gdb: add target_ops::supports_displaced_step
[deliverable/binutils-gdb.git] / gold / x86_64.cc
1 // x86_64.cc -- x86_64 target support for gold.
2
3 // Copyright (C) 2006-2020 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 "nacl.h"
43 #include "gc.h"
44 #include "icf.h"
45
46 namespace
47 {
48
49 using namespace gold;
50
51 // A class to handle the .got.plt section.
52
53 class Output_data_got_plt_x86_64 : public Output_section_data_build
54 {
55 public:
56 Output_data_got_plt_x86_64(Layout* layout)
57 : Output_section_data_build(8),
58 layout_(layout)
59 { }
60
61 Output_data_got_plt_x86_64(Layout* layout, off_t data_size)
62 : Output_section_data_build(data_size, 8),
63 layout_(layout)
64 { }
65
66 protected:
67 // Write out the PLT data.
68 void
69 do_write(Output_file*);
70
71 // Write to a map file.
72 void
73 do_print_to_mapfile(Mapfile* mapfile) const
74 { mapfile->print_output_data(this, "** GOT PLT"); }
75
76 private:
77 // A pointer to the Layout class, so that we can find the .dynamic
78 // section when we write out the GOT PLT section.
79 Layout* layout_;
80 };
81
82 // A class to handle the PLT data.
83 // This is an abstract base class that handles most of the linker details
84 // but does not know the actual contents of PLT entries. The derived
85 // classes below fill in those details.
86
87 template<int size>
88 class Output_data_plt_x86_64 : public Output_section_data
89 {
90 public:
91 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
92
93 Output_data_plt_x86_64(Layout* layout, uint64_t addralign,
94 Output_data_got<64, false>* got,
95 Output_data_got_plt_x86_64* got_plt,
96 Output_data_space* got_irelative)
97 : Output_section_data(addralign), tlsdesc_rel_(NULL),
98 irelative_rel_(NULL), got_(got), got_plt_(got_plt),
99 got_irelative_(got_irelative), count_(0), irelative_count_(0),
100 tlsdesc_got_offset_(-1U), free_list_()
101 { this->init(layout); }
102
103 Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size,
104 Output_data_got<64, false>* got,
105 Output_data_got_plt_x86_64* got_plt,
106 Output_data_space* got_irelative,
107 unsigned int plt_count)
108 : Output_section_data((plt_count + 1) * plt_entry_size,
109 plt_entry_size, false),
110 tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
111 got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
112 irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
113 {
114 this->init(layout);
115
116 // Initialize the free list and reserve the first entry.
117 this->free_list_.init((plt_count + 1) * plt_entry_size, false);
118 this->free_list_.remove(0, plt_entry_size);
119 }
120
121 // Initialize the PLT section.
122 void
123 init(Layout* layout);
124
125 // Add an entry to the PLT.
126 void
127 add_entry(Symbol_table*, Layout*, Symbol* gsym);
128
129 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
130 unsigned int
131 add_local_ifunc_entry(Symbol_table* symtab, Layout*,
132 Sized_relobj_file<size, false>* relobj,
133 unsigned int local_sym_index);
134
135 // Add the relocation for a PLT entry.
136 void
137 add_relocation(Symbol_table*, Layout*, Symbol* gsym,
138 unsigned int got_offset);
139
140 // Add the reserved TLSDESC_PLT entry to the PLT.
141 void
142 reserve_tlsdesc_entry(unsigned int got_offset)
143 { this->tlsdesc_got_offset_ = got_offset; }
144
145 // Return true if a TLSDESC_PLT entry has been reserved.
146 bool
147 has_tlsdesc_entry() const
148 { return this->tlsdesc_got_offset_ != -1U; }
149
150 // Return the GOT offset for the reserved TLSDESC_PLT entry.
151 unsigned int
152 get_tlsdesc_got_offset() const
153 { return this->tlsdesc_got_offset_; }
154
155 // Return the offset of the reserved TLSDESC_PLT entry.
156 unsigned int
157 get_tlsdesc_plt_offset() const
158 {
159 return ((this->count_ + this->irelative_count_ + 1)
160 * this->get_plt_entry_size());
161 }
162
163 // Return the .rela.plt section data.
164 Reloc_section*
165 rela_plt()
166 { return this->rel_; }
167
168 // Return where the TLSDESC relocations should go.
169 Reloc_section*
170 rela_tlsdesc(Layout*);
171
172 // Return where the IRELATIVE relocations should go in the PLT
173 // relocations.
174 Reloc_section*
175 rela_irelative(Symbol_table*, Layout*);
176
177 // Return whether we created a section for IRELATIVE relocations.
178 bool
179 has_irelative_section() const
180 { return this->irelative_rel_ != NULL; }
181
182 // Get count of regular PLT entries.
183 unsigned int
184 regular_count() const
185 { return this->count_; }
186
187 // Return the total number of PLT entries.
188 unsigned int
189 entry_count() const
190 { return this->count_ + this->irelative_count_; }
191
192 // Return the offset of the first non-reserved PLT entry.
193 unsigned int
194 first_plt_entry_offset()
195 { return this->get_plt_entry_size(); }
196
197 // Return the size of a PLT entry.
198 unsigned int
199 get_plt_entry_size() const
200 { return this->do_get_plt_entry_size(); }
201
202 // Reserve a slot in the PLT for an existing symbol in an incremental update.
203 void
204 reserve_slot(unsigned int plt_index)
205 {
206 this->free_list_.remove((plt_index + 1) * this->get_plt_entry_size(),
207 (plt_index + 2) * this->get_plt_entry_size());
208 }
209
210 // Return the PLT address to use for a global symbol.
211 uint64_t
212 address_for_global(const Symbol* sym)
213 { return do_address_for_global(sym); }
214
215 // Return the PLT address to use for a local symbol.
216 uint64_t
217 address_for_local(const Relobj* obj, unsigned int symndx)
218 { return do_address_for_local(obj, symndx); }
219
220 // Add .eh_frame information for the PLT.
221 void
222 add_eh_frame(Layout* layout)
223 { this->do_add_eh_frame(layout); }
224
225 protected:
226 Output_data_got<64, false>*
227 got() const
228 { return this->got_; }
229
230 Output_data_got_plt_x86_64*
231 got_plt() const
232 { return this->got_plt_; }
233
234 Output_data_space*
235 got_irelative() const
236 { return this->got_irelative_; }
237
238 // Fill in the first PLT entry.
239 void
240 fill_first_plt_entry(unsigned char* pov,
241 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
242 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
243 { this->do_fill_first_plt_entry(pov, got_address, plt_address); }
244
245 // Fill in a normal PLT entry. Returns the offset into the entry that
246 // should be the initial GOT slot value.
247 unsigned int
248 fill_plt_entry(unsigned char* pov,
249 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
250 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
251 unsigned int got_offset,
252 unsigned int plt_offset,
253 unsigned int plt_index)
254 {
255 return this->do_fill_plt_entry(pov, got_address, plt_address,
256 got_offset, plt_offset, plt_index);
257 }
258
259 // Fill in the reserved TLSDESC PLT entry.
260 void
261 fill_tlsdesc_entry(unsigned char* pov,
262 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
263 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
264 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
265 unsigned int tlsdesc_got_offset,
266 unsigned int plt_offset)
267 {
268 this->do_fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
269 tlsdesc_got_offset, plt_offset);
270 }
271
272 virtual unsigned int
273 do_get_plt_entry_size() const = 0;
274
275 virtual void
276 do_fill_first_plt_entry(unsigned char* pov,
277 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
278 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr)
279 = 0;
280
281 virtual unsigned int
282 do_fill_plt_entry(unsigned char* pov,
283 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
284 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
285 unsigned int got_offset,
286 unsigned int plt_offset,
287 unsigned int plt_index) = 0;
288
289 virtual void
290 do_fill_tlsdesc_entry(unsigned char* pov,
291 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
292 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
293 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
294 unsigned int tlsdesc_got_offset,
295 unsigned int plt_offset) = 0;
296
297 // Return the PLT address to use for a global symbol.
298 virtual uint64_t
299 do_address_for_global(const Symbol* sym);
300
301 // Return the PLT address to use for a local symbol.
302 virtual uint64_t
303 do_address_for_local(const Relobj* obj, unsigned int symndx);
304
305 virtual void
306 do_add_eh_frame(Layout* layout) = 0;
307
308 void
309 do_adjust_output_section(Output_section* os);
310
311 // Write to a map file.
312 void
313 do_print_to_mapfile(Mapfile* mapfile) const
314 { mapfile->print_output_data(this, _("** PLT")); }
315
316 // The CIE of the .eh_frame unwind information for the PLT.
317 static const int plt_eh_frame_cie_size = 16;
318 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
319
320 private:
321 // Set the final size.
322 void
323 set_final_data_size();
324
325 // Write out the PLT data.
326 void
327 do_write(Output_file*);
328
329 // The reloc section.
330 Reloc_section* rel_;
331 // The TLSDESC relocs, if necessary. These must follow the regular
332 // PLT relocs.
333 Reloc_section* tlsdesc_rel_;
334 // The IRELATIVE relocs, if necessary. These must follow the
335 // regular PLT relocations and the TLSDESC relocations.
336 Reloc_section* irelative_rel_;
337 // The .got section.
338 Output_data_got<64, false>* got_;
339 // The .got.plt section.
340 Output_data_got_plt_x86_64* got_plt_;
341 // The part of the .got.plt section used for IRELATIVE relocs.
342 Output_data_space* got_irelative_;
343 // The number of PLT entries.
344 unsigned int count_;
345 // Number of PLT entries with R_X86_64_IRELATIVE relocs. These
346 // follow the regular PLT entries.
347 unsigned int irelative_count_;
348 // Offset of the reserved TLSDESC_GOT entry when needed.
349 unsigned int tlsdesc_got_offset_;
350 // List of available regions within the section, for incremental
351 // update links.
352 Free_list free_list_;
353 };
354
355 template<int size>
356 class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size>
357 {
358 public:
359 Output_data_plt_x86_64_standard(Layout* layout,
360 Output_data_got<64, false>* got,
361 Output_data_got_plt_x86_64* got_plt,
362 Output_data_space* got_irelative)
363 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
364 got, got_plt, got_irelative)
365 { }
366
367 Output_data_plt_x86_64_standard(Layout* layout,
368 Output_data_got<64, false>* got,
369 Output_data_got_plt_x86_64* got_plt,
370 Output_data_space* got_irelative,
371 unsigned int plt_count)
372 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
373 got, got_plt, got_irelative,
374 plt_count)
375 { }
376
377 protected:
378 virtual unsigned int
379 do_get_plt_entry_size() const
380 { return plt_entry_size; }
381
382 virtual void
383 do_add_eh_frame(Layout* layout)
384 {
385 layout->add_eh_frame_for_plt(this,
386 this->plt_eh_frame_cie,
387 this->plt_eh_frame_cie_size,
388 plt_eh_frame_fde,
389 plt_eh_frame_fde_size);
390 }
391
392 virtual void
393 do_fill_first_plt_entry(unsigned char* pov,
394 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
395 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr);
396
397 virtual unsigned int
398 do_fill_plt_entry(unsigned char* pov,
399 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
400 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
401 unsigned int got_offset,
402 unsigned int plt_offset,
403 unsigned int plt_index);
404
405 virtual void
406 do_fill_tlsdesc_entry(unsigned char* pov,
407 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
408 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
409 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
410 unsigned int tlsdesc_got_offset,
411 unsigned int plt_offset);
412
413 private:
414 // The size of an entry in the PLT.
415 static const int plt_entry_size = 16;
416
417 // The first entry in the PLT.
418 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
419 // procedure linkage table for both programs and shared objects."
420 static const unsigned char first_plt_entry[plt_entry_size];
421
422 // Other entries in the PLT for an executable.
423 static const unsigned char plt_entry[plt_entry_size];
424
425 // The reserved TLSDESC entry in the PLT for an executable.
426 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
427
428 // The .eh_frame unwind information for the PLT.
429 static const int plt_eh_frame_fde_size = 32;
430 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
431 };
432
433 class Output_data_plt_x86_64_bnd : public Output_data_plt_x86_64<64>
434 {
435 public:
436 Output_data_plt_x86_64_bnd(Layout* layout,
437 Output_data_got<64, false>* got,
438 Output_data_got_plt_x86_64* got_plt,
439 Output_data_space* got_irelative)
440 : Output_data_plt_x86_64<64>(layout, plt_entry_size,
441 got, got_plt, got_irelative),
442 aplt_offset_(0)
443 { }
444
445 Output_data_plt_x86_64_bnd(Layout* layout,
446 Output_data_got<64, false>* got,
447 Output_data_got_plt_x86_64* got_plt,
448 Output_data_space* got_irelative,
449 unsigned int plt_count)
450 : Output_data_plt_x86_64<64>(layout, plt_entry_size,
451 got, got_plt, got_irelative,
452 plt_count),
453 aplt_offset_(0)
454 { }
455
456 protected:
457 virtual unsigned int
458 do_get_plt_entry_size() const
459 { return plt_entry_size; }
460
461 // Return the PLT address to use for a global symbol.
462 uint64_t
463 do_address_for_global(const Symbol*);
464
465 // Return the PLT address to use for a local symbol.
466 uint64_t
467 do_address_for_local(const Relobj*, unsigned int symndx);
468
469 virtual void
470 do_add_eh_frame(Layout* layout)
471 {
472 layout->add_eh_frame_for_plt(this,
473 this->plt_eh_frame_cie,
474 this->plt_eh_frame_cie_size,
475 plt_eh_frame_fde,
476 plt_eh_frame_fde_size);
477 }
478
479 virtual void
480 do_fill_first_plt_entry(unsigned char* pov,
481 elfcpp::Elf_types<64>::Elf_Addr got_addr,
482 elfcpp::Elf_types<64>::Elf_Addr plt_addr);
483
484 virtual unsigned int
485 do_fill_plt_entry(unsigned char* pov,
486 elfcpp::Elf_types<64>::Elf_Addr got_address,
487 elfcpp::Elf_types<64>::Elf_Addr plt_address,
488 unsigned int got_offset,
489 unsigned int plt_offset,
490 unsigned int plt_index);
491
492 virtual void
493 do_fill_tlsdesc_entry(unsigned char* pov,
494 elfcpp::Elf_types<64>::Elf_Addr got_address,
495 elfcpp::Elf_types<64>::Elf_Addr plt_address,
496 elfcpp::Elf_types<64>::Elf_Addr got_base,
497 unsigned int tlsdesc_got_offset,
498 unsigned int plt_offset);
499
500 void
501 fill_aplt_entry(unsigned char* pov,
502 elfcpp::Elf_types<64>::Elf_Addr got_address,
503 elfcpp::Elf_types<64>::Elf_Addr plt_address,
504 unsigned int got_offset,
505 unsigned int plt_offset,
506 unsigned int plt_index);
507
508 private:
509 // Set the final size.
510 void
511 set_final_data_size();
512
513 // Write out the BND PLT data.
514 void
515 do_write(Output_file*);
516
517 // Offset of the Additional PLT (if using -z bndplt).
518 unsigned int aplt_offset_;
519
520 // The size of an entry in the PLT.
521 static const int plt_entry_size = 16;
522
523 // The size of an entry in the additional PLT.
524 static const int aplt_entry_size = 8;
525
526 // The first entry in the PLT.
527 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
528 // procedure linkage table for both programs and shared objects."
529 static const unsigned char first_plt_entry[plt_entry_size];
530
531 // Other entries in the PLT for an executable.
532 static const unsigned char plt_entry[plt_entry_size];
533
534 // Entries in the additional PLT.
535 static const unsigned char aplt_entry[aplt_entry_size];
536
537 // The reserved TLSDESC entry in the PLT for an executable.
538 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
539
540 // The .eh_frame unwind information for the PLT.
541 static const int plt_eh_frame_fde_size = 32;
542 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
543 };
544
545 // We use this PLT when Indirect Branch Tracking (IBT) is enabled.
546
547 template <int size>
548 class Output_data_plt_x86_64_ibt : public Output_data_plt_x86_64<size>
549 {
550 public:
551 Output_data_plt_x86_64_ibt(Layout* layout,
552 Output_data_got<64, false>* got,
553 Output_data_got_plt_x86_64* got_plt,
554 Output_data_space* got_irelative)
555 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
556 got, got_plt, got_irelative),
557 aplt_offset_(0)
558 { }
559
560 Output_data_plt_x86_64_ibt(Layout* layout,
561 Output_data_got<64, false>* got,
562 Output_data_got_plt_x86_64* got_plt,
563 Output_data_space* got_irelative,
564 unsigned int plt_count)
565 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
566 got, got_plt, got_irelative,
567 plt_count),
568 aplt_offset_(0)
569 { }
570
571 protected:
572 virtual unsigned int
573 do_get_plt_entry_size() const
574 { return plt_entry_size; }
575
576 // Return the PLT address to use for a global symbol.
577 uint64_t
578 do_address_for_global(const Symbol*);
579
580 // Return the PLT address to use for a local symbol.
581 uint64_t
582 do_address_for_local(const Relobj*, unsigned int symndx);
583
584 virtual void
585 do_add_eh_frame(Layout* layout)
586 {
587 layout->add_eh_frame_for_plt(this,
588 this->plt_eh_frame_cie,
589 this->plt_eh_frame_cie_size,
590 plt_eh_frame_fde,
591 plt_eh_frame_fde_size);
592 }
593
594 virtual void
595 do_fill_first_plt_entry(unsigned char* pov,
596 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
597 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr);
598
599 virtual unsigned int
600 do_fill_plt_entry(unsigned char* pov,
601 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
602 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
603 unsigned int got_offset,
604 unsigned int plt_offset,
605 unsigned int plt_index);
606
607 virtual void
608 do_fill_tlsdesc_entry(unsigned char* pov,
609 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
610 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
611 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
612 unsigned int tlsdesc_got_offset,
613 unsigned int plt_offset);
614
615 void
616 fill_aplt_entry(unsigned char* pov,
617 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
618 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
619 unsigned int got_offset,
620 unsigned int plt_offset,
621 unsigned int plt_index);
622
623 private:
624 // Set the final size.
625 void
626 set_final_data_size();
627
628 // Write out the BND PLT data.
629 void
630 do_write(Output_file*);
631
632 // Offset of the Additional PLT (if using -z bndplt).
633 unsigned int aplt_offset_;
634
635 // The size of an entry in the PLT.
636 static const int plt_entry_size = 16;
637
638 // The size of an entry in the additional PLT.
639 static const int aplt_entry_size = 16;
640
641 // The first entry in the PLT.
642 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
643 // procedure linkage table for both programs and shared objects."
644 static const unsigned char first_plt_entry[plt_entry_size];
645
646 // Other entries in the PLT for an executable.
647 static const unsigned char plt_entry[plt_entry_size];
648
649 // Entries in the additional PLT.
650 static const unsigned char aplt_entry[aplt_entry_size];
651
652 // The reserved TLSDESC entry in the PLT for an executable.
653 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
654
655 // The .eh_frame unwind information for the PLT.
656 static const int plt_eh_frame_fde_size = 32;
657 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
658 };
659
660 template<int size>
661 class Lazy_view
662 {
663 public:
664 Lazy_view(Sized_relobj_file<size, false>* object, unsigned int data_shndx)
665 : object_(object), data_shndx_(data_shndx), view_(NULL), view_size_(0)
666 { }
667
668 inline unsigned char
669 operator[](size_t offset)
670 {
671 if (this->view_ == NULL)
672 this->view_ = this->object_->section_contents(this->data_shndx_,
673 &this->view_size_,
674 true);
675 if (offset >= this->view_size_)
676 return 0;
677 return this->view_[offset];
678 }
679
680 private:
681 Sized_relobj_file<size, false>* object_;
682 unsigned int data_shndx_;
683 const unsigned char* view_;
684 section_size_type view_size_;
685 };
686
687 // The x86_64 target class.
688 // See the ABI at
689 // http://www.x86-64.org/documentation/abi.pdf
690 // TLS info comes from
691 // http://people.redhat.com/drepper/tls.pdf
692 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
693
694 template<int size>
695 class Target_x86_64 : public Sized_target<size, false>
696 {
697 public:
698 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
699 // uses only Elf64_Rela relocation entries with explicit addends."
700 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
701
702 Target_x86_64(const Target::Target_info* info = &x86_64_info)
703 : Sized_target<size, false>(info),
704 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
705 got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL),
706 rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY),
707 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
708 tls_base_symbol_defined_(false), isa_1_used_(0), isa_1_needed_(0),
709 feature_1_(0), object_isa_1_used_(0), object_feature_1_(0),
710 seen_first_object_(false)
711 { }
712
713 // Hook for a new output section.
714 void
715 do_new_output_section(Output_section*) const;
716
717 // Scan the relocations to look for symbol adjustments.
718 void
719 gc_process_relocs(Symbol_table* symtab,
720 Layout* layout,
721 Sized_relobj_file<size, false>* object,
722 unsigned int data_shndx,
723 unsigned int sh_type,
724 const unsigned char* prelocs,
725 size_t reloc_count,
726 Output_section* output_section,
727 bool needs_special_offset_handling,
728 size_t local_symbol_count,
729 const unsigned char* plocal_symbols);
730
731 // Scan the relocations to look for symbol adjustments.
732 void
733 scan_relocs(Symbol_table* symtab,
734 Layout* layout,
735 Sized_relobj_file<size, false>* object,
736 unsigned int data_shndx,
737 unsigned int sh_type,
738 const unsigned char* prelocs,
739 size_t reloc_count,
740 Output_section* output_section,
741 bool needs_special_offset_handling,
742 size_t local_symbol_count,
743 const unsigned char* plocal_symbols);
744
745 // Finalize the sections.
746 void
747 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
748
749 // Return the value to use for a dynamic which requires special
750 // treatment.
751 uint64_t
752 do_dynsym_value(const Symbol*) const;
753
754 // Relocate a section.
755 void
756 relocate_section(const Relocate_info<size, false>*,
757 unsigned int sh_type,
758 const unsigned char* prelocs,
759 size_t reloc_count,
760 Output_section* output_section,
761 bool needs_special_offset_handling,
762 unsigned char* view,
763 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
764 section_size_type view_size,
765 const Reloc_symbol_changes*);
766
767 // Scan the relocs during a relocatable link.
768 void
769 scan_relocatable_relocs(Symbol_table* symtab,
770 Layout* layout,
771 Sized_relobj_file<size, false>* object,
772 unsigned int data_shndx,
773 unsigned int sh_type,
774 const unsigned char* prelocs,
775 size_t reloc_count,
776 Output_section* output_section,
777 bool needs_special_offset_handling,
778 size_t local_symbol_count,
779 const unsigned char* plocal_symbols,
780 Relocatable_relocs*);
781
782 // Scan the relocs for --emit-relocs.
783 void
784 emit_relocs_scan(Symbol_table* symtab,
785 Layout* layout,
786 Sized_relobj_file<size, false>* object,
787 unsigned int data_shndx,
788 unsigned int sh_type,
789 const unsigned char* prelocs,
790 size_t reloc_count,
791 Output_section* output_section,
792 bool needs_special_offset_handling,
793 size_t local_symbol_count,
794 const unsigned char* plocal_syms,
795 Relocatable_relocs* rr);
796
797 // Emit relocations for a section.
798 void
799 relocate_relocs(
800 const Relocate_info<size, false>*,
801 unsigned int sh_type,
802 const unsigned char* prelocs,
803 size_t reloc_count,
804 Output_section* output_section,
805 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
806 unsigned char* view,
807 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
808 section_size_type view_size,
809 unsigned char* reloc_view,
810 section_size_type reloc_view_size);
811
812 // Return a string used to fill a code section with nops.
813 std::string
814 do_code_fill(section_size_type length) const;
815
816 // Return whether SYM is defined by the ABI.
817 bool
818 do_is_defined_by_abi(const Symbol* sym) const
819 { return strcmp(sym->name(), "__tls_get_addr") == 0; }
820
821 // Return the symbol index to use for a target specific relocation.
822 // The only target specific relocation is R_X86_64_TLSDESC for a
823 // local symbol, which is an absolute reloc.
824 unsigned int
825 do_reloc_symbol_index(void*, unsigned int r_type) const
826 {
827 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
828 return 0;
829 }
830
831 // Return the addend to use for a target specific relocation.
832 uint64_t
833 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
834
835 // Return the PLT section.
836 uint64_t
837 do_plt_address_for_global(const Symbol* gsym) const
838 { return this->plt_section()->address_for_global(gsym); }
839
840 uint64_t
841 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
842 { return this->plt_section()->address_for_local(relobj, symndx); }
843
844 // This function should be defined in targets that can use relocation
845 // types to determine (implemented in local_reloc_may_be_function_pointer
846 // and global_reloc_may_be_function_pointer)
847 // if a function's pointer is taken. ICF uses this in safe mode to only
848 // fold those functions whose pointer is defintely not taken. For x86_64
849 // pie binaries, safe ICF cannot be done by looking at only relocation
850 // types, and for certain cases (e.g. R_X86_64_PC32), the instruction
851 // opcode is checked as well to distinguish a function call from taking
852 // a function's pointer.
853 bool
854 do_can_check_for_function_pointers() const
855 { return true; }
856
857 // Return the base for a DW_EH_PE_datarel encoding.
858 uint64_t
859 do_ehframe_datarel_base() const;
860
861 // Adjust -fsplit-stack code which calls non-split-stack code.
862 void
863 do_calls_non_split(Relobj* object, unsigned int shndx,
864 section_offset_type fnoffset, section_size_type fnsize,
865 const unsigned char* prelocs, size_t reloc_count,
866 unsigned char* view, section_size_type view_size,
867 std::string* from, std::string* to) const;
868
869 // Return the size of the GOT section.
870 section_size_type
871 got_size() const
872 {
873 gold_assert(this->got_ != NULL);
874 return this->got_->data_size();
875 }
876
877 // Return the number of entries in the GOT.
878 unsigned int
879 got_entry_count() const
880 {
881 if (this->got_ == NULL)
882 return 0;
883 return this->got_size() / 8;
884 }
885
886 // Return the number of entries in the PLT.
887 unsigned int
888 plt_entry_count() const;
889
890 // Return the offset of the first non-reserved PLT entry.
891 unsigned int
892 first_plt_entry_offset() const;
893
894 // Return the size of each PLT entry.
895 unsigned int
896 plt_entry_size() const;
897
898 // Return the size of each GOT entry.
899 unsigned int
900 got_entry_size() const
901 { return 8; };
902
903 // Create the GOT section for an incremental update.
904 Output_data_got_base*
905 init_got_plt_for_update(Symbol_table* symtab,
906 Layout* layout,
907 unsigned int got_count,
908 unsigned int plt_count);
909
910 // Reserve a GOT entry for a local symbol, and regenerate any
911 // necessary dynamic relocations.
912 void
913 reserve_local_got_entry(unsigned int got_index,
914 Sized_relobj<size, false>* obj,
915 unsigned int r_sym,
916 unsigned int got_type);
917
918 // Reserve a GOT entry for a global symbol, and regenerate any
919 // necessary dynamic relocations.
920 void
921 reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
922 unsigned int got_type);
923
924 // Register an existing PLT entry for a global symbol.
925 void
926 register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index,
927 Symbol* gsym);
928
929 // Force a COPY relocation for a given symbol.
930 void
931 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t);
932
933 // Apply an incremental relocation.
934 void
935 apply_relocation(const Relocate_info<size, false>* relinfo,
936 typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
937 unsigned int r_type,
938 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
939 const Symbol* gsym,
940 unsigned char* view,
941 typename elfcpp::Elf_types<size>::Elf_Addr address,
942 section_size_type view_size);
943
944 // Add a new reloc argument, returning the index in the vector.
