contrib/binutils-2.21/gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "parameters.h"
  29 #include "reloc.h"
  30 #include "x86_64.h"
  31 #include "object.h"
  32 #include "symtab.h"
  33 #include "layout.h"
  34 #include "output.h"
  35 #include "copy-relocs.h"
  36 #include "target.h"
  37 #include "target-reloc.h"
  38 #include "target-select.h"
  39 #include "tls.h"
  40 #include "freebsd.h"
  41 #include "gc.h"
  42 #include "icf.h"
  43
  44 namespace
  45 {
  46
  47 using namespace gold;
  48
  49 // A class to handle the PLT data.
  50
  51 class Output_data_plt_x86_64 : public Output_section_data
  52 {
  53  public:
  54   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  55
  56   Output_data_plt_x86_64(Symbol_table*, Layout*, Output_data_got<64, false>*,
  57                          Output_data_space*);
  58
  59   // Add an entry to the PLT.
  60   void
  61   add_entry(Symbol* gsym);
  62
  63   // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
  64   unsigned int
  65   add_local_ifunc_entry(Sized_relobj<64, false>* relobj,
  66                         unsigned int local_sym_index);
  67
  68   // Add the reserved TLSDESC_PLT entry to the PLT.
  69   void
  70   reserve_tlsdesc_entry(unsigned int got_offset)
  71   { this->tlsdesc_got_offset_ = got_offset; }
  72
  73   // Return true if a TLSDESC_PLT entry has been reserved.
  74   bool
  75   has_tlsdesc_entry() const
  76   { return this->tlsdesc_got_offset_ != -1U; }
  77
  78   // Return the GOT offset for the reserved TLSDESC_PLT entry.
  79   unsigned int
  80   get_tlsdesc_got_offset() const
  81   { return this->tlsdesc_got_offset_; }
  82
  83   // Return the offset of the reserved TLSDESC_PLT entry.
  84   unsigned int
  85   get_tlsdesc_plt_offset() const
  86   { return (this->count_ + 1) * plt_entry_size; }
  87
  88   // Return the .rela.plt section data.
  89   Reloc_section*
  90   rela_plt()
  91   { return this->rel_; }
  92
  93   // Return where the TLSDESC relocations should go.
  94   Reloc_section*
  95   rela_tlsdesc(Layout*);
  96
  97   // Return the number of PLT entries.
  98   unsigned int
  99   entry_count() const
 100   { return this->count_; }
 101
 102   // Return the offset of the first non-reserved PLT entry.
 103   static unsigned int
 104   first_plt_entry_offset()
 105   { return plt_entry_size; }
 106
 107   // Return the size of a PLT entry.
 108   static unsigned int
 109   get_plt_entry_size()
 110   { return plt_entry_size; }
 111
 112  protected:
 113   void
 114   do_adjust_output_section(Output_section* os);
 115
 116   // Write to a map file.
 117   void
 118   do_print_to_mapfile(Mapfile* mapfile) const
 119   { mapfile->print_output_data(this, _("** PLT")); }
 120
 121  private:
 122   // The size of an entry in the PLT.
 123   static const int plt_entry_size = 16;
 124
 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];
 129
 130   // Other entries in the PLT for an executable.
 131   static unsigned char plt_entry[plt_entry_size];
 132
 133   // The reserved TLSDESC entry in the PLT for an executable.
 134   static unsigned char tlsdesc_plt_entry[plt_entry_size];
 135
 136   // Set the final size.
 137   void
 138   set_final_data_size();
 139
 140   // Write out the PLT data.
 141   void
 142   do_write(Output_file*);
 143
 144   // The reloc section.
 145   Reloc_section* rel_;
 146   // The TLSDESC relocs, if necessary.  These must follow the regular
 147   // PLT relocs.
 148   Reloc_section* tlsdesc_rel_;
 149   // The .got section.
 150   Output_data_got<64, false>* got_;
 151   // The .got.plt section.
 152   Output_data_space* got_plt_;
 153   // The number of PLT entries.
 154   unsigned int count_;
 155   // Offset of the reserved TLSDESC_GOT entry when needed.
 156   unsigned int tlsdesc_got_offset_;
 157 };
 158
 159 // The x86_64 target class.
 160 // See the ABI at
 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
 165
 166 class Target_x86_64 : public Target_freebsd<64, false>
 167 {
 168  public:
 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;
 172
 173   Target_x86_64()
 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)
 180   { }
 181
 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.
 188   inline bool
 189   can_check_for_function_pointers() const
 190   { return !parameters->options().pie(); }
 191
 192   virtual bool
 193   can_icf_inline_merge_sections () const
 194   { return true; }
 195
 196   // Hook for a new output section.
 197   void
 198   do_new_output_section(Output_section*) const;
 199
 200   // Scan the relocations to look for symbol adjustments.
 201   void
 202   gc_process_relocs(Symbol_table* symtab,
 203                     Layout* layout,
 204                     Sized_relobj<64, false>* object,
 205                     unsigned int data_shndx,
 206                     unsigned int sh_type,
 207                     const unsigned char* prelocs,
 208                     size_t reloc_count,
 209                     Output_section* output_section,
 210                     bool needs_special_offset_handling,
 211                     size_t local_symbol_count,
 212                     const unsigned char* plocal_symbols);
 213
 214   // Scan the relocations to look for symbol adjustments.
 215   void
 216   scan_relocs(Symbol_table* symtab,
 217               Layout* layout,
 218               Sized_relobj<64, false>* object,
 219               unsigned int data_shndx,
 220               unsigned int sh_type,
 221               const unsigned char* prelocs,
 222               size_t reloc_count,
 223               Output_section* output_section,
 224               bool needs_special_offset_handling,
 225               size_t local_symbol_count,
 226               const unsigned char* plocal_symbols);
 227
 228   // Finalize the sections.
 229   void
 230   do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
 231
 232   // Return the value to use for a dynamic which requires special
 233   // treatment.
 234   uint64_t
 235   do_dynsym_value(const Symbol*) const;
 236
 237   // Relocate a section.
 238   void
 239   relocate_section(const Relocate_info<64, false>*,
 240                    unsigned int sh_type,
 241                    const unsigned char* prelocs,
 242                    size_t reloc_count,
 243                    Output_section* output_section,
 244                    bool needs_special_offset_handling,
 245                    unsigned char* view,
 246                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 247                    section_size_type view_size,
 248                    const Reloc_symbol_changes*);
 249
 250   // Scan the relocs during a relocatable link.
 251   void
 252   scan_relocatable_relocs(Symbol_table* symtab,
 253                           Layout* layout,
 254                           Sized_relobj<64, false>* object,
 255                           unsigned int data_shndx,
 256                           unsigned int sh_type,
 257                           const unsigned char* prelocs,
 258                           size_t reloc_count,
 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*);
 264
 265   // Relocate a section during a relocatable link.
 266   void
 267   relocate_for_relocatable(const Relocate_info<64, false>*,
 268                            unsigned int sh_type,
 269                            const unsigned char* prelocs,
 270                            size_t reloc_count,
 271                            Output_section* output_section,
 272                            off_t offset_in_output_section,
 273                            const Relocatable_relocs*,
 274                            unsigned char* view,
 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);
 279
 280   // Return a string used to fill a code section with nops.
 281   std::string
 282   do_code_fill(section_size_type length) const;
 283
 284   // Return whether SYM is defined by the ABI.
 285   bool
 286   do_is_defined_by_abi(const Symbol* sym) const
 287   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 288
 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.
 292   unsigned int
 293   do_reloc_symbol_index(void*, unsigned int r_type) const
 294   {
 295     gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
 296     return 0;
 297   }
 298
 299   // Return the addend to use for a target specific relocation.
 300   uint64_t
 301   do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
 302
 303   // Return the PLT section.
 304   Output_data*
 305   do_plt_section_for_global(const Symbol*) const
 306   { return this->plt_section(); }
 307
 308   Output_data*
 309   do_plt_section_for_local(const Relobj*, unsigned int) const
 310   { return this->plt_section(); }
 311
 312   // Adjust -fstack-split code which calls non-stack-split code.
 313   void
 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;
 318
 319   // Return the size of the GOT section.
 320   section_size_type
 321   got_size() const
 322   {
 323     gold_assert(this->got_ != NULL);
 324     return this->got_->data_size();
 325   }
 326
 327   // Return the number of entries in the GOT.
 328   unsigned int
 329   got_entry_count() const
 330   {
 331     if (this->got_ == NULL)
 332       return 0;
 333     return this->got_size() / 8;
 334   }
 335
 336   // Return the number of entries in the PLT.
 337   unsigned int
 338   plt_entry_count() const;
 339
 340   // Return the offset of the first non-reserved PLT entry.
 341   unsigned int
 342   first_plt_entry_offset() const;
 343
 344   // Return the size of each PLT entry.
 345   unsigned int
 346   plt_entry_size() const;
 347
 348   // Add a new reloc argument, returning the index in the vector.
 349   size_t
 350   add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym)
 351   {
 352     this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
 353     return this->tlsdesc_reloc_info_.size() - 1;
 354   }
 355
 356  private:
 357   // The class which scans relocations.
 358   class Scan
 359   {
 360   public:
 361     Scan()
 362       : issued_non_pic_error_(false)
 363     { }
 364
 365     inline void
 366     local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 367           Sized_relobj<64, false>* object,
 368           unsigned int data_shndx,
 369           Output_section* output_section,
 370           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 371           const elfcpp::Sym<64, false>& lsym);
 372
 373     inline void
 374     global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 375            Sized_relobj<64, false>* object,
 376            unsigned int data_shndx,
 377            Output_section* output_section,
 378            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 379            Symbol* gsym);
 380
 381     inline bool
 382     local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 383                                         Target_x86_64* target,
 384                                         Sized_relobj<64, false>* object,
 385                                         unsigned int data_shndx,
 386                                         Output_section* output_section,
 387                                         const elfcpp::Rela<64, false>& reloc,
 388                                         unsigned int r_type,
 389                                         const elfcpp::Sym<64, false>& lsym);
 390
 391     inline bool
 392     global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 393                                          Target_x86_64* target,
 394                                          Sized_relobj<64, false>* object,
 395                                          unsigned int data_shndx,
 396                                          Output_section* output_section,
 397                                          const elfcpp::Rela<64, false>& reloc,
 398                                          unsigned int r_type,
 399                                          Symbol* gsym);
 400
 401   private:
 402     static void
 403     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 404
 405     static void
 406     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 407                              Symbol*);
 408
 409     void
 410     check_non_pic(Relobj*, unsigned int r_type);
 411
 412     inline bool
 413     possible_function_pointer_reloc(unsigned int r_type);
 414
 415     bool
 416     reloc_needs_plt_for_ifunc(Sized_relobj<64, false>*, unsigned int r_type);
 417
 418     // Whether we have issued an error about a non-PIC compilation.
 419     bool issued_non_pic_error_;
 420   };
 421
 422   // The class which implements relocation.
 423   class Relocate
 424   {
 425    public:
 426     Relocate()
 427       : skip_call_tls_get_addr_(false)
 428     { }
 429
 430     ~Relocate()
 431     {
 432       if (this->skip_call_tls_get_addr_)
 433         {
 434           // FIXME: This needs to specify the location somehow.
 435           gold_error(_("missing expected TLS relocation"));
 436         }
 437     }
 438
 439     // Do a relocation.  Return false if the caller should not issue
 440     // any warnings about this relocation.
 441     inline bool
 442     relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
 443              size_t relnum, const elfcpp::Rela<64, false>&,
 444              unsigned int r_type, const Sized_symbol<64>*,
 445              const Symbol_value<64>*,
 446              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 447              section_size_type);
 448
 449    private:
 450     // Do a TLS relocation.
 451     inline void
 452     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 453                  size_t relnum, const elfcpp::Rela<64, false>&,
 454                  unsigned int r_type, const Sized_symbol<64>*,
 455                  const Symbol_value<64>*,
 456                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 457                  section_size_type);
 458
 459     // Do a TLS General-Dynamic to Initial-Exec transition.
 460     inline void
 461     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 462                  Output_segment* tls_segment,
 463                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 464                  elfcpp::Elf_types<64>::Elf_Addr value,
 465                  unsigned char* view,
 466                  elfcpp::Elf_types<64>::Elf_Addr,
 467                  section_size_type view_size);
 468
 469     // Do a TLS General-Dynamic to Local-Exec transition.
 470     inline void
 471     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 472                  Output_segment* tls_segment,
 473                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 474                  elfcpp::Elf_types<64>::Elf_Addr value,
 475                  unsigned char* view,
 476                  section_size_type view_size);
 477
 478     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 479     inline void
 480     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 481                       Output_segment* tls_segment,
 482                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 483                       elfcpp::Elf_types<64>::Elf_Addr value,
 484                       unsigned char* view,
 485                       elfcpp::Elf_types<64>::Elf_Addr,
 486                       section_size_type view_size);
 487
 488     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 489     inline void
 490     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 491                       Output_segment* tls_segment,
 492                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 493                       elfcpp::Elf_types<64>::Elf_Addr value,
 494                       unsigned char* view,
 495                       section_size_type view_size);
 496
 497     // Do a TLS Local-Dynamic to Local-Exec transition.
 498     inline void
 499     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 500                  Output_segment* tls_segment,
 501                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 502                  elfcpp::Elf_types<64>::Elf_Addr value,
 503                  unsigned char* view,
 504                  section_size_type view_size);
 505
 506     // Do a TLS Initial-Exec to Local-Exec transition.
