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   // Return the value to use for a dynamic which requires special
  78   // treatment.
  79   uint64_t
  80   do_dynsym_value(const Symbol*) const;
  81
  82   // Relocate a section.
  83   void
  84   relocate_section(const Relocate_info<32, false>*,
  85                    unsigned int sh_type,
  86                    const unsigned char* prelocs,
  87                    size_t reloc_count,
  88                    unsigned char* view,
  89                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  90                    off_t view_size);
  91
  92   // Return a string used to fill a code section with nops.
  93   std::string
  94   do_code_fill(off_t length);
  95
  96  private:
  97   // The class which scans relocations.
  98   struct Scan
  99   {
 100     inline void
 101     local(const General_options& options, Symbol_table* symtab,
 102           Layout* layout, Target_i386* target,
 103           Sized_relobj<32, false>* object,
 104           unsigned int data_shndx,
 105           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 106           const elfcpp::Sym<32, false>& lsym);
 107
 108     inline void
 109     global(const General_options& options, Symbol_table* symtab,
 110            Layout* layout, Target_i386* target,
 111            Sized_relobj<32, false>* object,
 112            unsigned int data_shndx,
 113            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 114            Symbol* gsym);
 115   };
 116
 117   // The class which implements relocation.
 118   class Relocate
 119   {
 120    public:
 121     Relocate()
 122       : skip_call_tls_get_addr_(false)
 123     { }
 124
 125     ~Relocate()
 126     {
 127       if (this->skip_call_tls_get_addr_)
 128         {
 129           // FIXME: This needs to specify the location somehow.
 130           fprintf(stderr, _("%s: missing expected TLS relocation\n"),
 131                   program_name);
 132           gold_exit(false);
 133         }
 134     }
 135
 136     // Do a relocation.  Return false if the caller should not issue
 137     // any warnings about this relocation.
 138     inline bool
 139     relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
 140              const elfcpp::Rel<32, false>&,
 141              unsigned int r_type, const Sized_symbol<32>*,
 142              const Symbol_value<32>*,
 143              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 144              off_t);
 145
 146    private:
 147     // Do a TLS relocation.
 148     inline void
 149     relocate_tls(const Relocate_info<32, false>*, size_t relnum,
 150                  const elfcpp::Rel<32, false>&,
 151                  unsigned int r_type, const Sized_symbol<32>*,
 152                  const Symbol_value<32>*,
 153                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
 154
 155     // Do a TLS Initial-Exec to Local-Exec transition.
 156     static inline void
 157     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 158                  Output_segment* tls_segment,
 159                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 160                  elfcpp::Elf_types<32>::Elf_Addr value,
 161                  unsigned char* view,
 162                  off_t view_size);
 163
 164     // Do a TLS Global-Dynamic to Local-Exec transition.
 165     inline void
 166     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 167                  Output_segment* tls_segment,
 168                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 169                  elfcpp::Elf_types<32>::Elf_Addr value,
 170                  unsigned char* view,
 171                  off_t view_size);
 172
 173     // Check the range for a TLS relocation.
 174     static inline void
 175     check_range(const Relocate_info<32, false>*, size_t relnum,
 176                 const elfcpp::Rel<32, false>&, off_t, off_t);
 177
 178     // Check the validity of a TLS relocation.  This is like assert.
 179     static inline void
 180     check_tls(const Relocate_info<32, false>*, size_t relnum,
 181               const elfcpp::Rel<32, false>&, bool);
 182
 183     // This is set if we should skip the next reloc, which should be a
 184     // PLT32 reloc against ___tls_get_addr.
 185     bool skip_call_tls_get_addr_;
 186   };
 187
 188   // Adjust TLS relocation type based on the options and whether this
 189   // is a local symbol.
 190   static unsigned int
 191   optimize_tls_reloc(bool is_final, int r_type);
 192
 193   // Get the GOT section, creating it if necessary.
