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 "copy-relocs.h"
  36 #include "target.h"
  37 #include "target-reloc.h"
  38 #include "target-select.h"
  39 #include "tls.h"
  40
  41 namespace
  42 {
  43
  44 using namespace gold;
  45
  46 class Output_data_plt_x86_64;
  47
  48 // The x86_64 target class.
  49 // See the ABI at
  50 //   http://www.x86-64.org/documentation/abi.pdf
  51 // TLS info comes from
  52 //   http://people.redhat.com/drepper/tls.pdf
  53 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  54
  55 class Target_x86_64 : public Sized_target<64, false>
  56 {
  57  public:
  58   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
  59   // uses only Elf64_Rela relocation entries with explicit addends."
  60   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  61
  62   Target_x86_64()
  63     : Sized_target<64, false>(&x86_64_info),
  64       got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
  65       copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
  66       got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
  67   { }
  68
  69   // Scan the relocations to look for symbol adjustments.
  70   void
  71   scan_relocs(const General_options& options,
  72               Symbol_table* symtab,
  73               Layout* layout,
  74               Sized_relobj<64, false>* object,
  75               unsigned int data_shndx,
  76               unsigned int sh_type,
  77               const unsigned char* prelocs,
  78               size_t reloc_count,
  79               Output_section* output_section,
  80               bool needs_special_offset_handling,
  81               size_t local_symbol_count,
  82               const unsigned char* plocal_symbols);
  83
  84   // Finalize the sections.
  85   void
  86   do_finalize_sections(Layout*);
  87
  88   // Return the value to use for a dynamic which requires special
  89   // treatment.
  90   uint64_t
  91   do_dynsym_value(const Symbol*) const;
  92
  93   // Relocate a section.
  94   void
  95   relocate_section(const Relocate_info<64, false>*,
  96                    unsigned int sh_type,
  97                    const unsigned char* prelocs,
  98                    size_t reloc_count,
  99                    Output_section* output_section,
 100                    bool needs_special_offset_handling,
 101                    unsigned char* view,
 102                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 103                    section_size_type view_size);
 104
 105   // Scan the relocs during a relocatable link.
 106   void
 107   scan_relocatable_relocs(const General_options& options,
 108                           Symbol_table* symtab,
 109                           Layout* layout,
 110                           Sized_relobj<64, false>* object,
 111                           unsigned int data_shndx,
 112                           unsigned int sh_type,
 113                           const unsigned char* prelocs,
 114                           size_t reloc_count,
 115                           Output_section* output_section,
 116                           bool needs_special_offset_handling,
 117                           size_t local_symbol_count,
 118                           const unsigned char* plocal_symbols,
 119                           Relocatable_relocs*);
 120
 121   // Relocate a section during a relocatable link.
 122   void
 123   relocate_for_relocatable(const Relocate_info<64, false>*,
 124                            unsigned int sh_type,
 125                            const unsigned char* prelocs,
 126                            size_t reloc_count,
 127                            Output_section* output_section,
 128                            off_t offset_in_output_section,
 129                            const Relocatable_relocs*,
 130                            unsigned char* view,
 131                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 132                            section_size_type view_size,
 133                            unsigned char* reloc_view,
 134                            section_size_type reloc_view_size);
 135
 136   // Return a string used to fill a code section with nops.
 137   std::string
 138   do_code_fill(section_size_type length) const;
 139
 140   // Return whether SYM is defined by the ABI.
 141   bool
 142   do_is_defined_by_abi(Symbol* sym) const
 143   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 144
 145   // Return the size of the GOT section.
 146   section_size_type
 147   got_size()
 148   {
 149     gold_assert(this->got_ != NULL);
 150     return this->got_->data_size();
 151   }
 152
 153  private:
 154   // The class which scans relocations.
 155   class Scan
 156   {
 157   public:
 158     Scan()
 159       : issued_non_pic_error_(false)
 160     { }
 161
 162     inline void
 163     local(const General_options& options, Symbol_table* symtab,
 164           Layout* layout, Target_x86_64* target,
 165           Sized_relobj<64, false>* object,
 166           unsigned int data_shndx,
 167           Output_section* output_section,
 168           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 169           const elfcpp::Sym<64, false>& lsym);
 170
 171     inline void
 172     global(const General_options& options, Symbol_table* symtab,
 173            Layout* layout, Target_x86_64* target,
 174            Sized_relobj<64, false>* object,
 175            unsigned int data_shndx,
 176            Output_section* output_section,
 177            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 178            Symbol* gsym);
 179
 180   private:
 181     static void
 182     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 183
 184     static void
 185     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 186                              Symbol*);
 187
 188     void
 189     check_non_pic(Relobj*, unsigned int r_type);
 190
 191     // Whether we have issued an error about a non-PIC compilation.
 192     bool issued_non_pic_error_;
 193   };
 194
 195   // The class which implements relocation.
 196   class Relocate
 197   {
 198    public:
 199     Relocate()
 200       : skip_call_tls_get_addr_(false)
 201     { }
 202
 203     ~Relocate()
 204     {
 205       if (this->skip_call_tls_get_addr_)
 206         {
 207           // FIXME: This needs to specify the location somehow.
 208           gold_error(_("missing expected TLS relocation"));
 209         }
 210     }
 211
 212     // Do a relocation.  Return false if the caller should not issue
 213     // any warnings about this relocation.
 214     inline bool
 215     relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum,
 216              const elfcpp::Rela<64, false>&,
 217              unsigned int r_type, const Sized_symbol<64>*,
 218              const Symbol_value<64>*,
 219              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 220              section_size_type);
 221
 222    private:
 223     // Do a TLS relocation.
 224     inline void
 225     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 226                  size_t relnum, const elfcpp::Rela<64, false>&,
 227                  unsigned int r_type, const Sized_symbol<64>*,
 228                  const Symbol_value<64>*,
 229                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 230                  section_size_type);
 231
 232     // Do a TLS General-Dynamic to Initial-Exec transition.
 233     inline void
 234     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 235                  Output_segment* tls_segment,
 236                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 237                  elfcpp::Elf_types<64>::Elf_Addr value,
 238                  unsigned char* view,
 239                  elfcpp::Elf_types<64>::Elf_Addr,
 240                  section_size_type view_size);
 241
 242     // Do a TLS General-Dynamic to Local-Exec transition.
 243     inline void
 244     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 245                  Output_segment* tls_segment,
 246                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 247                  elfcpp::Elf_types<64>::Elf_Addr value,
 248                  unsigned char* view,
 249                  section_size_type view_size);
 250
 251     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 252     inline void
 253     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 254                       Output_segment* tls_segment,
 255                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 256                       elfcpp::Elf_types<64>::Elf_Addr value,
 257                       unsigned char* view,
 258                       elfcpp::Elf_types<64>::Elf_Addr,
 259                       section_size_type view_size);
 260
 261     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 262     inline void
 263     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 264                       Output_segment* tls_segment,
 265                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 266                       elfcpp::Elf_types<64>::Elf_Addr value,
 267                       unsigned char* view,
 268                       section_size_type view_size);
 269
 270     // Do a TLS Local-Dynamic to Local-Exec transition.
 271     inline void
 272     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 273                  Output_segment* tls_segment,
 274                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 275                  elfcpp::Elf_types<64>::Elf_Addr value,
 276                  unsigned char* view,
 277                  section_size_type view_size);
 278
 279     // Do a TLS Initial-Exec to Local-Exec transition.
 280     static inline void
 281     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 282                  Output_segment* tls_segment,
 283                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 284                  elfcpp::Elf_types<64>::Elf_Addr value,
 285                  unsigned char* view,
 286                  section_size_type view_size);
 287
 288     // This is set if we should skip the next reloc, which should be a
 289     // PLT32 reloc against ___tls_get_addr.
 290     bool skip_call_tls_get_addr_;
 291   };
 292
 293   // A class which returns the size required for a relocation type,
 294   // used while scanning relocs during a relocatable link.
 295   class Relocatable_size_for_reloc
 296   {
 297    public:
 298     unsigned int
 299     get_size_for_reloc(unsigned int, Relobj*);
 300   };
 301
 302   // Adjust TLS relocation type based on the options and whether this
 303   // is a local symbol.
 304   static tls::Tls_optimization
 305   optimize_tls_reloc(bool is_final, int r_type);
 306
 307   // Get the GOT section, creating it if necessary.
 308   Output_data_got<64, false>*
 309   got_section(Symbol_table*, Layout*);
 310
 311   // Get the GOT PLT section.
 312   Output_data_space*
 313   got_plt_section() const
 314   {
 315     gold_assert(this->got_plt_ != NULL);
 316     return this->got_plt_;
 317   }
 318
 319   // Create the PLT section.
 320   void
 321   make_plt_section(Symbol_table* symtab, Layout* layout);
 322
 323   // Create a PLT entry for a global symbol.
 324   void
 325   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 326
 327   // Define the _TLS_MODULE_BASE_ symbol at the end of the TLS segment.
 328   void
 329   define_tls_base_symbol(Symbol_table*, Layout*);
 330
 331   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 332   void
 333   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 334
 335   // Create a GOT entry for the TLS module index.
 336   unsigned int
 337   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 338                       Sized_relobj<64, false>* object);
 339
 340   // Get the PLT section.
 341   Output_data_plt_x86_64*
 342   plt_section() const
 343   {
 344     gold_assert(this->plt_ != NULL);
 345     return this->plt_;
 346   }
 347
 348   // Get the dynamic reloc section, creating it if necessary.
 349   Reloc_section*
 350   rela_dyn_section(Layout*);
 351
 352   // Return true if the symbol may need a COPY relocation.
 353   // References from an executable object to non-function symbols
 354   // defined in a dynamic object may need a COPY relocation.
 355   bool
 356   may_need_copy_reloc(Symbol* gsym)
 357   {
 358     return (!parameters->options().shared()
 359             && gsym->is_from_dynobj()
 360             && gsym->type() != elfcpp::STT_FUNC);
 361   }
 362
 363   // Add a potential copy relocation.
