Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.24 / gold / i386.cc
CommitLineData
f40e693d
JM
1// i386.cc -- i386 target support for gold.
2
3// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
4// Free Software Foundation, Inc.
5// Written by Ian Lance Taylor <iant@google.com>.
6
7// This file is part of gold.
8
9// This program is free software; you can redistribute it and/or modify
10// it under the terms of the GNU General Public License as published by
11// the Free Software Foundation; either version 3 of the License, or
12// (at your option) any later version.
13
14// This program is distributed in the hope that it will be useful,
15// but WITHOUT ANY WARRANTY; without even the implied warranty of
16// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17// GNU General Public License for more details.
18
19// You should have received a copy of the GNU General Public License
20// along with this program; if not, write to the Free Software
21// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22// MA 02110-1301, USA.
23
24#include "gold.h"
25
26#include <cstring>
27
28#include "elfcpp.h"
29#include "dwarf.h"
30#include "parameters.h"
31#include "reloc.h"
32#include "i386.h"
33#include "object.h"
34#include "symtab.h"
35#include "layout.h"
36#include "output.h"
37#include "copy-relocs.h"
38#include "target.h"
39#include "target-reloc.h"
40#include "target-select.h"
41#include "tls.h"
42#include "freebsd.h"
43#include "nacl.h"
44#include "gc.h"
45
46namespace
47{
48
49using namespace gold;
50
51// A class to handle the PLT data.
52// This is an abstract base class that handles most of the linker details
53// but does not know the actual contents of PLT entries. The derived
54// classes below fill in those details.
55
56class Output_data_plt_i386 : public Output_section_data
57{
58 public:
59 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
60
61 Output_data_plt_i386(Layout*, uint64_t addralign,
62 Output_data_space*, Output_data_space*);
63
64 // Add an entry to the PLT.
65 void
66 add_entry(Symbol_table*, Layout*, Symbol* gsym);
67
68 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
69 unsigned int
70 add_local_ifunc_entry(Symbol_table*, Layout*,
71 Sized_relobj_file<32, false>* relobj,
72 unsigned int local_sym_index);
73
74 // Return the .rel.plt section data.
75 Reloc_section*
76 rel_plt() const
77 { return this->rel_; }
78
79 // Return where the TLS_DESC relocations should go.
80 Reloc_section*
81 rel_tls_desc(Layout*);
82
83 // Return where the IRELATIVE relocations should go.
84 Reloc_section*
85 rel_irelative(Symbol_table*, Layout*);
86
87 // Return whether we created a section for IRELATIVE relocations.
88 bool
89 has_irelative_section() const
90 { return this->irelative_rel_ != NULL; }
91
92 // Return the number of PLT entries.
93 unsigned int
94 entry_count() const
95 { return this->count_ + this->irelative_count_; }
96
97 // Return the offset of the first non-reserved PLT entry.
98 unsigned int
99 first_plt_entry_offset()
100 { return this->get_plt_entry_size(); }
101
102 // Return the size of a PLT entry.
103 unsigned int
104 get_plt_entry_size() const
105 { return this->do_get_plt_entry_size(); }
106
107 // Return the PLT address to use for a global symbol.
108 uint64_t
109 address_for_global(const Symbol*);
110
111 // Return the PLT address to use for a local symbol.
112 uint64_t
113 address_for_local(const Relobj*, unsigned int symndx);
114
115 // Add .eh_frame information for the PLT.
116 void
117 add_eh_frame(Layout* layout)
118 { this->do_add_eh_frame(layout); }
119
120 protected:
121 // Fill the first PLT entry, given the pointer to the PLT section data
122 // and the runtime address of the GOT.
123 void
124 fill_first_plt_entry(unsigned char* pov,
125 elfcpp::Elf_types<32>::Elf_Addr got_address)
126 { this->do_fill_first_plt_entry(pov, got_address); }
127
128 // Fill a normal PLT entry, given the pointer to the entry's data in the
129 // section, the runtime address of the GOT, the offset into the GOT of
130 // the corresponding slot, the offset into the relocation section of the
131 // corresponding reloc, and the offset of this entry within the whole
132 // PLT. Return the offset from this PLT entry's runtime address that
133 // should be used to compute the initial value of the GOT slot.
134 unsigned int
135 fill_plt_entry(unsigned char* pov,
136 elfcpp::Elf_types<32>::Elf_Addr got_address,
137 unsigned int got_offset,
138 unsigned int plt_offset,
139 unsigned int plt_rel_offset)
140 {
141 return this->do_fill_plt_entry(pov, got_address, got_offset,
142 plt_offset, plt_rel_offset);
143 }
144
145 virtual unsigned int
146 do_get_plt_entry_size() const = 0;
147
148 virtual void
149 do_fill_first_plt_entry(unsigned char* pov,
150 elfcpp::Elf_types<32>::Elf_Addr got_address) = 0;
151
152 virtual unsigned int
153 do_fill_plt_entry(unsigned char* pov,
154 elfcpp::Elf_types<32>::Elf_Addr got_address,
155 unsigned int got_offset,
156 unsigned int plt_offset,
157 unsigned int plt_rel_offset) = 0;
158
159 virtual void
160 do_add_eh_frame(Layout*) = 0;
161
162 void
163 do_adjust_output_section(Output_section* os);
164
165 // Write to a map file.
166 void
167 do_print_to_mapfile(Mapfile* mapfile) const
168 { mapfile->print_output_data(this, _("** PLT")); }
169
170 // The .eh_frame unwind information for the PLT.
171 // The CIE is common across variants of the PLT format.
172 static const int plt_eh_frame_cie_size = 16;
173 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
174
175 private:
176 // Set the final size.
177 void
178 set_final_data_size()
179 {
180 this->set_data_size((this->count_ + this->irelative_count_ + 1)
181 * this->get_plt_entry_size());
182 }
183
184 // Write out the PLT data.
185 void
186 do_write(Output_file*);
187
188 // We keep a list of global STT_GNU_IFUNC symbols, each with its
189 // offset in the GOT.
190 struct Global_ifunc
191 {
192 Symbol* sym;
193 unsigned int got_offset;
194 };
195
196 // We keep a list of local STT_GNU_IFUNC symbols, each with its
197 // offset in the GOT.
198 struct Local_ifunc
199 {
200 Sized_relobj_file<32, false>* object;
201 unsigned int local_sym_index;
202 unsigned int got_offset;
203 };
204
205 // A pointer to the Layout class, so that we can find the .dynamic
206 // section when we write out the GOT PLT section.
207 Layout* layout_;
208 // The reloc section.
209 Reloc_section* rel_;
210 // The TLS_DESC relocations, if necessary. These must follow the
211 // regular PLT relocs.
212 Reloc_section* tls_desc_rel_;
213 // The IRELATIVE relocations, if necessary. These must follow the
214 // regular relocatoins and the TLS_DESC relocations.
215 Reloc_section* irelative_rel_;
216 // The .got.plt section.
217 Output_data_space* got_plt_;
218 // The part of the .got.plt section used for IRELATIVE relocs.
219 Output_data_space* got_irelative_;
220 // The number of PLT entries.
221 unsigned int count_;
222 // Number of PLT entries with R_386_IRELATIVE relocs. These follow
223 // the regular PLT entries.
224 unsigned int irelative_count_;
225 // Global STT_GNU_IFUNC symbols.
226 std::vector<Global_ifunc> global_ifuncs_;
227 // Local STT_GNU_IFUNC symbols.
228 std::vector<Local_ifunc> local_ifuncs_;
229};
230
231// This is an abstract class for the standard PLT layout.
232// The derived classes below handle the actual PLT contents
233// for the executable (non-PIC) and shared-library (PIC) cases.
234// The unwind information is uniform across those two, so it's here.
235
236class Output_data_plt_i386_standard : public Output_data_plt_i386
237{
238 public:
239 Output_data_plt_i386_standard(Layout* layout,
240 Output_data_space* got_plt,
241 Output_data_space* got_irelative)
242 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
243 { }
244
245 protected:
246 virtual unsigned int
247 do_get_plt_entry_size() const
248 { return plt_entry_size; }
249
250 virtual void
251 do_add_eh_frame(Layout* layout)
252 {
253 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
254 plt_eh_frame_fde, plt_eh_frame_fde_size);
255 }
256
257 // The size of an entry in the PLT.
258 static const int plt_entry_size = 16;
259
260 // The .eh_frame unwind information for the PLT.
261 static const int plt_eh_frame_fde_size = 32;
262 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
263};
264
265// Actually fill the PLT contents for an executable (non-PIC).
266
267class Output_data_plt_i386_exec : public Output_data_plt_i386_standard
268{
269public:
270 Output_data_plt_i386_exec(Layout* layout,
271 Output_data_space* got_plt,
272 Output_data_space* got_irelative)
273 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
274 { }
275
276 protected:
277 virtual void
278 do_fill_first_plt_entry(unsigned char* pov,
279 elfcpp::Elf_types<32>::Elf_Addr got_address);
280
281 virtual unsigned int
282 do_fill_plt_entry(unsigned char* pov,
283 elfcpp::Elf_types<32>::Elf_Addr got_address,
284 unsigned int got_offset,
285 unsigned int plt_offset,
286 unsigned int plt_rel_offset);
287
288 private:
289 // The first entry in the PLT for an executable.
290 static const unsigned char first_plt_entry[plt_entry_size];
291
292 // Other entries in the PLT for an executable.
293 static const unsigned char plt_entry[plt_entry_size];
294};
295
296// Actually fill the PLT contents for a shared library (PIC).
297
298class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard
299{
300 public:
301 Output_data_plt_i386_dyn(Layout* layout,
302 Output_data_space* got_plt,
303 Output_data_space* got_irelative)
304 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
305 { }
306
307 protected:
308 virtual void
309 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
310
311 virtual unsigned int
312 do_fill_plt_entry(unsigned char* pov,
313 elfcpp::Elf_types<32>::Elf_Addr,
314 unsigned int got_offset,
315 unsigned int plt_offset,
316 unsigned int plt_rel_offset);
317
318 private:
319 // The first entry in the PLT for a shared object.
320 static const unsigned char first_plt_entry[plt_entry_size];
321
322 // Other entries in the PLT for a shared object.
323 static const unsigned char plt_entry[plt_entry_size];
324};
325
326// The i386 target class.
327// TLS info comes from
328// http://people.redhat.com/drepper/tls.pdf
329// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
330
331class Target_i386 : public Sized_target<32, false>
332{
333 public:
334 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
335
336 Target_i386(const Target::Target_info* info = &i386_info)
337 : Sized_target<32, false>(info),
338 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
339 got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL),
340 rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY),
341 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
342 { }
343
344 // Process the relocations to determine unreferenced sections for
345 // garbage collection.
346 void
347 gc_process_relocs(Symbol_table* symtab,
348 Layout* layout,
349 Sized_relobj_file<32, false>* object,
350 unsigned int data_shndx,
351 unsigned int sh_type,
352 const unsigned char* prelocs,
353 size_t reloc_count,
354 Output_section* output_section,
355 bool needs_special_offset_handling,
356 size_t local_symbol_count,
357 const unsigned char* plocal_symbols);
358
359 // Scan the relocations to look for symbol adjustments.
360 void
361 scan_relocs(Symbol_table* symtab,
362 Layout* layout,
363 Sized_relobj_file<32, false>* object,
364 unsigned int data_shndx,
365 unsigned int sh_type,
366 const unsigned char* prelocs,
367 size_t reloc_count,
368 Output_section* output_section,
369 bool needs_special_offset_handling,
370 size_t local_symbol_count,
371 const unsigned char* plocal_symbols);
372
373 // Finalize the sections.
374 void
375 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
376
377 // Return the value to use for a dynamic which requires special
378 // treatment.
379 uint64_t
380 do_dynsym_value(const Symbol*) const;
381
382 // Relocate a section.
383 void
384 relocate_section(const Relocate_info<32, false>*,
385 unsigned int sh_type,
386 const unsigned char* prelocs,
387 size_t reloc_count,
388 Output_section* output_section,
389 bool needs_special_offset_handling,
390 unsigned char* view,
391 elfcpp::Elf_types<32>::Elf_Addr view_address,
392 section_size_type view_size,
393 const Reloc_symbol_changes*);
394
395 // Scan the relocs during a relocatable link.
396 void
397 scan_relocatable_relocs(Symbol_table* symtab,
398 Layout* layout,
399 Sized_relobj_file<32, false>* object,
400 unsigned int data_shndx,
401 unsigned int sh_type,
402 const unsigned char* prelocs,
403 size_t reloc_count,
404 Output_section* output_section,
405 bool needs_special_offset_handling,
406 size_t local_symbol_count,
407 const unsigned char* plocal_symbols,
408 Relocatable_relocs*);
409
410 // Emit relocations for a section.
411 void
412 relocate_relocs(const Relocate_info<32, false>*,
413 unsigned int sh_type,
414 const unsigned char* prelocs,
415 size_t reloc_count,
416 Output_section* output_section,
417 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
418 const Relocatable_relocs*,
419 unsigned char* view,
420 elfcpp::Elf_types<32>::Elf_Addr view_address,
421 section_size_type view_size,
422 unsigned char* reloc_view,
423 section_size_type reloc_view_size);
424
425 // Return a string used to fill a code section with nops.
426 std::string
427 do_code_fill(section_size_type length) const;
428
429 // Return whether SYM is defined by the ABI.
430 bool
431 do_is_defined_by_abi(const Symbol* sym) const
432 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
433
434 // Return whether a symbol name implies a local label. The UnixWare
435 // 2.1 cc generates temporary symbols that start with .X, so we
436 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
437 // If so, we should move the .X recognition into
438 // Target::do_is_local_label_name.
439 bool
440 do_is_local_label_name(const char* name) const
441 {
442 if (name[0] == '.' && name[1] == 'X')
443 return true;
444 return Target::do_is_local_label_name(name);
445 }
446
447 // Return the PLT address to use for a global symbol.
448 uint64_t
449 do_plt_address_for_global(const Symbol* gsym) const
450 { return this->plt_section()->address_for_global(gsym); }
451
452 uint64_t
453 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
454 { return this->plt_section()->address_for_local(relobj, symndx); }
455
456 // We can tell whether we take the address of a function.
457 inline bool
458 do_can_check_for_function_pointers() const
459 { return true; }
460
461 // Return the base for a DW_EH_PE_datarel encoding.
462 uint64_t
463 do_ehframe_datarel_base() const;
464
465 // Return whether SYM is call to a non-split function.
466 bool
467 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
468
469 // Adjust -fsplit-stack code which calls non-split-stack code.
470 void
471 do_calls_non_split(Relobj* object, unsigned int shndx,
472 section_offset_type fnoffset, section_size_type fnsize,
473 unsigned char* view, section_size_type view_size,
474 std::string* from, std::string* to) const;
475
476 // Return the size of the GOT section.
477 section_size_type
478 got_size() const
479 {
480 gold_assert(this->got_ != NULL);
481 return this->got_->data_size();
482 }
483
484 // Return the number of entries in the GOT.
