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()
 201   {
 202     gold_assert(this->got_ != NULL);
 203     return this->got_->data_size();
 204   }
 205
 206   // Add a new reloc argument, returning the index in the vector.
 207   size_t
 208   add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym)
 209   {
 210     this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
 211     return this->tlsdesc_reloc_info_.size() - 1;
 212   }
 213
 214  private:
 215   // The class which scans relocations.
 216   class Scan
 217   {
 218   public:
 219     Scan()
 220       : issued_non_pic_error_(false)
 221     { }
 222
 223     inline void
 224     local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 225           Sized_relobj<64, false>* object,
 226           unsigned int data_shndx,
 227           Output_section* output_section,
 228           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 229           const elfcpp::Sym<64, false>& lsym);
 230
 231     inline void
 232     global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 233            Sized_relobj<64, false>* object,
 234            unsigned int data_shndx,
 235            Output_section* output_section,
 236            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 237            Symbol* gsym);
 238
 239     inline bool
 240     local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 241                                         Target_x86_64* target,
 242                                         Sized_relobj<64, false>* object,
 243                                         unsigned int data_shndx,
 244                                         Output_section* output_section,
 245                                         const elfcpp::Rela<64, false>& reloc,
 246                                         unsigned int r_type,
 247                                         const elfcpp::Sym<64, false>& lsym);
 248
 249     inline bool
 250     global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 251                                          Target_x86_64* target,
 252                                          Sized_relobj<64, false>* object,
 253                                          unsigned int data_shndx,
 254                                          Output_section* output_section,
 255                                          const elfcpp::Rela<64, false>& reloc,
 256                                          unsigned int r_type,
 257                                          Symbol* gsym);
 258
 259   private:
 260     static void
 261     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 262
 263     static void
 264     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 265                              Symbol*);
 266
 267     void
 268     check_non_pic(Relobj*, unsigned int r_type);
 269
 270     inline bool
 271     possible_function_pointer_reloc(unsigned int r_type);
 272
 273     // Whether we have issued an error about a non-PIC compilation.
 274     bool issued_non_pic_error_;
 275   };
 276
 277   // The class which implements relocation.
 278   class Relocate
 279   {
 280    public:
 281     Relocate()
 282       : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
 283     { }
 284
 285     ~Relocate()
 286     {
 287       if (this->skip_call_tls_get_addr_)
 288         {
 289           // FIXME: This needs to specify the location somehow.
 290           gold_error(_("missing expected TLS relocation"));
 291         }
 292     }
 293
 294     // Do a relocation.  Return false if the caller should not issue
 295     // any warnings about this relocation.
 296     inline bool
 297     relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
 298              size_t relnum, const elfcpp::Rela<64, false>&,
 299              unsigned int r_type, const Sized_symbol<64>*,
 300              const Symbol_value<64>*,
 301              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 302              section_size_type);
 303
 304    private:
 305     // Do a TLS relocation.
 306     inline void
 307     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 308                  size_t relnum, const elfcpp::Rela<64, false>&,
 309                  unsigned int r_type, const Sized_symbol<64>*,
 310                  const Symbol_value<64>*,
 311                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 312                  section_size_type);
 313
 314     // Do a TLS General-Dynamic to Initial-Exec transition.
 315     inline void
 316     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 317                  Output_segment* tls_segment,
 318                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 319                  elfcpp::Elf_types<64>::Elf_Addr value,
 320                  unsigned char* view,
 321                  elfcpp::Elf_types<64>::Elf_Addr,
 322                  section_size_type view_size);
 323
 324     // Do a TLS General-Dynamic to Local-Exec transition.
 325     inline void
 326     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 327                  Output_segment* tls_segment,
 328                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 329                  elfcpp::Elf_types<64>::Elf_Addr value,
 330                  unsigned char* view,
 331                  section_size_type view_size);
 332
 333     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 334     inline void
 335     tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 336                       Output_segment* tls_segment,
 337                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 338                       elfcpp::Elf_types<64>::Elf_Addr value,
 339                       unsigned char* view,
 340                       elfcpp::Elf_types<64>::Elf_Addr,
 341                       section_size_type view_size);
 342
 343     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 344     inline void
 345     tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 346                       Output_segment* tls_segment,
 347                       const elfcpp::Rela<64, false>&, unsigned int r_type,
 348                       elfcpp::Elf_types<64>::Elf_Addr value,
 349                       unsigned char* view,
 350                       section_size_type view_size);
 351
 352     // Do a TLS Local-Dynamic to Local-Exec transition.
 353     inline void
 354     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 355                  Output_segment* tls_segment,
 356                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 357                  elfcpp::Elf_types<64>::Elf_Addr value,
 358                  unsigned char* view,
 359                  section_size_type view_size);
 360
 361     // Do a TLS Initial-Exec to Local-Exec transition.
 362     static inline void
 363     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 364                  Output_segment* tls_segment,
 365                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 366                  elfcpp::Elf_types<64>::Elf_Addr value,
 367                  unsigned char* view,
 368                  section_size_type view_size);
 369
 370     // This is set if we should skip the next reloc, which should be a
 371     // PLT32 reloc against ___tls_get_addr.
 372     bool skip_call_tls_get_addr_;
 373
 374     // This is set if we see a relocation which could load the address
 375     // of the TLS block.  Whether we see such a relocation determines
 376     // how we handle the R_X86_64_DTPOFF32 relocation, which is used
 377     // in debugging sections.
 378     bool saw_tls_block_reloc_;
 379   };
 380
 381   // A class which returns the size required for a relocation type,
 382   // used while scanning relocs during a relocatable link.
 383   class Relocatable_size_for_reloc
 384   {
 385    public:
 386     unsigned int
 387     get_size_for_reloc(unsigned int, Relobj*);
 388   };
 389
 390   // Adjust TLS relocation type based on the options and whether this
 391   // is a local symbol.
 392   static tls::Tls_optimization
 393   optimize_tls_reloc(bool is_final, int r_type);
 394
 395   // Get the GOT section, creating it if necessary.
 396   Output_data_got<64, false>*
 397   got_section(Symbol_table*, Layout*);
 398
 399   // Get the GOT PLT section.
 400   Output_data_space*
 401   got_plt_section() const
 402   {
 403     gold_assert(this->got_plt_ != NULL);
 404     return this->got_plt_;
 405   }
 406
 407   // Get the GOT section for TLSDESC entries.
 408   Output_data_got<64, false>*
 409   got_tlsdesc_section() const
 410   {
 411     gold_assert(this->got_tlsdesc_ != NULL);
 412     return this->got_tlsdesc_;
 413   }
 414
 415   // Create the PLT section.
 416   void
 417   make_plt_section(Symbol_table* symtab, Layout* layout);
 418
 419   // Create a PLT entry for a global symbol.
 420   void
 421   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 422
 423   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 424   void
 425   define_tls_base_symbol(Symbol_table*, Layout*);
 426
 427   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 428   void
 429   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 430
 431   // Create a GOT entry for the TLS module index.
 432   unsigned int
 433   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 434                       Sized_relobj<64, false>* object);
 435
 436   // Get the PLT section.
 437   Output_data_plt_x86_64*
 438   plt_section() const
 439   {
 440     gold_assert(this->plt_ != NULL);
 441     return this->plt_;
 442   }
 443
 444   // Get the dynamic reloc section, creating it if necessary.
 445   Reloc_section*
 446   rela_dyn_section(Layout*);
 447
 448   // Get the section to use for TLSDESC relocations.
 449   Reloc_section*
 450   rela_tlsdesc_section(Layout*) const;
 451
 452   // Add a potential copy relocation.
 453   void
 454   copy_reloc(Symbol_table* symtab, Layout* layout,
 455              Sized_relobj<64, false>* object,
 456              unsigned int shndx, Output_section* output_section,
 457              Symbol* sym, const elfcpp::Rela<64, false>& reloc)
 458   {
 459     this->copy_relocs_.copy_reloc(symtab, layout,
 460                                   symtab->get_sized_symbol<64>(sym),
 461                                   object, shndx, output_section,
 462                                   reloc, this->rela_dyn_section(layout));
 463   }
 464
 465   // Information about this specific target which we pass to the
 466   // general Target structure.
 467   static const Target::Target_info x86_64_info;
 468
 469   enum Got_type
 470   {
 471     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 472     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 473     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 474     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 475   };
 476
 477   // This type is used as the argument to the target specific
 478   // relocation routines.  The only target specific reloc is
 479   // R_X86_64_TLSDESC against a local symbol.
 480   struct Tlsdesc_info
 481   {
 482     Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym)
 483       : object(a_object), r_sym(a_r_sym)
 484     { }
 485
 486     // The object in which the local symbol is defined.
 487     Sized_relobj<64, false>* object;
 488     // The local symbol index in the object.
 489     unsigned int r_sym;
 490   };
 491
 492   // The GOT section.
 493   Output_data_got<64, false>* got_;
 494   // The PLT section.
 495   Output_data_plt_x86_64* plt_;
 496   // The GOT PLT section.
 497   Output_data_space* got_plt_;
 498   // The GOT section for TLSDESC relocations.
 499   Output_data_got<64, false>* got_tlsdesc_;
 500   // The _GLOBAL_OFFSET_TABLE_ symbol.
 501   Symbol* global_offset_table_;
 502   // The dynamic reloc section.
 503   Reloc_section* rela_dyn_;
 504   // Relocs saved to avoid a COPY reloc.
 505   Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
 506   // Space for variables copied with a COPY reloc.
 507   Output_data_space* dynbss_;
 508   // Offset of the GOT entry for the TLS module index.
 509   unsigned int got_mod_index_offset_;
 510   // We handle R_X86_64_TLSDESC against a local symbol as a target
 511   // specific relocation.  Here we store the object and local symbol
 512   // index for the relocation.
 513   std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
 514   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 515   bool tls_base_symbol_defined_;
 516 };
 517
 518 const Target::Target_info Target_x86_64::x86_64_info =
 519 {
 520   64,                   // size
 521   false,                // is_big_endian
 522   elfcpp::EM_X86_64,    // machine_code
 523   false,                // has_make_symbol
 524   false,                // has_resolve
 525   true,                 // has_code_fill
 526   true,                 // is_default_stack_executable
 527   '\0',                 // wrap_char
 528   "/lib/ld64.so.1",     // program interpreter
 529   0x400000,             // default_text_segment_address
 530   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 531   0x1000,               // common_pagesize (overridable by -z common-page-size)
 532   elfcpp::SHN_UNDEF,    // small_common_shndx
 533   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 534   0,                    // small_common_section_flags
 535   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 536   NULL,                 // attributes_section
 537   NULL                  // attributes_vendor
 538 };
 539
 540 // This is called when a new output section is created.  This is where
 541 // we handle the SHF_X86_64_LARGE.
 542
 543 void
 544 Target_x86_64::do_new_output_section(Output_section *os) const
 545 {
 546   if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
 547     os->set_is_large_section();
 548 }
 549
 550 // Get the GOT section, creating it if necessary.
 551
 552 Output_data_got<64, false>*
 553 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 554 {
 555   if (this->got_ == NULL)
 556     {
 557       gold_assert(symtab != NULL && layout != NULL);
 558
 559       this->got_ = new Output_data_got<64, false>();
 560
 561       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 562                                       (elfcpp::SHF_ALLOC
 563                                        | elfcpp::SHF_WRITE),
 564                                       this->got_, false, true, true, false);
 565
 566       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 567       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 568                                       (elfcpp::SHF_ALLOC
 569                                        | elfcpp::SHF_WRITE),
 570                                       this->got_plt_, false, false, false,
 571                                       true);
 572
 573       // The first three entries are reserved.
