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
  39 namespace
  40 {
  41
  42 using namespace gold;
  43
  44 class Output_data_plt_i386;
  45
  46 // The i386 target class.
  47
  48 class Target_i386 : public Sized_target<32, false>
  49 {
  50  public:
  51   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
  52
  53   Target_i386()
  54     : Sized_target<32, false>(&i386_info),
  55       got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
  56       copy_relocs_(NULL), dynbss_(NULL)
  57   { }
  58
  59   // Scan the relocations to look for symbol adjustments.
  60   void
  61   scan_relocs(const General_options& options,
  62               Symbol_table* symtab,
  63               Layout* layout,
  64               Sized_relobj<32, false>* object,
  65               unsigned int data_shndx,
  66               unsigned int sh_type,
  67               const unsigned char* prelocs,
  68               size_t reloc_count,
  69               size_t local_symbol_count,
  70               const unsigned char* plocal_symbols,
  71               Symbol** global_symbols);
  72
  73   // Finalize the sections.
  74   void
  75   do_finalize_sections(Layout*);
  76
  77   // Relocate a section.
  78   void
  79   relocate_section(const Relocate_info<32, false>*,
  80                    unsigned int sh_type,
  81                    const unsigned char* prelocs,
  82                    size_t reloc_count,
  83                    unsigned char* view,
  84                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  85                    off_t view_size);
  86
  87   // Return a string used to fill a code section with nops.
  88   std::string
  89   do_code_fill(off_t length);
  90
  91  private:
  92   // The class which scans relocations.
  93   struct Scan
  94   {
  95     inline void
  96     local(const General_options& options, Symbol_table* symtab,
  97           Layout* layout, Target_i386* target,
  98           Sized_relobj<32, false>* object,
  99           unsigned int data_shndx,
 100           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 101           const elfcpp::Sym<32, false>& lsym);
 102
 103     inline void
 104     global(const General_options& options, Symbol_table* symtab,
 105            Layout* layout, Target_i386* target,
 106            Sized_relobj<32, false>* object,
 107            unsigned int data_shndx,
 108            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 109            Symbol* gsym);
 110   };
 111
 112   // The class which implements relocation.
 113   class Relocate
 114   {
 115    public:
 116     Relocate()
 117       : skip_call_tls_get_addr_(false)
 118     { }
 119
 120     ~Relocate()
 121     {
 122       if (this->skip_call_tls_get_addr_)
 123         {
 124           // FIXME: This needs to specify the location somehow.
 125           fprintf(stderr, _("%s: missing expected TLS relocation\n"),
 126                   program_name);
 127           gold_exit(false);
 128         }
 129     }
 130
 131     // Do a relocation.  Return false if the caller should not issue
 132     // any warnings about this relocation.
 133     inline bool
 134     relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
 135              const elfcpp::Rel<32, false>&,
 136              unsigned int r_type, const Sized_symbol<32>*,
 137              const Symbol_value<32>*,
 138              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 139              off_t);
 140
 141    private:
 142     // Do a TLS relocation.
 143     inline void
 144     relocate_tls(const Relocate_info<32, false>*, size_t relnum,
 145                  const elfcpp::Rel<32, false>&,
 146                  unsigned int r_type, const Sized_symbol<32>*,
 147                  const Symbol_value<32>*,
 148                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
 149
 150     // Do a TLS Initial-Exec to Local-Exec transition.
 151     static inline void
 152     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 153                  Output_segment* tls_segment,
 154                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 155                  elfcpp::Elf_types<32>::Elf_Addr value,
 156                  unsigned char* view,
 157                  off_t view_size);
 158
 159     // Do a TLS Global-Dynamic to Local-Exec transition.
 160     inline void
 161     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 162                  Output_segment* tls_segment,
 163                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 164                  elfcpp::Elf_types<32>::Elf_Addr value,
 165                  unsigned char* view,
 166                  off_t view_size);
 167
 168     // Check the range for a TLS relocation.
 169     static inline void
 170     check_range(const Relocate_info<32, false>*, size_t relnum,
 171                 const elfcpp::Rel<32, false>&, off_t, off_t);
 172
 173     // Check the validity of a TLS relocation.  This is like assert.
 174     static inline void
 175     check_tls(const Relocate_info<32, false>*, size_t relnum,
 176               const elfcpp::Rel<32, false>&, bool);
 177
 178     // This is set if we should skip the next reloc, which should be a
 179     // PLT32 reloc against ___tls_get_addr.
 180     bool skip_call_tls_get_addr_;
 181   };
 182
 183   // Adjust TLS relocation type based on the options and whether this
 184   // is a local symbol.
 185   static unsigned int
 186   optimize_tls_reloc(bool is_final, int r_type);
 187
 188   // Get the GOT section, creating it if necessary.
 189   Output_data_got<32, false>*
 190   got_section(Symbol_table*, Layout*);
 191
 192   // Create a PLT entry for a global symbol.
 193   void
 194   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 195
 196   // Get the PLT section.
 197   Output_data_plt_i386*
 198   plt_section() const
 199   {
 200     gold_assert(this->plt_ != NULL);
 201     return this->plt_;
 202   }
 203
 204   // Get the dynamic reloc section, creating it if necessary.
 205   Reloc_section*
 206   rel_dyn_section(Layout*);
 207
 208   // Copy a relocation against a global symbol.
 209   void
 210   copy_reloc(const General_options*, Symbol_table*, Layout*,
 211              Sized_relobj<32, false>*, unsigned int,
 212              Symbol*, const elfcpp::Rel<32, false>&);
 213
 214   // Information about this specific target which we pass to the
 215   // general Target structure.
 216   static const Target::Target_info i386_info;
 217
 218   // The GOT section.
 219   Output_data_got<32, false>* got_;
 220   // The PLT section.
 221   Output_data_plt_i386* plt_;
 222   // The GOT PLT section.
 223   Output_data_space* got_plt_;
 224   // The dynamic reloc section.
 225   Reloc_section* rel_dyn_;
 226   // Relocs saved to avoid a COPY reloc.
 227   Copy_relocs<32, false>* copy_relocs_;
 228   // Space for variables copied with a COPY reloc.
 229   Output_data_space* dynbss_;
 230 };
 231
 232 const Target::Target_info Target_i386::i386_info =
 233 {
 234   32,                   // size
 235   false,                // is_big_endian
 236   elfcpp::EM_386,       // machine_code
 237   false,                // has_make_symbol
 238   false,                // has_resolve
 239   true,                 // has_code_fill
 240   "/usr/lib/libc.so.1", // dynamic_linker
 241   0x08048000,           // text_segment_address
 242   0x1000,               // abi_pagesize
 243   0x1000                // common_pagesize
 244 };
 245
 246 // Get the GOT section, creating it if necessary.
