gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "parameters.h"
  29 #include "reloc.h"
  30 #include "x86_64.h"
  31 #include "object.h"
  32 #include "symtab.h"
  33 #include "layout.h"
  34 #include "output.h"
  35 #include "target.h"
  36 #include "target-reloc.h"
  37 #include "target-select.h"
  38 #include "tls.h"
  39
  40 namespace
  41 {
  42
  43 using namespace gold;
  44
  45 class Output_data_plt_x86_64;
  46
  47 // The x86_64 target class.
  48 // See the ABI at
  49 //   http://www.x86-64.org/documentation/abi.pdf
  50 // TLS info comes from
  51 //   http://people.redhat.com/drepper/tls.pdf
  52 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  53
  54 class Target_x86_64 : public Sized_target<64, false>
  55 {
  56  public:
  57   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
  58   // uses only Elf64_Rela relocation entries with explicit addends."
  59   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  60
  61   Target_x86_64()
  62     : Sized_target<64, false>(&x86_64_info),
  63       got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
  64       copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
  65   { }
  66
  67   // Scan the relocations to look for symbol adjustments.
  68   void
  69   scan_relocs(const General_options& options,
  70               Symbol_table* symtab,
  71               Layout* layout,
  72               Sized_relobj<64, false>* object,
  73               unsigned int data_shndx,
  74               unsigned int sh_type,
  75               const unsigned char* prelocs,
  76               size_t reloc_count,
  77               Output_section* output_section,
  78               bool needs_special_offset_handling,
  79               size_t local_symbol_count,
  80               const unsigned char* plocal_symbols);
  81
  82   // Finalize the sections.
  83   void
  84   do_finalize_sections(Layout*);
  85
  86   // Return the value to use for a dynamic which requires special
  87   // treatment.
  88   uint64_t
  89   do_dynsym_value(const Symbol*) const;
  90
  91   // Relocate a section.
  92   void
  93   relocate_section(const Relocate_info<64, false>*,
  94                    unsigned int sh_type,
  95                    const unsigned char* prelocs,
  96                    size_t reloc_count,
  97                    Output_section* output_section,
  98                    bool needs_special_offset_handling,
  99                    unsigned char* view,
 100                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 101                    section_size_type view_size);
 102
 103   // Scan the relocs during a relocatable link.
 104   void
 105   scan_relocatable_relocs(const General_options& options,
 106                           Symbol_table* symtab,
 107                           Layout* layout,
 108                           Sized_relobj<64, false>* object,
 109                           unsigned int data_shndx,
 110                           unsigned int sh_type,
 111                           const unsigned char* prelocs,
 112                           size_t reloc_count,
 113                           Output_section* output_section,
 114                           bool needs_special_offset_handling,
 115                           size_t local_symbol_count,
 116                           const unsigned char* plocal_symbols,
 117                           Relocatable_relocs*);
 118
 119   // Relocate a section during a relocatable link.
 120   void
 121   relocate_for_relocatable(const Relocate_info<64, false>*,
 122                            unsigned int sh_type,
 123                            const unsigned char* prelocs,
 124                            size_t reloc_count,
 125                            Output_section* output_section,
 126                            off_t offset_in_output_section,
 127                            const Relocatable_relocs*,
 128                            unsigned char* view,
 129                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 130                            section_size_type view_size,
 131                            unsigned char* reloc_view,
 132                            section_size_type reloc_view_size);
 133
 134   // Return a string used to fill a code section with nops.
 135   std::string
 136   do_code_fill(section_size_type length) const;
 137
 138   // Return whether SYM is defined by the ABI.
 139   bool
 140   do_is_defined_by_abi(Symbol* sym) const
 141   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 142
 143   // Return the size of the GOT section.
 144   section_size_type
 145   got_size()
 146   {
 147     gold_assert(this->got_ != NULL);
 148     return this->got_->data_size();
 149   }
 150
 151  private:
 152   // The class which scans relocations.
 153   class Scan
 154   {
 155   public:
 156     Scan()
 157       : issued_non_pic_error_(false)
 158     { }
 159
 160     inline void
 161     local(const General_options& options, Symbol_table* symtab,
 162           Layout* layout, Target_x86_64* target,
 163           Sized_relobj<64, false>* object,
 164           unsigned int data_shndx,
 165           Output_section* output_section,
 166           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 167           const elfcpp::Sym<64, false>& lsym);
 168
 169     inline void
 170     global(const General_options& options, Symbol_table* symtab,
 171            Layout* layout, Target_x86_64* target,
 172            Sized_relobj<64, false>* object,
 173            unsigned int data_shndx,
 174            Output_section* output_section,
 175            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 176            Symbol* gsym);
 177
 178   private:
 179     static void
 180     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 181
 182     static void
 183     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 184                              Symbol*);
 185
 186     void
 187     check_non_pic(Relobj*, unsigned int r_type);
 188
 189     // Whether we have issued an error about a non-PIC compilation.
 190     bool issued_non_pic_error_;
 191   };
 192
 193   // The class which implements relocation.
 194   class Relocate
 195   {
 196    public:
 197     Relocate()
 198       : skip_call_tls_get_addr_(false)
 199     { }
 200
 201     ~Relocate()
 202     {
 203       if (this->skip_call_tls_get_addr_)
 204         {
 205           // FIXME: This needs to specify the location somehow.
 206           gold_error(_("missing expected TLS relocation"));
 207         }
 208     }
 209
 210     // Do a relocation.  Return false if the caller should not issue
 211     // any warnings about this relocation.
 212     inline bool
 213     relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum,
 214              const elfcpp::Rela<64, false>&,
 215              unsigned int r_type, const Sized_symbol<64>*,
 216              const Symbol_value<64>*,
 217              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 218              section_size_type);
 219
 220    private:
 221     // Do a TLS relocation.
 222     inline void
 223     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 224                  size_t relnum, const elfcpp::Rela<64, false>&,
 225                  unsigned int r_type, const Sized_symbol<64>*,
 226                  const Symbol_value<64>*,
 227                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 228                  section_size_type);
 229
 230     // Do a TLS General-Dynamic to Local-Exec transition.
 231     inline void
 232     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 233                  Output_segment* tls_segment,
 234                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 235                  elfcpp::Elf_types<64>::Elf_Addr value,
 236                  unsigned char* view,
 237                  section_size_type view_size);
 238
 239     // Do a TLS General-Dynamic to Local-Exec transition.
 240     inline void
 241     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 242                  Output_segment* tls_segment,
 243                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 244                  elfcpp::Elf_types<64>::Elf_Addr value,
 245                  unsigned char* view,
 246                  section_size_type view_size);
 247
 248     // Do a TLS Local-Dynamic to Local-Exec transition.
 249     inline void
 250     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 251                  Output_segment* tls_segment,
 252                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 253                  elfcpp::Elf_types<64>::Elf_Addr value,
 254                  unsigned char* view,
 255                  section_size_type view_size);
 256
 257     // Do a TLS Initial-Exec to Local-Exec transition.
 258     static inline void
 259     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 260                  Output_segment* tls_segment,
 261                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 262                  elfcpp::Elf_types<64>::Elf_Addr value,
 263                  unsigned char* view,
 264                  section_size_type view_size);
 265
 266     // This is set if we should skip the next reloc, which should be a
 267     // PLT32 reloc against ___tls_get_addr.
 268     bool skip_call_tls_get_addr_;
 269   };
 270
 271   // A class which returns the size required for a relocation type,
 272   // used while scanning relocs during a relocatable link.
 273   class Relocatable_size_for_reloc
 274   {
 275    public:
 276     unsigned int
 277     get_size_for_reloc(unsigned int, Relobj*);
 278   };
 279
 280   // Adjust TLS relocation type based on the options and whether this
 281   // is a local symbol.
 282   static tls::Tls_optimization
 283   optimize_tls_reloc(bool is_final, int r_type);
 284
 285   // Get the GOT section, creating it if necessary.
 286   Output_data_got<64, false>*
 287   got_section(Symbol_table*, Layout*);
 288
 289   // Get the GOT PLT section.
 290   Output_data_space*
 291   got_plt_section() const
 292   {
 293     gold_assert(this->got_plt_ != NULL);
 294     return this->got_plt_;
 295   }
 296
 297   // Create a PLT entry for a global symbol.
 298   void
 299   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 300
 301   // Create a GOT entry for the TLS module index.
 302   unsigned int
 303   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 304                       Sized_relobj<64, false>* object);
 305
 306   // Get the PLT section.
 307   Output_data_plt_x86_64*
 308   plt_section() const
 309   {
 310     gold_assert(this->plt_ != NULL);
 311     return this->plt_;
 312   }
 313
 314   // Get the dynamic reloc section, creating it if necessary.
 315   Reloc_section*
 316   rela_dyn_section(Layout*);
 317
 318   // Return true if the symbol may need a COPY relocation.
 319   // References from an executable object to non-function symbols
 320   // defined in a dynamic object may need a COPY relocation.
 321   bool
 322   may_need_copy_reloc(Symbol* gsym)
 323   {
 324     return (!parameters->options().shared()
 325             && gsym->is_from_dynobj()
 326             && gsym->type() != elfcpp::STT_FUNC);
 327   }
 328
 329   // Copy a relocation against a global symbol.
