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                    section_size_type view_size);
 111
 112   // Return a string used to fill a code section with nops.
 113   std::string
 114   do_code_fill(section_size_type 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   section_size_type
 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              section_size_type);
 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,
 194                  section_size_type);
 195
 196     // Do a TLS General-Dynamic to Local-Exec transition.
 197     inline void
 198     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 199                  Output_segment* tls_segment,
 200                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 201                  elfcpp::Elf_types<64>::Elf_Addr value,
 202                  unsigned char* view,
 203                  section_size_type view_size);
 204
 205     // Do a TLS General-Dynamic to Local-Exec transition.
 206     inline void
 207     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 208                  Output_segment* tls_segment,
 209                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 210                  elfcpp::Elf_types<64>::Elf_Addr value,
 211                  unsigned char* view,
 212                  section_size_type view_size);
 213
 214     // Do a TLS Local-Dynamic to Local-Exec transition.
 215     inline void
 216     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 217                  Output_segment* tls_segment,
 218                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 219                  elfcpp::Elf_types<64>::Elf_Addr value,
 220                  unsigned char* view,
 221                  section_size_type view_size);
 222
 223     // Do a TLS Initial-Exec to Local-Exec transition.
 224     static inline void
 225     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 226                  Output_segment* tls_segment,
 227                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 228                  elfcpp::Elf_types<64>::Elf_Addr value,
 229                  unsigned char* view,
 230                  section_size_type view_size);
 231
 232     // This is set if we should skip the next reloc, which should be a
 233     // PLT32 reloc against ___tls_get_addr.
 234     bool skip_call_tls_get_addr_;
 235   };
 236
 237   // Adjust TLS relocation type based on the options and whether this
 238   // is a local symbol.
 239   static tls::Tls_optimization
 240   optimize_tls_reloc(bool is_final, int r_type);
 241
 242   // Get the GOT section, creating it if necessary.
 243   Output_data_got<64, false>*
 244   got_section(Symbol_table*, Layout*);
 245
 246   // Get the GOT PLT section.
 247   Output_data_space*
 248   got_plt_section() const
 249   {
 250     gold_assert(this->got_plt_ != NULL);
 251     return this->got_plt_;
 252   }
 253
 254   // Create a PLT entry for a global symbol.
 255   void
 256   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 257
 258   // Create a GOT entry for the TLS module index.
 259   unsigned int
 260   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 261                       Sized_relobj<64, false>* object);
 262
 263   // Get the PLT section.
 264   Output_data_plt_x86_64*
 265   plt_section() const
 266   {
 267     gold_assert(this->plt_ != NULL);
 268     return this->plt_;
 269   }
 270
 271   // Get the dynamic reloc section, creating it if necessary.
 272   Reloc_section*
 273   rela_dyn_section(Layout*);
 274
 275   // Return true if the symbol may need a COPY relocation.
 276   // References from an executable object to non-function symbols
 277   // defined in a dynamic object may need a COPY relocation.
 278   bool
 279   may_need_copy_reloc(Symbol* gsym)
 280   {
 281     return (!parameters->output_is_shared()
 282             && gsym->is_from_dynobj()
 283             && gsym->type() != elfcpp::STT_FUNC);
 284   }
 285
 286   // Copy a relocation against a global symbol.
 287   void
 288   copy_reloc(const General_options*, Symbol_table*, Layout*,
 289              Sized_relobj<64, false>*, unsigned int,
 290              Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
 291
 292   // Information about this specific target which we pass to the
 293   // general Target structure.
 294   static const Target::Target_info x86_64_info;
 295
 296   // The GOT section.
 297   Output_data_got<64, false>* got_;
 298   // The PLT section.
 299   Output_data_plt_x86_64* plt_;
 300   // The GOT PLT section.
 301   Output_data_space* got_plt_;
 302   // The dynamic reloc section.
 303   Reloc_section* rela_dyn_;
 304   // Relocs saved to avoid a COPY reloc.
 305   Copy_relocs<64, false>* copy_relocs_;
 306   // Space for variables copied with a COPY reloc.
 307   Output_data_space* dynbss_;
 308   // Offset of the GOT entry for the TLS module index;
 309   unsigned int got_mod_index_offset_;
 310 };
 311
 312 const Target::Target_info Target_x86_64::x86_64_info =
 313 {
 314   64,                   // size
 315   false,                // is_big_endian
 316   elfcpp::EM_X86_64,    // machine_code
 317   false,                // has_make_symbol
 318   false,                // has_resolve
 319   true,                 // has_code_fill
 320   true,                 // is_default_stack_executable
 321   "/lib/ld64.so.1",     // program interpreter
 322   0x400000,             // default_text_segment_address
 323   0x1000,               // abi_pagesize
 324   0x1000                // common_pagesize
 325 };
 326
 327 // Get the GOT section, creating it if necessary.
 328
 329 Output_data_got<64, false>*
 330 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 331 {
 332   if (this->got_ == NULL)
 333     {
 334       gold_assert(symtab != NULL && layout != NULL);
 335
 336       this->got_ = new Output_data_got<64, false>();
 337
 338       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 339                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 340                                       this->got_);
 341
 342       // The old GNU linker creates a .got.plt section.  We just
 343       // create another set of data in the .got section.  Note that we
 344       // always create a PLT if we create a GOT, although the PLT
 345       // might be empty.
 346       this->got_plt_ = new Output_data_space(8);
 347       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 348                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 349                                       this->got_plt_);
 350
 351       // The first three entries are reserved.
 352       this->got_plt_->set_current_data_size(3 * 8);
 353
 354       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 355       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 356                                     this->got_plt_,
 357                                     0, 0, elfcpp::STT_OBJECT,
 358                                     elfcpp::STB_LOCAL,
 359                                     elfcpp::STV_HIDDEN, 0,
 360                                     false, false);
 361     }
 362
 363   return this->got_;
 364 }
 365
 366 // Get the dynamic reloc section, creating it if necessary.
 367
 368 Target_x86_64::Reloc_section*
 369 Target_x86_64::rela_dyn_section(Layout* layout)
 370 {
 371   if (this->rela_dyn_ == NULL)
 372     {
 373       gold_assert(layout != NULL);
 374       this->rela_dyn_ = new Reloc_section();
 375       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 376                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 377     }
 378   return this->rela_dyn_;
 379 }
 380
 381 // A class to handle the PLT data.
 382
 383 class Output_data_plt_x86_64 : public Output_section_data
 384 {
 385  public:
 386   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 387
 388   Output_data_plt_x86_64(Layout*, Output_data_space*);
 389
 390   // Add an entry to the PLT.
 391   void
 392   add_entry(Symbol* gsym);
 393
 394   // Return the .rel.plt section data.
 395   const Reloc_section*
 396   rel_plt() const
 397   { return this->rel_; }
 398
 399  protected:
 400   void
 401   do_adjust_output_section(Output_section* os);
 402
 403  private:
 404   // The size of an entry in the PLT.
 405   static const int plt_entry_size = 16;
 406
 407   // The first entry in the PLT.
 408   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 409   // procedure linkage table for both programs and shared objects."
 410   static unsigned char first_plt_entry[plt_entry_size];
 411
 412   // Other entries in the PLT for an executable.
 413   static unsigned char plt_entry[plt_entry_size];
 414
 415   // Set the final size.
 416   void
 417   set_final_data_size()
 418   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 419
 420   // Write out the PLT data.
 421   void
 422   do_write(Output_file*);
 423
 424   // The reloc section.
 425   Reloc_section* rel_;
 426   // The .got.plt section.
 427   Output_data_space* got_plt_;
 428   // The number of PLT entries.
