1 // x86_64.cc -- x86_64 target support for gold.
3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
28 #include "parameters.h"
35 #include "copy-relocs.h"
37 #include "target-reloc.h"
38 #include "target-select.h"
49 // A class to handle the PLT data.
51 class Output_data_plt_x86_64
: public Output_section_data
54 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
56 Output_data_plt_x86_64(Symbol_table
*, Layout
*, Output_data_got
<64, false>*,
59 // Add an entry to the PLT.
61 add_entry(Symbol
* gsym
);
63 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
65 add_local_ifunc_entry(Sized_relobj
<64, false>* relobj
,
66 unsigned int local_sym_index
);
68 // Add the reserved TLSDESC_PLT entry to the PLT.
70 reserve_tlsdesc_entry(unsigned int got_offset
)
71 { this->tlsdesc_got_offset_
= got_offset
; }
73 // Return true if a TLSDESC_PLT entry has been reserved.
75 has_tlsdesc_entry() const
76 { return this->tlsdesc_got_offset_
!= -1U; }
78 // Return the GOT offset for the reserved TLSDESC_PLT entry.
80 get_tlsdesc_got_offset() const
81 { return this->tlsdesc_got_offset_
; }
83 // Return the offset of the reserved TLSDESC_PLT entry.
85 get_tlsdesc_plt_offset() const
86 { return (this->count_
+ 1) * plt_entry_size
; }
88 // Return the .rela.plt section data.
91 { return this->rel_
; }
93 // Return where the TLSDESC relocations should go.
95 rela_tlsdesc(Layout
*);
97 // Return the number of PLT entries.
100 { return this->count_
; }
102 // Return the offset of the first non-reserved PLT entry.
104 first_plt_entry_offset()
105 { return plt_entry_size
; }
107 // Return the size of a PLT entry.
110 { return plt_entry_size
; }
114 do_adjust_output_section(Output_section
* os
);
116 // Write to a map file.
118 do_print_to_mapfile(Mapfile
* mapfile
) const
119 { mapfile
->print_output_data(this, _("** PLT")); }
122 // The size of an entry in the PLT.
123 static const int plt_entry_size
= 16;
125 // The first entry in the PLT.
126 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
127 // procedure linkage table for both programs and shared objects."
128 static unsigned char first_plt_entry
[plt_entry_size
];
130 // Other entries in the PLT for an executable.
131 static unsigned char plt_entry
[plt_entry_size
];
133 // The reserved TLSDESC entry in the PLT for an executable.
134 static unsigned char tlsdesc_plt_entry
[plt_entry_size
];
136 // Set the final size.
138 set_final_data_size();
140 // Write out the PLT data.
142 do_write(Output_file
*);
144 // The reloc section.
146 // The TLSDESC relocs, if necessary. These must follow the regular
148 Reloc_section
* tlsdesc_rel_
;
150 Output_data_got
<64, false>* got_
;
151 // The .got.plt section.
152 Output_data_space
* got_plt_
;
153 // The number of PLT entries.
155 // Offset of the reserved TLSDESC_GOT entry when needed.
156 unsigned int tlsdesc_got_offset_
;
159 // The x86_64 target class.
161 // http://www.x86-64.org/documentation/abi.pdf
162 // TLS info comes from
163 // http://people.redhat.com/drepper/tls.pdf
164 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
166 class Target_x86_64
: public Target_freebsd
<64, false>
169 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
170 // uses only Elf64_Rela relocation entries with explicit addends."
171 typedef Output_data_reloc
<elfcpp::SHT_RELA
, true, 64, false> Reloc_section
;
174 : Target_freebsd
<64, false>(&x86_64_info
),
175 got_(NULL
), plt_(NULL
), got_plt_(NULL
), got_tlsdesc_(NULL
),
176 global_offset_table_(NULL
), rela_dyn_(NULL
),
177 copy_relocs_(elfcpp::R_X86_64_COPY
), dynbss_(NULL
),
178 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
179 tls_base_symbol_defined_(false)
182 // This function should be defined in targets that can use relocation
183 // types to determine (implemented in local_reloc_may_be_function_pointer
184 // and global_reloc_may_be_function_pointer)
185 // if a function's pointer is taken. ICF uses this in safe mode to only
186 // fold those functions whose pointer is defintely not taken. For x86_64
187 // pie binaries, safe ICF cannot be done by looking at relocation types.
189 can_check_for_function_pointers() const
190 { return !parameters
->options().pie(); }
193 can_icf_inline_merge_sections () const
196 // Hook for a new output section.
198 do_new_output_section(Output_section
*) const;
200 // Scan the relocations to look for symbol adjustments.
202 gc_process_relocs(Symbol_table
* symtab
,
204 Sized_relobj
<64, false>* object
,
205 unsigned int data_shndx
,
206 unsigned int sh_type
,
207 const unsigned char* prelocs
,
209 Output_section
* output_section
,
210 bool needs_special_offset_handling
,
211 size_t local_symbol_count
,
212 const unsigned char* plocal_symbols
);
214 // Scan the relocations to look for symbol adjustments.
216 scan_relocs(Symbol_table
* symtab
,
218 Sized_relobj
<64, false>* object
,
219 unsigned int data_shndx
,
220 unsigned int sh_type
,
221 const unsigned char* prelocs
,
223 Output_section
* output_section
,
224 bool needs_special_offset_handling
,
225 size_t local_symbol_count
,
226 const unsigned char* plocal_symbols
);
228 // Finalize the sections.
230 do_finalize_sections(Layout
*, const Input_objects
*, Symbol_table
*);
232 // Return the value to use for a dynamic which requires special
235 do_dynsym_value(const Symbol
*) const;
237 // Relocate a section.
239 relocate_section(const Relocate_info
<64, false>*,
240 unsigned int sh_type
,
241 const unsigned char* prelocs
,
243 Output_section
* output_section
,
244 bool needs_special_offset_handling
,
246 elfcpp::Elf_types
<64>::Elf_Addr view_address
,
247 section_size_type view_size
,
248 const Reloc_symbol_changes
*);
250 // Scan the relocs during a relocatable link.
252 scan_relocatable_relocs(Symbol_table
* symtab
,
254 Sized_relobj
<64, false>* object
,
255 unsigned int data_shndx
,
256 unsigned int sh_type
,
257 const unsigned char* prelocs
,
259 Output_section
* output_section
,
260 bool needs_special_offset_handling
,
261 size_t local_symbol_count
,
262 const unsigned char* plocal_symbols
,
263 Relocatable_relocs
*);
265 // Relocate a section during a relocatable link.
267 relocate_for_relocatable(const Relocate_info
<64, false>*,
268 unsigned int sh_type
,
269 const unsigned char* prelocs
,
271 Output_section
* output_section
,
272 off_t offset_in_output_section
,
273 const Relocatable_relocs
*,
275 elfcpp::Elf_types
<64>::Elf_Addr view_address
,
276 section_size_type view_size
,
277 unsigned char* reloc_view
,
278 section_size_type reloc_view_size
);
280 // Return a string used to fill a code section with nops.
282 do_code_fill(section_size_type length
) const;
284 // Return whether SYM is defined by the ABI.
286 do_is_defined_by_abi(const Symbol
* sym
) const
287 { return strcmp(sym
->name(), "__tls_get_addr") == 0; }
289 // Return the symbol index to use for a target specific relocation.
290 // The only target specific relocation is R_X86_64_TLSDESC for a
291 // local symbol, which is an absolute reloc.
293 do_reloc_symbol_index(void*, unsigned int r_type
) const
295 gold_assert(r_type
== elfcpp::R_X86_64_TLSDESC
);
299 // Return the addend to use for a target specific relocation.
301 do_reloc_addend(void* arg
, unsigned int r_type
, uint64_t addend
) const;
303 // Return the PLT section.
305 do_plt_section_for_global(const Symbol
*) const
306 { return this->plt_section(); }
309 do_plt_section_for_local(const Relobj
*, unsigned int) const
310 { return this->plt_section(); }
312 // Adjust -fsplit-stack code which calls non-split-stack code.
314 do_calls_non_split(Relobj
* object
, unsigned int shndx
,
315 section_offset_type fnoffset
, section_size_type fnsize
,
316 unsigned char* view
, section_size_type view_size
,
317 std::string
* from
, std::string
* to
) const;
319 // Return the size of the GOT section.
323 gold_assert(this->got_
!= NULL
);
324 return this->got_
->data_size();
327 // Return the number of entries in the GOT.
329 got_entry_count() const
331 if (this->got_
== NULL
)
333 return this->got_size() / 8;
336 // Return the number of entries in the PLT.
338 plt_entry_count() const;
340 // Return the offset of the first non-reserved PLT entry.
342 first_plt_entry_offset() const;
344 // Return the size of each PLT entry.
346 plt_entry_size() const;
348 // Add a new reloc argument, returning the index in the vector.
350 add_tlsdesc_info(Sized_relobj
<64, false>* object
, unsigned int r_sym
)
352 this->tlsdesc_reloc_info_
.push_back(Tlsdesc_info(object
, r_sym
));
353 return this->tlsdesc_reloc_info_
.size() - 1;
357 // The class which scans relocations.
362 : issued_non_pic_error_(false)
366 get_reference_flags(unsigned int r_type
);
369 local(Symbol_table
* symtab
, Layout
* layout
, Target_x86_64
* target
,
370 Sized_relobj
<64, false>* object
,
371 unsigned int data_shndx
,
372 Output_section
* output_section
,
373 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
374 const elfcpp::Sym
<64, false>& lsym
);
377 global(Symbol_table
* symtab
, Layout
* layout
, Target_x86_64
* target
,
378 Sized_relobj
<64, false>* object
,
379 unsigned int data_shndx
,
380 Output_section
* output_section
,
381 const elfcpp::Rela
<64, false>& reloc
, unsigned int r_type
,
385 local_reloc_may_be_function_pointer(Symbol_table
* symtab
, Layout
* layout
,
386 Target_x86_64
* target
,
387 Sized_relobj
<64, false>* object
,
388 unsigned int data_shndx
,
389 Output_section
* output_section
,
390 const elfcpp::Rela
<64, false>& reloc
,
392 const elfcpp::Sym
<64, false>& lsym
);
395 global_reloc_may_be_function_pointer(Symbol_table
* symtab
, Layout
* layout
,
396 Target_x86_64
* target
,
397 Sized_relobj
<64, false>* object
,
398 unsigned int data_shndx
,
399 Output_section
* output_section
,
400 const elfcpp::Rela
<64, false>& reloc
,
406 unsupported_reloc_local(Sized_relobj
<64, false>*, unsigned int r_type
);
409 unsupported_reloc_global(Sized_relobj
<64, false>*, unsigned int r_type
,
413 check_non_pic(Relobj
*, unsigned int r_type
);
416 possible_function_pointer_reloc(unsigned int r_type
);
419 reloc_needs_plt_for_ifunc(Sized_relobj
<64, false>*, unsigned int r_type
);
421 // Whether we have issued an error about a non-PIC compilation.
422 bool issued_non_pic_error_
;
425 // The class which implements relocation.
430 : skip_call_tls_get_addr_(false)
435 if (this->skip_call_tls_get_addr_
)
437 // FIXME: This needs to specify the location somehow.
438 gold_error(_("missing expected TLS relocation"));
442 // Do a relocation. Return false if the caller should not issue
443 // any warnings about this relocation.
445 relocate(const Relocate_info
<64, false>*, Target_x86_64
*, Output_section
*,
446 size_t relnum
, const elfcpp::Rela
<64, false>&,
447 unsigned int r_type
, const Sized_symbol
<64>*,
448 const Symbol_value
<64>*,
449 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
,
453 // Do a TLS relocation.
455 relocate_tls(const Relocate_info
<64, false>*, Target_x86_64
*,
456 size_t relnum
, const elfcpp::Rela
<64, false>&,
457 unsigned int r_type
, const Sized_symbol
<64>*,
458 const Symbol_value
<64>*,
459 unsigned char*, elfcpp::Elf_types
<64>::Elf_Addr
,
462 // Do a TLS General-Dynamic to Initial-Exec transition.
464 tls_gd_to_ie(const Relocate_info
<64, false>*, size_t relnum
,
465 Output_segment
* tls_segment
,
466 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
467 elfcpp::Elf_types
<64>::Elf_Addr value
,
469 elfcpp::Elf_types
<64>::Elf_Addr
,
470 section_size_type view_size
);
472 // Do a TLS General-Dynamic to Local-Exec transition.
474 tls_gd_to_le(const Relocate_info
<64, false>*, size_t relnum
,
475 Output_segment
* tls_segment
,
476 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
477 elfcpp::Elf_types
<64>::Elf_Addr value
,
479 section_size_type view_size
);
481 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
483 tls_desc_gd_to_ie(const Relocate_info
<64, false>*, size_t relnum
,
484 Output_segment
* tls_segment
,
485 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
486 elfcpp::Elf_types
<64>::Elf_Addr value
,
488 elfcpp::Elf_types
<64>::Elf_Addr
,
489 section_size_type view_size
);
491 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
493 tls_desc_gd_to_le(const Relocate_info
<64, false>*, size_t relnum
,
494 Output_segment
* tls_segment
,
495 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
496 elfcpp::Elf_types
<64>::Elf_Addr value
,
498 section_size_type view_size
);
500 // Do a TLS Local-Dynamic to Local-Exec transition.