 507     static inline void
 508     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 509                  Output_segment* tls_segment,
 510                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 511                  elfcpp::Elf_types<64>::Elf_Addr value,
 512                  unsigned char* view,
 513                  section_size_type view_size);
 514
 515     // This is set if we should skip the next reloc, which should be a
 516     // PLT32 reloc against ___tls_get_addr.
 517     bool skip_call_tls_get_addr_;
 518   };
 519
 520   // A class which returns the size required for a relocation type,
 521   // used while scanning relocs during a relocatable link.
 522   class Relocatable_size_for_reloc
 523   {
 524    public:
 525     unsigned int
 526     get_size_for_reloc(unsigned int, Relobj*);
 527   };
 528
 529   // Adjust TLS relocation type based on the options and whether this
 530   // is a local symbol.
 531   static tls::Tls_optimization
 532   optimize_tls_reloc(bool is_final, int r_type);
 533
 534   // Get the GOT section, creating it if necessary.
 535   Output_data_got<64, false>*
 536   got_section(Symbol_table*, Layout*);
 537
 538   // Get the GOT PLT section.
 539   Output_data_space*
 540   got_plt_section() const
 541   {
 542     gold_assert(this->got_plt_ != NULL);
 543     return this->got_plt_;
 544   }
 545
 546   // Get the GOT section for TLSDESC entries.
 547   Output_data_got<64, false>*
 548   got_tlsdesc_section() const
 549   {
 550     gold_assert(this->got_tlsdesc_ != NULL);
 551     return this->got_tlsdesc_;
 552   }
 553
 554   // Create the PLT section.
 555   void
 556   make_plt_section(Symbol_table* symtab, Layout* layout);
 557
 558   // Create a PLT entry for a global symbol.
 559   void
 560   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 561
 562   // Create a PLT entry for a local STT_GNU_IFUNC symbol.
 563   void
 564   make_local_ifunc_plt_entry(Symbol_table*, Layout*,
 565                              Sized_relobj<64, false>* relobj,
 566                              unsigned int local_sym_index);
 567
 568   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 569   void
 570   define_tls_base_symbol(Symbol_table*, Layout*);
 571
 572   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 573   void
 574   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 575
 576   // Create a GOT entry for the TLS module index.
 577   unsigned int
 578   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 579                       Sized_relobj<64, false>* object);
 580
 581   // Get the PLT section.
 582   Output_data_plt_x86_64*
 583   plt_section() const
 584   {
 585     gold_assert(this->plt_ != NULL);
 586     return this->plt_;
 587   }
 588
 589   // Get the dynamic reloc section, creating it if necessary.
 590   Reloc_section*
 591   rela_dyn_section(Layout*);
 592
 593   // Get the section to use for TLSDESC relocations.
 594   Reloc_section*
 595   rela_tlsdesc_section(Layout*) const;
 596
 597   // Add a potential copy relocation.
 598   void
 599   copy_reloc(Symbol_table* symtab, Layout* layout,
 600              Sized_relobj<64, false>* object,
 601              unsigned int shndx, Output_section* output_section,
 602              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 603   {
 604     this->copy_relocs_.copy_reloc(symtab, layout,
 605                                   symtab->get_sized_symbol<64>(sym),
 606                                   object, shndx, output_section,
 607                                   reloc, this->rela_dyn_section(layout));
 608   }
 609
 610   // Information about this specific target which we pass to the
 611   // general Target structure.
 612   static const Target::Target_info x86_64_info;
 613
 614   // The types of GOT entries needed for this platform.
 615   // These values are exposed to the ABI in an incremental link.
 616   // Do not renumber existing values without changing the version
 617   // number of the .gnu_incremental_inputs section.
 618   enum Got_type
 619   {
 620     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 621     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 622     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 623     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 624   };
 625
 626   // This type is used as the argument to the target specific
 627   // relocation routines.  The only target specific reloc is
 628   // R_X86_64_TLSDESC against a local symbol.
 629   struct Tlsdesc_info
 630   {
 631     Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym)
 632       : object(a_object), r_sym(a_r_sym)
 633     { }
 634
 635     // The object in which the local symbol is defined.
 636     Sized_relobj<64, false>* object;
 637     // The local symbol index in the object.
 638     unsigned int r_sym;
 639   };
 640
 641   // The GOT section.
 642   Output_data_got<64, false>* got_;
 643   // The PLT section.
 644   Output_data_plt_x86_64* plt_;
 645   // The GOT PLT section.
 646   Output_data_space* got_plt_;
 647   // The GOT section for TLSDESC relocations.
 648   Output_data_got<64, false>* got_tlsdesc_;
 649   // The _GLOBAL_OFFSET_TABLE_ symbol.
 650   Symbol* global_offset_table_;
 651   // The dynamic reloc section.
 652   Reloc_section* rela_dyn_;
 653   // Relocs saved to avoid a COPY reloc.
 654   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 655   // Space for variables copied with a COPY reloc.
 656   Output_data_space* dynbss_;
 657   // Offset of the GOT entry for the TLS module index.
 658   unsigned int got_mod_index_offset_;
 659   // We handle R_X86_64_TLSDESC against a local symbol as a target
 660   // specific relocation.  Here we store the object and local symbol
 661   // index for the relocation.
 662   std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
 663   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 664   bool tls_base_symbol_defined_;
 665 };
 666
 667 const Target::Target_info Target_x86_64::x86_64_info =
 668 {
 669   64,                   // size
 670   false,                // is_big_endian
 671   elfcpp::EM_X86_64,    // machine_code
 672   false,                // has_make_symbol
 673   false,                // has_resolve
 674   true,                 // has_code_fill
 675   true,                 // is_default_stack_executable
 676   '\0',                 // wrap_char
 677   "/lib/ld64.so.1",     // program interpreter
 678   0x400000,             // default_text_segment_address
 679   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 680   0x1000,               // common_pagesize (overridable by -z common-page-size)
 681   elfcpp::SHN_UNDEF,    // small_common_shndx
 682   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 683   0,                    // small_common_section_flags
 684   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 685   NULL,                 // attributes_section
 686   NULL                  // attributes_vendor
 687 };
 688
 689 // This is called when a new output section is created.  This is where
 690 // we handle the SHF_X86_64_LARGE.
 691
 692 void
 693 Target_x86_64::do_new_output_section(Output_section* os) const
 694 {
 695   if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
 696     os->set_is_large_section();
 697 }
 698
 699 // Get the GOT section, creating it if necessary.
 700
 701 Output_data_got<64, false>*
 702 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 703 {
 704   if (this->got_ == NULL)
 705     {
 706       gold_assert(symtab != NULL && layout != NULL);
 707
 708       this->got_ = new Output_data_got<64, false>();
 709
 710       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 711                                       (elfcpp::SHF_ALLOC
 712                                        | elfcpp::SHF_WRITE),
 713                                       this->got_, ORDER_RELRO_LAST,
 714                                       true);
 715
 716       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 717       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 718                                       (elfcpp::SHF_ALLOC
 719                                        | elfcpp::SHF_WRITE),
 720                                       this->got_plt_, ORDER_NON_RELRO_FIRST,
 721                                       false);
 722
 723       // The first three entries are reserved.
 724       this->got_plt_->set_current_data_size(3 * 8);
 725
 726       // Those bytes can go into the relro segment.
 727       layout->increase_relro(3 * 8);
 728
 729       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 730       this->global_offset_table_ =
 731         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 732                                       Symbol_table::PREDEFINED,
 733                                       this->got_plt_,
 734                                       0, 0, elfcpp::STT_OBJECT,
 735                                       elfcpp::STB_LOCAL,
 736                                       elfcpp::STV_HIDDEN, 0,
 737                                       false, false);
 738
 739       // If there are any TLSDESC relocations, they get GOT entries in
 740       // .got.plt after the jump slot entries.
 741       this->got_tlsdesc_ = new Output_data_got<64, false>();
 742       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 743                                       (elfcpp::SHF_ALLOC
 744                                        | elfcpp::SHF_WRITE),
 745                                       this->got_tlsdesc_,
 746                                       ORDER_NON_RELRO_FIRST, false);
 747     }
 748
 749   return this->got_;
 750 }
 751
 752 // Get the dynamic reloc section, creating it if necessary.
 753
 754 Target_x86_64::Reloc_section*
 755 Target_x86_64::rela_dyn_section(Layout* layout)
 756 {
 757   if (this->rela_dyn_ == NULL)
 758     {
 759       gold_assert(layout != NULL);
 760       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 761       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 762                                       elfcpp::SHF_ALLOC, this->rela_dyn_,
 763                                       ORDER_DYNAMIC_RELOCS, false);
 764     }
 765   return this->rela_dyn_;
 766 }
 767
 768 // Create the PLT section.  The ordinary .got section is an argument,
 769 // since we need to refer to the start.  We also create our own .got
 770 // section just for PLT entries.
 771
 772 Output_data_plt_x86_64::Output_data_plt_x86_64(Symbol_table* symtab,
 773                                                Layout* layout,
 774                                                Output_data_got<64, false>* got,
 775                                                Output_data_space* got_plt)
 776   : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
 777     count_(0), tlsdesc_got_offset_(-1U)
 778 {
 779   this->rel_ = new Reloc_section(false);
 780   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 781                                   elfcpp::SHF_ALLOC, this->rel_,
 782                                   ORDER_DYNAMIC_PLT_RELOCS, false);
 783
 784   if (parameters->doing_static_link())
 785     {
 786       // A statically linked executable will only have a .rela.plt
 787       // section to hold R_X86_64_IRELATIVE relocs for STT_GNU_IFUNC
 788       // symbols.  The library will use these symbols to locate the
 789       // IRELATIVE relocs at program startup time.
 790       symtab->define_in_output_data("__rela_iplt_start", NULL,
 791                                     Symbol_table::PREDEFINED,
 792                                     this->rel_, 0, 0, elfcpp::STT_NOTYPE,
 793                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
 794                                     0, false, true);
 795       symtab->define_in_output_data("__rela_iplt_end", NULL,
 796                                     Symbol_table::PREDEFINED,
 797                                     this->rel_, 0, 0, elfcpp::STT_NOTYPE,
 798                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
 799                                     0, true, true);
 800     }
 801 }
 802
 803 void
 804 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 805 {
 806   os->set_entsize(plt_entry_size);
 807 }
 808
 809 // Add an entry to the PLT.
 810
 811 void
 812 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 813 {
 814   gold_assert(!gsym->has_plt_offset());
 815
 816   // Note that when setting the PLT offset we skip the initial
 817   // reserved PLT entry.
 818   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 819
 820   ++this->count_;
 821
 822   section_offset_type got_offset = this->got_plt_->current_data_size();
 823
 824   // Every PLT entry needs a GOT entry which points back to the PLT
 825   // entry (this will be changed by the dynamic linker, normally
 826   // lazily when the function is called).
 827   this->got_plt_->set_current_data_size(got_offset + 8);
 828
 829   // Every PLT entry needs a reloc.
 830   if (gsym->type() == elfcpp::STT_GNU_IFUNC
 831       && gsym->can_use_relative_reloc(false))
 832     this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
 833                                              this->got_plt_, got_offset, 0);
 834   else
 835     {
 836       gsym->set_needs_dynsym_entry();
 837       this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 838                              got_offset, 0);
 839     }
 840
 841   // Note that we don't need to save the symbol.  The contents of the
 842   // PLT are independent of which symbols are used.  The symbols only
 843   // appear in the relocations.
 844 }
 845
 846 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.  Return
 847 // the PLT offset.
 848
 849 unsigned int
 850 Output_data_plt_x86_64::add_local_ifunc_entry(Sized_relobj<64, false>* relobj,
 851                                               unsigned int local_sym_index)
 852 {
 853   unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
 854   ++this->count_;
 855
 856   section_offset_type got_offset = this->got_plt_->current_data_size();
 857
 858   // Every PLT entry needs a GOT entry which points back to the PLT
 859   // entry.
 860   this->got_plt_->set_current_data_size(got_offset + 8);
 861
 862   // Every PLT entry needs a reloc.
 863   this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
 864                                           elfcpp::R_X86_64_IRELATIVE,
 865                                           this->got_plt_, got_offset, 0);
 866
 867   return plt_offset;
 868 }
 869
 870 // Return where the TLSDESC relocations should go, creating it if
 871 // necessary.  These follow the JUMP_SLOT relocations.
 872
 873 Output_data_plt_x86_64::Reloc_section*
 874 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
 875 {
 876   if (this->tlsdesc_rel_ == NULL)
 877     {
 878       this->tlsdesc_rel_ = new Reloc_section(false);
 879       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 880                                       elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
 881                                       ORDER_DYNAMIC_PLT_RELOCS, false);
 882       gold_assert(this->tlsdesc_rel_->output_section() ==
 883                   this->rel_->output_section());
 884     }
 885   return this->tlsdesc_rel_;
 886 }
 887
 888 // Set the final size.
 889 void
 890 Output_data_plt_x86_64::set_final_data_size()
 891 {
 892   unsigned int count = this->count_;
 893   if (this->has_tlsdesc_entry())
 894     ++count;
 895   this->set_data_size((count + 1) * plt_entry_size);
 896 }
 897
 898 // The first entry in the PLT for an executable.
