Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.24 / gold / x86_64.cc
CommitLineData
f40e693d
JM
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
47namespace
48{
49
50using 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
57template<int size>
58class 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
301template<int size>
302class 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
386template<int size>
387class 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
985template<>
986const 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
1012template<>
1013const 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
1042template<int size>
1043void
1044Target_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
1052template<int size>
1053Output_data_got<64, false>*
1054Target_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
1128template<int size>
1129typename Target_x86_64<size>::Reloc_section*
1130Target_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
1149template<int size>
1150typename Target_x86_64<size>::Reloc_section*
1151Target_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
1169template<int size>
1170void
1171Output_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
1179template<int size>
1180void
1181Output_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
1188template<int size>
1189void
1190Output_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
1267template<int size>
1268unsigned int
1269Output_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
1295template<int size>
1296void
1297Output_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
1320template<int size>
1321typename Output_data_plt_x86_64<size>::Reloc_section*
1322Output_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
1339template<int size>
1340typename Output_data_plt_x86_64<size>::Reloc_section*
1341Output_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
1380template<int size>
1381uint64_t
1382Output_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
1394template<int size>
1395uint64_t
1396Output_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.
1405template<int size>
1406void
1407Output_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
1417template<int size>
1418const unsigned char
1419Output_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
1429template<int size>
1430void
1431Output_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
1448template<int size>
1449const unsigned char
1450Output_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
1461template<int size>
1462unsigned int
1463Output_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
1486template<int size>
1487const unsigned char
1488Output_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
1500template<int size>
1501void
1502Output_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
1524template<int size>
1525const unsigned char
1526Output_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
1544template<int size>
1545const unsigned char
1546Output_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
1575template<int size>
1576void
1577Output_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
1662template<int size>
1663void
1664Target_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
1691template<int size>
1692typename Target_x86_64<size>::Reloc_section*
1693Target_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
1700template<int size>
1701void
1702Target_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
1716template<int size>
1717void
1718Target_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
1735template<int size>
1736unsigned int
1737Target_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
1746template<int size>
1747unsigned int
1748Target_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
1755template<int size>
1756unsigned int
1757Target_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
1764template<int size>
1765Output_data_got_base*
1766Target_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
1842template<int size>
1843void
1844Target_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
1884template<int size>
1885void
1886Target_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
1933template<int size>
1934void
1935Target_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
1953template<int size>
1954void
1955Target_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
1967template<int size>
1968void
1969Target_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
1995template<int size>
1996void
1997Target_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
2016template<int size>
2017unsigned int
2018Target_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
2039template<int size>
2040tls::Tls_optimization
2041Target_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
2093template<int size>
2094int
2095Target_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_PC32_BND:
2117 case elfcpp::R_X86_64_PC16:
2118 case elfcpp::R_X86_64_PC8:
2119 case elfcpp::R_X86_64_GOTOFF64:
2120 return Symbol::RELATIVE_REF;
2121
2122 case elfcpp::R_X86_64_PLT32:
2123 case elfcpp::R_X86_64_PLT32_BND:
2124 case elfcpp::R_X86_64_PLTOFF64:
2125 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
2126
2127 case elfcpp::R_X86_64_GOT64:
2128 case elfcpp::R_X86_64_GOT32:
2129 case elfcpp::R_X86_64_GOTPCREL64:
2130 case elfcpp::R_X86_64_GOTPCREL:
2131 case elfcpp::R_X86_64_GOTPLT64:
2132 // Absolute in GOT.
2133 return Symbol::ABSOLUTE_REF;
2134
2135 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2136 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2137 case elfcpp::R_X86_64_TLSDESC_CALL:
2138 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2139 case elfcpp::R_X86_64_DTPOFF32:
2140 case elfcpp::R_X86_64_DTPOFF64:
2141 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2142 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2143 return Symbol::TLS_REF;
2144
2145 case elfcpp::R_X86_64_COPY:
2146 case elfcpp::R_X86_64_GLOB_DAT:
2147 case elfcpp::R_X86_64_JUMP_SLOT:
2148 case elfcpp::R_X86_64_RELATIVE:
2149 case elfcpp::R_X86_64_IRELATIVE:
2150 case elfcpp::R_X86_64_TPOFF64:
2151 case elfcpp::R_X86_64_DTPMOD64:
2152 case elfcpp::R_X86_64_TLSDESC:
2153 case elfcpp::R_X86_64_SIZE32:
2154 case elfcpp::R_X86_64_SIZE64:
2155 default:
2156 // Not expected. We will give an error later.
2157 return 0;
2158 }
2159}
2160
2161// Report an unsupported relocation against a local symbol.
2162
2163template<int size>
2164void
2165Target_x86_64<size>::Scan::unsupported_reloc_local(
2166 Sized_relobj_file<size, false>* object,
2167 unsigned int r_type)
2168{
2169 gold_error(_("%s: unsupported reloc %u against local symbol"),
2170 object->name().c_str(), r_type);
2171}
2172
2173// We are about to emit a dynamic relocation of type R_TYPE. If the
2174// dynamic linker does not support it, issue an error. The GNU linker
2175// only issues a non-PIC error for an allocated read-only section.
2176// Here we know the section is allocated, but we don't know that it is
2177// read-only. But we check for all the relocation types which the
2178// glibc dynamic linker supports, so it seems appropriate to issue an
2179// error even if the section is not read-only. If GSYM is not NULL,
2180// it is the symbol the relocation is against; if it is NULL, the
2181// relocation is against a local symbol.
2182
2183template<int size>
2184void
2185Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type,
2186 Symbol* gsym)
2187{
2188 switch (r_type)
2189 {
2190 // These are the relocation types supported by glibc for x86_64
2191 // which should always work.
2192 case elfcpp::R_X86_64_RELATIVE:
2193 case elfcpp::R_X86_64_IRELATIVE:
2194 case elfcpp::R_X86_64_GLOB_DAT:
2195 case elfcpp::R_X86_64_JUMP_SLOT:
2196 case elfcpp::R_X86_64_DTPMOD64:
2197 case elfcpp::R_X86_64_DTPOFF64:
2198 case elfcpp::R_X86_64_TPOFF64:
2199 case elfcpp::R_X86_64_64:
2200 case elfcpp::R_X86_64_COPY:
2201 return;
2202
2203 // glibc supports these reloc types, but they can overflow.
2204 case elfcpp::R_X86_64_PC32:
2205 case elfcpp::R_X86_64_PC32_BND:
2206 // A PC relative reference is OK against a local symbol or if
2207 // the symbol is defined locally.
2208 if (gsym == NULL
2209 || (!gsym->is_from_dynobj()
2210 && !gsym->is_undefined()
2211 && !gsym->is_preemptible()))
2212 return;
2213 /* Fall through. */
2214 case elfcpp::R_X86_64_32:
2215 // R_X86_64_32 is OK for x32.
