gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 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
   9 // modify it under the terms of the GNU Library General Public License
  10 // as published by the Free Software Foundation; either version 2, or
  11 // (at your option) any later version.
  12
  13 // In addition to the permissions in the GNU Library General Public
  14 // License, the Free Software Foundation gives you unlimited
  15 // permission to link the compiled version of this file into
  16 // combinations with other programs, and to distribute those
  17 // combinations without any restriction coming from the use of this
  18 // file.  (The Library Public License restrictions do apply in other
  19 // respects; for example, they cover modification of the file, and
  20 /// distribution when not linked into a combined executable.)
  21
  22 // This program is distributed in the hope that it will be useful, but
  23 // WITHOUT ANY WARRANTY; without even the implied warranty of
  24 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  25 // Library General Public License for more details.
  26
  27 // You should have received a copy of the GNU Library General Public
  28 // License along with this program; if not, write to the Free Software
  29 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  30 // 02110-1301, USA.
  31
  32 #include "gold.h"
  33
  34 #include <cstring>
  35
  36 #include "elfcpp.h"
  37 #include "parameters.h"
  38 #include "reloc.h"
  39 #include "x86_64.h"
  40 #include "object.h"
  41 #include "symtab.h"
  42 #include "layout.h"
  43 #include "output.h"
  44 #include "target.h"
  45 #include "target-reloc.h"
  46 #include "target-select.h"
  47 #include "tls.h"
  48
  49 namespace
  50 {
  51
  52 using namespace gold;
  53
  54 class Output_data_plt_x86_64;
  55
  56 // The x86_64 target class.
  57 // See the ABI at
  58 //   http://www.x86-64.org/documentation/abi.pdf
  59 // TLS info comes from
  60 //   http://people.redhat.com/drepper/tls.pdf
  61 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  62
  63 class Target_x86_64 : public Sized_target<64, false>
  64 {
  65  public:
  66   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
  67   // uses only Elf64_Rela relocation entries with explicit addends."
  68   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  69
  70   Target_x86_64()
  71     : Sized_target<64, false>(&x86_64_info),
  72       got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
  73       copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
  74   { }
  75
  76   // Scan the relocations to look for symbol adjustments.
  77   void
  78   scan_relocs(const General_options& options,
  79               Symbol_table* symtab,
  80               Layout* layout,
  81               Sized_relobj<64, false>* object,
  82               unsigned int data_shndx,
  83               unsigned int sh_type,
  84               const unsigned char* prelocs,
  85               size_t reloc_count,
  86               Output_section* output_section,
  87               bool needs_special_offset_handling,
  88               size_t local_symbol_count,
  89               const unsigned char* plocal_symbols);
  90
  91   // Finalize the sections.
  92   void
  93   do_finalize_sections(Layout*);
  94
  95   // Return the value to use for a dynamic which requires special
  96   // treatment.
  97   uint64_t
  98   do_dynsym_value(const Symbol*) const;
  99
 100   // Relocate a section.
 101   void
 102   relocate_section(const Relocate_info<64, false>*,
 103                    unsigned int sh_type,
 104                    const unsigned char* prelocs,
 105                    size_t reloc_count,
 106                    Output_section* output_section,
 107                    bool needs_special_offset_handling,
 108                    unsigned char* view,
 109                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 110                    off_t view_size);
 111
 112   // Return a string used to fill a code section with nops.
 113   std::string
 114   do_code_fill(off_t length);
 115
 116   // Return whether SYM is defined by the ABI.
 117   bool
 118   do_is_defined_by_abi(Symbol* sym) const
 119   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 120
 121   // Return the size of the GOT section.
 122   off_t
 123   got_size()
 124   {
 125     gold_assert(this->got_ != NULL);
 126     return this->got_->data_size();
 127   }
 128
 129  private:
 130   // The class which scans relocations.
 131   struct Scan
 132   {
 133     inline void
 134     local(const General_options& options, Symbol_table* symtab,
 135           Layout* layout, Target_x86_64* target,
 136           Sized_relobj<64, false>* object,
 137           unsigned int data_shndx,
 138           Output_section* output_section,
 139           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 140           const elfcpp::Sym<64, false>& lsym);
 141
 142     inline void
 143     global(const General_options& options, Symbol_table* symtab,
 144            Layout* layout, Target_x86_64* target,
 145            Sized_relobj<64, false>* object,
 146            unsigned int data_shndx,
 147            Output_section* output_section,
 148            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 149            Symbol* gsym);
 150
 151     static void
 152     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 153
 154     static void
 155     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 156                              Symbol*);
 157   };
 158
 159   // The class which implements relocation.
 160   class Relocate
 161   {
 162    public:
 163     Relocate()
 164       : skip_call_tls_get_addr_(false)
 165     { }
 166
 167     ~Relocate()
 168     {
 169       if (this->skip_call_tls_get_addr_)
 170         {
 171           // FIXME: This needs to specify the location somehow.
 172           gold_error(_("missing expected TLS relocation"));
 173         }
 174     }
 175
 176     // Do a relocation.  Return false if the caller should not issue
 177     // any warnings about this relocation.
 178     inline bool
 179     relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum,
 180              const elfcpp::Rela<64, false>&,
 181              unsigned int r_type, const Sized_symbol<64>*,
 182              const Symbol_value<64>*,
 183              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 184              off_t);
 185
 186    private:
 187     // Do a TLS relocation.
 188     inline void
 189     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 190                  size_t relnum, const elfcpp::Rela<64, false>&,
 191                  unsigned int r_type, const Sized_symbol<64>*,
 192                  const Symbol_value<64>*,
 193                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, off_t);
 194
 195     // Do a TLS General-Dynamic to Local-Exec transition.
 196     inline void
 197     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 198                  Output_segment* tls_segment,
 199                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 200                  elfcpp::Elf_types<64>::Elf_Addr value,
 201                  unsigned char* view,
 202                  off_t view_size);
 203
 204     // Do a TLS General-Dynamic to Local-Exec transition.
 205     inline void
 206     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 207                  Output_segment* tls_segment,
 208                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 209                  elfcpp::Elf_types<64>::Elf_Addr value,
 210                  unsigned char* view,
 211                  off_t view_size);
 212
 213     // Do a TLS Local-Dynamic to Local-Exec transition.
 214     inline void
 215     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 216                  Output_segment* tls_segment,
 217                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 218                  elfcpp::Elf_types<64>::Elf_Addr value,
 219                  unsigned char* view,
 220                  off_t view_size);
 221
 222     // Do a TLS Initial-Exec to Local-Exec transition.
 223     static inline void
 224     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 225                  Output_segment* tls_segment,
 226                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 227                  elfcpp::Elf_types<64>::Elf_Addr value,
 228                  unsigned char* view,
 229                  off_t view_size);
 230
 231     // This is set if we should skip the next reloc, which should be a
 232     // PLT32 reloc against ___tls_get_addr.
 233     bool skip_call_tls_get_addr_;
 234   };
 235
 236   // Adjust TLS relocation type based on the options and whether this
 237   // is a local symbol.
 238   static tls::Tls_optimization
 239   optimize_tls_reloc(bool is_final, int r_type);
 240
 241   // Get the GOT section, creating it if necessary.
 242   Output_data_got<64, false>*
 243   got_section(Symbol_table*, Layout*);
 244
 245   // Get the GOT PLT section.
 246   Output_data_space*
 247   got_plt_section() const
 248   {
 249     gold_assert(this->got_plt_ != NULL);
 250     return this->got_plt_;
 251   }
 252
 253   // Create a PLT entry for a global symbol.
 254   void
 255   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 256
 257   // Create a GOT entry for the TLS module index.
 258   unsigned int
 259   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 260                       Sized_relobj<64, false>* object);
 261
 262   // Get the PLT section.
 263   Output_data_plt_x86_64*
 264   plt_section() const
 265   {
 266     gold_assert(this->plt_ != NULL);
 267     return this->plt_;
 268   }
 269
 270   // Get the dynamic reloc section, creating it if necessary.
 271   Reloc_section*
 272   rela_dyn_section(Layout*);
 273
 274   // Return true if the symbol may need a COPY relocation.
 275   // References from an executable object to non-function symbols
 276   // defined in a dynamic object may need a COPY relocation.
