1 // x86_64.cc -- x86_64 target support for gold.
3 // Copyright 2006, 2007, 2008, 2009 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 class Output_data_plt_x86_64;
51 // The x86_64 target class.
53 // http://www.x86-64.org/documentation/abi.pdf
54 // TLS info comes from
55 // http://people.redhat.com/drepper/tls.pdf
56 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
58 class Target_x86_64 : public Target_freebsd<64, false>
61 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
62 // uses only Elf64_Rela relocation entries with explicit addends."
63 typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
66 : Target_freebsd<64, false>(&x86_64_info),
67 got_(NULL), plt_(NULL), got_plt_(NULL), global_offset_table_(NULL),
68 rela_dyn_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
69 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
70 tls_base_symbol_defined_(false)
73 // This function should be defined in targets that can use relocation
74 // types to determine (implemented in local_reloc_may_be_function_pointer
75 // and global_reloc_may_be_function_pointer)
76 // if a function's pointer is taken. ICF uses this in safe mode to only
77 // fold those functions whose pointer is defintely not taken. For x86_64
78 // pie binaries, safe ICF cannot be done by looking at relocation types.
80 can_check_for_function_pointers() const
81 { return !parameters->options().pie(); }
83 // Hook for a new output section.
85 do_new_output_section(Output_section*) const;
87 // Scan the relocations to look for symbol adjustments.
89 gc_process_relocs(Symbol_table* symtab,
91 Sized_relobj<64, false>* object,
92 unsigned int data_shndx,
94 const unsigned char* prelocs,
96 Output_section* output_section,
97 bool needs_special_offset_handling,
98 size_t local_symbol_count,
99 const unsigned char* plocal_symbols);
101 // Scan the relocations to look for symbol adjustments.
103 scan_relocs(Symbol_table* symtab,
105 Sized_relobj<64, false>* object,
106 unsigned int data_shndx,
107 unsigned int sh_type,
108 const unsigned char* prelocs,
110 Output_section* output_section,
111 bool needs_special_offset_handling,
112 size_t local_symbol_count,
113 const unsigned char* plocal_symbols);
115 // Finalize the sections.
117 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
119 // Return the value to use for a dynamic which requires special
122 do_dynsym_value(const Symbol*) const;
124 // Relocate a section.
126 relocate_section(const Relocate_info<64, false>*,
127 unsigned int sh_type,
128 const unsigned char* prelocs,
130 Output_section* output_section,
131 bool needs_special_offset_handling,
133 elfcpp::Elf_types<64>::Elf_Addr view_address,
134 section_size_type view_size,
135 const Reloc_symbol_changes*);
137 // Scan the relocs during a relocatable link.
139 scan_relocatable_relocs(Symbol_table* symtab,
141 Sized_relobj<64, false>* object,
142 unsigned int data_shndx,
143 unsigned int sh_type,
144 const unsigned char* prelocs,
146 Output_section* output_section,
147 bool needs_special_offset_handling,
148 size_t local_symbol_count,
149 const unsigned char* plocal_symbols,
150 Relocatable_relocs*);
152 // Relocate a section during a relocatable link.
154 relocate_for_relocatable(const Relocate_info<64, false>*,
155 unsigned int sh_type,
156 const unsigned char* prelocs,
158 Output_section* output_section,
159 off_t offset_in_output_section,
160 const Relocatable_relocs*,
162 elfcpp::Elf_types<64>::Elf_Addr view_address,
163 section_size_type view_size,
164 unsigned char* reloc_view,
165 section_size_type reloc_view_size);
167 // Return a string used to fill a code section with nops.
169 do_code_fill(section_size_type length) const;
171 // Return whether SYM is defined by the ABI.
173 do_is_defined_by_abi(const Symbol* sym) const
174 { return strcmp(sym->name(), "__tls_get_addr") == 0; }
176 // Return the symbol index to use for a target specific relocation.
177 // The only target specific relocation is R_X86_64_TLSDESC for a
178 // local symbol, which is an absolute reloc.
180 do_reloc_symbol_index(void*, unsigned int r_type) const
182 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
186 // Return the addend to use for a target specific relocation.
188 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
190 // Adjust -fstack-split code which calls non-stack-split code.
192 do_calls_non_split(Relobj* object, unsigned int shndx,
193 section_offset_type fnoffset, section_size_type fnsize,
194 unsigned char* view, section_size_type view_size,
195 std::string* from, std::string* to) const;
197 // Return the size of the GOT section.
201 gold_assert(this->got_ != NULL);
202 return this->got_->data_size();
205 // Add a new reloc argument, returning the index in the vector.
207 add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym)
209 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
210 return this->tlsdesc_reloc_info_.size() - 1;
214 // The class which scans relocations.
219 : issued_non_pic_error_(false)
223 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
224 Sized_relobj<64, false>* object,
225 unsigned int data_shndx,
226 Output_section* output_section,
227 const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
228 const elfcpp::Sym<64, false>& lsym);
231 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
232 Sized_relobj<64, false>* object,
233 unsigned int data_shndx,
234 Output_section* output_section,
235 const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
239 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
240 Target_x86_64* target,
241 Sized_relobj<64, false>* object,
242 unsigned int data_shndx,
243 Output_section* output_section,
244 const elfcpp::Rela<64, false>& reloc,
246 const elfcpp::Sym<64, false>& lsym);
249 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
250 Target_x86_64* target,
251 Sized_relobj<64, false>* object,
252 unsigned int data_shndx,
253 Output_section* output_section,
254 const elfcpp::Rela<64, false>& reloc,
260 unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
263 unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
267 check_non_pic(Relobj*, unsigned int r_type);
270 possible_function_pointer_reloc(unsigned int r_type);
272 // Whether we have issued an error about a non-PIC compilation.
273 bool issued_non_pic_error_;
276 // The class which implements relocation.
281 : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
286 if (this->skip_call_tls_get_addr_)
288 // FIXME: This needs to specify the location somehow.
289 gold_error(_("missing expected TLS relocation"));
293 // Do a relocation. Return false if the caller should not issue
294 // any warnings about this relocation.
296 relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
297 size_t relnum, const elfcpp::Rela<64, false>&,
298 unsigned int r_type, const Sized_symbol<64>*,
299 const Symbol_value<64>*,
300 unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
304 // Do a TLS relocation.
306 relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
307 size_t relnum, const elfcpp::Rela<64, false>&,
308 unsigned int r_type, const Sized_symbol<64>*,
309 const Symbol_value<64>*,
310 unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
313 // Do a TLS General-Dynamic to Initial-Exec transition.
315 tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
316 Output_segment* tls_segment,
317 const elfcpp::Rela<64, false>&, unsigned int r_type,
318 elfcpp::Elf_types<64>::Elf_Addr value,
320 elfcpp::Elf_types<64>::Elf_Addr,
321 section_size_type view_size);
323 // Do a TLS General-Dynamic to Local-Exec transition.
325 tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
326 Output_segment* tls_segment,
327 const elfcpp::Rela<64, false>&, unsigned int r_type,
328 elfcpp::Elf_types<64>::Elf_Addr value,
330 section_size_type view_size);
332 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
334 tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
335 Output_segment* tls_segment,
336 const elfcpp::Rela<64, false>&, unsigned int r_type,
337 elfcpp::Elf_types<64>::Elf_Addr value,
339 elfcpp::Elf_types<64>::Elf_Addr,
340 section_size_type view_size);
342 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
344 tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
345 Output_segment* tls_segment,
346 const elfcpp::Rela<64, false>&, unsigned int r_type,
347 elfcpp::Elf_types<64>::Elf_Addr value,
349 section_size_type view_size);
351 // Do a TLS Local-Dynamic to Local-Exec transition.
353 tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
354 Output_segment* tls_segment,
355 const elfcpp::Rela<64, false>&, unsigned int r_type,
356 elfcpp::Elf_types<64>::Elf_Addr value,
358 section_size_type view_size);
360 // Do a TLS Initial-Exec to Local-Exec transition.
362 tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
363 Output_segment* tls_segment,
364 const elfcpp::Rela<64, false>&, unsigned int r_type,
365 elfcpp::Elf_types<64>::Elf_Addr value,
367 section_size_type view_size);
369 // This is set if we should skip the next reloc, which should be a
370 // PLT32 reloc against ___tls_get_addr.
371 bool skip_call_tls_get_addr_;
373 // This is set if we see a relocation which could load the address
374 // of the TLS block. Whether we see such a relocation determines
375 // how we handle the R_X86_64_DTPOFF32 relocation, which is used
376 // in debugging sections.
377 bool saw_tls_block_reloc_;
380 // A class which returns the size required for a relocation type,
381 // used while scanning relocs during a relocatable link.
382 class Relocatable_size_for_reloc
386 get_size_for_reloc(unsigned int, Relobj*);
389 // Adjust TLS relocation type based on the options and whether this
390 // is a local symbol.
391 static tls::Tls_optimization
392 optimize_tls_reloc(bool is_final, int r_type);
394 // Get the GOT section, creating it if necessary.
395 Output_data_got<64, false>*
396 got_section(Symbol_table*, Layout*);
398 // Get the GOT PLT section.
400 got_plt_section() const
402 gold_assert(this->got_plt_ != NULL);
403 return this->got_plt_;
406 // Create the PLT section.
408 make_plt_section(Symbol_table* symtab, Layout* layout);
410 // Create a PLT entry for a global symbol.
412 make_plt_entry(Symbol_table*, Layout*, Symbol*);
414 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
416 define_tls_base_symbol(Symbol_table*, Layout*);
418 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
420 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
422 // Create a GOT entry for the TLS module index.
