gold/i386.cc

   1 // i386.cc -- i386 target support for gold.
   2
   3 // Copyright 2006, 2007 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 "i386.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_i386;
  46
  47 // The i386 target class.
  48 // TLS info comes from
  49 //   http://people.redhat.com/drepper/tls.pdf
  50 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  51
  52 class Target_i386 : public Sized_target<32, false>
  53 {
  54  public:
  55   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
  56
  57   Target_i386()
  58     : Sized_target<32, false>(&i386_info),
  59       got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
  60       copy_relocs_(NULL), dynbss_(NULL)
  61   { }
  62
  63   // Scan the relocations to look for symbol adjustments.
  64   void
  65   scan_relocs(const General_options& options,
  66               Symbol_table* symtab,
  67               Layout* layout,
  68               Sized_relobj<32, false>* object,
  69               unsigned int data_shndx,
  70               unsigned int sh_type,
  71               const unsigned char* prelocs,
  72               size_t reloc_count,
  73               Output_section* output_section,
  74               bool needs_special_offset_handling,
  75               size_t local_symbol_count,
  76               const unsigned char* plocal_symbols);
  77
  78   // Finalize the sections.
  79   void
  80   do_finalize_sections(Layout*);
  81
  82   // Return the value to use for a dynamic which requires special
  83   // treatment.
  84   uint64_t
  85   do_dynsym_value(const Symbol*) const;
  86
  87   // Relocate a section.
  88   void
  89   relocate_section(const Relocate_info<32, false>*,
  90                    unsigned int sh_type,
  91                    const unsigned char* prelocs,
  92                    size_t reloc_count,
  93                    Output_section* output_section,
  94                    bool needs_special_offset_handling,
  95                    unsigned char* view,
  96                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  97                    off_t view_size);
  98
  99   // Return a string used to fill a code section with nops.
 100   std::string
 101   do_code_fill(off_t length);
 102
 103   // Return whether SYM is defined by the ABI.
 104   bool
 105   do_is_defined_by_abi(Symbol* sym) const
 106   { return strcmp(sym->name(), "___tls_get_addr") == 0; }
 107
 108   // Return the size of the GOT section.
 109   off_t
 110   got_size()
 111   {
 112     gold_assert(this->got_ != NULL);
 113     return this->got_->data_size();
 114   }
 115
 116  private:
 117   // The class which scans relocations.
 118   struct Scan
 119   {
 120     inline void
 121     local(const General_options& options, Symbol_table* symtab,
 122           Layout* layout, Target_i386* target,
 123           Sized_relobj<32, false>* object,
 124           unsigned int data_shndx,
 125           Output_section* output_section,
 126           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 127           const elfcpp::Sym<32, false>& lsym);
 128
 129     inline void
 130     global(const General_options& options, Symbol_table* symtab,
 131            Layout* layout, Target_i386* target,
 132            Sized_relobj<32, false>* object,
 133            unsigned int data_shndx,
 134            Output_section* output_section,
 135            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 136            Symbol* gsym);
 137
 138     static void
 139     unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
 140
 141     static void
 142     unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
 143                              Symbol*);
 144   };
 145
 146   // The class which implements relocation.
 147   class Relocate
 148   {
 149    public:
 150     Relocate()
 151       : skip_call_tls_get_addr_(false),
 152         local_dynamic_type_(LOCAL_DYNAMIC_NONE)
 153     { }
 154
 155     ~Relocate()
 156     {
 157       if (this->skip_call_tls_get_addr_)
 158         {
 159           // FIXME: This needs to specify the location somehow.
 160           gold_error(_("missing expected TLS relocation"));
 161         }
 162     }
 163
 164     // Return whether the static relocation needs to be applied.
 165     inline bool
 166     should_apply_static_reloc(const Sized_symbol<32>* gsym,
 167                               bool is_absolute_ref,
 168                               bool is_function_call,
 169                               bool is_32bit);
 170
 171     // Do a relocation.  Return false if the caller should not issue
 172     // any warnings about this relocation.
 173     inline bool
 174     relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
 175              const elfcpp::Rel<32, false>&,
 176              unsigned int r_type, const Sized_symbol<32>*,
 177              const Symbol_value<32>*,
 178              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 179              off_t);
 180
 181    private:
 182     // Do a TLS relocation.
 183     inline void
 184     relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
 185                  size_t relnum, const elfcpp::Rel<32, false>&,
 186                  unsigned int r_type, const Sized_symbol<32>*,
 187                  const Symbol_value<32>*,
 188                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
 189
 190     // Do a TLS General-Dynamic to Initial-Exec transition.
 191     inline void
 192     tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
 193                  Output_segment* tls_segment,
 194                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 195                  elfcpp::Elf_types<32>::Elf_Addr value,
 196                  unsigned char* view,
 197                  off_t view_size);
 198
 199     // Do a TLS General-Dynamic to Local-Exec transition.
 200     inline void
 201     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 202                  Output_segment* tls_segment,
 203                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 204                  elfcpp::Elf_types<32>::Elf_Addr value,
 205                  unsigned char* view,
 206                  off_t view_size);
 207
 208     // Do a TLS Local-Dynamic to Local-Exec transition.
 209     inline void
 210     tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
 211                  Output_segment* tls_segment,
 212                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 213                  elfcpp::Elf_types<32>::Elf_Addr value,
 214                  unsigned char* view,
 215                  off_t view_size);
 216
 217     // Do a TLS Initial-Exec to Local-Exec transition.
 218     static inline void
 219     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 220                  Output_segment* tls_segment,
 221                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 222                  elfcpp::Elf_types<32>::Elf_Addr value,
 223                  unsigned char* view,
 224                  off_t view_size);
 225
 226     // We need to keep track of which type of local dynamic relocation
 227     // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
 228     enum Local_dynamic_type
 229     {
 230       LOCAL_DYNAMIC_NONE,
 231       LOCAL_DYNAMIC_SUN,
 232       LOCAL_DYNAMIC_GNU
 233     };
 234
 235     // This is set if we should skip the next reloc, which should be a
 236     // PLT32 reloc against ___tls_get_addr.
 237     bool skip_call_tls_get_addr_;
 238     // The type of local dynamic relocation we have seen in the section
 239     // being relocated, if any.
 240     Local_dynamic_type local_dynamic_type_;
 241   };
 242
 243   // Adjust TLS relocation type based on the options and whether this
 244   // is a local symbol.
 245   static tls::Tls_optimization
 246   optimize_tls_reloc(bool is_final, int r_type);
 247
 248   // Get the GOT section, creating it if necessary.
 249   Output_data_got<32, false>*
 250   got_section(Symbol_table*, Layout*);
 251
 252   // Get the GOT PLT section.
 253   Output_data_space*
 254   got_plt_section() const
 255   {
 256     gold_assert(this->got_plt_ != NULL);
 257     return this->got_plt_;
 258   }
 259
 260   // Create a PLT entry for a global symbol.
 261   void
 262   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 263
 264   // Get the PLT section.
 265   const Output_data_plt_i386*
 266   plt_section() const
 267   {
 268     gold_assert(this->plt_ != NULL);
 269     return this->plt_;
 270   }
 271
 272   // Get the dynamic reloc section, creating it if necessary.
 273   Reloc_section*
 274   rel_dyn_section(Layout*);
 275
 276   // Return true if the symbol may need a COPY relocation.
 277   // References from an executable object to non-function symbols
 278   // defined in a dynamic object may need a COPY relocation.
 279   bool
 280   may_need_copy_reloc(Symbol* gsym)
 281   {
 282     return (!parameters->output_is_shared()
 283             && gsym->is_from_dynobj()
 284             && gsym->type() != elfcpp::STT_FUNC);
 285   }
 286
 287   // Copy a relocation against a global symbol.
 288   void
 289   copy_reloc(const General_options*, Symbol_table*, Layout*,
 290              Sized_relobj<32, false>*, unsigned int,
 291              Output_section*, Symbol*, const elfcpp::Rel<32, false>&);
 292
 293   // Information about this specific target which we pass to the
 294   // general Target structure.
 295   static const Target::Target_info i386_info;
 296
 297   // The GOT section.
 298   Output_data_got<32, false>* got_;
 299   // The PLT section.
 300   Output_data_plt_i386* plt_;
 301   // The GOT PLT section.
 302   Output_data_space* got_plt_;
 303   // The dynamic reloc section.
 304   Reloc_section* rel_dyn_;
 305   // Relocs saved to avoid a COPY reloc.
 306   Copy_relocs<32, false>* copy_relocs_;
 307   // Space for variables copied with a COPY reloc.
 308   Output_data_space* dynbss_;
 309 };
 310
 311 const Target::Target_info Target_i386::i386_info =
 312 {
 313   32,                   // size
 314   false,                // is_big_endian
 315   elfcpp::EM_386,       // machine_code
 316   false,                // has_make_symbol
 317   false,                // has_resolve
 318   true,                 // has_code_fill
 319   true,                 // is_default_stack_executable
 320   "/usr/lib/libc.so.1", // dynamic_linker
 321   0x08048000,           // default_text_segment_address
 322   0x1000,               // abi_pagesize
 323   0x1000                // common_pagesize
 324 };
 325
 326 // Get the GOT section, creating it if necessary.
