ||
580 | if (!Copy_relocs<64, false>::need_copy_reloc(options, object, | |
581 | data_shndx, ssym)) | |
582 | { | |
583 | // So far we do not need a COPY reloc. Save this relocation. | |
584 | // If it turns out that we never need a COPY reloc for this | |
585 | // symbol, then we will emit the relocation. | |
586 | if (this->copy_relocs_ == NULL) | |
587 | this->copy_relocs_ = new Copy_relocs<64, false>(); | |
72ec2876 | 588 | this->copy_relocs_->save(ssym, object, data_shndx, rela); |
2e30d253 ILT |
589 | } |
590 | else | |
591 | { | |
592 | // Allocate space for this symbol in the .bss section. | |
593 | ||
594 | elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize(); | |
595 | ||
596 | // There is no defined way to determine the required alignment | |
597 | // of the symbol. We pick the alignment based on the size. We | |
598 | // set an arbitrary maximum of 256. | |
599 | unsigned int align; | |
600 | for (align = 1; align < 512; align <<= 1) | |
601 | if ((symsize & align) != 0) | |
602 | break; | |
603 | ||
604 | if (this->dynbss_ == NULL) | |
605 | { | |
606 | this->dynbss_ = new Output_data_space(align); | |
607 | layout->add_output_section_data(".bss", | |
608 | elfcpp::SHT_NOBITS, | |
609 | (elfcpp::SHF_ALLOC | |
610 | | elfcpp::SHF_WRITE), | |
611 | this->dynbss_); | |
612 | } | |
613 | ||
614 | Output_data_space* dynbss = this->dynbss_; | |
615 | ||
616 | if (align > dynbss->addralign()) | |
617 | dynbss->set_space_alignment(align); | |
618 | ||
619 | off_t dynbss_size = dynbss->data_size(); | |
620 | dynbss_size = align_address(dynbss_size, align); | |
621 | off_t offset = dynbss_size; | |
622 | dynbss->set_space_size(dynbss_size + symsize); | |
623 | ||
624 | // Define the symbol in the .dynbss section. | |
625 | symtab->define_in_output_data(this, ssym->name(), ssym->version(), | |
626 | dynbss, offset, symsize, ssym->type(), | |
627 | ssym->binding(), ssym->visibility(), | |
628 | ssym->nonvis(), false, false); | |
629 | ||
630 | // Add the COPY reloc. | |
631 | ssym->set_needs_dynsym_entry(); | |
0ffd9845 ILT |
632 | Reloc_section* rela_dyn = this->rela_dyn_section(layout); |
633 | rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0); | |
2e30d253 ILT |
634 | } |
635 | } | |
636 | ||
637 | ||
638 | // Optimize the TLS relocation type based on what we know about the | |
639 | // symbol. IS_FINAL is true if the final address of this symbol is | |
640 | // known at link time. | |
641 | ||
e041f13d | 642 | tls::Tls_optimization |
2e30d253 ILT |
643 | Target_x86_64::optimize_tls_reloc(bool is_final, int r_type) |
644 | { | |
2e30d253 ILT |
645 | // If we are generating a shared library, then we can't do anything |
646 | // in the linker. | |
647 | if (parameters->output_is_shared()) | |
e041f13d | 648 | return tls::TLSOPT_NONE; |
2e30d253 ILT |
649 | |
650 | switch (r_type) | |
651 | { | |
652 | case elfcpp::R_X86_64_TLSGD: | |
e041f13d ILT |
653 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: |
654 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
655 | // These are General-Dynamic which permits fully general TLS | |
2e30d253 ILT |
656 | // access. Since we know that we are generating an executable, |
657 | // we can convert this to Initial-Exec. If we also know that | |
658 | // this is a local symbol, we can further switch to Local-Exec. | |
659 | if (is_final) | |
e041f13d ILT |
660 | return tls::TLSOPT_TO_LE; |
661 | return tls::TLSOPT_TO_IE; | |
2e30d253 | 662 | |
d61c17ea | 663 | case elfcpp::R_X86_64_TLSLD: |
2e30d253 ILT |
664 | // This is Local-Dynamic, which refers to a local symbol in the |
665 | // dynamic TLS block. Since we know that we generating an | |
666 | // executable, we can switch to Local-Exec. | |
e041f13d | 667 | return tls::TLSOPT_TO_LE; |
2e30d253 | 668 | |
0ffd9845 | 669 | case elfcpp::R_X86_64_DTPOFF32: |
0ffd9845 ILT |
670 | case elfcpp::R_X86_64_DTPOFF64: |
671 | // Another Local-Dynamic reloc. | |
e041f13d | 672 | return tls::TLSOPT_TO_LE; |
0ffd9845 | 673 | |
d61c17ea | 674 | case elfcpp::R_X86_64_GOTTPOFF: |
2e30d253 ILT |
675 | // These are Initial-Exec relocs which get the thread offset |
676 | // from the GOT. If we know that we are linking against the | |
677 | // local symbol, we can switch to Local-Exec, which links the | |
678 | // thread offset into the instruction. | |
679 | if (is_final) | |
e041f13d ILT |
680 | return tls::TLSOPT_TO_LE; |
681 | return tls::TLSOPT_NONE; | |
2e30d253 | 682 | |
d61c17ea | 683 | case elfcpp::R_X86_64_TPOFF32: |
2e30d253 ILT |
684 | // When we already have Local-Exec, there is nothing further we |
685 | // can do. | |
e041f13d | 686 | return tls::TLSOPT_NONE; |
2e30d253 ILT |
687 | |
688 | default: | |
689 | gold_unreachable(); | |
690 | } | |
2e30d253 ILT |
691 | } |
692 | ||
e041f13d ILT |
693 | // Report an unsupported relocation against a local symbol. |
694 | ||
695 | void | |
696 | Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object, | |
697 | unsigned int r_type) | |
698 | { | |
75f2446e ILT |
699 | gold_error(_("%s: unsupported reloc %u against local symbol"), |
700 | object->name().c_str(), r_type); | |
e041f13d ILT |
701 | } |
702 | ||
2e30d253 ILT |
703 | // Scan a relocation for a local symbol. |
704 | ||
705 | inline void | |
706 | Target_x86_64::Scan::local(const General_options&, | |
d61c17ea ILT |
707 | Symbol_table* symtab, |
708 | Layout* layout, | |
709 | Target_x86_64* target, | |
710 | Sized_relobj<64, false>* object, | |
0ffd9845 ILT |
711 | unsigned int data_shndx, |
712 | const elfcpp::Rela<64, false>& reloc, | |
d61c17ea ILT |