 574       this->got_plt_->set_current_data_size(3 * 8);
 575
 576       // Those bytes can go into the relro segment.
 577       layout->increase_relro(3 * 8);
 578
 579       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 580       this->global_offset_table_ =
 581         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 582                                       Symbol_table::PREDEFINED,
 583                                       this->got_plt_,
 584                                       0, 0, elfcpp::STT_OBJECT,
 585                                       elfcpp::STB_LOCAL,
 586                                       elfcpp::STV_HIDDEN, 0,
 587                                       false, false);
 588
 589       // If there are any TLSDESC relocations, they get GOT entries in
 590       // .got.plt after the jump slot entries.
 591       this->got_tlsdesc_ = new Output_data_got<64, false>();
 592       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 593                                       (elfcpp::SHF_ALLOC
 594                                        | elfcpp::SHF_WRITE),
 595                                       this->got_tlsdesc_, false, false, false,
 596                                       true);
 597     }
 598
 599   return this->got_;
 600 }
 601
 602 // Get the dynamic reloc section, creating it if necessary.
 603
 604 Target_x86_64::Reloc_section*
 605 Target_x86_64::rela_dyn_section(Layout* layout)
 606 {
 607   if (this->rela_dyn_ == NULL)
 608     {
 609       gold_assert(layout != NULL);
 610       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 611       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 612                                       elfcpp::SHF_ALLOC, this->rela_dyn_, true,
 613                                       false, false, false);
 614     }
 615   return this->rela_dyn_;
 616 }
 617
 618 // A class to handle the PLT data.
 619
 620 class Output_data_plt_x86_64 : public Output_section_data
 621 {
 622  public:
 623   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 624
 625   Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*,
 626                          Output_data_space*);
 627
 628   // Add an entry to the PLT.
 629   void
 630   add_entry(Symbol* gsym);
 631
 632   // Add the reserved TLSDESC_PLT entry to the PLT.
 633   void
 634   reserve_tlsdesc_entry(unsigned int got_offset)
 635   { this->tlsdesc_got_offset_ = got_offset; }
 636
 637   // Return true if a TLSDESC_PLT entry has been reserved.
 638   bool
 639   has_tlsdesc_entry() const
 640   { return this->tlsdesc_got_offset_ != -1U; }
 641
 642   // Return the GOT offset for the reserved TLSDESC_PLT entry.
 643   unsigned int
 644   get_tlsdesc_got_offset() const
 645   { return this->tlsdesc_got_offset_; }
 646
 647   // Return the offset of the reserved TLSDESC_PLT entry.
 648   unsigned int
 649   get_tlsdesc_plt_offset() const
 650   { return (this->count_ + 1) * plt_entry_size; }
 651
 652   // Return the .rela.plt section data.
 653   const Reloc_section*
 654   rela_plt() const
 655   { return this->rel_; }
 656
 657   // Return where the TLSDESC relocations should go.
 658   Reloc_section*
 659   rela_tlsdesc(Layout*);
 660
 661  protected:
 662   void
 663   do_adjust_output_section(Output_section* os);
 664
 665   // Write to a map file.
 666   void
 667   do_print_to_mapfile(Mapfile* mapfile) const
 668   { mapfile->print_output_data(this, _("** PLT")); }
 669
 670  private:
 671   // The size of an entry in the PLT.
 672   static const int plt_entry_size = 16;
 673
 674   // The first entry in the PLT.
 675   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 676   // procedure linkage table for both programs and shared objects."
 677   static unsigned char first_plt_entry[plt_entry_size];
 678
 679   // Other entries in the PLT for an executable.
 680   static unsigned char plt_entry[plt_entry_size];
 681
 682   // The reserved TLSDESC entry in the PLT for an executable.
 683   static unsigned char tlsdesc_plt_entry[plt_entry_size];
 684
 685   // Set the final size.
 686   void
 687   set_final_data_size();
 688
 689   // Write out the PLT data.
 690   void
 691   do_write(Output_file*);
 692
 693   // The reloc section.
 694   Reloc_section* rel_;
 695   // The TLSDESC relocs, if necessary.  These must follow the regular
 696   // PLT relocs.
 697   Reloc_section* tlsdesc_rel_;
 698   // The .got section.
 699   Output_data_got<64, false>* got_;
 700   // The .got.plt section.
 701   Output_data_space* got_plt_;
 702   // The number of PLT entries.
 703   unsigned int count_;
 704   // Offset of the reserved TLSDESC_GOT entry when needed.
 705   unsigned int tlsdesc_got_offset_;
 706 };
 707
 708 // Create the PLT section.  The ordinary .got section is an argument,
 709 // since we need to refer to the start.  We also create our own .got
 710 // section just for PLT entries.
 711
 712 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 713                                                Output_data_got<64, false>* got,
 714                                                Output_data_space* got_plt)
 715   : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
 716     count_(0), tlsdesc_got_offset_(-1U)
 717 {
 718   this->rel_ = new Reloc_section(false);
 719   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 720                                   elfcpp::SHF_ALLOC, this->rel_, true,
 721                                   false, false, false);
 722 }
 723
 724 void
 725 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 726 {
 727   os->set_entsize(plt_entry_size);
 728 }
 729
 730 // Add an entry to the PLT.
 731
 732 void
 733 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 734 {
 735   gold_assert(!gsym->has_plt_offset());
 736
 737   // Note that when setting the PLT offset we skip the initial
 738   // reserved PLT entry.
 739   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 740
 741   ++this->count_;
 742
 743   section_offset_type got_offset = this->got_plt_->current_data_size();
 744
 745   // Every PLT entry needs a GOT entry which points back to the PLT
 746   // entry (this will be changed by the dynamic linker, normally
 747   // lazily when the function is called).
 748   this->got_plt_->set_current_data_size(got_offset + 8);
 749
 750   // Every PLT entry needs a reloc.
 751   gsym->set_needs_dynsym_entry();
 752   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 753                          got_offset, 0);
 754
 755   // Note that we don't need to save the symbol.  The contents of the
 756   // PLT are independent of which symbols are used.  The symbols only
 757   // appear in the relocations.
 758 }
 759
 760 // Return where the TLSDESC relocations should go, creating it if
 761 // necessary.  These follow the JUMP_SLOT relocations.
 762
 763 Output_data_plt_x86_64::Reloc_section*
 764 Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
 765 {
 766   if (this->tlsdesc_rel_ == NULL)
 767     {
 768       this->tlsdesc_rel_ = new Reloc_section(false);
 769       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 770                                       elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
 771                                       true, false, false, false);
 772       gold_assert(this->tlsdesc_rel_->output_section() ==
 773                   this->rel_->output_section());
 774     }
 775   return this->tlsdesc_rel_;
 776 }
 777
 778 // Set the final size.
 779 void
 780 Output_data_plt_x86_64::set_final_data_size()
 781 {
 782   unsigned int count = this->count_;
 783   if (this->has_tlsdesc_entry())
 784     ++count;
 785   this->set_data_size((count + 1) * plt_entry_size);
 786 }
 787
 788 // The first entry in the PLT for an executable.
 789
 790 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 791 {
 792   // From AMD64 ABI Draft 0.98, page 76
 793   0xff, 0x35,   // pushq contents of memory address
 794   0, 0, 0, 0,   // replaced with address of .got + 8
 795   0xff, 0x25,   // jmp indirect
 796   0, 0, 0, 0,   // replaced with address of .got + 16
 797   0x90, 0x90, 0x90, 0x90   // noop (x4)
 798 };
 799
 800 // Subsequent entries in the PLT for an executable.
 801
 802 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 803 {
 804   // From AMD64 ABI Draft 0.98, page 76
 805   0xff, 0x25,   // jmpq indirect
 806   0, 0, 0, 0,   // replaced with address of symbol in .got
 807   0x68,         // pushq immediate
 808   0, 0, 0, 0,   // replaced with offset into relocation table
 809   0xe9,         // jmpq relative
 810   0, 0, 0, 0    // replaced with offset to start of .plt
 811 };
 812
 813 // The reserved TLSDESC entry in the PLT for an executable.
 814
 815 unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
 816 {
 817   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
 818   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
 819   0xff, 0x35,   // pushq x(%rip)
 820   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
 821   0xff, 0x25,   // jmpq *y(%rip)
 822   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
 823   0x0f, 0x1f,   // nop
 824   0x40, 0
 825 };
 826
 827 // Write out the PLT.  This uses the hand-coded instructions above,
 828 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 829
 830 void
 831 Output_data_plt_x86_64::do_write(Output_file* of)
 832 {
 833   const off_t offset = this->offset();
 834   const section_size_type oview_size =
 835     convert_to_section_size_type(this->data_size());
 836   unsigned char* const oview = of->get_output_view(offset, oview_size);
 837
 838   const off_t got_file_offset = this->got_plt_->offset();
 839   const section_size_type got_size =
 840     convert_to_section_size_type(this->got_plt_->data_size());
 841   unsigned char* const got_view = of->get_output_view(got_file_offset,
 842                                                       got_size);
 843
 844   unsigned char* pov = oview;
 845
 846   // The base address of the .plt section.
 847   elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
 848   // The base address of the .got section.
 849   elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
 850   // The base address of the PLT portion of the .got section,
 851   // which is where the GOT pointer will point, and where the
 852   // three reserved GOT entries are located.
 853   elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
 854
 855   memcpy(pov, first_plt_entry, plt_entry_size);
 856   // We do a jmp relative to the PC at the end of this instruction.
 857   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 858                                               (got_address + 8
 859                                                - (plt_address + 6)));
 860   elfcpp::Swap<32, false>::writeval(pov + 8,
 861                                     (got_address + 16
 862                                      - (plt_address + 12)));
 863   pov += plt_entry_size;
 864
 865   unsigned char* got_pov = got_view;
 866
 867   memset(got_pov, 0, 24);
 868   got_pov += 24;
 869
 870   unsigned int plt_offset = plt_entry_size;
 871   unsigned int got_offset = 24;
 872   const unsigned int count = this->count_;
 873   for (unsigned int plt_index = 0;
 874        plt_index < count;
 875        ++plt_index,
 876          pov += plt_entry_size,
 877          got_pov += 8,
 878          plt_offset += plt_entry_size,
 879          got_offset += 8)
 880     {
 881       // Set and adjust the PLT entry itself.
 882       memcpy(pov, plt_entry, plt_entry_size);
 883       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 884                                                   (got_address + got_offset
 885                                                    - (plt_address + plt_offset
 886                                                       + 6)));
 887
 888       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 889       elfcpp::Swap<32, false>::writeval(pov + 12,
 890                                         - (plt_offset + plt_entry_size));
 891
 892       // Set the entry in the GOT.
 893       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 894     }
 895
 896   if (this->has_tlsdesc_entry())
 897     {
 898       // Set and adjust the reserved TLSDESC PLT entry.
 899       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
 900       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
 901       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 902                                                   (got_address + 8
 903                                                    - (plt_address + plt_offset
 904                                                       + 6)));
 905       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
 906                                                   (got_base
 907                                                    + tlsdesc_got_offset
 908                                                    - (plt_address + plt_offset
 909                                                       + 12)));
 910       pov += plt_entry_size;
 911     }
 912
 913   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 914   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 915
 916   of->write_output_view(offset, oview_size, oview);
 917   of->write_output_view(got_file_offset, got_size, got_view);
 918 }
 919
 920 // Create the PLT section.