 327
 328 Output_data_got<32, false>*
 329 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 330 {
 331   if (this->got_ == NULL)
 332     {
 333       gold_assert(symtab != NULL && layout != NULL);
 334
 335       this->got_ = new Output_data_got<32, false>();
 336
 337       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 338                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 339                                       this->got_);
 340
 341       // The old GNU linker creates a .got.plt section.  We just
 342       // create another set of data in the .got section.  Note that we
 343       // always create a PLT if we create a GOT, although the PLT
 344       // might be empty.
 345       this->got_plt_ = new Output_data_space(4);
 346       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 347                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 348                                       this->got_plt_);
 349
 350       // The first three entries are reserved.
 351       this->got_plt_->set_current_data_size(3 * 4);
 352
 353       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 354       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 355                                     this->got_plt_,
 356                                     0, 0, elfcpp::STT_OBJECT,
 357                                     elfcpp::STB_LOCAL,
 358                                     elfcpp::STV_HIDDEN, 0,
 359                                     false, false);
 360     }
 361
 362   return this->got_;
 363 }
 364
 365 // Get the dynamic reloc section, creating it if necessary.
 366
 367 Target_i386::Reloc_section*
 368 Target_i386::rel_dyn_section(Layout* layout)
 369 {
 370   if (this->rel_dyn_ == NULL)
 371     {
 372       gold_assert(layout != NULL);
 373       this->rel_dyn_ = new Reloc_section();
 374       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 375                                       elfcpp::SHF_ALLOC, this->rel_dyn_);
 376     }
 377   return this->rel_dyn_;
 378 }
 379
 380 // A class to handle the PLT data.
 381
 382 class Output_data_plt_i386 : public Output_section_data
 383 {
 384  public:
 385   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 386
 387   Output_data_plt_i386(Layout*, Output_data_space*);
 388
 389   // Add an entry to the PLT.
 390   void
 391   add_entry(Symbol* gsym);
 392
 393   // Return the .rel.plt section data.
 394   const Reloc_section*
 395   rel_plt() const
 396   { return this->rel_; }
 397
 398  protected:
 399   void
 400   do_adjust_output_section(Output_section* os);
 401
 402  private:
 403   // The size of an entry in the PLT.
 404   static const int plt_entry_size = 16;
 405
 406   // The first entry in the PLT for an executable.
 407   static unsigned char exec_first_plt_entry[plt_entry_size];
 408
 409   // The first entry in the PLT for a shared object.
 410   static unsigned char dyn_first_plt_entry[plt_entry_size];
 411
 412   // Other entries in the PLT for an executable.
 413   static unsigned char exec_plt_entry[plt_entry_size];
 414
 415   // Other entries in the PLT for a shared object.
 416   static unsigned char dyn_plt_entry[plt_entry_size];
 417
 418   // Set the final size.
 419   void
 420   set_final_data_size()
 421   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 422
 423   // Write out the PLT data.
 424   void
 425   do_write(Output_file*);
 426
 427   // The reloc section.
 428   Reloc_section* rel_;
 429   // The .got.plt section.
 430   Output_data_space* got_plt_;
 431   // The number of PLT entries.
 432   unsigned int count_;
 433 };
 434
 435 // Create the PLT section.  The ordinary .got section is an argument,
 436 // since we need to refer to the start.  We also create our own .got
 437 // section just for PLT entries.
 438
 439 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 440                                            Output_data_space* got_plt)
 441   : Output_section_data(4), got_plt_(got_plt), count_(0)
 442 {
 443   this->rel_ = new Reloc_section();
 444   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 445                                   elfcpp::SHF_ALLOC, this->rel_);
 446 }
 447
 448 void
 449 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 450 {
 451   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 452   // linker, and so do we.
 453   os->set_entsize(4);
 454 }
 455
 456 // Add an entry to the PLT.
 457
 458 void
 459 Output_data_plt_i386::add_entry(Symbol* gsym)
 460 {
 461   gold_assert(!gsym->has_plt_offset());
 462
 463   // Note that when setting the PLT offset we skip the initial
 464   // reserved PLT entry.
 465   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 466
 467   ++this->count_;
 468
 469   off_t got_offset = this->got_plt_->current_data_size();
 470
 471   // Every PLT entry needs a GOT entry which points back to the PLT
 472   // entry (this will be changed by the dynamic linker, normally
 473   // lazily when the function is called).
 474   this->got_plt_->set_current_data_size(got_offset + 4);
 475
 476   // Every PLT entry needs a reloc.
 477   gsym->set_needs_dynsym_entry();
 478   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 479                          got_offset);
 480
 481   // Note that we don't need to save the symbol.  The contents of the
 482   // PLT are independent of which symbols are used.  The symbols only
 483   // appear in the relocations.
 484 }
 485
 486 // The first entry in the PLT for an executable.
 487
 488 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 489 {
 490   0xff, 0x35,   // pushl contents of memory address
 491   0, 0, 0, 0,   // replaced with address of .got + 4
 492   0xff, 0x25,   // jmp indirect
 493   0, 0, 0, 0,   // replaced with address of .got + 8
 494   0, 0, 0, 0    // unused
 495 };
 496
 497 // The first entry in the PLT for a shared object.
 498
 499 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 500 {
 501   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 502   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 503   0, 0, 0, 0                    // unused
 504 };
 505
 506 // Subsequent entries in the PLT for an executable.
 507
 508 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 509 {
 510   0xff, 0x25,   // jmp indirect
 511   0, 0, 0, 0,   // replaced with address of symbol in .got
 512   0x68,         // pushl immediate
 513   0, 0, 0, 0,   // replaced with offset into relocation table
 514   0xe9,         // jmp relative
 515   0, 0, 0, 0    // replaced with offset to start of .plt
 516 };
 517
 518 // Subsequent entries in the PLT for a shared object.
 519
 520 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 521 {
 522   0xff, 0xa3,   // jmp *offset(%ebx)
 523   0, 0, 0, 0,   // replaced with offset of symbol in .got
 524   0x68,         // pushl immediate
 525   0, 0, 0, 0,   // replaced with offset into relocation table
 526   0xe9,         // jmp relative
 527   0, 0, 0, 0    // replaced with offset to start of .plt
 528 };
 529
 530 // Write out the PLT.  This uses the hand-coded instructions above,
 531 // and adjusts them as needed.  This is all specified by the i386 ELF
 532 // Processor Supplement.
 533
 534 void
 535 Output_data_plt_i386::do_write(Output_file* of)
 536 {
 537   const off_t offset = this->offset();
 538   const off_t oview_size = this->data_size();
 539   unsigned char* const oview = of->get_output_view(offset, oview_size);
 540
 541   const off_t got_file_offset = this->got_plt_->offset();
 542   const off_t got_size = this->got_plt_->data_size();
 543   unsigned char* const got_view = of->get_output_view(got_file_offset,
 544                                                       got_size);
 545
 546   unsigned char* pov = oview;
 547
 548   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 549   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 550
 551   if (parameters->output_is_shared())
 552     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 553   else
 554     {
 555       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 556       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 557       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 558     }
 559   pov += plt_entry_size;
 560
 561   unsigned char* got_pov = got_view;
 562
 563   memset(got_pov, 0, 12);
 564   got_pov += 12;
 565
 566   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 567
 568   unsigned int plt_offset = plt_entry_size;
 569   unsigned int plt_rel_offset = 0;
 570   unsigned int got_offset = 12;
 571   const unsigned int count = this->count_;
 572   for (unsigned int i = 0;
 573        i < count;
 574        ++i,
 575          pov += plt_entry_size,
 576          got_pov += 4,
 577          plt_offset += plt_entry_size,
 578          plt_rel_offset += rel_size,
 579          got_offset += 4)
 580     {
 581       // Set and adjust the PLT entry itself.
 582
 583       if (parameters->output_is_shared())
 584         {
 585           memcpy(pov, dyn_plt_entry, plt_entry_size);
 586           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 587         }
 588       else
 589         {
 590           memcpy(pov, exec_plt_entry, plt_entry_size);
 591           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 592                                                       (got_address
 593                                                        + got_offset));
 594         }
 595
 596       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 597       elfcpp::Swap<32, false>::writeval(pov + 12,
 598                                         - (plt_offset + plt_entry_size));
 599
 600       // Set the entry in the GOT.
 601       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 602     }
 603
 604   gold_assert(pov - oview == oview_size);
 605   gold_assert(got_pov - got_view == got_size);
 606
 607   of->write_output_view(offset, oview_size, oview);
 608   of->write_output_view(got_file_offset, got_size, got_view);
 609 }
 610
 611 // Create a PLT entry for a global symbol.
 612
 613 void
 614 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 615 {
 616   if (gsym->has_plt_offset())
 617     return;
 618
 619   if (this->plt_ == NULL)
 620     {
 621       // Create the GOT sections first.