 330   void
 331   copy_reloc(const General_options*, Symbol_table*, Layout*,
 332              Sized_relobj<64, false>*, unsigned int,
 333              Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
 334
 335   // Information about this specific target which we pass to the
 336   // general Target structure.
 337   static const Target::Target_info x86_64_info;
 338
 339   enum Got_type
 340   {
 341     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 342     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 343     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 344     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 345   };
 346
 347   // The GOT section.
 348   Output_data_got<64, false>* got_;
 349   // The PLT section.
 350   Output_data_plt_x86_64* plt_;
 351   // The GOT PLT section.
 352   Output_data_space* got_plt_;
 353   // The dynamic reloc section.
 354   Reloc_section* rela_dyn_;
 355   // Relocs saved to avoid a COPY reloc.
 356   Copy_relocs<64, false>* copy_relocs_;
 357   // Space for variables copied with a COPY reloc.
 358   Output_data_space* dynbss_;
 359   // Offset of the GOT entry for the TLS module index;
 360   unsigned int got_mod_index_offset_;
 361 };
 362
 363 const Target::Target_info Target_x86_64::x86_64_info =
 364 {
 365   64,                   // size
 366   false,                // is_big_endian
 367   elfcpp::EM_X86_64,    // machine_code
 368   false,                // has_make_symbol
 369   false,                // has_resolve
 370   true,                 // has_code_fill
 371   true,                 // is_default_stack_executable
 372   "/lib/ld64.so.1",     // program interpreter
 373   0x400000,             // default_text_segment_address
 374   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 375   0x1000                // common_pagesize (overridable by -z common-page-size)
 376 };
 377
 378 // Get the GOT section, creating it if necessary.
 379
 380 Output_data_got<64, false>*
 381 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 382 {
 383   if (this->got_ == NULL)
 384     {
 385       gold_assert(symtab != NULL && layout != NULL);
 386
 387       this->got_ = new Output_data_got<64, false>();
 388
 389       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 390                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 391                                       this->got_);
 392
 393       // The old GNU linker creates a .got.plt section.  We just
 394       // create another set of data in the .got section.  Note that we
 395       // always create a PLT if we create a GOT, although the PLT
 396       // might be empty.
 397       this->got_plt_ = new Output_data_space(8);
 398       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 399                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 400                                       this->got_plt_);
 401
 402       // The first three entries are reserved.
 403       this->got_plt_->set_current_data_size(3 * 8);
 404
 405       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 406       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 407                                     this->got_plt_,
 408                                     0, 0, elfcpp::STT_OBJECT,
 409                                     elfcpp::STB_LOCAL,
 410                                     elfcpp::STV_HIDDEN, 0,
 411                                     false, false);
 412     }
 413
 414   return this->got_;
 415 }
 416
 417 // Get the dynamic reloc section, creating it if necessary.
 418
 419 Target_x86_64::Reloc_section*
 420 Target_x86_64::rela_dyn_section(Layout* layout)
 421 {
 422   if (this->rela_dyn_ == NULL)
 423     {
 424       gold_assert(layout != NULL);
 425       this->rela_dyn_ = new Reloc_section();
 426       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 427                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 428     }
 429   return this->rela_dyn_;
 430 }
 431
 432 // A class to handle the PLT data.
 433
 434 class Output_data_plt_x86_64 : public Output_section_data
 435 {
 436  public:
 437   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 438
 439   Output_data_plt_x86_64(Layout*, Output_data_space*);
 440
 441   // Add an entry to the PLT.
 442   void
 443   add_entry(Symbol* gsym);
 444
 445   // Return the .rel.plt section data.
 446   const Reloc_section*
 447   rel_plt() const
 448   { return this->rel_; }
 449
 450  protected:
 451   void
 452   do_adjust_output_section(Output_section* os);
 453
 454  private:
 455   // The size of an entry in the PLT.
 456   static const int plt_entry_size = 16;
 457
 458   // The first entry in the PLT.
 459   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 460   // procedure linkage table for both programs and shared objects."
 461   static unsigned char first_plt_entry[plt_entry_size];
 462
 463   // Other entries in the PLT for an executable.
 464   static unsigned char plt_entry[plt_entry_size];
 465
 466   // Set the final size.
 467   void
 468   set_final_data_size()
 469   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 470
 471   // Write out the PLT data.
 472   void
 473   do_write(Output_file*);
 474
 475   // The reloc section.
 476   Reloc_section* rel_;
 477   // The .got.plt section.
 478   Output_data_space* got_plt_;
 479   // The number of PLT entries.
 480   unsigned int count_;
 481 };
 482
 483 // Create the PLT section.  The ordinary .got section is an argument,
 484 // since we need to refer to the start.  We also create our own .got
 485 // section just for PLT entries.
 486
 487 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 488                                                Output_data_space* got_plt)
 489   : Output_section_data(8), got_plt_(got_plt), count_(0)
 490 {
 491   this->rel_ = new Reloc_section();
 492   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 493                                   elfcpp::SHF_ALLOC, this->rel_);
 494 }
 495
 496 void
 497 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 498 {
 499   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 500   // linker, and so do we.
 501   os->set_entsize(4);
 502 }
 503
 504 // Add an entry to the PLT.
 505
 506 void
 507 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 508 {
 509   gold_assert(!gsym->has_plt_offset());
 510
 511   // Note that when setting the PLT offset we skip the initial
 512   // reserved PLT entry.
 513   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 514
 515   ++this->count_;
 516
 517   section_offset_type got_offset = this->got_plt_->current_data_size();
 518
 519   // Every PLT entry needs a GOT entry which points back to the PLT
 520   // entry (this will be changed by the dynamic linker, normally
 521   // lazily when the function is called).
 522   this->got_plt_->set_current_data_size(got_offset + 8);
 523
 524   // Every PLT entry needs a reloc.
 525   gsym->set_needs_dynsym_entry();
 526   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 527                          got_offset, 0);
 528
 529   // Note that we don't need to save the symbol.  The contents of the
 530   // PLT are independent of which symbols are used.  The symbols only
 531   // appear in the relocations.
 532 }
 533
 534 // The first entry in the PLT for an executable.
 535
 536 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 537 {
 538   // From AMD64 ABI Draft 0.98, page 76
 539   0xff, 0x35,   // pushq contents of memory address
 540   0, 0, 0, 0,   // replaced with address of .got + 8
 541   0xff, 0x25,   // jmp indirect
 542   0, 0, 0, 0,   // replaced with address of .got + 16
 543   0x90, 0x90, 0x90, 0x90   // noop (x4)
 544 };
 545
 546 // Subsequent entries in the PLT for an executable.
 547
 548 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 549 {
 550   // From AMD64 ABI Draft 0.98, page 76
 551   0xff, 0x25,   // jmpq indirect
 552   0, 0, 0, 0,   // replaced with address of symbol in .got
 553   0x68,         // pushq immediate
 554   0, 0, 0, 0,   // replaced with offset into relocation table
 555   0xe9,         // jmpq relative
 556   0, 0, 0, 0    // replaced with offset to start of .plt
 557 };
 558
 559 // Write out the PLT.  This uses the hand-coded instructions above,
 560 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 561
 562 void
 563 Output_data_plt_x86_64::do_write(Output_file* of)
 564 {
 565   const off_t offset = this->offset();
 566   const section_size_type oview_size =
 567     convert_to_section_size_type(this->data_size());
 568   unsigned char* const oview = of->get_output_view(offset, oview_size);
 569
 570   const off_t got_file_offset = this->got_plt_->offset();
 571   const section_size_type got_size =
 572     convert_to_section_size_type(this->got_plt_->data_size());
 573   unsigned char* const got_view = of->get_output_view(got_file_offset,
 574                                                       got_size);
 575
 576   unsigned char* pov = oview;
 577
 578   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 579   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 580
 581   memcpy(pov, first_plt_entry, plt_entry_size);
 582   // We do a jmp relative to the PC at the end of this instruction.
 583   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
 584                                               - (plt_address + 6));
 585   elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
 586                                     - (plt_address + 12));
 587   pov += plt_entry_size;
 588
 589   unsigned char* got_pov = got_view;
 590
 591   memset(got_pov, 0, 24);
 592   got_pov += 24;
 593
 594   unsigned int plt_offset = plt_entry_size;
 595   unsigned int got_offset = 24;
 596   const unsigned int count = this->count_;
 597   for (unsigned int plt_index = 0;
 598        plt_index < count;
 599        ++plt_index,
 600          pov += plt_entry_size,
 601          got_pov += 8,
 602          plt_offset += plt_entry_size,
 603          got_offset += 8)
 604     {
 605       // Set and adjust the PLT entry itself.
 606       memcpy(pov, plt_entry, plt_entry_size);
 607       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 608                                                   (got_address + got_offset
 609                                                    - (plt_address + plt_offset
 610                                                       + 6)));
 611
 612       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 613       elfcpp::Swap<32, false>::writeval(pov + 12,
 614                                         - (plt_offset + plt_entry_size));
 615
 616       // Set the entry in the GOT.