 429   unsigned int count_;
 430 };
 431
 432 // Create the PLT section.  The ordinary .got section is an argument,
 433 // since we need to refer to the start.  We also create our own .got
 434 // section just for PLT entries.
 435
 436 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 437                                                Output_data_space* got_plt)
 438   : Output_section_data(8), got_plt_(got_plt), count_(0)
 439 {
 440   this->rel_ = new Reloc_section();
 441   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 442                                   elfcpp::SHF_ALLOC, this->rel_);
 443 }
 444
 445 void
 446 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 447 {
 448   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 449   // linker, and so do we.
 450   os->set_entsize(4);
 451 }
 452
 453 // Add an entry to the PLT.
 454
 455 void
 456 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 457 {
 458   gold_assert(!gsym->has_plt_offset());
 459
 460   // Note that when setting the PLT offset we skip the initial
 461   // reserved PLT entry.
 462   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 463
 464   ++this->count_;
 465
 466   section_offset_type got_offset = this->got_plt_->current_data_size();
 467
 468   // Every PLT entry needs a GOT entry which points back to the PLT
 469   // entry (this will be changed by the dynamic linker, normally
 470   // lazily when the function is called).
 471   this->got_plt_->set_current_data_size(got_offset + 8);
 472
 473   // Every PLT entry needs a reloc.
 474   gsym->set_needs_dynsym_entry();
 475   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 476                          got_offset, 0);
 477
 478   // Note that we don't need to save the symbol.  The contents of the
 479   // PLT are independent of which symbols are used.  The symbols only
 480   // appear in the relocations.
 481 }
 482
 483 // The first entry in the PLT for an executable.
 484
 485 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 486 {
 487   // From AMD64 ABI Draft 0.98, page 76
 488   0xff, 0x35,   // pushq contents of memory address
 489   0, 0, 0, 0,   // replaced with address of .got + 8
 490   0xff, 0x25,   // jmp indirect
 491   0, 0, 0, 0,   // replaced with address of .got + 16
 492   0x90, 0x90, 0x90, 0x90   // noop (x4)
 493 };
 494
 495 // Subsequent entries in the PLT for an executable.
 496
 497 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 498 {
 499   // From AMD64 ABI Draft 0.98, page 76
 500   0xff, 0x25,   // jmpq indirect
 501   0, 0, 0, 0,   // replaced with address of symbol in .got
 502   0x68,         // pushq immediate
 503   0, 0, 0, 0,   // replaced with offset into relocation table
 504   0xe9,         // jmpq relative
 505   0, 0, 0, 0    // replaced with offset to start of .plt
 506 };
 507
 508 // Write out the PLT.  This uses the hand-coded instructions above,
 509 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 510
 511 void
 512 Output_data_plt_x86_64::do_write(Output_file* of)
 513 {
 514   const off_t offset = this->offset();
 515   const section_size_type oview_size =
 516     convert_to_section_size_type(this->data_size());
 517   unsigned char* const oview = of->get_output_view(offset, oview_size);
 518
 519   const off_t got_file_offset = this->got_plt_->offset();
 520   const section_size_type got_size =
 521     convert_to_section_size_type(this->got_plt_->data_size());
 522   unsigned char* const got_view = of->get_output_view(got_file_offset,
 523                                                       got_size);
 524
 525   unsigned char* pov = oview;
 526
 527   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 528   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 529
 530   memcpy(pov, first_plt_entry, plt_entry_size);
 531   // We do a jmp relative to the PC at the end of this instruction.
 532   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
 533                                               - (plt_address + 6));
 534   elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
 535                                     - (plt_address + 12));
 536   pov += plt_entry_size;
 537
 538   unsigned char* got_pov = got_view;
 539
 540   memset(got_pov, 0, 24);
 541   got_pov += 24;
 542
 543   unsigned int plt_offset = plt_entry_size;
 544   unsigned int got_offset = 24;
 545   const unsigned int count = this->count_;
 546   for (unsigned int plt_index = 0;
 547        plt_index < count;
 548        ++plt_index,
 549          pov += plt_entry_size,
 550          got_pov += 8,
 551          plt_offset += plt_entry_size,
 552          got_offset += 8)
 553     {
 554       // Set and adjust the PLT entry itself.
 555       memcpy(pov, plt_entry, plt_entry_size);
 556       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 557                                                   (got_address + got_offset
 558                                                    - (plt_address + plt_offset
 559                                                       + 6)));
 560
 561       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 562       elfcpp::Swap<32, false>::writeval(pov + 12,
 563                                         - (plt_offset + plt_entry_size));
 564
 565       // Set the entry in the GOT.
 566       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 567     }
 568
 569   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 570   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 571
 572   of->write_output_view(offset, oview_size, oview);
 573   of->write_output_view(got_file_offset, got_size, got_view);
 574 }
 575
 576 // Create a PLT entry for a global symbol.
 577
 578 void
 579 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 580                               Symbol* gsym)
 581 {
 582   if (gsym->has_plt_offset())
 583     return;
 584
 585   if (this->plt_ == NULL)
 586     {
 587       // Create the GOT sections first.
 588       this->got_section(symtab, layout);
 589
 590       this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_);
 591       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 592                                       (elfcpp::SHF_ALLOC
 593                                        | elfcpp::SHF_EXECINSTR),
 594                                       this->plt_);
 595     }
 596
 597   this->plt_->add_entry(gsym);
 598 }
 599
 600 // Create a GOT entry for the TLS module index.
 601
 602 unsigned int
 603 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 604                                    Sized_relobj<64, false>* object)
 605 {
 606   if (this->got_mod_index_offset_ == -1U)
 607     {
 608       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 609       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 610       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 611       unsigned int got_offset = got->add_constant(0);
 612       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 613                           got_offset, 0);
 614       got->add_constant(0);
 615       this->got_mod_index_offset_ = got_offset;
 616     }
 617   return this->got_mod_index_offset_;
 618 }
 619
 620 // Handle a relocation against a non-function symbol defined in a
 621 // dynamic object.  The traditional way to handle this is to generate
 622 // a COPY relocation to copy the variable at runtime from the shared
 623 // object into the executable's data segment.  However, this is
 624 // undesirable in general, as if the size of the object changes in the
 625 // dynamic object, the executable will no longer work correctly.  If
 626 // this relocation is in a writable section, then we can create a
 627 // dynamic reloc and the dynamic linker will resolve it to the correct
 628 // address at runtime.  However, we do not want do that if the
 629 // relocation is in a read-only section, as it would prevent the
 630 // readonly segment from being shared.  And if we have to eventually
 631 // generate a COPY reloc, then any dynamic relocations will be
 632 // useless.  So this means that if this is a writable section, we need
 633 // to save the relocation until we see whether we have to create a
 634 // COPY relocation for this symbol for any other relocation.
 635
 636 void
 637 Target_x86_64::copy_reloc(const General_options* options,
 638                           Symbol_table* symtab,
 639                           Layout* layout,
 640                           Sized_relobj<64, false>* object,
 641                           unsigned int data_shndx,
 642                           Output_section* output_section,
 643                           Symbol* gsym,
 644                           const elfcpp::Rela<64, false>& rela)
 645 {
 646   Sized_symbol<64>* ssym;
 647   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(64) (gsym
 648                                                         SELECT_SIZE(64));
 649
 650   if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
 651                                                data_shndx, ssym))
 652     {
 653       // So far we do not need a COPY reloc.  Save this relocation.
 654       // If it turns out that we never need a COPY reloc for this
 655       // symbol, then we will emit the relocation.
 656       if (this->copy_relocs_ == NULL)
 657         this->copy_relocs_ = new Copy_relocs<64, false>();
 658       this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
 659     }
 660   else
 661     {
 662       // Allocate space for this symbol in the .bss section.