 899
 900 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 901 {
 902   // From AMD64 ABI Draft 0.98, page 76
 903   0xff, 0x35,   // pushq contents of memory address
 904   0, 0, 0, 0,   // replaced with address of .got + 8
 905   0xff, 0x25,   // jmp indirect
 906   0, 0, 0, 0,   // replaced with address of .got + 16
 907   0x90, 0x90, 0x90, 0x90   // noop (x4)
 908 };
 909
 910 // Subsequent entries in the PLT for an executable.
 911
 912 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 913 {
 914   // From AMD64 ABI Draft 0.98, page 76
 915   0xff, 0x25,   // jmpq indirect
 916   0, 0, 0, 0,   // replaced with address of symbol in .got
 917   0x68,         // pushq immediate
 918   0, 0, 0, 0,   // replaced with offset into relocation table
 919   0xe9,         // jmpq relative
 920   0, 0, 0, 0    // replaced with offset to start of .plt
 921 };
 922
 923 // The reserved TLSDESC entry in the PLT for an executable.
 924
 925 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 926 {
 927   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 928   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 929   0xff, 0x35,   // pushq x(%rip)
 930   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 931   0xff, 0x25,   // jmpq *y(%rip)
 932   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 933   0x0f, 0x1f,   // nop
 934   0x40, 0
 935 };
 936
 937 // Write out the PLT.  This uses the hand-coded instructions above,
 938 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 939
 940 void
 941 Output_data_plt_x86_64::do_write(Output_file* of)
 942 {
 943   const off_t offset = this->offset();
 944   const section_size_type oview_size =
 945     convert_to_section_size_type(this->data_size());
 946   unsigned char* const oview = of->get_output_view(offset, oview_size);
 947
 948   const off_t got_file_offset = this->got_plt_->offset();
 949   const section_size_type got_size =
 950     convert_to_section_size_type(this->got_plt_->data_size());
 951   unsigned char* const got_view = of->get_output_view(got_file_offset,
 952                                                       got_size);
 953
 954   unsigned char* pov = oview;
 955
 956   // The base address of the .plt section.
 957   elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
 958   // The base address of the .got section.
 959   elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
 960   // The base address of the PLT portion of the .got section,
 961   // which is where the GOT pointer will point, and where the
 962   // three reserved GOT entries are located.
 963   elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
 964
 965   memcpy(pov, first_plt_entry, plt_entry_size);
 966   // We do a jmp relative to the PC at the end of this instruction.
 967   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 968                                               (got_address + 8
 969                                                - (plt_address + 6)));
 970   elfcpp::Swap<32, false>::writeval(pov + 8,
 971                                     (got_address + 16
 972                                      - (plt_address + 12)));
 973   pov += plt_entry_size;
 974
 975   unsigned char* got_pov = got_view;
 976
 977   memset(got_pov, 0, 24);
 978   got_pov += 24;
 979
 980   unsigned int plt_offset = plt_entry_size;
 981   unsigned int got_offset = 24;
 982   const unsigned int count = this->count_;
 983   for (unsigned int plt_index = 0;
 984        plt_index < count;
 985        ++plt_index,
 986          pov += plt_entry_size,
 987          got_pov += 8,
 988          plt_offset += plt_entry_size,
 989          got_offset += 8)
 990     {
 991       // Set and adjust the PLT entry itself.
 992       memcpy(pov, plt_entry, plt_entry_size);
 993       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 994                                                   (got_address + got_offset
 995                                                    - (plt_address + plt_offset
 996                                                       + 6)));
 997
 998       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 999       elfcpp::Swap<32, false>::writeval(pov + 12,
1000                                         - (plt_offset + plt_entry_size));
1001
1002       // Set the entry in the GOT.
1003       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
1004     }
1005
1006   if (this->has_tlsdesc_entry())
1007     {
1008       // Set and adjust the reserved TLSDESC PLT entry.
1009       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
1010       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
1011       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1012                                                   (got_address + 8
1013                                                    - (plt_address + plt_offset
1014                                                       + 6)));
1015       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
1016                                                   (got_base
1017                                                    + tlsdesc_got_offset
1018                                                    - (plt_address + plt_offset
1019                                                       + 12)));
1020       pov += plt_entry_size;
1021     }
1022
1023   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1024   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1025
1026   of->write_output_view(offset, oview_size, oview);
1027   of->write_output_view(got_file_offset, got_size, got_view);
1028 }
1029
1030 // Create the PLT section.
1031
1032 void
1033 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
1034 {
1035   if (this->plt_ == NULL)
1036     {
1037       // Create the GOT sections first.
1038       this->got_section(symtab, layout);
1039
1040       this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
1041                                               this->got_plt_);
1042       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1043                                       (elfcpp::SHF_ALLOC
1044                                        | elfcpp::SHF_EXECINSTR),
1045                                       this->plt_, ORDER_PLT, false);
1046
1047       // Make the sh_info field of .rela.plt point to .plt.
1048       Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1049       rela_plt_os->set_info_section(this->plt_->output_section());
1050     }
1051 }
1052
1053 // Return the section for TLSDESC relocations.
1054
1055 Target_x86_64::Reloc_section*
1056 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
1057 {
1058   return this->plt_section()->rela_tlsdesc(layout);
1059 }
1060
1061 // Create a PLT entry for a global symbol.
1062
1063 void
1064 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
1065                               Symbol* gsym)
1066 {
1067   if (gsym->has_plt_offset())
1068     return;
1069
1070   if (this->plt_ == NULL)
1071     this->make_plt_section(symtab, layout);
1072
1073   this->plt_->add_entry(gsym);
1074 }
1075
1076 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1077
1078 void
1079 Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1080                                           Sized_relobj<64, false>* relobj,
1081                                           unsigned int local_sym_index)
1082 {
1083   if (relobj->local_has_plt_offset(local_sym_index))
1084     return;
1085   if (this->plt_ == NULL)
1086     this->make_plt_section(symtab, layout);
1087   unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj,
1088                                                               local_sym_index);
1089   relobj->set_local_plt_offset(local_sym_index, plt_offset);
1090 }
1091
1092 // Return the number of entries in the PLT.
1093
1094 unsigned int
1095 Target_x86_64::plt_entry_count() const
1096 {
1097   if (this->plt_ == NULL)
1098     return 0;
1099   return this->plt_->entry_count();
1100 }
1101
1102 // Return the offset of the first non-reserved PLT entry.
1103
1104 unsigned int
1105 Target_x86_64::first_plt_entry_offset() const
1106 {
1107   return Output_data_plt_x86_64::first_plt_entry_offset();
1108 }
1109
1110 // Return the size of each PLT entry.
1111
1112 unsigned int
1113 Target_x86_64::plt_entry_size() const
1114 {
1115   return Output_data_plt_x86_64::get_plt_entry_size();
1116 }
1117
1118 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1119
1120 void
1121 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1122 {
1123   if (this->tls_base_symbol_defined_)
1124     return;
1125
1126   Output_segment* tls_segment = layout->tls_segment();
1127   if (tls_segment != NULL)
1128     {
1129       bool is_exec = parameters->options().output_is_executable();
1130       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1131                                        Symbol_table::PREDEFINED,
1132                                        tls_segment, 0, 0,
1133                                        elfcpp::STT_TLS,
1134                                        elfcpp::STB_LOCAL,
1135                                        elfcpp::STV_HIDDEN, 0,
1136                                        (is_exec
1137                                         ? Symbol::SEGMENT_END
1138                                         : Symbol::SEGMENT_START),
1139                                        true);
1140     }
1141   this->tls_base_symbol_defined_ = true;
1142 }
1143
1144 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1145
1146 void
1147 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
1148                                              Layout* layout)
1149 {
1150   if (this->plt_ == NULL)
1151     this->make_plt_section(symtab, layout);
1152
1153   if (!this->plt_->has_tlsdesc_entry())
1154     {
1155       // Allocate the TLSDESC_GOT entry.
1156       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1157       unsigned int got_offset = got->add_constant(0);
1158
1159       // Allocate the TLSDESC_PLT entry.
1160       this->plt_->reserve_tlsdesc_entry(got_offset);
1161     }
1162 }
1163
1164 // Create a GOT entry for the TLS module index.
1165
1166 unsigned int
1167 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1168                                    Sized_relobj<64, false>* object)
1169 {
1170   if (this->got_mod_index_offset_ == -1U)
1171     {
1172       gold_assert(symtab != NULL && layout != NULL && object != NULL);
1173       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1174       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1175       unsigned int got_offset = got->add_constant(0);
1176       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1177                           got_offset, 0);
1178       got->add_constant(0);
1179       this->got_mod_index_offset_ = got_offset;
1180     }
1181   return this->got_mod_index_offset_;
1182 }
1183
1184 // Optimize the TLS relocation type based on what we know about the
1185 // symbol.  IS_FINAL is true if the final address of this symbol is
1186 // known at link time.
1187
1188 tls::Tls_optimization
1189 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1190 {
1191   // If we are generating a shared library, then we can't do anything
1192   // in the linker.
1193   if (parameters->options().shared())
1194     return tls::TLSOPT_NONE;
1195
1196   switch (r_type)
1197     {
1198     case elfcpp::R_X86_64_TLSGD:
1199     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1200     case elfcpp::R_X86_64_TLSDESC_CALL:
1201       // These are General-Dynamic which permits fully general TLS
1202       // access.  Since we know that we are generating an executable,
1203       // we can convert this to Initial-Exec.  If we also know that
1204       // this is a local symbol, we can further switch to Local-Exec.
1205       if (is_final)
1206         return tls::TLSOPT_TO_LE;
1207       return tls::TLSOPT_TO_IE;
1208
1209     case elfcpp::R_X86_64_TLSLD:
1210       // This is Local-Dynamic, which refers to a local symbol in the
1211       // dynamic TLS block.  Since we know that we generating an
1212       // executable, we can switch to Local-Exec.
1213       return tls::TLSOPT_TO_LE;
1214
1215     case elfcpp::R_X86_64_DTPOFF32:
1216     case elfcpp::R_X86_64_DTPOFF64:
1217       // Another Local-Dynamic reloc.
1218       return tls::TLSOPT_TO_LE;
1219
1220     case elfcpp::R_X86_64_GOTTPOFF:
1221       // These are Initial-Exec relocs which get the thread offset
1222       // from the GOT.  If we know that we are linking against the
1223       // local symbol, we can switch to Local-Exec, which links the
1224       // thread offset into the instruction.
1225       if (is_final)
1226         return tls::TLSOPT_TO_LE;
1227       return tls::TLSOPT_NONE;
1228
1229     case elfcpp::R_X86_64_TPOFF32:
1230       // When we already have Local-Exec, there is nothing further we
1231       // can do.
1232       return tls::TLSOPT_NONE;
1233
1234     default:
1235       gold_unreachable();
1236     }
1237 }
1238
1239 // Report an unsupported relocation against a local symbol.
1240
1241 void
1242 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
1243                                              unsigned int r_type)
1244 {
1245   gold_error(_("%s: unsupported reloc %u against local symbol"),
1246              object->name().c_str(), r_type);
1247 }
1248
1249 // We are about to emit a dynamic relocation of type R_TYPE.  If the
1250 // dynamic linker does not support it, issue an error.  The GNU linker
1251 // only issues a non-PIC error for an allocated read-only section.
1252 // Here we know the section is allocated, but we don't know that it is
1253 // read-only.  But we check for all the relocation types which the
1254 // glibc dynamic linker supports, so it seems appropriate to issue an
1255 // error even if the section is not read-only.
1256
1257 void
1258 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
1259 {
1260   switch (r_type)
1261     {
1262       // These are the relocation types supported by glibc for x86_64.
1263     case elfcpp::R_X86_64_RELATIVE:
1264     case elfcpp::R_X86_64_IRELATIVE:
1265     case elfcpp::R_X86_64_GLOB_DAT:
1266     case elfcpp::R_X86_64_JUMP_SLOT:
1267     case elfcpp::R_X86_64_DTPMOD64:
1268     case elfcpp::R_X86_64_DTPOFF64:
1269     case elfcpp::R_X86_64_TPOFF64:
1270     case elfcpp::R_X86_64_64:
1271     case elfcpp::R_X86_64_32:
1272     case elfcpp::R_X86_64_PC32:
1273     case elfcpp::R_X86_64_COPY:
1274       return;
1275
1276     default:
1277       // This prevents us from issuing more than one error per reloc
1278       // section.  But we can still wind up issuing more than one
1279       // error per object file.
1280       if (this->issued_non_pic_error_)
1281         return;
1282       gold_assert(parameters->options().output_is_position_independent());
1283       object->error(_("requires unsupported dynamic reloc; "
1284                       "recompile with -fPIC"));
1285       this->issued_non_pic_error_ = true;
1286       return;
1287
1288     case elfcpp::R_X86_64_NONE:
1289       gold_unreachable();
1290     }
1291 }
1292
1293 // Return whether we need to make a PLT entry for a relocation of the
1294 // given type against a STT_GNU_IFUNC symbol.