2216 if (size == 32 && r_type == elfcpp::R_X86_64_32)
2217 return;
2218 if (this->issued_non_pic_error_)
2219 return;
2220 gold_assert(parameters->options().output_is_position_independent());
2221 if (gsym == NULL)
2222 object->error(_("requires dynamic R_X86_64_32 reloc which may "
2223 "overflow at runtime; recompile with -fPIC"));
2224 else
2225 {
2226 const char *r_name;
2227 switch (r_type)
2228 {
2229 case elfcpp::R_X86_64_32:
2230 r_name = "R_X86_64_32";
2231 break;
2232 case elfcpp::R_X86_64_PC32:
2233 r_name = "R_X86_64_PC32";
2234 break;
2235 case elfcpp::R_X86_64_PC32_BND:
2236 r_name = "R_X86_64_PC32_BND";
2237 break;
2238 default:
2239 gold_unreachable();
2240 break;
2241 }
2242 object->error(_("requires dynamic %s reloc against '%s' "
2243 "which may overflow at runtime; recompile "
2244 "with -fPIC"),
2245 r_name, gsym->name());
2246 }
2247 this->issued_non_pic_error_ = true;
2248 return;
2249
2250 default:
2251 // This prevents us from issuing more than one error per reloc
2252 // section. But we can still wind up issuing more than one
2253 // error per object file.
2254 if (this->issued_non_pic_error_)
2255 return;
2256 gold_assert(parameters->options().output_is_position_independent());
2257 object->error(_("requires unsupported dynamic reloc %u; "
2258 "recompile with -fPIC"),
2259 r_type);
2260 this->issued_non_pic_error_ = true;
2261 return;
2262
2263 case elfcpp::R_X86_64_NONE:
2264 gold_unreachable();
2265 }
2266}
2267
2268// Return whether we need to make a PLT entry for a relocation of the
2269// given type against a STT_GNU_IFUNC symbol.
2270
2271template<int size>
2272bool
2273Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc(
2274 Sized_relobj_file<size, false>* object,
2275 unsigned int r_type)
2276{
2277 int flags = Scan::get_reference_flags(r_type);
2278 if (flags & Symbol::TLS_REF)
2279 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
2280 object->name().c_str(), r_type);
2281 return flags != 0;
2282}
2283
2284// Scan a relocation for a local symbol.
2285
2286template<int size>
2287inline void
2288Target_x86_64<size>::Scan::local(Symbol_table* symtab,
2289 Layout* layout,
2290 Target_x86_64<size>* target,
2291 Sized_relobj_file<size, false>* object,
2292 unsigned int data_shndx,
2293 Output_section* output_section,
2294 const elfcpp::Rela<size, false>& reloc,
2295 unsigned int r_type,
2296 const elfcpp::Sym<size, false>& lsym,
2297 bool is_discarded)
2298{
2299 if (is_discarded)
2300 return;
2301
2302 // A local STT_GNU_IFUNC symbol may require a PLT entry.
2303 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
2304 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
2305 {
2306 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2307 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
2308 }
2309
2310 switch (r_type)
2311 {
2312 case elfcpp::R_X86_64_NONE:
2313 case elfcpp::R_X86_64_GNU_VTINHERIT:
2314 case elfcpp::R_X86_64_GNU_VTENTRY:
2315 break;
2316
2317 case elfcpp::R_X86_64_64:
2318 // If building a shared library (or a position-independent
2319 // executable), we need to create a dynamic relocation for this
2320 // location. The relocation applied at link time will apply the
2321 // link-time value, so we flag the location with an
2322 // R_X86_64_RELATIVE relocation so the dynamic loader can
2323 // relocate it easily.
2324 if (parameters->options().output_is_position_independent())
2325 {
2326 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2327 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2328 rela_dyn->add_local_relative(object, r_sym,
2329 (size == 32
2330 ? elfcpp::R_X86_64_RELATIVE64
2331 : elfcpp::R_X86_64_RELATIVE),
2332 output_section, data_shndx,
2333 reloc.get_r_offset(),
2334 reloc.get_r_addend(), is_ifunc);
2335 }
2336 break;
2337
2338 case elfcpp::R_X86_64_32:
2339 case elfcpp::R_X86_64_32S:
2340 case elfcpp::R_X86_64_16:
2341 case elfcpp::R_X86_64_8:
2342 // If building a shared library (or a position-independent
2343 // executable), we need to create a dynamic relocation for this
2344 // location. We can't use an R_X86_64_RELATIVE relocation
2345 // because that is always a 64-bit relocation.
2346 if (parameters->options().output_is_position_independent())
2347 {
2348 // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32.
2349 if (size == 32 && r_type == elfcpp::R_X86_64_32)
2350 {
2351 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2352 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2353 rela_dyn->add_local_relative(object, r_sym,
2354 elfcpp::R_X86_64_RELATIVE,
2355 output_section, data_shndx,
2356 reloc.get_r_offset(),
2357 reloc.get_r_addend(), is_ifunc);
2358 break;
2359 }
2360
2361 this->check_non_pic(object, r_type, NULL);
2362
2363 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2364 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2365 if (lsym.get_st_type() != elfcpp::STT_SECTION)
2366 rela_dyn->add_local(object, r_sym, r_type, output_section,
2367 data_shndx, reloc.get_r_offset(),
2368 reloc.get_r_addend());
2369 else
2370 {
2371 gold_assert(lsym.get_st_value() == 0);
2372 unsigned int shndx = lsym.get_st_shndx();
2373 bool is_ordinary;
2374 shndx = object->adjust_sym_shndx(r_sym, shndx,
2375 &is_ordinary);
2376 if (!is_ordinary)
2377 object->error(_("section symbol %u has bad shndx %u"),
2378 r_sym, shndx);
2379 else
2380 rela_dyn->add_local_section(object, shndx,
2381 r_type, output_section,
2382 data_shndx, reloc.get_r_offset(),
2383 reloc.get_r_addend());
2384 }
2385 }
2386 break;
2387
2388 case elfcpp::R_X86_64_PC64:
2389 case elfcpp::R_X86_64_PC32:
2390 case elfcpp::R_X86_64_PC32_BND:
2391 case elfcpp::R_X86_64_PC16:
2392 case elfcpp::R_X86_64_PC8:
2393 break;
2394
2395 case elfcpp::R_X86_64_PLT32:
2396 case elfcpp::R_X86_64_PLT32_BND:
2397 // Since we know this is a local symbol, we can handle this as a
2398 // PC32 reloc.
2399 break;
2400
2401 case elfcpp::R_X86_64_GOTPC32:
2402 case elfcpp::R_X86_64_GOTOFF64:
2403 case elfcpp::R_X86_64_GOTPC64:
2404 case elfcpp::R_X86_64_PLTOFF64:
2405 // We need a GOT section.
2406 target->got_section(symtab, layout);
2407 // For PLTOFF64, we'd normally want a PLT section, but since we
2408 // know this is a local symbol, no PLT is needed.
2409 break;
2410
2411 case elfcpp::R_X86_64_GOT64:
2412 case elfcpp::R_X86_64_GOT32:
2413 case elfcpp::R_X86_64_GOTPCREL64:
2414 case elfcpp::R_X86_64_GOTPCREL:
2415 case elfcpp::R_X86_64_GOTPLT64:
2416 {
2417 // The symbol requires a GOT entry.
2418 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2419 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2420
2421 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
2422 // lets function pointers compare correctly with shared
2423 // libraries. Otherwise we would need an IRELATIVE reloc.
2424 bool is_new;
2425 if (is_ifunc)
2426 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
2427 else
2428 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
2429 if (is_new)
2430 {
2431 // If we are generating a shared object, we need to add a
2432 // dynamic relocation for this symbol's GOT entry.