 921
 922 void
 923 Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
 924 {
 925   if (this->plt_ == NULL)
 926     {
 927       // Create the GOT sections first.
 928       this->got_section(symtab, layout);
 929
 930       this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
 931                                               this->got_plt_);
 932       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 933                                       (elfcpp::SHF_ALLOC
 934                                        | elfcpp::SHF_EXECINSTR),
 935                                       this->plt_, false, false, false, false);
 936     }
 937 }
 938
 939 // Return the section for TLSDESC relocations.
 940
 941 Target_x86_64::Reloc_section*
 942 Target_x86_64::rela_tlsdesc_section(Layout* layout) const
 943 {
 944   return this->plt_section()->rela_tlsdesc(layout);
 945 }
 946
 947 // Create a PLT entry for a global symbol.
 948
 949 void
 950 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 951                               Symbol* gsym)
 952 {
 953   if (gsym->has_plt_offset())
 954     return;
 955
 956   if (this->plt_ == NULL)
 957     this->make_plt_section(symtab, layout);
 958
 959   this->plt_->add_entry(gsym);
 960 }
 961
 962 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 963
 964 void
 965 Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
 966 {
 967   if (this->tls_base_symbol_defined_)
 968     return;
 969
 970   Output_segment* tls_segment = layout->tls_segment();
 971   if (tls_segment != NULL)
 972     {
 973       bool is_exec = parameters->options().output_is_executable();
 974       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
 975                                        Symbol_table::PREDEFINED,
 976                                        tls_segment, 0, 0,
 977                                        elfcpp::STT_TLS,
 978                                        elfcpp::STB_LOCAL,
 979                                        elfcpp::STV_HIDDEN, 0,
 980                                        (is_exec
 981                                         ? Symbol::SEGMENT_END
 982                                         : Symbol::SEGMENT_START),
 983                                        true);
 984     }
 985   this->tls_base_symbol_defined_ = true;
 986 }
 987
 988 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 989
 990 void
 991 Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
 992                                              Layout* layout)
 993 {
 994   if (this->plt_ == NULL)
 995     this->make_plt_section(symtab, layout);
 996
 997   if (!this->plt_->has_tlsdesc_entry())
 998     {
 999       // Allocate the TLSDESC_GOT entry.
1000       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1001       unsigned int got_offset = got->add_constant(0);
1002
1003       // Allocate the TLSDESC_PLT entry.
1004       this->plt_->reserve_tlsdesc_entry(got_offset);
1005     }
1006 }
1007
1008 // Create a GOT entry for the TLS module index.
1009
1010 unsigned int
1011 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1012                                    Sized_relobj<64, false>* object)
1013 {
1014   if (this->got_mod_index_offset_ == -1U)
1015     {
1016       gold_assert(symtab != NULL && layout != NULL && object != NULL);
1017       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1018       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1019       unsigned int got_offset = got->add_constant(0);
1020       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1021                           got_offset, 0);
1022       got->add_constant(0);
1023       this->got_mod_index_offset_ = got_offset;
1024     }
1025   return this->got_mod_index_offset_;
1026 }
1027
1028 // Optimize the TLS relocation type based on what we know about the
1029 // symbol.  IS_FINAL is true if the final address of this symbol is
1030 // known at link time.
1031
1032 tls::Tls_optimization
1033 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
1034 {
1035   // If we are generating a shared library, then we can't do anything
1036   // in the linker.
1037   if (parameters->options().shared())
1038     return tls::TLSOPT_NONE;
1039
1040   switch (r_type)
1041     {
1042     case elfcpp::R_X86_64_TLSGD:
1043     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1044     case elfcpp::R_X86_64_TLSDESC_CALL:
1045       // These are General-Dynamic which permits fully general TLS
1046       // access.  Since we know that we are generating an executable,
1047       // we can convert this to Initial-Exec.  If we also know that
1048       // this is a local symbol, we can further switch to Local-Exec.
1049       if (is_final)
1050         return tls::TLSOPT_TO_LE;
1051       return tls::TLSOPT_TO_IE;
1052
1053     case elfcpp::R_X86_64_TLSLD:
1054       // This is Local-Dynamic, which refers to a local symbol in the
1055       // dynamic TLS block.  Since we know that we generating an
1056       // executable, we can switch to Local-Exec.
1057       return tls::TLSOPT_TO_LE;
1058
1059     case elfcpp::R_X86_64_DTPOFF32:
1060     case elfcpp::R_X86_64_DTPOFF64:
1061       // Another Local-Dynamic reloc.
1062       return tls::TLSOPT_TO_LE;
1063
1064     case elfcpp::R_X86_64_GOTTPOFF:
1065       // These are Initial-Exec relocs which get the thread offset
1066       // from the GOT.  If we know that we are linking against the
1067       // local symbol, we can switch to Local-Exec, which links the
1068       // thread offset into the instruction.
1069       if (is_final)
1070         return tls::TLSOPT_TO_LE;
1071       return tls::TLSOPT_NONE;
1072
1073     case elfcpp::R_X86_64_TPOFF32:
1074       // When we already have Local-Exec, there is nothing further we
1075       // can do.
1076       return tls::TLSOPT_NONE;
1077
1078     default:
1079       gold_unreachable();
1080     }
1081 }
1082
1083 // Report an unsupported relocation against a local symbol.
1084
1085 void
1086 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
1087                                              unsigned int r_type)
1088 {
1089   gold_error(_("%s: unsupported reloc %u against local symbol"),
1090              object->name().c_str(), r_type);
1091 }
1092
1093 // We are about to emit a dynamic relocation of type R_TYPE.  If the
1094 // dynamic linker does not support it, issue an error.  The GNU linker
1095 // only issues a non-PIC error for an allocated read-only section.
1096 // Here we know the section is allocated, but we don't know that it is
1097 // read-only.  But we check for all the relocation types which the
1098 // glibc dynamic linker supports, so it seems appropriate to issue an
1099 // error even if the section is not read-only.
1100
1101 void
1102 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
1103 {
1104   switch (r_type)
1105     {
1106       // These are the relocation types supported by glibc for x86_64.
1107     case elfcpp::R_X86_64_RELATIVE:
1108     case elfcpp::R_X86_64_GLOB_DAT:
1109     case elfcpp::R_X86_64_JUMP_SLOT:
1110     case elfcpp::R_X86_64_DTPMOD64:
1111     case elfcpp::R_X86_64_DTPOFF64:
1112     case elfcpp::R_X86_64_TPOFF64:
1113     case elfcpp::R_X86_64_64:
1114     case elfcpp::R_X86_64_32:
1115     case elfcpp::R_X86_64_PC32:
1116     case elfcpp::R_X86_64_COPY:
1117       return;
1118
1119     default:
1120       // This prevents us from issuing more than one error per reloc
1121       // section.  But we can still wind up issuing more than one
1122       // error per object file.
1123       if (this->issued_non_pic_error_)
1124         return;
1125       gold_assert(parameters->options().output_is_position_independent());
1126       object->error(_("requires unsupported dynamic reloc; "
1127                       "recompile with -fPIC"));
1128       this->issued_non_pic_error_ = true;
1129       return;
1130
1131     case elfcpp::R_X86_64_NONE:
1132       gold_unreachable();
1133     }
1134 }
1135
1136 // Scan a relocation for a local symbol.
1137
1138 inline void
1139 Target_x86_64::Scan::local(Symbol_table* symtab,
1140                            Layout* layout,
1141                            Target_x86_64* target,
1142                            Sized_relobj<64, false>* object,
1143                            unsigned int data_shndx,
1144                            Output_section* output_section,
1145                            const elfcpp::Rela<64, false>& reloc,
1146                            unsigned int r_type,
1147                            const elfcpp::Sym<64, false>& lsym)
1148 {
1149   switch (r_type)
1150     {
1151     case elfcpp::R_X86_64_NONE:
1152     case elfcpp::R_386_GNU_VTINHERIT:
1153     case elfcpp::R_386_GNU_VTENTRY:
1154       break;
1155
1156     case elfcpp::R_X86_64_64:
1157       // If building a shared library (or a position-independent
1158       // executable), we need to create a dynamic relocation for this
1159       // location.  The relocation applied at link time will apply the
1160       // link-time value, so we flag the location with an
1161       // R_X86_64_RELATIVE relocation so the dynamic loader can
1162       // relocate it easily.
1163       if (parameters->options().output_is_position_independent())
1164         {
1165           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1166           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1167           rela_dyn->add_local_relative(object, r_sym,
1168                                        elfcpp::R_X86_64_RELATIVE,
1169                                        output_section, data_shndx,
1170                                        reloc.get_r_offset(),
1171                                        reloc.get_r_addend());
1172         }
1173       break;
1174
1175     case elfcpp::R_X86_64_32:
1176     case elfcpp::R_X86_64_32S:
1177     case elfcpp::R_X86_64_16:
1178     case elfcpp::R_X86_64_8:
1179       // If building a shared library (or a position-independent
1180       // executable), we need to create a dynamic relocation for this
1181       // location.  We can't use an R_X86_64_RELATIVE relocation
1182       // because that is always a 64-bit relocation.
1183       if (parameters->options().output_is_position_independent())
1184         {
1185           this->check_non_pic(object, r_type);
1186
1187           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1188           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1189           if (lsym.get_st_type() != elfcpp::STT_SECTION)
1190             rela_dyn->add_local(object, r_sym, r_type, output_section,
1191                                 data_shndx, reloc.get_r_offset(),
1192                                 reloc.get_r_addend());
1193           else
1194             {
1195               gold_assert(lsym.get_st_value() == 0);
1196               unsigned int shndx = lsym.get_st_shndx();
1197               bool is_ordinary;
1198               shndx = object->adjust_sym_shndx(r_sym, shndx,
1199                                                &is_ordinary);
1200               if (!is_ordinary)
1201                 object->error(_("section symbol %u has bad shndx %u"),
1202                               r_sym, shndx);
1203               else
1204                 rela_dyn->add_local_section(object, shndx,
1205                                             r_type, output_section,
1206                                             data_shndx, reloc.get_r_offset(),
1207                                             reloc.get_r_addend());
1208             }
1209         }
1210       break;
1211
1212     case elfcpp::R_X86_64_PC64:
1213     case elfcpp::R_X86_64_PC32:
1214     case elfcpp::R_X86_64_PC16:
1215     case elfcpp::R_X86_64_PC8:
1216       break;
1217
1218     case elfcpp::R_X86_64_PLT32:
1219       // Since we know this is a local symbol, we can handle this as a
1220       // PC32 reloc.
1221       break;
1222
1223     case elfcpp::R_X86_64_GOTPC32:
1224     case elfcpp::R_X86_64_GOTOFF64:
1225     case elfcpp::R_X86_64_GOTPC64:
1226     case elfcpp::R_X86_64_PLTOFF64:
1227       // We need a GOT section.
1228       target->got_section(symtab, layout);
1229       // For PLTOFF64, we'd normally want a PLT section, but since we
1230       // know this is a local symbol, no PLT is needed.
1231       break;
1232
1233     case elfcpp::R_X86_64_GOT64:
1234     case elfcpp::R_X86_64_GOT32:
1235     case elfcpp::R_X86_64_GOTPCREL64:
1236     case elfcpp::R_X86_64_GOTPCREL:
1237     case elfcpp::R_X86_64_GOTPLT64:
1238       {
1239         // The symbol requires a GOT entry.
