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   // Hook for a new output section.
 193   void
 194   do_new_output_section(Output_section*) const;
 195
 196   // Scan the relocations to look for symbol adjustments.
 197   void
 198   gc_process_relocs(Symbol_table* symtab,
 199                     Layout* layout,
 200                     Sized_relobj<64, false>* object,
 201                     unsigned int data_shndx,
 202                     unsigned int sh_type,
 203                     const unsigned char* prelocs,
 204                     size_t reloc_count,
 205                     Output_section* output_section,
 206                     bool needs_special_offset_handling,
 207                     size_t local_symbol_count,
 208                     const unsigned char* plocal_symbols);
 209
 210   // Scan the relocations to look for symbol adjustments.
 211   void
 212   scan_relocs(Symbol_table* symtab,
 213               Layout* layout,
 214               Sized_relobj<64, false>* object,
 215               unsigned int data_shndx,
 216               unsigned int sh_type,
 217               const unsigned char* prelocs,
 218               size_t reloc_count,
 219               Output_section* output_section,
 220               bool needs_special_offset_handling,
 221               size_t local_symbol_count,
 222               const unsigned char* plocal_symbols);
 223
 224   // Finalize the sections.
 225   void
 226   do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
 227
 228   // Return the value to use for a dynamic which requires special
 229   // treatment.
 230   uint64_t
 231   do_dynsym_value(const Symbol*) const;
 232
 233   // Relocate a section.
 234   void
 235   relocate_section(const Relocate_info<64, false>*,
 236                    unsigned int sh_type,
 237                    const unsigned char* prelocs,
 238                    size_t reloc_count,
 239                    Output_section* output_section,
 240                    bool needs_special_offset_handling,
 241                    unsigned char* view,
 242                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 243                    section_size_type view_size,
 244                    const Reloc_symbol_changes*);
 245
 246   // Scan the relocs during a relocatable link.
 247   void
 248   scan_relocatable_relocs(Symbol_table* symtab,
 249                           Layout* layout,
 250                           Sized_relobj<64, false>* object,
 251                           unsigned int data_shndx,
 252                           unsigned int sh_type,
 253                           const unsigned char* prelocs,
 254                           size_t reloc_count,
 255                           Output_section* output_section,
 256                           bool needs_special_offset_handling,
 257                           size_t local_symbol_count,
 258                           const unsigned char* plocal_symbols,
 259                           Relocatable_relocs*);
 260
 261   // Relocate a section during a relocatable link.
 262   void
 263   relocate_for_relocatable(const Relocate_info<64, false>*,
 264                            unsigned int sh_type,
 265                            const unsigned char* prelocs,
 266                            size_t reloc_count,
 267                            Output_section* output_section,
 268                            off_t offset_in_output_section,
 269                            const Relocatable_relocs*,
 270                            unsigned char* view,
 271                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 272                            section_size_type view_size,
 273                            unsigned char* reloc_view,
 274                            section_size_type reloc_view_size);
 275
 276   // Return a string used to fill a code section with nops.
 277   std::string
 278   do_code_fill(section_size_type length) const;
 279
 280   // Return whether SYM is defined by the ABI.
 281   bool
 282   do_is_defined_by_abi(const Symbol* sym) const
 283   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 284
 285   // Return the symbol index to use for a target specific relocation.
 286   // The only target specific relocation is R_X86_64_TLSDESC for a
 287   // local symbol, which is an absolute reloc.
 288   unsigned int
 289   do_reloc_symbol_index(void*, unsigned int r_type) const
 290   {
 291     gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
 292     return 0;
 293   }
 294
 295   // Return the addend to use for a target specific relocation.
 296   uint64_t
 297   do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
 298
 299   // Return the PLT section.
 300   Output_data*
 301   do_plt_section_for_global(const Symbol*) const
 302   { return this->plt_section(); }
 303
 304   Output_data*
 305   do_plt_section_for_local(const Relobj*, unsigned int) const
 306   { return this->plt_section(); }
 307
 308   // Adjust -fstack-split code which calls non-stack-split code.
 309   void
 310   do_calls_non_split(Relobj* object, unsigned int shndx,
 311                      section_offset_type fnoffset, section_size_type fnsize,
 312                      unsigned char* view, section_size_type view_size,
 313                      std::string* from, std::string* to) const;
 314
 315   // Return the size of the GOT section.
 316   section_size_type
 317   got_size() const
 318   {
 319     gold_assert(this->got_ != NULL);
 320     return this->got_->data_size();
 321   }
 322
 323   // Return the number of entries in the GOT.
 324   unsigned int
 325   got_entry_count() const
 326   {
 327     if (this->got_ == NULL)
 328       return 0;
 329     return this->got_size() / 8;
 330   }
 331
 332   // Return the number of entries in the PLT.
 333   unsigned int
 334   plt_entry_count() const;
 335
 336   // Return the offset of the first non-reserved PLT entry.
 337   unsigned int
 338   first_plt_entry_offset() const;
 339
 340   // Return the size of each PLT entry.
 341   unsigned int
 342   plt_entry_size() const;
 343
 344   // Add a new reloc argument, returning the index in the vector.
 345   size_t
 346   add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym)
 347   {
 348     this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
 349     return this->tlsdesc_reloc_info_.size() - 1;
 350   }
 351
 352  private:
 353   // The class which scans relocations.
 354   class Scan
 355   {
 356   public:
 357     Scan()
 358       : issued_non_pic_error_(false)
 359     { }
 360
 361     inline void
 362     local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 363           Sized_relobj<64, false>* object,
 364           unsigned int data_shndx,
 365           Output_section* output_section,
 366           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 367           const elfcpp::Sym<64, false>& lsym);
 368
 369     inline void
 370     global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 371            Sized_relobj<64, false>* object,
 372            unsigned int data_shndx,
 373            Output_section* output_section,
 374            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 375            Symbol* gsym);
 376
 377     inline bool
 378     local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 379                                         Target_x86_64* target,
 380                                         Sized_relobj<64, false>* object,
 381                                         unsigned int data_shndx,
 382                                         Output_section* output_section,
 383                                         const elfcpp::Rela<64, false>& reloc,
 384                                         unsigned int r_type,
 385                                         const elfcpp::Sym<64, false>& lsym);
 386
 387     inline bool
 388     global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 389                                          Target_x86_64* target,
 390                                          Sized_relobj<64, false>* object,
 391                                          unsigned int data_shndx,
 392                                          Output_section* output_section,
 393                                          const elfcpp::Rela<64, false>& reloc,
 394                                          unsigned int r_type,
 395                                          Symbol* gsym);
 396
 397   private:
 398     static void
 399     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 400
 401     static void
 402     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 403                              Symbol*);
 404
 405     void
 406     check_non_pic(Relobj*, unsigned int r_type);
 407
 408     inline bool
 409     possible_function_pointer_reloc(unsigned int r_type);
 410
 411     bool
 412     reloc_needs_plt_for_ifunc(Sized_relobj<64, false>*, unsigned int r_type);
 413
 414     // Whether we have issued an error about a non-PIC compilation.
 415     bool issued_non_pic_error_;
 416   };
 417
 418   // The class which implements relocation.
 419   class Relocate
 420   {
 421    public:
 422     Relocate()
 423       : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
 424     { }
 425
 426     ~Relocate()
 427     {
 428       if (this->skip_call_tls_get_addr_)
 429         {
 430           // FIXME: This needs to specify the location somehow.
 431           gold_error(_("missing expected TLS relocation"));
 432         }
 433     }
 434
 435     // Do a relocation.  Return false if the caller should not issue
 436     // any warnings about this relocation.
 437     inline bool
 438     relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
 439              size_t relnum, const elfcpp::Rela<64, false>&,
 440              unsigned int r_type, const Sized_symbol<64>*,
 441              const Symbol_value<64>*,
 442              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 443              section_size_type);
 444
 445    private:
 446     // Do a TLS relocation.
 447     inline void
 448     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 449                  size_t relnum, const elfcpp::Rela<64, false>&,
 450                  unsigned int r_type, const Sized_symbol<64>*,
 451                  const Symbol_value<64>*,
 452                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 453                  section_size_type);
 454
 455     // Do a TLS General-Dynamic to Initial-Exec transition.
 456     inline void
 457     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 458                  Output_segment* tls_segment,
 459                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 460                  elfcpp::Elf_types<64>::Elf_Addr value,
 461                  unsigned char* view,
 462                  elfcpp::Elf_types<64>::Elf_Addr,
 463                  section_size_type view_size);
 464
 465     // Do a TLS General-Dynamic to Local-Exec transition.
 466     inline void
 467     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 468                  Output_segment* tls_segment,
 469                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 470                  elfcpp::Elf_types<64>::Elf_Addr value,
 471                  unsigned char* view,
 472                  section_size_type view_size);
 473
 474     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 475     inline void
 476     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 477                       Output_segment* tls_segment,
 478                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 479                       elfcpp::Elf_types<64>::Elf_Addr value,
 480                       unsigned char* view,
 481                       elfcpp::Elf_types<64>::Elf_Addr,
 482                       section_size_type view_size);
 483
 484     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 485     inline void
 486     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 487                       Output_segment* tls_segment,
 488                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 489                       elfcpp::Elf_types<64>::Elf_Addr value,
 490                       unsigned char* view,
 491                       section_size_type view_size);
 492
 493     // Do a TLS Local-Dynamic to Local-Exec transition.
 494     inline void
 495     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 496                  Output_segment* tls_segment,
 497                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 498                  elfcpp::Elf_types<64>::Elf_Addr value,
 499                  unsigned char* view,
 500                  section_size_type view_size);
 501
 502     // Do a TLS Initial-Exec to Local-Exec transition.
 503     static inline void
 504     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 505                  Output_segment* tls_segment,
 506                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 507                  elfcpp::Elf_types<64>::Elf_Addr value,
 508                  unsigned char* view,
 509                  section_size_type view_size);
 510
 511     // This is set if we should skip the next reloc, which should be a
 512     // PLT32 reloc against ___tls_get_addr.
 513     bool skip_call_tls_get_addr_;
 514
 515     // This is set if we see a relocation which could load the address
 516     // of the TLS block.  Whether we see such a relocation determines
 517     // how we handle the R_X86_64_DTPOFF32 relocation, which is used
 518     // in debugging sections.
 519     bool saw_tls_block_reloc_;
 520   };
 521
 522   // A class which returns the size required for a relocation type,
 523   // used while scanning relocs during a relocatable link.
 524   class Relocatable_size_for_reloc
 525   {
 526    public:
 527     unsigned int
 528     get_size_for_reloc(unsigned int, Relobj*);
 529   };
 530
 531   // Adjust TLS relocation type based on the options and whether this
 532   // is a local symbol.
 533   static tls::Tls_optimization
 534   optimize_tls_reloc(bool is_final, int r_type);
 535
 536   // Get the GOT section, creating it if necessary.
 537   Output_data_got<64, false>*
 538   got_section(Symbol_table*, Layout*);
 539
 540   // Get the GOT PLT section.
 541   Output_data_space*
 542   got_plt_section() const
 543   {
 544     gold_assert(this->got_plt_ != NULL);
 545     return this->got_plt_;
 546   }
 547
 548   // Get the GOT section for TLSDESC entries.
 549   Output_data_got<64, false>*
 550   got_tlsdesc_section() const
 551   {
 552     gold_assert(this->got_tlsdesc_ != NULL);
 553     return this->got_tlsdesc_;
 554   }
 555
 556   // Create the PLT section.
 557   void
 558   make_plt_section(Symbol_table* symtab, Layout* layout);
 559
 560   // Create a PLT entry for a global symbol.
 561   void
 562   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 563
 564   // Create a PLT entry for a local STT_GNU_IFUNC symbol.
 565   void
 566   make_local_ifunc_plt_entry(Symbol_table*, Layout*,
 567                              Sized_relobj<64, false>* relobj,
 568                              unsigned int local_sym_index);
 569
 570   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 571   void
 572   define_tls_base_symbol(Symbol_table*, Layout*);
 573
 574   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 575   void
 576   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 577
 578   // Create a GOT entry for the TLS module index.
 579   unsigned int
 580   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 581                       Sized_relobj<64, false>* object);
 582
 583   // Get the PLT section.
 584   Output_data_plt_x86_64*
 585   plt_section() const
 586   {
 587     gold_assert(this->plt_ != NULL);
 588     return this->plt_;
 589   }
 590
 591   // Get the dynamic reloc section, creating it if necessary.
 592   Reloc_section*
 593   rela_dyn_section(Layout*);
 594
 595   // Get the section to use for TLSDESC relocations.
 596   Reloc_section*
 597   rela_tlsdesc_section(Layout*) const;
 598
 599   // Add a potential copy relocation.