485 unsigned int
486 got_entry_count() const
487 {
488 if (this->got_ == NULL)
489 return 0;
490 return this->got_size() / 4;
491 }
492
493 // Return the number of entries in the PLT.
494 unsigned int
495 plt_entry_count() const;
496
497 // Return the offset of the first non-reserved PLT entry.
498 unsigned int
499 first_plt_entry_offset() const;
500
501 // Return the size of each PLT entry.
502 unsigned int
503 plt_entry_size() const;
504
505 protected:
506 // Instantiate the plt_ member.
507 // This chooses the right PLT flavor for an executable or a shared object.
508 Output_data_plt_i386*
509 make_data_plt(Layout* layout,
510 Output_data_space* got_plt,
511 Output_data_space* got_irelative,
512 bool dyn)
513 { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); }
514
515 virtual Output_data_plt_i386*
516 do_make_data_plt(Layout* layout,
517 Output_data_space* got_plt,
518 Output_data_space* got_irelative,
519 bool dyn)
520 {
521 if (dyn)
522 return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative);
523 else
524 return new Output_data_plt_i386_exec(layout, got_plt, got_irelative);
525 }
526
527 private:
528 // The class which scans relocations.
529 struct Scan
530 {
531 static inline int
532
533 get_reference_flags(unsigned int r_type);
534
535 inline void
536 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
537 Sized_relobj_file<32, false>* object,
538 unsigned int data_shndx,
539 Output_section* output_section,
540 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
541 const elfcpp::Sym<32, false>& lsym,
542 bool is_discarded);
543
544 inline void
545 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
546 Sized_relobj_file<32, false>* object,
547 unsigned int data_shndx,
548 Output_section* output_section,
549 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
550 Symbol* gsym);
551
552 inline bool
553 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
554 Target_i386* target,
555 Sized_relobj_file<32, false>* object,
556 unsigned int data_shndx,
557 Output_section* output_section,
558 const elfcpp::Rel<32, false>& reloc,
559 unsigned int r_type,
560 const elfcpp::Sym<32, false>& lsym);
561
562 inline bool
563 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
564 Target_i386* target,
565 Sized_relobj_file<32, false>* object,
566 unsigned int data_shndx,
567 Output_section* output_section,
568 const elfcpp::Rel<32, false>& reloc,
569 unsigned int r_type,
570 Symbol* gsym);
571
572 inline bool
573 possible_function_pointer_reloc(unsigned int r_type);
574
575 bool
576 reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*,
577 unsigned int r_type);
578
579 static void
580 unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type);
581
582 static void
583 unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type,
584 Symbol*);
585 };
586
587 // The class which implements relocation.
588 class Relocate
589 {
590 public:
591 Relocate()
592 : skip_call_tls_get_addr_(false),
593 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
594 { }
595
596 ~Relocate()
597 {
598 if (this->skip_call_tls_get_addr_)
599 {
600 // FIXME: This needs to specify the location somehow.
601 gold_error(_("missing expected TLS relocation"));
602 }
603 }
604
605 // Return whether the static relocation needs to be applied.
606 inline bool
607 should_apply_static_reloc(const Sized_symbol<32>* gsym,
608 unsigned int r_type,
609 bool is_32bit,
610 Output_section* output_section);
611
612 // Do a relocation. Return false if the caller should not issue
613 // any warnings about this relocation.
614 inline bool
615 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
616 size_t relnum, const elfcpp::Rel<32, false>&,
617 unsigned int r_type, const Sized_symbol<32>*,
618 const Symbol_value<32>*,
619 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
620 section_size_type);
621
622 private:
623 // Do a TLS relocation.
624 inline void
625 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
626 size_t relnum, const elfcpp::Rel<32, false>&,
627 unsigned int r_type, const Sized_symbol<32>*,
628 const Symbol_value<32>*,
629 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
630 section_size_type);
631
632 // Do a TLS General-Dynamic to Initial-Exec transition.
633 inline void
634 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
635 Output_segment* tls_segment,
636 const elfcpp::Rel<32, false>&, unsigned int r_type,
637 elfcpp::Elf_types<32>::Elf_Addr value,
638 unsigned char* view,
639 section_size_type view_size);
640
641 // Do a TLS General-Dynamic to Local-Exec transition.
642 inline void
643 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
644 Output_segment* tls_segment,
645 const elfcpp::Rel<32, false>&, unsigned int r_type,
646 elfcpp::Elf_types<32>::Elf_Addr value,
647 unsigned char* view,
648 section_size_type view_size);
649
650 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
651 // transition.
652 inline void
653 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
654 Output_segment* tls_segment,
655 const elfcpp::Rel<32, false>&, unsigned int r_type,
656 elfcpp::Elf_types<32>::Elf_Addr value,
657 unsigned char* view,
658 section_size_type view_size);
659
660 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
661 // transition.
662 inline void
663 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
664 Output_segment* tls_segment,
665 const elfcpp::Rel<32, false>&, unsigned int r_type,
666 elfcpp::Elf_types<32>::Elf_Addr value,
667 unsigned char* view,
668 section_size_type view_size);
669
670 // Do a TLS Local-Dynamic to Local-Exec transition.
671 inline void
672 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
673 Output_segment* tls_segment,
674 const elfcpp::Rel<32, false>&, unsigned int r_type,
675 elfcpp::Elf_types<32>::Elf_Addr value,
676 unsigned char* view,
677 section_size_type view_size);
678
679 // Do a TLS Initial-Exec to Local-Exec transition.
680 static inline void
681 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
682 Output_segment* tls_segment,
683 const elfcpp::Rel<32, false>&, unsigned int r_type,
684 elfcpp::Elf_types<32>::Elf_Addr value,
685 unsigned char* view,
686 section_size_type view_size);
687
688 // We need to keep track of which type of local dynamic relocation
689 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
690 enum Local_dynamic_type
691 {
692 LOCAL_DYNAMIC_NONE,
693 LOCAL_DYNAMIC_SUN,
694 LOCAL_DYNAMIC_GNU
695 };
696
697 // This is set if we should skip the next reloc, which should be a
698 // PLT32 reloc against ___tls_get_addr.
699 bool skip_call_tls_get_addr_;
700 // The type of local dynamic relocation we have seen in the section
701 // being relocated, if any.
702 Local_dynamic_type local_dynamic_type_;
703 };
704
705 // A class which returns the size required for a relocation type,
706 // used while scanning relocs during a relocatable link.
707 class Relocatable_size_for_reloc
708 {
709 public:
710 unsigned int
711 get_size_for_reloc(unsigned int, Relobj*);
712 };
713
714 // Adjust TLS relocation type based on the options and whether this
715 // is a local symbol.
716 static tls::Tls_optimization
717 optimize_tls_reloc(bool is_final, int r_type);
718
719 // Get the GOT section, creating it if necessary.
720 Output_data_got<32, false>*
721 got_section(Symbol_table*, Layout*);
722
723 // Get the GOT PLT section.
724 Output_data_space*
725 got_plt_section() const
726 {
727 gold_assert(this->got_plt_ != NULL);
728 return this->got_plt_;
729 }
730
731 // Get the GOT section for TLSDESC entries.
732 Output_data_got<32, false>*
733 got_tlsdesc_section() const
734 {
735 gold_assert(this->got_tlsdesc_ != NULL);
736 return this->got_tlsdesc_;
737 }
738
739 // Create the PLT section.
740 void
741 make_plt_section(Symbol_table* symtab, Layout* layout);
742
743 // Create a PLT entry for a global symbol.
744 void
745 make_plt_entry(Symbol_table*, Layout*, Symbol*);
746
747 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
748 void
749 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
750 Sized_relobj_file<32, false>* relobj,
751 unsigned int local_sym_index);
752
753 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
754 void
755 define_tls_base_symbol(Symbol_table*, Layout*);
756
757 // Create a GOT entry for the TLS module index.
758 unsigned int
759 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
760 Sized_relobj_file<32, false>* object);
761
762 // Get the PLT section.
763 Output_data_plt_i386*
764 plt_section() const
765 {
766 gold_assert(this->plt_ != NULL);
767 return this->plt_;
768 }
769
770 // Get the dynamic reloc section, creating it if necessary.
771 Reloc_section*
772 rel_dyn_section(Layout*);
773
774 // Get the section to use for TLS_DESC relocations.
775 Reloc_section*
776 rel_tls_desc_section(Layout*) const;
777
778 // Get the section to use for IRELATIVE relocations.
779 Reloc_section*
780 rel_irelative_section(Layout*);
781
782 // Add a potential copy relocation.
783 void
784 copy_reloc(Symbol_table* symtab, Layout* layout,
785 Sized_relobj_file<32, false>* object,
786 unsigned int shndx, Output_section* output_section,
787 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
788 {
789 this->copy_relocs_.copy_reloc(symtab, layout,
790 symtab->get_sized_symbol<32>(sym),
791 object, shndx, output_section, reloc,
792 this->rel_dyn_section(layout));
793 }
794
795 // Information about this specific target which we pass to the
796 // general Target structure.
797 static const Target::Target_info i386_info;
798
799 // The types of GOT entries needed for this platform.
800 // These values are exposed to the ABI in an incremental link.
801 // Do not renumber existing values without changing the version
802 // number of the .gnu_incremental_inputs section.
803 enum Got_type
804 {
805 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
806 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
807 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
808 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
809 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
810 };
811
812 // The GOT section.
813 Output_data_got<32, false>* got_;
814 // The PLT section.
815 Output_data_plt_i386* plt_;
816 // The GOT PLT section.
817 Output_data_space* got_plt_;
818 // The GOT section for IRELATIVE relocations.
819 Output_data_space* got_irelative_;
820 // The GOT section for TLSDESC relocations.
821 Output_data_got<32, false>* got_tlsdesc_;
822 // The _GLOBAL_OFFSET_TABLE_ symbol.
823 Symbol* global_offset_table_;
824 // The dynamic reloc section.
825 Reloc_section* rel_dyn_;
826 // The section to use for IRELATIVE relocs.
827 Reloc_section* rel_irelative_;
828 // Relocs saved to avoid a COPY reloc.
829 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
830 // Offset of the GOT entry for the TLS module index.
831 unsigned int got_mod_index_offset_;
832 // True if the _TLS_MODULE_BASE_ symbol has been defined.
833 bool tls_base_symbol_defined_;
834};
835
836const Target::Target_info Target_i386::i386_info =
837{
838 32, // size
839 false, // is_big_endian
840 elfcpp::EM_386, // machine_code
841 false, // has_make_symbol
842 false, // has_resolve
843 true, // has_code_fill
844 true, // is_default_stack_executable
845 true, // can_icf_inline_merge_sections
846 '\0', // wrap_char
847 "/usr/lib/libc.so.1", // dynamic_linker
848 0x08048000, // default_text_segment_address
849 0x1000, // abi_pagesize (overridable by -z max-page-size)
850 0x1000, // common_pagesize (overridable by -z common-page-size)
851 false, // isolate_execinstr
852 0, // rosegment_gap
853 elfcpp::SHN_UNDEF, // small_common_shndx
854 elfcpp::SHN_UNDEF, // large_common_shndx
855 0, // small_common_section_flags
856 0, // large_common_section_flags
857 NULL, // attributes_section
858 NULL, // attributes_vendor
859 "_start" // entry_symbol_name
860};
861
862// Get the GOT section, creating it if necessary.
863
864Output_data_got<32, false>*
865Target_i386::got_section(Symbol_table* symtab, Layout* layout)
866{
867 if (this->got_ == NULL)
868 {
869 gold_assert(symtab != NULL && layout != NULL);
870
871 this->got_ = new Output_data_got<32, false>();
872
873 // When using -z now, we can treat .got.plt as a relro section.
874 // Without -z now, it is modified after program startup by lazy
875 // PLT relocations.
876 bool is_got_plt_relro = parameters->options().now();
877 Output_section_order got_order = (is_got_plt_relro
878 ? ORDER_RELRO
879 : ORDER_RELRO_LAST);
880 Output_section_order got_plt_order = (is_got_plt_relro
881 ? ORDER_RELRO
882 : ORDER_NON_RELRO_FIRST);
883
884 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
885 (elfcpp::SHF_ALLOC
886 | elfcpp::SHF_WRITE),
887 this->got_, got_order, true);
888
889 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
890 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
891 (elfcpp::SHF_ALLOC
892 | elfcpp::SHF_WRITE),
893 this->got_plt_, got_plt_order,
894 is_got_plt_relro);
895
896 // The first three entries are reserved.
897 this->got_plt_->set_current_data_size(3 * 4);
898
899 if (!is_got_plt_relro)
900 {
901 // Those bytes can go into the relro segment.
902 layout->increase_relro(3 * 4);
903 }
904
905 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
906 this->global_offset_table_ =
907 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
908 Symbol_table::PREDEFINED,
909 this->got_plt_,
910 0, 0, elfcpp::STT_OBJECT,
911 elfcpp::STB_LOCAL,
912 elfcpp::STV_HIDDEN, 0,
913 false, false);
914
915 // If there are any IRELATIVE relocations, they get GOT entries
916 // in .got.plt after the jump slot relocations.
917 this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT");
918 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
919 (elfcpp::SHF_ALLOC
920 | elfcpp::SHF_WRITE),
921 this->got_irelative_,
922 got_plt_order, is_got_plt_relro);
923
924 // If there are any TLSDESC relocations, they get GOT entries in
925 // .got.plt after the jump slot entries.
926 this->got_tlsdesc_ = new Output_data_got<32, false>();
927 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
928 (elfcpp::SHF_ALLOC
929 | elfcpp::SHF_WRITE),
930 this->got_tlsdesc_,
931 got_plt_order, is_got_plt_relro);
932 }
933
934 return this->got_;
935}
936
937// Get the dynamic reloc section, creating it if necessary.
938
939Target_i386::Reloc_section*
940Target_i386::rel_dyn_section(Layout* layout)
941{
942 if (this->rel_dyn_ == NULL)
943 {
944 gold_assert(layout != NULL);
945 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
946 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
947 elfcpp::SHF_ALLOC, this->rel_dyn_,
948 ORDER_DYNAMIC_RELOCS, false);
949 }
950 return this->rel_dyn_;
951}
952
953// Get the section to use for IRELATIVE relocs, creating it if
954// necessary. These go in .rel.dyn, but only after all other dynamic
955// relocations. They need to follow the other dynamic relocations so
956// that they can refer to global variables initialized by those
957// relocs.
958
959Target_i386::Reloc_section*
960Target_i386::rel_irelative_section(Layout* layout)
961{
962 if (this->rel_irelative_ == NULL)
963 {
964 // Make sure we have already create the dynamic reloc section.
965 this->rel_dyn_section(layout);
966 this->rel_irelative_ = new Reloc_section(false);
967 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
968 elfcpp::SHF_ALLOC, this->rel_irelative_,
969 ORDER_DYNAMIC_RELOCS, false);
970 gold_assert(this->rel_dyn_->output_section()
971 == this->rel_irelative_->output_section());
972 }
973 return this->rel_irelative_;
974}
975
976// Create the PLT section. The ordinary .got section is an argument,
977// since we need to refer to the start. We also create our own .got
978// section just for PLT entries.