 622       this->got_section(symtab, layout);
 623
 624       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 625       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 626                                       (elfcpp::SHF_ALLOC
 627                                        | elfcpp::SHF_EXECINSTR),
 628                                       this->plt_);
 629     }
 630
 631   this->plt_->add_entry(gsym);
 632 }
 633
 634 // Handle a relocation against a non-function symbol defined in a
 635 // dynamic object.  The traditional way to handle this is to generate
 636 // a COPY relocation to copy the variable at runtime from the shared
 637 // object into the executable's data segment.  However, this is
 638 // undesirable in general, as if the size of the object changes in the
 639 // dynamic object, the executable will no longer work correctly.  If
 640 // this relocation is in a writable section, then we can create a
 641 // dynamic reloc and the dynamic linker will resolve it to the correct
 642 // address at runtime.  However, we do not want do that if the
 643 // relocation is in a read-only section, as it would prevent the
 644 // readonly segment from being shared.  And if we have to eventually
 645 // generate a COPY reloc, then any dynamic relocations will be
 646 // useless.  So this means that if this is a writable section, we need
 647 // to save the relocation until we see whether we have to create a
 648 // COPY relocation for this symbol for any other relocation.
 649
 650 void
 651 Target_i386::copy_reloc(const General_options* options,
 652                         Symbol_table* symtab,
 653                         Layout* layout,
 654                         Sized_relobj<32, false>* object,
 655                         unsigned int data_shndx,
 656                         Output_section* output_section,
 657                         Symbol* gsym,
 658                         const elfcpp::Rel<32, false>& rel)
 659 {
 660   Sized_symbol<32>* ssym;
 661   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
 662                                                         SELECT_SIZE(32));
 663
 664   if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
 665                                                data_shndx, ssym))
 666     {
 667       // So far we do not need a COPY reloc.  Save this relocation.
 668       // If it turns out that we never need a COPY reloc for this
 669       // symbol, then we will emit the relocation.
 670       if (this->copy_relocs_ == NULL)
 671         this->copy_relocs_ = new Copy_relocs<32, false>();
 672       this->copy_relocs_->save(ssym, object, data_shndx, output_section, rel);
 673     }
 674   else
 675     {
 676       // Allocate space for this symbol in the .bss section.
 677
 678       elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
 679
 680       // There is no defined way to determine the required alignment
 681       // of the symbol.  We pick the alignment based on the size.  We
 682       // set an arbitrary maximum of 256.
 683       unsigned int align;
 684       for (align = 1; align < 512; align <<= 1)
 685         if ((symsize & align) != 0)
 686           break;
 687
 688       if (this->dynbss_ == NULL)
 689         {
 690           this->dynbss_ = new Output_data_space(align);
 691           layout->add_output_section_data(".bss",
 692                                           elfcpp::SHT_NOBITS,
 693                                           (elfcpp::SHF_ALLOC
 694                                            | elfcpp::SHF_WRITE),
 695                                           this->dynbss_);
 696         }
 697
 698       Output_data_space* dynbss = this->dynbss_;
 699
 700       if (align > dynbss->addralign())
 701         dynbss->set_space_alignment(align);
 702
 703       off_t dynbss_size = dynbss->current_data_size();
 704       dynbss_size = align_address(dynbss_size, align);
 705       off_t offset = dynbss_size;
 706       dynbss->set_current_data_size(dynbss_size + symsize);
 707
 708       symtab->define_with_copy_reloc(this, ssym, dynbss, offset);
 709
 710       // Add the COPY reloc.
 711       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 712       rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
 713     }
 714 }
 715
 716 // Optimize the TLS relocation type based on what we know about the
 717 // symbol.  IS_FINAL is true if the final address of this symbol is
 718 // known at link time.
 719
 720 tls::Tls_optimization
 721 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 722 {
 723   // If we are generating a shared library, then we can't do anything
 724   // in the linker.
 725   if (parameters->output_is_shared())
 726     return tls::TLSOPT_NONE;
 727
 728   switch (r_type)
 729     {
 730     case elfcpp::R_386_TLS_GD:
 731     case elfcpp::R_386_TLS_GOTDESC:
 732     case elfcpp::R_386_TLS_DESC_CALL:
 733       // These are General-Dynamic which permits fully general TLS
 734       // access.  Since we know that we are generating an executable,
 735       // we can convert this to Initial-Exec.  If we also know that
 736       // this is a local symbol, we can further switch to Local-Exec.
 737       if (is_final)
 738         return tls::TLSOPT_TO_LE;
 739       return tls::TLSOPT_TO_IE;
 740
 741     case elfcpp::R_386_TLS_LDM:
 742       // This is Local-Dynamic, which refers to a local symbol in the
 743       // dynamic TLS block.  Since we know that we generating an
 744       // executable, we can switch to Local-Exec.
 745       return tls::TLSOPT_TO_LE;
 746
 747     case elfcpp::R_386_TLS_LDO_32:
 748       // Another type of Local-Dynamic relocation.
 749       return tls::TLSOPT_TO_LE;
 750
 751     case elfcpp::R_386_TLS_IE:
 752     case elfcpp::R_386_TLS_GOTIE:
 753     case elfcpp::R_386_TLS_IE_32:
 754       // These are Initial-Exec relocs which get the thread offset
 755       // from the GOT.  If we know that we are linking against the
 756       // local symbol, we can switch to Local-Exec, which links the
 757       // thread offset into the instruction.
 758       if (is_final)
 759         return tls::TLSOPT_TO_LE;
 760       return tls::TLSOPT_NONE;
 761
 762     case elfcpp::R_386_TLS_LE:
 763     case elfcpp::R_386_TLS_LE_32:
 764       // When we already have Local-Exec, there is nothing further we
 765       // can do.
 766       return tls::TLSOPT_NONE;
 767
 768     default:
 769       gold_unreachable();
 770     }
 771 }
 772
 773 // Report an unsupported relocation against a local symbol.
 774
 775 void
 776 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
 777                                            unsigned int r_type)
 778 {
 779   gold_error(_("%s: unsupported reloc %u against local symbol"),
 780              object->name().c_str(), r_type);
 781 }
 782
 783 // Scan a relocation for a local symbol.
 784
 785 inline void
 786 Target_i386::Scan::local(const General_options&,
 787                          Symbol_table* symtab,
 788                          Layout* layout,
 789                          Target_i386* target,
 790                          Sized_relobj<32, false>* object,
 791                          unsigned int data_shndx,
 792                          Output_section* output_section,
 793                          const elfcpp::Rel<32, false>& reloc,
 794                          unsigned int r_type,
 795                          const elfcpp::Sym<32, false>&)
 796 {
 797   switch (r_type)
 798     {
 799     case elfcpp::R_386_NONE:
 800     case elfcpp::R_386_GNU_VTINHERIT:
 801     case elfcpp::R_386_GNU_VTENTRY:
 802       break;
 803
 804     case elfcpp::R_386_32:
 805       // If building a shared library (or a position-independent
 806       // executable), we need to create a dynamic relocation for
 807       // this location. The relocation applied at link time will
 808       // apply the link-time value, so we flag the location with
 809       // an R_386_RELATIVE relocation so the dynamic loader can
 810       // relocate it easily.
 811       if (parameters->output_is_position_independent())
 812         {
 813           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 814           rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, output_section,
 815                              data_shndx, reloc.get_r_offset());
 816         }
 817       break;
 818
 819     case elfcpp::R_386_16:
 820     case elfcpp::R_386_8:
 821       // If building a shared library (or a position-independent
 822       // executable), we need to create a dynamic relocation for
 823       // this location. Because the addend needs to remain in the
 824       // data section, we need to be careful not to apply this
 825       // relocation statically.
 826       if (parameters->output_is_position_independent())
 827         {
 828           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 829           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 830           rel_dyn->add_local(object, r_sym, r_type, output_section, data_shndx,
 831                              reloc.get_r_offset());
 832         }
 833       break;
 834
 835     case elfcpp::R_386_PC32:
 836     case elfcpp::R_386_PC16:
 837     case elfcpp::R_386_PC8:
 838       break;
 839
 840     case elfcpp::R_386_PLT32:
 841       // Since we know this is a local symbol, we can handle this as a
 842       // PC32 reloc.
 843       break;
 844
 845     case elfcpp::R_386_GOTOFF:
 846     case elfcpp::R_386_GOTPC:
 847       // We need a GOT section.
 848       target->got_section(symtab, layout);
 849       break;
 850
 851     case elfcpp::R_386_GOT32:
 852       {
 853         // The symbol requires a GOT entry.
 854         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 855         unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 856         if (got->add_local(object, r_sym))
 857           {
 858             // If we are generating a shared object, we need to add a
 859             // dynamic RELATIVE relocation for this symbol.
 860             if (parameters->output_is_position_independent())
 861               {
 862                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 863                 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
 864                                    output_section, data_shndx,
 865                                    reloc.get_r_offset());
 866               }
 867           }
 868       }
 869       break;
 870
 871       // These are relocations which should only be seen by the
 872       // dynamic linker, and should never be seen here.
