PR binutils/11742
[binutils.git] / gold / i386.cc
blobb4040c198cd769c6aa7ed04a2604e99418400ce2
1 // i386.cc -- i386 target support for gold.
3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
23 #include "gold.h"
25 #include <cstring>
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"
43 namespace
46 using namespace gold;
48 class Output_data_plt_i386;
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
55 class Target_i386 : public Target_freebsd<32, false>
57 public:
58 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
60 Target_i386()
61 : Target_freebsd<32, false>(&i386_info),
62 got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL),
63 global_offset_table_(NULL), rel_dyn_(NULL),
64 copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
65 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
66 { }
68 inline bool
69 can_check_for_function_pointers() const
70 { return true; }
72 // Process the relocations to determine unreferenced sections for
73 // garbage collection.
74 void
75 gc_process_relocs(Symbol_table* symtab,
76 Layout* layout,
77 Sized_relobj<32, false>* object,
78 unsigned int data_shndx,
79 unsigned int sh_type,
80 const unsigned char* prelocs,
81 size_t reloc_count,
82 Output_section* output_section,
83 bool needs_special_offset_handling,
84 size_t local_symbol_count,
85 const unsigned char* plocal_symbols);
87 // Scan the relocations to look for symbol adjustments.
88 void
89 scan_relocs(Symbol_table* symtab,
90 Layout* layout,
91 Sized_relobj<32, false>* object,
92 unsigned int data_shndx,
93 unsigned int sh_type,
94 const unsigned char* prelocs,
95 size_t reloc_count,
96 Output_section* output_section,
97 bool needs_special_offset_handling,
98 size_t local_symbol_count,
99 const unsigned char* plocal_symbols);
101 // Finalize the sections.
102 void
103 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
105 // Return the value to use for a dynamic which requires special
106 // treatment.
107 uint64_t
108 do_dynsym_value(const Symbol*) const;
110 // Relocate a section.
111 void
112 relocate_section(const Relocate_info<32, false>*,
113 unsigned int sh_type,
114 const unsigned char* prelocs,
115 size_t reloc_count,
116 Output_section* output_section,
117 bool needs_special_offset_handling,
118 unsigned char* view,
119 elfcpp::Elf_types<32>::Elf_Addr view_address,
120 section_size_type view_size,
121 const Reloc_symbol_changes*);
123 // Scan the relocs during a relocatable link.
124 void
125 scan_relocatable_relocs(Symbol_table* symtab,
126 Layout* layout,
127 Sized_relobj<32, false>* object,
128 unsigned int data_shndx,
129 unsigned int sh_type,
130 const unsigned char* prelocs,
131 size_t reloc_count,
132 Output_section* output_section,
133 bool needs_special_offset_handling,
134 size_t local_symbol_count,
135 const unsigned char* plocal_symbols,
136 Relocatable_relocs*);
138 // Relocate a section during a relocatable link.
139 void
140 relocate_for_relocatable(const Relocate_info<32, false>*,
141 unsigned int sh_type,
142 const unsigned char* prelocs,
143 size_t reloc_count,
144 Output_section* output_section,
145 off_t offset_in_output_section,
146 const Relocatable_relocs*,
147 unsigned char* view,
148 elfcpp::Elf_types<32>::Elf_Addr view_address,
149 section_size_type view_size,
150 unsigned char* reloc_view,
151 section_size_type reloc_view_size);
153 // Return a string used to fill a code section with nops.
154 std::string
155 do_code_fill(section_size_type length) const;
157 // Return whether SYM is defined by the ABI.
158 bool
159 do_is_defined_by_abi(const Symbol* sym) const
160 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
162 // Return whether a symbol name implies a local label. The UnixWare
163 // 2.1 cc generates temporary symbols that start with .X, so we
164 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
165 // If so, we should move the .X recognition into
166 // Target::do_is_local_label_name.
167 bool
168 do_is_local_label_name(const char* name) const
170 if (name[0] == '.' && name[1] == 'X')
171 return true;
172 return Target::do_is_local_label_name(name);
175 // Return whether SYM is call to a non-split function.
176 bool
177 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
179 // Adjust -fstack-split code which calls non-stack-split code.
180 void
181 do_calls_non_split(Relobj* object, unsigned int shndx,
182 section_offset_type fnoffset, section_size_type fnsize,
183 unsigned char* view, section_size_type view_size,
184 std::string* from, std::string* to) const;
186 // Return the size of the GOT section.
187 section_size_type
188 got_size()
190 gold_assert(this->got_ != NULL);
191 return this->got_->data_size();
194 private:
195 // The class which scans relocations.
196 struct Scan
198 inline void
199 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
200 Sized_relobj<32, false>* object,
201 unsigned int data_shndx,
202 Output_section* output_section,
203 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
204 const elfcpp::Sym<32, false>& lsym);
206 inline void
207 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
208 Sized_relobj<32, false>* object,
209 unsigned int data_shndx,
210 Output_section* output_section,
211 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
212 Symbol* gsym);
214 inline bool
215 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
216 Target_i386* target,
217 Sized_relobj<32, false>* object,
218 unsigned int data_shndx,
219 Output_section* output_section,
220 const elfcpp::Rel<32, false>& reloc,
221 unsigned int r_type,
222 const elfcpp::Sym<32, false>& lsym);
224 inline bool
225 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
226 Target_i386* target,
227 Sized_relobj<32, false>* object,
228 unsigned int data_shndx,
229 Output_section* output_section,
230 const elfcpp::Rel<32, false>& reloc,
231 unsigned int r_type,
232 Symbol* gsym);
234 inline bool
235 possible_function_pointer_reloc(unsigned int r_type);
237 static void
238 unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
240 static void
241 unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
242 Symbol*);
245 // The class which implements relocation.
246 class Relocate
248 public:
249 Relocate()
250 : skip_call_tls_get_addr_(false),
251 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
254 ~Relocate()
256 if (this->skip_call_tls_get_addr_)
258 // FIXME: This needs to specify the location somehow.
259 gold_error(_("missing expected TLS relocation"));
263 // Return whether the static relocation needs to be applied.
264 inline bool
265 should_apply_static_reloc(const Sized_symbol<32>* gsym,
266 int ref_flags,
267 bool is_32bit,
268 Output_section* output_section);
270 // Do a relocation. Return false if the caller should not issue
271 // any warnings about this relocation.
272 inline bool
273 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
274 size_t relnum, const elfcpp::Rel<32, false>&,
275 unsigned int r_type, const Sized_symbol<32>*,
276 const Symbol_value<32>*,
277 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
278 section_size_type);
280 private:
281 // Do a TLS relocation.
282 inline void
283 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
284 size_t relnum, const elfcpp::Rel<32, false>&,
285 unsigned int r_type, const Sized_symbol<32>*,
286 const Symbol_value<32>*,
287 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
288 section_size_type);
290 // Do a TLS General-Dynamic to Initial-Exec transition.
291 inline void
292 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
293 Output_segment* tls_segment,
294 const elfcpp::Rel<32, false>&, unsigned int r_type,
295 elfcpp::Elf_types<32>::Elf_Addr value,
296 unsigned char* view,
297 section_size_type view_size);
299 // Do a TLS General-Dynamic to Local-Exec transition.
300 inline void
301 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
302 Output_segment* tls_segment,
303 const elfcpp::Rel<32, false>&, unsigned int r_type,
304 elfcpp::Elf_types<32>::Elf_Addr value,
305 unsigned char* view,
306 section_size_type view_size);
308 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
309 // transition.
310 inline void
311 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
312 Output_segment* tls_segment,
313 const elfcpp::Rel<32, false>&, unsigned int r_type,
314 elfcpp::Elf_types<32>::Elf_Addr value,
315 unsigned char* view,
316 section_size_type view_size);
318 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
319 // transition.
320 inline void
321 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
322 Output_segment* tls_segment,
323 const elfcpp::Rel<32, false>&, unsigned int r_type,
324 elfcpp::Elf_types<32>::Elf_Addr value,
325 unsigned char* view,
326 section_size_type view_size);
328 // Do a TLS Local-Dynamic to Local-Exec transition.
329 inline void
330 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
331 Output_segment* tls_segment,
332 const elfcpp::Rel<32, false>&, unsigned int r_type,
333 elfcpp::Elf_types<32>::Elf_Addr value,
334 unsigned char* view,
335 section_size_type view_size);
337 // Do a TLS Initial-Exec to Local-Exec transition.
338 static inline void
339 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
340 Output_segment* tls_segment,
341 const elfcpp::Rel<32, false>&, unsigned int r_type,
342 elfcpp::Elf_types<32>::Elf_Addr value,
343 unsigned char* view,
344 section_size_type view_size);
346 // We need to keep track of which type of local dynamic relocation
347 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
348 enum Local_dynamic_type
350 LOCAL_DYNAMIC_NONE,
351 LOCAL_DYNAMIC_SUN,
352 LOCAL_DYNAMIC_GNU
355 // This is set if we should skip the next reloc, which should be a
356 // PLT32 reloc against ___tls_get_addr.
357 bool skip_call_tls_get_addr_;
358 // The type of local dynamic relocation we have seen in the section
359 // being relocated, if any.
360 Local_dynamic_type local_dynamic_type_;
363 // A class which returns the size required for a relocation type,
364 // used while scanning relocs during a relocatable link.
365 class Relocatable_size_for_reloc
367 public:
368 unsigned int
369 get_size_for_reloc(unsigned int, Relobj*);
372 // Adjust TLS relocation type based on the options and whether this
373 // is a local symbol.
374 static tls::Tls_optimization
375 optimize_tls_reloc(bool is_final, int r_type);
377 // Get the GOT section, creating it if necessary.
378 Output_data_got<32, false>*
379 got_section(Symbol_table*, Layout*);
381 // Get the GOT PLT section.
382 Output_data_space*
383 got_plt_section() const
385 gold_assert(this->got_plt_ != NULL);
386 return this->got_plt_;
389 // Get the GOT section for TLSDESC entries.
390 Output_data_got<32, false>*
391 got_tlsdesc_section() const
393 gold_assert(this->got_tlsdesc_ != NULL);
394 return this->got_tlsdesc_;
397 // Create a PLT entry for a global symbol.
398 void
399 make_plt_entry(Symbol_table*, Layout*, Symbol*);
401 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
402 void
403 define_tls_base_symbol(Symbol_table*, Layout*);
405 // Create a GOT entry for the TLS module index.
406 unsigned int
407 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
408 Sized_relobj<32, false>* object);
410 // Get the PLT section.
