Fix support for i386 TLS GD-to-IE optimization.
[deliverable/binutils-gdb.git] / gold / i386.cc
1 // i386.cc -- i386 target support for gold.
2
3 // Copyright (C) 2006-2015 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26
27 #include "elfcpp.h"
28 #include "dwarf.h"
29 #include "parameters.h"
30 #include "reloc.h"
31 #include "i386.h"
32 #include "object.h"
33 #include "symtab.h"
34 #include "layout.h"
35 #include "output.h"
36 #include "copy-relocs.h"
37 #include "target.h"
38 #include "target-reloc.h"
39 #include "target-select.h"
40 #include "tls.h"
41 #include "freebsd.h"
42 #include "nacl.h"
43 #include "gc.h"
44
45 namespace
46 {
47
48 using namespace gold;
49
50 // A class to handle the .got.plt section.
51
52 class Output_data_got_plt_i386 : public Output_section_data_build
53 {
54 public:
55 Output_data_got_plt_i386(Layout* layout)
56 : Output_section_data_build(4),
57 layout_(layout)
58 { }
59
60 protected:
61 // Write out the PLT data.
62 void
63 do_write(Output_file*);
64
65 // Write to a map file.
66 void
67 do_print_to_mapfile(Mapfile* mapfile) const
68 { mapfile->print_output_data(this, "** GOT PLT"); }
69
70 private:
71 // A pointer to the Layout class, so that we can find the .dynamic
72 // section when we write out the GOT PLT section.
73 Layout* layout_;
74 };
75
76 // A class to handle the PLT data.
77 // This is an abstract base class that handles most of the linker details
78 // but does not know the actual contents of PLT entries. The derived
79 // classes below fill in those details.
80
81 class Output_data_plt_i386 : public Output_section_data
82 {
83 public:
84 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
85
86 Output_data_plt_i386(Layout*, uint64_t addralign,
87 Output_data_got_plt_i386*, Output_data_space*);
88
89 // Add an entry to the PLT.
90 void
91 add_entry(Symbol_table*, Layout*, Symbol* gsym);
92
93 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
94 unsigned int
95 add_local_ifunc_entry(Symbol_table*, Layout*,
96 Sized_relobj_file<32, false>* relobj,
97 unsigned int local_sym_index);
98
99 // Return the .rel.plt section data.
100 Reloc_section*
101 rel_plt() const
102 { return this->rel_; }
103
104 // Return where the TLS_DESC relocations should go.
105 Reloc_section*
106 rel_tls_desc(Layout*);
107
108 // Return where the IRELATIVE relocations should go.
109 Reloc_section*
110 rel_irelative(Symbol_table*, Layout*);
111
112 // Return whether we created a section for IRELATIVE relocations.
113 bool
114 has_irelative_section() const
115 { return this->irelative_rel_ != NULL; }
116
117 // Return the number of PLT entries.
118 unsigned int
119 entry_count() const
120 { return this->count_ + this->irelative_count_; }
121
122 // Return the offset of the first non-reserved PLT entry.
123 unsigned int
124 first_plt_entry_offset()
125 { return this->get_plt_entry_size(); }
126
127 // Return the size of a PLT entry.
128 unsigned int
129 get_plt_entry_size() const
130 { return this->do_get_plt_entry_size(); }
131
132 // Return the PLT address to use for a global symbol.
133 uint64_t
134 address_for_global(const Symbol*);
135
136 // Return the PLT address to use for a local symbol.
137 uint64_t
138 address_for_local(const Relobj*, unsigned int symndx);
139
140 // Add .eh_frame information for the PLT.
141 void
142 add_eh_frame(Layout* layout)
143 { this->do_add_eh_frame(layout); }
144
145 protected:
146 // Fill the first PLT entry, given the pointer to the PLT section data
147 // and the runtime address of the GOT.
148 void
149 fill_first_plt_entry(unsigned char* pov,
150 elfcpp::Elf_types<32>::Elf_Addr got_address)
151 { this->do_fill_first_plt_entry(pov, got_address); }
152
153 // Fill a normal PLT entry, given the pointer to the entry's data in the
154 // section, the runtime address of the GOT, the offset into the GOT of
155 // the corresponding slot, the offset into the relocation section of the
156 // corresponding reloc, and the offset of this entry within the whole
157 // PLT. Return the offset from this PLT entry's runtime address that
158 // should be used to compute the initial value of the GOT slot.
159 unsigned int
160 fill_plt_entry(unsigned char* pov,
161 elfcpp::Elf_types<32>::Elf_Addr got_address,
162 unsigned int got_offset,
163 unsigned int plt_offset,
164 unsigned int plt_rel_offset)
165 {
166 return this->do_fill_plt_entry(pov, got_address, got_offset,
167 plt_offset, plt_rel_offset);
168 }
169
170 virtual unsigned int
171 do_get_plt_entry_size() const = 0;
172
173 virtual void
174 do_fill_first_plt_entry(unsigned char* pov,
175 elfcpp::Elf_types<32>::Elf_Addr got_address) = 0;
176
177 virtual unsigned int
178 do_fill_plt_entry(unsigned char* pov,
179 elfcpp::Elf_types<32>::Elf_Addr got_address,
180 unsigned int got_offset,
181 unsigned int plt_offset,
182 unsigned int plt_rel_offset) = 0;
183
184 virtual void
185 do_add_eh_frame(Layout*) = 0;
186
187 void
188 do_adjust_output_section(Output_section* os);
189
190 // Write to a map file.
191 void
192 do_print_to_mapfile(Mapfile* mapfile) const
193 { mapfile->print_output_data(this, _("** PLT")); }
194
195 // The .eh_frame unwind information for the PLT.
196 // The CIE is common across variants of the PLT format.
197 static const int plt_eh_frame_cie_size = 16;
198 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
199
200 private:
201 // Set the final size.
202 void
203 set_final_data_size()
204 {
205 this->set_data_size((this->count_ + this->irelative_count_ + 1)
206 * this->get_plt_entry_size());
207 }
208
209 // Write out the PLT data.
210 void
211 do_write(Output_file*);
212
213 // We keep a list of global STT_GNU_IFUNC symbols, each with its
214 // offset in the GOT.
215 struct Global_ifunc
216 {
217 Symbol* sym;
218 unsigned int got_offset;
219 };
220
221 // We keep a list of local STT_GNU_IFUNC symbols, each with its
222 // offset in the GOT.
223 struct Local_ifunc
224 {
225 Sized_relobj_file<32, false>* object;
226 unsigned int local_sym_index;
227 unsigned int got_offset;
228 };
229
230 // The reloc section.
231 Reloc_section* rel_;
232 // The TLS_DESC relocations, if necessary. These must follow the
233 // regular PLT relocs.
234 Reloc_section* tls_desc_rel_;
235 // The IRELATIVE relocations, if necessary. These must follow the
236 // regular relocatoins and the TLS_DESC relocations.
237 Reloc_section* irelative_rel_;
238 // The .got.plt section.
239 Output_data_got_plt_i386* got_plt_;
240 // The part of the .got.plt section used for IRELATIVE relocs.
241 Output_data_space* got_irelative_;
242 // The number of PLT entries.
243 unsigned int count_;
244 // Number of PLT entries with R_386_IRELATIVE relocs. These follow
245 // the regular PLT entries.
246 unsigned int irelative_count_;
247 // Global STT_GNU_IFUNC symbols.
248 std::vector<Global_ifunc> global_ifuncs_;
249 // Local STT_GNU_IFUNC symbols.
250 std::vector<Local_ifunc> local_ifuncs_;
251 };
252
253 // This is an abstract class for the standard PLT layout.
254 // The derived classes below handle the actual PLT contents
255 // for the executable (non-PIC) and shared-library (PIC) cases.
256 // The unwind information is uniform across those two, so it's here.
257
258 class Output_data_plt_i386_standard : public Output_data_plt_i386
259 {
260 public:
261 Output_data_plt_i386_standard(Layout* layout,
262 Output_data_got_plt_i386* got_plt,
263 Output_data_space* got_irelative)
264 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
265 { }
266
267 protected:
268 virtual unsigned int
269 do_get_plt_entry_size() const
270 { return plt_entry_size; }
271
272 virtual void
273 do_add_eh_frame(Layout* layout)
274 {
275 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
276 plt_eh_frame_fde, plt_eh_frame_fde_size);
277 }
278
279 // The size of an entry in the PLT.
280 static const int plt_entry_size = 16;
281
282 // The .eh_frame unwind information for the PLT.
283 static const int plt_eh_frame_fde_size = 32;
284 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
285 };
286
287 // Actually fill the PLT contents for an executable (non-PIC).
288
289 class Output_data_plt_i386_exec : public Output_data_plt_i386_standard
290 {
291 public:
292 Output_data_plt_i386_exec(Layout* layout,
293 Output_data_got_plt_i386* got_plt,
294 Output_data_space* got_irelative)
295 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
296 { }
297
298 protected:
299 virtual void
300 do_fill_first_plt_entry(unsigned char* pov,
301 elfcpp::Elf_types<32>::Elf_Addr got_address);
302
303 virtual unsigned int
304 do_fill_plt_entry(unsigned char* pov,
305 elfcpp::Elf_types<32>::Elf_Addr got_address,
306 unsigned int got_offset,
307 unsigned int plt_offset,
308 unsigned int plt_rel_offset);
309
310 private:
311 // The first entry in the PLT for an executable.
312 static const unsigned char first_plt_entry[plt_entry_size];
313
314 // Other entries in the PLT for an executable.
315 static const unsigned char plt_entry[plt_entry_size];
316 };
317
318 // Actually fill the PLT contents for a shared library (PIC).
319
320 class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard
321 {
322 public:
323 Output_data_plt_i386_dyn(Layout* layout,
324 Output_data_got_plt_i386* got_plt,
325 Output_data_space* got_irelative)
326 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
327 { }
328
329 protected:
330 virtual void
331 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
332
333 virtual unsigned int
334 do_fill_plt_entry(unsigned char* pov,
335 elfcpp::Elf_types<32>::Elf_Addr,
336 unsigned int got_offset,
337 unsigned int plt_offset,
338 unsigned int plt_rel_offset);
339
340 private:
341 // The first entry in the PLT for a shared object.
342 static const unsigned char first_plt_entry[plt_entry_size];
343
344 // Other entries in the PLT for a shared object.
345 static const unsigned char plt_entry[plt_entry_size];
346 };
347
348 // The i386 target class.
349 // TLS info comes from
350 // http://people.redhat.com/drepper/tls.pdf
351 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
352
353 class Target_i386 : public Sized_target<32, false>
354 {
355 public:
356 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
357
358 Target_i386(const Target::Target_info* info = &i386_info)
359 : Sized_target<32, false>(info),
360 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
361 got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL),
362 rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY),
363 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
364 { }
365
366 // Process the relocations to determine unreferenced sections for
367 // garbage collection.
368 void
369 gc_process_relocs(Symbol_table* symtab,
370 Layout* layout,
371 Sized_relobj_file<32, false>* object,
372 unsigned int data_shndx,
373 unsigned int sh_type,
374 const unsigned char* prelocs,
375 size_t reloc_count,
376 Output_section* output_section,
377 bool needs_special_offset_handling,
378 size_t local_symbol_count,
379 const unsigned char* plocal_symbols);
380
381 // Scan the relocations to look for symbol adjustments.
382 void
383 scan_relocs(Symbol_table* symtab,
384 Layout* layout,
385 Sized_relobj_file<32, false>* object,
386 unsigned int data_shndx,
387 unsigned int sh_type,
388 const unsigned char* prelocs,
389 size_t reloc_count,
390 Output_section* output_section,
391 bool needs_special_offset_handling,
392 size_t local_symbol_count,
393 const unsigned char* plocal_symbols);
394
395 // Finalize the sections.
396 void
397 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
398
399 // Return the value to use for a dynamic which requires special
400 // treatment.
401 uint64_t
402 do_dynsym_value(const Symbol*) const;
403
404 // Relocate a section.
405 void
406 relocate_section(const Relocate_info<32, false>*,
407 unsigned int sh_type,
408 const unsigned char* prelocs,
409 size_t reloc_count,
410 Output_section* output_section,
411 bool needs_special_offset_handling,
412 unsigned char* view,
413 elfcpp::Elf_types<32>::Elf_Addr view_address,
414 section_size_type view_size,
415 const Reloc_symbol_changes*);
416
417 // Scan the relocs during a relocatable link.
418 void
419 scan_relocatable_relocs(Symbol_table* symtab,
420 Layout* layout,
421 Sized_relobj_file<32, false>* object,
422 unsigned int data_shndx,
423 unsigned int sh_type,
424 const unsigned char* prelocs,
425 size_t reloc_count,
426 Output_section* output_section,
427 bool needs_special_offset_handling,
428 size_t local_symbol_count,
429 const unsigned char* plocal_symbols,
430 Relocatable_relocs*);
431
432 // Emit relocations for a section.
433 void
434 relocate_relocs(const Relocate_info<32, false>*,
435 unsigned int sh_type,
436 const unsigned char* prelocs,
437 size_t reloc_count,
438 Output_section* output_section,
439 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
440 const Relocatable_relocs*,
441 unsigned char* view,
442 elfcpp::Elf_types<32>::Elf_Addr view_address,
443 section_size_type view_size,
444 unsigned char* reloc_view,
445 section_size_type reloc_view_size);
446
447 // Return a string used to fill a code section with nops.
448 std::string
449 do_code_fill(section_size_type length) const;
450
451 // Return whether SYM is defined by the ABI.
452 bool
453 do_is_defined_by_abi(const Symbol* sym) const
454 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
455
456 // Return whether a symbol name implies a local label. The UnixWare
457 // 2.1 cc generates temporary symbols that start with .X, so we
458 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
459 // If so, we should move the .X recognition into
460 // Target::do_is_local_label_name.
461 bool
462 do_is_local_label_name(const char* name) const
463 {
464 if (name[0] == '.' && name[1] == 'X')
465 return true;
466 return Target::do_is_local_label_name(name);
467 }
468
469 // Return the PLT address to use for a global symbol.
470 uint64_t
471 do_plt_address_for_global(const Symbol* gsym) const
472 { return this->plt_section()->address_for_global(gsym); }
473
474 uint64_t
475 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
476 { return this->plt_section()->address_for_local(relobj, symndx); }
477
478 // We can tell whether we take the address of a function.
479 inline bool
480 do_can_check_for_function_pointers() const
481 { return true; }
482
483 // Return the base for a DW_EH_PE_datarel encoding.
484 uint64_t
485 do_ehframe_datarel_base() const;
486
487 // Return whether SYM is call to a non-split function.
488 bool
489 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
490
491 // Adjust -fsplit-stack code which calls non-split-stack code.
492 void
493 do_calls_non_split(Relobj* object, unsigned int shndx,
494 section_offset_type fnoffset, section_size_type fnsize,
495 unsigned char* view, section_size_type view_size,
496 std::string* from, std::string* to) const;
497
498 // Return the size of the GOT section.
499 section_size_type
500 got_size() const
501 {
502 gold_assert(this->got_ != NULL);
503 return this->got_->data_size();
504 }
505
506 // Return the number of entries in the GOT.
507 unsigned int
508 got_entry_count() const
509 {
510 if (this->got_ == NULL)
511 return 0;
512 return this->got_size() / 4;
513 }
514
515 // Return the number of entries in the PLT.
516 unsigned int
517 plt_entry_count() const;
518
519 // Return the offset of the first non-reserved PLT entry.
520 unsigned int
521 first_plt_entry_offset() const;
522
523 // Return the size of each PLT entry.
524 unsigned int
525 plt_entry_size() const;
526
527 protected:
528 // Instantiate the plt_ member.
529 // This chooses the right PLT flavor for an executable or a shared object.
530 Output_data_plt_i386*
531 make_data_plt(Layout* layout,
532 Output_data_got_plt_i386* got_plt,
533 Output_data_space* got_irelative,
534 bool dyn)
535 { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); }
536
537 virtual Output_data_plt_i386*
538 do_make_data_plt(Layout* layout,
539 Output_data_got_plt_i386* got_plt,
540 Output_data_space* got_irelative,
541 bool dyn)
542 {
543 if (dyn)
544 return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative);
545 else
546 return new Output_data_plt_i386_exec(layout, got_plt, got_irelative);
547 }
548
549 private:
550 // The class which scans relocations.