945 size_t
946 add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym)
947 {
948 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
949 return this->tlsdesc_reloc_info_.size() - 1;
950 }
951
952 Output_data_plt_x86_64<size>*
953 make_data_plt(Layout* layout,
954 Output_data_got<64, false>* got,
955 Output_data_got_plt_x86_64* got_plt,
956 Output_data_space* got_irelative)
957 {
958 return this->do_make_data_plt(layout, got, got_plt, got_irelative);
959 }
960
961 Output_data_plt_x86_64<size>*
962 make_data_plt(Layout* layout,
963 Output_data_got<64, false>* got,
964 Output_data_got_plt_x86_64* got_plt,
965 Output_data_space* got_irelative,
966 unsigned int plt_count)
967 {
968 return this->do_make_data_plt(layout, got, got_plt, got_irelative,
969 plt_count);
970 }
971
972 virtual Output_data_plt_x86_64<size>*
973 do_make_data_plt(Layout* layout,
974 Output_data_got<64, false>* got,
975 Output_data_got_plt_x86_64* got_plt,
976 Output_data_space* got_irelative);
977
978 virtual Output_data_plt_x86_64<size>*
979 do_make_data_plt(Layout* layout,
980 Output_data_got<64, false>* got,
981 Output_data_got_plt_x86_64* got_plt,
982 Output_data_space* got_irelative,
983 unsigned int plt_count);
984
985 private:
986 // The class which scans relocations.
987 class Scan
988 {
989 public:
990 Scan()
991 : issued_non_pic_error_(false)
992 { }
993
994 static inline int
995 get_reference_flags(unsigned int r_type);
996
997 inline void
998 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
999 Sized_relobj_file<size, false>* object,
1000 unsigned int data_shndx,
1001 Output_section* output_section,
1002 const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
1003 const elfcpp::Sym<size, false>& lsym,
1004 bool is_discarded);
1005
1006 inline void
1007 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
1008 Sized_relobj_file<size, false>* object,
1009 unsigned int data_shndx,
1010 Output_section* output_section,
1011 const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
1012 Symbol* gsym);
1013
1014 inline bool
1015 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
1016 Target_x86_64* target,
1017 Sized_relobj_file<size, false>* object,
1018 unsigned int data_shndx,
1019 Output_section* output_section,
1020 const elfcpp::Rela<size, false>& reloc,
1021 unsigned int r_type,
1022 const elfcpp::Sym<size, false>& lsym);
1023
1024 inline bool
1025 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
1026 Target_x86_64* target,
1027 Sized_relobj_file<size, false>* object,
1028 unsigned int data_shndx,
1029 Output_section* output_section,
1030 const elfcpp::Rela<size, false>& reloc,
1031 unsigned int r_type,
1032 Symbol* gsym);
1033
1034 private:
1035 static void
1036 unsupported_reloc_local(Sized_relobj_file<size, false>*,
1037 unsigned int r_type);
1038
1039 static void
1040 unsupported_reloc_global(Sized_relobj_file<size, false>*,
1041 unsigned int r_type, Symbol*);
1042
1043 void
1044 check_non_pic(Relobj*, unsigned int r_type, Symbol*);
1045
1046 inline bool
1047 possible_function_pointer_reloc(Sized_relobj_file<size, false>* src_obj,
1048 unsigned int src_indx,
1049 unsigned int r_offset,
1050 unsigned int r_type);
1051
1052 bool
1053 reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*,
1054 unsigned int r_type);
1055
1056 // Whether we have issued an error about a non-PIC compilation.
1057 bool issued_non_pic_error_;
1058 };
1059
1060 // The class which implements relocation.
1061 class Relocate
1062 {
1063 public:
1064 Relocate()
1065 : skip_call_tls_get_addr_(false)
1066 { }
1067
1068 ~Relocate()
1069 {
1070 if (this->skip_call_tls_get_addr_)
1071 {
1072 // FIXME: This needs to specify the location somehow.
1073 gold_error(_("missing expected TLS relocation"));
1074 }
1075 }
1076
1077 // Do a relocation. Return false if the caller should not issue
1078 // any warnings about this relocation.
1079 inline bool
1080 relocate(const Relocate_info<size, false>*, unsigned int,
1081 Target_x86_64*, Output_section*, size_t, const unsigned char*,
1082 const Sized_symbol<size>*, const Symbol_value<size>*,
1083 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
1084 section_size_type);
1085
1086 private:
1087 // Do a TLS relocation.
1088 inline void
1089 relocate_tls(const Relocate_info<size, false>*, Target_x86_64*,
1090 size_t relnum, const elfcpp::Rela<size, false>&,
1091 unsigned int r_type, const Sized_symbol<size>*,
1092 const Symbol_value<size>*,
1093 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
1094 section_size_type);
1095
1096 // Do a TLS General-Dynamic to Initial-Exec transition.
1097 inline void
1098 tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
1099 const elfcpp::Rela<size, false>&, unsigned int r_type,
1100 typename elfcpp::Elf_types<size>::Elf_Addr value,
1101 unsigned char* view,
1102 typename elfcpp::Elf_types<size>::Elf_Addr,
1103 section_size_type view_size);
1104
1105 // Do a TLS General-Dynamic to Local-Exec transition.
1106 inline void
1107 tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
1108 Output_segment* tls_segment,
1109 const elfcpp::Rela<size, false>&, unsigned int r_type,
1110 typename elfcpp::Elf_types<size>::Elf_Addr value,
1111 unsigned char* view,
1112 section_size_type view_size);
1113
1114 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
1115 inline void
1116 tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
1117 const elfcpp::Rela<size, false>&, unsigned int r_type,
1118 typename elfcpp::Elf_types<size>::Elf_Addr value,
1119 unsigned char* view,
1120 typename elfcpp::Elf_types<size>::Elf_Addr,
1121 section_size_type view_size);
1122
1123 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
1124 inline void
1125 tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
1126 Output_segment* tls_segment,
1127 const elfcpp::Rela<size, false>&, unsigned int r_type,
1128 typename elfcpp::Elf_types<size>::Elf_Addr value,
1129 unsigned char* view,
1130 section_size_type view_size);
1131
1132 // Do a TLS Local-Dynamic to Local-Exec transition.
1133 inline void
1134 tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum,
1135 Output_segment* tls_segment,
1136 const elfcpp::Rela<size, false>&, unsigned int r_type,
1137 typename elfcpp::Elf_types<size>::Elf_Addr value,
1138 unsigned char* view,
1139 section_size_type view_size);
1140
1141 // Do a TLS Initial-Exec to Local-Exec transition.
1142 static inline void
1143 tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum,
1144 Output_segment* tls_segment,
1145 const elfcpp::Rela<size, false>&, unsigned int r_type,
1146 typename elfcpp::Elf_types<size>::Elf_Addr value,
1147 unsigned char* view,
1148 section_size_type view_size);
1149
1150 // This is set if we should skip the next reloc, which should be a
1151 // PLT32 reloc against ___tls_get_addr.
1152 bool skip_call_tls_get_addr_;
1153 };
1154
1155 // Check if relocation against this symbol is a candidate for
1156 // conversion from
1157 // mov foo@GOTPCREL(%rip), %reg
1158 // to lea foo(%rip), %reg.
1159 template<class View_type>
1160 static inline bool
1161 can_convert_mov_to_lea(const Symbol* gsym, unsigned int r_type,
1162 size_t r_offset, View_type* view)
1163 {
1164 gold_assert(gsym != NULL);
1165 // We cannot do the conversion unless it's one of these relocations.
1166 if (r_type != elfcpp::R_X86_64_GOTPCREL
1167 && r_type != elfcpp::R_X86_64_GOTPCRELX
1168 && r_type != elfcpp::R_X86_64_REX_GOTPCRELX)
1169 return false;
1170 // We cannot convert references to IFUNC symbols, or to symbols that
1171 // are not local to the current module.
1172 // We can't do predefined symbols because they may become undefined
1173 // (e.g., __ehdr_start when the headers aren't mapped to a segment).
1174 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1175 || gsym->is_undefined()
1176 || gsym->is_predefined()
1177 || gsym->is_from_dynobj()
1178 || gsym->is_preemptible())
1179 return false;
1180 // If we are building a shared object and the symbol is protected, we may
1181 // need to go through the GOT.
1182 if (parameters->options().shared()
1183 && gsym->visibility() == elfcpp::STV_PROTECTED)
1184 return false;
1185 // We cannot convert references to the _DYNAMIC symbol.
1186 if (strcmp(gsym->name(), "_DYNAMIC") == 0)
1187 return false;
1188 // Check for a MOV opcode.
1189 return (*view)[r_offset - 2] == 0x8b;
1190 }
1191
1192 // Convert
1193 // callq *foo@GOTPCRELX(%rip) to
1194 // addr32 callq foo
1195 // and jmpq *foo@GOTPCRELX(%rip) to
1196 // jmpq foo
1197 // nop
1198 template<class View_type>
1199 static inline bool
1200 can_convert_callq_to_direct(const Symbol* gsym, unsigned int r_type,
1201 size_t r_offset, View_type* view)
1202 {
1203 gold_assert(gsym != NULL);
1204 // We cannot do the conversion unless it's a GOTPCRELX relocation.
1205 if (r_type != elfcpp::R_X86_64_GOTPCRELX)
1206 return false;
1207 // We cannot convert references to IFUNC symbols, or to symbols that
1208 // are not local to the current module.
1209 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1210 || gsym->is_undefined ()
1211 || gsym->is_from_dynobj()
1212 || gsym->is_preemptible())
1213 return false;
1214 // Check for a CALLQ or JMPQ opcode.
1215 return ((*view)[r_offset - 2] == 0xff
1216 && ((*view)[r_offset - 1] == 0x15
1217 || (*view)[r_offset - 1] == 0x25));
1218 }
1219
1220 // Adjust TLS relocation type based on the options and whether this
1221 // is a local symbol.
1222 static tls::Tls_optimization
1223 optimize_tls_reloc(bool is_final, int r_type);
1224
1225 // Get the GOT section, creating it if necessary.
1226 Output_data_got<64, false>*
1227 got_section(Symbol_table*, Layout*);
1228
1229 // Get the GOT PLT section.
1230 Output_data_got_plt_x86_64*
1231 got_plt_section() const
1232 {
1233 gold_assert(this->got_plt_ != NULL);
1234 return this->got_plt_;
1235 }
1236
1237 // Get the GOT section for TLSDESC entries.
1238 Output_data_got<64, false>*
1239 got_tlsdesc_section() const
1240 {
1241 gold_assert(this->got_tlsdesc_ != NULL);
1242 return this->got_tlsdesc_;
1243 }
1244
1245 // Create the PLT section.
1246 void
1247 make_plt_section(Symbol_table* symtab, Layout* layout);
1248
1249 // Create a PLT entry for a global symbol.
1250 void
1251 make_plt_entry(Symbol_table*, Layout*, Symbol*);
1252
1253 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
1254 void
1255 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
1256 Sized_relobj_file<size, false>* relobj,
1257 unsigned int local_sym_index);
1258
1259 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1260 void
1261 define_tls_base_symbol(Symbol_table*, Layout*);
1262
1263 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1264 void
1265 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
1266
1267 // Create a GOT entry for the TLS module index.
1268 unsigned int
1269 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1270 Sized_relobj_file<size, false>* object);
1271
1272 // Get the PLT section.
1273 Output_data_plt_x86_64<size>*
1274 plt_section() const
1275 {
1276 gold_assert(this->plt_ != NULL);
1277 return this->plt_;
1278 }
1279
1280 // Get the dynamic reloc section, creating it if necessary.
1281 Reloc_section*
1282 rela_dyn_section(Layout*);
1283
1284 // Get the section to use for TLSDESC relocations.
1285 Reloc_section*
1286 rela_tlsdesc_section(Layout*) const;
1287
1288 // Get the section to use for IRELATIVE relocations.
1289 Reloc_section*
1290 rela_irelative_section(Layout*);
1291
1292 // Add a potential copy relocation.
1293 void
1294 copy_reloc(Symbol_table* symtab, Layout* layout,
1295 Sized_relobj_file<size, false>* object,
1296 unsigned int shndx, Output_section* output_section,
1297 Symbol* sym, const elfcpp::Rela<size, false>& reloc)
1298 {
1299 unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info());
1300 this->copy_relocs_.copy_reloc(symtab, layout,
1301 symtab->get_sized_symbol<size>(sym),
1302 object, shndx, output_section,
1303 r_type, reloc.get_r_offset(),
1304 reloc.get_r_addend(),
1305 this->rela_dyn_section(layout));
1306 }
1307
1308 // Record a target-specific program property in the .note.gnu.property
1309 // section.
1310 void
1311 record_gnu_property(unsigned int, unsigned int, size_t,
1312 const unsigned char*, const Object*);
1313
1314 // Merge the target-specific program properties from the current object.
1315 void
1316 merge_gnu_properties(const Object*);
1317
1318 // Finalize the target-specific program properties and add them back to
1319 // the layout.
1320 void
1321 do_finalize_gnu_properties(Layout*) const;
1322
1323 // Information about this specific target which we pass to the
1324 // general Target structure.
1325 static const Target::Target_info x86_64_info;
1326
1327 // The types of GOT entries needed for this platform.
1328 // These values are exposed to the ABI in an incremental link.
1329 // Do not renumber existing values without changing the version
1330 // number of the .gnu_incremental_inputs section.
1331 enum Got_type
1332 {
1333 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
1334 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset
1335 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
1336 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
1337 };
1338
1339 // This type is used as the argument to the target specific
1340 // relocation routines. The only target specific reloc is
1341 // R_X86_64_TLSDESC against a local symbol.
1342 struct Tlsdesc_info
1343 {
1344 Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym)
1345 : object(a_object), r_sym(a_r_sym)
1346 { }
1347
1348 // The object in which the local symbol is defined.
1349 Sized_relobj_file<size, false>* object;
1350 // The local symbol index in the object.
1351 unsigned int r_sym;
1352 };
1353
1354 // The GOT section.
1355 Output_data_got<64, false>* got_;
1356 // The PLT section.
1357 Output_data_plt_x86_64<size>* plt_;
1358 // The GOT PLT section.
1359 Output_data_got_plt_x86_64* got_plt_;
1360 // The GOT section for IRELATIVE relocations.
1361 Output_data_space* got_irelative_;
1362 // The GOT section for TLSDESC relocations.
1363 Output_data_got<64, false>* got_tlsdesc_;
1364 // The _GLOBAL_OFFSET_TABLE_ symbol.
1365 Symbol* global_offset_table_;
1366 // The dynamic reloc section.
1367 Reloc_section* rela_dyn_;
1368 // The section to use for IRELATIVE relocs.
1369 Reloc_section* rela_irelative_;
1370 // Relocs saved to avoid a COPY reloc.
1371 Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_;
1372 // Offset of the GOT entry for the TLS module index.
1373 unsigned int got_mod_index_offset_;
1374 // We handle R_X86_64_TLSDESC against a local symbol as a target
1375 // specific relocation. Here we store the object and local symbol
1376 // index for the relocation.
1377 std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
1378 // True if the _TLS_MODULE_BASE_ symbol has been defined.
1379 bool tls_base_symbol_defined_;
1380 // Target-specific program properties, from .note.gnu.property section.
1381 // Each bit represents a specific feature.
1382 uint32_t isa_1_used_;
1383 uint32_t isa_1_needed_;
1384 uint32_t feature_1_;
1385 // Target-specific properties from the current object.
1386 // These bits get ORed into ISA_1_USED_ after all properties for the object
1387 // have been processed. But if either is all zeroes (as when the property
1388 // is absent from an object), the result should be all zeroes.
1389 // (See PR ld/23486.)
1390 uint32_t object_isa_1_used_;
1391 // These bits get ANDed into FEATURE_1_ after all properties for the object
1392 // have been processed.
1393 uint32_t object_feature_1_;
1394 // Whether we have seen our first object, for use in initializing FEATURE_1_.
1395 bool seen_first_object_;
1396 };
1397
1398 template<>
1399 const Target::Target_info Target_x86_64<64>::x86_64_info =
1400 {
1401 64, // size
1402 false, // is_big_endian
1403 elfcpp::EM_X86_64, // machine_code
1404 false, // has_make_symbol
1405 false, // has_resolve
1406 true, // has_code_fill
1407 true, // is_default_stack_executable
1408 true, // can_icf_inline_merge_sections
1409 '\0', // wrap_char
1410 "/lib/ld64.so.1", // program interpreter
1411 0x400000, // default_text_segment_address
1412 0x1000, // abi_pagesize (overridable by -z max-page-size)
1413 0x1000, // common_pagesize (overridable by -z common-page-size)
1414 false, // isolate_execinstr
1415 0, // rosegment_gap
1416 elfcpp::SHN_UNDEF, // small_common_shndx
1417 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
1418 0, // small_common_section_flags
1419 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
1420 NULL, // attributes_section
1421 NULL, // attributes_vendor
1422 "_start", // entry_symbol_name
1423 32, // hash_entry_size
1424 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type
1425 };
1426
1427 template<>
1428 const Target::Target_info Target_x86_64<32>::x86_64_info =
1429 {
1430 32, // size
1431 false, // is_big_endian
1432 elfcpp::EM_X86_64, // machine_code
1433 false, // has_make_symbol
1434 false, // has_resolve
1435 true, // has_code_fill
1436 true, // is_default_stack_executable
1437 true, // can_icf_inline_merge_sections
1438 '\0', // wrap_char
1439 "/libx32/ldx32.so.1", // program interpreter
1440 0x400000, // default_text_segment_address
1441 0x1000, // abi_pagesize (overridable by -z max-page-size)
1442 0x1000, // common_pagesize (overridable by -z common-page-size)
1443 false, // isolate_execinstr
1444 0, // rosegment_gap
1445 elfcpp::SHN_UNDEF, // small_common_shndx
1446 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
1447 0, // small_common_section_flags
1448 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
1449 NULL, // attributes_section
1450 NULL, // attributes_vendor
1451 "_start", // entry_symbol_name
1452 32, // hash_entry_size
1453 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type
1454 };
1455
1456 // This is called when a new output section is created. This is where
1457 // we handle the SHF_X86_64_LARGE.
1458
1459 template<int size>
1460 void
1461 Target_x86_64<size>::do_new_output_section(Output_section* os) const
1462 {
1463 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
1464 os->set_is_large_section();
1465 }
1466
1467 // Get the GOT section, creating it if necessary.
1468
1469 template<int size>
1470 Output_data_got<64, false>*
1471 Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout)
1472 {
1473 if (this->got_ == NULL)
1474 {
1475 gold_assert(symtab != NULL && layout != NULL);
1476
1477 // When using -z now, we can treat .got.plt as a relro section.
1478 // Without -z now, it is modified after program startup by lazy
1479 // PLT relocations.
1480 bool is_got_plt_relro = parameters->options().now();
1481 Output_section_order got_order = (is_got_plt_relro
1482 ? ORDER_RELRO
1483 : ORDER_RELRO_LAST);
1484 Output_section_order got_plt_order = (is_got_plt_relro
1485 ? ORDER_RELRO
1486 : ORDER_NON_RELRO_FIRST);
1487
1488 this->got_ = new Output_data_got<64, false>();
1489
1490 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
1491 (elfcpp::SHF_ALLOC
1492 | elfcpp::SHF_WRITE),
1493 this->got_, got_order, true);
1494
1495 this->got_plt_ = new Output_data_got_plt_x86_64(layout);
1496 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1497 (elfcpp::SHF_ALLOC
1498 | elfcpp::SHF_WRITE),
1499 this->got_plt_, got_plt_order,
1500 is_got_plt_relro);
1501
1502 // The first three entries are reserved.
1503 this->got_plt_->set_current_data_size(3 * 8);
1504
1505 if (!is_got_plt_relro)
1506 {
1507 // Those bytes can go into the relro segment.
1508 layout->increase_relro(3 * 8);
1509 }
1510
1511 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
1512 this->global_offset_table_ =
1513 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
1514 Symbol_table::PREDEFINED,
1515 this->got_plt_,
1516 0, 0, elfcpp::STT_OBJECT,
1517 elfcpp::STB_LOCAL,
1518 elfcpp::STV_HIDDEN, 0,
1519 false, false);
1520
1521 // If there are any IRELATIVE relocations, they get GOT entries
1522 // in .got.plt after the jump slot entries.
1523 this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT");
1524 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1525 (elfcpp::SHF_ALLOC
1526 | elfcpp::SHF_WRITE),
1527 this->got_irelative_,
1528 got_plt_order, is_got_plt_relro);
1529
1530 // If there are any TLSDESC relocations, they get GOT entries in
1531 // .got.plt after the jump slot and IRELATIVE entries.
1532 this->got_tlsdesc_ = new Output_data_got<64, false>();
1533 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1534 (elfcpp::SHF_ALLOC
1535 | elfcpp::SHF_WRITE),
1536 this->got_tlsdesc_,
1537 got_plt_order, is_got_plt_relro);
1538 }
1539
1540 return this->got_;
1541 }
1542
1543 // Get the dynamic reloc section, creating it if necessary.
1544
1545 template<int size>
1546 typename Target_x86_64<size>::Reloc_section*
1547 Target_x86_64<size>::rela_dyn_section(Layout* layout)
1548 {
1549 if (this->rela_dyn_ == NULL)
1550 {
1551 gold_assert(layout != NULL);
1552 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
1553 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
1554 elfcpp::SHF_ALLOC, this->rela_dyn_,
1555 ORDER_DYNAMIC_RELOCS, false);
1556 }
1557 return this->rela_dyn_;
1558 }
1559
1560 // Get the section to use for IRELATIVE relocs, creating it if
1561 // necessary. These go in .rela.dyn, but only after all other dynamic
1562 // relocations. They need to follow the other dynamic relocations so
1563 // that they can refer to global variables initialized by those
1564 // relocs.
1565
1566 template<int size>
1567 typename Target_x86_64<size>::Reloc_section*
1568 Target_x86_64<size>::rela_irelative_section(Layout* layout)
1569 {
1570 if (this->rela_irelative_ == NULL)
1571 {
1572 // Make sure we have already created the dynamic reloc section.
1573 this->rela_dyn_section(layout);
1574 this->rela_irelative_ = new Reloc_section(false);
1575 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
1576 elfcpp::SHF_ALLOC, this->rela_irelative_,
1577 ORDER_DYNAMIC_RELOCS, false);
1578 gold_assert(this->rela_dyn_->output_section()
1579 == this->rela_irelative_->output_section());
1580 }
1581 return this->rela_irelative_;
1582 }
1583
1584 // Record a target-specific program property from the .note.gnu.property
1585 // section.
1586 template<int size>
1587 void
1588 Target_x86_64<size>::record_gnu_property(
1589 unsigned int, unsigned int pr_type,
1590 size_t pr_datasz, const unsigned char* pr_data,
1591 const Object* object)
1592 {
1593 uint32_t val = 0;
1594
1595 switch (pr_type)
1596 {
1597 case elfcpp::GNU_PROPERTY_X86_ISA_1_USED:
1598 case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED:
1599 case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND:
1600 if (pr_datasz != 4)
1601 {
1602 gold_warning(_("%s: corrupt .note.gnu.property section "
1603 "(pr_datasz for property %d is not 4)"),
1604 object->name().c_str(), pr_type);
1605 return;
1606 }
1607 val = elfcpp::Swap<32, false>::readval(pr_data);
1608 break;
1609 default:
1610 gold_warning(_("%s: unknown program property type 0x%x "
1611 "in .note.gnu.property section"),
1612 object->name().c_str(), pr_type);
1613 break;
1614 }
1615
1616 switch (pr_type)
1617 {
1618 case elfcpp::GNU_PROPERTY_X86_ISA_1_USED:
1619 this->object_isa_1_used_ |= val;
1620 break;
1621 case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED:
1622 this->isa_1_needed_ |= val;
1623 break;
1624 case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND:
1625 // If we see multiple feature props in one object, OR them together.
1626 this->object_feature_1_ |= val;
1627 break;
1628 }
1629 }
1630
1631 // Merge the target-specific program properties from the current object.
1632 template<int size>
1633 void
1634 Target_x86_64<size>::merge_gnu_properties(const Object*)
1635 {
1636 if (this->seen_first_object_)
1637 {
1638 // If any object is missing the ISA_1_USED property, we must omit
1639 // it from the output file.
1640 if (this->object_isa_1_used_ == 0)
1641 this->isa_1_used_ = 0;
1642 else if (this->isa_1_used_ != 0)
1643 this->isa_1_used_ |= this->object_isa_1_used_;
1644 this->feature_1_ &= this->object_feature_1_;
1645 }
1646 else
1647 {
1648 this->isa_1_used_ = this->object_isa_1_used_;
1649 this->feature_1_ = this->object_feature_1_;
1650 this->seen_first_object_ = true;
1651 }
1652 this->object_isa_1_used_ = 0;
1653 this->object_feature_1_ = 0;
1654 }
1655
1656 static inline void
1657 add_property(Layout* layout, unsigned int pr_type, uint32_t val)
1658 {
1659 unsigned char buf[4];
1660 elfcpp::Swap<32, false>::writeval(buf, val);
1661 layout->add_gnu_property(elfcpp::NT_GNU_PROPERTY_TYPE_0, pr_type, 4, buf);
1662 }
1663
1664 // Finalize the target-specific program properties and add them back to
1665 // the layout.
1666 template<int size>
1667 void
1668 Target_x86_64<size>::do_finalize_gnu_properties(Layout* layout) const
1669 {
1670 if (this->isa_1_used_ != 0)
1671 add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_USED,
1672 this->isa_1_used_);
1673 if (this->isa_1_needed_ != 0)
1674 add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED,
1675 this->isa_1_needed_);
1676 if (this->feature_1_ != 0)
1677 add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND,
1678 this->feature_1_);
1679 }
1680
1681 // Write the first three reserved words of the .got.plt section.
1682 // The remainder of the section is written while writing the PLT
1683 // in Output_data_plt_i386::do_write.
1684
1685 void
1686 Output_data_got_plt_x86_64::do_write(Output_file* of)
1687 {
1688 // The first entry in the GOT is the address of the .dynamic section
1689 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1690 // We saved space for them when we created the section in
1691 // Target_x86_64::got_section.
1692 const off_t got_file_offset = this->offset();
1693 gold_assert(this->data_size() >= 24);
1694 unsigned char* const got_view = of->get_output_view(got_file_offset, 24);
1695 Output_section* dynamic = this->layout_->dynamic_section();
1696 uint64_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1697 elfcpp::Swap<64, false>::writeval(got_view, dynamic_addr);
1698 memset(got_view + 8, 0, 16);
1699 of->write_output_view(got_file_offset, 24, got_view);
1700 }
1701
1702 // Initialize the PLT section.
1703
1704 template<int size>
1705 void
1706 Output_data_plt_x86_64<size>::init(Layout* layout)
1707 {
1708 this->rel_ = new Reloc_section(false);
1709 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1710 elfcpp::SHF_ALLOC, this->rel_,
1711 ORDER_DYNAMIC_PLT_RELOCS, false);
1712 }
1713
1714 template<int size>
1715 void
1716 Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os)
1717 {
1718 os->set_entsize(this->get_plt_entry_size());
1719 }
1720
1721 // Add an entry to the PLT.
1722
1723 template<int size>
1724 void
1725 Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout,
1726 Symbol* gsym)
1727 {
1728 gold_assert(!gsym->has_plt_offset());
1729
1730 unsigned int plt_index;
1731 off_t plt_offset;
1732 section_offset_type got_offset;
1733
1734 unsigned int* pcount;
1735 unsigned int offset;
1736 unsigned int reserved;
1737 Output_section_data_build* got;
1738 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1739 && gsym->can_use_relative_reloc(false))
1740 {
1741 pcount = &this->irelative_count_;
1742 offset = 0;
1743 reserved = 0;
1744 got = this->got_irelative_;
1745 }
1746 else
1747 {
1748 pcount = &this->count_;
1749 offset = 1;
1750 reserved = 3;
1751 got = this->got_plt_;
1752 }
1753
1754 if (!this->is_data_size_valid())
1755 {
1756 // Note that when setting the PLT offset for a non-IRELATIVE
1757 // entry we skip the initial reserved PLT entry.