502 tls_ld_to_le(const Relocate_info
<64, false>*, size_t relnum
,
503 Output_segment
* tls_segment
,
504 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
505 elfcpp::Elf_types
<64>::Elf_Addr value
,
507 section_size_type view_size
);
509 // Do a TLS Initial-Exec to Local-Exec transition.
511 tls_ie_to_le(const Relocate_info
<64, false>*, size_t relnum
,
512 Output_segment
* tls_segment
,
513 const elfcpp::Rela
<64, false>&, unsigned int r_type
,
514 elfcpp::Elf_types
<64>::Elf_Addr value
,
516 section_size_type view_size
);
518 // This is set if we should skip the next reloc, which should be a
519 // PLT32 reloc against ___tls_get_addr.
520 bool skip_call_tls_get_addr_
;
523 // A class which returns the size required for a relocation type,
524 // used while scanning relocs during a relocatable link.
525 class Relocatable_size_for_reloc
529 get_size_for_reloc(unsigned int, Relobj
*);
532 // Adjust TLS relocation type based on the options and whether this
533 // is a local symbol.
534 static tls::Tls_optimization
535 optimize_tls_reloc(bool is_final
, int r_type
);
537 // Get the GOT section, creating it if necessary.
538 Output_data_got
<64, false>*
539 got_section(Symbol_table
*, Layout
*);
541 // Get the GOT PLT section.
543 got_plt_section() const
545 gold_assert(this->got_plt_
!= NULL
);
546 return this->got_plt_
;
549 // Get the GOT section for TLSDESC entries.
550 Output_data_got
<64, false>*
551 got_tlsdesc_section() const
553 gold_assert(this->got_tlsdesc_
!= NULL
);
554 return this->got_tlsdesc_
;
557 // Create the PLT section.
559 make_plt_section(Symbol_table
* symtab
, Layout
* layout
);
561 // Create a PLT entry for a global symbol.
563 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
565 // Create a PLT entry for a local STT_GNU_IFUNC symbol.
567 make_local_ifunc_plt_entry(Symbol_table
*, Layout
*,
568 Sized_relobj
<64, false>* relobj
,
569 unsigned int local_sym_index
);
571 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
573 define_tls_base_symbol(Symbol_table
*, Layout
*);
575 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
577 reserve_tlsdesc_entries(Symbol_table
* symtab
, Layout
* layout
);
579 // Create a GOT entry for the TLS module index.
581 got_mod_index_entry(Symbol_table
* symtab
, Layout
* layout
,
582 Sized_relobj
<64, false>* object
);
584 // Get the PLT section.
585 Output_data_plt_x86_64
*
588 gold_assert(this->plt_
!= NULL
);
592 // Get the dynamic reloc section, creating it if necessary.
594 rela_dyn_section(Layout
*);
596 // Get the section to use for TLSDESC relocations.
598 rela_tlsdesc_section(Layout
*) const;
600 // Add a potential copy relocation.
602 copy_reloc(Symbol_table
* symtab
, Layout
* layout
,
603 Sized_relobj
<64, false>* object
,
604 unsigned int shndx
, Output_section
* output_section
,
605 Symbol
* sym
, const elfcpp::Rela
<64, false>& reloc
)
607 this->copy_relocs_
.copy_reloc(symtab
, layout
,
608 symtab
->get_sized_symbol
<64>(sym
),
609 object
, shndx
, output_section
,
610 reloc
, this->rela_dyn_section(layout
));
613 // Information about this specific target which we pass to the
614 // general Target structure.
615 static const Target::Target_info x86_64_info
;
617 // The types of GOT entries needed for this platform.
618 // These values are exposed to the ABI in an incremental link.
619 // Do not renumber existing values without changing the version
620 // number of the .gnu_incremental_inputs section.
623 GOT_TYPE_STANDARD
= 0, // GOT entry for a regular symbol
624 GOT_TYPE_TLS_OFFSET
= 1, // GOT entry for TLS offset
625 GOT_TYPE_TLS_PAIR
= 2, // GOT entry for TLS module/offset pair
626 GOT_TYPE_TLS_DESC
= 3 // GOT entry for TLS_DESC pair
629 // This type is used as the argument to the target specific
630 // relocation routines. The only target specific reloc is
631 // R_X86_64_TLSDESC against a local symbol.
634 Tlsdesc_info(Sized_relobj
<64, false>* a_object
, unsigned int a_r_sym
)
635 : object(a_object
), r_sym(a_r_sym
)
638 // The object in which the local symbol is defined.
639 Sized_relobj
<64, false>* object
;
640 // The local symbol index in the object.
645 Output_data_got
<64, false>* got_
;
647 Output_data_plt_x86_64
* plt_
;
648 // The GOT PLT section.
649 Output_data_space
* got_plt_
;
650 // The GOT section for TLSDESC relocations.
651 Output_data_got
<64, false>* got_tlsdesc_
;
652 // The _GLOBAL_OFFSET_TABLE_ symbol.
653 Symbol
* global_offset_table_
;
654 // The dynamic reloc section.
655 Reloc_section
* rela_dyn_
;
656 // Relocs saved to avoid a COPY reloc.
657 Copy_relocs
<elfcpp::SHT_RELA
, 64, false> copy_relocs_
;
658 // Space for variables copied with a COPY reloc.
659 Output_data_space
* dynbss_
;
660 // Offset of the GOT entry for the TLS module index.
661 unsigned int got_mod_index_offset_
;
662 // We handle R_X86_64_TLSDESC against a local symbol as a target
663 // specific relocation. Here we store the object and local symbol
664 // index for the relocation.
665 std::vector
<Tlsdesc_info
> tlsdesc_reloc_info_
;
666 // True if the _TLS_MODULE_BASE_ symbol has been defined.
667 bool tls_base_symbol_defined_
;
670 const Target::Target_info
Target_x86_64::x86_64_info
=
673 false, // is_big_endian
674 elfcpp::EM_X86_64
, // machine_code
675 false, // has_make_symbol
676 false, // has_resolve
677 true, // has_code_fill
678 true, // is_default_stack_executable
680 "/lib/ld64.so.1", // program interpreter
681 0x400000, // default_text_segment_address
682 0x1000, // abi_pagesize (overridable by -z max-page-size)
683 0x1000, // common_pagesize (overridable by -z common-page-size)
684 elfcpp::SHN_UNDEF
, // small_common_shndx
685 elfcpp::SHN_X86_64_LCOMMON
, // large_common_shndx
686 0, // small_common_section_flags
687 elfcpp::SHF_X86_64_LARGE
, // large_common_section_flags
688 NULL
, // attributes_section
689 NULL
// attributes_vendor
692 // This is called when a new output section is created. This is where
693 // we handle the SHF_X86_64_LARGE.
696 Target_x86_64::do_new_output_section(Output_section
* os
) const
698 if ((os
->flags() & elfcpp::SHF_X86_64_LARGE
) != 0)
699 os
->set_is_large_section();
702 // Get the GOT section, creating it if necessary.
704 Output_data_got
<64, false>*
705 Target_x86_64::got_section(Symbol_table
* symtab
, Layout
* layout
)
707 if (this->got_
== NULL
)
709 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
711 this->got_
= new Output_data_got
<64, false>();
713 layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
715 | elfcpp::SHF_WRITE
),
716 this->got_
, ORDER_RELRO_LAST
,
719 this->got_plt_
= new Output_data_space(8, "** GOT PLT");
720 layout
->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS
,
722 | elfcpp::SHF_WRITE
),
723 this->got_plt_
, ORDER_NON_RELRO_FIRST
,
726 // The first three entries are reserved.
727 this->got_plt_
->set_current_data_size(3 * 8);
729 // Those bytes can go into the relro segment.
730 layout
->increase_relro(3 * 8);
732 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
733 this->global_offset_table_
=
734 symtab
->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL
,
735 Symbol_table::PREDEFINED
,
737 0, 0, elfcpp::STT_OBJECT
,
739 elfcpp::STV_HIDDEN
, 0,
742 // If there are any TLSDESC relocations, they get GOT entries in
743 // .got.plt after the jump slot entries.
744 this->got_tlsdesc_
= new Output_data_got
<64, false>();
745 layout
->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS
,
747 | elfcpp::SHF_WRITE
),
749 ORDER_NON_RELRO_FIRST
, false);
755 // Get the dynamic reloc section, creating it if necessary.
757 Target_x86_64::Reloc_section
*
758 Target_x86_64::rela_dyn_section(Layout
* layout
)
760 if (this->rela_dyn_
== NULL
)
762 gold_assert(layout
!= NULL
);
763 this->rela_dyn_
= new Reloc_section(parameters
->options().combreloc());
764 layout
->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA
,
765 elfcpp::SHF_ALLOC
, this->rela_dyn_
,
766 ORDER_DYNAMIC_RELOCS
, false);
768 return this->rela_dyn_
;
771 // Create the PLT section. The ordinary .got section is an argument,
772 // since we need to refer to the start. We also create our own .got
773 // section just for PLT entries.
775 Output_data_plt_x86_64::Output_data_plt_x86_64(Symbol_table
* symtab
,
777 Output_data_got
<64, false>* got
,
778 Output_data_space
* got_plt
)
779 : Output_section_data(8), tlsdesc_rel_(NULL
), got_(got
), got_plt_(got_plt
),
780 count_(0), tlsdesc_got_offset_(-1U)
782 this->rel_
= new Reloc_section(false);
783 layout
->add_output_section_data(".rela.plt", elfcpp::SHT_RELA
,
784 elfcpp::SHF_ALLOC
, this->rel_
,
785 ORDER_DYNAMIC_PLT_RELOCS
, false);
787 if (parameters
->doing_static_link())
789 // A statically linked executable will only have a .rela.plt
790 // section to hold R_X86_64_IRELATIVE relocs for STT_GNU_IFUNC
791 // symbols. The library will use these symbols to locate the
792 // IRELATIVE relocs at program startup time.
793 symtab
->define_in_output_data("__rela_iplt_start", NULL
,
794 Symbol_table::PREDEFINED
,
795 this->rel_
, 0, 0, elfcpp::STT_NOTYPE
,
796 elfcpp::STB_GLOBAL
, elfcpp::STV_HIDDEN
,
798 symtab
->define_in_output_data("__rela_iplt_end", NULL
,
799 Symbol_table::PREDEFINED
,
800 this->rel_
, 0, 0, elfcpp::STT_NOTYPE
,
801 elfcpp::STB_GLOBAL
, elfcpp::STV_HIDDEN
,
807 Output_data_plt_x86_64::do_adjust_output_section(Output_section
* os
)
809 os
->set_entsize(plt_entry_size
);
812 // Add an entry to the PLT.
815 Output_data_plt_x86_64::add_entry(Symbol
* gsym
)
817 gold_assert(!gsym
->has_plt_offset());
819 // Note that when setting the PLT offset we skip the initial
820 // reserved PLT entry.
821 gsym
->set_plt_offset((this->count_
+ 1) * plt_entry_size
);
825 section_offset_type got_offset
= this->got_plt_
->current_data_size();
827 // Every PLT entry needs a GOT entry which points back to the PLT
828 // entry (this will be changed by the dynamic linker, normally
829 // lazily when the function is called).
830 this->got_plt_
->set_current_data_size(got_offset
+ 8);
832 // Every PLT entry needs a reloc.
833 if (gsym
->type() == elfcpp::STT_GNU_IFUNC
834 && gsym
->can_use_relative_reloc(false))
835 this->rel_
->add_symbolless_global_addend(gsym
, elfcpp::R_X86_64_IRELATIVE
,
836 this->got_plt_
, got_offset
, 0);
839 gsym
->set_needs_dynsym_entry();
840 this->rel_
->add_global(gsym
, elfcpp::R_X86_64_JUMP_SLOT
, this->got_plt_
,
844 // Note that we don't need to save the symbol. The contents of the
845 // PLT are independent of which symbols are used. The symbols only
846 // appear in the relocations.
849 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
853 Output_data_plt_x86_64::add_local_ifunc_entry(Sized_relobj
<64, false>* relobj
,
854 unsigned int local_sym_index
)
856 unsigned int plt_offset
= (this->count_
+ 1) * plt_entry_size
;
859 section_offset_type got_offset
= this->got_plt_
->current_data_size();
861 // Every PLT entry needs a GOT entry which points back to the PLT
863 this->got_plt_
->set_current_data_size(got_offset
+ 8);
865 // Every PLT entry needs a reloc.
866 this->rel_
->add_symbolless_local_addend(relobj
, local_sym_index
,
867 elfcpp::R_X86_64_IRELATIVE
,
868 this->got_plt_
, got_offset
, 0);
873 // Return where the TLSDESC relocations should go, creating it if
874 // necessary. These follow the JUMP_SLOT relocations.
876 Output_data_plt_x86_64::Reloc_section
*
877 Output_data_plt_x86_64::rela_tlsdesc(Layout
* layout
)
879 if (this->tlsdesc_rel_
== NULL
)
881 this->tlsdesc_rel_
= new Reloc_section(false);
882 layout
->add_output_section_data(".rela.plt", elfcpp::SHT_RELA
,
883 elfcpp::SHF_ALLOC
, this->tlsdesc_rel_
,
884 ORDER_DYNAMIC_PLT_RELOCS
, false);
885 gold_assert(this->tlsdesc_rel_
->output_section() ==
886 this->rel_
->output_section());
888 return this->tlsdesc_rel_
;
891 // Set the final size.
