1 // i386.cc -- i386 target support for gold.
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
30 #include "parameters.h"
37 #include "copy-relocs.h"
39 #include "target-reloc.h"
40 #include "target-select.h"
51 // A class to handle the PLT data.
52 // This is an abstract base class that handles most of the linker details
53 // but does not know the actual contents of PLT entries. The derived
54 // classes below fill in those details.
56 class Output_data_plt_i386 : public Output_section_data
59 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
61 Output_data_plt_i386(Layout*, uint64_t addralign,
62 Output_data_space*, Output_data_space*);
64 // Add an entry to the PLT.
66 add_entry(Symbol_table*, Layout*, Symbol* gsym);
68 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
70 add_local_ifunc_entry(Symbol_table*, Layout*,
71 Sized_relobj_file<32, false>* relobj,
72 unsigned int local_sym_index);
74 // Return the .rel.plt section data.
77 { return this->rel_; }
79 // Return where the TLS_DESC relocations should go.
81 rel_tls_desc(Layout*);
83 // Return where the IRELATIVE relocations should go.
85 rel_irelative(Symbol_table*, Layout*);
87 // Return whether we created a section for IRELATIVE relocations.
89 has_irelative_section() const
90 { return this->irelative_rel_ != NULL; }
92 // Return the number of PLT entries.
95 { return this->count_ + this->irelative_count_; }
97 // Return the offset of the first non-reserved PLT entry.
99 first_plt_entry_offset()
100 { return this->get_plt_entry_size(); }
102 // Return the size of a PLT entry.
104 get_plt_entry_size() const
105 { return this->do_get_plt_entry_size(); }
107 // Return the PLT address to use for a global symbol.
109 address_for_global(const Symbol*);
111 // Return the PLT address to use for a local symbol.
113 address_for_local(const Relobj*, unsigned int symndx);
115 // Add .eh_frame information for the PLT.
117 add_eh_frame(Layout* layout)
118 { this->do_add_eh_frame(layout); }
121 // Fill the first PLT entry, given the pointer to the PLT section data
122 // and the runtime address of the GOT.
124 fill_first_plt_entry(unsigned char* pov,
125 elfcpp::Elf_types<32>::Elf_Addr got_address)
126 { this->do_fill_first_plt_entry(pov, got_address); }
128 // Fill a normal PLT entry, given the pointer to the entry's data in the
129 // section, the runtime address of the GOT, the offset into the GOT of
130 // the corresponding slot, the offset into the relocation section of the
131 // corresponding reloc, and the offset of this entry within the whole
132 // PLT. Return the offset from this PLT entry's runtime address that
133 // should be used to compute the initial value of the GOT slot.
135 fill_plt_entry(unsigned char* pov,
136 elfcpp::Elf_types<32>::Elf_Addr got_address,
137 unsigned int got_offset,
138 unsigned int plt_offset,
139 unsigned int plt_rel_offset)
141 return this->do_fill_plt_entry(pov, got_address, got_offset,
142 plt_offset, plt_rel_offset);
146 do_get_plt_entry_size() const = 0;
149 do_fill_first_plt_entry(unsigned char* pov,
150 elfcpp::Elf_types<32>::Elf_Addr got_address) = 0;
153 do_fill_plt_entry(unsigned char* pov,
154 elfcpp::Elf_types<32>::Elf_Addr got_address,
155 unsigned int got_offset,
156 unsigned int plt_offset,
157 unsigned int plt_rel_offset) = 0;
160 do_add_eh_frame(Layout*) = 0;
163 do_adjust_output_section(Output_section* os);
165 // Write to a map file.
167 do_print_to_mapfile(Mapfile* mapfile) const
168 { mapfile->print_output_data(this, _("** PLT")); }
170 // The .eh_frame unwind information for the PLT.
171 // The CIE is common across variants of the PLT format.
172 static const int plt_eh_frame_cie_size = 16;
173 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
176 // Set the final size.
178 set_final_data_size()
180 this->set_data_size((this->count_ + this->irelative_count_ + 1)
181 * this->get_plt_entry_size());
184 // Write out the PLT data.
186 do_write(Output_file*);
188 // We keep a list of global STT_GNU_IFUNC symbols, each with its
189 // offset in the GOT.
193 unsigned int got_offset;
196 // We keep a list of local STT_GNU_IFUNC symbols, each with its
197 // offset in the GOT.
200 Sized_relobj_file<32, false>* object;
201 unsigned int local_sym_index;
202 unsigned int got_offset;
205 // A pointer to the Layout class, so that we can find the .dynamic
206 // section when we write out the GOT PLT section.
208 // The reloc section.
210 // The TLS_DESC relocations, if necessary. These must follow the
211 // regular PLT relocs.
212 Reloc_section* tls_desc_rel_;
213 // The IRELATIVE relocations, if necessary. These must follow the
214 // regular relocatoins and the TLS_DESC relocations.
215 Reloc_section* irelative_rel_;
216 // The .got.plt section.
217 Output_data_space* got_plt_;
218 // The part of the .got.plt section used for IRELATIVE relocs.
219 Output_data_space* got_irelative_;
220 // The number of PLT entries.
222 // Number of PLT entries with R_386_IRELATIVE relocs. These follow
223 // the regular PLT entries.
224 unsigned int irelative_count_;
225 // Global STT_GNU_IFUNC symbols.
226 std::vector<Global_ifunc> global_ifuncs_;
227 // Local STT_GNU_IFUNC symbols.
228 std::vector<Local_ifunc> local_ifuncs_;
231 // This is an abstract class for the standard PLT layout.
232 // The derived classes below handle the actual PLT contents
233 // for the executable (non-PIC) and shared-library (PIC) cases.
234 // The unwind information is uniform across those two, so it's here.
236 class Output_data_plt_i386_standard : public Output_data_plt_i386
239 Output_data_plt_i386_standard(Layout* layout,
240 Output_data_space* got_plt,
241 Output_data_space* got_irelative)
242 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
247 do_get_plt_entry_size() const
248 { return plt_entry_size; }
251 do_add_eh_frame(Layout* layout)
253 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
254 plt_eh_frame_fde, plt_eh_frame_fde_size);
257 // The size of an entry in the PLT.
258 static const int plt_entry_size = 16;
260 // The .eh_frame unwind information for the PLT.
261 static const int plt_eh_frame_fde_size = 32;
262 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
265 // Actually fill the PLT contents for an executable (non-PIC).
267 class Output_data_plt_i386_exec : public Output_data_plt_i386_standard
270 Output_data_plt_i386_exec(Layout* layout,
271 Output_data_space* got_plt,
272 Output_data_space* got_irelative)
273 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
278 do_fill_first_plt_entry(unsigned char* pov,
279 elfcpp::Elf_types<32>::Elf_Addr got_address);
282 do_fill_plt_entry(unsigned char* pov,
283 elfcpp::Elf_types<32>::Elf_Addr got_address,
284 unsigned int got_offset,
285 unsigned int plt_offset,
286 unsigned int plt_rel_offset);
289 // The first entry in the PLT for an executable.
290 static const unsigned char first_plt_entry[plt_entry_size];
292 // Other entries in the PLT for an executable.
293 static const unsigned char plt_entry[plt_entry_size];
296 // Actually fill the PLT contents for a shared library (PIC).
298 class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard
301 Output_data_plt_i386_dyn(Layout* layout,
302 Output_data_space* got_plt,
303 Output_data_space* got_irelative)
304 : Output_data_plt_i386_standard(layout, got_plt, got_irelative)
309 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
312 do_fill_plt_entry(unsigned char* pov,
313 elfcpp::Elf_types<32>::Elf_Addr,
314 unsigned int got_offset,
315 unsigned int plt_offset,
316 unsigned int plt_rel_offset);
319 // The first entry in the PLT for a shared object.
320 static const unsigned char first_plt_entry[plt_entry_size];
322 // Other entries in the PLT for a shared object.
323 static const unsigned char plt_entry[plt_entry_size];
326 // The i386 target class.
327 // TLS info comes from
328 // http://people.redhat.com/drepper/tls.pdf
329 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
331 class Target_i386 : public Sized_target<32, false>
334 typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
336 Target_i386(const Target::Target_info* info = &i386_info)
337 : Sized_target<32, false>(info),
338 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
339 got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL),
340 rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
341 got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
344 // Process the relocations to determine unreferenced sections for
345 // garbage collection.
347 gc_process_relocs(Symbol_table* symtab,
349 Sized_relobj_file<32, false>* object,
350 unsigned int data_shndx,
351 unsigned int sh_type,
352 const unsigned char* prelocs,
354 Output_section* output_section,
355 bool needs_special_offset_handling,
356 size_t local_symbol_count,
357 const unsigned char* plocal_symbols);
359 // Scan the relocations to look for symbol adjustments.
361 scan_relocs(Symbol_table* symtab,
363 Sized_relobj_file<32, false>* object,
364 unsigned int data_shndx,
365 unsigned int sh_type,
366 const unsigned char* prelocs,
368 Output_section* output_section,
369 bool needs_special_offset_handling,
370 size_t local_symbol_count,
371 const unsigned char* plocal_symbols);
373 // Finalize the sections.
375 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
377 // Return the value to use for a dynamic which requires special
380 do_dynsym_value(const Symbol*) const;
382 // Relocate a section.
384 relocate_section(const Relocate_info<32, false>*,
385 unsigned int sh_type,
386 const unsigned char* prelocs,
388 Output_section* output_section,
389 bool needs_special_offset_handling,
391 elfcpp::Elf_types<32>::Elf_Addr view_address,
392 section_size_type view_size,
393 const Reloc_symbol_changes*);
395 // Scan the relocs during a relocatable link.
397 scan_relocatable_relocs(Symbol_table* symtab,
399 Sized_relobj_file<32, false>* object,
400 unsigned int data_shndx,
401 unsigned int sh_type,
402 const unsigned char* prelocs,
404 Output_section* output_section,
405 bool needs_special_offset_handling,
406 size_t local_symbol_count,
407 const unsigned char* plocal_symbols,
408 Relocatable_relocs*);
410 // Relocate a section during a relocatable link.
412 relocate_for_relocatable(const Relocate_info<32, false>*,
413 unsigned int sh_type,
414 const unsigned char* prelocs,
416 Output_section* output_section,
417 elfcpp::Elf_types<32>::Elf_Off
418 offset_in_output_section,
419 const Relocatable_relocs*,
421 elfcpp::Elf_types<32>::Elf_Addr view_address,
422 section_size_type view_size,
423 unsigned char* reloc_view,
424 section_size_type reloc_view_size);
426 // Return a string used to fill a code section with nops.
428 do_code_fill(section_size_type length) const;
430 // Return whether SYM is defined by the ABI.
432 do_is_defined_by_abi(const Symbol* sym) const
433 { return strcmp(sym->name(), "___tls_get_addr") == 0; }
435 // Return whether a symbol name implies a local label. The UnixWare
436 // 2.1 cc generates temporary symbols that start with .X, so we
437 // recognize them here. FIXME: do other SVR4 compilers also use .X?.
438 // If so, we should move the .X recognition into
439 // Target::do_is_local_label_name.
441 do_is_local_label_name(const char* name) const
443 if (name[0] == '.' && name[1] == 'X')
445 return Target::do_is_local_label_name(name);
448 // Return the PLT address to use for a global symbol.
450 do_plt_address_for_global(const Symbol* gsym) const
451 { return this->plt_section()->address_for_global(gsym); }
454 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
455 { return this->plt_section()->address_for_local(relobj, symndx); }
457 // We can tell whether we take the address of a function.
459 do_can_check_for_function_pointers() const
462 // Return the base for a DW_EH_PE_datarel encoding.
464 do_ehframe_datarel_base() const;
466 // Return whether SYM is call to a non-split function.
468 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
470 // Adjust -fsplit-stack code which calls non-split-stack code.
472 do_calls_non_split(Relobj* object, unsigned int shndx,
473 section_offset_type fnoffset, section_size_type fnsize,
474 unsigned char* view, section_size_type view_size,
475 std::string* from, std::string* to) const;
477 // Return the size of the GOT section.
481 gold_assert(this->got_ != NULL);
482 return this->got_->data_size();
485 // Return the number of entries in the GOT.
487 got_entry_count() const
489 if (this->got_ == NULL)
491 return this->got_size() / 4;
494 // Return the number of entries in the PLT.
496 plt_entry_count() const;
498 // Return the offset of the first non-reserved PLT entry.
500 first_plt_entry_offset() const;
502 // Return the size of each PLT entry.
504 plt_entry_size() const;
507 // Instantiate the plt_ member.
508 // This chooses the right PLT flavor for an executable or a shared object.
509 Output_data_plt_i386*
510 make_data_plt(Layout* layout,
511 Output_data_space* got_plt,
512 Output_data_space* got_irelative,
514 { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); }
516 virtual Output_data_plt_i386*
517 do_make_data_plt(Layout* layout,
518 Output_data_space* got_plt,
519 Output_data_space* got_irelative,
523 return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative);
525 return new Output_data_plt_i386_exec(layout, got_plt, got_irelative);
529 // The class which scans relocations.
534 get_reference_flags(unsigned int r_type);
537 local(Symbol_table* symtab, Layout* layout, Target_i386* target,
538 Sized_relobj_file<32, false>* object,
539 unsigned int data_shndx,
540 Output_section* output_section,
541 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
542 const elfcpp::Sym<32, false>& lsym);
545 global(Symbol_table* symtab, Layout* layout, Target_i386* target,
546 Sized_relobj_file<32, false>* object,
547 unsigned int data_shndx,
548 Output_section* output_section,
549 const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
553 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
555 Sized_relobj_file<32, false>* object,
556 unsigned int data_shndx,
557 Output_section* output_section,
558 const elfcpp::Rel<32, false>& reloc,
560 const elfcpp::Sym<32, false>& lsym);
563 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
565 Sized_relobj_file<32, false>* object,
566 unsigned int data_shndx,
567 Output_section* output_section,
568 const elfcpp::Rel<32, false>& reloc,
573 possible_function_pointer_reloc(unsigned int r_type);
576 reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*,
577 unsigned int r_type);
580 unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type);
583 unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type,
587 // The class which implements relocation.