1758 plt_index = *pcount + offset;
1759 plt_offset = plt_index * this->get_plt_entry_size();
1760
1761 ++*pcount;
1762
1763 got_offset = (plt_index - offset + reserved) * 8;
1764 gold_assert(got_offset == got->current_data_size());
1765
1766 // Every PLT entry needs a GOT entry which points back to the PLT
1767 // entry (this will be changed by the dynamic linker, normally
1768 // lazily when the function is called).
1769 got->set_current_data_size(got_offset + 8);
1770 }
1771 else
1772 {
1773 // FIXME: This is probably not correct for IRELATIVE relocs.
1774
1775 // For incremental updates, find an available slot.
1776 plt_offset = this->free_list_.allocate(this->get_plt_entry_size(),
1777 this->get_plt_entry_size(), 0);
1778 if (plt_offset == -1)
1779 gold_fallback(_("out of patch space (PLT);"
1780 " relink with --incremental-full"));
1781
1782 // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset
1783 // can be calculated from the PLT index, adjusting for the three
1784 // reserved entries at the beginning of the GOT.
1785 plt_index = plt_offset / this->get_plt_entry_size() - 1;
1786 got_offset = (plt_index - offset + reserved) * 8;
1787 }
1788
1789 gsym->set_plt_offset(plt_offset);
1790
1791 // Every PLT entry needs a reloc.
1792 this->add_relocation(symtab, layout, gsym, got_offset);
1793
1794 // Note that we don't need to save the symbol. The contents of the
1795 // PLT are independent of which symbols are used. The symbols only
1796 // appear in the relocations.
1797 }
1798
1799 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1800 // the PLT offset.
1801
1802 template<int size>
1803 unsigned int
1804 Output_data_plt_x86_64<size>::add_local_ifunc_entry(
1805 Symbol_table* symtab,
1806 Layout* layout,
1807 Sized_relobj_file<size, false>* relobj,
1808 unsigned int local_sym_index)
1809 {
1810 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1811 ++this->irelative_count_;
1812
1813 section_offset_type got_offset = this->got_irelative_->current_data_size();
1814
1815 // Every PLT entry needs a GOT entry which points back to the PLT
1816 // entry.
1817 this->got_irelative_->set_current_data_size(got_offset + 8);
1818
1819 // Every PLT entry needs a reloc.
1820 Reloc_section* rela = this->rela_irelative(symtab, layout);
1821 rela->add_symbolless_local_addend(relobj, local_sym_index,
1822 elfcpp::R_X86_64_IRELATIVE,
1823 this->got_irelative_, got_offset, 0);
1824
1825 return plt_offset;
1826 }
1827
1828 // Add the relocation for a PLT entry.
1829
1830 template<int size>
1831 void
1832 Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab,
1833 Layout* layout,
1834 Symbol* gsym,
1835 unsigned int got_offset)
1836 {
1837 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1838 && gsym->can_use_relative_reloc(false))
1839 {
1840 Reloc_section* rela = this->rela_irelative(symtab, layout);
1841 rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
1842 this->got_irelative_, got_offset, 0);
1843 }
1844 else
1845 {
1846 gsym->set_needs_dynsym_entry();
1847 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
1848 got_offset, 0);
1849 }
1850 }
1851
1852 // Return where the TLSDESC relocations should go, creating it if
1853 // necessary. These follow the JUMP_SLOT relocations.
1854
1855 template<int size>
1856 typename Output_data_plt_x86_64<size>::Reloc_section*
1857 Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout)
1858 {
1859 if (this->tlsdesc_rel_ == NULL)
1860 {
1861 this->tlsdesc_rel_ = new Reloc_section(false);
1862 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1863 elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
1864 ORDER_DYNAMIC_PLT_RELOCS, false);
1865 gold_assert(this->tlsdesc_rel_->output_section()
1866 == this->rel_->output_section());
1867 }
1868 return this->tlsdesc_rel_;
1869 }
1870
1871 // Return where the IRELATIVE relocations should go in the PLT. These
1872 // follow the JUMP_SLOT and the TLSDESC relocations.
1873
1874 template<int size>
1875 typename Output_data_plt_x86_64<size>::Reloc_section*
1876 Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab,
1877 Layout* layout)
1878 {
1879 if (this->irelative_rel_ == NULL)
1880 {
1881 // Make sure we have a place for the TLSDESC relocations, in
1882 // case we see any later on.
1883 this->rela_tlsdesc(layout);
1884 this->irelative_rel_ = new Reloc_section(false);
1885 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1886 elfcpp::SHF_ALLOC, this->irelative_rel_,
1887 ORDER_DYNAMIC_PLT_RELOCS, false);
1888 gold_assert(this->irelative_rel_->output_section()
1889 == this->rel_->output_section());
1890
1891 if (parameters->doing_static_link())
1892 {
1893 // A statically linked executable will only have a .rela.plt
1894 // section to hold R_X86_64_IRELATIVE relocs for
1895 // STT_GNU_IFUNC symbols. The library will use these
1896 // symbols to locate the IRELATIVE relocs at program startup
1897 // time.
1898 symtab->define_in_output_data("__rela_iplt_start", NULL,
1899 Symbol_table::PREDEFINED,
1900 this->irelative_rel_, 0, 0,
1901 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1902 elfcpp::STV_HIDDEN, 0, false, true);
1903 symtab->define_in_output_data("__rela_iplt_end", NULL,
1904 Symbol_table::PREDEFINED,
1905 this->irelative_rel_, 0, 0,
1906 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1907 elfcpp::STV_HIDDEN, 0, true, true);
1908 }
1909 }
1910 return this->irelative_rel_;
1911 }
1912
1913 // Return the PLT address to use for a global symbol.
1914
1915 template<int size>
1916 uint64_t
1917 Output_data_plt_x86_64<size>::do_address_for_global(const Symbol* gsym)
1918 {
1919 uint64_t offset = 0;
1920 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1921 && gsym->can_use_relative_reloc(false))
1922 offset = (this->count_ + 1) * this->get_plt_entry_size();
1923 return this->address() + offset + gsym->plt_offset();
1924 }
1925
1926 // Return the PLT address to use for a local symbol. These are always
1927 // IRELATIVE relocs.
1928
1929 template<int size>
1930 uint64_t
1931 Output_data_plt_x86_64<size>::do_address_for_local(const Relobj* object,
1932 unsigned int r_sym)
1933 {
1934 return (this->address()
1935 + (this->count_ + 1) * this->get_plt_entry_size()
1936 + object->local_plt_offset(r_sym));
1937 }
1938
1939 // Set the final size.
1940 template<int size>
1941 void
1942 Output_data_plt_x86_64<size>::set_final_data_size()
1943 {
1944 // Number of regular and IFUNC PLT entries, plus the first entry.
1945 unsigned int count = this->count_ + this->irelative_count_ + 1;
1946 // Count the TLSDESC entry, if present.
1947 if (this->has_tlsdesc_entry())
1948 ++count;
1949 this->set_data_size(count * this->get_plt_entry_size());
1950 }
1951
1952 // The first entry in the PLT for an executable.
1953
1954 template<int size>
1955 const unsigned char
1956 Output_data_plt_x86_64_standard<size>::first_plt_entry[plt_entry_size] =
1957 {
1958 // From AMD64 ABI Draft 0.98, page 76
1959 0xff, 0x35, // pushq contents of memory address
1960 0, 0, 0, 0, // replaced with address of .got + 8
1961 0xff, 0x25, // jmp indirect
1962 0, 0, 0, 0, // replaced with address of .got + 16
1963 0x90, 0x90, 0x90, 0x90 // noop (x4)
1964 };
1965
1966 template<int size>
1967 void
1968 Output_data_plt_x86_64_standard<size>::do_fill_first_plt_entry(
1969 unsigned char* pov,
1970 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
1971 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
1972 {
1973 memcpy(pov, first_plt_entry, plt_entry_size);
1974 // We do a jmp relative to the PC at the end of this instruction.
1975 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1976 (got_address + 8
1977 - (plt_address + 6)));
1978 elfcpp::Swap<32, false>::writeval(pov + 8,
1979 (got_address + 16
1980 - (plt_address + 12)));
1981 }
1982
1983 // Subsequent entries in the PLT for an executable.
1984
1985 template<int size>
1986 const unsigned char
1987 Output_data_plt_x86_64_standard<size>::plt_entry[plt_entry_size] =
1988 {
1989 // From AMD64 ABI Draft 0.98, page 76
1990 0xff, 0x25, // jmpq indirect
1991 0, 0, 0, 0, // replaced with address of symbol in .got
1992 0x68, // pushq immediate
1993 0, 0, 0, 0, // replaced with offset into relocation table
1994 0xe9, // jmpq relative
1995 0, 0, 0, 0 // replaced with offset to start of .plt
1996 };
1997
1998 template<int size>
1999 unsigned int
2000 Output_data_plt_x86_64_standard<size>::do_fill_plt_entry(
2001 unsigned char* pov,
2002 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
2003 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
2004 unsigned int got_offset,
2005 unsigned int plt_offset,
2006 unsigned int plt_index)
2007 {
2008 // Check PC-relative offset overflow in PLT entry.
2009 uint64_t plt_got_pcrel_offset = (got_address + got_offset
2010 - (plt_address + plt_offset + 6));
2011 if (Bits<32>::has_overflow(plt_got_pcrel_offset))
2012 gold_error(_("PC-relative offset overflow in PLT entry %d"),
2013 plt_index + 1);
2014
2015 memcpy(pov, plt_entry, plt_entry_size);
2016 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
2017 plt_got_pcrel_offset);
2018
2019 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
2020 elfcpp::Swap<32, false>::writeval(pov + 12,
2021 - (plt_offset + plt_entry_size));
2022
2023 return 6;
2024 }
2025
2026 // The reserved TLSDESC entry in the PLT for an executable.
2027
2028 template<int size>
2029 const unsigned char
2030 Output_data_plt_x86_64_standard<size>::tlsdesc_plt_entry[plt_entry_size] =
2031 {
2032 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
2033 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
2034 0xff, 0x35, // pushq x(%rip)
2035 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
2036 0xff, 0x25, // jmpq *y(%rip)
2037 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
2038 0x0f, 0x1f, // nop
2039 0x40, 0
2040 };
2041
2042 template<int size>
2043 void
2044 Output_data_plt_x86_64_standard<size>::do_fill_tlsdesc_entry(
2045 unsigned char* pov,
2046 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
2047 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
2048 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
2049 unsigned int tlsdesc_got_offset,
2050 unsigned int plt_offset)
2051 {
2052 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
2053 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
2054 (got_address + 8
2055 - (plt_address + plt_offset
2056 + 6)));
2057 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
2058 (got_base
2059 + tlsdesc_got_offset
2060 - (plt_address + plt_offset
2061 + 12)));
2062 }
2063
2064 // Return the APLT address to use for a global symbol (for -z bndplt).
2065
2066 uint64_t
2067 Output_data_plt_x86_64_bnd::do_address_for_global(const Symbol* gsym)
2068 {
2069 uint64_t offset = this->aplt_offset_;
2070 // Convert the PLT offset into an APLT offset.
2071 unsigned int plt_offset = gsym->plt_offset();
2072 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2073 && gsym->can_use_relative_reloc(false))
2074 offset += this->regular_count() * aplt_entry_size;
2075 else
2076 plt_offset -= plt_entry_size;
2077 plt_offset = plt_offset / (plt_entry_size / aplt_entry_size);
2078 return this->address() + offset + plt_offset;
2079 }
2080
2081 // Return the PLT address to use for a local symbol. These are always
2082 // IRELATIVE relocs.
2083
2084 uint64_t
2085 Output_data_plt_x86_64_bnd::do_address_for_local(const Relobj* object,
2086 unsigned int r_sym)
2087 {
2088 // Convert the PLT offset into an APLT offset.
2089 const Sized_relobj_file<64, false>* sized_relobj =
2090 static_cast<const Sized_relobj_file<64, false>*>(object);
2091 const Symbol_value<64>* psymval = sized_relobj->local_symbol(r_sym);
2092 unsigned int plt_offset = ((object->local_plt_offset(r_sym)
2093 - (psymval->is_ifunc_symbol()
2094 ? 0 : plt_entry_size))
2095 / (plt_entry_size / aplt_entry_size));
2096 return (this->address()
2097 + this->aplt_offset_
2098 + this->regular_count() * aplt_entry_size
2099 + plt_offset);
2100 }
2101
2102 // Set the final size.
2103 void
2104 Output_data_plt_x86_64_bnd::set_final_data_size()
2105 {
2106 // Number of regular and IFUNC PLT entries.
2107 unsigned int count = this->entry_count();
2108 // Count the first entry and the TLSDESC entry, if present.
2109 unsigned int extra = this->has_tlsdesc_entry() ? 2 : 1;
2110 unsigned int plt_size = (count + extra) * plt_entry_size;
2111 // Offset of the APLT.
2112 this->aplt_offset_ = plt_size;
2113 // Size of the APLT.
2114 plt_size += count * aplt_entry_size;
2115 this->set_data_size(plt_size);
2116 }
2117
2118 // The first entry in the BND PLT.
2119
2120 const unsigned char
2121 Output_data_plt_x86_64_bnd::first_plt_entry[plt_entry_size] =
2122 {
2123 // From AMD64 ABI Draft 0.98, page 76
2124 0xff, 0x35, // pushq contents of memory address
2125 0, 0, 0, 0, // replaced with address of .got + 8
2126 0xf2, 0xff, 0x25, // bnd jmp indirect
2127 0, 0, 0, 0, // replaced with address of .got + 16
2128 0x0f, 0x1f, 0x00 // nop
2129 };
2130
2131 void
2132 Output_data_plt_x86_64_bnd::do_fill_first_plt_entry(
2133 unsigned char* pov,
2134 elfcpp::Elf_types<64>::Elf_Addr got_address,
2135 elfcpp::Elf_types<64>::Elf_Addr plt_address)
2136 {
2137 memcpy(pov, first_plt_entry, plt_entry_size);
2138 // We do a jmp relative to the PC at the end of this instruction.
2139 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
2140 (got_address + 8
2141 - (plt_address + 6)));
2142 elfcpp::Swap<32, false>::writeval(pov + 9,
2143 (got_address + 16
2144 - (plt_address + 13)));
2145 }
2146
2147 // Subsequent entries in the BND PLT.
2148
2149 const unsigned char
2150 Output_data_plt_x86_64_bnd::plt_entry[plt_entry_size] =
2151 {
2152 // From AMD64 ABI Draft 0.99.8, page 139
2153 0x68, // pushq immediate
2154 0, 0, 0, 0, // replaced with offset into relocation table
2155 0xf2, 0xe9, // bnd jmpq relative
2156 0, 0, 0, 0, // replaced with offset to start of .plt
2157 0x0f, 0x1f, 0x44, 0, 0 // nop
2158 };
2159
2160 // Entries in the BND Additional PLT.
2161
2162 const unsigned char
2163 Output_data_plt_x86_64_bnd::aplt_entry[aplt_entry_size] =
2164 {
2165 // From AMD64 ABI Draft 0.99.8, page 139
2166 0xf2, 0xff, 0x25, // bnd jmpq indirect
2167 0, 0, 0, 0, // replaced with address of symbol in .got
2168 0x90, // nop
2169 };
2170
2171 unsigned int
2172 Output_data_plt_x86_64_bnd::do_fill_plt_entry(
2173 unsigned char* pov,
2174 elfcpp::Elf_types<64>::Elf_Addr,
2175 elfcpp::Elf_types<64>::Elf_Addr,
2176 unsigned int,
2177 unsigned int plt_offset,
2178 unsigned int plt_index)
2179 {
2180 memcpy(pov, plt_entry, plt_entry_size);
2181 elfcpp::Swap_unaligned<32, false>::writeval(pov + 1, plt_index);
2182 elfcpp::Swap<32, false>::writeval(pov + 7, -(plt_offset + 11));
2183 return 0;
2184 }
2185
2186 void
2187 Output_data_plt_x86_64_bnd::fill_aplt_entry(
2188 unsigned char* pov,
2189 elfcpp::Elf_types<64>::Elf_Addr got_address,
2190 elfcpp::Elf_types<64>::Elf_Addr plt_address,
2191 unsigned int got_offset,
2192 unsigned int plt_offset,
2193 unsigned int plt_index)
2194 {
2195 // Check PC-relative offset overflow in PLT entry.
2196 uint64_t plt_got_pcrel_offset = (got_address + got_offset
2197 - (plt_address + plt_offset + 7));
2198 if (Bits<32>::has_overflow(plt_got_pcrel_offset))
2199 gold_error(_("PC-relative offset overflow in APLT entry %d"),
2200 plt_index + 1);
2201
2202 memcpy(pov, aplt_entry, aplt_entry_size);
2203 elfcpp::Swap_unaligned<32, false>::writeval(pov + 3, plt_got_pcrel_offset);
2204 }
2205
2206 // The reserved TLSDESC entry in the PLT for an executable.
2207
2208 const unsigned char
2209 Output_data_plt_x86_64_bnd::tlsdesc_plt_entry[plt_entry_size] =
2210 {
2211 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
2212 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
2213 0xff, 0x35, // pushq x(%rip)
2214 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
2215 0xf2, 0xff, 0x25, // jmpq *y(%rip)
2216 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
2217 0x0f, 0x1f, 0 // nop
2218 };
2219
2220 void
2221 Output_data_plt_x86_64_bnd::do_fill_tlsdesc_entry(
2222 unsigned char* pov,
2223 elfcpp::Elf_types<64>::Elf_Addr got_address,
2224 elfcpp::Elf_types<64>::Elf_Addr plt_address,
2225 elfcpp::Elf_types<64>::Elf_Addr got_base,
2226 unsigned int tlsdesc_got_offset,
2227 unsigned int plt_offset)
2228 {
2229 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
2230 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
2231 (got_address + 8
2232 - (plt_address + plt_offset
2233 + 6)));
2234 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
2235 (got_base
2236 + tlsdesc_got_offset
2237 - (plt_address + plt_offset
2238 + 13)));
2239 }
2240
2241 // Return the APLT address to use for a global symbol (for IBT).
2242
2243 template<int size>
2244 uint64_t
2245 Output_data_plt_x86_64_ibt<size>::do_address_for_global(const Symbol* gsym)
2246 {
2247 uint64_t offset = this->aplt_offset_;
2248 // Convert the PLT offset into an APLT offset.
2249 unsigned int plt_offset = gsym->plt_offset();
2250 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2251 && gsym->can_use_relative_reloc(false))
2252 offset += this->regular_count() * aplt_entry_size;
2253 else
2254 plt_offset -= plt_entry_size;
2255 plt_offset = plt_offset / (plt_entry_size / aplt_entry_size);
2256 return this->address() + offset + plt_offset;
2257 }
2258
2259 // Return the PLT address to use for a local symbol. These are always
2260 // IRELATIVE relocs.
2261
2262 template<int size>
2263 uint64_t
2264 Output_data_plt_x86_64_ibt<size>::do_address_for_local(const Relobj* object,
2265 unsigned int r_sym)
2266 {
2267 // Convert the PLT offset into an APLT offset.
2268 const Sized_relobj_file<size, false>* sized_relobj =
2269 static_cast<const Sized_relobj_file<size, false>*>(object);
2270 const Symbol_value<size>* psymval = sized_relobj->local_symbol(r_sym);
2271 unsigned int plt_offset = ((object->local_plt_offset(r_sym)
2272 - (psymval->is_ifunc_symbol()
2273 ? 0 : plt_entry_size))
2274 / (plt_entry_size / aplt_entry_size));
2275 return (this->address()
2276 + this->aplt_offset_
2277 + this->regular_count() * aplt_entry_size
2278 + plt_offset);
2279 }
2280
2281 // Set the final size.
2282
2283 template<int size>
2284 void
2285 Output_data_plt_x86_64_ibt<size>::set_final_data_size()
2286 {
2287 // Number of regular and IFUNC PLT entries.
2288 unsigned int count = this->entry_count();
2289 // Count the first entry and the TLSDESC entry, if present.
2290 unsigned int extra = this->has_tlsdesc_entry() ? 2 : 1;
2291 unsigned int plt_size = (count + extra) * plt_entry_size;
2292 // Offset of the APLT.
2293 this->aplt_offset_ = plt_size;
2294 // Size of the APLT.
2295 plt_size += count * aplt_entry_size;
2296 this->set_data_size(plt_size);
2297 }
2298
2299 // The first entry in the IBT PLT.
2300
2301 template<>
2302 const unsigned char
2303 Output_data_plt_x86_64_ibt<32>::first_plt_entry[plt_entry_size] =
2304 {
2305 // MPX isn't supported for x32, so we don't need the BND prefix.
2306 // From AMD64 ABI Draft 0.98, page 76
2307 0xff, 0x35, // pushq contents of memory address
2308 0, 0, 0, 0, // replaced with address of .got + 8
2309 0xff, 0x25, // jmp indirect
2310 0, 0, 0, 0, // replaced with address of .got + 16
2311 0x90, 0x90, 0x90, 0x90 // noop (x4)
2312 };
2313
2314 template<>
2315 const unsigned char
2316 Output_data_plt_x86_64_ibt<64>::first_plt_entry[plt_entry_size] =
2317 {
2318 // Use the BND prefix so that IBT is compatible with MPX.
2319 0xff, 0x35, // pushq contents of memory address
2320 0, 0, 0, 0, // replaced with address of .got + 8
2321 0xf2, 0xff, 0x25, // bnd jmp indirect
2322 0, 0, 0, 0, // replaced with address of .got + 16
2323 0x0f, 0x1f, 0x00 // nop
2324 };
2325
2326 template<int size>
2327 void
2328 Output_data_plt_x86_64_ibt<size>::do_fill_first_plt_entry(
2329 unsigned char* pov,
2330 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
2331 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
2332 {
2333 // Offsets to the addresses needing relocation.
2334 const unsigned int roff1 = 2;
2335 const unsigned int roff2 = (size == 32) ? 8 : 9;
2336
2337 memcpy(pov, first_plt_entry, plt_entry_size);
2338 // We do a jmp relative to the PC at the end of this instruction.
2339 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1,
2340 (got_address + 8
2341 - (plt_address + roff1 + 4)));
2342 elfcpp::Swap<32, false>::writeval(pov + roff2,
2343 (got_address + 16
2344 - (plt_address + roff2 + 4)));
2345 }
2346
2347 // Subsequent entries in the IBT PLT.
2348
2349 template<>
2350 const unsigned char
2351 Output_data_plt_x86_64_ibt<32>::plt_entry[plt_entry_size] =
2352 {
2353 // From AMD64 ABI Draft 1.0-rc1, Chapter 13.
2354 0xf3, 0x0f, 0x1e, 0xfa, // endbr64
2355 0x68, // pushq immediate
2356 0, 0, 0, 0, // replaced with offset into relocation table
2357 0xe9, // jmpq relative
2358 0, 0, 0, 0, // replaced with offset to start of .plt
2359 0x90, 0x90 // nop
2360 };
2361
2362 template<>
2363 const unsigned char
2364 Output_data_plt_x86_64_ibt<64>::plt_entry[plt_entry_size] =
2365 {
2366 // From AMD64 ABI Draft 1.0-rc1, Chapter 13.
2367 0xf3, 0x0f, 0x1e, 0xfa, // endbr64
2368 0x68, // pushq immediate
2369 0, 0, 0, 0, // replaced with offset into relocation table
2370 0xf2, 0xe9, // bnd jmpq relative
2371 0, 0, 0, 0, // replaced with offset to start of .plt
2372 0x90 // nop
2373 };
2374
2375 // Entries in the IBT Additional PLT.
2376
2377 template<>
2378 const unsigned char
2379 Output_data_plt_x86_64_ibt<32>::aplt_entry[aplt_entry_size] =
2380 {
2381 // From AMD64 ABI Draft 1.0-rc1, Chapter 13.
2382 0xf3, 0x0f, 0x1e, 0xfa, // endbr64
2383 0xff, 0x25, // jmpq indirect
2384 0, 0, 0, 0, // replaced with address of symbol in .got
2385 0x0f, 0x1f, 0x04, 0x00, // nop
2386 0x90, 0x90 // nop
2387 };
2388
2389 template<>
2390 const unsigned char
2391 Output_data_plt_x86_64_ibt<64>::aplt_entry[aplt_entry_size] =
2392 {
2393 // From AMD64 ABI Draft 1.0-rc1, Chapter 13.
2394 0xf3, 0x0f, 0x1e, 0xfa, // endbr64
2395 0xf2, 0xff, 0x25, // bnd jmpq indirect
2396 0, 0, 0, 0, // replaced with address of symbol in .got
2397 0x0f, 0x1f, 0x04, 0x00, // nop
2398 0x90, // nop
2399 };
2400
2401 template<int size>
2402 unsigned int
2403 Output_data_plt_x86_64_ibt<size>::do_fill_plt_entry(
2404 unsigned char* pov,
2405 typename elfcpp::Elf_types<size>::Elf_Addr,
2406 typename elfcpp::Elf_types<size>::Elf_Addr,
2407 unsigned int,
2408 unsigned int plt_offset,
2409 unsigned int plt_index)
2410 {
2411 // Offsets to the addresses needing relocation.
2412 const unsigned int roff1 = 5;
2413 const unsigned int roff2 = (size == 32) ? 10 : 11;
2414
2415 memcpy(pov, plt_entry, plt_entry_size);
2416 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1, plt_index);
2417 elfcpp::Swap<32, false>::writeval(pov + roff2, -(plt_offset + roff2 + 4));
2418 return 0;
2419 }
2420
2421 template<int size>
2422 void
2423 Output_data_plt_x86_64_ibt<size>::fill_aplt_entry(
2424 unsigned char* pov,
2425 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
2426 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
2427 unsigned int got_offset,
2428 unsigned int plt_offset,
2429 unsigned int plt_index)
2430 {
2431 // Offset to the address needing relocation.
2432 const unsigned int roff = (size == 32) ? 6 : 7;
2433
2434 // Check PC-relative offset overflow in PLT entry.
2435 uint64_t plt_got_pcrel_offset = (got_address + got_offset
2436 - (plt_address + plt_offset + roff + 4));
2437 if (Bits<32>::has_overflow(plt_got_pcrel_offset))
2438 gold_error(_("PC-relative offset overflow in APLT entry %d"),
2439 plt_index + 1);
2440
2441 memcpy(pov, aplt_entry, aplt_entry_size);
2442 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff, plt_got_pcrel_offset);
2443 }
2444
2445 // The reserved TLSDESC entry in the IBT PLT for an executable.
2446
2447 template<int size>
2448 const unsigned char
2449 Output_data_plt_x86_64_ibt<size>::tlsdesc_plt_entry[plt_entry_size] =
2450 {
2451 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
2452 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
2453 0xff, 0x35, // pushq x(%rip)
2454 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
2455 0xf2, 0xff, 0x25, // jmpq *y(%rip)
2456 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
2457 0x0f, 0x1f, 0 // nop
2458 };
2459
2460 template<int size>
2461 void
2462 Output_data_plt_x86_64_ibt<size>::do_fill_tlsdesc_entry(
2463 unsigned char* pov,
2464 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
2465 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
2466 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
2467 unsigned int tlsdesc_got_offset,
2468 unsigned int plt_offset)
2469 {
2470 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
2471 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
2472 (got_address + 8
2473 - (plt_address + plt_offset
2474 + 6)));
2475 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
2476 (got_base
2477 + tlsdesc_got_offset
2478 - (plt_address + plt_offset
2479 + 13)));
2480 }
2481
2482 // The .eh_frame unwind information for the PLT.
2483
2484 template<int size>
2485 const unsigned char
2486 Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] =
2487 {
2488 1, // CIE version.
