gold/i386.cc

   1 // i386.cc -- i386 target support for gold.
   2
   3 #include "gold.h"
   4
   5 #include <cstring>
   6
   7 #include "elfcpp.h"
   8 #include "parameters.h"
   9 #include "reloc.h"
  10 #include "i386.h"
  11 #include "object.h"
  12 #include "symtab.h"
  13 #include "layout.h"
  14 #include "output.h"
  15 #include "target.h"
  16 #include "target-reloc.h"
  17 #include "target-select.h"
  18
  19 namespace
  20 {
  21
  22 using namespace gold;
  23
  24 class Output_data_plt_i386;
  25
  26 // The i386 target class.
  27
  28 class Target_i386 : public Sized_target<32, false>
  29 {
  30  public:
  31   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
  32
  33   Target_i386()
  34     : Sized_target<32, false>(&i386_info),
  35       got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
  36       copy_relocs_(NULL), dynbss_(NULL)
  37   { }
  38
  39   // Scan the relocations to look for symbol adjustments.
  40   void
  41   scan_relocs(const General_options& options,
  42               Symbol_table* symtab,
  43               Layout* layout,
  44               Sized_relobj<32, false>* object,
  45               unsigned int data_shndx,
  46               unsigned int sh_type,
  47               const unsigned char* prelocs,
  48               size_t reloc_count,
  49               size_t local_symbol_count,
  50               const unsigned char* plocal_symbols,
  51               Symbol** global_symbols);
  52
  53   // Finalize the sections.
  54   void
  55   do_finalize_sections(Layout*);
  56
  57   // Relocate a section.
  58   void
  59   relocate_section(const Relocate_info<32, false>*,
  60                    unsigned int sh_type,
  61                    const unsigned char* prelocs,
  62                    size_t reloc_count,
  63                    unsigned char* view,
  64                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  65                    off_t view_size);
  66
  67   // Return a string used to fill a code section with nops.
  68   std::string
  69   do_code_fill(off_t length);
  70
  71  private:
  72   // The class which scans relocations.
  73   struct Scan
  74   {
  75     inline void
  76     local(const General_options& options, Symbol_table* symtab,
  77           Layout* layout, Target_i386* target,
  78           Sized_relobj<32, false>* object,
  79           unsigned int data_shndx,
  80           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
  81           const elfcpp::Sym<32, false>& lsym);
  82
  83     inline void
  84     global(const General_options& options, Symbol_table* symtab,
  85            Layout* layout, Target_i386* target,
  86            Sized_relobj<32, false>* object,
  87            unsigned int data_shndx,
  88            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
  89            Symbol* gsym);
  90   };
  91
  92   // The class which implements relocation.
  93   class Relocate
  94   {
  95    public:
  96     Relocate()
  97       : skip_call_tls_get_addr_(false)
  98     { }
  99
 100     ~Relocate()
 101     {
 102       if (this->skip_call_tls_get_addr_)
 103         {
 104           // FIXME: This needs to specify the location somehow.
 105           fprintf(stderr, _("%s: missing expected TLS relocation\n"),
 106                   program_name);
 107           gold_exit(false);
 108         }
 109     }
 110
 111     // Do a relocation.  Return false if the caller should not issue
 112     // any warnings about this relocation.
 113     inline bool
 114     relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
 115              const elfcpp::Rel<32, false>&,
 116              unsigned int r_type, const Sized_symbol<32>*,
 117              const Symbol_value<32>*,
 118              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 119              off_t);
 120
 121    private:
 122     // Do a TLS relocation.
 123     inline void
 124     relocate_tls(const Relocate_info<32, false>*, size_t relnum,
 125                  const elfcpp::Rel<32, false>&,
 126                  unsigned int r_type, const Sized_symbol<32>*,
 127                  const Symbol_value<32>*,
 128                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
 129
 130     // Do a TLS Initial-Exec to Local-Exec transition.
 131     static inline void
 132     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 133                  Output_segment* tls_segment,
 134                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 135                  elfcpp::Elf_types<32>::Elf_Addr value,
 136                  unsigned char* view,
 137                  off_t view_size);
 138
 139     // Do a TLS Global-Dynamic to Local-Exec transition.
 140     inline void
 141     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 142                  Output_segment* tls_segment,
 143                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 144                  elfcpp::Elf_types<32>::Elf_Addr value,
 145                  unsigned char* view,
 146                  off_t view_size);
 147
 148     // Check the range for a TLS relocation.
 149     static inline void
 150     check_range(const Relocate_info<32, false>*, size_t relnum,
 151                 const elfcpp::Rel<32, false>&, off_t, off_t);
 152
 153     // Check the validity of a TLS relocation.  This is like assert.
 154     static inline void
 155     check_tls(const Relocate_info<32, false>*, size_t relnum,
 156               const elfcpp::Rel<32, false>&, bool);
 157
 158     // This is set if we should skip the next reloc, which should be a
 159     // PLT32 reloc against ___tls_get_addr.
 160     bool skip_call_tls_get_addr_;
 161   };
 162
 163   // Adjust TLS relocation type based on the options and whether this
 164   // is a local symbol.
 165   static unsigned int
 166   optimize_tls_reloc(bool is_final, int r_type);
 167
 168   // Get the GOT section, creating it if necessary.
 169   Output_data_got<32, false>*
 170   got_section(Symbol_table*, Layout*);
 171
 172   // Create a PLT entry for a global symbol.
 173   void
 174   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 175
 176   // Get the PLT section.
 177   Output_data_plt_i386*
 178   plt_section() const
 179   {
 180     gold_assert(this->plt_ != NULL);
 181     return this->plt_;
 182   }
 183
 184   // Get the dynamic reloc section, creating it if necessary.
 185   Reloc_section*
 186   rel_dyn_section(Layout*);
 187
 188   // Copy a relocation against a global symbol.
 189   void
 190   copy_reloc(const General_options*, Symbol_table*, Layout*,
 191              Sized_relobj<32, false>*, unsigned int,
 192              Symbol*, const elfcpp::Rel<32, false>&);
 193
 194   // Information about this specific target which we pass to the
 195   // general Target structure.
 196   static const Target::Target_info i386_info;
 197
 198   // The GOT section.
 199   Output_data_got<32, false>* got_;
 200   // The PLT section.
 201   Output_data_plt_i386* plt_;
 202   // The GOT PLT section.
 203   Output_data_space* got_plt_;
 204   // The dynamic reloc section.
 205   Reloc_section* rel_dyn_;
 206   // Relocs saved to avoid a COPY reloc.