592 : skip_call_tls_get_addr_(false),
593 local_dynamic_type_(LOCAL_DYNAMIC_NONE)
598 if (this->skip_call_tls_get_addr_)
600 // FIXME: This needs to specify the location somehow.
601 gold_error(_("missing expected TLS relocation"));
605 // Return whether the static relocation needs to be applied.
607 should_apply_static_reloc(const Sized_symbol<32>* gsym,
610 Output_section* output_section);
612 // Do a relocation. Return false if the caller should not issue
613 // any warnings about this relocation.
615 relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
616 size_t relnum, const elfcpp::Rel<32, false>&,
617 unsigned int r_type, const Sized_symbol<32>*,
618 const Symbol_value<32>*,
619 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
623 // Do a TLS relocation.
625 relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
626 size_t relnum, const elfcpp::Rel<32, false>&,
627 unsigned int r_type, const Sized_symbol<32>*,
628 const Symbol_value<32>*,
629 unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
632 // Do a TLS General-Dynamic to Initial-Exec transition.
634 tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
635 Output_segment* tls_segment,
636 const elfcpp::Rel<32, false>&, unsigned int r_type,
637 elfcpp::Elf_types<32>::Elf_Addr value,
639 section_size_type view_size);
641 // Do a TLS General-Dynamic to Local-Exec transition.
643 tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
644 Output_segment* tls_segment,
645 const elfcpp::Rel<32, false>&, unsigned int r_type,
646 elfcpp::Elf_types<32>::Elf_Addr value,
648 section_size_type view_size);
650 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
653 tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
654 Output_segment* tls_segment,
655 const elfcpp::Rel<32, false>&, unsigned int r_type,
656 elfcpp::Elf_types<32>::Elf_Addr value,
658 section_size_type view_size);
660 // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
663 tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
664 Output_segment* tls_segment,
665 const elfcpp::Rel<32, false>&, unsigned int r_type,
666 elfcpp::Elf_types<32>::Elf_Addr value,
668 section_size_type view_size);
670 // Do a TLS Local-Dynamic to Local-Exec transition.
672 tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
673 Output_segment* tls_segment,
674 const elfcpp::Rel<32, false>&, unsigned int r_type,
675 elfcpp::Elf_types<32>::Elf_Addr value,
677 section_size_type view_size);
679 // Do a TLS Initial-Exec to Local-Exec transition.
681 tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
682 Output_segment* tls_segment,
683 const elfcpp::Rel<32, false>&, unsigned int r_type,
684 elfcpp::Elf_types<32>::Elf_Addr value,
686 section_size_type view_size);
688 // We need to keep track of which type of local dynamic relocation
689 // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
690 enum Local_dynamic_type
697 // This is set if we should skip the next reloc, which should be a
698 // PLT32 reloc against ___tls_get_addr.
699 bool skip_call_tls_get_addr_;
700 // The type of local dynamic relocation we have seen in the section
701 // being relocated, if any.
702 Local_dynamic_type local_dynamic_type_;
705 // A class which returns the size required for a relocation type,
706 // used while scanning relocs during a relocatable link.
707 class Relocatable_size_for_reloc
711 get_size_for_reloc(unsigned int, Relobj*);
714 // Adjust TLS relocation type based on the options and whether this
715 // is a local symbol.
716 static tls::Tls_optimization
717 optimize_tls_reloc(bool is_final, int r_type);
719 // Get the GOT section, creating it if necessary.
720 Output_data_got<32, false>*
721 got_section(Symbol_table*, Layout*);
723 // Get the GOT PLT section.
725 got_plt_section() const
727 gold_assert(this->got_plt_ != NULL);
728 return this->got_plt_;
731 // Get the GOT section for TLSDESC entries.
732 Output_data_got<32, false>*
733 got_tlsdesc_section() const
735 gold_assert(this->got_tlsdesc_ != NULL);
736 return this->got_tlsdesc_;
739 // Create the PLT section.
741 make_plt_section(Symbol_table* symtab, Layout* layout);
743 // Create a PLT entry for a global symbol.
745 make_plt_entry(Symbol_table*, Layout*, Symbol*);
747 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
749 make_local_ifunc_plt_entry(Symbol_table*, Layout*,
750 Sized_relobj_file<32, false>* relobj,
751 unsigned int local_sym_index);
753 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
755 define_tls_base_symbol(Symbol_table*, Layout*);
757 // Create a GOT entry for the TLS module index.
759 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
760 Sized_relobj_file<32, false>* object);
762 // Get the PLT section.
763 Output_data_plt_i386*
766 gold_assert(this->plt_ != NULL);
770 // Get the dynamic reloc section, creating it if necessary.
772 rel_dyn_section(Layout*);
774 // Get the section to use for TLS_DESC relocations.
776 rel_tls_desc_section(Layout*) const;
778 // Get the section to use for IRELATIVE relocations.
780 rel_irelative_section(Layout*);
782 // Add a potential copy relocation.
784 copy_reloc(Symbol_table* symtab, Layout* layout,
785 Sized_relobj_file<32, false>* object,
786 unsigned int shndx, Output_section* output_section,
787 Symbol* sym, const elfcpp::Rel<32, false>& reloc)
789 this->copy_relocs_.copy_reloc(symtab, layout,
790 symtab->get_sized_symbol<32>(sym),
791 object, shndx, output_section, reloc,
792 this->rel_dyn_section(layout));
795 // Information about this specific target which we pass to the
796 // general Target structure.
797 static const Target::Target_info i386_info;
799 // The types of GOT entries needed for this platform.
800 // These values are exposed to the ABI in an incremental link.
801 // Do not renumber existing values without changing the version
802 // number of the .gnu_incremental_inputs section.
805 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
806 GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset
807 GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset
808 GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair
809 GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair
813 Output_data_got<32, false>* got_;
815 Output_data_plt_i386* plt_;
816 // The GOT PLT section.
817 Output_data_space* got_plt_;
818 // The GOT section for IRELATIVE relocations.
819 Output_data_space* got_irelative_;
820 // The GOT section for TLSDESC relocations.
821 Output_data_got<32, false>* got_tlsdesc_;
822 // The _GLOBAL_OFFSET_TABLE_ symbol.
823 Symbol* global_offset_table_;
824 // The dynamic reloc section.
825 Reloc_section* rel_dyn_;
826 // The section to use for IRELATIVE relocs.
827 Reloc_section* rel_irelative_;
828 // Relocs saved to avoid a COPY reloc.
829 Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
830 // Space for variables copied with a COPY reloc.
831 Output_data_space* dynbss_;
832 // Offset of the GOT entry for the TLS module index.
833 unsigned int got_mod_index_offset_;
834 // True if the _TLS_MODULE_BASE_ symbol has been defined.
835 bool tls_base_symbol_defined_;
838 const Target::Target_info Target_i386::i386_info =
841 false, // is_big_endian
842 elfcpp::EM_386, // machine_code
843 false, // has_make_symbol
844 false, // has_resolve
845 true, // has_code_fill
846 true, // is_default_stack_executable
847 true, // can_icf_inline_merge_sections
849 "/usr/lib/libc.so.1", // dynamic_linker
850 0x08048000, // default_text_segment_address
851 0x1000, // abi_pagesize (overridable by -z max-page-size)
852 0x1000, // common_pagesize (overridable by -z common-page-size)
853 false, // isolate_execinstr
855 elfcpp::SHN_UNDEF, // small_common_shndx
856 elfcpp::SHN_UNDEF, // large_common_shndx
857 0, // small_common_section_flags
858 0, // large_common_section_flags
859 NULL, // attributes_section
860 NULL // attributes_vendor
863 // Get the GOT section, creating it if necessary.
865 Output_data_got<32, false>*
866 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
868 if (this->got_ == NULL)
870 gold_assert(symtab != NULL && layout != NULL);
872 this->got_ = new Output_data_got<32, false>();
874 // When using -z now, we can treat .got.plt as a relro section.
875 // Without -z now, it is modified after program startup by lazy
877 bool is_got_plt_relro = parameters->options().now();
878 Output_section_order got_order = (is_got_plt_relro
881 Output_section_order got_plt_order = (is_got_plt_relro
883 : ORDER_NON_RELRO_FIRST);
885 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
887 | elfcpp::SHF_WRITE),
888 this->got_, got_order, true);
890 this->got_plt_ = new Output_data_space(4, "** GOT PLT");
891 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
893 | elfcpp::SHF_WRITE),
894 this->got_plt_, got_plt_order,
897 // The first three entries are reserved.
898 this->got_plt_->set_current_data_size(3 * 4);
900 if (!is_got_plt_relro)
902 // Those bytes can go into the relro segment.
903 layout->increase_relro(3 * 4);
906 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
907 this->global_offset_table_ =
908 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
909 Symbol_table::PREDEFINED,
911 0, 0, elfcpp::STT_OBJECT,
913 elfcpp::STV_HIDDEN, 0,
916 // If there are any IRELATIVE relocations, they get GOT entries
917 // in .got.plt after the jump slot relocations.
918 this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT");
919 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
921 | elfcpp::SHF_WRITE),
922 this->got_irelative_,
923 got_plt_order, is_got_plt_relro);
925 // If there are any TLSDESC relocations, they get GOT entries in
926 // .got.plt after the jump slot entries.
927 this->got_tlsdesc_ = new Output_data_got<32, false>();
928 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
930 | elfcpp::SHF_WRITE),
932 got_plt_order, is_got_plt_relro);
938 // Get the dynamic reloc section, creating it if necessary.
940 Target_i386::Reloc_section*
941 Target_i386::rel_dyn_section(Layout* layout)
943 if (this->rel_dyn_ == NULL)
945 gold_assert(layout != NULL);
946 this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
947 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
948 elfcpp::SHF_ALLOC, this->rel_dyn_,
949 ORDER_DYNAMIC_RELOCS, false);
951 return this->rel_dyn_;
954 // Get the section to use for IRELATIVE relocs, creating it if
955 // necessary. These go in .rel.dyn, but only after all other dynamic
956 // relocations. They need to follow the other dynamic relocations so
957 // that they can refer to global variables initialized by those
960 Target_i386::Reloc_section*
961 Target_i386::rel_irelative_section(Layout* layout)
963 if (this->rel_irelative_ == NULL)
965 // Make sure we have already create the dynamic reloc section.
966 this->rel_dyn_section(layout);
967 this->rel_irelative_ = new Reloc_section(false);
968 layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
969 elfcpp::SHF_ALLOC, this->rel_irelative_,
970 ORDER_DYNAMIC_RELOCS, false);
971 gold_assert(this->rel_dyn_->output_section()
972 == this->rel_irelative_->output_section());
974 return this->rel_irelative_;
977 // Create the PLT section. The ordinary .got section is an argument,
978 // since we need to refer to the start. We also create our own .got
979 // section just for PLT entries.
981 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
983 Output_data_space* got_plt,
984 Output_data_space* got_irelative)
985 : Output_section_data(addralign),
986 layout_(layout), tls_desc_rel_(NULL),
987 irelative_rel_(NULL), got_plt_(got_plt), got_irelative_(got_irelative),
988 count_(0), irelative_count_(0), global_ifuncs_(), local_ifuncs_()
990 this->rel_ = new Reloc_section(false);
991 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
992 elfcpp::SHF_ALLOC, this->rel_,
993 ORDER_DYNAMIC_PLT_RELOCS, false);
997 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
999 // UnixWare sets the entsize of .plt to 4, and so does the old GNU
1000 // linker, and so do we.
1004 // Add an entry to the PLT.
1007 Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
1010 gold_assert(!gsym->has_plt_offset());
1012 // Every PLT entry needs a reloc.
1013 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1014 && gsym->can_use_relative_reloc(false))
1016 gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size());
1017 ++this->irelative_count_;
1018 section_offset_type got_offset =
1019 this->got_irelative_->current_data_size();
1020 this->got_irelative_->set_current_data_size(got_offset + 4);
1021 Reloc_section* rel = this->rel_irelative(symtab, layout);
1022 rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
1023 this->got_irelative_, got_offset);
1024 struct Global_ifunc gi;
1026 gi.got_offset = got_offset;
1027 this->global_ifuncs_.push_back(gi);
1031 // When setting the PLT offset we skip the initial reserved PLT
1033 gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size());
1037 section_offset_type got_offset = this->got_plt_->current_data_size();
1039 // Every PLT entry needs a GOT entry which points back to the
1040 // PLT entry (this will be changed by the dynamic linker,
1041 // normally lazily when the function is called).
1042 this->got_plt_->set_current_data_size(got_offset + 4);
1044 gsym->set_needs_dynsym_entry();
1045 this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
1049 // Note that we don't need to save the symbol. The contents of the
1050 // PLT are independent of which symbols are used. The symbols only
1051 // appear in the relocations.
1054 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
1058 Output_data_plt_i386::add_local_ifunc_entry(
1059 Symbol_table* symtab,
1061 Sized_relobj_file<32, false>* relobj,
1062 unsigned int local_sym_index)
1064 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size();
1065 ++this->irelative_count_;
1067 section_offset_type got_offset = this->got_irelative_->current_data_size();
1069 // Every PLT entry needs a GOT entry which points back to the PLT
1071 this->got_irelative_->set_current_data_size(got_offset + 4);
1073 // Every PLT entry needs a reloc.
1074 Reloc_section* rel = this->rel_irelative(symtab, layout);
1075 rel->add_symbolless_local_addend(relobj, local_sym_index,
1076 elfcpp::R_386_IRELATIVE,
1077 this->got_irelative_, got_offset);
1079 struct Local_ifunc li;
1081 li.local_sym_index = local_sym_index;
1082 li.got_offset = got_offset;
1083 this->local_ifuncs_.push_back(li);
1088 // Return where the TLS_DESC relocations should go, creating it if
1089 // necessary. These follow the JUMP_SLOT relocations.