2489 'z', // Augmentation: augmentation size included.
2490 'R', // Augmentation: FDE encoding included.
2491 '\0', // End of augmentation string.
2492 1, // Code alignment factor.
2493 0x78, // Data alignment factor.
2494 16, // Return address column.
2495 1, // Augmentation size.
2496 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
2497 | elfcpp::DW_EH_PE_sdata4),
2498 elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8.
2499 elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8.
2500 elfcpp::DW_CFA_nop, // Align to 16 bytes.
2501 elfcpp::DW_CFA_nop
2502 };
2503
2504 template<int size>
2505 const unsigned char
2506 Output_data_plt_x86_64_standard<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
2507 {
2508 0, 0, 0, 0, // Replaced with offset to .plt.
2509 0, 0, 0, 0, // Replaced with size of .plt.
2510 0, // Augmentation size.
2511 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
2512 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
2513 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
2514 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
2515 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
2516 11, // Block length.
2517 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
2518 elfcpp::DW_OP_breg16, 0, // Push %rip.
2519 elfcpp::DW_OP_lit15, // Push 0xf.
2520 elfcpp::DW_OP_and, // & (%rip & 0xf).
2521 elfcpp::DW_OP_lit11, // Push 0xb.
2522 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb)
2523 elfcpp::DW_OP_lit3, // Push 3.
2524 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3)
2525 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8
2526 elfcpp::DW_CFA_nop, // Align to 32 bytes.
2527 elfcpp::DW_CFA_nop,
2528 elfcpp::DW_CFA_nop,
2529 elfcpp::DW_CFA_nop
2530 };
2531
2532 // The .eh_frame unwind information for the BND PLT.
2533 const unsigned char
2534 Output_data_plt_x86_64_bnd::plt_eh_frame_fde[plt_eh_frame_fde_size] =
2535 {
2536 0, 0, 0, 0, // Replaced with offset to .plt.
2537 0, 0, 0, 0, // Replaced with size of .plt.
2538 0, // Augmentation size.
2539 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
2540 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
2541 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
2542 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
2543 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
2544 11, // Block length.
2545 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
2546 elfcpp::DW_OP_breg16, 0, // Push %rip.
2547 elfcpp::DW_OP_lit15, // Push 0xf.
2548 elfcpp::DW_OP_and, // & (%rip & 0xf).
2549 elfcpp::DW_OP_lit5, // Push 5.
2550 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 5)
2551 elfcpp::DW_OP_lit3, // Push 3.
2552 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 5) << 3)
2553 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=5)<<3)+%rsp+8
2554 elfcpp::DW_CFA_nop, // Align to 32 bytes.
2555 elfcpp::DW_CFA_nop,
2556 elfcpp::DW_CFA_nop,
2557 elfcpp::DW_CFA_nop
2558 };
2559
2560 // The .eh_frame unwind information for the BND PLT.
2561 template<int size>
2562 const unsigned char
2563 Output_data_plt_x86_64_ibt<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
2564 {
2565 0, 0, 0, 0, // Replaced with offset to .plt.
2566 0, 0, 0, 0, // Replaced with size of .plt.
2567 0, // Augmentation size.
2568 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
2569 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
2570 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
2571 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
2572 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
2573 11, // Block length.
2574 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
2575 elfcpp::DW_OP_breg16, 0, // Push %rip.
2576 elfcpp::DW_OP_lit15, // Push 0xf.
2577 elfcpp::DW_OP_and, // & (%rip & 0xf).
2578 elfcpp::DW_OP_lit9, // Push 9.
2579 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 9)
2580 elfcpp::DW_OP_lit3, // Push 3.
2581 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 9) << 3)
2582 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=9)<<3)+%rsp+8
2583 elfcpp::DW_CFA_nop, // Align to 32 bytes.
2584 elfcpp::DW_CFA_nop,
2585 elfcpp::DW_CFA_nop,
2586 elfcpp::DW_CFA_nop
2587 };
2588
2589 // Write out the PLT. This uses the hand-coded instructions above,
2590 // and adjusts them as needed. This is specified by the AMD64 ABI.
2591
2592 template<int size>
2593 void
2594 Output_data_plt_x86_64<size>::do_write(Output_file* of)
2595 {
2596 const off_t offset = this->offset();
2597 const section_size_type oview_size =
2598 convert_to_section_size_type(this->data_size());
2599 unsigned char* const oview = of->get_output_view(offset, oview_size);
2600
2601 const off_t got_file_offset = this->got_plt_->offset();
2602 gold_assert(parameters->incremental_update()
2603 || (got_file_offset + this->got_plt_->data_size()
2604 == this->got_irelative_->offset()));
2605 const section_size_type got_size =
2606 convert_to_section_size_type(this->got_plt_->data_size()
2607 + this->got_irelative_->data_size());
2608 unsigned char* const got_view = of->get_output_view(got_file_offset,
2609 got_size);
2610
2611 unsigned char* pov = oview;
2612
2613 // The base address of the .plt section.
2614 typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address();
2615 // The base address of the .got section.
2616 typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address();
2617 // The base address of the PLT portion of the .got section,
2618 // which is where the GOT pointer will point, and where the
2619 // three reserved GOT entries are located.
2620 typename elfcpp::Elf_types<size>::Elf_Addr got_address
2621 = this->got_plt_->address();
2622
2623 this->fill_first_plt_entry(pov, got_address, plt_address);
2624 pov += this->get_plt_entry_size();
2625
2626 // The first three entries in the GOT are reserved, and are written
2627 // by Output_data_got_plt_x86_64::do_write.
2628 unsigned char* got_pov = got_view + 24;
2629
2630 unsigned int plt_offset = this->get_plt_entry_size();
2631 unsigned int got_offset = 24;
2632 const unsigned int count = this->count_ + this->irelative_count_;
2633 for (unsigned int plt_index = 0;
2634 plt_index < count;
2635 ++plt_index,
2636 pov += this->get_plt_entry_size(),
2637 got_pov += 8,
2638 plt_offset += this->get_plt_entry_size(),
2639 got_offset += 8)
2640 {
2641 // Set and adjust the PLT entry itself.
2642 unsigned int lazy_offset = this->fill_plt_entry(pov,
2643 got_address, plt_address,
2644 got_offset, plt_offset,
2645 plt_index);
2646
2647 // Set the entry in the GOT.
2648 elfcpp::Swap<64, false>::writeval(got_pov,
2649 plt_address + plt_offset + lazy_offset);
2650 }
2651
2652 if (this->has_tlsdesc_entry())
2653 {
2654 // Set and adjust the reserved TLSDESC PLT entry.
2655 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
2656 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
2657 tlsdesc_got_offset, plt_offset);
2658 pov += this->get_plt_entry_size();
2659 }
2660
2661 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
2662 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
2663
2664 of->write_output_view(offset, oview_size, oview);
2665 of->write_output_view(got_file_offset, got_size, got_view);
2666 }
2667
2668 // Write out the BND PLT.
2669
2670 void
2671 Output_data_plt_x86_64_bnd::do_write(Output_file* of)
2672 {
2673 const off_t offset = this->offset();
2674 const section_size_type oview_size =
2675 convert_to_section_size_type(this->data_size());
2676 unsigned char* const oview = of->get_output_view(offset, oview_size);
2677
2678 Output_data_got<64, false>* got = this->got();
2679 Output_data_got_plt_x86_64* got_plt = this->got_plt();
2680 Output_data_space* got_irelative = this->got_irelative();
2681
2682 const off_t got_file_offset = got_plt->offset();
2683 gold_assert(parameters->incremental_update()
2684 || (got_file_offset + got_plt->data_size()
2685 == got_irelative->offset()));
2686 const section_size_type got_size =
2687 convert_to_section_size_type(got_plt->data_size()
2688 + got_irelative->data_size());
2689 unsigned char* const got_view = of->get_output_view(got_file_offset,
2690 got_size);
2691
2692 unsigned char* pov = oview;
2693
2694 // The base address of the .plt section.
2695 elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
2696 // The base address of the .got section.
2697 elfcpp::Elf_types<64>::Elf_Addr got_base = got->address();
2698 // The base address of the PLT portion of the .got section,
2699 // which is where the GOT pointer will point, and where the
2700 // three reserved GOT entries are located.
2701 elfcpp::Elf_types<64>::Elf_Addr got_address = got_plt->address();
2702
2703 this->fill_first_plt_entry(pov, got_address, plt_address);
2704 pov += plt_entry_size;
2705
2706 // The first three entries in the GOT are reserved, and are written
2707 // by Output_data_got_plt_x86_64::do_write.
2708 unsigned char* got_pov = got_view + 24;
2709
2710 unsigned int plt_offset = plt_entry_size;
2711 unsigned int got_offset = 24;
2712 const unsigned int count = this->entry_count();
2713 for (unsigned int plt_index = 0;
2714 plt_index < count;
2715 ++plt_index,
2716 pov += plt_entry_size,
2717 got_pov += 8,
2718 plt_offset += plt_entry_size,
2719 got_offset += 8)
2720 {
2721 // Set and adjust the PLT entry itself.
2722 unsigned int lazy_offset = this->fill_plt_entry(pov,
2723 got_address, plt_address,
2724 got_offset, plt_offset,
2725 plt_index);
2726
2727 // Set the entry in the GOT.
2728 elfcpp::Swap<64, false>::writeval(got_pov,
2729 plt_address + plt_offset + lazy_offset);
2730 }
2731
2732 if (this->has_tlsdesc_entry())
2733 {
2734 // Set and adjust the reserved TLSDESC PLT entry.
2735 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
2736 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
2737 tlsdesc_got_offset, plt_offset);
2738 pov += this->get_plt_entry_size();
2739 plt_offset += plt_entry_size;
2740 }
2741
2742 // Write the additional PLT.
2743 got_offset = 24;
2744 for (unsigned int plt_index = 0;
2745 plt_index < count;
2746 ++plt_index,
2747 pov += aplt_entry_size,
2748 plt_offset += aplt_entry_size,
2749 got_offset += 8)
2750 {
2751 // Set and adjust the APLT entry.
2752 this->fill_aplt_entry(pov, got_address, plt_address, got_offset,
2753 plt_offset, plt_index);
2754 }
2755
2756 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
2757 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
2758
2759 of->write_output_view(offset, oview_size, oview);
2760 of->write_output_view(got_file_offset, got_size, got_view);
2761 }
2762
2763 // Write out the IBT PLT.
2764
2765 template<int size>
2766 void
2767 Output_data_plt_x86_64_ibt<size>::do_write(Output_file* of)
2768 {
2769 const off_t offset = this->offset();
2770 const section_size_type oview_size =
2771 convert_to_section_size_type(this->data_size());
2772 unsigned char* const oview = of->get_output_view(offset, oview_size);
2773
2774 Output_data_got<64, false>* got = this->got();
2775 Output_data_got_plt_x86_64* got_plt = this->got_plt();
2776 Output_data_space* got_irelative = this->got_irelative();
2777
2778 const off_t got_file_offset = got_plt->offset();
2779 gold_assert(parameters->incremental_update()
2780 || (got_file_offset + got_plt->data_size()
2781 == got_irelative->offset()));
2782 const section_size_type got_size =
2783 convert_to_section_size_type(got_plt->data_size()
2784 + got_irelative->data_size());
2785 unsigned char* const got_view = of->get_output_view(got_file_offset,
2786 got_size);
2787
2788 unsigned char* pov = oview;
2789
2790 // The base address of the .plt section.
2791 elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
2792 // The base address of the .got section.
2793 elfcpp::Elf_types<64>::Elf_Addr got_base = got->address();
2794 // The base address of the PLT portion of the .got section,
2795 // which is where the GOT pointer will point, and where the
2796 // three reserved GOT entries are located.
2797 elfcpp::Elf_types<64>::Elf_Addr got_address = got_plt->address();
2798
2799 this->fill_first_plt_entry(pov, got_address, plt_address);
2800 pov += plt_entry_size;
2801
2802 // The first three entries in the GOT are reserved, and are written
2803 // by Output_data_got_plt_x86_64::do_write.
2804 unsigned char* got_pov = got_view + 24;
2805
2806 unsigned int plt_offset = plt_entry_size;
2807 unsigned int got_offset = 24;
2808 const unsigned int count = this->entry_count();
2809 for (unsigned int plt_index = 0;
2810 plt_index < count;
2811 ++plt_index,
2812 pov += plt_entry_size,
2813 got_pov += 8,
2814 plt_offset += plt_entry_size,
2815 got_offset += 8)
2816 {
2817 // Set and adjust the PLT entry itself.
2818 unsigned int lazy_offset = this->fill_plt_entry(pov,
2819 got_address, plt_address,
2820 got_offset, plt_offset,
2821 plt_index);
2822
2823 // Set the entry in the GOT.
2824 elfcpp::Swap<64, false>::writeval(got_pov,
2825 plt_address + plt_offset + lazy_offset);
2826 }
2827
2828 if (this->has_tlsdesc_entry())
2829 {
2830 // Set and adjust the reserved TLSDESC PLT entry.
2831 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
2832 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base,
2833 tlsdesc_got_offset, plt_offset);
2834 pov += this->get_plt_entry_size();
2835 plt_offset += plt_entry_size;
2836 }
2837
2838 // Write the additional PLT.
2839 got_offset = 24;
2840 for (unsigned int plt_index = 0;
2841 plt_index < count;
2842 ++plt_index,
2843 pov += aplt_entry_size,
2844 plt_offset += aplt_entry_size,
2845 got_offset += 8)
2846 {
2847 // Set and adjust the APLT entry.
2848 this->fill_aplt_entry(pov, got_address, plt_address, got_offset,
2849 plt_offset, plt_index);
2850 }
2851
2852 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
2853 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
2854
2855 of->write_output_view(offset, oview_size, oview);
2856 of->write_output_view(got_file_offset, got_size, got_view);
2857 }
2858
2859 // Create the PLT section.
2860
2861 template<int size>
2862 void
2863 Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout)
2864 {
2865 if (this->plt_ == NULL)
2866 {
2867 // Create the GOT sections first.
2868 this->got_section(symtab, layout);
2869
2870 this->plt_ = this->make_data_plt(layout, this->got_, this->got_plt_,
2871 this->got_irelative_);
2872
2873 // Add unwind information if requested.
2874 if (parameters->options().ld_generated_unwind_info())
2875 this->plt_->add_eh_frame(layout);
2876
2877 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
2878 (elfcpp::SHF_ALLOC
2879 | elfcpp::SHF_EXECINSTR),
2880 this->plt_, ORDER_PLT, false);
2881
2882 // Make the sh_info field of .rela.plt point to .plt.
2883 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
2884 rela_plt_os->set_info_section(this->plt_->output_section());
2885 }
2886 }
2887
2888 template<>
2889 Output_data_plt_x86_64<32>*
2890 Target_x86_64<32>::do_make_data_plt(Layout* layout,
2891 Output_data_got<64, false>* got,
2892 Output_data_got_plt_x86_64* got_plt,
2893 Output_data_space* got_irelative)
2894 {
2895 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT)
2896 return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt,
2897 got_irelative);
2898 return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt,
2899 got_irelative);
2900 }
2901
2902 template<>
2903 Output_data_plt_x86_64<64>*
2904 Target_x86_64<64>::do_make_data_plt(Layout* layout,
2905 Output_data_got<64, false>* got,
2906 Output_data_got_plt_x86_64* got_plt,
2907 Output_data_space* got_irelative)
2908 {
2909 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT)
2910 return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt,
2911 got_irelative);
2912 else if (parameters->options().bndplt())
2913 return new Output_data_plt_x86_64_bnd(layout, got, got_plt,
2914 got_irelative);
2915 else
2916 return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt,
2917 got_irelative);
2918 }
2919
2920 template<>
2921 Output_data_plt_x86_64<32>*
2922 Target_x86_64<32>::do_make_data_plt(Layout* layout,
2923 Output_data_got<64, false>* got,
2924 Output_data_got_plt_x86_64* got_plt,
2925 Output_data_space* got_irelative,
2926 unsigned int plt_count)
2927 {
2928 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT)
2929 return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt,
2930 got_irelative, plt_count);
2931 return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt,
2932 got_irelative, plt_count);
2933 }
2934
2935 template<>
2936 Output_data_plt_x86_64<64>*
2937 Target_x86_64<64>::do_make_data_plt(Layout* layout,
2938 Output_data_got<64, false>* got,
2939 Output_data_got_plt_x86_64* got_plt,
2940 Output_data_space* got_irelative,
2941 unsigned int plt_count)
2942 {
2943 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT)
2944 return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt,
2945 got_irelative, plt_count);
2946 else if (parameters->options().bndplt())
2947 return new Output_data_plt_x86_64_bnd(layout, got, got_plt,
2948 got_irelative, plt_count);
2949 else
2950 return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt,
2951 got_irelative,
2952 plt_count);
2953 }
2954
2955 // Return the section for TLSDESC relocations.
2956
2957 template<int size>
2958 typename Target_x86_64<size>::Reloc_section*
2959 Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const
2960 {
2961 return this->plt_section()->rela_tlsdesc(layout);
2962 }
2963
2964 // Create a PLT entry for a global symbol.
2965
2966 template<int size>
2967 void
2968 Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout,
2969 Symbol* gsym)
2970 {
2971 if (gsym->has_plt_offset())
2972 return;
2973
2974 if (this->plt_ == NULL)
2975 this->make_plt_section(symtab, layout);
2976
2977 this->plt_->add_entry(symtab, layout, gsym);
2978 }
2979
2980 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
2981
2982 template<int size>
2983 void
2984 Target_x86_64<size>::make_local_ifunc_plt_entry(
2985 Symbol_table* symtab, Layout* layout,
2986 Sized_relobj_file<size, false>* relobj,
2987 unsigned int local_sym_index)
2988 {
2989 if (relobj->local_has_plt_offset(local_sym_index))
2990 return;
2991 if (this->plt_ == NULL)
2992 this->make_plt_section(symtab, layout);
2993 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
2994 relobj,
2995 local_sym_index);
2996 relobj->set_local_plt_offset(local_sym_index, plt_offset);
2997 }
2998
2999 // Return the number of entries in the PLT.
3000
3001 template<int size>
3002 unsigned int
3003 Target_x86_64<size>::plt_entry_count() const
3004 {
3005 if (this->plt_ == NULL)
3006 return 0;
3007 return this->plt_->entry_count();
3008 }
3009
3010 // Return the offset of the first non-reserved PLT entry.
3011
3012 template<int size>
3013 unsigned int
3014 Target_x86_64<size>::first_plt_entry_offset() const
3015 {
3016 if (this->plt_ == NULL)
3017 return 0;
3018 return this->plt_->first_plt_entry_offset();
3019 }
3020
3021 // Return the size of each PLT entry.
3022
3023 template<int size>
3024 unsigned int
3025 Target_x86_64<size>::plt_entry_size() const
3026 {
3027 if (this->plt_ == NULL)
3028 return 0;
3029 return this->plt_->get_plt_entry_size();
3030 }
3031
3032 // Create the GOT and PLT sections for an incremental update.
3033
3034 template<int size>
3035 Output_data_got_base*
3036 Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab,
3037 Layout* layout,
3038 unsigned int got_count,
3039 unsigned int plt_count)
3040 {
3041 gold_assert(this->got_ == NULL);
3042
3043 this->got_ = new Output_data_got<64, false>(got_count * 8);
3044 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
3045 (elfcpp::SHF_ALLOC
3046 | elfcpp::SHF_WRITE),
3047 this->got_, ORDER_RELRO_LAST,
3048 true);
3049
3050 // Add the three reserved entries.
3051 this->got_plt_ = new Output_data_got_plt_x86_64(layout, (plt_count + 3) * 8);
3052 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
3053 (elfcpp::SHF_ALLOC
3054 | elfcpp::SHF_WRITE),
3055 this->got_plt_, ORDER_NON_RELRO_FIRST,
3056 false);
3057
3058 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
3059 this->global_offset_table_ =
3060 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
3061 Symbol_table::PREDEFINED,
3062 this->got_plt_,
3063 0, 0, elfcpp::STT_OBJECT,
3064 elfcpp::STB_LOCAL,
3065 elfcpp::STV_HIDDEN, 0,
3066 false, false);
3067
3068 // If there are any TLSDESC relocations, they get GOT entries in
3069 // .got.plt after the jump slot entries.
3070 // FIXME: Get the count for TLSDESC entries.
3071 this->got_tlsdesc_ = new Output_data_got<64, false>(0);
3072 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
3073 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
3074 this->got_tlsdesc_,
3075 ORDER_NON_RELRO_FIRST, false);
3076
3077 // If there are any IRELATIVE relocations, they get GOT entries in
3078 // .got.plt after the jump slot and TLSDESC entries.
3079 this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT");
3080 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
3081 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
3082 this->got_irelative_,
3083 ORDER_NON_RELRO_FIRST, false);
3084
3085 // Create the PLT section.
3086 this->plt_ = this->make_data_plt(layout, this->got_,
3087 this->got_plt_,
3088 this->got_irelative_,
3089 plt_count);
3090
3091 // Add unwind information if requested.
3092 if (parameters->options().ld_generated_unwind_info())
3093 this->plt_->add_eh_frame(layout);
3094
3095 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
3096 elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR,
3097 this->plt_, ORDER_PLT, false);
3098
3099 // Make the sh_info field of .rela.plt point to .plt.
3100 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
3101 rela_plt_os->set_info_section(this->plt_->output_section());
3102
3103 // Create the rela_dyn section.
3104 this->rela_dyn_section(layout);
3105
3106 return this->got_;
3107 }
3108
3109 // Reserve a GOT entry for a local symbol, and regenerate any
3110 // necessary dynamic relocations.
3111
3112 template<int size>
3113 void
3114 Target_x86_64<size>::reserve_local_got_entry(
3115 unsigned int got_index,
3116 Sized_relobj<size, false>* obj,
3117 unsigned int r_sym,
3118 unsigned int got_type)
3119 {
3120 unsigned int got_offset = got_index * 8;
3121 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
3122
3123 this->got_->reserve_local(got_index, obj, r_sym, got_type);
3124 switch (got_type)
3125 {
3126 case GOT_TYPE_STANDARD:
3127 if (parameters->options().output_is_position_independent())
3128 rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
3129 this->got_, got_offset, 0, false);
3130 break;
3131 case GOT_TYPE_TLS_OFFSET:
3132 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
3133 this->got_, got_offset, 0);
3134 break;
3135 case GOT_TYPE_TLS_PAIR:
3136 this->got_->reserve_slot(got_index + 1);
3137 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64,
3138 this->got_, got_offset, 0);
3139 break;
3140 case GOT_TYPE_TLS_DESC:
3141 gold_fatal(_("TLS_DESC not yet supported for incremental linking"));
3142 // this->got_->reserve_slot(got_index + 1);
3143 // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
3144 // this->got_, got_offset, 0);
3145 break;
3146 default:
3147 gold_unreachable();
3148 }
3149 }
3150
3151 // Reserve a GOT entry for a global symbol, and regenerate any
3152 // necessary dynamic relocations.
3153
3154 template<int size>
3155 void
3156 Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index,
3157 Symbol* gsym,
3158 unsigned int got_type)
3159 {
3160 unsigned int got_offset = got_index * 8;
3161 Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
3162
3163 this->got_->reserve_global(got_index, gsym, got_type);
3164 switch (got_type)
3165 {
3166 case GOT_TYPE_STANDARD:
3167 if (!gsym->final_value_is_known())
3168 {
3169 if (gsym->is_from_dynobj()
3170 || gsym->is_undefined()
3171 || gsym->is_preemptible()
3172 || gsym->type() == elfcpp::STT_GNU_IFUNC)
3173 rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT,
3174 this->got_, got_offset, 0);
3175 else
3176 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
3177 this->got_, got_offset, 0, false);
3178 }
3179 break;
3180 case GOT_TYPE_TLS_OFFSET:
3181 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64,
3182 this->got_, got_offset, 0, false);
3183 break;
3184 case GOT_TYPE_TLS_PAIR:
3185 this->got_->reserve_slot(got_index + 1);
3186 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64,
3187 this->got_, got_offset, 0, false);
3188 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64,
3189 this->got_, got_offset + 8, 0, false);
3190 break;
3191 case GOT_TYPE_TLS_DESC:
3192 this->got_->reserve_slot(got_index + 1);
3193 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC,
3194 this->got_, got_offset, 0, false);
3195 break;
3196 default:
3197 gold_unreachable();
3198 }
3199 }
3200
3201 // Register an existing PLT entry for a global symbol.
3202
3203 template<int size>
3204 void
3205 Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab,
3206 Layout* layout,
3207 unsigned int plt_index,
3208 Symbol* gsym)
3209 {
3210 gold_assert(this->plt_ != NULL);
3211 gold_assert(!gsym->has_plt_offset());
3212
3213 this->plt_->reserve_slot(plt_index);
3214
3215 gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
3216
3217 unsigned int got_offset = (plt_index + 3) * 8;
3218 this->plt_->add_relocation(symtab, layout, gsym, got_offset);
3219 }
3220
3221 // Force a COPY relocation for a given symbol.
3222
3223 template<int size>
3224 void
3225 Target_x86_64<size>::emit_copy_reloc(
3226 Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset)
3227 {
3228 this->copy_relocs_.emit_copy_reloc(symtab,
3229 symtab->get_sized_symbol<size>(sym),
3230 os,
3231 offset,
3232 this->rela_dyn_section(NULL));
3233 }
3234
3235 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
3236
3237 template<int size>
3238 void
3239 Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab,
3240 Layout* layout)
3241 {
3242 if (this->tls_base_symbol_defined_)
3243 return;
3244
3245 Output_segment* tls_segment = layout->tls_segment();
3246 if (tls_segment != NULL)
3247 {
3248 bool is_exec = parameters->options().output_is_executable();
3249 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
3250 Symbol_table::PREDEFINED,
3251 tls_segment, 0, 0,
3252 elfcpp::STT_TLS,
3253 elfcpp::STB_LOCAL,
3254 elfcpp::STV_HIDDEN, 0,
3255 (is_exec
3256 ? Symbol::SEGMENT_END
3257 : Symbol::SEGMENT_START),
3258 true);
3259 }
3260 this->tls_base_symbol_defined_ = true;
3261 }
3262
3263 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
3264
3265 template<int size>
3266 void
3267 Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab,
3268 Layout* layout)
3269 {
3270 if (this->plt_ == NULL)
3271 this->make_plt_section(symtab, layout);
3272
3273 if (!this->plt_->has_tlsdesc_entry())
3274 {
3275 // Allocate the TLSDESC_GOT entry.
3276 Output_data_got<64, false>* got = this->got_section(symtab, layout);
3277 unsigned int got_offset = got->add_constant(0);
3278
3279 // Allocate the TLSDESC_PLT entry.
3280 this->plt_->reserve_tlsdesc_entry(got_offset);
3281 }
3282 }
3283
3284 // Create a GOT entry for the TLS module index.
3285
3286 template<int size>
3287 unsigned int
3288 Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
3289 Sized_relobj_file<size, false>* object)
3290 {
3291 if (this->got_mod_index_offset_ == -1U)
3292 {
3293 gold_assert(symtab != NULL && layout != NULL && object != NULL);
3294 Reloc_section* rela_dyn = this->rela_dyn_section(layout);
3295 Output_data_got<64, false>* got = this->got_section(symtab, layout);
3296 unsigned int got_offset = got->add_constant(0);
3297 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
3298 got_offset, 0);
3299 got->add_constant(0);
3300 this->got_mod_index_offset_ = got_offset;
3301 }
3302 return this->got_mod_index_offset_;
3303 }
3304
3305 // Optimize the TLS relocation type based on what we know about the
3306 // symbol. IS_FINAL is true if the final address of this symbol is
3307 // known at link time.
3308
3309 template<int size>
3310 tls::Tls_optimization
3311 Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type)
3312 {
3313 // If we are generating a shared library, then we can't do anything
3314 // in the linker.
