gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
   4 // Free Software Foundation, Inc.
   5 // Written by Ian Lance Taylor <iant@google.com>.
   6
   7 // This file is part of gold.
   8
   9 // This program is free software; you can redistribute it and/or modify
  10 // it under the terms of the GNU General Public License as published by
  11 // the Free Software Foundation; either version 3 of the License, or
  12 // (at your option) any later version.
  13
  14 // This program is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18
  19 // You should have received a copy of the GNU General Public License
  20 // along with this program; if not, write to the Free Software
  21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  22 // MA 02110-1301, USA.
  23
  24 #include "gold.h"
  25
  26 #include <cstring>
  27
  28 #include "elfcpp.h"
  29 #include "dwarf.h"
  30 #include "parameters.h"
  31 #include "reloc.h"
  32 #include "x86_64.h"
  33 #include "object.h"
  34 #include "symtab.h"
  35 #include "layout.h"
  36 #include "output.h"
  37 #include "copy-relocs.h"
  38 #include "target.h"
  39 #include "target-reloc.h"
  40 #include "target-select.h"
  41 #include "tls.h"
  42 #include "freebsd.h"
  43 #include "gc.h"
  44 #include "icf.h"
  45
  46 namespace
  47 {
  48
  49 using namespace gold;
  50
  51 // A class to handle the PLT data.
  52
  53 template<int size>
  54 class Output_data_plt_x86_64 : public Output_section_data
  55 {
  56  public:
  57   typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
  58
  59   Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
  60                          Output_data_space* got_plt,
  61                          Output_data_space* got_irelative)
  62     : Output_section_data(16), layout_(layout), tlsdesc_rel_(NULL),
  63       irelative_rel_(NULL), got_(got), got_plt_(got_plt),
  64       got_irelative_(got_irelative), count_(0), irelative_count_(0),
  65       tlsdesc_got_offset_(-1U), free_list_()
  66   { this->init(layout); }
  67
  68   Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
  69                          Output_data_space* got_plt,
  70                          Output_data_space* got_irelative,
  71                          unsigned int plt_count)
  72     : Output_section_data((plt_count + 1) * plt_entry_size, 16, false),
  73       layout_(layout), tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
  74       got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
  75       irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
  76   {
  77     this->init(layout);
  78
  79     // Initialize the free list and reserve the first entry.
  80     this->free_list_.init((plt_count + 1) * plt_entry_size, false);
  81     this->free_list_.remove(0, plt_entry_size);
  82   }
  83
  84   // Initialize the PLT section.
  85   void
  86   init(Layout* layout);
  87
  88   // Add an entry to the PLT.
  89   void
  90   add_entry(Symbol_table*, Layout*, Symbol* gsym);
  91
  92   // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
  93   unsigned int
  94   add_local_ifunc_entry(Symbol_table* symtab, Layout*,
  95                         Sized_relobj_file<size, false>* relobj,
  96                         unsigned int local_sym_index);
  97
  98   // Add the relocation for a PLT entry.
  99   void
 100   add_relocation(Symbol_table*, Layout*, Symbol* gsym,
 101                  unsigned int got_offset);
 102
 103   // Add the reserved TLSDESC_PLT entry to the PLT.
 104   void
 105   reserve_tlsdesc_entry(unsigned int got_offset)
 106   { this->tlsdesc_got_offset_ = got_offset; }
 107
 108   // Return true if a TLSDESC_PLT entry has been reserved.
 109   bool
 110   has_tlsdesc_entry() const
 111   { return this->tlsdesc_got_offset_ != -1U; }
 112
 113   // Return the GOT offset for the reserved TLSDESC_PLT entry.
 114   unsigned int
 115   get_tlsdesc_got_offset() const
 116   { return this->tlsdesc_got_offset_; }
 117
 118   // Return the offset of the reserved TLSDESC_PLT entry.
 119   unsigned int
 120   get_tlsdesc_plt_offset() const
 121   { return (this->count_ + this->irelative_count_ + 1) * plt_entry_size; }
 122
 123   // Return the .rela.plt section data.
 124   Reloc_section*
 125   rela_plt()
 126   { return this->rel_; }
 127
 128   // Return where the TLSDESC relocations should go.
 129   Reloc_section*
 130   rela_tlsdesc(Layout*);
 131
 132   // Return where the IRELATIVE relocations should go in the PLT
 133   // relocations.
 134   Reloc_section*
 135   rela_irelative(Symbol_table*, Layout*);
 136
 137   // Return whether we created a section for IRELATIVE relocations.
 138   bool
 139   has_irelative_section() const
 140   { return this->irelative_rel_ != NULL; }
 141
 142   // Return the number of PLT entries.
 143   unsigned int
 144   entry_count() const
 145   { return this->count_ + this->irelative_count_; }
 146
 147   // Return the offset of the first non-reserved PLT entry.
 148   static unsigned int
 149   first_plt_entry_offset()
 150   { return plt_entry_size; }
 151
 152   // Return the size of a PLT entry.
 153   static unsigned int
 154   get_plt_entry_size()
 155   { return plt_entry_size; }
 156
 157   // Reserve a slot in the PLT for an existing symbol in an incremental update.
 158   void
 159   reserve_slot(unsigned int plt_index)
 160   {
 161     this->free_list_.remove((plt_index + 1) * plt_entry_size,
 162                             (plt_index + 2) * plt_entry_size);
 163   }
 164
 165   // Return the PLT address to use for a global symbol.
 166   uint64_t
 167   address_for_global(const Symbol*);
 168
 169   // Return the PLT address to use for a local symbol.
 170   uint64_t
 171   address_for_local(const Relobj*, unsigned int symndx);
 172
 173  protected:
 174   void
 175   do_adjust_output_section(Output_section* os);
 176
 177   // Write to a map file.
 178   void
 179   do_print_to_mapfile(Mapfile* mapfile) const
 180   { mapfile->print_output_data(this, _("** PLT")); }
 181
 182  private:
 183   // The size of an entry in the PLT.
 184   static const int plt_entry_size = 16;
 185
 186   // The first entry in the PLT.
 187   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 188   // procedure linkage table for both programs and shared objects."
 189   static const unsigned char first_plt_entry[plt_entry_size];
 190
 191   // Other entries in the PLT for an executable.
 192   static const unsigned char plt_entry[plt_entry_size];
 193
 194   // The reserved TLSDESC entry in the PLT for an executable.
 195   static const unsigned char tlsdesc_plt_entry[plt_entry_size];
 196
 197   // The .eh_frame unwind information for the PLT.
 198   static const int plt_eh_frame_cie_size = 16;
 199   static const int plt_eh_frame_fde_size = 32;
 200   static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
 201   static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
 202
 203   // Set the final size.
 204   void
 205   set_final_data_size();
 206
 207   // Write out the PLT data.
 208   void
 209   do_write(Output_file*);
 210
 211   // A pointer to the Layout class, so that we can find the .dynamic
 212   // section when we write out the GOT PLT section.
 213   Layout* layout_;
 214   // The reloc section.
 215   Reloc_section* rel_;
 216   // The TLSDESC relocs, if necessary.  These must follow the regular
 217   // PLT relocs.
 218   Reloc_section* tlsdesc_rel_;
 219   // The IRELATIVE relocs, if necessary.  These must follow the
 220   // regular PLT relocations and the TLSDESC relocations.
 221   Reloc_section* irelative_rel_;
 222   // The .got section.
 223   Output_data_got<64, false>* got_;
 224   // The .got.plt section.
 225   Output_data_space* got_plt_;
 226   // The part of the .got.plt section used for IRELATIVE relocs.
 227   Output_data_space* got_irelative_;
 228   // The number of PLT entries.
 229   unsigned int count_;
 230   // Number of PLT entries with R_X86_64_IRELATIVE relocs.  These
 231   // follow the regular PLT entries.
 232   unsigned int irelative_count_;
 233   // Offset of the reserved TLSDESC_GOT entry when needed.
 234   unsigned int tlsdesc_got_offset_;
 235   // List of available regions within the section, for incremental
 236   // update links.
 237   Free_list free_list_;
 238 };
 239
 240 // The x86_64 target class.
 241 // See the ABI at
 242 //   http://www.x86-64.org/documentation/abi.pdf
 243 // TLS info comes from
 244 //   http://people.redhat.com/drepper/tls.pdf
 245 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
 246
 247 template<int size>
 248 class Target_x86_64 : public Sized_target<size, false>
 249 {
 250  public:
 251   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
 252   // uses only Elf64_Rela relocation entries with explicit addends."
 253   typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section;
 254
 255   Target_x86_64()
 256     : Sized_target<size, false>(&x86_64_info),
 257       got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
 258       got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL),
 259       rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY),
 260       dynbss_(NULL), got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
 261       tls_base_symbol_defined_(false)
 262   { }
 263
 264   // Hook for a new output section.
 265   void
 266   do_new_output_section(Output_section*) const;
 267
 268   // Scan the relocations to look for symbol adjustments.
 269   void
 270   gc_process_relocs(Symbol_table* symtab,
 271                     Layout* layout,
 272                     Sized_relobj_file<size, false>* object,
 273                     unsigned int data_shndx,
 274                     unsigned int sh_type,
 275                     const unsigned char* prelocs,
 276                     size_t reloc_count,
 277                     Output_section* output_section,
 278                     bool needs_special_offset_handling,
 279                     size_t local_symbol_count,
 280                     const unsigned char* plocal_symbols);
 281
 282   // Scan the relocations to look for symbol adjustments.
 283   void
 284   scan_relocs(Symbol_table* symtab,
 285               Layout* layout,
 286               Sized_relobj_file<size, false>* object,
 287               unsigned int data_shndx,
 288               unsigned int sh_type,
 289               const unsigned char* prelocs,
 290               size_t reloc_count,
 291               Output_section* output_section,
 292               bool needs_special_offset_handling,
 293               size_t local_symbol_count,
 294               const unsigned char* plocal_symbols);
 295
 296   // Finalize the sections.
 297   void
 298   do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
 299
 300   // Return the value to use for a dynamic which requires special
 301   // treatment.
 302   uint64_t
 303   do_dynsym_value(const Symbol*) const;
 304
 305   // Relocate a section.
 306   void
 307   relocate_section(const Relocate_info<size, false>*,
 308                    unsigned int sh_type,
 309                    const unsigned char* prelocs,
 310                    size_t reloc_count,
 311                    Output_section* output_section,
 312                    bool needs_special_offset_handling,
 313                    unsigned char* view,
 314                    typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 315                    section_size_type view_size,
 316                    const Reloc_symbol_changes*);
 317
 318   // Scan the relocs during a relocatable link.
 319   void
 320   scan_relocatable_relocs(Symbol_table* symtab,
 321                           Layout* layout,
 322                           Sized_relobj_file<size, false>* object,
 323                           unsigned int data_shndx,
 324                           unsigned int sh_type,
 325                           const unsigned char* prelocs,
 326                           size_t reloc_count,
 327                           Output_section* output_section,
 328                           bool needs_special_offset_handling,
 329                           size_t local_symbol_count,
 330                           const unsigned char* plocal_symbols,
 331                           Relocatable_relocs*);
 332
 333   // Relocate a section during a relocatable link.
 334   void
 335   relocate_for_relocatable(
 336       const Relocate_info<size, false>*,
 337       unsigned int sh_type,
 338       const unsigned char* prelocs,
 339       size_t reloc_count,
 340       Output_section* output_section,
 341       off_t offset_in_output_section,
 342       const Relocatable_relocs*,
 343       unsigned char* view,
 344       typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 345       section_size_type view_size,
 346       unsigned char* reloc_view,
 347       section_size_type reloc_view_size);
 348
 349   // Return a string used to fill a code section with nops.
 350   std::string
 351   do_code_fill(section_size_type length) const;
 352
 353   // Return whether SYM is defined by the ABI.
 354   bool
 355   do_is_defined_by_abi(const Symbol* sym) const
 356   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 357
 358   // Return the symbol index to use for a target specific relocation.
 359   // The only target specific relocation is R_X86_64_TLSDESC for a
 360   // local symbol, which is an absolute reloc.
 361   unsigned int
 362   do_reloc_symbol_index(void*, unsigned int r_type) const
 363   {
 364     gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
 365     return 0;
 366   }
 367
 368   // Return the addend to use for a target specific relocation.
 369   uint64_t
 370   do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
 371
 372   // Return the PLT section.
 373   uint64_t
 374   do_plt_address_for_global(const Symbol* gsym) const
 375   { return this->plt_section()->address_for_global(gsym); }
 376
 377   uint64_t
 378   do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
 379   { return this->plt_section()->address_for_local(relobj, symndx); }
 380
 381   // This function should be defined in targets that can use relocation
 382   // types to determine (implemented in local_reloc_may_be_function_pointer
 383   // and global_reloc_may_be_function_pointer)
 384   // if a function's pointer is taken.  ICF uses this in safe mode to only
 385   // fold those functions whose pointer is defintely not taken.  For x86_64
 386   // pie binaries, safe ICF cannot be done by looking at relocation types.
 387   bool
 388   do_can_check_for_function_pointers() const
 389   { return !parameters->options().pie(); }
 390
 391   // Return the base for a DW_EH_PE_datarel encoding.
 392   uint64_t
 393   do_ehframe_datarel_base() const;
 394
 395   // Adjust -fsplit-stack code which calls non-split-stack code.
 396   void
 397   do_calls_non_split(Relobj* object, unsigned int shndx,
 398                      section_offset_type fnoffset, section_size_type fnsize,
 399                      unsigned char* view, section_size_type view_size,
 400                      std::string* from, std::string* to) const;
 401
 402   // Return the size of the GOT section.
 403   section_size_type
 404   got_size() const
 405   {
 406     gold_assert(this->got_ != NULL);
 407     return this->got_->data_size();
 408   }
 409
 410   // Return the number of entries in the GOT.
 411   unsigned int
 412   got_entry_count() const
 413   {
 414     if (this->got_ == NULL)
 415       return 0;
 416     return this->got_size() / 8;
 417   }
 418
 419   // Return the number of entries in the PLT.
 420   unsigned int
 421   plt_entry_count() const;
 422
 423   // Return the offset of the first non-reserved PLT entry.
 424   unsigned int
 425   first_plt_entry_offset() const;
 426
 427   // Return the size of each PLT entry.
 428   unsigned int
 429   plt_entry_size() const;
 430
 431   // Create the GOT section for an incremental update.
 432   Output_data_got_base*
 433   init_got_plt_for_update(Symbol_table* symtab,
 434                           Layout* layout,
 435                           unsigned int got_count,
 436                           unsigned int plt_count);
 437
 438   // Reserve a GOT entry for a local symbol, and regenerate any
 439   // necessary dynamic relocations.
 440   void
 441   reserve_local_got_entry(unsigned int got_index,
 442                           Sized_relobj<size, false>* obj,
 443                           unsigned int r_sym,
 444                           unsigned int got_type);
 445
 446   // Reserve a GOT entry for a global symbol, and regenerate any
 447   // necessary dynamic relocations.
 448   void
 449   reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
 450                            unsigned int got_type);
 451
 452   // Register an existing PLT entry for a global symbol.
 453   void
 454   register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index,
 455                             Symbol* gsym);
 456
 457   // Force a COPY relocation for a given symbol.
 458   void
 459   emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t);
 460
 461   // Apply an incremental relocation.
 462   void
 463   apply_relocation(const Relocate_info<size, false>* relinfo,
 464                    typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
 465                    unsigned int r_type,
 466                    typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
 467                    const Symbol* gsym,
 468                    unsigned char* view,
 469                    typename elfcpp::Elf_types<size>::Elf_Addr address,
 470                    section_size_type view_size);
 471
 472   // Add a new reloc argument, returning the index in the vector.
 473   size_t
 474   add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym)
 475   {
 476     this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
 477     return this->tlsdesc_reloc_info_.size() - 1;
 478   }
 479
 480  private:
 481   // The class which scans relocations.
 482   class Scan
 483   {
 484   public:
 485     Scan()
 486       : issued_non_pic_error_(false)
 487     { }
 488
 489     static inline int
 490     get_reference_flags(unsigned int r_type);
 491
 492     inline void
 493     local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 494           Sized_relobj_file<size, false>* object,
 495           unsigned int data_shndx,
 496           Output_section* output_section,
 497           const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
 498           const elfcpp::Sym<size, false>& lsym);
 499
 500     inline void
 501     global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
 502            Sized_relobj_file<size, false>* object,
 503            unsigned int data_shndx,
 504            Output_section* output_section,
 505            const elfcpp::Rela<size, false>& reloc, unsigned int r_type,
 506            Symbol* gsym);
 507
 508     inline bool
 509     local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 510                                         Target_x86_64* target,
 511                                         Sized_relobj_file<size, false>* object,
 512                                         unsigned int data_shndx,
 513                                         Output_section* output_section,
 514                                         const elfcpp::Rela<size, false>& reloc,
 515                                         unsigned int r_type,
 516                                         const elfcpp::Sym<size, false>& lsym);
 517
 518     inline bool
 519     global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
 520                                          Target_x86_64* target,
 521                                          Sized_relobj_file<size, false>* object,
 522                                          unsigned int data_shndx,
 523                                          Output_section* output_section,
 524                                          const elfcpp::Rela<size, false>& reloc,
 525                                          unsigned int r_type,
 526                                          Symbol* gsym);
 527
 528   private:
 529     static void
 530     unsupported_reloc_local(Sized_relobj_file<size, false>*,
 531                             unsigned int r_type);
 532
 533     static void
 534     unsupported_reloc_global(Sized_relobj_file<size, false>*,
 535                              unsigned int r_type, Symbol*);
 536
 537     void
 538     check_non_pic(Relobj*, unsigned int r_type, Symbol*);
 539
 540     inline bool
 541     possible_function_pointer_reloc(unsigned int r_type);
 542
 543     bool
 544     reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*,
 545                               unsigned int r_type);
 546
 547     // Whether we have issued an error about a non-PIC compilation.
 548     bool issued_non_pic_error_;
 549   };
 550
 551   // The class which implements relocation.
 552   class Relocate
 553   {
 554    public:
 555     Relocate()
 556       : skip_call_tls_get_addr_(false)
 557     { }
 558
 559     ~Relocate()
 560     {
 561       if (this->skip_call_tls_get_addr_)
 562         {
 563           // FIXME: This needs to specify the location somehow.
 564           gold_error(_("missing expected TLS relocation"));
 565         }
 566     }
 567
 568     // Do a relocation.  Return false if the caller should not issue
 569     // any warnings about this relocation.