 600   void
 601   copy_reloc(Symbol_table* symtab, Layout* layout,
 602              Sized_relobj<64, false>* object,
 603              unsigned int shndx, Output_section* output_section,
 604              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 605   {
 606     this->copy_relocs_.copy_reloc(symtab, layout,
 607                                   symtab->get_sized_symbol<64>(sym),
 608                                   object, shndx, output_section,
 609                                   reloc, this->rela_dyn_section(layout));
 610   }
 611
 612   // Information about this specific target which we pass to the
 613   // general Target structure.
 614   static const Target::Target_info x86_64_info;
 615
 616   // The types of GOT entries needed for this platform.
 617   // These values are exposed to the ABI in an incremental link.
 618   // Do not renumber existing values without changing the version
 619   // number of the .gnu_incremental_inputs section.
 620   enum Got_type
 621   {
 622     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 623     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 624     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 625     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 626   };
 627
 628   // This type is used as the argument to the target specific
 629   // relocation routines.  The only target specific reloc is
 630   // R_X86_64_TLSDESC against a local symbol.
 631   struct Tlsdesc_info
 632   {
 633     Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym)
 634       : object(a_object), r_sym(a_r_sym)
 635     { }
 636
 637     // The object in which the local symbol is defined.
 638     Sized_relobj<64, false>* object;
 639     // The local symbol index in the object.
 640     unsigned int r_sym;
 641   };
 642
 643   // The GOT section.
 644   Output_data_got<64, false>* got_;
 645   // The PLT section.
 646   Output_data_plt_x86_64* plt_;
 647   // The GOT PLT section.
 648   Output_data_space* got_plt_;
 649   // The GOT section for TLSDESC relocations.
 650   Output_data_got<64, false>* got_tlsdesc_;
 651   // The _GLOBAL_OFFSET_TABLE_ symbol.
 652   Symbol* global_offset_table_;
 653   // The dynamic reloc section.
 654   Reloc_section* rela_dyn_;
 655   // Relocs saved to avoid a COPY reloc.
 656   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 657   // Space for variables copied with a COPY reloc.
 658   Output_data_space* dynbss_;
 659   // Offset of the GOT entry for the TLS module index.
 660   unsigned int got_mod_index_offset_;
 661   // We handle R_X86_64_TLSDESC against a local symbol as a target
 662   // specific relocation.  Here we store the object and local symbol
 663   // index for the relocation.
 664   std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
 665   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 666   bool tls_base_symbol_defined_;
 667 };
 668
 669 const Target::Target_info Target_x86_64::x86_64_info =
 670 {
 671   64,                   // size
 672   false,                // is_big_endian
 673   elfcpp::EM_X86_64,    // machine_code
 674   false,                // has_make_symbol
 675   false,                // has_resolve
 676   true,                 // has_code_fill
 677   true,                 // is_default_stack_executable
 678   '\0',                 // wrap_char
 679   "/lib/ld64.so.1",     // program interpreter
 680   0x400000,             // default_text_segment_address
 681   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 682   0x1000,               // common_pagesize (overridable by -z common-page-size)
 683   elfcpp::SHN_UNDEF,    // small_common_shndx
 684   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 685   0,                    // small_common_section_flags
 686   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 687   NULL,                 // attributes_section
 688   NULL                  // attributes_vendor
 689 };
 690
 691 // This is called when a new output section is created.  This is where
 692 // we handle the SHF_X86_64_LARGE.
 693
 694 void
 695 Target_x86_64::do_new_output_section(Output_section *os) const
 696 {
 697   if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
 698     os->set_is_large_section();
 699 }
 700
 701 // Get the GOT section, creating it if necessary.
 702
 703 Output_data_got<64, false>*
 704 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 705 {
 706   if (this->got_ == NULL)
 707     {
 708       gold_assert(symtab != NULL && layout != NULL);
 709
 710       this->got_ = new Output_data_got<64, false>();
 711
 712       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 713                                       (elfcpp::SHF_ALLOC
 714                                        | elfcpp::SHF_WRITE),
 715                                       this->got_, ORDER_RELRO_LAST,
 716                                       true);
 717
 718       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 719       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 720                                       (elfcpp::SHF_ALLOC
 721                                        | elfcpp::SHF_WRITE),
 722                                       this->got_plt_, ORDER_NON_RELRO_FIRST,
 723                                       false);
 724
 725       // The first three entries are reserved.
 726       this->got_plt_->set_current_data_size(3 * 8);
 727
 728       // Those bytes can go into the relro segment.
 729       layout->increase_relro(3 * 8);
 730
 731       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 732       this->global_offset_table_ =
 733         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 734                                       Symbol_table::PREDEFINED,
 735                                       this->got_plt_,
 736                                       0, 0, elfcpp::STT_OBJECT,
 737                                       elfcpp::STB_LOCAL,
 738                                       elfcpp::STV_HIDDEN, 0,
 739                                       false, false);
 740
 741       // If there are any TLSDESC relocations, they get GOT entries in
 742       // .got.plt after the jump slot entries.
 743       this->got_tlsdesc_ = new Output_data_got<64, false>();
 744       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 745                                       (elfcpp::SHF_ALLOC
 746                                        | elfcpp::SHF_WRITE),
 747                                       this->got_tlsdesc_,
 748                                       ORDER_NON_RELRO_FIRST, false);
 749     }
 750
 751   return this->got_;
 752 }
 753
 754 // Get the dynamic reloc section, creating it if necessary.
 755
 756 Target_x86_64::Reloc_section*
 757 Target_x86_64::rela_dyn_section(Layout* layout)
 758 {
 759   if (this->rela_dyn_ == NULL)
 760     {
 761       gold_assert(layout != NULL);
 762       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 763       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 764                                       elfcpp::SHF_ALLOC, this->rela_dyn_,
 765                                       ORDER_DYNAMIC_RELOCS, false);
 766     }
 767   return this->rela_dyn_;
 768 }
 769
 770 // Create the PLT section.  The ordinary .got section is an argument,
 771 // since we need to refer to the start.  We also create our own .got
 772 // section just for PLT entries.
 773
 774 Output_data_plt_x86_64::Output_data_plt_x86_64(Symbol_table* symtab,
 775                                                Layout* layout,
 776                                                Output_data_got<64, false>* got,
 777                                                Output_data_space* got_plt)
 778   : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
 779     count_(0), tlsdesc_got_offset_(-1U)
 780 {
 781   this->rel_ = new Reloc_section(false);
 782   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 783                                   elfcpp::SHF_ALLOC, this->rel_,
 784                                   ORDER_DYNAMIC_PLT_RELOCS, false);
 785
 786   if (parameters->doing_static_link())
 787     {
 788       // A statically linked executable will only have a .rela.plt
 789       // section to hold R_X86_64_IRELATIVE relocs for STT_GNU_IFUNC
 790       // symbols.  The library will use these symbols to locate the
 791       // IRELATIVE relocs at program startup time.
 792       symtab->define_in_output_data("__rela_iplt_start", NULL,
 793                                     Symbol_table::PREDEFINED,
 794                                     this->rel_, 0, 0, elfcpp::STT_NOTYPE,
 795                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
 796                                     0, false, true);
 797       symtab->define_in_output_data("__rela_iplt_end", NULL,
 798                                     Symbol_table::PREDEFINED,
 799                                     this->rel_, 0, 0, elfcpp::STT_NOTYPE,
 800                                     elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
 801                                     0, true, true);
 802     }
 803 }
 804
 805 void
 806 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 807 {
 808   os->set_entsize(plt_entry_size);
 809 }
 810
 811 // Add an entry to the PLT.
 812
 813 void
 814 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 815 {
 816   gold_assert(!gsym->has_plt_offset());
 817
 818   // Note that when setting the PLT offset we skip the initial
 819   // reserved PLT entry.
 820   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 821
 822   ++this->count_;
 823
 824   section_offset_type got_offset = this->got_plt_->current_data_size();
 825
 826   // Every PLT entry needs a GOT entry which points back to the PLT
 827   // entry (this will be changed by the dynamic linker, normally
 828   // lazily when the function is called).
 829   this->got_plt_->set_current_data_size(got_offset + 8);
 830
 831   // Every PLT entry needs a reloc.
 832   if (gsym->type() == elfcpp::STT_GNU_IFUNC
 833       && gsym->can_use_relative_reloc(false))
 834     this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
 835                                              this->got_plt_, got_offset, 0);
 836   else
 837     {
 838       gsym->set_needs_dynsym_entry();
 839       this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 840                              got_offset, 0);
 841     }
 842
 843   // Note that we don't need to save the symbol.  The contents of the
 844   // PLT are independent of which symbols are used.  The symbols only
 845   // appear in the relocations.
 846 }
 847
 848 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.  Return
 849 // the PLT offset.
 850
 851 unsigned int
 852 Output_data_plt_x86_64::add_local_ifunc_entry(Sized_relobj<64, false>* relobj,
 853                                               unsigned int local_sym_index)
 854 {
 855   unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
 856   ++this->count_;
 857
 858   section_offset_type got_offset = this->got_plt_->current_data_size();
 859
 860   // Every PLT entry needs a GOT entry which points back to the PLT
 861   // entry.
 862   this->got_plt_->set_current_data_size(got_offset + 8);
 863
 864   // Every PLT entry needs a reloc.
 865   this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
 866                                           elfcpp::R_X86_64_IRELATIVE,
 867                                           this->got_plt_, got_offset, 0);
 868
 869   return plt_offset;
 870 }
 871
 872 // Return where the TLSDESC relocations should go, creating it if
 873 // necessary.  These follow the JUMP_SLOT relocations.
 874
 875 Output_data_plt_x86_64::Reloc_section*
 876 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
 877 {
 878   if (this->tlsdesc_rel_ == NULL)
 879     {
 880       this->tlsdesc_rel_ = new Reloc_section(false);
 881       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 882                                       elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
 883                                       ORDER_DYNAMIC_PLT_RELOCS, false);
 884       gold_assert(this->tlsdesc_rel_->output_section() ==
 885                   this->rel_->output_section());
 886     }
 887   return this->tlsdesc_rel_;
 888 }
 889
 890 // Set the final size.
 891 void
 892 Output_data_plt_x86_64::set_final_data_size()
 893 {
 894   unsigned int count = this->count_;
 895   if (this->has_tlsdesc_entry())
 896     ++count;
 897   this->set_data_size((count + 1) * plt_entry_size);
 898 }
 899
 900 // The first entry in the PLT for an executable.
 901
 902 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 903 {
 904   // From AMD64 ABI Draft 0.98, page 76
 905   0xff, 0x35,   // pushq contents of memory address
 906   0, 0, 0, 0,   // replaced with address of .got + 8
 907   0xff, 0x25,   // jmp indirect
 908   0, 0, 0, 0,   // replaced with address of .got + 16
 909   0x90, 0x90, 0x90, 0x90   // noop (x4)
 910 };
 911
 912 // Subsequent entries in the PLT for an executable.
 913
 914 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 915 {
 916   // From AMD64 ABI Draft 0.98, page 76
 917   0xff, 0x25,   // jmpq indirect
 918   0, 0, 0, 0,   // replaced with address of symbol in .got
 919   0x68,         // pushq immediate
 920   0, 0, 0, 0,   // replaced with offset into relocation table
 921   0xe9,         // jmpq relative
 922   0, 0, 0, 0    // replaced with offset to start of .plt
 923 };
 924
 925 // The reserved TLSDESC entry in the PLT for an executable.
 926
 927 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 928 {
 929   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 930   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 931   0xff, 0x35,   // pushq x(%rip)
 932   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 933   0xff, 0x25,   // jmpq *y(%rip)
 934   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 935   0x0f, 0x1f,   // nop
 936   0x40, 0
 937 };
 938
 939 // Write out the PLT.  This uses the hand-coded instructions above,
 940 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 941
 942 void
 943 Output_data_plt_x86_64::do_write(Output_file* of)
 944 {
 945   const off_t offset = this->offset();
 946   const section_size_type oview_size =
 947     convert_to_section_size_type(this->data_size());
 948   unsigned char* const oview = of->get_output_view(offset, oview_size);
 949
 950   const off_t got_file_offset = this->got_plt_->offset();
 951   const section_size_type got_size =
 952     convert_to_section_size_type(this->got_plt_->data_size());
 953   unsigned char* const got_view = of->get_output_view(got_file_offset,
 954                                                       got_size);
 955
 956   unsigned char* pov = oview;
 957
 958   // The base address of the .plt section.
 959   elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
 960   // The base address of the .got section.
 961   elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
 962   // The base address of the PLT portion of the .got section,
 963   // which is where the GOT pointer will point, and where the
 964   // three reserved GOT entries are located.
 965   elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
 966
 967   memcpy(pov, first_plt_entry, plt_entry_size);
 968   // We do a jmp relative to the PC at the end of this instruction.
