gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009 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   gc_process_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   // Scan the relocations to look for symbol adjustments.
  85   void
  86   scan_relocs(const General_options& options,
  87               Symbol_table* symtab,
  88               Layout* layout,
  89               Sized_relobj<64, false>* object,
  90               unsigned int data_shndx,
  91               unsigned int sh_type,
  92               const unsigned char* prelocs,
  93               size_t reloc_count,
  94               Output_section* output_section,
  95               bool needs_special_offset_handling,
  96               size_t local_symbol_count,
  97               const unsigned char* plocal_symbols);
  98
  99   // Finalize the sections.
 100   void
 101   do_finalize_sections(Layout*);
 102
 103   // Return the value to use for a dynamic which requires special
 104   // treatment.
 105   uint64_t
 106   do_dynsym_value(const Symbol*) const;
 107
 108   // Relocate a section.
 109   void
 110   relocate_section(const Relocate_info<64, false>*,
 111                    unsigned int sh_type,
 112                    const unsigned char* prelocs,
 113                    size_t reloc_count,
 114                    Output_section* output_section,
 115                    bool needs_special_offset_handling,
 116                    unsigned char* view,
 117                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 118                    section_size_type view_size);
 119
 120   // Scan the relocs during a relocatable link.
 121   void
 122   scan_relocatable_relocs(const General_options& options,
 123                           Symbol_table* symtab,
 124                           Layout* layout,
 125                           Sized_relobj<64, false>* object,
 126                           unsigned int data_shndx,
 127                           unsigned int sh_type,
 128                           const unsigned char* prelocs,
 129                           size_t reloc_count,
 130                           Output_section* output_section,
 131                           bool needs_special_offset_handling,
 132                           size_t local_symbol_count,
 133                           const unsigned char* plocal_symbols,
 134                           Relocatable_relocs*);
 135
 136   // Relocate a section during a relocatable link.
 137   void
 138   relocate_for_relocatable(const Relocate_info<64, false>*,
 139                            unsigned int sh_type,
 140                            const unsigned char* prelocs,
 141                            size_t reloc_count,
 142                            Output_section* output_section,
 143                            off_t offset_in_output_section,
 144                            const Relocatable_relocs*,
 145                            unsigned char* view,
 146                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 147                            section_size_type view_size,
 148                            unsigned char* reloc_view,
 149                            section_size_type reloc_view_size);
 150
 151   // Return a string used to fill a code section with nops.
 152   std::string
 153   do_code_fill(section_size_type length) const;
 154
 155   // Return whether SYM is defined by the ABI.
 156   bool
 157   do_is_defined_by_abi(const Symbol* sym) const
 158   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 159
 160   // Return the size of the GOT section.
 161   section_size_type
 162   got_size()
 163   {
 164     gold_assert(this->got_ != NULL);
 165     return this->got_->data_size();
 166   }
 167
 168  private:
 169   // The class which scans relocations.
 170   class Scan
 171   {
 172   public:
 173     Scan()
 174       : issued_non_pic_error_(false)
 175     { }
 176
 177     inline void
 178     local(const General_options& options, Symbol_table* symtab,
 179           Layout* layout, Target_x86_64* target,
 180           Sized_relobj<64, false>* object,
 181           unsigned int data_shndx,
 182           Output_section* output_section,
 183           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 184           const elfcpp::Sym<64, false>& lsym);
 185
 186     inline void
 187     global(const General_options& options, Symbol_table* symtab,
 188            Layout* layout, Target_x86_64* target,
 189            Sized_relobj<64, false>* object,
 190            unsigned int data_shndx,
 191            Output_section* output_section,
 192            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 193            Symbol* gsym);
 194
 195   private:
 196     static void
 197     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 198
 199     static void
 200     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 201                              Symbol*);
 202
 203     void
 204     check_non_pic(Relobj*, unsigned int r_type);
 205
 206     // Whether we have issued an error about a non-PIC compilation.
 207     bool issued_non_pic_error_;
 208   };
 209
 210   // The class which implements relocation.
 211   class Relocate
 212   {
 213    public:
 214     Relocate()
 215       : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
 216     { }
 217
 218     ~Relocate()
 219     {
 220       if (this->skip_call_tls_get_addr_)
 221         {
 222           // FIXME: This needs to specify the location somehow.
 223           gold_error(_("missing expected TLS relocation"));
 224         }
 225     }
 226
 227     // Do a relocation.  Return false if the caller should not issue
 228     // any warnings about this relocation.
 229     inline bool
 230     relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
 231              size_t relnum, const elfcpp::Rela<64, false>&,
 232              unsigned int r_type, const Sized_symbol<64>*,
 233              const Symbol_value<64>*,
 234              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 235              section_size_type);
 236
 237    private:
 238     // Do a TLS relocation.
 239     inline void
 240     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 241                  size_t relnum, const elfcpp::Rela<64, false>&,
 242                  unsigned int r_type, const Sized_symbol<64>*,
 243                  const Symbol_value<64>*,
 244                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 245                  section_size_type);
 246
 247     // Do a TLS General-Dynamic to Initial-Exec transition.
 248     inline void
 249     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 250                  Output_segment* tls_segment,
 251                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 252                  elfcpp::Elf_types<64>::Elf_Addr value,
 253                  unsigned char* view,
 254                  elfcpp::Elf_types<64>::Elf_Addr,
 255                  section_size_type view_size);
 256
 257     // Do a TLS General-Dynamic to Local-Exec transition.
 258     inline void
 259     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 260                  Output_segment* tls_segment,
 261                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 262                  elfcpp::Elf_types<64>::Elf_Addr value,
 263                  unsigned char* view,
 264                  section_size_type view_size);
 265
 266     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 267     inline void
 268     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 269                       Output_segment* tls_segment,
 270                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 271                       elfcpp::Elf_types<64>::Elf_Addr value,
 272                       unsigned char* view,
 273                       elfcpp::Elf_types<64>::Elf_Addr,
 274                       section_size_type view_size);
 275
 276     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 277     inline void
 278     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 279                       Output_segment* tls_segment,
 280                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 281                       elfcpp::Elf_types<64>::Elf_Addr value,
 282                       unsigned char* view,
 283                       section_size_type view_size);
 284
 285     // Do a TLS Local-Dynamic to Local-Exec transition.
 286     inline void
 287     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 288                  Output_segment* tls_segment,
 289                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 290                  elfcpp::Elf_types<64>::Elf_Addr value,
 291                  unsigned char* view,
 292                  section_size_type view_size);
 293
 294     // Do a TLS Initial-Exec to Local-Exec transition.
 295     static inline void
 296     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 297                  Output_segment* tls_segment,
 298                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 299                  elfcpp::Elf_types<64>::Elf_Addr value,
 300                  unsigned char* view,
 301                  section_size_type view_size);
 302
 303     // This is set if we should skip the next reloc, which should be a
 304     // PLT32 reloc against ___tls_get_addr.
 305     bool skip_call_tls_get_addr_;
 306
 307     // This is set if we see a relocation which could load the address
 308     // of the TLS block.  Whether we see such a relocation determines
 309     // how we handle the R_X86_64_DTPOFF32 relocation, which is used
 310     // in debugging sections.
 311     bool saw_tls_block_reloc_;
 312   };
 313
 314   // A class which returns the size required for a relocation type,
 315   // used while scanning relocs during a relocatable link.
 316   class Relocatable_size_for_reloc
 317   {
 318    public:
 319     unsigned int
 320     get_size_for_reloc(unsigned int, Relobj*);
 321   };
 322
 323   // Adjust TLS relocation type based on the options and whether this
 324   // is a local symbol.
 325   static tls::Tls_optimization
 326   optimize_tls_reloc(bool is_final, int r_type);
 327
 328   // Get the GOT section, creating it if necessary.
 329   Output_data_got<64, false>*
 330   got_section(Symbol_table*, Layout*);
 331
 332   // Get the GOT PLT section.
 333   Output_data_space*
 334   got_plt_section() const
 335   {
 336     gold_assert(this->got_plt_ != NULL);
 337     return this->got_plt_;
 338   }
 339
 340   // Create the PLT section.
 341   void
 342   make_plt_section(Symbol_table* symtab, Layout* layout);
 343
 344   // Create a PLT entry for a global symbol.
 345   void
 346   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 347
 348   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 349   void
 350   define_tls_base_symbol(Symbol_table*, Layout*);
 351
 352   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 353   void
 354   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 355
 356   // Create a GOT entry for the TLS module index.
 357   unsigned int
 358   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 359                       Sized_relobj<64, false>* object);
 360
 361   // Get the PLT section.
 362   Output_data_plt_x86_64*
 363   plt_section() const
 364   {
 365     gold_assert(this->plt_ != NULL);
 366     return this->plt_;
 367   }
 368
 369   // Get the dynamic reloc section, creating it if necessary.
 370   Reloc_section*
 371   rela_dyn_section(Layout*);
 372
 373   // Return true if the symbol may need a COPY relocation.
 374   // References from an executable object to non-function symbols
 375   // defined in a dynamic object may need a COPY relocation.
 376   bool
 377   may_need_copy_reloc(Symbol* gsym)
 378   {
 379     return (!parameters->options().shared()
 380             && gsym->is_from_dynobj()
 381             && gsym->type() != elfcpp::STT_FUNC);
 382   }
 383
 384   // Add a potential copy relocation.
 385   void
 386   copy_reloc(Symbol_table* symtab, Layout* layout,
 387              Sized_relobj<64, false>* object,
 388              unsigned int shndx, Output_section* output_section,
 389              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 390   {
 391     this->copy_relocs_.copy_reloc(symtab, layout,
 392                                   symtab->get_sized_symbol<64>(sym),
 393                                   object, shndx, output_section,
 394                                   reloc, this->rela_dyn_section(layout));
 395   }
 396
 397   // Information about this specific target which we pass to the
 398   // general Target structure.
 399   static const Target::Target_info x86_64_info;
 400
 401   enum Got_type
 402   {
 403     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 404     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 405     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 406     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 407   };
 408
 409   // The GOT section.
 410   Output_data_got<64, false>* got_;
 411   // The PLT section.
 412   Output_data_plt_x86_64* plt_;
 413   // The GOT PLT section.
 414   Output_data_space* got_plt_;
 415   // The dynamic reloc section.
 416   Reloc_section* rela_dyn_;
 417   // Relocs saved to avoid a COPY reloc.