979
980Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
981 uint64_t addralign,
982 Output_data_space* got_plt,
983 Output_data_space* got_irelative)
984 : Output_section_data(addralign),
985 layout_(layout), tls_desc_rel_(NULL),
986 irelative_rel_(NULL), got_plt_(got_plt), got_irelative_(got_irelative),
987 count_(0), irelative_count_(0), global_ifuncs_(), local_ifuncs_()
988{
989 this->rel_ = new Reloc_section(false);
990 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
991 elfcpp::SHF_ALLOC, this->rel_,
992 ORDER_DYNAMIC_PLT_RELOCS, false);
993}
994
995void
996Output_data_plt_i386::do_adjust_output_section(Output_section* os)
997{
998 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
999 // linker, and so do we.
1000 os->set_entsize(4);
1001}
1002
1003// Add an entry to the PLT.
1004
1005void
1006Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
1007 Symbol* gsym)
1008{
1009 gold_assert(!gsym->has_plt_offset());
1010
1011 // Every PLT entry needs a reloc.
1012 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1013 && gsym->can_use_relative_reloc(false))
1014 {
1015 gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size());
1016 ++this->irelative_count_;
1017 section_offset_type got_offset =
1018 this->got_irelative_->current_data_size();
1019 this->got_irelative_->set_current_data_size(got_offset + 4);
1020 Reloc_section* rel = this->rel_irelative(symtab, layout);
1021 rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
1022 this->got_irelative_, got_offset);
1023 struct Global_ifunc gi;
1024 gi.sym = gsym;
1025 gi.got_offset = got_offset;
1026 this->global_ifuncs_.push_back(gi);
1027 }
1028 else
1029 {
1030 // When setting the PLT offset we skip the initial reserved PLT
1031 // entry.
1032 gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size());
1033
1034 ++this->count_;
1035
1036 section_offset_type got_offset = this->got_plt_->current_data_size();
1037
1038 // Every PLT entry needs a GOT entry which points back to the
1039 // PLT entry (this will be changed by the dynamic linker,
1040 // normally lazily when the function is called).
1041 this->got_plt_->set_current_data_size(got_offset + 4);
1042
1043 gsym->set_needs_dynsym_entry();
1044 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
1045 got_offset);
1046 }
1047
1048 // Note that we don't need to save the symbol. The contents of the
1049 // PLT are independent of which symbols are used. The symbols only
1050 // appear in the relocations.
1051}
1052
1053// Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1054// the PLT offset.
1055
1056unsigned int
1057Output_data_plt_i386::add_local_ifunc_entry(
1058 Symbol_table* symtab,
1059 Layout* layout,
1060 Sized_relobj_file<32, false>* relobj,
1061 unsigned int local_sym_index)
1062{
1063 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1064 ++this->irelative_count_;
1065
1066 section_offset_type got_offset = this->got_irelative_->current_data_size();
1067
1068 // Every PLT entry needs a GOT entry which points back to the PLT
1069 // entry.
1070 this->got_irelative_->set_current_data_size(got_offset + 4);
1071
1072 // Every PLT entry needs a reloc.
1073 Reloc_section* rel = this->rel_irelative(symtab, layout);
1074 rel->add_symbolless_local_addend(relobj, local_sym_index,
1075 elfcpp::R_386_IRELATIVE,
1076 this->got_irelative_, got_offset);
1077
1078 struct Local_ifunc li;
1079 li.object = relobj;
1080 li.local_sym_index = local_sym_index;
1081 li.got_offset = got_offset;
1082 this->local_ifuncs_.push_back(li);
1083
1084 return plt_offset;
1085}
1086
1087// Return where the TLS_DESC relocations should go, creating it if
1088// necessary. These follow the JUMP_SLOT relocations.
1089
1090Output_data_plt_i386::Reloc_section*
1091Output_data_plt_i386::rel_tls_desc(Layout* layout)
1092{
1093 if (this->tls_desc_rel_ == NULL)
1094 {
1095 this->tls_desc_rel_ = new Reloc_section(false);
1096 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1097 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
1098 ORDER_DYNAMIC_PLT_RELOCS, false);
1099 gold_assert(this->tls_desc_rel_->output_section()
1100 == this->rel_->output_section());
1101 }
1102 return this->tls_desc_rel_;
1103}
1104
1105// Return where the IRELATIVE relocations should go in the PLT. These
1106// follow the JUMP_SLOT and TLS_DESC relocations.
1107
1108Output_data_plt_i386::Reloc_section*
1109Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
1110{
1111 if (this->irelative_rel_ == NULL)
1112 {
1113 // Make sure we have a place for the TLS_DESC relocations, in
1114 // case we see any later on.
1115 this->rel_tls_desc(layout);
1116 this->irelative_rel_ = new Reloc_section(false);
1117 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1118 elfcpp::SHF_ALLOC, this->irelative_rel_,
1119 ORDER_DYNAMIC_PLT_RELOCS, false);
1120 gold_assert(this->irelative_rel_->output_section()
1121 == this->rel_->output_section());
1122
1123 if (parameters->doing_static_link())
1124 {
1125 // A statically linked executable will only have a .rel.plt
1126 // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
1127 // symbols. The library will use these symbols to locate
1128 // the IRELATIVE relocs at program startup time.
1129 symtab->define_in_output_data("__rel_iplt_start", NULL,
1130 Symbol_table::PREDEFINED,
1131 this->irelative_rel_, 0, 0,
1132 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1133 elfcpp::STV_HIDDEN, 0, false, true);
1134 symtab->define_in_output_data("__rel_iplt_end", NULL,
1135 Symbol_table::PREDEFINED,
1136 this->irelative_rel_, 0, 0,
1137 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1138 elfcpp::STV_HIDDEN, 0, true, true);
1139 }
1140 }
1141 return this->irelative_rel_;
1142}
1143
1144// Return the PLT address to use for a global symbol.
1145
1146uint64_t
1147Output_data_plt_i386::address_for_global(const Symbol* gsym)
1148{
1149 uint64_t offset = 0;
1150 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1151 && gsym->can_use_relative_reloc(false))
1152 offset = (this->count_ + 1) * this->get_plt_entry_size();
1153 return this->address() + offset + gsym->plt_offset();
1154}
1155
1156// Return the PLT address to use for a local symbol. These are always
1157// IRELATIVE relocs.
1158
1159uint64_t
1160Output_data_plt_i386::address_for_local(const Relobj* object,
1161 unsigned int r_sym)
1162{
1163 return (this->address()
1164 + (this->count_ + 1) * this->get_plt_entry_size()
1165 + object->local_plt_offset(r_sym));
1166}
1167
1168// The first entry in the PLT for an executable.
1169
1170const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] =
1171{
1172 0xff, 0x35, // pushl contents of memory address
1173 0, 0, 0, 0, // replaced with address of .got + 4
1174 0xff, 0x25, // jmp indirect
1175 0, 0, 0, 0, // replaced with address of .got + 8
1176 0, 0, 0, 0 // unused
1177};
1178
1179void
1180Output_data_plt_i386_exec::do_fill_first_plt_entry(
1181 unsigned char* pov,
1182 elfcpp::Elf_types<32>::Elf_Addr got_address)
1183{
1184 memcpy(pov, first_plt_entry, plt_entry_size);
1185 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
1186 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
1187}
1188
1189// The first entry in the PLT for a shared object.
1190
1191const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] =
1192{
1193 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
1194 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
1195 0, 0, 0, 0 // unused
1196};
1197
1198void
1199Output_data_plt_i386_dyn::do_fill_first_plt_entry(
1200 unsigned char* pov,
1201 elfcpp::Elf_types<32>::Elf_Addr)
1202{
1203 memcpy(pov, first_plt_entry, plt_entry_size);
1204}
1205
1206// Subsequent entries in the PLT for an executable.
1207
1208const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] =
1209{
1210 0xff, 0x25, // jmp indirect
1211 0, 0, 0, 0, // replaced with address of symbol in .got
1212 0x68, // pushl immediate
1213 0, 0, 0, 0, // replaced with offset into relocation table
1214 0xe9, // jmp relative
1215 0, 0, 0, 0 // replaced with offset to start of .plt
1216};
1217
1218unsigned int
1219Output_data_plt_i386_exec::do_fill_plt_entry(
1220 unsigned char* pov,
1221 elfcpp::Elf_types<32>::Elf_Addr got_address,
1222 unsigned int got_offset,
1223 unsigned int plt_offset,
1224 unsigned int plt_rel_offset)
1225{
1226 memcpy(pov, plt_entry, plt_entry_size);
1227 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1228 got_address + got_offset);
1229 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1230 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1231 return 6;
1232}
1233
1234// Subsequent entries in the PLT for a shared object.
1235
1236const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] =
1237{
1238 0xff, 0xa3, // jmp *offset(%ebx)
1239 0, 0, 0, 0, // replaced with offset of symbol in .got
1240 0x68, // pushl immediate
1241 0, 0, 0, 0, // replaced with offset into relocation table
1242 0xe9, // jmp relative
1243 0, 0, 0, 0 // replaced with offset to start of .plt
1244};
1245
1246unsigned int
1247Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov,
1248 elfcpp::Elf_types<32>::Elf_Addr,
1249 unsigned int got_offset,
1250 unsigned int plt_offset,
1251 unsigned int plt_rel_offset)
1252{
1253 memcpy(pov, plt_entry, plt_entry_size);
1254 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
1255 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1256 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1257 return 6;
1258}
1259
1260// The .eh_frame unwind information for the PLT.
1261
1262const unsigned char
1263Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1264{
1265 1, // CIE version.
1266 'z', // Augmentation: augmentation size included.
1267 'R', // Augmentation: FDE encoding included.
1268 '\0', // End of augmentation string.
1269 1, // Code alignment factor.
1270 0x7c, // Data alignment factor.
1271 8, // Return address column.
1272 1, // Augmentation size.
1273 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1274 | elfcpp::DW_EH_PE_sdata4),
1275 elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
1276 elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
1277 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1278 elfcpp::DW_CFA_nop
1279};
1280
1281const unsigned char
1282Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1283{
1284 0, 0, 0, 0, // Replaced with offset to .plt.
1285 0, 0, 0, 0, // Replaced with size of .plt.
1286 0, // Augmentation size.
1287 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
1288 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1289 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
1290 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1291 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1292 11, // Block length.
1293 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
1294 elfcpp::DW_OP_breg8, 0, // Push %eip.
1295 elfcpp::DW_OP_lit15, // Push 0xf.
1296 elfcpp::DW_OP_and, // & (%eip & 0xf).
1297 elfcpp::DW_OP_lit11, // Push 0xb.
1298 elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
1299 elfcpp::DW_OP_lit2, // Push 2.
1300 elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
1301 elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4
1302 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1303 elfcpp::DW_CFA_nop,
1304 elfcpp::DW_CFA_nop,
1305 elfcpp::DW_CFA_nop
1306};
1307
1308// Write out the PLT. This uses the hand-coded instructions above,
1309// and adjusts them as needed. This is all specified by the i386 ELF
1310// Processor Supplement.
1311
1312void
1313Output_data_plt_i386::do_write(Output_file* of)
1314{
1315 const off_t offset = this->offset();
1316 const section_size_type oview_size =
1317 convert_to_section_size_type(this->data_size());
1318 unsigned char* const oview = of->get_output_view(offset, oview_size);
1319
1320 const off_t got_file_offset = this->got_plt_->offset();
1321 gold_assert(parameters->incremental_update()
1322 || (got_file_offset + this->got_plt_->data_size()
1323 == this->got_irelative_->offset()));
1324 const section_size_type got_size =
1325 convert_to_section_size_type(this->got_plt_->data_size()
1326 + this->got_irelative_->data_size());
1327 unsigned char* const got_view = of->get_output_view(got_file_offset,
1328 got_size);
1329
1330 unsigned char* pov = oview;
1331
1332 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
1333 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
1334
1335 this->fill_first_plt_entry(pov, got_address);
1336 pov += this->get_plt_entry_size();
1337
1338 unsigned char* got_pov = got_view;
1339
1340 // The first entry in the GOT is the address of the .dynamic section
1341 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1342 // We saved space for them when we created the section in
1343 // Target_i386::got_section.
1344 Output_section* dynamic = this->layout_->dynamic_section();
1345 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1346 elfcpp::Swap<32, false>::writeval(got_pov, dynamic_addr);
1347 got_pov += 4;
1348 memset(got_pov, 0, 8);
1349 got_pov += 8;
1350
1351 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
1352
1353 unsigned int plt_offset = this->get_plt_entry_size();
1354 unsigned int plt_rel_offset = 0;
1355 unsigned int got_offset = 12;
1356 const unsigned int count = this->count_ + this->irelative_count_;
1357 for (unsigned int i = 0;
1358 i < count;
1359 ++i,
1360 pov += this->get_plt_entry_size(),
1361 got_pov += 4,
1362 plt_offset += this->get_plt_entry_size(),
1363 plt_rel_offset += rel_size,
1364 got_offset += 4)
1365 {
1366 // Set and adjust the PLT entry itself.
1367 unsigned int lazy_offset = this->fill_plt_entry(pov,
1368 got_address,
1369 got_offset,
1370 plt_offset,
1371 plt_rel_offset);
1372
1373 // Set the entry in the GOT.
1374 elfcpp::Swap<32, false>::writeval(got_pov,
1375 plt_address + plt_offset + lazy_offset);
1376 }
1377
1378 // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
1379 // the GOT to point to the actual symbol value, rather than point to
1380 // the PLT entry. That will let the dynamic linker call the right
1381 // function when resolving IRELATIVE relocations.
1382 unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
1383 for (std::vector<Global_ifunc>::const_iterator p =
1384 this->global_ifuncs_.begin();
1385 p != this->global_ifuncs_.end();
1386 ++p)
1387 {
1388 const Sized_symbol<32>* ssym =
1389 static_cast<const Sized_symbol<32>*>(p->sym);
1390 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1391 ssym->value());
1392 }
1393
1394 for (std::vector<Local_ifunc>::const_iterator p =
1395 this->local_ifuncs_.begin();
1396 p != this->local_ifuncs_.end();
1397 ++p)
1398 {
1399 const Symbol_value<32>* psymval =
1400 p->object->local_symbol(p->local_sym_index);
1401 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1402 psymval->value(p->object, 0));
1403 }
1404
1405 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1406 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1407
1408 of->write_output_view(offset, oview_size, oview);
1409 of->write_output_view(got_file_offset, got_size, got_view);
1410}
1411
1412// Create the PLT section.
1413
1414void
1415Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
1416{
1417 if (this->plt_ == NULL)
1418 {
1419 // Create the GOT sections first.
1420 this->got_section(symtab, layout);
1421
1422 const bool dyn = parameters->options().output_is_position_independent();
1423 this->plt_ = this->make_data_plt(layout,
1424 this->got_plt_,
1425 this->got_irelative_,
1426 dyn);
1427
1428 // Add unwind information if requested.