2433 if (parameters->options().output_is_position_independent())
2434 {
2435 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2436 // R_X86_64_RELATIVE assumes a 64-bit relocation.
2437 if (r_type != elfcpp::R_X86_64_GOT32)
2438 {
2439 unsigned int got_offset =
2440 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
2441 rela_dyn->add_local_relative(object, r_sym,
2442 elfcpp::R_X86_64_RELATIVE,
2443 got, got_offset, 0, is_ifunc);
2444 }
2445 else
2446 {
2447 this->check_non_pic(object, r_type, NULL);
2448
2449 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2450 rela_dyn->add_local(
2451 object, r_sym, r_type, got,
2452 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
2453 }
2454 }
2455 }
2456 // For GOTPLT64, we'd normally want a PLT section, but since
2457 // we know this is a local symbol, no PLT is needed.
2458 }
2459 break;
2460
2461 case elfcpp::R_X86_64_COPY:
2462 case elfcpp::R_X86_64_GLOB_DAT:
2463 case elfcpp::R_X86_64_JUMP_SLOT:
2464 case elfcpp::R_X86_64_RELATIVE:
2465 case elfcpp::R_X86_64_IRELATIVE:
2466 // These are outstanding tls relocs, which are unexpected when linking
2467 case elfcpp::R_X86_64_TPOFF64:
2468 case elfcpp::R_X86_64_DTPMOD64:
2469 case elfcpp::R_X86_64_TLSDESC:
2470 gold_error(_("%s: unexpected reloc %u in object file"),
2471 object->name().c_str(), r_type);
2472 break;
2473
2474 // These are initial tls relocs, which are expected when linking
2475 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2476 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2477 case elfcpp::R_X86_64_TLSDESC_CALL:
2478 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2479 case elfcpp::R_X86_64_DTPOFF32:
2480 case elfcpp::R_X86_64_DTPOFF64:
2481 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2482 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2483 {
2484 bool output_is_shared = parameters->options().shared();
2485 const tls::Tls_optimization optimized_type
2486 = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared,
2487 r_type);
2488 switch (r_type)
2489 {
2490 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2491 if (optimized_type == tls::TLSOPT_NONE)
2492 {
2493 // Create a pair of GOT entries for the module index and
2494 // dtv-relative offset.
2495 Output_data_got<64, false>* got
2496 = target->got_section(symtab, layout);
2497 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2498 unsigned int shndx = lsym.get_st_shndx();
2499 bool is_ordinary;
2500 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
2501 if (!is_ordinary)
2502 object->error(_("local symbol %u has bad shndx %u"),
2503 r_sym, shndx);
2504 else
2505 got->add_local_pair_with_rel(object, r_sym,
2506 shndx,
2507 GOT_TYPE_TLS_PAIR,
2508 target->rela_dyn_section(layout),
2509 elfcpp::R_X86_64_DTPMOD64);
2510 }
2511 else if (optimized_type != tls::TLSOPT_TO_LE)
2512 unsupported_reloc_local(object, r_type);
2513 break;
2514
2515 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2516 target->define_tls_base_symbol(symtab, layout);
2517 if (optimized_type == tls::TLSOPT_NONE)
2518 {
2519 // Create reserved PLT and GOT entries for the resolver.
2520 target->reserve_tlsdesc_entries(symtab, layout);
2521
2522 // Generate a double GOT entry with an
2523 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
2524 // is resolved lazily, so the GOT entry needs to be in
2525 // an area in .got.plt, not .got. Call got_section to
2526 // make sure the section has been created.
2527 target->got_section(symtab, layout);
2528 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2529 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2530 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
2531 {
2532 unsigned int got_offset = got->add_constant(0);
2533 got->add_constant(0);
2534 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
2535 got_offset);
2536 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2537 // We store the arguments we need in a vector, and
2538 // use the index into the vector as the parameter
2539 // to pass to the target specific routines.
2540 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
2541 void* arg = reinterpret_cast<void*>(intarg);
2542 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
2543 got, got_offset, 0);
2544 }
2545 }
2546 else if (optimized_type != tls::TLSOPT_TO_LE)
2547 unsupported_reloc_local(object, r_type);
2548 break;
2549
2550 case elfcpp::R_X86_64_TLSDESC_CALL:
2551 break;
2552
2553 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2554 if (optimized_type == tls::TLSOPT_NONE)
2555 {
2556 // Create a GOT entry for the module index.
2557 target->got_mod_index_entry(symtab, layout, object);
2558 }
2559 else if (optimized_type != tls::TLSOPT_TO_LE)
2560 unsupported_reloc_local(object, r_type);
2561 break;
2562
2563 case elfcpp::R_X86_64_DTPOFF32:
2564 case elfcpp::R_X86_64_DTPOFF64:
2565 break;
2566
2567 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2568 layout->set_has_static_tls();
2569 if (optimized_type == tls::TLSOPT_NONE)
2570 {
2571 // Create a GOT entry for the tp-relative offset.
2572 Output_data_got<64, false>* got
2573 = target->got_section(symtab, layout);
2574 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2575 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET,
2576 target->rela_dyn_section(layout),
2577 elfcpp::R_X86_64_TPOFF64);
2578 }
2579 else if (optimized_type != tls::TLSOPT_TO_LE)
2580 unsupported_reloc_local(object, r_type);
2581 break;
2582
2583 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2584 layout->set_has_static_tls();
2585 if (output_is_shared)
2586 unsupported_reloc_local(object, r_type);
2587 break;
2588
2589 default:
2590 gold_unreachable();
2591 }
2592 }
2593 break;
2594
2595 case elfcpp::R_X86_64_SIZE32:
2596 case elfcpp::R_X86_64_SIZE64:
2597 default:
2598 gold_error(_("%s: unsupported reloc %u against local symbol"),
2599 object->name().c_str(), r_type);
2600 break;
2601 }
2602}
2603
2604
2605// Report an unsupported relocation against a global symbol.
2606
2607template<int size>
2608void
2609Target_x86_64<size>::Scan::unsupported_reloc_global(
2610 Sized_relobj_file<size, false>* object,
2611 unsigned int r_type,
2612 Symbol* gsym)
2613{
2614 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2615 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2616}
2617
2618// Returns true if this relocation type could be that of a function pointer.
2619template<int size>
2620inline bool
2621Target_x86_64<size>::Scan::possible_function_pointer_reloc(unsigned int r_type)
2622{
2623 switch (r_type)
2624 {
2625 case elfcpp::R_X86_64_64:
2626 case elfcpp::R_X86_64_32:
2627 case elfcpp::R_X86_64_32S:
2628 case elfcpp::R_X86_64_16:
2629 case elfcpp::R_X86_64_8:
2630 case elfcpp::R_X86_64_GOT64:
2631 case elfcpp::R_X86_64_GOT32:
2632 case elfcpp::R_X86_64_GOTPCREL64:
2633 case elfcpp::R_X86_64_GOTPCREL:
2634 case elfcpp::R_X86_64_GOTPLT64:
2635 {
2636 return true;
2637 }
2638 }
2639 return false;
2640}
2641
2642// For safe ICF, scan a relocation for a local symbol to check if it
2643// corresponds to a function pointer being taken. In that case mark
2644// the function whose pointer was taken as not foldable.