1240         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1241         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1242         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1243           {
1244             // If we are generating a shared object, we need to add a
1245             // dynamic relocation for this symbol's GOT entry.
1246             if (parameters->options().output_is_position_independent())
1247               {
1248                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1249                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
1250                 if (r_type != elfcpp::R_X86_64_GOT32)
1251                   rela_dyn->add_local_relative(
1252                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
1253                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1254                 else
1255                   {
1256                     this->check_non_pic(object, r_type);
1257
1258                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1259                     rela_dyn->add_local(
1260                         object, r_sym, r_type, got,
1261                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
1262                   }
1263               }
1264           }
1265         // For GOTPLT64, we'd normally want a PLT section, but since
1266         // we know this is a local symbol, no PLT is needed.
1267       }
1268       break;
1269
1270     case elfcpp::R_X86_64_COPY:
1271     case elfcpp::R_X86_64_GLOB_DAT:
1272     case elfcpp::R_X86_64_JUMP_SLOT:
1273     case elfcpp::R_X86_64_RELATIVE:
1274       // These are outstanding tls relocs, which are unexpected when linking
1275     case elfcpp::R_X86_64_TPOFF64:
1276     case elfcpp::R_X86_64_DTPMOD64:
1277     case elfcpp::R_X86_64_TLSDESC:
1278       gold_error(_("%s: unexpected reloc %u in object file"),
1279                  object->name().c_str(), r_type);
1280       break;
1281
1282       // These are initial tls relocs, which are expected when linking
1283     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1284     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1285     case elfcpp::R_X86_64_TLSDESC_CALL:
1286     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1287     case elfcpp::R_X86_64_DTPOFF32:
1288     case elfcpp::R_X86_64_DTPOFF64:
1289     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1290     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1291       {
1292         bool output_is_shared = parameters->options().shared();
1293         const tls::Tls_optimization optimized_type
1294             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1295         switch (r_type)
1296           {
1297           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1298             if (optimized_type == tls::TLSOPT_NONE)
1299               {
1300                 // Create a pair of GOT entries for the module index and
1301                 // dtv-relative offset.
1302                 Output_data_got<64, false>* got
1303                     = target->got_section(symtab, layout);
1304                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1305                 unsigned int shndx = lsym.get_st_shndx();
1306                 bool is_ordinary;
1307                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1308                 if (!is_ordinary)
1309                   object->error(_("local symbol %u has bad shndx %u"),
1310                               r_sym, shndx);
1311                 else
1312                   got->add_local_pair_with_rela(object, r_sym,
1313                                                 shndx,
1314                                                 GOT_TYPE_TLS_PAIR,
1315                                                 target->rela_dyn_section(layout),
1316                                                 elfcpp::R_X86_64_DTPMOD64, 0);
1317               }
1318             else if (optimized_type != tls::TLSOPT_TO_LE)
1319               unsupported_reloc_local(object, r_type);
1320             break;
1321
1322           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1323             target->define_tls_base_symbol(symtab, layout);
1324             if (optimized_type == tls::TLSOPT_NONE)
1325               {
1326                 // Create reserved PLT and GOT entries for the resolver.
1327                 target->reserve_tlsdesc_entries(symtab, layout);
1328
1329                 // Generate a double GOT entry with an
1330                 // R_X86_64_TLSDESC reloc.  The R_X86_64_TLSDESC reloc
1331                 // is resolved lazily, so the GOT entry needs to be in
1332                 // an area in .got.plt, not .got.  Call got_section to
1333                 // make sure the section has been created.
1334                 target->got_section(symtab, layout);
1335                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1336                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1337                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1338                   {
1339                     unsigned int got_offset = got->add_constant(0);
1340                     got->add_constant(0);
1341                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1342                                                  got_offset);
1343                     Reloc_section* rt = target->rela_tlsdesc_section(layout);
1344                     // We store the arguments we need in a vector, and
1345                     // use the index into the vector as the parameter
1346                     // to pass to the target specific routines.
1347                     uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
1348                     void* arg = reinterpret_cast<void*>(intarg);
1349                     rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1350                                             got, got_offset, 0);
1351                   }
1352               }
1353             else if (optimized_type != tls::TLSOPT_TO_LE)
1354               unsupported_reloc_local(object, r_type);
1355             break;
1356
1357           case elfcpp::R_X86_64_TLSDESC_CALL:
1358             break;
1359
1360           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1361             if (optimized_type == tls::TLSOPT_NONE)
1362               {
1363                 // Create a GOT entry for the module index.
1364                 target->got_mod_index_entry(symtab, layout, object);
1365               }
1366             else if (optimized_type != tls::TLSOPT_TO_LE)
1367               unsupported_reloc_local(object, r_type);
1368             break;
1369
1370           case elfcpp::R_X86_64_DTPOFF32:
1371           case elfcpp::R_X86_64_DTPOFF64:
1372             break;
1373
1374           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1375             layout->set_has_static_tls();
1376             if (optimized_type == tls::TLSOPT_NONE)
1377               {
1378                 // Create a GOT entry for the tp-relative offset.
1379                 Output_data_got<64, false>* got
1380                     = target->got_section(symtab, layout);
1381                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1382                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1383                                          target->rela_dyn_section(layout),
1384                                          elfcpp::R_X86_64_TPOFF64);
1385               }
1386             else if (optimized_type != tls::TLSOPT_TO_LE)
1387               unsupported_reloc_local(object, r_type);
1388             break;
1389
1390           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1391             layout->set_has_static_tls();
1392             if (output_is_shared)
1393               unsupported_reloc_local(object, r_type);
1394             break;
1395
1396           default:
1397             gold_unreachable();
1398           }
1399       }
1400       break;
1401
1402     case elfcpp::R_X86_64_SIZE32:
1403     case elfcpp::R_X86_64_SIZE64:
1404     default:
1405       gold_error(_("%s: unsupported reloc %u against local symbol"),
1406                  object->name().c_str(), r_type);
1407       break;
1408     }
1409 }
1410
1411
1412 // Report an unsupported relocation against a global symbol.
1413
1414 void
1415 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1416                                               unsigned int r_type,
1417                                               Symbol* gsym)
1418 {
1419   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1420              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1421 }
1422
1423 // Returns true if this relocation type could be that of a function pointer.
1424 inline bool
1425 Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
1426 {
1427   switch (r_type)
1428     {
1429     case elfcpp::R_X86_64_64:
1430     case elfcpp::R_X86_64_32:
1431     case elfcpp::R_X86_64_32S:
1432     case elfcpp::R_X86_64_16:
1433     case elfcpp::R_X86_64_8:
1434     case elfcpp::R_X86_64_GOT64:
1435     case elfcpp::R_X86_64_GOT32:
1436     case elfcpp::R_X86_64_GOTPCREL64:
1437     case elfcpp::R_X86_64_GOTPCREL:
1438     case elfcpp::R_X86_64_GOTPLT64:
1439       {
1440         return true;
1441       }
1442     }
1443   return false;
1444 }
1445
1446 // For safe ICF, scan a relocation for a local symbol to check if it
1447 // corresponds to a function pointer being taken.  In that case mark
1448 // the function whose pointer was taken as not foldable.
1449
1450 inline bool
1451 Target_x86_64::Scan::local_reloc_may_be_function_pointer(
1452   Symbol_table* ,
1453   Layout* ,
1454   Target_x86_64* ,
1455   Sized_relobj<64, false>* ,
1456   unsigned int ,
1457   Output_section* ,
1458   const elfcpp::Rela<64, false>& ,
1459   unsigned int r_type,
1460   const elfcpp::Sym<64, false>&)
1461 {
1462   // When building a shared library, do not fold any local symbols as it is
1463   // not possible to distinguish pointer taken versus a call by looking at
1464   // the relocation types.
1465   return (parameters->options().shared()
1466           || possible_function_pointer_reloc(r_type));
1467 }
1468
1469 // For safe ICF, scan a relocation for a global symbol to check if it
1470 // corresponds to a function pointer being taken.  In that case mark
1471 // the function whose pointer was taken as not foldable.
1472
1473 inline bool
1474 Target_x86_64::Scan::global_reloc_may_be_function_pointer(
1475   Symbol_table*,
1476   Layout* ,
1477   Target_x86_64* ,
1478   Sized_relobj<64, false>* ,
1479   unsigned int ,
1480   Output_section* ,
1481   const elfcpp::Rela<64, false>& ,
1482   unsigned int r_type,
1483   Symbol* gsym)
1484 {
1485   // When building a shared library, do not fold symbols whose visibility
1486   // is hidden, internal or protected.
1487   return ((parameters->options().shared()
1488            && (gsym->visibility() == elfcpp::STV_INTERNAL
1489                || gsym->visibility() == elfcpp::STV_PROTECTED
1490                || gsym->visibility() == elfcpp::STV_HIDDEN))
1491           || possible_function_pointer_reloc(r_type));
1492 }
1493
1494 // Scan a relocation for a global symbol.
1495
1496 inline void
1497 Target_x86_64::Scan::global(Symbol_table* symtab,
1498                             Layout* layout,
1499                             Target_x86_64* target,
1500                             Sized_relobj<64, false>* object,
1501                             unsigned int data_shndx,
1502                             Output_section* output_section,
1503                             const elfcpp::Rela<64, false>& reloc,
1504                             unsigned int r_type,
1505                             Symbol* gsym)
1506 {
1507   switch (r_type)
1508     {
1509     case elfcpp::R_X86_64_NONE:
1510     case elfcpp::R_386_GNU_VTINHERIT:
1511     case elfcpp::R_386_GNU_VTENTRY:
1512       break;
1513
1514     case elfcpp::R_X86_64_64:
1515     case elfcpp::R_X86_64_32:
1516     case elfcpp::R_X86_64_32S:
1517     case elfcpp::R_X86_64_16:
1518     case elfcpp::R_X86_64_8:
1519       {
1520         // Make a PLT entry if necessary.
1521         if (gsym->needs_plt_entry())
1522           {
1523             target->make_plt_entry(symtab, layout, gsym);
1524             // Since this is not a PC-relative relocation, we may be
1525             // taking the address of a function. In that case we need to
1526             // set the entry in the dynamic symbol table to the address of
1527             // the PLT entry.
1528             if (gsym->is_from_dynobj() && !parameters->options().shared())
1529               gsym->set_needs_dynsym_value();
1530           }
1531         // Make a dynamic relocation if necessary.
1532         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1533           {
1534             if (gsym->may_need_copy_reloc())
1535               {
1536                 target->copy_reloc(symtab, layout, object,
1537                                    data_shndx, output_section, gsym, reloc);
1538               }
1539             else if (r_type == elfcpp::R_X86_64_64
1540                      && gsym->can_use_relative_reloc(false))
1541               {
1542                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1543                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1544                                               output_section, object,
1545                                               data_shndx, reloc.get_r_offset(),
1546                                               reloc.get_r_addend());
1547               }
1548             else
1549               {
1550                 this->check_non_pic(object, r_type);
1551                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1552                 rela_dyn->add_global(gsym, r_type, output_section, object,
1553                                      data_shndx, reloc.get_r_offset(),
1554                                      reloc.get_r_addend());
1555               }
1556           }
1557       }
1558       break;
1559
1560     case elfcpp::R_X86_64_PC64:
1561     case elfcpp::R_X86_64_PC32:
1562     case elfcpp::R_X86_64_PC16:
1563     case elfcpp::R_X86_64_PC8:
1564       {
1565         // Make a PLT entry if necessary.
