* output.h (Output_section_lookup_maps::add_merge_section):
[deliverable/binutils-gdb.git] / gold / i386.cc
1 // i386.cc -- i386 target support for gold.
2
3 // Copyright 2006, 2007, 2008, 2009 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 "parameters.h"
29 #include "reloc.h"
30 #include "i386.h"
31 #include "object.h"
32 #include "symtab.h"
33 #include "layout.h"
34 #include "output.h"
35 #include "copy-relocs.h"
36 #include "target.h"
37 #include "target-reloc.h"
38 #include "target-select.h"
39 #include "tls.h"
40 #include "freebsd.h"
41 #include "gc.h"
42
43 namespace
44 {
45
46 using namespace gold;
47
48 class Output_data_plt_i386;
49
50 // The i386 target class.
51 // TLS info comes from
52 // http://people.redhat.com/drepper/tls.pdf
53 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
54
55 class Target_i386 : public Target_freebsd<32, false>
56 {
57 public:
58 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
59
60 Target_i386()
61 : Target_freebsd<32, false>(&i386_info),
62 got_(NULL), plt_(NULL), got_plt_(NULL), global_offset_table_(NULL),
63 rel_dyn_(NULL), copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
64 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
65 { }
66
67 inline bool
68 can_check_for_function_pointers() const
69 { return true; }
70
71 // Process the relocations to determine unreferenced sections for
72 // garbage collection.
73 void
74 gc_process_relocs(Symbol_table* symtab,
75 Layout* layout,
76 Sized_relobj<32, false>* object,
77 unsigned int data_shndx,
78 unsigned int sh_type,
79 const unsigned char* prelocs,
80 size_t reloc_count,
81 Output_section* output_section,
82 bool needs_special_offset_handling,
83 size_t local_symbol_count,
84 const unsigned char* plocal_symbols);
85
86 // Scan the relocations to look for symbol adjustments.
87 void
88 scan_relocs(Symbol_table* symtab,
89 Layout* layout,
90 Sized_relobj<32, false>* object,
91 unsigned int data_shndx,
92 unsigned int sh_type,
93 const unsigned char* prelocs,
94 size_t reloc_count,
95 Output_section* output_section,
96 bool needs_special_offset_handling,
97 size_t local_symbol_count,
98 const unsigned char* plocal_symbols);
99
100 // Finalize the sections.
101 void
102 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
103
104 // Return the value to use for a dynamic which requires special
105 // treatment.
106 uint64_t
107 do_dynsym_value(const Symbol*) const;
108
109 // Relocate a section.
110 void
111 relocate_section(const Relocate_info<32, false>*,
112 unsigned int sh_type,
113 const unsigned char* prelocs,
114 size_t reloc_count,
115 Output_section* output_section,
116 bool needs_special_offset_handling,
117 unsigned char* view,
118 elfcpp::Elf_types<32>::Elf_Addr view_address,
119 section_size_type view_size,
120 const Reloc_symbol_changes*);
121
122 // Scan the relocs during a relocatable link.
123 void
124 scan_relocatable_relocs(Symbol_table* symtab,
125 Layout* layout,
126 Sized_relobj<32, false>* object,
127 unsigned int data_shndx,
128 unsigned int sh_type,
129 const unsigned char* prelocs,
130 size_t reloc_count,
131 Output_section* output_section,
132 bool needs_special_offset_handling,
133 size_t local_symbol_count,
134 const unsigned char* plocal_symbols,
135 Relocatable_relocs*);
136
137 // Relocate a section during a relocatable link.
138 void
139 relocate_for_relocatable(const Relocate_info<32, false>*,
140 unsigned int sh_type,
141 const unsigned char* prelocs,
142 size_t reloc_count,
143 Output_section* output_section,
144 off_t offset_in_output_section,
145 const Relocatable_relocs*,
146 unsigned char* view,
147 elfcpp::Elf_types<32>::Elf_Addr view_address,
148 section_size_type view_size,
149 unsigned char* reloc_view,
150 section_size_type reloc_view_size);
151
152 // Return a string used to fill a code section with nops.
153 std::string
154 do_code_fill(section_size_type length) const;
155
156 // Return whether SYM is defined by the ABI.
157 bool
158 do_is_defined_by_abi(const Symbol* sym) const
159 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
160
161 // Return whether a symbol name implies a local label. The UnixWare
162 // 2.1 cc generates temporary symbols that start with .X, so we
163 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
164 // If so, we should move the .X recognition into
165 // Target::do_is_local_label_name.
166 bool
167 do_is_local_label_name(const char* name) const
168 {
169 if (name[0] == '.' && name[1] == 'X')
170 return true;
171 return Target::do_is_local_label_name(name);
172 }
173
174 // Return whether SYM is call to a non-split function.
175 bool
176 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
177
178 // Adjust -fstack-split code which calls non-stack-split code.
179 void
180 do_calls_non_split(Relobj* object, unsigned int shndx,
181 section_offset_type fnoffset, section_size_type fnsize,
182 unsigned char* view, section_size_type view_size,
183 std::string* from, std::string* to) const;
184
185 // Return the size of the GOT section.
186 section_size_type
187 got_size()
188 {
189 gold_assert(this->got_ != NULL);
190 return this->got_->data_size();
191 }
192
193 private:
194 // The class which scans relocations.
195 struct Scan
196 {
197 inline void
198 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
199 Sized_relobj<32, false>* object,
200 unsigned int data_shndx,
201 Output_section* output_section,
202 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
203 const elfcpp::Sym<32, false>& lsym);
204
205 inline void
206 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
207 Sized_relobj<32, false>* object,
208 unsigned int data_shndx,
209 Output_section* output_section,
210 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
211 Symbol* gsym);
212
213 inline bool
214 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
215 Target_i386* target,
216 Sized_relobj<32, false>* object,
217 unsigned int data_shndx,
218 Output_section* output_section,
219 const elfcpp::Rel<32, false>& reloc,
220 unsigned int r_type,
221 const elfcpp::Sym<32, false>& lsym);
222
223 inline bool
224 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
225 Target_i386* target,
226 Sized_relobj<32, false>* object,
227 unsigned int data_shndx,
228 Output_section* output_section,
229 const elfcpp::Rel<32, false>& reloc,
230 unsigned int r_type,
231 Symbol* gsym);
232
233 inline bool
234 possible_function_pointer_reloc(unsigned int r_type);
235
236 static void
237 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
238
239 static void
240 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
241 Symbol*);
242 };
243
244 // The class which implements relocation.
245 class Relocate
246 {
247 public:
248 Relocate()
249 : skip_call_tls_get_addr_(false),
250 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
251 { }
252
253 ~Relocate()
254 {
255 if (this->skip_call_tls_get_addr_)
256 {
257 // FIXME: This needs to specify the location somehow.
258 gold_error(_("missing expected TLS relocation"));
259 }
260 }
261
262 // Return whether the static relocation needs to be applied.
263 inline bool
264 should_apply_static_reloc(const Sized_symbol<32>* gsym,
265 int ref_flags,
266 bool is_32bit,
267 Output_section* output_section);
268
269 // Do a relocation. Return false if the caller should not issue
270 // any warnings about this relocation.
271 inline bool
272 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
273 size_t relnum, const elfcpp::Rel<32, false>&,
274 unsigned int r_type, const Sized_symbol<32>*,
275 const Symbol_value<32>*,
276 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
277 section_size_type);
278
279 private:
280 // Do a TLS relocation.
281 inline void
282 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
283 size_t relnum, const elfcpp::Rel<32, false>&,
284 unsigned int r_type, const Sized_symbol<32>*,
285 const Symbol_value<32>*,
286 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
287 section_size_type);
288
289 // Do a TLS General-Dynamic to Initial-Exec transition.
290 inline void
291 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
292 Output_segment* tls_segment,
293 const elfcpp::Rel<32, false>&, unsigned int r_type,
294 elfcpp::Elf_types<32>::Elf_Addr value,
295 unsigned char* view,
296 section_size_type view_size);
297
298 // Do a TLS General-Dynamic to Local-Exec transition.
299 inline void
300 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
301 Output_segment* tls_segment,
302 const elfcpp::Rel<32, false>&, unsigned int r_type,
303 elfcpp::Elf_types<32>::Elf_Addr value,
304 unsigned char* view,
305 section_size_type view_size);
306
307 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
308 // transition.
309 inline void
310 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
311 Output_segment* tls_segment,
312 const elfcpp::Rel<32, false>&, unsigned int r_type,
313 elfcpp::Elf_types<32>::Elf_Addr value,
314 unsigned char* view,
315 section_size_type view_size);
316
317 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
318 // transition.
319 inline void
320 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
321 Output_segment* tls_segment,
322 const elfcpp::Rel<32, false>&, unsigned int r_type,
323 elfcpp::Elf_types<32>::Elf_Addr value,
324 unsigned char* view,
325 section_size_type view_size);
326
327 // Do a TLS Local-Dynamic to Local-Exec transition.
328 inline void
329 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
330 Output_segment* tls_segment,
331 const elfcpp::Rel<32, false>&, unsigned int r_type,
332 elfcpp::Elf_types<32>::Elf_Addr value,
333 unsigned char* view,
334 section_size_type view_size);
335
336 // Do a TLS Initial-Exec to Local-Exec transition.
337 static inline void
338 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
339 Output_segment* tls_segment,
340 const elfcpp::Rel<32, false>&, unsigned int r_type,
341 elfcpp::Elf_types<32>::Elf_Addr value,
342 unsigned char* view,
343 section_size_type view_size);
344
345 // We need to keep track of which type of local dynamic relocation
346 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
347 enum Local_dynamic_type
348 {
349 LOCAL_DYNAMIC_NONE,
350 LOCAL_DYNAMIC_SUN,
351 LOCAL_DYNAMIC_GNU
352 };
353
354 // This is set if we should skip the next reloc, which should be a
355 // PLT32 reloc against ___tls_get_addr.
356 bool skip_call_tls_get_addr_;
357 // The type of local dynamic relocation we have seen in the section
358 // being relocated, if any.
359 Local_dynamic_type local_dynamic_type_;
360 };
361
362 // A class which returns the size required for a relocation type,
363 // used while scanning relocs during a relocatable link.
364 class Relocatable_size_for_reloc
365 {
366 public:
367 unsigned int
368 get_size_for_reloc(unsigned int, Relobj*);
369 };
370
371 // Adjust TLS relocation type based on the options and whether this
372 // is a local symbol.
373 static tls::Tls_optimization
374 optimize_tls_reloc(bool is_final, int r_type);
375
376 // Get the GOT section, creating it if necessary.
377 Output_data_got<32, false>*
378 got_section(Symbol_table*, Layout*);
379
380 // Get the GOT PLT section.
381 Output_data_space*
382 got_plt_section() const
383 {
384 gold_assert(this->got_plt_ != NULL);
385 return this->got_plt_;
386 }
387
388 // Create a PLT entry for a global symbol.
389 void
390 make_plt_entry(Symbol_table*, Layout*, Symbol*);
391
392 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
393 void
394 define_tls_base_symbol(Symbol_table*, Layout*);
395
396 // Create a GOT entry for the TLS module index.