 663
 664       elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
 665
 666       // There is no defined way to determine the required alignment
 667       // of the symbol.  We pick the alignment based on the size.  We
 668       // set an arbitrary maximum of 256.
 669       unsigned int align;
 670       for (align = 1; align < 512; align <<= 1)
 671         if ((symsize & align) != 0)
 672           break;
 673
 674       if (this->dynbss_ == NULL)
 675         {
 676           this->dynbss_ = new Output_data_space(align);
 677           layout->add_output_section_data(".bss",
 678                                           elfcpp::SHT_NOBITS,
 679                                           (elfcpp::SHF_ALLOC
 680                                            | elfcpp::SHF_WRITE),
 681                                           this->dynbss_);
 682         }
 683
 684       Output_data_space* dynbss = this->dynbss_;
 685
 686       if (align > dynbss->addralign())
 687         dynbss->set_space_alignment(align);
 688
 689       section_size_type dynbss_size = dynbss->current_data_size();
 690       dynbss_size = align_address(dynbss_size, align);
 691       section_size_type offset = dynbss_size;
 692       dynbss->set_current_data_size(dynbss_size + symsize);
 693
 694       symtab->define_with_copy_reloc(ssym, dynbss, offset);
 695
 696       // Add the COPY reloc.
 697       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 698       rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
 699     }
 700 }
 701
 702
 703 // Optimize the TLS relocation type based on what we know about the
 704 // symbol.  IS_FINAL is true if the final address of this symbol is
 705 // known at link time.
 706
 707 tls::Tls_optimization
 708 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 709 {
 710   // If we are generating a shared library, then we can't do anything
 711   // in the linker.
 712   if (parameters->output_is_shared())
 713     return tls::TLSOPT_NONE;
 714
 715   switch (r_type)
 716     {
 717     case elfcpp::R_X86_64_TLSGD:
 718     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 719     case elfcpp::R_X86_64_TLSDESC_CALL:
 720       // These are General-Dynamic which permits fully general TLS
 721       // access.  Since we know that we are generating an executable,
 722       // we can convert this to Initial-Exec.  If we also know that
 723       // this is a local symbol, we can further switch to Local-Exec.
 724       if (is_final)
 725         return tls::TLSOPT_TO_LE;
 726       return tls::TLSOPT_TO_IE;
 727
 728     case elfcpp::R_X86_64_TLSLD:
 729       // This is Local-Dynamic, which refers to a local symbol in the
 730       // dynamic TLS block.  Since we know that we generating an
 731       // executable, we can switch to Local-Exec.
 732       return tls::TLSOPT_TO_LE;
 733
 734     case elfcpp::R_X86_64_DTPOFF32:
 735     case elfcpp::R_X86_64_DTPOFF64:
 736       // Another Local-Dynamic reloc.
 737       return tls::TLSOPT_TO_LE;
 738
 739     case elfcpp::R_X86_64_GOTTPOFF:
 740       // These are Initial-Exec relocs which get the thread offset
 741       // from the GOT.  If we know that we are linking against the
 742       // local symbol, we can switch to Local-Exec, which links the
 743       // thread offset into the instruction.
 744       if (is_final)
 745         return tls::TLSOPT_TO_LE;
 746       return tls::TLSOPT_NONE;
 747
 748     case elfcpp::R_X86_64_TPOFF32:
 749       // When we already have Local-Exec, there is nothing further we
 750       // can do.
 751       return tls::TLSOPT_NONE;
 752
 753     default:
 754       gold_unreachable();
 755     }
 756 }
 757
 758 // Report an unsupported relocation against a local symbol.
 759
 760 void
 761 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 762                                              unsigned int r_type)
 763 {
 764   gold_error(_("%s: unsupported reloc %u against local symbol"),
 765              object->name().c_str(), r_type);
 766 }
 767
 768 // Scan a relocation for a local symbol.
 769
 770 inline void
 771 Target_x86_64::Scan::local(const General_options&,
 772                            Symbol_table* symtab,
 773                            Layout* layout,
 774                            Target_x86_64* target,
 775                            Sized_relobj<64, false>* object,
 776                            unsigned int data_shndx,
 777                            Output_section* output_section,
 778                            const elfcpp::Rela<64, false>& reloc,
 779                            unsigned int r_type,
 780                            const elfcpp::Sym<64, false>& lsym)
 781 {
 782   switch (r_type)
 783     {
 784     case elfcpp::R_X86_64_NONE:
 785     case elfcpp::R_386_GNU_VTINHERIT:
 786     case elfcpp::R_386_GNU_VTENTRY:
 787       break;
 788
 789     case elfcpp::R_X86_64_64:
 790       // If building a shared library (or a position-independent
 791       // executable), we need to create a dynamic relocation for
 792       // this location. The relocation applied at link time will
 793       // apply the link-time value, so we flag the location with
 794       // an R_386_RELATIVE relocation so the dynamic loader can
 795       // relocate it easily.
 796       if (parameters->output_is_position_independent())
 797         {
 798           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 799           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 800           rela_dyn->add_local_relative(object, r_sym,
 801                                        elfcpp::R_X86_64_RELATIVE,
 802                                        output_section, data_shndx,
 803                                        reloc.get_r_offset(),
 804                                        reloc.get_r_addend());
 805         }
 806       break;
 807
 808     case elfcpp::R_X86_64_32:
 809     case elfcpp::R_X86_64_32S:
 810     case elfcpp::R_X86_64_16:
 811     case elfcpp::R_X86_64_8:
 812       // If building a shared library (or a position-independent
 813       // executable), we need to create a dynamic relocation for
 814       // this location. The relocation applied at link time will
 815       // apply the link-time value, so we flag the location with
 816       // an R_386_RELATIVE relocation so the dynamic loader can
 817       // relocate it easily.
 818       if (parameters->output_is_position_independent())
 819         {
 820           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 821           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 822           rela_dyn->add_local(object, r_sym, r_type, output_section,
 823                               data_shndx, reloc.get_r_offset(),
 824                               reloc.get_r_addend());
 825         }
 826       break;
 827
 828     case elfcpp::R_X86_64_PC64:
 829     case elfcpp::R_X86_64_PC32:
 830     case elfcpp::R_X86_64_PC16:
 831     case elfcpp::R_X86_64_PC8:
 832       break;
 833
 834     case elfcpp::R_X86_64_PLT32:
 835       // Since we know this is a local symbol, we can handle this as a
 836       // PC32 reloc.
 837       break;
 838
 839     case elfcpp::R_X86_64_GOTPC32:
 840     case elfcpp::R_X86_64_GOTOFF64:
 841     case elfcpp::R_X86_64_GOTPC64:
 842     case elfcpp::R_X86_64_PLTOFF64:
 843       // We need a GOT section.
 844       target->got_section(symtab, layout);
 845       // For PLTOFF64, we'd normally want a PLT section, but since we
 846       // know this is a local symbol, no PLT is needed.
 847       break;
 848
 849     case elfcpp::R_X86_64_GOT64:
 850     case elfcpp::R_X86_64_GOT32:
 851     case elfcpp::R_X86_64_GOTPCREL64:
 852     case elfcpp::R_X86_64_GOTPCREL:
 853     case elfcpp::R_X86_64_GOTPLT64:
 854       {
 855         // The symbol requires a GOT entry.
 856         Output_data_got<64, false>* got = target->got_section(symtab, layout);
 857         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 858         if (got->add_local(object, r_sym))
 859           {
 860             // If we are generating a shared object, we need to add a
 861             // dynamic relocation for this symbol's GOT entry.