2645
2646template<int size>
2647inline bool
2648Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer(
2649 Symbol_table* ,
2650 Layout* ,
2651 Target_x86_64<size>* ,
2652 Sized_relobj_file<size, false>* ,
2653 unsigned int ,
2654 Output_section* ,
2655 const elfcpp::Rela<size, false>& ,
2656 unsigned int r_type,
2657 const elfcpp::Sym<size, false>&)
2658{
2659 // When building a shared library, do not fold any local symbols as it is
2660 // not possible to distinguish pointer taken versus a call by looking at
2661 // the relocation types.
2662 return (parameters->options().shared()
2663 || possible_function_pointer_reloc(r_type));
2664}
2665
2666// For safe ICF, scan a relocation for a global symbol to check if it
2667// corresponds to a function pointer being taken. In that case mark
2668// the function whose pointer was taken as not foldable.
2669
2670template<int size>
2671inline bool
2672Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer(
2673 Symbol_table*,
2674 Layout* ,
2675 Target_x86_64<size>* ,
2676 Sized_relobj_file<size, false>* ,
2677 unsigned int ,
2678 Output_section* ,
2679 const elfcpp::Rela<size, false>& ,
2680 unsigned int r_type,
2681 Symbol* gsym)
2682{
2683 // When building a shared library, do not fold symbols whose visibility
2684 // is hidden, internal or protected.
2685 return ((parameters->options().shared()
2686 && (gsym->visibility() == elfcpp::STV_INTERNAL
2687 || gsym->visibility() == elfcpp::STV_PROTECTED
2688 || gsym->visibility() == elfcpp::STV_HIDDEN))
2689 || possible_function_pointer_reloc(r_type));
2690}
2691
2692// Scan a relocation for a global symbol.
2693
2694template<int size>
2695inline void
2696Target_x86_64<size>::Scan::global(Symbol_table* symtab,
2697 Layout* layout,
2698 Target_x86_64<size>* target,
2699 Sized_relobj_file<size, false>* object,
2700 unsigned int data_shndx,
2701 Output_section* output_section,
2702 const elfcpp::Rela<size, false>& reloc,
2703 unsigned int r_type,
2704 Symbol* gsym)
2705{
2706 // A STT_GNU_IFUNC symbol may require a PLT entry.
2707 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2708 && this->reloc_needs_plt_for_ifunc(object, r_type))
2709 target->make_plt_entry(symtab, layout, gsym);
2710
2711 switch (r_type)
2712 {
2713 case elfcpp::R_X86_64_NONE:
2714 case elfcpp::R_X86_64_GNU_VTINHERIT:
2715 case elfcpp::R_X86_64_GNU_VTENTRY:
2716 break;
2717
2718 case elfcpp::R_X86_64_64:
2719 case elfcpp::R_X86_64_32:
2720 case elfcpp::R_X86_64_32S:
2721 case elfcpp::R_X86_64_16:
2722 case elfcpp::R_X86_64_8:
2723 {
2724 // Make a PLT entry if necessary.
2725 if (gsym->needs_plt_entry())
2726 {
2727 target->make_plt_entry(symtab, layout, gsym);
2728 // Since this is not a PC-relative relocation, we may be
2729 // taking the address of a function. In that case we need to
2730 // set the entry in the dynamic symbol table to the address of
2731 // the PLT entry.
2732 if (gsym->is_from_dynobj() && !parameters->options().shared())
2733 gsym->set_needs_dynsym_value();
2734 }
2735 // Make a dynamic relocation if necessary.
2736 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2737 {
2738 if (gsym->may_need_copy_reloc())
2739 {
2740 target->copy_reloc(symtab, layout, object,
2741 data_shndx, output_section, gsym, reloc);
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->type() == elfcpp::STT_GNU_IFUNC
2746 && gsym->can_use_relative_reloc(false)
2747 && !gsym->is_from_dynobj()
2748 && !gsym->is_undefined()
2749 && !gsym->is_preemptible())
2750 {
2751 // Use an IRELATIVE reloc for a locally defined
2752 // STT_GNU_IFUNC symbol. This makes a function
2753 // address in a PIE executable match the address in a
2754 // shared library that it links against.
2755 Reloc_section* rela_dyn =
2756 target->rela_irelative_section(layout);
2757 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
2758 rela_dyn->add_symbolless_global_addend(gsym, r_type,
2759 output_section, object,
2760 data_shndx,
2761 reloc.get_r_offset(),
2762 reloc.get_r_addend());
2763 }
2764 else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
2765 || (size == 32 && r_type == elfcpp::R_X86_64_32))
2766 && gsym->can_use_relative_reloc(false))
2767 {
2768 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2769 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
2770 output_section, object,
2771 data_shndx,
2772 reloc.get_r_offset(),
2773 reloc.get_r_addend(), false);
2774 }
2775 else
2776 {
2777 this->check_non_pic(object, r_type, gsym);
2778 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2779 rela_dyn->add_global(gsym, r_type, output_section, object,
2780 data_shndx, reloc.get_r_offset(),
2781 reloc.get_r_addend());
2782 }
2783 }
2784 }
2785 break;
2786
2787 case elfcpp::R_X86_64_PC64:
2788 case elfcpp::R_X86_64_PC32:
2789 case elfcpp::R_X86_64_PC32_BND:
2790 case elfcpp::R_X86_64_PC16:
2791 case elfcpp::R_X86_64_PC8:
2792 {
2793 // Make a PLT entry if necessary.
2794 if (gsym->needs_plt_entry())
2795 target->make_plt_entry(symtab, layout, gsym);
2796 // Make a dynamic relocation if necessary.
2797 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2798 {
2799 if (gsym->may_need_copy_reloc())
2800 {
2801 target->copy_reloc(symtab, layout, object,
2802 data_shndx, output_section, gsym, reloc);
2803 }
2804 else
2805 {
2806 this->check_non_pic(object, r_type, gsym);
2807 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2808 rela_dyn->add_global(gsym, r_type, output_section, object,
2809 data_shndx, reloc.get_r_offset(),
2810 reloc.get_r_addend());
2811 }
2812 }
2813 }
2814 break;
2815
2816 case elfcpp::R_X86_64_GOT64:
2817 case elfcpp::R_X86_64_GOT32:
2818 case elfcpp::R_X86_64_GOTPCREL64:
2819 case elfcpp::R_X86_64_GOTPCREL:
2820 case elfcpp::R_X86_64_GOTPLT64:
2821 {
2822 // The symbol requires a GOT entry.
2823 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2824 if (gsym->final_value_is_known())
2825 {
2826 // For a STT_GNU_IFUNC symbol we want the PLT address.
2827 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2828 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2829 else
2830 got->add_global(gsym, GOT_TYPE_STANDARD);
2831 }
2832 else
2833 {
2834 // If this symbol is not fully resolved, we need to add a
2835 // dynamic relocation for it.
2836 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2837
2838 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2839 //
2840 // 1) The symbol may be defined in some other module.
2841 //
2842 // 2) We are building a shared library and this is a
2843 // protected symbol; using GLOB_DAT means that the dynamic
2844 // linker can use the address of the PLT in the main
2845 // executable when appropriate so that function address
2846 // comparisons work.
2847 //
2848 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2849 // code, again so that function address comparisons work.