 969   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 970                                               (got_address + 8
 971                                                - (plt_address + 6)));
 972   elfcpp::Swap<32, false>::writeval(pov + 8,
 973                                     (got_address + 16
 974                                      - (plt_address + 12)));
 975   pov += plt_entry_size;
 976
 977   unsigned char* got_pov = got_view;
 978
 979   memset(got_pov, 0, 24);
 980   got_pov += 24;
 981
 982   unsigned int plt_offset = plt_entry_size;
 983   unsigned int got_offset = 24;
 984   const unsigned int count = this->count_;
 985   for (unsigned int plt_index = 0;
 986        plt_index < count;
 987        ++plt_index,
 988          pov += plt_entry_size,
 989          got_pov += 8,
 990          plt_offset += plt_entry_size,
 991          got_offset += 8)
 992     {
 993       // Set and adjust the PLT entry itself.
 994       memcpy(pov, plt_entry, plt_entry_size);
 995       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 996                                                   (got_address + got_offset
 997                                                    - (plt_address + plt_offset
 998                                                       + 6)));
 999
1000       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
1001       elfcpp::Swap<32, false>::writeval(pov + 12,
1002                                         - (plt_offset + plt_entry_size));
1003
1004       // Set the entry in the GOT.
1005       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
1006     }
1007
1008   if (this->has_tlsdesc_entry())
1009     {
1010       // Set and adjust the reserved TLSDESC PLT entry.
1011       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
1012       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
1013       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1014                                                   (got_address + 8
1015                                                    - (plt_address + plt_offset
1016                                                       + 6)));
1017       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
1018                                                   (got_base
1019                                                    + tlsdesc_got_offset
1020                                                    - (plt_address + plt_offset
1021                                                       + 12)));
1022       pov += plt_entry_size;
1023     }
1024
1025   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1026   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1027
1028   of->write_output_view(offset, oview_size, oview);
1029   of->write_output_view(got_file_offset, got_size, got_view);
1030 }
1031
1032 // Create the PLT section.
1033
1034 void
1035 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
1036 {
1037   if (this->plt_ == NULL)
1038     {
1039       // Create the GOT sections first.
1040       this->got_section(symtab, layout);
1041
1042       this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
1043                                               this->got_plt_);
1044       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1045                                       (elfcpp::SHF_ALLOC
1046                                        | elfcpp::SHF_EXECINSTR),
1047                                       this->plt_, ORDER_PLT, false);
1048
1049       // Make the sh_info field of .rela.plt point to .plt.
1050       Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1051       rela_plt_os->set_info_section(this->plt_->output_section());
1052     }
1053 }
1054
1055 // Return the section for TLSDESC relocations.
1056
1057 Target_x86_64::Reloc_section*
1058 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
1059 {
1060   return this->plt_section()->rela_tlsdesc(layout);
1061 }
1062
1063 // Create a PLT entry for a global symbol.
1064
1065 void
1066 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
1067                               Symbol* gsym)
1068 {
1069   if (gsym->has_plt_offset())
1070     return;
1071
1072   if (this->plt_ == NULL)
1073     this->make_plt_section(symtab, layout);
1074
1075   this->plt_->add_entry(gsym);
1076 }
1077
1078 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1079
1080 void
1081 Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
1082                                           Sized_relobj<64, false>* relobj,
1083                                           unsigned int local_sym_index)
1084 {
1085   if (relobj->local_has_plt_offset(local_sym_index))
1086     return;
1087   if (this->plt_ == NULL)
1088     this->make_plt_section(symtab, layout);
1089   unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj,
1090                                                               local_sym_index);
1091   relobj->set_local_plt_offset(local_sym_index, plt_offset);
1092 }
1093
1094 // Return the number of entries in the PLT.
1095
1096 unsigned int
1097 Target_x86_64::plt_entry_count() const
1098 {
1099   if (this->plt_ == NULL)
1100     return 0;
1101   return this->plt_->entry_count();
1102 }
1103
1104 // Return the offset of the first non-reserved PLT entry.
1105
1106 unsigned int
1107 Target_x86_64::first_plt_entry_offset() const
1108 {
1109   return Output_data_plt_x86_64::first_plt_entry_offset();
1110 }
1111
1112 // Return the size of each PLT entry.
1113
1114 unsigned int
1115 Target_x86_64::plt_entry_size() const
1116 {
1117   return Output_data_plt_x86_64::get_plt_entry_size();
1118 }
1119
1120 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1121
1122 void
1123 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1124 {
1125   if (this->tls_base_symbol_defined_)
1126     return;
1127
1128   Output_segment* tls_segment = layout->tls_segment();
1129   if (tls_segment != NULL)
1130     {
1131       bool is_exec = parameters->options().output_is_executable();
1132       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1133                                        Symbol_table::PREDEFINED,
1134                                        tls_segment, 0, 0,
1135                                        elfcpp::STT_TLS,
1136                                        elfcpp::STB_LOCAL,
1137                                        elfcpp::STV_HIDDEN, 0,
1138                                        (is_exec
1139                                         ? Symbol::SEGMENT_END
1140                                         : Symbol::SEGMENT_START),
1141                                        true);
1142     }
1143   this->tls_base_symbol_defined_ = true;
1144 }
1145
1146 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1147
1148 void
1149 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
1150                                              Layout* layout)
1151 {
1152   if (this->plt_ == NULL)
1153     this->make_plt_section(symtab, layout);
1154
1155   if (!this->plt_->has_tlsdesc_entry())
1156     {
1157       // Allocate the TLSDESC_GOT entry.
1158       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1159       unsigned int got_offset = got->add_constant(0);
1160
1161       // Allocate the TLSDESC_PLT entry.
1162       this->plt_->reserve_tlsdesc_entry(got_offset);
1163     }
1164 }
1165
1166 // Create a GOT entry for the TLS module index.
1167
1168 unsigned int
1169 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1170                                    Sized_relobj<64, false>* object)
1171 {
1172   if (this->got_mod_index_offset_ == -1U)
1173     {
1174       gold_assert(symtab != NULL && layout != NULL && object != NULL);
1175       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1176       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1177       unsigned int got_offset = got->add_constant(0);
1178       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1179                           got_offset, 0);
1180       got->add_constant(0);
1181       this->got_mod_index_offset_ = got_offset;
1182     }
1183   return this->got_mod_index_offset_;
1184 }
1185
1186 // Optimize the TLS relocation type based on what we know about the
1187 // symbol.  IS_FINAL is true if the final address of this symbol is
1188 // known at link time.
1189
1190 tls::Tls_optimization
1191 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1192 {
1193   // If we are generating a shared library, then we can't do anything
1194   // in the linker.
1195   if (parameters->options().shared())
1196     return tls::TLSOPT_NONE;
1197
1198   switch (r_type)
1199     {
1200     case elfcpp::R_X86_64_TLSGD:
1201     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1202     case elfcpp::R_X86_64_TLSDESC_CALL:
1203       // These are General-Dynamic which permits fully general TLS
1204       // access.  Since we know that we are generating an executable,
1205       // we can convert this to Initial-Exec.  If we also know that
1206       // this is a local symbol, we can further switch to Local-Exec.
1207       if (is_final)
1208         return tls::TLSOPT_TO_LE;
1209       return tls::TLSOPT_TO_IE;
1210
1211     case elfcpp::R_X86_64_TLSLD:
1212       // This is Local-Dynamic, which refers to a local symbol in the
1213       // dynamic TLS block.  Since we know that we generating an
1214       // executable, we can switch to Local-Exec.
1215       return tls::TLSOPT_TO_LE;
1216
1217     case elfcpp::R_X86_64_DTPOFF32:
1218     case elfcpp::R_X86_64_DTPOFF64:
1219       // Another Local-Dynamic reloc.
1220       return tls::TLSOPT_TO_LE;
1221
1222     case elfcpp::R_X86_64_GOTTPOFF:
1223       // These are Initial-Exec relocs which get the thread offset
1224       // from the GOT.  If we know that we are linking against the
1225       // local symbol, we can switch to Local-Exec, which links the
1226       // thread offset into the instruction.
1227       if (is_final)
1228         return tls::TLSOPT_TO_LE;
1229       return tls::TLSOPT_NONE;
1230
1231     case elfcpp::R_X86_64_TPOFF32:
1232       // When we already have Local-Exec, there is nothing further we
1233       // can do.
1234       return tls::TLSOPT_NONE;
1235
1236     default:
1237       gold_unreachable();
1238     }
1239 }
1240
1241 // Report an unsupported relocation against a local symbol.
1242
1243 void
1244 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
1245                                              unsigned int r_type)
1246 {
1247   gold_error(_("%s: unsupported reloc %u against local symbol"),
1248              object->name().c_str(), r_type);
1249 }
1250
1251 // We are about to emit a dynamic relocation of type R_TYPE.  If the
1252 // dynamic linker does not support it, issue an error.  The GNU linker
1253 // only issues a non-PIC error for an allocated read-only section.
1254 // Here we know the section is allocated, but we don't know that it is
1255 // read-only.  But we check for all the relocation types which the
1256 // glibc dynamic linker supports, so it seems appropriate to issue an
1257 // error even if the section is not read-only.
1258
1259 void
1260 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
1261 {
1262   switch (r_type)
1263     {
1264       // These are the relocation types supported by glibc for x86_64.
1265     case elfcpp::R_X86_64_RELATIVE:
1266     case elfcpp::R_X86_64_IRELATIVE:
1267     case elfcpp::R_X86_64_GLOB_DAT:
1268     case elfcpp::R_X86_64_JUMP_SLOT:
1269     case elfcpp::R_X86_64_DTPMOD64:
1270     case elfcpp::R_X86_64_DTPOFF64:
1271     case elfcpp::R_X86_64_TPOFF64:
1272     case elfcpp::R_X86_64_64:
1273     case elfcpp::R_X86_64_32:
1274     case elfcpp::R_X86_64_PC32:
1275     case elfcpp::R_X86_64_COPY:
1276       return;
1277
1278     default:
1279       // This prevents us from issuing more than one error per reloc
1280       // section.  But we can still wind up issuing more than one
1281       // error per object file.
1282       if (this->issued_non_pic_error_)
1283         return;
1284       gold_assert(parameters->options().output_is_position_independent());
1285       object->error(_("requires unsupported dynamic reloc; "
1286                       "recompile with -fPIC"));
1287       this->issued_non_pic_error_ = true;
1288       return;
1289
1290     case elfcpp::R_X86_64_NONE:
1291       gold_unreachable();
1292     }
1293 }
1294
1295 // Return whether we need to make a PLT entry for a relocation of the
1296 // given type against a STT_GNU_IFUNC symbol.
1297
1298 bool
1299 Target_x86_64::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<64, false>* object,
1300                                                unsigned int r_type)
1301 {
1302   switch (r_type)
1303     {
1304     case elfcpp::R_X86_64_NONE:
1305     case elfcpp::R_X86_64_GNU_VTINHERIT:
1306     case elfcpp::R_X86_64_GNU_VTENTRY:
1307       return false;
1308
1309     case elfcpp::R_X86_64_64:
1310     case elfcpp::R_X86_64_32:
1311     case elfcpp::R_X86_64_32S:
1312     case elfcpp::R_X86_64_16:
1313     case elfcpp::R_X86_64_8:
1314     case elfcpp::R_X86_64_PC64:
1315     case elfcpp::R_X86_64_PC32:
1316     case elfcpp::R_X86_64_PC16:
1317     case elfcpp::R_X86_64_PC8:
1318     case elfcpp::R_X86_64_PLT32:
1319     case elfcpp::R_X86_64_GOTPC32:
1320     case elfcpp::R_X86_64_GOTOFF64:
1321     case elfcpp::R_X86_64_GOTPC64:
1322     case elfcpp::R_X86_64_PLTOFF64:
1323     case elfcpp::R_X86_64_GOT64:
1324     case elfcpp::R_X86_64_GOT32:
1325     case elfcpp::R_X86_64_GOTPCREL64:
1326     case elfcpp::R_X86_64_GOTPCREL:
1327     case elfcpp::R_X86_64_GOTPLT64:
1328       return true;
1329
1330     case elfcpp::R_X86_64_COPY:
1331     case elfcpp::R_X86_64_GLOB_DAT:
1332     case elfcpp::R_X86_64_JUMP_SLOT:
1333     case elfcpp::R_X86_64_RELATIVE:
1334     case elfcpp::R_X86_64_IRELATIVE:
1335     case elfcpp::R_X86_64_TPOFF64:
1336     case elfcpp::R_X86_64_DTPMOD64:
1337     case elfcpp::R_X86_64_TLSDESC:
1338       // We will give an error later.
1339       return false;
1340
1341     case elfcpp::R_X86_64_TLSGD:
1342     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1343     case elfcpp::R_X86_64_TLSDESC_CALL:
1344     case elfcpp::R_X86_64_TLSLD:
1345     case elfcpp::R_X86_64_DTPOFF32:
1346     case elfcpp::R_X86_64_DTPOFF64:
1347     case elfcpp::R_X86_64_GOTTPOFF:
1348     case elfcpp::R_X86_64_TPOFF32:
1349       gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
1350                  object->name().c_str(), r_type);
1351       return false;
1352
1353     case elfcpp::R_X86_64_SIZE32:
1354     case elfcpp::R_X86_64_SIZE64:
1355     default:
1356       // We will give an error later.
