gold: x86_64-nacl: Correct 9-byte nop sequence to match what the assembler generates.
[deliverable/binutils-gdb.git] / gold / x86_64.cc
1 // x86_64.cc -- x86_64 target support for gold.
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
6
7 // This file is part of gold.
8
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
13
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
18
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
23
24 #include "gold.h"
25
26 #include <cstring>
27
28 #include "elfcpp.h"
29 #include "dwarf.h"
30 #include "parameters.h"
31 #include "reloc.h"
32 #include "x86_64.h"
33 #include "object.h"
34 #include "symtab.h"
35 #include "layout.h"
36 #include "output.h"
37 #include "copy-relocs.h"
38 #include "target.h"
39 #include "target-reloc.h"
40 #include "target-select.h"
41 #include "tls.h"
42 #include "freebsd.h"
43 #include "nacl.h"
44 #include "gc.h"
45 #include "icf.h"
46
47 namespace
48 {
49
50 using namespace gold;
51
52 // A class to handle the PLT data.
53 // This is an abstract base class that handles most of the linker details
54 // but does not know the actual contents of PLT entries. The derived
55 // classes below fill in those details.
56
57 template<int size>
58 class Output_data_plt_x86_64 : public Output_section_data
59 {
60 public:
61 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
62
63 Output_data_plt_x86_64(Layout* layout, uint64_t addralign,
64 Output_data_got<64, false>* got,
65 Output_data_space* got_plt,
66 Output_data_space* got_irelative)
67 : Output_section_data(addralign), layout_(layout), tlsdesc_rel_(NULL),
68 irelative_rel_(NULL), got_(got), got_plt_(got_plt),
69 got_irelative_(got_irelative), count_(0), irelative_count_(0),
70 tlsdesc_got_offset_(-1U), free_list_()
71 { this->init(layout); }
72
73 Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size,
74 Output_data_got<64, false>* got,
75 Output_data_space* got_plt,
76 Output_data_space* got_irelative,
77 unsigned int plt_count)
78 : Output_section_data((plt_count + 1) * plt_entry_size,
79 plt_entry_size, false),
80 layout_(layout), tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
81 got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
82 irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
83 {
84 this->init(layout);
85
86 // Initialize the free list and reserve the first entry.
87 this->free_list_.init((plt_count + 1) * plt_entry_size, false);
88 this->free_list_.remove(0, plt_entry_size);
89 }
90
91 // Initialize the PLT section.
92 void
93 init(Layout* layout);
94
95 // Add an entry to the PLT.
96 void
97 add_entry(Symbol_table*, Layout*, Symbol* gsym);
98
99 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
100 unsigned int
101 add_local_ifunc_entry(Symbol_table* symtab, Layout*,
102 Sized_relobj_file<size, false>* relobj,
103 unsigned int local_sym_index);
104
105 // Add the relocation for a PLT entry.
106 void
107 add_relocation(Symbol_table*, Layout*, Symbol* gsym,
108 unsigned int got_offset);
109
110 // Add the reserved TLSDESC_PLT entry to the PLT.
111 void
112 reserve_tlsdesc_entry(unsigned int got_offset)
113 { this->tlsdesc_got_offset_ = got_offset; }
114
115 // Return true if a TLSDESC_PLT entry has been reserved.
116 bool
117 has_tlsdesc_entry() const
118 { return this->tlsdesc_got_offset_ != -1U; }
119
120 // Return the GOT offset for the reserved TLSDESC_PLT entry.
121 unsigned int
122 get_tlsdesc_got_offset() const
123 { return this->tlsdesc_got_offset_; }
124
125 // Return the offset of the reserved TLSDESC_PLT entry.
126 unsigned int
127 get_tlsdesc_plt_offset() const
128 {
129 return ((this->count_ + this->irelative_count_ + 1)
130 * this->get_plt_entry_size());
131 }
132
133 // Return the .rela.plt section data.
134 Reloc_section*
135 rela_plt()
136 { return this->rel_; }
137
138 // Return where the TLSDESC relocations should go.
139 Reloc_section*
140 rela_tlsdesc(Layout*);
141
142 // Return where the IRELATIVE relocations should go in the PLT
143 // relocations.
144 Reloc_section*
145 rela_irelative(Symbol_table*, Layout*);
146
147 // Return whether we created a section for IRELATIVE relocations.
148 bool
149 has_irelative_section() const
150 { return this->irelative_rel_ != NULL; }
151
152 // Return the number of PLT entries.
153 unsigned int
154 entry_count() const
155 { return this->count_ + this->irelative_count_; }
156
157 // Return the offset of the first non-reserved PLT entry.
158 unsigned int
159 first_plt_entry_offset()
160 { return this->get_plt_entry_size(); }
161
162 // Return the size of a PLT entry.
163 unsigned int
164 get_plt_entry_size() const
165 { return this->do_get_plt_entry_size(); }
166
167 // Reserve a slot in the PLT for an existing symbol in an incremental update.
168 void
169 reserve_slot(unsigned int plt_index)
170 {
171 this->free_list_.remove((plt_index + 1) * this->get_plt_entry_size(),
172 (plt_index + 2) * this->get_plt_entry_size());
173 }
174
175 // Return the PLT address to use for a global symbol.
176 uint64_t
177 address_for_global(const Symbol*);
178
179 // Return the PLT address to use for a local symbol.
180 uint64_t
181 address_for_local(const Relobj*, unsigned int symndx);
182
183 // Add .eh_frame information for the PLT.
184 void
185 add_eh_frame(Layout* layout)
186 { this->do_add_eh_frame(layout); }
187
188 protected:
189 // Fill in the first PLT entry.
190 void
191 fill_first_plt_entry(unsigned char* pov,
192 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
193 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
194 { this->do_fill_first_plt_entry(pov, got_address, plt_address); }
195
196 // Fill in a normal PLT entry. Returns the offset into the entry that
197 // should be the initial GOT slot value.
198 unsigned int
199 fill_plt_entry(unsigned char* pov,
200 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
201 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
202 unsigned int got_offset,
203 unsigned int plt_offset,
204 unsigned int plt_index)
205 {
206 return this->do_fill_plt_entry(pov, got_address, plt_address,
207 got_offset, plt_offset, plt_index);
208 }
209
210 // Fill in the reserved TLSDESC PLT entry.
211 void
212 fill_tlsdesc_entry(unsigned char* pov,
213 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
214 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
215 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
216 unsigned int tlsdesc_got_offset,
217 unsigned int plt_offset)
218 {
219 this->do_fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
220 tlsdesc_got_offset, plt_offset);
221 }
222
223 virtual unsigned int
224 do_get_plt_entry_size() const = 0;
225
226 virtual void
227 do_fill_first_plt_entry(unsigned char* pov,
228 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
229 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr)
230 = 0;
231
232 virtual unsigned int
233 do_fill_plt_entry(unsigned char* pov,
234 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
235 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
236 unsigned int got_offset,
237 unsigned int plt_offset,
238 unsigned int plt_index) = 0;
239
240 virtual void
241 do_fill_tlsdesc_entry(unsigned char* pov,
242 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
243 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
244 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
245 unsigned int tlsdesc_got_offset,
246 unsigned int plt_offset) = 0;
247
248 virtual void
249 do_add_eh_frame(Layout* layout) = 0;
250
251 void
252 do_adjust_output_section(Output_section* os);
253
254 // Write to a map file.
255 void
256 do_print_to_mapfile(Mapfile* mapfile) const
257 { mapfile->print_output_data(this, _("** PLT")); }
258
259 // The CIE of the .eh_frame unwind information for the PLT.
260 static const int plt_eh_frame_cie_size = 16;
261 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
262
263 private:
264 // Set the final size.
265 void
266 set_final_data_size();
267
268 // Write out the PLT data.
269 void
270 do_write(Output_file*);
271
272 // A pointer to the Layout class, so that we can find the .dynamic
273 // section when we write out the GOT PLT section.
274 Layout* layout_;
275 // The reloc section.
276 Reloc_section* rel_;
277 // The TLSDESC relocs, if necessary. These must follow the regular
278 // PLT relocs.
279 Reloc_section* tlsdesc_rel_;
280 // The IRELATIVE relocs, if necessary. These must follow the
281 // regular PLT relocations and the TLSDESC relocations.
282 Reloc_section* irelative_rel_;
283 // The .got section.
284 Output_data_got<64, false>* got_;
285 // The .got.plt section.
286 Output_data_space* got_plt_;
287 // The part of the .got.plt section used for IRELATIVE relocs.
288 Output_data_space* got_irelative_;
289 // The number of PLT entries.
290 unsigned int count_;
291 // Number of PLT entries with R_X86_64_IRELATIVE relocs. These
292 // follow the regular PLT entries.
293 unsigned int irelative_count_;
294 // Offset of the reserved TLSDESC_GOT entry when needed.
295 unsigned int tlsdesc_got_offset_;
296 // List of available regions within the section, for incremental
297 // update links.
298 Free_list free_list_;
299 };
300
301 template<int size>
302 class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size>
303 {
304 public:
305 Output_data_plt_x86_64_standard(Layout* layout,
306 Output_data_got<64, false>* got,
307 Output_data_space* got_plt,
308 Output_data_space* got_irelative)
309 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
310 got, got_plt, got_irelative)
311 { }
312
313 Output_data_plt_x86_64_standard(Layout* layout,
314 Output_data_got<64, false>* got,
315 Output_data_space* got_plt,
316 Output_data_space* got_irelative,
317 unsigned int plt_count)
318 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
319 got, got_plt, got_irelative,
320 plt_count)
321 { }
322
323 protected:
324 virtual unsigned int
325 do_get_plt_entry_size() const
326 { return plt_entry_size; }
327
328 virtual void
329 do_add_eh_frame(Layout* layout)
330 {
331 layout->add_eh_frame_for_plt(this,
332 this->plt_eh_frame_cie,
333 this->plt_eh_frame_cie_size,
334 plt_eh_frame_fde,
335 plt_eh_frame_fde_size);
336 }
337
338 virtual void
339 do_fill_first_plt_entry(unsigned char* pov,
340 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
341 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr);
342
343 virtual unsigned int
344 do_fill_plt_entry(unsigned char* pov,
345 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
346 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
347 unsigned int got_offset,
348 unsigned int plt_offset,
349 unsigned int plt_index);
350
351 virtual void
352 do_fill_tlsdesc_entry(unsigned char* pov,
353 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
354 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
355 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
356 unsigned int tlsdesc_got_offset,
357 unsigned int plt_offset);
358
359 private:
360 // The size of an entry in the PLT.
361 static const int plt_entry_size = 16;
362
363 // The first entry in the PLT.
364 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
365 // procedure linkage table for both programs and shared objects."
366 static const unsigned char first_plt_entry[plt_entry_size];
367
368 // Other entries in the PLT for an executable.
369 static const unsigned char plt_entry[plt_entry_size];
370
371 // The reserved TLSDESC entry in the PLT for an executable.
372 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
373
374 // The .eh_frame unwind information for the PLT.
375 static const int plt_eh_frame_fde_size = 32;
376 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
377 };
378
379 // The x86_64 target class.
380 // See the ABI at
381 // http://www.x86-64.org/documentation/abi.pdf
382 // TLS info comes from
383 // http://people.redhat.com/drepper/tls.pdf
384 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
385
386 template<int size>
387 class Target_x86_64 : public Sized_target<size, false>
388 {
389 public:
390 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
391 // uses only Elf64_Rela relocation entries with explicit addends."
392 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
393
394 Target_x86_64(const Target::Target_info* info = &x86_64_info)
395 : Sized_target<size, false>(info),
396 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
397 got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL),
398 rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY),
399 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
400 tls_base_symbol_defined_(false)
401 { }
402
403 // Hook for a new output section.
404 void
405 do_new_output_section(Output_section*) const;
406
407 // Scan the relocations to look for symbol adjustments.
408 void
409 gc_process_relocs(Symbol_table* symtab,
410 Layout* layout,
411 Sized_relobj_file<size, false>* object,
412 unsigned int data_shndx,
413 unsigned int sh_type,
414 const unsigned char* prelocs,
415 size_t reloc_count,
416 Output_section* output_section,
417 bool needs_special_offset_handling,
418 size_t local_symbol_count,
419 const unsigned char* plocal_symbols);
420
421 // Scan the relocations to look for symbol adjustments.
422 void
423 scan_relocs(Symbol_table* symtab,
424 Layout* layout,
425 Sized_relobj_file<size, false>* object,
426 unsigned int data_shndx,
427 unsigned int sh_type,
428 const unsigned char* prelocs,
429 size_t reloc_count,
430 Output_section* output_section,
431 bool needs_special_offset_handling,
432 size_t local_symbol_count,
433 const unsigned char* plocal_symbols);
434
435 // Finalize the sections.
436 void
437 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
438
439 // Return the value to use for a dynamic which requires special
440 // treatment.
441 uint64_t
442 do_dynsym_value(const Symbol*) const;
443
444 // Relocate a section.
445 void
446 relocate_section(const Relocate_info<size, false>*,
447 unsigned int sh_type,
448 const unsigned char* prelocs,
449 size_t reloc_count,
450 Output_section* output_section,
451 bool needs_special_offset_handling,
452 unsigned char* view,
453 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
454 section_size_type view_size,
455 const Reloc_symbol_changes*);
456
457 // Scan the relocs during a relocatable link.
458 void
459 scan_relocatable_relocs(Symbol_table* symtab,
460 Layout* layout,
461 Sized_relobj_file<size, false>* object,
462 unsigned int data_shndx,
463 unsigned int sh_type,
464 const unsigned char* prelocs,
465 size_t reloc_count,
466 Output_section* output_section,
467 bool needs_special_offset_handling,
468 size_t local_symbol_count,
469 const unsigned char* plocal_symbols,
470 Relocatable_relocs*);
471
472 // Emit relocations for a section.
473 void
474 relocate_relocs(
475 const Relocate_info<size, false>*,
476 unsigned int sh_type,
477 const unsigned char* prelocs,
478 size_t reloc_count,
479 Output_section* output_section,
480 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
481 const Relocatable_relocs*,
482 unsigned char* view,
483 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
484 section_size_type view_size,
485 unsigned char* reloc_view,
486 section_size_type reloc_view_size);
487
488 // Return a string used to fill a code section with nops.
489 std::string
490 do_code_fill(section_size_type length) const;
491
492 // Return whether SYM is defined by the ABI.
493 bool
494 do_is_defined_by_abi(const Symbol* sym) const
495 { return strcmp(sym->name(), "__tls_get_addr") == 0; }
496
497 // Return the symbol index to use for a target specific relocation.
498 // The only target specific relocation is R_X86_64_TLSDESC for a
499 // local symbol, which is an absolute reloc.
500 unsigned int
501 do_reloc_symbol_index(void*, unsigned int r_type) const
502 {
503 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
504 return 0;
505 }
506
507 // Return the addend to use for a target specific relocation.
508 uint64_t
509 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
510
511 // Return the PLT section.
512 uint64_t
513 do_plt_address_for_global(const Symbol* gsym) const
514 { return this->plt_section()->address_for_global(gsym); }
515
516 uint64_t
517 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
518 { return this->plt_section()->address_for_local(relobj, symndx); }
519
520 // This function should be defined in targets that can use relocation
521 // types to determine (implemented in local_reloc_may_be_function_pointer
522 // and global_reloc_may_be_function_pointer)
523 // if a function's pointer is taken. ICF uses this in safe mode to only
524 // fold those functions whose pointer is defintely not taken. For x86_64
525 // pie binaries, safe ICF cannot be done by looking at relocation types.
526 bool
527 do_can_check_for_function_pointers() const
528 { return !parameters->options().pie(); }
529
530 // Return the base for a DW_EH_PE_datarel encoding.
531 uint64_t
532 do_ehframe_datarel_base() const;
533
534 // Adjust -fsplit-stack code which calls non-split-stack code.
535 void
536 do_calls_non_split(Relobj* object, unsigned int shndx,
537 section_offset_type fnoffset, section_size_type fnsize,
538 unsigned char* view, section_size_type view_size,
539 std::string* from, std::string* to) const;
540
541 // Return the size of the GOT section.
542 section_size_type
543 got_size() const
544 {
545 gold_assert(this->got_ != NULL);
546 return this->got_->data_size();
547 }
548
549 // Return the number of entries in the GOT.
550 unsigned int
551 got_entry_count() const
552 {
553 if (this->got_ == NULL)
554 return 0;
555 return this->got_size() / 8;
556 }
557
558 // Return the number of entries in the PLT.
559 unsigned int
560 plt_entry_count() const;
561
562 // Return the offset of the first non-reserved PLT entry.
563 unsigned int
564 first_plt_entry_offset() const;
565
566 // Return the size of each PLT entry.
567 unsigned int
568 plt_entry_size() const;
569
570 // Create the GOT section for an incremental update.
571 Output_data_got_base*
572 init_got_plt_for_update(Symbol_table* symtab,
573 Layout* layout,
574 unsigned int got_count,
575 unsigned int plt_count);
576
577 // Reserve a GOT entry for a local symbol, and regenerate any
578 // necessary dynamic relocations.
579 void
580 reserve_local_got_entry(unsigned int got_index,
581 Sized_relobj<size, false>* obj,
582 unsigned int r_sym,
583 unsigned int got_type);
584
585 // Reserve a GOT entry for a global symbol, and regenerate any
586 // necessary dynamic relocations.
587 void
588 reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
589 unsigned int got_type);
590
591 // Register an existing PLT entry for a global symbol.
592 void
593 register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index,
594 Symbol* gsym);
595
596 // Force a COPY relocation for a given symbol.
597 void
598 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t);
599
600 // Apply an incremental relocation.
601 void
602 apply_relocation(const Relocate_info<size, false>* relinfo,
603 typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
604 unsigned int r_type,
605 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
606 const Symbol* gsym,
607 unsigned char* view,
608 typename elfcpp::Elf_types<size>::Elf_Addr address,
609 section_size_type view_size);
610
611 // Add a new reloc argument, returning the index in the vector.
612 size_t
613 add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym)
614 {
615 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
616 return this->tlsdesc_reloc_info_.size() - 1;
617 }
618
619 Output_data_plt_x86_64<size>*
620 make_data_plt(Layout* layout,
621 Output_data_got<64, false>* got,
622 Output_data_space* got_plt,
623 Output_data_space* got_irelative)
624 {
625 return this->do_make_data_plt(layout, got, got_plt, got_irelative);
626 }
627
628 Output_data_plt_x86_64<size>*
629 make_data_plt(Layout* layout,
630 Output_data_got<64, false>* got,
631 Output_data_space* got_plt,
632 Output_data_space* got_irelative,
633 unsigned int plt_count)
634 {
635 return this->do_make_data_plt(layout, got, got_plt, got_irelative,
636 plt_count);
637 }
638
639 virtual Output_data_plt_x86_64<size>*
640 do_make_data_plt(Layout* layout,
641 Output_data_got<64, false>* got,
642 Output_data_space* got_plt,
643 Output_data_space* got_irelative)
644 {
645 return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt,
646 got_irelative);
647 }
648
649 virtual Output_data_plt_x86_64<size>*
650 do_make_data_plt(Layout* layout,
651 Output_data_got<64, false>* got,
652 Output_data_space* got_plt,
653 Output_data_space* got_irelative,
654 unsigned int plt_count)
655 {
656 return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt,
657 got_irelative,
658 plt_count);
659 }
660
661 private:
662 // The class which scans relocations.
