PR gold/13359
[deliverable/binutils-gdb.git] / gold / x86_64.cc
1 // x86_64.cc -- x86_64 target support for gold.
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26
27 #include "elfcpp.h"
28 #include "dwarf.h"
29 #include "parameters.h"
30 #include "reloc.h"
31 #include "x86_64.h"
32 #include "object.h"
33 #include "symtab.h"
34 #include "layout.h"
35 #include "output.h"
36 #include "copy-relocs.h"
37 #include "target.h"
38 #include "target-reloc.h"
39 #include "target-select.h"
40 #include "tls.h"
41 #include "freebsd.h"
42 #include "gc.h"
43 #include "icf.h"
44
45 namespace
46 {
47
48 using namespace gold;
49
50 // A class to handle the PLT data.
51
52 class Output_data_plt_x86_64 : public Output_section_data
53 {
54 public:
55 typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
56
57 Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
58 Output_data_space* got_plt,
59 Output_data_space* got_irelative)
60 : Output_section_data(16), layout_(layout), tlsdesc_rel_(NULL),
61 irelative_rel_(NULL), got_(got), got_plt_(got_plt),
62 got_irelative_(got_irelative), count_(0), irelative_count_(0),
63 tlsdesc_got_offset_(-1U), free_list_()
64 { this->init(layout); }
65
66 Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
67 Output_data_space* got_plt,
68 Output_data_space* got_irelative,
69 unsigned int plt_count)
70 : Output_section_data((plt_count + 1) * plt_entry_size, 16, false),
71 layout_(layout), tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
72 got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
73 irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
74 {
75 this->init(layout);
76
77 // Initialize the free list and reserve the first entry.
78 this->free_list_.init((plt_count + 1) * plt_entry_size, false);
79 this->free_list_.remove(0, plt_entry_size);
80 }
81
82 // Initialize the PLT section.
83 void
84 init(Layout* layout);
85
86 // Add an entry to the PLT.
87 void
88 add_entry(Symbol_table*, Layout*, Symbol* gsym);
89
90 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
91 unsigned int
92 add_local_ifunc_entry(Symbol_table* symtab, Layout*,
93 Sized_relobj_file<64, false>* relobj,
94 unsigned int local_sym_index);
95
96 // Add the relocation for a PLT entry.
97 void
98 add_relocation(Symbol_table*, Layout*, Symbol* gsym,
99 unsigned int got_offset);
100
101 // Add the reserved TLSDESC_PLT entry to the PLT.
102 void
103 reserve_tlsdesc_entry(unsigned int got_offset)
104 { this->tlsdesc_got_offset_ = got_offset; }
105
106 // Return true if a TLSDESC_PLT entry has been reserved.
107 bool
108 has_tlsdesc_entry() const
109 { return this->tlsdesc_got_offset_ != -1U; }
110
111 // Return the GOT offset for the reserved TLSDESC_PLT entry.
112 unsigned int
113 get_tlsdesc_got_offset() const
114 { return this->tlsdesc_got_offset_; }
115
116 // Return the offset of the reserved TLSDESC_PLT entry.
117 unsigned int
118 get_tlsdesc_plt_offset() const
119 { return (this->count_ + this->irelative_count_ + 1) * plt_entry_size; }
120
121 // Return the .rela.plt section data.
122 Reloc_section*
123 rela_plt()
124 { return this->rel_; }
125
126 // Return where the TLSDESC relocations should go.
127 Reloc_section*
128 rela_tlsdesc(Layout*);
129
130 // Return where the IRELATIVE relocations should go in the PLT
131 // relocations.
132 Reloc_section*
133 rela_irelative(Symbol_table*, Layout*);
134
135 // Return whether we created a section for IRELATIVE relocations.
136 bool
137 has_irelative_section() const
138 { return this->irelative_rel_ != NULL; }
139
140 // Return the number of PLT entries.
141 unsigned int
142 entry_count() const
143 { return this->count_ + this->irelative_count_; }
144
145 // Return the offset of the first non-reserved PLT entry.
146 static unsigned int
147 first_plt_entry_offset()
148 { return plt_entry_size; }
149
150 // Return the size of a PLT entry.
151 static unsigned int
152 get_plt_entry_size()
153 { return plt_entry_size; }
154
155 // Reserve a slot in the PLT for an existing symbol in an incremental update.
156 void
157 reserve_slot(unsigned int plt_index)
158 {
159 this->free_list_.remove((plt_index + 1) * plt_entry_size,
160 (plt_index + 2) * plt_entry_size);
161 }
162
163 // Return the PLT address to use for a global symbol.
164 uint64_t
165 address_for_global(const Symbol*);
166
167 // Return the PLT address to use for a local symbol.
168 uint64_t
169 address_for_local(const Relobj*, unsigned int symndx);
170
171 protected:
172 void
173 do_adjust_output_section(Output_section* os);
174
175 // Write to a map file.
176 void
177 do_print_to_mapfile(Mapfile* mapfile) const
178 { mapfile->print_output_data(this, _("** PLT")); }
179
180 private:
181 // The size of an entry in the PLT.
182 static const int plt_entry_size = 16;
183
184 // The first entry in the PLT.
185 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
186 // procedure linkage table for both programs and shared objects."
187 static const unsigned char first_plt_entry[plt_entry_size];
188
189 // Other entries in the PLT for an executable.
190 static const unsigned char plt_entry[plt_entry_size];
191
192 // The reserved TLSDESC entry in the PLT for an executable.
193 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
194
195 // The .eh_frame unwind information for the PLT.
196 static const int plt_eh_frame_cie_size = 16;
197 static const int plt_eh_frame_fde_size = 32;
198 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
199 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
200
201 // Set the final size.
202 void
203 set_final_data_size();
204
205 // Write out the PLT data.
206 void
207 do_write(Output_file*);
208
209 // A pointer to the Layout class, so that we can find the .dynamic
210 // section when we write out the GOT PLT section.
211 Layout* layout_;
212 // The reloc section.
213 Reloc_section* rel_;
214 // The TLSDESC relocs, if necessary. These must follow the regular
215 // PLT relocs.
216 Reloc_section* tlsdesc_rel_;
217 // The IRELATIVE relocs, if necessary. These must follow the
218 // regular PLT relocations and the TLSDESC relocations.
219 Reloc_section* irelative_rel_;
220 // The .got section.
221 Output_data_got<64, false>* got_;
222 // The .got.plt section.
223 Output_data_space* got_plt_;
224 // The part of the .got.plt section used for IRELATIVE relocs.
225 Output_data_space* got_irelative_;
226 // The number of PLT entries.
227 unsigned int count_;
228 // Number of PLT entries with R_X86_64_IRELATIVE relocs. These
229 // follow the regular PLT entries.
230 unsigned int irelative_count_;
231 // Offset of the reserved TLSDESC_GOT entry when needed.
232 unsigned int tlsdesc_got_offset_;
233 // List of available regions within the section, for incremental
234 // update links.
235 Free_list free_list_;
236 };
237
238 // The x86_64 target class.
239 // See the ABI at
240 // http://www.x86-64.org/documentation/abi.pdf
241 // TLS info comes from
242 // http://people.redhat.com/drepper/tls.pdf
243 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
244
245 class Target_x86_64 : public Sized_target<64, false>
246 {
247 public:
248 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
249 // uses only Elf64_Rela relocation entries with explicit addends."
250 typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
251
252 Target_x86_64()
253 : Sized_target<64, false>(&x86_64_info),
254 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
255 got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL),
256 rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY),
257 dynbss_(NULL), got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
258 tls_base_symbol_defined_(false)
259 { }
260
261 // Hook for a new output section.
262 void
263 do_new_output_section(Output_section*) const;
264
265 // Scan the relocations to look for symbol adjustments.
266 void
267 gc_process_relocs(Symbol_table* symtab,
268 Layout* layout,
269 Sized_relobj_file<64, false>* object,
270 unsigned int data_shndx,
271 unsigned int sh_type,
272 const unsigned char* prelocs,
273 size_t reloc_count,
274 Output_section* output_section,
275 bool needs_special_offset_handling,
276 size_t local_symbol_count,
277 const unsigned char* plocal_symbols);
278
279 // Scan the relocations to look for symbol adjustments.
280 void
281 scan_relocs(Symbol_table* symtab,
282 Layout* layout,
283 Sized_relobj_file<64, false>* object,
284 unsigned int data_shndx,
285 unsigned int sh_type,
286 const unsigned char* prelocs,
287 size_t reloc_count,
288 Output_section* output_section,
289 bool needs_special_offset_handling,
290 size_t local_symbol_count,
291 const unsigned char* plocal_symbols);
292
293 // Finalize the sections.
294 void
295 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
296
297 // Return the value to use for a dynamic which requires special
298 // treatment.
299 uint64_t
300 do_dynsym_value(const Symbol*) const;
301
302 // Relocate a section.
303 void
304 relocate_section(const Relocate_info<64, false>*,
305 unsigned int sh_type,
306 const unsigned char* prelocs,
307 size_t reloc_count,
308 Output_section* output_section,
309 bool needs_special_offset_handling,
310 unsigned char* view,
311 elfcpp::Elf_types<64>::Elf_Addr view_address,
312 section_size_type view_size,
313 const Reloc_symbol_changes*);
314
315 // Scan the relocs during a relocatable link.
316 void
317 scan_relocatable_relocs(Symbol_table* symtab,
318 Layout* layout,
319 Sized_relobj_file<64, false>* object,
320 unsigned int data_shndx,
321 unsigned int sh_type,
322 const unsigned char* prelocs,
323 size_t reloc_count,
324 Output_section* output_section,
325 bool needs_special_offset_handling,
326 size_t local_symbol_count,
327 const unsigned char* plocal_symbols,
328 Relocatable_relocs*);
329
330 // Relocate a section during a relocatable link.
331 void
332 relocate_for_relocatable(const Relocate_info<64, false>*,
333 unsigned int sh_type,
334 const unsigned char* prelocs,
335 size_t reloc_count,
336 Output_section* output_section,
337 off_t offset_in_output_section,
338 const Relocatable_relocs*,
339 unsigned char* view,
340 elfcpp::Elf_types<64>::Elf_Addr view_address,
341 section_size_type view_size,
342 unsigned char* reloc_view,
343 section_size_type reloc_view_size);
344
345 // Return a string used to fill a code section with nops.
346 std::string
347 do_code_fill(section_size_type length) const;
348
349 // Return whether SYM is defined by the ABI.
350 bool
351 do_is_defined_by_abi(const Symbol* sym) const
352 { return strcmp(sym->name(), "__tls_get_addr") == 0; }
353
354 // Return the symbol index to use for a target specific relocation.
355 // The only target specific relocation is R_X86_64_TLSDESC for a
356 // local symbol, which is an absolute reloc.
357 unsigned int
358 do_reloc_symbol_index(void*, unsigned int r_type) const
359 {
360 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
361 return 0;
362 }
363
364 // Return the addend to use for a target specific relocation.
365 uint64_t
366 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
367
368 // Return the PLT section.
369 uint64_t
370 do_plt_address_for_global(const Symbol* gsym) const
371 { return this->plt_section()->address_for_global(gsym); }
372
373 uint64_t
374 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
375 { return this->plt_section()->address_for_local(relobj, symndx); }
376
377 // This function should be defined in targets that can use relocation
378 // types to determine (implemented in local_reloc_may_be_function_pointer
379 // and global_reloc_may_be_function_pointer)
380 // if a function's pointer is taken. ICF uses this in safe mode to only
381 // fold those functions whose pointer is defintely not taken. For x86_64
382 // pie binaries, safe ICF cannot be done by looking at relocation types.
383 bool
384 do_can_check_for_function_pointers() const
385 { return !parameters->options().pie(); }
386
387 // Return the base for a DW_EH_PE_datarel encoding.
388 uint64_t
389 do_ehframe_datarel_base() const;
390
391 // Adjust -fsplit-stack code which calls non-split-stack code.
392 void
393 do_calls_non_split(Relobj* object, unsigned int shndx,
394 section_offset_type fnoffset, section_size_type fnsize,
395 unsigned char* view, section_size_type view_size,
396 std::string* from, std::string* to) const;
397
398 // Return the size of the GOT section.
399 section_size_type
400 got_size() const
401 {
402 gold_assert(this->got_ != NULL);
403 return this->got_->data_size();
404 }
405
406 // Return the number of entries in the GOT.
407 unsigned int
408 got_entry_count() const
409 {
410 if (this->got_ == NULL)
411 return 0;
412 return this->got_size() / 8;
413 }
414
415 // Return the number of entries in the PLT.
416 unsigned int
417 plt_entry_count() const;
418
419 // Return the offset of the first non-reserved PLT entry.
420 unsigned int
421 first_plt_entry_offset() const;
422
423 // Return the size of each PLT entry.
424 unsigned int
425 plt_entry_size() const;
426
427 // Create the GOT section for an incremental update.
428 Output_data_got<64, false>*
429 init_got_plt_for_update(Symbol_table* symtab,
430 Layout* layout,
431 unsigned int got_count,
432 unsigned int plt_count);
433
434 // Reserve a GOT entry for a local symbol, and regenerate any
435 // necessary dynamic relocations.
436 void
437 reserve_local_got_entry(unsigned int got_index,
438 Sized_relobj<64, false>* obj,
439 unsigned int r_sym,
440 unsigned int got_type);
441
442 // Reserve a GOT entry for a global symbol, and regenerate any
443 // necessary dynamic relocations.
444 void
445 reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
446 unsigned int got_type);
447
448 // Register an existing PLT entry for a global symbol.
449 void
450 register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index,
451 Symbol* gsym);
452
453 // Force a COPY relocation for a given symbol.
454 void
455 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t);
456
457 // Apply an incremental relocation.
458 void
459 apply_relocation(const Relocate_info<64, false>* relinfo,
460 elfcpp::Elf_types<64>::Elf_Addr r_offset,
461 unsigned int r_type,
462 elfcpp::Elf_types<64>::Elf_Swxword r_addend,
463 const Symbol* gsym,
464 unsigned char* view,
465 elfcpp::Elf_types<64>::Elf_Addr address,
466 section_size_type view_size);
467
468 // Add a new reloc argument, returning the index in the vector.
469 size_t
470 add_tlsdesc_info(Sized_relobj_file<64, false>* object, unsigned int r_sym)
471 {
472 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
473 return this->tlsdesc_reloc_info_.size() - 1;
474 }
475
476 private:
477 // The class which scans relocations.
478 class Scan
479 {
480 public:
481 Scan()
482 : issued_non_pic_error_(false)
483 { }
484
485 static inline int
486 get_reference_flags(unsigned int r_type);
487
488 inline void
489 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
490 Sized_relobj_file<64, false>* object,
491 unsigned int data_shndx,
492 Output_section* output_section,
493 const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
494 const elfcpp::Sym<64, false>& lsym);
495
496 inline void
497 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
498 Sized_relobj_file<64, false>* object,
499 unsigned int data_shndx,
500 Output_section* output_section,
501 const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
502 Symbol* gsym);
503
504 inline bool
505 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
506 Target_x86_64* target,
507 Sized_relobj_file<64, false>* object,
508 unsigned int data_shndx,
509 Output_section* output_section,
510 const elfcpp::Rela<64, false>& reloc,
511 unsigned int r_type,
512 const elfcpp::Sym<64, false>& lsym);
513
514 inline bool
515 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
516 Target_x86_64* target,
517 Sized_relobj_file<64, false>* object,
518 unsigned int data_shndx,
519 Output_section* output_section,
520 const elfcpp::Rela<64, false>& reloc,
521 unsigned int r_type,
522 Symbol* gsym);
523
524 private:
525 static void
526 unsupported_reloc_local(Sized_relobj_file<64, false>*, unsigned int r_type);
527
528 static void
529 unsupported_reloc_global(Sized_relobj_file<64, false>*, unsigned int r_type,
530 Symbol*);
531
532 void
533 check_non_pic(Relobj*, unsigned int r_type, Symbol*);
534
535 inline bool
536 possible_function_pointer_reloc(unsigned int r_type);
537
538 bool
539 reloc_needs_plt_for_ifunc(Sized_relobj_file<64, false>*,
540 unsigned int r_type);
541
542 // Whether we have issued an error about a non-PIC compilation.
543 bool issued_non_pic_error_;
544 };
545
546 // The class which implements relocation.