 207   Copy_relocs<32, false>* copy_relocs_;
 208   // Space for variables copied with a COPY reloc.
 209   Output_data_space* dynbss_;
 210 };
 211
 212 const Target::Target_info Target_i386::i386_info =
 213 {
 214   32,                   // size
 215   false,                // is_big_endian
 216   elfcpp::EM_386,       // machine_code
 217   false,                // has_make_symbol
 218   false,                // has_resolve
 219   true,                 // has_code_fill
 220   "/usr/lib/libc.so.1", // dynamic_linker
 221   0x08048000,           // text_segment_address
 222   0x1000,               // abi_pagesize
 223   0x1000                // common_pagesize
 224 };
 225
 226 // Get the GOT section, creating it if necessary.
 227
 228 Output_data_got<32, false>*
 229 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 230 {
 231   if (this->got_ == NULL)
 232     {
 233       gold_assert(symtab != NULL && layout != NULL);
 234
 235       this->got_ = new Output_data_got<32, false>();
 236
 237       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 238                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 239                                       this->got_);
 240
 241       // The old GNU linker creates a .got.plt section.  We just
 242       // create another set of data in the .got section.  Note that we
 243       // always create a PLT if we create a GOT, although the PLT
 244       // might be empty.
 245       this->got_plt_ = new Output_data_space(4);
 246       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 247                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 248                                       this->got_plt_);
 249
 250       // The first three entries are reserved.
 251       this->got_plt_->set_space_size(3 * 4);
 252
 253       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 254       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 255                                     this->got_plt_,
 256                                     0, 0, elfcpp::STT_OBJECT,
 257                                     elfcpp::STB_LOCAL,
 258                                     elfcpp::STV_HIDDEN, 0,
 259                                     false, false);
 260     }
 261
 262   return this->got_;
 263 }
 264
 265 // Get the dynamic reloc section, creating it if necessary.
 266
 267 Target_i386::Reloc_section*
 268 Target_i386::rel_dyn_section(Layout* layout)
 269 {
 270   if (this->rel_dyn_ == NULL)
 271     {
 272       gold_assert(layout != NULL);
 273       this->rel_dyn_ = new Reloc_section();
 274       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 275                                       elfcpp::SHF_ALLOC, this->rel_dyn_);
 276     }
 277   return this->rel_dyn_;
 278 }
 279
 280 // A class to handle the PLT data.
 281
 282 class Output_data_plt_i386 : public Output_section_data
 283 {
 284  public:
 285   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 286
 287   Output_data_plt_i386(Layout*, Output_data_space*);
 288
 289   // Add an entry to the PLT.
 290   void
 291   add_entry(Symbol* gsym);
 292
 293   // Return the .rel.plt section data.
 294   const Reloc_section*
 295   rel_plt() const
 296   { return this->rel_; }
 297
 298  protected:
 299   void
 300   do_adjust_output_section(Output_section* os);
 301
 302  private:
 303   // The size of an entry in the PLT.
 304   static const int plt_entry_size = 16;
 305
 306   // The first entry in the PLT for an executable.
 307   static unsigned char exec_first_plt_entry[plt_entry_size];
 308
 309   // The first entry in the PLT for a shared object.
 310   static unsigned char dyn_first_plt_entry[plt_entry_size];
 311
 312   // Other entries in the PLT for an executable.
 313   static unsigned char exec_plt_entry[plt_entry_size];
 314
 315   // Other entries in the PLT for a shared object.
 316   static unsigned char dyn_plt_entry[plt_entry_size];
 317
 318   // Set the final size.
 319   void
 320   do_set_address(uint64_t, off_t)
 321   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 322
 323   // Write out the PLT data.
 324   void
 325   do_write(Output_file*);
 326
 327   // The reloc section.
 328   Reloc_section* rel_;
 329   // The .got.plt section.
 330   Output_data_space* got_plt_;
 331   // The number of PLT entries.
 332   unsigned int count_;
 333 };
 334
 335 // Create the PLT section.  The ordinary .got section is an argument,
 336 // since we need to refer to the start.  We also create our own .got
 337 // section just for PLT entries.
 338
 339 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 340                                            Output_data_space* got_plt)
 341   : Output_section_data(4), got_plt_(got_plt)
 342 {
 343   this->rel_ = new Reloc_section();
 344   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 345                                   elfcpp::SHF_ALLOC, this->rel_);
 346 }
 347
 348 // For some reason
 349
 350 void
 351 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 352 {
 353   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 354   // linker, and so do we.
 355   os->set_entsize(4);
 356 }
 357
 358 // Add an entry to the PLT.
 359
 360 void
 361 Output_data_plt_i386::add_entry(Symbol* gsym)
 362 {
 363   gold_assert(!gsym->has_plt_offset());
 364
 365   // Note that when setting the PLT offset we skip the initial
 366   // reserved PLT entry.
 367   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 368
 369   ++this->count_;
 370
 371   off_t got_offset = this->got_plt_->data_size();
 372
 373   // Every PLT entry needs a GOT entry which points back to the PLT
 374   // entry (this will be changed by the dynamic linker, normally
 375   // lazily when the function is called).
 376   this->got_plt_->set_space_size(got_offset + 4);
 377
 378   // Every PLT entry needs a reloc.
 379   gsym->set_needs_dynsym_entry();
 380   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 381                          got_offset);
 382
 383   // Note that we don't need to save the symbol.  The contents of the
 384   // PLT are independent of which symbols are used.  The symbols only
 385   // appear in the relocations.
 386 }
 387
 388 // The first entry in the PLT for an executable.
 389
 390 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 391 {
 392   0xff, 0x35,   // pushl contents of memory address
 393   0, 0, 0, 0,   // replaced with address of .got + 4
 394   0xff, 0x25,   // jmp indirect
 395   0, 0, 0, 0,   // replaced with address of .got + 8
 396   0, 0, 0, 0    // unused
 397 };
 398
 399 // The first entry in the PLT for a shared object.
 400
 401 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 402 {
 403   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 404   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 405   0, 0, 0, 0                    // unused
 406 };
 407
 408 // Subsequent entries in the PLT for an executable.
 409
 410 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 411 {
 412   0xff, 0x25,   // jmp indirect
 413   0, 0, 0, 0,   // replaced with address of symbol in .got
 414   0x68,         // pushl immediate
 415   0, 0, 0, 0,   // replaced with offset into relocation table
 416   0xe9,         // jmp relative
 417   0, 0, 0, 0    // replaced with offset to start of .plt
 418 };
 419
 420 // Subsequent entries in the PLT for a shared object.