 194   Output_data_got<32, false>*
 195   got_section(Symbol_table*, Layout*);
 196
 197   // Create a PLT entry for a global symbol.
 198   void
 199   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 200
 201   // Get the PLT section.
 202   const Output_data_plt_i386*
 203   plt_section() const
 204   {
 205     gold_assert(this->plt_ != NULL);
 206     return this->plt_;
 207   }
 208
 209   // Get the dynamic reloc section, creating it if necessary.
 210   Reloc_section*
 211   rel_dyn_section(Layout*);
 212
 213   // Copy a relocation against a global symbol.
 214   void
 215   copy_reloc(const General_options*, Symbol_table*, Layout*,
 216              Sized_relobj<32, false>*, unsigned int,
 217              Symbol*, const elfcpp::Rel<32, false>&);
 218
 219   // Information about this specific target which we pass to the
 220   // general Target structure.
 221   static const Target::Target_info i386_info;
 222
 223   // The GOT section.
 224   Output_data_got<32, false>* got_;
 225   // The PLT section.
 226   Output_data_plt_i386* plt_;
 227   // The GOT PLT section.
 228   Output_data_space* got_plt_;
 229   // The dynamic reloc section.
 230   Reloc_section* rel_dyn_;
 231   // Relocs saved to avoid a COPY reloc.
 232   Copy_relocs<32, false>* copy_relocs_;
 233   // Space for variables copied with a COPY reloc.
 234   Output_data_space* dynbss_;
 235 };
 236
 237 const Target::Target_info Target_i386::i386_info =
 238 {
 239   32,                   // size
 240   false,                // is_big_endian
 241   elfcpp::EM_386,       // machine_code
 242   false,                // has_make_symbol
 243   false,                // has_resolve
 244   true,                 // has_code_fill
 245   "/usr/lib/libc.so.1", // dynamic_linker
 246   0x08048000,           // text_segment_address
 247   0x1000,               // abi_pagesize
 248   0x1000                // common_pagesize
 249 };
 250
 251 // Get the GOT section, creating it if necessary.
 252
 253 Output_data_got<32, false>*
 254 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 255 {
 256   if (this->got_ == NULL)
 257     {
 258       gold_assert(symtab != NULL && layout != NULL);
 259
 260       this->got_ = new Output_data_got<32, false>();
 261
 262       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 263                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 264                                       this->got_);
 265
 266       // The old GNU linker creates a .got.plt section.  We just
 267       // create another set of data in the .got section.  Note that we
 268       // always create a PLT if we create a GOT, although the PLT
 269       // might be empty.
 270       this->got_plt_ = new Output_data_space(4);
 271       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 272                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 273                                       this->got_plt_);
 274
 275       // The first three entries are reserved.
 276       this->got_plt_->set_space_size(3 * 4);
 277
 278       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 279       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 280                                     this->got_plt_,
 281                                     0, 0, elfcpp::STT_OBJECT,
 282                                     elfcpp::STB_LOCAL,
 283                                     elfcpp::STV_HIDDEN, 0,
 284                                     false, false);
 285     }
 286
 287   return this->got_;
 288 }
 289
 290 // Get the dynamic reloc section, creating it if necessary.
 291
 292 Target_i386::Reloc_section*
 293 Target_i386::rel_dyn_section(Layout* layout)
 294 {
 295   if (this->rel_dyn_ == NULL)
 296     {
 297       gold_assert(layout != NULL);
 298       this->rel_dyn_ = new Reloc_section();
 299       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 300                                       elfcpp::SHF_ALLOC, this->rel_dyn_);
 301     }
 302   return this->rel_dyn_;
 303 }
 304
 305 // A class to handle the PLT data.
 306
 307 class Output_data_plt_i386 : public Output_section_data
 308 {
 309  public:
 310   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 311
 312   Output_data_plt_i386(Layout*, Output_data_space*);
 313
 314   // Add an entry to the PLT.