1091 Output_data_plt_i386::Reloc_section*
1092 Output_data_plt_i386::rel_tls_desc(Layout* layout)
1094 if (this->tls_desc_rel_ == NULL)
1096 this->tls_desc_rel_ = new Reloc_section(false);
1097 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1098 elfcpp::SHF_ALLOC, this->tls_desc_rel_,
1099 ORDER_DYNAMIC_PLT_RELOCS, false);
1100 gold_assert(this->tls_desc_rel_->output_section()
1101 == this->rel_->output_section());
1103 return this->tls_desc_rel_;
1106 // Return where the IRELATIVE relocations should go in the PLT. These
1107 // follow the JUMP_SLOT and TLS_DESC relocations.
1109 Output_data_plt_i386::Reloc_section*
1110 Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
1112 if (this->irelative_rel_ == NULL)
1114 // Make sure we have a place for the TLS_DESC relocations, in
1115 // case we see any later on.
1116 this->rel_tls_desc(layout);
1117 this->irelative_rel_ = new Reloc_section(false);
1118 layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
1119 elfcpp::SHF_ALLOC, this->irelative_rel_,
1120 ORDER_DYNAMIC_PLT_RELOCS, false);
1121 gold_assert(this->irelative_rel_->output_section()
1122 == this->rel_->output_section());
1124 if (parameters->doing_static_link())
1126 // A statically linked executable will only have a .rel.plt
1127 // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
1128 // symbols. The library will use these symbols to locate
1129 // the IRELATIVE relocs at program startup time.
1130 symtab->define_in_output_data("__rel_iplt_start", NULL,
1131 Symbol_table::PREDEFINED,
1132 this->irelative_rel_, 0, 0,
1133 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1134 elfcpp::STV_HIDDEN, 0, false, true);
1135 symtab->define_in_output_data("__rel_iplt_end", NULL,
1136 Symbol_table::PREDEFINED,
1137 this->irelative_rel_, 0, 0,
1138 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1139 elfcpp::STV_HIDDEN, 0, true, true);
1142 return this->irelative_rel_;
1145 // Return the PLT address to use for a global symbol.
1148 Output_data_plt_i386::address_for_global(const Symbol* gsym)
1150 uint64_t offset = 0;
1151 if (gsym->type() == elfcpp::STT_GNU_IFUNC
1152 && gsym->can_use_relative_reloc(false))
1153 offset = (this->count_ + 1) * this->get_plt_entry_size();
1154 return this->address() + offset;
1157 // Return the PLT address to use for a local symbol. These are always
1158 // IRELATIVE relocs.
1161 Output_data_plt_i386::address_for_local(const Relobj*, unsigned int)
1163 return this->address() + (this->count_ + 1) * this->get_plt_entry_size();
1166 // The first entry in the PLT for an executable.
1168 const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] =
1170 0xff, 0x35, // pushl contents of memory address
1171 0, 0, 0, 0, // replaced with address of .got + 4
1172 0xff, 0x25, // jmp indirect
1173 0, 0, 0, 0, // replaced with address of .got + 8
1174 0, 0, 0, 0 // unused
1178 Output_data_plt_i386_exec::do_fill_first_plt_entry(
1180 elfcpp::Elf_types<32>::Elf_Addr got_address)
1182 memcpy(pov, first_plt_entry, plt_entry_size);
1183 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
1184 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
1187 // The first entry in the PLT for a shared object.
1189 const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] =
1191 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
1192 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
1193 0, 0, 0, 0 // unused
1197 Output_data_plt_i386_dyn::do_fill_first_plt_entry(
1199 elfcpp::Elf_types<32>::Elf_Addr)
1201 memcpy(pov, first_plt_entry, plt_entry_size);
1204 // Subsequent entries in the PLT for an executable.
1206 const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] =
1208 0xff, 0x25, // jmp indirect
1209 0, 0, 0, 0, // replaced with address of symbol in .got
1210 0x68, // pushl immediate
1211 0, 0, 0, 0, // replaced with offset into relocation table
1212 0xe9, // jmp relative
1213 0, 0, 0, 0 // replaced with offset to start of .plt
1217 Output_data_plt_i386_exec::do_fill_plt_entry(
1219 elfcpp::Elf_types<32>::Elf_Addr got_address,
1220 unsigned int got_offset,
1221 unsigned int plt_offset,
1222 unsigned int plt_rel_offset)
1224 memcpy(pov, plt_entry, plt_entry_size);
1225 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1226 got_address + got_offset);
1227 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1228 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1232 // Subsequent entries in the PLT for a shared object.
1234 const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] =
1236 0xff, 0xa3, // jmp *offset(%ebx)
1237 0, 0, 0, 0, // replaced with offset of symbol in .got
1238 0x68, // pushl immediate
1239 0, 0, 0, 0, // replaced with offset into relocation table
1240 0xe9, // jmp relative
1241 0, 0, 0, 0 // replaced with offset to start of .plt
1245 Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov,
1246 elfcpp::Elf_types<32>::Elf_Addr,
1247 unsigned int got_offset,
1248 unsigned int plt_offset,
1249 unsigned int plt_rel_offset)
1251 memcpy(pov, plt_entry, plt_entry_size);
1252 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
1253 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
1254 elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4));
1258 // The .eh_frame unwind information for the PLT.
1261 Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1264 'z', // Augmentation: augmentation size included.
1265 'R', // Augmentation: FDE encoding included.
1266 '\0', // End of augmentation string.
1267 1, // Code alignment factor.
1268 0x7c, // Data alignment factor.
1269 8, // Return address column.
1270 1, // Augmentation size.
1271 (elfcpp::DW_EH_PE_pcrel // FDE encoding.
1272 | elfcpp::DW_EH_PE_sdata4),
1273 elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
1274 elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
1275 elfcpp::DW_CFA_nop, // Align to 16 bytes.
1280 Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1282 0, 0, 0, 0, // Replaced with offset to .plt.
1283 0, 0, 0, 0, // Replaced with size of .plt.
1284 0, // Augmentation size.
1285 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
1286 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
1287 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
1288 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
1289 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
1290 11, // Block length.
1291 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
1292 elfcpp::DW_OP_breg8, 0, // Push %eip.
1293 elfcpp::DW_OP_lit15, // Push 0xf.
1294 elfcpp::DW_OP_and, // & (%eip & 0xf).
1295 elfcpp::DW_OP_lit11, // Push 0xb.
1296 elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
1297 elfcpp::DW_OP_lit2, // Push 2.
1298 elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
1299 elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4
1300 elfcpp::DW_CFA_nop, // Align to 32 bytes.
1306 // Write out the PLT. This uses the hand-coded instructions above,
1307 // and adjusts them as needed. This is all specified by the i386 ELF
1308 // Processor Supplement.
1311 Output_data_plt_i386::do_write(Output_file* of)
1313 const off_t offset = this->offset();
1314 const section_size_type oview_size =
1315 convert_to_section_size_type(this->data_size());
1316 unsigned char* const oview = of->get_output_view(offset, oview_size);
1318 const off_t got_file_offset = this->got_plt_->offset();
1319 gold_assert(parameters->incremental_update()
1320 || (got_file_offset + this->got_plt_->data_size()
1321 == this->got_irelative_->offset()));
1322 const section_size_type got_size =
1323 convert_to_section_size_type(this->got_plt_->data_size()
1324 + this->got_irelative_->data_size());
1325 unsigned char* const got_view = of->get_output_view(got_file_offset,
1328 unsigned char* pov = oview;
1330 elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
1331 elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
1333 this->fill_first_plt_entry(pov, got_address);
1334 pov += this->get_plt_entry_size();
1336 unsigned char* got_pov = got_view;
1338 // The first entry in the GOT is the address of the .dynamic section
1339 // aka the PT_DYNAMIC segment. The next two entries are reserved.
1340 // We saved space for them when we created the section in
1341 // Target_i386::got_section.
1342 Output_section* dynamic = this->layout_->dynamic_section();
1343 uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1344 elfcpp::Swap<32, false>::writeval(got_pov, dynamic_addr);
1346 memset(got_pov, 0, 8);
1349 const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
1351 unsigned int plt_offset = this->get_plt_entry_size();
1352 unsigned int plt_rel_offset = 0;
1353 unsigned int got_offset = 12;
1354 const unsigned int count = this->count_ + this->irelative_count_;
1355 for (unsigned int i = 0;
1358 pov += this->get_plt_entry_size(),
1360 plt_offset += this->get_plt_entry_size(),
1361 plt_rel_offset += rel_size,
1364 // Set and adjust the PLT entry itself.
1365 unsigned int lazy_offset = this->fill_plt_entry(pov,
1371 // Set the entry in the GOT.
1372 elfcpp::Swap<32, false>::writeval(got_pov,
1373 plt_address + plt_offset + lazy_offset);
1376 // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
1377 // the GOT to point to the actual symbol value, rather than point to
1378 // the PLT entry. That will let the dynamic linker call the right
1379 // function when resolving IRELATIVE relocations.
1380 unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
1381 for (std::vector<Global_ifunc>::const_iterator p =
1382 this->global_ifuncs_.begin();
1383 p != this->global_ifuncs_.end();
1386 const Sized_symbol<32>* ssym =
1387 static_cast<const Sized_symbol<32>*>(p->sym);
1388 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1392 for (std::vector<Local_ifunc>::const_iterator p =
1393 this->local_ifuncs_.begin();
1394 p != this->local_ifuncs_.end();
1397 const Symbol_value<32>* psymval =
1398 p->object->local_symbol(p->local_sym_index);
1399 elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
1400 psymval->value(p->object, 0));
1403 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1404 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1406 of->write_output_view(offset, oview_size, oview);
1407 of->write_output_view(got_file_offset, got_size, got_view);
1410 // Create the PLT section.
1413 Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
1415 if (this->plt_ == NULL)
1417 // Create the GOT sections first.
1418 this->got_section(symtab, layout);
1420 const bool dyn = parameters->options().output_is_position_independent();
1421 this->plt_ = this->make_data_plt(layout,
1423 this->got_irelative_,
1426 // Add unwind information if requested.
1427 if (parameters->options().ld_generated_unwind_info())
1428 this->plt_->add_eh_frame(layout);
1430 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1432 | elfcpp::SHF_EXECINSTR),
1433 this->plt_, ORDER_PLT, false);
1435 // Make the sh_info field of .rel.plt point to .plt.
1436 Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
1437 rel_plt_os->set_info_section(this->plt_->output_section());
1441 // Create a PLT entry for a global symbol.
1444 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
1446 if (gsym->has_plt_offset())
1448 if (this->plt_ == NULL)
1449 this->make_plt_section(symtab, layout);
1450 this->plt_->add_entry(symtab, layout, gsym);
1453 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1456 Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1457 Sized_relobj_file<32, false>* relobj,
1458 unsigned int local_sym_index)
1460 if (relobj->local_has_plt_offset(local_sym_index))
1462 if (this->plt_ == NULL)
1463 this->make_plt_section(symtab, layout);
1464 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1467 relobj->set_local_plt_offset(local_sym_index, plt_offset);
1470 // Return the number of entries in the PLT.
1473 Target_i386::plt_entry_count() const
1475 if (this->plt_ == NULL)
1477 return this->plt_->entry_count();
1480 // Return the offset of the first non-reserved PLT entry.
1483 Target_i386::first_plt_entry_offset() const
1485 return this->plt_->first_plt_entry_offset();
1488 // Return the size of each PLT entry.
1491 Target_i386::plt_entry_size() const
1493 return this->plt_->get_plt_entry_size();
1496 // Get the section to use for TLS_DESC relocations.
1498 Target_i386::Reloc_section*
1499 Target_i386::rel_tls_desc_section(Layout* layout) const
1501 return this->plt_section()->rel_tls_desc(layout);
1504 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1507 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1509 if (this->tls_base_symbol_defined_)
1512 Output_segment* tls_segment = layout->tls_segment();
1513 if (tls_segment != NULL)
1515 bool is_exec = parameters->options().output_is_executable();
1516 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1517 Symbol_table::PREDEFINED,
1521 elfcpp::STV_HIDDEN, 0,
1523 ? Symbol::SEGMENT_END
1524 : Symbol::SEGMENT_START),
1527 this->tls_base_symbol_defined_ = true;
1530 // Create a GOT entry for the TLS module index.
1533 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1534 Sized_relobj_file<32, false>* object)
1536 if (this->got_mod_index_offset_ == -1U)
1538 gold_assert(symtab != NULL && layout != NULL && object != NULL);
1539 Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1540 Output_data_got<32, false>* got = this->got_section(symtab, layout);
1541 unsigned int got_offset = got->add_constant(0);
1542 rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
1544 got->add_constant(0);
1545 this->got_mod_index_offset_ = got_offset;
1547 return this->got_mod_index_offset_;
1550 // Optimize the TLS relocation type based on what we know about the
1551 // symbol. IS_FINAL is true if the final address of this symbol is
1552 // known at link time.
1554 tls::Tls_optimization
1555 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
1557 // If we are generating a shared library, then we can't do anything
1559 if (parameters->options().shared())
1560 return tls::TLSOPT_NONE;
1564 case elfcpp::R_386_TLS_GD:
1565 case elfcpp::R_386_TLS_GOTDESC:
1566 case elfcpp::R_386_TLS_DESC_CALL:
1567 // These are General-Dynamic which permits fully general TLS
1568 // access. Since we know that we are generating an executable,
1569 // we can convert this to Initial-Exec. If we also know that
1570 // this is a local symbol, we can further switch to Local-Exec.
1572 return tls::TLSOPT_TO_LE;
1573 return tls::TLSOPT_TO_IE;
1575 case elfcpp::R_386_TLS_LDM:
1576 // This is Local-Dynamic, which refers to a local symbol in the
1577 // dynamic TLS block. Since we know that we generating an
1578 // executable, we can switch to Local-Exec.
1579 return tls::TLSOPT_TO_LE;
1581 case elfcpp::R_386_TLS_LDO_32:
1582 // Another type of Local-Dynamic relocation.