893 Output_data_plt_x86_64::set_final_data_size()
895 unsigned int count
= this->count_
;
896 if (this->has_tlsdesc_entry())
898 this->set_data_size((count
+ 1) * plt_entry_size
);
901 // The first entry in the PLT for an executable.
903 unsigned char Output_data_plt_x86_64::first_plt_entry
[plt_entry_size
] =
905 // From AMD64 ABI Draft 0.98, page 76
906 0xff, 0x35, // pushq contents of memory address
907 0, 0, 0, 0, // replaced with address of .got + 8
908 0xff, 0x25, // jmp indirect
909 0, 0, 0, 0, // replaced with address of .got + 16
910 0x90, 0x90, 0x90, 0x90 // noop (x4)
913 // Subsequent entries in the PLT for an executable.
915 unsigned char Output_data_plt_x86_64::plt_entry
[plt_entry_size
] =
917 // From AMD64 ABI Draft 0.98, page 76
918 0xff, 0x25, // jmpq indirect
919 0, 0, 0, 0, // replaced with address of symbol in .got
920 0x68, // pushq immediate
921 0, 0, 0, 0, // replaced with offset into relocation table
922 0xe9, // jmpq relative
923 0, 0, 0, 0 // replaced with offset to start of .plt
926 // The reserved TLSDESC entry in the PLT for an executable.
928 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry
[plt_entry_size
] =
930 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
931 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
932 0xff, 0x35, // pushq x(%rip)
933 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
934 0xff, 0x25, // jmpq *y(%rip)
935 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
940 // Write out the PLT. This uses the hand-coded instructions above,
941 // and adjusts them as needed. This is specified by the AMD64 ABI.
944 Output_data_plt_x86_64::do_write(Output_file
* of
)
946 const off_t offset
= this->offset();
947 const section_size_type oview_size
=
948 convert_to_section_size_type(this->data_size());
949 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
951 const off_t got_file_offset
= this->got_plt_
->offset();
952 const section_size_type got_size
=
953 convert_to_section_size_type(this->got_plt_
->data_size());
954 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
957 unsigned char* pov
= oview
;
959 // The base address of the .plt section.
960 elfcpp::Elf_types
<64>::Elf_Addr plt_address
= this->address();
961 // The base address of the .got section.
962 elfcpp::Elf_types
<64>::Elf_Addr got_base
= this->got_
->address();
963 // The base address of the PLT portion of the .got section,
964 // which is where the GOT pointer will point, and where the
965 // three reserved GOT entries are located.
966 elfcpp::Elf_types
<64>::Elf_Addr got_address
= this->got_plt_
->address();
968 memcpy(pov
, first_plt_entry
, plt_entry_size
);
969 // We do a jmp relative to the PC at the end of this instruction.
970 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
972 - (plt_address
+ 6)));
973 elfcpp::Swap
<32, false>::writeval(pov
+ 8,
975 - (plt_address
+ 12)));
976 pov
+= plt_entry_size
;
978 unsigned char* got_pov
= got_view
;
980 memset(got_pov
, 0, 24);
983 unsigned int plt_offset
= plt_entry_size
;
984 unsigned int got_offset
= 24;
985 const unsigned int count
= this->count_
;
986 for (unsigned int plt_index
= 0;
989 pov
+= plt_entry_size
,
991 plt_offset
+= plt_entry_size
,
994 // Set and adjust the PLT entry itself.
995 memcpy(pov
, plt_entry
, plt_entry_size
);
996 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
997 (got_address
+ got_offset
998 - (plt_address
+ plt_offset
1001 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 7, plt_index
);
1002 elfcpp::Swap
<32, false>::writeval(pov
+ 12,
1003 - (plt_offset
+ plt_entry_size
));
1005 // Set the entry in the GOT.
1006 elfcpp::Swap
<64, false>::writeval(got_pov
, plt_address
+ plt_offset
+ 6);
1009 if (this->has_tlsdesc_entry())
1011 // Set and adjust the reserved TLSDESC PLT entry.
1012 unsigned int tlsdesc_got_offset
= this->get_tlsdesc_got_offset();
1013 memcpy(pov
, tlsdesc_plt_entry
, plt_entry_size
);
1014 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 2,
1016 - (plt_address
+ plt_offset
1018 elfcpp::Swap_unaligned
<32, false>::writeval(pov
+ 8,
1020 + tlsdesc_got_offset
1021 - (plt_address
+ plt_offset
1023 pov
+= plt_entry_size
;
1026 gold_assert(static_cast<section_size_type
>(pov
- oview
) == oview_size
);
1027 gold_assert(static_cast<section_size_type
>(got_pov
- got_view
) == got_size
);
1029 of
->write_output_view(offset
, oview_size
, oview
);
1030 of
->write_output_view(got_file_offset
, got_size
, got_view
);
1033 // Create the PLT section.
1036 Target_x86_64::make_plt_section(Symbol_table
* symtab
, Layout
* layout
)
1038 if (this->plt_
== NULL
)
1040 // Create the GOT sections first.
1041 this->got_section(symtab
, layout
);
1043 this->plt_
= new Output_data_plt_x86_64(symtab
, layout
, this->got_
,
1045 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
1047 | elfcpp::SHF_EXECINSTR
),
1048 this->plt_
, ORDER_PLT
, false);
1050 // Make the sh_info field of .rela.plt point to .plt.
1051 Output_section
* rela_plt_os
= this->plt_
->rela_plt()->output_section();
1052 rela_plt_os
->set_info_section(this->plt_
->output_section());
1056 // Return the section for TLSDESC relocations.
1058 Target_x86_64::Reloc_section
*
1059 Target_x86_64::rela_tlsdesc_section(Layout
* layout
) const
1061 return this->plt_section()->rela_tlsdesc(layout
);
1064 // Create a PLT entry for a global symbol.
1067 Target_x86_64::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
1070 if (gsym
->has_plt_offset())
1073 if (this->plt_
== NULL
)
1074 this->make_plt_section(symtab
, layout
);
1076 this->plt_
->add_entry(gsym
);
1079 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1082 Target_x86_64::make_local_ifunc_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
1083 Sized_relobj
<64, false>* relobj
,
1084 unsigned int local_sym_index
)
1086 if (relobj
->local_has_plt_offset(local_sym_index
))
1088 if (this->plt_
== NULL
)
1089 this->make_plt_section(symtab
, layout
);
1090 unsigned int plt_offset
= this->plt_
->add_local_ifunc_entry(relobj
,
1092 relobj
->set_local_plt_offset(local_sym_index
, plt_offset
);
1095 // Return the number of entries in the PLT.
1098 Target_x86_64::plt_entry_count() const
1100 if (this->plt_
== NULL
)
1102 return this->plt_
->entry_count();
1105 // Return the offset of the first non-reserved PLT entry.
1108 Target_x86_64::first_plt_entry_offset() const
1110 return Output_data_plt_x86_64::first_plt_entry_offset();
1113 // Return the size of each PLT entry.
1116 Target_x86_64::plt_entry_size() const
1118 return Output_data_plt_x86_64::get_plt_entry_size();
1121 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1124 Target_x86_64::define_tls_base_symbol(Symbol_table
* symtab
, Layout
* layout
)
1126 if (this->tls_base_symbol_defined_
)
1129 Output_segment
* tls_segment
= layout
->tls_segment();
1130 if (tls_segment
!= NULL
)
1132 bool is_exec
= parameters
->options().output_is_executable();
1133 symtab
->define_in_output_segment("_TLS_MODULE_BASE_", NULL
,
1134 Symbol_table::PREDEFINED
,
1138 elfcpp::STV_HIDDEN
, 0,
1140 ? Symbol::SEGMENT_END
1141 : Symbol::SEGMENT_START
),
1144 this->tls_base_symbol_defined_
= true;
1147 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1150 Target_x86_64::reserve_tlsdesc_entries(Symbol_table
* symtab
,
1153 if (this->plt_
== NULL
)
1154 this->make_plt_section(symtab
, layout
);
1156 if (!this->plt_
->has_tlsdesc_entry())
1158 // Allocate the TLSDESC_GOT entry.
1159 Output_data_got
<64, false>* got
= this->got_section(symtab
, layout
);
1160 unsigned int got_offset
= got
->add_constant(0);
1162 // Allocate the TLSDESC_PLT entry.
1163 this->plt_
->reserve_tlsdesc_entry(got_offset
);
1167 // Create a GOT entry for the TLS module index.
1170 Target_x86_64::got_mod_index_entry(Symbol_table
* symtab
, Layout
* layout
,
1171 Sized_relobj
<64, false>* object
)
1173 if (this->got_mod_index_offset_
== -1U)
1175 gold_assert(symtab
!= NULL
&& layout
!= NULL
&& object
!= NULL
);
1176 Reloc_section
* rela_dyn
= this->rela_dyn_section(layout
);
1177 Output_data_got
<64, false>* got
= this->got_section(symtab
, layout
);
1178 unsigned int got_offset
= got
->add_constant(0);
1179 rela_dyn
->add_local(object
, 0, elfcpp::R_X86_64_DTPMOD64
, got
,
1181 got
->add_constant(0);
1182 this->got_mod_index_offset_
= got_offset
;
1184 return this->got_mod_index_offset_
;
1187 // Optimize the TLS relocation type based on what we know about the
1188 // symbol. IS_FINAL is true if the final address of this symbol is
1189 // known at link time.
1191 tls::Tls_optimization
1192 Target_x86_64::optimize_tls_reloc(bool is_final
, int r_type
)
1194 // If we are generating a shared library, then we can't do anything
1196 if (parameters
->options().shared())
1197 return tls::TLSOPT_NONE
;
1201 case elfcpp::R_X86_64_TLSGD
:
1202 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
1203 case elfcpp::R_X86_64_TLSDESC_CALL
:
1204 // These are General-Dynamic which permits fully general TLS
1205 // access. Since we know that we are generating an executable,
1206 // we can convert this to Initial-Exec. If we also know that
1207 // this is a local symbol, we can further switch to Local-Exec.
1209 return tls::TLSOPT_TO_LE
;
1210 return tls::TLSOPT_TO_IE
;
1212 case elfcpp::R_X86_64_TLSLD
:
1213 // This is Local-Dynamic, which refers to a local symbol in the
1214 // dynamic TLS block. Since we know that we generating an
1215 // executable, we can switch to Local-Exec.
1216 return tls::TLSOPT_TO_LE
;
1218 case elfcpp::R_X86_64_DTPOFF32
:
1219 case elfcpp::R_X86_64_DTPOFF64
:
1220 // Another Local-Dynamic reloc.
1221 return tls::TLSOPT_TO_LE
;
1223 case elfcpp::R_X86_64_GOTTPOFF
:
1224 // These are Initial-Exec relocs which get the thread offset
1225 // from the GOT. If we know that we are linking against the
1226 // local symbol, we can switch to Local-Exec, which links the
1227 // thread offset into the instruction.
1229 return tls::TLSOPT_TO_LE
;
1230 return tls::TLSOPT_NONE
;
1232 case elfcpp::R_X86_64_TPOFF32
:
1233 // When we already have Local-Exec, there is nothing further we
1235 return tls::TLSOPT_NONE
;
1242 // Get the Reference_flags for a particular relocation.
1245 Target_x86_64::Scan::get_reference_flags(unsigned int r_type
)
1249 case elfcpp::R_X86_64_NONE
:
1250 case elfcpp::R_X86_64_GNU_VTINHERIT
:
1251 case elfcpp::R_X86_64_GNU_VTENTRY
:
1252 case elfcpp::R_X86_64_GOTPC32
:
1253 case elfcpp::R_X86_64_GOTPC64
:
1254 // No symbol reference.
1257 case elfcpp::R_X86_64_64
:
1258 case elfcpp::R_X86_64_32
:
1259 case elfcpp::R_X86_64_32S
:
1260 case elfcpp::R_X86_64_16
:
1261 case elfcpp::R_X86_64_8
:
1262 return Symbol::ABSOLUTE_REF
;
1264 case elfcpp::R_X86_64_PC64
:
1265 case elfcpp::R_X86_64_PC32
:
1266 case elfcpp::R_X86_64_PC16
:
1267 case elfcpp::R_X86_64_PC8
:
1268 case elfcpp::R_X86_64_GOTOFF64
:
1269 return Symbol::RELATIVE_REF
;
1271 case elfcpp::R_X86_64_PLT32
:
1272 case elfcpp::R_X86_64_PLTOFF64
:
1273 return Symbol::FUNCTION_CALL
| Symbol::RELATIVE_REF
;
1275 case elfcpp::R_X86_64_GOT64
:
1276 case elfcpp::R_X86_64_GOT32
:
1277 case elfcpp::R_X86_64_GOTPCREL64
:
1278 case elfcpp::R_X86_64_GOTPCREL
:
1279 case elfcpp::R_X86_64_GOTPLT64
:
1281 return Symbol::ABSOLUTE_REF
;
1283 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1284 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1285 case elfcpp::R_X86_64_TLSDESC_CALL
:
1286 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1287 case elfcpp::R_X86_64_DTPOFF32
:
1288 case elfcpp::R_X86_64_DTPOFF64
:
1289 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1290 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1291 return Symbol::TLS_REF
;
1293 case elfcpp::R_X86_64_COPY
:
1294 case elfcpp::R_X86_64_GLOB_DAT
:
1295 case elfcpp::R_X86_64_JUMP_SLOT
:
1296 case elfcpp::R_X86_64_RELATIVE
:
1297 case elfcpp::R_X86_64_IRELATIVE
:
1298 case elfcpp::R_X86_64_TPOFF64
:
1299 case elfcpp::R_X86_64_DTPMOD64
:
1300 case elfcpp::R_X86_64_TLSDESC
:
1301 case elfcpp::R_X86_64_SIZE32
:
1302 case elfcpp::R_X86_64_SIZE64
:
1304 // Not expected. We will give an error later.
