Pass relocations to Target::do_calls_non_split.
[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 unsigned char* view,
441 elfcpp::Elf_types<32>::Elf_Addr view_address,
442 section_size_type view_size,
443 unsigned char* reloc_view,
444 section_size_type reloc_view_size);
445
446 // Return a string used to fill a code section with nops.
447 std::string
448 do_code_fill(section_size_type length) const;
449
450 // Return whether SYM is defined by the ABI.
451 bool
452 do_is_defined_by_abi(const Symbol* sym) const
453 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
454
455 // Return whether a symbol name implies a local label. The UnixWare
456 // 2.1 cc generates temporary symbols that start with .X, so we
457 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
458 // If so, we should move the .X recognition into
459 // Target::do_is_local_label_name.
460 bool
461 do_is_local_label_name(const char* name) const
462 {
463 if (name[0] == '.' && name[1] == 'X')
464 return true;
465 return Target::do_is_local_label_name(name);
466 }
467
468 // Return the PLT address to use for a global symbol.
469 uint64_t
470 do_plt_address_for_global(const Symbol* gsym) const
471 { return this->plt_section()->address_for_global(gsym); }
472
473 uint64_t
474 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
475 { return this->plt_section()->address_for_local(relobj, symndx); }
476
477 // We can tell whether we take the address of a function.
478 inline bool
479 do_can_check_for_function_pointers() const
480 { return true; }
481
482 // Return the base for a DW_EH_PE_datarel encoding.
483 uint64_t
484 do_ehframe_datarel_base() const;
485
486 // Return whether SYM is call to a non-split function.
487 bool
488 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
489
490 // Adjust -fsplit-stack code which calls non-split-stack code.
491 void
492 do_calls_non_split(Relobj* object, unsigned int shndx,
493 section_offset_type fnoffset, section_size_type fnsize,
494 const unsigned char* prelocs, size_t reloc_count,
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>*, unsigned int,
638 Target_i386*, Output_section*, size_t, const unsigned char*,
639 const Sized_symbol<32>*, const Symbol_value<32>*,
640 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
641 section_size_type);
642
643 private:
644 // Do a TLS relocation.
645 inline void
646 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
647 size_t relnum, const elfcpp::Rel<32, false>&,
648 unsigned int r_type, const Sized_symbol<32>*,
649 const Symbol_value<32>*,
650 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
651 section_size_type);
652
653 // Do a TLS General-Dynamic to Initial-Exec transition.
654 inline void
655 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
656 Output_segment* tls_segment,
657 const elfcpp::Rel<32, false>&, unsigned int r_type,
658 elfcpp::Elf_types<32>::Elf_Addr value,
659 unsigned char* view,
660 section_size_type view_size);
661
662 // Do a TLS General-Dynamic to Local-Exec transition.
663 inline void
664 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
665 Output_segment* tls_segment,
666 const elfcpp::Rel<32, false>&, unsigned int r_type,
667 elfcpp::Elf_types<32>::Elf_Addr value,
668 unsigned char* view,
669 section_size_type view_size);
670
671 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
672 // transition.
673 inline void
674 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
675 Output_segment* tls_segment,
676 const elfcpp::Rel<32, false>&, unsigned int r_type,
677 elfcpp::Elf_types<32>::Elf_Addr value,
678 unsigned char* view,
679 section_size_type view_size);
680
681 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
682 // transition.
683 inline void
684 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
685 Output_segment* tls_segment,
686 const elfcpp::Rel<32, false>&, unsigned int r_type,
687 elfcpp::Elf_types<32>::Elf_Addr value,
688 unsigned char* view,
689 section_size_type view_size);
690
691 // Do a TLS Local-Dynamic to Local-Exec transition.
692 inline void
693 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
694 Output_segment* tls_segment,
695 const elfcpp::Rel<32, false>&, unsigned int r_type,
696 elfcpp::Elf_types<32>::Elf_Addr value,
697 unsigned char* view,
698 section_size_type view_size);
699
700 // Do a TLS Initial-Exec to Local-Exec transition.
701 static inline void
702 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
703 Output_segment* tls_segment,
704 const elfcpp::Rel<32, false>&, unsigned int r_type,
705 elfcpp::Elf_types<32>::Elf_Addr value,
706 unsigned char* view,
707 section_size_type view_size);
708
709 // We need to keep track of which type of local dynamic relocation
710 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
711 enum Local_dynamic_type
712 {
713 LOCAL_DYNAMIC_NONE,
714 LOCAL_DYNAMIC_SUN,
715 LOCAL_DYNAMIC_GNU
716 };
717
718 // This is set if we should skip the next reloc, which should be a
719 // PLT32 reloc against ___tls_get_addr.
720 bool skip_call_tls_get_addr_;
721 // The type of local dynamic relocation we have seen in the section
722 // being relocated, if any.
723 Local_dynamic_type local_dynamic_type_;
724 };
725
726 // A class which returns the size required for a relocation type,
727 // used while scanning relocs during a relocatable link.
728 class Relocatable_size_for_reloc
729 {
730 public:
731 unsigned int
732 get_size_for_reloc(unsigned int, Relobj*);
733 };
734
735 // Adjust TLS relocation type based on the options and whether this
736 // is a local symbol.
737 static tls::Tls_optimization
738 optimize_tls_reloc(bool is_final, int r_type);
739
740 // Check if relocation against this symbol is a candidate for
741 // conversion from
742 // mov foo@GOT(%reg), %reg
743 // to
744 // lea foo@GOTOFF(%reg), %reg.
745 static bool
746 can_convert_mov_to_lea(const Symbol* gsym)
747 {
748 gold_assert(gsym != NULL);
749 return (gsym->type() != elfcpp::STT_GNU_IFUNC
750 && !gsym->is_undefined ()
751 && !gsym->is_from_dynobj()
752 && !gsym->is_preemptible()
753 && (!parameters->options().shared()
754 || (gsym->visibility() != elfcpp::STV_DEFAULT
755 && gsym->visibility() != elfcpp::STV_PROTECTED)
756 || parameters->options().Bsymbolic())
757 && strcmp(gsym->name(), "_DYNAMIC") != 0);
758 }
759
760 // Get the GOT section, creating it if necessary.
761 Output_data_got<32, false>*
762 got_section(Symbol_table*, Layout*);
763
764 // Get the GOT PLT section.
765 Output_data_got_plt_i386*
766 got_plt_section() const
767 {
768 gold_assert(this->got_plt_ != NULL);
769 return this->got_plt_;
770 }
771
772 // Get the GOT section for TLSDESC entries.
773 Output_data_got<32, false>*
774 got_tlsdesc_section() const
775 {
776 gold_assert(this->got_tlsdesc_ != NULL);
777 return this->got_tlsdesc_;
778 }
779
780 // Create the PLT section.
781 void
782 make_plt_section(Symbol_table* symtab, Layout* layout);
783
784 // Create a PLT entry for a global symbol.
785 void
786 make_plt_entry(Symbol_table*, Layout*, Symbol*);
787
788 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
789 void
790 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
791 Sized_relobj_file<32, false>* relobj,
792 unsigned int local_sym_index);
793
794 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
795 void
796 define_tls_base_symbol(Symbol_table*, Layout*);
797
798 // Create a GOT entry for the TLS module index.
799 unsigned int
800 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
801 Sized_relobj_file<32, false>* object);
802
803 // Get the PLT section.
804 Output_data_plt_i386*
805 plt_section() const
806 {
807 gold_assert(this->plt_ != NULL);
808 return this->plt_;
809 }
810
811 // Get the dynamic reloc section, creating it if necessary.
812 Reloc_section*
813 rel_dyn_section(Layout*);
814
815 // Get the section to use for TLS_DESC relocations.
816 Reloc_section*
817 rel_tls_desc_section(Layout*) const;
818
819 // Get the section to use for IRELATIVE relocations.
820 Reloc_section*
821 rel_irelative_section(Layout*);
822
823 // Add a potential copy relocation.
824 void
825 copy_reloc(Symbol_table* symtab, Layout* layout,
826 Sized_relobj_file<32, false>* object,
827 unsigned int shndx, Output_section* output_section,
828 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
829 {
830 unsigned int r_type = elfcpp::elf_r_type<32>(reloc.get_r_info());
831 this->copy_relocs_.copy_reloc(symtab, layout,
832 symtab->get_sized_symbol<32>(sym),
833 object, shndx, output_section,
834 r_type, reloc.get_r_offset(), 0,
835 this->rel_dyn_section(layout));
836 }
837
838 // Information about this specific target which we pass to the
839 // general Target structure.
840 static const Target::Target_info i386_info;
841
842 // The types of GOT entries needed for this platform.
843 // These values are exposed to the ABI in an incremental link.
844 // Do not renumber existing values without changing the version
845 // number of the .gnu_incremental_inputs section.
846 enum Got_type
847 {
848 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
849 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
850 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
851 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
852 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
853 };
854
855 // The GOT section.
856 Output_data_got<32, false>* got_;
857 // The PLT section.
858 Output_data_plt_i386* plt_;
859 // The GOT PLT section.
860 Output_data_got_plt_i386* got_plt_;
861 // The GOT section for IRELATIVE relocations.
862 Output_data_space* got_irelative_;
863 // The GOT section for TLSDESC relocations.
864 Output_data_got<32, false>* got_tlsdesc_;
865 // The _GLOBAL_OFFSET_TABLE_ symbol.
866 Symbol* global_offset_table_;
867 // The dynamic reloc section.
868 Reloc_section* rel_dyn_;
869 // The section to use for IRELATIVE relocs.
870 Reloc_section* rel_irelative_;
871 // Relocs saved to avoid a COPY reloc.
872 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
873 // Offset of the GOT entry for the TLS module index.
874 unsigned int got_mod_index_offset_;
875 // True if the _TLS_MODULE_BASE_ symbol has been defined.
876 bool tls_base_symbol_defined_;
877 };
878
879 const Target::Target_info Target_i386::i386_info =
880 {
881 32, // size
882 false, // is_big_endian
883 elfcpp::EM_386, // machine_code
884 false, // has_make_symbol
885 false, // has_resolve
886 true, // has_code_fill
887 true, // is_default_stack_executable
888 true, // can_icf_inline_merge_sections
889 '\0', // wrap_char
890 "/usr/lib/libc.so.1", // dynamic_linker
891 0x08048000, // default_text_segment_address
892 0x1000, // abi_pagesize (overridable by -z max-page-size)
893 0x1000, // common_pagesize (overridable by -z common-page-size)
894 false, // isolate_execinstr
895 0, // rosegment_gap
896 elfcpp::SHN_UNDEF, // small_common_shndx
897 elfcpp::SHN_UNDEF, // large_common_shndx
898 0, // small_common_section_flags
899 0, // large_common_section_flags
900 NULL, // attributes_section
901 NULL, // attributes_vendor
902 "_start", // entry_symbol_name
903 32, // hash_entry_size
904 };
905
906 // Get the GOT section, creating it if necessary.
907
908 Output_data_got<32, false>*
909 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
910 {
911 if (this->got_ == NULL)
912 {
913 gold_assert(symtab != NULL && layout != NULL);
914
915 this->got_ = new Output_data_got<32, false>();
916
917 // When using -z now, we can treat .got.plt as a relro section.
918 // Without -z now, it is modified after program startup by lazy
919 // PLT relocations.
920 bool is_got_plt_relro = parameters->options().now();
921 Output_section_order got_order = (is_got_plt_relro
922 ? ORDER_RELRO
923 : ORDER_RELRO_LAST);
924 Output_section_order got_plt_order = (is_got_plt_relro
925 ? ORDER_RELRO
926 : ORDER_NON_RELRO_FIRST);
927
928 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
929 (elfcpp::SHF_ALLOC
930 | elfcpp::SHF_WRITE),
931 this->got_, got_order, true);
932
933 this->got_plt_ = new Output_data_got_plt_i386(layout);
934 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
935 (elfcpp::SHF_ALLOC
936 | elfcpp::SHF_WRITE),
937 this->got_plt_, got_plt_order,
938 is_got_plt_relro);
939
940 // The first three entries are reserved.
941 this->got_plt_->set_current_data_size(3 * 4);
942
943 if (!is_got_plt_relro)
944 {
945 // Those bytes can go into the relro segment.
946 layout->increase_relro(3 * 4);
947 }
948
949 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
950 this->global_offset_table_ =
951 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
952 Symbol_table::PREDEFINED,
953 this->got_plt_,
954 0, 0, elfcpp::STT_OBJECT,
955 elfcpp::STB_LOCAL,
956 elfcpp::STV_HIDDEN, 0,
957 false, false);
958
959 // If there are any IRELATIVE relocations, they get GOT entries
960 // in .got.plt after the jump slot relocations.
961 this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT");
962 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
963 (elfcpp::SHF_ALLOC
964 | elfcpp::SHF_WRITE),
965 this->got_irelative_,
966 got_plt_order, is_got_plt_relro);
967
968 // If there are any TLSDESC relocations, they get GOT entries in
969 // .got.plt after the jump slot entries.
970 this->got_tlsdesc_ = new Output_data_got<32, false>();
971 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
972 (elfcpp::SHF_ALLOC
973 | elfcpp::SHF_WRITE),
974 this->got_tlsdesc_,
975 got_plt_order, is_got_plt_relro);
976 }
977
978 return this->got_;
979 }
980
981 // Get the dynamic reloc section, creating it if necessary.
982
983 Target_i386::Reloc_section*
984 Target_i386::rel_dyn_section(Layout* layout)
985 {
986 if (this->rel_dyn_ == NULL)
987 {
988 gold_assert(layout != NULL);
989 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
990 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
991 elfcpp::SHF_ALLOC, this->rel_dyn_,
992 ORDER_DYNAMIC_RELOCS, false);
993 }
994 return this->rel_dyn_;
995 }
996
997 // Get the section to use for IRELATIVE relocs, creating it if
998 // necessary. These go in .rel.dyn, but only after all other dynamic
999 // relocations. They need to follow the other dynamic relocations so
1000 // that they can refer to global variables initialized by those
1001 // relocs.
1002
1003 Target_i386::Reloc_section*
1004 Target_i386::rel_irelative_section(Layout* layout)
1005 {
1006 if (this->rel_irelative_ == NULL)
1007 {
1008 // Make sure we have already create the dynamic reloc section.
1009 this->rel_dyn_section(layout);
1010 this->rel_irelative_ = new Reloc_section(false);
1011 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
1012 elfcpp::SHF_ALLOC, this->rel_irelative_,
1013 ORDER_DYNAMIC_RELOCS, false);
1014 gold_assert(this->rel_dyn_->output_section()
1015 == this->rel_irelative_->output_section());
1016 }
1017 return this->rel_irelative_;
1018 }
1019
1020 // Write the first three reserved words of the .got.plt section.
1021 // The remainder of the section is written while writing the PLT
1022 // in Output_data_plt_i386::do_write.
1023
1024 void
1025 Output_data_got_plt_i386::do_write(Output_file* of)
1026 {
1027 // The first entry in the GOT is the address of the .dynamic section
1028 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1029 // We saved space for them when we created the section in
1030 // Target_i386::got_section.
1031 const off_t got_file_offset = this->offset();
1032 gold_assert(this->data_size() >= 12);
1033 unsigned char* const got_view = of->get_output_view(got_file_offset, 12);
1034 Output_section* dynamic = this->layout_->dynamic_section();
1035 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1036 elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr);
1037 memset(got_view + 4, 0, 8);
1038 of->write_output_view(got_file_offset, 12, got_view);
1039 }
1040
1041 // Create the PLT section. The ordinary .got section is an argument,
1042 // since we need to refer to the start. We also create our own .got
1043 // section just for PLT entries.