 277   bool
 278   may_need_copy_reloc(Symbol* gsym)
 279   {
 280     return (!parameters->output_is_shared()
 281             && gsym->is_from_dynobj()
 282             && gsym->type() != elfcpp::STT_FUNC);
 283   }
 284
 285   // Copy a relocation against a global symbol.
 286   void
 287   copy_reloc(const General_options*, Symbol_table*, Layout*,
 288              Sized_relobj<64, false>*, unsigned int,
 289              Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
 290
 291   // Information about this specific target which we pass to the
 292   // general Target structure.
 293   static const Target::Target_info x86_64_info;
 294
 295   // The GOT section.
 296   Output_data_got<64, false>* got_;
 297   // The PLT section.
 298   Output_data_plt_x86_64* plt_;
 299   // The GOT PLT section.
 300   Output_data_space* got_plt_;
 301   // The dynamic reloc section.
 302   Reloc_section* rela_dyn_;
 303   // Relocs saved to avoid a COPY reloc.
 304   Copy_relocs<64, false>* copy_relocs_;
 305   // Space for variables copied with a COPY reloc.
 306   Output_data_space* dynbss_;
 307   // Offset of the GOT entry for the TLS module index;
 308   unsigned int got_mod_index_offset_;
 309 };
 310
 311 const Target::Target_info Target_x86_64::x86_64_info =
 312 {
 313   64,                   // size
 314   false,                // is_big_endian
 315   elfcpp::EM_X86_64,    // machine_code
 316   false,                // has_make_symbol
 317   false,                // has_resolve
 318   true,                 // has_code_fill
 319   true,                 // is_default_stack_executable
 320   "/lib/ld64.so.1",     // program interpreter
 321   0x400000,             // default_text_segment_address
 322   0x1000,               // abi_pagesize
 323   0x1000                // common_pagesize
 324 };
 325
 326 // Get the GOT section, creating it if necessary.
 327
 328 Output_data_got<64, false>*
 329 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 330 {
 331   if (this->got_ == NULL)
 332     {
 333       gold_assert(symtab != NULL && layout != NULL);
 334
 335       this->got_ = new Output_data_got<64, false>();
 336
 337       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 338                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 339                                       this->got_);
 340
 341       // The old GNU linker creates a .got.plt section.  We just
 342       // create another set of data in the .got section.  Note that we
 343       // always create a PLT if we create a GOT, although the PLT
 344       // might be empty.
 345       this->got_plt_ = new Output_data_space(8);
 346       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 347                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 348                                       this->got_plt_);
 349
 350       // The first three entries are reserved.
 351       this->got_plt_->set_current_data_size(3 * 8);
 352
 353       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 354       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 355                                     this->got_plt_,
 356                                     0, 0, elfcpp::STT_OBJECT,
 357                                     elfcpp::STB_LOCAL,
 358                                     elfcpp::STV_HIDDEN, 0,
 359                                     false, false);
 360     }
 361
 362   return this->got_;
 363 }
 364
 365 // Get the dynamic reloc section, creating it if necessary.
 366
 367 Target_x86_64::Reloc_section*
 368 Target_x86_64::rela_dyn_section(Layout* layout)
 369 {
 370   if (this->rela_dyn_ == NULL)
 371     {
 372       gold_assert(layout != NULL);
 373       this->rela_dyn_ = new Reloc_section();
 374       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 375                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 376     }
 377   return this->rela_dyn_;
 378 }
 379
 380 // A class to handle the PLT data.
 381
 382 class Output_data_plt_x86_64 : public Output_section_data
 383 {
 384  public:
 385   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 386
 387   Output_data_plt_x86_64(Layout*, Output_data_space*);
 388
 389   // Add an entry to the PLT.
 390   void
 391   add_entry(Symbol* gsym);
 392
 393   // Return the .rel.plt section data.
 394   const Reloc_section*
 395   rel_plt() const
 396   { return this->rel_; }
 397
 398  protected:
 399   void
 400   do_adjust_output_section(Output_section* os);
 401
 402  private:
 403   // The size of an entry in the PLT.
 404   static const int plt_entry_size = 16;
 405
 406   // The first entry in the PLT.
 407   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 408   // procedure linkage table for both programs and shared objects."
 409   static unsigned char first_plt_entry[plt_entry_size];
 410
 411   // Other entries in the PLT for an executable.
 412   static unsigned char plt_entry[plt_entry_size];
 413
 414   // Set the final size.
 415   void
 416   set_final_data_size()
 417   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 418
 419   // Write out the PLT data.
 420   void
 421   do_write(Output_file*);
 422
 423   // The reloc section.
 424   Reloc_section* rel_;
 425   // The .got.plt section.
 426   Output_data_space* got_plt_;
 427   // The number of PLT entries.
 428   unsigned int count_;
 429 };
 430
 431 // Create the PLT section.  The ordinary .got section is an argument,
 432 // since we need to refer to the start.  We also create our own .got
 433 // section just for PLT entries.
 434
 435 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 436                                                Output_data_space* got_plt)
 437   : Output_section_data(8), got_plt_(got_plt), count_(0)
 438 {
 439   this->rel_ = new Reloc_section();
 440   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 441                                   elfcpp::SHF_ALLOC, this->rel_);
 442 }
 443
 444 void
 445 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 446 {
 447   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 448   // linker, and so do we.
 449   os->set_entsize(4);
 450 }
 451
 452 // Add an entry to the PLT.
 453
 454 void
 455 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 456 {
 457   gold_assert(!gsym->has_plt_offset());
 458
 459   // Note that when setting the PLT offset we skip the initial
 460   // reserved PLT entry.
 461   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 462
 463   ++this->count_;
 464
 465   off_t got_offset = this->got_plt_->current_data_size();
 466
 467   // Every PLT entry needs a GOT entry which points back to the PLT
 468   // entry (this will be changed by the dynamic linker, normally
 469   // lazily when the function is called).
 470   this->got_plt_->set_current_data_size(got_offset + 8);
 471
 472   // Every PLT entry needs a reloc.
 473   gsym->set_needs_dynsym_entry();
 474   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 475                          got_offset, 0);
 476
 477   // Note that we don't need to save the symbol.  The contents of the
 478   // PLT are independent of which symbols are used.  The symbols only
 479   // appear in the relocations.
 480 }
 481
 482 // The first entry in the PLT for an executable.
 483
 484 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 485 {
 486   // From AMD64 ABI Draft 0.98, page 76
 487   0xff, 0x35,   // pushq contents of memory address
 488   0, 0, 0, 0,   // replaced with address of .got + 8
 489   0xff, 0x25,   // jmp indirect
 490   0, 0, 0, 0,   // replaced with address of .got + 16
 491   0x90, 0x90, 0x90, 0x90   // noop (x4)
 492 };
 493
 494 // Subsequent entries in the PLT for an executable.
 495
 496 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 497 {
 498   // From AMD64 ABI Draft 0.98, page 76
 499   0xff, 0x25,   // jmpq indirect
 500   0, 0, 0, 0,   // replaced with address of symbol in .got
 501   0x68,         // pushq immediate
 502   0, 0, 0, 0,   // replaced with offset into relocation table
 503   0xe9,         // jmpq relative
 504   0, 0, 0, 0    // replaced with offset to start of .plt
 505 };
 506
 507 // Write out the PLT.  This uses the hand-coded instructions above,
 508 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 509
 510 void
 511 Output_data_plt_x86_64::do_write(Output_file* of)
 512 {
 513   const off_t offset = this->offset();
 514   const off_t oview_size = this->data_size();
 515   unsigned char* const oview = of->get_output_view(offset, oview_size);
 516
 517   const off_t got_file_offset = this->got_plt_->offset();
 518   const off_t got_size = this->got_plt_->data_size();
 519   unsigned char* const got_view = of->get_output_view(got_file_offset,
 520                                                       got_size);
 521
 522   unsigned char* pov = oview;
 523
 524   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 525   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 526
 527   memcpy(pov, first_plt_entry, plt_entry_size);
 528   // We do a jmp relative to the PC at the end of this instruction.