 570     inline bool
 571     relocate(const Relocate_info<size, false>*, Target_x86_64*,
 572              Output_section*,
 573              size_t relnum, const elfcpp::Rela<size, false>&,
 574              unsigned int r_type, const Sized_symbol<size>*,
 575              const Symbol_value<size>*,
 576              unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
 577              section_size_type);
 578
 579    private:
 580     // Do a TLS relocation.
 581     inline void
 582     relocate_tls(const Relocate_info<size, false>*, Target_x86_64*,
 583                  size_t relnum, const elfcpp::Rela<size, false>&,
 584                  unsigned int r_type, const Sized_symbol<size>*,
 585                  const Symbol_value<size>*,
 586                  unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr,
 587                  section_size_type);
 588
 589     // Do a TLS General-Dynamic to Initial-Exec transition.
 590     inline void
 591     tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
 592                  Output_segment* tls_segment,
 593                  const elfcpp::Rela<size, false>&, unsigned int r_type,
 594                  typename elfcpp::Elf_types<size>::Elf_Addr value,
 595                  unsigned char* view,
 596                  typename elfcpp::Elf_types<size>::Elf_Addr,
 597                  section_size_type view_size);
 598
 599     // Do a TLS General-Dynamic to Local-Exec transition.
 600     inline void
 601     tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
 602                  Output_segment* tls_segment,
 603                  const elfcpp::Rela<size, false>&, unsigned int r_type,
 604                  typename elfcpp::Elf_types<size>::Elf_Addr value,
 605                  unsigned char* view,
 606                  section_size_type view_size);
 607
 608     // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
 609     inline void
 610     tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum,
 611                       Output_segment* tls_segment,
 612                       const elfcpp::Rela<size, false>&, unsigned int r_type,
 613                       typename elfcpp::Elf_types<size>::Elf_Addr value,
 614                       unsigned char* view,
 615                       typename elfcpp::Elf_types<size>::Elf_Addr,
 616                       section_size_type view_size);
 617
 618     // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
 619     inline void
 620     tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum,
 621                       Output_segment* tls_segment,
 622                       const elfcpp::Rela<size, false>&, unsigned int r_type,
 623                       typename elfcpp::Elf_types<size>::Elf_Addr value,
 624                       unsigned char* view,
 625                       section_size_type view_size);
 626
 627     // Do a TLS Local-Dynamic to Local-Exec transition.
 628     inline void
 629     tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum,
 630                  Output_segment* tls_segment,
 631                  const elfcpp::Rela<size, false>&, unsigned int r_type,
 632                  typename elfcpp::Elf_types<size>::Elf_Addr value,
 633                  unsigned char* view,
 634                  section_size_type view_size);
 635
 636     // Do a TLS Initial-Exec to Local-Exec transition.
 637     static inline void
 638     tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum,
 639                  Output_segment* tls_segment,
 640                  const elfcpp::Rela<size, false>&, unsigned int r_type,
 641                  typename elfcpp::Elf_types<size>::Elf_Addr value,
 642                  unsigned char* view,
 643                  section_size_type view_size);
 644
 645     // This is set if we should skip the next reloc, which should be a
 646     // PLT32 reloc against ___tls_get_addr.
 647     bool skip_call_tls_get_addr_;
 648   };
 649
 650   // A class which returns the size required for a relocation type,
 651   // used while scanning relocs during a relocatable link.
 652   class Relocatable_size_for_reloc
 653   {
 654    public:
 655     unsigned int
 656     get_size_for_reloc(unsigned int, Relobj*);
 657   };
 658
 659   // Adjust TLS relocation type based on the options and whether this
 660   // is a local symbol.
 661   static tls::Tls_optimization
 662   optimize_tls_reloc(bool is_final, int r_type);
 663
 664   // Get the GOT section, creating it if necessary.
 665   Output_data_got<64, false>*
 666   got_section(Symbol_table*, Layout*);
 667
 668   // Get the GOT PLT section.
 669   Output_data_space*
 670   got_plt_section() const
 671   {
 672     gold_assert(this->got_plt_ != NULL);
 673     return this->got_plt_;
 674   }
 675
 676   // Get the GOT section for TLSDESC entries.
 677   Output_data_got<64, false>*
 678   got_tlsdesc_section() const
 679   {
 680     gold_assert(this->got_tlsdesc_ != NULL);
 681     return this->got_tlsdesc_;
 682   }
 683
 684   // Create the PLT section.
 685   void
 686   make_plt_section(Symbol_table* symtab, Layout* layout);
 687
 688   // Create a PLT entry for a global symbol.
 689   void
 690   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 691
 692   // Create a PLT entry for a local STT_GNU_IFUNC symbol.
 693   void
 694   make_local_ifunc_plt_entry(Symbol_table*, Layout*,
 695                              Sized_relobj_file<size, false>* relobj,
 696                              unsigned int local_sym_index);
 697
 698   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 699   void
 700   define_tls_base_symbol(Symbol_table*, Layout*);
 701
 702   // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
 703   void
 704   reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
 705
 706   // Create a GOT entry for the TLS module index.
 707   unsigned int
 708   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 709                       Sized_relobj_file<size, false>* object);
 710
 711   // Get the PLT section.
 712   Output_data_plt_x86_64<size>*
 713   plt_section() const
 714   {
 715     gold_assert(this->plt_ != NULL);
 716     return this->plt_;
 717   }
 718
 719   // Get the dynamic reloc section, creating it if necessary.
 720   Reloc_section*
 721   rela_dyn_section(Layout*);
 722
 723   // Get the section to use for TLSDESC relocations.
 724   Reloc_section*
 725   rela_tlsdesc_section(Layout*) const;
 726
 727   // Get the section to use for IRELATIVE relocations.
 728   Reloc_section*
 729   rela_irelative_section(Layout*);
 730
 731   // Add a potential copy relocation.
 732   void
 733   copy_reloc(Symbol_table* symtab, Layout* layout,
 734              Sized_relobj_file<size, false>* object,
 735              unsigned int shndx, Output_section* output_section,
 736              Symbol* sym, const elfcpp::Rela<size, false>& reloc)
 737   {
 738     this->copy_relocs_.copy_reloc(symtab, layout,
 739                                   symtab->get_sized_symbol<size>(sym),
 740                                   object, shndx, output_section,
 741                                   reloc, this->rela_dyn_section(layout));
 742   }
 743
 744   // Information about this specific target which we pass to the
 745   // general Target structure.
 746   static const Target::Target_info x86_64_info;
 747
 748   // The types of GOT entries needed for this platform.
 749   // These values are exposed to the ABI in an incremental link.
 750   // Do not renumber existing values without changing the version
 751   // number of the .gnu_incremental_inputs section.
 752   enum Got_type
 753   {
 754     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 755     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 756     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 757     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 758   };
 759
 760   // This type is used as the argument to the target specific
 761   // relocation routines.  The only target specific reloc is
 762   // R_X86_64_TLSDESC against a local symbol.
 763   struct Tlsdesc_info
 764   {
 765     Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym)
 766       : object(a_object), r_sym(a_r_sym)
 767     { }
 768
 769     // The object in which the local symbol is defined.
 770     Sized_relobj_file<size, false>* object;
 771     // The local symbol index in the object.
 772     unsigned int r_sym;
 773   };
 774
 775   // The GOT section.
 776   Output_data_got<64, false>* got_;
 777   // The PLT section.
 778   Output_data_plt_x86_64<size>* plt_;
 779   // The GOT PLT section.
 780   Output_data_space* got_plt_;
 781   // The GOT section for IRELATIVE relocations.
 782   Output_data_space* got_irelative_;
 783   // The GOT section for TLSDESC relocations.
 784   Output_data_got<64, false>* got_tlsdesc_;
 785   // The _GLOBAL_OFFSET_TABLE_ symbol.
 786   Symbol* global_offset_table_;
 787   // The dynamic reloc section.
 788   Reloc_section* rela_dyn_;
 789   // The section to use for IRELATIVE relocs.
 790   Reloc_section* rela_irelative_;
 791   // Relocs saved to avoid a COPY reloc.
 792   Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_;
 793   // Space for variables copied with a COPY reloc.
 794   Output_data_space* dynbss_;
 795   // Offset of the GOT entry for the TLS module index.
 796   unsigned int got_mod_index_offset_;
 797   // We handle R_X86_64_TLSDESC against a local symbol as a target
 798   // specific relocation.  Here we store the object and local symbol
 799   // index for the relocation.
 800   std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
 801   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 802   bool tls_base_symbol_defined_;
 803 };
 804
 805 template<>
 806 const Target::Target_info Target_x86_64<64>::x86_64_info =
 807 {
 808   64,                   // size
 809   false,                // is_big_endian
 810   elfcpp::EM_X86_64,    // machine_code
 811   false,                // has_make_symbol
 812   false,                // has_resolve
 813   true,                 // has_code_fill
 814   true,                 // is_default_stack_executable
 815   true,                 // can_icf_inline_merge_sections
 816   '\0',                 // wrap_char
 817   "/lib/ld64.so.1",     // program interpreter
 818   0x400000,             // default_text_segment_address
 819   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 820   0x1000,               // common_pagesize (overridable by -z common-page-size)
 821   elfcpp::SHN_UNDEF,    // small_common_shndx
 822   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 823   0,                    // small_common_section_flags
 824   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 825   NULL,                 // attributes_section
 826   NULL                  // attributes_vendor
 827 };
 828
 829 template<>
 830 const Target::Target_info Target_x86_64<32>::x86_64_info =
 831 {
 832   32,                   // size
 833   false,                // is_big_endian
 834   elfcpp::EM_X86_64,    // machine_code
 835   false,                // has_make_symbol
 836   false,                // has_resolve
 837   true,                 // has_code_fill
 838   true,                 // is_default_stack_executable
 839   true,                 // can_icf_inline_merge_sections
 840   '\0',                 // wrap_char
 841   "/libx32/ldx32.so.1", // program interpreter
 842   0x400000,             // default_text_segment_address
 843   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 844   0x1000,               // common_pagesize (overridable by -z common-page-size)
 845   elfcpp::SHN_UNDEF,    // small_common_shndx
 846   elfcpp::SHN_X86_64_LCOMMON,   // large_common_shndx
 847   0,                    // small_common_section_flags
 848   elfcpp::SHF_X86_64_LARGE,     // large_common_section_flags
 849   NULL,                 // attributes_section
 850   NULL                  // attributes_vendor
 851 };
 852
 853 // This is called when a new output section is created.  This is where
 854 // we handle the SHF_X86_64_LARGE.
 855
 856 template<int size>
 857 void
 858 Target_x86_64<size>::do_new_output_section(Output_section* os) const
 859 {
 860   if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
 861     os->set_is_large_section();
 862 }
 863
 864 // Get the GOT section, creating it if necessary.
 865
 866 template<int size>
 867 Output_data_got<64, false>*
 868 Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout)
 869 {
 870   if (this->got_ == NULL)
 871     {
 872       gold_assert(symtab != NULL && layout != NULL);
 873
 874       // When using -z now, we can treat .got.plt as a relro section.
 875       // Without -z now, it is modified after program startup by lazy
 876       // PLT relocations.
 877       bool is_got_plt_relro = parameters->options().now();
 878       Output_section_order got_order = (is_got_plt_relro
 879                                         ? ORDER_RELRO
 880                                         : ORDER_RELRO_LAST);
 881       Output_section_order got_plt_order = (is_got_plt_relro
 882                                             ? ORDER_RELRO
 883                                             : ORDER_NON_RELRO_FIRST);
 884
 885       this->got_ = new Output_data_got<64, false>();
 886
 887       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 888                                       (elfcpp::SHF_ALLOC
 889                                        | elfcpp::SHF_WRITE),
 890                                       this->got_, got_order, true);
 891
 892       this->got_plt_ = new Output_data_space(8, "** GOT PLT");
 893       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 894                                       (elfcpp::SHF_ALLOC
 895                                        | elfcpp::SHF_WRITE),
 896                                       this->got_plt_, got_plt_order,
 897                                       is_got_plt_relro);
 898
 899       // The first three entries are reserved.
 900       this->got_plt_->set_current_data_size(3 * 8);
 901
 902       if (!is_got_plt_relro)
 903         {
 904           // Those bytes can go into the relro segment.
 905           layout->increase_relro(3 * 8);
 906         }
 907
 908       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 909       this->global_offset_table_ =
 910         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 911                                       Symbol_table::PREDEFINED,
 912                                       this->got_plt_,
 913                                       0, 0, elfcpp::STT_OBJECT,
 914                                       elfcpp::STB_LOCAL,
 915                                       elfcpp::STV_HIDDEN, 0,
 916                                       false, false);
 917
 918       // If there are any IRELATIVE relocations, they get GOT entries
 919       // in .got.plt after the jump slot entries.
 920       this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT");
 921       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 922                                       (elfcpp::SHF_ALLOC
 923                                        | elfcpp::SHF_WRITE),
 924                                       this->got_irelative_,
 925                                       got_plt_order, is_got_plt_relro);
 926
 927       // If there are any TLSDESC relocations, they get GOT entries in
 928       // .got.plt after the jump slot and IRELATIVE entries.
 929       this->got_tlsdesc_ = new Output_data_got<64, false>();
 930       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 931                                       (elfcpp::SHF_ALLOC
 932                                        | elfcpp::SHF_WRITE),
 933                                       this->got_tlsdesc_,
 934                                       got_plt_order, is_got_plt_relro);
 935     }
 936
 937   return this->got_;
 938 }
 939
 940 // Get the dynamic reloc section, creating it if necessary.
 941
 942 template<int size>
 943 typename Target_x86_64<size>::Reloc_section*
 944 Target_x86_64<size>::rela_dyn_section(Layout* layout)
 945 {
 946   if (this->rela_dyn_ == NULL)
 947     {
 948       gold_assert(layout != NULL);
 949       this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
 950       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 951                                       elfcpp::SHF_ALLOC, this->rela_dyn_,
 952                                       ORDER_DYNAMIC_RELOCS, false);
 953     }
 954   return this->rela_dyn_;
 955 }
 956
 957 // Get the section to use for IRELATIVE relocs, creating it if
 958 // necessary.  These go in .rela.dyn, but only after all other dynamic
 959 // relocations.  They need to follow the other dynamic relocations so
 960 // that they can refer to global variables initialized by those
 961 // relocs.
 962
 963 template<int size>
 964 typename Target_x86_64<size>::Reloc_section*
 965 Target_x86_64<size>::rela_irelative_section(Layout* layout)
 966 {
 967   if (this->rela_irelative_ == NULL)
 968     {
 969       // Make sure we have already created the dynamic reloc section.
 970       this->rela_dyn_section(layout);
 971       this->rela_irelative_ = new Reloc_section(false);
 972       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 973                                       elfcpp::SHF_ALLOC, this->rela_irelative_,
 974                                       ORDER_DYNAMIC_RELOCS, false);
 975       gold_assert(this->rela_dyn_->output_section()
 976                   == this->rela_irelative_->output_section());
 977     }
 978   return this->rela_irelative_;
 979 }
 980
 981 // Initialize the PLT section.
 982
 983 template<int size>
 984 void
 985 Output_data_plt_x86_64<size>::init(Layout* layout)
 986 {
 987   this->rel_ = new Reloc_section(false);
 988   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 989                                   elfcpp::SHF_ALLOC, this->rel_,
 990                                   ORDER_DYNAMIC_PLT_RELOCS, false);
 991
 992   // Add unwind information if requested.
 993   if (parameters->options().ld_generated_unwind_info())
 994     layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
 995                                  plt_eh_frame_fde, plt_eh_frame_fde_size);
 996 }
 997
 998 template<int size>
 999 void
1000 Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os)
1001 {
1002   os->set_entsize(plt_entry_size);
1003 }
1004
1005 // Add an entry to the PLT.
1006
1007 template<int size>
1008 void
1009 Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout,
1010                                         Symbol* gsym)
1011 {
1012   gold_assert(!gsym->has_plt_offset());
1013
1014   unsigned int plt_index;
1015   off_t plt_offset;
1016   section_offset_type got_offset;
1017
1018   unsigned int* pcount;
1019   unsigned int offset;
1020   unsigned int reserved;
1021   Output_data_space* got;
1022   if (gsym->type() == elfcpp::STT_GNU_IFUNC
1023       && gsym->can_use_relative_reloc(false))
1024     {
1025       pcount = &this->irelative_count_;
1026       offset = 0;
1027       reserved = 0;
1028       got = this->got_irelative_;
1029     }
1030   else
1031     {
1032       pcount = &this->count_;
1033       offset = 1;
1034       reserved = 3;
1035       got = this->got_plt_;
1036     }
1037
1038   if (!this->is_data_size_valid())
1039     {
1040       // Note that when setting the PLT offset for a non-IRELATIVE
1041       // entry we skip the initial reserved PLT entry.
1042       plt_index = *pcount + offset;
1043       plt_offset = plt_index * plt_entry_size;
1044
1045       ++*pcount;
1046
1047       got_offset = (plt_index - offset + reserved) * 8;
1048       gold_assert(got_offset == got->current_data_size());
1049
1050       // Every PLT entry needs a GOT entry which points back to the PLT
1051       // entry (this will be changed by the dynamic linker, normally
1052       // lazily when the function is called).
1053       got->set_current_data_size(got_offset + 8);
1054     }
1055   else
1056     {
1057       // FIXME: This is probably not correct for IRELATIVE relocs.
1058
1059       // For incremental updates, find an available slot.
1060       plt_offset = this->free_list_.allocate(plt_entry_size, plt_entry_size, 0);
1061       if (plt_offset == -1)
1062         gold_fallback(_("out of patch space (PLT);"
1063                         " relink with --incremental-full"));
1064
1065       // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset
1066       // can be calculated from the PLT index, adjusting for the three
1067       // reserved entries at the beginning of the GOT.
1068       plt_index = plt_offset / plt_entry_size - 1;
1069       got_offset = (plt_index - offset + reserved) * 8;
1070     }
1071
1072   gsym->set_plt_offset(plt_offset);
1073
1074   // Every PLT entry needs a reloc.
1075   this->add_relocation(symtab, layout, gsym, got_offset);
1076
1077   // Note that we don't need to save the symbol.  The contents of the
1078   // PLT are independent of which symbols are used.  The symbols only
1079   // appear in the relocations.
1080 }
1081
1082 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.  Return
1083 // the PLT offset.