551 struct Scan
552 {
553 static inline int
554
555 get_reference_flags(unsigned int r_type);
556
557 inline void
558 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
559 Sized_relobj_file<32, false>* object,
560 unsigned int data_shndx,
561 Output_section* output_section,
562 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
563 const elfcpp::Sym<32, false>& lsym,
564 bool is_discarded);
565
566 inline void
567 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
568 Sized_relobj_file<32, false>* object,
569 unsigned int data_shndx,
570 Output_section* output_section,
571 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
572 Symbol* gsym);
573
574 inline bool
575 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
576 Target_i386* target,
577 Sized_relobj_file<32, false>* object,
578 unsigned int data_shndx,
579 Output_section* output_section,
580 const elfcpp::Rel<32, false>& reloc,
581 unsigned int r_type,
582 const elfcpp::Sym<32, false>& lsym);
583
584 inline bool
585 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
586 Target_i386* target,
587 Sized_relobj_file<32, false>* object,
588 unsigned int data_shndx,
589 Output_section* output_section,
590 const elfcpp::Rel<32, false>& reloc,
591 unsigned int r_type,
592 Symbol* gsym);
593
594 inline bool
595 possible_function_pointer_reloc(unsigned int r_type);
596
597 bool
598 reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*,
599 unsigned int r_type);
600
601 static void
602 unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type);
603
604 static void
605 unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type,
606 Symbol*);
607 };
608
609 // The class which implements relocation.
610 class Relocate
611 {
612 public:
613 Relocate()
614 : skip_call_tls_get_addr_(false),
615 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
616 { }
617
618 ~Relocate()
619 {
620 if (this->skip_call_tls_get_addr_)
621 {
622 // FIXME: This needs to specify the location somehow.
623 gold_error(_("missing expected TLS relocation"));
624 }
625 }
626
627 // Return whether the static relocation needs to be applied.
628 inline bool
629 should_apply_static_reloc(const Sized_symbol<32>* gsym,
630 unsigned int r_type,
631 bool is_32bit,
632 Output_section* output_section);
633
634 // Do a relocation. Return false if the caller should not issue
635 // any warnings about this relocation.
636 inline bool
637 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
638 size_t relnum, const elfcpp::Rel<32, false>&,
639 unsigned int r_type, const Sized_symbol<32>*,
640 const Symbol_value<32>*,
641 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
642 section_size_type);
643
644 private:
645 // Do a TLS relocation.
646 inline void
647 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
648 size_t relnum, const elfcpp::Rel<32, false>&,
649 unsigned int r_type, const Sized_symbol<32>*,
650 const Symbol_value<32>*,
651 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
652 section_size_type);
653
654 // Do a TLS General-Dynamic to Initial-Exec transition.
655 inline void
656 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
657 Output_segment* tls_segment,
658 const elfcpp::Rel<32, false>&, unsigned int r_type,
659 elfcpp::Elf_types<32>::Elf_Addr value,
660 unsigned char* view,
661 section_size_type view_size);
662
663 // Do a TLS General-Dynamic to Local-Exec transition.
664 inline void
665 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
666 Output_segment* tls_segment,
667 const elfcpp::Rel<32, false>&, unsigned int r_type,
668 elfcpp::Elf_types<32>::Elf_Addr value,
669 unsigned char* view,
670 section_size_type view_size);
671
672 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
673 // transition.
674 inline void
675 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
676 Output_segment* tls_segment,
677 const elfcpp::Rel<32, false>&, unsigned int r_type,
678 elfcpp::Elf_types<32>::Elf_Addr value,
679 unsigned char* view,
680 section_size_type view_size);
681
682 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
683 // transition.
684 inline void
685 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
686 Output_segment* tls_segment,
687 const elfcpp::Rel<32, false>&, unsigned int r_type,
688 elfcpp::Elf_types<32>::Elf_Addr value,
689 unsigned char* view,
690 section_size_type view_size);
691
692 // Do a TLS Local-Dynamic to Local-Exec transition.
693 inline void
694 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
695 Output_segment* tls_segment,
696 const elfcpp::Rel<32, false>&, unsigned int r_type,
697 elfcpp::Elf_types<32>::Elf_Addr value,
698 unsigned char* view,
699 section_size_type view_size);
700
701 // Do a TLS Initial-Exec to Local-Exec transition.
702 static inline void
703 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
704 Output_segment* tls_segment,
705 const elfcpp::Rel<32, false>&, unsigned int r_type,
706 elfcpp::Elf_types<32>::Elf_Addr value,
707 unsigned char* view,
708 section_size_type view_size);
709
710 // We need to keep track of which type of local dynamic relocation
711 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
712 enum Local_dynamic_type
713 {
714 LOCAL_DYNAMIC_NONE,
715 LOCAL_DYNAMIC_SUN,
716 LOCAL_DYNAMIC_GNU
717 };
718
719 // This is set if we should skip the next reloc, which should be a
720 // PLT32 reloc against ___tls_get_addr.
721 bool skip_call_tls_get_addr_;
722 // The type of local dynamic relocation we have seen in the section
723 // being relocated, if any.
724 Local_dynamic_type local_dynamic_type_;
725 };
726
727 // A class which returns the size required for a relocation type,
728 // used while scanning relocs during a relocatable link.
729 class Relocatable_size_for_reloc
730 {
731 public:
732 unsigned int
733 get_size_for_reloc(unsigned int, Relobj*);
734 };
735
736 // Adjust TLS relocation type based on the options and whether this
737 // is a local symbol.
738 static tls::Tls_optimization
739 optimize_tls_reloc(bool is_final, int r_type);
740
741 // Get the GOT section, creating it if necessary.
742 Output_data_got<32, false>*
743 got_section(Symbol_table*, Layout*);
744
745 // Get the GOT PLT section.
746 Output_data_got_plt_i386*
747 got_plt_section() const
748 {
749 gold_assert(this->got_plt_ != NULL);
750 return this->got_plt_;
751 }
752
753 // Get the GOT section for TLSDESC entries.
754 Output_data_got<32, false>*
755 got_tlsdesc_section() const
756 {
757 gold_assert(this->got_tlsdesc_ != NULL);
758 return this->got_tlsdesc_;
759 }
760
761 // Create the PLT section.
762 void
763 make_plt_section(Symbol_table* symtab, Layout* layout);
764
765 // Create a PLT entry for a global symbol.
766 void
767 make_plt_entry(Symbol_table*, Layout*, Symbol*);
768
769 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
770 void
771 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
772 Sized_relobj_file<32, false>* relobj,
773 unsigned int local_sym_index);
774
775 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
776 void
777 define_tls_base_symbol(Symbol_table*, Layout*);
778
779 // Create a GOT entry for the TLS module index.
780 unsigned int
781 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
782 Sized_relobj_file<32, false>* object);
783
784 // Get the PLT section.
785 Output_data_plt_i386*
786 plt_section() const
787 {
788 gold_assert(this->plt_ != NULL);
789 return this->plt_;
790 }
791
792 // Get the dynamic reloc section, creating it if necessary.
793 Reloc_section*
794 rel_dyn_section(Layout*);
795
796 // Get the section to use for TLS_DESC relocations.
797 Reloc_section*
798 rel_tls_desc_section(Layout*) const;
799
800 // Get the section to use for IRELATIVE relocations.
801 Reloc_section*
802 rel_irelative_section(Layout*);
803
804 // Add a potential copy relocation.
805 void
806 copy_reloc(Symbol_table* symtab, Layout* layout,
807 Sized_relobj_file<32, false>* object,
808 unsigned int shndx, Output_section* output_section,
809 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
810 {
811 this->copy_relocs_.copy_reloc(symtab, layout,
812 symtab->get_sized_symbol<32>(sym),
813 object, shndx, output_section, reloc,
814 this->rel_dyn_section(layout));
815 }
816
817 // Information about this specific target which we pass to the
818 // general Target structure.
819 static const Target::Target_info i386_info;
820
821 // The types of GOT entries needed for this platform.
822 // These values are exposed to the ABI in an incremental link.
823 // Do not renumber existing values without changing the version
824 // number of the .gnu_incremental_inputs section.
825 enum Got_type
826 {
827 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
828 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
829 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
830 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
831 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
832 };
833
834 // The GOT section.
835 Output_data_got<32, false>* got_;
836 // The PLT section.
837 Output_data_plt_i386* plt_;
838 // The GOT PLT section.
839 Output_data_got_plt_i386* got_plt_;
840 // The GOT section for IRELATIVE relocations.
841 Output_data_space* got_irelative_;
842 // The GOT section for TLSDESC relocations.
843 Output_data_got<32, false>* got_tlsdesc_;
844 // The _GLOBAL_OFFSET_TABLE_ symbol.
845 Symbol* global_offset_table_;
846 // The dynamic reloc section.
847 Reloc_section* rel_dyn_;
848 // The section to use for IRELATIVE relocs.
849 Reloc_section* rel_irelative_;
850 // Relocs saved to avoid a COPY reloc.
851 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
852 // Offset of the GOT entry for the TLS module index.
853 unsigned int got_mod_index_offset_;
854 // True if the _TLS_MODULE_BASE_ symbol has been defined.
855 bool tls_base_symbol_defined_;
856 };
857
858 const Target::Target_info Target_i386::i386_info =
859 {
860 32, // size
861 false, // is_big_endian
862 elfcpp::EM_386, // machine_code
863 false, // has_make_symbol
864 false, // has_resolve
865 true, // has_code_fill
866 true, // is_default_stack_executable
867 true, // can_icf_inline_merge_sections
868 '\0', // wrap_char
869 "/usr/lib/libc.so.1", // dynamic_linker
870 0x08048000, // default_text_segment_address
871 0x1000, // abi_pagesize (overridable by -z max-page-size)
872 0x1000, // common_pagesize (overridable by -z common-page-size)
873 false, // isolate_execinstr
874 0, // rosegment_gap
875 elfcpp::SHN_UNDEF, // small_common_shndx
876 elfcpp::SHN_UNDEF, // large_common_shndx
877 0, // small_common_section_flags
878 0, // large_common_section_flags
879 NULL, // attributes_section
880 NULL, // attributes_vendor
881 "_start" // entry_symbol_name
882 };
883
884 // Get the GOT section, creating it if necessary.
885
886 Output_data_got<32, false>*
887 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
888 {
889 if (this->got_ == NULL)
890 {
891 gold_assert(symtab != NULL && layout != NULL);
892
893 this->got_ = new Output_data_got<32, false>();
894
895 // When using -z now, we can treat .got.plt as a relro section.
896 // Without -z now, it is modified after program startup by lazy
897 // PLT relocations.
898 bool is_got_plt_relro = parameters->options().now();
899 Output_section_order got_order = (is_got_plt_relro
900 ? ORDER_RELRO
901 : ORDER_RELRO_LAST);
902 Output_section_order got_plt_order = (is_got_plt_relro
903 ? ORDER_RELRO
904 : ORDER_NON_RELRO_FIRST);
905
906 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
907 (elfcpp::SHF_ALLOC
908 | elfcpp::SHF_WRITE),
909 this->got_, got_order, true);
910
911 this->got_plt_ = new Output_data_got_plt_i386(layout);
912 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
913 (elfcpp::SHF_ALLOC
914 | elfcpp::SHF_WRITE),
915 this->got_plt_, got_plt_order,
916 is_got_plt_relro);
917
918 // The first three entries are reserved.
919 this->got_plt_->set_current_data_size(3 * 4);
920
921 if (!is_got_plt_relro)
922 {
923 // Those bytes can go into the relro segment.
924 layout->increase_relro(3 * 4);
925 }
926
927 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
928 this->global_offset_table_ =
929 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
930 Symbol_table::PREDEFINED,
931 this->got_plt_,
932 0, 0, elfcpp::STT_OBJECT,
933 elfcpp::STB_LOCAL,
934 elfcpp::STV_HIDDEN, 0,
935 false, false);
936
937 // If there are any IRELATIVE relocations, they get GOT entries
938 // in .got.plt after the jump slot relocations.
939 this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT");
940 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
941 (elfcpp::SHF_ALLOC
942 | elfcpp::SHF_WRITE),
943 this->got_irelative_,
944 got_plt_order, is_got_plt_relro);
945
946 // If there are any TLSDESC relocations, they get GOT entries in
947 // .got.plt after the jump slot entries.
948 this->got_tlsdesc_ = new Output_data_got<32, false>();
949 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
950 (elfcpp::SHF_ALLOC
951 | elfcpp::SHF_WRITE),
952 this->got_tlsdesc_,
953 got_plt_order, is_got_plt_relro);
954 }
955
956 return this->got_;
957 }
958
959 // Get the dynamic reloc section, creating it if necessary.
960
961 Target_i386::Reloc_section*
962 Target_i386::rel_dyn_section(Layout* layout)
963 {
964 if (this->rel_dyn_ == NULL)
965 {
966 gold_assert(layout != NULL);
967 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
968 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
969 elfcpp::SHF_ALLOC, this->rel_dyn_,
970 ORDER_DYNAMIC_RELOCS, false);
971 }
972 return this->rel_dyn_;
973 }
974
975 // Get the section to use for IRELATIVE relocs, creating it if
976 // necessary. These go in .rel.dyn, but only after all other dynamic
977 // relocations. They need to follow the other dynamic relocations so
978 // that they can refer to global variables initialized by those
979 // relocs.
980
981 Target_i386::Reloc_section*
982 Target_i386::rel_irelative_section(Layout* layout)
983 {
984 if (this->rel_irelative_ == NULL)
985 {
986 // Make sure we have already create the dynamic reloc section.
987 this->rel_dyn_section(layout);
988 this->rel_irelative_ = new Reloc_section(false);
989 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
990 elfcpp::SHF_ALLOC, this->rel_irelative_,
991 ORDER_DYNAMIC_RELOCS, false);
992 gold_assert(this->rel_dyn_->output_section()
993 == this->rel_irelative_->output_section());
994 }
995 return this->rel_irelative_;
996 }
997
998 // Write the first three reserved words of the .got.plt section.
999 // The remainder of the section is written while writing the PLT
1000 // in Output_data_plt_i386::do_write.
1001
1002 void
1003 Output_data_got_plt_i386::do_write(Output_file* of)
1004 {
1005 // The first entry in the GOT is the address of the .dynamic section
1006 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1007 // We saved space for them when we created the section in
1008 // Target_i386::got_section.
1009 const off_t got_file_offset = this->offset();
1010 gold_assert(this->data_size() >= 12);
1011 unsigned char* const got_view = of->get_output_view(got_file_offset, 12);
1012 Output_section* dynamic = this->layout_->dynamic_section();
1013 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1014 elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr);
1015 memset(got_view + 4, 0, 8);
1016 of->write_output_view(got_file_offset, 12, got_view);
1017 }
1018
1019 // Create the PLT section. The ordinary .got section is an argument,
1020 // since we need to refer to the start. We also create our own .got
1021 // section just for PLT entries.
1022
1023 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
1024 uint64_t addralign,
1025 Output_data_got_plt_i386* got_plt,
1026 Output_data_space* got_irelative)
1027 : Output_section_data(addralign),
1028 tls_desc_rel_(NULL), irelative_rel_(NULL), got_plt_(got_plt),
1029 got_irelative_(got_irelative), count_(0), irelative_count_(0),
1030 global_ifuncs_(), local_ifuncs_()
1031 {
1032 this->rel_ = new Reloc_section(false);
1033 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1034 elfcpp::SHF_ALLOC, this->rel_,
1035 ORDER_DYNAMIC_PLT_RELOCS, false);
1036 }
1037
1038 void
1039 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
1040 {
1041 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
1042 // linker, and so do we.
1043 os->set_entsize(4);
1044 }
1045
1046 // Add an entry to the PLT.
1047
1048 void
1049 Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
1050 Symbol* gsym)
1051 {
1052 gold_assert(!gsym->has_plt_offset());
1053
1054 // Every PLT entry needs a reloc.
1055 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1056 && gsym->can_use_relative_reloc(false))
1057 {
1058 gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size());
1059 ++this->irelative_count_;
1060 section_offset_type got_offset =
1061 this->got_irelative_->current_data_size();
1062 this->got_irelative_->set_current_data_size(got_offset + 4);
1063 Reloc_section* rel = this->rel_irelative(symtab, layout);
1064 rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
1065 this->got_irelative_, got_offset);
1066 struct Global_ifunc gi;
1067 gi.sym = gsym;
1068 gi.got_offset = got_offset;
1069 this->global_ifuncs_.push_back(gi);
1070 }
1071 else
1072 {
1073 // When setting the PLT offset we skip the initial reserved PLT
1074 // entry.
1075 gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size());
1076
1077 ++this->count_;
1078
1079 section_offset_type got_offset = this->got_plt_->current_data_size();
1080
1081 // Every PLT entry needs a GOT entry which points back to the
1082 // PLT entry (this will be changed by the dynamic linker,
1083 // normally lazily when the function is called).
1084 this->got_plt_->set_current_data_size(got_offset + 4);
1085
1086 gsym->set_needs_dynsym_entry();
1087 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
1088 got_offset);
1089 }
1090
1091 // Note that we don't need to save the symbol. The contents of the
1092 // PLT are independent of which symbols are used. The symbols only
1093 // appear in the relocations.