 364   void
 365   copy_reloc(Symbol_table* symtab, Layout* layout, Relobj* object,
 366              unsigned int shndx, Output_section* output_section,
 367              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 368   {
 369     this->copy_relocs_.copy_reloc(symtab, layout,
 370                                   symtab->get_sized_symbol<64>(sym),
 371                                   object, shndx, output_section,
 372                                   reloc, this->rela_dyn_section(layout));
 373   }
 374
 375   // Information about this specific target which we pass to the
 376   // general Target structure.
 377   static const Target::Target_info x86_64_info;
 378
 379   enum Got_type
 380   {
 381     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 382     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 383     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 384     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 385   };
 386
 387   // The GOT section.
 388   Output_data_got<64, false>* got_;
 389   // The PLT section.
 390   Output_data_plt_x86_64* plt_;
 391   // The GOT PLT section.
 392   Output_data_space* got_plt_;
 393   // The dynamic reloc section.
 394   Reloc_section* rela_dyn_;
 395   // Relocs saved to avoid a COPY reloc.
 396   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 397   // Space for variables copied with a COPY reloc.
 398   Output_data_space* dynbss_;
 399   // Offset of the GOT entry for the TLS module index.
 400   unsigned int got_mod_index_offset_;
 401   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 402   bool tls_base_symbol_defined_;
 403 };
 404
 405 const Target::Target_info Target_x86_64::x86_64_info =
 406 {
 407   64,                   // size
 408   false,                // is_big_endian
 409   elfcpp::EM_X86_64,    // machine_code
 410   false,                // has_make_symbol
 411   false,                // has_resolve
 412   true,                 // has_code_fill
 413   true,                 // is_default_stack_executable
 414   '\0',                 // wrap_char
 415   "/lib/ld64.so.1",     // program interpreter
 416   0x400000,             // default_text_segment_address
 417   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 418   0x1000                // common_pagesize (overridable by -z common-page-size)
 419 };
 420
 421 // Get the GOT section, creating it if necessary.
 422
 423 Output_data_got<64, false>*
 424 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 425 {
 426   if (this->got_ == NULL)
 427     {
 428       gold_assert(symtab != NULL && layout != NULL);
 429
 430       this->got_ = new Output_data_got<64, false>();
 431
 432       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 433                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 434                                       this->got_);
 435
 436       // The old GNU linker creates a .got.plt section.  We just
 437       // create another set of data in the .got section.  Note that we
 438       // always create a PLT if we create a GOT, although the PLT
 439       // might be empty.
 440       this->got_plt_ = new Output_data_space(8);
 441       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 442                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 443                                       this->got_plt_);
 444
 445       // The first three entries are reserved.
 446       this->got_plt_->set_current_data_size(3 * 8);
 447
 448       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 449       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 450                                     this->got_plt_,
 451                                     0, 0, elfcpp::STT_OBJECT,
 452                                     elfcpp::STB_LOCAL,
 453                                     elfcpp::STV_HIDDEN, 0,
 454                                     false, false);
 455     }
 456
 457   return this->got_;
 458 }
 459
 460 // Get the dynamic reloc section, creating it if necessary.
 461
 462 Target_x86_64::Reloc_section*
 463 Target_x86_64::rela_dyn_section(Layout* layout)
 464 {
 465   if (this->rela_dyn_ == NULL)
 466     {
 467       gold_assert(layout != NULL);
 468       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 469       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 470                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 471     }
 472   return this->rela_dyn_;
 473 }
 474
 475 // A class to handle the PLT data.
 476
 477 class Output_data_plt_x86_64 : public Output_section_data
 478 {
 479  public:
 480   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 481
 482   Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
 483                          Output_data_space*);
 484
 485   // Add an entry to the PLT.
 486   void
 487   add_entry(Symbol* gsym);
 488
 489   // Add the reserved TLSDESC_PLT entry to the PLT.
 490   void
 491   reserve_tlsdesc_entry(unsigned int got_offset)
 492   { this->tlsdesc_got_offset_ = got_offset; }
 493
 494   // Return true if a TLSDESC_PLT entry has been reserved.
 495   bool
 496   has_tlsdesc_entry() const
 497   { return this->tlsdesc_got_offset_ != -1U; }
 498
 499   // Return the GOT offset for the reserved TLSDESC_PLT entry.
 500   unsigned int
 501   get_tlsdesc_got_offset() const
 502   { return this->tlsdesc_got_offset_; }
 503
 504   // Return the offset of the reserved TLSDESC_PLT entry.
 505   unsigned int
 506   get_tlsdesc_plt_offset() const
 507   { return (this->count_ + 1) * plt_entry_size; }
 508
 509   // Return the .rel.plt section data.
 510   const Reloc_section*
 511   rel_plt() const
 512   { return this->rel_; }
 513
 514  protected:
 515   void
 516   do_adjust_output_section(Output_section* os);
 517
 518  private:
 519   // The size of an entry in the PLT.
 520   static const int plt_entry_size = 16;
 521
 522   // The first entry in the PLT.
 523   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 524   // procedure linkage table for both programs and shared objects."
 525   static unsigned char first_plt_entry[plt_entry_size];
 526
 527   // Other entries in the PLT for an executable.
 528   static unsigned char plt_entry[plt_entry_size];
 529
 530   // The reserved TLSDESC entry in the PLT for an executable.
 531   static unsigned char tlsdesc_plt_entry[plt_entry_size];
 532
 533   // Set the final size.
 534   void
 535   set_final_data_size();
 536
 537   // Write out the PLT data.
 538   void
 539   do_write(Output_file*);
 540
 541   // The reloc section.
 542   Reloc_section* rel_;
 543   // The .got section.
 544   Output_data_got<64, false>* got_;
 545   // The .got.plt section.
 546   Output_data_space* got_plt_;
 547   // The number of PLT entries.
 548   unsigned int count_;
 549   // Offset of the reserved TLSDESC_GOT entry when needed.
 550   unsigned int tlsdesc_got_offset_;
 551 };
 552
 553 // Create the PLT section.  The ordinary .got section is an argument,
 554 // since we need to refer to the start.  We also create our own .got
 555 // section just for PLT entries.
 556
 557 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 558                                                Output_data_got<64, false>* got,
 559                                                Output_data_space* got_plt)
 560   : Output_section_data(8), got_(got), got_plt_(got_plt), count_(0),
 561     tlsdesc_got_offset_(-1U)
 562 {
 563   this->rel_ = new Reloc_section(false);
 564   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 565                                   elfcpp::SHF_ALLOC, this->rel_);
 566 }
 567
 568 void
 569 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 570 {
 571   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 572   // linker, and so do we.
 573   os->set_entsize(4);
 574 }
 575
 576 // Add an entry to the PLT.
 577
 578 void
 579 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 580 {
 581   gold_assert(!gsym->has_plt_offset());
 582
 583   // Note that when setting the PLT offset we skip the initial
 584   // reserved PLT entry.
 585   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 586
 587   ++this->count_;
 588
 589   section_offset_type got_offset = this->got_plt_->current_data_size();
 590
 591   // Every PLT entry needs a GOT entry which points back to the PLT
 592   // entry (this will be changed by the dynamic linker, normally
 593   // lazily when the function is called).
 594   this->got_plt_->set_current_data_size(got_offset + 8);
 595
 596   // Every PLT entry needs a reloc.
 597   gsym->set_needs_dynsym_entry();
 598   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 599                          got_offset, 0);
 600
 601   // Note that we don't need to save the symbol.  The contents of the
 602   // PLT are independent of which symbols are used.  The symbols only
 603   // appear in the relocations.
 604 }
 605
 606 // Set the final size.
 607 void
 608 Output_data_plt_x86_64::set_final_data_size()
 609 {
 610   unsigned int count = this->count_;
 611   if (this->has_tlsdesc_entry())
 612     ++count;
 613   this->set_data_size((count + 1) * plt_entry_size);
 614 }
 615
 616 // The first entry in the PLT for an executable.
 617
 618 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 619 {
 620   // From AMD64 ABI Draft 0.98, page 76
 621   0xff, 0x35,   // pushq contents of memory address
 622   0, 0, 0, 0,   // replaced with address of .got + 8
 623   0xff, 0x25,   // jmp indirect
 624   0, 0, 0, 0,   // replaced with address of .got + 16
 625   0x90, 0x90, 0x90, 0x90   // noop (x4)
 626 };
 627
 628 // Subsequent entries in the PLT for an executable.
 629
 630 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 631 {
 632   // From AMD64 ABI Draft 0.98, page 76
 633   0xff, 0x25,   // jmpq indirect
 634   0, 0, 0, 0,   // replaced with address of symbol in .got
 635   0x68,         // pushq immediate
 636   0, 0, 0, 0,   // replaced with offset into relocation table
 637   0xe9,         // jmpq relative
 638   0, 0, 0, 0    // replaced with offset to start of .plt
 639 };
 640
 641 // The reserved TLSDESC entry in the PLT for an executable.
 642
 643 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 644 {
 645   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 646   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 647   0xff, 0x35,   // pushq x(%rip)
 648   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 649   0xff, 0x25,   // jmpq *y(%rip)
 650   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 651   0x0f, 0x1f,   // nop
 652   0x40, 0
 653 };
 654
 655 // Write out the PLT.  This uses the hand-coded instructions above,
 656 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 657
 658 void
 659 Output_data_plt_x86_64::do_write(Output_file* of)
 660 {
 661   const off_t offset = this->offset();
 662   const section_size_type oview_size =
 663     convert_to_section_size_type(this->data_size());
 664   unsigned char* const oview = of->get_output_view(offset, oview_size);
 665
 666   const off_t got_file_offset = this->got_plt_->offset();
 667   const section_size_type got_size =
 668     convert_to_section_size_type(this->got_plt_->data_size());
 669   unsigned char* const got_view = of->get_output_view(got_file_offset,
 670                                                       got_size);
 671
 672   unsigned char* pov = oview;
 673
 674   // The base address of the .plt section.
 675   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 676   // The base address of the .got section.
 677   elfcpp::Elf_types<32>::Elf_Addr got_base = this->got_->address();
 678   // The base address of the PLT portion of the .got section,
 679   // which is where the GOT pointer will point, and where the
 680   // three reserved GOT entries are located.
 681   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 682
 683   memcpy(pov, first_plt_entry, plt_entry_size);
 684   // We do a jmp relative to the PC at the end of this instruction.