397 unsigned int
398 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
399 Sized_relobj<32, false>* object);
400
401 // Get the PLT section.
402 Output_data_plt_i386*
403 plt_section() const
404 {
405 gold_assert(this->plt_ != NULL);
406 return this->plt_;
407 }
408
409 // Get the dynamic reloc section, creating it if necessary.
410 Reloc_section*
411 rel_dyn_section(Layout*);
412
413 // Get the section to use for TLS_DESC relocations.
414 Reloc_section*
415 rel_tls_desc_section(Layout*) const;
416
417 // Add a potential copy relocation.
418 void
419 copy_reloc(Symbol_table* symtab, Layout* layout,
420 Sized_relobj<32, false>* object,
421 unsigned int shndx, Output_section* output_section,
422 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
423 {
424 this->copy_relocs_.copy_reloc(symtab, layout,
425 symtab->get_sized_symbol<32>(sym),
426 object, shndx, output_section, reloc,
427 this->rel_dyn_section(layout));
428 }
429
430 // Information about this specific target which we pass to the
431 // general Target structure.
432 static const Target::Target_info i386_info;
433
434 // The types of GOT entries needed for this platform.
435 enum Got_type
436 {
437 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
438 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
439 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
440 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
441 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
442 };
443
444 // The GOT section.
445 Output_data_got<32, false>* got_;
446 // The PLT section.
447 Output_data_plt_i386* plt_;
448 // The GOT PLT section.
449 Output_data_space* got_plt_;
450 // The _GLOBAL_OFFSET_TABLE_ symbol.
451 Symbol* global_offset_table_;
452 // The dynamic reloc section.
453 Reloc_section* rel_dyn_;
454 // Relocs saved to avoid a COPY reloc.
455 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
456 // Space for variables copied with a COPY reloc.
457 Output_data_space* dynbss_;
458 // Offset of the GOT entry for the TLS module index.
459 unsigned int got_mod_index_offset_;
460 // True if the _TLS_MODULE_BASE_ symbol has been defined.
461 bool tls_base_symbol_defined_;
462 };
463
464 const Target::Target_info Target_i386::i386_info =
465 {
466 32, // size
467 false, // is_big_endian
468 elfcpp::EM_386, // machine_code
469 false, // has_make_symbol
470 false, // has_resolve
471 true, // has_code_fill
472 true, // is_default_stack_executable
473 '\0', // wrap_char
474 "/usr/lib/libc.so.1", // dynamic_linker
475 0x08048000, // default_text_segment_address
476 0x1000, // abi_pagesize (overridable by -z max-page-size)
477 0x1000, // common_pagesize (overridable by -z common-page-size)
478 elfcpp::SHN_UNDEF, // small_common_shndx
479 elfcpp::SHN_UNDEF, // large_common_shndx
480 0, // small_common_section_flags
481 0, // large_common_section_flags
482 NULL, // attributes_section
483 NULL // attributes_vendor
484 };
485
486 // Get the GOT section, creating it if necessary.
487
488 Output_data_got<32, false>*
489 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
490 {
491 if (this->got_ == NULL)
492 {
493 gold_assert(symtab != NULL && layout != NULL);
494
495 this->got_ = new Output_data_got<32, false>();
496
497 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
498 (elfcpp::SHF_ALLOC
499 | elfcpp::SHF_WRITE),
500 this->got_, false, true, true, false);
501
502 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
503 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
504 (elfcpp::SHF_ALLOC
505 | elfcpp::SHF_WRITE),
506 this->got_plt_, false, false, false,
507 true);
508
509 // The first three entries are reserved.
510 this->got_plt_->set_current_data_size(3 * 4);
511
512 // Those bytes can go into the relro segment.
513 layout->increase_relro(3 * 4);
514
515 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
516 this->global_offset_table_ =
517 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
518 Symbol_table::PREDEFINED,
519 this->got_plt_,
520 0, 0, elfcpp::STT_OBJECT,
521 elfcpp::STB_LOCAL,
522 elfcpp::STV_HIDDEN, 0,
523 false, false);
524 }
525
526 return this->got_;
527 }
528
529 // Get the dynamic reloc section, creating it if necessary.
530
531 Target_i386::Reloc_section*
532 Target_i386::rel_dyn_section(Layout* layout)
533 {
534 if (this->rel_dyn_ == NULL)
535 {
536 gold_assert(layout != NULL);
537 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
538 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
539 elfcpp::SHF_ALLOC, this->rel_dyn_, true,
540 false, false, false);
541 }
542 return this->rel_dyn_;
543 }
544
545 // A class to handle the PLT data.
546
547 class Output_data_plt_i386 : public Output_section_data
548 {
549 public:
550 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
551
552 Output_data_plt_i386(Layout*, Output_data_space*);
553
554 // Add an entry to the PLT.
555 void
556 add_entry(Symbol* gsym);
557
558 // Return the .rel.plt section data.
559 const Reloc_section*
560 rel_plt() const
561 { return this->rel_; }
562
563 // Return where the TLS_DESC relocations should go.
564 Reloc_section*
565 rel_tls_desc(Layout*);
566
567 protected:
568 void
569 do_adjust_output_section(Output_section* os);
570
571 // Write to a map file.
572 void
573 do_print_to_mapfile(Mapfile* mapfile) const
574 { mapfile->print_output_data(this, _("** PLT")); }
575
576 private:
577 // The size of an entry in the PLT.
578 static const int plt_entry_size = 16;
579
580 // The first entry in the PLT for an executable.
581 static unsigned char exec_first_plt_entry[plt_entry_size];
582
583 // The first entry in the PLT for a shared object.
584 static unsigned char dyn_first_plt_entry[plt_entry_size];
585
586 // Other entries in the PLT for an executable.
587 static unsigned char exec_plt_entry[plt_entry_size];
588
589 // Other entries in the PLT for a shared object.
590 static unsigned char dyn_plt_entry[plt_entry_size];
591
592 // Set the final size.
593 void
594 set_final_data_size()
595 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
596
597 // Write out the PLT data.
598 void
599 do_write(Output_file*);
600
601 // The reloc section.
602 Reloc_section* rel_;
603 // The TLS_DESC relocations, if necessary. These must follow the
604 // regular PLT relocs.
605 Reloc_section* tls_desc_rel_;
606 // The .got.plt section.
607 Output_data_space* got_plt_;
608 // The number of PLT entries.
609 unsigned int count_;
610 };
611
612 // Create the PLT section. The ordinary .got section is an argument,
613 // since we need to refer to the start. We also create our own .got
614 // section just for PLT entries.
615
616 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
617 Output_data_space* got_plt)
618 : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0)
619 {
620 this->rel_ = new Reloc_section(false);
621 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
622 elfcpp::SHF_ALLOC, this->rel_, true,
623 false, false, false);
624 }
625
626 void
627 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
628 {
629 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
630 // linker, and so do we.
631 os->set_entsize(4);
632 }
633
634 // Add an entry to the PLT.
635
636 void
637 Output_data_plt_i386::add_entry(Symbol* gsym)
638 {
639 gold_assert(!gsym->has_plt_offset());
640
641 // Note that when setting the PLT offset we skip the initial
642 // reserved PLT entry.
643 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
644
645 ++this->count_;
646
647 section_offset_type got_offset = this->got_plt_->current_data_size();
648
649 // Every PLT entry needs a GOT entry which points back to the PLT
650 // entry (this will be changed by the dynamic linker, normally
651 // lazily when the function is called).
652 this->got_plt_->set_current_data_size(got_offset + 4);
653
654 // Every PLT entry needs a reloc.
655 gsym->set_needs_dynsym_entry();
656 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
657 got_offset);
658
659 // Note that we don't need to save the symbol. The contents of the
660 // PLT are independent of which symbols are used. The symbols only
661 // appear in the relocations.
662 }
663
664 // Return where the TLS_DESC relocations should go, creating it if
665 // necessary. These follow the JUMP_SLOT relocations.
666
667 Output_data_plt_i386::Reloc_section*
668 Output_data_plt_i386::rel_tls_desc(Layout* layout)
669 {
670 if (this->tls_desc_rel_ == NULL)
671 {
672 this->tls_desc_rel_ = new Reloc_section(false);
673 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
674 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
675 true, false, false, false);
676 gold_assert(this->tls_desc_rel_->output_section() ==
677 this->rel_->output_section());
678 }
679 return this->tls_desc_rel_;
680 }
681
682 // The first entry in the PLT for an executable.
683
684 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
685 {
686 0xff, 0x35, // pushl contents of memory address
687 0, 0, 0, 0, // replaced with address of .got + 4
688 0xff, 0x25, // jmp indirect
689 0, 0, 0, 0, // replaced with address of .got + 8
690 0, 0, 0, 0 // unused
691 };
692
693 // The first entry in the PLT for a shared object.
694
695 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
696 {
697 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
698 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
699 0, 0, 0, 0 // unused
700 };
701
702 // Subsequent entries in the PLT for an executable.
703
704 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
705 {
706 0xff, 0x25, // jmp indirect
707 0, 0, 0, 0, // replaced with address of symbol in .got
708 0x68, // pushl immediate
709 0, 0, 0, 0, // replaced with offset into relocation table
710 0xe9, // jmp relative
711 0, 0, 0, 0 // replaced with offset to start of .plt
712 };
713
714 // Subsequent entries in the PLT for a shared object.
715
716 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
717 {
718 0xff, 0xa3, // jmp *offset(%ebx)
719 0, 0, 0, 0, // replaced with offset of symbol in .got
720 0x68, // pushl immediate
721 0, 0, 0, 0, // replaced with offset into relocation table
722 0xe9, // jmp relative
723 0, 0, 0, 0 // replaced with offset to start of .plt
724 };
725
726 // Write out the PLT. This uses the hand-coded instructions above,
727 // and adjusts them as needed. This is all specified by the i386 ELF
728 // Processor Supplement.
729
730 void
731 Output_data_plt_i386::do_write(Output_file* of)
732 {
733 const off_t offset = this->offset();
734 const section_size_type oview_size =
735 convert_to_section_size_type(this->data_size());
736 unsigned char* const oview = of->get_output_view(offset, oview_size);
737
738 const off_t got_file_offset = this->got_plt_->offset();
739 const section_size_type got_size =
740 convert_to_section_size_type(this->got_plt_->data_size());
741 unsigned char* const got_view = of->get_output_view(got_file_offset,
742 got_size);
743
744 unsigned char* pov = oview;
745
746 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
747 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
748
749 if (parameters->options().output_is_position_independent())
750 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
751 else
752 {
753 memcpy(pov, exec_first_plt_entry, plt_entry_size);
754 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
755 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
756 }
757 pov += plt_entry_size;
758
759 unsigned char* got_pov = got_view;
760
761 memset(got_pov, 0, 12);
762 got_pov += 12;
763
764 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
765
766 unsigned int plt_offset = plt_entry_size;
767 unsigned int plt_rel_offset = 0;
768 unsigned int got_offset = 12;
769 const unsigned int count = this->count_;
770 for (unsigned int i = 0;
771 i < count;
772 ++i,
773 pov += plt_entry_size,
774 got_pov += 4,
775 plt_offset += plt_entry_size,
776 plt_rel_offset += rel_size,
777 got_offset += 4)
778 {
779 // Set and adjust the PLT entry itself.
