gold/x86_64.cc

   1 // x86_64.cc -- x86_64 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "parameters.h"
  29 #include "reloc.h"
  30 #include "x86_64.h"
  31 #include "object.h"
  32 #include "symtab.h"
  33 #include "layout.h"
  34 #include "output.h"
  35 #include "target.h"
  36 #include "target-reloc.h"
  37 #include "target-select.h"
  38 #include "tls.h"
  39
  40 namespace
  41 {
  42
  43 using namespace gold;
  44
  45 class Output_data_plt_x86_64;
  46
  47 // The x86_64 target class.
  48 // See the ABI at
  49 //   http://www.x86-64.org/documentation/abi.pdf
  50 // TLS info comes from
  51 //   http://people.redhat.com/drepper/tls.pdf
  52 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  53
  54 class Target_x86_64 : public Sized_target<64, false>
  55 {
  56  public:
  57   // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
  58   // uses only Elf64_Rela relocation entries with explicit addends."
  59   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
  60
  61   Target_x86_64()
  62     : Sized_target<64, false>(&x86_64_info),
  63       got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
  64       copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
  65   { }
  66
  67   // Scan the relocations to look for symbol adjustments.
  68   void
  69   scan_relocs(const General_options& options,
  70               Symbol_table* symtab,
  71               Layout* layout,
  72               Sized_relobj<64, false>* object,
  73               unsigned int data_shndx,
  74               unsigned int sh_type,
  75               const unsigned char* prelocs,
  76               size_t reloc_count,
  77               Output_section* output_section,
  78               bool needs_special_offset_handling,
  79               size_t local_symbol_count,
  80               const unsigned char* plocal_symbols);
  81
  82   // Finalize the sections.
  83   void
  84   do_finalize_sections(Layout*);
  85
  86   // Return the value to use for a dynamic which requires special
  87   // treatment.
  88   uint64_t
  89   do_dynsym_value(const Symbol*) const;
  90
  91   // Relocate a section.
  92   void
  93   relocate_section(const Relocate_info<64, false>*,
  94                    unsigned int sh_type,
  95                    const unsigned char* prelocs,
  96                    size_t reloc_count,
  97                    Output_section* output_section,
  98                    bool needs_special_offset_handling,
  99                    unsigned char* view,
 100                    elfcpp::Elf_types<64>::Elf_Addr view_address,
 101                    section_size_type view_size);
 102
 103   // Scan the relocs during a relocatable link.
 104   void
 105   scan_relocatable_relocs(const General_options& options,
 106                           Symbol_table* symtab,
 107                           Layout* layout,
 108                           Sized_relobj<64, false>* object,
 109                           unsigned int data_shndx,
 110                           unsigned int sh_type,
 111                           const unsigned char* prelocs,
 112                           size_t reloc_count,
 113                           Output_section* output_section,
 114                           bool needs_special_offset_handling,
 115                           size_t local_symbol_count,
 116                           const unsigned char* plocal_symbols,
 117                           Relocatable_relocs*);
 118
 119   // Relocate a section during a relocatable link.
 120   void
 121   relocate_for_relocatable(const Relocate_info<64, false>*,
 122                            unsigned int sh_type,
 123                            const unsigned char* prelocs,
 124                            size_t reloc_count,
 125                            Output_section* output_section,
 126                            off_t offset_in_output_section,
 127                            const Relocatable_relocs*,
 128                            unsigned char* view,
 129                            elfcpp::Elf_types<64>::Elf_Addr view_address,
 130                            section_size_type view_size,
 131                            unsigned char* reloc_view,
 132                            section_size_type reloc_view_size);
 133
 134   // Return a string used to fill a code section with nops.
 135   std::string
 136   do_code_fill(section_size_type length) const;
 137
 138   // Return whether SYM is defined by the ABI.
 139   bool
 140   do_is_defined_by_abi(Symbol* sym) const
 141   { return strcmp(sym->name(), "__tls_get_addr") == 0; }
 142
 143   // Return the size of the GOT section.
 144   section_size_type
 145   got_size()
 146   {
 147     gold_assert(this->got_ != NULL);
 148     return this->got_->data_size();
 149   }
 150
 151  private:
 152   // The class which scans relocations.
 153   class Scan
 154   {
 155   public:
 156     Scan()
 157       : issued_non_pic_error_(false)
 158     { }
 159
 160     inline void
 161     local(const General_options& options, Symbol_table* symtab,
 162           Layout* layout, Target_x86_64* target,
 163           Sized_relobj<64, false>* object,
 164           unsigned int data_shndx,
 165           Output_section* output_section,
 166           const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 167           const elfcpp::Sym<64, false>& lsym);
 168
 169     inline void
 170     global(const General_options& options, Symbol_table* symtab,
 171            Layout* layout, Target_x86_64* target,
 172            Sized_relobj<64, false>* object,
 173            unsigned int data_shndx,
 174            Output_section* output_section,
 175            const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
 176            Symbol* gsym);
 177
 178   private:
 179     static void
 180     unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type);
 181
 182     static void
 183     unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type,
 184                              Symbol*);
 185
 186     void
 187     check_non_pic(Relobj*, unsigned int r_type);
 188
 189     // Whether we have issued an error about a non-PIC compilation.
 190     bool issued_non_pic_error_;
 191   };
 192
 193   // The class which implements relocation.
 194   class Relocate
 195   {
 196    public:
 197     Relocate()
 198       : skip_call_tls_get_addr_(false)
 199     { }
 200
 201     ~Relocate()
 202     {
 203       if (this->skip_call_tls_get_addr_)
 204         {
 205           // FIXME: This needs to specify the location somehow.
 206           gold_error(_("missing expected TLS relocation"));
 207         }
 208     }
 209
 210     // Do a relocation.  Return false if the caller should not issue
 211     // any warnings about this relocation.
 212     inline bool
 213     relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum,
 214              const elfcpp::Rela<64, false>&,
 215              unsigned int r_type, const Sized_symbol<64>*,
 216              const Symbol_value<64>*,
 217              unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 218              section_size_type);
 219
 220    private:
 221     // Do a TLS relocation.
 222     inline void
 223     relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
 224                  size_t relnum, const elfcpp::Rela<64, false>&,
 225                  unsigned int r_type, const Sized_symbol<64>*,
 226                  const Symbol_value<64>*,
 227                  unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
 228                  section_size_type);
 229
 230     // Do a TLS General-Dynamic to Local-Exec transition.
 231     inline void
 232     tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
 233                  Output_segment* tls_segment,
 234                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 235                  elfcpp::Elf_types<64>::Elf_Addr value,
 236                  unsigned char* view,
 237                  section_size_type view_size);
 238
 239     // Do a TLS General-Dynamic to Local-Exec transition.
 240     inline void
 241     tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
 242                  Output_segment* tls_segment,
 243                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 244                  elfcpp::Elf_types<64>::Elf_Addr value,
 245                  unsigned char* view,
 246                  section_size_type view_size);
 247
 248     // Do a TLS Local-Dynamic to Local-Exec transition.
 249     inline void
 250     tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum,
 251                  Output_segment* tls_segment,
 252                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 253                  elfcpp::Elf_types<64>::Elf_Addr value,
 254                  unsigned char* view,
 255                  section_size_type view_size);
 256
 257     // Do a TLS Initial-Exec to Local-Exec transition.
 258     static inline void
 259     tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum,
 260                  Output_segment* tls_segment,
 261                  const elfcpp::Rela<64, false>&, unsigned int r_type,
 262                  elfcpp::Elf_types<64>::Elf_Addr value,
 263                  unsigned char* view,
 264                  section_size_type view_size);
 265
 266     // This is set if we should skip the next reloc, which should be a
 267     // PLT32 reloc against ___tls_get_addr.
 268     bool skip_call_tls_get_addr_;
 269   };
 270
 271   // A class which returns the size required for a relocation type,
 272   // used while scanning relocs during a relocatable link.
 273   class Relocatable_size_for_reloc
 274   {
 275    public:
 276     unsigned int
 277     get_size_for_reloc(unsigned int, Relobj*);
 278   };
 279
 280   // Adjust TLS relocation type based on the options and whether this
 281   // is a local symbol.
 282   static tls::Tls_optimization
 283   optimize_tls_reloc(bool is_final, int r_type);
 284
 285   // Get the GOT section, creating it if necessary.
 286   Output_data_got<64, false>*
 287   got_section(Symbol_table*, Layout*);
 288
 289   // Get the GOT PLT section.
 290   Output_data_space*
 291   got_plt_section() const
 292   {
 293     gold_assert(this->got_plt_ != NULL);
 294     return this->got_plt_;
 295   }
 296
 297   // Create a PLT entry for a global symbol.
 298   void
 299   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 300
 301   // Create a GOT entry for the TLS module index.
 302   unsigned int
 303   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 304                       Sized_relobj<64, false>* object);
 305
 306   // Get the PLT section.
 307   Output_data_plt_x86_64*
 308   plt_section() const
 309   {
 310     gold_assert(this->plt_ != NULL);
 311     return this->plt_;
 312   }
 313
 314   // Get the dynamic reloc section, creating it if necessary.
 315   Reloc_section*
 316   rela_dyn_section(Layout*);
 317
 318   // Return true if the symbol may need a COPY relocation.
 319   // References from an executable object to non-function symbols
 320   // defined in a dynamic object may need a COPY relocation.
 321   bool
 322   may_need_copy_reloc(Symbol* gsym)
 323   {
 324     return (!parameters->options().shared()
 325             && gsym->is_from_dynobj()
 326             && gsym->type() != elfcpp::STT_FUNC);
 327   }
 328
 329   // Copy a relocation against a global symbol.