547 class Relocate
548 {
549 public:
550 Relocate()
551 : skip_call_tls_get_addr_(false)
552 { }
553
554 ~Relocate()
555 {
556 if (this->skip_call_tls_get_addr_)
557 {
558 // FIXME: This needs to specify the location somehow.
559 gold_error(_("missing expected TLS relocation"));
560 }
561 }
562
563 // Do a relocation. Return false if the caller should not issue
564 // any warnings about this relocation.
565 inline bool
566 relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
567 size_t relnum, const elfcpp::Rela<64, false>&,
568 unsigned int r_type, const Sized_symbol<64>*,
569 const Symbol_value<64>*,
570 unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
571 section_size_type);
572
573 private:
574 // Do a TLS relocation.
575 inline void
576 relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
577 size_t relnum, const elfcpp::Rela<64, false>&,
578 unsigned int r_type, const Sized_symbol<64>*,
579 const Symbol_value<64>*,
580 unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
581 section_size_type);
582
583 // Do a TLS General-Dynamic to Initial-Exec transition.
584 inline void
585 tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
586 Output_segment* tls_segment,
587 const elfcpp::Rela<64, false>&, unsigned int r_type,
588 elfcpp::Elf_types<64>::Elf_Addr value,
589 unsigned char* view,
590 elfcpp::Elf_types<64>::Elf_Addr,
591 section_size_type view_size);
592
593 // Do a TLS General-Dynamic to Local-Exec transition.
594 inline void
595 tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
596 Output_segment* tls_segment,
597 const elfcpp::Rela<64, false>&, unsigned int r_type,
598 elfcpp::Elf_types<64>::Elf_Addr value,
599 unsigned char* view,
600 section_size_type view_size);
601
602 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
603 inline void
604 tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
605 Output_segment* tls_segment,
606 const elfcpp::Rela<64, false>&, unsigned int r_type,
607 elfcpp::Elf_types<64>::Elf_Addr value,
608 unsigned char* view,
609 elfcpp::Elf_types<64>::Elf_Addr,
610 section_size_type view_size);
611
612 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
613 inline void
614 tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
615 Output_segment* tls_segment,
616 const elfcpp::Rela<64, false>&, unsigned int r_type,
617 elfcpp::Elf_types<64>::Elf_Addr value,
618 unsigned char* view,
619 section_size_type view_size);
620
621 // Do a TLS Local-Dynamic to Local-Exec transition.
622 inline void
623 tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
624 Output_segment* tls_segment,
625 const elfcpp::Rela<64, false>&, unsigned int r_type,
626 elfcpp::Elf_types<64>::Elf_Addr value,
627 unsigned char* view,
628 section_size_type view_size);
629
630 // Do a TLS Initial-Exec to Local-Exec transition.
631 static inline void
632 tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
633 Output_segment* tls_segment,
634 const elfcpp::Rela<64, false>&, unsigned int r_type,
635 elfcpp::Elf_types<64>::Elf_Addr value,
636 unsigned char* view,
637 section_size_type view_size);
638
639 // This is set if we should skip the next reloc, which should be a
640 // PLT32 reloc against ___tls_get_addr.
641 bool skip_call_tls_get_addr_;
642 };
643
644 // A class which returns the size required for a relocation type,
645 // used while scanning relocs during a relocatable link.
646 class Relocatable_size_for_reloc
647 {
648 public:
649 unsigned int
650 get_size_for_reloc(unsigned int, Relobj*);
651 };
652
653 // Adjust TLS relocation type based on the options and whether this
654 // is a local symbol.
655 static tls::Tls_optimization
656 optimize_tls_reloc(bool is_final, int r_type);
657
658 // Get the GOT section, creating it if necessary.
659 Output_data_got<64, false>*
660 got_section(Symbol_table*, Layout*);
661
662 // Get the GOT PLT section.
663 Output_data_space*
664 got_plt_section() const
665 {
666 gold_assert(this->got_plt_ != NULL);
667 return this->got_plt_;
668 }
669
670 // Get the GOT section for TLSDESC entries.
671 Output_data_got<64, false>*
672 got_tlsdesc_section() const
673 {
674 gold_assert(this->got_tlsdesc_ != NULL);
675 return this->got_tlsdesc_;
676 }
677
678 // Create the PLT section.
679 void
680 make_plt_section(Symbol_table* symtab, Layout* layout);
681
682 // Create a PLT entry for a global symbol.
683 void
684 make_plt_entry(Symbol_table*, Layout*, Symbol*);
685
686 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
687 void
688 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
689 Sized_relobj_file<64, false>* relobj,
690 unsigned int local_sym_index);
691
692 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
693 void
694 define_tls_base_symbol(Symbol_table*, Layout*);
695
696 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
697 void
698 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
699
700 // Create a GOT entry for the TLS module index.
701 unsigned int
702 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
703 Sized_relobj_file<64, false>* object);
704
705 // Get the PLT section.
706 Output_data_plt_x86_64*
707 plt_section() const
708 {
709 gold_assert(this->plt_ != NULL);
710 return this->plt_;
711 }
712
713 // Get the dynamic reloc section, creating it if necessary.
714 Reloc_section*
715 rela_dyn_section(Layout*);
716
717 // Get the section to use for TLSDESC relocations.
718 Reloc_section*
719 rela_tlsdesc_section(Layout*) const;
720
721 // Get the section to use for IRELATIVE relocations.
722 Reloc_section*
723 rela_irelative_section(Layout*);
724
725 // Add a potential copy relocation.
726 void
727 copy_reloc(Symbol_table* symtab, Layout* layout,
728 Sized_relobj_file<64, false>* object,
729 unsigned int shndx, Output_section* output_section,
730 Symbol* sym, const elfcpp::Rela<64, false>& reloc)
731 {
732 this->copy_relocs_.copy_reloc(symtab, layout,
733 symtab->get_sized_symbol<64>(sym),
734 object, shndx, output_section,
735 reloc, this->rela_dyn_section(layout));
736 }
737
738 // Information about this specific target which we pass to the
739 // general Target structure.
740 static const Target::Target_info x86_64_info;
741
742 // The types of GOT entries needed for this platform.
743 // These values are exposed to the ABI in an incremental link.
744 // Do not renumber existing values without changing the version
745 // number of the .gnu_incremental_inputs section.
746 enum Got_type
747 {
748 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
749 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset
750 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
751 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
752 };
753
754 // This type is used as the argument to the target specific
755 // relocation routines. The only target specific reloc is
756 // R_X86_64_TLSDESC against a local symbol.
757 struct Tlsdesc_info
758 {
759 Tlsdesc_info(Sized_relobj_file<64, false>* a_object, unsigned int a_r_sym)
760 : object(a_object), r_sym(a_r_sym)
761 { }
762
763 // The object in which the local symbol is defined.
764 Sized_relobj_file<64, false>* object;
765 // The local symbol index in the object.
766 unsigned int r_sym;
767 };
768
769 // The GOT section.
770 Output_data_got<64, false>* got_;
771 // The PLT section.
772 Output_data_plt_x86_64* plt_;
773 // The GOT PLT section.
774 Output_data_space* got_plt_;
775 // The GOT section for IRELATIVE relocations.
776 Output_data_space* got_irelative_;
777 // The GOT section for TLSDESC relocations.
778 Output_data_got<64, false>* got_tlsdesc_;
779 // The _GLOBAL_OFFSET_TABLE_ symbol.
780 Symbol* global_offset_table_;
781 // The dynamic reloc section.
782 Reloc_section* rela_dyn_;
783 // The section to use for IRELATIVE relocs.
784 Reloc_section* rela_irelative_;
785 // Relocs saved to avoid a COPY reloc.
786 Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
787 // Space for variables copied with a COPY reloc.
788 Output_data_space* dynbss_;
789 // Offset of the GOT entry for the TLS module index.
790 unsigned int got_mod_index_offset_;
791 // We handle R_X86_64_TLSDESC against a local symbol as a target
792 // specific relocation. Here we store the object and local symbol
793 // index for the relocation.
794 std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
795 // True if the _TLS_MODULE_BASE_ symbol has been defined.
796 bool tls_base_symbol_defined_;
797 };
798
799 const Target::Target_info Target_x86_64::x86_64_info =
800 {
801 64, // size
802 false, // is_big_endian
803 elfcpp::EM_X86_64, // machine_code
804 false, // has_make_symbol
805 false, // has_resolve
806 true, // has_code_fill
807 true, // is_default_stack_executable
808 true, // can_icf_inline_merge_sections
809 '\0', // wrap_char
810 "/lib/ld64.so.1", // program interpreter
811 0x400000, // default_text_segment_address
812 0x1000, // abi_pagesize (overridable by -z max-page-size)
813 0x1000, // common_pagesize (overridable by -z common-page-size)
814 elfcpp::SHN_UNDEF, // small_common_shndx
815 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
816 0, // small_common_section_flags
817 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
818 NULL, // attributes_section
819 NULL // attributes_vendor
820 };
821
822 // This is called when a new output section is created. This is where
823 // we handle the SHF_X86_64_LARGE.
824
825 void
826 Target_x86_64::do_new_output_section(Output_section* os) const
827 {
828 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
829 os->set_is_large_section();
830 }
831
832 // Get the GOT section, creating it if necessary.
833
834 Output_data_got<64, false>*
835 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
836 {
837 if (this->got_ == NULL)
838 {
839 gold_assert(symtab != NULL && layout != NULL);
840
841 // When using -z now, we can treat .got.plt as a relro section.
842 // Without -z now, it is modified after program startup by lazy
843 // PLT relocations.
844 bool is_got_plt_relro = parameters->options().now();
845 Output_section_order got_order = (is_got_plt_relro
846 ? ORDER_RELRO
847 : ORDER_RELRO_LAST);
848 Output_section_order got_plt_order = (is_got_plt_relro
849 ? ORDER_RELRO
850 : ORDER_NON_RELRO_FIRST);
851
852 this->got_ = new Output_data_got<64, false>();
853
854 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
855 (elfcpp::SHF_ALLOC
856 | elfcpp::SHF_WRITE),
857 this->got_, got_order, true);
858
859 this->got_plt_ = new Output_data_space(8, "** GOT PLT");
860 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
861 (elfcpp::SHF_ALLOC
862 | elfcpp::SHF_WRITE),
863 this->got_plt_, got_plt_order,
864 is_got_plt_relro);
865
866 // The first three entries are reserved.
867 this->got_plt_->set_current_data_size(3 * 8);
868
869 if (!is_got_plt_relro)
870 {
871 // Those bytes can go into the relro segment.
872 layout->increase_relro(3 * 8);
873 }
874
875 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
876 this->global_offset_table_ =
877 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
878 Symbol_table::PREDEFINED,
879 this->got_plt_,
880 0, 0, elfcpp::STT_OBJECT,
881 elfcpp::STB_LOCAL,
882 elfcpp::STV_HIDDEN, 0,
883 false, false);
884
885 // If there are any IRELATIVE relocations, they get GOT entries
886 // in .got.plt after the jump slot entries.
887 this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT");
888 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
889 (elfcpp::SHF_ALLOC
890 | elfcpp::SHF_WRITE),
891 this->got_irelative_,
892 got_plt_order, is_got_plt_relro);
893
894 // If there are any TLSDESC relocations, they get GOT entries in
895 // .got.plt after the jump slot and IRELATIVE entries.
896 this->got_tlsdesc_ = new Output_data_got<64, false>();
897 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
898 (elfcpp::SHF_ALLOC
899 | elfcpp::SHF_WRITE),
900 this->got_tlsdesc_,
901 got_plt_order, is_got_plt_relro);
902 }
903
904 return this->got_;
905 }
906
907 // Get the dynamic reloc section, creating it if necessary.
908
909 Target_x86_64::Reloc_section*
910 Target_x86_64::rela_dyn_section(Layout* layout)
911 {
912 if (this->rela_dyn_ == NULL)
913 {
914 gold_assert(layout != NULL);
915 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
916 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
917 elfcpp::SHF_ALLOC, this->rela_dyn_,
918 ORDER_DYNAMIC_RELOCS, false);
919 }
920 return this->rela_dyn_;
921 }
922
923 // Get the section to use for IRELATIVE relocs, creating it if
924 // necessary. These go in .rela.dyn, but only after all other dynamic
925 // relocations. They need to follow the other dynamic relocations so
926 // that they can refer to global variables initialized by those
927 // relocs.
928
929 Target_x86_64::Reloc_section*
930 Target_x86_64::rela_irelative_section(Layout* layout)
931 {
932 if (this->rela_irelative_ == NULL)
933 {
934 // Make sure we have already created the dynamic reloc section.
935 this->rela_dyn_section(layout);
936 this->rela_irelative_ = new Reloc_section(false);
937 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
938 elfcpp::SHF_ALLOC, this->rela_irelative_,
939 ORDER_DYNAMIC_RELOCS, false);
940 gold_assert(this->rela_dyn_->output_section()
941 == this->rela_irelative_->output_section());
942 }
943 return this->rela_irelative_;
944 }
945
946 // Initialize the PLT section.
947
948 void
949 Output_data_plt_x86_64::init(Layout* layout)
950 {
951 this->rel_ = new Reloc_section(false);
952 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
953 elfcpp::SHF_ALLOC, this->rel_,
954 ORDER_DYNAMIC_PLT_RELOCS, false);
955
956 // Add unwind information if requested.
957 if (parameters->options().ld_generated_unwind_info())
958 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
959 plt_eh_frame_fde, plt_eh_frame_fde_size);
960 }
961
962 void
963 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
964 {
965 os->set_entsize(plt_entry_size);
966 }
967
968 // Add an entry to the PLT.
969
970 void
971 Output_data_plt_x86_64::add_entry(Symbol_table* symtab, Layout* layout,
972 Symbol* gsym)
973 {
974 gold_assert(!gsym->has_plt_offset());
975
976 unsigned int plt_index;
977 off_t plt_offset;
978 section_offset_type got_offset;
979
980 unsigned int* pcount;
981 unsigned int offset;
982 unsigned int reserved;
983 Output_data_space* got;
984 if (gsym->type() == elfcpp::STT_GNU_IFUNC
985 && gsym->can_use_relative_reloc(false))
986 {
987 pcount = &this->irelative_count_;
988 offset = 0;
989 reserved = 0;
990 got = this->got_irelative_;
991 }
992 else
993 {
994 pcount = &this->count_;
995 offset = 1;
996 reserved = 3;
997 got = this->got_plt_;
998 }
999
1000 if (!this->is_data_size_valid())
1001 {
1002 // Note that when setting the PLT offset for a non-IRELATIVE
1003 // entry we skip the initial reserved PLT entry.
1004 plt_index = *pcount + offset;
1005 plt_offset = plt_index * plt_entry_size;
1006
1007 ++*pcount;
1008
1009 got_offset = (plt_index - offset + reserved) * 8;
1010 gold_assert(got_offset == got->current_data_size());
1011
1012 // Every PLT entry needs a GOT entry which points back to the PLT
1013 // entry (this will be changed by the dynamic linker, normally
1014 // lazily when the function is called).
1015 got->set_current_data_size(got_offset + 8);
1016 }
1017 else
1018 {
1019 // FIXME: This is probably not correct for IRELATIVE relocs.
1020
1021 // For incremental updates, find an available slot.
1022 plt_offset = this->free_list_.allocate(plt_entry_size, plt_entry_size, 0);
1023 if (plt_offset == -1)
1024 gold_fallback(_("out of patch space (PLT);"
1025 " relink with --incremental-full"));
1026
1027 // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset
1028 // can be calculated from the PLT index, adjusting for the three
1029 // reserved entries at the beginning of the GOT.
1030 plt_index = plt_offset / plt_entry_size - 1;
1031 got_offset = (plt_index - offset + reserved) * 8;
1032 }
1033
1034 gsym->set_plt_offset(plt_offset);
1035
1036 // Every PLT entry needs a reloc.
1037 this->add_relocation(symtab, layout, gsym, got_offset);
1038
1039 // Note that we don't need to save the symbol. The contents of the
1040 // PLT are independent of which symbols are used. The symbols only
1041 // appear in the relocations.
1042 }
1043
1044 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1045 // the PLT offset.
1046
1047 unsigned int
1048 Output_data_plt_x86_64::add_local_ifunc_entry(
1049 Symbol_table* symtab,
1050 Layout* layout,
1051 Sized_relobj_file<64, false>* relobj,
1052 unsigned int local_sym_index)
1053 {
1054 unsigned int plt_offset = this->irelative_count_ * plt_entry_size;
1055 ++this->irelative_count_;
1056
1057 section_offset_type got_offset = this->got_irelative_->current_data_size();
1058
1059 // Every PLT entry needs a GOT entry which points back to the PLT
1060 // entry.
