gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 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 #include "freebsd.h"
  41 #include "gc.h"
  42 #include "icf.h"
  43
  44 namespace
  45 {
  46
  47 using namespace gold;
  48
  49 class Output_data_plt_x86_64;
  50
  51 // The x86_64 target class.
  52 // See the ABI at
  53 //   http://www.x86-64.org/documentation/abi.pdf
  54 // TLS info comes from
  55 //   http://people.redhat.com/drepper/tls.pdf
  56 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  57
  58 class Target_x86_64 : public Target_freebsd<64, false>
  59 {
  60  public:
  61   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
  62   // uses only Elf64_Rela relocation entries with explicit addends."
  63   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  64
  65   Target_x86_64()
  66     : Target_freebsd<64, false>(&x86_64_info),
  67       got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL),
  68       global_offset_table_(NULL), rela_dyn_(NULL),
  69       copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
  70       got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
  71       tls_base_symbol_defined_(false)
  72   { }
  73
  74   // This function should be defined in targets that can use relocation
  75   // types to determine (implemented in local_reloc_may_be_function_pointer
  76   // and global_reloc_may_be_function_pointer)
  77   // if a function's pointer is taken.  ICF uses this in safe mode to only
  78   // fold those functions whose pointer is defintely not taken.  For x86_64
  79   // pie binaries, safe ICF cannot be done by looking at relocation types.
  80   inline bool
  81   can_check_for_function_pointers() const
  82   { return !parameters->options().pie(); }
  83
  84   // Hook for a new output section.
  85   void
  86   do_new_output_section(Output_section*) const;
  87
  88   // Scan the relocations to look for symbol adjustments.
  89   void
  90   gc_process_relocs(Symbol_table* symtab,
  91                     Layout* layout,
  92                     Sized_relobj<64, false>* object,
  93                     unsigned int data_shndx,
  94                     unsigned int sh_type,
  95                     const unsigned char* prelocs,
  96                     size_t reloc_count,
  97                     Output_section* output_section,
  98                     bool needs_special_offset_handling,
  99                     size_t local_symbol_count,
 100                     const unsigned char* plocal_symbols);
 101
 102   // Scan the relocations to look for symbol adjustments.
 103   void
 104   scan_relocs(Symbol_table* symtab,
 105               Layout* layout,
 106               Sized_relobj<64, false>* object,
 107               unsigned int data_shndx,
 108               unsigned int sh_type,
 109               const unsigned char* prelocs,
 110               size_t reloc_count,
 111               Output_section* output_section,
 112               bool needs_special_offset_handling,
 113               size_t local_symbol_count,
 114               const unsigned char* plocal_symbols);
 115
 116   // Finalize the sections.
 117   void
 118   do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
 119
 120   // Return the value to use for a dynamic which requires special
 121   // treatment.
 122   uint64_t
 123   do_dynsym_value(const Symbol*) const;
 124
 125   // Relocate a section.
 126   void
 127   relocate_section(const Relocate_info<64, false>*,
 128                    unsigned int sh_type,
 129                    const unsigned char* prelocs,
 130                    size_t reloc_count,
 131                    Output_section* output_section,
 132                    bool needs_special_offset_handling,
 133                    unsigned char* view,
 134                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 135                    section_size_type view_size,
 136                    const Reloc_symbol_changes*);
 137
 138   // Scan the relocs during a relocatable link.
 139   void
 140   scan_relocatable_relocs(Symbol_table* symtab,
 141                           Layout* layout,
 142                           Sized_relobj<64, false>* object,
 143                           unsigned int data_shndx,
 144                           unsigned int sh_type,
 145                           const unsigned char* prelocs,
 146                           size_t reloc_count,
 147                           Output_section* output_section,
 148                           bool needs_special_offset_handling,
 149                           size_t local_symbol_count,
 150                           const unsigned char* plocal_symbols,
 151                           Relocatable_relocs*);
 152
 153   // Relocate a section during a relocatable link.
 154   void
 155   relocate_for_relocatable(const Relocate_info<64, false>*,
 156                            unsigned int sh_type,
 157                            const unsigned char* prelocs,
 158                            size_t reloc_count,
 159                            Output_section* output_section,
 160                            off_t offset_in_output_section,
 161                            const Relocatable_relocs*,
 162                            unsigned char* view,
 163                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 164                            section_size_type view_size,
 165                            unsigned char* reloc_view,
 166                            section_size_type reloc_view_size);
 167
 168   // Return a string used to fill a code section with nops.
 169   std::string
 170   do_code_fill(section_size_type length) const;
 171
 172   // Return whether SYM is defined by the ABI.
 173   bool
 174   do_is_defined_by_abi(const Symbol* sym) const
 175   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 176
 177   // Return the symbol index to use for a target specific relocation.
 178   // The only target specific relocation is R_X86_64_TLSDESC for a
 179   // local symbol, which is an absolute reloc.
 180   unsigned int
 181   do_reloc_symbol_index(void*, unsigned int r_type) const
 182   {
 183     gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
 184     return 0;
 185   }
 186
 187   // Return the addend to use for a target specific relocation.
 188   uint64_t
 189   do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
 190
 191   // Adjust -fstack-split code which calls non-stack-split code.
 192   void
 193   do_calls_non_split(Relobj* object, unsigned int shndx,
 194                      section_offset_type fnoffset, section_size_type fnsize,
 195                      unsigned char* view, section_size_type view_size,
 196                      std::string* from, std::string* to) const;
 197
 198   // Return the size of the GOT section.
 199   section_size_type
 200   got_size() const
 201   {
 202     gold_assert(this->got_ != NULL);
 203     return this->got_->data_size();
 204   }
 205
 206   // Return the number of entries in the GOT.
 207   unsigned int
 208   got_entry_count() const
 209   {
 210     if (this->got_ == NULL)
 211       return 0;
 212     return this->got_size() / 8;
 213   }
 214
 215   // Return the number of entries in the PLT.
 216   unsigned int
 217   plt_entry_count() const;
 218
 219   // Return the offset of the first non-reserved PLT entry.
 220   unsigned int
 221   first_plt_entry_offset() const;
 222
 223   // Return the size of each PLT entry.
 224   unsigned int
 225   plt_entry_size() const;
 226
 227   // Add a new reloc argument, returning the index in the vector.
 228   size_t
 229   add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym)
 230   {
 231     this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
 232     return this->tlsdesc_reloc_info_.size() - 1;
 233   }
 234
 235  private:
 236   // The class which scans relocations.
 237   class Scan
 238   {
 239   public:
 240     Scan()
 241       : issued_non_pic_error_(false)
 242     { }
 243
 244     inline void
 245     local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 246           Sized_relobj<64, false>* object,
 247           unsigned int data_shndx,
 248           Output_section* output_section,
 249           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 250           const elfcpp::Sym<64, false>& lsym);
 251
 252     inline void
 253     global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 254            Sized_relobj<64, false>* object,
 255            unsigned int data_shndx,
 256            Output_section* output_section,
 257            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 258            Symbol* gsym);
 259
 260     inline bool
 261     local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 262                                         Target_x86_64* target,
 263                                         Sized_relobj<64, false>* object,
 264                                         unsigned int data_shndx,
 265                                         Output_section* output_section,
 266                                         const elfcpp::Rela<64, false>& reloc,
 267                                         unsigned int r_type,
 268                                         const elfcpp::Sym<64, false>& lsym);
 269
 270     inline bool
 271     global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 272                                          Target_x86_64* target,
 273                                          Sized_relobj<64, false>* object,
 274                                          unsigned int data_shndx,
 275                                          Output_section* output_section,
 276                                          const elfcpp::Rela<64, false>& reloc,
 277                                          unsigned int r_type,
 278                                          Symbol* gsym);
 279
 280   private:
 281     static void
 282     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 283
 284     static void
 285     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 286                              Symbol*);
 287
 288     void
 289     check_non_pic(Relobj*, unsigned int r_type);
 290
 291     inline bool
 292     possible_function_pointer_reloc(unsigned int r_type);
 293
 294     // Whether we have issued an error about a non-PIC compilation.
 295     bool issued_non_pic_error_;
 296   };
 297
 298   // The class which implements relocation.
 299   class Relocate
 300   {
 301    public:
 302     Relocate()
 303       : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
 304     { }
 305
 306     ~Relocate()
 307     {
 308       if (this->skip_call_tls_get_addr_)
 309         {
 310           // FIXME: This needs to specify the location somehow.
 311           gold_error(_("missing expected TLS relocation"));
 312         }
 313     }
 314
 315     // Do a relocation.  Return false if the caller should not issue
 316     // any warnings about this relocation.
 317     inline bool
 318     relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
 319              size_t relnum, const elfcpp::Rela<64, false>&,
 320              unsigned int r_type, const Sized_symbol<64>*,
 321              const Symbol_value<64>*,
 322              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 323              section_size_type);
 324
 325    private:
 326     // Do a TLS relocation.
 327     inline void
 328     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 329                  size_t relnum, const elfcpp::Rela<64, false>&,
 330                  unsigned int r_type, const Sized_symbol<64>*,
 331                  const Symbol_value<64>*,
 332                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 333                  section_size_type);
 334
 335     // Do a TLS General-Dynamic to Initial-Exec transition.
 336     inline void
 337     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 338                  Output_segment* tls_segment,
 339                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 340                  elfcpp::Elf_types<64>::Elf_Addr value,
 341                  unsigned char* view,
 342                  elfcpp::Elf_types<64>::Elf_Addr,
 343                  section_size_type view_size);
 344
 345     // Do a TLS General-Dynamic to Local-Exec transition.
 346     inline void
 347     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 348                  Output_segment* tls_segment,
 349                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 350                  elfcpp::Elf_types<64>::Elf_Addr value,
 351                  unsigned char* view,
 352                  section_size_type view_size);
 353
 354     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 355     inline void
 356     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 357                       Output_segment* tls_segment,
 358                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 359                       elfcpp::Elf_types<64>::Elf_Addr value,
 360                       unsigned char* view,
 361                       elfcpp::Elf_types<64>::Elf_Addr,
 362                       section_size_type view_size);
 363
 364     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 365     inline void
 366     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 367                       Output_segment* tls_segment,
 368                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 369                       elfcpp::Elf_types<64>::Elf_Addr value,
 370                       unsigned char* view,
 371                       section_size_type view_size);
 372
 373     // Do a TLS Local-Dynamic to Local-Exec transition.
 374     inline void
 375     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 376                  Output_segment* tls_segment,
 377                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 378                  elfcpp::Elf_types<64>::Elf_Addr value,
 379                  unsigned char* view,
 380                  section_size_type view_size);
 381
 382     // Do a TLS Initial-Exec to Local-Exec transition.
 383     static inline void
 384     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 385                  Output_segment* tls_segment,
 386                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 387                  elfcpp::Elf_types<64>::Elf_Addr value,
 388                  unsigned char* view,
 389                  section_size_type view_size);
 390
 391     // This is set if we should skip the next reloc, which should be a
 392     // PLT32 reloc against ___tls_get_addr.
 393     bool skip_call_tls_get_addr_;
 394
 395     // This is set if we see a relocation which could load the address
 396     // of the TLS block.  Whether we see such a relocation determines
 397     // how we handle the R_X86_64_DTPOFF32 relocation, which is used
 398     // in debugging sections.
 399     bool saw_tls_block_reloc_;
 400   };
 401
 402   // A class which returns the size required for a relocation type,
 403   // used while scanning relocs during a relocatable link.
 404   class Relocatable_size_for_reloc
 405   {
 406    public:
 407     unsigned int
 408     get_size_for_reloc(unsigned int, Relobj*);
 409   };
 410
 411   // Adjust TLS relocation type based on the options and whether this
 412   // is a local symbol.
 413   static tls::Tls_optimization
 414   optimize_tls_reloc(bool is_final, int r_type);
 415
 416   // Get the GOT section, creating it if necessary.
 417   Output_data_got<64, false>*
 418   got_section(Symbol_table*, Layout*);
 419
 420   // Get the GOT PLT section.
 421   Output_data_space*
 422   got_plt_section() const
 423   {
 424     gold_assert(this->got_plt_ != NULL);
 425     return this->got_plt_;
 426   }
 427
 428   // Get the GOT section for TLSDESC entries.