 873     case elfcpp::R_386_COPY:
 874     case elfcpp::R_386_GLOB_DAT:
 875     case elfcpp::R_386_JUMP_SLOT:
 876     case elfcpp::R_386_RELATIVE:
 877     case elfcpp::R_386_TLS_TPOFF:
 878     case elfcpp::R_386_TLS_DTPMOD32:
 879     case elfcpp::R_386_TLS_DTPOFF32:
 880     case elfcpp::R_386_TLS_TPOFF32:
 881     case elfcpp::R_386_TLS_DESC:
 882       gold_error(_("%s: unexpected reloc %u in object file"),
 883                  object->name().c_str(), r_type);
 884       break;
 885
 886       // These are initial TLS relocs, which are expected when
 887       // linking.
 888     case elfcpp::R_386_TLS_GD:            // Global-dynamic
 889     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
 890     case elfcpp::R_386_TLS_DESC_CALL:
 891     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
 892     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
 893     case elfcpp::R_386_TLS_IE:            // Initial-exec
 894     case elfcpp::R_386_TLS_IE_32:
 895     case elfcpp::R_386_TLS_GOTIE:
 896     case elfcpp::R_386_TLS_LE:            // Local-exec
 897     case elfcpp::R_386_TLS_LE_32:
 898       {
 899         bool output_is_shared = parameters->output_is_shared();
 900         const tls::Tls_optimization optimized_type
 901             = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
 902         switch (r_type)
 903           {
 904           case elfcpp::R_386_TLS_GD:          // Global-dynamic
 905             if (optimized_type == tls::TLSOPT_NONE)
 906               {
 907                 // Create a pair of GOT entries for the module index and
 908                 // dtv-relative offset.
 909                 Output_data_got<32, false>* got
 910                     = target->got_section(symtab, layout);
 911                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 912                 if (got->add_local_tls(object, r_sym, true))
 913                   {
 914                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 915                     unsigned int got_off
 916                         = object->local_tls_got_offset(r_sym, true);
 917                     rel_dyn->add_local(object, r_sym,
 918                                        elfcpp::R_386_TLS_DTPMOD32,
 919                                        got, got_off);
 920                     rel_dyn->add_local(object, r_sym,
 921                                        elfcpp::R_386_TLS_DTPOFF32,
 922                                        got, got_off + 4);
 923                   }
 924               }
 925             else if (optimized_type != tls::TLSOPT_TO_LE)
 926               unsupported_reloc_local(object, r_type);
 927             break;
 928
 929           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (from ~oliva)
 930           case elfcpp::R_386_TLS_DESC_CALL:
 931             unsupported_reloc_local(object, r_type);
 932             break;
 933
 934           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
 935             if (optimized_type == tls::TLSOPT_NONE)
 936               {
 937                 // Create a GOT entry for the module index.
 938                 Output_data_got<32, false>* got
 939                     = target->got_section(symtab, layout);
 940                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 941                 if (got->add_local_tls(object, r_sym, false))
 942                   {
 943                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 944                     unsigned int got_off
 945                         = object->local_tls_got_offset(r_sym, false);
 946                     rel_dyn->add_local(object, r_sym,
 947                                        elfcpp::R_386_TLS_DTPMOD32, got,
 948                                        got_off);
 949                   }
 950               }
 951             else if (optimized_type != tls::TLSOPT_TO_LE)
 952               unsupported_reloc_local(object, r_type);
 953             break;
 954
 955           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
 956             break;
 957
 958           case elfcpp::R_386_TLS_IE:          // Initial-exec
 959           case elfcpp::R_386_TLS_IE_32:
 960           case elfcpp::R_386_TLS_GOTIE:
 961             if (optimized_type == tls::TLSOPT_NONE)
 962               {
 963                 // Create a GOT entry for the tp-relative offset.
 964                 Output_data_got<32, false>* got
 965                     = target->got_section(symtab, layout);
 966                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 967                 if (got->add_local(object, r_sym))
 968                   {
 969                     unsigned int dyn_r_type
 970                         = (r_type == elfcpp::R_386_TLS_IE_32
 971                            ? elfcpp::R_386_TLS_TPOFF32
 972                            : elfcpp::R_386_TLS_TPOFF);
 973                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 974                     unsigned int got_off = object->local_got_offset(r_sym);
 975                     rel_dyn->add_local(object, r_sym, dyn_r_type, got,
 976                                        got_off);
 977                   }
 978               }
 979             else if (optimized_type != tls::TLSOPT_TO_LE)
 980               unsupported_reloc_local(object, r_type);
 981             break;
 982
 983           case elfcpp::R_386_TLS_LE:          // Local-exec
 984           case elfcpp::R_386_TLS_LE_32:
 985             if (output_is_shared)
 986               unsupported_reloc_local(object, r_type);
 987             break;
 988
 989           default:
 990             gold_unreachable();
 991           }
 992       }
 993       break;
 994
 995     case elfcpp::R_386_32PLT:
 996     case elfcpp::R_386_TLS_GD_32:
 997     case elfcpp::R_386_TLS_GD_PUSH:
 998     case elfcpp::R_386_TLS_GD_CALL:
 999     case elfcpp::R_386_TLS_GD_POP:
1000     case elfcpp::R_386_TLS_LDM_32:
1001     case elfcpp::R_386_TLS_LDM_PUSH:
1002     case elfcpp::R_386_TLS_LDM_CALL:
1003     case elfcpp::R_386_TLS_LDM_POP:
1004     case elfcpp::R_386_USED_BY_INTEL_200:
1005     default:
1006       unsupported_reloc_local(object, r_type);
1007       break;
1008     }
1009 }
1010
1011 // Report an unsupported relocation against a global symbol.
1012
1013 void
1014 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1015                                             unsigned int r_type,
1016                                             Symbol* gsym)
1017 {
1018   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1019              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1020 }
1021
1022 // Scan a relocation for a global symbol.
1023
1024 inline void
1025 Target_i386::Scan::global(const General_options& options,
1026                           Symbol_table* symtab,
1027                           Layout* layout,
1028                           Target_i386* target,
1029                           Sized_relobj<32, false>* object,
1030                           unsigned int data_shndx,
1031                           Output_section* output_section,
1032                           const elfcpp::Rel<32, false>& reloc,
1033                           unsigned int r_type,
1034                           Symbol* gsym)
1035 {
1036   switch (r_type)
1037     {
1038     case elfcpp::R_386_NONE:
1039     case elfcpp::R_386_GNU_VTINHERIT:
1040     case elfcpp::R_386_GNU_VTENTRY:
1041       break;
1042
1043     case elfcpp::R_386_32:
1044     case elfcpp::R_386_16:
1045     case elfcpp::R_386_8:
1046       {
1047         // Make a PLT entry if necessary.
1048         if (gsym->needs_plt_entry())
1049           {
1050             target->make_plt_entry(symtab, layout, gsym);
1051             // Since this is not a PC-relative relocation, we may be
1052             // taking the address of a function. In that case we need to
1053             // set the entry in the dynamic symbol table to the address of
1054             // the PLT entry.
1055             if (gsym->is_from_dynobj())
1056               gsym->set_needs_dynsym_value();
1057           }
1058         // Make a dynamic relocation if necessary.
1059         if (gsym->needs_dynamic_reloc(true, false))
1060           {
1061             if (target->may_need_copy_reloc(gsym))
1062               {
1063                 target->copy_reloc(&options, symtab, layout, object,
1064                                    data_shndx, output_section, gsym, reloc);
1065               }
1066             else if (r_type == elfcpp::R_386_32
1067                      && gsym->can_use_relative_reloc(false))
1068               {
1069                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1070                 rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
1071                                    output_section, data_shndx,
1072                                    reloc.get_r_offset());
1073               }
1074             else
1075               {
1076                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1077                 rel_dyn->add_global(gsym, r_type, output_section, object,
1078                                     data_shndx, reloc.get_r_offset());
1079               }
1080           }
1081       }
1082       break;
1083
1084     case elfcpp::R_386_PC32:
1085     case elfcpp::R_386_PC16:
1086     case elfcpp::R_386_PC8:
1087       {
1088         // Make a PLT entry if necessary.
1089         if (gsym->needs_plt_entry())
1090           target->make_plt_entry(symtab, layout, gsym);
1091         // Make a dynamic relocation if necessary.
1092         bool is_function_call = (gsym->type() == elfcpp::STT_FUNC);
1093         if (gsym->needs_dynamic_reloc(false, is_function_call))
1094           {
1095             if (target->may_need_copy_reloc(gsym))
1096               {
1097                 target->copy_reloc(&options, symtab, layout, object,
1098                                    data_shndx, output_section, gsym, reloc);
1099               }
1100             else
1101               {
1102                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1103                 rel_dyn->add_global(gsym, r_type, output_section, object,
1104                                     data_shndx, reloc.get_r_offset());
1105               }
1106           }
1107       }
1108       break;
1109
1110     case elfcpp::R_386_GOT32:
1111       {
1112         // The symbol requires a GOT entry.
