gdb: add target_ops::supports_displaced_step
[deliverable/binutils-gdb.git] / gold / i386.cc
1 // i386.cc -- i386 target support for gold.
2
3 // Copyright (C) 2006-2020 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cstring>
26
27 #include "elfcpp.h"
28 #include "dwarf.h"
29 #include "parameters.h"
30 #include "reloc.h"
31 #include "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 // Scan the relocs for --emit-relocs.
433 void
434 emit_relocs_scan(Symbol_table* symtab,
435 Layout* layout,
436 Sized_relobj_file<32, false>* object,
437 unsigned int data_shndx,
438 unsigned int sh_type,
439 const unsigned char* prelocs,
440 size_t reloc_count,
441 Output_section* output_section,
442 bool needs_special_offset_handling,
443 size_t local_symbol_count,
444 const unsigned char* plocal_syms,
445 Relocatable_relocs* rr);
446
447 // Emit relocations for a section.
448 void
449 relocate_relocs(const Relocate_info<32, false>*,
450 unsigned int sh_type,
451 const unsigned char* prelocs,
452 size_t reloc_count,
453 Output_section* output_section,
454 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
455 unsigned char* view,
456 elfcpp::Elf_types<32>::Elf_Addr view_address,
457 section_size_type view_size,
458 unsigned char* reloc_view,
459 section_size_type reloc_view_size);
460
461 // Return a string used to fill a code section with nops.
462 std::string
463 do_code_fill(section_size_type length) const;
464
465 // Return whether SYM is defined by the ABI.
466 bool
467 do_is_defined_by_abi(const Symbol* sym) const
468 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
469
470 // Return whether a symbol name implies a local label. The UnixWare
471 // 2.1 cc generates temporary symbols that start with .X, so we
472 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
473 // If so, we should move the .X recognition into
474 // Target::do_is_local_label_name.
475 bool
476 do_is_local_label_name(const char* name) const
477 {
478 if (name[0] == '.' && name[1] == 'X')
479 return true;
480 return Target::do_is_local_label_name(name);
481 }
482
483 // Return the PLT address to use for a global symbol.
484 uint64_t
485 do_plt_address_for_global(const Symbol* gsym) const
486 { return this->plt_section()->address_for_global(gsym); }
487
488 uint64_t
489 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
490 { return this->plt_section()->address_for_local(relobj, symndx); }
491
492 // We can tell whether we take the address of a function.
493 inline bool
494 do_can_check_for_function_pointers() const
495 { return true; }
496
497 // Return the base for a DW_EH_PE_datarel encoding.
498 uint64_t
499 do_ehframe_datarel_base() const;
500
501 // Return whether SYM is call to a non-split function.
502 bool
503 do_is_call_to_non_split(const Symbol* sym, const unsigned char*,
504 const unsigned char*, section_size_type) const;
505
506 // Adjust -fsplit-stack code which calls non-split-stack code.
507 void
508 do_calls_non_split(Relobj* object, unsigned int shndx,
509 section_offset_type fnoffset, section_size_type fnsize,
510 const unsigned char* prelocs, size_t reloc_count,
511 unsigned char* view, section_size_type view_size,
512 std::string* from, std::string* to) const;
513
514 // Return the size of the GOT section.
515 section_size_type
516 got_size() const
517 {
518 gold_assert(this->got_ != NULL);
519 return this->got_->data_size();
520 }
521
522 // Return the number of entries in the GOT.
523 unsigned int
524 got_entry_count() const
525 {
526 if (this->got_ == NULL)
527 return 0;
528 return this->got_size() / 4;
529 }
530
531 // Return the number of entries in the PLT.
532 unsigned int
533 plt_entry_count() const;
534
535 // Return the offset of the first non-reserved PLT entry.
536 unsigned int
537 first_plt_entry_offset() const;
538
539 // Return the size of each PLT entry.
540 unsigned int
541 plt_entry_size() const;
542
543 protected:
544 // Instantiate the plt_ member.
545 // This chooses the right PLT flavor for an executable or a shared object.
546 Output_data_plt_i386*
547 make_data_plt(Layout* layout,
548 Output_data_got_plt_i386* got_plt,
549 Output_data_space* got_irelative,
550 bool dyn)
551 { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); }
552
553 virtual Output_data_plt_i386*
554 do_make_data_plt(Layout* layout,
555 Output_data_got_plt_i386* got_plt,
556 Output_data_space* got_irelative,
557 bool dyn)
558 {
559 if (dyn)
560 return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative);
561 else
562 return new Output_data_plt_i386_exec(layout, got_plt, got_irelative);
563 }
564
565 private:
566 // The class which scans relocations.
567 struct Scan
568 {
569 static inline int
570
571 get_reference_flags(unsigned int r_type);
572
573 inline void
574 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
575 Sized_relobj_file<32, false>* object,
576 unsigned int data_shndx,
577 Output_section* output_section,
578 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
579 const elfcpp::Sym<32, false>& lsym,
580 bool is_discarded);
581
582 inline void
583 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
584 Sized_relobj_file<32, false>* object,
585 unsigned int data_shndx,
586 Output_section* output_section,
587 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
588 Symbol* gsym);
589
590 inline bool
591 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
592 Target_i386* target,
593 Sized_relobj_file<32, false>* object,
594 unsigned int data_shndx,
595 Output_section* output_section,
596 const elfcpp::Rel<32, false>& reloc,
597 unsigned int r_type,
598 const elfcpp::Sym<32, false>& lsym);
599
600 inline bool
601 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
602 Target_i386* target,
603 Sized_relobj_file<32, false>* object,
604 unsigned int data_shndx,
605 Output_section* output_section,
606 const elfcpp::Rel<32, false>& reloc,
607 unsigned int r_type,
608 Symbol* gsym);
609
610 inline bool
611 possible_function_pointer_reloc(unsigned int r_type);
612
613 bool
614 reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*,
615 unsigned int r_type);
616
617 static void
618 unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type);
619
620 static void
621 unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type,
622 Symbol*);
623 };
624
625 // The class which implements relocation.
626 class Relocate
627 {
628 public:
629 Relocate()
630 : skip_call_tls_get_addr_(false),
631 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
632 { }
633
634 ~Relocate()
635 {
636 if (this->skip_call_tls_get_addr_)
637 {
638 // FIXME: This needs to specify the location somehow.
639 gold_error(_("missing expected TLS relocation"));
640 }
641 }
642
643 // Return whether the static relocation needs to be applied.
644 inline bool
645 should_apply_static_reloc(const Sized_symbol<32>* gsym,
646 unsigned int r_type,
647 bool is_32bit,
648 Output_section* output_section);
649
650 // Do a relocation. Return false if the caller should not issue
651 // any warnings about this relocation.
652 inline bool
653 relocate(const Relocate_info<32, false>*, unsigned int,
654 Target_i386*, Output_section*, size_t, const unsigned char*,
655 const Sized_symbol<32>*, const Symbol_value<32>*,
656 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
657 section_size_type);
658
659 private:
660 // Do a TLS relocation.
661 inline void
662 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
663 size_t relnum, const elfcpp::Rel<32, false>&,
664 unsigned int r_type, const Sized_symbol<32>*,
665 const Symbol_value<32>*,
666 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
667 section_size_type);
668
669 // Do a TLS General-Dynamic to Initial-Exec transition.
670 inline void
671 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
672 const elfcpp::Rel<32, false>&, unsigned int r_type,
673 elfcpp::Elf_types<32>::Elf_Addr value,
674 unsigned char* view,
675 section_size_type view_size);
676
677 // Do a TLS General-Dynamic to Local-Exec transition.
678 inline void
679 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
680 Output_segment* tls_segment,
681 const elfcpp::Rel<32, false>&, unsigned int r_type,
682 elfcpp::Elf_types<32>::Elf_Addr value,
683 unsigned char* view,
684 section_size_type view_size);
685
686 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
687 // transition.
688 inline void
689 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
690 const elfcpp::Rel<32, false>&, unsigned int r_type,
691 elfcpp::Elf_types<32>::Elf_Addr value,
692 unsigned char* view,
693 section_size_type view_size);
694
695 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
696 // transition.
697 inline void
698 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
699 Output_segment* tls_segment,
700 const elfcpp::Rel<32, false>&, unsigned int r_type,
701 elfcpp::Elf_types<32>::Elf_Addr value,
702 unsigned char* view,
703 section_size_type view_size);
704
705 // Do a TLS Local-Dynamic to Local-Exec transition.
706 inline void
707 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
708 Output_segment* tls_segment,
709 const elfcpp::Rel<32, false>&, unsigned int r_type,
710 elfcpp::Elf_types<32>::Elf_Addr value,
711 unsigned char* view,
712 section_size_type view_size);
713
714 // Do a TLS Initial-Exec to Local-Exec transition.
715 static inline void
716 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
717 Output_segment* tls_segment,
718 const elfcpp::Rel<32, false>&, unsigned int r_type,
719 elfcpp::Elf_types<32>::Elf_Addr value,
720 unsigned char* view,
721 section_size_type view_size);
722
723 // We need to keep track of which type of local dynamic relocation
724 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
725 enum Local_dynamic_type
726 {
727 LOCAL_DYNAMIC_NONE,
728 LOCAL_DYNAMIC_SUN,
729 LOCAL_DYNAMIC_GNU
730 };
731
732 // This is set if we should skip the next reloc, which should be a
733 // PLT32 reloc against ___tls_get_addr.
734 bool skip_call_tls_get_addr_;
735 // The type of local dynamic relocation we have seen in the section
736 // being relocated, if any.
737 Local_dynamic_type local_dynamic_type_;
738 };
739
740 // A class for inquiring about properties of a relocation,
741 // used while scanning relocs during a relocatable link and
742 // garbage collection.
743 class Classify_reloc :
744 public gold::Default_classify_reloc<elfcpp::SHT_REL, 32, false>
745 {
746 public:
747 typedef Reloc_types<elfcpp::SHT_REL, 32, false>::Reloc Reltype;
748
749 // Return the explicit addend of the relocation (return 0 for SHT_REL).
750 static elfcpp::Elf_types<32>::Elf_Swxword
751 get_r_addend(const Reltype*)
752 { return 0; }
753
754 // Return the size of the addend of the relocation (only used for SHT_REL).
755 static unsigned int
756 get_size_for_reloc(unsigned int, Relobj*);
757 };
758
759 // Adjust TLS relocation type based on the options and whether this
760 // is a local symbol.
761 static tls::Tls_optimization
762 optimize_tls_reloc(bool is_final, int r_type);
763
764 // Check if relocation against this symbol is a candidate for
765 // conversion from
766 // mov foo@GOT(%reg), %reg
767 // to
768 // lea foo@GOTOFF(%reg), %reg.
769 static bool
770 can_convert_mov_to_lea(const Symbol* gsym)
771 {
772 gold_assert(gsym != NULL);
773 return (gsym->type() != elfcpp::STT_GNU_IFUNC
774 && !gsym->is_undefined ()
775 && !gsym->is_from_dynobj()
776 && !gsym->is_preemptible()
777 && (!parameters->options().shared()
778 || (gsym->visibility() != elfcpp::STV_DEFAULT
779 && gsym->visibility() != elfcpp::STV_PROTECTED)
780 || parameters->options().Bsymbolic())
781 && strcmp(gsym->name(), "_DYNAMIC") != 0);
782 }
783
784 // Get the GOT section, creating it if necessary.
785 Output_data_got<32, false>*
786 got_section(Symbol_table*, Layout*);
787
788 // Get the GOT PLT section.
789 Output_data_got_plt_i386*
790 got_plt_section() const
791 {
792 gold_assert(this->got_plt_ != NULL);
793 return this->got_plt_;
794 }
795
796 // Get the GOT section for TLSDESC entries.
797 Output_data_got<32, false>*
798 got_tlsdesc_section() const
799 {
800 gold_assert(this->got_tlsdesc_ != NULL);
801 return this->got_tlsdesc_;
802 }
803
804 // Create the PLT section.
805 void
806 make_plt_section(Symbol_table* symtab, Layout* layout);
807
808 // Create a PLT entry for a global symbol.
809 void
810 make_plt_entry(Symbol_table*, Layout*, Symbol*);
811
812 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
813 void
814 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
815 Sized_relobj_file<32, false>* relobj,
816 unsigned int local_sym_index);
817
818 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
819 void
820 define_tls_base_symbol(Symbol_table*, Layout*);
821
822 // Create a GOT entry for the TLS module index.
823 unsigned int
824 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
825 Sized_relobj_file<32, false>* object);
826
827 // Get the PLT section.
828 Output_data_plt_i386*
829 plt_section() const
830 {
831 gold_assert(this->plt_ != NULL);
832 return this->plt_;
833 }
834
835 // Get the dynamic reloc section, creating it if necessary.
836 Reloc_section*
837 rel_dyn_section(Layout*);
838
839 // Get the section to use for TLS_DESC relocations.
840 Reloc_section*
841 rel_tls_desc_section(Layout*) const;
842
843 // Get the section to use for IRELATIVE relocations.
844 Reloc_section*
845 rel_irelative_section(Layout*);
846
847 // Add a potential copy relocation.
848 void
849 copy_reloc(Symbol_table* symtab, Layout* layout,
850 Sized_relobj_file<32, false>* object,
851 unsigned int shndx, Output_section* output_section,
852 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
853 {
854 unsigned int r_type = elfcpp::elf_r_type<32>(reloc.get_r_info());
855 this->copy_relocs_.copy_reloc(symtab, layout,
856 symtab->get_sized_symbol<32>(sym),
857 object, shndx, output_section,
858 r_type, reloc.get_r_offset(), 0,
859 this->rel_dyn_section(layout));
860 }
861
862 // Information about this specific target which we pass to the
863 // general Target structure.
864 static const Target::Target_info i386_info;
865
866 // The types of GOT entries needed for this platform.
867 // These values are exposed to the ABI in an incremental link.
868 // Do not renumber existing values without changing the version
869 // number of the .gnu_incremental_inputs section.
870 enum Got_type
871 {
872 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
873 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
874 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
875 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
876 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
877 };
878
879 // The GOT section.
880 Output_data_got<32, false>* got_;
881 // The PLT section.
882 Output_data_plt_i386* plt_;
883 // The GOT PLT section.
884 Output_data_got_plt_i386* got_plt_;
885 // The GOT section for IRELATIVE relocations.
886 Output_data_space* got_irelative_;
887 // The GOT section for TLSDESC relocations.
888 Output_data_got<32, false>* got_tlsdesc_;
889 // The _GLOBAL_OFFSET_TABLE_ symbol.
890 Symbol* global_offset_table_;
891 // The dynamic reloc section.
892 Reloc_section* rel_dyn_;
893 // The section to use for IRELATIVE relocs.
894 Reloc_section* rel_irelative_;
895 // Relocs saved to avoid a COPY reloc.
896 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
897 // Offset of the GOT entry for the TLS module index.
898 unsigned int got_mod_index_offset_;
899 // True if the _TLS_MODULE_BASE_ symbol has been defined.
900 bool tls_base_symbol_defined_;
901 };
902
903 const Target::Target_info Target_i386::i386_info =
904 {
905 32, // size
906 false, // is_big_endian
907 elfcpp::EM_386, // machine_code
908 false, // has_make_symbol
909 false, // has_resolve
910 true, // has_code_fill
911 true, // is_default_stack_executable
912 true, // can_icf_inline_merge_sections
913 '\0', // wrap_char
914 "/usr/lib/libc.so.1", // dynamic_linker
915 0x08048000, // default_text_segment_address
916 0x1000, // abi_pagesize (overridable by -z max-page-size)
917 0x1000, // common_pagesize (overridable by -z common-page-size)
918 false, // isolate_execinstr
919 0, // rosegment_gap
920 elfcpp::SHN_UNDEF, // small_common_shndx
921 elfcpp::SHN_UNDEF, // large_common_shndx
922 0, // small_common_section_flags
923 0, // large_common_section_flags
924 NULL, // attributes_section
925 NULL, // attributes_vendor
926 "_start", // entry_symbol_name
927 32, // hash_entry_size
928 elfcpp::SHT_PROGBITS, // unwind_section_type
929 };
930
931 // Get the GOT section, creating it if necessary.
932
933 Output_data_got<32, false>*
934 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
935 {
936 if (this->got_ == NULL)
937 {
938 gold_assert(symtab != NULL && layout != NULL);
939
940 this->got_ = new Output_data_got<32, false>();
941
942 // When using -z now, we can treat .got.plt as a relro section.
943 // Without -z now, it is modified after program startup by lazy
944 // PLT relocations.