 685   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
 686                                               - (plt_address + 6));
 687   elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
 688                                     - (plt_address + 12));
 689   pov += plt_entry_size;
 690
 691   unsigned char* got_pov = got_view;
 692
 693   memset(got_pov, 0, 24);
 694   got_pov += 24;
 695
 696   unsigned int plt_offset = plt_entry_size;
 697   unsigned int got_offset = 24;
 698   const unsigned int count = this->count_;
 699   for (unsigned int plt_index = 0;
 700        plt_index < count;
 701        ++plt_index,
 702          pov += plt_entry_size,
 703          got_pov += 8,
 704          plt_offset += plt_entry_size,
 705          got_offset += 8)
 706     {
 707       // Set and adjust the PLT entry itself.
 708       memcpy(pov, plt_entry, plt_entry_size);
 709       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 710                                                   (got_address + got_offset
 711                                                    - (plt_address + plt_offset
 712                                                       + 6)));
 713
 714       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 715       elfcpp::Swap<32, false>::writeval(pov + 12,
 716                                         - (plt_offset + plt_entry_size));
 717
 718       // Set the entry in the GOT.
 719       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 720     }
 721
 722   if (this->has_tlsdesc_entry())
 723     {
 724       // Set and adjust the reserved TLSDESC PLT entry.
 725       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
 726       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
 727       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 728                                                   (got_address + 8
 729                                                    - (plt_address + plt_offset
 730                                                       + 6)));
 731       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
 732                                                   (got_base
 733                                                    + tlsdesc_got_offset
 734                                                    - (plt_address + plt_offset
 735                                                       + 12)));
 736       pov += plt_entry_size;
 737     }
 738
 739   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 740   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 741
 742   of->write_output_view(offset, oview_size, oview);
 743   of->write_output_view(got_file_offset, got_size, got_view);
 744 }
 745
 746 // Create the PLT section.
 747
 748 void
 749 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
 750 {
 751   if (this->plt_ == NULL)
 752     {
 753       // Create the GOT sections first.
 754       this->got_section(symtab, layout);
 755
 756       this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
 757                                               this->got_plt_);
 758       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 759                                       (elfcpp::SHF_ALLOC
 760                                        | elfcpp::SHF_EXECINSTR),
 761                                       this->plt_);
 762     }
 763 }
 764
 765 // Create a PLT entry for a global symbol.
 766
 767 void
 768 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 769                               Symbol* gsym)
 770 {
 771   if (gsym->has_plt_offset())
 772     return;
 773
 774   if (this->plt_ == NULL)
 775     this->make_plt_section(symtab, layout);
 776
 777   this->plt_->add_entry(gsym);
 778 }
 779
 780 // Define the _TLS_MODULE_BASE_ symbol at the end of the TLS segment.
 781
 782 void
 783 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
 784 {
 785   if (this->tls_base_symbol_defined_)
 786     return;
 787
 788   Output_segment* tls_segment = layout->tls_segment();
 789   if (tls_segment != NULL)
 790     {
 791       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
 792                                        tls_segment, 0, 0,
 793                                        elfcpp::STT_TLS,
 794                                        elfcpp::STB_LOCAL,
 795                                        elfcpp::STV_HIDDEN, 0,
 796                                        Symbol::SEGMENT_END, true);
 797     }
 798   this->tls_base_symbol_defined_ = true;
 799 }
 800
 801 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 802
 803 void
 804 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
 805                                              Layout* layout)
 806 {
 807   if (this->plt_ == NULL)
 808     this->make_plt_section(symtab, layout);
 809
 810   if (!this->plt_->has_tlsdesc_entry())
 811     {
 812       // Allocate the TLSDESC_GOT entry.
 813       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 814       unsigned int got_offset = got->add_constant(0);
 815
 816       // Allocate the TLSDESC_PLT entry.
 817       this->plt_->reserve_tlsdesc_entry(got_offset);
 818     }
 819 }
 820
 821 // Create a GOT entry for the TLS module index.
 822
 823 unsigned int
 824 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 825                                    Sized_relobj<64, false>* object)
 826 {
 827   if (this->got_mod_index_offset_ == -1U)
 828     {
 829       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 830       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 831       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 832       unsigned int got_offset = got->add_constant(0);
 833       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 834                           got_offset, 0);
 835       got->add_constant(0);
 836       this->got_mod_index_offset_ = got_offset;
 837     }
 838   return this->got_mod_index_offset_;
 839 }
 840
 841 // Optimize the TLS relocation type based on what we know about the
 842 // symbol.  IS_FINAL is true if the final address of this symbol is
 843 // known at link time.
 844
 845 tls::Tls_optimization
 846 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 847 {
 848   // If we are generating a shared library, then we can't do anything
 849   // in the linker.
 850   if (parameters->options().shared())
 851     return tls::TLSOPT_NONE;
 852
 853   switch (r_type)
 854     {
 855     case elfcpp::R_X86_64_TLSGD:
 856     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 857     case elfcpp::R_X86_64_TLSDESC_CALL:
 858       // These are General-Dynamic which permits fully general TLS
 859       // access.  Since we know that we are generating an executable,
 860       // we can convert this to Initial-Exec.  If we also know that
 861       // this is a local symbol, we can further switch to Local-Exec.
 862       if (is_final)
 863         return tls::TLSOPT_TO_LE;
 864       return tls::TLSOPT_TO_IE;
 865
 866     case elfcpp::R_X86_64_TLSLD:
 867       // This is Local-Dynamic, which refers to a local symbol in the
 868       // dynamic TLS block.  Since we know that we generating an
 869       // executable, we can switch to Local-Exec.
 870       return tls::TLSOPT_TO_LE;
 871
 872     case elfcpp::R_X86_64_DTPOFF32:
 873     case elfcpp::R_X86_64_DTPOFF64:
 874       // Another Local-Dynamic reloc.
 875       return tls::TLSOPT_TO_LE;
 876
 877     case elfcpp::R_X86_64_GOTTPOFF:
 878       // These are Initial-Exec relocs which get the thread offset
 879       // from the GOT.  If we know that we are linking against the
 880       // local symbol, we can switch to Local-Exec, which links the
 881       // thread offset into the instruction.
 882       if (is_final)
 883         return tls::TLSOPT_TO_LE;
 884       return tls::TLSOPT_NONE;
 885
 886     case elfcpp::R_X86_64_TPOFF32:
 887       // When we already have Local-Exec, there is nothing further we
 888       // can do.
 889       return tls::TLSOPT_NONE;
 890
 891     default:
 892       gold_unreachable();
 893     }
 894 }
 895
 896 // Report an unsupported relocation against a local symbol.
 897
 898 void
 899 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 900                                              unsigned int r_type)
 901 {
 902   gold_error(_("%s: unsupported reloc %u against local symbol"),
 903              object->name().c_str(), r_type);
 904 }
 905
 906 // We are about to emit a dynamic relocation of type R_TYPE.  If the
 907 // dynamic linker does not support it, issue an error.  The GNU linker
 908 // only issues a non-PIC error for an allocated read-only section.
 909 // Here we know the section is allocated, but we don't know that it is
 910 // read-only.  But we check for all the relocation types which the
 911 // glibc dynamic linker supports, so it seems appropriate to issue an
 912 // error even if the section is not read-only.
 913
 914 void
 915 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
 916 {
 917   switch (r_type)
 918     {
 919       // These are the relocation types supported by glibc for x86_64.
 920     case elfcpp::R_X86_64_RELATIVE:
 921     case elfcpp::R_X86_64_GLOB_DAT:
 922     case elfcpp::R_X86_64_JUMP_SLOT:
 923     case elfcpp::R_X86_64_DTPMOD64:
 924     case elfcpp::R_X86_64_DTPOFF64:
 925     case elfcpp::R_X86_64_TPOFF64:
 926     case elfcpp::R_X86_64_64:
 927     case elfcpp::R_X86_64_32:
 928     case elfcpp::R_X86_64_PC32:
 929     case elfcpp::R_X86_64_COPY:
 930       return;
 931
 932     default:
 933       // This prevents us from issuing more than one error per reloc
 934       // section.  But we can still wind up issuing more than one
 935       // error per object file.
 936       if (this->issued_non_pic_error_)
 937         return;
 938       object->error(_("requires unsupported dynamic reloc; "
 939                       "recompile with -fPIC"));
 940       this->issued_non_pic_error_ = true;
 941       return;
 942
 943     case elfcpp::R_X86_64_NONE:
 944       gold_unreachable();
 945     }
 946 }
 947
 948 // Scan a relocation for a local symbol.
 949
 950 inline void
 951 Target_x86_64::Scan::local(const General_options&,
 952                            Symbol_table* symtab,
 953                            Layout* layout,
 954                            Target_x86_64* target,
 955                            Sized_relobj<64, false>* object,
 956                            unsigned int data_shndx,
 957                            Output_section* output_section,
 958                            const elfcpp::Rela<64, false>& reloc,
 959                            unsigned int r_type,
 960                            const elfcpp::Sym<64, false>& lsym)
 961 {
 962   switch (r_type)
 963     {
 964     case elfcpp::R_X86_64_NONE:
 965     case elfcpp::R_386_GNU_VTINHERIT:
 966     case elfcpp::R_386_GNU_VTENTRY:
 967       break;
 968
 969     case elfcpp::R_X86_64_64:
 970       // If building a shared library (or a position-independent
 971       // executable), we need to create a dynamic relocation for this
 972       // location.  The relocation applied at link time will apply the
 973       // link-time value, so we flag the location with an
 974       // R_X86_64_RELATIVE relocation so the dynamic loader can
 975       // relocate it easily.
 976       if (parameters->options().output_is_position_independent())
 977         {
 978           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 979           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 980           rela_dyn->add_local_relative(object, r_sym,
 981                                        elfcpp::R_X86_64_RELATIVE,
 982                                        output_section, data_shndx,
 983                                        reloc.get_r_offset(),
 984                                        reloc.get_r_addend());
 985         }
 986       break;
 987
 988     case elfcpp::R_X86_64_32:
 989     case elfcpp::R_X86_64_32S:
 990     case elfcpp::R_X86_64_16:
 991     case elfcpp::R_X86_64_8:
 992       // If building a shared library (or a position-independent
 993       // executable), we need to create a dynamic relocation for this
 994       // location.  We can't use an R_X86_64_RELATIVE relocation
 995       // because that is always a 64-bit relocation.