1044
1045 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
1046 uint64_t addralign,
1047 Output_data_got_plt_i386* got_plt,
1048 Output_data_space* got_irelative)
1049 : Output_section_data(addralign),
1050 tls_desc_rel_(NULL), irelative_rel_(NULL), got_plt_(got_plt),
1051 got_irelative_(got_irelative), count_(0), irelative_count_(0),
1052 global_ifuncs_(), local_ifuncs_()
1053 {
1054 this->rel_ = new Reloc_section(false);
1055 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1056 elfcpp::SHF_ALLOC, this->rel_,
1057 ORDER_DYNAMIC_PLT_RELOCS, false);
1058 }
1059
1060 void
1061 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
1062 {
1063 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
1064 // linker, and so do we.
1065 os->set_entsize(4);
1066 }
1067
1068 // Add an entry to the PLT.
1069
1070 void
1071 Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
1072 Symbol* gsym)
1073 {
1074 gold_assert(!gsym->has_plt_offset());
1075
1076 // Every PLT entry needs a reloc.
1077 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1078 && gsym->can_use_relative_reloc(false))
1079 {
1080 gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size());
1081 ++this->irelative_count_;
1082 section_offset_type got_offset =
1083 this->got_irelative_->current_data_size();
1084 this->got_irelative_->set_current_data_size(got_offset + 4);
1085 Reloc_section* rel = this->rel_irelative(symtab, layout);
1086 rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
1087 this->got_irelative_, got_offset);
1088 struct Global_ifunc gi;
1089 gi.sym = gsym;
1090 gi.got_offset = got_offset;
1091 this->global_ifuncs_.push_back(gi);
1092 }
1093 else
1094 {
1095 // When setting the PLT offset we skip the initial reserved PLT
1096 // entry.
1097 gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size());
1098
1099 ++this->count_;
1100
1101 section_offset_type got_offset = this->got_plt_->current_data_size();
1102
1103 // Every PLT entry needs a GOT entry which points back to the
1104 // PLT entry (this will be changed by the dynamic linker,
1105 // normally lazily when the function is called).
1106 this->got_plt_->set_current_data_size(got_offset + 4);
1107
1108 gsym->set_needs_dynsym_entry();
1109 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
1110 got_offset);
1111 }
1112
1113 // Note that we don't need to save the symbol. The contents of the
1114 // PLT are independent of which symbols are used. The symbols only
1115 // appear in the relocations.
1116 }
1117
1118 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1119 // the PLT offset.
1120
1121 unsigned int
1122 Output_data_plt_i386::add_local_ifunc_entry(
1123 Symbol_table* symtab,
1124 Layout* layout,
1125 Sized_relobj_file<32, false>* relobj,
1126 unsigned int local_sym_index)
1127 {
1128 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1129 ++this->irelative_count_;
1130
1131 section_offset_type got_offset = this->got_irelative_->current_data_size();
1132
1133 // Every PLT entry needs a GOT entry which points back to the PLT
1134 // entry.
1135 this->got_irelative_->set_current_data_size(got_offset + 4);
1136
1137 // Every PLT entry needs a reloc.
1138 Reloc_section* rel = this->rel_irelative(symtab, layout);
1139 rel->add_symbolless_local_addend(relobj, local_sym_index,
1140 elfcpp::R_386_IRELATIVE,
1141 this->got_irelative_, got_offset);
1142
1143 struct Local_ifunc li;
1144 li.object = relobj;
1145 li.local_sym_index = local_sym_index;
1146 li.got_offset = got_offset;
1147 this->local_ifuncs_.push_back(li);
1148
1149 return plt_offset;
1150 }
1151
1152 // Return where the TLS_DESC relocations should go, creating it if
1153 // necessary. These follow the JUMP_SLOT relocations.
1154
1155 Output_data_plt_i386::Reloc_section*
1156 Output_data_plt_i386::rel_tls_desc(Layout* layout)
1157 {
1158 if (this->tls_desc_rel_ == NULL)
1159 {
1160 this->tls_desc_rel_ = new Reloc_section(false);
1161 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1162 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
1163 ORDER_DYNAMIC_PLT_RELOCS, false);
1164 gold_assert(this->tls_desc_rel_->output_section()
1165 == this->rel_->output_section());
1166 }
1167 return this->tls_desc_rel_;
1168 }
1169
1170 // Return where the IRELATIVE relocations should go in the PLT. These
1171 // follow the JUMP_SLOT and TLS_DESC relocations.
1172
1173 Output_data_plt_i386::Reloc_section*
1174 Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
1175 {
1176 if (this->irelative_rel_ == NULL)
1177 {
1178 // Make sure we have a place for the TLS_DESC relocations, in
1179 // case we see any later on.
1180 this->rel_tls_desc(layout);
1181 this->irelative_rel_ = new Reloc_section(false);
1182 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1183 elfcpp::SHF_ALLOC, this->irelative_rel_,
1184 ORDER_DYNAMIC_PLT_RELOCS, false);
1185 gold_assert(this->irelative_rel_->output_section()
1186 == this->rel_->output_section());
1187
1188 if (parameters->doing_static_link())
1189 {
1190 // A statically linked executable will only have a .rel.plt
1191 // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
1192 // symbols. The library will use these symbols to locate
1193 // the IRELATIVE relocs at program startup time.
1194 symtab->define_in_output_data("__rel_iplt_start", NULL,
1195 Symbol_table::PREDEFINED,
1196 this->irelative_rel_, 0, 0,
1197 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1198 elfcpp::STV_HIDDEN, 0, false, true);
1199 symtab->define_in_output_data("__rel_iplt_end", NULL,
1200 Symbol_table::PREDEFINED,
1201 this->irelative_rel_, 0, 0,
1202 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1203 elfcpp::STV_HIDDEN, 0, true, true);
1204 }
1205 }
1206 return this->irelative_rel_;
1207 }
1208
1209 // Return the PLT address to use for a global symbol.
1210
1211 uint64_t
1212 Output_data_plt_i386::address_for_global(const Symbol* gsym)
1213 {
1214 uint64_t offset = 0;
1215 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1216 && gsym->can_use_relative_reloc(false))
1217 offset = (this->count_ + 1) * this->get_plt_entry_size();
1218 return this->address() + offset + gsym->plt_offset();
1219 }
1220
1221 // Return the PLT address to use for a local symbol. These are always
1222 // IRELATIVE relocs.
1223
1224 uint64_t
1225 Output_data_plt_i386::address_for_local(const Relobj* object,
1226 unsigned int r_sym)
1227 {
1228 return (this->address()
1229 + (this->count_ + 1) * this->get_plt_entry_size()
1230 + object->local_plt_offset(r_sym));
1231 }
1232
1233 // The first entry in the PLT for an executable.
1234
1235 const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] =
1236 {
1237 0xff, 0x35, // pushl contents of memory address
1238 0, 0, 0, 0, // replaced with address of .got + 4
1239 0xff, 0x25, // jmp indirect
1240 0, 0, 0, 0, // replaced with address of .got + 8
1241 0, 0, 0, 0 // unused
1242 };
1243
1244 void
1245 Output_data_plt_i386_exec::do_fill_first_plt_entry(
1246 unsigned char* pov,
1247 elfcpp::Elf_types<32>::Elf_Addr got_address)
1248 {
1249 memcpy(pov, first_plt_entry, plt_entry_size);
1250 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
1251 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
1252 }
1253
1254 // The first entry in the PLT for a shared object.
1255
1256 const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] =
1257 {
1258 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
1259 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
1260 0, 0, 0, 0 // unused
1261 };
1262
1263 void
1264 Output_data_plt_i386_dyn::do_fill_first_plt_entry(
1265 unsigned char* pov,
1266 elfcpp::Elf_types<32>::Elf_Addr)
1267 {
1268 memcpy(pov, first_plt_entry, plt_entry_size);
1269 }
1270
1271 // Subsequent entries in the PLT for an executable.
1272
1273 const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] =
1274 {
1275 0xff, 0x25, // jmp indirect
1276 0, 0, 0, 0, // replaced with address of symbol in .got
1277 0x68, // pushl immediate
1278 0, 0, 0, 0, // replaced with offset into relocation table
1279 0xe9, // jmp relative
1280 0, 0, 0, 0 // replaced with offset to start of .plt
1281 };
1282
1283 unsigned int
1284 Output_data_plt_i386_exec::do_fill_plt_entry(
1285 unsigned char* pov,
1286 elfcpp::Elf_types<32>::Elf_Addr got_address,
1287 unsigned int got_offset,
1288 unsigned int plt_offset,
1289 unsigned int plt_rel_offset)
1290 {
1291 memcpy(pov, plt_entry, plt_entry_size);
1292 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1293 got_address + got_offset);
1294 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1295 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1296 return 6;
1297 }
1298
1299 // Subsequent entries in the PLT for a shared object.
1300
1301 const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] =
1302 {
1303 0xff, 0xa3, // jmp *offset(%ebx)
1304 0, 0, 0, 0, // replaced with offset of symbol in .got
1305 0x68, // pushl immediate
1306 0, 0, 0, 0, // replaced with offset into relocation table
1307 0xe9, // jmp relative
1308 0, 0, 0, 0 // replaced with offset to start of .plt
1309 };
1310
1311 unsigned int
1312 Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov,
1313 elfcpp::Elf_types<32>::Elf_Addr,
1314 unsigned int got_offset,
1315 unsigned int plt_offset,
1316 unsigned int plt_rel_offset)
1317 {
1318 memcpy(pov, plt_entry, plt_entry_size);
1319 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
1320 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1321 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1322 return 6;
1323 }
1324
1325 // The .eh_frame unwind information for the PLT.
1326
1327 const unsigned char
1328 Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1329 {
1330 1, // CIE version.
1331 'z', // Augmentation: augmentation size included.
1332 'R', // Augmentation: FDE encoding included.
1333 '\0', // End of augmentation string.
1334 1, // Code alignment factor.
1335 0x7c, // Data alignment factor.
1336 8, // Return address column.
1337 1, // Augmentation size.
1338 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1339 | elfcpp::DW_EH_PE_sdata4),
1340 elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
1341 elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
1342 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1343 elfcpp::DW_CFA_nop
1344 };
1345
1346 const unsigned char
1347 Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1348 {
1349 0, 0, 0, 0, // Replaced with offset to .plt.
1350 0, 0, 0, 0, // Replaced with size of .plt.
1351 0, // Augmentation size.
1352 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
1353 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1354 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
1355 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1356 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1357 11, // Block length.
1358 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
1359 elfcpp::DW_OP_breg8, 0, // Push %eip.
1360 elfcpp::DW_OP_lit15, // Push 0xf.
1361 elfcpp::DW_OP_and, // & (%eip & 0xf).
1362 elfcpp::DW_OP_lit11, // Push 0xb.
1363 elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
1364 elfcpp::DW_OP_lit2, // Push 2.
1365 elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
1366 elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4
1367 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1368 elfcpp::DW_CFA_nop,
1369 elfcpp::DW_CFA_nop,
1370 elfcpp::DW_CFA_nop
1371 };
1372
1373 // Write out the PLT. This uses the hand-coded instructions above,
1374 // and adjusts them as needed. This is all specified by the i386 ELF
1375 // Processor Supplement.
1376
1377 void
1378 Output_data_plt_i386::do_write(Output_file* of)
1379 {
1380 const off_t offset = this->offset();
1381 const section_size_type oview_size =
1382 convert_to_section_size_type(this->data_size());
1383 unsigned char* const oview = of->get_output_view(offset, oview_size);
1384
1385 const off_t got_file_offset = this->got_plt_->offset();
1386 gold_assert(parameters->incremental_update()
1387 || (got_file_offset + this->got_plt_->data_size()
1388 == this->got_irelative_->offset()));
1389 const section_size_type got_size =
1390 convert_to_section_size_type(this->got_plt_->data_size()
1391 + this->got_irelative_->data_size());
1392
1393 unsigned char* const got_view = of->get_output_view(got_file_offset,
1394 got_size);
1395
1396 unsigned char* pov = oview;
1397
1398 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
1399 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
1400
1401 this->fill_first_plt_entry(pov, got_address);
1402 pov += this->get_plt_entry_size();
1403
1404 // The first three entries in the GOT are reserved, and are written
1405 // by Output_data_got_plt_i386::do_write.
1406 unsigned char* got_pov = got_view + 12;
1407
1408 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
1409
1410 unsigned int plt_offset = this->get_plt_entry_size();
1411 unsigned int plt_rel_offset = 0;
1412 unsigned int got_offset = 12;
1413 const unsigned int count = this->count_ + this->irelative_count_;
1414 for (unsigned int i = 0;
1415 i < count;
1416 ++i,
1417 pov += this->get_plt_entry_size(),
1418 got_pov += 4,
1419 plt_offset += this->get_plt_entry_size(),
1420 plt_rel_offset += rel_size,
1421 got_offset += 4)
1422 {
1423 // Set and adjust the PLT entry itself.
1424 unsigned int lazy_offset = this->fill_plt_entry(pov,
1425 got_address,
1426 got_offset,
1427 plt_offset,
1428 plt_rel_offset);
1429
1430 // Set the entry in the GOT.
1431 elfcpp::Swap<32, false>::writeval(got_pov,
1432 plt_address + plt_offset + lazy_offset);
1433 }
1434
1435 // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
1436 // the GOT to point to the actual symbol value, rather than point to
1437 // the PLT entry. That will let the dynamic linker call the right
1438 // function when resolving IRELATIVE relocations.
1439 unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
1440 for (std::vector<Global_ifunc>::const_iterator p =
1441 this->global_ifuncs_.begin();
1442 p != this->global_ifuncs_.end();
1443 ++p)
1444 {
1445 const Sized_symbol<32>* ssym =
1446 static_cast<const Sized_symbol<32>*>(p->sym);
1447 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1448 ssym->value());
1449 }
1450
1451 for (std::vector<Local_ifunc>::const_iterator p =
1452 this->local_ifuncs_.begin();
1453 p != this->local_ifuncs_.end();
1454 ++p)
1455 {
1456 const Symbol_value<32>* psymval =
1457 p->object->local_symbol(p->local_sym_index);
1458 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1459 psymval->value(p->object, 0));
1460 }
1461
1462 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1463 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1464
1465 of->write_output_view(offset, oview_size, oview);
1466 of->write_output_view(got_file_offset, got_size, got_view);
1467 }
1468
1469 // Create the PLT section.
1470
1471 void
1472 Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
1473 {
1474 if (this->plt_ == NULL)
1475 {
1476 // Create the GOT sections first.
1477 this->got_section(symtab, layout);
1478
1479 const bool dyn = parameters->options().output_is_position_independent();
1480 this->plt_ = this->make_data_plt(layout,
1481 this->got_plt_,
1482 this->got_irelative_,
1483 dyn);
1484
1485 // Add unwind information if requested.
1486 if (parameters->options().ld_generated_unwind_info())
1487 this->plt_->add_eh_frame(layout);
1488
1489 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1490 (elfcpp::SHF_ALLOC
1491 | elfcpp::SHF_EXECINSTR),
1492 this->plt_, ORDER_PLT, false);
1493
1494 // Make the sh_info field of .rel.plt point to .plt.
1495 Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
1496 rel_plt_os->set_info_section(this->plt_->output_section());
1497 }
1498 }
1499
1500 // Create a PLT entry for a global symbol.