1566         if (gsym->needs_plt_entry())
1567           target->make_plt_entry(symtab, layout, gsym);
1568         // Make a dynamic relocation if necessary.
1569         int flags = Symbol::NON_PIC_REF;
1570         if (gsym->is_func())
1571           flags |= Symbol::FUNCTION_CALL;
1572         if (gsym->needs_dynamic_reloc(flags))
1573           {
1574             if (gsym->may_need_copy_reloc())
1575               {
1576                 target->copy_reloc(symtab, layout, object,
1577                                    data_shndx, output_section, gsym, reloc);
1578               }
1579             else
1580               {
1581                 this->check_non_pic(object, r_type);
1582                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1583                 rela_dyn->add_global(gsym, r_type, output_section, object,
1584                                      data_shndx, reloc.get_r_offset(),
1585                                      reloc.get_r_addend());
1586               }
1587           }
1588       }
1589       break;
1590
1591     case elfcpp::R_X86_64_GOT64:
1592     case elfcpp::R_X86_64_GOT32:
1593     case elfcpp::R_X86_64_GOTPCREL64:
1594     case elfcpp::R_X86_64_GOTPCREL:
1595     case elfcpp::R_X86_64_GOTPLT64:
1596       {
1597         // The symbol requires a GOT entry.
1598         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1599         if (gsym->final_value_is_known())
1600           got->add_global(gsym, GOT_TYPE_STANDARD);
1601         else
1602           {
1603             // If this symbol is not fully resolved, we need to add a
1604             // dynamic relocation for it.
1605             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1606             if (gsym->is_from_dynobj()
1607                 || gsym->is_undefined()
1608                 || gsym->is_preemptible())
1609               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1610                                         elfcpp::R_X86_64_GLOB_DAT);
1611             else
1612               {
1613                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1614                   rela_dyn->add_global_relative(
1615                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1616                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1617               }
1618           }
1619         // For GOTPLT64, we also need a PLT entry (but only if the
1620         // symbol is not fully resolved).
1621         if (r_type == elfcpp::R_X86_64_GOTPLT64
1622             && !gsym->final_value_is_known())
1623           target->make_plt_entry(symtab, layout, gsym);
1624       }
1625       break;
1626
1627     case elfcpp::R_X86_64_PLT32:
1628       // If the symbol is fully resolved, this is just a PC32 reloc.
1629       // Otherwise we need a PLT entry.
1630       if (gsym->final_value_is_known())
1631         break;
1632       // If building a shared library, we can also skip the PLT entry
1633       // if the symbol is defined in the output file and is protected
1634       // or hidden.
1635       if (gsym->is_defined()
1636           && !gsym->is_from_dynobj()
1637           && !gsym->is_preemptible())
1638         break;
1639       target->make_plt_entry(symtab, layout, gsym);
1640       break;
1641
1642     case elfcpp::R_X86_64_GOTPC32:
1643     case elfcpp::R_X86_64_GOTOFF64:
1644     case elfcpp::R_X86_64_GOTPC64:
1645     case elfcpp::R_X86_64_PLTOFF64:
1646       // We need a GOT section.
1647       target->got_section(symtab, layout);
1648       // For PLTOFF64, we also need a PLT entry (but only if the
1649       // symbol is not fully resolved).
1650       if (r_type == elfcpp::R_X86_64_PLTOFF64
1651           && !gsym->final_value_is_known())
1652         target->make_plt_entry(symtab, layout, gsym);
1653       break;
1654
1655     case elfcpp::R_X86_64_COPY:
1656     case elfcpp::R_X86_64_GLOB_DAT:
1657     case elfcpp::R_X86_64_JUMP_SLOT:
1658     case elfcpp::R_X86_64_RELATIVE:
1659       // These are outstanding tls relocs, which are unexpected when linking
1660     case elfcpp::R_X86_64_TPOFF64:
1661     case elfcpp::R_X86_64_DTPMOD64:
1662     case elfcpp::R_X86_64_TLSDESC:
1663       gold_error(_("%s: unexpected reloc %u in object file"),
1664                  object->name().c_str(), r_type);
1665       break;
1666
1667       // These are initial tls relocs, which are expected for global()
1668     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1669     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1670     case elfcpp::R_X86_64_TLSDESC_CALL:
1671     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1672     case elfcpp::R_X86_64_DTPOFF32:
1673     case elfcpp::R_X86_64_DTPOFF64:
1674     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1675     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1676       {
1677         const bool is_final = gsym->final_value_is_known();
1678         const tls::Tls_optimization optimized_type
1679             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1680         switch (r_type)
1681           {
1682           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1683             if (optimized_type == tls::TLSOPT_NONE)
1684               {
1685                 // Create a pair of GOT entries for the module index and
1686                 // dtv-relative offset.
1687                 Output_data_got<64, false>* got
1688                     = target->got_section(symtab, layout);
1689                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1690                                                target->rela_dyn_section(layout),
1691                                                elfcpp::R_X86_64_DTPMOD64,
1692                                                elfcpp::R_X86_64_DTPOFF64);
1693               }
1694             else if (optimized_type == tls::TLSOPT_TO_IE)
1695               {
1696                 // Create a GOT entry for the tp-relative offset.
1697                 Output_data_got<64, false>* got
1698                     = target->got_section(symtab, layout);
1699                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1700                                           target->rela_dyn_section(layout),
1701                                           elfcpp::R_X86_64_TPOFF64);
1702               }
1703             else if (optimized_type != tls::TLSOPT_TO_LE)
1704               unsupported_reloc_global(object, r_type, gsym);
1705             break;
1706
1707           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1708             target->define_tls_base_symbol(symtab, layout);
1709             if (optimized_type == tls::TLSOPT_NONE)
1710               {
1711                 // Create reserved PLT and GOT entries for the resolver.
1712                 target->reserve_tlsdesc_entries(symtab, layout);
1713
1714                 // Create a double GOT entry with an R_X86_64_TLSDESC
1715                 // reloc.  The R_X86_64_TLSDESC reloc is resolved
1716                 // lazily, so the GOT entry needs to be in an area in
1717                 // .got.plt, not .got.  Call got_section to make sure
1718                 // the section has been created.
1719                 target->got_section(symtab, layout);
1720                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
1721                 Reloc_section *rt = target->rela_tlsdesc_section(layout);
1722                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
1723                                                elfcpp::R_X86_64_TLSDESC, 0);
1724               }
1725             else if (optimized_type == tls::TLSOPT_TO_IE)
1726               {
1727                 // Create a GOT entry for the tp-relative offset.
1728                 Output_data_got<64, false>* got
1729                     = target->got_section(symtab, layout);
1730                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1731                                           target->rela_dyn_section(layout),
1732                                           elfcpp::R_X86_64_TPOFF64);
1733               }
1734             else if (optimized_type != tls::TLSOPT_TO_LE)
1735               unsupported_reloc_global(object, r_type, gsym);
1736             break;
1737
1738           case elfcpp::R_X86_64_TLSDESC_CALL:
1739             break;
1740
1741           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1742             if (optimized_type == tls::TLSOPT_NONE)
1743               {
1744                 // Create a GOT entry for the module index.
1745                 target->got_mod_index_entry(symtab, layout, object);
1746               }
1747             else if (optimized_type != tls::TLSOPT_TO_LE)
1748               unsupported_reloc_global(object, r_type, gsym);
1749             break;
1750
1751           case elfcpp::R_X86_64_DTPOFF32:
1752           case elfcpp::R_X86_64_DTPOFF64:
1753             break;
1754
1755           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1756             layout->set_has_static_tls();
1757             if (optimized_type == tls::TLSOPT_NONE)
1758               {
1759                 // Create a GOT entry for the tp-relative offset.
1760                 Output_data_got<64, false>* got
1761                     = target->got_section(symtab, layout);
1762                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1763                                           target->rela_dyn_section(layout),
1764                                           elfcpp::R_X86_64_TPOFF64);
1765               }
1766             else if (optimized_type != tls::TLSOPT_TO_LE)
1767               unsupported_reloc_global(object, r_type, gsym);
1768             break;
1769
1770           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1771             layout->set_has_static_tls();
1772             if (parameters->options().shared())
1773               unsupported_reloc_local(object, r_type);
1774             break;
1775
1776           default:
1777             gold_unreachable();
1778           }
1779       }
1780       break;
1781
1782     case elfcpp::R_X86_64_SIZE32:
1783     case elfcpp::R_X86_64_SIZE64:
1784     default:
1785       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1786                  object->name().c_str(), r_type,
1787                  gsym->demangled_name().c_str());
1788       break;
1789     }
1790 }
1791
1792 void
1793 Target_x86_64::gc_process_relocs(Symbol_table* symtab,
1794                                  Layout* layout,
1795                                  Sized_relobj<64, false>* object,
1796                                  unsigned int data_shndx,
1797                                  unsigned int sh_type,
1798                                  const unsigned char* prelocs,
1799                                  size_t reloc_count,
1800                                  Output_section* output_section,
1801                                  bool needs_special_offset_handling,
1802                                  size_t local_symbol_count,
1803                                  const unsigned char* plocal_symbols)
1804 {
1805
1806   if (sh_type == elfcpp::SHT_REL)
1807     {
1808       return;
1809     }
1810
1811    gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1812                            Target_x86_64::Scan,
1813                            Target_x86_64::Relocatable_size_for_reloc>(
1814     symtab,
1815     layout,
1816     this,
1817     object,
1818     data_shndx,
1819     prelocs,
1820     reloc_count,
1821     output_section,
1822     needs_special_offset_handling,
1823     local_symbol_count,
1824     plocal_symbols);
1825
1826 }
1827 // Scan relocations for a section.
1828
1829 void
1830 Target_x86_64::scan_relocs(Symbol_table* symtab,
1831                            Layout* layout,
1832                            Sized_relobj<64, false>* object,
1833                            unsigned int data_shndx,
1834                            unsigned int sh_type,
1835                            const unsigned char* prelocs,
1836                            size_t reloc_count,
1837                            Output_section* output_section,
1838                            bool needs_special_offset_handling,
1839                            size_t local_symbol_count,
1840                            const unsigned char* plocal_symbols)
1841 {
1842   if (sh_type == elfcpp::SHT_REL)
1843     {
1844       gold_error(_("%s: unsupported REL reloc section"),
1845                  object->name().c_str());
1846       return;
1847     }
1848
1849   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1850       Target_x86_64::Scan>(
1851     symtab,
1852     layout,
1853     this,
1854     object,
1855     data_shndx,
1856     prelocs,
1857     reloc_count,
1858     output_section,
1859     needs_special_offset_handling,
1860     local_symbol_count,
1861     plocal_symbols);
1862 }
1863
1864 // Finalize the sections.
1865
1866 void
1867 Target_x86_64::do_finalize_sections(
1868     Layout* layout,
1869     const Input_objects*,
1870     Symbol_table* symtab)
1871 {
1872   const Reloc_section* rel_plt = (this->plt_ == NULL
1873                                   ? NULL
1874                                   : this->plt_->rela_plt());
1875   layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
1876                                   this->rela_dyn_, true, false);
1877
1878   // Fill in some more dynamic tags.
1879   Output_data_dynamic* const odyn = layout->dynamic_data();
1880   if (odyn != NULL)
1881     {
1882       if (this->plt_ != NULL
1883           && this->plt_->output_section() != NULL
1884           && this->plt_->has_tlsdesc_entry())
1885         {
1886           unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
1887           unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
1888           this->got_->finalize_data_size();
1889           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
1890                                         this->plt_, plt_offset);
1891           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
1892                                         this->got_, got_offset);
1893         }
1894     }
1895
1896   // Emit any relocs we saved in an attempt to avoid generating COPY
1897   // relocs.