1094 }
1095
1096 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1097 // the PLT offset.
1098
1099 unsigned int
1100 Output_data_plt_i386::add_local_ifunc_entry(
1101 Symbol_table* symtab,
1102 Layout* layout,
1103 Sized_relobj_file<32, false>* relobj,
1104 unsigned int local_sym_index)
1105 {
1106 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1107 ++this->irelative_count_;
1108
1109 section_offset_type got_offset = this->got_irelative_->current_data_size();
1110
1111 // Every PLT entry needs a GOT entry which points back to the PLT
1112 // entry.
1113 this->got_irelative_->set_current_data_size(got_offset + 4);
1114
1115 // Every PLT entry needs a reloc.
1116 Reloc_section* rel = this->rel_irelative(symtab, layout);
1117 rel->add_symbolless_local_addend(relobj, local_sym_index,
1118 elfcpp::R_386_IRELATIVE,
1119 this->got_irelative_, got_offset);
1120
1121 struct Local_ifunc li;
1122 li.object = relobj;
1123 li.local_sym_index = local_sym_index;
1124 li.got_offset = got_offset;
1125 this->local_ifuncs_.push_back(li);
1126
1127 return plt_offset;
1128 }
1129
1130 // Return where the TLS_DESC relocations should go, creating it if
1131 // necessary. These follow the JUMP_SLOT relocations.
1132
1133 Output_data_plt_i386::Reloc_section*
1134 Output_data_plt_i386::rel_tls_desc(Layout* layout)
1135 {
1136 if (this->tls_desc_rel_ == NULL)
1137 {
1138 this->tls_desc_rel_ = new Reloc_section(false);
1139 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1140 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
1141 ORDER_DYNAMIC_PLT_RELOCS, false);
1142 gold_assert(this->tls_desc_rel_->output_section()
1143 == this->rel_->output_section());
1144 }
1145 return this->tls_desc_rel_;
1146 }
1147
1148 // Return where the IRELATIVE relocations should go in the PLT. These
1149 // follow the JUMP_SLOT and TLS_DESC relocations.
1150
1151 Output_data_plt_i386::Reloc_section*
1152 Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
1153 {
1154 if (this->irelative_rel_ == NULL)
1155 {
1156 // Make sure we have a place for the TLS_DESC relocations, in
1157 // case we see any later on.
1158 this->rel_tls_desc(layout);
1159 this->irelative_rel_ = new Reloc_section(false);
1160 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1161 elfcpp::SHF_ALLOC, this->irelative_rel_,
1162 ORDER_DYNAMIC_PLT_RELOCS, false);
1163 gold_assert(this->irelative_rel_->output_section()
1164 == this->rel_->output_section());
1165
1166 if (parameters->doing_static_link())
1167 {
1168 // A statically linked executable will only have a .rel.plt
1169 // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
1170 // symbols. The library will use these symbols to locate
1171 // the IRELATIVE relocs at program startup time.
1172 symtab->define_in_output_data("__rel_iplt_start", NULL,
1173 Symbol_table::PREDEFINED,
1174 this->irelative_rel_, 0, 0,
1175 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1176 elfcpp::STV_HIDDEN, 0, false, true);
1177 symtab->define_in_output_data("__rel_iplt_end", NULL,
1178 Symbol_table::PREDEFINED,
1179 this->irelative_rel_, 0, 0,
1180 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1181 elfcpp::STV_HIDDEN, 0, true, true);
1182 }
1183 }
1184 return this->irelative_rel_;
1185 }
1186
1187 // Return the PLT address to use for a global symbol.
1188
1189 uint64_t
1190 Output_data_plt_i386::address_for_global(const Symbol* gsym)
1191 {
1192 uint64_t offset = 0;
1193 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1194 && gsym->can_use_relative_reloc(false))
1195 offset = (this->count_ + 1) * this->get_plt_entry_size();
1196 return this->address() + offset + gsym->plt_offset();
1197 }
1198
1199 // Return the PLT address to use for a local symbol. These are always
1200 // IRELATIVE relocs.
1201
1202 uint64_t
1203 Output_data_plt_i386::address_for_local(const Relobj* object,
1204 unsigned int r_sym)
1205 {
1206 return (this->address()
1207 + (this->count_ + 1) * this->get_plt_entry_size()
1208 + object->local_plt_offset(r_sym));
1209 }
1210
1211 // The first entry in the PLT for an executable.
1212
1213 const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] =
1214 {
1215 0xff, 0x35, // pushl contents of memory address
1216 0, 0, 0, 0, // replaced with address of .got + 4
1217 0xff, 0x25, // jmp indirect
1218 0, 0, 0, 0, // replaced with address of .got + 8
1219 0, 0, 0, 0 // unused
1220 };
1221
1222 void
1223 Output_data_plt_i386_exec::do_fill_first_plt_entry(
1224 unsigned char* pov,
1225 elfcpp::Elf_types<32>::Elf_Addr got_address)
1226 {
1227 memcpy(pov, first_plt_entry, plt_entry_size);
1228 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
1229 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
1230 }
1231
1232 // The first entry in the PLT for a shared object.
1233
1234 const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] =
1235 {
1236 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
1237 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
1238 0, 0, 0, 0 // unused
1239 };
1240
1241 void
1242 Output_data_plt_i386_dyn::do_fill_first_plt_entry(
1243 unsigned char* pov,
1244 elfcpp::Elf_types<32>::Elf_Addr)
1245 {
1246 memcpy(pov, first_plt_entry, plt_entry_size);
1247 }
1248
1249 // Subsequent entries in the PLT for an executable.
1250
1251 const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] =
1252 {
1253 0xff, 0x25, // jmp indirect
1254 0, 0, 0, 0, // replaced with address of symbol in .got
1255 0x68, // pushl immediate
1256 0, 0, 0, 0, // replaced with offset into relocation table
1257 0xe9, // jmp relative
1258 0, 0, 0, 0 // replaced with offset to start of .plt
1259 };
1260
1261 unsigned int
1262 Output_data_plt_i386_exec::do_fill_plt_entry(
1263 unsigned char* pov,
1264 elfcpp::Elf_types<32>::Elf_Addr got_address,
1265 unsigned int got_offset,
1266 unsigned int plt_offset,
1267 unsigned int plt_rel_offset)
1268 {
1269 memcpy(pov, plt_entry, plt_entry_size);
1270 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1271 got_address + got_offset);
1272 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1273 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1274 return 6;
1275 }
1276
1277 // Subsequent entries in the PLT for a shared object.
1278
1279 const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] =
1280 {
1281 0xff, 0xa3, // jmp *offset(%ebx)
1282 0, 0, 0, 0, // replaced with offset of symbol in .got
1283 0x68, // pushl immediate
1284 0, 0, 0, 0, // replaced with offset into relocation table
1285 0xe9, // jmp relative
1286 0, 0, 0, 0 // replaced with offset to start of .plt
1287 };
1288
1289 unsigned int
1290 Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov,
1291 elfcpp::Elf_types<32>::Elf_Addr,
1292 unsigned int got_offset,
1293 unsigned int plt_offset,
1294 unsigned int plt_rel_offset)
1295 {
1296 memcpy(pov, plt_entry, plt_entry_size);
1297 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
1298 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1299 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1300 return 6;
1301 }
1302
1303 // The .eh_frame unwind information for the PLT.
1304
1305 const unsigned char
1306 Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1307 {
1308 1, // CIE version.
1309 'z', // Augmentation: augmentation size included.
1310 'R', // Augmentation: FDE encoding included.
1311 '\0', // End of augmentation string.
1312 1, // Code alignment factor.
1313 0x7c, // Data alignment factor.
1314 8, // Return address column.
1315 1, // Augmentation size.
1316 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1317 | elfcpp::DW_EH_PE_sdata4),
1318 elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
1319 elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
1320 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1321 elfcpp::DW_CFA_nop
1322 };
1323
1324 const unsigned char
1325 Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1326 {
1327 0, 0, 0, 0, // Replaced with offset to .plt.
1328 0, 0, 0, 0, // Replaced with size of .plt.
1329 0, // Augmentation size.
1330 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
1331 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1332 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
1333 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1334 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1335 11, // Block length.
1336 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
1337 elfcpp::DW_OP_breg8, 0, // Push %eip.
1338 elfcpp::DW_OP_lit15, // Push 0xf.
1339 elfcpp::DW_OP_and, // & (%eip & 0xf).
1340 elfcpp::DW_OP_lit11, // Push 0xb.
1341 elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
1342 elfcpp::DW_OP_lit2, // Push 2.
1343 elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
1344 elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4
1345 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1346 elfcpp::DW_CFA_nop,
1347 elfcpp::DW_CFA_nop,
1348 elfcpp::DW_CFA_nop
1349 };
1350
1351 // Write out the PLT. This uses the hand-coded instructions above,
1352 // and adjusts them as needed. This is all specified by the i386 ELF
1353 // Processor Supplement.
1354
1355 void
1356 Output_data_plt_i386::do_write(Output_file* of)
1357 {
1358 const off_t offset = this->offset();
1359 const section_size_type oview_size =
1360 convert_to_section_size_type(this->data_size());
1361 unsigned char* const oview = of->get_output_view(offset, oview_size);
1362
1363 const off_t got_file_offset = this->got_plt_->offset();
1364 gold_assert(parameters->incremental_update()
1365 || (got_file_offset + this->got_plt_->data_size()
1366 == this->got_irelative_->offset()));
1367 const section_size_type got_size =
1368 convert_to_section_size_type(this->got_plt_->data_size()
1369 + this->got_irelative_->data_size());
1370
1371 unsigned char* const got_view = of->get_output_view(got_file_offset,
1372 got_size);
1373
1374 unsigned char* pov = oview;
1375
1376 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
1377 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
1378
1379 this->fill_first_plt_entry(pov, got_address);
1380 pov += this->get_plt_entry_size();
1381
1382 // The first three entries in the GOT are reserved, and are written
1383 // by Output_data_got_plt_i386::do_write.
1384 unsigned char* got_pov = got_view + 12;
1385
1386 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
1387
1388 unsigned int plt_offset = this->get_plt_entry_size();
1389 unsigned int plt_rel_offset = 0;
1390 unsigned int got_offset = 12;
1391 const unsigned int count = this->count_ + this->irelative_count_;
1392 for (unsigned int i = 0;
1393 i < count;
1394 ++i,
1395 pov += this->get_plt_entry_size(),
1396 got_pov += 4,
1397 plt_offset += this->get_plt_entry_size(),
1398 plt_rel_offset += rel_size,
1399 got_offset += 4)
1400 {
1401 // Set and adjust the PLT entry itself.
1402 unsigned int lazy_offset = this->fill_plt_entry(pov,
1403 got_address,
1404 got_offset,
1405 plt_offset,
1406 plt_rel_offset);
1407
1408 // Set the entry in the GOT.
1409 elfcpp::Swap<32, false>::writeval(got_pov,
1410 plt_address + plt_offset + lazy_offset);
1411 }
1412
1413 // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
1414 // the GOT to point to the actual symbol value, rather than point to
1415 // the PLT entry. That will let the dynamic linker call the right
1416 // function when resolving IRELATIVE relocations.
1417 unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
1418 for (std::vector<Global_ifunc>::const_iterator p =
1419 this->global_ifuncs_.begin();
1420 p != this->global_ifuncs_.end();
1421 ++p)
1422 {
1423 const Sized_symbol<32>* ssym =
1424 static_cast<const Sized_symbol<32>*>(p->sym);
1425 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1426 ssym->value());
1427 }
1428
1429 for (std::vector<Local_ifunc>::const_iterator p =
1430 this->local_ifuncs_.begin();
1431 p != this->local_ifuncs_.end();
1432 ++p)
1433 {
1434 const Symbol_value<32>* psymval =
1435 p->object->local_symbol(p->local_sym_index);
1436 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1437 psymval->value(p->object, 0));
1438 }
1439
1440 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1441 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1442
1443 of->write_output_view(offset, oview_size, oview);
1444 of->write_output_view(got_file_offset, got_size, got_view);
1445 }
1446
1447 // Create the PLT section.
1448
1449 void
1450 Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
1451 {
1452 if (this->plt_ == NULL)
1453 {
1454 // Create the GOT sections first.
1455 this->got_section(symtab, layout);
1456
1457 const bool dyn = parameters->options().output_is_position_independent();
1458 this->plt_ = this->make_data_plt(layout,
1459 this->got_plt_,
1460 this->got_irelative_,
1461 dyn);
1462
1463 // Add unwind information if requested.
1464 if (parameters->options().ld_generated_unwind_info())
1465 this->plt_->add_eh_frame(layout);
1466
1467 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1468 (elfcpp::SHF_ALLOC
1469 | elfcpp::SHF_EXECINSTR),
1470 this->plt_, ORDER_PLT, false);
1471
1472 // Make the sh_info field of .rel.plt point to .plt.
1473 Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
1474 rel_plt_os->set_info_section(this->plt_->output_section());
1475 }
1476 }
1477
1478 // Create a PLT entry for a global symbol.
1479
1480 void
1481 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
1482 {
1483 if (gsym->has_plt_offset())
1484 return;
1485 if (this->plt_ == NULL)
1486 this->make_plt_section(symtab, layout);
1487 this->plt_->add_entry(symtab, layout, gsym);
1488 }
1489
1490 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1491
1492 void
1493 Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1494 Sized_relobj_file<32, false>* relobj,
1495 unsigned int local_sym_index)
1496 {
1497 if (relobj->local_has_plt_offset(local_sym_index))
1498 return;
1499 if (this->plt_ == NULL)
1500 this->make_plt_section(symtab, layout);
1501 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1502 relobj,
1503 local_sym_index);
1504 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1505 }
1506
1507 // Return the number of entries in the PLT.
1508
1509 unsigned int
1510 Target_i386::plt_entry_count() const
1511 {
1512 if (this->plt_ == NULL)
1513 return 0;
1514 return this->plt_->entry_count();
1515 }
1516
1517 // Return the offset of the first non-reserved PLT entry.
1518
1519 unsigned int
1520 Target_i386::first_plt_entry_offset() const
1521 {
1522 return this->plt_->first_plt_entry_offset();
1523 }
1524
1525 // Return the size of each PLT entry.
1526
1527 unsigned int
1528 Target_i386::plt_entry_size() const
1529 {
1530 return this->plt_->get_plt_entry_size();
1531 }
1532
1533 // Get the section to use for TLS_DESC relocations.
1534
1535 Target_i386::Reloc_section*
1536 Target_i386::rel_tls_desc_section(Layout* layout) const
1537 {
1538 return this->plt_section()->rel_tls_desc(layout);
1539 }
1540
1541 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1542
1543 void
1544 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1545 {
1546 if (this->tls_base_symbol_defined_)
1547 return;
1548
1549 Output_segment* tls_segment = layout->tls_segment();
1550 if (tls_segment != NULL)
1551 {
1552 bool is_exec = parameters->options().output_is_executable();
1553 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1554 Symbol_table::PREDEFINED,
1555 tls_segment, 0, 0,
1556 elfcpp::STT_TLS,
1557 elfcpp::STB_LOCAL,
1558 elfcpp::STV_HIDDEN, 0,
1559 (is_exec
1560 ? Symbol::SEGMENT_END
1561 : Symbol::SEGMENT_START),
1562 true);
1563 }
1564 this->tls_base_symbol_defined_ = true;
1565 }
1566
1567 // Create a GOT entry for the TLS module index.
1568
1569 unsigned int
1570 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1571 Sized_relobj_file<32, false>* object)
1572 {
1573 if (this->got_mod_index_offset_ == -1U)
1574 {
1575 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1576 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1577 Output_data_got<32, false>* got = this->got_section(symtab, layout);
1578 unsigned int got_offset = got->add_constant(0);
1579 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
1580 got_offset);
1581 got->add_constant(0);
1582 this->got_mod_index_offset_ = got_offset;
1583 }
1584 return this->got_mod_index_offset_;
1585 }
1586
1587 // Optimize the TLS relocation type based on what we know about the
1588 // symbol. IS_FINAL is true if the final address of this symbol is
1589 // known at link time.
1590
1591 tls::Tls_optimization
1592 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
1593 {
1594 // If we are generating a shared library, then we can't do anything
1595 // in the linker.
1596 if (parameters->options().shared())
1597 return tls::TLSOPT_NONE;
1598
1599 switch (r_type)
1600 {
1601 case elfcpp::R_386_TLS_GD:
1602 case elfcpp::R_386_TLS_GOTDESC:
1603 case elfcpp::R_386_TLS_DESC_CALL:
1604 // These are General-Dynamic which permits fully general TLS
1605 // access. Since we know that we are generating an executable,
1606 // we can convert this to Initial-Exec. If we also know that
1607 // this is a local symbol, we can further switch to Local-Exec.