713 | unsigned int r_type, |
714 | const elfcpp::Sym<64, false>&) | |
2e30d253 ILT |
715 | { |
716 | switch (r_type) | |
717 | { | |
718 | case elfcpp::R_X86_64_NONE: | |
e822f2b1 ILT |
719 | case elfcpp::R_386_GNU_VTINHERIT: |
720 | case elfcpp::R_386_GNU_VTENTRY: | |
2e30d253 ILT |
721 | break; |
722 | ||
723 | case elfcpp::R_X86_64_64: | |
724 | case elfcpp::R_X86_64_32: | |
725 | case elfcpp::R_X86_64_32S: | |
726 | case elfcpp::R_X86_64_16: | |
727 | case elfcpp::R_X86_64_8: | |
728 | // FIXME: If we are generating a shared object we need to copy | |
729 | // this relocation into the object. | |
730 | gold_assert(!parameters->output_is_shared()); | |
731 | break; | |
732 | ||
733 | case elfcpp::R_X86_64_PC64: | |
734 | case elfcpp::R_X86_64_PC32: | |
735 | case elfcpp::R_X86_64_PC16: | |
736 | case elfcpp::R_X86_64_PC8: | |
737 | break; | |
738 | ||
e822f2b1 | 739 | case elfcpp::R_X86_64_GOTPC32: // TODO(csilvers): correct? |
e822f2b1 ILT |
740 | case elfcpp::R_X86_64_GOTOFF64: |
741 | case elfcpp::R_X86_64_GOTPC64: // TODO(csilvers): correct? | |
e822f2b1 | 742 | case elfcpp::R_X86_64_PLTOFF64: // TODO(csilvers): correct? |
2e30d253 ILT |
743 | // We need a GOT section. |
744 | target->got_section(symtab, layout); | |
745 | break; | |
746 | ||
0ffd9845 ILT |
747 | case elfcpp::R_X86_64_GOT64: |
748 | case elfcpp::R_X86_64_GOT32: | |
749 | case elfcpp::R_X86_64_GOTPCREL64: | |
750 | case elfcpp::R_X86_64_GOTPCREL: | |
751 | { | |
752 | // The symbol requires a GOT entry. | |
753 | Output_data_got<64, false>* got = target->got_section(symtab, layout); | |
754 | unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); | |
755 | if (got->add_local(object, r_sym)) | |
756 | { | |
757 | // If we are generating a shared object, we need to add a | |
758 | // dynamic RELATIVE relocation for this symbol. | |
759 | if (parameters->output_is_shared()) | |
760 | { | |
761 | Reloc_section* rela_dyn = target->rela_dyn_section(layout); | |
762 | rela_dyn->add_local(object, 0, elfcpp::R_X86_64_RELATIVE, | |
763 | data_shndx, reloc.get_r_offset(), 0); | |
764 | } | |
765 | } | |
766 | } | |
767 | break; | |
768 | ||
2e30d253 ILT |
769 | case elfcpp::R_X86_64_COPY: |
770 | case elfcpp::R_X86_64_GLOB_DAT: | |
771 | case elfcpp::R_X86_64_JUMP_SLOT: | |
772 | case elfcpp::R_X86_64_RELATIVE: | |
d61c17ea | 773 | // These are outstanding tls relocs, which are unexpected when linking |
2e30d253 | 774 | case elfcpp::R_X86_64_TPOFF64: |
2e30d253 | 775 | case elfcpp::R_X86_64_DTPMOD64: |
2e30d253 | 776 | case elfcpp::R_X86_64_TLSDESC: |
75f2446e ILT |
777 | gold_error(_("%s: unexpected reloc %u in object file"), |
778 | object->name().c_str(), r_type); | |
2e30d253 ILT |
779 | break; |
780 | ||
d61c17ea | 781 | // These are initial tls relocs, which are expected when linking |
e041f13d ILT |
782 | case elfcpp::R_X86_64_TLSGD: |
783 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: | |
784 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
785 | case elfcpp::R_X86_64_TLSLD: | |
786 | case elfcpp::R_X86_64_GOTTPOFF: | |
787 | case elfcpp::R_X86_64_TPOFF32: | |
0ffd9845 ILT |
788 | case elfcpp::R_X86_64_DTPOFF32: |
789 | case elfcpp::R_X86_64_DTPOFF64: | |
2e30d253 ILT |
790 | { |
791 | bool output_is_shared = parameters->output_is_shared(); | |
e041f13d ILT |
792 | const tls::Tls_optimization optimized_type |
793 | = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type); | |
2e30d253 ILT |
794 | switch (r_type) |
795 | { | |
d61c17ea | 796 | case elfcpp::R_X86_64_TPOFF32: // Local-exec |
2e30d253 ILT |
797 | // FIXME: If generating a shared object, we need to copy |
798 | // this relocation into the object. | |
799 | gold_assert(!output_is_shared); | |
800 | break; | |
801 | ||
e041f13d ILT |
802 | case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec |
803 | // FIXME: If not relaxing to LE, we need to generate a | |
804 | // TPOFF64 reloc. | |
805 | if (optimized_type != tls::TLSOPT_TO_LE) | |
806 | unsupported_reloc_local(object, r_type); | |
807 | break; | |
808 | ||
809 | case elfcpp::R_X86_64_TLSLD: // Local-dynamic | |
0ffd9845 ILT |
810 | case elfcpp::R_X86_64_DTPOFF32: |
811 | case elfcpp::R_X86_64_DTPOFF64: | |
e041f13d ILT |
812 | // FIXME: If not relaxing to LE, we need to generate a |
813 | // DTPMOD64 reloc. | |
814 | if (optimized_type != tls::TLSOPT_TO_LE) | |
815 | unsupported_reloc_local(object, r_type); | |
816 | break; | |
817 | ||
0ffd9845 | 818 | |
e041f13d | 819 | case elfcpp::R_X86_64_TLSGD: // General-dynamic |
d61c17ea ILT |
820 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: |
821 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
e041f13d ILT |
822 | // FIXME: If not relaxing to LE, we need to generate |
823 | // DTPMOD64 and DTPOFF64 relocs. | |
824 | if (optimized_type != tls::TLSOPT_TO_LE) | |
825 | unsupported_reloc_local(object, r_type); | |
2e30d253 | 826 | break; |
e041f13d ILT |
827 | |
828 | default: | |
829 | gold_unreachable(); | |
2e30d253 ILT |
830 | } |
831 | } | |
832 | break; | |
2e30d253 | 833 | |
0ffd9845 | 834 | case elfcpp::R_X86_64_GOTPLT64: |
2e30d253 | 835 | case elfcpp::R_X86_64_PLT32: |
e822f2b1 ILT |
836 | case elfcpp::R_X86_64_SIZE32: // TODO(csilvers): correct? |
837 | case elfcpp::R_X86_64_SIZE64: // TODO(csilvers): correct? | |
2e30d253 | 838 | default: |
75f2446e ILT |
839 | gold_error(_("%s: unsupported reloc %u against local symbol"), |
840 | object->name().c_str(), r_type); | |
2e30d253 ILT |
841 | break; |
842 | } | |
843 | } | |
844 | ||
845 | ||
e041f13d ILT |
846 | // Report an unsupported relocation against a global symbol. |
