* object.h (class Relocate_info): Add reloc_shdr and data_shdr
[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), rel_dyn_(NULL),
63 copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
64 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
65 { }
66
67 // Process the relocations to determine unreferenced sections for
68 // garbage collection.
69 void
70 gc_process_relocs(const General_options& options,
71 Symbol_table* symtab,
72 Layout* layout,
73 Sized_relobj<32, false>* object,
74 unsigned int data_shndx,
75 unsigned int sh_type,
76 const unsigned char* prelocs,
77 size_t reloc_count,
78 Output_section* output_section,
79 bool needs_special_offset_handling,
80 size_t local_symbol_count,
81 const unsigned char* plocal_symbols);
82
83 // Scan the relocations to look for symbol adjustments.
84 void
85 scan_relocs(const General_options& options,
86 Symbol_table* symtab,
87 Layout* layout,
88 Sized_relobj<32, false>* object,
89 unsigned int data_shndx,
90 unsigned int sh_type,
91 const unsigned char* prelocs,
92 size_t reloc_count,
93 Output_section* output_section,
94 bool needs_special_offset_handling,
95 size_t local_symbol_count,
96 const unsigned char* plocal_symbols);
97
98 // Finalize the sections.
99 void
100 do_finalize_sections(Layout*);
101
102 // Return the value to use for a dynamic which requires special
103 // treatment.
104 uint64_t
105 do_dynsym_value(const Symbol*) const;
106
107 // Relocate a section.
108 void
109 relocate_section(const Relocate_info<32, false>*,
110 unsigned int sh_type,
111 const unsigned char* prelocs,
112 size_t reloc_count,
113 Output_section* output_section,
114 bool needs_special_offset_handling,
115 unsigned char* view,
116 elfcpp::Elf_types<32>::Elf_Addr view_address,
117 section_size_type view_size,
118 const Reloc_symbol_changes*);
119
120 // Scan the relocs during a relocatable link.
121 void
122 scan_relocatable_relocs(const General_options& options,
123 Symbol_table* symtab,
124 Layout* layout,
125 Sized_relobj<32, false>* object,
126 unsigned int data_shndx,
127 unsigned int sh_type,
128 const unsigned char* prelocs,
129 size_t reloc_count,
130 Output_section* output_section,
131 bool needs_special_offset_handling,
132 size_t local_symbol_count,
133 const unsigned char* plocal_symbols,
134 Relocatable_relocs*);
135
136 // Relocate a section during a relocatable link.
137 void
138 relocate_for_relocatable(const Relocate_info<32, false>*,
139 unsigned int sh_type,
140 const unsigned char* prelocs,
141 size_t reloc_count,
142 Output_section* output_section,
143 off_t offset_in_output_section,
144 const Relocatable_relocs*,
145 unsigned char* view,
146 elfcpp::Elf_types<32>::Elf_Addr view_address,
147 section_size_type view_size,
148 unsigned char* reloc_view,
149 section_size_type reloc_view_size);
150
151 // Return a string used to fill a code section with nops.
152 std::string
153 do_code_fill(section_size_type length) const;
154
155 // Return whether SYM is defined by the ABI.
156 bool
157 do_is_defined_by_abi(const Symbol* sym) const
158 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
159
160 // Return whether a symbol name implies a local label. The UnixWare
161 // 2.1 cc generates temporary symbols that start with .X, so we
162 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
163 // If so, we should move the .X recognition into
164 // Target::do_is_local_label_name.
165 bool
166 do_is_local_label_name(const char* name) const
167 {
168 if (name[0] == '.' && name[1] == 'X')
169 return true;
170 return Target::do_is_local_label_name(name);
171 }
172
173 // Adjust -fstack-split code which calls non-stack-split code.
174 void
175 do_calls_non_split(Relobj* object, unsigned int shndx,
176 section_offset_type fnoffset, section_size_type fnsize,
177 unsigned char* view, section_size_type view_size,
178 std::string* from, std::string* to) const;
179
180 // Return the size of the GOT section.
181 section_size_type
182 got_size()
183 {
184 gold_assert(this->got_ != NULL);
185 return this->got_->data_size();
186 }
187
188 private:
189 // The class which scans relocations.
190 struct Scan
191 {
192 inline void
193 local(const General_options& options, Symbol_table* symtab,
194 Layout* layout, Target_i386* target,
195 Sized_relobj<32, false>* object,
196 unsigned int data_shndx,
197 Output_section* output_section,
198 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
199 const elfcpp::Sym<32, false>& lsym);
200
201 inline void
202 global(const General_options& options, Symbol_table* symtab,
203 Layout* layout, Target_i386* target,
204 Sized_relobj<32, false>* object,
205 unsigned int data_shndx,
206 Output_section* output_section,
207 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
208 Symbol* gsym);
209
210 static void
211 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
212
213 static void
214 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
215 Symbol*);
216 };
217
218 // The class which implements relocation.
219 class Relocate
220 {
221 public:
222 Relocate()
223 : skip_call_tls_get_addr_(false),
224 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
225 { }
226
227 ~Relocate()
228 {
229 if (this->skip_call_tls_get_addr_)
230 {
231 // FIXME: This needs to specify the location somehow.
232 gold_error(_("missing expected TLS relocation"));
233 }
234 }
235
236 // Return whether the static relocation needs to be applied.
237 inline bool
238 should_apply_static_reloc(const Sized_symbol<32>* gsym,
239 int ref_flags,
240 bool is_32bit,
241 Output_section* output_section);
242
243 // Do a relocation. Return false if the caller should not issue
244 // any warnings about this relocation.
245 inline bool
246 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
247 size_t relnum, const elfcpp::Rel<32, false>&,
248 unsigned int r_type, const Sized_symbol<32>*,
249 const Symbol_value<32>*,
250 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
251 section_size_type);
252
253 private:
254 // Do a TLS relocation.
255 inline void
256 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
257 size_t relnum, const elfcpp::Rel<32, false>&,
258 unsigned int r_type, const Sized_symbol<32>*,
259 const Symbol_value<32>*,
260 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
261 section_size_type);
262
263 // Do a TLS General-Dynamic to Initial-Exec transition.
264 inline void
265 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
266 Output_segment* tls_segment,
267 const elfcpp::Rel<32, false>&, unsigned int r_type,
268 elfcpp::Elf_types<32>::Elf_Addr value,
269 unsigned char* view,
270 section_size_type view_size);
271
272 // Do a TLS General-Dynamic to Local-Exec transition.
273 inline void
274 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
275 Output_segment* tls_segment,
276 const elfcpp::Rel<32, false>&, unsigned int r_type,
277 elfcpp::Elf_types<32>::Elf_Addr value,
278 unsigned char* view,
279 section_size_type view_size);
280
281 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
282 // transition.
283 inline void
284 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
285 Output_segment* tls_segment,
286 const elfcpp::Rel<32, false>&, unsigned int r_type,
287 elfcpp::Elf_types<32>::Elf_Addr value,
288 unsigned char* view,
289 section_size_type view_size);
290
291 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
292 // transition.
293 inline void
294 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
295 Output_segment* tls_segment,
296 const elfcpp::Rel<32, false>&, unsigned int r_type,
297 elfcpp::Elf_types<32>::Elf_Addr value,
298 unsigned char* view,
299 section_size_type view_size);
300
301 // Do a TLS Local-Dynamic to Local-Exec transition.
302 inline void
303 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
304 Output_segment* tls_segment,
305 const elfcpp::Rel<32, false>&, unsigned int r_type,
306 elfcpp::Elf_types<32>::Elf_Addr value,
307 unsigned char* view,
308 section_size_type view_size);
309
310 // Do a TLS Initial-Exec to Local-Exec transition.
311 static inline void
312 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
313 Output_segment* tls_segment,
314 const elfcpp::Rel<32, false>&, unsigned int r_type,
315 elfcpp::Elf_types<32>::Elf_Addr value,
316 unsigned char* view,
317 section_size_type view_size);
318
319 // We need to keep track of which type of local dynamic relocation
320 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
321 enum Local_dynamic_type
322 {
323 LOCAL_DYNAMIC_NONE,
324 LOCAL_DYNAMIC_SUN,
325 LOCAL_DYNAMIC_GNU
326 };
327
328 // This is set if we should skip the next reloc, which should be a
329 // PLT32 reloc against ___tls_get_addr.
330 bool skip_call_tls_get_addr_;
331 // The type of local dynamic relocation we have seen in the section
332 // being relocated, if any.
333 Local_dynamic_type local_dynamic_type_;
334 };
335
336 // A class which returns the size required for a relocation type,
337 // used while scanning relocs during a relocatable link.
338 class Relocatable_size_for_reloc
339 {
340 public:
341 unsigned int
342 get_size_for_reloc(unsigned int, Relobj*);
343 };
344
345 // Adjust TLS relocation type based on the options and whether this
346 // is a local symbol.
347 static tls::Tls_optimization
348 optimize_tls_reloc(bool is_final, int r_type);
349
350 // Get the GOT section, creating it if necessary.
351 Output_data_got<32, false>*
352 got_section(Symbol_table*, Layout*);
353
354 // Get the GOT PLT section.
355 Output_data_space*
356 got_plt_section() const
357 {
358 gold_assert(this->got_plt_ != NULL);
359 return this->got_plt_;
360 }
361
362 // Create a PLT entry for a global symbol.
363 void
364 make_plt_entry(Symbol_table*, Layout*, Symbol*);
365
366 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
367 void
368 define_tls_base_symbol(Symbol_table*, Layout*);
369
370 // Create a GOT entry for the TLS module index.
371 unsigned int
372 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
373 Sized_relobj<32, false>* object);
374
375 // Get the PLT section.
376 const Output_data_plt_i386*
377 plt_section() const
378 {
379 gold_assert(this->plt_ != NULL);
380 return this->plt_;
381 }
382
383 // Get the dynamic reloc section, creating it if necessary.
384 Reloc_section*
385 rel_dyn_section(Layout*);
386
387 // Add a potential copy relocation.
388 void
389 copy_reloc(Symbol_table* symtab, Layout* layout,
390 Sized_relobj<32, false>* object,
391 unsigned int shndx, Output_section* output_section,
392 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
393 {
394 this->copy_relocs_.copy_reloc(symtab, layout,
395 symtab->get_sized_symbol<32>(sym),
396 object, shndx, output_section, reloc,
397 this->rel_dyn_section(layout));
398 }
399
400 // Information about this specific target which we pass to the
401 // general Target structure.
402 static const Target::Target_info i386_info;
403
404 // The types of GOT entries needed for this platform.
405 enum Got_type
406 {
407 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
408 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
409 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
410 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
411 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
412 };
413
414 // The GOT section.