411 Output_data_plt_i386*
412 plt_section() const
414 gold_assert(this->plt_ != NULL);
415 return this->plt_;
418 // Get the dynamic reloc section, creating it if necessary.
419 Reloc_section*
420 rel_dyn_section(Layout*);
422 // Get the section to use for TLS_DESC relocations.
423 Reloc_section*
424 rel_tls_desc_section(Layout*) const;
426 // Add a potential copy relocation.
427 void
428 copy_reloc(Symbol_table* symtab, Layout* layout,
429 Sized_relobj<32, false>* object,
430 unsigned int shndx, Output_section* output_section,
431 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
433 this->copy_relocs_.copy_reloc(symtab, layout,
434 symtab->get_sized_symbol<32>(sym),
435 object, shndx, output_section, reloc,
436 this->rel_dyn_section(layout));
439 // Information about this specific target which we pass to the
440 // general Target structure.
441 static const Target::Target_info i386_info;
443 // The types of GOT entries needed for this platform.
444 enum Got_type
446 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
447 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
448 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
449 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
450 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
453 // The GOT section.
454 Output_data_got<32, false>* got_;
455 // The PLT section.
456 Output_data_plt_i386* plt_;
457 // The GOT PLT section.
458 Output_data_space* got_plt_;
459 // The GOT section for TLSDESC relocations.
460 Output_data_got<32, false>* got_tlsdesc_;
461 // The _GLOBAL_OFFSET_TABLE_ symbol.
462 Symbol* global_offset_table_;
463 // The dynamic reloc section.
464 Reloc_section* rel_dyn_;
465 // Relocs saved to avoid a COPY reloc.
466 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
467 // Space for variables copied with a COPY reloc.
468 Output_data_space* dynbss_;
469 // Offset of the GOT entry for the TLS module index.
470 unsigned int got_mod_index_offset_;
471 // True if the _TLS_MODULE_BASE_ symbol has been defined.
472 bool tls_base_symbol_defined_;
475 const Target::Target_info Target_i386::i386_info =
477 32, // size
478 false, // is_big_endian
479 elfcpp::EM_386, // machine_code
480 false, // has_make_symbol
481 false, // has_resolve
482 true, // has_code_fill
483 true, // is_default_stack_executable
484 '\0', // wrap_char
485 "/usr/lib/libc.so.1", // dynamic_linker
486 0x08048000, // default_text_segment_address
487 0x1000, // abi_pagesize (overridable by -z max-page-size)
488 0x1000, // common_pagesize (overridable by -z common-page-size)
489 elfcpp::SHN_UNDEF, // small_common_shndx
490 elfcpp::SHN_UNDEF, // large_common_shndx
491 0, // small_common_section_flags
492 0, // large_common_section_flags
493 NULL, // attributes_section
494 NULL // attributes_vendor
497 // Get the GOT section, creating it if necessary.
499 Output_data_got<32, false>*
500 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
502 if (this->got_ == NULL)
504 gold_assert(symtab != NULL && layout != NULL);
506 this->got_ = new Output_data_got<32, false>();
508 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
509 (elfcpp::SHF_ALLOC
510 | elfcpp::SHF_WRITE),
511 this->got_, ORDER_RELRO_LAST, true);
513 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
514 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
515 (elfcpp::SHF_ALLOC
516 | elfcpp::SHF_WRITE),
517 this->got_plt_, ORDER_NON_RELRO_FIRST,
518 false);
520 // The first three entries are reserved.
521 this->got_plt_->set_current_data_size(3 * 4);
523 // Those bytes can go into the relro segment.
524 layout->increase_relro(3 * 4);
526 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
527 this->global_offset_table_ =
528 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
529 Symbol_table::PREDEFINED,
530 this->got_plt_,
531 0, 0, elfcpp::STT_OBJECT,
532 elfcpp::STB_LOCAL,
533 elfcpp::STV_HIDDEN, 0,
534 false, false);
536 // If there are any TLSDESC relocations, they get GOT entries in
537 // .got.plt after the jump slot entries.
538 this->got_tlsdesc_ = new Output_data_got<32, false>();
539 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
540 (elfcpp::SHF_ALLOC
541 | elfcpp::SHF_WRITE),
542 this->got_tlsdesc_,
543 ORDER_NON_RELRO_FIRST, false);
546 return this->got_;
549 // Get the dynamic reloc section, creating it if necessary.
551 Target_i386::Reloc_section*
552 Target_i386::rel_dyn_section(Layout* layout)
554 if (this->rel_dyn_ == NULL)
556 gold_assert(layout != NULL);
557 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
558 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
559 elfcpp::SHF_ALLOC, this->rel_dyn_,
560 ORDER_DYNAMIC_RELOCS, false);
562 return this->rel_dyn_;
565 // A class to handle the PLT data.
567 class Output_data_plt_i386 : public Output_section_data
569 public:
570 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
572 Output_data_plt_i386(Layout*, Output_data_space*);
574 // Add an entry to the PLT.
575 void
576 add_entry(Symbol* gsym);
578 // Return the .rel.plt section data.
579 const Reloc_section*
580 rel_plt() const
581 { return this->rel_; }
583 // Return where the TLS_DESC relocations should go.
584 Reloc_section*
585 rel_tls_desc(Layout*);
587 protected:
588 void
589 do_adjust_output_section(Output_section* os);
591 // Write to a map file.
592 void
593 do_print_to_mapfile(Mapfile* mapfile) const
594 { mapfile->print_output_data(this, _("** PLT")); }
596 private:
597 // The size of an entry in the PLT.
598 static const int plt_entry_size = 16;
600 // The first entry in the PLT for an executable.
601 static unsigned char exec_first_plt_entry[plt_entry_size];
603 // The first entry in the PLT for a shared object.
604 static unsigned char dyn_first_plt_entry[plt_entry_size];
606 // Other entries in the PLT for an executable.
607 static unsigned char exec_plt_entry[plt_entry_size];
609 // Other entries in the PLT for a shared object.
610 static unsigned char dyn_plt_entry[plt_entry_size];
612 // Set the final size.
613 void
614 set_final_data_size()
615 { this->set_data_size((this->count_ + 1) * plt_entry_size); }
617 // Write out the PLT data.
618 void
619 do_write(Output_file*);
621 // The reloc section.
622 Reloc_section* rel_;
623 // The TLS_DESC relocations, if necessary. These must follow the
624 // regular PLT relocs.
625 Reloc_section* tls_desc_rel_;
626 // The .got.plt section.
627 Output_data_space* got_plt_;
628 // The number of PLT entries.
629 unsigned int count_;
632 // Create the PLT section. The ordinary .got section is an argument,
633 // since we need to refer to the start. We also create our own .got
634 // section just for PLT entries.
636 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
637 Output_data_space* got_plt)
638 : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0)
640 this->rel_ = new Reloc_section(false);
641 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
642 elfcpp::SHF_ALLOC, this->rel_,
643 ORDER_DYNAMIC_PLT_RELOCS, false);
646 void
647 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
649 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
650 // linker, and so do we.
651 os->set_entsize(4);
654 // Add an entry to the PLT.
656 void
657 Output_data_plt_i386::add_entry(Symbol* gsym)
659 gold_assert(!gsym->has_plt_offset());
661 // Note that when setting the PLT offset we skip the initial
662 // reserved PLT entry.
663 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
665 ++this->count_;
667 section_offset_type got_offset = this->got_plt_->current_data_size();
669 // Every PLT entry needs a GOT entry which points back to the PLT
670 // entry (this will be changed by the dynamic linker, normally
671 // lazily when the function is called).
672 this->got_plt_->set_current_data_size(got_offset + 4);
674 // Every PLT entry needs a reloc.
675 gsym->set_needs_dynsym_entry();
676 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
677 got_offset);
679 // Note that we don't need to save the symbol. The contents of the
680 // PLT are independent of which symbols are used. The symbols only
681 // appear in the relocations.
684 // Return where the TLS_DESC relocations should go, creating it if
685 // necessary. These follow the JUMP_SLOT relocations.
687 Output_data_plt_i386::Reloc_section*
688 Output_data_plt_i386::rel_tls_desc(Layout* layout)
690 if (this->tls_desc_rel_ == NULL)
692 this->tls_desc_rel_ = new Reloc_section(false);
693 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
694 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
695 ORDER_DYNAMIC_PLT_RELOCS, false);
696 gold_assert(this->tls_desc_rel_->output_section() ==
697 this->rel_->output_section());
699 return this->tls_desc_rel_;
702 // The first entry in the PLT for an executable.
704 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
706 0xff, 0x35, // pushl contents of memory address
707 0, 0, 0, 0, // replaced with address of .got + 4
708 0xff, 0x25, // jmp indirect
709 0, 0, 0, 0, // replaced with address of .got + 8
710 0, 0, 0, 0 // unused
713 // The first entry in the PLT for a shared object.
715 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
717 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
718 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
719 0, 0, 0, 0 // unused
722 // Subsequent entries in the PLT for an executable.
724 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
726 0xff, 0x25, // jmp indirect
727 0, 0, 0, 0, // replaced with address of symbol in .got
728 0x68, // pushl immediate
729 0, 0, 0, 0, // replaced with offset into relocation table
730 0xe9, // jmp relative
731 0, 0, 0, 0 // replaced with offset to start of .plt
734 // Subsequent entries in the PLT for a shared object.
736 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
738 0xff, 0xa3, // jmp *offset(%ebx)
739 0, 0, 0, 0, // replaced with offset of symbol in .got
740 0x68, // pushl immediate
741 0, 0, 0, 0, // replaced with offset into relocation table
742 0xe9, // jmp relative
743 0, 0, 0, 0 // replaced with offset to start of .plt
746 // Write out the PLT. This uses the hand-coded instructions above,
747 // and adjusts them as needed. This is all specified by the i386 ELF
748 // Processor Supplement.
750 void
751 Output_data_plt_i386::do_write(Output_file* of)
753 const off_t offset = this->offset();
754 const section_size_type oview_size =
755 convert_to_section_size_type(this->data_size());
756 unsigned char* const oview = of->get_output_view(offset, oview_size);
758 const off_t got_file_offset = this->got_plt_->offset();
759 const section_size_type got_size =
760 convert_to_section_size_type(this->got_plt_->data_size());
761 unsigned char* const got_view = of->get_output_view(got_file_offset,
762 got_size);
764 unsigned char* pov = oview;
766 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
767 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
769 if (parameters->options().output_is_position_independent())
770 memcpy(pov, dyn_first_plt_entry, plt_entry_size);
771 else
773 memcpy(pov, exec_first_plt_entry, plt_entry_size);
774 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
775 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
777 pov += plt_entry_size;
779 unsigned char* got_pov = got_view;
781 memset(got_pov, 0, 12);
782 got_pov += 12;
784 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
786 unsigned int plt_offset = plt_entry_size;
787 unsigned int plt_rel_offset = 0;
788 unsigned int got_offset = 12;
789 const unsigned int count = this->count_;
790 for (unsigned int i = 0;
791 i < count;
792 ++i,
793 pov += plt_entry_size,
794 got_pov += 4,
795 plt_offset += plt_entry_size,
796 plt_rel_offset += rel_size,
797 got_offset += 4)
799 // Set and adjust the PLT entry itself.