 247
 248 Output_data_got<32, false>*
 249 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 250 {
 251   if (this->got_ == NULL)
 252     {
 253       gold_assert(symtab != NULL && layout != NULL);
 254
 255       this->got_ = new Output_data_got<32, false>();
 256
 257       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 258                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 259                                       this->got_);
 260
 261       // The old GNU linker creates a .got.plt section.  We just
 262       // create another set of data in the .got section.  Note that we
 263       // always create a PLT if we create a GOT, although the PLT
 264       // might be empty.
 265       this->got_plt_ = new Output_data_space(4);
 266       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 267                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 268                                       this->got_plt_);
 269
 270       // The first three entries are reserved.
 271       this->got_plt_->set_space_size(3 * 4);
 272
 273       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 274       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 275                                     this->got_plt_,
 276                                     0, 0, elfcpp::STT_OBJECT,
 277                                     elfcpp::STB_LOCAL,
 278                                     elfcpp::STV_HIDDEN, 0,
 279                                     false, false);
 280     }
 281
 282   return this->got_;
 283 }
 284
 285 // Get the dynamic reloc section, creating it if necessary.
 286
 287 Target_i386::Reloc_section*
 288 Target_i386::rel_dyn_section(Layout* layout)
 289 {
 290   if (this->rel_dyn_ == NULL)
 291     {
 292       gold_assert(layout != NULL);
 293       this->rel_dyn_ = new Reloc_section();
 294       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 295                                       elfcpp::SHF_ALLOC, this->rel_dyn_);
 296     }
 297   return this->rel_dyn_;
 298 }
 299
 300 // A class to handle the PLT data.
 301
 302 class Output_data_plt_i386 : public Output_section_data
 303 {
 304  public:
 305   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 306
 307   Output_data_plt_i386(Layout*, Output_data_space*);
 308
 309   // Add an entry to the PLT.
 310   void
 311   add_entry(Symbol* gsym);
 312
 313   // Return the .rel.plt section data.
 314   const Reloc_section*
 315   rel_plt() const
 316   { return this->rel_; }
 317
 318  protected:
 319   void
 320   do_adjust_output_section(Output_section* os);
 321
 322  private:
 323   // The size of an entry in the PLT.
 324   static const int plt_entry_size = 16;
 325
 326   // The first entry in the PLT for an executable.
 327   static unsigned char exec_first_plt_entry[plt_entry_size];
 328
 329   // The first entry in the PLT for a shared object.
 330   static unsigned char dyn_first_plt_entry[plt_entry_size];
 331
 332   // Other entries in the PLT for an executable.
 333   static unsigned char exec_plt_entry[plt_entry_size];
 334
 335   // Other entries in the PLT for a shared object.
 336   static unsigned char dyn_plt_entry[plt_entry_size];
 337
 338   // Set the final size.
 339   void
 340   do_set_address(uint64_t, off_t)
 341   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 342
 343   // Write out the PLT data.
 344   void
 345   do_write(Output_file*);
 346
 347   // The reloc section.
 348   Reloc_section* rel_;
 349   // The .got.plt section.
 350   Output_data_space* got_plt_;
 351   // The number of PLT entries.
 352   unsigned int count_;
 353 };
 354
 355 // Create the PLT section.  The ordinary .got section is an argument,
 356 // since we need to refer to the start.  We also create our own .got
 357 // section just for PLT entries.
 358
 359 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 360                                            Output_data_space* got_plt)
 361   : Output_section_data(4), got_plt_(got_plt), count_(0)
 362 {
 363   this->rel_ = new Reloc_section();
 364   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 365                                   elfcpp::SHF_ALLOC, this->rel_);
 366 }
 367
 368 // For some reason
 369
 370 void
 371 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 372 {
 373   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 374   // linker, and so do we.
 375   os->set_entsize(4);
 376 }
 377
 378 // Add an entry to the PLT.
 379
 380 void
 381 Output_data_plt_i386::add_entry(Symbol* gsym)
 382 {
 383   gold_assert(!gsym->has_plt_offset());
 384
 385   // Note that when setting the PLT offset we skip the initial
 386   // reserved PLT entry.
 387   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 388
 389   ++this->count_;
 390
 391   off_t got_offset = this->got_plt_->data_size();
 392
 393   // Every PLT entry needs a GOT entry which points back to the PLT
 394   // entry (this will be changed by the dynamic linker, normally
 395   // lazily when the function is called).
 396   this->got_plt_->set_space_size(got_offset + 4);
 397
 398   // Every PLT entry needs a reloc.
 399   gsym->set_needs_dynsym_entry();
 400   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 401                          got_offset);
 402
 403   // Note that we don't need to save the symbol.  The contents of the
 404   // PLT are independent of which symbols are used.  The symbols only
 405   // appear in the relocations.
 406 }
 407
 408 // The first entry in the PLT for an executable.
 409
 410 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 411 {
 412   0xff, 0x35,   // pushl contents of memory address
 413   0, 0, 0, 0,   // replaced with address of .got + 4
 414   0xff, 0x25,   // jmp indirect
 415   0, 0, 0, 0,   // replaced with address of .got + 8
 416   0, 0, 0, 0    // unused
 417 };
 418
 419 // The first entry in the PLT for a shared object.
 420
 421 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 422 {
 423   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 424   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 425   0, 0, 0, 0                    // unused
 426 };
 427
 428 // Subsequent entries in the PLT for an executable.
 429
 430 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 431 {
 432   0xff, 0x25,   // jmp indirect
 433   0, 0, 0, 0,   // replaced with address of symbol in .got
 434   0x68,         // pushl immediate
 435   0, 0, 0, 0,   // replaced with offset into relocation table
 436   0xe9,         // jmp relative
 437   0, 0, 0, 0    // replaced with offset to start of .plt
 438 };
 439
 440 // Subsequent entries in the PLT for a shared object.
 441
 442 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 443 {
 444   0xff, 0xa3,   // jmp *offset(%ebx)
 445   0, 0, 0, 0,   // replaced with offset of symbol in .got
 446   0x68,         // pushl immediate
 447   0, 0, 0, 0,   // replaced with offset into relocation table
 448   0xe9,         // jmp relative
 449   0, 0, 0, 0    // replaced with offset to start of .plt
 450 };
 451
 452 // Write out the PLT.  This uses the hand-coded instructions above,
 453 // and adjusts them as needed.  This is all specified by the i386 ELF
 454 // Processor Supplement.