780
781 if (parameters->options().output_is_position_independent())
782 {
783 memcpy(pov, dyn_plt_entry, plt_entry_size);
784 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
785 }
786 else
787 {
788 memcpy(pov, exec_plt_entry, plt_entry_size);
789 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
790 (got_address
791 + got_offset));
792 }
793
794 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
795 elfcpp::Swap<32, false>::writeval(pov + 12,
796 - (plt_offset + plt_entry_size));
797
798 // Set the entry in the GOT.
799 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
800 }
801
802 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
803 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
804
805 of->write_output_view(offset, oview_size, oview);
806 of->write_output_view(got_file_offset, got_size, got_view);
807 }
808
809 // Create a PLT entry for a global symbol.
810
811 void
812 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
813 {
814 if (gsym->has_plt_offset())
815 return;
816
817 if (this->plt_ == NULL)
818 {
819 // Create the GOT sections first.
820 this->got_section(symtab, layout);
821
822 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
823 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
824 (elfcpp::SHF_ALLOC
825 | elfcpp::SHF_EXECINSTR),
826 this->plt_, false, false, false, false);
827 }
828
829 this->plt_->add_entry(gsym);
830 }
831
832 // Get the section to use for TLS_DESC relocations.
833
834 Target_i386::Reloc_section*
835 Target_i386::rel_tls_desc_section(Layout* layout) const
836 {
837 return this->plt_section()->rel_tls_desc(layout);
838 }
839
840 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
841
842 void
843 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
844 {
845 if (this->tls_base_symbol_defined_)
846 return;
847
848 Output_segment* tls_segment = layout->tls_segment();
849 if (tls_segment != NULL)
850 {
851 bool is_exec = parameters->options().output_is_executable();
852 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
853 Symbol_table::PREDEFINED,
854 tls_segment, 0, 0,
855 elfcpp::STT_TLS,
856 elfcpp::STB_LOCAL,
857 elfcpp::STV_HIDDEN, 0,
858 (is_exec
859 ? Symbol::SEGMENT_END
860 : Symbol::SEGMENT_START),
861 true);
862 }
863 this->tls_base_symbol_defined_ = true;
864 }
865
866 // Create a GOT entry for the TLS module index.
867
868 unsigned int
869 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
870 Sized_relobj<32, false>* object)
871 {
872 if (this->got_mod_index_offset_ == -1U)
873 {
874 gold_assert(symtab != NULL && layout != NULL && object != NULL);
875 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
876 Output_data_got<32, false>* got = this->got_section(symtab, layout);
877 unsigned int got_offset = got->add_constant(0);
878 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
879 got_offset);
880 got->add_constant(0);
881 this->got_mod_index_offset_ = got_offset;
882 }
883 return this->got_mod_index_offset_;
884 }
885
886 // Optimize the TLS relocation type based on what we know about the
887 // symbol. IS_FINAL is true if the final address of this symbol is
888 // known at link time.
889
890 tls::Tls_optimization
891 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
892 {
893 // If we are generating a shared library, then we can't do anything
894 // in the linker.
895 if (parameters->options().shared())
896 return tls::TLSOPT_NONE;
897
898 switch (r_type)
899 {
900 case elfcpp::R_386_TLS_GD:
901 case elfcpp::R_386_TLS_GOTDESC:
902 case elfcpp::R_386_TLS_DESC_CALL:
903 // These are General-Dynamic which permits fully general TLS
904 // access. Since we know that we are generating an executable,
905 // we can convert this to Initial-Exec. If we also know that
906 // this is a local symbol, we can further switch to Local-Exec.
907 if (is_final)
908 return tls::TLSOPT_TO_LE;
909 return tls::TLSOPT_TO_IE;
910
911 case elfcpp::R_386_TLS_LDM:
912 // This is Local-Dynamic, which refers to a local symbol in the
913 // dynamic TLS block. Since we know that we generating an
914 // executable, we can switch to Local-Exec.
915 return tls::TLSOPT_TO_LE;
916
917 case elfcpp::R_386_TLS_LDO_32:
918 // Another type of Local-Dynamic relocation.
919 return tls::TLSOPT_TO_LE;
920
921 case elfcpp::R_386_TLS_IE:
922 case elfcpp::R_386_TLS_GOTIE:
923 case elfcpp::R_386_TLS_IE_32:
924 // These are Initial-Exec relocs which get the thread offset
925 // from the GOT. If we know that we are linking against the
926 // local symbol, we can switch to Local-Exec, which links the
927 // thread offset into the instruction.
928 if (is_final)
929 return tls::TLSOPT_TO_LE;
930 return tls::TLSOPT_NONE;
931
932 case elfcpp::R_386_TLS_LE:
933 case elfcpp::R_386_TLS_LE_32:
934 // When we already have Local-Exec, there is nothing further we
935 // can do.
936 return tls::TLSOPT_NONE;
937
938 default:
939 gold_unreachable();
940 }
941 }
942
943 // Report an unsupported relocation against a local symbol.
944
945 void
946 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
947 unsigned int r_type)
948 {
949 gold_error(_("%s: unsupported reloc %u against local symbol"),
950 object->name().c_str(), r_type);
951 }
952
953 // Scan a relocation for a local symbol.
954
955 inline void
956 Target_i386::Scan::local(Symbol_table* symtab,
957 Layout* layout,
958 Target_i386* target,
959 Sized_relobj<32, false>* object,
960 unsigned int data_shndx,
961 Output_section* output_section,
962 const elfcpp::Rel<32, false>& reloc,
963 unsigned int r_type,
964 const elfcpp::Sym<32, false>& lsym)
965 {
966 switch (r_type)
967 {
968 case elfcpp::R_386_NONE:
969 case elfcpp::R_386_GNU_VTINHERIT:
970 case elfcpp::R_386_GNU_VTENTRY:
971 break;
972
973 case elfcpp::R_386_32:
974 // If building a shared library (or a position-independent
975 // executable), we need to create a dynamic relocation for
976 // this location. The relocation applied at link time will
977 // apply the link-time value, so we flag the location with
978 // an R_386_RELATIVE relocation so the dynamic loader can
979 // relocate it easily.
980 if (parameters->options().output_is_position_independent())
981 {
982 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
983 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
984 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
985 output_section, data_shndx,
986 reloc.get_r_offset());
987 }
988 break;
989
990 case elfcpp::R_386_16:
991 case elfcpp::R_386_8:
992 // If building a shared library (or a position-independent
993 // executable), we need to create a dynamic relocation for
994 // this location. Because the addend needs to remain in the
995 // data section, we need to be careful not to apply this
996 // relocation statically.
997 if (parameters->options().output_is_position_independent())
998 {
999 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1000 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1001 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1002 rel_dyn->add_local(object, r_sym, r_type, output_section,
1003 data_shndx, reloc.get_r_offset());
1004 else
1005 {
1006 gold_assert(lsym.get_st_value() == 0);
1007 unsigned int shndx = lsym.get_st_shndx();
1008 bool is_ordinary;
1009 shndx = object->adjust_sym_shndx(r_sym, shndx,
1010 &is_ordinary);
1011 if (!is_ordinary)
1012 object->error(_("section symbol %u has bad shndx %u"),
1013 r_sym, shndx);
1014 else
1015 rel_dyn->add_local_section(object, shndx,
1016 r_type, output_section,
1017 data_shndx, reloc.get_r_offset());
1018 }
1019 }
1020 break;
1021
1022 case elfcpp::R_386_PC32:
1023 case elfcpp::R_386_PC16:
1024 case elfcpp::R_386_PC8:
1025 break;
1026
1027 case elfcpp::R_386_PLT32:
1028 // Since we know this is a local symbol, we can handle this as a
1029 // PC32 reloc.
1030 break;
1031
1032 case elfcpp::R_386_GOTOFF:
1033 case elfcpp::R_386_GOTPC:
1034 // We need a GOT section.
1035 target->got_section(symtab, layout);
1036 break;
1037
1038 case elfcpp::R_386_GOT32:
1039 {
1040 // The symbol requires a GOT entry.
1041 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1042 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1043 if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1044 {
1045 // If we are generating a shared object, we need to add a
1046 // dynamic RELATIVE relocation for this symbol's GOT entry.
1047 if (parameters->options().output_is_position_independent())
1048 {
1049 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1050 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1051 rel_dyn->add_local_relative(
1052 object, r_sym, elfcpp::R_386_RELATIVE, got,
1053 object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
1054 }
1055 }
1056 }
1057 break;
1058
1059 // These are relocations which should only be seen by the
1060 // dynamic linker, and should never be seen here.
1061 case elfcpp::R_386_COPY:
1062 case elfcpp::R_386_GLOB_DAT:
1063 case elfcpp::R_386_JUMP_SLOT:
1064 case elfcpp::R_386_RELATIVE:
1065 case elfcpp::R_386_TLS_TPOFF:
1066 case elfcpp::R_386_TLS_DTPMOD32:
1067 case elfcpp::R_386_TLS_DTPOFF32:
1068 case elfcpp::R_386_TLS_TPOFF32:
1069 case elfcpp::R_386_TLS_DESC:
1070 gold_error(_("%s: unexpected reloc %u in object file"),
1071 object->name().c_str(), r_type);
1072 break;
1073
1074 // These are initial TLS relocs, which are expected when
1075 // linking.
1076 case elfcpp::R_386_TLS_GD: // Global-dynamic
1077 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1078 case elfcpp::R_386_TLS_DESC_CALL:
1079 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1080 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1081 case elfcpp::R_386_TLS_IE: // Initial-exec
1082 case elfcpp::R_386_TLS_IE_32:
1083 case elfcpp::R_386_TLS_GOTIE:
1084 case elfcpp::R_386_TLS_LE: // Local-exec
1085 case elfcpp::R_386_TLS_LE_32:
1086 {
1087 bool output_is_shared = parameters->options().shared();
1088 const tls::Tls_optimization optimized_type
1089 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1090 switch (r_type)
1091 {
1092 case elfcpp::R_386_TLS_GD: // Global-dynamic
1093 if (optimized_type == tls::TLSOPT_NONE)
1094 {
1095 // Create a pair of GOT entries for the module index and
1096 // dtv-relative offset.
1097 Output_data_got<32, false>* got
1098 = target->got_section(symtab, layout);
1099 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1100 unsigned int shndx = lsym.get_st_shndx();
1101 bool is_ordinary;
1102 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1103 if (!is_ordinary)
1104 object->error(_("local symbol %u has bad shndx %u"),
1105 r_sym, shndx);
1106 else
1107 got->add_local_pair_with_rel(object, r_sym, shndx,
1108 GOT_TYPE_TLS_PAIR,
1109 target->rel_dyn_section(layout),
1110 elfcpp::R_386_TLS_DTPMOD32, 0);
1111 }
1112 else if (optimized_type != tls::TLSOPT_TO_LE)
1113 unsupported_reloc_local(object, r_type);
1114 break;
1115
1116 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1117 target->define_tls_base_symbol(symtab, layout);
1118 if (optimized_type == tls::TLSOPT_NONE)
1119 {
1120 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1121 Output_data_got<32, false>* got
1122 = target->got_section(symtab, layout);
1123 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1124 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1125 {
1126 unsigned int got_offset = got->add_constant(0);
1127 // The local symbol value is stored in the second
1128 // GOT entry.