1501
1502 void
1503 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
1504 {
1505 if (gsym->has_plt_offset())
1506 return;
1507 if (this->plt_ == NULL)
1508 this->make_plt_section(symtab, layout);
1509 this->plt_->add_entry(symtab, layout, gsym);
1510 }
1511
1512 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1513
1514 void
1515 Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1516 Sized_relobj_file<32, false>* relobj,
1517 unsigned int local_sym_index)
1518 {
1519 if (relobj->local_has_plt_offset(local_sym_index))
1520 return;
1521 if (this->plt_ == NULL)
1522 this->make_plt_section(symtab, layout);
1523 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1524 relobj,
1525 local_sym_index);
1526 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1527 }
1528
1529 // Return the number of entries in the PLT.
1530
1531 unsigned int
1532 Target_i386::plt_entry_count() const
1533 {
1534 if (this->plt_ == NULL)
1535 return 0;
1536 return this->plt_->entry_count();
1537 }
1538
1539 // Return the offset of the first non-reserved PLT entry.
1540
1541 unsigned int
1542 Target_i386::first_plt_entry_offset() const
1543 {
1544 return this->plt_->first_plt_entry_offset();
1545 }
1546
1547 // Return the size of each PLT entry.
1548
1549 unsigned int
1550 Target_i386::plt_entry_size() const
1551 {
1552 return this->plt_->get_plt_entry_size();
1553 }
1554
1555 // Get the section to use for TLS_DESC relocations.
1556
1557 Target_i386::Reloc_section*
1558 Target_i386::rel_tls_desc_section(Layout* layout) const
1559 {
1560 return this->plt_section()->rel_tls_desc(layout);
1561 }
1562
1563 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1564
1565 void
1566 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1567 {
1568 if (this->tls_base_symbol_defined_)
1569 return;
1570
1571 Output_segment* tls_segment = layout->tls_segment();
1572 if (tls_segment != NULL)
1573 {
1574 bool is_exec = parameters->options().output_is_executable();
1575 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1576 Symbol_table::PREDEFINED,
1577 tls_segment, 0, 0,
1578 elfcpp::STT_TLS,
1579 elfcpp::STB_LOCAL,
1580 elfcpp::STV_HIDDEN, 0,
1581 (is_exec
1582 ? Symbol::SEGMENT_END
1583 : Symbol::SEGMENT_START),
1584 true);
1585 }
1586 this->tls_base_symbol_defined_ = true;
1587 }
1588
1589 // Create a GOT entry for the TLS module index.
1590
1591 unsigned int
1592 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1593 Sized_relobj_file<32, false>* object)
1594 {
1595 if (this->got_mod_index_offset_ == -1U)
1596 {
1597 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1598 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1599 Output_data_got<32, false>* got = this->got_section(symtab, layout);
1600 unsigned int got_offset = got->add_constant(0);
1601 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
1602 got_offset);
1603 got->add_constant(0);
1604 this->got_mod_index_offset_ = got_offset;
1605 }
1606 return this->got_mod_index_offset_;
1607 }
1608
1609 // Optimize the TLS relocation type based on what we know about the
1610 // symbol. IS_FINAL is true if the final address of this symbol is
1611 // known at link time.
1612
1613 tls::Tls_optimization
1614 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
1615 {
1616 // If we are generating a shared library, then we can't do anything
1617 // in the linker.
1618 if (parameters->options().shared())
1619 return tls::TLSOPT_NONE;
1620
1621 switch (r_type)
1622 {
1623 case elfcpp::R_386_TLS_GD:
1624 case elfcpp::R_386_TLS_GOTDESC:
1625 case elfcpp::R_386_TLS_DESC_CALL:
1626 // These are General-Dynamic which permits fully general TLS
1627 // access. Since we know that we are generating an executable,
1628 // we can convert this to Initial-Exec. If we also know that
1629 // this is a local symbol, we can further switch to Local-Exec.
1630 if (is_final)
1631 return tls::TLSOPT_TO_LE;
1632 return tls::TLSOPT_TO_IE;
1633
1634 case elfcpp::R_386_TLS_LDM:
1635 // This is Local-Dynamic, which refers to a local symbol in the
1636 // dynamic TLS block. Since we know that we generating an
1637 // executable, we can switch to Local-Exec.
1638 return tls::TLSOPT_TO_LE;
1639
1640 case elfcpp::R_386_TLS_LDO_32:
1641 // Another type of Local-Dynamic relocation.
1642 return tls::TLSOPT_TO_LE;
1643
1644 case elfcpp::R_386_TLS_IE:
1645 case elfcpp::R_386_TLS_GOTIE:
1646 case elfcpp::R_386_TLS_IE_32:
1647 // These are Initial-Exec relocs which get the thread offset
1648 // from the GOT. If we know that we are linking against the
1649 // local symbol, we can switch to Local-Exec, which links the
1650 // thread offset into the instruction.
1651 if (is_final)
1652 return tls::TLSOPT_TO_LE;
1653 return tls::TLSOPT_NONE;
1654
1655 case elfcpp::R_386_TLS_LE:
1656 case elfcpp::R_386_TLS_LE_32:
1657 // When we already have Local-Exec, there is nothing further we
1658 // can do.
1659 return tls::TLSOPT_NONE;
1660
1661 default:
1662 gold_unreachable();
1663 }
1664 }
1665
1666 // Get the Reference_flags for a particular relocation.
1667
1668 int
1669 Target_i386::Scan::get_reference_flags(unsigned int r_type)
1670 {
1671 switch (r_type)
1672 {
1673 case elfcpp::R_386_NONE:
1674 case elfcpp::R_386_GNU_VTINHERIT:
1675 case elfcpp::R_386_GNU_VTENTRY:
1676 case elfcpp::R_386_GOTPC:
1677 // No symbol reference.
1678 return 0;
1679
1680 case elfcpp::R_386_32:
1681 case elfcpp::R_386_16:
1682 case elfcpp::R_386_8:
1683 return Symbol::ABSOLUTE_REF;
1684
1685 case elfcpp::R_386_PC32:
1686 case elfcpp::R_386_PC16:
1687 case elfcpp::R_386_PC8:
1688 case elfcpp::R_386_GOTOFF:
1689 return Symbol::RELATIVE_REF;
1690
1691 case elfcpp::R_386_PLT32:
1692 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1693
1694 case elfcpp::R_386_GOT32:
1695 case elfcpp::R_386_GOT32X:
1696 // Absolute in GOT.
1697 return Symbol::ABSOLUTE_REF;
1698
1699 case elfcpp::R_386_TLS_GD: // Global-dynamic
1700 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1701 case elfcpp::R_386_TLS_DESC_CALL:
1702 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1703 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1704 case elfcpp::R_386_TLS_IE: // Initial-exec
1705 case elfcpp::R_386_TLS_IE_32:
1706 case elfcpp::R_386_TLS_GOTIE:
1707 case elfcpp::R_386_TLS_LE: // Local-exec
1708 case elfcpp::R_386_TLS_LE_32:
1709 return Symbol::TLS_REF;
1710
1711 case elfcpp::R_386_COPY:
1712 case elfcpp::R_386_GLOB_DAT:
1713 case elfcpp::R_386_JUMP_SLOT:
1714 case elfcpp::R_386_RELATIVE:
1715 case elfcpp::R_386_IRELATIVE:
1716 case elfcpp::R_386_TLS_TPOFF:
1717 case elfcpp::R_386_TLS_DTPMOD32:
1718 case elfcpp::R_386_TLS_DTPOFF32:
1719 case elfcpp::R_386_TLS_TPOFF32:
1720 case elfcpp::R_386_TLS_DESC:
1721 case elfcpp::R_386_32PLT:
1722 case elfcpp::R_386_TLS_GD_32:
1723 case elfcpp::R_386_TLS_GD_PUSH:
1724 case elfcpp::R_386_TLS_GD_CALL:
1725 case elfcpp::R_386_TLS_GD_POP:
1726 case elfcpp::R_386_TLS_LDM_32:
1727 case elfcpp::R_386_TLS_LDM_PUSH:
1728 case elfcpp::R_386_TLS_LDM_CALL:
1729 case elfcpp::R_386_TLS_LDM_POP:
1730 case elfcpp::R_386_USED_BY_INTEL_200:
1731 default:
1732 // Not expected. We will give an error later.
1733 return 0;
1734 }
1735 }
1736
1737 // Report an unsupported relocation against a local symbol.
1738
1739 void
1740 Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
1741 unsigned int r_type)
1742 {
1743 gold_error(_("%s: unsupported reloc %u against local symbol"),
1744 object->name().c_str(), r_type);
1745 }
1746
1747 // Return whether we need to make a PLT entry for a relocation of a
1748 // given type against a STT_GNU_IFUNC symbol.
1749
1750 bool
1751 Target_i386::Scan::reloc_needs_plt_for_ifunc(
1752 Sized_relobj_file<32, false>* object,
1753 unsigned int r_type)
1754 {
1755 int flags = Scan::get_reference_flags(r_type);
1756 if (flags & Symbol::TLS_REF)
1757 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1758 object->name().c_str(), r_type);
1759 return flags != 0;
1760 }
1761
1762 // Scan a relocation for a local symbol.
1763
1764 inline void
1765 Target_i386::Scan::local(Symbol_table* symtab,
1766 Layout* layout,
1767 Target_i386* target,
1768 Sized_relobj_file<32, false>* object,
1769 unsigned int data_shndx,
1770 Output_section* output_section,
1771 const elfcpp::Rel<32, false>& reloc,
1772 unsigned int r_type,
1773 const elfcpp::Sym<32, false>& lsym,
1774 bool is_discarded)
1775 {
1776 if (is_discarded)
1777 return;
1778
1779 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1780 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1781 && this->reloc_needs_plt_for_ifunc(object, r_type))
1782 {
1783 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1784 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1785 }
1786
1787 switch (r_type)
1788 {
1789 case elfcpp::R_386_NONE:
1790 case elfcpp::R_386_GNU_VTINHERIT:
1791 case elfcpp::R_386_GNU_VTENTRY:
1792 break;
1793
1794 case elfcpp::R_386_32:
1795 // If building a shared library (or a position-independent
1796 // executable), we need to create a dynamic relocation for
1797 // this location. The relocation applied at link time will
1798 // apply the link-time value, so we flag the location with
1799 // an R_386_RELATIVE relocation so the dynamic loader can
1800 // relocate it easily.
1801 if (parameters->options().output_is_position_independent())
1802 {
1803 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1804 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1805 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1806 output_section, data_shndx,
1807 reloc.get_r_offset());
1808 }
1809 break;
1810
1811 case elfcpp::R_386_16:
1812 case elfcpp::R_386_8:
1813 // If building a shared library (or a position-independent
1814 // executable), we need to create a dynamic relocation for
1815 // this location. Because the addend needs to remain in the
1816 // data section, we need to be careful not to apply this
1817 // relocation statically.
1818 if (parameters->options().output_is_position_independent())
1819 {
1820 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1821 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1822 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1823 rel_dyn->add_local(object, r_sym, r_type, output_section,
1824 data_shndx, reloc.get_r_offset());
1825 else
1826 {
1827 gold_assert(lsym.get_st_value() == 0);
1828 unsigned int shndx = lsym.get_st_shndx();
1829 bool is_ordinary;
1830 shndx = object->adjust_sym_shndx(r_sym, shndx,
1831 &is_ordinary);
1832 if (!is_ordinary)
1833 object->error(_("section symbol %u has bad shndx %u"),
1834 r_sym, shndx);
1835 else
1836 rel_dyn->add_local_section(object, shndx,
1837 r_type, output_section,
1838 data_shndx, reloc.get_r_offset());
1839 }
1840 }
1841 break;
1842
1843 case elfcpp::R_386_PC32:
1844 case elfcpp::R_386_PC16:
1845 case elfcpp::R_386_PC8:
1846 break;
1847
1848 case elfcpp::R_386_PLT32:
1849 // Since we know this is a local symbol, we can handle this as a
1850 // PC32 reloc.
1851 break;
1852
1853 case elfcpp::R_386_GOTOFF:
1854 case elfcpp::R_386_GOTPC:
1855 // We need a GOT section.
1856 target->got_section(symtab, layout);
1857 break;
1858
1859 case elfcpp::R_386_GOT32:
1860 case elfcpp::R_386_GOT32X:
1861 {
1862 // We need GOT section.
1863 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1864
1865 // If the relocation symbol isn't IFUNC,
1866 // and is local, then we will convert
1867 // mov foo@GOT(%reg), %reg
1868 // to
1869 // lea foo@GOTOFF(%reg), %reg
1870 // in Relocate::relocate.
1871 if (reloc.get_r_offset() >= 2
1872 && lsym.get_st_type() != elfcpp::STT_GNU_IFUNC)
1873 {
1874 section_size_type stype;
1875 const unsigned char* view = object->section_contents(data_shndx,
1876 &stype, true);
1877 if (view[reloc.get_r_offset() - 2] == 0x8b)
1878 break;
1879 }
1880
1881 // Otherwise, the symbol requires a GOT entry.
1882 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1883
1884 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1885 // lets function pointers compare correctly with shared
1886 // libraries. Otherwise we would need an IRELATIVE reloc.
1887 bool is_new;
1888 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1889 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1890 else
1891 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1892 if (is_new)
1893 {
1894 // If we are generating a shared object, we need to add a
1895 // dynamic RELATIVE relocation for this symbol's GOT entry.
1896 if (parameters->options().output_is_position_independent())
1897 {
1898 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1899 unsigned int got_offset =
1900 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1901 rel_dyn->add_local_relative(object, r_sym,
1902 elfcpp::R_386_RELATIVE,
1903 got, got_offset);
1904 }
1905 }
1906 }
1907 break;
1908
1909 // These are relocations which should only be seen by the
1910 // dynamic linker, and should never be seen here.
1911 case elfcpp::R_386_COPY:
1912 case elfcpp::R_386_GLOB_DAT:
1913 case elfcpp::R_386_JUMP_SLOT:
1914 case elfcpp::R_386_RELATIVE:
1915 case elfcpp::R_386_IRELATIVE:
1916 case elfcpp::R_386_TLS_TPOFF:
1917 case elfcpp::R_386_TLS_DTPMOD32:
1918 case elfcpp::R_386_TLS_DTPOFF32:
1919 case elfcpp::R_386_TLS_TPOFF32:
1920 case elfcpp::R_386_TLS_DESC:
1921 gold_error(_("%s: unexpected reloc %u in object file"),
1922 object->name().c_str(), r_type);
1923 break;
1924
1925 // These are initial TLS relocs, which are expected when
1926 // linking.
1927 case elfcpp::R_386_TLS_GD: // Global-dynamic
1928 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1929 case elfcpp::R_386_TLS_DESC_CALL:
1930 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1931 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1932 case elfcpp::R_386_TLS_IE: // Initial-exec
1933 case elfcpp::R_386_TLS_IE_32:
1934 case elfcpp::R_386_TLS_GOTIE:
1935 case elfcpp::R_386_TLS_LE: // Local-exec
1936 case elfcpp::R_386_TLS_LE_32:
1937 {
1938 bool output_is_shared = parameters->options().shared();
1939 const tls::Tls_optimization optimized_type
1940 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1941 switch (r_type)
1942 {
1943 case elfcpp::R_386_TLS_GD: // Global-dynamic
1944 if (optimized_type == tls::TLSOPT_NONE)
1945 {
1946 // Create a pair of GOT entries for the module index and
1947 // dtv-relative offset.