1084
1085 template<int size>
1086 unsigned int
1087 Output_data_plt_x86_64<size>::add_local_ifunc_entry(
1088     Symbol_table* symtab,
1089     Layout* layout,
1090     Sized_relobj_file<size, false>* relobj,
1091     unsigned int local_sym_index)
1092 {
1093   unsigned int plt_offset = this->irelative_count_ * plt_entry_size;
1094   ++this->irelative_count_;
1095
1096   section_offset_type got_offset = this->got_irelative_->current_data_size();
1097
1098   // Every PLT entry needs a GOT entry which points back to the PLT
1099   // entry.
1100   this->got_irelative_->set_current_data_size(got_offset + 8);
1101
1102   // Every PLT entry needs a reloc.
1103   Reloc_section* rela = this->rela_irelative(symtab, layout);
1104   rela->add_symbolless_local_addend(relobj, local_sym_index,
1105                                     elfcpp::R_X86_64_IRELATIVE,
1106                                     this->got_irelative_, got_offset, 0);
1107
1108   return plt_offset;
1109 }
1110
1111 // Add the relocation for a PLT entry.
1112
1113 template<int size>
1114 void
1115 Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab,
1116                                              Layout* layout,
1117                                              Symbol* gsym,
1118                                              unsigned int got_offset)
1119 {
1120   if (gsym->type() == elfcpp::STT_GNU_IFUNC
1121       && gsym->can_use_relative_reloc(false))
1122     {
1123       Reloc_section* rela = this->rela_irelative(symtab, layout);
1124       rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
1125                                          this->got_irelative_, got_offset, 0);
1126     }
1127   else
1128     {
1129       gsym->set_needs_dynsym_entry();
1130       this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
1131                              got_offset, 0);
1132     }
1133 }
1134
1135 // Return where the TLSDESC relocations should go, creating it if
1136 // necessary.  These follow the JUMP_SLOT relocations.
1137
1138 template<int size>
1139 typename Output_data_plt_x86_64<size>::Reloc_section*
1140 Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout)
1141 {
1142   if (this->tlsdesc_rel_ == NULL)
1143     {
1144       this->tlsdesc_rel_ = new Reloc_section(false);
1145       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1146                                       elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
1147                                       ORDER_DYNAMIC_PLT_RELOCS, false);
1148       gold_assert(this->tlsdesc_rel_->output_section()
1149                   == this->rel_->output_section());
1150     }
1151   return this->tlsdesc_rel_;
1152 }
1153
1154 // Return where the IRELATIVE relocations should go in the PLT.  These
1155 // follow the JUMP_SLOT and the TLSDESC relocations.
1156
1157 template<int size>
1158 typename Output_data_plt_x86_64<size>::Reloc_section*
1159 Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab,
1160                                              Layout* layout)
1161 {
1162   if (this->irelative_rel_ == NULL)
1163     {
1164       // Make sure we have a place for the TLSDESC relocations, in
1165       // case we see any later on.
1166       this->rela_tlsdesc(layout);
1167       this->irelative_rel_ = new Reloc_section(false);
1168       layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
1169                                       elfcpp::SHF_ALLOC, this->irelative_rel_,
1170                                       ORDER_DYNAMIC_PLT_RELOCS, false);
1171       gold_assert(this->irelative_rel_->output_section()
1172                   == this->rel_->output_section());
1173
1174       if (parameters->doing_static_link())
1175         {
1176           // A statically linked executable will only have a .rela.plt
1177           // section to hold R_X86_64_IRELATIVE relocs for
1178           // STT_GNU_IFUNC symbols.  The library will use these
1179           // symbols to locate the IRELATIVE relocs at program startup
1180           // time.
1181           symtab->define_in_output_data("__rela_iplt_start", NULL,
1182                                         Symbol_table::PREDEFINED,
1183                                         this->irelative_rel_, 0, 0,
1184                                         elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1185                                         elfcpp::STV_HIDDEN, 0, false, true);
1186           symtab->define_in_output_data("__rela_iplt_end", NULL,
1187                                         Symbol_table::PREDEFINED,
1188                                         this->irelative_rel_, 0, 0,
1189                                         elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
1190                                         elfcpp::STV_HIDDEN, 0, true, true);
1191         }
1192     }
1193   return this->irelative_rel_;
1194 }
1195
1196 // Return the PLT address to use for a global symbol.
1197
1198 template<int size>
1199 uint64_t
1200 Output_data_plt_x86_64<size>::address_for_global(const Symbol* gsym)
1201 {
1202   uint64_t offset = 0;
1203   if (gsym->type() == elfcpp::STT_GNU_IFUNC
1204       && gsym->can_use_relative_reloc(false))
1205     offset = (this->count_ + 1) * plt_entry_size;
1206   return this->address() + offset;
1207 }
1208
1209 // Return the PLT address to use for a local symbol.  These are always
1210 // IRELATIVE relocs.
1211
1212 template<int size>
1213 uint64_t
1214 Output_data_plt_x86_64<size>::address_for_local(const Relobj*, unsigned int)
1215 {
1216   return this->address() + (this->count_ + 1) * plt_entry_size;
1217 }
1218
1219 // Set the final size.
1220 template<int size>
1221 void
1222 Output_data_plt_x86_64<size>::set_final_data_size()
1223 {
1224   unsigned int count = this->count_ + this->irelative_count_;
1225   if (this->has_tlsdesc_entry())
1226     ++count;
1227   this->set_data_size((count + 1) * plt_entry_size);
1228 }
1229
1230 // The first entry in the PLT for an executable.
1231
1232 template<int size>
1233 const unsigned char
1234 Output_data_plt_x86_64<size>::first_plt_entry[plt_entry_size] =
1235 {
1236   // From AMD64 ABI Draft 0.98, page 76
1237   0xff, 0x35,   // pushq contents of memory address
1238   0, 0, 0, 0,   // replaced with address of .got + 8
1239   0xff, 0x25,   // jmp indirect
1240   0, 0, 0, 0,   // replaced with address of .got + 16
1241   0x90, 0x90, 0x90, 0x90   // noop (x4)
1242 };
1243
1244 // Subsequent entries in the PLT for an executable.
1245
1246 template<int size>
1247 const unsigned char
1248 Output_data_plt_x86_64<size>::plt_entry[plt_entry_size] =
1249 {
1250   // From AMD64 ABI Draft 0.98, page 76
1251   0xff, 0x25,   // jmpq indirect
1252   0, 0, 0, 0,   // replaced with address of symbol in .got
1253   0x68,         // pushq immediate
1254   0, 0, 0, 0,   // replaced with offset into relocation table
1255   0xe9,         // jmpq relative
1256   0, 0, 0, 0    // replaced with offset to start of .plt
1257 };
1258
1259 // The reserved TLSDESC entry in the PLT for an executable.
1260
1261 template<int size>
1262 const unsigned char
1263 Output_data_plt_x86_64<size>::tlsdesc_plt_entry[plt_entry_size] =
1264 {
1265   // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
1266   // and AMD64/EM64T", Version 0.9.4 (2005-10-10).
1267   0xff, 0x35,   // pushq x(%rip)
1268   0, 0, 0, 0,   // replaced with address of linkmap GOT entry (at PLTGOT + 8)
1269   0xff, 0x25,   // jmpq *y(%rip)
1270   0, 0, 0, 0,   // replaced with offset of reserved TLSDESC_GOT entry
1271   0x0f, 0x1f,   // nop
1272   0x40, 0
1273 };
1274
1275 // The .eh_frame unwind information for the PLT.
1276
1277 template<int size>
1278 const unsigned char
1279 Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] =
1280 {
1281   1,                            // CIE version.
1282   'z',                          // Augmentation: augmentation size included.
1283   'R',                          // Augmentation: FDE encoding included.
1284   '\0',                         // End of augmentation string.
1285   1,                            // Code alignment factor.
1286   0x78,                         // Data alignment factor.
1287   16,                           // Return address column.
1288   1,                            // Augmentation size.
1289   (elfcpp::DW_EH_PE_pcrel       // FDE encoding.
1290    | elfcpp::DW_EH_PE_sdata4),
1291   elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8.
1292   elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8.
1293   elfcpp::DW_CFA_nop,           // Align to 16 bytes.
1294   elfcpp::DW_CFA_nop
1295 };
1296
1297 template<int size>
1298 const unsigned char
1299 Output_data_plt_x86_64<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] =
1300 {
1301   0, 0, 0, 0,                           // Replaced with offset to .plt.
1302   0, 0, 0, 0,                           // Replaced with size of .plt.
1303   0,                                    // Augmentation size.
1304   elfcpp::DW_CFA_def_cfa_offset, 16,    // DW_CFA_def_cfa_offset: 16.
1305   elfcpp::DW_CFA_advance_loc + 6,       // Advance 6 to __PLT__ + 6.
1306   elfcpp::DW_CFA_def_cfa_offset, 24,    // DW_CFA_def_cfa_offset: 24.
1307   elfcpp::DW_CFA_advance_loc + 10,      // Advance 10 to __PLT__ + 16.
1308   elfcpp::DW_CFA_def_cfa_expression,    // DW_CFA_def_cfa_expression.
1309   11,                                   // Block length.
1310   elfcpp::DW_OP_breg7, 8,               // Push %rsp + 8.
1311   elfcpp::DW_OP_breg16, 0,              // Push %rip.
1312   elfcpp::DW_OP_lit15,                  // Push 0xf.
1313   elfcpp::DW_OP_and,                    // & (%rip & 0xf).
1314   elfcpp::DW_OP_lit11,                  // Push 0xb.
1315   elfcpp::DW_OP_ge,                     // >= ((%rip & 0xf) >= 0xb)
1316   elfcpp::DW_OP_lit3,                   // Push 3.
1317   elfcpp::DW_OP_shl,                    // << (((%rip & 0xf) >= 0xb) << 3)
1318   elfcpp::DW_OP_plus,                   // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8
1319   elfcpp::DW_CFA_nop,                   // Align to 32 bytes.
1320   elfcpp::DW_CFA_nop,
1321   elfcpp::DW_CFA_nop,
1322   elfcpp::DW_CFA_nop
1323 };
1324
1325 // Write out the PLT.  This uses the hand-coded instructions above,
1326 // and adjusts them as needed.  This is specified by the AMD64 ABI.
1327
1328 template<int size>
1329 void
1330 Output_data_plt_x86_64<size>::do_write(Output_file* of)
1331 {
1332   const off_t offset = this->offset();
1333   const section_size_type oview_size =
1334     convert_to_section_size_type(this->data_size());
1335   unsigned char* const oview = of->get_output_view(offset, oview_size);
1336
1337   const off_t got_file_offset = this->got_plt_->offset();
1338   gold_assert(parameters->incremental_update()
1339               || (got_file_offset + this->got_plt_->data_size()
1340                   == this->got_irelative_->offset()));
1341   const section_size_type got_size =
1342     convert_to_section_size_type(this->got_plt_->data_size()
1343                                  + this->got_irelative_->data_size());
1344   unsigned char* const got_view = of->get_output_view(got_file_offset,
1345                                                       got_size);
1346
1347   unsigned char* pov = oview;
1348
1349   // The base address of the .plt section.
1350   typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address();
1351   // The base address of the .got section.
1352   typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address();
1353   // The base address of the PLT portion of the .got section,
1354   // which is where the GOT pointer will point, and where the
1355   // three reserved GOT entries are located.
1356   typename elfcpp::Elf_types<size>::Elf_Addr got_address
1357     = this->got_plt_->address();
1358
1359   memcpy(pov, first_plt_entry, plt_entry_size);
1360   // We do a jmp relative to the PC at the end of this instruction.
1361   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1362                                               (got_address + 8
1363                                                - (plt_address + 6)));
1364   elfcpp::Swap<32, false>::writeval(pov + 8,
1365                                     (got_address + 16
1366                                      - (plt_address + 12)));
1367   pov += plt_entry_size;
1368
1369   unsigned char* got_pov = got_view;
1370
1371   // The first entry in the GOT is the address of the .dynamic section
1372   // aka the PT_DYNAMIC segment.  The next two entries are reserved.
1373   // We saved space for them when we created the section in
1374   // Target_x86_64::got_section.
1375   Output_section* dynamic = this->layout_->dynamic_section();
1376   uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
1377   elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr);
1378   got_pov += 8;
1379   memset(got_pov, 0, 16);
1380   got_pov += 16;
1381
1382   unsigned int plt_offset = plt_entry_size;
1383   unsigned int got_offset = 24;
1384   const unsigned int count = this->count_ + this->irelative_count_;
1385   for (unsigned int plt_index = 0;
1386        plt_index < count;
1387        ++plt_index,
1388          pov += plt_entry_size,
1389          got_pov += 8,
1390          plt_offset += plt_entry_size,
1391          got_offset += 8)
1392     {
1393       // Set and adjust the PLT entry itself.
1394       memcpy(pov, plt_entry, plt_entry_size);
1395       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1396                                                   (got_address + got_offset
1397                                                    - (plt_address + plt_offset
1398                                                       + 6)));
1399
1400       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
1401       elfcpp::Swap<32, false>::writeval(pov + 12,
1402                                         - (plt_offset + plt_entry_size));
1403
1404       // Set the entry in the GOT.
1405       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
1406     }
1407
1408   if (this->has_tlsdesc_entry())
1409     {
1410       // Set and adjust the reserved TLSDESC PLT entry.
1411       unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
1412       memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
1413       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
1414                                                   (got_address + 8
1415                                                    - (plt_address + plt_offset
1416                                                       + 6)));
1417       elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
1418                                                   (got_base
1419                                                    + tlsdesc_got_offset
1420                                                    - (plt_address + plt_offset
1421                                                       + 12)));
1422       pov += plt_entry_size;
1423     }
1424
1425   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
1426   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
1427
1428   of->write_output_view(offset, oview_size, oview);
1429   of->write_output_view(got_file_offset, got_size, got_view);
1430 }
1431
1432 // Create the PLT section.
1433
1434 template<int size>
1435 void
1436 Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout)
1437 {
1438   if (this->plt_ == NULL)
1439     {
1440       // Create the GOT sections first.
1441       this->got_section(symtab, layout);
1442
1443       this->plt_ = new Output_data_plt_x86_64<size>(layout, this->got_,
1444                                                     this->got_plt_,
1445                                                     this->got_irelative_);
1446       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1447                                       (elfcpp::SHF_ALLOC
1448                                        | elfcpp::SHF_EXECINSTR),
1449                                       this->plt_, ORDER_PLT, false);
1450
1451       // Make the sh_info field of .rela.plt point to .plt.
1452       Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1453       rela_plt_os->set_info_section(this->plt_->output_section());
1454     }
1455 }
1456
1457 // Return the section for TLSDESC relocations.
1458
1459 template<int size>
1460 typename Target_x86_64<size>::Reloc_section*
1461 Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const
1462 {
1463   return this->plt_section()->rela_tlsdesc(layout);
1464 }
1465
1466 // Create a PLT entry for a global symbol.
1467
1468 template<int size>
1469 void
1470 Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout,
1471                                     Symbol* gsym)
1472 {
1473   if (gsym->has_plt_offset())
1474     return;
1475
1476   if (this->plt_ == NULL)
1477     this->make_plt_section(symtab, layout);
1478
1479   this->plt_->add_entry(symtab, layout, gsym);
1480 }
1481
1482 // Make a PLT entry for a local STT_GNU_IFUNC symbol.
1483
1484 template<int size>
1485 void
1486 Target_x86_64<size>::make_local_ifunc_plt_entry(
1487     Symbol_table* symtab, Layout* layout,
1488     Sized_relobj_file<size, false>* relobj,
1489     unsigned int local_sym_index)
1490 {
1491   if (relobj->local_has_plt_offset(local_sym_index))
1492     return;
1493   if (this->plt_ == NULL)
1494     this->make_plt_section(symtab, layout);
1495   unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
1496                                                               relobj,
1497                                                               local_sym_index);
1498   relobj->set_local_plt_offset(local_sym_index, plt_offset);
1499 }
1500
1501 // Return the number of entries in the PLT.
1502
1503 template<int size>
1504 unsigned int
1505 Target_x86_64<size>::plt_entry_count() const
1506 {
1507   if (this->plt_ == NULL)
1508     return 0;
1509   return this->plt_->entry_count();
1510 }
1511
1512 // Return the offset of the first non-reserved PLT entry.
1513
1514 template<int size>
1515 unsigned int
1516 Target_x86_64<size>::first_plt_entry_offset() const
1517 {
1518   return Output_data_plt_x86_64<size>::first_plt_entry_offset();
1519 }
1520
1521 // Return the size of each PLT entry.
1522
1523 template<int size>
1524 unsigned int
1525 Target_x86_64<size>::plt_entry_size() const
1526 {
1527   return Output_data_plt_x86_64<size>::get_plt_entry_size();
1528 }
1529
1530 // Create the GOT and PLT sections for an incremental update.
1531
1532 template<int size>
1533 Output_data_got_base*
1534 Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab,
1535                                        Layout* layout,
1536                                        unsigned int got_count,
1537                                        unsigned int plt_count)
1538 {
1539   gold_assert(this->got_ == NULL);
1540
1541   this->got_ = new Output_data_got<64, false>(got_count * 8);
1542   layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
1543                                   (elfcpp::SHF_ALLOC
1544                                    | elfcpp::SHF_WRITE),
1545                                   this->got_, ORDER_RELRO_LAST,
1546                                   true);
1547
1548   // Add the three reserved entries.
1549   this->got_plt_ = new Output_data_space((plt_count + 3) * 8, 8, "** GOT PLT");
1550   layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1551                                   (elfcpp::SHF_ALLOC
1552                                    | elfcpp::SHF_WRITE),
1553                                   this->got_plt_, ORDER_NON_RELRO_FIRST,
1554                                   false);
1555
1556   // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
1557   this->global_offset_table_ =
1558     symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
1559                                   Symbol_table::PREDEFINED,
1560                                   this->got_plt_,
1561                                   0, 0, elfcpp::STT_OBJECT,
1562                                   elfcpp::STB_LOCAL,
1563                                   elfcpp::STV_HIDDEN, 0,
1564                                   false, false);
1565
1566   // If there are any TLSDESC relocations, they get GOT entries in
1567   // .got.plt after the jump slot entries.
1568   // FIXME: Get the count for TLSDESC entries.
1569   this->got_tlsdesc_ = new Output_data_got<64, false>(0);
1570   layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1571                                   elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1572                                   this->got_tlsdesc_,
1573                                   ORDER_NON_RELRO_FIRST, false);
1574
1575   // If there are any IRELATIVE relocations, they get GOT entries in
1576   // .got.plt after the jump slot and TLSDESC entries.