1583 return tls::TLSOPT_TO_LE;
1585 case elfcpp::R_386_TLS_IE:
1586 case elfcpp::R_386_TLS_GOTIE:
1587 case elfcpp::R_386_TLS_IE_32:
1588 // These are Initial-Exec relocs which get the thread offset
1589 // from the GOT. If we know that we are linking against the
1590 // local symbol, we can switch to Local-Exec, which links the
1591 // thread offset into the instruction.
1593 return tls::TLSOPT_TO_LE;
1594 return tls::TLSOPT_NONE;
1596 case elfcpp::R_386_TLS_LE:
1597 case elfcpp::R_386_TLS_LE_32:
1598 // When we already have Local-Exec, there is nothing further we
1600 return tls::TLSOPT_NONE;
1607 // Get the Reference_flags for a particular relocation.
1610 Target_i386::Scan::get_reference_flags(unsigned int r_type)
1614 case elfcpp::R_386_NONE:
1615 case elfcpp::R_386_GNU_VTINHERIT:
1616 case elfcpp::R_386_GNU_VTENTRY:
1617 case elfcpp::R_386_GOTPC:
1618 // No symbol reference.
1621 case elfcpp::R_386_32:
1622 case elfcpp::R_386_16:
1623 case elfcpp::R_386_8:
1624 return Symbol::ABSOLUTE_REF;
1626 case elfcpp::R_386_PC32:
1627 case elfcpp::R_386_PC16:
1628 case elfcpp::R_386_PC8:
1629 case elfcpp::R_386_GOTOFF:
1630 return Symbol::RELATIVE_REF;
1632 case elfcpp::R_386_PLT32:
1633 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1635 case elfcpp::R_386_GOT32:
1637 return Symbol::ABSOLUTE_REF;
1639 case elfcpp::R_386_TLS_GD: // Global-dynamic
1640 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1641 case elfcpp::R_386_TLS_DESC_CALL:
1642 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1643 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1644 case elfcpp::R_386_TLS_IE: // Initial-exec
1645 case elfcpp::R_386_TLS_IE_32:
1646 case elfcpp::R_386_TLS_GOTIE:
1647 case elfcpp::R_386_TLS_LE: // Local-exec
1648 case elfcpp::R_386_TLS_LE_32:
1649 return Symbol::TLS_REF;
1651 case elfcpp::R_386_COPY:
1652 case elfcpp::R_386_GLOB_DAT:
1653 case elfcpp::R_386_JUMP_SLOT:
1654 case elfcpp::R_386_RELATIVE:
1655 case elfcpp::R_386_IRELATIVE:
1656 case elfcpp::R_386_TLS_TPOFF:
1657 case elfcpp::R_386_TLS_DTPMOD32:
1658 case elfcpp::R_386_TLS_DTPOFF32:
1659 case elfcpp::R_386_TLS_TPOFF32:
1660 case elfcpp::R_386_TLS_DESC:
1661 case elfcpp::R_386_32PLT:
1662 case elfcpp::R_386_TLS_GD_32:
1663 case elfcpp::R_386_TLS_GD_PUSH:
1664 case elfcpp::R_386_TLS_GD_CALL:
1665 case elfcpp::R_386_TLS_GD_POP:
1666 case elfcpp::R_386_TLS_LDM_32:
1667 case elfcpp::R_386_TLS_LDM_PUSH:
1668 case elfcpp::R_386_TLS_LDM_CALL:
1669 case elfcpp::R_386_TLS_LDM_POP:
1670 case elfcpp::R_386_USED_BY_INTEL_200:
1672 // Not expected. We will give an error later.
1677 // Report an unsupported relocation against a local symbol.
1680 Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
1681 unsigned int r_type)
1683 gold_error(_("%s: unsupported reloc %u against local symbol"),
1684 object->name().c_str(), r_type);
1687 // Return whether we need to make a PLT entry for a relocation of a
1688 // given type against a STT_GNU_IFUNC symbol.
1691 Target_i386::Scan::reloc_needs_plt_for_ifunc(
1692 Sized_relobj_file<32, false>* object,
1693 unsigned int r_type)
1695 int flags = Scan::get_reference_flags(r_type);
1696 if (flags & Symbol::TLS_REF)
1697 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1698 object->name().c_str(), r_type);
1702 // Scan a relocation for a local symbol.
1705 Target_i386::Scan::local(Symbol_table* symtab,
1707 Target_i386* target,
1708 Sized_relobj_file<32, false>* object,
1709 unsigned int data_shndx,
1710 Output_section* output_section,
1711 const elfcpp::Rel<32, false>& reloc,
1712 unsigned int r_type,
1713 const elfcpp::Sym<32, false>& lsym)
1715 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1716 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1717 && this->reloc_needs_plt_for_ifunc(object, r_type))
1719 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1720 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1725 case elfcpp::R_386_NONE:
1726 case elfcpp::R_386_GNU_VTINHERIT:
1727 case elfcpp::R_386_GNU_VTENTRY:
1730 case elfcpp::R_386_32:
1731 // If building a shared library (or a position-independent
1732 // executable), we need to create a dynamic relocation for
1733 // this location. The relocation applied at link time will
1734 // apply the link-time value, so we flag the location with
1735 // an R_386_RELATIVE relocation so the dynamic loader can
1736 // relocate it easily.
1737 if (parameters->options().output_is_position_independent())
1739 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1740 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1741 rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
1742 output_section, data_shndx,
1743 reloc.get_r_offset());
1747 case elfcpp::R_386_16:
1748 case elfcpp::R_386_8:
1749 // If building a shared library (or a position-independent
1750 // executable), we need to create a dynamic relocation for
1751 // this location. Because the addend needs to remain in the
1752 // data section, we need to be careful not to apply this
1753 // relocation statically.
1754 if (parameters->options().output_is_position_independent())
1756 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1757 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1758 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1759 rel_dyn->add_local(object, r_sym, r_type, output_section,
1760 data_shndx, reloc.get_r_offset());
1763 gold_assert(lsym.get_st_value() == 0);
1764 unsigned int shndx = lsym.get_st_shndx();
1766 shndx = object->adjust_sym_shndx(r_sym, shndx,
1769 object->error(_("section symbol %u has bad shndx %u"),
1772 rel_dyn->add_local_section(object, shndx,
1773 r_type, output_section,
1774 data_shndx, reloc.get_r_offset());
1779 case elfcpp::R_386_PC32:
1780 case elfcpp::R_386_PC16:
1781 case elfcpp::R_386_PC8:
1784 case elfcpp::R_386_PLT32:
1785 // Since we know this is a local symbol, we can handle this as a
1789 case elfcpp::R_386_GOTOFF:
1790 case elfcpp::R_386_GOTPC:
1791 // We need a GOT section.
1792 target->got_section(symtab, layout);
1795 case elfcpp::R_386_GOT32:
1797 // The symbol requires a GOT entry.
1798 Output_data_got<32, false>* got = target->got_section(symtab, layout);
1799 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1801 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1802 // lets function pointers compare correctly with shared
1803 // libraries. Otherwise we would need an IRELATIVE reloc.
1805 if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1806 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1808 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1811 // If we are generating a shared object, we need to add a
1812 // dynamic RELATIVE relocation for this symbol's GOT entry.
1813 if (parameters->options().output_is_position_independent())
1815 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1816 unsigned int got_offset =
1817 object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1818 rel_dyn->add_local_relative(object, r_sym,
1819 elfcpp::R_386_RELATIVE,
1826 // These are relocations which should only be seen by the
1827 // dynamic linker, and should never be seen here.
1828 case elfcpp::R_386_COPY:
1829 case elfcpp::R_386_GLOB_DAT:
1830 case elfcpp::R_386_JUMP_SLOT:
1831 case elfcpp::R_386_RELATIVE:
1832 case elfcpp::R_386_IRELATIVE:
1833 case elfcpp::R_386_TLS_TPOFF:
1834 case elfcpp::R_386_TLS_DTPMOD32:
1835 case elfcpp::R_386_TLS_DTPOFF32:
1836 case elfcpp::R_386_TLS_TPOFF32:
1837 case elfcpp::R_386_TLS_DESC:
1838 gold_error(_("%s: unexpected reloc %u in object file"),
1839 object->name().c_str(), r_type);
1842 // These are initial TLS relocs, which are expected when
1844 case elfcpp::R_386_TLS_GD: // Global-dynamic
1845 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
1846 case elfcpp::R_386_TLS_DESC_CALL:
1847 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1848 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1849 case elfcpp::R_386_TLS_IE: // Initial-exec
1850 case elfcpp::R_386_TLS_IE_32:
1851 case elfcpp::R_386_TLS_GOTIE:
1852 case elfcpp::R_386_TLS_LE: // Local-exec
1853 case elfcpp::R_386_TLS_LE_32:
1855 bool output_is_shared = parameters->options().shared();
1856 const tls::Tls_optimization optimized_type
1857 = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1860 case elfcpp::R_386_TLS_GD: // Global-dynamic
1861 if (optimized_type == tls::TLSOPT_NONE)
1863 // Create a pair of GOT entries for the module index and
1864 // dtv-relative offset.
1865 Output_data_got<32, false>* got
1866 = target->got_section(symtab, layout);
1867 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1868 unsigned int shndx = lsym.get_st_shndx();
1870 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1872 object->error(_("local symbol %u has bad shndx %u"),
1875 got->add_local_pair_with_rel(object, r_sym, shndx,
1877 target->rel_dyn_section(layout),
1878 elfcpp::R_386_TLS_DTPMOD32, 0);
1880 else if (optimized_type != tls::TLSOPT_TO_LE)
1881 unsupported_reloc_local(object, r_type);
1884 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
1885 target->define_tls_base_symbol(symtab, layout);
1886 if (optimized_type == tls::TLSOPT_NONE)
1888 // Create a double GOT entry with an R_386_TLS_DESC
1889 // reloc. The R_386_TLS_DESC reloc is resolved
1890 // lazily, so the GOT entry needs to be in an area in
1891 // .got.plt, not .got. Call got_section to make sure
1892 // the section has been created.
1893 target->got_section(symtab, layout);
1894 Output_data_got<32, false>* got = target->got_tlsdesc_section();
1895 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1896 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1898 unsigned int got_offset = got->add_constant(0);
1899 // The local symbol value is stored in the second
1901 got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1902 // That set the GOT offset of the local symbol to
1903 // point to the second entry, but we want it to
1904 // point to the first.
1905 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1907 Reloc_section* rt = target->rel_tls_desc_section(layout);
1908 rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1911 else if (optimized_type != tls::TLSOPT_TO_LE)
1912 unsupported_reloc_local(object, r_type);
1915 case elfcpp::R_386_TLS_DESC_CALL:
1918 case elfcpp::R_386_TLS_LDM: // Local-dynamic
1919 if (optimized_type == tls::TLSOPT_NONE)
1921 // Create a GOT entry for the module index.
1922 target->got_mod_index_entry(symtab, layout, object);
1924 else if (optimized_type != tls::TLSOPT_TO_LE)
1925 unsupported_reloc_local(object, r_type);
1928 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
1931 case elfcpp::R_386_TLS_IE: // Initial-exec
1932 case elfcpp::R_386_TLS_IE_32:
1933 case elfcpp::R_386_TLS_GOTIE:
1934 layout->set_has_static_tls();
1935 if (optimized_type == tls::TLSOPT_NONE)
1937 // For the R_386_TLS_IE relocation, we need to create a
1938 // dynamic relocation when building a shared library.
1939 if (r_type == elfcpp::R_386_TLS_IE
1940 && parameters->options().shared())
1942 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1944 = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1945 rel_dyn->add_local_relative(object, r_sym,
1946 elfcpp::R_386_RELATIVE,
1947 output_section, data_shndx,
1948 reloc.get_r_offset());
1950 // Create a GOT entry for the tp-relative offset.
1951 Output_data_got<32, false>* got
1952 = target->got_section(symtab, layout);
1953 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1954 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1955 ? elfcpp::R_386_TLS_TPOFF32
1956 : elfcpp::R_386_TLS_TPOFF);
1957 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1958 ? GOT_TYPE_TLS_OFFSET
1959 : GOT_TYPE_TLS_NOFFSET);
1960 got->add_local_with_rel(object, r_sym, got_type,
1961 target->rel_dyn_section(layout),
1964 else if (optimized_type != tls::TLSOPT_TO_LE)
1965 unsupported_reloc_local(object, r_type);
1968 case elfcpp::R_386_TLS_LE: // Local-exec
1969 case elfcpp::R_386_TLS_LE_32:
1970 layout->set_has_static_tls();
1971 if (output_is_shared)
1973 // We need to create a dynamic relocation.
1974 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1975 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1976 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1977 ? elfcpp::R_386_TLS_TPOFF32
1978 : elfcpp::R_386_TLS_TPOFF);
1979 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1980 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1981 data_shndx, reloc.get_r_offset());
1991 case elfcpp::R_386_32PLT:
1992 case elfcpp::R_386_TLS_GD_32:
1993 case elfcpp::R_386_TLS_GD_PUSH:
1994 case elfcpp::R_386_TLS_GD_CALL:
1995 case elfcpp::R_386_TLS_GD_POP:
1996 case elfcpp::R_386_TLS_LDM_32:
1997 case elfcpp::R_386_TLS_LDM_PUSH:
1998 case elfcpp::R_386_TLS_LDM_CALL:
1999 case elfcpp::R_386_TLS_LDM_POP:
2000 case elfcpp::R_386_USED_BY_INTEL_200:
2002 unsupported_reloc_local(object, r_type);
2007 // Report an unsupported relocation against a global symbol.