1898   if (this->copy_relocs_.any_saved_relocs())
1899     this->copy_relocs_.emit(this->rela_dyn_section(layout));
1900
1901   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1902   // the .got.plt section.
1903   Symbol* sym = this->global_offset_table_;
1904   if (sym != NULL)
1905     {
1906       uint64_t data_size = this->got_plt_->current_data_size();
1907       symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
1908     }
1909 }
1910
1911 // Perform a relocation.
1912
1913 inline bool
1914 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1915                                   Target_x86_64* target,
1916                                   Output_section*,
1917                                   size_t relnum,
1918                                   const elfcpp::Rela<64, false>& rela,
1919                                   unsigned int r_type,
1920                                   const Sized_symbol<64>* gsym,
1921                                   const Symbol_value<64>* psymval,
1922                                   unsigned char* view,
1923                                   elfcpp::Elf_types<64>::Elf_Addr address,
1924                                   section_size_type view_size)
1925 {
1926   if (this->skip_call_tls_get_addr_)
1927     {
1928       if ((r_type != elfcpp::R_X86_64_PLT32
1929            && r_type != elfcpp::R_X86_64_PC32)
1930           || gsym == NULL
1931           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1932         {
1933           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1934                                  _("missing expected TLS relocation"));
1935         }
1936       else
1937         {
1938           this->skip_call_tls_get_addr_ = false;
1939           return false;
1940         }
1941     }
1942
1943   // Pick the value to use for symbols defined in shared objects.
1944   Symbol_value<64> symval;
1945   if (gsym != NULL
1946       && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
1947                               || r_type == elfcpp::R_X86_64_PC32
1948                               || r_type == elfcpp::R_X86_64_PC16
1949                               || r_type == elfcpp::R_X86_64_PC8))
1950     {
1951       symval.set_output_value(target->plt_section()->address()
1952                               + gsym->plt_offset());
1953       psymval = &symval;
1954     }
1955
1956   const Sized_relobj<64, false>* object = relinfo->object;
1957   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1958
1959   // Get the GOT offset if needed.
1960   // The GOT pointer points to the end of the GOT section.
1961   // We need to subtract the size of the GOT section to get
1962   // the actual offset to use in the relocation.
1963   bool have_got_offset = false;
1964   unsigned int got_offset = 0;
1965   switch (r_type)
1966     {
1967     case elfcpp::R_X86_64_GOT32:
1968     case elfcpp::R_X86_64_GOT64:
1969     case elfcpp::R_X86_64_GOTPLT64:
1970     case elfcpp::R_X86_64_GOTPCREL:
1971     case elfcpp::R_X86_64_GOTPCREL64:
1972       if (gsym != NULL)
1973         {
1974           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1975           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1976         }
1977       else
1978         {
1979           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1980           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1981           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1982                         - target->got_size());
1983         }
1984       have_got_offset = true;
1985       break;
1986
1987     default:
1988       break;
1989     }
1990
1991   switch (r_type)
1992     {
1993     case elfcpp::R_X86_64_NONE:
1994     case elfcpp::R_386_GNU_VTINHERIT:
1995     case elfcpp::R_386_GNU_VTENTRY:
1996       break;
1997
1998     case elfcpp::R_X86_64_64:
1999       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
2000       break;
2001
2002     case elfcpp::R_X86_64_PC64:
2003       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
2004                                               address);
2005       break;
2006
2007     case elfcpp::R_X86_64_32:
2008       // FIXME: we need to verify that value + addend fits into 32 bits:
2009       //    uint64_t x = value + addend;
2010       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
2011       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
2012       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2013       break;
2014
2015     case elfcpp::R_X86_64_32S:
2016       // FIXME: we need to verify that value + addend fits into 32 bits:
2017       //    int64_t x = value + addend;   // note this quantity is signed!
2018       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
2019       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
2020       break;
2021
2022     case elfcpp::R_X86_64_PC32:
2023       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2024                                               address);
2025       break;
2026
2027     case elfcpp::R_X86_64_16:
2028       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
2029       break;
2030
2031     case elfcpp::R_X86_64_PC16:
2032       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
2033                                               address);
2034       break;
2035
2036     case elfcpp::R_X86_64_8:
2037       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
2038       break;
2039
2040     case elfcpp::R_X86_64_PC8:
2041       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
2042                                              address);
2043       break;
2044
2045     case elfcpp::R_X86_64_PLT32:
2046       gold_assert(gsym == NULL
2047                   || gsym->has_plt_offset()
2048                   || gsym->final_value_is_known()
2049                   || (gsym->is_defined()
2050                       && !gsym->is_from_dynobj()
2051                       && !gsym->is_preemptible()));
2052       // Note: while this code looks the same as for R_X86_64_PC32, it
2053       // behaves differently because psymval was set to point to
2054       // the PLT entry, rather than the symbol, in Scan::global().
2055       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
2056                                               address);
2057       break;
2058
2059     case elfcpp::R_X86_64_PLTOFF64:
2060       {
2061         gold_assert(gsym);
2062         gold_assert(gsym->has_plt_offset()
2063                     || gsym->final_value_is_known());
2064         elfcpp::Elf_types<64>::Elf_Addr got_address;
2065         got_address = target->got_section(NULL, NULL)->address();
2066         Relocate_functions<64, false>::rela64(view, object, psymval,
2067                                               addend - got_address);
2068       }
2069
2070     case elfcpp::R_X86_64_GOT32:
2071       gold_assert(have_got_offset);
2072       Relocate_functions<64, false>::rela32(view, got_offset, addend);
2073       break;
2074
2075     case elfcpp::R_X86_64_GOTPC32:
2076       {
2077         gold_assert(gsym);
2078         elfcpp::Elf_types<64>::Elf_Addr value;
2079         value = target->got_plt_section()->address();
2080         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2081       }
2082       break;
2083
2084     case elfcpp::R_X86_64_GOT64:
2085       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
2086       // Since we always add a PLT entry, this is equivalent.
2087     case elfcpp::R_X86_64_GOTPLT64:
2088       gold_assert(have_got_offset);
2089       Relocate_functions<64, false>::rela64(view, got_offset, addend);
2090       break;
2091
2092     case elfcpp::R_X86_64_GOTPC64:
2093       {
2094         gold_assert(gsym);
2095         elfcpp::Elf_types<64>::Elf_Addr value;
2096         value = target->got_plt_section()->address();
2097         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2098       }
2099       break;
2100
2101     case elfcpp::R_X86_64_GOTOFF64:
2102       {
2103         elfcpp::Elf_types<64>::Elf_Addr value;
2104         value = (psymval->value(object, 0)
2105                  - target->got_plt_section()->address());
2106         Relocate_functions<64, false>::rela64(view, value, addend);
2107       }
2108       break;
2109
2110     case elfcpp::R_X86_64_GOTPCREL:
2111       {
2112         gold_assert(have_got_offset);
2113         elfcpp::Elf_types<64>::Elf_Addr value;
2114         value = target->got_plt_section()->address() + got_offset;
2115         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2116       }
2117       break;
2118
2119     case elfcpp::R_X86_64_GOTPCREL64:
2120       {
2121         gold_assert(have_got_offset);
2122         elfcpp::Elf_types<64>::Elf_Addr value;
2123         value = target->got_plt_section()->address() + got_offset;
2124         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
2125       }
2126       break;
2127
2128     case elfcpp::R_X86_64_COPY:
2129     case elfcpp::R_X86_64_GLOB_DAT:
2130     case elfcpp::R_X86_64_JUMP_SLOT:
2131     case elfcpp::R_X86_64_RELATIVE:
2132       // These are outstanding tls relocs, which are unexpected when linking
2133     case elfcpp::R_X86_64_TPOFF64:
2134     case elfcpp::R_X86_64_DTPMOD64:
2135     case elfcpp::R_X86_64_TLSDESC:
2136       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2137                              _("unexpected reloc %u in object file"),
2138                              r_type);
2139       break;
2140
2141       // These are initial tls relocs, which are expected when linking
2142     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2143     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2144     case elfcpp::R_X86_64_TLSDESC_CALL:
2145     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2146     case elfcpp::R_X86_64_DTPOFF32:
2147     case elfcpp::R_X86_64_DTPOFF64:
2148     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2149     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2150       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
2151                          view, address, view_size);
2152       break;
2153
2154     case elfcpp::R_X86_64_SIZE32:
2155     case elfcpp::R_X86_64_SIZE64:
2156     default:
2157       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2158                              _("unsupported reloc %u"),
2159                              r_type);
2160       break;
2161     }
2162
2163   return true;
2164 }
2165
2166 // Perform a TLS relocation.
2167
2168 inline void
2169 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
2170                                       Target_x86_64* target,
2171                                       size_t relnum,
2172                                       const elfcpp::Rela<64, false>& rela,
2173                                       unsigned int r_type,
2174                                       const Sized_symbol<64>* gsym,
2175                                       const Symbol_value<64>* psymval,
2176                                       unsigned char* view,
2177                                       elfcpp::Elf_types<64>::Elf_Addr address,
2178                                       section_size_type view_size)
2179 {
2180   Output_segment* tls_segment = relinfo->layout->tls_segment();
2181
2182   const Sized_relobj<64, false>* object = relinfo->object;
2183   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2184
2185   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
2186
2187   const bool is_final = (gsym == NULL
2188                          ? !parameters->options().shared()
2189                          : gsym->final_value_is_known());
2190   const tls::Tls_optimization optimized_type
2191       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
2192   switch (r_type)
2193     {
2194     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2195       this->saw_tls_block_reloc_ = true;
2196       if (optimized_type == tls::TLSOPT_TO_LE)
2197         {
2198           gold_assert(tls_segment != NULL);
2199           this->tls_gd_to_le(relinfo, relnum, tls_segment,
2200                              rela, r_type, value, view,
2201                              view_size);
2202           break;
2203         }
2204       else
2205         {
2206           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2207                                    ? GOT_TYPE_TLS_OFFSET
2208                                    : GOT_TYPE_TLS_PAIR);
2209           unsigned int got_offset;
2210           if (gsym != NULL)
2211             {
2212               gold_assert(gsym->has_got_offset(got_type));
2213               got_offset = gsym->got_offset(got_type) - target->got_size();
2214             }
2215           else
2216             {
2217               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2218               gold_assert(object->local_has_got_offset(r_sym, got_type));
2219               got_offset = (object->local_got_offset(r_sym, got_type)
2220                             - target->got_size());
2221             }
2222           if (optimized_type == tls::TLSOPT_TO_IE)
2223             {
2224               gold_assert(tls_segment != NULL);
2225               value = target->got_plt_section()->address() + got_offset;
2226               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
2227                                  value, view, address, view_size);
2228               break;
2229             }
2230           else if (optimized_type == tls::TLSOPT_NONE)
2231             {
2232               // Relocate the field with the offset of the pair of GOT
2233               // entries.