1129 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1130 // That set the GOT offset of the local symbol to
1131 // point to the second entry, but we want it to
1132 // point to the first.
1133 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1134 got_offset);
1135 Reloc_section* rt = target->rel_tls_desc_section(layout);
1136 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1137 }
1138 }
1139 else if (optimized_type != tls::TLSOPT_TO_LE)
1140 unsupported_reloc_local(object, r_type);
1141 break;
1142
1143 case elfcpp::R_386_TLS_DESC_CALL:
1144 break;
1145
1146 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1147 if (optimized_type == tls::TLSOPT_NONE)
1148 {
1149 // Create a GOT entry for the module index.
1150 target->got_mod_index_entry(symtab, layout, object);
1151 }
1152 else if (optimized_type != tls::TLSOPT_TO_LE)
1153 unsupported_reloc_local(object, r_type);
1154 break;
1155
1156 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1157 break;
1158
1159 case elfcpp::R_386_TLS_IE: // Initial-exec
1160 case elfcpp::R_386_TLS_IE_32:
1161 case elfcpp::R_386_TLS_GOTIE:
1162 layout->set_has_static_tls();
1163 if (optimized_type == tls::TLSOPT_NONE)
1164 {
1165 // For the R_386_TLS_IE relocation, we need to create a
1166 // dynamic relocation when building a shared library.
1167 if (r_type == elfcpp::R_386_TLS_IE
1168 && parameters->options().shared())
1169 {
1170 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1171 unsigned int r_sym
1172 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1173 rel_dyn->add_local_relative(object, r_sym,
1174 elfcpp::R_386_RELATIVE,
1175 output_section, data_shndx,
1176 reloc.get_r_offset());
1177 }
1178 // Create a GOT entry for the tp-relative offset.
1179 Output_data_got<32, false>* got
1180 = target->got_section(symtab, layout);
1181 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1182 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1183 ? elfcpp::R_386_TLS_TPOFF32
1184 : elfcpp::R_386_TLS_TPOFF);
1185 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1186 ? GOT_TYPE_TLS_OFFSET
1187 : GOT_TYPE_TLS_NOFFSET);
1188 got->add_local_with_rel(object, r_sym, got_type,
1189 target->rel_dyn_section(layout),
1190 dyn_r_type);
1191 }
1192 else if (optimized_type != tls::TLSOPT_TO_LE)
1193 unsupported_reloc_local(object, r_type);
1194 break;
1195
1196 case elfcpp::R_386_TLS_LE: // Local-exec
1197 case elfcpp::R_386_TLS_LE_32:
1198 layout->set_has_static_tls();
1199 if (output_is_shared)
1200 {
1201 // We need to create a dynamic relocation.
1202 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1203 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1204 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1205 ? elfcpp::R_386_TLS_TPOFF32
1206 : elfcpp::R_386_TLS_TPOFF);
1207 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1208 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1209 data_shndx, reloc.get_r_offset());
1210 }
1211 break;
1212
1213 default:
1214 gold_unreachable();
1215 }
1216 }
1217 break;
1218
1219 case elfcpp::R_386_32PLT:
1220 case elfcpp::R_386_TLS_GD_32:
1221 case elfcpp::R_386_TLS_GD_PUSH:
1222 case elfcpp::R_386_TLS_GD_CALL:
1223 case elfcpp::R_386_TLS_GD_POP:
1224 case elfcpp::R_386_TLS_LDM_32:
1225 case elfcpp::R_386_TLS_LDM_PUSH:
1226 case elfcpp::R_386_TLS_LDM_CALL:
1227 case elfcpp::R_386_TLS_LDM_POP:
1228 case elfcpp::R_386_USED_BY_INTEL_200:
1229 default:
1230 unsupported_reloc_local(object, r_type);
1231 break;
1232 }
1233 }
1234
1235 // Report an unsupported relocation against a global symbol.
1236
1237 void
1238 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1239 unsigned int r_type,
1240 Symbol* gsym)
1241 {
1242 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1243 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1244 }
1245
1246 inline bool
1247 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
1248 {
1249 switch (r_type)
1250 {
1251 case elfcpp::R_386_32:
1252 case elfcpp::R_386_16:
1253 case elfcpp::R_386_8:
1254 case elfcpp::R_386_GOTOFF:
1255 case elfcpp::R_386_GOT32:
1256 {
1257 return true;
1258 }
1259 default:
1260 return false;
1261 }
1262 return false;
1263 }
1264
1265 inline bool
1266 Target_i386::Scan::local_reloc_may_be_function_pointer(
1267 Symbol_table* ,
1268 Layout* ,
1269 Target_i386* ,
1270 Sized_relobj<32, false>* ,
1271 unsigned int ,
1272 Output_section* ,
1273 const elfcpp::Rel<32, false>& ,
1274 unsigned int r_type,
1275 const elfcpp::Sym<32, false>&)
1276 {
1277 return possible_function_pointer_reloc(r_type);
1278 }
1279
1280 inline bool
1281 Target_i386::Scan::global_reloc_may_be_function_pointer(
1282 Symbol_table* ,
1283 Layout* ,
1284 Target_i386* ,
1285 Sized_relobj<32, false>* ,
1286 unsigned int ,
1287 Output_section* ,
1288 const elfcpp::Rel<32, false>& ,
1289 unsigned int r_type,
1290 Symbol*)
1291 {
1292 return possible_function_pointer_reloc(r_type);
1293 }
1294
1295 // Scan a relocation for a global symbol.
1296
1297 inline void
1298 Target_i386::Scan::global(Symbol_table* symtab,
1299 Layout* layout,
1300 Target_i386* target,
1301 Sized_relobj<32, false>* object,
1302 unsigned int data_shndx,
1303 Output_section* output_section,
1304 const elfcpp::Rel<32, false>& reloc,
1305 unsigned int r_type,
1306 Symbol* gsym)
1307 {
1308 switch (r_type)
1309 {
1310 case elfcpp::R_386_NONE:
1311 case elfcpp::R_386_GNU_VTINHERIT:
1312 case elfcpp::R_386_GNU_VTENTRY:
1313 break;
1314
1315 case elfcpp::R_386_32:
1316 case elfcpp::R_386_16:
1317 case elfcpp::R_386_8:
1318 {
1319 // Make a PLT entry if necessary.
1320 if (gsym->needs_plt_entry())
1321 {
1322 target->make_plt_entry(symtab, layout, gsym);
1323 // Since this is not a PC-relative relocation, we may be
1324 // taking the address of a function. In that case we need to
1325 // set the entry in the dynamic symbol table to the address of
1326 // the PLT entry.
1327 if (gsym->is_from_dynobj() && !parameters->options().shared())
1328 gsym->set_needs_dynsym_value();
1329 }
1330 // Make a dynamic relocation if necessary.
1331 if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1332 {
1333 if (gsym->may_need_copy_reloc())
1334 {
1335 target->copy_reloc(symtab, layout, object,
1336 data_shndx, output_section, gsym, reloc);
1337 }
1338 else if (r_type == elfcpp::R_386_32
1339 && gsym->can_use_relative_reloc(false))
1340 {
1341 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1342 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1343 output_section, object,
1344 data_shndx, reloc.get_r_offset());
1345 }
1346 else
1347 {
1348 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1349 rel_dyn->add_global(gsym, r_type, output_section, object,
1350 data_shndx, reloc.get_r_offset());
1351 }
1352 }
1353 }
1354 break;
1355
1356 case elfcpp::R_386_PC32:
1357 case elfcpp::R_386_PC16:
1358 case elfcpp::R_386_PC8:
1359 {
1360 // Make a PLT entry if necessary.
1361 if (gsym->needs_plt_entry())
1362 {
1363 // These relocations are used for function calls only in
1364 // non-PIC code. For a 32-bit relocation in a shared library,
1365 // we'll need a text relocation anyway, so we can skip the
1366 // PLT entry and let the dynamic linker bind the call directly
1367 // to the target. For smaller relocations, we should use a
1368 // PLT entry to ensure that the call can reach.
1369 if (!parameters->options().shared()
1370 || r_type != elfcpp::R_386_PC32)
1371 target->make_plt_entry(symtab, layout, gsym);
1372 }
1373 // Make a dynamic relocation if necessary.
1374 int flags = Symbol::NON_PIC_REF;
1375 if (gsym->is_func())
1376 flags |= Symbol::FUNCTION_CALL;
1377 if (gsym->needs_dynamic_reloc(flags))
1378 {
1379 if (gsym->may_need_copy_reloc())
1380 {
1381 target->copy_reloc(symtab, layout, object,
1382 data_shndx, output_section, gsym, reloc);
1383 }
1384 else
1385 {
1386 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1387 rel_dyn->add_global(gsym, r_type, output_section, object,
1388 data_shndx, reloc.get_r_offset());
1389 }
1390 }
1391 }
1392 break;
1393
1394 case elfcpp::R_386_GOT32:
1395 {
1396 // The symbol requires a GOT entry.
1397 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1398 if (gsym->final_value_is_known())
1399 got->add_global(gsym, GOT_TYPE_STANDARD);
1400 else
1401 {
1402 // If this symbol is not fully resolved, we need to add a
1403 // GOT entry with a dynamic relocation.
1404 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1405 if (gsym->is_from_dynobj()
1406 || gsym->is_undefined()
1407 || gsym->is_preemptible())
1408 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1409 rel_dyn, elfcpp::R_386_GLOB_DAT);
1410 else
1411 {
1412 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1413 rel_dyn->add_global_relative(
1414 gsym, elfcpp::R_386_RELATIVE, got,
1415 gsym->got_offset(GOT_TYPE_STANDARD));
1416 }
1417 }
1418 }
1419 break;
1420
1421 case elfcpp::R_386_PLT32:
1422 // If the symbol is fully resolved, this is just a PC32 reloc.
1423 // Otherwise we need a PLT entry.
1424 if (gsym->final_value_is_known())
1425 break;
1426 // If building a shared library, we can also skip the PLT entry
1427 // if the symbol is defined in the output file and is protected
1428 // or hidden.
1429 if (gsym->is_defined()
1430 && !gsym->is_from_dynobj()
1431 && !gsym->is_preemptible())
1432 break;
1433 target->make_plt_entry(symtab, layout, gsym);
1434 break;
1435
1436 case elfcpp::R_386_GOTOFF:
1437 case elfcpp::R_386_GOTPC:
1438 // We need a GOT section.
1439 target->got_section(symtab, layout);
1440 break;
1441
1442 // These are relocations which should only be seen by the
1443 // dynamic linker, and should never be seen here.