3315 if (parameters->options().shared())
3316 return tls::TLSOPT_NONE;
3317
3318 switch (r_type)
3319 {
3320 case elfcpp::R_X86_64_TLSGD:
3321 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
3322 case elfcpp::R_X86_64_TLSDESC_CALL:
3323 // These are General-Dynamic which permits fully general TLS
3324 // access. Since we know that we are generating an executable,
3325 // we can convert this to Initial-Exec. If we also know that
3326 // this is a local symbol, we can further switch to Local-Exec.
3327 if (is_final)
3328 return tls::TLSOPT_TO_LE;
3329 return tls::TLSOPT_TO_IE;
3330
3331 case elfcpp::R_X86_64_TLSLD:
3332 // This is Local-Dynamic, which refers to a local symbol in the
3333 // dynamic TLS block. Since we know that we generating an
3334 // executable, we can switch to Local-Exec.
3335 return tls::TLSOPT_TO_LE;
3336
3337 case elfcpp::R_X86_64_DTPOFF32:
3338 case elfcpp::R_X86_64_DTPOFF64:
3339 // Another Local-Dynamic reloc.
3340 return tls::TLSOPT_TO_LE;
3341
3342 case elfcpp::R_X86_64_GOTTPOFF:
3343 // These are Initial-Exec relocs which get the thread offset
3344 // from the GOT. If we know that we are linking against the
3345 // local symbol, we can switch to Local-Exec, which links the
3346 // thread offset into the instruction.
3347 if (is_final)
3348 return tls::TLSOPT_TO_LE;
3349 return tls::TLSOPT_NONE;
3350
3351 case elfcpp::R_X86_64_TPOFF32:
3352 // When we already have Local-Exec, there is nothing further we
3353 // can do.
3354 return tls::TLSOPT_NONE;
3355
3356 default:
3357 gold_unreachable();
3358 }
3359 }
3360
3361 // Get the Reference_flags for a particular relocation.
3362
3363 template<int size>
3364 int
3365 Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type)
3366 {
3367 switch (r_type)
3368 {
3369 case elfcpp::R_X86_64_NONE:
3370 case elfcpp::R_X86_64_GNU_VTINHERIT:
3371 case elfcpp::R_X86_64_GNU_VTENTRY:
3372 case elfcpp::R_X86_64_GOTPC32:
3373 case elfcpp::R_X86_64_GOTPC64:
3374 // No symbol reference.
3375 return 0;
3376
3377 case elfcpp::R_X86_64_64:
3378 case elfcpp::R_X86_64_32:
3379 case elfcpp::R_X86_64_32S:
3380 case elfcpp::R_X86_64_16:
3381 case elfcpp::R_X86_64_8:
3382 return Symbol::ABSOLUTE_REF;
3383
3384 case elfcpp::R_X86_64_PC64:
3385 case elfcpp::R_X86_64_PC32:
3386 case elfcpp::R_X86_64_PC32_BND:
3387 case elfcpp::R_X86_64_PC16:
3388 case elfcpp::R_X86_64_PC8:
3389 case elfcpp::R_X86_64_GOTOFF64:
3390 return Symbol::RELATIVE_REF;
3391
3392 case elfcpp::R_X86_64_PLT32:
3393 case elfcpp::R_X86_64_PLT32_BND:
3394 case elfcpp::R_X86_64_PLTOFF64:
3395 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
3396
3397 case elfcpp::R_X86_64_GOT64:
3398 case elfcpp::R_X86_64_GOT32:
3399 case elfcpp::R_X86_64_GOTPCREL64:
3400 case elfcpp::R_X86_64_GOTPCREL:
3401 case elfcpp::R_X86_64_GOTPCRELX:
3402 case elfcpp::R_X86_64_REX_GOTPCRELX:
3403 case elfcpp::R_X86_64_GOTPLT64:
3404 // Absolute in GOT.
3405 return Symbol::ABSOLUTE_REF;
3406
3407 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3408 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3409 case elfcpp::R_X86_64_TLSDESC_CALL:
3410 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3411 case elfcpp::R_X86_64_DTPOFF32:
3412 case elfcpp::R_X86_64_DTPOFF64:
3413 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3414 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3415 return Symbol::TLS_REF;
3416
3417 case elfcpp::R_X86_64_COPY:
3418 case elfcpp::R_X86_64_GLOB_DAT:
3419 case elfcpp::R_X86_64_JUMP_SLOT:
3420 case elfcpp::R_X86_64_RELATIVE:
3421 case elfcpp::R_X86_64_IRELATIVE:
3422 case elfcpp::R_X86_64_TPOFF64:
3423 case elfcpp::R_X86_64_DTPMOD64:
3424 case elfcpp::R_X86_64_TLSDESC:
3425 case elfcpp::R_X86_64_SIZE32:
3426 case elfcpp::R_X86_64_SIZE64:
3427 default:
3428 // Not expected. We will give an error later.
3429 return 0;
3430 }
3431 }
3432
3433 // Report an unsupported relocation against a local symbol.
3434
3435 template<int size>
3436 void
3437 Target_x86_64<size>::Scan::unsupported_reloc_local(
3438 Sized_relobj_file<size, false>* object,
3439 unsigned int r_type)
3440 {
3441 gold_error(_("%s: unsupported reloc %u against local symbol"),
3442 object->name().c_str(), r_type);
3443 }
3444
3445 // We are about to emit a dynamic relocation of type R_TYPE. If the
3446 // dynamic linker does not support it, issue an error. The GNU linker
3447 // only issues a non-PIC error for an allocated read-only section.
3448 // Here we know the section is allocated, but we don't know that it is
3449 // read-only. But we check for all the relocation types which the
3450 // glibc dynamic linker supports, so it seems appropriate to issue an
3451 // error even if the section is not read-only. If GSYM is not NULL,
3452 // it is the symbol the relocation is against; if it is NULL, the
3453 // relocation is against a local symbol.
3454
3455 template<int size>
3456 void
3457 Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type,
3458 Symbol* gsym)
3459 {
3460 switch (r_type)
3461 {
3462 // These are the relocation types supported by glibc for x86_64
3463 // which should always work.
3464 case elfcpp::R_X86_64_RELATIVE:
3465 case elfcpp::R_X86_64_IRELATIVE:
3466 case elfcpp::R_X86_64_GLOB_DAT:
3467 case elfcpp::R_X86_64_JUMP_SLOT:
3468 case elfcpp::R_X86_64_DTPMOD64:
3469 case elfcpp::R_X86_64_DTPOFF64:
3470 case elfcpp::R_X86_64_TPOFF64:
3471 case elfcpp::R_X86_64_64:
3472 case elfcpp::R_X86_64_COPY:
3473 return;
3474
3475 // glibc supports these reloc types, but they can overflow.
3476 case elfcpp::R_X86_64_PC32:
3477 case elfcpp::R_X86_64_PC32_BND:
3478 // A PC relative reference is OK against a local symbol or if
3479 // the symbol is defined locally.
3480 if (gsym == NULL
3481 || (!gsym->is_from_dynobj()
3482 && !gsym->is_undefined()
3483 && !gsym->is_preemptible()))
3484 return;
3485 // Fall through.
3486 case elfcpp::R_X86_64_32:
3487 // R_X86_64_32 is OK for x32.
3488 if (size == 32 && r_type == elfcpp::R_X86_64_32)
3489 return;
3490 if (this->issued_non_pic_error_)
3491 return;
3492 gold_assert(parameters->options().output_is_position_independent());
3493 if (gsym == NULL)
3494 object->error(_("requires dynamic R_X86_64_32 reloc which may "
3495 "overflow at runtime; recompile with -fPIC"));
3496 else
3497 {
3498 const char *r_name;
3499 switch (r_type)
3500 {
3501 case elfcpp::R_X86_64_32:
3502 r_name = "R_X86_64_32";
3503 break;
3504 case elfcpp::R_X86_64_PC32:
3505 r_name = "R_X86_64_PC32";
3506 break;
3507 case elfcpp::R_X86_64_PC32_BND:
3508 r_name = "R_X86_64_PC32_BND";
3509 break;
3510 default:
3511 gold_unreachable();
3512 break;
3513 }
3514 object->error(_("requires dynamic %s reloc against '%s' "
3515 "which may overflow at runtime; recompile "
3516 "with -fPIC"),
3517 r_name, gsym->name());
3518 }
3519 this->issued_non_pic_error_ = true;
3520 return;
3521
3522 default:
3523 // This prevents us from issuing more than one error per reloc
3524 // section. But we can still wind up issuing more than one
3525 // error per object file.
3526 if (this->issued_non_pic_error_)
3527 return;
3528 gold_assert(parameters->options().output_is_position_independent());
3529 object->error(_("requires unsupported dynamic reloc %u; "
3530 "recompile with -fPIC"),
3531 r_type);
3532 this->issued_non_pic_error_ = true;
3533 return;
3534
3535 case elfcpp::R_X86_64_NONE:
3536 gold_unreachable();
3537 }
3538 }
3539
3540 // Return whether we need to make a PLT entry for a relocation of the
3541 // given type against a STT_GNU_IFUNC symbol.
3542
3543 template<int size>
3544 bool
3545 Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc(
3546 Sized_relobj_file<size, false>* object,
3547 unsigned int r_type)
3548 {
3549 int flags = Scan::get_reference_flags(r_type);
3550 if (flags & Symbol::TLS_REF)
3551 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
3552 object->name().c_str(), r_type);
3553 return flags != 0;
3554 }
3555
3556 // Scan a relocation for a local symbol.
3557
3558 template<int size>
3559 inline void
3560 Target_x86_64<size>::Scan::local(Symbol_table* symtab,
3561 Layout* layout,
3562 Target_x86_64<size>* target,
3563 Sized_relobj_file<size, false>* object,
3564 unsigned int data_shndx,
3565 Output_section* output_section,
3566 const elfcpp::Rela<size, false>& reloc,
3567 unsigned int r_type,
3568 const elfcpp::Sym<size, false>& lsym,
3569 bool is_discarded)
3570 {
3571 if (is_discarded)
3572 return;
3573
3574 // A local STT_GNU_IFUNC symbol may require a PLT entry.
3575 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
3576 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
3577 {
3578 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3579 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
3580 }
3581
3582 switch (r_type)
3583 {
3584 case elfcpp::R_X86_64_NONE:
3585 case elfcpp::R_X86_64_GNU_VTINHERIT:
3586 case elfcpp::R_X86_64_GNU_VTENTRY:
3587 break;
3588
3589 case elfcpp::R_X86_64_64:
3590 // If building a shared library (or a position-independent
3591 // executable), we need to create a dynamic relocation for this
3592 // location. The relocation applied at link time will apply the
3593 // link-time value, so we flag the location with an
3594 // R_X86_64_RELATIVE relocation so the dynamic loader can
3595 // relocate it easily.
3596 if (parameters->options().output_is_position_independent())
3597 {
3598 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3599 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
3600 rela_dyn->add_local_relative(object, r_sym,
3601 (size == 32
3602 ? elfcpp::R_X86_64_RELATIVE64
3603 : elfcpp::R_X86_64_RELATIVE),
3604 output_section, data_shndx,
3605 reloc.get_r_offset(),
3606 reloc.get_r_addend(), is_ifunc);
3607 }
3608 break;
3609
3610 case elfcpp::R_X86_64_32:
3611 case elfcpp::R_X86_64_32S:
3612 case elfcpp::R_X86_64_16:
3613 case elfcpp::R_X86_64_8:
3614 // If building a shared library (or a position-independent
3615 // executable), we need to create a dynamic relocation for this
3616 // location. We can't use an R_X86_64_RELATIVE relocation
3617 // because that is always a 64-bit relocation.
3618 if (parameters->options().output_is_position_independent())
3619 {
3620 // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32.
3621 if (size == 32 && r_type == elfcpp::R_X86_64_32)
3622 {
3623 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3624 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
3625 rela_dyn->add_local_relative(object, r_sym,
3626 elfcpp::R_X86_64_RELATIVE,
3627 output_section, data_shndx,
3628 reloc.get_r_offset(),
3629 reloc.get_r_addend(), is_ifunc);
3630 break;
3631 }
3632
3633 this->check_non_pic(object, r_type, NULL);
3634
3635 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
3636 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3637 if (lsym.get_st_type() != elfcpp::STT_SECTION)
3638 rela_dyn->add_local(object, r_sym, r_type, output_section,
3639 data_shndx, reloc.get_r_offset(),
3640 reloc.get_r_addend());
3641 else
3642 {
3643 gold_assert(lsym.get_st_value() == 0);
3644 unsigned int shndx = lsym.get_st_shndx();
3645 bool is_ordinary;
3646 shndx = object->adjust_sym_shndx(r_sym, shndx,
3647 &is_ordinary);
3648 if (!is_ordinary)
3649 object->error(_("section symbol %u has bad shndx %u"),
3650 r_sym, shndx);
3651 else
3652 rela_dyn->add_local_section(object, shndx,
3653 r_type, output_section,
3654 data_shndx, reloc.get_r_offset(),
3655 reloc.get_r_addend());
3656 }
3657 }
3658 break;
3659
3660 case elfcpp::R_X86_64_PC64:
3661 case elfcpp::R_X86_64_PC32:
3662 case elfcpp::R_X86_64_PC32_BND:
3663 case elfcpp::R_X86_64_PC16:
3664 case elfcpp::R_X86_64_PC8:
3665 break;
3666
3667 case elfcpp::R_X86_64_PLT32:
3668 case elfcpp::R_X86_64_PLT32_BND:
3669 // Since we know this is a local symbol, we can handle this as a
3670 // PC32 reloc.
3671 break;
3672
3673 case elfcpp::R_X86_64_GOTPC32:
3674 case elfcpp::R_X86_64_GOTOFF64:
3675 case elfcpp::R_X86_64_GOTPC64:
3676 case elfcpp::R_X86_64_PLTOFF64:
3677 // We need a GOT section.
3678 target->got_section(symtab, layout);
3679 // For PLTOFF64, we'd normally want a PLT section, but since we
3680 // know this is a local symbol, no PLT is needed.
3681 break;
3682
3683 case elfcpp::R_X86_64_GOT64:
3684 case elfcpp::R_X86_64_GOT32:
3685 case elfcpp::R_X86_64_GOTPCREL64:
3686 case elfcpp::R_X86_64_GOTPCREL:
3687 case elfcpp::R_X86_64_GOTPCRELX:
3688 case elfcpp::R_X86_64_REX_GOTPCRELX:
3689 case elfcpp::R_X86_64_GOTPLT64:
3690 {
3691 // The symbol requires a GOT section.
3692 Output_data_got<64, false>* got = target->got_section(symtab, layout);
3693
3694 // If the relocation symbol isn't IFUNC,
3695 // and is local, then we will convert
3696 // mov foo@GOTPCREL(%rip), %reg
3697 // to lea foo(%rip), %reg.
3698 // in Relocate::relocate.
3699 if (!parameters->incremental()
3700 && (r_type == elfcpp::R_X86_64_GOTPCREL
3701 || r_type == elfcpp::R_X86_64_GOTPCRELX
3702 || r_type == elfcpp::R_X86_64_REX_GOTPCRELX)
3703 && reloc.get_r_offset() >= 2
3704 && !is_ifunc)
3705 {
3706 section_size_type stype;
3707 const unsigned char* view = object->section_contents(data_shndx,
3708 &stype, true);
3709 if (view[reloc.get_r_offset() - 2] == 0x8b)
3710 break;
3711 }
3712
3713 // The symbol requires a GOT entry.
3714 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3715
3716 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
3717 // lets function pointers compare correctly with shared
3718 // libraries. Otherwise we would need an IRELATIVE reloc.
3719 bool is_new;
3720 if (is_ifunc)
3721 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
3722 else
3723 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
3724 if (is_new)
3725 {
3726 // If we are generating a shared object, we need to add a
3727 // dynamic relocation for this symbol's GOT entry.
3728 if (parameters->options().output_is_position_independent())
3729 {
3730 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
3731 // R_X86_64_RELATIVE assumes a 64-bit relocation.
3732 if (r_type != elfcpp::R_X86_64_GOT32)
3733 {
3734 unsigned int got_offset =
3735 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
3736 rela_dyn->add_local_relative(object, r_sym,
3737 elfcpp::R_X86_64_RELATIVE,
3738 got, got_offset, 0, is_ifunc);
3739 }
3740 else
3741 {
3742 this->check_non_pic(object, r_type, NULL);
3743
3744 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
3745 rela_dyn->add_local(
3746 object, r_sym, r_type, got,
3747 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
3748 }
3749 }
3750 }
3751 // For GOTPLT64, we'd normally want a PLT section, but since
3752 // we know this is a local symbol, no PLT is needed.
3753 }
3754 break;
3755
3756 case elfcpp::R_X86_64_COPY:
3757 case elfcpp::R_X86_64_GLOB_DAT:
3758 case elfcpp::R_X86_64_JUMP_SLOT:
3759 case elfcpp::R_X86_64_RELATIVE:
3760 case elfcpp::R_X86_64_IRELATIVE:
3761 // These are outstanding tls relocs, which are unexpected when linking
3762 case elfcpp::R_X86_64_TPOFF64:
3763 case elfcpp::R_X86_64_DTPMOD64:
3764 case elfcpp::R_X86_64_TLSDESC:
3765 gold_error(_("%s: unexpected reloc %u in object file"),
3766 object->name().c_str(), r_type);
3767 break;
3768
3769 // These are initial tls relocs, which are expected when linking
3770 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
3771 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
3772 case elfcpp::R_X86_64_TLSDESC_CALL:
3773 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3774 case elfcpp::R_X86_64_DTPOFF32:
3775 case elfcpp::R_X86_64_DTPOFF64:
3776 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3777 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3778 {
3779 bool output_is_shared = parameters->options().shared();
3780 const tls::Tls_optimization optimized_type
3781 = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared,
3782 r_type);
3783 switch (r_type)
3784 {
3785 case elfcpp::R_X86_64_TLSGD: // General-dynamic
3786 if (optimized_type == tls::TLSOPT_NONE)
3787 {
3788 // Create a pair of GOT entries for the module index and
3789 // dtv-relative offset.
3790 Output_data_got<64, false>* got
3791 = target->got_section(symtab, layout);
3792 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3793 unsigned int shndx = lsym.get_st_shndx();
3794 bool is_ordinary;
3795 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
3796 if (!is_ordinary)
3797 object->error(_("local symbol %u has bad shndx %u"),
3798 r_sym, shndx);
3799 else
3800 got->add_local_pair_with_rel(object, r_sym,
3801 shndx,
3802 GOT_TYPE_TLS_PAIR,
3803 target->rela_dyn_section(layout),
3804 elfcpp::R_X86_64_DTPMOD64);
3805 }
3806 else if (optimized_type != tls::TLSOPT_TO_LE)
3807 unsupported_reloc_local(object, r_type);
3808 break;
3809
3810 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
3811 target->define_tls_base_symbol(symtab, layout);
3812 if (optimized_type == tls::TLSOPT_NONE)
3813 {
3814 // Create reserved PLT and GOT entries for the resolver.
3815 target->reserve_tlsdesc_entries(symtab, layout);
3816
3817 // Generate a double GOT entry with an
3818 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
3819 // is resolved lazily, so the GOT entry needs to be in
3820 // an area in .got.plt, not .got. Call got_section to
3821 // make sure the section has been created.
3822 target->got_section(symtab, layout);
3823 Output_data_got<64, false>* got = target->got_tlsdesc_section();
3824 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3825 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
3826 {
3827 unsigned int got_offset = got->add_constant(0);
3828 got->add_constant(0);
3829 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
3830 got_offset);
3831 Reloc_section* rt = target->rela_tlsdesc_section(layout);
3832 // We store the arguments we need in a vector, and
3833 // use the index into the vector as the parameter
3834 // to pass to the target specific routines.
3835 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
3836 void* arg = reinterpret_cast<void*>(intarg);
3837 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
3838 got, got_offset, 0);
3839 }
3840 }
3841 else if (optimized_type != tls::TLSOPT_TO_LE)
3842 unsupported_reloc_local(object, r_type);
3843 break;
3844
3845 case elfcpp::R_X86_64_TLSDESC_CALL:
3846 break;
3847
3848 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
3849 if (optimized_type == tls::TLSOPT_NONE)
3850 {
3851 // Create a GOT entry for the module index.
3852 target->got_mod_index_entry(symtab, layout, object);
3853 }
3854 else if (optimized_type != tls::TLSOPT_TO_LE)
3855 unsupported_reloc_local(object, r_type);
3856 break;
3857
3858 case elfcpp::R_X86_64_DTPOFF32:
3859 case elfcpp::R_X86_64_DTPOFF64:
3860 break;
3861
3862 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
3863 layout->set_has_static_tls();
3864 if (optimized_type == tls::TLSOPT_NONE)
3865 {
3866 // Create a GOT entry for the tp-relative offset.
3867 Output_data_got<64, false>* got
3868 = target->got_section(symtab, layout);
3869 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
3870 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET,
3871 target->rela_dyn_section(layout),
3872 elfcpp::R_X86_64_TPOFF64);
3873 }
3874 else if (optimized_type != tls::TLSOPT_TO_LE)
3875 unsupported_reloc_local(object, r_type);
3876 break;
3877
3878 case elfcpp::R_X86_64_TPOFF32: // Local-exec
3879 layout->set_has_static_tls();
3880 if (output_is_shared)
3881 unsupported_reloc_local(object, r_type);
3882 break;
3883
3884 default:
3885 gold_unreachable();
3886 }
3887 }
3888 break;
3889
3890 case elfcpp::R_X86_64_SIZE32:
3891 case elfcpp::R_X86_64_SIZE64:
3892 default:
3893 gold_error(_("%s: unsupported reloc %u against local symbol"),
3894 object->name().c_str(), r_type);
3895 break;
3896 }
3897 }
3898
3899
3900 // Report an unsupported relocation against a global symbol.
3901
3902 template<int size>
3903 void
3904 Target_x86_64<size>::Scan::unsupported_reloc_global(
3905 Sized_relobj_file<size, false>* object,
3906 unsigned int r_type,
3907 Symbol* gsym)
3908 {
3909 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
3910 object->name().c_str(), r_type, gsym->demangled_name().c_str());
3911 }
3912
3913 // Returns true if this relocation type could be that of a function pointer.
3914 template<int size>
3915 inline bool
3916 Target_x86_64<size>::Scan::possible_function_pointer_reloc(
3917 Sized_relobj_file<size, false>* src_obj,
3918 unsigned int src_indx,
3919 unsigned int r_offset,
3920 unsigned int r_type)
3921 {
3922 switch (r_type)
3923 {
3924 case elfcpp::R_X86_64_64:
3925 case elfcpp::R_X86_64_32:
3926 case elfcpp::R_X86_64_32S:
3927 case elfcpp::R_X86_64_16:
3928 case elfcpp::R_X86_64_8:
3929 case elfcpp::R_X86_64_GOT64:
3930 case elfcpp::R_X86_64_GOT32:
3931 case elfcpp::R_X86_64_GOTPCREL64:
3932 case elfcpp::R_X86_64_GOTPCREL:
3933 case elfcpp::R_X86_64_GOTPCRELX:
3934 case elfcpp::R_X86_64_REX_GOTPCRELX:
3935 case elfcpp::R_X86_64_GOTPLT64:
3936 {
3937 return true;
3938 }
3939 case elfcpp::R_X86_64_PC32:
3940 {
3941 // This relocation may be used both for function calls and
3942 // for taking address of a function. We distinguish between
3943 // them by checking the opcodes.
3944 uint64_t sh_flags = src_obj->section_flags(src_indx);
3945 bool is_executable = (sh_flags & elfcpp::SHF_EXECINSTR) != 0;
3946 if (is_executable)
3947 {
3948 section_size_type stype;
3949 const unsigned char* view = src_obj->section_contents(src_indx,
3950 &stype,
3951 true);
3952
3953 // call
3954 if (r_offset >= 1
3955 && view[r_offset - 1] == 0xe8)
3956 return false;
3957
3958 // jmp
3959 if (r_offset >= 1
3960 && view[r_offset - 1] == 0xe9)
3961 return false;
3962
3963 // jo/jno/jb/jnb/je/jne/jna/ja/js/jns/jp/jnp/jl/jge/jle/jg
3964 if (r_offset >= 2
3965 && view[r_offset - 2] == 0x0f
3966 && view[r_offset - 1] >= 0x80
3967 && view[r_offset - 1] <= 0x8f)
3968 return false;
3969 }
3970
3971 // Be conservative and treat all others as function pointers.
3972 return true;
3973 }
3974 }
3975 return false;
3976 }
3977
3978 // For safe ICF, scan a relocation for a local symbol to check if it
3979 // corresponds to a function pointer being taken. In that case mark
3980 // the function whose pointer was taken as not foldable.
3981
3982 template<int size>
3983 inline bool
3984 Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer(
3985 Symbol_table* ,
3986 Layout* ,
3987 Target_x86_64<size>* ,
3988 Sized_relobj_file<size, false>* src_obj,
3989 unsigned int src_indx,
3990 Output_section* ,
3991 const elfcpp::Rela<size, false>& reloc,
3992 unsigned int r_type,
3993 const elfcpp::Sym<size, false>&)
3994 {
3995 // When building a shared library, do not fold any local symbols as it is
3996 // not possible to distinguish pointer taken versus a call by looking at
3997 // the relocation types.
3998 if (parameters->options().shared())
3999 return true;
4000
4001 return possible_function_pointer_reloc(src_obj, src_indx,
4002 reloc.get_r_offset(), r_type);
4003 }
4004
4005 // For safe ICF, scan a relocation for a global symbol to check if it
4006 // corresponds to a function pointer being taken. In that case mark
4007 // the function whose pointer was taken as not foldable.
4008
4009 template<int size>
4010 inline bool
4011 Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer(
4012 Symbol_table*,
4013 Layout* ,
4014 Target_x86_64<size>* ,
4015 Sized_relobj_file<size, false>* src_obj,
4016 unsigned int src_indx,
4017 Output_section* ,
4018 const elfcpp::Rela<size, false>& reloc,
4019 unsigned int r_type,
4020 Symbol* gsym)
4021 {
4022 // When building a shared library, do not fold symbols whose visibility
4023 // is hidden, internal or protected.
4024 if (parameters->options().shared()
4025 && (gsym->visibility() == elfcpp::STV_INTERNAL
4026 || gsym->visibility() == elfcpp::STV_PROTECTED
4027 || gsym->visibility() == elfcpp::STV_HIDDEN))
4028 return true;
4029
4030 return possible_function_pointer_reloc(src_obj, src_indx,
4031 reloc.get_r_offset(), r_type);
4032 }
4033
4034 // Scan a relocation for a global symbol.
4035
4036 template<int size>
4037 inline void
4038 Target_x86_64<size>::Scan::global(Symbol_table* symtab,
4039 Layout* layout,
4040 Target_x86_64<size>* target,
4041 Sized_relobj_file<size, false>* object,
4042 unsigned int data_shndx,
4043 Output_section* output_section,
4044 const elfcpp::Rela<size, false>& reloc,
4045 unsigned int r_type,
4046 Symbol* gsym)
4047 {
4048 // A STT_GNU_IFUNC symbol may require a PLT entry.
4049 if (gsym->type() == elfcpp::STT_GNU_IFUNC
4050 && this->reloc_needs_plt_for_ifunc(object, r_type))
4051 target->make_plt_entry(symtab, layout, gsym);
4052
4053 switch (r_type)
4054 {
4055 case elfcpp::R_X86_64_NONE:
4056 case elfcpp::R_X86_64_GNU_VTINHERIT:
4057 case elfcpp::R_X86_64_GNU_VTENTRY:
4058 break;
4059
4060 case elfcpp::R_X86_64_64:
4061 case elfcpp::R_X86_64_32:
4062 case elfcpp::R_X86_64_32S:
4063 case elfcpp::R_X86_64_16:
4064 case elfcpp::R_X86_64_8:
4065 {
4066 // Make a PLT entry if necessary.