 862             if (parameters->output_is_position_independent())
 863               {
 864                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 865                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
 866                 if (r_type != elfcpp::R_X86_64_GOT32)
 867                   rela_dyn->add_local_relative(object, r_sym,
 868                                                elfcpp::R_X86_64_RELATIVE, got,
 869                                                object->local_got_offset(r_sym),
 870                                                0);
 871                 else
 872                   rela_dyn->add_local(object, r_sym, r_type,
 873                                       got, object->local_got_offset(r_sym), 0);
 874               }
 875           }
 876         // For GOTPLT64, we'd normally want a PLT section, but since
 877         // we know this is a local symbol, no PLT is needed.
 878       }
 879       break;
 880
 881     case elfcpp::R_X86_64_COPY:
 882     case elfcpp::R_X86_64_GLOB_DAT:
 883     case elfcpp::R_X86_64_JUMP_SLOT:
 884     case elfcpp::R_X86_64_RELATIVE:
 885       // These are outstanding tls relocs, which are unexpected when linking
 886     case elfcpp::R_X86_64_TPOFF64:
 887     case elfcpp::R_X86_64_DTPMOD64:
 888     case elfcpp::R_X86_64_TLSDESC:
 889       gold_error(_("%s: unexpected reloc %u in object file"),
 890                  object->name().c_str(), r_type);
 891       break;
 892
 893       // These are initial tls relocs, which are expected when linking
 894     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
 895     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
 896     case elfcpp::R_X86_64_TLSDESC_CALL:
 897     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
 898     case elfcpp::R_X86_64_DTPOFF32:
 899     case elfcpp::R_X86_64_DTPOFF64:
 900     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
 901     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
 902       {
 903         bool output_is_shared = parameters->output_is_shared();
 904         const tls::Tls_optimization optimized_type
 905             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
 906         switch (r_type)
 907           {
 908           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
 909             if (optimized_type == tls::TLSOPT_NONE)
 910               {
 911                 // Create a pair of GOT entries for the module index and
 912                 // dtv-relative offset.
 913                 Output_data_got<64, false>* got
 914                     = target->got_section(symtab, layout);
 915                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 916                 got->add_local_tls_with_rela(object, r_sym,
 917                                              lsym.get_st_shndx(), true,
 918                                              target->rela_dyn_section(layout),
 919                                              elfcpp::R_X86_64_DTPMOD64);
 920               }
 921             else if (optimized_type != tls::TLSOPT_TO_LE)
 922               unsupported_reloc_local(object, r_type);
 923             break;
 924
 925           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 926           case elfcpp::R_X86_64_TLSDESC_CALL:
 927             // FIXME: If not relaxing to LE, we need to generate
 928             // a GOT entry with a R_x86_64_TLSDESC reloc.
 929             if (optimized_type != tls::TLSOPT_TO_LE)
 930               unsupported_reloc_local(object, r_type);
 931             break;
 932
 933           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
 934             if (optimized_type == tls::TLSOPT_NONE)
 935               {
 936                 // Create a GOT entry for the module index.
 937                 target->got_mod_index_entry(symtab, layout, object);
 938               }
 939             else if (optimized_type != tls::TLSOPT_TO_LE)
 940               unsupported_reloc_local(object, r_type);
 941             break;
 942
 943           case elfcpp::R_X86_64_DTPOFF32:
 944           case elfcpp::R_X86_64_DTPOFF64:
 945             break;
 946
 947           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
 948             layout->set_has_static_tls();
 949             if (optimized_type == tls::TLSOPT_NONE)
 950               {
 951                 // Create a GOT entry for the tp-relative offset.
 952                 Output_data_got<64, false>* got
 953                     = target->got_section(symtab, layout);
 954                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 955                 got->add_local_with_rela(object, r_sym,
 956                                          target->rela_dyn_section(layout),
 957                                          elfcpp::R_X86_64_TPOFF64);
 958               }
 959             else if (optimized_type != tls::TLSOPT_TO_LE)
 960               unsupported_reloc_local(object, r_type);
 961             break;
 962
 963           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
 964             layout->set_has_static_tls();
 965             if (output_is_shared)
 966               unsupported_reloc_local(object, r_type);
 967             break;
 968
 969           default:
 970             gold_unreachable();
 971           }
 972       }
 973       break;
 974
 975     case elfcpp::R_X86_64_SIZE32:
 976     case elfcpp::R_X86_64_SIZE64:
 977     default:
 978       gold_error(_("%s: unsupported reloc %u against local symbol"),
 979                  object->name().c_str(), r_type);
 980       break;
 981     }
 982 }
 983
 984
 985 // Report an unsupported relocation against a global symbol.
 986
 987 void
 988 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
 989                                               unsigned int r_type,
 990                                               Symbol* gsym)
 991 {
 992   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
 993              object->name().c_str(), r_type, gsym->demangled_name().c_str());
 994 }
 995
 996 // Scan a relocation for a global symbol.
 997
 998 inline void
 999 Target_x86_64::Scan::global(const General_options& options,
1000                             Symbol_table* symtab,
1001                             Layout* layout,
1002                             Target_x86_64* target,
1003                             Sized_relobj<64, false>* object,
1004                             unsigned int data_shndx,
1005                             Output_section* output_section,
1006                             const elfcpp::Rela<64, false>& reloc,
1007                             unsigned int r_type,
1008                             Symbol* gsym)
1009 {
1010   switch (r_type)
1011     {
1012     case elfcpp::R_X86_64_NONE:
1013     case elfcpp::R_386_GNU_VTINHERIT:
1014     case elfcpp::R_386_GNU_VTENTRY:
1015       break;
1016
1017     case elfcpp::R_X86_64_64:
1018     case elfcpp::R_X86_64_32:
1019     case elfcpp::R_X86_64_32S:
1020     case elfcpp::R_X86_64_16:
1021     case elfcpp::R_X86_64_8:
1022       {
1023         // Make a PLT entry if necessary.
1024         if (gsym->needs_plt_entry())
1025           {
1026             target->make_plt_entry(symtab, layout, gsym);
1027             // Since this is not a PC-relative relocation, we may be
1028             // taking the address of a function. In that case we need to
1029             // set the entry in the dynamic symbol table to the address of
1030             // the PLT entry.
1031             if (gsym->is_from_dynobj() && !parameters->output_is_shared())
1032               gsym->set_needs_dynsym_value();
1033           }
1034         // Make a dynamic relocation if necessary.
1035         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1036           {
1037             if (target->may_need_copy_reloc(gsym))
1038               {
1039                 target->copy_reloc(&options, symtab, layout, object,
1040                                    data_shndx, output_section, gsym, reloc);
1041               }
1042             else if (r_type == elfcpp::R_X86_64_64
1043                      && gsym->can_use_relative_reloc(false))
1044               {
1045                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1046                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1047                                               output_section, object,
1048                                               data_shndx, reloc.get_r_offset(),
1049                                               reloc.get_r_addend());
1050               }
1051             else
1052               {
1053                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1054                 rela_dyn->add_global(gsym, r_type, output_section, object,
1055                                      data_shndx, reloc.get_r_offset(),
1056                                      reloc.get_r_addend());
1057               }
1058           }
1059       }
1060       break;
1061
1062     case elfcpp::R_X86_64_PC64:
1063     case elfcpp::R_X86_64_PC32:
1064     case elfcpp::R_X86_64_PC16:
1065     case elfcpp::R_X86_64_PC8:
1066       {
1067         // Make a PLT entry if necessary.
1068         if (gsym->needs_plt_entry())
1069           target->make_plt_entry(symtab, layout, gsym);
1070         // Make a dynamic relocation if necessary.