 996       if (parameters->options().output_is_position_independent())
 997         {
 998           this->check_non_pic(object, r_type);
 999
1000           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1001           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1002           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1003             rela_dyn->add_local(object, r_sym, r_type, output_section,
1004                                 data_shndx, reloc.get_r_offset(),
1005                                 reloc.get_r_addend());
1006           else
1007             {
1008               gold_assert(lsym.get_st_value() == 0);
1009               unsigned int shndx = lsym.get_st_shndx();
1010               bool is_ordinary;
1011               shndx = object->adjust_sym_shndx(r_sym, shndx,
1012                                                &is_ordinary);
1013               if (!is_ordinary)
1014                 object->error(_("section symbol %u has bad shndx %u"),
1015                               r_sym, shndx);
1016               else
1017                 rela_dyn->add_local_section(object, shndx,
1018                                             r_type, output_section,
1019                                             data_shndx, reloc.get_r_offset(),
1020                                             reloc.get_r_addend());
1021             }
1022         }
1023       break;
1024
1025     case elfcpp::R_X86_64_PC64:
1026     case elfcpp::R_X86_64_PC32:
1027     case elfcpp::R_X86_64_PC16:
1028     case elfcpp::R_X86_64_PC8:
1029       break;
1030
1031     case elfcpp::R_X86_64_PLT32:
1032       // Since we know this is a local symbol, we can handle this as a
1033       // PC32 reloc.
1034       break;
1035
1036     case elfcpp::R_X86_64_GOTPC32:
1037     case elfcpp::R_X86_64_GOTOFF64:
1038     case elfcpp::R_X86_64_GOTPC64:
1039     case elfcpp::R_X86_64_PLTOFF64:
1040       // We need a GOT section.
1041       target->got_section(symtab, layout);
1042       // For PLTOFF64, we'd normally want a PLT section, but since we
1043       // know this is a local symbol, no PLT is needed.
1044       break;
1045
1046     case elfcpp::R_X86_64_GOT64:
1047     case elfcpp::R_X86_64_GOT32:
1048     case elfcpp::R_X86_64_GOTPCREL64:
1049     case elfcpp::R_X86_64_GOTPCREL:
1050     case elfcpp::R_X86_64_GOTPLT64:
1051       {
1052         // The symbol requires a GOT entry.
1053         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1054         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1055         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1056           {
1057             // If we are generating a shared object, we need to add a
1058             // dynamic relocation for this symbol's GOT entry.
1059             if (parameters->options().output_is_position_independent())
1060               {
1061                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1062                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1063                 if (r_type != elfcpp::R_X86_64_GOT32)
1064                   rela_dyn->add_local_relative(
1065                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
1066                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1067                 else
1068                   {
1069                     this->check_non_pic(object, r_type);
1070
1071                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1072                     rela_dyn->add_local(
1073                         object, r_sym, r_type, got,
1074                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1075                   }
1076               }
1077           }
1078         // For GOTPLT64, we'd normally want a PLT section, but since
1079         // we know this is a local symbol, no PLT is needed.
1080       }
1081       break;
1082
1083     case elfcpp::R_X86_64_COPY:
1084     case elfcpp::R_X86_64_GLOB_DAT:
1085     case elfcpp::R_X86_64_JUMP_SLOT:
1086     case elfcpp::R_X86_64_RELATIVE:
1087       // These are outstanding tls relocs, which are unexpected when linking
1088     case elfcpp::R_X86_64_TPOFF64:
1089     case elfcpp::R_X86_64_DTPMOD64:
1090     case elfcpp::R_X86_64_TLSDESC:
1091       gold_error(_("%s: unexpected reloc %u in object file"),
1092                  object->name().c_str(), r_type);
1093       break;
1094
1095       // These are initial tls relocs, which are expected when linking
1096     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1097     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1098     case elfcpp::R_X86_64_TLSDESC_CALL:
1099     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1100     case elfcpp::R_X86_64_DTPOFF32:
1101     case elfcpp::R_X86_64_DTPOFF64:
1102     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1103     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1104       {
1105         bool output_is_shared = parameters->options().shared();
1106         const tls::Tls_optimization optimized_type
1107             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1108         switch (r_type)
1109           {
1110           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1111             if (optimized_type == tls::TLSOPT_NONE)
1112               {
1113                 // Create a pair of GOT entries for the module index and
1114                 // dtv-relative offset.
1115                 Output_data_got<64, false>* got
1116                     = target->got_section(symtab, layout);
1117                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1118                 unsigned int shndx = lsym.get_st_shndx();
1119                 bool is_ordinary;
1120                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1121                 if (!is_ordinary)
1122                   object->error(_("local symbol %u has bad shndx %u"),
1123                               r_sym, shndx);
1124                 else
1125                   got->add_local_pair_with_rela(object, r_sym,
1126                                                 shndx,
1127                                                 GOT_TYPE_TLS_PAIR,
1128                                                 target->rela_dyn_section(layout),
1129                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1130               }
1131             else if (optimized_type != tls::TLSOPT_TO_LE)
1132               unsupported_reloc_local(object, r_type);
1133             break;
1134
1135           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1136             target->define_tls_base_symbol(symtab, layout);
1137             if (optimized_type == tls::TLSOPT_NONE)
1138               {
1139                 // Create reserved PLT and GOT entries for the resolver.
1140                 target->reserve_tlsdesc_entries(symtab, layout);
1141
1142                 // Generate a double GOT entry with an R_X86_64_TLSDESC reloc.
1143                 Output_data_got<64, false>* got
1144                     = target->got_section(symtab, layout);
1145                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1146                 unsigned int shndx = lsym.get_st_shndx();
1147                 bool is_ordinary;
1148                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1149                 if (!is_ordinary)
1150                   object->error(_("local symbol %u has bad shndx %u"),
1151                               r_sym, shndx);
1152                 else
1153                   got->add_local_pair_with_rela(object, r_sym,
1154                                                 shndx,
1155                                                 GOT_TYPE_TLS_DESC,
1156                                                 target->rela_dyn_section(layout),
1157                                                 elfcpp::R_X86_64_TLSDESC, 0);
1158               }
1159             else if (optimized_type != tls::TLSOPT_TO_LE)
1160               unsupported_reloc_local(object, r_type);
1161             break;
1162
1163           case elfcpp::R_X86_64_TLSDESC_CALL:
1164             break;
1165
1166           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1167             if (optimized_type == tls::TLSOPT_NONE)
1168               {
1169                 // Create a GOT entry for the module index.
1170                 target->got_mod_index_entry(symtab, layout, object);
1171               }
1172             else if (optimized_type != tls::TLSOPT_TO_LE)
1173               unsupported_reloc_local(object, r_type);
1174             break;
1175
1176           case elfcpp::R_X86_64_DTPOFF32:
1177           case elfcpp::R_X86_64_DTPOFF64:
1178             break;
1179
1180           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1181             layout->set_has_static_tls();
1182             if (optimized_type == tls::TLSOPT_NONE)
1183               {
1184                 // Create a GOT entry for the tp-relative offset.
1185                 Output_data_got<64, false>* got
1186                     = target->got_section(symtab, layout);
1187                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1188                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1189                                          target->rela_dyn_section(layout),
1190                                          elfcpp::R_X86_64_TPOFF64);
1191               }
1192             else if (optimized_type != tls::TLSOPT_TO_LE)
1193               unsupported_reloc_local(object, r_type);
1194             break;
1195
1196           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1197             layout->set_has_static_tls();
1198             if (output_is_shared)
1199               unsupported_reloc_local(object, r_type);
1200             break;
1201
1202           default:
1203             gold_unreachable();
1204           }
1205       }
1206       break;
1207
1208     case elfcpp::R_X86_64_SIZE32:
1209     case elfcpp::R_X86_64_SIZE64:
1210     default:
1211       gold_error(_("%s: unsupported reloc %u against local symbol"),
1212                  object->name().c_str(), r_type);
1213       break;
1214     }
1215 }
1216
1217
1218 // Report an unsupported relocation against a global symbol.
1219
1220 void
1221 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1222                                               unsigned int r_type,
1223                                               Symbol* gsym)
1224 {
1225   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1226              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1227 }
1228
1229 // Scan a relocation for a global symbol.
1230
1231 inline void
1232 Target_x86_64::Scan::global(const General_options&,
1233                             Symbol_table* symtab,
1234                             Layout* layout,
1235                             Target_x86_64* target,
1236                             Sized_relobj<64, false>* object,
1237                             unsigned int data_shndx,
1238                             Output_section* output_section,
1239                             const elfcpp::Rela<64, false>& reloc,
1240                             unsigned int r_type,
1241                             Symbol* gsym)
1242 {
1243   switch (r_type)
1244     {
1245     case elfcpp::R_X86_64_NONE:
1246     case elfcpp::R_386_GNU_VTINHERIT:
1247     case elfcpp::R_386_GNU_VTENTRY:
1248       break;
1249
1250     case elfcpp::R_X86_64_64:
1251     case elfcpp::R_X86_64_32:
1252     case elfcpp::R_X86_64_32S:
1253     case elfcpp::R_X86_64_16:
1254     case elfcpp::R_X86_64_8:
1255       {
1256         // Make a PLT entry if necessary.
1257         if (gsym->needs_plt_entry())
1258           {
1259             target->make_plt_entry(symtab, layout, gsym);
1260             // Since this is not a PC-relative relocation, we may be
1261             // taking the address of a function. In that case we need to
1262             // set the entry in the dynamic symbol table to the address of
1263             // the PLT entry.
1264             if (gsym->is_from_dynobj() && !parameters->options().shared())
1265               gsym->set_needs_dynsym_value();
1266           }
1267         // Make a dynamic relocation if necessary.