1061 this->got_irelative_->set_current_data_size(got_offset + 8);
1062
1063 // Every PLT entry needs a reloc.
1064 Reloc_section* rela = this->rela_irelative(symtab, layout);
1065 rela->add_symbolless_local_addend(relobj, local_sym_index,
1066 elfcpp::R_X86_64_IRELATIVE,
1067 this->got_irelative_, got_offset, 0);
1068
1069 return plt_offset;
1070 }
1071
1072 // Add the relocation for a PLT entry.
1073
1074 void
1075 Output_data_plt_x86_64::add_relocation(Symbol_table* symtab, Layout* layout,
1076 Symbol* gsym, unsigned int got_offset)
1077 {
1078 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1079 && gsym->can_use_relative_reloc(false))
1080 {
1081 Reloc_section* rela = this->rela_irelative(symtab, layout);
1082 rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
1083 this->got_irelative_, got_offset, 0);
1084 }
1085 else
1086 {
1087 gsym->set_needs_dynsym_entry();
1088 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
1089 got_offset, 0);
1090 }
1091 }
1092
1093 // Return where the TLSDESC relocations should go, creating it if
1094 // necessary. These follow the JUMP_SLOT relocations.
1095
1096 Output_data_plt_x86_64::Reloc_section*
1097 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
1098 {
1099 if (this->tlsdesc_rel_ == NULL)
1100 {
1101 this->tlsdesc_rel_ = new Reloc_section(false);
1102 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1103 elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
1104 ORDER_DYNAMIC_PLT_RELOCS, false);
1105 gold_assert(this->tlsdesc_rel_->output_section()
1106 == this->rel_->output_section());
1107 }
1108 return this->tlsdesc_rel_;
1109 }
1110
1111 // Return where the IRELATIVE relocations should go in the PLT. These
1112 // follow the JUMP_SLOT and the TLSDESC relocations.
1113
1114 Output_data_plt_x86_64::Reloc_section*
1115 Output_data_plt_x86_64::rela_irelative(Symbol_table* symtab, Layout* layout)
1116 {
1117 if (this->irelative_rel_ == NULL)
1118 {
1119 // Make sure we have a place for the TLSDESC relocations, in
1120 // case we see any later on.
1121 this->rela_tlsdesc(layout);
1122 this->irelative_rel_ = new Reloc_section(false);
1123 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1124 elfcpp::SHF_ALLOC, this->irelative_rel_,
1125 ORDER_DYNAMIC_PLT_RELOCS, false);
1126 gold_assert(this->irelative_rel_->output_section()
1127 == this->rel_->output_section());
1128
1129 if (parameters->doing_static_link())
1130 {
1131 // A statically linked executable will only have a .rela.plt
1132 // section to hold R_X86_64_IRELATIVE relocs for
1133 // STT_GNU_IFUNC symbols. The library will use these
1134 // symbols to locate the IRELATIVE relocs at program startup
1135 // time.
1136 symtab->define_in_output_data("__rela_iplt_start", NULL,
1137 Symbol_table::PREDEFINED,
1138 this->irelative_rel_, 0, 0,
1139 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1140 elfcpp::STV_HIDDEN, 0, false, true);
1141 symtab->define_in_output_data("__rela_iplt_end", NULL,
1142 Symbol_table::PREDEFINED,
1143 this->irelative_rel_, 0, 0,
1144 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1145 elfcpp::STV_HIDDEN, 0, true, true);
1146 }
1147 }
1148 return this->irelative_rel_;
1149 }
1150
1151 // Return the PLT address to use for a global symbol.
1152
1153 uint64_t
1154 Output_data_plt_x86_64::address_for_global(const Symbol* gsym)
1155 {
1156 uint64_t offset = 0;
1157 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1158 && gsym->can_use_relative_reloc(false))
1159 offset = (this->count_ + 1) * plt_entry_size;
1160 return this->address() + offset;
1161 }
1162
1163 // Return the PLT address to use for a local symbol. These are always
1164 // IRELATIVE relocs.
1165
1166 uint64_t
1167 Output_data_plt_x86_64::address_for_local(const Relobj*, unsigned int)
1168 {
1169 return this->address() + (this->count_ + 1) * plt_entry_size;
1170 }
1171
1172 // Set the final size.
1173 void
1174 Output_data_plt_x86_64::set_final_data_size()
1175 {
1176 unsigned int count = this->count_ + this->irelative_count_;
1177 if (this->has_tlsdesc_entry())
1178 ++count;
1179 this->set_data_size((count + 1) * plt_entry_size);
1180 }
1181
1182 // The first entry in the PLT for an executable.
1183
1184 const unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
1185 {
1186 // From AMD64 ABI Draft 0.98, page 76
1187 0xff, 0x35, // pushq contents of memory address
1188 0, 0, 0, 0, // replaced with address of .got + 8
1189 0xff, 0x25, // jmp indirect
1190 0, 0, 0, 0, // replaced with address of .got + 16
1191 0x90, 0x90, 0x90, 0x90 // noop (x4)
1192 };
1193
1194 // Subsequent entries in the PLT for an executable.
1195
1196 const unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
1197 {
1198 // From AMD64 ABI Draft 0.98, page 76
1199 0xff, 0x25, // jmpq indirect
1200 0, 0, 0, 0, // replaced with address of symbol in .got
1201 0x68, // pushq immediate
1202 0, 0, 0, 0, // replaced with offset into relocation table
1203 0xe9, // jmpq relative
1204 0, 0, 0, 0 // replaced with offset to start of .plt
1205 };
1206
1207 // The reserved TLSDESC entry in the PLT for an executable.
1208
1209 const unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
1210 {
1211 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
1212 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
1213 0xff, 0x35, // pushq x(%rip)
1214 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
1215 0xff, 0x25, // jmpq *y(%rip)
1216 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
1217 0x0f, 0x1f, // nop
1218 0x40, 0
1219 };
1220
1221 // The .eh_frame unwind information for the PLT.
1222
1223 const unsigned char
1224 Output_data_plt_x86_64::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1225 {
1226 1, // CIE version.
1227 'z', // Augmentation: augmentation size included.
1228 'R', // Augmentation: FDE encoding included.
1229 '\0', // End of augmentation string.
1230 1, // Code alignment factor.
1231 0x78, // Data alignment factor.
1232 16, // Return address column.
1233 1, // Augmentation size.
1234 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1235 | elfcpp::DW_EH_PE_sdata4),
1236 elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8.
1237 elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8.
1238 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1239 elfcpp::DW_CFA_nop
1240 };
1241
1242 const unsigned char
1243 Output_data_plt_x86_64::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1244 {
1245 0, 0, 0, 0, // Replaced with offset to .plt.
1246 0, 0, 0, 0, // Replaced with size of .plt.
1247 0, // Augmentation size.
1248 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
1249 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1250 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
1251 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1252 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1253 11, // Block length.
1254 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
1255 elfcpp::DW_OP_breg16, 0, // Push %rip.
1256 elfcpp::DW_OP_lit15, // Push 0xf.
1257 elfcpp::DW_OP_and, // & (%rip & 0xf).
1258 elfcpp::DW_OP_lit11, // Push 0xb.
1259 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb)
1260 elfcpp::DW_OP_lit3, // Push 3.
1261 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3)
1262 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8
1263 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1264 elfcpp::DW_CFA_nop,
1265 elfcpp::DW_CFA_nop,
1266 elfcpp::DW_CFA_nop
1267 };
1268
1269 // Write out the PLT. This uses the hand-coded instructions above,
1270 // and adjusts them as needed. This is specified by the AMD64 ABI.
1271
1272 void
1273 Output_data_plt_x86_64::do_write(Output_file* of)
1274 {
1275 const off_t offset = this->offset();
1276 const section_size_type oview_size =
1277 convert_to_section_size_type(this->data_size());
1278 unsigned char* const oview = of->get_output_view(offset, oview_size);
1279
1280 const off_t got_file_offset = this->got_plt_->offset();
1281 gold_assert(parameters->incremental_update()
1282 || (got_file_offset + this->got_plt_->data_size()
1283 == this->got_irelative_->offset()));
1284 const section_size_type got_size =
1285 convert_to_section_size_type(this->got_plt_->data_size()
1286 + this->got_irelative_->data_size());
1287 unsigned char* const got_view = of->get_output_view(got_file_offset,
1288 got_size);
1289
1290 unsigned char* pov = oview;
1291
1292 // The base address of the .plt section.
1293 elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
1294 // The base address of the .got section.
1295 elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
1296 // The base address of the PLT portion of the .got section,
1297 // which is where the GOT pointer will point, and where the
1298 // three reserved GOT entries are located.
1299 elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
1300
1301 memcpy(pov, first_plt_entry, plt_entry_size);
1302 // We do a jmp relative to the PC at the end of this instruction.
1303 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1304 (got_address + 8
1305 - (plt_address + 6)));
1306 elfcpp::Swap<32, false>::writeval(pov + 8,
1307 (got_address + 16
1308 - (plt_address + 12)));
1309 pov += plt_entry_size;
1310
1311 unsigned char* got_pov = got_view;
1312
1313 // The first entry in the GOT is the address of the .dynamic section
1314 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1315 // We saved space for them when we created the section in
1316 // Target_x86_64::got_section.
1317 Output_section* dynamic = this->layout_->dynamic_section();
1318 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1319 elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr);
1320 got_pov += 8;
1321 memset(got_pov, 0, 16);
1322 got_pov += 16;
1323
1324 unsigned int plt_offset = plt_entry_size;
1325 unsigned int got_offset = 24;
1326 const unsigned int count = this->count_ + this->irelative_count_;
1327 for (unsigned int plt_index = 0;
1328 plt_index < count;
1329 ++plt_index,
1330 pov += plt_entry_size,
1331 got_pov += 8,
1332 plt_offset += plt_entry_size,
1333 got_offset += 8)
1334 {
1335 // Set and adjust the PLT entry itself.
1336 memcpy(pov, plt_entry, plt_entry_size);
1337 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1338 (got_address + got_offset
1339 - (plt_address + plt_offset
1340 + 6)));
1341
1342 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
1343 elfcpp::Swap<32, false>::writeval(pov + 12,
1344 - (plt_offset + plt_entry_size));
1345
1346 // Set the entry in the GOT.
1347 elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
1348 }
1349
1350 if (this->has_tlsdesc_entry())
1351 {
1352 // Set and adjust the reserved TLSDESC PLT entry.
1353 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
1354 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
1355 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1356 (got_address + 8
1357 - (plt_address + plt_offset
1358 + 6)));
1359 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
1360 (got_base
1361 + tlsdesc_got_offset
1362 - (plt_address + plt_offset
1363 + 12)));
1364 pov += plt_entry_size;
1365 }
1366
1367 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1368 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1369
1370 of->write_output_view(offset, oview_size, oview);
1371 of->write_output_view(got_file_offset, got_size, got_view);
1372 }
1373
1374 // Create the PLT section.
1375
1376 void
1377 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
1378 {
1379 if (this->plt_ == NULL)
1380 {
1381 // Create the GOT sections first.
1382 this->got_section(symtab, layout);
1383
1384 this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
1385 this->got_plt_,
1386 this->got_irelative_);
1387 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1388 (elfcpp::SHF_ALLOC
1389 | elfcpp::SHF_EXECINSTR),
1390 this->plt_, ORDER_PLT, false);
1391
1392 // Make the sh_info field of .rela.plt point to .plt.
1393 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1394 rela_plt_os->set_info_section(this->plt_->output_section());
1395 }
1396 }
1397
1398 // Return the section for TLSDESC relocations.
1399
1400 Target_x86_64::Reloc_section*
1401 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
1402 {
1403 return this->plt_section()->rela_tlsdesc(layout);
1404 }
1405
1406 // Create a PLT entry for a global symbol.
1407
1408 void
1409 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
1410 Symbol* gsym)
1411 {
1412 if (gsym->has_plt_offset())
1413 return;
1414
1415 if (this->plt_ == NULL)
1416 this->make_plt_section(symtab, layout);
1417
1418 this->plt_->add_entry(symtab, layout, gsym);
1419 }
1420
1421 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1422
1423 void
1424 Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1425 Sized_relobj_file<64, false>* relobj,
1426 unsigned int local_sym_index)
1427 {
1428 if (relobj->local_has_plt_offset(local_sym_index))
1429 return;
1430 if (this->plt_ == NULL)
1431 this->make_plt_section(symtab, layout);
1432 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1433 relobj,
1434 local_sym_index);
1435 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1436 }
1437
1438 // Return the number of entries in the PLT.
1439
1440 unsigned int
1441 Target_x86_64::plt_entry_count() const
1442 {
1443 if (this->plt_ == NULL)
1444 return 0;
1445 return this->plt_->entry_count();
1446 }
1447
1448 // Return the offset of the first non-reserved PLT entry.
1449
1450 unsigned int
1451 Target_x86_64::first_plt_entry_offset() const
1452 {
1453 return Output_data_plt_x86_64::first_plt_entry_offset();
1454 }
1455
1456 // Return the size of each PLT entry.
1457
1458 unsigned int
1459 Target_x86_64::plt_entry_size() const
1460 {
1461 return Output_data_plt_x86_64::get_plt_entry_size();
1462 }
1463
1464 // Create the GOT and PLT sections for an incremental update.
1465
1466 Output_data_got<64, false>*
1467 Target_x86_64::init_got_plt_for_update(Symbol_table* symtab,
1468 Layout* layout,
1469 unsigned int got_count,
1470 unsigned int plt_count)
1471 {
1472 gold_assert(this->got_ == NULL);
1473
1474 this->got_ = new Output_data_got<64, false>(got_count * 8);
1475 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
1476 (elfcpp::SHF_ALLOC
1477 | elfcpp::SHF_WRITE),
1478 this->got_, ORDER_RELRO_LAST,
1479 true);
1480
1481 // Add the three reserved entries.
1482 this->got_plt_ = new Output_data_space((plt_count + 3) * 8, 8, "** GOT PLT");
1483 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1484 (elfcpp::SHF_ALLOC
1485 | elfcpp::SHF_WRITE),
1486 this->got_plt_, ORDER_NON_RELRO_FIRST,
1487 false);
1488
1489 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
1490 this->global_offset_table_ =
1491 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
1492 Symbol_table::PREDEFINED,
1493 this->got_plt_,
1494 0, 0, elfcpp::STT_OBJECT,
1495 elfcpp::STB_LOCAL,
1496 elfcpp::STV_HIDDEN, 0,
1497 false, false);
1498
1499 // If there are any TLSDESC relocations, they get GOT entries in
1500 // .got.plt after the jump slot entries.
1501 // FIXME: Get the count for TLSDESC entries.
1502 this->got_tlsdesc_ = new Output_data_got<64, false>(0);
1503 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1504 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1505 this->got_tlsdesc_,
1506 ORDER_NON_RELRO_FIRST, false);
1507
1508 // If there are any IRELATIVE relocations, they get GOT entries in
1509 // .got.plt after the jump slot and TLSDESC entries.
1510 this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT");
1511 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1512 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1513 this->got_irelative_,
1514 ORDER_NON_RELRO_FIRST, false);
1515
1516 // Create the PLT section.
1517 this->plt_ = new Output_data_plt_x86_64(layout, this->got_, this->got_plt_,
1518 this->got_irelative_, plt_count);
1519 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1520 elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR,
1521 this->plt_, ORDER_PLT, false);
1522
1523 // Make the sh_info field of .rela.plt point to .plt.
1524 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1525 rela_plt_os->set_info_section(this->plt_->output_section());
1526
1527 // Create the rela_dyn section.
1528 this->rela_dyn_section(layout);
1529
1530 return this->got_;
1531 }
1532
1533 // Reserve a GOT entry for a local symbol, and regenerate any
1534 // necessary dynamic relocations.