 429   Output_data_got<64, false>*
 430   got_tlsdesc_section() const
 431   {
 432     gold_assert(this->got_tlsdesc_ != NULL);
 433     return this->got_tlsdesc_;
 434   }
 435
 436   // Create the PLT section.
 437   void
 438   make_plt_section(Symbol_table* symtab, Layout* layout);
 439
 440   // Create a PLT entry for a global symbol.
 441   void
 442   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 443
 444   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 445   void
 446   define_tls_base_symbol(Symbol_table*, Layout*);
 447
 448   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 449   void
 450   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 451
 452   // Create a GOT entry for the TLS module index.
 453   unsigned int
 454   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 455                       Sized_relobj<64, false>* object);
 456
 457   // Get the PLT section.
 458   Output_data_plt_x86_64*
 459   plt_section() const
 460   {
 461     gold_assert(this->plt_ != NULL);
 462     return this->plt_;
 463   }
 464
 465   // Get the dynamic reloc section, creating it if necessary.
 466   Reloc_section*
 467   rela_dyn_section(Layout*);
 468
 469   // Get the section to use for TLSDESC relocations.
 470   Reloc_section*
 471   rela_tlsdesc_section(Layout*) const;
 472
 473   // Add a potential copy relocation.
 474   void
 475   copy_reloc(Symbol_table* symtab, Layout* layout,
 476              Sized_relobj<64, false>* object,
 477              unsigned int shndx, Output_section* output_section,
 478              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 479   {
 480     this->copy_relocs_.copy_reloc(symtab, layout,
 481                                   symtab->get_sized_symbol<64>(sym),
 482                                   object, shndx, output_section,
 483                                   reloc, this->rela_dyn_section(layout));
 484   }
 485
 486   // Information about this specific target which we pass to the
 487   // general Target structure.
 488   static const Target::Target_info x86_64_info;
 489
 490   // The types of GOT entries needed for this platform.
 491   // These values are exposed to the ABI in an incremental link.
 492   // Do not renumber existing values without changing the version
 493   // number of the .gnu_incremental_inputs section.
 494   enum Got_type
 495   {
 496     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 497     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 498     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 499     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 500   };
 501
 502   // This type is used as the argument to the target specific
 503   // relocation routines.  The only target specific reloc is
 504   // R_X86_64_TLSDESC against a local symbol.
 505   struct Tlsdesc_info
 506   {
 507     Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym)
 508       : object(a_object), r_sym(a_r_sym)
 509     { }
 510
 511     // The object in which the local symbol is defined.
 512     Sized_relobj<64, false>* object;
 513     // The local symbol index in the object.
 514     unsigned int r_sym;
 515   };
 516
 517   // The GOT section.
 518   Output_data_got<64, false>* got_;
 519   // The PLT section.
 520   Output_data_plt_x86_64* plt_;
 521   // The GOT PLT section.
 522   Output_data_space* got_plt_;
 523   // The GOT section for TLSDESC relocations.
 524   Output_data_got<64, false>* got_tlsdesc_;
 525   // The _GLOBAL_OFFSET_TABLE_ symbol.
 526   Symbol* global_offset_table_;
 527   // The dynamic reloc section.
 528   Reloc_section* rela_dyn_;
 529   // Relocs saved to avoid a COPY reloc.
 530   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 531   // Space for variables copied with a COPY reloc.
 532   Output_data_space* dynbss_;
 533   // Offset of the GOT entry for the TLS module index.
 534   unsigned int got_mod_index_offset_;
 535   // We handle R_X86_64_TLSDESC against a local symbol as a target
 536   // specific relocation.  Here we store the object and local symbol
 537   // index for the relocation.
 538   std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
 539   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 540   bool tls_base_symbol_defined_;
 541 };
 542
 543 const Target::Target_info Target_x86_64::x86_64_info =
 544 {
 545   64,                   // size
 546   false,                // is_big_endian
 547   elfcpp::EM_X86_64,    // machine_code
 548   false,                // has_make_symbol
 549   false,                // has_resolve
 550   true,                 // has_code_fill
 551   true,                 // is_default_stack_executable
 552   '\0',                 // wrap_char
 553   "/lib/ld64.so.1",     // program interpreter
 554   0x400000,             // default_text_segment_address
 555   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 556   0x1000,               // common_pagesize (overridable by -z common-page-size)
 557   elfcpp::SHN_UNDEF,    // small_common_shndx
 558   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 559   0,                    // small_common_section_flags
 560   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 561   NULL,                 // attributes_section
 562   NULL                  // attributes_vendor
 563 };
 564
 565 // This is called when a new output section is created.  This is where
 566 // we handle the SHF_X86_64_LARGE.
 567
 568 void
 569 Target_x86_64::do_new_output_section(Output_section *os) const
 570 {
 571   if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
 572     os->set_is_large_section();
 573 }
 574
 575 // Get the GOT section, creating it if necessary.
 576
 577 Output_data_got<64, false>*
 578 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 579 {
 580   if (this->got_ == NULL)
 581     {
 582       gold_assert(symtab != NULL && layout != NULL);
 583
 584       this->got_ = new Output_data_got<64, false>();
 585
 586       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 587                                       (elfcpp::SHF_ALLOC
 588                                        | elfcpp::SHF_WRITE),
 589                                       this->got_, ORDER_RELRO_LAST,
 590                                       true);
 591
 592       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 593       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 594                                       (elfcpp::SHF_ALLOC
 595                                        | elfcpp::SHF_WRITE),
 596                                       this->got_plt_, ORDER_NON_RELRO_FIRST,
 597                                       false);
 598
 599       // The first three entries are reserved.
 600       this->got_plt_->set_current_data_size(3 * 8);
 601
 602       // Those bytes can go into the relro segment.
 603       layout->increase_relro(3 * 8);
 604
 605       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 606       this->global_offset_table_ =
 607         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 608                                       Symbol_table::PREDEFINED,
 609                                       this->got_plt_,
 610                                       0, 0, elfcpp::STT_OBJECT,
 611                                       elfcpp::STB_LOCAL,
 612                                       elfcpp::STV_HIDDEN, 0,
 613                                       false, false);
 614
 615       // If there are any TLSDESC relocations, they get GOT entries in
 616       // .got.plt after the jump slot entries.
 617       this->got_tlsdesc_ = new Output_data_got<64, false>();
 618       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 619                                       (elfcpp::SHF_ALLOC
 620                                        | elfcpp::SHF_WRITE),
 621                                       this->got_tlsdesc_,
 622                                       ORDER_NON_RELRO_FIRST, false);
 623     }
 624
 625   return this->got_;
 626 }
 627
 628 // Get the dynamic reloc section, creating it if necessary.
 629
 630 Target_x86_64::Reloc_section*
 631 Target_x86_64::rela_dyn_section(Layout* layout)
 632 {
 633   if (this->rela_dyn_ == NULL)
 634     {
 635       gold_assert(layout != NULL);
 636       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 637       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 638                                       elfcpp::SHF_ALLOC, this->rela_dyn_,
 639                                       ORDER_DYNAMIC_RELOCS, false);
 640     }
 641   return this->rela_dyn_;
 642 }
 643
 644 // A class to handle the PLT data.
 645
 646 class Output_data_plt_x86_64 : public Output_section_data
 647 {
 648  public:
 649   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 650
 651   Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
 652                          Output_data_space*);
 653
 654   // Add an entry to the PLT.
 655   void
 656   add_entry(Symbol* gsym);
 657
 658   // Add the reserved TLSDESC_PLT entry to the PLT.
 659   void
 660   reserve_tlsdesc_entry(unsigned int got_offset)
 661   { this->tlsdesc_got_offset_ = got_offset; }
 662
 663   // Return true if a TLSDESC_PLT entry has been reserved.
 664   bool
 665   has_tlsdesc_entry() const
 666   { return this->tlsdesc_got_offset_ != -1U; }
 667
 668   // Return the GOT offset for the reserved TLSDESC_PLT entry.
 669   unsigned int
 670   get_tlsdesc_got_offset() const
 671   { return this->tlsdesc_got_offset_; }
 672
 673   // Return the offset of the reserved TLSDESC_PLT entry.
 674   unsigned int
 675   get_tlsdesc_plt_offset() const
 676   { return (this->count_ + 1) * plt_entry_size; }
 677
 678   // Return the .rela.plt section data.
 679   const Reloc_section*
 680   rela_plt() const
 681   { return this->rel_; }
 682
 683   // Return where the TLSDESC relocations should go.
 684   Reloc_section*
 685   rela_tlsdesc(Layout*);
 686
 687   // Return the number of PLT entries.
 688   unsigned int
 689   entry_count() const
 690   { return this->count_; }
 691
 692   // Return the offset of the first non-reserved PLT entry.
 693   static unsigned int
 694   first_plt_entry_offset()
 695   { return plt_entry_size; }
 696
 697   // Return the size of a PLT entry.
 698   static unsigned int
 699   get_plt_entry_size()
 700   { return plt_entry_size; }
 701
 702  protected:
 703   void
 704   do_adjust_output_section(Output_section* os);
 705
 706   // Write to a map file.
 707   void
 708   do_print_to_mapfile(Mapfile* mapfile) const
 709   { mapfile->print_output_data(this, _("** PLT")); }
 710
 711  private:
 712   // The size of an entry in the PLT.
 713   static const int plt_entry_size = 16;
 714
 715   // The first entry in the PLT.
 716   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 717   // procedure linkage table for both programs and shared objects."
 718   static unsigned char first_plt_entry[plt_entry_size];
 719
 720   // Other entries in the PLT for an executable.
 721   static unsigned char plt_entry[plt_entry_size];
 722
 723   // The reserved TLSDESC entry in the PLT for an executable.
 724   static unsigned char tlsdesc_plt_entry[plt_entry_size];
 725
 726   // Set the final size.
 727   void
 728   set_final_data_size();
 729
 730   // Write out the PLT data.
 731   void
 732   do_write(Output_file*);
 733
 734   // The reloc section.
 735   Reloc_section* rel_;
 736   // The TLSDESC relocs, if necessary.  These must follow the regular
 737   // PLT relocs.
 738   Reloc_section* tlsdesc_rel_;
 739   // The .got section.
 740   Output_data_got<64, false>* got_;
 741   // The .got.plt section.
 742   Output_data_space* got_plt_;
 743   // The number of PLT entries.
 744   unsigned int count_;
 745   // Offset of the reserved TLSDESC_GOT entry when needed.
 746   unsigned int tlsdesc_got_offset_;
 747 };
 748
 749 // Create the PLT section.  The ordinary .got section is an argument,
 750 // since we need to refer to the start.  We also create our own .got
 751 // section just for PLT entries.
 752
 753 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 754                                                Output_data_got<64, false>* got,
 755                                                Output_data_space* got_plt)
 756   : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
 757     count_(0), tlsdesc_got_offset_(-1U)
 758 {
 759   this->rel_ = new Reloc_section(false);
 760   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 761                                   elfcpp::SHF_ALLOC, this->rel_,
 762                                   ORDER_DYNAMIC_PLT_RELOCS, false);
 763 }
 764
 765 void
 766 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 767 {
 768   os->set_entsize(plt_entry_size);
 769 }
 770
 771 // Add an entry to the PLT.
 772
 773 void
 774 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 775 {
 776   gold_assert(!gsym->has_plt_offset());
 777
 778   // Note that when setting the PLT offset we skip the initial
 779   // reserved PLT entry.
 780   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 781
 782   ++this->count_;
 783
 784   section_offset_type got_offset = this->got_plt_->current_data_size();
 785
 786   // Every PLT entry needs a GOT entry which points back to the PLT
 787   // entry (this will be changed by the dynamic linker, normally
 788   // lazily when the function is called).
 789   this->got_plt_->set_current_data_size(got_offset + 8);
 790
 791   // Every PLT entry needs a reloc.
 792   gsym->set_needs_dynsym_entry();
 793   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 794                          got_offset, 0);
 795
 796   // Note that we don't need to save the symbol.  The contents of the
 797   // PLT are independent of which symbols are used.  The symbols only
 798   // appear in the relocations.
 799 }
 800
 801 // Return where the TLSDESC relocations should go, creating it if
 802 // necessary.  These follow the JUMP_SLOT relocations.