1268         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1269           {
1270             if (target->may_need_copy_reloc(gsym))
1271               {
1272                 target->copy_reloc(symtab, layout, object,
1273                                    data_shndx, output_section, gsym, reloc);
1274               }
1275             else if (r_type == elfcpp::R_X86_64_64
1276                      && gsym->can_use_relative_reloc(false))
1277               {
1278                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1279                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1280                                               output_section, object,
1281                                               data_shndx, reloc.get_r_offset(),
1282                                               reloc.get_r_addend());
1283               }
1284             else
1285               {
1286                 this->check_non_pic(object, r_type);
1287                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1288                 rela_dyn->add_global(gsym, r_type, output_section, object,
1289                                      data_shndx, reloc.get_r_offset(),
1290                                      reloc.get_r_addend());
1291               }
1292           }
1293       }
1294       break;
1295
1296     case elfcpp::R_X86_64_PC64:
1297     case elfcpp::R_X86_64_PC32:
1298     case elfcpp::R_X86_64_PC16:
1299     case elfcpp::R_X86_64_PC8:
1300       {
1301         // Make a PLT entry if necessary.
1302         if (gsym->needs_plt_entry())
1303           target->make_plt_entry(symtab, layout, gsym);
1304         // Make a dynamic relocation if necessary.
1305         int flags = Symbol::NON_PIC_REF;
1306         if (gsym->type() == elfcpp::STT_FUNC)
1307           flags |= Symbol::FUNCTION_CALL;
1308         if (gsym->needs_dynamic_reloc(flags))
1309           {
1310             if (target->may_need_copy_reloc(gsym))
1311               {
1312                 target->copy_reloc(symtab, layout, object,
1313                                    data_shndx, output_section, gsym, reloc);
1314               }
1315             else
1316               {
1317                 this->check_non_pic(object, r_type);
1318                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1319                 rela_dyn->add_global(gsym, r_type, output_section, object,
1320                                      data_shndx, reloc.get_r_offset(),
1321                                      reloc.get_r_addend());
1322               }
1323           }
1324       }
1325       break;
1326
1327     case elfcpp::R_X86_64_GOT64:
1328     case elfcpp::R_X86_64_GOT32:
1329     case elfcpp::R_X86_64_GOTPCREL64:
1330     case elfcpp::R_X86_64_GOTPCREL:
1331     case elfcpp::R_X86_64_GOTPLT64:
1332       {
1333         // The symbol requires a GOT entry.
1334         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1335         if (gsym->final_value_is_known())
1336           got->add_global(gsym, GOT_TYPE_STANDARD);
1337         else
1338           {
1339             // If this symbol is not fully resolved, we need to add a
1340             // dynamic relocation for it.
1341             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1342             if (gsym->is_from_dynobj()
1343                 || gsym->is_undefined()
1344                 || gsym->is_preemptible())
1345               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1346                                         elfcpp::R_X86_64_GLOB_DAT);
1347             else
1348               {
1349                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1350                   rela_dyn->add_global_relative(
1351                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1352                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1353               }
1354           }
1355         // For GOTPLT64, we also need a PLT entry (but only if the
1356         // symbol is not fully resolved).
1357         if (r_type == elfcpp::R_X86_64_GOTPLT64
1358             && !gsym->final_value_is_known())
1359           target->make_plt_entry(symtab, layout, gsym);
1360       }
1361       break;
1362
1363     case elfcpp::R_X86_64_PLT32:
1364       // If the symbol is fully resolved, this is just a PC32 reloc.
1365       // Otherwise we need a PLT entry.
1366       if (gsym->final_value_is_known())
1367         break;
1368       // If building a shared library, we can also skip the PLT entry
1369       // if the symbol is defined in the output file and is protected
1370       // or hidden.
1371       if (gsym->is_defined()
1372           && !gsym->is_from_dynobj()
1373           && !gsym->is_preemptible())
1374         break;
1375       target->make_plt_entry(symtab, layout, gsym);
1376       break;
1377
1378     case elfcpp::R_X86_64_GOTPC32:
1379     case elfcpp::R_X86_64_GOTOFF64:
1380     case elfcpp::R_X86_64_GOTPC64:
1381     case elfcpp::R_X86_64_PLTOFF64:
1382       // We need a GOT section.
1383       target->got_section(symtab, layout);
1384       // For PLTOFF64, we also need a PLT entry (but only if the
1385       // symbol is not fully resolved).
1386       if (r_type == elfcpp::R_X86_64_PLTOFF64
1387           && !gsym->final_value_is_known())
1388         target->make_plt_entry(symtab, layout, gsym);
1389       break;
1390
1391     case elfcpp::R_X86_64_COPY:
1392     case elfcpp::R_X86_64_GLOB_DAT:
1393     case elfcpp::R_X86_64_JUMP_SLOT:
1394     case elfcpp::R_X86_64_RELATIVE:
1395       // These are outstanding tls relocs, which are unexpected when linking
1396     case elfcpp::R_X86_64_TPOFF64:
1397     case elfcpp::R_X86_64_DTPMOD64:
1398     case elfcpp::R_X86_64_TLSDESC:
1399       gold_error(_("%s: unexpected reloc %u in object file"),
1400                  object->name().c_str(), r_type);
1401       break;
1402
1403       // These are initial tls relocs, which are expected for global()
1404     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1405     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1406     case elfcpp::R_X86_64_TLSDESC_CALL:
1407     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1408     case elfcpp::R_X86_64_DTPOFF32:
1409     case elfcpp::R_X86_64_DTPOFF64:
1410     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1411     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1412       {
1413         const bool is_final = gsym->final_value_is_known();
1414         const tls::Tls_optimization optimized_type
1415             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1416         switch (r_type)
1417           {
1418           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1419             if (optimized_type == tls::TLSOPT_NONE)
1420               {
1421                 // Create a pair of GOT entries for the module index and
1422                 // dtv-relative offset.
1423                 Output_data_got<64, false>* got
1424                     = target->got_section(symtab, layout);
1425                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1426                                                target->rela_dyn_section(layout),
1427                                                elfcpp::R_X86_64_DTPMOD64,
1428                                                elfcpp::R_X86_64_DTPOFF64);
1429               }
1430             else if (optimized_type == tls::TLSOPT_TO_IE)
1431               {
1432                 // Create a GOT entry for the tp-relative offset.
1433                 Output_data_got<64, false>* got
1434                     = target->got_section(symtab, layout);
1435                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1436                                           target->rela_dyn_section(layout),
1437                                           elfcpp::R_X86_64_TPOFF64);
1438               }
1439             else if (optimized_type != tls::TLSOPT_TO_LE)
1440               unsupported_reloc_global(object, r_type, gsym);
1441             break;
1442
1443           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1444             target->define_tls_base_symbol(symtab, layout);
1445             if (optimized_type == tls::TLSOPT_NONE)
1446               {
1447                 // Create reserved PLT and GOT entries for the resolver.
1448                 target->reserve_tlsdesc_entries(symtab, layout);
1449
1450                 // Create a double GOT entry with an R_X86_64_TLSDESC reloc.
1451                 Output_data_got<64, false>* got
1452                     = target->got_section(symtab, layout);
1453                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC,
1454                                                target->rela_dyn_section(layout),
1455                                                elfcpp::R_X86_64_TLSDESC, 0);
1456               }
1457             else if (optimized_type == tls::TLSOPT_TO_IE)
1458               {
1459                 // Create a GOT entry for the tp-relative offset.
1460                 Output_data_got<64, false>* got
1461                     = target->got_section(symtab, layout);
1462                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1463                                           target->rela_dyn_section(layout),
1464                                           elfcpp::R_X86_64_TPOFF64);
1465               }
1466             else if (optimized_type != tls::TLSOPT_TO_LE)
1467               unsupported_reloc_global(object, r_type, gsym);
1468             break;
1469
1470           case elfcpp::R_X86_64_TLSDESC_CALL:
1471             break;
1472
1473           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1474             if (optimized_type == tls::TLSOPT_NONE)
1475               {
1476                 // Create a GOT entry for the module index.
1477                 target->got_mod_index_entry(symtab, layout, object);
1478               }
1479             else if (optimized_type != tls::TLSOPT_TO_LE)
1480               unsupported_reloc_global(object, r_type, gsym);
1481             break;
1482
1483           case elfcpp::R_X86_64_DTPOFF32:
1484           case elfcpp::R_X86_64_DTPOFF64:
1485             break;
1486
1487           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1488             layout->set_has_static_tls();
1489             if (optimized_type == tls::TLSOPT_NONE)
1490               {
1491                 // Create a GOT entry for the tp-relative offset.
1492                 Output_data_got<64, false>* got
1493                     = target->got_section(symtab, layout);
1494                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1495                                           target->rela_dyn_section(layout),
1496                                           elfcpp::R_X86_64_TPOFF64);
1497               }
1498             else if (optimized_type != tls::TLSOPT_TO_LE)
1499               unsupported_reloc_global(object, r_type, gsym);
1500             break;
1501
1502           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1503             layout->set_has_static_tls();
1504             if (parameters->options().shared())
1505               unsupported_reloc_local(object, r_type);
1506             break;
1507
1508           default:
1509             gold_unreachable();
1510           }
1511       }
1512       break;
1513
1514     case elfcpp::R_X86_64_SIZE32:
1515     case elfcpp::R_X86_64_SIZE64:
1516     default:
1517       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1518                  object->name().c_str(), r_type,
1519                  gsym->demangled_name().c_str());
1520       break;
1521     }
1522 }
1523
1524 // Scan relocations for a section.
1525
1526 void
1527 Target_x86_64::scan_relocs(const General_options& options,
1528                            Symbol_table* symtab,
1529                            Layout* layout,
1530                            Sized_relobj<64, false>* object,
1531                            unsigned int data_shndx,
1532                            unsigned int sh_type,
1533                            const unsigned char* prelocs,
1534                            size_t reloc_count,
1535                            Output_section* output_section,
1536                            bool needs_special_offset_handling,
1537                            size_t local_symbol_count,
1538                            const unsigned char* plocal_symbols)
1539 {
1540   if (sh_type == elfcpp::SHT_REL)
1541     {
1542       gold_error(_("%s: unsupported REL reloc section"),
1543                  object->name().c_str());
1544       return;
1545     }
1546
1547   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1548       Target_x86_64::Scan>(
1549     options,
1550     symtab,
1551     layout,
1552     this,
1553     object,
1554     data_shndx,
1555     prelocs,
1556     reloc_count,
1557     output_section,
1558     needs_special_offset_handling,
1559     local_symbol_count,
1560     plocal_symbols);
1561 }
1562
1563 // Finalize the sections.