1608 if (is_final)
1609 return tls::TLSOPT_TO_LE;
1610 return tls::TLSOPT_TO_IE;
1611
1612 case elfcpp::R_386_TLS_LDM:
1613 // This is Local-Dynamic, which refers to a local symbol in the
1614 // dynamic TLS block. Since we know that we generating an
1615 // executable, we can switch to Local-Exec.
1616 return tls::TLSOPT_TO_LE;
1617
1618 case elfcpp::R_386_TLS_LDO_32:
1619 // Another type of Local-Dynamic relocation.
1620 return tls::TLSOPT_TO_LE;
1621
1622 case elfcpp::R_386_TLS_IE:
1623 case elfcpp::R_386_TLS_GOTIE:
1624 case elfcpp::R_386_TLS_IE_32:
1625 // These are Initial-Exec relocs which get the thread offset
1626 // from the GOT. If we know that we are linking against the
1627 // local symbol, we can switch to Local-Exec, which links the
1628 // thread offset into the instruction.
1629 if (is_final)
1630 return tls::TLSOPT_TO_LE;
1631 return tls::TLSOPT_NONE;
1632
1633 case elfcpp::R_386_TLS_LE:
1634 case elfcpp::R_386_TLS_LE_32:
1635 // When we already have Local-Exec, there is nothing further we
1636 // can do.
1637 return tls::TLSOPT_NONE;
1638
1639 default:
1640 gold_unreachable();
1641 }
1642 }
1643
1644 // Get the Reference_flags for a particular relocation.
1645
1646 int
1647 Target_i386::Scan::get_reference_flags(unsigned int r_type)
1648 {
1649 switch (r_type)
1650 {
1651 case elfcpp::R_386_NONE:
1652 case elfcpp::R_386_GNU_VTINHERIT:
1653 case elfcpp::R_386_GNU_VTENTRY:
1654 case elfcpp::R_386_GOTPC:
1655 // No symbol reference.
1656 return 0;
1657
1658 case elfcpp::R_386_32:
1659 case elfcpp::R_386_16:
1660 case elfcpp::R_386_8:
1661 return Symbol::ABSOLUTE_REF;
1662
1663 case elfcpp::R_386_PC32:
1664 case elfcpp::R_386_PC16:
1665 case elfcpp::R_386_PC8:
1666 case elfcpp::R_386_GOTOFF:
1667 return Symbol::RELATIVE_REF;
1668
1669 case elfcpp::R_386_PLT32:
1670 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1671
1672 case elfcpp::R_386_GOT32:
1673 // Absolute in GOT.
1674 return Symbol::ABSOLUTE_REF;
1675
1676 case elfcpp::R_386_TLS_GD: // Global-dynamic
1677 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1678 case elfcpp::R_386_TLS_DESC_CALL:
1679 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1680 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1681 case elfcpp::R_386_TLS_IE: // Initial-exec
1682 case elfcpp::R_386_TLS_IE_32:
1683 case elfcpp::R_386_TLS_GOTIE:
1684 case elfcpp::R_386_TLS_LE: // Local-exec
1685 case elfcpp::R_386_TLS_LE_32:
1686 return Symbol::TLS_REF;
1687
1688 case elfcpp::R_386_COPY:
1689 case elfcpp::R_386_GLOB_DAT:
1690 case elfcpp::R_386_JUMP_SLOT:
1691 case elfcpp::R_386_RELATIVE:
1692 case elfcpp::R_386_IRELATIVE:
1693 case elfcpp::R_386_TLS_TPOFF:
1694 case elfcpp::R_386_TLS_DTPMOD32:
1695 case elfcpp::R_386_TLS_DTPOFF32:
1696 case elfcpp::R_386_TLS_TPOFF32:
1697 case elfcpp::R_386_TLS_DESC:
1698 case elfcpp::R_386_32PLT:
1699 case elfcpp::R_386_TLS_GD_32:
1700 case elfcpp::R_386_TLS_GD_PUSH:
1701 case elfcpp::R_386_TLS_GD_CALL:
1702 case elfcpp::R_386_TLS_GD_POP:
1703 case elfcpp::R_386_TLS_LDM_32:
1704 case elfcpp::R_386_TLS_LDM_PUSH:
1705 case elfcpp::R_386_TLS_LDM_CALL:
1706 case elfcpp::R_386_TLS_LDM_POP:
1707 case elfcpp::R_386_USED_BY_INTEL_200:
1708 default:
1709 // Not expected. We will give an error later.
1710 return 0;
1711 }
1712 }
1713
1714 // Report an unsupported relocation against a local symbol.
1715
1716 void
1717 Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
1718 unsigned int r_type)
1719 {
1720 gold_error(_("%s: unsupported reloc %u against local symbol"),
1721 object->name().c_str(), r_type);
1722 }
1723
1724 // Return whether we need to make a PLT entry for a relocation of a
1725 // given type against a STT_GNU_IFUNC symbol.
1726
1727 bool
1728 Target_i386::Scan::reloc_needs_plt_for_ifunc(
1729 Sized_relobj_file<32, false>* object,
1730 unsigned int r_type)
1731 {
1732 int flags = Scan::get_reference_flags(r_type);
1733 if (flags & Symbol::TLS_REF)
1734 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1735 object->name().c_str(), r_type);
1736 return flags != 0;
1737 }
1738
1739 // Scan a relocation for a local symbol.
1740
1741 inline void
1742 Target_i386::Scan::local(Symbol_table* symtab,
1743 Layout* layout,
1744 Target_i386* target,
1745 Sized_relobj_file<32, false>* object,
1746 unsigned int data_shndx,
1747 Output_section* output_section,
1748 const elfcpp::Rel<32, false>& reloc,
1749 unsigned int r_type,
1750 const elfcpp::Sym<32, false>& lsym,
1751 bool is_discarded)
1752 {
1753 if (is_discarded)
1754 return;
1755
1756 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1757 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1758 && this->reloc_needs_plt_for_ifunc(object, r_type))
1759 {
1760 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1761 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1762 }
1763
1764 switch (r_type)
1765 {
1766 case elfcpp::R_386_NONE:
1767 case elfcpp::R_386_GNU_VTINHERIT:
1768 case elfcpp::R_386_GNU_VTENTRY:
1769 break;
1770
1771 case elfcpp::R_386_32:
1772 // If building a shared library (or a position-independent
1773 // executable), we need to create a dynamic relocation for
1774 // this location. The relocation applied at link time will
1775 // apply the link-time value, so we flag the location with
1776 // an R_386_RELATIVE relocation so the dynamic loader can
1777 // relocate it easily.
1778 if (parameters->options().output_is_position_independent())
1779 {
1780 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1781 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1782 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1783 output_section, data_shndx,
1784 reloc.get_r_offset());
1785 }
1786 break;
1787
1788 case elfcpp::R_386_16:
1789 case elfcpp::R_386_8:
1790 // If building a shared library (or a position-independent
1791 // executable), we need to create a dynamic relocation for
1792 // this location. Because the addend needs to remain in the
1793 // data section, we need to be careful not to apply this
1794 // relocation statically.
1795 if (parameters->options().output_is_position_independent())
1796 {
1797 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1798 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1799 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1800 rel_dyn->add_local(object, r_sym, r_type, output_section,
1801 data_shndx, reloc.get_r_offset());
1802 else
1803 {
1804 gold_assert(lsym.get_st_value() == 0);
1805 unsigned int shndx = lsym.get_st_shndx();
1806 bool is_ordinary;
1807 shndx = object->adjust_sym_shndx(r_sym, shndx,
1808 &is_ordinary);
1809 if (!is_ordinary)
1810 object->error(_("section symbol %u has bad shndx %u"),
1811 r_sym, shndx);
1812 else
1813 rel_dyn->add_local_section(object, shndx,
1814 r_type, output_section,
1815 data_shndx, reloc.get_r_offset());
1816 }
1817 }
1818 break;
1819
1820 case elfcpp::R_386_PC32:
1821 case elfcpp::R_386_PC16:
1822 case elfcpp::R_386_PC8:
1823 break;
1824
1825 case elfcpp::R_386_PLT32:
1826 // Since we know this is a local symbol, we can handle this as a
1827 // PC32 reloc.
1828 break;
1829
1830 case elfcpp::R_386_GOTOFF:
1831 case elfcpp::R_386_GOTPC:
1832 // We need a GOT section.
1833 target->got_section(symtab, layout);
1834 break;
1835
1836 case elfcpp::R_386_GOT32:
1837 {
1838 // The symbol requires a GOT entry.
1839 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1840 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1841
1842 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1843 // lets function pointers compare correctly with shared
1844 // libraries. Otherwise we would need an IRELATIVE reloc.
1845 bool is_new;
1846 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1847 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1848 else
1849 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1850 if (is_new)
1851 {
1852 // If we are generating a shared object, we need to add a
1853 // dynamic RELATIVE relocation for this symbol's GOT entry.
1854 if (parameters->options().output_is_position_independent())
1855 {
1856 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1857 unsigned int got_offset =
1858 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1859 rel_dyn->add_local_relative(object, r_sym,
1860 elfcpp::R_386_RELATIVE,
1861 got, got_offset);
1862 }
1863 }
1864 }
1865 break;
1866
1867 // These are relocations which should only be seen by the
1868 // dynamic linker, and should never be seen here.
1869 case elfcpp::R_386_COPY:
1870 case elfcpp::R_386_GLOB_DAT:
1871 case elfcpp::R_386_JUMP_SLOT:
1872 case elfcpp::R_386_RELATIVE:
1873 case elfcpp::R_386_IRELATIVE:
1874 case elfcpp::R_386_TLS_TPOFF:
1875 case elfcpp::R_386_TLS_DTPMOD32:
1876 case elfcpp::R_386_TLS_DTPOFF32:
1877 case elfcpp::R_386_TLS_TPOFF32:
1878 case elfcpp::R_386_TLS_DESC:
1879 gold_error(_("%s: unexpected reloc %u in object file"),
1880 object->name().c_str(), r_type);
1881 break;
1882
1883 // These are initial TLS relocs, which are expected when
1884 // linking.
1885 case elfcpp::R_386_TLS_GD: // Global-dynamic
1886 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1887 case elfcpp::R_386_TLS_DESC_CALL:
1888 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1889 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1890 case elfcpp::R_386_TLS_IE: // Initial-exec
1891 case elfcpp::R_386_TLS_IE_32:
1892 case elfcpp::R_386_TLS_GOTIE:
1893 case elfcpp::R_386_TLS_LE: // Local-exec
1894 case elfcpp::R_386_TLS_LE_32:
1895 {
1896 bool output_is_shared = parameters->options().shared();
1897 const tls::Tls_optimization optimized_type
1898 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1899 switch (r_type)
1900 {
1901 case elfcpp::R_386_TLS_GD: // Global-dynamic
1902 if (optimized_type == tls::TLSOPT_NONE)
1903 {
1904 // Create a pair of GOT entries for the module index and
1905 // dtv-relative offset.
1906 Output_data_got<32, false>* got
1907 = target->got_section(symtab, layout);
1908 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1909 unsigned int shndx = lsym.get_st_shndx();
1910 bool is_ordinary;
1911 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1912 if (!is_ordinary)
1913 object->error(_("local symbol %u has bad shndx %u"),
1914 r_sym, shndx);
1915 else
1916 got->add_local_pair_with_rel(object, r_sym, shndx,
1917 GOT_TYPE_TLS_PAIR,
1918 target->rel_dyn_section(layout),
1919 elfcpp::R_386_TLS_DTPMOD32);
1920 }
1921 else if (optimized_type != tls::TLSOPT_TO_LE)
1922 unsupported_reloc_local(object, r_type);
1923 break;
1924
1925 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1926 target->define_tls_base_symbol(symtab, layout);
1927 if (optimized_type == tls::TLSOPT_NONE)
1928 {
1929 // Create a double GOT entry with an R_386_TLS_DESC
1930 // reloc. The R_386_TLS_DESC reloc is resolved
1931 // lazily, so the GOT entry needs to be in an area in
1932 // .got.plt, not .got. Call got_section to make sure
1933 // the section has been created.
1934 target->got_section(symtab, layout);
1935 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1936 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1937 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1938 {
1939 unsigned int got_offset = got->add_constant(0);
1940 // The local symbol value is stored in the second
1941 // GOT entry.
1942 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1943 // That set the GOT offset of the local symbol to
1944 // point to the second entry, but we want it to
1945 // point to the first.
1946 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1947 got_offset);
1948 Reloc_section* rt = target->rel_tls_desc_section(layout);
1949 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1950 }
1951 }
1952 else if (optimized_type != tls::TLSOPT_TO_LE)
1953 unsupported_reloc_local(object, r_type);
1954 break;
1955
1956 case elfcpp::R_386_TLS_DESC_CALL:
1957 break;
1958
1959 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1960 if (optimized_type == tls::TLSOPT_NONE)
1961 {
1962 // Create a GOT entry for the module index.
1963 target->got_mod_index_entry(symtab, layout, object);
1964 }
1965 else if (optimized_type != tls::TLSOPT_TO_LE)
1966 unsupported_reloc_local(object, r_type);
1967 break;
1968
1969 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1970 break;
1971
1972 case elfcpp::R_386_TLS_IE: // Initial-exec
1973 case elfcpp::R_386_TLS_IE_32:
1974 case elfcpp::R_386_TLS_GOTIE:
1975 layout->set_has_static_tls();
1976 if (optimized_type == tls::TLSOPT_NONE)
1977 {
1978 // For the R_386_TLS_IE relocation, we need to create a
1979 // dynamic relocation when building a shared library.
1980 if (r_type == elfcpp::R_386_TLS_IE
1981 && parameters->options().shared())
1982 {
1983 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1984 unsigned int r_sym
1985 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1986 rel_dyn->add_local_relative(object, r_sym,
1987 elfcpp::R_386_RELATIVE,
1988 output_section, data_shndx,
1989 reloc.get_r_offset());
1990 }
1991 // Create a GOT entry for the tp-relative offset.
1992 Output_data_got<32, false>* got
1993 = target->got_section(symtab, layout);
1994 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1995 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1996 ? elfcpp::R_386_TLS_TPOFF32
1997 : elfcpp::R_386_TLS_TPOFF);
1998 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1999 ? GOT_TYPE_TLS_OFFSET
2000 : GOT_TYPE_TLS_NOFFSET);
2001 got->add_local_with_rel(object, r_sym, got_type,
2002 target->rel_dyn_section(layout),
2003 dyn_r_type);
2004 }
2005 else if (optimized_type != tls::TLSOPT_TO_LE)
2006 unsupported_reloc_local(object, r_type);
2007 break;
2008
2009 case elfcpp::R_386_TLS_LE: // Local-exec
2010 case elfcpp::R_386_TLS_LE_32:
2011 layout->set_has_static_tls();
2012 if (output_is_shared)
2013 {
2014 // We need to create a dynamic relocation.
2015 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2016 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2017 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2018 ? elfcpp::R_386_TLS_TPOFF32
2019 : elfcpp::R_386_TLS_TPOFF);
2020 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2021 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
2022 data_shndx, reloc.get_r_offset());
2023 }
2024 break;
2025
2026 default:
2027 gold_unreachable();
2028 }
2029 }
2030 break;
2031
2032 case elfcpp::R_386_32PLT:
2033 case elfcpp::R_386_TLS_GD_32:
2034 case elfcpp::R_386_TLS_GD_PUSH:
2035 case elfcpp::R_386_TLS_GD_CALL:
2036 case elfcpp::R_386_TLS_GD_POP:
2037 case elfcpp::R_386_TLS_LDM_32:
2038 case elfcpp::R_386_TLS_LDM_PUSH:
2039 case elfcpp::R_386_TLS_LDM_CALL:
2040 case elfcpp::R_386_TLS_LDM_POP:
2041 case elfcpp::R_386_USED_BY_INTEL_200:
2042 default:
2043 unsupported_reloc_local(object, r_type);
2044 break;
2045 }
2046 }
2047
2048 // Report an unsupported relocation against a global symbol.