 330   void
 331   copy_reloc(const General_options*, Symbol_table*, Layout*,
 332              Sized_relobj<64, false>*, unsigned int,
 333              Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
 334
 335   // Information about this specific target which we pass to the
 336   // general Target structure.
 337   static const Target::Target_info x86_64_info;
 338
 339   enum Got_type
 340   {
 341     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 342     GOT_TYPE_TLS_OFFSET = 1,    // GOT entry for TLS offset
 343     GOT_TYPE_TLS_PAIR = 2,      // GOT entry for TLS module/offset pair
 344     GOT_TYPE_TLS_DESC = 3       // GOT entry for TLS_DESC pair
 345   };
 346
 347   // The GOT section.
 348   Output_data_got<64, false>* got_;
 349   // The PLT section.
 350   Output_data_plt_x86_64* plt_;
 351   // The GOT PLT section.
 352   Output_data_space* got_plt_;
 353   // The dynamic reloc section.
 354   Reloc_section* rela_dyn_;
 355   // Relocs saved to avoid a COPY reloc.
 356   Copy_relocs<64, false>* copy_relocs_;
 357   // Space for variables copied with a COPY reloc.
 358   Output_data_space* dynbss_;
 359   // Offset of the GOT entry for the TLS module index;
 360   unsigned int got_mod_index_offset_;
 361 };
 362
 363 const Target::Target_info Target_x86_64::x86_64_info =
 364 {
 365   64,                   // size
 366   false,                // is_big_endian
 367   elfcpp::EM_X86_64,    // machine_code
 368   false,                // has_make_symbol
 369   false,                // has_resolve
 370   true,                 // has_code_fill
 371   true,                 // is_default_stack_executable
 372   '\0',                 // wrap_char
 373   "/lib/ld64.so.1",     // program interpreter
 374   0x400000,             // default_text_segment_address
 375   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 376   0x1000                // common_pagesize (overridable by -z common-page-size)
 377 };
 378
 379 // Get the GOT section, creating it if necessary.
 380
 381 Output_data_got<64, false>*
 382 Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
 383 {
 384   if (this->got_ == NULL)
 385     {
 386       gold_assert(symtab != NULL && layout != NULL);
 387
 388       this->got_ = new Output_data_got<64, false>();
 389
 390       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 391                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 392                                       this->got_);
 393
 394       // The old GNU linker creates a .got.plt section.  We just
 395       // create another set of data in the .got section.  Note that we
 396       // always create a PLT if we create a GOT, although the PLT
 397       // might be empty.
 398       this->got_plt_ = new Output_data_space(8);
 399       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 400                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 401                                       this->got_plt_);
 402
 403       // The first three entries are reserved.
 404       this->got_plt_->set_current_data_size(3 * 8);
 405
 406       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 407       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 408                                     this->got_plt_,
 409                                     0, 0, elfcpp::STT_OBJECT,
 410                                     elfcpp::STB_LOCAL,
 411                                     elfcpp::STV_HIDDEN, 0,
 412                                     false, false);
 413     }
 414
 415   return this->got_;
 416 }
 417
 418 // Get the dynamic reloc section, creating it if necessary.
 419
 420 Target_x86_64::Reloc_section*
 421 Target_x86_64::rela_dyn_section(Layout* layout)
 422 {
 423   if (this->rela_dyn_ == NULL)
 424     {
 425       gold_assert(layout != NULL);
 426       this->rela_dyn_ = new Reloc_section();
 427       layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
 428                                       elfcpp::SHF_ALLOC, this->rela_dyn_);
 429     }
 430   return this->rela_dyn_;
 431 }
 432
 433 // A class to handle the PLT data.
 434
 435 class Output_data_plt_x86_64 : public Output_section_data
 436 {
 437  public:
 438   typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
 439
 440   Output_data_plt_x86_64(Layout*, Output_data_space*);
 441
 442   // Add an entry to the PLT.
 443   void
 444   add_entry(Symbol* gsym);
 445
 446   // Return the .rel.plt section data.
 447   const Reloc_section*
 448   rel_plt() const
 449   { return this->rel_; }
 450
 451  protected:
 452   void
 453   do_adjust_output_section(Output_section* os);
 454
 455  private:
 456   // The size of an entry in the PLT.
 457   static const int plt_entry_size = 16;
 458
 459   // The first entry in the PLT.
 460   // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
 461   // procedure linkage table for both programs and shared objects."
 462   static unsigned char first_plt_entry[plt_entry_size];
 463
 464   // Other entries in the PLT for an executable.
 465   static unsigned char plt_entry[plt_entry_size];
 466
 467   // Set the final size.
 468   void
 469   set_final_data_size()
 470   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 471
 472   // Write out the PLT data.
 473   void
 474   do_write(Output_file*);
 475
 476   // The reloc section.
 477   Reloc_section* rel_;
 478   // The .got.plt section.
 479   Output_data_space* got_plt_;
 480   // The number of PLT entries.
 481   unsigned int count_;
 482 };
 483
 484 // Create the PLT section.  The ordinary .got section is an argument,
 485 // since we need to refer to the start.  We also create our own .got
 486 // section just for PLT entries.
 487
 488 Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout,
 489                                                Output_data_space* got_plt)
 490   : Output_section_data(8), got_plt_(got_plt), count_(0)
 491 {
 492   this->rel_ = new Reloc_section();
 493   layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
 494                                   elfcpp::SHF_ALLOC, this->rel_);
 495 }
 496
 497 void
 498 Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
 499 {
 500   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 501   // linker, and so do we.
 502   os->set_entsize(4);
 503 }
 504
 505 // Add an entry to the PLT.
 506
 507 void
 508 Output_data_plt_x86_64::add_entry(Symbol* gsym)
 509 {
 510   gold_assert(!gsym->has_plt_offset());
 511
 512   // Note that when setting the PLT offset we skip the initial
 513   // reserved PLT entry.
 514   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 515
 516   ++this->count_;
 517
 518   section_offset_type got_offset = this->got_plt_->current_data_size();
 519
 520   // Every PLT entry needs a GOT entry which points back to the PLT
 521   // entry (this will be changed by the dynamic linker, normally
 522   // lazily when the function is called).
 523   this->got_plt_->set_current_data_size(got_offset + 8);
 524
 525   // Every PLT entry needs a reloc.
 526   gsym->set_needs_dynsym_entry();
 527   this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
 528                          got_offset, 0);
 529
 530   // Note that we don't need to save the symbol.  The contents of the
 531   // PLT are independent of which symbols are used.  The symbols only
 532   // appear in the relocations.
 533 }
 534
 535 // The first entry in the PLT for an executable.
 536
 537 unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
 538 {
 539   // From AMD64 ABI Draft 0.98, page 76
 540   0xff, 0x35,   // pushq contents of memory address
 541   0, 0, 0, 0,   // replaced with address of .got + 8
 542   0xff, 0x25,   // jmp indirect
 543   0, 0, 0, 0,   // replaced with address of .got + 16
 544   0x90, 0x90, 0x90, 0x90   // noop (x4)
 545 };
 546
 547 // Subsequent entries in the PLT for an executable.
 548
 549 unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
 550 {
 551   // From AMD64 ABI Draft 0.98, page 76
 552   0xff, 0x25,   // jmpq indirect
 553   0, 0, 0, 0,   // replaced with address of symbol in .got
 554   0x68,         // pushq immediate
 555   0, 0, 0, 0,   // replaced with offset into relocation table
 556   0xe9,         // jmpq relative
 557   0, 0, 0, 0    // replaced with offset to start of .plt
 558 };
 559
 560 // Write out the PLT.  This uses the hand-coded instructions above,
 561 // and adjusts them as needed.  This is specified by the AMD64 ABI.
 562
 563 void
 564 Output_data_plt_x86_64::do_write(Output_file* of)
 565 {
 566   const off_t offset = this->offset();
 567   const section_size_type oview_size =
 568     convert_to_section_size_type(this->data_size());
 569   unsigned char* const oview = of->get_output_view(offset, oview_size);
 570
 571   const off_t got_file_offset = this->got_plt_->offset();
 572   const section_size_type got_size =
 573     convert_to_section_size_type(this->got_plt_->data_size());
 574   unsigned char* const got_view = of->get_output_view(got_file_offset,
 575                                                       got_size);
 576
 577   unsigned char* pov = oview;
 578
 579   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 580   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 581
 582   memcpy(pov, first_plt_entry, plt_entry_size);
 583   // We do a jmp relative to the PC at the end of this instruction.
 584   elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
 585                                               - (plt_address + 6));
 586   elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
 587                                     - (plt_address + 12));
 588   pov += plt_entry_size;
 589
 590   unsigned char* got_pov = got_view;
 591
 592   memset(got_pov, 0, 24);
 593   got_pov += 24;
 594
 595   unsigned int plt_offset = plt_entry_size;
 596   unsigned int got_offset = 24;
 597   const unsigned int count = this->count_;
 598   for (unsigned int plt_index = 0;
 599        plt_index < count;
 600        ++plt_index,
 601          pov += plt_entry_size,
 602          got_pov += 8,
 603          plt_offset += plt_entry_size,
 604          got_offset += 8)
 605     {
 606       // Set and adjust the PLT entry itself.
 607       memcpy(pov, plt_entry, plt_entry_size);
 608       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 609                                                   (got_address + got_offset
 610                                                    - (plt_address + plt_offset
 611                                                       + 6)));
 612
 613       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
 614       elfcpp::Swap<32, false>::writeval(pov + 12,
 615                                         - (plt_offset + plt_entry_size));
 616
 617       // Set the entry in the GOT.
 618       elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
 619     }
 620
 621   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 622   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 623
 624   of->write_output_view(offset, oview_size, oview);
 625   of->write_output_view(got_file_offset, got_size, got_view);
 626 }
 627
 628 // Create a PLT entry for a global symbol.