1113         Output_data_got<32, false>* got = target->got_section(symtab, layout);
1114         if (got->add_global(gsym))
1115           {
1116             // If this symbol is not fully resolved, we need to add a
1117             // dynamic relocation for it.
1118             if (!gsym->final_value_is_known())
1119               {
1120                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1121                 if (gsym->is_from_dynobj()
1122                     || gsym->is_preemptible())
1123                   rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
1124                                       gsym->got_offset());
1125                 else
1126                   {
1127                     rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
1128                                        got, gsym->got_offset());
1129                     // Make sure we write the link-time value to the GOT.
1130                     gsym->set_needs_value_in_got();
1131                   }
1132               }
1133           }
1134       }
1135       break;
1136
1137     case elfcpp::R_386_PLT32:
1138       // If the symbol is fully resolved, this is just a PC32 reloc.
1139       // Otherwise we need a PLT entry.
1140       if (gsym->final_value_is_known())
1141         break;
1142       // If building a shared library, we can also skip the PLT entry
1143       // if the symbol is defined in the output file and is protected
1144       // or hidden.
1145       if (gsym->is_defined()
1146           && !gsym->is_from_dynobj()
1147           && !gsym->is_preemptible())
1148         break;
1149       target->make_plt_entry(symtab, layout, gsym);
1150       break;
1151
1152     case elfcpp::R_386_GOTOFF:
1153     case elfcpp::R_386_GOTPC:
1154       // We need a GOT section.
1155       target->got_section(symtab, layout);
1156       break;
1157
1158       // These are relocations which should only be seen by the
1159       // dynamic linker, and should never be seen here.
1160     case elfcpp::R_386_COPY:
1161     case elfcpp::R_386_GLOB_DAT:
1162     case elfcpp::R_386_JUMP_SLOT:
1163     case elfcpp::R_386_RELATIVE:
1164     case elfcpp::R_386_TLS_TPOFF:
1165     case elfcpp::R_386_TLS_DTPMOD32:
1166     case elfcpp::R_386_TLS_DTPOFF32:
1167     case elfcpp::R_386_TLS_TPOFF32:
1168     case elfcpp::R_386_TLS_DESC:
1169       gold_error(_("%s: unexpected reloc %u in object file"),
1170                  object->name().c_str(), r_type);
1171       break;
1172
1173       // These are initial tls relocs, which are expected when
1174       // linking.
1175     case elfcpp::R_386_TLS_GD:            // Global-dynamic
1176     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
1177     case elfcpp::R_386_TLS_DESC_CALL:
1178     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
1179     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
1180     case elfcpp::R_386_TLS_IE:            // Initial-exec
1181     case elfcpp::R_386_TLS_IE_32:
1182     case elfcpp::R_386_TLS_GOTIE:
1183     case elfcpp::R_386_TLS_LE:            // Local-exec
1184     case elfcpp::R_386_TLS_LE_32:
1185       {
1186         const bool is_final = gsym->final_value_is_known();
1187         const tls::Tls_optimization optimized_type
1188             = Target_i386::optimize_tls_reloc(is_final, r_type);
1189         switch (r_type)
1190           {
1191           case elfcpp::R_386_TLS_GD:          // Global-dynamic
1192             if (optimized_type == tls::TLSOPT_NONE)
1193               {
1194                 // Create a pair of GOT entries for the module index and
1195                 // dtv-relative offset.
1196                 Output_data_got<32, false>* got
1197                     = target->got_section(symtab, layout);
1198                 if (got->add_global_tls(gsym, true))
1199                   {
1200                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1201                     unsigned int got_off = gsym->tls_got_offset(true);
1202                     rel_dyn->add_global(gsym, elfcpp::R_386_TLS_DTPMOD32,
1203                                         got, got_off);
1204                     rel_dyn->add_global(gsym, elfcpp::R_386_TLS_DTPOFF32,
1205                                         got, got_off + 4);
1206                   }
1207               }
1208             else if (optimized_type == tls::TLSOPT_TO_IE)
1209               {
1210                 // Create a GOT entry for the tp-relative offset.
1211                 Output_data_got<32, false>* got
1212                     = target->got_section(symtab, layout);
1213                 if (got->add_global(gsym))
1214                   {
1215                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1216                     unsigned int got_off = gsym->got_offset();
1217                     rel_dyn->add_global(gsym, elfcpp::R_386_TLS_TPOFF32,
1218                                         got, got_off);
1219                   }
1220               }
1221             else if (optimized_type != tls::TLSOPT_TO_LE)
1222               unsupported_reloc_global(object, r_type, gsym);
1223             break;
1224
1225           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (~oliva url)
1226           case elfcpp::R_386_TLS_DESC_CALL:
1227             unsupported_reloc_global(object, r_type, gsym);
1228             break;
1229
1230           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
1231             // FIXME: If not relaxing to LE, we need to generate a
1232             // DTPMOD32 reloc.
1233             if (optimized_type == tls::TLSOPT_NONE)
1234               {
1235                 // Create a GOT entry for the module index.
1236                 Output_data_got<32, false>* got
1237                     = target->got_section(symtab, layout);
1238                 if (got->add_global_tls(gsym, false))
1239                   {
1240                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1241                     unsigned int got_off = gsym->tls_got_offset(false);
1242                     rel_dyn->add_global(gsym, elfcpp::R_386_TLS_DTPMOD32,
1243                                         got, got_off);
1244                   }
1245               }
1246             else if (optimized_type != tls::TLSOPT_TO_LE)
1247               unsupported_reloc_global(object, r_type, gsym);
1248             break;
1249
1250           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
1251             break;
1252
1253           case elfcpp::R_386_TLS_IE:          // Initial-exec
1254           case elfcpp::R_386_TLS_IE_32:
1255           case elfcpp::R_386_TLS_GOTIE:
1256             if (optimized_type == tls::TLSOPT_NONE)
1257               {
1258                 // Create a GOT entry for the tp-relative offset.
1259                 Output_data_got<32, false>* got
1260                     = target->got_section(symtab, layout);
1261                 if (got->add_global(gsym))
1262                   {
1263                     unsigned int dyn_r_type
1264                       = (r_type == elfcpp::R_386_TLS_IE_32
1265                          ? elfcpp::R_386_TLS_TPOFF32
1266                          : elfcpp::R_386_TLS_TPOFF);
1267                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1268                     unsigned int got_off = gsym->got_offset();
1269                     rel_dyn->add_global(gsym, dyn_r_type, got, got_off);
1270                   }
1271               }
1272             else if (optimized_type != tls::TLSOPT_TO_LE)
1273               unsupported_reloc_global(object, r_type, gsym);
1274             break;
1275
1276           case elfcpp::R_386_TLS_LE:          // Local-exec
1277           case elfcpp::R_386_TLS_LE_32:
1278             if (parameters->output_is_shared())
1279               unsupported_reloc_global(object, r_type, gsym);
1280             break;
1281
1282           default:
1283             gold_unreachable();
1284           }
1285       }
1286       break;
1287
1288     case elfcpp::R_386_32PLT:
1289     case elfcpp::R_386_TLS_GD_32:
1290     case elfcpp::R_386_TLS_GD_PUSH:
1291     case elfcpp::R_386_TLS_GD_CALL:
1292     case elfcpp::R_386_TLS_GD_POP:
1293     case elfcpp::R_386_TLS_LDM_32:
1294     case elfcpp::R_386_TLS_LDM_PUSH:
1295     case elfcpp::R_386_TLS_LDM_CALL:
1296     case elfcpp::R_386_TLS_LDM_POP:
1297     case elfcpp::R_386_USED_BY_INTEL_200:
1298     default:
1299       unsupported_reloc_global(object, r_type, gsym);
1300       break;
1301     }
1302 }
1303
1304 // Scan relocations for a section.
1305
1306 void
1307 Target_i386::scan_relocs(const General_options& options,
1308                          Symbol_table* symtab,
1309                          Layout* layout,
1310                          Sized_relobj<32, false>* object,
1311                          unsigned int data_shndx,
1312                          unsigned int sh_type,
1313                          const unsigned char* prelocs,
1314                          size_t reloc_count,
1315                          Output_section* output_section,
1316                          bool needs_special_offset_handling,
1317                          size_t local_symbol_count,
1318                          const unsigned char* plocal_symbols)
1319 {
1320   if (sh_type == elfcpp::SHT_RELA)
1321     {
1322       gold_error(_("%s: unsupported RELA reloc section"),
1323                  object->name().c_str());
1324       return;
1325     }
1326
1327   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1328                     Target_i386::Scan>(
1329     options,
1330     symtab,
1331     layout,
1332     this,
1333     object,
1334     data_shndx,
1335     prelocs,
1336     reloc_count,
1337     output_section,
1338     needs_special_offset_handling,
1339     local_symbol_count,
1340     plocal_symbols);
1341 }
1342
1343 // Finalize the sections.