945 bool is_got_plt_relro = parameters->options().now();
946 Output_section_order got_order = (is_got_plt_relro
947 ? ORDER_RELRO
948 : ORDER_RELRO_LAST);
949 Output_section_order got_plt_order = (is_got_plt_relro
950 ? ORDER_RELRO
951 : ORDER_NON_RELRO_FIRST);
952
953 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
954 (elfcpp::SHF_ALLOC
955 | elfcpp::SHF_WRITE),
956 this->got_, got_order, true);
957
958 this->got_plt_ = new Output_data_got_plt_i386(layout);
959 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
960 (elfcpp::SHF_ALLOC
961 | elfcpp::SHF_WRITE),
962 this->got_plt_, got_plt_order,
963 is_got_plt_relro);
964
965 // The first three entries are reserved.
966 this->got_plt_->set_current_data_size(3 * 4);
967
968 if (!is_got_plt_relro)
969 {
970 // Those bytes can go into the relro segment.
971 layout->increase_relro(3 * 4);
972 }
973
974 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
975 this->global_offset_table_ =
976 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
977 Symbol_table::PREDEFINED,
978 this->got_plt_,
979 0, 0, elfcpp::STT_OBJECT,
980 elfcpp::STB_LOCAL,
981 elfcpp::STV_HIDDEN, 0,
982 false, false);
983
984 // If there are any IRELATIVE relocations, they get GOT entries
985 // in .got.plt after the jump slot relocations.
986 this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT");
987 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
988 (elfcpp::SHF_ALLOC
989 | elfcpp::SHF_WRITE),
990 this->got_irelative_,
991 got_plt_order, is_got_plt_relro);
992
993 // If there are any TLSDESC relocations, they get GOT entries in
994 // .got.plt after the jump slot entries.
995 this->got_tlsdesc_ = new Output_data_got<32, false>();
996 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
997 (elfcpp::SHF_ALLOC
998 | elfcpp::SHF_WRITE),
999 this->got_tlsdesc_,
1000 got_plt_order, is_got_plt_relro);
1001 }
1002
1003 return this->got_;
1004 }
1005
1006 // Get the dynamic reloc section, creating it if necessary.
1007
1008 Target_i386::Reloc_section*
1009 Target_i386::rel_dyn_section(Layout* layout)
1010 {
1011 if (this->rel_dyn_ == NULL)
1012 {
1013 gold_assert(layout != NULL);
1014 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
1015 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
1016 elfcpp::SHF_ALLOC, this->rel_dyn_,
1017 ORDER_DYNAMIC_RELOCS, false);
1018 }
1019 return this->rel_dyn_;
1020 }
1021
1022 // Get the section to use for IRELATIVE relocs, creating it if
1023 // necessary. These go in .rel.dyn, but only after all other dynamic
1024 // relocations. They need to follow the other dynamic relocations so
1025 // that they can refer to global variables initialized by those
1026 // relocs.
1027
1028 Target_i386::Reloc_section*
1029 Target_i386::rel_irelative_section(Layout* layout)
1030 {
1031 if (this->rel_irelative_ == NULL)
1032 {
1033 // Make sure we have already create the dynamic reloc section.
1034 this->rel_dyn_section(layout);
1035 this->rel_irelative_ = new Reloc_section(false);
1036 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
1037 elfcpp::SHF_ALLOC, this->rel_irelative_,
1038 ORDER_DYNAMIC_RELOCS, false);
1039 gold_assert(this->rel_dyn_->output_section()
1040 == this->rel_irelative_->output_section());
1041 }
1042 return this->rel_irelative_;
1043 }
1044
1045 // Write the first three reserved words of the .got.plt section.
1046 // The remainder of the section is written while writing the PLT
1047 // in Output_data_plt_i386::do_write.
1048
1049 void
1050 Output_data_got_plt_i386::do_write(Output_file* of)
1051 {
1052 // The first entry in the GOT is the address of the .dynamic section
1053 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1054 // We saved space for them when we created the section in
1055 // Target_i386::got_section.
1056 const off_t got_file_offset = this->offset();
1057 gold_assert(this->data_size() >= 12);
1058 unsigned char* const got_view = of->get_output_view(got_file_offset, 12);
1059 Output_section* dynamic = this->layout_->dynamic_section();
1060 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1061 elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr);
1062 memset(got_view + 4, 0, 8);
1063 of->write_output_view(got_file_offset, 12, got_view);
1064 }
1065
1066 // Create the PLT section. The ordinary .got section is an argument,
1067 // since we need to refer to the start. We also create our own .got
1068 // section just for PLT entries.
1069
1070 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
1071 uint64_t addralign,
1072 Output_data_got_plt_i386* got_plt,
1073 Output_data_space* got_irelative)
1074 : Output_section_data(addralign),
1075 tls_desc_rel_(NULL), irelative_rel_(NULL), got_plt_(got_plt),
1076 got_irelative_(got_irelative), count_(0), irelative_count_(0),
1077 global_ifuncs_(), local_ifuncs_()
1078 {
1079 this->rel_ = new Reloc_section(false);
1080 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1081 elfcpp::SHF_ALLOC, this->rel_,
1082 ORDER_DYNAMIC_PLT_RELOCS, false);
1083 }
1084
1085 void
1086 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
1087 {
1088 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
1089 // linker, and so do we.
1090 os->set_entsize(4);
1091 }
1092
1093 // Add an entry to the PLT.
1094
1095 void
1096 Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
1097 Symbol* gsym)
1098 {
1099 gold_assert(!gsym->has_plt_offset());
1100
1101 // Every PLT entry needs a reloc.
1102 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1103 && gsym->can_use_relative_reloc(false))
1104 {
1105 gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size());
1106 ++this->irelative_count_;
1107 section_offset_type got_offset =
1108 this->got_irelative_->current_data_size();
1109 this->got_irelative_->set_current_data_size(got_offset + 4);
1110 Reloc_section* rel = this->rel_irelative(symtab, layout);
1111 rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
1112 this->got_irelative_, got_offset);
1113 struct Global_ifunc gi;
1114 gi.sym = gsym;
1115 gi.got_offset = got_offset;
1116 this->global_ifuncs_.push_back(gi);
1117 }
1118 else
1119 {
1120 // When setting the PLT offset we skip the initial reserved PLT
1121 // entry.
1122 gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size());
1123
1124 ++this->count_;
1125
1126 section_offset_type got_offset = this->got_plt_->current_data_size();
1127
1128 // Every PLT entry needs a GOT entry which points back to the
1129 // PLT entry (this will be changed by the dynamic linker,
1130 // normally lazily when the function is called).
1131 this->got_plt_->set_current_data_size(got_offset + 4);
1132
1133 gsym->set_needs_dynsym_entry();
1134 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
1135 got_offset);
1136 }
1137
1138 // Note that we don't need to save the symbol. The contents of the
1139 // PLT are independent of which symbols are used. The symbols only
1140 // appear in the relocations.
1141 }
1142
1143 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1144 // the PLT offset.
1145
1146 unsigned int
1147 Output_data_plt_i386::add_local_ifunc_entry(
1148 Symbol_table* symtab,
1149 Layout* layout,
1150 Sized_relobj_file<32, false>* relobj,
1151 unsigned int local_sym_index)
1152 {
1153 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1154 ++this->irelative_count_;
1155
1156 section_offset_type got_offset = this->got_irelative_->current_data_size();
1157
1158 // Every PLT entry needs a GOT entry which points back to the PLT
1159 // entry.
1160 this->got_irelative_->set_current_data_size(got_offset + 4);
1161
1162 // Every PLT entry needs a reloc.
1163 Reloc_section* rel = this->rel_irelative(symtab, layout);
1164 rel->add_symbolless_local_addend(relobj, local_sym_index,
1165 elfcpp::R_386_IRELATIVE,
1166 this->got_irelative_, got_offset);
1167
1168 struct Local_ifunc li;
1169 li.object = relobj;
1170 li.local_sym_index = local_sym_index;
1171 li.got_offset = got_offset;
1172 this->local_ifuncs_.push_back(li);
1173
1174 return plt_offset;
1175 }
1176
1177 // Return where the TLS_DESC relocations should go, creating it if
1178 // necessary. These follow the JUMP_SLOT relocations.
1179
1180 Output_data_plt_i386::Reloc_section*
1181 Output_data_plt_i386::rel_tls_desc(Layout* layout)
1182 {
1183 if (this->tls_desc_rel_ == NULL)
1184 {
1185 this->tls_desc_rel_ = new Reloc_section(false);
1186 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1187 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
1188 ORDER_DYNAMIC_PLT_RELOCS, false);
1189 gold_assert(this->tls_desc_rel_->output_section()
1190 == this->rel_->output_section());
1191 }
1192 return this->tls_desc_rel_;
1193 }
1194
1195 // Return where the IRELATIVE relocations should go in the PLT. These
1196 // follow the JUMP_SLOT and TLS_DESC relocations.
1197
1198 Output_data_plt_i386::Reloc_section*
1199 Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
1200 {
1201 if (this->irelative_rel_ == NULL)
1202 {
1203 // Make sure we have a place for the TLS_DESC relocations, in
1204 // case we see any later on.
1205 this->rel_tls_desc(layout);
1206 this->irelative_rel_ = new Reloc_section(false);
1207 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1208 elfcpp::SHF_ALLOC, this->irelative_rel_,
1209 ORDER_DYNAMIC_PLT_RELOCS, false);
1210 gold_assert(this->irelative_rel_->output_section()
1211 == this->rel_->output_section());
1212
1213 if (parameters->doing_static_link())
1214 {
1215 // A statically linked executable will only have a .rel.plt
1216 // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
1217 // symbols. The library will use these symbols to locate
1218 // the IRELATIVE relocs at program startup time.
1219 symtab->define_in_output_data("__rel_iplt_start", NULL,
1220 Symbol_table::PREDEFINED,
1221 this->irelative_rel_, 0, 0,
1222 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1223 elfcpp::STV_HIDDEN, 0, false, true);
1224 symtab->define_in_output_data("__rel_iplt_end", NULL,
1225 Symbol_table::PREDEFINED,
1226 this->irelative_rel_, 0, 0,
1227 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1228 elfcpp::STV_HIDDEN, 0, true, true);
1229 }
1230 }
1231 return this->irelative_rel_;
1232 }
1233
1234 // Return the PLT address to use for a global symbol.
1235
1236 uint64_t
1237 Output_data_plt_i386::address_for_global(const Symbol* gsym)
1238 {
1239 uint64_t offset = 0;
1240 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1241 && gsym->can_use_relative_reloc(false))
1242 offset = (this->count_ + 1) * this->get_plt_entry_size();
1243 return this->address() + offset + gsym->plt_offset();
1244 }
1245
1246 // Return the PLT address to use for a local symbol. These are always
1247 // IRELATIVE relocs.
1248
1249 uint64_t
1250 Output_data_plt_i386::address_for_local(const Relobj* object,
1251 unsigned int r_sym)
1252 {
1253 return (this->address()
1254 + (this->count_ + 1) * this->get_plt_entry_size()
1255 + object->local_plt_offset(r_sym));
1256 }
1257
1258 // The first entry in the PLT for an executable.
1259
1260 const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] =
1261 {
1262 0xff, 0x35, // pushl contents of memory address
1263 0, 0, 0, 0, // replaced with address of .got + 4
1264 0xff, 0x25, // jmp indirect
1265 0, 0, 0, 0, // replaced with address of .got + 8
1266 0, 0, 0, 0 // unused
1267 };
1268
1269 void
1270 Output_data_plt_i386_exec::do_fill_first_plt_entry(
1271 unsigned char* pov,
1272 elfcpp::Elf_types<32>::Elf_Addr got_address)
1273 {
1274 memcpy(pov, first_plt_entry, plt_entry_size);
1275 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
1276 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
1277 }
1278
1279 // The first entry in the PLT for a shared object.
1280
1281 const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] =
1282 {
1283 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
1284 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
1285 0, 0, 0, 0 // unused
1286 };
1287
1288 void
1289 Output_data_plt_i386_dyn::do_fill_first_plt_entry(
1290 unsigned char* pov,
1291 elfcpp::Elf_types<32>::Elf_Addr)
1292 {
1293 memcpy(pov, first_plt_entry, plt_entry_size);
1294 }
1295
1296 // Subsequent entries in the PLT for an executable.
1297
1298 const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] =
1299 {
1300 0xff, 0x25, // jmp indirect
1301 0, 0, 0, 0, // replaced with address of symbol in .got
1302 0x68, // pushl immediate
1303 0, 0, 0, 0, // replaced with offset into relocation table
1304 0xe9, // jmp relative
1305 0, 0, 0, 0 // replaced with offset to start of .plt
1306 };
1307
1308 unsigned int
1309 Output_data_plt_i386_exec::do_fill_plt_entry(
1310 unsigned char* pov,
1311 elfcpp::Elf_types<32>::Elf_Addr got_address,
1312 unsigned int got_offset,
1313 unsigned int plt_offset,
1314 unsigned int plt_rel_offset)
1315 {
1316 memcpy(pov, plt_entry, plt_entry_size);
1317 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1318 got_address + got_offset);
1319 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1320 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1321 return 6;
1322 }
1323
1324 // Subsequent entries in the PLT for a shared object.
1325
1326 const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] =
1327 {
1328 0xff, 0xa3, // jmp *offset(%ebx)
1329 0, 0, 0, 0, // replaced with offset of symbol in .got
1330 0x68, // pushl immediate
1331 0, 0, 0, 0, // replaced with offset into relocation table
1332 0xe9, // jmp relative
1333 0, 0, 0, 0 // replaced with offset to start of .plt
1334 };
1335
1336 unsigned int
1337 Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov,
1338 elfcpp::Elf_types<32>::Elf_Addr,
1339 unsigned int got_offset,
1340 unsigned int plt_offset,
1341 unsigned int plt_rel_offset)
1342 {
1343 memcpy(pov, plt_entry, plt_entry_size);
1344 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
1345 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1346 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1347 return 6;
1348 }
1349
1350 // The .eh_frame unwind information for the PLT.
1351
1352 const unsigned char
1353 Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1354 {
1355 1, // CIE version.
1356 'z', // Augmentation: augmentation size included.
1357 'R', // Augmentation: FDE encoding included.
1358 '\0', // End of augmentation string.
1359 1, // Code alignment factor.
1360 0x7c, // Data alignment factor.
1361 8, // Return address column.
1362 1, // Augmentation size.
1363 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1364 | elfcpp::DW_EH_PE_sdata4),
1365 elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
1366 elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
1367 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1368 elfcpp::DW_CFA_nop
1369 };
1370
1371 const unsigned char
1372 Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1373 {
1374 0, 0, 0, 0, // Replaced with offset to .plt.
1375 0, 0, 0, 0, // Replaced with size of .plt.
1376 0, // Augmentation size.
1377 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
1378 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1379 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
1380 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1381 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1382 11, // Block length.
1383 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
1384 elfcpp::DW_OP_breg8, 0, // Push %eip.
1385 elfcpp::DW_OP_lit15, // Push 0xf.
1386 elfcpp::DW_OP_and, // & (%eip & 0xf).
1387 elfcpp::DW_OP_lit11, // Push 0xb.
1388 elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
1389 elfcpp::DW_OP_lit2, // Push 2.
1390 elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
1391 elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4
1392 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1393 elfcpp::DW_CFA_nop,
1394 elfcpp::DW_CFA_nop,
1395 elfcpp::DW_CFA_nop
1396 };
1397
1398 // Write out the PLT. This uses the hand-coded instructions above,
1399 // and adjusts them as needed. This is all specified by the i386 ELF
1400 // Processor Supplement.
1401
1402 void
1403 Output_data_plt_i386::do_write(Output_file* of)
1404 {
1405 const off_t offset = this->offset();
1406 const section_size_type oview_size =
1407 convert_to_section_size_type(this->data_size());
1408 unsigned char* const oview = of->get_output_view(offset, oview_size);
1409
1410 const off_t got_file_offset = this->got_plt_->offset();
1411 gold_assert(parameters->incremental_update()
1412 || (got_file_offset + this->got_plt_->data_size()
1413 == this->got_irelative_->offset()));
1414 const section_size_type got_size =
1415 convert_to_section_size_type(this->got_plt_->data_size()
1416 + this->got_irelative_->data_size());
1417
1418 unsigned char* const got_view = of->get_output_view(got_file_offset,
1419 got_size);
1420
1421 unsigned char* pov = oview;
1422
1423 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
1424 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
1425
1426 this->fill_first_plt_entry(pov, got_address);
1427 pov += this->get_plt_entry_size();
1428
1429 // The first three entries in the GOT are reserved, and are written
1430 // by Output_data_got_plt_i386::do_write.