1429 if (parameters->options().ld_generated_unwind_info())
1430 this->plt_->add_eh_frame(layout);
1431
1432 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1433 (elfcpp::SHF_ALLOC
1434 | elfcpp::SHF_EXECINSTR),
1435 this->plt_, ORDER_PLT, false);
1436
1437 // Make the sh_info field of .rel.plt point to .plt.
1438 Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
1439 rel_plt_os->set_info_section(this->plt_->output_section());
1440 }
1441}
1442
1443// Create a PLT entry for a global symbol.
1444
1445void
1446Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
1447{
1448 if (gsym->has_plt_offset())
1449 return;
1450 if (this->plt_ == NULL)
1451 this->make_plt_section(symtab, layout);
1452 this->plt_->add_entry(symtab, layout, gsym);
1453}
1454
1455// Make a PLT entry for a local STT_GNU_IFUNC symbol.
1456
1457void
1458Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1459 Sized_relobj_file<32, false>* relobj,
1460 unsigned int local_sym_index)
1461{
1462 if (relobj->local_has_plt_offset(local_sym_index))
1463 return;
1464 if (this->plt_ == NULL)
1465 this->make_plt_section(symtab, layout);
1466 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1467 relobj,
1468 local_sym_index);
1469 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1470}
1471
1472// Return the number of entries in the PLT.
1473
1474unsigned int
1475Target_i386::plt_entry_count() const
1476{
1477 if (this->plt_ == NULL)
1478 return 0;
1479 return this->plt_->entry_count();
1480}
1481
1482// Return the offset of the first non-reserved PLT entry.
1483
1484unsigned int
1485Target_i386::first_plt_entry_offset() const
1486{
1487 return this->plt_->first_plt_entry_offset();
1488}
1489
1490// Return the size of each PLT entry.
1491
1492unsigned int
1493Target_i386::plt_entry_size() const
1494{
1495 return this->plt_->get_plt_entry_size();
1496}
1497
1498// Get the section to use for TLS_DESC relocations.
1499
1500Target_i386::Reloc_section*
1501Target_i386::rel_tls_desc_section(Layout* layout) const
1502{
1503 return this->plt_section()->rel_tls_desc(layout);
1504}
1505
1506// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1507
1508void
1509Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1510{
1511 if (this->tls_base_symbol_defined_)
1512 return;
1513
1514 Output_segment* tls_segment = layout->tls_segment();
1515 if (tls_segment != NULL)
1516 {
1517 bool is_exec = parameters->options().output_is_executable();
1518 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1519 Symbol_table::PREDEFINED,
1520 tls_segment, 0, 0,
1521 elfcpp::STT_TLS,
1522 elfcpp::STB_LOCAL,
1523 elfcpp::STV_HIDDEN, 0,
1524 (is_exec
1525 ? Symbol::SEGMENT_END
1526 : Symbol::SEGMENT_START),
1527 true);
1528 }
1529 this->tls_base_symbol_defined_ = true;
1530}
1531
1532// Create a GOT entry for the TLS module index.
1533
1534unsigned int
1535Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1536 Sized_relobj_file<32, false>* object)
1537{
1538 if (this->got_mod_index_offset_ == -1U)
1539 {
1540 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1541 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1542 Output_data_got<32, false>* got = this->got_section(symtab, layout);
1543 unsigned int got_offset = got->add_constant(0);
1544 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
1545 got_offset);
1546 got->add_constant(0);
1547 this->got_mod_index_offset_ = got_offset;
1548 }
1549 return this->got_mod_index_offset_;
1550}
1551
1552// Optimize the TLS relocation type based on what we know about the
1553// symbol. IS_FINAL is true if the final address of this symbol is
1554// known at link time.
1555
1556tls::Tls_optimization
1557Target_i386::optimize_tls_reloc(bool is_final, int r_type)
1558{
1559 // If we are generating a shared library, then we can't do anything
1560 // in the linker.
1561 if (parameters->options().shared())
1562 return tls::TLSOPT_NONE;
1563
1564 switch (r_type)
1565 {
1566 case elfcpp::R_386_TLS_GD:
1567 case elfcpp::R_386_TLS_GOTDESC:
1568 case elfcpp::R_386_TLS_DESC_CALL:
1569 // These are General-Dynamic which permits fully general TLS
1570 // access. Since we know that we are generating an executable,
1571 // we can convert this to Initial-Exec. If we also know that
1572 // this is a local symbol, we can further switch to Local-Exec.
1573 if (is_final)
1574 return tls::TLSOPT_TO_LE;
1575 return tls::TLSOPT_TO_IE;
1576
1577 case elfcpp::R_386_TLS_LDM:
1578 // This is Local-Dynamic, which refers to a local symbol in the
1579 // dynamic TLS block. Since we know that we generating an
1580 // executable, we can switch to Local-Exec.
1581 return tls::TLSOPT_TO_LE;
1582
1583 case elfcpp::R_386_TLS_LDO_32:
1584 // Another type of Local-Dynamic relocation.
1585 return tls::TLSOPT_TO_LE;
1586
1587 case elfcpp::R_386_TLS_IE:
1588 case elfcpp::R_386_TLS_GOTIE:
1589 case elfcpp::R_386_TLS_IE_32:
1590 // These are Initial-Exec relocs which get the thread offset
1591 // from the GOT. If we know that we are linking against the
1592 // local symbol, we can switch to Local-Exec, which links the
1593 // thread offset into the instruction.
1594 if (is_final)
1595 return tls::TLSOPT_TO_LE;
1596 return tls::TLSOPT_NONE;
1597
1598 case elfcpp::R_386_TLS_LE:
1599 case elfcpp::R_386_TLS_LE_32:
1600 // When we already have Local-Exec, there is nothing further we
1601 // can do.
1602 return tls::TLSOPT_NONE;
1603
1604 default:
1605 gold_unreachable();
1606 }
1607}
1608
1609// Get the Reference_flags for a particular relocation.
1610
1611int
1612Target_i386::Scan::get_reference_flags(unsigned int r_type)
1613{
1614 switch (r_type)
1615 {
1616 case elfcpp::R_386_NONE:
1617 case elfcpp::R_386_GNU_VTINHERIT:
1618 case elfcpp::R_386_GNU_VTENTRY:
1619 case elfcpp::R_386_GOTPC:
1620 // No symbol reference.
1621 return 0;
1622
1623 case elfcpp::R_386_32:
1624 case elfcpp::R_386_16:
1625 case elfcpp::R_386_8:
1626 return Symbol::ABSOLUTE_REF;
1627
1628 case elfcpp::R_386_PC32:
1629 case elfcpp::R_386_PC16:
1630 case elfcpp::R_386_PC8:
1631 case elfcpp::R_386_GOTOFF:
1632 return Symbol::RELATIVE_REF;
1633
1634 case elfcpp::R_386_PLT32:
1635 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1636
1637 case elfcpp::R_386_GOT32:
1638 // Absolute in GOT.
1639 return Symbol::ABSOLUTE_REF;
1640
1641 case elfcpp::R_386_TLS_GD: // Global-dynamic
1642 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1643 case elfcpp::R_386_TLS_DESC_CALL:
1644 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1645 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1646 case elfcpp::R_386_TLS_IE: // Initial-exec
1647 case elfcpp::R_386_TLS_IE_32:
1648 case elfcpp::R_386_TLS_GOTIE:
1649 case elfcpp::R_386_TLS_LE: // Local-exec
1650 case elfcpp::R_386_TLS_LE_32:
1651 return Symbol::TLS_REF;
1652
1653 case elfcpp::R_386_COPY:
1654 case elfcpp::R_386_GLOB_DAT:
1655 case elfcpp::R_386_JUMP_SLOT:
1656 case elfcpp::R_386_RELATIVE:
1657 case elfcpp::R_386_IRELATIVE:
1658 case elfcpp::R_386_TLS_TPOFF:
1659 case elfcpp::R_386_TLS_DTPMOD32:
1660 case elfcpp::R_386_TLS_DTPOFF32:
1661 case elfcpp::R_386_TLS_TPOFF32:
1662 case elfcpp::R_386_TLS_DESC:
1663 case elfcpp::R_386_32PLT:
1664 case elfcpp::R_386_TLS_GD_32:
1665 case elfcpp::R_386_TLS_GD_PUSH:
1666 case elfcpp::R_386_TLS_GD_CALL:
1667 case elfcpp::R_386_TLS_GD_POP:
1668 case elfcpp::R_386_TLS_LDM_32:
1669 case elfcpp::R_386_TLS_LDM_PUSH:
1670 case elfcpp::R_386_TLS_LDM_CALL:
1671 case elfcpp::R_386_TLS_LDM_POP:
1672 case elfcpp::R_386_USED_BY_INTEL_200:
1673 default:
1674 // Not expected. We will give an error later.
1675 return 0;
1676 }
1677}
1678
1679// Report an unsupported relocation against a local symbol.
1680
1681void
1682Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
1683 unsigned int r_type)
1684{
1685 gold_error(_("%s: unsupported reloc %u against local symbol"),
1686 object->name().c_str(), r_type);
1687}
1688
1689// Return whether we need to make a PLT entry for a relocation of a
1690// given type against a STT_GNU_IFUNC symbol.
1691
1692bool
1693Target_i386::Scan::reloc_needs_plt_for_ifunc(
1694 Sized_relobj_file<32, false>* object,
1695 unsigned int r_type)
1696{
1697 int flags = Scan::get_reference_flags(r_type);
1698 if (flags & Symbol::TLS_REF)
1699 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1700 object->name().c_str(), r_type);
1701 return flags != 0;
1702}
1703
1704// Scan a relocation for a local symbol.
1705
1706inline void
1707Target_i386::Scan::local(Symbol_table* symtab,
1708 Layout* layout,
1709 Target_i386* target,
1710 Sized_relobj_file<32, false>* object,
1711 unsigned int data_shndx,
1712 Output_section* output_section,
1713 const elfcpp::Rel<32, false>& reloc,
1714 unsigned int r_type,
1715 const elfcpp::Sym<32, false>& lsym,
1716 bool is_discarded)
1717{
1718 if (is_discarded)
1719 return;
1720
1721 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1722 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1723 && this->reloc_needs_plt_for_ifunc(object, r_type))
1724 {
1725 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1726 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1727 }
1728
1729 switch (r_type)
1730 {
1731 case elfcpp::R_386_NONE:
1732 case elfcpp::R_386_GNU_VTINHERIT:
1733 case elfcpp::R_386_GNU_VTENTRY:
1734 break;
1735
1736 case elfcpp::R_386_32:
1737 // If building a shared library (or a position-independent
1738 // executable), we need to create a dynamic relocation for
1739 // this location. The relocation applied at link time will
1740 // apply the link-time value, so we flag the location with
1741 // an R_386_RELATIVE relocation so the dynamic loader can
1742 // relocate it easily.
1743 if (parameters->options().output_is_position_independent())
1744 {
1745 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1746 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1747 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1748 output_section, data_shndx,
1749 reloc.get_r_offset());
1750 }
1751 break;
1752
1753 case elfcpp::R_386_16:
1754 case elfcpp::R_386_8:
1755 // If building a shared library (or a position-independent
1756 // executable), we need to create a dynamic relocation for
1757 // this location. Because the addend needs to remain in the
1758 // data section, we need to be careful not to apply this
1759 // relocation statically.
1760 if (parameters->options().output_is_position_independent())
1761 {
1762 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1763 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1764 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1765 rel_dyn->add_local(object, r_sym, r_type, output_section,
1766 data_shndx, reloc.get_r_offset());
1767 else
1768 {
1769 gold_assert(lsym.get_st_value() == 0);
1770 unsigned int shndx = lsym.get_st_shndx();
1771 bool is_ordinary;
1772 shndx = object->adjust_sym_shndx(r_sym, shndx,
1773 &is_ordinary);
1774 if (!is_ordinary)
1775 object->error(_("section symbol %u has bad shndx %u"),
1776 r_sym, shndx);
1777 else
1778 rel_dyn->add_local_section(object, shndx,
1779 r_type, output_section,
1780 data_shndx, reloc.get_r_offset());
1781 }
1782 }
1783 break;
1784
1785 case elfcpp::R_386_PC32:
1786 case elfcpp::R_386_PC16:
1787 case elfcpp::R_386_PC8:
1788 break;
1789
1790 case elfcpp::R_386_PLT32:
1791 // Since we know this is a local symbol, we can handle this as a
1792 // PC32 reloc.
1793 break;
1794
1795 case elfcpp::R_386_GOTOFF:
1796 case elfcpp::R_386_GOTPC:
1797 // We need a GOT section.
1798 target->got_section(symtab, layout);
1799 break;
1800
1801 case elfcpp::R_386_GOT32:
1802 {
1803 // The symbol requires a GOT entry.
1804 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1805 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1806
1807 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1808 // lets function pointers compare correctly with shared
1809 // libraries. Otherwise we would need an IRELATIVE reloc.
1810 bool is_new;
1811 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1812 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1813 else
1814 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1815 if (is_new)
1816 {
1817 // If we are generating a shared object, we need to add a
1818 // dynamic RELATIVE relocation for this symbol's GOT entry.
1819 if (parameters->options().output_is_position_independent())
1820 {
1821 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1822 unsigned int got_offset =
1823 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1824 rel_dyn->add_local_relative(object, r_sym,
1825 elfcpp::R_386_RELATIVE,
1826 got, got_offset);
1827 }
1828 }
1829 }
1830 break;
1831
1832 // These are relocations which should only be seen by the
1833 // dynamic linker, and should never be seen here.
1834 case elfcpp::R_386_COPY:
1835 case elfcpp::R_386_GLOB_DAT:
1836 case elfcpp::R_386_JUMP_SLOT:
1837 case elfcpp::R_386_RELATIVE:
1838 case elfcpp::R_386_IRELATIVE:
1839 case elfcpp::R_386_TLS_TPOFF:
1840 case elfcpp::R_386_TLS_DTPMOD32:
1841 case elfcpp::R_386_TLS_DTPOFF32:
1842 case elfcpp::R_386_TLS_TPOFF32:
1843 case elfcpp::R_386_TLS_DESC:
1844 gold_error(_("%s: unexpected reloc %u in object file"),
1845 object->name().c_str(), r_type);
1846 break;
1847
1848 // These are initial TLS relocs, which are expected when
1849 // linking.
1850 case elfcpp::R_386_TLS_GD: // Global-dynamic
1851 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1852 case elfcpp::R_386_TLS_DESC_CALL:
1853 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1854 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1855 case elfcpp::R_386_TLS_IE: // Initial-exec
1856 case elfcpp::R_386_TLS_IE_32:
1857 case elfcpp::R_386_TLS_GOTIE:
1858 case elfcpp::R_386_TLS_LE: // Local-exec
1859 case elfcpp::R_386_TLS_LE_32:
1860 {
1861 bool output_is_shared = parameters->options().shared();
1862 const tls::Tls_optimization optimized_type
1863 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1864 switch (r_type)
1865 {
1866 case elfcpp::R_386_TLS_GD: // Global-dynamic
1867 if (optimized_type == tls::TLSOPT_NONE)
1868 {
1869 // Create a pair of GOT entries for the module index and
1870 // dtv-relative offset.