1344
1345 void
1346 Target_i386::do_finalize_sections(Layout* layout)
1347 {
1348   // Fill in some more dynamic tags.
1349   Output_data_dynamic* const odyn = layout->dynamic_data();
1350   if (odyn != NULL)
1351     {
1352       if (this->got_plt_ != NULL)
1353         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1354
1355       if (this->plt_ != NULL)
1356         {
1357           const Output_data* od = this->plt_->rel_plt();
1358           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1359           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1360           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1361         }
1362
1363       if (this->rel_dyn_ != NULL)
1364         {
1365           const Output_data* od = this->rel_dyn_;
1366           odyn->add_section_address(elfcpp::DT_REL, od);
1367           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1368           odyn->add_constant(elfcpp::DT_RELENT,
1369                              elfcpp::Elf_sizes<32>::rel_size);
1370         }
1371
1372       if (!parameters->output_is_shared())
1373         {
1374           // The value of the DT_DEBUG tag is filled in by the dynamic
1375           // linker at run time, and used by the debugger.
1376           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1377         }
1378     }
1379
1380   // Emit any relocs we saved in an attempt to avoid generating COPY
1381   // relocs.
1382   if (this->copy_relocs_ == NULL)
1383     return;
1384   if (this->copy_relocs_->any_to_emit())
1385     {
1386       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1387       this->copy_relocs_->emit(rel_dyn);
1388     }
1389   delete this->copy_relocs_;
1390   this->copy_relocs_ = NULL;
1391 }
1392
1393 // Return whether a direct absolute static relocation needs to be applied.
1394 // In cases where Scan::local() or Scan::global() has created
1395 // a dynamic relocation other than R_386_RELATIVE, the addend
1396 // of the relocation is carried in the data, and we must not
1397 // apply the static relocation.
1398
1399 inline bool
1400 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1401                                                  bool is_absolute_ref,
1402                                                  bool is_function_call,
1403                                                  bool is_32bit)
1404 {
1405   // For local symbols, we will have created a non-RELATIVE dynamic
1406   // relocation only if (a) the output is position independent,
1407   // (b) the relocation is absolute (not pc- or segment-relative), and
1408   // (c) the relocation is not 32 bits wide.
1409   if (gsym == NULL)
1410     return !(parameters->output_is_position_independent()
1411              && is_absolute_ref
1412              && !is_32bit);
1413
1414   // For global symbols, we use the same helper routines used in the scan pass.
1415   return !(gsym->needs_dynamic_reloc(is_absolute_ref, is_function_call)
1416            && !gsym->can_use_relative_reloc(is_function_call));
1417 }
1418
1419 // Perform a relocation.
1420
1421 inline bool
1422 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1423                                 Target_i386* target,
1424                                 size_t relnum,
1425                                 const elfcpp::Rel<32, false>& rel,
1426                                 unsigned int r_type,
1427                                 const Sized_symbol<32>* gsym,
1428                                 const Symbol_value<32>* psymval,
1429                                 unsigned char* view,
1430                                 elfcpp::Elf_types<32>::Elf_Addr address,
1431                                 off_t view_size)
1432 {
1433   if (this->skip_call_tls_get_addr_)
1434     {
1435       if (r_type != elfcpp::R_386_PLT32
1436           || gsym == NULL
1437           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1438         gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1439                                _("missing expected TLS relocation"));
1440       else
1441         {
1442           this->skip_call_tls_get_addr_ = false;
1443           return false;
1444         }
1445     }
1446
1447   // Pick the value to use for symbols defined in shared objects.
1448   Symbol_value<32> symval;
1449   if (gsym != NULL
1450       && (gsym->is_from_dynobj()
1451           || (parameters->output_is_shared()
1452               && gsym->is_preemptible()))
1453       && gsym->has_plt_offset())
1454     {
1455       symval.set_output_value(target->plt_section()->address()
1456                               + gsym->plt_offset());
1457       psymval = &symval;
1458     }
1459
1460   const Sized_relobj<32, false>* object = relinfo->object;
1461
1462   // Get the GOT offset if needed.
1463   // The GOT pointer points to the end of the GOT section.
1464   // We need to subtract the size of the GOT section to get
1465   // the actual offset to use in the relocation.
1466   bool have_got_offset = false;
1467   unsigned int got_offset = 0;
1468   switch (r_type)
1469     {
1470     case elfcpp::R_386_GOT32:
1471       if (gsym != NULL)
1472         {
1473           gold_assert(gsym->has_got_offset());
1474           got_offset = gsym->got_offset() - target->got_size();
1475         }
1476       else
1477         {
1478           unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1479           gold_assert(object->local_has_got_offset(r_sym));
1480           got_offset = object->local_got_offset(r_sym) - target->got_size();
1481         }
1482       have_got_offset = true;
1483       break;
1484
1485     default:
1486       break;
1487     }
1488
1489   switch (r_type)
1490     {
1491     case elfcpp::R_386_NONE:
1492     case elfcpp::R_386_GNU_VTINHERIT:
1493     case elfcpp::R_386_GNU_VTENTRY:
1494       break;
1495
1496     case elfcpp::R_386_32:
1497       if (should_apply_static_reloc(gsym, true, false, true))
1498         Relocate_functions<32, false>::rel32(view, object, psymval);
1499       break;
1500
1501     case elfcpp::R_386_PC32:
1502       {
1503         bool is_function_call = (gsym != NULL
1504                                  && gsym->type() == elfcpp::STT_FUNC);
1505         if (should_apply_static_reloc(gsym, false, is_function_call, true))
1506           Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1507       }
1508       break;
1509
1510     case elfcpp::R_386_16:
1511       if (should_apply_static_reloc(gsym, true, false, false))
1512         Relocate_functions<32, false>::rel16(view, object, psymval);
1513       break;
1514
1515     case elfcpp::R_386_PC16:
1516       {
1517         bool is_function_call = (gsym != NULL
1518                                  && gsym->type() == elfcpp::STT_FUNC);
1519         if (should_apply_static_reloc(gsym, false, is_function_call, false))
1520           Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1521       }
1522       break;
1523
1524     case elfcpp::R_386_8:
1525       if (should_apply_static_reloc(gsym, true, false, false))
1526         Relocate_functions<32, false>::rel8(view, object, psymval);
1527       break;
1528
1529     case elfcpp::R_386_PC8:
1530       {
1531         bool is_function_call = (gsym != NULL
1532                                  && gsym->type() == elfcpp::STT_FUNC);
1533         if (should_apply_static_reloc(gsym, false, is_function_call, false))
1534           Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1535       }
1536       break;
1537
1538     case elfcpp::R_386_PLT32:
1539       gold_assert(gsym == NULL
1540                   || gsym->has_plt_offset()
1541                   || gsym->final_value_is_known());
1542       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1543       break;
1544
1545     case elfcpp::R_386_GOT32:
1546       gold_assert(have_got_offset);
1547       Relocate_functions<32, false>::rel32(view, got_offset);
1548       break;
1549
1550     case elfcpp::R_386_GOTOFF:
1551       {
1552         elfcpp::Elf_types<32>::Elf_Addr value;
1553         value = (psymval->value(object, 0)
1554                  - target->got_plt_section()->address());
1555         Relocate_functions<32, false>::rel32(view, value);
1556       }
1557       break;
1558
1559     case elfcpp::R_386_GOTPC:
1560       {
1561         elfcpp::Elf_types<32>::Elf_Addr value;
1562         value = target->got_plt_section()->address();
1563         Relocate_functions<32, false>::pcrel32(view, value, address);
1564       }
1565       break;
1566
1567     case elfcpp::R_386_COPY:
1568     case elfcpp::R_386_GLOB_DAT:
1569     case elfcpp::R_386_JUMP_SLOT:
1570     case elfcpp::R_386_RELATIVE:
1571       // These are outstanding tls relocs, which are unexpected when
1572       // linking.
1573     case elfcpp::R_386_TLS_TPOFF:
1574     case elfcpp::R_386_TLS_DTPMOD32:
1575     case elfcpp::R_386_TLS_DTPOFF32:
1576     case elfcpp::R_386_TLS_TPOFF32:
1577     case elfcpp::R_386_TLS_DESC:
1578       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1579                              _("unexpected reloc %u in object file"),
1580                              r_type);
1581       break;
1582
1583       // These are initial tls relocs, which are expected when
1584       // linking.