1948 Output_data_got<32, false>* got
1949 = target->got_section(symtab, layout);
1950 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1951 unsigned int shndx = lsym.get_st_shndx();
1952 bool is_ordinary;
1953 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1954 if (!is_ordinary)
1955 object->error(_("local symbol %u has bad shndx %u"),
1956 r_sym, shndx);
1957 else
1958 got->add_local_pair_with_rel(object, r_sym, shndx,
1959 GOT_TYPE_TLS_PAIR,
1960 target->rel_dyn_section(layout),
1961 elfcpp::R_386_TLS_DTPMOD32);
1962 }
1963 else if (optimized_type != tls::TLSOPT_TO_LE)
1964 unsupported_reloc_local(object, r_type);
1965 break;
1966
1967 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1968 target->define_tls_base_symbol(symtab, layout);
1969 if (optimized_type == tls::TLSOPT_NONE)
1970 {
1971 // Create a double GOT entry with an R_386_TLS_DESC
1972 // reloc. The R_386_TLS_DESC reloc is resolved
1973 // lazily, so the GOT entry needs to be in an area in
1974 // .got.plt, not .got. Call got_section to make sure
1975 // the section has been created.
1976 target->got_section(symtab, layout);
1977 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1978 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1979 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1980 {
1981 unsigned int got_offset = got->add_constant(0);
1982 // The local symbol value is stored in the second
1983 // GOT entry.
1984 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1985 // That set the GOT offset of the local symbol to
1986 // point to the second entry, but we want it to
1987 // point to the first.
1988 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1989 got_offset);
1990 Reloc_section* rt = target->rel_tls_desc_section(layout);
1991 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1992 }
1993 }
1994 else if (optimized_type != tls::TLSOPT_TO_LE)
1995 unsupported_reloc_local(object, r_type);
1996 break;
1997
1998 case elfcpp::R_386_TLS_DESC_CALL:
1999 break;
2000
2001 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2002 if (optimized_type == tls::TLSOPT_NONE)
2003 {
2004 // Create a GOT entry for the module index.
2005 target->got_mod_index_entry(symtab, layout, object);
2006 }
2007 else if (optimized_type != tls::TLSOPT_TO_LE)
2008 unsupported_reloc_local(object, r_type);
2009 break;
2010
2011 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2012 break;
2013
2014 case elfcpp::R_386_TLS_IE: // Initial-exec
2015 case elfcpp::R_386_TLS_IE_32:
2016 case elfcpp::R_386_TLS_GOTIE:
2017 layout->set_has_static_tls();
2018 if (optimized_type == tls::TLSOPT_NONE)
2019 {
2020 // For the R_386_TLS_IE relocation, we need to create a
2021 // dynamic relocation when building a shared library.
2022 if (r_type == elfcpp::R_386_TLS_IE
2023 && parameters->options().shared())
2024 {
2025 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2026 unsigned int r_sym
2027 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2028 rel_dyn->add_local_relative(object, r_sym,
2029 elfcpp::R_386_RELATIVE,
2030 output_section, data_shndx,
2031 reloc.get_r_offset());
2032 }
2033 // Create a GOT entry for the tp-relative offset.
2034 Output_data_got<32, false>* got
2035 = target->got_section(symtab, layout);
2036 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2037 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2038 ? elfcpp::R_386_TLS_TPOFF32
2039 : elfcpp::R_386_TLS_TPOFF);
2040 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2041 ? GOT_TYPE_TLS_OFFSET
2042 : GOT_TYPE_TLS_NOFFSET);
2043 got->add_local_with_rel(object, r_sym, got_type,
2044 target->rel_dyn_section(layout),
2045 dyn_r_type);
2046 }
2047 else if (optimized_type != tls::TLSOPT_TO_LE)
2048 unsupported_reloc_local(object, r_type);
2049 break;
2050
2051 case elfcpp::R_386_TLS_LE: // Local-exec
2052 case elfcpp::R_386_TLS_LE_32:
2053 layout->set_has_static_tls();
2054 if (output_is_shared)
2055 {
2056 // We need to create a dynamic relocation.
2057 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2058 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2059 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2060 ? elfcpp::R_386_TLS_TPOFF32
2061 : elfcpp::R_386_TLS_TPOFF);
2062 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2063 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
2064 data_shndx, reloc.get_r_offset());
2065 }
2066 break;
2067
2068 default:
2069 gold_unreachable();
2070 }
2071 }
2072 break;
2073
2074 case elfcpp::R_386_32PLT:
2075 case elfcpp::R_386_TLS_GD_32:
2076 case elfcpp::R_386_TLS_GD_PUSH:
2077 case elfcpp::R_386_TLS_GD_CALL:
2078 case elfcpp::R_386_TLS_GD_POP:
2079 case elfcpp::R_386_TLS_LDM_32:
2080 case elfcpp::R_386_TLS_LDM_PUSH:
2081 case elfcpp::R_386_TLS_LDM_CALL:
2082 case elfcpp::R_386_TLS_LDM_POP:
2083 case elfcpp::R_386_USED_BY_INTEL_200:
2084 default:
2085 unsupported_reloc_local(object, r_type);
2086 break;
2087 }
2088 }
2089
2090 // Report an unsupported relocation against a global symbol.
2091
2092 void
2093 Target_i386::Scan::unsupported_reloc_global(
2094 Sized_relobj_file<32, false>* object,
2095 unsigned int r_type,
2096 Symbol* gsym)
2097 {
2098 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2099 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2100 }
2101
2102 inline bool
2103 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
2104 {
2105 switch (r_type)
2106 {
2107 case elfcpp::R_386_32:
2108 case elfcpp::R_386_16:
2109 case elfcpp::R_386_8:
2110 case elfcpp::R_386_GOTOFF:
2111 case elfcpp::R_386_GOT32:
2112 case elfcpp::R_386_GOT32X:
2113 {
2114 return true;
2115 }
2116 default:
2117 return false;
2118 }
2119 return false;
2120 }
2121
2122 inline bool
2123 Target_i386::Scan::local_reloc_may_be_function_pointer(
2124 Symbol_table* ,
2125 Layout* ,
2126 Target_i386* ,
2127 Sized_relobj_file<32, false>* ,
2128 unsigned int ,
2129 Output_section* ,
2130 const elfcpp::Rel<32, false>& ,
2131 unsigned int r_type,
2132 const elfcpp::Sym<32, false>&)
2133 {
2134 return possible_function_pointer_reloc(r_type);
2135 }
2136
2137 inline bool
2138 Target_i386::Scan::global_reloc_may_be_function_pointer(
2139 Symbol_table* ,
2140 Layout* ,
2141 Target_i386* ,
2142 Sized_relobj_file<32, false>* ,
2143 unsigned int ,
2144 Output_section* ,
2145 const elfcpp::Rel<32, false>& ,
2146 unsigned int r_type,
2147 Symbol*)
2148 {
2149 return possible_function_pointer_reloc(r_type);
2150 }
2151
2152 // Scan a relocation for a global symbol.
2153
2154 inline void
2155 Target_i386::Scan::global(Symbol_table* symtab,
2156 Layout* layout,
2157 Target_i386* target,
2158 Sized_relobj_file<32, false>* object,
2159 unsigned int data_shndx,
2160 Output_section* output_section,
2161 const elfcpp::Rel<32, false>& reloc,
2162 unsigned int r_type,
2163 Symbol* gsym)
2164 {
2165 // A STT_GNU_IFUNC symbol may require a PLT entry.
2166 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2167 && this->reloc_needs_plt_for_ifunc(object, r_type))
2168 target->make_plt_entry(symtab, layout, gsym);
2169
2170 switch (r_type)
2171 {
2172 case elfcpp::R_386_NONE:
2173 case elfcpp::R_386_GNU_VTINHERIT:
2174 case elfcpp::R_386_GNU_VTENTRY:
2175 break;
2176
2177 case elfcpp::R_386_32:
2178 case elfcpp::R_386_16:
2179 case elfcpp::R_386_8:
2180 {
2181 // Make a PLT entry if necessary.
2182 if (gsym->needs_plt_entry())
2183 {
2184 target->make_plt_entry(symtab, layout, gsym);
2185 // Since this is not a PC-relative relocation, we may be
2186 // taking the address of a function. In that case we need to
2187 // set the entry in the dynamic symbol table to the address of
2188 // the PLT entry.
2189 if (gsym->is_from_dynobj() && !parameters->options().shared())
2190 gsym->set_needs_dynsym_value();
2191 }
2192 // Make a dynamic relocation if necessary.
2193 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2194 {
2195 if (!parameters->options().output_is_position_independent()
2196 && gsym->may_need_copy_reloc())
2197 {
2198 target->copy_reloc(symtab, layout, object,
2199 data_shndx, output_section, gsym, reloc);
2200 }
2201 else if (r_type == elfcpp::R_386_32
2202 && gsym->type() == elfcpp::STT_GNU_IFUNC
2203 && gsym->can_use_relative_reloc(false)
2204 && !gsym->is_from_dynobj()
2205 && !gsym->is_undefined()
2206 && !gsym->is_preemptible())
2207 {
2208 // Use an IRELATIVE reloc for a locally defined
2209 // STT_GNU_IFUNC symbol. This makes a function
2210 // address in a PIE executable match the address in a
2211 // shared library that it links against.
2212 Reloc_section* rel_dyn = target->rel_irelative_section(layout);
2213 rel_dyn->add_symbolless_global_addend(gsym,
2214 elfcpp::R_386_IRELATIVE,
2215 output_section,
2216 object, data_shndx,
2217 reloc.get_r_offset());
2218 }
2219 else if (r_type == elfcpp::R_386_32
2220 && gsym->can_use_relative_reloc(false))
2221 {
2222 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2223 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2224 output_section, object,
2225 data_shndx, reloc.get_r_offset());
2226 }
2227 else
2228 {
2229 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2230 rel_dyn->add_global(gsym, r_type, output_section, object,
2231 data_shndx, reloc.get_r_offset());
2232 }
2233 }
2234 }
2235 break;
2236
2237 case elfcpp::R_386_PC32:
2238 case elfcpp::R_386_PC16:
2239 case elfcpp::R_386_PC8:
2240 {
2241 // Make a PLT entry if necessary.
2242 if (gsym->needs_plt_entry())
2243 {
2244 // These relocations are used for function calls only in
2245 // non-PIC code. For a 32-bit relocation in a shared library,
2246 // we'll need a text relocation anyway, so we can skip the
2247 // PLT entry and let the dynamic linker bind the call directly
2248 // to the target. For smaller relocations, we should use a
2249 // PLT entry to ensure that the call can reach.
2250 if (!parameters->options().shared()
2251 || r_type != elfcpp::R_386_PC32)
2252 target->make_plt_entry(symtab, layout, gsym);
2253 }
2254 // Make a dynamic relocation if necessary.
2255 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2256 {
2257 if (parameters->options().output_is_executable()
2258 && gsym->may_need_copy_reloc())
2259 {
2260 target->copy_reloc(symtab, layout, object,
2261 data_shndx, output_section, gsym, reloc);
2262 }
2263 else
2264 {
2265 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2266 rel_dyn->add_global(gsym, r_type, output_section, object,
2267 data_shndx, reloc.get_r_offset());
2268 }
2269 }
2270 }
2271 break;
2272
2273 case elfcpp::R_386_GOT32:
2274 case elfcpp::R_386_GOT32X:
2275 {
2276 // The symbol requires a GOT section.
2277 Output_data_got<32, false>* got = target->got_section(symtab, layout);
2278
2279 // If we convert this from
2280 // mov foo@GOT(%reg), %reg
2281 // to
2282 // lea foo@GOTOFF(%reg), %reg
2283 // in Relocate::relocate, then there is nothing to do here.
2284 if (reloc.get_r_offset() >= 2
2285 && Target_i386::can_convert_mov_to_lea(gsym))
2286 {
2287 section_size_type stype;
2288 const unsigned char* view = object->section_contents(data_shndx,
2289 &stype, true);
2290 if (view[reloc.get_r_offset() - 2] == 0x8b)
2291 break;
2292 }
2293
2294 if (gsym->final_value_is_known())
2295 {
2296 // For a STT_GNU_IFUNC symbol we want the PLT address.
2297 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2298 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2299 else
2300 got->add_global(gsym, GOT_TYPE_STANDARD);
2301 }
2302 else
2303 {
2304 // If this symbol is not fully resolved, we need to add a
2305 // GOT entry with a dynamic relocation.
2306 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2307
2308 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2309 //
2310 // 1) The symbol may be defined in some other module.
2311 //
2312 // 2) We are building a shared library and this is a
2313 // protected symbol; using GLOB_DAT means that the dynamic
2314 // linker can use the address of the PLT in the main
2315 // executable when appropriate so that function address
2316 // comparisons work.
2317 //
2318 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2319 // code, again so that function address comparisons work.
2320 if (gsym->is_from_dynobj()
2321 || gsym->is_undefined()
2322 || gsym->is_preemptible()
2323 || (gsym->visibility() == elfcpp::STV_PROTECTED
2324 && parameters->options().shared())
2325 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2326 && parameters->options().output_is_position_independent()))
2327 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
2328 rel_dyn, elfcpp::R_386_GLOB_DAT);
2329 else
2330 {
2331 // For a STT_GNU_IFUNC symbol we want to write the PLT
2332 // offset into the GOT, so that function pointer
2333 // comparisons work correctly.
2334 bool is_new;
2335 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2336 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2337 else
2338 {
2339 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2340 // Tell the dynamic linker to use the PLT address
2341 // when resolving relocations.
2342 if (gsym->is_from_dynobj()
2343 && !parameters->options().shared())
2344 gsym->set_needs_dynsym_value();
2345 }
2346 if (is_new)
2347 {
2348 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2349 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2350 got, got_off);
2351 }
2352 }
2353 }
2354 }
2355 break;
2356
2357 case elfcpp::R_386_PLT32:
2358 // If the symbol is fully resolved, this is just a PC32 reloc.
2359 // Otherwise we need a PLT entry.
2360 if (gsym->final_value_is_known())
2361 break;
2362 // If building a shared library, we can also skip the PLT entry
2363 // if the symbol is defined in the output file and is protected
2364 // or hidden.
2365 if (gsym->is_defined()
2366 && !gsym->is_from_dynobj()
2367 && !gsym->is_preemptible())
2368 break;
2369 target->make_plt_entry(symtab, layout, gsym);
2370 break;
2371
2372 case elfcpp::R_386_GOTOFF:
2373 case elfcpp::R_386_GOTPC:
2374 // We need a GOT section.
2375 target->got_section(symtab, layout);
2376 break;
2377
2378 // These are relocations which should only be seen by the
2379 // dynamic linker, and should never be seen here.
2380 case elfcpp::R_386_COPY:
2381 case elfcpp::R_386_GLOB_DAT:
2382 case elfcpp::R_386_JUMP_SLOT:
2383 case elfcpp::R_386_RELATIVE:
2384 case elfcpp::R_386_IRELATIVE:
2385 case elfcpp::R_386_TLS_TPOFF:
2386 case elfcpp::R_386_TLS_DTPMOD32:
2387 case elfcpp::R_386_TLS_DTPOFF32:
2388 case elfcpp::R_386_TLS_TPOFF32:
2389 case elfcpp::R_386_TLS_DESC:
2390 gold_error(_("%s: unexpected reloc %u in object file"),
2391 object->name().c_str(), r_type);
2392 break;
2393
2394 // These are initial tls relocs, which are expected when
2395 // linking.