 617       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 618     }
 619
 620   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 621   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 622
 623   of->write_output_view(offset, oview_size, oview);
 624   of->write_output_view(got_file_offset, got_size, got_view);
 625 }
 626
 627 // Create a PLT entry for a global symbol.
 628
 629 void
 630 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 631                               Symbol* gsym)
 632 {
 633   if (gsym->has_plt_offset())
 634     return;
 635
 636   if (this->plt_ == NULL)
 637     {
 638       // Create the GOT sections first.
 639       this->got_section(symtab, layout);
 640
 641       this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_);
 642       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 643                                       (elfcpp::SHF_ALLOC
 644                                        | elfcpp::SHF_EXECINSTR),
 645                                       this->plt_);
 646     }
 647
 648   this->plt_->add_entry(gsym);
 649 }
 650
 651 // Create a GOT entry for the TLS module index.
 652
 653 unsigned int
 654 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 655                                    Sized_relobj<64, false>* object)
 656 {
 657   if (this->got_mod_index_offset_ == -1U)
 658     {
 659       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 660       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 661       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 662       unsigned int got_offset = got->add_constant(0);
 663       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 664                           got_offset, 0);
 665       got->add_constant(0);
 666       this->got_mod_index_offset_ = got_offset;
 667     }
 668   return this->got_mod_index_offset_;
 669 }
 670
 671 // Handle a relocation against a non-function symbol defined in a
 672 // dynamic object.  The traditional way to handle this is to generate
 673 // a COPY relocation to copy the variable at runtime from the shared
 674 // object into the executable's data segment.  However, this is
 675 // undesirable in general, as if the size of the object changes in the
 676 // dynamic object, the executable will no longer work correctly.  If
 677 // this relocation is in a writable section, then we can create a
 678 // dynamic reloc and the dynamic linker will resolve it to the correct
 679 // address at runtime.  However, we do not want do that if the
 680 // relocation is in a read-only section, as it would prevent the
 681 // readonly segment from being shared.  And if we have to eventually
 682 // generate a COPY reloc, then any dynamic relocations will be
 683 // useless.  So this means that if this is a writable section, we need
 684 // to save the relocation until we see whether we have to create a
 685 // COPY relocation for this symbol for any other relocation.
 686
 687 void
 688 Target_x86_64::copy_reloc(const General_options* options,
 689                           Symbol_table* symtab,
 690                           Layout* layout,
 691                           Sized_relobj<64, false>* object,
 692                           unsigned int data_shndx,
 693                           Output_section* output_section,
 694                           Symbol* gsym,
 695                           const elfcpp::Rela<64, false>& rela)
 696 {
 697   Sized_symbol<64>* ssym = symtab->get_sized_symbol<64>(gsym);
 698
 699   if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
 700                                                data_shndx, ssym))
 701     {
 702       // So far we do not need a COPY reloc.  Save this relocation.
 703       // If it turns out that we never need a COPY reloc for this
 704       // symbol, then we will emit the relocation.
 705       if (this->copy_relocs_ == NULL)
 706         this->copy_relocs_ = new Copy_relocs<64, false>();
 707       this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
 708     }
 709   else
 710     {
 711       // Allocate space for this symbol in the .bss section.
 712
 713       elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
 714
 715       // There is no defined way to determine the required alignment
 716       // of the symbol.  We pick the alignment based on the size.  We
 717       // set an arbitrary maximum of 256.
 718       unsigned int align;
 719       for (align = 1; align < 512; align <<= 1)
 720         if ((symsize & align) != 0)
 721           break;
 722
 723       if (this->dynbss_ == NULL)
 724         {
 725           this->dynbss_ = new Output_data_space(align);
 726           layout->add_output_section_data(".bss",
 727                                           elfcpp::SHT_NOBITS,
 728                                           (elfcpp::SHF_ALLOC
 729                                            | elfcpp::SHF_WRITE),
 730                                           this->dynbss_);
 731         }
 732
 733       Output_data_space* dynbss = this->dynbss_;
 734
 735       if (align > dynbss->addralign())
 736         dynbss->set_space_alignment(align);
 737
 738       section_size_type dynbss_size = dynbss->current_data_size();
 739       dynbss_size = align_address(dynbss_size, align);
 740       section_size_type offset = dynbss_size;
 741       dynbss->set_current_data_size(dynbss_size + symsize);
 742
 743       symtab->define_with_copy_reloc(ssym, dynbss, offset);
 744
 745       // Add the COPY reloc.
 746       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 747       rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
 748     }
 749 }
 750
 751
 752 // Optimize the TLS relocation type based on what we know about the
 753 // symbol.  IS_FINAL is true if the final address of this symbol is
 754 // known at link time.
 755
 756 tls::Tls_optimization
 757 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 758 {
 759   // If we are generating a shared library, then we can't do anything
 760   // in the linker.
 761   if (parameters->options().shared())
 762     return tls::TLSOPT_NONE;
 763
 764   switch (r_type)
 765     {
 766     case elfcpp::R_X86_64_TLSGD:
 767     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 768     case elfcpp::R_X86_64_TLSDESC_CALL:
 769       // These are General-Dynamic which permits fully general TLS
 770       // access.  Since we know that we are generating an executable,
 771       // we can convert this to Initial-Exec.  If we also know that
 772       // this is a local symbol, we can further switch to Local-Exec.
 773       if (is_final)
 774         return tls::TLSOPT_TO_LE;
 775       return tls::TLSOPT_TO_IE;
 776
 777     case elfcpp::R_X86_64_TLSLD:
 778       // This is Local-Dynamic, which refers to a local symbol in the
 779       // dynamic TLS block.  Since we know that we generating an
 780       // executable, we can switch to Local-Exec.
 781       return tls::TLSOPT_TO_LE;
 782
 783     case elfcpp::R_X86_64_DTPOFF32:
 784     case elfcpp::R_X86_64_DTPOFF64:
 785       // Another Local-Dynamic reloc.
 786       return tls::TLSOPT_TO_LE;
 787
 788     case elfcpp::R_X86_64_GOTTPOFF:
 789       // These are Initial-Exec relocs which get the thread offset
 790       // from the GOT.  If we know that we are linking against the
 791       // local symbol, we can switch to Local-Exec, which links the
 792       // thread offset into the instruction.
 793       if (is_final)
 794         return tls::TLSOPT_TO_LE;
 795       return tls::TLSOPT_NONE;
 796
 797     case elfcpp::R_X86_64_TPOFF32:
 798       // When we already have Local-Exec, there is nothing further we
 799       // can do.
 800       return tls::TLSOPT_NONE;
 801
 802     default:
 803       gold_unreachable();
 804     }
 805 }
 806
 807 // Report an unsupported relocation against a local symbol.
 808
 809 void
 810 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 811                                              unsigned int r_type)
 812 {
 813   gold_error(_("%s: unsupported reloc %u against local symbol"),
 814              object->name().c_str(), r_type);
 815 }
 816
 817 // We are about to emit a dynamic relocation of type R_TYPE.  If the
 818 // dynamic linker does not support it, issue an error.  The GNU linker
 819 // only issues a non-PIC error for an allocated read-only section.
 820 // Here we know the section is allocated, but we don't know that it is
 821 // read-only.  But we check for all the relocation types which the
 822 // glibc dynamic linker supports, so it seems appropriate to issue an
 823 // error even if the section is not read-only.
 824
 825 void
 826 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
 827 {
 828   switch (r_type)
 829     {
 830       // These are the relocation types supported by glibc for x86_64.
 831     case elfcpp::R_X86_64_RELATIVE:
 832     case elfcpp::R_X86_64_GLOB_DAT:
 833     case elfcpp::R_X86_64_JUMP_SLOT:
 834     case elfcpp::R_X86_64_DTPMOD64:
 835     case elfcpp::R_X86_64_DTPOFF64:
 836     case elfcpp::R_X86_64_TPOFF64:
 837     case elfcpp::R_X86_64_64:
 838     case elfcpp::R_X86_64_32:
 839     case elfcpp::R_X86_64_PC32:
 840     case elfcpp::R_X86_64_COPY:
 841       return;
 842
 843     default:
 844       // This prevents us from issuing more than one error per reloc
 845       // section.  But we can still wind up issuing more than one
 846       // error per object file.
 847       if (this->issued_non_pic_error_)
 848         return;
 849       object->error(_("requires unsupported dynamic reloc; "
 850                       "recompile with -fPIC"));
 851       this->issued_non_pic_error_ = true;
 852       return;
 853
 854     case elfcpp::R_X86_64_NONE:
 855       gold_unreachable();
 856     }
 857 }
 858
 859 // Scan a relocation for a local symbol.
 860
 861 inline void
 862 Target_x86_64::Scan::local(const General_options&,
 863                            Symbol_table* symtab,
 864                            Layout* layout,
 865                            Target_x86_64* target,
 866                            Sized_relobj<64, false>* object,
 867                            unsigned int data_shndx,
 868                            Output_section* output_section,
 869                            const elfcpp::Rela<64, false>& reloc,
 870                            unsigned int r_type,
 871                            const elfcpp::Sym<64, false>& lsym)
 872 {
 873   switch (r_type)
 874     {
 875     case elfcpp::R_X86_64_NONE:
 876     case elfcpp::R_386_GNU_VTINHERIT:
 877     case elfcpp::R_386_GNU_VTENTRY:
 878       break;
 879
 880     case elfcpp::R_X86_64_64:
 881       // If building a shared library (or a position-independent
 882       // executable), we need to create a dynamic relocation for this
 883       // location.  The relocation applied at link time will apply the
 884       // link-time value, so we flag the location with an
 885       // R_X86_64_RELATIVE relocation so the dynamic loader can
 886       // relocate it easily.