415 Output_data_got<32, false>* got_;
416 // The PLT section.
417 Output_data_plt_i386* plt_;
418 // The GOT PLT section.
419 Output_data_space* got_plt_;
420 // The dynamic reloc section.
421 Reloc_section* rel_dyn_;
422 // Relocs saved to avoid a COPY reloc.
423 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
424 // Space for variables copied with a COPY reloc.
425 Output_data_space* dynbss_;
426 // Offset of the GOT entry for the TLS module index.
427 unsigned int got_mod_index_offset_;
428 // True if the _TLS_MODULE_BASE_ symbol has been defined.
429 bool tls_base_symbol_defined_;
430 };
431
432 const Target::Target_info Target_i386::i386_info =
433 {
434 32, // size
435 false, // is_big_endian
436 elfcpp::EM_386, // machine_code
437 false, // has_make_symbol
438 false, // has_resolve
439 true, // has_code_fill
440 true, // is_default_stack_executable
441 '\0', // wrap_char
442 "/usr/lib/libc.so.1", // dynamic_linker
443 0x08048000, // default_text_segment_address
444 0x1000, // abi_pagesize (overridable by -z max-page-size)
445 0x1000, // common_pagesize (overridable by -z common-page-size)
446 elfcpp::SHN_UNDEF, // small_common_shndx
447 elfcpp::SHN_UNDEF, // large_common_shndx
448 0, // small_common_section_flags
449 0 // large_common_section_flags
450 };
451
452 // Get the GOT section, creating it if necessary.
453
454 Output_data_got<32, false>*
455 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
456 {
457 if (this->got_ == NULL)
458 {
459 gold_assert(symtab != NULL && layout != NULL);
460
461 this->got_ = new Output_data_got<32, false>();
462
463 Output_section* os;
464 os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
465 (elfcpp::SHF_ALLOC
466 | elfcpp::SHF_WRITE),
467 this->got_);
468 os->set_is_relro();
469
470 // The old GNU linker creates a .got.plt section. We just
471 // create another set of data in the .got section. Note that we
472 // always create a PLT if we create a GOT, although the PLT
473 // might be empty.
474 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
475 os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
476 (elfcpp::SHF_ALLOC
477 | elfcpp::SHF_WRITE),
478 this->got_plt_);
479 os->set_is_relro();
480
481 // The first three entries are reserved.
482 this->got_plt_->set_current_data_size(3 * 4);
483
484 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
485 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
486 this->got_plt_,
487 0, 0, elfcpp::STT_OBJECT,
488 elfcpp::STB_LOCAL,
489 elfcpp::STV_HIDDEN, 0,
490 false, false);
491 }
492
493 return this->got_;
494 }
495
496 // Get the dynamic reloc section, creating it if necessary.
497
498 Target_i386::Reloc_section*
499 Target_i386::rel_dyn_section(Layout* layout)
500 {
501 if (this->rel_dyn_ == NULL)
502 {
503 gold_assert(layout != NULL);
504 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
505 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
506 elfcpp::SHF_ALLOC, this->rel_dyn_);
507 }
508 return this->rel_dyn_;
509 }
510
511 // A class to handle the PLT data.
512
513 class Output_data_plt_i386 : public Output_section_data
514 {
515 public:
516 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
517
518 Output_data_plt_i386(Layout*, Output_data_space*);
519
520 // Add an entry to the PLT.
521 void
522 add_entry(Symbol* gsym);
523
524 // Return the .rel.plt section data.
525 const Reloc_section*
526 rel_plt() const
527 { return this->rel_; }
528
529 protected:
530 void
531 do_adjust_output_section(Output_section* os);
532
533 // Write to a map file.
534 void
535 do_print_to_mapfile(Mapfile* mapfile) const
536 { mapfile->print_output_data(this, _("** PLT")); }
537
538 private:
539 // The size of an entry in the PLT.
540 static const int plt_entry_size = 16;
541
542 // The first entry in the PLT for an executable.
543 static unsigned char exec_first_plt_entry[plt_entry_size];
544
545 // The first entry in the PLT for a shared object.
546 static unsigned char dyn_first_plt_entry[plt_entry_size];
547
548 // Other entries in the PLT for an executable.
549 static unsigned char exec_plt_entry[plt_entry_size];
550
551 // Other entries in the PLT for a shared object.
552 static unsigned char dyn_plt_entry[plt_entry_size];
553
554 // Set the final size.
555 void
556 set_final_data_size()
557 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
558
559 // Write out the PLT data.
560 void
561 do_write(Output_file*);
562
563 // The reloc section.
564 Reloc_section* rel_;
565 // The .got.plt section.
566 Output_data_space* got_plt_;
567 // The number of PLT entries.
568 unsigned int count_;
569 };
570
571 // Create the PLT section. The ordinary .got section is an argument,
572 // since we need to refer to the start. We also create our own .got
573 // section just for PLT entries.
574
575 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
576 Output_data_space* got_plt)
577 : Output_section_data(4), got_plt_(got_plt), count_(0)
578 {
579 this->rel_ = new Reloc_section(false);
580 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
581 elfcpp::SHF_ALLOC, this->rel_);
582 }
583
584 void
585 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
586 {
587 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
588 // linker, and so do we.
589 os->set_entsize(4);
590 }
591
592 // Add an entry to the PLT.
593
594 void
595 Output_data_plt_i386::add_entry(Symbol* gsym)
596 {
597 gold_assert(!gsym->has_plt_offset());
598
599 // Note that when setting the PLT offset we skip the initial
600 // reserved PLT entry.
601 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
602
603 ++this->count_;
604
605 section_offset_type got_offset = this->got_plt_->current_data_size();
606
607 // Every PLT entry needs a GOT entry which points back to the PLT
608 // entry (this will be changed by the dynamic linker, normally
609 // lazily when the function is called).
610 this->got_plt_->set_current_data_size(got_offset + 4);
611
612 // Every PLT entry needs a reloc.
613 gsym->set_needs_dynsym_entry();
614 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
615 got_offset);
616
617 // Note that we don't need to save the symbol. The contents of the
618 // PLT are independent of which symbols are used. The symbols only
619 // appear in the relocations.
620 }
621
622 // The first entry in the PLT for an executable.
623
624 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
625 {
626 0xff, 0x35, // pushl contents of memory address
627 0, 0, 0, 0, // replaced with address of .got + 4
628 0xff, 0x25, // jmp indirect
629 0, 0, 0, 0, // replaced with address of .got + 8
630 0, 0, 0, 0 // unused
631 };
632
633 // The first entry in the PLT for a shared object.
634
635 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
636 {
637 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
638 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
639 0, 0, 0, 0 // unused
640 };
641
642 // Subsequent entries in the PLT for an executable.
643
644 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
645 {
646 0xff, 0x25, // jmp indirect
647 0, 0, 0, 0, // replaced with address of symbol in .got
648 0x68, // pushl immediate
649 0, 0, 0, 0, // replaced with offset into relocation table
650 0xe9, // jmp relative
651 0, 0, 0, 0 // replaced with offset to start of .plt
652 };
653
654 // Subsequent entries in the PLT for a shared object.
655
656 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
657 {
658 0xff, 0xa3, // jmp *offset(%ebx)
659 0, 0, 0, 0, // replaced with offset of symbol in .got
660 0x68, // pushl immediate
661 0, 0, 0, 0, // replaced with offset into relocation table
662 0xe9, // jmp relative
663 0, 0, 0, 0 // replaced with offset to start of .plt
664 };
665
666 // Write out the PLT. This uses the hand-coded instructions above,
667 // and adjusts them as needed. This is all specified by the i386 ELF
668 // Processor Supplement.
669
670 void
671 Output_data_plt_i386::do_write(Output_file* of)
672 {
673 const off_t offset = this->offset();
674 const section_size_type oview_size =
675 convert_to_section_size_type(this->data_size());
676 unsigned char* const oview = of->get_output_view(offset, oview_size);
677
678 const off_t got_file_offset = this->got_plt_->offset();
679 const section_size_type got_size =
680 convert_to_section_size_type(this->got_plt_->data_size());
681 unsigned char* const got_view = of->get_output_view(got_file_offset,
682 got_size);
683
684 unsigned char* pov = oview;
685
686 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
687 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
688
689 if (parameters->options().output_is_position_independent())
690 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
691 else
692 {
693 memcpy(pov, exec_first_plt_entry, plt_entry_size);
694 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
695 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
696 }
697 pov += plt_entry_size;
698
699 unsigned char* got_pov = got_view;
700
701 memset(got_pov, 0, 12);
702 got_pov += 12;
703
704 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
705
706 unsigned int plt_offset = plt_entry_size;
707 unsigned int plt_rel_offset = 0;
708 unsigned int got_offset = 12;
709 const unsigned int count = this->count_;
710 for (unsigned int i = 0;
711 i < count;
712 ++i,
713 pov += plt_entry_size,
714 got_pov += 4,
715 plt_offset += plt_entry_size,
716 plt_rel_offset += rel_size,
717 got_offset += 4)
718 {
719 // Set and adjust the PLT entry itself.
720
721 if (parameters->options().output_is_position_independent())
722 {
723 memcpy(pov, dyn_plt_entry, plt_entry_size);
724 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
725 }
726 else
727 {
728 memcpy(pov, exec_plt_entry, plt_entry_size);
729 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
730 (got_address
731 + got_offset));
732 }
733
734 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
735 elfcpp::Swap<32, false>::writeval(pov + 12,
736 - (plt_offset + plt_entry_size));
737
738 // Set the entry in the GOT.
739 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
740 }
741
742 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
743 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
744
745 of->write_output_view(offset, oview_size, oview);
746 of->write_output_view(got_file_offset, got_size, got_view);
747 }
748
749 // Create a PLT entry for a global symbol.
750
751 void
752 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
753 {
754 if (gsym->has_plt_offset())
755 return;
756
757 if (this->plt_ == NULL)
758 {
759 // Create the GOT sections first.
760 this->got_section(symtab, layout);
761
762 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
763 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
764 (elfcpp::SHF_ALLOC
765 | elfcpp::SHF_EXECINSTR),
766 this->plt_);
767 }
768
769 this->plt_->add_entry(gsym);
770 }
771
772 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
773
774 void
775 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
776 {
777 if (this->tls_base_symbol_defined_)
778 return;
779
780 Output_segment* tls_segment = layout->tls_segment();
781 if (tls_segment != NULL)
782 {
783 bool is_exec = parameters->options().output_is_executable();
784 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
785 tls_segment, 0, 0,
786 elfcpp::STT_TLS,
787 elfcpp::STB_LOCAL,
788 elfcpp::STV_HIDDEN, 0,
789 (is_exec
790 ? Symbol::SEGMENT_END
791 : Symbol::SEGMENT_START),
792 true);
793 }
794 this->tls_base_symbol_defined_ = true;
795 }
796
797 // Create a GOT entry for the TLS module index.