2010 Target_i386::Scan::unsupported_reloc_global(
2011 Sized_relobj_file<32, false>* object,
2012 unsigned int r_type,
2015 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2016 object->name().c_str(), r_type, gsym->demangled_name().c_str());
2020 Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
2024 case elfcpp::R_386_32:
2025 case elfcpp::R_386_16:
2026 case elfcpp::R_386_8:
2027 case elfcpp::R_386_GOTOFF:
2028 case elfcpp::R_386_GOT32:
2039 Target_i386::Scan::local_reloc_may_be_function_pointer(
2043 Sized_relobj_file<32, false>* ,
2046 const elfcpp::Rel<32, false>& ,
2047 unsigned int r_type,
2048 const elfcpp::Sym<32, false>&)
2050 return possible_function_pointer_reloc(r_type);
2054 Target_i386::Scan::global_reloc_may_be_function_pointer(
2058 Sized_relobj_file<32, false>* ,
2061 const elfcpp::Rel<32, false>& ,
2062 unsigned int r_type,
2065 return possible_function_pointer_reloc(r_type);
2068 // Scan a relocation for a global symbol.
2071 Target_i386::Scan::global(Symbol_table* symtab,
2073 Target_i386* target,
2074 Sized_relobj_file<32, false>* object,
2075 unsigned int data_shndx,
2076 Output_section* output_section,
2077 const elfcpp::Rel<32, false>& reloc,
2078 unsigned int r_type,
2081 // A STT_GNU_IFUNC symbol may require a PLT entry.
2082 if (gsym->type() == elfcpp::STT_GNU_IFUNC
2083 && this->reloc_needs_plt_for_ifunc(object, r_type))
2084 target->make_plt_entry(symtab, layout, gsym);
2088 case elfcpp::R_386_NONE:
2089 case elfcpp::R_386_GNU_VTINHERIT:
2090 case elfcpp::R_386_GNU_VTENTRY:
2093 case elfcpp::R_386_32:
2094 case elfcpp::R_386_16:
2095 case elfcpp::R_386_8:
2097 // Make a PLT entry if necessary.
2098 if (gsym->needs_plt_entry())
2100 target->make_plt_entry(symtab, layout, gsym);
2101 // Since this is not a PC-relative relocation, we may be
2102 // taking the address of a function. In that case we need to
2103 // set the entry in the dynamic symbol table to the address of
2105 if (gsym->is_from_dynobj() && !parameters->options().shared())
2106 gsym->set_needs_dynsym_value();
2108 // Make a dynamic relocation if necessary.
2109 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2111 if (gsym->may_need_copy_reloc())
2113 target->copy_reloc(symtab, layout, object,
2114 data_shndx, output_section, gsym, reloc);
2116 else if (r_type == elfcpp::R_386_32
2117 && gsym->type() == elfcpp::STT_GNU_IFUNC
2118 && gsym->can_use_relative_reloc(false)
2119 && !gsym->is_from_dynobj()
2120 && !gsym->is_undefined()
2121 && !gsym->is_preemptible())
2123 // Use an IRELATIVE reloc for a locally defined
2124 // STT_GNU_IFUNC symbol. This makes a function
2125 // address in a PIE executable match the address in a
2126 // shared library that it links against.
2127 Reloc_section* rel_dyn = target->rel_irelative_section(layout);
2128 rel_dyn->add_symbolless_global_addend(gsym,
2129 elfcpp::R_386_IRELATIVE,
2132 reloc.get_r_offset());
2134 else if (r_type == elfcpp::R_386_32
2135 && gsym->can_use_relative_reloc(false))
2137 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2138 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2139 output_section, object,
2140 data_shndx, reloc.get_r_offset());
2144 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2145 rel_dyn->add_global(gsym, r_type, output_section, object,
2146 data_shndx, reloc.get_r_offset());
2152 case elfcpp::R_386_PC32:
2153 case elfcpp::R_386_PC16:
2154 case elfcpp::R_386_PC8:
2156 // Make a PLT entry if necessary.
2157 if (gsym->needs_plt_entry())
2159 // These relocations are used for function calls only in
2160 // non-PIC code. For a 32-bit relocation in a shared library,
2161 // we'll need a text relocation anyway, so we can skip the
2162 // PLT entry and let the dynamic linker bind the call directly
2163 // to the target. For smaller relocations, we should use a
2164 // PLT entry to ensure that the call can reach.
2165 if (!parameters->options().shared()
2166 || r_type != elfcpp::R_386_PC32)
2167 target->make_plt_entry(symtab, layout, gsym);
2169 // Make a dynamic relocation if necessary.
2170 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2172 if (gsym->may_need_copy_reloc())
2174 target->copy_reloc(symtab, layout, object,
2175 data_shndx, output_section, gsym, reloc);
2179 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2180 rel_dyn->add_global(gsym, r_type, output_section, object,
2181 data_shndx, reloc.get_r_offset());
2187 case elfcpp::R_386_GOT32:
2189 // The symbol requires a GOT entry.
2190 Output_data_got<32, false>* got = target->got_section(symtab, layout);
2191 if (gsym->final_value_is_known())
2193 // For a STT_GNU_IFUNC symbol we want the PLT address.
2194 if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2195 got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2197 got->add_global(gsym, GOT_TYPE_STANDARD);
2201 // If this symbol is not fully resolved, we need to add a
2202 // GOT entry with a dynamic relocation.
2203 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2205 // Use a GLOB_DAT rather than a RELATIVE reloc if:
2207 // 1) The symbol may be defined in some other module.
2209 // 2) We are building a shared library and this is a
2210 // protected symbol; using GLOB_DAT means that the dynamic
2211 // linker can use the address of the PLT in the main
2212 // executable when appropriate so that function address
2213 // comparisons work.
2215 // 3) This is a STT_GNU_IFUNC symbol in position dependent
2216 // code, again so that function address comparisons work.
2217 if (gsym->is_from_dynobj()
2218 || gsym->is_undefined()
2219 || gsym->is_preemptible()
2220 || (gsym->visibility() == elfcpp::STV_PROTECTED
2221 && parameters->options().shared())
2222 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2223 && parameters->options().output_is_position_independent()))
2224 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
2225 rel_dyn, elfcpp::R_386_GLOB_DAT);
2228 // For a STT_GNU_IFUNC symbol we want to write the PLT
2229 // offset into the GOT, so that function pointer
2230 // comparisons work correctly.
2232 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2233 is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2236 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2237 // Tell the dynamic linker to use the PLT address
2238 // when resolving relocations.
2239 if (gsym->is_from_dynobj()
2240 && !parameters->options().shared())
2241 gsym->set_needs_dynsym_value();
2245 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2246 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2254 case elfcpp::R_386_PLT32:
2255 // If the symbol is fully resolved, this is just a PC32 reloc.
2256 // Otherwise we need a PLT entry.
2257 if (gsym->final_value_is_known())
2259 // If building a shared library, we can also skip the PLT entry
2260 // if the symbol is defined in the output file and is protected
2262 if (gsym->is_defined()
2263 && !gsym->is_from_dynobj()
2264 && !gsym->is_preemptible())
2266 target->make_plt_entry(symtab, layout, gsym);
2269 case elfcpp::R_386_GOTOFF:
2270 case elfcpp::R_386_GOTPC:
2271 // We need a GOT section.
2272 target->got_section(symtab, layout);
2275 // These are relocations which should only be seen by the
2276 // dynamic linker, and should never be seen here.
2277 case elfcpp::R_386_COPY:
2278 case elfcpp::R_386_GLOB_DAT:
2279 case elfcpp::R_386_JUMP_SLOT:
2280 case elfcpp::R_386_RELATIVE:
2281 case elfcpp::R_386_IRELATIVE:
2282 case elfcpp::R_386_TLS_TPOFF:
2283 case elfcpp::R_386_TLS_DTPMOD32:
2284 case elfcpp::R_386_TLS_DTPOFF32:
2285 case elfcpp::R_386_TLS_TPOFF32:
2286 case elfcpp::R_386_TLS_DESC:
2287 gold_error(_("%s: unexpected reloc %u in object file"),
2288 object->name().c_str(), r_type);
2291 // These are initial tls relocs, which are expected when
2293 case elfcpp::R_386_TLS_GD: // Global-dynamic
2294 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2295 case elfcpp::R_386_TLS_DESC_CALL:
2296 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2297 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2298 case elfcpp::R_386_TLS_IE: // Initial-exec
2299 case elfcpp::R_386_TLS_IE_32:
2300 case elfcpp::R_386_TLS_GOTIE:
2301 case elfcpp::R_386_TLS_LE: // Local-exec
2302 case elfcpp::R_386_TLS_LE_32:
2304 const bool is_final = gsym->final_value_is_known();
2305 const tls::Tls_optimization optimized_type
2306 = Target_i386::optimize_tls_reloc(is_final, r_type);
2309 case elfcpp::R_386_TLS_GD: // Global-dynamic
2310 if (optimized_type == tls::TLSOPT_NONE)
2312 // Create a pair of GOT entries for the module index and
2313 // dtv-relative offset.
2314 Output_data_got<32, false>* got
2315 = target->got_section(symtab, layout);
2316 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2317 target->rel_dyn_section(layout),
2318 elfcpp::R_386_TLS_DTPMOD32,
2319 elfcpp::R_386_TLS_DTPOFF32);
2321 else if (optimized_type == tls::TLSOPT_TO_IE)
2323 // Create a GOT entry for the tp-relative offset.
2324 Output_data_got<32, false>* got
2325 = target->got_section(symtab, layout);
2326 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2327 target->rel_dyn_section(layout),
2328 elfcpp::R_386_TLS_TPOFF);
2330 else if (optimized_type != tls::TLSOPT_TO_LE)
2331 unsupported_reloc_global(object, r_type, gsym);
2334 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
2335 target->define_tls_base_symbol(symtab, layout);
2336 if (optimized_type == tls::TLSOPT_NONE)
2338 // Create a double GOT entry with an R_386_TLS_DESC
2339 // reloc. The R_386_TLS_DESC reloc is resolved
2340 // lazily, so the GOT entry needs to be in an area in
2341 // .got.plt, not .got. Call got_section to make sure
2342 // the section has been created.
2343 target->got_section(symtab, layout);
2344 Output_data_got<32, false>* got = target->got_tlsdesc_section();
2345 Reloc_section* rt = target->rel_tls_desc_section(layout);
2346 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2347 elfcpp::R_386_TLS_DESC, 0);
2349 else if (optimized_type == tls::TLSOPT_TO_IE)
2351 // Create a GOT entry for the tp-relative offset.
2352 Output_data_got<32, false>* got
2353 = target->got_section(symtab, layout);
2354 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
2355 target->rel_dyn_section(layout),
2356 elfcpp::R_386_TLS_TPOFF);
2358 else if (optimized_type != tls::TLSOPT_TO_LE)
2359 unsupported_reloc_global(object, r_type, gsym);
2362 case elfcpp::R_386_TLS_DESC_CALL:
2365 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2366 if (optimized_type == tls::TLSOPT_NONE)
2368 // Create a GOT entry for the module index.
2369 target->got_mod_index_entry(symtab, layout, object);
2371 else if (optimized_type != tls::TLSOPT_TO_LE)
2372 unsupported_reloc_global(object, r_type, gsym);
2375 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2378 case elfcpp::R_386_TLS_IE: // Initial-exec
2379 case elfcpp::R_386_TLS_IE_32:
2380 case elfcpp::R_386_TLS_GOTIE:
2381 layout->set_has_static_tls();
2382 if (optimized_type == tls::TLSOPT_NONE)
2384 // For the R_386_TLS_IE relocation, we need to create a
2385 // dynamic relocation when building a shared library.
2386 if (r_type == elfcpp::R_386_TLS_IE
2387 && parameters->options().shared())
2389 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2390 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
2391 output_section, object,
2393 reloc.get_r_offset());
2395 // Create a GOT entry for the tp-relative offset.
2396 Output_data_got<32, false>* got
2397 = target->got_section(symtab, layout);
2398 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
2399 ? elfcpp::R_386_TLS_TPOFF32
2400 : elfcpp::R_386_TLS_TPOFF);
2401 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2402 ? GOT_TYPE_TLS_OFFSET
2403 : GOT_TYPE_TLS_NOFFSET);
2404 got->add_global_with_rel(gsym, got_type,
2405 target->rel_dyn_section(layout),
2408 else if (optimized_type != tls::TLSOPT_TO_LE)
2409 unsupported_reloc_global(object, r_type, gsym);
2412 case elfcpp::R_386_TLS_LE: // Local-exec
2413 case elfcpp::R_386_TLS_LE_32:
2414 layout->set_has_static_tls();
2415 if (parameters->options().shared())
2417 // We need to create a dynamic relocation.
2418 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
2419 ? elfcpp::R_386_TLS_TPOFF32
2420 : elfcpp::R_386_TLS_TPOFF);
2421 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
2422 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
2423 data_shndx, reloc.get_r_offset());
2433 case elfcpp::R_386_32PLT:
2434 case elfcpp::R_386_TLS_GD_32:
2435 case elfcpp::R_386_TLS_GD_PUSH:
2436 case elfcpp::R_386_TLS_GD_CALL:
2437 case elfcpp::R_386_TLS_GD_POP:
2438 case elfcpp::R_386_TLS_LDM_32:
2439 case elfcpp::R_386_TLS_LDM_PUSH:
2440 case elfcpp::R_386_TLS_LDM_CALL:
2441 case elfcpp::R_386_TLS_LDM_POP:
2442 case elfcpp::R_386_USED_BY_INTEL_200:
2444 unsupported_reloc_global(object, r_type, gsym);
2449 // Process relocations for gc.
2452 Target_i386::gc_process_relocs(Symbol_table* symtab,
2454 Sized_relobj_file<32, false>* object,
2455 unsigned int data_shndx,
2457 const unsigned char* prelocs,
2459 Output_section* output_section,
2460 bool needs_special_offset_handling,
2461 size_t local_symbol_count,
2462 const unsigned char* plocal_symbols)
2464 gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2466 Target_i386::Relocatable_size_for_reloc>(
2475 needs_special_offset_handling,
2480 // Scan relocations for a section.