 421
 422 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 423 {
 424   0xff, 0xa3,   // jmp *offset(%ebx)
 425   0, 0, 0, 0,   // replaced with offset of symbol in .got
 426   0x68,         // pushl immediate
 427   0, 0, 0, 0,   // replaced with offset into relocation table
 428   0xe9,         // jmp relative
 429   0, 0, 0, 0    // replaced with offset to start of .plt
 430 };
 431
 432 // Write out the PLT.  This uses the hand-coded instructions above,
 433 // and adjusts them as needed.  This is all specified by the i386 ELF
 434 // Processor Supplement.
 435
 436 void
 437 Output_data_plt_i386::do_write(Output_file* of)
 438 {
 439   const off_t offset = this->offset();
 440   const off_t oview_size = this->data_size();
 441   unsigned char* const oview = of->get_output_view(offset, oview_size);
 442
 443   const off_t got_file_offset = this->got_plt_->offset();
 444   const off_t got_size = this->got_plt_->data_size();
 445   unsigned char* const got_view = of->get_output_view(got_file_offset,
 446                                                       got_size);
 447
 448   unsigned char* pov = oview;
 449
 450   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 451   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 452
 453   if (parameters->output_is_shared())
 454     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 455   else
 456     {
 457       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 458       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 459       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 460     }
 461   pov += plt_entry_size;
 462
 463   unsigned char* got_pov = got_view;
 464
 465   memset(got_pov, 0, 12);
 466   got_pov += 12;
 467
 468   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 469
 470   unsigned int plt_offset = plt_entry_size;
 471   unsigned int plt_rel_offset = 0;
 472   unsigned int got_offset = 12;
 473   const unsigned int count = this->count_;
 474   for (unsigned int i = 0;
 475        i < count;
 476        ++i,
 477          pov += plt_entry_size,
 478          got_pov += 4,
 479          plt_offset += plt_entry_size,
 480          plt_rel_offset += rel_size,
 481          got_offset += 4)
 482     {
 483       // Set and adjust the PLT entry itself.
 484
 485       if (parameters->output_is_shared())
 486         {
 487           memcpy(pov, dyn_plt_entry, plt_entry_size);
 488           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 489         }
 490       else
 491         {
 492           memcpy(pov, exec_plt_entry, plt_entry_size);
 493           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 494                                                       (got_address
 495                                                        + got_offset));
 496         }
 497
 498       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 499       elfcpp::Swap<32, false>::writeval(pov + 12,
 500                                         - (plt_offset + plt_entry_size));
 501
 502       // Set the entry in the GOT.
 503       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 504     }
 505
 506   gold_assert(pov - oview == oview_size);
 507   gold_assert(got_pov - got_view == got_size);
 508
 509   of->write_output_view(offset, oview_size, oview);
 510   of->write_output_view(got_file_offset, got_size, got_view);
 511 }
 512
 513 // Create a PLT entry for a global symbol.
 514
 515 void
 516 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 517 {
 518   if (gsym->has_plt_offset())
 519     return;
 520
 521   if (this->plt_ == NULL)
 522     {
 523       // Create the GOT sections first.
 524       this->got_section(symtab, layout);
 525
 526       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 527       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 528                                       (elfcpp::SHF_ALLOC
 529                                        | elfcpp::SHF_EXECINSTR),
 530                                       this->plt_);
 531     }
 532
 533   this->plt_->add_entry(gsym);
 534 }
 535
 536 // Handle a relocation against a non-function symbol defined in a
 537 // dynamic object.  The traditional way to handle this is to generate
 538 // a COPY relocation to copy the variable at runtime from the shared
 539 // object into the executable's data segment.  However, this is
 540 // undesirable in general, as if the size of the object changes in the
 541 // dynamic object, the executable will no longer work correctly.  If
 542 // this relocation is in a writable section, then we can create a
 543 // dynamic reloc and the dynamic linker will resolve it to the correct
 544 // address at runtime.  However, we do not want do that if the
 545 // relocation is in a read-only section, as it would prevent the
 546 // readonly segment from being shared.  And if we have to eventually
 547 // generate a COPY reloc, then any dynamic relocations will be
 548 // useless.  So this means that if this is a writable section, we need
 549 // to save the relocation until we see whether we have to create a
 550 // COPY relocation for this symbol for any other relocation.
 551
 552 void
 553 Target_i386::copy_reloc(const General_options* options,
 554                         Symbol_table* symtab,
 555                         Layout* layout,
 556                         Sized_relobj<32, false>* object,
 557                         unsigned int data_shndx, Symbol* gsym,
 558                         const elfcpp::Rel<32, false>& rel)
 559 {
 560   Sized_symbol<32>* ssym;
 561   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
 562                                                         SELECT_SIZE(32));
 563
 564   if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
 565                                                data_shndx, ssym))
 566     {
 567       // So far we do not need a COPY reloc.  Save this relocation.
 568       // If it turns out that we never need a COPY reloc for this
 569       // symbol, then we will emit the relocation.
 570       if (this->copy_relocs_ == NULL)
 571         this->copy_relocs_ = new Copy_relocs<32, false>();
 572       this->copy_relocs_->save(ssym, object, data_shndx, rel);
 573     }
 574   else
 575     {
 576       // Allocate space for this symbol in the .bss section.
 577
 578       elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
 579
 580       // There is no defined way to determine the required alignment
 581       // of the symbol.  We pick the alignment based on the size.  We
 582       // set an arbitrary maximum of 256.
 583       unsigned int align;
 584       for (align = 1; align < 512; align <<= 1)
 585         if ((symsize & align) != 0)
 586           break;
 587
 588       if (this->dynbss_ == NULL)
 589         {
 590           this->dynbss_ = new Output_data_space(align);
 591           layout->add_output_section_data(".bss",
 592                                           elfcpp::SHT_NOBITS,
 593                                           (elfcpp::SHF_ALLOC
 594                                            | elfcpp::SHF_WRITE),
 595                                           this->dynbss_);
 596         }
 597
 598       Output_data_space* dynbss = this->dynbss_;
 599
 600       if (align > dynbss->addralign())
 601         dynbss->set_space_alignment(align);
 602
 603       off_t dynbss_size = dynbss->data_size();
 604       dynbss_size = align_address(dynbss_size, align);
 605       off_t offset = dynbss_size;
 606       dynbss->set_space_size(dynbss_size + symsize);
 607
 608       // Define the symbol in the .dynbss section.
 609       symtab->define_in_output_data(this, ssym->name(), ssym->version(),
 610                                     dynbss, offset, symsize, ssym->type(),
 611                                     ssym->binding(), ssym->visibility(),
 612                                     ssym->nonvis(), false, false);
 613
 614       // Add the COPY reloc.