 803
 804 Output_data_plt_x86_64::Reloc_section*
 805 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
 806 {
 807   if (this->tlsdesc_rel_ == NULL)
 808     {
 809       this->tlsdesc_rel_ = new Reloc_section(false);
 810       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 811                                       elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
 812                                       ORDER_DYNAMIC_PLT_RELOCS, false);
 813       gold_assert(this->tlsdesc_rel_->output_section() ==
 814                   this->rel_->output_section());
 815     }
 816   return this->tlsdesc_rel_;
 817 }
 818
 819 // Set the final size.
 820 void
 821 Output_data_plt_x86_64::set_final_data_size()
 822 {
 823   unsigned int count = this->count_;
 824   if (this->has_tlsdesc_entry())
 825     ++count;
 826   this->set_data_size((count + 1) * plt_entry_size);
 827 }
 828
 829 // The first entry in the PLT for an executable.
 830
 831 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 832 {
 833   // From AMD64 ABI Draft 0.98, page 76
 834   0xff, 0x35,   // pushq contents of memory address
 835   0, 0, 0, 0,   // replaced with address of .got + 8
 836   0xff, 0x25,   // jmp indirect
 837   0, 0, 0, 0,   // replaced with address of .got + 16
 838   0x90, 0x90, 0x90, 0x90   // noop (x4)
 839 };
 840
 841 // Subsequent entries in the PLT for an executable.
 842
 843 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 844 {
 845   // From AMD64 ABI Draft 0.98, page 76
 846   0xff, 0x25,   // jmpq indirect
 847   0, 0, 0, 0,   // replaced with address of symbol in .got
 848   0x68,         // pushq immediate
 849   0, 0, 0, 0,   // replaced with offset into relocation table
 850   0xe9,         // jmpq relative
 851   0, 0, 0, 0    // replaced with offset to start of .plt
 852 };
 853
 854 // The reserved TLSDESC entry in the PLT for an executable.
 855
 856 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 857 {
 858   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 859   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 860   0xff, 0x35,   // pushq x(%rip)
 861   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 862   0xff, 0x25,   // jmpq *y(%rip)
 863   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 864   0x0f, 0x1f,   // nop
 865   0x40, 0
 866 };
 867
 868 // Write out the PLT.  This uses the hand-coded instructions above,
 869 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 870
 871 void
 872 Output_data_plt_x86_64::do_write(Output_file* of)
 873 {
 874   const off_t offset = this->offset();
 875   const section_size_type oview_size =
 876     convert_to_section_size_type(this->data_size());
 877   unsigned char* const oview = of->get_output_view(offset, oview_size);
 878
 879   const off_t got_file_offset = this->got_plt_->offset();
 880   const section_size_type got_size =
 881     convert_to_section_size_type(this->got_plt_->data_size());
 882   unsigned char* const got_view = of->get_output_view(got_file_offset,
 883                                                       got_size);
 884
 885   unsigned char* pov = oview;
 886
 887   // The base address of the .plt section.
 888   elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
 889   // The base address of the .got section.
 890   elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
 891   // The base address of the PLT portion of the .got section,
 892   // which is where the GOT pointer will point, and where the
 893   // three reserved GOT entries are located.
 894   elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
 895
 896   memcpy(pov, first_plt_entry, plt_entry_size);
 897   // We do a jmp relative to the PC at the end of this instruction.
 898   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 899                                               (got_address + 8
 900                                                - (plt_address + 6)));
 901   elfcpp::Swap<32, false>::writeval(pov + 8,
 902                                     (got_address + 16
 903                                      - (plt_address + 12)));
 904   pov += plt_entry_size;
 905
 906   unsigned char* got_pov = got_view;
 907
 908   memset(got_pov, 0, 24);
 909   got_pov += 24;
 910
 911   unsigned int plt_offset = plt_entry_size;
 912   unsigned int got_offset = 24;
 913   const unsigned int count = this->count_;
 914   for (unsigned int plt_index = 0;
 915        plt_index < count;
 916        ++plt_index,
 917          pov += plt_entry_size,
 918          got_pov += 8,
 919          plt_offset += plt_entry_size,
 920          got_offset += 8)
 921     {
 922       // Set and adjust the PLT entry itself.
 923       memcpy(pov, plt_entry, plt_entry_size);
 924       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 925                                                   (got_address + got_offset
 926                                                    - (plt_address + plt_offset
 927                                                       + 6)));
 928
 929       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 930       elfcpp::Swap<32, false>::writeval(pov + 12,
 931                                         - (plt_offset + plt_entry_size));
 932
 933       // Set the entry in the GOT.
 934       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 935     }
 936
 937   if (this->has_tlsdesc_entry())
 938     {
 939       // Set and adjust the reserved TLSDESC PLT entry.
 940       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
 941       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
 942       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 943                                                   (got_address + 8
 944                                                    - (plt_address + plt_offset
 945                                                       + 6)));
 946       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
 947                                                   (got_base
 948                                                    + tlsdesc_got_offset
 949                                                    - (plt_address + plt_offset
 950                                                       + 12)));
 951       pov += plt_entry_size;
 952     }
 953
 954   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 955   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 956
 957   of->write_output_view(offset, oview_size, oview);
 958   of->write_output_view(got_file_offset, got_size, got_view);
 959 }
 960
 961 // Create the PLT section.
 962
 963 void
 964 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
 965 {
 966   if (this->plt_ == NULL)
 967     {
 968       // Create the GOT sections first.
 969       this->got_section(symtab, layout);
 970
 971       this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
 972                                               this->got_plt_);
 973       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 974                                       (elfcpp::SHF_ALLOC
 975                                        | elfcpp::SHF_EXECINSTR),
 976                                       this->plt_, ORDER_PLT, false);
 977     }
 978 }
 979
 980 // Return the section for TLSDESC relocations.
 981
 982 Target_x86_64::Reloc_section*
 983 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
 984 {
 985   return this->plt_section()->rela_tlsdesc(layout);
 986 }
 987
 988 // Create a PLT entry for a global symbol.
 989
 990 void
 991 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 992                               Symbol* gsym)
 993 {
 994   if (gsym->has_plt_offset())
 995     return;
 996
 997   if (this->plt_ == NULL)
 998     this->make_plt_section(symtab, layout);
 999
1000   this->plt_->add_entry(gsym);
1001 }
1002
1003 // Return the number of entries in the PLT.
1004
1005 unsigned int
1006 Target_x86_64::plt_entry_count() const
1007 {
1008   if (this->plt_ == NULL)
1009     return 0;
1010   return this->plt_->entry_count();
1011 }
1012
1013 // Return the offset of the first non-reserved PLT entry.
1014
1015 unsigned int
1016 Target_x86_64::first_plt_entry_offset() const
1017 {
1018   return Output_data_plt_x86_64::first_plt_entry_offset();
1019 }
1020
1021 // Return the size of each PLT entry.
1022
1023 unsigned int
1024 Target_x86_64::plt_entry_size() const
1025 {
1026   return Output_data_plt_x86_64::get_plt_entry_size();
1027 }
1028
1029 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1030
1031 void
1032 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
1033 {
1034   if (this->tls_base_symbol_defined_)
1035     return;
1036
1037   Output_segment* tls_segment = layout->tls_segment();
1038   if (tls_segment != NULL)
1039     {
1040       bool is_exec = parameters->options().output_is_executable();
1041       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1042                                        Symbol_table::PREDEFINED,
1043                                        tls_segment, 0, 0,
1044                                        elfcpp::STT_TLS,
1045                                        elfcpp::STB_LOCAL,
1046                                        elfcpp::STV_HIDDEN, 0,
1047                                        (is_exec
1048                                         ? Symbol::SEGMENT_END
1049                                         : Symbol::SEGMENT_START),
1050                                        true);
1051     }
1052   this->tls_base_symbol_defined_ = true;
1053 }
1054
1055 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1056
1057 void
1058 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
1059                                              Layout* layout)
1060 {
1061   if (this->plt_ == NULL)
1062     this->make_plt_section(symtab, layout);
1063
1064   if (!this->plt_->has_tlsdesc_entry())
1065     {
1066       // Allocate the TLSDESC_GOT entry.
1067       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1068       unsigned int got_offset = got->add_constant(0);
1069
1070       // Allocate the TLSDESC_PLT entry.
1071       this->plt_->reserve_tlsdesc_entry(got_offset);
1072     }
1073 }
1074
1075 // Create a GOT entry for the TLS module index.
1076
1077 unsigned int
1078 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1079                                    Sized_relobj<64, false>* object)
1080 {
1081   if (this->got_mod_index_offset_ == -1U)
1082     {
1083       gold_assert(symtab != NULL && layout != NULL && object != NULL);
1084       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1085       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1086       unsigned int got_offset = got->add_constant(0);
1087       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1088                           got_offset, 0);
1089       got->add_constant(0);
1090       this->got_mod_index_offset_ = got_offset;
1091     }
1092   return this->got_mod_index_offset_;
1093 }
1094
1095 // Optimize the TLS relocation type based on what we know about the
1096 // symbol.  IS_FINAL is true if the final address of this symbol is
1097 // known at link time.
1098
1099 tls::Tls_optimization
1100 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1101 {
1102   // If we are generating a shared library, then we can't do anything
1103   // in the linker.
1104   if (parameters->options().shared())
1105     return tls::TLSOPT_NONE;
1106
1107   switch (r_type)
1108     {
1109     case elfcpp::R_X86_64_TLSGD:
1110     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1111     case elfcpp::R_X86_64_TLSDESC_CALL:
1112       // These are General-Dynamic which permits fully general TLS
1113       // access.  Since we know that we are generating an executable,
1114       // we can convert this to Initial-Exec.  If we also know that
1115       // this is a local symbol, we can further switch to Local-Exec.
1116       if (is_final)
1117         return tls::TLSOPT_TO_LE;
1118       return tls::TLSOPT_TO_IE;
1119
1120     case elfcpp::R_X86_64_TLSLD:
1121       // This is Local-Dynamic, which refers to a local symbol in the
1122       // dynamic TLS block.  Since we know that we generating an
1123       // executable, we can switch to Local-Exec.
1124       return tls::TLSOPT_TO_LE;
1125
1126     case elfcpp::R_X86_64_DTPOFF32:
1127     case elfcpp::R_X86_64_DTPOFF64:
1128       // Another Local-Dynamic reloc.
1129       return tls::TLSOPT_TO_LE;
1130
1131     case elfcpp::R_X86_64_GOTTPOFF:
1132       // These are Initial-Exec relocs which get the thread offset
1133       // from the GOT.  If we know that we are linking against the
1134       // local symbol, we can switch to Local-Exec, which links the
1135       // thread offset into the instruction.
1136       if (is_final)
1137         return tls::TLSOPT_TO_LE;
1138       return tls::TLSOPT_NONE;
1139
1140     case elfcpp::R_X86_64_TPOFF32:
1141       // When we already have Local-Exec, there is nothing further we
1142       // can do.
1143       return tls::TLSOPT_NONE;
1144
1145     default:
1146       gold_unreachable();
1147     }
1148 }
1149
1150 // Report an unsupported relocation against a local symbol.
1151
1152 void
1153 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
1154                                              unsigned int r_type)
1155 {
1156   gold_error(_("%s: unsupported reloc %u against local symbol"),
1157              object->name().c_str(), r_type);
1158 }
1159
1160 // We are about to emit a dynamic relocation of type R_TYPE.  If the
1161 // dynamic linker does not support it, issue an error.  The GNU linker
1162 // only issues a non-PIC error for an allocated read-only section.
1163 // Here we know the section is allocated, but we don't know that it is
1164 // read-only.  But we check for all the relocation types which the
1165 // glibc dynamic linker supports, so it seems appropriate to issue an
1166 // error even if the section is not read-only.
1167
1168 void
1169 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
1170 {
1171   switch (r_type)
1172     {
1173       // These are the relocation types supported by glibc for x86_64.
1174     case elfcpp::R_X86_64_RELATIVE:
1175     case elfcpp::R_X86_64_GLOB_DAT:
1176     case elfcpp::R_X86_64_JUMP_SLOT:
1177     case elfcpp::R_X86_64_DTPMOD64:
1178     case elfcpp::R_X86_64_DTPOFF64:
1179     case elfcpp::R_X86_64_TPOFF64:
1180     case elfcpp::R_X86_64_64:
1181     case elfcpp::R_X86_64_32:
1182     case elfcpp::R_X86_64_PC32:
1183     case elfcpp::R_X86_64_COPY:
1184       return;
1185
1186     default:
1187       // This prevents us from issuing more than one error per reloc
1188       // section.  But we can still wind up issuing more than one
1189       // error per object file.