4067 if (gsym->needs_plt_entry())
4068 {
4069 target->make_plt_entry(symtab, layout, gsym);
4070 // Since this is not a PC-relative relocation, we may be
4071 // taking the address of a function. In that case we need to
4072 // set the entry in the dynamic symbol table to the address of
4073 // the PLT entry.
4074 if (gsym->is_from_dynobj() && !parameters->options().shared())
4075 gsym->set_needs_dynsym_value();
4076 }
4077 // Make a dynamic relocation if necessary.
4078 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
4079 {
4080 if (!parameters->options().output_is_position_independent()
4081 && gsym->may_need_copy_reloc())
4082 {
4083 target->copy_reloc(symtab, layout, object,
4084 data_shndx, output_section, gsym, reloc);
4085 }
4086 else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
4087 || (size == 32 && r_type == elfcpp::R_X86_64_32))
4088 && gsym->type() == elfcpp::STT_GNU_IFUNC
4089 && gsym->can_use_relative_reloc(false)
4090 && !gsym->is_from_dynobj()
4091 && !gsym->is_undefined()
4092 && !gsym->is_preemptible())
4093 {
4094 // Use an IRELATIVE reloc for a locally defined
4095 // STT_GNU_IFUNC symbol. This makes a function
4096 // address in a PIE executable match the address in a
4097 // shared library that it links against.
4098 Reloc_section* rela_dyn =
4099 target->rela_irelative_section(layout);
4100 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
4101 rela_dyn->add_symbolless_global_addend(gsym, r_type,
4102 output_section, object,
4103 data_shndx,
4104 reloc.get_r_offset(),
4105 reloc.get_r_addend());
4106 }
4107 else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
4108 || (size == 32 && r_type == elfcpp::R_X86_64_32))
4109 && gsym->can_use_relative_reloc(false))
4110 {
4111 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
4112 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
4113 output_section, object,
4114 data_shndx,
4115 reloc.get_r_offset(),
4116 reloc.get_r_addend(), false);
4117 }
4118 else
4119 {
4120 this->check_non_pic(object, r_type, gsym);
4121 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
4122 rela_dyn->add_global(gsym, r_type, output_section, object,
4123 data_shndx, reloc.get_r_offset(),
4124 reloc.get_r_addend());
4125 }
4126 }
4127 }
4128 break;
4129
4130 case elfcpp::R_X86_64_PC64:
4131 case elfcpp::R_X86_64_PC32:
4132 case elfcpp::R_X86_64_PC32_BND:
4133 case elfcpp::R_X86_64_PC16:
4134 case elfcpp::R_X86_64_PC8:
4135 {
4136 // Make a PLT entry if necessary.
4137 if (gsym->needs_plt_entry())
4138 target->make_plt_entry(symtab, layout, gsym);
4139 // Make a dynamic relocation if necessary.
4140 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
4141 {
4142 if (parameters->options().output_is_executable()
4143 && gsym->may_need_copy_reloc())
4144 {
4145 target->copy_reloc(symtab, layout, object,
4146 data_shndx, output_section, gsym, reloc);
4147 }
4148 else
4149 {
4150 this->check_non_pic(object, r_type, gsym);
4151 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
4152 rela_dyn->add_global(gsym, r_type, output_section, object,
4153 data_shndx, reloc.get_r_offset(),
4154 reloc.get_r_addend());
4155 }
4156 }
4157 }
4158 break;
4159
4160 case elfcpp::R_X86_64_GOT64:
4161 case elfcpp::R_X86_64_GOT32:
4162 case elfcpp::R_X86_64_GOTPCREL64:
4163 case elfcpp::R_X86_64_GOTPCREL:
4164 case elfcpp::R_X86_64_GOTPCRELX:
4165 case elfcpp::R_X86_64_REX_GOTPCRELX:
4166 case elfcpp::R_X86_64_GOTPLT64:
4167 {
4168 // The symbol requires a GOT entry.
4169 Output_data_got<64, false>* got = target->got_section(symtab, layout);
4170
4171 // If we convert this from
4172 // mov foo@GOTPCREL(%rip), %reg
4173 // to lea foo(%rip), %reg.
4174 // OR
4175 // if we convert
4176 // (callq|jmpq) *foo@GOTPCRELX(%rip) to
4177 // (callq|jmpq) foo
4178 // in Relocate::relocate, then there is nothing to do here.
4179 // We cannot make these optimizations in incremental linking mode,
4180 // because we look at the opcode to decide whether or not to make
4181 // change, and during an incremental update, the change may have
4182 // already been applied.
4183
4184 Lazy_view<size> view(object, data_shndx);
4185 size_t r_offset = reloc.get_r_offset();
4186 if (!parameters->incremental()
4187 && r_offset >= 2
4188 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
4189 r_offset, &view))
4190 break;
4191
4192 if (!parameters->incremental()
4193 && r_offset >= 2
4194 && Target_x86_64<size>::can_convert_callq_to_direct(gsym, r_type,
4195 r_offset,
4196 &view))
4197 break;
4198
4199 if (gsym->final_value_is_known())
4200 {
4201 // For a STT_GNU_IFUNC symbol we want the PLT address.
4202 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
4203 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
4204 else
4205 got->add_global(gsym, GOT_TYPE_STANDARD);
4206 }
4207 else
4208 {
4209 // If this symbol is not fully resolved, we need to add a
4210 // dynamic relocation for it.
4211 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
4212
4213 // Use a GLOB_DAT rather than a RELATIVE reloc if:
4214 //
4215 // 1) The symbol may be defined in some other module.
4216 //
4217 // 2) We are building a shared library and this is a
4218 // protected symbol; using GLOB_DAT means that the dynamic
4219 // linker can use the address of the PLT in the main
4220 // executable when appropriate so that function address
4221 // comparisons work.
4222 //
4223 // 3) This is a STT_GNU_IFUNC symbol in position dependent
4224 // code, again so that function address comparisons work.
4225 if (gsym->is_from_dynobj()
4226 || gsym->is_undefined()
4227 || gsym->is_preemptible()
4228 || (gsym->visibility() == elfcpp::STV_PROTECTED
4229 && parameters->options().shared())
4230 || (gsym->type() == elfcpp::STT_GNU_IFUNC
4231 && parameters->options().output_is_position_independent()))
4232 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn,
4233 elfcpp::R_X86_64_GLOB_DAT);
4234 else
4235 {
4236 // For a STT_GNU_IFUNC symbol we want to write the PLT
4237 // offset into the GOT, so that function pointer
4238 // comparisons work correctly.
4239 bool is_new;
4240 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
4241 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
4242 else
4243 {
4244 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
4245 // Tell the dynamic linker to use the PLT address
4246 // when resolving relocations.
4247 if (gsym->is_from_dynobj()
4248 && !parameters->options().shared())
4249 gsym->set_needs_dynsym_value();
4250 }
4251 if (is_new)
4252 {
4253 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
4254 rela_dyn->add_global_relative(gsym,
4255 elfcpp::R_X86_64_RELATIVE,
4256 got, got_off, 0, false);
4257 }
4258 }
4259 }
4260 }
4261 break;
4262
4263 case elfcpp::R_X86_64_PLT32:
4264 case elfcpp::R_X86_64_PLT32_BND:
4265 // If the symbol is fully resolved, this is just a PC32 reloc.
4266 // Otherwise we need a PLT entry.
4267 if (gsym->final_value_is_known())
4268 break;
4269 // If building a shared library, we can also skip the PLT entry
4270 // if the symbol is defined in the output file and is protected
4271 // or hidden.
4272 if (gsym->is_defined()
4273 && !gsym->is_from_dynobj()
4274 && !gsym->is_preemptible())
4275 break;
4276 target->make_plt_entry(symtab, layout, gsym);
4277 break;
4278
4279 case elfcpp::R_X86_64_GOTPC32:
4280 case elfcpp::R_X86_64_GOTOFF64:
4281 case elfcpp::R_X86_64_GOTPC64:
4282 case elfcpp::R_X86_64_PLTOFF64:
4283 // We need a GOT section.
4284 target->got_section(symtab, layout);
4285 // For PLTOFF64, we also need a PLT entry (but only if the
4286 // symbol is not fully resolved).
4287 if (r_type == elfcpp::R_X86_64_PLTOFF64
4288 && !gsym->final_value_is_known())
4289 target->make_plt_entry(symtab, layout, gsym);
4290 break;
4291
4292 case elfcpp::R_X86_64_COPY:
4293 case elfcpp::R_X86_64_GLOB_DAT:
4294 case elfcpp::R_X86_64_JUMP_SLOT:
4295 case elfcpp::R_X86_64_RELATIVE:
4296 case elfcpp::R_X86_64_IRELATIVE:
4297 // These are outstanding tls relocs, which are unexpected when linking
4298 case elfcpp::R_X86_64_TPOFF64:
4299 case elfcpp::R_X86_64_DTPMOD64:
4300 case elfcpp::R_X86_64_TLSDESC:
4301 gold_error(_("%s: unexpected reloc %u in object file"),
4302 object->name().c_str(), r_type);
4303 break;
4304
4305 // These are initial tls relocs, which are expected for global()
4306 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
4307 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
4308 case elfcpp::R_X86_64_TLSDESC_CALL:
4309 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
4310 case elfcpp::R_X86_64_DTPOFF32:
4311 case elfcpp::R_X86_64_DTPOFF64:
4312 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
4313 case elfcpp::R_X86_64_TPOFF32: // Local-exec
4314 {
4315 // For the Initial-Exec model, we can treat undef symbols as final
4316 // when building an executable.
4317 const bool is_final = (gsym->final_value_is_known() ||
4318 (r_type == elfcpp::R_X86_64_GOTTPOFF &&
4319 gsym->is_undefined() &&
4320 parameters->options().output_is_executable()));
4321 const tls::Tls_optimization optimized_type
4322 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
4323 switch (r_type)
4324 {
4325 case elfcpp::R_X86_64_TLSGD: // General-dynamic
4326 if (optimized_type == tls::TLSOPT_NONE)
4327 {
4328 // Create a pair of GOT entries for the module index and
4329 // dtv-relative offset.
4330 Output_data_got<64, false>* got
4331 = target->got_section(symtab, layout);
4332 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
4333 target->rela_dyn_section(layout),
4334 elfcpp::R_X86_64_DTPMOD64,
4335 elfcpp::R_X86_64_DTPOFF64);
4336 }
4337 else if (optimized_type == tls::TLSOPT_TO_IE)
4338 {
4339 // Create a GOT entry for the tp-relative offset.
4340 Output_data_got<64, false>* got
4341 = target->got_section(symtab, layout);
4342 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
4343 target->rela_dyn_section(layout),
4344 elfcpp::R_X86_64_TPOFF64);
4345 }
4346 else if (optimized_type != tls::TLSOPT_TO_LE)
4347 unsupported_reloc_global(object, r_type, gsym);
4348 break;
4349
4350 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
4351 target->define_tls_base_symbol(symtab, layout);
4352 if (optimized_type == tls::TLSOPT_NONE)
4353 {
4354 // Create reserved PLT and GOT entries for the resolver.
4355 target->reserve_tlsdesc_entries(symtab, layout);
4356
4357 // Create a double GOT entry with an R_X86_64_TLSDESC
4358 // reloc. The R_X86_64_TLSDESC reloc is resolved
4359 // lazily, so the GOT entry needs to be in an area in
4360 // .got.plt, not .got. Call got_section to make sure
4361 // the section has been created.
4362 target->got_section(symtab, layout);
4363 Output_data_got<64, false>* got = target->got_tlsdesc_section();
4364 Reloc_section* rt = target->rela_tlsdesc_section(layout);
4365 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
4366 elfcpp::R_X86_64_TLSDESC, 0);
4367 }
4368 else if (optimized_type == tls::TLSOPT_TO_IE)
4369 {
4370 // Create a GOT entry for the tp-relative offset.
4371 Output_data_got<64, false>* got
4372 = target->got_section(symtab, layout);
4373 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
4374 target->rela_dyn_section(layout),
4375 elfcpp::R_X86_64_TPOFF64);
4376 }
4377 else if (optimized_type != tls::TLSOPT_TO_LE)
4378 unsupported_reloc_global(object, r_type, gsym);
4379 break;
4380
4381 case elfcpp::R_X86_64_TLSDESC_CALL:
4382 break;
4383
4384 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
4385 if (optimized_type == tls::TLSOPT_NONE)
4386 {
4387 // Create a GOT entry for the module index.
4388 target->got_mod_index_entry(symtab, layout, object);
4389 }
4390 else if (optimized_type != tls::TLSOPT_TO_LE)
4391 unsupported_reloc_global(object, r_type, gsym);
4392 break;
4393
4394 case elfcpp::R_X86_64_DTPOFF32:
4395 case elfcpp::R_X86_64_DTPOFF64:
4396 break;
4397
4398 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
4399 layout->set_has_static_tls();
4400 if (optimized_type == tls::TLSOPT_NONE)
4401 {
4402 // Create a GOT entry for the tp-relative offset.
4403 Output_data_got<64, false>* got
4404 = target->got_section(symtab, layout);
4405 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
4406 target->rela_dyn_section(layout),
4407 elfcpp::R_X86_64_TPOFF64);
4408 }
4409 else if (optimized_type != tls::TLSOPT_TO_LE)
4410 unsupported_reloc_global(object, r_type, gsym);
4411 break;
4412
4413 case elfcpp::R_X86_64_TPOFF32: // Local-exec
4414 layout->set_has_static_tls();
4415 if (parameters->options().shared())
4416 unsupported_reloc_global(object, r_type, gsym);
4417 break;
4418
4419 default:
4420 gold_unreachable();
4421 }
4422 }
4423 break;
4424
4425 case elfcpp::R_X86_64_SIZE32:
4426 case elfcpp::R_X86_64_SIZE64:
4427 default:
4428 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
4429 object->name().c_str(), r_type,
4430 gsym->demangled_name().c_str());
4431 break;
4432 }
4433 }
4434
4435 template<int size>
4436 void
4437 Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab,
4438 Layout* layout,
4439 Sized_relobj_file<size, false>* object,
4440 unsigned int data_shndx,
4441 unsigned int sh_type,
4442 const unsigned char* prelocs,
4443 size_t reloc_count,
4444 Output_section* output_section,
4445 bool needs_special_offset_handling,
4446 size_t local_symbol_count,
4447 const unsigned char* plocal_symbols)
4448 {
4449 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
4450 Classify_reloc;
4451
4452 if (sh_type == elfcpp::SHT_REL)
4453 {
4454 return;
4455 }
4456
4457 gold::gc_process_relocs<size, false, Target_x86_64<size>, Scan,
4458 Classify_reloc>(
4459 symtab,
4460 layout,
4461 this,
4462 object,
4463 data_shndx,
4464 prelocs,
4465 reloc_count,
4466 output_section,
4467 needs_special_offset_handling,
4468 local_symbol_count,
4469 plocal_symbols);
4470
4471 }
4472 // Scan relocations for a section.
4473
4474 template<int size>
4475 void
4476 Target_x86_64<size>::scan_relocs(Symbol_table* symtab,
4477 Layout* layout,
4478 Sized_relobj_file<size, false>* object,
4479 unsigned int data_shndx,
4480 unsigned int sh_type,
4481 const unsigned char* prelocs,
4482 size_t reloc_count,
4483 Output_section* output_section,
4484 bool needs_special_offset_handling,
4485 size_t local_symbol_count,
4486 const unsigned char* plocal_symbols)
4487 {
4488 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
4489 Classify_reloc;
4490
4491 if (sh_type == elfcpp::SHT_REL)
4492 {
4493 gold_error(_("%s: unsupported REL reloc section"),
4494 object->name().c_str());
4495 return;
4496 }
4497
4498 gold::scan_relocs<size, false, Target_x86_64<size>, Scan, Classify_reloc>(
4499 symtab,
4500 layout,
4501 this,
4502 object,
4503 data_shndx,
4504 prelocs,
4505 reloc_count,
4506 output_section,
4507 needs_special_offset_handling,
4508 local_symbol_count,
4509 plocal_symbols);
4510 }
4511
4512 // Finalize the sections.
4513
4514 template<int size>
4515 void
4516 Target_x86_64<size>::do_finalize_sections(
4517 Layout* layout,
4518 const Input_objects*,
4519 Symbol_table* symtab)
4520 {
4521 const Reloc_section* rel_plt = (this->plt_ == NULL
4522 ? NULL
4523 : this->plt_->rela_plt());
4524 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
4525 this->rela_dyn_, true, false);
4526
4527 // Fill in some more dynamic tags.
4528 Output_data_dynamic* const odyn = layout->dynamic_data();
4529 if (odyn != NULL)
4530 {
4531 if (this->plt_ != NULL
4532 && this->plt_->output_section() != NULL
4533 && this->plt_->has_tlsdesc_entry())
4534 {
4535 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
4536 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
4537 this->got_->finalize_data_size();
4538 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
4539 this->plt_, plt_offset);
4540 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
4541 this->got_, got_offset);
4542 }
4543 }
4544
4545 // Emit any relocs we saved in an attempt to avoid generating COPY
4546 // relocs.
4547 if (this->copy_relocs_.any_saved_relocs())
4548 this->copy_relocs_.emit(this->rela_dyn_section(layout));
4549
4550 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
4551 // the .got.plt section.
4552 Symbol* sym = this->global_offset_table_;
4553 if (sym != NULL)
4554 {
4555 uint64_t data_size = this->got_plt_->current_data_size();
4556 symtab->get_sized_symbol<size>(sym)->set_symsize(data_size);
4557 }
4558
4559 if (parameters->doing_static_link()
4560 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
4561 {
4562 // If linking statically, make sure that the __rela_iplt symbols
4563 // were defined if necessary, even if we didn't create a PLT.
4564 static const Define_symbol_in_segment syms[] =
4565 {
4566 {
4567 "__rela_iplt_start", // name
4568 elfcpp::PT_LOAD, // segment_type
4569 elfcpp::PF_W, // segment_flags_set
4570 elfcpp::PF(0), // segment_flags_clear
4571 0, // value
4572 0, // size
4573 elfcpp::STT_NOTYPE, // type
4574 elfcpp::STB_GLOBAL, // binding
4575 elfcpp::STV_HIDDEN, // visibility
4576 0, // nonvis
4577 Symbol::SEGMENT_START, // offset_from_base
4578 true // only_if_ref
4579 },
4580 {
4581 "__rela_iplt_end", // name
4582 elfcpp::PT_LOAD, // segment_type
4583 elfcpp::PF_W, // segment_flags_set
4584 elfcpp::PF(0), // segment_flags_clear
4585 0, // value
4586 0, // size
4587 elfcpp::STT_NOTYPE, // type
4588 elfcpp::STB_GLOBAL, // binding
4589 elfcpp::STV_HIDDEN, // visibility
4590 0, // nonvis
4591 Symbol::SEGMENT_START, // offset_from_base
4592 true // only_if_ref
4593 }
4594 };
4595
4596 symtab->define_symbols(layout, 2, syms,
4597 layout->script_options()->saw_sections_clause());
4598 }
4599 }
4600
4601 // For x32, we need to handle PC-relative relocations using full 64-bit
4602 // arithmetic, so that we can detect relocation overflows properly.
4603 // This class overrides the pcrela32_check methods from the defaults in
4604 // Relocate_functions in reloc.h.
4605
4606 template<int size>
4607 class X86_64_relocate_functions : public Relocate_functions<size, false>
4608 {
4609 public:
4610 typedef Relocate_functions<size, false> Base;
4611
4612 // Do a simple PC relative relocation with the addend in the
4613 // relocation.
4614 static inline typename Base::Reloc_status
4615 pcrela32_check(unsigned char* view,
4616 typename elfcpp::Elf_types<64>::Elf_Addr value,
4617 typename elfcpp::Elf_types<64>::Elf_Swxword addend,
4618 typename elfcpp::Elf_types<64>::Elf_Addr address)
4619 {
4620 typedef typename elfcpp::Swap<32, false>::Valtype Valtype;
4621 Valtype* wv = reinterpret_cast<Valtype*>(view);
4622 value = value + addend - address;
4623 elfcpp::Swap<32, false>::writeval(wv, value);
4624 return (Bits<32>::has_overflow(value)
4625 ? Base::RELOC_OVERFLOW : Base::RELOC_OK);
4626 }
4627
4628 // Do a simple PC relative relocation with a Symbol_value with the
4629 // addend in the relocation.
4630 static inline typename Base::Reloc_status
4631 pcrela32_check(unsigned char* view,
4632 const Sized_relobj_file<size, false>* object,
4633 const Symbol_value<size>* psymval,
4634 typename elfcpp::Elf_types<64>::Elf_Swxword addend,
4635 typename elfcpp::Elf_types<64>::Elf_Addr address)
4636 {
4637 typedef typename elfcpp::Swap<32, false>::Valtype Valtype;
4638 Valtype* wv = reinterpret_cast<Valtype*>(view);
4639 typename elfcpp::Elf_types<64>::Elf_Addr value;
4640 if (addend >= 0)
4641 value = psymval->value(object, addend);
4642 else
4643 {
4644 // For negative addends, get the symbol value without
4645 // the addend, then add the addend using 64-bit arithmetic.
4646 value = psymval->value(object, 0);
4647 value += addend;
4648 }
4649 value -= address;
4650 elfcpp::Swap<32, false>::writeval(wv, value);
4651 return (Bits<32>::has_overflow(value)
4652 ? Base::RELOC_OVERFLOW : Base::RELOC_OK);
4653 }
4654 };
4655
4656 // Perform a relocation.
4657
4658 template<int size>
4659 inline bool
4660 Target_x86_64<size>::Relocate::relocate(
4661 const Relocate_info<size, false>* relinfo,
4662 unsigned int,
4663 Target_x86_64<size>* target,
4664 Output_section*,
4665 size_t relnum,
4666 const unsigned char* preloc,
4667 const Sized_symbol<size>* gsym,
4668 const Symbol_value<size>* psymval,
4669 unsigned char* view,
4670 typename elfcpp::Elf_types<size>::Elf_Addr address,
4671 section_size_type view_size)
4672 {
4673 typedef X86_64_relocate_functions<size> Reloc_funcs;
4674 const elfcpp::Rela<size, false> rela(preloc);
4675 unsigned int r_type = elfcpp::elf_r_type<size>(rela.get_r_info());
4676
4677 if (this->skip_call_tls_get_addr_)
4678 {
4679 if ((r_type != elfcpp::R_X86_64_PLT32
4680 && r_type != elfcpp::R_X86_64_GOTPCREL
4681 && r_type != elfcpp::R_X86_64_GOTPCRELX
4682 && r_type != elfcpp::R_X86_64_PLT32_BND
4683 && r_type != elfcpp::R_X86_64_PC32_BND
4684 && r_type != elfcpp::R_X86_64_PC32)
4685 || gsym == NULL
4686 || strcmp(gsym->name(), "__tls_get_addr") != 0)
4687 {
4688 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
4689 _("missing expected TLS relocation"));
4690 this->skip_call_tls_get_addr_ = false;
4691 }
4692 else
4693 {
4694 this->skip_call_tls_get_addr_ = false;
4695 return false;
4696 }
4697 }
4698
4699 if (view == NULL)
4700 return true;
4701
4702 const Sized_relobj_file<size, false>* object = relinfo->object;
4703
4704 // Pick the value to use for symbols defined in the PLT.
4705 Symbol_value<size> symval;
4706 if (gsym != NULL
4707 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
4708 {
4709 symval.set_output_value(target->plt_address_for_global(gsym));
4710 psymval = &symval;
4711 }
4712 else if (gsym == NULL && psymval->is_ifunc_symbol())
4713 {
4714 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
4715 if (object->local_has_plt_offset(r_sym))
4716 {
4717 symval.set_output_value(target->plt_address_for_local(object, r_sym));
4718 psymval = &symval;
4719 }
4720 }
4721
4722 const elfcpp::Elf_Xword addend = rela.get_r_addend();
4723
4724 // Get the GOT offset if needed.
4725 // The GOT pointer points to the end of the GOT section.
4726 // We need to subtract the size of the GOT section to get
4727 // the actual offset to use in the relocation.
4728 bool have_got_offset = false;
4729 // Since the actual offset is always negative, we use signed int to
4730 // support 64-bit GOT relocations.
4731 int got_offset = 0;
4732 switch (r_type)
4733 {
4734 case elfcpp::R_X86_64_GOT32:
4735 case elfcpp::R_X86_64_GOT64:
4736 case elfcpp::R_X86_64_GOTPLT64:
4737 case elfcpp::R_X86_64_GOTPCREL64:
4738 if (gsym != NULL)
4739 {
4740 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
4741 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
4742 }
4743 else
4744 {
4745 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
4746 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
4747 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
4748 - target->got_size());
4749 }
4750 have_got_offset = true;
4751 break;
4752
4753 default:
4754 break;
4755 }
4756
4757 typename Reloc_funcs::Reloc_status rstatus = Reloc_funcs::RELOC_OK;
4758
4759 switch (r_type)
4760 {
4761 case elfcpp::R_X86_64_NONE:
4762 case elfcpp::R_X86_64_GNU_VTINHERIT:
4763 case elfcpp::R_X86_64_GNU_VTENTRY:
4764 break;
4765
4766 case elfcpp::R_X86_64_64:
4767 Reloc_funcs::rela64(view, object, psymval, addend);
4768 break;
4769
4770 case elfcpp::R_X86_64_PC64:
4771 Reloc_funcs::pcrela64(view, object, psymval, addend,
4772 address);
4773 break;
4774
4775 case elfcpp::R_X86_64_32:
4776 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend,
4777 Reloc_funcs::CHECK_UNSIGNED);
4778 break;
4779
4780 case elfcpp::R_X86_64_32S:
4781 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend,
4782 Reloc_funcs::CHECK_SIGNED);
4783 break;
4784
4785 case elfcpp::R_X86_64_PC32:
4786 case elfcpp::R_X86_64_PC32_BND:
4787 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend,
4788 address);
4789 break;
4790
4791 case elfcpp::R_X86_64_16:
4792 Reloc_funcs::rela16(view, object, psymval, addend);
4793 break;
4794
4795 case elfcpp::R_X86_64_PC16:
4796 Reloc_funcs::pcrela16(view, object, psymval, addend, address);
4797 break;
4798
4799 case elfcpp::R_X86_64_8:
4800 Reloc_funcs::rela8(view, object, psymval, addend);
4801 break;
4802
4803 case elfcpp::R_X86_64_PC8:
4804 Reloc_funcs::pcrela8(view, object, psymval, addend, address);
4805 break;
4806
4807 case elfcpp::R_X86_64_PLT32:
4808 case elfcpp::R_X86_64_PLT32_BND:
4809 gold_assert(gsym == NULL
4810 || gsym->has_plt_offset()
4811 || gsym->final_value_is_known()
4812 || (gsym->is_defined()
4813 && !gsym->is_from_dynobj()
4814 && !gsym->is_preemptible()));
4815 // Note: while this code looks the same as for R_X86_64_PC32, it
4816 // behaves differently because psymval was set to point to
4817 // the PLT entry, rather than the symbol, in Scan::global().
4818 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend,
4819 address);
4820 break;
4821
4822 case elfcpp::R_X86_64_PLTOFF64:
4823 {
4824 gold_assert(gsym);
4825 gold_assert(gsym->has_plt_offset()
4826 || gsym->final_value_is_known());
4827 typename elfcpp::Elf_types<size>::Elf_Addr got_address;
4828 // This is the address of GLOBAL_OFFSET_TABLE.