663 class Scan
664 {
665 public:
666 Scan()
667 : issued_non_pic_error_(false)
668 { }
669
670 static inline int
671 get_reference_flags(unsigned int r_type);
672
673 inline void
674 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
675 Sized_relobj_file<size, false>* object,
676 unsigned int data_shndx,
677 Output_section* output_section,
678 const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
679 const elfcpp::Sym<size, false>& lsym,
680 bool is_discarded);
681
682 inline void
683 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
684 Sized_relobj_file<size, false>* object,
685 unsigned int data_shndx,
686 Output_section* output_section,
687 const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
688 Symbol* gsym);
689
690 inline bool
691 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
692 Target_x86_64* target,
693 Sized_relobj_file<size, false>* object,
694 unsigned int data_shndx,
695 Output_section* output_section,
696 const elfcpp::Rela<size, false>& reloc,
697 unsigned int r_type,
698 const elfcpp::Sym<size, false>& lsym);
699
700 inline bool
701 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
702 Target_x86_64* target,
703 Sized_relobj_file<size, false>* object,
704 unsigned int data_shndx,
705 Output_section* output_section,
706 const elfcpp::Rela<size, false>& reloc,
707 unsigned int r_type,
708 Symbol* gsym);
709
710 private:
711 static void
712 unsupported_reloc_local(Sized_relobj_file<size, false>*,
713 unsigned int r_type);
714
715 static void
716 unsupported_reloc_global(Sized_relobj_file<size, false>*,
717 unsigned int r_type, Symbol*);
718
719 void
720 check_non_pic(Relobj*, unsigned int r_type, Symbol*);
721
722 inline bool
723 possible_function_pointer_reloc(unsigned int r_type);
724
725 bool
726 reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*,
727 unsigned int r_type);
728
729 // Whether we have issued an error about a non-PIC compilation.
730 bool issued_non_pic_error_;
731 };
732
733 // The class which implements relocation.
734 class Relocate
735 {
736 public:
737 Relocate()
738 : skip_call_tls_get_addr_(false)
739 { }
740
741 ~Relocate()
742 {
743 if (this->skip_call_tls_get_addr_)
744 {
745 // FIXME: This needs to specify the location somehow.
746 gold_error(_("missing expected TLS relocation"));
747 }
748 }
749
750 // Do a relocation. Return false if the caller should not issue
751 // any warnings about this relocation.
752 inline bool
753 relocate(const Relocate_info<size, false>*, Target_x86_64*,
754 Output_section*,
755 size_t relnum, const elfcpp::Rela<size, false>&,
756 unsigned int r_type, const Sized_symbol<size>*,
757 const Symbol_value<size>*,
758 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
759 section_size_type);
760
761 private:
762 // Do a TLS relocation.
763 inline void
764 relocate_tls(const Relocate_info<size, false>*, Target_x86_64*,
765 size_t relnum, const elfcpp::Rela<size, false>&,
766 unsigned int r_type, const Sized_symbol<size>*,
767 const Symbol_value<size>*,
768 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
769 section_size_type);
770
771 // Do a TLS General-Dynamic to Initial-Exec transition.
772 inline void
773 tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
774 Output_segment* tls_segment,
775 const elfcpp::Rela<size, false>&, unsigned int r_type,
776 typename elfcpp::Elf_types<size>::Elf_Addr value,
777 unsigned char* view,
778 typename elfcpp::Elf_types<size>::Elf_Addr,
779 section_size_type view_size);
780
781 // Do a TLS General-Dynamic to Local-Exec transition.
782 inline void
783 tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
784 Output_segment* tls_segment,
785 const elfcpp::Rela<size, false>&, unsigned int r_type,
786 typename elfcpp::Elf_types<size>::Elf_Addr value,
787 unsigned char* view,
788 section_size_type view_size);
789
790 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
791 inline void
792 tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
793 Output_segment* tls_segment,
794 const elfcpp::Rela<size, false>&, unsigned int r_type,
795 typename elfcpp::Elf_types<size>::Elf_Addr value,
796 unsigned char* view,
797 typename elfcpp::Elf_types<size>::Elf_Addr,
798 section_size_type view_size);
799
800 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
801 inline void
802 tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
803 Output_segment* tls_segment,
804 const elfcpp::Rela<size, false>&, unsigned int r_type,
805 typename elfcpp::Elf_types<size>::Elf_Addr value,
806 unsigned char* view,
807 section_size_type view_size);
808
809 // Do a TLS Local-Dynamic to Local-Exec transition.
810 inline void
811 tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum,
812 Output_segment* tls_segment,
813 const elfcpp::Rela<size, false>&, unsigned int r_type,
814 typename elfcpp::Elf_types<size>::Elf_Addr value,
815 unsigned char* view,
816 section_size_type view_size);
817
818 // Do a TLS Initial-Exec to Local-Exec transition.
819 static inline void
820 tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum,
821 Output_segment* tls_segment,
822 const elfcpp::Rela<size, false>&, unsigned int r_type,
823 typename elfcpp::Elf_types<size>::Elf_Addr value,
824 unsigned char* view,
825 section_size_type view_size);
826
827 // This is set if we should skip the next reloc, which should be a
828 // PLT32 reloc against ___tls_get_addr.
829 bool skip_call_tls_get_addr_;
830 };
831
832 // A class which returns the size required for a relocation type,
833 // used while scanning relocs during a relocatable link.
834 class Relocatable_size_for_reloc
835 {
836 public:
837 unsigned int
838 get_size_for_reloc(unsigned int, Relobj*);
839 };
840
841 // Adjust TLS relocation type based on the options and whether this
842 // is a local symbol.
843 static tls::Tls_optimization
844 optimize_tls_reloc(bool is_final, int r_type);
845
846 // Get the GOT section, creating it if necessary.
847 Output_data_got<64, false>*
848 got_section(Symbol_table*, Layout*);
849
850 // Get the GOT PLT section.
851 Output_data_space*
852 got_plt_section() const
853 {
854 gold_assert(this->got_plt_ != NULL);
855 return this->got_plt_;
856 }
857
858 // Get the GOT section for TLSDESC entries.
859 Output_data_got<64, false>*
860 got_tlsdesc_section() const
861 {
862 gold_assert(this->got_tlsdesc_ != NULL);
863 return this->got_tlsdesc_;
864 }
865
866 // Create the PLT section.
867 void
868 make_plt_section(Symbol_table* symtab, Layout* layout);
869
870 // Create a PLT entry for a global symbol.
871 void
872 make_plt_entry(Symbol_table*, Layout*, Symbol*);
873
874 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
875 void
876 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
877 Sized_relobj_file<size, false>* relobj,
878 unsigned int local_sym_index);
879
880 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
881 void
882 define_tls_base_symbol(Symbol_table*, Layout*);
883
884 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
885 void
886 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
887
888 // Create a GOT entry for the TLS module index.
889 unsigned int
890 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
891 Sized_relobj_file<size, false>* object);
892
893 // Get the PLT section.
894 Output_data_plt_x86_64<size>*
895 plt_section() const
896 {
897 gold_assert(this->plt_ != NULL);
898 return this->plt_;
899 }
900
901 // Get the dynamic reloc section, creating it if necessary.
902 Reloc_section*
903 rela_dyn_section(Layout*);
904
905 // Get the section to use for TLSDESC relocations.
906 Reloc_section*
907 rela_tlsdesc_section(Layout*) const;
908
909 // Get the section to use for IRELATIVE relocations.
910 Reloc_section*
911 rela_irelative_section(Layout*);
912
913 // Add a potential copy relocation.
914 void
915 copy_reloc(Symbol_table* symtab, Layout* layout,
916 Sized_relobj_file<size, false>* object,
917 unsigned int shndx, Output_section* output_section,
918 Symbol* sym, const elfcpp::Rela<size, false>& reloc)
919 {
920 this->copy_relocs_.copy_reloc(symtab, layout,
921 symtab->get_sized_symbol<size>(sym),
922 object, shndx, output_section,
923 reloc, this->rela_dyn_section(layout));
924 }
925
926 // Information about this specific target which we pass to the
927 // general Target structure.
928 static const Target::Target_info x86_64_info;
929
930 // The types of GOT entries needed for this platform.
931 // These values are exposed to the ABI in an incremental link.
932 // Do not renumber existing values without changing the version
933 // number of the .gnu_incremental_inputs section.
934 enum Got_type
935 {
936 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
937 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset
938 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
939 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
940 };
941
942 // This type is used as the argument to the target specific
943 // relocation routines. The only target specific reloc is
944 // R_X86_64_TLSDESC against a local symbol.
945 struct Tlsdesc_info
946 {
947 Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym)
948 : object(a_object), r_sym(a_r_sym)
949 { }
950
951 // The object in which the local symbol is defined.
952 Sized_relobj_file<size, false>* object;
953 // The local symbol index in the object.
954 unsigned int r_sym;
955 };
956
957 // The GOT section.
958 Output_data_got<64, false>* got_;
959 // The PLT section.
960 Output_data_plt_x86_64<size>* plt_;
961 // The GOT PLT section.
962 Output_data_space* got_plt_;
963 // The GOT section for IRELATIVE relocations.
964 Output_data_space* got_irelative_;
965 // The GOT section for TLSDESC relocations.
966 Output_data_got<64, false>* got_tlsdesc_;
967 // The _GLOBAL_OFFSET_TABLE_ symbol.
968 Symbol* global_offset_table_;
969 // The dynamic reloc section.
970 Reloc_section* rela_dyn_;
971 // The section to use for IRELATIVE relocs.
972 Reloc_section* rela_irelative_;
973 // Relocs saved to avoid a COPY reloc.
974 Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_;
975 // Offset of the GOT entry for the TLS module index.
976 unsigned int got_mod_index_offset_;
977 // We handle R_X86_64_TLSDESC against a local symbol as a target
978 // specific relocation. Here we store the object and local symbol
979 // index for the relocation.
980 std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
981 // True if the _TLS_MODULE_BASE_ symbol has been defined.
982 bool tls_base_symbol_defined_;
983 };
984
985 template<>
986 const Target::Target_info Target_x86_64<64>::x86_64_info =
987 {
988 64, // size
989 false, // is_big_endian
990 elfcpp::EM_X86_64, // machine_code
991 false, // has_make_symbol
992 false, // has_resolve
993 true, // has_code_fill
994 true, // is_default_stack_executable
995 true, // can_icf_inline_merge_sections
996 '\0', // wrap_char
997 "/lib/ld64.so.1", // program interpreter
998 0x400000, // default_text_segment_address
999 0x1000, // abi_pagesize (overridable by -z max-page-size)
1000 0x1000, // common_pagesize (overridable by -z common-page-size)
1001 false, // isolate_execinstr
1002 0, // rosegment_gap
1003 elfcpp::SHN_UNDEF, // small_common_shndx
1004 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
1005 0, // small_common_section_flags
1006 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
1007 NULL, // attributes_section
1008 NULL, // attributes_vendor
1009 "_start" // entry_symbol_name
1010 };
1011
1012 template<>
1013 const Target::Target_info Target_x86_64<32>::x86_64_info =
1014 {
1015 32, // size
1016 false, // is_big_endian
1017 elfcpp::EM_X86_64, // machine_code
1018 false, // has_make_symbol
1019 false, // has_resolve
1020 true, // has_code_fill
1021 true, // is_default_stack_executable
1022 true, // can_icf_inline_merge_sections
1023 '\0', // wrap_char
1024 "/libx32/ldx32.so.1", // program interpreter
1025 0x400000, // default_text_segment_address
1026 0x1000, // abi_pagesize (overridable by -z max-page-size)
1027 0x1000, // common_pagesize (overridable by -z common-page-size)
1028 false, // isolate_execinstr
1029 0, // rosegment_gap
1030 elfcpp::SHN_UNDEF, // small_common_shndx
1031 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
1032 0, // small_common_section_flags
1033 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
1034 NULL, // attributes_section
1035 NULL, // attributes_vendor
1036 "_start" // entry_symbol_name
1037 };
1038
1039 // This is called when a new output section is created. This is where
1040 // we handle the SHF_X86_64_LARGE.
1041
1042 template<int size>
1043 void
1044 Target_x86_64<size>::do_new_output_section(Output_section* os) const
1045 {
1046 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
1047 os->set_is_large_section();
1048 }
1049
1050 // Get the GOT section, creating it if necessary.
1051
1052 template<int size>
1053 Output_data_got<64, false>*
1054 Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout)
1055 {
1056 if (this->got_ == NULL)
1057 {
1058 gold_assert(symtab != NULL && layout != NULL);
1059
1060 // When using -z now, we can treat .got.plt as a relro section.
1061 // Without -z now, it is modified after program startup by lazy
1062 // PLT relocations.
1063 bool is_got_plt_relro = parameters->options().now();
1064 Output_section_order got_order = (is_got_plt_relro
1065 ? ORDER_RELRO
1066 : ORDER_RELRO_LAST);
1067 Output_section_order got_plt_order = (is_got_plt_relro
1068 ? ORDER_RELRO
1069 : ORDER_NON_RELRO_FIRST);
1070
1071 this->got_ = new Output_data_got<64, false>();
1072
1073 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
1074 (elfcpp::SHF_ALLOC
1075 | elfcpp::SHF_WRITE),
1076 this->got_, got_order, true);
1077
1078 this->got_plt_ = new Output_data_space(8, "** GOT PLT");
1079 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1080 (elfcpp::SHF_ALLOC
1081 | elfcpp::SHF_WRITE),
1082 this->got_plt_, got_plt_order,
1083 is_got_plt_relro);
1084
1085 // The first three entries are reserved.
1086 this->got_plt_->set_current_data_size(3 * 8);
1087
1088 if (!is_got_plt_relro)
1089 {
1090 // Those bytes can go into the relro segment.
1091 layout->increase_relro(3 * 8);
1092 }
1093
1094 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
1095 this->global_offset_table_ =
1096 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
1097 Symbol_table::PREDEFINED,
1098 this->got_plt_,
1099 0, 0, elfcpp::STT_OBJECT,
1100 elfcpp::STB_LOCAL,
1101 elfcpp::STV_HIDDEN, 0,
1102 false, false);
1103
1104 // If there are any IRELATIVE relocations, they get GOT entries
1105 // in .got.plt after the jump slot entries.
1106 this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT");
1107 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1108 (elfcpp::SHF_ALLOC
1109 | elfcpp::SHF_WRITE),
1110 this->got_irelative_,
1111 got_plt_order, is_got_plt_relro);
1112
1113 // If there are any TLSDESC relocations, they get GOT entries in
1114 // .got.plt after the jump slot and IRELATIVE entries.
1115 this->got_tlsdesc_ = new Output_data_got<64, false>();
1116 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1117 (elfcpp::SHF_ALLOC
1118 | elfcpp::SHF_WRITE),
1119 this->got_tlsdesc_,
1120 got_plt_order, is_got_plt_relro);
1121 }
1122
1123 return this->got_;
1124 }
1125
1126 // Get the dynamic reloc section, creating it if necessary.
1127
1128 template<int size>
1129 typename Target_x86_64<size>::Reloc_section*
1130 Target_x86_64<size>::rela_dyn_section(Layout* layout)
1131 {
1132 if (this->rela_dyn_ == NULL)
1133 {
1134 gold_assert(layout != NULL);
1135 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
1136 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
1137 elfcpp::SHF_ALLOC, this->rela_dyn_,
1138 ORDER_DYNAMIC_RELOCS, false);
1139 }
1140 return this->rela_dyn_;
1141 }
1142
1143 // Get the section to use for IRELATIVE relocs, creating it if
1144 // necessary. These go in .rela.dyn, but only after all other dynamic
1145 // relocations. They need to follow the other dynamic relocations so
1146 // that they can refer to global variables initialized by those
1147 // relocs.
1148
1149 template<int size>
1150 typename Target_x86_64<size>::Reloc_section*
1151 Target_x86_64<size>::rela_irelative_section(Layout* layout)
1152 {
1153 if (this->rela_irelative_ == NULL)
1154 {
1155 // Make sure we have already created the dynamic reloc section.
1156 this->rela_dyn_section(layout);
1157 this->rela_irelative_ = new Reloc_section(false);
1158 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
1159 elfcpp::SHF_ALLOC, this->rela_irelative_,
1160 ORDER_DYNAMIC_RELOCS, false);
1161 gold_assert(this->rela_dyn_->output_section()
1162 == this->rela_irelative_->output_section());
1163 }
1164 return this->rela_irelative_;
1165 }
1166
1167 // Initialize the PLT section.
1168
1169 template<int size>
1170 void
1171 Output_data_plt_x86_64<size>::init(Layout* layout)
1172 {
1173 this->rel_ = new Reloc_section(false);
1174 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1175 elfcpp::SHF_ALLOC, this->rel_,
1176 ORDER_DYNAMIC_PLT_RELOCS, false);
1177 }
1178
1179 template<int size>
1180 void
1181 Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os)
1182 {
1183 os->set_entsize(this->get_plt_entry_size());
1184 }
1185
1186 // Add an entry to the PLT.
1187
1188 template<int size>
1189 void
1190 Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout,
1191 Symbol* gsym)
1192 {
1193 gold_assert(!gsym->has_plt_offset());
1194
1195 unsigned int plt_index;
1196 off_t plt_offset;
1197 section_offset_type got_offset;
1198
1199 unsigned int* pcount;
1200 unsigned int offset;
1201 unsigned int reserved;
1202 Output_data_space* got;
1203 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1204 && gsym->can_use_relative_reloc(false))
1205 {
1206 pcount = &this->irelative_count_;
1207 offset = 0;
1208 reserved = 0;
1209 got = this->got_irelative_;
1210 }
1211 else
1212 {
1213 pcount = &this->count_;
1214 offset = 1;
1215 reserved = 3;
1216 got = this->got_plt_;
1217 }
1218
1219 if (!this->is_data_size_valid())
1220 {
1221 // Note that when setting the PLT offset for a non-IRELATIVE
1222 // entry we skip the initial reserved PLT entry.
1223 plt_index = *pcount + offset;
1224 plt_offset = plt_index * this->get_plt_entry_size();
1225
1226 ++*pcount;
1227
1228 got_offset = (plt_index - offset + reserved) * 8;
1229 gold_assert(got_offset == got->current_data_size());
1230
1231 // Every PLT entry needs a GOT entry which points back to the PLT
1232 // entry (this will be changed by the dynamic linker, normally
1233 // lazily when the function is called).
1234 got->set_current_data_size(got_offset + 8);
1235 }
1236 else
1237 {
1238 // FIXME: This is probably not correct for IRELATIVE relocs.
1239
1240 // For incremental updates, find an available slot.
1241 plt_offset = this->free_list_.allocate(this->get_plt_entry_size(),
1242 this->get_plt_entry_size(), 0);
1243 if (plt_offset == -1)
1244 gold_fallback(_("out of patch space (PLT);"
1245 " relink with --incremental-full"));
1246
1247 // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset
1248 // can be calculated from the PLT index, adjusting for the three
1249 // reserved entries at the beginning of the GOT.
1250 plt_index = plt_offset / this->get_plt_entry_size() - 1;
1251 got_offset = (plt_index - offset + reserved) * 8;
1252 }
1253
1254 gsym->set_plt_offset(plt_offset);
1255
1256 // Every PLT entry needs a reloc.
1257 this->add_relocation(symtab, layout, gsym, got_offset);
1258
1259 // Note that we don't need to save the symbol. The contents of the
1260 // PLT are independent of which symbols are used. The symbols only
1261 // appear in the relocations.
1262 }
1263
1264 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1265 // the PLT offset.
1266
1267 template<int size>
1268 unsigned int
1269 Output_data_plt_x86_64<size>::add_local_ifunc_entry(
1270 Symbol_table* symtab,
1271 Layout* layout,
1272 Sized_relobj_file<size, false>* relobj,
1273 unsigned int local_sym_index)
1274 {
1275 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1276 ++this->irelative_count_;
1277
1278 section_offset_type got_offset = this->got_irelative_->current_data_size();
1279
1280 // Every PLT entry needs a GOT entry which points back to the PLT
1281 // entry.