 455
 456 void
 457 Output_data_plt_i386::do_write(Output_file* of)
 458 {
 459   const off_t offset = this->offset();
 460   const off_t oview_size = this->data_size();
 461   unsigned char* const oview = of->get_output_view(offset, oview_size);
 462
 463   const off_t got_file_offset = this->got_plt_->offset();
 464   const off_t got_size = this->got_plt_->data_size();
 465   unsigned char* const got_view = of->get_output_view(got_file_offset,
 466                                                       got_size);
 467
 468   unsigned char* pov = oview;
 469
 470   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 471   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 472
 473   if (parameters->output_is_shared())
 474     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 475   else
 476     {
 477       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 478       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 479       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 480     }
 481   pov += plt_entry_size;
 482
 483   unsigned char* got_pov = got_view;
 484
 485   memset(got_pov, 0, 12);
 486   got_pov += 12;
 487
 488   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 489
 490   unsigned int plt_offset = plt_entry_size;
 491   unsigned int plt_rel_offset = 0;
 492   unsigned int got_offset = 12;
 493   const unsigned int count = this->count_;
 494   for (unsigned int i = 0;
 495        i < count;
 496        ++i,
 497          pov += plt_entry_size,
 498          got_pov += 4,
 499          plt_offset += plt_entry_size,
 500          plt_rel_offset += rel_size,
 501          got_offset += 4)
 502     {
 503       // Set and adjust the PLT entry itself.
 504
 505       if (parameters->output_is_shared())
 506         {
 507           memcpy(pov, dyn_plt_entry, plt_entry_size);
 508           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 509         }
 510       else
 511         {
 512           memcpy(pov, exec_plt_entry, plt_entry_size);
 513           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 514                                                       (got_address
 515                                                        + got_offset));
 516         }
 517
 518       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 519       elfcpp::Swap<32, false>::writeval(pov + 12,
 520                                         - (plt_offset + plt_entry_size));
 521
 522       // Set the entry in the GOT.
 523       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 524     }
 525
 526   gold_assert(pov - oview == oview_size);
 527   gold_assert(got_pov - got_view == got_size);
 528
 529   of->write_output_view(offset, oview_size, oview);
 530   of->write_output_view(got_file_offset, got_size, got_view);
 531 }
 532
 533 // Create a PLT entry for a global symbol.
 534
 535 void
 536 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 537 {
 538   if (gsym->has_plt_offset())
 539     return;
 540
 541   if (this->plt_ == NULL)
 542     {
 543       // Create the GOT sections first.
 544       this->got_section(symtab, layout);
 545
 546       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 547       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 548                                       (elfcpp::SHF_ALLOC
 549                                        | elfcpp::SHF_EXECINSTR),
 550                                       this->plt_);
 551     }
 552
 553   this->plt_->add_entry(gsym);
 554 }
 555
 556 // Handle a relocation against a non-function symbol defined in a
 557 // dynamic object.  The traditional way to handle this is to generate
 558 // a COPY relocation to copy the variable at runtime from the shared
 559 // object into the executable's data segment.  However, this is
 560 // undesirable in general, as if the size of the object changes in the
 561 // dynamic object, the executable will no longer work correctly.  If
 562 // this relocation is in a writable section, then we can create a
 563 // dynamic reloc and the dynamic linker will resolve it to the correct
 564 // address at runtime.  However, we do not want do that if the
 565 // relocation is in a read-only section, as it would prevent the
 566 // readonly segment from being shared.  And if we have to eventually
 567 // generate a COPY reloc, then any dynamic relocations will be
 568 // useless.  So this means that if this is a writable section, we need
 569 // to save the relocation until we see whether we have to create a
 570 // COPY relocation for this symbol for any other relocation.
 571
 572 void
 573 Target_i386::copy_reloc(const General_options* options,
 574                         Symbol_table* symtab,
 575                         Layout* layout,
 576                         Sized_relobj<32, false>* object,
 577                         unsigned int data_shndx, Symbol* gsym,
 578                         const elfcpp::Rel<32, false>& rel)
 579 {
 580   Sized_symbol<32>* ssym;
 581   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
 582                                                         SELECT_SIZE(32));
 583
 584   if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
 585                                                data_shndx, ssym))
 586     {
 587       // So far we do not need a COPY reloc.  Save this relocation.
 588       // If it turns out that we never need a COPY reloc for this
 589       // symbol, then we will emit the relocation.
 590       if (this->copy_relocs_ == NULL)
 591         this->copy_relocs_ = new Copy_relocs<32, false>();
 592       this->copy_relocs_->save(ssym, object, data_shndx, rel);
 593     }
 594   else
 595     {
 596       // Allocate space for this symbol in the .bss section.
 597
 598       elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
 599
 600       // There is no defined way to determine the required alignment
 601       // of the symbol.  We pick the alignment based on the size.  We
 602       // set an arbitrary maximum of 256.
 603       unsigned int align;
 604       for (align = 1; align < 512; align <<= 1)
 605         if ((symsize & align) != 0)
 606           break;
 607
 608       if (this->dynbss_ == NULL)
 609         {
 610           this->dynbss_ = new Output_data_space(align);
 611           layout->add_output_section_data(".bss",
 612                                           elfcpp::SHT_NOBITS,
 613                                           (elfcpp::SHF_ALLOC
 614                                            | elfcpp::SHF_WRITE),
 615                                           this->dynbss_);
 616         }
 617
 618       Output_data_space* dynbss = this->dynbss_;
 619
 620       if (align > dynbss->addralign())
 621         dynbss->set_space_alignment(align);
 622
 623       off_t dynbss_size = dynbss->data_size();
 624       dynbss_size = align_address(dynbss_size, align);
 625       off_t offset = dynbss_size;
 626       dynbss->set_space_size(dynbss_size + symsize);
 627
 628       // Define the symbol in the .dynbss section.
 629       symtab->define_in_output_data(this, ssym->name(), ssym->version(),
 630                                     dynbss, offset, symsize, ssym->type(),
 631                                     ssym->binding(), ssym->visibility(),
 632                                     ssym->nonvis(), false, false);
 633
 634       // Add the COPY reloc.
 635       ssym->set_needs_dynsym_entry();
 636       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 637       rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
 638     }
 639 }
 640
 641 // Optimize the TLS relocation type based on what we know about the
 642 // symbol.  IS_FINAL is true if the final address of this symbol is
 643 // known at link time.