2234               value = target->got_plt_section()->address() + got_offset;
2235               Relocate_functions<64, false>::pcrela32(view, value, addend,
2236                                                       address);
2237               break;
2238             }
2239         }
2240       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2241                              _("unsupported reloc %u"), r_type);
2242       break;
2243
2244     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2245     case elfcpp::R_X86_64_TLSDESC_CALL:
2246       this->saw_tls_block_reloc_ = true;
2247       if (optimized_type == tls::TLSOPT_TO_LE)
2248         {
2249           gold_assert(tls_segment != NULL);
2250           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
2251                                   rela, r_type, value, view,
2252                                   view_size);
2253           break;
2254         }
2255       else
2256         {
2257           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
2258                                    ? GOT_TYPE_TLS_OFFSET
2259                                    : GOT_TYPE_TLS_DESC);
2260           unsigned int got_offset = 0;
2261           if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
2262               && optimized_type == tls::TLSOPT_NONE)
2263             {
2264               // We created GOT entries in the .got.tlsdesc portion of
2265               // the .got.plt section, but the offset stored in the
2266               // symbol is the offset within .got.tlsdesc.
2267               got_offset = (target->got_size()
2268                             + target->got_plt_section()->data_size());
2269             }
2270           if (gsym != NULL)
2271             {
2272               gold_assert(gsym->has_got_offset(got_type));
2273               got_offset += gsym->got_offset(got_type) - target->got_size();
2274             }
2275           else
2276             {
2277               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2278               gold_assert(object->local_has_got_offset(r_sym, got_type));
2279               got_offset += (object->local_got_offset(r_sym, got_type)
2280                              - target->got_size());
2281             }
2282           if (optimized_type == tls::TLSOPT_TO_IE)
2283             {
2284               gold_assert(tls_segment != NULL);
2285               value = target->got_plt_section()->address() + got_offset;
2286               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
2287                                       rela, r_type, value, view, address,
2288                                       view_size);
2289               break;
2290             }
2291           else if (optimized_type == tls::TLSOPT_NONE)
2292             {
2293               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2294                 {
2295                   // Relocate the field with the offset of the pair of GOT
2296                   // entries.
2297                   value = target->got_plt_section()->address() + got_offset;
2298                   Relocate_functions<64, false>::pcrela32(view, value, addend,
2299                                                           address);
2300                 }
2301               break;
2302             }
2303         }
2304       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2305                              _("unsupported reloc %u"), r_type);
2306       break;
2307
2308     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2309       this->saw_tls_block_reloc_ = true;
2310       if (optimized_type == tls::TLSOPT_TO_LE)
2311         {
2312           gold_assert(tls_segment != NULL);
2313           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
2314                              value, view, view_size);
2315           break;
2316         }
2317       else if (optimized_type == tls::TLSOPT_NONE)
2318         {
2319           // Relocate the field with the offset of the GOT entry for
2320           // the module index.
2321           unsigned int got_offset;
2322           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2323                         - target->got_size());
2324           value = target->got_plt_section()->address() + got_offset;
2325           Relocate_functions<64, false>::pcrela32(view, value, addend,
2326                                                   address);
2327           break;
2328         }
2329       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2330                              _("unsupported reloc %u"), r_type);
2331       break;
2332
2333     case elfcpp::R_X86_64_DTPOFF32:
2334       if (optimized_type == tls::TLSOPT_TO_LE)
2335         {
2336           // This relocation type is used in debugging information.
2337           // In that case we need to not optimize the value.  If we
2338           // haven't seen a TLSLD reloc, then we assume we should not
2339           // optimize this reloc.
2340           if (this->saw_tls_block_reloc_)
2341             {
2342               gold_assert(tls_segment != NULL);
2343               value -= tls_segment->memsz();
2344             }
2345         }
2346       Relocate_functions<64, false>::rela32(view, value, addend);
2347       break;
2348
2349     case elfcpp::R_X86_64_DTPOFF64:
2350       if (optimized_type == tls::TLSOPT_TO_LE)
2351         {
2352           // See R_X86_64_DTPOFF32, just above, for why we test this.
2353           if (this->saw_tls_block_reloc_)
2354             {
2355               gold_assert(tls_segment != NULL);
2356               value -= tls_segment->memsz();
2357             }
2358         }
2359       Relocate_functions<64, false>::rela64(view, value, addend);
2360       break;
2361
2362     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2363       if (optimized_type == tls::TLSOPT_TO_LE)
2364         {
2365           gold_assert(tls_segment != NULL);
2366           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2367                                                 rela, r_type, value, view,
2368                                                 view_size);
2369           break;
2370         }
2371       else if (optimized_type == tls::TLSOPT_NONE)
2372         {
2373           // Relocate the field with the offset of the GOT entry for
2374           // the tp-relative offset of the symbol.
2375           unsigned int got_offset;
2376           if (gsym != NULL)
2377             {
2378               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
2379               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
2380                             - target->got_size());
2381             }
2382           else
2383             {
2384               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
2385               gold_assert(object->local_has_got_offset(r_sym,
2386                                                        GOT_TYPE_TLS_OFFSET));
2387               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
2388                             - target->got_size());
2389             }
2390           value = target->got_plt_section()->address() + got_offset;
2391           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2392           break;
2393         }
2394       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2395                              _("unsupported reloc type %u"),
2396                              r_type);
2397       break;
2398
2399     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2400       value -= tls_segment->memsz();
2401       Relocate_functions<64, false>::rela32(view, value, addend);
2402       break;
2403     }
2404 }
2405
2406 // Do a relocation in which we convert a TLS General-Dynamic to an
2407 // Initial-Exec.
2408
2409 inline void
2410 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
2411                                       size_t relnum,
2412                                       Output_segment*,
2413                                       const elfcpp::Rela<64, false>& rela,
2414                                       unsigned int,
2415                                       elfcpp::Elf_types<64>::Elf_Addr value,
2416                                       unsigned char* view,
2417                                       elfcpp::Elf_types<64>::Elf_Addr address,
2418                                       section_size_type view_size)
2419 {
2420   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2421   // .word 0x6666; rex64; call __tls_get_addr
2422   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
2423
2424   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2425   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2426
2427   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2428                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2429   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2430                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2431
2432   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
2433
2434   const elfcpp::Elf_Xword addend = rela.get_r_addend();
2435   Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
2436
2437   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2438   // We can skip it.
2439   this->skip_call_tls_get_addr_ = true;
2440 }
2441
2442 // Do a relocation in which we convert a TLS General-Dynamic to a
2443 // Local-Exec.
2444
2445 inline void
2446 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
2447                                       size_t relnum,
2448                                       Output_segment* tls_segment,
2449                                       const elfcpp::Rela<64, false>& rela,
2450                                       unsigned int,
2451                                       elfcpp::Elf_types<64>::Elf_Addr value,
2452                                       unsigned char* view,
2453                                       section_size_type view_size)
2454 {
2455   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
2456   // .word 0x6666; rex64; call __tls_get_addr
2457   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
2458
2459   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
2460   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
2461
2462   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2463                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
2464   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2465                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
2466
2467   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
2468
2469   value -= tls_segment->memsz();
2470   Relocate_functions<64, false>::rela32(view + 8, value, 0);
2471
2472   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2473   // We can skip it.
2474   this->skip_call_tls_get_addr_ = true;
2475 }
2476
2477 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
2478
2479 inline void
2480 Target_x86_64::Relocate::tls_desc_gd_to_ie(
2481     const Relocate_info<64, false>* relinfo,
2482     size_t relnum,
2483     Output_segment*,
2484     const elfcpp::Rela<64, false>& rela,
2485     unsigned int r_type,
2486     elfcpp::Elf_types<64>::Elf_Addr value,
2487     unsigned char* view,
2488     elfcpp::Elf_types<64>::Elf_Addr address,
2489     section_size_type view_size)
2490 {
2491   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2492     {
2493       // leaq foo@tlsdesc(%rip), %rax
2494       // ==> movq foo@gottpoff(%rip), %rax
2495       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2496       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2497       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2498                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2499       view[-2] = 0x8b;
2500       const elfcpp::Elf_Xword addend = rela.get_r_addend();
2501       Relocate_functions<64, false>::pcrela32(view, value, addend, address);
2502     }
2503   else
2504     {
2505       // call *foo@tlscall(%rax)
2506       // ==> nop; nop
2507       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2508       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2509       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2510                      view[0] == 0xff && view[1] == 0x10);
2511       view[0] = 0x66;
2512       view[1] = 0x90;
2513     }
2514 }
2515
2516 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
2517
2518 inline void
2519 Target_x86_64::Relocate::tls_desc_gd_to_le(
2520     const Relocate_info<64, false>* relinfo,
2521     size_t relnum,
2522     Output_segment* tls_segment,
2523     const elfcpp::Rela<64, false>& rela,
2524     unsigned int r_type,
2525     elfcpp::Elf_types<64>::Elf_Addr value,
2526     unsigned char* view,
2527     section_size_type view_size)
2528 {
2529   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
2530     {
2531       // leaq foo@tlsdesc(%rip), %rax
2532       // ==> movq foo@tpoff, %rax
2533       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2534       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2535       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2536                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
2537       view[-2] = 0xc7;
2538       view[-1] = 0xc0;
2539       value -= tls_segment->memsz();
2540       Relocate_functions<64, false>::rela32(view, value, 0);
2541     }
2542   else
2543     {
2544       // call *foo@tlscall(%rax)
2545       // ==> nop; nop
2546       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
2547       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
2548       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2549                      view[0] == 0xff && view[1] == 0x10);
2550       view[0] = 0x66;
2551       view[1] = 0x90;
2552     }
2553 }
2554
2555 inline void
2556 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
2557                                       size_t relnum,
2558                                       Output_segment*,
2559                                       const elfcpp::Rela<64, false>& rela,
2560                                       unsigned int,
2561                                       elfcpp::Elf_types<64>::Elf_Addr,
2562                                       unsigned char* view,
2563                                       section_size_type view_size)
2564 {
2565   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
2566   // ... leq foo@dtpoff(%rax),%reg
2567   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
2568
2569   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2570   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
2571
2572   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
2573                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
2574
2575   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
2576
2577   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
2578
2579   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2580   // We can skip it.
2581   this->skip_call_tls_get_addr_ = true;
2582 }
2583
2584 // Do a relocation in which we convert a TLS Initial-Exec to a
2585 // Local-Exec.
2586
2587 inline void
2588 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
2589                                       size_t relnum,
2590                                       Output_segment* tls_segment,
2591                                       const elfcpp::Rela<64, false>& rela,
2592                                       unsigned int,
2593                                       elfcpp::Elf_types<64>::Elf_Addr value,
2594                                       unsigned char* view,
2595                                       section_size_type view_size)
2596 {
2597   // We need to examine the opcodes to figure out which instruction we
2598   // are looking at.
2599
2600   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
2601   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
2602
2603   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
2604   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
2605
2606   unsigned char op1 = view[-3];
2607   unsigned char op2 = view[-2];
2608   unsigned char op3 = view[-1];
2609   unsigned char reg = op3 >> 3;
2610
2611   if (op2 == 0x8b)
2612     {
2613       // movq
2614       if (op1 == 0x4c)
2615         view[-3] = 0x49;
2616       view[-2] = 0xc7;
2617       view[-1] = 0xc0 | reg;
2618     }
2619   else if (reg == 4)
2620     {
2621       // Special handling for %rsp.
2622       if (op1 == 0x4c)
2623         view[-3] = 0x49;
2624       view[-2] = 0x81;
2625       view[-1] = 0xc0 | reg;
2626     }
2627   else
2628     {
2629       // addq
2630       if (op1 == 0x4c)
2631         view[-3] = 0x4d;
2632       view[-2] = 0x8d;
2633       view[-1] = 0x80 | reg | (reg << 3);
2634     }
2635
2636   value -= tls_segment->memsz();
2637   Relocate_functions<64, false>::rela32(view, value, 0);
2638 }
2639
2640 // Relocate section data.