2850 if (gsym->is_from_dynobj()
2851 || gsym->is_undefined()
2852 || gsym->is_preemptible()
2853 || (gsym->visibility() == elfcpp::STV_PROTECTED
2854 && parameters->options().shared())
2855 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2856 && parameters->options().output_is_position_independent()))
2857 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn,
2858 elfcpp::R_X86_64_GLOB_DAT);
2859 else
2860 {
2861 // For a STT_GNU_IFUNC symbol we want to write the PLT
2862 // offset into the GOT, so that function pointer
2863 // comparisons work correctly.
2864 bool is_new;
2865 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2866 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2867 else
2868 {
2869 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2870 // Tell the dynamic linker to use the PLT address
2871 // when resolving relocations.
2872 if (gsym->is_from_dynobj()
2873 && !parameters->options().shared())
2874 gsym->set_needs_dynsym_value();
2875 }
2876 if (is_new)
2877 {
2878 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2879 rela_dyn->add_global_relative(gsym,
2880 elfcpp::R_X86_64_RELATIVE,
2881 got, got_off, 0, false);
2882 }
2883 }
2884 }
2885 // For GOTPLT64, we also need a PLT entry (but only if the
2886 // symbol is not fully resolved).
2887 if (r_type == elfcpp::R_X86_64_GOTPLT64
2888 && !gsym->final_value_is_known())
2889 target->make_plt_entry(symtab, layout, gsym);
2890 }
2891 break;
2892
2893 case elfcpp::R_X86_64_PLT32:
2894 case elfcpp::R_X86_64_PLT32_BND:
2895 // If the symbol is fully resolved, this is just a PC32 reloc.
2896 // Otherwise we need a PLT entry.
2897 if (gsym->final_value_is_known())
2898 break;
2899 // If building a shared library, we can also skip the PLT entry
2900 // if the symbol is defined in the output file and is protected
2901 // or hidden.
2902 if (gsym->is_defined()
2903 && !gsym->is_from_dynobj()
2904 && !gsym->is_preemptible())
2905 break;
2906 target->make_plt_entry(symtab, layout, gsym);
2907 break;
2908
2909 case elfcpp::R_X86_64_GOTPC32:
2910 case elfcpp::R_X86_64_GOTOFF64:
2911 case elfcpp::R_X86_64_GOTPC64:
2912 case elfcpp::R_X86_64_PLTOFF64:
2913 // We need a GOT section.
2914 target->got_section(symtab, layout);
2915 // For PLTOFF64, we also need a PLT entry (but only if the
2916 // symbol is not fully resolved).
2917 if (r_type == elfcpp::R_X86_64_PLTOFF64
2918 && !gsym->final_value_is_known())
2919 target->make_plt_entry(symtab, layout, gsym);
2920 break;
2921
2922 case elfcpp::R_X86_64_COPY:
2923 case elfcpp::R_X86_64_GLOB_DAT:
2924 case elfcpp::R_X86_64_JUMP_SLOT:
2925 case elfcpp::R_X86_64_RELATIVE:
2926 case elfcpp::R_X86_64_IRELATIVE:
2927 // These are outstanding tls relocs, which are unexpected when linking
2928 case elfcpp::R_X86_64_TPOFF64:
2929 case elfcpp::R_X86_64_DTPMOD64:
2930 case elfcpp::R_X86_64_TLSDESC:
2931 gold_error(_("%s: unexpected reloc %u in object file"),
2932 object->name().c_str(), r_type);
2933 break;
2934
2935 // These are initial tls relocs, which are expected for global()
2936 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2937 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2938 case elfcpp::R_X86_64_TLSDESC_CALL:
2939 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2940 case elfcpp::R_X86_64_DTPOFF32:
2941 case elfcpp::R_X86_64_DTPOFF64:
2942 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2943 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2944 {
2945 const bool is_final = gsym->final_value_is_known();
2946 const tls::Tls_optimization optimized_type
2947 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
2948 switch (r_type)
2949 {
2950 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2951 if (optimized_type == tls::TLSOPT_NONE)
2952 {
2953 // Create a pair of GOT entries for the module index and
2954 // dtv-relative offset.
2955 Output_data_got<64, false>* got
2956 = target->got_section(symtab, layout);
2957 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2958 target->rela_dyn_section(layout),
2959 elfcpp::R_X86_64_DTPMOD64,
2960 elfcpp::R_X86_64_DTPOFF64);
2961 }
2962 else if (optimized_type == tls::TLSOPT_TO_IE)
2963 {
2964 // Create a GOT entry for the tp-relative offset.
2965 Output_data_got<64, false>* got
2966 = target->got_section(symtab, layout);
2967 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2968 target->rela_dyn_section(layout),
2969 elfcpp::R_X86_64_TPOFF64);
2970 }
2971 else if (optimized_type != tls::TLSOPT_TO_LE)
2972 unsupported_reloc_global(object, r_type, gsym);
2973 break;
2974
2975 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2976 target->define_tls_base_symbol(symtab, layout);
2977 if (optimized_type == tls::TLSOPT_NONE)
2978 {
2979 // Create reserved PLT and GOT entries for the resolver.
2980 target->reserve_tlsdesc_entries(symtab, layout);
2981
2982 // Create a double GOT entry with an R_X86_64_TLSDESC
2983 // reloc. The R_X86_64_TLSDESC reloc is resolved
2984 // lazily, so the GOT entry needs to be in an area in
2985 // .got.plt, not .got. Call got_section to make sure
2986 // the section has been created.
2987 target->got_section(symtab, layout);
2988 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2989 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2990 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2991 elfcpp::R_X86_64_TLSDESC, 0);
2992 }
2993 else if (optimized_type == tls::TLSOPT_TO_IE)
2994 {
2995 // Create a GOT entry for the tp-relative offset.
2996 Output_data_got<64, false>* got
2997 = target->got_section(symtab, layout);
2998 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2999 target->rela_dyn_section(layout),
3000 elfcpp::R_X86_64_TPOFF64);
3001 }
3002 else if (optimized_type != tls::TLSOPT_TO_LE)
3003 unsupported_reloc_global(object, r_type, gsym);
3004 break;
3005
3006 case elfcpp::R_X86_64_TLSDESC_CALL:
3007 break;
3008
3009 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3010 if (optimized_type == tls::TLSOPT_NONE)
3011 {
3012 // Create a GOT entry for the module index.
3013 target->got_mod_index_entry(symtab, layout, object);
3014 }
3015 else if (optimized_type != tls::TLSOPT_TO_LE)
3016 unsupported_reloc_global(object, r_type, gsym);
3017 break;
3018
3019 case elfcpp::R_X86_64_DTPOFF32:
3020 case elfcpp::R_X86_64_DTPOFF64:
3021 break;
3022
3023 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3024 layout->set_has_static_tls();
3025 if (optimized_type == tls::TLSOPT_NONE)
3026 {
3027 // Create a GOT entry for the tp-relative offset.