1295
1296 bool
1297 Target_x86_64::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<64, false>* object,
1298                                                unsigned int r_type)
1299 {
1300   switch (r_type)
1301     {
1302     case elfcpp::R_X86_64_NONE:
1303     case elfcpp::R_X86_64_GNU_VTINHERIT:
1304     case elfcpp::R_X86_64_GNU_VTENTRY:
1305       return false;
1306
1307     case elfcpp::R_X86_64_64:
1308     case elfcpp::R_X86_64_32:
1309     case elfcpp::R_X86_64_32S:
1310     case elfcpp::R_X86_64_16:
1311     case elfcpp::R_X86_64_8:
1312     case elfcpp::R_X86_64_PC64:
1313     case elfcpp::R_X86_64_PC32:
1314     case elfcpp::R_X86_64_PC16:
1315     case elfcpp::R_X86_64_PC8:
1316     case elfcpp::R_X86_64_PLT32:
1317     case elfcpp::R_X86_64_GOTPC32:
1318     case elfcpp::R_X86_64_GOTOFF64:
1319     case elfcpp::R_X86_64_GOTPC64:
1320     case elfcpp::R_X86_64_PLTOFF64:
1321     case elfcpp::R_X86_64_GOT64:
1322     case elfcpp::R_X86_64_GOT32:
1323     case elfcpp::R_X86_64_GOTPCREL64:
1324     case elfcpp::R_X86_64_GOTPCREL:
1325     case elfcpp::R_X86_64_GOTPLT64:
1326       return true;
1327
1328     case elfcpp::R_X86_64_COPY:
1329     case elfcpp::R_X86_64_GLOB_DAT:
1330     case elfcpp::R_X86_64_JUMP_SLOT:
1331     case elfcpp::R_X86_64_RELATIVE:
1332     case elfcpp::R_X86_64_IRELATIVE:
1333     case elfcpp::R_X86_64_TPOFF64:
1334     case elfcpp::R_X86_64_DTPMOD64:
1335     case elfcpp::R_X86_64_TLSDESC:
1336       // We will give an error later.
1337       return false;
1338
1339     case elfcpp::R_X86_64_TLSGD:
1340     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1341     case elfcpp::R_X86_64_TLSDESC_CALL:
1342     case elfcpp::R_X86_64_TLSLD:
1343     case elfcpp::R_X86_64_DTPOFF32:
1344     case elfcpp::R_X86_64_DTPOFF64:
1345     case elfcpp::R_X86_64_GOTTPOFF:
1346     case elfcpp::R_X86_64_TPOFF32:
1347       gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1348                  object->name().c_str(), r_type);
1349       return false;
1350
1351     case elfcpp::R_X86_64_SIZE32:
1352     case elfcpp::R_X86_64_SIZE64:
1353     default:
1354       // We will give an error later.
1355       return false;
1356     }
1357 }
1358
1359 // Scan a relocation for a local symbol.
1360
1361 inline void
1362 Target_x86_64::Scan::local(Symbol_table* symtab,
1363                            Layout* layout,
1364                            Target_x86_64* target,
1365                            Sized_relobj<64, false>* object,
1366                            unsigned int data_shndx,
1367                            Output_section* output_section,
1368                            const elfcpp::Rela<64, false>& reloc,
1369                            unsigned int r_type,
1370                            const elfcpp::Sym<64, false>& lsym)
1371 {
1372   // A local STT_GNU_IFUNC symbol may require a PLT entry.
1373   if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1374       && this->reloc_needs_plt_for_ifunc(object, r_type))
1375     {
1376       unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1377       target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1378     }
1379
1380   switch (r_type)
1381     {
1382     case elfcpp::R_X86_64_NONE:
1383     case elfcpp::R_X86_64_GNU_VTINHERIT:
1384     case elfcpp::R_X86_64_GNU_VTENTRY:
1385       break;
1386
1387     case elfcpp::R_X86_64_64:
1388       // If building a shared library (or a position-independent
1389       // executable), we need to create a dynamic relocation for this
1390       // location.  The relocation applied at link time will apply the
1391       // link-time value, so we flag the location with an
1392       // R_X86_64_RELATIVE relocation so the dynamic loader can
1393       // relocate it easily.
1394       if (parameters->options().output_is_position_independent())
1395         {
1396           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1397           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1398           rela_dyn->add_local_relative(object, r_sym,
1399                                        elfcpp::R_X86_64_RELATIVE,
1400                                        output_section, data_shndx,
1401                                        reloc.get_r_offset(),
1402                                        reloc.get_r_addend());
1403         }
1404       break;
1405
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       // If building a shared library (or a position-independent
1411       // executable), we need to create a dynamic relocation for this
1412       // location.  We can't use an R_X86_64_RELATIVE relocation
1413       // because that is always a 64-bit relocation.
1414       if (parameters->options().output_is_position_independent())
1415         {
1416           this->check_non_pic(object, r_type);
1417
1418           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1419           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1420           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1421             rela_dyn->add_local(object, r_sym, r_type, output_section,
1422                                 data_shndx, reloc.get_r_offset(),
1423                                 reloc.get_r_addend());
1424           else
1425             {
1426               gold_assert(lsym.get_st_value() == 0);
1427               unsigned int shndx = lsym.get_st_shndx();
1428               bool is_ordinary;
1429               shndx = object->adjust_sym_shndx(r_sym, shndx,
1430                                                &is_ordinary);
1431               if (!is_ordinary)
1432                 object->error(_("section symbol %u has bad shndx %u"),
1433                               r_sym, shndx);
1434               else
1435                 rela_dyn->add_local_section(object, shndx,
1436                                             r_type, output_section,
1437                                             data_shndx, reloc.get_r_offset(),
1438                                             reloc.get_r_addend());
1439             }
1440         }
1441       break;
1442
1443     case elfcpp::R_X86_64_PC64:
1444     case elfcpp::R_X86_64_PC32:
1445     case elfcpp::R_X86_64_PC16:
1446     case elfcpp::R_X86_64_PC8:
1447       break;
1448
1449     case elfcpp::R_X86_64_PLT32:
1450       // Since we know this is a local symbol, we can handle this as a
1451       // PC32 reloc.
1452       break;
1453
1454     case elfcpp::R_X86_64_GOTPC32:
1455     case elfcpp::R_X86_64_GOTOFF64:
1456     case elfcpp::R_X86_64_GOTPC64:
1457     case elfcpp::R_X86_64_PLTOFF64:
1458       // We need a GOT section.
1459       target->got_section(symtab, layout);
1460       // For PLTOFF64, we'd normally want a PLT section, but since we
1461       // know this is a local symbol, no PLT is needed.
1462       break;
1463
1464     case elfcpp::R_X86_64_GOT64:
1465     case elfcpp::R_X86_64_GOT32:
1466     case elfcpp::R_X86_64_GOTPCREL64:
1467     case elfcpp::R_X86_64_GOTPCREL:
1468     case elfcpp::R_X86_64_GOTPLT64:
1469       {
1470         // The symbol requires a GOT entry.
1471         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1472         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1473
1474         // For a STT_GNU_IFUNC symbol we want the PLT offset.  That
1475         // lets function pointers compare correctly with shared
1476         // libraries.  Otherwise we would need an IRELATIVE reloc.
1477         bool is_new;
1478         if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1479           is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1480         else
1481           is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1482         if (is_new)
1483           {
1484             // If we are generating a shared object, we need to add a
1485             // dynamic relocation for this symbol's GOT entry.
1486             if (parameters->options().output_is_position_independent())
1487               {
1488                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1489                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1490                 if (r_type != elfcpp::R_X86_64_GOT32)
1491                   {
1492                     unsigned int got_offset =
1493                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1494                     rela_dyn->add_local_relative(object, r_sym,
1495                                                  elfcpp::R_X86_64_RELATIVE,
1496                                                  got, got_offset, 0);
1497                   }
1498                 else
1499                   {
1500                     this->check_non_pic(object, r_type);
1501
1502                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1503                     rela_dyn->add_local(
1504                         object, r_sym, r_type, got,
1505                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1506                   }
1507               }
1508           }
1509         // For GOTPLT64, we'd normally want a PLT section, but since
1510         // we know this is a local symbol, no PLT is needed.
1511       }
1512       break;
1513
1514     case elfcpp::R_X86_64_COPY:
1515     case elfcpp::R_X86_64_GLOB_DAT:
1516     case elfcpp::R_X86_64_JUMP_SLOT:
1517     case elfcpp::R_X86_64_RELATIVE:
1518     case elfcpp::R_X86_64_IRELATIVE:
1519       // These are outstanding tls relocs, which are unexpected when linking
1520     case elfcpp::R_X86_64_TPOFF64:
1521     case elfcpp::R_X86_64_DTPMOD64:
1522     case elfcpp::R_X86_64_TLSDESC:
1523       gold_error(_("%s: unexpected reloc %u in object file"),
1524                  object->name().c_str(), r_type);
1525       break;
1526
1527       // These are initial tls relocs, which are expected when linking
1528     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1529     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1530     case elfcpp::R_X86_64_TLSDESC_CALL:
1531     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1532     case elfcpp::R_X86_64_DTPOFF32:
1533     case elfcpp::R_X86_64_DTPOFF64:
1534     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1535     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1536       {
1537         bool output_is_shared = parameters->options().shared();
1538         const tls::Tls_optimization optimized_type
1539             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1540         switch (r_type)
1541           {
1542           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1543             if (optimized_type == tls::TLSOPT_NONE)
1544               {
1545                 // Create a pair of GOT entries for the module index and
1546                 // dtv-relative offset.
1547                 Output_data_got<64, false>* got
1548                     = target->got_section(symtab, layout);
1549                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1550                 unsigned int shndx = lsym.get_st_shndx();
1551                 bool is_ordinary;
1552                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1553                 if (!is_ordinary)
1554                   object->error(_("local symbol %u has bad shndx %u"),
1555                               r_sym, shndx);
1556                 else
1557                   got->add_local_pair_with_rela(object, r_sym,
1558                                                 shndx,
1559                                                 GOT_TYPE_TLS_PAIR,
1560                                                 target->rela_dyn_section(layout),
1561                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1562               }
1563             else if (optimized_type != tls::TLSOPT_TO_LE)
1564               unsupported_reloc_local(object, r_type);
1565             break;
1566
1567           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1568             target->define_tls_base_symbol(symtab, layout);
1569             if (optimized_type == tls::TLSOPT_NONE)
1570               {
1571                 // Create reserved PLT and GOT entries for the resolver.
1572                 target->reserve_tlsdesc_entries(symtab, layout);
1573
1574                 // Generate a double GOT entry with an
1575                 // R_X86_64_TLSDESC reloc.  The R_X86_64_TLSDESC reloc
1576                 // is resolved lazily, so the GOT entry needs to be in
1577                 // an area in .got.plt, not .got.  Call got_section to
1578                 // make sure the section has been created.
1579                 target->got_section(symtab, layout);
1580                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1581                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1582                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1583                   {
1584                     unsigned int got_offset = got->add_constant(0);
1585                     got->add_constant(0);
1586                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1587                                                  got_offset);
1588                     Reloc_section* rt = target->rela_tlsdesc_section(layout);
1589                     // We store the arguments we need in a vector, and
1590                     // use the index into the vector as the parameter
1591                     // to pass to the target specific routines.
1592                     uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
1593                     void* arg = reinterpret_cast<void*>(intarg);
1594                     rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1595                                             got, got_offset, 0);
1596                   }
1597               }
1598             else if (optimized_type != tls::TLSOPT_TO_LE)
1599               unsupported_reloc_local(object, r_type);
1600             break;
1601
1602           case elfcpp::R_X86_64_TLSDESC_CALL:
1603             break;
1604
1605           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1606             if (optimized_type == tls::TLSOPT_NONE)
1607               {
1608                 // Create a GOT entry for the module index.
1609                 target->got_mod_index_entry(symtab, layout, object);
1610               }
1611             else if (optimized_type != tls::TLSOPT_TO_LE)
1612               unsupported_reloc_local(object, r_type);
1613             break;
1614
1615           case elfcpp::R_X86_64_DTPOFF32:
1616           case elfcpp::R_X86_64_DTPOFF64:
1617             break;
1618
1619           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1620             layout->set_has_static_tls();
1621             if (optimized_type == tls::TLSOPT_NONE)
1622               {
1623                 // Create a GOT entry for the tp-relative offset.
1624                 Output_data_got<64, false>* got
1625                     = target->got_section(symtab, layout);
1626                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1627                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1628                                          target->rela_dyn_section(layout),
1629                                          elfcpp::R_X86_64_TPOFF64);
1630               }
1631             else if (optimized_type != tls::TLSOPT_TO_LE)
1632               unsupported_reloc_local(object, r_type);
1633             break;
1634
1635           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1636             layout->set_has_static_tls();
1637             if (output_is_shared)
1638               unsupported_reloc_local(object, r_type);
1639             break;
1640
1641           default:
1642             gold_unreachable();
1643           }
1644       }
1645       break;
1646
1647     case elfcpp::R_X86_64_SIZE32:
1648     case elfcpp::R_X86_64_SIZE64:
1649     default:
1650       gold_error(_("%s: unsupported reloc %u against local symbol"),
1651                  object->name().c_str(), r_type);
1652       break;
1653     }
1654 }
1655
1656
1657 // Report an unsupported relocation against a global symbol.
1658
1659 void
1660 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1661                                               unsigned int r_type,
1662                                               Symbol* gsym)
1663 {
1664   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1665              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1666 }
1667
1668 // Returns true if this relocation type could be that of a function pointer.