2483 Target_i386::scan_relocs(Symbol_table* symtab,
2485 Sized_relobj_file<32, false>* object,
2486 unsigned int data_shndx,
2487 unsigned int sh_type,
2488 const unsigned char* prelocs,
2490 Output_section* output_section,
2491 bool needs_special_offset_handling,
2492 size_t local_symbol_count,
2493 const unsigned char* plocal_symbols)
2495 if (sh_type == elfcpp::SHT_RELA)
2497 gold_error(_("%s: unsupported RELA reloc section"),
2498 object->name().c_str());
2502 gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
2512 needs_special_offset_handling,
2517 // Finalize the sections.
2520 Target_i386::do_finalize_sections(
2522 const Input_objects*,
2523 Symbol_table* symtab)
2525 const Reloc_section* rel_plt = (this->plt_ == NULL
2527 : this->plt_->rel_plt());
2528 layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
2529 this->rel_dyn_, true, false);
2531 // Emit any relocs we saved in an attempt to avoid generating COPY
2533 if (this->copy_relocs_.any_saved_relocs())
2534 this->copy_relocs_.emit(this->rel_dyn_section(layout));
2536 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2537 // the .got.plt section.
2538 Symbol* sym = this->global_offset_table_;
2541 uint32_t data_size = this->got_plt_->current_data_size();
2542 symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
2545 if (parameters->doing_static_link()
2546 && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2548 // If linking statically, make sure that the __rel_iplt symbols
2549 // were defined if necessary, even if we didn't create a PLT.
2550 static const Define_symbol_in_segment syms[] =
2553 "__rel_iplt_start", // name
2554 elfcpp::PT_LOAD, // segment_type
2555 elfcpp::PF_W, // segment_flags_set
2556 elfcpp::PF(0), // segment_flags_clear
2559 elfcpp::STT_NOTYPE, // type
2560 elfcpp::STB_GLOBAL, // binding
2561 elfcpp::STV_HIDDEN, // visibility
2563 Symbol::SEGMENT_START, // offset_from_base
2567 "__rel_iplt_end", // name
2568 elfcpp::PT_LOAD, // segment_type
2569 elfcpp::PF_W, // segment_flags_set
2570 elfcpp::PF(0), // segment_flags_clear
2573 elfcpp::STT_NOTYPE, // type
2574 elfcpp::STB_GLOBAL, // binding
2575 elfcpp::STV_HIDDEN, // visibility
2577 Symbol::SEGMENT_START, // offset_from_base
2582 symtab->define_symbols(layout, 2, syms,
2583 layout->script_options()->saw_sections_clause());
2587 // Return whether a direct absolute static relocation needs to be applied.
2588 // In cases where Scan::local() or Scan::global() has created
2589 // a dynamic relocation other than R_386_RELATIVE, the addend
2590 // of the relocation is carried in the data, and we must not
2591 // apply the static relocation.
2594 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
2595 unsigned int r_type,
2597 Output_section* output_section)
2599 // If the output section is not allocated, then we didn't call
2600 // scan_relocs, we didn't create a dynamic reloc, and we must apply
2602 if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
2605 int ref_flags = Scan::get_reference_flags(r_type);
2607 // For local symbols, we will have created a non-RELATIVE dynamic
2608 // relocation only if (a) the output is position independent,
2609 // (b) the relocation is absolute (not pc- or segment-relative), and
2610 // (c) the relocation is not 32 bits wide.
2612 return !(parameters->options().output_is_position_independent()
2613 && (ref_flags & Symbol::ABSOLUTE_REF)
2616 // For global symbols, we use the same helper routines used in the
2617 // scan pass. If we did not create a dynamic relocation, or if we
2618 // created a RELATIVE dynamic relocation, we should apply the static
2620 bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
2621 bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
2622 && gsym->can_use_relative_reloc(ref_flags
2623 & Symbol::FUNCTION_CALL);
2624 return !has_dyn || is_rel;
2627 // Perform a relocation.
2630 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
2631 Target_i386* target,
2632 Output_section* output_section,
2634 const elfcpp::Rel<32, false>& rel,
2635 unsigned int r_type,
2636 const Sized_symbol<32>* gsym,
2637 const Symbol_value<32>* psymval,
2638 unsigned char* view,
2639 elfcpp::Elf_types<32>::Elf_Addr address,
2640 section_size_type view_size)
2642 if (this->skip_call_tls_get_addr_)
2644 if ((r_type != elfcpp::R_386_PLT32
2645 && r_type != elfcpp::R_386_PC32)
2647 || strcmp(gsym->name(), "___tls_get_addr") != 0)
2648 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2649 _("missing expected TLS relocation"));
2652 this->skip_call_tls_get_addr_ = false;
2657 const Sized_relobj_file<32, false>* object = relinfo->object;
2659 // Pick the value to use for symbols defined in shared objects.
2660 Symbol_value<32> symval;
2662 && gsym->type() == elfcpp::STT_GNU_IFUNC
2663 && r_type == elfcpp::R_386_32
2664 && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
2665 && gsym->can_use_relative_reloc(false)
2666 && !gsym->is_from_dynobj()
2667 && !gsym->is_undefined()
2668 && !gsym->is_preemptible())
2670 // In this case we are generating a R_386_IRELATIVE reloc. We
2671 // want to use the real value of the symbol, not the PLT offset.
2673 else if (gsym != NULL
2674 && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2676 symval.set_output_value(target->plt_address_for_global(gsym)
2677 + gsym->plt_offset());
2680 else if (gsym == NULL && psymval->is_ifunc_symbol())
2682 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2683 if (object->local_has_plt_offset(r_sym))
2685 symval.set_output_value(target->plt_address_for_local(object, r_sym)
2686 + object->local_plt_offset(r_sym));
2691 // Get the GOT offset if needed.
2692 // The GOT pointer points to the end of the GOT section.
2693 // We need to subtract the size of the GOT section to get
2694 // the actual offset to use in the relocation.
2695 bool have_got_offset = false;
2696 unsigned int got_offset = 0;
2699 case elfcpp::R_386_GOT32:
2702 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2703 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
2704 - target->got_size());
2708 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2709 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2710 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2711 - target->got_size());
2713 have_got_offset = true;
2722 case elfcpp::R_386_NONE:
2723 case elfcpp::R_386_GNU_VTINHERIT:
2724 case elfcpp::R_386_GNU_VTENTRY:
2727 case elfcpp::R_386_32:
2728 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2729 Relocate_functions<32, false>::rel32(view, object, psymval);
2732 case elfcpp::R_386_PC32:
2733 if (should_apply_static_reloc(gsym, r_type, true, output_section))
2734 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2737 case elfcpp::R_386_16:
2738 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2739 Relocate_functions<32, false>::rel16(view, object, psymval);
2742 case elfcpp::R_386_PC16:
2743 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2744 Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
2747 case elfcpp::R_386_8:
2748 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2749 Relocate_functions<32, false>::rel8(view, object, psymval);
2752 case elfcpp::R_386_PC8:
2753 if (should_apply_static_reloc(gsym, r_type, false, output_section))
2754 Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
2757 case elfcpp::R_386_PLT32:
2758 gold_assert(gsym == NULL
2759 || gsym->has_plt_offset()
2760 || gsym->final_value_is_known()
2761 || (gsym->is_defined()
2762 && !gsym->is_from_dynobj()
2763 && !gsym->is_preemptible()));
2764 Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
2767 case elfcpp::R_386_GOT32:
2768 gold_assert(have_got_offset);
2769 Relocate_functions<32, false>::rel32(view, got_offset);
2772 case elfcpp::R_386_GOTOFF:
2774 elfcpp::Elf_types<32>::Elf_Addr value;
2775 value = (psymval->value(object, 0)
2776 - target->got_plt_section()->address());
2777 Relocate_functions<32, false>::rel32(view, value);
2781 case elfcpp::R_386_GOTPC:
2783 elfcpp::Elf_types<32>::Elf_Addr value;
2784 value = target->got_plt_section()->address();
2785 Relocate_functions<32, false>::pcrel32(view, value, address);
2789 case elfcpp::R_386_COPY:
2790 case elfcpp::R_386_GLOB_DAT:
2791 case elfcpp::R_386_JUMP_SLOT:
2792 case elfcpp::R_386_RELATIVE:
2793 case elfcpp::R_386_IRELATIVE:
2794 // These are outstanding tls relocs, which are unexpected when
2796 case elfcpp::R_386_TLS_TPOFF:
2797 case elfcpp::R_386_TLS_DTPMOD32:
2798 case elfcpp::R_386_TLS_DTPOFF32:
2799 case elfcpp::R_386_TLS_TPOFF32:
2800 case elfcpp::R_386_TLS_DESC:
2801 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2802 _("unexpected reloc %u in object file"),
2806 // These are initial tls relocs, which are expected when
2808 case elfcpp::R_386_TLS_GD: // Global-dynamic
2809 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2810 case elfcpp::R_386_TLS_DESC_CALL:
2811 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2812 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
2813 case elfcpp::R_386_TLS_IE: // Initial-exec
2814 case elfcpp::R_386_TLS_IE_32:
2815 case elfcpp::R_386_TLS_GOTIE:
2816 case elfcpp::R_386_TLS_LE: // Local-exec
2817 case elfcpp::R_386_TLS_LE_32:
2818 this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
2819 view, address, view_size);
2822 case elfcpp::R_386_32PLT:
2823 case elfcpp::R_386_TLS_GD_32:
2824 case elfcpp::R_386_TLS_GD_PUSH:
2825 case elfcpp::R_386_TLS_GD_CALL:
2826 case elfcpp::R_386_TLS_GD_POP:
2827 case elfcpp::R_386_TLS_LDM_32:
2828 case elfcpp::R_386_TLS_LDM_PUSH:
2829 case elfcpp::R_386_TLS_LDM_CALL:
2830 case elfcpp::R_386_TLS_LDM_POP:
2831 case elfcpp::R_386_USED_BY_INTEL_200:
2833 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2834 _("unsupported reloc %u"),
2842 // Perform a TLS relocation.
2845 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
2846 Target_i386* target,
2848 const elfcpp::Rel<32, false>& rel,
2849 unsigned int r_type,
2850 const Sized_symbol<32>* gsym,
2851 const Symbol_value<32>* psymval,
2852 unsigned char* view,
2853 elfcpp::Elf_types<32>::Elf_Addr,
2854 section_size_type view_size)
2856 Output_segment* tls_segment = relinfo->layout->tls_segment();
2858 const Sized_relobj_file<32, false>* object = relinfo->object;
2860 elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
2862 const bool is_final = (gsym == NULL
2863 ? !parameters->options().shared()
2864 : gsym->final_value_is_known());
2865 const tls::Tls_optimization optimized_type
2866 = Target_i386::optimize_tls_reloc(is_final, r_type);
2869 case elfcpp::R_386_TLS_GD: // Global-dynamic
2870 if (optimized_type == tls::TLSOPT_TO_LE)
2872 if (tls_segment == NULL)
2874 gold_assert(parameters->errors()->error_count() > 0
2875 || issue_undefined_symbol_error(gsym));
2878 this->tls_gd_to_le(relinfo, relnum, tls_segment,
2879 rel, r_type, value, view,
2885 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2886 ? GOT_TYPE_TLS_NOFFSET
2887 : GOT_TYPE_TLS_PAIR);
2888 unsigned int got_offset;
2891 gold_assert(gsym->has_got_offset(got_type));
2892 got_offset = gsym->got_offset(got_type) - target->got_size();
2896 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2897 gold_assert(object->local_has_got_offset(r_sym, got_type));
2898 got_offset = (object->local_got_offset(r_sym, got_type)
2899 - target->got_size());
2901 if (optimized_type == tls::TLSOPT_TO_IE)
2903 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2904 got_offset, view, view_size);
2907 else if (optimized_type == tls::TLSOPT_NONE)
2909 // Relocate the field with the offset of the pair of GOT
2911 Relocate_functions<32, false>::rel32(view, got_offset);
2915 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2916 _("unsupported reloc %u"),
2920 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
2921 case elfcpp::R_386_TLS_DESC_CALL:
2922 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2923 if (optimized_type == tls::TLSOPT_TO_LE)
2925 if (tls_segment == NULL)
2927 gold_assert(parameters->errors()->error_count() > 0
2928 || issue_undefined_symbol_error(gsym));
2931 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2932 rel, r_type, value, view,
2938 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2939 ? GOT_TYPE_TLS_NOFFSET
2940 : GOT_TYPE_TLS_DESC);
2941 unsigned int got_offset = 0;
2942 if (r_type == elfcpp::R_386_TLS_GOTDESC
2943 && optimized_type == tls::TLSOPT_NONE)
2945 // We created GOT entries in the .got.tlsdesc portion of
2946 // the .got.plt section, but the offset stored in the
2947 // symbol is the offset within .got.tlsdesc.
2948 got_offset = (target->got_size()
2949 + target->got_plt_section()->data_size());
2953 gold_assert(gsym->has_got_offset(got_type));
2954 got_offset += gsym->got_offset(got_type) - target->got_size();
2958 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2959 gold_assert(object->local_has_got_offset(r_sym, got_type));
2960 got_offset += (object->local_got_offset(r_sym, got_type)
2961 - target->got_size());
2963 if (optimized_type == tls::TLSOPT_TO_IE)
2965 if (tls_segment == NULL)
2967 gold_assert(parameters->errors()->error_count() > 0
2968 || issue_undefined_symbol_error(gsym));
2971 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
2972 got_offset, view, view_size);
2975 else if (optimized_type == tls::TLSOPT_NONE)
2977 if (r_type == elfcpp::R_386_TLS_GOTDESC)
2979 // Relocate the field with the offset of the pair of GOT
2981 Relocate_functions<32, false>::rel32(view, got_offset);
2986 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2987 _("unsupported reloc %u"),
2991 case elfcpp::R_386_TLS_LDM: // Local-dynamic
2992 if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
2994 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2995 _("both SUN and GNU model "
2996 "TLS relocations"));
2999 this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
3000 if (optimized_type == tls::TLSOPT_TO_LE)
3002 if (tls_segment == NULL)
3004 gold_assert(parameters->errors()->error_count() > 0
3005 || issue_undefined_symbol_error(gsym));
3008 this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
3009 value, view, view_size);
3012 else if (optimized_type == tls::TLSOPT_NONE)
3014 // Relocate the field with the offset of the GOT entry for
3015 // the module index.