2396 case elfcpp::R_386_TLS_GD: // Global-dynamic
2397 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2398 case elfcpp::R_386_TLS_DESC_CALL:
2399 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2400 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2401 case elfcpp::R_386_TLS_IE: // Initial-exec
2402 case elfcpp::R_386_TLS_IE_32:
2403 case elfcpp::R_386_TLS_GOTIE:
2404 case elfcpp::R_386_TLS_LE: // Local-exec
2405 case elfcpp::R_386_TLS_LE_32:
2406 {
2407 const bool is_final = gsym->final_value_is_known();
2408 const tls::Tls_optimization optimized_type
2409 = Target_i386::optimize_tls_reloc(is_final, r_type);
2410 switch (r_type)
2411 {
2412 case elfcpp::R_386_TLS_GD: // Global-dynamic
2413 if (optimized_type == tls::TLSOPT_NONE)
2414 {
2415 // Create a pair of GOT entries for the module index and
2416 // dtv-relative offset.
2417 Output_data_got<32, false>* got
2418 = target->got_section(symtab, layout);
2419 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2420 target->rel_dyn_section(layout),
2421 elfcpp::R_386_TLS_DTPMOD32,
2422 elfcpp::R_386_TLS_DTPOFF32);
2423 }
2424 else if (optimized_type == tls::TLSOPT_TO_IE)
2425 {
2426 // Create a GOT entry for the tp-relative offset.
2427 Output_data_got<32, false>* got
2428 = target->got_section(symtab, layout);
2429 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2430 target->rel_dyn_section(layout),
2431 elfcpp::R_386_TLS_TPOFF);
2432 }
2433 else if (optimized_type != tls::TLSOPT_TO_LE)
2434 unsupported_reloc_global(object, r_type, gsym);
2435 break;
2436
2437 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
2438 target->define_tls_base_symbol(symtab, layout);
2439 if (optimized_type == tls::TLSOPT_NONE)
2440 {
2441 // Create a double GOT entry with an R_386_TLS_DESC
2442 // reloc. The R_386_TLS_DESC reloc is resolved
2443 // lazily, so the GOT entry needs to be in an area in
2444 // .got.plt, not .got. Call got_section to make sure
2445 // the section has been created.
2446 target->got_section(symtab, layout);
2447 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2448 Reloc_section* rt = target->rel_tls_desc_section(layout);
2449 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2450 elfcpp::R_386_TLS_DESC, 0);
2451 }
2452 else if (optimized_type == tls::TLSOPT_TO_IE)
2453 {
2454 // Create a GOT entry for the tp-relative offset.
2455 Output_data_got<32, false>* got
2456 = target->got_section(symtab, layout);
2457 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2458 target->rel_dyn_section(layout),
2459 elfcpp::R_386_TLS_TPOFF);
2460 }
2461 else if (optimized_type != tls::TLSOPT_TO_LE)
2462 unsupported_reloc_global(object, r_type, gsym);
2463 break;
2464
2465 case elfcpp::R_386_TLS_DESC_CALL:
2466 break;
2467
2468 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2469 if (optimized_type == tls::TLSOPT_NONE)
2470 {
2471 // Create a GOT entry for the module index.
2472 target->got_mod_index_entry(symtab, layout, object);
2473 }
2474 else if (optimized_type != tls::TLSOPT_TO_LE)
2475 unsupported_reloc_global(object, r_type, gsym);
2476 break;
2477
2478 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2479 break;
2480
2481 case elfcpp::R_386_TLS_IE: // Initial-exec
2482 case elfcpp::R_386_TLS_IE_32:
2483 case elfcpp::R_386_TLS_GOTIE:
2484 layout->set_has_static_tls();
2485 if (optimized_type == tls::TLSOPT_NONE)
2486 {
2487 // For the R_386_TLS_IE relocation, we need to create a
2488 // dynamic relocation when building a shared library.
2489 if (r_type == elfcpp::R_386_TLS_IE
2490 && parameters->options().shared())
2491 {
2492 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2493 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2494 output_section, object,
2495 data_shndx,
2496 reloc.get_r_offset());
2497 }
2498 // Create a GOT entry for the tp-relative offset.
2499 Output_data_got<32, false>* got
2500 = target->got_section(symtab, layout);
2501 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2502 ? elfcpp::R_386_TLS_TPOFF32
2503 : elfcpp::R_386_TLS_TPOFF);
2504 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2505 ? GOT_TYPE_TLS_OFFSET
2506 : GOT_TYPE_TLS_NOFFSET);
2507 got->add_global_with_rel(gsym, got_type,
2508 target->rel_dyn_section(layout),
2509 dyn_r_type);
2510 }
2511 else if (optimized_type != tls::TLSOPT_TO_LE)
2512 unsupported_reloc_global(object, r_type, gsym);
2513 break;
2514
2515 case elfcpp::R_386_TLS_LE: // Local-exec
2516 case elfcpp::R_386_TLS_LE_32:
2517 layout->set_has_static_tls();
2518 if (parameters->options().shared())
2519 {
2520 // We need to create a dynamic relocation.
2521 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2522 ? elfcpp::R_386_TLS_TPOFF32
2523 : elfcpp::R_386_TLS_TPOFF);
2524 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2525 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
2526 data_shndx, reloc.get_r_offset());
2527 }
2528 break;
2529
2530 default:
2531 gold_unreachable();
2532 }
2533 }
2534 break;
2535
2536 case elfcpp::R_386_32PLT:
2537 case elfcpp::R_386_TLS_GD_32:
2538 case elfcpp::R_386_TLS_GD_PUSH:
2539 case elfcpp::R_386_TLS_GD_CALL:
2540 case elfcpp::R_386_TLS_GD_POP:
2541 case elfcpp::R_386_TLS_LDM_32:
2542 case elfcpp::R_386_TLS_LDM_PUSH:
2543 case elfcpp::R_386_TLS_LDM_CALL:
2544 case elfcpp::R_386_TLS_LDM_POP:
2545 case elfcpp::R_386_USED_BY_INTEL_200:
2546 default:
2547 unsupported_reloc_global(object, r_type, gsym);
2548 break;
2549 }
2550 }
2551
2552 // Process relocations for gc.
2553
2554 void
2555 Target_i386::gc_process_relocs(Symbol_table* symtab,
2556 Layout* layout,
2557 Sized_relobj_file<32, false>* object,
2558 unsigned int data_shndx,
2559 unsigned int,
2560 const unsigned char* prelocs,
2561 size_t reloc_count,
2562 Output_section* output_section,
2563 bool needs_special_offset_handling,
2564 size_t local_symbol_count,
2565 const unsigned char* plocal_symbols)
2566 {
2567 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2568 Target_i386::Scan,
2569 Target_i386::Relocatable_size_for_reloc>(
2570 symtab,
2571 layout,
2572 this,
2573 object,
2574 data_shndx,
2575 prelocs,
2576 reloc_count,
2577 output_section,
2578 needs_special_offset_handling,
2579 local_symbol_count,
2580 plocal_symbols);
2581 }
2582
2583 // Scan relocations for a section.
2584
2585 void
2586 Target_i386::scan_relocs(Symbol_table* symtab,
2587 Layout* layout,
2588 Sized_relobj_file<32, false>* object,
2589 unsigned int data_shndx,
2590 unsigned int sh_type,
2591 const unsigned char* prelocs,
2592 size_t reloc_count,
2593 Output_section* output_section,
2594 bool needs_special_offset_handling,
2595 size_t local_symbol_count,
2596 const unsigned char* plocal_symbols)
2597 {
2598 if (sh_type == elfcpp::SHT_RELA)
2599 {
2600 gold_error(_("%s: unsupported RELA reloc section"),
2601 object->name().c_str());
2602 return;
2603 }
2604
2605 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2606 Target_i386::Scan>(
2607 symtab,
2608 layout,
2609 this,
2610 object,
2611 data_shndx,
2612 prelocs,
2613 reloc_count,
2614 output_section,
2615 needs_special_offset_handling,
2616 local_symbol_count,
2617 plocal_symbols);
2618 }
2619
2620 // Finalize the sections.
2621
2622 void
2623 Target_i386::do_finalize_sections(
2624 Layout* layout,
2625 const Input_objects*,
2626 Symbol_table* symtab)
2627 {
2628 const Reloc_section* rel_plt = (this->plt_ == NULL
2629 ? NULL
2630 : this->plt_->rel_plt());
2631 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
2632 this->rel_dyn_, true, false);
2633
2634 // Emit any relocs we saved in an attempt to avoid generating COPY
2635 // relocs.
2636 if (this->copy_relocs_.any_saved_relocs())
2637 this->copy_relocs_.emit(this->rel_dyn_section(layout));
2638
2639 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2640 // the .got.plt section.
2641 Symbol* sym = this->global_offset_table_;
2642 if (sym != NULL)
2643 {
2644 uint32_t data_size = this->got_plt_->current_data_size();
2645 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
2646 }
2647
2648 if (parameters->doing_static_link()
2649 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2650 {
2651 // If linking statically, make sure that the __rel_iplt symbols
2652 // were defined if necessary, even if we didn't create a PLT.
2653 static const Define_symbol_in_segment syms[] =
2654 {
2655 {
2656 "__rel_iplt_start", // name
2657 elfcpp::PT_LOAD, // segment_type
2658 elfcpp::PF_W, // segment_flags_set
2659 elfcpp::PF(0), // segment_flags_clear
2660 0, // value
2661 0, // size
2662 elfcpp::STT_NOTYPE, // type
2663 elfcpp::STB_GLOBAL, // binding
2664 elfcpp::STV_HIDDEN, // visibility
2665 0, // nonvis
2666 Symbol::SEGMENT_START, // offset_from_base
2667 true // only_if_ref
2668 },
2669 {
2670 "__rel_iplt_end", // name
2671 elfcpp::PT_LOAD, // segment_type
2672 elfcpp::PF_W, // segment_flags_set
2673 elfcpp::PF(0), // segment_flags_clear
2674 0, // value
2675 0, // size
2676 elfcpp::STT_NOTYPE, // type
2677 elfcpp::STB_GLOBAL, // binding
2678 elfcpp::STV_HIDDEN, // visibility
2679 0, // nonvis
2680 Symbol::SEGMENT_START, // offset_from_base
2681 true // only_if_ref
2682 }
2683 };
2684
2685 symtab->define_symbols(layout, 2, syms,
2686 layout->script_options()->saw_sections_clause());
2687 }
2688 }
2689
2690 // Return whether a direct absolute static relocation needs to be applied.
2691 // In cases where Scan::local() or Scan::global() has created
2692 // a dynamic relocation other than R_386_RELATIVE, the addend
2693 // of the relocation is carried in the data, and we must not
2694 // apply the static relocation.
2695
2696 inline bool
2697 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
2698 unsigned int r_type,
2699 bool is_32bit,
2700 Output_section* output_section)
2701 {
2702 // If the output section is not allocated, then we didn't call
2703 // scan_relocs, we didn't create a dynamic reloc, and we must apply
2704 // the reloc here.
2705 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
2706 return true;
2707
2708 int ref_flags = Scan::get_reference_flags(r_type);
2709
2710 // For local symbols, we will have created a non-RELATIVE dynamic
2711 // relocation only if (a) the output is position independent,
2712 // (b) the relocation is absolute (not pc- or segment-relative), and
2713 // (c) the relocation is not 32 bits wide.
2714 if (gsym == NULL)
2715 return !(parameters->options().output_is_position_independent()
2716 && (ref_flags & Symbol::ABSOLUTE_REF)
2717 && !is_32bit);
2718
2719 // For global symbols, we use the same helper routines used in the
2720 // scan pass. If we did not create a dynamic relocation, or if we
2721 // created a RELATIVE dynamic relocation, we should apply the static
2722 // relocation.
2723 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
2724 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
2725 && gsym->can_use_relative_reloc(ref_flags
2726 & Symbol::FUNCTION_CALL);
2727 return !has_dyn || is_rel;
2728 }
2729
2730 // Perform a relocation.
2731
2732 inline bool
2733 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
2734 unsigned int,
2735 Target_i386* target,
2736 Output_section* output_section,
2737 size_t relnum,
2738 const unsigned char* preloc,
2739 const Sized_symbol<32>* gsym,
2740 const Symbol_value<32>* psymval,
2741 unsigned char* view,
2742 elfcpp::Elf_types<32>::Elf_Addr address,
2743 section_size_type view_size)
2744 {
2745 const elfcpp::Rel<32, false> rel(preloc);
2746 unsigned int r_type = elfcpp::elf_r_type<32>(rel.get_r_info());
2747
2748 if (this->skip_call_tls_get_addr_)
2749 {
2750 if ((r_type != elfcpp::R_386_PLT32
2751 && r_type != elfcpp::R_386_PC32)
2752 || gsym == NULL
2753 || strcmp(gsym->name(), "___tls_get_addr") != 0)
2754 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2755 _("missing expected TLS relocation"));
2756 else
2757 {
2758 this->skip_call_tls_get_addr_ = false;
2759 return false;
2760 }
2761 }
2762
2763 if (view == NULL)
2764 return true;
2765
2766 const Sized_relobj_file<32, false>* object = relinfo->object;
2767
2768 // Pick the value to use for symbols defined in shared objects.
2769 Symbol_value<32> symval;
2770 if (gsym != NULL
2771 && gsym->type() == elfcpp::STT_GNU_IFUNC
2772 && r_type == elfcpp::R_386_32
2773 && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
2774 && gsym->can_use_relative_reloc(false)
2775 && !gsym->is_from_dynobj()
2776 && !gsym->is_undefined()
2777 && !gsym->is_preemptible())
2778 {
2779 // In this case we are generating a R_386_IRELATIVE reloc. We
2780 // want to use the real value of the symbol, not the PLT offset.
2781 }
2782 else if (gsym != NULL
2783 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2784 {
2785 symval.set_output_value(target->plt_address_for_global(gsym));
2786 psymval = &symval;
2787 }
2788 else if (gsym == NULL && psymval->is_ifunc_symbol())
2789 {
2790 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2791 if (object->local_has_plt_offset(r_sym))
2792 {
2793 symval.set_output_value(target->plt_address_for_local(object, r_sym));
2794 psymval = &symval;
2795 }
2796 }
2797
2798 bool baseless;
2799
2800 switch (r_type)
2801 {
2802 case elfcpp::R_386_NONE:
2803 case elfcpp::R_386_GNU_VTINHERIT:
2804 case elfcpp::R_386_GNU_VTENTRY:
2805 break;
2806
2807 case elfcpp::R_386_32:
2808 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2809 Relocate_functions<32, false>::rel32(view, object, psymval);
2810 break;
2811
2812 case elfcpp::R_386_PC32:
2813 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2814 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2815 break;
2816
2817 case elfcpp::R_386_16:
2818 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2819 Relocate_functions<32, false>::rel16(view, object, psymval);
2820 break;
2821
2822 case elfcpp::R_386_PC16:
2823 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2824 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
2825 break;
2826
2827 case elfcpp::R_386_8:
2828 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2829 Relocate_functions<32, false>::rel8(view, object, psymval);
2830 break;
2831
2832 case elfcpp::R_386_PC8:
2833 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2834 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
2835 break;
2836
2837 case elfcpp::R_386_PLT32:
2838 gold_assert(gsym == NULL
2839 || gsym->has_plt_offset()
2840 || gsym->final_value_is_known()
2841 || (gsym->is_defined()
2842 && !gsym->is_from_dynobj()
2843 && !gsym->is_preemptible()));
2844 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2845 break;
2846
2847 case elfcpp::R_386_GOT32:
2848 case elfcpp::R_386_GOT32X:
2849 baseless = (view[-1] & 0xc7) == 0x5;
2850 // R_386_GOT32 and R_386_GOT32X don't work without base register
2851 // when generating a position-independent output file.