424 got_mod_index_entry(Symbol_table* symtab, Layout* layout,
425 Sized_relobj<64, false>* object);
427 // Get the PLT section.
428 Output_data_plt_x86_64*
431 gold_assert(this->plt_ != NULL);
435 // Get the dynamic reloc section, creating it if necessary.
437 rela_dyn_section(Layout*);
439 // Get the section to use for TLSDESC relocations.
441 rela_tlsdesc_section(Layout*) const;
443 // Add a potential copy relocation.
445 copy_reloc(Symbol_table* symtab, Layout* layout,
446 Sized_relobj<64, false>* object,
447 unsigned int shndx, Output_section* output_section,
448 Symbol* sym, const elfcpp::Rela<64, false>& reloc)
450 this->copy_relocs_.copy_reloc(symtab, layout,
451 symtab->get_sized_symbol<64>(sym),
452 object, shndx, output_section,
453 reloc, this->rela_dyn_section(layout));
456 // Information about this specific target which we pass to the
457 // general Target structure.
458 static const Target::Target_info x86_64_info;
462 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
463 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset
464 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
465 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
468 // This type is used as the argument to the target specific
469 // relocation routines. The only target specific reloc is
470 // R_X86_64_TLSDESC against a local symbol.
473 Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym)
474 : object(a_object), r_sym(a_r_sym)
477 // The object in which the local symbol is defined.
478 Sized_relobj<64, false>* object;
479 // The local symbol index in the object.
484 Output_data_got<64, false>* got_;
486 Output_data_plt_x86_64* plt_;
487 // The GOT PLT section.
488 Output_data_space* got_plt_;
489 // The _GLOBAL_OFFSET_TABLE_ symbol.
490 Symbol* global_offset_table_;
491 // The dynamic reloc section.
492 Reloc_section* rela_dyn_;
493 // Relocs saved to avoid a COPY reloc.
494 Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
495 // Space for variables copied with a COPY reloc.
496 Output_data_space* dynbss_;
497 // Offset of the GOT entry for the TLS module index.
498 unsigned int got_mod_index_offset_;
499 // We handle R_X86_64_TLSDESC against a local symbol as a target
500 // specific relocation. Here we store the object and local symbol
501 // index for the relocation.
502 std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
503 // True if the _TLS_MODULE_BASE_ symbol has been defined.
504 bool tls_base_symbol_defined_;
507 const Target::Target_info Target_x86_64::x86_64_info =
510 false, // is_big_endian
511 elfcpp::EM_X86_64, // machine_code
512 false, // has_make_symbol
513 false, // has_resolve
514 true, // has_code_fill
515 true, // is_default_stack_executable
517 "/lib/ld64.so.1", // program interpreter
518 0x400000, // default_text_segment_address
519 0x1000, // abi_pagesize (overridable by -z max-page-size)
520 0x1000, // common_pagesize (overridable by -z common-page-size)
521 elfcpp::SHN_UNDEF, // small_common_shndx
522 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
523 0, // small_common_section_flags
524 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
525 NULL, // attributes_section
526 NULL // attributes_vendor
529 // This is called when a new output section is created. This is where
530 // we handle the SHF_X86_64_LARGE.
533 Target_x86_64::do_new_output_section(Output_section *os) const
535 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
536 os->set_is_large_section();
539 // Get the GOT section, creating it if necessary.
541 Output_data_got<64, false>*
542 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
544 if (this->got_ == NULL)
546 gold_assert(symtab != NULL && layout != NULL);
548 this->got_ = new Output_data_got<64, false>();
550 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
552 | elfcpp::SHF_WRITE),
553 this->got_, false, true, true, false);
555 this->got_plt_ = new Output_data_space(8, "** GOT PLT");
556 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
558 | elfcpp::SHF_WRITE),
559 this->got_plt_, false, false, false,
562 // The first three entries are reserved.
563 this->got_plt_->set_current_data_size(3 * 8);
565 // Those bytes can go into the relro segment.
566 layout->increase_relro(3 * 8);
568 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
569 this->global_offset_table_ =
570 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
571 Symbol_table::PREDEFINED,
573 0, 0, elfcpp::STT_OBJECT,
575 elfcpp::STV_HIDDEN, 0,
582 // Get the dynamic reloc section, creating it if necessary.
584 Target_x86_64::Reloc_section*
585 Target_x86_64::rela_dyn_section(Layout* layout)
587 if (this->rela_dyn_ == NULL)
589 gold_assert(layout != NULL);
590 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
591 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
592 elfcpp::SHF_ALLOC, this->rela_dyn_, true,
593 false, false, false);
595 return this->rela_dyn_;
598 // A class to handle the PLT data.
600 class Output_data_plt_x86_64 : public Output_section_data
603 typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
605 Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
608 // Add an entry to the PLT.
610 add_entry(Symbol* gsym);
612 // Add the reserved TLSDESC_PLT entry to the PLT.
614 reserve_tlsdesc_entry(unsigned int got_offset)
615 { this->tlsdesc_got_offset_ = got_offset; }
617 // Return true if a TLSDESC_PLT entry has been reserved.
619 has_tlsdesc_entry() const
620 { return this->tlsdesc_got_offset_ != -1U; }
622 // Return the GOT offset for the reserved TLSDESC_PLT entry.
624 get_tlsdesc_got_offset() const
625 { return this->tlsdesc_got_offset_; }
627 // Return the offset of the reserved TLSDESC_PLT entry.
629 get_tlsdesc_plt_offset() const
630 { return (this->count_ + 1) * plt_entry_size; }
632 // Return the .rela.plt section data.
635 { return this->rel_; }
637 // Return where the TLSDESC relocations should go.
639 rela_tlsdesc(Layout*);
643 do_adjust_output_section(Output_section* os);
645 // Write to a map file.
647 do_print_to_mapfile(Mapfile* mapfile) const
648 { mapfile->print_output_data(this, _("** PLT")); }
651 // The size of an entry in the PLT.
652 static const int plt_entry_size = 16;
654 // The first entry in the PLT.
655 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
656 // procedure linkage table for both programs and shared objects."
657 static unsigned char first_plt_entry[plt_entry_size];
659 // Other entries in the PLT for an executable.
660 static unsigned char plt_entry[plt_entry_size];
662 // The reserved TLSDESC entry in the PLT for an executable.
663 static unsigned char tlsdesc_plt_entry[plt_entry_size];
665 // Set the final size.
667 set_final_data_size();
669 // Write out the PLT data.
671 do_write(Output_file*);
673 // The reloc section.
675 // The TLSDESC relocs, if necessary. These must follow the regular
677 Reloc_section* tlsdesc_rel_;
679 Output_data_got<64, false>* got_;
680 // The .got.plt section.
681 Output_data_space* got_plt_;
682 // The number of PLT entries.
684 // Offset of the reserved TLSDESC_GOT entry when needed.
685 unsigned int tlsdesc_got_offset_;
688 // Create the PLT section. The ordinary .got section is an argument,
689 // since we need to refer to the start. We also create our own .got
690 // section just for PLT entries.
692 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
693 Output_data_got<64, false>* got,
694 Output_data_space* got_plt)
695 : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
696 count_(0), tlsdesc_got_offset_(-1U)
698 this->rel_ = new Reloc_section(false);
699 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
700 elfcpp::SHF_ALLOC, this->rel_, true,
701 false, false, false);
705 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
707 os->set_entsize(plt_entry_size);
710 // Add an entry to the PLT.
713 Output_data_plt_x86_64::add_entry(Symbol* gsym)
715 gold_assert(!gsym->has_plt_offset());
717 // Note that when setting the PLT offset we skip the initial
718 // reserved PLT entry.
719 gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
723 section_offset_type got_offset = this->got_plt_->current_data_size();
725 // Every PLT entry needs a GOT entry which points back to the PLT
726 // entry (this will be changed by the dynamic linker, normally
727 // lazily when the function is called).
728 this->got_plt_->set_current_data_size(got_offset + 8);
730 // Every PLT entry needs a reloc.
731 gsym->set_needs_dynsym_entry();
732 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
735 // Note that we don't need to save the symbol. The contents of the
736 // PLT are independent of which symbols are used. The symbols only
737 // appear in the relocations.
740 // Return where the TLSDESC relocations should go, creating it if
741 // necessary. These follow the JUMP_SLOT relocations.
743 Output_data_plt_x86_64::Reloc_section*
744 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
746 if (this->tlsdesc_rel_ == NULL)
748 this->tlsdesc_rel_ = new Reloc_section(false);
749 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
750 elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
751 true, false, false, false);
752 gold_assert(this->tlsdesc_rel_->output_section() ==
753 this->rel_->output_section());
755 return this->tlsdesc_rel_;
758 // Set the final size.
760 Output_data_plt_x86_64::set_final_data_size()
762 unsigned int count = this->count_;
763 if (this->has_tlsdesc_entry())
765 this->set_data_size((count + 1) * plt_entry_size);
768 // The first entry in the PLT for an executable.
770 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
772 // From AMD64 ABI Draft 0.98, page 76
773 0xff, 0x35, // pushq contents of memory address
774 0, 0, 0, 0, // replaced with address of .got + 8
775 0xff, 0x25, // jmp indirect
776 0, 0, 0, 0, // replaced with address of .got + 16
777 0x90, 0x90, 0x90, 0x90 // noop (x4)
780 // Subsequent entries in the PLT for an executable.