1444 case elfcpp::R_386_COPY:
1445 case elfcpp::R_386_GLOB_DAT:
1446 case elfcpp::R_386_JUMP_SLOT:
1447 case elfcpp::R_386_RELATIVE:
1448 case elfcpp::R_386_TLS_TPOFF:
1449 case elfcpp::R_386_TLS_DTPMOD32:
1450 case elfcpp::R_386_TLS_DTPOFF32:
1451 case elfcpp::R_386_TLS_TPOFF32:
1452 case elfcpp::R_386_TLS_DESC:
1453 gold_error(_("%s: unexpected reloc %u in object file"),
1454 object->name().c_str(), r_type);
1455 break;
1456
1457 // These are initial tls relocs, which are expected when
1458 // linking.
1459 case elfcpp::R_386_TLS_GD: // Global-dynamic
1460 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1461 case elfcpp::R_386_TLS_DESC_CALL:
1462 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1463 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1464 case elfcpp::R_386_TLS_IE: // Initial-exec
1465 case elfcpp::R_386_TLS_IE_32:
1466 case elfcpp::R_386_TLS_GOTIE:
1467 case elfcpp::R_386_TLS_LE: // Local-exec
1468 case elfcpp::R_386_TLS_LE_32:
1469 {
1470 const bool is_final = gsym->final_value_is_known();
1471 const tls::Tls_optimization optimized_type
1472 = Target_i386::optimize_tls_reloc(is_final, r_type);
1473 switch (r_type)
1474 {
1475 case elfcpp::R_386_TLS_GD: // Global-dynamic
1476 if (optimized_type == tls::TLSOPT_NONE)
1477 {
1478 // Create a pair of GOT entries for the module index and
1479 // dtv-relative offset.
1480 Output_data_got<32, false>* got
1481 = target->got_section(symtab, layout);
1482 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1483 target->rel_dyn_section(layout),
1484 elfcpp::R_386_TLS_DTPMOD32,
1485 elfcpp::R_386_TLS_DTPOFF32);
1486 }
1487 else if (optimized_type == tls::TLSOPT_TO_IE)
1488 {
1489 // Create a GOT entry for the tp-relative offset.
1490 Output_data_got<32, false>* got
1491 = target->got_section(symtab, layout);
1492 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1493 target->rel_dyn_section(layout),
1494 elfcpp::R_386_TLS_TPOFF);
1495 }
1496 else if (optimized_type != tls::TLSOPT_TO_LE)
1497 unsupported_reloc_global(object, r_type, gsym);
1498 break;
1499
1500 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1501 target->define_tls_base_symbol(symtab, layout);
1502 if (optimized_type == tls::TLSOPT_NONE)
1503 {
1504 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1505 Output_data_got<32, false>* got
1506 = target->got_section(symtab, layout);
1507 Reloc_section* rt = target->rel_tls_desc_section(layout);
1508 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
1509 elfcpp::R_386_TLS_DESC, 0);
1510 }
1511 else if (optimized_type == tls::TLSOPT_TO_IE)
1512 {
1513 // Create a GOT entry for the tp-relative offset.
1514 Output_data_got<32, false>* got
1515 = target->got_section(symtab, layout);
1516 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1517 target->rel_dyn_section(layout),
1518 elfcpp::R_386_TLS_TPOFF);
1519 }
1520 else if (optimized_type != tls::TLSOPT_TO_LE)
1521 unsupported_reloc_global(object, r_type, gsym);
1522 break;
1523
1524 case elfcpp::R_386_TLS_DESC_CALL:
1525 break;
1526
1527 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1528 if (optimized_type == tls::TLSOPT_NONE)
1529 {
1530 // Create a GOT entry for the module index.
1531 target->got_mod_index_entry(symtab, layout, object);
1532 }
1533 else if (optimized_type != tls::TLSOPT_TO_LE)
1534 unsupported_reloc_global(object, r_type, gsym);
1535 break;
1536
1537 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1538 break;
1539
1540 case elfcpp::R_386_TLS_IE: // Initial-exec
1541 case elfcpp::R_386_TLS_IE_32:
1542 case elfcpp::R_386_TLS_GOTIE:
1543 layout->set_has_static_tls();
1544 if (optimized_type == tls::TLSOPT_NONE)
1545 {
1546 // For the R_386_TLS_IE relocation, we need to create a
1547 // dynamic relocation when building a shared library.
1548 if (r_type == elfcpp::R_386_TLS_IE
1549 && parameters->options().shared())
1550 {
1551 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1552 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1553 output_section, object,
1554 data_shndx,
1555 reloc.get_r_offset());
1556 }
1557 // Create a GOT entry for the tp-relative offset.
1558 Output_data_got<32, false>* got
1559 = target->got_section(symtab, layout);
1560 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1561 ? elfcpp::R_386_TLS_TPOFF32
1562 : elfcpp::R_386_TLS_TPOFF);
1563 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1564 ? GOT_TYPE_TLS_OFFSET
1565 : GOT_TYPE_TLS_NOFFSET);
1566 got->add_global_with_rel(gsym, got_type,
1567 target->rel_dyn_section(layout),
1568 dyn_r_type);
1569 }
1570 else if (optimized_type != tls::TLSOPT_TO_LE)
1571 unsupported_reloc_global(object, r_type, gsym);
1572 break;
1573
1574 case elfcpp::R_386_TLS_LE: // Local-exec
1575 case elfcpp::R_386_TLS_LE_32:
1576 layout->set_has_static_tls();
1577 if (parameters->options().shared())
1578 {
1579 // We need to create a dynamic relocation.
1580 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1581 ? elfcpp::R_386_TLS_TPOFF32
1582 : elfcpp::R_386_TLS_TPOFF);
1583 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1584 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1585 data_shndx, reloc.get_r_offset());
1586 }
1587 break;
1588
1589 default:
1590 gold_unreachable();
1591 }
1592 }
1593 break;
1594
1595 case elfcpp::R_386_32PLT:
1596 case elfcpp::R_386_TLS_GD_32:
1597 case elfcpp::R_386_TLS_GD_PUSH:
1598 case elfcpp::R_386_TLS_GD_CALL:
1599 case elfcpp::R_386_TLS_GD_POP:
1600 case elfcpp::R_386_TLS_LDM_32:
1601 case elfcpp::R_386_TLS_LDM_PUSH:
1602 case elfcpp::R_386_TLS_LDM_CALL:
1603 case elfcpp::R_386_TLS_LDM_POP:
1604 case elfcpp::R_386_USED_BY_INTEL_200:
1605 default:
1606 unsupported_reloc_global(object, r_type, gsym);
1607 break;
1608 }
1609 }
1610
1611 // Process relocations for gc.
1612
1613 void
1614 Target_i386::gc_process_relocs(Symbol_table* symtab,
1615 Layout* layout,
1616 Sized_relobj<32, false>* object,
1617 unsigned int data_shndx,
1618 unsigned int,
1619 const unsigned char* prelocs,
1620 size_t reloc_count,
1621 Output_section* output_section,
1622 bool needs_special_offset_handling,
1623 size_t local_symbol_count,
1624 const unsigned char* plocal_symbols)
1625 {
1626 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1627 Target_i386::Scan>(
1628 symtab,
1629 layout,
1630 this,
1631 object,
1632 data_shndx,
1633 prelocs,
1634 reloc_count,
1635 output_section,
1636 needs_special_offset_handling,
1637 local_symbol_count,
1638 plocal_symbols);
1639 }
1640
1641 // Scan relocations for a section.
1642
1643 void
1644 Target_i386::scan_relocs(Symbol_table* symtab,
1645 Layout* layout,
1646 Sized_relobj<32, false>* object,
1647 unsigned int data_shndx,
1648 unsigned int sh_type,
1649 const unsigned char* prelocs,
1650 size_t reloc_count,
1651 Output_section* output_section,
1652 bool needs_special_offset_handling,
1653 size_t local_symbol_count,
1654 const unsigned char* plocal_symbols)
1655 {
1656 if (sh_type == elfcpp::SHT_RELA)
1657 {
1658 gold_error(_("%s: unsupported RELA reloc section"),
1659 object->name().c_str());
1660 return;
1661 }
1662
1663 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1664 Target_i386::Scan>(
1665 symtab,
1666 layout,
1667 this,
1668 object,
1669 data_shndx,
1670 prelocs,
1671 reloc_count,
1672 output_section,
1673 needs_special_offset_handling,
1674 local_symbol_count,
1675 plocal_symbols);
1676 }
1677
1678 // Finalize the sections.
1679
1680 void
1681 Target_i386::do_finalize_sections(
1682 Layout* layout,
1683 const Input_objects*,
1684 Symbol_table* symtab)
1685 {
1686 const Reloc_section* rel_plt = (this->plt_ == NULL
1687 ? NULL
1688 : this->plt_->rel_plt());
1689 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
1690 this->rel_dyn_, true, false);
1691
1692 // Emit any relocs we saved in an attempt to avoid generating COPY
1693 // relocs.
1694 if (this->copy_relocs_.any_saved_relocs())
1695 this->copy_relocs_.emit(this->rel_dyn_section(layout));
1696
1697 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1698 // the .got.plt section.
1699 Symbol* sym = this->global_offset_table_;
1700 if (sym != NULL)
1701 {
1702 uint32_t data_size = this->got_plt_->current_data_size();
1703 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
1704 }
1705 }
1706
1707 // Return whether a direct absolute static relocation needs to be applied.
1708 // In cases where Scan::local() or Scan::global() has created
1709 // a dynamic relocation other than R_386_RELATIVE, the addend
1710 // of the relocation is carried in the data, and we must not
1711 // apply the static relocation.
1712
1713 inline bool
1714 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1715 int ref_flags,
1716 bool is_32bit,
1717 Output_section* output_section)
1718 {
1719 // If the output section is not allocated, then we didn't call
1720 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1721 // the reloc here.
1722 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1723 return true;
1724
1725 // For local symbols, we will have created a non-RELATIVE dynamic
1726 // relocation only if (a) the output is position independent,
1727 // (b) the relocation is absolute (not pc- or segment-relative), and
1728 // (c) the relocation is not 32 bits wide.
1729 if (gsym == NULL)
1730 return !(parameters->options().output_is_position_independent()
1731 && (ref_flags & Symbol::ABSOLUTE_REF)
1732 && !is_32bit);
1733
1734 // For global symbols, we use the same helper routines used in the
1735 // scan pass. If we did not create a dynamic relocation, or if we
1736 // created a RELATIVE dynamic relocation, we should apply the static
1737 // relocation.
1738 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1739 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1740 && gsym->can_use_relative_reloc(ref_flags
1741 & Symbol::FUNCTION_CALL);
1742 return !has_dyn || is_rel;
1743 }
1744
1745 // Perform a relocation.