 529   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
 530                                               - (plt_address + 6));
 531   elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
 532                                     - (plt_address + 12));
 533   pov += plt_entry_size;
 534
 535   unsigned char* got_pov = got_view;
 536
 537   memset(got_pov, 0, 24);
 538   got_pov += 24;
 539
 540   unsigned int plt_offset = plt_entry_size;
 541   unsigned int got_offset = 24;
 542   const unsigned int count = this->count_;
 543   for (unsigned int plt_index = 0;
 544        plt_index < count;
 545        ++plt_index,
 546          pov += plt_entry_size,
 547          got_pov += 8,
 548          plt_offset += plt_entry_size,
 549          got_offset += 8)
 550     {
 551       // Set and adjust the PLT entry itself.
 552       memcpy(pov, plt_entry, plt_entry_size);
 553       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 554                                                   (got_address + got_offset
 555                                                    - (plt_address + plt_offset
 556                                                       + 6)));
 557
 558       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 559       elfcpp::Swap<32, false>::writeval(pov + 12,
 560                                         - (plt_offset + plt_entry_size));
 561
 562       // Set the entry in the GOT.
 563       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 564     }
 565
 566   gold_assert(pov - oview == oview_size);
 567   gold_assert(got_pov - got_view == got_size);
 568
 569   of->write_output_view(offset, oview_size, oview);
 570   of->write_output_view(got_file_offset, got_size, got_view);
 571 }
 572
 573 // Create a PLT entry for a global symbol.
 574
 575 void
 576 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 577                               Symbol* gsym)
 578 {
 579   if (gsym->has_plt_offset())
 580     return;
 581
 582   if (this->plt_ == NULL)
 583     {
 584       // Create the GOT sections first.
 585       this->got_section(symtab, layout);
 586
 587       this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_);
 588       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 589                                       (elfcpp::SHF_ALLOC
 590                                        | elfcpp::SHF_EXECINSTR),
 591                                       this->plt_);
 592     }
 593
 594   this->plt_->add_entry(gsym);
 595 }
 596
 597 // Create a GOT entry for the TLS module index.
 598
 599 unsigned int
 600 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 601                                    Sized_relobj<64, false>* object)
 602 {
 603   if (this->got_mod_index_offset_ == -1U)
 604     {
 605       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 606       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 607       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 608       unsigned int got_offset = got->add_constant(0);
 609       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 610                           got_offset, 0);
 611       got->add_constant(0);
 612       this->got_mod_index_offset_ = got_offset;
 613     }
 614   return this->got_mod_index_offset_;
 615 }
 616
 617 // Handle a relocation against a non-function symbol defined in a
 618 // dynamic object.  The traditional way to handle this is to generate
 619 // a COPY relocation to copy the variable at runtime from the shared
 620 // object into the executable's data segment.  However, this is
 621 // undesirable in general, as if the size of the object changes in the
 622 // dynamic object, the executable will no longer work correctly.  If
 623 // this relocation is in a writable section, then we can create a
 624 // dynamic reloc and the dynamic linker will resolve it to the correct
 625 // address at runtime.  However, we do not want do that if the
 626 // relocation is in a read-only section, as it would prevent the
 627 // readonly segment from being shared.  And if we have to eventually
 628 // generate a COPY reloc, then any dynamic relocations will be
 629 // useless.  So this means that if this is a writable section, we need
 630 // to save the relocation until we see whether we have to create a
 631 // COPY relocation for this symbol for any other relocation.
 632
 633 void
 634 Target_x86_64::copy_reloc(const General_options* options,
 635                           Symbol_table* symtab,
 636                           Layout* layout,
 637                           Sized_relobj<64, false>* object,
 638                           unsigned int data_shndx,
 639                           Output_section* output_section,
 640                           Symbol* gsym,
 641                           const elfcpp::Rela<64, false>& rela)
 642 {
 643   Sized_symbol<64>* ssym;
 644   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(64) (gsym
 645                                                         SELECT_SIZE(64));
 646
 647   if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
 648                                                data_shndx, ssym))
 649     {
 650       // So far we do not need a COPY reloc.  Save this relocation.
 651       // If it turns out that we never need a COPY reloc for this
 652       // symbol, then we will emit the relocation.
 653       if (this->copy_relocs_ == NULL)
 654         this->copy_relocs_ = new Copy_relocs<64, false>();
 655       this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
 656     }
 657   else
 658     {
 659       // Allocate space for this symbol in the .bss section.
 660
 661       elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
 662
 663       // There is no defined way to determine the required alignment
 664       // of the symbol.  We pick the alignment based on the size.  We
 665       // set an arbitrary maximum of 256.
 666       unsigned int align;
 667       for (align = 1; align < 512; align <<= 1)
 668         if ((symsize & align) != 0)
 669           break;
 670
 671       if (this->dynbss_ == NULL)
 672         {
 673           this->dynbss_ = new Output_data_space(align);
 674           layout->add_output_section_data(".bss",
 675                                           elfcpp::SHT_NOBITS,
 676                                           (elfcpp::SHF_ALLOC
 677                                            | elfcpp::SHF_WRITE),
 678                                           this->dynbss_);
 679         }
 680
 681       Output_data_space* dynbss = this->dynbss_;
 682
 683       if (align > dynbss->addralign())
 684         dynbss->set_space_alignment(align);
 685
 686       off_t dynbss_size = dynbss->current_data_size();
 687       dynbss_size = align_address(dynbss_size, align);
 688       off_t offset = dynbss_size;
 689       dynbss->set_current_data_size(dynbss_size + symsize);
 690
 691       symtab->define_with_copy_reloc(this, ssym, dynbss, offset);
 692
 693       // Add the COPY reloc.
 694       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 695       rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
 696     }
 697 }
 698
 699
 700 // Optimize the TLS relocation type based on what we know about the
 701 // symbol.  IS_FINAL is true if the final address of this symbol is
 702 // known at link time.
 703
 704 tls::Tls_optimization
 705 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 706 {
 707   // If we are generating a shared library, then we can't do anything
 708   // in the linker.
 709   if (parameters->output_is_shared())
 710     return tls::TLSOPT_NONE;
 711
 712   switch (r_type)
 713     {
 714     case elfcpp::R_X86_64_TLSGD:
 715     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 716     case elfcpp::R_X86_64_TLSDESC_CALL:
 717       // These are General-Dynamic which permits fully general TLS
 718       // access.  Since we know that we are generating an executable,
 719       // we can convert this to Initial-Exec.  If we also know that
 720       // this is a local symbol, we can further switch to Local-Exec.
 721       if (is_final)
 722         return tls::TLSOPT_TO_LE;
 723       return tls::TLSOPT_TO_IE;
 724
 725     case elfcpp::R_X86_64_TLSLD:
 726       // This is Local-Dynamic, which refers to a local symbol in the
 727       // dynamic TLS block.  Since we know that we generating an
 728       // executable, we can switch to Local-Exec.
 729       return tls::TLSOPT_TO_LE;
 730
 731     case elfcpp::R_X86_64_DTPOFF32:
 732     case elfcpp::R_X86_64_DTPOFF64:
 733       // Another Local-Dynamic reloc.
 734       return tls::TLSOPT_TO_LE;
 735
 736     case elfcpp::R_X86_64_GOTTPOFF:
 737       // These are Initial-Exec relocs which get the thread offset
 738       // from the GOT.  If we know that we are linking against the
 739       // local symbol, we can switch to Local-Exec, which links the
 740       // thread offset into the instruction.
 741       if (is_final)
 742         return tls::TLSOPT_TO_LE;
 743       return tls::TLSOPT_NONE;
 744
 745     case elfcpp::R_X86_64_TPOFF32:
 746       // When we already have Local-Exec, there is nothing further we
 747       // can do.
 748       return tls::TLSOPT_NONE;
 749
 750     default:
 751       gold_unreachable();
 752     }
 753 }
 754
 755 // Report an unsupported relocation against a local symbol.
 756
 757 void
 758 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 759                                              unsigned int r_type)
 760 {
 761   gold_error(_("%s: unsupported reloc %u against local symbol"),
 762              object->name().c_str(), r_type);
 763 }
 764
 765 // Scan a relocation for a local symbol.