1071         int flags = Symbol::NON_PIC_REF;
1072         if (gsym->type() == elfcpp::STT_FUNC)
1073           flags |= Symbol::FUNCTION_CALL;
1074         if (gsym->needs_dynamic_reloc(flags))
1075           {
1076             if (target->may_need_copy_reloc(gsym))
1077               {
1078                 target->copy_reloc(&options, symtab, layout, object,
1079                                    data_shndx, output_section, gsym, reloc);
1080               }
1081             else
1082               {
1083                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1084                 rela_dyn->add_global(gsym, r_type, output_section, object,
1085                                      data_shndx, reloc.get_r_offset(),
1086                                      reloc.get_r_addend());
1087               }
1088           }
1089       }
1090       break;
1091
1092     case elfcpp::R_X86_64_GOT64:
1093     case elfcpp::R_X86_64_GOT32:
1094     case elfcpp::R_X86_64_GOTPCREL64:
1095     case elfcpp::R_X86_64_GOTPCREL:
1096     case elfcpp::R_X86_64_GOTPLT64:
1097       {
1098         // The symbol requires a GOT entry.
1099         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1100         if (gsym->final_value_is_known())
1101           got->add_global(gsym);
1102         else
1103           {
1104             // If this symbol is not fully resolved, we need to add a
1105             // dynamic relocation for it.
1106             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1107             if (gsym->is_from_dynobj() || gsym->is_preemptible())
1108               got->add_global_with_rela(gsym, rela_dyn,
1109                                         elfcpp::R_X86_64_GLOB_DAT);
1110             else
1111               {
1112                 if (got->add_global(gsym))
1113                   rela_dyn->add_global_relative(gsym,
1114                                                 elfcpp::R_X86_64_RELATIVE,
1115                                                 got, gsym->got_offset(), 0);
1116               }
1117           }
1118         // For GOTPLT64, we also need a PLT entry (but only if the
1119         // symbol is not fully resolved).
1120         if (r_type == elfcpp::R_X86_64_GOTPLT64
1121             && !gsym->final_value_is_known())
1122           target->make_plt_entry(symtab, layout, gsym);
1123       }
1124       break;
1125
1126     case elfcpp::R_X86_64_PLT32:
1127       // If the symbol is fully resolved, this is just a PC32 reloc.
1128       // Otherwise we need a PLT entry.
1129       if (gsym->final_value_is_known())
1130         break;
1131       // If building a shared library, we can also skip the PLT entry
1132       // if the symbol is defined in the output file and is protected
1133       // or hidden.
1134       if (gsym->is_defined()
1135           && !gsym->is_from_dynobj()
1136           && !gsym->is_preemptible())
1137         break;
1138       target->make_plt_entry(symtab, layout, gsym);
1139       break;
1140
1141     case elfcpp::R_X86_64_GOTPC32:
1142     case elfcpp::R_X86_64_GOTOFF64:
1143     case elfcpp::R_X86_64_GOTPC64:
1144     case elfcpp::R_X86_64_PLTOFF64:
1145       // We need a GOT section.
1146       target->got_section(symtab, layout);
1147       // For PLTOFF64, we also need a PLT entry (but only if the
1148       // symbol is not fully resolved).
1149       if (r_type == elfcpp::R_X86_64_PLTOFF64
1150           && !gsym->final_value_is_known())
1151         target->make_plt_entry(symtab, layout, gsym);
1152       break;
1153
1154     case elfcpp::R_X86_64_COPY:
1155     case elfcpp::R_X86_64_GLOB_DAT:
1156     case elfcpp::R_X86_64_JUMP_SLOT:
1157     case elfcpp::R_X86_64_RELATIVE:
1158       // These are outstanding tls relocs, which are unexpected when linking
1159     case elfcpp::R_X86_64_TPOFF64:
1160     case elfcpp::R_X86_64_DTPMOD64:
1161     case elfcpp::R_X86_64_TLSDESC:
1162       gold_error(_("%s: unexpected reloc %u in object file"),
1163                  object->name().c_str(), r_type);
1164       break;
1165
1166       // These are initial tls relocs, which are expected for global()
1167     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1168     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1169     case elfcpp::R_X86_64_TLSDESC_CALL:
1170     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1171     case elfcpp::R_X86_64_DTPOFF32:
1172     case elfcpp::R_X86_64_DTPOFF64:
1173     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1174     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1175       {
1176         const bool is_final = gsym->final_value_is_known();
1177         const tls::Tls_optimization optimized_type
1178             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1179         switch (r_type)
1180           {
1181           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1182             if (optimized_type == tls::TLSOPT_NONE)
1183               {
1184                 // Create a pair of GOT entries for the module index and
1185                 // dtv-relative offset.
1186                 Output_data_got<64, false>* got
1187                     = target->got_section(symtab, layout);
1188                 got->add_global_tls_with_rela(gsym,
1189                                               target->rela_dyn_section(layout),
1190                                               elfcpp::R_X86_64_DTPMOD64,
1191                                               elfcpp::R_X86_64_DTPOFF64);
1192               }
1193             else if (optimized_type == tls::TLSOPT_TO_IE)
1194               {
1195                 // Create a GOT entry for the tp-relative offset.
1196                 Output_data_got<64, false>* got
1197                     = target->got_section(symtab, layout);
1198                 got->add_global_with_rela(gsym,
1199                                           target->rela_dyn_section(layout),
1200                                           elfcpp::R_X86_64_TPOFF64);
1201               }
1202             else if (optimized_type != tls::TLSOPT_TO_LE)
1203               unsupported_reloc_global(object, r_type, gsym);
1204             break;
1205
1206           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1207           case elfcpp::R_X86_64_TLSDESC_CALL:
1208             // FIXME: If not relaxing to LE, we need to generate
1209             // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1210             if (optimized_type != tls::TLSOPT_TO_LE)
1211               unsupported_reloc_global(object, r_type, gsym);
1212             break;
1213
1214           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1215             if (optimized_type == tls::TLSOPT_NONE)
1216               {
1217                 // Create a GOT entry for the module index.
1218                 target->got_mod_index_entry(symtab, layout, object);
1219               }
1220             else if (optimized_type != tls::TLSOPT_TO_LE)
1221               unsupported_reloc_global(object, r_type, gsym);
1222             break;
1223
1224           case elfcpp::R_X86_64_DTPOFF32:
1225           case elfcpp::R_X86_64_DTPOFF64:
1226             break;
1227
1228           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1229             layout->set_has_static_tls();
1230             if (optimized_type == tls::TLSOPT_NONE)
1231               {
1232                 // Create a GOT entry for the tp-relative offset.
1233                 Output_data_got<64, false>* got
1234                     = target->got_section(symtab, layout);
1235                 got->add_global_with_rela(gsym,
1236                                           target->rela_dyn_section(layout),
1237                                           elfcpp::R_X86_64_TPOFF64);
1238               }
1239             else if (optimized_type != tls::TLSOPT_TO_LE)
1240               unsupported_reloc_global(object, r_type, gsym);
1241             break;
1242
1243           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1244             layout->set_has_static_tls();
1245             if (parameters->output_is_shared())
1246               unsupported_reloc_local(object, r_type);
1247             break;
1248
1249           default:
1250             gold_unreachable();
1251           }
1252       }
1253       break;
1254
1255     case elfcpp::R_X86_64_SIZE32:
1256     case elfcpp::R_X86_64_SIZE64:
1257     default:
1258       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1259                  object->name().c_str(), r_type,
1260                  gsym->demangled_name().c_str());
1261       break;
1262     }
1263 }
1264
1265 // Scan relocations for a section.