 629
 630 void
 631 Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout,
 632                               Symbol* gsym)
 633 {
 634   if (gsym->has_plt_offset())
 635     return;
 636
 637   if (this->plt_ == NULL)
 638     {
 639       // Create the GOT sections first.
 640       this->got_section(symtab, layout);
 641
 642       this->plt_ = new Output_data_plt_x86_64(layout, this->got_plt_);
 643       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 644                                       (elfcpp::SHF_ALLOC
 645                                        | elfcpp::SHF_EXECINSTR),
 646                                       this->plt_);
 647     }
 648
 649   this->plt_->add_entry(gsym);
 650 }
 651
 652 // Create a GOT entry for the TLS module index.
 653
 654 unsigned int
 655 Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 656                                    Sized_relobj<64, false>* object)
 657 {
 658   if (this->got_mod_index_offset_ == -1U)
 659     {
 660       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 661       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 662       Output_data_got<64, false>* got = this->got_section(symtab, layout);
 663       unsigned int got_offset = got->add_constant(0);
 664       rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
 665                           got_offset, 0);
 666       got->add_constant(0);
 667       this->got_mod_index_offset_ = got_offset;
 668     }
 669   return this->got_mod_index_offset_;
 670 }
 671
 672 // Handle a relocation against a non-function symbol defined in a
 673 // dynamic object.  The traditional way to handle this is to generate
 674 // a COPY relocation to copy the variable at runtime from the shared
 675 // object into the executable's data segment.  However, this is
 676 // undesirable in general, as if the size of the object changes in the
 677 // dynamic object, the executable will no longer work correctly.  If
 678 // this relocation is in a writable section, then we can create a
 679 // dynamic reloc and the dynamic linker will resolve it to the correct
 680 // address at runtime.  However, we do not want do that if the
 681 // relocation is in a read-only section, as it would prevent the
 682 // readonly segment from being shared.  And if we have to eventually
 683 // generate a COPY reloc, then any dynamic relocations will be
 684 // useless.  So this means that if this is a writable section, we need
 685 // to save the relocation until we see whether we have to create a
 686 // COPY relocation for this symbol for any other relocation.
 687
 688 void
 689 Target_x86_64::copy_reloc(const General_options* options,
 690                           Symbol_table* symtab,
 691                           Layout* layout,
 692                           Sized_relobj<64, false>* object,
 693                           unsigned int data_shndx,
 694                           Output_section* output_section,
 695                           Symbol* gsym,
 696                           const elfcpp::Rela<64, false>& rela)
 697 {
 698   Sized_symbol<64>* ssym = symtab->get_sized_symbol<64>(gsym);
 699
 700   if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
 701                                                data_shndx, ssym))
 702     {
 703       // So far we do not need a COPY reloc.  Save this relocation.
 704       // If it turns out that we never need a COPY reloc for this
 705       // symbol, then we will emit the relocation.
 706       if (this->copy_relocs_ == NULL)
 707         this->copy_relocs_ = new Copy_relocs<64, false>();
 708       this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
 709     }
 710   else
 711     {
 712       // Allocate space for this symbol in the .bss section.
 713
 714       elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
 715
 716       // There is no defined way to determine the required alignment
 717       // of the symbol.  We pick the alignment based on the size.  We
 718       // set an arbitrary maximum of 256.
 719       unsigned int align;
 720       for (align = 1; align < 512; align <<= 1)
 721         if ((symsize & align) != 0)
 722           break;
 723
 724       if (this->dynbss_ == NULL)
 725         {
 726           this->dynbss_ = new Output_data_space(align);
 727           layout->add_output_section_data(".bss",
 728                                           elfcpp::SHT_NOBITS,
 729                                           (elfcpp::SHF_ALLOC
 730                                            | elfcpp::SHF_WRITE),
 731                                           this->dynbss_);
 732         }
 733
 734       Output_data_space* dynbss = this->dynbss_;
 735
 736       if (align > dynbss->addralign())
 737         dynbss->set_space_alignment(align);
 738
 739       section_size_type dynbss_size = dynbss->current_data_size();
 740       dynbss_size = align_address(dynbss_size, align);
 741       section_size_type offset = dynbss_size;
 742       dynbss->set_current_data_size(dynbss_size + symsize);
 743
 744       symtab->define_with_copy_reloc(ssym, dynbss, offset);
 745
 746       // Add the COPY reloc.
 747       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
 748       rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
 749     }
 750 }
 751
 752
 753 // Optimize the TLS relocation type based on what we know about the
 754 // symbol.  IS_FINAL is true if the final address of this symbol is
 755 // known at link time.
 756
 757 tls::Tls_optimization
 758 Target_x86_64::optimize_tls_reloc(bool is_final, int r_type)
 759 {
 760   // If we are generating a shared library, then we can't do anything
 761   // in the linker.
 762   if (parameters->options().shared())
 763     return tls::TLSOPT_NONE;
 764
 765   switch (r_type)
 766     {
 767     case elfcpp::R_X86_64_TLSGD:
 768     case elfcpp::R_X86_64_GOTPC32_TLSDESC:
 769     case elfcpp::R_X86_64_TLSDESC_CALL:
 770       // These are General-Dynamic which permits fully general TLS
 771       // access.  Since we know that we are generating an executable,
 772       // we can convert this to Initial-Exec.  If we also know that
 773       // this is a local symbol, we can further switch to Local-Exec.
 774       if (is_final)
 775         return tls::TLSOPT_TO_LE;
 776       return tls::TLSOPT_TO_IE;
 777
 778     case elfcpp::R_X86_64_TLSLD:
 779       // This is Local-Dynamic, which refers to a local symbol in the
 780       // dynamic TLS block.  Since we know that we generating an
 781       // executable, we can switch to Local-Exec.
 782       return tls::TLSOPT_TO_LE;
 783
 784     case elfcpp::R_X86_64_DTPOFF32:
 785     case elfcpp::R_X86_64_DTPOFF64:
 786       // Another Local-Dynamic reloc.
 787       return tls::TLSOPT_TO_LE;
 788
 789     case elfcpp::R_X86_64_GOTTPOFF:
 790       // These are Initial-Exec relocs which get the thread offset
 791       // from the GOT.  If we know that we are linking against the
 792       // local symbol, we can switch to Local-Exec, which links the
 793       // thread offset into the instruction.
 794       if (is_final)
 795         return tls::TLSOPT_TO_LE;
 796       return tls::TLSOPT_NONE;
 797
 798     case elfcpp::R_X86_64_TPOFF32:
 799       // When we already have Local-Exec, there is nothing further we
 800       // can do.
 801       return tls::TLSOPT_NONE;
 802
 803     default:
 804       gold_unreachable();
 805     }
 806 }
 807
 808 // Report an unsupported relocation against a local symbol.
 809
 810 void
 811 Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object,
 812                                              unsigned int r_type)
 813 {
 814   gold_error(_("%s: unsupported reloc %u against local symbol"),
 815              object->name().c_str(), r_type);
 816 }
 817
 818 // We are about to emit a dynamic relocation of type R_TYPE.  If the
 819 // dynamic linker does not support it, issue an error.  The GNU linker
 820 // only issues a non-PIC error for an allocated read-only section.
 821 // Here we know the section is allocated, but we don't know that it is
 822 // read-only.  But we check for all the relocation types which the
 823 // glibc dynamic linker supports, so it seems appropriate to issue an
 824 // error even if the section is not read-only.
 825
 826 void
 827 Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
 828 {
 829   switch (r_type)
 830     {
 831       // These are the relocation types supported by glibc for x86_64.
 832     case elfcpp::R_X86_64_RELATIVE:
 833     case elfcpp::R_X86_64_GLOB_DAT:
 834     case elfcpp::R_X86_64_JUMP_SLOT:
 835     case elfcpp::R_X86_64_DTPMOD64:
 836     case elfcpp::R_X86_64_DTPOFF64:
 837     case elfcpp::R_X86_64_TPOFF64:
 838     case elfcpp::R_X86_64_64:
 839     case elfcpp::R_X86_64_32:
 840     case elfcpp::R_X86_64_PC32:
 841     case elfcpp::R_X86_64_COPY:
 842       return;
 843
 844     default:
 845       // This prevents us from issuing more than one error per reloc
 846       // section.  But we can still wind up issuing more than one
 847       // error per object file.
 848       if (this->issued_non_pic_error_)
 849         return;
 850       object->error(_("requires unsupported dynamic reloc; "
 851                       "recompile with -fPIC"));
 852       this->issued_non_pic_error_ = true;
 853       return;
 854
 855     case elfcpp::R_X86_64_NONE:
 856       gold_unreachable();
 857     }
 858 }
 859
 860 // Scan a relocation for a local symbol.
 861
 862 inline void
 863 Target_x86_64::Scan::local(const General_options&,
 864                            Symbol_table* symtab,
 865                            Layout* layout,
 866                            Target_x86_64* target,
 867                            Sized_relobj<64, false>* object,
 868                            unsigned int data_shndx,
 869                            Output_section* output_section,
 870                            const elfcpp::Rela<64, false>& reloc,
 871                            unsigned int r_type,
 872                            const elfcpp::Sym<64, false>& lsym)
 873 {
 874   switch (r_type)
 875     {
 876     case elfcpp::R_X86_64_NONE:
 877     case elfcpp::R_386_GNU_VTINHERIT:
 878     case elfcpp::R_386_GNU_VTENTRY:
 879       break;
 880
 881     case elfcpp::R_X86_64_64:
 882       // If building a shared library (or a position-independent
 883       // executable), we need to create a dynamic relocation for this
 884       // location.  The relocation applied at link time will apply the
 885       // link-time value, so we flag the location with an
 886       // R_X86_64_RELATIVE relocation so the dynamic loader can
 887       // relocate it easily.