1431 unsigned char* got_pov = got_view + 12;
1432
1433 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
1434
1435 unsigned int plt_offset = this->get_plt_entry_size();
1436 unsigned int plt_rel_offset = 0;
1437 unsigned int got_offset = 12;
1438 const unsigned int count = this->count_ + this->irelative_count_;
1439 for (unsigned int i = 0;
1440 i < count;
1441 ++i,
1442 pov += this->get_plt_entry_size(),
1443 got_pov += 4,
1444 plt_offset += this->get_plt_entry_size(),
1445 plt_rel_offset += rel_size,
1446 got_offset += 4)
1447 {
1448 // Set and adjust the PLT entry itself.
1449 unsigned int lazy_offset = this->fill_plt_entry(pov,
1450 got_address,
1451 got_offset,
1452 plt_offset,
1453 plt_rel_offset);
1454
1455 // Set the entry in the GOT.
1456 elfcpp::Swap<32, false>::writeval(got_pov,
1457 plt_address + plt_offset + lazy_offset);
1458 }
1459
1460 // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
1461 // the GOT to point to the actual symbol value, rather than point to
1462 // the PLT entry. That will let the dynamic linker call the right
1463 // function when resolving IRELATIVE relocations.
1464 unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
1465 for (std::vector<Global_ifunc>::const_iterator p =
1466 this->global_ifuncs_.begin();
1467 p != this->global_ifuncs_.end();
1468 ++p)
1469 {
1470 const Sized_symbol<32>* ssym =
1471 static_cast<const Sized_symbol<32>*>(p->sym);
1472 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1473 ssym->value());
1474 }
1475
1476 for (std::vector<Local_ifunc>::const_iterator p =
1477 this->local_ifuncs_.begin();
1478 p != this->local_ifuncs_.end();
1479 ++p)
1480 {
1481 const Symbol_value<32>* psymval =
1482 p->object->local_symbol(p->local_sym_index);
1483 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1484 psymval->value(p->object, 0));
1485 }
1486
1487 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1488 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1489
1490 of->write_output_view(offset, oview_size, oview);
1491 of->write_output_view(got_file_offset, got_size, got_view);
1492 }
1493
1494 // Create the PLT section.
1495
1496 void
1497 Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
1498 {
1499 if (this->plt_ == NULL)
1500 {
1501 // Create the GOT sections first.
1502 this->got_section(symtab, layout);
1503
1504 const bool dyn = parameters->options().output_is_position_independent();
1505 this->plt_ = this->make_data_plt(layout,
1506 this->got_plt_,
1507 this->got_irelative_,
1508 dyn);
1509
1510 // Add unwind information if requested.
1511 if (parameters->options().ld_generated_unwind_info())
1512 this->plt_->add_eh_frame(layout);
1513
1514 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1515 (elfcpp::SHF_ALLOC
1516 | elfcpp::SHF_EXECINSTR),
1517 this->plt_, ORDER_PLT, false);
1518
1519 // Make the sh_info field of .rel.plt point to .plt.
1520 Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
1521 rel_plt_os->set_info_section(this->plt_->output_section());
1522 }
1523 }
1524
1525 // Create a PLT entry for a global symbol.
1526
1527 void
1528 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
1529 {
1530 if (gsym->has_plt_offset())
1531 return;
1532 if (this->plt_ == NULL)
1533 this->make_plt_section(symtab, layout);
1534 this->plt_->add_entry(symtab, layout, gsym);
1535 }
1536
1537 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1538
1539 void
1540 Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1541 Sized_relobj_file<32, false>* relobj,
1542 unsigned int local_sym_index)
1543 {
1544 if (relobj->local_has_plt_offset(local_sym_index))
1545 return;
1546 if (this->plt_ == NULL)
1547 this->make_plt_section(symtab, layout);
1548 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1549 relobj,
1550 local_sym_index);
1551 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1552 }
1553
1554 // Return the number of entries in the PLT.
1555
1556 unsigned int
1557 Target_i386::plt_entry_count() const
1558 {
1559 if (this->plt_ == NULL)
1560 return 0;
1561 return this->plt_->entry_count();
1562 }
1563
1564 // Return the offset of the first non-reserved PLT entry.
1565
1566 unsigned int
1567 Target_i386::first_plt_entry_offset() const
1568 {
1569 if (this->plt_ == NULL)
1570 return 0;
1571 return this->plt_->first_plt_entry_offset();
1572 }
1573
1574 // Return the size of each PLT entry.
1575
1576 unsigned int
1577 Target_i386::plt_entry_size() const
1578 {
1579 if (this->plt_ == NULL)
1580 return 0;
1581 return this->plt_->get_plt_entry_size();
1582 }
1583
1584 // Get the section to use for TLS_DESC relocations.
1585
1586 Target_i386::Reloc_section*
1587 Target_i386::rel_tls_desc_section(Layout* layout) const
1588 {
1589 return this->plt_section()->rel_tls_desc(layout);
1590 }
1591
1592 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1593
1594 void
1595 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1596 {
1597 if (this->tls_base_symbol_defined_)
1598 return;
1599
1600 Output_segment* tls_segment = layout->tls_segment();
1601 if (tls_segment != NULL)
1602 {
1603 bool is_exec = parameters->options().output_is_executable();
1604 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1605 Symbol_table::PREDEFINED,
1606 tls_segment, 0, 0,
1607 elfcpp::STT_TLS,
1608 elfcpp::STB_LOCAL,
1609 elfcpp::STV_HIDDEN, 0,
1610 (is_exec
1611 ? Symbol::SEGMENT_END
1612 : Symbol::SEGMENT_START),
1613 true);
1614 }
1615 this->tls_base_symbol_defined_ = true;
1616 }
1617
1618 // Create a GOT entry for the TLS module index.
1619
1620 unsigned int
1621 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1622 Sized_relobj_file<32, false>* object)
1623 {
1624 if (this->got_mod_index_offset_ == -1U)
1625 {
1626 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1627 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1628 Output_data_got<32, false>* got = this->got_section(symtab, layout);
1629 unsigned int got_offset = got->add_constant(0);
1630 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
1631 got_offset);
1632 got->add_constant(0);
1633 this->got_mod_index_offset_ = got_offset;
1634 }
1635 return this->got_mod_index_offset_;
1636 }
1637
1638 // Optimize the TLS relocation type based on what we know about the
1639 // symbol. IS_FINAL is true if the final address of this symbol is
1640 // known at link time.
1641
1642 tls::Tls_optimization
1643 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
1644 {
1645 // If we are generating a shared library, then we can't do anything
1646 // in the linker.
1647 if (parameters->options().shared())
1648 return tls::TLSOPT_NONE;
1649
1650 switch (r_type)
1651 {
1652 case elfcpp::R_386_TLS_GD:
1653 case elfcpp::R_386_TLS_GOTDESC:
1654 case elfcpp::R_386_TLS_DESC_CALL:
1655 // These are General-Dynamic which permits fully general TLS
1656 // access. Since we know that we are generating an executable,
1657 // we can convert this to Initial-Exec. If we also know that
1658 // this is a local symbol, we can further switch to Local-Exec.
1659 if (is_final)
1660 return tls::TLSOPT_TO_LE;
1661 return tls::TLSOPT_TO_IE;
1662
1663 case elfcpp::R_386_TLS_LDM:
1664 // This is Local-Dynamic, which refers to a local symbol in the
1665 // dynamic TLS block. Since we know that we generating an
1666 // executable, we can switch to Local-Exec.
1667 return tls::TLSOPT_TO_LE;
1668
1669 case elfcpp::R_386_TLS_LDO_32:
1670 // Another type of Local-Dynamic relocation.
1671 return tls::TLSOPT_TO_LE;
1672
1673 case elfcpp::R_386_TLS_IE:
1674 case elfcpp::R_386_TLS_GOTIE:
1675 case elfcpp::R_386_TLS_IE_32:
1676 // These are Initial-Exec relocs which get the thread offset
1677 // from the GOT. If we know that we are linking against the
1678 // local symbol, we can switch to Local-Exec, which links the
1679 // thread offset into the instruction.
1680 if (is_final)
1681 return tls::TLSOPT_TO_LE;
1682 return tls::TLSOPT_NONE;
1683
1684 case elfcpp::R_386_TLS_LE:
1685 case elfcpp::R_386_TLS_LE_32:
1686 // When we already have Local-Exec, there is nothing further we
1687 // can do.
1688 return tls::TLSOPT_NONE;
1689
1690 default:
1691 gold_unreachable();
1692 }
1693 }
1694
1695 // Get the Reference_flags for a particular relocation.
1696
1697 int
1698 Target_i386::Scan::get_reference_flags(unsigned int r_type)
1699 {
1700 switch (r_type)
1701 {
1702 case elfcpp::R_386_NONE:
1703 case elfcpp::R_386_GNU_VTINHERIT:
1704 case elfcpp::R_386_GNU_VTENTRY:
1705 case elfcpp::R_386_GOTPC:
1706 // No symbol reference.
1707 return 0;
1708
1709 case elfcpp::R_386_32:
1710 case elfcpp::R_386_16:
1711 case elfcpp::R_386_8:
1712 return Symbol::ABSOLUTE_REF;
1713
1714 case elfcpp::R_386_PC32:
1715 case elfcpp::R_386_PC16:
1716 case elfcpp::R_386_PC8:
1717 case elfcpp::R_386_GOTOFF:
1718 return Symbol::RELATIVE_REF;
1719
1720 case elfcpp::R_386_PLT32:
1721 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1722
1723 case elfcpp::R_386_GOT32:
1724 case elfcpp::R_386_GOT32X:
1725 // Absolute in GOT.
1726 return Symbol::ABSOLUTE_REF;
1727
1728 case elfcpp::R_386_TLS_GD: // Global-dynamic
1729 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1730 case elfcpp::R_386_TLS_DESC_CALL:
1731 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1732 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1733 case elfcpp::R_386_TLS_IE: // Initial-exec
1734 case elfcpp::R_386_TLS_IE_32:
1735 case elfcpp::R_386_TLS_GOTIE:
1736 case elfcpp::R_386_TLS_LE: // Local-exec
1737 case elfcpp::R_386_TLS_LE_32:
1738 return Symbol::TLS_REF;
1739
1740 case elfcpp::R_386_COPY:
1741 case elfcpp::R_386_GLOB_DAT:
1742 case elfcpp::R_386_JUMP_SLOT:
1743 case elfcpp::R_386_RELATIVE:
1744 case elfcpp::R_386_IRELATIVE:
1745 case elfcpp::R_386_TLS_TPOFF:
1746 case elfcpp::R_386_TLS_DTPMOD32:
1747 case elfcpp::R_386_TLS_DTPOFF32:
1748 case elfcpp::R_386_TLS_TPOFF32:
1749 case elfcpp::R_386_TLS_DESC:
1750 case elfcpp::R_386_32PLT:
1751 case elfcpp::R_386_TLS_GD_32:
1752 case elfcpp::R_386_TLS_GD_PUSH:
1753 case elfcpp::R_386_TLS_GD_CALL:
1754 case elfcpp::R_386_TLS_GD_POP:
1755 case elfcpp::R_386_TLS_LDM_32:
1756 case elfcpp::R_386_TLS_LDM_PUSH:
1757 case elfcpp::R_386_TLS_LDM_CALL:
1758 case elfcpp::R_386_TLS_LDM_POP:
1759 case elfcpp::R_386_USED_BY_INTEL_200:
1760 default:
1761 // Not expected. We will give an error later.
1762 return 0;
1763 }
1764 }
1765
1766 // Report an unsupported relocation against a local symbol.
1767
1768 void
1769 Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
1770 unsigned int r_type)
1771 {
1772 gold_error(_("%s: unsupported reloc %u against local symbol"),
1773 object->name().c_str(), r_type);
1774 }
1775
1776 // Return whether we need to make a PLT entry for a relocation of a
1777 // given type against a STT_GNU_IFUNC symbol.
1778
1779 bool
1780 Target_i386::Scan::reloc_needs_plt_for_ifunc(
1781 Sized_relobj_file<32, false>* object,
1782 unsigned int r_type)
1783 {
1784 int flags = Scan::get_reference_flags(r_type);
1785 if (flags & Symbol::TLS_REF)
1786 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1787 object->name().c_str(), r_type);
1788 return flags != 0;
1789 }
1790
1791 // Scan a relocation for a local symbol.
1792
1793 inline void
1794 Target_i386::Scan::local(Symbol_table* symtab,
1795 Layout* layout,
1796 Target_i386* target,
1797 Sized_relobj_file<32, false>* object,
1798 unsigned int data_shndx,
1799 Output_section* output_section,
1800 const elfcpp::Rel<32, false>& reloc,
1801 unsigned int r_type,
1802 const elfcpp::Sym<32, false>& lsym,
1803 bool is_discarded)
1804 {
1805 if (is_discarded)
1806 return;
1807
1808 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1809 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1810 && this->reloc_needs_plt_for_ifunc(object, r_type))
1811 {
1812 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1813 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1814 }
1815
1816 switch (r_type)
1817 {
1818 case elfcpp::R_386_NONE:
1819 case elfcpp::R_386_GNU_VTINHERIT:
1820 case elfcpp::R_386_GNU_VTENTRY:
1821 break;
1822
1823 case elfcpp::R_386_32:
1824 // If building a shared library (or a position-independent
1825 // executable), we need to create a dynamic relocation for
1826 // this location. The relocation applied at link time will
1827 // apply the link-time value, so we flag the location with
1828 // an R_386_RELATIVE relocation so the dynamic loader can
1829 // relocate it easily.
1830 if (parameters->options().output_is_position_independent())
1831 {
1832 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1833 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1834 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1835 output_section, data_shndx,
1836 reloc.get_r_offset());
1837 }
1838 break;
1839
1840 case elfcpp::R_386_16:
1841 case elfcpp::R_386_8:
1842 // If building a shared library (or a position-independent
1843 // executable), we need to create a dynamic relocation for
1844 // this location. Because the addend needs to remain in the
1845 // data section, we need to be careful not to apply this
1846 // relocation statically.
1847 if (parameters->options().output_is_position_independent())
1848 {
1849 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1850 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1851 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1852 rel_dyn->add_local(object, r_sym, r_type, output_section,
1853 data_shndx, reloc.get_r_offset());
1854 else
1855 {
1856 gold_assert(lsym.get_st_value() == 0);
1857 unsigned int shndx = lsym.get_st_shndx();
1858 bool is_ordinary;
1859 shndx = object->adjust_sym_shndx(r_sym, shndx,
1860 &is_ordinary);
1861 if (!is_ordinary)
1862 object->error(_("section symbol %u has bad shndx %u"),
1863 r_sym, shndx);
1864 else
1865 rel_dyn->add_local_section(object, shndx,
1866 r_type, output_section,
1867 data_shndx, reloc.get_r_offset());
1868 }
1869 }
1870 break;
1871
1872 case elfcpp::R_386_PC32:
1873 case elfcpp::R_386_PC16:
1874 case elfcpp::R_386_PC8:
1875 break;
1876
1877 case elfcpp::R_386_PLT32:
1878 // Since we know this is a local symbol, we can handle this as a
1879 // PC32 reloc.
1880 break;
1881
1882 case elfcpp::R_386_GOTOFF:
1883 case elfcpp::R_386_GOTPC:
1884 // We need a GOT section.
1885 target->got_section(symtab, layout);
1886 break;
1887
1888 case elfcpp::R_386_GOT32:
1889 case elfcpp::R_386_GOT32X:
1890 {
1891 // We need GOT section.
1892 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1893
1894 // If the relocation symbol isn't IFUNC,
1895 // and is local, then we will convert
1896 // mov foo@GOT(%reg), %reg
1897 // to
1898 // lea foo@GOTOFF(%reg), %reg
1899 // in Relocate::relocate.
1900 if (reloc.get_r_offset() >= 2
1901 && lsym.get_st_type() != elfcpp::STT_GNU_IFUNC)
1902 {
1903 section_size_type stype;
1904 const unsigned char* view = object->section_contents(data_shndx,
1905 &stype, true);
1906 if (view[reloc.get_r_offset() - 2] == 0x8b)
1907 break;
1908 }
1909
1910 // Otherwise, the symbol requires a GOT entry.
1911 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1912
1913 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1914 // lets function pointers compare correctly with shared
1915 // libraries. Otherwise we would need an IRELATIVE reloc.
1916 bool is_new;
1917 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1918 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1919 else
1920 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1921 if (is_new)
1922 {
1923 // If we are generating a shared object, we need to add a
1924 // dynamic RELATIVE relocation for this symbol's GOT entry.
1925 if (parameters->options().output_is_position_independent())
1926 {
1927 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1928 unsigned int got_offset =
1929 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1930 rel_dyn->add_local_relative(object, r_sym,
1931 elfcpp::R_386_RELATIVE,
1932 got, got_offset);
1933 }
1934 }
1935 }
1936 break;
1937
1938 // These are relocations which should only be seen by the
1939 // dynamic linker, and should never be seen here.