1871 Output_data_got<32, false>* got
1872 = target->got_section(symtab, layout);
1873 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1874 unsigned int shndx = lsym.get_st_shndx();
1875 bool is_ordinary;
1876 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1877 if (!is_ordinary)
1878 object->error(_("local symbol %u has bad shndx %u"),
1879 r_sym, shndx);
1880 else
1881 got->add_local_pair_with_rel(object, r_sym, shndx,
1882 GOT_TYPE_TLS_PAIR,
1883 target->rel_dyn_section(layout),
1884 elfcpp::R_386_TLS_DTPMOD32);
1885 }
1886 else if (optimized_type != tls::TLSOPT_TO_LE)
1887 unsupported_reloc_local(object, r_type);
1888 break;
1889
1890 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1891 target->define_tls_base_symbol(symtab, layout);
1892 if (optimized_type == tls::TLSOPT_NONE)
1893 {
1894 // Create a double GOT entry with an R_386_TLS_DESC
1895 // reloc. The R_386_TLS_DESC reloc is resolved
1896 // lazily, so the GOT entry needs to be in an area in
1897 // .got.plt, not .got. Call got_section to make sure
1898 // the section has been created.
1899 target->got_section(symtab, layout);
1900 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1901 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1902 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1903 {
1904 unsigned int got_offset = got->add_constant(0);
1905 // The local symbol value is stored in the second
1906 // GOT entry.
1907 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1908 // That set the GOT offset of the local symbol to
1909 // point to the second entry, but we want it to
1910 // point to the first.
1911 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1912 got_offset);
1913 Reloc_section* rt = target->rel_tls_desc_section(layout);
1914 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1915 }
1916 }
1917 else if (optimized_type != tls::TLSOPT_TO_LE)
1918 unsupported_reloc_local(object, r_type);
1919 break;
1920
1921 case elfcpp::R_386_TLS_DESC_CALL:
1922 break;
1923
1924 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1925 if (optimized_type == tls::TLSOPT_NONE)
1926 {
1927 // Create a GOT entry for the module index.
1928 target->got_mod_index_entry(symtab, layout, object);
1929 }
1930 else if (optimized_type != tls::TLSOPT_TO_LE)
1931 unsupported_reloc_local(object, r_type);
1932 break;
1933
1934 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1935 break;
1936
1937 case elfcpp::R_386_TLS_IE: // Initial-exec
1938 case elfcpp::R_386_TLS_IE_32:
1939 case elfcpp::R_386_TLS_GOTIE:
1940 layout->set_has_static_tls();
1941 if (optimized_type == tls::TLSOPT_NONE)
1942 {
1943 // For the R_386_TLS_IE relocation, we need to create a
1944 // dynamic relocation when building a shared library.
1945 if (r_type == elfcpp::R_386_TLS_IE
1946 && parameters->options().shared())
1947 {
1948 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1949 unsigned int r_sym
1950 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1951 rel_dyn->add_local_relative(object, r_sym,
1952 elfcpp::R_386_RELATIVE,
1953 output_section, data_shndx,
1954 reloc.get_r_offset());
1955 }
1956 // Create a GOT entry for the tp-relative offset.
1957 Output_data_got<32, false>* got
1958 = target->got_section(symtab, layout);
1959 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1960 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1961 ? elfcpp::R_386_TLS_TPOFF32
1962 : elfcpp::R_386_TLS_TPOFF);
1963 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1964 ? GOT_TYPE_TLS_OFFSET
1965 : GOT_TYPE_TLS_NOFFSET);
1966 got->add_local_with_rel(object, r_sym, got_type,
1967 target->rel_dyn_section(layout),
1968 dyn_r_type);
1969 }
1970 else if (optimized_type != tls::TLSOPT_TO_LE)
1971 unsupported_reloc_local(object, r_type);
1972 break;
1973
1974 case elfcpp::R_386_TLS_LE: // Local-exec
1975 case elfcpp::R_386_TLS_LE_32:
1976 layout->set_has_static_tls();
1977 if (output_is_shared)
1978 {
1979 // We need to create a dynamic relocation.
1980 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1981 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1982 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1983 ? elfcpp::R_386_TLS_TPOFF32
1984 : elfcpp::R_386_TLS_TPOFF);
1985 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1986 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1987 data_shndx, reloc.get_r_offset());
1988 }
1989 break;
1990
1991 default:
1992 gold_unreachable();
1993 }
1994 }
1995 break;
1996
1997 case elfcpp::R_386_32PLT:
1998 case elfcpp::R_386_TLS_GD_32:
1999 case elfcpp::R_386_TLS_GD_PUSH:
2000 case elfcpp::R_386_TLS_GD_CALL:
2001 case elfcpp::R_386_TLS_GD_POP:
2002 case elfcpp::R_386_TLS_LDM_32:
2003 case elfcpp::R_386_TLS_LDM_PUSH:
2004 case elfcpp::R_386_TLS_LDM_CALL:
2005 case elfcpp::R_386_TLS_LDM_POP:
2006 case elfcpp::R_386_USED_BY_INTEL_200:
2007 default:
2008 unsupported_reloc_local(object, r_type);
2009 break;
2010 }
2011}
2012
2013// Report an unsupported relocation against a global symbol.
2014
2015void
2016Target_i386::Scan::unsupported_reloc_global(
2017 Sized_relobj_file<32, false>* object,
2018 unsigned int r_type,
2019 Symbol* gsym)
2020{
2021 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2022 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2023}
2024
2025inline bool
2026Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
2027{
2028 switch (r_type)
2029 {
2030 case elfcpp::R_386_32:
2031 case elfcpp::R_386_16:
2032 case elfcpp::R_386_8:
2033 case elfcpp::R_386_GOTOFF:
2034 case elfcpp::R_386_GOT32:
2035 {
2036 return true;
2037 }
2038 default:
2039 return false;
2040 }
2041 return false;
2042}
2043
2044inline bool
2045Target_i386::Scan::local_reloc_may_be_function_pointer(
2046 Symbol_table* ,
2047 Layout* ,
2048 Target_i386* ,
2049 Sized_relobj_file<32, false>* ,
2050 unsigned int ,
2051 Output_section* ,
2052 const elfcpp::Rel<32, false>& ,
2053 unsigned int r_type,
2054 const elfcpp::Sym<32, false>&)
2055{
2056 return possible_function_pointer_reloc(r_type);
2057}
2058
2059inline bool
2060Target_i386::Scan::global_reloc_may_be_function_pointer(
2061 Symbol_table* ,
2062 Layout* ,
2063 Target_i386* ,
2064 Sized_relobj_file<32, false>* ,
2065 unsigned int ,
2066 Output_section* ,
2067 const elfcpp::Rel<32, false>& ,
2068 unsigned int r_type,
2069 Symbol*)
2070{
2071 return possible_function_pointer_reloc(r_type);
2072}
2073
2074// Scan a relocation for a global symbol.
2075
2076inline void
2077Target_i386::Scan::global(Symbol_table* symtab,
2078 Layout* layout,
2079 Target_i386* target,
2080 Sized_relobj_file<32, false>* object,
2081 unsigned int data_shndx,
2082 Output_section* output_section,
2083 const elfcpp::Rel<32, false>& reloc,
2084 unsigned int r_type,
2085 Symbol* gsym)
2086{
2087 // A STT_GNU_IFUNC symbol may require a PLT entry.
2088 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2089 && this->reloc_needs_plt_for_ifunc(object, r_type))
2090 target->make_plt_entry(symtab, layout, gsym);
2091
2092 switch (r_type)
2093 {
2094 case elfcpp::R_386_NONE:
2095 case elfcpp::R_386_GNU_VTINHERIT:
2096 case elfcpp::R_386_GNU_VTENTRY:
2097 break;
2098
2099 case elfcpp::R_386_32:
2100 case elfcpp::R_386_16:
2101 case elfcpp::R_386_8:
2102 {
2103 // Make a PLT entry if necessary.
2104 if (gsym->needs_plt_entry())
2105 {
2106 target->make_plt_entry(symtab, layout, gsym);
2107 // Since this is not a PC-relative relocation, we may be
2108 // taking the address of a function. In that case we need to
2109 // set the entry in the dynamic symbol table to the address of
2110 // the PLT entry.
2111 if (gsym->is_from_dynobj() && !parameters->options().shared())
2112 gsym->set_needs_dynsym_value();
2113 }
2114 // Make a dynamic relocation if necessary.
2115 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2116 {
2117 if (gsym->may_need_copy_reloc())
2118 {
2119 target->copy_reloc(symtab, layout, object,
2120 data_shndx, output_section, gsym, reloc);
2121 }
2122 else if (r_type == elfcpp::R_386_32
2123 && gsym->type() == elfcpp::STT_GNU_IFUNC
2124 && gsym->can_use_relative_reloc(false)
2125 && !gsym->is_from_dynobj()
2126 && !gsym->is_undefined()
2127 && !gsym->is_preemptible())
2128 {
2129 // Use an IRELATIVE reloc for a locally defined
2130 // STT_GNU_IFUNC symbol. This makes a function
2131 // address in a PIE executable match the address in a
2132 // shared library that it links against.
2133 Reloc_section* rel_dyn = target->rel_irelative_section(layout);
2134 rel_dyn->add_symbolless_global_addend(gsym,
2135 elfcpp::R_386_IRELATIVE,
2136 output_section,
2137 object, data_shndx,
2138 reloc.get_r_offset());
2139 }
2140 else if (r_type == elfcpp::R_386_32
2141 && gsym->can_use_relative_reloc(false))
2142 {
2143 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2144 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2145 output_section, object,
2146 data_shndx, reloc.get_r_offset());
2147 }
2148 else
2149 {
2150 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2151 rel_dyn->add_global(gsym, r_type, output_section, object,
2152 data_shndx, reloc.get_r_offset());
2153 }
2154 }
2155 }
2156 break;
2157
2158 case elfcpp::R_386_PC32:
2159 case elfcpp::R_386_PC16:
2160 case elfcpp::R_386_PC8:
2161 {
2162 // Make a PLT entry if necessary.
2163 if (gsym->needs_plt_entry())
2164 {
2165 // These relocations are used for function calls only in
2166 // non-PIC code. For a 32-bit relocation in a shared library,
2167 // we'll need a text relocation anyway, so we can skip the
2168 // PLT entry and let the dynamic linker bind the call directly
2169 // to the target. For smaller relocations, we should use a
2170 // PLT entry to ensure that the call can reach.
2171 if (!parameters->options().shared()
2172 || r_type != elfcpp::R_386_PC32)
2173 target->make_plt_entry(symtab, layout, gsym);
2174 }
2175 // Make a dynamic relocation if necessary.
2176 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2177 {
2178 if (gsym->may_need_copy_reloc())
2179 {
2180 target->copy_reloc(symtab, layout, object,
2181 data_shndx, output_section, gsym, reloc);
2182 }
2183 else
2184 {
2185 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2186 rel_dyn->add_global(gsym, r_type, output_section, object,
2187 data_shndx, reloc.get_r_offset());
2188 }
2189 }
2190 }
2191 break;
2192
2193 case elfcpp::R_386_GOT32:
2194 {
2195 // The symbol requires a GOT entry.
2196 Output_data_got<32, false>* got = target->got_section(symtab, layout);
2197 if (gsym->final_value_is_known())
2198 {
2199 // For a STT_GNU_IFUNC symbol we want the PLT address.
2200 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2201 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2202 else
2203 got->add_global(gsym, GOT_TYPE_STANDARD);
2204 }
2205 else
2206 {
2207 // If this symbol is not fully resolved, we need to add a
2208 // GOT entry with a dynamic relocation.
2209 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2210
2211 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2212 //
2213 // 1) The symbol may be defined in some other module.
2214 //
2215 // 2) We are building a shared library and this is a
2216 // protected symbol; using GLOB_DAT means that the dynamic
2217 // linker can use the address of the PLT in the main
2218 // executable when appropriate so that function address
2219 // comparisons work.
2220 //
2221 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2222 // code, again so that function address comparisons work.
2223 if (gsym->is_from_dynobj()
2224 || gsym->is_undefined()
2225 || gsym->is_preemptible()
2226 || (gsym->visibility() == elfcpp::STV_PROTECTED
2227 && parameters->options().shared())
2228 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2229 && parameters->options().output_is_position_independent()))
2230 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
2231 rel_dyn, elfcpp::R_386_GLOB_DAT);
2232 else
2233 {
2234 // For a STT_GNU_IFUNC symbol we want to write the PLT
2235 // offset into the GOT, so that function pointer
2236 // comparisons work correctly.
2237 bool is_new;
2238 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2239 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2240 else
2241 {
2242 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2243 // Tell the dynamic linker to use the PLT address
2244 // when resolving relocations.
2245 if (gsym->is_from_dynobj()
2246 && !parameters->options().shared())
2247 gsym->set_needs_dynsym_value();
2248 }
2249 if (is_new)
2250 {
2251 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2252 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2253 got, got_off);
2254 }
2255 }
2256 }
2257 }
2258 break;
2259
2260 case elfcpp::R_386_PLT32:
2261 // If the symbol is fully resolved, this is just a PC32 reloc.
2262 // Otherwise we need a PLT entry.
2263 if (gsym->final_value_is_known())
2264 break;
2265 // If building a shared library, we can also skip the PLT entry
2266 // if the symbol is defined in the output file and is protected
2267 // or hidden.
2268 if (gsym->is_defined()
2269 && !gsym->is_from_dynobj()
2270 && !gsym->is_preemptible())
2271 break;
2272 target->make_plt_entry(symtab, layout, gsym);
2273 break;
2274
2275 case elfcpp::R_386_GOTOFF:
2276 case elfcpp::R_386_GOTPC:
2277 // We need a GOT section.
2278 target->got_section(symtab, layout);
2279 break;
2280
2281 // These are relocations which should only be seen by the
2282 // dynamic linker, and should never be seen here.
2283 case elfcpp::R_386_COPY:
2284 case elfcpp::R_386_GLOB_DAT:
2285 case elfcpp::R_386_JUMP_SLOT:
2286 case elfcpp::R_386_RELATIVE:
2287 case elfcpp::R_386_IRELATIVE:
2288 case elfcpp::R_386_TLS_TPOFF:
2289 case elfcpp::R_386_TLS_DTPMOD32:
2290 case elfcpp::R_386_TLS_DTPOFF32:
2291 case elfcpp::R_386_TLS_TPOFF32:
2292 case elfcpp::R_386_TLS_DESC:
2293 gold_error(_("%s: unexpected reloc %u in object file"),
2294 object->name().c_str(), r_type);
2295 break;
2296
2297 // These are initial tls relocs, which are expected when
2298 // linking.