 418   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 419   // Space for variables copied with a COPY reloc.
 420   Output_data_space* dynbss_;
 421   // Offset of the GOT entry for the TLS module index.
 422   unsigned int got_mod_index_offset_;
 423   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 424   bool tls_base_symbol_defined_;
 425 };
 426
 427 const Target::Target_info Target_x86_64::x86_64_info =
 428 {
 429   64,                   // size
 430   false,                // is_big_endian
 431   elfcpp::EM_X86_64,    // machine_code
 432   false,                // has_make_symbol
 433   false,                // has_resolve
 434   true,                 // has_code_fill
 435   true,                 // is_default_stack_executable
 436   '\0',                 // wrap_char
 437   "/lib/ld64.so.1",     // program interpreter
 438   0x400000,             // default_text_segment_address
 439   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 440   0x1000                // common_pagesize (overridable by -z common-page-size)
 441 };
 442
 443 // Get the GOT section, creating it if necessary.
 444
 445 Output_data_got<64, false>*
 446 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 447 {
 448   if (this->got_ == NULL)
 449     {
 450       gold_assert(symtab != NULL && layout != NULL);
 451
 452       this->got_ = new Output_data_got<64, false>();
 453
 454       Output_section* os;
 455       os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 456                                            (elfcpp::SHF_ALLOC
 457                                             | elfcpp::SHF_WRITE),
 458                                            this->got_);
 459       os->set_is_relro();
 460
 461       // The old GNU linker creates a .got.plt section.  We just
 462       // create another set of data in the .got section.  Note that we
 463       // always create a PLT if we create a GOT, although the PLT
 464       // might be empty.
 465       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 466       os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 467                                            (elfcpp::SHF_ALLOC
 468                                             | elfcpp::SHF_WRITE),
 469                                            this->got_plt_);
 470       os->set_is_relro();
 471
 472       // The first three entries are reserved.
 473       this->got_plt_->set_current_data_size(3 * 8);
 474
 475       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 476       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 477                                     this->got_plt_,
 478                                     0, 0, elfcpp::STT_OBJECT,
 479                                     elfcpp::STB_LOCAL,
 480                                     elfcpp::STV_HIDDEN, 0,
 481                                     false, false);
 482     }
 483
 484   return this->got_;
 485 }
 486
 487 // Get the dynamic reloc section, creating it if necessary.
 488
 489 Target_x86_64::Reloc_section*
 490 Target_x86_64::rela_dyn_section(Layout* layout)
 491 {
 492   if (this->rela_dyn_ == NULL)
 493     {
 494       gold_assert(layout != NULL);
 495       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 496       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 497                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 498     }
 499   return this->rela_dyn_;
 500 }
 501
 502 // A class to handle the PLT data.
 503
 504 class Output_data_plt_x86_64 : public Output_section_data
 505 {
 506  public:
 507   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 508
 509   Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
 510                          Output_data_space*);
 511
 512   // Add an entry to the PLT.
 513   void
 514   add_entry(Symbol* gsym);
 515
 516   // Add the reserved TLSDESC_PLT entry to the PLT.
 517   void
 518   reserve_tlsdesc_entry(unsigned int got_offset)
 519   { this->tlsdesc_got_offset_ = got_offset; }
 520
 521   // Return true if a TLSDESC_PLT entry has been reserved.
 522   bool
 523   has_tlsdesc_entry() const
 524   { return this->tlsdesc_got_offset_ != -1U; }
 525
 526   // Return the GOT offset for the reserved TLSDESC_PLT entry.
 527   unsigned int
 528   get_tlsdesc_got_offset() const
 529   { return this->tlsdesc_got_offset_; }
 530
 531   // Return the offset of the reserved TLSDESC_PLT entry.
 532   unsigned int
 533   get_tlsdesc_plt_offset() const
 534   { return (this->count_ + 1) * plt_entry_size; }
 535
 536   // Return the .rel.plt section data.
 537   const Reloc_section*
 538   rel_plt() const
 539   { return this->rel_; }
 540
 541  protected:
 542   void
 543   do_adjust_output_section(Output_section* os);
 544
 545   // Write to a map file.
 546   void
 547   do_print_to_mapfile(Mapfile* mapfile) const
 548   { mapfile->print_output_data(this, _("** PLT")); }
 549
 550  private:
 551   // The size of an entry in the PLT.
 552   static const int plt_entry_size = 16;
 553
 554   // The first entry in the PLT.
 555   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 556   // procedure linkage table for both programs and shared objects."
 557   static unsigned char first_plt_entry[plt_entry_size];
 558
 559   // Other entries in the PLT for an executable.
 560   static unsigned char plt_entry[plt_entry_size];
 561
 562   // The reserved TLSDESC entry in the PLT for an executable.
 563   static unsigned char tlsdesc_plt_entry[plt_entry_size];
 564
 565   // Set the final size.
 566   void
 567   set_final_data_size();
 568
 569   // Write out the PLT data.
 570   void
 571   do_write(Output_file*);
 572
 573   // The reloc section.
 574   Reloc_section* rel_;
 575   // The .got section.
 576   Output_data_got<64, false>* got_;
 577   // The .got.plt section.
 578   Output_data_space* got_plt_;
 579   // The number of PLT entries.
 580   unsigned int count_;
 581   // Offset of the reserved TLSDESC_GOT entry when needed.
 582   unsigned int tlsdesc_got_offset_;
 583 };
 584
 585 // Create the PLT section.  The ordinary .got section is an argument,
 586 // since we need to refer to the start.  We also create our own .got
 587 // section just for PLT entries.
 588
 589 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 590                                                Output_data_got<64, false>* got,
 591                                                Output_data_space* got_plt)
 592   : Output_section_data(8), got_(got), got_plt_(got_plt), count_(0),
 593     tlsdesc_got_offset_(-1U)
 594 {
 595   this->rel_ = new Reloc_section(false);
 596   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 597                                   elfcpp::SHF_ALLOC, this->rel_);
 598 }
 599
 600 void
 601 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 602 {
 603   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 604   // linker, and so do we.
 605   os->set_entsize(4);
 606 }
 607
 608 // Add an entry to the PLT.
 609
 610 void
 611 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 612 {
 613   gold_assert(!gsym->has_plt_offset());
 614
 615   // Note that when setting the PLT offset we skip the initial
 616   // reserved PLT entry.
 617   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 618
 619   ++this->count_;
 620
 621   section_offset_type got_offset = this->got_plt_->current_data_size();
 622
 623   // Every PLT entry needs a GOT entry which points back to the PLT
 624   // entry (this will be changed by the dynamic linker, normally
 625   // lazily when the function is called).
 626   this->got_plt_->set_current_data_size(got_offset + 8);
 627
 628   // Every PLT entry needs a reloc.
 629   gsym->set_needs_dynsym_entry();
 630   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 631                          got_offset, 0);
 632
 633   // Note that we don't need to save the symbol.  The contents of the
 634   // PLT are independent of which symbols are used.  The symbols only
 635   // appear in the relocations.
 636 }
 637
 638 // Set the final size.
 639 void
 640 Output_data_plt_x86_64::set_final_data_size()
 641 {
 642   unsigned int count = this->count_;
 643   if (this->has_tlsdesc_entry())
 644     ++count;
 645   this->set_data_size((count + 1) * plt_entry_size);
 646 }
 647
 648 // The first entry in the PLT for an executable.
 649
 650 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 651 {
 652   // From AMD64 ABI Draft 0.98, page 76
 653   0xff, 0x35,   // pushq contents of memory address
 654   0, 0, 0, 0,   // replaced with address of .got + 8
 655   0xff, 0x25,   // jmp indirect
 656   0, 0, 0, 0,   // replaced with address of .got + 16
 657   0x90, 0x90, 0x90, 0x90   // noop (x4)
 658 };
 659
 660 // Subsequent entries in the PLT for an executable.
 661
 662 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 663 {
 664   // From AMD64 ABI Draft 0.98, page 76
 665   0xff, 0x25,   // jmpq indirect
 666   0, 0, 0, 0,   // replaced with address of symbol in .got
 667   0x68,         // pushq immediate
 668   0, 0, 0, 0,   // replaced with offset into relocation table
 669   0xe9,         // jmpq relative
 670   0, 0, 0, 0    // replaced with offset to start of .plt
 671 };
 672
 673 // The reserved TLSDESC entry in the PLT for an executable.
 674
 675 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 676 {
 677   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 678   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 679   0xff, 0x35,   // pushq x(%rip)
 680   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 681   0xff, 0x25,   // jmpq *y(%rip)
 682   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 683   0x0f, 0x1f,   // nop
 684   0x40, 0
 685 };
 686
 687 // Write out the PLT.  This uses the hand-coded instructions above,
 688 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 689
 690 void
 691 Output_data_plt_x86_64::do_write(Output_file* of)
 692 {
 693   const off_t offset = this->offset();
 694   const section_size_type oview_size =
 695     convert_to_section_size_type(this->data_size());
 696   unsigned char* const oview = of->get_output_view(offset, oview_size);
 697
 698   const off_t got_file_offset = this->got_plt_->offset();
 699   const section_size_type got_size =
 700     convert_to_section_size_type(this->got_plt_->data_size());
 701   unsigned char* const got_view = of->get_output_view(got_file_offset,
 702                                                       got_size);
 703
 704   unsigned char* pov = oview;
 705
 706   // The base address of the .plt section.
 707   elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
 708   // The base address of the .got section.
 709   elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
 710   // The base address of the PLT portion of the .got section,
 711   // which is where the GOT pointer will point, and where the
 712   // three reserved GOT entries are located.
 713   elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
 714
 715   memcpy(pov, first_plt_entry, plt_entry_size);
 716   // We do a jmp relative to the PC at the end of this instruction.
 717   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 718                                               (got_address + 8
 719                                                - (plt_address + 6)));
 720   elfcpp::Swap<32, false>::writeval(pov + 8,
 721                                     (got_address + 16
 722                                      - (plt_address + 12)));
 723   pov += plt_entry_size;
 724
 725   unsigned char* got_pov = got_view;
 726
 727   memset(got_pov, 0, 24);
 728   got_pov += 24;
 729
 730   unsigned int plt_offset = plt_entry_size;
 731   unsigned int got_offset = 24;
 732   const unsigned int count = this->count_;
 733   for (unsigned int plt_index = 0;
 734        plt_index < count;
 735        ++plt_index,
 736          pov += plt_entry_size,
 737          got_pov += 8,
 738          plt_offset += plt_entry_size,
 739          got_offset += 8)
 740     {
 741       // Set and adjust the PLT entry itself.