798
799 unsigned int
800 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
801 Sized_relobj<32, false>* object)
802 {
803 if (this->got_mod_index_offset_ == -1U)
804 {
805 gold_assert(symtab != NULL && layout != NULL && object != NULL);
806 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
807 Output_data_got<32, false>* got = this->got_section(symtab, layout);
808 unsigned int got_offset = got->add_constant(0);
809 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
810 got_offset);
811 got->add_constant(0);
812 this->got_mod_index_offset_ = got_offset;
813 }
814 return this->got_mod_index_offset_;
815 }
816
817 // Optimize the TLS relocation type based on what we know about the
818 // symbol. IS_FINAL is true if the final address of this symbol is
819 // known at link time.
820
821 tls::Tls_optimization
822 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
823 {
824 // If we are generating a shared library, then we can't do anything
825 // in the linker.
826 if (parameters->options().shared())
827 return tls::TLSOPT_NONE;
828
829 switch (r_type)
830 {
831 case elfcpp::R_386_TLS_GD:
832 case elfcpp::R_386_TLS_GOTDESC:
833 case elfcpp::R_386_TLS_DESC_CALL:
834 // These are General-Dynamic which permits fully general TLS
835 // access. Since we know that we are generating an executable,
836 // we can convert this to Initial-Exec. If we also know that
837 // this is a local symbol, we can further switch to Local-Exec.
838 if (is_final)
839 return tls::TLSOPT_TO_LE;
840 return tls::TLSOPT_TO_IE;
841
842 case elfcpp::R_386_TLS_LDM:
843 // This is Local-Dynamic, which refers to a local symbol in the
844 // dynamic TLS block. Since we know that we generating an
845 // executable, we can switch to Local-Exec.
846 return tls::TLSOPT_TO_LE;
847
848 case elfcpp::R_386_TLS_LDO_32:
849 // Another type of Local-Dynamic relocation.
850 return tls::TLSOPT_TO_LE;
851
852 case elfcpp::R_386_TLS_IE:
853 case elfcpp::R_386_TLS_GOTIE:
854 case elfcpp::R_386_TLS_IE_32:
855 // These are Initial-Exec relocs which get the thread offset
856 // from the GOT. If we know that we are linking against the
857 // local symbol, we can switch to Local-Exec, which links the
858 // thread offset into the instruction.
859 if (is_final)
860 return tls::TLSOPT_TO_LE;
861 return tls::TLSOPT_NONE;
862
863 case elfcpp::R_386_TLS_LE:
864 case elfcpp::R_386_TLS_LE_32:
865 // When we already have Local-Exec, there is nothing further we
866 // can do.
867 return tls::TLSOPT_NONE;
868
869 default:
870 gold_unreachable();
871 }
872 }
873
874 // Report an unsupported relocation against a local symbol.
875
876 void
877 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
878 unsigned int r_type)
879 {
880 gold_error(_("%s: unsupported reloc %u against local symbol"),
881 object->name().c_str(), r_type);
882 }
883
884 // Scan a relocation for a local symbol.
885
886 inline void
887 Target_i386::Scan::local(const General_options&,
888 Symbol_table* symtab,
889 Layout* layout,
890 Target_i386* target,
891 Sized_relobj<32, false>* object,
892 unsigned int data_shndx,
893 Output_section* output_section,
894 const elfcpp::Rel<32, false>& reloc,
895 unsigned int r_type,
896 const elfcpp::Sym<32, false>& lsym)
897 {
898 switch (r_type)
899 {
900 case elfcpp::R_386_NONE:
901 case elfcpp::R_386_GNU_VTINHERIT:
902 case elfcpp::R_386_GNU_VTENTRY:
903 break;
904
905 case elfcpp::R_386_32:
906 // If building a shared library (or a position-independent
907 // executable), we need to create a dynamic relocation for
908 // this location. The relocation applied at link time will
909 // apply the link-time value, so we flag the location with
910 // an R_386_RELATIVE relocation so the dynamic loader can
911 // relocate it easily.
912 if (parameters->options().output_is_position_independent())
913 {
914 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
915 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
916 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
917 output_section, data_shndx,
918 reloc.get_r_offset());
919 }
920 break;
921
922 case elfcpp::R_386_16:
923 case elfcpp::R_386_8:
924 // If building a shared library (or a position-independent
925 // executable), we need to create a dynamic relocation for
926 // this location. Because the addend needs to remain in the
927 // data section, we need to be careful not to apply this
928 // relocation statically.
929 if (parameters->options().output_is_position_independent())
930 {
931 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
932 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
933 if (lsym.get_st_type() != elfcpp::STT_SECTION)
934 rel_dyn->add_local(object, r_sym, r_type, output_section,
935 data_shndx, reloc.get_r_offset());
936 else
937 {
938 gold_assert(lsym.get_st_value() == 0);
939 unsigned int shndx = lsym.get_st_shndx();
940 bool is_ordinary;
941 shndx = object->adjust_sym_shndx(r_sym, shndx,
942 &is_ordinary);
943 if (!is_ordinary)
944 object->error(_("section symbol %u has bad shndx %u"),
945 r_sym, shndx);
946 else
947 rel_dyn->add_local_section(object, shndx,
948 r_type, output_section,
949 data_shndx, reloc.get_r_offset());
950 }
951 }
952 break;
953
954 case elfcpp::R_386_PC32:
955 case elfcpp::R_386_PC16:
956 case elfcpp::R_386_PC8:
957 break;
958
959 case elfcpp::R_386_PLT32:
960 // Since we know this is a local symbol, we can handle this as a
961 // PC32 reloc.
962 break;
963
964 case elfcpp::R_386_GOTOFF:
965 case elfcpp::R_386_GOTPC:
966 // We need a GOT section.
967 target->got_section(symtab, layout);
968 break;
969
970 case elfcpp::R_386_GOT32:
971 {
972 // The symbol requires a GOT entry.
973 Output_data_got<32, false>* got = target->got_section(symtab, layout);
974 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
975 if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
976 {
977 // If we are generating a shared object, we need to add a
978 // dynamic RELATIVE relocation for this symbol's GOT entry.
979 if (parameters->options().output_is_position_independent())
980 {
981 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
982 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
983 rel_dyn->add_local_relative(
984 object, r_sym, elfcpp::R_386_RELATIVE, got,
985 object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
986 }
987 }
988 }
989 break;
990
991 // These are relocations which should only be seen by the
992 // dynamic linker, and should never be seen here.
993 case elfcpp::R_386_COPY:
994 case elfcpp::R_386_GLOB_DAT:
995 case elfcpp::R_386_JUMP_SLOT:
996 case elfcpp::R_386_RELATIVE:
997 case elfcpp::R_386_TLS_TPOFF:
998 case elfcpp::R_386_TLS_DTPMOD32:
999 case elfcpp::R_386_TLS_DTPOFF32:
1000 case elfcpp::R_386_TLS_TPOFF32:
1001 case elfcpp::R_386_TLS_DESC:
1002 gold_error(_("%s: unexpected reloc %u in object file"),
1003 object->name().c_str(), r_type);
1004 break;
1005
1006 // These are initial TLS relocs, which are expected when
1007 // linking.
1008 case elfcpp::R_386_TLS_GD: // Global-dynamic
1009 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1010 case elfcpp::R_386_TLS_DESC_CALL:
1011 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1012 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1013 case elfcpp::R_386_TLS_IE: // Initial-exec
1014 case elfcpp::R_386_TLS_IE_32:
1015 case elfcpp::R_386_TLS_GOTIE:
1016 case elfcpp::R_386_TLS_LE: // Local-exec
1017 case elfcpp::R_386_TLS_LE_32:
1018 {
1019 bool output_is_shared = parameters->options().shared();
1020 const tls::Tls_optimization optimized_type
1021 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1022 switch (r_type)
1023 {
1024 case elfcpp::R_386_TLS_GD: // Global-dynamic
1025 if (optimized_type == tls::TLSOPT_NONE)
1026 {
1027 // Create a pair of GOT entries for the module index and
1028 // dtv-relative offset.
1029 Output_data_got<32, false>* got
1030 = target->got_section(symtab, layout);
1031 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1032 unsigned int shndx = lsym.get_st_shndx();
1033 bool is_ordinary;
1034 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1035 if (!is_ordinary)
1036 object->error(_("local symbol %u has bad shndx %u"),
1037 r_sym, shndx);
1038 else
1039 got->add_local_pair_with_rel(object, r_sym, shndx,
1040 GOT_TYPE_TLS_PAIR,
1041 target->rel_dyn_section(layout),
1042 elfcpp::R_386_TLS_DTPMOD32, 0);
1043 }
1044 else if (optimized_type != tls::TLSOPT_TO_LE)
1045 unsupported_reloc_local(object, r_type);
1046 break;
1047
1048 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1049 target->define_tls_base_symbol(symtab, layout);
1050 if (optimized_type == tls::TLSOPT_NONE)
1051 {
1052 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1053 Output_data_got<32, false>* got
1054 = target->got_section(symtab, layout);
1055 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1056 unsigned int shndx = lsym.get_st_shndx();
1057 bool is_ordinary;
1058 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1059 if (!is_ordinary)
1060 object->error(_("local symbol %u has bad shndx %u"),
1061 r_sym, shndx);
1062 else
1063 got->add_local_pair_with_rel(object, r_sym, shndx,
1064 GOT_TYPE_TLS_DESC,
1065 target->rel_dyn_section(layout),
1066 elfcpp::R_386_TLS_DESC, 0);
1067 }
1068 else if (optimized_type != tls::TLSOPT_TO_LE)
1069 unsupported_reloc_local(object, r_type);
1070 break;
1071
1072 case elfcpp::R_386_TLS_DESC_CALL:
1073 break;
1074
1075 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1076 if (optimized_type == tls::TLSOPT_NONE)
1077 {
1078 // Create a GOT entry for the module index.
1079 target->got_mod_index_entry(symtab, layout, object);
1080 }
1081 else if (optimized_type != tls::TLSOPT_TO_LE)
1082 unsupported_reloc_local(object, r_type);
1083 break;
1084
1085 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1086 break;
1087
1088 case elfcpp::R_386_TLS_IE: // Initial-exec
1089 case elfcpp::R_386_TLS_IE_32:
1090 case elfcpp::R_386_TLS_GOTIE:
1091 layout->set_has_static_tls();
1092 if (optimized_type == tls::TLSOPT_NONE)
1093 {
1094 // For the R_386_TLS_IE relocation, we need to create a
1095 // dynamic relocation when building a shared library.