782 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
784 // From AMD64 ABI Draft 0.98, page 76
785 0xff, 0x25, // jmpq indirect
786 0, 0, 0, 0, // replaced with address of symbol in .got
787 0x68, // pushq immediate
788 0, 0, 0, 0, // replaced with offset into relocation table
789 0xe9, // jmpq relative
790 0, 0, 0, 0 // replaced with offset to start of .plt
793 // The reserved TLSDESC entry in the PLT for an executable.
795 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
797 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
798 // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
799 0xff, 0x35, // pushq x(%rip)
800 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
801 0xff, 0x25, // jmpq *y(%rip)
802 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
807 // Write out the PLT. This uses the hand-coded instructions above,
808 // and adjusts them as needed. This is specified by the AMD64 ABI.
811 Output_data_plt_x86_64::do_write(Output_file* of)
813 const off_t offset = this->offset();
814 const section_size_type oview_size =
815 convert_to_section_size_type(this->data_size());
816 unsigned char* const oview = of->get_output_view(offset, oview_size);
818 const off_t got_file_offset = this->got_plt_->offset();
819 const section_size_type got_size =
820 convert_to_section_size_type(this->got_plt_->data_size());
821 unsigned char* const got_view = of->get_output_view(got_file_offset,
824 unsigned char* pov = oview;
826 // The base address of the .plt section.
827 elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
828 // The base address of the .got section.
829 elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
830 // The base address of the PLT portion of the .got section,
831 // which is where the GOT pointer will point, and where the
832 // three reserved GOT entries are located.
833 elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
835 memcpy(pov, first_plt_entry, plt_entry_size);
836 // We do a jmp relative to the PC at the end of this instruction.
837 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
839 - (plt_address + 6)));
840 elfcpp::Swap<32, false>::writeval(pov + 8,
842 - (plt_address + 12)));
843 pov += plt_entry_size;
845 unsigned char* got_pov = got_view;
847 memset(got_pov, 0, 24);
850 unsigned int plt_offset = plt_entry_size;
851 unsigned int got_offset = 24;
852 const unsigned int count = this->count_;
853 for (unsigned int plt_index = 0;
856 pov += plt_entry_size,
858 plt_offset += plt_entry_size,
861 // Set and adjust the PLT entry itself.
862 memcpy(pov, plt_entry, plt_entry_size);
863 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
864 (got_address + got_offset
865 - (plt_address + plt_offset
868 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
869 elfcpp::Swap<32, false>::writeval(pov + 12,
870 - (plt_offset + plt_entry_size));
872 // Set the entry in the GOT.
873 elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
876 if (this->has_tlsdesc_entry())
878 // Set and adjust the reserved TLSDESC PLT entry.
879 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
880 memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
881 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
883 - (plt_address + plt_offset
885 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
888 - (plt_address + plt_offset
890 pov += plt_entry_size;
893 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
894 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
896 of->write_output_view(offset, oview_size, oview);
897 of->write_output_view(got_file_offset, got_size, got_view);
900 // Create the PLT section.
903 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
905 if (this->plt_ == NULL)
907 // Create the GOT sections first.
908 this->got_section(symtab, layout);
910 this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
912 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
914 | elfcpp::SHF_EXECINSTR),
915 this->plt_, false, false, false, false);
919 // Return the section for TLSDESC relocations.
921 Target_x86_64::Reloc_section*
922 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
924 return this->plt_section()->rela_tlsdesc(layout);
927 // Create a PLT entry for a global symbol.
930 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
933 if (gsym->has_plt_offset())
936 if (this->plt_ == NULL)
937 this->make_plt_section(symtab, layout);
939 this->plt_->add_entry(gsym);
942 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
945 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
947 if (this->tls_base_symbol_defined_)
950 Output_segment* tls_segment = layout->tls_segment();
951 if (tls_segment != NULL)
953 bool is_exec = parameters->options().output_is_executable();
954 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
955 Symbol_table::PREDEFINED,
959 elfcpp::STV_HIDDEN, 0,
961 ? Symbol::SEGMENT_END
962 : Symbol::SEGMENT_START),
965 this->tls_base_symbol_defined_ = true;
968 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
971 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
974 if (this->plt_ == NULL)
975 this->make_plt_section(symtab, layout);
977 if (!this->plt_->has_tlsdesc_entry())
979 // Allocate the TLSDESC_GOT entry.
980 Output_data_got<64, false>* got = this->got_section(symtab, layout);
981 unsigned int got_offset = got->add_constant(0);
983 // Allocate the TLSDESC_PLT entry.
984 this->plt_->reserve_tlsdesc_entry(got_offset);
988 // Create a GOT entry for the TLS module index.
991 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
992 Sized_relobj<64, false>* object)
994 if (this->got_mod_index_offset_ == -1U)
996 gold_assert(symtab != NULL && layout != NULL && object != NULL);
997 Reloc_section* rela_dyn = this->rela_dyn_section(layout);
998 Output_data_got<64, false>* got = this->got_section(symtab, layout);
999 unsigned int got_offset = got->add_constant(0);
1000 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1002 got->add_constant(0);
1003 this->got_mod_index_offset_ = got_offset;
1005 return this->got_mod_index_offset_;
1008 // Optimize the TLS relocation type based on what we know about the
1009 // symbol. IS_FINAL is true if the final address of this symbol is
1010 // known at link time.
1012 tls::Tls_optimization
1013 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1015 // If we are generating a shared library, then we can't do anything
1017 if (parameters->options().shared())
1018 return tls::TLSOPT_NONE;
1022 case elfcpp::R_X86_64_TLSGD:
1023 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1024 case elfcpp::R_X86_64_TLSDESC_CALL:
1025 // These are General-Dynamic which permits fully general TLS
1026 // access. Since we know that we are generating an executable,
1027 // we can convert this to Initial-Exec. If we also know that
1028 // this is a local symbol, we can further switch to Local-Exec.
1030 return tls::TLSOPT_TO_LE;
1031 return tls::TLSOPT_TO_IE;
1033 case elfcpp::R_X86_64_TLSLD:
1034 // This is Local-Dynamic, which refers to a local symbol in the
1035 // dynamic TLS block. Since we know that we generating an
1036 // executable, we can switch to Local-Exec.
1037 return tls::TLSOPT_TO_LE;
1039 case elfcpp::R_X86_64_DTPOFF32:
1040 case elfcpp::R_X86_64_DTPOFF64:
1041 // Another Local-Dynamic reloc.
1042 return tls::TLSOPT_TO_LE;
1044 case elfcpp::R_X86_64_GOTTPOFF:
1045 // These are Initial-Exec relocs which get the thread offset
1046 // from the GOT. If we know that we are linking against the
1047 // local symbol, we can switch to Local-Exec, which links the
1048 // thread offset into the instruction.
1050 return tls::TLSOPT_TO_LE;
1051 return tls::TLSOPT_NONE;
1053 case elfcpp::R_X86_64_TPOFF32:
1054 // When we already have Local-Exec, there is nothing further we
1056 return tls::TLSOPT_NONE;
1063 // Report an unsupported relocation against a local symbol.
1066 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
1067 unsigned int r_type)
1069 gold_error(_("%s: unsupported reloc %u against local symbol"),
1070 object->name().c_str(), r_type);
1073 // We are about to emit a dynamic relocation of type R_TYPE. If the
1074 // dynamic linker does not support it, issue an error. The GNU linker
1075 // only issues a non-PIC error for an allocated read-only section.
1076 // Here we know the section is allocated, but we don't know that it is
1077 // read-only. But we check for all the relocation types which the
1078 // glibc dynamic linker supports, so it seems appropriate to issue an
1079 // error even if the section is not read-only.
1082 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
1086 // These are the relocation types supported by glibc for x86_64.
1087 case elfcpp::R_X86_64_RELATIVE:
1088 case elfcpp::R_X86_64_GLOB_DAT:
1089 case elfcpp::R_X86_64_JUMP_SLOT:
1090 case elfcpp::R_X86_64_DTPMOD64:
1091 case elfcpp::R_X86_64_DTPOFF64:
1092 case elfcpp::R_X86_64_TPOFF64:
1093 case elfcpp::R_X86_64_64:
1094 case elfcpp::R_X86_64_32:
1095 case elfcpp::R_X86_64_PC32:
1096 case elfcpp::R_X86_64_COPY:
1100 // This prevents us from issuing more than one error per reloc
1101 // section. But we can still wind up issuing more than one
1102 // error per object file.
1103 if (this->issued_non_pic_error_)
1105 gold_assert(parameters->options().output_is_position_independent());
1106 object->error(_("requires unsupported dynamic reloc; "
1107 "recompile with -fPIC"));
1108 this->issued_non_pic_error_ = true;
1111 case elfcpp::R_X86_64_NONE:
1116 // Scan a relocation for a local symbol.
1119 Target_x86_64::Scan::local(Symbol_table* symtab,
1121 Target_x86_64* target,
1122 Sized_relobj<64, false>* object,
1123 unsigned int data_shndx,
1124 Output_section* output_section,
1125 const elfcpp::Rela<64, false>& reloc,
1126 unsigned int r_type,
1127 const elfcpp::Sym<64, false>& lsym)
1131 case elfcpp::R_X86_64_NONE:
1132 case elfcpp::R_386_GNU_VTINHERIT:
1133 case elfcpp::R_386_GNU_VTENTRY:
1136 case elfcpp::R_X86_64_64:
1137 // If building a shared library (or a position-independent
1138 // executable), we need to create a dynamic relocation for this
1139 // location. The relocation applied at link time will apply the
1140 // link-time value, so we flag the location with an
1141 // R_X86_64_RELATIVE relocation so the dynamic loader can
1142 // relocate it easily.