3016 unsigned int got_offset;
3017 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3018 - target->got_size());
3019 Relocate_functions<32, false>::rel32(view, got_offset);
3022 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3023 _("unsupported reloc %u"),
3027 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3028 if (optimized_type == tls::TLSOPT_TO_LE)
3030 // This reloc can appear in debugging sections, in which
3031 // case we must not convert to local-exec. We decide what
3032 // to do based on whether the section is marked as
3033 // containing executable code. That is what the GNU linker
3035 elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
3036 if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
3038 if (tls_segment == NULL)
3040 gold_assert(parameters->errors()->error_count() > 0
3041 || issue_undefined_symbol_error(gsym));
3044 value -= tls_segment->memsz();
3047 Relocate_functions<32, false>::rel32(view, value);
3050 case elfcpp::R_386_TLS_IE: // Initial-exec
3051 case elfcpp::R_386_TLS_GOTIE:
3052 case elfcpp::R_386_TLS_IE_32:
3053 if (optimized_type == tls::TLSOPT_TO_LE)
3055 if (tls_segment == NULL)
3057 gold_assert(parameters->errors()->error_count() > 0
3058 || issue_undefined_symbol_error(gsym));
3061 Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
3062 rel, r_type, value, view,
3066 else if (optimized_type == tls::TLSOPT_NONE)
3068 // Relocate the field with the offset of the GOT entry for
3069 // the tp-relative offset of the symbol.
3070 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
3071 ? GOT_TYPE_TLS_OFFSET
3072 : GOT_TYPE_TLS_NOFFSET);
3073 unsigned int got_offset;
3076 gold_assert(gsym->has_got_offset(got_type));
3077 got_offset = gsym->got_offset(got_type);
3081 unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
3082 gold_assert(object->local_has_got_offset(r_sym, got_type));
3083 got_offset = object->local_got_offset(r_sym, got_type);
3085 // For the R_386_TLS_IE relocation, we need to apply the
3086 // absolute address of the GOT entry.
3087 if (r_type == elfcpp::R_386_TLS_IE)
3088 got_offset += target->got_plt_section()->address();
3089 // All GOT offsets are relative to the end of the GOT.
3090 got_offset -= target->got_size();
3091 Relocate_functions<32, false>::rel32(view, got_offset);
3094 gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
3095 _("unsupported reloc %u"),
3099 case elfcpp::R_386_TLS_LE: // Local-exec
3100 // If we're creating a shared library, a dynamic relocation will
3101 // have been created for this location, so do not apply it now.
3102 if (!parameters->options().shared())
3104 if (tls_segment == NULL)
3106 gold_assert(parameters->errors()->error_count() > 0
3107 || issue_undefined_symbol_error(gsym));
3110 value -= tls_segment->memsz();
3111 Relocate_functions<32, false>::rel32(view, value);
3115 case elfcpp::R_386_TLS_LE_32:
3116 // If we're creating a shared library, a dynamic relocation will
3117 // have been created for this location, so do not apply it now.
3118 if (!parameters->options().shared())
3120 if (tls_segment == NULL)
3122 gold_assert(parameters->errors()->error_count() > 0
3123 || issue_undefined_symbol_error(gsym));
3126 value = tls_segment->memsz() - value;
3127 Relocate_functions<32, false>::rel32(view, value);
3133 // Do a relocation in which we convert a TLS General-Dynamic to a
3137 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
3139 Output_segment* tls_segment,
3140 const elfcpp::Rel<32, false>& rel,
3142 elfcpp::Elf_types<32>::Elf_Addr value,
3143 unsigned char* view,
3144 section_size_type view_size)
3146 // leal foo(,%reg,1),%eax; call ___tls_get_addr
3147 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3148 // leal foo(%reg),%eax; call ___tls_get_addr
3149 // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
3151 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3152 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3154 unsigned char op1 = view[-1];
3155 unsigned char op2 = view[-2];
3157 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3158 op2 == 0x8d || op2 == 0x04);
3159 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3165 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3166 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3167 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3168 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3169 memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3173 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3174 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3175 if (rel.get_r_offset() + 9 < view_size
3178 // There is a trailing nop. Use the size byte subl.
3179 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3184 // Use the five byte subl.
3185 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3189 value = tls_segment->memsz() - value;
3190 Relocate_functions<32, false>::rel32(view + roff, value);
3192 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3194 this->skip_call_tls_get_addr_ = true;
3197 // Do a relocation in which we convert a TLS General-Dynamic to an
3201 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
3204 const elfcpp::Rel<32, false>& rel,
3206 elfcpp::Elf_types<32>::Elf_Addr value,
3207 unsigned char* view,
3208 section_size_type view_size)
3210 // leal foo(,%ebx,1),%eax; call ___tls_get_addr
3211 // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
3213 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3214 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3216 unsigned char op1 = view[-1];
3217 unsigned char op2 = view[-2];
3219 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3220 op2 == 0x8d || op2 == 0x04);
3221 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3225 // FIXME: For now, support only the first (SIB) form.
3226 tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
3230 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
3231 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
3232 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3233 ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
3234 memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
3238 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3239 (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
3240 if (rel.get_r_offset() + 9 < view_size
3243 // FIXME: This is not the right instruction sequence.
3244 // There is a trailing nop. Use the size byte subl.
3245 memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
3250 // FIXME: This is not the right instruction sequence.
3251 // Use the five byte subl.
3252 memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
3256 Relocate_functions<32, false>::rel32(view + roff, value);
3258 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3260 this->skip_call_tls_get_addr_ = true;
3263 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3264 // General-Dynamic to a Local-Exec.
3267 Target_i386::Relocate::tls_desc_gd_to_le(
3268 const Relocate_info<32, false>* relinfo,
3270 Output_segment* tls_segment,
3271 const elfcpp::Rel<32, false>& rel,
3272 unsigned int r_type,
3273 elfcpp::Elf_types<32>::Elf_Addr value,
3274 unsigned char* view,
3275 section_size_type view_size)
3277 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3279 // leal foo@TLSDESC(%ebx), %eax
3280 // ==> leal foo@NTPOFF, %eax
3281 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3282 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3283 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3284 view[-2] == 0x8d && view[-1] == 0x83);
3286 value -= tls_segment->memsz();
3287 Relocate_functions<32, false>::rel32(view, value);
3291 // call *foo@TLSCALL(%eax)
3293 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3294 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3295 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3296 view[0] == 0xff && view[1] == 0x10);
3302 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
3303 // General-Dynamic to an Initial-Exec.
3306 Target_i386::Relocate::tls_desc_gd_to_ie(
3307 const Relocate_info<32, false>* relinfo,
3310 const elfcpp::Rel<32, false>& rel,
3311 unsigned int r_type,
3312 elfcpp::Elf_types<32>::Elf_Addr value,
3313 unsigned char* view,
3314 section_size_type view_size)
3316 if (r_type == elfcpp::R_386_TLS_GOTDESC)
3318 // leal foo@TLSDESC(%ebx), %eax
3319 // ==> movl foo@GOTNTPOFF(%ebx), %eax
3320 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3321 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3322 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3323 view[-2] == 0x8d && view[-1] == 0x83);
3325 Relocate_functions<32, false>::rel32(view, value);
3329 // call *foo@TLSCALL(%eax)
3331 gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
3332 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
3333 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3334 view[0] == 0xff && view[1] == 0x10);
3340 // Do a relocation in which we convert a TLS Local-Dynamic to a
3344 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
3347 const elfcpp::Rel<32, false>& rel,
3349 elfcpp::Elf_types<32>::Elf_Addr,
3350 unsigned char* view,
3351 section_size_type view_size)
3353 // leal foo(%reg), %eax; call ___tls_get_addr
3354 // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
3356 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3357 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
3359 // FIXME: Does this test really always pass?
3360 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3361 view[-2] == 0x8d && view[-1] == 0x83);
3363 tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
3365 memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
3367 // The next reloc should be a PLT32 reloc against __tls_get_addr.
3369 this->skip_call_tls_get_addr_ = true;
3372 // Do a relocation in which we convert a TLS Initial-Exec to a
3376 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
3378 Output_segment* tls_segment,
3379 const elfcpp::Rel<32, false>& rel,
3380 unsigned int r_type,
3381 elfcpp::Elf_types<32>::Elf_Addr value,
3382 unsigned char* view,
3383 section_size_type view_size)
3385 // We have to actually change the instructions, which means that we
3386 // need to examine the opcodes to figure out which instruction we
3388 if (r_type == elfcpp::R_386_TLS_IE)
3390 // movl %gs:XX,%eax ==> movl $YY,%eax
3391 // movl %gs:XX,%reg ==> movl $YY,%reg
3392 // addl %gs:XX,%reg ==> addl $YY,%reg
3393 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
3394 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3396 unsigned char op1 = view[-1];
3399 // movl XX,%eax ==> movl $YY,%eax
3404 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3406 unsigned char op2 = view[-2];
3409 // movl XX,%reg ==> movl $YY,%reg
3410 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3411 (op1 & 0xc7) == 0x05);
3413 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3415 else if (op2 == 0x03)
3417 // addl XX,%reg ==> addl $YY,%reg
3418 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3419 (op1 & 0xc7) == 0x05);
3421 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3424 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3429 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3430 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3431 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3432 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
3433 tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
3435 unsigned char op1 = view[-1];
3436 unsigned char op2 = view[-2];
3437 tls::check_tls(relinfo, relnum, rel.get_r_offset(),
3438 (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
3441 // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
3443 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3445 else if (op2 == 0x2b)
3447 // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
3449 view[-1] = 0xe8 | ((op1 >> 3) & 7);
3451 else if (op2 == 0x03)
3453 // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
3455 view[-1] = 0xc0 | ((op1 >> 3) & 7);
3458 tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
3461 value = tls_segment->memsz() - value;
3462 if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
3465 Relocate_functions<32, false>::rel32(view, value);
3468 // Relocate section data.
3471 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
3472 unsigned int sh_type,
3473 const unsigned char* prelocs,
3475 Output_section* output_section,
3476 bool needs_special_offset_handling,
3477 unsigned char* view,
3478 elfcpp::Elf_types<32>::Elf_Addr address,
3479 section_size_type view_size,
3480 const Reloc_symbol_changes* reloc_symbol_changes)
3482 gold_assert(sh_type == elfcpp::SHT_REL);
3484 gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
3485 Target_i386::Relocate>(
3491 needs_special_offset_handling,
3495 reloc_symbol_changes);
3498 // Return the size of a relocation while scanning during a relocatable
3502 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
3503 unsigned int r_type,
3508 case elfcpp::R_386_NONE:
3509 case elfcpp::R_386_GNU_VTINHERIT:
3510 case elfcpp::R_386_GNU_VTENTRY:
3511 case elfcpp::R_386_TLS_GD: // Global-dynamic
3512 case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
3513 case elfcpp::R_386_TLS_DESC_CALL:
3514 case elfcpp::R_386_TLS_LDM: // Local-dynamic
3515 case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
3516 case elfcpp::R_386_TLS_IE: // Initial-exec
3517 case elfcpp::R_386_TLS_IE_32:
3518 case elfcpp::R_386_TLS_GOTIE:
3519 case elfcpp::R_386_TLS_LE: // Local-exec
3520 case elfcpp::R_386_TLS_LE_32:
3523 case elfcpp::R_386_32:
3524 case elfcpp::R_386_PC32:
3525 case elfcpp::R_386_GOT32:
3526 case elfcpp::R_386_PLT32:
3527 case elfcpp::R_386_GOTOFF:
3528 case elfcpp::R_386_GOTPC:
3531 case elfcpp::R_386_16:
3532 case elfcpp::R_386_PC16:
3535 case elfcpp::R_386_8:
3536 case elfcpp::R_386_PC8:
3539 // These are relocations which should only be seen by the
3540 // dynamic linker, and should never be seen here.
3541 case elfcpp::R_386_COPY:
3542 case elfcpp::R_386_GLOB_DAT:
3543 case elfcpp::R_386_JUMP_SLOT:
3544 case elfcpp::R_386_RELATIVE:
3545 case elfcpp::R_386_IRELATIVE:
3546 case elfcpp::R_386_TLS_TPOFF:
3547 case elfcpp::R_386_TLS_DTPMOD32:
3548 case elfcpp::R_386_TLS_DTPOFF32:
3549 case elfcpp::R_386_TLS_TPOFF32:
3550 case elfcpp::R_386_TLS_DESC:
3551 object->error(_("unexpected reloc %u in object file"), r_type);
3554 case elfcpp::R_386_32PLT:
3555 case elfcpp::R_386_TLS_GD_32:
3556 case elfcpp::R_386_TLS_GD_PUSH:
3557 case elfcpp::R_386_TLS_GD_CALL:
3558 case elfcpp::R_386_TLS_GD_POP:
3559 case elfcpp::R_386_TLS_LDM_32:
3560 case elfcpp::R_386_TLS_LDM_PUSH:
3561 case elfcpp::R_386_TLS_LDM_CALL:
3562 case elfcpp::R_386_TLS_LDM_POP:
3563 case elfcpp::R_386_USED_BY_INTEL_200:
3565 object->error(_("unsupported reloc %u in object file"), r_type);
3570 // Scan the relocs during a relocatable link.
3573 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
3575 Sized_relobj_file<32, false>* object,
3576 unsigned int data_shndx,
3577 unsigned int sh_type,
3578 const unsigned char* prelocs,
3580 Output_section* output_section,
3581 bool needs_special_offset_handling,
3582 size_t local_symbol_count,
3583 const unsigned char* plocal_symbols,
3584 Relocatable_relocs* rr)
3586 gold_assert(sh_type == elfcpp::SHT_REL);
3588 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
3589 Relocatable_size_for_reloc> Scan_relocatable_relocs;
3591 gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
3592 Scan_relocatable_relocs>(
3600 needs_special_offset_handling,
3606 // Relocate a section during a relocatable link.