2049
2050 void
2051 Target_i386::Scan::unsupported_reloc_global(
2052 Sized_relobj_file<32, false>* object,
2053 unsigned int r_type,
2054 Symbol* gsym)
2055 {
2056 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2057 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2058 }
2059
2060 inline bool
2061 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
2062 {
2063 switch (r_type)
2064 {
2065 case elfcpp::R_386_32:
2066 case elfcpp::R_386_16:
2067 case elfcpp::R_386_8:
2068 case elfcpp::R_386_GOTOFF:
2069 case elfcpp::R_386_GOT32:
2070 {
2071 return true;
2072 }
2073 default:
2074 return false;
2075 }
2076 return false;
2077 }
2078
2079 inline bool
2080 Target_i386::Scan::local_reloc_may_be_function_pointer(
2081 Symbol_table* ,
2082 Layout* ,
2083 Target_i386* ,
2084 Sized_relobj_file<32, false>* ,
2085 unsigned int ,
2086 Output_section* ,
2087 const elfcpp::Rel<32, false>& ,
2088 unsigned int r_type,
2089 const elfcpp::Sym<32, false>&)
2090 {
2091 return possible_function_pointer_reloc(r_type);
2092 }
2093
2094 inline bool
2095 Target_i386::Scan::global_reloc_may_be_function_pointer(
2096 Symbol_table* ,
2097 Layout* ,
2098 Target_i386* ,
2099 Sized_relobj_file<32, false>* ,
2100 unsigned int ,
2101 Output_section* ,
2102 const elfcpp::Rel<32, false>& ,
2103 unsigned int r_type,
2104 Symbol*)
2105 {
2106 return possible_function_pointer_reloc(r_type);
2107 }
2108
2109 // Scan a relocation for a global symbol.
2110
2111 inline void
2112 Target_i386::Scan::global(Symbol_table* symtab,
2113 Layout* layout,
2114 Target_i386* target,
2115 Sized_relobj_file<32, false>* object,
2116 unsigned int data_shndx,
2117 Output_section* output_section,
2118 const elfcpp::Rel<32, false>& reloc,
2119 unsigned int r_type,
2120 Symbol* gsym)
2121 {
2122 // A STT_GNU_IFUNC symbol may require a PLT entry.
2123 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2124 && this->reloc_needs_plt_for_ifunc(object, r_type))
2125 target->make_plt_entry(symtab, layout, gsym);
2126
2127 switch (r_type)
2128 {
2129 case elfcpp::R_386_NONE:
2130 case elfcpp::R_386_GNU_VTINHERIT:
2131 case elfcpp::R_386_GNU_VTENTRY:
2132 break;
2133
2134 case elfcpp::R_386_32:
2135 case elfcpp::R_386_16:
2136 case elfcpp::R_386_8:
2137 {
2138 // Make a PLT entry if necessary.
2139 if (gsym->needs_plt_entry())
2140 {
2141 target->make_plt_entry(symtab, layout, gsym);
2142 // Since this is not a PC-relative relocation, we may be
2143 // taking the address of a function. In that case we need to
2144 // set the entry in the dynamic symbol table to the address of
2145 // the PLT entry.
2146 if (gsym->is_from_dynobj() && !parameters->options().shared())
2147 gsym->set_needs_dynsym_value();
2148 }
2149 // Make a dynamic relocation if necessary.
2150 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2151 {
2152 if (!parameters->options().output_is_position_independent()
2153 && gsym->may_need_copy_reloc())
2154 {
2155 target->copy_reloc(symtab, layout, object,
2156 data_shndx, output_section, gsym, reloc);
2157 }
2158 else if (r_type == elfcpp::R_386_32
2159 && gsym->type() == elfcpp::STT_GNU_IFUNC
2160 && gsym->can_use_relative_reloc(false)
2161 && !gsym->is_from_dynobj()
2162 && !gsym->is_undefined()
2163 && !gsym->is_preemptible())
2164 {
2165 // Use an IRELATIVE reloc for a locally defined
2166 // STT_GNU_IFUNC symbol. This makes a function
2167 // address in a PIE executable match the address in a
2168 // shared library that it links against.
2169 Reloc_section* rel_dyn = target->rel_irelative_section(layout);
2170 rel_dyn->add_symbolless_global_addend(gsym,
2171 elfcpp::R_386_IRELATIVE,
2172 output_section,
2173 object, data_shndx,
2174 reloc.get_r_offset());
2175 }
2176 else if (r_type == elfcpp::R_386_32
2177 && gsym->can_use_relative_reloc(false))
2178 {
2179 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2180 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2181 output_section, object,
2182 data_shndx, reloc.get_r_offset());
2183 }
2184 else
2185 {
2186 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2187 rel_dyn->add_global(gsym, r_type, output_section, object,
2188 data_shndx, reloc.get_r_offset());
2189 }
2190 }
2191 }
2192 break;
2193
2194 case elfcpp::R_386_PC32:
2195 case elfcpp::R_386_PC16:
2196 case elfcpp::R_386_PC8:
2197 {
2198 // Make a PLT entry if necessary.
2199 if (gsym->needs_plt_entry())
2200 {
2201 // These relocations are used for function calls only in
2202 // non-PIC code. For a 32-bit relocation in a shared library,
2203 // we'll need a text relocation anyway, so we can skip the
2204 // PLT entry and let the dynamic linker bind the call directly
2205 // to the target. For smaller relocations, we should use a
2206 // PLT entry to ensure that the call can reach.
2207 if (!parameters->options().shared()
2208 || r_type != elfcpp::R_386_PC32)
2209 target->make_plt_entry(symtab, layout, gsym);
2210 }
2211 // Make a dynamic relocation if necessary.
2212 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2213 {
2214 if (parameters->options().output_is_executable()
2215 && gsym->may_need_copy_reloc())
2216 {
2217 target->copy_reloc(symtab, layout, object,
2218 data_shndx, output_section, gsym, reloc);
2219 }
2220 else
2221 {
2222 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2223 rel_dyn->add_global(gsym, r_type, output_section, object,
2224 data_shndx, reloc.get_r_offset());
2225 }
2226 }
2227 }
2228 break;
2229
2230 case elfcpp::R_386_GOT32:
2231 {
2232 // The symbol requires a GOT entry.
2233 Output_data_got<32, false>* got = target->got_section(symtab, layout);
2234 if (gsym->final_value_is_known())
2235 {
2236 // For a STT_GNU_IFUNC symbol we want the PLT address.
2237 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2238 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2239 else
2240 got->add_global(gsym, GOT_TYPE_STANDARD);
2241 }
2242 else
2243 {
2244 // If this symbol is not fully resolved, we need to add a
2245 // GOT entry with a dynamic relocation.
2246 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2247
2248 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2249 //
2250 // 1) The symbol may be defined in some other module.
2251 //
2252 // 2) We are building a shared library and this is a
2253 // protected symbol; using GLOB_DAT means that the dynamic
2254 // linker can use the address of the PLT in the main
2255 // executable when appropriate so that function address
2256 // comparisons work.
2257 //
2258 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2259 // code, again so that function address comparisons work.
2260 if (gsym->is_from_dynobj()
2261 || gsym->is_undefined()
2262 || gsym->is_preemptible()
2263 || (gsym->visibility() == elfcpp::STV_PROTECTED
2264 && parameters->options().shared())
2265 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2266 && parameters->options().output_is_position_independent()))
2267 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
2268 rel_dyn, elfcpp::R_386_GLOB_DAT);
2269 else
2270 {
2271 // For a STT_GNU_IFUNC symbol we want to write the PLT
2272 // offset into the GOT, so that function pointer
2273 // comparisons work correctly.
2274 bool is_new;
2275 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2276 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2277 else
2278 {
2279 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2280 // Tell the dynamic linker to use the PLT address
2281 // when resolving relocations.
2282 if (gsym->is_from_dynobj()
2283 && !parameters->options().shared())
2284 gsym->set_needs_dynsym_value();
2285 }
2286 if (is_new)
2287 {
2288 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2289 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2290 got, got_off);
2291 }
2292 }
2293 }
2294 }
2295 break;
2296
2297 case elfcpp::R_386_PLT32:
2298 // If the symbol is fully resolved, this is just a PC32 reloc.
2299 // Otherwise we need a PLT entry.
2300 if (gsym->final_value_is_known())
2301 break;
2302 // If building a shared library, we can also skip the PLT entry
2303 // if the symbol is defined in the output file and is protected
2304 // or hidden.
2305 if (gsym->is_defined()
2306 && !gsym->is_from_dynobj()
2307 && !gsym->is_preemptible())
2308 break;
2309 target->make_plt_entry(symtab, layout, gsym);
2310 break;
2311
2312 case elfcpp::R_386_GOTOFF:
2313 case elfcpp::R_386_GOTPC:
2314 // We need a GOT section.
2315 target->got_section(symtab, layout);
2316 break;
2317
2318 // These are relocations which should only be seen by the
2319 // dynamic linker, and should never be seen here.
2320 case elfcpp::R_386_COPY:
2321 case elfcpp::R_386_GLOB_DAT:
2322 case elfcpp::R_386_JUMP_SLOT:
2323 case elfcpp::R_386_RELATIVE:
2324 case elfcpp::R_386_IRELATIVE:
2325 case elfcpp::R_386_TLS_TPOFF:
2326 case elfcpp::R_386_TLS_DTPMOD32:
2327 case elfcpp::R_386_TLS_DTPOFF32:
2328 case elfcpp::R_386_TLS_TPOFF32:
2329 case elfcpp::R_386_TLS_DESC:
2330 gold_error(_("%s: unexpected reloc %u in object file"),
2331 object->name().c_str(), r_type);
2332 break;
2333
2334 // These are initial tls relocs, which are expected when
2335 // linking.
2336 case elfcpp::R_386_TLS_GD: // Global-dynamic
2337 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2338 case elfcpp::R_386_TLS_DESC_CALL:
2339 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2340 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2341 case elfcpp::R_386_TLS_IE: // Initial-exec
2342 case elfcpp::R_386_TLS_IE_32:
2343 case elfcpp::R_386_TLS_GOTIE:
2344 case elfcpp::R_386_TLS_LE: // Local-exec
2345 case elfcpp::R_386_TLS_LE_32:
2346 {
2347 const bool is_final = gsym->final_value_is_known();
2348 const tls::Tls_optimization optimized_type
2349 = Target_i386::optimize_tls_reloc(is_final, r_type);
2350 switch (r_type)
2351 {
2352 case elfcpp::R_386_TLS_GD: // Global-dynamic
2353 if (optimized_type == tls::TLSOPT_NONE)
2354 {
2355 // Create a pair of GOT entries for the module index and
2356 // dtv-relative offset.
2357 Output_data_got<32, false>* got
2358 = target->got_section(symtab, layout);
2359 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2360 target->rel_dyn_section(layout),
2361 elfcpp::R_386_TLS_DTPMOD32,
2362 elfcpp::R_386_TLS_DTPOFF32);
2363 }
2364 else if (optimized_type == tls::TLSOPT_TO_IE)
2365 {
2366 // Create a GOT entry for the tp-relative offset.
2367 Output_data_got<32, false>* got
2368 = target->got_section(symtab, layout);
2369 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2370 target->rel_dyn_section(layout),
2371 elfcpp::R_386_TLS_TPOFF);
2372 }
2373 else if (optimized_type != tls::TLSOPT_TO_LE)
2374 unsupported_reloc_global(object, r_type, gsym);
2375 break;
2376
2377 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
2378 target->define_tls_base_symbol(symtab, layout);
2379 if (optimized_type == tls::TLSOPT_NONE)
2380 {
2381 // Create a double GOT entry with an R_386_TLS_DESC
2382 // reloc. The R_386_TLS_DESC reloc is resolved
2383 // lazily, so the GOT entry needs to be in an area in
2384 // .got.plt, not .got. Call got_section to make sure
2385 // the section has been created.
2386 target->got_section(symtab, layout);
2387 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2388 Reloc_section* rt = target->rel_tls_desc_section(layout);
2389 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2390 elfcpp::R_386_TLS_DESC, 0);
2391 }
2392 else if (optimized_type == tls::TLSOPT_TO_IE)
2393 {
2394 // Create a GOT entry for the tp-relative offset.
2395 Output_data_got<32, false>* got
2396 = target->got_section(symtab, layout);
2397 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2398 target->rel_dyn_section(layout),
2399 elfcpp::R_386_TLS_TPOFF);
2400 }
2401 else if (optimized_type != tls::TLSOPT_TO_LE)
2402 unsupported_reloc_global(object, r_type, gsym);
2403 break;
2404
2405 case elfcpp::R_386_TLS_DESC_CALL:
2406 break;
2407
2408 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2409 if (optimized_type == tls::TLSOPT_NONE)
2410 {
2411 // Create a GOT entry for the module index.
2412 target->got_mod_index_entry(symtab, layout, object);
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_LDO_32: // Alternate local-dynamic
2419 break;
2420
2421 case elfcpp::R_386_TLS_IE: // Initial-exec
2422 case elfcpp::R_386_TLS_IE_32:
2423 case elfcpp::R_386_TLS_GOTIE:
2424 layout->set_has_static_tls();
2425 if (optimized_type == tls::TLSOPT_NONE)
2426 {
2427 // For the R_386_TLS_IE relocation, we need to create a
2428 // dynamic relocation when building a shared library.
2429 if (r_type == elfcpp::R_386_TLS_IE
2430 && parameters->options().shared())
2431 {
2432 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2433 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2434 output_section, object,
2435 data_shndx,
2436 reloc.get_r_offset());
2437 }
2438 // Create a GOT entry for the tp-relative offset.
2439 Output_data_got<32, false>* got
2440 = target->got_section(symtab, layout);
2441 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2442 ? elfcpp::R_386_TLS_TPOFF32
2443 : elfcpp::R_386_TLS_TPOFF);
2444 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2445 ? GOT_TYPE_TLS_OFFSET
2446 : GOT_TYPE_TLS_NOFFSET);
2447 got->add_global_with_rel(gsym, got_type,
2448 target->rel_dyn_section(layout),
2449 dyn_r_type);
2450 }
2451 else if (optimized_type != tls::TLSOPT_TO_LE)
2452 unsupported_reloc_global(object, r_type, gsym);
2453 break;
2454
2455 case elfcpp::R_386_TLS_LE: // Local-exec
2456 case elfcpp::R_386_TLS_LE_32:
2457 layout->set_has_static_tls();
2458 if (parameters->options().shared())
2459 {
2460 // We need to create a dynamic relocation.
2461 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2462 ? elfcpp::R_386_TLS_TPOFF32
2463 : elfcpp::R_386_TLS_TPOFF);
2464 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2465 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
2466 data_shndx, reloc.get_r_offset());
2467 }
2468 break;
2469
2470 default:
2471 gold_unreachable();
2472 }
2473 }
2474 break;
2475
2476 case elfcpp::R_386_32PLT:
2477 case elfcpp::R_386_TLS_GD_32:
2478 case elfcpp::R_386_TLS_GD_PUSH:
2479 case elfcpp::R_386_TLS_GD_CALL:
2480 case elfcpp::R_386_TLS_GD_POP:
2481 case elfcpp::R_386_TLS_LDM_32:
2482 case elfcpp::R_386_TLS_LDM_PUSH:
2483 case elfcpp::R_386_TLS_LDM_CALL:
2484 case elfcpp::R_386_TLS_LDM_POP:
2485 case elfcpp::R_386_USED_BY_INTEL_200:
2486 default:
2487 unsupported_reloc_global(object, r_type, gsym);
2488 break;
2489 }
2490 }
2491
2492 // Process relocations for gc.
2493
2494 void
2495 Target_i386::gc_process_relocs(Symbol_table* symtab,
2496 Layout* layout,
2497 Sized_relobj_file<32, false>* object,
2498 unsigned int data_shndx,
2499 unsigned int,
2500 const unsigned char* prelocs,
2501 size_t reloc_count,
2502 Output_section* output_section,
2503 bool needs_special_offset_handling,
2504 size_t local_symbol_count,
2505 const unsigned char* plocal_symbols)
2506 {
2507 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2508 Target_i386::Scan,
2509 Target_i386::Relocatable_size_for_reloc>(
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 // Scan relocations for a section.
2524
2525 void
2526 Target_i386::scan_relocs(Symbol_table* symtab,
2527 Layout* layout,
2528 Sized_relobj_file<32, false>* object,
2529 unsigned int data_shndx,
2530 unsigned int sh_type,
2531 const unsigned char* prelocs,
2532 size_t reloc_count,
2533 Output_section* output_section,
2534 bool needs_special_offset_handling,
2535 size_t local_symbol_count,
2536 const unsigned char* plocal_symbols)
2537 {
2538 if (sh_type == elfcpp::SHT_RELA)
2539 {
2540 gold_error(_("%s: unsupported RELA reloc section"),
2541 object->name().c_str());
2542 return;
2543 }
2544
2545 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2546 Target_i386::Scan>(
2547 symtab,
2548 layout,
2549 this,
2550 object,
2551 data_shndx,
2552 prelocs,
2553 reloc_count,
2554 output_section,
2555 needs_special_offset_handling,
2556 local_symbol_count,
2557 plocal_symbols);
2558 }
2559
2560 // Finalize the sections.