1357       return false;
1358     }
1359 }
1360
1361 // Scan a relocation for a local symbol.
1362
1363 inline void
1364 Target_x86_64::Scan::local(Symbol_table* symtab,
1365                            Layout* layout,
1366                            Target_x86_64* target,
1367                            Sized_relobj<64, false>* object,
1368                            unsigned int data_shndx,
1369                            Output_section* output_section,
1370                            const elfcpp::Rela<64, false>& reloc,
1371                            unsigned int r_type,
1372                            const elfcpp::Sym<64, false>& lsym)
1373 {
1374   // A local STT_GNU_IFUNC symbol may require a PLT entry.
1375   if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
1376       && this->reloc_needs_plt_for_ifunc(object, r_type))
1377     {
1378       unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1379       target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
1380     }
1381
1382   switch (r_type)
1383     {
1384     case elfcpp::R_X86_64_NONE:
1385     case elfcpp::R_X86_64_GNU_VTINHERIT:
1386     case elfcpp::R_X86_64_GNU_VTENTRY:
1387       break;
1388
1389     case elfcpp::R_X86_64_64:
1390       // If building a shared library (or a position-independent
1391       // executable), we need to create a dynamic relocation for this
1392       // location.  The relocation applied at link time will apply the
1393       // link-time value, so we flag the location with an
1394       // R_X86_64_RELATIVE relocation so the dynamic loader can
1395       // relocate it easily.
1396       if (parameters->options().output_is_position_independent())
1397         {
1398           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1399           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1400           rela_dyn->add_local_relative(object, r_sym,
1401                                        elfcpp::R_X86_64_RELATIVE,
1402                                        output_section, data_shndx,
1403                                        reloc.get_r_offset(),
1404                                        reloc.get_r_addend());
1405         }
1406       break;
1407
1408     case elfcpp::R_X86_64_32:
1409     case elfcpp::R_X86_64_32S:
1410     case elfcpp::R_X86_64_16:
1411     case elfcpp::R_X86_64_8:
1412       // If building a shared library (or a position-independent
1413       // executable), we need to create a dynamic relocation for this
1414       // location.  We can't use an R_X86_64_RELATIVE relocation
1415       // because that is always a 64-bit relocation.
1416       if (parameters->options().output_is_position_independent())
1417         {
1418           this->check_non_pic(object, r_type);
1419
1420           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1421           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1422           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1423             rela_dyn->add_local(object, r_sym, r_type, output_section,
1424                                 data_shndx, reloc.get_r_offset(),
1425                                 reloc.get_r_addend());
1426           else
1427             {
1428               gold_assert(lsym.get_st_value() == 0);
1429               unsigned int shndx = lsym.get_st_shndx();
1430               bool is_ordinary;
1431               shndx = object->adjust_sym_shndx(r_sym, shndx,
1432                                                &is_ordinary);
1433               if (!is_ordinary)
1434                 object->error(_("section symbol %u has bad shndx %u"),
1435                               r_sym, shndx);
1436               else
1437                 rela_dyn->add_local_section(object, shndx,
1438                                             r_type, output_section,
1439                                             data_shndx, reloc.get_r_offset(),
1440                                             reloc.get_r_addend());
1441             }
1442         }
1443       break;
1444
1445     case elfcpp::R_X86_64_PC64:
1446     case elfcpp::R_X86_64_PC32:
1447     case elfcpp::R_X86_64_PC16:
1448     case elfcpp::R_X86_64_PC8:
1449       break;
1450
1451     case elfcpp::R_X86_64_PLT32:
1452       // Since we know this is a local symbol, we can handle this as a
1453       // PC32 reloc.
1454       break;
1455
1456     case elfcpp::R_X86_64_GOTPC32:
1457     case elfcpp::R_X86_64_GOTOFF64:
1458     case elfcpp::R_X86_64_GOTPC64:
1459     case elfcpp::R_X86_64_PLTOFF64:
1460       // We need a GOT section.
1461       target->got_section(symtab, layout);
1462       // For PLTOFF64, we'd normally want a PLT section, but since we
1463       // know this is a local symbol, no PLT is needed.
1464       break;
1465
1466     case elfcpp::R_X86_64_GOT64:
1467     case elfcpp::R_X86_64_GOT32:
1468     case elfcpp::R_X86_64_GOTPCREL64:
1469     case elfcpp::R_X86_64_GOTPCREL:
1470     case elfcpp::R_X86_64_GOTPLT64:
1471       {
1472         // The symbol requires a GOT entry.
1473         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1474         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1475
1476         // For a STT_GNU_IFUNC symbol we want the PLT offset.  That
1477         // lets function pointers compare correctly with shared
1478         // libraries.  Otherwise we would need an IRELATIVE reloc.
1479         bool is_new;
1480         if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
1481           is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
1482         else
1483           is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
1484         if (is_new)
1485           {
1486             // If we are generating a shared object, we need to add a
1487             // dynamic relocation for this symbol's GOT entry.
1488             if (parameters->options().output_is_position_independent())
1489               {
1490                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1491                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1492                 if (r_type != elfcpp::R_X86_64_GOT32)
1493                   {
1494                     unsigned int got_offset =
1495                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
1496                     rela_dyn->add_local_relative(object, r_sym,
1497                                                  elfcpp::R_X86_64_RELATIVE,
1498                                                  got, got_offset, 0);
1499                   }
1500                 else
1501                   {
1502                     this->check_non_pic(object, r_type);
1503
1504                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1505                     rela_dyn->add_local(
1506                         object, r_sym, r_type, got,
1507                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1508                   }
1509               }
1510           }
1511         // For GOTPLT64, we'd normally want a PLT section, but since
1512         // we know this is a local symbol, no PLT is needed.
1513       }
1514       break;
1515
1516     case elfcpp::R_X86_64_COPY:
1517     case elfcpp::R_X86_64_GLOB_DAT:
1518     case elfcpp::R_X86_64_JUMP_SLOT:
1519     case elfcpp::R_X86_64_RELATIVE:
1520     case elfcpp::R_X86_64_IRELATIVE:
1521       // These are outstanding tls relocs, which are unexpected when linking
1522     case elfcpp::R_X86_64_TPOFF64:
1523     case elfcpp::R_X86_64_DTPMOD64:
1524     case elfcpp::R_X86_64_TLSDESC:
1525       gold_error(_("%s: unexpected reloc %u in object file"),
1526                  object->name().c_str(), r_type);
1527       break;
1528
1529       // These are initial tls relocs, which are expected when linking
1530     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1531     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1532     case elfcpp::R_X86_64_TLSDESC_CALL:
1533     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1534     case elfcpp::R_X86_64_DTPOFF32:
1535     case elfcpp::R_X86_64_DTPOFF64:
1536     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1537     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1538       {
1539         bool output_is_shared = parameters->options().shared();
1540         const tls::Tls_optimization optimized_type
1541             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1542         switch (r_type)
1543           {
1544           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1545             if (optimized_type == tls::TLSOPT_NONE)
1546               {
1547                 // Create a pair of GOT entries for the module index and
1548                 // dtv-relative offset.
1549                 Output_data_got<64, false>* got
1550                     = target->got_section(symtab, layout);
1551                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1552                 unsigned int shndx = lsym.get_st_shndx();
1553                 bool is_ordinary;
1554                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1555                 if (!is_ordinary)
1556                   object->error(_("local symbol %u has bad shndx %u"),
1557                               r_sym, shndx);
1558                 else
1559                   got->add_local_pair_with_rela(object, r_sym,
1560                                                 shndx,
1561                                                 GOT_TYPE_TLS_PAIR,
1562                                                 target->rela_dyn_section(layout),
1563                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1564               }
1565             else if (optimized_type != tls::TLSOPT_TO_LE)
1566               unsupported_reloc_local(object, r_type);
1567             break;
1568
1569           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1570             target->define_tls_base_symbol(symtab, layout);
1571             if (optimized_type == tls::TLSOPT_NONE)
1572               {
1573                 // Create reserved PLT and GOT entries for the resolver.
1574                 target->reserve_tlsdesc_entries(symtab, layout);
1575
1576                 // Generate a double GOT entry with an
1577                 // R_X86_64_TLSDESC reloc.  The R_X86_64_TLSDESC reloc
1578                 // is resolved lazily, so the GOT entry needs to be in
1579                 // an area in .got.plt, not .got.  Call got_section to
1580                 // make sure the section has been created.
1581                 target->got_section(symtab, layout);
1582                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1583                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1584                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1585                   {
1586                     unsigned int got_offset = got->add_constant(0);
1587                     got->add_constant(0);
1588                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1589                                                  got_offset);
1590                     Reloc_section* rt = target->rela_tlsdesc_section(layout);
1591                     // We store the arguments we need in a vector, and
1592                     // use the index into the vector as the parameter
1593                     // to pass to the target specific routines.
1594                     uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
1595                     void* arg = reinterpret_cast<void*>(intarg);
1596                     rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1597                                             got, got_offset, 0);
1598                   }
1599               }
1600             else if (optimized_type != tls::TLSOPT_TO_LE)
1601               unsupported_reloc_local(object, r_type);
1602             break;
1603
1604           case elfcpp::R_X86_64_TLSDESC_CALL:
1605             break;
1606
1607           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1608             if (optimized_type == tls::TLSOPT_NONE)
1609               {
1610                 // Create a GOT entry for the module index.
1611                 target->got_mod_index_entry(symtab, layout, object);
1612               }
1613             else if (optimized_type != tls::TLSOPT_TO_LE)
1614               unsupported_reloc_local(object, r_type);
1615             break;
1616
1617           case elfcpp::R_X86_64_DTPOFF32:
1618           case elfcpp::R_X86_64_DTPOFF64:
1619             break;
1620
1621           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1622             layout->set_has_static_tls();
1623             if (optimized_type == tls::TLSOPT_NONE)
1624               {
1625                 // Create a GOT entry for the tp-relative offset.
1626                 Output_data_got<64, false>* got
1627                     = target->got_section(symtab, layout);
1628                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1629                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1630                                          target->rela_dyn_section(layout),
1631                                          elfcpp::R_X86_64_TPOFF64);
1632               }
1633             else if (optimized_type != tls::TLSOPT_TO_LE)
1634               unsupported_reloc_local(object, r_type);
1635             break;
1636
1637           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1638             layout->set_has_static_tls();
1639             if (output_is_shared)
1640               unsupported_reloc_local(object, r_type);
1641             break;
1642
1643           default:
1644             gold_unreachable();
1645           }
1646       }
1647       break;
1648
1649     case elfcpp::R_X86_64_SIZE32:
1650     case elfcpp::R_X86_64_SIZE64:
1651     default:
1652       gold_error(_("%s: unsupported reloc %u against local symbol"),
1653                  object->name().c_str(), r_type);
1654       break;
1655     }
1656 }
1657
1658
1659 // Report an unsupported relocation against a global symbol.
1660
1661 void
1662 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1663                                               unsigned int r_type,
1664                                               Symbol* gsym)
1665 {
1666   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1667              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1668 }
1669
1670 // Returns true if this relocation type could be that of a function pointer.
1671 inline bool
1672 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
1673 {
1674   switch (r_type)
1675     {
1676     case elfcpp::R_X86_64_64:
1677     case elfcpp::R_X86_64_32:
1678     case elfcpp::R_X86_64_32S:
1679     case elfcpp::R_X86_64_16:
1680     case elfcpp::R_X86_64_8:
1681     case elfcpp::R_X86_64_GOT64:
1682     case elfcpp::R_X86_64_GOT32:
1683     case elfcpp::R_X86_64_GOTPCREL64:
1684     case elfcpp::R_X86_64_GOTPCREL:
1685     case elfcpp::R_X86_64_GOTPLT64:
1686       {
1687         return true;
1688       }
1689     }
1690   return false;
1691 }
1692
1693 // For safe ICF, scan a relocation for a local symbol to check if it
1694 // corresponds to a function pointer being taken.  In that case mark
1695 // the function whose pointer was taken as not foldable.
1696
1697 inline bool
1698 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1699   Symbol_table* ,
1700   Layout* ,
1701   Target_x86_64* ,
1702   Sized_relobj<64, false>* ,
1703   unsigned int ,
1704   Output_section* ,
1705   const elfcpp::Rela<64, false>& ,
1706   unsigned int r_type,
1707   const elfcpp::Sym<64, false>&)
1708 {
1709   // When building a shared library, do not fold any local symbols as it is
1710   // not possible to distinguish pointer taken versus a call by looking at
1711   // the relocation types.
1712   return (parameters->options().shared()
1713           || possible_function_pointer_reloc(r_type));
1714 }
1715
1716 // For safe ICF, scan a relocation for a global symbol to check if it
1717 // corresponds to a function pointer being taken.  In that case mark
1718 // the function whose pointer was taken as not foldable.