1282 this->got_irelative_->set_current_data_size(got_offset + 8);
1283
1284 // Every PLT entry needs a reloc.
1285 Reloc_section* rela = this->rela_irelative(symtab, layout);
1286 rela->add_symbolless_local_addend(relobj, local_sym_index,
1287 elfcpp::R_X86_64_IRELATIVE,
1288 this->got_irelative_, got_offset, 0);
1289
1290 return plt_offset;
1291 }
1292
1293 // Add the relocation for a PLT entry.
1294
1295 template<int size>
1296 void
1297 Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab,
1298 Layout* layout,
1299 Symbol* gsym,
1300 unsigned int got_offset)
1301 {
1302 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1303 && gsym->can_use_relative_reloc(false))
1304 {
1305 Reloc_section* rela = this->rela_irelative(symtab, layout);
1306 rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
1307 this->got_irelative_, got_offset, 0);
1308 }
1309 else
1310 {
1311 gsym->set_needs_dynsym_entry();
1312 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
1313 got_offset, 0);
1314 }
1315 }
1316
1317 // Return where the TLSDESC relocations should go, creating it if
1318 // necessary. These follow the JUMP_SLOT relocations.
1319
1320 template<int size>
1321 typename Output_data_plt_x86_64<size>::Reloc_section*
1322 Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout)
1323 {
1324 if (this->tlsdesc_rel_ == NULL)
1325 {
1326 this->tlsdesc_rel_ = new Reloc_section(false);
1327 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1328 elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
1329 ORDER_DYNAMIC_PLT_RELOCS, false);
1330 gold_assert(this->tlsdesc_rel_->output_section()
1331 == this->rel_->output_section());
1332 }
1333 return this->tlsdesc_rel_;
1334 }
1335
1336 // Return where the IRELATIVE relocations should go in the PLT. These
1337 // follow the JUMP_SLOT and the TLSDESC relocations.
1338
1339 template<int size>
1340 typename Output_data_plt_x86_64<size>::Reloc_section*
1341 Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab,
1342 Layout* layout)
1343 {
1344 if (this->irelative_rel_ == NULL)
1345 {
1346 // Make sure we have a place for the TLSDESC relocations, in
1347 // case we see any later on.
1348 this->rela_tlsdesc(layout);
1349 this->irelative_rel_ = new Reloc_section(false);
1350 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1351 elfcpp::SHF_ALLOC, this->irelative_rel_,
1352 ORDER_DYNAMIC_PLT_RELOCS, false);
1353 gold_assert(this->irelative_rel_->output_section()
1354 == this->rel_->output_section());
1355
1356 if (parameters->doing_static_link())
1357 {
1358 // A statically linked executable will only have a .rela.plt
1359 // section to hold R_X86_64_IRELATIVE relocs for
1360 // STT_GNU_IFUNC symbols. The library will use these
1361 // symbols to locate the IRELATIVE relocs at program startup
1362 // time.
1363 symtab->define_in_output_data("__rela_iplt_start", NULL,
1364 Symbol_table::PREDEFINED,
1365 this->irelative_rel_, 0, 0,
1366 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1367 elfcpp::STV_HIDDEN, 0, false, true);
1368 symtab->define_in_output_data("__rela_iplt_end", NULL,
1369 Symbol_table::PREDEFINED,
1370 this->irelative_rel_, 0, 0,
1371 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1372 elfcpp::STV_HIDDEN, 0, true, true);
1373 }
1374 }
1375 return this->irelative_rel_;
1376 }
1377
1378 // Return the PLT address to use for a global symbol.
1379
1380 template<int size>
1381 uint64_t
1382 Output_data_plt_x86_64<size>::address_for_global(const Symbol* gsym)
1383 {
1384 uint64_t offset = 0;
1385 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1386 && gsym->can_use_relative_reloc(false))
1387 offset = (this->count_ + 1) * this->get_plt_entry_size();
1388 return this->address() + offset + gsym->plt_offset();
1389 }
1390
1391 // Return the PLT address to use for a local symbol. These are always
1392 // IRELATIVE relocs.
1393
1394 template<int size>
1395 uint64_t
1396 Output_data_plt_x86_64<size>::address_for_local(const Relobj* object,
1397 unsigned int r_sym)
1398 {
1399 return (this->address()
1400 + (this->count_ + 1) * this->get_plt_entry_size()
1401 + object->local_plt_offset(r_sym));
1402 }
1403
1404 // Set the final size.
1405 template<int size>
1406 void
1407 Output_data_plt_x86_64<size>::set_final_data_size()
1408 {
1409 unsigned int count = this->count_ + this->irelative_count_;
1410 if (this->has_tlsdesc_entry())
1411 ++count;
1412 this->set_data_size((count + 1) * this->get_plt_entry_size());
1413 }
1414
1415 // The first entry in the PLT for an executable.
1416
1417 template<int size>
1418 const unsigned char
1419 Output_data_plt_x86_64_standard<size>::first_plt_entry[plt_entry_size] =
1420 {
1421 // From AMD64 ABI Draft 0.98, page 76
1422 0xff, 0x35, // pushq contents of memory address
1423 0, 0, 0, 0, // replaced with address of .got + 8
1424 0xff, 0x25, // jmp indirect
1425 0, 0, 0, 0, // replaced with address of .got + 16
1426 0x90, 0x90, 0x90, 0x90 // noop (x4)
1427 };
1428
1429 template<int size>
1430 void
1431 Output_data_plt_x86_64_standard<size>::do_fill_first_plt_entry(
1432 unsigned char* pov,
1433 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
1434 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
1435 {
1436 memcpy(pov, first_plt_entry, plt_entry_size);
1437 // We do a jmp relative to the PC at the end of this instruction.
1438 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1439 (got_address + 8
1440 - (plt_address + 6)));
1441 elfcpp::Swap<32, false>::writeval(pov + 8,
1442 (got_address + 16
1443 - (plt_address + 12)));
1444 }
1445
1446 // Subsequent entries in the PLT for an executable.
1447
1448 template<int size>
1449 const unsigned char
1450 Output_data_plt_x86_64_standard<size>::plt_entry[plt_entry_size] =
1451 {
1452 // From AMD64 ABI Draft 0.98, page 76
1453 0xff, 0x25, // jmpq indirect
1454 0, 0, 0, 0, // replaced with address of symbol in .got
1455 0x68, // pushq immediate
1456 0, 0, 0, 0, // replaced with offset into relocation table
1457 0xe9, // jmpq relative
1458 0, 0, 0, 0 // replaced with offset to start of .plt
1459 };
1460
1461 template<int size>
1462 unsigned int
1463 Output_data_plt_x86_64_standard<size>::do_fill_plt_entry(
1464 unsigned char* pov,
1465 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
1466 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
1467 unsigned int got_offset,
1468 unsigned int plt_offset,
1469 unsigned int plt_index)
1470 {
1471 memcpy(pov, plt_entry, plt_entry_size);
1472 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1473 (got_address + got_offset
1474 - (plt_address + plt_offset
1475 + 6)));
1476
1477 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
1478 elfcpp::Swap<32, false>::writeval(pov + 12,
1479 - (plt_offset + plt_entry_size));
1480
1481 return 6;
1482 }
1483
1484 // The reserved TLSDESC entry in the PLT for an executable.
1485
1486 template<int size>
1487 const unsigned char
1488 Output_data_plt_x86_64_standard<size>::tlsdesc_plt_entry[plt_entry_size] =
1489 {
1490 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
1491 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
1492 0xff, 0x35, // pushq x(%rip)
1493 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
1494 0xff, 0x25, // jmpq *y(%rip)
1495 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
1496 0x0f, 0x1f, // nop
1497 0x40, 0
1498 };
1499
1500 template<int size>
1501 void
1502 Output_data_plt_x86_64_standard<size>::do_fill_tlsdesc_entry(
1503 unsigned char* pov,
1504 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
1505 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
1506 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
1507 unsigned int tlsdesc_got_offset,
1508 unsigned int plt_offset)
1509 {
1510 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
1511 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1512 (got_address + 8
1513 - (plt_address + plt_offset
1514 + 6)));
1515 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
1516 (got_base
1517 + tlsdesc_got_offset
1518 - (plt_address + plt_offset
1519 + 12)));
1520 }
1521
1522 // The .eh_frame unwind information for the PLT.
1523
1524 template<int size>
1525 const unsigned char
1526 Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1527 {
1528 1, // CIE version.
1529 'z', // Augmentation: augmentation size included.
1530 'R', // Augmentation: FDE encoding included.
1531 '\0', // End of augmentation string.
1532 1, // Code alignment factor.
1533 0x78, // Data alignment factor.
1534 16, // Return address column.
1535 1, // Augmentation size.
1536 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1537 | elfcpp::DW_EH_PE_sdata4),
1538 elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8.
1539 elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8.
1540 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1541 elfcpp::DW_CFA_nop
1542 };
1543
1544 template<int size>
1545 const unsigned char
1546 Output_data_plt_x86_64_standard<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1547 {
1548 0, 0, 0, 0, // Replaced with offset to .plt.
1549 0, 0, 0, 0, // Replaced with size of .plt.
1550 0, // Augmentation size.
1551 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
1552 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1553 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
1554 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1555 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1556 11, // Block length.
1557 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
1558 elfcpp::DW_OP_breg16, 0, // Push %rip.
1559 elfcpp::DW_OP_lit15, // Push 0xf.
1560 elfcpp::DW_OP_and, // & (%rip & 0xf).
1561 elfcpp::DW_OP_lit11, // Push 0xb.
1562 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb)
1563 elfcpp::DW_OP_lit3, // Push 3.
1564 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3)
1565 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8
1566 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1567 elfcpp::DW_CFA_nop,
1568 elfcpp::DW_CFA_nop,
1569 elfcpp::DW_CFA_nop
1570 };
1571
1572 // Write out the PLT. This uses the hand-coded instructions above,
1573 // and adjusts them as needed. This is specified by the AMD64 ABI.
1574
1575 template<int size>
1576 void
1577 Output_data_plt_x86_64<size>::do_write(Output_file* of)
1578 {
1579 const off_t offset = this->offset();
1580 const section_size_type oview_size =
1581 convert_to_section_size_type(this->data_size());
1582 unsigned char* const oview = of->get_output_view(offset, oview_size);
1583
1584 const off_t got_file_offset = this->got_plt_->offset();
1585 gold_assert(parameters->incremental_update()
1586 || (got_file_offset + this->got_plt_->data_size()
1587 == this->got_irelative_->offset()));
1588 const section_size_type got_size =
1589 convert_to_section_size_type(this->got_plt_->data_size()
1590 + this->got_irelative_->data_size());
1591 unsigned char* const got_view = of->get_output_view(got_file_offset,
1592 got_size);
1593
1594 unsigned char* pov = oview;
1595
1596 // The base address of the .plt section.
1597 typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address();
1598 // The base address of the .got section.
1599 typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address();
1600 // The base address of the PLT portion of the .got section,
1601 // which is where the GOT pointer will point, and where the
1602 // three reserved GOT entries are located.
1603 typename elfcpp::Elf_types<size>::Elf_Addr got_address
1604 = this->got_plt_->address();
1605
1606 this->fill_first_plt_entry(pov, got_address, plt_address);
1607 pov += this->get_plt_entry_size();
1608
1609 unsigned char* got_pov = got_view;
1610
1611 // The first entry in the GOT is the address of the .dynamic section
1612 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1613 // We saved space for them when we created the section in
1614 // Target_x86_64::got_section.
1615 Output_section* dynamic = this->layout_->dynamic_section();
1616 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1617 elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr);
1618 got_pov += 8;
1619 memset(got_pov, 0, 16);
1620 got_pov += 16;
1621
1622 unsigned int plt_offset = this->get_plt_entry_size();
1623 unsigned int got_offset = 24;
1624 const unsigned int count = this->count_ + this->irelative_count_;
1625 for (unsigned int plt_index = 0;
1626 plt_index < count;
1627 ++plt_index,
1628 pov += this->get_plt_entry_size(),
1629 got_pov += 8,
1630 plt_offset += this->get_plt_entry_size(),
1631 got_offset += 8)
1632 {
1633 // Set and adjust the PLT entry itself.
1634 unsigned int lazy_offset = this->fill_plt_entry(pov,
1635 got_address, plt_address,
1636 got_offset, plt_offset,
1637 plt_index);
1638
1639 // Set the entry in the GOT.
1640 elfcpp::Swap<64, false>::writeval(got_pov,
1641 plt_address + plt_offset + lazy_offset);
1642 }
1643
1644 if (this->has_tlsdesc_entry())
1645 {
1646 // Set and adjust the reserved TLSDESC PLT entry.
1647 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
1648 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
1649 tlsdesc_got_offset, plt_offset);
1650 pov += this->get_plt_entry_size();
1651 }
1652
1653 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1654 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1655
1656 of->write_output_view(offset, oview_size, oview);
1657 of->write_output_view(got_file_offset, got_size, got_view);
1658 }
1659
1660 // Create the PLT section.
1661
1662 template<int size>
1663 void
1664 Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout)
1665 {
1666 if (this->plt_ == NULL)
1667 {
1668 // Create the GOT sections first.
1669 this->got_section(symtab, layout);
1670
1671 this->plt_ = this->make_data_plt(layout, this->got_, this->got_plt_,
1672 this->got_irelative_);
1673
1674 // Add unwind information if requested.
1675 if (parameters->options().ld_generated_unwind_info())
1676 this->plt_->add_eh_frame(layout);
1677
1678 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1679 (elfcpp::SHF_ALLOC
1680 | elfcpp::SHF_EXECINSTR),
1681 this->plt_, ORDER_PLT, false);
1682
1683 // Make the sh_info field of .rela.plt point to .plt.
1684 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1685 rela_plt_os->set_info_section(this->plt_->output_section());
1686 }
1687 }
1688
1689 // Return the section for TLSDESC relocations.
1690
1691 template<int size>
1692 typename Target_x86_64<size>::Reloc_section*
1693 Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const
1694 {
1695 return this->plt_section()->rela_tlsdesc(layout);
1696 }
1697
1698 // Create a PLT entry for a global symbol.
1699
1700 template<int size>
1701 void
1702 Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout,
1703 Symbol* gsym)
1704 {
1705 if (gsym->has_plt_offset())
1706 return;
1707
1708 if (this->plt_ == NULL)
1709 this->make_plt_section(symtab, layout);
1710
1711 this->plt_->add_entry(symtab, layout, gsym);
1712 }
1713
1714 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1715
1716 template<int size>
1717 void
1718 Target_x86_64<size>::make_local_ifunc_plt_entry(
1719 Symbol_table* symtab, Layout* layout,
1720 Sized_relobj_file<size, false>* relobj,
1721 unsigned int local_sym_index)
1722 {
1723 if (relobj->local_has_plt_offset(local_sym_index))
1724 return;
1725 if (this->plt_ == NULL)
1726 this->make_plt_section(symtab, layout);
1727 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1728 relobj,
1729 local_sym_index);
1730 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1731 }
1732
1733 // Return the number of entries in the PLT.
1734
1735 template<int size>
1736 unsigned int
1737 Target_x86_64<size>::plt_entry_count() const
1738 {
1739 if (this->plt_ == NULL)
1740 return 0;
1741 return this->plt_->entry_count();
1742 }
1743
1744 // Return the offset of the first non-reserved PLT entry.
1745
1746 template<int size>
1747 unsigned int
1748 Target_x86_64<size>::first_plt_entry_offset() const
1749 {
1750 return this->plt_->first_plt_entry_offset();
1751 }
1752
1753 // Return the size of each PLT entry.
1754
1755 template<int size>
1756 unsigned int
1757 Target_x86_64<size>::plt_entry_size() const
1758 {
1759 return this->plt_->get_plt_entry_size();
1760 }
1761
1762 // Create the GOT and PLT sections for an incremental update.
1763
1764 template<int size>
1765 Output_data_got_base*
1766 Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab,
1767 Layout* layout,
1768 unsigned int got_count,
1769 unsigned int plt_count)
1770 {
1771 gold_assert(this->got_ == NULL);
1772
1773 this->got_ = new Output_data_got<64, false>(got_count * 8);
1774 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
1775 (elfcpp::SHF_ALLOC
1776 | elfcpp::SHF_WRITE),
1777 this->got_, ORDER_RELRO_LAST,
1778 true);
1779
1780 // Add the three reserved entries.
1781 this->got_plt_ = new Output_data_space((plt_count + 3) * 8, 8, "** GOT PLT");
1782 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1783 (elfcpp::SHF_ALLOC
1784 | elfcpp::SHF_WRITE),
1785 this->got_plt_, ORDER_NON_RELRO_FIRST,
1786 false);
1787
1788 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
1789 this->global_offset_table_ =
1790 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
1791 Symbol_table::PREDEFINED,
1792 this->got_plt_,
1793 0, 0, elfcpp::STT_OBJECT,
1794 elfcpp::STB_LOCAL,
1795 elfcpp::STV_HIDDEN, 0,
1796 false, false);
1797
1798 // If there are any TLSDESC relocations, they get GOT entries in
1799 // .got.plt after the jump slot entries.
1800 // FIXME: Get the count for TLSDESC entries.
1801 this->got_tlsdesc_ = new Output_data_got<64, false>(0);
1802 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1803 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1804 this->got_tlsdesc_,
1805 ORDER_NON_RELRO_FIRST, false);
1806
1807 // If there are any IRELATIVE relocations, they get GOT entries in
1808 // .got.plt after the jump slot and TLSDESC entries.
1809 this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT");
1810 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1811 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1812 this->got_irelative_,
1813 ORDER_NON_RELRO_FIRST, false);
1814
1815 // Create the PLT section.
1816 this->plt_ = this->make_data_plt(layout, this->got_,
1817 this->got_plt_,
1818 this->got_irelative_,
1819 plt_count);
1820
1821 // Add unwind information if requested.
1822 if (parameters->options().ld_generated_unwind_info())
1823 this->plt_->add_eh_frame(layout);
1824
1825 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1826 elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR,
1827 this->plt_, ORDER_PLT, false);
1828
1829 // Make the sh_info field of .rela.plt point to .plt.
1830 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1831 rela_plt_os->set_info_section(this->plt_->output_section());
1832
1833 // Create the rela_dyn section.
1834 this->rela_dyn_section(layout);
1835
1836 return this->got_;
1837 }
1838
1839 // Reserve a GOT entry for a local symbol, and regenerate any
1840 // necessary dynamic relocations.
1841
1842 template<int size>
1843 void
1844 Target_x86_64<size>::reserve_local_got_entry(
1845 unsigned int got_index,
1846 Sized_relobj<size, false>* obj,
1847 unsigned int r_sym,
1848 unsigned int got_type)
1849 {
1850 unsigned int got_offset = got_index * 8;
1851 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1852
1853 this->got_->reserve_local(got_index, obj, r_sym, got_type);
1854 switch (got_type)
1855 {
1856 case GOT_TYPE_STANDARD:
1857 if (parameters->options().output_is_position_independent())
1858 rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
1859 this->got_, got_offset, 0, false);
1860 break;
1861 case GOT_TYPE_TLS_OFFSET:
1862 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
1863 this->got_, got_offset, 0);
1864 break;
1865 case GOT_TYPE_TLS_PAIR:
1866 this->got_->reserve_slot(got_index + 1);
1867 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64,
1868 this->got_, got_offset, 0);
1869 break;
1870 case GOT_TYPE_TLS_DESC:
1871 gold_fatal(_("TLS_DESC not yet supported for incremental linking"));
1872 // this->got_->reserve_slot(got_index + 1);
1873 // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1874 // this->got_, got_offset, 0);
1875 break;
1876 default:
1877 gold_unreachable();
1878 }
1879 }
1880
1881 // Reserve a GOT entry for a global symbol, and regenerate any
1882 // necessary dynamic relocations.