1096 if (r_type == elfcpp::R_386_TLS_IE
1097 && parameters->options().shared())
1098 {
1099 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1100 unsigned int r_sym
1101 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1102 rel_dyn->add_local_relative(object, r_sym,
1103 elfcpp::R_386_RELATIVE,
1104 output_section, data_shndx,
1105 reloc.get_r_offset());
1106 }
1107 // Create a GOT entry for the tp-relative offset.
1108 Output_data_got<32, false>* got
1109 = target->got_section(symtab, layout);
1110 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1111 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1112 ? elfcpp::R_386_TLS_TPOFF32
1113 : elfcpp::R_386_TLS_TPOFF);
1114 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1115 ? GOT_TYPE_TLS_OFFSET
1116 : GOT_TYPE_TLS_NOFFSET);
1117 got->add_local_with_rel(object, r_sym, got_type,
1118 target->rel_dyn_section(layout),
1119 dyn_r_type);
1120 }
1121 else if (optimized_type != tls::TLSOPT_TO_LE)
1122 unsupported_reloc_local(object, r_type);
1123 break;
1124
1125 case elfcpp::R_386_TLS_LE: // Local-exec
1126 case elfcpp::R_386_TLS_LE_32:
1127 layout->set_has_static_tls();
1128 if (output_is_shared)
1129 {
1130 // We need to create a dynamic relocation.
1131 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1132 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1133 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1134 ? elfcpp::R_386_TLS_TPOFF32
1135 : elfcpp::R_386_TLS_TPOFF);
1136 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1137 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1138 data_shndx, reloc.get_r_offset());
1139 }
1140 break;
1141
1142 default:
1143 gold_unreachable();
1144 }
1145 }
1146 break;
1147
1148 case elfcpp::R_386_32PLT:
1149 case elfcpp::R_386_TLS_GD_32:
1150 case elfcpp::R_386_TLS_GD_PUSH:
1151 case elfcpp::R_386_TLS_GD_CALL:
1152 case elfcpp::R_386_TLS_GD_POP:
1153 case elfcpp::R_386_TLS_LDM_32:
1154 case elfcpp::R_386_TLS_LDM_PUSH:
1155 case elfcpp::R_386_TLS_LDM_CALL:
1156 case elfcpp::R_386_TLS_LDM_POP:
1157 case elfcpp::R_386_USED_BY_INTEL_200:
1158 default:
1159 unsupported_reloc_local(object, r_type);
1160 break;
1161 }
1162 }
1163
1164 // Report an unsupported relocation against a global symbol.
1165
1166 void
1167 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1168 unsigned int r_type,
1169 Symbol* gsym)
1170 {
1171 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1172 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1173 }
1174
1175 // Scan a relocation for a global symbol.
1176
1177 inline void
1178 Target_i386::Scan::global(const General_options&,
1179 Symbol_table* symtab,
1180 Layout* layout,
1181 Target_i386* target,
1182 Sized_relobj<32, false>* object,
1183 unsigned int data_shndx,
1184 Output_section* output_section,
1185 const elfcpp::Rel<32, false>& reloc,
1186 unsigned int r_type,
1187 Symbol* gsym)
1188 {
1189 switch (r_type)
1190 {
1191 case elfcpp::R_386_NONE:
1192 case elfcpp::R_386_GNU_VTINHERIT:
1193 case elfcpp::R_386_GNU_VTENTRY:
1194 break;
1195
1196 case elfcpp::R_386_32:
1197 case elfcpp::R_386_16:
1198 case elfcpp::R_386_8:
1199 {
1200 // Make a PLT entry if necessary.
1201 if (gsym->needs_plt_entry())
1202 {
1203 target->make_plt_entry(symtab, layout, gsym);
1204 // Since this is not a PC-relative relocation, we may be
1205 // taking the address of a function. In that case we need to
1206 // set the entry in the dynamic symbol table to the address of
1207 // the PLT entry.
1208 if (gsym->is_from_dynobj() && !parameters->options().shared())
1209 gsym->set_needs_dynsym_value();
1210 }
1211 // Make a dynamic relocation if necessary.
1212 if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1213 {
1214 if (gsym->may_need_copy_reloc())
1215 {
1216 target->copy_reloc(symtab, layout, object,
1217 data_shndx, output_section, gsym, reloc);
1218 }
1219 else if (r_type == elfcpp::R_386_32
1220 && gsym->can_use_relative_reloc(false))
1221 {
1222 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1223 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1224 output_section, object,
1225 data_shndx, reloc.get_r_offset());
1226 }
1227 else
1228 {
1229 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1230 rel_dyn->add_global(gsym, r_type, output_section, object,
1231 data_shndx, reloc.get_r_offset());
1232 }
1233 }
1234 }
1235 break;
1236
1237 case elfcpp::R_386_PC32:
1238 case elfcpp::R_386_PC16:
1239 case elfcpp::R_386_PC8:
1240 {
1241 // Make a PLT entry if necessary.
1242 if (gsym->needs_plt_entry())
1243 {
1244 // These relocations are used for function calls only in
1245 // non-PIC code. For a 32-bit relocation in a shared library,
1246 // we'll need a text relocation anyway, so we can skip the
1247 // PLT entry and let the dynamic linker bind the call directly
1248 // to the target. For smaller relocations, we should use a
1249 // PLT entry to ensure that the call can reach.
1250 if (!parameters->options().shared()
1251 || r_type != elfcpp::R_386_PC32)
1252 target->make_plt_entry(symtab, layout, gsym);
1253 }
1254 // Make a dynamic relocation if necessary.
1255 int flags = Symbol::NON_PIC_REF;
1256 if (gsym->type() == elfcpp::STT_FUNC)
1257 flags |= Symbol::FUNCTION_CALL;
1258 if (gsym->needs_dynamic_reloc(flags))
1259 {
1260 if (gsym->may_need_copy_reloc())
1261 {
1262 target->copy_reloc(symtab, layout, object,
1263 data_shndx, output_section, gsym, reloc);
1264 }
1265 else
1266 {
1267 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1268 rel_dyn->add_global(gsym, r_type, output_section, object,
1269 data_shndx, reloc.get_r_offset());
1270 }
1271 }
1272 }
1273 break;
1274
1275 case elfcpp::R_386_GOT32:
1276 {
1277 // The symbol requires a GOT entry.
1278 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1279 if (gsym->final_value_is_known())
1280 got->add_global(gsym, GOT_TYPE_STANDARD);
1281 else
1282 {
1283 // If this symbol is not fully resolved, we need to add a
1284 // GOT entry with a dynamic relocation.
1285 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1286 if (gsym->is_from_dynobj()
1287 || gsym->is_undefined()
1288 || gsym->is_preemptible())
1289 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1290 rel_dyn, elfcpp::R_386_GLOB_DAT);
1291 else
1292 {
1293 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1294 rel_dyn->add_global_relative(
1295 gsym, elfcpp::R_386_RELATIVE, got,
1296 gsym->got_offset(GOT_TYPE_STANDARD));
1297 }
1298 }
1299 }
1300 break;
1301
1302 case elfcpp::R_386_PLT32:
1303 // If the symbol is fully resolved, this is just a PC32 reloc.
1304 // Otherwise we need a PLT entry.
1305 if (gsym->final_value_is_known())
1306 break;
1307 // If building a shared library, we can also skip the PLT entry
1308 // if the symbol is defined in the output file and is protected
1309 // or hidden.
1310 if (gsym->is_defined()
1311 && !gsym->is_from_dynobj()
1312 && !gsym->is_preemptible())
1313 break;
1314 target->make_plt_entry(symtab, layout, gsym);
1315 break;
1316
1317 case elfcpp::R_386_GOTOFF:
1318 case elfcpp::R_386_GOTPC:
1319 // We need a GOT section.
1320 target->got_section(symtab, layout);
1321 break;
1322
1323 // These are relocations which should only be seen by the
1324 // dynamic linker, and should never be seen here.
1325 case elfcpp::R_386_COPY:
1326 case elfcpp::R_386_GLOB_DAT:
1327 case elfcpp::R_386_JUMP_SLOT:
1328 case elfcpp::R_386_RELATIVE:
1329 case elfcpp::R_386_TLS_TPOFF:
1330 case elfcpp::R_386_TLS_DTPMOD32:
1331 case elfcpp::R_386_TLS_DTPOFF32:
1332 case elfcpp::R_386_TLS_TPOFF32:
1333 case elfcpp::R_386_TLS_DESC:
1334 gold_error(_("%s: unexpected reloc %u in object file"),
1335 object->name().c_str(), r_type);
1336 break;
1337
1338 // These are initial tls relocs, which are expected when
1339 // linking.
1340 case elfcpp::R_386_TLS_GD: // Global-dynamic
1341 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1342 case elfcpp::R_386_TLS_DESC_CALL:
1343 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1344 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1345 case elfcpp::R_386_TLS_IE: // Initial-exec
1346 case elfcpp::R_386_TLS_IE_32:
1347 case elfcpp::R_386_TLS_GOTIE:
1348 case elfcpp::R_386_TLS_LE: // Local-exec
1349 case elfcpp::R_386_TLS_LE_32:
1350 {
1351 const bool is_final = gsym->final_value_is_known();
1352 const tls::Tls_optimization optimized_type
1353 = Target_i386::optimize_tls_reloc(is_final, r_type);
1354 switch (r_type)
1355 {
1356 case elfcpp::R_386_TLS_GD: // Global-dynamic
1357 if (optimized_type == tls::TLSOPT_NONE)
1358 {
1359 // Create a pair of GOT entries for the module index and
1360 // dtv-relative offset.
1361 Output_data_got<32, false>* got
1362 = target->got_section(symtab, layout);
1363 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1364 target->rel_dyn_section(layout),
1365 elfcpp::R_386_TLS_DTPMOD32,
1366 elfcpp::R_386_TLS_DTPOFF32);
1367 }
1368 else if (optimized_type == tls::TLSOPT_TO_IE)
1369 {
1370 // Create a GOT entry for the tp-relative offset.