1669 inline bool
1670 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
1671 {
1672   switch (r_type)
1673     {
1674     case elfcpp::R_X86_64_64:
1675     case elfcpp::R_X86_64_32:
1676     case elfcpp::R_X86_64_32S:
1677     case elfcpp::R_X86_64_16:
1678     case elfcpp::R_X86_64_8:
1679     case elfcpp::R_X86_64_GOT64:
1680     case elfcpp::R_X86_64_GOT32:
1681     case elfcpp::R_X86_64_GOTPCREL64:
1682     case elfcpp::R_X86_64_GOTPCREL:
1683     case elfcpp::R_X86_64_GOTPLT64:
1684       {
1685         return true;
1686       }
1687     }
1688   return false;
1689 }
1690
1691 // For safe ICF, scan a relocation for a local symbol to check if it
1692 // corresponds to a function pointer being taken.  In that case mark
1693 // the function whose pointer was taken as not foldable.
1694
1695 inline bool
1696 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1697   Symbol_table* ,
1698   Layout* ,
1699   Target_x86_64* ,
1700   Sized_relobj<64, false>* ,
1701   unsigned int ,
1702   Output_section* ,
1703   const elfcpp::Rela<64, false>& ,
1704   unsigned int r_type,
1705   const elfcpp::Sym<64, false>&)
1706 {
1707   // When building a shared library, do not fold any local symbols as it is
1708   // not possible to distinguish pointer taken versus a call by looking at
1709   // the relocation types.
1710   return (parameters->options().shared()
1711           || possible_function_pointer_reloc(r_type));
1712 }
1713
1714 // For safe ICF, scan a relocation for a global symbol to check if it
1715 // corresponds to a function pointer being taken.  In that case mark
1716 // the function whose pointer was taken as not foldable.
1717
1718 inline bool
1719 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1720   Symbol_table*,
1721   Layout* ,
1722   Target_x86_64* ,
1723   Sized_relobj<64, false>* ,
1724   unsigned int ,
1725   Output_section* ,
1726   const elfcpp::Rela<64, false>& ,
1727   unsigned int r_type,
1728   Symbol* gsym)
1729 {
1730   // When building a shared library, do not fold symbols whose visibility
1731   // is hidden, internal or protected.
1732   return ((parameters->options().shared()
1733            && (gsym->visibility() == elfcpp::STV_INTERNAL
1734                || gsym->visibility() == elfcpp::STV_PROTECTED
1735                || gsym->visibility() == elfcpp::STV_HIDDEN))
1736           || possible_function_pointer_reloc(r_type));
1737 }
1738
1739 // Scan a relocation for a global symbol.
1740
1741 inline void
1742 Target_x86_64::Scan::global(Symbol_table* symtab,
1743                             Layout* layout,
1744                             Target_x86_64* target,
1745                             Sized_relobj<64, false>* object,
1746                             unsigned int data_shndx,
1747                             Output_section* output_section,
1748                             const elfcpp::Rela<64, false>& reloc,
1749                             unsigned int r_type,
1750                             Symbol* gsym)
1751 {
1752   // A STT_GNU_IFUNC symbol may require a PLT entry.
1753   if (gsym->type() == elfcpp::STT_GNU_IFUNC
1754       && this->reloc_needs_plt_for_ifunc(object, r_type))
1755     target->make_plt_entry(symtab, layout, gsym);
1756
1757   switch (r_type)
1758     {
1759     case elfcpp::R_X86_64_NONE:
1760     case elfcpp::R_X86_64_GNU_VTINHERIT:
1761     case elfcpp::R_X86_64_GNU_VTENTRY:
1762       break;
1763
1764     case elfcpp::R_X86_64_64:
1765     case elfcpp::R_X86_64_32:
1766     case elfcpp::R_X86_64_32S:
1767     case elfcpp::R_X86_64_16:
1768     case elfcpp::R_X86_64_8:
1769       {
1770         // Make a PLT entry if necessary.
1771         if (gsym->needs_plt_entry())
1772           {
1773             target->make_plt_entry(symtab, layout, gsym);
1774             // Since this is not a PC-relative relocation, we may be
1775             // taking the address of a function. In that case we need to
1776             // set the entry in the dynamic symbol table to the address of
1777             // the PLT entry.
1778             if (gsym->is_from_dynobj() && !parameters->options().shared())
1779               gsym->set_needs_dynsym_value();
1780           }
1781         // Make a dynamic relocation if necessary.
1782         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1783           {
1784             if (gsym->may_need_copy_reloc())
1785               {
1786                 target->copy_reloc(symtab, layout, object,
1787                                    data_shndx, output_section, gsym, reloc);
1788               }
1789             else if (r_type == elfcpp::R_X86_64_64
1790                      && gsym->type() == elfcpp::STT_GNU_IFUNC
1791                      && gsym->can_use_relative_reloc(false)
1792                      && !gsym->is_from_dynobj()
1793                      && !gsym->is_undefined()
1794                      && !gsym->is_preemptible())
1795               {
1796                 // Use an IRELATIVE reloc for a locally defined
1797                 // STT_GNU_IFUNC symbol.  This makes a function
1798                 // address in a PIE executable match the address in a
1799                 // shared library that it links against.
1800                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1801                 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
1802                 rela_dyn->add_symbolless_global_addend(gsym, r_type,
1803                                                        output_section, object,
1804                                                        data_shndx,
1805                                                        reloc.get_r_offset(),
1806                                                        reloc.get_r_addend());
1807               }
1808             else if (r_type == elfcpp::R_X86_64_64
1809                      && gsym->can_use_relative_reloc(false))
1810               {
1811                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1812                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1813                                               output_section, object,
1814                                               data_shndx,
1815                                               reloc.get_r_offset(),
1816                                               reloc.get_r_addend());
1817               }
1818             else
1819               {
1820                 this->check_non_pic(object, r_type);
1821                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1822                 rela_dyn->add_global(gsym, r_type, output_section, object,
1823                                      data_shndx, reloc.get_r_offset(),
1824                                      reloc.get_r_addend());
1825               }
1826           }
1827       }
1828       break;
1829
1830     case elfcpp::R_X86_64_PC64:
1831     case elfcpp::R_X86_64_PC32:
1832     case elfcpp::R_X86_64_PC16:
1833     case elfcpp::R_X86_64_PC8:
1834       {
1835         // Make a PLT entry if necessary.
1836         if (gsym->needs_plt_entry())
1837           target->make_plt_entry(symtab, layout, gsym);
1838         // Make a dynamic relocation if necessary.
1839         int flags = Symbol::NON_PIC_REF;
1840         if (gsym->is_func())
1841           flags |= Symbol::FUNCTION_CALL;
1842         if (gsym->needs_dynamic_reloc(flags))
1843           {
1844             if (gsym->may_need_copy_reloc())
1845               {
1846                 target->copy_reloc(symtab, layout, object,
1847                                    data_shndx, output_section, gsym, reloc);
1848               }
1849             else
1850               {
1851                 this->check_non_pic(object, r_type);
1852                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1853                 rela_dyn->add_global(gsym, r_type, output_section, object,
1854                                      data_shndx, reloc.get_r_offset(),
1855                                      reloc.get_r_addend());
1856               }
1857           }
1858       }
1859       break;
1860
1861     case elfcpp::R_X86_64_GOT64:
1862     case elfcpp::R_X86_64_GOT32:
1863     case elfcpp::R_X86_64_GOTPCREL64:
1864     case elfcpp::R_X86_64_GOTPCREL:
1865     case elfcpp::R_X86_64_GOTPLT64:
1866       {
1867         // The symbol requires a GOT entry.
1868         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1869         if (gsym->final_value_is_known())
1870           {
1871             // For a STT_GNU_IFUNC symbol we want the PLT address.
1872             if (gsym->type() == elfcpp::STT_GNU_IFUNC)
1873               got->add_global_plt(gsym, GOT_TYPE_STANDARD);
1874             else
1875               got->add_global(gsym, GOT_TYPE_STANDARD);
1876           }
1877         else
1878           {
1879             // If this symbol is not fully resolved, we need to add a
1880             // dynamic relocation for it.
1881             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1882             if (gsym->is_from_dynobj()
1883                 || gsym->is_undefined()
1884                 || gsym->is_preemptible()
1885                 || (gsym->type() == elfcpp::STT_GNU_IFUNC
1886                     && parameters->options().output_is_position_independent()))
1887               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1888                                         elfcpp::R_X86_64_GLOB_DAT);
1889             else
1890               {
1891                 // For a STT_GNU_IFUNC symbol we want to write the PLT
1892                 // offset into the GOT, so that function pointer
1893                 // comparisons work correctly.
1894                 bool is_new;
1895                 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
1896                   is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
1897                 else
1898                   {
1899                     is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
1900                     // Tell the dynamic linker to use the PLT address
1901                     // when resolving relocations.
1902                     if (gsym->is_from_dynobj()
1903                         && !parameters->options().shared())
1904                       gsym->set_needs_dynsym_value();
1905                   }
1906                 if (is_new)
1907                   {
1908                     unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
1909                     rela_dyn->add_global_relative(gsym,
1910                                                   elfcpp::R_X86_64_RELATIVE,
1911                                                   got, got_off, 0);
1912                   }
1913               }
1914           }
1915         // For GOTPLT64, we also need a PLT entry (but only if the
1916         // symbol is not fully resolved).
1917         if (r_type == elfcpp::R_X86_64_GOTPLT64
1918             && !gsym->final_value_is_known())
1919           target->make_plt_entry(symtab, layout, gsym);
1920       }
1921       break;
1922
1923     case elfcpp::R_X86_64_PLT32:
1924       // If the symbol is fully resolved, this is just a PC32 reloc.
1925       // Otherwise we need a PLT entry.
1926       if (gsym->final_value_is_known())
1927         break;
1928       // If building a shared library, we can also skip the PLT entry
1929       // if the symbol is defined in the output file and is protected
1930       // or hidden.
1931       if (gsym->is_defined()
1932           && !gsym->is_from_dynobj()
1933           && !gsym->is_preemptible())
1934         break;
1935       target->make_plt_entry(symtab, layout, gsym);
1936       break;
1937
1938     case elfcpp::R_X86_64_GOTPC32:
1939     case elfcpp::R_X86_64_GOTOFF64:
1940     case elfcpp::R_X86_64_GOTPC64:
1941     case elfcpp::R_X86_64_PLTOFF64:
1942       // We need a GOT section.
1943       target->got_section(symtab, layout);
1944       // For PLTOFF64, we also need a PLT entry (but only if the
1945       // symbol is not fully resolved).
1946       if (r_type == elfcpp::R_X86_64_PLTOFF64
1947           && !gsym->final_value_is_known())
1948         target->make_plt_entry(symtab, layout, gsym);
1949       break;
1950
1951     case elfcpp::R_X86_64_COPY:
1952     case elfcpp::R_X86_64_GLOB_DAT:
1953     case elfcpp::R_X86_64_JUMP_SLOT:
1954     case elfcpp::R_X86_64_RELATIVE:
1955     case elfcpp::R_X86_64_IRELATIVE:
1956       // These are outstanding tls relocs, which are unexpected when linking
1957     case elfcpp::R_X86_64_TPOFF64:
1958     case elfcpp::R_X86_64_DTPMOD64:
1959     case elfcpp::R_X86_64_TLSDESC:
1960       gold_error(_("%s: unexpected reloc %u in object file"),
1961                  object->name().c_str(), r_type);
1962       break;
1963
1964       // These are initial tls relocs, which are expected for global()
1965     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1966     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1967     case elfcpp::R_X86_64_TLSDESC_CALL:
1968     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1969     case elfcpp::R_X86_64_DTPOFF32:
1970     case elfcpp::R_X86_64_DTPOFF64:
1971     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1972     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1973       {
1974         const bool is_final = gsym->final_value_is_known();
1975         const tls::Tls_optimization optimized_type
1976             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1977         switch (r_type)
1978           {
1979           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1980             if (optimized_type == tls::TLSOPT_NONE)
1981               {
1982                 // Create a pair of GOT entries for the module index and
1983                 // dtv-relative offset.
1984                 Output_data_got<64, false>* got
1985                     = target->got_section(symtab, layout);
1986                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1987                                                target->rela_dyn_section(layout),
1988                                                elfcpp::R_X86_64_DTPMOD64,
1989                                                elfcpp::R_X86_64_DTPOFF64);
1990               }
1991             else if (optimized_type == tls::TLSOPT_TO_IE)
1992               {
1993                 // Create a GOT entry for the tp-relative offset.
1994                 Output_data_got<64, false>* got
1995                     = target->got_section(symtab, layout);
1996                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1997                                           target->rela_dyn_section(layout),
1998                                           elfcpp::R_X86_64_TPOFF64);
1999               }
2000             else if (optimized_type != tls::TLSOPT_TO_LE)
2001               unsupported_reloc_global(object, r_type, gsym);
2002             break;
2003
2004           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2005             target->define_tls_base_symbol(symtab, layout);
2006             if (optimized_type == tls::TLSOPT_NONE)
2007               {
2008                 // Create reserved PLT and GOT entries for the resolver.
2009                 target->reserve_tlsdesc_entries(symtab, layout);
2010
2011                 // Create a double GOT entry with an R_X86_64_TLSDESC
2012                 // reloc.  The R_X86_64_TLSDESC reloc is resolved
2013                 // lazily, so the GOT entry needs to be in an area in
2014                 // .got.plt, not .got.  Call got_section to make sure
2015                 // the section has been created.