1190       if (this->issued_non_pic_error_)
1191         return;
1192       gold_assert(parameters->options().output_is_position_independent());
1193       object->error(_("requires unsupported dynamic reloc; "
1194                       "recompile with -fPIC"));
1195       this->issued_non_pic_error_ = true;
1196       return;
1197
1198     case elfcpp::R_X86_64_NONE:
1199       gold_unreachable();
1200     }
1201 }
1202
1203 // Scan a relocation for a local symbol.
1204
1205 inline void
1206 Target_x86_64::Scan::local(Symbol_table* symtab,
1207                            Layout* layout,
1208                            Target_x86_64* target,
1209                            Sized_relobj<64, false>* object,
1210                            unsigned int data_shndx,
1211                            Output_section* output_section,
1212                            const elfcpp::Rela<64, false>& reloc,
1213                            unsigned int r_type,
1214                            const elfcpp::Sym<64, false>& lsym)
1215 {
1216   switch (r_type)
1217     {
1218     case elfcpp::R_X86_64_NONE:
1219     case elfcpp::R_X86_64_GNU_VTINHERIT:
1220     case elfcpp::R_X86_64_GNU_VTENTRY:
1221       break;
1222
1223     case elfcpp::R_X86_64_64:
1224       // If building a shared library (or a position-independent
1225       // executable), we need to create a dynamic relocation for this
1226       // location.  The relocation applied at link time will apply the
1227       // link-time value, so we flag the location with an
1228       // R_X86_64_RELATIVE relocation so the dynamic loader can
1229       // relocate it easily.
1230       if (parameters->options().output_is_position_independent())
1231         {
1232           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1233           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1234           rela_dyn->add_local_relative(object, r_sym,
1235                                        elfcpp::R_X86_64_RELATIVE,
1236                                        output_section, data_shndx,
1237                                        reloc.get_r_offset(),
1238                                        reloc.get_r_addend());
1239         }
1240       break;
1241
1242     case elfcpp::R_X86_64_32:
1243     case elfcpp::R_X86_64_32S:
1244     case elfcpp::R_X86_64_16:
1245     case elfcpp::R_X86_64_8:
1246       // If building a shared library (or a position-independent
1247       // executable), we need to create a dynamic relocation for this
1248       // location.  We can't use an R_X86_64_RELATIVE relocation
1249       // because that is always a 64-bit relocation.
1250       if (parameters->options().output_is_position_independent())
1251         {
1252           this->check_non_pic(object, r_type);
1253
1254           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1255           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1256           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1257             rela_dyn->add_local(object, r_sym, r_type, output_section,
1258                                 data_shndx, reloc.get_r_offset(),
1259                                 reloc.get_r_addend());
1260           else
1261             {
1262               gold_assert(lsym.get_st_value() == 0);
1263               unsigned int shndx = lsym.get_st_shndx();
1264               bool is_ordinary;
1265               shndx = object->adjust_sym_shndx(r_sym, shndx,
1266                                                &is_ordinary);
1267               if (!is_ordinary)
1268                 object->error(_("section symbol %u has bad shndx %u"),
1269                               r_sym, shndx);
1270               else
1271                 rela_dyn->add_local_section(object, shndx,
1272                                             r_type, output_section,
1273                                             data_shndx, reloc.get_r_offset(),
1274                                             reloc.get_r_addend());
1275             }
1276         }
1277       break;
1278
1279     case elfcpp::R_X86_64_PC64:
1280     case elfcpp::R_X86_64_PC32:
1281     case elfcpp::R_X86_64_PC16:
1282     case elfcpp::R_X86_64_PC8:
1283       break;
1284
1285     case elfcpp::R_X86_64_PLT32:
1286       // Since we know this is a local symbol, we can handle this as a
1287       // PC32 reloc.
1288       break;
1289
1290     case elfcpp::R_X86_64_GOTPC32:
1291     case elfcpp::R_X86_64_GOTOFF64:
1292     case elfcpp::R_X86_64_GOTPC64:
1293     case elfcpp::R_X86_64_PLTOFF64:
1294       // We need a GOT section.
1295       target->got_section(symtab, layout);
1296       // For PLTOFF64, we'd normally want a PLT section, but since we
1297       // know this is a local symbol, no PLT is needed.
1298       break;
1299
1300     case elfcpp::R_X86_64_GOT64:
1301     case elfcpp::R_X86_64_GOT32:
1302     case elfcpp::R_X86_64_GOTPCREL64:
1303     case elfcpp::R_X86_64_GOTPCREL:
1304     case elfcpp::R_X86_64_GOTPLT64:
1305       {
1306         // The symbol requires a GOT entry.
1307         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1308         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1309         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1310           {
1311             // If we are generating a shared object, we need to add a
1312             // dynamic relocation for this symbol's GOT entry.
1313             if (parameters->options().output_is_position_independent())
1314               {
1315                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1316                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1317                 if (r_type != elfcpp::R_X86_64_GOT32)
1318                   rela_dyn->add_local_relative(
1319                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
1320                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1321                 else
1322                   {
1323                     this->check_non_pic(object, r_type);
1324
1325                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1326                     rela_dyn->add_local(
1327                         object, r_sym, r_type, got,
1328                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1329                   }
1330               }
1331           }
1332         // For GOTPLT64, we'd normally want a PLT section, but since
1333         // we know this is a local symbol, no PLT is needed.
1334       }
1335       break;
1336
1337     case elfcpp::R_X86_64_COPY:
1338     case elfcpp::R_X86_64_GLOB_DAT:
1339     case elfcpp::R_X86_64_JUMP_SLOT:
1340     case elfcpp::R_X86_64_RELATIVE:
1341       // These are outstanding tls relocs, which are unexpected when linking
1342     case elfcpp::R_X86_64_TPOFF64:
1343     case elfcpp::R_X86_64_DTPMOD64:
1344     case elfcpp::R_X86_64_TLSDESC:
1345       gold_error(_("%s: unexpected reloc %u in object file"),
1346                  object->name().c_str(), r_type);
1347       break;
1348
1349       // These are initial tls relocs, which are expected when linking
1350     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1351     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1352     case elfcpp::R_X86_64_TLSDESC_CALL:
1353     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1354     case elfcpp::R_X86_64_DTPOFF32:
1355     case elfcpp::R_X86_64_DTPOFF64:
1356     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1357     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1358       {
1359         bool output_is_shared = parameters->options().shared();
1360         const tls::Tls_optimization optimized_type
1361             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1362         switch (r_type)
1363           {
1364           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1365             if (optimized_type == tls::TLSOPT_NONE)
1366               {
1367                 // Create a pair of GOT entries for the module index and
1368                 // dtv-relative offset.
1369                 Output_data_got<64, false>* got
1370                     = target->got_section(symtab, layout);
1371                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1372                 unsigned int shndx = lsym.get_st_shndx();
1373                 bool is_ordinary;
1374                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1375                 if (!is_ordinary)
1376                   object->error(_("local symbol %u has bad shndx %u"),
1377                               r_sym, shndx);
1378                 else
1379                   got->add_local_pair_with_rela(object, r_sym,
1380                                                 shndx,
1381                                                 GOT_TYPE_TLS_PAIR,
1382                                                 target->rela_dyn_section(layout),
1383                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1384               }
1385             else if (optimized_type != tls::TLSOPT_TO_LE)
1386               unsupported_reloc_local(object, r_type);
1387             break;
1388
1389           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1390             target->define_tls_base_symbol(symtab, layout);
1391             if (optimized_type == tls::TLSOPT_NONE)
1392               {
1393                 // Create reserved PLT and GOT entries for the resolver.
1394                 target->reserve_tlsdesc_entries(symtab, layout);
1395
1396                 // Generate a double GOT entry with an
1397                 // R_X86_64_TLSDESC reloc.  The R_X86_64_TLSDESC reloc
1398                 // is resolved lazily, so the GOT entry needs to be in
1399                 // an area in .got.plt, not .got.  Call got_section to
1400                 // make sure the section has been created.
1401                 target->got_section(symtab, layout);
1402                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1403                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1404                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1405                   {
1406                     unsigned int got_offset = got->add_constant(0);
1407                     got->add_constant(0);
1408                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1409                                                  got_offset);
1410                     Reloc_section* rt = target->rela_tlsdesc_section(layout);
1411                     // We store the arguments we need in a vector, and
1412                     // use the index into the vector as the parameter
1413                     // to pass to the target specific routines.
1414                     uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
1415                     void* arg = reinterpret_cast<void*>(intarg);
1416                     rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1417                                             got, got_offset, 0);
1418                   }
1419               }
1420             else if (optimized_type != tls::TLSOPT_TO_LE)
1421               unsupported_reloc_local(object, r_type);
1422             break;
1423
1424           case elfcpp::R_X86_64_TLSDESC_CALL:
1425             break;
1426
1427           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1428             if (optimized_type == tls::TLSOPT_NONE)
1429               {
1430                 // Create a GOT entry for the module index.
1431                 target->got_mod_index_entry(symtab, layout, object);
1432               }
1433             else if (optimized_type != tls::TLSOPT_TO_LE)
1434               unsupported_reloc_local(object, r_type);
1435             break;
1436
1437           case elfcpp::R_X86_64_DTPOFF32:
1438           case elfcpp::R_X86_64_DTPOFF64:
1439             break;
1440
1441           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1442             layout->set_has_static_tls();
1443             if (optimized_type == tls::TLSOPT_NONE)
1444               {
1445                 // Create a GOT entry for the tp-relative offset.
1446                 Output_data_got<64, false>* got
1447                     = target->got_section(symtab, layout);
1448                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1449                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1450                                          target->rela_dyn_section(layout),
1451                                          elfcpp::R_X86_64_TPOFF64);
1452               }
1453             else if (optimized_type != tls::TLSOPT_TO_LE)
1454               unsupported_reloc_local(object, r_type);
1455             break;
1456
1457           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1458             layout->set_has_static_tls();
1459             if (output_is_shared)
1460               unsupported_reloc_local(object, r_type);
1461             break;
1462
1463           default:
1464             gold_unreachable();
1465           }
1466       }
1467       break;
1468
1469     case elfcpp::R_X86_64_SIZE32:
1470     case elfcpp::R_X86_64_SIZE64:
1471     default:
1472       gold_error(_("%s: unsupported reloc %u against local symbol"),
1473                  object->name().c_str(), r_type);
1474       break;
1475     }
1476 }
1477
1478
1479 // Report an unsupported relocation against a global symbol.
1480
1481 void
1482 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1483                                               unsigned int r_type,
1484                                               Symbol* gsym)
1485 {
1486   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1487              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1488 }
1489
1490 // Returns true if this relocation type could be that of a function pointer.
1491 inline bool
1492 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
1493 {
1494   switch (r_type)
1495     {
1496     case elfcpp::R_X86_64_64:
1497     case elfcpp::R_X86_64_32:
1498     case elfcpp::R_X86_64_32S:
1499     case elfcpp::R_X86_64_16:
1500     case elfcpp::R_X86_64_8:
1501     case elfcpp::R_X86_64_GOT64:
1502     case elfcpp::R_X86_64_GOT32:
1503     case elfcpp::R_X86_64_GOTPCREL64:
1504     case elfcpp::R_X86_64_GOTPCREL:
1505     case elfcpp::R_X86_64_GOTPLT64:
1506       {
1507         return true;
1508       }
1509     }
1510   return false;
1511 }
1512
1513 // For safe ICF, scan a relocation for a local symbol to check if it
1514 // corresponds to a function pointer being taken.  In that case mark
1515 // the function whose pointer was taken as not foldable.
1516
1517 inline bool
1518 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1519   Symbol_table* ,
1520   Layout* ,
1521   Target_x86_64* ,
1522   Sized_relobj<64, false>* ,
1523   unsigned int ,
1524   Output_section* ,
1525   const elfcpp::Rela<64, false>& ,
1526   unsigned int r_type,
1527   const elfcpp::Sym<64, false>&)
1528 {
1529   // When building a shared library, do not fold any local symbols as it is
1530   // not possible to distinguish pointer taken versus a call by looking at
1531   // the relocation types.