 887       if (parameters->options().output_is_position_independent())
 888         {
 889           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 890           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 891           rela_dyn->add_local_relative(object, r_sym,
 892                                        elfcpp::R_X86_64_RELATIVE,
 893                                        output_section, data_shndx,
 894                                        reloc.get_r_offset(),
 895                                        reloc.get_r_addend());
 896         }
 897       break;
 898
 899     case elfcpp::R_X86_64_32:
 900     case elfcpp::R_X86_64_32S:
 901     case elfcpp::R_X86_64_16:
 902     case elfcpp::R_X86_64_8:
 903       // If building a shared library (or a position-independent
 904       // executable), we need to create a dynamic relocation for this
 905       // location.  We can't use an R_X86_64_RELATIVE relocation
 906       // because that is always a 64-bit relocation.
 907       if (parameters->options().output_is_position_independent())
 908         {
 909           this->check_non_pic(object, r_type);
 910
 911           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 912           if (lsym.get_st_type() != elfcpp::STT_SECTION)
 913             {
 914               unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 915               rela_dyn->add_local(object, r_sym, r_type, output_section,
 916                                   data_shndx, reloc.get_r_offset(),
 917                                   reloc.get_r_addend());
 918             }
 919           else
 920             {
 921               gold_assert(lsym.get_st_value() == 0);
 922               rela_dyn->add_local_section(object, lsym.get_st_shndx(),
 923                                           r_type, output_section,
 924                                           data_shndx, reloc.get_r_offset(),
 925                                           reloc.get_r_addend());
 926             }
 927         }
 928       break;
 929
 930     case elfcpp::R_X86_64_PC64:
 931     case elfcpp::R_X86_64_PC32:
 932     case elfcpp::R_X86_64_PC16:
 933     case elfcpp::R_X86_64_PC8:
 934       break;
 935
 936     case elfcpp::R_X86_64_PLT32:
 937       // Since we know this is a local symbol, we can handle this as a
 938       // PC32 reloc.
 939       break;
 940
 941     case elfcpp::R_X86_64_GOTPC32:
 942     case elfcpp::R_X86_64_GOTOFF64:
 943     case elfcpp::R_X86_64_GOTPC64:
 944     case elfcpp::R_X86_64_PLTOFF64:
 945       // We need a GOT section.
 946       target->got_section(symtab, layout);
 947       // For PLTOFF64, we'd normally want a PLT section, but since we
 948       // know this is a local symbol, no PLT is needed.
 949       break;
 950
 951     case elfcpp::R_X86_64_GOT64:
 952     case elfcpp::R_X86_64_GOT32:
 953     case elfcpp::R_X86_64_GOTPCREL64:
 954     case elfcpp::R_X86_64_GOTPCREL:
 955     case elfcpp::R_X86_64_GOTPLT64:
 956       {
 957         // The symbol requires a GOT entry.
 958         Output_data_got<64, false>* got = target->got_section(symtab, layout);
 959         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 960         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
 961           {
 962             // If we are generating a shared object, we need to add a
 963             // dynamic relocation for this symbol's GOT entry.
 964             if (parameters->options().output_is_position_independent())
 965               {
 966                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 967                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
 968                 if (r_type != elfcpp::R_X86_64_GOT32)
 969                   rela_dyn->add_local_relative(
 970                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
 971                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
 972                 else
 973                   {
 974                     this->check_non_pic(object, r_type);
 975
 976                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
 977                     rela_dyn->add_local(
 978                         object, r_sym, r_type, got,
 979                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
 980                   }
 981               }
 982           }
 983         // For GOTPLT64, we'd normally want a PLT section, but since
 984         // we know this is a local symbol, no PLT is needed.
 985       }
 986       break;
 987
 988     case elfcpp::R_X86_64_COPY:
 989     case elfcpp::R_X86_64_GLOB_DAT:
 990     case elfcpp::R_X86_64_JUMP_SLOT:
 991     case elfcpp::R_X86_64_RELATIVE:
 992       // These are outstanding tls relocs, which are unexpected when linking
 993     case elfcpp::R_X86_64_TPOFF64:
 994     case elfcpp::R_X86_64_DTPMOD64:
 995     case elfcpp::R_X86_64_TLSDESC:
 996       gold_error(_("%s: unexpected reloc %u in object file"),
 997                  object->name().c_str(), r_type);
 998       break;
 999
1000       // These are initial tls relocs, which are expected when linking
1001     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1002     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1003     case elfcpp::R_X86_64_TLSDESC_CALL:
1004     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1005     case elfcpp::R_X86_64_DTPOFF32:
1006     case elfcpp::R_X86_64_DTPOFF64:
1007     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1008     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1009       {
1010         bool output_is_shared = parameters->options().shared();
1011         const tls::Tls_optimization optimized_type
1012             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1013         switch (r_type)
1014           {
1015           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1016             if (optimized_type == tls::TLSOPT_NONE)
1017               {
1018                 // Create a pair of GOT entries for the module index and
1019                 // dtv-relative offset.
1020                 Output_data_got<64, false>* got
1021                     = target->got_section(symtab, layout);
1022                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1023                 got->add_local_pair_with_rela(object, r_sym,
1024                                               lsym.get_st_shndx(),
1025                                               GOT_TYPE_TLS_PAIR,
1026                                               target->rela_dyn_section(layout),
1027                                               elfcpp::R_X86_64_DTPMOD64, 0);
1028               }
1029             else if (optimized_type != tls::TLSOPT_TO_LE)
1030               unsupported_reloc_local(object, r_type);
1031             break;
1032
1033           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1034           case elfcpp::R_X86_64_TLSDESC_CALL:
1035             // FIXME: If not relaxing to LE, we need to generate
1036             // a GOT entry with a R_x86_64_TLSDESC reloc.
1037             if (optimized_type != tls::TLSOPT_TO_LE)
1038               unsupported_reloc_local(object, r_type);
1039             break;
1040
1041           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1042             if (optimized_type == tls::TLSOPT_NONE)
1043               {
1044                 // Create a GOT entry for the module index.
1045                 target->got_mod_index_entry(symtab, layout, object);
1046               }
1047             else if (optimized_type != tls::TLSOPT_TO_LE)
1048               unsupported_reloc_local(object, r_type);
1049             break;
1050
1051           case elfcpp::R_X86_64_DTPOFF32:
1052           case elfcpp::R_X86_64_DTPOFF64:
1053             break;
1054
1055           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1056             layout->set_has_static_tls();
1057             if (optimized_type == tls::TLSOPT_NONE)
1058               {
1059                 // Create a GOT entry for the tp-relative offset.
1060                 Output_data_got<64, false>* got
1061                     = target->got_section(symtab, layout);
1062                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1063                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1064                                          target->rela_dyn_section(layout),
1065                                          elfcpp::R_X86_64_TPOFF64);
1066               }
1067             else if (optimized_type != tls::TLSOPT_TO_LE)
1068               unsupported_reloc_local(object, r_type);
1069             break;
1070
1071           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1072             layout->set_has_static_tls();
1073             if (output_is_shared)
1074               unsupported_reloc_local(object, r_type);
1075             break;
1076
1077           default:
1078             gold_unreachable();
1079           }
1080       }
1081       break;
1082
1083     case elfcpp::R_X86_64_SIZE32:
1084     case elfcpp::R_X86_64_SIZE64:
1085     default:
1086       gold_error(_("%s: unsupported reloc %u against local symbol"),
1087                  object->name().c_str(), r_type);
1088       break;
1089     }
1090 }
1091
1092
1093 // Report an unsupported relocation against a global symbol.
1094
1095 void
1096 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1097                                               unsigned int r_type,
1098                                               Symbol* gsym)
1099 {
1100   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1101              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1102 }
1103
1104 // Scan a relocation for a global symbol.
1105
1106 inline void
1107 Target_x86_64::Scan::global(const General_options& options,
1108                             Symbol_table* symtab,
1109                             Layout* layout,
1110                             Target_x86_64* target,
1111                             Sized_relobj<64, false>* object,
1112                             unsigned int data_shndx,
1113                             Output_section* output_section,
1114                             const elfcpp::Rela<64, false>& reloc,
1115                             unsigned int r_type,
1116                             Symbol* gsym)
1117 {
1118   switch (r_type)
1119     {
1120     case elfcpp::R_X86_64_NONE:
1121     case elfcpp::R_386_GNU_VTINHERIT:
1122     case elfcpp::R_386_GNU_VTENTRY:
1123       break;
1124
1125     case elfcpp::R_X86_64_64:
1126     case elfcpp::R_X86_64_32:
1127     case elfcpp::R_X86_64_32S:
1128     case elfcpp::R_X86_64_16:
1129     case elfcpp::R_X86_64_8:
1130       {
1131         // Make a PLT entry if necessary.