1719
1720 inline bool
1721 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1722   Symbol_table*,
1723   Layout* ,
1724   Target_x86_64* ,
1725   Sized_relobj<64, false>* ,
1726   unsigned int ,
1727   Output_section* ,
1728   const elfcpp::Rela<64, false>& ,
1729   unsigned int r_type,
1730   Symbol* gsym)
1731 {
1732   // When building a shared library, do not fold symbols whose visibility
1733   // is hidden, internal or protected.
1734   return ((parameters->options().shared()
1735            && (gsym->visibility() == elfcpp::STV_INTERNAL
1736                || gsym->visibility() == elfcpp::STV_PROTECTED
1737                || gsym->visibility() == elfcpp::STV_HIDDEN))
1738           || possible_function_pointer_reloc(r_type));
1739 }
1740
1741 // Scan a relocation for a global symbol.
1742
1743 inline void
1744 Target_x86_64::Scan::global(Symbol_table* symtab,
1745                             Layout* layout,
1746                             Target_x86_64* target,
1747                             Sized_relobj<64, false>* object,
1748                             unsigned int data_shndx,
1749                             Output_section* output_section,
1750                             const elfcpp::Rela<64, false>& reloc,
1751                             unsigned int r_type,
1752                             Symbol* gsym)
1753 {
1754   // A STT_GNU_IFUNC symbol may require a PLT entry.
1755   if (gsym->type() == elfcpp::STT_GNU_IFUNC
1756       && this->reloc_needs_plt_for_ifunc(object, r_type))
1757     target->make_plt_entry(symtab, layout, gsym);
1758
1759   switch (r_type)
1760     {
1761     case elfcpp::R_X86_64_NONE:
1762     case elfcpp::R_X86_64_GNU_VTINHERIT:
1763     case elfcpp::R_X86_64_GNU_VTENTRY:
1764       break;
1765
1766     case elfcpp::R_X86_64_64:
1767     case elfcpp::R_X86_64_32:
1768     case elfcpp::R_X86_64_32S:
1769     case elfcpp::R_X86_64_16:
1770     case elfcpp::R_X86_64_8:
1771       {
1772         // Make a PLT entry if necessary.
1773         if (gsym->needs_plt_entry())
1774           {
1775             target->make_plt_entry(symtab, layout, gsym);
1776             // Since this is not a PC-relative relocation, we may be
1777             // taking the address of a function. In that case we need to
1778             // set the entry in the dynamic symbol table to the address of
1779             // the PLT entry.
1780             if (gsym->is_from_dynobj() && !parameters->options().shared())
1781               gsym->set_needs_dynsym_value();
1782           }
1783         // Make a dynamic relocation if necessary.
1784         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1785           {
1786             if (gsym->may_need_copy_reloc())
1787               {
1788                 target->copy_reloc(symtab, layout, object,
1789                                    data_shndx, output_section, gsym, reloc);
1790               }
1791             else if (r_type == elfcpp::R_X86_64_64
1792                      && gsym->type() == elfcpp::STT_GNU_IFUNC
1793                      && gsym->can_use_relative_reloc(false)
1794                      && !gsym->is_from_dynobj()
1795                      && !gsym->is_undefined()
1796                      && !gsym->is_preemptible())
1797               {
1798                 // Use an IRELATIVE reloc for a locally defined
1799                 // STT_GNU_IFUNC symbol.  This makes a function
1800                 // address in a PIE executable match the address in a
1801                 // shared library that it links against.
1802                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1803                 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
1804                 rela_dyn->add_symbolless_global_addend(gsym, r_type,
1805                                                        output_section, object,
1806                                                        data_shndx,
1807                                                        reloc.get_r_offset(),
1808                                                        reloc.get_r_addend());
1809               }
1810             else if (r_type == elfcpp::R_X86_64_64
1811                      && gsym->can_use_relative_reloc(false))
1812               {
1813                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1814                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1815                                               output_section, object,
1816                                               data_shndx,
1817                                               reloc.get_r_offset(),
1818                                               reloc.get_r_addend());
1819               }
1820             else
1821               {
1822                 this->check_non_pic(object, r_type);
1823                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1824                 rela_dyn->add_global(gsym, r_type, output_section, object,
1825                                      data_shndx, reloc.get_r_offset(),
1826                                      reloc.get_r_addend());
1827               }
1828           }
1829       }
1830       break;
1831
1832     case elfcpp::R_X86_64_PC64:
1833     case elfcpp::R_X86_64_PC32:
1834     case elfcpp::R_X86_64_PC16:
1835     case elfcpp::R_X86_64_PC8:
1836       {
1837         // Make a PLT entry if necessary.
1838         if (gsym->needs_plt_entry())
1839           target->make_plt_entry(symtab, layout, gsym);
1840         // Make a dynamic relocation if necessary.
1841         int flags = Symbol::NON_PIC_REF;
1842         if (gsym->is_func())
1843           flags |= Symbol::FUNCTION_CALL;
1844         if (gsym->needs_dynamic_reloc(flags))
1845           {
1846             if (gsym->may_need_copy_reloc())
1847               {
1848                 target->copy_reloc(symtab, layout, object,
1849                                    data_shndx, output_section, gsym, reloc);
1850               }
1851             else
1852               {
1853                 this->check_non_pic(object, r_type);
1854                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1855                 rela_dyn->add_global(gsym, r_type, output_section, object,
1856                                      data_shndx, reloc.get_r_offset(),
1857                                      reloc.get_r_addend());
1858               }
1859           }
1860       }
1861       break;
1862
1863     case elfcpp::R_X86_64_GOT64:
1864     case elfcpp::R_X86_64_GOT32:
1865     case elfcpp::R_X86_64_GOTPCREL64:
1866     case elfcpp::R_X86_64_GOTPCREL:
1867     case elfcpp::R_X86_64_GOTPLT64:
1868       {
1869         // The symbol requires a GOT entry.
1870         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1871         if (gsym->final_value_is_known())
1872           {
1873             // For a STT_GNU_IFUNC symbol we want the PLT address.
1874             if (gsym->type() == elfcpp::STT_GNU_IFUNC)
1875               got->add_global_plt(gsym, GOT_TYPE_STANDARD);
1876             else
1877               got->add_global(gsym, GOT_TYPE_STANDARD);
1878           }
1879         else
1880           {
1881             // If this symbol is not fully resolved, we need to add a
1882             // dynamic relocation for it.
1883             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1884             if (gsym->is_from_dynobj()
1885                 || gsym->is_undefined()
1886                 || gsym->is_preemptible()
1887                 || (gsym->type() == elfcpp::STT_GNU_IFUNC
1888                     && parameters->options().output_is_position_independent()))
1889               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1890                                         elfcpp::R_X86_64_GLOB_DAT);
1891             else
1892               {
1893                 // For a STT_GNU_IFUNC symbol we want to write the PLT
1894                 // offset into the GOT, so that function pointer
1895                 // comparisons work correctly.
1896                 bool is_new;
1897                 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
1898                   is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
1899                 else
1900                   {
1901                     is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
1902                     // Tell the dynamic linker to use the PLT address
1903                     // when resolving relocations.
1904                     if (gsym->is_from_dynobj()
1905                         && !parameters->options().shared())
1906                       gsym->set_needs_dynsym_value();
1907                   }
1908                 if (is_new)
1909                   {
1910                     unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
1911                     rela_dyn->add_global_relative(gsym,
1912                                                   elfcpp::R_X86_64_RELATIVE,
1913                                                   got, got_off, 0);
1914                   }
1915               }
1916           }
1917         // For GOTPLT64, we also need a PLT entry (but only if the
1918         // symbol is not fully resolved).
1919         if (r_type == elfcpp::R_X86_64_GOTPLT64
1920             && !gsym->final_value_is_known())
1921           target->make_plt_entry(symtab, layout, gsym);
1922       }
1923       break;
1924
1925     case elfcpp::R_X86_64_PLT32:
1926       // If the symbol is fully resolved, this is just a PC32 reloc.
1927       // Otherwise we need a PLT entry.
1928       if (gsym->final_value_is_known())
1929         break;
1930       // If building a shared library, we can also skip the PLT entry
1931       // if the symbol is defined in the output file and is protected
1932       // or hidden.
1933       if (gsym->is_defined()
1934           && !gsym->is_from_dynobj()
1935           && !gsym->is_preemptible())
1936         break;
1937       target->make_plt_entry(symtab, layout, gsym);
1938       break;
1939
1940     case elfcpp::R_X86_64_GOTPC32:
1941     case elfcpp::R_X86_64_GOTOFF64:
1942     case elfcpp::R_X86_64_GOTPC64:
1943     case elfcpp::R_X86_64_PLTOFF64:
1944       // We need a GOT section.
1945       target->got_section(symtab, layout);
1946       // For PLTOFF64, we also need a PLT entry (but only if the
1947       // symbol is not fully resolved).
1948       if (r_type == elfcpp::R_X86_64_PLTOFF64
1949           && !gsym->final_value_is_known())
1950         target->make_plt_entry(symtab, layout, gsym);
1951       break;
1952
1953     case elfcpp::R_X86_64_COPY:
1954     case elfcpp::R_X86_64_GLOB_DAT:
1955     case elfcpp::R_X86_64_JUMP_SLOT:
1956     case elfcpp::R_X86_64_RELATIVE:
1957     case elfcpp::R_X86_64_IRELATIVE:
1958       // These are outstanding tls relocs, which are unexpected when linking
1959     case elfcpp::R_X86_64_TPOFF64:
1960     case elfcpp::R_X86_64_DTPMOD64:
1961     case elfcpp::R_X86_64_TLSDESC:
1962       gold_error(_("%s: unexpected reloc %u in object file"),
1963                  object->name().c_str(), r_type);
1964       break;
1965
1966       // These are initial tls relocs, which are expected for global()
1967     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1968     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1969     case elfcpp::R_X86_64_TLSDESC_CALL:
1970     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1971     case elfcpp::R_X86_64_DTPOFF32:
1972     case elfcpp::R_X86_64_DTPOFF64:
1973     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1974     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1975       {
1976         const bool is_final = gsym->final_value_is_known();
1977         const tls::Tls_optimization optimized_type
1978             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1979         switch (r_type)
1980           {
1981           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1982             if (optimized_type == tls::TLSOPT_NONE)
1983               {
1984                 // Create a pair of GOT entries for the module index and
1985                 // dtv-relative offset.
1986                 Output_data_got<64, false>* got
1987                     = target->got_section(symtab, layout);
1988                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1989                                                target->rela_dyn_section(layout),
1990                                                elfcpp::R_X86_64_DTPMOD64,
1991                                                elfcpp::R_X86_64_DTPOFF64);
1992               }
1993             else if (optimized_type == tls::TLSOPT_TO_IE)
1994               {
1995                 // Create a GOT entry for the tp-relative offset.
1996                 Output_data_got<64, false>* got
1997                     = target->got_section(symtab, layout);
1998                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1999                                           target->rela_dyn_section(layout),
2000                                           elfcpp::R_X86_64_TPOFF64);
2001               }
2002             else if (optimized_type != tls::TLSOPT_TO_LE)
2003               unsupported_reloc_global(object, r_type, gsym);
2004             break;
2005
2006           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2007             target->define_tls_base_symbol(symtab, layout);
2008             if (optimized_type == tls::TLSOPT_NONE)
2009               {
2010                 // Create reserved PLT and GOT entries for the resolver.
2011                 target->reserve_tlsdesc_entries(symtab, layout);
2012
2013                 // Create a double GOT entry with an R_X86_64_TLSDESC
2014                 // reloc.  The R_X86_64_TLSDESC reloc is resolved
2015                 // lazily, so the GOT entry needs to be in an area in
2016                 // .got.plt, not .got.  Call got_section to make sure
2017                 // the section has been created.
2018                 target->got_section(symtab, layout);
2019                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2020                 Reloc_section *rt = target->rela_tlsdesc_section(layout);
2021                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
2022                                                elfcpp::R_X86_64_TLSDESC, 0);
2023               }
2024             else if (optimized_type == tls::TLSOPT_TO_IE)
2025               {
2026                 // Create a GOT entry for the tp-relative offset.
2027                 Output_data_got<64, false>* got
2028                     = target->got_section(symtab, layout);
2029                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2030                                           target->rela_dyn_section(layout),
2031                                           elfcpp::R_X86_64_TPOFF64);
2032               }
2033             else if (optimized_type != tls::TLSOPT_TO_LE)
2034               unsupported_reloc_global(object, r_type, gsym);
2035             break;
2036
2037           case elfcpp::R_X86_64_TLSDESC_CALL:
2038             break;
2039
2040           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
2041             if (optimized_type == tls::TLSOPT_NONE)
2042               {
2043                 // Create a GOT entry for the module index.