1266
1267 void
1268 Target_x86_64::scan_relocs(const General_options& options,
1269                            Symbol_table* symtab,
1270                            Layout* layout,
1271                            Sized_relobj<64, false>* object,
1272                            unsigned int data_shndx,
1273                            unsigned int sh_type,
1274                            const unsigned char* prelocs,
1275                            size_t reloc_count,
1276                            Output_section* output_section,
1277                            bool needs_special_offset_handling,
1278                            size_t local_symbol_count,
1279                            const unsigned char* plocal_symbols)
1280 {
1281   if (sh_type == elfcpp::SHT_REL)
1282     {
1283       gold_error(_("%s: unsupported REL reloc section"),
1284                  object->name().c_str());
1285       return;
1286     }
1287
1288   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1289       Target_x86_64::Scan>(
1290     options,
1291     symtab,
1292     layout,
1293     this,
1294     object,
1295     data_shndx,
1296     prelocs,
1297     reloc_count,
1298     output_section,
1299     needs_special_offset_handling,
1300     local_symbol_count,
1301     plocal_symbols);
1302 }
1303
1304 // Finalize the sections.
1305
1306 void
1307 Target_x86_64::do_finalize_sections(Layout* layout)
1308 {
1309   // Fill in some more dynamic tags.
1310   Output_data_dynamic* const odyn = layout->dynamic_data();
1311   if (odyn != NULL)
1312     {
1313       if (this->got_plt_ != NULL)
1314         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1315
1316       if (this->plt_ != NULL)
1317         {
1318           const Output_data* od = this->plt_->rel_plt();
1319           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1320           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1321           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1322         }
1323
1324       if (this->rela_dyn_ != NULL)
1325         {
1326           const Output_data* od = this->rela_dyn_;
1327           odyn->add_section_address(elfcpp::DT_RELA, od);
1328           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1329           odyn->add_constant(elfcpp::DT_RELAENT,
1330                              elfcpp::Elf_sizes<64>::rela_size);
1331         }
1332
1333       if (!parameters->output_is_shared())
1334         {
1335           // The value of the DT_DEBUG tag is filled in by the dynamic
1336           // linker at run time, and used by the debugger.
1337           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1338         }
1339     }
1340
1341   // Emit any relocs we saved in an attempt to avoid generating COPY
1342   // relocs.
1343   if (this->copy_relocs_ == NULL)
1344     return;
1345   if (this->copy_relocs_->any_to_emit())
1346     {
1347       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1348       this->copy_relocs_->emit(rela_dyn);
1349     }
1350   delete this->copy_relocs_;
1351   this->copy_relocs_ = NULL;
1352 }
1353
1354 // Perform a relocation.
1355
1356 inline bool
1357 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1358                                   Target_x86_64* target,
1359                                   size_t relnum,
1360                                   const elfcpp::Rela<64, false>& rela,
1361                                   unsigned int r_type,
1362                                   const Sized_symbol<64>* gsym,
1363                                   const Symbol_value<64>* psymval,
1364                                   unsigned char* view,
1365                                   elfcpp::Elf_types<64>::Elf_Addr address,
1366                                   section_size_type view_size)
1367 {
1368   if (this->skip_call_tls_get_addr_)
1369     {
1370       if (r_type != elfcpp::R_X86_64_PLT32
1371           || gsym == NULL
1372           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1373         {
1374           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1375                                  _("missing expected TLS relocation"));
1376         }
1377       else
1378         {
1379           this->skip_call_tls_get_addr_ = false;
1380           return false;
1381         }
1382     }
1383
1384   // Pick the value to use for symbols defined in shared objects.
1385   Symbol_value<64> symval;
1386   if (gsym != NULL
1387       && (gsym->is_from_dynobj()
1388           || (parameters->output_is_shared()
1389               && gsym->is_preemptible()))
1390       && gsym->has_plt_offset())
1391     {
1392       symval.set_output_value(target->plt_section()->address()
1393                               + gsym->plt_offset());
1394       psymval = &symval;
1395     }
1396
1397   const Sized_relobj<64, false>* object = relinfo->object;
1398   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1399
1400   // Get the GOT offset if needed.
1401   // The GOT pointer points to the end of the GOT section.
1402   // We need to subtract the size of the GOT section to get
1403   // the actual offset to use in the relocation.
1404   bool have_got_offset = false;
1405   unsigned int got_offset = 0;
1406   switch (r_type)
1407     {
1408     case elfcpp::R_X86_64_GOT32:
1409     case elfcpp::R_X86_64_GOT64:
1410     case elfcpp::R_X86_64_GOTPLT64:
1411     case elfcpp::R_X86_64_GOTPCREL:
1412     case elfcpp::R_X86_64_GOTPCREL64:
1413       if (gsym != NULL)
1414         {
1415           gold_assert(gsym->has_got_offset());
1416           got_offset = gsym->got_offset() - target->got_size();
1417         }
1418       else
1419         {
1420           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1421           gold_assert(object->local_has_got_offset(r_sym));
1422           got_offset = object->local_got_offset(r_sym) - target->got_size();
1423         }
1424       have_got_offset = true;
1425       break;
1426
1427     default:
1428       break;
1429     }
1430
1431   switch (r_type)
1432     {
1433     case elfcpp::R_X86_64_NONE:
1434     case elfcpp::R_386_GNU_VTINHERIT:
1435     case elfcpp::R_386_GNU_VTENTRY:
1436       break;
1437
1438     case elfcpp::R_X86_64_64:
1439       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1440       break;
1441
1442     case elfcpp::R_X86_64_PC64:
1443       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1444                                               address);
1445       break;
1446
1447     case elfcpp::R_X86_64_32:
1448       // FIXME: we need to verify that value + addend fits into 32 bits:
1449       //    uint64_t x = value + addend;
1450       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1451       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1452       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1453       break;
1454
1455     case elfcpp::R_X86_64_32S:
1456       // FIXME: we need to verify that value + addend fits into 32 bits:
1457       //    int64_t x = value + addend;   // note this quantity is signed!
1458       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1459       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1460       break;
1461
1462     case elfcpp::R_X86_64_PC32:
1463       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1464                                               address);
1465       break;
1466
1467     case elfcpp::R_X86_64_16:
1468       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1469       break;
1470
1471     case elfcpp::R_X86_64_PC16:
1472       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1473                                               address);
1474       break;
1475
1476     case elfcpp::R_X86_64_8:
1477       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1478       break;
1479
1480     case elfcpp::R_X86_64_PC8:
1481       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1482                                              address);
1483       break;
1484
1485     case elfcpp::R_X86_64_PLT32:
1486       gold_assert(gsym == NULL
1487                   || gsym->has_plt_offset()
1488                   || gsym->final_value_is_known()
1489                   || (gsym->is_defined()
1490                       && !gsym->is_from_dynobj()
1491                       && !gsym->is_preemptible()));
1492       // Note: while this code looks the same as for R_X86_64_PC32, it
1493       // behaves differently because psymval was set to point to
1494       // the PLT entry, rather than the symbol, in Scan::global().
1495       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1496                                               address);
1497       break;
1498
1499     case elfcpp::R_X86_64_PLTOFF64:
1500       {
1501         gold_assert(gsym);
1502         gold_assert(gsym->has_plt_offset()
1503                     || gsym->final_value_is_known());
1504         elfcpp::Elf_types<64>::Elf_Addr got_address;
1505         got_address = target->got_section(NULL, NULL)->address();
1506         Relocate_functions<64, false>::rela64(view, object, psymval,
1507                                               addend - got_address);
1508       }
1509
1510     case elfcpp::R_X86_64_GOT32:
1511       gold_assert(have_got_offset);
1512       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1513       break;
1514
1515     case elfcpp::R_X86_64_GOTPC32:
1516       {
1517         gold_assert(gsym);
1518         elfcpp::Elf_types<64>::Elf_Addr value;
1519         value = target->got_plt_section()->address();
1520         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1521       }
1522       break;
1523
1524     case elfcpp::R_X86_64_GOT64:
1525       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1526       // Since we always add a PLT entry, this is equivalent.