2299 case elfcpp::R_386_TLS_GD: // Global-dynamic
2300 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2301 case elfcpp::R_386_TLS_DESC_CALL:
2302 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2303 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2304 case elfcpp::R_386_TLS_IE: // Initial-exec
2305 case elfcpp::R_386_TLS_IE_32:
2306 case elfcpp::R_386_TLS_GOTIE:
2307 case elfcpp::R_386_TLS_LE: // Local-exec
2308 case elfcpp::R_386_TLS_LE_32:
2309 {
2310 const bool is_final = gsym->final_value_is_known();
2311 const tls::Tls_optimization optimized_type
2312 = Target_i386::optimize_tls_reloc(is_final, r_type);
2313 switch (r_type)
2314 {
2315 case elfcpp::R_386_TLS_GD: // Global-dynamic
2316 if (optimized_type == tls::TLSOPT_NONE)
2317 {
2318 // Create a pair of GOT entries for the module index and
2319 // dtv-relative offset.
2320 Output_data_got<32, false>* got
2321 = target->got_section(symtab, layout);
2322 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2323 target->rel_dyn_section(layout),
2324 elfcpp::R_386_TLS_DTPMOD32,
2325 elfcpp::R_386_TLS_DTPOFF32);
2326 }
2327 else if (optimized_type == tls::TLSOPT_TO_IE)
2328 {
2329 // Create a GOT entry for the tp-relative offset.
2330 Output_data_got<32, false>* got
2331 = target->got_section(symtab, layout);
2332 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2333 target->rel_dyn_section(layout),
2334 elfcpp::R_386_TLS_TPOFF);
2335 }
2336 else if (optimized_type != tls::TLSOPT_TO_LE)
2337 unsupported_reloc_global(object, r_type, gsym);
2338 break;
2339
2340 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
2341 target->define_tls_base_symbol(symtab, layout);
2342 if (optimized_type == tls::TLSOPT_NONE)
2343 {
2344 // Create a double GOT entry with an R_386_TLS_DESC
2345 // reloc. The R_386_TLS_DESC reloc is resolved
2346 // lazily, so the GOT entry needs to be in an area in
2347 // .got.plt, not .got. Call got_section to make sure
2348 // the section has been created.
2349 target->got_section(symtab, layout);
2350 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2351 Reloc_section* rt = target->rel_tls_desc_section(layout);
2352 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2353 elfcpp::R_386_TLS_DESC, 0);
2354 }
2355 else if (optimized_type == tls::TLSOPT_TO_IE)
2356 {
2357 // Create a GOT entry for the tp-relative offset.
2358 Output_data_got<32, false>* got
2359 = target->got_section(symtab, layout);
2360 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2361 target->rel_dyn_section(layout),
2362 elfcpp::R_386_TLS_TPOFF);
2363 }
2364 else if (optimized_type != tls::TLSOPT_TO_LE)
2365 unsupported_reloc_global(object, r_type, gsym);
2366 break;
2367
2368 case elfcpp::R_386_TLS_DESC_CALL:
2369 break;
2370
2371 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2372 if (optimized_type == tls::TLSOPT_NONE)
2373 {
2374 // Create a GOT entry for the module index.
2375 target->got_mod_index_entry(symtab, layout, object);
2376 }
2377 else if (optimized_type != tls::TLSOPT_TO_LE)
2378 unsupported_reloc_global(object, r_type, gsym);
2379 break;
2380
2381 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2382 break;
2383
2384 case elfcpp::R_386_TLS_IE: // Initial-exec
2385 case elfcpp::R_386_TLS_IE_32:
2386 case elfcpp::R_386_TLS_GOTIE:
2387 layout->set_has_static_tls();
2388 if (optimized_type == tls::TLSOPT_NONE)
2389 {
2390 // For the R_386_TLS_IE relocation, we need to create a
2391 // dynamic relocation when building a shared library.
2392 if (r_type == elfcpp::R_386_TLS_IE
2393 && parameters->options().shared())
2394 {
2395 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2396 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2397 output_section, object,
2398 data_shndx,
2399 reloc.get_r_offset());
2400 }
2401 // Create a GOT entry for the tp-relative offset.
2402 Output_data_got<32, false>* got
2403 = target->got_section(symtab, layout);
2404 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2405 ? elfcpp::R_386_TLS_TPOFF32
2406 : elfcpp::R_386_TLS_TPOFF);
2407 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2408 ? GOT_TYPE_TLS_OFFSET
2409 : GOT_TYPE_TLS_NOFFSET);
2410 got->add_global_with_rel(gsym, got_type,
2411 target->rel_dyn_section(layout),
2412 dyn_r_type);
2413 }
2414 else if (optimized_type != tls::TLSOPT_TO_LE)
2415 unsupported_reloc_global(object, r_type, gsym);
2416 break;
2417
2418 case elfcpp::R_386_TLS_LE: // Local-exec
2419 case elfcpp::R_386_TLS_LE_32:
2420 layout->set_has_static_tls();
2421 if (parameters->options().shared())
2422 {
2423 // We need to create a dynamic relocation.
2424 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2425 ? elfcpp::R_386_TLS_TPOFF32
2426 : elfcpp::R_386_TLS_TPOFF);
2427 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2428 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
2429 data_shndx, reloc.get_r_offset());
2430 }
2431 break;
2432
2433 default:
2434 gold_unreachable();
2435 }
2436 }
2437 break;
2438
2439 case elfcpp::R_386_32PLT:
2440 case elfcpp::R_386_TLS_GD_32:
2441 case elfcpp::R_386_TLS_GD_PUSH:
2442 case elfcpp::R_386_TLS_GD_CALL:
2443 case elfcpp::R_386_TLS_GD_POP:
2444 case elfcpp::R_386_TLS_LDM_32:
2445 case elfcpp::R_386_TLS_LDM_PUSH:
2446 case elfcpp::R_386_TLS_LDM_CALL:
2447 case elfcpp::R_386_TLS_LDM_POP:
2448 case elfcpp::R_386_USED_BY_INTEL_200:
2449 default:
2450 unsupported_reloc_global(object, r_type, gsym);
2451 break;
2452 }
2453}
2454
2455// Process relocations for gc.
2456
2457void
2458Target_i386::gc_process_relocs(Symbol_table* symtab,
2459 Layout* layout,
2460 Sized_relobj_file<32, false>* object,
2461 unsigned int data_shndx,
2462 unsigned int,
2463 const unsigned char* prelocs,
2464 size_t reloc_count,
2465 Output_section* output_section,
2466 bool needs_special_offset_handling,
2467 size_t local_symbol_count,
2468 const unsigned char* plocal_symbols)
2469{
2470 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2471 Target_i386::Scan,
2472 Target_i386::Relocatable_size_for_reloc>(
2473 symtab,
2474 layout,
2475 this,
2476 object,
2477 data_shndx,
2478 prelocs,
2479 reloc_count,
2480 output_section,
2481 needs_special_offset_handling,
2482 local_symbol_count,
2483 plocal_symbols);
2484}
2485
2486// Scan relocations for a section.
2487
2488void
2489Target_i386::scan_relocs(Symbol_table* symtab,
2490 Layout* layout,
2491 Sized_relobj_file<32, false>* object,
2492 unsigned int data_shndx,
2493 unsigned int sh_type,
2494 const unsigned char* prelocs,
2495 size_t reloc_count,
2496 Output_section* output_section,
2497 bool needs_special_offset_handling,
2498 size_t local_symbol_count,
2499 const unsigned char* plocal_symbols)
2500{
2501 if (sh_type == elfcpp::SHT_RELA)
2502 {
2503 gold_error(_("%s: unsupported RELA reloc section"),
2504 object->name().c_str());
2505 return;
2506 }
2507
2508 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2509 Target_i386::Scan>(
2510 symtab,
2511 layout,
2512 this,
2513 object,
2514 data_shndx,
2515 prelocs,
2516 reloc_count,
2517 output_section,
2518 needs_special_offset_handling,
2519 local_symbol_count,
2520 plocal_symbols);
2521}
2522
2523// Finalize the sections.
2524
2525void
2526Target_i386::do_finalize_sections(
2527 Layout* layout,
2528 const Input_objects*,
2529 Symbol_table* symtab)
2530{
2531 const Reloc_section* rel_plt = (this->plt_ == NULL
2532 ? NULL
2533 : this->plt_->rel_plt());
2534 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
2535 this->rel_dyn_, true, false);
2536
2537 // Emit any relocs we saved in an attempt to avoid generating COPY
2538 // relocs.
2539 if (this->copy_relocs_.any_saved_relocs())
2540 this->copy_relocs_.emit(this->rel_dyn_section(layout));
2541
2542 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2543 // the .got.plt section.
2544 Symbol* sym = this->global_offset_table_;
2545 if (sym != NULL)
2546 {
2547 uint32_t data_size = this->got_plt_->current_data_size();
2548 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
2549 }
2550
2551 if (parameters->doing_static_link()
2552 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2553 {
2554 // If linking statically, make sure that the __rel_iplt symbols
2555 // were defined if necessary, even if we didn't create a PLT.
2556 static const Define_symbol_in_segment syms[] =
2557 {
2558 {
2559 "__rel_iplt_start", // name
2560 elfcpp::PT_LOAD, // segment_type
2561 elfcpp::PF_W, // segment_flags_set
2562 elfcpp::PF(0), // segment_flags_clear
2563 0, // value
2564 0, // size
2565 elfcpp::STT_NOTYPE, // type
2566 elfcpp::STB_GLOBAL, // binding
2567 elfcpp::STV_HIDDEN, // visibility
2568 0, // nonvis
2569 Symbol::SEGMENT_START, // offset_from_base
2570 true // only_if_ref
2571 },
2572 {
2573 "__rel_iplt_end", // name
2574 elfcpp::PT_LOAD, // segment_type
2575 elfcpp::PF_W, // segment_flags_set
2576 elfcpp::PF(0), // segment_flags_clear
2577 0, // value
2578 0, // size
2579 elfcpp::STT_NOTYPE, // type
2580 elfcpp::STB_GLOBAL, // binding
2581 elfcpp::STV_HIDDEN, // visibility
2582 0, // nonvis
2583 Symbol::SEGMENT_START, // offset_from_base
2584 true // only_if_ref
2585 }
2586 };
2587
2588 symtab->define_symbols(layout, 2, syms,
2589 layout->script_options()->saw_sections_clause());
2590 }
2591}
2592
2593// Return whether a direct absolute static relocation needs to be applied.
2594// In cases where Scan::local() or Scan::global() has created
2595// a dynamic relocation other than R_386_RELATIVE, the addend
2596// of the relocation is carried in the data, and we must not
2597// apply the static relocation.
2598
2599inline bool
2600Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
2601 unsigned int r_type,
2602 bool is_32bit,
2603 Output_section* output_section)
2604{
2605 // If the output section is not allocated, then we didn't call
2606 // scan_relocs, we didn't create a dynamic reloc, and we must apply
2607 // the reloc here.
2608 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
2609 return true;
2610
2611 int ref_flags = Scan::get_reference_flags(r_type);
2612
2613 // For local symbols, we will have created a non-RELATIVE dynamic
2614 // relocation only if (a) the output is position independent,
2615 // (b) the relocation is absolute (not pc- or segment-relative), and
2616 // (c) the relocation is not 32 bits wide.
2617 if (gsym == NULL)
2618 return !(parameters->options().output_is_position_independent()
2619 && (ref_flags & Symbol::ABSOLUTE_REF)
2620 && !is_32bit);
2621
2622 // For global symbols, we use the same helper routines used in the
2623 // scan pass. If we did not create a dynamic relocation, or if we
2624 // created a RELATIVE dynamic relocation, we should apply the static
2625 // relocation.
2626 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
2627 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
2628 && gsym->can_use_relative_reloc(ref_flags
2629 & Symbol::FUNCTION_CALL);
2630 return !has_dyn || is_rel;
2631}
2632
2633// Perform a relocation.
2634
2635inline bool
2636Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
2637 Target_i386* target,
2638 Output_section* output_section,
2639 size_t relnum,
2640 const elfcpp::Rel<32, false>& rel,
2641 unsigned int r_type,
2642 const Sized_symbol<32>* gsym,
2643 const Symbol_value<32>* psymval,
2644 unsigned char* view,
2645 elfcpp::Elf_types<32>::Elf_Addr address,
2646 section_size_type view_size)
2647{
2648 if (this->skip_call_tls_get_addr_)
2649 {
2650 if ((r_type != elfcpp::R_386_PLT32
2651 && r_type != elfcpp::R_386_PC32)
2652 || gsym == NULL
2653 || strcmp(gsym->name(), "___tls_get_addr") != 0)
2654 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2655 _("missing expected TLS relocation"));
2656 else
2657 {
2658 this->skip_call_tls_get_addr_ = false;
2659 return false;
2660 }
2661 }
2662
2663 if (view == NULL)
2664 return true;
2665
2666 const Sized_relobj_file<32, false>* object = relinfo->object;
2667
2668 // Pick the value to use for symbols defined in shared objects.
2669 Symbol_value<32> symval;
2670 if (gsym != NULL
2671 && gsym->type() == elfcpp::STT_GNU_IFUNC
2672 && r_type == elfcpp::R_386_32
2673 && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
2674 && gsym->can_use_relative_reloc(false)
2675 && !gsym->is_from_dynobj()
2676 && !gsym->is_undefined()
2677 && !gsym->is_preemptible())
2678 {
2679 // In this case we are generating a R_386_IRELATIVE reloc. We
2680 // want to use the real value of the symbol, not the PLT offset.
2681 }
2682 else if (gsym != NULL
2683 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2684 {
2685 symval.set_output_value(target->plt_address_for_global(gsym));
2686 psymval = &symval;
2687 }
2688 else if (gsym == NULL && psymval->is_ifunc_symbol())
2689 {
2690 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2691 if (object->local_has_plt_offset(r_sym))
2692 {
2693 symval.set_output_value(target->plt_address_for_local(object, r_sym));
2694 psymval = &symval;
2695 }
2696 }
2697
2698 // Get the GOT offset if needed.
2699 // The GOT pointer points to the end of the GOT section.
2700 // We need to subtract the size of the GOT section to get
2701 // the actual offset to use in the relocation.