1535
1536 void
1537 Target_x86_64::reserve_local_got_entry(
1538 unsigned int got_index,
1539 Sized_relobj<64, false>* obj,
1540 unsigned int r_sym,
1541 unsigned int got_type)
1542 {
1543 unsigned int got_offset = got_index * 8;
1544 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1545
1546 this->got_->reserve_local(got_index, obj, r_sym, got_type);
1547 switch (got_type)
1548 {
1549 case GOT_TYPE_STANDARD:
1550 if (parameters->options().output_is_position_independent())
1551 rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
1552 this->got_, got_offset, 0, false);
1553 break;
1554 case GOT_TYPE_TLS_OFFSET:
1555 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
1556 this->got_, got_offset, 0);
1557 break;
1558 case GOT_TYPE_TLS_PAIR:
1559 this->got_->reserve_slot(got_index + 1);
1560 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64,
1561 this->got_, got_offset, 0);
1562 break;
1563 case GOT_TYPE_TLS_DESC:
1564 gold_fatal(_("TLS_DESC not yet supported for incremental linking"));
1565 // this->got_->reserve_slot(got_index + 1);
1566 // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1567 // this->got_, got_offset, 0);
1568 break;
1569 default:
1570 gold_unreachable();
1571 }
1572 }
1573
1574 // Reserve a GOT entry for a global symbol, and regenerate any
1575 // necessary dynamic relocations.
1576
1577 void
1578 Target_x86_64::reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
1579 unsigned int got_type)
1580 {
1581 unsigned int got_offset = got_index * 8;
1582 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1583
1584 this->got_->reserve_global(got_index, gsym, got_type);
1585 switch (got_type)
1586 {
1587 case GOT_TYPE_STANDARD:
1588 if (!gsym->final_value_is_known())
1589 {
1590 if (gsym->is_from_dynobj()
1591 || gsym->is_undefined()
1592 || gsym->is_preemptible()
1593 || gsym->type() == elfcpp::STT_GNU_IFUNC)
1594 rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT,
1595 this->got_, got_offset, 0);
1596 else
1597 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1598 this->got_, got_offset, 0);
1599 }
1600 break;
1601 case GOT_TYPE_TLS_OFFSET:
1602 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64,
1603 this->got_, got_offset, 0);
1604 break;
1605 case GOT_TYPE_TLS_PAIR:
1606 this->got_->reserve_slot(got_index + 1);
1607 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64,
1608 this->got_, got_offset, 0);
1609 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64,
1610 this->got_, got_offset + 8, 0);
1611 break;
1612 case GOT_TYPE_TLS_DESC:
1613 this->got_->reserve_slot(got_index + 1);
1614 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC,
1615 this->got_, got_offset, 0);
1616 break;
1617 default:
1618 gold_unreachable();
1619 }
1620 }
1621
1622 // Register an existing PLT entry for a global symbol.
1623
1624 void
1625 Target_x86_64::register_global_plt_entry(Symbol_table* symtab,
1626 Layout* layout,
1627 unsigned int plt_index,
1628 Symbol* gsym)
1629 {
1630 gold_assert(this->plt_ != NULL);
1631 gold_assert(!gsym->has_plt_offset());
1632
1633 this->plt_->reserve_slot(plt_index);
1634
1635 gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
1636
1637 unsigned int got_offset = (plt_index + 3) * 8;
1638 this->plt_->add_relocation(symtab, layout, gsym, got_offset);
1639 }
1640
1641 // Force a COPY relocation for a given symbol.
1642
1643 void
1644 Target_x86_64::emit_copy_reloc(
1645 Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset)
1646 {
1647 this->copy_relocs_.emit_copy_reloc(symtab,
1648 symtab->get_sized_symbol<64>(sym),
1649 os,
1650 offset,
1651 this->rela_dyn_section(NULL));
1652 }
1653
1654 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1655
1656 void
1657 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1658 {
1659 if (this->tls_base_symbol_defined_)
1660 return;
1661
1662 Output_segment* tls_segment = layout->tls_segment();
1663 if (tls_segment != NULL)
1664 {
1665 bool is_exec = parameters->options().output_is_executable();
1666 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1667 Symbol_table::PREDEFINED,
1668 tls_segment, 0, 0,
1669 elfcpp::STT_TLS,
1670 elfcpp::STB_LOCAL,
1671 elfcpp::STV_HIDDEN, 0,
1672 (is_exec
1673 ? Symbol::SEGMENT_END
1674 : Symbol::SEGMENT_START),
1675 true);
1676 }
1677 this->tls_base_symbol_defined_ = true;
1678 }
1679
1680 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1681
1682 void
1683 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
1684 Layout* layout)
1685 {
1686 if (this->plt_ == NULL)
1687 this->make_plt_section(symtab, layout);
1688
1689 if (!this->plt_->has_tlsdesc_entry())
1690 {
1691 // Allocate the TLSDESC_GOT entry.
1692 Output_data_got<64, false>* got = this->got_section(symtab, layout);
1693 unsigned int got_offset = got->add_constant(0);
1694
1695 // Allocate the TLSDESC_PLT entry.
1696 this->plt_->reserve_tlsdesc_entry(got_offset);
1697 }
1698 }
1699
1700 // Create a GOT entry for the TLS module index.
1701
1702 unsigned int
1703 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1704 Sized_relobj_file<64, false>* object)
1705 {
1706 if (this->got_mod_index_offset_ == -1U)
1707 {
1708 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1709 Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1710 Output_data_got<64, false>* got = this->got_section(symtab, layout);
1711 unsigned int got_offset = got->add_constant(0);
1712 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1713 got_offset, 0);
1714 got->add_constant(0);
1715 this->got_mod_index_offset_ = got_offset;
1716 }
1717 return this->got_mod_index_offset_;
1718 }
1719
1720 // Optimize the TLS relocation type based on what we know about the
1721 // symbol. IS_FINAL is true if the final address of this symbol is
1722 // known at link time.
1723
1724 tls::Tls_optimization
1725 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1726 {
1727 // If we are generating a shared library, then we can't do anything
1728 // in the linker.
1729 if (parameters->options().shared())
1730 return tls::TLSOPT_NONE;
1731
1732 switch (r_type)
1733 {
1734 case elfcpp::R_X86_64_TLSGD:
1735 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1736 case elfcpp::R_X86_64_TLSDESC_CALL:
1737 // These are General-Dynamic which permits fully general TLS
1738 // access. Since we know that we are generating an executable,
1739 // we can convert this to Initial-Exec. If we also know that
1740 // this is a local symbol, we can further switch to Local-Exec.
1741 if (is_final)
1742 return tls::TLSOPT_TO_LE;
1743 return tls::TLSOPT_TO_IE;
1744
1745 case elfcpp::R_X86_64_TLSLD:
1746 // This is Local-Dynamic, which refers to a local symbol in the
1747 // dynamic TLS block. Since we know that we generating an
1748 // executable, we can switch to Local-Exec.
1749 return tls::TLSOPT_TO_LE;
1750
1751 case elfcpp::R_X86_64_DTPOFF32:
1752 case elfcpp::R_X86_64_DTPOFF64:
1753 // Another Local-Dynamic reloc.
1754 return tls::TLSOPT_TO_LE;
1755
1756 case elfcpp::R_X86_64_GOTTPOFF:
1757 // These are Initial-Exec relocs which get the thread offset
1758 // from the GOT. If we know that we are linking against the
1759 // local symbol, we can switch to Local-Exec, which links the
1760 // thread offset into the instruction.
1761 if (is_final)
1762 return tls::TLSOPT_TO_LE;
1763 return tls::TLSOPT_NONE;
1764
1765 case elfcpp::R_X86_64_TPOFF32:
1766 // When we already have Local-Exec, there is nothing further we
1767 // can do.
1768 return tls::TLSOPT_NONE;
1769
1770 default:
1771 gold_unreachable();
1772 }
1773 }
1774
1775 // Get the Reference_flags for a particular relocation.
1776
1777 int
1778 Target_x86_64::Scan::get_reference_flags(unsigned int r_type)
1779 {
1780 switch (r_type)
1781 {
1782 case elfcpp::R_X86_64_NONE:
1783 case elfcpp::R_X86_64_GNU_VTINHERIT:
1784 case elfcpp::R_X86_64_GNU_VTENTRY:
1785 case elfcpp::R_X86_64_GOTPC32:
1786 case elfcpp::R_X86_64_GOTPC64:
1787 // No symbol reference.
1788 return 0;
1789
1790 case elfcpp::R_X86_64_64:
1791 case elfcpp::R_X86_64_32:
1792 case elfcpp::R_X86_64_32S:
1793 case elfcpp::R_X86_64_16:
1794 case elfcpp::R_X86_64_8:
1795 return Symbol::ABSOLUTE_REF;
1796
1797 case elfcpp::R_X86_64_PC64:
1798 case elfcpp::R_X86_64_PC32:
1799 case elfcpp::R_X86_64_PC16:
1800 case elfcpp::R_X86_64_PC8:
1801 case elfcpp::R_X86_64_GOTOFF64:
1802 return Symbol::RELATIVE_REF;
1803
1804 case elfcpp::R_X86_64_PLT32:
1805 case elfcpp::R_X86_64_PLTOFF64:
1806 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1807
1808 case elfcpp::R_X86_64_GOT64:
1809 case elfcpp::R_X86_64_GOT32:
1810 case elfcpp::R_X86_64_GOTPCREL64:
1811 case elfcpp::R_X86_64_GOTPCREL:
1812 case elfcpp::R_X86_64_GOTPLT64:
1813 // Absolute in GOT.
1814 return Symbol::ABSOLUTE_REF;
1815
1816 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
1817 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
1818 case elfcpp::R_X86_64_TLSDESC_CALL:
1819 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
1820 case elfcpp::R_X86_64_DTPOFF32:
1821 case elfcpp::R_X86_64_DTPOFF64:
1822 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
1823 case elfcpp::R_X86_64_TPOFF32: // Local-exec
1824 return Symbol::TLS_REF;
1825
1826 case elfcpp::R_X86_64_COPY:
1827 case elfcpp::R_X86_64_GLOB_DAT:
1828 case elfcpp::R_X86_64_JUMP_SLOT:
1829 case elfcpp::R_X86_64_RELATIVE:
1830 case elfcpp::R_X86_64_IRELATIVE:
1831 case elfcpp::R_X86_64_TPOFF64:
1832 case elfcpp::R_X86_64_DTPMOD64:
1833 case elfcpp::R_X86_64_TLSDESC:
1834 case elfcpp::R_X86_64_SIZE32:
1835 case elfcpp::R_X86_64_SIZE64:
1836 default:
1837 // Not expected. We will give an error later.
1838 return 0;
1839 }
1840 }
1841
1842 // Report an unsupported relocation against a local symbol.
1843
1844 void
1845 Target_x86_64::Scan::unsupported_reloc_local(
1846 Sized_relobj_file<64, false>* object,
1847 unsigned int r_type)
1848 {
1849 gold_error(_("%s: unsupported reloc %u against local symbol"),
1850 object->name().c_str(), r_type);
1851 }
1852
1853 // We are about to emit a dynamic relocation of type R_TYPE. If the
1854 // dynamic linker does not support it, issue an error. The GNU linker
1855 // only issues a non-PIC error for an allocated read-only section.
1856 // Here we know the section is allocated, but we don't know that it is
1857 // read-only. But we check for all the relocation types which the
1858 // glibc dynamic linker supports, so it seems appropriate to issue an
1859 // error even if the section is not read-only. If GSYM is not NULL,
1860 // it is the symbol the relocation is against; if it is NULL, the
1861 // relocation is against a local symbol.
1862
1863 void
1864 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type,
1865 Symbol* gsym)
1866 {
1867 switch (r_type)
1868 {
1869 // These are the relocation types supported by glibc for x86_64
1870 // which should always work.
1871 case elfcpp::R_X86_64_RELATIVE:
1872 case elfcpp::R_X86_64_IRELATIVE:
1873 case elfcpp::R_X86_64_GLOB_DAT:
1874 case elfcpp::R_X86_64_JUMP_SLOT:
1875 case elfcpp::R_X86_64_DTPMOD64:
1876 case elfcpp::R_X86_64_DTPOFF64:
1877 case elfcpp::R_X86_64_TPOFF64:
1878 case elfcpp::R_X86_64_64:
1879 case elfcpp::R_X86_64_COPY:
1880 return;
1881
1882 // glibc supports these reloc types, but they can overflow.
1883 case elfcpp::R_X86_64_PC32:
1884 // A PC relative reference is OK against a local symbol or if
1885 // the symbol is defined locally.
1886 if (gsym == NULL
1887 || (!gsym->is_from_dynobj()
1888 && !gsym->is_undefined()
1889 && !gsym->is_preemptible()))
1890 return;
1891 /* Fall through. */
1892 case elfcpp::R_X86_64_32:
1893 if (this->issued_non_pic_error_)
1894 return;
1895 gold_assert(parameters->options().output_is_position_independent());
1896 if (gsym == NULL)
1897 object->error(_("requires dynamic R_X86_64_32 reloc which may "
1898 "overflow at runtime; recompile with -fPIC"));
1899 else
1900 object->error(_("requires dynamic %s reloc against '%s' which may "
1901 "overflow at runtime; recompile with -fPIC"),
1902 (r_type == elfcpp::R_X86_64_32
1903 ? "R_X86_64_32"
1904 : "R_X86_64_PC32"),
1905 gsym->name());
1906 this->issued_non_pic_error_ = true;
1907 return;
1908
1909 default:
1910 // This prevents us from issuing more than one error per reloc
1911 // section. But we can still wind up issuing more than one
1912 // error per object file.
1913 if (this->issued_non_pic_error_)
1914 return;
1915 gold_assert(parameters->options().output_is_position_independent());
1916 object->error(_("requires unsupported dynamic reloc %u; "
1917 "recompile with -fPIC"),
1918 r_type);
1919 this->issued_non_pic_error_ = true;
1920 return;
1921
1922 case elfcpp::R_X86_64_NONE:
1923 gold_unreachable();
1924 }
1925 }
1926
1927 // Return whether we need to make a PLT entry for a relocation of the
1928 // given type against a STT_GNU_IFUNC symbol.
1929
1930 bool
1931 Target_x86_64::Scan::reloc_needs_plt_for_ifunc(
1932 Sized_relobj_file<64, false>* object,
1933 unsigned int r_type)
1934 {
1935 int flags = Scan::get_reference_flags(r_type);
1936 if (flags & Symbol::TLS_REF)
1937 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1938 object->name().c_str(), r_type);
1939 return flags != 0;
1940 }
1941
1942 // Scan a relocation for a local symbol.
1943
1944 inline void
1945 Target_x86_64::Scan::local(Symbol_table* symtab,
1946 Layout* layout,
1947 Target_x86_64* target,
1948 Sized_relobj_file<64, false>* object,
1949 unsigned int data_shndx,
1950 Output_section* output_section,
1951 const elfcpp::Rela<64, false>& reloc,
1952 unsigned int r_type,
1953 const elfcpp::Sym<64, false>& lsym)
1954 {
1955 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1956 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
1957 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
1958 {
1959 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1960 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1961 }
1962
1963 switch (r_type)
1964 {
1965 case elfcpp::R_X86_64_NONE:
1966 case elfcpp::R_X86_64_GNU_VTINHERIT:
1967 case elfcpp::R_X86_64_GNU_VTENTRY:
1968 break;
1969
1970 case elfcpp::R_X86_64_64:
1971 // If building a shared library (or a position-independent
1972 // executable), we need to create a dynamic relocation for this
1973 // location. The relocation applied at link time will apply the
1974 // link-time value, so we flag the location with an
1975 // R_X86_64_RELATIVE relocation so the dynamic loader can
1976 // relocate it easily.
1977 if (parameters->options().output_is_position_independent())
1978 {
1979 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1980 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1981 rela_dyn->add_local_relative(object, r_sym,
1982 elfcpp::R_X86_64_RELATIVE,
1983 output_section, data_shndx,
1984 reloc.get_r_offset(),
1985 reloc.get_r_addend(), is_ifunc);
1986 }
1987 break;
1988
1989 case elfcpp::R_X86_64_32:
1990 case elfcpp::R_X86_64_32S:
1991 case elfcpp::R_X86_64_16:
1992 case elfcpp::R_X86_64_8:
1993 // If building a shared library (or a position-independent
1994 // executable), we need to create a dynamic relocation for this
1995 // location. We can't use an R_X86_64_RELATIVE relocation
1996 // because that is always a 64-bit relocation.