4829 got_address = target->got_plt_section()->address();
4830 Reloc_funcs::rela64(view, object, psymval, addend - got_address);
4831 }
4832 break;
4833
4834 case elfcpp::R_X86_64_GOT32:
4835 gold_assert(have_got_offset);
4836 Reloc_funcs::rela32(view, got_offset, addend);
4837 break;
4838
4839 case elfcpp::R_X86_64_GOTPC32:
4840 {
4841 gold_assert(gsym);
4842 typename elfcpp::Elf_types<size>::Elf_Addr value;
4843 value = target->got_plt_section()->address();
4844 Reloc_funcs::pcrela32_check(view, value, addend, address);
4845 }
4846 break;
4847
4848 case elfcpp::R_X86_64_GOT64:
4849 case elfcpp::R_X86_64_GOTPLT64:
4850 // R_X86_64_GOTPLT64 is obsolete and treated the same as
4851 // GOT64.
4852 gold_assert(have_got_offset);
4853 Reloc_funcs::rela64(view, got_offset, addend);
4854 break;
4855
4856 case elfcpp::R_X86_64_GOTPC64:
4857 {
4858 gold_assert(gsym);
4859 typename elfcpp::Elf_types<size>::Elf_Addr value;
4860 value = target->got_plt_section()->address();
4861 Reloc_funcs::pcrela64(view, value, addend, address);
4862 }
4863 break;
4864
4865 case elfcpp::R_X86_64_GOTOFF64:
4866 {
4867 typename elfcpp::Elf_types<size>::Elf_Addr reladdr;
4868 reladdr = target->got_plt_section()->address();
4869 Reloc_funcs::pcrela64(view, object, psymval, addend, reladdr);
4870 }
4871 break;
4872
4873 case elfcpp::R_X86_64_GOTPCREL:
4874 case elfcpp::R_X86_64_GOTPCRELX:
4875 case elfcpp::R_X86_64_REX_GOTPCRELX:
4876 {
4877 // Convert
4878 // mov foo@GOTPCREL(%rip), %reg
4879 // to lea foo(%rip), %reg.
4880 // if possible.
4881 if (!parameters->incremental()
4882 && ((gsym == NULL
4883 && rela.get_r_offset() >= 2
4884 && view[-2] == 0x8b
4885 && !psymval->is_ifunc_symbol())
4886 || (gsym != NULL
4887 && rela.get_r_offset() >= 2
4888 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
4889 0, &view))))
4890 {
4891 view[-2] = 0x8d;
4892 Reloc_funcs::pcrela32(view, object, psymval, addend, address);
4893 }
4894 // Convert
4895 // callq *foo@GOTPCRELX(%rip) to
4896 // addr32 callq foo
4897 // and jmpq *foo@GOTPCRELX(%rip) to
4898 // jmpq foo
4899 // nop
4900 else if (!parameters->incremental()
4901 && gsym != NULL
4902 && rela.get_r_offset() >= 2
4903 && Target_x86_64<size>::can_convert_callq_to_direct(gsym,
4904 r_type,
4905 0, &view))
4906 {
4907 if (view[-1] == 0x15)
4908 {
4909 // Convert callq *foo@GOTPCRELX(%rip) to addr32 callq.
4910 // Opcode of addr32 is 0x67 and opcode of direct callq is 0xe8.
4911 view[-2] = 0x67;
4912 view[-1] = 0xe8;
4913 // Convert GOTPCRELX to 32-bit pc relative reloc.
4914 Reloc_funcs::pcrela32(view, object, psymval, addend, address);
4915 }
4916 else
4917 {
4918 // Convert jmpq *foo@GOTPCRELX(%rip) to
4919 // jmpq foo
4920 // nop
4921 // The opcode of direct jmpq is 0xe9.
4922 view[-2] = 0xe9;
4923 // The opcode of nop is 0x90.
4924 view[3] = 0x90;
4925 // Convert GOTPCRELX to 32-bit pc relative reloc. jmpq is rip
4926 // relative and since the instruction following the jmpq is now
4927 // the nop, offset the address by 1 byte. The start of the
4928 // relocation also moves ahead by 1 byte.
4929 Reloc_funcs::pcrela32(&view[-1], object, psymval, addend,
4930 address - 1);
4931 }
4932 }
4933 else
4934 {
4935 if (gsym != NULL)
4936 {
4937 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
4938 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
4939 - target->got_size());
4940 }
4941 else
4942 {
4943 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
4944 gold_assert(object->local_has_got_offset(r_sym,
4945 GOT_TYPE_STANDARD));
4946 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
4947 - target->got_size());
4948 }
4949 typename elfcpp::Elf_types<size>::Elf_Addr value;
4950 value = target->got_plt_section()->address() + got_offset;
4951 Reloc_funcs::pcrela32_check(view, value, addend, address);
4952 }
4953 }
4954 break;
4955
4956 case elfcpp::R_X86_64_GOTPCREL64:
4957 {
4958 gold_assert(have_got_offset);
4959 typename elfcpp::Elf_types<size>::Elf_Addr value;
4960 value = target->got_plt_section()->address() + got_offset;
4961 Reloc_funcs::pcrela64(view, value, addend, address);
4962 }
4963 break;
4964
4965 case elfcpp::R_X86_64_COPY:
4966 case elfcpp::R_X86_64_GLOB_DAT:
4967 case elfcpp::R_X86_64_JUMP_SLOT:
4968 case elfcpp::R_X86_64_RELATIVE:
4969 case elfcpp::R_X86_64_IRELATIVE:
4970 // These are outstanding tls relocs, which are unexpected when linking
4971 case elfcpp::R_X86_64_TPOFF64:
4972 case elfcpp::R_X86_64_DTPMOD64:
4973 case elfcpp::R_X86_64_TLSDESC:
4974 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
4975 _("unexpected reloc %u in object file"),
4976 r_type);
4977 break;
4978
4979 // These are initial tls relocs, which are expected when linking
4980 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
4981 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
4982 case elfcpp::R_X86_64_TLSDESC_CALL:
4983 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
4984 case elfcpp::R_X86_64_DTPOFF32:
4985 case elfcpp::R_X86_64_DTPOFF64:
4986 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
4987 case elfcpp::R_X86_64_TPOFF32: // Local-exec
4988 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
4989 view, address, view_size);
4990 break;
4991
4992 case elfcpp::R_X86_64_SIZE32:
4993 case elfcpp::R_X86_64_SIZE64:
4994 default:
4995 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
4996 _("unsupported reloc %u"),
4997 r_type);
4998 break;
4999 }
5000
5001 if (rstatus == Reloc_funcs::RELOC_OVERFLOW)
5002 {
5003 if (gsym == NULL)
5004 {
5005 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
5006 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5007 _("relocation overflow: "
5008 "reference to local symbol %u in %s"),
5009 r_sym, object->name().c_str());
5010 }
5011 else if (gsym->is_defined() && gsym->source() == Symbol::FROM_OBJECT)
5012 {
5013 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5014 _("relocation overflow: "
5015 "reference to '%s' defined in %s"),
5016 gsym->name(),
5017 gsym->object()->name().c_str());
5018 }
5019 else
5020 {
5021 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5022 _("relocation overflow: reference to '%s'"),
5023 gsym->name());
5024 }
5025 }
5026
5027 return true;
5028 }
5029
5030 // Perform a TLS relocation.
5031
5032 template<int size>
5033 inline void
5034 Target_x86_64<size>::Relocate::relocate_tls(
5035 const Relocate_info<size, false>* relinfo,
5036 Target_x86_64<size>* target,
5037 size_t relnum,
5038 const elfcpp::Rela<size, false>& rela,
5039 unsigned int r_type,
5040 const Sized_symbol<size>* gsym,
5041 const Symbol_value<size>* psymval,
5042 unsigned char* view,
5043 typename elfcpp::Elf_types<size>::Elf_Addr address,
5044 section_size_type view_size)
5045 {
5046 Output_segment* tls_segment = relinfo->layout->tls_segment();
5047
5048 const Sized_relobj_file<size, false>* object = relinfo->object;
5049 const elfcpp::Elf_Xword addend = rela.get_r_addend();
5050 elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr);
5051 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
5052
5053 typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0);
5054
5055 const bool is_final = (gsym == NULL
5056 ? !parameters->options().shared()
5057 : gsym->final_value_is_known());
5058 tls::Tls_optimization optimized_type
5059 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
5060 switch (r_type)
5061 {
5062 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
5063 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
5064 {
5065 // If this code sequence is used in a non-executable section,
5066 // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
5067 // on the assumption that it's being used by itself in a debug
5068 // section. Therefore, in the unlikely event that the code
5069 // sequence appears in a non-executable section, we simply
5070 // leave it unoptimized.
5071 optimized_type = tls::TLSOPT_NONE;
5072 }
5073 if (optimized_type == tls::TLSOPT_TO_LE)
5074 {
5075 if (tls_segment == NULL)
5076 {
5077 gold_assert(parameters->errors()->error_count() > 0
5078 || issue_undefined_symbol_error(gsym));
5079 return;
5080 }
5081 this->tls_gd_to_le(relinfo, relnum, tls_segment,
5082 rela, r_type, value, view,
5083 view_size);
5084 break;
5085 }
5086 else
5087 {
5088 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
5089 ? GOT_TYPE_TLS_OFFSET
5090 : GOT_TYPE_TLS_PAIR);
5091 unsigned int got_offset;
5092 if (gsym != NULL)
5093 {
5094 gold_assert(gsym->has_got_offset(got_type));
5095 got_offset = gsym->got_offset(got_type) - target->got_size();
5096 }
5097 else
5098 {
5099 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
5100 gold_assert(object->local_has_got_offset(r_sym, got_type));
5101 got_offset = (object->local_got_offset(r_sym, got_type)
5102 - target->got_size());
5103 }
5104 if (optimized_type == tls::TLSOPT_TO_IE)
5105 {
5106 value = target->got_plt_section()->address() + got_offset;
5107 this->tls_gd_to_ie(relinfo, relnum, rela, r_type,
5108 value, view, address, view_size);
5109 break;
5110 }
5111 else if (optimized_type == tls::TLSOPT_NONE)
5112 {
5113 // Relocate the field with the offset of the pair of GOT
5114 // entries.
5115 value = target->got_plt_section()->address() + got_offset;
5116 Relocate_functions<size, false>::pcrela32(view, value, addend,
5117 address);
5118 break;
5119 }
5120 }
5121 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5122 _("unsupported reloc %u"), r_type);
5123 break;
5124
5125 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
5126 case elfcpp::R_X86_64_TLSDESC_CALL:
5127 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
5128 {
5129 // See above comment for R_X86_64_TLSGD.
5130 optimized_type = tls::TLSOPT_NONE;
5131 }
5132 if (optimized_type == tls::TLSOPT_TO_LE)
5133 {
5134 if (tls_segment == NULL)
5135 {
5136 gold_assert(parameters->errors()->error_count() > 0
5137 || issue_undefined_symbol_error(gsym));
5138 return;
5139 }
5140 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
5141 rela, r_type, value, view,
5142 view_size);
5143 break;
5144 }
5145 else
5146 {
5147 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
5148 ? GOT_TYPE_TLS_OFFSET
5149 : GOT_TYPE_TLS_DESC);
5150 unsigned int got_offset = 0;
5151 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
5152 && optimized_type == tls::TLSOPT_NONE)
5153 {
5154 // We created GOT entries in the .got.tlsdesc portion of
5155 // the .got.plt section, but the offset stored in the
5156 // symbol is the offset within .got.tlsdesc.
5157 got_offset = (target->got_size()
5158 + target->got_plt_section()->data_size());
5159 }
5160 if (gsym != NULL)
5161 {
5162 gold_assert(gsym->has_got_offset(got_type));
5163 got_offset += gsym->got_offset(got_type) - target->got_size();
5164 }
5165 else
5166 {
5167 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
5168 gold_assert(object->local_has_got_offset(r_sym, got_type));
5169 got_offset += (object->local_got_offset(r_sym, got_type)
5170 - target->got_size());
5171 }
5172 if (optimized_type == tls::TLSOPT_TO_IE)
5173 {
5174 value = target->got_plt_section()->address() + got_offset;
5175 this->tls_desc_gd_to_ie(relinfo, relnum,
5176 rela, r_type, value, view, address,
5177 view_size);
5178 break;
5179 }
5180 else if (optimized_type == tls::TLSOPT_NONE)
5181 {
5182 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
5183 {
5184 // Relocate the field with the offset of the pair of GOT
5185 // entries.
5186 value = target->got_plt_section()->address() + got_offset;
5187 Relocate_functions<size, false>::pcrela32(view, value, addend,
5188 address);
5189 }
5190 break;
5191 }
5192 }
5193 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5194 _("unsupported reloc %u"), r_type);
5195 break;
5196
5197 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
5198 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
5199 {
5200 // See above comment for R_X86_64_TLSGD.
5201 optimized_type = tls::TLSOPT_NONE;
5202 }
5203 if (optimized_type == tls::TLSOPT_TO_LE)
5204 {
5205 if (tls_segment == NULL)
5206 {
5207 gold_assert(parameters->errors()->error_count() > 0
5208 || issue_undefined_symbol_error(gsym));
5209 return;
5210 }
5211 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
5212 value, view, view_size);
5213 break;
5214 }
5215 else if (optimized_type == tls::TLSOPT_NONE)
5216 {
5217 // Relocate the field with the offset of the GOT entry for
5218 // the module index.
5219 unsigned int got_offset;
5220 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
5221 - target->got_size());
5222 value = target->got_plt_section()->address() + got_offset;
5223 Relocate_functions<size, false>::pcrela32(view, value, addend,
5224 address);
5225 break;
5226 }
5227 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5228 _("unsupported reloc %u"), r_type);
5229 break;
5230
5231 case elfcpp::R_X86_64_DTPOFF32:
5232 // This relocation type is used in debugging information.
5233 // In that case we need to not optimize the value. If the
5234 // section is not executable, then we assume we should not
5235 // optimize this reloc. See comments above for R_X86_64_TLSGD,
5236 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
5237 // R_X86_64_TLSLD.
5238 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
5239 {
5240 if (tls_segment == NULL)
5241 {
5242 gold_assert(parameters->errors()->error_count() > 0
5243 || issue_undefined_symbol_error(gsym));
5244 return;
5245 }
5246 value -= tls_segment->memsz();
5247 }
5248 Relocate_functions<size, false>::rela32(view, value, addend);
5249 break;
5250
5251 case elfcpp::R_X86_64_DTPOFF64:
5252 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
5253 if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
5254 {
5255 if (tls_segment == NULL)
5256 {
5257 gold_assert(parameters->errors()->error_count() > 0
5258 || issue_undefined_symbol_error(gsym));
5259 return;
5260 }
5261 value -= tls_segment->memsz();
5262 }
5263 Relocate_functions<size, false>::rela64(view, value, addend);
5264 break;
5265
5266 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
5267 if (gsym != NULL
5268 && gsym->is_undefined()
5269 && parameters->options().output_is_executable())
5270 {
5271 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
5272 NULL, rela,
5273 r_type, value, view,
5274 view_size);
5275 break;
5276 }
5277 else if (optimized_type == tls::TLSOPT_TO_LE)
5278 {
5279 if (tls_segment == NULL)
5280 {
5281 gold_assert(parameters->errors()->error_count() > 0
5282 || issue_undefined_symbol_error(gsym));
5283 return;
5284 }
5285 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
5286 tls_segment, rela,
5287 r_type, value, view,
5288 view_size);
5289 break;
5290 }
5291 else if (optimized_type == tls::TLSOPT_NONE)
5292 {
5293 // Relocate the field with the offset of the GOT entry for
5294 // the tp-relative offset of the symbol.
5295 unsigned int got_offset;
5296 if (gsym != NULL)
5297 {
5298 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
5299 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
5300 - target->got_size());
5301 }
5302 else
5303 {
5304 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
5305 gold_assert(object->local_has_got_offset(r_sym,
5306 GOT_TYPE_TLS_OFFSET));
5307 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
5308 - target->got_size());
5309 }
5310 value = target->got_plt_section()->address() + got_offset;
5311 Relocate_functions<size, false>::pcrela32(view, value, addend,
5312 address);
5313 break;
5314 }
5315 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
5316 _("unsupported reloc type %u"),
5317 r_type);
5318 break;
5319
5320 case elfcpp::R_X86_64_TPOFF32: // Local-exec
5321 if (tls_segment == NULL)
5322 {
5323 gold_assert(parameters->errors()->error_count() > 0
5324 || issue_undefined_symbol_error(gsym));
5325 return;
5326 }
5327 value -= tls_segment->memsz();
5328 Relocate_functions<size, false>::rela32(view, value, addend);
5329 break;
5330 }
5331 }
5332
5333 // Do a relocation in which we convert a TLS General-Dynamic to an
5334 // Initial-Exec.
5335
5336 template<int size>
5337 inline void
5338 Target_x86_64<size>::Relocate::tls_gd_to_ie(
5339 const Relocate_info<size, false>* relinfo,
5340 size_t relnum,
5341 const elfcpp::Rela<size, false>& rela,
5342 unsigned int,
5343 typename elfcpp::Elf_types<size>::Elf_Addr value,
5344 unsigned char* view,
5345 typename elfcpp::Elf_types<size>::Elf_Addr address,
5346 section_size_type view_size)
5347 {
5348 // For SIZE == 64:
5349 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
5350 // .word 0x6666; rex64; call __tls_get_addr@PLT
5351 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
5352 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
5353 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
5354 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
5355 // For SIZE == 32:
5356 // leaq foo@tlsgd(%rip),%rdi;
5357 // .word 0x6666; rex64; call __tls_get_addr@PLT
5358 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
5359 // leaq foo@tlsgd(%rip),%rdi;
5360 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
5361 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
5362
5363 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
5364 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5365 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0
5366 || memcmp(view + 4, "\x66\x48\xff", 3) == 0));
5367
5368 if (size == 64)
5369 {
5370 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
5371 -4);
5372 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5373 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
5374 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
5375 16);
5376 }
5377 else
5378 {
5379 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
5380 -3);
5381 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5382 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
5383 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
5384 15);
5385 }
5386
5387 const elfcpp::Elf_Xword addend = rela.get_r_addend();
5388 Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8,
5389 address);
5390
5391 // The next reloc should be a PLT32 reloc against __tls_get_addr.
5392 // We can skip it.
5393 this->skip_call_tls_get_addr_ = true;
5394 }
5395
5396 // Do a relocation in which we convert a TLS General-Dynamic to a
5397 // Local-Exec.
5398
5399 template<int size>
5400 inline void
5401 Target_x86_64<size>::Relocate::tls_gd_to_le(
5402 const Relocate_info<size, false>* relinfo,
5403 size_t relnum,
5404 Output_segment* tls_segment,
5405 const elfcpp::Rela<size, false>& rela,
5406 unsigned int,
5407 typename elfcpp::Elf_types<size>::Elf_Addr value,
5408 unsigned char* view,
5409 section_size_type view_size)
5410 {
5411 // For SIZE == 64:
5412 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
5413 // .word 0x6666; rex64; call __tls_get_addr@PLT
5414 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
5415 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
5416 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
5417 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
5418 // For SIZE == 32:
5419 // leaq foo@tlsgd(%rip),%rdi;
5420 // .word 0x6666; rex64; call __tls_get_addr@PLT
5421 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
5422 // leaq foo@tlsgd(%rip),%rdi;
5423 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip)
5424 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
5425
5426 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
5427 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5428 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0
5429 || memcmp(view + 4, "\x66\x48\xff", 3) == 0));
5430
5431 if (size == 64)
5432 {
5433 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
5434 -4);
5435 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5436 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
5437 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
5438 16);
5439 }
5440 else
5441 {
5442 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
5443 -3);
5444 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5445 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
5446
5447 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
5448 15);
5449 }
5450
5451 value -= tls_segment->memsz();
5452 Relocate_functions<size, false>::rela32(view + 8, value, 0);
5453
5454 // The next reloc should be a PLT32 reloc against __tls_get_addr.
5455 // We can skip it.
5456 this->skip_call_tls_get_addr_ = true;
5457 }
5458
5459 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
5460
5461 template<int size>
5462 inline void
5463 Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
5464 const Relocate_info<size, false>* relinfo,
5465 size_t relnum,
5466 const elfcpp::Rela<size, false>& rela,
5467 unsigned int r_type,
5468 typename elfcpp::Elf_types<size>::Elf_Addr value,
5469 unsigned char* view,
5470 typename elfcpp::Elf_types<size>::Elf_Addr address,
5471 section_size_type view_size)
5472 {
5473 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
5474 {
5475 // LP64: leaq foo@tlsdesc(%rip), %rax
5476 // ==> movq foo@gottpoff(%rip), %rax
5477 // X32: rex leal foo@tlsdesc(%rip), %eax
5478 // ==> rex movl foo@gottpoff(%rip), %eax
5479 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
5480 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
5481 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5482 (((view[-3] & 0xfb) == 0x48
5483 || (size == 32 && (view[-3] & 0xfb) == 0x40))
5484 && view[-2] == 0x8d
5485 && (view[-1] & 0xc7) == 0x05));
5486 view[-2] = 0x8b;
5487 const elfcpp::Elf_Xword addend = rela.get_r_addend();
5488 Relocate_functions<size, false>::pcrela32(view, value, addend, address);
5489 }
5490 else
5491 {
5492 // LP64: call *foo@tlscall(%rax)
5493 // ==> xchg %ax, %ax
5494 // X32: call *foo@tlscall(%eax)
5495 // ==> nopl (%rax)
5496 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
5497 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
5498 int prefix = 0;
5499 if (size == 32 && view[0] == 0x67)
5500 {
5501 tls::check_range(relinfo, relnum, rela.get_r_offset(),
5502 view_size, 3);
5503 prefix = 1;
5504 }
5505 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5506 view[prefix] == 0xff && view[prefix + 1] == 0x10);
5507 if (prefix)
5508 {
5509 view[0] = 0x0f;
5510 view[1] = 0x1f;
5511 view[2] = 0x00;
5512 }
5513 else
5514 {
5515 view[0] = 0x66;
5516 view[1] = 0x90;
5517 }
5518 }
5519 }
5520
5521 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
5522
5523 template<int size>
5524 inline void
5525 Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
5526 const Relocate_info<size, false>* relinfo,
5527 size_t relnum,
5528 Output_segment* tls_segment,
5529 const elfcpp::Rela<size, false>& rela,
5530 unsigned int r_type,
5531 typename elfcpp::Elf_types<size>::Elf_Addr value,
5532 unsigned char* view,
5533 section_size_type view_size)
5534 {
5535 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
5536 {
5537 // LP64: leaq foo@tlsdesc(%rip), %rax
5538 // ==> movq foo@tpoff, %rax
5539 // X32: rex leal foo@tlsdesc(%rip), %eax
5540 // ==> rex movl foo@tpoff, %eax
5541 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
5542 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
5543 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5544 (((view[-3] & 0xfb) == 0x48
5545 || (size == 32 && (view[-3] & 0xfb) == 0x40))
5546 && view[-2] == 0x8d
5547 && (view[-1] & 0xc7) == 0x05));
5548 view[-3] = (view[-3] & 0x48) | ((view[-3] >> 2) & 1);
5549 view[-2] = 0xc7;
5550 view[-1] = 0xc0 | ((view[-1] >> 3) & 7);
5551 value -= tls_segment->memsz();
5552 Relocate_functions<size, false>::rela32(view, value, 0);
5553 }
5554 else
5555 {
5556 // LP64: call *foo@tlscall(%rax)
5557 // ==> xchg %ax, %ax
5558 // X32: call *foo@tlscall(%eax)
5559 // ==> nopl (%rax)
5560 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
5561 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
5562 int prefix = 0;
5563 if (size == 32 && view[0] == 0x67)
5564 {
5565 tls::check_range(relinfo, relnum, rela.get_r_offset(),
5566 view_size, 3);
5567 prefix = 1;
5568 }
5569 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5570 view[prefix] == 0xff && view[prefix + 1] == 0x10);
5571 if (prefix)
5572 {
5573 view[0] = 0x0f;
5574 view[1] = 0x1f;
5575 view[2] = 0x00;
5576 }
5577 else
5578 {
5579 view[0] = 0x66;
5580 view[1] = 0x90;
5581 }
5582 }
5583 }
5584
5585 template<int size>
5586 inline void
5587 Target_x86_64<size>::Relocate::tls_ld_to_le(
5588 const Relocate_info<size, false>* relinfo,
5589 size_t relnum,
5590 Output_segment*,
5591 const elfcpp::Rela<size, false>& rela,
5592 unsigned int,
5593 typename elfcpp::Elf_types<size>::Elf_Addr,
5594 unsigned char* view,
5595 section_size_type view_size)
5596 {
5597 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
5598 // For SIZE == 64:
5599 // ... leq foo@dtpoff(%rax),%reg
5600 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
5601 // For SIZE == 32:
5602 // ... leq foo@dtpoff(%rax),%reg
5603 // ==> nopl 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx
5604 // leaq foo@tlsld(%rip),%rdi; call *__tls_get_addr@GOTPCREL(%rip)
5605 // For SIZE == 64:
5606 // ... leq foo@dtpoff(%rax),%reg
5607 // ==> .word 0x6666; .byte 0x6666; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
5608 // For SIZE == 32:
5609 // ... leq foo@dtpoff(%rax),%reg
5610 // ==> nopw 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx
5611
5612 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
5613 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
5614
5615 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5616 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
5617
5618 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
5619 view[4] == 0xe8 || view[4] == 0xff);
5620
5621 if (view[4] == 0xe8)
5622 {
5623 if (size == 64)
5624 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
5625 else
5626 memcpy(view - 3, "\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 12);
5627 }
5628 else
5629 {
5630 if (size == 64)
5631 memcpy(view - 3, "\x66\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0",
5632 13);
5633 else
5634 memcpy(view - 3, "\x66\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0",
5635 13);
5636 }
5637
5638 // The next reloc should be a PLT32 reloc against __tls_get_addr.
5639 // We can skip it.
5640 this->skip_call_tls_get_addr_ = true;
5641 }
5642
5643 // Do a relocation in which we convert a TLS Initial-Exec to a
5644 // Local-Exec.
5645
5646 template<int size>
5647 inline void
5648 Target_x86_64<size>::Relocate::tls_ie_to_le(
5649 const Relocate_info<size, false>* relinfo,
5650 size_t relnum,
5651 Output_segment* tls_segment,
5652 const elfcpp::Rela<size, false>& rela,
5653 unsigned int,
5654 typename elfcpp::Elf_types<size>::Elf_Addr value,
5655 unsigned char* view,
5656 section_size_type view_size)
5657 {
5658 // We need to examine the opcodes to figure out which instruction we
5659 // are looking at.
5660
5661 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
5662 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
5663
5664 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
5665 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
5666
5667 unsigned char op1 = view[-3];
5668 unsigned char op2 = view[-2];
5669 unsigned char op3 = view[-1];
5670 unsigned char reg = op3 >> 3;
5671
5672 if (op2 == 0x8b)
5673 {
5674 // movq
5675 if (op1 == 0x4c)
5676 view[-3] = 0x49;
5677 else if (size == 32 && op1 == 0x44)
5678 view[-3] = 0x41;
5679 view[-2] = 0xc7;
5680 view[-1] = 0xc0 | reg;
5681 }
5682 else if (reg == 4)
5683 {
5684 // Special handling for %rsp.
5685 if (op1 == 0x4c)
5686 view[-3] = 0x49;
5687 else if (size == 32 && op1 == 0x44)
5688 view[-3] = 0x41;
5689 view[-2] = 0x81;
5690 view[-1] = 0xc0 | reg;
5691 }
5692 else
5693 {
5694 // addq
5695 if (op1 == 0x4c)
5696 view[-3] = 0x4d;
5697 else if (size == 32 && op1 == 0x44)
5698 view[-3] = 0x45;
5699 view[-2] = 0x8d;
5700 view[-1] = 0x80 | reg | (reg << 3);
5701 }
5702
5703 if (tls_segment != NULL)
5704 value -= tls_segment->memsz();
5705 Relocate_functions<size, false>::rela32(view, value, 0);
5706 }
5707
5708 // Relocate section data.