847 | ||
848 | void | |
849 | Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object, | |
850 | unsigned int r_type, | |
851 | Symbol* gsym) | |
852 | { | |
75f2446e ILT |
853 | gold_error(_("%s: unsupported reloc %u against global symbol %s"), |
854 | object->name().c_str(), r_type, gsym->name()); | |
e041f13d ILT |
855 | } |
856 | ||
2e30d253 ILT |
857 | // Scan a relocation for a global symbol. |
858 | ||
859 | inline void | |
860 | Target_x86_64::Scan::global(const General_options& options, | |
d61c17ea ILT |
861 | Symbol_table* symtab, |
862 | Layout* layout, | |
863 | Target_x86_64* target, | |
864 | Sized_relobj<64, false>* object, | |
865 | unsigned int data_shndx, | |
866 | const elfcpp::Rela<64, false>& reloc, | |
867 | unsigned int r_type, | |
868 | Symbol* gsym) | |
2e30d253 ILT |
869 | { |
870 | switch (r_type) | |
871 | { | |
872 | case elfcpp::R_X86_64_NONE: | |
e822f2b1 ILT |
873 | case elfcpp::R_386_GNU_VTINHERIT: |
874 | case elfcpp::R_386_GNU_VTENTRY: | |
2e30d253 ILT |
875 | break; |
876 | ||
877 | case elfcpp::R_X86_64_64: | |
878 | case elfcpp::R_X86_64_PC64: | |
879 | case elfcpp::R_X86_64_32: | |
880 | case elfcpp::R_X86_64_32S: | |
881 | case elfcpp::R_X86_64_PC32: | |
882 | case elfcpp::R_X86_64_16: | |
883 | case elfcpp::R_X86_64_PC16: | |
884 | case elfcpp::R_X86_64_8: | |
885 | case elfcpp::R_X86_64_PC8: | |
886 | // FIXME: If we are generating a shared object we may need to | |
887 | // copy this relocation into the object. If this symbol is | |
888 | // defined in a shared object, we may need to copy this | |
889 | // relocation in order to avoid a COPY relocation. | |
890 | gold_assert(!parameters->output_is_shared()); | |
891 | ||
892 | if (gsym->is_from_dynobj()) | |
893 | { | |
894 | // This symbol is defined in a dynamic object. If it is a | |
895 | // function, we make a PLT entry. Otherwise we need to | |
896 | // either generate a COPY reloc or copy this reloc. | |
897 | if (gsym->type() == elfcpp::STT_FUNC) | |
4fb6c25d ILT |
898 | { |
899 | target->make_plt_entry(symtab, layout, gsym); | |
900 | ||
901 | // If this is not a PC relative reference, then we may | |
902 | // be taking the address of the function. In that case | |
903 | // we need to set the entry in the dynamic symbol table | |
904 | // to the address of the PLT entry. | |
905 | if (r_type != elfcpp::R_X86_64_PC64 | |
906 | && r_type != elfcpp::R_X86_64_PC32 | |
907 | && r_type != elfcpp::R_X86_64_PC16 | |
908 | && r_type != elfcpp::R_X86_64_PC8) | |
909 | gsym->set_needs_dynsym_value(); | |
910 | } | |
2e30d253 ILT |
911 | else |
912 | target->copy_reloc(&options, symtab, layout, object, data_shndx, | |
913 | gsym, reloc); | |
914 | } | |
915 | ||
916 | break; | |
917 | ||
ff006520 | 918 | case elfcpp::R_X86_64_GOT64: |
2e30d253 | 919 | case elfcpp::R_X86_64_GOT32: |
ff006520 ILT |
920 | case elfcpp::R_X86_64_GOTPCREL64: |
921 | case elfcpp::R_X86_64_GOTPCREL: | |
922 | case elfcpp::R_X86_64_GOTPLT64: | |
2e30d253 ILT |
923 | { |
924 | // The symbol requires a GOT entry. | |
925 | Output_data_got<64, false>* got = target->got_section(symtab, layout); | |
926 | if (got->add_global(gsym)) | |
927 | { | |
928 | // If this symbol is not fully resolved, we need to add a | |
929 | // dynamic relocation for it. | |
930 | if (!gsym->final_value_is_known()) | |
931 | { | |
0ffd9845 ILT |
932 | Reloc_section* rela_dyn = target->rela_dyn_section(layout); |
933 | rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT, got, | |
934 | gsym->got_offset(), 0); | |
2e30d253 ILT |
935 | } |
936 | } | |
937 | } | |
938 | break; | |
939 | ||
940 | case elfcpp::R_X86_64_PLT32: | |
941 | // If the symbol is fully resolved, this is just a PC32 reloc. | |
942 | // Otherwise we need a PLT entry. | |
943 | if (gsym->final_value_is_known()) | |
944 | break; | |
945 | target->make_plt_entry(symtab, layout, gsym); | |
946 | break; | |
947 | ||
e822f2b1 | 948 | case elfcpp::R_X86_64_GOTPC32: // TODO(csilvers): correct? |
e822f2b1 ILT |
949 | case elfcpp::R_X86_64_GOTOFF64: |
950 | case elfcpp::R_X86_64_GOTPC64: // TODO(csilvers): correct? | |
e822f2b1 | 951 | case elfcpp::R_X86_64_PLTOFF64: // TODO(csilvers): correct? |
2e30d253 ILT |
952 | // We need a GOT section. |
953 | target->got_section(symtab, layout); | |
954 | break; | |
955 | ||
2e30d253 ILT |
956 | case elfcpp::R_X86_64_COPY: |
957 | case elfcpp::R_X86_64_GLOB_DAT: | |
958 | case elfcpp::R_X86_64_JUMP_SLOT: | |
959 | case elfcpp::R_X86_64_RELATIVE: | |
d61c17ea | 960 | // These are outstanding tls relocs, which are unexpected when linking |
e822f2b1 | 961 | case elfcpp::R_X86_64_TPOFF64: |
2e30d253 | 962 | case elfcpp::R_X86_64_DTPMOD64: |
e822f2b1 | 963 | case elfcpp::R_X86_64_TLSDESC: |
75f2446e ILT |
964 | gold_error(_("%s: unexpected reloc %u in object file"), |
965 | object->name().c_str(), r_type); | |
2e30d253 | 966 | break; |
2e30d253 | 967 | |
d61c17ea | 968 | // These are initial tls relocs, which are expected for global() |
e041f13d ILT |
969 | case elfcpp::R_X86_64_TLSGD: |
970 | case elfcpp::R_X86_64_TLSLD: | |
971 | case elfcpp::R_X86_64_GOTTPOFF: | |
972 | case elfcpp::R_X86_64_TPOFF32: | |
973 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: | |
974 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
0ffd9845 ILT |
975 | case elfcpp::R_X86_64_DTPOFF32: |
976 | case elfcpp::R_X86_64_DTPOFF64: | |
2e30d253 ILT |
977 | { |
978 | const bool is_final = gsym->final_value_is_known(); | |
e041f13d ILT |
979 | const tls::Tls_optimization optimized_type |
980 | = Target_x86_64::optimize_tls_reloc(is_final, r_type); | |