1532   return (parameters->options().shared()
1533           || possible_function_pointer_reloc(r_type));
1534 }
1535
1536 // For safe ICF, scan a relocation for a global symbol to check if it
1537 // corresponds to a function pointer being taken.  In that case mark
1538 // the function whose pointer was taken as not foldable.
1539
1540 inline bool
1541 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1542   Symbol_table*,
1543   Layout* ,
1544   Target_x86_64* ,
1545   Sized_relobj<64, false>* ,
1546   unsigned int ,
1547   Output_section* ,
1548   const elfcpp::Rela<64, false>& ,
1549   unsigned int r_type,
1550   Symbol* gsym)
1551 {
1552   // When building a shared library, do not fold symbols whose visibility
1553   // is hidden, internal or protected.
1554   return ((parameters->options().shared()
1555            && (gsym->visibility() == elfcpp::STV_INTERNAL
1556                || gsym->visibility() == elfcpp::STV_PROTECTED
1557                || gsym->visibility() == elfcpp::STV_HIDDEN))
1558           || possible_function_pointer_reloc(r_type));
1559 }
1560
1561 // Scan a relocation for a global symbol.
1562
1563 inline void
1564 Target_x86_64::Scan::global(Symbol_table* symtab,
1565                             Layout* layout,
1566                             Target_x86_64* target,
1567                             Sized_relobj<64, false>* object,
1568                             unsigned int data_shndx,
1569                             Output_section* output_section,
1570                             const elfcpp::Rela<64, false>& reloc,
1571                             unsigned int r_type,
1572                             Symbol* gsym)
1573 {
1574   switch (r_type)
1575     {
1576     case elfcpp::R_X86_64_NONE:
1577     case elfcpp::R_X86_64_GNU_VTINHERIT:
1578     case elfcpp::R_X86_64_GNU_VTENTRY:
1579       break;
1580
1581     case elfcpp::R_X86_64_64:
1582     case elfcpp::R_X86_64_32:
1583     case elfcpp::R_X86_64_32S:
1584     case elfcpp::R_X86_64_16:
1585     case elfcpp::R_X86_64_8:
1586       {
1587         // Make a PLT entry if necessary.
1588         if (gsym->needs_plt_entry())
1589           {
1590             target->make_plt_entry(symtab, layout, gsym);
1591             // Since this is not a PC-relative relocation, we may be
1592             // taking the address of a function. In that case we need to
1593             // set the entry in the dynamic symbol table to the address of
1594             // the PLT entry.
1595             if (gsym->is_from_dynobj() && !parameters->options().shared())
1596               gsym->set_needs_dynsym_value();
1597           }
1598         // Make a dynamic relocation if necessary.
1599         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1600           {
1601             if (gsym->may_need_copy_reloc())
1602               {
1603                 target->copy_reloc(symtab, layout, object,
1604                                    data_shndx, output_section, gsym, reloc);
1605               }
1606             else if (r_type == elfcpp::R_X86_64_64
1607                      && gsym->can_use_relative_reloc(false))
1608               {
1609                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1610                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1611                                               output_section, object,
1612                                               data_shndx, reloc.get_r_offset(),
1613                                               reloc.get_r_addend());
1614               }
1615             else
1616               {
1617                 this->check_non_pic(object, r_type);
1618                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1619                 rela_dyn->add_global(gsym, r_type, output_section, object,
1620                                      data_shndx, reloc.get_r_offset(),
1621                                      reloc.get_r_addend());
1622               }
1623           }
1624       }
1625       break;
1626
1627     case elfcpp::R_X86_64_PC64:
1628     case elfcpp::R_X86_64_PC32:
1629     case elfcpp::R_X86_64_PC16:
1630     case elfcpp::R_X86_64_PC8:
1631       {
1632         // Make a PLT entry if necessary.
1633         if (gsym->needs_plt_entry())
1634           target->make_plt_entry(symtab, layout, gsym);
1635         // Make a dynamic relocation if necessary.
1636         int flags = Symbol::NON_PIC_REF;
1637         if (gsym->is_func())
1638           flags |= Symbol::FUNCTION_CALL;
1639         if (gsym->needs_dynamic_reloc(flags))
1640           {
1641             if (gsym->may_need_copy_reloc())
1642               {
1643                 target->copy_reloc(symtab, layout, object,
1644                                    data_shndx, output_section, gsym, reloc);
1645               }
1646             else
1647               {
1648                 this->check_non_pic(object, r_type);
1649                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1650                 rela_dyn->add_global(gsym, r_type, output_section, object,
1651                                      data_shndx, reloc.get_r_offset(),
1652                                      reloc.get_r_addend());
1653               }
1654           }
1655       }
1656       break;
1657
1658     case elfcpp::R_X86_64_GOT64:
1659     case elfcpp::R_X86_64_GOT32:
1660     case elfcpp::R_X86_64_GOTPCREL64:
1661     case elfcpp::R_X86_64_GOTPCREL:
1662     case elfcpp::R_X86_64_GOTPLT64:
1663       {
1664         // The symbol requires a GOT entry.
1665         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1666         if (gsym->final_value_is_known())
1667           got->add_global(gsym, GOT_TYPE_STANDARD);
1668         else
1669           {
1670             // If this symbol is not fully resolved, we need to add a
1671             // dynamic relocation for it.
1672             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1673             if (gsym->is_from_dynobj()
1674                 || gsym->is_undefined()
1675                 || gsym->is_preemptible())
1676               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1677                                         elfcpp::R_X86_64_GLOB_DAT);
1678             else
1679               {
1680                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1681                   rela_dyn->add_global_relative(
1682                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1683                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1684               }
1685           }
1686         // For GOTPLT64, we also need a PLT entry (but only if the
1687         // symbol is not fully resolved).
1688         if (r_type == elfcpp::R_X86_64_GOTPLT64
1689             && !gsym->final_value_is_known())
1690           target->make_plt_entry(symtab, layout, gsym);
1691       }
1692       break;
1693
1694     case elfcpp::R_X86_64_PLT32:
1695       // If the symbol is fully resolved, this is just a PC32 reloc.
1696       // Otherwise we need a PLT entry.
1697       if (gsym->final_value_is_known())
1698         break;
1699       // If building a shared library, we can also skip the PLT entry
1700       // if the symbol is defined in the output file and is protected
1701       // or hidden.
1702       if (gsym->is_defined()
1703           && !gsym->is_from_dynobj()
1704           && !gsym->is_preemptible())
1705         break;
1706       target->make_plt_entry(symtab, layout, gsym);
1707       break;
1708
1709     case elfcpp::R_X86_64_GOTPC32:
1710     case elfcpp::R_X86_64_GOTOFF64:
1711     case elfcpp::R_X86_64_GOTPC64:
1712     case elfcpp::R_X86_64_PLTOFF64:
1713       // We need a GOT section.
1714       target->got_section(symtab, layout);
1715       // For PLTOFF64, we also need a PLT entry (but only if the
1716       // symbol is not fully resolved).
1717       if (r_type == elfcpp::R_X86_64_PLTOFF64
1718           && !gsym->final_value_is_known())
1719         target->make_plt_entry(symtab, layout, gsym);
1720       break;
1721
1722     case elfcpp::R_X86_64_COPY:
1723     case elfcpp::R_X86_64_GLOB_DAT:
1724     case elfcpp::R_X86_64_JUMP_SLOT:
1725     case elfcpp::R_X86_64_RELATIVE:
1726       // These are outstanding tls relocs, which are unexpected when linking
1727     case elfcpp::R_X86_64_TPOFF64:
1728     case elfcpp::R_X86_64_DTPMOD64:
1729     case elfcpp::R_X86_64_TLSDESC:
1730       gold_error(_("%s: unexpected reloc %u in object file"),
1731                  object->name().c_str(), r_type);
1732       break;
1733
1734       // These are initial tls relocs, which are expected for global()
1735     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1736     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1737     case elfcpp::R_X86_64_TLSDESC_CALL:
1738     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1739     case elfcpp::R_X86_64_DTPOFF32:
1740     case elfcpp::R_X86_64_DTPOFF64:
1741     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1742     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1743       {
1744         const bool is_final = gsym->final_value_is_known();
1745         const tls::Tls_optimization optimized_type
1746             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1747         switch (r_type)
1748           {
1749           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1750             if (optimized_type == tls::TLSOPT_NONE)
1751               {
1752                 // Create a pair of GOT entries for the module index and
1753                 // dtv-relative offset.
1754                 Output_data_got<64, false>* got
1755                     = target->got_section(symtab, layout);
1756                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1757                                                target->rela_dyn_section(layout),
1758                                                elfcpp::R_X86_64_DTPMOD64,
1759                                                elfcpp::R_X86_64_DTPOFF64);
1760               }
1761             else if (optimized_type == tls::TLSOPT_TO_IE)
1762               {
1763                 // Create a GOT entry for the tp-relative offset.
1764                 Output_data_got<64, false>* got
1765                     = target->got_section(symtab, layout);
1766                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1767                                           target->rela_dyn_section(layout),
1768                                           elfcpp::R_X86_64_TPOFF64);
1769               }
1770             else if (optimized_type != tls::TLSOPT_TO_LE)
1771               unsupported_reloc_global(object, r_type, gsym);
1772             break;
1773
1774           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1775             target->define_tls_base_symbol(symtab, layout);
1776             if (optimized_type == tls::TLSOPT_NONE)
1777               {
1778                 // Create reserved PLT and GOT entries for the resolver.
1779                 target->reserve_tlsdesc_entries(symtab, layout);
1780
1781                 // Create a double GOT entry with an R_X86_64_TLSDESC
1782                 // reloc.  The R_X86_64_TLSDESC reloc is resolved
1783                 // lazily, so the GOT entry needs to be in an area in
1784                 // .got.plt, not .got.  Call got_section to make sure
1785                 // the section has been created.
1786                 target->got_section(symtab, layout);
1787                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1788                 Reloc_section *rt = target->rela_tlsdesc_section(layout);
1789                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
1790                                                elfcpp::R_X86_64_TLSDESC, 0);
1791               }
1792             else if (optimized_type == tls::TLSOPT_TO_IE)
1793               {
1794                 // Create a GOT entry for the tp-relative offset.
1795                 Output_data_got<64, false>* got
1796                     = target->got_section(symtab, layout);
1797                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1798                                           target->rela_dyn_section(layout),
1799                                           elfcpp::R_X86_64_TPOFF64);
1800               }
1801             else if (optimized_type != tls::TLSOPT_TO_LE)
1802               unsupported_reloc_global(object, r_type, gsym);
1803             break;
1804
1805           case elfcpp::R_X86_64_TLSDESC_CALL:
1806             break;
1807
1808           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1809             if (optimized_type == tls::TLSOPT_NONE)
1810               {
1811                 // Create a GOT entry for the module index.
1812                 target->got_mod_index_entry(symtab, layout, object);
1813               }
1814             else if (optimized_type != tls::TLSOPT_TO_LE)
1815               unsupported_reloc_global(object, r_type, gsym);
1816             break;
1817
1818           case elfcpp::R_X86_64_DTPOFF32:
1819           case elfcpp::R_X86_64_DTPOFF64:
1820             break;
1821
1822           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1823             layout->set_has_static_tls();
1824             if (optimized_type == tls::TLSOPT_NONE)
1825               {
1826                 // Create a GOT entry for the tp-relative offset.