 888       if (parameters->options().output_is_position_independent())
 889         {
 890           unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 891           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 892           rela_dyn->add_local_relative(object, r_sym,
 893                                        elfcpp::R_X86_64_RELATIVE,
 894                                        output_section, data_shndx,
 895                                        reloc.get_r_offset(),
 896                                        reloc.get_r_addend());
 897         }
 898       break;
 899
 900     case elfcpp::R_X86_64_32:
 901     case elfcpp::R_X86_64_32S:
 902     case elfcpp::R_X86_64_16:
 903     case elfcpp::R_X86_64_8:
 904       // If building a shared library (or a position-independent
 905       // executable), we need to create a dynamic relocation for this
 906       // location.  We can't use an R_X86_64_RELATIVE relocation
 907       // because that is always a 64-bit relocation.
 908       if (parameters->options().output_is_position_independent())
 909         {
 910           this->check_non_pic(object, r_type);
 911
 912           Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 913           if (lsym.get_st_type() != elfcpp::STT_SECTION)
 914             {
 915               unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 916               rela_dyn->add_local(object, r_sym, r_type, output_section,
 917                                   data_shndx, reloc.get_r_offset(),
 918                                   reloc.get_r_addend());
 919             }
 920           else
 921             {
 922               gold_assert(lsym.get_st_value() == 0);
 923               rela_dyn->add_local_section(object, lsym.get_st_shndx(),
 924                                           r_type, output_section,
 925                                           data_shndx, reloc.get_r_offset(),
 926                                           reloc.get_r_addend());
 927             }
 928         }
 929       break;
 930
 931     case elfcpp::R_X86_64_PC64:
 932     case elfcpp::R_X86_64_PC32:
 933     case elfcpp::R_X86_64_PC16:
 934     case elfcpp::R_X86_64_PC8:
 935       break;
 936
 937     case elfcpp::R_X86_64_PLT32:
 938       // Since we know this is a local symbol, we can handle this as a
 939       // PC32 reloc.
 940       break;
 941
 942     case elfcpp::R_X86_64_GOTPC32:
 943     case elfcpp::R_X86_64_GOTOFF64:
 944     case elfcpp::R_X86_64_GOTPC64:
 945     case elfcpp::R_X86_64_PLTOFF64:
 946       // We need a GOT section.
 947       target->got_section(symtab, layout);
 948       // For PLTOFF64, we'd normally want a PLT section, but since we
 949       // know this is a local symbol, no PLT is needed.
 950       break;
 951
 952     case elfcpp::R_X86_64_GOT64:
 953     case elfcpp::R_X86_64_GOT32:
 954     case elfcpp::R_X86_64_GOTPCREL64:
 955     case elfcpp::R_X86_64_GOTPCREL:
 956     case elfcpp::R_X86_64_GOTPLT64:
 957       {
 958         // The symbol requires a GOT entry.
 959         Output_data_got<64, false>* got = target->got_section(symtab, layout);
 960         unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
 961         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
 962           {
 963             // If we are generating a shared object, we need to add a
 964             // dynamic relocation for this symbol's GOT entry.
 965             if (parameters->options().output_is_position_independent())
 966               {
 967                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
 968                 // R_X86_64_RELATIVE assumes a 64-bit relocation.
 969                 if (r_type != elfcpp::R_X86_64_GOT32)
 970                   rela_dyn->add_local_relative(
 971                       object, r_sym, elfcpp::R_X86_64_RELATIVE, got,
 972                       object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
 973                 else
 974                   {
 975                     this->check_non_pic(object, r_type);
 976
 977                     gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
 978                     rela_dyn->add_local(
 979                         object, r_sym, r_type, got,
 980                         object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
 981                   }
 982               }
 983           }
 984         // For GOTPLT64, we'd normally want a PLT section, but since
 985         // we know this is a local symbol, no PLT is needed.
 986       }
 987       break;
 988
 989     case elfcpp::R_X86_64_COPY:
 990     case elfcpp::R_X86_64_GLOB_DAT:
 991     case elfcpp::R_X86_64_JUMP_SLOT:
 992     case elfcpp::R_X86_64_RELATIVE:
 993       // These are outstanding tls relocs, which are unexpected when linking
 994     case elfcpp::R_X86_64_TPOFF64:
 995     case elfcpp::R_X86_64_DTPMOD64:
 996     case elfcpp::R_X86_64_TLSDESC:
 997       gold_error(_("%s: unexpected reloc %u in object file"),
 998                  object->name().c_str(), r_type);
 999       break;
1000
1001       // These are initial tls relocs, which are expected when linking
1002     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1003     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1004     case elfcpp::R_X86_64_TLSDESC_CALL:
1005     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1006     case elfcpp::R_X86_64_DTPOFF32:
1007     case elfcpp::R_X86_64_DTPOFF64:
1008     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1009     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1010       {
1011         bool output_is_shared = parameters->options().shared();
1012         const tls::Tls_optimization optimized_type
1013             = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
1014         switch (r_type)
1015           {
1016           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1017             if (optimized_type == tls::TLSOPT_NONE)
1018               {
1019                 // Create a pair of GOT entries for the module index and
1020                 // dtv-relative offset.
1021                 Output_data_got<64, false>* got
1022                     = target->got_section(symtab, layout);
1023                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1024                 got->add_local_pair_with_rela(object, r_sym,
1025                                               lsym.get_st_shndx(),
1026                                               GOT_TYPE_TLS_PAIR,
1027                                               target->rela_dyn_section(layout),
1028                                               elfcpp::R_X86_64_DTPMOD64, 0);
1029               }
1030             else if (optimized_type != tls::TLSOPT_TO_LE)
1031               unsupported_reloc_local(object, r_type);
1032             break;
1033
1034           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1035           case elfcpp::R_X86_64_TLSDESC_CALL:
1036             // FIXME: If not relaxing to LE, we need to generate
1037             // a GOT entry with a R_x86_64_TLSDESC reloc.
1038             if (optimized_type != tls::TLSOPT_TO_LE)
1039               unsupported_reloc_local(object, r_type);
1040             break;
1041
1042           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1043             if (optimized_type == tls::TLSOPT_NONE)
1044               {
1045                 // Create a GOT entry for the module index.
1046                 target->got_mod_index_entry(symtab, layout, object);
1047               }
1048             else if (optimized_type != tls::TLSOPT_TO_LE)
1049               unsupported_reloc_local(object, r_type);
1050             break;
1051
1052           case elfcpp::R_X86_64_DTPOFF32:
1053           case elfcpp::R_X86_64_DTPOFF64:
1054             break;
1055
1056           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1057             layout->set_has_static_tls();
1058             if (optimized_type == tls::TLSOPT_NONE)
1059               {
1060                 // Create a GOT entry for the tp-relative offset.
1061                 Output_data_got<64, false>* got
1062                     = target->got_section(symtab, layout);
1063                 unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
1064                 got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
1065                                          target->rela_dyn_section(layout),
1066                                          elfcpp::R_X86_64_TPOFF64);
1067               }
1068             else if (optimized_type != tls::TLSOPT_TO_LE)
1069               unsupported_reloc_local(object, r_type);
1070             break;
1071
1072           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1073             layout->set_has_static_tls();
1074             if (output_is_shared)
1075               unsupported_reloc_local(object, r_type);
1076             break;
1077
1078           default:
1079             gold_unreachable();
1080           }
1081       }
1082       break;
1083
1084     case elfcpp::R_X86_64_SIZE32:
1085     case elfcpp::R_X86_64_SIZE64:
1086     default:
1087       gold_error(_("%s: unsupported reloc %u against local symbol"),
1088                  object->name().c_str(), r_type);
1089       break;
1090     }
1091 }
1092
1093
1094 // Report an unsupported relocation against a global symbol.
1095
1096 void
1097 Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object,
1098                                               unsigned int r_type,
1099                                               Symbol* gsym)
1100 {
1101   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1102              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1103 }
1104
1105 // Scan a relocation for a global symbol.
1106
1107 inline void
1108 Target_x86_64::Scan::global(const General_options& options,
1109                             Symbol_table* symtab,
1110                             Layout* layout,
1111                             Target_x86_64* target,
1112                             Sized_relobj<64, false>* object,
1113                             unsigned int data_shndx,
1114                             Output_section* output_section,
1115                             const elfcpp::Rela<64, false>& reloc,
1116                             unsigned int r_type,
1117                             Symbol* gsym)
1118 {
1119   switch (r_type)
1120     {
1121     case elfcpp::R_X86_64_NONE:
1122     case elfcpp::R_386_GNU_VTINHERIT:
1123     case elfcpp::R_386_GNU_VTENTRY:
1124       break;
1125
1126     case elfcpp::R_X86_64_64:
1127     case elfcpp::R_X86_64_32:
1128     case elfcpp::R_X86_64_32S:
1129     case elfcpp::R_X86_64_16:
1130     case elfcpp::R_X86_64_8:
1131       {
1132         // Make a PLT entry if necessary.
1133         if (gsym->needs_plt_entry())
1134           {
1135             target->make_plt_entry(symtab, layout, gsym);
1136             // Since this is not a PC-relative relocation, we may be
1137             // taking the address of a function. In that case we need to
1138             // set the entry in the dynamic symbol table to the address of
1139             // the PLT entry.
1140             if (gsym->is_from_dynobj() && !parameters->options().shared())
1141               gsym->set_needs_dynsym_value();
1142           }
1143         // Make a dynamic relocation if necessary.