2561
2562 void
2563 Target_i386::do_finalize_sections(
2564 Layout* layout,
2565 const Input_objects*,
2566 Symbol_table* symtab)
2567 {
2568 const Reloc_section* rel_plt = (this->plt_ == NULL
2569 ? NULL
2570 : this->plt_->rel_plt());
2571 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
2572 this->rel_dyn_, true, false);
2573
2574 // Emit any relocs we saved in an attempt to avoid generating COPY
2575 // relocs.
2576 if (this->copy_relocs_.any_saved_relocs())
2577 this->copy_relocs_.emit(this->rel_dyn_section(layout));
2578
2579 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2580 // the .got.plt section.
2581 Symbol* sym = this->global_offset_table_;
2582 if (sym != NULL)
2583 {
2584 uint32_t data_size = this->got_plt_->current_data_size();
2585 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
2586 }
2587
2588 if (parameters->doing_static_link()
2589 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2590 {
2591 // If linking statically, make sure that the __rel_iplt symbols
2592 // were defined if necessary, even if we didn't create a PLT.
2593 static const Define_symbol_in_segment syms[] =
2594 {
2595 {
2596 "__rel_iplt_start", // name
2597 elfcpp::PT_LOAD, // segment_type
2598 elfcpp::PF_W, // segment_flags_set
2599 elfcpp::PF(0), // segment_flags_clear
2600 0, // value
2601 0, // size
2602 elfcpp::STT_NOTYPE, // type
2603 elfcpp::STB_GLOBAL, // binding
2604 elfcpp::STV_HIDDEN, // visibility
2605 0, // nonvis
2606 Symbol::SEGMENT_START, // offset_from_base
2607 true // only_if_ref
2608 },
2609 {
2610 "__rel_iplt_end", // name
2611 elfcpp::PT_LOAD, // segment_type
2612 elfcpp::PF_W, // segment_flags_set
2613 elfcpp::PF(0), // segment_flags_clear
2614 0, // value
2615 0, // size
2616 elfcpp::STT_NOTYPE, // type
2617 elfcpp::STB_GLOBAL, // binding
2618 elfcpp::STV_HIDDEN, // visibility
2619 0, // nonvis
2620 Symbol::SEGMENT_START, // offset_from_base
2621 true // only_if_ref
2622 }
2623 };
2624
2625 symtab->define_symbols(layout, 2, syms,
2626 layout->script_options()->saw_sections_clause());
2627 }
2628 }
2629
2630 // Return whether a direct absolute static relocation needs to be applied.
2631 // In cases where Scan::local() or Scan::global() has created
2632 // a dynamic relocation other than R_386_RELATIVE, the addend
2633 // of the relocation is carried in the data, and we must not
2634 // apply the static relocation.
2635
2636 inline bool
2637 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
2638 unsigned int r_type,
2639 bool is_32bit,
2640 Output_section* output_section)
2641 {
2642 // If the output section is not allocated, then we didn't call
2643 // scan_relocs, we didn't create a dynamic reloc, and we must apply
2644 // the reloc here.
2645 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
2646 return true;
2647
2648 int ref_flags = Scan::get_reference_flags(r_type);
2649
2650 // For local symbols, we will have created a non-RELATIVE dynamic
2651 // relocation only if (a) the output is position independent,
2652 // (b) the relocation is absolute (not pc- or segment-relative), and
2653 // (c) the relocation is not 32 bits wide.
2654 if (gsym == NULL)
2655 return !(parameters->options().output_is_position_independent()
2656 && (ref_flags & Symbol::ABSOLUTE_REF)
2657 && !is_32bit);
2658
2659 // For global symbols, we use the same helper routines used in the
2660 // scan pass. If we did not create a dynamic relocation, or if we
2661 // created a RELATIVE dynamic relocation, we should apply the static
2662 // relocation.
2663 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
2664 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
2665 && gsym->can_use_relative_reloc(ref_flags
2666 & Symbol::FUNCTION_CALL);
2667 return !has_dyn || is_rel;
2668 }
2669
2670 // Perform a relocation.
2671
2672 inline bool
2673 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
2674 Target_i386* target,
2675 Output_section* output_section,
2676 size_t relnum,
2677 const elfcpp::Rel<32, false>& rel,
2678 unsigned int r_type,
2679 const Sized_symbol<32>* gsym,
2680 const Symbol_value<32>* psymval,
2681 unsigned char* view,
2682 elfcpp::Elf_types<32>::Elf_Addr address,
2683 section_size_type view_size)
2684 {
2685 if (this->skip_call_tls_get_addr_)
2686 {
2687 if ((r_type != elfcpp::R_386_PLT32
2688 && r_type != elfcpp::R_386_PC32)
2689 || gsym == NULL
2690 || strcmp(gsym->name(), "___tls_get_addr") != 0)
2691 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2692 _("missing expected TLS relocation"));
2693 else
2694 {
2695 this->skip_call_tls_get_addr_ = false;
2696 return false;
2697 }
2698 }
2699
2700 if (view == NULL)
2701 return true;
2702
2703 const Sized_relobj_file<32, false>* object = relinfo->object;
2704
2705 // Pick the value to use for symbols defined in shared objects.
2706 Symbol_value<32> symval;
2707 if (gsym != NULL
2708 && gsym->type() == elfcpp::STT_GNU_IFUNC
2709 && r_type == elfcpp::R_386_32
2710 && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
2711 && gsym->can_use_relative_reloc(false)
2712 && !gsym->is_from_dynobj()
2713 && !gsym->is_undefined()
2714 && !gsym->is_preemptible())
2715 {
2716 // In this case we are generating a R_386_IRELATIVE reloc. We
2717 // want to use the real value of the symbol, not the PLT offset.
2718 }
2719 else if (gsym != NULL
2720 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2721 {
2722 symval.set_output_value(target->plt_address_for_global(gsym));
2723 psymval = &symval;
2724 }
2725 else if (gsym == NULL && psymval->is_ifunc_symbol())
2726 {
2727 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2728 if (object->local_has_plt_offset(r_sym))
2729 {
2730 symval.set_output_value(target->plt_address_for_local(object, r_sym));
2731 psymval = &symval;
2732 }
2733 }
2734
2735 // Get the GOT offset if needed.
2736 // The GOT pointer points to the end of the GOT section.
2737 // We need to subtract the size of the GOT section to get
2738 // the actual offset to use in the relocation.
2739 bool have_got_offset = false;
2740 unsigned int got_offset = 0;
2741 switch (r_type)
2742 {
2743 case elfcpp::R_386_GOT32:
2744 if (gsym != NULL)
2745 {
2746 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2747 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
2748 - target->got_size());
2749 }
2750 else
2751 {
2752 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2753 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2754 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2755 - target->got_size());
2756 }
2757 have_got_offset = true;
2758 break;
2759
2760 default:
2761 break;
2762 }
2763
2764 switch (r_type)
2765 {
2766 case elfcpp::R_386_NONE:
2767 case elfcpp::R_386_GNU_VTINHERIT:
2768 case elfcpp::R_386_GNU_VTENTRY:
2769 break;
2770
2771 case elfcpp::R_386_32:
2772 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2773 Relocate_functions<32, false>::rel32(view, object, psymval);
2774 break;
2775
2776 case elfcpp::R_386_PC32:
2777 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2778 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2779 break;
2780
2781 case elfcpp::R_386_16:
2782 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2783 Relocate_functions<32, false>::rel16(view, object, psymval);
2784 break;
2785
2786 case elfcpp::R_386_PC16:
2787 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2788 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
2789 break;
2790
2791 case elfcpp::R_386_8:
2792 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2793 Relocate_functions<32, false>::rel8(view, object, psymval);
2794 break;
2795
2796 case elfcpp::R_386_PC8:
2797 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2798 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
2799 break;
2800
2801 case elfcpp::R_386_PLT32:
2802 gold_assert(gsym == NULL
2803 || gsym->has_plt_offset()
2804 || gsym->final_value_is_known()
2805 || (gsym->is_defined()
2806 && !gsym->is_from_dynobj()
2807 && !gsym->is_preemptible()));
2808 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2809 break;
2810
2811 case elfcpp::R_386_GOT32:
2812 gold_assert(have_got_offset);
2813 Relocate_functions<32, false>::rel32(view, got_offset);
2814 break;
2815
2816 case elfcpp::R_386_GOTOFF:
2817 {
2818 elfcpp::Elf_types<32>::Elf_Addr value;
2819 value = (psymval->value(object, 0)
2820 - target->got_plt_section()->address());
2821 Relocate_functions<32, false>::rel32(view, value);
2822 }
2823 break;
2824
2825 case elfcpp::R_386_GOTPC:
2826 {
2827 elfcpp::Elf_types<32>::Elf_Addr value;
2828 value = target->got_plt_section()->address();
2829 Relocate_functions<32, false>::pcrel32(view, value, address);
2830 }
2831 break;
2832
2833 case elfcpp::R_386_COPY:
2834 case elfcpp::R_386_GLOB_DAT:
2835 case elfcpp::R_386_JUMP_SLOT:
2836 case elfcpp::R_386_RELATIVE:
2837 case elfcpp::R_386_IRELATIVE:
2838 // These are outstanding tls relocs, which are unexpected when
2839 // linking.
2840 case elfcpp::R_386_TLS_TPOFF:
2841 case elfcpp::R_386_TLS_DTPMOD32:
2842 case elfcpp::R_386_TLS_DTPOFF32:
2843 case elfcpp::R_386_TLS_TPOFF32:
2844 case elfcpp::R_386_TLS_DESC:
2845 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2846 _("unexpected reloc %u in object file"),
2847 r_type);
2848 break;
2849
2850 // These are initial tls relocs, which are expected when
2851 // linking.
2852 case elfcpp::R_386_TLS_GD: // Global-dynamic
2853 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2854 case elfcpp::R_386_TLS_DESC_CALL:
2855 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2856 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2857 case elfcpp::R_386_TLS_IE: // Initial-exec
2858 case elfcpp::R_386_TLS_IE_32:
2859 case elfcpp::R_386_TLS_GOTIE:
2860 case elfcpp::R_386_TLS_LE: // Local-exec
2861 case elfcpp::R_386_TLS_LE_32:
2862 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
2863 view, address, view_size);
2864 break;
2865
2866 case elfcpp::R_386_32PLT:
2867 case elfcpp::R_386_TLS_GD_32:
2868 case elfcpp::R_386_TLS_GD_PUSH:
2869 case elfcpp::R_386_TLS_GD_CALL:
2870 case elfcpp::R_386_TLS_GD_POP:
2871 case elfcpp::R_386_TLS_LDM_32:
2872 case elfcpp::R_386_TLS_LDM_PUSH:
2873 case elfcpp::R_386_TLS_LDM_CALL:
2874 case elfcpp::R_386_TLS_LDM_POP:
2875 case elfcpp::R_386_USED_BY_INTEL_200:
2876 default:
2877 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2878 _("unsupported reloc %u"),
2879 r_type);
2880 break;
2881 }
2882
2883 return true;
2884 }
2885
2886 // Perform a TLS relocation.
2887
2888 inline void
2889 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
2890 Target_i386* target,
2891 size_t relnum,
2892 const elfcpp::Rel<32, false>& rel,
2893 unsigned int r_type,
2894 const Sized_symbol<32>* gsym,
2895 const Symbol_value<32>* psymval,
2896 unsigned char* view,
2897 elfcpp::Elf_types<32>::Elf_Addr,
2898 section_size_type view_size)
2899 {
2900 Output_segment* tls_segment = relinfo->layout->tls_segment();
2901
2902 const Sized_relobj_file<32, false>* object = relinfo->object;
2903
2904 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
2905
2906 const bool is_final = (gsym == NULL
2907 ? !parameters->options().shared()
2908 : gsym->final_value_is_known());
2909 const tls::Tls_optimization optimized_type
2910 = Target_i386::optimize_tls_reloc(is_final, r_type);
2911 switch (r_type)
2912 {
2913 case elfcpp::R_386_TLS_GD: // Global-dynamic
2914 if (optimized_type == tls::TLSOPT_TO_LE)
2915 {
2916 if (tls_segment == NULL)
2917 {
2918 gold_assert(parameters->errors()->error_count() > 0
2919 || issue_undefined_symbol_error(gsym));
2920 return;
2921 }
2922 this->tls_gd_to_le(relinfo, relnum, tls_segment,
2923 rel, r_type, value, view,
2924 view_size);
2925 break;
2926 }
2927 else
2928 {
2929 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2930 ? GOT_TYPE_TLS_NOFFSET
2931 : GOT_TYPE_TLS_PAIR);
2932 unsigned int got_offset;
2933 if (gsym != NULL)
2934 {
2935 gold_assert(gsym->has_got_offset(got_type));
2936 got_offset = gsym->got_offset(got_type) - target->got_size();
2937 }
2938 else
2939 {
2940 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2941 gold_assert(object->local_has_got_offset(r_sym, got_type));
2942 got_offset = (object->local_got_offset(r_sym, got_type)
2943 - target->got_size());
2944 }
2945 if (optimized_type == tls::TLSOPT_TO_IE)
2946 {
2947 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2948 got_offset, view, view_size);
2949 break;
2950 }
2951 else if (optimized_type == tls::TLSOPT_NONE)
2952 {
2953 // Relocate the field with the offset of the pair of GOT
2954 // entries.
2955 Relocate_functions<32, false>::rel32(view, got_offset);
2956 break;
2957 }
2958 }
2959 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2960 _("unsupported reloc %u"),
2961 r_type);
2962 break;
2963
2964 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2965 case elfcpp::R_386_TLS_DESC_CALL:
2966 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2967 if (optimized_type == tls::TLSOPT_TO_LE)
2968 {
2969 if (tls_segment == NULL)
2970 {
2971 gold_assert(parameters->errors()->error_count() > 0
2972 || issue_undefined_symbol_error(gsym));
2973 return;
2974 }
2975 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2976 rel, r_type, value, view,
2977 view_size);
2978 break;
2979 }
2980 else
2981 {
2982 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2983 ? GOT_TYPE_TLS_NOFFSET
2984 : GOT_TYPE_TLS_DESC);
2985 unsigned int got_offset = 0;
2986 if (r_type == elfcpp::R_386_TLS_GOTDESC
2987 && optimized_type == tls::TLSOPT_NONE)
2988 {
2989 // We created GOT entries in the .got.tlsdesc portion of
2990 // the .got.plt section, but the offset stored in the
2991 // symbol is the offset within .got.tlsdesc.
2992 got_offset = (target->got_size()
2993 + target->got_plt_section()->data_size());
2994 }
2995 if (gsym != NULL)
2996 {
2997 gold_assert(gsym->has_got_offset(got_type));
2998 got_offset += gsym->got_offset(got_type) - target->got_size();
2999 }
3000 else
3001 {
3002 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3003 gold_assert(object->local_has_got_offset(r_sym, got_type));
3004 got_offset += (object->local_got_offset(r_sym, got_type)
3005 - target->got_size());
3006 }
3007 if (optimized_type == tls::TLSOPT_TO_IE)
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_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
3016 got_offset, view, view_size);
3017 break;
3018 }
3019 else if (optimized_type == tls::TLSOPT_NONE)
3020 {
3021 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3022 {
3023 // Relocate the field with the offset of the pair of GOT
3024 // entries.
3025 Relocate_functions<32, false>::rel32(view, got_offset);
3026 }
3027 break;
3028 }
3029 }
3030 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3031 _("unsupported reloc %u"),
3032 r_type);
3033 break;
3034
3035 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3036 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
3037 {
3038 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3039 _("both SUN and GNU model "
3040 "TLS relocations"));
3041 break;
3042 }
3043 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3044 if (optimized_type == tls::TLSOPT_TO_LE)
3045 {
3046 if (tls_segment == NULL)
3047 {
3048 gold_assert(parameters->errors()->error_count() > 0
3049 || issue_undefined_symbol_error(gsym));
3050 return;
3051 }
3052 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
3053 value, view, view_size);
3054 break;
3055 }
3056 else if (optimized_type == tls::TLSOPT_NONE)
3057 {
3058 // Relocate the field with the offset of the GOT entry for
3059 // the module index.
3060 unsigned int got_offset;
3061 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3062 - target->got_size());
3063 Relocate_functions<32, false>::rel32(view, got_offset);
3064 break;
3065 }
3066 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3067 _("unsupported reloc %u"),
3068 r_type);
3069 break;
3070
3071 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3072 if (optimized_type == tls::TLSOPT_TO_LE)
3073 {
3074 // This reloc can appear in debugging sections, in which
3075 // case we must not convert to local-exec. We decide what
3076 // to do based on whether the section is marked as
3077 // containing executable code. That is what the GNU linker
3078 // does as well.