1309 // Report an unsupported relocation against a local symbol.
1312 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj
<64, false>* object
,
1313 unsigned int r_type
)
1315 gold_error(_("%s: unsupported reloc %u against local symbol"),
1316 object
->name().c_str(), r_type
);
1319 // We are about to emit a dynamic relocation of type R_TYPE. If the
1320 // dynamic linker does not support it, issue an error. The GNU linker
1321 // only issues a non-PIC error for an allocated read-only section.
1322 // Here we know the section is allocated, but we don't know that it is
1323 // read-only. But we check for all the relocation types which the
1324 // glibc dynamic linker supports, so it seems appropriate to issue an
1325 // error even if the section is not read-only.
1328 Target_x86_64::Scan::check_non_pic(Relobj
* object
, unsigned int r_type
)
1332 // These are the relocation types supported by glibc for x86_64
1333 // which should always work.
1334 case elfcpp::R_X86_64_RELATIVE
:
1335 case elfcpp::R_X86_64_IRELATIVE
:
1336 case elfcpp::R_X86_64_GLOB_DAT
:
1337 case elfcpp::R_X86_64_JUMP_SLOT
:
1338 case elfcpp::R_X86_64_DTPMOD64
:
1339 case elfcpp::R_X86_64_DTPOFF64
:
1340 case elfcpp::R_X86_64_TPOFF64
:
1341 case elfcpp::R_X86_64_64
:
1342 case elfcpp::R_X86_64_COPY
:
1345 // glibc supports these reloc types, but they can overflow.
1346 case elfcpp::R_X86_64_32
:
1347 case elfcpp::R_X86_64_PC32
:
1348 if (this->issued_non_pic_error_
)
1350 gold_assert(parameters
->options().output_is_position_independent());
1351 object
->error(_("requires dynamic reloc which may overflow at runtime; "
1352 "recompile with -fPIC"));
1353 this->issued_non_pic_error_
= true;
1357 // This prevents us from issuing more than one error per reloc
1358 // section. But we can still wind up issuing more than one
1359 // error per object file.
1360 if (this->issued_non_pic_error_
)
1362 gold_assert(parameters
->options().output_is_position_independent());
1363 object
->error(_("requires unsupported dynamic reloc; "
1364 "recompile with -fPIC"));
1365 this->issued_non_pic_error_
= true;
1368 case elfcpp::R_X86_64_NONE
:
1373 // Return whether we need to make a PLT entry for a relocation of the
1374 // given type against a STT_GNU_IFUNC symbol.
1377 Target_x86_64::Scan::reloc_needs_plt_for_ifunc(Sized_relobj
<64, false>* object
,
1378 unsigned int r_type
)
1380 int flags
= Scan::get_reference_flags(r_type
);
1381 if (flags
& Symbol::TLS_REF
)
1382 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1383 object
->name().c_str(), r_type
);
1387 // Scan a relocation for a local symbol.
1390 Target_x86_64::Scan::local(Symbol_table
* symtab
,
1392 Target_x86_64
* target
,
1393 Sized_relobj
<64, false>* object
,
1394 unsigned int data_shndx
,
1395 Output_section
* output_section
,
1396 const elfcpp::Rela
<64, false>& reloc
,
1397 unsigned int r_type
,
1398 const elfcpp::Sym
<64, false>& lsym
)
1400 // A local STT_GNU_IFUNC symbol may require a PLT entry.
1401 if (lsym
.get_st_type() == elfcpp::STT_GNU_IFUNC
1402 && this->reloc_needs_plt_for_ifunc(object
, r_type
))
1404 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1405 target
->make_local_ifunc_plt_entry(symtab
, layout
, object
, r_sym
);
1410 case elfcpp::R_X86_64_NONE
:
1411 case elfcpp::R_X86_64_GNU_VTINHERIT
:
1412 case elfcpp::R_X86_64_GNU_VTENTRY
:
1415 case elfcpp::R_X86_64_64
:
1416 // If building a shared library (or a position-independent
1417 // executable), we need to create a dynamic relocation for this
1418 // location. The relocation applied at link time will apply the
1419 // link-time value, so we flag the location with an
1420 // R_X86_64_RELATIVE relocation so the dynamic loader can
1421 // relocate it easily.
1422 if (parameters
->options().output_is_position_independent())
1424 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1425 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1426 rela_dyn
->add_local_relative(object
, r_sym
,
1427 elfcpp::R_X86_64_RELATIVE
,
1428 output_section
, data_shndx
,
1429 reloc
.get_r_offset(),
1430 reloc
.get_r_addend());
1434 case elfcpp::R_X86_64_32
:
1435 case elfcpp::R_X86_64_32S
:
1436 case elfcpp::R_X86_64_16
:
1437 case elfcpp::R_X86_64_8
:
1438 // If building a shared library (or a position-independent
1439 // executable), we need to create a dynamic relocation for this
1440 // location. We can't use an R_X86_64_RELATIVE relocation
1441 // because that is always a 64-bit relocation.
1442 if (parameters
->options().output_is_position_independent())
1444 this->check_non_pic(object
, r_type
);
1446 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1447 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1448 if (lsym
.get_st_type() != elfcpp::STT_SECTION
)
1449 rela_dyn
->add_local(object
, r_sym
, r_type
, output_section
,
1450 data_shndx
, reloc
.get_r_offset(),
1451 reloc
.get_r_addend());
1454 gold_assert(lsym
.get_st_value() == 0);
1455 unsigned int shndx
= lsym
.get_st_shndx();
1457 shndx
= object
->adjust_sym_shndx(r_sym
, shndx
,
1460 object
->error(_("section symbol %u has bad shndx %u"),
1463 rela_dyn
->add_local_section(object
, shndx
,
1464 r_type
, output_section
,
1465 data_shndx
, reloc
.get_r_offset(),
1466 reloc
.get_r_addend());
1471 case elfcpp::R_X86_64_PC64
:
1472 case elfcpp::R_X86_64_PC32
:
1473 case elfcpp::R_X86_64_PC16
:
1474 case elfcpp::R_X86_64_PC8
:
1477 case elfcpp::R_X86_64_PLT32
:
1478 // Since we know this is a local symbol, we can handle this as a
1482 case elfcpp::R_X86_64_GOTPC32
:
1483 case elfcpp::R_X86_64_GOTOFF64
:
1484 case elfcpp::R_X86_64_GOTPC64
:
1485 case elfcpp::R_X86_64_PLTOFF64
:
1486 // We need a GOT section.
1487 target
->got_section(symtab
, layout
);
1488 // For PLTOFF64, we'd normally want a PLT section, but since we
1489 // know this is a local symbol, no PLT is needed.
1492 case elfcpp::R_X86_64_GOT64
:
1493 case elfcpp::R_X86_64_GOT32
:
1494 case elfcpp::R_X86_64_GOTPCREL64
:
1495 case elfcpp::R_X86_64_GOTPCREL
:
1496 case elfcpp::R_X86_64_GOTPLT64
:
1498 // The symbol requires a GOT entry.
1499 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
1500 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1502 // For a STT_GNU_IFUNC symbol we want the PLT offset. That
1503 // lets function pointers compare correctly with shared
1504 // libraries. Otherwise we would need an IRELATIVE reloc.
1506 if (lsym
.get_st_type() == elfcpp::STT_GNU_IFUNC
)
1507 is_new
= got
->add_local_plt(object
, r_sym
, GOT_TYPE_STANDARD
);
1509 is_new
= got
->add_local(object
, r_sym
, GOT_TYPE_STANDARD
);
1512 // If we are generating a shared object, we need to add a
1513 // dynamic relocation for this symbol's GOT entry.
1514 if (parameters
->options().output_is_position_independent())
1516 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1517 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1518 if (r_type
!= elfcpp::R_X86_64_GOT32
)
1520 unsigned int got_offset
=
1521 object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
);
1522 rela_dyn
->add_local_relative(object
, r_sym
,
1523 elfcpp::R_X86_64_RELATIVE
,
1524 got
, got_offset
, 0);
1528 this->check_non_pic(object
, r_type
);
1530 gold_assert(lsym
.get_st_type() != elfcpp::STT_SECTION
);
1531 rela_dyn
->add_local(
1532 object
, r_sym
, r_type
, got
,
1533 object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
), 0);
1537 // For GOTPLT64, we'd normally want a PLT section, but since
1538 // we know this is a local symbol, no PLT is needed.
1542 case elfcpp::R_X86_64_COPY
:
1543 case elfcpp::R_X86_64_GLOB_DAT
:
1544 case elfcpp::R_X86_64_JUMP_SLOT
:
1545 case elfcpp::R_X86_64_RELATIVE
:
1546 case elfcpp::R_X86_64_IRELATIVE
:
1547 // These are outstanding tls relocs, which are unexpected when linking
1548 case elfcpp::R_X86_64_TPOFF64
:
1549 case elfcpp::R_X86_64_DTPMOD64
:
1550 case elfcpp::R_X86_64_TLSDESC
:
1551 gold_error(_("%s: unexpected reloc %u in object file"),
1552 object
->name().c_str(), r_type
);
1555 // These are initial tls relocs, which are expected when linking
1556 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1557 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1558 case elfcpp::R_X86_64_TLSDESC_CALL
:
1559 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1560 case elfcpp::R_X86_64_DTPOFF32
:
1561 case elfcpp::R_X86_64_DTPOFF64
:
1562 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1563 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1565 bool output_is_shared
= parameters
->options().shared();
1566 const tls::Tls_optimization optimized_type
1567 = Target_x86_64::optimize_tls_reloc(!output_is_shared
, r_type
);
1570 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
1571 if (optimized_type
== tls::TLSOPT_NONE
)
1573 // Create a pair of GOT entries for the module index and
1574 // dtv-relative offset.
1575 Output_data_got
<64, false>* got
1576 = target
->got_section(symtab
, layout
);
1577 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1578 unsigned int shndx
= lsym
.get_st_shndx();
1580 shndx
= object
->adjust_sym_shndx(r_sym
, shndx
, &is_ordinary
);
1582 object
->error(_("local symbol %u has bad shndx %u"),
1585 got
->add_local_pair_with_rela(object
, r_sym
,
1588 target
->rela_dyn_section(layout
),
1589 elfcpp::R_X86_64_DTPMOD64
, 0);
1591 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1592 unsupported_reloc_local(object
, r_type
);
1595 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
1596 target
->define_tls_base_symbol(symtab
, layout
);
1597 if (optimized_type
== tls::TLSOPT_NONE
)
1599 // Create reserved PLT and GOT entries for the resolver.
1600 target
->reserve_tlsdesc_entries(symtab
, layout
);
1602 // Generate a double GOT entry with an
1603 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc
1604 // is resolved lazily, so the GOT entry needs to be in
1605 // an area in .got.plt, not .got. Call got_section to
1606 // make sure the section has been created.
1607 target
->got_section(symtab
, layout
);
1608 Output_data_got
<64, false>* got
= target
->got_tlsdesc_section();
1609 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1610 if (!object
->local_has_got_offset(r_sym
, GOT_TYPE_TLS_DESC
))
1612 unsigned int got_offset
= got
->add_constant(0);
1613 got
->add_constant(0);
1614 object
->set_local_got_offset(r_sym
, GOT_TYPE_TLS_DESC
,
1616 Reloc_section
* rt
= target
->rela_tlsdesc_section(layout
);
1617 // We store the arguments we need in a vector, and
1618 // use the index into the vector as the parameter
1619 // to pass to the target specific routines.
1620 uintptr_t intarg
= target
->add_tlsdesc_info(object
, r_sym
);
1621 void* arg
= reinterpret_cast<void*>(intarg
);
1622 rt
->add_target_specific(elfcpp::R_X86_64_TLSDESC
, arg
,
1623 got
, got_offset
, 0);
1626 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1627 unsupported_reloc_local(object
, r_type
);
1630 case elfcpp::R_X86_64_TLSDESC_CALL
:
1633 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1634 if (optimized_type
== tls::TLSOPT_NONE
)
1636 // Create a GOT entry for the module index.
1637 target
->got_mod_index_entry(symtab
, layout
, object
);
1639 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1640 unsupported_reloc_local(object
, r_type
);
1643 case elfcpp::R_X86_64_DTPOFF32
:
1644 case elfcpp::R_X86_64_DTPOFF64
:
1647 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1648 layout
->set_has_static_tls();
1649 if (optimized_type
== tls::TLSOPT_NONE
)
1651 // Create a GOT entry for the tp-relative offset.