1940 case elfcpp::R_386_COPY:
1941 case elfcpp::R_386_GLOB_DAT:
1942 case elfcpp::R_386_JUMP_SLOT:
1943 case elfcpp::R_386_RELATIVE:
1944 case elfcpp::R_386_IRELATIVE:
1945 case elfcpp::R_386_TLS_TPOFF:
1946 case elfcpp::R_386_TLS_DTPMOD32:
1947 case elfcpp::R_386_TLS_DTPOFF32:
1948 case elfcpp::R_386_TLS_TPOFF32:
1949 case elfcpp::R_386_TLS_DESC:
1950 gold_error(_("%s: unexpected reloc %u in object file"),
1951 object->name().c_str(), r_type);
1952 break;
1953
1954 // These are initial TLS relocs, which are expected when
1955 // linking.
1956 case elfcpp::R_386_TLS_GD: // Global-dynamic
1957 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1958 case elfcpp::R_386_TLS_DESC_CALL:
1959 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1960 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1961 case elfcpp::R_386_TLS_IE: // Initial-exec
1962 case elfcpp::R_386_TLS_IE_32:
1963 case elfcpp::R_386_TLS_GOTIE:
1964 case elfcpp::R_386_TLS_LE: // Local-exec
1965 case elfcpp::R_386_TLS_LE_32:
1966 {
1967 bool output_is_shared = parameters->options().shared();
1968 const tls::Tls_optimization optimized_type
1969 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1970 switch (r_type)
1971 {
1972 case elfcpp::R_386_TLS_GD: // Global-dynamic
1973 if (optimized_type == tls::TLSOPT_NONE)
1974 {
1975 // Create a pair of GOT entries for the module index and
1976 // dtv-relative offset.
1977 Output_data_got<32, false>* got
1978 = target->got_section(symtab, layout);
1979 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1980 unsigned int shndx = lsym.get_st_shndx();
1981 bool is_ordinary;
1982 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1983 if (!is_ordinary)
1984 object->error(_("local symbol %u has bad shndx %u"),
1985 r_sym, shndx);
1986 else
1987 got->add_local_pair_with_rel(object, r_sym, shndx,
1988 GOT_TYPE_TLS_PAIR,
1989 target->rel_dyn_section(layout),
1990 elfcpp::R_386_TLS_DTPMOD32);
1991 }
1992 else if (optimized_type != tls::TLSOPT_TO_LE)
1993 unsupported_reloc_local(object, r_type);
1994 break;
1995
1996 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1997 target->define_tls_base_symbol(symtab, layout);
1998 if (optimized_type == tls::TLSOPT_NONE)
1999 {
2000 // Create a double GOT entry with an R_386_TLS_DESC
2001 // reloc. The R_386_TLS_DESC reloc is resolved
2002 // lazily, so the GOT entry needs to be in an area in
2003 // .got.plt, not .got. Call got_section to make sure
2004 // the section has been created.
2005 target->got_section(symtab, layout);
2006 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2007 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2008 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
2009 {
2010 unsigned int got_offset = got->add_constant(0);
2011 // The local symbol value is stored in the second
2012 // GOT entry.
2013 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
2014 // That set the GOT offset of the local symbol to
2015 // point to the second entry, but we want it to
2016 // point to the first.
2017 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
2018 got_offset);
2019 Reloc_section* rt = target->rel_tls_desc_section(layout);
2020 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
2021 }
2022 }
2023 else if (optimized_type != tls::TLSOPT_TO_LE)
2024 unsupported_reloc_local(object, r_type);
2025 break;
2026
2027 case elfcpp::R_386_TLS_DESC_CALL:
2028 break;
2029
2030 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2031 if (optimized_type == tls::TLSOPT_NONE)
2032 {
2033 // Create a GOT entry for the module index.
2034 target->got_mod_index_entry(symtab, layout, object);
2035 }
2036 else if (optimized_type != tls::TLSOPT_TO_LE)
2037 unsupported_reloc_local(object, r_type);
2038 break;
2039
2040 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2041 break;
2042
2043 case elfcpp::R_386_TLS_IE: // Initial-exec
2044 case elfcpp::R_386_TLS_IE_32:
2045 case elfcpp::R_386_TLS_GOTIE:
2046 layout->set_has_static_tls();
2047 if (optimized_type == tls::TLSOPT_NONE)
2048 {
2049 // For the R_386_TLS_IE relocation, we need to create a
2050 // dynamic relocation when building a shared library.
2051 if (r_type == elfcpp::R_386_TLS_IE
2052 && parameters->options().shared())
2053 {
2054 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2055 unsigned int r_sym
2056 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2057 rel_dyn->add_local_relative(object, r_sym,
2058 elfcpp::R_386_RELATIVE,
2059 output_section, data_shndx,
2060 reloc.get_r_offset());
2061 }
2062 // Create a GOT entry for the tp-relative offset.
2063 Output_data_got<32, false>* got
2064 = target->got_section(symtab, layout);
2065 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2066 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2067 ? elfcpp::R_386_TLS_TPOFF32
2068 : elfcpp::R_386_TLS_TPOFF);
2069 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2070 ? GOT_TYPE_TLS_OFFSET
2071 : GOT_TYPE_TLS_NOFFSET);
2072 got->add_local_with_rel(object, r_sym, got_type,
2073 target->rel_dyn_section(layout),
2074 dyn_r_type);
2075 }
2076 else if (optimized_type != tls::TLSOPT_TO_LE)
2077 unsupported_reloc_local(object, r_type);
2078 break;
2079
2080 case elfcpp::R_386_TLS_LE: // Local-exec
2081 case elfcpp::R_386_TLS_LE_32:
2082 layout->set_has_static_tls();
2083 if (output_is_shared)
2084 {
2085 // We need to create a dynamic relocation.
2086 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2087 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
2088 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2089 ? elfcpp::R_386_TLS_TPOFF32
2090 : elfcpp::R_386_TLS_TPOFF);
2091 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2092 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
2093 data_shndx, reloc.get_r_offset());
2094 }
2095 break;
2096
2097 default:
2098 gold_unreachable();
2099 }
2100 }
2101 break;
2102
2103 case elfcpp::R_386_32PLT:
2104 case elfcpp::R_386_TLS_GD_32:
2105 case elfcpp::R_386_TLS_GD_PUSH:
2106 case elfcpp::R_386_TLS_GD_CALL:
2107 case elfcpp::R_386_TLS_GD_POP:
2108 case elfcpp::R_386_TLS_LDM_32:
2109 case elfcpp::R_386_TLS_LDM_PUSH:
2110 case elfcpp::R_386_TLS_LDM_CALL:
2111 case elfcpp::R_386_TLS_LDM_POP:
2112 case elfcpp::R_386_USED_BY_INTEL_200:
2113 default:
2114 unsupported_reloc_local(object, r_type);
2115 break;
2116 }
2117 }
2118
2119 // Report an unsupported relocation against a global symbol.
2120
2121 void
2122 Target_i386::Scan::unsupported_reloc_global(
2123 Sized_relobj_file<32, false>* object,
2124 unsigned int r_type,
2125 Symbol* gsym)
2126 {
2127 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2128 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2129 }
2130
2131 inline bool
2132 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
2133 {
2134 switch (r_type)
2135 {
2136 case elfcpp::R_386_32:
2137 case elfcpp::R_386_16:
2138 case elfcpp::R_386_8:
2139 case elfcpp::R_386_GOTOFF:
2140 case elfcpp::R_386_GOT32:
2141 case elfcpp::R_386_GOT32X:
2142 {
2143 return true;
2144 }
2145 default:
2146 return false;
2147 }
2148 return false;
2149 }
2150
2151 inline bool
2152 Target_i386::Scan::local_reloc_may_be_function_pointer(
2153 Symbol_table* ,
2154 Layout* ,
2155 Target_i386* ,
2156 Sized_relobj_file<32, false>* ,
2157 unsigned int ,
2158 Output_section* ,
2159 const elfcpp::Rel<32, false>& ,
2160 unsigned int r_type,
2161 const elfcpp::Sym<32, false>&)
2162 {
2163 return possible_function_pointer_reloc(r_type);
2164 }
2165
2166 inline bool
2167 Target_i386::Scan::global_reloc_may_be_function_pointer(
2168 Symbol_table* ,
2169 Layout* ,
2170 Target_i386* ,
2171 Sized_relobj_file<32, false>* ,
2172 unsigned int ,
2173 Output_section* ,
2174 const elfcpp::Rel<32, false>& ,
2175 unsigned int r_type,
2176 Symbol*)
2177 {
2178 return possible_function_pointer_reloc(r_type);
2179 }
2180
2181 // Scan a relocation for a global symbol.
2182
2183 inline void
2184 Target_i386::Scan::global(Symbol_table* symtab,
2185 Layout* layout,
2186 Target_i386* target,
2187 Sized_relobj_file<32, false>* object,
2188 unsigned int data_shndx,
2189 Output_section* output_section,
2190 const elfcpp::Rel<32, false>& reloc,
2191 unsigned int r_type,
2192 Symbol* gsym)
2193 {
2194 // A STT_GNU_IFUNC symbol may require a PLT entry.
2195 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2196 && this->reloc_needs_plt_for_ifunc(object, r_type))
2197 target->make_plt_entry(symtab, layout, gsym);
2198
2199 switch (r_type)
2200 {
2201 case elfcpp::R_386_NONE:
2202 case elfcpp::R_386_GNU_VTINHERIT:
2203 case elfcpp::R_386_GNU_VTENTRY:
2204 break;
2205
2206 case elfcpp::R_386_32:
2207 case elfcpp::R_386_16:
2208 case elfcpp::R_386_8:
2209 {
2210 // Make a PLT entry if necessary.
2211 if (gsym->needs_plt_entry())
2212 {
2213 target->make_plt_entry(symtab, layout, gsym);
2214 // Since this is not a PC-relative relocation, we may be
2215 // taking the address of a function. In that case we need to
2216 // set the entry in the dynamic symbol table to the address of
2217 // the PLT entry.
2218 if (gsym->is_from_dynobj() && !parameters->options().shared())
2219 gsym->set_needs_dynsym_value();
2220 }
2221 // Make a dynamic relocation if necessary.
2222 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2223 {
2224 if (!parameters->options().output_is_position_independent()
2225 && gsym->may_need_copy_reloc())
2226 {
2227 target->copy_reloc(symtab, layout, object,
2228 data_shndx, output_section, gsym, reloc);
2229 }
2230 else if (r_type == elfcpp::R_386_32
2231 && gsym->type() == elfcpp::STT_GNU_IFUNC
2232 && gsym->can_use_relative_reloc(false)
2233 && !gsym->is_from_dynobj()
2234 && !gsym->is_undefined()
2235 && !gsym->is_preemptible())
2236 {
2237 // Use an IRELATIVE reloc for a locally defined
2238 // STT_GNU_IFUNC symbol. This makes a function
2239 // address in a PIE executable match the address in a
2240 // shared library that it links against.
2241 Reloc_section* rel_dyn = target->rel_irelative_section(layout);
2242 rel_dyn->add_symbolless_global_addend(gsym,
2243 elfcpp::R_386_IRELATIVE,
2244 output_section,
2245 object, data_shndx,
2246 reloc.get_r_offset());
2247 }
2248 else if (r_type == elfcpp::R_386_32
2249 && gsym->can_use_relative_reloc(false))
2250 {
2251 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2252 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2253 output_section, object,
2254 data_shndx, reloc.get_r_offset());
2255 }
2256 else
2257 {
2258 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2259 rel_dyn->add_global(gsym, r_type, output_section, object,
2260 data_shndx, reloc.get_r_offset());
2261 }
2262 }
2263 }
2264 break;
2265
2266 case elfcpp::R_386_PC32:
2267 case elfcpp::R_386_PC16:
2268 case elfcpp::R_386_PC8:
2269 {
2270 // Make a PLT entry if necessary.
2271 if (gsym->needs_plt_entry())
2272 {
2273 // These relocations are used for function calls only in
2274 // non-PIC code. For a 32-bit relocation in a shared library,
2275 // we'll need a text relocation anyway, so we can skip the
2276 // PLT entry and let the dynamic linker bind the call directly
2277 // to the target. For smaller relocations, we should use a
2278 // PLT entry to ensure that the call can reach.
2279 if (!parameters->options().shared()
2280 || r_type != elfcpp::R_386_PC32)
2281 target->make_plt_entry(symtab, layout, gsym);
2282 }
2283 // Make a dynamic relocation if necessary.
2284 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2285 {
2286 if (parameters->options().output_is_executable()
2287 && gsym->may_need_copy_reloc())
2288 {
2289 target->copy_reloc(symtab, layout, object,
2290 data_shndx, output_section, gsym, reloc);
2291 }
2292 else
2293 {
2294 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2295 rel_dyn->add_global(gsym, r_type, output_section, object,
2296 data_shndx, reloc.get_r_offset());
2297 }
2298 }
2299 }
2300 break;
2301
2302 case elfcpp::R_386_GOT32:
2303 case elfcpp::R_386_GOT32X:
2304 {
2305 // The symbol requires a GOT section.
2306 Output_data_got<32, false>* got = target->got_section(symtab, layout);
2307
2308 // If we convert this from
2309 // mov foo@GOT(%reg), %reg
2310 // to
2311 // lea foo@GOTOFF(%reg), %reg
2312 // in Relocate::relocate, then there is nothing to do here.
2313 if (reloc.get_r_offset() >= 2
2314 && Target_i386::can_convert_mov_to_lea(gsym))
2315 {
2316 section_size_type stype;
2317 const unsigned char* view = object->section_contents(data_shndx,
2318 &stype, true);
2319 if (view[reloc.get_r_offset() - 2] == 0x8b)
2320 break;
2321 }
2322
2323 if (gsym->final_value_is_known())
2324 {
2325 // For a STT_GNU_IFUNC symbol we want the PLT address.
2326 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2327 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2328 else
2329 got->add_global(gsym, GOT_TYPE_STANDARD);
2330 }
2331 else
2332 {
2333 // If this symbol is not fully resolved, we need to add a
2334 // GOT entry with a dynamic relocation.
2335 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2336
2337 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2338 //
2339 // 1) The symbol may be defined in some other module.
2340 //
2341 // 2) We are building a shared library and this is a
2342 // protected symbol; using GLOB_DAT means that the dynamic
2343 // linker can use the address of the PLT in the main
2344 // executable when appropriate so that function address
2345 // comparisons work.
2346 //
2347 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2348 // code, again so that function address comparisons work.
2349 if (gsym->is_from_dynobj()
2350 || gsym->is_undefined()
2351 || gsym->is_preemptible()
2352 || (gsym->visibility() == elfcpp::STV_PROTECTED
2353 && parameters->options().shared())
2354 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2355 && parameters->options().output_is_position_independent()))
2356 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
2357 rel_dyn, elfcpp::R_386_GLOB_DAT);
2358 else
2359 {
2360 // For a STT_GNU_IFUNC symbol we want to write the PLT
2361 // offset into the GOT, so that function pointer
2362 // comparisons work correctly.
2363 bool is_new;
2364 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2365 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2366 else
2367 {
2368 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2369 // Tell the dynamic linker to use the PLT address
2370 // when resolving relocations.
2371 if (gsym->is_from_dynobj()
2372 && !parameters->options().shared())
2373 gsym->set_needs_dynsym_value();
2374 }
2375 if (is_new)
2376 {
2377 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2378 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2379 got, got_off);
2380 }
2381 }
2382 }
2383 }
2384 break;
2385
2386 case elfcpp::R_386_PLT32:
2387 // If the symbol is fully resolved, this is just a PC32 reloc.
2388 // Otherwise we need a PLT entry.
2389 if (gsym->final_value_is_known())
2390 break;
2391 // If building a shared library, we can also skip the PLT entry
2392 // if the symbol is defined in the output file and is protected
2393 // or hidden.
2394 if (gsym->is_defined()
2395 && !gsym->is_from_dynobj()
2396 && !gsym->is_preemptible())
2397 break;
2398 target->make_plt_entry(symtab, layout, gsym);
2399 break;
2400
2401 case elfcpp::R_386_GOTOFF:
2402 // A GOT-relative reference must resolve locally.
2403 if (!gsym->is_defined())
2404 gold_error(_("%s: relocation R_386_GOTOFF against undefined symbol %s"
2405 " cannot be used when making a shared object"),
2406 object->name().c_str(), gsym->name());
2407 else if (gsym->is_from_dynobj())
2408 gold_error(_("%s: relocation R_386_GOTOFF against external symbol %s"
2409 " cannot be used when making a shared object"),
2410 object->name().c_str(), gsym->name());
2411 else if (gsym->is_preemptible())
2412 gold_error(_("%s: relocation R_386_GOTOFF against preemptible symbol %s"
2413 " cannot be used when making a shared object"),
2414 object->name().c_str(), gsym->name());
2415 // We need a GOT section.