 766
 767 inline void
 768 Target_x86_64::Scan::local(const General_options&,
 769                            Symbol_table* symtab,
 770                            Layout* layout,
 771                            Target_x86_64* target,
 772                            Sized_relobj<64, false>* object,
 773                            unsigned int data_shndx,
 774                            Output_section* output_section,
 775                            const elfcpp::Rela<64, false>& reloc,
 776                            unsigned int r_type,
 777                            const elfcpp::Sym<64, false>& lsym)
 778 {
 779   switch (r_type)
 780     {
 781     case elfcpp::R_X86_64_NONE:
 782     case elfcpp::R_386_GNU_VTINHERIT:
 783     case elfcpp::R_386_GNU_VTENTRY:
 784       break;
 785
 786     case elfcpp::R_X86_64_64:
 787       // If building a shared library (or a position-independent
 788       // executable), we need to create a dynamic relocation for
 789       // this location. The relocation applied at link time will
 790       // apply the link-time value, so we flag the location with
 791       // an R_386_RELATIVE relocation so the dynamic loader can
 792       // relocate it easily.
 793       if (parameters->output_is_position_independent())
 794         {
 795           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 796           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 797           rela_dyn->add_local_relative(object, r_sym,
 798                                        elfcpp::R_X86_64_RELATIVE,
 799                                        output_section, data_shndx,
 800                                        reloc.get_r_offset(),
 801                                        reloc.get_r_addend());
 802         }
 803       break;
 804
 805     case elfcpp::R_X86_64_32:
 806     case elfcpp::R_X86_64_32S:
 807     case elfcpp::R_X86_64_16:
 808     case elfcpp::R_X86_64_8:
 809       // If building a shared library (or a position-independent
 810       // executable), we need to create a dynamic relocation for
 811       // this location. The relocation applied at link time will
 812       // apply the link-time value, so we flag the location with
 813       // an R_386_RELATIVE relocation so the dynamic loader can
 814       // relocate it easily.
 815       if (parameters->output_is_position_independent())
 816         {
 817           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 818           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 819           rela_dyn->add_local(object, r_sym, r_type, output_section,
 820                               data_shndx, reloc.get_r_offset(),
 821                               reloc.get_r_addend());
 822         }
 823       break;
 824
 825     case elfcpp::R_X86_64_PC64:
 826     case elfcpp::R_X86_64_PC32:
 827     case elfcpp::R_X86_64_PC16:
 828     case elfcpp::R_X86_64_PC8:
 829       break;
 830
 831     case elfcpp::R_X86_64_PLT32:
 832       // Since we know this is a local symbol, we can handle this as a
 833       // PC32 reloc.
 834       break;
 835
 836     case elfcpp::R_X86_64_GOTPC32:
 837     case elfcpp::R_X86_64_GOTOFF64:
 838     case elfcpp::R_X86_64_GOTPC64:
 839     case elfcpp::R_X86_64_PLTOFF64:
 840       // We need a GOT section.
 841       target->got_section(symtab, layout);
 842       // For PLTOFF64, we'd normally want a PLT section, but since we
 843       // know this is a local symbol, no PLT is needed.
 844       break;
 845
 846     case elfcpp::R_X86_64_GOT64:
 847     case elfcpp::R_X86_64_GOT32:
 848     case elfcpp::R_X86_64_GOTPCREL64:
 849     case elfcpp::R_X86_64_GOTPCREL:
 850     case elfcpp::R_X86_64_GOTPLT64:
 851       {
 852         // The symbol requires a GOT entry.
 853         Output_data_got<64, false>* got = target->got_section(symtab, layout);
 854         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 855         if (got->add_local(object, r_sym))
 856           {
 857             // If we are generating a shared object, we need to add a
 858             // dynamic relocation for this symbol's GOT entry.
 859             if (parameters->output_is_position_independent())
 860               {
 861                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 862                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
 863                 if (r_type != elfcpp::R_X86_64_GOT32)
 864                   rela_dyn->add_local_relative(object, r_sym,
 865                                                elfcpp::R_X86_64_RELATIVE, got,
 866                                                object->local_got_offset(r_sym),
 867                                                0);
 868                 else
 869                   rela_dyn->add_local(object, r_sym, r_type,
 870                                       got, object->local_got_offset(r_sym), 0);
 871               }
 872           }
 873         // For GOTPLT64, we'd normally want a PLT section, but since
 874         // we know this is a local symbol, no PLT is needed.
 875       }
 876       break;
 877
 878     case elfcpp::R_X86_64_COPY:
 879     case elfcpp::R_X86_64_GLOB_DAT:
 880     case elfcpp::R_X86_64_JUMP_SLOT:
 881     case elfcpp::R_X86_64_RELATIVE:
 882       // These are outstanding tls relocs, which are unexpected when linking
 883     case elfcpp::R_X86_64_TPOFF64:
 884     case elfcpp::R_X86_64_DTPMOD64:
 885     case elfcpp::R_X86_64_TLSDESC:
 886       gold_error(_("%s: unexpected reloc %u in object file"),
 887                  object->name().c_str(), r_type);
 888       break;
 889
 890       // These are initial tls relocs, which are expected when linking
 891     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
 892     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
 893     case elfcpp::R_X86_64_TLSDESC_CALL:
 894     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
 895     case elfcpp::R_X86_64_DTPOFF32:
 896     case elfcpp::R_X86_64_DTPOFF64:
 897     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
 898     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
 899       {
 900         bool output_is_shared = parameters->output_is_shared();
 901         const tls::Tls_optimization optimized_type
 902             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
 903         switch (r_type)
 904           {
 905           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
 906             if (optimized_type == tls::TLSOPT_NONE)
 907               {
 908                 // Create a pair of GOT entries for the module index and
 909                 // dtv-relative offset.
 910                 Output_data_got<64, false>* got
 911                     = target->got_section(symtab, layout);
 912                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 913                 got->add_local_tls_with_rela(object, r_sym,
 914                                              lsym.get_st_shndx(), true,
 915                                              target->rela_dyn_section(layout),
 916                                              elfcpp::R_X86_64_DTPMOD64);
 917               }
 918             else if (optimized_type != tls::TLSOPT_TO_LE)
 919               unsupported_reloc_local(object, r_type);
 920             break;
 921
 922           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 923           case elfcpp::R_X86_64_TLSDESC_CALL:
 924             // FIXME: If not relaxing to LE, we need to generate
 925             // a GOT entry with a R_x86_64_TLSDESC reloc.
 926             if (optimized_type != tls::TLSOPT_TO_LE)
 927               unsupported_reloc_local(object, r_type);
 928             break;
 929
 930           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
 931             if (optimized_type == tls::TLSOPT_NONE)
 932               {
 933                 // Create a GOT entry for the module index.
 934                 target->got_mod_index_entry(symtab, layout, object);
 935               }
 936             else if (optimized_type != tls::TLSOPT_TO_LE)
 937               unsupported_reloc_local(object, r_type);
 938             break;
 939
 940           case elfcpp::R_X86_64_DTPOFF32:
 941           case elfcpp::R_X86_64_DTPOFF64:
 942             break;
 943
 944           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
 945             layout->set_has_static_tls();
 946             if (optimized_type == tls::TLSOPT_NONE)
 947               {
 948                 // Create a GOT entry for the tp-relative offset.
 949                 Output_data_got<64, false>* got
 950                     = target->got_section(symtab, layout);
 951                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 952                 got->add_local_with_rela(object, r_sym,
 953                                          target->rela_dyn_section(layout),
 954                                          elfcpp::R_X86_64_TPOFF64);
 955               }
 956             else if (optimized_type != tls::TLSOPT_TO_LE)
 957               unsupported_reloc_local(object, r_type);
 958             break;
 959
 960           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
 961             layout->set_has_static_tls();
 962             if (output_is_shared)
 963               unsupported_reloc_local(object, r_type);
 964             break;
 965
 966           default:
 967             gold_unreachable();
 968           }
 969       }
 970       break;
 971
 972     case elfcpp::R_X86_64_SIZE32:
 973     case elfcpp::R_X86_64_SIZE64:
 974     default:
 975       gold_error(_("%s: unsupported reloc %u against local symbol"),
 976                  object->name().c_str(), r_type);
 977       break;
 978     }
 979 }
 980
 981
 982 // Report an unsupported relocation against a global symbol.
 983
 984 void
 985 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
 986                                               unsigned int r_type,
 987                                               Symbol* gsym)
 988 {
 989   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
 990              object->name().c_str(), r_type, gsym->demangled_name().c_str());
 991 }
 992
 993 // Scan a relocation for a global symbol.