801 if (parameters->options().output_is_position_independent())
803 memcpy(pov, dyn_plt_entry, plt_entry_size);
804 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
806 else
808 memcpy(pov, exec_plt_entry, plt_entry_size);
809 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
810 (got_address
811 + got_offset));
814 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
815 elfcpp::Swap<32, false>::writeval(pov + 12,
816 - (plt_offset + plt_entry_size));
818 // Set the entry in the GOT.
819 elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
822 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
823 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
825 of->write_output_view(offset, oview_size, oview);
826 of->write_output_view(got_file_offset, got_size, got_view);
829 // Create a PLT entry for a global symbol.
831 void
832 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
834 if (gsym->has_plt_offset())
835 return;
837 if (this->plt_ == NULL)
839 // Create the GOT sections first.
840 this->got_section(symtab, layout);
842 this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
843 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
844 (elfcpp::SHF_ALLOC
845 | elfcpp::SHF_EXECINSTR),
846 this->plt_, ORDER_PLT, false);
849 this->plt_->add_entry(gsym);
852 // Get the section to use for TLS_DESC relocations.
854 Target_i386::Reloc_section*
855 Target_i386::rel_tls_desc_section(Layout* layout) const
857 return this->plt_section()->rel_tls_desc(layout);
860 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
862 void
863 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
865 if (this->tls_base_symbol_defined_)
866 return;
868 Output_segment* tls_segment = layout->tls_segment();
869 if (tls_segment != NULL)
871 bool is_exec = parameters->options().output_is_executable();
872 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
873 Symbol_table::PREDEFINED,
874 tls_segment, 0, 0,
875 elfcpp::STT_TLS,
876 elfcpp::STB_LOCAL,
877 elfcpp::STV_HIDDEN, 0,
878 (is_exec
879 ? Symbol::SEGMENT_END
880 : Symbol::SEGMENT_START),
881 true);
883 this->tls_base_symbol_defined_ = true;
886 // Create a GOT entry for the TLS module index.
888 unsigned int
889 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
890 Sized_relobj<32, false>* object)
892 if (this->got_mod_index_offset_ == -1U)
894 gold_assert(symtab != NULL && layout != NULL && object != NULL);
895 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
896 Output_data_got<32, false>* got = this->got_section(symtab, layout);
897 unsigned int got_offset = got->add_constant(0);
898 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
899 got_offset);
900 got->add_constant(0);
901 this->got_mod_index_offset_ = got_offset;
903 return this->got_mod_index_offset_;
906 // Optimize the TLS relocation type based on what we know about the
907 // symbol. IS_FINAL is true if the final address of this symbol is
908 // known at link time.
910 tls::Tls_optimization
911 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
913 // If we are generating a shared library, then we can't do anything
914 // in the linker.
915 if (parameters->options().shared())
916 return tls::TLSOPT_NONE;
918 switch (r_type)
920 case elfcpp::R_386_TLS_GD:
921 case elfcpp::R_386_TLS_GOTDESC:
922 case elfcpp::R_386_TLS_DESC_CALL:
923 // These are General-Dynamic which permits fully general TLS
924 // access. Since we know that we are generating an executable,
925 // we can convert this to Initial-Exec. If we also know that
926 // this is a local symbol, we can further switch to Local-Exec.
927 if (is_final)
928 return tls::TLSOPT_TO_LE;
929 return tls::TLSOPT_TO_IE;
931 case elfcpp::R_386_TLS_LDM:
932 // This is Local-Dynamic, which refers to a local symbol in the
933 // dynamic TLS block. Since we know that we generating an
934 // executable, we can switch to Local-Exec.
935 return tls::TLSOPT_TO_LE;
937 case elfcpp::R_386_TLS_LDO_32:
938 // Another type of Local-Dynamic relocation.
939 return tls::TLSOPT_TO_LE;
941 case elfcpp::R_386_TLS_IE:
942 case elfcpp::R_386_TLS_GOTIE:
943 case elfcpp::R_386_TLS_IE_32:
944 // These are Initial-Exec relocs which get the thread offset
945 // from the GOT. If we know that we are linking against the
946 // local symbol, we can switch to Local-Exec, which links the
947 // thread offset into the instruction.
948 if (is_final)
949 return tls::TLSOPT_TO_LE;
950 return tls::TLSOPT_NONE;
952 case elfcpp::R_386_TLS_LE:
953 case elfcpp::R_386_TLS_LE_32:
954 // When we already have Local-Exec, there is nothing further we
955 // can do.
956 return tls::TLSOPT_NONE;
958 default:
959 gold_unreachable();
963 // Report an unsupported relocation against a local symbol.
965 void
966 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
967 unsigned int r_type)
969 gold_error(_("%s: unsupported reloc %u against local symbol"),
970 object->name().c_str(), r_type);
973 // Scan a relocation for a local symbol.
975 inline void
976 Target_i386::Scan::local(Symbol_table* symtab,
977 Layout* layout,
978 Target_i386* target,
979 Sized_relobj<32, false>* object,
980 unsigned int data_shndx,
981 Output_section* output_section,
982 const elfcpp::Rel<32, false>& reloc,
983 unsigned int r_type,
984 const elfcpp::Sym<32, false>& lsym)
986 switch (r_type)
988 case elfcpp::R_386_NONE:
989 case elfcpp::R_386_GNU_VTINHERIT:
990 case elfcpp::R_386_GNU_VTENTRY:
991 break;
993 case elfcpp::R_386_32:
994 // If building a shared library (or a position-independent
995 // executable), we need to create a dynamic relocation for
996 // this location. The relocation applied at link time will
997 // apply the link-time value, so we flag the location with
998 // an R_386_RELATIVE relocation so the dynamic loader can
999 // relocate it easily.
1000 if (parameters->options().output_is_position_independent())
1002 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1003 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1004 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1005 output_section, data_shndx,
1006 reloc.get_r_offset());
1008 break;
1010 case elfcpp::R_386_16:
1011 case elfcpp::R_386_8:
1012 // If building a shared library (or a position-independent
1013 // executable), we need to create a dynamic relocation for
1014 // this location. Because the addend needs to remain in the
1015 // data section, we need to be careful not to apply this
1016 // relocation statically.
1017 if (parameters->options().output_is_position_independent())
1019 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1020 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1021 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1022 rel_dyn->add_local(object, r_sym, r_type, output_section,
1023 data_shndx, reloc.get_r_offset());
1024 else
1026 gold_assert(lsym.get_st_value() == 0);
1027 unsigned int shndx = lsym.get_st_shndx();
1028 bool is_ordinary;
1029 shndx = object->adjust_sym_shndx(r_sym, shndx,
1030 &is_ordinary);
1031 if (!is_ordinary)
1032 object->error(_("section symbol %u has bad shndx %u"),
1033 r_sym, shndx);
1034 else
1035 rel_dyn->add_local_section(object, shndx,
1036 r_type, output_section,
1037 data_shndx, reloc.get_r_offset());
1040 break;
1042 case elfcpp::R_386_PC32:
1043 case elfcpp::R_386_PC16:
1044 case elfcpp::R_386_PC8:
1045 break;
1047 case elfcpp::R_386_PLT32:
1048 // Since we know this is a local symbol, we can handle this as a
1049 // PC32 reloc.
1050 break;
1052 case elfcpp::R_386_GOTOFF:
1053 case elfcpp::R_386_GOTPC:
1054 // We need a GOT section.
1055 target->got_section(symtab, layout);
1056 break;
1058 case elfcpp::R_386_GOT32:
1060 // The symbol requires a GOT entry.
1061 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1062 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1063 if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1065 // If we are generating a shared object, we need to add a
1066 // dynamic RELATIVE relocation for this symbol's GOT entry.
1067 if (parameters->options().output_is_position_independent())
1069 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1070 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1071 rel_dyn->add_local_relative(
1072 object, r_sym, elfcpp::R_386_RELATIVE, got,
1073 object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
1077 break;
1079 // These are relocations which should only be seen by the
1080 // dynamic linker, and should never be seen here.
1081 case elfcpp::R_386_COPY:
1082 case elfcpp::R_386_GLOB_DAT:
1083 case elfcpp::R_386_JUMP_SLOT:
1084 case elfcpp::R_386_RELATIVE:
1085 case elfcpp::R_386_TLS_TPOFF:
1086 case elfcpp::R_386_TLS_DTPMOD32:
1087 case elfcpp::R_386_TLS_DTPOFF32:
1088 case elfcpp::R_386_TLS_TPOFF32:
1089 case elfcpp::R_386_TLS_DESC:
1090 gold_error(_("%s: unexpected reloc %u in object file"),
1091 object->name().c_str(), r_type);
1092 break;
1094 // These are initial TLS relocs, which are expected when
1095 // linking.
1096 case elfcpp::R_386_TLS_GD: // Global-dynamic
1097 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1098 case elfcpp::R_386_TLS_DESC_CALL:
1099 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1100 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1101 case elfcpp::R_386_TLS_IE: // Initial-exec
1102 case elfcpp::R_386_TLS_IE_32:
1103 case elfcpp::R_386_TLS_GOTIE:
1104 case elfcpp::R_386_TLS_LE: // Local-exec
1105 case elfcpp::R_386_TLS_LE_32:
1107 bool output_is_shared = parameters->options().shared();
1108 const tls::Tls_optimization optimized_type
1109 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1110 switch (r_type)
1112 case elfcpp::R_386_TLS_GD: // Global-dynamic
1113 if (optimized_type == tls::TLSOPT_NONE)
1115 // Create a pair of GOT entries for the module index and
1116 // dtv-relative offset.