1132         if (gsym->needs_plt_entry())
1133           {
1134             target->make_plt_entry(symtab, layout, gsym);
1135             // Since this is not a PC-relative relocation, we may be
1136             // taking the address of a function. In that case we need to
1137             // set the entry in the dynamic symbol table to the address of
1138             // the PLT entry.
1139             if (gsym->is_from_dynobj() && !parameters->options().shared())
1140               gsym->set_needs_dynsym_value();
1141           }
1142         // Make a dynamic relocation if necessary.
1143         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1144           {
1145             if (target->may_need_copy_reloc(gsym))
1146               {
1147                 target->copy_reloc(&options, symtab, layout, object,
1148                                    data_shndx, output_section, gsym, reloc);
1149               }
1150             else if (r_type == elfcpp::R_X86_64_64
1151                      && gsym->can_use_relative_reloc(false))
1152               {
1153                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1154                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1155                                               output_section, object,
1156                                               data_shndx, reloc.get_r_offset(),
1157                                               reloc.get_r_addend());
1158               }
1159             else
1160               {
1161                 this->check_non_pic(object, r_type);
1162                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1163                 rela_dyn->add_global(gsym, r_type, output_section, object,
1164                                      data_shndx, reloc.get_r_offset(),
1165                                      reloc.get_r_addend());
1166               }
1167           }
1168       }
1169       break;
1170
1171     case elfcpp::R_X86_64_PC64:
1172     case elfcpp::R_X86_64_PC32:
1173     case elfcpp::R_X86_64_PC16:
1174     case elfcpp::R_X86_64_PC8:
1175       {
1176         // Make a PLT entry if necessary.
1177         if (gsym->needs_plt_entry())
1178           target->make_plt_entry(symtab, layout, gsym);
1179         // Make a dynamic relocation if necessary.
1180         int flags = Symbol::NON_PIC_REF;
1181         if (gsym->type() == elfcpp::STT_FUNC)
1182           flags |= Symbol::FUNCTION_CALL;
1183         if (gsym->needs_dynamic_reloc(flags))
1184           {
1185             if (target->may_need_copy_reloc(gsym))
1186               {
1187                 target->copy_reloc(&options, symtab, layout, object,
1188                                    data_shndx, output_section, gsym, reloc);
1189               }
1190             else
1191               {
1192                 this->check_non_pic(object, r_type);
1193                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1194                 rela_dyn->add_global(gsym, r_type, output_section, object,
1195                                      data_shndx, reloc.get_r_offset(),
1196                                      reloc.get_r_addend());
1197               }
1198           }
1199       }
1200       break;
1201
1202     case elfcpp::R_X86_64_GOT64:
1203     case elfcpp::R_X86_64_GOT32:
1204     case elfcpp::R_X86_64_GOTPCREL64:
1205     case elfcpp::R_X86_64_GOTPCREL:
1206     case elfcpp::R_X86_64_GOTPLT64:
1207       {
1208         // The symbol requires a GOT entry.
1209         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1210         if (gsym->final_value_is_known())
1211           got->add_global(gsym, GOT_TYPE_STANDARD);
1212         else
1213           {
1214             // If this symbol is not fully resolved, we need to add a
1215             // dynamic relocation for it.
1216             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1217             if (gsym->is_from_dynobj()
1218                 || gsym->is_undefined()
1219                 || gsym->is_preemptible())
1220               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1221                                         elfcpp::R_X86_64_GLOB_DAT);
1222             else
1223               {
1224                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1225                   rela_dyn->add_global_relative(
1226                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1227                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1228               }
1229           }
1230         // For GOTPLT64, we also need a PLT entry (but only if the
1231         // symbol is not fully resolved).
1232         if (r_type == elfcpp::R_X86_64_GOTPLT64
1233             && !gsym->final_value_is_known())
1234           target->make_plt_entry(symtab, layout, gsym);
1235       }
1236       break;
1237
1238     case elfcpp::R_X86_64_PLT32:
1239       // If the symbol is fully resolved, this is just a PC32 reloc.
1240       // Otherwise we need a PLT entry.
1241       if (gsym->final_value_is_known())
1242         break;
1243       // If building a shared library, we can also skip the PLT entry
1244       // if the symbol is defined in the output file and is protected
1245       // or hidden.
1246       if (gsym->is_defined()
1247           && !gsym->is_from_dynobj()
1248           && !gsym->is_preemptible())
1249         break;
1250       target->make_plt_entry(symtab, layout, gsym);
1251       break;
1252
1253     case elfcpp::R_X86_64_GOTPC32:
1254     case elfcpp::R_X86_64_GOTOFF64:
1255     case elfcpp::R_X86_64_GOTPC64:
1256     case elfcpp::R_X86_64_PLTOFF64:
1257       // We need a GOT section.
1258       target->got_section(symtab, layout);
1259       // For PLTOFF64, we also need a PLT entry (but only if the
1260       // symbol is not fully resolved).
1261       if (r_type == elfcpp::R_X86_64_PLTOFF64
1262           && !gsym->final_value_is_known())
1263         target->make_plt_entry(symtab, layout, gsym);
1264       break;
1265
1266     case elfcpp::R_X86_64_COPY:
1267     case elfcpp::R_X86_64_GLOB_DAT:
1268     case elfcpp::R_X86_64_JUMP_SLOT:
1269     case elfcpp::R_X86_64_RELATIVE:
1270       // These are outstanding tls relocs, which are unexpected when linking
1271     case elfcpp::R_X86_64_TPOFF64:
1272     case elfcpp::R_X86_64_DTPMOD64:
1273     case elfcpp::R_X86_64_TLSDESC:
1274       gold_error(_("%s: unexpected reloc %u in object file"),
1275                  object->name().c_str(), r_type);
1276       break;
1277
1278       // These are initial tls relocs, which are expected for global()
1279     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1280     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1281     case elfcpp::R_X86_64_TLSDESC_CALL:
1282     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1283     case elfcpp::R_X86_64_DTPOFF32:
1284     case elfcpp::R_X86_64_DTPOFF64:
1285     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1286     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1287       {
1288         const bool is_final = gsym->final_value_is_known();
1289         const tls::Tls_optimization optimized_type
1290             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1291         switch (r_type)
1292           {
1293           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1294             if (optimized_type == tls::TLSOPT_NONE)
1295               {
1296                 // Create a pair of GOT entries for the module index and
1297                 // dtv-relative offset.
1298                 Output_data_got<64, false>* got
1299                     = target->got_section(symtab, layout);
1300                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1301                                                target->rela_dyn_section(layout),
1302                                                elfcpp::R_X86_64_DTPMOD64,
1303                                                elfcpp::R_X86_64_DTPOFF64);
1304               }
1305             else if (optimized_type == tls::TLSOPT_TO_IE)
1306               {
1307                 // Create a GOT entry for the tp-relative offset.
1308                 Output_data_got<64, false>* got
1309                     = target->got_section(symtab, layout);
1310                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1311                                           target->rela_dyn_section(layout),
1312                                           elfcpp::R_X86_64_TPOFF64);
1313               }
1314             else if (optimized_type != tls::TLSOPT_TO_LE)
1315               unsupported_reloc_global(object, r_type, gsym);
1316             break;
1317
1318           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1319           case elfcpp::R_X86_64_TLSDESC_CALL:
1320             // FIXME: If not relaxing to LE, we need to generate
1321             // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1322             if (optimized_type != tls::TLSOPT_TO_LE)
1323               unsupported_reloc_global(object, r_type, gsym);
1324             break;
1325
1326           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1327             if (optimized_type == tls::TLSOPT_NONE)
1328               {
1329                 // Create a GOT entry for the module index.
1330                 target->got_mod_index_entry(symtab, layout, object);
1331               }
1332             else if (optimized_type != tls::TLSOPT_TO_LE)
1333               unsupported_reloc_global(object, r_type, gsym);
1334             break;
1335
1336           case elfcpp::R_X86_64_DTPOFF32:
1337           case elfcpp::R_X86_64_DTPOFF64:
1338             break;
1339
1340           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1341             layout->set_has_static_tls();
1342             if (optimized_type == tls::TLSOPT_NONE)
1343               {
1344                 // Create a GOT entry for the tp-relative offset.
1345                 Output_data_got<64, false>* got
1346                     = target->got_section(symtab, layout);
1347                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1348                                           target->rela_dyn_section(layout),
1349                                           elfcpp::R_X86_64_TPOFF64);
1350               }
1351             else if (optimized_type != tls::TLSOPT_TO_LE)
1352               unsupported_reloc_global(object, r_type, gsym);
1353             break;
1354
1355           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1356             layout->set_has_static_tls();
1357             if (parameters->options().shared())
1358               unsupported_reloc_local(object, r_type);
1359             break;
1360
1361           default:
1362             gold_unreachable();
1363           }
1364       }
1365       break;
1366
1367     case elfcpp::R_X86_64_SIZE32:
1368     case elfcpp::R_X86_64_SIZE64:
1369     default:
1370       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1371                  object->name().c_str(), r_type,
1372                  gsym->demangled_name().c_str());
1373       break;
1374     }
1375 }
1376
1377 // Scan relocations for a section.