1883
1884 template<int size>
1885 void
1886 Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index,
1887 Symbol* gsym,
1888 unsigned int got_type)
1889 {
1890 unsigned int got_offset = got_index * 8;
1891 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1892
1893 this->got_->reserve_global(got_index, gsym, got_type);
1894 switch (got_type)
1895 {
1896 case GOT_TYPE_STANDARD:
1897 if (!gsym->final_value_is_known())
1898 {
1899 if (gsym->is_from_dynobj()
1900 || gsym->is_undefined()
1901 || gsym->is_preemptible()
1902 || gsym->type() == elfcpp::STT_GNU_IFUNC)
1903 rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT,
1904 this->got_, got_offset, 0);
1905 else
1906 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1907 this->got_, got_offset, 0, false);
1908 }
1909 break;
1910 case GOT_TYPE_TLS_OFFSET:
1911 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64,
1912 this->got_, got_offset, 0, false);
1913 break;
1914 case GOT_TYPE_TLS_PAIR:
1915 this->got_->reserve_slot(got_index + 1);
1916 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64,
1917 this->got_, got_offset, 0, false);
1918 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64,
1919 this->got_, got_offset + 8, 0, false);
1920 break;
1921 case GOT_TYPE_TLS_DESC:
1922 this->got_->reserve_slot(got_index + 1);
1923 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC,
1924 this->got_, got_offset, 0, false);
1925 break;
1926 default:
1927 gold_unreachable();
1928 }
1929 }
1930
1931 // Register an existing PLT entry for a global symbol.
1932
1933 template<int size>
1934 void
1935 Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab,
1936 Layout* layout,
1937 unsigned int plt_index,
1938 Symbol* gsym)
1939 {
1940 gold_assert(this->plt_ != NULL);
1941 gold_assert(!gsym->has_plt_offset());
1942
1943 this->plt_->reserve_slot(plt_index);
1944
1945 gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
1946
1947 unsigned int got_offset = (plt_index + 3) * 8;
1948 this->plt_->add_relocation(symtab, layout, gsym, got_offset);
1949 }
1950
1951 // Force a COPY relocation for a given symbol.
1952
1953 template<int size>
1954 void
1955 Target_x86_64<size>::emit_copy_reloc(
1956 Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset)
1957 {
1958 this->copy_relocs_.emit_copy_reloc(symtab,
1959 symtab->get_sized_symbol<size>(sym),
1960 os,
1961 offset,
1962 this->rela_dyn_section(NULL));
1963 }
1964
1965 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1966
1967 template<int size>
1968 void
1969 Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab,
1970 Layout* layout)
1971 {
1972 if (this->tls_base_symbol_defined_)
1973 return;
1974
1975 Output_segment* tls_segment = layout->tls_segment();
1976 if (tls_segment != NULL)
1977 {
1978 bool is_exec = parameters->options().output_is_executable();
1979 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1980 Symbol_table::PREDEFINED,
1981 tls_segment, 0, 0,
1982 elfcpp::STT_TLS,
1983 elfcpp::STB_LOCAL,
1984 elfcpp::STV_HIDDEN, 0,
1985 (is_exec
1986 ? Symbol::SEGMENT_END
1987 : Symbol::SEGMENT_START),
1988 true);
1989 }
1990 this->tls_base_symbol_defined_ = true;
1991 }
1992
1993 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1994
1995 template<int size>
1996 void
1997 Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab,
1998 Layout* layout)
1999 {
2000 if (this->plt_ == NULL)
2001 this->make_plt_section(symtab, layout);
2002
2003 if (!this->plt_->has_tlsdesc_entry())
2004 {
2005 // Allocate the TLSDESC_GOT entry.
2006 Output_data_got<64, false>* got = this->got_section(symtab, layout);
2007 unsigned int got_offset = got->add_constant(0);
2008
2009 // Allocate the TLSDESC_PLT entry.
2010 this->plt_->reserve_tlsdesc_entry(got_offset);
2011 }
2012 }
2013
2014 // Create a GOT entry for the TLS module index.
2015
2016 template<int size>
2017 unsigned int
2018 Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
2019 Sized_relobj_file<size, false>* object)
2020 {
2021 if (this->got_mod_index_offset_ == -1U)
2022 {
2023 gold_assert(symtab != NULL && layout != NULL && object != NULL);
2024 Reloc_section* rela_dyn = this->rela_dyn_section(layout);
2025 Output_data_got<64, false>* got = this->got_section(symtab, layout);
2026 unsigned int got_offset = got->add_constant(0);
2027 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
2028 got_offset, 0);
2029 got->add_constant(0);
2030 this->got_mod_index_offset_ = got_offset;
2031 }
2032 return this->got_mod_index_offset_;
2033 }
2034
2035 // Optimize the TLS relocation type based on what we know about the
2036 // symbol. IS_FINAL is true if the final address of this symbol is
2037 // known at link time.
2038
2039 template<int size>
2040 tls::Tls_optimization
2041 Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type)
2042 {
2043 // If we are generating a shared library, then we can't do anything
2044 // in the linker.
2045 if (parameters->options().shared())
2046 return tls::TLSOPT_NONE;
2047
2048 switch (r_type)
2049 {
2050 case elfcpp::R_X86_64_TLSGD:
2051 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2052 case elfcpp::R_X86_64_TLSDESC_CALL:
2053 // These are General-Dynamic which permits fully general TLS
2054 // access. Since we know that we are generating an executable,
2055 // we can convert this to Initial-Exec. If we also know that
2056 // this is a local symbol, we can further switch to Local-Exec.
2057 if (is_final)
2058 return tls::TLSOPT_TO_LE;
2059 return tls::TLSOPT_TO_IE;
2060
2061 case elfcpp::R_X86_64_TLSLD:
2062 // This is Local-Dynamic, which refers to a local symbol in the
2063 // dynamic TLS block. Since we know that we generating an
2064 // executable, we can switch to Local-Exec.
2065 return tls::TLSOPT_TO_LE;
2066
2067 case elfcpp::R_X86_64_DTPOFF32:
2068 case elfcpp::R_X86_64_DTPOFF64:
2069 // Another Local-Dynamic reloc.
2070 return tls::TLSOPT_TO_LE;
2071
2072 case elfcpp::R_X86_64_GOTTPOFF:
2073 // These are Initial-Exec relocs which get the thread offset
2074 // from the GOT. If we know that we are linking against the
2075 // local symbol, we can switch to Local-Exec, which links the
2076 // thread offset into the instruction.
2077 if (is_final)
2078 return tls::TLSOPT_TO_LE;
2079 return tls::TLSOPT_NONE;
2080
2081 case elfcpp::R_X86_64_TPOFF32:
2082 // When we already have Local-Exec, there is nothing further we
2083 // can do.
2084 return tls::TLSOPT_NONE;
2085
2086 default:
2087 gold_unreachable();
2088 }
2089 }
2090
2091 // Get the Reference_flags for a particular relocation.
2092
2093 template<int size>
2094 int
2095 Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type)
2096 {
2097 switch (r_type)
2098 {
2099 case elfcpp::R_X86_64_NONE:
2100 case elfcpp::R_X86_64_GNU_VTINHERIT:
2101 case elfcpp::R_X86_64_GNU_VTENTRY:
2102 case elfcpp::R_X86_64_GOTPC32:
2103 case elfcpp::R_X86_64_GOTPC64:
2104 // No symbol reference.
2105 return 0;
2106
2107 case elfcpp::R_X86_64_64:
2108 case elfcpp::R_X86_64_32:
2109 case elfcpp::R_X86_64_32S:
2110 case elfcpp::R_X86_64_16:
2111 case elfcpp::R_X86_64_8:
2112 return Symbol::ABSOLUTE_REF;
2113
2114 case elfcpp::R_X86_64_PC64:
2115 case elfcpp::R_X86_64_PC32:
2116 case elfcpp::R_X86_64_PC16:
2117 case elfcpp::R_X86_64_PC8:
2118 case elfcpp::R_X86_64_GOTOFF64:
2119 return Symbol::RELATIVE_REF;
2120
2121 case elfcpp::R_X86_64_PLT32:
2122 case elfcpp::R_X86_64_PLTOFF64:
2123 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
2124
2125 case elfcpp::R_X86_64_GOT64:
2126 case elfcpp::R_X86_64_GOT32:
2127 case elfcpp::R_X86_64_GOTPCREL64:
2128 case elfcpp::R_X86_64_GOTPCREL:
2129 case elfcpp::R_X86_64_GOTPLT64:
2130 // Absolute in GOT.
2131 return Symbol::ABSOLUTE_REF;
2132
2133 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2134 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2135 case elfcpp::R_X86_64_TLSDESC_CALL:
2136 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2137 case elfcpp::R_X86_64_DTPOFF32:
2138 case elfcpp::R_X86_64_DTPOFF64:
2139 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2140 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2141 return Symbol::TLS_REF;
2142
2143 case elfcpp::R_X86_64_COPY:
2144 case elfcpp::R_X86_64_GLOB_DAT:
2145 case elfcpp::R_X86_64_JUMP_SLOT:
2146 case elfcpp::R_X86_64_RELATIVE:
2147 case elfcpp::R_X86_64_IRELATIVE:
2148 case elfcpp::R_X86_64_TPOFF64:
2149 case elfcpp::R_X86_64_DTPMOD64:
2150 case elfcpp::R_X86_64_TLSDESC:
2151 case elfcpp::R_X86_64_SIZE32:
2152 case elfcpp::R_X86_64_SIZE64:
2153 default:
2154 // Not expected. We will give an error later.
2155 return 0;
2156 }
2157 }
2158
2159 // Report an unsupported relocation against a local symbol.
2160
2161 template<int size>
2162 void
2163 Target_x86_64<size>::Scan::unsupported_reloc_local(
2164 Sized_relobj_file<size, false>* object,
2165 unsigned int r_type)
2166 {
2167 gold_error(_("%s: unsupported reloc %u against local symbol"),
2168 object->name().c_str(), r_type);
2169 }
2170
2171 // We are about to emit a dynamic relocation of type R_TYPE. If the
2172 // dynamic linker does not support it, issue an error. The GNU linker
2173 // only issues a non-PIC error for an allocated read-only section.
2174 // Here we know the section is allocated, but we don't know that it is
2175 // read-only. But we check for all the relocation types which the
2176 // glibc dynamic linker supports, so it seems appropriate to issue an
2177 // error even if the section is not read-only. If GSYM is not NULL,
2178 // it is the symbol the relocation is against; if it is NULL, the
2179 // relocation is against a local symbol.
2180
2181 template<int size>
2182 void
2183 Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type,
2184 Symbol* gsym)
2185 {
2186 switch (r_type)
2187 {
2188 // These are the relocation types supported by glibc for x86_64
2189 // which should always work.
2190 case elfcpp::R_X86_64_RELATIVE:
2191 case elfcpp::R_X86_64_IRELATIVE:
2192 case elfcpp::R_X86_64_GLOB_DAT:
2193 case elfcpp::R_X86_64_JUMP_SLOT:
2194 case elfcpp::R_X86_64_DTPMOD64:
2195 case elfcpp::R_X86_64_DTPOFF64:
2196 case elfcpp::R_X86_64_TPOFF64:
2197 case elfcpp::R_X86_64_64:
2198 case elfcpp::R_X86_64_COPY:
2199 return;
2200
2201 // glibc supports these reloc types, but they can overflow.
2202 case elfcpp::R_X86_64_PC32:
2203 // A PC relative reference is OK against a local symbol or if
2204 // the symbol is defined locally.
2205 if (gsym == NULL
2206 || (!gsym->is_from_dynobj()
2207 && !gsym->is_undefined()
2208 && !gsym->is_preemptible()))
2209 return;
2210 /* Fall through. */
2211 case elfcpp::R_X86_64_32:
2212 // R_X86_64_32 is OK for x32.
2213 if (size == 32 && r_type == elfcpp::R_X86_64_32)
2214 return;
2215 if (this->issued_non_pic_error_)
2216 return;
2217 gold_assert(parameters->options().output_is_position_independent());
2218 if (gsym == NULL)
2219 object->error(_("requires dynamic R_X86_64_32 reloc which may "
2220 "overflow at runtime; recompile with -fPIC"));
2221 else
2222 object->error(_("requires dynamic %s reloc against '%s' which may "
2223 "overflow at runtime; recompile with -fPIC"),
2224 (r_type == elfcpp::R_X86_64_32
2225 ? "R_X86_64_32"
2226 : "R_X86_64_PC32"),
2227 gsym->name());
2228 this->issued_non_pic_error_ = true;
2229 return;
2230
2231 default:
2232 // This prevents us from issuing more than one error per reloc
2233 // section. But we can still wind up issuing more than one
2234 // error per object file.
2235 if (this->issued_non_pic_error_)
2236 return;
2237 gold_assert(parameters->options().output_is_position_independent());
2238 object->error(_("requires unsupported dynamic reloc %u; "
2239 "recompile with -fPIC"),
2240 r_type);
2241 this->issued_non_pic_error_ = true;
2242 return;
2243
2244 case elfcpp::R_X86_64_NONE:
2245 gold_unreachable();
2246 }
2247 }
2248
2249 // Return whether we need to make a PLT entry for a relocation of the
2250 // given type against a STT_GNU_IFUNC symbol.
2251
2252 template<int size>
2253 bool
2254 Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc(
2255 Sized_relobj_file<size, false>* object,
2256 unsigned int r_type)
2257 {
2258 int flags = Scan::get_reference_flags(r_type);
2259 if (flags & Symbol::TLS_REF)
2260 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
2261 object->name().c_str(), r_type);
2262 return flags != 0;
2263 }
2264
2265 // Scan a relocation for a local symbol.
2266
2267 template<int size>
2268 inline void
2269 Target_x86_64<size>::Scan::local(Symbol_table* symtab,
2270 Layout* layout,
2271 Target_x86_64<size>* target,
2272 Sized_relobj_file<size, false>* object,
2273 unsigned int data_shndx,
2274 Output_section* output_section,
2275 const elfcpp::Rela<size, false>& reloc,
2276 unsigned int r_type,
2277 const elfcpp::Sym<size, false>& lsym,
2278 bool is_discarded)
2279 {
2280 if (is_discarded)
2281 return;
2282
2283 // A local STT_GNU_IFUNC symbol may require a PLT entry.
2284 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
2285 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
2286 {
2287 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2288 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
2289 }
2290
2291 switch (r_type)
2292 {
2293 case elfcpp::R_X86_64_NONE:
2294 case elfcpp::R_X86_64_GNU_VTINHERIT:
2295 case elfcpp::R_X86_64_GNU_VTENTRY:
2296 break;
2297
2298 case elfcpp::R_X86_64_64:
2299 // If building a shared library (or a position-independent
2300 // executable), we need to create a dynamic relocation for this
2301 // location. The relocation applied at link time will apply the
2302 // link-time value, so we flag the location with an
2303 // R_X86_64_RELATIVE relocation so the dynamic loader can
2304 // relocate it easily.
2305 if (parameters->options().output_is_position_independent())
2306 {
2307 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2308 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2309 rela_dyn->add_local_relative(object, r_sym,
2310 (size == 32
2311 ? elfcpp::R_X86_64_RELATIVE64
2312 : elfcpp::R_X86_64_RELATIVE),
2313 output_section, data_shndx,
2314 reloc.get_r_offset(),
2315 reloc.get_r_addend(), is_ifunc);
2316 }
2317 break;
2318
2319 case elfcpp::R_X86_64_32:
2320 case elfcpp::R_X86_64_32S:
2321 case elfcpp::R_X86_64_16:
2322 case elfcpp::R_X86_64_8:
2323 // If building a shared library (or a position-independent
2324 // executable), we need to create a dynamic relocation for this
2325 // location. We can't use an R_X86_64_RELATIVE relocation
2326 // because that is always a 64-bit relocation.
2327 if (parameters->options().output_is_position_independent())
2328 {
2329 // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32.
2330 if (size == 32 && r_type == elfcpp::R_X86_64_32)
2331 {
2332 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2333 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2334 rela_dyn->add_local_relative(object, r_sym,
2335 elfcpp::R_X86_64_RELATIVE,
2336 output_section, data_shndx,
2337 reloc.get_r_offset(),
2338 reloc.get_r_addend(), is_ifunc);
2339 break;
2340 }
2341
2342 this->check_non_pic(object, r_type, NULL);
2343
2344 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2345 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2346 if (lsym.get_st_type() != elfcpp::STT_SECTION)
2347 rela_dyn->add_local(object, r_sym, r_type, output_section,
2348 data_shndx, reloc.get_r_offset(),
2349 reloc.get_r_addend());
2350 else
2351 {
2352 gold_assert(lsym.get_st_value() == 0);
2353 unsigned int shndx = lsym.get_st_shndx();
2354 bool is_ordinary;
2355 shndx = object->adjust_sym_shndx(r_sym, shndx,
2356 &is_ordinary);
2357 if (!is_ordinary)
2358 object->error(_("section symbol %u has bad shndx %u"),
2359 r_sym, shndx);
2360 else
2361 rela_dyn->add_local_section(object, shndx,
2362 r_type, output_section,
2363 data_shndx, reloc.get_r_offset(),
2364 reloc.get_r_addend());
2365 }
2366 }
2367 break;
2368
2369 case elfcpp::R_X86_64_PC64:
2370 case elfcpp::R_X86_64_PC32:
2371 case elfcpp::R_X86_64_PC16:
2372 case elfcpp::R_X86_64_PC8:
2373 break;
2374
2375 case elfcpp::R_X86_64_PLT32:
2376 // Since we know this is a local symbol, we can handle this as a
2377 // PC32 reloc.
2378 break;
2379
2380 case elfcpp::R_X86_64_GOTPC32:
2381 case elfcpp::R_X86_64_GOTOFF64:
2382 case elfcpp::R_X86_64_GOTPC64:
2383 case elfcpp::R_X86_64_PLTOFF64:
2384 // We need a GOT section.
2385 target->got_section(symtab, layout);
2386 // For PLTOFF64, we'd normally want a PLT section, but since we
2387 // know this is a local symbol, no PLT is needed.
2388 break;
2389
2390 case elfcpp::R_X86_64_GOT64:
2391 case elfcpp::R_X86_64_GOT32:
2392 case elfcpp::R_X86_64_GOTPCREL64:
2393 case elfcpp::R_X86_64_GOTPCREL:
2394 case elfcpp::R_X86_64_GOTPLT64:
2395 {
2396 // The symbol requires a GOT entry.
2397 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2398 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2399
2400 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
2401 // lets function pointers compare correctly with shared
2402 // libraries. Otherwise we would need an IRELATIVE reloc.
2403 bool is_new;
2404 if (is_ifunc)
2405 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
2406 else
2407 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
2408 if (is_new)
2409 {
2410 // If we are generating a shared object, we need to add a
2411 // dynamic relocation for this symbol's GOT entry.
2412 if (parameters->options().output_is_position_independent())
2413 {
2414 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2415 // R_X86_64_RELATIVE assumes a 64-bit relocation.
2416 if (r_type != elfcpp::R_X86_64_GOT32)
2417 {
2418 unsigned int got_offset =
2419 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
2420 rela_dyn->add_local_relative(object, r_sym,
2421 elfcpp::R_X86_64_RELATIVE,
2422 got, got_offset, 0, is_ifunc);
2423 }
2424 else
2425 {
2426 this->check_non_pic(object, r_type, NULL);
2427
2428 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2429 rela_dyn->add_local(
2430 object, r_sym, r_type, got,
2431 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
2432 }
2433 }
2434 }
2435 // For GOTPLT64, we'd normally want a PLT section, but since
2436 // we know this is a local symbol, no PLT is needed.