1117 Output_data_got<32, false>* got
1118 = target->got_section(symtab, layout);
1119 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1120 unsigned int shndx = lsym.get_st_shndx();
1121 bool is_ordinary;
1122 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1123 if (!is_ordinary)
1124 object->error(_("local symbol %u has bad shndx %u"),
1125 r_sym, shndx);
1126 else
1127 got->add_local_pair_with_rel(object, r_sym, shndx,
1128 GOT_TYPE_TLS_PAIR,
1129 target->rel_dyn_section(layout),
1130 elfcpp::R_386_TLS_DTPMOD32, 0);
1132 else if (optimized_type != tls::TLSOPT_TO_LE)
1133 unsupported_reloc_local(object, r_type);
1134 break;
1136 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1137 target->define_tls_base_symbol(symtab, layout);
1138 if (optimized_type == tls::TLSOPT_NONE)
1140 // Create a double GOT entry with an R_386_TLS_DESC
1141 // reloc. The R_386_TLS_DESC reloc is resolved
1142 // lazily, so the GOT entry needs to be in an area in
1143 // .got.plt, not .got. Call got_section to make sure
1144 // the section has been created.
1145 target->got_section(symtab, layout);
1146 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1147 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1148 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1150 unsigned int got_offset = got->add_constant(0);
1151 // The local symbol value is stored in the second
1152 // GOT entry.
1153 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1154 // That set the GOT offset of the local symbol to
1155 // point to the second entry, but we want it to
1156 // point to the first.
1157 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1158 got_offset);
1159 Reloc_section* rt = target->rel_tls_desc_section(layout);
1160 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1163 else if (optimized_type != tls::TLSOPT_TO_LE)
1164 unsupported_reloc_local(object, r_type);
1165 break;
1167 case elfcpp::R_386_TLS_DESC_CALL:
1168 break;
1170 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1171 if (optimized_type == tls::TLSOPT_NONE)
1173 // Create a GOT entry for the module index.
1174 target->got_mod_index_entry(symtab, layout, object);
1176 else if (optimized_type != tls::TLSOPT_TO_LE)
1177 unsupported_reloc_local(object, r_type);
1178 break;
1180 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1181 break;
1183 case elfcpp::R_386_TLS_IE: // Initial-exec
1184 case elfcpp::R_386_TLS_IE_32:
1185 case elfcpp::R_386_TLS_GOTIE:
1186 layout->set_has_static_tls();
1187 if (optimized_type == tls::TLSOPT_NONE)
1189 // For the R_386_TLS_IE relocation, we need to create a
1190 // dynamic relocation when building a shared library.
1191 if (r_type == elfcpp::R_386_TLS_IE
1192 && parameters->options().shared())
1194 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1195 unsigned int r_sym
1196 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1197 rel_dyn->add_local_relative(object, r_sym,
1198 elfcpp::R_386_RELATIVE,
1199 output_section, data_shndx,
1200 reloc.get_r_offset());
1202 // Create a GOT entry for the tp-relative offset.
1203 Output_data_got<32, false>* got
1204 = target->got_section(symtab, layout);
1205 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1206 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1207 ? elfcpp::R_386_TLS_TPOFF32
1208 : elfcpp::R_386_TLS_TPOFF);
1209 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1210 ? GOT_TYPE_TLS_OFFSET
1211 : GOT_TYPE_TLS_NOFFSET);
1212 got->add_local_with_rel(object, r_sym, got_type,
1213 target->rel_dyn_section(layout),
1214 dyn_r_type);
1216 else if (optimized_type != tls::TLSOPT_TO_LE)
1217 unsupported_reloc_local(object, r_type);
1218 break;
1220 case elfcpp::R_386_TLS_LE: // Local-exec
1221 case elfcpp::R_386_TLS_LE_32:
1222 layout->set_has_static_tls();
1223 if (output_is_shared)
1225 // We need to create a dynamic relocation.
1226 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1227 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1228 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1229 ? elfcpp::R_386_TLS_TPOFF32
1230 : elfcpp::R_386_TLS_TPOFF);
1231 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1232 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1233 data_shndx, reloc.get_r_offset());
1235 break;
1237 default:
1238 gold_unreachable();
1241 break;
1243 case elfcpp::R_386_32PLT:
1244 case elfcpp::R_386_TLS_GD_32:
1245 case elfcpp::R_386_TLS_GD_PUSH:
1246 case elfcpp::R_386_TLS_GD_CALL:
1247 case elfcpp::R_386_TLS_GD_POP:
1248 case elfcpp::R_386_TLS_LDM_32:
1249 case elfcpp::R_386_TLS_LDM_PUSH:
1250 case elfcpp::R_386_TLS_LDM_CALL:
1251 case elfcpp::R_386_TLS_LDM_POP:
1252 case elfcpp::R_386_USED_BY_INTEL_200:
1253 default:
1254 unsupported_reloc_local(object, r_type);
1255 break;
1259 // Report an unsupported relocation against a global symbol.
1261 void
1262 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1263 unsigned int r_type,
1264 Symbol* gsym)
1266 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1267 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1270 inline bool
1271 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
1273 switch (r_type)
1275 case elfcpp::R_386_32:
1276 case elfcpp::R_386_16:
1277 case elfcpp::R_386_8:
1278 case elfcpp::R_386_GOTOFF:
1279 case elfcpp::R_386_GOT32:
1281 return true;
1283 default:
1284 return false;
1286 return false;
1289 inline bool
1290 Target_i386::Scan::local_reloc_may_be_function_pointer(
1291 Symbol_table* ,
1292 Layout* ,
1293 Target_i386* ,
1294 Sized_relobj<32, false>* ,
1295 unsigned int ,
1296 Output_section* ,
1297 const elfcpp::Rel<32, false>& ,
1298 unsigned int r_type,
1299 const elfcpp::Sym<32, false>&)
1301 return possible_function_pointer_reloc(r_type);
1304 inline bool
1305 Target_i386::Scan::global_reloc_may_be_function_pointer(
1306 Symbol_table* ,
1307 Layout* ,
1308 Target_i386* ,
1309 Sized_relobj<32, false>* ,
1310 unsigned int ,
1311 Output_section* ,
1312 const elfcpp::Rel<32, false>& ,
1313 unsigned int r_type,
1314 Symbol*)
1316 return possible_function_pointer_reloc(r_type);
1319 // Scan a relocation for a global symbol.
1321 inline void
1322 Target_i386::Scan::global(Symbol_table* symtab,
1323 Layout* layout,
1324 Target_i386* target,
1325 Sized_relobj<32, false>* object,
1326 unsigned int data_shndx,
1327 Output_section* output_section,
1328 const elfcpp::Rel<32, false>& reloc,
1329 unsigned int r_type,
1330 Symbol* gsym)
1332 switch (r_type)
1334 case elfcpp::R_386_NONE:
1335 case elfcpp::R_386_GNU_VTINHERIT:
1336 case elfcpp::R_386_GNU_VTENTRY:
1337 break;
1339 case elfcpp::R_386_32:
1340 case elfcpp::R_386_16:
1341 case elfcpp::R_386_8:
1343 // Make a PLT entry if necessary.
1344 if (gsym->needs_plt_entry())
1346 target->make_plt_entry(symtab, layout, gsym);
1347 // Since this is not a PC-relative relocation, we may be
1348 // taking the address of a function. In that case we need to
1349 // set the entry in the dynamic symbol table to the address of
1350 // the PLT entry.
1351 if (gsym->is_from_dynobj() && !parameters->options().shared())
1352 gsym->set_needs_dynsym_value();
1354 // Make a dynamic relocation if necessary.
1355 if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1357 if (gsym->may_need_copy_reloc())
1359 target->copy_reloc(symtab, layout, object,
1360 data_shndx, output_section, gsym, reloc);
1362 else if (r_type == elfcpp::R_386_32
1363 && gsym->can_use_relative_reloc(false))
1365 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1366 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1367 output_section, object,
1368 data_shndx, reloc.get_r_offset());
1370 else
1372 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1373 rel_dyn->add_global(gsym, r_type, output_section, object,
1374 data_shndx, reloc.get_r_offset());
1378 break;
1380 case elfcpp::R_386_PC32:
1381 case elfcpp::R_386_PC16:
1382 case elfcpp::R_386_PC8:
1384 // Make a PLT entry if necessary.
1385 if (gsym->needs_plt_entry())
1387 // These relocations are used for function calls only in
1388 // non-PIC code. For a 32-bit relocation in a shared library,
1389 // we'll need a text relocation anyway, so we can skip the
1390 // PLT entry and let the dynamic linker bind the call directly
1391 // to the target. For smaller relocations, we should use a
1392 // PLT entry to ensure that the call can reach.
1393 if (!parameters->options().shared()
1394 || r_type != elfcpp::R_386_PC32)
1395 target->make_plt_entry(symtab, layout, gsym);
1397 // Make a dynamic relocation if necessary.
1398 int flags = Symbol::NON_PIC_REF;
1399 if (gsym->is_func())
1400 flags |= Symbol::FUNCTION_CALL;
1401 if (gsym->needs_dynamic_reloc(flags))
1403 if (gsym->may_need_copy_reloc())
1405 target->copy_reloc(symtab, layout, object,
1406 data_shndx, output_section, gsym, reloc);
1408 else
1410 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1411 rel_dyn->add_global(gsym, r_type, output_section, object,
1412 data_shndx, reloc.get_r_offset());
1416 break;
1418 case elfcpp::R_386_GOT32:
1420 // The symbol requires a GOT entry.
1421 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1422 if (gsym->final_value_is_known())
1423 got->add_global(gsym, GOT_TYPE_STANDARD);
1424 else
1426 // If this symbol is not fully resolved, we need to add a
1427 // GOT entry with a dynamic relocation.
1428 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1429 if (gsym->is_from_dynobj()
1430 || gsym->is_undefined()
1431 || gsym->is_preemptible())
1432 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1433 rel_dyn, elfcpp::R_386_GLOB_DAT);
1434 else
1436 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1437 rel_dyn->add_global_relative(
1438 gsym, elfcpp::R_386_RELATIVE, got,
1439 gsym->got_offset(GOT_TYPE_STANDARD));
1443 break;
1445 case elfcpp::R_386_PLT32:
1446 // If the symbol is fully resolved, this is just a PC32 reloc.
1447 // Otherwise we need a PLT entry.
1448 if (gsym->final_value_is_known())
1449 break;
1450 // If building a shared library, we can also skip the PLT entry
1451 // if the symbol is defined in the output file and is protected
1452 // or hidden.
1453 if (gsym->is_defined()
1454 && !gsym->is_from_dynobj()
1455 && !gsym->is_preemptible())
1456 break;
1457 target->make_plt_entry(symtab, layout, gsym);
1458 break;
1460 case elfcpp::R_386_GOTOFF:
1461 case elfcpp::R_386_GOTPC:
1462 // We need a GOT section.