1997 if (parameters->options().output_is_position_independent())
1998 {
1999 this->check_non_pic(object, r_type, NULL);
2000
2001 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2002 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
2003 if (lsym.get_st_type() != elfcpp::STT_SECTION)
2004 rela_dyn->add_local(object, r_sym, r_type, output_section,
2005 data_shndx, reloc.get_r_offset(),
2006 reloc.get_r_addend());
2007 else
2008 {
2009 gold_assert(lsym.get_st_value() == 0);
2010 unsigned int shndx = lsym.get_st_shndx();
2011 bool is_ordinary;
2012 shndx = object->adjust_sym_shndx(r_sym, shndx,
2013 &is_ordinary);
2014 if (!is_ordinary)
2015 object->error(_("section symbol %u has bad shndx %u"),
2016 r_sym, shndx);
2017 else
2018 rela_dyn->add_local_section(object, shndx,
2019 r_type, output_section,
2020 data_shndx, reloc.get_r_offset(),
2021 reloc.get_r_addend());
2022 }
2023 }
2024 break;
2025
2026 case elfcpp::R_X86_64_PC64:
2027 case elfcpp::R_X86_64_PC32:
2028 case elfcpp::R_X86_64_PC16:
2029 case elfcpp::R_X86_64_PC8:
2030 break;
2031
2032 case elfcpp::R_X86_64_PLT32:
2033 // Since we know this is a local symbol, we can handle this as a
2034 // PC32 reloc.
2035 break;
2036
2037 case elfcpp::R_X86_64_GOTPC32:
2038 case elfcpp::R_X86_64_GOTOFF64:
2039 case elfcpp::R_X86_64_GOTPC64:
2040 case elfcpp::R_X86_64_PLTOFF64:
2041 // We need a GOT section.
2042 target->got_section(symtab, layout);
2043 // For PLTOFF64, we'd normally want a PLT section, but since we
2044 // know this is a local symbol, no PLT is needed.
2045 break;
2046
2047 case elfcpp::R_X86_64_GOT64:
2048 case elfcpp::R_X86_64_GOT32:
2049 case elfcpp::R_X86_64_GOTPCREL64:
2050 case elfcpp::R_X86_64_GOTPCREL:
2051 case elfcpp::R_X86_64_GOTPLT64:
2052 {
2053 // The symbol requires a GOT entry.
2054 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2055 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
2056
2057 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
2058 // lets function pointers compare correctly with shared
2059 // libraries. Otherwise we would need an IRELATIVE reloc.
2060 bool is_new;
2061 if (is_ifunc)
2062 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
2063 else
2064 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
2065 if (is_new)
2066 {
2067 // If we are generating a shared object, we need to add a
2068 // dynamic relocation for this symbol's GOT entry.
2069 if (parameters->options().output_is_position_independent())
2070 {
2071 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2072 // R_X86_64_RELATIVE assumes a 64-bit relocation.
2073 if (r_type != elfcpp::R_X86_64_GOT32)
2074 {
2075 unsigned int got_offset =
2076 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
2077 rela_dyn->add_local_relative(object, r_sym,
2078 elfcpp::R_X86_64_RELATIVE,
2079 got, got_offset, 0, is_ifunc);
2080 }
2081 else
2082 {
2083 this->check_non_pic(object, r_type, NULL);
2084
2085 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2086 rela_dyn->add_local(
2087 object, r_sym, r_type, got,
2088 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
2089 }
2090 }
2091 }
2092 // For GOTPLT64, we'd normally want a PLT section, but since
2093 // we know this is a local symbol, no PLT is needed.
2094 }
2095 break;
2096
2097 case elfcpp::R_X86_64_COPY:
2098 case elfcpp::R_X86_64_GLOB_DAT:
2099 case elfcpp::R_X86_64_JUMP_SLOT:
2100 case elfcpp::R_X86_64_RELATIVE:
2101 case elfcpp::R_X86_64_IRELATIVE:
2102 // These are outstanding tls relocs, which are unexpected when linking
2103 case elfcpp::R_X86_64_TPOFF64:
2104 case elfcpp::R_X86_64_DTPMOD64:
2105 case elfcpp::R_X86_64_TLSDESC:
2106 gold_error(_("%s: unexpected reloc %u in object file"),
2107 object->name().c_str(), r_type);
2108 break;
2109
2110 // These are initial tls relocs, which are expected when linking
2111 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2112 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2113 case elfcpp::R_X86_64_TLSDESC_CALL:
2114 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2115 case elfcpp::R_X86_64_DTPOFF32:
2116 case elfcpp::R_X86_64_DTPOFF64:
2117 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2118 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2119 {
2120 bool output_is_shared = parameters->options().shared();
2121 const tls::Tls_optimization optimized_type
2122 = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
2123 switch (r_type)
2124 {
2125 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2126 if (optimized_type == tls::TLSOPT_NONE)
2127 {
2128 // Create a pair of GOT entries for the module index and
2129 // dtv-relative offset.
2130 Output_data_got<64, false>* got
2131 = target->got_section(symtab, layout);
2132 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
2133 unsigned int shndx = lsym.get_st_shndx();
2134 bool is_ordinary;
2135 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
2136 if (!is_ordinary)
2137 object->error(_("local symbol %u has bad shndx %u"),
2138 r_sym, shndx);
2139 else
2140 got->add_local_pair_with_rela(object, r_sym,
2141 shndx,
2142 GOT_TYPE_TLS_PAIR,
2143 target->rela_dyn_section(layout),
2144 elfcpp::R_X86_64_DTPMOD64, 0);
2145 }
2146 else if (optimized_type != tls::TLSOPT_TO_LE)
2147 unsupported_reloc_local(object, r_type);
2148 break;
2149
2150 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2151 target->define_tls_base_symbol(symtab, layout);
2152 if (optimized_type == tls::TLSOPT_NONE)
2153 {
2154 // Create reserved PLT and GOT entries for the resolver.
2155 target->reserve_tlsdesc_entries(symtab, layout);
2156
2157 // Generate a double GOT entry with an
2158 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
2159 // is resolved lazily, so the GOT entry needs to be in
2160 // an area in .got.plt, not .got. Call got_section to
2161 // make sure the section has been created.
2162 target->got_section(symtab, layout);
2163 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2164 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
2165 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
2166 {
2167 unsigned int got_offset = got->add_constant(0);
2168 got->add_constant(0);
2169 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
2170 got_offset);
2171 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2172 // We store the arguments we need in a vector, and
2173 // use the index into the vector as the parameter
2174 // to pass to the target specific routines.
2175 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
2176 void* arg = reinterpret_cast<void*>(intarg);
2177 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
2178 got, got_offset, 0);
2179 }
2180 }
2181 else if (optimized_type != tls::TLSOPT_TO_LE)
2182 unsupported_reloc_local(object, r_type);
2183 break;
2184
2185 case elfcpp::R_X86_64_TLSDESC_CALL:
2186 break;
2187
2188 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2189 if (optimized_type == tls::TLSOPT_NONE)
2190 {
2191 // Create a GOT entry for the module index.
2192 target->got_mod_index_entry(symtab, layout, object);
2193 }
2194 else if (optimized_type != tls::TLSOPT_TO_LE)
2195 unsupported_reloc_local(object, r_type);
2196 break;
2197
2198 case elfcpp::R_X86_64_DTPOFF32:
2199 case elfcpp::R_X86_64_DTPOFF64:
2200 break;
2201
2202 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2203 layout->set_has_static_tls();
2204 if (optimized_type == tls::TLSOPT_NONE)
2205 {
2206 // Create a GOT entry for the tp-relative offset.
2207 Output_data_got<64, false>* got
2208 = target->got_section(symtab, layout);
2209 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
2210 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
2211 target->rela_dyn_section(layout),
2212 elfcpp::R_X86_64_TPOFF64);
2213 }
2214 else if (optimized_type != tls::TLSOPT_TO_LE)
2215 unsupported_reloc_local(object, r_type);
2216 break;
2217
2218 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2219 layout->set_has_static_tls();
2220 if (output_is_shared)
2221 unsupported_reloc_local(object, r_type);
2222 break;
2223
2224 default:
2225 gold_unreachable();
2226 }
2227 }
2228 break;
2229
2230 case elfcpp::R_X86_64_SIZE32:
2231 case elfcpp::R_X86_64_SIZE64:
2232 default:
2233 gold_error(_("%s: unsupported reloc %u against local symbol"),
2234 object->name().c_str(), r_type);
2235 break;
2236 }
2237 }
2238
2239
2240 // Report an unsupported relocation against a global symbol.
2241
2242 void
2243 Target_x86_64::Scan::unsupported_reloc_global(
2244 Sized_relobj_file<64, false>* object,
2245 unsigned int r_type,
2246 Symbol* gsym)
2247 {
2248 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2249 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2250 }
2251
2252 // Returns true if this relocation type could be that of a function pointer.
2253 inline bool
2254 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
2255 {
2256 switch (r_type)
2257 {
2258 case elfcpp::R_X86_64_64:
2259 case elfcpp::R_X86_64_32:
2260 case elfcpp::R_X86_64_32S:
2261 case elfcpp::R_X86_64_16:
2262 case elfcpp::R_X86_64_8:
2263 case elfcpp::R_X86_64_GOT64:
2264 case elfcpp::R_X86_64_GOT32:
2265 case elfcpp::R_X86_64_GOTPCREL64:
2266 case elfcpp::R_X86_64_GOTPCREL:
2267 case elfcpp::R_X86_64_GOTPLT64:
2268 {
2269 return true;
2270 }
2271 }
2272 return false;
2273 }
2274
2275 // For safe ICF, scan a relocation for a local symbol to check if it
2276 // corresponds to a function pointer being taken. In that case mark
2277 // the function whose pointer was taken as not foldable.
2278
2279 inline bool
2280 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
2281 Symbol_table* ,
2282 Layout* ,
2283 Target_x86_64* ,
2284 Sized_relobj_file<64, false>* ,
2285 unsigned int ,
2286 Output_section* ,
2287 const elfcpp::Rela<64, false>& ,
2288 unsigned int r_type,
2289 const elfcpp::Sym<64, false>&)
2290 {
2291 // When building a shared library, do not fold any local symbols as it is
2292 // not possible to distinguish pointer taken versus a call by looking at
2293 // the relocation types.
2294 return (parameters->options().shared()
2295 || possible_function_pointer_reloc(r_type));
2296 }
2297
2298 // For safe ICF, scan a relocation for a global symbol to check if it
2299 // corresponds to a function pointer being taken. In that case mark
2300 // the function whose pointer was taken as not foldable.
2301
2302 inline bool
2303 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
2304 Symbol_table*,
2305 Layout* ,
2306 Target_x86_64* ,
2307 Sized_relobj_file<64, false>* ,
2308 unsigned int ,
2309 Output_section* ,
2310 const elfcpp::Rela<64, false>& ,
2311 unsigned int r_type,
2312 Symbol* gsym)
2313 {
2314 // When building a shared library, do not fold symbols whose visibility
2315 // is hidden, internal or protected.
2316 return ((parameters->options().shared()
2317 && (gsym->visibility() == elfcpp::STV_INTERNAL
2318 || gsym->visibility() == elfcpp::STV_PROTECTED
2319 || gsym->visibility() == elfcpp::STV_HIDDEN))
2320 || possible_function_pointer_reloc(r_type));
2321 }
2322
2323 // Scan a relocation for a global symbol.
2324
2325 inline void
2326 Target_x86_64::Scan::global(Symbol_table* symtab,
2327 Layout* layout,
2328 Target_x86_64* target,
2329 Sized_relobj_file<64, false>* object,
2330 unsigned int data_shndx,
2331 Output_section* output_section,
2332 const elfcpp::Rela<64, false>& reloc,
2333 unsigned int r_type,
2334 Symbol* gsym)
2335 {
2336 // A STT_GNU_IFUNC symbol may require a PLT entry.
2337 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2338 && this->reloc_needs_plt_for_ifunc(object, r_type))
2339 target->make_plt_entry(symtab, layout, gsym);
2340
2341 switch (r_type)
2342 {
2343 case elfcpp::R_X86_64_NONE:
2344 case elfcpp::R_X86_64_GNU_VTINHERIT:
2345 case elfcpp::R_X86_64_GNU_VTENTRY:
2346 break;
2347
2348 case elfcpp::R_X86_64_64:
2349 case elfcpp::R_X86_64_32:
2350 case elfcpp::R_X86_64_32S:
2351 case elfcpp::R_X86_64_16:
2352 case elfcpp::R_X86_64_8:
2353 {
2354 // Make a PLT entry if necessary.
2355 if (gsym->needs_plt_entry())
2356 {
2357 target->make_plt_entry(symtab, layout, gsym);
2358 // Since this is not a PC-relative relocation, we may be
2359 // taking the address of a function. In that case we need to
2360 // set the entry in the dynamic symbol table to the address of
2361 // the PLT entry.
2362 if (gsym->is_from_dynobj() && !parameters->options().shared())
2363 gsym->set_needs_dynsym_value();
2364 }
2365 // Make a dynamic relocation if necessary.
2366 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2367 {
2368 if (gsym->may_need_copy_reloc())
2369 {
2370 target->copy_reloc(symtab, layout, object,
2371 data_shndx, output_section, gsym, reloc);
2372 }
2373 else if (r_type == elfcpp::R_X86_64_64
2374 && gsym->type() == elfcpp::STT_GNU_IFUNC
2375 && gsym->can_use_relative_reloc(false)
2376 && !gsym->is_from_dynobj()
2377 && !gsym->is_undefined()
2378 && !gsym->is_preemptible())
2379 {
2380 // Use an IRELATIVE reloc for a locally defined
2381 // STT_GNU_IFUNC symbol. This makes a function
2382 // address in a PIE executable match the address in a
2383 // shared library that it links against.
2384 Reloc_section* rela_dyn =
2385 target->rela_irelative_section(layout);
2386 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
2387 rela_dyn->add_symbolless_global_addend(gsym, r_type,
2388 output_section, object,
2389 data_shndx,
2390 reloc.get_r_offset(),
2391 reloc.get_r_addend());
2392 }
2393 else if (r_type == elfcpp::R_X86_64_64
2394 && gsym->can_use_relative_reloc(false))
2395 {
2396 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2397 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
2398 output_section, object,
2399 data_shndx,
2400 reloc.get_r_offset(),
2401 reloc.get_r_addend());
2402 }
2403 else
2404 {
2405 this->check_non_pic(object, r_type, gsym);
2406 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2407 rela_dyn->add_global(gsym, r_type, output_section, object,
2408 data_shndx, reloc.get_r_offset(),
2409 reloc.get_r_addend());
2410 }
2411 }
2412 }
2413 break;
2414
2415 case elfcpp::R_X86_64_PC64:
2416 case elfcpp::R_X86_64_PC32:
2417 case elfcpp::R_X86_64_PC16:
2418 case elfcpp::R_X86_64_PC8:
2419 {
2420 // Make a PLT entry if necessary.
2421 if (gsym->needs_plt_entry())
2422 target->make_plt_entry(symtab, layout, gsym);
2423 // Make a dynamic relocation if necessary.
2424 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2425 {
2426 if (gsym->may_need_copy_reloc())
2427 {
2428 target->copy_reloc(symtab, layout, object,
2429 data_shndx, output_section, gsym, reloc);
2430 }
2431 else
2432 {
2433 this->check_non_pic(object, r_type, gsym);
2434 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2435 rela_dyn->add_global(gsym, r_type, output_section, object,
2436 data_shndx, reloc.get_r_offset(),
2437 reloc.get_r_addend());
2438 }
2439 }
2440 }
2441 break;
2442
2443 case elfcpp::R_X86_64_GOT64:
2444 case elfcpp::R_X86_64_GOT32:
2445 case elfcpp::R_X86_64_GOTPCREL64:
2446 case elfcpp::R_X86_64_GOTPCREL:
2447 case elfcpp::R_X86_64_GOTPLT64:
2448 {
2449 // The symbol requires a GOT entry.
2450 Output_data_got<64, false>* got = target->got_section(symtab, layout);
2451 if (gsym->final_value_is_known())
2452 {
2453 // For a STT_GNU_IFUNC symbol we want the PLT address.
2454 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2455 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2456 else
2457 got->add_global(gsym, GOT_TYPE_STANDARD);
2458 }
2459 else
2460 {
2461 // If this symbol is not fully resolved, we need to add a
2462 // dynamic relocation for it.
2463 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2464
2465 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2466 //
2467 // 1) The symbol may be defined in some other module.
2468 //
2469 // 2) We are building a shared library and this is a
2470 // protected symbol; using GLOB_DAT means that the dynamic
2471 // linker can use the address of the PLT in the main
2472 // executable when appropriate so that function address
2473 // comparisons work.