 615       ssym->set_needs_dynsym_entry();
 616       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 617       rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
 618     }
 619 }
 620
 621 // Optimize the TLS relocation type based on what we know about the
 622 // symbol.  IS_FINAL is true if the final address of this symbol is
 623 // known at link time.
 624
 625 unsigned int
 626 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 627 {
 628   // If we are generating a shared library, then we can't do anything
 629   // in the linker.
 630   if (parameters->output_is_shared())
 631     return r_type;
 632
 633   switch (r_type)
 634     {
 635     case elfcpp::R_386_TLS_GD:
 636     case elfcpp::R_386_TLS_GOTDESC:
 637     case elfcpp::R_386_TLS_DESC_CALL:
 638       // These are Global-Dynamic which permits fully general TLS
 639       // access.  Since we know that we are generating an executable,
 640       // we can convert this to Initial-Exec.  If we also know that
 641       // this is a local symbol, we can further switch to Local-Exec.
 642       if (is_final)
 643         return elfcpp::R_386_TLS_LE_32;
 644       return elfcpp::R_386_TLS_IE_32;
 645
 646     case elfcpp::R_386_TLS_LDM:
 647       // This is Local-Dynamic, which refers to a local symbol in the
 648       // dynamic TLS block.  Since we know that we generating an
 649       // executable, we can switch to Local-Exec.
 650       return elfcpp::R_386_TLS_LE_32;
 651
 652     case elfcpp::R_386_TLS_LDO_32:
 653       // Another type of Local-Dynamic relocation.
 654       return elfcpp::R_386_TLS_LE;
 655
 656     case elfcpp::R_386_TLS_IE:
 657     case elfcpp::R_386_TLS_GOTIE:
 658     case elfcpp::R_386_TLS_IE_32:
 659       // These are Initial-Exec relocs which get the thread offset
 660       // from the GOT.  If we know that we are linking against the
 661       // local symbol, we can switch to Local-Exec, which links the
 662       // thread offset into the instruction.
 663       if (is_final)
 664         return elfcpp::R_386_TLS_LE_32;
 665       return r_type;
 666
 667     case elfcpp::R_386_TLS_LE:
 668     case elfcpp::R_386_TLS_LE_32:
 669       // When we already have Local-Exec, there is nothing further we
 670       // can do.
 671       return r_type;
 672
 673     default:
 674       gold_unreachable();
 675     }
 676 }
 677
 678 // Scan a relocation for a local symbol.
 679
 680 inline void
 681 Target_i386::Scan::local(const General_options&,
 682                          Symbol_table* symtab,
 683                          Layout* layout,
 684                          Target_i386* target,
 685                          Sized_relobj<32, false>* object,
 686                          unsigned int,
 687                          const elfcpp::Rel<32, false>&,
 688                          unsigned int r_type,
 689                          const elfcpp::Sym<32, false>&)
 690 {
 691   switch (r_type)
 692     {
 693     case elfcpp::R_386_NONE:
 694     case elfcpp::R_386_GNU_VTINHERIT:
 695     case elfcpp::R_386_GNU_VTENTRY:
 696       break;
 697
 698     case elfcpp::R_386_32:
 699     case elfcpp::R_386_16:
 700     case elfcpp::R_386_8:
 701       // FIXME: If we are generating a shared object we need to copy
 702       // this relocation into the object.
 703       gold_assert(!parameters->output_is_shared());
 704       break;
 705
 706     case elfcpp::R_386_PC32:
 707     case elfcpp::R_386_PC16:
 708     case elfcpp::R_386_PC8:
 709       break;
 710
 711     case elfcpp::R_386_GOTOFF:
 712     case elfcpp::R_386_GOTPC:
 713       // We need a GOT section.
 714       target->got_section(symtab, layout);
 715       break;
 716
 717     case elfcpp::R_386_COPY:
 718     case elfcpp::R_386_GLOB_DAT:
 719     case elfcpp::R_386_JUMP_SLOT:
 720     case elfcpp::R_386_RELATIVE:
 721     case elfcpp::R_386_TLS_TPOFF:
 722     case elfcpp::R_386_TLS_DTPMOD32:
 723     case elfcpp::R_386_TLS_DTPOFF32:
 724     case elfcpp::R_386_TLS_TPOFF32:
 725     case elfcpp::R_386_TLS_DESC:
 726       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 727               program_name, object->name().c_str(), r_type);
 728       gold_exit(false);
 729       break;
 730
 731     case elfcpp::R_386_TLS_IE:
 732     case elfcpp::R_386_TLS_GOTIE:
 733     case elfcpp::R_386_TLS_LE:
 734     case elfcpp::R_386_TLS_GD:
 735     case elfcpp::R_386_TLS_LDM:
 736     case elfcpp::R_386_TLS_LDO_32:
 737     case elfcpp::R_386_TLS_IE_32:
 738     case elfcpp::R_386_TLS_LE_32:
 739     case elfcpp::R_386_TLS_GOTDESC:
 740     case elfcpp::R_386_TLS_DESC_CALL:
 741       {
 742         bool output_is_executable = parameters->output_is_executable();
 743         r_type = Target_i386::optimize_tls_reloc(output_is_executable,
 744                                                  r_type);
 745         switch (r_type)
 746           {
 747           case elfcpp::R_386_TLS_LE:
 748           case elfcpp::R_386_TLS_LE_32:
 749             // FIXME: If generating a shared object, we need to copy
 750             // this relocation into the object.
 751             gold_assert(output_is_executable);
 752             break;
 753
 754           case elfcpp::R_386_TLS_IE:
 755           case elfcpp::R_386_TLS_GOTIE:
 756           case elfcpp::R_386_TLS_GD:
 757           case elfcpp::R_386_TLS_LDM:
 758           case elfcpp::R_386_TLS_LDO_32:
 759           case elfcpp::R_386_TLS_IE_32:
 760           case elfcpp::R_386_TLS_GOTDESC:
 761           case elfcpp::R_386_TLS_DESC_CALL:
 762             fprintf(stderr,
 763                     _("%s: %s: unsupported reloc %u against local symbol\n"),
 764                     program_name, object->name().c_str(), r_type);
 765             break;
 766           }
 767       }
 768       break;
 769
 770     case elfcpp::R_386_GOT32:
 771     case elfcpp::R_386_PLT32:
 772     case elfcpp::R_386_32PLT:
 773     case elfcpp::R_386_TLS_GD_32:
 774     case elfcpp::R_386_TLS_GD_PUSH:
 775     case elfcpp::R_386_TLS_GD_CALL:
 776     case elfcpp::R_386_TLS_GD_POP:
 777     case elfcpp::R_386_TLS_LDM_32:
 778     case elfcpp::R_386_TLS_LDM_PUSH:
 779     case elfcpp::R_386_TLS_LDM_CALL:
 780     case elfcpp::R_386_TLS_LDM_POP:
 781     case elfcpp::R_386_USED_BY_INTEL_200:
 782     default:
 783       fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"),
 784               program_name, object->name().c_str(), r_type);
 785       break;
 786     }
 787 }
 788
 789 // Scan a relocation for a global symbol.