1652 Output_data_got
<64, false>* got
1653 = target
->got_section(symtab
, layout
);
1654 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(reloc
.get_r_info());
1655 got
->add_local_with_rela(object
, r_sym
, GOT_TYPE_TLS_OFFSET
,
1656 target
->rela_dyn_section(layout
),
1657 elfcpp::R_X86_64_TPOFF64
);
1659 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
1660 unsupported_reloc_local(object
, r_type
);
1663 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1664 layout
->set_has_static_tls();
1665 if (output_is_shared
)
1666 unsupported_reloc_local(object
, r_type
);
1675 case elfcpp::R_X86_64_SIZE32
:
1676 case elfcpp::R_X86_64_SIZE64
:
1678 gold_error(_("%s: unsupported reloc %u against local symbol"),
1679 object
->name().c_str(), r_type
);
1685 // Report an unsupported relocation against a global symbol.
1688 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj
<64, false>* object
,
1689 unsigned int r_type
,
1692 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1693 object
->name().c_str(), r_type
, gsym
->demangled_name().c_str());
1696 // Returns true if this relocation type could be that of a function pointer.
1698 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type
)
1702 case elfcpp::R_X86_64_64
:
1703 case elfcpp::R_X86_64_32
:
1704 case elfcpp::R_X86_64_32S
:
1705 case elfcpp::R_X86_64_16
:
1706 case elfcpp::R_X86_64_8
:
1707 case elfcpp::R_X86_64_GOT64
:
1708 case elfcpp::R_X86_64_GOT32
:
1709 case elfcpp::R_X86_64_GOTPCREL64
:
1710 case elfcpp::R_X86_64_GOTPCREL
:
1711 case elfcpp::R_X86_64_GOTPLT64
:
1719 // For safe ICF, scan a relocation for a local symbol to check if it
1720 // corresponds to a function pointer being taken. In that case mark
1721 // the function whose pointer was taken as not foldable.
1724 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1728 Sized_relobj
<64, false>* ,
1731 const elfcpp::Rela
<64, false>& ,
1732 unsigned int r_type
,
1733 const elfcpp::Sym
<64, false>&)
1735 // When building a shared library, do not fold any local symbols as it is
1736 // not possible to distinguish pointer taken versus a call by looking at
1737 // the relocation types.
1738 return (parameters
->options().shared()
1739 || possible_function_pointer_reloc(r_type
));
1742 // For safe ICF, scan a relocation for a global symbol to check if it
1743 // corresponds to a function pointer being taken. In that case mark
1744 // the function whose pointer was taken as not foldable.
1747 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1751 Sized_relobj
<64, false>* ,
1754 const elfcpp::Rela
<64, false>& ,
1755 unsigned int r_type
,
1758 // When building a shared library, do not fold symbols whose visibility
1759 // is hidden, internal or protected.
1760 return ((parameters
->options().shared()
1761 && (gsym
->visibility() == elfcpp::STV_INTERNAL
1762 || gsym
->visibility() == elfcpp::STV_PROTECTED
1763 || gsym
->visibility() == elfcpp::STV_HIDDEN
))
1764 || possible_function_pointer_reloc(r_type
));
1767 // Scan a relocation for a global symbol.
1770 Target_x86_64::Scan::global(Symbol_table
* symtab
,
1772 Target_x86_64
* target
,
1773 Sized_relobj
<64, false>* object
,
1774 unsigned int data_shndx
,
1775 Output_section
* output_section
,
1776 const elfcpp::Rela
<64, false>& reloc
,
1777 unsigned int r_type
,
1780 // A STT_GNU_IFUNC symbol may require a PLT entry.
1781 if (gsym
->type() == elfcpp::STT_GNU_IFUNC
1782 && this->reloc_needs_plt_for_ifunc(object
, r_type
))
1783 target
->make_plt_entry(symtab
, layout
, gsym
);
1787 case elfcpp::R_X86_64_NONE
:
1788 case elfcpp::R_X86_64_GNU_VTINHERIT
:
1789 case elfcpp::R_X86_64_GNU_VTENTRY
:
1792 case elfcpp::R_X86_64_64
:
1793 case elfcpp::R_X86_64_32
:
1794 case elfcpp::R_X86_64_32S
:
1795 case elfcpp::R_X86_64_16
:
1796 case elfcpp::R_X86_64_8
:
1798 // Make a PLT entry if necessary.
1799 if (gsym
->needs_plt_entry())
1801 target
->make_plt_entry(symtab
, layout
, gsym
);
1802 // Since this is not a PC-relative relocation, we may be
1803 // taking the address of a function. In that case we need to
1804 // set the entry in the dynamic symbol table to the address of
1806 if (gsym
->is_from_dynobj() && !parameters
->options().shared())
1807 gsym
->set_needs_dynsym_value();
1809 // Make a dynamic relocation if necessary.
1810 if (gsym
->needs_dynamic_reloc(Scan::get_reference_flags(r_type
)))
1812 if (gsym
->may_need_copy_reloc())
1814 target
->copy_reloc(symtab
, layout
, object
,
1815 data_shndx
, output_section
, gsym
, reloc
);
1817 else if (r_type
== elfcpp::R_X86_64_64
1818 && gsym
->type() == elfcpp::STT_GNU_IFUNC
1819 && gsym
->can_use_relative_reloc(false)
1820 && !gsym
->is_from_dynobj()
1821 && !gsym
->is_undefined()
1822 && !gsym
->is_preemptible())
1824 // Use an IRELATIVE reloc for a locally defined
1825 // STT_GNU_IFUNC symbol. This makes a function
1826 // address in a PIE executable match the address in a
1827 // shared library that it links against.
1828 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1829 unsigned int r_type
= elfcpp::R_X86_64_IRELATIVE
;
1830 rela_dyn
->add_symbolless_global_addend(gsym
, r_type
,
1831 output_section
, object
,
1833 reloc
.get_r_offset(),
1834 reloc
.get_r_addend());
1836 else if (r_type
== elfcpp::R_X86_64_64
1837 && gsym
->can_use_relative_reloc(false))
1839 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1840 rela_dyn
->add_global_relative(gsym
, elfcpp::R_X86_64_RELATIVE
,
1841 output_section
, object
,
1843 reloc
.get_r_offset(),
1844 reloc
.get_r_addend());
1848 this->check_non_pic(object
, r_type
);
1849 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1850 rela_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1851 data_shndx
, reloc
.get_r_offset(),
1852 reloc
.get_r_addend());
1858 case elfcpp::R_X86_64_PC64
:
1859 case elfcpp::R_X86_64_PC32
:
1860 case elfcpp::R_X86_64_PC16
:
1861 case elfcpp::R_X86_64_PC8
:
1863 // Make a PLT entry if necessary.
1864 if (gsym
->needs_plt_entry())
1865 target
->make_plt_entry(symtab
, layout
, gsym
);
1866 // Make a dynamic relocation if necessary.
1867 if (gsym
->needs_dynamic_reloc(Scan::get_reference_flags(r_type
)))
1869 if (gsym
->may_need_copy_reloc())
1871 target
->copy_reloc(symtab
, layout
, object
,
1872 data_shndx
, output_section
, gsym
, reloc
);
1876 this->check_non_pic(object
, r_type
);
1877 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1878 rela_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1879 data_shndx
, reloc
.get_r_offset(),
1880 reloc
.get_r_addend());
1886 case elfcpp::R_X86_64_GOT64
:
1887 case elfcpp::R_X86_64_GOT32
:
1888 case elfcpp::R_X86_64_GOTPCREL64
:
1889 case elfcpp::R_X86_64_GOTPCREL
:
1890 case elfcpp::R_X86_64_GOTPLT64
:
1892 // The symbol requires a GOT entry.
1893 Output_data_got
<64, false>* got
= target
->got_section(symtab
, layout
);
1894 if (gsym
->final_value_is_known())
1896 // For a STT_GNU_IFUNC symbol we want the PLT address.
1897 if (gsym
->type() == elfcpp::STT_GNU_IFUNC
)
1898 got
->add_global_plt(gsym
, GOT_TYPE_STANDARD
);
1900 got
->add_global(gsym
, GOT_TYPE_STANDARD
);
1904 // If this symbol is not fully resolved, we need to add a
1905 // dynamic relocation for it.
1906 Reloc_section
* rela_dyn
= target
->rela_dyn_section(layout
);
1907 if (gsym
->is_from_dynobj()
1908 || gsym
->is_undefined()
1909 || gsym
->is_preemptible()
1910 || (gsym
->type() == elfcpp::STT_GNU_IFUNC
1911 && parameters
->options().output_is_position_independent()))
1912 got
->add_global_with_rela(gsym
, GOT_TYPE_STANDARD
, rela_dyn
,
1913 elfcpp::R_X86_64_GLOB_DAT
);
1916 // For a STT_GNU_IFUNC symbol we want to write the PLT
1917 // offset into the GOT, so that function pointer
1918 // comparisons work correctly.
1920 if (gsym
->type() != elfcpp::STT_GNU_IFUNC
)
1921 is_new
= got
->add_global(gsym
, GOT_TYPE_STANDARD
);
1924 is_new
= got
->add_global_plt(gsym
, GOT_TYPE_STANDARD
);
1925 // Tell the dynamic linker to use the PLT address
1926 // when resolving relocations.
1927 if (gsym
->is_from_dynobj()
1928 && !parameters
->options().shared())
1929 gsym
->set_needs_dynsym_value();
1933 unsigned int got_off
= gsym
->got_offset(GOT_TYPE_STANDARD
);
1934 rela_dyn
->add_global_relative(gsym
,
1935 elfcpp::R_X86_64_RELATIVE
,
1940 // For GOTPLT64, we also need a PLT entry (but only if the
1941 // symbol is not fully resolved).
1942 if (r_type
== elfcpp::R_X86_64_GOTPLT64
1943 && !gsym
->final_value_is_known())
1944 target
->make_plt_entry(symtab
, layout
, gsym
);
1948 case elfcpp::R_X86_64_PLT32
:
1949 // If the symbol is fully resolved, this is just a PC32 reloc.
1950 // Otherwise we need a PLT entry.
1951 if (gsym
->final_value_is_known())
1953 // If building a shared library, we can also skip the PLT entry
1954 // if the symbol is defined in the output file and is protected
1956 if (gsym
->is_defined()
1957 && !gsym
->is_from_dynobj()
1958 && !gsym
->is_preemptible())
1960 target
->make_plt_entry(symtab
, layout
, gsym
);
1963 case elfcpp::R_X86_64_GOTPC32
:
1964 case elfcpp::R_X86_64_GOTOFF64
:
1965 case elfcpp::R_X86_64_GOTPC64
:
1966 case elfcpp::R_X86_64_PLTOFF64
:
1967 // We need a GOT section.
1968 target
->got_section(symtab
, layout
);
1969 // For PLTOFF64, we also need a PLT entry (but only if the
1970 // symbol is not fully resolved).
1971 if (r_type
== elfcpp::R_X86_64_PLTOFF64
1972 && !gsym
->final_value_is_known())
1973 target
->make_plt_entry(symtab
, layout
, gsym
);
1976 case elfcpp::R_X86_64_COPY
:
1977 case elfcpp::R_X86_64_GLOB_DAT
:
1978 case elfcpp::R_X86_64_JUMP_SLOT
:
1979 case elfcpp::R_X86_64_RELATIVE
:
1980 case elfcpp::R_X86_64_IRELATIVE
:
1981 // These are outstanding tls relocs, which are unexpected when linking
1982 case elfcpp::R_X86_64_TPOFF64
:
1983 case elfcpp::R_X86_64_DTPMOD64
:
1984 case elfcpp::R_X86_64_TLSDESC
:
1985 gold_error(_("%s: unexpected reloc %u in object file"),
1986 object
->name().c_str(), r_type
);
1989 // These are initial tls relocs, which are expected for global()
1990 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
1991 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
1992 case elfcpp::R_X86_64_TLSDESC_CALL
:
1993 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
1994 case elfcpp::R_X86_64_DTPOFF32
:
1995 case elfcpp::R_X86_64_DTPOFF64
:
1996 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
1997 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
1999 const bool is_final
= gsym
->final_value_is_known();
2000 const tls::Tls_optimization optimized_type
2001 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
2004 case elfcpp::R_X86_64_TLSGD
: // General-dynamic
2005 if (optimized_type
== tls::TLSOPT_NONE
)
2007 // Create a pair of GOT entries for the module index and
2008 // dtv-relative offset.
2009 Output_data_got
<64, false>* got
2010 = target
->got_section(symtab
, layout
);
2011 got
->add_global_pair_with_rela(gsym
, GOT_TYPE_TLS_PAIR
,
2012 target
->rela_dyn_section(layout
),
2013 elfcpp::R_X86_64_DTPMOD64
,
2014 elfcpp::R_X86_64_DTPOFF64
);
2016 else if (optimized_type
== tls::TLSOPT_TO_IE
)
2018 // Create a GOT entry for the tp-relative offset.
2019 Output_data_got
<64, false>* got
2020 = target
->got_section(symtab
, layout
);
2021 got
->add_global_with_rela(gsym
, GOT_TYPE_TLS_OFFSET
,
2022 target
->rela_dyn_section(layout
),
2023 elfcpp::R_X86_64_TPOFF64
);
2025 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
2026 unsupported_reloc_global(object
, r_type
, gsym
);
2029 case elfcpp::R_X86_64_GOTPC32_TLSDESC
:
2030 target
->define_tls_base_symbol(symtab
, layout
);
2031 if (optimized_type
== tls::TLSOPT_NONE
)
2033 // Create reserved PLT and GOT entries for the resolver.