1577   this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT");
1578   layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
1579                                   elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
1580                                   this->got_irelative_,
1581                                   ORDER_NON_RELRO_FIRST, false);
1582
1583   // Create the PLT section.
1584   this->plt_ = new Output_data_plt_x86_64<size>(layout, this->got_,
1585                                                 this->got_plt_,
1586                                                 this->got_irelative_,
1587                                                 plt_count);
1588   layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
1589                                   elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR,
1590                                   this->plt_, ORDER_PLT, false);
1591
1592   // Make the sh_info field of .rela.plt point to .plt.
1593   Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
1594   rela_plt_os->set_info_section(this->plt_->output_section());
1595
1596   // Create the rela_dyn section.
1597   this->rela_dyn_section(layout);
1598
1599   return this->got_;
1600 }
1601
1602 // Reserve a GOT entry for a local symbol, and regenerate any
1603 // necessary dynamic relocations.
1604
1605 template<int size>
1606 void
1607 Target_x86_64<size>::reserve_local_got_entry(
1608     unsigned int got_index,
1609     Sized_relobj<size, false>* obj,
1610     unsigned int r_sym,
1611     unsigned int got_type)
1612 {
1613   unsigned int got_offset = got_index * 8;
1614   Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1615
1616   this->got_->reserve_local(got_index, obj, r_sym, got_type);
1617   switch (got_type)
1618     {
1619     case GOT_TYPE_STANDARD:
1620       if (parameters->options().output_is_position_independent())
1621         rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
1622                                      this->got_, got_offset, 0, false);
1623       break;
1624     case GOT_TYPE_TLS_OFFSET:
1625       rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
1626                           this->got_, got_offset, 0);
1627       break;
1628     case GOT_TYPE_TLS_PAIR:
1629       this->got_->reserve_slot(got_index + 1);
1630       rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64,
1631                           this->got_, got_offset, 0);
1632       break;
1633     case GOT_TYPE_TLS_DESC:
1634       gold_fatal(_("TLS_DESC not yet supported for incremental linking"));
1635       // this->got_->reserve_slot(got_index + 1);
1636       // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
1637       //                               this->got_, got_offset, 0);
1638       break;
1639     default:
1640       gold_unreachable();
1641     }
1642 }
1643
1644 // Reserve a GOT entry for a global symbol, and regenerate any
1645 // necessary dynamic relocations.
1646
1647 template<int size>
1648 void
1649 Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index,
1650                                               Symbol* gsym,
1651                                               unsigned int got_type)
1652 {
1653   unsigned int got_offset = got_index * 8;
1654   Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
1655
1656   this->got_->reserve_global(got_index, gsym, got_type);
1657   switch (got_type)
1658     {
1659     case GOT_TYPE_STANDARD:
1660       if (!gsym->final_value_is_known())
1661         {
1662           if (gsym->is_from_dynobj()
1663               || gsym->is_undefined()
1664               || gsym->is_preemptible()
1665               || gsym->type() == elfcpp::STT_GNU_IFUNC)
1666             rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT,
1667                                  this->got_, got_offset, 0);
1668           else
1669             rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1670                                           this->got_, got_offset, 0);
1671         }
1672       break;
1673     case GOT_TYPE_TLS_OFFSET:
1674       rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64,
1675                                     this->got_, got_offset, 0);
1676       break;
1677     case GOT_TYPE_TLS_PAIR:
1678       this->got_->reserve_slot(got_index + 1);
1679       rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64,
1680                                     this->got_, got_offset, 0);
1681       rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64,
1682                                     this->got_, got_offset + 8, 0);
1683       break;
1684     case GOT_TYPE_TLS_DESC:
1685       this->got_->reserve_slot(got_index + 1);
1686       rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC,
1687                                     this->got_, got_offset, 0);
1688       break;
1689     default:
1690       gold_unreachable();
1691     }
1692 }
1693
1694 // Register an existing PLT entry for a global symbol.
1695
1696 template<int size>
1697 void
1698 Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab,
1699                                                Layout* layout,
1700                                                unsigned int plt_index,
1701                                                Symbol* gsym)
1702 {
1703   gold_assert(this->plt_ != NULL);
1704   gold_assert(!gsym->has_plt_offset());
1705
1706   this->plt_->reserve_slot(plt_index);
1707
1708   gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
1709
1710   unsigned int got_offset = (plt_index + 3) * 8;
1711   this->plt_->add_relocation(symtab, layout, gsym, got_offset);
1712 }
1713
1714 // Force a COPY relocation for a given symbol.
1715
1716 template<int size>
1717 void
1718 Target_x86_64<size>::emit_copy_reloc(
1719     Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset)
1720 {
1721   this->copy_relocs_.emit_copy_reloc(symtab,
1722                                      symtab->get_sized_symbol<size>(sym),
1723                                      os,
1724                                      offset,
1725                                      this->rela_dyn_section(NULL));
1726 }
1727
1728 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
1729
1730 template<int size>
1731 void
1732 Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab,
1733                                             Layout* layout)
1734 {
1735   if (this->tls_base_symbol_defined_)
1736     return;
1737
1738   Output_segment* tls_segment = layout->tls_segment();
1739   if (tls_segment != NULL)
1740     {
1741       bool is_exec = parameters->options().output_is_executable();
1742       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
1743                                        Symbol_table::PREDEFINED,
1744                                        tls_segment, 0, 0,
1745                                        elfcpp::STT_TLS,
1746                                        elfcpp::STB_LOCAL,
1747                                        elfcpp::STV_HIDDEN, 0,
1748                                        (is_exec
1749                                         ? Symbol::SEGMENT_END
1750                                         : Symbol::SEGMENT_START),
1751                                        true);
1752     }
1753   this->tls_base_symbol_defined_ = true;
1754 }
1755
1756 // Create the reserved PLT and GOT entries for the TLS descriptor resolver.
1757
1758 template<int size>
1759 void
1760 Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab,
1761                                              Layout* layout)
1762 {
1763   if (this->plt_ == NULL)
1764     this->make_plt_section(symtab, layout);
1765
1766   if (!this->plt_->has_tlsdesc_entry())
1767     {
1768       // Allocate the TLSDESC_GOT entry.
1769       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1770       unsigned int got_offset = got->add_constant(0);
1771
1772       // Allocate the TLSDESC_PLT entry.
1773       this->plt_->reserve_tlsdesc_entry(got_offset);
1774     }
1775 }
1776
1777 // Create a GOT entry for the TLS module index.
1778
1779 template<int size>
1780 unsigned int
1781 Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
1782                                          Sized_relobj_file<size, false>* object)
1783 {
1784   if (this->got_mod_index_offset_ == -1U)
1785     {
1786       gold_assert(symtab != NULL && layout != NULL && object != NULL);
1787       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1788       Output_data_got<64, false>* got = this->got_section(symtab, layout);
1789       unsigned int got_offset = got->add_constant(0);
1790       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
1791                           got_offset, 0);
1792       got->add_constant(0);
1793       this->got_mod_index_offset_ = got_offset;
1794     }
1795   return this->got_mod_index_offset_;
1796 }
1797
1798 // Optimize the TLS relocation type based on what we know about the
1799 // symbol.  IS_FINAL is true if the final address of this symbol is
1800 // known at link time.
1801
1802 template<int size>
1803 tls::Tls_optimization
1804 Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type)
1805 {
1806   // If we are generating a shared library, then we can't do anything
1807   // in the linker.
1808   if (parameters->options().shared())
1809     return tls::TLSOPT_NONE;
1810
1811   switch (r_type)
1812     {
1813     case elfcpp::R_X86_64_TLSGD:
1814     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1815     case elfcpp::R_X86_64_TLSDESC_CALL:
1816       // These are General-Dynamic which permits fully general TLS
1817       // access.  Since we know that we are generating an executable,
1818       // we can convert this to Initial-Exec.  If we also know that
1819       // this is a local symbol, we can further switch to Local-Exec.
1820       if (is_final)
1821         return tls::TLSOPT_TO_LE;
1822       return tls::TLSOPT_TO_IE;
1823
1824     case elfcpp::R_X86_64_TLSLD:
1825       // This is Local-Dynamic, which refers to a local symbol in the
1826       // dynamic TLS block.  Since we know that we generating an
1827       // executable, we can switch to Local-Exec.
1828       return tls::TLSOPT_TO_LE;
1829
1830     case elfcpp::R_X86_64_DTPOFF32:
1831     case elfcpp::R_X86_64_DTPOFF64:
1832       // Another Local-Dynamic reloc.
1833       return tls::TLSOPT_TO_LE;
1834
1835     case elfcpp::R_X86_64_GOTTPOFF:
1836       // These are Initial-Exec relocs which get the thread offset
1837       // from the GOT.  If we know that we are linking against the
1838       // local symbol, we can switch to Local-Exec, which links the
1839       // thread offset into the instruction.
1840       if (is_final)
1841         return tls::TLSOPT_TO_LE;
1842       return tls::TLSOPT_NONE;
1843
1844     case elfcpp::R_X86_64_TPOFF32:
1845       // When we already have Local-Exec, there is nothing further we
1846       // can do.
1847       return tls::TLSOPT_NONE;
1848
1849     default:
1850       gold_unreachable();
1851     }
1852 }
1853
1854 // Get the Reference_flags for a particular relocation.
1855
1856 template<int size>
1857 int
1858 Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type)
1859 {
1860   switch (r_type)
1861     {
1862     case elfcpp::R_X86_64_NONE:
1863     case elfcpp::R_X86_64_GNU_VTINHERIT:
1864     case elfcpp::R_X86_64_GNU_VTENTRY:
1865     case elfcpp::R_X86_64_GOTPC32:
1866     case elfcpp::R_X86_64_GOTPC64:
1867       // No symbol reference.
1868       return 0;
1869
1870     case elfcpp::R_X86_64_64:
1871     case elfcpp::R_X86_64_32:
1872     case elfcpp::R_X86_64_32S:
1873     case elfcpp::R_X86_64_16:
1874     case elfcpp::R_X86_64_8:
1875       return Symbol::ABSOLUTE_REF;
1876
1877     case elfcpp::R_X86_64_PC64:
1878     case elfcpp::R_X86_64_PC32:
1879     case elfcpp::R_X86_64_PC16:
1880     case elfcpp::R_X86_64_PC8:
1881     case elfcpp::R_X86_64_GOTOFF64:
1882       return Symbol::RELATIVE_REF;
1883
1884     case elfcpp::R_X86_64_PLT32:
1885     case elfcpp::R_X86_64_PLTOFF64:
1886       return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
1887
1888     case elfcpp::R_X86_64_GOT64:
1889     case elfcpp::R_X86_64_GOT32:
1890     case elfcpp::R_X86_64_GOTPCREL64:
1891     case elfcpp::R_X86_64_GOTPCREL:
1892     case elfcpp::R_X86_64_GOTPLT64:
1893       // Absolute in GOT.
1894       return Symbol::ABSOLUTE_REF;
1895
1896     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1897     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1898     case elfcpp::R_X86_64_TLSDESC_CALL:
1899     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1900     case elfcpp::R_X86_64_DTPOFF32:
1901     case elfcpp::R_X86_64_DTPOFF64:
1902     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1903     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1904       return Symbol::TLS_REF;
1905
1906     case elfcpp::R_X86_64_COPY:
1907     case elfcpp::R_X86_64_GLOB_DAT:
1908     case elfcpp::R_X86_64_JUMP_SLOT:
1909     case elfcpp::R_X86_64_RELATIVE:
1910     case elfcpp::R_X86_64_IRELATIVE:
1911     case elfcpp::R_X86_64_TPOFF64:
1912     case elfcpp::R_X86_64_DTPMOD64:
1913     case elfcpp::R_X86_64_TLSDESC:
1914     case elfcpp::R_X86_64_SIZE32:
1915     case elfcpp::R_X86_64_SIZE64:
1916     default:
1917       // Not expected.  We will give an error later.
1918       return 0;
1919     }
1920 }
1921
1922 // Report an unsupported relocation against a local symbol.
1923
1924 template<int size>
1925 void
1926 Target_x86_64<size>::Scan::unsupported_reloc_local(
1927      Sized_relobj_file<size, false>* object,
1928      unsigned int r_type)
1929 {
1930   gold_error(_("%s: unsupported reloc %u against local symbol"),
1931              object->name().c_str(), r_type);
1932 }
1933
1934 // We are about to emit a dynamic relocation of type R_TYPE.  If the
1935 // dynamic linker does not support it, issue an error.  The GNU linker
1936 // only issues a non-PIC error for an allocated read-only section.
1937 // Here we know the section is allocated, but we don't know that it is
1938 // read-only.  But we check for all the relocation types which the
1939 // glibc dynamic linker supports, so it seems appropriate to issue an
1940 // error even if the section is not read-only.  If GSYM is not NULL,
1941 // it is the symbol the relocation is against; if it is NULL, the
1942 // relocation is against a local symbol.
1943
1944 template<int size>
1945 void
1946 Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type,
1947                                          Symbol* gsym)
1948 {
1949   switch (r_type)
1950     {
1951       // These are the relocation types supported by glibc for x86_64
1952       // which should always work.
1953     case elfcpp::R_X86_64_RELATIVE:
1954     case elfcpp::R_X86_64_IRELATIVE:
1955     case elfcpp::R_X86_64_GLOB_DAT:
1956     case elfcpp::R_X86_64_JUMP_SLOT:
1957     case elfcpp::R_X86_64_DTPMOD64:
1958     case elfcpp::R_X86_64_DTPOFF64:
1959     case elfcpp::R_X86_64_TPOFF64:
1960     case elfcpp::R_X86_64_64:
1961     case elfcpp::R_X86_64_COPY:
1962       return;
1963
1964       // glibc supports these reloc types, but they can overflow.
1965     case elfcpp::R_X86_64_PC32:
1966       // A PC relative reference is OK against a local symbol or if
1967       // the symbol is defined locally.
1968       if (gsym == NULL
1969           || (!gsym->is_from_dynobj()
1970               && !gsym->is_undefined()
1971               && !gsym->is_preemptible()))
1972         return;
1973       /* Fall through.  */
1974     case elfcpp::R_X86_64_32:
1975       // R_X86_64_32 is OK for x32.
1976       if (size == 32 && r_type == elfcpp::R_X86_64_32)
1977         return;
1978       if (this->issued_non_pic_error_)
1979         return;
1980       gold_assert(parameters->options().output_is_position_independent());
1981       if (gsym == NULL)
1982         object->error(_("requires dynamic R_X86_64_32 reloc which may "
1983                         "overflow at runtime; recompile with -fPIC"));
1984       else
1985         object->error(_("requires dynamic %s reloc against '%s' which may "
1986                         "overflow at runtime; recompile with -fPIC"),
1987                       (r_type == elfcpp::R_X86_64_32
1988                        ? "R_X86_64_32"
1989                        : "R_X86_64_PC32"),
1990                       gsym->name());
1991       this->issued_non_pic_error_ = true;
1992       return;
1993
1994     default:
1995       // This prevents us from issuing more than one error per reloc
1996       // section.  But we can still wind up issuing more than one
1997       // error per object file.
1998       if (this->issued_non_pic_error_)
1999         return;
2000       gold_assert(parameters->options().output_is_position_independent());
2001       object->error(_("requires unsupported dynamic reloc %u; "
2002                       "recompile with -fPIC"),
2003                     r_type);
2004       this->issued_non_pic_error_ = true;
2005       return;
2006
2007     case elfcpp::R_X86_64_NONE:
2008       gold_unreachable();
2009     }
2010 }
2011
2012 // Return whether we need to make a PLT entry for a relocation of the
2013 // given type against a STT_GNU_IFUNC symbol.
2014
2015 template<int size>
2016 bool
2017 Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc(
2018      Sized_relobj_file<size, false>* object,
2019      unsigned int r_type)
2020 {
2021   int flags = Scan::get_reference_flags(r_type);
2022   if (flags & Symbol::TLS_REF)
2023     gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
2024                object->name().c_str(), r_type);
2025   return flags != 0;
2026 }
2027
2028 // Scan a relocation for a local symbol.
2029
2030 template<int size>
2031 inline void
2032 Target_x86_64<size>::Scan::local(Symbol_table* symtab,
2033                                  Layout* layout,
2034                                  Target_x86_64<size>* target,
2035                                  Sized_relobj_file<size, false>* object,
2036                                  unsigned int data_shndx,
2037                                  Output_section* output_section,
2038                                  const elfcpp::Rela<size, false>& reloc,
2039                                  unsigned int r_type,
2040                                  const elfcpp::Sym<size, false>& lsym)
2041 {
2042   // A local STT_GNU_IFUNC symbol may require a PLT entry.
2043   bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
2044   if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
2045     {
2046       unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2047       target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
2048     }
2049
2050   switch (r_type)
2051     {
2052     case elfcpp::R_X86_64_NONE:
2053     case elfcpp::R_X86_64_GNU_VTINHERIT:
2054     case elfcpp::R_X86_64_GNU_VTENTRY:
2055       break;
2056
2057     case elfcpp::R_X86_64_64:
2058       // If building a shared library (or a position-independent
2059       // executable), we need to create a dynamic relocation for this
2060       // location.  The relocation applied at link time will apply the
2061       // link-time value, so we flag the location with an
2062       // R_X86_64_RELATIVE relocation so the dynamic loader can
2063       // relocate it easily.
2064       if (parameters->options().output_is_position_independent())
2065         {
2066           unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2067           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2068           rela_dyn->add_local_relative(object, r_sym,
2069                                        elfcpp::R_X86_64_RELATIVE,
2070                                        output_section, data_shndx,
2071                                        reloc.get_r_offset(),
2072                                        reloc.get_r_addend(), is_ifunc);
2073         }
2074       break;
2075
2076     case elfcpp::R_X86_64_32:
2077     case elfcpp::R_X86_64_32S:
2078     case elfcpp::R_X86_64_16:
2079     case elfcpp::R_X86_64_8:
2080       // If building a shared library (or a position-independent
2081       // executable), we need to create a dynamic relocation for this
2082       // location.  We can't use an R_X86_64_RELATIVE relocation
2083       // because that is always a 64-bit relocation.
2084       if (parameters->options().output_is_position_independent())
2085         {
2086           // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32.