3079 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
3080 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
3081 {
3082 if (tls_segment == NULL)
3083 {
3084 gold_assert(parameters->errors()->error_count() > 0
3085 || issue_undefined_symbol_error(gsym));
3086 return;
3087 }
3088 value -= tls_segment->memsz();
3089 }
3090 }
3091 Relocate_functions<32, false>::rel32(view, value);
3092 break;
3093
3094 case elfcpp::R_386_TLS_IE: // Initial-exec
3095 case elfcpp::R_386_TLS_GOTIE:
3096 case elfcpp::R_386_TLS_IE_32:
3097 if (optimized_type == tls::TLSOPT_TO_LE)
3098 {
3099 if (tls_segment == NULL)
3100 {
3101 gold_assert(parameters->errors()->error_count() > 0
3102 || issue_undefined_symbol_error(gsym));
3103 return;
3104 }
3105 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3106 rel, r_type, value, view,
3107 view_size);
3108 break;
3109 }
3110 else if (optimized_type == tls::TLSOPT_NONE)
3111 {
3112 // Relocate the field with the offset of the GOT entry for
3113 // the tp-relative offset of the symbol.
3114 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
3115 ? GOT_TYPE_TLS_OFFSET
3116 : GOT_TYPE_TLS_NOFFSET);
3117 unsigned int got_offset;
3118 if (gsym != NULL)
3119 {
3120 gold_assert(gsym->has_got_offset(got_type));
3121 got_offset = gsym->got_offset(got_type);
3122 }
3123 else
3124 {
3125 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3126 gold_assert(object->local_has_got_offset(r_sym, got_type));
3127 got_offset = object->local_got_offset(r_sym, got_type);
3128 }
3129 // For the R_386_TLS_IE relocation, we need to apply the
3130 // absolute address of the GOT entry.
3131 if (r_type == elfcpp::R_386_TLS_IE)
3132 got_offset += target->got_plt_section()->address();
3133 // All GOT offsets are relative to the end of the GOT.
3134 got_offset -= target->got_size();
3135 Relocate_functions<32, false>::rel32(view, got_offset);
3136 break;
3137 }
3138 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3139 _("unsupported reloc %u"),
3140 r_type);
3141 break;
3142
3143 case elfcpp::R_386_TLS_LE: // Local-exec
3144 // If we're creating a shared library, a dynamic relocation will
3145 // have been created for this location, so do not apply it now.
3146 if (!parameters->options().shared())
3147 {
3148 if (tls_segment == NULL)
3149 {
3150 gold_assert(parameters->errors()->error_count() > 0
3151 || issue_undefined_symbol_error(gsym));
3152 return;
3153 }
3154 value -= tls_segment->memsz();
3155 Relocate_functions<32, false>::rel32(view, value);
3156 }
3157 break;
3158
3159 case elfcpp::R_386_TLS_LE_32:
3160 // If we're creating a shared library, a dynamic relocation will
3161 // have been created for this location, so do not apply it now.
3162 if (!parameters->options().shared())
3163 {
3164 if (tls_segment == NULL)
3165 {
3166 gold_assert(parameters->errors()->error_count() > 0
3167 || issue_undefined_symbol_error(gsym));
3168 return;
3169 }
3170 value = tls_segment->memsz() - value;
3171 Relocate_functions<32, false>::rel32(view, value);
3172 }
3173 break;
3174 }
3175 }
3176
3177 // Do a relocation in which we convert a TLS General-Dynamic to a
3178 // Local-Exec.
3179
3180 inline void
3181 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
3182 size_t relnum,
3183 Output_segment* tls_segment,
3184 const elfcpp::Rel<32, false>& rel,
3185 unsigned int,
3186 elfcpp::Elf_types<32>::Elf_Addr value,
3187 unsigned char* view,
3188 section_size_type view_size)
3189 {
3190 // leal foo(,%reg,1),%eax; call ___tls_get_addr
3191 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3192 // leal foo(%reg),%eax; call ___tls_get_addr
3193 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3194
3195 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3196 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3197
3198 unsigned char op1 = view[-1];
3199 unsigned char op2 = view[-2];
3200
3201 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3202 op2 == 0x8d || op2 == 0x04);
3203 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3204
3205 int roff = 5;
3206
3207 if (op2 == 0x04)
3208 {
3209 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3210 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3211 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3212 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3213 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3214 }
3215 else
3216 {
3217 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3218 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3219 if (rel.get_r_offset() + 9 < view_size
3220 && view[9] == 0x90)
3221 {
3222 // There is a trailing nop. Use the size byte subl.
3223 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3224 roff = 6;
3225 }
3226 else
3227 {
3228 // Use the five byte subl.
3229 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3230 }
3231 }
3232
3233 value = tls_segment->memsz() - value;
3234 Relocate_functions<32, false>::rel32(view + roff, value);
3235
3236 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3237 // We can skip it.
3238 this->skip_call_tls_get_addr_ = true;
3239 }
3240
3241 // Do a relocation in which we convert a TLS General-Dynamic to an
3242 // Initial-Exec.
3243
3244 inline void
3245 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
3246 size_t relnum,
3247 Output_segment*,
3248 const elfcpp::Rel<32, false>& rel,
3249 unsigned int,
3250 elfcpp::Elf_types<32>::Elf_Addr value,
3251 unsigned char* view,
3252 section_size_type view_size)
3253 {
3254 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
3255 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3256 // leal foo(%ebx),%eax; call ___tls_get_addr; nop
3257 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3258
3259 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3260 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3261
3262 unsigned char op1 = view[-1];
3263 unsigned char op2 = view[-2];
3264
3265 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3266 op2 == 0x8d || op2 == 0x04);
3267 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3268
3269 int roff;
3270
3271 if (op2 == 0x04)
3272 {
3273 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3274 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3275 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3276 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3277 roff = 5;
3278 }
3279 else
3280 {
3281 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 10);
3282 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3283 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3284 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[9] == 0x90);
3285 roff = 6;
3286 }
3287
3288 memcpy(view + roff - 8, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
3289 Relocate_functions<32, false>::rel32(view + roff, value);
3290
3291 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3292 // We can skip it.
3293 this->skip_call_tls_get_addr_ = true;
3294 }
3295
3296 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3297 // General-Dynamic to a Local-Exec.
3298
3299 inline void
3300 Target_i386::Relocate::tls_desc_gd_to_le(
3301 const Relocate_info<32, false>* relinfo,
3302 size_t relnum,
3303 Output_segment* tls_segment,
3304 const elfcpp::Rel<32, false>& rel,
3305 unsigned int r_type,
3306 elfcpp::Elf_types<32>::Elf_Addr value,
3307 unsigned char* view,
3308 section_size_type view_size)
3309 {
3310 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3311 {
3312 // leal foo@TLSDESC(%ebx), %eax
3313 // ==> leal foo@NTPOFF, %eax
3314 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3315 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3316 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3317 view[-2] == 0x8d && view[-1] == 0x83);
3318 view[-1] = 0x05;
3319 value -= tls_segment->memsz();
3320 Relocate_functions<32, false>::rel32(view, value);
3321 }
3322 else
3323 {
3324 // call *foo@TLSCALL(%eax)
3325 // ==> nop; nop
3326 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3327 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3328 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3329 view[0] == 0xff && view[1] == 0x10);
3330 view[0] = 0x66;
3331 view[1] = 0x90;
3332 }
3333 }
3334
3335 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3336 // General-Dynamic to an Initial-Exec.
3337
3338 inline void
3339 Target_i386::Relocate::tls_desc_gd_to_ie(
3340 const Relocate_info<32, false>* relinfo,
3341 size_t relnum,
3342 Output_segment*,
3343 const elfcpp::Rel<32, false>& rel,
3344 unsigned int r_type,
3345 elfcpp::Elf_types<32>::Elf_Addr value,
3346 unsigned char* view,
3347 section_size_type view_size)
3348 {
3349 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3350 {
3351 // leal foo@TLSDESC(%ebx), %eax
3352 // ==> movl foo@GOTNTPOFF(%ebx), %eax
3353 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3354 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3355 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3356 view[-2] == 0x8d && view[-1] == 0x83);
3357 view[-2] = 0x8b;
3358 Relocate_functions<32, false>::rel32(view, value);
3359 }
3360 else
3361 {
3362 // call *foo@TLSCALL(%eax)
3363 // ==> nop; nop
3364 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3365 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3366 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3367 view[0] == 0xff && view[1] == 0x10);
3368 view[0] = 0x66;
3369 view[1] = 0x90;
3370 }
3371 }
3372
3373 // Do a relocation in which we convert a TLS Local-Dynamic to a
3374 // Local-Exec.
3375
3376 inline void
3377 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
3378 size_t relnum,
3379 Output_segment*,
3380 const elfcpp::Rel<32, false>& rel,
3381 unsigned int,
3382 elfcpp::Elf_types<32>::Elf_Addr,
3383 unsigned char* view,
3384 section_size_type view_size)
3385 {
3386 // leal foo(%reg), %eax; call ___tls_get_addr
3387 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
3388
3389 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3390 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3391
3392 // FIXME: Does this test really always pass?
3393 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3394 view[-2] == 0x8d && view[-1] == 0x83);
3395
3396 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3397
3398 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
3399
3400 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3401 // We can skip it.
3402 this->skip_call_tls_get_addr_ = true;
3403 }
3404
3405 // Do a relocation in which we convert a TLS Initial-Exec to a
3406 // Local-Exec.
3407
3408 inline void
3409 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
3410 size_t relnum,
3411 Output_segment* tls_segment,
3412 const elfcpp::Rel<32, false>& rel,
3413 unsigned int r_type,
3414 elfcpp::Elf_types<32>::Elf_Addr value,
3415 unsigned char* view,
3416 section_size_type view_size)
3417 {
3418 // We have to actually change the instructions, which means that we
3419 // need to examine the opcodes to figure out which instruction we
3420 // are looking at.
3421 if (r_type == elfcpp::R_386_TLS_IE)
3422 {
3423 // movl %gs:XX,%eax ==> movl $YY,%eax
3424 // movl %gs:XX,%reg ==> movl $YY,%reg
3425 // addl %gs:XX,%reg ==> addl $YY,%reg
3426 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
3427 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3428
3429 unsigned char op1 = view[-1];
3430 if (op1 == 0xa1)
3431 {
3432 // movl XX,%eax ==> movl $YY,%eax
3433 view[-1] = 0xb8;
3434 }
3435 else
3436 {
3437 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3438
3439 unsigned char op2 = view[-2];
3440 if (op2 == 0x8b)
3441 {
3442 // movl XX,%reg ==> movl $YY,%reg
3443 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3444 (op1 & 0xc7) == 0x05);
3445 view[-2] = 0xc7;
3446 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3447 }
3448 else if (op2 == 0x03)
3449 {
3450 // addl XX,%reg ==> addl $YY,%reg
3451 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3452 (op1 & 0xc7) == 0x05);
3453 view[-2] = 0x81;
3454 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3455 }
3456 else
3457 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3458 }
3459 }
3460 else
3461 {
3462 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3463 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3464 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3465 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3466 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3467
3468 unsigned char op1 = view[-1];
3469 unsigned char op2 = view[-2];
3470 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3471 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
3472 if (op2 == 0x8b)
3473 {
3474 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3475 view[-2] = 0xc7;
3476 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3477 }
3478 else if (op2 == 0x2b)
3479 {
3480 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3481 view[-2] = 0x81;
3482 view[-1] = 0xe8 | ((op1 >> 3) & 7);
3483 }
3484 else if (op2 == 0x03)
3485 {
3486 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3487 view[-2] = 0x81;
3488 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3489 }
3490 else
3491 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3492 }
3493
3494 value = tls_segment->memsz() - value;
3495 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
3496 value = - value;
3497
3498 Relocate_functions<32, false>::rel32(view, value);
3499 }
3500
3501 // Relocate section data.
3502
3503 void
3504 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
3505 unsigned int sh_type,
3506 const unsigned char* prelocs,
3507 size_t reloc_count,
3508 Output_section* output_section,
3509 bool needs_special_offset_handling,
3510 unsigned char* view,
3511 elfcpp::Elf_types<32>::Elf_Addr address,
3512 section_size_type view_size,
3513 const Reloc_symbol_changes* reloc_symbol_changes)
3514 {
3515 gold_assert(sh_type == elfcpp::SHT_REL);
3516
3517 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
3518 Target_i386::Relocate, gold::Default_comdat_behavior>(
3519 relinfo,
3520 this,
3521 prelocs,
3522 reloc_count,
3523 output_section,
3524 needs_special_offset_handling,
3525 view,
3526 address,
3527 view_size,
3528 reloc_symbol_changes);
3529 }
3530
3531 // Return the size of a relocation while scanning during a relocatable
3532 // link.
3533
3534 unsigned int
3535 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
3536 unsigned int r_type,
3537 Relobj* object)
3538 {
3539 switch (r_type)
3540 {
3541 case elfcpp::R_386_NONE:
3542 case elfcpp::R_386_GNU_VTINHERIT:
3543 case elfcpp::R_386_GNU_VTENTRY:
3544 case elfcpp::R_386_TLS_GD: // Global-dynamic
3545 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3546 case elfcpp::R_386_TLS_DESC_CALL:
3547 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3548 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3549 case elfcpp::R_386_TLS_IE: // Initial-exec
3550 case elfcpp::R_386_TLS_IE_32:
3551 case elfcpp::R_386_TLS_GOTIE:
3552 case elfcpp::R_386_TLS_LE: // Local-exec
3553 case elfcpp::R_386_TLS_LE_32:
3554 return 0;
3555
3556 case elfcpp::R_386_32:
3557 case elfcpp::R_386_PC32:
3558 case elfcpp::R_386_GOT32:
3559 case elfcpp::R_386_PLT32:
3560 case elfcpp::R_386_GOTOFF:
3561 case elfcpp::R_386_GOTPC:
3562 return 4;
3563
3564 case elfcpp::R_386_16:
3565 case elfcpp::R_386_PC16:
3566 return 2;
3567
3568 case elfcpp::R_386_8:
3569 case elfcpp::R_386_PC8:
3570 return 1;
3571
3572 // These are relocations which should only be seen by the
3573 // dynamic linker, and should never be seen here.
3574 case elfcpp::R_386_COPY:
3575 case elfcpp::R_386_GLOB_DAT:
3576 case elfcpp::R_386_JUMP_SLOT:
3577 case elfcpp::R_386_RELATIVE:
3578 case elfcpp::R_386_IRELATIVE:
3579 case elfcpp::R_386_TLS_TPOFF:
3580 case elfcpp::R_386_TLS_DTPMOD32:
3581 case elfcpp::R_386_TLS_DTPOFF32:
3582 case elfcpp::R_386_TLS_TPOFF32:
3583 case elfcpp::R_386_TLS_DESC:
3584 object->error(_("unexpected reloc %u in object file"), r_type);
3585 return 0;
3586
3587 case elfcpp::R_386_32PLT:
3588 case elfcpp::R_386_TLS_GD_32:
3589 case elfcpp::R_386_TLS_GD_PUSH:
3590 case elfcpp::R_386_TLS_GD_CALL:
3591 case elfcpp::R_386_TLS_GD_POP:
3592 case elfcpp::R_386_TLS_LDM_32:
3593 case elfcpp::R_386_TLS_LDM_PUSH:
3594 case elfcpp::R_386_TLS_LDM_CALL:
3595 case elfcpp::R_386_TLS_LDM_POP:
3596 case elfcpp::R_386_USED_BY_INTEL_200:
3597 default:
3598 object->error(_("unsupported reloc %u in object file"), r_type);
3599 return 0;
3600 }
3601 }
3602
3603 // Scan the relocs during a relocatable link.
3604
3605 void
3606 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
3607 Layout* layout,
3608 Sized_relobj_file<32, false>* object,
3609 unsigned int data_shndx,
3610 unsigned int sh_type,
3611 const unsigned char* prelocs,
3612 size_t reloc_count,
3613 Output_section* output_section,
3614 bool needs_special_offset_handling,
3615 size_t local_symbol_count,
3616 const unsigned char* plocal_symbols,
3617 Relocatable_relocs* rr)
3618 {
3619 gold_assert(sh_type == elfcpp::SHT_REL);
3620
3621 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
3622 Relocatable_size_for_reloc> Scan_relocatable_relocs;
3623
3624 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
3625 Scan_relocatable_relocs>(
3626 symtab,
3627 layout,
3628 object,
3629 data_shndx,
3630 prelocs,
3631 reloc_count,
3632 output_section,
3633 needs_special_offset_handling,
3634 local_symbol_count,
3635 plocal_symbols,
3636 rr);
3637 }
3638
3639 // Emit relocations for a section.