1371 Output_data_got<32, false>* got
1372 = target->got_section(symtab, layout);
1373 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1374 target->rel_dyn_section(layout),
1375 elfcpp::R_386_TLS_TPOFF);
1376 }
1377 else if (optimized_type != tls::TLSOPT_TO_LE)
1378 unsupported_reloc_global(object, r_type, gsym);
1379 break;
1380
1381 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1382 target->define_tls_base_symbol(symtab, layout);
1383 if (optimized_type == tls::TLSOPT_NONE)
1384 {
1385 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1386 Output_data_got<32, false>* got
1387 = target->got_section(symtab, layout);
1388 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC,
1389 target->rel_dyn_section(layout),
1390 elfcpp::R_386_TLS_DESC, 0);
1391 }
1392 else if (optimized_type == tls::TLSOPT_TO_IE)
1393 {
1394 // Create a GOT entry for the tp-relative offset.
1395 Output_data_got<32, false>* got
1396 = target->got_section(symtab, layout);
1397 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1398 target->rel_dyn_section(layout),
1399 elfcpp::R_386_TLS_TPOFF);
1400 }
1401 else if (optimized_type != tls::TLSOPT_TO_LE)
1402 unsupported_reloc_global(object, r_type, gsym);
1403 break;
1404
1405 case elfcpp::R_386_TLS_DESC_CALL:
1406 break;
1407
1408 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1409 if (optimized_type == tls::TLSOPT_NONE)
1410 {
1411 // Create a GOT entry for the module index.
1412 target->got_mod_index_entry(symtab, layout, object);
1413 }
1414 else if (optimized_type != tls::TLSOPT_TO_LE)
1415 unsupported_reloc_global(object, r_type, gsym);
1416 break;
1417
1418 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1419 break;
1420
1421 case elfcpp::R_386_TLS_IE: // Initial-exec
1422 case elfcpp::R_386_TLS_IE_32:
1423 case elfcpp::R_386_TLS_GOTIE:
1424 layout->set_has_static_tls();
1425 if (optimized_type == tls::TLSOPT_NONE)
1426 {
1427 // For the R_386_TLS_IE relocation, we need to create a
1428 // dynamic relocation when building a shared library.
1429 if (r_type == elfcpp::R_386_TLS_IE
1430 && parameters->options().shared())
1431 {
1432 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1433 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1434 output_section, object,
1435 data_shndx,
1436 reloc.get_r_offset());
1437 }
1438 // Create a GOT entry for the tp-relative offset.
1439 Output_data_got<32, false>* got
1440 = target->got_section(symtab, layout);
1441 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1442 ? elfcpp::R_386_TLS_TPOFF32
1443 : elfcpp::R_386_TLS_TPOFF);
1444 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1445 ? GOT_TYPE_TLS_OFFSET
1446 : GOT_TYPE_TLS_NOFFSET);
1447 got->add_global_with_rel(gsym, got_type,
1448 target->rel_dyn_section(layout),
1449 dyn_r_type);
1450 }
1451 else if (optimized_type != tls::TLSOPT_TO_LE)
1452 unsupported_reloc_global(object, r_type, gsym);
1453 break;
1454
1455 case elfcpp::R_386_TLS_LE: // Local-exec
1456 case elfcpp::R_386_TLS_LE_32:
1457 layout->set_has_static_tls();
1458 if (parameters->options().shared())
1459 {
1460 // We need to create a dynamic relocation.
1461 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1462 ? elfcpp::R_386_TLS_TPOFF32
1463 : elfcpp::R_386_TLS_TPOFF);
1464 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1465 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1466 data_shndx, reloc.get_r_offset());
1467 }
1468 break;
1469
1470 default:
1471 gold_unreachable();
1472 }
1473 }
1474 break;
1475
1476 case elfcpp::R_386_32PLT:
1477 case elfcpp::R_386_TLS_GD_32:
1478 case elfcpp::R_386_TLS_GD_PUSH:
1479 case elfcpp::R_386_TLS_GD_CALL:
1480 case elfcpp::R_386_TLS_GD_POP:
1481 case elfcpp::R_386_TLS_LDM_32:
1482 case elfcpp::R_386_TLS_LDM_PUSH:
1483 case elfcpp::R_386_TLS_LDM_CALL:
1484 case elfcpp::R_386_TLS_LDM_POP:
1485 case elfcpp::R_386_USED_BY_INTEL_200:
1486 default:
1487 unsupported_reloc_global(object, r_type, gsym);
1488 break;
1489 }
1490 }
1491
1492 // Process relocations for gc.
1493
1494 void
1495 Target_i386::gc_process_relocs(const General_options& options,
1496 Symbol_table* symtab,
1497 Layout* layout,
1498 Sized_relobj<32, false>* object,
1499 unsigned int data_shndx,
1500 unsigned int,
1501 const unsigned char* prelocs,
1502 size_t reloc_count,
1503 Output_section* output_section,
1504 bool needs_special_offset_handling,
1505 size_t local_symbol_count,
1506 const unsigned char* plocal_symbols)
1507 {
1508 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1509 Target_i386::Scan>(
1510 options,
1511 symtab,
1512 layout,
1513 this,
1514 object,
1515 data_shndx,
1516 prelocs,
1517 reloc_count,
1518 output_section,
1519 needs_special_offset_handling,
1520 local_symbol_count,
1521 plocal_symbols);
1522 }
1523
1524 // Scan relocations for a section.
1525
1526 void
1527 Target_i386::scan_relocs(const General_options& options,
1528 Symbol_table* symtab,
1529 Layout* layout,
1530 Sized_relobj<32, false>* object,
1531 unsigned int data_shndx,
1532 unsigned int sh_type,
1533 const unsigned char* prelocs,
1534 size_t reloc_count,
1535 Output_section* output_section,
1536 bool needs_special_offset_handling,
1537 size_t local_symbol_count,
1538 const unsigned char* plocal_symbols)
1539 {
1540 if (sh_type == elfcpp::SHT_RELA)
1541 {
1542 gold_error(_("%s: unsupported RELA reloc section"),
1543 object->name().c_str());
1544 return;
1545 }
1546
1547 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1548 Target_i386::Scan>(
1549 options,
1550 symtab,
1551 layout,
1552 this,
1553 object,
1554 data_shndx,
1555 prelocs,
1556 reloc_count,
1557 output_section,
1558 needs_special_offset_handling,
1559 local_symbol_count,
1560 plocal_symbols);
1561 }
1562
1563 // Finalize the sections.
1564
1565 void
1566 Target_i386::do_finalize_sections(Layout* layout)
1567 {
1568 // Fill in some more dynamic tags.
1569 Output_data_dynamic* const odyn = layout->dynamic_data();
1570 if (odyn != NULL)
1571 {
1572 if (this->got_plt_ != NULL)
1573 odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1574
1575 if (this->plt_ != NULL)
1576 {
1577 const Output_data* od = this->plt_->rel_plt();
1578 odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1579 odyn->add_section_address(elfcpp::DT_JMPREL, od);
1580 odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1581 }
1582
1583 if (this->rel_dyn_ != NULL)
1584 {
1585 const Output_data* od = this->rel_dyn_;
1586 odyn->add_section_address(elfcpp::DT_REL, od);
1587 odyn->add_section_size(elfcpp::DT_RELSZ, od);
1588 odyn->add_constant(elfcpp::DT_RELENT,
1589 elfcpp::Elf_sizes<32>::rel_size);
1590 }
1591
1592 if (!parameters->options().shared())
1593 {
1594 // The value of the DT_DEBUG tag is filled in by the dynamic
1595 // linker at run time, and used by the debugger.
1596 odyn->add_constant(elfcpp::DT_DEBUG, 0);
1597 }
1598 }
1599
1600 // Emit any relocs we saved in an attempt to avoid generating COPY
1601 // relocs.
1602 if (this->copy_relocs_.any_saved_relocs())
1603 this->copy_relocs_.emit(this->rel_dyn_section(layout));
1604 }
1605
1606 // Return whether a direct absolute static relocation needs to be applied.
1607 // In cases where Scan::local() or Scan::global() has created
1608 // a dynamic relocation other than R_386_RELATIVE, the addend
1609 // of the relocation is carried in the data, and we must not
1610 // apply the static relocation.
1611
1612 inline bool
1613 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1614 int ref_flags,
1615 bool is_32bit,
1616 Output_section* output_section)
1617 {
1618 // If the output section is not allocated, then we didn't call
1619 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1620 // the reloc here.
1621 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1622 return true;
1623
1624 // For local symbols, we will have created a non-RELATIVE dynamic
1625 // relocation only if (a) the output is position independent,
1626 // (b) the relocation is absolute (not pc- or segment-relative), and
1627 // (c) the relocation is not 32 bits wide.
1628 if (gsym == NULL)
1629 return !(parameters->options().output_is_position_independent()
1630 && (ref_flags & Symbol::ABSOLUTE_REF)
1631 && !is_32bit);
1632
1633 // For global symbols, we use the same helper routines used in the
1634 // scan pass. If we did not create a dynamic relocation, or if we
1635 // created a RELATIVE dynamic relocation, we should apply the static
1636 // relocation.
1637 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1638 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1639 && gsym->can_use_relative_reloc(ref_flags
1640 & Symbol::FUNCTION_CALL);
1641 return !has_dyn || is_rel;
1642 }
1643
1644 // Perform a relocation.
1645
1646 inline bool
1647 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1648 Target_i386* target,
1649 Output_section *output_section,
1650 size_t relnum,
1651 const elfcpp::Rel<32, false>& rel,
1652 unsigned int r_type,
1653 const Sized_symbol<32>* gsym,
1654 const Symbol_value<32>* psymval,
1655 unsigned char* view,
1656 elfcpp::Elf_types<32>::Elf_Addr address,
1657 section_size_type view_size)
1658 {
1659 if (this->skip_call_tls_get_addr_)
1660 {
1661 if ((r_type != elfcpp::R_386_PLT32
1662 && r_type != elfcpp::R_386_PC32)
1663 || gsym == NULL
1664 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1665 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1666 _("missing expected TLS relocation"));
1667 else
1668 {
1669 this->skip_call_tls_get_addr_ = false;
1670 return false;
1671 }
1672 }
1673
1674 // Pick the value to use for symbols defined in shared objects.
1675 Symbol_value<32> symval;
1676 if (gsym != NULL
1677 && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1678 || r_type == elfcpp::R_386_PC16
1679 || r_type == elfcpp::R_386_PC32))
1680 {
1681 symval.set_output_value(target->plt_section()->address()
1682 + gsym->plt_offset());
1683 psymval = &symval;
1684 }
1685
1686 const Sized_relobj<32, false>* object = relinfo->object;
1687
1688 // Get the GOT offset if needed.
1689 // The GOT pointer points to the end of the GOT section.
1690 // We need to subtract the size of the GOT section to get
1691 // the actual offset to use in the relocation.