2416 target->got_section(symtab, layout);
2417 break;
2418
2419 case elfcpp::R_386_GOTPC:
2420 // We need a GOT section.
2421 target->got_section(symtab, layout);
2422 break;
2423
2424 // These are relocations which should only be seen by the
2425 // dynamic linker, and should never be seen here.
2426 case elfcpp::R_386_COPY:
2427 case elfcpp::R_386_GLOB_DAT:
2428 case elfcpp::R_386_JUMP_SLOT:
2429 case elfcpp::R_386_RELATIVE:
2430 case elfcpp::R_386_IRELATIVE:
2431 case elfcpp::R_386_TLS_TPOFF:
2432 case elfcpp::R_386_TLS_DTPMOD32:
2433 case elfcpp::R_386_TLS_DTPOFF32:
2434 case elfcpp::R_386_TLS_TPOFF32:
2435 case elfcpp::R_386_TLS_DESC:
2436 gold_error(_("%s: unexpected reloc %u in object file"),
2437 object->name().c_str(), r_type);
2438 break;
2439
2440 // These are initial tls relocs, which are expected when
2441 // linking.
2442 case elfcpp::R_386_TLS_GD: // Global-dynamic
2443 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2444 case elfcpp::R_386_TLS_DESC_CALL:
2445 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2446 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2447 case elfcpp::R_386_TLS_IE: // Initial-exec
2448 case elfcpp::R_386_TLS_IE_32:
2449 case elfcpp::R_386_TLS_GOTIE:
2450 case elfcpp::R_386_TLS_LE: // Local-exec
2451 case elfcpp::R_386_TLS_LE_32:
2452 {
2453 const bool is_final = gsym->final_value_is_known();
2454 const tls::Tls_optimization optimized_type
2455 = Target_i386::optimize_tls_reloc(is_final, r_type);
2456 switch (r_type)
2457 {
2458 case elfcpp::R_386_TLS_GD: // Global-dynamic
2459 if (optimized_type == tls::TLSOPT_NONE)
2460 {
2461 // Create a pair of GOT entries for the module index and
2462 // dtv-relative offset.
2463 Output_data_got<32, false>* got
2464 = target->got_section(symtab, layout);
2465 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2466 target->rel_dyn_section(layout),
2467 elfcpp::R_386_TLS_DTPMOD32,
2468 elfcpp::R_386_TLS_DTPOFF32);
2469 }
2470 else if (optimized_type == tls::TLSOPT_TO_IE)
2471 {
2472 // Create a GOT entry for the tp-relative offset.
2473 Output_data_got<32, false>* got
2474 = target->got_section(symtab, layout);
2475 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2476 target->rel_dyn_section(layout),
2477 elfcpp::R_386_TLS_TPOFF);
2478 }
2479 else if (optimized_type != tls::TLSOPT_TO_LE)
2480 unsupported_reloc_global(object, r_type, gsym);
2481 break;
2482
2483 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
2484 target->define_tls_base_symbol(symtab, layout);
2485 if (optimized_type == tls::TLSOPT_NONE)
2486 {
2487 // Create a double GOT entry with an R_386_TLS_DESC
2488 // reloc. The R_386_TLS_DESC reloc is resolved
2489 // lazily, so the GOT entry needs to be in an area in
2490 // .got.plt, not .got. Call got_section to make sure
2491 // the section has been created.
2492 target->got_section(symtab, layout);
2493 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2494 Reloc_section* rt = target->rel_tls_desc_section(layout);
2495 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2496 elfcpp::R_386_TLS_DESC, 0);
2497 }
2498 else if (optimized_type == tls::TLSOPT_TO_IE)
2499 {
2500 // Create a GOT entry for the tp-relative offset.
2501 Output_data_got<32, false>* got
2502 = target->got_section(symtab, layout);
2503 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2504 target->rel_dyn_section(layout),
2505 elfcpp::R_386_TLS_TPOFF);
2506 }
2507 else if (optimized_type != tls::TLSOPT_TO_LE)
2508 unsupported_reloc_global(object, r_type, gsym);
2509 break;
2510
2511 case elfcpp::R_386_TLS_DESC_CALL:
2512 break;
2513
2514 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2515 if (optimized_type == tls::TLSOPT_NONE)
2516 {
2517 // Create a GOT entry for the module index.
2518 target->got_mod_index_entry(symtab, layout, object);
2519 }
2520 else if (optimized_type != tls::TLSOPT_TO_LE)
2521 unsupported_reloc_global(object, r_type, gsym);
2522 break;
2523
2524 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2525 break;
2526
2527 case elfcpp::R_386_TLS_IE: // Initial-exec
2528 case elfcpp::R_386_TLS_IE_32:
2529 case elfcpp::R_386_TLS_GOTIE:
2530 layout->set_has_static_tls();
2531 if (optimized_type == tls::TLSOPT_NONE)
2532 {
2533 // For the R_386_TLS_IE relocation, we need to create a
2534 // dynamic relocation when building a shared library.
2535 if (r_type == elfcpp::R_386_TLS_IE
2536 && parameters->options().shared())
2537 {
2538 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2539 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2540 output_section, object,
2541 data_shndx,
2542 reloc.get_r_offset());
2543 }
2544 // Create a GOT entry for the tp-relative offset.
2545 Output_data_got<32, false>* got
2546 = target->got_section(symtab, layout);
2547 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2548 ? elfcpp::R_386_TLS_TPOFF32
2549 : elfcpp::R_386_TLS_TPOFF);
2550 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2551 ? GOT_TYPE_TLS_OFFSET
2552 : GOT_TYPE_TLS_NOFFSET);
2553 got->add_global_with_rel(gsym, got_type,
2554 target->rel_dyn_section(layout),
2555 dyn_r_type);
2556 }
2557 else if (optimized_type != tls::TLSOPT_TO_LE)
2558 unsupported_reloc_global(object, r_type, gsym);
2559 break;
2560
2561 case elfcpp::R_386_TLS_LE: // Local-exec
2562 case elfcpp::R_386_TLS_LE_32:
2563 layout->set_has_static_tls();
2564 if (parameters->options().shared())
2565 {
2566 // We need to create a dynamic relocation.
2567 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2568 ? elfcpp::R_386_TLS_TPOFF32
2569 : elfcpp::R_386_TLS_TPOFF);
2570 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2571 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
2572 data_shndx, reloc.get_r_offset());
2573 }
2574 break;
2575
2576 default:
2577 gold_unreachable();
2578 }
2579 }
2580 break;
2581
2582 case elfcpp::R_386_32PLT:
2583 case elfcpp::R_386_TLS_GD_32:
2584 case elfcpp::R_386_TLS_GD_PUSH:
2585 case elfcpp::R_386_TLS_GD_CALL:
2586 case elfcpp::R_386_TLS_GD_POP:
2587 case elfcpp::R_386_TLS_LDM_32:
2588 case elfcpp::R_386_TLS_LDM_PUSH:
2589 case elfcpp::R_386_TLS_LDM_CALL:
2590 case elfcpp::R_386_TLS_LDM_POP:
2591 case elfcpp::R_386_USED_BY_INTEL_200:
2592 default:
2593 unsupported_reloc_global(object, r_type, gsym);
2594 break;
2595 }
2596 }
2597
2598 // Process relocations for gc.
2599
2600 void
2601 Target_i386::gc_process_relocs(Symbol_table* symtab,
2602 Layout* layout,
2603 Sized_relobj_file<32, false>* object,
2604 unsigned int data_shndx,
2605 unsigned int,
2606 const unsigned char* prelocs,
2607 size_t reloc_count,
2608 Output_section* output_section,
2609 bool needs_special_offset_handling,
2610 size_t local_symbol_count,
2611 const unsigned char* plocal_symbols)
2612 {
2613 gold::gc_process_relocs<32, false, Target_i386, Scan, Classify_reloc>(
2614 symtab,
2615 layout,
2616 this,
2617 object,
2618 data_shndx,
2619 prelocs,
2620 reloc_count,
2621 output_section,
2622 needs_special_offset_handling,
2623 local_symbol_count,
2624 plocal_symbols);
2625 }
2626
2627 // Scan relocations for a section.
2628
2629 void
2630 Target_i386::scan_relocs(Symbol_table* symtab,
2631 Layout* layout,
2632 Sized_relobj_file<32, false>* object,
2633 unsigned int data_shndx,
2634 unsigned int sh_type,
2635 const unsigned char* prelocs,
2636 size_t reloc_count,
2637 Output_section* output_section,
2638 bool needs_special_offset_handling,
2639 size_t local_symbol_count,
2640 const unsigned char* plocal_symbols)
2641 {
2642 if (sh_type == elfcpp::SHT_RELA)
2643 {
2644 gold_error(_("%s: unsupported RELA reloc section"),
2645 object->name().c_str());
2646 return;
2647 }
2648
2649 gold::scan_relocs<32, false, Target_i386, Scan, Classify_reloc>(
2650 symtab,
2651 layout,
2652 this,
2653 object,
2654 data_shndx,
2655 prelocs,
2656 reloc_count,
2657 output_section,
2658 needs_special_offset_handling,
2659 local_symbol_count,
2660 plocal_symbols);
2661 }
2662
2663 // Finalize the sections.
2664
2665 void
2666 Target_i386::do_finalize_sections(
2667 Layout* layout,
2668 const Input_objects*,
2669 Symbol_table* symtab)
2670 {
2671 const Reloc_section* rel_plt = (this->plt_ == NULL
2672 ? NULL
2673 : this->plt_->rel_plt());
2674 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
2675 this->rel_dyn_, true, false);
2676
2677 // Emit any relocs we saved in an attempt to avoid generating COPY
2678 // relocs.
2679 if (this->copy_relocs_.any_saved_relocs())
2680 this->copy_relocs_.emit(this->rel_dyn_section(layout));
2681
2682 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2683 // the .got.plt section.
2684 Symbol* sym = this->global_offset_table_;
2685 if (sym != NULL)
2686 {
2687 uint32_t data_size = this->got_plt_->current_data_size();
2688 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
2689 }
2690
2691 if (parameters->doing_static_link()
2692 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2693 {
2694 // If linking statically, make sure that the __rel_iplt symbols
2695 // were defined if necessary, even if we didn't create a PLT.
2696 static const Define_symbol_in_segment syms[] =
2697 {
2698 {
2699 "__rel_iplt_start", // name
2700 elfcpp::PT_LOAD, // segment_type
2701 elfcpp::PF_W, // segment_flags_set
2702 elfcpp::PF(0), // segment_flags_clear
2703 0, // value
2704 0, // size
2705 elfcpp::STT_NOTYPE, // type
2706 elfcpp::STB_GLOBAL, // binding
2707 elfcpp::STV_HIDDEN, // visibility
2708 0, // nonvis
2709 Symbol::SEGMENT_START, // offset_from_base
2710 true // only_if_ref
2711 },
2712 {
2713 "__rel_iplt_end", // name
2714 elfcpp::PT_LOAD, // segment_type
2715 elfcpp::PF_W, // segment_flags_set
2716 elfcpp::PF(0), // segment_flags_clear
2717 0, // value
2718 0, // size
2719 elfcpp::STT_NOTYPE, // type
2720 elfcpp::STB_GLOBAL, // binding
2721 elfcpp::STV_HIDDEN, // visibility
2722 0, // nonvis
2723 Symbol::SEGMENT_START, // offset_from_base
2724 true // only_if_ref
2725 }
2726 };
2727
2728 symtab->define_symbols(layout, 2, syms,
2729 layout->script_options()->saw_sections_clause());
2730 }
2731 }
2732
2733 // Return whether a direct absolute static relocation needs to be applied.
2734 // In cases where Scan::local() or Scan::global() has created
2735 // a dynamic relocation other than R_386_RELATIVE, the addend
2736 // of the relocation is carried in the data, and we must not
2737 // apply the static relocation.
2738
2739 inline bool
2740 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
2741 unsigned int r_type,
2742 bool is_32bit,
2743 Output_section* output_section)
2744 {
2745 // If the output section is not allocated, then we didn't call
2746 // scan_relocs, we didn't create a dynamic reloc, and we must apply
2747 // the reloc here.
2748 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
2749 return true;
2750
2751 int ref_flags = Scan::get_reference_flags(r_type);
2752
2753 // For local symbols, we will have created a non-RELATIVE dynamic
2754 // relocation only if (a) the output is position independent,
2755 // (b) the relocation is absolute (not pc- or segment-relative), and
2756 // (c) the relocation is not 32 bits wide.
2757 if (gsym == NULL)
2758 return !(parameters->options().output_is_position_independent()
2759 && (ref_flags & Symbol::ABSOLUTE_REF)
2760 && !is_32bit);
2761
2762 // For global symbols, we use the same helper routines used in the
2763 // scan pass. If we did not create a dynamic relocation, or if we
2764 // created a RELATIVE dynamic relocation, we should apply the static
2765 // relocation.
2766 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
2767 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
2768 && gsym->can_use_relative_reloc(ref_flags
2769 & Symbol::FUNCTION_CALL);
2770 return !has_dyn || is_rel;
2771 }
2772
2773 // Perform a relocation.
2774
2775 inline bool
2776 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
2777 unsigned int,
2778 Target_i386* target,
2779 Output_section* output_section,
2780 size_t relnum,
2781 const unsigned char* preloc,
2782 const Sized_symbol<32>* gsym,
2783 const Symbol_value<32>* psymval,
2784 unsigned char* view,
2785 elfcpp::Elf_types<32>::Elf_Addr address,
2786 section_size_type view_size)
2787 {
2788 const elfcpp::Rel<32, false> rel(preloc);
2789 unsigned int r_type = elfcpp::elf_r_type<32>(rel.get_r_info());
2790
2791 if (this->skip_call_tls_get_addr_)
2792 {
2793 if ((r_type != elfcpp::R_386_PLT32
2794 && r_type != elfcpp::R_386_GOT32X
2795 && r_type != elfcpp::R_386_PC32)
2796 || gsym == NULL
2797 || strcmp(gsym->name(), "___tls_get_addr") != 0)
2798 {
2799 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2800 _("missing expected TLS relocation"));
2801 this->skip_call_tls_get_addr_ = false;
2802 }
2803 else
2804 {
2805 this->skip_call_tls_get_addr_ = false;
2806 return false;
2807 }
2808 }
2809
2810 if (view == NULL)
2811 return true;
2812
2813 const Sized_relobj_file<32, false>* object = relinfo->object;
2814
2815 // Pick the value to use for symbols defined in shared objects.
2816 Symbol_value<32> symval;
2817 if (gsym != NULL
2818 && gsym->type() == elfcpp::STT_GNU_IFUNC
2819 && r_type == elfcpp::R_386_32
2820 && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
2821 && gsym->can_use_relative_reloc(false)
2822 && !gsym->is_from_dynobj()
2823 && !gsym->is_undefined()
2824 && !gsym->is_preemptible())
2825 {
2826 // In this case we are generating a R_386_IRELATIVE reloc. We
2827 // want to use the real value of the symbol, not the PLT offset.
2828 }
2829 else if (gsym != NULL
2830 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2831 {
2832 symval.set_output_value(target->plt_address_for_global(gsym));
2833 psymval = &symval;
2834 }
2835 else if (gsym == NULL && psymval->is_ifunc_symbol())
2836 {
2837 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2838 if (object->local_has_plt_offset(r_sym))
2839 {
2840 symval.set_output_value(target->plt_address_for_local(object, r_sym));
2841 psymval = &symval;
2842 }
2843 }
2844
2845 bool baseless;
2846
2847 switch (r_type)
2848 {
2849 case elfcpp::R_386_NONE:
2850 case elfcpp::R_386_GNU_VTINHERIT:
2851 case elfcpp::R_386_GNU_VTENTRY:
2852 break;
2853
2854 case elfcpp::R_386_32:
2855 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2856 Relocate_functions<32, false>::rel32(view, object, psymval);
2857 break;
2858
2859 case elfcpp::R_386_PC32:
2860 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2861 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2862 break;
2863
2864 case elfcpp::R_386_16:
2865 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2866 Relocate_functions<32, false>::rel16(view, object, psymval);
2867 break;
2868
2869 case elfcpp::R_386_PC16:
2870 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2871 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
2872 break;
2873
2874 case elfcpp::R_386_8:
2875 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2876 Relocate_functions<32, false>::rel8(view, object, psymval);
2877 break;
2878
2879 case elfcpp::R_386_PC8:
2880 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2881 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
2882 break;
2883
2884 case elfcpp::R_386_PLT32:
2885 gold_assert(gsym == NULL
2886 || gsym->has_plt_offset()
2887 || gsym->final_value_is_known()
2888 || (gsym->is_defined()
2889 && !gsym->is_from_dynobj()
2890 && !gsym->is_preemptible()));
2891 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2892 break;
2893
2894 case elfcpp::R_386_GOT32:
2895 case elfcpp::R_386_GOT32X:
2896 baseless = (view[-1] & 0xc7) == 0x5;
2897 // R_386_GOT32 and R_386_GOT32X don't work without base register
2898 // when generating a position-independent output file.