 742       memcpy(pov, plt_entry, plt_entry_size);
 743       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 744                                                   (got_address + got_offset
 745                                                    - (plt_address + plt_offset
 746                                                       + 6)));
 747
 748       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 749       elfcpp::Swap<32, false>::writeval(pov + 12,
 750                                         - (plt_offset + plt_entry_size));
 751
 752       // Set the entry in the GOT.
 753       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 754     }
 755
 756   if (this->has_tlsdesc_entry())
 757     {
 758       // Set and adjust the reserved TLSDESC PLT entry.
 759       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
 760       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
 761       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 762                                                   (got_address + 8
 763                                                    - (plt_address + plt_offset
 764                                                       + 6)));
 765       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
 766                                                   (got_base
 767                                                    + tlsdesc_got_offset
 768                                                    - (plt_address + plt_offset
 769                                                       + 12)));
 770       pov += plt_entry_size;
 771     }
 772
 773   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 774   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 775
 776   of->write_output_view(offset, oview_size, oview);
 777   of->write_output_view(got_file_offset, got_size, got_view);
 778 }
 779
 780 // Create the PLT section.
 781
 782 void
 783 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
 784 {
 785   if (this->plt_ == NULL)
 786     {
 787       // Create the GOT sections first.
 788       this->got_section(symtab, layout);
 789
 790       this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
 791                                               this->got_plt_);
 792       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 793                                       (elfcpp::SHF_ALLOC
 794                                        | elfcpp::SHF_EXECINSTR),
 795                                       this->plt_);
 796     }
 797 }
 798
 799 // Create a PLT entry for a global symbol.
 800
 801 void
 802 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 803                               Symbol* gsym)
 804 {
 805   if (gsym->has_plt_offset())
 806     return;
 807
 808   if (this->plt_ == NULL)
 809     this->make_plt_section(symtab, layout);
 810
 811   this->plt_->add_entry(gsym);
 812 }
 813
 814 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 815
 816 void
 817 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
 818 {
 819   if (this->tls_base_symbol_defined_)
 820     return;
 821
 822   Output_segment* tls_segment = layout->tls_segment();
 823   if (tls_segment != NULL)
 824     {
 825       bool is_exec = parameters->options().output_is_executable();
 826       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
 827                                        tls_segment, 0, 0,
 828                                        elfcpp::STT_TLS,
 829                                        elfcpp::STB_LOCAL,
 830                                        elfcpp::STV_HIDDEN, 0,
 831                                        (is_exec
 832                                         ? Symbol::SEGMENT_END
 833                                         : Symbol::SEGMENT_START),
 834                                        true);
 835     }
 836   this->tls_base_symbol_defined_ = true;
 837 }
 838
 839 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 840
 841 void
 842 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
 843                                              Layout* layout)
 844 {
 845   if (this->plt_ == NULL)
 846     this->make_plt_section(symtab, layout);
 847
 848   if (!this->plt_->has_tlsdesc_entry())
 849     {
 850       // Allocate the TLSDESC_GOT entry.
 851       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 852       unsigned int got_offset = got->add_constant(0);
 853
 854       // Allocate the TLSDESC_PLT entry.
 855       this->plt_->reserve_tlsdesc_entry(got_offset);
 856     }
 857 }
 858
 859 // Create a GOT entry for the TLS module index.
 860
 861 unsigned int
 862 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 863                                    Sized_relobj<64, false>* object)
 864 {
 865   if (this->got_mod_index_offset_ == -1U)
 866     {
 867       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 868       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 869       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 870       unsigned int got_offset = got->add_constant(0);
 871       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 872                           got_offset, 0);
 873       got->add_constant(0);
 874       this->got_mod_index_offset_ = got_offset;
 875     }
 876   return this->got_mod_index_offset_;
 877 }
 878
 879 // Optimize the TLS relocation type based on what we know about the
 880 // symbol.  IS_FINAL is true if the final address of this symbol is
 881 // known at link time.
 882
 883 tls::Tls_optimization
 884 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 885 {
 886   // If we are generating a shared library, then we can't do anything
 887   // in the linker.
 888   if (parameters->options().shared())
 889     return tls::TLSOPT_NONE;
 890
 891   switch (r_type)
 892     {
 893     case elfcpp::R_X86_64_TLSGD:
 894     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 895     case elfcpp::R_X86_64_TLSDESC_CALL:
 896       // These are General-Dynamic which permits fully general TLS
 897       // access.  Since we know that we are generating an executable,
 898       // we can convert this to Initial-Exec.  If we also know that
 899       // this is a local symbol, we can further switch to Local-Exec.
 900       if (is_final)
 901         return tls::TLSOPT_TO_LE;
 902       return tls::TLSOPT_TO_IE;
 903
 904     case elfcpp::R_X86_64_TLSLD:
 905       // This is Local-Dynamic, which refers to a local symbol in the
 906       // dynamic TLS block.  Since we know that we generating an
 907       // executable, we can switch to Local-Exec.
 908       return tls::TLSOPT_TO_LE;
 909
 910     case elfcpp::R_X86_64_DTPOFF32:
 911     case elfcpp::R_X86_64_DTPOFF64:
 912       // Another Local-Dynamic reloc.
 913       return tls::TLSOPT_TO_LE;
 914
 915     case elfcpp::R_X86_64_GOTTPOFF:
 916       // These are Initial-Exec relocs which get the thread offset
 917       // from the GOT.  If we know that we are linking against the
 918       // local symbol, we can switch to Local-Exec, which links the
 919       // thread offset into the instruction.
 920       if (is_final)
 921         return tls::TLSOPT_TO_LE;
 922       return tls::TLSOPT_NONE;
 923
 924     case elfcpp::R_X86_64_TPOFF32:
 925       // When we already have Local-Exec, there is nothing further we
 926       // can do.
 927       return tls::TLSOPT_NONE;
 928
 929     default:
 930       gold_unreachable();
 931     }
 932 }
 933
 934 // Report an unsupported relocation against a local symbol.
 935
 936 void
 937 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 938                                              unsigned int r_type)
 939 {
 940   gold_error(_("%s: unsupported reloc %u against local symbol"),
 941              object->name().c_str(), r_type);
 942 }
 943
 944 // We are about to emit a dynamic relocation of type R_TYPE.  If the
 945 // dynamic linker does not support it, issue an error.  The GNU linker
 946 // only issues a non-PIC error for an allocated read-only section.
 947 // Here we know the section is allocated, but we don't know that it is
 948 // read-only.  But we check for all the relocation types which the
 949 // glibc dynamic linker supports, so it seems appropriate to issue an
 950 // error even if the section is not read-only.
 951
 952 void
 953 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
 954 {
 955   switch (r_type)
 956     {
 957       // These are the relocation types supported by glibc for x86_64.
 958     case elfcpp::R_X86_64_RELATIVE:
 959     case elfcpp::R_X86_64_GLOB_DAT:
 960     case elfcpp::R_X86_64_JUMP_SLOT:
 961     case elfcpp::R_X86_64_DTPMOD64:
 962     case elfcpp::R_X86_64_DTPOFF64:
 963     case elfcpp::R_X86_64_TPOFF64:
 964     case elfcpp::R_X86_64_64:
 965     case elfcpp::R_X86_64_32:
 966     case elfcpp::R_X86_64_PC32:
 967     case elfcpp::R_X86_64_COPY:
 968       return;
 969
 970     default:
 971       // This prevents us from issuing more than one error per reloc
 972       // section.  But we can still wind up issuing more than one
 973       // error per object file.
 974       if (this->issued_non_pic_error_)
 975         return;
 976       object->error(_("requires unsupported dynamic reloc; "
 977                       "recompile with -fPIC"));
 978       this->issued_non_pic_error_ = true;
 979       return;
 980
 981     case elfcpp::R_X86_64_NONE:
 982       gold_unreachable();
 983     }
 984 }
 985
 986 // Scan a relocation for a local symbol.
 987
 988 inline void
 989 Target_x86_64::Scan::local(const General_options&,
 990                            Symbol_table* symtab,
 991                            Layout* layout,
 992                            Target_x86_64* target,
 993                            Sized_relobj<64, false>* object,
 994                            unsigned int data_shndx,
 995                            Output_section* output_section,
 996                            const elfcpp::Rela<64, false>& reloc,
 997                            unsigned int r_type,
 998                            const elfcpp::Sym<64, false>& lsym)
 999 {
1000   switch (r_type)
1001     {
1002     case elfcpp::R_X86_64_NONE:
1003     case elfcpp::R_386_GNU_VTINHERIT:
1004     case elfcpp::R_386_GNU_VTENTRY:
1005       break;
1006
1007     case elfcpp::R_X86_64_64:
1008       // If building a shared library (or a position-independent
1009       // executable), we need to create a dynamic relocation for this
1010       // location.  The relocation applied at link time will apply the
1011       // link-time value, so we flag the location with an
1012       // R_X86_64_RELATIVE relocation so the dynamic loader can
1013       // relocate it easily.
1014       if (parameters->options().output_is_position_independent())
1015         {
1016           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1017           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1018           rela_dyn->add_local_relative(object, r_sym,
1019                                        elfcpp::R_X86_64_RELATIVE,
1020                                        output_section, data_shndx,
1021                                        reloc.get_r_offset(),
1022                                        reloc.get_r_addend());
1023         }
1024       break;
1025
1026     case elfcpp::R_X86_64_32:
1027     case elfcpp::R_X86_64_32S:
1028     case elfcpp::R_X86_64_16:
1029     case elfcpp::R_X86_64_8:
1030       // If building a shared library (or a position-independent
1031       // executable), we need to create a dynamic relocation for this
1032       // location.  We can't use an R_X86_64_RELATIVE relocation
1033       // because that is always a 64-bit relocation.