1827                 Output_data_got<64, false>* got
1828                     = target->got_section(symtab, layout);
1829                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1830                                           target->rela_dyn_section(layout),
1831                                           elfcpp::R_X86_64_TPOFF64);
1832               }
1833             else if (optimized_type != tls::TLSOPT_TO_LE)
1834               unsupported_reloc_global(object, r_type, gsym);
1835             break;
1836
1837           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1838             layout->set_has_static_tls();
1839             if (parameters->options().shared())
1840               unsupported_reloc_local(object, r_type);
1841             break;
1842
1843           default:
1844             gold_unreachable();
1845           }
1846       }
1847       break;
1848
1849     case elfcpp::R_X86_64_SIZE32:
1850     case elfcpp::R_X86_64_SIZE64:
1851     default:
1852       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1853                  object->name().c_str(), r_type,
1854                  gsym->demangled_name().c_str());
1855       break;
1856     }
1857 }
1858
1859 void
1860 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
1861                                  Layout* layout,
1862                                  Sized_relobj<64, false>* object,
1863                                  unsigned int data_shndx,
1864                                  unsigned int sh_type,
1865                                  const unsigned char* prelocs,
1866                                  size_t reloc_count,
1867                                  Output_section* output_section,
1868                                  bool needs_special_offset_handling,
1869                                  size_t local_symbol_count,
1870                                  const unsigned char* plocal_symbols)
1871 {
1872
1873   if (sh_type == elfcpp::SHT_REL)
1874     {
1875       return;
1876     }
1877
1878    gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1879                            Target_x86_64::Scan,
1880                            Target_x86_64::Relocatable_size_for_reloc>(
1881     symtab,
1882     layout,
1883     this,
1884     object,
1885     data_shndx,
1886     prelocs,
1887     reloc_count,
1888     output_section,
1889     needs_special_offset_handling,
1890     local_symbol_count,
1891     plocal_symbols);
1892
1893 }
1894 // Scan relocations for a section.
1895
1896 void
1897 Target_x86_64::scan_relocs(Symbol_table* symtab,
1898                            Layout* layout,
1899                            Sized_relobj<64, false>* object,
1900                            unsigned int data_shndx,
1901                            unsigned int sh_type,
1902                            const unsigned char* prelocs,
1903                            size_t reloc_count,
1904                            Output_section* output_section,
1905                            bool needs_special_offset_handling,
1906                            size_t local_symbol_count,
1907                            const unsigned char* plocal_symbols)
1908 {
1909   if (sh_type == elfcpp::SHT_REL)
1910     {
1911       gold_error(_("%s: unsupported REL reloc section"),
1912                  object->name().c_str());
1913       return;
1914     }
1915
1916   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1917       Target_x86_64::Scan>(
1918     symtab,
1919     layout,
1920     this,
1921     object,
1922     data_shndx,
1923     prelocs,
1924     reloc_count,
1925     output_section,
1926     needs_special_offset_handling,
1927     local_symbol_count,
1928     plocal_symbols);
1929 }
1930
1931 // Finalize the sections.
1932
1933 void
1934 Target_x86_64::do_finalize_sections(
1935     Layout* layout,
1936     const Input_objects*,
1937     Symbol_table* symtab)
1938 {
1939   const Reloc_section* rel_plt = (this->plt_ == NULL
1940                                   ? NULL
1941                                   : this->plt_->rela_plt());
1942   layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
1943                                   this->rela_dyn_, true, false);
1944
1945   // Fill in some more dynamic tags.
1946   Output_data_dynamic* const odyn = layout->dynamic_data();
1947   if (odyn != NULL)
1948     {
1949       if (this->plt_ != NULL
1950           && this->plt_->output_section() != NULL
1951           && this->plt_->has_tlsdesc_entry())
1952         {
1953           unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
1954           unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
1955           this->got_->finalize_data_size();
1956           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
1957                                         this->plt_, plt_offset);
1958           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
1959                                         this->got_, got_offset);
1960         }
1961     }
1962
1963   // Emit any relocs we saved in an attempt to avoid generating COPY
1964   // relocs.
1965   if (this->copy_relocs_.any_saved_relocs())
1966     this->copy_relocs_.emit(this->rela_dyn_section(layout));
1967
1968   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1969   // the .got.plt section.
1970   Symbol* sym = this->global_offset_table_;
1971   if (sym != NULL)
1972     {
1973       uint64_t data_size = this->got_plt_->current_data_size();
1974       symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
1975     }
1976 }
1977
1978 // Perform a relocation.
1979
1980 inline bool
1981 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1982                                   Target_x86_64* target,
1983                                   Output_section*,
1984                                   size_t relnum,
1985                                   const elfcpp::Rela<64, false>& rela,
1986                                   unsigned int r_type,
1987                                   const Sized_symbol<64>* gsym,
1988                                   const Symbol_value<64>* psymval,
1989                                   unsigned char* view,
1990                                   elfcpp::Elf_types<64>::Elf_Addr address,
1991                                   section_size_type view_size)
1992 {
1993   if (this->skip_call_tls_get_addr_)
1994     {
1995       if ((r_type != elfcpp::R_X86_64_PLT32
1996            && r_type != elfcpp::R_X86_64_PC32)
1997           || gsym == NULL
1998           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1999         {
2000           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2001                                  _("missing expected TLS relocation"));
2002         }
2003       else
2004         {
2005           this->skip_call_tls_get_addr_ = false;
2006           return false;
2007         }
2008     }
2009
2010   // Pick the value to use for symbols defined in shared objects.
2011   Symbol_value<64> symval;
2012   if (gsym != NULL
2013       && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
2014                               || r_type == elfcpp::R_X86_64_PC32
2015                               || r_type == elfcpp::R_X86_64_PC16
2016                               || r_type == elfcpp::R_X86_64_PC8))
2017     {
2018       symval.set_output_value(target->plt_section()->address()
2019                               + gsym->plt_offset());
2020       psymval = &symval;
2021     }
2022
2023   const Sized_relobj<64, false>* object = relinfo->object;
2024   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2025
2026   // Get the GOT offset if needed.
2027   // The GOT pointer points to the end of the GOT section.
2028   // We need to subtract the size of the GOT section to get
2029   // the actual offset to use in the relocation.
2030   bool have_got_offset = false;
2031   unsigned int got_offset = 0;
2032   switch (r_type)
2033     {
2034     case elfcpp::R_X86_64_GOT32:
2035     case elfcpp::R_X86_64_GOT64:
2036     case elfcpp::R_X86_64_GOTPLT64:
2037     case elfcpp::R_X86_64_GOTPCREL:
2038     case elfcpp::R_X86_64_GOTPCREL64:
2039       if (gsym != NULL)
2040         {
2041           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
2042           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
2043         }
2044       else
2045         {
2046           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2047           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
2048           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
2049                         - target->got_size());
2050         }
2051       have_got_offset = true;
2052       break;
2053
2054     default:
2055       break;
2056     }
2057
2058   switch (r_type)
2059     {
2060     case elfcpp::R_X86_64_NONE:
2061     case elfcpp::R_X86_64_GNU_VTINHERIT:
2062     case elfcpp::R_X86_64_GNU_VTENTRY:
2063       break;
2064
2065     case elfcpp::R_X86_64_64:
2066       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
2067       break;
2068
2069     case elfcpp::R_X86_64_PC64:
2070       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
2071                                               address);
2072       break;
2073
2074     case elfcpp::R_X86_64_32:
2075       // FIXME: we need to verify that value + addend fits into 32 bits:
2076       //    uint64_t x = value + addend;
2077       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2078       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2079       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2080       break;
2081
2082     case elfcpp::R_X86_64_32S:
2083       // FIXME: we need to verify that value + addend fits into 32 bits:
2084       //    int64_t x = value + addend;   // note this quantity is signed!
2085       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
2086       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2087       break;
2088
2089     case elfcpp::R_X86_64_PC32:
2090       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2091                                               address);
2092       break;
2093
2094     case elfcpp::R_X86_64_16:
2095       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2096       break;
2097
2098     case elfcpp::R_X86_64_PC16:
2099       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2100                                               address);
2101       break;
2102
2103     case elfcpp::R_X86_64_8:
2104       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2105       break;
2106
2107     case elfcpp::R_X86_64_PC8:
2108       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2109                                              address);
2110       break;
2111
2112     case elfcpp::R_X86_64_PLT32:
2113       gold_assert(gsym == NULL
2114                   || gsym->has_plt_offset()
2115                   || gsym->final_value_is_known()
2116                   || (gsym->is_defined()
2117                       && !gsym->is_from_dynobj()
2118                       && !gsym->is_preemptible()));
2119       // Note: while this code looks the same as for R_X86_64_PC32, it
2120       // behaves differently because psymval was set to point to
2121       // the PLT entry, rather than the symbol, in Scan::global().
2122       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2123                                               address);
2124       break;
2125
2126     case elfcpp::R_X86_64_PLTOFF64:
2127       {
2128         gold_assert(gsym);
2129         gold_assert(gsym->has_plt_offset()
2130                     || gsym->final_value_is_known());
2131         elfcpp::Elf_types<64>::Elf_Addr got_address;
2132         got_address = target->got_section(NULL, NULL)->address();
2133         Relocate_functions<64, false>::rela64(view, object, psymval,
2134                                               addend - got_address);
2135       }
2136
2137     case elfcpp::R_X86_64_GOT32:
2138       gold_assert(have_got_offset);
2139       Relocate_functions<64, false>::rela32(view, got_offset, addend);
2140       break;
2141
2142     case elfcpp::R_X86_64_GOTPC32:
2143       {
2144         gold_assert(gsym);
2145         elfcpp::Elf_types<64>::Elf_Addr value;
2146         value = target->got_plt_section()->address();
2147         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2148       }
2149       break;
2150
2151     case elfcpp::R_X86_64_GOT64:
2152       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2153       // Since we always add a PLT entry, this is equivalent.
2154     case elfcpp::R_X86_64_GOTPLT64:
2155       gold_assert(have_got_offset);
2156       Relocate_functions<64, false>::rela64(view, got_offset, addend);
2157       break;
2158
2159     case elfcpp::R_X86_64_GOTPC64:
2160       {
2161         gold_assert(gsym);
2162         elfcpp::Elf_types<64>::Elf_Addr value;
2163         value = target->got_plt_section()->address();
2164         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2165       }
2166       break;
2167
2168     case elfcpp::R_X86_64_GOTOFF64:
2169       {
2170         elfcpp::Elf_types<64>::Elf_Addr value;
2171         value = (psymval->value(object, 0)
2172                  - target->got_plt_section()->address());
2173         Relocate_functions<64, false>::rela64(view, value, addend);
2174       }
2175       break;
2176
2177     case elfcpp::R_X86_64_GOTPCREL:
2178       {
2179         gold_assert(have_got_offset);
2180         elfcpp::Elf_types<64>::Elf_Addr value;
2181         value = target->got_plt_section()->address() + got_offset;
2182         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2183       }
2184       break;
2185
2186     case elfcpp::R_X86_64_GOTPCREL64:
2187       {
2188         gold_assert(have_got_offset);
2189         elfcpp::Elf_types<64>::Elf_Addr value;
2190         value = target->got_plt_section()->address() + got_offset;
2191         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2192       }
2193       break;
2194
2195     case elfcpp::R_X86_64_COPY:
2196     case elfcpp::R_X86_64_GLOB_DAT:
2197     case elfcpp::R_X86_64_JUMP_SLOT:
2198     case elfcpp::R_X86_64_RELATIVE:
2199       // These are outstanding tls relocs, which are unexpected when linking
2200     case elfcpp::R_X86_64_TPOFF64:
2201     case elfcpp::R_X86_64_DTPMOD64:
2202     case elfcpp::R_X86_64_TLSDESC:
2203       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2204                              _("unexpected reloc %u in object file"),
2205                              r_type);
2206       break;
2207
2208       // These are initial tls relocs, which are expected when linking
2209     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2210     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2211     case elfcpp::R_X86_64_TLSDESC_CALL:
2212     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2213     case elfcpp::R_X86_64_DTPOFF32:
2214     case elfcpp::R_X86_64_DTPOFF64:
2215     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2216     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2217       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
2218                          view, address, view_size);
2219       break;
2220
2221     case elfcpp::R_X86_64_SIZE32:
2222     case elfcpp::R_X86_64_SIZE64:
2223     default:
2224       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2225                              _("unsupported reloc %u"),
2226                              r_type);
2227       break;
2228     }
2229
2230   return true;
2231 }
2232
2233 // Perform a TLS relocation.