2899 if (baseless
2900 && parameters->options().output_is_position_independent())
2901 {
2902 if(gsym)
2903 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2904 _("unexpected reloc %u against global symbol %s without base register in object file when generating a position-independent output file"),
2905 r_type, gsym->demangled_name().c_str());
2906 else
2907 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2908 _("unexpected reloc %u against local symbol without base register in object file when generating a position-independent output file"),
2909 r_type);
2910 }
2911
2912 // Convert
2913 // mov foo@GOT(%reg), %reg
2914 // to
2915 // lea foo@GOTOFF(%reg), %reg
2916 // if possible.
2917 if (rel.get_r_offset() >= 2
2918 && view[-2] == 0x8b
2919 && ((gsym == NULL && !psymval->is_ifunc_symbol())
2920 || (gsym != NULL
2921 && Target_i386::can_convert_mov_to_lea(gsym))))
2922 {
2923 view[-2] = 0x8d;
2924 elfcpp::Elf_types<32>::Elf_Addr value;
2925 value = psymval->value(object, 0);
2926 // Don't subtract the .got.plt section address for baseless
2927 // addressing.
2928 if (!baseless)
2929 value -= target->got_plt_section()->address();
2930 Relocate_functions<32, false>::rel32(view, value);
2931 }
2932 else
2933 {
2934 // The GOT pointer points to the end of the GOT section.
2935 // We need to subtract the size of the GOT section to get
2936 // the actual offset to use in the relocation.
2937 unsigned int got_offset = 0;
2938 if (gsym != NULL)
2939 {
2940 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2941 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
2942 - target->got_size());
2943 }
2944 else
2945 {
2946 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2947 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2948 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2949 - target->got_size());
2950 }
2951 // Add the .got.plt section address for baseless addressing.
2952 if (baseless)
2953 got_offset += target->got_plt_section()->address();
2954 Relocate_functions<32, false>::rel32(view, got_offset);
2955 }
2956 break;
2957
2958 case elfcpp::R_386_GOTOFF:
2959 {
2960 elfcpp::Elf_types<32>::Elf_Addr reladdr;
2961 reladdr = target->got_plt_section()->address();
2962 Relocate_functions<32, false>::pcrel32(view, object, psymval, reladdr);
2963 }
2964 break;
2965
2966 case elfcpp::R_386_GOTPC:
2967 {
2968 elfcpp::Elf_types<32>::Elf_Addr value;
2969 value = target->got_plt_section()->address();
2970 Relocate_functions<32, false>::pcrel32(view, value, address);
2971 }
2972 break;
2973
2974 case elfcpp::R_386_COPY:
2975 case elfcpp::R_386_GLOB_DAT:
2976 case elfcpp::R_386_JUMP_SLOT:
2977 case elfcpp::R_386_RELATIVE:
2978 case elfcpp::R_386_IRELATIVE:
2979 // These are outstanding tls relocs, which are unexpected when
2980 // linking.
2981 case elfcpp::R_386_TLS_TPOFF:
2982 case elfcpp::R_386_TLS_DTPMOD32:
2983 case elfcpp::R_386_TLS_DTPOFF32:
2984 case elfcpp::R_386_TLS_TPOFF32:
2985 case elfcpp::R_386_TLS_DESC:
2986 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2987 _("unexpected reloc %u in object file"),
2988 r_type);
2989 break;
2990
2991 // These are initial tls relocs, which are expected when
2992 // linking.
2993 case elfcpp::R_386_TLS_GD: // Global-dynamic
2994 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2995 case elfcpp::R_386_TLS_DESC_CALL:
2996 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2997 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2998 case elfcpp::R_386_TLS_IE: // Initial-exec
2999 case elfcpp::R_386_TLS_IE_32:
3000 case elfcpp::R_386_TLS_GOTIE:
3001 case elfcpp::R_386_TLS_LE: // Local-exec
3002 case elfcpp::R_386_TLS_LE_32:
3003 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
3004 view, address, view_size);
3005 break;
3006
3007 case elfcpp::R_386_32PLT:
3008 case elfcpp::R_386_TLS_GD_32:
3009 case elfcpp::R_386_TLS_GD_PUSH:
3010 case elfcpp::R_386_TLS_GD_CALL:
3011 case elfcpp::R_386_TLS_GD_POP:
3012 case elfcpp::R_386_TLS_LDM_32:
3013 case elfcpp::R_386_TLS_LDM_PUSH:
3014 case elfcpp::R_386_TLS_LDM_CALL:
3015 case elfcpp::R_386_TLS_LDM_POP:
3016 case elfcpp::R_386_USED_BY_INTEL_200:
3017 default:
3018 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3019 _("unsupported reloc %u"),
3020 r_type);
3021 break;
3022 }
3023
3024 return true;
3025 }
3026
3027 // Perform a TLS relocation.
3028
3029 inline void
3030 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
3031 Target_i386* target,
3032 size_t relnum,
3033 const elfcpp::Rel<32, false>& rel,
3034 unsigned int r_type,
3035 const Sized_symbol<32>* gsym,
3036 const Symbol_value<32>* psymval,
3037 unsigned char* view,
3038 elfcpp::Elf_types<32>::Elf_Addr,
3039 section_size_type view_size)
3040 {
3041 Output_segment* tls_segment = relinfo->layout->tls_segment();
3042
3043 const Sized_relobj_file<32, false>* object = relinfo->object;
3044
3045 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
3046
3047 const bool is_final = (gsym == NULL
3048 ? !parameters->options().shared()
3049 : gsym->final_value_is_known());
3050 const tls::Tls_optimization optimized_type
3051 = Target_i386::optimize_tls_reloc(is_final, r_type);
3052 switch (r_type)
3053 {
3054 case elfcpp::R_386_TLS_GD: // Global-dynamic
3055 if (optimized_type == tls::TLSOPT_TO_LE)
3056 {
3057 if (tls_segment == NULL)
3058 {
3059 gold_assert(parameters->errors()->error_count() > 0
3060 || issue_undefined_symbol_error(gsym));
3061 return;
3062 }
3063 this->tls_gd_to_le(relinfo, relnum, tls_segment,
3064 rel, r_type, value, view,
3065 view_size);
3066 break;
3067 }
3068 else
3069 {
3070 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3071 ? GOT_TYPE_TLS_NOFFSET
3072 : GOT_TYPE_TLS_PAIR);
3073 unsigned int got_offset;
3074 if (gsym != NULL)
3075 {
3076 gold_assert(gsym->has_got_offset(got_type));
3077 got_offset = gsym->got_offset(got_type) - target->got_size();
3078 }
3079 else
3080 {
3081 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3082 gold_assert(object->local_has_got_offset(r_sym, got_type));
3083 got_offset = (object->local_got_offset(r_sym, got_type)
3084 - target->got_size());
3085 }
3086 if (optimized_type == tls::TLSOPT_TO_IE)
3087 {
3088 this->tls_gd_to_ie(relinfo, relnum, rel, r_type,
3089 got_offset, view, view_size);
3090 break;
3091 }
3092 else if (optimized_type == tls::TLSOPT_NONE)
3093 {
3094 // Relocate the field with the offset of the pair of GOT
3095 // entries.
3096 Relocate_functions<32, false>::rel32(view, got_offset);
3097 break;
3098 }
3099 }
3100 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3101 _("unsupported reloc %u"),
3102 r_type);
3103 break;
3104
3105 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3106 case elfcpp::R_386_TLS_DESC_CALL:
3107 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3108 if (optimized_type == tls::TLSOPT_TO_LE)
3109 {
3110 if (tls_segment == NULL)
3111 {
3112 gold_assert(parameters->errors()->error_count() > 0
3113 || issue_undefined_symbol_error(gsym));
3114 return;
3115 }
3116 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3117 rel, r_type, value, view,
3118 view_size);
3119 break;
3120 }
3121 else
3122 {
3123 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3124 ? GOT_TYPE_TLS_NOFFSET
3125 : GOT_TYPE_TLS_DESC);
3126 unsigned int got_offset = 0;
3127 if (r_type == elfcpp::R_386_TLS_GOTDESC
3128 && optimized_type == tls::TLSOPT_NONE)
3129 {
3130 // We created GOT entries in the .got.tlsdesc portion of
3131 // the .got.plt section, but the offset stored in the
3132 // symbol is the offset within .got.tlsdesc.
3133 got_offset = (target->got_size()
3134 + target->got_plt_section()->data_size());
3135 }
3136 if (gsym != NULL)
3137 {
3138 gold_assert(gsym->has_got_offset(got_type));
3139 got_offset += gsym->got_offset(got_type) - target->got_size();
3140 }
3141 else
3142 {
3143 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3144 gold_assert(object->local_has_got_offset(r_sym, got_type));
3145 got_offset += (object->local_got_offset(r_sym, got_type)
3146 - target->got_size());
3147 }
3148 if (optimized_type == tls::TLSOPT_TO_IE)
3149 {
3150 this->tls_desc_gd_to_ie(relinfo, relnum, rel, r_type,
3151 got_offset, view, view_size);
3152 break;
3153 }
3154 else if (optimized_type == tls::TLSOPT_NONE)
3155 {
3156 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3157 {
3158 // Relocate the field with the offset of the pair of GOT
3159 // entries.
3160 Relocate_functions<32, false>::rel32(view, got_offset);
3161 }
3162 break;
3163 }
3164 }
3165 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3166 _("unsupported reloc %u"),
3167 r_type);
3168 break;
3169
3170 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3171 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
3172 {
3173 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3174 _("both SUN and GNU model "
3175 "TLS relocations"));
3176 break;
3177 }
3178 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3179 if (optimized_type == tls::TLSOPT_TO_LE)
3180 {
3181 if (tls_segment == NULL)
3182 {
3183 gold_assert(parameters->errors()->error_count() > 0
3184 || issue_undefined_symbol_error(gsym));
3185 return;
3186 }
3187 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
3188 value, view, view_size);
3189 break;
3190 }
3191 else if (optimized_type == tls::TLSOPT_NONE)
3192 {
3193 // Relocate the field with the offset of the GOT entry for
3194 // the module index.
3195 unsigned int got_offset;
3196 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3197 - target->got_size());
3198 Relocate_functions<32, false>::rel32(view, got_offset);
3199 break;
3200 }
3201 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3202 _("unsupported reloc %u"),
3203 r_type);
3204 break;
3205
3206 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3207 if (optimized_type == tls::TLSOPT_TO_LE)
3208 {
3209 // This reloc can appear in debugging sections, in which
3210 // case we must not convert to local-exec. We decide what
3211 // to do based on whether the section is marked as
3212 // containing executable code. That is what the GNU linker
3213 // does as well.
3214 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
3215 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
3216 {
3217 if (tls_segment == NULL)
3218 {
3219 gold_assert(parameters->errors()->error_count() > 0
3220 || issue_undefined_symbol_error(gsym));
3221 return;
3222 }
3223 value -= tls_segment->memsz();
3224 }
3225 }
3226 Relocate_functions<32, false>::rel32(view, value);
3227 break;
3228
3229 case elfcpp::R_386_TLS_IE: // Initial-exec
3230 case elfcpp::R_386_TLS_GOTIE:
3231 case elfcpp::R_386_TLS_IE_32:
3232 if (optimized_type == tls::TLSOPT_TO_LE)
3233 {
3234 if (tls_segment == NULL)
3235 {
3236 gold_assert(parameters->errors()->error_count() > 0
3237 || issue_undefined_symbol_error(gsym));
3238 return;
3239 }
3240 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3241 rel, r_type, value, view,
3242 view_size);
3243 break;
3244 }
3245 else if (optimized_type == tls::TLSOPT_NONE)
3246 {
3247 // Relocate the field with the offset of the GOT entry for
3248 // the tp-relative offset of the symbol.
3249 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
3250 ? GOT_TYPE_TLS_OFFSET
3251 : GOT_TYPE_TLS_NOFFSET);
3252 unsigned int got_offset;
3253 if (gsym != NULL)
3254 {
3255 gold_assert(gsym->has_got_offset(got_type));
3256 got_offset = gsym->got_offset(got_type);
3257 }
3258 else
3259 {
3260 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3261 gold_assert(object->local_has_got_offset(r_sym, got_type));
3262 got_offset = object->local_got_offset(r_sym, got_type);
3263 }
3264 // For the R_386_TLS_IE relocation, we need to apply the
3265 // absolute address of the GOT entry.
3266 if (r_type == elfcpp::R_386_TLS_IE)
3267 got_offset += target->got_plt_section()->address();
3268 // All GOT offsets are relative to the end of the GOT.
3269 got_offset -= target->got_size();
3270 Relocate_functions<32, false>::rel32(view, got_offset);
3271 break;
3272 }
3273 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3274 _("unsupported reloc %u"),
3275 r_type);
3276 break;
3277
3278 case elfcpp::R_386_TLS_LE: // Local-exec
3279 // If we're creating a shared library, a dynamic relocation will
3280 // have been created for this location, so do not apply it now.
3281 if (!parameters->options().shared())
3282 {
3283 if (tls_segment == NULL)
3284 {
3285 gold_assert(parameters->errors()->error_count() > 0
3286 || issue_undefined_symbol_error(gsym));
3287 return;
3288 }
3289 value -= tls_segment->memsz();
3290 Relocate_functions<32, false>::rel32(view, value);
3291 }
3292 break;
3293
3294 case elfcpp::R_386_TLS_LE_32:
3295 // If we're creating a shared library, a dynamic relocation will
3296 // have been created for this location, so do not apply it now.
3297 if (!parameters->options().shared())
3298 {
3299 if (tls_segment == NULL)
3300 {
3301 gold_assert(parameters->errors()->error_count() > 0
3302 || issue_undefined_symbol_error(gsym));
3303 return;
3304 }
3305 value = tls_segment->memsz() - value;
3306 Relocate_functions<32, false>::rel32(view, value);
3307 }
3308 break;
3309 }
3310 }
3311
3312 // Do a relocation in which we convert a TLS General-Dynamic to a
3313 // Local-Exec.
3314
3315 inline void
3316 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
3317 size_t relnum,
3318 Output_segment* tls_segment,
3319 const elfcpp::Rel<32, false>& rel,
3320 unsigned int,
3321 elfcpp::Elf_types<32>::Elf_Addr value,
3322 unsigned char* view,
3323 section_size_type view_size)
3324 {
3325 // leal foo(,%ebx,1),%eax; call ___tls_get_addr@PLT
3326 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3327 // leal foo(%ebx),%eax; call ___tls_get_addr@PLT
3328 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3329 // leal foo(%reg),%eax; call *___tls_get_addr@GOT(%reg)
3330 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3331
3332 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3333 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3334
3335 unsigned char op1 = view[-1];
3336 unsigned char op2 = view[-2];
3337 unsigned char op3 = view[4];
3338
3339 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3340 op2 == 0x8d || op2 == 0x04);
3341 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3342 op3 == 0xe8 || op3 == 0xff);
3343
3344 int roff = 5;
3345
3346 if (op2 == 0x04)
3347 {
3348 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3349 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3350 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3351 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3352 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3353 }
3354 else
3355 {
3356 unsigned char reg = op1 & 7;
3357 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3358 ((op1 & 0xf8) == 0x80
3359 && reg != 4
3360 && reg != 0
3361 && (op3 == 0xe8 || (view[5] & 0x7) == reg)));
3362 if (op3 == 0xff
3363 || (rel.get_r_offset() + 9 < view_size
3364 && view[9] == 0x90))
3365 {
3366 // There is an indirect call or a trailing nop. Use the size
3367 // byte subl.
3368 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3369 roff = 6;
3370 }
3371 else
3372 {
3373 // Use the five byte subl.
3374 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3375 }
3376 }
3377
3378 value = tls_segment->memsz() - value;
3379 Relocate_functions<32, false>::rel32(view + roff, value);
3380
3381 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3382 // We can skip it.
3383 this->skip_call_tls_get_addr_ = true;
3384 }
3385
3386 // Do a relocation in which we convert a TLS General-Dynamic to an
3387 // Initial-Exec.