1378
1379 void
1380 Target_x86_64::scan_relocs(const General_options& options,
1381                            Symbol_table* symtab,
1382                            Layout* layout,
1383                            Sized_relobj<64, false>* object,
1384                            unsigned int data_shndx,
1385                            unsigned int sh_type,
1386                            const unsigned char* prelocs,
1387                            size_t reloc_count,
1388                            Output_section* output_section,
1389                            bool needs_special_offset_handling,
1390                            size_t local_symbol_count,
1391                            const unsigned char* plocal_symbols)
1392 {
1393   if (sh_type == elfcpp::SHT_REL)
1394     {
1395       gold_error(_("%s: unsupported REL reloc section"),
1396                  object->name().c_str());
1397       return;
1398     }
1399
1400   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1401       Target_x86_64::Scan>(
1402     options,
1403     symtab,
1404     layout,
1405     this,
1406     object,
1407     data_shndx,
1408     prelocs,
1409     reloc_count,
1410     output_section,
1411     needs_special_offset_handling,
1412     local_symbol_count,
1413     plocal_symbols);
1414 }
1415
1416 // Finalize the sections.
1417
1418 void
1419 Target_x86_64::do_finalize_sections(Layout* layout)
1420 {
1421   // Fill in some more dynamic tags.
1422   Output_data_dynamic* const odyn = layout->dynamic_data();
1423   if (odyn != NULL)
1424     {
1425       if (this->got_plt_ != NULL)
1426         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1427
1428       if (this->plt_ != NULL)
1429         {
1430           const Output_data* od = this->plt_->rel_plt();
1431           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1432           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1433           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1434         }
1435
1436       if (this->rela_dyn_ != NULL)
1437         {
1438           const Output_data* od = this->rela_dyn_;
1439           odyn->add_section_address(elfcpp::DT_RELA, od);
1440           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1441           odyn->add_constant(elfcpp::DT_RELAENT,
1442                              elfcpp::Elf_sizes<64>::rela_size);
1443         }
1444
1445       if (!parameters->options().shared())
1446         {
1447           // The value of the DT_DEBUG tag is filled in by the dynamic
1448           // linker at run time, and used by the debugger.
1449           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1450         }
1451     }
1452
1453   // Emit any relocs we saved in an attempt to avoid generating COPY
1454   // relocs.
1455   if (this->copy_relocs_ == NULL)
1456     return;
1457   if (this->copy_relocs_->any_to_emit())
1458     {
1459       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1460       this->copy_relocs_->emit(rela_dyn);
1461     }
1462   delete this->copy_relocs_;
1463   this->copy_relocs_ = NULL;
1464 }
1465
1466 // Perform a relocation.
1467
1468 inline bool
1469 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1470                                   Target_x86_64* target,
1471                                   size_t relnum,
1472                                   const elfcpp::Rela<64, false>& rela,
1473                                   unsigned int r_type,
1474                                   const Sized_symbol<64>* gsym,
1475                                   const Symbol_value<64>* psymval,
1476                                   unsigned char* view,
1477                                   elfcpp::Elf_types<64>::Elf_Addr address,
1478                                   section_size_type view_size)
1479 {
1480   if (this->skip_call_tls_get_addr_)
1481     {
1482       if (r_type != elfcpp::R_X86_64_PLT32
1483           || gsym == NULL
1484           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1485         {
1486           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1487                                  _("missing expected TLS relocation"));
1488         }
1489       else
1490         {
1491           this->skip_call_tls_get_addr_ = false;
1492           return false;
1493         }
1494     }
1495
1496   // Pick the value to use for symbols defined in shared objects.
1497   Symbol_value<64> symval;
1498   if (gsym != NULL
1499       && (gsym->is_from_dynobj()
1500           || (parameters->options().shared()
1501               && (gsym->is_undefined() || gsym->is_preemptible())))
1502       && gsym->has_plt_offset())
1503     {
1504       symval.set_output_value(target->plt_section()->address()
1505                               + gsym->plt_offset());
1506       psymval = &symval;
1507     }
1508
1509   const Sized_relobj<64, false>* object = relinfo->object;
1510   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1511
1512   // Get the GOT offset if needed.
1513   // The GOT pointer points to the end of the GOT section.
1514   // We need to subtract the size of the GOT section to get
1515   // the actual offset to use in the relocation.
1516   bool have_got_offset = false;
1517   unsigned int got_offset = 0;
1518   switch (r_type)
1519     {
1520     case elfcpp::R_X86_64_GOT32:
1521     case elfcpp::R_X86_64_GOT64:
1522     case elfcpp::R_X86_64_GOTPLT64:
1523     case elfcpp::R_X86_64_GOTPCREL:
1524     case elfcpp::R_X86_64_GOTPCREL64:
1525       if (gsym != NULL)
1526         {
1527           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1528           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1529         }
1530       else
1531         {
1532           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1533           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1534           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1535                         - target->got_size());
1536         }
1537       have_got_offset = true;
1538       break;
1539
1540     default:
1541       break;
1542     }
1543
1544   switch (r_type)
1545     {
1546     case elfcpp::R_X86_64_NONE:
1547     case elfcpp::R_386_GNU_VTINHERIT:
1548     case elfcpp::R_386_GNU_VTENTRY:
1549       break;
1550
1551     case elfcpp::R_X86_64_64:
1552       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1553       break;
1554
1555     case elfcpp::R_X86_64_PC64:
1556       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1557                                               address);
1558       break;
1559
1560     case elfcpp::R_X86_64_32:
1561       // FIXME: we need to verify that value + addend fits into 32 bits:
1562       //    uint64_t x = value + addend;
1563       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1564       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1565       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1566       break;
1567
1568     case elfcpp::R_X86_64_32S:
1569       // FIXME: we need to verify that value + addend fits into 32 bits:
1570       //    int64_t x = value + addend;   // note this quantity is signed!
1571       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1572       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1573       break;
1574
1575     case elfcpp::R_X86_64_PC32:
1576       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1577                                               address);
1578       break;
1579
1580     case elfcpp::R_X86_64_16:
1581       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1582       break;
1583
1584     case elfcpp::R_X86_64_PC16:
1585       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1586                                               address);
1587       break;
1588
1589     case elfcpp::R_X86_64_8:
1590       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1591       break;
1592
1593     case elfcpp::R_X86_64_PC8:
1594       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1595                                              address);
1596       break;
1597
1598     case elfcpp::R_X86_64_PLT32:
1599       gold_assert(gsym == NULL
1600                   || gsym->has_plt_offset()
1601                   || gsym->final_value_is_known()
1602                   || (gsym->is_defined()
1603                       && !gsym->is_from_dynobj()
1604                       && !gsym->is_preemptible()));
1605       // Note: while this code looks the same as for R_X86_64_PC32, it
1606       // behaves differently because psymval was set to point to
1607       // the PLT entry, rather than the symbol, in Scan::global().
1608       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1609                                               address);
1610       break;
1611
1612     case elfcpp::R_X86_64_PLTOFF64:
1613       {
1614         gold_assert(gsym);
1615         gold_assert(gsym->has_plt_offset()
1616                     || gsym->final_value_is_known());
1617         elfcpp::Elf_types<64>::Elf_Addr got_address;
1618         got_address = target->got_section(NULL, NULL)->address();
1619         Relocate_functions<64, false>::rela64(view, object, psymval,
1620                                               addend - got_address);
1621       }
1622
1623     case elfcpp::R_X86_64_GOT32:
1624       gold_assert(have_got_offset);
1625       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1626       break;
1627
1628     case elfcpp::R_X86_64_GOTPC32:
1629       {
1630         gold_assert(gsym);
1631         elfcpp::Elf_types<64>::Elf_Addr value;
1632         value = target->got_plt_section()->address();
1633         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1634       }
1635       break;
1636
1637     case elfcpp::R_X86_64_GOT64:
1638       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1639       // Since we always add a PLT entry, this is equivalent.