2016                 target->got_section(symtab, layout);
2017                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2018                 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2019                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
2020                                                elfcpp::R_X86_64_TLSDESC, 0);
2021               }
2022             else if (optimized_type == tls::TLSOPT_TO_IE)
2023               {
2024                 // Create a GOT entry for the tp-relative offset.
2025                 Output_data_got<64, false>* got
2026                     = target->got_section(symtab, layout);
2027                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2028                                           target->rela_dyn_section(layout),
2029                                           elfcpp::R_X86_64_TPOFF64);
2030               }
2031             else if (optimized_type != tls::TLSOPT_TO_LE)
2032               unsupported_reloc_global(object, r_type, gsym);
2033             break;
2034
2035           case elfcpp::R_X86_64_TLSDESC_CALL:
2036             break;
2037
2038           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
2039             if (optimized_type == tls::TLSOPT_NONE)
2040               {
2041                 // Create a GOT entry for the module index.
2042                 target->got_mod_index_entry(symtab, layout, object);
2043               }
2044             else if (optimized_type != tls::TLSOPT_TO_LE)
2045               unsupported_reloc_global(object, r_type, gsym);
2046             break;
2047
2048           case elfcpp::R_X86_64_DTPOFF32:
2049           case elfcpp::R_X86_64_DTPOFF64:
2050             break;
2051
2052           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
2053             layout->set_has_static_tls();
2054             if (optimized_type == tls::TLSOPT_NONE)
2055               {
2056                 // Create a GOT entry for the tp-relative offset.
2057                 Output_data_got<64, false>* got
2058                     = target->got_section(symtab, layout);
2059                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2060                                           target->rela_dyn_section(layout),
2061                                           elfcpp::R_X86_64_TPOFF64);
2062               }
2063             else if (optimized_type != tls::TLSOPT_TO_LE)
2064               unsupported_reloc_global(object, r_type, gsym);
2065             break;
2066
2067           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
2068             layout->set_has_static_tls();
2069             if (parameters->options().shared())
2070               unsupported_reloc_local(object, r_type);
2071             break;
2072
2073           default:
2074             gold_unreachable();
2075           }
2076       }
2077       break;
2078
2079     case elfcpp::R_X86_64_SIZE32:
2080     case elfcpp::R_X86_64_SIZE64:
2081     default:
2082       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2083                  object->name().c_str(), r_type,
2084                  gsym->demangled_name().c_str());
2085       break;
2086     }
2087 }
2088
2089 void
2090 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
2091                                  Layout* layout,
2092                                  Sized_relobj<64, false>* object,
2093                                  unsigned int data_shndx,
2094                                  unsigned int sh_type,
2095                                  const unsigned char* prelocs,
2096                                  size_t reloc_count,
2097                                  Output_section* output_section,
2098                                  bool needs_special_offset_handling,
2099                                  size_t local_symbol_count,
2100                                  const unsigned char* plocal_symbols)
2101 {
2102
2103   if (sh_type == elfcpp::SHT_REL)
2104     {
2105       return;
2106     }
2107
2108    gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2109                            Target_x86_64::Scan,
2110                            Target_x86_64::Relocatable_size_for_reloc>(
2111     symtab,
2112     layout,
2113     this,
2114     object,
2115     data_shndx,
2116     prelocs,
2117     reloc_count,
2118     output_section,
2119     needs_special_offset_handling,
2120     local_symbol_count,
2121     plocal_symbols);
2122
2123 }
2124 // Scan relocations for a section.
2125
2126 void
2127 Target_x86_64::scan_relocs(Symbol_table* symtab,
2128                            Layout* layout,
2129                            Sized_relobj<64, false>* object,
2130                            unsigned int data_shndx,
2131                            unsigned int sh_type,
2132                            const unsigned char* prelocs,
2133                            size_t reloc_count,
2134                            Output_section* output_section,
2135                            bool needs_special_offset_handling,
2136                            size_t local_symbol_count,
2137                            const unsigned char* plocal_symbols)
2138 {
2139   if (sh_type == elfcpp::SHT_REL)
2140     {
2141       gold_error(_("%s: unsupported REL reloc section"),
2142                  object->name().c_str());
2143       return;
2144     }
2145
2146   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2147       Target_x86_64::Scan>(
2148     symtab,
2149     layout,
2150     this,
2151     object,
2152     data_shndx,
2153     prelocs,
2154     reloc_count,
2155     output_section,
2156     needs_special_offset_handling,
2157     local_symbol_count,
2158     plocal_symbols);
2159 }
2160
2161 // Finalize the sections.
2162
2163 void
2164 Target_x86_64::do_finalize_sections(
2165     Layout* layout,
2166     const Input_objects*,
2167     Symbol_table* symtab)
2168 {
2169   const Reloc_section* rel_plt = (this->plt_ == NULL
2170                                   ? NULL
2171                                   : this->plt_->rela_plt());
2172   layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
2173                                   this->rela_dyn_, true, false);
2174
2175   // Fill in some more dynamic tags.
2176   Output_data_dynamic* const odyn = layout->dynamic_data();
2177   if (odyn != NULL)
2178     {
2179       if (this->plt_ != NULL
2180           && this->plt_->output_section() != NULL
2181           && this->plt_->has_tlsdesc_entry())
2182         {
2183           unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
2184           unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
2185           this->got_->finalize_data_size();
2186           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
2187                                         this->plt_, plt_offset);
2188           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
2189                                         this->got_, got_offset);
2190         }
2191     }
2192
2193   // Emit any relocs we saved in an attempt to avoid generating COPY
2194   // relocs.
2195   if (this->copy_relocs_.any_saved_relocs())
2196     this->copy_relocs_.emit(this->rela_dyn_section(layout));
2197
2198   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2199   // the .got.plt section.
2200   Symbol* sym = this->global_offset_table_;
2201   if (sym != NULL)
2202     {
2203       uint64_t data_size = this->got_plt_->current_data_size();
2204       symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
2205     }
2206 }
2207
2208 // Perform a relocation.
2209
2210 inline bool
2211 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
2212                                   Target_x86_64* target,
2213                                   Output_section*,
2214                                   size_t relnum,
2215                                   const elfcpp::Rela<64, false>& rela,
2216                                   unsigned int r_type,
2217                                   const Sized_symbol<64>* gsym,
2218                                   const Symbol_value<64>* psymval,
2219                                   unsigned char* view,
2220                                   elfcpp::Elf_types<64>::Elf_Addr address,
2221                                   section_size_type view_size)
2222 {
2223   if (this->skip_call_tls_get_addr_)
2224     {
2225       if ((r_type != elfcpp::R_X86_64_PLT32
2226            && r_type != elfcpp::R_X86_64_PC32)
2227           || gsym == NULL
2228           || strcmp(gsym->name(), "__tls_get_addr") != 0)
2229         {
2230           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2231                                  _("missing expected TLS relocation"));
2232         }
2233       else
2234         {
2235           this->skip_call_tls_get_addr_ = false;
2236           return false;
2237         }
2238     }
2239
2240   const Sized_relobj<64, false>* object = relinfo->object;
2241
2242   // Pick the value to use for symbols defined in the PLT.
2243   Symbol_value<64> symval;
2244   if (gsym != NULL
2245       && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
2246                               || r_type == elfcpp::R_X86_64_PC32
2247                               || r_type == elfcpp::R_X86_64_PC16
2248                               || r_type == elfcpp::R_X86_64_PC8))
2249     {
2250       symval.set_output_value(target->plt_section()->address()
2251                               + gsym->plt_offset());
2252       psymval = &symval;
2253     }
2254   else if (gsym == NULL && psymval->is_ifunc_symbol())
2255     {
2256       unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2257       if (object->local_has_plt_offset(r_sym))
2258         {
2259           symval.set_output_value(target->plt_section()->address()
2260                                   + object->local_plt_offset(r_sym));
2261           psymval = &symval;
2262         }
2263     }
2264
2265   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2266
2267   // Get the GOT offset if needed.
2268   // The GOT pointer points to the end of the GOT section.
2269   // We need to subtract the size of the GOT section to get
2270   // the actual offset to use in the relocation.
2271   bool have_got_offset = false;
2272   unsigned int got_offset = 0;
2273   switch (r_type)
2274     {
2275     case elfcpp::R_X86_64_GOT32:
2276     case elfcpp::R_X86_64_GOT64:
2277     case elfcpp::R_X86_64_GOTPLT64:
2278     case elfcpp::R_X86_64_GOTPCREL:
2279     case elfcpp::R_X86_64_GOTPCREL64:
2280       if (gsym != NULL)
2281         {
2282           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2283           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
2284         }
2285       else
2286         {
2287           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2288           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2289           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2290                         - target->got_size());
2291         }
2292       have_got_offset = true;
2293       break;
2294
2295     default:
2296       break;
2297     }
2298
2299   switch (r_type)
2300     {
2301     case elfcpp::R_X86_64_NONE:
2302     case elfcpp::R_X86_64_GNU_VTINHERIT:
2303     case elfcpp::R_X86_64_GNU_VTENTRY:
2304       break;
2305
2306     case elfcpp::R_X86_64_64:
2307       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
2308       break;
2309
2310     case elfcpp::R_X86_64_PC64:
2311       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
2312                                               address);
2313       break;
2314
2315     case elfcpp::R_X86_64_32:
2316       // FIXME: we need to verify that value + addend fits into 32 bits:
2317       //    uint64_t x = value + addend;
2318       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2319       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2320       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2321       break;
2322
2323     case elfcpp::R_X86_64_32S:
2324       // FIXME: we need to verify that value + addend fits into 32 bits:
2325       //    int64_t x = value + addend;   // note this quantity is signed!
2326       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
2327       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2328       break;
2329
2330     case elfcpp::R_X86_64_PC32:
2331       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2332                                               address);
2333       break;
2334
2335     case elfcpp::R_X86_64_16:
2336       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2337       break;
2338
2339     case elfcpp::R_X86_64_PC16:
2340       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2341                                               address);
2342       break;
2343
2344     case elfcpp::R_X86_64_8:
2345       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2346       break;
2347
2348     case elfcpp::R_X86_64_PC8:
2349       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2350                                              address);
2351       break;
2352
2353     case elfcpp::R_X86_64_PLT32:
2354       gold_assert(gsym == NULL
2355                   || gsym->has_plt_offset()
2356                   || gsym->final_value_is_known()
2357                   || (gsym->is_defined()
2358                       && !gsym->is_from_dynobj()
2359                       && !gsym->is_preemptible()));
2360       // Note: while this code looks the same as for R_X86_64_PC32, it
2361       // behaves differently because psymval was set to point to
2362       // the PLT entry, rather than the symbol, in Scan::global().
2363       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2364                                               address);
2365       break;
2366
2367     case elfcpp::R_X86_64_PLTOFF64:
2368       {
2369         gold_assert(gsym);
2370         gold_assert(gsym->has_plt_offset()
2371                     || gsym->final_value_is_known());
2372         elfcpp::Elf_types<64>::Elf_Addr got_address;
2373         got_address = target->got_section(NULL, NULL)->address();
2374         Relocate_functions<64, false>::rela64(view, object, psymval,
2375                                               addend - got_address);
2376       }
2377
2378     case elfcpp::R_X86_64_GOT32:
2379       gold_assert(have_got_offset);
2380       Relocate_functions<64, false>::rela32(view, got_offset, addend);
2381       break;
2382
2383     case elfcpp::R_X86_64_GOTPC32:
2384       {
2385         gold_assert(gsym);
2386         elfcpp::Elf_types<64>::Elf_Addr value;
2387         value = target->got_plt_section()->address();
2388         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2389       }
2390       break;
2391
2392     case elfcpp::R_X86_64_GOT64:
2393       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2394       // Since we always add a PLT entry, this is equivalent.
2395     case elfcpp::R_X86_64_GOTPLT64:
2396       gold_assert(have_got_offset);
2397       Relocate_functions<64, false>::rela64(view, got_offset, addend);
2398       break;
2399
2400     case elfcpp::R_X86_64_GOTPC64:
2401       {
2402         gold_assert(gsym);
2403         elfcpp::Elf_types<64>::Elf_Addr value;
2404         value = target->got_plt_section()->address();
2405         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2406       }
2407       break;
2408
2409     case elfcpp::R_X86_64_GOTOFF64:
2410       {
2411         elfcpp::Elf_types<64>::Elf_Addr value;
2412         value = (psymval->value(object, 0)
2413                  - target->got_plt_section()->address());
2414         Relocate_functions<64, false>::rela64(view, value, addend);
2415       }
2416       break;
2417
2418     case elfcpp::R_X86_64_GOTPCREL:
2419       {
2420         gold_assert(have_got_offset);
2421         elfcpp::Elf_types<64>::Elf_Addr value;
2422         value = target->got_plt_section()->address() + got_offset;
2423         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2424       }
2425       break;
2426
2427     case elfcpp::R_X86_64_GOTPCREL64:
2428       {
2429         gold_assert(have_got_offset);
2430         elfcpp::Elf_types<64>::Elf_Addr value;
2431         value = target->got_plt_section()->address() + got_offset;
2432         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2433       }
2434       break;
2435
2436     case elfcpp::R_X86_64_COPY:
2437     case elfcpp::R_X86_64_GLOB_DAT:
2438     case elfcpp::R_X86_64_JUMP_SLOT:
2439     case elfcpp::R_X86_64_RELATIVE:
2440     case elfcpp::R_X86_64_IRELATIVE:
2441       // These are outstanding tls relocs, which are unexpected when linking
2442     case elfcpp::R_X86_64_TPOFF64:
2443     case elfcpp::R_X86_64_DTPMOD64:
2444     case elfcpp::R_X86_64_TLSDESC:
2445       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2446                              _("unexpected reloc %u in object file"),
2447                              r_type);
2448       break;
2449
2450       // These are initial tls relocs, which are expected when linking
2451     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2452     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2453     case elfcpp::R_X86_64_TLSDESC_CALL:
2454     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2455     case elfcpp::R_X86_64_DTPOFF32:
2456     case elfcpp::R_X86_64_DTPOFF64:
2457     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2458     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2459       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
2460                          view, address, view_size);
2461       break;
2462
2463     case elfcpp::R_X86_64_SIZE32:
2464     case elfcpp::R_X86_64_SIZE64:
2465     default:
2466       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2467                              _("unsupported reloc %u"),
2468                              r_type);
2469       break;
2470     }
2471
2472   return true;
2473 }
2474
2475 // Perform a TLS relocation.