1692 bool have_got_offset = false;
1693 unsigned int got_offset = 0;
1694 switch (r_type)
1695 {
1696 case elfcpp::R_386_GOT32:
1697 if (gsym != NULL)
1698 {
1699 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1700 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1701 - target->got_size());
1702 }
1703 else
1704 {
1705 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1706 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1707 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1708 - target->got_size());
1709 }
1710 have_got_offset = true;
1711 break;
1712
1713 default:
1714 break;
1715 }
1716
1717 switch (r_type)
1718 {
1719 case elfcpp::R_386_NONE:
1720 case elfcpp::R_386_GNU_VTINHERIT:
1721 case elfcpp::R_386_GNU_VTENTRY:
1722 break;
1723
1724 case elfcpp::R_386_32:
1725 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1726 output_section))
1727 Relocate_functions<32, false>::rel32(view, object, psymval);
1728 break;
1729
1730 case elfcpp::R_386_PC32:
1731 {
1732 int ref_flags = Symbol::NON_PIC_REF;
1733 if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1734 ref_flags |= Symbol::FUNCTION_CALL;
1735 if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1736 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1737 }
1738 break;
1739
1740 case elfcpp::R_386_16:
1741 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1742 output_section))
1743 Relocate_functions<32, false>::rel16(view, object, psymval);
1744 break;
1745
1746 case elfcpp::R_386_PC16:
1747 {
1748 int ref_flags = Symbol::NON_PIC_REF;
1749 if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1750 ref_flags |= Symbol::FUNCTION_CALL;
1751 if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1752 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1753 }
1754 break;
1755
1756 case elfcpp::R_386_8:
1757 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1758 output_section))
1759 Relocate_functions<32, false>::rel8(view, object, psymval);
1760 break;
1761
1762 case elfcpp::R_386_PC8:
1763 {
1764 int ref_flags = Symbol::NON_PIC_REF;
1765 if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1766 ref_flags |= Symbol::FUNCTION_CALL;
1767 if (should_apply_static_reloc(gsym, ref_flags, false,
1768 output_section))
1769 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1770 }
1771 break;
1772
1773 case elfcpp::R_386_PLT32:
1774 gold_assert(gsym == NULL
1775 || gsym->has_plt_offset()
1776 || gsym->final_value_is_known()
1777 || (gsym->is_defined()
1778 && !gsym->is_from_dynobj()
1779 && !gsym->is_preemptible()));
1780 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1781 break;
1782
1783 case elfcpp::R_386_GOT32:
1784 gold_assert(have_got_offset);
1785 Relocate_functions<32, false>::rel32(view, got_offset);
1786 break;
1787
1788 case elfcpp::R_386_GOTOFF:
1789 {
1790 elfcpp::Elf_types<32>::Elf_Addr value;
1791 value = (psymval->value(object, 0)
1792 - target->got_plt_section()->address());
1793 Relocate_functions<32, false>::rel32(view, value);
1794 }
1795 break;
1796
1797 case elfcpp::R_386_GOTPC:
1798 {
1799 elfcpp::Elf_types<32>::Elf_Addr value;
1800 value = target->got_plt_section()->address();
1801 Relocate_functions<32, false>::pcrel32(view, value, address);
1802 }
1803 break;
1804
1805 case elfcpp::R_386_COPY:
1806 case elfcpp::R_386_GLOB_DAT:
1807 case elfcpp::R_386_JUMP_SLOT:
1808 case elfcpp::R_386_RELATIVE:
1809 // These are outstanding tls relocs, which are unexpected when
1810 // linking.
1811 case elfcpp::R_386_TLS_TPOFF:
1812 case elfcpp::R_386_TLS_DTPMOD32:
1813 case elfcpp::R_386_TLS_DTPOFF32:
1814 case elfcpp::R_386_TLS_TPOFF32:
1815 case elfcpp::R_386_TLS_DESC:
1816 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1817 _("unexpected reloc %u in object file"),
1818 r_type);
1819 break;
1820
1821 // These are initial tls relocs, which are expected when
1822 // linking.
1823 case elfcpp::R_386_TLS_GD: // Global-dynamic
1824 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1825 case elfcpp::R_386_TLS_DESC_CALL:
1826 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1827 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1828 case elfcpp::R_386_TLS_IE: // Initial-exec
1829 case elfcpp::R_386_TLS_IE_32:
1830 case elfcpp::R_386_TLS_GOTIE:
1831 case elfcpp::R_386_TLS_LE: // Local-exec
1832 case elfcpp::R_386_TLS_LE_32:
1833 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1834 view, address, view_size);
1835 break;
1836
1837 case elfcpp::R_386_32PLT:
1838 case elfcpp::R_386_TLS_GD_32:
1839 case elfcpp::R_386_TLS_GD_PUSH:
1840 case elfcpp::R_386_TLS_GD_CALL:
1841 case elfcpp::R_386_TLS_GD_POP:
1842 case elfcpp::R_386_TLS_LDM_32:
1843 case elfcpp::R_386_TLS_LDM_PUSH:
1844 case elfcpp::R_386_TLS_LDM_CALL:
1845 case elfcpp::R_386_TLS_LDM_POP:
1846 case elfcpp::R_386_USED_BY_INTEL_200:
1847 default:
1848 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1849 _("unsupported reloc %u"),
1850 r_type);
1851 break;
1852 }
1853
1854 return true;
1855 }
1856
1857 // Perform a TLS relocation.
1858
1859 inline void
1860 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1861 Target_i386* target,
1862 size_t relnum,
1863 const elfcpp::Rel<32, false>& rel,
1864 unsigned int r_type,
1865 const Sized_symbol<32>* gsym,
1866 const Symbol_value<32>* psymval,
1867 unsigned char* view,
1868 elfcpp::Elf_types<32>::Elf_Addr,
1869 section_size_type view_size)
1870 {
1871 Output_segment* tls_segment = relinfo->layout->tls_segment();
1872
1873 const Sized_relobj<32, false>* object = relinfo->object;
1874
1875 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1876
1877 const bool is_final =
1878 (gsym == NULL
1879 ? !parameters->options().output_is_position_independent()
1880 : gsym->final_value_is_known());
1881 const tls::Tls_optimization optimized_type
1882 = Target_i386::optimize_tls_reloc(is_final, r_type);
1883 switch (r_type)
1884 {
1885 case elfcpp::R_386_TLS_GD: // Global-dynamic
1886 if (optimized_type == tls::TLSOPT_TO_LE)
1887 {
1888 gold_assert(tls_segment != NULL);
1889 this->tls_gd_to_le(relinfo, relnum, tls_segment,
1890 rel, r_type, value, view,
1891 view_size);
1892 break;
1893 }
1894 else
1895 {
1896 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1897 ? GOT_TYPE_TLS_NOFFSET
1898 : GOT_TYPE_TLS_PAIR);
1899 unsigned int got_offset;
1900 if (gsym != NULL)
1901 {
1902 gold_assert(gsym->has_got_offset(got_type));
1903 got_offset = gsym->got_offset(got_type) - target->got_size();
1904 }
1905 else
1906 {
1907 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1908 gold_assert(object->local_has_got_offset(r_sym, got_type));
1909 got_offset = (object->local_got_offset(r_sym, got_type)
1910 - target->got_size());
1911 }
1912 if (optimized_type == tls::TLSOPT_TO_IE)
1913 {
1914 gold_assert(tls_segment != NULL);
1915 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1916 got_offset, view, view_size);
1917 break;
1918 }
1919 else if (optimized_type == tls::TLSOPT_NONE)
1920 {
1921 // Relocate the field with the offset of the pair of GOT
1922 // entries.
1923 Relocate_functions<32, false>::rel32(view, got_offset);
1924 break;
1925 }
1926 }
1927 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1928 _("unsupported reloc %u"),
1929 r_type);
1930 break;
1931
1932 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1933 case elfcpp::R_386_TLS_DESC_CALL:
1934 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1935 if (optimized_type == tls::TLSOPT_TO_LE)
1936 {
1937 gold_assert(tls_segment != NULL);
1938 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
1939 rel, r_type, value, view,
1940 view_size);
1941 break;
1942 }
1943 else
1944 {
1945 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1946 ? GOT_TYPE_TLS_NOFFSET
1947 : GOT_TYPE_TLS_DESC);
1948 unsigned int got_offset;
1949 if (gsym != NULL)
1950 {
1951 gold_assert(gsym->has_got_offset(got_type));
1952 got_offset = gsym->got_offset(got_type) - target->got_size();
1953 }
1954 else
1955 {
1956 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1957 gold_assert(object->local_has_got_offset(r_sym, got_type));
1958 got_offset = (object->local_got_offset(r_sym, got_type)
1959 - target->got_size());
1960 }
1961 if (optimized_type == tls::TLSOPT_TO_IE)
1962 {
1963 gold_assert(tls_segment != NULL);
1964 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1965 got_offset, view, view_size);
1966 break;
1967 }
1968 else if (optimized_type == tls::TLSOPT_NONE)
1969 {
1970 if (r_type == elfcpp::R_386_TLS_GOTDESC)
1971 {
1972 // Relocate the field with the offset of the pair of GOT
1973 // entries.
1974 Relocate_functions<32, false>::rel32(view, got_offset);
1975 }
1976 break;
1977 }
1978 }
1979 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1980 _("unsupported reloc %u"),
1981 r_type);
1982 break;
1983
1984 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1985 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1986 {
1987 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1988 _("both SUN and GNU model "
1989 "TLS relocations"));
1990 break;
1991 }
1992 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1993 if (optimized_type == tls::TLSOPT_TO_LE)
1994 {
1995 gold_assert(tls_segment != NULL);
1996 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1997 value, view, view_size);
1998 break;
1999 }
2000 else if (optimized_type == tls::TLSOPT_NONE)
2001 {
2002 // Relocate the field with the offset of the GOT entry for
2003 // the module index.
2004 unsigned int got_offset;
2005 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2006 - target->got_size());
2007 Relocate_functions<32, false>::rel32(view, got_offset);
2008 break;
2009 }
2010 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2011 _("unsupported reloc %u"),
2012 r_type);
2013 break;
2014
2015 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2016 if (optimized_type == tls::TLSOPT_TO_LE)
2017 {
2018 // This reloc can appear in debugging sections, in which
2019 // case we must not convert to local-exec. We decide what
2020 // to do based on whether the section is marked as
2021 // containing executable code. That is what the GNU linker
2022 // does as well.