 994
 995 inline void
 996 Target_x86_64::Scan::global(const General_options& options,
 997                             Symbol_table* symtab,
 998                             Layout* layout,
 999                             Target_x86_64* target,
1000                             Sized_relobj<64, false>* object,
1001                             unsigned int data_shndx,
1002                             Output_section* output_section,
1003                             const elfcpp::Rela<64, false>& reloc,
1004                             unsigned int r_type,
1005                             Symbol* gsym)
1006 {
1007   switch (r_type)
1008     {
1009     case elfcpp::R_X86_64_NONE:
1010     case elfcpp::R_386_GNU_VTINHERIT:
1011     case elfcpp::R_386_GNU_VTENTRY:
1012       break;
1013
1014     case elfcpp::R_X86_64_64:
1015     case elfcpp::R_X86_64_32:
1016     case elfcpp::R_X86_64_32S:
1017     case elfcpp::R_X86_64_16:
1018     case elfcpp::R_X86_64_8:
1019       {
1020         // Make a PLT entry if necessary.
1021         if (gsym->needs_plt_entry())
1022           {
1023             target->make_plt_entry(symtab, layout, gsym);
1024             // Since this is not a PC-relative relocation, we may be
1025             // taking the address of a function. In that case we need to
1026             // set the entry in the dynamic symbol table to the address of
1027             // the PLT entry.
1028             if (gsym->is_from_dynobj())
1029               gsym->set_needs_dynsym_value();
1030           }
1031         // Make a dynamic relocation if necessary.
1032         if (gsym->needs_dynamic_reloc(true, false))
1033           {
1034             if (target->may_need_copy_reloc(gsym))
1035               {
1036                 target->copy_reloc(&options, symtab, layout, object,
1037                                    data_shndx, output_section, gsym, reloc);
1038               }
1039             else if (r_type == elfcpp::R_X86_64_64
1040                      && gsym->can_use_relative_reloc(false))
1041               {
1042                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1043                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1044                                               output_section, object,
1045                                               data_shndx, reloc.get_r_offset(),
1046                                               reloc.get_r_addend());
1047               }
1048             else
1049               {
1050                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1051                 rela_dyn->add_global(gsym, r_type, output_section, object,
1052                                      data_shndx, reloc.get_r_offset(),
1053                                      reloc.get_r_addend());
1054               }
1055           }
1056       }
1057       break;
1058
1059     case elfcpp::R_X86_64_PC64:
1060     case elfcpp::R_X86_64_PC32:
1061     case elfcpp::R_X86_64_PC16:
1062     case elfcpp::R_X86_64_PC8:
1063       {
1064         // Make a PLT entry if necessary.
1065         if (gsym->needs_plt_entry())
1066           target->make_plt_entry(symtab, layout, gsym);
1067         // Make a dynamic relocation if necessary.
1068         bool is_function_call = (gsym->type() == elfcpp::STT_FUNC);
1069         if (gsym->needs_dynamic_reloc(false, is_function_call))
1070           {
1071             if (target->may_need_copy_reloc(gsym))
1072               {
1073                 target->copy_reloc(&options, symtab, layout, object,
1074                                    data_shndx, output_section, gsym, reloc);
1075               }
1076             else
1077               {
1078                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1079                 rela_dyn->add_global(gsym, r_type, output_section, object,
1080                                      data_shndx, reloc.get_r_offset(),
1081                                      reloc.get_r_addend());
1082               }
1083           }
1084       }
1085       break;
1086
1087     case elfcpp::R_X86_64_GOT64:
1088     case elfcpp::R_X86_64_GOT32:
1089     case elfcpp::R_X86_64_GOTPCREL64:
1090     case elfcpp::R_X86_64_GOTPCREL:
1091     case elfcpp::R_X86_64_GOTPLT64:
1092       {
1093         // The symbol requires a GOT entry.
1094         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1095         if (gsym->final_value_is_known())
1096           got->add_global(gsym);
1097         else
1098           {
1099             // If this symbol is not fully resolved, we need to add a
1100             // dynamic relocation for it.
1101             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1102             if (gsym->is_from_dynobj() || gsym->is_preemptible())
1103               got->add_global_with_rela(gsym, rela_dyn,
1104                                         elfcpp::R_X86_64_GLOB_DAT);
1105             else
1106               {
1107                 if (got->add_global(gsym))
1108                   rela_dyn->add_global_relative(gsym,
1109                                                 elfcpp::R_X86_64_RELATIVE,
1110                                                 got, gsym->got_offset(), 0);
1111               }
1112           }
1113         // For GOTPLT64, we also need a PLT entry (but only if the
1114         // symbol is not fully resolved).
1115         if (r_type == elfcpp::R_X86_64_GOTPLT64
1116             && !gsym->final_value_is_known())
1117           target->make_plt_entry(symtab, layout, gsym);
1118       }
1119       break;
1120
1121     case elfcpp::R_X86_64_PLT32:
1122       // If the symbol is fully resolved, this is just a PC32 reloc.
1123       // Otherwise we need a PLT entry.
1124       if (gsym->final_value_is_known())
1125         break;
1126       // If building a shared library, we can also skip the PLT entry
1127       // if the symbol is defined in the output file and is protected
1128       // or hidden.
1129       if (gsym->is_defined()
1130           && !gsym->is_from_dynobj()
1131           && !gsym->is_preemptible())
1132         break;
1133       target->make_plt_entry(symtab, layout, gsym);
1134       break;
1135
1136     case elfcpp::R_X86_64_GOTPC32:
1137     case elfcpp::R_X86_64_GOTOFF64:
1138     case elfcpp::R_X86_64_GOTPC64:
1139     case elfcpp::R_X86_64_PLTOFF64:
1140       // We need a GOT section.
1141       target->got_section(symtab, layout);
1142       // For PLTOFF64, we also need a PLT entry (but only if the
1143       // symbol is not fully resolved).
1144       if (r_type == elfcpp::R_X86_64_PLTOFF64
1145           && !gsym->final_value_is_known())
1146         target->make_plt_entry(symtab, layout, gsym);
1147       break;
1148
1149     case elfcpp::R_X86_64_COPY:
1150     case elfcpp::R_X86_64_GLOB_DAT:
1151     case elfcpp::R_X86_64_JUMP_SLOT:
1152     case elfcpp::R_X86_64_RELATIVE:
1153       // These are outstanding tls relocs, which are unexpected when linking
1154     case elfcpp::R_X86_64_TPOFF64:
1155     case elfcpp::R_X86_64_DTPMOD64:
1156     case elfcpp::R_X86_64_TLSDESC:
1157       gold_error(_("%s: unexpected reloc %u in object file"),
1158                  object->name().c_str(), r_type);
1159       break;
1160
1161       // These are initial tls relocs, which are expected for global()
1162     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1163     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1164     case elfcpp::R_X86_64_TLSDESC_CALL:
1165     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1166     case elfcpp::R_X86_64_DTPOFF32:
1167     case elfcpp::R_X86_64_DTPOFF64:
1168     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1169     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1170       {
1171         const bool is_final = gsym->final_value_is_known();
1172         const tls::Tls_optimization optimized_type
1173             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1174         switch (r_type)
1175           {
1176           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1177             if (optimized_type == tls::TLSOPT_NONE)
1178               {
1179                 // Create a pair of GOT entries for the module index and
1180                 // dtv-relative offset.
1181                 Output_data_got<64, false>* got
1182                     = target->got_section(symtab, layout);
1183                 got->add_global_tls_with_rela(gsym,
1184                                               target->rela_dyn_section(layout),
1185                                               elfcpp::R_X86_64_DTPMOD64,
1186                                               elfcpp::R_X86_64_DTPOFF64);
1187               }
1188             else if (optimized_type == tls::TLSOPT_TO_IE)
1189               {
1190                 // Create a GOT entry for the tp-relative offset.
1191                 Output_data_got<64, false>* got
1192                     = target->got_section(symtab, layout);
1193                 got->add_global_with_rela(gsym,
1194                                           target->rela_dyn_section(layout),
1195                                           elfcpp::R_X86_64_TPOFF64);
1196               }
1197             else if (optimized_type != tls::TLSOPT_TO_LE)
1198               unsupported_reloc_global(object, r_type, gsym);
1199             break;
1200
1201           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1202           case elfcpp::R_X86_64_TLSDESC_CALL:
1203             // FIXME: If not relaxing to LE, we need to generate
1204             // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1205             if (optimized_type != tls::TLSOPT_TO_LE)
1206               unsupported_reloc_global(object, r_type, gsym);
1207             break;
1208
1209           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1210             if (optimized_type == tls::TLSOPT_NONE)
1211               {
1212                 // Create a GOT entry for the module index.