1585     case elfcpp::R_386_TLS_GD:             // Global-dynamic
1586     case elfcpp::R_386_TLS_GOTDESC:        // Global-dynamic (from ~oliva url)
1587     case elfcpp::R_386_TLS_DESC_CALL:
1588     case elfcpp::R_386_TLS_LDM:            // Local-dynamic
1589     case elfcpp::R_386_TLS_LDO_32:         // Alternate local-dynamic
1590     case elfcpp::R_386_TLS_IE:             // Initial-exec
1591     case elfcpp::R_386_TLS_IE_32:
1592     case elfcpp::R_386_TLS_GOTIE:
1593     case elfcpp::R_386_TLS_LE:             // Local-exec
1594     case elfcpp::R_386_TLS_LE_32:
1595       this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1596                          view, address, view_size);
1597       break;
1598
1599     case elfcpp::R_386_32PLT:
1600     case elfcpp::R_386_TLS_GD_32:
1601     case elfcpp::R_386_TLS_GD_PUSH:
1602     case elfcpp::R_386_TLS_GD_CALL:
1603     case elfcpp::R_386_TLS_GD_POP:
1604     case elfcpp::R_386_TLS_LDM_32:
1605     case elfcpp::R_386_TLS_LDM_PUSH:
1606     case elfcpp::R_386_TLS_LDM_CALL:
1607     case elfcpp::R_386_TLS_LDM_POP:
1608     case elfcpp::R_386_USED_BY_INTEL_200:
1609     default:
1610       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1611                              _("unsupported reloc %u"),
1612                              r_type);
1613       break;
1614     }
1615
1616   return true;
1617 }
1618
1619 // Perform a TLS relocation.
1620
1621 inline void
1622 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1623                                     Target_i386* target,
1624                                     size_t relnum,
1625                                     const elfcpp::Rel<32, false>& rel,
1626                                     unsigned int r_type,
1627                                     const Sized_symbol<32>* gsym,
1628                                     const Symbol_value<32>* psymval,
1629                                     unsigned char* view,
1630                                     elfcpp::Elf_types<32>::Elf_Addr,
1631                                     off_t view_size)
1632 {
1633   Output_segment* tls_segment = relinfo->layout->tls_segment();
1634
1635   const Sized_relobj<32, false>* object = relinfo->object;
1636
1637   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1638
1639   const bool is_final = (gsym == NULL
1640                          ? !parameters->output_is_position_independent()
1641                          : gsym->final_value_is_known());
1642   const tls::Tls_optimization optimized_type
1643       = Target_i386::optimize_tls_reloc(is_final, r_type);
1644   switch (r_type)
1645     {
1646     case elfcpp::R_386_TLS_GD:           // Global-dynamic
1647       if (optimized_type == tls::TLSOPT_TO_LE)
1648         {
1649           gold_assert(tls_segment != NULL);
1650           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1651                              rel, r_type, value, view,
1652                              view_size);
1653           break;
1654         }
1655       else
1656         {
1657           unsigned int got_offset;
1658           if (gsym != NULL)
1659             {
1660               gold_assert(gsym->has_tls_got_offset(true));
1661               got_offset = gsym->tls_got_offset(true) - target->got_size();
1662             }
1663           else
1664             {
1665               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1666               gold_assert(object->local_has_tls_got_offset(r_sym, true));
1667               got_offset = (object->local_tls_got_offset(r_sym, true)
1668                             - target->got_size());
1669             }
1670           if (optimized_type == tls::TLSOPT_TO_IE)
1671             {
1672               gold_assert(tls_segment != NULL);
1673               this->tls_gd_to_ie(relinfo, relnum, tls_segment,
1674                                  rel, r_type, got_offset, view,
1675                                  view_size);
1676               break;
1677             }
1678           else if (optimized_type == tls::TLSOPT_NONE)
1679             {
1680               // Relocate the field with the offset of the pair of GOT
1681               // entries.
1682               Relocate_functions<32, false>::rel32(view, got_offset);
1683               break;
1684             }
1685         }
1686       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1687                              _("unsupported reloc %u"),
1688                              r_type);
1689       break;
1690
1691     case elfcpp::R_386_TLS_GOTDESC:      // Global-dynamic (from ~oliva url)
1692     case elfcpp::R_386_TLS_DESC_CALL:
1693       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1694                              _("unsupported reloc %u"),
1695                              r_type);
1696       break;
1697
1698     case elfcpp::R_386_TLS_LDM:          // Local-dynamic
1699       if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1700         {
1701           gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1702                                  _("both SUN and GNU model "
1703                                    "TLS relocations"));
1704           break;
1705         }
1706       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1707       if (optimized_type == tls::TLSOPT_TO_LE)
1708         {
1709           gold_assert(tls_segment != NULL);
1710           this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1711                              value, view, view_size);
1712           break;
1713         }
1714       else if (optimized_type == tls::TLSOPT_NONE)
1715         {
1716           // Relocate the field with the offset of the GOT entry for
1717           // the module index.
1718           unsigned int got_offset;
1719           if (gsym != NULL)
1720             {
1721               gold_assert(gsym->has_tls_got_offset(false));
1722               got_offset = gsym->tls_got_offset(false) - target->got_size();
1723             }
1724           else
1725             {
1726               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1727               gold_assert(object->local_has_tls_got_offset(r_sym, false));
1728               got_offset = (object->local_tls_got_offset(r_sym, false)
1729                             - target->got_size());
1730             }
1731           Relocate_functions<32, false>::rel32(view, got_offset);
1732           break;
1733         }
1734       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1735                              _("unsupported reloc %u"),
1736                              r_type);
1737       break;
1738
1739     case elfcpp::R_386_TLS_LDO_32:       // Alternate local-dynamic
1740       // This reloc can appear in debugging sections, in which case we
1741       // won't see the TLS_LDM reloc.  The local_dynamic_type field
1742       // tells us this.
1743       gold_assert(tls_segment != NULL);
1744       if (optimized_type != tls::TLSOPT_TO_LE
1745           || this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
1746         value = value - tls_segment->vaddr();
1747       else if (this->local_dynamic_type_ == LOCAL_DYNAMIC_GNU)
1748         value = value - (tls_segment->vaddr() + tls_segment->memsz());
1749       else
1750         value = tls_segment->vaddr() + tls_segment->memsz() - value;
1751       Relocate_functions<32, false>::rel32(view, value);
1752       break;
1753
1754     case elfcpp::R_386_TLS_IE:           // Initial-exec
1755     case elfcpp::R_386_TLS_GOTIE:
1756     case elfcpp::R_386_TLS_IE_32:
1757       if (optimized_type == tls::TLSOPT_TO_LE)
1758         {
1759           gold_assert(tls_segment != NULL);
1760           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1761                                               rel, r_type, value, view,
1762                                               view_size);
1763           break;
1764         }
1765       else if (optimized_type == tls::TLSOPT_NONE)
1766         {
1767           // Relocate the field with the offset of the GOT entry for
1768           // the tp-relative offset of the symbol.
1769           unsigned int got_offset;
1770           if (gsym != NULL)
1771             {
1772               gold_assert(gsym->has_got_offset());
1773               got_offset = gsym->got_offset();
1774             }
1775           else
1776             {
1777               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1778               gold_assert(object->local_has_got_offset(r_sym));
1779               got_offset = object->local_got_offset(r_sym);
1780             }
1781           // For the R_386_TLS_IE relocation, we need to apply the
1782           // absolute address of the GOT entry.
1783           if (r_type == elfcpp::R_386_TLS_IE)
1784             got_offset += target->got_plt_section()->address();
1785           // All GOT offsets are relative to the end of the GOT.
1786           got_offset -= target->got_size();
1787           Relocate_functions<32, false>::rel32(view, got_offset);
1788           break;
1789         }
1790       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1791                              _("unsupported reloc %u"),
1792                              r_type);
1793       break;
1794
1795     case elfcpp::R_386_TLS_LE:           // Local-exec
1796       gold_assert(tls_segment != NULL);
1797       value = value - (tls_segment->vaddr() + tls_segment->memsz());
1798       Relocate_functions<32, false>::rel32(view, value);
1799       break;
1800
1801     case elfcpp::R_386_TLS_LE_32:
1802       gold_assert(tls_segment != NULL);
1803       value = tls_segment->vaddr() + tls_segment->memsz() - value;
1804       Relocate_functions<32, false>::rel32(view, value);
1805       break;
1806     }
1807 }
1808
1809 // Do a relocation in which we convert a TLS General-Dynamic to a
1810 // Local-Exec.
1811
1812 inline void
1813 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1814                                     size_t relnum,
1815                                     Output_segment* tls_segment,
1816                                     const elfcpp::Rel<32, false>& rel,
1817                                     unsigned int,
1818                                     elfcpp::Elf_types<32>::Elf_Addr value,
1819                                     unsigned char* view,
1820                                     off_t view_size)
1821 {
1822   // leal foo(,%reg,1),%eax; call ___tls_get_addr
1823   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1824   // leal foo(%reg),%eax; call ___tls_get_addr
1825   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1826
1827   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1828   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1829
1830   unsigned char op1 = view[-1];
1831   unsigned char op2 = view[-2];
1832
1833   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1834                  op2 == 0x8d || op2 == 0x04);
1835   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1836
1837   int roff = 5;
1838
1839   if (op2 == 0x04)
1840     {
1841       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1842       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1843       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1844                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1845       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1846     }
1847   else
1848     {
1849       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1850                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1851       if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1852           && view[9] == 0x90)
1853         {
1854           // There is a trailing nop.  Use the size byte subl.