2474 //
2475 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2476 // code, again so that function address comparisons work.
2477 if (gsym->is_from_dynobj()
2478 || gsym->is_undefined()
2479 || gsym->is_preemptible()
2480 || (gsym->visibility() == elfcpp::STV_PROTECTED
2481 && parameters->options().shared())
2482 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2483 && parameters->options().output_is_position_independent()))
2484 got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
2485 elfcpp::R_X86_64_GLOB_DAT);
2486 else
2487 {
2488 // For a STT_GNU_IFUNC symbol we want to write the PLT
2489 // offset into the GOT, so that function pointer
2490 // comparisons work correctly.
2491 bool is_new;
2492 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2493 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2494 else
2495 {
2496 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2497 // Tell the dynamic linker to use the PLT address
2498 // when resolving relocations.
2499 if (gsym->is_from_dynobj()
2500 && !parameters->options().shared())
2501 gsym->set_needs_dynsym_value();
2502 }
2503 if (is_new)
2504 {
2505 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2506 rela_dyn->add_global_relative(gsym,
2507 elfcpp::R_X86_64_RELATIVE,
2508 got, got_off, 0);
2509 }
2510 }
2511 }
2512 // For GOTPLT64, we also need a PLT entry (but only if the
2513 // symbol is not fully resolved).
2514 if (r_type == elfcpp::R_X86_64_GOTPLT64
2515 && !gsym->final_value_is_known())
2516 target->make_plt_entry(symtab, layout, gsym);
2517 }
2518 break;
2519
2520 case elfcpp::R_X86_64_PLT32:
2521 // If the symbol is fully resolved, this is just a PC32 reloc.
2522 // Otherwise we need a PLT entry.
2523 if (gsym->final_value_is_known())
2524 break;
2525 // If building a shared library, we can also skip the PLT entry
2526 // if the symbol is defined in the output file and is protected
2527 // or hidden.
2528 if (gsym->is_defined()
2529 && !gsym->is_from_dynobj()
2530 && !gsym->is_preemptible())
2531 break;
2532 target->make_plt_entry(symtab, layout, gsym);
2533 break;
2534
2535 case elfcpp::R_X86_64_GOTPC32:
2536 case elfcpp::R_X86_64_GOTOFF64:
2537 case elfcpp::R_X86_64_GOTPC64:
2538 case elfcpp::R_X86_64_PLTOFF64:
2539 // We need a GOT section.
2540 target->got_section(symtab, layout);
2541 // For PLTOFF64, we also need a PLT entry (but only if the
2542 // symbol is not fully resolved).
2543 if (r_type == elfcpp::R_X86_64_PLTOFF64
2544 && !gsym->final_value_is_known())
2545 target->make_plt_entry(symtab, layout, gsym);
2546 break;
2547
2548 case elfcpp::R_X86_64_COPY:
2549 case elfcpp::R_X86_64_GLOB_DAT:
2550 case elfcpp::R_X86_64_JUMP_SLOT:
2551 case elfcpp::R_X86_64_RELATIVE:
2552 case elfcpp::R_X86_64_IRELATIVE:
2553 // These are outstanding tls relocs, which are unexpected when linking
2554 case elfcpp::R_X86_64_TPOFF64:
2555 case elfcpp::R_X86_64_DTPMOD64:
2556 case elfcpp::R_X86_64_TLSDESC:
2557 gold_error(_("%s: unexpected reloc %u in object file"),
2558 object->name().c_str(), r_type);
2559 break;
2560
2561 // These are initial tls relocs, which are expected for global()
2562 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2563 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2564 case elfcpp::R_X86_64_TLSDESC_CALL:
2565 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2566 case elfcpp::R_X86_64_DTPOFF32:
2567 case elfcpp::R_X86_64_DTPOFF64:
2568 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2569 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2570 {
2571 const bool is_final = gsym->final_value_is_known();
2572 const tls::Tls_optimization optimized_type
2573 = Target_x86_64::optimize_tls_reloc(is_final, r_type);
2574 switch (r_type)
2575 {
2576 case elfcpp::R_X86_64_TLSGD: // General-dynamic
2577 if (optimized_type == tls::TLSOPT_NONE)
2578 {
2579 // Create a pair of GOT entries for the module index and
2580 // dtv-relative offset.
2581 Output_data_got<64, false>* got
2582 = target->got_section(symtab, layout);
2583 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
2584 target->rela_dyn_section(layout),
2585 elfcpp::R_X86_64_DTPMOD64,
2586 elfcpp::R_X86_64_DTPOFF64);
2587 }
2588 else if (optimized_type == tls::TLSOPT_TO_IE)
2589 {
2590 // Create a GOT entry for the tp-relative offset.
2591 Output_data_got<64, false>* got
2592 = target->got_section(symtab, layout);
2593 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2594 target->rela_dyn_section(layout),
2595 elfcpp::R_X86_64_TPOFF64);
2596 }
2597 else if (optimized_type != tls::TLSOPT_TO_LE)
2598 unsupported_reloc_global(object, r_type, gsym);
2599 break;
2600
2601 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2602 target->define_tls_base_symbol(symtab, layout);
2603 if (optimized_type == tls::TLSOPT_NONE)
2604 {
2605 // Create reserved PLT and GOT entries for the resolver.
2606 target->reserve_tlsdesc_entries(symtab, layout);
2607
2608 // Create a double GOT entry with an R_X86_64_TLSDESC
2609 // reloc. The R_X86_64_TLSDESC reloc is resolved
2610 // lazily, so the GOT entry needs to be in an area in
2611 // .got.plt, not .got. Call got_section to make sure
2612 // the section has been created.
2613 target->got_section(symtab, layout);
2614 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2615 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2616 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
2617 elfcpp::R_X86_64_TLSDESC, 0);
2618 }
2619 else if (optimized_type == tls::TLSOPT_TO_IE)
2620 {
2621 // Create a GOT entry for the tp-relative offset.
2622 Output_data_got<64, false>* got
2623 = target->got_section(symtab, layout);
2624 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2625 target->rela_dyn_section(layout),
2626 elfcpp::R_X86_64_TPOFF64);
2627 }
2628 else if (optimized_type != tls::TLSOPT_TO_LE)
2629 unsupported_reloc_global(object, r_type, gsym);
2630 break;
2631
2632 case elfcpp::R_X86_64_TLSDESC_CALL:
2633 break;
2634
2635 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2636 if (optimized_type == tls::TLSOPT_NONE)
2637 {
2638 // Create a GOT entry for the module index.
2639 target->got_mod_index_entry(symtab, layout, object);
2640 }
2641 else if (optimized_type != tls::TLSOPT_TO_LE)
2642 unsupported_reloc_global(object, r_type, gsym);
2643 break;
2644
2645 case elfcpp::R_X86_64_DTPOFF32:
2646 case elfcpp::R_X86_64_DTPOFF64:
2647 break;
2648
2649 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2650 layout->set_has_static_tls();
2651 if (optimized_type == tls::TLSOPT_NONE)
2652 {
2653 // Create a GOT entry for the tp-relative offset.
2654 Output_data_got<64, false>* got
2655 = target->got_section(symtab, layout);
2656 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2657 target->rela_dyn_section(layout),
2658 elfcpp::R_X86_64_TPOFF64);
2659 }
2660 else if (optimized_type != tls::TLSOPT_TO_LE)
2661 unsupported_reloc_global(object, r_type, gsym);
2662 break;
2663
2664 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2665 layout->set_has_static_tls();
2666 if (parameters->options().shared())
2667 unsupported_reloc_local(object, r_type);
2668 break;
2669
2670 default:
2671 gold_unreachable();
2672 }
2673 }
2674 break;
2675
2676 case elfcpp::R_X86_64_SIZE32:
2677 case elfcpp::R_X86_64_SIZE64:
2678 default:
2679 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2680 object->name().c_str(), r_type,
2681 gsym->demangled_name().c_str());
2682 break;
2683 }
2684 }
2685
2686 void
2687 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
2688 Layout* layout,
2689 Sized_relobj_file<64, false>* object,
2690 unsigned int data_shndx,
2691 unsigned int sh_type,
2692 const unsigned char* prelocs,
2693 size_t reloc_count,
2694 Output_section* output_section,
2695 bool needs_special_offset_handling,
2696 size_t local_symbol_count,
2697 const unsigned char* plocal_symbols)
2698 {
2699
2700 if (sh_type == elfcpp::SHT_REL)
2701 {
2702 return;
2703 }
2704
2705 gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2706 Target_x86_64::Scan,
2707 Target_x86_64::Relocatable_size_for_reloc>(
2708 symtab,
2709 layout,
2710 this,
2711 object,
2712 data_shndx,
2713 prelocs,
2714 reloc_count,
2715 output_section,
2716 needs_special_offset_handling,
2717 local_symbol_count,
2718 plocal_symbols);
2719
2720 }
2721 // Scan relocations for a section.
2722
2723 void
2724 Target_x86_64::scan_relocs(Symbol_table* symtab,
2725 Layout* layout,
2726 Sized_relobj_file<64, false>* object,
2727 unsigned int data_shndx,
2728 unsigned int sh_type,
2729 const unsigned char* prelocs,
2730 size_t reloc_count,
2731 Output_section* output_section,
2732 bool needs_special_offset_handling,
2733 size_t local_symbol_count,
2734 const unsigned char* plocal_symbols)
2735 {
2736 if (sh_type == elfcpp::SHT_REL)
2737 {
2738 gold_error(_("%s: unsupported REL reloc section"),
2739 object->name().c_str());
2740 return;
2741 }
2742
2743 gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2744 Target_x86_64::Scan>(
2745 symtab,
2746 layout,
2747 this,
2748 object,
2749 data_shndx,
2750 prelocs,
2751 reloc_count,
2752 output_section,
2753 needs_special_offset_handling,
2754 local_symbol_count,
2755 plocal_symbols);
2756 }
2757
2758 // Finalize the sections.
2759
2760 void
2761 Target_x86_64::do_finalize_sections(
2762 Layout* layout,
2763 const Input_objects*,
2764 Symbol_table* symtab)
2765 {
2766 const Reloc_section* rel_plt = (this->plt_ == NULL
2767 ? NULL
2768 : this->plt_->rela_plt());
2769 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
2770 this->rela_dyn_, true, false);
2771
2772 // Fill in some more dynamic tags.
2773 Output_data_dynamic* const odyn = layout->dynamic_data();
2774 if (odyn != NULL)
2775 {
2776 if (this->plt_ != NULL
2777 && this->plt_->output_section() != NULL
2778 && this->plt_->has_tlsdesc_entry())
2779 {
2780 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
2781 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
2782 this->got_->finalize_data_size();
2783 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
2784 this->plt_, plt_offset);
2785 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
2786 this->got_, got_offset);
2787 }
2788 }
2789
2790 // Emit any relocs we saved in an attempt to avoid generating COPY
2791 // relocs.
2792 if (this->copy_relocs_.any_saved_relocs())
2793 this->copy_relocs_.emit(this->rela_dyn_section(layout));
2794
2795 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2796 // the .got.plt section.
2797 Symbol* sym = this->global_offset_table_;
2798 if (sym != NULL)
2799 {
2800 uint64_t data_size = this->got_plt_->current_data_size();
2801 symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
2802 }
2803
2804 if (parameters->doing_static_link()
2805 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2806 {
2807 // If linking statically, make sure that the __rela_iplt symbols
2808 // were defined if necessary, even if we didn't create a PLT.
2809 static const Define_symbol_in_segment syms[] =
2810 {
2811 {
2812 "__rela_iplt_start", // name
2813 elfcpp::PT_LOAD, // segment_type
2814 elfcpp::PF_W, // segment_flags_set
2815 elfcpp::PF(0), // segment_flags_clear
2816 0, // value
2817 0, // size
2818 elfcpp::STT_NOTYPE, // type
2819 elfcpp::STB_GLOBAL, // binding
2820 elfcpp::STV_HIDDEN, // visibility
2821 0, // nonvis
2822 Symbol::SEGMENT_START, // offset_from_base
2823 true // only_if_ref
2824 },
2825 {
2826 "__rela_iplt_end", // name
2827 elfcpp::PT_LOAD, // segment_type
2828 elfcpp::PF_W, // segment_flags_set
2829 elfcpp::PF(0), // segment_flags_clear
2830 0, // value
2831 0, // size
2832 elfcpp::STT_NOTYPE, // type
2833 elfcpp::STB_GLOBAL, // binding
2834 elfcpp::STV_HIDDEN, // visibility
2835 0, // nonvis
2836 Symbol::SEGMENT_START, // offset_from_base
2837 true // only_if_ref
2838 }
2839 };
2840
2841 symtab->define_symbols(layout, 2, syms,
2842 layout->script_options()->saw_sections_clause());
2843 }
2844 }
2845
2846 // Perform a relocation.
2847
2848 inline bool
2849 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
2850 Target_x86_64* target,
2851 Output_section*,
2852 size_t relnum,
2853 const elfcpp::Rela<64, false>& rela,
2854 unsigned int r_type,
2855 const Sized_symbol<64>* gsym,
2856 const Symbol_value<64>* psymval,
2857 unsigned char* view,
2858 elfcpp::Elf_types<64>::Elf_Addr address,
2859 section_size_type view_size)
2860 {
2861 if (this->skip_call_tls_get_addr_)
2862 {
2863 if ((r_type != elfcpp::R_X86_64_PLT32
2864 && r_type != elfcpp::R_X86_64_PC32)
2865 || gsym == NULL
2866 || strcmp(gsym->name(), "__tls_get_addr") != 0)
2867 {
2868 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2869 _("missing expected TLS relocation"));
2870 }
2871 else
2872 {
2873 this->skip_call_tls_get_addr_ = false;
2874 return false;
2875 }
2876 }
2877
2878 const Sized_relobj_file<64, false>* object = relinfo->object;
2879
2880 // Pick the value to use for symbols defined in the PLT.
2881 Symbol_value<64> symval;
2882 if (gsym != NULL
2883 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2884 {
2885 symval.set_output_value(target->plt_address_for_global(gsym)
2886 + gsym->plt_offset());
2887 psymval = &symval;
2888 }
2889 else if (gsym == NULL && psymval->is_ifunc_symbol())
2890 {
2891 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2892 if (object->local_has_plt_offset(r_sym))
2893 {
2894 symval.set_output_value(target->plt_address_for_local(object, r_sym)
2895 + object->local_plt_offset(r_sym));
2896 psymval = &symval;
2897 }
2898 }
2899
2900 const elfcpp::Elf_Xword addend = rela.get_r_addend();
2901
2902 // Get the GOT offset if needed.
2903 // The GOT pointer points to the end of the GOT section.
2904 // We need to subtract the size of the GOT section to get
2905 // the actual offset to use in the relocation.
2906 bool have_got_offset = false;
2907 unsigned int got_offset = 0;
2908 switch (r_type)
2909 {
2910 case elfcpp::R_X86_64_GOT32:
2911 case elfcpp::R_X86_64_GOT64:
2912 case elfcpp::R_X86_64_GOTPLT64:
2913 case elfcpp::R_X86_64_GOTPCREL:
2914 case elfcpp::R_X86_64_GOTPCREL64:
2915 if (gsym != NULL)
2916 {
2917 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2918 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
2919 }
2920 else
2921 {
2922 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2923 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2924 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2925 - target->got_size());
2926 }
2927 have_got_offset = true;
2928 break;
2929
2930 default:
2931 break;
2932 }
2933
2934 switch (r_type)
2935 {
2936 case elfcpp::R_X86_64_NONE:
2937 case elfcpp::R_X86_64_GNU_VTINHERIT:
2938 case elfcpp::R_X86_64_GNU_VTENTRY:
2939 break;
2940
2941 case elfcpp::R_X86_64_64:
2942 Relocate_functions<64, false>::rela64(view, object, psymval, addend);
2943 break;
2944
2945 case elfcpp::R_X86_64_PC64:
2946 Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
2947 address);
2948 break;
2949
2950 case elfcpp::R_X86_64_32:
2951 // FIXME: we need to verify that value + addend fits into 32 bits:
2952 // uint64_t x = value + addend;
2953 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2954 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2955 Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2956 break;
2957
2958 case elfcpp::R_X86_64_32S:
2959 // FIXME: we need to verify that value + addend fits into 32 bits:
2960 // int64_t x = value + addend; // note this quantity is signed!