 644
 645 unsigned int
 646 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 647 {
 648   // If we are generating a shared library, then we can't do anything
 649   // in the linker.
 650   if (parameters->output_is_shared())
 651     return r_type;
 652
 653   switch (r_type)
 654     {
 655     case elfcpp::R_386_TLS_GD:
 656     case elfcpp::R_386_TLS_GOTDESC:
 657     case elfcpp::R_386_TLS_DESC_CALL:
 658       // These are Global-Dynamic which permits fully general TLS
 659       // access.  Since we know that we are generating an executable,
 660       // we can convert this to Initial-Exec.  If we also know that
 661       // this is a local symbol, we can further switch to Local-Exec.
 662       if (is_final)
 663         return elfcpp::R_386_TLS_LE_32;
 664       return elfcpp::R_386_TLS_IE_32;
 665
 666     case elfcpp::R_386_TLS_LDM:
 667       // This is Local-Dynamic, which refers to a local symbol in the
 668       // dynamic TLS block.  Since we know that we generating an
 669       // executable, we can switch to Local-Exec.
 670       return elfcpp::R_386_TLS_LE_32;
 671
 672     case elfcpp::R_386_TLS_LDO_32:
 673       // Another type of Local-Dynamic relocation.
 674       return elfcpp::R_386_TLS_LE;
 675
 676     case elfcpp::R_386_TLS_IE:
 677     case elfcpp::R_386_TLS_GOTIE:
 678     case elfcpp::R_386_TLS_IE_32:
 679       // These are Initial-Exec relocs which get the thread offset
 680       // from the GOT.  If we know that we are linking against the
 681       // local symbol, we can switch to Local-Exec, which links the
 682       // thread offset into the instruction.
 683       if (is_final)
 684         return elfcpp::R_386_TLS_LE_32;
 685       return r_type;
 686
 687     case elfcpp::R_386_TLS_LE:
 688     case elfcpp::R_386_TLS_LE_32:
 689       // When we already have Local-Exec, there is nothing further we
 690       // can do.
 691       return r_type;
 692
 693     default:
 694       gold_unreachable();
 695     }
 696 }
 697
 698 // Scan a relocation for a local symbol.
 699
 700 inline void
 701 Target_i386::Scan::local(const General_options&,
 702                          Symbol_table* symtab,
 703                          Layout* layout,
 704                          Target_i386* target,
 705                          Sized_relobj<32, false>* object,
 706                          unsigned int,
 707                          const elfcpp::Rel<32, false>&,
 708                          unsigned int r_type,
 709                          const elfcpp::Sym<32, false>&)
 710 {
 711   switch (r_type)
 712     {
 713     case elfcpp::R_386_NONE:
 714     case elfcpp::R_386_GNU_VTINHERIT:
 715     case elfcpp::R_386_GNU_VTENTRY:
 716       break;
 717
 718     case elfcpp::R_386_32:
 719     case elfcpp::R_386_16:
 720     case elfcpp::R_386_8:
 721       // FIXME: If we are generating a shared object we need to copy
 722       // this relocation into the object.
 723       gold_assert(!parameters->output_is_shared());
 724       break;
 725
 726     case elfcpp::R_386_PC32:
 727     case elfcpp::R_386_PC16:
 728     case elfcpp::R_386_PC8:
 729       break;
 730
 731     case elfcpp::R_386_GOTOFF:
 732     case elfcpp::R_386_GOTPC:
 733       // We need a GOT section.
 734       target->got_section(symtab, layout);
 735       break;
 736
 737     case elfcpp::R_386_COPY:
 738     case elfcpp::R_386_GLOB_DAT:
 739     case elfcpp::R_386_JUMP_SLOT:
 740     case elfcpp::R_386_RELATIVE:
 741     case elfcpp::R_386_TLS_TPOFF:
 742     case elfcpp::R_386_TLS_DTPMOD32:
 743     case elfcpp::R_386_TLS_DTPOFF32:
 744     case elfcpp::R_386_TLS_TPOFF32:
 745     case elfcpp::R_386_TLS_DESC:
 746       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 747               program_name, object->name().c_str(), r_type);
 748       gold_exit(false);
 749       break;
 750
 751     case elfcpp::R_386_TLS_IE:
 752     case elfcpp::R_386_TLS_GOTIE:
 753     case elfcpp::R_386_TLS_LE:
 754     case elfcpp::R_386_TLS_GD:
 755     case elfcpp::R_386_TLS_LDM:
 756     case elfcpp::R_386_TLS_LDO_32:
 757     case elfcpp::R_386_TLS_IE_32:
 758     case elfcpp::R_386_TLS_LE_32:
 759     case elfcpp::R_386_TLS_GOTDESC:
 760     case elfcpp::R_386_TLS_DESC_CALL:
 761       {
 762         bool output_is_shared = parameters->output_is_shared();
 763         r_type = Target_i386::optimize_tls_reloc(!output_is_shared,
 764                                                  r_type);
 765         switch (r_type)
 766           {
 767           case elfcpp::R_386_TLS_LE:
 768           case elfcpp::R_386_TLS_LE_32:
 769             // FIXME: If generating a shared object, we need to copy
 770             // this relocation into the object.
 771             gold_assert(!output_is_shared);
 772             break;
 773
 774           case elfcpp::R_386_TLS_IE:
 775           case elfcpp::R_386_TLS_GOTIE:
 776           case elfcpp::R_386_TLS_GD:
 777           case elfcpp::R_386_TLS_LDM:
 778           case elfcpp::R_386_TLS_LDO_32:
 779           case elfcpp::R_386_TLS_IE_32:
 780           case elfcpp::R_386_TLS_GOTDESC:
 781           case elfcpp::R_386_TLS_DESC_CALL:
 782             fprintf(stderr,
 783                     _("%s: %s: unsupported reloc %u against local symbol\n"),
 784                     program_name, object->name().c_str(), r_type);
 785             break;
 786           }
 787       }
 788       break;
 789
 790     case elfcpp::R_386_GOT32:
 791     case elfcpp::R_386_PLT32:
 792     case elfcpp::R_386_32PLT:
 793     case elfcpp::R_386_TLS_GD_32:
 794     case elfcpp::R_386_TLS_GD_PUSH:
 795     case elfcpp::R_386_TLS_GD_CALL:
 796     case elfcpp::R_386_TLS_GD_POP:
 797     case elfcpp::R_386_TLS_LDM_32:
 798     case elfcpp::R_386_TLS_LDM_PUSH:
 799     case elfcpp::R_386_TLS_LDM_CALL:
 800     case elfcpp::R_386_TLS_LDM_POP:
 801     case elfcpp::R_386_USED_BY_INTEL_200:
 802     default:
 803       fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"),
 804               program_name, object->name().c_str(), r_type);
 805       break;
 806     }
 807 }
 808
 809 // Scan a relocation for a global symbol.