1640     case elfcpp::R_X86_64_GOTPLT64:
1641       gold_assert(have_got_offset);
1642       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1643       break;
1644
1645     case elfcpp::R_X86_64_GOTPC64:
1646       {
1647         gold_assert(gsym);
1648         elfcpp::Elf_types<64>::Elf_Addr value;
1649         value = target->got_plt_section()->address();
1650         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1651       }
1652       break;
1653
1654     case elfcpp::R_X86_64_GOTOFF64:
1655       {
1656         elfcpp::Elf_types<64>::Elf_Addr value;
1657         value = (psymval->value(object, 0)
1658                  - target->got_plt_section()->address());
1659         Relocate_functions<64, false>::rela64(view, value, addend);
1660       }
1661       break;
1662
1663     case elfcpp::R_X86_64_GOTPCREL:
1664       {
1665         gold_assert(have_got_offset);
1666         elfcpp::Elf_types<64>::Elf_Addr value;
1667         value = target->got_plt_section()->address() + got_offset;
1668         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1669       }
1670       break;
1671
1672     case elfcpp::R_X86_64_GOTPCREL64:
1673       {
1674         gold_assert(have_got_offset);
1675         elfcpp::Elf_types<64>::Elf_Addr value;
1676         value = target->got_plt_section()->address() + got_offset;
1677         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1678       }
1679       break;
1680
1681     case elfcpp::R_X86_64_COPY:
1682     case elfcpp::R_X86_64_GLOB_DAT:
1683     case elfcpp::R_X86_64_JUMP_SLOT:
1684     case elfcpp::R_X86_64_RELATIVE:
1685       // These are outstanding tls relocs, which are unexpected when linking
1686     case elfcpp::R_X86_64_TPOFF64:
1687     case elfcpp::R_X86_64_DTPMOD64:
1688     case elfcpp::R_X86_64_TLSDESC:
1689       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1690                              _("unexpected reloc %u in object file"),
1691                              r_type);
1692       break;
1693
1694       // These are initial tls relocs, which are expected when linking
1695     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1696     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1697     case elfcpp::R_X86_64_TLSDESC_CALL:
1698     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1699     case elfcpp::R_X86_64_DTPOFF32:
1700     case elfcpp::R_X86_64_DTPOFF64:
1701     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1702     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1703       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1704                          view, address, view_size);
1705       break;
1706
1707     case elfcpp::R_X86_64_SIZE32:
1708     case elfcpp::R_X86_64_SIZE64:
1709     default:
1710       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1711                              _("unsupported reloc %u"),
1712                              r_type);
1713       break;
1714     }
1715
1716   return true;
1717 }
1718
1719 // Perform a TLS relocation.
1720
1721 inline void
1722 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1723                                       Target_x86_64* target,
1724                                       size_t relnum,
1725                                       const elfcpp::Rela<64, false>& rela,
1726                                       unsigned int r_type,
1727                                       const Sized_symbol<64>* gsym,
1728                                       const Symbol_value<64>* psymval,
1729                                       unsigned char* view,
1730                                       elfcpp::Elf_types<64>::Elf_Addr address,
1731                                       section_size_type view_size)
1732 {
1733   Output_segment* tls_segment = relinfo->layout->tls_segment();
1734
1735   const Sized_relobj<64, false>* object = relinfo->object;
1736   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1737
1738   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1739
1740   const bool is_final = (gsym == NULL
1741                          ? !parameters->options().output_is_position_independent()
1742                          : gsym->final_value_is_known());
1743   const tls::Tls_optimization optimized_type
1744       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1745   switch (r_type)
1746     {
1747     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1748     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1749     case elfcpp::R_X86_64_TLSDESC_CALL:
1750       if (optimized_type == tls::TLSOPT_TO_LE)
1751         {
1752           gold_assert(tls_segment != NULL);
1753           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1754                              rela, r_type, value, view,
1755                              view_size);
1756           break;
1757         }
1758       else
1759         {
1760           unsigned int got_offset;
1761           if (gsym != NULL)
1762             {
1763               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_PAIR));
1764               got_offset = (gsym->got_offset(GOT_TYPE_TLS_PAIR)
1765                             - target->got_size());
1766             }
1767           else
1768             {
1769               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1770               gold_assert(object->local_has_got_offset(r_sym,
1771                           GOT_TYPE_TLS_PAIR));
1772               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_PAIR)
1773                             - target->got_size());
1774             }
1775           if (optimized_type == tls::TLSOPT_TO_IE)
1776             {
1777               gold_assert(tls_segment != NULL);
1778               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
1779                                  got_offset, view, view_size);
1780               break;
1781             }
1782           else if (optimized_type == tls::TLSOPT_NONE)
1783             {
1784               // Relocate the field with the offset of the pair of GOT
1785               // entries.
1786               value = target->got_plt_section()->address() + got_offset;
1787               Relocate_functions<64, false>::pcrela32(view, value, addend,
1788                                                       address);
1789               break;
1790             }
1791         }
1792       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1793                              _("unsupported reloc %u"), r_type);
1794       break;
1795
1796     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1797       if (optimized_type == tls::TLSOPT_TO_LE)
1798         {
1799           gold_assert(tls_segment != NULL);
1800           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
1801                              value, view, view_size);
1802           break;
1803         }
1804       else if (optimized_type == tls::TLSOPT_NONE)
1805         {
1806           // Relocate the field with the offset of the GOT entry for
1807           // the module index.
1808           unsigned int got_offset;
1809           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
1810                         - target->got_size());
1811           value = target->got_plt_section()->address() + got_offset;
1812           Relocate_functions<64, false>::pcrela32(view, value, addend,
1813                                                   address);
1814           break;
1815         }
1816       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1817                              _("unsupported reloc %u"), r_type);
1818       break;
1819
1820     case elfcpp::R_X86_64_DTPOFF32:
1821       gold_assert(tls_segment != NULL);
1822       if (optimized_type == tls::TLSOPT_TO_LE)
1823         value -= tls_segment->memsz();
1824       Relocate_functions<64, false>::rela32(view, value, 0);
1825       break;
1826
1827     case elfcpp::R_X86_64_DTPOFF64:
1828       gold_assert(tls_segment != NULL);
1829       if (optimized_type == tls::TLSOPT_TO_LE)
1830         value -= tls_segment->memsz();
1831       Relocate_functions<64, false>::rela64(view, value, 0);
1832       break;
1833
1834     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1835       if (optimized_type == tls::TLSOPT_TO_LE)
1836         {
1837           gold_assert(tls_segment != NULL);
1838           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1839                                                 rela, r_type, value, view,
1840                                                 view_size);
1841           break;
1842         }
1843       else if (optimized_type == tls::TLSOPT_NONE)
1844         {
1845           // Relocate the field with the offset of the GOT entry for
1846           // the tp-relative offset of the symbol.
1847           unsigned int got_offset;
1848           if (gsym != NULL)
1849             {
1850               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
1851               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
1852                             - target->got_size());
1853             }
1854           else
1855             {
1856               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1857               gold_assert(object->local_has_got_offset(r_sym,
1858                                                        GOT_TYPE_TLS_OFFSET));
1859               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
1860                             - target->got_size());
1861             }
1862           value = target->got_plt_section()->address() + got_offset;
1863           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1864           break;
1865         }
1866       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1867                              _("unsupported reloc type %u"),
1868                              r_type);
1869       break;
1870
1871     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1872       value -= tls_segment->memsz();
1873       Relocate_functions<64, false>::rela32(view, value, 0);
1874       break;
1875     }
1876 }
1877
1878 // Do a relocation in which we convert a TLS General-Dynamic to an
1879 // Initial-Exec.
1880
1881 inline void
1882 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
1883                                       size_t relnum,
1884                                       Output_segment* tls_segment,
1885                                       const elfcpp::Rela<64, false>& rela,
1886                                       unsigned int,
1887                                       elfcpp::Elf_types<64>::Elf_Addr value,
1888                                       unsigned char* view,
1889                                       section_size_type view_size)
1890 {
1891   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1892   // .word 0x6666; rex64; call __tls_get_addr
1893   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
1894
1895   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1896   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1897
1898   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1899                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1900   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1901                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1902
1903   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
1904
1905   value -= tls_segment->memsz();
1906   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1907
1908   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1909   // We can skip it.
1910   this->skip_call_tls_get_addr_ = true;
1911 }
1912
1913 // Do a relocation in which we convert a TLS General-Dynamic to a
1914 // Local-Exec.
1915
1916 inline void
1917 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
1918                                       size_t relnum,
1919                                       Output_segment* tls_segment,
1920                                       const elfcpp::Rela<64, false>& rela,
1921                                       unsigned int,
1922                                       elfcpp::Elf_types<64>::Elf_Addr value,
1923                                       unsigned char* view,
1924                                       section_size_type view_size)
1925 {
1926   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1927   // .word 0x6666; rex64; call __tls_get_addr
1928   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1929
1930   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1931   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1932
1933   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1934                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1935   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1936                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1937
1938   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1939
1940   value -= tls_segment->memsz();
1941   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1942
1943   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1944   // We can skip it.
1945   this->skip_call_tls_get_addr_ = true;
1946 }
1947
1948 inline void
1949 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
1950                                       size_t relnum,
1951                                       Output_segment*,
1952                                       const elfcpp::Rela<64, false>& rela,
1953                                       unsigned int,
1954                                       elfcpp::Elf_types<64>::Elf_Addr,
1955                                       unsigned char* view,
1956                                       section_size_type view_size)
1957 {
1958   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1959   // ... leq foo@dtpoff(%rax),%reg
1960   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1961
1962   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1963   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
1964
1965   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1966                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
1967
1968   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
1969
1970   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1971
1972   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1973   // We can skip it.
1974   this->skip_call_tls_get_addr_ = true;
1975 }
1976
1977 // Do a relocation in which we convert a TLS Initial-Exec to a
1978 // Local-Exec.
1979
1980 inline void
1981 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
1982                                       size_t relnum,
1983                                       Output_segment* tls_segment,
1984                                       const elfcpp::Rela<64, false>& rela,
1985                                       unsigned int,
1986                                       elfcpp::Elf_types<64>::Elf_Addr value,
1987                                       unsigned char* view,
1988                                       section_size_type view_size)
1989 {
1990   // We need to examine the opcodes to figure out which instruction we
1991   // are looking at.