2023 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2024 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2025 {
2026 gold_assert(tls_segment != NULL);
2027 value -= tls_segment->memsz();
2028 }
2029 }
2030 Relocate_functions<32, false>::rel32(view, value);
2031 break;
2032
2033 case elfcpp::R_386_TLS_IE: // Initial-exec
2034 case elfcpp::R_386_TLS_GOTIE:
2035 case elfcpp::R_386_TLS_IE_32:
2036 if (optimized_type == tls::TLSOPT_TO_LE)
2037 {
2038 gold_assert(tls_segment != NULL);
2039 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2040 rel, r_type, value, view,
2041 view_size);
2042 break;
2043 }
2044 else if (optimized_type == tls::TLSOPT_NONE)
2045 {
2046 // Relocate the field with the offset of the GOT entry for
2047 // the tp-relative offset of the symbol.
2048 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2049 ? GOT_TYPE_TLS_OFFSET
2050 : GOT_TYPE_TLS_NOFFSET);
2051 unsigned int got_offset;
2052 if (gsym != NULL)
2053 {
2054 gold_assert(gsym->has_got_offset(got_type));
2055 got_offset = gsym->got_offset(got_type);
2056 }
2057 else
2058 {
2059 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2060 gold_assert(object->local_has_got_offset(r_sym, got_type));
2061 got_offset = object->local_got_offset(r_sym, got_type);
2062 }
2063 // For the R_386_TLS_IE relocation, we need to apply the
2064 // absolute address of the GOT entry.
2065 if (r_type == elfcpp::R_386_TLS_IE)
2066 got_offset += target->got_plt_section()->address();
2067 // All GOT offsets are relative to the end of the GOT.
2068 got_offset -= target->got_size();
2069 Relocate_functions<32, false>::rel32(view, got_offset);
2070 break;
2071 }
2072 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2073 _("unsupported reloc %u"),
2074 r_type);
2075 break;
2076
2077 case elfcpp::R_386_TLS_LE: // Local-exec
2078 // If we're creating a shared library, a dynamic relocation will
2079 // have been created for this location, so do not apply it now.
2080 if (!parameters->options().shared())
2081 {
2082 gold_assert(tls_segment != NULL);
2083 value -= tls_segment->memsz();
2084 Relocate_functions<32, false>::rel32(view, value);
2085 }
2086 break;
2087
2088 case elfcpp::R_386_TLS_LE_32:
2089 // If we're creating a shared library, a dynamic relocation will
2090 // have been created for this location, so do not apply it now.
2091 if (!parameters->options().shared())
2092 {
2093 gold_assert(tls_segment != NULL);
2094 value = tls_segment->memsz() - value;
2095 Relocate_functions<32, false>::rel32(view, value);
2096 }
2097 break;
2098 }
2099 }
2100
2101 // Do a relocation in which we convert a TLS General-Dynamic to a
2102 // Local-Exec.
2103
2104 inline void
2105 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2106 size_t relnum,
2107 Output_segment* tls_segment,
2108 const elfcpp::Rel<32, false>& rel,
2109 unsigned int,
2110 elfcpp::Elf_types<32>::Elf_Addr value,
2111 unsigned char* view,
2112 section_size_type view_size)
2113 {
2114 // leal foo(,%reg,1),%eax; call ___tls_get_addr
2115 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2116 // leal foo(%reg),%eax; call ___tls_get_addr
2117 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2118
2119 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2120 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2121
2122 unsigned char op1 = view[-1];
2123 unsigned char op2 = view[-2];
2124
2125 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2126 op2 == 0x8d || op2 == 0x04);
2127 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2128
2129 int roff = 5;
2130
2131 if (op2 == 0x04)
2132 {
2133 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2134 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2135 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2136 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2137 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2138 }
2139 else
2140 {
2141 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2142 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2143 if (rel.get_r_offset() + 9 < view_size
2144 && view[9] == 0x90)
2145 {
2146 // There is a trailing nop. Use the size byte subl.
2147 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2148 roff = 6;
2149 }
2150 else
2151 {
2152 // Use the five byte subl.
2153 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2154 }
2155 }
2156
2157 value = tls_segment->memsz() - value;
2158 Relocate_functions<32, false>::rel32(view + roff, value);
2159
2160 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2161 // We can skip it.
2162 this->skip_call_tls_get_addr_ = true;
2163 }
2164
2165 // Do a relocation in which we convert a TLS General-Dynamic to an
2166 // Initial-Exec.
2167
2168 inline void
2169 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2170 size_t relnum,
2171 Output_segment*,
2172 const elfcpp::Rel<32, false>& rel,
2173 unsigned int,
2174 elfcpp::Elf_types<32>::Elf_Addr value,
2175 unsigned char* view,
2176 section_size_type view_size)
2177 {
2178 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2179 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2180
2181 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2182 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2183
2184 unsigned char op1 = view[-1];
2185 unsigned char op2 = view[-2];
2186
2187 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2188 op2 == 0x8d || op2 == 0x04);
2189 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2190
2191 int roff = 5;
2192
2193 // FIXME: For now, support only the first (SIB) form.
2194 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2195
2196 if (op2 == 0x04)
2197 {
2198 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2199 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2200 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2201 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2202 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2203 }
2204 else
2205 {
2206 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2207 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2208 if (rel.get_r_offset() + 9 < view_size
2209 && view[9] == 0x90)
2210 {
2211 // FIXME: This is not the right instruction sequence.
2212 // There is a trailing nop. Use the size byte subl.
2213 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2214 roff = 6;
2215 }
2216 else
2217 {
2218 // FIXME: This is not the right instruction sequence.
2219 // Use the five byte subl.
2220 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2221 }
2222 }
2223
2224 Relocate_functions<32, false>::rel32(view + roff, value);
2225
2226 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2227 // We can skip it.
2228 this->skip_call_tls_get_addr_ = true;
2229 }
2230
2231 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2232 // General-Dynamic to a Local-Exec.
2233
2234 inline void
2235 Target_i386::Relocate::tls_desc_gd_to_le(
2236 const Relocate_info<32, false>* relinfo,
2237 size_t relnum,
2238 Output_segment* tls_segment,
2239 const elfcpp::Rel<32, false>& rel,
2240 unsigned int r_type,
2241 elfcpp::Elf_types<32>::Elf_Addr value,
2242 unsigned char* view,
2243 section_size_type view_size)
2244 {
2245 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2246 {
2247 // leal foo@TLSDESC(%ebx), %eax
2248 // ==> leal foo@NTPOFF, %eax
2249 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2250 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2251 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2252 view[-2] == 0x8d && view[-1] == 0x83);
2253 view[-1] = 0x05;
2254 value -= tls_segment->memsz();
2255 Relocate_functions<32, false>::rel32(view, value);
2256 }
2257 else
2258 {
2259 // call *foo@TLSCALL(%eax)
2260 // ==> nop; nop
2261 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2262 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2263 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2264 view[0] == 0xff && view[1] == 0x10);
2265 view[0] = 0x66;
2266 view[1] = 0x90;
2267 }
2268 }
2269
2270 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2271 // General-Dynamic to an Initial-Exec.
2272
2273 inline void
2274 Target_i386::Relocate::tls_desc_gd_to_ie(
2275 const Relocate_info<32, false>* relinfo,
2276 size_t relnum,
2277 Output_segment*,
2278 const elfcpp::Rel<32, false>& rel,
2279 unsigned int r_type,
2280 elfcpp::Elf_types<32>::Elf_Addr value,
2281 unsigned char* view,
2282 section_size_type view_size)
2283 {
2284 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2285 {
2286 // leal foo@TLSDESC(%ebx), %eax
2287 // ==> movl foo@GOTNTPOFF(%ebx), %eax
2288 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2289 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2290 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2291 view[-2] == 0x8d && view[-1] == 0x83);
2292 view[-2] = 0x8b;
2293 Relocate_functions<32, false>::rel32(view, value);
2294 }
2295 else
2296 {
2297 // call *foo@TLSCALL(%eax)
2298 // ==> nop; nop
2299 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2300 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2301 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2302 view[0] == 0xff && view[1] == 0x10);
2303 view[0] = 0x66;
2304 view[1] = 0x90;
2305 }
2306 }
2307
2308 // Do a relocation in which we convert a TLS Local-Dynamic to a
2309 // Local-Exec.
2310
2311 inline void
2312 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2313 size_t relnum,
2314 Output_segment*,
2315 const elfcpp::Rel<32, false>& rel,
2316 unsigned int,
2317 elfcpp::Elf_types<32>::Elf_Addr,
2318 unsigned char* view,
2319 section_size_type view_size)
2320 {
2321 // leal foo(%reg), %eax; call ___tls_get_addr
2322 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2323
2324 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2325 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2326
2327 // FIXME: Does this test really always pass?
2328 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2329 view[-2] == 0x8d && view[-1] == 0x83);
2330
2331 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2332
2333 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2334
2335 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2336 // We can skip it.
2337 this->skip_call_tls_get_addr_ = true;
2338 }
2339
2340 // Do a relocation in which we convert a TLS Initial-Exec to a
2341 // Local-Exec.
2342
2343 inline void
2344 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2345 size_t relnum,
2346 Output_segment* tls_segment,
2347 const elfcpp::Rel<32, false>& rel,
2348 unsigned int r_type,
2349 elfcpp::Elf_types<32>::Elf_Addr value,
2350 unsigned char* view,
2351 section_size_type view_size)
2352 {
2353 // We have to actually change the instructions, which means that we
2354 // need to examine the opcodes to figure out which instruction we
2355 // are looking at.
2356 if (r_type == elfcpp::R_386_TLS_IE)
2357 {
2358 // movl %gs:XX,%eax ==> movl $YY,%eax
2359 // movl %gs:XX,%reg ==> movl $YY,%reg
2360 // addl %gs:XX,%reg ==> addl $YY,%reg
2361 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2362 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2363
2364 unsigned char op1 = view[-1];
2365 if (op1 == 0xa1)
2366 {
2367 // movl XX,%eax ==> movl $YY,%eax
2368 view[-1] = 0xb8;
2369 }
2370 else
2371 {
2372 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2373
2374 unsigned char op2 = view[-2];
2375 if (op2 == 0x8b)
2376 {
2377 // movl XX,%reg ==> movl $YY,%reg
2378 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2379 (op1 & 0xc7) == 0x05);
2380 view[-2] = 0xc7;
2381 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2382 }
2383 else if (op2 == 0x03)
2384 {
2385 // addl XX,%reg ==> addl $YY,%reg
2386 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2387 (op1 & 0xc7) == 0x05);
2388 view[-2] = 0x81;
2389 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2390 }
2391 else
2392 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2393 }
2394 }
2395 else
2396 {
2397 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2398 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2399 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2400 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2401 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2402
2403 unsigned char op1 = view[-1];
2404 unsigned char op2 = view[-2];
2405 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2406 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2407 if (op2 == 0x8b)
2408 {
2409 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2410 view[-2] = 0xc7;
2411 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2412 }
2413 else if (op2 == 0x2b)
2414 {
2415 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2416 view[-2] = 0x81;
2417 view[-1] = 0xe8 | ((op1 >> 3) & 7);
2418 }
2419 else if (op2 == 0x03)
2420 {
2421 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2422 view[-2] = 0x81;
2423 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2424 }
2425 else
2426 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2427 }
2428
2429 value = tls_segment->memsz() - value;
2430 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2431 value = - value;
2432
2433 Relocate_functions<32, false>::rel32(view, value);
2434 }
2435
2436 // Relocate section data.