2034 target
->reserve_tlsdesc_entries(symtab
, layout
);
2036 // Create a double GOT entry with an R_X86_64_TLSDESC
2037 // reloc. The R_X86_64_TLSDESC reloc is resolved
2038 // lazily, so the GOT entry needs to be in an area in
2039 // .got.plt, not .got. Call got_section to make sure
2040 // the section has been created.
2041 target
->got_section(symtab
, layout
);
2042 Output_data_got
<64, false>* got
= target
->got_tlsdesc_section();
2043 Reloc_section
* rt
= target
->rela_tlsdesc_section(layout
);
2044 got
->add_global_pair_with_rela(gsym
, GOT_TYPE_TLS_DESC
, rt
,
2045 elfcpp::R_X86_64_TLSDESC
, 0);
2047 else if (optimized_type
== tls::TLSOPT_TO_IE
)
2049 // Create a GOT entry for the tp-relative offset.
2050 Output_data_got
<64, false>* got
2051 = target
->got_section(symtab
, layout
);
2052 got
->add_global_with_rela(gsym
, GOT_TYPE_TLS_OFFSET
,
2053 target
->rela_dyn_section(layout
),
2054 elfcpp::R_X86_64_TPOFF64
);
2056 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
2057 unsupported_reloc_global(object
, r_type
, gsym
);
2060 case elfcpp::R_X86_64_TLSDESC_CALL
:
2063 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
2064 if (optimized_type
== tls::TLSOPT_NONE
)
2066 // Create a GOT entry for the module index.
2067 target
->got_mod_index_entry(symtab
, layout
, object
);
2069 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
2070 unsupported_reloc_global(object
, r_type
, gsym
);
2073 case elfcpp::R_X86_64_DTPOFF32
:
2074 case elfcpp::R_X86_64_DTPOFF64
:
2077 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
2078 layout
->set_has_static_tls();
2079 if (optimized_type
== tls::TLSOPT_NONE
)
2081 // Create a GOT entry for the tp-relative offset.
2082 Output_data_got
<64, false>* got
2083 = target
->got_section(symtab
, layout
);
2084 got
->add_global_with_rela(gsym
, GOT_TYPE_TLS_OFFSET
,
2085 target
->rela_dyn_section(layout
),
2086 elfcpp::R_X86_64_TPOFF64
);
2088 else if (optimized_type
!= tls::TLSOPT_TO_LE
)
2089 unsupported_reloc_global(object
, r_type
, gsym
);
2092 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
2093 layout
->set_has_static_tls();
2094 if (parameters
->options().shared())
2095 unsupported_reloc_local(object
, r_type
);
2104 case elfcpp::R_X86_64_SIZE32
:
2105 case elfcpp::R_X86_64_SIZE64
:
2107 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2108 object
->name().c_str(), r_type
,
2109 gsym
->demangled_name().c_str());
2115 Target_x86_64::gc_process_relocs(Symbol_table
* symtab
,
2117 Sized_relobj
<64, false>* object
,
2118 unsigned int data_shndx
,
2119 unsigned int sh_type
,
2120 const unsigned char* prelocs
,
2122 Output_section
* output_section
,
2123 bool needs_special_offset_handling
,
2124 size_t local_symbol_count
,
2125 const unsigned char* plocal_symbols
)
2128 if (sh_type
== elfcpp::SHT_REL
)
2133 gold::gc_process_relocs
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
2134 Target_x86_64::Scan
,
2135 Target_x86_64::Relocatable_size_for_reloc
>(
2144 needs_special_offset_handling
,
2149 // Scan relocations for a section.
2152 Target_x86_64::scan_relocs(Symbol_table
* symtab
,
2154 Sized_relobj
<64, false>* object
,
2155 unsigned int data_shndx
,
2156 unsigned int sh_type
,
2157 const unsigned char* prelocs
,
2159 Output_section
* output_section
,
2160 bool needs_special_offset_handling
,
2161 size_t local_symbol_count
,
2162 const unsigned char* plocal_symbols
)
2164 if (sh_type
== elfcpp::SHT_REL
)
2166 gold_error(_("%s: unsupported REL reloc section"),
2167 object
->name().c_str());
2171 gold::scan_relocs
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
2172 Target_x86_64::Scan
>(
2181 needs_special_offset_handling
,
2186 // Finalize the sections.
2189 Target_x86_64::do_finalize_sections(
2191 const Input_objects
*,
2192 Symbol_table
* symtab
)
2194 const Reloc_section
* rel_plt
= (this->plt_
== NULL
2196 : this->plt_
->rela_plt());
2197 layout
->add_target_dynamic_tags(false, this->got_plt_
, rel_plt
,
2198 this->rela_dyn_
, true, false);
2200 // Fill in some more dynamic tags.
2201 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
2204 if (this->plt_
!= NULL
2205 && this->plt_
->output_section() != NULL
2206 && this->plt_
->has_tlsdesc_entry())
2208 unsigned int plt_offset
= this->plt_
->get_tlsdesc_plt_offset();
2209 unsigned int got_offset
= this->plt_
->get_tlsdesc_got_offset();
2210 this->got_
->finalize_data_size();
2211 odyn
->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT
,
2212 this->plt_
, plt_offset
);
2213 odyn
->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT
,
2214 this->got_
, got_offset
);
2218 // Emit any relocs we saved in an attempt to avoid generating COPY
2220 if (this->copy_relocs_
.any_saved_relocs())
2221 this->copy_relocs_
.emit(this->rela_dyn_section(layout
));
2223 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2224 // the .got.plt section.
2225 Symbol
* sym
= this->global_offset_table_
;
2228 uint64_t data_size
= this->got_plt_
->current_data_size();
2229 symtab
->get_sized_symbol
<64>(sym
)->set_symsize(data_size
);
2233 // Perform a relocation.
2236 Target_x86_64::Relocate::relocate(const Relocate_info
<64, false>* relinfo
,
2237 Target_x86_64
* target
,
2240 const elfcpp::Rela
<64, false>& rela
,
2241 unsigned int r_type
,
2242 const Sized_symbol
<64>* gsym
,
2243 const Symbol_value
<64>* psymval
,
2244 unsigned char* view
,
2245 elfcpp::Elf_types
<64>::Elf_Addr address
,
2246 section_size_type view_size
)
2248 if (this->skip_call_tls_get_addr_
)
2250 if ((r_type
!= elfcpp::R_X86_64_PLT32
2251 && r_type
!= elfcpp::R_X86_64_PC32
)
2253 || strcmp(gsym
->name(), "__tls_get_addr") != 0)
2255 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2256 _("missing expected TLS relocation"));
2260 this->skip_call_tls_get_addr_
= false;
2265 const Sized_relobj
<64, false>* object
= relinfo
->object
;
2267 // Pick the value to use for symbols defined in the PLT.
2268 Symbol_value
<64> symval
;
2270 && gsym
->use_plt_offset(Scan::get_reference_flags(r_type
)))
2272 symval
.set_output_value(target
->plt_section()->address()
2273 + gsym
->plt_offset());
2276 else if (gsym
== NULL
&& psymval
->is_ifunc_symbol())
2278 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
2279 if (object
->local_has_plt_offset(r_sym
))
2281 symval
.set_output_value(target
->plt_section()->address()
2282 + object
->local_plt_offset(r_sym
));
2287 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
2289 // Get the GOT offset if needed.
2290 // The GOT pointer points to the end of the GOT section.
2291 // We need to subtract the size of the GOT section to get
2292 // the actual offset to use in the relocation.
2293 bool have_got_offset
= false;
2294 unsigned int got_offset
= 0;
2297 case elfcpp::R_X86_64_GOT32
:
2298 case elfcpp::R_X86_64_GOT64
:
2299 case elfcpp::R_X86_64_GOTPLT64
:
2300 case elfcpp::R_X86_64_GOTPCREL
:
2301 case elfcpp::R_X86_64_GOTPCREL64
:
2304 gold_assert(gsym
->has_got_offset(GOT_TYPE_STANDARD
));
2305 got_offset
= gsym
->got_offset(GOT_TYPE_STANDARD
) - target
->got_size();
2309 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
2310 gold_assert(object
->local_has_got_offset(r_sym
, GOT_TYPE_STANDARD
));
2311 got_offset
= (object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
)
2312 - target
->got_size());
2314 have_got_offset
= true;
2323 case elfcpp::R_X86_64_NONE
:
2324 case elfcpp::R_X86_64_GNU_VTINHERIT
:
2325 case elfcpp::R_X86_64_GNU_VTENTRY
:
2328 case elfcpp::R_X86_64_64
:
2329 Relocate_functions
<64, false>::rela64(view
, object
, psymval
, addend
);
2332 case elfcpp::R_X86_64_PC64
:
2333 Relocate_functions
<64, false>::pcrela64(view
, object
, psymval
, addend
,
2337 case elfcpp::R_X86_64_32
:
2338 // FIXME: we need to verify that value + addend fits into 32 bits:
2339 // uint64_t x = value + addend;
2340 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2341 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2342 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
2345 case elfcpp::R_X86_64_32S
:
2346 // FIXME: we need to verify that value + addend fits into 32 bits:
2347 // int64_t x = value + addend; // note this quantity is signed!
2348 // x == static_cast<int64_t>(static_cast<int32_t>(x))
2349 Relocate_functions
<64, false>::rela32(view
, object
, psymval
, addend
);
2352 case elfcpp::R_X86_64_PC32
:
2353 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
2357 case elfcpp::R_X86_64_16
:
2358 Relocate_functions
<64, false>::rela16(view
, object
, psymval
, addend
);
2361 case elfcpp::R_X86_64_PC16
:
2362 Relocate_functions
<64, false>::pcrela16(view
, object
, psymval
, addend
,
2366 case elfcpp::R_X86_64_8
:
2367 Relocate_functions
<64, false>::rela8(view
, object
, psymval
, addend
);
2370 case elfcpp::R_X86_64_PC8
:
2371 Relocate_functions
<64, false>::pcrela8(view
, object
, psymval
, addend
,
2375 case elfcpp::R_X86_64_PLT32
:
2376 gold_assert(gsym
== NULL
2377 || gsym
->has_plt_offset()
2378 || gsym
->final_value_is_known()
2379 || (gsym
->is_defined()
2380 && !gsym
->is_from_dynobj()
2381 && !gsym
->is_preemptible()));
2382 // Note: while this code looks the same as for R_X86_64_PC32, it
2383 // behaves differently because psymval was set to point to
2384 // the PLT entry, rather than the symbol, in Scan::global().
2385 Relocate_functions
<64, false>::pcrela32(view
, object
, psymval
, addend
,
2389 case elfcpp::R_X86_64_PLTOFF64
:
2392 gold_assert(gsym
->has_plt_offset()
2393 || gsym
->final_value_is_known());
2394 elfcpp::Elf_types
<64>::Elf_Addr got_address
;
2395 got_address
= target
->got_section(NULL
, NULL
)->address();
2396 Relocate_functions
<64, false>::rela64(view
, object
, psymval
,
2397 addend
- got_address
);
2400 case elfcpp::R_X86_64_GOT32
:
2401 gold_assert(have_got_offset
);
2402 Relocate_functions
<64, false>::rela32(view
, got_offset
, addend
);
2405 case elfcpp::R_X86_64_GOTPC32
:
2408 elfcpp::Elf_types
<64>::Elf_Addr value
;
2409 value
= target
->got_plt_section()->address();
2410 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
2414 case elfcpp::R_X86_64_GOT64
:
2415 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2416 // Since we always add a PLT entry, this is equivalent.
2417 case elfcpp::R_X86_64_GOTPLT64
:
2418 gold_assert(have_got_offset
);
2419 Relocate_functions
<64, false>::rela64(view
, got_offset
, addend
);
2422 case elfcpp::R_X86_64_GOTPC64
:
2425 elfcpp::Elf_types
<64>::Elf_Addr value
;
2426 value
= target
->got_plt_section()->address();
2427 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
2431 case elfcpp::R_X86_64_GOTOFF64
:
2433 elfcpp::Elf_types
<64>::Elf_Addr value
;
2434 value
= (psymval
->value(object
, 0)
2435 - target
->got_plt_section()->address());
2436 Relocate_functions
<64, false>::rela64(view
, value
, addend
);
2440 case elfcpp::R_X86_64_GOTPCREL
:
2442 gold_assert(have_got_offset
);
2443 elfcpp::Elf_types
<64>::Elf_Addr value
;
2444 value
= target
->got_plt_section()->address() + got_offset
;
2445 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
2449 case elfcpp::R_X86_64_GOTPCREL64
:
2451 gold_assert(have_got_offset
);
2452 elfcpp::Elf_types
<64>::Elf_Addr value
;
2453 value
= target
->got_plt_section()->address() + got_offset
;
2454 Relocate_functions
<64, false>::pcrela64(view
, value
, addend
, address
);
2458 case elfcpp::R_X86_64_COPY
:
2459 case elfcpp::R_X86_64_GLOB_DAT
:
2460 case elfcpp::R_X86_64_JUMP_SLOT
:
2461 case elfcpp::R_X86_64_RELATIVE
:
2462 case elfcpp::R_X86_64_IRELATIVE
:
2463 // These are outstanding tls relocs, which are unexpected when linking
2464 case elfcpp::R_X86_64_TPOFF64
:
2465 case elfcpp::R_X86_64_DTPMOD64
:
2466 case elfcpp::R_X86_64_TLSDESC
:
2467 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2468 _("unexpected reloc %u in object file"),
2472 // These are initial tls relocs, which are expected when linking
2473 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
2474 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
2475 case elfcpp::R_X86_64_TLSDESC_CALL
:
2476 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
2477 case elfcpp::R_X86_64_DTPOFF32
:
2478 case elfcpp::R_X86_64_DTPOFF64
:
2479 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
2480 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
2481 this->relocate_tls(relinfo
, target
, relnum
, rela
, r_type
, gsym
, psymval
,
2482 view
, address
, view_size
);
2485 case elfcpp::R_X86_64_SIZE32
:
2486 case elfcpp::R_X86_64_SIZE64
:
2488 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2489 _("unsupported reloc %u"),
2497 // Perform a TLS relocation.