1143 if (parameters->options().output_is_position_independent())
1145 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1146 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1147 rela_dyn->add_local_relative(object, r_sym,
1148 elfcpp::R_X86_64_RELATIVE,
1149 output_section, data_shndx,
1150 reloc.get_r_offset(),
1151 reloc.get_r_addend());
1155 case elfcpp::R_X86_64_32:
1156 case elfcpp::R_X86_64_32S:
1157 case elfcpp::R_X86_64_16:
1158 case elfcpp::R_X86_64_8:
1159 // If building a shared library (or a position-independent
1160 // executable), we need to create a dynamic relocation for this
1161 // location. We can't use an R_X86_64_RELATIVE relocation
1162 // because that is always a 64-bit relocation.
1163 if (parameters->options().output_is_position_independent())
1165 this->check_non_pic(object, r_type);
1167 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1168 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1169 if (lsym.get_st_type() != elfcpp::STT_SECTION)
1170 rela_dyn->add_local(object, r_sym, r_type, output_section,
1171 data_shndx, reloc.get_r_offset(),
1172 reloc.get_r_addend());
1175 gold_assert(lsym.get_st_value() == 0);
1176 unsigned int shndx = lsym.get_st_shndx();
1178 shndx = object->adjust_sym_shndx(r_sym, shndx,
1181 object->error(_("section symbol %u has bad shndx %u"),
1184 rela_dyn->add_local_section(object, shndx,
1185 r_type, output_section,
1186 data_shndx, reloc.get_r_offset(),
1187 reloc.get_r_addend());
1192 case elfcpp::R_X86_64_PC64:
1193 case elfcpp::R_X86_64_PC32:
1194 case elfcpp::R_X86_64_PC16:
1195 case elfcpp::R_X86_64_PC8:
1198 case elfcpp::R_X86_64_PLT32:
1199 // Since we know this is a local symbol, we can handle this as a
1203 case elfcpp::R_X86_64_GOTPC32:
1204 case elfcpp::R_X86_64_GOTOFF64:
1205 case elfcpp::R_X86_64_GOTPC64:
1206 case elfcpp::R_X86_64_PLTOFF64:
1207 // We need a GOT section.
1208 target->got_section(symtab, layout);
1209 // For PLTOFF64, we'd normally want a PLT section, but since we
1210 // know this is a local symbol, no PLT is needed.
1213 case elfcpp::R_X86_64_GOT64:
1214 case elfcpp::R_X86_64_GOT32:
1215 case elfcpp::R_X86_64_GOTPCREL64:
1216 case elfcpp::R_X86_64_GOTPCREL:
1217 case elfcpp::R_X86_64_GOTPLT64:
1219 // The symbol requires a GOT entry.
1220 Output_data_got<64, false>* got = target->got_section(symtab, layout);
1221 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1222 if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1224 // If we are generating a shared object, we need to add a
1225 // dynamic relocation for this symbol's GOT entry.
1226 if (parameters->options().output_is_position_independent())
1228 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1229 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1230 if (r_type != elfcpp::R_X86_64_GOT32)
1231 rela_dyn->add_local_relative(
1232 object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
1233 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1236 this->check_non_pic(object, r_type);
1238 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1239 rela_dyn->add_local(
1240 object, r_sym, r_type, got,
1241 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1245 // For GOTPLT64, we'd normally want a PLT section, but since
1246 // we know this is a local symbol, no PLT is needed.
1250 case elfcpp::R_X86_64_COPY:
1251 case elfcpp::R_X86_64_GLOB_DAT:
1252 case elfcpp::R_X86_64_JUMP_SLOT:
1253 case elfcpp::R_X86_64_RELATIVE:
1254 // These are outstanding tls relocs, which are unexpected when linking
1255 case elfcpp::R_X86_64_TPOFF64:
1256 case elfcpp::R_X86_64_DTPMOD64:
1257 case elfcpp::R_X86_64_TLSDESC:
1258 gold_error(_("%s: unexpected reloc %u in object file"),
1259 object->name().c_str(), r_type);
1262 // These are initial tls relocs, which are expected when linking
1263 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
1264 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
1265 case elfcpp::R_X86_64_TLSDESC_CALL:
1266 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
1267 case elfcpp::R_X86_64_DTPOFF32:
1268 case elfcpp::R_X86_64_DTPOFF64:
1269 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
1270 case elfcpp::R_X86_64_TPOFF32: // Local-exec
1272 bool output_is_shared = parameters->options().shared();
1273 const tls::Tls_optimization optimized_type
1274 = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1277 case elfcpp::R_X86_64_TLSGD: // General-dynamic
1278 if (optimized_type == tls::TLSOPT_NONE)
1280 // Create a pair of GOT entries for the module index and
1281 // dtv-relative offset.
1282 Output_data_got<64, false>* got
1283 = target->got_section(symtab, layout);
1284 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1285 unsigned int shndx = lsym.get_st_shndx();
1287 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1289 object->error(_("local symbol %u has bad shndx %u"),
1292 got->add_local_pair_with_rela(object, r_sym,
1295 target->rela_dyn_section(layout),
1296 elfcpp::R_X86_64_DTPMOD64, 0);
1298 else if (optimized_type != tls::TLSOPT_TO_LE)
1299 unsupported_reloc_local(object, r_type);
1302 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1303 target->define_tls_base_symbol(symtab, layout);
1304 if (optimized_type == tls::TLSOPT_NONE)
1306 // Create reserved PLT and GOT entries for the resolver.
1307 target->reserve_tlsdesc_entries(symtab, layout);
1309 // Generate a double GOT entry with an R_X86_64_TLSDESC reloc.
1310 Output_data_got<64, false>* got
1311 = target->got_section(symtab, layout);
1312 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1313 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1315 unsigned int got_offset = got->add_constant(0);
1316 got->add_constant(0);
1317 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1319 Reloc_section* rt = target->rela_tlsdesc_section(layout);
1320 // We store the arguments we need in a vector, and
1321 // use the index into the vector as the parameter
1322 // to pass to the target specific routines.
1323 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
1324 void* arg = reinterpret_cast<void*>(intarg);
1325 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1326 got, got_offset, 0);
1329 else if (optimized_type != tls::TLSOPT_TO_LE)
1330 unsupported_reloc_local(object, r_type);
1333 case elfcpp::R_X86_64_TLSDESC_CALL:
1336 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
1337 if (optimized_type == tls::TLSOPT_NONE)
1339 // Create a GOT entry for the module index.
1340 target->got_mod_index_entry(symtab, layout, object);
1342 else if (optimized_type != tls::TLSOPT_TO_LE)
1343 unsupported_reloc_local(object, r_type);
1346 case elfcpp::R_X86_64_DTPOFF32:
1347 case elfcpp::R_X86_64_DTPOFF64:
1350 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
1351 layout->set_has_static_tls();
1352 if (optimized_type == tls::TLSOPT_NONE)
1354 // Create a GOT entry for the tp-relative offset.
1355 Output_data_got<64, false>* got
1356 = target->got_section(symtab, layout);
1357 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1358 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1359 target->rela_dyn_section(layout),
1360 elfcpp::R_X86_64_TPOFF64);
1362 else if (optimized_type != tls::TLSOPT_TO_LE)
1363 unsupported_reloc_local(object, r_type);
1366 case elfcpp::R_X86_64_TPOFF32: // Local-exec
1367 layout->set_has_static_tls();
1368 if (output_is_shared)
1369 unsupported_reloc_local(object, r_type);
1378 case elfcpp::R_X86_64_SIZE32:
1379 case elfcpp::R_X86_64_SIZE64:
1381 gold_error(_("%s: unsupported reloc %u against local symbol"),
1382 object->name().c_str(), r_type);
1388 // Report an unsupported relocation against a global symbol.
1391 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1392 unsigned int r_type,
1395 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1396 object->name().c_str(), r_type, gsym->demangled_name().c_str());
1399 // Returns true if this relocation type could be that of a function pointer.
1401 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
1405 case elfcpp::R_X86_64_64:
1406 case elfcpp::R_X86_64_32:
1407 case elfcpp::R_X86_64_32S:
1408 case elfcpp::R_X86_64_16:
1409 case elfcpp::R_X86_64_8:
1410 case elfcpp::R_X86_64_GOT64:
1411 case elfcpp::R_X86_64_GOT32:
1412 case elfcpp::R_X86_64_GOTPCREL64:
1413 case elfcpp::R_X86_64_GOTPCREL:
1414 case elfcpp::R_X86_64_GOTPLT64:
1422 // For safe ICF, scan a relocation for a local symbol to check if it
1423 // corresponds to a function pointer being taken. In that case mark
1424 // the function whose pointer was taken as not foldable.
1427 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1431 Sized_relobj<64, false>* ,
1434 const elfcpp::Rela<64, false>& ,
1435 unsigned int r_type,
1436 const elfcpp::Sym<64, false>&)
1438 // When building a shared library, do not fold any local symbols as it is
1439 // not possible to distinguish pointer taken versus a call by looking at
1440 // the relocation types.
1441 return (parameters->options().shared()
1442 || possible_function_pointer_reloc(r_type));
1445 // For safe ICF, scan a relocation for a global symbol to check if it
1446 // corresponds to a function pointer being taken. In that case mark
1447 // the function whose pointer was taken as not foldable.
1450 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1454 Sized_relobj<64, false>* ,
1457 const elfcpp::Rela<64, false>& ,
1458 unsigned int r_type,
1461 // When building a shared library, do not fold symbols whose visibility
1462 // is hidden, internal or protected.