1463 target->got_section(symtab, layout);
1464 break;
1466 // These are relocations which should only be seen by the
1467 // dynamic linker, and should never be seen here.
1468 case elfcpp::R_386_COPY:
1469 case elfcpp::R_386_GLOB_DAT:
1470 case elfcpp::R_386_JUMP_SLOT:
1471 case elfcpp::R_386_RELATIVE:
1472 case elfcpp::R_386_TLS_TPOFF:
1473 case elfcpp::R_386_TLS_DTPMOD32:
1474 case elfcpp::R_386_TLS_DTPOFF32:
1475 case elfcpp::R_386_TLS_TPOFF32:
1476 case elfcpp::R_386_TLS_DESC:
1477 gold_error(_("%s: unexpected reloc %u in object file"),
1478 object->name().c_str(), r_type);
1479 break;
1481 // These are initial tls relocs, which are expected when
1482 // linking.
1483 case elfcpp::R_386_TLS_GD: // Global-dynamic
1484 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1485 case elfcpp::R_386_TLS_DESC_CALL:
1486 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1487 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1488 case elfcpp::R_386_TLS_IE: // Initial-exec
1489 case elfcpp::R_386_TLS_IE_32:
1490 case elfcpp::R_386_TLS_GOTIE:
1491 case elfcpp::R_386_TLS_LE: // Local-exec
1492 case elfcpp::R_386_TLS_LE_32:
1494 const bool is_final = gsym->final_value_is_known();
1495 const tls::Tls_optimization optimized_type
1496 = Target_i386::optimize_tls_reloc(is_final, r_type);
1497 switch (r_type)
1499 case elfcpp::R_386_TLS_GD: // Global-dynamic
1500 if (optimized_type == tls::TLSOPT_NONE)
1502 // Create a pair of GOT entries for the module index and
1503 // dtv-relative offset.
1504 Output_data_got<32, false>* got
1505 = target->got_section(symtab, layout);
1506 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1507 target->rel_dyn_section(layout),
1508 elfcpp::R_386_TLS_DTPMOD32,
1509 elfcpp::R_386_TLS_DTPOFF32);
1511 else if (optimized_type == tls::TLSOPT_TO_IE)
1513 // Create a GOT entry for the tp-relative offset.
1514 Output_data_got<32, false>* got
1515 = target->got_section(symtab, layout);
1516 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1517 target->rel_dyn_section(layout),
1518 elfcpp::R_386_TLS_TPOFF);
1520 else if (optimized_type != tls::TLSOPT_TO_LE)
1521 unsupported_reloc_global(object, r_type, gsym);
1522 break;
1524 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
1525 target->define_tls_base_symbol(symtab, layout);
1526 if (optimized_type == tls::TLSOPT_NONE)
1528 // Create a double GOT entry with an R_386_TLS_DESC
1529 // reloc. The R_386_TLS_DESC reloc is resolved
1530 // lazily, so the GOT entry needs to be in an area in
1531 // .got.plt, not .got. Call got_section to make sure
1532 // the section has been created.
1533 target->got_section(symtab, layout);
1534 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1535 Reloc_section* rt = target->rel_tls_desc_section(layout);
1536 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
1537 elfcpp::R_386_TLS_DESC, 0);
1539 else if (optimized_type == tls::TLSOPT_TO_IE)
1541 // Create a GOT entry for the tp-relative offset.
1542 Output_data_got<32, false>* got
1543 = target->got_section(symtab, layout);
1544 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1545 target->rel_dyn_section(layout),
1546 elfcpp::R_386_TLS_TPOFF);
1548 else if (optimized_type != tls::TLSOPT_TO_LE)
1549 unsupported_reloc_global(object, r_type, gsym);
1550 break;
1552 case elfcpp::R_386_TLS_DESC_CALL:
1553 break;
1555 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1556 if (optimized_type == tls::TLSOPT_NONE)
1558 // Create a GOT entry for the module index.
1559 target->got_mod_index_entry(symtab, layout, object);
1561 else if (optimized_type != tls::TLSOPT_TO_LE)
1562 unsupported_reloc_global(object, r_type, gsym);
1563 break;
1565 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1566 break;
1568 case elfcpp::R_386_TLS_IE: // Initial-exec
1569 case elfcpp::R_386_TLS_IE_32:
1570 case elfcpp::R_386_TLS_GOTIE:
1571 layout->set_has_static_tls();
1572 if (optimized_type == tls::TLSOPT_NONE)
1574 // For the R_386_TLS_IE relocation, we need to create a
1575 // dynamic relocation when building a shared library.
1576 if (r_type == elfcpp::R_386_TLS_IE
1577 && parameters->options().shared())
1579 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1580 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1581 output_section, object,
1582 data_shndx,
1583 reloc.get_r_offset());
1585 // Create a GOT entry for the tp-relative offset.
1586 Output_data_got<32, false>* got
1587 = target->got_section(symtab, layout);
1588 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1589 ? elfcpp::R_386_TLS_TPOFF32
1590 : elfcpp::R_386_TLS_TPOFF);
1591 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1592 ? GOT_TYPE_TLS_OFFSET
1593 : GOT_TYPE_TLS_NOFFSET);
1594 got->add_global_with_rel(gsym, got_type,
1595 target->rel_dyn_section(layout),
1596 dyn_r_type);
1598 else if (optimized_type != tls::TLSOPT_TO_LE)
1599 unsupported_reloc_global(object, r_type, gsym);
1600 break;
1602 case elfcpp::R_386_TLS_LE: // Local-exec
1603 case elfcpp::R_386_TLS_LE_32:
1604 layout->set_has_static_tls();
1605 if (parameters->options().shared())
1607 // We need to create a dynamic relocation.
1608 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1609 ? elfcpp::R_386_TLS_TPOFF32
1610 : elfcpp::R_386_TLS_TPOFF);
1611 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1612 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1613 data_shndx, reloc.get_r_offset());
1615 break;
1617 default:
1618 gold_unreachable();
1621 break;
1623 case elfcpp::R_386_32PLT:
1624 case elfcpp::R_386_TLS_GD_32:
1625 case elfcpp::R_386_TLS_GD_PUSH:
1626 case elfcpp::R_386_TLS_GD_CALL:
1627 case elfcpp::R_386_TLS_GD_POP:
1628 case elfcpp::R_386_TLS_LDM_32:
1629 case elfcpp::R_386_TLS_LDM_PUSH:
1630 case elfcpp::R_386_TLS_LDM_CALL:
1631 case elfcpp::R_386_TLS_LDM_POP:
1632 case elfcpp::R_386_USED_BY_INTEL_200:
1633 default:
1634 unsupported_reloc_global(object, r_type, gsym);
1635 break;
1639 // Process relocations for gc.
1641 void
1642 Target_i386::gc_process_relocs(Symbol_table* symtab,
1643 Layout* layout,
1644 Sized_relobj<32, false>* object,
1645 unsigned int data_shndx,
1646 unsigned int,
1647 const unsigned char* prelocs,
1648 size_t reloc_count,
1649 Output_section* output_section,
1650 bool needs_special_offset_handling,
1651 size_t local_symbol_count,
1652 const unsigned char* plocal_symbols)
1654 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1655 Target_i386::Scan,
1656 Target_i386::Relocatable_size_for_reloc>(
1657 symtab,
1658 layout,
1659 this,
1660 object,
1661 data_shndx,
1662 prelocs,
1663 reloc_count,
1664 output_section,
1665 needs_special_offset_handling,
1666 local_symbol_count,
1667 plocal_symbols);
1670 // Scan relocations for a section.
1672 void
1673 Target_i386::scan_relocs(Symbol_table* symtab,
1674 Layout* layout,
1675 Sized_relobj<32, false>* object,
1676 unsigned int data_shndx,
1677 unsigned int sh_type,
1678 const unsigned char* prelocs,
1679 size_t reloc_count,
1680 Output_section* output_section,
1681 bool needs_special_offset_handling,
1682 size_t local_symbol_count,
1683 const unsigned char* plocal_symbols)
1685 if (sh_type == elfcpp::SHT_RELA)
1687 gold_error(_("%s: unsupported RELA reloc section"),
1688 object->name().c_str());
1689 return;
1692 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1693 Target_i386::Scan>(
1694 symtab,
1695 layout,
1696 this,
1697 object,
1698 data_shndx,
1699 prelocs,
1700 reloc_count,
1701 output_section,
1702 needs_special_offset_handling,
1703 local_symbol_count,
1704 plocal_symbols);
1707 // Finalize the sections.
1709 void
1710 Target_i386::do_finalize_sections(
1711 Layout* layout,
1712 const Input_objects*,
1713 Symbol_table* symtab)
1715 const Reloc_section* rel_plt = (this->plt_ == NULL
1716 ? NULL
1717 : this->plt_->rel_plt());
1718 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
1719 this->rel_dyn_, true, false);
1721 // Emit any relocs we saved in an attempt to avoid generating COPY
1722 // relocs.
1723 if (this->copy_relocs_.any_saved_relocs())
1724 this->copy_relocs_.emit(this->rel_dyn_section(layout));
1726 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1727 // the .got.plt section.
1728 Symbol* sym = this->global_offset_table_;
1729 if (sym != NULL)
1731 uint32_t data_size = this->got_plt_->current_data_size();
1732 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
1736 // Return whether a direct absolute static relocation needs to be applied.
1737 // In cases where Scan::local() or Scan::global() has created
1738 // a dynamic relocation other than R_386_RELATIVE, the addend
1739 // of the relocation is carried in the data, and we must not
1740 // apply the static relocation.
1742 inline bool
1743 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1744 int ref_flags,
1745 bool is_32bit,
1746 Output_section* output_section)
1748 // If the output section is not allocated, then we didn't call
1749 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1750 // the reloc here.
1751 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1752 return true;
1754 // For local symbols, we will have created a non-RELATIVE dynamic
1755 // relocation only if (a) the output is position independent,
1756 // (b) the relocation is absolute (not pc- or segment-relative), and
1757 // (c) the relocation is not 32 bits wide.
1758 if (gsym == NULL)
1759 return !(parameters->options().output_is_position_independent()
1760 && (ref_flags & Symbol::ABSOLUTE_REF)
1761 && !is_32bit);
1763 // For global symbols, we use the same helper routines used in the
1764 // scan pass. If we did not create a dynamic relocation, or if we
1765 // created a RELATIVE dynamic relocation, we should apply the static
1766 // relocation.
1767 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1768 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1769 && gsym->can_use_relative_reloc(ref_flags
1770 & Symbol::FUNCTION_CALL);
1771 return !has_dyn || is_rel;
1774 // Perform a relocation.