3388
3389 inline void
3390 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
3391 size_t relnum,
3392 const elfcpp::Rel<32, false>& rel,
3393 unsigned int,
3394 elfcpp::Elf_types<32>::Elf_Addr value,
3395 unsigned char* view,
3396 section_size_type view_size)
3397 {
3398 // leal foo(,%ebx,1),%eax; call ___tls_get_addr@PLT
3399 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3400 // leal foo(%ebx),%eax; call ___tls_get_addr@PLT; nop
3401 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3402 // leal foo(%reg),%eax; call *___tls_get_addr@GOT(%reg)
3403 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%reg),%eax
3404
3405 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3406 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3407
3408 unsigned char op1 = view[-1];
3409 unsigned char op2 = view[-2];
3410 unsigned char op3 = view[4];
3411
3412 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3413 op2 == 0x8d || op2 == 0x04);
3414 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3415 op3 == 0xe8 || op3 == 0xff);
3416
3417 int roff;
3418
3419 if (op2 == 0x04)
3420 {
3421 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3422 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3423 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3424 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3425 roff = 5;
3426 }
3427 else
3428 {
3429 unsigned char reg = op1 & 7;
3430 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 10);
3431 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3432 ((op1 & 0xf8) == 0x80
3433 && reg != 4
3434 && reg != 0
3435 && ((op3 == 0xe8 && view[9] == 0x90)
3436 || (view[5] & 0x7) == reg)));
3437 roff = 6;
3438 }
3439
3440 memcpy(view + roff - 8, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
3441 Relocate_functions<32, false>::rel32(view + roff, value);
3442
3443 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3444 // We can skip it.
3445 this->skip_call_tls_get_addr_ = true;
3446 }
3447
3448 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3449 // General-Dynamic to a Local-Exec.
3450
3451 inline void
3452 Target_i386::Relocate::tls_desc_gd_to_le(
3453 const Relocate_info<32, false>* relinfo,
3454 size_t relnum,
3455 Output_segment* tls_segment,
3456 const elfcpp::Rel<32, false>& rel,
3457 unsigned int r_type,
3458 elfcpp::Elf_types<32>::Elf_Addr value,
3459 unsigned char* view,
3460 section_size_type view_size)
3461 {
3462 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3463 {
3464 // leal foo@TLSDESC(%ebx), %eax
3465 // ==> leal foo@NTPOFF, %eax
3466 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3467 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3468 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3469 view[-2] == 0x8d && view[-1] == 0x83);
3470 view[-1] = 0x05;
3471 value -= tls_segment->memsz();
3472 Relocate_functions<32, false>::rel32(view, value);
3473 }
3474 else
3475 {
3476 // call *foo@TLSCALL(%eax)
3477 // ==> nop; nop
3478 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3479 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3480 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3481 view[0] == 0xff && view[1] == 0x10);
3482 view[0] = 0x66;
3483 view[1] = 0x90;
3484 }
3485 }
3486
3487 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3488 // General-Dynamic to an Initial-Exec.
3489
3490 inline void
3491 Target_i386::Relocate::tls_desc_gd_to_ie(
3492 const Relocate_info<32, false>* relinfo,
3493 size_t relnum,
3494 const elfcpp::Rel<32, false>& rel,
3495 unsigned int r_type,
3496 elfcpp::Elf_types<32>::Elf_Addr value,
3497 unsigned char* view,
3498 section_size_type view_size)
3499 {
3500 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3501 {
3502 // leal foo@TLSDESC(%ebx), %eax
3503 // ==> movl foo@GOTNTPOFF(%ebx), %eax
3504 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3505 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3506 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3507 view[-2] == 0x8d && view[-1] == 0x83);
3508 view[-2] = 0x8b;
3509 Relocate_functions<32, false>::rel32(view, value);
3510 }
3511 else
3512 {
3513 // call *foo@TLSCALL(%eax)
3514 // ==> nop; nop
3515 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3516 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3517 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3518 view[0] == 0xff && view[1] == 0x10);
3519 view[0] = 0x66;
3520 view[1] = 0x90;
3521 }
3522 }
3523
3524 // Do a relocation in which we convert a TLS Local-Dynamic to a
3525 // Local-Exec.
3526
3527 inline void
3528 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
3529 size_t relnum,
3530 Output_segment*,
3531 const elfcpp::Rel<32, false>& rel,
3532 unsigned int,
3533 elfcpp::Elf_types<32>::Elf_Addr,
3534 unsigned char* view,
3535 section_size_type view_size)
3536 {
3537 // leal foo(%ebx), %eax; call ___tls_get_addr@PLT
3538 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
3539 // leal foo(%reg), %eax; call call *___tls_get_addr@GOT(%reg)
3540 // ==> movl %gs:0,%eax; leal (%esi),%esi
3541
3542 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3543
3544 unsigned char op1 = view[-1];
3545 unsigned char op2 = view[-2];
3546 unsigned char op3 = view[4];
3547
3548 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3549 op3 == 0xe8 || op3 == 0xff);
3550 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size,
3551 op3 == 0xe8 ? 9 : 10);
3552
3553 // FIXME: Does this test really always pass?
3554 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x8d);
3555
3556 unsigned char reg = op1 & 7;
3557 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3558 ((op1 & 0xf8) == 0x80
3559 && reg != 4
3560 && reg != 0
3561 && (op3 == 0xe8 || (view[5] & 0x7) == reg)));
3562
3563 if (op3 == 0xe8)
3564 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
3565 else
3566 memcpy(view - 2, "\x65\xa1\0\0\0\0\x8d\xb6\0\0\0\0", 12);
3567
3568 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3569 // We can skip it.
3570 this->skip_call_tls_get_addr_ = true;
3571 }
3572
3573 // Do a relocation in which we convert a TLS Initial-Exec to a
3574 // Local-Exec.
3575
3576 inline void
3577 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
3578 size_t relnum,
3579 Output_segment* tls_segment,
3580 const elfcpp::Rel<32, false>& rel,
3581 unsigned int r_type,
3582 elfcpp::Elf_types<32>::Elf_Addr value,
3583 unsigned char* view,
3584 section_size_type view_size)
3585 {
3586 // We have to actually change the instructions, which means that we
3587 // need to examine the opcodes to figure out which instruction we
3588 // are looking at.
3589 if (r_type == elfcpp::R_386_TLS_IE)
3590 {
3591 // movl %gs:XX,%eax ==> movl $YY,%eax
3592 // movl %gs:XX,%reg ==> movl $YY,%reg
3593 // addl %gs:XX,%reg ==> addl $YY,%reg
3594 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
3595 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3596
3597 unsigned char op1 = view[-1];
3598 if (op1 == 0xa1)
3599 {
3600 // movl XX,%eax ==> movl $YY,%eax
3601 view[-1] = 0xb8;
3602 }
3603 else
3604 {
3605 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3606
3607 unsigned char op2 = view[-2];
3608 if (op2 == 0x8b)
3609 {
3610 // movl XX,%reg ==> movl $YY,%reg
3611 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3612 (op1 & 0xc7) == 0x05);
3613 view[-2] = 0xc7;
3614 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3615 }
3616 else if (op2 == 0x03)
3617 {
3618 // addl XX,%reg ==> addl $YY,%reg
3619 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3620 (op1 & 0xc7) == 0x05);
3621 view[-2] = 0x81;
3622 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3623 }
3624 else
3625 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3626 }
3627 }
3628 else
3629 {
3630 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3631 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3632 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3633 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3634 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3635
3636 unsigned char op1 = view[-1];
3637 unsigned char op2 = view[-2];
3638 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3639 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
3640 if (op2 == 0x8b)
3641 {
3642 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3643 view[-2] = 0xc7;
3644 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3645 }
3646 else if (op2 == 0x2b)
3647 {
3648 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3649 view[-2] = 0x81;
3650 view[-1] = 0xe8 | ((op1 >> 3) & 7);
3651 }
3652 else if (op2 == 0x03)
3653 {
3654 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3655 view[-2] = 0x81;
3656 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3657 }
3658 else
3659 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3660 }
3661
3662 value = tls_segment->memsz() - value;
3663 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
3664 value = - value;
3665
3666 Relocate_functions<32, false>::rel32(view, value);
3667 }
3668
3669 // Relocate section data.
3670
3671 void
3672 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
3673 unsigned int sh_type,
3674 const unsigned char* prelocs,
3675 size_t reloc_count,
3676 Output_section* output_section,
3677 bool needs_special_offset_handling,
3678 unsigned char* view,
3679 elfcpp::Elf_types<32>::Elf_Addr address,
3680 section_size_type view_size,
3681 const Reloc_symbol_changes* reloc_symbol_changes)
3682 {
3683 gold_assert(sh_type == elfcpp::SHT_REL);
3684
3685 gold::relocate_section<32, false, Target_i386, Relocate,
3686 gold::Default_comdat_behavior, Classify_reloc>(
3687 relinfo,
3688 this,
3689 prelocs,
3690 reloc_count,
3691 output_section,
3692 needs_special_offset_handling,
3693 view,
3694 address,
3695 view_size,
3696 reloc_symbol_changes);
3697 }
3698
3699 // Return the size of a relocation while scanning during a relocatable
3700 // link.
3701
3702 unsigned int
3703 Target_i386::Classify_reloc::get_size_for_reloc(
3704 unsigned int r_type,
3705 Relobj* object)
3706 {
3707 switch (r_type)
3708 {
3709 case elfcpp::R_386_NONE:
3710 case elfcpp::R_386_GNU_VTINHERIT:
3711 case elfcpp::R_386_GNU_VTENTRY:
3712 case elfcpp::R_386_TLS_GD: // Global-dynamic
3713 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3714 case elfcpp::R_386_TLS_DESC_CALL:
3715 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3716 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3717 case elfcpp::R_386_TLS_IE: // Initial-exec
3718 case elfcpp::R_386_TLS_IE_32:
3719 case elfcpp::R_386_TLS_GOTIE:
3720 case elfcpp::R_386_TLS_LE: // Local-exec
3721 case elfcpp::R_386_TLS_LE_32:
3722 return 0;
3723
3724 case elfcpp::R_386_32:
3725 case elfcpp::R_386_PC32:
3726 case elfcpp::R_386_GOT32:
3727 case elfcpp::R_386_GOT32X:
3728 case elfcpp::R_386_PLT32:
3729 case elfcpp::R_386_GOTOFF:
3730 case elfcpp::R_386_GOTPC:
3731 return 4;
3732
3733 case elfcpp::R_386_16:
3734 case elfcpp::R_386_PC16:
3735 return 2;
3736
3737 case elfcpp::R_386_8:
3738 case elfcpp::R_386_PC8:
3739 return 1;
3740
3741 // These are relocations which should only be seen by the
3742 // dynamic linker, and should never be seen here.
3743 case elfcpp::R_386_COPY:
3744 case elfcpp::R_386_GLOB_DAT:
3745 case elfcpp::R_386_JUMP_SLOT:
3746 case elfcpp::R_386_RELATIVE:
3747 case elfcpp::R_386_IRELATIVE:
3748 case elfcpp::R_386_TLS_TPOFF:
3749 case elfcpp::R_386_TLS_DTPMOD32:
3750 case elfcpp::R_386_TLS_DTPOFF32:
3751 case elfcpp::R_386_TLS_TPOFF32:
3752 case elfcpp::R_386_TLS_DESC:
3753 object->error(_("unexpected reloc %u in object file"), r_type);
3754 return 0;
3755
3756 case elfcpp::R_386_32PLT:
3757 case elfcpp::R_386_TLS_GD_32:
3758 case elfcpp::R_386_TLS_GD_PUSH:
3759 case elfcpp::R_386_TLS_GD_CALL:
3760 case elfcpp::R_386_TLS_GD_POP:
3761 case elfcpp::R_386_TLS_LDM_32:
3762 case elfcpp::R_386_TLS_LDM_PUSH:
3763 case elfcpp::R_386_TLS_LDM_CALL:
3764 case elfcpp::R_386_TLS_LDM_POP:
3765 case elfcpp::R_386_USED_BY_INTEL_200:
3766 default:
3767 object->error(_("unsupported reloc %u in object file"), r_type);
3768 return 0;
3769 }
3770 }
3771
3772 // Scan the relocs during a relocatable link.
3773
3774 void
3775 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
3776 Layout* layout,
3777 Sized_relobj_file<32, false>* object,
3778 unsigned int data_shndx,
3779 unsigned int sh_type,
3780 const unsigned char* prelocs,
3781 size_t reloc_count,
3782 Output_section* output_section,
3783 bool needs_special_offset_handling,
3784 size_t local_symbol_count,
3785 const unsigned char* plocal_symbols,
3786 Relocatable_relocs* rr)
3787 {
3788 typedef gold::Default_scan_relocatable_relocs<Classify_reloc>
3789 Scan_relocatable_relocs;
3790
3791 gold_assert(sh_type == elfcpp::SHT_REL);
3792
3793 gold::scan_relocatable_relocs<32, false, Scan_relocatable_relocs>(
3794 symtab,
3795 layout,
3796 object,
3797 data_shndx,
3798 prelocs,
3799 reloc_count,
3800 output_section,
3801 needs_special_offset_handling,
3802 local_symbol_count,
3803 plocal_symbols,
3804 rr);
3805 }
3806
3807 // Scan the relocs for --emit-relocs.
3808
3809 void
3810 Target_i386::emit_relocs_scan(Symbol_table* symtab,
3811 Layout* layout,
3812 Sized_relobj_file<32, false>* object,
3813 unsigned int data_shndx,
3814 unsigned int sh_type,
3815 const unsigned char* prelocs,
3816 size_t reloc_count,
3817 Output_section* output_section,
3818 bool needs_special_offset_handling,
3819 size_t local_symbol_count,
3820 const unsigned char* plocal_syms,
3821 Relocatable_relocs* rr)
3822 {
3823 typedef gold::Default_classify_reloc<elfcpp::SHT_REL, 32, false>
3824 Classify_reloc;
3825 typedef gold::Default_emit_relocs_strategy<Classify_reloc>
3826 Emit_relocs_strategy;
3827
3828 gold_assert(sh_type == elfcpp::SHT_REL);
3829
3830 gold::scan_relocatable_relocs<32, false, Emit_relocs_strategy>(
3831 symtab,
3832 layout,
3833 object,
3834 data_shndx,
3835 prelocs,
3836 reloc_count,
3837 output_section,
3838 needs_special_offset_handling,
3839 local_symbol_count,
3840 plocal_syms,
3841 rr);
3842 }
3843
3844 // Emit relocations for a section.
3845
3846 void
3847 Target_i386::relocate_relocs(
3848 const Relocate_info<32, false>* relinfo,
3849 unsigned int sh_type,
3850 const unsigned char* prelocs,
3851 size_t reloc_count,
3852 Output_section* output_section,
3853 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
3854 unsigned char* view,
3855 elfcpp::Elf_types<32>::Elf_Addr view_address,
3856 section_size_type view_size,
3857 unsigned char* reloc_view,
3858 section_size_type reloc_view_size)
3859 {
3860 gold_assert(sh_type == elfcpp::SHT_REL);
3861
3862 gold::relocate_relocs<32, false, Classify_reloc>(
3863 relinfo,
3864 prelocs,
3865 reloc_count,
3866 output_section,
3867 offset_in_output_section,
3868 view,
3869 view_address,
3870 view_size,
3871 reloc_view,
3872 reloc_view_size);
3873 }
3874
3875 // Return the value to use for a dynamic which requires special
3876 // treatment. This is how we support equality comparisons of function
3877 // pointers across shared library boundaries, as described in the
3878 // processor specific ABI supplement.
3879
3880 uint64_t
3881 Target_i386::do_dynsym_value(const Symbol* gsym) const
3882 {
3883 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3884 return this->plt_address_for_global(gsym);
3885 }
3886
3887 // Return a string used to fill a code section with nops to take up
3888 // the specified length.
3889
3890 std::string
3891 Target_i386::do_code_fill(section_size_type length) const
3892 {
3893 if (length >= 16)
3894 {
3895 // Build a jmp instruction to skip over the bytes.
3896 unsigned char jmp[5];
3897 jmp[0] = 0xe9;
3898 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3899 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3900 + std::string(length - 5, static_cast<char>(0x90)));
3901 }
3902
3903 // Nop sequences of various lengths.
3904 const char nop1[1] = { '\x90' }; // nop
3905 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
3906 const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi
3907 const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3908 '\x00'};
3909 const char nop5[5] = { '\x90', '\x8d', '\x74', // nop
3910 '\x26', '\x00' }; // leal 0(%esi,1),%esi
3911 const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3912 '\x00', '\x00', '\x00' };
3913 const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3914 '\x00', '\x00', '\x00',
3915 '\x00' };
3916 const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop
3917 '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi
3918 '\x00', '\x00' };
3919 const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi
3920 '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi
3921 '\x00', '\x00', '\x00' };
3922 const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi
3923 '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi
3924 '\x00', '\x00', '\x00',
3925 '\x00' };
3926 const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3927 '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi
3928 '\x27', '\x00', '\x00',
3929 '\x00', '\x00' };
3930 const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3931 '\x00', '\x00', '\x00', // leal 0L(%edi),%edi
3932 '\x8d', '\xbf', '\x00',
3933 '\x00', '\x00', '\x00' };
3934 const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3935 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3936 '\x8d', '\xbc', '\x27',
3937 '\x00', '\x00', '\x00',
3938 '\x00' };
3939 const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3940 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3941 '\x00', '\x8d', '\xbc',
3942 '\x27', '\x00', '\x00',
3943 '\x00', '\x00' };
3944 const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15
3945 '\x90', '\x90', '\x90', // nop,nop,nop,...