2437 }
2438 break;
2439
2440 case elfcpp::R_X86_64_COPY:
2441 case elfcpp::R_X86_64_GLOB_DAT:
2442 case elfcpp::R_X86_64_JUMP_SLOT:
2443 case elfcpp::R_X86_64_RELATIVE:
2444 case elfcpp::R_X86_64_IRELATIVE:
2445 // These are outstanding tls relocs, which are unexpected when linking
2446 case elfcpp::R_X86_64_TPOFF64:
2447 case elfcpp::R_X86_64_DTPMOD64:
2448 case elfcpp::R_X86_64_TLSDESC:
2449 gold_error(_("%s: unexpected reloc %u in object file"),
2450 object->name().c_str(), r_type);
2451 break;
2452
2453 // These are initial tls relocs, which are expected when linking
2454 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2455 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2456 case elfcpp::R_X86_64_TLSDESC_CALL:
2457 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2458 case elfcpp::R_X86_64_DTPOFF32:
2459 case elfcpp::R_X86_64_DTPOFF64:
2460 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2461 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2462 {
2463 bool output_is_shared = parameters->options().shared();
2464 const tls::Tls_optimization optimized_type
2465 = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared,
2466 r_type);
2467 switch (r_type)
2468 {
2469 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2470 if (optimized_type == tls::TLSOPT_NONE)
2471 {
2472 // Create a pair of GOT entries for the module index and
2473 // dtv-relative offset.
2474 Output_data_got<64, false>* got
2475 = target->got_section(symtab, layout);
2476 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2477 unsigned int shndx = lsym.get_st_shndx();
2478 bool is_ordinary;
2479 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
2480 if (!is_ordinary)
2481 object->error(_("local symbol %u has bad shndx %u"),
2482 r_sym, shndx);
2483 else
2484 got->add_local_pair_with_rel(object, r_sym,
2485 shndx,
2486 GOT_TYPE_TLS_PAIR,
2487 target->rela_dyn_section(layout),
2488 elfcpp::R_X86_64_DTPMOD64);
2489 }
2490 else if (optimized_type != tls::TLSOPT_TO_LE)
2491 unsupported_reloc_local(object, r_type);
2492 break;
2493
2494 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2495 target->define_tls_base_symbol(symtab, layout);
2496 if (optimized_type == tls::TLSOPT_NONE)
2497 {
2498 // Create reserved PLT and GOT entries for the resolver.
2499 target->reserve_tlsdesc_entries(symtab, layout);
2500
2501 // Generate a double GOT entry with an
2502 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
2503 // is resolved lazily, so the GOT entry needs to be in
2504 // an area in .got.plt, not .got. Call got_section to
2505 // make sure the section has been created.
2506 target->got_section(symtab, layout);
2507 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2508 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2509 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
2510 {
2511 unsigned int got_offset = got->add_constant(0);
2512 got->add_constant(0);
2513 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
2514 got_offset);
2515 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2516 // We store the arguments we need in a vector, and
2517 // use the index into the vector as the parameter
2518 // to pass to the target specific routines.
2519 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
2520 void* arg = reinterpret_cast<void*>(intarg);
2521 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
2522 got, got_offset, 0);
2523 }
2524 }
2525 else if (optimized_type != tls::TLSOPT_TO_LE)
2526 unsupported_reloc_local(object, r_type);
2527 break;
2528
2529 case elfcpp::R_X86_64_TLSDESC_CALL:
2530 break;
2531
2532 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2533 if (optimized_type == tls::TLSOPT_NONE)
2534 {
2535 // Create a GOT entry for the module index.
2536 target->got_mod_index_entry(symtab, layout, object);
2537 }
2538 else if (optimized_type != tls::TLSOPT_TO_LE)
2539 unsupported_reloc_local(object, r_type);
2540 break;
2541
2542 case elfcpp::R_X86_64_DTPOFF32:
2543 case elfcpp::R_X86_64_DTPOFF64:
2544 break;
2545
2546 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2547 layout->set_has_static_tls();
2548 if (optimized_type == tls::TLSOPT_NONE)
2549 {
2550 // Create a GOT entry for the tp-relative offset.
2551 Output_data_got<64, false>* got
2552 = target->got_section(symtab, layout);
2553 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2554 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET,
2555 target->rela_dyn_section(layout),
2556 elfcpp::R_X86_64_TPOFF64);
2557 }
2558 else if (optimized_type != tls::TLSOPT_TO_LE)
2559 unsupported_reloc_local(object, r_type);
2560 break;
2561
2562 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2563 layout->set_has_static_tls();
2564 if (output_is_shared)
2565 unsupported_reloc_local(object, r_type);
2566 break;
2567
2568 default:
2569 gold_unreachable();
2570 }
2571 }
2572 break;
2573
2574 case elfcpp::R_X86_64_SIZE32:
2575 case elfcpp::R_X86_64_SIZE64:
2576 default:
2577 gold_error(_("%s: unsupported reloc %u against local symbol"),
2578 object->name().c_str(), r_type);
2579 break;
2580 }
2581 }
2582
2583
2584 // Report an unsupported relocation against a global symbol.
2585
2586 template<int size>
2587 void
2588 Target_x86_64<size>::Scan::unsupported_reloc_global(
2589 Sized_relobj_file<size, false>* object,
2590 unsigned int r_type,
2591 Symbol* gsym)
2592 {
2593 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2594 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2595 }
2596
2597 // Returns true if this relocation type could be that of a function pointer.
2598 template<int size>
2599 inline bool
2600 Target_x86_64<size>::Scan::possible_function_pointer_reloc(unsigned int r_type)
2601 {
2602 switch (r_type)
2603 {
2604 case elfcpp::R_X86_64_64:
2605 case elfcpp::R_X86_64_32:
2606 case elfcpp::R_X86_64_32S:
2607 case elfcpp::R_X86_64_16:
2608 case elfcpp::R_X86_64_8:
2609 case elfcpp::R_X86_64_GOT64:
2610 case elfcpp::R_X86_64_GOT32:
2611 case elfcpp::R_X86_64_GOTPCREL64:
2612 case elfcpp::R_X86_64_GOTPCREL:
2613 case elfcpp::R_X86_64_GOTPLT64:
2614 {
2615 return true;
2616 }
2617 }
2618 return false;
2619 }
2620
2621 // For safe ICF, scan a relocation for a local symbol to check if it
2622 // corresponds to a function pointer being taken. In that case mark
2623 // the function whose pointer was taken as not foldable.
2624
2625 template<int size>
2626 inline bool
2627 Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer(
2628 Symbol_table* ,
2629 Layout* ,
2630 Target_x86_64<size>* ,
2631 Sized_relobj_file<size, false>* ,
2632 unsigned int ,
2633 Output_section* ,
2634 const elfcpp::Rela<size, false>& ,
2635 unsigned int r_type,
2636 const elfcpp::Sym<size, false>&)
2637 {
2638 // When building a shared library, do not fold any local symbols as it is
2639 // not possible to distinguish pointer taken versus a call by looking at
2640 // the relocation types.
2641 return (parameters->options().shared()
2642 || possible_function_pointer_reloc(r_type));
2643 }
2644
2645 // For safe ICF, scan a relocation for a global symbol to check if it
2646 // corresponds to a function pointer being taken. In that case mark
2647 // the function whose pointer was taken as not foldable.
2648
2649 template<int size>
2650 inline bool
2651 Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer(
2652 Symbol_table*,
2653 Layout* ,
2654 Target_x86_64<size>* ,
2655 Sized_relobj_file<size, false>* ,
2656 unsigned int ,
2657 Output_section* ,
2658 const elfcpp::Rela<size, false>& ,
2659 unsigned int r_type,
2660 Symbol* gsym)
2661 {
2662 // When building a shared library, do not fold symbols whose visibility
2663 // is hidden, internal or protected.
2664 return ((parameters->options().shared()
2665 && (gsym->visibility() == elfcpp::STV_INTERNAL
2666 || gsym->visibility() == elfcpp::STV_PROTECTED
2667 || gsym->visibility() == elfcpp::STV_HIDDEN))
2668 || possible_function_pointer_reloc(r_type));
2669 }
2670
2671 // Scan a relocation for a global symbol.
2672
2673 template<int size>
2674 inline void
2675 Target_x86_64<size>::Scan::global(Symbol_table* symtab,
2676 Layout* layout,
2677 Target_x86_64<size>* target,
2678 Sized_relobj_file<size, false>* object,
2679 unsigned int data_shndx,
2680 Output_section* output_section,
2681 const elfcpp::Rela<size, false>& reloc,
2682 unsigned int r_type,
2683 Symbol* gsym)
2684 {
2685 // A STT_GNU_IFUNC symbol may require a PLT entry.
2686 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2687 && this->reloc_needs_plt_for_ifunc(object, r_type))
2688 target->make_plt_entry(symtab, layout, gsym);
2689
2690 switch (r_type)
2691 {
2692 case elfcpp::R_X86_64_NONE:
2693 case elfcpp::R_X86_64_GNU_VTINHERIT:
2694 case elfcpp::R_X86_64_GNU_VTENTRY:
2695 break;
2696
2697 case elfcpp::R_X86_64_64:
2698 case elfcpp::R_X86_64_32:
2699 case elfcpp::R_X86_64_32S:
2700 case elfcpp::R_X86_64_16:
2701 case elfcpp::R_X86_64_8:
2702 {
2703 // Make a PLT entry if necessary.
2704 if (gsym->needs_plt_entry())
2705 {
2706 target->make_plt_entry(symtab, layout, gsym);
2707 // Since this is not a PC-relative relocation, we may be
2708 // taking the address of a function. In that case we need to
2709 // set the entry in the dynamic symbol table to the address of
2710 // the PLT entry.
2711 if (gsym->is_from_dynobj() && !parameters->options().shared())
2712 gsym->set_needs_dynsym_value();
2713 }
2714 // Make a dynamic relocation if necessary.
2715 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2716 {
2717 if (gsym->may_need_copy_reloc())
2718 {
2719 target->copy_reloc(symtab, layout, object,
2720 data_shndx, output_section, gsym, reloc);
2721 }
2722 else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
2723 || (size == 32 && r_type == elfcpp::R_X86_64_32))
2724 && gsym->type() == elfcpp::STT_GNU_IFUNC
2725 && gsym->can_use_relative_reloc(false)
2726 && !gsym->is_from_dynobj()
2727 && !gsym->is_undefined()
2728 && !gsym->is_preemptible())
2729 {
2730 // Use an IRELATIVE reloc for a locally defined
2731 // STT_GNU_IFUNC symbol. This makes a function
2732 // address in a PIE executable match the address in a
2733 // shared library that it links against.
2734 Reloc_section* rela_dyn =
2735 target->rela_irelative_section(layout);
2736 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
2737 rela_dyn->add_symbolless_global_addend(gsym, r_type,
2738 output_section, object,
2739 data_shndx,
2740 reloc.get_r_offset(),
2741 reloc.get_r_addend());
2742 }
2743 else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
2744 || (size == 32 && r_type == elfcpp::R_X86_64_32))
2745 && gsym->can_use_relative_reloc(false))
2746 {
2747 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2748 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
2749 output_section, object,
2750 data_shndx,
2751 reloc.get_r_offset(),
2752 reloc.get_r_addend(), false);
2753 }
2754 else
2755 {
2756 this->check_non_pic(object, r_type, gsym);
2757 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2758 rela_dyn->add_global(gsym, r_type, output_section, object,
2759 data_shndx, reloc.get_r_offset(),
2760 reloc.get_r_addend());
2761 }
2762 }
2763 }
2764 break;
2765
2766 case elfcpp::R_X86_64_PC64:
2767 case elfcpp::R_X86_64_PC32:
2768 case elfcpp::R_X86_64_PC16:
2769 case elfcpp::R_X86_64_PC8:
2770 {
2771 // Make a PLT entry if necessary.
2772 if (gsym->needs_plt_entry())
2773 target->make_plt_entry(symtab, layout, gsym);
2774 // Make a dynamic relocation if necessary.
2775 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2776 {
2777 if (gsym->may_need_copy_reloc())
2778 {
2779 target->copy_reloc(symtab, layout, object,
2780 data_shndx, output_section, gsym, reloc);
2781 }
2782 else
2783 {
2784 this->check_non_pic(object, r_type, gsym);
2785 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2786 rela_dyn->add_global(gsym, r_type, output_section, object,
2787 data_shndx, reloc.get_r_offset(),
2788 reloc.get_r_addend());
2789 }
2790 }
2791 }
2792 break;
2793
2794 case elfcpp::R_X86_64_GOT64:
2795 case elfcpp::R_X86_64_GOT32:
2796 case elfcpp::R_X86_64_GOTPCREL64:
2797 case elfcpp::R_X86_64_GOTPCREL:
2798 case elfcpp::R_X86_64_GOTPLT64:
2799 {
2800 // The symbol requires a GOT entry.
2801 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2802 if (gsym->final_value_is_known())
2803 {
2804 // For a STT_GNU_IFUNC symbol we want the PLT address.
2805 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2806 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2807 else
2808 got->add_global(gsym, GOT_TYPE_STANDARD);
2809 }
2810 else
2811 {
2812 // If this symbol is not fully resolved, we need to add a
2813 // dynamic relocation for it.
2814 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2815
2816 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2817 //
2818 // 1) The symbol may be defined in some other module.
2819 //
2820 // 2) We are building a shared library and this is a
2821 // protected symbol; using GLOB_DAT means that the dynamic
2822 // linker can use the address of the PLT in the main
2823 // executable when appropriate so that function address
2824 // comparisons work.
2825 //
2826 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2827 // code, again so that function address comparisons work.
2828 if (gsym->is_from_dynobj()
2829 || gsym->is_undefined()
2830 || gsym->is_preemptible()
2831 || (gsym->visibility() == elfcpp::STV_PROTECTED
2832 && parameters->options().shared())
2833 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2834 && parameters->options().output_is_position_independent()))
2835 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn,
2836 elfcpp::R_X86_64_GLOB_DAT);
2837 else
2838 {
2839 // For a STT_GNU_IFUNC symbol we want to write the PLT
2840 // offset into the GOT, so that function pointer
2841 // comparisons work correctly.
2842 bool is_new;
2843 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2844 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2845 else
2846 {
2847 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2848 // Tell the dynamic linker to use the PLT address
2849 // when resolving relocations.
2850 if (gsym->is_from_dynobj()
2851 && !parameters->options().shared())
2852 gsym->set_needs_dynsym_value();
2853 }
2854 if (is_new)
2855 {
2856 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2857 rela_dyn->add_global_relative(gsym,
2858 elfcpp::R_X86_64_RELATIVE,
2859 got, got_off, 0, false);
2860 }
2861 }
2862 }
2863 // For GOTPLT64, we also need a PLT entry (but only if the
2864 // symbol is not fully resolved).
2865 if (r_type == elfcpp::R_X86_64_GOTPLT64
2866 && !gsym->final_value_is_known())
2867 target->make_plt_entry(symtab, layout, gsym);
2868 }
2869 break;
2870
2871 case elfcpp::R_X86_64_PLT32:
2872 // If the symbol is fully resolved, this is just a PC32 reloc.
2873 // Otherwise we need a PLT entry.
2874 if (gsym->final_value_is_known())
2875 break;
2876 // If building a shared library, we can also skip the PLT entry
2877 // if the symbol is defined in the output file and is protected
2878 // or hidden.
2879 if (gsym->is_defined()
2880 && !gsym->is_from_dynobj()
2881 && !gsym->is_preemptible())
2882 break;
2883 target->make_plt_entry(symtab, layout, gsym);
2884 break;
2885
2886 case elfcpp::R_X86_64_GOTPC32:
2887 case elfcpp::R_X86_64_GOTOFF64:
2888 case elfcpp::R_X86_64_GOTPC64:
2889 case elfcpp::R_X86_64_PLTOFF64:
2890 // We need a GOT section.
2891 target->got_section(symtab, layout);
2892 // For PLTOFF64, we also need a PLT entry (but only if the
2893 // symbol is not fully resolved).
2894 if (r_type == elfcpp::R_X86_64_PLTOFF64
2895 && !gsym->final_value_is_known())
2896 target->make_plt_entry(symtab, layout, gsym);
2897 break;
2898
2899 case elfcpp::R_X86_64_COPY:
2900 case elfcpp::R_X86_64_GLOB_DAT:
2901 case elfcpp::R_X86_64_JUMP_SLOT:
2902 case elfcpp::R_X86_64_RELATIVE:
2903 case elfcpp::R_X86_64_IRELATIVE:
2904 // These are outstanding tls relocs, which are unexpected when linking
2905 case elfcpp::R_X86_64_TPOFF64:
2906 case elfcpp::R_X86_64_DTPMOD64:
2907 case elfcpp::R_X86_64_TLSDESC:
2908 gold_error(_("%s: unexpected reloc %u in object file"),
2909 object->name().c_str(), r_type);
2910 break;
2911
2912 // These are initial tls relocs, which are expected for global()
2913 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2914 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2915 case elfcpp::R_X86_64_TLSDESC_CALL:
2916 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2917 case elfcpp::R_X86_64_DTPOFF32:
2918 case elfcpp::R_X86_64_DTPOFF64:
2919 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2920 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2921 {
2922 const bool is_final = gsym->final_value_is_known();
2923 const tls::Tls_optimization optimized_type
2924 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
2925 switch (r_type)
2926 {
2927 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2928 if (optimized_type == tls::TLSOPT_NONE)
2929 {
2930 // Create a pair of GOT entries for the module index and
2931 // dtv-relative offset.
2932 Output_data_got<64, false>* got
2933 = target->got_section(symtab, layout);
2934 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2935 target->rela_dyn_section(layout),
2936 elfcpp::R_X86_64_DTPMOD64,
2937 elfcpp::R_X86_64_DTPOFF64);
2938 }
2939 else if (optimized_type == tls::TLSOPT_TO_IE)
2940 {
2941 // Create a GOT entry for the tp-relative offset.
2942 Output_data_got<64, false>* got
2943 = target->got_section(symtab, layout);
2944 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2945 target->rela_dyn_section(layout),
2946 elfcpp::R_X86_64_TPOFF64);
2947 }
2948 else if (optimized_type != tls::TLSOPT_TO_LE)
2949 unsupported_reloc_global(object, r_type, gsym);
2950 break;
2951
2952 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2953 target->define_tls_base_symbol(symtab, layout);
2954 if (optimized_type == tls::TLSOPT_NONE)
2955 {
2956 // Create reserved PLT and GOT entries for the resolver.
2957 target->reserve_tlsdesc_entries(symtab, layout);
2958
2959 // Create a double GOT entry with an R_X86_64_TLSDESC
2960 // reloc. The R_X86_64_TLSDESC reloc is resolved
2961 // lazily, so the GOT entry needs to be in an area in
2962 // .got.plt, not .got. Call got_section to make sure
2963 // the section has been created.
2964 target->got_section(symtab, layout);
2965 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2966 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2967 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2968 elfcpp::R_X86_64_TLSDESC, 0);
2969 }
2970 else if (optimized_type == tls::TLSOPT_TO_IE)
2971 {
2972 // Create a GOT entry for the tp-relative offset.
2973 Output_data_got<64, false>* got
2974 = target->got_section(symtab, layout);
2975 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2976 target->rela_dyn_section(layout),
2977 elfcpp::R_X86_64_TPOFF64);
2978 }
2979 else if (optimized_type != tls::TLSOPT_TO_LE)
2980 unsupported_reloc_global(object, r_type, gsym);
2981 break;
2982
2983 case elfcpp::R_X86_64_TLSDESC_CALL:
2984 break;
2985
2986 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2987 if (optimized_type == tls::TLSOPT_NONE)
2988 {
2989 // Create a GOT entry for the module index.