2702 bool have_got_offset = false;
2703 unsigned int got_offset = 0;
2704 switch (r_type)
2705 {
2706 case elfcpp::R_386_GOT32:
2707 if (gsym != NULL)
2708 {
2709 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2710 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
2711 - target->got_size());
2712 }
2713 else
2714 {
2715 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2716 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2717 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2718 - target->got_size());
2719 }
2720 have_got_offset = true;
2721 break;
2722
2723 default:
2724 break;
2725 }
2726
2727 switch (r_type)
2728 {
2729 case elfcpp::R_386_NONE:
2730 case elfcpp::R_386_GNU_VTINHERIT:
2731 case elfcpp::R_386_GNU_VTENTRY:
2732 break;
2733
2734 case elfcpp::R_386_32:
2735 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2736 Relocate_functions<32, false>::rel32(view, object, psymval);
2737 break;
2738
2739 case elfcpp::R_386_PC32:
2740 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2741 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2742 break;
2743
2744 case elfcpp::R_386_16:
2745 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2746 Relocate_functions<32, false>::rel16(view, object, psymval);
2747 break;
2748
2749 case elfcpp::R_386_PC16:
2750 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2751 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
2752 break;
2753
2754 case elfcpp::R_386_8:
2755 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2756 Relocate_functions<32, false>::rel8(view, object, psymval);
2757 break;
2758
2759 case elfcpp::R_386_PC8:
2760 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2761 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
2762 break;
2763
2764 case elfcpp::R_386_PLT32:
2765 gold_assert(gsym == NULL
2766 || gsym->has_plt_offset()
2767 || gsym->final_value_is_known()
2768 || (gsym->is_defined()
2769 && !gsym->is_from_dynobj()
2770 && !gsym->is_preemptible()));
2771 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2772 break;
2773
2774 case elfcpp::R_386_GOT32:
2775 gold_assert(have_got_offset);
2776 Relocate_functions<32, false>::rel32(view, got_offset);
2777 break;
2778
2779 case elfcpp::R_386_GOTOFF:
2780 {
2781 elfcpp::Elf_types<32>::Elf_Addr value;
2782 value = (psymval->value(object, 0)
2783 - target->got_plt_section()->address());
2784 Relocate_functions<32, false>::rel32(view, value);
2785 }
2786 break;
2787
2788 case elfcpp::R_386_GOTPC:
2789 {
2790 elfcpp::Elf_types<32>::Elf_Addr value;
2791 value = target->got_plt_section()->address();
2792 Relocate_functions<32, false>::pcrel32(view, value, address);
2793 }
2794 break;
2795
2796 case elfcpp::R_386_COPY:
2797 case elfcpp::R_386_GLOB_DAT:
2798 case elfcpp::R_386_JUMP_SLOT:
2799 case elfcpp::R_386_RELATIVE:
2800 case elfcpp::R_386_IRELATIVE:
2801 // These are outstanding tls relocs, which are unexpected when
2802 // linking.
2803 case elfcpp::R_386_TLS_TPOFF:
2804 case elfcpp::R_386_TLS_DTPMOD32:
2805 case elfcpp::R_386_TLS_DTPOFF32:
2806 case elfcpp::R_386_TLS_TPOFF32:
2807 case elfcpp::R_386_TLS_DESC:
2808 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2809 _("unexpected reloc %u in object file"),
2810 r_type);
2811 break;
2812
2813 // These are initial tls relocs, which are expected when
2814 // linking.
2815 case elfcpp::R_386_TLS_GD: // Global-dynamic
2816 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2817 case elfcpp::R_386_TLS_DESC_CALL:
2818 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2819 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2820 case elfcpp::R_386_TLS_IE: // Initial-exec
2821 case elfcpp::R_386_TLS_IE_32:
2822 case elfcpp::R_386_TLS_GOTIE:
2823 case elfcpp::R_386_TLS_LE: // Local-exec
2824 case elfcpp::R_386_TLS_LE_32:
2825 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
2826 view, address, view_size);
2827 break;
2828
2829 case elfcpp::R_386_32PLT:
2830 case elfcpp::R_386_TLS_GD_32:
2831 case elfcpp::R_386_TLS_GD_PUSH:
2832 case elfcpp::R_386_TLS_GD_CALL:
2833 case elfcpp::R_386_TLS_GD_POP:
2834 case elfcpp::R_386_TLS_LDM_32:
2835 case elfcpp::R_386_TLS_LDM_PUSH:
2836 case elfcpp::R_386_TLS_LDM_CALL:
2837 case elfcpp::R_386_TLS_LDM_POP:
2838 case elfcpp::R_386_USED_BY_INTEL_200:
2839 default:
2840 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2841 _("unsupported reloc %u"),
2842 r_type);
2843 break;
2844 }
2845
2846 return true;
2847}
2848
2849// Perform a TLS relocation.
2850
2851inline void
2852Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
2853 Target_i386* target,
2854 size_t relnum,
2855 const elfcpp::Rel<32, false>& rel,
2856 unsigned int r_type,
2857 const Sized_symbol<32>* gsym,
2858 const Symbol_value<32>* psymval,
2859 unsigned char* view,
2860 elfcpp::Elf_types<32>::Elf_Addr,
2861 section_size_type view_size)
2862{
2863 Output_segment* tls_segment = relinfo->layout->tls_segment();
2864
2865 const Sized_relobj_file<32, false>* object = relinfo->object;
2866
2867 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
2868
2869 const bool is_final = (gsym == NULL
2870 ? !parameters->options().shared()
2871 : gsym->final_value_is_known());
2872 const tls::Tls_optimization optimized_type
2873 = Target_i386::optimize_tls_reloc(is_final, r_type);
2874 switch (r_type)
2875 {
2876 case elfcpp::R_386_TLS_GD: // Global-dynamic
2877 if (optimized_type == tls::TLSOPT_TO_LE)
2878 {
2879 if (tls_segment == NULL)
2880 {
2881 gold_assert(parameters->errors()->error_count() > 0
2882 || issue_undefined_symbol_error(gsym));
2883 return;
2884 }
2885 this->tls_gd_to_le(relinfo, relnum, tls_segment,
2886 rel, r_type, value, view,
2887 view_size);
2888 break;
2889 }
2890 else
2891 {
2892 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2893 ? GOT_TYPE_TLS_NOFFSET
2894 : GOT_TYPE_TLS_PAIR);
2895 unsigned int got_offset;
2896 if (gsym != NULL)
2897 {
2898 gold_assert(gsym->has_got_offset(got_type));
2899 got_offset = gsym->got_offset(got_type) - target->got_size();
2900 }
2901 else
2902 {
2903 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2904 gold_assert(object->local_has_got_offset(r_sym, got_type));
2905 got_offset = (object->local_got_offset(r_sym, got_type)
2906 - target->got_size());
2907 }
2908 if (optimized_type == tls::TLSOPT_TO_IE)
2909 {
2910 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2911 got_offset, view, view_size);
2912 break;
2913 }
2914 else if (optimized_type == tls::TLSOPT_NONE)
2915 {
2916 // Relocate the field with the offset of the pair of GOT
2917 // entries.
2918 Relocate_functions<32, false>::rel32(view, got_offset);
2919 break;
2920 }
2921 }
2922 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2923 _("unsupported reloc %u"),
2924 r_type);
2925 break;
2926
2927 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2928 case elfcpp::R_386_TLS_DESC_CALL:
2929 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2930 if (optimized_type == tls::TLSOPT_TO_LE)
2931 {
2932 if (tls_segment == NULL)
2933 {
2934 gold_assert(parameters->errors()->error_count() > 0
2935 || issue_undefined_symbol_error(gsym));
2936 return;
2937 }
2938 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2939 rel, r_type, value, view,
2940 view_size);
2941 break;
2942 }
2943 else
2944 {
2945 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2946 ? GOT_TYPE_TLS_NOFFSET
2947 : GOT_TYPE_TLS_DESC);
2948 unsigned int got_offset = 0;
2949 if (r_type == elfcpp::R_386_TLS_GOTDESC
2950 && optimized_type == tls::TLSOPT_NONE)
2951 {
2952 // We created GOT entries in the .got.tlsdesc portion of
2953 // the .got.plt section, but the offset stored in the
2954 // symbol is the offset within .got.tlsdesc.
2955 got_offset = (target->got_size()
2956 + target->got_plt_section()->data_size());
2957 }
2958 if (gsym != NULL)
2959 {
2960 gold_assert(gsym->has_got_offset(got_type));
2961 got_offset += gsym->got_offset(got_type) - target->got_size();
2962 }
2963 else
2964 {
2965 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2966 gold_assert(object->local_has_got_offset(r_sym, got_type));
2967 got_offset += (object->local_got_offset(r_sym, got_type)
2968 - target->got_size());
2969 }
2970 if (optimized_type == tls::TLSOPT_TO_IE)
2971 {
2972 if (tls_segment == NULL)
2973 {
2974 gold_assert(parameters->errors()->error_count() > 0
2975 || issue_undefined_symbol_error(gsym));
2976 return;
2977 }
2978 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2979 got_offset, view, view_size);
2980 break;
2981 }
2982 else if (optimized_type == tls::TLSOPT_NONE)
2983 {
2984 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2985 {
2986 // Relocate the field with the offset of the pair of GOT
2987 // entries.
2988 Relocate_functions<32, false>::rel32(view, got_offset);
2989 }
2990 break;
2991 }
2992 }
2993 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2994 _("unsupported reloc %u"),
2995 r_type);
2996 break;
2997
2998 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2999 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
3000 {
3001 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3002 _("both SUN and GNU model "
3003 "TLS relocations"));
3004 break;
3005 }
3006 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3007 if (optimized_type == tls::TLSOPT_TO_LE)
3008 {
3009 if (tls_segment == NULL)
3010 {
3011 gold_assert(parameters->errors()->error_count() > 0
3012 || issue_undefined_symbol_error(gsym));
3013 return;
3014 }
3015 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
3016 value, view, view_size);
3017 break;
3018 }
3019 else if (optimized_type == tls::TLSOPT_NONE)
3020 {
3021 // Relocate the field with the offset of the GOT entry for
3022 // the module index.
3023 unsigned int got_offset;
3024 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3025 - target->got_size());
3026 Relocate_functions<32, false>::rel32(view, got_offset);
3027 break;
3028 }
3029 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3030 _("unsupported reloc %u"),
3031 r_type);
3032 break;
3033
3034 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3035 if (optimized_type == tls::TLSOPT_TO_LE)
3036 {
3037 // This reloc can appear in debugging sections, in which
3038 // case we must not convert to local-exec. We decide what
3039 // to do based on whether the section is marked as
3040 // containing executable code. That is what the GNU linker
3041 // does as well.
3042 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
3043 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
3044 {
3045 if (tls_segment == NULL)
3046 {
3047 gold_assert(parameters->errors()->error_count() > 0
3048 || issue_undefined_symbol_error(gsym));
3049 return;
3050 }
3051 value -= tls_segment->memsz();
3052 }
3053 }
3054 Relocate_functions<32, false>::rel32(view, value);
3055 break;
3056
3057 case elfcpp::R_386_TLS_IE: // Initial-exec
3058 case elfcpp::R_386_TLS_GOTIE:
3059 case elfcpp::R_386_TLS_IE_32:
3060 if (optimized_type == tls::TLSOPT_TO_LE)
3061 {
3062 if (tls_segment == NULL)
3063 {
3064 gold_assert(parameters->errors()->error_count() > 0
3065 || issue_undefined_symbol_error(gsym));
3066 return;
3067 }
3068 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3069 rel, r_type, value, view,
3070 view_size);
3071 break;
3072 }
3073 else if (optimized_type == tls::TLSOPT_NONE)
3074 {
3075 // Relocate the field with the offset of the GOT entry for
3076 // the tp-relative offset of the symbol.
3077 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
3078 ? GOT_TYPE_TLS_OFFSET
3079 : GOT_TYPE_TLS_NOFFSET);
3080 unsigned int got_offset;
3081 if (gsym != NULL)
3082 {
3083 gold_assert(gsym->has_got_offset(got_type));
3084 got_offset = gsym->got_offset(got_type);
3085 }
3086 else
3087 {
3088 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3089 gold_assert(object->local_has_got_offset(r_sym, got_type));
3090 got_offset = object->local_got_offset(r_sym, got_type);
3091 }
3092 // For the R_386_TLS_IE relocation, we need to apply the
3093 // absolute address of the GOT entry.
3094 if (r_type == elfcpp::R_386_TLS_IE)
3095 got_offset += target->got_plt_section()->address();
3096 // All GOT offsets are relative to the end of the GOT.
3097 got_offset -= target->got_size();
3098 Relocate_functions<32, false>::rel32(view, got_offset);
3099 break;
3100 }
3101 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3102 _("unsupported reloc %u"),
3103 r_type);
3104 break;
3105
3106 case elfcpp::R_386_TLS_LE: // Local-exec
3107 // If we're creating a shared library, a dynamic relocation will
3108 // have been created for this location, so do not apply it now.
3109 if (!parameters->options().shared())
3110 {
3111 if (tls_segment == NULL)
3112 {
3113 gold_assert(parameters->errors()->error_count() > 0
3114 || issue_undefined_symbol_error(gsym));
3115 return;
3116 }
3117 value -= tls_segment->memsz();
3118 Relocate_functions<32, false>::rel32(view, value);
3119 }
3120 break;
3121
3122 case elfcpp::R_386_TLS_LE_32:
3123 // If we're creating a shared library, a dynamic relocation will
3124 // have been created for this location, so do not apply it now.
3125 if (!parameters->options().shared())
3126 {
3127 if (tls_segment == NULL)
3128 {
3129 gold_assert(parameters->errors()->error_count() > 0
3130 || issue_undefined_symbol_error(gsym));
3131 return;
3132 }
3133 value = tls_segment->memsz() - value;
3134 Relocate_functions<32, false>::rel32(view, value);
3135 }
3136 break;
3137 }
3138}
3139
3140// Do a relocation in which we convert a TLS General-Dynamic to a
3141// Local-Exec.
3142
3143inline void
3144Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
3145 size_t relnum,
3146 Output_segment* tls_segment,
3147 const elfcpp::Rel<32, false>& rel,
3148 unsigned int,
3149 elfcpp::Elf_types<32>::Elf_Addr value,
3150 unsigned char* view,
3151 section_size_type view_size)
3152{
3153 // leal foo(,%reg,1),%eax; call ___tls_get_addr
3154 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3155 // leal foo(%reg),%eax; call ___tls_get_addr
3156 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3157
3158 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3159 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3160
3161 unsigned char op1 = view[-1];
3162 unsigned char op2 = view[-2];
3163
3164 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3165 op2 == 0x8d || op2 == 0x04);
3166 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3167
3168 int roff = 5;
3169
3170 if (op2 == 0x04)
3171 {
3172 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3173 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3174 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3175 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3176 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3177 }
3178 else
3179 {
3180 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3181 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3182 if (rel.get_r_offset() + 9 < view_size
3183 && view[9] == 0x90)
3184 {
3185 // There is a trailing nop. Use the size byte subl.
3186 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3187 roff = 6;
3188 }
3189 else
3190 {
3191 // Use the five byte subl.
3192 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3193 }
3194 }
3195
3196 value = tls_segment->memsz() - value;
3197 Relocate_functions<32, false>::rel32(view + roff, value);
3198
3199 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3200 // We can skip it.
3201 this->skip_call_tls_get_addr_ = true;
3202}
3203
3204// Do a relocation in which we convert a TLS General-Dynamic to an
3205// Initial-Exec.
3206
3207inline void
3208Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
3209 size_t relnum,
3210 Output_segment*,
3211 const elfcpp::Rel<32, false>& rel,
3212 unsigned int,
3213 elfcpp::Elf_types<32>::Elf_Addr value,
3214 unsigned char* view,
3215 section_size_type view_size)
3216{
3217 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
3218 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3219
3220 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3221 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3222
3223 unsigned char op1 = view[-1];
3224 unsigned char op2 = view[-2];
3225
3226 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3227 op2 == 0x8d || op2 == 0x04);
3228 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3229
3230 int roff = 5;
3231
3232 // FIXME: For now, support only the first (SIB) form.