1746
1747 inline bool
1748 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1749 Target_i386* target,
1750 Output_section *output_section,
1751 size_t relnum,
1752 const elfcpp::Rel<32, false>& rel,
1753 unsigned int r_type,
1754 const Sized_symbol<32>* gsym,
1755 const Symbol_value<32>* psymval,
1756 unsigned char* view,
1757 elfcpp::Elf_types<32>::Elf_Addr address,
1758 section_size_type view_size)
1759 {
1760 if (this->skip_call_tls_get_addr_)
1761 {
1762 if ((r_type != elfcpp::R_386_PLT32
1763 && r_type != elfcpp::R_386_PC32)
1764 || gsym == NULL
1765 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1766 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1767 _("missing expected TLS relocation"));
1768 else
1769 {
1770 this->skip_call_tls_get_addr_ = false;
1771 return false;
1772 }
1773 }
1774
1775 // Pick the value to use for symbols defined in shared objects.
1776 Symbol_value<32> symval;
1777 if (gsym != NULL
1778 && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1779 || r_type == elfcpp::R_386_PC16
1780 || r_type == elfcpp::R_386_PC32))
1781 {
1782 symval.set_output_value(target->plt_section()->address()
1783 + gsym->plt_offset());
1784 psymval = &symval;
1785 }
1786
1787 const Sized_relobj<32, false>* object = relinfo->object;
1788
1789 // Get the GOT offset if needed.
1790 // The GOT pointer points to the end of the GOT section.
1791 // We need to subtract the size of the GOT section to get
1792 // the actual offset to use in the relocation.
1793 bool have_got_offset = false;
1794 unsigned int got_offset = 0;
1795 switch (r_type)
1796 {
1797 case elfcpp::R_386_GOT32:
1798 if (gsym != NULL)
1799 {
1800 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1801 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1802 - target->got_size());
1803 }
1804 else
1805 {
1806 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1807 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1808 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1809 - target->got_size());
1810 }
1811 have_got_offset = true;
1812 break;
1813
1814 default:
1815 break;
1816 }
1817
1818 switch (r_type)
1819 {
1820 case elfcpp::R_386_NONE:
1821 case elfcpp::R_386_GNU_VTINHERIT:
1822 case elfcpp::R_386_GNU_VTENTRY:
1823 break;
1824
1825 case elfcpp::R_386_32:
1826 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1827 output_section))
1828 Relocate_functions<32, false>::rel32(view, object, psymval);
1829 break;
1830
1831 case elfcpp::R_386_PC32:
1832 {
1833 int ref_flags = Symbol::NON_PIC_REF;
1834 if (gsym != NULL && gsym->is_func())
1835 ref_flags |= Symbol::FUNCTION_CALL;
1836 if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1837 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1838 }
1839 break;
1840
1841 case elfcpp::R_386_16:
1842 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1843 output_section))
1844 Relocate_functions<32, false>::rel16(view, object, psymval);
1845 break;
1846
1847 case elfcpp::R_386_PC16:
1848 {
1849 int ref_flags = Symbol::NON_PIC_REF;
1850 if (gsym != NULL && gsym->is_func())
1851 ref_flags |= Symbol::FUNCTION_CALL;
1852 if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1853 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1854 }
1855 break;
1856
1857 case elfcpp::R_386_8:
1858 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1859 output_section))
1860 Relocate_functions<32, false>::rel8(view, object, psymval);
1861 break;
1862
1863 case elfcpp::R_386_PC8:
1864 {
1865 int ref_flags = Symbol::NON_PIC_REF;
1866 if (gsym != NULL && gsym->is_func())
1867 ref_flags |= Symbol::FUNCTION_CALL;
1868 if (should_apply_static_reloc(gsym, ref_flags, false,
1869 output_section))
1870 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1871 }
1872 break;
1873
1874 case elfcpp::R_386_PLT32:
1875 gold_assert(gsym == NULL
1876 || gsym->has_plt_offset()
1877 || gsym->final_value_is_known()
1878 || (gsym->is_defined()
1879 && !gsym->is_from_dynobj()
1880 && !gsym->is_preemptible()));
1881 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1882 break;
1883
1884 case elfcpp::R_386_GOT32:
1885 gold_assert(have_got_offset);
1886 Relocate_functions<32, false>::rel32(view, got_offset);
1887 break;
1888
1889 case elfcpp::R_386_GOTOFF:
1890 {
1891 elfcpp::Elf_types<32>::Elf_Addr value;
1892 value = (psymval->value(object, 0)
1893 - target->got_plt_section()->address());
1894 Relocate_functions<32, false>::rel32(view, value);
1895 }
1896 break;
1897
1898 case elfcpp::R_386_GOTPC:
1899 {
1900 elfcpp::Elf_types<32>::Elf_Addr value;
1901 value = target->got_plt_section()->address();
1902 Relocate_functions<32, false>::pcrel32(view, value, address);
1903 }
1904 break;
1905
1906 case elfcpp::R_386_COPY:
1907 case elfcpp::R_386_GLOB_DAT:
1908 case elfcpp::R_386_JUMP_SLOT:
1909 case elfcpp::R_386_RELATIVE:
1910 // These are outstanding tls relocs, which are unexpected when
1911 // linking.
1912 case elfcpp::R_386_TLS_TPOFF:
1913 case elfcpp::R_386_TLS_DTPMOD32:
1914 case elfcpp::R_386_TLS_DTPOFF32:
1915 case elfcpp::R_386_TLS_TPOFF32:
1916 case elfcpp::R_386_TLS_DESC:
1917 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1918 _("unexpected reloc %u in object file"),
1919 r_type);
1920 break;
1921
1922 // These are initial tls relocs, which are expected when
1923 // linking.
1924 case elfcpp::R_386_TLS_GD: // Global-dynamic
1925 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1926 case elfcpp::R_386_TLS_DESC_CALL:
1927 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1928 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1929 case elfcpp::R_386_TLS_IE: // Initial-exec
1930 case elfcpp::R_386_TLS_IE_32:
1931 case elfcpp::R_386_TLS_GOTIE:
1932 case elfcpp::R_386_TLS_LE: // Local-exec
1933 case elfcpp::R_386_TLS_LE_32:
1934 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1935 view, address, view_size);
1936 break;
1937
1938 case elfcpp::R_386_32PLT:
1939 case elfcpp::R_386_TLS_GD_32:
1940 case elfcpp::R_386_TLS_GD_PUSH:
1941 case elfcpp::R_386_TLS_GD_CALL:
1942 case elfcpp::R_386_TLS_GD_POP:
1943 case elfcpp::R_386_TLS_LDM_32:
1944 case elfcpp::R_386_TLS_LDM_PUSH:
1945 case elfcpp::R_386_TLS_LDM_CALL:
1946 case elfcpp::R_386_TLS_LDM_POP:
1947 case elfcpp::R_386_USED_BY_INTEL_200:
1948 default:
1949 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1950 _("unsupported reloc %u"),
1951 r_type);
1952 break;
1953 }
1954
1955 return true;
1956 }
1957
1958 // Perform a TLS relocation.
1959
1960 inline void
1961 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1962 Target_i386* target,
1963 size_t relnum,
1964 const elfcpp::Rel<32, false>& rel,
1965 unsigned int r_type,
1966 const Sized_symbol<32>* gsym,
1967 const Symbol_value<32>* psymval,
1968 unsigned char* view,
1969 elfcpp::Elf_types<32>::Elf_Addr,
1970 section_size_type view_size)
1971 {
1972 Output_segment* tls_segment = relinfo->layout->tls_segment();
1973
1974 const Sized_relobj<32, false>* object = relinfo->object;
1975
1976 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1977
1978 const bool is_final = (gsym == NULL
1979 ? !parameters->options().shared()
1980 : gsym->final_value_is_known());
1981 const tls::Tls_optimization optimized_type
1982 = Target_i386::optimize_tls_reloc(is_final, r_type);
1983 switch (r_type)
1984 {
1985 case elfcpp::R_386_TLS_GD: // Global-dynamic
1986 if (optimized_type == tls::TLSOPT_TO_LE)
1987 {
1988 gold_assert(tls_segment != NULL);
1989 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1990 rel, r_type, value, view,
1991 view_size);
1992 break;
1993 }
1994 else
1995 {
1996 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1997 ? GOT_TYPE_TLS_NOFFSET
1998 : GOT_TYPE_TLS_PAIR);
1999 unsigned int got_offset;
2000 if (gsym != NULL)
2001 {
2002 gold_assert(gsym->has_got_offset(got_type));
2003 got_offset = gsym->got_offset(got_type) - target->got_size();
2004 }
2005 else
2006 {
2007 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2008 gold_assert(object->local_has_got_offset(r_sym, got_type));
2009 got_offset = (object->local_got_offset(r_sym, got_type)
2010 - target->got_size());
2011 }
2012 if (optimized_type == tls::TLSOPT_TO_IE)
2013 {
2014 gold_assert(tls_segment != NULL);
2015 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2016 got_offset, view, view_size);
2017 break;
2018 }
2019 else if (optimized_type == tls::TLSOPT_NONE)
2020 {
2021 // Relocate the field with the offset of the pair of GOT
2022 // entries.
2023 Relocate_functions<32, false>::rel32(view, got_offset);
2024 break;
2025 }
2026 }
2027 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2028 _("unsupported reloc %u"),
2029 r_type);
2030 break;
2031
2032 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2033 case elfcpp::R_386_TLS_DESC_CALL:
2034 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2035 if (optimized_type == tls::TLSOPT_TO_LE)
2036 {
2037 gold_assert(tls_segment != NULL);
2038 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2039 rel, r_type, value, view,
2040 view_size);
2041 break;
2042 }
2043 else
2044 {
2045 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2046 ? GOT_TYPE_TLS_NOFFSET
2047 : GOT_TYPE_TLS_DESC);
2048 unsigned int got_offset;
2049 if (gsym != NULL)
2050 {
2051 gold_assert(gsym->has_got_offset(got_type));
2052 got_offset = gsym->got_offset(got_type) - target->got_size();
2053 }
2054 else
2055 {
2056 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2057 gold_assert(object->local_has_got_offset(r_sym, got_type));
2058 got_offset = (object->local_got_offset(r_sym, got_type)
2059 - target->got_size());
2060 }
2061 if (optimized_type == tls::TLSOPT_TO_IE)
2062 {
2063 gold_assert(tls_segment != NULL);
2064 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2065 got_offset, view, view_size);
2066 break;
2067 }
2068 else if (optimized_type == tls::TLSOPT_NONE)
2069 {
2070 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2071 {
2072 // Relocate the field with the offset of the pair of GOT
2073 // entries.
2074 Relocate_functions<32, false>::rel32(view, got_offset);
2075 }
2076 break;
2077 }
2078 }
2079 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2080 _("unsupported reloc %u"),
2081 r_type);
2082 break;
2083
2084 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2085 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
2086 {
2087 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2088 _("both SUN and GNU model "
2089 "TLS relocations"));
2090 break;
2091 }
2092 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2093 if (optimized_type == tls::TLSOPT_TO_LE)
2094 {
2095 gold_assert(tls_segment != NULL);
2096 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
2097 value, view, view_size);
2098 break;
2099 }
2100 else if (optimized_type == tls::TLSOPT_NONE)
2101 {
2102 // Relocate the field with the offset of the GOT entry for
2103 // the module index.