2990 target->got_mod_index_entry(symtab, layout, object);
2991 }
2992 else if (optimized_type != tls::TLSOPT_TO_LE)
2993 unsupported_reloc_global(object, r_type, gsym);
2994 break;
2995
2996 case elfcpp::R_X86_64_DTPOFF32:
2997 case elfcpp::R_X86_64_DTPOFF64:
2998 break;
2999
3000 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3001 layout->set_has_static_tls();
3002 if (optimized_type == tls::TLSOPT_NONE)
3003 {
3004 // Create a GOT entry for the tp-relative offset.
3005 Output_data_got<64, false>* got
3006 = target->got_section(symtab, layout);
3007 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
3008 target->rela_dyn_section(layout),
3009 elfcpp::R_X86_64_TPOFF64);
3010 }
3011 else if (optimized_type != tls::TLSOPT_TO_LE)
3012 unsupported_reloc_global(object, r_type, gsym);
3013 break;
3014
3015 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3016 layout->set_has_static_tls();
3017 if (parameters->options().shared())
3018 unsupported_reloc_global(object, r_type, gsym);
3019 break;
3020
3021 default:
3022 gold_unreachable();
3023 }
3024 }
3025 break;
3026
3027 case elfcpp::R_X86_64_SIZE32:
3028 case elfcpp::R_X86_64_SIZE64:
3029 default:
3030 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
3031 object->name().c_str(), r_type,
3032 gsym->demangled_name().c_str());
3033 break;
3034 }
3035 }
3036
3037 template<int size>
3038 void
3039 Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab,
3040 Layout* layout,
3041 Sized_relobj_file<size, false>* object,
3042 unsigned int data_shndx,
3043 unsigned int sh_type,
3044 const unsigned char* prelocs,
3045 size_t reloc_count,
3046 Output_section* output_section,
3047 bool needs_special_offset_handling,
3048 size_t local_symbol_count,
3049 const unsigned char* plocal_symbols)
3050 {
3051
3052 if (sh_type == elfcpp::SHT_REL)
3053 {
3054 return;
3055 }
3056
3057 gold::gc_process_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
3058 typename Target_x86_64<size>::Scan,
3059 typename Target_x86_64<size>::Relocatable_size_for_reloc>(
3060 symtab,
3061 layout,
3062 this,
3063 object,
3064 data_shndx,
3065 prelocs,
3066 reloc_count,
3067 output_section,
3068 needs_special_offset_handling,
3069 local_symbol_count,
3070 plocal_symbols);
3071
3072 }
3073 // Scan relocations for a section.
3074
3075 template<int size>
3076 void
3077 Target_x86_64<size>::scan_relocs(Symbol_table* symtab,
3078 Layout* layout,
3079 Sized_relobj_file<size, false>* object,
3080 unsigned int data_shndx,
3081 unsigned int sh_type,
3082 const unsigned char* prelocs,
3083 size_t reloc_count,
3084 Output_section* output_section,
3085 bool needs_special_offset_handling,
3086 size_t local_symbol_count,
3087 const unsigned char* plocal_symbols)
3088 {
3089 if (sh_type == elfcpp::SHT_REL)
3090 {
3091 gold_error(_("%s: unsupported REL reloc section"),
3092 object->name().c_str());
3093 return;
3094 }
3095
3096 gold::scan_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
3097 typename Target_x86_64<size>::Scan>(
3098 symtab,
3099 layout,
3100 this,
3101 object,
3102 data_shndx,
3103 prelocs,
3104 reloc_count,
3105 output_section,
3106 needs_special_offset_handling,
3107 local_symbol_count,
3108 plocal_symbols);
3109 }
3110
3111 // Finalize the sections.
3112
3113 template<int size>
3114 void
3115 Target_x86_64<size>::do_finalize_sections(
3116 Layout* layout,
3117 const Input_objects*,
3118 Symbol_table* symtab)
3119 {
3120 const Reloc_section* rel_plt = (this->plt_ == NULL
3121 ? NULL
3122 : this->plt_->rela_plt());
3123 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
3124 this->rela_dyn_, true, false);
3125
3126 // Fill in some more dynamic tags.
3127 Output_data_dynamic* const odyn = layout->dynamic_data();
3128 if (odyn != NULL)
3129 {
3130 if (this->plt_ != NULL
3131 && this->plt_->output_section() != NULL
3132 && this->plt_->has_tlsdesc_entry())
3133 {
3134 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
3135 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
3136 this->got_->finalize_data_size();
3137 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
3138 this->plt_, plt_offset);
3139 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
3140 this->got_, got_offset);
3141 }
3142 }
3143
3144 // Emit any relocs we saved in an attempt to avoid generating COPY
3145 // relocs.
3146 if (this->copy_relocs_.any_saved_relocs())
3147 this->copy_relocs_.emit(this->rela_dyn_section(layout));
3148
3149 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
3150 // the .got.plt section.
3151 Symbol* sym = this->global_offset_table_;
3152 if (sym != NULL)
3153 {
3154 uint64_t data_size = this->got_plt_->current_data_size();
3155 symtab->get_sized_symbol<size>(sym)->set_symsize(data_size);
3156 }
3157
3158 if (parameters->doing_static_link()
3159 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
3160 {
3161 // If linking statically, make sure that the __rela_iplt symbols
3162 // were defined if necessary, even if we didn't create a PLT.
3163 static const Define_symbol_in_segment syms[] =
3164 {
3165 {
3166 "__rela_iplt_start", // name
3167 elfcpp::PT_LOAD, // segment_type
3168 elfcpp::PF_W, // segment_flags_set
3169 elfcpp::PF(0), // segment_flags_clear
3170 0, // value
3171 0, // size
3172 elfcpp::STT_NOTYPE, // type
3173 elfcpp::STB_GLOBAL, // binding
3174 elfcpp::STV_HIDDEN, // visibility
3175 0, // nonvis
3176 Symbol::SEGMENT_START, // offset_from_base
3177 true // only_if_ref
3178 },
3179 {
3180 "__rela_iplt_end", // name
3181 elfcpp::PT_LOAD, // segment_type
3182 elfcpp::PF_W, // segment_flags_set
3183 elfcpp::PF(0), // segment_flags_clear
3184 0, // value
3185 0, // size
3186 elfcpp::STT_NOTYPE, // type
3187 elfcpp::STB_GLOBAL, // binding
3188 elfcpp::STV_HIDDEN, // visibility
3189 0, // nonvis
3190 Symbol::SEGMENT_START, // offset_from_base
3191 true // only_if_ref
3192 }
3193 };
3194
3195 symtab->define_symbols(layout, 2, syms,
3196 layout->script_options()->saw_sections_clause());
3197 }
3198 }
3199
3200 // Perform a relocation.
3201
3202 template<int size>
3203 inline bool
3204 Target_x86_64<size>::Relocate::relocate(
3205 const Relocate_info<size, false>* relinfo,
3206 Target_x86_64<size>* target,
3207 Output_section*,
3208 size_t relnum,
3209 const elfcpp::Rela<size, false>& rela,
3210 unsigned int r_type,
3211 const Sized_symbol<size>* gsym,
3212 const Symbol_value<size>* psymval,
3213 unsigned char* view,
3214 typename elfcpp::Elf_types<size>::Elf_Addr address,
3215 section_size_type view_size)
3216 {
3217 if (this->skip_call_tls_get_addr_)
3218 {
3219 if ((r_type != elfcpp::R_X86_64_PLT32
3220 && r_type != elfcpp::R_X86_64_PC32)
3221 || gsym == NULL
3222 || strcmp(gsym->name(), "__tls_get_addr") != 0)
3223 {
3224 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3225 _("missing expected TLS relocation"));
3226 }
3227 else
3228 {
3229 this->skip_call_tls_get_addr_ = false;
3230 return false;
3231 }
3232 }
3233
3234 if (view == NULL)
3235 return true;
3236
3237 const Sized_relobj_file<size, false>* object = relinfo->object;
3238
3239 // Pick the value to use for symbols defined in the PLT.
3240 Symbol_value<size> symval;
3241 if (gsym != NULL
3242 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
3243 {
3244 symval.set_output_value(target->plt_address_for_global(gsym));
3245 psymval = &symval;
3246 }
3247 else if (gsym == NULL && psymval->is_ifunc_symbol())
3248 {
3249 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3250 if (object->local_has_plt_offset(r_sym))
3251 {
3252 symval.set_output_value(target->plt_address_for_local(object, r_sym));
3253 psymval = &symval;
3254 }
3255 }
3256
3257 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3258
3259 // Get the GOT offset if needed.
3260 // The GOT pointer points to the end of the GOT section.
3261 // We need to subtract the size of the GOT section to get
3262 // the actual offset to use in the relocation.
3263 bool have_got_offset = false;
3264 unsigned int got_offset = 0;
3265 switch (r_type)
3266 {
3267 case elfcpp::R_X86_64_GOT32:
3268 case elfcpp::R_X86_64_GOT64:
3269 case elfcpp::R_X86_64_GOTPLT64:
3270 case elfcpp::R_X86_64_GOTPCREL:
3271 case elfcpp::R_X86_64_GOTPCREL64:
3272 if (gsym != NULL)
3273 {
3274 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
3275 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
3276 }
3277 else
3278 {
3279 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3280 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
3281 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
3282 - target->got_size());
3283 }
3284 have_got_offset = true;
3285 break;
3286
3287 default:
3288 break;
3289 }
3290
3291 switch (r_type)
3292 {
3293 case elfcpp::R_X86_64_NONE:
3294 case elfcpp::R_X86_64_GNU_VTINHERIT:
3295 case elfcpp::R_X86_64_GNU_VTENTRY:
3296 break;
3297
3298 case elfcpp::R_X86_64_64:
3299 Relocate_functions<size, false>::rela64(view, object, psymval, addend);
3300 break;
3301
3302 case elfcpp::R_X86_64_PC64:
3303 Relocate_functions<size, false>::pcrela64(view, object, psymval, addend,
3304 address);
3305 break;
3306
3307 case elfcpp::R_X86_64_32:
3308 // FIXME: we need to verify that value + addend fits into 32 bits:
3309 // uint64_t x = value + addend;
3310 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
3311 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
3312 Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3313 break;
3314
3315 case elfcpp::R_X86_64_32S:
3316 // FIXME: we need to verify that value + addend fits into 32 bits:
3317 // int64_t x = value + addend; // note this quantity is signed!
3318 // x == static_cast<int64_t>(static_cast<int32_t>(x))
3319 Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3320 break;
3321
3322 case elfcpp::R_X86_64_PC32:
3323 Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3324 address);
3325 break;
3326
3327 case elfcpp::R_X86_64_16:
3328 Relocate_functions<size, false>::rela16(view, object, psymval, addend);
3329 break;
3330
3331 case elfcpp::R_X86_64_PC16:
3332 Relocate_functions<size, false>::pcrela16(view, object, psymval, addend,
3333 address);
3334 break;
3335
3336 case elfcpp::R_X86_64_8:
3337 Relocate_functions<size, false>::rela8(view, object, psymval, addend);
3338 break;
3339
3340 case elfcpp::R_X86_64_PC8:
3341 Relocate_functions<size, false>::pcrela8(view, object, psymval, addend,
3342 address);
3343 break;
3344
3345 case elfcpp::R_X86_64_PLT32:
3346 gold_assert(gsym == NULL
3347 || gsym->has_plt_offset()
3348 || gsym->final_value_is_known()
3349 || (gsym->is_defined()
3350 && !gsym->is_from_dynobj()
3351 && !gsym->is_preemptible()));
3352 // Note: while this code looks the same as for R_X86_64_PC32, it
3353 // behaves differently because psymval was set to point to
3354 // the PLT entry, rather than the symbol, in Scan::global().
3355 Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3356 address);
3357 break;
3358
3359 case elfcpp::R_X86_64_PLTOFF64:
3360 {
3361 gold_assert(gsym);
3362 gold_assert(gsym->has_plt_offset()
3363 || gsym->final_value_is_known());
3364 typename elfcpp::Elf_types<size>::Elf_Addr got_address;
3365 got_address = target->got_section(NULL, NULL)->address();
3366 Relocate_functions<size, false>::rela64(view, object, psymval,
3367 addend - got_address);
3368 }
3369
3370 case elfcpp::R_X86_64_GOT32:
3371 gold_assert(have_got_offset);
3372 Relocate_functions<size, false>::rela32(view, got_offset, addend);
3373 break;
3374
3375 case elfcpp::R_X86_64_GOTPC32:
3376 {
3377 gold_assert(gsym);
3378 typename elfcpp::Elf_types<size>::Elf_Addr value;
3379 value = target->got_plt_section()->address();
3380 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3381 }
3382 break;
3383
3384 case elfcpp::R_X86_64_GOT64:
3385 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
3386 // Since we always add a PLT entry, this is equivalent.
3387 case elfcpp::R_X86_64_GOTPLT64:
3388 gold_assert(have_got_offset);
3389 Relocate_functions<size, false>::rela64(view, got_offset, addend);
3390 break;
3391
3392 case elfcpp::R_X86_64_GOTPC64:
3393 {
3394 gold_assert(gsym);
3395 typename elfcpp::Elf_types<size>::Elf_Addr value;
3396 value = target->got_plt_section()->address();
3397 Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3398 }
3399 break;
3400
3401 case elfcpp::R_X86_64_GOTOFF64:
3402 {
3403 typename elfcpp::Elf_types<size>::Elf_Addr value;
3404 value = (psymval->value(object, 0)
3405 - target->got_plt_section()->address());
3406 Relocate_functions<size, false>::rela64(view, value, addend);
3407 }
3408 break;
3409
3410 case elfcpp::R_X86_64_GOTPCREL:
3411 {
3412 gold_assert(have_got_offset);
3413 typename elfcpp::Elf_types<size>::Elf_Addr value;
3414 value = target->got_plt_section()->address() + got_offset;
3415 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3416 }
3417 break;
3418
3419 case elfcpp::R_X86_64_GOTPCREL64:
3420 {
3421 gold_assert(have_got_offset);
3422 typename elfcpp::Elf_types<size>::Elf_Addr value;
3423 value = target->got_plt_section()->address() + got_offset;
3424 Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3425 }
3426 break;
3427
3428 case elfcpp::R_X86_64_COPY:
3429 case elfcpp::R_X86_64_GLOB_DAT:
3430 case elfcpp::R_X86_64_JUMP_SLOT:
3431 case elfcpp::R_X86_64_RELATIVE:
3432 case elfcpp::R_X86_64_IRELATIVE:
3433 // These are outstanding tls relocs, which are unexpected when linking
3434 case elfcpp::R_X86_64_TPOFF64:
3435 case elfcpp::R_X86_64_DTPMOD64:
3436 case elfcpp::R_X86_64_TLSDESC:
3437 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3438 _("unexpected reloc %u in object file"),
3439 r_type);
3440 break;
3441
3442 // These are initial tls relocs, which are expected when linking
3443 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3444 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3445 case elfcpp::R_X86_64_TLSDESC_CALL:
3446 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3447 case elfcpp::R_X86_64_DTPOFF32:
3448 case elfcpp::R_X86_64_DTPOFF64:
3449 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3450 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3451 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
3452 view, address, view_size);
3453 break;
3454
3455 case elfcpp::R_X86_64_SIZE32:
3456 case elfcpp::R_X86_64_SIZE64:
3457 default:
3458 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3459 _("unsupported reloc %u"),
3460 r_type);
3461 break;
3462 }
3463
3464 return true;
3465 }
3466
3467 // Perform a TLS relocation.
3468
3469 template<int size>
3470 inline void
3471 Target_x86_64<size>::Relocate::relocate_tls(
3472 const Relocate_info<size, false>* relinfo,
3473 Target_x86_64<size>* target,
3474 size_t relnum,
3475 const elfcpp::Rela<size, false>& rela,
3476 unsigned int r_type,
3477 const Sized_symbol<size>* gsym,
3478 const Symbol_value<size>* psymval,
3479 unsigned char* view,
3480 typename elfcpp::Elf_types<size>::Elf_Addr address,
3481 section_size_type view_size)
3482 {
3483 Output_segment* tls_segment = relinfo->layout->tls_segment();
3484
3485 const Sized_relobj_file<size, false>* object = relinfo->object;
3486 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3487 elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr);
3488 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
3489
3490 typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0);
3491
3492 const bool is_final = (gsym == NULL
3493 ? !parameters->options().shared()
3494 : gsym->final_value_is_known());
3495 tls::Tls_optimization optimized_type
3496 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
3497 switch (r_type)
3498 {
3499 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3500 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3501 {
3502 // If this code sequence is used in a non-executable section,
3503 // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
3504 // on the assumption that it's being used by itself in a debug
3505 // section. Therefore, in the unlikely event that the code
3506 // sequence appears in a non-executable section, we simply
3507 // leave it unoptimized.
3508 optimized_type = tls::TLSOPT_NONE;
3509 }
3510 if (optimized_type == tls::TLSOPT_TO_LE)
3511 {
3512 if (tls_segment == NULL)
3513 {
3514 gold_assert(parameters->errors()->error_count() > 0
3515 || issue_undefined_symbol_error(gsym));
3516 return;
3517 }
3518 this->tls_gd_to_le(relinfo, relnum, tls_segment,
3519 rela, r_type, value, view,
3520 view_size);
3521 break;
3522 }
3523 else
3524 {
3525 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3526 ? GOT_TYPE_TLS_OFFSET
3527 : GOT_TYPE_TLS_PAIR);
3528 unsigned int got_offset;
3529 if (gsym != NULL)
3530 {
3531 gold_assert(gsym->has_got_offset(got_type));
3532 got_offset = gsym->got_offset(got_type) - target->got_size();
3533 }
3534 else
3535 {
3536 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3537 gold_assert(object->local_has_got_offset(r_sym, got_type));
3538 got_offset = (object->local_got_offset(r_sym, got_type)
3539 - target->got_size());
3540 }
3541 if (optimized_type == tls::TLSOPT_TO_IE)
3542 {
3543 value = target->got_plt_section()->address() + got_offset;
3544 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
3545 value, view, address, view_size);
3546 break;
3547 }
3548 else if (optimized_type == tls::TLSOPT_NONE)
3549 {
3550 // Relocate the field with the offset of the pair of GOT
3551 // entries.
3552 value = target->got_plt_section()->address() + got_offset;
3553 Relocate_functions<size, false>::pcrela32(view, value, addend,
3554 address);
3555 break;
3556 }
3557 }
3558 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3559 _("unsupported reloc %u"), r_type);
3560 break;
3561
3562 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3563 case elfcpp::R_X86_64_TLSDESC_CALL:
3564 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3565 {
3566 // See above comment for R_X86_64_TLSGD.
3567 optimized_type = tls::TLSOPT_NONE;
3568 }
3569 if (optimized_type == tls::TLSOPT_TO_LE)
3570 {
3571 if (tls_segment == NULL)
3572 {
3573 gold_assert(parameters->errors()->error_count() > 0
3574 || issue_undefined_symbol_error(gsym));
3575 return;
3576 }
3577 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3578 rela, r_type, value, view,
3579 view_size);
3580 break;
3581 }
3582 else
3583 {
3584 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3585 ? GOT_TYPE_TLS_OFFSET
3586 : GOT_TYPE_TLS_DESC);
3587 unsigned int got_offset = 0;
3588 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
3589 && optimized_type == tls::TLSOPT_NONE)
3590 {
3591 // We created GOT entries in the .got.tlsdesc portion of
3592 // the .got.plt section, but the offset stored in the
3593 // symbol is the offset within .got.tlsdesc.