2437
2438 void
2439 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2440 unsigned int sh_type,
2441 const unsigned char* prelocs,
2442 size_t reloc_count,
2443 Output_section* output_section,
2444 bool needs_special_offset_handling,
2445 unsigned char* view,
2446 elfcpp::Elf_types<32>::Elf_Addr address,
2447 section_size_type view_size,
2448 const Reloc_symbol_changes* reloc_symbol_changes)
2449 {
2450 gold_assert(sh_type == elfcpp::SHT_REL);
2451
2452 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2453 Target_i386::Relocate>(
2454 relinfo,
2455 this,
2456 prelocs,
2457 reloc_count,
2458 output_section,
2459 needs_special_offset_handling,
2460 view,
2461 address,
2462 view_size,
2463 reloc_symbol_changes);
2464 }
2465
2466 // Return the size of a relocation while scanning during a relocatable
2467 // link.
2468
2469 unsigned int
2470 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2471 unsigned int r_type,
2472 Relobj* object)
2473 {
2474 switch (r_type)
2475 {
2476 case elfcpp::R_386_NONE:
2477 case elfcpp::R_386_GNU_VTINHERIT:
2478 case elfcpp::R_386_GNU_VTENTRY:
2479 case elfcpp::R_386_TLS_GD: // Global-dynamic
2480 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2481 case elfcpp::R_386_TLS_DESC_CALL:
2482 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2483 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2484 case elfcpp::R_386_TLS_IE: // Initial-exec
2485 case elfcpp::R_386_TLS_IE_32:
2486 case elfcpp::R_386_TLS_GOTIE:
2487 case elfcpp::R_386_TLS_LE: // Local-exec
2488 case elfcpp::R_386_TLS_LE_32:
2489 return 0;
2490
2491 case elfcpp::R_386_32:
2492 case elfcpp::R_386_PC32:
2493 case elfcpp::R_386_GOT32:
2494 case elfcpp::R_386_PLT32:
2495 case elfcpp::R_386_GOTOFF:
2496 case elfcpp::R_386_GOTPC:
2497 return 4;
2498
2499 case elfcpp::R_386_16:
2500 case elfcpp::R_386_PC16:
2501 return 2;
2502
2503 case elfcpp::R_386_8:
2504 case elfcpp::R_386_PC8:
2505 return 1;
2506
2507 // These are relocations which should only be seen by the
2508 // dynamic linker, and should never be seen here.
2509 case elfcpp::R_386_COPY:
2510 case elfcpp::R_386_GLOB_DAT:
2511 case elfcpp::R_386_JUMP_SLOT:
2512 case elfcpp::R_386_RELATIVE:
2513 case elfcpp::R_386_TLS_TPOFF:
2514 case elfcpp::R_386_TLS_DTPMOD32:
2515 case elfcpp::R_386_TLS_DTPOFF32:
2516 case elfcpp::R_386_TLS_TPOFF32:
2517 case elfcpp::R_386_TLS_DESC:
2518 object->error(_("unexpected reloc %u in object file"), r_type);
2519 return 0;
2520
2521 case elfcpp::R_386_32PLT:
2522 case elfcpp::R_386_TLS_GD_32:
2523 case elfcpp::R_386_TLS_GD_PUSH:
2524 case elfcpp::R_386_TLS_GD_CALL:
2525 case elfcpp::R_386_TLS_GD_POP:
2526 case elfcpp::R_386_TLS_LDM_32:
2527 case elfcpp::R_386_TLS_LDM_PUSH:
2528 case elfcpp::R_386_TLS_LDM_CALL:
2529 case elfcpp::R_386_TLS_LDM_POP:
2530 case elfcpp::R_386_USED_BY_INTEL_200:
2531 default:
2532 object->error(_("unsupported reloc %u in object file"), r_type);
2533 return 0;
2534 }
2535 }
2536
2537 // Scan the relocs during a relocatable link.
2538
2539 void
2540 Target_i386::scan_relocatable_relocs(const General_options& options,
2541 Symbol_table* symtab,
2542 Layout* layout,
2543 Sized_relobj<32, false>* object,
2544 unsigned int data_shndx,
2545 unsigned int sh_type,
2546 const unsigned char* prelocs,
2547 size_t reloc_count,
2548 Output_section* output_section,
2549 bool needs_special_offset_handling,
2550 size_t local_symbol_count,
2551 const unsigned char* plocal_symbols,
2552 Relocatable_relocs* rr)
2553 {
2554 gold_assert(sh_type == elfcpp::SHT_REL);
2555
2556 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2557 Relocatable_size_for_reloc> Scan_relocatable_relocs;
2558
2559 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2560 Scan_relocatable_relocs>(
2561 options,
2562 symtab,
2563 layout,
2564 object,
2565 data_shndx,
2566 prelocs,
2567 reloc_count,
2568 output_section,
2569 needs_special_offset_handling,
2570 local_symbol_count,
2571 plocal_symbols,
2572 rr);
2573 }
2574
2575 // Relocate a section during a relocatable link.
2576
2577 void
2578 Target_i386::relocate_for_relocatable(
2579 const Relocate_info<32, false>* relinfo,
2580 unsigned int sh_type,
2581 const unsigned char* prelocs,
2582 size_t reloc_count,
2583 Output_section* output_section,
2584 off_t offset_in_output_section,
2585 const Relocatable_relocs* rr,
2586 unsigned char* view,
2587 elfcpp::Elf_types<32>::Elf_Addr view_address,
2588 section_size_type view_size,
2589 unsigned char* reloc_view,
2590 section_size_type reloc_view_size)
2591 {
2592 gold_assert(sh_type == elfcpp::SHT_REL);
2593
2594 gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2595 relinfo,
2596 prelocs,
2597 reloc_count,
2598 output_section,
2599 offset_in_output_section,
2600 rr,
2601 view,
2602 view_address,
2603 view_size,
2604 reloc_view,
2605 reloc_view_size);
2606 }
2607
2608 // Return the value to use for a dynamic which requires special
2609 // treatment. This is how we support equality comparisons of function
2610 // pointers across shared library boundaries, as described in the
2611 // processor specific ABI supplement.
2612
2613 uint64_t
2614 Target_i386::do_dynsym_value(const Symbol* gsym) const
2615 {
2616 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2617 return this->plt_section()->address() + gsym->plt_offset();
2618 }
2619
2620 // Return a string used to fill a code section with nops to take up
2621 // the specified length.
2622
2623 std::string
2624 Target_i386::do_code_fill(section_size_type length) const
2625 {
2626 if (length >= 16)
2627 {
2628 // Build a jmp instruction to skip over the bytes.
2629 unsigned char jmp[5];
2630 jmp[0] = 0xe9;
2631 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2632 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2633 + std::string(length - 5, '\0'));
2634 }
2635
2636 // Nop sequences of various lengths.
2637 const char nop1[1] = { 0x90 }; // nop
2638 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2639 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
2640 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
2641 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
2642 0x00 }; // leal 0(%esi,1),%esi
2643 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2644 0x00, 0x00 };
2645 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2646 0x00, 0x00, 0x00 };
2647 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
2648 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2649 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
2650 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
2651 0x00 };
2652 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2653 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2654 0x00, 0x00 };
2655 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2656 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2657 0x00, 0x00, 0x00 };
2658 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2659 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2660 0x00, 0x00, 0x00, 0x00 };
2661 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2662 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2663 0x27, 0x00, 0x00, 0x00,
2664 0x00 };
2665 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2666 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2667 0xbc, 0x27, 0x00, 0x00,
2668 0x00, 0x00 };
2669 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2670 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2671 0x90, 0x90, 0x90, 0x90,
2672 0x90, 0x90, 0x90 };
2673
2674 const char* nops[16] = {
2675 NULL,
2676 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2677 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2678 };
2679
2680 return std::string(nops[length], length);
2681 }
2682
2683 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2684 // compiled with -fstack-split. The function calls non-stack-split
2685 // code. We have to change the function so that it always ensures
2686 // that it has enough stack space to run some random function.
2687
2688 void
2689 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2690 section_offset_type fnoffset,
2691 section_size_type fnsize,
2692 unsigned char* view,
2693 section_size_type view_size,
2694 std::string* from,
2695 std::string* to) const
2696 {
2697 // The function starts with a comparison of the stack pointer and a
2698 // field in the TCB. This is followed by a jump.
2699
2700 // cmp %gs:NN,%esp
2701 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2702 && fnsize > 7)
2703 {
2704 // We will call __morestack if the carry flag is set after this
2705 // comparison. We turn the comparison into an stc instruction
2706 // and some nops.
2707 view[fnoffset] = '\xf9';
2708 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2709 }
2710 // lea NN(%esp),%ecx
2711 else if (this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2712 && fnsize > 7)
2713 {
2714 // This is loading an offset from the stack pointer for a
2715 // comparison. The offset is negative, so we decrease the
2716 // offset by the amount of space we need for the stack. This
2717 // means we will avoid calling __morestack if there happens to
2718 // be plenty of space on the stack already.
2719 unsigned char* pval = view + fnoffset + 3;
2720 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2721 val -= parameters->options().split_stack_adjust_size();
2722 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2723 }
2724 else
2725 {
2726 if (!object->has_no_split_stack())
2727 object->error(_("failed to match split-stack sequence at "
2728 "section %u offset %0zx"),
2729 shndx, fnoffset);
2730 return;
2731 }
2732
2733 // We have to change the function so that it calls
2734 // __morestack_non_split instead of __morestack. The former will
2735 // allocate additional stack space.
2736 *from = "__morestack";
2737 *to = "__morestack_non_split";
2738 }
2739
2740 // The selector for i386 object files.
2741
2742 class Target_selector_i386 : public Target_selector_freebsd
2743 {
2744 public:
2745 Target_selector_i386()
2746 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2747 "elf32-i386", "elf32-i386-freebsd")
2748 { }
2749
2750 Target*
2751 do_instantiate_target()
2752 { return new Target_i386(); }
2753 };
2754
2755 Target_selector_i386 target_selector_i386;
2756
2757 } // End anonymous namespace.
This page took 0.116535 seconds and 5 git commands to generate.