2044                 target->got_mod_index_entry(symtab, layout, object);
2045               }
2046             else if (optimized_type != tls::TLSOPT_TO_LE)
2047               unsupported_reloc_global(object, r_type, gsym);
2048             break;
2049
2050           case elfcpp::R_X86_64_DTPOFF32:
2051           case elfcpp::R_X86_64_DTPOFF64:
2052             break;
2053
2054           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
2055             layout->set_has_static_tls();
2056             if (optimized_type == tls::TLSOPT_NONE)
2057               {
2058                 // Create a GOT entry for the tp-relative offset.
2059                 Output_data_got<64, false>* got
2060                     = target->got_section(symtab, layout);
2061                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
2062                                           target->rela_dyn_section(layout),
2063                                           elfcpp::R_X86_64_TPOFF64);
2064               }
2065             else if (optimized_type != tls::TLSOPT_TO_LE)
2066               unsupported_reloc_global(object, r_type, gsym);
2067             break;
2068
2069           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
2070             layout->set_has_static_tls();
2071             if (parameters->options().shared())
2072               unsupported_reloc_local(object, r_type);
2073             break;
2074
2075           default:
2076             gold_unreachable();
2077           }
2078       }
2079       break;
2080
2081     case elfcpp::R_X86_64_SIZE32:
2082     case elfcpp::R_X86_64_SIZE64:
2083     default:
2084       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2085                  object->name().c_str(), r_type,
2086                  gsym->demangled_name().c_str());
2087       break;
2088     }
2089 }
2090
2091 void
2092 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
2093                                  Layout* layout,
2094                                  Sized_relobj<64, false>* object,
2095                                  unsigned int data_shndx,
2096                                  unsigned int sh_type,
2097                                  const unsigned char* prelocs,
2098                                  size_t reloc_count,
2099                                  Output_section* output_section,
2100                                  bool needs_special_offset_handling,
2101                                  size_t local_symbol_count,
2102                                  const unsigned char* plocal_symbols)
2103 {
2104
2105   if (sh_type == elfcpp::SHT_REL)
2106     {
2107       return;
2108     }
2109
2110    gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2111                            Target_x86_64::Scan,
2112                            Target_x86_64::Relocatable_size_for_reloc>(
2113     symtab,
2114     layout,
2115     this,
2116     object,
2117     data_shndx,
2118     prelocs,
2119     reloc_count,
2120     output_section,
2121     needs_special_offset_handling,
2122     local_symbol_count,
2123     plocal_symbols);
2124
2125 }
2126 // Scan relocations for a section.
2127
2128 void
2129 Target_x86_64::scan_relocs(Symbol_table* symtab,
2130                            Layout* layout,
2131                            Sized_relobj<64, false>* object,
2132                            unsigned int data_shndx,
2133                            unsigned int sh_type,
2134                            const unsigned char* prelocs,
2135                            size_t reloc_count,
2136                            Output_section* output_section,
2137                            bool needs_special_offset_handling,
2138                            size_t local_symbol_count,
2139                            const unsigned char* plocal_symbols)
2140 {
2141   if (sh_type == elfcpp::SHT_REL)
2142     {
2143       gold_error(_("%s: unsupported REL reloc section"),
2144                  object->name().c_str());
2145       return;
2146     }
2147
2148   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
2149       Target_x86_64::Scan>(
2150     symtab,
2151     layout,
2152     this,
2153     object,
2154     data_shndx,
2155     prelocs,
2156     reloc_count,
2157     output_section,
2158     needs_special_offset_handling,
2159     local_symbol_count,
2160     plocal_symbols);
2161 }
2162
2163 // Finalize the sections.
2164
2165 void
2166 Target_x86_64::do_finalize_sections(
2167     Layout* layout,
2168     const Input_objects*,
2169     Symbol_table* symtab)
2170 {
2171   const Reloc_section* rel_plt = (this->plt_ == NULL
2172                                   ? NULL
2173                                   : this->plt_->rela_plt());
2174   layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
2175                                   this->rela_dyn_, true, false);
2176
2177   // Fill in some more dynamic tags.
2178   Output_data_dynamic* const odyn = layout->dynamic_data();
2179   if (odyn != NULL)
2180     {
2181       if (this->plt_ != NULL
2182           && this->plt_->output_section() != NULL
2183           && this->plt_->has_tlsdesc_entry())
2184         {
2185           unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
2186           unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
2187           this->got_->finalize_data_size();
2188           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
2189                                         this->plt_, plt_offset);
2190           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
2191                                         this->got_, got_offset);
2192         }
2193     }
2194
2195   // Emit any relocs we saved in an attempt to avoid generating COPY
2196   // relocs.
2197   if (this->copy_relocs_.any_saved_relocs())
2198     this->copy_relocs_.emit(this->rela_dyn_section(layout));
2199
2200   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2201   // the .got.plt section.
2202   Symbol* sym = this->global_offset_table_;
2203   if (sym != NULL)
2204     {
2205       uint64_t data_size = this->got_plt_->current_data_size();
2206       symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
2207     }
2208 }
2209
2210 // Perform a relocation.
2211
2212 inline bool
2213 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
2214                                   Target_x86_64* target,
2215                                   Output_section*,
2216                                   size_t relnum,
2217                                   const elfcpp::Rela<64, false>& rela,
2218                                   unsigned int r_type,
2219                                   const Sized_symbol<64>* gsym,
2220                                   const Symbol_value<64>* psymval,
2221                                   unsigned char* view,
2222                                   elfcpp::Elf_types<64>::Elf_Addr address,
2223                                   section_size_type view_size)
2224 {
2225   if (this->skip_call_tls_get_addr_)
2226     {
2227       if ((r_type != elfcpp::R_X86_64_PLT32
2228            && r_type != elfcpp::R_X86_64_PC32)
2229           || gsym == NULL
2230           || strcmp(gsym->name(), "__tls_get_addr") != 0)
2231         {
2232           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2233                                  _("missing expected TLS relocation"));
2234         }
2235       else
2236         {
2237           this->skip_call_tls_get_addr_ = false;
2238           return false;
2239         }
2240     }
2241
2242   const Sized_relobj<64, false>* object = relinfo->object;
2243
2244   // Pick the value to use for symbols defined in the PLT.
2245   Symbol_value<64> symval;
2246   if (gsym != NULL
2247       && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
2248                               || r_type == elfcpp::R_X86_64_PC32
2249                               || r_type == elfcpp::R_X86_64_PC16
2250                               || r_type == elfcpp::R_X86_64_PC8))
2251     {
2252       symval.set_output_value(target->plt_section()->address()
2253                               + gsym->plt_offset());
2254       psymval = &symval;
2255     }
2256   else if (gsym == NULL && psymval->is_ifunc_symbol())
2257     {
2258       unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2259       if (object->local_has_plt_offset(r_sym))
2260         {
2261           symval.set_output_value(target->plt_section()->address()
2262                                   + object->local_plt_offset(r_sym));
2263           psymval = &symval;
2264         }
2265     }
2266
2267   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2268
2269   // Get the GOT offset if needed.
2270   // The GOT pointer points to the end of the GOT section.
2271   // We need to subtract the size of the GOT section to get
2272   // the actual offset to use in the relocation.
2273   bool have_got_offset = false;
2274   unsigned int got_offset = 0;
2275   switch (r_type)
2276     {
2277     case elfcpp::R_X86_64_GOT32:
2278     case elfcpp::R_X86_64_GOT64:
2279     case elfcpp::R_X86_64_GOTPLT64:
2280     case elfcpp::R_X86_64_GOTPCREL:
2281     case elfcpp::R_X86_64_GOTPCREL64:
2282       if (gsym != NULL)
2283         {
2284           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2285           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
2286         }
2287       else
2288         {
2289           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2290           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2291           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2292                         - target->got_size());
2293         }
2294       have_got_offset = true;
2295       break;
2296
2297     default:
2298       break;
2299     }
2300
2301   switch (r_type)
2302     {
2303     case elfcpp::R_X86_64_NONE:
2304     case elfcpp::R_X86_64_GNU_VTINHERIT:
2305     case elfcpp::R_X86_64_GNU_VTENTRY:
2306       break;
2307
2308     case elfcpp::R_X86_64_64:
2309       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
2310       break;
2311
2312     case elfcpp::R_X86_64_PC64:
2313       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
2314                                               address);
2315       break;
2316
2317     case elfcpp::R_X86_64_32:
2318       // FIXME: we need to verify that value + addend fits into 32 bits:
2319       //    uint64_t x = value + addend;
2320       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2321       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2322       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2323       break;
2324
2325     case elfcpp::R_X86_64_32S:
2326       // FIXME: we need to verify that value + addend fits into 32 bits:
2327       //    int64_t x = value + addend;   // note this quantity is signed!
2328       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
2329       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2330       break;
2331
2332     case elfcpp::R_X86_64_PC32:
2333       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2334                                               address);
2335       break;
2336
2337     case elfcpp::R_X86_64_16:
2338       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2339       break;
2340
2341     case elfcpp::R_X86_64_PC16:
2342       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2343                                               address);
2344       break;
2345
2346     case elfcpp::R_X86_64_8:
2347       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2348       break;
2349
2350     case elfcpp::R_X86_64_PC8:
2351       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2352                                              address);
2353       break;
2354
2355     case elfcpp::R_X86_64_PLT32:
2356       gold_assert(gsym == NULL
2357                   || gsym->has_plt_offset()
2358                   || gsym->final_value_is_known()
2359                   || (gsym->is_defined()
2360                       && !gsym->is_from_dynobj()
2361                       && !gsym->is_preemptible()));
2362       // Note: while this code looks the same as for R_X86_64_PC32, it
2363       // behaves differently because psymval was set to point to
2364       // the PLT entry, rather than the symbol, in Scan::global().
2365       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2366                                               address);
2367       break;
2368
2369     case elfcpp::R_X86_64_PLTOFF64:
2370       {
2371         gold_assert(gsym);
2372         gold_assert(gsym->has_plt_offset()
2373                     || gsym->final_value_is_known());
2374         elfcpp::Elf_types<64>::Elf_Addr got_address;
2375         got_address = target->got_section(NULL, NULL)->address();
2376         Relocate_functions<64, false>::rela64(view, object, psymval,
2377                                               addend - got_address);
2378       }
2379
2380     case elfcpp::R_X86_64_GOT32:
2381       gold_assert(have_got_offset);
2382       Relocate_functions<64, false>::rela32(view, got_offset, addend);
2383       break;
2384
2385     case elfcpp::R_X86_64_GOTPC32:
2386       {
2387         gold_assert(gsym);
2388         elfcpp::Elf_types<64>::Elf_Addr value;
2389         value = target->got_plt_section()->address();
2390         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2391       }
2392       break;
2393
2394     case elfcpp::R_X86_64_GOT64:
2395       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2396       // Since we always add a PLT entry, this is equivalent.
2397     case elfcpp::R_X86_64_GOTPLT64:
2398       gold_assert(have_got_offset);
2399       Relocate_functions<64, false>::rela64(view, got_offset, addend);
2400       break;
2401
2402     case elfcpp::R_X86_64_GOTPC64:
2403       {
2404         gold_assert(gsym);
2405         elfcpp::Elf_types<64>::Elf_Addr value;
2406         value = target->got_plt_section()->address();
2407         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2408       }
2409       break;
2410
2411     case elfcpp::R_X86_64_GOTOFF64:
2412       {
2413         elfcpp::Elf_types<64>::Elf_Addr value;
2414         value = (psymval->value(object, 0)
2415                  - target->got_plt_section()->address());
2416         Relocate_functions<64, false>::rela64(view, value, addend);
2417       }
2418       break;
2419
2420     case elfcpp::R_X86_64_GOTPCREL:
2421       {
2422         gold_assert(have_got_offset);
2423         elfcpp::Elf_types<64>::Elf_Addr value;
2424         value = target->got_plt_section()->address() + got_offset;
2425         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2426       }
2427       break;
2428
2429     case elfcpp::R_X86_64_GOTPCREL64:
2430       {
2431         gold_assert(have_got_offset);
2432         elfcpp::Elf_types<64>::Elf_Addr value;
2433         value = target->got_plt_section()->address() + got_offset;
2434         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2435       }
2436       break;
2437
2438     case elfcpp::R_X86_64_COPY:
2439     case elfcpp::R_X86_64_GLOB_DAT:
2440     case elfcpp::R_X86_64_JUMP_SLOT:
2441     case elfcpp::R_X86_64_RELATIVE:
2442     case elfcpp::R_X86_64_IRELATIVE:
2443       // These are outstanding tls relocs, which are unexpected when linking
2444     case elfcpp::R_X86_64_TPOFF64:
2445     case elfcpp::R_X86_64_DTPMOD64:
2446     case elfcpp::R_X86_64_TLSDESC:
2447       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2448                              _("unexpected reloc %u in object file"),
2449                              r_type);
2450       break;
2451
2452       // These are initial tls relocs, which are expected when linking
2453     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2454     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2455     case elfcpp::R_X86_64_TLSDESC_CALL:
2456     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2457     case elfcpp::R_X86_64_DTPOFF32:
2458     case elfcpp::R_X86_64_DTPOFF64:
2459     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2460     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2461       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
2462                          view, address, view_size);
2463       break;
2464
2465     case elfcpp::R_X86_64_SIZE32:
2466     case elfcpp::R_X86_64_SIZE64:
2467     default:
2468       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2469                              _("unsupported reloc %u"),
2470                              r_type);
2471       break;
2472     }
2473
2474   return true;
2475 }
2476
2477 // Perform a TLS relocation.