3594 got_offset = (target->got_size()
3595 + target->got_plt_section()->data_size());
3596 }
3597 if (gsym != NULL)
3598 {
3599 gold_assert(gsym->has_got_offset(got_type));
3600 got_offset += gsym->got_offset(got_type) - target->got_size();
3601 }
3602 else
3603 {
3604 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3605 gold_assert(object->local_has_got_offset(r_sym, got_type));
3606 got_offset += (object->local_got_offset(r_sym, got_type)
3607 - target->got_size());
3608 }
3609 if (optimized_type == tls::TLSOPT_TO_IE)
3610 {
3611 if (tls_segment == NULL)
3612 {
3613 gold_assert(parameters->errors()->error_count() > 0
3614 || issue_undefined_symbol_error(gsym));
3615 return;
3616 }
3617 value = target->got_plt_section()->address() + got_offset;
3618 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
3619 rela, r_type, value, view, address,
3620 view_size);
3621 break;
3622 }
3623 else if (optimized_type == tls::TLSOPT_NONE)
3624 {
3625 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3626 {
3627 // Relocate the field with the offset of the pair of GOT
3628 // entries.
3629 value = target->got_plt_section()->address() + got_offset;
3630 Relocate_functions<size, false>::pcrela32(view, value, addend,
3631 address);
3632 }
3633 break;
3634 }
3635 }
3636 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3637 _("unsupported reloc %u"), r_type);
3638 break;
3639
3640 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3641 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3642 {
3643 // See above comment for R_X86_64_TLSGD.
3644 optimized_type = tls::TLSOPT_NONE;
3645 }
3646 if (optimized_type == tls::TLSOPT_TO_LE)
3647 {
3648 if (tls_segment == NULL)
3649 {
3650 gold_assert(parameters->errors()->error_count() > 0
3651 || issue_undefined_symbol_error(gsym));
3652 return;
3653 }
3654 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
3655 value, view, view_size);
3656 break;
3657 }
3658 else if (optimized_type == tls::TLSOPT_NONE)
3659 {
3660 // Relocate the field with the offset of the GOT entry for
3661 // the module index.
3662 unsigned int got_offset;
3663 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3664 - target->got_size());
3665 value = target->got_plt_section()->address() + got_offset;
3666 Relocate_functions<size, false>::pcrela32(view, value, addend,
3667 address);
3668 break;
3669 }
3670 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3671 _("unsupported reloc %u"), r_type);
3672 break;
3673
3674 case elfcpp::R_X86_64_DTPOFF32:
3675 // This relocation type is used in debugging information.
3676 // In that case we need to not optimize the value. If the
3677 // section is not executable, then we assume we should not
3678 // optimize this reloc. See comments above for R_X86_64_TLSGD,
3679 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
3680 // R_X86_64_TLSLD.
3681 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3682 {
3683 if (tls_segment == NULL)
3684 {
3685 gold_assert(parameters->errors()->error_count() > 0
3686 || issue_undefined_symbol_error(gsym));
3687 return;
3688 }
3689 value -= tls_segment->memsz();
3690 }
3691 Relocate_functions<size, false>::rela32(view, value, addend);
3692 break;
3693
3694 case elfcpp::R_X86_64_DTPOFF64:
3695 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
3696 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3697 {
3698 if (tls_segment == NULL)
3699 {
3700 gold_assert(parameters->errors()->error_count() > 0
3701 || issue_undefined_symbol_error(gsym));
3702 return;
3703 }
3704 value -= tls_segment->memsz();
3705 }
3706 Relocate_functions<size, false>::rela64(view, value, addend);
3707 break;
3708
3709 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3710 if (optimized_type == tls::TLSOPT_TO_LE)
3711 {
3712 if (tls_segment == NULL)
3713 {
3714 gold_assert(parameters->errors()->error_count() > 0
3715 || issue_undefined_symbol_error(gsym));
3716 return;
3717 }
3718 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
3719 tls_segment, rela,
3720 r_type, value, view,
3721 view_size);
3722 break;
3723 }
3724 else if (optimized_type == tls::TLSOPT_NONE)
3725 {
3726 // Relocate the field with the offset of the GOT entry for
3727 // the tp-relative offset of the symbol.
3728 unsigned int got_offset;
3729 if (gsym != NULL)
3730 {
3731 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
3732 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
3733 - target->got_size());
3734 }
3735 else
3736 {
3737 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3738 gold_assert(object->local_has_got_offset(r_sym,
3739 GOT_TYPE_TLS_OFFSET));
3740 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
3741 - target->got_size());
3742 }
3743 value = target->got_plt_section()->address() + got_offset;
3744 Relocate_functions<size, false>::pcrela32(view, value, addend,
3745 address);
3746 break;
3747 }
3748 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3749 _("unsupported reloc type %u"),
3750 r_type);
3751 break;
3752
3753 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3754 if (tls_segment == NULL)
3755 {
3756 gold_assert(parameters->errors()->error_count() > 0
3757 || issue_undefined_symbol_error(gsym));
3758 return;
3759 }
3760 value -= tls_segment->memsz();
3761 Relocate_functions<size, false>::rela32(view, value, addend);
3762 break;
3763 }
3764 }
3765
3766 // Do a relocation in which we convert a TLS General-Dynamic to an
3767 // Initial-Exec.
3768
3769 template<int size>
3770 inline void
3771 Target_x86_64<size>::Relocate::tls_gd_to_ie(
3772 const Relocate_info<size, false>* relinfo,
3773 size_t relnum,
3774 Output_segment*,
3775 const elfcpp::Rela<size, false>& rela,
3776 unsigned int,
3777 typename elfcpp::Elf_types<size>::Elf_Addr value,
3778 unsigned char* view,
3779 typename elfcpp::Elf_types<size>::Elf_Addr address,
3780 section_size_type view_size)
3781 {
3782 // For SIZE == 64:
3783 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3784 // .word 0x6666; rex64; call __tls_get_addr
3785 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
3786 // For SIZE == 32:
3787 // leaq foo@tlsgd(%rip),%rdi;
3788 // .word 0x6666; rex64; call __tls_get_addr
3789 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
3790
3791 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3792 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3793 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3794
3795 if (size == 64)
3796 {
3797 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3798 -4);
3799 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3800 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3801 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
3802 16);
3803 }
3804 else
3805 {
3806 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3807 -3);
3808 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3809 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
3810 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
3811 15);
3812 }
3813
3814 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3815 Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8,
3816 address);
3817
3818 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3819 // We can skip it.
3820 this->skip_call_tls_get_addr_ = true;
3821 }
3822
3823 // Do a relocation in which we convert a TLS General-Dynamic to a
3824 // Local-Exec.
3825
3826 template<int size>
3827 inline void
3828 Target_x86_64<size>::Relocate::tls_gd_to_le(
3829 const Relocate_info<size, false>* relinfo,
3830 size_t relnum,
3831 Output_segment* tls_segment,
3832 const elfcpp::Rela<size, false>& rela,
3833 unsigned int,
3834 typename elfcpp::Elf_types<size>::Elf_Addr value,
3835 unsigned char* view,
3836 section_size_type view_size)
3837 {
3838 // For SIZE == 64:
3839 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3840 // .word 0x6666; rex64; call __tls_get_addr
3841 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
3842 // For SIZE == 32:
3843 // leaq foo@tlsgd(%rip),%rdi;
3844 // .word 0x6666; rex64; call __tls_get_addr
3845 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
3846
3847 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3848 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3849 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3850
3851 if (size == 64)
3852 {
3853 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3854 -4);
3855 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3856 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3857 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
3858 16);
3859 }
3860 else
3861 {
3862 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3863 -3);
3864 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3865 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
3866
3867 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
3868 15);
3869 }
3870
3871 value -= tls_segment->memsz();
3872 Relocate_functions<size, false>::rela32(view + 8, value, 0);
3873
3874 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3875 // We can skip it.
3876 this->skip_call_tls_get_addr_ = true;
3877 }
3878
3879 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
3880
3881 template<int size>
3882 inline void
3883 Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
3884 const Relocate_info<size, false>* relinfo,
3885 size_t relnum,
3886 Output_segment*,
3887 const elfcpp::Rela<size, false>& rela,
3888 unsigned int r_type,
3889 typename elfcpp::Elf_types<size>::Elf_Addr value,
3890 unsigned char* view,
3891 typename elfcpp::Elf_types<size>::Elf_Addr address,
3892 section_size_type view_size)
3893 {
3894 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3895 {
3896 // leaq foo@tlsdesc(%rip), %rax
3897 // ==> movq foo@gottpoff(%rip), %rax
3898 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3899 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3900 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3901 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3902 view[-2] = 0x8b;
3903 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3904 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3905 }
3906 else
3907 {
3908 // call *foo@tlscall(%rax)
3909 // ==> nop; nop
3910 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3911 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3912 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3913 view[0] == 0xff && view[1] == 0x10);
3914 view[0] = 0x66;
3915 view[1] = 0x90;
3916 }
3917 }
3918
3919 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
3920
3921 template<int size>
3922 inline void
3923 Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
3924 const Relocate_info<size, false>* relinfo,
3925 size_t relnum,
3926 Output_segment* tls_segment,
3927 const elfcpp::Rela<size, false>& rela,
3928 unsigned int r_type,
3929 typename elfcpp::Elf_types<size>::Elf_Addr value,
3930 unsigned char* view,
3931 section_size_type view_size)
3932 {
3933 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3934 {
3935 // leaq foo@tlsdesc(%rip), %rax
3936 // ==> movq foo@tpoff, %rax
3937 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3938 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3939 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3940 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3941 view[-2] = 0xc7;
3942 view[-1] = 0xc0;
3943 value -= tls_segment->memsz();
3944 Relocate_functions<size, false>::rela32(view, value, 0);
3945 }
3946 else
3947 {
3948 // call *foo@tlscall(%rax)
3949 // ==> nop; nop
3950 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3951 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3952 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3953 view[0] == 0xff && view[1] == 0x10);
3954 view[0] = 0x66;
3955 view[1] = 0x90;
3956 }
3957 }
3958
3959 template<int size>
3960 inline void
3961 Target_x86_64<size>::Relocate::tls_ld_to_le(
3962 const Relocate_info<size, false>* relinfo,
3963 size_t relnum,
3964 Output_segment*,
3965 const elfcpp::Rela<size, false>& rela,
3966 unsigned int,
3967 typename elfcpp::Elf_types<size>::Elf_Addr,
3968 unsigned char* view,
3969 section_size_type view_size)
3970 {
3971 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
3972 // For SIZE == 64:
3973 // ... leq foo@dtpoff(%rax),%reg
3974 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
3975 // For SIZE == 32:
3976 // ... leq foo@dtpoff(%rax),%reg
3977 // ==> nopl 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx
3978
3979 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3980 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
3981
3982 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3983 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
3984
3985 tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
3986
3987 if (size == 64)
3988 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
3989 else
3990 memcpy(view - 3, "\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 12);
3991
3992 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3993 // We can skip it.
3994 this->skip_call_tls_get_addr_ = true;
3995 }
3996
3997 // Do a relocation in which we convert a TLS Initial-Exec to a
3998 // Local-Exec.
3999
4000 template<int size>
4001 inline void
4002 Target_x86_64<size>::Relocate::tls_ie_to_le(
4003 const Relocate_info<size, false>* relinfo,
4004 size_t relnum,
4005 Output_segment* tls_segment,
4006 const elfcpp::Rela<size, false>& rela,
4007 unsigned int,
4008 typename elfcpp::Elf_types<size>::Elf_Addr value,
4009 unsigned char* view,
4010 section_size_type view_size)
4011 {
4012 // We need to examine the opcodes to figure out which instruction we
4013 // are looking at.
4014
4015 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
4016 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
4017
4018 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
4019 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
4020
4021 unsigned char op1 = view[-3];
4022 unsigned char op2 = view[-2];
4023 unsigned char op3 = view[-1];
4024 unsigned char reg = op3 >> 3;
4025
4026 if (op2 == 0x8b)
4027 {
4028 // movq
4029 if (op1 == 0x4c)
4030 view[-3] = 0x49;
4031 view[-2] = 0xc7;
4032 view[-1] = 0xc0 | reg;
4033 }
4034 else if (reg == 4)
4035 {
4036 // Special handling for %rsp.
4037 if (op1 == 0x4c)
4038 view[-3] = 0x49;
4039 view[-2] = 0x81;
4040 view[-1] = 0xc0 | reg;
4041 }
4042 else
4043 {
4044 // addq
4045 if (op1 == 0x4c)
4046 view[-3] = 0x4d;
4047 view[-2] = 0x8d;
4048 view[-1] = 0x80 | reg | (reg << 3);
4049 }
4050
4051 value -= tls_segment->memsz();
4052 Relocate_functions<size, false>::rela32(view, value, 0);
4053 }
4054
4055 // Relocate section data.
4056
4057 template<int size>
4058 void
4059 Target_x86_64<size>::relocate_section(
4060 const Relocate_info<size, false>* relinfo,
4061 unsigned int sh_type,
4062 const unsigned char* prelocs,
4063 size_t reloc_count,
4064 Output_section* output_section,
4065 bool needs_special_offset_handling,
4066 unsigned char* view,
4067 typename elfcpp::Elf_types<size>::Elf_Addr address,
4068 section_size_type view_size,
4069 const Reloc_symbol_changes* reloc_symbol_changes)
4070 {
4071 gold_assert(sh_type == elfcpp::SHT_RELA);
4072
4073 gold::relocate_section<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
4074 typename Target_x86_64<size>::Relocate,
4075 gold::Default_comdat_behavior>(
4076 relinfo,
4077 this,
4078 prelocs,
4079 reloc_count,
4080 output_section,
4081 needs_special_offset_handling,
4082 view,
4083 address,
4084 view_size,
4085 reloc_symbol_changes);
4086 }
4087
4088 // Apply an incremental relocation. Incremental relocations always refer
4089 // to global symbols.
4090
4091 template<int size>
4092 void
4093 Target_x86_64<size>::apply_relocation(
4094 const Relocate_info<size, false>* relinfo,
4095 typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
4096 unsigned int r_type,
4097 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
4098 const Symbol* gsym,
4099 unsigned char* view,
4100 typename elfcpp::Elf_types<size>::Elf_Addr address,
4101 section_size_type view_size)
4102 {
4103 gold::apply_relocation<size, false, Target_x86_64<size>,
4104 typename Target_x86_64<size>::Relocate>(
4105 relinfo,
4106 this,
4107 r_offset,
4108 r_type,
4109 r_addend,
4110 gsym,
4111 view,
4112 address,
4113 view_size);
4114 }
4115
4116 // Return the size of a relocation while scanning during a relocatable
4117 // link.
4118
4119 template<int size>
4120 unsigned int
4121 Target_x86_64<size>::Relocatable_size_for_reloc::get_size_for_reloc(
4122 unsigned int r_type,
4123 Relobj* object)
4124 {
4125 switch (r_type)
4126 {
4127 case elfcpp::R_X86_64_NONE:
4128 case elfcpp::R_X86_64_GNU_VTINHERIT:
4129 case elfcpp::R_X86_64_GNU_VTENTRY:
4130 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
4131 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
4132 case elfcpp::R_X86_64_TLSDESC_CALL:
4133 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
4134 case elfcpp::R_X86_64_DTPOFF32:
4135 case elfcpp::R_X86_64_DTPOFF64:
4136 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
4137 case elfcpp::R_X86_64_TPOFF32: // Local-exec
4138 return 0;
4139
4140 case elfcpp::R_X86_64_64:
4141 case elfcpp::R_X86_64_PC64:
4142 case elfcpp::R_X86_64_GOTOFF64:
4143 case elfcpp::R_X86_64_GOTPC64:
4144 case elfcpp::R_X86_64_PLTOFF64:
4145 case elfcpp::R_X86_64_GOT64:
4146 case elfcpp::R_X86_64_GOTPCREL64:
4147 case elfcpp::R_X86_64_GOTPCREL:
4148 case elfcpp::R_X86_64_GOTPLT64:
4149 return 8;
4150
4151 case elfcpp::R_X86_64_32:
4152 case elfcpp::R_X86_64_32S:
4153 case elfcpp::R_X86_64_PC32:
4154 case elfcpp::R_X86_64_PLT32:
4155 case elfcpp::R_X86_64_GOTPC32:
4156 case elfcpp::R_X86_64_GOT32:
4157 return 4;
4158
4159 case elfcpp::R_X86_64_16:
4160 case elfcpp::R_X86_64_PC16:
4161 return 2;
4162
4163 case elfcpp::R_X86_64_8:
4164 case elfcpp::R_X86_64_PC8:
4165 return 1;
4166
4167 case elfcpp::R_X86_64_COPY:
4168 case elfcpp::R_X86_64_GLOB_DAT:
4169 case elfcpp::R_X86_64_JUMP_SLOT:
4170 case elfcpp::R_X86_64_RELATIVE:
4171 case elfcpp::R_X86_64_IRELATIVE:
4172 // These are outstanding tls relocs, which are unexpected when linking
4173 case elfcpp::R_X86_64_TPOFF64:
4174 case elfcpp::R_X86_64_DTPMOD64:
4175 case elfcpp::R_X86_64_TLSDESC:
4176 object->error(_("unexpected reloc %u in object file"), r_type);
4177 return 0;
4178
4179 case elfcpp::R_X86_64_SIZE32:
4180 case elfcpp::R_X86_64_SIZE64:
4181 default:
4182 object->error(_("unsupported reloc %u against local symbol"), r_type);
4183 return 0;
4184 }
4185 }
4186
4187 // Scan the relocs during a relocatable link.
4188
4189 template<int size>
4190 void
4191 Target_x86_64<size>::scan_relocatable_relocs(
4192 Symbol_table* symtab,
4193 Layout* layout,
4194 Sized_relobj_file<size, false>* object,
4195 unsigned int data_shndx,
4196 unsigned int sh_type,
4197 const unsigned char* prelocs,
4198 size_t reloc_count,
4199 Output_section* output_section,
4200 bool needs_special_offset_handling,
4201 size_t local_symbol_count,
4202 const unsigned char* plocal_symbols,
4203 Relocatable_relocs* rr)
4204 {
4205 gold_assert(sh_type == elfcpp::SHT_RELA);
4206
4207 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
4208 Relocatable_size_for_reloc> Scan_relocatable_relocs;
4209
4210 gold::scan_relocatable_relocs<size, false, elfcpp::SHT_RELA,
4211 Scan_relocatable_relocs>(
4212 symtab,
4213 layout,
4214 object,
4215 data_shndx,
4216 prelocs,
4217 reloc_count,
4218 output_section,
4219 needs_special_offset_handling,
4220 local_symbol_count,
4221 plocal_symbols,
4222 rr);
4223 }
4224
4225 // Relocate a section during a relocatable link.
4226
4227 template<int size>
4228 void
4229 Target_x86_64<size>::relocate_relocs(
4230 const Relocate_info<size, false>* relinfo,
4231 unsigned int sh_type,
4232 const unsigned char* prelocs,
4233 size_t reloc_count,
4234 Output_section* output_section,
4235 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
4236 const Relocatable_relocs* rr,
4237 unsigned char* view,
4238 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
4239 section_size_type view_size,
4240 unsigned char* reloc_view,
4241 section_size_type reloc_view_size)
4242 {
4243 gold_assert(sh_type == elfcpp::SHT_RELA);
4244
4245 gold::relocate_relocs<size, false, elfcpp::SHT_RELA>(
4246 relinfo,
4247 prelocs,
4248 reloc_count,
4249 output_section,
4250 offset_in_output_section,
4251 rr,
4252 view,
4253 view_address,
4254 view_size,
4255 reloc_view,
4256 reloc_view_size);
4257 }
4258
4259 // Return the value to use for a dynamic which requires special
4260 // treatment. This is how we support equality comparisons of function
4261 // pointers across shared library boundaries, as described in the
4262 // processor specific ABI supplement.