5709
5710 template<int size>
5711 void
5712 Target_x86_64<size>::relocate_section(
5713 const Relocate_info<size, false>* relinfo,
5714 unsigned int sh_type,
5715 const unsigned char* prelocs,
5716 size_t reloc_count,
5717 Output_section* output_section,
5718 bool needs_special_offset_handling,
5719 unsigned char* view,
5720 typename elfcpp::Elf_types<size>::Elf_Addr address,
5721 section_size_type view_size,
5722 const Reloc_symbol_changes* reloc_symbol_changes)
5723 {
5724 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
5725 Classify_reloc;
5726
5727 gold_assert(sh_type == elfcpp::SHT_RELA);
5728
5729 gold::relocate_section<size, false, Target_x86_64<size>, Relocate,
5730 gold::Default_comdat_behavior, Classify_reloc>(
5731 relinfo,
5732 this,
5733 prelocs,
5734 reloc_count,
5735 output_section,
5736 needs_special_offset_handling,
5737 view,
5738 address,
5739 view_size,
5740 reloc_symbol_changes);
5741 }
5742
5743 // Apply an incremental relocation. Incremental relocations always refer
5744 // to global symbols.
5745
5746 template<int size>
5747 void
5748 Target_x86_64<size>::apply_relocation(
5749 const Relocate_info<size, false>* relinfo,
5750 typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
5751 unsigned int r_type,
5752 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
5753 const Symbol* gsym,
5754 unsigned char* view,
5755 typename elfcpp::Elf_types<size>::Elf_Addr address,
5756 section_size_type view_size)
5757 {
5758 gold::apply_relocation<size, false, Target_x86_64<size>,
5759 typename Target_x86_64<size>::Relocate>(
5760 relinfo,
5761 this,
5762 r_offset,
5763 r_type,
5764 r_addend,
5765 gsym,
5766 view,
5767 address,
5768 view_size);
5769 }
5770
5771 // Scan the relocs during a relocatable link.
5772
5773 template<int size>
5774 void
5775 Target_x86_64<size>::scan_relocatable_relocs(
5776 Symbol_table* symtab,
5777 Layout* layout,
5778 Sized_relobj_file<size, false>* object,
5779 unsigned int data_shndx,
5780 unsigned int sh_type,
5781 const unsigned char* prelocs,
5782 size_t reloc_count,
5783 Output_section* output_section,
5784 bool needs_special_offset_handling,
5785 size_t local_symbol_count,
5786 const unsigned char* plocal_symbols,
5787 Relocatable_relocs* rr)
5788 {
5789 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
5790 Classify_reloc;
5791 typedef gold::Default_scan_relocatable_relocs<Classify_reloc>
5792 Scan_relocatable_relocs;
5793
5794 gold_assert(sh_type == elfcpp::SHT_RELA);
5795
5796 gold::scan_relocatable_relocs<size, false, Scan_relocatable_relocs>(
5797 symtab,
5798 layout,
5799 object,
5800 data_shndx,
5801 prelocs,
5802 reloc_count,
5803 output_section,
5804 needs_special_offset_handling,
5805 local_symbol_count,
5806 plocal_symbols,
5807 rr);
5808 }
5809
5810 // Scan the relocs for --emit-relocs.
5811
5812 template<int size>
5813 void
5814 Target_x86_64<size>::emit_relocs_scan(
5815 Symbol_table* symtab,
5816 Layout* layout,
5817 Sized_relobj_file<size, false>* object,
5818 unsigned int data_shndx,
5819 unsigned int sh_type,
5820 const unsigned char* prelocs,
5821 size_t reloc_count,
5822 Output_section* output_section,
5823 bool needs_special_offset_handling,
5824 size_t local_symbol_count,
5825 const unsigned char* plocal_syms,
5826 Relocatable_relocs* rr)
5827 {
5828 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
5829 Classify_reloc;
5830 typedef gold::Default_emit_relocs_strategy<Classify_reloc>
5831 Emit_relocs_strategy;
5832
5833 gold_assert(sh_type == elfcpp::SHT_RELA);
5834
5835 gold::scan_relocatable_relocs<size, false, Emit_relocs_strategy>(
5836 symtab,
5837 layout,
5838 object,
5839 data_shndx,
5840 prelocs,
5841 reloc_count,
5842 output_section,
5843 needs_special_offset_handling,
5844 local_symbol_count,
5845 plocal_syms,
5846 rr);
5847 }
5848
5849 // Relocate a section during a relocatable link.
5850
5851 template<int size>
5852 void
5853 Target_x86_64<size>::relocate_relocs(
5854 const Relocate_info<size, false>* relinfo,
5855 unsigned int sh_type,
5856 const unsigned char* prelocs,
5857 size_t reloc_count,
5858 Output_section* output_section,
5859 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
5860 unsigned char* view,
5861 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
5862 section_size_type view_size,
5863 unsigned char* reloc_view,
5864 section_size_type reloc_view_size)
5865 {
5866 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false>
5867 Classify_reloc;
5868
5869 gold_assert(sh_type == elfcpp::SHT_RELA);
5870
5871 gold::relocate_relocs<size, false, Classify_reloc>(
5872 relinfo,
5873 prelocs,
5874 reloc_count,
5875 output_section,
5876 offset_in_output_section,
5877 view,
5878 view_address,
5879 view_size,
5880 reloc_view,
5881 reloc_view_size);
5882 }
5883
5884 // Return the value to use for a dynamic which requires special
5885 // treatment. This is how we support equality comparisons of function
5886 // pointers across shared library boundaries, as described in the
5887 // processor specific ABI supplement.
5888
5889 template<int size>
5890 uint64_t
5891 Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const
5892 {
5893 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
5894 return this->plt_address_for_global(gsym);
5895 }
5896
5897 // Return a string used to fill a code section with nops to take up
5898 // the specified length.
5899
5900 template<int size>
5901 std::string
5902 Target_x86_64<size>::do_code_fill(section_size_type length) const
5903 {
5904 if (length >= 16)
5905 {
5906 // Build a jmpq instruction to skip over the bytes.
5907 unsigned char jmp[5];
5908 jmp[0] = 0xe9;
5909 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
5910 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
5911 + std::string(length - 5, static_cast<char>(0x90)));
5912 }
5913
5914 // Nop sequences of various lengths.
5915 const char nop1[1] = { '\x90' }; // nop
5916 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
5917 const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax)
5918 const char nop4[4] = { '\x0f', '\x1f', '\x40', // nop 0(%rax)
5919 '\x00'};
5920 const char nop5[5] = { '\x0f', '\x1f', '\x44', // nop 0(%rax,%rax,1)
5921 '\x00', '\x00' };
5922 const char nop6[6] = { '\x66', '\x0f', '\x1f', // nopw 0(%rax,%rax,1)
5923 '\x44', '\x00', '\x00' };
5924 const char nop7[7] = { '\x0f', '\x1f', '\x80', // nopl 0L(%rax)
5925 '\x00', '\x00', '\x00',
5926 '\x00' };
5927 const char nop8[8] = { '\x0f', '\x1f', '\x84', // nopl 0L(%rax,%rax,1)
5928 '\x00', '\x00', '\x00',
5929 '\x00', '\x00' };
5930 const char nop9[9] = { '\x66', '\x0f', '\x1f', // nopw 0L(%rax,%rax,1)
5931 '\x84', '\x00', '\x00',
5932 '\x00', '\x00', '\x00' };
5933 const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
5934 '\x1f', '\x84', '\x00',
5935 '\x00', '\x00', '\x00',
5936 '\x00' };
5937 const char nop11[11] = { '\x66', '\x66', '\x2e', // data16
5938 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
5939 '\x00', '\x00', '\x00',
5940 '\x00', '\x00' };
5941 const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16
5942 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
5943 '\x84', '\x00', '\x00',
5944 '\x00', '\x00', '\x00' };
5945 const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16
5946 '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
5947 '\x1f', '\x84', '\x00',
5948 '\x00', '\x00', '\x00',
5949 '\x00' };
5950 const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16
5951 '\x66', '\x66', '\x2e', // data16
5952 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
5953 '\x00', '\x00', '\x00',
5954 '\x00', '\x00' };
5955 const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16
5956 '\x66', '\x66', '\x66', // data16; data16
5957 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
5958 '\x84', '\x00', '\x00',
5959 '\x00', '\x00', '\x00' };
5960
5961 const char* nops[16] = {
5962 NULL,
5963 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
5964 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
5965 };
5966
5967 return std::string(nops[length], length);
5968 }
5969
5970 // Return the addend to use for a target specific relocation. The
5971 // only target specific relocation is R_X86_64_TLSDESC for a local
5972 // symbol. We want to set the addend is the offset of the local
5973 // symbol in the TLS segment.
5974
5975 template<int size>
5976 uint64_t
5977 Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type,
5978 uint64_t) const
5979 {
5980 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
5981 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
5982 gold_assert(intarg < this->tlsdesc_reloc_info_.size());
5983 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
5984 const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym);
5985 gold_assert(psymval->is_tls_symbol());
5986 // The value of a TLS symbol is the offset in the TLS segment.
5987 return psymval->value(ti.object, 0);
5988 }
5989
5990 // Return the value to use for the base of a DW_EH_PE_datarel offset
5991 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
5992 // assembler can not write out the difference between two labels in
5993 // different sections, so instead of using a pc-relative value they
5994 // use an offset from the GOT.
5995
5996 template<int size>
5997 uint64_t
5998 Target_x86_64<size>::do_ehframe_datarel_base() const
5999 {
6000 gold_assert(this->global_offset_table_ != NULL);
6001 Symbol* sym = this->global_offset_table_;
6002 Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym);
6003 return ssym->value();
6004 }
6005
6006 // FNOFFSET in section SHNDX in OBJECT is the start of a function
6007 // compiled with -fsplit-stack. The function calls non-split-stack
6008 // code. We have to change the function so that it always ensures
6009 // that it has enough stack space to run some random function.
6010
6011 static const unsigned char cmp_insn_32[] = { 0x64, 0x3b, 0x24, 0x25 };
6012 static const unsigned char lea_r10_insn_32[] = { 0x44, 0x8d, 0x94, 0x24 };
6013 static const unsigned char lea_r11_insn_32[] = { 0x44, 0x8d, 0x9c, 0x24 };
6014
6015 static const unsigned char cmp_insn_64[] = { 0x64, 0x48, 0x3b, 0x24, 0x25 };
6016 static const unsigned char lea_r10_insn_64[] = { 0x4c, 0x8d, 0x94, 0x24 };
6017 static const unsigned char lea_r11_insn_64[] = { 0x4c, 0x8d, 0x9c, 0x24 };
6018
6019 template<int size>
6020 void
6021 Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx,
6022 section_offset_type fnoffset,
6023 section_size_type fnsize,
6024 const unsigned char*,
6025 size_t,
6026 unsigned char* view,
6027 section_size_type view_size,
6028 std::string* from,
6029 std::string* to) const
6030 {
6031 const char* const cmp_insn = reinterpret_cast<const char*>
6032 (size == 32 ? cmp_insn_32 : cmp_insn_64);
6033 const char* const lea_r10_insn = reinterpret_cast<const char*>
6034 (size == 32 ? lea_r10_insn_32 : lea_r10_insn_64);
6035 const char* const lea_r11_insn = reinterpret_cast<const char*>
6036 (size == 32 ? lea_r11_insn_32 : lea_r11_insn_64);
6037
6038 const size_t cmp_insn_len =
6039 (size == 32 ? sizeof(cmp_insn_32) : sizeof(cmp_insn_64));
6040 const size_t lea_r10_insn_len =
6041 (size == 32 ? sizeof(lea_r10_insn_32) : sizeof(lea_r10_insn_64));
6042 const size_t lea_r11_insn_len =
6043 (size == 32 ? sizeof(lea_r11_insn_32) : sizeof(lea_r11_insn_64));
6044 const size_t nop_len = (size == 32 ? 7 : 8);
6045
6046 // The function starts with a comparison of the stack pointer and a
6047 // field in the TCB. This is followed by a jump.
6048
6049 // cmp %fs:NN,%rsp
6050 if (this->match_view(view, view_size, fnoffset, cmp_insn, cmp_insn_len)
6051 && fnsize > nop_len + 1)
6052 {
6053 // We will call __morestack if the carry flag is set after this
6054 // comparison. We turn the comparison into an stc instruction
6055 // and some nops.
6056 view[fnoffset] = '\xf9';
6057 this->set_view_to_nop(view, view_size, fnoffset + 1, nop_len);
6058 }
6059 // lea NN(%rsp),%r10
6060 // lea NN(%rsp),%r11
6061 else if ((this->match_view(view, view_size, fnoffset,
6062 lea_r10_insn, lea_r10_insn_len)
6063 || this->match_view(view, view_size, fnoffset,
6064 lea_r11_insn, lea_r11_insn_len))
6065 && fnsize > 8)
6066 {
6067 // This is loading an offset from the stack pointer for a
6068 // comparison. The offset is negative, so we decrease the
6069 // offset by the amount of space we need for the stack. This
6070 // means we will avoid calling __morestack if there happens to
6071 // be plenty of space on the stack already.
6072 unsigned char* pval = view + fnoffset + 4;
6073 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
6074 val -= parameters->options().split_stack_adjust_size();
6075 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
6076 }
6077 else
6078 {
6079 if (!object->has_no_split_stack())
6080 object->error(_("failed to match split-stack sequence at "
6081 "section %u offset %0zx"),
6082 shndx, static_cast<size_t>(fnoffset));
6083 return;
6084 }
6085
6086 // We have to change the function so that it calls
6087 // __morestack_non_split instead of __morestack. The former will
6088 // allocate additional stack space.
6089 *from = "__morestack";
6090 *to = "__morestack_non_split";
6091 }
6092
6093 // The selector for x86_64 object files. Note this is never instantiated
6094 // directly. It's only used in Target_selector_x86_64_nacl, below.
6095
6096 template<int size>
6097 class Target_selector_x86_64 : public Target_selector_freebsd
6098 {
6099 public:
6100 Target_selector_x86_64()
6101 : Target_selector_freebsd(elfcpp::EM_X86_64, size, false,
6102 (size == 64
6103 ? "elf64-x86-64" : "elf32-x86-64"),
6104 (size == 64
6105 ? "elf64-x86-64-freebsd"
6106 : "elf32-x86-64-freebsd"),
6107 (size == 64 ? "elf_x86_64" : "elf32_x86_64"))
6108 { }
6109
6110 Target*
6111 do_instantiate_target()
6112 { return new Target_x86_64<size>(); }
6113
6114 };
6115
6116 // NaCl variant. It uses different PLT contents.
6117
6118 template<int size>
6119 class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size>
6120 {
6121 public:
6122 Output_data_plt_x86_64_nacl(Layout* layout,
6123 Output_data_got<64, false>* got,
6124 Output_data_got_plt_x86_64* got_plt,
6125 Output_data_space* got_irelative)
6126 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
6127 got, got_plt, got_irelative)
6128 { }
6129
6130 Output_data_plt_x86_64_nacl(Layout* layout,
6131 Output_data_got<64, false>* got,
6132 Output_data_got_plt_x86_64* got_plt,
6133 Output_data_space* got_irelative,
6134 unsigned int plt_count)
6135 : Output_data_plt_x86_64<size>(layout, plt_entry_size,
6136 got, got_plt, got_irelative,
6137 plt_count)
6138 { }
6139
6140 protected:
6141 virtual unsigned int
6142 do_get_plt_entry_size() const
6143 { return plt_entry_size; }
6144
6145 virtual void
6146 do_add_eh_frame(Layout* layout)
6147 {
6148 layout->add_eh_frame_for_plt(this,
6149 this->plt_eh_frame_cie,
6150 this->plt_eh_frame_cie_size,
6151 plt_eh_frame_fde,
6152 plt_eh_frame_fde_size);
6153 }
6154
6155 virtual void
6156 do_fill_first_plt_entry(unsigned char* pov,
6157 typename elfcpp::Elf_types<size>::Elf_Addr got_addr,
6158 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr);
6159
6160 virtual unsigned int
6161 do_fill_plt_entry(unsigned char* pov,
6162 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
6163 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
6164 unsigned int got_offset,
6165 unsigned int plt_offset,
6166 unsigned int plt_index);
6167
6168 virtual void
6169 do_fill_tlsdesc_entry(unsigned char* pov,
6170 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
6171 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
6172 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
6173 unsigned int tlsdesc_got_offset,
6174 unsigned int plt_offset);
6175
6176 private:
6177 // The size of an entry in the PLT.
6178 static const int plt_entry_size = 64;
6179
6180 // The first entry in the PLT.
6181 static const unsigned char first_plt_entry[plt_entry_size];
6182
6183 // Other entries in the PLT for an executable.
6184 static const unsigned char plt_entry[plt_entry_size];
6185
6186 // The reserved TLSDESC entry in the PLT for an executable.
6187 static const unsigned char tlsdesc_plt_entry[plt_entry_size];
6188
6189 // The .eh_frame unwind information for the PLT.
6190 static const int plt_eh_frame_fde_size = 32;
6191 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
6192 };
6193
6194 template<int size>
6195 class Target_x86_64_nacl : public Target_x86_64<size>
6196 {
6197 public:
6198 Target_x86_64_nacl()
6199 : Target_x86_64<size>(&x86_64_nacl_info)
6200 { }
6201
6202 virtual Output_data_plt_x86_64<size>*
6203 do_make_data_plt(Layout* layout,
6204 Output_data_got<64, false>* got,
6205 Output_data_got_plt_x86_64* got_plt,
6206 Output_data_space* got_irelative)
6207 {
6208 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
6209 got_irelative);
6210 }
6211
6212 virtual Output_data_plt_x86_64<size>*
6213 do_make_data_plt(Layout* layout,
6214 Output_data_got<64, false>* got,
6215 Output_data_got_plt_x86_64* got_plt,
6216 Output_data_space* got_irelative,
6217 unsigned int plt_count)
6218 {
6219 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
6220 got_irelative,
6221 plt_count);
6222 }
6223
6224 virtual std::string
6225 do_code_fill(section_size_type length) const;
6226
6227 private:
6228 static const Target::Target_info x86_64_nacl_info;
6229 };
6230
6231 template<>
6232 const Target::Target_info Target_x86_64_nacl<64>::x86_64_nacl_info =
6233 {
6234 64, // size
6235 false, // is_big_endian
6236 elfcpp::EM_X86_64, // machine_code
6237 false, // has_make_symbol
6238 false, // has_resolve
6239 true, // has_code_fill
6240 true, // is_default_stack_executable
6241 true, // can_icf_inline_merge_sections
6242 '\0', // wrap_char
6243 "/lib64/ld-nacl-x86-64.so.1", // dynamic_linker
6244 0x20000, // default_text_segment_address
6245 0x10000, // abi_pagesize (overridable by -z max-page-size)
6246 0x10000, // common_pagesize (overridable by -z common-page-size)
6247 true, // isolate_execinstr
6248 0x10000000, // rosegment_gap
6249 elfcpp::SHN_UNDEF, // small_common_shndx
6250 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
6251 0, // small_common_section_flags
6252 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
6253 NULL, // attributes_section
6254 NULL, // attributes_vendor
6255 "_start", // entry_symbol_name
6256 32, // hash_entry_size
6257 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type
6258 };
6259
6260 template<>
6261 const Target::Target_info Target_x86_64_nacl<32>::x86_64_nacl_info =
6262 {
6263 32, // size
6264 false, // is_big_endian
6265 elfcpp::EM_X86_64, // machine_code
6266 false, // has_make_symbol
6267 false, // has_resolve
6268 true, // has_code_fill
6269 true, // is_default_stack_executable
6270 true, // can_icf_inline_merge_sections
6271 '\0', // wrap_char
6272 "/lib/ld-nacl-x86-64.so.1", // dynamic_linker
6273 0x20000, // default_text_segment_address
6274 0x10000, // abi_pagesize (overridable by -z max-page-size)
6275 0x10000, // common_pagesize (overridable by -z common-page-size)
6276 true, // isolate_execinstr
6277 0x10000000, // rosegment_gap
6278 elfcpp::SHN_UNDEF, // small_common_shndx
6279 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
6280 0, // small_common_section_flags
6281 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
6282 NULL, // attributes_section
6283 NULL, // attributes_vendor
6284 "_start", // entry_symbol_name
6285 32, // hash_entry_size
6286 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type
6287 };
6288
6289 #define NACLMASK 0xe0 // 32-byte alignment mask.
6290
6291 // The first entry in the PLT.
6292
6293 template<int size>
6294 const unsigned char
6295 Output_data_plt_x86_64_nacl<size>::first_plt_entry[plt_entry_size] =
6296 {
6297 0xff, 0x35, // pushq contents of memory address
6298 0, 0, 0, 0, // replaced with address of .got + 8
6299 0x4c, 0x8b, 0x1d, // mov GOT+16(%rip), %r11
6300 0, 0, 0, 0, // replaced with address of .got + 16
6301 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
6302 0x4d, 0x01, 0xfb, // add %r15, %r11
6303 0x41, 0xff, 0xe3, // jmpq *%r11
6304
6305 // 9-byte nop sequence to pad out to the next 32-byte boundary.
6306 0x66, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw 0x0(%rax,%rax,1)
6307
6308 // 32 bytes of nop to pad out to the standard size
6309 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6310 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6311 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6312 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6313 0x66, // excess data32 prefix
6314 0x90 // nop
6315 };
6316
6317 template<int size>
6318 void
6319 Output_data_plt_x86_64_nacl<size>::do_fill_first_plt_entry(
6320 unsigned char* pov,
6321 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
6322 typename elfcpp::Elf_types<size>::Elf_Addr plt_address)
6323 {
6324 memcpy(pov, first_plt_entry, plt_entry_size);
6325 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
6326 (got_address + 8
6327 - (plt_address + 2 + 4)));
6328 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
6329 (got_address + 16
6330 - (plt_address + 9 + 4)));
6331 }
6332
6333 // Subsequent entries in the PLT.
6334
6335 template<int size>
6336 const unsigned char
6337 Output_data_plt_x86_64_nacl<size>::plt_entry[plt_entry_size] =
6338 {
6339 0x4c, 0x8b, 0x1d, // mov name@GOTPCREL(%rip),%r11
6340 0, 0, 0, 0, // replaced with address of symbol in .got
6341 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
6342 0x4d, 0x01, 0xfb, // add %r15, %r11
6343 0x41, 0xff, 0xe3, // jmpq *%r11
6344
6345 // 15-byte nop sequence to pad out to the next 32-byte boundary.
6346 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6347 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6348
6349 // Lazy GOT entries point here (32-byte aligned).
6350 0x68, // pushq immediate
6351 0, 0, 0, 0, // replaced with index into relocation table
6352 0xe9, // jmp relative
6353 0, 0, 0, 0, // replaced with offset to start of .plt0
6354
6355 // 22 bytes of nop to pad out to the standard size.
6356 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6357 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6358 0x0f, 0x1f, 0x80, 0, 0, 0, 0, // nopl 0x0(%rax)
6359 };
6360
6361 template<int size>
6362 unsigned int
6363 Output_data_plt_x86_64_nacl<size>::do_fill_plt_entry(
6364 unsigned char* pov,
6365 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
6366 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
6367 unsigned int got_offset,
6368 unsigned int plt_offset,
6369 unsigned int plt_index)
6370 {
6371 memcpy(pov, plt_entry, plt_entry_size);
6372 elfcpp::Swap_unaligned<32, false>::writeval(pov + 3,
6373 (got_address + got_offset
6374 - (plt_address + plt_offset
6375 + 3 + 4)));
6376
6377 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_index);
6378 elfcpp::Swap_unaligned<32, false>::writeval(pov + 38,
6379 - (plt_offset + 38 + 4));
6380
6381 return 32;
6382 }
6383
6384 // The reserved TLSDESC entry in the PLT.
6385
6386 template<int size>
6387 const unsigned char
6388 Output_data_plt_x86_64_nacl<size>::tlsdesc_plt_entry[plt_entry_size] =
6389 {
6390 0xff, 0x35, // pushq x(%rip)
6391 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
6392 0x4c, 0x8b, 0x1d, // mov y(%rip),%r11
6393 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
6394 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d
6395 0x4d, 0x01, 0xfb, // add %r15, %r11
6396 0x41, 0xff, 0xe3, // jmpq *%r11
6397
6398 // 41 bytes of nop to pad out to the standard size.
6399 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6400 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6401 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes
6402 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6403 0x66, 0x66, // excess data32 prefixes
6404 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1)
6405 };
6406
6407 template<int size>
6408 void
6409 Output_data_plt_x86_64_nacl<size>::do_fill_tlsdesc_entry(
6410 unsigned char* pov,
6411 typename elfcpp::Elf_types<size>::Elf_Addr got_address,
6412 typename elfcpp::Elf_types<size>::Elf_Addr plt_address,
6413 typename elfcpp::Elf_types<size>::Elf_Addr got_base,
6414 unsigned int tlsdesc_got_offset,
6415 unsigned int plt_offset)
6416 {
6417 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
6418 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
6419 (got_address + 8
6420 - (plt_address + plt_offset
6421 + 2 + 4)));
6422 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9,
6423 (got_base
6424 + tlsdesc_got_offset
6425 - (plt_address + plt_offset
6426 + 9 + 4)));
6427 }
6428
6429 // The .eh_frame unwind information for the PLT.
6430
6431 template<int size>
6432 const unsigned char
6433 Output_data_plt_x86_64_nacl<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
6434 {
6435 0, 0, 0, 0, // Replaced with offset to .plt.
6436 0, 0, 0, 0, // Replaced with size of .plt.
6437 0, // Augmentation size.
6438 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
6439 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
6440 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
6441 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
6442 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
6443 13, // Block length.
6444 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
6445 elfcpp::DW_OP_breg16, 0, // Push %rip.
6446 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
6447 elfcpp::DW_OP_and, // & (%rip & 0x3f).
6448 elfcpp::DW_OP_const1u, 37, // Push 0x25.
6449 elfcpp::DW_OP_ge, // >= ((%rip & 0x3f) >= 0x25)
6450 elfcpp::DW_OP_lit3, // Push 3.
6451 elfcpp::DW_OP_shl, // << (((%rip & 0x3f) >= 0x25) << 3)
6452 elfcpp::DW_OP_plus, // + ((((%rip&0x3f)>=0x25)<<3)+%rsp+8
6453 elfcpp::DW_CFA_nop, // Align to 32 bytes.
6454 elfcpp::DW_CFA_nop
6455 };
6456
6457 // Return a string used to fill a code section with nops.
6458 // For NaCl, long NOPs are only valid if they do not cross
6459 // bundle alignment boundaries, so keep it simple with one-byte NOPs.
6460 template<int size>
6461 std::string
6462 Target_x86_64_nacl<size>::do_code_fill(section_size_type length) const
6463 {
6464 return std::string(length, static_cast<char>(0x90));
6465 }
6466
6467 // The selector for x86_64-nacl object files.
6468
6469 template<int size>
6470 class Target_selector_x86_64_nacl
6471 : public Target_selector_nacl<Target_selector_x86_64<size>,
6472 Target_x86_64_nacl<size> >
6473 {
6474 public:
6475 Target_selector_x86_64_nacl()
6476 : Target_selector_nacl<Target_selector_x86_64<size>,
6477 Target_x86_64_nacl<size> >("x86-64",
6478 size == 64
6479 ? "elf64-x86-64-nacl"
6480 : "elf32-x86-64-nacl",
6481 size == 64
6482 ? "elf_x86_64_nacl"
6483 : "elf32_x86_64_nacl")
6484 { }
6485 };
6486
6487 Target_selector_x86_64_nacl<64> target_selector_x86_64;
6488 Target_selector_x86_64_nacl<32> target_selector_x32;
6489
6490 } // End anonymous namespace.
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