2104 unsigned int got_offset;
2105 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2106 - target->got_size());
2107 Relocate_functions<32, false>::rel32(view, got_offset);
2108 break;
2109 }
2110 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2111 _("unsupported reloc %u"),
2112 r_type);
2113 break;
2114
2115 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2116 if (optimized_type == tls::TLSOPT_TO_LE)
2117 {
2118 // This reloc can appear in debugging sections, in which
2119 // case we must not convert to local-exec. We decide what
2120 // to do based on whether the section is marked as
2121 // containing executable code. That is what the GNU linker
2122 // does as well.
2123 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2124 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2125 {
2126 gold_assert(tls_segment != NULL);
2127 value -= tls_segment->memsz();
2128 }
2129 }
2130 Relocate_functions<32, false>::rel32(view, value);
2131 break;
2132
2133 case elfcpp::R_386_TLS_IE: // Initial-exec
2134 case elfcpp::R_386_TLS_GOTIE:
2135 case elfcpp::R_386_TLS_IE_32:
2136 if (optimized_type == tls::TLSOPT_TO_LE)
2137 {
2138 gold_assert(tls_segment != NULL);
2139 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2140 rel, r_type, value, view,
2141 view_size);
2142 break;
2143 }
2144 else if (optimized_type == tls::TLSOPT_NONE)
2145 {
2146 // Relocate the field with the offset of the GOT entry for
2147 // the tp-relative offset of the symbol.
2148 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2149 ? GOT_TYPE_TLS_OFFSET
2150 : GOT_TYPE_TLS_NOFFSET);
2151 unsigned int got_offset;
2152 if (gsym != NULL)
2153 {
2154 gold_assert(gsym->has_got_offset(got_type));
2155 got_offset = gsym->got_offset(got_type);
2156 }
2157 else
2158 {
2159 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2160 gold_assert(object->local_has_got_offset(r_sym, got_type));
2161 got_offset = object->local_got_offset(r_sym, got_type);
2162 }
2163 // For the R_386_TLS_IE relocation, we need to apply the
2164 // absolute address of the GOT entry.
2165 if (r_type == elfcpp::R_386_TLS_IE)
2166 got_offset += target->got_plt_section()->address();
2167 // All GOT offsets are relative to the end of the GOT.
2168 got_offset -= target->got_size();
2169 Relocate_functions<32, false>::rel32(view, got_offset);
2170 break;
2171 }
2172 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2173 _("unsupported reloc %u"),
2174 r_type);
2175 break;
2176
2177 case elfcpp::R_386_TLS_LE: // Local-exec
2178 // If we're creating a shared library, a dynamic relocation will
2179 // have been created for this location, so do not apply it now.
2180 if (!parameters->options().shared())
2181 {
2182 gold_assert(tls_segment != NULL);
2183 value -= tls_segment->memsz();
2184 Relocate_functions<32, false>::rel32(view, value);
2185 }
2186 break;
2187
2188 case elfcpp::R_386_TLS_LE_32:
2189 // If we're creating a shared library, a dynamic relocation will
2190 // have been created for this location, so do not apply it now.
2191 if (!parameters->options().shared())
2192 {
2193 gold_assert(tls_segment != NULL);
2194 value = tls_segment->memsz() - value;
2195 Relocate_functions<32, false>::rel32(view, value);
2196 }
2197 break;
2198 }
2199 }
2200
2201 // Do a relocation in which we convert a TLS General-Dynamic to a
2202 // Local-Exec.
2203
2204 inline void
2205 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2206 size_t relnum,
2207 Output_segment* tls_segment,
2208 const elfcpp::Rel<32, false>& rel,
2209 unsigned int,
2210 elfcpp::Elf_types<32>::Elf_Addr value,
2211 unsigned char* view,
2212 section_size_type view_size)
2213 {
2214 // leal foo(,%reg,1),%eax; call ___tls_get_addr
2215 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2216 // leal foo(%reg),%eax; call ___tls_get_addr
2217 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2218
2219 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2220 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2221
2222 unsigned char op1 = view[-1];
2223 unsigned char op2 = view[-2];
2224
2225 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2226 op2 == 0x8d || op2 == 0x04);
2227 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2228
2229 int roff = 5;
2230
2231 if (op2 == 0x04)
2232 {
2233 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2234 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2235 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2236 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2237 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2238 }
2239 else
2240 {
2241 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2242 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2243 if (rel.get_r_offset() + 9 < view_size
2244 && view[9] == 0x90)
2245 {
2246 // There is a trailing nop. Use the size byte subl.
2247 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2248 roff = 6;
2249 }
2250 else
2251 {
2252 // Use the five byte subl.
2253 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2254 }
2255 }
2256
2257 value = tls_segment->memsz() - value;
2258 Relocate_functions<32, false>::rel32(view + roff, value);
2259
2260 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2261 // We can skip it.
2262 this->skip_call_tls_get_addr_ = true;
2263 }
2264
2265 // Do a relocation in which we convert a TLS General-Dynamic to an
2266 // Initial-Exec.
2267
2268 inline void
2269 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2270 size_t relnum,
2271 Output_segment*,
2272 const elfcpp::Rel<32, false>& rel,
2273 unsigned int,
2274 elfcpp::Elf_types<32>::Elf_Addr value,
2275 unsigned char* view,
2276 section_size_type view_size)
2277 {
2278 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2279 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2280
2281 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2282 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2283
2284 unsigned char op1 = view[-1];
2285 unsigned char op2 = view[-2];
2286
2287 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2288 op2 == 0x8d || op2 == 0x04);
2289 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2290
2291 int roff = 5;
2292
2293 // FIXME: For now, support only the first (SIB) form.
2294 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2295
2296 if (op2 == 0x04)
2297 {
2298 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2299 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2300 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2301 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2302 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2303 }
2304 else
2305 {
2306 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2307 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2308 if (rel.get_r_offset() + 9 < view_size
2309 && view[9] == 0x90)
2310 {
2311 // FIXME: This is not the right instruction sequence.
2312 // There is a trailing nop. Use the size byte subl.
2313 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2314 roff = 6;
2315 }
2316 else
2317 {
2318 // FIXME: This is not the right instruction sequence.
2319 // Use the five byte subl.
2320 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2321 }
2322 }
2323
2324 Relocate_functions<32, false>::rel32(view + roff, value);
2325
2326 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2327 // We can skip it.
2328 this->skip_call_tls_get_addr_ = true;
2329 }
2330
2331 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2332 // General-Dynamic to a Local-Exec.
2333
2334 inline void
2335 Target_i386::Relocate::tls_desc_gd_to_le(
2336 const Relocate_info<32, false>* relinfo,
2337 size_t relnum,
2338 Output_segment* tls_segment,
2339 const elfcpp::Rel<32, false>& rel,
2340 unsigned int r_type,
2341 elfcpp::Elf_types<32>::Elf_Addr value,
2342 unsigned char* view,
2343 section_size_type view_size)
2344 {
2345 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2346 {
2347 // leal foo@TLSDESC(%ebx), %eax
2348 // ==> leal foo@NTPOFF, %eax
2349 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2350 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2351 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2352 view[-2] == 0x8d && view[-1] == 0x83);
2353 view[-1] = 0x05;
2354 value -= tls_segment->memsz();
2355 Relocate_functions<32, false>::rel32(view, value);
2356 }
2357 else
2358 {
2359 // call *foo@TLSCALL(%eax)
2360 // ==> nop; nop
2361 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2362 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2363 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2364 view[0] == 0xff && view[1] == 0x10);
2365 view[0] = 0x66;
2366 view[1] = 0x90;
2367 }
2368 }
2369
2370 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2371 // General-Dynamic to an Initial-Exec.
2372
2373 inline void
2374 Target_i386::Relocate::tls_desc_gd_to_ie(
2375 const Relocate_info<32, false>* relinfo,
2376 size_t relnum,
2377 Output_segment*,
2378 const elfcpp::Rel<32, false>& rel,
2379 unsigned int r_type,
2380 elfcpp::Elf_types<32>::Elf_Addr value,
2381 unsigned char* view,
2382 section_size_type view_size)
2383 {
2384 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2385 {
2386 // leal foo@TLSDESC(%ebx), %eax
2387 // ==> movl foo@GOTNTPOFF(%ebx), %eax
2388 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2389 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2390 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2391 view[-2] == 0x8d && view[-1] == 0x83);
2392 view[-2] = 0x8b;
2393 Relocate_functions<32, false>::rel32(view, value);
2394 }
2395 else
2396 {
2397 // call *foo@TLSCALL(%eax)
2398 // ==> nop; nop
2399 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2400 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2401 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2402 view[0] == 0xff && view[1] == 0x10);
2403 view[0] = 0x66;
2404 view[1] = 0x90;
2405 }
2406 }
2407
2408 // Do a relocation in which we convert a TLS Local-Dynamic to a
2409 // Local-Exec.
2410
2411 inline void
2412 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2413 size_t relnum,
2414 Output_segment*,
2415 const elfcpp::Rel<32, false>& rel,
2416 unsigned int,
2417 elfcpp::Elf_types<32>::Elf_Addr,
2418 unsigned char* view,
2419 section_size_type view_size)
2420 {
2421 // leal foo(%reg), %eax; call ___tls_get_addr
2422 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2423
2424 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2425 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2426
2427 // FIXME: Does this test really always pass?
2428 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2429 view[-2] == 0x8d && view[-1] == 0x83);
2430
2431 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2432
2433 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2434
2435 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2436 // We can skip it.
2437 this->skip_call_tls_get_addr_ = true;
2438 }
2439
2440 // Do a relocation in which we convert a TLS Initial-Exec to a
2441 // Local-Exec.
2442
2443 inline void
2444 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2445 size_t relnum,
2446 Output_segment* tls_segment,
2447 const elfcpp::Rel<32, false>& rel,
2448 unsigned int r_type,
2449 elfcpp::Elf_types<32>::Elf_Addr value,
2450 unsigned char* view,
2451 section_size_type view_size)
2452 {
2453 // We have to actually change the instructions, which means that we
2454 // need to examine the opcodes to figure out which instruction we
2455 // are looking at.
2456 if (r_type == elfcpp::R_386_TLS_IE)
2457 {
2458 // movl %gs:XX,%eax ==> movl $YY,%eax
2459 // movl %gs:XX,%reg ==> movl $YY,%reg
2460 // addl %gs:XX,%reg ==> addl $YY,%reg
2461 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2462 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2463
2464 unsigned char op1 = view[-1];
2465 if (op1 == 0xa1)
2466 {
2467 // movl XX,%eax ==> movl $YY,%eax
2468 view[-1] = 0xb8;
2469 }
2470 else
2471 {
2472 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2473
2474 unsigned char op2 = view[-2];
2475 if (op2 == 0x8b)
2476 {
2477 // movl XX,%reg ==> movl $YY,%reg
2478 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2479 (op1 & 0xc7) == 0x05);
2480 view[-2] = 0xc7;
2481 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2482 }
2483 else if (op2 == 0x03)
2484 {
2485 // addl XX,%reg ==> addl $YY,%reg
2486 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2487 (op1 & 0xc7) == 0x05);
2488 view[-2] = 0x81;
2489 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2490 }
2491 else
2492 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2493 }
2494 }
2495 else
2496 {
2497 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2498 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2499 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2500 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2501 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2502
2503 unsigned char op1 = view[-1];
2504 unsigned char op2 = view[-2];
2505 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2506 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2507 if (op2 == 0x8b)
2508 {
2509 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2510 view[-2] = 0xc7;
2511 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2512 }
2513 else if (op2 == 0x2b)
2514 {
2515 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2516 view[-2] = 0x81;
2517 view[-1] = 0xe8 | ((op1 >> 3) & 7);
2518 }
2519 else if (op2 == 0x03)
2520 {
2521 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2522 view[-2] = 0x81;
2523 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2524 }
2525 else
2526 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2527 }
2528
2529 value = tls_segment->memsz() - value;
2530 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2531 value = - value;
2532
2533 Relocate_functions<32, false>::rel32(view, value);
2534 }
2535
2536 // Relocate section data.