2087           if (size == 32 && r_type == elfcpp::R_X86_64_32)
2088             {
2089               unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2090               Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2091               rela_dyn->add_local_relative(object, r_sym,
2092                                            elfcpp::R_X86_64_RELATIVE,
2093                                            output_section, data_shndx,
2094                                            reloc.get_r_offset(),
2095                                            reloc.get_r_addend(), is_ifunc);
2096               break;
2097             }
2098
2099           this->check_non_pic(object, r_type, NULL);
2100
2101           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2102           unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2103           if (lsym.get_st_type() != elfcpp::STT_SECTION)
2104             rela_dyn->add_local(object, r_sym, r_type, output_section,
2105                                 data_shndx, reloc.get_r_offset(),
2106                                 reloc.get_r_addend());
2107           else
2108             {
2109               gold_assert(lsym.get_st_value() == 0);
2110               unsigned int shndx = lsym.get_st_shndx();
2111               bool is_ordinary;
2112               shndx = object->adjust_sym_shndx(r_sym, shndx,
2113                                                &is_ordinary);
2114               if (!is_ordinary)
2115                 object->error(_("section symbol %u has bad shndx %u"),
2116                               r_sym, shndx);
2117               else
2118                 rela_dyn->add_local_section(object, shndx,
2119                                             r_type, output_section,
2120                                             data_shndx, reloc.get_r_offset(),
2121                                             reloc.get_r_addend());
2122             }
2123         }
2124       break;
2125
2126     case elfcpp::R_X86_64_PC64:
2127     case elfcpp::R_X86_64_PC32:
2128     case elfcpp::R_X86_64_PC16:
2129     case elfcpp::R_X86_64_PC8:
2130       break;
2131
2132     case elfcpp::R_X86_64_PLT32:
2133       // Since we know this is a local symbol, we can handle this as a
2134       // PC32 reloc.
2135       break;
2136
2137     case elfcpp::R_X86_64_GOTPC32:
2138     case elfcpp::R_X86_64_GOTOFF64:
2139     case elfcpp::R_X86_64_GOTPC64:
2140     case elfcpp::R_X86_64_PLTOFF64:
2141       // We need a GOT section.
2142       target->got_section(symtab, layout);
2143       // For PLTOFF64, we'd normally want a PLT section, but since we
2144       // know this is a local symbol, no PLT is needed.
2145       break;
2146
2147     case elfcpp::R_X86_64_GOT64:
2148     case elfcpp::R_X86_64_GOT32:
2149     case elfcpp::R_X86_64_GOTPCREL64:
2150     case elfcpp::R_X86_64_GOTPCREL:
2151     case elfcpp::R_X86_64_GOTPLT64:
2152       {
2153         // The symbol requires a GOT entry.
2154         Output_data_got<64, false>* got = target->got_section(symtab, layout);
2155         unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2156
2157         // For a STT_GNU_IFUNC symbol we want the PLT offset.  That
2158         // lets function pointers compare correctly with shared
2159         // libraries.  Otherwise we would need an IRELATIVE reloc.
2160         bool is_new;
2161         if (is_ifunc)
2162           is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
2163         else
2164           is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
2165         if (is_new)
2166           {
2167             // If we are generating a shared object, we need to add a
2168             // dynamic relocation for this symbol's GOT entry.
2169             if (parameters->options().output_is_position_independent())
2170               {
2171                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2172                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
2173                 if (r_type != elfcpp::R_X86_64_GOT32)
2174                   {
2175                     unsigned int got_offset =
2176                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
2177                     rela_dyn->add_local_relative(object, r_sym,
2178                                                  elfcpp::R_X86_64_RELATIVE,
2179                                                  got, got_offset, 0, is_ifunc);
2180                   }
2181                 else
2182                   {
2183                     this->check_non_pic(object, r_type, NULL);
2184
2185                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
2186                     rela_dyn->add_local(
2187                         object, r_sym, r_type, got,
2188                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
2189                   }
2190               }
2191           }
2192         // For GOTPLT64, we'd normally want a PLT section, but since
2193         // we know this is a local symbol, no PLT is needed.
2194       }
2195       break;
2196
2197     case elfcpp::R_X86_64_COPY:
2198     case elfcpp::R_X86_64_GLOB_DAT:
2199     case elfcpp::R_X86_64_JUMP_SLOT:
2200     case elfcpp::R_X86_64_RELATIVE:
2201     case elfcpp::R_X86_64_IRELATIVE:
2202       // These are outstanding tls relocs, which are unexpected when linking
2203     case elfcpp::R_X86_64_TPOFF64:
2204     case elfcpp::R_X86_64_DTPMOD64:
2205     case elfcpp::R_X86_64_TLSDESC:
2206       gold_error(_("%s: unexpected reloc %u in object file"),
2207                  object->name().c_str(), r_type);
2208       break;
2209
2210       // These are initial tls relocs, which are expected when linking
2211     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2212     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2213     case elfcpp::R_X86_64_TLSDESC_CALL:
2214     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2215     case elfcpp::R_X86_64_DTPOFF32:
2216     case elfcpp::R_X86_64_DTPOFF64:
2217     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2218     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2219       {
2220         bool output_is_shared = parameters->options().shared();
2221         const tls::Tls_optimization optimized_type
2222             = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared,
2223                                                       r_type);
2224         switch (r_type)
2225           {
2226           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
2227             if (optimized_type == tls::TLSOPT_NONE)
2228               {
2229                 // Create a pair of GOT entries for the module index and
2230                 // dtv-relative offset.
2231                 Output_data_got<64, false>* got
2232                     = target->got_section(symtab, layout);
2233                 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2234                 unsigned int shndx = lsym.get_st_shndx();
2235                 bool is_ordinary;
2236                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
2237                 if (!is_ordinary)
2238                   object->error(_("local symbol %u has bad shndx %u"),
2239                               r_sym, shndx);
2240                 else
2241                   got->add_local_pair_with_rel(object, r_sym,
2242                                                shndx,
2243                                                GOT_TYPE_TLS_PAIR,
2244                                                target->rela_dyn_section(layout),
2245                                                elfcpp::R_X86_64_DTPMOD64, 0);
2246               }
2247             else if (optimized_type != tls::TLSOPT_TO_LE)
2248               unsupported_reloc_local(object, r_type);
2249             break;
2250
2251           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2252             target->define_tls_base_symbol(symtab, layout);
2253             if (optimized_type == tls::TLSOPT_NONE)
2254               {
2255                 // Create reserved PLT and GOT entries for the resolver.
2256                 target->reserve_tlsdesc_entries(symtab, layout);
2257
2258                 // Generate a double GOT entry with an
2259                 // R_X86_64_TLSDESC reloc.  The R_X86_64_TLSDESC reloc
2260                 // is resolved lazily, so the GOT entry needs to be in
2261                 // an area in .got.plt, not .got.  Call got_section to
2262                 // make sure the section has been created.
2263                 target->got_section(symtab, layout);
2264                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2265                 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2266                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
2267                   {
2268                     unsigned int got_offset = got->add_constant(0);
2269                     got->add_constant(0);
2270                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
2271                                                  got_offset);
2272                     Reloc_section* rt = target->rela_tlsdesc_section(layout);
2273                     // We store the arguments we need in a vector, and
2274                     // use the index into the vector as the parameter
2275                     // to pass to the target specific routines.
2276                     uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
2277                     void* arg = reinterpret_cast<void*>(intarg);
2278                     rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
2279                                             got, got_offset, 0);
2280                   }
2281               }
2282             else if (optimized_type != tls::TLSOPT_TO_LE)
2283               unsupported_reloc_local(object, r_type);
2284             break;
2285
2286           case elfcpp::R_X86_64_TLSDESC_CALL:
2287             break;
2288
2289           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
2290             if (optimized_type == tls::TLSOPT_NONE)
2291               {
2292                 // Create a GOT entry for the module index.
2293                 target->got_mod_index_entry(symtab, layout, object);
2294               }
2295             else if (optimized_type != tls::TLSOPT_TO_LE)
2296               unsupported_reloc_local(object, r_type);
2297             break;
2298
2299           case elfcpp::R_X86_64_DTPOFF32:
2300           case elfcpp::R_X86_64_DTPOFF64:
2301             break;
2302
2303           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
2304             layout->set_has_static_tls();
2305             if (optimized_type == tls::TLSOPT_NONE)
2306               {
2307                 // Create a GOT entry for the tp-relative offset.
2308                 Output_data_got<64, false>* got
2309                     = target->got_section(symtab, layout);
2310                 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info());
2311                 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET,
2312                                         target->rela_dyn_section(layout),
2313                                         elfcpp::R_X86_64_TPOFF64);
2314               }
2315             else if (optimized_type != tls::TLSOPT_TO_LE)
2316               unsupported_reloc_local(object, r_type);
2317             break;
2318
2319           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
2320             layout->set_has_static_tls();
2321             if (output_is_shared)
2322               unsupported_reloc_local(object, r_type);
2323             break;
2324
2325           default:
2326             gold_unreachable();
2327           }
2328       }
2329       break;
2330
2331     case elfcpp::R_X86_64_SIZE32:
2332     case elfcpp::R_X86_64_SIZE64:
2333     default:
2334       gold_error(_("%s: unsupported reloc %u against local symbol"),
2335                  object->name().c_str(), r_type);
2336       break;
2337     }
2338 }
2339
2340
2341 // Report an unsupported relocation against a global symbol.
2342
2343 template<int size>
2344 void
2345 Target_x86_64<size>::Scan::unsupported_reloc_global(
2346     Sized_relobj_file<size, false>* object,
2347     unsigned int r_type,
2348     Symbol* gsym)
2349 {
2350   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2351              object->name().c_str(), r_type, gsym->demangled_name().c_str());
2352 }
2353
2354 // Returns true if this relocation type could be that of a function pointer.
2355 template<int size>
2356 inline bool
2357 Target_x86_64<size>::Scan::possible_function_pointer_reloc(unsigned int r_type)
2358 {
2359   switch (r_type)
2360     {
2361     case elfcpp::R_X86_64_64:
2362     case elfcpp::R_X86_64_32:
2363     case elfcpp::R_X86_64_32S:
2364     case elfcpp::R_X86_64_16:
2365     case elfcpp::R_X86_64_8:
2366     case elfcpp::R_X86_64_GOT64:
2367     case elfcpp::R_X86_64_GOT32:
2368     case elfcpp::R_X86_64_GOTPCREL64:
2369     case elfcpp::R_X86_64_GOTPCREL:
2370     case elfcpp::R_X86_64_GOTPLT64:
2371       {
2372         return true;
2373       }
2374     }
2375   return false;
2376 }
2377
2378 // For safe ICF, scan a relocation for a local symbol to check if it
2379 // corresponds to a function pointer being taken.  In that case mark
2380 // the function whose pointer was taken as not foldable.
2381
2382 template<int size>
2383 inline bool
2384 Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer(
2385   Symbol_table* ,
2386   Layout* ,
2387   Target_x86_64<size>* ,
2388   Sized_relobj_file<size, false>* ,
2389   unsigned int ,
2390   Output_section* ,
2391   const elfcpp::Rela<size, false>& ,
2392   unsigned int r_type,
2393   const elfcpp::Sym<size, false>&)
2394 {
2395   // When building a shared library, do not fold any local symbols as it is
2396   // not possible to distinguish pointer taken versus a call by looking at
2397   // the relocation types.
2398   return (parameters->options().shared()
2399           || possible_function_pointer_reloc(r_type));
2400 }
2401
2402 // For safe ICF, scan a relocation for a global symbol to check if it
2403 // corresponds to a function pointer being taken.  In that case mark
2404 // the function whose pointer was taken as not foldable.
2405
2406 template<int size>
2407 inline bool
2408 Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer(
2409   Symbol_table*,
2410   Layout* ,
2411   Target_x86_64<size>* ,
2412   Sized_relobj_file<size, false>* ,
2413   unsigned int ,
2414   Output_section* ,
2415   const elfcpp::Rela<size, false>& ,
2416   unsigned int r_type,
2417   Symbol* gsym)
2418 {
2419   // When building a shared library, do not fold symbols whose visibility
2420   // is hidden, internal or protected.
2421   return ((parameters->options().shared()
2422            && (gsym->visibility() == elfcpp::STV_INTERNAL
2423                || gsym->visibility() == elfcpp::STV_PROTECTED
2424                || gsym->visibility() == elfcpp::STV_HIDDEN))
2425           || possible_function_pointer_reloc(r_type));
2426 }
2427
2428 // Scan a relocation for a global symbol.
2429
2430 template<int size>
2431 inline void
2432 Target_x86_64<size>::Scan::global(Symbol_table* symtab,
2433                             Layout* layout,
2434                             Target_x86_64<size>* target,
2435                             Sized_relobj_file<size, false>* object,
2436                             unsigned int data_shndx,
2437                             Output_section* output_section,
2438                             const elfcpp::Rela<size, false>& reloc,
2439                             unsigned int r_type,
2440                             Symbol* gsym)
2441 {
2442   // A STT_GNU_IFUNC symbol may require a PLT entry.
2443   if (gsym->type() == elfcpp::STT_GNU_IFUNC
2444       && this->reloc_needs_plt_for_ifunc(object, r_type))
2445     target->make_plt_entry(symtab, layout, gsym);
2446
2447   switch (r_type)
2448     {
2449     case elfcpp::R_X86_64_NONE:
2450     case elfcpp::R_X86_64_GNU_VTINHERIT:
2451     case elfcpp::R_X86_64_GNU_VTENTRY:
2452       break;
2453
2454     case elfcpp::R_X86_64_64:
2455     case elfcpp::R_X86_64_32:
2456     case elfcpp::R_X86_64_32S:
2457     case elfcpp::R_X86_64_16:
2458     case elfcpp::R_X86_64_8:
2459       {
2460         // Make a PLT entry if necessary.
2461         if (gsym->needs_plt_entry())
2462           {
2463             target->make_plt_entry(symtab, layout, gsym);
2464             // Since this is not a PC-relative relocation, we may be
2465             // taking the address of a function. In that case we need to
2466             // set the entry in the dynamic symbol table to the address of
2467             // the PLT entry.
2468             if (gsym->is_from_dynobj() && !parameters->options().shared())
2469               gsym->set_needs_dynsym_value();
2470           }
2471         // Make a dynamic relocation if necessary.
2472         if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2473           {
2474             if (gsym->may_need_copy_reloc())
2475               {
2476                 target->copy_reloc(symtab, layout, object,
2477                                    data_shndx, output_section, gsym, reloc);
2478               }
2479             else if (((size == 64 && r_type == elfcpp::R_X86_64_64)
2480                       || (size == 32 && r_type == elfcpp::R_X86_64_32))
2481                      && gsym->type() == elfcpp::STT_GNU_IFUNC
2482                      && gsym->can_use_relative_reloc(false)
2483                      && !gsym->is_from_dynobj()
2484                      && !gsym->is_undefined()
2485                      && !gsym->is_preemptible())
2486               {
2487                 // Use an IRELATIVE reloc for a locally defined
2488                 // STT_GNU_IFUNC symbol.  This makes a function
2489                 // address in a PIE executable match the address in a
2490                 // shared library that it links against.
2491                 Reloc_section* rela_dyn =
2492                   target->rela_irelative_section(layout);
2493                 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
2494                 rela_dyn->add_symbolless_global_addend(gsym, r_type,
2495                                                        output_section, object,
2496                                                        data_shndx,
2497                                                        reloc.get_r_offset(),
2498                                                        reloc.get_r_addend());
2499               }
2500             else if (r_type == elfcpp::R_X86_64_64
2501                      && gsym->can_use_relative_reloc(false))
2502               {
2503                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2504                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
2505                                               output_section, object,
2506                                               data_shndx,
2507                                               reloc.get_r_offset(),
2508                                               reloc.get_r_addend());
2509               }
2510             else
2511               {
2512                 this->check_non_pic(object, r_type, gsym);
2513                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2514                 rela_dyn->add_global(gsym, r_type, output_section, object,
2515                                      data_shndx, reloc.get_r_offset(),
2516                                      reloc.get_r_addend());
2517               }
2518           }
2519       }
2520       break;
2521
2522     case elfcpp::R_X86_64_PC64:
2523     case elfcpp::R_X86_64_PC32:
2524     case elfcpp::R_X86_64_PC16:
2525     case elfcpp::R_X86_64_PC8:
2526       {
2527         // Make a PLT entry if necessary.
2528         if (gsym->needs_plt_entry())
2529           target->make_plt_entry(symtab, layout, gsym);
2530         // Make a dynamic relocation if necessary.
2531         if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
2532           {
2533             if (gsym->may_need_copy_reloc())
2534               {
2535                 target->copy_reloc(symtab, layout, object,
2536                                    data_shndx, output_section, gsym, reloc);
2537               }
2538             else
2539               {
2540                 this->check_non_pic(object, r_type, gsym);
2541                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2542                 rela_dyn->add_global(gsym, r_type, output_section, object,
2543                                      data_shndx, reloc.get_r_offset(),
2544                                      reloc.get_r_addend());
2545               }
2546           }
2547       }
2548       break;
2549
2550     case elfcpp::R_X86_64_GOT64:
2551     case elfcpp::R_X86_64_GOT32:
2552     case elfcpp::R_X86_64_GOTPCREL64:
2553     case elfcpp::R_X86_64_GOTPCREL:
2554     case elfcpp::R_X86_64_GOTPLT64:
2555       {
2556         // The symbol requires a GOT entry.
2557         Output_data_got<64, false>* got = target->got_section(symtab, layout);
2558         if (gsym->final_value_is_known())
2559           {
2560             // For a STT_GNU_IFUNC symbol we want the PLT address.
2561             if (gsym->type() == elfcpp::STT_GNU_IFUNC)
2562               got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2563             else
2564               got->add_global(gsym, GOT_TYPE_STANDARD);
2565           }
2566         else
2567           {
2568             // If this symbol is not fully resolved, we need to add a
2569             // dynamic relocation for it.
2570             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
2571
2572             // Use a GLOB_DAT rather than a RELATIVE reloc if:
2573             //
2574             // 1) The symbol may be defined in some other module.
2575             //
2576             // 2) We are building a shared library and this is a
2577             // protected symbol; using GLOB_DAT means that the dynamic
2578             // linker can use the address of the PLT in the main
2579             // executable when appropriate so that function address
2580             // comparisons work.
2581             //
2582             // 3) This is a STT_GNU_IFUNC symbol in position dependent
2583             // code, again so that function address comparisons work.