1992
1993   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
1994   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
1995
1996   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1997   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
1998
1999   unsigned char op1 = view[-3];
2000   unsigned char op2 = view[-2];
2001   unsigned char op3 = view[-1];
2002   unsigned char reg = op3 >> 3;
2003
2004   if (op2 == 0x8b)
2005     {
2006       // movq
2007       if (op1 == 0x4c)
2008         view[-3] = 0x49;
2009       view[-2] = 0xc7;
2010       view[-1] = 0xc0 | reg;
2011     }
2012   else if (reg == 4)
2013     {
2014       // Special handling for %rsp.
2015       if (op1 == 0x4c)
2016         view[-3] = 0x49;
2017       view[-2] = 0x81;
2018       view[-1] = 0xc0 | reg;
2019     }
2020   else
2021     {
2022       // addq
2023       if (op1 == 0x4c)
2024         view[-3] = 0x4d;
2025       view[-2] = 0x8d;
2026       view[-1] = 0x80 | reg | (reg << 3);
2027     }
2028
2029   value -= tls_segment->memsz();
2030   Relocate_functions<64, false>::rela32(view, value, 0);
2031 }
2032
2033 // Relocate section data.
2034
2035 void
2036 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
2037                                 unsigned int sh_type,
2038                                 const unsigned char* prelocs,
2039                                 size_t reloc_count,
2040                                 Output_section* output_section,
2041                                 bool needs_special_offset_handling,
2042                                 unsigned char* view,
2043                                 elfcpp::Elf_types<64>::Elf_Addr address,
2044                                 section_size_type view_size)
2045 {
2046   gold_assert(sh_type == elfcpp::SHT_RELA);
2047
2048   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2049                          Target_x86_64::Relocate>(
2050     relinfo,
2051     this,
2052     prelocs,
2053     reloc_count,
2054     output_section,
2055     needs_special_offset_handling,
2056     view,
2057     address,
2058     view_size);
2059 }
2060
2061 // Return the size of a relocation while scanning during a relocatable
2062 // link.
2063
2064 unsigned int
2065 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2066     unsigned int r_type,
2067     Relobj* object)
2068 {
2069   switch (r_type)
2070     {
2071     case elfcpp::R_X86_64_NONE:
2072     case elfcpp::R_386_GNU_VTINHERIT:
2073     case elfcpp::R_386_GNU_VTENTRY:
2074     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2075     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2076     case elfcpp::R_X86_64_TLSDESC_CALL:
2077     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2078     case elfcpp::R_X86_64_DTPOFF32:
2079     case elfcpp::R_X86_64_DTPOFF64:
2080     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2081     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2082       return 0;
2083
2084     case elfcpp::R_X86_64_64:
2085     case elfcpp::R_X86_64_PC64:
2086     case elfcpp::R_X86_64_GOTOFF64:
2087     case elfcpp::R_X86_64_GOTPC64:
2088     case elfcpp::R_X86_64_PLTOFF64:
2089     case elfcpp::R_X86_64_GOT64:
2090     case elfcpp::R_X86_64_GOTPCREL64:
2091     case elfcpp::R_X86_64_GOTPCREL:
2092     case elfcpp::R_X86_64_GOTPLT64:
2093       return 8;
2094
2095     case elfcpp::R_X86_64_32:
2096     case elfcpp::R_X86_64_32S:
2097     case elfcpp::R_X86_64_PC32:
2098     case elfcpp::R_X86_64_PLT32:
2099     case elfcpp::R_X86_64_GOTPC32:
2100     case elfcpp::R_X86_64_GOT32:
2101       return 4;
2102
2103     case elfcpp::R_X86_64_16:
2104     case elfcpp::R_X86_64_PC16:
2105       return 2;
2106
2107     case elfcpp::R_X86_64_8:
2108     case elfcpp::R_X86_64_PC8:
2109       return 1;
2110
2111     case elfcpp::R_X86_64_COPY:
2112     case elfcpp::R_X86_64_GLOB_DAT:
2113     case elfcpp::R_X86_64_JUMP_SLOT:
2114     case elfcpp::R_X86_64_RELATIVE:
2115       // These are outstanding tls relocs, which are unexpected when linking
2116     case elfcpp::R_X86_64_TPOFF64:
2117     case elfcpp::R_X86_64_DTPMOD64:
2118     case elfcpp::R_X86_64_TLSDESC:
2119       object->error(_("unexpected reloc %u in object file"), r_type);
2120       return 0;
2121
2122     case elfcpp::R_X86_64_SIZE32:
2123     case elfcpp::R_X86_64_SIZE64:
2124     default:
2125       object->error(_("unsupported reloc %u against local symbol"), r_type);
2126       return 0;
2127     }
2128 }
2129
2130 // Scan the relocs during a relocatable link.
2131
2132 void
2133 Target_x86_64::scan_relocatable_relocs(const General_options& options,
2134                                        Symbol_table* symtab,
2135                                        Layout* layout,
2136                                        Sized_relobj<64, false>* object,
2137                                        unsigned int data_shndx,
2138                                        unsigned int sh_type,
2139                                        const unsigned char* prelocs,
2140                                        size_t reloc_count,
2141                                        Output_section* output_section,
2142                                        bool needs_special_offset_handling,
2143                                        size_t local_symbol_count,
2144                                        const unsigned char* plocal_symbols,
2145                                        Relocatable_relocs* rr)
2146 {
2147   gold_assert(sh_type == elfcpp::SHT_RELA);
2148
2149   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2150     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2151
2152   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2153       Scan_relocatable_relocs>(
2154     options,
2155     symtab,
2156     layout,
2157     object,
2158     data_shndx,
2159     prelocs,
2160     reloc_count,
2161     output_section,
2162     needs_special_offset_handling,
2163     local_symbol_count,
2164     plocal_symbols,
2165     rr);
2166 }
2167
2168 // Relocate a section during a relocatable link.
2169
2170 void
2171 Target_x86_64::relocate_for_relocatable(
2172     const Relocate_info<64, false>* relinfo,
2173     unsigned int sh_type,
2174     const unsigned char* prelocs,
2175     size_t reloc_count,
2176     Output_section* output_section,
2177     off_t offset_in_output_section,
2178     const Relocatable_relocs* rr,
2179     unsigned char* view,
2180     elfcpp::Elf_types<64>::Elf_Addr view_address,
2181     section_size_type view_size,
2182     unsigned char* reloc_view,
2183     section_size_type reloc_view_size)
2184 {
2185   gold_assert(sh_type == elfcpp::SHT_RELA);
2186
2187   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2188     relinfo,
2189     prelocs,
2190     reloc_count,
2191     output_section,
2192     offset_in_output_section,
2193     rr,
2194     view,
2195     view_address,
2196     view_size,
2197     reloc_view,
2198     reloc_view_size);
2199 }
2200
2201 // Return the value to use for a dynamic which requires special
2202 // treatment.  This is how we support equality comparisons of function
2203 // pointers across shared library boundaries, as described in the
2204 // processor specific ABI supplement.
2205
2206 uint64_t
2207 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2208 {
2209   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2210   return this->plt_section()->address() + gsym->plt_offset();
2211 }
2212
2213 // Return a string used to fill a code section with nops to take up
2214 // the specified length.
2215
2216 std::string
2217 Target_x86_64::do_code_fill(section_size_type length) const
2218 {
2219   if (length >= 16)
2220     {
2221       // Build a jmpq instruction to skip over the bytes.
2222       unsigned char jmp[5];
2223       jmp[0] = 0xe9;
2224       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2225       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2226               + std::string(length - 5, '\0'));
2227     }
2228
2229   // Nop sequences of various lengths.
2230   const char nop1[1] = { 0x90 };                   // nop
2231   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2232   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2233   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2234   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2235                          0x00 };                   // leal 0(%esi,1),%esi
2236   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2237                          0x00, 0x00 };
2238   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2239                          0x00, 0x00, 0x00 };
2240   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2241                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2242   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2243                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2244                          0x00 };
2245   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2246                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2247                            0x00, 0x00 };
2248   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2249                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2250                            0x00, 0x00, 0x00 };
2251   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2252                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2253                            0x00, 0x00, 0x00, 0x00 };
2254   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2255                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2256                            0x27, 0x00, 0x00, 0x00,
2257                            0x00 };
2258   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2259                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2260                            0xbc, 0x27, 0x00, 0x00,
2261                            0x00, 0x00 };
2262   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2263                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2264                            0x90, 0x90, 0x90, 0x90,
2265                            0x90, 0x90, 0x90 };
2266
2267   const char* nops[16] = {
2268     NULL,
2269     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2270     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2271   };
2272
2273   return std::string(nops[length], length);
2274 }
2275
2276 // The selector for x86_64 object files.
2277
2278 class Target_selector_x86_64 : public Target_selector
2279 {
2280 public:
2281   Target_selector_x86_64()
2282     : Target_selector(elfcpp::EM_X86_64, 64, false, "elf64-x86-64")
2283   { }
2284
2285   Target*
2286   do_instantiate_target()
2287   { return new Target_x86_64(); }
2288 };
2289
2290 Target_selector_x86_64 target_selector_x86_64;
2291
2292 } // End anonymous namespace.