2961 // x == static_cast<int64_t>(static_cast<int32_t>(x))
2962 Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2963 break;
2964
2965 case elfcpp::R_X86_64_PC32:
2966 Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2967 address);
2968 break;
2969
2970 case elfcpp::R_X86_64_16:
2971 Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2972 break;
2973
2974 case elfcpp::R_X86_64_PC16:
2975 Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2976 address);
2977 break;
2978
2979 case elfcpp::R_X86_64_8:
2980 Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2981 break;
2982
2983 case elfcpp::R_X86_64_PC8:
2984 Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2985 address);
2986 break;
2987
2988 case elfcpp::R_X86_64_PLT32:
2989 gold_assert(gsym == NULL
2990 || gsym->has_plt_offset()
2991 || gsym->final_value_is_known()
2992 || (gsym->is_defined()
2993 && !gsym->is_from_dynobj()
2994 && !gsym->is_preemptible()));
2995 // Note: while this code looks the same as for R_X86_64_PC32, it
2996 // behaves differently because psymval was set to point to
2997 // the PLT entry, rather than the symbol, in Scan::global().
2998 Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2999 address);
3000 break;
3001
3002 case elfcpp::R_X86_64_PLTOFF64:
3003 {
3004 gold_assert(gsym);
3005 gold_assert(gsym->has_plt_offset()
3006 || gsym->final_value_is_known());
3007 elfcpp::Elf_types<64>::Elf_Addr got_address;
3008 got_address = target->got_section(NULL, NULL)->address();
3009 Relocate_functions<64, false>::rela64(view, object, psymval,
3010 addend - got_address);
3011 }
3012
3013 case elfcpp::R_X86_64_GOT32:
3014 gold_assert(have_got_offset);
3015 Relocate_functions<64, false>::rela32(view, got_offset, addend);
3016 break;
3017
3018 case elfcpp::R_X86_64_GOTPC32:
3019 {
3020 gold_assert(gsym);
3021 elfcpp::Elf_types<64>::Elf_Addr value;
3022 value = target->got_plt_section()->address();
3023 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
3024 }
3025 break;
3026
3027 case elfcpp::R_X86_64_GOT64:
3028 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
3029 // Since we always add a PLT entry, this is equivalent.
3030 case elfcpp::R_X86_64_GOTPLT64:
3031 gold_assert(have_got_offset);
3032 Relocate_functions<64, false>::rela64(view, got_offset, addend);
3033 break;
3034
3035 case elfcpp::R_X86_64_GOTPC64:
3036 {
3037 gold_assert(gsym);
3038 elfcpp::Elf_types<64>::Elf_Addr value;
3039 value = target->got_plt_section()->address();
3040 Relocate_functions<64, false>::pcrela64(view, value, addend, address);
3041 }
3042 break;
3043
3044 case elfcpp::R_X86_64_GOTOFF64:
3045 {
3046 elfcpp::Elf_types<64>::Elf_Addr value;
3047 value = (psymval->value(object, 0)
3048 - target->got_plt_section()->address());
3049 Relocate_functions<64, false>::rela64(view, value, addend);
3050 }
3051 break;
3052
3053 case elfcpp::R_X86_64_GOTPCREL:
3054 {
3055 gold_assert(have_got_offset);
3056 elfcpp::Elf_types<64>::Elf_Addr value;
3057 value = target->got_plt_section()->address() + got_offset;
3058 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
3059 }
3060 break;
3061
3062 case elfcpp::R_X86_64_GOTPCREL64:
3063 {
3064 gold_assert(have_got_offset);
3065 elfcpp::Elf_types<64>::Elf_Addr value;
3066 value = target->got_plt_section()->address() + got_offset;
3067 Relocate_functions<64, false>::pcrela64(view, value, addend, address);
3068 }
3069 break;
3070
3071 case elfcpp::R_X86_64_COPY:
3072 case elfcpp::R_X86_64_GLOB_DAT:
3073 case elfcpp::R_X86_64_JUMP_SLOT:
3074 case elfcpp::R_X86_64_RELATIVE:
3075 case elfcpp::R_X86_64_IRELATIVE:
3076 // These are outstanding tls relocs, which are unexpected when linking
3077 case elfcpp::R_X86_64_TPOFF64:
3078 case elfcpp::R_X86_64_DTPMOD64:
3079 case elfcpp::R_X86_64_TLSDESC:
3080 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3081 _("unexpected reloc %u in object file"),
3082 r_type);
3083 break;
3084
3085 // These are initial tls relocs, which are expected when linking
3086 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3087 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3088 case elfcpp::R_X86_64_TLSDESC_CALL:
3089 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3090 case elfcpp::R_X86_64_DTPOFF32:
3091 case elfcpp::R_X86_64_DTPOFF64:
3092 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3093 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3094 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
3095 view, address, view_size);
3096 break;
3097
3098 case elfcpp::R_X86_64_SIZE32:
3099 case elfcpp::R_X86_64_SIZE64:
3100 default:
3101 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3102 _("unsupported reloc %u"),
3103 r_type);
3104 break;
3105 }
3106
3107 return true;
3108 }
3109
3110 // Perform a TLS relocation.
3111
3112 inline void
3113 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
3114 Target_x86_64* target,
3115 size_t relnum,
3116 const elfcpp::Rela<64, false>& rela,
3117 unsigned int r_type,
3118 const Sized_symbol<64>* gsym,
3119 const Symbol_value<64>* psymval,
3120 unsigned char* view,
3121 elfcpp::Elf_types<64>::Elf_Addr address,
3122 section_size_type view_size)
3123 {
3124 Output_segment* tls_segment = relinfo->layout->tls_segment();
3125
3126 const Sized_relobj_file<64, false>* object = relinfo->object;
3127 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3128 elfcpp::Shdr<64, false> data_shdr(relinfo->data_shdr);
3129 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
3130
3131 elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
3132
3133 const bool is_final = (gsym == NULL
3134 ? !parameters->options().shared()
3135 : gsym->final_value_is_known());
3136 tls::Tls_optimization optimized_type
3137 = Target_x86_64::optimize_tls_reloc(is_final, r_type);
3138 switch (r_type)
3139 {
3140 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3141 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3142 {
3143 // If this code sequence is used in a non-executable section,
3144 // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
3145 // on the assumption that it's being used by itself in a debug
3146 // section. Therefore, in the unlikely event that the code
3147 // sequence appears in a non-executable section, we simply
3148 // leave it unoptimized.
3149 optimized_type = tls::TLSOPT_NONE;
3150 }
3151 if (optimized_type == tls::TLSOPT_TO_LE)
3152 {
3153 if (tls_segment == NULL)
3154 {
3155 gold_assert(parameters->errors()->error_count() > 0
3156 || issue_undefined_symbol_error(gsym));
3157 return;
3158 }
3159 this->tls_gd_to_le(relinfo, relnum, tls_segment,
3160 rela, r_type, value, view,
3161 view_size);
3162 break;
3163 }
3164 else
3165 {
3166 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3167 ? GOT_TYPE_TLS_OFFSET
3168 : GOT_TYPE_TLS_PAIR);
3169 unsigned int got_offset;
3170 if (gsym != NULL)
3171 {
3172 gold_assert(gsym->has_got_offset(got_type));
3173 got_offset = gsym->got_offset(got_type) - target->got_size();
3174 }
3175 else
3176 {
3177 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
3178 gold_assert(object->local_has_got_offset(r_sym, got_type));
3179 got_offset = (object->local_got_offset(r_sym, got_type)
3180 - target->got_size());
3181 }
3182 if (optimized_type == tls::TLSOPT_TO_IE)
3183 {
3184 value = target->got_plt_section()->address() + got_offset;
3185 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
3186 value, view, address, view_size);
3187 break;
3188 }
3189 else if (optimized_type == tls::TLSOPT_NONE)
3190 {
3191 // Relocate the field with the offset of the pair of GOT
3192 // entries.
3193 value = target->got_plt_section()->address() + got_offset;
3194 Relocate_functions<64, false>::pcrela32(view, value, addend,
3195 address);
3196 break;
3197 }
3198 }
3199 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3200 _("unsupported reloc %u"), r_type);
3201 break;
3202
3203 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3204 case elfcpp::R_X86_64_TLSDESC_CALL:
3205 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3206 {
3207 // See above comment for R_X86_64_TLSGD.
3208 optimized_type = tls::TLSOPT_NONE;
3209 }
3210 if (optimized_type == tls::TLSOPT_TO_LE)
3211 {
3212 if (tls_segment == NULL)
3213 {
3214 gold_assert(parameters->errors()->error_count() > 0
3215 || issue_undefined_symbol_error(gsym));
3216 return;
3217 }
3218 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3219 rela, r_type, value, view,
3220 view_size);
3221 break;
3222 }
3223 else
3224 {
3225 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3226 ? GOT_TYPE_TLS_OFFSET
3227 : GOT_TYPE_TLS_DESC);
3228 unsigned int got_offset = 0;
3229 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
3230 && optimized_type == tls::TLSOPT_NONE)
3231 {
3232 // We created GOT entries in the .got.tlsdesc portion of
3233 // the .got.plt section, but the offset stored in the
3234 // symbol is the offset within .got.tlsdesc.
3235 got_offset = (target->got_size()
3236 + target->got_plt_section()->data_size());
3237 }
3238 if (gsym != NULL)
3239 {
3240 gold_assert(gsym->has_got_offset(got_type));
3241 got_offset += gsym->got_offset(got_type) - target->got_size();
3242 }
3243 else
3244 {
3245 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
3246 gold_assert(object->local_has_got_offset(r_sym, got_type));
3247 got_offset += (object->local_got_offset(r_sym, got_type)
3248 - target->got_size());
3249 }
3250 if (optimized_type == tls::TLSOPT_TO_IE)
3251 {
3252 if (tls_segment == NULL)
3253 {
3254 gold_assert(parameters->errors()->error_count() > 0
3255 || issue_undefined_symbol_error(gsym));
3256 return;
3257 }
3258 value = target->got_plt_section()->address() + got_offset;
3259 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
3260 rela, r_type, value, view, address,
3261 view_size);
3262 break;
3263 }
3264 else if (optimized_type == tls::TLSOPT_NONE)
3265 {
3266 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3267 {
3268 // Relocate the field with the offset of the pair of GOT
3269 // entries.
3270 value = target->got_plt_section()->address() + got_offset;
3271 Relocate_functions<64, false>::pcrela32(view, value, addend,
3272 address);
3273 }
3274 break;
3275 }
3276 }
3277 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3278 _("unsupported reloc %u"), r_type);
3279 break;
3280
3281 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3282 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3283 {
3284 // See above comment for R_X86_64_TLSGD.
3285 optimized_type = tls::TLSOPT_NONE;
3286 }
3287 if (optimized_type == tls::TLSOPT_TO_LE)
3288 {
3289 if (tls_segment == NULL)
3290 {
3291 gold_assert(parameters->errors()->error_count() > 0
3292 || issue_undefined_symbol_error(gsym));
3293 return;
3294 }
3295 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
3296 value, view, view_size);
3297 break;
3298 }
3299 else if (optimized_type == tls::TLSOPT_NONE)
3300 {
3301 // Relocate the field with the offset of the GOT entry for
3302 // the module index.
3303 unsigned int got_offset;
3304 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3305 - target->got_size());
3306 value = target->got_plt_section()->address() + got_offset;
3307 Relocate_functions<64, false>::pcrela32(view, value, addend,
3308 address);
3309 break;
3310 }
3311 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3312 _("unsupported reloc %u"), r_type);
3313 break;
3314
3315 case elfcpp::R_X86_64_DTPOFF32:
3316 // This relocation type is used in debugging information.
3317 // In that case we need to not optimize the value. If the
3318 // section is not executable, then we assume we should not
3319 // optimize this reloc. See comments above for R_X86_64_TLSGD,
3320 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
3321 // R_X86_64_TLSLD.
3322 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3323 {
3324 if (tls_segment == NULL)
3325 {
3326 gold_assert(parameters->errors()->error_count() > 0
3327 || issue_undefined_symbol_error(gsym));
3328 return;
3329 }
3330 value -= tls_segment->memsz();
3331 }
3332 Relocate_functions<64, false>::rela32(view, value, addend);
3333 break;
3334
3335 case elfcpp::R_X86_64_DTPOFF64:
3336 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
3337 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3338 {
3339 if (tls_segment == NULL)
3340 {
3341 gold_assert(parameters->errors()->error_count() > 0
3342 || issue_undefined_symbol_error(gsym));
3343 return;
3344 }
3345 value -= tls_segment->memsz();
3346 }
3347 Relocate_functions<64, false>::rela64(view, value, addend);
3348 break;
3349
3350 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3351 if (optimized_type == tls::TLSOPT_TO_LE)
3352 {
3353 if (tls_segment == NULL)
3354 {
3355 gold_assert(parameters->errors()->error_count() > 0
3356 || issue_undefined_symbol_error(gsym));
3357 return;
3358 }
3359 Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3360 rela, r_type, value, view,
3361 view_size);
3362 break;
3363 }
3364 else if (optimized_type == tls::TLSOPT_NONE)
3365 {
3366 // Relocate the field with the offset of the GOT entry for
3367 // the tp-relative offset of the symbol.
3368 unsigned int got_offset;
3369 if (gsym != NULL)
3370 {
3371 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
3372 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
3373 - target->got_size());
3374 }
3375 else
3376 {
3377 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
3378 gold_assert(object->local_has_got_offset(r_sym,
3379 GOT_TYPE_TLS_OFFSET));
3380 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
3381 - target->got_size());
3382 }
3383 value = target->got_plt_section()->address() + got_offset;
3384 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
3385 break;
3386 }
3387 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3388 _("unsupported reloc type %u"),
3389 r_type);
3390 break;
3391
3392 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3393 if (tls_segment == NULL)
3394 {
3395 gold_assert(parameters->errors()->error_count() > 0
3396 || issue_undefined_symbol_error(gsym));
3397 return;
3398 }
3399 value -= tls_segment->memsz();
3400 Relocate_functions<64, false>::rela32(view, value, addend);
3401 break;
3402 }
3403 }
3404
3405 // Do a relocation in which we convert a TLS General-Dynamic to an
3406 // Initial-Exec.
3407
3408 inline void
3409 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
3410 size_t relnum,
3411 Output_segment*,
3412 const elfcpp::Rela<64, false>& rela,
3413 unsigned int,
3414 elfcpp::Elf_types<64>::Elf_Addr value,
3415 unsigned char* view,
3416 elfcpp::Elf_types<64>::Elf_Addr address,
3417 section_size_type view_size)
3418 {
3419 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3420 // .word 0x6666; rex64; call __tls_get_addr
3421 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
3422
3423 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
3424 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3425
3426 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3427 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3428 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3429 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3430
3431 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
3432
3433 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3434 Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
3435
3436 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3437 // We can skip it.
3438 this->skip_call_tls_get_addr_ = true;
3439 }
3440
3441 // Do a relocation in which we convert a TLS General-Dynamic to a
3442 // Local-Exec.
3443
3444 inline void
3445 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
3446 size_t relnum,
3447 Output_segment* tls_segment,
3448 const elfcpp::Rela<64, false>& rela,
3449 unsigned int,
3450 elfcpp::Elf_types<64>::Elf_Addr value,
3451 unsigned char* view,
3452 section_size_type view_size)
3453 {
3454 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3455 // .word 0x6666; rex64; call __tls_get_addr
3456 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
3457
3458 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
3459 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3460
3461 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3462 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3463 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3464 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3465
3466 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
3467
3468 value -= tls_segment->memsz();
3469 Relocate_functions<64, false>::rela32(view + 8, value, 0);
3470
3471 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3472 // We can skip it.