1463 return ((parameters->options().shared()
1464 && (gsym->visibility() == elfcpp::STV_INTERNAL
1465 || gsym->visibility() == elfcpp::STV_PROTECTED
1466 || gsym->visibility() == elfcpp::STV_HIDDEN))
1467 || possible_function_pointer_reloc(r_type));
1470 // Scan a relocation for a global symbol.
1473 Target_x86_64::Scan::global(Symbol_table* symtab,
1475 Target_x86_64* target,
1476 Sized_relobj<64, false>* object,
1477 unsigned int data_shndx,
1478 Output_section* output_section,
1479 const elfcpp::Rela<64, false>& reloc,
1480 unsigned int r_type,
1485 case elfcpp::R_X86_64_NONE:
1486 case elfcpp::R_386_GNU_VTINHERIT:
1487 case elfcpp::R_386_GNU_VTENTRY:
1490 case elfcpp::R_X86_64_64:
1491 case elfcpp::R_X86_64_32:
1492 case elfcpp::R_X86_64_32S:
1493 case elfcpp::R_X86_64_16:
1494 case elfcpp::R_X86_64_8:
1496 // Make a PLT entry if necessary.
1497 if (gsym->needs_plt_entry())
1499 target->make_plt_entry(symtab, layout, gsym);
1500 // Since this is not a PC-relative relocation, we may be
1501 // taking the address of a function. In that case we need to
1502 // set the entry in the dynamic symbol table to the address of
1504 if (gsym->is_from_dynobj() && !parameters->options().shared())
1505 gsym->set_needs_dynsym_value();
1507 // Make a dynamic relocation if necessary.
1508 if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1510 if (gsym->may_need_copy_reloc())
1512 target->copy_reloc(symtab, layout, object,
1513 data_shndx, output_section, gsym, reloc);
1515 else if (r_type == elfcpp::R_X86_64_64
1516 && gsym->can_use_relative_reloc(false))
1518 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1519 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1520 output_section, object,
1521 data_shndx, reloc.get_r_offset(),
1522 reloc.get_r_addend());
1526 this->check_non_pic(object, r_type);
1527 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1528 rela_dyn->add_global(gsym, r_type, output_section, object,
1529 data_shndx, reloc.get_r_offset(),
1530 reloc.get_r_addend());
1536 case elfcpp::R_X86_64_PC64:
1537 case elfcpp::R_X86_64_PC32:
1538 case elfcpp::R_X86_64_PC16:
1539 case elfcpp::R_X86_64_PC8:
1541 // Make a PLT entry if necessary.
1542 if (gsym->needs_plt_entry())
1543 target->make_plt_entry(symtab, layout, gsym);
1544 // Make a dynamic relocation if necessary.
1545 int flags = Symbol::NON_PIC_REF;
1546 if (gsym->is_func())
1547 flags |= Symbol::FUNCTION_CALL;
1548 if (gsym->needs_dynamic_reloc(flags))
1550 if (gsym->may_need_copy_reloc())
1552 target->copy_reloc(symtab, layout, object,
1553 data_shndx, output_section, gsym, reloc);
1557 this->check_non_pic(object, r_type);
1558 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1559 rela_dyn->add_global(gsym, r_type, output_section, object,
1560 data_shndx, reloc.get_r_offset(),
1561 reloc.get_r_addend());
1567 case elfcpp::R_X86_64_GOT64:
1568 case elfcpp::R_X86_64_GOT32:
1569 case elfcpp::R_X86_64_GOTPCREL64:
1570 case elfcpp::R_X86_64_GOTPCREL:
1571 case elfcpp::R_X86_64_GOTPLT64:
1573 // The symbol requires a GOT entry.
1574 Output_data_got<64, false>* got = target->got_section(symtab, layout);
1575 if (gsym->final_value_is_known())
1576 got->add_global(gsym, GOT_TYPE_STANDARD);
1579 // If this symbol is not fully resolved, we need to add a
1580 // dynamic relocation for it.
1581 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1582 if (gsym->is_from_dynobj()
1583 || gsym->is_undefined()
1584 || gsym->is_preemptible())
1585 got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1586 elfcpp::R_X86_64_GLOB_DAT);
1589 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1590 rela_dyn->add_global_relative(
1591 gsym, elfcpp::R_X86_64_RELATIVE, got,
1592 gsym->got_offset(GOT_TYPE_STANDARD), 0);
1595 // For GOTPLT64, we also need a PLT entry (but only if the
1596 // symbol is not fully resolved).
1597 if (r_type == elfcpp::R_X86_64_GOTPLT64
1598 && !gsym->final_value_is_known())
1599 target->make_plt_entry(symtab, layout, gsym);
1603 case elfcpp::R_X86_64_PLT32:
1604 // If the symbol is fully resolved, this is just a PC32 reloc.
1605 // Otherwise we need a PLT entry.
1606 if (gsym->final_value_is_known())
1608 // If building a shared library, we can also skip the PLT entry
1609 // if the symbol is defined in the output file and is protected
1611 if (gsym->is_defined()
1612 && !gsym->is_from_dynobj()
1613 && !gsym->is_preemptible())
1615 target->make_plt_entry(symtab, layout, gsym);
1618 case elfcpp::R_X86_64_GOTPC32:
1619 case elfcpp::R_X86_64_GOTOFF64:
1620 case elfcpp::R_X86_64_GOTPC64:
1621 case elfcpp::R_X86_64_PLTOFF64:
1622 // We need a GOT section.
1623 target->got_section(symtab, layout);
1624 // For PLTOFF64, we also need a PLT entry (but only if the
1625 // symbol is not fully resolved).
1626 if (r_type == elfcpp::R_X86_64_PLTOFF64
1627 && !gsym->final_value_is_known())
1628 target->make_plt_entry(symtab, layout, gsym);
1631 case elfcpp::R_X86_64_COPY:
1632 case elfcpp::R_X86_64_GLOB_DAT:
1633 case elfcpp::R_X86_64_JUMP_SLOT:
1634 case elfcpp::R_X86_64_RELATIVE:
1635 // These are outstanding tls relocs, which are unexpected when linking
1636 case elfcpp::R_X86_64_TPOFF64:
1637 case elfcpp::R_X86_64_DTPMOD64:
1638 case elfcpp::R_X86_64_TLSDESC:
1639 gold_error(_("%s: unexpected reloc %u in object file"),
1640 object->name().c_str(), r_type);
1643 // These are initial tls relocs, which are expected for global()
1644 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
1645 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
1646 case elfcpp::R_X86_64_TLSDESC_CALL:
1647 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
1648 case elfcpp::R_X86_64_DTPOFF32:
1649 case elfcpp::R_X86_64_DTPOFF64:
1650 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
1651 case elfcpp::R_X86_64_TPOFF32: // Local-exec
1653 const bool is_final = gsym->final_value_is_known();
1654 const tls::Tls_optimization optimized_type
1655 = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1658 case elfcpp::R_X86_64_TLSGD: // General-dynamic
1659 if (optimized_type == tls::TLSOPT_NONE)
1661 // Create a pair of GOT entries for the module index and
1662 // dtv-relative offset.
1663 Output_data_got<64, false>* got
1664 = target->got_section(symtab, layout);
1665 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1666 target->rela_dyn_section(layout),
1667 elfcpp::R_X86_64_DTPMOD64,
1668 elfcpp::R_X86_64_DTPOFF64);
1670 else if (optimized_type == tls::TLSOPT_TO_IE)
1672 // Create a GOT entry for the tp-relative offset.
1673 Output_data_got<64, false>* got
1674 = target->got_section(symtab, layout);
1675 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1676 target->rela_dyn_section(layout),
1677 elfcpp::R_X86_64_TPOFF64);
1679 else if (optimized_type != tls::TLSOPT_TO_LE)
1680 unsupported_reloc_global(object, r_type, gsym);
1683 case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1684 target->define_tls_base_symbol(symtab, layout);
1685 if (optimized_type == tls::TLSOPT_NONE)
1687 // Create reserved PLT and GOT entries for the resolver.
1688 target->reserve_tlsdesc_entries(symtab, layout);
1690 // Create a double GOT entry with an R_X86_64_TLSDESC reloc.
1691 Output_data_got<64, false>* got
1692 = target->got_section(symtab, layout);
1693 Reloc_section *rt = target->rela_tlsdesc_section(layout);
1694 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
1695 elfcpp::R_X86_64_TLSDESC, 0);
1697 else if (optimized_type == tls::TLSOPT_TO_IE)
1699 // Create a GOT entry for the tp-relative offset.
1700 Output_data_got<64, false>* got
1701 = target->got_section(symtab, layout);
1702 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1703 target->rela_dyn_section(layout),
1704 elfcpp::R_X86_64_TPOFF64);
1706 else if (optimized_type != tls::TLSOPT_TO_LE)
1707 unsupported_reloc_global(object, r_type, gsym);
1710 case elfcpp::R_X86_64_TLSDESC_CALL:
1713 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
1714 if (optimized_type == tls::TLSOPT_NONE)
1716 // Create a GOT entry for the module index.
1717 target->got_mod_index_entry(symtab, layout, object);
1719 else if (optimized_type != tls::TLSOPT_TO_LE)
1720 unsupported_reloc_global(object, r_type, gsym);
1723 case elfcpp::R_X86_64_DTPOFF32:
1724 case elfcpp::R_X86_64_DTPOFF64:
1727 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
1728 layout->set_has_static_tls();
1729 if (optimized_type == tls::TLSOPT_NONE)
1731 // Create a GOT entry for the tp-relative offset.