2e30d253 ILT |
981 | switch (r_type) |
982 | { | |
d61c17ea | 983 | case elfcpp::R_X86_64_TPOFF32: // Local-exec |
2e30d253 ILT |
984 | // FIXME: If generating a shared object, we need to copy |
985 | // this relocation into the object. | |
e041f13d | 986 | gold_assert(is_final); |
2e30d253 ILT |
987 | break; |
988 | ||
e041f13d ILT |
989 | case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec |
990 | // FIXME: If not relaxing to LE, we need to generate a | |
991 | // TPOFF64 reloc. | |
992 | if (optimized_type != tls::TLSOPT_TO_LE) | |
993 | unsupported_reloc_global(object, r_type, gsym); | |
994 | break; | |
995 | ||
996 | case elfcpp::R_X86_64_TLSLD: // Local-dynamic | |
0ffd9845 ILT |
997 | case elfcpp::R_X86_64_DTPOFF32: |
998 | case elfcpp::R_X86_64_DTPOFF64: | |
e041f13d ILT |
999 | // FIXME: If not relaxing to LE, we need to generate a |
1000 | // DTPMOD64 reloc. | |
1001 | if (optimized_type != tls::TLSOPT_TO_LE) | |
1002 | unsupported_reloc_global(object, r_type, gsym); | |
1003 | break; | |
1004 | ||
0ffd9845 | 1005 | |
e041f13d | 1006 | case elfcpp::R_X86_64_TLSGD: // General-dynamic |
d61c17ea ILT |
1007 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: |
1008 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
e041f13d ILT |
1009 | // FIXME: If not relaxing to LE, we need to generate |
1010 | // DTPMOD64 and DTPOFF64, or TLSDESC, relocs. | |
1011 | if (optimized_type != tls::TLSOPT_TO_LE) | |
1012 | unsupported_reloc_global(object, r_type, gsym); | |
2e30d253 | 1013 | break; |
e041f13d ILT |
1014 | |
1015 | default: | |
1016 | gold_unreachable(); | |
2e30d253 ILT |
1017 | } |
1018 | } | |
1019 | break; | |
e822f2b1 ILT |
1020 | case elfcpp::R_X86_64_SIZE32: // TODO(csilvers): correct? |
1021 | case elfcpp::R_X86_64_SIZE64: // TODO(csilvers): correct? | |
2e30d253 | 1022 | default: |
75f2446e ILT |
1023 | gold_error(_("%s: unsupported reloc %u against global symbol %s"), |
1024 | object->name().c_str(), r_type, gsym->name()); | |
2e30d253 ILT |
1025 | break; |
1026 | } | |
1027 | } | |
1028 | ||
1029 | // Scan relocations for a section. | |
1030 | ||
1031 | void | |
1032 | Target_x86_64::scan_relocs(const General_options& options, | |
d61c17ea ILT |
1033 | Symbol_table* symtab, |
1034 | Layout* layout, | |
1035 | Sized_relobj<64, false>* object, | |
1036 | unsigned int data_shndx, | |
1037 | unsigned int sh_type, | |
1038 | const unsigned char* prelocs, | |
1039 | size_t reloc_count, | |
1040 | size_t local_symbol_count, | |
1041 | const unsigned char* plocal_symbols, | |
1042 | Symbol** global_symbols) | |
2e30d253 ILT |
1043 | { |
1044 | if (sh_type == elfcpp::SHT_REL) | |
1045 | { | |
75f2446e ILT |
1046 | gold_error(_("%s: unsupported REL reloc section"), |
1047 | object->name().c_str()); | |
1048 | return; | |
2e30d253 ILT |
1049 | } |
1050 | ||
1051 | gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA, | |
1052 | Target_x86_64::Scan>( | |
1053 | options, | |
1054 | symtab, | |
1055 | layout, | |
1056 | this, | |
1057 | object, | |
1058 | data_shndx, | |
1059 | prelocs, | |
1060 | reloc_count, | |
1061 | local_symbol_count, | |
1062 | plocal_symbols, | |
1063 | global_symbols); | |
1064 | } | |
1065 | ||
1066 | // Finalize the sections. | |
1067 | ||
1068 | void | |
1069 | Target_x86_64::do_finalize_sections(Layout* layout) | |
1070 | { | |
1071 | // Fill in some more dynamic tags. | |
1072 | Output_data_dynamic* const odyn = layout->dynamic_data(); | |
1073 | if (odyn != NULL) | |
1074 | { | |
1075 | if (this->got_plt_ != NULL) | |
1076 | odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); | |
1077 | ||
1078 | if (this->plt_ != NULL) | |
1079 | { | |
1080 | const Output_data* od = this->plt_->rel_plt(); | |
1081 | odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); | |
1082 | odyn->add_section_address(elfcpp::DT_JMPREL, od); | |
1083 | odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA); | |
1084 | } | |
1085 | ||
0ffd9845 | 1086 | if (this->rela_dyn_ != NULL) |
2e30d253 | 1087 | { |
0ffd9845 | 1088 | const Output_data* od = this->rela_dyn_; |
2e30d253 | 1089 | odyn->add_section_address(elfcpp::DT_RELA, od); |
e84992bb | 1090 | odyn->add_section_size(elfcpp::DT_RELASZ, od); |
2e30d253 | 1091 | odyn->add_constant(elfcpp::DT_RELAENT, |
e84992bb | 1092 | elfcpp::Elf_sizes<64>::rela_size); |
2e30d253 ILT |
1093 | } |
1094 | ||
1095 | if (!parameters->output_is_shared()) | |
1096 | { | |
1097 | // The value of the DT_DEBUG tag is filled in by the dynamic | |
1098 | // linker at run time, and used by the debugger. | |
1099 | odyn->add_constant(elfcpp::DT_DEBUG, 0); | |
1100 | } | |
1101 | } | |
1102 | ||
1103 | // Emit any relocs we saved in an attempt to avoid generating COPY | |
1104 | // relocs. | |
1105 | if (this->copy_relocs_ == NULL) | |
1106 | return; | |
1107 | if (this->copy_relocs_->any_to_emit()) | |
1108 | { | |
0ffd9845 ILT |
1109 | Reloc_section* rela_dyn = this->rela_dyn_section(layout); |
1110 | this->copy_relocs_->emit(rela_dyn); | |
2e30d253 ILT |
1111 | } |
1112 | delete this->copy_relocs_; | |
1113 | this->copy_relocs_ = NULL; | |
1114 | } | |
1115 | ||
1116 | // Perform a relocation. | |
1117 | ||
1118 | inline bool | |
1119 | Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, | |
1120 | Target_x86_64* target, | |
1121 | size_t relnum, | |
0ffd9845 | 1122 | const elfcpp::Rela<64, false>& rela, |
2e30d253 ILT |
1123 | unsigned int r_type, |
1124 | const Sized_symbol<64>* gsym, | |
1125 | const Symbol_value<64>* psymval, | |
1126 | unsigned char* view, | |
1127 | elfcpp::Elf_types<64>::Elf_Addr address, | |