1776 inline bool
1777 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1778 Target_i386* target,
1779 Output_section *output_section,
1780 size_t relnum,
1781 const elfcpp::Rel<32, false>& rel,
1782 unsigned int r_type,
1783 const Sized_symbol<32>* gsym,
1784 const Symbol_value<32>* psymval,
1785 unsigned char* view,
1786 elfcpp::Elf_types<32>::Elf_Addr address,
1787 section_size_type view_size)
1789 if (this->skip_call_tls_get_addr_)
1791 if ((r_type != elfcpp::R_386_PLT32
1792 && r_type != elfcpp::R_386_PC32)
1793 || gsym == NULL
1794 || strcmp(gsym->name(), "___tls_get_addr") != 0)
1795 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1796 _("missing expected TLS relocation"));
1797 else
1799 this->skip_call_tls_get_addr_ = false;
1800 return false;
1804 // Pick the value to use for symbols defined in shared objects.
1805 Symbol_value<32> symval;
1806 if (gsym != NULL
1807 && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1808 || r_type == elfcpp::R_386_PC16
1809 || r_type == elfcpp::R_386_PC32))
1811 symval.set_output_value(target->plt_section()->address()
1812 + gsym->plt_offset());
1813 psymval = &symval;
1816 const Sized_relobj<32, false>* object = relinfo->object;
1818 // Get the GOT offset if needed.
1819 // The GOT pointer points to the end of the GOT section.
1820 // We need to subtract the size of the GOT section to get
1821 // the actual offset to use in the relocation.
1822 bool have_got_offset = false;
1823 unsigned int got_offset = 0;
1824 switch (r_type)
1826 case elfcpp::R_386_GOT32:
1827 if (gsym != NULL)
1829 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1830 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1831 - target->got_size());
1833 else
1835 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1836 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1837 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1838 - target->got_size());
1840 have_got_offset = true;
1841 break;
1843 default:
1844 break;
1847 switch (r_type)
1849 case elfcpp::R_386_NONE:
1850 case elfcpp::R_386_GNU_VTINHERIT:
1851 case elfcpp::R_386_GNU_VTENTRY:
1852 break;
1854 case elfcpp::R_386_32:
1855 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1856 output_section))
1857 Relocate_functions<32, false>::rel32(view, object, psymval);
1858 break;
1860 case elfcpp::R_386_PC32:
1862 int ref_flags = Symbol::NON_PIC_REF;
1863 if (gsym != NULL && gsym->is_func())
1864 ref_flags |= Symbol::FUNCTION_CALL;
1865 if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1866 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1868 break;
1870 case elfcpp::R_386_16:
1871 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1872 output_section))
1873 Relocate_functions<32, false>::rel16(view, object, psymval);
1874 break;
1876 case elfcpp::R_386_PC16:
1878 int ref_flags = Symbol::NON_PIC_REF;
1879 if (gsym != NULL && gsym->is_func())
1880 ref_flags |= Symbol::FUNCTION_CALL;
1881 if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1882 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1884 break;
1886 case elfcpp::R_386_8:
1887 if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1888 output_section))
1889 Relocate_functions<32, false>::rel8(view, object, psymval);
1890 break;
1892 case elfcpp::R_386_PC8:
1894 int ref_flags = Symbol::NON_PIC_REF;
1895 if (gsym != NULL && gsym->is_func())
1896 ref_flags |= Symbol::FUNCTION_CALL;
1897 if (should_apply_static_reloc(gsym, ref_flags, false,
1898 output_section))
1899 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1901 break;
1903 case elfcpp::R_386_PLT32:
1904 gold_assert(gsym == NULL
1905 || gsym->has_plt_offset()
1906 || gsym->final_value_is_known()
1907 || (gsym->is_defined()
1908 && !gsym->is_from_dynobj()
1909 && !gsym->is_preemptible()));
1910 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1911 break;
1913 case elfcpp::R_386_GOT32:
1914 gold_assert(have_got_offset);
1915 Relocate_functions<32, false>::rel32(view, got_offset);
1916 break;
1918 case elfcpp::R_386_GOTOFF:
1920 elfcpp::Elf_types<32>::Elf_Addr value;
1921 value = (psymval->value(object, 0)
1922 - target->got_plt_section()->address());
1923 Relocate_functions<32, false>::rel32(view, value);
1925 break;
1927 case elfcpp::R_386_GOTPC:
1929 elfcpp::Elf_types<32>::Elf_Addr value;
1930 value = target->got_plt_section()->address();
1931 Relocate_functions<32, false>::pcrel32(view, value, address);
1933 break;
1935 case elfcpp::R_386_COPY:
1936 case elfcpp::R_386_GLOB_DAT:
1937 case elfcpp::R_386_JUMP_SLOT:
1938 case elfcpp::R_386_RELATIVE:
1939 // These are outstanding tls relocs, which are unexpected when
1940 // linking.
1941 case elfcpp::R_386_TLS_TPOFF:
1942 case elfcpp::R_386_TLS_DTPMOD32:
1943 case elfcpp::R_386_TLS_DTPOFF32:
1944 case elfcpp::R_386_TLS_TPOFF32:
1945 case elfcpp::R_386_TLS_DESC:
1946 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1947 _("unexpected reloc %u in object file"),
1948 r_type);
1949 break;
1951 // These are initial tls relocs, which are expected when
1952 // linking.
1953 case elfcpp::R_386_TLS_GD: // Global-dynamic
1954 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1955 case elfcpp::R_386_TLS_DESC_CALL:
1956 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1957 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1958 case elfcpp::R_386_TLS_IE: // Initial-exec
1959 case elfcpp::R_386_TLS_IE_32:
1960 case elfcpp::R_386_TLS_GOTIE:
1961 case elfcpp::R_386_TLS_LE: // Local-exec
1962 case elfcpp::R_386_TLS_LE_32:
1963 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1964 view, address, view_size);
1965 break;
1967 case elfcpp::R_386_32PLT:
1968 case elfcpp::R_386_TLS_GD_32:
1969 case elfcpp::R_386_TLS_GD_PUSH:
1970 case elfcpp::R_386_TLS_GD_CALL:
1971 case elfcpp::R_386_TLS_GD_POP:
1972 case elfcpp::R_386_TLS_LDM_32:
1973 case elfcpp::R_386_TLS_LDM_PUSH:
1974 case elfcpp::R_386_TLS_LDM_CALL:
1975 case elfcpp::R_386_TLS_LDM_POP:
1976 case elfcpp::R_386_USED_BY_INTEL_200:
1977 default:
1978 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1979 _("unsupported reloc %u"),
1980 r_type);
1981 break;
1984 return true;
1987 // Perform a TLS relocation.
1989 inline void
1990 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1991 Target_i386* target,
1992 size_t relnum,
1993 const elfcpp::Rel<32, false>& rel,
1994 unsigned int r_type,
1995 const Sized_symbol<32>* gsym,
1996 const Symbol_value<32>* psymval,
1997 unsigned char* view,
1998 elfcpp::Elf_types<32>::Elf_Addr,
1999 section_size_type view_size)
2001 Output_segment* tls_segment = relinfo->layout->tls_segment();
2003 const Sized_relobj<32, false>* object = relinfo->object;
2005 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
2007 const bool is_final = (gsym == NULL
2008 ? !parameters->options().shared()
2009 : gsym->final_value_is_known());
2010 const tls::Tls_optimization optimized_type
2011 = Target_i386::optimize_tls_reloc(is_final, r_type);
2012 switch (r_type)
2014 case elfcpp::R_386_TLS_GD: // Global-dynamic
2015 if (optimized_type == tls::TLSOPT_TO_LE)
2017 gold_assert(tls_segment != NULL);
2018 this->tls_gd_to_le(relinfo, relnum, tls_segment,
2019 rel, r_type, value, view,
2020 view_size);
2021 break;
2023 else
2025 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2026 ? GOT_TYPE_TLS_NOFFSET
2027 : GOT_TYPE_TLS_PAIR);
2028 unsigned int got_offset;
2029 if (gsym != NULL)
2031 gold_assert(gsym->has_got_offset(got_type));
2032 got_offset = gsym->got_offset(got_type) - target->got_size();
2034 else
2036 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2037 gold_assert(object->local_has_got_offset(r_sym, got_type));
2038 got_offset = (object->local_got_offset(r_sym, got_type)
2039 - target->got_size());
2041 if (optimized_type == tls::TLSOPT_TO_IE)
2043 gold_assert(tls_segment != NULL);
2044 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2045 got_offset, view, view_size);
2046 break;
2048 else if (optimized_type == tls::TLSOPT_NONE)
2050 // Relocate the field with the offset of the pair of GOT
2051 // entries.
2052 Relocate_functions<32, false>::rel32(view, got_offset);
2053 break;
2056 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2057 _("unsupported reloc %u"),
2058 r_type);
2059 break;
2061 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2062 case elfcpp::R_386_TLS_DESC_CALL:
2063 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2064 if (optimized_type == tls::TLSOPT_TO_LE)
2066 gold_assert(tls_segment != NULL);
2067 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2068 rel, r_type, value, view,
2069 view_size);
2070 break;
2072 else
2074 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2075 ? GOT_TYPE_TLS_NOFFSET
2076 : GOT_TYPE_TLS_DESC);
2077 unsigned int got_offset = 0;
2078 if (r_type == elfcpp::R_386_TLS_GOTDESC
2079 && optimized_type == tls::TLSOPT_NONE)
2081 // We created GOT entries in the .got.tlsdesc portion of
2082 // the .got.plt section, but the offset stored in the
2083 // symbol is the offset within .got.tlsdesc.
2084 got_offset = (target->got_size()
2085 + target->got_plt_section()->data_size());
2087 if (gsym != NULL)
2089 gold_assert(gsym->has_got_offset(got_type));
2090 got_offset += gsym->got_offset(got_type) - target->got_size();
2092 else
2094 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2095 gold_assert(object->local_has_got_offset(r_sym, got_type));
2096 got_offset += (object->local_got_offset(r_sym, got_type)
2097 - target->got_size());
2099 if (optimized_type == tls::TLSOPT_TO_IE)
2101 gold_assert(tls_segment != NULL);
2102 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2103 got_offset, view, view_size);
2104 break;
2106 else if (optimized_type == tls::TLSOPT_NONE)
2108 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2110 // Relocate the field with the offset of the pair of GOT
2111 // entries.