 790
 791 inline void
 792 Target_i386::Scan::global(const General_options& options,
 793                           Symbol_table* symtab,
 794                           Layout* layout,
 795                           Target_i386* target,
 796                           Sized_relobj<32, false>* object,
 797                           unsigned int data_shndx,
 798                           const elfcpp::Rel<32, false>& reloc,
 799                           unsigned int r_type,
 800                           Symbol* gsym)
 801 {
 802   switch (r_type)
 803     {
 804     case elfcpp::R_386_NONE:
 805     case elfcpp::R_386_GNU_VTINHERIT:
 806     case elfcpp::R_386_GNU_VTENTRY:
 807       break;
 808
 809     case elfcpp::R_386_32:
 810     case elfcpp::R_386_PC32:
 811     case elfcpp::R_386_16:
 812     case elfcpp::R_386_PC16:
 813     case elfcpp::R_386_8:
 814     case elfcpp::R_386_PC8:
 815       // FIXME: If we are generating a shared object we may need to
 816       // copy this relocation into the object.  If this symbol is
 817       // defined in a shared object, we may need to copy this
 818       // relocation in order to avoid a COPY relocation.
 819       gold_assert(!parameters->output_is_shared());
 820
 821       if (gsym->is_from_dynobj())
 822         {
 823           // This symbol is defined in a dynamic object.  If it is a
 824           // function, we make a PLT entry.  Otherwise we need to
 825           // either generate a COPY reloc or copy this reloc.
 826           if (gsym->type() == elfcpp::STT_FUNC)
 827             target->make_plt_entry(symtab, layout, gsym);
 828           else
 829             target->copy_reloc(&options, symtab, layout, object, data_shndx,
 830                                gsym, reloc);
 831         }
 832
 833       break;
 834
 835     case elfcpp::R_386_GOT32:
 836       {
 837         // The symbol requires a GOT entry.
 838         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 839         if (got->add_global(gsym))
 840           {
 841             // If this symbol is not fully resolved, we need to add a
 842             // dynamic relocation for it.
 843             if (!gsym->final_value_is_known())
 844               {
 845                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 846                 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
 847                                     gsym->got_offset());
 848               }
 849           }
 850       }
 851       break;
 852
 853     case elfcpp::R_386_PLT32:
 854       // If the symbol is fully resolved, this is just a PC32 reloc.
 855       // Otherwise we need a PLT entry.
 856       if (gsym->final_value_is_known())
 857         break;
 858       target->make_plt_entry(symtab, layout, gsym);
 859       break;
 860
 861     case elfcpp::R_386_GOTOFF:
 862     case elfcpp::R_386_GOTPC:
 863       // We need a GOT section.
 864       target->got_section(symtab, layout);
 865       break;
 866
 867     case elfcpp::R_386_COPY:
 868     case elfcpp::R_386_GLOB_DAT:
 869     case elfcpp::R_386_JUMP_SLOT:
 870     case elfcpp::R_386_RELATIVE:
 871     case elfcpp::R_386_TLS_TPOFF:
 872     case elfcpp::R_386_TLS_DTPMOD32:
 873     case elfcpp::R_386_TLS_DTPOFF32:
 874     case elfcpp::R_386_TLS_TPOFF32:
 875     case elfcpp::R_386_TLS_DESC:
 876       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 877               program_name, object->name().c_str(), r_type);
 878       gold_exit(false);
 879       break;
 880
 881     case elfcpp::R_386_TLS_IE:
 882     case elfcpp::R_386_TLS_GOTIE:
 883     case elfcpp::R_386_TLS_LE:
 884     case elfcpp::R_386_TLS_GD:
 885     case elfcpp::R_386_TLS_LDM:
 886     case elfcpp::R_386_TLS_LDO_32:
 887     case elfcpp::R_386_TLS_IE_32:
 888     case elfcpp::R_386_TLS_LE_32:
 889     case elfcpp::R_386_TLS_GOTDESC:
 890     case elfcpp::R_386_TLS_DESC_CALL:
 891       {
 892         const bool is_final = gsym->final_value_is_known();
 893         r_type = Target_i386::optimize_tls_reloc(is_final, r_type);
 894         switch (r_type)
 895           {
 896           case elfcpp::R_386_TLS_LE:
 897           case elfcpp::R_386_TLS_LE_32:
 898             // FIXME: If generating a shared object, we need to copy
 899             // this relocation into the object.
 900             gold_assert(!parameters->output_is_shared());
 901             break;
 902
 903           case elfcpp::R_386_TLS_IE:
 904           case elfcpp::R_386_TLS_GOTIE:
 905           case elfcpp::R_386_TLS_GD:
 906           case elfcpp::R_386_TLS_LDM:
 907           case elfcpp::R_386_TLS_LDO_32:
 908           case elfcpp::R_386_TLS_IE_32:
 909           case elfcpp::R_386_TLS_GOTDESC:
 910           case elfcpp::R_386_TLS_DESC_CALL:
 911             fprintf(stderr,
 912                     _("%s: %s: unsupported reloc %u "
 913                       "against global symbol %s\n"),
 914                     program_name, object->name().c_str(), r_type,
 915                     gsym->name());
 916             break;
 917           }
 918       }
 919       break;
 920
 921     case elfcpp::R_386_32PLT:
 922     case elfcpp::R_386_TLS_GD_32:
 923     case elfcpp::R_386_TLS_GD_PUSH:
 924     case elfcpp::R_386_TLS_GD_CALL:
 925     case elfcpp::R_386_TLS_GD_POP:
 926     case elfcpp::R_386_TLS_LDM_32:
 927     case elfcpp::R_386_TLS_LDM_PUSH:
 928     case elfcpp::R_386_TLS_LDM_CALL:
 929     case elfcpp::R_386_TLS_LDM_POP:
 930     case elfcpp::R_386_USED_BY_INTEL_200:
 931     default:
 932       fprintf(stderr,
 933               _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 934               program_name, object->name().c_str(), r_type, gsym->name());
 935       break;
 936     }
 937 }
 938
 939 // Scan relocations for a section.