2584             if (gsym->is_from_dynobj()
2585                 || gsym->is_undefined()
2586                 || gsym->is_preemptible()
2587                 || (gsym->visibility() == elfcpp::STV_PROTECTED
2588                     && parameters->options().shared())
2589                 || (gsym->type() == elfcpp::STT_GNU_IFUNC
2590                     && parameters->options().output_is_position_independent()))
2591               got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn,
2592                                        elfcpp::R_X86_64_GLOB_DAT);
2593             else
2594               {
2595                 // For a STT_GNU_IFUNC symbol we want to write the PLT
2596                 // offset into the GOT, so that function pointer
2597                 // comparisons work correctly.
2598                 bool is_new;
2599                 if (gsym->type() != elfcpp::STT_GNU_IFUNC)
2600                   is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
2601                 else
2602                   {
2603                     is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
2604                     // Tell the dynamic linker to use the PLT address
2605                     // when resolving relocations.
2606                     if (gsym->is_from_dynobj()
2607                         && !parameters->options().shared())
2608                       gsym->set_needs_dynsym_value();
2609                   }
2610                 if (is_new)
2611                   {
2612                     unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
2613                     rela_dyn->add_global_relative(gsym,
2614                                                   elfcpp::R_X86_64_RELATIVE,
2615                                                   got, got_off, 0);
2616                   }
2617               }
2618           }
2619         // For GOTPLT64, we also need a PLT entry (but only if the
2620         // symbol is not fully resolved).
2621         if (r_type == elfcpp::R_X86_64_GOTPLT64
2622             && !gsym->final_value_is_known())
2623           target->make_plt_entry(symtab, layout, gsym);
2624       }
2625       break;
2626
2627     case elfcpp::R_X86_64_PLT32:
2628       // If the symbol is fully resolved, this is just a PC32 reloc.
2629       // Otherwise we need a PLT entry.
2630       if (gsym->final_value_is_known())
2631         break;
2632       // If building a shared library, we can also skip the PLT entry
2633       // if the symbol is defined in the output file and is protected
2634       // or hidden.
2635       if (gsym->is_defined()
2636           && !gsym->is_from_dynobj()
2637           && !gsym->is_preemptible())
2638         break;
2639       target->make_plt_entry(symtab, layout, gsym);
2640       break;
2641
2642     case elfcpp::R_X86_64_GOTPC32:
2643     case elfcpp::R_X86_64_GOTOFF64:
2644     case elfcpp::R_X86_64_GOTPC64:
2645     case elfcpp::R_X86_64_PLTOFF64:
2646       // We need a GOT section.
2647       target->got_section(symtab, layout);
2648       // For PLTOFF64, we also need a PLT entry (but only if the
2649       // symbol is not fully resolved).
2650       if (r_type == elfcpp::R_X86_64_PLTOFF64
2651           && !gsym->final_value_is_known())
2652         target->make_plt_entry(symtab, layout, gsym);
2653       break;
2654
2655     case elfcpp::R_X86_64_COPY:
2656     case elfcpp::R_X86_64_GLOB_DAT:
2657     case elfcpp::R_X86_64_JUMP_SLOT:
2658     case elfcpp::R_X86_64_RELATIVE:
2659     case elfcpp::R_X86_64_IRELATIVE:
2660       // These are outstanding tls relocs, which are unexpected when linking
2661     case elfcpp::R_X86_64_TPOFF64:
2662     case elfcpp::R_X86_64_DTPMOD64:
2663     case elfcpp::R_X86_64_TLSDESC:
2664       gold_error(_("%s: unexpected reloc %u in object file"),
2665                  object->name().c_str(), r_type);
2666       break;
2667
2668       // These are initial tls relocs, which are expected for global()
2669     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2670     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2671     case elfcpp::R_X86_64_TLSDESC_CALL:
2672     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2673     case elfcpp::R_X86_64_DTPOFF32:
2674     case elfcpp::R_X86_64_DTPOFF64:
2675     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2676     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2677       {
2678         const bool is_final = gsym->final_value_is_known();
2679         const tls::Tls_optimization optimized_type
2680             = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
2681         switch (r_type)
2682           {
2683           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
2684             if (optimized_type == tls::TLSOPT_NONE)
2685               {
2686                 // Create a pair of GOT entries for the module index and
2687                 // dtv-relative offset.
2688                 Output_data_got<64, false>* got
2689                     = target->got_section(symtab, layout);
2690                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
2691                                               target->rela_dyn_section(layout),
2692                                               elfcpp::R_X86_64_DTPMOD64,
2693                                               elfcpp::R_X86_64_DTPOFF64);
2694               }
2695             else if (optimized_type == tls::TLSOPT_TO_IE)
2696               {
2697                 // Create a GOT entry for the tp-relative offset.
2698                 Output_data_got<64, false>* got
2699                     = target->got_section(symtab, layout);
2700                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2701                                          target->rela_dyn_section(layout),
2702                                          elfcpp::R_X86_64_TPOFF64);
2703               }
2704             else if (optimized_type != tls::TLSOPT_TO_LE)
2705               unsupported_reloc_global(object, r_type, gsym);
2706             break;
2707
2708           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
2709             target->define_tls_base_symbol(symtab, layout);
2710             if (optimized_type == tls::TLSOPT_NONE)
2711               {
2712                 // Create reserved PLT and GOT entries for the resolver.
2713                 target->reserve_tlsdesc_entries(symtab, layout);
2714
2715                 // Create a double GOT entry with an R_X86_64_TLSDESC
2716                 // reloc.  The R_X86_64_TLSDESC reloc is resolved
2717                 // lazily, so the GOT entry needs to be in an area in
2718                 // .got.plt, not .got.  Call got_section to make sure
2719                 // the section has been created.
2720                 target->got_section(symtab, layout);
2721                 Output_data_got<64, false>* got = target->got_tlsdesc_section();
2722                 Reloc_section* rt = target->rela_tlsdesc_section(layout);
2723                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
2724                                               elfcpp::R_X86_64_TLSDESC, 0);
2725               }
2726             else if (optimized_type == tls::TLSOPT_TO_IE)
2727               {
2728                 // Create a GOT entry for the tp-relative offset.
2729                 Output_data_got<64, false>* got
2730                     = target->got_section(symtab, layout);
2731                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2732                                          target->rela_dyn_section(layout),
2733                                          elfcpp::R_X86_64_TPOFF64);
2734               }
2735             else if (optimized_type != tls::TLSOPT_TO_LE)
2736               unsupported_reloc_global(object, r_type, gsym);
2737             break;
2738
2739           case elfcpp::R_X86_64_TLSDESC_CALL:
2740             break;
2741
2742           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
2743             if (optimized_type == tls::TLSOPT_NONE)
2744               {
2745                 // Create a GOT entry for the module index.
2746                 target->got_mod_index_entry(symtab, layout, object);
2747               }
2748             else if (optimized_type != tls::TLSOPT_TO_LE)
2749               unsupported_reloc_global(object, r_type, gsym);
2750             break;
2751
2752           case elfcpp::R_X86_64_DTPOFF32:
2753           case elfcpp::R_X86_64_DTPOFF64:
2754             break;
2755
2756           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
2757             layout->set_has_static_tls();
2758             if (optimized_type == tls::TLSOPT_NONE)
2759               {
2760                 // Create a GOT entry for the tp-relative offset.
2761                 Output_data_got<64, false>* got
2762                     = target->got_section(symtab, layout);
2763                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET,
2764                                          target->rela_dyn_section(layout),
2765                                          elfcpp::R_X86_64_TPOFF64);
2766               }
2767             else if (optimized_type != tls::TLSOPT_TO_LE)
2768               unsupported_reloc_global(object, r_type, gsym);
2769             break;
2770
2771           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
2772             layout->set_has_static_tls();
2773             if (parameters->options().shared())
2774               unsupported_reloc_local(object, r_type);
2775             break;
2776
2777           default:
2778             gold_unreachable();
2779           }
2780       }
2781       break;
2782
2783     case elfcpp::R_X86_64_SIZE32:
2784     case elfcpp::R_X86_64_SIZE64:
2785     default:
2786       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
2787                  object->name().c_str(), r_type,
2788                  gsym->demangled_name().c_str());
2789       break;
2790     }
2791 }
2792
2793 template<int size>
2794 void
2795 Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab,
2796                                        Layout* layout,
2797                                        Sized_relobj_file<size, false>* object,
2798                                        unsigned int data_shndx,
2799                                        unsigned int sh_type,
2800                                        const unsigned char* prelocs,
2801                                        size_t reloc_count,
2802                                        Output_section* output_section,
2803                                        bool needs_special_offset_handling,
2804                                        size_t local_symbol_count,
2805                                        const unsigned char* plocal_symbols)
2806 {
2807
2808   if (sh_type == elfcpp::SHT_REL)
2809     {
2810       return;
2811     }
2812
2813    gold::gc_process_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
2814                            typename Target_x86_64<size>::Scan,
2815                            typename Target_x86_64<size>::Relocatable_size_for_reloc>(
2816     symtab,
2817     layout,
2818     this,
2819     object,
2820     data_shndx,
2821     prelocs,
2822     reloc_count,
2823     output_section,
2824     needs_special_offset_handling,
2825     local_symbol_count,
2826     plocal_symbols);
2827
2828 }
2829 // Scan relocations for a section.
2830
2831 template<int size>
2832 void
2833 Target_x86_64<size>::scan_relocs(Symbol_table* symtab,
2834                                  Layout* layout,
2835                                  Sized_relobj_file<size, false>* object,
2836                                  unsigned int data_shndx,
2837                                  unsigned int sh_type,
2838                                  const unsigned char* prelocs,
2839                                  size_t reloc_count,
2840                                  Output_section* output_section,
2841                                  bool needs_special_offset_handling,
2842                                  size_t local_symbol_count,
2843                                  const unsigned char* plocal_symbols)
2844 {
2845   if (sh_type == elfcpp::SHT_REL)
2846     {
2847       gold_error(_("%s: unsupported REL reloc section"),
2848                  object->name().c_str());
2849       return;
2850     }
2851
2852   gold::scan_relocs<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
2853       typename Target_x86_64<size>::Scan>(
2854     symtab,
2855     layout,
2856     this,
2857     object,
2858     data_shndx,
2859     prelocs,
2860     reloc_count,
2861     output_section,
2862     needs_special_offset_handling,
2863     local_symbol_count,
2864     plocal_symbols);
2865 }
2866
2867 // Finalize the sections.
2868
2869 template<int size>
2870 void
2871 Target_x86_64<size>::do_finalize_sections(
2872     Layout* layout,
2873     const Input_objects*,
2874     Symbol_table* symtab)
2875 {
2876   const Reloc_section* rel_plt = (this->plt_ == NULL
2877                                   ? NULL
2878                                   : this->plt_->rela_plt());
2879   layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
2880                                   this->rela_dyn_, true, false);
2881
2882   // Fill in some more dynamic tags.
2883   Output_data_dynamic* const odyn = layout->dynamic_data();
2884   if (odyn != NULL)
2885     {
2886       if (this->plt_ != NULL
2887           && this->plt_->output_section() != NULL
2888           && this->plt_->has_tlsdesc_entry())
2889         {
2890           unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
2891           unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
2892           this->got_->finalize_data_size();
2893           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
2894                                         this->plt_, plt_offset);
2895           odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
2896                                         this->got_, got_offset);
2897         }
2898     }
2899
2900   // Emit any relocs we saved in an attempt to avoid generating COPY
2901   // relocs.
2902   if (this->copy_relocs_.any_saved_relocs())
2903     this->copy_relocs_.emit(this->rela_dyn_section(layout));
2904
2905   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
2906   // the .got.plt section.
2907   Symbol* sym = this->global_offset_table_;
2908   if (sym != NULL)
2909     {
2910       uint64_t data_size = this->got_plt_->current_data_size();
2911       symtab->get_sized_symbol<size>(sym)->set_symsize(data_size);
2912     }
2913
2914   if (parameters->doing_static_link()
2915       && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
2916     {
2917       // If linking statically, make sure that the __rela_iplt symbols
2918       // were defined if necessary, even if we didn't create a PLT.
2919       static const Define_symbol_in_segment syms[] =
2920         {
2921           {
2922             "__rela_iplt_start",        // name
2923             elfcpp::PT_LOAD,            // segment_type
2924             elfcpp::PF_W,               // segment_flags_set
2925             elfcpp::PF(0),              // segment_flags_clear
2926             0,                          // value
2927             0,                          // size
2928             elfcpp::STT_NOTYPE,         // type
2929             elfcpp::STB_GLOBAL,         // binding
2930             elfcpp::STV_HIDDEN,         // visibility
2931             0,                          // nonvis
2932             Symbol::SEGMENT_START,      // offset_from_base
2933             true                        // only_if_ref
2934           },
2935           {
2936             "__rela_iplt_end",          // name
2937             elfcpp::PT_LOAD,            // segment_type
2938             elfcpp::PF_W,               // segment_flags_set
2939             elfcpp::PF(0),              // segment_flags_clear
2940             0,                          // value
2941             0,                          // size
2942             elfcpp::STT_NOTYPE,         // type
2943             elfcpp::STB_GLOBAL,         // binding
2944             elfcpp::STV_HIDDEN,         // visibility
2945             0,                          // nonvis
2946             Symbol::SEGMENT_START,      // offset_from_base
2947             true                        // only_if_ref
2948           }
2949         };
2950
2951       symtab->define_symbols(layout, 2, syms,
2952                              layout->script_options()->saw_sections_clause());
2953     }
2954 }
2955
2956 // Perform a relocation.
2957
2958 template<int size>
2959 inline bool
2960 Target_x86_64<size>::Relocate::relocate(
2961     const Relocate_info<size, false>* relinfo,
2962     Target_x86_64<size>* target,
2963     Output_section*,
2964     size_t relnum,
2965     const elfcpp::Rela<size, false>& rela,
2966     unsigned int r_type,
2967     const Sized_symbol<size>* gsym,
2968     const Symbol_value<size>* psymval,
2969     unsigned char* view,
2970     typename elfcpp::Elf_types<size>::Elf_Addr address,
2971     section_size_type view_size)
2972 {
2973   if (this->skip_call_tls_get_addr_)
2974     {
2975       if ((r_type != elfcpp::R_X86_64_PLT32
2976            && r_type != elfcpp::R_X86_64_PC32)
2977           || gsym == NULL
2978           || strcmp(gsym->name(), "__tls_get_addr") != 0)
2979         {
2980           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
2981                                  _("missing expected TLS relocation"));
2982         }
2983       else
2984         {
2985           this->skip_call_tls_get_addr_ = false;
2986           return false;
2987         }
2988     }
2989
2990   const Sized_relobj_file<size, false>* object = relinfo->object;
2991
2992   // Pick the value to use for symbols defined in the PLT.
2993   Symbol_value<size> symval;
2994   if (gsym != NULL
2995       && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
2996     {
2997       symval.set_output_value(target->plt_address_for_global(gsym)
2998                               + gsym->plt_offset());
2999       psymval = &symval;
3000     }
3001   else if (gsym == NULL && psymval->is_ifunc_symbol())
3002     {
3003       unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3004       if (object->local_has_plt_offset(r_sym))
3005         {
3006           symval.set_output_value(target->plt_address_for_local(object, r_sym)
3007                                   + object->local_plt_offset(r_sym));
3008           psymval = &symval;
3009         }
3010     }
3011
3012   const elfcpp::Elf_Xword addend = rela.get_r_addend();
3013
3014   // Get the GOT offset if needed.
3015   // The GOT pointer points to the end of the GOT section.
3016   // We need to subtract the size of the GOT section to get
3017   // the actual offset to use in the relocation.
3018   bool have_got_offset = false;
3019   unsigned int got_offset = 0;
3020   switch (r_type)
3021     {
3022     case elfcpp::R_X86_64_GOT32:
3023     case elfcpp::R_X86_64_GOT64:
3024     case elfcpp::R_X86_64_GOTPLT64:
3025     case elfcpp::R_X86_64_GOTPCREL:
3026     case elfcpp::R_X86_64_GOTPCREL64:
3027       if (gsym != NULL)
3028         {
3029           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
3030           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
3031         }
3032       else
3033         {
3034           unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3035           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
3036           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
3037                         - target->got_size());
3038         }
3039       have_got_offset = true;
3040       break;
3041
3042     default:
3043       break;
3044     }
3045
3046   switch (r_type)
3047     {
3048     case elfcpp::R_X86_64_NONE:
3049     case elfcpp::R_X86_64_GNU_VTINHERIT:
3050     case elfcpp::R_X86_64_GNU_VTENTRY:
3051       break;
3052
3053     case elfcpp::R_X86_64_64:
3054       Relocate_functions<size, false>::rela64(view, object, psymval, addend);
3055       break;
3056
3057     case elfcpp::R_X86_64_PC64:
3058       Relocate_functions<size, false>::pcrela64(view, object, psymval, addend,
3059                                               address);
3060       break;
3061
3062     case elfcpp::R_X86_64_32:
3063       // FIXME: we need to verify that value + addend fits into 32 bits:
3064       //    uint64_t x = value + addend;
3065       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
3066       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
3067       Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3068       break;
3069
3070     case elfcpp::R_X86_64_32S:
3071       // FIXME: we need to verify that value + addend fits into 32 bits:
3072       //    int64_t x = value + addend;   // note this quantity is signed!
3073       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
3074       Relocate_functions<size, false>::rela32(view, object, psymval, addend);
3075       break;
3076
3077     case elfcpp::R_X86_64_PC32:
3078       Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3079                                                 address);
3080       break;
3081
3082     case elfcpp::R_X86_64_16:
3083       Relocate_functions<size, false>::rela16(view, object, psymval, addend);
3084       break;
3085
3086     case elfcpp::R_X86_64_PC16:
3087       Relocate_functions<size, false>::pcrela16(view, object, psymval, addend,
3088                                                 address);
3089       break;
3090
3091     case elfcpp::R_X86_64_8:
3092       Relocate_functions<size, false>::rela8(view, object, psymval, addend);
3093       break;
3094
3095     case elfcpp::R_X86_64_PC8:
3096       Relocate_functions<size, false>::pcrela8(view, object, psymval, addend,
3097                                                address);
3098       break;
3099
3100     case elfcpp::R_X86_64_PLT32:
3101       gold_assert(gsym == NULL
3102                   || gsym->has_plt_offset()
3103                   || gsym->final_value_is_known()
3104                   || (gsym->is_defined()
3105                       && !gsym->is_from_dynobj()
3106                       && !gsym->is_preemptible()));
3107       // Note: while this code looks the same as for R_X86_64_PC32, it
3108       // behaves differently because psymval was set to point to
3109       // the PLT entry, rather than the symbol, in Scan::global().