1144         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1145           {
1146             if (target->may_need_copy_reloc(gsym))
1147               {
1148                 target->copy_reloc(&options, symtab, layout, object,
1149                                    data_shndx, output_section, gsym, reloc);
1150               }
1151             else if (r_type == elfcpp::R_X86_64_64
1152                      && gsym->can_use_relative_reloc(false))
1153               {
1154                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1155                 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
1156                                               output_section, object,
1157                                               data_shndx, reloc.get_r_offset(),
1158                                               reloc.get_r_addend());
1159               }
1160             else
1161               {
1162                 this->check_non_pic(object, r_type);
1163                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1164                 rela_dyn->add_global(gsym, r_type, output_section, object,
1165                                      data_shndx, reloc.get_r_offset(),
1166                                      reloc.get_r_addend());
1167               }
1168           }
1169       }
1170       break;
1171
1172     case elfcpp::R_X86_64_PC64:
1173     case elfcpp::R_X86_64_PC32:
1174     case elfcpp::R_X86_64_PC16:
1175     case elfcpp::R_X86_64_PC8:
1176       {
1177         // Make a PLT entry if necessary.
1178         if (gsym->needs_plt_entry())
1179           target->make_plt_entry(symtab, layout, gsym);
1180         // Make a dynamic relocation if necessary.
1181         int flags = Symbol::NON_PIC_REF;
1182         if (gsym->type() == elfcpp::STT_FUNC)
1183           flags |= Symbol::FUNCTION_CALL;
1184         if (gsym->needs_dynamic_reloc(flags))
1185           {
1186             if (target->may_need_copy_reloc(gsym))
1187               {
1188                 target->copy_reloc(&options, symtab, layout, object,
1189                                    data_shndx, output_section, gsym, reloc);
1190               }
1191             else
1192               {
1193                 this->check_non_pic(object, r_type);
1194                 Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1195                 rela_dyn->add_global(gsym, r_type, output_section, object,
1196                                      data_shndx, reloc.get_r_offset(),
1197                                      reloc.get_r_addend());
1198               }
1199           }
1200       }
1201       break;
1202
1203     case elfcpp::R_X86_64_GOT64:
1204     case elfcpp::R_X86_64_GOT32:
1205     case elfcpp::R_X86_64_GOTPCREL64:
1206     case elfcpp::R_X86_64_GOTPCREL:
1207     case elfcpp::R_X86_64_GOTPLT64:
1208       {
1209         // The symbol requires a GOT entry.
1210         Output_data_got<64, false>* got = target->got_section(symtab, layout);
1211         if (gsym->final_value_is_known())
1212           got->add_global(gsym, GOT_TYPE_STANDARD);
1213         else
1214           {
1215             // If this symbol is not fully resolved, we need to add a
1216             // dynamic relocation for it.
1217             Reloc_section* rela_dyn = target->rela_dyn_section(layout);
1218             if (gsym->is_from_dynobj()
1219                 || gsym->is_undefined()
1220                 || gsym->is_preemptible())
1221               got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
1222                                         elfcpp::R_X86_64_GLOB_DAT);
1223             else
1224               {
1225                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1226                   rela_dyn->add_global_relative(
1227                       gsym, elfcpp::R_X86_64_RELATIVE, got,
1228                       gsym->got_offset(GOT_TYPE_STANDARD), 0);
1229               }
1230           }
1231         // For GOTPLT64, we also need a PLT entry (but only if the
1232         // symbol is not fully resolved).
1233         if (r_type == elfcpp::R_X86_64_GOTPLT64
1234             && !gsym->final_value_is_known())
1235           target->make_plt_entry(symtab, layout, gsym);
1236       }
1237       break;
1238
1239     case elfcpp::R_X86_64_PLT32:
1240       // If the symbol is fully resolved, this is just a PC32 reloc.
1241       // Otherwise we need a PLT entry.
1242       if (gsym->final_value_is_known())
1243         break;
1244       // If building a shared library, we can also skip the PLT entry
1245       // if the symbol is defined in the output file and is protected
1246       // or hidden.
1247       if (gsym->is_defined()
1248           && !gsym->is_from_dynobj()
1249           && !gsym->is_preemptible())
1250         break;
1251       target->make_plt_entry(symtab, layout, gsym);
1252       break;
1253
1254     case elfcpp::R_X86_64_GOTPC32:
1255     case elfcpp::R_X86_64_GOTOFF64:
1256     case elfcpp::R_X86_64_GOTPC64:
1257     case elfcpp::R_X86_64_PLTOFF64:
1258       // We need a GOT section.
1259       target->got_section(symtab, layout);
1260       // For PLTOFF64, we also need a PLT entry (but only if the
1261       // symbol is not fully resolved).
1262       if (r_type == elfcpp::R_X86_64_PLTOFF64
1263           && !gsym->final_value_is_known())
1264         target->make_plt_entry(symtab, layout, gsym);
1265       break;
1266
1267     case elfcpp::R_X86_64_COPY:
1268     case elfcpp::R_X86_64_GLOB_DAT:
1269     case elfcpp::R_X86_64_JUMP_SLOT:
1270     case elfcpp::R_X86_64_RELATIVE:
1271       // These are outstanding tls relocs, which are unexpected when linking
1272     case elfcpp::R_X86_64_TPOFF64:
1273     case elfcpp::R_X86_64_DTPMOD64:
1274     case elfcpp::R_X86_64_TLSDESC:
1275       gold_error(_("%s: unexpected reloc %u in object file"),
1276                  object->name().c_str(), r_type);
1277       break;
1278
1279       // These are initial tls relocs, which are expected for global()
1280     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1281     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1282     case elfcpp::R_X86_64_TLSDESC_CALL:
1283     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1284     case elfcpp::R_X86_64_DTPOFF32:
1285     case elfcpp::R_X86_64_DTPOFF64:
1286     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1287     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1288       {
1289         const bool is_final = gsym->final_value_is_known();
1290         const tls::Tls_optimization optimized_type
1291             = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1292         switch (r_type)
1293           {
1294           case elfcpp::R_X86_64_TLSGD:       // General-dynamic
1295             if (optimized_type == tls::TLSOPT_NONE)
1296               {
1297                 // Create a pair of GOT entries for the module index and
1298                 // dtv-relative offset.
1299                 Output_data_got<64, false>* got
1300                     = target->got_section(symtab, layout);
1301                 got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
1302                                                target->rela_dyn_section(layout),
1303                                                elfcpp::R_X86_64_DTPMOD64,
1304                                                elfcpp::R_X86_64_DTPOFF64);
1305               }
1306             else if (optimized_type == tls::TLSOPT_TO_IE)
1307               {
1308                 // Create a GOT entry for the tp-relative offset.
1309                 Output_data_got<64, false>* got
1310                     = target->got_section(symtab, layout);
1311                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1312                                           target->rela_dyn_section(layout),
1313                                           elfcpp::R_X86_64_TPOFF64);
1314               }
1315             else if (optimized_type != tls::TLSOPT_TO_LE)
1316               unsupported_reloc_global(object, r_type, gsym);
1317             break;
1318
1319           case elfcpp::R_X86_64_GOTPC32_TLSDESC:
1320           case elfcpp::R_X86_64_TLSDESC_CALL:
1321             // FIXME: If not relaxing to LE, we need to generate
1322             // DTPMOD64 and DTPOFF64, or TLSDESC, relocs.
1323             if (optimized_type != tls::TLSOPT_TO_LE)
1324               unsupported_reloc_global(object, r_type, gsym);
1325             break;
1326
1327           case elfcpp::R_X86_64_TLSLD:       // Local-dynamic
1328             if (optimized_type == tls::TLSOPT_NONE)
1329               {
1330                 // Create a GOT entry for the module index.
1331                 target->got_mod_index_entry(symtab, layout, object);
1332               }
1333             else if (optimized_type != tls::TLSOPT_TO_LE)
1334               unsupported_reloc_global(object, r_type, gsym);
1335             break;
1336
1337           case elfcpp::R_X86_64_DTPOFF32:
1338           case elfcpp::R_X86_64_DTPOFF64:
1339             break;
1340
1341           case elfcpp::R_X86_64_GOTTPOFF:    // Initial-exec
1342             layout->set_has_static_tls();
1343             if (optimized_type == tls::TLSOPT_NONE)
1344               {
1345                 // Create a GOT entry for the tp-relative offset.
1346                 Output_data_got<64, false>* got
1347                     = target->got_section(symtab, layout);
1348                 got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
1349                                           target->rela_dyn_section(layout),
1350                                           elfcpp::R_X86_64_TPOFF64);
1351               }
1352             else if (optimized_type != tls::TLSOPT_TO_LE)
1353               unsupported_reloc_global(object, r_type, gsym);
1354             break;
1355
1356           case elfcpp::R_X86_64_TPOFF32:     // Local-exec
1357             layout->set_has_static_tls();
1358             if (parameters->options().shared())
1359               unsupported_reloc_local(object, r_type);
1360             break;
1361
1362           default:
1363             gold_unreachable();
1364           }
1365       }
1366       break;
1367
1368     case elfcpp::R_X86_64_SIZE32:
1369     case elfcpp::R_X86_64_SIZE64:
1370     default:
1371       gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1372                  object->name().c_str(), r_type,
1373                  gsym->demangled_name().c_str());
1374       break;
1375     }
1376 }
1377
1378 // Scan relocations for a section.