 940
 941 void
 942 Target_i386::scan_relocs(const General_options& options,
 943                          Symbol_table* symtab,
 944                          Layout* layout,
 945                          Sized_relobj<32, false>* object,
 946                          unsigned int data_shndx,
 947                          unsigned int sh_type,
 948                          const unsigned char* prelocs,
 949                          size_t reloc_count,
 950                          size_t local_symbol_count,
 951                          const unsigned char* plocal_symbols,
 952                          Symbol** global_symbols)
 953 {
 954   if (sh_type == elfcpp::SHT_RELA)
 955     {
 956       fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"),
 957               program_name, object->name().c_str());
 958       gold_exit(false);
 959     }
 960
 961   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
 962                     Target_i386::Scan>(
 963     options,
 964     symtab,
 965     layout,
 966     this,
 967     object,
 968     data_shndx,
 969     prelocs,
 970     reloc_count,
 971     local_symbol_count,
 972     plocal_symbols,
 973     global_symbols);
 974 }
 975
 976 // Finalize the sections.
 977
 978 void
 979 Target_i386::do_finalize_sections(Layout* layout)
 980 {
 981   // Fill in some more dynamic tags.
 982   Output_data_dynamic* const odyn = layout->dynamic_data();
 983   if (odyn != NULL)
 984     {
 985       if (this->got_plt_ != NULL)
 986         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
 987
 988       if (this->plt_ != NULL)
 989         {
 990           const Output_data* od = this->plt_->rel_plt();
 991           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
 992           odyn->add_section_address(elfcpp::DT_JMPREL, od);
 993           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
 994         }
 995
 996       if (this->rel_dyn_ != NULL)
 997         {
 998           const Output_data* od = this->rel_dyn_;
 999           odyn->add_section_address(elfcpp::DT_REL, od);
1000           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1001           odyn->add_constant(elfcpp::DT_RELENT,
1002                              elfcpp::Elf_sizes<32>::rel_size);
1003         }
1004
1005       if (!parameters->output_is_shared())
1006         {
1007           // The value of the DT_DEBUG tag is filled in by the dynamic
1008           // linker at run time, and used by the debugger.
1009           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1010         }
1011     }
1012
1013   // Emit any relocs we saved in an attempt to avoid generating COPY
1014   // relocs.
1015   if (this->copy_relocs_ == NULL)
1016     return;
1017   if (this->copy_relocs_->any_to_emit())
1018     {
1019       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1020       this->copy_relocs_->emit(rel_dyn);
1021     }
1022   delete this->copy_relocs_;
1023   this->copy_relocs_ = NULL;
1024 }
1025
1026 // Perform a relocation.
1027
1028 inline bool
1029 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1030                                 Target_i386* target,
1031                                 size_t relnum,
1032                                 const elfcpp::Rel<32, false>& rel,
1033                                 unsigned int r_type,
1034                                 const Sized_symbol<32>* gsym,
1035                                 const Symbol_value<32>* psymval,
1036                                 unsigned char* view,
1037                                 elfcpp::Elf_types<32>::Elf_Addr address,
1038                                 off_t view_size)
1039 {
1040   if (this->skip_call_tls_get_addr_)
1041     {
1042       if (r_type != elfcpp::R_386_PLT32
1043           || gsym == NULL
1044           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1045         {
1046           fprintf(stderr, _("%s: %s: missing expected TLS relocation\n"),
1047                   program_name,
1048                   relinfo->location(relnum, rel.get_r_offset()).c_str());
1049           gold_exit(false);
1050         }
1051
1052       this->skip_call_tls_get_addr_ = false;
1053
1054       return false;
1055     }
1056
1057   // Pick the value to use for symbols defined in shared objects.
1058   Symbol_value<32> symval;
1059   if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset())
1060     {
1061       symval.set_output_value(target->plt_section()->address()
1062                               + gsym->plt_offset());
1063       psymval = &symval;
1064     }
1065
1066   const Sized_relobj<32, false>* object = relinfo->object;
1067
1068   switch (r_type)
1069     {
1070     case elfcpp::R_386_NONE:
1071     case elfcpp::R_386_GNU_VTINHERIT:
1072     case elfcpp::R_386_GNU_VTENTRY:
1073       break;
1074
1075     case elfcpp::R_386_32:
1076       Relocate_functions<32, false>::rel32(view, object, psymval);
1077       break;
1078
1079     case elfcpp::R_386_PC32:
1080       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1081       break;
1082
1083     case elfcpp::R_386_16:
1084       Relocate_functions<32, false>::rel16(view, object, psymval);
1085       break;
1086
1087     case elfcpp::R_386_PC16:
1088       Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1089       break;
1090
1091     case elfcpp::R_386_8:
1092       Relocate_functions<32, false>::rel8(view, object, psymval);
1093       break;
1094
1095     case elfcpp::R_386_PC8:
1096       Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1097       break;
1098
1099     case elfcpp::R_386_PLT32:
1100       gold_assert(gsym->has_plt_offset()
1101                   || gsym->final_value_is_known());
1102       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1103       break;
1104
1105     case elfcpp::R_386_GOT32:
1106       // Local GOT offsets not yet supported.