2500 Target_x86_64::Relocate::relocate_tls(const Relocate_info
<64, false>* relinfo
,
2501 Target_x86_64
* target
,
2503 const elfcpp::Rela
<64, false>& rela
,
2504 unsigned int r_type
,
2505 const Sized_symbol
<64>* gsym
,
2506 const Symbol_value
<64>* psymval
,
2507 unsigned char* view
,
2508 elfcpp::Elf_types
<64>::Elf_Addr address
,
2509 section_size_type view_size
)
2511 Output_segment
* tls_segment
= relinfo
->layout
->tls_segment();
2513 const Sized_relobj
<64, false>* object
= relinfo
->object
;
2514 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
2515 elfcpp::Shdr
<64, false> data_shdr(relinfo
->data_shdr
);
2516 bool is_executable
= (data_shdr
.get_sh_flags() & elfcpp::SHF_EXECINSTR
) != 0;
2518 elfcpp::Elf_types
<64>::Elf_Addr value
= psymval
->value(relinfo
->object
, 0);
2520 const bool is_final
= (gsym
== NULL
2521 ? !parameters
->options().shared()
2522 : gsym
->final_value_is_known());
2523 tls::Tls_optimization optimized_type
2524 = Target_x86_64::optimize_tls_reloc(is_final
, r_type
);
2527 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
2528 if (!is_executable
&& optimized_type
== tls::TLSOPT_TO_LE
)
2530 // If this code sequence is used in a non-executable section,
2531 // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
2532 // on the assumption that it's being used by itself in a debug
2533 // section. Therefore, in the unlikely event that the code
2534 // sequence appears in a non-executable section, we simply
2535 // leave it unoptimized.
2536 optimized_type
= tls::TLSOPT_NONE
;
2538 if (optimized_type
== tls::TLSOPT_TO_LE
)
2540 gold_assert(tls_segment
!= NULL
);
2541 this->tls_gd_to_le(relinfo
, relnum
, tls_segment
,
2542 rela
, r_type
, value
, view
,
2548 unsigned int got_type
= (optimized_type
== tls::TLSOPT_TO_IE
2549 ? GOT_TYPE_TLS_OFFSET
2550 : GOT_TYPE_TLS_PAIR
);
2551 unsigned int got_offset
;
2554 gold_assert(gsym
->has_got_offset(got_type
));
2555 got_offset
= gsym
->got_offset(got_type
) - target
->got_size();
2559 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
2560 gold_assert(object
->local_has_got_offset(r_sym
, got_type
));
2561 got_offset
= (object
->local_got_offset(r_sym
, got_type
)
2562 - target
->got_size());
2564 if (optimized_type
== tls::TLSOPT_TO_IE
)
2566 gold_assert(tls_segment
!= NULL
);
2567 value
= target
->got_plt_section()->address() + got_offset
;
2568 this->tls_gd_to_ie(relinfo
, relnum
, tls_segment
, rela
, r_type
,
2569 value
, view
, address
, view_size
);
2572 else if (optimized_type
== tls::TLSOPT_NONE
)
2574 // Relocate the field with the offset of the pair of GOT
2576 value
= target
->got_plt_section()->address() + got_offset
;
2577 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
,
2582 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2583 _("unsupported reloc %u"), r_type
);
2586 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
2587 case elfcpp::R_X86_64_TLSDESC_CALL
:
2588 if (!is_executable
&& optimized_type
== tls::TLSOPT_TO_LE
)
2590 // See above comment for R_X86_64_TLSGD.
2591 optimized_type
= tls::TLSOPT_NONE
;
2593 if (optimized_type
== tls::TLSOPT_TO_LE
)
2595 gold_assert(tls_segment
!= NULL
);
2596 this->tls_desc_gd_to_le(relinfo
, relnum
, tls_segment
,
2597 rela
, r_type
, value
, view
,
2603 unsigned int got_type
= (optimized_type
== tls::TLSOPT_TO_IE
2604 ? GOT_TYPE_TLS_OFFSET
2605 : GOT_TYPE_TLS_DESC
);
2606 unsigned int got_offset
= 0;
2607 if (r_type
== elfcpp::R_X86_64_GOTPC32_TLSDESC
2608 && optimized_type
== tls::TLSOPT_NONE
)
2610 // We created GOT entries in the .got.tlsdesc portion of
2611 // the .got.plt section, but the offset stored in the
2612 // symbol is the offset within .got.tlsdesc.
2613 got_offset
= (target
->got_size()
2614 + target
->got_plt_section()->data_size());
2618 gold_assert(gsym
->has_got_offset(got_type
));
2619 got_offset
+= gsym
->got_offset(got_type
) - target
->got_size();
2623 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
2624 gold_assert(object
->local_has_got_offset(r_sym
, got_type
));
2625 got_offset
+= (object
->local_got_offset(r_sym
, got_type
)
2626 - target
->got_size());
2628 if (optimized_type
== tls::TLSOPT_TO_IE
)
2630 gold_assert(tls_segment
!= NULL
);
2631 value
= target
->got_plt_section()->address() + got_offset
;
2632 this->tls_desc_gd_to_ie(relinfo
, relnum
, tls_segment
,
2633 rela
, r_type
, value
, view
, address
,
2637 else if (optimized_type
== tls::TLSOPT_NONE
)
2639 if (r_type
== elfcpp::R_X86_64_GOTPC32_TLSDESC
)
2641 // Relocate the field with the offset of the pair of GOT
2643 value
= target
->got_plt_section()->address() + got_offset
;
2644 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
,
2650 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2651 _("unsupported reloc %u"), r_type
);
2654 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
2655 if (!is_executable
&& optimized_type
== tls::TLSOPT_TO_LE
)
2657 // See above comment for R_X86_64_TLSGD.
2658 optimized_type
= tls::TLSOPT_NONE
;
2660 if (optimized_type
== tls::TLSOPT_TO_LE
)
2662 gold_assert(tls_segment
!= NULL
);
2663 this->tls_ld_to_le(relinfo
, relnum
, tls_segment
, rela
, r_type
,
2664 value
, view
, view_size
);
2667 else if (optimized_type
== tls::TLSOPT_NONE
)
2669 // Relocate the field with the offset of the GOT entry for
2670 // the module index.
2671 unsigned int got_offset
;
2672 got_offset
= (target
->got_mod_index_entry(NULL
, NULL
, NULL
)
2673 - target
->got_size());
2674 value
= target
->got_plt_section()->address() + got_offset
;
2675 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
,
2679 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2680 _("unsupported reloc %u"), r_type
);
2683 case elfcpp::R_X86_64_DTPOFF32
:
2684 // This relocation type is used in debugging information.
2685 // In that case we need to not optimize the value. If the
2686 // section is not executable, then we assume we should not
2687 // optimize this reloc. See comments above for R_X86_64_TLSGD,
2688 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
2690 if (optimized_type
== tls::TLSOPT_TO_LE
&& is_executable
)
2692 gold_assert(tls_segment
!= NULL
);
2693 value
-= tls_segment
->memsz();
2695 Relocate_functions
<64, false>::rela32(view
, value
, addend
);
2698 case elfcpp::R_X86_64_DTPOFF64
:
2699 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
2700 if (optimized_type
== tls::TLSOPT_TO_LE
&& is_executable
)
2702 gold_assert(tls_segment
!= NULL
);
2703 value
-= tls_segment
->memsz();
2705 Relocate_functions
<64, false>::rela64(view
, value
, addend
);
2708 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
2709 if (optimized_type
== tls::TLSOPT_TO_LE
)
2711 gold_assert(tls_segment
!= NULL
);
2712 Target_x86_64::Relocate::tls_ie_to_le(relinfo
, relnum
, tls_segment
,
2713 rela
, r_type
, value
, view
,
2717 else if (optimized_type
== tls::TLSOPT_NONE
)
2719 // Relocate the field with the offset of the GOT entry for
2720 // the tp-relative offset of the symbol.
2721 unsigned int got_offset
;
2724 gold_assert(gsym
->has_got_offset(GOT_TYPE_TLS_OFFSET
));
2725 got_offset
= (gsym
->got_offset(GOT_TYPE_TLS_OFFSET
)
2726 - target
->got_size());
2730 unsigned int r_sym
= elfcpp::elf_r_sym
<64>(rela
.get_r_info());
2731 gold_assert(object
->local_has_got_offset(r_sym
,
2732 GOT_TYPE_TLS_OFFSET
));
2733 got_offset
= (object
->local_got_offset(r_sym
, GOT_TYPE_TLS_OFFSET
)
2734 - target
->got_size());
2736 value
= target
->got_plt_section()->address() + got_offset
;
2737 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
2740 gold_error_at_location(relinfo
, relnum
, rela
.get_r_offset(),
2741 _("unsupported reloc type %u"),
2745 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
2746 value
-= tls_segment
->memsz();
2747 Relocate_functions
<64, false>::rela32(view
, value
, addend
);
2752 // Do a relocation in which we convert a TLS General-Dynamic to an
2756 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info
<64, false>* relinfo
,
2759 const elfcpp::Rela
<64, false>& rela
,
2761 elfcpp::Elf_types
<64>::Elf_Addr value
,
2762 unsigned char* view
,
2763 elfcpp::Elf_types
<64>::Elf_Addr address
,
2764 section_size_type view_size
)
2766 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2767 // .word 0x6666; rex64; call __tls_get_addr
2768 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2770 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
2771 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
2773 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2774 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
2775 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2776 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
2778 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2780 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
2781 Relocate_functions
<64, false>::pcrela32(view
+ 8, value
, addend
- 8, address
);
2783 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2785 this->skip_call_tls_get_addr_
= true;
2788 // Do a relocation in which we convert a TLS General-Dynamic to a
2792 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info
<64, false>* relinfo
,
2794 Output_segment
* tls_segment
,
2795 const elfcpp::Rela
<64, false>& rela
,
2797 elfcpp::Elf_types
<64>::Elf_Addr value
,
2798 unsigned char* view
,
2799 section_size_type view_size
)
2801 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2802 // .word 0x6666; rex64; call __tls_get_addr
2803 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2805 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -4);
2806 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 12);
2808 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2809 (memcmp(view
- 4, "\x66\x48\x8d\x3d", 4) == 0));
2810 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2811 (memcmp(view
+ 4, "\x66\x66\x48\xe8", 4) == 0));
2813 memcpy(view
- 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2815 value
-= tls_segment
->memsz();
2816 Relocate_functions
<64, false>::rela32(view
+ 8, value
, 0);
2818 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2820 this->skip_call_tls_get_addr_
= true;
2823 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2826 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2827 const Relocate_info
<64, false>* relinfo
,
2830 const elfcpp::Rela
<64, false>& rela
,
2831 unsigned int r_type
,
2832 elfcpp::Elf_types
<64>::Elf_Addr value
,
2833 unsigned char* view
,
2834 elfcpp::Elf_types
<64>::Elf_Addr address
,
2835 section_size_type view_size
)
2837 if (r_type
== elfcpp::R_X86_64_GOTPC32_TLSDESC
)
2839 // leaq foo@tlsdesc(%rip), %rax
2840 // ==> movq foo@gottpoff(%rip), %rax
2841 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
2842 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
2843 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2844 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x05);
2846 const elfcpp::Elf_Xword addend
= rela
.get_r_addend();
2847 Relocate_functions
<64, false>::pcrela32(view
, value
, addend
, address
);
2851 // call *foo@tlscall(%rax)
2853 gold_assert(r_type
== elfcpp::R_X86_64_TLSDESC_CALL
);
2854 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 2);
2855 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2856 view
[0] == 0xff && view
[1] == 0x10);
2862 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2865 Target_x86_64::Relocate::tls_desc_gd_to_le(
2866 const Relocate_info
<64, false>* relinfo
,
2868 Output_segment
* tls_segment
,
2869 const elfcpp::Rela
<64, false>& rela
,
2870 unsigned int r_type
,
2871 elfcpp::Elf_types
<64>::Elf_Addr value
,
2872 unsigned char* view
,
2873 section_size_type view_size
)
2875 if (r_type
== elfcpp::R_X86_64_GOTPC32_TLSDESC
)
2877 // leaq foo@tlsdesc(%rip), %rax
2878 // ==> movq foo@tpoff, %rax
2879 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
2880 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
2881 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2882 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x05);
2885 value
-= tls_segment
->memsz();
2886 Relocate_functions
<64, false>::rela32(view
, value
, 0);
2890 // call *foo@tlscall(%rax)
2892 gold_assert(r_type
== elfcpp::R_X86_64_TLSDESC_CALL
);
2893 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 2);
2894 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2895 view
[0] == 0xff && view
[1] == 0x10);
2902 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info
<64, false>* relinfo
,
2905 const elfcpp::Rela
<64, false>& rela
,
2907 elfcpp::Elf_types
<64>::Elf_Addr
,
2908 unsigned char* view
,
2909 section_size_type view_size
)
2911 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2912 // ... leq foo@dtpoff(%rax),%reg
2913 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2915 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
2916 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 9);
2918 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(),
2919 view
[-3] == 0x48 && view
[-2] == 0x8d && view
[-1] == 0x3d);
2921 tls::check_tls(relinfo
, relnum
, rela
.get_r_offset(), view
[4] == 0xe8);
2923 memcpy(view
- 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2925 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2927 this->skip_call_tls_get_addr_
= true;
2930 // Do a relocation in which we convert a TLS Initial-Exec to a
2934 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info
<64, false>* relinfo
,
2936 Output_segment
* tls_segment
,
2937 const elfcpp::Rela
<64, false>& rela
,
2939 elfcpp::Elf_types
<64>::Elf_Addr value
,
2940 unsigned char* view
,
2941 section_size_type view_size
)
2943 // We need to examine the opcodes to figure out which instruction we
2946 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
2947 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
2949 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, -3);
2950 tls::check_range(relinfo
, relnum
, rela
.get_r_offset(), view_size
, 4);
2952 unsigned char op1
= view
[-3];
2953 unsigned char op2
= view
[-2];
2954 unsigned char op3
= view
[-1];
2955 unsigned char reg
= op3
>> 3;
2963 view
[-1] = 0xc0 | reg
;
2967 // Special handling for %rsp.