2476
2477 inline void
2478 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
2479                                       Target_x86_64* target,
2480                                       size_t relnum,
2481                                       const elfcpp::Rela<64, false>& rela,
2482                                       unsigned int r_type,
2483                                       const Sized_symbol<64>* gsym,
2484                                       const Symbol_value<64>* psymval,
2485                                       unsigned char* view,
2486                                       elfcpp::Elf_types<64>::Elf_Addr address,
2487                                       section_size_type view_size)
2488 {
2489   Output_segment* tls_segment = relinfo->layout->tls_segment();
2490
2491   const Sized_relobj<64, false>* object = relinfo->object;
2492   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2493   elfcpp::Shdr<64, false> data_shdr(relinfo->data_shdr);
2494   bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
2495
2496   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
2497
2498   const bool is_final = (gsym == NULL
2499                          ? !parameters->options().shared()
2500                          : gsym->final_value_is_known());
2501   tls::Tls_optimization optimized_type
2502       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
2503   switch (r_type)
2504     {
2505     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2506       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
2507         {
2508           // If this code sequence is used in a non-executable section,
2509           // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
2510           // on the assumption that it's being used by itself in a debug
2511           // section.  Therefore, in the unlikely event that the code
2512           // sequence appears in a non-executable section, we simply
2513           // leave it unoptimized.
2514           optimized_type = tls::TLSOPT_NONE;
2515         }
2516       if (optimized_type == tls::TLSOPT_TO_LE)
2517         {
2518           gold_assert(tls_segment != NULL);
2519           this->tls_gd_to_le(relinfo, relnum, tls_segment,
2520                              rela, r_type, value, view,
2521                              view_size);
2522           break;
2523         }
2524       else
2525         {
2526           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2527                                    ? GOT_TYPE_TLS_OFFSET
2528                                    : GOT_TYPE_TLS_PAIR);
2529           unsigned int got_offset;
2530           if (gsym != NULL)
2531             {
2532               gold_assert(gsym->has_got_offset(got_type));
2533               got_offset = gsym->got_offset(got_type) - target->got_size();
2534             }
2535           else
2536             {
2537               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2538               gold_assert(object->local_has_got_offset(r_sym, got_type));
2539               got_offset = (object->local_got_offset(r_sym, got_type)
2540                             - target->got_size());
2541             }
2542           if (optimized_type == tls::TLSOPT_TO_IE)
2543             {
2544               gold_assert(tls_segment != NULL);
2545               value = target->got_plt_section()->address() + got_offset;
2546               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2547                                  value, view, address, view_size);
2548               break;
2549             }
2550           else if (optimized_type == tls::TLSOPT_NONE)
2551             {
2552               // Relocate the field with the offset of the pair of GOT
2553               // entries.
2554               value = target->got_plt_section()->address() + got_offset;
2555               Relocate_functions<64, false>::pcrela32(view, value, addend,
2556                                                       address);
2557               break;
2558             }
2559         }
2560       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2561                              _("unsupported reloc %u"), r_type);
2562       break;
2563
2564     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2565     case elfcpp::R_X86_64_TLSDESC_CALL:
2566       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
2567         {
2568           // See above comment for R_X86_64_TLSGD.
2569           optimized_type = tls::TLSOPT_NONE;
2570         }
2571       if (optimized_type == tls::TLSOPT_TO_LE)
2572         {
2573           gold_assert(tls_segment != NULL);
2574           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2575                                   rela, r_type, value, view,
2576                                   view_size);
2577           break;
2578         }
2579       else
2580         {
2581           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2582                                    ? GOT_TYPE_TLS_OFFSET
2583                                    : GOT_TYPE_TLS_DESC);
2584           unsigned int got_offset = 0;
2585           if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
2586               && optimized_type == tls::TLSOPT_NONE)
2587             {
2588               // We created GOT entries in the .got.tlsdesc portion of
2589               // the .got.plt section, but the offset stored in the
2590               // symbol is the offset within .got.tlsdesc.
2591               got_offset = (target->got_size()
2592                             + target->got_plt_section()->data_size());
2593             }
2594           if (gsym != NULL)
2595             {
2596               gold_assert(gsym->has_got_offset(got_type));
2597               got_offset += gsym->got_offset(got_type) - target->got_size();
2598             }
2599           else
2600             {
2601               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2602               gold_assert(object->local_has_got_offset(r_sym, got_type));
2603               got_offset += (object->local_got_offset(r_sym, got_type)
2604                              - target->got_size());
2605             }
2606           if (optimized_type == tls::TLSOPT_TO_IE)
2607             {
2608               gold_assert(tls_segment != NULL);
2609               value = target->got_plt_section()->address() + got_offset;
2610               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2611                                       rela, r_type, value, view, address,
2612                                       view_size);
2613               break;
2614             }
2615           else if (optimized_type == tls::TLSOPT_NONE)
2616             {
2617               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2618                 {
2619                   // Relocate the field with the offset of the pair of GOT
2620                   // entries.
2621                   value = target->got_plt_section()->address() + got_offset;
2622                   Relocate_functions<64, false>::pcrela32(view, value, addend,
2623                                                           address);
2624                 }
2625               break;
2626             }
2627         }
2628       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2629                              _("unsupported reloc %u"), r_type);
2630       break;
2631
2632     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2633       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
2634         {
2635           // See above comment for R_X86_64_TLSGD.
2636           optimized_type = tls::TLSOPT_NONE;
2637         }
2638       if (optimized_type == tls::TLSOPT_TO_LE)
2639         {
2640           gold_assert(tls_segment != NULL);
2641           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2642                              value, view, view_size);
2643           break;
2644         }
2645       else if (optimized_type == tls::TLSOPT_NONE)
2646         {
2647           // Relocate the field with the offset of the GOT entry for
2648           // the module index.
2649           unsigned int got_offset;
2650           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2651                         - target->got_size());
2652           value = target->got_plt_section()->address() + got_offset;
2653           Relocate_functions<64, false>::pcrela32(view, value, addend,
2654                                                   address);
2655           break;
2656         }
2657       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2658                              _("unsupported reloc %u"), r_type);
2659       break;
2660
2661     case elfcpp::R_X86_64_DTPOFF32:
2662       // This relocation type is used in debugging information.
2663       // In that case we need to not optimize the value.  If the
2664       // section is not executable, then we assume we should not
2665       // optimize this reloc.  See comments above for R_X86_64_TLSGD,
2666       // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
2667       // R_X86_64_TLSLD.
2668       if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
2669         {
2670           gold_assert(tls_segment != NULL);
2671           value -= tls_segment->memsz();
2672         }
2673       Relocate_functions<64, false>::rela32(view, value, addend);
2674       break;
2675
2676     case elfcpp::R_X86_64_DTPOFF64:
2677       // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
2678       if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
2679         {
2680           gold_assert(tls_segment != NULL);
2681           value -= tls_segment->memsz();
2682         }
2683       Relocate_functions<64, false>::rela64(view, value, addend);
2684       break;
2685
2686     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2687       if (optimized_type == tls::TLSOPT_TO_LE)
2688         {
2689           gold_assert(tls_segment != NULL);
2690           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2691                                                 rela, r_type, value, view,
2692                                                 view_size);
2693           break;
2694         }
2695       else if (optimized_type == tls::TLSOPT_NONE)
2696         {
2697           // Relocate the field with the offset of the GOT entry for
2698           // the tp-relative offset of the symbol.
2699           unsigned int got_offset;
2700           if (gsym != NULL)
2701             {
2702               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2703               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2704                             - target->got_size());
2705             }
2706           else
2707             {
2708               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2709               gold_assert(object->local_has_got_offset(r_sym,
2710                                                        GOT_TYPE_TLS_OFFSET));
2711               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2712                             - target->got_size());
2713             }
2714           value = target->got_plt_section()->address() + got_offset;
2715           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2716           break;
2717         }
2718       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2719                              _("unsupported reloc type %u"),
2720                              r_type);
2721       break;
2722
2723     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2724       value -= tls_segment->memsz();
2725       Relocate_functions<64, false>::rela32(view, value, addend);
2726       break;
2727     }
2728 }
2729
2730 // Do a relocation in which we convert a TLS General-Dynamic to an
2731 // Initial-Exec.
2732
2733 inline void
2734 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2735                                       size_t relnum,
2736                                       Output_segment*,
2737                                       const elfcpp::Rela<64, false>& rela,
2738                                       unsigned int,
2739                                       elfcpp::Elf_types<64>::Elf_Addr value,
2740                                       unsigned char* view,
2741                                       elfcpp::Elf_types<64>::Elf_Addr address,
2742                                       section_size_type view_size)
2743 {
2744   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2745   // .word 0x6666; rex64; call __tls_get_addr
2746   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2747
2748   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2749   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2750
2751   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2752                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2753   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2754                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2755
2756   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2757
2758   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2759   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2760
2761   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2762   // We can skip it.
2763   this->skip_call_tls_get_addr_ = true;
2764 }
2765
2766 // Do a relocation in which we convert a TLS General-Dynamic to a
2767 // Local-Exec.
2768
2769 inline void
2770 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2771                                       size_t relnum,
2772                                       Output_segment* tls_segment,
2773                                       const elfcpp::Rela<64, false>& rela,
2774                                       unsigned int,
2775                                       elfcpp::Elf_types<64>::Elf_Addr value,
2776                                       unsigned char* view,
2777                                       section_size_type view_size)
2778 {
2779   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2780   // .word 0x6666; rex64; call __tls_get_addr
2781   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2782
2783   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2784   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2785
2786   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2787                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2788   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2789                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2790
2791   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2792
2793   value -= tls_segment->memsz();
2794   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2795
2796   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2797   // We can skip it.
2798   this->skip_call_tls_get_addr_ = true;
2799 }
2800
2801 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2802
2803 inline void
2804 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2805     const Relocate_info<64, false>* relinfo,
2806     size_t relnum,
2807     Output_segment*,
2808     const elfcpp::Rela<64, false>& rela,
2809     unsigned int r_type,
2810     elfcpp::Elf_types<64>::Elf_Addr value,
2811     unsigned char* view,
2812     elfcpp::Elf_types<64>::Elf_Addr address,
2813     section_size_type view_size)
2814 {
2815   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2816     {
2817       // leaq foo@tlsdesc(%rip), %rax
2818       // ==> movq foo@gottpoff(%rip), %rax
2819       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2820       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2821       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2822                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2823       view[-2] = 0x8b;
2824       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2825       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2826     }
2827   else
2828     {
2829       // call *foo@tlscall(%rax)
2830       // ==> nop; nop
2831       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2832       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2833       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2834                      view[0] == 0xff && view[1] == 0x10);
2835       view[0] = 0x66;
2836       view[1] = 0x90;
2837     }
2838 }
2839
2840 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2841
2842 inline void
2843 Target_x86_64::Relocate::tls_desc_gd_to_le(
2844     const Relocate_info<64, false>* relinfo,
2845     size_t relnum,
2846     Output_segment* tls_segment,
2847     const elfcpp::Rela<64, false>& rela,
2848     unsigned int r_type,
2849     elfcpp::Elf_types<64>::Elf_Addr value,
2850     unsigned char* view,
2851     section_size_type view_size)
2852 {
2853   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2854     {
2855       // leaq foo@tlsdesc(%rip), %rax
2856       // ==> movq foo@tpoff, %rax
2857       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2858       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2859       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2860                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2861       view[-2] = 0xc7;
2862       view[-1] = 0xc0;
2863       value -= tls_segment->memsz();
2864       Relocate_functions<64, false>::rela32(view, value, 0);
2865     }
2866   else
2867     {
2868       // call *foo@tlscall(%rax)
2869       // ==> nop; nop
2870       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2871       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2872       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2873                      view[0] == 0xff && view[1] == 0x10);
2874       view[0] = 0x66;
2875       view[1] = 0x90;
2876     }
2877 }
2878
2879 inline void
2880 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2881                                       size_t relnum,
2882                                       Output_segment*,
2883                                       const elfcpp::Rela<64, false>& rela,
2884                                       unsigned int,
2885                                       elfcpp::Elf_types<64>::Elf_Addr,
2886                                       unsigned char* view,
2887                                       section_size_type view_size)
2888 {
2889   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2890   // ... leq foo@dtpoff(%rax),%reg
2891   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2892
2893   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2894   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2895
2896   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2897                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2898
2899   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2900
2901   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2902
2903   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2904   // We can skip it.