 810
 811 inline void
 812 Target_i386::Scan::global(const General_options& options,
 813                           Symbol_table* symtab,
 814                           Layout* layout,
 815                           Target_i386* target,
 816                           Sized_relobj<32, false>* object,
 817                           unsigned int data_shndx,
 818                           const elfcpp::Rel<32, false>& reloc,
 819                           unsigned int r_type,
 820                           Symbol* gsym)
 821 {
 822   switch (r_type)
 823     {
 824     case elfcpp::R_386_NONE:
 825     case elfcpp::R_386_GNU_VTINHERIT:
 826     case elfcpp::R_386_GNU_VTENTRY:
 827       break;
 828
 829     case elfcpp::R_386_32:
 830     case elfcpp::R_386_PC32:
 831     case elfcpp::R_386_16:
 832     case elfcpp::R_386_PC16:
 833     case elfcpp::R_386_8:
 834     case elfcpp::R_386_PC8:
 835       // FIXME: If we are generating a shared object we may need to
 836       // copy this relocation into the object.  If this symbol is
 837       // defined in a shared object, we may need to copy this
 838       // relocation in order to avoid a COPY relocation.
 839       gold_assert(!parameters->output_is_shared());
 840
 841       if (gsym->is_from_dynobj())
 842         {
 843           // This symbol is defined in a dynamic object.  If it is a
 844           // function, we make a PLT entry.  Otherwise we need to
 845           // either generate a COPY reloc or copy this reloc.
 846           if (gsym->type() == elfcpp::STT_FUNC)
 847             target->make_plt_entry(symtab, layout, gsym);
 848           else
 849             target->copy_reloc(&options, symtab, layout, object, data_shndx,
 850                                gsym, reloc);
 851         }
 852
 853       break;
 854
 855     case elfcpp::R_386_GOT32:
 856       {
 857         // The symbol requires a GOT entry.
 858         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 859         if (got->add_global(gsym))
 860           {
 861             // If this symbol is not fully resolved, we need to add a
 862             // dynamic relocation for it.
 863             if (!gsym->final_value_is_known())
 864               {
 865                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 866                 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
 867                                     gsym->got_offset());
 868               }
 869           }
 870       }
 871       break;
 872
 873     case elfcpp::R_386_PLT32:
 874       // If the symbol is fully resolved, this is just a PC32 reloc.
 875       // Otherwise we need a PLT entry.
 876       if (gsym->final_value_is_known())
 877         break;
 878       target->make_plt_entry(symtab, layout, gsym);
 879       break;
 880
 881     case elfcpp::R_386_GOTOFF:
 882     case elfcpp::R_386_GOTPC:
 883       // We need a GOT section.
 884       target->got_section(symtab, layout);
 885       break;
 886
 887     case elfcpp::R_386_COPY:
 888     case elfcpp::R_386_GLOB_DAT:
 889     case elfcpp::R_386_JUMP_SLOT:
 890     case elfcpp::R_386_RELATIVE:
 891     case elfcpp::R_386_TLS_TPOFF:
 892     case elfcpp::R_386_TLS_DTPMOD32:
 893     case elfcpp::R_386_TLS_DTPOFF32:
 894     case elfcpp::R_386_TLS_TPOFF32:
 895     case elfcpp::R_386_TLS_DESC:
 896       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 897               program_name, object->name().c_str(), r_type);
 898       gold_exit(false);
 899       break;
 900
 901     case elfcpp::R_386_TLS_IE:
 902     case elfcpp::R_386_TLS_GOTIE:
 903     case elfcpp::R_386_TLS_LE:
 904     case elfcpp::R_386_TLS_GD:
 905     case elfcpp::R_386_TLS_LDM:
 906     case elfcpp::R_386_TLS_LDO_32:
 907     case elfcpp::R_386_TLS_IE_32:
 908     case elfcpp::R_386_TLS_LE_32:
 909     case elfcpp::R_386_TLS_GOTDESC:
 910     case elfcpp::R_386_TLS_DESC_CALL:
 911       {
 912         const bool is_final = gsym->final_value_is_known();
 913         r_type = Target_i386::optimize_tls_reloc(is_final, r_type);
 914         switch (r_type)
 915           {
 916           case elfcpp::R_386_TLS_LE:
 917           case elfcpp::R_386_TLS_LE_32:
 918             // FIXME: If generating a shared object, we need to copy
 919             // this relocation into the object.
 920             gold_assert(!parameters->output_is_shared());
 921             break;
 922
 923           case elfcpp::R_386_TLS_IE:
 924           case elfcpp::R_386_TLS_GOTIE:
 925           case elfcpp::R_386_TLS_GD:
 926           case elfcpp::R_386_TLS_LDM:
 927           case elfcpp::R_386_TLS_LDO_32:
 928           case elfcpp::R_386_TLS_IE_32:
 929           case elfcpp::R_386_TLS_GOTDESC:
 930           case elfcpp::R_386_TLS_DESC_CALL:
 931             fprintf(stderr,
 932                     _("%s: %s: unsupported reloc %u "
 933                       "against global symbol %s\n"),
 934                     program_name, object->name().c_str(), r_type,
 935                     gsym->name());
 936             break;
 937           }
 938       }
 939       break;
 940
 941     case elfcpp::R_386_32PLT:
 942     case elfcpp::R_386_TLS_GD_32:
 943     case elfcpp::R_386_TLS_GD_PUSH:
 944     case elfcpp::R_386_TLS_GD_CALL:
 945     case elfcpp::R_386_TLS_GD_POP:
 946     case elfcpp::R_386_TLS_LDM_32:
 947     case elfcpp::R_386_TLS_LDM_PUSH:
 948     case elfcpp::R_386_TLS_LDM_CALL:
 949     case elfcpp::R_386_TLS_LDM_POP:
 950     case elfcpp::R_386_USED_BY_INTEL_200:
 951     default:
 952       fprintf(stderr,
 953               _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 954               program_name, object->name().c_str(), r_type, gsym->name());
 955       break;
 956     }
 957 }
 958
 959 // Scan relocations for a section.