1034       if (parameters->options().output_is_position_independent())
1035         {
1036           this->check_non_pic(object, r_type);
1037
1038           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1039           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1040           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1041             rela_dyn->add_local(object, r_sym, r_type, output_section,
1042                                 data_shndx, reloc.get_r_offset(),
1043                                 reloc.get_r_addend());
1044           else
1045             {
1046               gold_assert(lsym.get_st_value() == 0);
1047               unsigned int shndx = lsym.get_st_shndx();
1048               bool is_ordinary;
1049               shndx = object->adjust_sym_shndx(r_sym, shndx,
1050                                                &is_ordinary);
1051               if (!is_ordinary)
1052                 object->error(_("section symbol %u has bad shndx %u"),
1053                               r_sym, shndx);
1054               else
1055                 rela_dyn->add_local_section(object, shndx,
1056                                             r_type, output_section,
1057                                             data_shndx, reloc.get_r_offset(),
1058                                             reloc.get_r_addend());
1059             }
1060         }
1061       break;
1062
1063     case elfcpp::R_X86_64_PC64:
1064     case elfcpp::R_X86_64_PC32:
1065     case elfcpp::R_X86_64_PC16:
1066     case elfcpp::R_X86_64_PC8:
1067       break;
1068
1069     case elfcpp::R_X86_64_PLT32:
1070       // Since we know this is a local symbol, we can handle this as a
1071       // PC32 reloc.
1072       break;
1073
1074     case elfcpp::R_X86_64_GOTPC32:
1075     case elfcpp::R_X86_64_GOTOFF64:
1076     case elfcpp::R_X86_64_GOTPC64:
1077     case elfcpp::R_X86_64_PLTOFF64:
1078       // We need a GOT section.
1079       target->got_section(symtab, layout);
1080       // For PLTOFF64, we'd normally want a PLT section, but since we
1081       // know this is a local symbol, no PLT is needed.
1082       break;
1083
1084     case elfcpp::R_X86_64_GOT64:
1085     case elfcpp::R_X86_64_GOT32:
1086     case elfcpp::R_X86_64_GOTPCREL64:
1087     case elfcpp::R_X86_64_GOTPCREL:
1088     case elfcpp::R_X86_64_GOTPLT64:
1089       {
1090         // The symbol requires a GOT entry.
1091         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1092         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1093         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1094           {
1095             // If we are generating a shared object, we need to add a
1096             // dynamic relocation for this symbol's GOT entry.
1097             if (parameters->options().output_is_position_independent())
1098               {
1099                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1100                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1101                 if (r_type != elfcpp::R_X86_64_GOT32)
1102                   rela_dyn->add_local_relative(
1103                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
1104                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1105                 else
1106                   {
1107                     this->check_non_pic(object, r_type);
1108
1109                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1110                     rela_dyn->add_local(
1111                         object, r_sym, r_type, got,
1112                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1113                   }
1114               }
1115           }
1116         // For GOTPLT64, we'd normally want a PLT section, but since
1117         // we know this is a local symbol, no PLT is needed.
1118       }
1119       break;
1120
1121     case elfcpp::R_X86_64_COPY:
1122     case elfcpp::R_X86_64_GLOB_DAT:
1123     case elfcpp::R_X86_64_JUMP_SLOT:
1124     case elfcpp::R_X86_64_RELATIVE:
1125       // These are outstanding tls relocs, which are unexpected when linking
1126     case elfcpp::R_X86_64_TPOFF64:
1127     case elfcpp::R_X86_64_DTPMOD64:
1128     case elfcpp::R_X86_64_TLSDESC:
1129       gold_error(_("%s: unexpected reloc %u in object file"),
1130                  object->name().c_str(), r_type);
1131       break;
1132
1133       // These are initial tls relocs, which are expected when linking
1134     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1135     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1136     case elfcpp::R_X86_64_TLSDESC_CALL:
1137     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1138     case elfcpp::R_X86_64_DTPOFF32:
1139     case elfcpp::R_X86_64_DTPOFF64:
1140     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1141     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1142       {
1143         bool output_is_shared = parameters->options().shared();
1144         const tls::Tls_optimization optimized_type
1145             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1146         switch (r_type)
1147           {
1148           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1149             if (optimized_type == tls::TLSOPT_NONE)
1150               {
1151                 // Create a pair of GOT entries for the module index and
1152                 // dtv-relative offset.
1153                 Output_data_got<64, false>* got
1154                     = target->got_section(symtab, layout);
1155                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1156                 unsigned int shndx = lsym.get_st_shndx();
1157                 bool is_ordinary;
1158                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1159                 if (!is_ordinary)
1160                   object->error(_("local symbol %u has bad shndx %u"),
1161                               r_sym, shndx);
1162                 else
1163                   got->add_local_pair_with_rela(object, r_sym,
1164                                                 shndx,
1165                                                 GOT_TYPE_TLS_PAIR,
1166                                                 target->rela_dyn_section(layout),
1167                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1168               }
1169             else if (optimized_type != tls::TLSOPT_TO_LE)
1170               unsupported_reloc_local(object, r_type);
1171             break;
1172
1173           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1174             target->define_tls_base_symbol(symtab, layout);
1175             if (optimized_type == tls::TLSOPT_NONE)
1176               {
1177                 // Create reserved PLT and GOT entries for the resolver.
1178                 target->reserve_tlsdesc_entries(symtab, layout);
1179
1180                 // Generate a double GOT entry with an R_X86_64_TLSDESC reloc.
1181                 Output_data_got<64, false>* got
1182                     = target->got_section(symtab, layout);
1183                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1184                 unsigned int shndx = lsym.get_st_shndx();
1185                 bool is_ordinary;
1186                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1187                 if (!is_ordinary)
1188                   object->error(_("local symbol %u has bad shndx %u"),
1189                               r_sym, shndx);
1190                 else
1191                   got->add_local_pair_with_rela(object, r_sym,
1192                                                 shndx,
1193                                                 GOT_TYPE_TLS_DESC,
1194                                                 target->rela_dyn_section(layout),
1195                                                 elfcpp::R_X86_64_TLSDESC, 0);
1196               }
1197             else if (optimized_type != tls::TLSOPT_TO_LE)
1198               unsupported_reloc_local(object, r_type);
1199             break;
1200
1201           case elfcpp::R_X86_64_TLSDESC_CALL:
1202             break;
1203
1204           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1205             if (optimized_type == tls::TLSOPT_NONE)
1206               {
1207                 // Create a GOT entry for the module index.
1208                 target->got_mod_index_entry(symtab, layout, object);
1209               }
1210             else if (optimized_type != tls::TLSOPT_TO_LE)
1211               unsupported_reloc_local(object, r_type);
1212             break;
1213
1214           case elfcpp::R_X86_64_DTPOFF32:
1215           case elfcpp::R_X86_64_DTPOFF64:
1216             break;
1217
1218           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1219             layout->set_has_static_tls();
1220             if (optimized_type == tls::TLSOPT_NONE)
1221               {
1222                 // Create a GOT entry for the tp-relative offset.
1223                 Output_data_got<64, false>* got
1224                     = target->got_section(symtab, layout);
1225                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1226                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1227                                          target->rela_dyn_section(layout),
1228                                          elfcpp::R_X86_64_TPOFF64);
1229               }
1230             else if (optimized_type != tls::TLSOPT_TO_LE)
1231               unsupported_reloc_local(object, r_type);
1232             break;
1233
1234           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1235             layout->set_has_static_tls();
1236             if (output_is_shared)
1237               unsupported_reloc_local(object, r_type);
1238             break;
1239
1240           default:
1241             gold_unreachable();
1242           }
1243       }
1244       break;
1245
1246     case elfcpp::R_X86_64_SIZE32:
1247     case elfcpp::R_X86_64_SIZE64:
1248     default:
1249       gold_error(_("%s: unsupported reloc %u against local symbol"),
1250                  object->name().c_str(), r_type);
1251       break;
1252     }
1253 }
1254
1255
1256 // Report an unsupported relocation against a global symbol.
1257
1258 void
1259 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1260                                               unsigned int r_type,
1261                                               Symbol* gsym)
1262 {
1263   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1264              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1265 }
1266
1267 // Scan a relocation for a global symbol.
1268
1269 inline void
1270 Target_x86_64::Scan::global(const General_options&,
1271                             Symbol_table* symtab,
1272                             Layout* layout,
1273                             Target_x86_64* target,
1274                             Sized_relobj<64, false>* object,
1275                             unsigned int data_shndx,
1276                             Output_section* output_section,
1277                             const elfcpp::Rela<64, false>& reloc,
1278                             unsigned int r_type,
1279                             Symbol* gsym)
1280 {
1281   switch (r_type)
1282     {
1283     case elfcpp::R_X86_64_NONE:
1284     case elfcpp::R_386_GNU_VTINHERIT:
1285     case elfcpp::R_386_GNU_VTENTRY:
1286       break;
1287
1288     case elfcpp::R_X86_64_64:
1289     case elfcpp::R_X86_64_32:
1290     case elfcpp::R_X86_64_32S:
1291     case elfcpp::R_X86_64_16:
1292     case elfcpp::R_X86_64_8:
1293       {
1294         // Make a PLT entry if necessary.
1295         if (gsym->needs_plt_entry())
1296           {
1297             target->make_plt_entry(symtab, layout, gsym);
1298             // Since this is not a PC-relative relocation, we may be
1299             // taking the address of a function. In that case we need to
1300             // set the entry in the dynamic symbol table to the address of
1301             // the PLT entry.
1302             if (gsym->is_from_dynobj() && !parameters->options().shared())
1303               gsym->set_needs_dynsym_value();
1304           }
1305         // Make a dynamic relocation if necessary.
1306         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1307           {
1308             if (target->may_need_copy_reloc(gsym))
1309               {
1310                 target->copy_reloc(symtab, layout, object,
1311                                    data_shndx, output_section, gsym, reloc);
1312               }
1313             else if (r_type == elfcpp::R_X86_64_64
1314                      && gsym->can_use_relative_reloc(false))
1315               {
1316                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1317                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1318                                               output_section, object,
1319                                               data_shndx, reloc.get_r_offset(),
1320                                               reloc.get_r_addend());
1321               }
1322             else
1323               {
1324                 this->check_non_pic(object, r_type);
1325                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1326                 rela_dyn->add_global(gsym, r_type, output_section, object,
1327                                      data_shndx, reloc.get_r_offset(),
1328                                      reloc.get_r_addend());
1329               }
1330           }
1331       }
1332       break;
1333
1334     case elfcpp::R_X86_64_PC64:
1335     case elfcpp::R_X86_64_PC32:
1336     case elfcpp::R_X86_64_PC16:
1337     case elfcpp::R_X86_64_PC8:
1338       {
1339         // Make a PLT entry if necessary.