1732 Output_data_got<64, false>* got
1733 = target->got_section(symtab, layout);
1734 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1735 target->rela_dyn_section(layout),
1736 elfcpp::R_X86_64_TPOFF64);
1738 else if (optimized_type != tls::TLSOPT_TO_LE)
1739 unsupported_reloc_global(object, r_type, gsym);
1742 case elfcpp::R_X86_64_TPOFF32: // Local-exec
1743 layout->set_has_static_tls();
1744 if (parameters->options().shared())
1745 unsupported_reloc_local(object, r_type);
1754 case elfcpp::R_X86_64_SIZE32:
1755 case elfcpp::R_X86_64_SIZE64:
1757 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1758 object->name().c_str(), r_type,
1759 gsym->demangled_name().c_str());
1765 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
1767 Sized_relobj<64, false>* object,
1768 unsigned int data_shndx,
1769 unsigned int sh_type,
1770 const unsigned char* prelocs,
1772 Output_section* output_section,
1773 bool needs_special_offset_handling,
1774 size_t local_symbol_count,
1775 const unsigned char* plocal_symbols)
1778 if (sh_type == elfcpp::SHT_REL)
1783 gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1784 Target_x86_64::Scan>(
1793 needs_special_offset_handling,
1798 // Scan relocations for a section.
1801 Target_x86_64::scan_relocs(Symbol_table* symtab,
1803 Sized_relobj<64, false>* object,
1804 unsigned int data_shndx,
1805 unsigned int sh_type,
1806 const unsigned char* prelocs,
1808 Output_section* output_section,
1809 bool needs_special_offset_handling,
1810 size_t local_symbol_count,
1811 const unsigned char* plocal_symbols)
1813 if (sh_type == elfcpp::SHT_REL)
1815 gold_error(_("%s: unsupported REL reloc section"),
1816 object->name().c_str());
1820 gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1821 Target_x86_64::Scan>(
1830 needs_special_offset_handling,
1835 // Finalize the sections.
1838 Target_x86_64::do_finalize_sections(
1840 const Input_objects*,
1841 Symbol_table* symtab)
1843 const Reloc_section* rel_plt = (this->plt_ == NULL
1845 : this->plt_->rela_plt());
1846 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
1847 this->rela_dyn_, true, false);
1849 // Fill in some more dynamic tags.
1850 Output_data_dynamic* const odyn = layout->dynamic_data();
1853 if (this->plt_ != NULL
1854 && this->plt_->output_section() != NULL
1855 && this->plt_->has_tlsdesc_entry())
1857 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
1858 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
1859 this->got_->finalize_data_size();
1860 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
1861 this->plt_, plt_offset);
1862 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
1863 this->got_, got_offset);
1867 // Emit any relocs we saved in an attempt to avoid generating COPY
1869 if (this->copy_relocs_.any_saved_relocs())
1870 this->copy_relocs_.emit(this->rela_dyn_section(layout));
1872 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1873 // the .got.plt section.
1874 Symbol* sym = this->global_offset_table_;
1877 uint64_t data_size = this->got_plt_->current_data_size();
1878 symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
1882 // Perform a relocation.
1885 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1886 Target_x86_64* target,
1889 const elfcpp::Rela<64, false>& rela,
1890 unsigned int r_type,
1891 const Sized_symbol<64>* gsym,
1892 const Symbol_value<64>* psymval,
1893 unsigned char* view,
1894 elfcpp::Elf_types<64>::Elf_Addr address,
1895 section_size_type view_size)
1897 if (this->skip_call_tls_get_addr_)
1899 if ((r_type != elfcpp::R_X86_64_PLT32
1900 && r_type != elfcpp::R_X86_64_PC32)
1902 || strcmp(gsym->name(), "__tls_get_addr") != 0)
1904 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1905 _("missing expected TLS relocation"));
1909 this->skip_call_tls_get_addr_ = false;
1914 // Pick the value to use for symbols defined in shared objects.
1915 Symbol_value<64> symval;
1917 && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
1918 || r_type == elfcpp::R_X86_64_PC32
1919 || r_type == elfcpp::R_X86_64_PC16
1920 || r_type == elfcpp::R_X86_64_PC8))
1922 symval.set_output_value(target->plt_section()->address()
1923 + gsym->plt_offset());
1927 const Sized_relobj<64, false>* object = relinfo->object;
1928 const elfcpp::Elf_Xword addend = rela.get_r_addend();
1930 // Get the GOT offset if needed.
1931 // The GOT pointer points to the end of the GOT section.
1932 // We need to subtract the size of the GOT section to get
1933 // the actual offset to use in the relocation.
1934 bool have_got_offset = false;
1935 unsigned int got_offset = 0;
1938 case elfcpp::R_X86_64_GOT32:
1939 case elfcpp::R_X86_64_GOT64:
1940 case elfcpp::R_X86_64_GOTPLT64:
1941 case elfcpp::R_X86_64_GOTPCREL:
1942 case elfcpp::R_X86_64_GOTPCREL64:
1945 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1946 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1950 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1951 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1952 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1953 - target->got_size());
1955 have_got_offset = true;
1964 case elfcpp::R_X86_64_NONE:
1965 case elfcpp::R_386_GNU_VTINHERIT:
1966 case elfcpp::R_386_GNU_VTENTRY:
1969 case elfcpp::R_X86_64_64:
1970 Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1973 case elfcpp::R_X86_64_PC64:
1974 Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1978 case elfcpp::R_X86_64_32:
1979 // FIXME: we need to verify that value + addend fits into 32 bits:
1980 // uint64_t x = value + addend;
1981 // x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1982 // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1983 Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1986 case elfcpp::R_X86_64_32S:
1987 // FIXME: we need to verify that value + addend fits into 32 bits:
1988 // int64_t x = value + addend; // note this quantity is signed!
1989 // x == static_cast<int64_t>(static_cast<int32_t>(x))
1990 Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1993 case elfcpp::R_X86_64_PC32:
1994 Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1998 case elfcpp::R_X86_64_16:
1999 Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2002 case elfcpp::R_X86_64_PC16:
2003 Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2007 case elfcpp::R_X86_64_8:
2008 Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2011 case elfcpp::R_X86_64_PC8:
2012 Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2016 case elfcpp::R_X86_64_PLT32:
2017 gold_assert(gsym == NULL
2018 || gsym->has_plt_offset()
2019 || gsym->final_value_is_known()
2020 || (gsym->is_defined()
2021 && !gsym->is_from_dynobj()
2022 && !gsym->is_preemptible()));
2023 // Note: while this code looks the same as for R_X86_64_PC32, it
2024 // behaves differently because psymval was set to point to
2025 // the PLT entry, rather than the symbol, in Scan::global().
2026 Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2030 case elfcpp::R_X86_64_PLTOFF64:
2033 gold_assert(gsym->has_plt_offset()
2034 || gsym->final_value_is_known());
2035 elfcpp::Elf_types<64>::Elf_Addr got_address;
2036 got_address = target->got_section(NULL, NULL)->address();
2037 Relocate_functions<64, false>::rela64(view, object, psymval,
2038 addend - got_address);
2041 case elfcpp::R_X86_64_GOT32:
2042 gold_assert(have_got_offset);
2043 Relocate_functions<64, false>::rela32(view, got_offset, addend);
2046 case elfcpp::R_X86_64_GOTPC32:
2049 elfcpp::Elf_types<64>::Elf_Addr value;
2050 value = target->got_plt_section()->address();
2051 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2055 case elfcpp::R_X86_64_GOT64:
2056 // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2057 // Since we always add a PLT entry, this is equivalent.
2058 case elfcpp::R_X86_64_GOTPLT64:
2059 gold_assert(have_got_offset);
2060 Relocate_functions<64, false>::rela64(view, got_offset, addend);
2063 case elfcpp::R_X86_64_GOTPC64:
2066 elfcpp::Elf_types<64>::Elf_Addr value;
2067 value = target->got_plt_section()->address();
2068 Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2072 case elfcpp::R_X86_64_GOTOFF64:
2074 elfcpp::Elf_types<64>::Elf_Addr value;
2075 value = (psymval->value(object, 0)
2076 - target->got_plt_section()->address());
2077 Relocate_functions<64, false>::rela64(view, value, addend);
2081 case elfcpp::R_X86_64_GOTPCREL:
2083 gold_assert(have_got_offset);
2084 elfcpp::Elf_types<64>::Elf_Addr value;
2085 value = target->got_plt_section()->address() + got_offset;
2086 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2090 case elfcpp::R_X86_64_GOTPCREL64:
2092 gold_assert(have_got_offset);
2093 elfcpp::Elf_types<64>::Elf_Addr value;
2094 value = target->got_plt_section()->address() + got_offset;
2095 Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2099 case elfcpp::R_X86_64_COPY:
2100 case elfcpp::R_X86_64_GLOB_DAT:
2101 case elfcpp::R_X86_64_JUMP_SLOT:
2102 case elfcpp::R_X86_64_RELATIVE:
2103 // These are outstanding tls relocs, which are unexpected when linking
2104 case elfcpp::R_X86_64_TPOFF64:
2105 case elfcpp::R_X86_64_DTPMOD64:
2106 case elfcpp::R_X86_64_TLSDESC:
2107 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2108 _("unexpected reloc %u in object file"),
2112 // These are initial tls relocs, which are expected when linking
2113 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2114 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2115 case elfcpp::R_X86_64_TLSDESC_CALL:
2116 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2117 case elfcpp::R_X86_64_DTPOFF32:
2118 case elfcpp::R_X86_64_DTPOFF64:
2119 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2120 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2121 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
2122 view, address, view_size);
2125 case elfcpp::R_X86_64_SIZE32:
2126 case elfcpp::R_X86_64_SIZE64:
2128 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2129 _("unsupported reloc %u"),
2137 // Perform a TLS relocation.