 960
 961 void
 962 Target_i386::scan_relocs(const General_options& options,
 963                          Symbol_table* symtab,
 964                          Layout* layout,
 965                          Sized_relobj<32, false>* object,
 966                          unsigned int data_shndx,
 967                          unsigned int sh_type,
 968                          const unsigned char* prelocs,
 969                          size_t reloc_count,
 970                          size_t local_symbol_count,
 971                          const unsigned char* plocal_symbols,
 972                          Symbol** global_symbols)
 973 {
 974   if (sh_type == elfcpp::SHT_RELA)
 975     {
 976       fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"),
 977               program_name, object->name().c_str());
 978       gold_exit(false);
 979     }
 980
 981   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
 982                     Target_i386::Scan>(
 983     options,
 984     symtab,
 985     layout,
 986     this,
 987     object,
 988     data_shndx,
 989     prelocs,
 990     reloc_count,
 991     local_symbol_count,
 992     plocal_symbols,
 993     global_symbols);
 994 }
 995
 996 // Finalize the sections.
 997
 998 void
 999 Target_i386::do_finalize_sections(Layout* layout)
1000 {
1001   // Fill in some more dynamic tags.
1002   Output_data_dynamic* const odyn = layout->dynamic_data();
1003   if (odyn != NULL)
1004     {
1005       if (this->got_plt_ != NULL)
1006         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1007
1008       if (this->plt_ != NULL)
1009         {
1010           const Output_data* od = this->plt_->rel_plt();
1011           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1012           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1013           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1014         }
1015
1016       if (this->rel_dyn_ != NULL)
1017         {
1018           const Output_data* od = this->rel_dyn_;
1019           odyn->add_section_address(elfcpp::DT_REL, od);
1020           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1021           odyn->add_constant(elfcpp::DT_RELENT,
1022                              elfcpp::Elf_sizes<32>::rel_size);
1023         }
1024
1025       if (!parameters->output_is_shared())
1026         {
1027           // The value of the DT_DEBUG tag is filled in by the dynamic
1028           // linker at run time, and used by the debugger.
1029           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1030         }
1031     }
1032
1033   // Emit any relocs we saved in an attempt to avoid generating COPY
1034   // relocs.
1035   if (this->copy_relocs_ == NULL)
1036     return;
1037   if (this->copy_relocs_->any_to_emit())
1038     {
1039       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1040       this->copy_relocs_->emit(rel_dyn);
1041     }
1042   delete this->copy_relocs_;
1043   this->copy_relocs_ = NULL;
1044 }
1045
1046 // Perform a relocation.
1047
1048 inline bool
1049 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1050                                 Target_i386* target,
1051                                 size_t relnum,
1052                                 const elfcpp::Rel<32, false>& rel,
1053                                 unsigned int r_type,
1054                                 const Sized_symbol<32>* gsym,
1055                                 const Symbol_value<32>* psymval,
1056                                 unsigned char* view,
1057                                 elfcpp::Elf_types<32>::Elf_Addr address,
1058                                 off_t view_size)
1059 {
1060   if (this->skip_call_tls_get_addr_)
1061     {
1062       if (r_type != elfcpp::R_386_PLT32
1063           || gsym == NULL
1064           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1065         {
1066           fprintf(stderr, _("%s: %s: missing expected TLS relocation\n"),
1067                   program_name,
1068                   relinfo->location(relnum, rel.get_r_offset()).c_str());
1069           gold_exit(false);
1070         }
1071
1072       this->skip_call_tls_get_addr_ = false;
1073
1074       return false;
1075     }
1076
1077   // Pick the value to use for symbols defined in shared objects.
1078   Symbol_value<32> symval;
1079   if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset())
1080     {
1081       symval.set_output_value(target->plt_section()->address()
1082                               + gsym->plt_offset());
1083       psymval = &symval;
1084     }
1085
1086   const Sized_relobj<32, false>* object = relinfo->object;
1087
1088   switch (r_type)
1089     {
1090     case elfcpp::R_386_NONE:
1091     case elfcpp::R_386_GNU_VTINHERIT:
1092     case elfcpp::R_386_GNU_VTENTRY:
1093       break;
1094
1095     case elfcpp::R_386_32:
1096       Relocate_functions<32, false>::rel32(view, object, psymval);
1097       break;
1098
1099     case elfcpp::R_386_PC32:
1100       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1101       break;
1102
1103     case elfcpp::R_386_16:
1104       Relocate_functions<32, false>::rel16(view, object, psymval);
1105       break;
1106
1107     case elfcpp::R_386_PC16:
1108       Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1109       break;
1110
1111     case elfcpp::R_386_8:
1112       Relocate_functions<32, false>::rel8(view, object, psymval);
1113       break;
1114
1115     case elfcpp::R_386_PC8:
1116       Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1117       break;
1118
1119     case elfcpp::R_386_PLT32:
1120       gold_assert(gsym->has_plt_offset()
1121                   || gsym->final_value_is_known());
1122       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1123       break;
1124
1125     case elfcpp::R_386_GOT32:
1126       // Local GOT offsets not yet supported.