2478
2479 inline void
2480 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
2481                                       Target_x86_64* target,
2482                                       size_t relnum,
2483                                       const elfcpp::Rela<64, false>& rela,
2484                                       unsigned int r_type,
2485                                       const Sized_symbol<64>* gsym,
2486                                       const Symbol_value<64>* psymval,
2487                                       unsigned char* view,
2488                                       elfcpp::Elf_types<64>::Elf_Addr address,
2489                                       section_size_type view_size)
2490 {
2491   Output_segment* tls_segment = relinfo->layout->tls_segment();
2492
2493   const Sized_relobj<64, false>* object = relinfo->object;
2494   const elfcpp::Elf_Xword addend = rela.get_r_addend();
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   const 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       this->saw_tls_block_reloc_ = true;
2507       if (optimized_type == tls::TLSOPT_TO_LE)
2508         {
2509           gold_assert(tls_segment != NULL);
2510           this->tls_gd_to_le(relinfo, relnum, tls_segment,
2511                              rela, r_type, value, view,
2512                              view_size);
2513           break;
2514         }
2515       else
2516         {
2517           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2518                                    ? GOT_TYPE_TLS_OFFSET
2519                                    : GOT_TYPE_TLS_PAIR);
2520           unsigned int got_offset;
2521           if (gsym != NULL)
2522             {
2523               gold_assert(gsym->has_got_offset(got_type));
2524               got_offset = gsym->got_offset(got_type) - target->got_size();
2525             }
2526           else
2527             {
2528               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2529               gold_assert(object->local_has_got_offset(r_sym, got_type));
2530               got_offset = (object->local_got_offset(r_sym, got_type)
2531                             - target->got_size());
2532             }
2533           if (optimized_type == tls::TLSOPT_TO_IE)
2534             {
2535               gold_assert(tls_segment != NULL);
2536               value = target->got_plt_section()->address() + got_offset;
2537               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2538                                  value, view, address, view_size);
2539               break;
2540             }
2541           else if (optimized_type == tls::TLSOPT_NONE)
2542             {
2543               // Relocate the field with the offset of the pair of GOT
2544               // entries.
2545               value = target->got_plt_section()->address() + got_offset;
2546               Relocate_functions<64, false>::pcrela32(view, value, addend,
2547                                                       address);
2548               break;
2549             }
2550         }
2551       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2552                              _("unsupported reloc %u"), r_type);
2553       break;
2554
2555     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2556     case elfcpp::R_X86_64_TLSDESC_CALL:
2557       this->saw_tls_block_reloc_ = true;
2558       if (optimized_type == tls::TLSOPT_TO_LE)
2559         {
2560           gold_assert(tls_segment != NULL);
2561           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2562                                   rela, r_type, value, view,
2563                                   view_size);
2564           break;
2565         }
2566       else
2567         {
2568           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2569                                    ? GOT_TYPE_TLS_OFFSET
2570                                    : GOT_TYPE_TLS_DESC);
2571           unsigned int got_offset = 0;
2572           if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
2573               && optimized_type == tls::TLSOPT_NONE)
2574             {
2575               // We created GOT entries in the .got.tlsdesc portion of
2576               // the .got.plt section, but the offset stored in the
2577               // symbol is the offset within .got.tlsdesc.
2578               got_offset = (target->got_size()
2579                             + target->got_plt_section()->data_size());
2580             }
2581           if (gsym != NULL)
2582             {
2583               gold_assert(gsym->has_got_offset(got_type));
2584               got_offset += gsym->got_offset(got_type) - target->got_size();
2585             }
2586           else
2587             {
2588               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2589               gold_assert(object->local_has_got_offset(r_sym, got_type));
2590               got_offset += (object->local_got_offset(r_sym, got_type)
2591                              - target->got_size());
2592             }
2593           if (optimized_type == tls::TLSOPT_TO_IE)
2594             {
2595               gold_assert(tls_segment != NULL);
2596               value = target->got_plt_section()->address() + got_offset;
2597               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2598                                       rela, r_type, value, view, address,
2599                                       view_size);
2600               break;
2601             }
2602           else if (optimized_type == tls::TLSOPT_NONE)
2603             {
2604               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2605                 {
2606                   // Relocate the field with the offset of the pair of GOT
2607                   // entries.
2608                   value = target->got_plt_section()->address() + got_offset;
2609                   Relocate_functions<64, false>::pcrela32(view, value, addend,
2610                                                           address);
2611                 }
2612               break;
2613             }
2614         }
2615       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2616                              _("unsupported reloc %u"), r_type);
2617       break;
2618
2619     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2620       this->saw_tls_block_reloc_ = true;
2621       if (optimized_type == tls::TLSOPT_TO_LE)
2622         {
2623           gold_assert(tls_segment != NULL);
2624           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2625                              value, view, view_size);
2626           break;
2627         }
2628       else if (optimized_type == tls::TLSOPT_NONE)
2629         {
2630           // Relocate the field with the offset of the GOT entry for
2631           // the module index.
2632           unsigned int got_offset;
2633           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2634                         - target->got_size());
2635           value = target->got_plt_section()->address() + got_offset;
2636           Relocate_functions<64, false>::pcrela32(view, value, addend,
2637                                                   address);
2638           break;
2639         }
2640       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2641                              _("unsupported reloc %u"), r_type);
2642       break;
2643
2644     case elfcpp::R_X86_64_DTPOFF32:
2645       if (optimized_type == tls::TLSOPT_TO_LE)
2646         {
2647           // This relocation type is used in debugging information.
2648           // In that case we need to not optimize the value.  If we
2649           // haven't seen a TLSLD reloc, then we assume we should not
2650           // optimize this reloc.
2651           if (this->saw_tls_block_reloc_)
2652             {
2653               gold_assert(tls_segment != NULL);
2654               value -= tls_segment->memsz();
2655             }
2656         }
2657       Relocate_functions<64, false>::rela32(view, value, addend);
2658       break;
2659
2660     case elfcpp::R_X86_64_DTPOFF64:
2661       if (optimized_type == tls::TLSOPT_TO_LE)
2662         {
2663           // See R_X86_64_DTPOFF32, just above, for why we test this.
2664           if (this->saw_tls_block_reloc_)
2665             {
2666               gold_assert(tls_segment != NULL);
2667               value -= tls_segment->memsz();
2668             }
2669         }
2670       Relocate_functions<64, false>::rela64(view, value, addend);
2671       break;
2672
2673     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2674       if (optimized_type == tls::TLSOPT_TO_LE)
2675         {
2676           gold_assert(tls_segment != NULL);
2677           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2678                                                 rela, r_type, value, view,
2679                                                 view_size);
2680           break;
2681         }
2682       else if (optimized_type == tls::TLSOPT_NONE)
2683         {
2684           // Relocate the field with the offset of the GOT entry for
2685           // the tp-relative offset of the symbol.
2686           unsigned int got_offset;
2687           if (gsym != NULL)
2688             {
2689               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2690               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2691                             - target->got_size());
2692             }
2693           else
2694             {
2695               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2696               gold_assert(object->local_has_got_offset(r_sym,
2697                                                        GOT_TYPE_TLS_OFFSET));
2698               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2699                             - target->got_size());
2700             }
2701           value = target->got_plt_section()->address() + got_offset;
2702           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2703           break;
2704         }
2705       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2706                              _("unsupported reloc type %u"),
2707                              r_type);
2708       break;
2709
2710     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2711       value -= tls_segment->memsz();
2712       Relocate_functions<64, false>::rela32(view, value, addend);
2713       break;
2714     }
2715 }
2716
2717 // Do a relocation in which we convert a TLS General-Dynamic to an
2718 // Initial-Exec.
2719
2720 inline void
2721 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2722                                       size_t relnum,
2723                                       Output_segment*,
2724                                       const elfcpp::Rela<64, false>& rela,
2725                                       unsigned int,
2726                                       elfcpp::Elf_types<64>::Elf_Addr value,
2727                                       unsigned char* view,
2728                                       elfcpp::Elf_types<64>::Elf_Addr address,
2729                                       section_size_type view_size)
2730 {
2731   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2732   // .word 0x6666; rex64; call __tls_get_addr
2733   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2734
2735   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2736   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2737
2738   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2739                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2740   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2741                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2742
2743   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2744
2745   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2746   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2747
2748   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2749   // We can skip it.
2750   this->skip_call_tls_get_addr_ = true;
2751 }
2752
2753 // Do a relocation in which we convert a TLS General-Dynamic to a
2754 // Local-Exec.
2755
2756 inline void
2757 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2758                                       size_t relnum,
2759                                       Output_segment* tls_segment,
2760                                       const elfcpp::Rela<64, false>& rela,
2761                                       unsigned int,
2762                                       elfcpp::Elf_types<64>::Elf_Addr value,
2763                                       unsigned char* view,
2764                                       section_size_type view_size)
2765 {
2766   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2767   // .word 0x6666; rex64; call __tls_get_addr
2768   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2769
2770   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2771   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2772
2773   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2774                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2775   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2776                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2777
2778   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2779
2780   value -= tls_segment->memsz();
2781   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2782
2783   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2784   // We can skip it.
2785   this->skip_call_tls_get_addr_ = true;
2786 }
2787
2788 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2789
2790 inline void
2791 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2792     const Relocate_info<64, false>* relinfo,
2793     size_t relnum,
2794     Output_segment*,
2795     const elfcpp::Rela<64, false>& rela,
2796     unsigned int r_type,
2797     elfcpp::Elf_types<64>::Elf_Addr value,
2798     unsigned char* view,
2799     elfcpp::Elf_types<64>::Elf_Addr address,
2800     section_size_type view_size)
2801 {
2802   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2803     {
2804       // leaq foo@tlsdesc(%rip), %rax
2805       // ==> movq foo@gottpoff(%rip), %rax
2806       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2807       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2808       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2809                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2810       view[-2] = 0x8b;
2811       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2812       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2813     }
2814   else
2815     {
2816       // call *foo@tlscall(%rax)
2817       // ==> nop; nop
2818       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2819       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2820       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2821                      view[0] == 0xff && view[1] == 0x10);
2822       view[0] = 0x66;
2823       view[1] = 0x90;
2824     }
2825 }
2826
2827 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2828
2829 inline void
2830 Target_x86_64::Relocate::tls_desc_gd_to_le(
2831     const Relocate_info<64, false>* relinfo,
2832     size_t relnum,
2833     Output_segment* tls_segment,
2834     const elfcpp::Rela<64, false>& rela,
2835     unsigned int r_type,
2836     elfcpp::Elf_types<64>::Elf_Addr value,
2837     unsigned char* view,
2838     section_size_type view_size)
2839 {
2840   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2841     {
2842       // leaq foo@tlsdesc(%rip), %rax
2843       // ==> movq foo@tpoff, %rax
2844       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2845       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2846       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2847                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2848       view[-2] = 0xc7;
2849       view[-1] = 0xc0;
2850       value -= tls_segment->memsz();
2851       Relocate_functions<64, false>::rela32(view, value, 0);
2852     }
2853   else
2854     {
2855       // call *foo@tlscall(%rax)
2856       // ==> nop; nop
2857       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2858       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2859       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2860                      view[0] == 0xff && view[1] == 0x10);
2861       view[0] = 0x66;
2862       view[1] = 0x90;
2863     }
2864 }
2865
2866 inline void
2867 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2868                                       size_t relnum,
2869                                       Output_segment*,
2870                                       const elfcpp::Rela<64, false>& rela,
2871                                       unsigned int,
2872                                       elfcpp::Elf_types<64>::Elf_Addr,
2873                                       unsigned char* view,
2874                                       section_size_type view_size)
2875 {
2876   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2877   // ... leq foo@dtpoff(%rax),%reg
2878   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2879
2880   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2881   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2882
2883   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2884                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2885
2886   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2887
2888   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2889
2890   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2891   // We can skip it.
2892   this->skip_call_tls_get_addr_ = true;
2893 }
2894
2895 // Do a relocation in which we convert a TLS Initial-Exec to a
2896 // Local-Exec.
2897
2898 inline void
2899 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2900                                       size_t relnum,
2901                                       Output_segment* tls_segment,
2902                                       const elfcpp::Rela<64, false>& rela,
2903                                       unsigned int,
2904                                       elfcpp::Elf_types<64>::Elf_Addr value,
2905                                       unsigned char* view,
2906                                       section_size_type view_size)
2907 {
2908   // We need to examine the opcodes to figure out which instruction we
2909   // are looking at.