1527     case elfcpp::R_X86_64_GOTPLT64:
1528       gold_assert(have_got_offset);
1529       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1530       break;
1531
1532     case elfcpp::R_X86_64_GOTPC64:
1533       {
1534         gold_assert(gsym);
1535         elfcpp::Elf_types<64>::Elf_Addr value;
1536         value = target->got_plt_section()->address();
1537         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1538       }
1539       break;
1540
1541     case elfcpp::R_X86_64_GOTOFF64:
1542       {
1543         elfcpp::Elf_types<64>::Elf_Addr value;
1544         value = (psymval->value(object, 0)
1545                  - target->got_plt_section()->address());
1546         Relocate_functions<64, false>::rela64(view, value, addend);
1547       }
1548       break;
1549
1550     case elfcpp::R_X86_64_GOTPCREL:
1551       {
1552         gold_assert(have_got_offset);
1553         elfcpp::Elf_types<64>::Elf_Addr value;
1554         value = target->got_plt_section()->address() + got_offset;
1555         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1556       }
1557       break;
1558
1559     case elfcpp::R_X86_64_GOTPCREL64:
1560       {
1561         gold_assert(have_got_offset);
1562         elfcpp::Elf_types<64>::Elf_Addr value;
1563         value = target->got_plt_section()->address() + got_offset;
1564         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1565       }
1566       break;
1567
1568     case elfcpp::R_X86_64_COPY:
1569     case elfcpp::R_X86_64_GLOB_DAT:
1570     case elfcpp::R_X86_64_JUMP_SLOT:
1571     case elfcpp::R_X86_64_RELATIVE:
1572       // These are outstanding tls relocs, which are unexpected when linking
1573     case elfcpp::R_X86_64_TPOFF64:
1574     case elfcpp::R_X86_64_DTPMOD64:
1575     case elfcpp::R_X86_64_TLSDESC:
1576       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1577                              _("unexpected reloc %u in object file"),
1578                              r_type);
1579       break;
1580
1581       // These are initial tls relocs, which are expected when linking
1582     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1583     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1584     case elfcpp::R_X86_64_TLSDESC_CALL:
1585     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1586     case elfcpp::R_X86_64_DTPOFF32:
1587     case elfcpp::R_X86_64_DTPOFF64:
1588     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1589     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1590       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1591                          view, address, view_size);
1592       break;
1593
1594     case elfcpp::R_X86_64_SIZE32:
1595     case elfcpp::R_X86_64_SIZE64:
1596     default:
1597       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1598                              _("unsupported reloc %u"),
1599                              r_type);
1600       break;
1601     }
1602
1603   return true;
1604 }
1605
1606 // Perform a TLS relocation.
1607
1608 inline void
1609 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1610                                       Target_x86_64* target,
1611                                       size_t relnum,
1612                                       const elfcpp::Rela<64, false>& rela,
1613                                       unsigned int r_type,
1614                                       const Sized_symbol<64>* gsym,
1615                                       const Symbol_value<64>* psymval,
1616                                       unsigned char* view,
1617                                       elfcpp::Elf_types<64>::Elf_Addr address,
1618                                       section_size_type view_size)
1619 {
1620   Output_segment* tls_segment = relinfo->layout->tls_segment();
1621
1622   const Sized_relobj<64, false>* object = relinfo->object;
1623   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1624
1625   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1626
1627   const bool is_final = (gsym == NULL
1628                          ? !parameters->output_is_position_independent()
1629                          : gsym->final_value_is_known());
1630   const tls::Tls_optimization optimized_type
1631       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1632   switch (r_type)
1633     {
1634     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1635     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1636     case elfcpp::R_X86_64_TLSDESC_CALL:
1637       if (optimized_type == tls::TLSOPT_TO_LE)
1638         {
1639           gold_assert(tls_segment != NULL);
1640           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1641                              rela, r_type, value, view,
1642                              view_size);
1643           break;
1644         }
1645       else
1646         {
1647           unsigned int got_offset;
1648           if (gsym != NULL)
1649             {
1650               gold_assert(gsym->has_tls_got_offset(true));
1651               got_offset = gsym->tls_got_offset(true) - target->got_size();
1652             }
1653           else
1654             {
1655               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1656               gold_assert(object->local_has_tls_got_offset(r_sym, true));
1657               got_offset = (object->local_tls_got_offset(r_sym, true)
1658                             - target->got_size());
1659             }
1660           if (optimized_type == tls::TLSOPT_TO_IE)
1661             {
1662               gold_assert(tls_segment != NULL);
1663               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
1664                                  got_offset, view, view_size);
1665               break;
1666             }
1667           else if (optimized_type == tls::TLSOPT_NONE)
1668             {
1669               // Relocate the field with the offset of the pair of GOT
1670               // entries.
1671               value = target->got_plt_section()->address() + got_offset;
1672               Relocate_functions<64, false>::pcrela32(view, value, addend,
1673                                                       address);
1674               break;
1675             }
1676         }
1677       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1678                              _("unsupported reloc %u"), r_type);
1679       break;
1680
1681     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1682       if (optimized_type == tls::TLSOPT_TO_LE)
1683         {
1684           gold_assert(tls_segment != NULL);
1685           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
1686                              value, view, view_size);
1687           break;
1688         }
1689       else if (optimized_type == tls::TLSOPT_NONE)
1690         {
1691           // Relocate the field with the offset of the GOT entry for
1692           // the module index.
1693           unsigned int got_offset;
1694           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
1695                         - target->got_size());
1696           value = target->got_plt_section()->address() + got_offset;
1697           Relocate_functions<64, false>::pcrela32(view, value, addend,
1698                                                   address);
1699           break;
1700         }
1701       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1702                              _("unsupported reloc %u"), r_type);
1703       break;
1704
1705     case elfcpp::R_X86_64_DTPOFF32:
1706       gold_assert(tls_segment != NULL);
1707       if (optimized_type == tls::TLSOPT_TO_LE)
1708         value -= tls_segment->memsz();
1709       Relocate_functions<64, false>::rela32(view, value, 0);
1710       break;
1711
1712     case elfcpp::R_X86_64_DTPOFF64:
1713       gold_assert(tls_segment != NULL);
1714       if (optimized_type == tls::TLSOPT_TO_LE)
1715         value -= tls_segment->memsz();
1716       Relocate_functions<64, false>::rela64(view, value, 0);
1717       break;
1718
1719     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1720       if (optimized_type == tls::TLSOPT_TO_LE)
1721         {
1722           gold_assert(tls_segment != NULL);
1723           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1724                                                 rela, r_type, value, view,
1725                                                 view_size);
1726           break;
1727         }
1728       else if (optimized_type == tls::TLSOPT_NONE)
1729         {
1730           // Relocate the field with the offset of the GOT entry for
1731           // the tp-relative offset of the symbol.
1732           unsigned int got_offset;
1733           if (gsym != NULL)
1734             {
1735               gold_assert(gsym->has_got_offset());
1736               got_offset = gsym->got_offset() - target->got_size();
1737             }
1738           else
1739             {
1740               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1741               gold_assert(object->local_has_got_offset(r_sym));
1742               got_offset = (object->local_got_offset(r_sym)
1743                             - target->got_size());
1744             }
1745           value = target->got_plt_section()->address() + got_offset;
1746           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1747           break;
1748         }
1749       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1750                              _("unsupported reloc type %u"),
1751                              r_type);
1752       break;
1753
1754     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1755       value -= tls_segment->memsz();
1756       Relocate_functions<64, false>::rela32(view, value, 0);
1757       break;
1758     }
1759 }
1760
1761 // Do a relocation in which we convert a TLS General-Dynamic to an
1762 // Initial-Exec.