3028 Output_data_got<64, false>* got
3029 = target->got_section(symtab, layout);
3030 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
3031 target->rela_dyn_section(layout),
3032 elfcpp::R_X86_64_TPOFF64);
3033 }
3034 else if (optimized_type != tls::TLSOPT_TO_LE)
3035 unsupported_reloc_global(object, r_type, gsym);
3036 break;
3037
3038 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3039 layout->set_has_static_tls();
3040 if (parameters->options().shared())
3041 unsupported_reloc_global(object, r_type, gsym);
3042 break;
3043
3044 default:
3045 gold_unreachable();
3046 }
3047 }
3048 break;
3049
3050 case elfcpp::R_X86_64_SIZE32:
3051 case elfcpp::R_X86_64_SIZE64:
3052 default:
3053 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
3054 object->name().c_str(), r_type,
3055 gsym->demangled_name().c_str());
3056 break;
3057 }
3058}
3059
3060template<int size>
3061void
3062Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab,
3063 Layout* layout,
3064 Sized_relobj_file<size, false>* object,
3065 unsigned int data_shndx,
3066 unsigned int sh_type,
3067 const unsigned char* prelocs,
3068 size_t reloc_count,
3069 Output_section* output_section,
3070 bool needs_special_offset_handling,
3071 size_t local_symbol_count,
3072 const unsigned char* plocal_symbols)
3073{
3074
3075 if (sh_type == elfcpp::SHT_REL)
3076 {
3077 return;
3078 }
3079
3080 gold::gc_process_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
3081 typename Target_x86_64<size>::Scan,
3082 typename Target_x86_64<size>::Relocatable_size_for_reloc>(
3083 symtab,
3084 layout,
3085 this,
3086 object,
3087 data_shndx,
3088 prelocs,
3089 reloc_count,
3090 output_section,
3091 needs_special_offset_handling,
3092 local_symbol_count,
3093 plocal_symbols);
3094
3095}
3096// Scan relocations for a section.
3097
3098template<int size>
3099void
3100Target_x86_64<size>::scan_relocs(Symbol_table* symtab,
3101 Layout* layout,
3102 Sized_relobj_file<size, false>* object,
3103 unsigned int data_shndx,
3104 unsigned int sh_type,
3105 const unsigned char* prelocs,
3106 size_t reloc_count,
3107 Output_section* output_section,
3108 bool needs_special_offset_handling,
3109 size_t local_symbol_count,
3110 const unsigned char* plocal_symbols)
3111{
3112 if (sh_type == elfcpp::SHT_REL)
3113 {
3114 gold_error(_("%s: unsupported REL reloc section"),
3115 object->name().c_str());
3116 return;
3117 }
3118
3119 gold::scan_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
3120 typename Target_x86_64<size>::Scan>(
3121 symtab,
3122 layout,
3123 this,
3124 object,
3125 data_shndx,
3126 prelocs,
3127 reloc_count,
3128 output_section,
3129 needs_special_offset_handling,
3130 local_symbol_count,
3131 plocal_symbols);
3132}
3133
3134// Finalize the sections.
3135
3136template<int size>
3137void
3138Target_x86_64<size>::do_finalize_sections(
3139 Layout* layout,
3140 const Input_objects*,
3141 Symbol_table* symtab)
3142{
3143 const Reloc_section* rel_plt = (this->plt_ == NULL
3144 ? NULL
3145 : this->plt_->rela_plt());
3146 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
3147 this->rela_dyn_, true, false);
3148
3149 // Fill in some more dynamic tags.
3150 Output_data_dynamic* const odyn = layout->dynamic_data();
3151 if (odyn != NULL)
3152 {
3153 if (this->plt_ != NULL
3154 && this->plt_->output_section() != NULL
3155 && this->plt_->has_tlsdesc_entry())
3156 {
3157 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
3158 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
3159 this->got_->finalize_data_size();
3160 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
3161 this->plt_, plt_offset);
3162 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
3163 this->got_, got_offset);
3164 }
3165 }
3166
3167 // Emit any relocs we saved in an attempt to avoid generating COPY
3168 // relocs.
3169 if (this->copy_relocs_.any_saved_relocs())
3170 this->copy_relocs_.emit(this->rela_dyn_section(layout));
3171
3172 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
3173 // the .got.plt section.
3174 Symbol* sym = this->global_offset_table_;
3175 if (sym != NULL)
3176 {
3177 uint64_t data_size = this->got_plt_->current_data_size();
3178 symtab->get_sized_symbol<size>(sym)->set_symsize(data_size);
3179 }
3180
3181 if (parameters->doing_static_link()
3182 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
3183 {
3184 // If linking statically, make sure that the __rela_iplt symbols
3185 // were defined if necessary, even if we didn't create a PLT.
3186 static const Define_symbol_in_segment syms[] =
3187 {
3188 {
3189 "__rela_iplt_start", // name
3190 elfcpp::PT_LOAD, // segment_type
3191 elfcpp::PF_W, // segment_flags_set
3192 elfcpp::PF(0), // segment_flags_clear
3193 0, // value
3194 0, // size
3195 elfcpp::STT_NOTYPE, // type
3196 elfcpp::STB_GLOBAL, // binding
3197 elfcpp::STV_HIDDEN, // visibility
3198 0, // nonvis
3199 Symbol::SEGMENT_START, // offset_from_base
3200 true // only_if_ref
3201 },
3202 {
3203 "__rela_iplt_end", // name
3204 elfcpp::PT_LOAD, // segment_type
3205 elfcpp::PF_W, // segment_flags_set
3206 elfcpp::PF(0), // segment_flags_clear
3207 0, // value
3208 0, // size
3209 elfcpp::STT_NOTYPE, // type
3210 elfcpp::STB_GLOBAL, // binding
3211 elfcpp::STV_HIDDEN, // visibility
3212 0, // nonvis
3213 Symbol::SEGMENT_START, // offset_from_base
3214 true // only_if_ref
3215 }
3216 };
3217
3218 symtab->define_symbols(layout, 2, syms,
3219 layout->script_options()->saw_sections_clause());
3220 }
3221}
3222
3223// Perform a relocation.
3224
3225template<int size>
3226inline bool
3227Target_x86_64<size>::Relocate::relocate(
3228 const Relocate_info<size, false>* relinfo,
3229 Target_x86_64<size>* target,
3230 Output_section*,
3231 size_t relnum,
3232 const elfcpp::Rela<size, false>& rela,
3233 unsigned int r_type,
3234 const Sized_symbol<size>* gsym,
3235 const Symbol_value<size>* psymval,
3236 unsigned char* view,
3237 typename elfcpp::Elf_types<size>::Elf_Addr address,
3238 section_size_type view_size)
3239{
3240 if (this->skip_call_tls_get_addr_)
3241 {
3242 if ((r_type != elfcpp::R_X86_64_PLT32
3243 && r_type != elfcpp::R_X86_64_PLT32_BND
3244 && r_type != elfcpp::R_X86_64_PC32_BND
3245 && r_type != elfcpp::R_X86_64_PC32)
3246 || gsym == NULL
3247 || strcmp(gsym->name(), "__tls_get_addr") != 0)
3248 {
3249 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3250 _("missing expected TLS relocation"));
3251 }
3252 else
3253 {
3254 this->skip_call_tls_get_addr_ = false;
3255 return false;
3256 }
3257 }
3258
3259 if (view == NULL)
3260 return true;
3261
3262 const Sized_relobj_file<size, false>* object = relinfo->object;
3263
3264 // Pick the value to use for symbols defined in the PLT.