2852 if (baseless
2853 && parameters->options().output_is_position_independent())
2854 {
2855 if(gsym)
2856 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2857 _("unexpected reloc %u against global symbol %s without base register in object file when generating a position-independent output file"),
2858 r_type, gsym->demangled_name().c_str());
2859 else
2860 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2861 _("unexpected reloc %u against local symbol without base register in object file when generating a position-independent output file"),
2862 r_type);
2863 }
2864
2865 // Convert
2866 // mov foo@GOT(%reg), %reg
2867 // to
2868 // lea foo@GOTOFF(%reg), %reg
2869 // if possible.
2870 if (rel.get_r_offset() >= 2
2871 && view[-2] == 0x8b
2872 && ((gsym == NULL && !psymval->is_ifunc_symbol())
2873 || (gsym != NULL
2874 && Target_i386::can_convert_mov_to_lea(gsym))))
2875 {
2876 view[-2] = 0x8d;
2877 elfcpp::Elf_types<32>::Elf_Addr value;
2878 value = psymval->value(object, 0);
2879 // Don't subtract the .got.plt section address for baseless
2880 // addressing.
2881 if (!baseless)
2882 value -= target->got_plt_section()->address();
2883 Relocate_functions<32, false>::rel32(view, value);
2884 }
2885 else
2886 {
2887 // The GOT pointer points to the end of the GOT section.
2888 // We need to subtract the size of the GOT section to get
2889 // the actual offset to use in the relocation.
2890 unsigned int got_offset = 0;
2891 if (gsym != NULL)
2892 {
2893 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2894 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
2895 - target->got_size());
2896 }
2897 else
2898 {
2899 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2900 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2901 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2902 - target->got_size());
2903 }
2904 // Add the .got.plt section address for baseless addressing.
2905 if (baseless)
2906 got_offset += target->got_plt_section()->address();
2907 Relocate_functions<32, false>::rel32(view, got_offset);
2908 }
2909 break;
2910
2911 case elfcpp::R_386_GOTOFF:
2912 {
2913 elfcpp::Elf_types<32>::Elf_Addr value;
2914 value = (psymval->value(object, 0)
2915 - target->got_plt_section()->address());
2916 Relocate_functions<32, false>::rel32(view, value);
2917 }
2918 break;
2919
2920 case elfcpp::R_386_GOTPC:
2921 {
2922 elfcpp::Elf_types<32>::Elf_Addr value;
2923 value = target->got_plt_section()->address();
2924 Relocate_functions<32, false>::pcrel32(view, value, address);
2925 }
2926 break;
2927
2928 case elfcpp::R_386_COPY:
2929 case elfcpp::R_386_GLOB_DAT:
2930 case elfcpp::R_386_JUMP_SLOT:
2931 case elfcpp::R_386_RELATIVE:
2932 case elfcpp::R_386_IRELATIVE:
2933 // These are outstanding tls relocs, which are unexpected when
2934 // linking.
2935 case elfcpp::R_386_TLS_TPOFF:
2936 case elfcpp::R_386_TLS_DTPMOD32:
2937 case elfcpp::R_386_TLS_DTPOFF32:
2938 case elfcpp::R_386_TLS_TPOFF32:
2939 case elfcpp::R_386_TLS_DESC:
2940 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2941 _("unexpected reloc %u in object file"),
2942 r_type);
2943 break;
2944
2945 // These are initial tls relocs, which are expected when
2946 // linking.
2947 case elfcpp::R_386_TLS_GD: // Global-dynamic
2948 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2949 case elfcpp::R_386_TLS_DESC_CALL:
2950 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2951 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2952 case elfcpp::R_386_TLS_IE: // Initial-exec
2953 case elfcpp::R_386_TLS_IE_32:
2954 case elfcpp::R_386_TLS_GOTIE:
2955 case elfcpp::R_386_TLS_LE: // Local-exec
2956 case elfcpp::R_386_TLS_LE_32:
2957 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
2958 view, address, view_size);
2959 break;
2960
2961 case elfcpp::R_386_32PLT:
2962 case elfcpp::R_386_TLS_GD_32:
2963 case elfcpp::R_386_TLS_GD_PUSH:
2964 case elfcpp::R_386_TLS_GD_CALL:
2965 case elfcpp::R_386_TLS_GD_POP:
2966 case elfcpp::R_386_TLS_LDM_32:
2967 case elfcpp::R_386_TLS_LDM_PUSH:
2968 case elfcpp::R_386_TLS_LDM_CALL:
2969 case elfcpp::R_386_TLS_LDM_POP:
2970 case elfcpp::R_386_USED_BY_INTEL_200:
2971 default:
2972 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2973 _("unsupported reloc %u"),
2974 r_type);
2975 break;
2976 }
2977
2978 return true;
2979 }
2980
2981 // Perform a TLS relocation.
2982
2983 inline void
2984 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
2985 Target_i386* target,
2986 size_t relnum,
2987 const elfcpp::Rel<32, false>& rel,
2988 unsigned int r_type,
2989 const Sized_symbol<32>* gsym,
2990 const Symbol_value<32>* psymval,
2991 unsigned char* view,
2992 elfcpp::Elf_types<32>::Elf_Addr,
2993 section_size_type view_size)
2994 {
2995 Output_segment* tls_segment = relinfo->layout->tls_segment();
2996
2997 const Sized_relobj_file<32, false>* object = relinfo->object;
2998
2999 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
3000
3001 const bool is_final = (gsym == NULL
3002 ? !parameters->options().shared()
3003 : gsym->final_value_is_known());
3004 const tls::Tls_optimization optimized_type
3005 = Target_i386::optimize_tls_reloc(is_final, r_type);
3006 switch (r_type)
3007 {
3008 case elfcpp::R_386_TLS_GD: // Global-dynamic
3009 if (optimized_type == tls::TLSOPT_TO_LE)
3010 {
3011 if (tls_segment == NULL)
3012 {
3013 gold_assert(parameters->errors()->error_count() > 0
3014 || issue_undefined_symbol_error(gsym));
3015 return;
3016 }
3017 this->tls_gd_to_le(relinfo, relnum, tls_segment,
3018 rel, r_type, value, view,
3019 view_size);
3020 break;
3021 }
3022 else
3023 {
3024 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3025 ? GOT_TYPE_TLS_NOFFSET
3026 : GOT_TYPE_TLS_PAIR);
3027 unsigned int got_offset;
3028 if (gsym != NULL)
3029 {
3030 gold_assert(gsym->has_got_offset(got_type));
3031 got_offset = gsym->got_offset(got_type) - target->got_size();
3032 }
3033 else
3034 {
3035 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3036 gold_assert(object->local_has_got_offset(r_sym, got_type));
3037 got_offset = (object->local_got_offset(r_sym, got_type)
3038 - target->got_size());
3039 }
3040 if (optimized_type == tls::TLSOPT_TO_IE)
3041 {
3042 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
3043 got_offset, view, view_size);
3044 break;
3045 }
3046 else if (optimized_type == tls::TLSOPT_NONE)
3047 {
3048 // Relocate the field with the offset of the pair of GOT
3049 // entries.
3050 Relocate_functions<32, false>::rel32(view, got_offset);
3051 break;
3052 }
3053 }
3054 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3055 _("unsupported reloc %u"),
3056 r_type);
3057 break;
3058
3059 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3060 case elfcpp::R_386_TLS_DESC_CALL:
3061 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3062 if (optimized_type == tls::TLSOPT_TO_LE)
3063 {
3064 if (tls_segment == NULL)
3065 {
3066 gold_assert(parameters->errors()->error_count() > 0
3067 || issue_undefined_symbol_error(gsym));
3068 return;
3069 }
3070 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3071 rel, r_type, value, view,
3072 view_size);
3073 break;
3074 }
3075 else
3076 {
3077 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3078 ? GOT_TYPE_TLS_NOFFSET
3079 : GOT_TYPE_TLS_DESC);
3080 unsigned int got_offset = 0;
3081 if (r_type == elfcpp::R_386_TLS_GOTDESC
3082 && optimized_type == tls::TLSOPT_NONE)
3083 {
3084 // We created GOT entries in the .got.tlsdesc portion of
3085 // the .got.plt section, but the offset stored in the
3086 // symbol is the offset within .got.tlsdesc.
3087 got_offset = (target->got_size()
3088 + target->got_plt_section()->data_size());
3089 }
3090 if (gsym != NULL)
3091 {
3092 gold_assert(gsym->has_got_offset(got_type));
3093 got_offset += gsym->got_offset(got_type) - target->got_size();
3094 }
3095 else
3096 {
3097 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3098 gold_assert(object->local_has_got_offset(r_sym, got_type));
3099 got_offset += (object->local_got_offset(r_sym, got_type)
3100 - target->got_size());
3101 }
3102 if (optimized_type == tls::TLSOPT_TO_IE)
3103 {
3104 if (tls_segment == NULL)
3105 {
3106 gold_assert(parameters->errors()->error_count() > 0
3107 || issue_undefined_symbol_error(gsym));
3108 return;
3109 }
3110 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
3111 got_offset, view, view_size);
3112 break;
3113 }
3114 else if (optimized_type == tls::TLSOPT_NONE)
3115 {
3116 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3117 {
3118 // Relocate the field with the offset of the pair of GOT
3119 // entries.
3120 Relocate_functions<32, false>::rel32(view, got_offset);
3121 }
3122 break;
3123 }
3124 }
3125 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3126 _("unsupported reloc %u"),
3127 r_type);
3128 break;
3129
3130 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3131 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
3132 {
3133 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3134 _("both SUN and GNU model "
3135 "TLS relocations"));
3136 break;
3137 }
3138 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3139 if (optimized_type == tls::TLSOPT_TO_LE)
3140 {
3141 if (tls_segment == NULL)
3142 {
3143 gold_assert(parameters->errors()->error_count() > 0
3144 || issue_undefined_symbol_error(gsym));
3145 return;
3146 }
3147 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
3148 value, view, view_size);
3149 break;
3150 }
3151 else if (optimized_type == tls::TLSOPT_NONE)
3152 {
3153 // Relocate the field with the offset of the GOT entry for
3154 // the module index.
3155 unsigned int got_offset;
3156 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3157 - target->got_size());
3158 Relocate_functions<32, false>::rel32(view, got_offset);
3159 break;
3160 }
3161 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3162 _("unsupported reloc %u"),
3163 r_type);
3164 break;
3165
3166 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3167 if (optimized_type == tls::TLSOPT_TO_LE)
3168 {
3169 // This reloc can appear in debugging sections, in which
3170 // case we must not convert to local-exec. We decide what
3171 // to do based on whether the section is marked as
3172 // containing executable code. That is what the GNU linker
3173 // does as well.
3174 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
3175 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
3176 {
3177 if (tls_segment == NULL)
3178 {
3179 gold_assert(parameters->errors()->error_count() > 0
3180 || issue_undefined_symbol_error(gsym));
3181 return;
3182 }
3183 value -= tls_segment->memsz();
3184 }
3185 }
3186 Relocate_functions<32, false>::rel32(view, value);
3187 break;
3188
3189 case elfcpp::R_386_TLS_IE: // Initial-exec
3190 case elfcpp::R_386_TLS_GOTIE:
3191 case elfcpp::R_386_TLS_IE_32:
3192 if (optimized_type == tls::TLSOPT_TO_LE)
3193 {
3194 if (tls_segment == NULL)
3195 {
3196 gold_assert(parameters->errors()->error_count() > 0
3197 || issue_undefined_symbol_error(gsym));
3198 return;
3199 }
3200 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3201 rel, r_type, value, view,
3202 view_size);
3203 break;
3204 }
3205 else if (optimized_type == tls::TLSOPT_NONE)
3206 {
3207 // Relocate the field with the offset of the GOT entry for
3208 // the tp-relative offset of the symbol.
3209 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
3210 ? GOT_TYPE_TLS_OFFSET
3211 : GOT_TYPE_TLS_NOFFSET);
3212 unsigned int got_offset;
3213 if (gsym != NULL)
3214 {
3215 gold_assert(gsym->has_got_offset(got_type));
3216 got_offset = gsym->got_offset(got_type);
3217 }
3218 else
3219 {
3220 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3221 gold_assert(object->local_has_got_offset(r_sym, got_type));
3222 got_offset = object->local_got_offset(r_sym, got_type);
3223 }
3224 // For the R_386_TLS_IE relocation, we need to apply the
3225 // absolute address of the GOT entry.
3226 if (r_type == elfcpp::R_386_TLS_IE)
3227 got_offset += target->got_plt_section()->address();
3228 // All GOT offsets are relative to the end of the GOT.
3229 got_offset -= target->got_size();
3230 Relocate_functions<32, false>::rel32(view, got_offset);
3231 break;
3232 }
3233 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3234 _("unsupported reloc %u"),
3235 r_type);
3236 break;
3237
3238 case elfcpp::R_386_TLS_LE: // Local-exec
3239 // If we're creating a shared library, a dynamic relocation will
3240 // have been created for this location, so do not apply it now.
3241 if (!parameters->options().shared())
3242 {
3243 if (tls_segment == NULL)
3244 {
3245 gold_assert(parameters->errors()->error_count() > 0
3246 || issue_undefined_symbol_error(gsym));
3247 return;
3248 }
3249 value -= tls_segment->memsz();
3250 Relocate_functions<32, false>::rel32(view, value);
3251 }
3252 break;
3253
3254 case elfcpp::R_386_TLS_LE_32:
3255 // If we're creating a shared library, a dynamic relocation will
3256 // have been created for this location, so do not apply it now.
3257 if (!parameters->options().shared())
3258 {
3259 if (tls_segment == NULL)
3260 {
3261 gold_assert(parameters->errors()->error_count() > 0
3262 || issue_undefined_symbol_error(gsym));
3263 return;
3264 }
3265 value = tls_segment->memsz() - value;
3266 Relocate_functions<32, false>::rel32(view, value);
3267 }
3268 break;
3269 }
3270 }
3271
3272 // Do a relocation in which we convert a TLS General-Dynamic to a
3273 // Local-Exec.
3274
3275 inline void
3276 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
3277 size_t relnum,
3278 Output_segment* tls_segment,
3279 const elfcpp::Rel<32, false>& rel,
3280 unsigned int,
3281 elfcpp::Elf_types<32>::Elf_Addr value,
3282 unsigned char* view,
3283 section_size_type view_size)
3284 {
3285 // leal foo(,%reg,1),%eax; call ___tls_get_addr
3286 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3287 // leal foo(%reg),%eax; call ___tls_get_addr
3288 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3289
3290 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3291 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3292
3293 unsigned char op1 = view[-1];
3294 unsigned char op2 = view[-2];
3295
3296 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3297 op2 == 0x8d || op2 == 0x04);
3298 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3299
3300 int roff = 5;
3301
3302 if (op2 == 0x04)
3303 {
3304 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3305 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3306 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3307 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3308 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3309 }
3310 else
3311 {
3312 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3313 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3314 if (rel.get_r_offset() + 9 < view_size
3315 && view[9] == 0x90)
3316 {
3317 // There is a trailing nop. Use the size byte subl.
3318 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3319 roff = 6;
3320 }
3321 else
3322 {
3323 // Use the five byte subl.
3324 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3325 }
3326 }
3327
3328 value = tls_segment->memsz() - value;
3329 Relocate_functions<32, false>::rel32(view + roff, value);
3330
3331 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3332 // We can skip it.