2537
2538 void
2539 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2540 unsigned int sh_type,
2541 const unsigned char* prelocs,
2542 size_t reloc_count,
2543 Output_section* output_section,
2544 bool needs_special_offset_handling,
2545 unsigned char* view,
2546 elfcpp::Elf_types<32>::Elf_Addr address,
2547 section_size_type view_size,
2548 const Reloc_symbol_changes* reloc_symbol_changes)
2549 {
2550 gold_assert(sh_type == elfcpp::SHT_REL);
2551
2552 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2553 Target_i386::Relocate>(
2554 relinfo,
2555 this,
2556 prelocs,
2557 reloc_count,
2558 output_section,
2559 needs_special_offset_handling,
2560 view,
2561 address,
2562 view_size,
2563 reloc_symbol_changes);
2564 }
2565
2566 // Return the size of a relocation while scanning during a relocatable
2567 // link.
2568
2569 unsigned int
2570 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2571 unsigned int r_type,
2572 Relobj* object)
2573 {
2574 switch (r_type)
2575 {
2576 case elfcpp::R_386_NONE:
2577 case elfcpp::R_386_GNU_VTINHERIT:
2578 case elfcpp::R_386_GNU_VTENTRY:
2579 case elfcpp::R_386_TLS_GD: // Global-dynamic
2580 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2581 case elfcpp::R_386_TLS_DESC_CALL:
2582 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2583 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2584 case elfcpp::R_386_TLS_IE: // Initial-exec
2585 case elfcpp::R_386_TLS_IE_32:
2586 case elfcpp::R_386_TLS_GOTIE:
2587 case elfcpp::R_386_TLS_LE: // Local-exec
2588 case elfcpp::R_386_TLS_LE_32:
2589 return 0;
2590
2591 case elfcpp::R_386_32:
2592 case elfcpp::R_386_PC32:
2593 case elfcpp::R_386_GOT32:
2594 case elfcpp::R_386_PLT32:
2595 case elfcpp::R_386_GOTOFF:
2596 case elfcpp::R_386_GOTPC:
2597 return 4;
2598
2599 case elfcpp::R_386_16:
2600 case elfcpp::R_386_PC16:
2601 return 2;
2602
2603 case elfcpp::R_386_8:
2604 case elfcpp::R_386_PC8:
2605 return 1;
2606
2607 // These are relocations which should only be seen by the
2608 // dynamic linker, and should never be seen here.
2609 case elfcpp::R_386_COPY:
2610 case elfcpp::R_386_GLOB_DAT:
2611 case elfcpp::R_386_JUMP_SLOT:
2612 case elfcpp::R_386_RELATIVE:
2613 case elfcpp::R_386_TLS_TPOFF:
2614 case elfcpp::R_386_TLS_DTPMOD32:
2615 case elfcpp::R_386_TLS_DTPOFF32:
2616 case elfcpp::R_386_TLS_TPOFF32:
2617 case elfcpp::R_386_TLS_DESC:
2618 object->error(_("unexpected reloc %u in object file"), r_type);
2619 return 0;
2620
2621 case elfcpp::R_386_32PLT:
2622 case elfcpp::R_386_TLS_GD_32:
2623 case elfcpp::R_386_TLS_GD_PUSH:
2624 case elfcpp::R_386_TLS_GD_CALL:
2625 case elfcpp::R_386_TLS_GD_POP:
2626 case elfcpp::R_386_TLS_LDM_32:
2627 case elfcpp::R_386_TLS_LDM_PUSH:
2628 case elfcpp::R_386_TLS_LDM_CALL:
2629 case elfcpp::R_386_TLS_LDM_POP:
2630 case elfcpp::R_386_USED_BY_INTEL_200:
2631 default:
2632 object->error(_("unsupported reloc %u in object file"), r_type);
2633 return 0;
2634 }
2635 }
2636
2637 // Scan the relocs during a relocatable link.
2638
2639 void
2640 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
2641 Layout* layout,
2642 Sized_relobj<32, false>* object,
2643 unsigned int data_shndx,
2644 unsigned int sh_type,
2645 const unsigned char* prelocs,
2646 size_t reloc_count,
2647 Output_section* output_section,
2648 bool needs_special_offset_handling,
2649 size_t local_symbol_count,
2650 const unsigned char* plocal_symbols,
2651 Relocatable_relocs* rr)
2652 {
2653 gold_assert(sh_type == elfcpp::SHT_REL);
2654
2655 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2656 Relocatable_size_for_reloc> Scan_relocatable_relocs;
2657
2658 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2659 Scan_relocatable_relocs>(
2660 symtab,
2661 layout,
2662 object,
2663 data_shndx,
2664 prelocs,
2665 reloc_count,
2666 output_section,
2667 needs_special_offset_handling,
2668 local_symbol_count,
2669 plocal_symbols,
2670 rr);
2671 }
2672
2673 // Relocate a section during a relocatable link.
2674
2675 void
2676 Target_i386::relocate_for_relocatable(
2677 const Relocate_info<32, false>* relinfo,
2678 unsigned int sh_type,
2679 const unsigned char* prelocs,
2680 size_t reloc_count,
2681 Output_section* output_section,
2682 off_t offset_in_output_section,
2683 const Relocatable_relocs* rr,
2684 unsigned char* view,
2685 elfcpp::Elf_types<32>::Elf_Addr view_address,
2686 section_size_type view_size,
2687 unsigned char* reloc_view,
2688 section_size_type reloc_view_size)
2689 {
2690 gold_assert(sh_type == elfcpp::SHT_REL);
2691
2692 gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2693 relinfo,
2694 prelocs,
2695 reloc_count,
2696 output_section,
2697 offset_in_output_section,
2698 rr,
2699 view,
2700 view_address,
2701 view_size,
2702 reloc_view,
2703 reloc_view_size);
2704 }
2705
2706 // Return the value to use for a dynamic which requires special
2707 // treatment. This is how we support equality comparisons of function
2708 // pointers across shared library boundaries, as described in the
2709 // processor specific ABI supplement.
2710
2711 uint64_t
2712 Target_i386::do_dynsym_value(const Symbol* gsym) const
2713 {
2714 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2715 return this->plt_section()->address() + gsym->plt_offset();
2716 }
2717
2718 // Return a string used to fill a code section with nops to take up
2719 // the specified length.
2720
2721 std::string
2722 Target_i386::do_code_fill(section_size_type length) const
2723 {
2724 if (length >= 16)
2725 {
2726 // Build a jmp instruction to skip over the bytes.
2727 unsigned char jmp[5];
2728 jmp[0] = 0xe9;
2729 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2730 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2731 + std::string(length - 5, '\0'));
2732 }
2733
2734 // Nop sequences of various lengths.
2735 const char nop1[1] = { 0x90 }; // nop
2736 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2737 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
2738 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
2739 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
2740 0x00 }; // leal 0(%esi,1),%esi
2741 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2742 0x00, 0x00 };
2743 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2744 0x00, 0x00, 0x00 };
2745 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
2746 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2747 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
2748 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
2749 0x00 };
2750 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2751 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2752 0x00, 0x00 };
2753 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2754 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2755 0x00, 0x00, 0x00 };
2756 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2757 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2758 0x00, 0x00, 0x00, 0x00 };
2759 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2760 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2761 0x27, 0x00, 0x00, 0x00,
2762 0x00 };
2763 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2764 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2765 0xbc, 0x27, 0x00, 0x00,
2766 0x00, 0x00 };
2767 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2768 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2769 0x90, 0x90, 0x90, 0x90,
2770 0x90, 0x90, 0x90 };
2771
2772 const char* nops[16] = {
2773 NULL,
2774 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2775 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2776 };
2777
2778 return std::string(nops[length], length);
2779 }
2780
2781 // Return whether SYM should be treated as a call to a non-split
2782 // function. We don't want that to be true of a call to a
2783 // get_pc_thunk function.
2784
2785 bool
2786 Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
2787 {
2788 return (sym->type() == elfcpp::STT_FUNC
2789 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
2790 }
2791
2792 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2793 // compiled with -fstack-split. The function calls non-stack-split
2794 // code. We have to change the function so that it always ensures
2795 // that it has enough stack space to run some random function.
2796
2797 void
2798 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2799 section_offset_type fnoffset,
2800 section_size_type fnsize,
2801 unsigned char* view,
2802 section_size_type view_size,
2803 std::string* from,
2804 std::string* to) const
2805 {
2806 // The function starts with a comparison of the stack pointer and a
2807 // field in the TCB. This is followed by a jump.
2808
2809 // cmp %gs:NN,%esp
2810 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2811 && fnsize > 7)
2812 {
2813 // We will call __morestack if the carry flag is set after this
2814 // comparison. We turn the comparison into an stc instruction
2815 // and some nops.
2816 view[fnoffset] = '\xf9';
2817 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2818 }
2819 // lea NN(%esp),%ecx
2820 // lea NN(%esp),%edx
2821 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2822 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
2823 && fnsize > 7)
2824 {
2825 // This is loading an offset from the stack pointer for a
2826 // comparison. The offset is negative, so we decrease the
2827 // offset by the amount of space we need for the stack. This
2828 // means we will avoid calling __morestack if there happens to
2829 // be plenty of space on the stack already.
2830 unsigned char* pval = view + fnoffset + 3;
2831 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2832 val -= parameters->options().split_stack_adjust_size();
2833 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2834 }
2835 else
2836 {
2837 if (!object->has_no_split_stack())
2838 object->error(_("failed to match split-stack sequence at "
2839 "section %u offset %0zx"),
2840 shndx, static_cast<size_t>(fnoffset));
2841 return;
2842 }
2843
2844 // We have to change the function so that it calls
2845 // __morestack_non_split instead of __morestack. The former will
2846 // allocate additional stack space.
2847 *from = "__morestack";
2848 *to = "__morestack_non_split";
2849 }
2850
2851 // The selector for i386 object files.
2852
2853 class Target_selector_i386 : public Target_selector_freebsd
2854 {
2855 public:
2856 Target_selector_i386()
2857 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2858 "elf32-i386", "elf32-i386-freebsd")
2859 { }
2860
2861 Target*
2862 do_instantiate_target()
2863 { return new Target_i386(); }
2864 };
2865
2866 Target_selector_i386 target_selector_i386;
2867
2868 } // End anonymous namespace.
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