3233 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
3234
3235 if (op2 == 0x04)
3236 {
3237 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3238 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3239 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3240 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3241 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
3242 }
3243 else
3244 {
3245 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3246 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3247 if (rel.get_r_offset() + 9 < view_size
3248 && view[9] == 0x90)
3249 {
3250 // FIXME: This is not the right instruction sequence.
3251 // There is a trailing nop. Use the size byte subl.
3252 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3253 roff = 6;
3254 }
3255 else
3256 {
3257 // FIXME: This is not the right instruction sequence.
3258 // Use the five byte subl.
3259 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3260 }
3261 }
3262
3263 Relocate_functions<32, false>::rel32(view + roff, value);
3264
3265 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3266 // We can skip it.
3267 this->skip_call_tls_get_addr_ = true;
3268}
3269
3270// Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3271// General-Dynamic to a Local-Exec.
3272
3273inline void
3274Target_i386::Relocate::tls_desc_gd_to_le(
3275 const Relocate_info<32, false>* relinfo,
3276 size_t relnum,
3277 Output_segment* tls_segment,
3278 const elfcpp::Rel<32, false>& rel,
3279 unsigned int r_type,
3280 elfcpp::Elf_types<32>::Elf_Addr value,
3281 unsigned char* view,
3282 section_size_type view_size)
3283{
3284 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3285 {
3286 // leal foo@TLSDESC(%ebx), %eax
3287 // ==> leal foo@NTPOFF, %eax
3288 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3289 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3290 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3291 view[-2] == 0x8d && view[-1] == 0x83);
3292 view[-1] = 0x05;
3293 value -= tls_segment->memsz();
3294 Relocate_functions<32, false>::rel32(view, value);
3295 }
3296 else
3297 {
3298 // call *foo@TLSCALL(%eax)
3299 // ==> nop; nop
3300 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3301 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3302 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3303 view[0] == 0xff && view[1] == 0x10);
3304 view[0] = 0x66;
3305 view[1] = 0x90;
3306 }
3307}
3308
3309// Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3310// General-Dynamic to an Initial-Exec.
3311
3312inline void
3313Target_i386::Relocate::tls_desc_gd_to_ie(
3314 const Relocate_info<32, false>* relinfo,
3315 size_t relnum,
3316 Output_segment*,
3317 const elfcpp::Rel<32, false>& rel,
3318 unsigned int r_type,
3319 elfcpp::Elf_types<32>::Elf_Addr value,
3320 unsigned char* view,
3321 section_size_type view_size)
3322{
3323 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3324 {
3325 // leal foo@TLSDESC(%ebx), %eax
3326 // ==> movl foo@GOTNTPOFF(%ebx), %eax
3327 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3328 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3329 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3330 view[-2] == 0x8d && view[-1] == 0x83);
3331 view[-2] = 0x8b;
3332 Relocate_functions<32, false>::rel32(view, value);
3333 }
3334 else
3335 {
3336 // call *foo@TLSCALL(%eax)
3337 // ==> nop; nop
3338 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3339 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3340 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3341 view[0] == 0xff && view[1] == 0x10);
3342 view[0] = 0x66;
3343 view[1] = 0x90;
3344 }
3345}
3346
3347// Do a relocation in which we convert a TLS Local-Dynamic to a
3348// Local-Exec.
3349
3350inline void
3351Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
3352 size_t relnum,
3353 Output_segment*,
3354 const elfcpp::Rel<32, false>& rel,
3355 unsigned int,
3356 elfcpp::Elf_types<32>::Elf_Addr,
3357 unsigned char* view,
3358 section_size_type view_size)
3359{
3360 // leal foo(%reg), %eax; call ___tls_get_addr
3361 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
3362
3363 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3364 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3365
3366 // FIXME: Does this test really always pass?
3367 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3368 view[-2] == 0x8d && view[-1] == 0x83);
3369
3370 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3371
3372 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
3373
3374 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3375 // We can skip it.
3376 this->skip_call_tls_get_addr_ = true;
3377}
3378
3379// Do a relocation in which we convert a TLS Initial-Exec to a
3380// Local-Exec.
3381
3382inline void
3383Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
3384 size_t relnum,
3385 Output_segment* tls_segment,
3386 const elfcpp::Rel<32, false>& rel,
3387 unsigned int r_type,
3388 elfcpp::Elf_types<32>::Elf_Addr value,
3389 unsigned char* view,
3390 section_size_type view_size)
3391{
3392 // We have to actually change the instructions, which means that we
3393 // need to examine the opcodes to figure out which instruction we
3394 // are looking at.
3395 if (r_type == elfcpp::R_386_TLS_IE)
3396 {
3397 // movl %gs:XX,%eax ==> movl $YY,%eax
3398 // movl %gs:XX,%reg ==> movl $YY,%reg
3399 // addl %gs:XX,%reg ==> addl $YY,%reg
3400 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
3401 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3402
3403 unsigned char op1 = view[-1];
3404 if (op1 == 0xa1)
3405 {
3406 // movl XX,%eax ==> movl $YY,%eax
3407 view[-1] = 0xb8;
3408 }
3409 else
3410 {
3411 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3412
3413 unsigned char op2 = view[-2];
3414 if (op2 == 0x8b)
3415 {
3416 // movl XX,%reg ==> movl $YY,%reg
3417 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3418 (op1 & 0xc7) == 0x05);
3419 view[-2] = 0xc7;
3420 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3421 }
3422 else if (op2 == 0x03)
3423 {
3424 // addl XX,%reg ==> addl $YY,%reg
3425 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3426 (op1 & 0xc7) == 0x05);
3427 view[-2] = 0x81;
3428 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3429 }
3430 else
3431 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3432 }
3433 }
3434 else
3435 {
3436 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3437 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3438 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3439 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3440 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3441
3442 unsigned char op1 = view[-1];
3443 unsigned char op2 = view[-2];
3444 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3445 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
3446 if (op2 == 0x8b)
3447 {
3448 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3449 view[-2] = 0xc7;
3450 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3451 }
3452 else if (op2 == 0x2b)
3453 {
3454 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3455 view[-2] = 0x81;
3456 view[-1] = 0xe8 | ((op1 >> 3) & 7);
3457 }
3458 else if (op2 == 0x03)
3459 {
3460 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3461 view[-2] = 0x81;
3462 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3463 }
3464 else
3465 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3466 }
3467
3468 value = tls_segment->memsz() - value;
3469 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
3470 value = - value;
3471
3472 Relocate_functions<32, false>::rel32(view, value);
3473}
3474
3475// Relocate section data.
3476
3477void
3478Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
3479 unsigned int sh_type,
3480 const unsigned char* prelocs,
3481 size_t reloc_count,
3482 Output_section* output_section,
3483 bool needs_special_offset_handling,
3484 unsigned char* view,
3485 elfcpp::Elf_types<32>::Elf_Addr address,
3486 section_size_type view_size,
3487 const Reloc_symbol_changes* reloc_symbol_changes)
3488{
3489 gold_assert(sh_type == elfcpp::SHT_REL);
3490
3491 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
3492 Target_i386::Relocate, gold::Default_comdat_behavior>(
3493 relinfo,
3494 this,
3495 prelocs,
3496 reloc_count,
3497 output_section,
3498 needs_special_offset_handling,
3499 view,
3500 address,
3501 view_size,
3502 reloc_symbol_changes);
3503}
3504
3505// Return the size of a relocation while scanning during a relocatable
3506// link.
3507
3508unsigned int
3509Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
3510 unsigned int r_type,
3511 Relobj* object)
3512{
3513 switch (r_type)
3514 {
3515 case elfcpp::R_386_NONE:
3516 case elfcpp::R_386_GNU_VTINHERIT:
3517 case elfcpp::R_386_GNU_VTENTRY:
3518 case elfcpp::R_386_TLS_GD: // Global-dynamic
3519 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3520 case elfcpp::R_386_TLS_DESC_CALL:
3521 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3522 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3523 case elfcpp::R_386_TLS_IE: // Initial-exec
3524 case elfcpp::R_386_TLS_IE_32:
3525 case elfcpp::R_386_TLS_GOTIE:
3526 case elfcpp::R_386_TLS_LE: // Local-exec
3527 case elfcpp::R_386_TLS_LE_32:
3528 return 0;
3529
3530 case elfcpp::R_386_32:
3531 case elfcpp::R_386_PC32:
3532 case elfcpp::R_386_GOT32:
3533 case elfcpp::R_386_PLT32:
3534 case elfcpp::R_386_GOTOFF:
3535 case elfcpp::R_386_GOTPC:
3536 return 4;
3537
3538 case elfcpp::R_386_16:
3539 case elfcpp::R_386_PC16:
3540 return 2;
3541
3542 case elfcpp::R_386_8:
3543 case elfcpp::R_386_PC8:
3544 return 1;
3545
3546 // These are relocations which should only be seen by the
3547 // dynamic linker, and should never be seen here.
3548 case elfcpp::R_386_COPY:
3549 case elfcpp::R_386_GLOB_DAT:
3550 case elfcpp::R_386_JUMP_SLOT:
3551 case elfcpp::R_386_RELATIVE:
3552 case elfcpp::R_386_IRELATIVE:
3553 case elfcpp::R_386_TLS_TPOFF:
3554 case elfcpp::R_386_TLS_DTPMOD32:
3555 case elfcpp::R_386_TLS_DTPOFF32:
3556 case elfcpp::R_386_TLS_TPOFF32:
3557 case elfcpp::R_386_TLS_DESC:
3558 object->error(_("unexpected reloc %u in object file"), r_type);
3559 return 0;
3560
3561 case elfcpp::R_386_32PLT:
3562 case elfcpp::R_386_TLS_GD_32:
3563 case elfcpp::R_386_TLS_GD_PUSH:
3564 case elfcpp::R_386_TLS_GD_CALL:
3565 case elfcpp::R_386_TLS_GD_POP:
3566 case elfcpp::R_386_TLS_LDM_32:
3567 case elfcpp::R_386_TLS_LDM_PUSH:
3568 case elfcpp::R_386_TLS_LDM_CALL:
3569 case elfcpp::R_386_TLS_LDM_POP:
3570 case elfcpp::R_386_USED_BY_INTEL_200:
3571 default:
3572 object->error(_("unsupported reloc %u in object file"), r_type);
3573 return 0;
3574 }
3575}
3576
3577// Scan the relocs during a relocatable link.
3578
3579void
3580Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
3581 Layout* layout,
3582 Sized_relobj_file<32, false>* object,
3583 unsigned int data_shndx,
3584 unsigned int sh_type,
3585 const unsigned char* prelocs,
3586 size_t reloc_count,
3587 Output_section* output_section,
3588 bool needs_special_offset_handling,
3589 size_t local_symbol_count,
3590 const unsigned char* plocal_symbols,
3591 Relocatable_relocs* rr)
3592{
3593 gold_assert(sh_type == elfcpp::SHT_REL);
3594
3595 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
3596 Relocatable_size_for_reloc> Scan_relocatable_relocs;
3597
3598 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
3599 Scan_relocatable_relocs>(
3600 symtab,
3601 layout,
3602 object,
3603 data_shndx,
3604 prelocs,
3605 reloc_count,
3606 output_section,
3607 needs_special_offset_handling,
3608 local_symbol_count,
3609 plocal_symbols,
3610 rr);
3611}
3612
3613// Emit relocations for a section.
3614
3615void
3616Target_i386::relocate_relocs(
3617 const Relocate_info<32, false>* relinfo,
3618 unsigned int sh_type,
3619 const unsigned char* prelocs,
3620 size_t reloc_count,
3621 Output_section* output_section,
3622 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
3623 const Relocatable_relocs* rr,
3624 unsigned char* view,
3625 elfcpp::Elf_types<32>::Elf_Addr view_address,
3626 section_size_type view_size,
3627 unsigned char* reloc_view,
3628 section_size_type reloc_view_size)
3629{
3630 gold_assert(sh_type == elfcpp::SHT_REL);
3631
3632 gold::relocate_relocs<32, false, elfcpp::SHT_REL>(
3633 relinfo,
3634 prelocs,
3635 reloc_count,
3636 output_section,
3637 offset_in_output_section,
3638 rr,
3639 view,
3640 view_address,
3641 view_size,
3642 reloc_view,
3643 reloc_view_size);
3644}
3645
3646// Return the value to use for a dynamic which requires special
3647// treatment. This is how we support equality comparisons of function
3648// pointers across shared library boundaries, as described in the
3649// processor specific ABI supplement.
3650
3651uint64_t
3652Target_i386::do_dynsym_value(const Symbol* gsym) const
3653{
3654 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3655 return this->plt_address_for_global(gsym);
3656}
3657
3658// Return a string used to fill a code section with nops to take up
3659// the specified length.
3660
3661std::string
3662Target_i386::do_code_fill(section_size_type length) const
3663{
3664 if (length >= 16)
3665 {
3666 // Build a jmp instruction to skip over the bytes.
3667 unsigned char jmp[5];
3668 jmp[0] = 0xe9;
3669 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3670 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3671 + std::string(length - 5, static_cast<char>(0x90)));
3672 }
3673
3674 // Nop sequences of various lengths.
3675 const char nop1[1] = { '\x90' }; // nop
3676 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
3677 const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi
3678 const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3679 '\x00'};
3680 const char nop5[5] = { '\x90', '\x8d', '\x74', // nop
3681 '\x26', '\x00' }; // leal 0(%esi,1),%esi
3682 const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3683 '\x00', '\x00', '\x00' };
3684 const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3685 '\x00', '\x00', '\x00',
3686 '\x00' };
3687 const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop
3688 '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi
3689 '\x00', '\x00' };
3690 const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi
3691 '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi
3692 '\x00', '\x00', '\x00' };
3693 const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi
3694 '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi
3695 '\x00', '\x00', '\x00',
3696 '\x00' };
3697 const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3698 '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi
3699 '\x27', '\x00', '\x00',
3700 '\x00', '\x00' };
3701 const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3702 '\x00', '\x00', '\x00', // leal 0L(%edi),%edi
3703 '\x8d', '\xbf', '\x00',
3704 '\x00', '\x00', '\x00' };
3705 const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3706 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3707 '\x8d', '\xbc', '\x27',
3708 '\x00', '\x00', '\x00',
3709 '\x00' };
3710 const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3711 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3712 '\x00', '\x8d', '\xbc',
3713 '\x27', '\x00', '\x00',
3714 '\x00', '\x00' };
3715 const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15
3716 '\x90', '\x90', '\x90', // nop,nop,nop,...
3717 '\x90', '\x90', '\x90',
3718 '\x90', '\x90', '\x90',
3719 '\x90', '\x90', '\x90' };
3720
3721 const char* nops[16] = {
3722 NULL,
3723 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3724 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3725 };
3726
3727 return std::string(nops[length], length);
3728}
3729
3730// Return the value to use for the base of a DW_EH_PE_datarel offset
3731// in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3732// assembler can not write out the difference between two labels in
3733// different sections, so instead of using a pc-relative value they