3110       Relocate_functions<size, false>::pcrela32(view, object, psymval, addend,
3111                                                 address);
3112       break;
3113
3114     case elfcpp::R_X86_64_PLTOFF64:
3115       {
3116         gold_assert(gsym);
3117         gold_assert(gsym->has_plt_offset()
3118                     || gsym->final_value_is_known());
3119         typename elfcpp::Elf_types<size>::Elf_Addr got_address;
3120         got_address = target->got_section(NULL, NULL)->address();
3121         Relocate_functions<size, false>::rela64(view, object, psymval,
3122                                                 addend - got_address);
3123       }
3124
3125     case elfcpp::R_X86_64_GOT32:
3126       gold_assert(have_got_offset);
3127       Relocate_functions<size, false>::rela32(view, got_offset, addend);
3128       break;
3129
3130     case elfcpp::R_X86_64_GOTPC32:
3131       {
3132         gold_assert(gsym);
3133         typename elfcpp::Elf_types<size>::Elf_Addr value;
3134         value = target->got_plt_section()->address();
3135         Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3136       }
3137       break;
3138
3139     case elfcpp::R_X86_64_GOT64:
3140       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
3141       // Since we always add a PLT entry, this is equivalent.
3142     case elfcpp::R_X86_64_GOTPLT64:
3143       gold_assert(have_got_offset);
3144       Relocate_functions<size, false>::rela64(view, got_offset, addend);
3145       break;
3146
3147     case elfcpp::R_X86_64_GOTPC64:
3148       {
3149         gold_assert(gsym);
3150         typename elfcpp::Elf_types<size>::Elf_Addr value;
3151         value = target->got_plt_section()->address();
3152         Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3153       }
3154       break;
3155
3156     case elfcpp::R_X86_64_GOTOFF64:
3157       {
3158         typename elfcpp::Elf_types<size>::Elf_Addr value;
3159         value = (psymval->value(object, 0)
3160                  - target->got_plt_section()->address());
3161         Relocate_functions<size, false>::rela64(view, value, addend);
3162       }
3163       break;
3164
3165     case elfcpp::R_X86_64_GOTPCREL:
3166       {
3167         gold_assert(have_got_offset);
3168         typename elfcpp::Elf_types<size>::Elf_Addr value;
3169         value = target->got_plt_section()->address() + got_offset;
3170         Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3171       }
3172       break;
3173
3174     case elfcpp::R_X86_64_GOTPCREL64:
3175       {
3176         gold_assert(have_got_offset);
3177         typename elfcpp::Elf_types<size>::Elf_Addr value;
3178         value = target->got_plt_section()->address() + got_offset;
3179         Relocate_functions<size, false>::pcrela64(view, value, addend, address);
3180       }
3181       break;
3182
3183     case elfcpp::R_X86_64_COPY:
3184     case elfcpp::R_X86_64_GLOB_DAT:
3185     case elfcpp::R_X86_64_JUMP_SLOT:
3186     case elfcpp::R_X86_64_RELATIVE:
3187     case elfcpp::R_X86_64_IRELATIVE:
3188       // These are outstanding tls relocs, which are unexpected when linking
3189     case elfcpp::R_X86_64_TPOFF64:
3190     case elfcpp::R_X86_64_DTPMOD64:
3191     case elfcpp::R_X86_64_TLSDESC:
3192       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3193                              _("unexpected reloc %u in object file"),
3194                              r_type);
3195       break;
3196
3197       // These are initial tls relocs, which are expected when linking
3198     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
3199     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
3200     case elfcpp::R_X86_64_TLSDESC_CALL:
3201     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
3202     case elfcpp::R_X86_64_DTPOFF32:
3203     case elfcpp::R_X86_64_DTPOFF64:
3204     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
3205     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
3206       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
3207                          view, address, view_size);
3208       break;
3209
3210     case elfcpp::R_X86_64_SIZE32:
3211     case elfcpp::R_X86_64_SIZE64:
3212     default:
3213       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3214                              _("unsupported reloc %u"),
3215                              r_type);
3216       break;
3217     }
3218
3219   return true;
3220 }
3221
3222 // Perform a TLS relocation.
3223
3224 template<int size>
3225 inline void
3226 Target_x86_64<size>::Relocate::relocate_tls(
3227     const Relocate_info<size, false>* relinfo,
3228     Target_x86_64<size>* target,
3229     size_t relnum,
3230     const elfcpp::Rela<size, false>& rela,
3231     unsigned int r_type,
3232     const Sized_symbol<size>* gsym,
3233     const Symbol_value<size>* psymval,
3234     unsigned char* view,
3235     typename elfcpp::Elf_types<size>::Elf_Addr address,
3236     section_size_type view_size)
3237 {
3238   Output_segment* tls_segment = relinfo->layout->tls_segment();
3239
3240   const Sized_relobj_file<size, false>* object = relinfo->object;
3241   const elfcpp::Elf_Xword addend = rela.get_r_addend();
3242   elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr);
3243   bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
3244
3245   typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0);
3246
3247   const bool is_final = (gsym == NULL
3248                          ? !parameters->options().shared()
3249                          : gsym->final_value_is_known());
3250   tls::Tls_optimization optimized_type
3251       = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type);
3252   switch (r_type)
3253     {
3254     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
3255       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3256         {
3257           // If this code sequence is used in a non-executable section,
3258           // we will not optimize the R_X86_64_DTPOFF32/64 relocation,
3259           // on the assumption that it's being used by itself in a debug
3260           // section.  Therefore, in the unlikely event that the code
3261           // sequence appears in a non-executable section, we simply
3262           // leave it unoptimized.
3263           optimized_type = tls::TLSOPT_NONE;
3264         }
3265       if (optimized_type == tls::TLSOPT_TO_LE)
3266         {
3267           if (tls_segment == NULL)
3268             {
3269               gold_assert(parameters->errors()->error_count() > 0
3270                           || issue_undefined_symbol_error(gsym));
3271               return;
3272             }
3273           this->tls_gd_to_le(relinfo, relnum, tls_segment,
3274                              rela, r_type, value, view,
3275                              view_size);
3276           break;
3277         }
3278       else
3279         {
3280           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3281                                    ? GOT_TYPE_TLS_OFFSET
3282                                    : GOT_TYPE_TLS_PAIR);
3283           unsigned int got_offset;
3284           if (gsym != NULL)
3285             {
3286               gold_assert(gsym->has_got_offset(got_type));
3287               got_offset = gsym->got_offset(got_type) - target->got_size();
3288             }
3289           else
3290             {
3291               unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3292               gold_assert(object->local_has_got_offset(r_sym, got_type));
3293               got_offset = (object->local_got_offset(r_sym, got_type)
3294                             - target->got_size());
3295             }
3296           if (optimized_type == tls::TLSOPT_TO_IE)
3297             {
3298               value = target->got_plt_section()->address() + got_offset;
3299               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
3300                                  value, view, address, view_size);
3301               break;
3302             }
3303           else if (optimized_type == tls::TLSOPT_NONE)
3304             {
3305               // Relocate the field with the offset of the pair of GOT
3306               // entries.
3307               value = target->got_plt_section()->address() + got_offset;
3308               Relocate_functions<size, false>::pcrela32(view, value, addend,
3309                                                         address);
3310               break;
3311             }
3312         }
3313       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3314                              _("unsupported reloc %u"), r_type);
3315       break;
3316
3317     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
3318     case elfcpp::R_X86_64_TLSDESC_CALL:
3319       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3320         {
3321           // See above comment for R_X86_64_TLSGD.
3322           optimized_type = tls::TLSOPT_NONE;
3323         }
3324       if (optimized_type == tls::TLSOPT_TO_LE)
3325         {
3326           if (tls_segment == NULL)
3327             {
3328               gold_assert(parameters->errors()->error_count() > 0
3329                           || issue_undefined_symbol_error(gsym));
3330               return;
3331             }
3332           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
3333                                   rela, r_type, value, view,
3334                                   view_size);
3335           break;
3336         }
3337       else
3338         {
3339           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
3340                                    ? GOT_TYPE_TLS_OFFSET
3341                                    : GOT_TYPE_TLS_DESC);
3342           unsigned int got_offset = 0;
3343           if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
3344               && optimized_type == tls::TLSOPT_NONE)
3345             {
3346               // We created GOT entries in the .got.tlsdesc portion of
3347               // the .got.plt section, but the offset stored in the
3348               // symbol is the offset within .got.tlsdesc.
3349               got_offset = (target->got_size()
3350                             + target->got_plt_section()->data_size());
3351             }
3352           if (gsym != NULL)
3353             {
3354               gold_assert(gsym->has_got_offset(got_type));
3355               got_offset += gsym->got_offset(got_type) - target->got_size();
3356             }
3357           else
3358             {
3359               unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3360               gold_assert(object->local_has_got_offset(r_sym, got_type));
3361               got_offset += (object->local_got_offset(r_sym, got_type)
3362                              - target->got_size());
3363             }
3364           if (optimized_type == tls::TLSOPT_TO_IE)
3365             {
3366               if (tls_segment == NULL)
3367                 {
3368                   gold_assert(parameters->errors()->error_count() > 0
3369                               || issue_undefined_symbol_error(gsym));
3370                   return;
3371                 }
3372               value = target->got_plt_section()->address() + got_offset;
3373               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
3374                                       rela, r_type, value, view, address,
3375                                       view_size);
3376               break;
3377             }
3378           else if (optimized_type == tls::TLSOPT_NONE)
3379             {
3380               if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3381                 {
3382                   // Relocate the field with the offset of the pair of GOT
3383                   // entries.
3384                   value = target->got_plt_section()->address() + got_offset;
3385                   Relocate_functions<size, false>::pcrela32(view, value, addend,
3386                                                             address);
3387                 }
3388               break;
3389             }
3390         }
3391       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3392                              _("unsupported reloc %u"), r_type);
3393       break;
3394
3395     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
3396       if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
3397         {
3398           // See above comment for R_X86_64_TLSGD.
3399           optimized_type = tls::TLSOPT_NONE;
3400         }
3401       if (optimized_type == tls::TLSOPT_TO_LE)
3402         {
3403           if (tls_segment == NULL)
3404             {
3405               gold_assert(parameters->errors()->error_count() > 0
3406                           || issue_undefined_symbol_error(gsym));
3407               return;
3408             }
3409           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
3410                              value, view, view_size);
3411           break;
3412         }
3413       else if (optimized_type == tls::TLSOPT_NONE)
3414         {
3415           // Relocate the field with the offset of the GOT entry for
3416           // the module index.
3417           unsigned int got_offset;
3418           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
3419                         - target->got_size());
3420           value = target->got_plt_section()->address() + got_offset;
3421           Relocate_functions<size, false>::pcrela32(view, value, addend,
3422                                                     address);
3423           break;
3424         }
3425       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3426                              _("unsupported reloc %u"), r_type);
3427       break;
3428
3429     case elfcpp::R_X86_64_DTPOFF32:
3430       // This relocation type is used in debugging information.
3431       // In that case we need to not optimize the value.  If the
3432       // section is not executable, then we assume we should not
3433       // optimize this reloc.  See comments above for R_X86_64_TLSGD,
3434       // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
3435       // R_X86_64_TLSLD.
3436       if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3437         {
3438           if (tls_segment == NULL)
3439             {
3440               gold_assert(parameters->errors()->error_count() > 0
3441                           || issue_undefined_symbol_error(gsym));
3442               return;
3443             }
3444           value -= tls_segment->memsz();
3445         }
3446       Relocate_functions<size, false>::rela32(view, value, addend);
3447       break;
3448
3449     case elfcpp::R_X86_64_DTPOFF64:
3450       // See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
3451       if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
3452         {
3453           if (tls_segment == NULL)
3454             {
3455               gold_assert(parameters->errors()->error_count() > 0
3456                           || issue_undefined_symbol_error(gsym));
3457               return;
3458             }
3459           value -= tls_segment->memsz();
3460         }
3461       Relocate_functions<size, false>::rela64(view, value, addend);
3462       break;
3463
3464     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
3465       if (optimized_type == tls::TLSOPT_TO_LE)
3466         {
3467           if (tls_segment == NULL)
3468             {
3469               gold_assert(parameters->errors()->error_count() > 0
3470                           || issue_undefined_symbol_error(gsym));
3471               return;
3472             }
3473           Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum,
3474                                                       tls_segment, rela,
3475                                                       r_type, value, view,
3476                                                       view_size);
3477           break;
3478         }
3479       else if (optimized_type == tls::TLSOPT_NONE)
3480         {
3481           // Relocate the field with the offset of the GOT entry for
3482           // the tp-relative offset of the symbol.
3483           unsigned int got_offset;
3484           if (gsym != NULL)
3485             {
3486               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
3487               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
3488                             - target->got_size());
3489             }
3490           else
3491             {
3492               unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info());
3493               gold_assert(object->local_has_got_offset(r_sym,
3494                                                        GOT_TYPE_TLS_OFFSET));
3495               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
3496                             - target->got_size());
3497             }
3498           value = target->got_plt_section()->address() + got_offset;
3499           Relocate_functions<size, false>::pcrela32(view, value, addend,
3500                                                     address);
3501           break;
3502         }
3503       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
3504                              _("unsupported reloc type %u"),
3505                              r_type);
3506       break;
3507
3508     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
3509       if (tls_segment == NULL)
3510         {
3511           gold_assert(parameters->errors()->error_count() > 0
3512                       || issue_undefined_symbol_error(gsym));
3513           return;
3514         }
3515       value -= tls_segment->memsz();
3516       Relocate_functions<size, false>::rela32(view, value, addend);
3517       break;
3518     }
3519 }
3520
3521 // Do a relocation in which we convert a TLS General-Dynamic to an
3522 // Initial-Exec.
3523
3524 template<int size>
3525 inline void
3526 Target_x86_64<size>::Relocate::tls_gd_to_ie(
3527     const Relocate_info<size, false>* relinfo,
3528     size_t relnum,
3529     Output_segment*,
3530     const elfcpp::Rela<size, false>& rela,
3531     unsigned int,
3532     typename elfcpp::Elf_types<size>::Elf_Addr value,
3533     unsigned char* view,
3534     typename elfcpp::Elf_types<size>::Elf_Addr address,
3535     section_size_type view_size)
3536 {
3537   // For SIZE == 64:
3538   //    .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3539   //    .word 0x6666; rex64; call __tls_get_addr
3540   //    ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
3541   // For SIZE == 32:
3542   //    leaq foo@tlsgd(%rip),%rdi;
3543   //    .word 0x6666; rex64; call __tls_get_addr
3544   //    ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax
3545
3546   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3547   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3548                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3549
3550   if (size == 64)
3551     {
3552       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3553                        -4);
3554       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3555                      (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3556       memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
3557              16);
3558     }
3559   else
3560     {
3561       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3562                        -3);
3563       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3564                      (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
3565       memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0",
3566              15);
3567     }
3568
3569   const elfcpp::Elf_Xword addend = rela.get_r_addend();
3570   Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8,
3571                                             address);
3572
3573   // The next reloc should be a PLT32 reloc against __tls_get_addr.
3574   // We can skip it.
3575   this->skip_call_tls_get_addr_ = true;
3576 }
3577
3578 // Do a relocation in which we convert a TLS General-Dynamic to a
3579 // Local-Exec.
3580
3581 template<int size>
3582 inline void
3583 Target_x86_64<size>::Relocate::tls_gd_to_le(
3584     const Relocate_info<size, false>* relinfo,
3585     size_t relnum,
3586     Output_segment* tls_segment,
3587     const elfcpp::Rela<size, false>& rela,
3588     unsigned int,
3589     typename elfcpp::Elf_types<size>::Elf_Addr value,
3590     unsigned char* view,
3591     section_size_type view_size)
3592 {
3593   // For SIZE == 64:
3594   //    .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
3595   //    .word 0x6666; rex64; call __tls_get_addr
3596   //    ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
3597   // For SIZE == 32:
3598   //    leaq foo@tlsgd(%rip),%rdi;
3599   //    .word 0x6666; rex64; call __tls_get_addr
3600   //    ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax
3601
3602   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
3603   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3604                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
3605
3606   if (size == 64)
3607     {
3608       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3609                        -4);
3610       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3611                      (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
3612       memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
3613              16);
3614     }
3615   else
3616     {
3617       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size,
3618                        -3);
3619       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3620                      (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0));
3621
3622       memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0",
3623              15);
3624     }
3625
3626   value -= tls_segment->memsz();
3627   Relocate_functions<size, false>::rela32(view + 8, value, 0);
3628
3629   // The next reloc should be a PLT32 reloc against __tls_get_addr.
3630   // We can skip it.
3631   this->skip_call_tls_get_addr_ = true;
3632 }
3633
3634 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
3635
3636 template<int size>
3637 inline void
3638 Target_x86_64<size>::Relocate::tls_desc_gd_to_ie(
3639     const Relocate_info<size, false>* relinfo,
3640     size_t relnum,
3641     Output_segment*,
3642     const elfcpp::Rela<size, false>& rela,
3643     unsigned int r_type,
3644     typename elfcpp::Elf_types<size>::Elf_Addr value,
3645     unsigned char* view,
3646     typename elfcpp::Elf_types<size>::Elf_Addr address,
3647     section_size_type view_size)
3648 {
3649   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3650     {
3651       // leaq foo@tlsdesc(%rip), %rax
3652       // ==> movq foo@gottpoff(%rip), %rax
3653       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3654       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3655       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3656                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3657       view[-2] = 0x8b;
3658       const elfcpp::Elf_Xword addend = rela.get_r_addend();
3659       Relocate_functions<size, false>::pcrela32(view, value, addend, address);
3660     }
3661   else
3662     {
3663       // call *foo@tlscall(%rax)
3664       // ==> nop; nop
3665       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3666       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3667       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3668                      view[0] == 0xff && view[1] == 0x10);
3669       view[0] = 0x66;
3670       view[1] = 0x90;
3671     }
3672 }
3673
3674 // Do a TLSDESC-style General-Dynamic to Local-Exec transition.