3265 Symbol_value<size> symval;
3266 if (gsym != NULL
3267 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
3268 {
3269 symval.set_output_value(target->plt_address_for_global(gsym));
3270 psymval = &symval;
3271 }
3272 else if (gsym == NULL && psymval->is_ifunc_symbol())
3273 {
3274 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3275 if (object->local_has_plt_offset(r_sym))
3276 {
3277 symval.set_output_value(target->plt_address_for_local(object, r_sym));
3278 psymval = &symval;
3279 }
3280 }
3281
3282 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3283
3284 // Get the GOT offset if needed.
3285 // The GOT pointer points to the end of the GOT section.
3286 // We need to subtract the size of the GOT section to get
3287 // the actual offset to use in the relocation.
3288 bool have_got_offset = false;
3289 unsigned int got_offset = 0;
3290 switch (r_type)
3291 {
3292 case elfcpp::R_X86_64_GOT32:
3293 case elfcpp::R_X86_64_GOT64:
3294 case elfcpp::R_X86_64_GOTPLT64:
3295 case elfcpp::R_X86_64_GOTPCREL:
3296 case elfcpp::R_X86_64_GOTPCREL64:
3297 if (gsym != NULL)
3298 {
3299 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
3300 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
3301 }
3302 else
3303 {
3304 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3305 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
3306 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
3307 - target->got_size());
3308 }
3309 have_got_offset = true;
3310 break;
3311
3312 default:
3313 break;
3314 }
3315
3316 switch (r_type)
3317 {
3318 case elfcpp::R_X86_64_NONE:
3319 case elfcpp::R_X86_64_GNU_VTINHERIT:
3320 case elfcpp::R_X86_64_GNU_VTENTRY:
3321 break;
3322
3323 case elfcpp::R_X86_64_64:
3324 Relocate_functions<size, false>::rela64(view, object, psymval, addend);
3325 break;
3326
3327 case elfcpp::R_X86_64_PC64:
3328 Relocate_functions<size, false>::pcrela64(view, object, psymval, addend,
3329 address);
3330 break;
3331
3332 case elfcpp::R_X86_64_32:
3333 // FIXME: we need to verify that value + addend fits into 32 bits:
3334 // uint64_t x = value + addend;
3335 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
3336 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
3337 Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3338 break;
3339
3340 case elfcpp::R_X86_64_32S:
3341 // FIXME: we need to verify that value + addend fits into 32 bits:
3342 // int64_t x = value + addend; // note this quantity is signed!
3343 // x == static_cast<int64_t>(static_cast<int32_t>(x))
3344 Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3345 break;
3346
3347 case elfcpp::R_X86_64_PC32:
3348 case elfcpp::R_X86_64_PC32_BND:
3349 Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3350 address);
3351 break;
3352
3353 case elfcpp::R_X86_64_16:
3354 Relocate_functions<size, false>::rela16(view, object, psymval, addend);
3355 break;
3356
3357 case elfcpp::R_X86_64_PC16:
3358 Relocate_functions<size, false>::pcrela16(view, object, psymval, addend,
3359 address);
3360 break;
3361
3362 case elfcpp::R_X86_64_8:
3363 Relocate_functions<size, false>::rela8(view, object, psymval, addend);
3364 break;
3365
3366 case elfcpp::R_X86_64_PC8:
3367 Relocate_functions<size, false>::pcrela8(view, object, psymval, addend,
3368 address);
3369 break;
3370
3371 case elfcpp::R_X86_64_PLT32:
3372 case elfcpp::R_X86_64_PLT32_BND:
3373 gold_assert(gsym == NULL
3374 || gsym->has_plt_offset()
3375 || gsym->final_value_is_known()
3376 || (gsym->is_defined()
3377 && !gsym->is_from_dynobj()
3378 && !gsym->is_preemptible()));
3379 // Note: while this code looks the same as for R_X86_64_PC32, it
3380 // behaves differently because psymval was set to point to
3381 // the PLT entry, rather than the symbol, in Scan::global().
3382 Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3383 address);
3384 break;
3385
3386 case elfcpp::R_X86_64_PLTOFF64:
3387 {
3388 gold_assert(gsym);
3389 gold_assert(gsym->has_plt_offset()
3390 || gsym->final_value_is_known());
3391 typename elfcpp::Elf_types<size>::Elf_Addr got_address;
3392 got_address = target->got_section(NULL, NULL)->address();
3393 Relocate_functions<size, false>::rela64(view, object, psymval,
3394 addend - got_address);
3395 }
3396
3397 case elfcpp::R_X86_64_GOT32:
3398 gold_assert(have_got_offset);
3399 Relocate_functions<size, false>::rela32(view, got_offset, addend);
3400 break;
3401
3402 case elfcpp::R_X86_64_GOTPC32:
3403 {
3404 gold_assert(gsym);
3405 typename elfcpp::Elf_types<size>::Elf_Addr value;
3406 value = target->got_plt_section()->address();
3407 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3408 }
3409 break;
3410
3411 case elfcpp::R_X86_64_GOT64:
3412 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
3413 // Since we always add a PLT entry, this is equivalent.
3414 case elfcpp::R_X86_64_GOTPLT64:
3415 gold_assert(have_got_offset);
3416 Relocate_functions<size, false>::rela64(view, got_offset, addend);
3417 break;
3418
3419 case elfcpp::R_X86_64_GOTPC64:
3420 {
3421 gold_assert(gsym);
3422 typename elfcpp::Elf_types<size>::Elf_Addr value;
3423 value = target->got_plt_section()->address();
3424 Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3425 }
3426 break;
3427
3428 case elfcpp::R_X86_64_GOTOFF64:
3429 {
3430 typename elfcpp::Elf_types<size>::Elf_Addr value;
3431 value = (psymval->value(object, 0)
3432 - target->got_plt_section()->address());
3433 Relocate_functions<size, false>::rela64(view, value, addend);
3434 }
3435 break;
3436
3437 case elfcpp::R_X86_64_GOTPCREL:
3438 {
3439 gold_assert(have_got_offset);
3440 typename elfcpp::Elf_types<size>::Elf_Addr value;
3441 value = target->got_plt_section()->address() + got_offset;
3442 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3443 }
3444 break;
3445
3446 case elfcpp::R_X86_64_GOTPCREL64:
3447 {
3448 gold_assert(have_got_offset);
3449 typename elfcpp::Elf_types<size>::Elf_Addr value;
3450 value = target->got_plt_section()->address() + got_offset;
3451 Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3452 }
3453 break;
3454
3455 case elfcpp::R_X86_64_COPY:
3456 case elfcpp::R_X86_64_GLOB_DAT:
3457 case elfcpp::R_X86_64_JUMP_SLOT:
3458 case elfcpp::R_X86_64_RELATIVE:
3459 case elfcpp::R_X86_64_IRELATIVE:
3460 // These are outstanding tls relocs, which are unexpected when linking
3461 case elfcpp::R_X86_64_TPOFF64:
3462 case elfcpp::R_X86_64_DTPMOD64:
3463 case elfcpp::R_X86_64_TLSDESC:
3464 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3465 _("unexpected reloc %u in object file"),
3466 r_type);
3467 break;
3468
3469 // These are initial tls relocs, which are expected when linking
3470 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3471 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3472 case elfcpp::R_X86_64_TLSDESC_CALL:
3473 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3474 case elfcpp::R_X86_64_DTPOFF32:
3475 case elfcpp::R_X86_64_DTPOFF64:
3476 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3477 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3478 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
3479 view, address, view_size);
3480 break;
3481
3482 case elfcpp::R_X86_64_SIZE32:
3483 case elfcpp::R_X86_64_SIZE64:
3484 default:
3485 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3486 _("unsupported reloc %u"),
3487 r_type);
3488 break;
3489 }
3490
3491 return true;
3492}
3493
3494// Perform a TLS relocation.