3640
3641 void
3642 Target_i386::relocate_relocs(
3643 const Relocate_info<32, false>* relinfo,
3644 unsigned int sh_type,
3645 const unsigned char* prelocs,
3646 size_t reloc_count,
3647 Output_section* output_section,
3648 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
3649 const Relocatable_relocs* rr,
3650 unsigned char* view,
3651 elfcpp::Elf_types<32>::Elf_Addr view_address,
3652 section_size_type view_size,
3653 unsigned char* reloc_view,
3654 section_size_type reloc_view_size)
3655 {
3656 gold_assert(sh_type == elfcpp::SHT_REL);
3657
3658 gold::relocate_relocs<32, false, elfcpp::SHT_REL>(
3659 relinfo,
3660 prelocs,
3661 reloc_count,
3662 output_section,
3663 offset_in_output_section,
3664 rr,
3665 view,
3666 view_address,
3667 view_size,
3668 reloc_view,
3669 reloc_view_size);
3670 }
3671
3672 // Return the value to use for a dynamic which requires special
3673 // treatment. This is how we support equality comparisons of function
3674 // pointers across shared library boundaries, as described in the
3675 // processor specific ABI supplement.
3676
3677 uint64_t
3678 Target_i386::do_dynsym_value(const Symbol* gsym) const
3679 {
3680 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3681 return this->plt_address_for_global(gsym);
3682 }
3683
3684 // Return a string used to fill a code section with nops to take up
3685 // the specified length.
3686
3687 std::string
3688 Target_i386::do_code_fill(section_size_type length) const
3689 {
3690 if (length >= 16)
3691 {
3692 // Build a jmp instruction to skip over the bytes.
3693 unsigned char jmp[5];
3694 jmp[0] = 0xe9;
3695 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3696 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3697 + std::string(length - 5, static_cast<char>(0x90)));
3698 }
3699
3700 // Nop sequences of various lengths.
3701 const char nop1[1] = { '\x90' }; // nop
3702 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
3703 const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi
3704 const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3705 '\x00'};
3706 const char nop5[5] = { '\x90', '\x8d', '\x74', // nop
3707 '\x26', '\x00' }; // leal 0(%esi,1),%esi
3708 const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3709 '\x00', '\x00', '\x00' };
3710 const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3711 '\x00', '\x00', '\x00',
3712 '\x00' };
3713 const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop
3714 '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi
3715 '\x00', '\x00' };
3716 const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi
3717 '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi
3718 '\x00', '\x00', '\x00' };
3719 const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi
3720 '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi
3721 '\x00', '\x00', '\x00',
3722 '\x00' };
3723 const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3724 '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi
3725 '\x27', '\x00', '\x00',
3726 '\x00', '\x00' };
3727 const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3728 '\x00', '\x00', '\x00', // leal 0L(%edi),%edi
3729 '\x8d', '\xbf', '\x00',
3730 '\x00', '\x00', '\x00' };
3731 const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3732 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3733 '\x8d', '\xbc', '\x27',
3734 '\x00', '\x00', '\x00',
3735 '\x00' };
3736 const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3737 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3738 '\x00', '\x8d', '\xbc',
3739 '\x27', '\x00', '\x00',
3740 '\x00', '\x00' };
3741 const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15
3742 '\x90', '\x90', '\x90', // nop,nop,nop,...
3743 '\x90', '\x90', '\x90',
3744 '\x90', '\x90', '\x90',
3745 '\x90', '\x90', '\x90' };
3746
3747 const char* nops[16] = {
3748 NULL,
3749 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3750 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3751 };
3752
3753 return std::string(nops[length], length);
3754 }
3755
3756 // Return the value to use for the base of a DW_EH_PE_datarel offset
3757 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3758 // assembler can not write out the difference between two labels in
3759 // different sections, so instead of using a pc-relative value they
3760 // use an offset from the GOT.
3761
3762 uint64_t
3763 Target_i386::do_ehframe_datarel_base() const
3764 {
3765 gold_assert(this->global_offset_table_ != NULL);
3766 Symbol* sym = this->global_offset_table_;
3767 Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym);
3768 return ssym->value();
3769 }
3770
3771 // Return whether SYM should be treated as a call to a non-split
3772 // function. We don't want that to be true of a call to a
3773 // get_pc_thunk function.
3774
3775 bool
3776 Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
3777 {
3778 return (sym->type() == elfcpp::STT_FUNC
3779 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
3780 }
3781
3782 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3783 // compiled with -fsplit-stack. The function calls non-split-stack
3784 // code. We have to change the function so that it always ensures
3785 // that it has enough stack space to run some random function.
3786
3787 void
3788 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
3789 section_offset_type fnoffset,
3790 section_size_type fnsize,
3791 unsigned char* view,
3792 section_size_type view_size,
3793 std::string* from,
3794 std::string* to) const
3795 {
3796 // The function starts with a comparison of the stack pointer and a
3797 // field in the TCB. This is followed by a jump.
3798
3799 // cmp %gs:NN,%esp
3800 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
3801 && fnsize > 7)
3802 {
3803 // We will call __morestack if the carry flag is set after this
3804 // comparison. We turn the comparison into an stc instruction
3805 // and some nops.
3806 view[fnoffset] = '\xf9';
3807 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
3808 }
3809 // lea NN(%esp),%ecx
3810 // lea NN(%esp),%edx
3811 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
3812 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
3813 && fnsize > 7)
3814 {
3815 // This is loading an offset from the stack pointer for a
3816 // comparison. The offset is negative, so we decrease the
3817 // offset by the amount of space we need for the stack. This
3818 // means we will avoid calling __morestack if there happens to
3819 // be plenty of space on the stack already.
3820 unsigned char* pval = view + fnoffset + 3;
3821 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3822 val -= parameters->options().split_stack_adjust_size();
3823 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3824 }
3825 else
3826 {
3827 if (!object->has_no_split_stack())
3828 object->error(_("failed to match split-stack sequence at "
3829 "section %u offset %0zx"),
3830 shndx, static_cast<size_t>(fnoffset));
3831 return;
3832 }
3833
3834 // We have to change the function so that it calls
3835 // __morestack_non_split instead of __morestack. The former will
3836 // allocate additional stack space.
3837 *from = "__morestack";
3838 *to = "__morestack_non_split";
3839 }
3840
3841 // The selector for i386 object files. Note this is never instantiated
3842 // directly. It's only used in Target_selector_i386_nacl, below.
3843
3844 class Target_selector_i386 : public Target_selector_freebsd
3845 {
3846 public:
3847 Target_selector_i386()
3848 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
3849 "elf32-i386", "elf32-i386-freebsd",
3850 "elf_i386")
3851 { }
3852
3853 Target*
3854 do_instantiate_target()
3855 { return new Target_i386(); }
3856 };
3857
3858 // NaCl variant. It uses different PLT contents.
3859
3860 class Output_data_plt_i386_nacl : public Output_data_plt_i386
3861 {
3862 public:
3863 Output_data_plt_i386_nacl(Layout* layout,
3864 Output_data_got_plt_i386* got_plt,
3865 Output_data_space* got_irelative)
3866 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
3867 { }
3868
3869 protected:
3870 virtual unsigned int
3871 do_get_plt_entry_size() const
3872 { return plt_entry_size; }
3873
3874 virtual void
3875 do_add_eh_frame(Layout* layout)
3876 {
3877 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
3878 plt_eh_frame_fde, plt_eh_frame_fde_size);
3879 }
3880
3881 // The size of an entry in the PLT.
3882 static const int plt_entry_size = 64;
3883
3884 // The .eh_frame unwind information for the PLT.
3885 static const int plt_eh_frame_fde_size = 32;
3886 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
3887 };
3888
3889 class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl
3890 {
3891 public:
3892 Output_data_plt_i386_nacl_exec(Layout* layout,
3893 Output_data_got_plt_i386* got_plt,
3894 Output_data_space* got_irelative)
3895 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
3896 { }
3897
3898 protected:
3899 virtual void
3900 do_fill_first_plt_entry(unsigned char* pov,
3901 elfcpp::Elf_types<32>::Elf_Addr got_address);
3902
3903 virtual unsigned int
3904 do_fill_plt_entry(unsigned char* pov,
3905 elfcpp::Elf_types<32>::Elf_Addr got_address,
3906 unsigned int got_offset,
3907 unsigned int plt_offset,
3908 unsigned int plt_rel_offset);
3909
3910 private:
3911 // The first entry in the PLT for an executable.
3912 static const unsigned char first_plt_entry[plt_entry_size];
3913
3914 // Other entries in the PLT for an executable.
3915 static const unsigned char plt_entry[plt_entry_size];
3916 };
3917
3918 class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl
3919 {
3920 public:
3921 Output_data_plt_i386_nacl_dyn(Layout* layout,
3922 Output_data_got_plt_i386* got_plt,
3923 Output_data_space* got_irelative)
3924 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
3925 { }
3926
3927 protected:
3928 virtual void
3929 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
3930
3931 virtual unsigned int
3932 do_fill_plt_entry(unsigned char* pov,
3933 elfcpp::Elf_types<32>::Elf_Addr,
3934 unsigned int got_offset,
3935 unsigned int plt_offset,
3936 unsigned int plt_rel_offset);
3937
3938 private:
3939 // The first entry in the PLT for a shared object.
3940 static const unsigned char first_plt_entry[plt_entry_size];
3941
3942 // Other entries in the PLT for a shared object.
3943 static const unsigned char plt_entry[plt_entry_size];
3944 };
3945
3946 class Target_i386_nacl : public Target_i386
3947 {
3948 public:
3949 Target_i386_nacl()
3950 : Target_i386(&i386_nacl_info)
3951 { }
3952
3953 protected:
3954 virtual Output_data_plt_i386*
3955 do_make_data_plt(Layout* layout,
3956 Output_data_got_plt_i386* got_plt,
3957 Output_data_space* got_irelative,
3958 bool dyn)
3959 {
3960 if (dyn)
3961 return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative);
3962 else
3963 return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative);
3964 }
3965
3966 virtual std::string
3967 do_code_fill(section_size_type length) const;
3968
3969 private:
3970 static const Target::Target_info i386_nacl_info;
3971 };
3972
3973 const Target::Target_info Target_i386_nacl::i386_nacl_info =
3974 {
3975 32, // size
3976 false, // is_big_endian
3977 elfcpp::EM_386, // machine_code
3978 false, // has_make_symbol
3979 false, // has_resolve
3980 true, // has_code_fill
3981 true, // is_default_stack_executable
3982 true, // can_icf_inline_merge_sections
3983 '\0', // wrap_char
3984 "/lib/ld-nacl-x86-32.so.1", // dynamic_linker
3985 0x20000, // default_text_segment_address
3986 0x10000, // abi_pagesize (overridable by -z max-page-size)
3987 0x10000, // common_pagesize (overridable by -z common-page-size)
3988 true, // isolate_execinstr
3989 0x10000000, // rosegment_gap
3990 elfcpp::SHN_UNDEF, // small_common_shndx
3991 elfcpp::SHN_UNDEF, // large_common_shndx
3992 0, // small_common_section_flags
3993 0, // large_common_section_flags
3994 NULL, // attributes_section
3995 NULL, // attributes_vendor
3996 "_start" // entry_symbol_name
3997 };
3998
3999 #define NACLMASK 0xe0 // 32-byte alignment mask
4000
4001 const unsigned char
4002 Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] =
4003 {
4004 0xff, 0x35, // pushl contents of memory address
4005 0, 0, 0, 0, // replaced with address of .got + 4
4006 0x8b, 0x0d, // movl contents of address, %ecx
4007 0, 0, 0, 0, // replaced with address of .got + 8
4008 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4009 0xff, 0xe1, // jmp *%ecx
4010 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4011 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4012 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4013 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4014 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4015 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4016 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4017 0x90, 0x90, 0x90, 0x90, 0x90
4018 };
4019
4020 void
4021 Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry(
4022 unsigned char* pov,
4023 elfcpp::Elf_types<32>::Elf_Addr got_address)
4024 {
4025 memcpy(pov, first_plt_entry, plt_entry_size);
4026 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
4027 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
4028 }
4029
4030 // The first entry in the PLT for a shared object.
4031
4032 const unsigned char
4033 Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] =
4034 {
4035 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
4036 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx
4037 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4038 0xff, 0xe1, // jmp *%ecx
4039 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4040 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4041 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4042 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4043 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4044 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4045 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4046 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4047 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4048 0x90, 0x90, 0x90, 0x90, 0x90 // nops
4049 };
4050
4051 void
4052 Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry(
4053 unsigned char* pov,
4054 elfcpp::Elf_types<32>::Elf_Addr)
4055 {
4056 memcpy(pov, first_plt_entry, plt_entry_size);
4057 }
4058
4059 // Subsequent entries in the PLT for an executable.
4060
4061 const unsigned char
4062 Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] =
4063 {
4064 0x8b, 0x0d, // movl contents of address, %ecx */
4065 0, 0, 0, 0, // replaced with address of symbol in .got
4066 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4067 0xff, 0xe1, // jmp *%ecx
4068
4069 // Pad to the next 32-byte boundary with nop instructions.
4070 0x90,
4071 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4072 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4073
4074 // Lazy GOT entries point here (32-byte aligned).
4075 0x68, // pushl immediate
4076 0, 0, 0, 0, // replaced with offset into relocation table
4077 0xe9, // jmp relative
4078 0, 0, 0, 0, // replaced with offset to start of .plt
4079
4080 // Pad to the next 32-byte boundary with nop instructions.
4081 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4082 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4083 0x90, 0x90
4084 };
4085
4086 unsigned int
4087 Output_data_plt_i386_nacl_exec::do_fill_plt_entry(
4088 unsigned char* pov,
4089 elfcpp::Elf_types<32>::Elf_Addr got_address,
4090 unsigned int got_offset,
4091 unsigned int plt_offset,
4092 unsigned int plt_rel_offset)
4093 {
4094 memcpy(pov, plt_entry, plt_entry_size);
4095 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4096 got_address + got_offset);
4097 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4098 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4099 return 32;
4100 }
4101
4102 // Subsequent entries in the PLT for a shared object.
4103
4104 const unsigned char
4105 Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] =
4106 {
4107 0x8b, 0x8b, // movl offset(%ebx), %ecx
4108 0, 0, 0, 0, // replaced with offset of symbol in .got
4109 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx
4110 0xff, 0xe1, // jmp *%ecx
4111
4112 // Pad to the next 32-byte boundary with nop instructions.
4113 0x90,
4114 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4115 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4116
4117 // Lazy GOT entries point here (32-byte aligned).
4118 0x68, // pushl immediate
4119 0, 0, 0, 0, // replaced with offset into relocation table.
4120 0xe9, // jmp relative
4121 0, 0, 0, 0, // replaced with offset to start of .plt.
4122
4123 // Pad to the next 32-byte boundary with nop instructions.
4124 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4125 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4126 0x90, 0x90
4127 };
4128
4129 unsigned int
4130 Output_data_plt_i386_nacl_dyn::do_fill_plt_entry(
4131 unsigned char* pov,
4132 elfcpp::Elf_types<32>::Elf_Addr,
4133 unsigned int got_offset,
4134 unsigned int plt_offset,
4135 unsigned int plt_rel_offset)
4136 {
4137 memcpy(pov, plt_entry, plt_entry_size);
4138 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
4139 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4140 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4141 return 32;
4142 }
4143
4144 const unsigned char
4145 Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] =
4146 {
4147 0, 0, 0, 0, // Replaced with offset to .plt.
4148 0, 0, 0, 0, // Replaced with size of .plt.
4149 0, // Augmentation size.
4150 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
4151 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
4152 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
4153 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
4154 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
4155 13, // Block length.
4156 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
4157 elfcpp::DW_OP_breg8, 0, // Push %eip.
4158 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
4159 elfcpp::DW_OP_and, // & (%eip & 0x3f).
4160 elfcpp::DW_OP_const1u, 37, // Push 0x25.
4161 elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25)
4162 elfcpp::DW_OP_lit2, // Push 2.
4163 elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2)
4164 elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4
4165 elfcpp::DW_CFA_nop, // Align to 32 bytes.
4166 elfcpp::DW_CFA_nop
4167 };
4168
4169 // Return a string used to fill a code section with nops.
4170 // For NaCl, long NOPs are only valid if they do not cross
4171 // bundle alignment boundaries, so keep it simple with one-byte NOPs.
4172 std::string
4173 Target_i386_nacl::do_code_fill(section_size_type length) const
4174 {
4175 return std::string(length, static_cast<char>(0x90));
4176 }
4177
4178 // The selector for i386-nacl object files.
4179
4180 class Target_selector_i386_nacl
4181 : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl>
4182 {
4183 public:
4184 Target_selector_i386_nacl()
4185 : Target_selector_nacl<Target_selector_i386,
4186 Target_i386_nacl>("x86-32",
4187 "elf32-i386-nacl",
4188 "elf_i386_nacl")
4189 { }
4190 };
4191
4192 Target_selector_i386_nacl target_selector_i386;
4193
4194 } // End anonymous namespace.
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