4263
4264 template<int size>
4265 uint64_t
4266 Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const
4267 {
4268 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
4269 return this->plt_address_for_global(gsym);
4270 }
4271
4272 // Return a string used to fill a code section with nops to take up
4273 // the specified length.
4274
4275 template<int size>
4276 std::string
4277 Target_x86_64<size>::do_code_fill(section_size_type length) const
4278 {
4279 if (length >= 16)
4280 {
4281 // Build a jmpq instruction to skip over the bytes.
4282 unsigned char jmp[5];
4283 jmp[0] = 0xe9;
4284 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
4285 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
4286 + std::string(length - 5, static_cast<char>(0x90)));
4287 }
4288
4289 // Nop sequences of various lengths.
4290 const char nop1[1] = { '\x90' }; // nop
4291 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
4292 const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax)
4293 const char nop4[4] = { '\x0f', '\x1f', '\x40', // nop 0(%rax)
4294 '\x00'};
4295 const char nop5[5] = { '\x0f', '\x1f', '\x44', // nop 0(%rax,%rax,1)
4296 '\x00', '\x00' };
4297 const char nop6[6] = { '\x66', '\x0f', '\x1f', // nopw 0(%rax,%rax,1)
4298 '\x44', '\x00', '\x00' };
4299 const char nop7[7] = { '\x0f', '\x1f', '\x80', // nopl 0L(%rax)
4300 '\x00', '\x00', '\x00',
4301 '\x00' };
4302 const char nop8[8] = { '\x0f', '\x1f', '\x84', // nopl 0L(%rax,%rax,1)
4303 '\x00', '\x00', '\x00',
4304 '\x00', '\x00' };
4305 const char nop9[9] = { '\x66', '\x0f', '\x1f', // nopw 0L(%rax,%rax,1)
4306 '\x84', '\x00', '\x00',
4307 '\x00', '\x00', '\x00' };
4308 const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
4309 '\x1f', '\x84', '\x00',
4310 '\x00', '\x00', '\x00',
4311 '\x00' };
4312 const char nop11[11] = { '\x66', '\x66', '\x2e', // data16
4313 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
4314 '\x00', '\x00', '\x00',
4315 '\x00', '\x00' };
4316 const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16
4317 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
4318 '\x84', '\x00', '\x00',
4319 '\x00', '\x00', '\x00' };
4320 const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16
4321 '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
4322 '\x1f', '\x84', '\x00',
4323 '\x00', '\x00', '\x00',
4324 '\x00' };
4325 const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16
4326 '\x66', '\x66', '\x2e', // data16
4327 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
4328 '\x00', '\x00', '\x00',
4329 '\x00', '\x00' };
4330 const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16
4331 '\x66', '\x66', '\x66', // data16; data16
4332 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
4333 '\x84', '\x00', '\x00',
4334 '\x00', '\x00', '\x00' };
4335
4336 const char* nops[16] = {
4337 NULL,
4338 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
4339 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
4340 };
4341
4342 return std::string(nops[length], length);
4343 }
4344
4345 // Return the addend to use for a target specific relocation. The
4346 // only target specific relocation is R_X86_64_TLSDESC for a local
4347 // symbol. We want to set the addend is the offset of the local
4348 // symbol in the TLS segment.
4349
4350 template<int size>
4351 uint64_t
4352 Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type,
4353 uint64_t) const
4354 {
4355 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
4356 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
4357 gold_assert(intarg < this->tlsdesc_reloc_info_.size());
4358 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
4359 const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym);
4360 gold_assert(psymval->is_tls_symbol());
4361 // The value of a TLS symbol is the offset in the TLS segment.
4362 return psymval->value(ti.object, 0);
4363 }
4364
4365 // Return the value to use for the base of a DW_EH_PE_datarel offset
4366 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
4367 // assembler can not write out the difference between two labels in
4368 // different sections, so instead of using a pc-relative value they
4369 // use an offset from the GOT.
4370
4371 template<int size>
4372 uint64_t
4373 Target_x86_64<size>::do_ehframe_datarel_base() const
4374 {
4375 gold_assert(this->global_offset_table_ != NULL);
4376 Symbol* sym = this->global_offset_table_;
4377 Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym);
4378 return ssym->value();
4379 }
4380
4381 // FNOFFSET in section SHNDX in OBJECT is the start of a function
4382 // compiled with -fsplit-stack. The function calls non-split-stack
4383 // code. We have to change the function so that it always ensures
4384 // that it has enough stack space to run some random function.
4385
4386 template<int size>
4387 void
4388 Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx,
4389 section_offset_type fnoffset,
4390 section_size_type fnsize,
4391 unsigned char* view,
4392 section_size_type view_size,
4393 std::string* from,
4394 std::string* to) const
4395 {
4396 // The function starts with a comparison of the stack pointer and a
4397 // field in the TCB. This is followed by a jump.
4398
4399 // cmp %fs:NN,%rsp
4400 if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
4401 && fnsize > 9)
4402 {
4403 // We will call __morestack if the carry flag is set after this
4404 // comparison. We turn the comparison into an stc instruction
4405 // and some nops.
4406 view[fnoffset] = '\xf9';
4407 this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
4408 }
4409 // lea NN(%rsp),%r10
4410 // lea NN(%rsp),%r11
4411 else if ((this->match_view(view, view_size, fnoffset,
4412 "\x4c\x8d\x94\x24", 4)
4413 || this->match_view(view, view_size, fnoffset,
4414 "\x4c\x8d\x9c\x24", 4))
4415 && fnsize > 8)
4416 {
4417 // This is loading an offset from the stack pointer for a
4418 // comparison. The offset is negative, so we decrease the
4419 // offset by the amount of space we need for the stack. This
4420 // means we will avoid calling __morestack if there happens to
4421 // be plenty of space on the stack already.
4422 unsigned char* pval = view + fnoffset + 4;
4423 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
4424 val -= parameters->options().split_stack_adjust_size();
4425 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
4426 }
4427 else
4428 {
4429 if (!object->has_no_split_stack())
4430 object->error(_("failed to match split-stack sequence at "
4431 "section %u offset %0zx"),
4432 shndx, static_cast<size_t>(fnoffset));
4433 return;
4434 }
4435
4436 // We have to change the function so that it calls
4437 // __morestack_non_split instead of __morestack. The former will
4438 // allocate additional stack space.
4439 *from = "__morestack";
4440 *to = "__morestack_non_split";
4441 }
4442
4443 // The selector for x86_64 object files. Note this is never instantiated
4444 // directly. It's only used in Target_selector_x86_64_nacl, below.
4445
4446 template<int size>
4447 class Target_selector_x86_64 : public Target_selector_freebsd
4448 {
4449 public:
4450 Target_selector_x86_64()
4451 : Target_selector_freebsd(elfcpp::EM_X86_64, size, false,
4452 (size == 64
4453 ? "elf64-x86-64" : "elf32-x86-64"),
4454 (size == 64
4455 ? "elf64-x86-64-freebsd"
4456 : "elf32-x86-64-freebsd"),
4457 (size == 64 ? "elf_x86_64" : "elf32_x86_64"))
4458 { }
4459
4460 Target*
4461 do_instantiate_target()
4462 { return new Target_x86_64<size>(); }
4463
4464 };
4465
4466 // NaCl variant. It uses different PLT contents.
4467
4468 template<int size>
4469 class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size>
4470 {
4471 public:
4472 Output_data_plt_x86_64_nacl(Layout* layout,
4473 Output_data_got<64, false>* got,
4474 Output_data_space* got_plt,
4475 Output_data_space* got_irelative)
4476 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
4477 got, got_plt, got_irelative)
4478 { }
4479
4480 Output_data_plt_x86_64_nacl(Layout* layout,
4481 Output_data_got<64, false>* got,
4482 Output_data_space* got_plt,
4483 Output_data_space* got_irelative,
4484 unsigned int plt_count)
4485 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
4486 got, got_plt, got_irelative,
4487 plt_count)
4488 { }
4489
4490 protected:
4491 virtual unsigned int
4492 do_get_plt_entry_size() const
4493 { return plt_entry_size; }
4494
4495 virtual void
4496 do_add_eh_frame(Layout* layout)
4497 {
4498 layout->add_eh_frame_for_plt(this,
4499 this->plt_eh_frame_cie,
4500 this->plt_eh_frame_cie_size,
4501 plt_eh_frame_fde,
4502 plt_eh_frame_fde_size);
4503 }
4504
4505 virtual void
4506 do_fill_first_plt_entry(unsigned char* pov,
4507 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
4508 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr);
4509
4510 virtual unsigned int
4511 do_fill_plt_entry(unsigned char* pov,
4512 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
4513 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
4514 unsigned int got_offset,
4515 unsigned int plt_offset,
4516 unsigned int plt_index);
4517
4518 virtual void
4519 do_fill_tlsdesc_entry(unsigned char* pov,
4520 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
4521 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
4522 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
4523 unsigned int tlsdesc_got_offset,
4524 unsigned int plt_offset);
4525
4526 private:
4527 // The size of an entry in the PLT.
4528 static const int plt_entry_size = 64;
4529
4530 // The first entry in the PLT.
4531 static const unsigned char first_plt_entry[plt_entry_size];
4532
4533 // Other entries in the PLT for an executable.
4534 static const unsigned char plt_entry[plt_entry_size];
4535
4536 // The reserved TLSDESC entry in the PLT for an executable.
4537 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
4538
4539 // The .eh_frame unwind information for the PLT.
4540 static const int plt_eh_frame_fde_size = 32;
4541 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
4542 };
4543
4544 template<int size>
4545 class Target_x86_64_nacl : public Target_x86_64<size>
4546 {
4547 public:
4548 Target_x86_64_nacl()
4549 : Target_x86_64<size>(&x86_64_nacl_info)
4550 { }
4551
4552 virtual Output_data_plt_x86_64<size>*
4553 do_make_data_plt(Layout* layout,
4554 Output_data_got<64, false>* got,
4555 Output_data_space* got_plt,
4556 Output_data_space* got_irelative)
4557 {
4558 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
4559 got_irelative);
4560 }
4561
4562 virtual Output_data_plt_x86_64<size>*
4563 do_make_data_plt(Layout* layout,
4564 Output_data_got<64, false>* got,
4565 Output_data_space* got_plt,
4566 Output_data_space* got_irelative,
4567 unsigned int plt_count)
4568 {
4569 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
4570 got_irelative,
4571 plt_count);
4572 }
4573
4574 virtual std::string
4575 do_code_fill(section_size_type length) const;
4576
4577 private:
4578 static const Target::Target_info x86_64_nacl_info;
4579 };
4580
4581 template<>
4582 const Target::Target_info Target_x86_64_nacl<64>::x86_64_nacl_info =
4583 {
4584 64, // size
4585 false, // is_big_endian
4586 elfcpp::EM_X86_64, // machine_code
4587 false, // has_make_symbol
4588 false, // has_resolve
4589 true, // has_code_fill
4590 true, // is_default_stack_executable
4591 true, // can_icf_inline_merge_sections
4592 '\0', // wrap_char
4593 "/lib64/ld-nacl-x86-64.so.1", // dynamic_linker
4594 0x20000, // default_text_segment_address
4595 0x10000, // abi_pagesize (overridable by -z max-page-size)
4596 0x10000, // common_pagesize (overridable by -z common-page-size)
4597 true, // isolate_execinstr
4598 0x10000000, // rosegment_gap
4599 elfcpp::SHN_UNDEF, // small_common_shndx
4600 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
4601 0, // small_common_section_flags
4602 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
4603 NULL, // attributes_section
4604 NULL, // attributes_vendor
4605 "_start" // entry_symbol_name
4606 };
4607
4608 template<>
4609 const Target::Target_info Target_x86_64_nacl<32>::x86_64_nacl_info =
4610 {
4611 32, // size
4612 false, // is_big_endian
4613 elfcpp::EM_X86_64, // machine_code
4614 false, // has_make_symbol
4615 false, // has_resolve
4616 true, // has_code_fill
4617 true, // is_default_stack_executable
4618 true, // can_icf_inline_merge_sections
4619 '\0', // wrap_char
4620 "/lib/ld-nacl-x86-64.so.1", // dynamic_linker
4621 0x20000, // default_text_segment_address
4622 0x10000, // abi_pagesize (overridable by -z max-page-size)
4623 0x10000, // common_pagesize (overridable by -z common-page-size)
4624 true, // isolate_execinstr
4625 0x10000000, // rosegment_gap
4626 elfcpp::SHN_UNDEF, // small_common_shndx
4627 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
4628 0, // small_common_section_flags
4629 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
4630 NULL, // attributes_section
4631 NULL, // attributes_vendor
4632 "_start" // entry_symbol_name
4633 };
4634
4635 #define NACLMASK 0xe0 // 32-byte alignment mask.
4636
4637 // The first entry in the PLT.
4638
4639 template<int size>
4640 const unsigned char
4641 Output_data_plt_x86_64_nacl<size>::first_plt_entry[plt_entry_size] =
4642 {
4643 0xff, 0x35, // pushq contents of memory address
4644 0, 0, 0, 0, // replaced with address of .got + 8
4645 0x4c, 0x8b, 0x1d, // mov GOT+16(%rip), %r11
4646 0, 0, 0, 0, // replaced with address of .got + 16
4647 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
4648 0x4d, 0x01, 0xfb, // add %r15, %r11
4649 0x41, 0xff, 0xe3, // jmpq *%r11
4650
4651 // 9-byte nop sequence to pad out to the next 32-byte boundary.
4652 0x66, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw 0x0(%rax,%rax,1)
4653
4654 // 32 bytes of nop to pad out to the standard size
4655 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4656 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4657 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4658 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4659 0x66, // excess data32 prefix
4660 0x90 // nop
4661 };
4662
4663 template<int size>
4664 void
4665 Output_data_plt_x86_64_nacl<size>::do_fill_first_plt_entry(
4666 unsigned char* pov,
4667 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
4668 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
4669 {
4670 memcpy(pov, first_plt_entry, plt_entry_size);
4671 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4672 (got_address + 8
4673 - (plt_address + 2 + 4)));
4674 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
4675 (got_address + 16
4676 - (plt_address + 9 + 4)));
4677 }
4678
4679 // Subsequent entries in the PLT.
4680
4681 template<int size>
4682 const unsigned char
4683 Output_data_plt_x86_64_nacl<size>::plt_entry[plt_entry_size] =
4684 {
4685 0x4c, 0x8b, 0x1d, // mov name@GOTPCREL(%rip),%r11
4686 0, 0, 0, 0, // replaced with address of symbol in .got
4687 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
4688 0x4d, 0x01, 0xfb, // add %r15, %r11
4689 0x41, 0xff, 0xe3, // jmpq *%r11
4690
4691 // 15-byte nop sequence to pad out to the next 32-byte boundary.
4692 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4693 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4694
4695 // Lazy GOT entries point here (32-byte aligned).
4696 0x68, // pushq immediate
4697 0, 0, 0, 0, // replaced with index into relocation table
4698 0xe9, // jmp relative
4699 0, 0, 0, 0, // replaced with offset to start of .plt0
4700
4701 // 22 bytes of nop to pad out to the standard size.
4702 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4703 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4704 0x0f, 0x1f, 0x80, 0, 0, 0, 0, // nopl 0x0(%rax)
4705 };
4706
4707 template<int size>
4708 unsigned int
4709 Output_data_plt_x86_64_nacl<size>::do_fill_plt_entry(
4710 unsigned char* pov,
4711 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
4712 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
4713 unsigned int got_offset,
4714 unsigned int plt_offset,
4715 unsigned int plt_index)
4716 {
4717 memcpy(pov, plt_entry, plt_entry_size);
4718 elfcpp::Swap_unaligned<32, false>::writeval(pov + 3,
4719 (got_address + got_offset
4720 - (plt_address + plt_offset
4721 + 3 + 4)));
4722
4723 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_index);
4724 elfcpp::Swap_unaligned<32, false>::writeval(pov + 38,
4725 - (plt_offset + 38 + 4));
4726
4727 return 32;
4728 }
4729
4730 // The reserved TLSDESC entry in the PLT.
4731
4732 template<int size>
4733 const unsigned char
4734 Output_data_plt_x86_64_nacl<size>::tlsdesc_plt_entry[plt_entry_size] =
4735 {
4736 0xff, 0x35, // pushq x(%rip)
4737 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
4738 0x4c, 0x8b, 0x1d, // mov y(%rip),%r11
4739 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
4740 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
4741 0x4d, 0x01, 0xfb, // add %r15, %r11
4742 0x41, 0xff, 0xe3, // jmpq *%r11
4743
4744 // 41 bytes of nop to pad out to the standard size.
4745 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4746 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4747 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
4748 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4749 0x66, 0x66, // excess data32 prefixes
4750 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
4751 };
4752
4753 template<int size>
4754 void
4755 Output_data_plt_x86_64_nacl<size>::do_fill_tlsdesc_entry(
4756 unsigned char* pov,
4757 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
4758 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
4759 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
4760 unsigned int tlsdesc_got_offset,
4761 unsigned int plt_offset)
4762 {
4763 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
4764 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4765 (got_address + 8
4766 - (plt_address + plt_offset
4767 + 2 + 4)));
4768 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
4769 (got_base
4770 + tlsdesc_got_offset
4771 - (plt_address + plt_offset
4772 + 9 + 4)));
4773 }
4774
4775 // The .eh_frame unwind information for the PLT.
4776
4777 template<int size>
4778 const unsigned char
4779 Output_data_plt_x86_64_nacl<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
4780 {
4781 0, 0, 0, 0, // Replaced with offset to .plt.
4782 0, 0, 0, 0, // Replaced with size of .plt.
4783 0, // Augmentation size.
4784 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
4785 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
4786 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
4787 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
4788 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
4789 13, // Block length.
4790 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
4791 elfcpp::DW_OP_breg16, 0, // Push %rip.
4792 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
4793 elfcpp::DW_OP_and, // & (%rip & 0x3f).
4794 elfcpp::DW_OP_const1u, 37, // Push 0x25.
4795 elfcpp::DW_OP_ge, // >= ((%rip & 0x3f) >= 0x25)
4796 elfcpp::DW_OP_lit3, // Push 3.
4797 elfcpp::DW_OP_shl, // << (((%rip & 0x3f) >= 0x25) << 3)
4798 elfcpp::DW_OP_plus, // + ((((%rip&0x3f)>=0x25)<<3)+%rsp+8
4799 elfcpp::DW_CFA_nop, // Align to 32 bytes.
4800 elfcpp::DW_CFA_nop
4801 };
4802
4803 // Return a string used to fill a code section with nops.
4804 // For NaCl, long NOPs are only valid if they do not cross
4805 // bundle alignment boundaries, so keep it simple with one-byte NOPs.
4806 template<int size>
4807 std::string
4808 Target_x86_64_nacl<size>::do_code_fill(section_size_type length) const
4809 {
4810 return std::string(length, static_cast<char>(0x90));
4811 }
4812
4813 // The selector for x86_64-nacl object files.
4814
4815 template<int size>
4816 class Target_selector_x86_64_nacl
4817 : public Target_selector_nacl<Target_selector_x86_64<size>,
4818 Target_x86_64_nacl<size> >
4819 {
4820 public:
4821 Target_selector_x86_64_nacl()
4822 : Target_selector_nacl<Target_selector_x86_64<size>,
4823 Target_x86_64_nacl<size> >("x86-64",
4824 size == 64
4825 ? "elf64-x86-64-nacl"
4826 : "elf32-x86-64-nacl",
4827 size == 64
4828 ? "elf_x86_64_nacl"
4829 : "elf32_x86_64_nacl")
4830 { }
4831 };
4832
4833 Target_selector_x86_64_nacl<64> target_selector_x86_64;
4834 Target_selector_x86_64_nacl<32> target_selector_x32;
4835
4836 } // End anonymous namespace.
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