3495
3496template<int size>
3497inline void
3498Target_x86_64<size>::Relocate::relocate_tls(
3499 const Relocate_info<size, false>* relinfo,
3500 Target_x86_64<size>* target,
3501 size_t relnum,
3502 const elfcpp::Rela<size, false>& rela,
3503 unsigned int r_type,
3504 const Sized_symbol<size>* gsym,
3505 const Symbol_value<size>* psymval,
3506 unsigned char* view,
3507 typename elfcpp::Elf_types<size>::Elf_Addr address,
3508 section_size_type view_size)
3509{
3510 Output_segment* tls_segment = relinfo->layout->tls_segment();
3511
3512 const Sized_relobj_file<size, false>* object = relinfo->object;
3513 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3514 elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr);
3515 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
3516
3517 typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0);
3518
3519 const bool is_final = (gsym == NULL
3520 ? !parameters->options().shared()
3521 : gsym->final_value_is_known());
3522 tls::Tls_optimization optimized_type
3523 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
3524 switch (r_type)
3525 {
3526 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3527 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3528 {
3529 // If this code sequence is used in a non-executable section,
3530 // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
3531 // on the assumption that it's being used by itself in a debug
3532 // section. Therefore, in the unlikely event that the code
3533 // sequence appears in a non-executable section, we simply
3534 // leave it unoptimized.
3535 optimized_type = tls::TLSOPT_NONE;
3536 }
3537 if (optimized_type == tls::TLSOPT_TO_LE)
3538 {
3539 if (tls_segment == NULL)
3540 {
3541 gold_assert(parameters->errors()->error_count() > 0
3542 || issue_undefined_symbol_error(gsym));
3543 return;
3544 }
3545 this->tls_gd_to_le(relinfo, relnum, tls_segment,
3546 rela, r_type, value, view,
3547 view_size);
3548 break;
3549 }
3550 else
3551 {
3552 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3553 ? GOT_TYPE_TLS_OFFSET
3554 : GOT_TYPE_TLS_PAIR);
3555 unsigned int got_offset;
3556 if (gsym != NULL)
3557 {
3558 gold_assert(gsym->has_got_offset(got_type));
3559 got_offset = gsym->got_offset(got_type) - target->got_size();
3560 }
3561 else
3562 {
3563 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3564 gold_assert(object->local_has_got_offset(r_sym, got_type));
3565 got_offset = (object->local_got_offset(r_sym, got_type)
3566 - target->got_size());
3567 }
3568 if (optimized_type == tls::TLSOPT_TO_IE)
3569 {
3570 value = target->got_plt_section()->address() + got_offset;
3571 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
3572 value, view, address, view_size);
3573 break;
3574 }
3575 else if (optimized_type == tls::TLSOPT_NONE)
3576 {
3577 // Relocate the field with the offset of the pair of GOT
3578 // entries.
3579 value = target->got_plt_section()->address() + got_offset;
3580 Relocate_functions<size, false>::pcrela32(view, value, addend,
3581 address);
3582 break;
3583 }
3584 }
3585 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3586 _("unsupported reloc %u"), r_type);
3587 break;
3588
3589 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3590 case elfcpp::R_X86_64_TLSDESC_CALL:
3591 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3592 {
3593 // See above comment for R_X86_64_TLSGD.
3594 optimized_type = tls::TLSOPT_NONE;
3595 }
3596 if (optimized_type == tls::TLSOPT_TO_LE)
3597 {
3598 if (tls_segment == NULL)
3599 {
3600 gold_assert(parameters->errors()->error_count() > 0
3601 || issue_undefined_symbol_error(gsym));
3602 return;
3603 }
3604 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3605 rela, r_type, value, view,
3606 view_size);
3607 break;
3608 }
3609 else
3610 {
3611 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3612 ? GOT_TYPE_TLS_OFFSET
3613 : GOT_TYPE_TLS_DESC);
3614 unsigned int got_offset = 0;
3615 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
3616 && optimized_type == tls::TLSOPT_NONE)
3617 {
3618 // We created GOT entries in the .got.tlsdesc portion of
3619 // the .got.plt section, but the offset stored in the
3620 // symbol is the offset within .got.tlsdesc.
3621 got_offset = (target->got_size()
3622 + target->got_plt_section()->data_size());
3623 }
3624 if (gsym != NULL)
3625 {
3626 gold_assert(gsym->has_got_offset(got_type));
3627 got_offset += gsym->got_offset(got_type) - target->got_size();
3628 }
3629 else
3630 {
3631 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3632 gold_assert(object->local_has_got_offset(r_sym, got_type));
3633 got_offset += (object->local_got_offset(r_sym, got_type)
3634 - target->got_size());
3635 }
3636 if (optimized_type == tls::TLSOPT_TO_IE)
3637 {
3638 if (tls_segment == NULL)
3639 {
3640 gold_assert(parameters->errors()->error_count() > 0
3641 || issue_undefined_symbol_error(gsym));
3642 return;
3643 }
3644 value = target->got_plt_section()->address() + got_offset;
3645 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
3646 rela, r_type, value, view, address,
3647 view_size);
3648 break;
3649 }
3650 else if (optimized_type == tls::TLSOPT_NONE)
3651 {
3652 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3653 {
3654 // Relocate the field with the offset of the pair of GOT
3655 // entries.
3656 value = target->got_plt_section()->address() + got_offset;
3657 Relocate_functions<size, false>::pcrela32(view, value, addend,
3658 address);
3659 }
3660 break;
3661 }
3662 }
3663 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3664 _("unsupported reloc %u"), r_type);
3665 break;
3666
3667 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3668 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3669 {
3670 // See above comment for R_X86_64_TLSGD.
3671 optimized_type = tls::TLSOPT_NONE;
3672 }
3673 if (optimized_type == tls::TLSOPT_TO_LE)
3674 {
3675 if (tls_segment == NULL)
3676 {
3677 gold_assert(parameters->errors()->error_count() > 0
3678 || issue_undefined_symbol_error(gsym));
3679 return;
3680 }
3681 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
3682 value, view, view_size);
3683 break;
3684 }
3685 else if (optimized_type == tls::TLSOPT_NONE)
3686 {
3687 // Relocate the field with the offset of the GOT entry for
3688 // the module index.
3689 unsigned int got_offset;
3690 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3691 - target->got_size());
3692 value = target->got_plt_section()->address() + got_offset;
3693 Relocate_functions<size, false>::pcrela32(view, value, addend,
3694 address);
3695 break;
3696 }
3697 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3698 _("unsupported reloc %u"), r_type);
3699 break;
3700
3701 case elfcpp::R_X86_64_DTPOFF32:
3702 // This relocation type is used in debugging information.
3703 // In that case we need to not optimize the value. If the