2112 Relocate_functions<32, false>::rel32(view, got_offset);
2114 break;
2117 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2118 _("unsupported reloc %u"),
2119 r_type);
2120 break;
2122 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2123 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
2125 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2126 _("both SUN and GNU model "
2127 "TLS relocations"));
2128 break;
2130 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2131 if (optimized_type == tls::TLSOPT_TO_LE)
2133 gold_assert(tls_segment != NULL);
2134 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
2135 value, view, view_size);
2136 break;
2138 else if (optimized_type == tls::TLSOPT_NONE)
2140 // Relocate the field with the offset of the GOT entry for
2141 // the module index.
2142 unsigned int got_offset;
2143 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2144 - target->got_size());
2145 Relocate_functions<32, false>::rel32(view, got_offset);
2146 break;
2148 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2149 _("unsupported reloc %u"),
2150 r_type);
2151 break;
2153 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2154 if (optimized_type == tls::TLSOPT_TO_LE)
2156 // This reloc can appear in debugging sections, in which
2157 // case we must not convert to local-exec. We decide what
2158 // to do based on whether the section is marked as
2159 // containing executable code. That is what the GNU linker
2160 // does as well.
2161 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2162 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2164 gold_assert(tls_segment != NULL);
2165 value -= tls_segment->memsz();
2168 Relocate_functions<32, false>::rel32(view, value);
2169 break;
2171 case elfcpp::R_386_TLS_IE: // Initial-exec
2172 case elfcpp::R_386_TLS_GOTIE:
2173 case elfcpp::R_386_TLS_IE_32:
2174 if (optimized_type == tls::TLSOPT_TO_LE)
2176 gold_assert(tls_segment != NULL);
2177 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2178 rel, r_type, value, view,
2179 view_size);
2180 break;
2182 else if (optimized_type == tls::TLSOPT_NONE)
2184 // Relocate the field with the offset of the GOT entry for
2185 // the tp-relative offset of the symbol.
2186 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2187 ? GOT_TYPE_TLS_OFFSET
2188 : GOT_TYPE_TLS_NOFFSET);
2189 unsigned int got_offset;
2190 if (gsym != NULL)
2192 gold_assert(gsym->has_got_offset(got_type));
2193 got_offset = gsym->got_offset(got_type);
2195 else
2197 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2198 gold_assert(object->local_has_got_offset(r_sym, got_type));
2199 got_offset = object->local_got_offset(r_sym, got_type);
2201 // For the R_386_TLS_IE relocation, we need to apply the
2202 // absolute address of the GOT entry.
2203 if (r_type == elfcpp::R_386_TLS_IE)
2204 got_offset += target->got_plt_section()->address();
2205 // All GOT offsets are relative to the end of the GOT.
2206 got_offset -= target->got_size();
2207 Relocate_functions<32, false>::rel32(view, got_offset);
2208 break;
2210 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2211 _("unsupported reloc %u"),
2212 r_type);
2213 break;
2215 case elfcpp::R_386_TLS_LE: // Local-exec
2216 // If we're creating a shared library, a dynamic relocation will
2217 // have been created for this location, so do not apply it now.
2218 if (!parameters->options().shared())
2220 gold_assert(tls_segment != NULL);
2221 value -= tls_segment->memsz();
2222 Relocate_functions<32, false>::rel32(view, value);
2224 break;
2226 case elfcpp::R_386_TLS_LE_32:
2227 // If we're creating a shared library, a dynamic relocation will
2228 // have been created for this location, so do not apply it now.
2229 if (!parameters->options().shared())
2231 gold_assert(tls_segment != NULL);
2232 value = tls_segment->memsz() - value;
2233 Relocate_functions<32, false>::rel32(view, value);
2235 break;
2239 // Do a relocation in which we convert a TLS General-Dynamic to a
2240 // Local-Exec.
2242 inline void
2243 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2244 size_t relnum,
2245 Output_segment* tls_segment,
2246 const elfcpp::Rel<32, false>& rel,
2247 unsigned int,
2248 elfcpp::Elf_types<32>::Elf_Addr value,
2249 unsigned char* view,
2250 section_size_type view_size)
2252 // leal foo(,%reg,1),%eax; call ___tls_get_addr
2253 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2254 // leal foo(%reg),%eax; call ___tls_get_addr
2255 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2257 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2258 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2260 unsigned char op1 = view[-1];
2261 unsigned char op2 = view[-2];
2263 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2264 op2 == 0x8d || op2 == 0x04);
2265 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2267 int roff = 5;
2269 if (op2 == 0x04)
2271 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2272 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2273 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2274 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2275 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2277 else
2279 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2280 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2281 if (rel.get_r_offset() + 9 < view_size
2282 && view[9] == 0x90)
2284 // There is a trailing nop. Use the size byte subl.
2285 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2286 roff = 6;
2288 else
2290 // Use the five byte subl.
2291 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2295 value = tls_segment->memsz() - value;
2296 Relocate_functions<32, false>::rel32(view + roff, value);
2298 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2299 // We can skip it.
2300 this->skip_call_tls_get_addr_ = true;
2303 // Do a relocation in which we convert a TLS General-Dynamic to an
2304 // Initial-Exec.
2306 inline void
2307 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2308 size_t relnum,
2309 Output_segment*,
2310 const elfcpp::Rel<32, false>& rel,
2311 unsigned int,
2312 elfcpp::Elf_types<32>::Elf_Addr value,
2313 unsigned char* view,
2314 section_size_type view_size)
2316 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2317 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2319 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2320 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2322 unsigned char op1 = view[-1];
2323 unsigned char op2 = view[-2];
2325 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2326 op2 == 0x8d || op2 == 0x04);
2327 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2329 int roff = 5;
2331 // FIXME: For now, support only the first (SIB) form.
2332 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2334 if (op2 == 0x04)
2336 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2337 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2338 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2339 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2340 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2342 else
2344 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2345 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2346 if (rel.get_r_offset() + 9 < view_size
2347 && view[9] == 0x90)
2349 // FIXME: This is not the right instruction sequence.
2350 // There is a trailing nop. Use the size byte subl.
2351 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2352 roff = 6;
2354 else
2356 // FIXME: This is not the right instruction sequence.
2357 // Use the five byte subl.
2358 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2362 Relocate_functions<32, false>::rel32(view + roff, value);
2364 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2365 // We can skip it.
2366 this->skip_call_tls_get_addr_ = true;
2369 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2370 // General-Dynamic to a Local-Exec.
2372 inline void
2373 Target_i386::Relocate::tls_desc_gd_to_le(
2374 const Relocate_info<32, false>* relinfo,
2375 size_t relnum,
2376 Output_segment* tls_segment,
2377 const elfcpp::Rel<32, false>& rel,
2378 unsigned int r_type,
2379 elfcpp::Elf_types<32>::Elf_Addr value,
2380 unsigned char* view,
2381 section_size_type view_size)
2383 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2385 // leal foo@TLSDESC(%ebx), %eax
2386 // ==> leal foo@NTPOFF, %eax
2387 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2388 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2389 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2390 view[-2] == 0x8d && view[-1] == 0x83);
2391 view[-1] = 0x05;
2392 value -= tls_segment->memsz();
2393 Relocate_functions<32, false>::rel32(view, value);
2395 else
2397 // call *foo@TLSCALL(%eax)
2398 // ==> nop; nop
2399 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2400 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2401 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2402 view[0] == 0xff && view[1] == 0x10);
2403 view[0] = 0x66;
2404 view[1] = 0x90;
2408 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2409 // General-Dynamic to an Initial-Exec.
2411 inline void
2412 Target_i386::Relocate::tls_desc_gd_to_ie(
2413 const Relocate_info<32, false>* relinfo,
2414 size_t relnum,
2415 Output_segment*,
2416 const elfcpp::Rel<32, false>& rel,
2417 unsigned int r_type,
2418 elfcpp::Elf_types<32>::Elf_Addr value,
2419 unsigned char* view,
2420 section_size_type view_size)
2422 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2424 // leal foo@TLSDESC(%ebx), %eax
2425 // ==> movl foo@GOTNTPOFF(%ebx), %eax
2426 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2427 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2428 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2429 view[-2] == 0x8d && view[-1] == 0x83);
2430 view[-2] = 0x8b;
2431 Relocate_functions<32, false>::rel32(view, value);
2433 else
2435 // call *foo@TLSCALL(%eax)
2436 // ==> nop; nop
2437 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2438 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2439 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2440 view[0] == 0xff && view[1] == 0x10);
2441 view[0] = 0x66;
2442 view[1] = 0x90;
2446 // Do a relocation in which we convert a TLS Local-Dynamic to a
2447 // Local-Exec.
2449 inline void
2450 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2451 size_t relnum,
2452 Output_segment*,
2453 const elfcpp::Rel<32, false>& rel,
2454 unsigned int,
2455 elfcpp::Elf_types<32>::Elf_Addr,
2456 unsigned char* view,
2457 section_size_type view_size)
2459 // leal foo(%reg), %eax; call ___tls_get_addr
2460 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2462 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2463 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2465 // FIXME: Does this test really always pass?
2466 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2467 view[-2] == 0x8d && view[-1] == 0x83);
2469 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2471 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2473 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2474 // We can skip it.
2475 this->skip_call_tls_get_addr_ = true;
2478 // Do a relocation in which we convert a TLS Initial-Exec to a
2479 // Local-Exec.
2481 inline void
2482 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2483 size_t relnum,
2484 Output_segment* tls_segment,
2485 const elfcpp::Rel<32, false>& rel,
2486 unsigned int r_type,
2487 elfcpp::Elf_types<32>::Elf_Addr value,
2488 unsigned char* view,
2489 section_size_type view_size)
2491 // We have to actually change the instructions, which means that we
2492 // need to examine the opcodes to figure out which instruction we
2493 // are looking at.
2494 if (r_type == elfcpp::R_386_TLS_IE)
2496 // movl %gs:XX,%eax ==> movl $YY,%eax
2497 // movl %gs:XX,%reg ==> movl $YY,%reg
2498 // addl %gs:XX,%reg ==> addl $YY,%reg
2499 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2500 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2502 unsigned char op1 = view[-1];
2503 if (op1 == 0xa1)
2505 // movl XX,%eax ==> movl $YY,%eax
2506 view[-1] = 0xb8;
2508 else
2510 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2512 unsigned char op2 = view[-2];
2513 if (op2 == 0x8b)
2515 // movl XX,%reg ==> movl $YY,%reg
2516 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2517 (op1 & 0xc7) == 0x05);
2518 view[-2] = 0xc7;
2519 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2521 else if (op2 == 0x03)
2523 // addl XX,%reg ==> addl $YY,%reg
2524 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2525 (op1 & 0xc7) == 0x05);
2526 view[-2] = 0x81;
2527 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2529 else
2530 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2533 else
2535 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2536 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2537 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2538 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2539 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2541 unsigned char op1 = view[-1];
2542 unsigned char op2 = view[-2];
2543 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2544 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2545 if (op2 == 0x8b)
2547 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
2548 view[-2] = 0xc7;
2549 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2551 else if (op2 == 0x2b)
2553 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
2554 view[-2] = 0x81;
2555 view[-1] = 0xe8 | ((op1 >> 3) & 7);
2557 else if (op2 == 0x03)
2559 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
2560 view[-2] = 0x81;
2561 view[-1] = 0xc0 | ((op1 >> 3) & 7);
2563 else
2564 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2567 value = tls_segment->memsz() - value;
2568 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2569 value = - value;
2571 Relocate_functions<32, false>::rel32(view, value);
2574 // Relocate section data.