2971 view
[-1] = 0xc0 | reg
;
2979 view
[-1] = 0x80 | reg
| (reg
<< 3);
2982 value
-= tls_segment
->memsz();
2983 Relocate_functions
<64, false>::rela32(view
, value
, 0);
2986 // Relocate section data.
2989 Target_x86_64::relocate_section(
2990 const Relocate_info
<64, false>* relinfo
,
2991 unsigned int sh_type
,
2992 const unsigned char* prelocs
,
2994 Output_section
* output_section
,
2995 bool needs_special_offset_handling
,
2996 unsigned char* view
,
2997 elfcpp::Elf_types
<64>::Elf_Addr address
,
2998 section_size_type view_size
,
2999 const Reloc_symbol_changes
* reloc_symbol_changes
)
3001 gold_assert(sh_type
== elfcpp::SHT_RELA
);
3003 gold::relocate_section
<64, false, Target_x86_64
, elfcpp::SHT_RELA
,
3004 Target_x86_64::Relocate
>(
3010 needs_special_offset_handling
,
3014 reloc_symbol_changes
);
3017 // Return the size of a relocation while scanning during a relocatable
3021 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
3022 unsigned int r_type
,
3027 case elfcpp::R_X86_64_NONE
:
3028 case elfcpp::R_X86_64_GNU_VTINHERIT
:
3029 case elfcpp::R_X86_64_GNU_VTENTRY
:
3030 case elfcpp::R_X86_64_TLSGD
: // Global-dynamic
3031 case elfcpp::R_X86_64_GOTPC32_TLSDESC
: // Global-dynamic (from ~oliva url)
3032 case elfcpp::R_X86_64_TLSDESC_CALL
:
3033 case elfcpp::R_X86_64_TLSLD
: // Local-dynamic
3034 case elfcpp::R_X86_64_DTPOFF32
:
3035 case elfcpp::R_X86_64_DTPOFF64
:
3036 case elfcpp::R_X86_64_GOTTPOFF
: // Initial-exec
3037 case elfcpp::R_X86_64_TPOFF32
: // Local-exec
3040 case elfcpp::R_X86_64_64
:
3041 case elfcpp::R_X86_64_PC64
:
3042 case elfcpp::R_X86_64_GOTOFF64
:
3043 case elfcpp::R_X86_64_GOTPC64
:
3044 case elfcpp::R_X86_64_PLTOFF64
:
3045 case elfcpp::R_X86_64_GOT64
:
3046 case elfcpp::R_X86_64_GOTPCREL64
:
3047 case elfcpp::R_X86_64_GOTPCREL
:
3048 case elfcpp::R_X86_64_GOTPLT64
:
3051 case elfcpp::R_X86_64_32
:
3052 case elfcpp::R_X86_64_32S
:
3053 case elfcpp::R_X86_64_PC32
:
3054 case elfcpp::R_X86_64_PLT32
:
3055 case elfcpp::R_X86_64_GOTPC32
:
3056 case elfcpp::R_X86_64_GOT32
:
3059 case elfcpp::R_X86_64_16
:
3060 case elfcpp::R_X86_64_PC16
:
3063 case elfcpp::R_X86_64_8
:
3064 case elfcpp::R_X86_64_PC8
:
3067 case elfcpp::R_X86_64_COPY
:
3068 case elfcpp::R_X86_64_GLOB_DAT
:
3069 case elfcpp::R_X86_64_JUMP_SLOT
:
3070 case elfcpp::R_X86_64_RELATIVE
:
3071 case elfcpp::R_X86_64_IRELATIVE
:
3072 // These are outstanding tls relocs, which are unexpected when linking
3073 case elfcpp::R_X86_64_TPOFF64
:
3074 case elfcpp::R_X86_64_DTPMOD64
:
3075 case elfcpp::R_X86_64_TLSDESC
:
3076 object
->error(_("unexpected reloc %u in object file"), r_type
);
3079 case elfcpp::R_X86_64_SIZE32
:
3080 case elfcpp::R_X86_64_SIZE64
:
3082 object
->error(_("unsupported reloc %u against local symbol"), r_type
);
3087 // Scan the relocs during a relocatable link.
3090 Target_x86_64::scan_relocatable_relocs(Symbol_table
* symtab
,
3092 Sized_relobj
<64, false>* object
,
3093 unsigned int data_shndx
,
3094 unsigned int sh_type
,
3095 const unsigned char* prelocs
,
3097 Output_section
* output_section
,
3098 bool needs_special_offset_handling
,
3099 size_t local_symbol_count
,
3100 const unsigned char* plocal_symbols
,
3101 Relocatable_relocs
* rr
)
3103 gold_assert(sh_type
== elfcpp::SHT_RELA
);
3105 typedef gold::Default_scan_relocatable_relocs
<elfcpp::SHT_RELA
,
3106 Relocatable_size_for_reloc
> Scan_relocatable_relocs
;
3108 gold::scan_relocatable_relocs
<64, false, elfcpp::SHT_RELA
,
3109 Scan_relocatable_relocs
>(
3117 needs_special_offset_handling
,
3123 // Relocate a section during a relocatable link.
3126 Target_x86_64::relocate_for_relocatable(
3127 const Relocate_info
<64, false>* relinfo
,
3128 unsigned int sh_type
,
3129 const unsigned char* prelocs
,
3131 Output_section
* output_section
,
3132 off_t offset_in_output_section
,
3133 const Relocatable_relocs
* rr
,
3134 unsigned char* view
,
3135 elfcpp::Elf_types
<64>::Elf_Addr view_address
,
3136 section_size_type view_size
,
3137 unsigned char* reloc_view
,
3138 section_size_type reloc_view_size
)
3140 gold_assert(sh_type
== elfcpp::SHT_RELA
);
3142 gold::relocate_for_relocatable
<64, false, elfcpp::SHT_RELA
>(
3147 offset_in_output_section
,
3156 // Return the value to use for a dynamic which requires special
3157 // treatment. This is how we support equality comparisons of function
3158 // pointers across shared library boundaries, as described in the
3159 // processor specific ABI supplement.
3162 Target_x86_64::do_dynsym_value(const Symbol
* gsym
) const
3164 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
3165 return this->plt_section()->address() + gsym
->plt_offset();
3168 // Return a string used to fill a code section with nops to take up
3169 // the specified length.
3172 Target_x86_64::do_code_fill(section_size_type length
) const
3176 // Build a jmpq instruction to skip over the bytes.
3177 unsigned char jmp
[5];
3179 elfcpp::Swap_unaligned
<32, false>::writeval(jmp
+ 1, length
- 5);
3180 return (std::string(reinterpret_cast<char*>(&jmp
[0]), 5)
3181 + std::string(length
- 5, '\0'));
3184 // Nop sequences of various lengths.
3185 const char nop1
[1] = { 0x90 }; // nop
3186 const char nop2
[2] = { 0x66, 0x90 }; // xchg %ax %ax
3187 const char nop3
[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax)
3188 const char nop4
[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax)
3189 const char nop5
[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1)
3191 const char nop6
[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1)
3193 const char nop7
[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax)
3195 const char nop8
[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1)
3196 0x00, 0x00, 0x00, 0x00 };
3197 const char nop9
[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1)
3198 0x00, 0x00, 0x00, 0x00,
3200 const char nop10
[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
3201 0x84, 0x00, 0x00, 0x00,
3203 const char nop11
[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
3204 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3206 const char nop12
[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
3207 0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
3208 0x00, 0x00, 0x00, 0x00 };
3209 const char nop13
[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3210 0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
3211 0x00, 0x00, 0x00, 0x00,
3213 const char nop14
[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3214 0x66, 0x2e, 0x0f, 0x1f, // data16
3215 0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3217 const char nop15
[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3218 0x66, 0x66, 0x2e, 0x0f, // data16; data16
3219 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3222 const char* nops
[16] = {
3224 nop1
, nop2
, nop3
, nop4
, nop5
, nop6
, nop7
,
3225 nop8
, nop9
, nop10
, nop11
, nop12
, nop13
, nop14
, nop15
3228 return std::string(nops
[length
], length
);
3231 // Return the addend to use for a target specific relocation. The
3232 // only target specific relocation is R_X86_64_TLSDESC for a local
3233 // symbol. We want to set the addend is the offset of the local
3234 // symbol in the TLS segment.
3237 Target_x86_64::do_reloc_addend(void* arg
, unsigned int r_type
,
3240 gold_assert(r_type
== elfcpp::R_X86_64_TLSDESC
);
3241 uintptr_t intarg
= reinterpret_cast<uintptr_t>(arg
);
3242 gold_assert(intarg
< this->tlsdesc_reloc_info_
.size());
3243 const Tlsdesc_info
& ti(this->tlsdesc_reloc_info_
[intarg
]);
3244 const Symbol_value
<64>* psymval
= ti
.object
->local_symbol(ti
.r_sym
);
3245 gold_assert(psymval
->is_tls_symbol());
3246 // The value of a TLS symbol is the offset in the TLS segment.
3247 return psymval
->value(ti
.object
, 0);
3250 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3251 // compiled with -fsplit-stack. The function calls non-split-stack
3252 // code. We have to change the function so that it always ensures
3253 // that it has enough stack space to run some random function.
3256 Target_x86_64::do_calls_non_split(Relobj
* object
, unsigned int shndx
,
3257 section_offset_type fnoffset
,
3258 section_size_type fnsize
,
3259 unsigned char* view
,
3260 section_size_type view_size
,
3262 std::string
* to
) const
3264 // The function starts with a comparison of the stack pointer and a
3265 // field in the TCB. This is followed by a jump.
3268 if (this->match_view(view
, view_size
, fnoffset
, "\x64\x48\x3b\x24\x25", 5)
3271 // We will call __morestack if the carry flag is set after this
3272 // comparison. We turn the comparison into an stc instruction
3274 view
[fnoffset
] = '\xf9';
3275 this->set_view_to_nop(view
, view_size
, fnoffset
+ 1, 8);
3277 // lea NN(%rsp),%r10
3278 // lea NN(%rsp),%r11
3279 else if ((this->match_view(view
, view_size
, fnoffset
,
3280 "\x4c\x8d\x94\x24", 4)
3281 || this->match_view(view
, view_size
, fnoffset
,
3282 "\x4c\x8d\x9c\x24", 4))
3285 // This is loading an offset from the stack pointer for a
3286 // comparison. The offset is negative, so we decrease the
3287 // offset by the amount of space we need for the stack. This
3288 // means we will avoid calling __morestack if there happens to
3289 // be plenty of space on the stack already.
3290 unsigned char* pval
= view
+ fnoffset
+ 4;
3291 uint32_t val
= elfcpp::Swap_unaligned
<32, false>::readval(pval
);
3292 val
-= parameters
->options().split_stack_adjust_size();
3293 elfcpp::Swap_unaligned
<32, false>::writeval(pval
, val
);
3297 if (!object
->has_no_split_stack())
3298 object
->error(_("failed to match split-stack sequence at "
3299 "section %u offset %0zx"),
3300 shndx
, static_cast<size_t>(fnoffset
));
3304 // We have to change the function so that it calls
3305 // __morestack_non_split instead of __morestack. The former will
3306 // allocate additional stack space.
3307 *from
= "__morestack";
3308 *to
= "__morestack_non_split";
3311 // The selector for x86_64 object files.
3313 class Target_selector_x86_64
: public Target_selector_freebsd
3316 Target_selector_x86_64()
3317 : Target_selector_freebsd(elfcpp::EM_X86_64
, 64, false, "elf64-x86-64",
3318 "elf64-x86-64-freebsd")
3322 do_instantiate_target()
3323 { return new Target_x86_64(); }
3327 Target_selector_x86_64 target_selector_x86_64
;
3329 } // End anonymous namespace.