1340         if (gsym->needs_plt_entry())
1341           target->make_plt_entry(symtab, layout, gsym);
1342         // Make a dynamic relocation if necessary.
1343         int flags = Symbol::NON_PIC_REF;
1344         if (gsym->type() == elfcpp::STT_FUNC)
1345           flags |= Symbol::FUNCTION_CALL;
1346         if (gsym->needs_dynamic_reloc(flags))
1347           {
1348             if (target->may_need_copy_reloc(gsym))
1349               {
1350                 target->copy_reloc(symtab, layout, object,
1351                                    data_shndx, output_section, gsym, reloc);
1352               }
1353             else
1354               {
1355                 this->check_non_pic(object, r_type);
1356                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1357                 rela_dyn->add_global(gsym, r_type, output_section, object,
1358                                      data_shndx, reloc.get_r_offset(),
1359                                      reloc.get_r_addend());
1360               }
1361           }
1362       }
1363       break;
1364
1365     case elfcpp::R_X86_64_GOT64:
1366     case elfcpp::R_X86_64_GOT32:
1367     case elfcpp::R_X86_64_GOTPCREL64:
1368     case elfcpp::R_X86_64_GOTPCREL:
1369     case elfcpp::R_X86_64_GOTPLT64:
1370       {
1371         // The symbol requires a GOT entry.
1372         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1373         if (gsym->final_value_is_known())
1374           got->add_global(gsym, GOT_TYPE_STANDARD);
1375         else
1376           {
1377             // If this symbol is not fully resolved, we need to add a
1378             // dynamic relocation for it.
1379             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1380             if (gsym->is_from_dynobj()
1381                 || gsym->is_undefined()
1382                 || gsym->is_preemptible())
1383               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1384                                         elfcpp::R_X86_64_GLOB_DAT);
1385             else
1386               {
1387                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1388                   rela_dyn->add_global_relative(
1389                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1390                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1391               }
1392           }
1393         // For GOTPLT64, we also need a PLT entry (but only if the
1394         // symbol is not fully resolved).
1395         if (r_type == elfcpp::R_X86_64_GOTPLT64
1396             && !gsym->final_value_is_known())
1397           target->make_plt_entry(symtab, layout, gsym);
1398       }
1399       break;
1400
1401     case elfcpp::R_X86_64_PLT32:
1402       // If the symbol is fully resolved, this is just a PC32 reloc.
1403       // Otherwise we need a PLT entry.
1404       if (gsym->final_value_is_known())
1405         break;
1406       // If building a shared library, we can also skip the PLT entry
1407       // if the symbol is defined in the output file and is protected
1408       // or hidden.
1409       if (gsym->is_defined()
1410           && !gsym->is_from_dynobj()
1411           && !gsym->is_preemptible())
1412         break;
1413       target->make_plt_entry(symtab, layout, gsym);
1414       break;
1415
1416     case elfcpp::R_X86_64_GOTPC32:
1417     case elfcpp::R_X86_64_GOTOFF64:
1418     case elfcpp::R_X86_64_GOTPC64:
1419     case elfcpp::R_X86_64_PLTOFF64:
1420       // We need a GOT section.
1421       target->got_section(symtab, layout);
1422       // For PLTOFF64, we also need a PLT entry (but only if the
1423       // symbol is not fully resolved).
1424       if (r_type == elfcpp::R_X86_64_PLTOFF64
1425           && !gsym->final_value_is_known())
1426         target->make_plt_entry(symtab, layout, gsym);
1427       break;
1428
1429     case elfcpp::R_X86_64_COPY:
1430     case elfcpp::R_X86_64_GLOB_DAT:
1431     case elfcpp::R_X86_64_JUMP_SLOT:
1432     case elfcpp::R_X86_64_RELATIVE:
1433       // These are outstanding tls relocs, which are unexpected when linking
1434     case elfcpp::R_X86_64_TPOFF64:
1435     case elfcpp::R_X86_64_DTPMOD64:
1436     case elfcpp::R_X86_64_TLSDESC:
1437       gold_error(_("%s: unexpected reloc %u in object file"),
1438                  object->name().c_str(), r_type);
1439       break;
1440
1441       // These are initial tls relocs, which are expected for global()
1442     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1443     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1444     case elfcpp::R_X86_64_TLSDESC_CALL:
1445     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1446     case elfcpp::R_X86_64_DTPOFF32:
1447     case elfcpp::R_X86_64_DTPOFF64:
1448     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1449     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1450       {
1451         const bool is_final = gsym->final_value_is_known();
1452         const tls::Tls_optimization optimized_type
1453             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1454         switch (r_type)
1455           {
1456           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1457             if (optimized_type == tls::TLSOPT_NONE)
1458               {
1459                 // Create a pair of GOT entries for the module index and
1460                 // dtv-relative offset.
1461                 Output_data_got<64, false>* got
1462                     = target->got_section(symtab, layout);
1463                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1464                                                target->rela_dyn_section(layout),
1465                                                elfcpp::R_X86_64_DTPMOD64,
1466                                                elfcpp::R_X86_64_DTPOFF64);
1467               }
1468             else if (optimized_type == tls::TLSOPT_TO_IE)
1469               {
1470                 // Create a GOT entry for the tp-relative offset.
1471                 Output_data_got<64, false>* got
1472                     = target->got_section(symtab, layout);
1473                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1474                                           target->rela_dyn_section(layout),
1475                                           elfcpp::R_X86_64_TPOFF64);
1476               }
1477             else if (optimized_type != tls::TLSOPT_TO_LE)
1478               unsupported_reloc_global(object, r_type, gsym);
1479             break;
1480
1481           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1482             target->define_tls_base_symbol(symtab, layout);
1483             if (optimized_type == tls::TLSOPT_NONE)
1484               {
1485                 // Create reserved PLT and GOT entries for the resolver.
1486                 target->reserve_tlsdesc_entries(symtab, layout);
1487
1488                 // Create a double GOT entry with an R_X86_64_TLSDESC reloc.
1489                 Output_data_got<64, false>* got
1490                     = target->got_section(symtab, layout);
1491                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC,
1492                                                target->rela_dyn_section(layout),
1493                                                elfcpp::R_X86_64_TLSDESC, 0);
1494               }
1495             else if (optimized_type == tls::TLSOPT_TO_IE)
1496               {
1497                 // Create a GOT entry for the tp-relative offset.
1498                 Output_data_got<64, false>* got
1499                     = target->got_section(symtab, layout);
1500                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1501                                           target->rela_dyn_section(layout),
1502                                           elfcpp::R_X86_64_TPOFF64);
1503               }
1504             else if (optimized_type != tls::TLSOPT_TO_LE)
1505               unsupported_reloc_global(object, r_type, gsym);
1506             break;
1507
1508           case elfcpp::R_X86_64_TLSDESC_CALL:
1509             break;
1510
1511           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1512             if (optimized_type == tls::TLSOPT_NONE)
1513               {
1514                 // Create a GOT entry for the module index.
1515                 target->got_mod_index_entry(symtab, layout, object);
1516               }
1517             else if (optimized_type != tls::TLSOPT_TO_LE)
1518               unsupported_reloc_global(object, r_type, gsym);
1519             break;
1520
1521           case elfcpp::R_X86_64_DTPOFF32:
1522           case elfcpp::R_X86_64_DTPOFF64:
1523             break;
1524
1525           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1526             layout->set_has_static_tls();
1527             if (optimized_type == tls::TLSOPT_NONE)
1528               {
1529                 // Create a GOT entry for the tp-relative offset.
1530                 Output_data_got<64, false>* got
1531                     = target->got_section(symtab, layout);
1532                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1533                                           target->rela_dyn_section(layout),
1534                                           elfcpp::R_X86_64_TPOFF64);
1535               }
1536             else if (optimized_type != tls::TLSOPT_TO_LE)
1537               unsupported_reloc_global(object, r_type, gsym);
1538             break;
1539
1540           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1541             layout->set_has_static_tls();
1542             if (parameters->options().shared())
1543               unsupported_reloc_local(object, r_type);
1544             break;
1545
1546           default:
1547             gold_unreachable();
1548           }
1549       }
1550       break;
1551
1552     case elfcpp::R_X86_64_SIZE32:
1553     case elfcpp::R_X86_64_SIZE64:
1554     default:
1555       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1556                  object->name().c_str(), r_type,
1557                  gsym->demangled_name().c_str());
1558       break;
1559     }
1560 }
1561
1562 void
1563 Target_x86_64::gc_process_relocs(const General_options& options,
1564                                  Symbol_table* symtab,
1565                                  Layout* layout,
1566                                  Sized_relobj<64, false>* object,
1567                                  unsigned int data_shndx,
1568                                  unsigned int sh_type,
1569                                  const unsigned char* prelocs,
1570                                  size_t reloc_count,
1571                                  Output_section* output_section,
1572                                  bool needs_special_offset_handling,
1573                                  size_t local_symbol_count,
1574                                  const unsigned char* plocal_symbols)
1575 {
1576
1577   if (sh_type == elfcpp::SHT_REL)
1578     {
1579       return;
1580     }
1581
1582    gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1583                            Target_x86_64::Scan>(
1584     options,
1585     symtab,
1586     layout,
1587     this,
1588     object,
1589     data_shndx,
1590     prelocs,
1591     reloc_count,
1592     output_section,
1593     needs_special_offset_handling,
1594     local_symbol_count,
1595     plocal_symbols);
1596
1597 }
1598 // Scan relocations for a section.
1599
1600 void
1601 Target_x86_64::scan_relocs(const General_options& options,
1602                            Symbol_table* symtab,
1603                            Layout* layout,
1604                            Sized_relobj<64, false>* object,
1605                            unsigned int data_shndx,
1606                            unsigned int sh_type,
1607                            const unsigned char* prelocs,
1608                            size_t reloc_count,
1609                            Output_section* output_section,
1610                            bool needs_special_offset_handling,
1611                            size_t local_symbol_count,
1612                            const unsigned char* plocal_symbols)
1613 {
1614   if (sh_type == elfcpp::SHT_REL)
1615     {
1616       gold_error(_("%s: unsupported REL reloc section"),
1617                  object->name().c_str());
1618       return;
1619     }
1620
1621   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1622       Target_x86_64::Scan>(
1623     options,
1624     symtab,
1625     layout,
1626     this,
1627     object,
1628     data_shndx,
1629     prelocs,
1630     reloc_count,
1631     output_section,
1632     needs_special_offset_handling,
1633     local_symbol_count,
1634     plocal_symbols);
1635 }
1636
1637 // Finalize the sections.