2641
2642 void
2643 Target_x86_64::relocate_section(
2644     const Relocate_info<64, false>* relinfo,
2645     unsigned int sh_type,
2646     const unsigned char* prelocs,
2647     size_t reloc_count,
2648     Output_section* output_section,
2649     bool needs_special_offset_handling,
2650     unsigned char* view,
2651     elfcpp::Elf_types<64>::Elf_Addr address,
2652     section_size_type view_size,
2653     const Reloc_symbol_changes* reloc_symbol_changes)
2654 {
2655   gold_assert(sh_type == elfcpp::SHT_RELA);
2656
2657   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2658                          Target_x86_64::Relocate>(
2659     relinfo,
2660     this,
2661     prelocs,
2662     reloc_count,
2663     output_section,
2664     needs_special_offset_handling,
2665     view,
2666     address,
2667     view_size,
2668     reloc_symbol_changes);
2669 }
2670
2671 // Return the size of a relocation while scanning during a relocatable
2672 // link.
2673
2674 unsigned int
2675 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2676     unsigned int r_type,
2677     Relobj* object)
2678 {
2679   switch (r_type)
2680     {
2681     case elfcpp::R_X86_64_NONE:
2682     case elfcpp::R_386_GNU_VTINHERIT:
2683     case elfcpp::R_386_GNU_VTENTRY:
2684     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2685     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2686     case elfcpp::R_X86_64_TLSDESC_CALL:
2687     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2688     case elfcpp::R_X86_64_DTPOFF32:
2689     case elfcpp::R_X86_64_DTPOFF64:
2690     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2691     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2692       return 0;
2693
2694     case elfcpp::R_X86_64_64:
2695     case elfcpp::R_X86_64_PC64:
2696     case elfcpp::R_X86_64_GOTOFF64:
2697     case elfcpp::R_X86_64_GOTPC64:
2698     case elfcpp::R_X86_64_PLTOFF64:
2699     case elfcpp::R_X86_64_GOT64:
2700     case elfcpp::R_X86_64_GOTPCREL64:
2701     case elfcpp::R_X86_64_GOTPCREL:
2702     case elfcpp::R_X86_64_GOTPLT64:
2703       return 8;
2704
2705     case elfcpp::R_X86_64_32:
2706     case elfcpp::R_X86_64_32S:
2707     case elfcpp::R_X86_64_PC32:
2708     case elfcpp::R_X86_64_PLT32:
2709     case elfcpp::R_X86_64_GOTPC32:
2710     case elfcpp::R_X86_64_GOT32:
2711       return 4;
2712
2713     case elfcpp::R_X86_64_16:
2714     case elfcpp::R_X86_64_PC16:
2715       return 2;
2716
2717     case elfcpp::R_X86_64_8:
2718     case elfcpp::R_X86_64_PC8:
2719       return 1;
2720
2721     case elfcpp::R_X86_64_COPY:
2722     case elfcpp::R_X86_64_GLOB_DAT:
2723     case elfcpp::R_X86_64_JUMP_SLOT:
2724     case elfcpp::R_X86_64_RELATIVE:
2725       // These are outstanding tls relocs, which are unexpected when linking
2726     case elfcpp::R_X86_64_TPOFF64:
2727     case elfcpp::R_X86_64_DTPMOD64:
2728     case elfcpp::R_X86_64_TLSDESC:
2729       object->error(_("unexpected reloc %u in object file"), r_type);
2730       return 0;
2731
2732     case elfcpp::R_X86_64_SIZE32:
2733     case elfcpp::R_X86_64_SIZE64:
2734     default:
2735       object->error(_("unsupported reloc %u against local symbol"), r_type);
2736       return 0;
2737     }
2738 }
2739
2740 // Scan the relocs during a relocatable link.
2741
2742 void
2743 Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
2744                                        Layout* layout,
2745                                        Sized_relobj<64, false>* object,
2746                                        unsigned int data_shndx,
2747                                        unsigned int sh_type,
2748                                        const unsigned char* prelocs,
2749                                        size_t reloc_count,
2750                                        Output_section* output_section,
2751                                        bool needs_special_offset_handling,
2752                                        size_t local_symbol_count,
2753                                        const unsigned char* plocal_symbols,
2754                                        Relocatable_relocs* rr)
2755 {
2756   gold_assert(sh_type == elfcpp::SHT_RELA);
2757
2758   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2759     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2760
2761   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2762       Scan_relocatable_relocs>(
2763     symtab,
2764     layout,
2765     object,
2766     data_shndx,
2767     prelocs,
2768     reloc_count,
2769     output_section,
2770     needs_special_offset_handling,
2771     local_symbol_count,
2772     plocal_symbols,
2773     rr);
2774 }
2775
2776 // Relocate a section during a relocatable link.
2777
2778 void
2779 Target_x86_64::relocate_for_relocatable(
2780     const Relocate_info<64, false>* relinfo,
2781     unsigned int sh_type,
2782     const unsigned char* prelocs,
2783     size_t reloc_count,
2784     Output_section* output_section,
2785     off_t offset_in_output_section,
2786     const Relocatable_relocs* rr,
2787     unsigned char* view,
2788     elfcpp::Elf_types<64>::Elf_Addr view_address,
2789     section_size_type view_size,
2790     unsigned char* reloc_view,
2791     section_size_type reloc_view_size)
2792 {
2793   gold_assert(sh_type == elfcpp::SHT_RELA);
2794
2795   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2796     relinfo,
2797     prelocs,
2798     reloc_count,
2799     output_section,
2800     offset_in_output_section,
2801     rr,
2802     view,
2803     view_address,
2804     view_size,
2805     reloc_view,
2806     reloc_view_size);
2807 }
2808
2809 // Return the value to use for a dynamic which requires special
2810 // treatment.  This is how we support equality comparisons of function
2811 // pointers across shared library boundaries, as described in the
2812 // processor specific ABI supplement.
2813
2814 uint64_t
2815 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2816 {
2817   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2818   return this->plt_section()->address() + gsym->plt_offset();
2819 }
2820
2821 // Return a string used to fill a code section with nops to take up
2822 // the specified length.
2823
2824 std::string
2825 Target_x86_64::do_code_fill(section_size_type length) const
2826 {
2827   if (length >= 16)
2828     {
2829       // Build a jmpq instruction to skip over the bytes.
2830       unsigned char jmp[5];
2831       jmp[0] = 0xe9;
2832       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2833       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2834               + std::string(length - 5, '\0'));
2835     }
2836
2837   // Nop sequences of various lengths.
2838   const char nop1[1] = { 0x90 };                   // nop
2839   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2840   const char nop3[3] = { 0x0f, 0x1f, 0x00 };       // nop (%rax)
2841   const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00};  // nop 0(%rax)
2842   const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00,   // nop 0(%rax,%rax,1)
2843                          0x00 };
2844   const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44,   // nopw 0(%rax,%rax,1)
2845                          0x00, 0x00 };
2846   const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00,   // nopl 0L(%rax)
2847                          0x00, 0x00, 0x00 };
2848   const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00,   // nopl 0L(%rax,%rax,1)
2849                          0x00, 0x00, 0x00, 0x00 };
2850   const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84,   // nopw 0L(%rax,%rax,1)
2851                          0x00, 0x00, 0x00, 0x00,
2852                          0x00 };
2853   const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
2854                            0x84, 0x00, 0x00, 0x00,
2855                            0x00, 0x00 };
2856   const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
2857                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2858                            0x00, 0x00, 0x00 };
2859   const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
2860                            0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
2861                            0x00, 0x00, 0x00, 0x00 };
2862   const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2863                            0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
2864                            0x00, 0x00, 0x00, 0x00,
2865                            0x00 };
2866   const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2867                            0x66, 0x2e, 0x0f, 0x1f, // data16
2868                            0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2869                            0x00, 0x00 };
2870   const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
2871                            0x66, 0x66, 0x2e, 0x0f, // data16; data16
2872                            0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
2873                            0x00, 0x00, 0x00 };
2874
2875   const char* nops[16] = {
2876     NULL,
2877     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2878     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2879   };
2880
2881   return std::string(nops[length], length);
2882 }
2883
2884 // Return the addend to use for a target specific relocation.  The
2885 // only target specific relocation is R_X86_64_TLSDESC for a local
2886 // symbol.  We want to set the addend is the offset of the local
2887 // symbol in the TLS segment.
2888
2889 uint64_t
2890 Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
2891                                uint64_t) const
2892 {
2893   gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
2894   uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
2895   gold_assert(intarg < this->tlsdesc_reloc_info_.size());
2896   const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
2897   const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
2898   gold_assert(psymval->is_tls_symbol());
2899   // The value of a TLS symbol is the offset in the TLS segment.
2900   return psymval->value(ti.object, 0);
2901 }
2902
2903 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2904 // compiled with -fstack-split.  The function calls non-stack-split
2905 // code.  We have to change the function so that it always ensures
2906 // that it has enough stack space to run some random function.
2907
2908 void
2909 Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
2910                                   section_offset_type fnoffset,
2911                                   section_size_type fnsize,
2912                                   unsigned char* view,
2913                                   section_size_type view_size,
2914                                   std::string* from,
2915                                   std::string* to) const
2916 {
2917   // The function starts with a comparison of the stack pointer and a
2918   // field in the TCB.  This is followed by a jump.
2919
2920   // cmp %fs:NN,%rsp
2921   if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
2922       && fnsize > 9)
2923     {
2924       // We will call __morestack if the carry flag is set after this
2925       // comparison.  We turn the comparison into an stc instruction
2926       // and some nops.
2927       view[fnoffset] = '\xf9';
2928       this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
2929     }
2930   // lea NN(%rsp),%r10
2931   // lea NN(%rsp),%r11
2932   else if ((this->match_view(view, view_size, fnoffset,
2933                              "\x4c\x8d\x94\x24", 4)
2934             || this->match_view(view, view_size, fnoffset,
2935                                 "\x4c\x8d\x9c\x24", 4))
2936            && fnsize > 8)
2937     {
2938       // This is loading an offset from the stack pointer for a
2939       // comparison.  The offset is negative, so we decrease the
2940       // offset by the amount of space we need for the stack.  This
2941       // means we will avoid calling __morestack if there happens to
2942       // be plenty of space on the stack already.
2943       unsigned char* pval = view + fnoffset + 4;
2944       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2945       val -= parameters->options().split_stack_adjust_size();
2946       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2947     }
2948   else
2949     {
2950       if (!object->has_no_split_stack())
2951         object->error(_("failed to match split-stack sequence at "
2952                         "section %u offset %0zx"),
2953                       shndx, static_cast<size_t>(fnoffset));
2954       return;
2955     }
2956
2957   // We have to change the function so that it calls
2958   // __morestack_non_split instead of __morestack.  The former will
2959   // allocate additional stack space.
2960   *from = "__morestack";
2961   *to = "__morestack_non_split";
2962 }
2963
2964 // The selector for x86_64 object files.
2965
2966 class Target_selector_x86_64 : public Target_selector_freebsd
2967 {
2968 public:
2969   Target_selector_x86_64()
2970     : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
2971                               "elf64-x86-64-freebsd")
2972   { }
2973
2974   Target*
2975   do_instantiate_target()
2976   { return new Target_x86_64(); }
2977
2978 };
2979
2980 Target_selector_x86_64 target_selector_x86_64;
2981
2982 } // End anonymous namespace.