2234
2235 inline void
2236 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
2237                                       Target_x86_64* target,
2238                                       size_t relnum,
2239                                       const elfcpp::Rela<64, false>& rela,
2240                                       unsigned int r_type,
2241                                       const Sized_symbol<64>* gsym,
2242                                       const Symbol_value<64>* psymval,
2243                                       unsigned char* view,
2244                                       elfcpp::Elf_types<64>::Elf_Addr address,
2245                                       section_size_type view_size)
2246 {
2247   Output_segment* tls_segment = relinfo->layout->tls_segment();
2248
2249   const Sized_relobj<64, false>* object = relinfo->object;
2250   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2251
2252   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
2253
2254   const bool is_final = (gsym == NULL
2255                          ? !parameters->options().shared()
2256                          : gsym->final_value_is_known());
2257   const tls::Tls_optimization optimized_type
2258       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
2259   switch (r_type)
2260     {
2261     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2262       this->saw_tls_block_reloc_ = true;
2263       if (optimized_type == tls::TLSOPT_TO_LE)
2264         {
2265           gold_assert(tls_segment != NULL);
2266           this->tls_gd_to_le(relinfo, relnum, tls_segment,
2267                              rela, r_type, value, view,
2268                              view_size);
2269           break;
2270         }
2271       else
2272         {
2273           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2274                                    ? GOT_TYPE_TLS_OFFSET
2275                                    : GOT_TYPE_TLS_PAIR);
2276           unsigned int got_offset;
2277           if (gsym != NULL)
2278             {
2279               gold_assert(gsym->has_got_offset(got_type));
2280               got_offset = gsym->got_offset(got_type) - target->got_size();
2281             }
2282           else
2283             {
2284               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2285               gold_assert(object->local_has_got_offset(r_sym, got_type));
2286               got_offset = (object->local_got_offset(r_sym, got_type)
2287                             - target->got_size());
2288             }
2289           if (optimized_type == tls::TLSOPT_TO_IE)
2290             {
2291               gold_assert(tls_segment != NULL);
2292               value = target->got_plt_section()->address() + got_offset;
2293               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2294                                  value, view, address, view_size);
2295               break;
2296             }
2297           else if (optimized_type == tls::TLSOPT_NONE)
2298             {
2299               // Relocate the field with the offset of the pair of GOT
2300               // entries.
2301               value = target->got_plt_section()->address() + got_offset;
2302               Relocate_functions<64, false>::pcrela32(view, value, addend,
2303                                                       address);
2304               break;
2305             }
2306         }
2307       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2308                              _("unsupported reloc %u"), r_type);
2309       break;
2310
2311     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2312     case elfcpp::R_X86_64_TLSDESC_CALL:
2313       this->saw_tls_block_reloc_ = true;
2314       if (optimized_type == tls::TLSOPT_TO_LE)
2315         {
2316           gold_assert(tls_segment != NULL);
2317           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2318                                   rela, r_type, value, view,
2319                                   view_size);
2320           break;
2321         }
2322       else
2323         {
2324           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2325                                    ? GOT_TYPE_TLS_OFFSET
2326                                    : GOT_TYPE_TLS_DESC);
2327           unsigned int got_offset = 0;
2328           if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
2329               && optimized_type == tls::TLSOPT_NONE)
2330             {
2331               // We created GOT entries in the .got.tlsdesc portion of
2332               // the .got.plt section, but the offset stored in the
2333               // symbol is the offset within .got.tlsdesc.
2334               got_offset = (target->got_size()
2335                             + target->got_plt_section()->data_size());
2336             }
2337           if (gsym != NULL)
2338             {
2339               gold_assert(gsym->has_got_offset(got_type));
2340               got_offset += gsym->got_offset(got_type) - target->got_size();
2341             }
2342           else
2343             {
2344               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2345               gold_assert(object->local_has_got_offset(r_sym, got_type));
2346               got_offset += (object->local_got_offset(r_sym, got_type)
2347                              - target->got_size());
2348             }
2349           if (optimized_type == tls::TLSOPT_TO_IE)
2350             {
2351               gold_assert(tls_segment != NULL);
2352               value = target->got_plt_section()->address() + got_offset;
2353               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2354                                       rela, r_type, value, view, address,
2355                                       view_size);
2356               break;
2357             }
2358           else if (optimized_type == tls::TLSOPT_NONE)
2359             {
2360               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2361                 {
2362                   // Relocate the field with the offset of the pair of GOT
2363                   // entries.
2364                   value = target->got_plt_section()->address() + got_offset;
2365                   Relocate_functions<64, false>::pcrela32(view, value, addend,
2366                                                           address);
2367                 }
2368               break;
2369             }
2370         }
2371       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2372                              _("unsupported reloc %u"), r_type);
2373       break;
2374
2375     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2376       this->saw_tls_block_reloc_ = true;
2377       if (optimized_type == tls::TLSOPT_TO_LE)
2378         {
2379           gold_assert(tls_segment != NULL);
2380           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2381                              value, view, view_size);
2382           break;
2383         }
2384       else if (optimized_type == tls::TLSOPT_NONE)
2385         {
2386           // Relocate the field with the offset of the GOT entry for
2387           // the module index.
2388           unsigned int got_offset;
2389           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2390                         - target->got_size());
2391           value = target->got_plt_section()->address() + got_offset;
2392           Relocate_functions<64, false>::pcrela32(view, value, addend,
2393                                                   address);
2394           break;
2395         }
2396       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2397                              _("unsupported reloc %u"), r_type);
2398       break;
2399
2400     case elfcpp::R_X86_64_DTPOFF32:
2401       if (optimized_type == tls::TLSOPT_TO_LE)
2402         {
2403           // This relocation type is used in debugging information.
2404           // In that case we need to not optimize the value.  If we
2405           // haven't seen a TLSLD reloc, then we assume we should not
2406           // optimize this reloc.
2407           if (this->saw_tls_block_reloc_)
2408             {
2409               gold_assert(tls_segment != NULL);
2410               value -= tls_segment->memsz();
2411             }
2412         }
2413       Relocate_functions<64, false>::rela32(view, value, addend);
2414       break;
2415
2416     case elfcpp::R_X86_64_DTPOFF64:
2417       if (optimized_type == tls::TLSOPT_TO_LE)
2418         {
2419           // See R_X86_64_DTPOFF32, just above, for why we test this.
2420           if (this->saw_tls_block_reloc_)
2421             {
2422               gold_assert(tls_segment != NULL);
2423               value -= tls_segment->memsz();
2424             }
2425         }
2426       Relocate_functions<64, false>::rela64(view, value, addend);
2427       break;
2428
2429     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2430       if (optimized_type == tls::TLSOPT_TO_LE)
2431         {
2432           gold_assert(tls_segment != NULL);
2433           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2434                                                 rela, r_type, value, view,
2435                                                 view_size);
2436           break;
2437         }
2438       else if (optimized_type == tls::TLSOPT_NONE)
2439         {
2440           // Relocate the field with the offset of the GOT entry for
2441           // the tp-relative offset of the symbol.
2442           unsigned int got_offset;
2443           if (gsym != NULL)
2444             {
2445               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2446               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2447                             - target->got_size());
2448             }
2449           else
2450             {
2451               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2452               gold_assert(object->local_has_got_offset(r_sym,
2453                                                        GOT_TYPE_TLS_OFFSET));
2454               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2455                             - target->got_size());
2456             }
2457           value = target->got_plt_section()->address() + got_offset;
2458           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2459           break;
2460         }
2461       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2462                              _("unsupported reloc type %u"),
2463                              r_type);
2464       break;
2465
2466     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2467       value -= tls_segment->memsz();
2468       Relocate_functions<64, false>::rela32(view, value, addend);
2469       break;
2470     }
2471 }
2472
2473 // Do a relocation in which we convert a TLS General-Dynamic to an
2474 // Initial-Exec.
2475
2476 inline void
2477 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2478                                       size_t relnum,
2479                                       Output_segment*,
2480                                       const elfcpp::Rela<64, false>& rela,
2481                                       unsigned int,
2482                                       elfcpp::Elf_types<64>::Elf_Addr value,
2483                                       unsigned char* view,
2484                                       elfcpp::Elf_types<64>::Elf_Addr address,
2485                                       section_size_type view_size)
2486 {
2487   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2488   // .word 0x6666; rex64; call __tls_get_addr
2489   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2490
2491   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2492   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2493
2494   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2495                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2496   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2497                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2498
2499   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2500
2501   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2502   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2503
2504   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2505   // We can skip it.
2506   this->skip_call_tls_get_addr_ = true;
2507 }
2508
2509 // Do a relocation in which we convert a TLS General-Dynamic to a
2510 // Local-Exec.
2511
2512 inline void
2513 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2514                                       size_t relnum,
2515                                       Output_segment* tls_segment,
2516                                       const elfcpp::Rela<64, false>& rela,
2517                                       unsigned int,
2518                                       elfcpp::Elf_types<64>::Elf_Addr value,
2519                                       unsigned char* view,
2520                                       section_size_type view_size)
2521 {
2522   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2523   // .word 0x6666; rex64; call __tls_get_addr
2524   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2525
2526   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2527   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2528
2529   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2530                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2531   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2532                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2533
2534   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2535
2536   value -= tls_segment->memsz();
2537   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2538
2539   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2540   // We can skip it.
2541   this->skip_call_tls_get_addr_ = true;
2542 }
2543
2544 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2545
2546 inline void
2547 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2548     const Relocate_info<64, false>* relinfo,
2549     size_t relnum,
2550     Output_segment*,
2551     const elfcpp::Rela<64, false>& rela,
2552     unsigned int r_type,
2553     elfcpp::Elf_types<64>::Elf_Addr value,
2554     unsigned char* view,
2555     elfcpp::Elf_types<64>::Elf_Addr address,
2556     section_size_type view_size)
2557 {
2558   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2559     {
2560       // leaq foo@tlsdesc(%rip), %rax
2561       // ==> movq foo@gottpoff(%rip), %rax
2562       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2563       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2564       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2565                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2566       view[-2] = 0x8b;
2567       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2568       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2569     }
2570   else
2571     {
2572       // call *foo@tlscall(%rax)
2573       // ==> nop; nop
2574       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2575       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2576       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2577                      view[0] == 0xff && view[1] == 0x10);
2578       view[0] = 0x66;
2579       view[1] = 0x90;
2580     }
2581 }
2582
2583 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2584
2585 inline void
2586 Target_x86_64::Relocate::tls_desc_gd_to_le(
2587     const Relocate_info<64, false>* relinfo,
2588     size_t relnum,
2589     Output_segment* tls_segment,
2590     const elfcpp::Rela<64, false>& rela,
2591     unsigned int r_type,
2592     elfcpp::Elf_types<64>::Elf_Addr value,
2593     unsigned char* view,
2594     section_size_type view_size)
2595 {
2596   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2597     {
2598       // leaq foo@tlsdesc(%rip), %rax
2599       // ==> movq foo@tpoff, %rax
2600       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2601       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2602       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2603                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2604       view[-2] = 0xc7;
2605       view[-1] = 0xc0;
2606       value -= tls_segment->memsz();
2607       Relocate_functions<64, false>::rela32(view, value, 0);
2608     }
2609   else
2610     {
2611       // call *foo@tlscall(%rax)
2612       // ==> nop; nop
2613       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2614       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2615       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2616                      view[0] == 0xff && view[1] == 0x10);
2617       view[0] = 0x66;
2618       view[1] = 0x90;
2619     }
2620 }
2621
2622 inline void
2623 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2624                                       size_t relnum,
2625                                       Output_segment*,
2626                                       const elfcpp::Rela<64, false>& rela,
2627                                       unsigned int,
2628                                       elfcpp::Elf_types<64>::Elf_Addr,
2629                                       unsigned char* view,
2630                                       section_size_type view_size)
2631 {
2632   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2633   // ... leq foo@dtpoff(%rax),%reg
2634   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2635
2636   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2637   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2638
2639   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2640                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2641
2642   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2643
2644   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2645
2646   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2647   // We can skip it.
2648   this->skip_call_tls_get_addr_ = true;
2649 }
2650
2651 // Do a relocation in which we convert a TLS Initial-Exec to a
2652 // Local-Exec.
2653
2654 inline void
2655 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2656                                       size_t relnum,
2657                                       Output_segment* tls_segment,
2658                                       const elfcpp::Rela<64, false>& rela,
2659                                       unsigned int,
2660                                       elfcpp::Elf_types<64>::Elf_Addr value,
2661                                       unsigned char* view,
2662                                       section_size_type view_size)
2663 {
2664   // We need to examine the opcodes to figure out which instruction we
2665   // are looking at.