1638
1639 void
1640 Target_x86_64::do_finalize_sections(Layout* layout)
1641 {
1642   // Fill in some more dynamic tags.
1643   Output_data_dynamic* const odyn = layout->dynamic_data();
1644   if (odyn != NULL)
1645     {
1646       if (this->got_plt_ != NULL)
1647         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1648
1649       if (this->plt_ != NULL)
1650         {
1651           const Output_data* od = this->plt_->rel_plt();
1652           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1653           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1654           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1655           if (this->plt_->has_tlsdesc_entry())
1656             {
1657               unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
1658               unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
1659               this->got_->finalize_data_size();
1660               odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
1661                                             this->plt_, plt_offset);
1662               odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
1663                                             this->got_, got_offset);
1664             }
1665         }
1666
1667       if (this->rela_dyn_ != NULL)
1668         {
1669           const Output_data* od = this->rela_dyn_;
1670           odyn->add_section_address(elfcpp::DT_RELA, od);
1671           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1672           odyn->add_constant(elfcpp::DT_RELAENT,
1673                              elfcpp::Elf_sizes<64>::rela_size);
1674         }
1675
1676       if (!parameters->options().shared())
1677         {
1678           // The value of the DT_DEBUG tag is filled in by the dynamic
1679           // linker at run time, and used by the debugger.
1680           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1681         }
1682     }
1683
1684   // Emit any relocs we saved in an attempt to avoid generating COPY
1685   // relocs.
1686   if (this->copy_relocs_.any_saved_relocs())
1687     this->copy_relocs_.emit(this->rela_dyn_section(layout));
1688 }
1689
1690 // Perform a relocation.
1691
1692 inline bool
1693 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1694                                   Target_x86_64* target,
1695                                   Output_section*,
1696                                   size_t relnum,
1697                                   const elfcpp::Rela<64, false>& rela,
1698                                   unsigned int r_type,
1699                                   const Sized_symbol<64>* gsym,
1700                                   const Symbol_value<64>* psymval,
1701                                   unsigned char* view,
1702                                   elfcpp::Elf_types<64>::Elf_Addr address,
1703                                   section_size_type view_size)
1704 {
1705   if (this->skip_call_tls_get_addr_)
1706     {
1707       if ((r_type != elfcpp::R_X86_64_PLT32
1708            && r_type != elfcpp::R_X86_64_PC32)
1709           || gsym == NULL
1710           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1711         {
1712           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1713                                  _("missing expected TLS relocation"));
1714         }
1715       else
1716         {
1717           this->skip_call_tls_get_addr_ = false;
1718           return false;
1719         }
1720     }
1721
1722   // Pick the value to use for symbols defined in shared objects.
1723   Symbol_value<64> symval;
1724   if (gsym != NULL
1725       && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
1726                               || r_type == elfcpp::R_X86_64_PC32
1727                               || r_type == elfcpp::R_X86_64_PC16
1728                               || r_type == elfcpp::R_X86_64_PC8))
1729     {
1730       symval.set_output_value(target->plt_section()->address()
1731                               + gsym->plt_offset());
1732       psymval = &symval;
1733     }
1734
1735   const Sized_relobj<64, false>* object = relinfo->object;
1736   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1737
1738   // Get the GOT offset if needed.
1739   // The GOT pointer points to the end of the GOT section.
1740   // We need to subtract the size of the GOT section to get
1741   // the actual offset to use in the relocation.
1742   bool have_got_offset = false;
1743   unsigned int got_offset = 0;
1744   switch (r_type)
1745     {
1746     case elfcpp::R_X86_64_GOT32:
1747     case elfcpp::R_X86_64_GOT64:
1748     case elfcpp::R_X86_64_GOTPLT64:
1749     case elfcpp::R_X86_64_GOTPCREL:
1750     case elfcpp::R_X86_64_GOTPCREL64:
1751       if (gsym != NULL)
1752         {
1753           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1754           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1755         }
1756       else
1757         {
1758           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1759           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1760           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1761                         - target->got_size());
1762         }
1763       have_got_offset = true;
1764       break;
1765
1766     default:
1767       break;
1768     }
1769
1770   switch (r_type)
1771     {
1772     case elfcpp::R_X86_64_NONE:
1773     case elfcpp::R_386_GNU_VTINHERIT:
1774     case elfcpp::R_386_GNU_VTENTRY:
1775       break;
1776
1777     case elfcpp::R_X86_64_64:
1778       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1779       break;
1780
1781     case elfcpp::R_X86_64_PC64:
1782       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1783                                               address);
1784       break;
1785
1786     case elfcpp::R_X86_64_32:
1787       // FIXME: we need to verify that value + addend fits into 32 bits:
1788       //    uint64_t x = value + addend;
1789       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1790       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1791       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1792       break;
1793
1794     case elfcpp::R_X86_64_32S:
1795       // FIXME: we need to verify that value + addend fits into 32 bits:
1796       //    int64_t x = value + addend;   // note this quantity is signed!
1797       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1798       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1799       break;
1800
1801     case elfcpp::R_X86_64_PC32:
1802       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1803                                               address);
1804       break;
1805
1806     case elfcpp::R_X86_64_16:
1807       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1808       break;
1809
1810     case elfcpp::R_X86_64_PC16:
1811       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1812                                               address);
1813       break;
1814
1815     case elfcpp::R_X86_64_8:
1816       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1817       break;
1818
1819     case elfcpp::R_X86_64_PC8:
1820       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1821                                              address);
1822       break;
1823
1824     case elfcpp::R_X86_64_PLT32:
1825       gold_assert(gsym == NULL
1826                   || gsym->has_plt_offset()
1827                   || gsym->final_value_is_known()
1828                   || (gsym->is_defined()
1829                       && !gsym->is_from_dynobj()
1830                       && !gsym->is_preemptible()));
1831       // Note: while this code looks the same as for R_X86_64_PC32, it
1832       // behaves differently because psymval was set to point to
1833       // the PLT entry, rather than the symbol, in Scan::global().
1834       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1835                                               address);
1836       break;
1837
1838     case elfcpp::R_X86_64_PLTOFF64:
1839       {
1840         gold_assert(gsym);
1841         gold_assert(gsym->has_plt_offset()
1842                     || gsym->final_value_is_known());
1843         elfcpp::Elf_types<64>::Elf_Addr got_address;
1844         got_address = target->got_section(NULL, NULL)->address();
1845         Relocate_functions<64, false>::rela64(view, object, psymval,
1846                                               addend - got_address);
1847       }
1848
1849     case elfcpp::R_X86_64_GOT32:
1850       gold_assert(have_got_offset);
1851       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1852       break;
1853
1854     case elfcpp::R_X86_64_GOTPC32:
1855       {
1856         gold_assert(gsym);
1857         elfcpp::Elf_types<64>::Elf_Addr value;
1858         value = target->got_plt_section()->address();
1859         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1860       }
1861       break;
1862
1863     case elfcpp::R_X86_64_GOT64:
1864       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1865       // Since we always add a PLT entry, this is equivalent.
1866     case elfcpp::R_X86_64_GOTPLT64:
1867       gold_assert(have_got_offset);
1868       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1869       break;
1870
1871     case elfcpp::R_X86_64_GOTPC64:
1872       {
1873         gold_assert(gsym);
1874         elfcpp::Elf_types<64>::Elf_Addr value;
1875         value = target->got_plt_section()->address();
1876         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1877       }
1878       break;
1879
1880     case elfcpp::R_X86_64_GOTOFF64:
1881       {
1882         elfcpp::Elf_types<64>::Elf_Addr value;
1883         value = (psymval->value(object, 0)
1884                  - target->got_plt_section()->address());
1885         Relocate_functions<64, false>::rela64(view, value, addend);
1886       }
1887       break;
1888
1889     case elfcpp::R_X86_64_GOTPCREL:
1890       {
1891         gold_assert(have_got_offset);
1892         elfcpp::Elf_types<64>::Elf_Addr value;
1893         value = target->got_plt_section()->address() + got_offset;
1894         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1895       }
1896       break;
1897
1898     case elfcpp::R_X86_64_GOTPCREL64:
1899       {
1900         gold_assert(have_got_offset);
1901         elfcpp::Elf_types<64>::Elf_Addr value;
1902         value = target->got_plt_section()->address() + got_offset;
1903         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1904       }
1905       break;
1906
1907     case elfcpp::R_X86_64_COPY:
1908     case elfcpp::R_X86_64_GLOB_DAT:
1909     case elfcpp::R_X86_64_JUMP_SLOT:
1910     case elfcpp::R_X86_64_RELATIVE:
1911       // These are outstanding tls relocs, which are unexpected when linking
1912     case elfcpp::R_X86_64_TPOFF64:
1913     case elfcpp::R_X86_64_DTPMOD64:
1914     case elfcpp::R_X86_64_TLSDESC:
1915       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1916                              _("unexpected reloc %u in object file"),
1917                              r_type);
1918       break;
1919
1920       // These are initial tls relocs, which are expected when linking
1921     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1922     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1923     case elfcpp::R_X86_64_TLSDESC_CALL:
1924     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1925     case elfcpp::R_X86_64_DTPOFF32:
1926     case elfcpp::R_X86_64_DTPOFF64:
1927     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1928     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1929       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1930                          view, address, view_size);
1931       break;
1932
1933     case elfcpp::R_X86_64_SIZE32:
1934     case elfcpp::R_X86_64_SIZE64:
1935     default:
1936       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1937                              _("unsupported reloc %u"),
1938                              r_type);
1939       break;
1940     }
1941
1942   return true;
1943 }
1944
1945 // Perform a TLS relocation.