1128 | off_t view_size) | |
1129 | { | |
1130 | if (this->skip_call_tls_get_addr_) | |
1131 | { | |
1132 | if (r_type != elfcpp::R_X86_64_PLT32 | |
1133 | || gsym == NULL | |
0ffd9845 | 1134 | || strcmp(gsym->name(), "__tls_get_addr") != 0) |
2e30d253 | 1135 | { |
75f2446e ILT |
1136 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
1137 | _("missing expected TLS relocation")); | |
1138 | } | |
1139 | else | |
1140 | { | |
1141 | this->skip_call_tls_get_addr_ = false; | |
1142 | return false; | |
2e30d253 | 1143 | } |
2e30d253 ILT |
1144 | } |
1145 | ||
1146 | // Pick the value to use for symbols defined in shared objects. | |
1147 | Symbol_value<64> symval; | |
1148 | if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset()) | |
1149 | { | |
1150 | symval.set_output_value(target->plt_section()->address() | |
1151 | + gsym->plt_offset()); | |
1152 | psymval = &symval; | |
1153 | } | |
1154 | ||
1155 | const Sized_relobj<64, false>* object = relinfo->object; | |
0ffd9845 ILT |
1156 | const elfcpp::Elf_Xword addend = rela.get_r_addend(); |
1157 | ||
1158 | // Get the GOT offset if needed. | |
1159 | bool have_got_offset = false; | |
1160 | unsigned int got_offset = 0; | |
1161 | switch (r_type) | |
1162 | { | |
1163 | case elfcpp::R_X86_64_GOT32: | |
1164 | case elfcpp::R_X86_64_GOT64: | |
1165 | case elfcpp::R_X86_64_GOTPLT64: | |
1166 | case elfcpp::R_X86_64_GOTPCREL: | |
1167 | case elfcpp::R_X86_64_GOTPCREL64: | |
1168 | if (gsym != NULL) | |
1169 | { | |
1170 | gold_assert(gsym->has_got_offset()); | |
1171 | got_offset = gsym->got_offset(); | |
1172 | } | |
1173 | else | |
1174 | { | |
1175 | unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); | |
1176 | got_offset = object->local_got_offset(r_sym); | |
1177 | } | |
1178 | have_got_offset = true; | |
1179 | break; | |
1180 | ||
1181 | default: | |
1182 | break; | |
1183 | } | |
2e30d253 ILT |
1184 | |
1185 | switch (r_type) | |
1186 | { | |
1187 | case elfcpp::R_X86_64_NONE: | |
e822f2b1 ILT |
1188 | case elfcpp::R_386_GNU_VTINHERIT: |
1189 | case elfcpp::R_386_GNU_VTENTRY: | |
2e30d253 ILT |
1190 | break; |
1191 | ||
1192 | case elfcpp::R_X86_64_64: | |
1193 | Relocate_functions<64, false>::rela64(view, object, psymval, addend); | |
1194 | break; | |
1195 | ||
1196 | case elfcpp::R_X86_64_PC64: | |
1197 | Relocate_functions<64, false>::pcrela64(view, object, psymval, addend, | |
1198 | address); | |
1199 | break; | |
1200 | ||
1201 | case elfcpp::R_X86_64_32: | |
7bb3655e ILT |
1202 | // FIXME: we need to verify that value + addend fits into 32 bits: |
1203 | // uint64_t x = value + addend; | |
1204 | // x == static_cast<uint64_t>(static_cast<uint32_t>(x)) | |
1205 | // Likewise for other <=32-bit relocations (but see R_X86_64_32S). | |
2e30d253 ILT |
1206 | Relocate_functions<64, false>::rela32(view, object, psymval, addend); |
1207 | break; | |
1208 | ||
1209 | case elfcpp::R_X86_64_32S: | |
7bb3655e ILT |
1210 | // FIXME: we need to verify that value + addend fits into 32 bits: |
1211 | // int64_t x = value + addend; // note this quantity is signed! | |
1212 | // x == static_cast<int64_t>(static_cast<int32_t>(x)) | |
2e30d253 ILT |
1213 | Relocate_functions<64, false>::rela32(view, object, psymval, addend); |
1214 | break; | |
1215 | ||
1216 | case elfcpp::R_X86_64_PC32: | |
1217 | Relocate_functions<64, false>::pcrela32(view, object, psymval, addend, | |
1218 | address); | |
1219 | break; | |
1220 | ||
1221 | case elfcpp::R_X86_64_16: | |
1222 | Relocate_functions<64, false>::rela16(view, object, psymval, addend); | |
1223 | break; | |
1224 | ||
1225 | case elfcpp::R_X86_64_PC16: | |
1226 | Relocate_functions<64, false>::pcrela16(view, object, psymval, addend, | |
1227 | address); | |
1228 | break; | |
1229 | ||
1230 | case elfcpp::R_X86_64_8: | |
1231 | Relocate_functions<64, false>::rela8(view, object, psymval, addend); | |
1232 | break; | |
1233 | ||
1234 | case elfcpp::R_X86_64_PC8: | |
1235 | Relocate_functions<64, false>::pcrela8(view, object, psymval, addend, | |
1236 | address); | |
1237 | break; | |
1238 | ||
1239 | case elfcpp::R_X86_64_PLT32: | |
1240 | gold_assert(gsym->has_plt_offset() | |
1241 | || gsym->final_value_is_known()); | |
1242 | Relocate_functions<64, false>::pcrela32(view, object, psymval, addend, | |
1243 | address); | |
1244 | break; | |
1245 | ||
1246 | case elfcpp::R_X86_64_GOT32: | |
0ffd9845 ILT |
1247 | gold_assert(have_got_offset); |
1248 | Relocate_functions<64, false>::rela32(view, got_offset, addend); | |
2e30d253 ILT |
1249 | break; |
1250 | ||
e822f2b1 ILT |
1251 | case elfcpp::R_X86_64_GOTPC32: |
1252 | { | |
1253 | gold_assert(gsym); | |
1254 | elfcpp::Elf_types<64>::Elf_Addr value; | |
1255 | value = target->got_section(NULL, NULL)->address(); | |
1256 | Relocate_functions<64, false>::pcrela32(view, value, addend, address); | |
1257 | } | |
1258 | break; | |
1259 | ||
1260 | case elfcpp::R_X86_64_GOT64: | |
1261 | // The ABI doc says "Like GOT64, but indicates a PLT entry is needed." | |
1262 | // Since we always add a PLT entry, this is equivalent. | |
1263 | case elfcpp::R_X86_64_GOTPLT64: // TODO(csilvers): correct? | |
0ffd9845 ILT |
1264 | gold_assert(have_got_offset); |
1265 | Relocate_functions<64, false>::rela64(view, got_offset, addend); | |
e822f2b1 ILT |
1266 | break; |
1267 | ||
1268 | case elfcpp::R_X86_64_GOTPC64: | |
1269 | { | |
1270 | gold_assert(gsym); | |
1271 | elfcpp::Elf_types<64>::Elf_Addr value; | |
1272 | value = target->got_section(NULL, NULL)->address(); | |
1273 | Relocate_functions<64, false>::pcrela64(view, value, addend, address); | |