1379
1380 void
1381 Target_x86_64::scan_relocs(const General_options& options,
1382                            Symbol_table* symtab,
1383                            Layout* layout,
1384                            Sized_relobj<64, false>* object,
1385                            unsigned int data_shndx,
1386                            unsigned int sh_type,
1387                            const unsigned char* prelocs,
1388                            size_t reloc_count,
1389                            Output_section* output_section,
1390                            bool needs_special_offset_handling,
1391                            size_t local_symbol_count,
1392                            const unsigned char* plocal_symbols)
1393 {
1394   if (sh_type == elfcpp::SHT_REL)
1395     {
1396       gold_error(_("%s: unsupported REL reloc section"),
1397                  object->name().c_str());
1398       return;
1399     }
1400
1401   gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
1402       Target_x86_64::Scan>(
1403     options,
1404     symtab,
1405     layout,
1406     this,
1407     object,
1408     data_shndx,
1409     prelocs,
1410     reloc_count,
1411     output_section,
1412     needs_special_offset_handling,
1413     local_symbol_count,
1414     plocal_symbols);
1415 }
1416
1417 // Finalize the sections.
1418
1419 void
1420 Target_x86_64::do_finalize_sections(Layout* layout)
1421 {
1422   // Fill in some more dynamic tags.
1423   Output_data_dynamic* const odyn = layout->dynamic_data();
1424   if (odyn != NULL)
1425     {
1426       if (this->got_plt_ != NULL)
1427         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1428
1429       if (this->plt_ != NULL)
1430         {
1431           const Output_data* od = this->plt_->rel_plt();
1432           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1433           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1434           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA);
1435         }
1436
1437       if (this->rela_dyn_ != NULL)
1438         {
1439           const Output_data* od = this->rela_dyn_;
1440           odyn->add_section_address(elfcpp::DT_RELA, od);
1441           odyn->add_section_size(elfcpp::DT_RELASZ, od);
1442           odyn->add_constant(elfcpp::DT_RELAENT,
1443                              elfcpp::Elf_sizes<64>::rela_size);
1444         }
1445
1446       if (!parameters->options().shared())
1447         {
1448           // The value of the DT_DEBUG tag is filled in by the dynamic
1449           // linker at run time, and used by the debugger.
1450           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1451         }
1452     }
1453
1454   // Emit any relocs we saved in an attempt to avoid generating COPY
1455   // relocs.
1456   if (this->copy_relocs_ == NULL)
1457     return;
1458   if (this->copy_relocs_->any_to_emit())
1459     {
1460       Reloc_section* rela_dyn = this->rela_dyn_section(layout);
1461       this->copy_relocs_->emit(rela_dyn);
1462     }
1463   delete this->copy_relocs_;
1464   this->copy_relocs_ = NULL;
1465 }
1466
1467 // Perform a relocation.
1468
1469 inline bool
1470 Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
1471                                   Target_x86_64* target,
1472                                   size_t relnum,
1473                                   const elfcpp::Rela<64, false>& rela,
1474                                   unsigned int r_type,
1475                                   const Sized_symbol<64>* gsym,
1476                                   const Symbol_value<64>* psymval,
1477                                   unsigned char* view,
1478                                   elfcpp::Elf_types<64>::Elf_Addr address,
1479                                   section_size_type view_size)
1480 {
1481   if (this->skip_call_tls_get_addr_)
1482     {
1483       if (r_type != elfcpp::R_X86_64_PLT32
1484           || gsym == NULL
1485           || strcmp(gsym->name(), "__tls_get_addr") != 0)
1486         {
1487           gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1488                                  _("missing expected TLS relocation"));
1489         }
1490       else
1491         {
1492           this->skip_call_tls_get_addr_ = false;
1493           return false;
1494         }
1495     }
1496
1497   // Pick the value to use for symbols defined in shared objects.
1498   Symbol_value<64> symval;
1499   if (gsym != NULL
1500       && (gsym->is_from_dynobj()
1501           || (parameters->options().shared()
1502               && (gsym->is_undefined() || gsym->is_preemptible())))
1503       && gsym->has_plt_offset())
1504     {
1505       symval.set_output_value(target->plt_section()->address()
1506                               + gsym->plt_offset());
1507       psymval = &symval;
1508     }
1509
1510   const Sized_relobj<64, false>* object = relinfo->object;
1511   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1512
1513   // Get the GOT offset if needed.
1514   // The GOT pointer points to the end of the GOT section.
1515   // We need to subtract the size of the GOT section to get
1516   // the actual offset to use in the relocation.
1517   bool have_got_offset = false;
1518   unsigned int got_offset = 0;
1519   switch (r_type)
1520     {
1521     case elfcpp::R_X86_64_GOT32:
1522     case elfcpp::R_X86_64_GOT64:
1523     case elfcpp::R_X86_64_GOTPLT64:
1524     case elfcpp::R_X86_64_GOTPCREL:
1525     case elfcpp::R_X86_64_GOTPCREL64:
1526       if (gsym != NULL)
1527         {
1528           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1529           got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size();
1530         }
1531       else
1532         {
1533           unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1534           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1535           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1536                         - target->got_size());
1537         }
1538       have_got_offset = true;
1539       break;
1540
1541     default:
1542       break;
1543     }
1544
1545   switch (r_type)
1546     {
1547     case elfcpp::R_X86_64_NONE:
1548     case elfcpp::R_386_GNU_VTINHERIT:
1549     case elfcpp::R_386_GNU_VTENTRY:
1550       break;
1551
1552     case elfcpp::R_X86_64_64:
1553       Relocate_functions<64, false>::rela64(view, object, psymval, addend);
1554       break;
1555
1556     case elfcpp::R_X86_64_PC64:
1557       Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
1558                                               address);
1559       break;
1560
1561     case elfcpp::R_X86_64_32:
1562       // FIXME: we need to verify that value + addend fits into 32 bits:
1563       //    uint64_t x = value + addend;
1564       //    x == static_cast<uint64_t>(static_cast<uint32_t>(x))
1565       // Likewise for other <=32-bit relocations (but see R_X86_64_32S).
1566       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1567       break;
1568
1569     case elfcpp::R_X86_64_32S:
1570       // FIXME: we need to verify that value + addend fits into 32 bits:
1571       //    int64_t x = value + addend;   // note this quantity is signed!
1572       //    x == static_cast<int64_t>(static_cast<int32_t>(x))
1573       Relocate_functions<64, false>::rela32(view, object, psymval, addend);
1574       break;
1575
1576     case elfcpp::R_X86_64_PC32:
1577       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1578                                               address);
1579       break;
1580
1581     case elfcpp::R_X86_64_16:
1582       Relocate_functions<64, false>::rela16(view, object, psymval, addend);
1583       break;
1584
1585     case elfcpp::R_X86_64_PC16:
1586       Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
1587                                               address);
1588       break;
1589
1590     case elfcpp::R_X86_64_8:
1591       Relocate_functions<64, false>::rela8(view, object, psymval, addend);
1592       break;
1593
1594     case elfcpp::R_X86_64_PC8:
1595       Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
1596                                              address);
1597       break;
1598
1599     case elfcpp::R_X86_64_PLT32:
1600       gold_assert(gsym == NULL
1601                   || gsym->has_plt_offset()
1602                   || gsym->final_value_is_known()
1603                   || (gsym->is_defined()
1604                       && !gsym->is_from_dynobj()
1605                       && !gsym->is_preemptible()));
1606       // Note: while this code looks the same as for R_X86_64_PC32, it
1607       // behaves differently because psymval was set to point to
1608       // the PLT entry, rather than the symbol, in Scan::global().
1609       Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
1610                                               address);
1611       break;
1612
1613     case elfcpp::R_X86_64_PLTOFF64:
1614       {
1615         gold_assert(gsym);
1616         gold_assert(gsym->has_plt_offset()
1617                     || gsym->final_value_is_known());
1618         elfcpp::Elf_types<64>::Elf_Addr got_address;
1619         got_address = target->got_section(NULL, NULL)->address();
1620         Relocate_functions<64, false>::rela64(view, object, psymval,
1621                                               addend - got_address);
1622       }
1623
1624     case elfcpp::R_X86_64_GOT32:
1625       gold_assert(have_got_offset);
1626       Relocate_functions<64, false>::rela32(view, got_offset, addend);
1627       break;
1628
1629     case elfcpp::R_X86_64_GOTPC32:
1630       {
1631         gold_assert(gsym);
1632         elfcpp::Elf_types<64>::Elf_Addr value;
1633         value = target->got_plt_section()->address();
1634         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1635       }
1636       break;
1637
1638     case elfcpp::R_X86_64_GOT64:
1639       // The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
1640       // Since we always add a PLT entry, this is equivalent.