3333 this->skip_call_tls_get_addr_ = true;
3334 }
3335
3336 // Do a relocation in which we convert a TLS General-Dynamic to an
3337 // Initial-Exec.
3338
3339 inline void
3340 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
3341 size_t relnum,
3342 Output_segment*,
3343 const elfcpp::Rel<32, false>& rel,
3344 unsigned int,
3345 elfcpp::Elf_types<32>::Elf_Addr value,
3346 unsigned char* view,
3347 section_size_type view_size)
3348 {
3349 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
3350 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3351 // leal foo(%ebx),%eax; call ___tls_get_addr; nop
3352 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3353
3354 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3355 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3356
3357 unsigned char op1 = view[-1];
3358 unsigned char op2 = view[-2];
3359
3360 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3361 op2 == 0x8d || op2 == 0x04);
3362 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3363
3364 int roff;
3365
3366 if (op2 == 0x04)
3367 {
3368 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3369 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3370 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3371 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3372 roff = 5;
3373 }
3374 else
3375 {
3376 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 10);
3377 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3378 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3379 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[9] == 0x90);
3380 roff = 6;
3381 }
3382
3383 memcpy(view + roff - 8, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
3384 Relocate_functions<32, false>::rel32(view + roff, value);
3385
3386 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3387 // We can skip it.
3388 this->skip_call_tls_get_addr_ = true;
3389 }
3390
3391 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3392 // General-Dynamic to a Local-Exec.
3393
3394 inline void
3395 Target_i386::Relocate::tls_desc_gd_to_le(
3396 const Relocate_info<32, false>* relinfo,
3397 size_t relnum,
3398 Output_segment* tls_segment,
3399 const elfcpp::Rel<32, false>& rel,
3400 unsigned int r_type,
3401 elfcpp::Elf_types<32>::Elf_Addr value,
3402 unsigned char* view,
3403 section_size_type view_size)
3404 {
3405 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3406 {
3407 // leal foo@TLSDESC(%ebx), %eax
3408 // ==> leal foo@NTPOFF, %eax
3409 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3410 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3411 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3412 view[-2] == 0x8d && view[-1] == 0x83);
3413 view[-1] = 0x05;
3414 value -= tls_segment->memsz();
3415 Relocate_functions<32, false>::rel32(view, value);
3416 }
3417 else
3418 {
3419 // call *foo@TLSCALL(%eax)
3420 // ==> nop; nop
3421 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3422 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3423 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3424 view[0] == 0xff && view[1] == 0x10);
3425 view[0] = 0x66;
3426 view[1] = 0x90;
3427 }
3428 }
3429
3430 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3431 // General-Dynamic to an Initial-Exec.
3432
3433 inline void
3434 Target_i386::Relocate::tls_desc_gd_to_ie(
3435 const Relocate_info<32, false>* relinfo,
3436 size_t relnum,
3437 Output_segment*,
3438 const elfcpp::Rel<32, false>& rel,
3439 unsigned int r_type,
3440 elfcpp::Elf_types<32>::Elf_Addr value,
3441 unsigned char* view,
3442 section_size_type view_size)
3443 {
3444 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3445 {
3446 // leal foo@TLSDESC(%ebx), %eax
3447 // ==> movl foo@GOTNTPOFF(%ebx), %eax
3448 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3449 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3450 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3451 view[-2] == 0x8d && view[-1] == 0x83);
3452 view[-2] = 0x8b;
3453 Relocate_functions<32, false>::rel32(view, value);
3454 }
3455 else
3456 {
3457 // call *foo@TLSCALL(%eax)
3458 // ==> nop; nop
3459 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3460 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3461 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3462 view[0] == 0xff && view[1] == 0x10);
3463 view[0] = 0x66;
3464 view[1] = 0x90;
3465 }
3466 }
3467
3468 // Do a relocation in which we convert a TLS Local-Dynamic to a
3469 // Local-Exec.
3470
3471 inline void
3472 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
3473 size_t relnum,
3474 Output_segment*,
3475 const elfcpp::Rel<32, false>& rel,
3476 unsigned int,
3477 elfcpp::Elf_types<32>::Elf_Addr,
3478 unsigned char* view,
3479 section_size_type view_size)
3480 {
3481 // leal foo(%reg), %eax; call ___tls_get_addr
3482 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
3483
3484 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3485 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3486
3487 // FIXME: Does this test really always pass?
3488 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3489 view[-2] == 0x8d && view[-1] == 0x83);
3490
3491 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3492
3493 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
3494
3495 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3496 // We can skip it.
3497 this->skip_call_tls_get_addr_ = true;
3498 }
3499
3500 // Do a relocation in which we convert a TLS Initial-Exec to a
3501 // Local-Exec.
3502
3503 inline void
3504 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
3505 size_t relnum,
3506 Output_segment* tls_segment,
3507 const elfcpp::Rel<32, false>& rel,
3508 unsigned int r_type,
3509 elfcpp::Elf_types<32>::Elf_Addr value,
3510 unsigned char* view,
3511 section_size_type view_size)
3512 {
3513 // We have to actually change the instructions, which means that we
3514 // need to examine the opcodes to figure out which instruction we
3515 // are looking at.
3516 if (r_type == elfcpp::R_386_TLS_IE)
3517 {
3518 // movl %gs:XX,%eax ==> movl $YY,%eax
3519 // movl %gs:XX,%reg ==> movl $YY,%reg
3520 // addl %gs:XX,%reg ==> addl $YY,%reg
3521 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
3522 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3523
3524 unsigned char op1 = view[-1];
3525 if (op1 == 0xa1)
3526 {
3527 // movl XX,%eax ==> movl $YY,%eax
3528 view[-1] = 0xb8;
3529 }
3530 else
3531 {
3532 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3533
3534 unsigned char op2 = view[-2];
3535 if (op2 == 0x8b)
3536 {
3537 // movl XX,%reg ==> movl $YY,%reg
3538 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3539 (op1 & 0xc7) == 0x05);
3540 view[-2] = 0xc7;
3541 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3542 }
3543 else if (op2 == 0x03)
3544 {
3545 // addl XX,%reg ==> addl $YY,%reg
3546 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3547 (op1 & 0xc7) == 0x05);
3548 view[-2] = 0x81;
3549 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3550 }
3551 else
3552 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3553 }
3554 }
3555 else
3556 {
3557 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3558 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3559 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3560 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3561 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3562
3563 unsigned char op1 = view[-1];
3564 unsigned char op2 = view[-2];
3565 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3566 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
3567 if (op2 == 0x8b)
3568 {
3569 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3570 view[-2] = 0xc7;
3571 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3572 }
3573 else if (op2 == 0x2b)
3574 {
3575 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3576 view[-2] = 0x81;
3577 view[-1] = 0xe8 | ((op1 >> 3) & 7);
3578 }
3579 else if (op2 == 0x03)
3580 {
3581 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3582 view[-2] = 0x81;
3583 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3584 }
3585 else
3586 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3587 }
3588
3589 value = tls_segment->memsz() - value;
3590 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
3591 value = - value;
3592
3593 Relocate_functions<32, false>::rel32(view, value);
3594 }
3595
3596 // Relocate section data.
3597
3598 void
3599 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
3600 unsigned int sh_type,
3601 const unsigned char* prelocs,
3602 size_t reloc_count,
3603 Output_section* output_section,
3604 bool needs_special_offset_handling,
3605 unsigned char* view,
3606 elfcpp::Elf_types<32>::Elf_Addr address,
3607 section_size_type view_size,
3608 const Reloc_symbol_changes* reloc_symbol_changes)
3609 {
3610 gold_assert(sh_type == elfcpp::SHT_REL);
3611
3612 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
3613 Target_i386::Relocate, gold::Default_comdat_behavior>(
3614 relinfo,
3615 this,
3616 prelocs,
3617 reloc_count,
3618 output_section,
3619 needs_special_offset_handling,
3620 view,
3621 address,
3622 view_size,
3623 reloc_symbol_changes);
3624 }
3625
3626 // Return the size of a relocation while scanning during a relocatable
3627 // link.
3628
3629 unsigned int
3630 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
3631 unsigned int r_type,
3632 Relobj* object)
3633 {
3634 switch (r_type)
3635 {
3636 case elfcpp::R_386_NONE:
3637 case elfcpp::R_386_GNU_VTINHERIT:
3638 case elfcpp::R_386_GNU_VTENTRY:
3639 case elfcpp::R_386_TLS_GD: // Global-dynamic
3640 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3641 case elfcpp::R_386_TLS_DESC_CALL:
3642 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3643 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3644 case elfcpp::R_386_TLS_IE: // Initial-exec
3645 case elfcpp::R_386_TLS_IE_32:
3646 case elfcpp::R_386_TLS_GOTIE:
3647 case elfcpp::R_386_TLS_LE: // Local-exec
3648 case elfcpp::R_386_TLS_LE_32:
3649 return 0;
3650
3651 case elfcpp::R_386_32:
3652 case elfcpp::R_386_PC32:
3653 case elfcpp::R_386_GOT32:
3654 case elfcpp::R_386_GOT32X:
3655 case elfcpp::R_386_PLT32:
3656 case elfcpp::R_386_GOTOFF:
3657 case elfcpp::R_386_GOTPC:
3658 return 4;
3659
3660 case elfcpp::R_386_16:
3661 case elfcpp::R_386_PC16:
3662 return 2;
3663
3664 case elfcpp::R_386_8:
3665 case elfcpp::R_386_PC8:
3666 return 1;
3667
3668 // These are relocations which should only be seen by the
3669 // dynamic linker, and should never be seen here.
3670 case elfcpp::R_386_COPY:
3671 case elfcpp::R_386_GLOB_DAT:
3672 case elfcpp::R_386_JUMP_SLOT:
3673 case elfcpp::R_386_RELATIVE:
3674 case elfcpp::R_386_IRELATIVE:
3675 case elfcpp::R_386_TLS_TPOFF:
3676 case elfcpp::R_386_TLS_DTPMOD32:
3677 case elfcpp::R_386_TLS_DTPOFF32:
3678 case elfcpp::R_386_TLS_TPOFF32:
3679 case elfcpp::R_386_TLS_DESC:
3680 object->error(_("unexpected reloc %u in object file"), r_type);
3681 return 0;
3682
3683 case elfcpp::R_386_32PLT:
3684 case elfcpp::R_386_TLS_GD_32:
3685 case elfcpp::R_386_TLS_GD_PUSH:
3686 case elfcpp::R_386_TLS_GD_CALL:
3687 case elfcpp::R_386_TLS_GD_POP:
3688 case elfcpp::R_386_TLS_LDM_32:
3689 case elfcpp::R_386_TLS_LDM_PUSH:
3690 case elfcpp::R_386_TLS_LDM_CALL:
3691 case elfcpp::R_386_TLS_LDM_POP:
3692 case elfcpp::R_386_USED_BY_INTEL_200:
3693 default:
3694 object->error(_("unsupported reloc %u in object file"), r_type);
3695 return 0;
3696 }
3697 }
3698
3699 // Scan the relocs during a relocatable link.
3700
3701 void
3702 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
3703 Layout* layout,
3704 Sized_relobj_file<32, false>* object,
3705 unsigned int data_shndx,
3706 unsigned int sh_type,
3707 const unsigned char* prelocs,
3708 size_t reloc_count,
3709 Output_section* output_section,
3710 bool needs_special_offset_handling,
3711 size_t local_symbol_count,
3712 const unsigned char* plocal_symbols,
3713 Relocatable_relocs* rr)
3714 {
3715 gold_assert(sh_type == elfcpp::SHT_REL);
3716
3717 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
3718 Relocatable_size_for_reloc> Scan_relocatable_relocs;
3719
3720 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
3721 Scan_relocatable_relocs>(
3722 symtab,
3723 layout,
3724 object,
3725 data_shndx,
3726 prelocs,
3727 reloc_count,
3728 output_section,
3729 needs_special_offset_handling,
3730 local_symbol_count,
3731 plocal_symbols,
3732 rr);
3733 }
3734
3735 // Emit relocations for a section.
3736
3737 void
3738 Target_i386::relocate_relocs(
3739 const Relocate_info<32, false>* relinfo,
3740 unsigned int sh_type,
3741 const unsigned char* prelocs,
3742 size_t reloc_count,
3743 Output_section* output_section,
3744 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
3745 unsigned char* view,
3746 elfcpp::Elf_types<32>::Elf_Addr view_address,
3747 section_size_type view_size,
3748 unsigned char* reloc_view,
3749 section_size_type reloc_view_size)
3750 {
3751 gold_assert(sh_type == elfcpp::SHT_REL);
3752
3753 gold::relocate_relocs<32, false, elfcpp::SHT_REL>(
3754 relinfo,
3755 prelocs,
3756 reloc_count,
3757 output_section,
3758 offset_in_output_section,
3759 view,
3760 view_address,
3761 view_size,
3762 reloc_view,
3763 reloc_view_size);
3764 }
3765
3766 // Return the value to use for a dynamic which requires special
3767 // treatment. This is how we support equality comparisons of function
3768 // pointers across shared library boundaries, as described in the
3769 // processor specific ABI supplement.
3770
3771 uint64_t
3772 Target_i386::do_dynsym_value(const Symbol* gsym) const
3773 {
3774 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3775 return this->plt_address_for_global(gsym);
3776 }
3777
3778 // Return a string used to fill a code section with nops to take up
3779 // the specified length.
3780
3781 std::string
3782 Target_i386::do_code_fill(section_size_type length) const
3783 {
3784 if (length >= 16)
3785 {
3786 // Build a jmp instruction to skip over the bytes.
3787 unsigned char jmp[5];
3788 jmp[0] = 0xe9;
3789 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3790 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3791 + std::string(length - 5, static_cast<char>(0x90)));
3792 }
3793
3794 // Nop sequences of various lengths.
3795 const char nop1[1] = { '\x90' }; // nop
3796 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
3797 const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi
3798 const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3799 '\x00'};
3800 const char nop5[5] = { '\x90', '\x8d', '\x74', // nop
3801 '\x26', '\x00' }; // leal 0(%esi,1),%esi
3802 const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3803 '\x00', '\x00', '\x00' };
3804 const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3805 '\x00', '\x00', '\x00',
3806 '\x00' };
3807 const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop
3808 '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi
3809 '\x00', '\x00' };
3810 const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi
3811 '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi
3812 '\x00', '\x00', '\x00' };
3813 const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi
3814 '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi
3815 '\x00', '\x00', '\x00',
3816 '\x00' };
3817 const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3818 '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi
3819 '\x27', '\x00', '\x00',
3820 '\x00', '\x00' };
3821 const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3822 '\x00', '\x00', '\x00', // leal 0L(%edi),%edi
3823 '\x8d', '\xbf', '\x00',
3824 '\x00', '\x00', '\x00' };
3825 const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3826 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3827 '\x8d', '\xbc', '\x27',
3828 '\x00', '\x00', '\x00',
3829 '\x00' };
3830 const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3831 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3832 '\x00', '\x8d', '\xbc',
3833 '\x27', '\x00', '\x00',
3834 '\x00', '\x00' };
3835 const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15
3836 '\x90', '\x90', '\x90', // nop,nop,nop,...
3837 '\x90', '\x90', '\x90',
3838 '\x90', '\x90', '\x90',
3839 '\x90', '\x90', '\x90' };
3840
3841 const char* nops[16] = {
3842 NULL,
3843 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3844 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3845 };
3846
3847 return std::string(nops[length], length);
3848 }
3849
3850 // Return the value to use for the base of a DW_EH_PE_datarel offset
3851 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3852 // assembler can not write out the difference between two labels in
3853 // different sections, so instead of using a pc-relative value they
3854 // use an offset from the GOT.
