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