2666
2667   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2668   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2669
2670   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2671   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2672
2673   unsigned char op1 = view[-3];
2674   unsigned char op2 = view[-2];
2675   unsigned char op3 = view[-1];
2676   unsigned char reg = op3 >> 3;
2677
2678   if (op2 == 0x8b)
2679     {
2680       // movq
2681       if (op1 == 0x4c)
2682         view[-3] = 0x49;
2683       view[-2] = 0xc7;
2684       view[-1] = 0xc0 | reg;
2685     }
2686   else if (reg == 4)
2687     {
2688       // Special handling for %rsp.
2689       if (op1 == 0x4c)
2690         view[-3] = 0x49;
2691       view[-2] = 0x81;
2692       view[-1] = 0xc0 | reg;
2693     }
2694   else
2695     {
2696       // addq
2697       if (op1 == 0x4c)
2698         view[-3] = 0x4d;
2699       view[-2] = 0x8d;
2700       view[-1] = 0x80 | reg | (reg << 3);
2701     }
2702
2703   value -= tls_segment->memsz();
2704   Relocate_functions<64, false>::rela32(view, value, 0);
2705 }
2706
2707 // Relocate section data.
2708
2709 void
2710 Target_x86_64::relocate_section(
2711     const Relocate_info<64, false>* relinfo,
2712     unsigned int sh_type,
2713     const unsigned char* prelocs,
2714     size_t reloc_count,
2715     Output_section* output_section,
2716     bool needs_special_offset_handling,
2717     unsigned char* view,
2718     elfcpp::Elf_types<64>::Elf_Addr address,
2719     section_size_type view_size,
2720     const Reloc_symbol_changes* reloc_symbol_changes)
2721 {
2722   gold_assert(sh_type == elfcpp::SHT_RELA);
2723
2724   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2725                          Target_x86_64::Relocate>(
2726     relinfo,
2727     this,
2728     prelocs,
2729     reloc_count,
2730     output_section,
2731     needs_special_offset_handling,
2732     view,
2733     address,
2734     view_size,
2735     reloc_symbol_changes);
2736 }
2737
2738 // Return the size of a relocation while scanning during a relocatable
2739 // link.
2740
2741 unsigned int
2742 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2743     unsigned int r_type,
2744     Relobj* object)
2745 {
2746   switch (r_type)
2747     {
2748     case elfcpp::R_X86_64_NONE:
2749     case elfcpp::R_X86_64_GNU_VTINHERIT:
2750     case elfcpp::R_X86_64_GNU_VTENTRY:
2751     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2752     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2753     case elfcpp::R_X86_64_TLSDESC_CALL:
2754     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2755     case elfcpp::R_X86_64_DTPOFF32:
2756     case elfcpp::R_X86_64_DTPOFF64:
2757     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2758     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2759       return 0;
2760
2761     case elfcpp::R_X86_64_64:
2762     case elfcpp::R_X86_64_PC64:
2763     case elfcpp::R_X86_64_GOTOFF64:
2764     case elfcpp::R_X86_64_GOTPC64:
2765     case elfcpp::R_X86_64_PLTOFF64:
2766     case elfcpp::R_X86_64_GOT64:
2767     case elfcpp::R_X86_64_GOTPCREL64:
2768     case elfcpp::R_X86_64_GOTPCREL:
2769     case elfcpp::R_X86_64_GOTPLT64:
2770       return 8;
2771
2772     case elfcpp::R_X86_64_32:
2773     case elfcpp::R_X86_64_32S:
2774     case elfcpp::R_X86_64_PC32:
2775     case elfcpp::R_X86_64_PLT32:
2776     case elfcpp::R_X86_64_GOTPC32:
2777     case elfcpp::R_X86_64_GOT32:
2778       return 4;
2779
2780     case elfcpp::R_X86_64_16:
2781     case elfcpp::R_X86_64_PC16:
2782       return 2;
2783
2784     case elfcpp::R_X86_64_8:
2785     case elfcpp::R_X86_64_PC8:
2786       return 1;
2787
2788     case elfcpp::R_X86_64_COPY:
2789     case elfcpp::R_X86_64_GLOB_DAT:
2790     case elfcpp::R_X86_64_JUMP_SLOT:
2791     case elfcpp::R_X86_64_RELATIVE:
2792       // These are outstanding tls relocs, which are unexpected when linking
2793     case elfcpp::R_X86_64_TPOFF64:
2794     case elfcpp::R_X86_64_DTPMOD64:
2795     case elfcpp::R_X86_64_TLSDESC:
2796       object->error(_("unexpected reloc %u in object file"), r_type);
2797       return 0;
2798
2799     case elfcpp::R_X86_64_SIZE32:
2800     case elfcpp::R_X86_64_SIZE64:
2801     default:
2802       object->error(_("unsupported reloc %u against local symbol"), r_type);
2803       return 0;
2804     }
2805 }
2806
2807 // Scan the relocs during a relocatable link.
2808
2809 void
2810 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
2811                                        Layout* layout,
2812                                        Sized_relobj<64, false>* object,
2813                                        unsigned int data_shndx,
2814                                        unsigned int sh_type,
2815                                        const unsigned char* prelocs,
2816                                        size_t reloc_count,
2817                                        Output_section* output_section,
2818                                        bool needs_special_offset_handling,
2819                                        size_t local_symbol_count,
2820                                        const unsigned char* plocal_symbols,
2821                                        Relocatable_relocs* rr)
2822 {
2823   gold_assert(sh_type == elfcpp::SHT_RELA);
2824
2825   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2826     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2827
2828   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2829       Scan_relocatable_relocs>(
2830     symtab,
2831     layout,
2832     object,
2833     data_shndx,
2834     prelocs,
2835     reloc_count,
2836     output_section,
2837     needs_special_offset_handling,
2838     local_symbol_count,
2839     plocal_symbols,
2840     rr);
2841 }
2842
2843 // Relocate a section during a relocatable link.
2844
2845 void
2846 Target_x86_64::relocate_for_relocatable(
2847     const Relocate_info<64, false>* relinfo,
2848     unsigned int sh_type,
2849     const unsigned char* prelocs,
2850     size_t reloc_count,
2851     Output_section* output_section,
2852     off_t offset_in_output_section,
2853     const Relocatable_relocs* rr,
2854     unsigned char* view,
2855     elfcpp::Elf_types<64>::Elf_Addr view_address,
2856     section_size_type view_size,
2857     unsigned char* reloc_view,
2858     section_size_type reloc_view_size)
2859 {
2860   gold_assert(sh_type == elfcpp::SHT_RELA);
2861
2862   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2863     relinfo,
2864     prelocs,
2865     reloc_count,
2866     output_section,
2867     offset_in_output_section,
2868     rr,
2869     view,
2870     view_address,
2871     view_size,
2872     reloc_view,
2873     reloc_view_size);
2874 }
2875
2876 // Return the value to use for a dynamic which requires special
2877 // treatment.  This is how we support equality comparisons of function
2878 // pointers across shared library boundaries, as described in the
2879 // processor specific ABI supplement.
2880
2881 uint64_t
2882 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2883 {
2884   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2885   return this->plt_section()->address() + gsym->plt_offset();
2886 }
2887
2888 // Return a string used to fill a code section with nops to take up
2889 // the specified length.
2890
2891 std::string
2892 Target_x86_64::do_code_fill(section_size_type length) const
2893 {
2894   if (length >= 16)
2895     {
2896       // Build a jmpq instruction to skip over the bytes.
2897       unsigned char jmp[5];
2898       jmp[0] = 0xe9;
2899       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2900       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2901               + std::string(length - 5, '\0'));
2902     }
2903
2904   // Nop sequences of various lengths.
2905   const char nop1[1] = { 0x90 };                   // nop
2906   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2907   const char nop3[3] = { 0x0f, 0x1f, 0x00 };       // nop (%rax)
2908   const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00};  // nop 0(%rax)
2909   const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00,   // nop 0(%rax,%rax,1)
2910                          0x00 };
2911   const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44,   // nopw 0(%rax,%rax,1)
2912                          0x00, 0x00 };
2913   const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00,   // nopl 0L(%rax)
2914                          0x00, 0x00, 0x00 };
2915   const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00,   // nopl 0L(%rax,%rax,1)
2916                          0x00, 0x00, 0x00, 0x00 };
2917   const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84,   // nopw 0L(%rax,%rax,1)
2918                          0x00, 0x00, 0x00, 0x00,
2919                          0x00 };
2920   const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
2921                            0x84, 0x00, 0x00, 0x00,
2922                            0x00, 0x00 };
2923   const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
2924                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2925                            0x00, 0x00, 0x00 };
2926   const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
2927                            0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
2928                            0x00, 0x00, 0x00, 0x00 };
2929   const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2930                            0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
2931                            0x00, 0x00, 0x00, 0x00,
2932                            0x00 };
2933   const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2934                            0x66, 0x2e, 0x0f, 0x1f, // data16
2935                            0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2936                            0x00, 0x00 };
2937   const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2938                            0x66, 0x66, 0x2e, 0x0f, // data16; data16
2939                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2940                            0x00, 0x00, 0x00 };
2941
2942   const char* nops[16] = {
2943     NULL,
2944     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2945     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2946   };
2947
2948   return std::string(nops[length], length);
2949 }
2950
2951 // Return the addend to use for a target specific relocation.  The
2952 // only target specific relocation is R_X86_64_TLSDESC for a local
2953 // symbol.  We want to set the addend is the offset of the local
2954 // symbol in the TLS segment.
2955
2956 uint64_t
2957 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
2958                                uint64_t) const
2959 {
2960   gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
2961   uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
2962   gold_assert(intarg < this->tlsdesc_reloc_info_.size());
2963   const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
2964   const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
2965   gold_assert(psymval->is_tls_symbol());
2966   // The value of a TLS symbol is the offset in the TLS segment.
2967   return psymval->value(ti.object, 0);
2968 }
2969
2970 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2971 // compiled with -fstack-split.  The function calls non-stack-split
2972 // code.  We have to change the function so that it always ensures
2973 // that it has enough stack space to run some random function.
2974
2975 void
2976 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
2977                                   section_offset_type fnoffset,
2978                                   section_size_type fnsize,
2979                                   unsigned char* view,
2980                                   section_size_type view_size,
2981                                   std::string* from,
2982                                   std::string* to) const
2983 {
2984   // The function starts with a comparison of the stack pointer and a
2985   // field in the TCB.  This is followed by a jump.
2986
2987   // cmp %fs:NN,%rsp
2988   if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
2989       && fnsize > 9)
2990     {
2991       // We will call __morestack if the carry flag is set after this
2992       // comparison.  We turn the comparison into an stc instruction
2993       // and some nops.
2994       view[fnoffset] = '\xf9';
2995       this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
2996     }
2997   // lea NN(%rsp),%r10
2998   // lea NN(%rsp),%r11
2999   else if ((this->match_view(view, view_size, fnoffset,
3000                              "\x4c\x8d\x94\x24", 4)
3001             || this->match_view(view, view_size, fnoffset,
3002                                 "\x4c\x8d\x9c\x24", 4))
3003            && fnsize > 8)
3004     {
3005       // This is loading an offset from the stack pointer for a
3006       // comparison.  The offset is negative, so we decrease the
3007       // offset by the amount of space we need for the stack.  This
3008       // means we will avoid calling __morestack if there happens to
3009       // be plenty of space on the stack already.
3010       unsigned char* pval = view + fnoffset + 4;
3011       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
3012       val -= parameters->options().split_stack_adjust_size();
3013       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
3014     }
3015   else
3016     {
3017       if (!object->has_no_split_stack())
3018         object->error(_("failed to match split-stack sequence at "
3019                         "section %u offset %0zx"),
3020                       shndx, static_cast<size_t>(fnoffset));
3021       return;
3022     }
3023
3024   // We have to change the function so that it calls
3025   // __morestack_non_split instead of __morestack.  The former will
3026   // allocate additional stack space.
3027   *from = "__morestack";
3028   *to = "__morestack_non_split";
3029 }
3030
3031 // The selector for x86_64 object files.
3032
3033 class Target_selector_x86_64 : public Target_selector_freebsd
3034 {
3035 public:
3036   Target_selector_x86_64()
3037     : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
3038                               "elf64-x86-64-freebsd")
3039   { }
3040
3041   Target*
3042   do_instantiate_target()
3043   { return new Target_x86_64(); }
3044
3045 };
3046
3047 Target_selector_x86_64 target_selector_x86_64;
3048
3049 } // End anonymous namespace.