1107       gold_assert(gsym);
1108       gold_assert(gsym->has_got_offset());
1109       Relocate_functions<32, false>::rel32(view, gsym->got_offset());
1110       break;
1111
1112     case elfcpp::R_386_GOTOFF:
1113       {
1114         elfcpp::Elf_types<32>::Elf_Addr value;
1115         value = (psymval->value(object, 0)
1116                  - target->got_section(NULL, NULL)->address());
1117         Relocate_functions<32, false>::rel32(view, value);
1118       }
1119       break;
1120
1121     case elfcpp::R_386_GOTPC:
1122       {
1123         elfcpp::Elf_types<32>::Elf_Addr value;
1124         value = target->got_section(NULL, NULL)->address();
1125         Relocate_functions<32, false>::pcrel32(view, value, address);
1126       }
1127       break;
1128
1129     case elfcpp::R_386_COPY:
1130     case elfcpp::R_386_GLOB_DAT:
1131     case elfcpp::R_386_JUMP_SLOT:
1132     case elfcpp::R_386_RELATIVE:
1133     case elfcpp::R_386_TLS_TPOFF:
1134     case elfcpp::R_386_TLS_DTPMOD32:
1135     case elfcpp::R_386_TLS_DTPOFF32:
1136     case elfcpp::R_386_TLS_TPOFF32:
1137     case elfcpp::R_386_TLS_DESC:
1138       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
1139               program_name,
1140               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1141               r_type);
1142       gold_exit(false);
1143       break;
1144
1145     case elfcpp::R_386_TLS_IE:
1146     case elfcpp::R_386_TLS_GOTIE:
1147     case elfcpp::R_386_TLS_LE:
1148     case elfcpp::R_386_TLS_GD:
1149     case elfcpp::R_386_TLS_LDM:
1150     case elfcpp::R_386_TLS_LDO_32:
1151     case elfcpp::R_386_TLS_IE_32:
1152     case elfcpp::R_386_TLS_LE_32:
1153     case elfcpp::R_386_TLS_GOTDESC:
1154     case elfcpp::R_386_TLS_DESC_CALL:
1155       this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1156                          address, view_size);
1157       break;
1158
1159     case elfcpp::R_386_32PLT:
1160     case elfcpp::R_386_TLS_GD_32:
1161     case elfcpp::R_386_TLS_GD_PUSH:
1162     case elfcpp::R_386_TLS_GD_CALL:
1163     case elfcpp::R_386_TLS_GD_POP:
1164     case elfcpp::R_386_TLS_LDM_32:
1165     case elfcpp::R_386_TLS_LDM_PUSH:
1166     case elfcpp::R_386_TLS_LDM_CALL:
1167     case elfcpp::R_386_TLS_LDM_POP:
1168     case elfcpp::R_386_USED_BY_INTEL_200:
1169     default:
1170       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1171               program_name,
1172               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1173               r_type);
1174       // gold_exit(false);
1175       break;
1176     }
1177
1178   return true;
1179 }
1180
1181 // Perform a TLS relocation.
1182
1183 inline void
1184 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1185                                     size_t relnum,
1186                                     const elfcpp::Rel<32, false>& rel,
1187                                     unsigned int r_type,
1188                                     const Sized_symbol<32>* gsym,
1189                                     const Symbol_value<32>* psymval,
1190                                     unsigned char* view,
1191                                     elfcpp::Elf_types<32>::Elf_Addr,
1192                                     off_t view_size)
1193 {
1194   Output_segment* tls_segment = relinfo->layout->tls_segment();
1195   if (tls_segment == NULL)
1196     {
1197       fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"),
1198               program_name,
1199               relinfo->location(relnum, rel.get_r_offset()).c_str());
1200       gold_exit(false);
1201     }
1202
1203   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1204
1205   const bool is_final = (gsym == NULL
1206                          ? !parameters->output_is_shared()
1207                          : gsym->final_value_is_known());
1208   const unsigned int opt_r_type =
1209     Target_i386::optimize_tls_reloc(is_final, r_type);
1210   switch (r_type)
1211     {
1212     case elfcpp::R_386_TLS_LE_32:
1213       value = tls_segment->vaddr() + tls_segment->memsz() - value;
1214       Relocate_functions<32, false>::rel32(view, value);
1215       break;
1216
1217     case elfcpp::R_386_TLS_LE:
1218       value = value - (tls_segment->vaddr() + tls_segment->memsz());
1219       Relocate_functions<32, false>::rel32(view, value);
1220       break;
1221
1222     case elfcpp::R_386_TLS_IE:
1223     case elfcpp::R_386_TLS_GOTIE:
1224     case elfcpp::R_386_TLS_IE_32:
1225       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1226         {
1227           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1228                                               rel, r_type, value, view,
1229                                               view_size);
1230           break;
1231         }
1232       fprintf(stderr, _("%s: %s: unsupported reloc type %u\n"),
1233               program_name,
1234               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1235               r_type);
1236       // gold_exit(false);
1237       break;
1238
1239     case elfcpp::R_386_TLS_GD:
1240       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1241         {
1242           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1243                              rel, r_type, value, view,
1244                              view_size);
1245           break;
1246         }
1247       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1248               program_name,
1249               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1250               r_type);
1251       // gold_exit(false);
1252       break;
1253
1254     case elfcpp::R_386_TLS_LDM:
1255     case elfcpp::R_386_TLS_LDO_32:
1256     case elfcpp::R_386_TLS_GOTDESC:
1257     case elfcpp::R_386_TLS_DESC_CALL:
1258       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1259               program_name,
1260               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1261               r_type);
1262       // gold_exit(false);
1263       break;
1264     }
1265 }
1266
1267 // Do a relocation in which we convert a TLS Initial-Exec to a
1268 // Local-Exec.
1269
1270 inline void
1271 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1272                                     size_t relnum,
1273                                     Output_segment* tls_segment,
1274                                     const elfcpp::Rel<32, false>& rel,
1275                                     unsigned int r_type,
1276                                     elfcpp::Elf_types<32>::Elf_Addr value,
1277                                     unsigned char* view,
1278                                     off_t view_size)
1279 {
1280   // We have to actually change the instructions, which means that we
1281   // need to examine the opcodes to figure out which instruction we
1282   // are looking at.
1283   if (r_type == elfcpp::R_386_TLS_IE)
1284     {
1285       // movl %gs:XX,%eax  ==>  movl $YY,%eax
1286       // movl %gs:XX,%reg  ==>  movl $YY,%reg
1287       // addl %gs:XX,%reg  ==>  addl $YY,%reg
1288       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -1);
1289       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1290
1291       unsigned char op1 = view[-1];
1292       if (op1 == 0xa1)
1293         {
1294           // movl XX,%eax  ==>  movl $YY,%eax
1295           view[-1] = 0xb8;
1296         }
1297       else
1298         {
1299           Target_i386::Relocate::check_range(relinfo, relnum, rel,
1300                                              view_size, -2);
1301
1302           unsigned char op2 = view[-2];
1303           if (op2 == 0x8b)
1304             {
1305               // movl XX,%reg  ==>  movl $YY,%reg
1306               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1307                                                (op1 & 0xc7) == 0x05);
1308               view[-2] = 0xc7;
1309               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1310             }
1311           else if (op2 == 0x03)
1312             {
1313               // addl XX,%reg  ==>  addl $YY,%reg
1314               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1315                                                (op1 & 0xc7) == 0x05);
1316               view[-2] = 0x81;
1317               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1318             }
1319           else
1320             Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1321         }
1322     }
1323   else
1324     {
1325       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1326       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1327       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1328       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1329       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1330
1331       unsigned char op1 = view[-1];
1332       unsigned char op2 = view[-2];
1333       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1334                                        (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1335       if (op2 == 0x8b)
1336         {
1337           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1338           view[-2] = 0xc7;
1339           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1340         }
1341       else if (op2 == 0x2b)
1342         {
1343           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1344           view[-2] = 0x81;
1345           view[-1] = 0xe8 | ((op1 >> 3) & 7);
1346         }
1347       else if (op2 == 0x03)
1348         {
1349           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1350           view[-2] = 0x81;
1351           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1352         }
1353       else
1354         Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1355     }
1356
1357   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1358   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1359     value = - value;
1360
1361   Relocate_functions<32, false>::rel32(view, value);
1362 }
1363
1364 // Do a relocation in which we convert a TLS Global-Dynamic to a
1365 // Local-Exec.