1641     case elfcpp::R_X86_64_GOTPLT64:
1642       gold_assert(have_got_offset);
1643       Relocate_functions<64, false>::rela64(view, got_offset, addend);
1644       break;
1645
1646     case elfcpp::R_X86_64_GOTPC64:
1647       {
1648         gold_assert(gsym);
1649         elfcpp::Elf_types<64>::Elf_Addr value;
1650         value = target->got_plt_section()->address();
1651         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1652       }
1653       break;
1654
1655     case elfcpp::R_X86_64_GOTOFF64:
1656       {
1657         elfcpp::Elf_types<64>::Elf_Addr value;
1658         value = (psymval->value(object, 0)
1659                  - target->got_plt_section()->address());
1660         Relocate_functions<64, false>::rela64(view, value, addend);
1661       }
1662       break;
1663
1664     case elfcpp::R_X86_64_GOTPCREL:
1665       {
1666         gold_assert(have_got_offset);
1667         elfcpp::Elf_types<64>::Elf_Addr value;
1668         value = target->got_plt_section()->address() + got_offset;
1669         Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1670       }
1671       break;
1672
1673     case elfcpp::R_X86_64_GOTPCREL64:
1674       {
1675         gold_assert(have_got_offset);
1676         elfcpp::Elf_types<64>::Elf_Addr value;
1677         value = target->got_plt_section()->address() + got_offset;
1678         Relocate_functions<64, false>::pcrela64(view, value, addend, address);
1679       }
1680       break;
1681
1682     case elfcpp::R_X86_64_COPY:
1683     case elfcpp::R_X86_64_GLOB_DAT:
1684     case elfcpp::R_X86_64_JUMP_SLOT:
1685     case elfcpp::R_X86_64_RELATIVE:
1686       // These are outstanding tls relocs, which are unexpected when linking
1687     case elfcpp::R_X86_64_TPOFF64:
1688     case elfcpp::R_X86_64_DTPMOD64:
1689     case elfcpp::R_X86_64_TLSDESC:
1690       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1691                              _("unexpected reloc %u in object file"),
1692                              r_type);
1693       break;
1694
1695       // These are initial tls relocs, which are expected when linking
1696     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1697     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1698     case elfcpp::R_X86_64_TLSDESC_CALL:
1699     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1700     case elfcpp::R_X86_64_DTPOFF32:
1701     case elfcpp::R_X86_64_DTPOFF64:
1702     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1703     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1704       this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
1705                          view, address, view_size);
1706       break;
1707
1708     case elfcpp::R_X86_64_SIZE32:
1709     case elfcpp::R_X86_64_SIZE64:
1710     default:
1711       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1712                              _("unsupported reloc %u"),
1713                              r_type);
1714       break;
1715     }
1716
1717   return true;
1718 }
1719
1720 // Perform a TLS relocation.
1721
1722 inline void
1723 Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
1724                                       Target_x86_64* target,
1725                                       size_t relnum,
1726                                       const elfcpp::Rela<64, false>& rela,
1727                                       unsigned int r_type,
1728                                       const Sized_symbol<64>* gsym,
1729                                       const Symbol_value<64>* psymval,
1730                                       unsigned char* view,
1731                                       elfcpp::Elf_types<64>::Elf_Addr address,
1732                                       section_size_type view_size)
1733 {
1734   Output_segment* tls_segment = relinfo->layout->tls_segment();
1735
1736   const Sized_relobj<64, false>* object = relinfo->object;
1737   const elfcpp::Elf_Xword addend = rela.get_r_addend();
1738
1739   elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
1740
1741   const bool is_final = (gsym == NULL
1742                          ? !parameters->options().output_is_position_independent()
1743                          : gsym->final_value_is_known());
1744   const tls::Tls_optimization optimized_type
1745       = Target_x86_64::optimize_tls_reloc(is_final, r_type);
1746   switch (r_type)
1747     {
1748     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
1749     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
1750     case elfcpp::R_X86_64_TLSDESC_CALL:
1751       if (optimized_type == tls::TLSOPT_TO_LE)
1752         {
1753           gold_assert(tls_segment != NULL);
1754           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1755                              rela, r_type, value, view,
1756                              view_size);
1757           break;
1758         }
1759       else
1760         {
1761           unsigned int got_offset;
1762           if (gsym != NULL)
1763             {
1764               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_PAIR));
1765               got_offset = (gsym->got_offset(GOT_TYPE_TLS_PAIR)
1766                             - target->got_size());
1767             }
1768           else
1769             {
1770               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1771               gold_assert(object->local_has_got_offset(r_sym,
1772                           GOT_TYPE_TLS_PAIR));
1773               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_PAIR)
1774                             - target->got_size());
1775             }
1776           if (optimized_type == tls::TLSOPT_TO_IE)
1777             {
1778               gold_assert(tls_segment != NULL);
1779               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
1780                                  got_offset, view, view_size);
1781               break;
1782             }
1783           else if (optimized_type == tls::TLSOPT_NONE)
1784             {
1785               // Relocate the field with the offset of the pair of GOT
1786               // entries.
1787               value = target->got_plt_section()->address() + got_offset;
1788               Relocate_functions<64, false>::pcrela32(view, value, addend,
1789                                                       address);
1790               break;
1791             }
1792         }
1793       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1794                              _("unsupported reloc %u"), r_type);
1795       break;
1796
1797     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
1798       if (optimized_type == tls::TLSOPT_TO_LE)
1799         {
1800           gold_assert(tls_segment != NULL);
1801           this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
1802                              value, view, view_size);
1803           break;
1804         }
1805       else if (optimized_type == tls::TLSOPT_NONE)
1806         {
1807           // Relocate the field with the offset of the GOT entry for
1808           // the module index.
1809           unsigned int got_offset;
1810           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
1811                         - target->got_size());
1812           value = target->got_plt_section()->address() + got_offset;
1813           Relocate_functions<64, false>::pcrela32(view, value, addend,
1814                                                   address);
1815           break;
1816         }
1817       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1818                              _("unsupported reloc %u"), r_type);
1819       break;
1820
1821     case elfcpp::R_X86_64_DTPOFF32:
1822       gold_assert(tls_segment != NULL);
1823       if (optimized_type == tls::TLSOPT_TO_LE)
1824         value -= tls_segment->memsz();
1825       Relocate_functions<64, false>::rela32(view, value, 0);
1826       break;
1827
1828     case elfcpp::R_X86_64_DTPOFF64:
1829       gold_assert(tls_segment != NULL);
1830       if (optimized_type == tls::TLSOPT_TO_LE)
1831         value -= tls_segment->memsz();
1832       Relocate_functions<64, false>::rela64(view, value, 0);
1833       break;
1834
1835     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
1836       if (optimized_type == tls::TLSOPT_TO_LE)
1837         {
1838           gold_assert(tls_segment != NULL);
1839           Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1840                                                 rela, r_type, value, view,
1841                                                 view_size);
1842           break;
1843         }
1844       else if (optimized_type == tls::TLSOPT_NONE)
1845         {
1846           // Relocate the field with the offset of the GOT entry for
1847           // the tp-relative offset of the symbol.
1848           unsigned int got_offset;
1849           if (gsym != NULL)
1850             {
1851               gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
1852               got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
1853                             - target->got_size());
1854             }
1855           else
1856             {
1857               unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
1858               gold_assert(object->local_has_got_offset(r_sym,
1859                                                        GOT_TYPE_TLS_OFFSET));
1860               got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
1861                             - target->got_size());
1862             }
1863           value = target->got_plt_section()->address() + got_offset;
1864           Relocate_functions<64, false>::pcrela32(view, value, addend, address);
1865           break;
1866         }
1867       gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
1868                              _("unsupported reloc type %u"),
1869                              r_type);
1870       break;
1871
1872     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
1873       value -= tls_segment->memsz();
1874       Relocate_functions<64, false>::rela32(view, value, 0);
1875       break;
1876     }
1877 }
1878
1879 // Do a relocation in which we convert a TLS General-Dynamic to an
1880 // Initial-Exec.
1881
1882 inline void
1883 Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
1884                                       size_t relnum,
1885                                       Output_segment* tls_segment,
1886                                       const elfcpp::Rela<64, false>& rela,
1887                                       unsigned int,
1888                                       elfcpp::Elf_types<64>::Elf_Addr value,
1889                                       unsigned char* view,
1890                                       section_size_type view_size)
1891 {
1892   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1893   // .word 0x6666; rex64; call __tls_get_addr
1894   // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
1895
1896   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1897   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1898
1899   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1900                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1901   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1902                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1903
1904   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
1905
1906   value -= tls_segment->memsz();
1907   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1908
1909   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1910   // We can skip it.
1911   this->skip_call_tls_get_addr_ = true;
1912 }
1913
1914 // Do a relocation in which we convert a TLS General-Dynamic to a
1915 // Local-Exec.
1916
1917 inline void
1918 Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
1919                                       size_t relnum,
1920                                       Output_segment* tls_segment,
1921                                       const elfcpp::Rela<64, false>& rela,
1922                                       unsigned int,
1923                                       elfcpp::Elf_types<64>::Elf_Addr value,
1924                                       unsigned char* view,
1925                                       section_size_type view_size)
1926 {
1927   // .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
1928   // .word 0x6666; rex64; call __tls_get_addr
1929   // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
1930
1931   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
1932   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
1933
1934   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1935                  (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
1936   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1937                  (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
1938
1939   memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
1940
1941   value -= tls_segment->memsz();
1942   Relocate_functions<64, false>::rela32(view + 8, value, 0);
1943
1944   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1945   // We can skip it.
1946   this->skip_call_tls_get_addr_ = true;
1947 }
1948
1949 inline void
1950 Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
1951                                       size_t relnum,
1952                                       Output_segment*,
1953                                       const elfcpp::Rela<64, false>& rela,
1954                                       unsigned int,
1955                                       elfcpp::Elf_types<64>::Elf_Addr,
1956                                       unsigned char* view,
1957                                       section_size_type view_size)
1958 {
1959   // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
1960   // ... leq foo@dtpoff(%rax),%reg
1961   // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
1962
1963   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1964   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
1965
1966   tls::check_tls(relinfo, relnum, rela.get_r_offset(),
1967                  view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
1968
1969   tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
1970
1971   memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
1972
1973   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1974   // We can skip it.
1975   this->skip_call_tls_get_addr_ = true;
1976 }
1977
1978 // Do a relocation in which we convert a TLS Initial-Exec to a
1979 // Local-Exec.
1980
1981 inline void
1982 Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
1983                                       size_t relnum,
1984                                       Output_segment* tls_segment,
1985                                       const elfcpp::Rela<64, false>& rela,
1986                                       unsigned int,
1987                                       elfcpp::Elf_types<64>::Elf_Addr value,
1988                                       unsigned char* view,
1989                                       section_size_type view_size)
1990 {
1991   // We need to examine the opcodes to figure out which instruction we
1992   // are looking at.