2140 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
2141 Target_x86_64* target,
2143 const elfcpp::Rela<64, false>& rela,
2144 unsigned int r_type,
2145 const Sized_symbol<64>* gsym,
2146 const Symbol_value<64>* psymval,
2147 unsigned char* view,
2148 elfcpp::Elf_types<64>::Elf_Addr address,
2149 section_size_type view_size)
2151 Output_segment* tls_segment = relinfo->layout->tls_segment();
2153 const Sized_relobj<64, false>* object = relinfo->object;
2154 const elfcpp::Elf_Xword addend = rela.get_r_addend();
2156 elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
2158 const bool is_final = (gsym == NULL
2159 ? !parameters->options().shared()
2160 : gsym->final_value_is_known());
2161 const tls::Tls_optimization optimized_type
2162 = Target_x86_64::optimize_tls_reloc(is_final, r_type);
2165 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2166 this->saw_tls_block_reloc_ = true;
2167 if (optimized_type == tls::TLSOPT_TO_LE)
2169 gold_assert(tls_segment != NULL);
2170 this->tls_gd_to_le(relinfo, relnum, tls_segment,
2171 rela, r_type, value, view,
2177 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2178 ? GOT_TYPE_TLS_OFFSET
2179 : GOT_TYPE_TLS_PAIR);
2180 unsigned int got_offset;
2183 gold_assert(gsym->has_got_offset(got_type));
2184 got_offset = gsym->got_offset(got_type) - target->got_size();
2188 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2189 gold_assert(object->local_has_got_offset(r_sym, got_type));
2190 got_offset = (object->local_got_offset(r_sym, got_type)
2191 - target->got_size());
2193 if (optimized_type == tls::TLSOPT_TO_IE)
2195 gold_assert(tls_segment != NULL);
2196 value = target->got_plt_section()->address() + got_offset;
2197 this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2198 value, view, address, view_size);
2201 else if (optimized_type == tls::TLSOPT_NONE)
2203 // Relocate the field with the offset of the pair of GOT
2205 value = target->got_plt_section()->address() + got_offset;
2206 Relocate_functions<64, false>::pcrela32(view, value, addend,
2211 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2212 _("unsupported reloc %u"), r_type);
2215 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2216 case elfcpp::R_X86_64_TLSDESC_CALL:
2217 this->saw_tls_block_reloc_ = true;
2218 if (optimized_type == tls::TLSOPT_TO_LE)
2220 gold_assert(tls_segment != NULL);
2221 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2222 rela, r_type, value, view,
2228 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2229 ? GOT_TYPE_TLS_OFFSET
2230 : GOT_TYPE_TLS_DESC);
2231 unsigned int got_offset;
2234 gold_assert(gsym->has_got_offset(got_type));
2235 got_offset = gsym->got_offset(got_type) - target->got_size();
2239 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2240 gold_assert(object->local_has_got_offset(r_sym, got_type));
2241 got_offset = (object->local_got_offset(r_sym, got_type)
2242 - target->got_size());
2244 if (optimized_type == tls::TLSOPT_TO_IE)
2246 gold_assert(tls_segment != NULL);
2247 value = target->got_plt_section()->address() + got_offset;
2248 this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2249 rela, r_type, value, view, address,
2253 else if (optimized_type == tls::TLSOPT_NONE)
2255 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2257 // Relocate the field with the offset of the pair of GOT
2259 value = target->got_plt_section()->address() + got_offset;
2260 Relocate_functions<64, false>::pcrela32(view, value, addend,
2266 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2267 _("unsupported reloc %u"), r_type);
2270 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2271 this->saw_tls_block_reloc_ = true;
2272 if (optimized_type == tls::TLSOPT_TO_LE)
2274 gold_assert(tls_segment != NULL);
2275 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2276 value, view, view_size);
2279 else if (optimized_type == tls::TLSOPT_NONE)
2281 // Relocate the field with the offset of the GOT entry for
2282 // the module index.
2283 unsigned int got_offset;
2284 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2285 - target->got_size());
2286 value = target->got_plt_section()->address() + got_offset;
2287 Relocate_functions<64, false>::pcrela32(view, value, addend,
2291 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2292 _("unsupported reloc %u"), r_type);
2295 case elfcpp::R_X86_64_DTPOFF32:
2296 if (optimized_type == tls::TLSOPT_TO_LE)
2298 // This relocation type is used in debugging information.
2299 // In that case we need to not optimize the value. If we
2300 // haven't seen a TLSLD reloc, then we assume we should not
2301 // optimize this reloc.
2302 if (this->saw_tls_block_reloc_)
2304 gold_assert(tls_segment != NULL);
2305 value -= tls_segment->memsz();
2308 Relocate_functions<64, false>::rela32(view, value, addend);
2311 case elfcpp::R_X86_64_DTPOFF64:
2312 if (optimized_type == tls::TLSOPT_TO_LE)
2314 // See R_X86_64_DTPOFF32, just above, for why we test this.
2315 if (this->saw_tls_block_reloc_)
2317 gold_assert(tls_segment != NULL);
2318 value -= tls_segment->memsz();
2321 Relocate_functions<64, false>::rela64(view, value, addend);
2324 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2325 if (optimized_type == tls::TLSOPT_TO_LE)
2327 gold_assert(tls_segment != NULL);
2328 Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2329 rela, r_type, value, view,
2333 else if (optimized_type == tls::TLSOPT_NONE)
2335 // Relocate the field with the offset of the GOT entry for
2336 // the tp-relative offset of the symbol.
2337 unsigned int got_offset;
2340 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2341 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2342 - target->got_size());
2346 unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2347 gold_assert(object->local_has_got_offset(r_sym,
2348 GOT_TYPE_TLS_OFFSET));
2349 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2350 - target->got_size());
2352 value = target->got_plt_section()->address() + got_offset;
2353 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2356 gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2357 _("unsupported reloc type %u"),
2361 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2362 value -= tls_segment->memsz();
2363 Relocate_functions<64, false>::rela32(view, value, addend);
2368 // Do a relocation in which we convert a TLS General-Dynamic to an
2372 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2375 const elfcpp::Rela<64, false>& rela,
2377 elfcpp::Elf_types<64>::Elf_Addr value,
2378 unsigned char* view,
2379 elfcpp::Elf_types<64>::Elf_Addr address,
2380 section_size_type view_size)
2382 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2383 // .word 0x6666; rex64; call __tls_get_addr
2384 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2386 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2387 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2389 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2390 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2391 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2392 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2394 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2396 const elfcpp::Elf_Xword addend = rela.get_r_addend();
2397 Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2399 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2401 this->skip_call_tls_get_addr_ = true;
2404 // Do a relocation in which we convert a TLS General-Dynamic to a
2408 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2410 Output_segment* tls_segment,
2411 const elfcpp::Rela<64, false>& rela,
2413 elfcpp::Elf_types<64>::Elf_Addr value,
2414 unsigned char* view,
2415 section_size_type view_size)
2417 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2418 // .word 0x6666; rex64; call __tls_get_addr
2419 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2421 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2422 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2424 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2425 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2426 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2427 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2429 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2431 value -= tls_segment->memsz();
2432 Relocate_functions<64, false>::rela32(view + 8, value, 0);
2434 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2436 this->skip_call_tls_get_addr_ = true;
2439 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2442 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2443 const Relocate_info<64, false>* relinfo,
2446 const elfcpp::Rela<64, false>& rela,
2447 unsigned int r_type,
2448 elfcpp::Elf_types<64>::Elf_Addr value,
2449 unsigned char* view,
2450 elfcpp::Elf_types<64>::Elf_Addr address,
2451 section_size_type view_size)
2453 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2455 // leaq foo@tlsdesc(%rip), %rax
2456 // ==> movq foo@gottpoff(%rip), %rax
2457 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2458 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2459 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2460 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2462 const elfcpp::Elf_Xword addend = rela.get_r_addend();
2463 Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2467 // call *foo@tlscall(%rax)
2469 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2470 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2471 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2472 view[0] == 0xff && view[1] == 0x10);
2478 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2481 Target_x86_64::Relocate::tls_desc_gd_to_le(
2482 const Relocate_info<64, false>* relinfo,
2484 Output_segment* tls_segment,
2485 const elfcpp::Rela<64, false>& rela,
2486 unsigned int r_type,
2487 elfcpp::Elf_types<64>::Elf_Addr value,
2488 unsigned char* view,
2489 section_size_type view_size)
2491 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2493 // leaq foo@tlsdesc(%rip), %rax
2494 // ==> movq foo@tpoff, %rax
2495 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2496 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2497 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2498 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2501 value -= tls_segment->memsz();
2502 Relocate_functions<64, false>::rela32(view, value, 0);
2506 // call *foo@tlscall(%rax)
2508 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2509 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2510 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2511 view[0] == 0xff && view[1] == 0x10);
2518 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2521 const elfcpp::Rela<64, false>& rela,
2523 elfcpp::Elf_types<64>::Elf_Addr,
2524 unsigned char* view,
2525 section_size_type view_size)
2527 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2528 // ... leq foo@dtpoff(%rax),%reg
2529 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2531 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2532 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2534 tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2535 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2537 tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2539 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2541 // The next reloc should be a PLT32 reloc against __tls_get_addr.