1213                 target->got_mod_index_entry(symtab, layout, object);
1214               }
1215             else if (optimized_type != tls::TLSOPT_TO_LE)
1216               unsupported_reloc_global(object, r_type, gsym);
1217             break;
1218
1219           case elfcpp::R_X86_64_DTPOFF32:
1220           case elfcpp::R_X86_64_DTPOFF64:
1221             break;
1222
1223           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1224             layout->set_has_static_tls();
1225             if (optimized_type == tls::TLSOPT_NONE)
1226               {
1227                 // Create a GOT entry for the tp-relative offset.
1228                 Output_data_got<64, false>* got
1229                     = target->got_section(symtab, layout);
1230                 got->add_global_with_rela(gsym,
1231                                           target->rela_dyn_section(layout),
1232                                           elfcpp::R_X86_64_TPOFF64);
1233               }
1234             else if (optimized_type != tls::TLSOPT_TO_LE)
1235               unsupported_reloc_global(object, r_type, gsym);
1236             break;
1237
1238           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1239             layout->set_has_static_tls();
1240             if (parameters->output_is_shared())
1241               unsupported_reloc_local(object, r_type);
1242             break;
1243
1244           default:
1245             gold_unreachable();
1246           }
1247       }
1248       break;
1249
1250     case elfcpp::R_X86_64_SIZE32:
1251     case elfcpp::R_X86_64_SIZE64:
1252     default:
1253       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1254                  object->name().c_str(), r_type,
1255                  gsym->demangled_name().c_str());
1256       break;
1257     }
1258 }
1259
1260 // Scan relocations for a section.
1261
1262 void
1263 Target_x86_64::scan_relocs(const General_options& options,
1264                            Symbol_table* symtab,
1265                            Layout* layout,
1266                            Sized_relobj<64, false>* object,
1267                            unsigned int data_shndx,
1268                            unsigned int sh_type,
1269                            const unsigned char* prelocs,
1270                            size_t reloc_count,
1271                            Output_section* output_section,
1272                            bool needs_special_offset_handling,
1273                            size_t local_symbol_count,
1274                            const unsigned char* plocal_symbols)
1275 {
1276   if (sh_type == elfcpp::SHT_REL)
1277     {
1278       gold_error(_("%s: unsupported REL reloc section"),
1279                  object->name().c_str());
1280       return;
1281     }
1282
1283   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1284       Target_x86_64::Scan>(
1285     options,
1286     symtab,
1287     layout,
1288     this,
1289     object,
1290     data_shndx,
1291     prelocs,
1292     reloc_count,
1293     output_section,
1294     needs_special_offset_handling,
1295     local_symbol_count,
1296     plocal_symbols);
1297 }
1298
1299 // Finalize the sections.
1300
1301 void
1302 Target_x86_64::do_finalize_sections(Layout* layout)
1303 {
1304   // Fill in some more dynamic tags.
1305   Output_data_dynamic* const odyn = layout->dynamic_data();
1306   if (odyn != NULL)
1307     {
1308       if (this->got_plt_ != NULL)
1309         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1310
1311       if (this->plt_ != NULL)
1312         {
1313           const Output_data* od = this->plt_->rel_plt();
1314           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1315           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1316           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1317         }
1318
1319       if (this->rela_dyn_ != NULL)
1320         {
1321           const Output_data* od = this->rela_dyn_;
1322           odyn->add_section_address(elfcpp::DT_RELA, od);
1323           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1324           odyn->add_constant(elfcpp::DT_RELAENT,
1325                              elfcpp::Elf_sizes<64>::rela_size);
1326         }
1327
1328       if (!parameters->output_is_shared())
1329         {
1330           // The value of the DT_DEBUG tag is filled in by the dynamic
1331           // linker at run time, and used by the debugger.
1332           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1333         }
1334     }
1335
1336   // Emit any relocs we saved in an attempt to avoid generating COPY
1337   // relocs.
1338   if (this->copy_relocs_ == NULL)
1339     return;
1340   if (this->copy_relocs_->any_to_emit())
1341     {
1342       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1343       this->copy_relocs_->emit(rela_dyn);
1344     }
1345   delete this->copy_relocs_;
1346   this->copy_relocs_ = NULL;
1347 }
1348
1349 // Perform a relocation.
1350
1351 inline bool
1352 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1353                                   Target_x86_64* target,
1354                                   size_t relnum,
1355                                   const elfcpp::Rela<64, false>& rela,
1356                                   unsigned int r_type,
1357                                   const Sized_symbol<64>* gsym,
1358                                   const Symbol_value<64>* psymval,
1359                                   unsigned char* view,
1360                                   elfcpp::Elf_types<64>::Elf_Addr address,
1361                                   off_t view_size)
1362 {
1363   if (this->skip_call_tls_get_addr_)
1364     {
1365       if (r_type != elfcpp::R_X86_64_PLT32
1366           || gsym == NULL
1367           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1368         {
1369           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1370                                  _("missing expected TLS relocation"));
1371         }
1372       else
1373         {
1374           this->skip_call_tls_get_addr_ = false;
1375           return false;
1376         }
1377     }
1378
1379   // Pick the value to use for symbols defined in shared objects.
1380   Symbol_value<64> symval;
1381   if (gsym != NULL
1382       && (gsym->is_from_dynobj()
1383           || (parameters->output_is_shared()
1384               && gsym->is_preemptible()))
1385       && gsym->has_plt_offset())
1386     {
1387       symval.set_output_value(target->plt_section()->address()
1388                               + gsym->plt_offset());
1389       psymval = &symval;
1390     }
1391
1392   const Sized_relobj<64, false>* object = relinfo->object;
1393   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1394
1395   // Get the GOT offset if needed.
1396   // The GOT pointer points to the end of the GOT section.
1397   // We need to subtract the size of the GOT section to get
1398   // the actual offset to use in the relocation.
1399   bool have_got_offset = false;
1400   unsigned int got_offset = 0;
1401   switch (r_type)
1402     {
1403     case elfcpp::R_X86_64_GOT32:
1404     case elfcpp::R_X86_64_GOT64:
1405     case elfcpp::R_X86_64_GOTPLT64:
1406     case elfcpp::R_X86_64_GOTPCREL:
1407     case elfcpp::R_X86_64_GOTPCREL64:
1408       if (gsym != NULL)
1409         {
1410           gold_assert(gsym->has_got_offset());
1411           got_offset = gsym->got_offset() - target->got_size();
1412         }
1413       else
1414         {
1415           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1416           gold_assert(object->local_has_got_offset(r_sym));
1417           got_offset = object->local_got_offset(r_sym) - target->got_size();
1418         }
1419       have_got_offset = true;
1420       break;
1421
1422     default:
1423       break;
1424     }
1425
1426   switch (r_type)
1427     {
1428     case elfcpp::R_X86_64_NONE:
1429     case elfcpp::R_386_GNU_VTINHERIT:
1430     case elfcpp::R_386_GNU_VTENTRY:
1431       break;
1432
1433     case elfcpp::R_X86_64_64:
1434       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1435       break;
1436
1437     case elfcpp::R_X86_64_PC64:
1438       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1439                                               address);
1440       break;
1441
1442     case elfcpp::R_X86_64_32:
1443       // FIXME: we need to verify that value + addend fits into 32 bits:
1444       //    uint64_t x = value + addend;
1445       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1446       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1447       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1448       break;
1449
1450     case elfcpp::R_X86_64_32S:
1451       // FIXME: we need to verify that value + addend fits into 32 bits:
1452       //    int64_t x = value + addend;   // note this quantity is signed!
1453       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1454       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1455       break;
1456
1457     case elfcpp::R_X86_64_PC32:
1458       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1459                                               address);
1460       break;
1461
1462     case elfcpp::R_X86_64_16:
1463       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1464       break;
1465
1466     case elfcpp::R_X86_64_PC16:
1467       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1468                                               address);
1469       break;
1470
1471     case elfcpp::R_X86_64_8:
1472       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1473       break;
1474
1475     case elfcpp::R_X86_64_PC8:
1476       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1477                                              address);
1478       break;
1479
1480     case elfcpp::R_X86_64_PLT32:
1481       gold_assert(gsym == NULL
1482                   || gsym->has_plt_offset()
1483                   || gsym->final_value_is_known());
1484       // Note: while this code looks the same as for R_X86_64_PC32, it
1485       // behaves differently because psymval was set to point to
1486       // the PLT entry, rather than the symbol, in Scan::global().