1127       gold_assert(gsym);
1128       gold_assert(gsym->has_got_offset());
1129       Relocate_functions<32, false>::rel32(view, gsym->got_offset());
1130       break;
1131
1132     case elfcpp::R_386_GOTOFF:
1133       {
1134         elfcpp::Elf_types<32>::Elf_Addr value;
1135         value = (psymval->value(object, 0)
1136                  - target->got_section(NULL, NULL)->address());
1137         Relocate_functions<32, false>::rel32(view, value);
1138       }
1139       break;
1140
1141     case elfcpp::R_386_GOTPC:
1142       {
1143         elfcpp::Elf_types<32>::Elf_Addr value;
1144         value = target->got_section(NULL, NULL)->address();
1145         Relocate_functions<32, false>::pcrel32(view, value, address);
1146       }
1147       break;
1148
1149     case elfcpp::R_386_COPY:
1150     case elfcpp::R_386_GLOB_DAT:
1151     case elfcpp::R_386_JUMP_SLOT:
1152     case elfcpp::R_386_RELATIVE:
1153     case elfcpp::R_386_TLS_TPOFF:
1154     case elfcpp::R_386_TLS_DTPMOD32:
1155     case elfcpp::R_386_TLS_DTPOFF32:
1156     case elfcpp::R_386_TLS_TPOFF32:
1157     case elfcpp::R_386_TLS_DESC:
1158       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
1159               program_name,
1160               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1161               r_type);
1162       gold_exit(false);
1163       break;
1164
1165     case elfcpp::R_386_TLS_IE:
1166     case elfcpp::R_386_TLS_GOTIE:
1167     case elfcpp::R_386_TLS_LE:
1168     case elfcpp::R_386_TLS_GD:
1169     case elfcpp::R_386_TLS_LDM:
1170     case elfcpp::R_386_TLS_LDO_32:
1171     case elfcpp::R_386_TLS_IE_32:
1172     case elfcpp::R_386_TLS_LE_32:
1173     case elfcpp::R_386_TLS_GOTDESC:
1174     case elfcpp::R_386_TLS_DESC_CALL:
1175       this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1176                          address, view_size);
1177       break;
1178
1179     case elfcpp::R_386_32PLT:
1180     case elfcpp::R_386_TLS_GD_32:
1181     case elfcpp::R_386_TLS_GD_PUSH:
1182     case elfcpp::R_386_TLS_GD_CALL:
1183     case elfcpp::R_386_TLS_GD_POP:
1184     case elfcpp::R_386_TLS_LDM_32:
1185     case elfcpp::R_386_TLS_LDM_PUSH:
1186     case elfcpp::R_386_TLS_LDM_CALL:
1187     case elfcpp::R_386_TLS_LDM_POP:
1188     case elfcpp::R_386_USED_BY_INTEL_200:
1189     default:
1190       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1191               program_name,
1192               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1193               r_type);
1194       // gold_exit(false);
1195       break;
1196     }
1197
1198   return true;
1199 }
1200
1201 // Perform a TLS relocation.
1202
1203 inline void
1204 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1205                                     size_t relnum,
1206                                     const elfcpp::Rel<32, false>& rel,
1207                                     unsigned int r_type,
1208                                     const Sized_symbol<32>* gsym,
1209                                     const Symbol_value<32>* psymval,
1210                                     unsigned char* view,
1211                                     elfcpp::Elf_types<32>::Elf_Addr,
1212                                     off_t view_size)
1213 {
1214   Output_segment* tls_segment = relinfo->layout->tls_segment();
1215   if (tls_segment == NULL)
1216     {
1217       fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"),
1218               program_name,
1219               relinfo->location(relnum, rel.get_r_offset()).c_str());
1220       gold_exit(false);
1221     }
1222
1223   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1224
1225   const bool is_final = (gsym == NULL
1226                          ? !parameters->output_is_shared()
1227                          : gsym->final_value_is_known());
1228   const unsigned int opt_r_type =
1229     Target_i386::optimize_tls_reloc(is_final, r_type);
1230   switch (r_type)
1231     {
1232     case elfcpp::R_386_TLS_LE_32:
1233       value = tls_segment->vaddr() + tls_segment->memsz() - value;
1234       Relocate_functions<32, false>::rel32(view, value);
1235       break;
1236
1237     case elfcpp::R_386_TLS_LE:
1238       value = value - (tls_segment->vaddr() + tls_segment->memsz());
1239       Relocate_functions<32, false>::rel32(view, value);
1240       break;
1241
1242     case elfcpp::R_386_TLS_IE:
1243     case elfcpp::R_386_TLS_GOTIE:
1244     case elfcpp::R_386_TLS_IE_32:
1245       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1246         {
1247           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1248                                               rel, r_type, value, view,
1249                                               view_size);
1250           break;
1251         }
1252       fprintf(stderr, _("%s: %s: unsupported reloc type %u\n"),
1253               program_name,
1254               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1255               r_type);
1256       // gold_exit(false);
1257       break;
1258
1259     case elfcpp::R_386_TLS_GD:
1260       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1261         {
1262           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1263                              rel, r_type, value, view,
1264                              view_size);
1265           break;
1266         }
1267       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1268               program_name,
1269               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1270               r_type);
1271       // gold_exit(false);
1272       break;
1273
1274     case elfcpp::R_386_TLS_LDM:
1275     case elfcpp::R_386_TLS_LDO_32:
1276     case elfcpp::R_386_TLS_GOTDESC:
1277     case elfcpp::R_386_TLS_DESC_CALL:
1278       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1279               program_name,
1280               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1281               r_type);
1282       // gold_exit(false);
1283       break;
1284     }
1285 }
1286
1287 // Do a relocation in which we convert a TLS Initial-Exec to a
1288 // Local-Exec.
1289
1290 inline void
1291 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1292                                     size_t relnum,
1293                                     Output_segment* tls_segment,
1294                                     const elfcpp::Rel<32, false>& rel,
1295                                     unsigned int r_type,
1296                                     elfcpp::Elf_types<32>::Elf_Addr value,
1297                                     unsigned char* view,
1298                                     off_t view_size)
1299 {
1300   // We have to actually change the instructions, which means that we
1301   // need to examine the opcodes to figure out which instruction we
1302   // are looking at.
1303   if (r_type == elfcpp::R_386_TLS_IE)
1304     {
1305       // movl %gs:XX,%eax  ==>  movl $YY,%eax
1306       // movl %gs:XX,%reg  ==>  movl $YY,%reg
1307       // addl %gs:XX,%reg  ==>  addl $YY,%reg
1308       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -1);
1309       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1310
1311       unsigned char op1 = view[-1];
1312       if (op1 == 0xa1)
1313         {
1314           // movl XX,%eax  ==>  movl $YY,%eax
1315           view[-1] = 0xb8;
1316         }
1317       else
1318         {
1319           Target_i386::Relocate::check_range(relinfo, relnum, rel,
1320                                              view_size, -2);
1321
1322           unsigned char op2 = view[-2];
1323           if (op2 == 0x8b)
1324             {
1325               // movl XX,%reg  ==>  movl $YY,%reg
1326               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1327                                                (op1 & 0xc7) == 0x05);
1328               view[-2] = 0xc7;
1329               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1330             }
1331           else if (op2 == 0x03)
1332             {
1333               // addl XX,%reg  ==>  addl $YY,%reg
1334               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1335                                                (op1 & 0xc7) == 0x05);
1336               view[-2] = 0x81;
1337               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1338             }
1339           else
1340             Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1341         }
1342     }
1343   else
1344     {
1345       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1346       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1347       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1348       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1349       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1350
1351       unsigned char op1 = view[-1];
1352       unsigned char op2 = view[-2];
1353       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1354                                        (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1355       if (op2 == 0x8b)
1356         {
1357           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1358           view[-2] = 0xc7;
1359           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1360         }
1361       else if (op2 == 0x2b)
1362         {
1363           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1364           view[-2] = 0x81;
1365           view[-1] = 0xe8 | ((op1 >> 3) & 7);
1366         }
1367       else if (op2 == 0x03)
1368         {
1369           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1370           view[-2] = 0x81;
1371           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1372         }
1373       else
1374         Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1375     }
1376
1377   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1378   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1379     value = - value;
1380
1381   Relocate_functions<32, false>::rel32(view, value);
1382 }
1383
1384 // Do a relocation in which we convert a TLS Global-Dynamic to a
1385 // Local-Exec.