2576 void
2577 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2578 unsigned int sh_type,
2579 const unsigned char* prelocs,
2580 size_t reloc_count,
2581 Output_section* output_section,
2582 bool needs_special_offset_handling,
2583 unsigned char* view,
2584 elfcpp::Elf_types<32>::Elf_Addr address,
2585 section_size_type view_size,
2586 const Reloc_symbol_changes* reloc_symbol_changes)
2588 gold_assert(sh_type == elfcpp::SHT_REL);
2590 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2591 Target_i386::Relocate>(
2592 relinfo,
2593 this,
2594 prelocs,
2595 reloc_count,
2596 output_section,
2597 needs_special_offset_handling,
2598 view,
2599 address,
2600 view_size,
2601 reloc_symbol_changes);
2604 // Return the size of a relocation while scanning during a relocatable
2605 // link.
2607 unsigned int
2608 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2609 unsigned int r_type,
2610 Relobj* object)
2612 switch (r_type)
2614 case elfcpp::R_386_NONE:
2615 case elfcpp::R_386_GNU_VTINHERIT:
2616 case elfcpp::R_386_GNU_VTENTRY:
2617 case elfcpp::R_386_TLS_GD: // Global-dynamic
2618 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2619 case elfcpp::R_386_TLS_DESC_CALL:
2620 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2621 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2622 case elfcpp::R_386_TLS_IE: // Initial-exec
2623 case elfcpp::R_386_TLS_IE_32:
2624 case elfcpp::R_386_TLS_GOTIE:
2625 case elfcpp::R_386_TLS_LE: // Local-exec
2626 case elfcpp::R_386_TLS_LE_32:
2627 return 0;
2629 case elfcpp::R_386_32:
2630 case elfcpp::R_386_PC32:
2631 case elfcpp::R_386_GOT32:
2632 case elfcpp::R_386_PLT32:
2633 case elfcpp::R_386_GOTOFF:
2634 case elfcpp::R_386_GOTPC:
2635 return 4;
2637 case elfcpp::R_386_16:
2638 case elfcpp::R_386_PC16:
2639 return 2;
2641 case elfcpp::R_386_8:
2642 case elfcpp::R_386_PC8:
2643 return 1;
2645 // These are relocations which should only be seen by the
2646 // dynamic linker, and should never be seen here.
2647 case elfcpp::R_386_COPY:
2648 case elfcpp::R_386_GLOB_DAT:
2649 case elfcpp::R_386_JUMP_SLOT:
2650 case elfcpp::R_386_RELATIVE:
2651 case elfcpp::R_386_TLS_TPOFF:
2652 case elfcpp::R_386_TLS_DTPMOD32:
2653 case elfcpp::R_386_TLS_DTPOFF32:
2654 case elfcpp::R_386_TLS_TPOFF32:
2655 case elfcpp::R_386_TLS_DESC:
2656 object->error(_("unexpected reloc %u in object file"), r_type);
2657 return 0;
2659 case elfcpp::R_386_32PLT:
2660 case elfcpp::R_386_TLS_GD_32:
2661 case elfcpp::R_386_TLS_GD_PUSH:
2662 case elfcpp::R_386_TLS_GD_CALL:
2663 case elfcpp::R_386_TLS_GD_POP:
2664 case elfcpp::R_386_TLS_LDM_32:
2665 case elfcpp::R_386_TLS_LDM_PUSH:
2666 case elfcpp::R_386_TLS_LDM_CALL:
2667 case elfcpp::R_386_TLS_LDM_POP:
2668 case elfcpp::R_386_USED_BY_INTEL_200:
2669 default:
2670 object->error(_("unsupported reloc %u in object file"), r_type);
2671 return 0;
2675 // Scan the relocs during a relocatable link.
2677 void
2678 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
2679 Layout* layout,
2680 Sized_relobj<32, false>* object,
2681 unsigned int data_shndx,
2682 unsigned int sh_type,
2683 const unsigned char* prelocs,
2684 size_t reloc_count,
2685 Output_section* output_section,
2686 bool needs_special_offset_handling,
2687 size_t local_symbol_count,
2688 const unsigned char* plocal_symbols,
2689 Relocatable_relocs* rr)
2691 gold_assert(sh_type == elfcpp::SHT_REL);
2693 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2694 Relocatable_size_for_reloc> Scan_relocatable_relocs;
2696 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2697 Scan_relocatable_relocs>(
2698 symtab,
2699 layout,
2700 object,
2701 data_shndx,
2702 prelocs,
2703 reloc_count,
2704 output_section,
2705 needs_special_offset_handling,
2706 local_symbol_count,
2707 plocal_symbols,
2708 rr);
2711 // Relocate a section during a relocatable link.
2713 void
2714 Target_i386::relocate_for_relocatable(
2715 const Relocate_info<32, false>* relinfo,
2716 unsigned int sh_type,
2717 const unsigned char* prelocs,
2718 size_t reloc_count,
2719 Output_section* output_section,
2720 off_t offset_in_output_section,
2721 const Relocatable_relocs* rr,
2722 unsigned char* view,
2723 elfcpp::Elf_types<32>::Elf_Addr view_address,
2724 section_size_type view_size,
2725 unsigned char* reloc_view,
2726 section_size_type reloc_view_size)
2728 gold_assert(sh_type == elfcpp::SHT_REL);
2730 gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2731 relinfo,
2732 prelocs,
2733 reloc_count,
2734 output_section,
2735 offset_in_output_section,
2737 view,
2738 view_address,
2739 view_size,
2740 reloc_view,
2741 reloc_view_size);
2744 // Return the value to use for a dynamic which requires special
2745 // treatment. This is how we support equality comparisons of function
2746 // pointers across shared library boundaries, as described in the
2747 // processor specific ABI supplement.
2749 uint64_t
2750 Target_i386::do_dynsym_value(const Symbol* gsym) const
2752 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2753 return this->plt_section()->address() + gsym->plt_offset();
2756 // Return a string used to fill a code section with nops to take up
2757 // the specified length.
2759 std::string
2760 Target_i386::do_code_fill(section_size_type length) const
2762 if (length >= 16)
2764 // Build a jmp instruction to skip over the bytes.
2765 unsigned char jmp[5];
2766 jmp[0] = 0xe9;
2767 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2768 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2769 + std::string(length - 5, '\0'));
2772 // Nop sequences of various lengths.
2773 const char nop1[1] = { 0x90 }; // nop
2774 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2775 const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
2776 const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
2777 const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
2778 0x00 }; // leal 0(%esi,1),%esi
2779 const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2780 0x00, 0x00 };
2781 const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2782 0x00, 0x00, 0x00 };
2783 const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
2784 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2785 const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
2786 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
2787 0x00 };
2788 const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2789 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2790 0x00, 0x00 };
2791 const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2792 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2793 0x00, 0x00, 0x00 };
2794 const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2795 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2796 0x00, 0x00, 0x00, 0x00 };
2797 const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2798 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2799 0x27, 0x00, 0x00, 0x00,
2800 0x00 };
2801 const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2802 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2803 0xbc, 0x27, 0x00, 0x00,
2804 0x00, 0x00 };
2805 const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2806 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2807 0x90, 0x90, 0x90, 0x90,
2808 0x90, 0x90, 0x90 };
2810 const char* nops[16] = {
2811 NULL,
2812 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2813 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2816 return std::string(nops[length], length);
2819 // Return whether SYM should be treated as a call to a non-split
2820 // function. We don't want that to be true of a call to a
2821 // get_pc_thunk function.
2823 bool
2824 Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
2826 return (sym->type() == elfcpp::STT_FUNC
2827 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
2830 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2831 // compiled with -fstack-split. The function calls non-stack-split
2832 // code. We have to change the function so that it always ensures
2833 // that it has enough stack space to run some random function.
2835 void
2836 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2837 section_offset_type fnoffset,
2838 section_size_type fnsize,
2839 unsigned char* view,
2840 section_size_type view_size,
2841 std::string* from,
2842 std::string* to) const
2844 // The function starts with a comparison of the stack pointer and a
2845 // field in the TCB. This is followed by a jump.
2847 // cmp %gs:NN,%esp
2848 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2849 && fnsize > 7)
2851 // We will call __morestack if the carry flag is set after this
2852 // comparison. We turn the comparison into an stc instruction
2853 // and some nops.
2854 view[fnoffset] = '\xf9';
2855 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2857 // lea NN(%esp),%ecx
2858 // lea NN(%esp),%edx
2859 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2860 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
2861 && fnsize > 7)
2863 // This is loading an offset from the stack pointer for a
2864 // comparison. The offset is negative, so we decrease the
2865 // offset by the amount of space we need for the stack. This
2866 // means we will avoid calling __morestack if there happens to
2867 // be plenty of space on the stack already.
2868 unsigned char* pval = view + fnoffset + 3;
2869 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2870 val -= parameters->options().split_stack_adjust_size();
2871 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2873 else
2875 if (!object->has_no_split_stack())
2876 object->error(_("failed to match split-stack sequence at "
2877 "section %u offset %0zx"),
2878 shndx, static_cast<size_t>(fnoffset));
2879 return;
2882 // We have to change the function so that it calls
2883 // __morestack_non_split instead of __morestack. The former will
2884 // allocate additional stack space.
2885 *from = "__morestack";
2886 *to = "__morestack_non_split";
2889 // The selector for i386 object files.
2891 class Target_selector_i386 : public Target_selector_freebsd
2893 public:
2894 Target_selector_i386()
2895 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2896 "elf32-i386", "elf32-i386-freebsd")
2899 Target*
2900 do_instantiate_target()
2901 { return new Target_i386(); }
2904 Target_selector_i386 target_selector_i386;
2906 } // End anonymous namespace.