2910
2911   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2912   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2913
2914   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2915   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2916
2917   unsigned char op1 = view[-3];
2918   unsigned char op2 = view[-2];
2919   unsigned char op3 = view[-1];
2920   unsigned char reg = op3 >> 3;
2921
2922   if (op2 == 0x8b)
2923     {
2924       // movq
2925       if (op1 == 0x4c)
2926         view[-3] = 0x49;
2927       view[-2] = 0xc7;
2928       view[-1] = 0xc0 | reg;
2929     }
2930   else if (reg == 4)
2931     {
2932       // Special handling for %rsp.
2933       if (op1 == 0x4c)
2934         view[-3] = 0x49;
2935       view[-2] = 0x81;
2936       view[-1] = 0xc0 | reg;
2937     }
2938   else
2939     {
2940       // addq
2941       if (op1 == 0x4c)
2942         view[-3] = 0x4d;
2943       view[-2] = 0x8d;
2944       view[-1] = 0x80 | reg | (reg << 3);
2945     }
2946
2947   value -= tls_segment->memsz();
2948   Relocate_functions<64, false>::rela32(view, value, 0);
2949 }
2950
2951 // Relocate section data.
2952
2953 void
2954 Target_x86_64::relocate_section(
2955     const Relocate_info<64, false>* relinfo,
2956     unsigned int sh_type,
2957     const unsigned char* prelocs,
2958     size_t reloc_count,
2959     Output_section* output_section,
2960     bool needs_special_offset_handling,
2961     unsigned char* view,
2962     elfcpp::Elf_types<64>::Elf_Addr address,
2963     section_size_type view_size,
2964     const Reloc_symbol_changes* reloc_symbol_changes)
2965 {
2966   gold_assert(sh_type == elfcpp::SHT_RELA);
2967
2968   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2969                          Target_x86_64::Relocate>(
2970     relinfo,
2971     this,
2972     prelocs,
2973     reloc_count,
2974     output_section,
2975     needs_special_offset_handling,
2976     view,
2977     address,
2978     view_size,
2979     reloc_symbol_changes);
2980 }
2981
2982 // Return the size of a relocation while scanning during a relocatable
2983 // link.
2984
2985 unsigned int
2986 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2987     unsigned int r_type,
2988     Relobj* object)
2989 {
2990   switch (r_type)
2991     {
2992     case elfcpp::R_X86_64_NONE:
2993     case elfcpp::R_X86_64_GNU_VTINHERIT:
2994     case elfcpp::R_X86_64_GNU_VTENTRY:
2995     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2996     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2997     case elfcpp::R_X86_64_TLSDESC_CALL:
2998     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2999     case elfcpp::R_X86_64_DTPOFF32:
3000     case elfcpp::R_X86_64_DTPOFF64:
3001     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
3002     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
3003       return 0;
3004
3005     case elfcpp::R_X86_64_64:
3006     case elfcpp::R_X86_64_PC64:
3007     case elfcpp::R_X86_64_GOTOFF64:
3008     case elfcpp::R_X86_64_GOTPC64:
3009     case elfcpp::R_X86_64_PLTOFF64:
3010     case elfcpp::R_X86_64_GOT64:
3011     case elfcpp::R_X86_64_GOTPCREL64:
3012     case elfcpp::R_X86_64_GOTPCREL:
3013     case elfcpp::R_X86_64_GOTPLT64:
3014       return 8;
3015
3016     case elfcpp::R_X86_64_32:
3017     case elfcpp::R_X86_64_32S:
3018     case elfcpp::R_X86_64_PC32:
3019     case elfcpp::R_X86_64_PLT32:
3020     case elfcpp::R_X86_64_GOTPC32:
3021     case elfcpp::R_X86_64_GOT32:
3022       return 4;
3023
3024     case elfcpp::R_X86_64_16:
3025     case elfcpp::R_X86_64_PC16:
3026       return 2;
3027
3028     case elfcpp::R_X86_64_8:
3029     case elfcpp::R_X86_64_PC8:
3030       return 1;
3031
3032     case elfcpp::R_X86_64_COPY:
3033     case elfcpp::R_X86_64_GLOB_DAT:
3034     case elfcpp::R_X86_64_JUMP_SLOT:
3035     case elfcpp::R_X86_64_RELATIVE:
3036     case elfcpp::R_X86_64_IRELATIVE:
3037       // These are outstanding tls relocs, which are unexpected when linking
3038     case elfcpp::R_X86_64_TPOFF64:
3039     case elfcpp::R_X86_64_DTPMOD64:
3040     case elfcpp::R_X86_64_TLSDESC:
3041       object->error(_("unexpected reloc %u in object file"), r_type);
3042       return 0;
3043
3044     case elfcpp::R_X86_64_SIZE32:
3045     case elfcpp::R_X86_64_SIZE64:
3046     default:
3047       object->error(_("unsupported reloc %u against local symbol"), r_type);
3048       return 0;
3049     }
3050 }
3051
3052 // Scan the relocs during a relocatable link.
3053
3054 void
3055 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
3056                                        Layout* layout,
3057                                        Sized_relobj<64, false>* object,
3058                                        unsigned int data_shndx,
3059                                        unsigned int sh_type,
3060                                        const unsigned char* prelocs,
3061                                        size_t reloc_count,
3062                                        Output_section* output_section,
3063                                        bool needs_special_offset_handling,
3064                                        size_t local_symbol_count,
3065                                        const unsigned char* plocal_symbols,
3066                                        Relocatable_relocs* rr)
3067 {
3068   gold_assert(sh_type == elfcpp::SHT_RELA);
3069
3070   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
3071     Relocatable_size_for_reloc> Scan_relocatable_relocs;
3072
3073   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
3074       Scan_relocatable_relocs>(
3075     symtab,
3076     layout,
3077     object,
3078     data_shndx,
3079     prelocs,
3080     reloc_count,
3081     output_section,
3082     needs_special_offset_handling,
3083     local_symbol_count,
3084     plocal_symbols,
3085     rr);
3086 }
3087
3088 // Relocate a section during a relocatable link.
3089
3090 void
3091 Target_x86_64::relocate_for_relocatable(
3092     const Relocate_info<64, false>* relinfo,
3093     unsigned int sh_type,
3094     const unsigned char* prelocs,
3095     size_t reloc_count,
3096     Output_section* output_section,
3097     off_t offset_in_output_section,
3098     const Relocatable_relocs* rr,
3099     unsigned char* view,
3100     elfcpp::Elf_types<64>::Elf_Addr view_address,
3101     section_size_type view_size,
3102     unsigned char* reloc_view,
3103     section_size_type reloc_view_size)
3104 {
3105   gold_assert(sh_type == elfcpp::SHT_RELA);
3106
3107   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
3108     relinfo,
3109     prelocs,
3110     reloc_count,
3111     output_section,
3112     offset_in_output_section,
3113     rr,
3114     view,
3115     view_address,
3116     view_size,
3117     reloc_view,
3118     reloc_view_size);
3119 }
3120
3121 // Return the value to use for a dynamic which requires special
3122 // treatment.  This is how we support equality comparisons of function
3123 // pointers across shared library boundaries, as described in the
3124 // processor specific ABI supplement.
3125
3126 uint64_t
3127 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
3128 {
3129   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
3130   return this->plt_section()->address() + gsym->plt_offset();
3131 }
3132
3133 // Return a string used to fill a code section with nops to take up
3134 // the specified length.
3135
3136 std::string
3137 Target_x86_64::do_code_fill(section_size_type length) const
3138 {
3139   if (length >= 16)
3140     {
3141       // Build a jmpq instruction to skip over the bytes.
3142       unsigned char jmp[5];
3143       jmp[0] = 0xe9;
3144       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
3145       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
3146               + std::string(length - 5, '\0'));
3147     }
3148
3149   // Nop sequences of various lengths.
3150   const char nop1[1] = { 0x90 };                   // nop
3151   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
3152   const char nop3[3] = { 0x0f, 0x1f, 0x00 };       // nop (%rax)
3153   const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00};  // nop 0(%rax)
3154   const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00,   // nop 0(%rax,%rax,1)
3155                          0x00 };
3156   const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44,   // nopw 0(%rax,%rax,1)
3157                          0x00, 0x00 };
3158   const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00,   // nopl 0L(%rax)
3159                          0x00, 0x00, 0x00 };
3160   const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00,   // nopl 0L(%rax,%rax,1)
3161                          0x00, 0x00, 0x00, 0x00 };
3162   const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84,   // nopw 0L(%rax,%rax,1)
3163                          0x00, 0x00, 0x00, 0x00,
3164                          0x00 };
3165   const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
3166                            0x84, 0x00, 0x00, 0x00,
3167                            0x00, 0x00 };
3168   const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
3169                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3170                            0x00, 0x00, 0x00 };
3171   const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
3172                            0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
3173                            0x00, 0x00, 0x00, 0x00 };
3174   const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3175                            0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
3176                            0x00, 0x00, 0x00, 0x00,
3177                            0x00 };
3178   const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3179                            0x66, 0x2e, 0x0f, 0x1f, // data16
3180                            0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3181                            0x00, 0x00 };
3182   const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
3183                            0x66, 0x66, 0x2e, 0x0f, // data16; data16
3184                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
3185                            0x00, 0x00, 0x00 };
3186
3187   const char* nops[16] = {
3188     NULL,
3189     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
3190     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
3191   };
3192
3193   return std::string(nops[length], length);
3194 }
3195
3196 // Return the addend to use for a target specific relocation.  The
3197 // only target specific relocation is R_X86_64_TLSDESC for a local
3198 // symbol.  We want to set the addend is the offset of the local
3199 // symbol in the TLS segment.
3200
3201 uint64_t
3202 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
3203                                uint64_t) const
3204 {
3205   gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
3206   uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
3207   gold_assert(intarg < this->tlsdesc_reloc_info_.size());
3208   const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
3209   const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
3210   gold_assert(psymval->is_tls_symbol());
3211   // The value of a TLS symbol is the offset in the TLS segment.
3212   return psymval->value(ti.object, 0);
3213 }
3214
3215 // FNOFFSET in section SHNDX in OBJECT is the start of a function
3216 // compiled with -fstack-split.  The function calls non-stack-split
3217 // code.  We have to change the function so that it always ensures
3218 // that it has enough stack space to run some random function.
3219
3220 void
3221 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
3222                                   section_offset_type fnoffset,
3223                                   section_size_type fnsize,
3224                                   unsigned char* view,
3225                                   section_size_type view_size,
3226                                   std::string* from,
3227                                   std::string* to) const
3228 {
3229   // The function starts with a comparison of the stack pointer and a
3230   // field in the TCB.  This is followed by a jump.
3231
3232   // cmp %fs:NN,%rsp
3233   if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
3234       && fnsize > 9)
3235     {
3236       // We will call __morestack if the carry flag is set after this
3237       // comparison.  We turn the comparison into an stc instruction
3238       // and some nops.
3239       view[fnoffset] = '\xf9';
3240       this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
3241     }
3242   // lea NN(%rsp),%r10
3243   // lea NN(%rsp),%r11
3244   else if ((this->match_view(view, view_size, fnoffset,
3245                              "\x4c\x8d\x94\x24", 4)
3246             || this->match_view(view, view_size, fnoffset,
3247                                 "\x4c\x8d\x9c\x24", 4))
3248            && fnsize > 8)
3249     {
3250       // This is loading an offset from the stack pointer for a
3251       // comparison.  The offset is negative, so we decrease the
3252       // offset by the amount of space we need for the stack.  This
3253       // means we will avoid calling __morestack if there happens to
3254       // be plenty of space on the stack already.
3255       unsigned char* pval = view + fnoffset + 4;
3256       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3257       val -= parameters->options().split_stack_adjust_size();
3258       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3259     }
3260   else
3261     {
3262       if (!object->has_no_split_stack())
3263         object->error(_("failed to match split-stack sequence at "
3264                         "section %u offset %0zx"),
3265                       shndx, static_cast<size_t>(fnoffset));
3266       return;
3267     }
3268
3269   // We have to change the function so that it calls
3270   // __morestack_non_split instead of __morestack.  The former will
3271   // allocate additional stack space.
3272   *from = "__morestack";
3273   *to = "__morestack_non_split";
3274 }
3275
3276 // The selector for x86_64 object files.
3277
3278 class Target_selector_x86_64 : public Target_selector_freebsd
3279 {
3280 public:
3281   Target_selector_x86_64()
3282     : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
3283                               "elf64-x86-64-freebsd")
3284   { }
3285
3286   Target*
3287   do_instantiate_target()
3288   { return new Target_x86_64(); }
3289
3290 };
3291
3292 Target_selector_x86_64 target_selector_x86_64;
3293
3294 } // End anonymous namespace.