3609 Target_i386::relocate_for_relocatable(
3610 const Relocate_info<32, false>* relinfo,
3611 unsigned int sh_type,
3612 const unsigned char* prelocs,
3614 Output_section* output_section,
3615 elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
3616 const Relocatable_relocs* rr,
3617 unsigned char* view,
3618 elfcpp::Elf_types<32>::Elf_Addr view_address,
3619 section_size_type view_size,
3620 unsigned char* reloc_view,
3621 section_size_type reloc_view_size)
3623 gold_assert(sh_type == elfcpp::SHT_REL);
3625 gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
3630 offset_in_output_section,
3639 // Return the value to use for a dynamic which requires special
3640 // treatment. This is how we support equality comparisons of function
3641 // pointers across shared library boundaries, as described in the
3642 // processor specific ABI supplement.
3645 Target_i386::do_dynsym_value(const Symbol* gsym) const
3647 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3648 return this->plt_address_for_global(gsym) + gsym->plt_offset();
3651 // Return a string used to fill a code section with nops to take up
3652 // the specified length.
3655 Target_i386::do_code_fill(section_size_type length) const
3659 // Build a jmp instruction to skip over the bytes.
3660 unsigned char jmp[5];
3662 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3663 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3664 + std::string(length - 5, static_cast<char>(0x90)));
3667 // Nop sequences of various lengths.
3668 const char nop1[1] = { '\x90' }; // nop
3669 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax
3670 const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi
3671 const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3673 const char nop5[5] = { '\x90', '\x8d', '\x74', // nop
3674 '\x26', '\x00' }; // leal 0(%esi,1),%esi
3675 const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3676 '\x00', '\x00', '\x00' };
3677 const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3678 '\x00', '\x00', '\x00',
3680 const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop
3681 '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi
3683 const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi
3684 '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi
3685 '\x00', '\x00', '\x00' };
3686 const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi
3687 '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi
3688 '\x00', '\x00', '\x00',
3690 const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi
3691 '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi
3692 '\x27', '\x00', '\x00',
3694 const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3695 '\x00', '\x00', '\x00', // leal 0L(%edi),%edi
3696 '\x8d', '\xbf', '\x00',
3697 '\x00', '\x00', '\x00' };
3698 const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi
3699 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3700 '\x8d', '\xbc', '\x27',
3701 '\x00', '\x00', '\x00',
3703 const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi
3704 '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi
3705 '\x00', '\x8d', '\xbc',
3706 '\x27', '\x00', '\x00',
3708 const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15
3709 '\x90', '\x90', '\x90', // nop,nop,nop,...
3710 '\x90', '\x90', '\x90',
3711 '\x90', '\x90', '\x90',
3712 '\x90', '\x90', '\x90' };
3714 const char* nops[16] = {
3716 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3717 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3720 return std::string(nops[length], length);
3723 // Return the value to use for the base of a DW_EH_PE_datarel offset
3724 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
3725 // assembler can not write out the difference between two labels in
3726 // different sections, so instead of using a pc-relative value they
3727 // use an offset from the GOT.
3730 Target_i386::do_ehframe_datarel_base() const
3732 gold_assert(this->global_offset_table_ != NULL);
3733 Symbol* sym = this->global_offset_table_;
3734 Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym);
3735 return ssym->value();
3738 // Return whether SYM should be treated as a call to a non-split
3739 // function. We don't want that to be true of a call to a
3740 // get_pc_thunk function.
3743 Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
3745 return (sym->type() == elfcpp::STT_FUNC
3746 && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
3749 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3750 // compiled with -fsplit-stack. The function calls non-split-stack
3751 // code. We have to change the function so that it always ensures
3752 // that it has enough stack space to run some random function.
3755 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
3756 section_offset_type fnoffset,
3757 section_size_type fnsize,
3758 unsigned char* view,
3759 section_size_type view_size,
3761 std::string* to) const
3763 // The function starts with a comparison of the stack pointer and a
3764 // field in the TCB. This is followed by a jump.
3767 if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
3770 // We will call __morestack if the carry flag is set after this
3771 // comparison. We turn the comparison into an stc instruction
3773 view[fnoffset] = '\xf9';
3774 this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
3776 // lea NN(%esp),%ecx
3777 // lea NN(%esp),%edx
3778 else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
3779 || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
3782 // This is loading an offset from the stack pointer for a
3783 // comparison. The offset is negative, so we decrease the
3784 // offset by the amount of space we need for the stack. This
3785 // means we will avoid calling __morestack if there happens to
3786 // be plenty of space on the stack already.
3787 unsigned char* pval = view + fnoffset + 3;
3788 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3789 val -= parameters->options().split_stack_adjust_size();
3790 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3794 if (!object->has_no_split_stack())
3795 object->error(_("failed to match split-stack sequence at "
3796 "section %u offset %0zx"),
3797 shndx, static_cast<size_t>(fnoffset));
3801 // We have to change the function so that it calls
3802 // __morestack_non_split instead of __morestack. The former will
3803 // allocate additional stack space.
3804 *from = "__morestack";
3805 *to = "__morestack_non_split";
3808 // The selector for i386 object files. Note this is never instantiated
3809 // directly. It's only used in Target_selector_i386_nacl, below.
3811 class Target_selector_i386 : public Target_selector_freebsd
3814 Target_selector_i386()
3815 : Target_selector_freebsd(elfcpp::EM_386, 32, false,
3816 "elf32-i386", "elf32-i386-freebsd",
3821 do_instantiate_target()
3822 { return new Target_i386(); }
3825 // NaCl variant. It uses different PLT contents.
3827 class Output_data_plt_i386_nacl : public Output_data_plt_i386
3830 Output_data_plt_i386_nacl(Layout* layout,
3831 Output_data_space* got_plt,
3832 Output_data_space* got_irelative)
3833 : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
3837 virtual unsigned int
3838 do_get_plt_entry_size() const
3839 { return plt_entry_size; }
3842 do_add_eh_frame(Layout* layout)
3844 layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
3845 plt_eh_frame_fde, plt_eh_frame_fde_size);
3848 // The size of an entry in the PLT.
3849 static const int plt_entry_size = 64;
3851 // The .eh_frame unwind information for the PLT.
3852 static const int plt_eh_frame_fde_size = 32;
3853 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
3856 class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl
3859 Output_data_plt_i386_nacl_exec(Layout* layout,
3860 Output_data_space* got_plt,
3861 Output_data_space* got_irelative)
3862 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
3867 do_fill_first_plt_entry(unsigned char* pov,
3868 elfcpp::Elf_types<32>::Elf_Addr got_address);
3870 virtual unsigned int
3871 do_fill_plt_entry(unsigned char* pov,
3872 elfcpp::Elf_types<32>::Elf_Addr got_address,
3873 unsigned int got_offset,
3874 unsigned int plt_offset,
3875 unsigned int plt_rel_offset);
3878 // The first entry in the PLT for an executable.
3879 static const unsigned char first_plt_entry[plt_entry_size];
3881 // Other entries in the PLT for an executable.
3882 static const unsigned char plt_entry[plt_entry_size];
3885 class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl
3888 Output_data_plt_i386_nacl_dyn(Layout* layout,
3889 Output_data_space* got_plt,
3890 Output_data_space* got_irelative)
3891 : Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
3896 do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
3898 virtual unsigned int
3899 do_fill_plt_entry(unsigned char* pov,
3900 elfcpp::Elf_types<32>::Elf_Addr,
3901 unsigned int got_offset,
3902 unsigned int plt_offset,
3903 unsigned int plt_rel_offset);
3906 // The first entry in the PLT for a shared object.
3907 static const unsigned char first_plt_entry[plt_entry_size];
3909 // Other entries in the PLT for a shared object.
3910 static const unsigned char plt_entry[plt_entry_size];
3913 class Target_i386_nacl : public Target_i386
3917 : Target_i386(&i386_nacl_info)
3921 virtual Output_data_plt_i386*
3922 do_make_data_plt(Layout* layout,
3923 Output_data_space* got_plt,
3924 Output_data_space* got_irelative,
3928 return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative);
3930 return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative);
3934 static const Target::Target_info i386_nacl_info;
3937 const Target::Target_info Target_i386_nacl::i386_nacl_info =
3940 false, // is_big_endian
3941 elfcpp::EM_386, // machine_code
3942 false, // has_make_symbol
3943 false, // has_resolve
3944 true, // has_code_fill
3945 true, // is_default_stack_executable
3946 true, // can_icf_inline_merge_sections
3948 "/lib/ld-nacl-x86-32.so.1", // dynamic_linker
3949 0x20000, // default_text_segment_address
3950 0x10000, // abi_pagesize (overridable by -z max-page-size)
3951 0x10000, // common_pagesize (overridable by -z common-page-size)
3952 true, // isolate_execinstr
3953 0x10000000, // rosegment_gap
3954 elfcpp::SHN_UNDEF, // small_common_shndx
3955 elfcpp::SHN_UNDEF, // large_common_shndx
3956 0, // small_common_section_flags
3957 0, // large_common_section_flags
3958 NULL, // attributes_section
3959 NULL // attributes_vendor
3962 #define NACLMASK 0xe0 // 32-byte alignment mask
3965 Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] =
3967 0xff, 0x35, // pushl contents of memory address
3968 0, 0, 0, 0, // replaced with address of .got + 4
3969 0x8b, 0x0d, // movl contents of address, %ecx
3970 0, 0, 0, 0, // replaced with address of .got + 8
3971 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
3972 0xff, 0xe1, // jmp *%ecx
3973 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3974 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3975 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3976 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3977 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3978 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3979 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops
3980 0x90, 0x90, 0x90, 0x90, 0x90
3984 Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry(
3986 elfcpp::Elf_types<32>::Elf_Addr got_address)
3988 memcpy(pov, first_plt_entry, plt_entry_size);
3989 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
3990 elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
3993 // The first entry in the PLT for a shared object.
3996 Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] =
3998 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
3999 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx
4000 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4001 0xff, 0xe1, // jmp *%ecx
4002 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4003 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4004 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4005 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4006 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4007 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4008 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4009 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4010 0x90, 0x90, 0x90, 0x90, 0x90, // nops
4011 0x90, 0x90, 0x90, 0x90, 0x90 // nops
4015 Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry(
4017 elfcpp::Elf_types<32>::Elf_Addr)
4019 memcpy(pov, first_plt_entry, plt_entry_size);
4022 // Subsequent entries in the PLT for an executable.
4025 Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] =
4027 0x8b, 0x0d, // movl contents of address, %ecx */
4028 0, 0, 0, 0, // replaced with address of symbol in .got
4029 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx
4030 0xff, 0xe1, // jmp *%ecx
4032 // Pad to the next 32-byte boundary with nop instructions.
4034 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4035 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4037 // Lazy GOT entries point here (32-byte aligned).
4038 0x68, // pushl immediate
4039 0, 0, 0, 0, // replaced with offset into relocation table
4040 0xe9, // jmp relative
4041 0, 0, 0, 0, // replaced with offset to start of .plt
4043 // Pad to the next 32-byte boundary with nop instructions.
4044 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4045 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4050 Output_data_plt_i386_nacl_exec::do_fill_plt_entry(
4052 elfcpp::Elf_types<32>::Elf_Addr got_address,
4053 unsigned int got_offset,
4054 unsigned int plt_offset,
4055 unsigned int plt_rel_offset)
4057 memcpy(pov, plt_entry, plt_entry_size);
4058 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
4059 got_address + got_offset);
4060 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4061 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4065 // Subsequent entries in the PLT for a shared object.
4068 Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] =
4070 0x8b, 0x8b, // movl offset(%ebx), %ecx
4071 0, 0, 0, 0, // replaced with offset of symbol in .got
4072 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx
4073 0xff, 0xe1, // jmp *%ecx
4075 // Pad to the next 32-byte boundary with nop instructions.
4077 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4078 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4080 // Lazy GOT entries point here (32-byte aligned).
4081 0x68, // pushl immediate
4082 0, 0, 0, 0, // replaced with offset into relocation table.
4083 0xe9, // jmp relative
4084 0, 0, 0, 0, // replaced with offset to start of .plt.
4086 // Pad to the next 32-byte boundary with nop instructions.
4087 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4088 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
4093 Output_data_plt_i386_nacl_dyn::do_fill_plt_entry(
4095 elfcpp::Elf_types<32>::Elf_Addr,
4096 unsigned int got_offset,
4097 unsigned int plt_offset,
4098 unsigned int plt_rel_offset)
4100 memcpy(pov, plt_entry, plt_entry_size);
4101 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
4102 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset);
4103 elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4));
4108 Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] =
4110 0, 0, 0, 0, // Replaced with offset to .plt.
4111 0, 0, 0, 0, // Replaced with size of .plt.
4112 0, // Augmentation size.
4113 elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8.
4114 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
4115 elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
4116 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64.
4117 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
4118 13, // Block length.
4119 elfcpp::DW_OP_breg4, 4, // Push %esp + 4.
4120 elfcpp::DW_OP_breg8, 0, // Push %eip.
4121 elfcpp::DW_OP_const1u, 63, // Push 0x3f.
4122 elfcpp::DW_OP_and, // & (%eip & 0x3f).
4123 elfcpp::DW_OP_const1u, 37, // Push 0x25.
4124 elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25)
4125 elfcpp::DW_OP_lit2, // Push 2.
4126 elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2)
4127 elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4
4128 elfcpp::DW_CFA_nop, // Align to 32 bytes.
4132 // The selector for i386-nacl object files.
4134 class Target_selector_i386_nacl
4135 : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl>
4138 Target_selector_i386_nacl()
4139 : Target_selector_nacl<Target_selector_i386,
4140 Target_i386_nacl>("x86-32",
4146 Target_selector_i386_nacl target_selector_i386;
4148 } // End anonymous namespace.