3675
3676 template<int size>
3677 inline void
3678 Target_x86_64<size>::Relocate::tls_desc_gd_to_le(
3679     const Relocate_info<size, false>* relinfo,
3680     size_t relnum,
3681     Output_segment* tls_segment,
3682     const elfcpp::Rela<size, false>& rela,
3683     unsigned int r_type,
3684     typename elfcpp::Elf_types<size>::Elf_Addr value,
3685     unsigned char* view,
3686     section_size_type view_size)
3687 {
3688   if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
3689     {
3690       // leaq foo@tlsdesc(%rip), %rax
3691       // ==> movq foo@tpoff, %rax
3692       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3693       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3694       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3695                      view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
3696       view[-2] = 0xc7;
3697       view[-1] = 0xc0;
3698       value -= tls_segment->memsz();
3699       Relocate_functions<size, false>::rela32(view, value, 0);
3700     }
3701   else
3702     {
3703       // call *foo@tlscall(%rax)
3704       // ==> nop; nop
3705       gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
3706       tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
3707       tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3708                      view[0] == 0xff && view[1] == 0x10);
3709       view[0] = 0x66;
3710       view[1] = 0x90;
3711     }
3712 }
3713
3714 template<int size>
3715 inline void
3716 Target_x86_64<size>::Relocate::tls_ld_to_le(
3717     const Relocate_info<size, false>* relinfo,
3718     size_t relnum,
3719     Output_segment*,
3720     const elfcpp::Rela<size, false>& rela,
3721     unsigned int,
3722     typename elfcpp::Elf_types<size>::Elf_Addr,
3723     unsigned char* view,
3724     section_size_type view_size)
3725 {
3726   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
3727   // ... leq foo@dtpoff(%rax),%reg
3728   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
3729
3730   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3731   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
3732
3733   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
3734                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
3735
3736   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
3737
3738   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
3739
3740   // The next reloc should be a PLT32 reloc against __tls_get_addr.
3741   // We can skip it.
3742   this->skip_call_tls_get_addr_ = true;
3743 }
3744
3745 // Do a relocation in which we convert a TLS Initial-Exec to a
3746 // Local-Exec.
3747
3748 template<int size>
3749 inline void
3750 Target_x86_64<size>::Relocate::tls_ie_to_le(
3751     const Relocate_info<size, false>* relinfo,
3752     size_t relnum,
3753     Output_segment* tls_segment,
3754     const elfcpp::Rela<size, false>& rela,
3755     unsigned int,
3756     typename elfcpp::Elf_types<size>::Elf_Addr value,
3757     unsigned char* view,
3758     section_size_type view_size)
3759 {
3760   // We need to examine the opcodes to figure out which instruction we
3761   // are looking at.
3762
3763   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
3764   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
3765
3766   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
3767   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
3768
3769   unsigned char op1 = view[-3];
3770   unsigned char op2 = view[-2];
3771   unsigned char op3 = view[-1];
3772   unsigned char reg = op3 >> 3;
3773
3774   if (op2 == 0x8b)
3775     {
3776       // movq
3777       if (op1 == 0x4c)
3778         view[-3] = 0x49;
3779       view[-2] = 0xc7;
3780       view[-1] = 0xc0 | reg;
3781     }
3782   else if (reg == 4)
3783     {
3784       // Special handling for %rsp.
3785       if (op1 == 0x4c)
3786         view[-3] = 0x49;
3787       view[-2] = 0x81;
3788       view[-1] = 0xc0 | reg;
3789     }
3790   else
3791     {
3792       // addq
3793       if (op1 == 0x4c)
3794         view[-3] = 0x4d;
3795       view[-2] = 0x8d;
3796       view[-1] = 0x80 | reg | (reg << 3);
3797     }
3798
3799   value -= tls_segment->memsz();
3800   Relocate_functions<size, false>::rela32(view, value, 0);
3801 }
3802
3803 // Relocate section data.
3804
3805 template<int size>
3806 void
3807 Target_x86_64<size>::relocate_section(
3808     const Relocate_info<size, false>* relinfo,
3809     unsigned int sh_type,
3810     const unsigned char* prelocs,
3811     size_t reloc_count,
3812     Output_section* output_section,
3813     bool needs_special_offset_handling,
3814     unsigned char* view,
3815     typename elfcpp::Elf_types<size>::Elf_Addr address,
3816     section_size_type view_size,
3817     const Reloc_symbol_changes* reloc_symbol_changes)
3818 {
3819   gold_assert(sh_type == elfcpp::SHT_RELA);
3820
3821   gold::relocate_section<size, false, Target_x86_64<size>, elfcpp::SHT_RELA,
3822                          typename Target_x86_64<size>::Relocate>(
3823     relinfo,
3824     this,
3825     prelocs,
3826     reloc_count,
3827     output_section,
3828     needs_special_offset_handling,
3829     view,
3830     address,
3831     view_size,
3832     reloc_symbol_changes);
3833 }
3834
3835 // Apply an incremental relocation.  Incremental relocations always refer
3836 // to global symbols.
3837
3838 template<int size>
3839 void
3840 Target_x86_64<size>::apply_relocation(
3841     const Relocate_info<size, false>* relinfo,
3842     typename elfcpp::Elf_types<size>::Elf_Addr r_offset,
3843     unsigned int r_type,
3844     typename elfcpp::Elf_types<size>::Elf_Swxword r_addend,
3845     const Symbol* gsym,
3846     unsigned char* view,
3847     typename elfcpp::Elf_types<size>::Elf_Addr address,
3848     section_size_type view_size)
3849 {
3850   gold::apply_relocation<size, false, Target_x86_64<size>,
3851                          typename Target_x86_64<size>::Relocate>(
3852     relinfo,
3853     this,
3854     r_offset,
3855     r_type,
3856     r_addend,
3857     gsym,
3858     view,
3859     address,
3860     view_size);
3861 }
3862
3863 // Return the size of a relocation while scanning during a relocatable
3864 // link.
3865
3866 template<int size>
3867 unsigned int
3868 Target_x86_64<size>::Relocatable_size_for_reloc::get_size_for_reloc(
3869     unsigned int r_type,
3870     Relobj* object)
3871 {
3872   switch (r_type)
3873     {
3874     case elfcpp::R_X86_64_NONE:
3875     case elfcpp::R_X86_64_GNU_VTINHERIT:
3876     case elfcpp::R_X86_64_GNU_VTENTRY:
3877     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
3878     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
3879     case elfcpp::R_X86_64_TLSDESC_CALL:
3880     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
3881     case elfcpp::R_X86_64_DTPOFF32:
3882     case elfcpp::R_X86_64_DTPOFF64:
3883     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
3884     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
3885       return 0;
3886
3887     case elfcpp::R_X86_64_64:
3888     case elfcpp::R_X86_64_PC64:
3889     case elfcpp::R_X86_64_GOTOFF64:
3890     case elfcpp::R_X86_64_GOTPC64:
3891     case elfcpp::R_X86_64_PLTOFF64:
3892     case elfcpp::R_X86_64_GOT64:
3893     case elfcpp::R_X86_64_GOTPCREL64:
3894     case elfcpp::R_X86_64_GOTPCREL:
3895     case elfcpp::R_X86_64_GOTPLT64:
3896       return 8;
3897
3898     case elfcpp::R_X86_64_32:
3899     case elfcpp::R_X86_64_32S:
3900     case elfcpp::R_X86_64_PC32:
3901     case elfcpp::R_X86_64_PLT32:
3902     case elfcpp::R_X86_64_GOTPC32:
3903     case elfcpp::R_X86_64_GOT32:
3904       return 4;
3905
3906     case elfcpp::R_X86_64_16:
3907     case elfcpp::R_X86_64_PC16:
3908       return 2;
3909
3910     case elfcpp::R_X86_64_8:
3911     case elfcpp::R_X86_64_PC8:
3912       return 1;
3913
3914     case elfcpp::R_X86_64_COPY:
3915     case elfcpp::R_X86_64_GLOB_DAT:
3916     case elfcpp::R_X86_64_JUMP_SLOT:
3917     case elfcpp::R_X86_64_RELATIVE:
3918     case elfcpp::R_X86_64_IRELATIVE:
3919       // These are outstanding tls relocs, which are unexpected when linking
3920     case elfcpp::R_X86_64_TPOFF64:
3921     case elfcpp::R_X86_64_DTPMOD64:
3922     case elfcpp::R_X86_64_TLSDESC:
3923       object->error(_("unexpected reloc %u in object file"), r_type);
3924       return 0;
3925
3926     case elfcpp::R_X86_64_SIZE32:
3927     case elfcpp::R_X86_64_SIZE64:
3928     default:
3929       object->error(_("unsupported reloc %u against local symbol"), r_type);
3930       return 0;
3931     }
3932 }
3933
3934 // Scan the relocs during a relocatable link.
3935
3936 template<int size>
3937 void
3938 Target_x86_64<size>::scan_relocatable_relocs(
3939     Symbol_table* symtab,
3940     Layout* layout,
3941     Sized_relobj_file<size, false>* object,
3942     unsigned int data_shndx,
3943     unsigned int sh_type,
3944     const unsigned char* prelocs,
3945     size_t reloc_count,
3946     Output_section* output_section,
3947     bool needs_special_offset_handling,
3948     size_t local_symbol_count,
3949     const unsigned char* plocal_symbols,
3950     Relocatable_relocs* rr)
3951 {
3952   gold_assert(sh_type == elfcpp::SHT_RELA);
3953
3954   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
3955     Relocatable_size_for_reloc> Scan_relocatable_relocs;
3956
3957   gold::scan_relocatable_relocs<size, false, elfcpp::SHT_RELA,
3958       Scan_relocatable_relocs>(
3959     symtab,
3960     layout,
3961     object,
3962     data_shndx,
3963     prelocs,
3964     reloc_count,
3965     output_section,
3966     needs_special_offset_handling,
3967     local_symbol_count,
3968     plocal_symbols,
3969     rr);
3970 }
3971
3972 // Relocate a section during a relocatable link.
3973
3974 template<int size>
3975 void
3976 Target_x86_64<size>::relocate_for_relocatable(
3977     const Relocate_info<size, false>* relinfo,
3978     unsigned int sh_type,
3979     const unsigned char* prelocs,
3980     size_t reloc_count,
3981     Output_section* output_section,
3982     off_t offset_in_output_section,
3983     const Relocatable_relocs* rr,
3984     unsigned char* view,
3985     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
3986     section_size_type view_size,
3987     unsigned char* reloc_view,
3988     section_size_type reloc_view_size)
3989 {
3990   gold_assert(sh_type == elfcpp::SHT_RELA);
3991
3992   gold::relocate_for_relocatable<size, false, elfcpp::SHT_RELA>(
3993     relinfo,
3994     prelocs,
3995     reloc_count,
3996     output_section,
3997     offset_in_output_section,
3998     rr,
3999     view,
4000     view_address,
4001     view_size,
4002     reloc_view,
4003     reloc_view_size);
4004 }
4005
4006 // Return the value to use for a dynamic which requires special
4007 // treatment.  This is how we support equality comparisons of function
4008 // pointers across shared library boundaries, as described in the
4009 // processor specific ABI supplement.
4010
4011 template<int size>
4012 uint64_t
4013 Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const
4014 {
4015   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
4016   return this->plt_address_for_global(gsym) + gsym->plt_offset();
4017 }
4018
4019 // Return a string used to fill a code section with nops to take up
4020 // the specified length.
4021
4022 template<int size>
4023 std::string
4024 Target_x86_64<size>::do_code_fill(section_size_type length) const
4025 {
4026   if (length >= 16)
4027     {
4028       // Build a jmpq instruction to skip over the bytes.
4029       unsigned char jmp[5];
4030       jmp[0] = 0xe9;
4031       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
4032       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
4033               + std::string(length - 5, static_cast<char>(0x90)));
4034     }
4035
4036   // Nop sequences of various lengths.
4037   const char nop1[1] = { '\x90' };                 // nop
4038   const char nop2[2] = { '\x66', '\x90' };         // xchg %ax %ax
4039   const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax)
4040   const char nop4[4] = { '\x0f', '\x1f', '\x40',   // nop 0(%rax)
4041                          '\x00'};
4042   const char nop5[5] = { '\x0f', '\x1f', '\x44',   // nop 0(%rax,%rax,1)
4043                          '\x00', '\x00' };
4044   const char nop6[6] = { '\x66', '\x0f', '\x1f',   // nopw 0(%rax,%rax,1)
4045                          '\x44', '\x00', '\x00' };
4046   const char nop7[7] = { '\x0f', '\x1f', '\x80',   // nopl 0L(%rax)
4047                          '\x00', '\x00', '\x00',
4048                          '\x00' };
4049   const char nop8[8] = { '\x0f', '\x1f', '\x84',   // nopl 0L(%rax,%rax,1)
4050                          '\x00', '\x00', '\x00',
4051                          '\x00', '\x00' };
4052   const char nop9[9] = { '\x66', '\x0f', '\x1f',   // nopw 0L(%rax,%rax,1)
4053                          '\x84', '\x00', '\x00',
4054                          '\x00', '\x00', '\x00' };
4055   const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
4056                            '\x1f', '\x84', '\x00',
4057                            '\x00', '\x00', '\x00',
4058                            '\x00' };
4059   const char nop11[11] = { '\x66', '\x66', '\x2e', // data16
4060                            '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
4061                            '\x00', '\x00', '\x00',
4062                            '\x00', '\x00' };
4063   const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16
4064                            '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
4065                            '\x84', '\x00', '\x00',
4066                            '\x00', '\x00', '\x00' };
4067   const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16
4068                            '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1)
4069                            '\x1f', '\x84', '\x00',
4070                            '\x00', '\x00', '\x00',
4071                            '\x00' };
4072   const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16
4073                            '\x66', '\x66', '\x2e', // data16
4074                            '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1)
4075                            '\x00', '\x00', '\x00',
4076                            '\x00', '\x00' };
4077   const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16
4078                            '\x66', '\x66', '\x66', // data16; data16
4079                            '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1)
4080                            '\x84', '\x00', '\x00',
4081                            '\x00', '\x00', '\x00' };
4082
4083   const char* nops[16] = {
4084     NULL,
4085     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
4086     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
4087   };
4088
4089   return std::string(nops[length], length);
4090 }
4091
4092 // Return the addend to use for a target specific relocation.  The
4093 // only target specific relocation is R_X86_64_TLSDESC for a local
4094 // symbol.  We want to set the addend is the offset of the local
4095 // symbol in the TLS segment.
4096
4097 template<int size>
4098 uint64_t
4099 Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type,
4100                                      uint64_t) const
4101 {
4102   gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
4103   uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
4104   gold_assert(intarg < this->tlsdesc_reloc_info_.size());
4105   const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
4106   const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym);
4107   gold_assert(psymval->is_tls_symbol());
4108   // The value of a TLS symbol is the offset in the TLS segment.
4109   return psymval->value(ti.object, 0);
4110 }
4111
4112 // Return the value to use for the base of a DW_EH_PE_datarel offset
4113 // in an FDE.  Solaris and SVR4 use DW_EH_PE_datarel because their
4114 // assembler can not write out the difference between two labels in
4115 // different sections, so instead of using a pc-relative value they
4116 // use an offset from the GOT.
4117
4118 template<int size>
4119 uint64_t
4120 Target_x86_64<size>::do_ehframe_datarel_base() const
4121 {
4122   gold_assert(this->global_offset_table_ != NULL);
4123   Symbol* sym = this->global_offset_table_;
4124   Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym);
4125   return ssym->value();
4126 }
4127
4128 // FNOFFSET in section SHNDX in OBJECT is the start of a function
4129 // compiled with -fsplit-stack.  The function calls non-split-stack
4130 // code.  We have to change the function so that it always ensures
4131 // that it has enough stack space to run some random function.
4132
4133 template<int size>
4134 void
4135 Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx,
4136                                         section_offset_type fnoffset,
4137                                         section_size_type fnsize,
4138                                         unsigned char* view,
4139                                         section_size_type view_size,
4140                                         std::string* from,
4141                                         std::string* to) const
4142 {
4143   // The function starts with a comparison of the stack pointer and a
4144   // field in the TCB.  This is followed by a jump.
4145
4146   // cmp %fs:NN,%rsp
4147   if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
4148       && fnsize > 9)
4149     {
4150       // We will call __morestack if the carry flag is set after this
4151       // comparison.  We turn the comparison into an stc instruction
4152       // and some nops.
4153       view[fnoffset] = '\xf9';
4154       this->set_view_to_nop(view, view_size, fnoffset + 1, 8);
4155     }
4156   // lea NN(%rsp),%r10
4157   // lea NN(%rsp),%r11
4158   else if ((this->match_view(view, view_size, fnoffset,
4159                              "\x4c\x8d\x94\x24", 4)
4160             || this->match_view(view, view_size, fnoffset,
4161                                 "\x4c\x8d\x9c\x24", 4))
4162            && fnsize > 8)
4163     {
4164       // This is loading an offset from the stack pointer for a
4165       // comparison.  The offset is negative, so we decrease the
4166       // offset by the amount of space we need for the stack.  This
4167       // means we will avoid calling __morestack if there happens to
4168       // be plenty of space on the stack already.
4169       unsigned char* pval = view + fnoffset + 4;
4170       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
4171       val -= parameters->options().split_stack_adjust_size();
4172       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
4173     }
4174   else
4175     {
4176       if (!object->has_no_split_stack())
4177         object->error(_("failed to match split-stack sequence at "
4178                         "section %u offset %0zx"),
4179                       shndx, static_cast<size_t>(fnoffset));
4180       return;
4181     }
4182
4183   // We have to change the function so that it calls
4184   // __morestack_non_split instead of __morestack.  The former will
4185   // allocate additional stack space.
4186   *from = "__morestack";
4187   *to = "__morestack_non_split";
4188 }
4189
4190 // The selector for x86_64 object files.
4191
4192 template<int size>
4193 class Target_selector_x86_64 : public Target_selector_freebsd
4194 {
4195 public:
4196   Target_selector_x86_64()
4197     : Target_selector_freebsd(elfcpp::EM_X86_64, size, false,
4198                               (size == 64
4199                                ? "elf64-x86-64" : "elf32-x86-64"),
4200                               (size == 64
4201                                ? "elf64-x86-64-freebsd"
4202                                : "elf32-x86-64-freebsd"),
4203                               (size == 64 ? "elf_x86_64" : "elf32_x86_64"))
4204   { }
4205
4206   Target*
4207   do_instantiate_target()
4208   { return new Target_x86_64<size>(); }
4209
4210 };
4211
4212 Target_selector_x86_64<64> target_selector_x86_64;
4213 Target_selector_x86_64<32> target_selector_x32;
4214
4215 } // End anonymous namespace.