1564
1565 void
1566 Target_x86_64::do_finalize_sections(Layout* layout)
1567 {
1568   // Fill in some more dynamic tags.
1569   Output_data_dynamic* const odyn = layout->dynamic_data();
1570   if (odyn != NULL)
1571     {
1572       if (this->got_plt_ != NULL)
1573         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1574
1575       if (this->plt_ != NULL)
1576         {
1577           const Output_data* od = this->plt_->rel_plt();
1578           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1579           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1580           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1581           if (this->plt_->has_tlsdesc_entry())
1582             {
1583               unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
1584               unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
1585               this->got_->finalize_data_size();
1586               odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
1587                                             this->plt_, plt_offset);
1588               odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
1589                                             this->got_, got_offset);
1590             }
1591         }
1592
1593       if (this->rela_dyn_ != NULL)
1594         {
1595           const Output_data* od = this->rela_dyn_;
1596           odyn->add_section_address(elfcpp::DT_RELA, od);
1597           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1598           odyn->add_constant(elfcpp::DT_RELAENT,
1599                              elfcpp::Elf_sizes<64>::rela_size);
1600         }
1601
1602       if (!parameters->options().shared())
1603         {
1604           // The value of the DT_DEBUG tag is filled in by the dynamic
1605           // linker at run time, and used by the debugger.
1606           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1607         }
1608     }
1609
1610   // Emit any relocs we saved in an attempt to avoid generating COPY
1611   // relocs.
1612   if (this->copy_relocs_.any_saved_relocs())
1613     this->copy_relocs_.emit(this->rela_dyn_section(layout));
1614 }
1615
1616 // Perform a relocation.
1617
1618 inline bool
1619 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1620                                   Target_x86_64* target,
1621                                   size_t relnum,
1622                                   const elfcpp::Rela<64, false>& rela,
1623                                   unsigned int r_type,
1624                                   const Sized_symbol<64>* gsym,
1625                                   const Symbol_value<64>* psymval,
1626                                   unsigned char* view,
1627                                   elfcpp::Elf_types<64>::Elf_Addr address,
1628                                   section_size_type view_size)
1629 {
1630   if (this->skip_call_tls_get_addr_)
1631     {
1632       if (r_type != elfcpp::R_X86_64_PLT32
1633           || gsym == NULL
1634           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1635         {
1636           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1637                                  _("missing expected TLS relocation"));
1638         }
1639       else
1640         {
1641           this->skip_call_tls_get_addr_ = false;
1642           return false;
1643         }
1644     }
1645
1646   // Pick the value to use for symbols defined in shared objects.
1647   Symbol_value<64> symval;
1648   if (gsym != NULL
1649       && (gsym->is_from_dynobj()
1650           || (parameters->options().shared()
1651               && (gsym->is_undefined() || gsym->is_preemptible())))
1652       && gsym->has_plt_offset())
1653     {
1654       symval.set_output_value(target->plt_section()->address()
1655                               + gsym->plt_offset());
1656       psymval = &symval;
1657     }
1658
1659   const Sized_relobj<64, false>* object = relinfo->object;
1660   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1661
1662   // Get the GOT offset if needed.
1663   // The GOT pointer points to the end of the GOT section.
1664   // We need to subtract the size of the GOT section to get
1665   // the actual offset to use in the relocation.
1666   bool have_got_offset = false;
1667   unsigned int got_offset = 0;
1668   switch (r_type)
1669     {
1670     case elfcpp::R_X86_64_GOT32:
1671     case elfcpp::R_X86_64_GOT64:
1672     case elfcpp::R_X86_64_GOTPLT64:
1673     case elfcpp::R_X86_64_GOTPCREL:
1674     case elfcpp::R_X86_64_GOTPCREL64:
1675       if (gsym != NULL)
1676         {
1677           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1678           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1679         }
1680       else
1681         {
1682           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1683           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1684           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1685                         - target->got_size());
1686         }
1687       have_got_offset = true;
1688       break;
1689
1690     default:
1691       break;
1692     }
1693
1694   switch (r_type)
1695     {
1696     case elfcpp::R_X86_64_NONE:
1697     case elfcpp::R_386_GNU_VTINHERIT:
1698     case elfcpp::R_386_GNU_VTENTRY:
1699       break;
1700
1701     case elfcpp::R_X86_64_64:
1702       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1703       break;
1704
1705     case elfcpp::R_X86_64_PC64:
1706       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1707                                               address);
1708       break;
1709
1710     case elfcpp::R_X86_64_32:
1711       // FIXME: we need to verify that value + addend fits into 32 bits:
1712       //    uint64_t x = value + addend;
1713       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1714       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1715       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1716       break;
1717
1718     case elfcpp::R_X86_64_32S:
1719       // FIXME: we need to verify that value + addend fits into 32 bits:
1720       //    int64_t x = value + addend;   // note this quantity is signed!
1721       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1722       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1723       break;
1724
1725     case elfcpp::R_X86_64_PC32:
1726       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1727                                               address);
1728       break;
1729
1730     case elfcpp::R_X86_64_16:
1731       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1732       break;
1733
1734     case elfcpp::R_X86_64_PC16:
1735       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1736                                               address);
1737       break;
1738
1739     case elfcpp::R_X86_64_8:
1740       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1741       break;
1742
1743     case elfcpp::R_X86_64_PC8:
1744       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1745                                              address);
1746       break;
1747
1748     case elfcpp::R_X86_64_PLT32:
1749       gold_assert(gsym == NULL
1750                   || gsym->has_plt_offset()
1751                   || gsym->final_value_is_known()
1752                   || (gsym->is_defined()
1753                       && !gsym->is_from_dynobj()
1754                       && !gsym->is_preemptible()));
1755       // Note: while this code looks the same as for R_X86_64_PC32, it
1756       // behaves differently because psymval was set to point to
1757       // the PLT entry, rather than the symbol, in Scan::global().
1758       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1759                                               address);
1760       break;
1761
1762     case elfcpp::R_X86_64_PLTOFF64:
1763       {
1764         gold_assert(gsym);
1765         gold_assert(gsym->has_plt_offset()
1766                     || gsym->final_value_is_known());
1767         elfcpp::Elf_types<64>::Elf_Addr got_address;
1768         got_address = target->got_section(NULL, NULL)->address();
1769         Relocate_functions<64, false>::rela64(view, object, psymval,
1770                                               addend - got_address);
1771       }
1772
1773     case elfcpp::R_X86_64_GOT32:
1774       gold_assert(have_got_offset);
1775       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1776       break;
1777
1778     case elfcpp::R_X86_64_GOTPC32:
1779       {
1780         gold_assert(gsym);
1781         elfcpp::Elf_types<64>::Elf_Addr value;
1782         value = target->got_plt_section()->address();
1783         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1784       }
1785       break;
1786
1787     case elfcpp::R_X86_64_GOT64:
1788       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1789       // Since we always add a PLT entry, this is equivalent.
1790     case elfcpp::R_X86_64_GOTPLT64:
1791       gold_assert(have_got_offset);
1792       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1793       break;
1794
1795     case elfcpp::R_X86_64_GOTPC64:
1796       {
1797         gold_assert(gsym);
1798         elfcpp::Elf_types<64>::Elf_Addr value;
1799         value = target->got_plt_section()->address();
1800         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1801       }
1802       break;
1803
1804     case elfcpp::R_X86_64_GOTOFF64:
1805       {
1806         elfcpp::Elf_types<64>::Elf_Addr value;
1807         value = (psymval->value(object, 0)
1808                  - target->got_plt_section()->address());
1809         Relocate_functions<64, false>::rela64(view, value, addend);
1810       }
1811       break;
1812
1813     case elfcpp::R_X86_64_GOTPCREL:
1814       {
1815         gold_assert(have_got_offset);
1816         elfcpp::Elf_types<64>::Elf_Addr value;
1817         value = target->got_plt_section()->address() + got_offset;
1818         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1819       }
1820       break;
1821
1822     case elfcpp::R_X86_64_GOTPCREL64:
1823       {
1824         gold_assert(have_got_offset);
1825         elfcpp::Elf_types<64>::Elf_Addr value;
1826         value = target->got_plt_section()->address() + got_offset;
1827         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1828       }
1829       break;
1830
1831     case elfcpp::R_X86_64_COPY:
1832     case elfcpp::R_X86_64_GLOB_DAT:
1833     case elfcpp::R_X86_64_JUMP_SLOT:
1834     case elfcpp::R_X86_64_RELATIVE:
1835       // These are outstanding tls relocs, which are unexpected when linking
1836     case elfcpp::R_X86_64_TPOFF64:
1837     case elfcpp::R_X86_64_DTPMOD64:
1838     case elfcpp::R_X86_64_TLSDESC:
1839       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1840                              _("unexpected reloc %u in object file"),
1841                              r_type);
1842       break;
1843
1844       // These are initial tls relocs, which are expected when linking
1845     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1846     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1847     case elfcpp::R_X86_64_TLSDESC_CALL:
1848     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1849     case elfcpp::R_X86_64_DTPOFF32:
1850     case elfcpp::R_X86_64_DTPOFF64:
1851     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1852     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1853       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1854                          view, address, view_size);
1855       break;
1856
1857     case elfcpp::R_X86_64_SIZE32:
1858     case elfcpp::R_X86_64_SIZE64:
1859     default:
1860       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1861                              _("unsupported reloc %u"),
1862                              r_type);
1863       break;
1864     }
1865
1866   return true;
1867 }
1868
1869 // Perform a TLS relocation.