1274 | } | |
1275 | break; | |
1276 | ||
2e30d253 ILT |
1277 | case elfcpp::R_X86_64_GOTOFF64: |
1278 | { | |
1279 | elfcpp::Elf_types<64>::Elf_Addr value; | |
1280 | value = (psymval->value(object, 0) | |
1281 | - target->got_section(NULL, NULL)->address()); | |
1282 | Relocate_functions<64, false>::rela64(view, value, addend); | |
1283 | } | |
1284 | break; | |
1285 | ||
1286 | case elfcpp::R_X86_64_GOTPCREL: | |
1287 | { | |
0ffd9845 ILT |
1288 | gold_assert(have_got_offset); |
1289 | elfcpp::Elf_types<64>::Elf_Addr value; | |
1290 | value = target->got_section(NULL, NULL)->address() + got_offset; | |
1291 | Relocate_functions<64, false>::pcrela32(view, value, addend, address); | |
2e30d253 ILT |
1292 | } |
1293 | break; | |
1294 | ||
e822f2b1 ILT |
1295 | case elfcpp::R_X86_64_GOTPCREL64: |
1296 | { | |
0ffd9845 ILT |
1297 | gold_assert(have_got_offset); |
1298 | elfcpp::Elf_types<64>::Elf_Addr value; | |
1299 | value = target->got_section(NULL, NULL)->address() + got_offset; | |
1300 | Relocate_functions<64, false>::pcrela64(view, value, addend, address); | |
e822f2b1 ILT |
1301 | } |
1302 | break; | |
1303 | ||
2e30d253 ILT |
1304 | case elfcpp::R_X86_64_COPY: |
1305 | case elfcpp::R_X86_64_GLOB_DAT: | |
1306 | case elfcpp::R_X86_64_JUMP_SLOT: | |
1307 | case elfcpp::R_X86_64_RELATIVE: | |
d61c17ea | 1308 | // These are outstanding tls relocs, which are unexpected when linking |
2e30d253 | 1309 | case elfcpp::R_X86_64_TPOFF64: |
2e30d253 | 1310 | case elfcpp::R_X86_64_DTPMOD64: |
2e30d253 | 1311 | case elfcpp::R_X86_64_TLSDESC: |
75f2446e ILT |
1312 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
1313 | _("unexpected reloc %u in object file"), | |
1314 | r_type); | |
2e30d253 ILT |
1315 | break; |
1316 | ||
d61c17ea | 1317 | // These are initial tls relocs, which are expected when linking |
e041f13d ILT |
1318 | case elfcpp::R_X86_64_TLSGD: |
1319 | case elfcpp::R_X86_64_TLSLD: | |
1320 | case elfcpp::R_X86_64_GOTTPOFF: | |
1321 | case elfcpp::R_X86_64_TPOFF32: | |
1322 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: | |
1323 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
0ffd9845 ILT |
1324 | case elfcpp::R_X86_64_DTPOFF32: |
1325 | case elfcpp::R_X86_64_DTPOFF64: | |
1326 | this->relocate_tls(relinfo, relnum, rela, r_type, gsym, psymval, view, | |
2e30d253 ILT |
1327 | address, view_size); |
1328 | break; | |
2e30d253 | 1329 | |
e822f2b1 ILT |
1330 | case elfcpp::R_X86_64_SIZE32: // TODO(csilvers): correct? |
1331 | case elfcpp::R_X86_64_SIZE64: // TODO(csilvers): correct? | |
1332 | case elfcpp::R_X86_64_PLTOFF64: // TODO(csilvers): implement me! | |
2e30d253 | 1333 | default: |
75f2446e ILT |
1334 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
1335 | _("unsupported reloc %u"), | |
1336 | r_type); | |
2e30d253 ILT |
1337 | break; |
1338 | } | |
1339 | ||
1340 | return true; | |
1341 | } | |
1342 | ||
1343 | // Perform a TLS relocation. | |
1344 | ||
1345 | inline void | |
d61c17ea ILT |
1346 | Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, |
1347 | size_t relnum, | |
72ec2876 | 1348 | const elfcpp::Rela<64, false>& rela, |
d61c17ea ILT |
1349 | unsigned int r_type, |
1350 | const Sized_symbol<64>* gsym, | |
1351 | const Symbol_value<64>* psymval, | |
1352 | unsigned char* view, | |
2e30d253 | 1353 | elfcpp::Elf_types<64>::Elf_Addr, |
d61c17ea | 1354 | off_t view_size) |
2e30d253 | 1355 | { |
2e30d253 ILT |
1356 | Output_segment* tls_segment = relinfo->layout->tls_segment(); |
1357 | if (tls_segment == NULL) | |
1358 | { | |
72ec2876 | 1359 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
75f2446e ILT |
1360 | _("TLS reloc but no TLS segment")); |
1361 | return; | |
2e30d253 ILT |
1362 | } |
1363 | ||
1364 | elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0); | |
1365 | ||
1366 | const bool is_final = (gsym == NULL | |
1367 | ? !parameters->output_is_shared() | |
1368 | : gsym->final_value_is_known()); | |
e041f13d ILT |
1369 | const tls::Tls_optimization optimized_type |
1370 | = Target_x86_64::optimize_tls_reloc(is_final, r_type); | |
2e30d253 ILT |
1371 | switch (r_type) |
1372 | { | |
d61c17ea | 1373 | case elfcpp::R_X86_64_TPOFF32: // Local-exec reloc |
2e30d253 | 1374 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
d61c17ea | 1375 | Relocate_functions<64, false>::rel32(view, value); |
2e30d253 ILT |
1376 | break; |
1377 | ||
d61c17ea | 1378 | case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec reloc |
e041f13d | 1379 | if (optimized_type == tls::TLSOPT_TO_LE) |
2e30d253 ILT |
1380 | { |
1381 | Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, | |
72ec2876 | 1382 | rela, r_type, value, view, |
d61c17ea | 1383 | view_size); |
2e30d253 ILT |
1384 | break; |
1385 | } | |
72ec2876 | 1386 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
75f2446e ILT |
1387 | _("unsupported reloc type %u"), |
1388 | r_type); | |
2e30d253 ILT |
1389 | break; |
1390 | ||
d61c17ea | 1391 | case elfcpp::R_X86_64_TLSGD: |
e041f13d ILT |
1392 | case elfcpp::R_X86_64_GOTPC32_TLSDESC: |
1393 | case elfcpp::R_X86_64_TLSDESC_CALL: | |
1394 | if (optimized_type == tls::TLSOPT_TO_LE) | |
2e30d253 ILT |
1395 | { |
1396 | this->tls_gd_to_le(relinfo, relnum, tls_segment, | |
72ec2876 | 1397 | rela, r_type, value, view, |
2e30d253 ILT |
1398 | view_size); |
1399 | break; | |
1400 | } | |
72ec2876 | 1401 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
75f2446e | 1402 | _("unsupported reloc %u"), r_type); |
2e30d253 ILT |
1403 | break; |
1404 | ||
d61c17ea | 1405 | case elfcpp::R_X86_64_TLSLD: |
e041f13d ILT |