1366
1367 inline void
1368 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1369                                     size_t relnum,
1370                                     Output_segment* tls_segment,
1371                                     const elfcpp::Rel<32, false>& rel,
1372                                     unsigned int,
1373                                     elfcpp::Elf_types<32>::Elf_Addr value,
1374                                     unsigned char* view,
1375                                     off_t view_size)
1376 {
1377   // leal foo(,%reg,1),%eax; call ___tls_get_addr
1378   //  ==> movl %gs,0,%eax; subl $foo@tpoff,%eax
1379   // leal foo(%reg),%eax; call ___tls_get_addr
1380   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1381
1382   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1383   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 9);
1384
1385   unsigned char op1 = view[-1];
1386   unsigned char op2 = view[-2];
1387
1388   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1389                                    op2 == 0x8d || op2 == 0x04);
1390   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1391                                    view[4] == 0xe8);
1392
1393   int roff = 5;
1394
1395   if (op2 == 0x04)
1396     {
1397       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -3);
1398       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1399                                        view[-3] == 0x8d);
1400       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1401                                        ((op1 & 0xc7) == 0x05
1402                                         && op1 != (4 << 3)));
1403       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1404     }
1405   else
1406     {
1407       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1408                                        (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1409       if (rel.get_r_offset() + 9 < view_size && view[9] == 0x90)
1410         {
1411           // There is a trailing nop.  Use the size byte subl.
1412           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1413           roff = 6;
1414         }
1415       else
1416         {
1417           // Use the five byte subl.
1418           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1419         }
1420     }
1421
1422   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1423   Relocate_functions<32, false>::rel32(view + roff, value);
1424
1425   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1426   // We can skip it.
1427   this->skip_call_tls_get_addr_ = true;
1428 }
1429
1430 // Check the range for a TLS relocation.
1431
1432 inline void
1433 Target_i386::Relocate::check_range(const Relocate_info<32, false>* relinfo,
1434                                    size_t relnum,
1435                                    const elfcpp::Rel<32, false>& rel,
1436                                    off_t view_size, off_t off)
1437 {
1438   off_t offset = rel.get_r_offset() + off;
1439   if (offset < 0 || offset > view_size)
1440     {
1441       fprintf(stderr, _("%s: %s: TLS relocation out of range\n"),
1442               program_name,
1443               relinfo->location(relnum, rel.get_r_offset()).c_str());
1444       gold_exit(false);
1445     }
1446 }
1447
1448 // Check the validity of a TLS relocation.  This is like assert.
1449
1450 inline void
1451 Target_i386::Relocate::check_tls(const Relocate_info<32, false>* relinfo,
1452                                  size_t relnum,
1453                                  const elfcpp::Rel<32, false>& rel,
1454                                  bool valid)
1455 {
1456   if (!valid)
1457     {
1458       fprintf(stderr,
1459               _("%s: %s: TLS relocation against invalid instruction\n"),
1460               program_name,
1461               relinfo->location(relnum, rel.get_r_offset()).c_str());
1462       gold_exit(false);
1463     }
1464 }
1465
1466 // Relocate section data.
1467
1468 void
1469 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1470                               unsigned int sh_type,
1471                               const unsigned char* prelocs,
1472                               size_t reloc_count,
1473                               unsigned char* view,
1474                               elfcpp::Elf_types<32>::Elf_Addr address,
1475                               off_t view_size)
1476 {
1477   gold_assert(sh_type == elfcpp::SHT_REL);
1478
1479   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1480                          Target_i386::Relocate>(
1481     relinfo,
1482     this,
1483     prelocs,
1484     reloc_count,
1485     view,
1486     address,
1487     view_size);
1488 }
1489
1490 // Return a string used to fill a code section with nops to take up
1491 // the specified length.
1492
1493 std::string
1494 Target_i386::do_code_fill(off_t length)
1495 {
1496   if (length >= 16)
1497     {
1498       // Build a jmp instruction to skip over the bytes.
1499       unsigned char jmp[5];
1500       jmp[0] = 0xe9;
1501       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1502       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1503               + std::string(length - 5, '\0'));
1504     }
1505
1506   // Nop sequences of various lengths.
1507   const char nop1[1] = { 0x90 };                   // nop
1508   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1509   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1510   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1511   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1512                          0x00 };                   // leal 0(%esi,1),%esi
1513   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1514                          0x00, 0x00 };
1515   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1516                          0x00, 0x00, 0x00 };
1517   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1518                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1519   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1520                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1521                          0x00 };
1522   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1523                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1524                            0x00, 0x00 };
1525   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1526                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1527                            0x00, 0x00, 0x00 };
1528   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1529                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1530                            0x00, 0x00, 0x00, 0x00 };
1531   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1532                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1533                            0x27, 0x00, 0x00, 0x00,
1534                            0x00 };
1535   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1536                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1537                            0xbc, 0x27, 0x00, 0x00,
1538                            0x00, 0x00 };
1539   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1540                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1541                            0x90, 0x90, 0x90, 0x90,
1542                            0x90, 0x90, 0x90 };
1543
1544   const char* nops[16] = {
1545     NULL,
1546     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1547     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1548   };
1549
1550   return std::string(nops[length], length);
1551 }
1552
1553 // The selector for i386 object files.
1554
1555 class Target_selector_i386 : public Target_selector
1556 {
1557 public:
1558   Target_selector_i386()
1559     : Target_selector(elfcpp::EM_386, 32, false)
1560   { }
1561
1562   Target*
1563   recognize(int machine, int osabi, int abiversion);
1564
1565  private:
1566   Target_i386* target_;
1567 };
1568
1569 // Recognize an i386 object file when we already know that the machine
1570 // number is EM_386.
1571
1572 Target*
1573 Target_selector_i386::recognize(int, int, int)
1574 {
1575   if (this->target_ == NULL)
1576     this->target_ = new Target_i386();
1577   return this->target_;
1578 }
1579
1580 Target_selector_i386 target_selector_i386;
1581
1582 } // End anonymous namespace.