1487       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1488                                               address);
1489       break;
1490
1491     case elfcpp::R_X86_64_PLTOFF64:
1492       {
1493         gold_assert(gsym);
1494         gold_assert(gsym->has_plt_offset()
1495                     || gsym->final_value_is_known());
1496         elfcpp::Elf_types<64>::Elf_Addr got_address;
1497         got_address = target->got_section(NULL, NULL)->address();
1498         Relocate_functions<64, false>::rela64(view, object, psymval,
1499                                               addend - got_address);
1500       }
1501
1502     case elfcpp::R_X86_64_GOT32:
1503       gold_assert(have_got_offset);
1504       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1505       break;
1506
1507     case elfcpp::R_X86_64_GOTPC32:
1508       {
1509         gold_assert(gsym);
1510         elfcpp::Elf_types<64>::Elf_Addr value;
1511         value = target->got_plt_section()->address();
1512         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1513       }
1514       break;
1515
1516     case elfcpp::R_X86_64_GOT64:
1517       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1518       // Since we always add a PLT entry, this is equivalent.
1519     case elfcpp::R_X86_64_GOTPLT64:
1520       gold_assert(have_got_offset);
1521       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1522       break;
1523
1524     case elfcpp::R_X86_64_GOTPC64:
1525       {
1526         gold_assert(gsym);
1527         elfcpp::Elf_types<64>::Elf_Addr value;
1528         value = target->got_plt_section()->address();
1529         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1530       }
1531       break;
1532
1533     case elfcpp::R_X86_64_GOTOFF64:
1534       {
1535         elfcpp::Elf_types<64>::Elf_Addr value;
1536         value = (psymval->value(object, 0)
1537                  - target->got_plt_section()->address());
1538         Relocate_functions<64, false>::rela64(view, value, addend);
1539       }
1540       break;
1541
1542     case elfcpp::R_X86_64_GOTPCREL:
1543       {
1544         gold_assert(have_got_offset);
1545         elfcpp::Elf_types<64>::Elf_Addr value;
1546         value = target->got_plt_section()->address() + got_offset;
1547         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1548       }
1549       break;
1550
1551     case elfcpp::R_X86_64_GOTPCREL64:
1552       {
1553         gold_assert(have_got_offset);
1554         elfcpp::Elf_types<64>::Elf_Addr value;
1555         value = target->got_plt_section()->address() + got_offset;
1556         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1557       }
1558       break;
1559
1560     case elfcpp::R_X86_64_COPY:
1561     case elfcpp::R_X86_64_GLOB_DAT:
1562     case elfcpp::R_X86_64_JUMP_SLOT:
1563     case elfcpp::R_X86_64_RELATIVE:
1564       // These are outstanding tls relocs, which are unexpected when linking
1565     case elfcpp::R_X86_64_TPOFF64:
1566     case elfcpp::R_X86_64_DTPMOD64:
1567     case elfcpp::R_X86_64_TLSDESC:
1568       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1569                              _("unexpected reloc %u in object file"),
1570                              r_type);
1571       break;
1572
1573       // These are initial tls relocs, which are expected when linking
1574     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1575     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1576     case elfcpp::R_X86_64_TLSDESC_CALL:
1577     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1578     case elfcpp::R_X86_64_DTPOFF32:
1579     case elfcpp::R_X86_64_DTPOFF64:
1580     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1581     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1582       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1583                          view, address, view_size);
1584       break;
1585
1586     case elfcpp::R_X86_64_SIZE32:
1587     case elfcpp::R_X86_64_SIZE64:
1588     default:
1589       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1590                              _("unsupported reloc %u"),
1591                              r_type);
1592       break;
1593     }
1594
1595   return true;
1596 }
1597
1598 // Perform a TLS relocation.
1599
1600 inline void
1601 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1602                                       Target_x86_64* target,
1603                                       size_t relnum,
1604                                       const elfcpp::Rela<64, false>& rela,
1605                                       unsigned int r_type,
1606                                       const Sized_symbol<64>* gsym,
1607                                       const Symbol_value<64>* psymval,
1608                                       unsigned char* view,
1609                                       elfcpp::Elf_types<64>::Elf_Addr address,
1610                                       off_t view_size)
1611 {
1612   Output_segment* tls_segment = relinfo->layout->tls_segment();
1613
1614   const Sized_relobj<64, false>* object = relinfo->object;
1615   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1616
1617   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1618
1619   const bool is_final = (gsym == NULL
1620                          ? !parameters->output_is_position_independent()
1621                          : gsym->final_value_is_known());
1622   const tls::Tls_optimization optimized_type
1623       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1624   switch (r_type)
1625     {
1626     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1627     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1628     case elfcpp::R_X86_64_TLSDESC_CALL:
1629       if (optimized_type == tls::TLSOPT_TO_LE)
1630         {
1631           gold_assert(tls_segment != NULL);
1632           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1633                              rela, r_type, value, view,
1634                              view_size);
1635           break;
1636         }
1637       else
1638         {
1639           unsigned int got_offset;
1640           if (gsym != NULL)
1641             {
1642               gold_assert(gsym->has_tls_got_offset(true));
1643               got_offset = gsym->tls_got_offset(true) - target->got_size();
1644             }
1645           else
1646             {
1647               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1648               gold_assert(object->local_has_tls_got_offset(r_sym, true));
1649               got_offset = (object->local_tls_got_offset(r_sym, true)
1650                             - target->got_size());
1651             }
1652           if (optimized_type == tls::TLSOPT_TO_IE)
1653             {
1654               gold_assert(tls_segment != NULL);
1655               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
1656                                  got_offset, view, view_size);
1657               break;
1658             }
1659           else if (optimized_type == tls::TLSOPT_NONE)
1660             {
1661               // Relocate the field with the offset of the pair of GOT
1662               // entries.
1663               value = target->got_plt_section()->address() + got_offset;
1664               Relocate_functions<64, false>::pcrela32(view, value, addend,
1665                                                       address);
1666               break;
1667             }
1668         }
1669       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1670                              _("unsupported reloc %u"), r_type);
1671       break;
1672
1673     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1674       if (optimized_type == tls::TLSOPT_TO_LE)
1675         {
1676           gold_assert(tls_segment != NULL);
1677           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
1678                              value, view, view_size);
1679           break;
1680         }
1681       else if (optimized_type == tls::TLSOPT_NONE)
1682         {
1683           // Relocate the field with the offset of the GOT entry for
1684           // the module index.
1685           unsigned int got_offset;
1686           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
1687                         - target->got_size());
1688           value = target->got_plt_section()->address() + got_offset;
1689           Relocate_functions<64, false>::pcrela32(view, value, addend,
1690                                                   address);
1691           break;
1692         }
1693       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1694                              _("unsupported reloc %u"), r_type);
1695       break;
1696
1697     case elfcpp::R_X86_64_DTPOFF32:
1698       gold_assert(tls_segment != NULL);
1699       if (optimized_type == tls::TLSOPT_TO_LE)
1700         value -= tls_segment->memsz();
1701       Relocate_functions<64, false>::rela32(view, value, 0);
1702       break;
1703
1704     case elfcpp::R_X86_64_DTPOFF64:
1705       gold_assert(tls_segment != NULL);
1706       if (optimized_type == tls::TLSOPT_TO_LE)
1707         value -= tls_segment->memsz();
1708       Relocate_functions<64, false>::rela64(view, value, 0);
1709       break;
1710
1711     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1712       if (optimized_type == tls::TLSOPT_TO_LE)
1713         {
1714           gold_assert(tls_segment != NULL);
1715           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1716                                                 rela, r_type, value, view,
1717                                                 view_size);
1718           break;
1719         }
1720       else if (optimized_type == tls::TLSOPT_NONE)
1721         {
1722           // Relocate the field with the offset of the GOT entry for
1723           // the tp-relative offset of the symbol.