1946
1947 inline void
1948 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1949                                       Target_x86_64* target,
1950                                       size_t relnum,
1951                                       const elfcpp::Rela<64, false>& rela,
1952                                       unsigned int r_type,
1953                                       const Sized_symbol<64>* gsym,
1954                                       const Symbol_value<64>* psymval,
1955                                       unsigned char* view,
1956                                       elfcpp::Elf_types<64>::Elf_Addr address,
1957                                       section_size_type view_size)
1958 {
1959   Output_segment* tls_segment = relinfo->layout->tls_segment();
1960
1961   const Sized_relobj<64, false>* object = relinfo->object;
1962   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1963
1964   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1965
1966   const bool is_final = (gsym == NULL
1967                          ? !parameters->options().output_is_position_independent()
1968                          : gsym->final_value_is_known());
1969   const tls::Tls_optimization optimized_type
1970       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1971   switch (r_type)
1972     {
1973     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1974       this->saw_tls_block_reloc_ = true;
1975       if (optimized_type == tls::TLSOPT_TO_LE)
1976         {
1977           gold_assert(tls_segment != NULL);
1978           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1979                              rela, r_type, value, view,
1980                              view_size);
1981           break;
1982         }
1983       else
1984         {
1985           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1986                                    ? GOT_TYPE_TLS_OFFSET
1987                                    : GOT_TYPE_TLS_PAIR);
1988           unsigned int got_offset;
1989           if (gsym != NULL)
1990             {
1991               gold_assert(gsym->has_got_offset(got_type));
1992               got_offset = gsym->got_offset(got_type) - target->got_size();
1993             }
1994           else
1995             {
1996               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1997               gold_assert(object->local_has_got_offset(r_sym, got_type));
1998               got_offset = (object->local_got_offset(r_sym, got_type)
1999                             - target->got_size());
2000             }
2001           if (optimized_type == tls::TLSOPT_TO_IE)
2002             {
2003               gold_assert(tls_segment != NULL);
2004               value = target->got_plt_section()->address() + got_offset;
2005               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2006                                  value, view, address, view_size);
2007               break;
2008             }
2009           else if (optimized_type == tls::TLSOPT_NONE)
2010             {
2011               // Relocate the field with the offset of the pair of GOT
2012               // entries.
2013               value = target->got_plt_section()->address() + got_offset;
2014               Relocate_functions<64, false>::pcrela32(view, value, addend,
2015                                                       address);
2016               break;
2017             }
2018         }
2019       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2020                              _("unsupported reloc %u"), r_type);
2021       break;
2022
2023     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2024     case elfcpp::R_X86_64_TLSDESC_CALL:
2025       this->saw_tls_block_reloc_ = true;
2026       if (optimized_type == tls::TLSOPT_TO_LE)
2027         {
2028           gold_assert(tls_segment != NULL);
2029           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2030                                   rela, r_type, value, view,
2031                                   view_size);
2032           break;
2033         }
2034       else
2035         {
2036           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2037                                    ? GOT_TYPE_TLS_OFFSET
2038                                    : GOT_TYPE_TLS_DESC);
2039           unsigned int got_offset;
2040           if (gsym != NULL)
2041             {
2042               gold_assert(gsym->has_got_offset(got_type));
2043               got_offset = gsym->got_offset(got_type) - target->got_size();
2044             }
2045           else
2046             {
2047               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2048               gold_assert(object->local_has_got_offset(r_sym, got_type));
2049               got_offset = (object->local_got_offset(r_sym, got_type)
2050                             - target->got_size());
2051             }
2052           if (optimized_type == tls::TLSOPT_TO_IE)
2053             {
2054               gold_assert(tls_segment != NULL);
2055               value = target->got_plt_section()->address() + got_offset;
2056               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2057                                       rela, r_type, value, view, address,
2058                                       view_size);
2059               break;
2060             }
2061           else if (optimized_type == tls::TLSOPT_NONE)
2062             {
2063               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2064                 {
2065                   // Relocate the field with the offset of the pair of GOT
2066                   // entries.
2067                   value = target->got_plt_section()->address() + got_offset;
2068                   Relocate_functions<64, false>::pcrela32(view, value, addend,
2069                                                           address);
2070                 }
2071               break;
2072             }
2073         }
2074       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2075                              _("unsupported reloc %u"), r_type);
2076       break;
2077
2078     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2079       this->saw_tls_block_reloc_ = true;
2080       if (optimized_type == tls::TLSOPT_TO_LE)
2081         {
2082           gold_assert(tls_segment != NULL);
2083           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2084                              value, view, view_size);
2085           break;
2086         }
2087       else if (optimized_type == tls::TLSOPT_NONE)
2088         {
2089           // Relocate the field with the offset of the GOT entry for
2090           // the module index.
2091           unsigned int got_offset;
2092           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2093                         - target->got_size());
2094           value = target->got_plt_section()->address() + got_offset;
2095           Relocate_functions<64, false>::pcrela32(view, value, addend,
2096                                                   address);
2097           break;
2098         }
2099       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2100                              _("unsupported reloc %u"), r_type);
2101       break;
2102
2103     case elfcpp::R_X86_64_DTPOFF32:
2104       gold_assert(tls_segment != NULL);
2105       if (optimized_type == tls::TLSOPT_TO_LE)
2106         {
2107           // This relocation type is used in debugging information.
2108           // In that case we need to not optimize the value.  If we
2109           // haven't seen a TLSLD reloc, then we assume we should not
2110           // optimize this reloc.
2111           if (this->saw_tls_block_reloc_)
2112             value -= tls_segment->memsz();
2113         }
2114       Relocate_functions<64, false>::rela32(view, value, addend);
2115       break;
2116
2117     case elfcpp::R_X86_64_DTPOFF64:
2118       gold_assert(tls_segment != NULL);
2119       if (optimized_type == tls::TLSOPT_TO_LE)
2120         {
2121           // See R_X86_64_DTPOFF32, just above, for why we test this.
2122           if (this->saw_tls_block_reloc_)
2123             value -= tls_segment->memsz();
2124         }
2125       Relocate_functions<64, false>::rela64(view, value, addend);
2126       break;
2127
2128     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2129       if (optimized_type == tls::TLSOPT_TO_LE)
2130         {
2131           gold_assert(tls_segment != NULL);
2132           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2133                                                 rela, r_type, value, view,
2134                                                 view_size);
2135           break;
2136         }
2137       else if (optimized_type == tls::TLSOPT_NONE)
2138         {
2139           // Relocate the field with the offset of the GOT entry for
2140           // the tp-relative offset of the symbol.
2141           unsigned int got_offset;
2142           if (gsym != NULL)
2143             {
2144               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2145               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2146                             - target->got_size());
2147             }
2148           else
2149             {
2150               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2151               gold_assert(object->local_has_got_offset(r_sym,
2152                                                        GOT_TYPE_TLS_OFFSET));
2153               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2154                             - target->got_size());
2155             }
2156           value = target->got_plt_section()->address() + got_offset;
2157           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2158           break;
2159         }
2160       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2161                              _("unsupported reloc type %u"),
2162                              r_type);
2163       break;
2164
2165     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2166       value -= tls_segment->memsz();
2167       Relocate_functions<64, false>::rela32(view, value, addend);
2168       break;
2169     }
2170 }
2171
2172 // Do a relocation in which we convert a TLS General-Dynamic to an
2173 // Initial-Exec.
2174
2175 inline void
2176 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2177                                       size_t relnum,
2178                                       Output_segment*,
2179                                       const elfcpp::Rela<64, false>& rela,
2180                                       unsigned int,
2181                                       elfcpp::Elf_types<64>::Elf_Addr value,
2182                                       unsigned char* view,
2183                                       elfcpp::Elf_types<64>::Elf_Addr address,
2184                                       section_size_type view_size)
2185 {
2186   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2187   // .word 0x6666; rex64; call __tls_get_addr
2188   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2189
2190   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2191   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2192
2193   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2194                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2195   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2196                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2197
2198   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2199
2200   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2201   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2202
2203   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2204   // We can skip it.
2205   this->skip_call_tls_get_addr_ = true;
2206 }
2207
2208 // Do a relocation in which we convert a TLS General-Dynamic to a
2209 // Local-Exec.
2210
2211 inline void
2212 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2213                                       size_t relnum,
2214                                       Output_segment* tls_segment,
2215                                       const elfcpp::Rela<64, false>& rela,
2216                                       unsigned int,
2217                                       elfcpp::Elf_types<64>::Elf_Addr value,
2218                                       unsigned char* view,
2219                                       section_size_type view_size)
2220 {
2221   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2222   // .word 0x6666; rex64; call __tls_get_addr
2223   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2224
2225   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2226   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2227
2228   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2229                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2230   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2231                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2232
2233   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2234
2235   value -= tls_segment->memsz();
2236   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2237
2238   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2239   // We can skip it.
2240   this->skip_call_tls_get_addr_ = true;
2241 }
2242
2243 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2244
2245 inline void
2246 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2247     const Relocate_info<64, false>* relinfo,
2248     size_t relnum,
2249     Output_segment*,
2250     const elfcpp::Rela<64, false>& rela,
2251     unsigned int r_type,
2252     elfcpp::Elf_types<64>::Elf_Addr value,
2253     unsigned char* view,
2254     elfcpp::Elf_types<64>::Elf_Addr address,
2255     section_size_type view_size)
2256 {
2257   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2258     {
2259       // leaq foo@tlsdesc(%rip), %rax
2260       // ==> movq foo@gottpoff(%rip), %rax
2261       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2262       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2263       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2264                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2265       view[-2] = 0x8b;
2266       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2267       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2268     }
2269   else
2270     {
2271       // call *foo@tlscall(%rax)
2272       // ==> nop; nop
2273       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2274       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2275       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2276                      view[0] == 0xff && view[1] == 0x10);
2277       view[0] = 0x66;
2278       view[1] = 0x90;
2279     }
2280 }
2281
2282 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2283
2284 inline void
2285 Target_x86_64::Relocate::tls_desc_gd_to_le(
2286     const Relocate_info<64, false>* relinfo,
2287     size_t relnum,
2288     Output_segment* tls_segment,
2289     const elfcpp::Rela<64, false>& rela,
2290     unsigned int r_type,
2291     elfcpp::Elf_types<64>::Elf_Addr value,
2292     unsigned char* view,
2293     section_size_type view_size)
2294 {
2295   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2296     {
2297       // leaq foo@tlsdesc(%rip), %rax
2298       // ==> movq foo@tpoff, %rax
2299       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2300       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2301       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2302                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2303       view[-2] = 0xc7;
2304       view[-1] = 0xc0;
2305       value -= tls_segment->memsz();
2306       Relocate_functions<64, false>::rela32(view, value, 0);
2307     }
2308   else
2309     {
2310       // call *foo@tlscall(%rax)
2311       // ==> nop; nop
2312       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2313       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2314       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2315                      view[0] == 0xff && view[1] == 0x10);
2316       view[0] = 0x66;
2317       view[1] = 0x90;
2318     }
2319 }
2320
2321 inline void
2322 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2323                                       size_t relnum,
2324                                       Output_segment*,
2325                                       const elfcpp::Rela<64, false>& rela,
2326                                       unsigned int,
2327                                       elfcpp::Elf_types<64>::Elf_Addr,
2328                                       unsigned char* view,
2329                                       section_size_type view_size)
2330 {
2331   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2332   // ... leq foo@dtpoff(%rax),%reg
2333   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2334
2335   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2336   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2337
2338   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2339                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2340
2341   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2342
2343   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2344
2345   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2346   // We can skip it.