3473 this->skip_call_tls_get_addr_ = true;
3474 }
3475
3476 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
3477
3478 inline void
3479 Target_x86_64::Relocate::tls_desc_gd_to_ie(
3480 const Relocate_info<64, false>* relinfo,
3481 size_t relnum,
3482 Output_segment*,
3483 const elfcpp::Rela<64, false>& rela,
3484 unsigned int r_type,
3485 elfcpp::Elf_types<64>::Elf_Addr value,
3486 unsigned char* view,
3487 elfcpp::Elf_types<64>::Elf_Addr address,
3488 section_size_type view_size)
3489 {
3490 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3491 {
3492 // leaq foo@tlsdesc(%rip), %rax
3493 // ==> movq foo@gottpoff(%rip), %rax
3494 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3495 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3496 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3497 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3498 view[-2] = 0x8b;
3499 const elfcpp::Elf_Xword addend = rela.get_r_addend();
3500 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
3501 }
3502 else
3503 {
3504 // call *foo@tlscall(%rax)
3505 // ==> nop; nop
3506 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3507 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3508 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3509 view[0] == 0xff && view[1] == 0x10);
3510 view[0] = 0x66;
3511 view[1] = 0x90;
3512 }
3513 }
3514
3515 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
3516
3517 inline void
3518 Target_x86_64::Relocate::tls_desc_gd_to_le(
3519 const Relocate_info<64, false>* relinfo,
3520 size_t relnum,
3521 Output_segment* tls_segment,
3522 const elfcpp::Rela<64, false>& rela,
3523 unsigned int r_type,
3524 elfcpp::Elf_types<64>::Elf_Addr value,
3525 unsigned char* view,
3526 section_size_type view_size)
3527 {
3528 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3529 {
3530 // leaq foo@tlsdesc(%rip), %rax
3531 // ==> movq foo@tpoff, %rax
3532 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3533 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3534 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3535 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3536 view[-2] = 0xc7;
3537 view[-1] = 0xc0;
3538 value -= tls_segment->memsz();
3539 Relocate_functions<64, false>::rela32(view, value, 0);
3540 }
3541 else
3542 {
3543 // call *foo@tlscall(%rax)
3544 // ==> nop; nop
3545 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3546 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3547 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3548 view[0] == 0xff && view[1] == 0x10);
3549 view[0] = 0x66;
3550 view[1] = 0x90;
3551 }
3552 }
3553
3554 inline void
3555 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
3556 size_t relnum,
3557 Output_segment*,
3558 const elfcpp::Rela<64, false>& rela,
3559 unsigned int,
3560 elfcpp::Elf_types<64>::Elf_Addr,
3561 unsigned char* view,
3562 section_size_type view_size)
3563 {
3564 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
3565 // ... leq foo@dtpoff(%rax),%reg
3566 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
3567
3568 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3569 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
3570
3571 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3572 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
3573
3574 tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
3575
3576 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
3577
3578 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3579 // We can skip it.
3580 this->skip_call_tls_get_addr_ = true;
3581 }
3582
3583 // Do a relocation in which we convert a TLS Initial-Exec to a
3584 // Local-Exec.
3585
3586 inline void
3587 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
3588 size_t relnum,
3589 Output_segment* tls_segment,
3590 const elfcpp::Rela<64, false>& rela,
3591 unsigned int,
3592 elfcpp::Elf_types<64>::Elf_Addr value,
3593 unsigned char* view,
3594 section_size_type view_size)
3595 {
3596 // We need to examine the opcodes to figure out which instruction we
3597 // are looking at.
3598
3599 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
3600 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
3601
3602 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3603 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3604
3605 unsigned char op1 = view[-3];
3606 unsigned char op2 = view[-2];
3607 unsigned char op3 = view[-1];
3608 unsigned char reg = op3 >> 3;
3609
3610 if (op2 == 0x8b)
3611 {
3612 // movq
3613 if (op1 == 0x4c)
3614 view[-3] = 0x49;
3615 view[-2] = 0xc7;
3616 view[-1] = 0xc0 | reg;
3617 }
3618 else if (reg == 4)
3619 {
3620 // Special handling for %rsp.
3621 if (op1 == 0x4c)
3622 view[-3] = 0x49;
3623 view[-2] = 0x81;
3624 view[-1] = 0xc0 | reg;
3625 }
3626 else
3627 {
3628 // addq
3629 if (op1 == 0x4c)
3630 view[-3] = 0x4d;
3631 view[-2] = 0x8d;
3632 view[-1] = 0x80 | reg | (reg << 3);
3633 }
3634
3635 value -= tls_segment->memsz();
3636 Relocate_functions<64, false>::rela32(view, value, 0);
3637 }
3638
3639 // Relocate section data.
3640
3641 void
3642 Target_x86_64::relocate_section(
3643 const Relocate_info<64, false>* relinfo,
3644 unsigned int sh_type,
3645 const unsigned char* prelocs,
3646 size_t reloc_count,
3647 Output_section* output_section,
3648 bool needs_special_offset_handling,
3649 unsigned char* view,
3650 elfcpp::Elf_types<64>::Elf_Addr address,
3651 section_size_type view_size,
3652 const Reloc_symbol_changes* reloc_symbol_changes)
3653 {
3654 gold_assert(sh_type == elfcpp::SHT_RELA);
3655
3656 gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
3657 Target_x86_64::Relocate>(
3658 relinfo,
3659 this,
3660 prelocs,
3661 reloc_count,
3662 output_section,
3663 needs_special_offset_handling,
3664 view,
3665 address,
3666 view_size,
3667 reloc_symbol_changes);
3668 }
3669
3670 // Apply an incremental relocation. Incremental relocations always refer
3671 // to global symbols.
3672
3673 void
3674 Target_x86_64::apply_relocation(
3675 const Relocate_info<64, false>* relinfo,
3676 elfcpp::Elf_types<64>::Elf_Addr r_offset,
3677 unsigned int r_type,
3678 elfcpp::Elf_types<64>::Elf_Swxword r_addend,
3679 const Symbol* gsym,
3680 unsigned char* view,
3681 elfcpp::Elf_types<64>::Elf_Addr address,
3682 section_size_type view_size)
3683 {
3684 gold::apply_relocation<64, false, Target_x86_64, Target_x86_64::Relocate>(
3685 relinfo,
3686 this,
3687 r_offset,
3688 r_type,
3689 r_addend,
3690 gsym,
3691 view,
3692 address,
3693 view_size);
3694 }
3695
3696 // Return the size of a relocation while scanning during a relocatable
3697 // link.
3698
3699 unsigned int
3700 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
3701 unsigned int r_type,
3702 Relobj* object)
3703 {
3704 switch (r_type)
3705 {
3706 case elfcpp::R_X86_64_NONE:
3707 case elfcpp::R_X86_64_GNU_VTINHERIT:
3708 case elfcpp::R_X86_64_GNU_VTENTRY:
3709 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3710 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3711 case elfcpp::R_X86_64_TLSDESC_CALL:
3712 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3713 case elfcpp::R_X86_64_DTPOFF32:
3714 case elfcpp::R_X86_64_DTPOFF64:
3715 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3716 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3717 return 0;
3718
3719 case elfcpp::R_X86_64_64:
3720 case elfcpp::R_X86_64_PC64:
3721 case elfcpp::R_X86_64_GOTOFF64:
3722 case elfcpp::R_X86_64_GOTPC64:
3723 case elfcpp::R_X86_64_PLTOFF64:
3724 case elfcpp::R_X86_64_GOT64:
3725 case elfcpp::R_X86_64_GOTPCREL64:
3726 case elfcpp::R_X86_64_GOTPCREL:
3727 case elfcpp::R_X86_64_GOTPLT64:
3728 return 8;
3729
3730 case elfcpp::R_X86_64_32:
3731 case elfcpp::R_X86_64_32S:
3732 case elfcpp::R_X86_64_PC32:
3733 case elfcpp::R_X86_64_PLT32:
3734 case elfcpp::R_X86_64_GOTPC32:
3735 case elfcpp::R_X86_64_GOT32:
3736 return 4;
3737
3738 case elfcpp::R_X86_64_16:
3739 case elfcpp::R_X86_64_PC16:
3740 return 2;
3741
3742 case elfcpp::R_X86_64_8:
3743 case elfcpp::R_X86_64_PC8:
3744 return 1;
3745
3746 case elfcpp::R_X86_64_COPY:
3747 case elfcpp::R_X86_64_GLOB_DAT:
3748 case elfcpp::R_X86_64_JUMP_SLOT:
3749 case elfcpp::R_X86_64_RELATIVE:
3750 case elfcpp::R_X86_64_IRELATIVE:
3751 // These are outstanding tls relocs, which are unexpected when linking
3752 case elfcpp::R_X86_64_TPOFF64:
3753 case elfcpp::R_X86_64_DTPMOD64:
3754 case elfcpp::R_X86_64_TLSDESC:
3755 object->error(_("unexpected reloc %u in object file"), r_type);
3756 return 0;
3757
3758 case elfcpp::R_X86_64_SIZE32:
3759 case elfcpp::R_X86_64_SIZE64:
3760 default:
3761 object->error(_("unsupported reloc %u against local symbol"), r_type);
3762 return 0;
3763 }
3764 }
3765
3766 // Scan the relocs during a relocatable link.
3767
3768 void
3769 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
3770 Layout* layout,
3771 Sized_relobj_file<64, false>* object,
3772 unsigned int data_shndx,
3773 unsigned int sh_type,
3774 const unsigned char* prelocs,
3775 size_t reloc_count,
3776 Output_section* output_section,
3777 bool needs_special_offset_handling,
3778 size_t local_symbol_count,
3779 const unsigned char* plocal_symbols,
3780 Relocatable_relocs* rr)
3781 {
3782 gold_assert(sh_type == elfcpp::SHT_RELA);
3783
3784 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
3785 Relocatable_size_for_reloc> Scan_relocatable_relocs;
3786
3787 gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
3788 Scan_relocatable_relocs>(
3789 symtab,
3790 layout,
3791 object,
3792 data_shndx,
3793 prelocs,
3794 reloc_count,
3795 output_section,
3796 needs_special_offset_handling,
3797 local_symbol_count,
3798 plocal_symbols,
3799 rr);
3800 }
3801
3802 // Relocate a section during a relocatable link.
3803
3804 void
3805 Target_x86_64::relocate_for_relocatable(
3806 const Relocate_info<64, false>* relinfo,
3807 unsigned int sh_type,
3808 const unsigned char* prelocs,
3809 size_t reloc_count,
3810 Output_section* output_section,
3811 off_t offset_in_output_section,
3812 const Relocatable_relocs* rr,
3813 unsigned char* view,
3814 elfcpp::Elf_types<64>::Elf_Addr view_address,
3815 section_size_type view_size,
3816 unsigned char* reloc_view,
3817 section_size_type reloc_view_size)
3818 {
3819 gold_assert(sh_type == elfcpp::SHT_RELA);
3820
3821 gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
3822 relinfo,
3823 prelocs,
3824 reloc_count,
3825 output_section,
3826 offset_in_output_section,
3827 rr,
3828 view,
3829 view_address,
3830 view_size,
3831 reloc_view,
3832 reloc_view_size);
3833 }
3834
3835 // Return the value to use for a dynamic which requires special
3836 // treatment. This is how we support equality comparisons of function
3837 // pointers across shared library boundaries, as described in the
3838 // processor specific ABI supplement.
3839
3840 uint64_t
3841 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
3842 {
3843 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3844 return this->plt_address_for_global(gsym) + gsym->plt_offset();
3845 }
3846
3847 // Return a string used to fill a code section with nops to take up
3848 // the specified length.
3849
3850 std::string
3851 Target_x86_64::do_code_fill(section_size_type length) const
3852 {
3853 if (length >= 16)
3854 {
3855 // Build a jmpq instruction to skip over the bytes.
3856 unsigned char jmp[5];
3857 jmp[0] = 0xe9;
3858 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3859 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3860 + std::string(length - 5, '\0'));
3861 }
3862
3863 // Nop sequences of various lengths.
3864 const char nop1[1] = { 0x90 }; // nop
3865 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
3866 const char nop3[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax)
3867 const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax)
3868 const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1)
3869 0x00 };
3870 const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1)
3871 0x00, 0x00 };
3872 const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax)
3873 0x00, 0x00, 0x00 };
3874 const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1)
3875 0x00, 0x00, 0x00, 0x00 };
3876 const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1)
3877 0x00, 0x00, 0x00, 0x00,
3878 0x00 };
3879 const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
3880 0x84, 0x00, 0x00, 0x00,
3881 0x00, 0x00 };
3882 const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
3883 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3884 0x00, 0x00, 0x00 };
3885 const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
3886 0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
3887 0x00, 0x00, 0x00, 0x00 };
3888 const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3889 0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
3890 0x00, 0x00, 0x00, 0x00,
3891 0x00 };
3892 const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3893 0x66, 0x2e, 0x0f, 0x1f, // data16
3894 0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3895 0x00, 0x00 };
3896 const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3897 0x66, 0x66, 0x2e, 0x0f, // data16; data16
3898 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3899 0x00, 0x00, 0x00 };
3900
3901 const char* nops[16] = {
3902 NULL,
3903 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3904 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3905 };
3906
3907 return std::string(nops[length], length);
3908 }
3909
3910 // Return the addend to use for a target specific relocation. The
3911 // only target specific relocation is R_X86_64_TLSDESC for a local
3912 // symbol. We want to set the addend is the offset of the local
3913 // symbol in the TLS segment.
3914
3915 uint64_t
3916 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
3917 uint64_t) const
3918 {
3919 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
3920 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
3921 gold_assert(intarg < this->tlsdesc_reloc_info_.size());
3922 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
3923 const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
3924 gold_assert(psymval->is_tls_symbol());
3925 // The value of a TLS symbol is the offset in the TLS segment.
3926 return psymval->value(ti.object, 0);
3927 }
3928
3929 // Return the value to use for the base of a DW_EH_PE_datarel offset
3930 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3931 // assembler can not write out the difference between two labels in
3932 // different sections, so instead of using a pc-relative value they
3933 // use an offset from the GOT.
3934
3935 uint64_t
3936 Target_x86_64::do_ehframe_datarel_base() const
3937 {
3938 gold_assert(this->global_offset_table_ != NULL);
3939 Symbol* sym = this->global_offset_table_;
3940 Sized_symbol<64>* ssym = static_cast<Sized_symbol<64>*>(sym);
3941 return ssym->value();
3942 }
3943
3944 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3945 // compiled with -fsplit-stack. The function calls non-split-stack
3946 // code. We have to change the function so that it always ensures
3947 // that it has enough stack space to run some random function.
3948
3949 void
3950 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
3951 section_offset_type fnoffset,
3952 section_size_type fnsize,
3953 unsigned char* view,
3954 section_size_type view_size,
3955 std::string* from,
3956 std::string* to) const
3957 {
3958 // The function starts with a comparison of the stack pointer and a
3959 // field in the TCB. This is followed by a jump.
3960
3961 // cmp %fs:NN,%rsp
3962 if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
3963 && fnsize > 9)
3964 {
3965 // We will call __morestack if the carry flag is set after this
3966 // comparison. We turn the comparison into an stc instruction
3967 // and some nops.
3968 view[fnoffset] = '\xf9';
3969 this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
3970 }
3971 // lea NN(%rsp),%r10
3972 // lea NN(%rsp),%r11
3973 else if ((this->match_view(view, view_size, fnoffset,
3974 "\x4c\x8d\x94\x24", 4)
3975 || this->match_view(view, view_size, fnoffset,
3976 "\x4c\x8d\x9c\x24", 4))
3977 && fnsize > 8)
3978 {
3979 // This is loading an offset from the stack pointer for a
3980 // comparison. The offset is negative, so we decrease the
3981 // offset by the amount of space we need for the stack. This
3982 // means we will avoid calling __morestack if there happens to
3983 // be plenty of space on the stack already.
3984 unsigned char* pval = view + fnoffset + 4;
3985 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3986 val -= parameters->options().split_stack_adjust_size();
3987 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3988 }
3989 else
3990 {
3991 if (!object->has_no_split_stack())
3992 object->error(_("failed to match split-stack sequence at "
3993 "section %u offset %0zx"),
3994 shndx, static_cast<size_t>(fnoffset));
3995 return;
3996 }
3997
3998 // We have to change the function so that it calls
3999 // __morestack_non_split instead of __morestack. The former will
4000 // allocate additional stack space.
4001 *from = "__morestack";
4002 *to = "__morestack_non_split";
4003 }
4004
4005 // The selector for x86_64 object files.
4006
4007 class Target_selector_x86_64 : public Target_selector_freebsd
4008 {
4009 public:
4010 Target_selector_x86_64()
4011 : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
4012 "elf64-x86-64-freebsd", "elf_x86_64")
4013 { }
4014
4015 Target*
4016 do_instantiate_target()
4017 { return new Target_x86_64(); }
4018
4019 };
4020
4021 Target_selector_x86_64 target_selector_x86_64;
4022
4023 } // End anonymous namespace.
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