3855
3856 uint64_t
3857 Target_i386::do_ehframe_datarel_base() const
3858 {
3859 gold_assert(this->global_offset_table_ != NULL);
3860 Symbol* sym = this->global_offset_table_;
3861 Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym);
3862 return ssym->value();
3863 }
3864
3865 // Return whether SYM should be treated as a call to a non-split
3866 // function. We don't want that to be true of a call to a
3867 // get_pc_thunk function.
3868
3869 bool
3870 Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
3871 {
3872 return (sym->type() == elfcpp::STT_FUNC
3873 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
3874 }
3875
3876 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3877 // compiled with -fsplit-stack. The function calls non-split-stack
3878 // code. We have to change the function so that it always ensures
3879 // that it has enough stack space to run some random function.
3880
3881 void
3882 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
3883 section_offset_type fnoffset,
3884 section_size_type fnsize,
3885 const unsigned char*,
3886 size_t,
3887 unsigned char* view,
3888 section_size_type view_size,
3889 std::string* from,
3890 std::string* to) const
3891 {
3892 // The function starts with a comparison of the stack pointer and a
3893 // field in the TCB. This is followed by a jump.
3894
3895 // cmp %gs:NN,%esp
3896 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
3897 && fnsize > 7)
3898 {
3899 // We will call __morestack if the carry flag is set after this
3900 // comparison. We turn the comparison into an stc instruction
3901 // and some nops.
3902 view[fnoffset] = '\xf9';
3903 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
3904 }
3905 // lea NN(%esp),%ecx
3906 // lea NN(%esp),%edx
3907 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
3908 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
3909 && fnsize > 7)
3910 {
3911 // This is loading an offset from the stack pointer for a
3912 // comparison. The offset is negative, so we decrease the
3913 // offset by the amount of space we need for the stack. This
3914 // means we will avoid calling __morestack if there happens to
3915 // be plenty of space on the stack already.
3916 unsigned char* pval = view + fnoffset + 3;
3917 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3918 val -= parameters->options().split_stack_adjust_size();
3919 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3920 }
3921 else
3922 {
3923 if (!object->has_no_split_stack())
3924 object->error(_("failed to match split-stack sequence at "
3925 "section %u offset %0zx"),
3926 shndx, static_cast<size_t>(fnoffset));
3927 return;
3928 }
3929
3930 // We have to change the function so that it calls
3931 // __morestack_non_split instead of __morestack. The former will
3932 // allocate additional stack space.
3933 *from = "__morestack";
3934 *to = "__morestack_non_split";
3935 }
3936
3937 // The selector for i386 object files. Note this is never instantiated
3938 // directly. It's only used in Target_selector_i386_nacl, below.
3939
3940 class Target_selector_i386 : public Target_selector_freebsd
3941 {
3942 public:
3943 Target_selector_i386()
3944 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
3945 "elf32-i386", "elf32-i386-freebsd",
3946 "elf_i386")
3947 { }
3948
3949 Target*
3950 do_instantiate_target()
3951 { return new Target_i386(); }
3952 };
3953
3954 // NaCl variant. It uses different PLT contents.
3955
3956 class Output_data_plt_i386_nacl : public Output_data_plt_i386
3957 {
3958 public:
3959 Output_data_plt_i386_nacl(Layout* layout,
3960 Output_data_got_plt_i386* got_plt,
3961 Output_data_space* got_irelative)
3962 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
3963 { }
3964
3965 protected:
3966 virtual unsigned int
3967 do_get_plt_entry_size() const
3968 { return plt_entry_size; }
3969
3970 virtual void
3971 do_add_eh_frame(Layout* layout)
3972 {
3973 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
3974 plt_eh_frame_fde, plt_eh_frame_fde_size);
3975 }
3976
3977 // The size of an entry in the PLT.
3978 static const int plt_entry_size = 64;
3979
3980 // The .eh_frame unwind information for the PLT.
3981 static const int plt_eh_frame_fde_size = 32;
3982 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
3983 };
3984
3985 class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl
3986 {
3987 public:
3988 Output_data_plt_i386_nacl_exec(Layout* layout,
3989 Output_data_got_plt_i386* got_plt,
3990 Output_data_space* got_irelative)
3991 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
3992 { }
3993
3994 protected:
3995 virtual void
3996 do_fill_first_plt_entry(unsigned char* pov,
3997 elfcpp::Elf_types<32>::Elf_Addr got_address);
3998
3999 virtual unsigned int
4000 do_fill_plt_entry(unsigned char* pov,
4001 elfcpp::Elf_types<32>::Elf_Addr got_address,
4002 unsigned int got_offset,
4003 unsigned int plt_offset,
4004 unsigned int plt_rel_offset);
4005
4006 private:
4007 // The first entry in the PLT for an executable.
4008 static const unsigned char first_plt_entry[plt_entry_size];
4009
4010 // Other entries in the PLT for an executable.
4011 static const unsigned char plt_entry[plt_entry_size];
4012 };
4013
4014 class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl
4015 {
4016 public:
4017 Output_data_plt_i386_nacl_dyn(Layout* layout,
4018 Output_data_got_plt_i386* got_plt,
4019 Output_data_space* got_irelative)
4020 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
4021 { }
4022
4023 protected:
4024 virtual void
4025 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
4026
4027 virtual unsigned int
4028 do_fill_plt_entry(unsigned char* pov,
4029 elfcpp::Elf_types<32>::Elf_Addr,
4030 unsigned int got_offset,
4031 unsigned int plt_offset,
4032 unsigned int plt_rel_offset);
4033
4034 private:
4035 // The first entry in the PLT for a shared object.
4036 static const unsigned char first_plt_entry[plt_entry_size];
4037
4038 // Other entries in the PLT for a shared object.
4039 static const unsigned char plt_entry[plt_entry_size];
4040 };
4041
4042 class Target_i386_nacl : public Target_i386
4043 {
4044 public:
4045 Target_i386_nacl()
4046 : Target_i386(&i386_nacl_info)
4047 { }
4048
4049 protected:
4050 virtual Output_data_plt_i386*
4051 do_make_data_plt(Layout* layout,
4052 Output_data_got_plt_i386* got_plt,
4053 Output_data_space* got_irelative,
4054 bool dyn)
4055 {
4056 if (dyn)
4057 return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative);
4058 else
4059 return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative);
4060 }
4061
4062 virtual std::string
4063 do_code_fill(section_size_type length) const;
4064
4065 private:
4066 static const Target::Target_info i386_nacl_info;
4067 };
4068
4069 const Target::Target_info Target_i386_nacl::i386_nacl_info =
4070 {
4071 32, // size
4072 false, // is_big_endian
4073 elfcpp::EM_386, // machine_code
4074 false, // has_make_symbol
4075 false, // has_resolve
4076 true, // has_code_fill
4077 true, // is_default_stack_executable
4078 true, // can_icf_inline_merge_sections
4079 '\0', // wrap_char
4080 "/lib/ld-nacl-x86-32.so.1", // dynamic_linker
4081 0x20000, // default_text_segment_address
4082 0x10000, // abi_pagesize (overridable by -z max-page-size)
4083 0x10000, // common_pagesize (overridable by -z common-page-size)
4084 true, // isolate_execinstr
4085 0x10000000, // rosegment_gap
4086 elfcpp::SHN_UNDEF, // small_common_shndx
4087 elfcpp::SHN_UNDEF, // large_common_shndx
4088 0, // small_common_section_flags
4089 0, // large_common_section_flags
4090 NULL, // attributes_section
4091 NULL, // attributes_vendor
4092 "_start", // entry_symbol_name
4093 32, // hash_entry_size
4094 };
4095
4096 #define NACLMASK 0xe0 // 32-byte alignment mask
4097
4098 const unsigned char
4099 Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] =
4100 {
4101 0xff, 0x35, // pushl contents of memory address
4102 0, 0, 0, 0, // replaced with address of .got + 4
4103 0x8b, 0x0d, // movl contents of address, %ecx
4104 0, 0, 0, 0, // replaced with address of .got + 8
4105 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4106 0xff, 0xe1, // jmp *%ecx
4107 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4108 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4109 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4110 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4111 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4112 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4113 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4114 0x90, 0x90, 0x90, 0x90, 0x90
4115 };
4116
4117 void
4118 Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry(
4119 unsigned char* pov,
4120 elfcpp::Elf_types<32>::Elf_Addr got_address)
4121 {
4122 memcpy(pov, first_plt_entry, plt_entry_size);
4123 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
4124 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
4125 }
4126
4127 // The first entry in the PLT for a shared object.
4128
4129 const unsigned char
4130 Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] =
4131 {
4132 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
4133 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx
4134 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4135 0xff, 0xe1, // jmp *%ecx
4136 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4137 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4138 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4139 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4140 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4141 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4142 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4143 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4144 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4145 0x90, 0x90, 0x90, 0x90, 0x90 // nops
4146 };
4147
4148 void
4149 Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry(
4150 unsigned char* pov,
4151 elfcpp::Elf_types<32>::Elf_Addr)
4152 {
4153 memcpy(pov, first_plt_entry, plt_entry_size);
4154 }
4155
4156 // Subsequent entries in the PLT for an executable.
4157
4158 const unsigned char
4159 Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] =
4160 {
4161 0x8b, 0x0d, // movl contents of address, %ecx */
4162 0, 0, 0, 0, // replaced with address of symbol in .got
4163 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4164 0xff, 0xe1, // jmp *%ecx
4165
4166 // Pad to the next 32-byte boundary with nop instructions.
4167 0x90,
4168 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4169 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4170
4171 // Lazy GOT entries point here (32-byte aligned).
4172 0x68, // pushl immediate
4173 0, 0, 0, 0, // replaced with offset into relocation table
4174 0xe9, // jmp relative
4175 0, 0, 0, 0, // replaced with offset to start of .plt
4176
4177 // Pad to the next 32-byte boundary with nop instructions.
4178 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4179 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4180 0x90, 0x90
4181 };
4182
4183 unsigned int
4184 Output_data_plt_i386_nacl_exec::do_fill_plt_entry(
4185 unsigned char* pov,
4186 elfcpp::Elf_types<32>::Elf_Addr got_address,
4187 unsigned int got_offset,
4188 unsigned int plt_offset,
4189 unsigned int plt_rel_offset)
4190 {
4191 memcpy(pov, plt_entry, plt_entry_size);
4192 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4193 got_address + got_offset);
4194 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4195 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4196 return 32;
4197 }
4198
4199 // Subsequent entries in the PLT for a shared object.
4200
4201 const unsigned char
4202 Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] =
4203 {
4204 0x8b, 0x8b, // movl offset(%ebx), %ecx
4205 0, 0, 0, 0, // replaced with offset of symbol in .got
4206 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx
4207 0xff, 0xe1, // jmp *%ecx
4208
4209 // Pad to the next 32-byte boundary with nop instructions.
4210 0x90,
4211 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4212 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4213
4214 // Lazy GOT entries point here (32-byte aligned).
4215 0x68, // pushl immediate
4216 0, 0, 0, 0, // replaced with offset into relocation table.
4217 0xe9, // jmp relative
4218 0, 0, 0, 0, // replaced with offset to start of .plt.
4219
4220 // Pad to the next 32-byte boundary with nop instructions.
4221 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4222 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4223 0x90, 0x90
4224 };
4225
4226 unsigned int
4227 Output_data_plt_i386_nacl_dyn::do_fill_plt_entry(
4228 unsigned char* pov,
4229 elfcpp::Elf_types<32>::Elf_Addr,
4230 unsigned int got_offset,
4231 unsigned int plt_offset,
4232 unsigned int plt_rel_offset)
4233 {
4234 memcpy(pov, plt_entry, plt_entry_size);
4235 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
4236 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4237 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4238 return 32;
4239 }
4240
4241 const unsigned char
4242 Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] =
4243 {
4244 0, 0, 0, 0, // Replaced with offset to .plt.
4245 0, 0, 0, 0, // Replaced with size of .plt.
4246 0, // Augmentation size.
4247 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
4248 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
4249 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
4250 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
4251 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
4252 13, // Block length.
4253 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
4254 elfcpp::DW_OP_breg8, 0, // Push %eip.
4255 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
4256 elfcpp::DW_OP_and, // & (%eip & 0x3f).
4257 elfcpp::DW_OP_const1u, 37, // Push 0x25.
4258 elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25)
4259 elfcpp::DW_OP_lit2, // Push 2.
4260 elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2)
4261 elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4
4262 elfcpp::DW_CFA_nop, // Align to 32 bytes.
4263 elfcpp::DW_CFA_nop
4264 };
4265
4266 // Return a string used to fill a code section with nops.
4267 // For NaCl, long NOPs are only valid if they do not cross
4268 // bundle alignment boundaries, so keep it simple with one-byte NOPs.
4269 std::string
4270 Target_i386_nacl::do_code_fill(section_size_type length) const
4271 {
4272 return std::string(length, static_cast<char>(0x90));
4273 }
4274
4275 // The selector for i386-nacl object files.
4276
4277 class Target_selector_i386_nacl
4278 : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl>
4279 {
4280 public:
4281 Target_selector_i386_nacl()
4282 : Target_selector_nacl<Target_selector_i386,
4283 Target_i386_nacl>("x86-32",
4284 "elf32-i386-nacl",
4285 "elf_i386_nacl")
4286 { }
4287 };
4288
4289 Target_selector_i386_nacl target_selector_i386;
4290
4291 // IAMCU variant. It uses EM_IAMCU, not EM_386.
4292
4293 class Target_iamcu : public Target_i386
4294 {
4295 public:
4296 Target_iamcu()
4297 : Target_i386(&iamcu_info)
4298 { }
4299
4300 private:
4301 // Information about this specific target which we pass to the
4302 // general Target structure.
4303 static const Target::Target_info iamcu_info;
4304 };
4305
4306 const Target::Target_info Target_iamcu::iamcu_info =
4307 {
4308 32, // size
4309 false, // is_big_endian
4310 elfcpp::EM_IAMCU, // machine_code
4311 false, // has_make_symbol
4312 false, // has_resolve
4313 true, // has_code_fill
4314 true, // is_default_stack_executable
4315 true, // can_icf_inline_merge_sections
4316 '\0', // wrap_char
4317 "/usr/lib/libc.so.1", // dynamic_linker
4318 0x08048000, // default_text_segment_address
4319 0x1000, // abi_pagesize (overridable by -z max-page-size)
4320 0x1000, // common_pagesize (overridable by -z common-page-size)
4321 false, // isolate_execinstr
4322 0, // rosegment_gap
4323 elfcpp::SHN_UNDEF, // small_common_shndx
4324 elfcpp::SHN_UNDEF, // large_common_shndx
4325 0, // small_common_section_flags
4326 0, // large_common_section_flags
4327 NULL, // attributes_section
4328 NULL, // attributes_vendor
4329 "_start", // entry_symbol_name
4330 32, // hash_entry_size
4331 };
4332
4333 class Target_selector_iamcu : public Target_selector
4334 {
4335 public:
4336 Target_selector_iamcu()
4337 : Target_selector(elfcpp::EM_IAMCU, 32, false, "elf32-iamcu",
4338 "elf_iamcu")
4339 { }
4340
4341 Target*
4342 do_instantiate_target()
4343 { return new Target_iamcu(); }
4344 };
4345
4346 Target_selector_iamcu target_selector_iamcu;
4347
4348 } // End anonymous namespace.
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