1870
1871 inline void
1872 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1873                                       Target_x86_64* target,
1874                                       size_t relnum,
1875                                       const elfcpp::Rela<64, false>& rela,
1876                                       unsigned int r_type,
1877                                       const Sized_symbol<64>* gsym,
1878                                       const Symbol_value<64>* psymval,
1879                                       unsigned char* view,
1880                                       elfcpp::Elf_types<64>::Elf_Addr address,
1881                                       section_size_type view_size)
1882 {
1883   Output_segment* tls_segment = relinfo->layout->tls_segment();
1884
1885   const Sized_relobj<64, false>* object = relinfo->object;
1886   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1887
1888   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1889
1890   const bool is_final = (gsym == NULL
1891                          ? !parameters->options().output_is_position_independent()
1892                          : gsym->final_value_is_known());
1893   const tls::Tls_optimization optimized_type
1894       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1895   switch (r_type)
1896     {
1897     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1898       if (optimized_type == tls::TLSOPT_TO_LE)
1899         {
1900           gold_assert(tls_segment != NULL);
1901           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1902                              rela, r_type, value, view,
1903                              view_size);
1904           break;
1905         }
1906       else
1907         {
1908           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1909                                    ? GOT_TYPE_TLS_OFFSET
1910                                    : GOT_TYPE_TLS_PAIR);
1911           unsigned int got_offset;
1912           if (gsym != NULL)
1913             {
1914               gold_assert(gsym->has_got_offset(got_type));
1915               got_offset = gsym->got_offset(got_type) - target->got_size();
1916             }
1917           else
1918             {
1919               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1920               gold_assert(object->local_has_got_offset(r_sym, got_type));
1921               got_offset = (object->local_got_offset(r_sym, got_type)
1922                             - target->got_size());
1923             }
1924           if (optimized_type == tls::TLSOPT_TO_IE)
1925             {
1926               gold_assert(tls_segment != NULL);
1927               value = target->got_plt_section()->address() + got_offset;
1928               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
1929                                  value, view, address, view_size);
1930               break;
1931             }
1932           else if (optimized_type == tls::TLSOPT_NONE)
1933             {
1934               // Relocate the field with the offset of the pair of GOT
1935               // entries.
1936               value = target->got_plt_section()->address() + got_offset;
1937               Relocate_functions<64, false>::pcrela32(view, value, addend,
1938                                                       address);
1939               break;
1940             }
1941         }
1942       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1943                              _("unsupported reloc %u"), r_type);
1944       break;
1945
1946     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1947     case elfcpp::R_X86_64_TLSDESC_CALL:
1948       if (optimized_type == tls::TLSOPT_TO_LE)
1949         {
1950           gold_assert(tls_segment != NULL);
1951           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
1952                                   rela, r_type, value, view,
1953                                   view_size);
1954           break;
1955         }
1956       else
1957         {
1958           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1959                                    ? GOT_TYPE_TLS_OFFSET
1960                                    : GOT_TYPE_TLS_DESC);
1961           unsigned int got_offset;
1962           if (gsym != NULL)
1963             {
1964               gold_assert(gsym->has_got_offset(got_type));
1965               got_offset = gsym->got_offset(got_type) - target->got_size();
1966             }
1967           else
1968             {
1969               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1970               gold_assert(object->local_has_got_offset(r_sym, got_type));
1971               got_offset = (object->local_got_offset(r_sym, got_type)
1972                             - target->got_size());
1973             }
1974           if (optimized_type == tls::TLSOPT_TO_IE)
1975             {
1976               gold_assert(tls_segment != NULL);
1977               value = target->got_plt_section()->address() + got_offset;
1978               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
1979                                       rela, r_type, value, view, address,
1980                                       view_size);
1981               break;
1982             }
1983           else if (optimized_type == tls::TLSOPT_NONE)
1984             {
1985               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
1986                 {
1987                   // Relocate the field with the offset of the pair of GOT
1988                   // entries.
1989                   value = target->got_plt_section()->address() + got_offset;
1990                   Relocate_functions<64, false>::pcrela32(view, value, addend,
1991                                                           address);
1992                 }
1993               break;
1994             }
1995         }
1996       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1997                              _("unsupported reloc %u"), r_type);
1998       break;
1999
2000     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2001       if (optimized_type == tls::TLSOPT_TO_LE)
2002         {
2003           gold_assert(tls_segment != NULL);
2004           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2005                              value, view, view_size);
2006           break;
2007         }
2008       else if (optimized_type == tls::TLSOPT_NONE)
2009         {
2010           // Relocate the field with the offset of the GOT entry for
2011           // the module index.
2012           unsigned int got_offset;
2013           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2014                         - target->got_size());
2015           value = target->got_plt_section()->address() + got_offset;
2016           Relocate_functions<64, false>::pcrela32(view, value, addend,
2017                                                   address);
2018           break;
2019         }
2020       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2021                              _("unsupported reloc %u"), r_type);
2022       break;
2023
2024     case elfcpp::R_X86_64_DTPOFF32:
2025       gold_assert(tls_segment != NULL);
2026       if (optimized_type == tls::TLSOPT_TO_LE)
2027         value -= tls_segment->memsz();
2028       Relocate_functions<64, false>::rela32(view, value, 0);
2029       break;
2030
2031     case elfcpp::R_X86_64_DTPOFF64:
2032       gold_assert(tls_segment != NULL);
2033       if (optimized_type == tls::TLSOPT_TO_LE)
2034         value -= tls_segment->memsz();
2035       Relocate_functions<64, false>::rela64(view, value, 0);
2036       break;
2037
2038     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2039       if (optimized_type == tls::TLSOPT_TO_LE)
2040         {
2041           gold_assert(tls_segment != NULL);
2042           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2043                                                 rela, r_type, value, view,
2044                                                 view_size);
2045           break;
2046         }
2047       else if (optimized_type == tls::TLSOPT_NONE)
2048         {
2049           // Relocate the field with the offset of the GOT entry for
2050           // the tp-relative offset of the symbol.
2051           unsigned int got_offset;
2052           if (gsym != NULL)
2053             {
2054               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2055               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2056                             - target->got_size());
2057             }
2058           else
2059             {
2060               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2061               gold_assert(object->local_has_got_offset(r_sym,
2062                                                        GOT_TYPE_TLS_OFFSET));
2063               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2064                             - target->got_size());
2065             }
2066           value = target->got_plt_section()->address() + got_offset;
2067           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2068           break;
2069         }
2070       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2071                              _("unsupported reloc type %u"),
2072                              r_type);
2073       break;
2074
2075     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2076       value -= tls_segment->memsz();
2077       Relocate_functions<64, false>::rela32(view, value, 0);
2078       break;
2079     }
2080 }
2081
2082 // Do a relocation in which we convert a TLS General-Dynamic to an
2083 // Initial-Exec.
2084
2085 inline void
2086 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2087                                       size_t relnum,
2088                                       Output_segment*,
2089                                       const elfcpp::Rela<64, false>& rela,
2090                                       unsigned int,
2091                                       elfcpp::Elf_types<64>::Elf_Addr value,
2092                                       unsigned char* view,
2093                                       elfcpp::Elf_types<64>::Elf_Addr address,
2094                                       section_size_type view_size)
2095 {
2096   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2097   // .word 0x6666; rex64; call __tls_get_addr
2098   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2099
2100   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2101   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2102
2103   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2104                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2105   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2106                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2107
2108   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2109
2110   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2111   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2112
2113   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2114   // We can skip it.
2115   this->skip_call_tls_get_addr_ = true;
2116 }
2117
2118 // Do a relocation in which we convert a TLS General-Dynamic to a
2119 // Local-Exec.
2120
2121 inline void
2122 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2123                                       size_t relnum,
2124                                       Output_segment* tls_segment,
2125                                       const elfcpp::Rela<64, false>& rela,
2126                                       unsigned int,
2127                                       elfcpp::Elf_types<64>::Elf_Addr value,
2128                                       unsigned char* view,
2129                                       section_size_type view_size)
2130 {
2131   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2132   // .word 0x6666; rex64; call __tls_get_addr
2133   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2134
2135   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2136   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2137
2138   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2139                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2140   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2141                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2142
2143   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2144
2145   value -= tls_segment->memsz();
2146   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2147
2148   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2149   // We can skip it.
2150   this->skip_call_tls_get_addr_ = true;
2151 }
2152
2153 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2154
2155 inline void
2156 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2157     const Relocate_info<64, false>* relinfo,
2158     size_t relnum,
2159     Output_segment*,
2160     const elfcpp::Rela<64, false>& rela,
2161     unsigned int r_type,
2162     elfcpp::Elf_types<64>::Elf_Addr value,
2163     unsigned char* view,
2164     elfcpp::Elf_types<64>::Elf_Addr address,
2165     section_size_type view_size)
2166 {
2167   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2168     {
2169       // leaq foo@tlsdesc(%rip), %rax
2170       // ==> movq foo@gottpoff(%rip), %rax
2171       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2172       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2173       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2174                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2175       view[-2] = 0x8b;
2176       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2177       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2178     }
2179   else
2180     {
2181       // call *foo@tlscall(%rax)
2182       // ==> nop; nop
2183       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2184       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2185       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2186                      view[0] == 0xff && view[1] == 0x10);
2187       view[0] = 0x66;
2188       view[1] = 0x90;
2189     }
2190 }
2191
2192 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2193
2194 inline void
2195 Target_x86_64::Relocate::tls_desc_gd_to_le(
2196     const Relocate_info<64, false>* relinfo,
2197     size_t relnum,
2198     Output_segment* tls_segment,
2199     const elfcpp::Rela<64, false>& rela,
2200     unsigned int r_type,
2201     elfcpp::Elf_types<64>::Elf_Addr value,
2202     unsigned char* view,
2203     section_size_type view_size)
2204 {
2205   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2206     {
2207       // leaq foo@tlsdesc(%rip), %rax
2208       // ==> movq foo@tpoff, %rax
2209       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2210       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2211       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2212                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2213       view[-2] = 0xc7;
2214       view[-1] = 0xc0;
2215       value -= tls_segment->memsz();
2216       Relocate_functions<64, false>::rela32(view, value, 0);
2217     }
2218   else
2219     {
2220       // call *foo@tlscall(%rax)
2221       // ==> nop; nop
2222       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2223       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2224       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2225                      view[0] == 0xff && view[1] == 0x10);
2226       view[0] = 0x66;
2227       view[1] = 0x90;
2228     }
2229 }
2230
2231 inline void
2232 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2233                                       size_t relnum,
2234                                       Output_segment*,
2235                                       const elfcpp::Rela<64, false>& rela,
2236                                       unsigned int,
2237                                       elfcpp::Elf_types<64>::Elf_Addr,
2238                                       unsigned char* view,
2239                                       section_size_type view_size)
2240 {
2241   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2242   // ... leq foo@dtpoff(%rax),%reg
2243   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2244
2245   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2246   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2247
2248   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2249                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2250
2251   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2252
2253   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2254
2255   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2256   // We can skip it.