3946 '\x90', '\x90', '\x90',
3947 '\x90', '\x90', '\x90',
3948 '\x90', '\x90', '\x90' };
3949
3950 const char* nops[16] = {
3951 NULL,
3952 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3953 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3954 };
3955
3956 return std::string(nops[length], length);
3957 }
3958
3959 // Return the value to use for the base of a DW_EH_PE_datarel offset
3960 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3961 // assembler can not write out the difference between two labels in
3962 // different sections, so instead of using a pc-relative value they
3963 // use an offset from the GOT.
3964
3965 uint64_t
3966 Target_i386::do_ehframe_datarel_base() const
3967 {
3968 gold_assert(this->global_offset_table_ != NULL);
3969 Symbol* sym = this->global_offset_table_;
3970 Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym);
3971 return ssym->value();
3972 }
3973
3974 // Return whether SYM should be treated as a call to a non-split
3975 // function. We don't want that to be true of a call to a
3976 // get_pc_thunk function.
3977
3978 bool
3979 Target_i386::do_is_call_to_non_split(const Symbol* sym,
3980 const unsigned char*,
3981 const unsigned char*,
3982 section_size_type) const
3983 {
3984 return (sym->type() == elfcpp::STT_FUNC
3985 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
3986 }
3987
3988 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3989 // compiled with -fsplit-stack. The function calls non-split-stack
3990 // code. We have to change the function so that it always ensures
3991 // that it has enough stack space to run some random function.
3992
3993 void
3994 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
3995 section_offset_type fnoffset,
3996 section_size_type fnsize,
3997 const unsigned char*,
3998 size_t,
3999 unsigned char* view,
4000 section_size_type view_size,
4001 std::string* from,
4002 std::string* to) const
4003 {
4004 // The function starts with a comparison of the stack pointer and a
4005 // field in the TCB. This is followed by a jump.
4006
4007 // cmp %gs:NN,%esp
4008 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
4009 && fnsize > 7)
4010 {
4011 // We will call __morestack if the carry flag is set after this
4012 // comparison. We turn the comparison into an stc instruction
4013 // and some nops.
4014 view[fnoffset] = '\xf9';
4015 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
4016 }
4017 // lea NN(%esp),%ecx
4018 // lea NN(%esp),%edx
4019 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
4020 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
4021 && fnsize > 7)
4022 {
4023 // This is loading an offset from the stack pointer for a
4024 // comparison. The offset is negative, so we decrease the
4025 // offset by the amount of space we need for the stack. This
4026 // means we will avoid calling __morestack if there happens to
4027 // be plenty of space on the stack already.
4028 unsigned char* pval = view + fnoffset + 3;
4029 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
4030 val -= parameters->options().split_stack_adjust_size();
4031 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
4032 }
4033 else
4034 {
4035 if (!object->has_no_split_stack())
4036 object->error(_("failed to match split-stack sequence at "
4037 "section %u offset %0zx"),
4038 shndx, static_cast<size_t>(fnoffset));
4039 return;
4040 }
4041
4042 // We have to change the function so that it calls
4043 // __morestack_non_split instead of __morestack. The former will
4044 // allocate additional stack space.
4045 *from = "__morestack";
4046 *to = "__morestack_non_split";
4047 }
4048
4049 // The selector for i386 object files. Note this is never instantiated
4050 // directly. It's only used in Target_selector_i386_nacl, below.
4051
4052 class Target_selector_i386 : public Target_selector_freebsd
4053 {
4054 public:
4055 Target_selector_i386()
4056 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
4057 "elf32-i386", "elf32-i386-freebsd",
4058 "elf_i386")
4059 { }
4060
4061 Target*
4062 do_instantiate_target()
4063 { return new Target_i386(); }
4064 };
4065
4066 // NaCl variant. It uses different PLT contents.
4067
4068 class Output_data_plt_i386_nacl : public Output_data_plt_i386
4069 {
4070 public:
4071 Output_data_plt_i386_nacl(Layout* layout,
4072 Output_data_got_plt_i386* got_plt,
4073 Output_data_space* got_irelative)
4074 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
4075 { }
4076
4077 protected:
4078 virtual unsigned int
4079 do_get_plt_entry_size() const
4080 { return plt_entry_size; }
4081
4082 virtual void
4083 do_add_eh_frame(Layout* layout)
4084 {
4085 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
4086 plt_eh_frame_fde, plt_eh_frame_fde_size);
4087 }
4088
4089 // The size of an entry in the PLT.
4090 static const int plt_entry_size = 64;
4091
4092 // The .eh_frame unwind information for the PLT.
4093 static const int plt_eh_frame_fde_size = 32;
4094 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
4095 };
4096
4097 class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl
4098 {
4099 public:
4100 Output_data_plt_i386_nacl_exec(Layout* layout,
4101 Output_data_got_plt_i386* got_plt,
4102 Output_data_space* got_irelative)
4103 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
4104 { }
4105
4106 protected:
4107 virtual void
4108 do_fill_first_plt_entry(unsigned char* pov,
4109 elfcpp::Elf_types<32>::Elf_Addr got_address);
4110
4111 virtual unsigned int
4112 do_fill_plt_entry(unsigned char* pov,
4113 elfcpp::Elf_types<32>::Elf_Addr got_address,
4114 unsigned int got_offset,
4115 unsigned int plt_offset,
4116 unsigned int plt_rel_offset);
4117
4118 private:
4119 // The first entry in the PLT for an executable.
4120 static const unsigned char first_plt_entry[plt_entry_size];
4121
4122 // Other entries in the PLT for an executable.
4123 static const unsigned char plt_entry[plt_entry_size];
4124 };
4125
4126 class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl
4127 {
4128 public:
4129 Output_data_plt_i386_nacl_dyn(Layout* layout,
4130 Output_data_got_plt_i386* got_plt,
4131 Output_data_space* got_irelative)
4132 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
4133 { }
4134
4135 protected:
4136 virtual void
4137 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
4138
4139 virtual unsigned int
4140 do_fill_plt_entry(unsigned char* pov,
4141 elfcpp::Elf_types<32>::Elf_Addr,
4142 unsigned int got_offset,
4143 unsigned int plt_offset,
4144 unsigned int plt_rel_offset);
4145
4146 private:
4147 // The first entry in the PLT for a shared object.
4148 static const unsigned char first_plt_entry[plt_entry_size];
4149
4150 // Other entries in the PLT for a shared object.
4151 static const unsigned char plt_entry[plt_entry_size];
4152 };
4153
4154 class Target_i386_nacl : public Target_i386
4155 {
4156 public:
4157 Target_i386_nacl()
4158 : Target_i386(&i386_nacl_info)
4159 { }
4160
4161 protected:
4162 virtual Output_data_plt_i386*
4163 do_make_data_plt(Layout* layout,
4164 Output_data_got_plt_i386* got_plt,
4165 Output_data_space* got_irelative,
4166 bool dyn)
4167 {
4168 if (dyn)
4169 return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative);
4170 else
4171 return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative);
4172 }
4173
4174 virtual std::string
4175 do_code_fill(section_size_type length) const;
4176
4177 private:
4178 static const Target::Target_info i386_nacl_info;
4179 };
4180
4181 const Target::Target_info Target_i386_nacl::i386_nacl_info =
4182 {
4183 32, // size
4184 false, // is_big_endian
4185 elfcpp::EM_386, // machine_code
4186 false, // has_make_symbol
4187 false, // has_resolve
4188 true, // has_code_fill
4189 true, // is_default_stack_executable
4190 true, // can_icf_inline_merge_sections
4191 '\0', // wrap_char
4192 "/lib/ld-nacl-x86-32.so.1", // dynamic_linker
4193 0x20000, // default_text_segment_address
4194 0x10000, // abi_pagesize (overridable by -z max-page-size)
4195 0x10000, // common_pagesize (overridable by -z common-page-size)
4196 true, // isolate_execinstr
4197 0x10000000, // rosegment_gap
4198 elfcpp::SHN_UNDEF, // small_common_shndx
4199 elfcpp::SHN_UNDEF, // large_common_shndx
4200 0, // small_common_section_flags
4201 0, // large_common_section_flags
4202 NULL, // attributes_section
4203 NULL, // attributes_vendor
4204 "_start", // entry_symbol_name
4205 32, // hash_entry_size
4206 elfcpp::SHT_PROGBITS, // unwind_section_type
4207 };
4208
4209 #define NACLMASK 0xe0 // 32-byte alignment mask
4210
4211 const unsigned char
4212 Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] =
4213 {
4214 0xff, 0x35, // pushl contents of memory address
4215 0, 0, 0, 0, // replaced with address of .got + 4
4216 0x8b, 0x0d, // movl contents of address, %ecx
4217 0, 0, 0, 0, // replaced with address of .got + 8
4218 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4219 0xff, 0xe1, // jmp *%ecx
4220 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4221 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4222 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4223 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4224 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4225 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4226 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4227 0x90, 0x90, 0x90, 0x90, 0x90
4228 };
4229
4230 void
4231 Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry(
4232 unsigned char* pov,
4233 elfcpp::Elf_types<32>::Elf_Addr got_address)
4234 {
4235 memcpy(pov, first_plt_entry, plt_entry_size);
4236 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
4237 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
4238 }
4239
4240 // The first entry in the PLT for a shared object.
4241
4242 const unsigned char
4243 Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] =
4244 {
4245 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
4246 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx
4247 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4248 0xff, 0xe1, // jmp *%ecx
4249 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4250 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4251 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4252 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4253 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4254 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4255 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4256 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4257 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4258 0x90, 0x90, 0x90, 0x90, 0x90 // nops
4259 };
4260
4261 void
4262 Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry(
4263 unsigned char* pov,
4264 elfcpp::Elf_types<32>::Elf_Addr)
4265 {
4266 memcpy(pov, first_plt_entry, plt_entry_size);
4267 }
4268
4269 // Subsequent entries in the PLT for an executable.
4270
4271 const unsigned char
4272 Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] =
4273 {
4274 0x8b, 0x0d, // movl contents of address, %ecx */
4275 0, 0, 0, 0, // replaced with address of symbol in .got
4276 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4277 0xff, 0xe1, // jmp *%ecx
4278
4279 // Pad to the next 32-byte boundary with nop instructions.
4280 0x90,
4281 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4282 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4283
4284 // Lazy GOT entries point here (32-byte aligned).
4285 0x68, // pushl immediate
4286 0, 0, 0, 0, // replaced with offset into relocation table
4287 0xe9, // jmp relative
4288 0, 0, 0, 0, // replaced with offset to start of .plt
4289
4290 // Pad to the next 32-byte boundary with nop instructions.
4291 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4292 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4293 0x90, 0x90
4294 };
4295
4296 unsigned int
4297 Output_data_plt_i386_nacl_exec::do_fill_plt_entry(
4298 unsigned char* pov,
4299 elfcpp::Elf_types<32>::Elf_Addr got_address,
4300 unsigned int got_offset,
4301 unsigned int plt_offset,
4302 unsigned int plt_rel_offset)
4303 {
4304 memcpy(pov, plt_entry, plt_entry_size);
4305 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4306 got_address + got_offset);
4307 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4308 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4309 return 32;
4310 }
4311
4312 // Subsequent entries in the PLT for a shared object.
4313
4314 const unsigned char
4315 Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] =
4316 {
4317 0x8b, 0x8b, // movl offset(%ebx), %ecx
4318 0, 0, 0, 0, // replaced with offset of symbol in .got
4319 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx
4320 0xff, 0xe1, // jmp *%ecx
4321
4322 // Pad to the next 32-byte boundary with nop instructions.
4323 0x90,
4324 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4325 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4326
4327 // Lazy GOT entries point here (32-byte aligned).
4328 0x68, // pushl immediate
4329 0, 0, 0, 0, // replaced with offset into relocation table.
4330 0xe9, // jmp relative
4331 0, 0, 0, 0, // replaced with offset to start of .plt.
4332
4333 // Pad to the next 32-byte boundary with nop instructions.
4334 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4335 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4336 0x90, 0x90
4337 };
4338
4339 unsigned int
4340 Output_data_plt_i386_nacl_dyn::do_fill_plt_entry(
4341 unsigned char* pov,
4342 elfcpp::Elf_types<32>::Elf_Addr,
4343 unsigned int got_offset,
4344 unsigned int plt_offset,
4345 unsigned int plt_rel_offset)
4346 {
4347 memcpy(pov, plt_entry, plt_entry_size);
4348 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
4349 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4350 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4351 return 32;
4352 }
4353
4354 const unsigned char
4355 Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] =
4356 {
4357 0, 0, 0, 0, // Replaced with offset to .plt.
4358 0, 0, 0, 0, // Replaced with size of .plt.
4359 0, // Augmentation size.
4360 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
4361 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
4362 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
4363 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
4364 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
4365 13, // Block length.
4366 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
4367 elfcpp::DW_OP_breg8, 0, // Push %eip.
4368 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
4369 elfcpp::DW_OP_and, // & (%eip & 0x3f).
4370 elfcpp::DW_OP_const1u, 37, // Push 0x25.
4371 elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25)
4372 elfcpp::DW_OP_lit2, // Push 2.
4373 elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2)
4374 elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4
4375 elfcpp::DW_CFA_nop, // Align to 32 bytes.
4376 elfcpp::DW_CFA_nop
4377 };
4378
4379 // Return a string used to fill a code section with nops.
4380 // For NaCl, long NOPs are only valid if they do not cross
4381 // bundle alignment boundaries, so keep it simple with one-byte NOPs.
4382 std::string
4383 Target_i386_nacl::do_code_fill(section_size_type length) const
4384 {
4385 return std::string(length, static_cast<char>(0x90));
4386 }
4387
4388 // The selector for i386-nacl object files.
4389
4390 class Target_selector_i386_nacl
4391 : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl>
4392 {
4393 public:
4394 Target_selector_i386_nacl()
4395 : Target_selector_nacl<Target_selector_i386,
4396 Target_i386_nacl>("x86-32",
4397 "elf32-i386-nacl",
4398 "elf_i386_nacl")
4399 { }
4400 };
4401
4402 Target_selector_i386_nacl target_selector_i386;
4403
4404 // IAMCU variant. It uses EM_IAMCU, not EM_386.
4405
4406 class Target_iamcu : public Target_i386
4407 {
4408 public:
4409 Target_iamcu()
4410 : Target_i386(&iamcu_info)
4411 { }
4412
4413 private:
4414 // Information about this specific target which we pass to the
4415 // general Target structure.
4416 static const Target::Target_info iamcu_info;
4417 };
4418
4419 const Target::Target_info Target_iamcu::iamcu_info =
4420 {
4421 32, // size
4422 false, // is_big_endian
4423 elfcpp::EM_IAMCU, // machine_code
4424 false, // has_make_symbol
4425 false, // has_resolve
4426 true, // has_code_fill
4427 true, // is_default_stack_executable
4428 true, // can_icf_inline_merge_sections
4429 '\0', // wrap_char
4430 "/usr/lib/libc.so.1", // dynamic_linker
4431 0x08048000, // default_text_segment_address
4432 0x1000, // abi_pagesize (overridable by -z max-page-size)
4433 0x1000, // common_pagesize (overridable by -z common-page-size)
4434 false, // isolate_execinstr
4435 0, // rosegment_gap
4436 elfcpp::SHN_UNDEF, // small_common_shndx
4437 elfcpp::SHN_UNDEF, // large_common_shndx
4438 0, // small_common_section_flags
4439 0, // large_common_section_flags
4440 NULL, // attributes_section
4441 NULL, // attributes_vendor
4442 "_start", // entry_symbol_name
4443 32, // hash_entry_size
4444 elfcpp::SHT_PROGBITS, // unwind_section_type
4445 };
4446
4447 class Target_selector_iamcu : public Target_selector
4448 {
4449 public:
4450 Target_selector_iamcu()
4451 : Target_selector(elfcpp::EM_IAMCU, 32, false, "elf32-iamcu",
4452 "elf_iamcu")
4453 { }
4454
4455 Target*
4456 do_instantiate_target()
4457 { return new Target_iamcu(); }
4458 };
4459
4460 Target_selector_iamcu target_selector_iamcu;
4461
4462 } // End anonymous namespace.
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