1406 | if (optimized_type == tls::TLSOPT_TO_LE) |
1407 | { | |
72ec2876 ILT |
1408 | this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type, |
1409 | value, view, view_size); | |
1410 | break; | |
e041f13d | 1411 | } |
72ec2876 | 1412 | gold_error_at_location(relinfo, relnum, rela.get_r_offset(), |
75f2446e | 1413 | _("unsupported reloc %u"), r_type); |
2e30d253 | 1414 | break; |
0ffd9845 ILT |
1415 | |
1416 | case elfcpp::R_X86_64_DTPOFF32: | |
e041f13d | 1417 | if (optimized_type == tls::TLSOPT_TO_LE) |
0ffd9845 ILT |
1418 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
1419 | else | |
1420 | value = value - tls_segment->vaddr(); | |
1421 | Relocate_functions<64, false>::rel32(view, value); | |
1422 | break; | |
1423 | ||
1424 | case elfcpp::R_X86_64_DTPOFF64: | |
e041f13d | 1425 | if (optimized_type == tls::TLSOPT_TO_LE) |
0ffd9845 ILT |
1426 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
1427 | else | |
1428 | value = value - tls_segment->vaddr(); | |
1429 | Relocate_functions<64, false>::rel64(view, value); | |
1430 | break; | |
2e30d253 | 1431 | } |
2e30d253 ILT |
1432 | } |
1433 | ||
1434 | // Do a relocation in which we convert a TLS Initial-Exec to a | |
1435 | // Local-Exec. | |
1436 | ||
1437 | inline void | |
d61c17ea ILT |
1438 | Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo, |
1439 | size_t relnum, | |
1440 | Output_segment* tls_segment, | |
72ec2876 | 1441 | const elfcpp::Rela<64, false>& rela, |
d61c17ea ILT |
1442 | unsigned int, |
1443 | elfcpp::Elf_types<64>::Elf_Addr value, | |
1444 | unsigned char* view, | |
1445 | off_t view_size) | |
2e30d253 | 1446 | { |
0ffd9845 | 1447 | // We need to examine the opcodes to figure out which instruction we |
2e30d253 | 1448 | // are looking at. |
2e30d253 | 1449 | |
0ffd9845 ILT |
1450 | // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg |
1451 | // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg | |
1452 | ||
72ec2876 ILT |
1453 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); |
1454 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); | |
d61c17ea | 1455 | |
0ffd9845 ILT |
1456 | unsigned char op1 = view[-3]; |
1457 | unsigned char op2 = view[-2]; | |
1458 | unsigned char op3 = view[-1]; | |
1459 | unsigned char reg = op3 >> 3; | |
1460 | ||
1461 | if (op2 == 0x8b) | |
1462 | { | |
1463 | // movq | |
1464 | if (op1 == 0x4c) | |
1465 | view[-3] = 0x49; | |
1466 | view[-2] = 0xc7; | |
1467 | view[-1] = 0xc0 | reg; | |
1468 | } | |
1469 | else if (reg == 4) | |
d61c17ea | 1470 | { |
0ffd9845 ILT |
1471 | // Special handling for %rsp. |
1472 | if (op1 == 0x4c) | |
1473 | view[-3] = 0x49; | |
1474 | view[-2] = 0x81; | |
1475 | view[-1] = 0xc0 | reg; | |
2e30d253 ILT |
1476 | } |
1477 | else | |
1478 | { | |
0ffd9845 ILT |
1479 | // addq |
1480 | if (op1 == 0x4c) | |
1481 | view[-3] = 0x4d; | |
1482 | view[-2] = 0x8d; | |
1483 | view[-1] = 0x80 | reg | (reg << 3); | |
2e30d253 ILT |
1484 | } |
1485 | ||
d61c17ea | 1486 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
0ffd9845 | 1487 | Relocate_functions<64, false>::rela32(view, value, 0); |
2e30d253 ILT |
1488 | } |
1489 | ||
e041f13d | 1490 | // Do a relocation in which we convert a TLS General-Dynamic to a |
2e30d253 ILT |
1491 | // Local-Exec. |
1492 | ||
1493 | inline void | |
d61c17ea ILT |
1494 | Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo, |
1495 | size_t relnum, | |
1496 | Output_segment* tls_segment, | |
72ec2876 | 1497 | const elfcpp::Rela<64, false>& rela, |
d61c17ea ILT |
1498 | unsigned int, |
1499 | elfcpp::Elf_types<64>::Elf_Addr value, | |
1500 | unsigned char* view, | |
1501 | off_t view_size) | |
2e30d253 | 1502 | { |
0ffd9845 ILT |
1503 | // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; |
1504 | // .word 0x6666; rex64; call __tls_get_addr | |
1505 | // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax | |
2e30d253 | 1506 | |
72ec2876 ILT |
1507 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4); |
1508 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); | |
2e30d253 | 1509 | |
72ec2876 ILT |
1510 | tls::check_tls(relinfo, relnum, rela.get_r_offset(), |
1511 | (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); | |
1512 | tls::check_tls(relinfo, relnum, rela.get_r_offset(), | |
1513 | (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0)); | |
2e30d253 | 1514 | |
0ffd9845 | 1515 | memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16); |
2e30d253 | 1516 | |
0ffd9845 ILT |
1517 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
1518 | Relocate_functions<64, false>::rela32(view + 8, value, 0); | |
2e30d253 ILT |
1519 | |
1520 | // The next reloc should be a PLT32 reloc against __tls_get_addr. | |
1521 | // We can skip it. | |
1522 | this->skip_call_tls_get_addr_ = true; | |
2e30d253 ILT |
1523 | } |
1524 | ||
2e30d253 | 1525 | inline void |
72ec2876 ILT |
1526 | Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo, |
1527 | size_t relnum, | |
1528 | Output_segment*, | |
1529 | const elfcpp::Rela<64, false>& rela, | |
1530 | unsigned int, | |
1531 | elfcpp::Elf_types<64>::Elf_Addr, | |
1532 | unsigned char* view, | |
1533 | off_t view_size) | |
2e30d253 | 1534 | { |
72ec2876 ILT |
1535 | // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; |
1536 | // ... leq foo@dtpoff(%rax),%reg | |
1537 | // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx | |
2e30d253 | 1538 | |
72ec2876 ILT |
1539 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); |
1540 | tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9); | |
2e30d253 | 1541 | |
72ec2876 ILT |