2257   this->skip_call_tls_get_addr_ = true;
2258 }
2259
2260 // Do a relocation in which we convert a TLS Initial-Exec to a
2261 // Local-Exec.
2262
2263 inline void
2264 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2265                                       size_t relnum,
2266                                       Output_segment* tls_segment,
2267                                       const elfcpp::Rela<64, false>& rela,
2268                                       unsigned int,
2269                                       elfcpp::Elf_types<64>::Elf_Addr value,
2270                                       unsigned char* view,
2271                                       section_size_type view_size)
2272 {
2273   // We need to examine the opcodes to figure out which instruction we
2274   // are looking at.
2275
2276   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2277   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2278
2279   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2280   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2281
2282   unsigned char op1 = view[-3];
2283   unsigned char op2 = view[-2];
2284   unsigned char op3 = view[-1];
2285   unsigned char reg = op3 >> 3;
2286
2287   if (op2 == 0x8b)
2288     {
2289       // movq
2290       if (op1 == 0x4c)
2291         view[-3] = 0x49;
2292       view[-2] = 0xc7;
2293       view[-1] = 0xc0 | reg;
2294     }
2295   else if (reg == 4)
2296     {
2297       // Special handling for %rsp.
2298       if (op1 == 0x4c)
2299         view[-3] = 0x49;
2300       view[-2] = 0x81;
2301       view[-1] = 0xc0 | reg;
2302     }
2303   else
2304     {
2305       // addq
2306       if (op1 == 0x4c)
2307         view[-3] = 0x4d;
2308       view[-2] = 0x8d;
2309       view[-1] = 0x80 | reg | (reg << 3);
2310     }
2311
2312   value -= tls_segment->memsz();
2313   Relocate_functions<64, false>::rela32(view, value, 0);
2314 }
2315
2316 // Relocate section data.
2317
2318 void
2319 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
2320                                 unsigned int sh_type,
2321                                 const unsigned char* prelocs,
2322                                 size_t reloc_count,
2323                                 Output_section* output_section,
2324                                 bool needs_special_offset_handling,
2325                                 unsigned char* view,
2326                                 elfcpp::Elf_types<64>::Elf_Addr address,
2327                                 section_size_type view_size)
2328 {
2329   gold_assert(sh_type == elfcpp::SHT_RELA);
2330
2331   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2332                          Target_x86_64::Relocate>(
2333     relinfo,
2334     this,
2335     prelocs,
2336     reloc_count,
2337     output_section,
2338     needs_special_offset_handling,
2339     view,
2340     address,
2341     view_size);
2342 }
2343
2344 // Return the size of a relocation while scanning during a relocatable
2345 // link.
2346
2347 unsigned int
2348 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2349     unsigned int r_type,
2350     Relobj* object)
2351 {
2352   switch (r_type)
2353     {
2354     case elfcpp::R_X86_64_NONE:
2355     case elfcpp::R_386_GNU_VTINHERIT:
2356     case elfcpp::R_386_GNU_VTENTRY:
2357     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2358     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2359     case elfcpp::R_X86_64_TLSDESC_CALL:
2360     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2361     case elfcpp::R_X86_64_DTPOFF32:
2362     case elfcpp::R_X86_64_DTPOFF64:
2363     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2364     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2365       return 0;
2366
2367     case elfcpp::R_X86_64_64:
2368     case elfcpp::R_X86_64_PC64:
2369     case elfcpp::R_X86_64_GOTOFF64:
2370     case elfcpp::R_X86_64_GOTPC64:
2371     case elfcpp::R_X86_64_PLTOFF64:
2372     case elfcpp::R_X86_64_GOT64:
2373     case elfcpp::R_X86_64_GOTPCREL64:
2374     case elfcpp::R_X86_64_GOTPCREL:
2375     case elfcpp::R_X86_64_GOTPLT64:
2376       return 8;
2377
2378     case elfcpp::R_X86_64_32:
2379     case elfcpp::R_X86_64_32S:
2380     case elfcpp::R_X86_64_PC32:
2381     case elfcpp::R_X86_64_PLT32:
2382     case elfcpp::R_X86_64_GOTPC32:
2383     case elfcpp::R_X86_64_GOT32:
2384       return 4;
2385
2386     case elfcpp::R_X86_64_16:
2387     case elfcpp::R_X86_64_PC16:
2388       return 2;
2389
2390     case elfcpp::R_X86_64_8:
2391     case elfcpp::R_X86_64_PC8:
2392       return 1;
2393
2394     case elfcpp::R_X86_64_COPY:
2395     case elfcpp::R_X86_64_GLOB_DAT:
2396     case elfcpp::R_X86_64_JUMP_SLOT:
2397     case elfcpp::R_X86_64_RELATIVE:
2398       // These are outstanding tls relocs, which are unexpected when linking
2399     case elfcpp::R_X86_64_TPOFF64:
2400     case elfcpp::R_X86_64_DTPMOD64:
2401     case elfcpp::R_X86_64_TLSDESC:
2402       object->error(_("unexpected reloc %u in object file"), r_type);
2403       return 0;
2404
2405     case elfcpp::R_X86_64_SIZE32:
2406     case elfcpp::R_X86_64_SIZE64:
2407     default:
2408       object->error(_("unsupported reloc %u against local symbol"), r_type);
2409       return 0;
2410     }
2411 }
2412
2413 // Scan the relocs during a relocatable link.
2414
2415 void
2416 Target_x86_64::scan_relocatable_relocs(const General_options& options,
2417                                        Symbol_table* symtab,
2418                                        Layout* layout,
2419                                        Sized_relobj<64, false>* object,
2420                                        unsigned int data_shndx,
2421                                        unsigned int sh_type,
2422                                        const unsigned char* prelocs,
2423                                        size_t reloc_count,
2424                                        Output_section* output_section,
2425                                        bool needs_special_offset_handling,
2426                                        size_t local_symbol_count,
2427                                        const unsigned char* plocal_symbols,
2428                                        Relocatable_relocs* rr)
2429 {
2430   gold_assert(sh_type == elfcpp::SHT_RELA);
2431
2432   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2433     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2434
2435   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2436       Scan_relocatable_relocs>(
2437     options,
2438     symtab,
2439     layout,
2440     object,
2441     data_shndx,
2442     prelocs,
2443     reloc_count,
2444     output_section,
2445     needs_special_offset_handling,
2446     local_symbol_count,
2447     plocal_symbols,
2448     rr);
2449 }
2450
2451 // Relocate a section during a relocatable link.
2452
2453 void
2454 Target_x86_64::relocate_for_relocatable(
2455     const Relocate_info<64, false>* relinfo,
2456     unsigned int sh_type,
2457     const unsigned char* prelocs,
2458     size_t reloc_count,
2459     Output_section* output_section,
2460     off_t offset_in_output_section,
2461     const Relocatable_relocs* rr,
2462     unsigned char* view,
2463     elfcpp::Elf_types<64>::Elf_Addr view_address,
2464     section_size_type view_size,
2465     unsigned char* reloc_view,
2466     section_size_type reloc_view_size)
2467 {
2468   gold_assert(sh_type == elfcpp::SHT_RELA);
2469
2470   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2471     relinfo,
2472     prelocs,
2473     reloc_count,
2474     output_section,
2475     offset_in_output_section,
2476     rr,
2477     view,
2478     view_address,
2479     view_size,
2480     reloc_view,
2481     reloc_view_size);
2482 }
2483
2484 // Return the value to use for a dynamic which requires special
2485 // treatment.  This is how we support equality comparisons of function
2486 // pointers across shared library boundaries, as described in the
2487 // processor specific ABI supplement.
2488
2489 uint64_t
2490 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2491 {
2492   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2493   return this->plt_section()->address() + gsym->plt_offset();
2494 }
2495
2496 // Return a string used to fill a code section with nops to take up
2497 // the specified length.
2498
2499 std::string
2500 Target_x86_64::do_code_fill(section_size_type length) const
2501 {
2502   if (length >= 16)
2503     {
2504       // Build a jmpq instruction to skip over the bytes.
2505       unsigned char jmp[5];
2506       jmp[0] = 0xe9;
2507       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2508       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2509               + std::string(length - 5, '\0'));
2510     }
2511
2512   // Nop sequences of various lengths.
2513   const char nop1[1] = { 0x90 };                   // nop
2514   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2515   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2516   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2517   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2518                          0x00 };                   // leal 0(%esi,1),%esi
2519   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2520                          0x00, 0x00 };
2521   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2522                          0x00, 0x00, 0x00 };
2523   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2524                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2525   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2526                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2527                          0x00 };
2528   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2529                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2530                            0x00, 0x00 };
2531   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2532                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2533                            0x00, 0x00, 0x00 };
2534   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2535                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2536                            0x00, 0x00, 0x00, 0x00 };
2537   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2538                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2539                            0x27, 0x00, 0x00, 0x00,
2540                            0x00 };
2541   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2542                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2543                            0xbc, 0x27, 0x00, 0x00,
2544                            0x00, 0x00 };
2545   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2546                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2547                            0x90, 0x90, 0x90, 0x90,
2548                            0x90, 0x90, 0x90 };
2549
2550   const char* nops[16] = {
2551     NULL,
2552     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2553     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2554   };
2555
2556   return std::string(nops[length], length);
2557 }
2558
2559 // The selector for x86_64 object files.
2560
2561 class Target_selector_x86_64 : public Target_selector
2562 {
2563 public:
2564   Target_selector_x86_64()
2565     : Target_selector(elfcpp::EM_X86_64, 64, false, "elf64-x86-64")
2566   { }
2567
2568   Target*
2569   do_instantiate_target()
2570   { return new Target_x86_64(); }
2571 };
2572
2573 Target_selector_x86_64 target_selector_x86_64;
2574
2575 } // End anonymous namespace.