1855           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1856           roff = 6;
1857         }
1858       else
1859         {
1860           // Use the five byte subl.
1861           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1862         }
1863     }
1864
1865   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1866   Relocate_functions<32, false>::rel32(view + roff, value);
1867
1868   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1869   // We can skip it.
1870   this->skip_call_tls_get_addr_ = true;
1871 }
1872
1873 // Do a relocation in which we convert a TLS General-Dynamic to a
1874 // Initial-Exec.
1875
1876 inline void
1877 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
1878                                     size_t relnum,
1879                                     Output_segment* tls_segment,
1880                                     const elfcpp::Rel<32, false>& rel,
1881                                     unsigned int,
1882                                     elfcpp::Elf_types<32>::Elf_Addr value,
1883                                     unsigned char* view,
1884                                     off_t view_size)
1885 {
1886   // leal foo(,%ebx,1),%eax; call ___tls_get_addr
1887   //  ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
1888
1889   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1890   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1891
1892   unsigned char op1 = view[-1];
1893   unsigned char op2 = view[-2];
1894
1895   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1896                  op2 == 0x8d || op2 == 0x04);
1897   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1898
1899   int roff = 5;
1900
1901   // FIXME: For now, support only one form.
1902   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1903                  op1 == 0x8d && op2 == 0x04);
1904
1905   if (op2 == 0x04)
1906     {
1907       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1908       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1909       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1910                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1911       memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
1912     }
1913   else
1914     {
1915       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1916                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1917       if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1918           && view[9] == 0x90)
1919         {
1920           // FIXME: This is not the right instruction sequence.
1921           // There is a trailing nop.  Use the size byte subl.
1922           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1923           roff = 6;
1924         }
1925       else
1926         {
1927           // FIXME: This is not the right instruction sequence.
1928           // Use the five byte subl.
1929           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1930         }
1931     }
1932
1933   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1934   Relocate_functions<32, false>::rel32(view + roff, value);
1935
1936   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1937   // We can skip it.
1938   this->skip_call_tls_get_addr_ = true;
1939 }
1940
1941 // Do a relocation in which we convert a TLS Local-Dynamic to a
1942 // Local-Exec.
1943
1944 inline void
1945 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
1946                                     size_t relnum,
1947                                     Output_segment*,
1948                                     const elfcpp::Rel<32, false>& rel,
1949                                     unsigned int,
1950                                     elfcpp::Elf_types<32>::Elf_Addr,
1951                                     unsigned char* view,
1952                                     off_t view_size)
1953 {
1954   // leal foo(%reg), %eax; call ___tls_get_addr
1955   // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1956
1957   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1958   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1959
1960   // FIXME: Does this test really always pass?
1961   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1962                  view[-2] == 0x8d && view[-1] == 0x83);
1963
1964   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1965
1966   memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1967
1968   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1969   // We can skip it.
1970   this->skip_call_tls_get_addr_ = true;
1971 }
1972
1973 // Do a relocation in which we convert a TLS Initial-Exec to a
1974 // Local-Exec.
1975
1976 inline void
1977 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1978                                     size_t relnum,
1979                                     Output_segment* tls_segment,
1980                                     const elfcpp::Rel<32, false>& rel,
1981                                     unsigned int r_type,
1982                                     elfcpp::Elf_types<32>::Elf_Addr value,
1983                                     unsigned char* view,
1984                                     off_t view_size)
1985 {
1986   // We have to actually change the instructions, which means that we
1987   // need to examine the opcodes to figure out which instruction we
1988   // are looking at.
1989   if (r_type == elfcpp::R_386_TLS_IE)
1990     {
1991       // movl %gs:XX,%eax  ==>  movl $YY,%eax
1992       // movl %gs:XX,%reg  ==>  movl $YY,%reg
1993       // addl %gs:XX,%reg  ==>  addl $YY,%reg
1994       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
1995       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1996
1997       unsigned char op1 = view[-1];
1998       if (op1 == 0xa1)
1999         {
2000           // movl XX,%eax  ==>  movl $YY,%eax
2001           view[-1] = 0xb8;
2002         }
2003       else
2004         {
2005           tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2006
2007           unsigned char op2 = view[-2];
2008           if (op2 == 0x8b)
2009             {
2010               // movl XX,%reg  ==>  movl $YY,%reg
2011               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2012                              (op1 & 0xc7) == 0x05);
2013               view[-2] = 0xc7;
2014               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2015             }
2016           else if (op2 == 0x03)
2017             {
2018               // addl XX,%reg  ==>  addl $YY,%reg
2019               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2020                              (op1 & 0xc7) == 0x05);
2021               view[-2] = 0x81;
2022               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2023             }
2024           else
2025             tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2026         }
2027     }
2028   else
2029     {
2030       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2031       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2032       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2033       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2034       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2035
2036       unsigned char op1 = view[-1];
2037       unsigned char op2 = view[-2];
2038       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2039                      (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2040       if (op2 == 0x8b)
2041         {
2042           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2043           view[-2] = 0xc7;
2044           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2045         }
2046       else if (op2 == 0x2b)
2047         {
2048           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2049           view[-2] = 0x81;
2050           view[-1] = 0xe8 | ((op1 >> 3) & 7);
2051         }
2052       else if (op2 == 0x03)
2053         {
2054           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2055           view[-2] = 0x81;
2056           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2057         }
2058       else
2059         tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2060     }
2061
2062   value = tls_segment->vaddr() + tls_segment->memsz() - value;
2063   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2064     value = - value;
2065
2066   Relocate_functions<32, false>::rel32(view, value);
2067 }
2068
2069 // Relocate section data.
2070
2071 void
2072 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2073                               unsigned int sh_type,
2074                               const unsigned char* prelocs,
2075                               size_t reloc_count,
2076                               Output_section* output_section,
2077                               bool needs_special_offset_handling,
2078                               unsigned char* view,
2079                               elfcpp::Elf_types<32>::Elf_Addr address,
2080                               off_t view_size)
2081 {
2082   gold_assert(sh_type == elfcpp::SHT_REL);
2083
2084   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2085                          Target_i386::Relocate>(
2086     relinfo,
2087     this,
2088     prelocs,
2089     reloc_count,
2090     output_section,
2091     needs_special_offset_handling,
2092     view,
2093     address,
2094     view_size);
2095 }
2096
2097 // Return the value to use for a dynamic which requires special
2098 // treatment.  This is how we support equality comparisons of function
2099 // pointers across shared library boundaries, as described in the
2100 // processor specific ABI supplement.
2101
2102 uint64_t
2103 Target_i386::do_dynsym_value(const Symbol* gsym) const
2104 {
2105   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2106   return this->plt_section()->address() + gsym->plt_offset();
2107 }
2108
2109 // Return a string used to fill a code section with nops to take up
2110 // the specified length.
2111
2112 std::string
2113 Target_i386::do_code_fill(off_t length)
2114 {
2115   if (length >= 16)
2116     {
2117       // Build a jmp instruction to skip over the bytes.
2118       unsigned char jmp[5];
2119       jmp[0] = 0xe9;
2120       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2121       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2122               + std::string(length - 5, '\0'));
2123     }
2124
2125   // Nop sequences of various lengths.
2126   const char nop1[1] = { 0x90 };                   // nop
2127   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2128   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2129   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2130   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2131                          0x00 };                   // leal 0(%esi,1),%esi
2132   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2133                          0x00, 0x00 };
2134   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2135                          0x00, 0x00, 0x00 };
2136   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2137                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2138   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2139                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2140                          0x00 };
2141   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2142                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2143                            0x00, 0x00 };
2144   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2145                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2146                            0x00, 0x00, 0x00 };
2147   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2148                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2149                            0x00, 0x00, 0x00, 0x00 };
2150   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2151                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2152                            0x27, 0x00, 0x00, 0x00,
2153                            0x00 };
2154   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2155                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2156                            0xbc, 0x27, 0x00, 0x00,
2157                            0x00, 0x00 };
2158   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2159                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2160                            0x90, 0x90, 0x90, 0x90,
2161                            0x90, 0x90, 0x90 };
2162
2163   const char* nops[16] = {
2164     NULL,
2165     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2166     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2167   };
2168
2169   return std::string(nops[length], length);
2170 }
2171
2172 // The selector for i386 object files.
2173
2174 class Target_selector_i386 : public Target_selector
2175 {
2176 public:
2177   Target_selector_i386()
2178     : Target_selector(elfcpp::EM_386, 32, false)
2179   { }
2180
2181   Target*
2182   recognize(int machine, int osabi, int abiversion);
2183
2184  private:
2185   Target_i386* target_;
2186 };
2187
2188 // Recognize an i386 object file when we already know that the machine
2189 // number is EM_386.
2190
2191 Target*
2192 Target_selector_i386::recognize(int, int, int)
2193 {
2194   if (this->target_ == NULL)
2195     this->target_ = new Target_i386();
2196   return this->target_;
2197 }
2198
2199 Target_selector_i386 target_selector_i386;
2200
2201 } // End anonymous namespace.