1542 | tls::check_tls(relinfo, relnum, rela.get_r_offset(), |
1543 | view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d); | |
1544 | ||
1545 | tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8); | |
1546 | ||
1547 | memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12); | |
1548 | ||
1549 | // The next reloc should be a PLT32 reloc against __tls_get_addr. | |
1550 | // We can skip it. | |
1551 | this->skip_call_tls_get_addr_ = true; | |
2e30d253 ILT |
1552 | } |
1553 | ||
1554 | // Relocate section data. | |
1555 | ||
1556 | void | |
1557 | Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo, | |
d61c17ea ILT |
1558 | unsigned int sh_type, |
1559 | const unsigned char* prelocs, | |
1560 | size_t reloc_count, | |
1561 | unsigned char* view, | |
1562 | elfcpp::Elf_types<64>::Elf_Addr address, | |
1563 | off_t view_size) | |
2e30d253 ILT |
1564 | { |
1565 | gold_assert(sh_type == elfcpp::SHT_RELA); | |
1566 | ||
1567 | gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA, | |
1568 | Target_x86_64::Relocate>( | |
1569 | relinfo, | |
1570 | this, | |
1571 | prelocs, | |
1572 | reloc_count, | |
1573 | view, | |
1574 | address, | |
1575 | view_size); | |
1576 | } | |
1577 | ||
4fb6c25d ILT |
1578 | // Return the value to use for a dynamic which requires special |
1579 | // treatment. This is how we support equality comparisons of function | |
1580 | // pointers across shared library boundaries, as described in the | |
1581 | // processor specific ABI supplement. | |
1582 | ||
1583 | uint64_t | |
1584 | Target_x86_64::do_dynsym_value(const Symbol* gsym) const | |
1585 | { | |
1586 | gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); | |
1587 | return this->plt_section()->address() + gsym->plt_offset(); | |
1588 | } | |
1589 | ||
2e30d253 ILT |
1590 | // Return a string used to fill a code section with nops to take up |
1591 | // the specified length. | |
1592 | ||
1593 | std::string | |
1594 | Target_x86_64::do_code_fill(off_t length) | |
1595 | { | |
1596 | if (length >= 16) | |
1597 | { | |
1598 | // Build a jmpq instruction to skip over the bytes. | |
1599 | unsigned char jmp[5]; | |
1600 | jmp[0] = 0xe9; | |
1601 | elfcpp::Swap_unaligned<64, false>::writeval(jmp + 1, length - 5); | |
1602 | return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) | |
1603 | + std::string(length - 5, '\0')); | |
1604 | } | |
1605 | ||
1606 | // Nop sequences of various lengths. | |
1607 | const char nop1[1] = { 0x90 }; // nop | |
1608 | const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax | |
1609 | const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi | |
1610 | const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi | |
1611 | const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop | |
1612 | 0x00 }; // leal 0(%esi,1),%esi | |
1613 | const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi | |
1614 | 0x00, 0x00 }; | |
1615 | const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi | |
1616 | 0x00, 0x00, 0x00 }; | |
1617 | const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop | |
1618 | 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi | |
1619 | const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi | |
1620 | 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi | |
1621 | 0x00 }; | |
1622 | const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi | |
1623 | 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi | |
1624 | 0x00, 0x00 }; | |
1625 | const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi | |
1626 | 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi | |
1627 | 0x00, 0x00, 0x00 }; | |
1628 | const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi | |
1629 | 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi | |
1630 | 0x00, 0x00, 0x00, 0x00 }; | |
1631 | const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi | |
1632 | 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi | |
1633 | 0x27, 0x00, 0x00, 0x00, | |
1634 | 0x00 }; | |
1635 | const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi | |
1636 | 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi | |
1637 | 0xbc, 0x27, 0x00, 0x00, | |
1638 | 0x00, 0x00 }; | |
1639 | const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15 | |
1640 | 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,... | |
1641 | 0x90, 0x90, 0x90, 0x90, | |
1642 | 0x90, 0x90, 0x90 }; | |
1643 | ||
1644 | const char* nops[16] = { | |
1645 | NULL, | |
1646 | nop1, nop2, nop3, nop4, nop5, nop6, nop7, | |
1647 | nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 | |
1648 | }; | |
1649 | ||
1650 | return std::string(nops[length], length); | |
1651 | } | |
1652 | ||
1653 | // The selector for x86_64 object files. | |
1654 | ||
1655 | class Target_selector_x86_64 : public Target_selector | |
1656 | { | |
1657 | public: | |
1658 | Target_selector_x86_64() | |
1659 | : Target_selector(elfcpp::EM_X86_64, 64, false) | |
1660 | { } | |
1661 | ||
1662 | Target* | |
1663 | recognize(int machine, int osabi, int abiversion); | |
1664 | ||
1665 | private: | |
1666 | Target_x86_64* target_; | |
1667 | }; | |
1668 | ||
1669 | // Recognize an x86_64 object file when we already know that the machine | |
1670 | // number is EM_X86_64. | |
1671 | ||
1672 | Target* | |
1673 | Target_selector_x86_64::recognize(int, int, int) | |
1674 | { | |
1675 | if (this->target_ == NULL) | |
1676 | this->target_ = new Target_x86_64(); | |
1677 | return this->target_; | |
1678 | } | |
1679 | ||
1680 | Target_selector_x86_64 target_selector_x86_64; | |
1681 | ||
1682 | } // End anonymous namespace. |