2543 this->skip_call_tls_get_addr_ = true;
2546 // Do a relocation in which we convert a TLS Initial-Exec to a
2550 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2552 Output_segment* tls_segment,
2553 const elfcpp::Rela<64, false>& rela,
2555 elfcpp::Elf_types<64>::Elf_Addr value,
2556 unsigned char* view,
2557 section_size_type view_size)
2559 // We need to examine the opcodes to figure out which instruction we
2562 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
2563 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
2565 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2566 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2568 unsigned char op1 = view[-3];
2569 unsigned char op2 = view[-2];
2570 unsigned char op3 = view[-1];
2571 unsigned char reg = op3 >> 3;
2579 view[-1] = 0xc0 | reg;
2583 // Special handling for %rsp.
2587 view[-1] = 0xc0 | reg;
2595 view[-1] = 0x80 | reg | (reg << 3);
2598 value -= tls_segment->memsz();
2599 Relocate_functions<64, false>::rela32(view, value, 0);
2602 // Relocate section data.
2605 Target_x86_64::relocate_section(
2606 const Relocate_info<64, false>* relinfo,
2607 unsigned int sh_type,
2608 const unsigned char* prelocs,
2610 Output_section* output_section,
2611 bool needs_special_offset_handling,
2612 unsigned char* view,
2613 elfcpp::Elf_types<64>::Elf_Addr address,
2614 section_size_type view_size,
2615 const Reloc_symbol_changes* reloc_symbol_changes)
2617 gold_assert(sh_type == elfcpp::SHT_RELA);
2619 gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2620 Target_x86_64::Relocate>(
2626 needs_special_offset_handling,
2630 reloc_symbol_changes);
2633 // Return the size of a relocation while scanning during a relocatable
2637 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2638 unsigned int r_type,
2643 case elfcpp::R_X86_64_NONE:
2644 case elfcpp::R_386_GNU_VTINHERIT:
2645 case elfcpp::R_386_GNU_VTENTRY:
2646 case elfcpp::R_X86_64_TLSGD: // Global-dynamic
2647 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
2648 case elfcpp::R_X86_64_TLSDESC_CALL:
2649 case elfcpp::R_X86_64_TLSLD: // Local-dynamic
2650 case elfcpp::R_X86_64_DTPOFF32:
2651 case elfcpp::R_X86_64_DTPOFF64:
2652 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
2653 case elfcpp::R_X86_64_TPOFF32: // Local-exec
2656 case elfcpp::R_X86_64_64:
2657 case elfcpp::R_X86_64_PC64:
2658 case elfcpp::R_X86_64_GOTOFF64:
2659 case elfcpp::R_X86_64_GOTPC64:
2660 case elfcpp::R_X86_64_PLTOFF64:
2661 case elfcpp::R_X86_64_GOT64:
2662 case elfcpp::R_X86_64_GOTPCREL64:
2663 case elfcpp::R_X86_64_GOTPCREL:
2664 case elfcpp::R_X86_64_GOTPLT64:
2667 case elfcpp::R_X86_64_32:
2668 case elfcpp::R_X86_64_32S:
2669 case elfcpp::R_X86_64_PC32:
2670 case elfcpp::R_X86_64_PLT32:
2671 case elfcpp::R_X86_64_GOTPC32:
2672 case elfcpp::R_X86_64_GOT32:
2675 case elfcpp::R_X86_64_16:
2676 case elfcpp::R_X86_64_PC16:
2679 case elfcpp::R_X86_64_8:
2680 case elfcpp::R_X86_64_PC8:
2683 case elfcpp::R_X86_64_COPY:
2684 case elfcpp::R_X86_64_GLOB_DAT:
2685 case elfcpp::R_X86_64_JUMP_SLOT:
2686 case elfcpp::R_X86_64_RELATIVE:
2687 // These are outstanding tls relocs, which are unexpected when linking
2688 case elfcpp::R_X86_64_TPOFF64:
2689 case elfcpp::R_X86_64_DTPMOD64:
2690 case elfcpp::R_X86_64_TLSDESC:
2691 object->error(_("unexpected reloc %u in object file"), r_type);
2694 case elfcpp::R_X86_64_SIZE32:
2695 case elfcpp::R_X86_64_SIZE64:
2697 object->error(_("unsupported reloc %u against local symbol"), r_type);
2702 // Scan the relocs during a relocatable link.
2705 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
2707 Sized_relobj<64, false>* object,
2708 unsigned int data_shndx,
2709 unsigned int sh_type,
2710 const unsigned char* prelocs,
2712 Output_section* output_section,
2713 bool needs_special_offset_handling,
2714 size_t local_symbol_count,
2715 const unsigned char* plocal_symbols,
2716 Relocatable_relocs* rr)
2718 gold_assert(sh_type == elfcpp::SHT_RELA);
2720 typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2721 Relocatable_size_for_reloc> Scan_relocatable_relocs;
2723 gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2724 Scan_relocatable_relocs>(
2732 needs_special_offset_handling,
2738 // Relocate a section during a relocatable link.
2741 Target_x86_64::relocate_for_relocatable(
2742 const Relocate_info<64, false>* relinfo,
2743 unsigned int sh_type,
2744 const unsigned char* prelocs,
2746 Output_section* output_section,
2747 off_t offset_in_output_section,
2748 const Relocatable_relocs* rr,
2749 unsigned char* view,
2750 elfcpp::Elf_types<64>::Elf_Addr view_address,
2751 section_size_type view_size,
2752 unsigned char* reloc_view,
2753 section_size_type reloc_view_size)
2755 gold_assert(sh_type == elfcpp::SHT_RELA);
2757 gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2762 offset_in_output_section,
2771 // Return the value to use for a dynamic which requires special
2772 // treatment. This is how we support equality comparisons of function
2773 // pointers across shared library boundaries, as described in the
2774 // processor specific ABI supplement.
2777 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2779 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2780 return this->plt_section()->address() + gsym->plt_offset();
2783 // Return a string used to fill a code section with nops to take up
2784 // the specified length.
2787 Target_x86_64::do_code_fill(section_size_type length) const
2791 // Build a jmpq instruction to skip over the bytes.
2792 unsigned char jmp[5];
2794 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2795 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2796 + std::string(length - 5, '\0'));
2799 // Nop sequences of various lengths.
2800 const char nop1[1] = { 0x90 }; // nop
2801 const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
2802 const char nop3[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax)
2803 const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax)
2804 const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1)
2806 const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1)
2808 const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax)
2810 const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1)
2811 0x00, 0x00, 0x00, 0x00 };
2812 const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1)
2813 0x00, 0x00, 0x00, 0x00,
2815 const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
2816 0x84, 0x00, 0x00, 0x00,
2818 const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
2819 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2821 const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
2822 0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
2823 0x00, 0x00, 0x00, 0x00 };
2824 const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2825 0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
2826 0x00, 0x00, 0x00, 0x00,
2828 const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2829 0x66, 0x2e, 0x0f, 0x1f, // data16
2830 0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2832 const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2833 0x66, 0x66, 0x2e, 0x0f, // data16; data16
2834 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2837 const char* nops[16] = {
2839 nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2840 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2843 return std::string(nops[length], length);
2846 // Return the addend to use for a target specific relocation. The
2847 // only target specific relocation is R_X86_64_TLSDESC for a local
2848 // symbol. We want to set the addend is the offset of the local
2849 // symbol in the TLS segment.
2852 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
2855 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
2856 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
2857 gold_assert(intarg < this->tlsdesc_reloc_info_.size());
2858 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
2859 const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
2860 gold_assert(psymval->is_tls_symbol());
2861 // The value of a TLS symbol is the offset in the TLS segment.
2862 return psymval->value(ti.object, 0);
2865 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2866 // compiled with -fstack-split. The function calls non-stack-split
2867 // code. We have to change the function so that it always ensures
2868 // that it has enough stack space to run some random function.
2871 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
2872 section_offset_type fnoffset,
2873 section_size_type fnsize,
2874 unsigned char* view,
2875 section_size_type view_size,
2877 std::string* to) const
2879 // The function starts with a comparison of the stack pointer and a
2880 // field in the TCB. This is followed by a jump.
2883 if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
2886 // We will call __morestack if the carry flag is set after this
2887 // comparison. We turn the comparison into an stc instruction
2889 view[fnoffset] = '\xf9';
2890 this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
2892 // lea NN(%rsp),%r10
2893 // lea NN(%rsp),%r11
2894 else if ((this->match_view(view, view_size, fnoffset,
2895 "\x4c\x8d\x94\x24", 4)
2896 || this->match_view(view, view_size, fnoffset,
2897 "\x4c\x8d\x9c\x24", 4))
2900 // This is loading an offset from the stack pointer for a
2901 // comparison. The offset is negative, so we decrease the
2902 // offset by the amount of space we need for the stack. This
2903 // means we will avoid calling __morestack if there happens to
2904 // be plenty of space on the stack already.
2905 unsigned char* pval = view + fnoffset + 4;
2906 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2907 val -= parameters->options().split_stack_adjust_size();
2908 elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2912 if (!object->has_no_split_stack())
2913 object->error(_("failed to match split-stack sequence at "
2914 "section %u offset %0zx"),
2915 shndx, static_cast<size_t>(fnoffset));
2919 // We have to change the function so that it calls
2920 // __morestack_non_split instead of __morestack. The former will
2921 // allocate additional stack space.
2922 *from = "__morestack";
2923 *to = "__morestack_non_split";
2926 // The selector for x86_64 object files.
2928 class Target_selector_x86_64 : public Target_selector_freebsd
2931 Target_selector_x86_64()
2932 : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
2933 "elf64-x86-64-freebsd")
2937 do_instantiate_target()
2938 { return new Target_x86_64(); }
2942 Target_selector_x86_64 target_selector_x86_64;
2944 } // End anonymous namespace.