1724           unsigned int got_offset;
1725           if (gsym != NULL)
1726             {
1727               gold_assert(gsym->has_got_offset());
1728               got_offset = gsym->got_offset() - target->got_size();
1729             }
1730           else
1731             {
1732               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1733               gold_assert(object->local_has_got_offset(r_sym));
1734               got_offset = (object->local_got_offset(r_sym)
1735                             - target->got_size());
1736             }
1737           value = target->got_plt_section()->address() + got_offset;
1738           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1739           break;
1740         }
1741       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1742                              _("unsupported reloc type %u"),
1743                              r_type);
1744       break;
1745
1746     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1747       value -= tls_segment->memsz();
1748       Relocate_functions<64, false>::rela32(view, value, 0);
1749       break;
1750     }
1751 }
1752
1753 // Do a relocation in which we convert a TLS General-Dynamic to an
1754 // Initial-Exec.
1755
1756 inline void
1757 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
1758                                       size_t relnum,
1759                                       Output_segment* tls_segment,
1760                                       const elfcpp::Rela<64, false>& rela,
1761                                       unsigned int,
1762                                       elfcpp::Elf_types<64>::Elf_Addr value,
1763                                       unsigned char* view,
1764                                       off_t view_size)
1765 {
1766   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1767   // .word 0x6666; rex64; call __tls_get_addr
1768   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
1769
1770   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1771   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1772
1773   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1774                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1775   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1776                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1777
1778   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
1779
1780   value -= tls_segment->memsz();
1781   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1782
1783   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1784   // We can skip it.
1785   this->skip_call_tls_get_addr_ = true;
1786 }
1787
1788 // Do a relocation in which we convert a TLS General-Dynamic to a
1789 // Local-Exec.
1790
1791 inline void
1792 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
1793                                       size_t relnum,
1794                                       Output_segment* tls_segment,
1795                                       const elfcpp::Rela<64, false>& rela,
1796                                       unsigned int,
1797                                       elfcpp::Elf_types<64>::Elf_Addr value,
1798                                       unsigned char* view,
1799                                       off_t view_size)
1800 {
1801   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1802   // .word 0x6666; rex64; call __tls_get_addr
1803   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1804
1805   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1806   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1807
1808   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1809                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1810   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1811                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1812
1813   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1814
1815   value -= tls_segment->memsz();
1816   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1817
1818   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1819   // We can skip it.
1820   this->skip_call_tls_get_addr_ = true;
1821 }
1822
1823 inline void
1824 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
1825                                       size_t relnum,
1826                                       Output_segment*,
1827                                       const elfcpp::Rela<64, false>& rela,
1828                                       unsigned int,
1829                                       elfcpp::Elf_types<64>::Elf_Addr,
1830                                       unsigned char* view,
1831                                       off_t view_size)
1832 {
1833   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1834   // ... leq foo@dtpoff(%rax),%reg
1835   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1836
1837   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1838   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
1839
1840   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1841                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
1842
1843   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
1844
1845   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1846
1847   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1848   // We can skip it.
1849   this->skip_call_tls_get_addr_ = true;
1850 }
1851
1852 // Do a relocation in which we convert a TLS Initial-Exec to a
1853 // Local-Exec.
1854
1855 inline void
1856 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
1857                                       size_t relnum,
1858                                       Output_segment* tls_segment,
1859                                       const elfcpp::Rela<64, false>& rela,
1860                                       unsigned int,
1861                                       elfcpp::Elf_types<64>::Elf_Addr value,
1862                                       unsigned char* view,
1863                                       off_t view_size)
1864 {
1865   // We need to examine the opcodes to figure out which instruction we
1866   // are looking at.
1867
1868   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
1869   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
1870
1871   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1872   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
1873
1874   unsigned char op1 = view[-3];
1875   unsigned char op2 = view[-2];
1876   unsigned char op3 = view[-1];
1877   unsigned char reg = op3 >> 3;
1878
1879   if (op2 == 0x8b)
1880     {
1881       // movq
1882       if (op1 == 0x4c)
1883         view[-3] = 0x49;
1884       view[-2] = 0xc7;
1885       view[-1] = 0xc0 | reg;
1886     }
1887   else if (reg == 4)
1888     {
1889       // Special handling for %rsp.
1890       if (op1 == 0x4c)
1891         view[-3] = 0x49;
1892       view[-2] = 0x81;
1893       view[-1] = 0xc0 | reg;
1894     }
1895   else
1896     {
1897       // addq
1898       if (op1 == 0x4c)
1899         view[-3] = 0x4d;
1900       view[-2] = 0x8d;
1901       view[-1] = 0x80 | reg | (reg << 3);
1902     }
1903
1904   value -= tls_segment->memsz();
1905   Relocate_functions<64, false>::rela32(view, value, 0);
1906 }
1907
1908 // Relocate section data.
1909
1910 void
1911 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
1912                                 unsigned int sh_type,
1913                                 const unsigned char* prelocs,
1914                                 size_t reloc_count,
1915                                 Output_section* output_section,
1916                                 bool needs_special_offset_handling,
1917                                 unsigned char* view,
1918                                 elfcpp::Elf_types<64>::Elf_Addr address,
1919                                 off_t view_size)
1920 {
1921   gold_assert(sh_type == elfcpp::SHT_RELA);
1922
1923   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
1924                          Target_x86_64::Relocate>(
1925     relinfo,
1926     this,
1927     prelocs,
1928     reloc_count,
1929     output_section,
1930     needs_special_offset_handling,
1931     view,
1932     address,
1933     view_size);
1934 }
1935
1936 // Return the value to use for a dynamic which requires special
1937 // treatment.  This is how we support equality comparisons of function
1938 // pointers across shared library boundaries, as described in the
1939 // processor specific ABI supplement.
1940
1941 uint64_t
1942 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
1943 {
1944   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1945   return this->plt_section()->address() + gsym->plt_offset();
1946 }
1947
1948 // Return a string used to fill a code section with nops to take up
1949 // the specified length.
1950
1951 std::string
1952 Target_x86_64::do_code_fill(off_t length)
1953 {
1954   if (length >= 16)
1955     {
1956       // Build a jmpq instruction to skip over the bytes.
1957       unsigned char jmp[5];
1958       jmp[0] = 0xe9;
1959       elfcpp::Swap_unaligned<64, false>::writeval(jmp + 1, length - 5);
1960       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1961               + std::string(length - 5, '\0'));
1962     }
1963
1964   // Nop sequences of various lengths.
1965   const char nop1[1] = { 0x90 };                   // nop
1966   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1967   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1968   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1969   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1970                          0x00 };                   // leal 0(%esi,1),%esi
1971   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1972                          0x00, 0x00 };
1973   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1974                          0x00, 0x00, 0x00 };
1975   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1976                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1977   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1978                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1979                          0x00 };
1980   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1981                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1982                            0x00, 0x00 };
1983   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1984                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1985                            0x00, 0x00, 0x00 };
1986   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1987                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1988                            0x00, 0x00, 0x00, 0x00 };
1989   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1990                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1991                            0x27, 0x00, 0x00, 0x00,
1992                            0x00 };
1993   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1994                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1995                            0xbc, 0x27, 0x00, 0x00,
1996                            0x00, 0x00 };
1997   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1998                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1999                            0x90, 0x90, 0x90, 0x90,
2000                            0x90, 0x90, 0x90 };
2001
2002   const char* nops[16] = {
2003     NULL,
2004     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2005     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2006   };
2007
2008   return std::string(nops[length], length);
2009 }
2010
2011 // The selector for x86_64 object files.
2012
2013 class Target_selector_x86_64 : public Target_selector
2014 {
2015 public:
2016   Target_selector_x86_64()
2017     : Target_selector(elfcpp::EM_X86_64, 64, false)
2018   { }
2019
2020   Target*
2021   recognize(int machine, int osabi, int abiversion);
2022
2023  private:
2024   Target_x86_64* target_;
2025 };
2026
2027 // Recognize an x86_64 object file when we already know that the machine
2028 // number is EM_X86_64.
2029
2030 Target*
2031 Target_selector_x86_64::recognize(int, int, int)
2032 {
2033   if (this->target_ == NULL)
2034     this->target_ = new Target_x86_64();
2035   return this->target_;
2036 }
2037
2038 Target_selector_x86_64 target_selector_x86_64;
2039
2040 } // End anonymous namespace.