1763
1764 inline void
1765 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
1766                                       size_t relnum,
1767                                       Output_segment* tls_segment,
1768                                       const elfcpp::Rela<64, false>& rela,
1769                                       unsigned int,
1770                                       elfcpp::Elf_types<64>::Elf_Addr value,
1771                                       unsigned char* view,
1772                                       section_size_type view_size)
1773 {
1774   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1775   // .word 0x6666; rex64; call __tls_get_addr
1776   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
1777
1778   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1779   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1780
1781   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1782                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1783   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1784                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1785
1786   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
1787
1788   value -= tls_segment->memsz();
1789   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1790
1791   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1792   // We can skip it.
1793   this->skip_call_tls_get_addr_ = true;
1794 }
1795
1796 // Do a relocation in which we convert a TLS General-Dynamic to a
1797 // Local-Exec.
1798
1799 inline void
1800 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
1801                                       size_t relnum,
1802                                       Output_segment* tls_segment,
1803                                       const elfcpp::Rela<64, false>& rela,
1804                                       unsigned int,
1805                                       elfcpp::Elf_types<64>::Elf_Addr value,
1806                                       unsigned char* view,
1807                                       section_size_type view_size)
1808 {
1809   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1810   // .word 0x6666; rex64; call __tls_get_addr
1811   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1812
1813   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1814   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1815
1816   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1817                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1818   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1819                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1820
1821   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1822
1823   value -= tls_segment->memsz();
1824   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1825
1826   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1827   // We can skip it.
1828   this->skip_call_tls_get_addr_ = true;
1829 }
1830
1831 inline void
1832 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
1833                                       size_t relnum,
1834                                       Output_segment*,
1835                                       const elfcpp::Rela<64, false>& rela,
1836                                       unsigned int,
1837                                       elfcpp::Elf_types<64>::Elf_Addr,
1838                                       unsigned char* view,
1839                                       section_size_type view_size)
1840 {
1841   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1842   // ... leq foo@dtpoff(%rax),%reg
1843   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1844
1845   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1846   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
1847
1848   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1849                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
1850
1851   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
1852
1853   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1854
1855   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1856   // We can skip it.
1857   this->skip_call_tls_get_addr_ = true;
1858 }
1859
1860 // Do a relocation in which we convert a TLS Initial-Exec to a
1861 // Local-Exec.
1862
1863 inline void
1864 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
1865                                       size_t relnum,
1866                                       Output_segment* tls_segment,
1867                                       const elfcpp::Rela<64, false>& rela,
1868                                       unsigned int,
1869                                       elfcpp::Elf_types<64>::Elf_Addr value,
1870                                       unsigned char* view,
1871                                       section_size_type view_size)
1872 {
1873   // We need to examine the opcodes to figure out which instruction we
1874   // are looking at.
1875
1876   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
1877   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
1878
1879   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1880   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
1881
1882   unsigned char op1 = view[-3];
1883   unsigned char op2 = view[-2];
1884   unsigned char op3 = view[-1];
1885   unsigned char reg = op3 >> 3;
1886
1887   if (op2 == 0x8b)
1888     {
1889       // movq
1890       if (op1 == 0x4c)
1891         view[-3] = 0x49;
1892       view[-2] = 0xc7;
1893       view[-1] = 0xc0 | reg;
1894     }
1895   else if (reg == 4)
1896     {
1897       // Special handling for %rsp.
1898       if (op1 == 0x4c)
1899         view[-3] = 0x49;
1900       view[-2] = 0x81;
1901       view[-1] = 0xc0 | reg;
1902     }
1903   else
1904     {
1905       // addq
1906       if (op1 == 0x4c)
1907         view[-3] = 0x4d;
1908       view[-2] = 0x8d;
1909       view[-1] = 0x80 | reg | (reg << 3);
1910     }
1911
1912   value -= tls_segment->memsz();
1913   Relocate_functions<64, false>::rela32(view, value, 0);
1914 }
1915
1916 // Relocate section data.
1917
1918 void
1919 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
1920                                 unsigned int sh_type,
1921                                 const unsigned char* prelocs,
1922                                 size_t reloc_count,
1923                                 Output_section* output_section,
1924                                 bool needs_special_offset_handling,
1925                                 unsigned char* view,
1926                                 elfcpp::Elf_types<64>::Elf_Addr address,
1927                                 section_size_type view_size)
1928 {
1929   gold_assert(sh_type == elfcpp::SHT_RELA);
1930
1931   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
1932                          Target_x86_64::Relocate>(
1933     relinfo,
1934     this,
1935     prelocs,
1936     reloc_count,
1937     output_section,
1938     needs_special_offset_handling,
1939     view,
1940     address,
1941     view_size);
1942 }
1943
1944 // Return the value to use for a dynamic which requires special
1945 // treatment.  This is how we support equality comparisons of function
1946 // pointers across shared library boundaries, as described in the
1947 // processor specific ABI supplement.
1948
1949 uint64_t
1950 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
1951 {
1952   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1953   return this->plt_section()->address() + gsym->plt_offset();
1954 }
1955
1956 // Return a string used to fill a code section with nops to take up
1957 // the specified length.
1958
1959 std::string
1960 Target_x86_64::do_code_fill(section_size_type length)
1961 {
1962   if (length >= 16)
1963     {
1964       // Build a jmpq instruction to skip over the bytes.
1965       unsigned char jmp[5];
1966       jmp[0] = 0xe9;
1967       elfcpp::Swap_unaligned<64, false>::writeval(jmp + 1, length - 5);
1968       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1969               + std::string(length - 5, '\0'));
1970     }
1971
1972   // Nop sequences of various lengths.
1973   const char nop1[1] = { 0x90 };                   // nop
1974   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1975   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1976   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1977   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1978                          0x00 };                   // leal 0(%esi,1),%esi
1979   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1980                          0x00, 0x00 };
1981   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1982                          0x00, 0x00, 0x00 };
1983   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1984                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1985   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1986                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1987                          0x00 };
1988   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1989                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1990                            0x00, 0x00 };
1991   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1992                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1993                            0x00, 0x00, 0x00 };
1994   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1995                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1996                            0x00, 0x00, 0x00, 0x00 };
1997   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1998                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1999                            0x27, 0x00, 0x00, 0x00,
2000                            0x00 };
2001   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2002                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2003                            0xbc, 0x27, 0x00, 0x00,
2004                            0x00, 0x00 };
2005   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2006                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2007                            0x90, 0x90, 0x90, 0x90,
2008                            0x90, 0x90, 0x90 };
2009
2010   const char* nops[16] = {
2011     NULL,
2012     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2013     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2014   };
2015
2016   return std::string(nops[length], length);
2017 }
2018
2019 // The selector for x86_64 object files.
2020
2021 class Target_selector_x86_64 : public Target_selector
2022 {
2023 public:
2024   Target_selector_x86_64()
2025     : Target_selector(elfcpp::EM_X86_64, 64, false)
2026   { }
2027
2028   Target*
2029   recognize(int machine, int osabi, int abiversion);
2030
2031  private:
2032   Target_x86_64* target_;
2033 };
2034
2035 // Recognize an x86_64 object file when we already know that the machine
2036 // number is EM_X86_64.
2037
2038 Target*
2039 Target_selector_x86_64::recognize(int, int, int)
2040 {
2041   if (this->target_ == NULL)
2042     this->target_ = new Target_x86_64();
2043   return this->target_;
2044 }
2045
2046 Target_selector_x86_64 target_selector_x86_64;
2047
2048 } // End anonymous namespace.