1386
1387 inline void
1388 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1389                                     size_t relnum,
1390                                     Output_segment* tls_segment,
1391                                     const elfcpp::Rel<32, false>& rel,
1392                                     unsigned int,
1393                                     elfcpp::Elf_types<32>::Elf_Addr value,
1394                                     unsigned char* view,
1395                                     off_t view_size)
1396 {
1397   // leal foo(,%reg,1),%eax; call ___tls_get_addr
1398   //  ==> movl %gs,0,%eax; subl $foo@tpoff,%eax
1399   // leal foo(%reg),%eax; call ___tls_get_addr
1400   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1401
1402   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1403   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 9);
1404
1405   unsigned char op1 = view[-1];
1406   unsigned char op2 = view[-2];
1407
1408   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1409                                    op2 == 0x8d || op2 == 0x04);
1410   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1411                                    view[4] == 0xe8);
1412
1413   int roff = 5;
1414
1415   if (op2 == 0x04)
1416     {
1417       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -3);
1418       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1419                                        view[-3] == 0x8d);
1420       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1421                                        ((op1 & 0xc7) == 0x05
1422                                         && op1 != (4 << 3)));
1423       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1424     }
1425   else
1426     {
1427       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1428                                        (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1429       if (rel.get_r_offset() + 9 < view_size && view[9] == 0x90)
1430         {
1431           // There is a trailing nop.  Use the size byte subl.
1432           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1433           roff = 6;
1434         }
1435       else
1436         {
1437           // Use the five byte subl.
1438           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1439         }
1440     }
1441
1442   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1443   Relocate_functions<32, false>::rel32(view + roff, value);
1444
1445   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1446   // We can skip it.
1447   this->skip_call_tls_get_addr_ = true;
1448 }
1449
1450 // Check the range for a TLS relocation.
1451
1452 inline void
1453 Target_i386::Relocate::check_range(const Relocate_info<32, false>* relinfo,
1454                                    size_t relnum,
1455                                    const elfcpp::Rel<32, false>& rel,
1456                                    off_t view_size, off_t off)
1457 {
1458   off_t offset = rel.get_r_offset() + off;
1459   if (offset < 0 || offset > view_size)
1460     {
1461       fprintf(stderr, _("%s: %s: TLS relocation out of range\n"),
1462               program_name,
1463               relinfo->location(relnum, rel.get_r_offset()).c_str());
1464       gold_exit(false);
1465     }
1466 }
1467
1468 // Check the validity of a TLS relocation.  This is like assert.
1469
1470 inline void
1471 Target_i386::Relocate::check_tls(const Relocate_info<32, false>* relinfo,
1472                                  size_t relnum,
1473                                  const elfcpp::Rel<32, false>& rel,
1474                                  bool valid)
1475 {
1476   if (!valid)
1477     {
1478       fprintf(stderr,
1479               _("%s: %s: TLS relocation against invalid instruction\n"),
1480               program_name,
1481               relinfo->location(relnum, rel.get_r_offset()).c_str());
1482       gold_exit(false);
1483     }
1484 }
1485
1486 // Relocate section data.
1487
1488 void
1489 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1490                               unsigned int sh_type,
1491                               const unsigned char* prelocs,
1492                               size_t reloc_count,
1493                               unsigned char* view,
1494                               elfcpp::Elf_types<32>::Elf_Addr address,
1495                               off_t view_size)
1496 {
1497   gold_assert(sh_type == elfcpp::SHT_REL);
1498
1499   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1500                          Target_i386::Relocate>(
1501     relinfo,
1502     this,
1503     prelocs,
1504     reloc_count,
1505     view,
1506     address,
1507     view_size);
1508 }
1509
1510 // Return a string used to fill a code section with nops to take up
1511 // the specified length.
1512
1513 std::string
1514 Target_i386::do_code_fill(off_t length)
1515 {
1516   if (length >= 16)
1517     {
1518       // Build a jmp instruction to skip over the bytes.
1519       unsigned char jmp[5];
1520       jmp[0] = 0xe9;
1521       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1522       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1523               + std::string(length - 5, '\0'));
1524     }
1525
1526   // Nop sequences of various lengths.
1527   const char nop1[1] = { 0x90 };                   // nop
1528   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1529   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1530   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1531   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1532                          0x00 };                   // leal 0(%esi,1),%esi
1533   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1534                          0x00, 0x00 };
1535   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1536                          0x00, 0x00, 0x00 };
1537   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1538                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1539   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1540                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1541                          0x00 };
1542   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1543                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1544                            0x00, 0x00 };
1545   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1546                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1547                            0x00, 0x00, 0x00 };
1548   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1549                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1550                            0x00, 0x00, 0x00, 0x00 };
1551   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1552                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1553                            0x27, 0x00, 0x00, 0x00,
1554                            0x00 };
1555   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1556                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1557                            0xbc, 0x27, 0x00, 0x00,
1558                            0x00, 0x00 };
1559   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1560                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1561                            0x90, 0x90, 0x90, 0x90,
1562                            0x90, 0x90, 0x90 };
1563
1564   const char* nops[16] = {
1565     NULL,
1566     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1567     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1568   };
1569
1570   return std::string(nops[length], length);
1571 }
1572
1573 // The selector for i386 object files.
1574
1575 class Target_selector_i386 : public Target_selector
1576 {
1577 public:
1578   Target_selector_i386()
1579     : Target_selector(elfcpp::EM_386, 32, false)
1580   { }
1581
1582   Target*
1583   recognize(int machine, int osabi, int abiversion);
1584
1585  private:
1586   Target_i386* target_;
1587 };
1588
1589 // Recognize an i386 object file when we already know that the machine
1590 // number is EM_386.
1591
1592 Target*
1593 Target_selector_i386::recognize(int, int, int)
1594 {
1595   if (this->target_ == NULL)
1596     this->target_ = new Target_i386();
1597   return this->target_;
1598 }
1599
1600 Target_selector_i386 target_selector_i386;
1601
1602 } // End anonymous namespace.