1993
1994   // movq foo@gottpoff(%rip),%reg  ==>  movq $YY,%reg
1995   // addq foo@gottpoff(%rip),%reg  ==>  addq $YY,%reg
1996
1997   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
1998   tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
1999
2000   unsigned char op1 = view[-3];
2001   unsigned char op2 = view[-2];
2002   unsigned char op3 = view[-1];
2003   unsigned char reg = op3 >> 3;
2004
2005   if (op2 == 0x8b)
2006     {
2007       // movq
2008       if (op1 == 0x4c)
2009         view[-3] = 0x49;
2010       view[-2] = 0xc7;
2011       view[-1] = 0xc0 | reg;
2012     }
2013   else if (reg == 4)
2014     {
2015       // Special handling for %rsp.
2016       if (op1 == 0x4c)
2017         view[-3] = 0x49;
2018       view[-2] = 0x81;
2019       view[-1] = 0xc0 | reg;
2020     }
2021   else
2022     {
2023       // addq
2024       if (op1 == 0x4c)
2025         view[-3] = 0x4d;
2026       view[-2] = 0x8d;
2027       view[-1] = 0x80 | reg | (reg << 3);
2028     }
2029
2030   value -= tls_segment->memsz();
2031   Relocate_functions<64, false>::rela32(view, value, 0);
2032 }
2033
2034 // Relocate section data.
2035
2036 void
2037 Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo,
2038                                 unsigned int sh_type,
2039                                 const unsigned char* prelocs,
2040                                 size_t reloc_count,
2041                                 Output_section* output_section,
2042                                 bool needs_special_offset_handling,
2043                                 unsigned char* view,
2044                                 elfcpp::Elf_types<64>::Elf_Addr address,
2045                                 section_size_type view_size)
2046 {
2047   gold_assert(sh_type == elfcpp::SHT_RELA);
2048
2049   gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
2050                          Target_x86_64::Relocate>(
2051     relinfo,
2052     this,
2053     prelocs,
2054     reloc_count,
2055     output_section,
2056     needs_special_offset_handling,
2057     view,
2058     address,
2059     view_size);
2060 }
2061
2062 // Return the size of a relocation while scanning during a relocatable
2063 // link.
2064
2065 unsigned int
2066 Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
2067     unsigned int r_type,
2068     Relobj* object)
2069 {
2070   switch (r_type)
2071     {
2072     case elfcpp::R_X86_64_NONE:
2073     case elfcpp::R_386_GNU_VTINHERIT:
2074     case elfcpp::R_386_GNU_VTENTRY:
2075     case elfcpp::R_X86_64_TLSGD:            // Global-dynamic
2076     case elfcpp::R_X86_64_GOTPC32_TLSDESC:  // Global-dynamic (from ~oliva url)
2077     case elfcpp::R_X86_64_TLSDESC_CALL:
2078     case elfcpp::R_X86_64_TLSLD:            // Local-dynamic
2079     case elfcpp::R_X86_64_DTPOFF32:
2080     case elfcpp::R_X86_64_DTPOFF64:
2081     case elfcpp::R_X86_64_GOTTPOFF:         // Initial-exec
2082     case elfcpp::R_X86_64_TPOFF32:          // Local-exec
2083       return 0;
2084
2085     case elfcpp::R_X86_64_64:
2086     case elfcpp::R_X86_64_PC64:
2087     case elfcpp::R_X86_64_GOTOFF64:
2088     case elfcpp::R_X86_64_GOTPC64:
2089     case elfcpp::R_X86_64_PLTOFF64:
2090     case elfcpp::R_X86_64_GOT64:
2091     case elfcpp::R_X86_64_GOTPCREL64:
2092     case elfcpp::R_X86_64_GOTPCREL:
2093     case elfcpp::R_X86_64_GOTPLT64:
2094       return 8;
2095
2096     case elfcpp::R_X86_64_32:
2097     case elfcpp::R_X86_64_32S:
2098     case elfcpp::R_X86_64_PC32:
2099     case elfcpp::R_X86_64_PLT32:
2100     case elfcpp::R_X86_64_GOTPC32:
2101     case elfcpp::R_X86_64_GOT32:
2102       return 4;
2103
2104     case elfcpp::R_X86_64_16:
2105     case elfcpp::R_X86_64_PC16:
2106       return 2;
2107
2108     case elfcpp::R_X86_64_8:
2109     case elfcpp::R_X86_64_PC8:
2110       return 1;
2111
2112     case elfcpp::R_X86_64_COPY:
2113     case elfcpp::R_X86_64_GLOB_DAT:
2114     case elfcpp::R_X86_64_JUMP_SLOT:
2115     case elfcpp::R_X86_64_RELATIVE:
2116       // These are outstanding tls relocs, which are unexpected when linking
2117     case elfcpp::R_X86_64_TPOFF64:
2118     case elfcpp::R_X86_64_DTPMOD64:
2119     case elfcpp::R_X86_64_TLSDESC:
2120       object->error(_("unexpected reloc %u in object file"), r_type);
2121       return 0;
2122
2123     case elfcpp::R_X86_64_SIZE32:
2124     case elfcpp::R_X86_64_SIZE64:
2125     default:
2126       object->error(_("unsupported reloc %u against local symbol"), r_type);
2127       return 0;
2128     }
2129 }
2130
2131 // Scan the relocs during a relocatable link.
2132
2133 void
2134 Target_x86_64::scan_relocatable_relocs(const General_options& options,
2135                                        Symbol_table* symtab,
2136                                        Layout* layout,
2137                                        Sized_relobj<64, false>* object,
2138                                        unsigned int data_shndx,
2139                                        unsigned int sh_type,
2140                                        const unsigned char* prelocs,
2141                                        size_t reloc_count,
2142                                        Output_section* output_section,
2143                                        bool needs_special_offset_handling,
2144                                        size_t local_symbol_count,
2145                                        const unsigned char* plocal_symbols,
2146                                        Relocatable_relocs* rr)
2147 {
2148   gold_assert(sh_type == elfcpp::SHT_RELA);
2149
2150   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
2151     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2152
2153   gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
2154       Scan_relocatable_relocs>(
2155     options,
2156     symtab,
2157     layout,
2158     object,
2159     data_shndx,
2160     prelocs,
2161     reloc_count,
2162     output_section,
2163     needs_special_offset_handling,
2164     local_symbol_count,
2165     plocal_symbols,
2166     rr);
2167 }
2168
2169 // Relocate a section during a relocatable link.
2170
2171 void
2172 Target_x86_64::relocate_for_relocatable(
2173     const Relocate_info<64, false>* relinfo,
2174     unsigned int sh_type,
2175     const unsigned char* prelocs,
2176     size_t reloc_count,
2177     Output_section* output_section,
2178     off_t offset_in_output_section,
2179     const Relocatable_relocs* rr,
2180     unsigned char* view,
2181     elfcpp::Elf_types<64>::Elf_Addr view_address,
2182     section_size_type view_size,
2183     unsigned char* reloc_view,
2184     section_size_type reloc_view_size)
2185 {
2186   gold_assert(sh_type == elfcpp::SHT_RELA);
2187
2188   gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
2189     relinfo,
2190     prelocs,
2191     reloc_count,
2192     output_section,
2193     offset_in_output_section,
2194     rr,
2195     view,
2196     view_address,
2197     view_size,
2198     reloc_view,
2199     reloc_view_size);
2200 }
2201
2202 // Return the value to use for a dynamic which requires special
2203 // treatment.  This is how we support equality comparisons of function
2204 // pointers across shared library boundaries, as described in the
2205 // processor specific ABI supplement.
2206
2207 uint64_t
2208 Target_x86_64::do_dynsym_value(const Symbol* gsym) const
2209 {
2210   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2211   return this->plt_section()->address() + gsym->plt_offset();
2212 }
2213
2214 // Return a string used to fill a code section with nops to take up
2215 // the specified length.
2216
2217 std::string
2218 Target_x86_64::do_code_fill(section_size_type length) const
2219 {
2220   if (length >= 16)
2221     {
2222       // Build a jmpq instruction to skip over the bytes.
2223       unsigned char jmp[5];
2224       jmp[0] = 0xe9;
2225       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2226       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2227               + std::string(length - 5, '\0'));
2228     }
2229
2230   // Nop sequences of various lengths.
2231   const char nop1[1] = { 0x90 };                   // nop
2232   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2233   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2234   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2235   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2236                          0x00 };                   // leal 0(%esi,1),%esi
2237   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2238                          0x00, 0x00 };
2239   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2240                          0x00, 0x00, 0x00 };
2241   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2242                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2243   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2244                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2245                          0x00 };
2246   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2247                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2248                            0x00, 0x00 };
2249   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2250                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2251                            0x00, 0x00, 0x00 };
2252   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2253                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2254                            0x00, 0x00, 0x00, 0x00 };
2255   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2256                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2257                            0x27, 0x00, 0x00, 0x00,
2258                            0x00 };
2259   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2260                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2261                            0xbc, 0x27, 0x00, 0x00,
2262                            0x00, 0x00 };
2263   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2264                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2265                            0x90, 0x90, 0x90, 0x90,
2266                            0x90, 0x90, 0x90 };
2267
2268   const char* nops[16] = {
2269     NULL,
2270     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2271     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2272   };
2273
2274   return std::string(nops[length], length);
2275 }
2276
2277 // The selector for x86_64 object files.
2278
2279 class Target_selector_x86_64 : public Target_selector
2280 {
2281 public:
2282   Target_selector_x86_64()
2283     : Target_selector(elfcpp::EM_X86_64, 64, false, "elf64-x86-64")
2284   { }
2285
2286   Target*
2287   do_instantiate_target()
2288   { return new Target_x86_64(); }
2289 };
2290
2291 Target_selector_x86_64 target_selector_x86_64;
2292
2293 } // End anonymous namespace.