2905   this->skip_call_tls_get_addr_ = true;
2906 }
2907
2908 // Do a relocation in which we convert a TLS Initial-Exec to a
2909 // Local-Exec.
2910
2911 inline void
2912 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2913                                       size_t relnum,
2914                                       Output_segment* tls_segment,
2915                                       const elfcpp::Rela<64, false>& rela,
2916                                       unsigned int,
2917                                       elfcpp::Elf_types<64>::Elf_Addr value,
2918                                       unsigned char* view,
2919                                       section_size_type view_size)
2920 {
2921   // We need to examine the opcodes to figure out which instruction we
2922   // are looking at.
2923
2924   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2925   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2926
2927   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2928   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2929
2930   unsigned char op1 = view[-3];
2931   unsigned char op2 = view[-2];
2932   unsigned char op3 = view[-1];
2933   unsigned char reg = op3 >> 3;
2934
2935   if (op2 == 0x8b)
2936     {
2937       // movq
2938       if (op1 == 0x4c)
2939         view[-3] = 0x49;
2940       view[-2] = 0xc7;
2941       view[-1] = 0xc0 | reg;
2942     }
2943   else if (reg == 4)
2944     {
2945       // Special handling for %rsp.
2946       if (op1 == 0x4c)
2947         view[-3] = 0x49;
2948       view[-2] = 0x81;
2949       view[-1] = 0xc0 | reg;
2950     }
2951   else
2952     {
2953       // addq
2954       if (op1 == 0x4c)
2955         view[-3] = 0x4d;
2956       view[-2] = 0x8d;
2957       view[-1] = 0x80 | reg | (reg << 3);
2958     }
2959
2960   value -= tls_segment->memsz();
2961   Relocate_functions<64, false>::rela32(view, value, 0);
2962 }
2963
2964 // Relocate section data.
2965
2966 void
2967 Target_x86_64::relocate_section(
2968     const Relocate_info<64, false>* relinfo,
2969     unsigned int sh_type,
2970     const unsigned char* prelocs,
2971     size_t reloc_count,
2972     Output_section* output_section,
2973     bool needs_special_offset_handling,
2974     unsigned char* view,
2975     elfcpp::Elf_types<64>::Elf_Addr address,
2976     section_size_type view_size,
2977     const Reloc_symbol_changes* reloc_symbol_changes)
2978 {
2979   gold_assert(sh_type == elfcpp::SHT_RELA);
2980
2981   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2982                          Target_x86_64::Relocate>(
2983     relinfo,
2984     this,
2985     prelocs,
2986     reloc_count,
2987     output_section,
2988     needs_special_offset_handling,
2989     view,
2990     address,
2991     view_size,
2992     reloc_symbol_changes);
2993 }
2994
2995 // Return the size of a relocation while scanning during a relocatable
2996 // link.
2997
2998 unsigned int
2999 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
3000     unsigned int r_type,
3001     Relobj* object)
3002 {
3003   switch (r_type)
3004     {
3005     case elfcpp::R_X86_64_NONE:
3006     case elfcpp::R_X86_64_GNU_VTINHERIT:
3007     case elfcpp::R_X86_64_GNU_VTENTRY:
3008     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
3009     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
3010     case elfcpp::R_X86_64_TLSDESC_CALL:
3011     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
3012     case elfcpp::R_X86_64_DTPOFF32:
3013     case elfcpp::R_X86_64_DTPOFF64:
3014     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
3015     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
3016       return 0;
3017
3018     case elfcpp::R_X86_64_64:
3019     case elfcpp::R_X86_64_PC64:
3020     case elfcpp::R_X86_64_GOTOFF64:
3021     case elfcpp::R_X86_64_GOTPC64:
3022     case elfcpp::R_X86_64_PLTOFF64:
3023     case elfcpp::R_X86_64_GOT64:
3024     case elfcpp::R_X86_64_GOTPCREL64:
3025     case elfcpp::R_X86_64_GOTPCREL:
3026     case elfcpp::R_X86_64_GOTPLT64:
3027       return 8;
3028
3029     case elfcpp::R_X86_64_32:
3030     case elfcpp::R_X86_64_32S:
3031     case elfcpp::R_X86_64_PC32:
3032     case elfcpp::R_X86_64_PLT32:
3033     case elfcpp::R_X86_64_GOTPC32:
3034     case elfcpp::R_X86_64_GOT32:
3035       return 4;
3036
3037     case elfcpp::R_X86_64_16:
3038     case elfcpp::R_X86_64_PC16:
3039       return 2;
3040
3041     case elfcpp::R_X86_64_8:
3042     case elfcpp::R_X86_64_PC8:
3043       return 1;
3044
3045     case elfcpp::R_X86_64_COPY:
3046     case elfcpp::R_X86_64_GLOB_DAT:
3047     case elfcpp::R_X86_64_JUMP_SLOT:
3048     case elfcpp::R_X86_64_RELATIVE:
3049     case elfcpp::R_X86_64_IRELATIVE:
3050       // These are outstanding tls relocs, which are unexpected when linking
3051     case elfcpp::R_X86_64_TPOFF64:
3052     case elfcpp::R_X86_64_DTPMOD64:
3053     case elfcpp::R_X86_64_TLSDESC:
3054       object->error(_("unexpected reloc %u in object file"), r_type);
3055       return 0;
3056
3057     case elfcpp::R_X86_64_SIZE32:
3058     case elfcpp::R_X86_64_SIZE64:
3059     default:
3060       object->error(_("unsupported reloc %u against local symbol"), r_type);
3061       return 0;
3062     }
3063 }
3064
3065 // Scan the relocs during a relocatable link.
3066
3067 void
3068 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
3069                                        Layout* layout,
3070                                        Sized_relobj<64, false>* object,
3071                                        unsigned int data_shndx,
3072                                        unsigned int sh_type,
3073                                        const unsigned char* prelocs,
3074                                        size_t reloc_count,
3075                                        Output_section* output_section,
3076                                        bool needs_special_offset_handling,
3077                                        size_t local_symbol_count,
3078                                        const unsigned char* plocal_symbols,
3079                                        Relocatable_relocs* rr)
3080 {
3081   gold_assert(sh_type == elfcpp::SHT_RELA);
3082
3083   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
3084     Relocatable_size_for_reloc> Scan_relocatable_relocs;
3085
3086   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
3087       Scan_relocatable_relocs>(
3088     symtab,
3089     layout,
3090     object,
3091     data_shndx,
3092     prelocs,
3093     reloc_count,
3094     output_section,
3095     needs_special_offset_handling,
3096     local_symbol_count,
3097     plocal_symbols,
3098     rr);
3099 }
3100
3101 // Relocate a section during a relocatable link.
3102
3103 void
3104 Target_x86_64::relocate_for_relocatable(
3105     const Relocate_info<64, false>* relinfo,
3106     unsigned int sh_type,
3107     const unsigned char* prelocs,
3108     size_t reloc_count,
3109     Output_section* output_section,
3110     off_t offset_in_output_section,
3111     const Relocatable_relocs* rr,
3112     unsigned char* view,
3113     elfcpp::Elf_types<64>::Elf_Addr view_address,
3114     section_size_type view_size,
3115     unsigned char* reloc_view,
3116     section_size_type reloc_view_size)
3117 {
3118   gold_assert(sh_type == elfcpp::SHT_RELA);
3119
3120   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
3121     relinfo,
3122     prelocs,
3123     reloc_count,
3124     output_section,
3125     offset_in_output_section,
3126     rr,
3127     view,
3128     view_address,
3129     view_size,
3130     reloc_view,
3131     reloc_view_size);
3132 }
3133
3134 // Return the value to use for a dynamic which requires special
3135 // treatment.  This is how we support equality comparisons of function
3136 // pointers across shared library boundaries, as described in the
3137 // processor specific ABI supplement.
3138
3139 uint64_t
3140 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
3141 {
3142   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3143   return this->plt_section()->address() + gsym->plt_offset();
3144 }
3145
3146 // Return a string used to fill a code section with nops to take up
3147 // the specified length.
3148
3149 std::string
3150 Target_x86_64::do_code_fill(section_size_type length) const
3151 {
3152   if (length >= 16)
3153     {
3154       // Build a jmpq instruction to skip over the bytes.
3155       unsigned char jmp[5];
3156       jmp[0] = 0xe9;
3157       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3158       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3159               + std::string(length - 5, '\0'));
3160     }
3161
3162   // Nop sequences of various lengths.
3163   const char nop1[1] = { 0x90 };                   // nop
3164   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
3165   const char nop3[3] = { 0x0f, 0x1f, 0x00 };       // nop (%rax)
3166   const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00};  // nop 0(%rax)
3167   const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00,   // nop 0(%rax,%rax,1)
3168                          0x00 };
3169   const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44,   // nopw 0(%rax,%rax,1)
3170                          0x00, 0x00 };
3171   const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00,   // nopl 0L(%rax)
3172                          0x00, 0x00, 0x00 };
3173   const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00,   // nopl 0L(%rax,%rax,1)
3174                          0x00, 0x00, 0x00, 0x00 };
3175   const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84,   // nopw 0L(%rax,%rax,1)
3176                          0x00, 0x00, 0x00, 0x00,
3177                          0x00 };
3178   const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
3179                            0x84, 0x00, 0x00, 0x00,
3180                            0x00, 0x00 };
3181   const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
3182                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3183                            0x00, 0x00, 0x00 };
3184   const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
3185                            0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
3186                            0x00, 0x00, 0x00, 0x00 };
3187   const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3188                            0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
3189                            0x00, 0x00, 0x00, 0x00,
3190                            0x00 };
3191   const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3192                            0x66, 0x2e, 0x0f, 0x1f, // data16
3193                            0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3194                            0x00, 0x00 };
3195   const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3196                            0x66, 0x66, 0x2e, 0x0f, // data16; data16
3197                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3198                            0x00, 0x00, 0x00 };
3199
3200   const char* nops[16] = {
3201     NULL,
3202     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3203     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3204   };
3205
3206   return std::string(nops[length], length);
3207 }
3208
3209 // Return the addend to use for a target specific relocation.  The
3210 // only target specific relocation is R_X86_64_TLSDESC for a local
3211 // symbol.  We want to set the addend is the offset of the local
3212 // symbol in the TLS segment.
3213
3214 uint64_t
3215 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
3216                                uint64_t) const
3217 {
3218   gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
3219   uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
3220   gold_assert(intarg < this->tlsdesc_reloc_info_.size());
3221   const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
3222   const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
3223   gold_assert(psymval->is_tls_symbol());
3224   // The value of a TLS symbol is the offset in the TLS segment.
3225   return psymval->value(ti.object, 0);
3226 }
3227
3228 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3229 // compiled with -fstack-split.  The function calls non-stack-split
3230 // code.  We have to change the function so that it always ensures
3231 // that it has enough stack space to run some random function.
3232
3233 void
3234 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
3235                                   section_offset_type fnoffset,
3236                                   section_size_type fnsize,
3237                                   unsigned char* view,
3238                                   section_size_type view_size,
3239                                   std::string* from,
3240                                   std::string* to) const
3241 {
3242   // The function starts with a comparison of the stack pointer and a
3243   // field in the TCB.  This is followed by a jump.
3244
3245   // cmp %fs:NN,%rsp
3246   if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
3247       && fnsize > 9)
3248     {
3249       // We will call __morestack if the carry flag is set after this
3250       // comparison.  We turn the comparison into an stc instruction
3251       // and some nops.
3252       view[fnoffset] = '\xf9';
3253       this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
3254     }
3255   // lea NN(%rsp),%r10
3256   // lea NN(%rsp),%r11
3257   else if ((this->match_view(view, view_size, fnoffset,
3258                              "\x4c\x8d\x94\x24", 4)
3259             || this->match_view(view, view_size, fnoffset,
3260                                 "\x4c\x8d\x9c\x24", 4))
3261            && fnsize > 8)
3262     {
3263       // This is loading an offset from the stack pointer for a
3264       // comparison.  The offset is negative, so we decrease the
3265       // offset by the amount of space we need for the stack.  This
3266       // means we will avoid calling __morestack if there happens to
3267       // be plenty of space on the stack already.
3268       unsigned char* pval = view + fnoffset + 4;
3269       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3270       val -= parameters->options().split_stack_adjust_size();
3271       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3272     }
3273   else
3274     {
3275       if (!object->has_no_split_stack())
3276         object->error(_("failed to match split-stack sequence at "
3277                         "section %u offset %0zx"),
3278                       shndx, static_cast<size_t>(fnoffset));
3279       return;
3280     }
3281
3282   // We have to change the function so that it calls
3283   // __morestack_non_split instead of __morestack.  The former will
3284   // allocate additional stack space.
3285   *from = "__morestack";
3286   *to = "__morestack_non_split";
3287 }
3288
3289 // The selector for x86_64 object files.
3290
3291 class Target_selector_x86_64 : public Target_selector_freebsd
3292 {
3293 public:
3294   Target_selector_x86_64()
3295     : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
3296                               "elf64-x86-64-freebsd")
3297   { }
3298
3299   Target*
3300   do_instantiate_target()
3301   { return new Target_x86_64(); }
3302
3303 };
3304
3305 Target_selector_x86_64 target_selector_x86_64;
3306
3307 } // End anonymous namespace.