2347   this->skip_call_tls_get_addr_ = true;
2348 }
2349
2350 // Do a relocation in which we convert a TLS Initial-Exec to a
2351 // Local-Exec.
2352
2353 inline void
2354 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2355                                       size_t relnum,
2356                                       Output_segment* tls_segment,
2357                                       const elfcpp::Rela<64, false>& rela,
2358                                       unsigned int,
2359                                       elfcpp::Elf_types<64>::Elf_Addr value,
2360                                       unsigned char* view,
2361                                       section_size_type view_size)
2362 {
2363   // We need to examine the opcodes to figure out which instruction we
2364   // are looking at.
2365
2366   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2367   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2368
2369   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2370   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2371
2372   unsigned char op1 = view[-3];
2373   unsigned char op2 = view[-2];
2374   unsigned char op3 = view[-1];
2375   unsigned char reg = op3 >> 3;
2376
2377   if (op2 == 0x8b)
2378     {
2379       // movq
2380       if (op1 == 0x4c)
2381         view[-3] = 0x49;
2382       view[-2] = 0xc7;
2383       view[-1] = 0xc0 | reg;
2384     }
2385   else if (reg == 4)
2386     {
2387       // Special handling for %rsp.
2388       if (op1 == 0x4c)
2389         view[-3] = 0x49;
2390       view[-2] = 0x81;
2391       view[-1] = 0xc0 | reg;
2392     }
2393   else
2394     {
2395       // addq
2396       if (op1 == 0x4c)
2397         view[-3] = 0x4d;
2398       view[-2] = 0x8d;
2399       view[-1] = 0x80 | reg | (reg << 3);
2400     }
2401
2402   value -= tls_segment->memsz();
2403   Relocate_functions<64, false>::rela32(view, value, 0);
2404 }
2405
2406 // Relocate section data.
2407
2408 void
2409 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
2410                                 unsigned int sh_type,
2411                                 const unsigned char* prelocs,
2412                                 size_t reloc_count,
2413                                 Output_section* output_section,
2414                                 bool needs_special_offset_handling,
2415                                 unsigned char* view,
2416                                 elfcpp::Elf_types<64>::Elf_Addr address,
2417                                 section_size_type view_size)
2418 {
2419   gold_assert(sh_type == elfcpp::SHT_RELA);
2420
2421   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2422                          Target_x86_64::Relocate>(
2423     relinfo,
2424     this,
2425     prelocs,
2426     reloc_count,
2427     output_section,
2428     needs_special_offset_handling,
2429     view,
2430     address,
2431     view_size);
2432 }
2433
2434 // Return the size of a relocation while scanning during a relocatable
2435 // link.
2436
2437 unsigned int
2438 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2439     unsigned int r_type,
2440     Relobj* object)
2441 {
2442   switch (r_type)
2443     {
2444     case elfcpp::R_X86_64_NONE:
2445     case elfcpp::R_386_GNU_VTINHERIT:
2446     case elfcpp::R_386_GNU_VTENTRY:
2447     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2448     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2449     case elfcpp::R_X86_64_TLSDESC_CALL:
2450     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2451     case elfcpp::R_X86_64_DTPOFF32:
2452     case elfcpp::R_X86_64_DTPOFF64:
2453     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2454     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2455       return 0;
2456
2457     case elfcpp::R_X86_64_64:
2458     case elfcpp::R_X86_64_PC64:
2459     case elfcpp::R_X86_64_GOTOFF64:
2460     case elfcpp::R_X86_64_GOTPC64:
2461     case elfcpp::R_X86_64_PLTOFF64:
2462     case elfcpp::R_X86_64_GOT64:
2463     case elfcpp::R_X86_64_GOTPCREL64:
2464     case elfcpp::R_X86_64_GOTPCREL:
2465     case elfcpp::R_X86_64_GOTPLT64:
2466       return 8;
2467
2468     case elfcpp::R_X86_64_32:
2469     case elfcpp::R_X86_64_32S:
2470     case elfcpp::R_X86_64_PC32:
2471     case elfcpp::R_X86_64_PLT32:
2472     case elfcpp::R_X86_64_GOTPC32:
2473     case elfcpp::R_X86_64_GOT32:
2474       return 4;
2475
2476     case elfcpp::R_X86_64_16:
2477     case elfcpp::R_X86_64_PC16:
2478       return 2;
2479
2480     case elfcpp::R_X86_64_8:
2481     case elfcpp::R_X86_64_PC8:
2482       return 1;
2483
2484     case elfcpp::R_X86_64_COPY:
2485     case elfcpp::R_X86_64_GLOB_DAT:
2486     case elfcpp::R_X86_64_JUMP_SLOT:
2487     case elfcpp::R_X86_64_RELATIVE:
2488       // These are outstanding tls relocs, which are unexpected when linking
2489     case elfcpp::R_X86_64_TPOFF64:
2490     case elfcpp::R_X86_64_DTPMOD64:
2491     case elfcpp::R_X86_64_TLSDESC:
2492       object->error(_("unexpected reloc %u in object file"), r_type);
2493       return 0;
2494
2495     case elfcpp::R_X86_64_SIZE32:
2496     case elfcpp::R_X86_64_SIZE64:
2497     default:
2498       object->error(_("unsupported reloc %u against local symbol"), r_type);
2499       return 0;
2500     }
2501 }
2502
2503 // Scan the relocs during a relocatable link.
2504
2505 void
2506 Target_x86_64::scan_relocatable_relocs(const General_options& options,
2507                                        Symbol_table* symtab,
2508                                        Layout* layout,
2509                                        Sized_relobj<64, false>* object,
2510                                        unsigned int data_shndx,
2511                                        unsigned int sh_type,
2512                                        const unsigned char* prelocs,
2513                                        size_t reloc_count,
2514                                        Output_section* output_section,
2515                                        bool needs_special_offset_handling,
2516                                        size_t local_symbol_count,
2517                                        const unsigned char* plocal_symbols,
2518                                        Relocatable_relocs* rr)
2519 {
2520   gold_assert(sh_type == elfcpp::SHT_RELA);
2521
2522   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2523     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2524
2525   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2526       Scan_relocatable_relocs>(
2527     options,
2528     symtab,
2529     layout,
2530     object,
2531     data_shndx,
2532     prelocs,
2533     reloc_count,
2534     output_section,
2535     needs_special_offset_handling,
2536     local_symbol_count,
2537     plocal_symbols,
2538     rr);
2539 }
2540
2541 // Relocate a section during a relocatable link.
2542
2543 void
2544 Target_x86_64::relocate_for_relocatable(
2545     const Relocate_info<64, false>* relinfo,
2546     unsigned int sh_type,
2547     const unsigned char* prelocs,
2548     size_t reloc_count,
2549     Output_section* output_section,
2550     off_t offset_in_output_section,
2551     const Relocatable_relocs* rr,
2552     unsigned char* view,
2553     elfcpp::Elf_types<64>::Elf_Addr view_address,
2554     section_size_type view_size,
2555     unsigned char* reloc_view,
2556     section_size_type reloc_view_size)
2557 {
2558   gold_assert(sh_type == elfcpp::SHT_RELA);
2559
2560   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2561     relinfo,
2562     prelocs,
2563     reloc_count,
2564     output_section,
2565     offset_in_output_section,
2566     rr,
2567     view,
2568     view_address,
2569     view_size,
2570     reloc_view,
2571     reloc_view_size);
2572 }
2573
2574 // Return the value to use for a dynamic which requires special
2575 // treatment.  This is how we support equality comparisons of function
2576 // pointers across shared library boundaries, as described in the
2577 // processor specific ABI supplement.
2578
2579 uint64_t
2580 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2581 {
2582   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2583   return this->plt_section()->address() + gsym->plt_offset();
2584 }
2585
2586 // Return a string used to fill a code section with nops to take up
2587 // the specified length.
2588
2589 std::string
2590 Target_x86_64::do_code_fill(section_size_type length) const
2591 {
2592   if (length >= 16)
2593     {
2594       // Build a jmpq instruction to skip over the bytes.
2595       unsigned char jmp[5];
2596       jmp[0] = 0xe9;
2597       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2598       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2599               + std::string(length - 5, '\0'));
2600     }
2601
2602   // Nop sequences of various lengths.
2603   const char nop1[1] = { 0x90 };                   // nop
2604   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2605   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2606   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2607   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2608                          0x00 };                   // leal 0(%esi,1),%esi
2609   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2610                          0x00, 0x00 };
2611   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2612                          0x00, 0x00, 0x00 };
2613   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2614                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2615   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2616                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2617                          0x00 };
2618   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2619                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2620                            0x00, 0x00 };
2621   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2622                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2623                            0x00, 0x00, 0x00 };
2624   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2625                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2626                            0x00, 0x00, 0x00, 0x00 };
2627   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2628                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2629                            0x27, 0x00, 0x00, 0x00,
2630                            0x00 };
2631   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2632                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2633                            0xbc, 0x27, 0x00, 0x00,
2634                            0x00, 0x00 };
2635   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2636                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2637                            0x90, 0x90, 0x90, 0x90,
2638                            0x90, 0x90, 0x90 };
2639
2640   const char* nops[16] = {
2641     NULL,
2642     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2643     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2644   };
2645
2646   return std::string(nops[length], length);
2647 }
2648
2649 // The selector for x86_64 object files.
2650
2651 class Target_selector_x86_64 : public Target_selector
2652 {
2653 public:
2654   Target_selector_x86_64()
2655     : Target_selector(elfcpp::EM_X86_64, 64, false, "elf64-x86-64")
2656   { }
2657
2658   Target*
2659   do_instantiate_target()
2660   { return new Target_x86_64(); }
2661 };
2662
2663 Target_selector_x86_64 target_selector_x86_64;
2664
2665 } // End anonymous namespace.