 315   void
 316   add_entry(Symbol* gsym);
 317
 318   // Return the .rel.plt section data.
 319   const Reloc_section*
 320   rel_plt() const
 321   { return this->rel_; }
 322
 323  protected:
 324   void
 325   do_adjust_output_section(Output_section* os);
 326
 327  private:
 328   // The size of an entry in the PLT.
 329   static const int plt_entry_size = 16;
 330
 331   // The first entry in the PLT for an executable.
 332   static unsigned char exec_first_plt_entry[plt_entry_size];
 333
 334   // The first entry in the PLT for a shared object.
 335   static unsigned char dyn_first_plt_entry[plt_entry_size];
 336
 337   // Other entries in the PLT for an executable.
 338   static unsigned char exec_plt_entry[plt_entry_size];
 339
 340   // Other entries in the PLT for a shared object.
 341   static unsigned char dyn_plt_entry[plt_entry_size];
 342
 343   // Set the final size.
 344   void
 345   do_set_address(uint64_t, off_t)
 346   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 347
 348   // Write out the PLT data.
 349   void
 350   do_write(Output_file*);
 351
 352   // The reloc section.
 353   Reloc_section* rel_;
 354   // The .got.plt section.
 355   Output_data_space* got_plt_;
 356   // The number of PLT entries.
 357   unsigned int count_;
 358 };
 359
 360 // Create the PLT section.  The ordinary .got section is an argument,
 361 // since we need to refer to the start.  We also create our own .got
 362 // section just for PLT entries.
 363
 364 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 365                                            Output_data_space* got_plt)
 366   : Output_section_data(4), got_plt_(got_plt), count_(0)
 367 {
 368   this->rel_ = new Reloc_section();
 369   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 370                                   elfcpp::SHF_ALLOC, this->rel_);
 371 }
 372
 373 void
 374 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 375 {
 376   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 377   // linker, and so do we.
 378   os->set_entsize(4);
 379 }
 380
 381 // Add an entry to the PLT.
 382
 383 void
 384 Output_data_plt_i386::add_entry(Symbol* gsym)
 385 {
 386   gold_assert(!gsym->has_plt_offset());
 387
 388   // Note that when setting the PLT offset we skip the initial
 389   // reserved PLT entry.
 390   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 391
 392   ++this->count_;
 393
 394   off_t got_offset = this->got_plt_->data_size();
 395
 396   // Every PLT entry needs a GOT entry which points back to the PLT
 397   // entry (this will be changed by the dynamic linker, normally
 398   // lazily when the function is called).
 399   this->got_plt_->set_space_size(got_offset + 4);
 400
 401   // Every PLT entry needs a reloc.
 402   gsym->set_needs_dynsym_entry();
 403   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 404                          got_offset);
 405
 406   // Note that we don't need to save the symbol.  The contents of the
 407   // PLT are independent of which symbols are used.  The symbols only
 408   // appear in the relocations.
 409 }
 410
 411 // The first entry in the PLT for an executable.
 412
 413 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 414 {
 415   0xff, 0x35,   // pushl contents of memory address
 416   0, 0, 0, 0,   // replaced with address of .got + 4
 417   0xff, 0x25,   // jmp indirect
 418   0, 0, 0, 0,   // replaced with address of .got + 8
 419   0, 0, 0, 0    // unused
 420 };
 421
 422 // The first entry in the PLT for a shared object.
 423
 424 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 425 {
 426   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 427   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 428   0, 0, 0, 0                    // unused
 429 };
 430
 431 // Subsequent entries in the PLT for an executable.
 432
 433 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 434 {
 435   0xff, 0x25,   // jmp indirect
 436   0, 0, 0, 0,   // replaced with address of symbol in .got
 437   0x68,         // pushl immediate
 438   0, 0, 0, 0,   // replaced with offset into relocation table
 439   0xe9,         // jmp relative
 440   0, 0, 0, 0    // replaced with offset to start of .plt
 441 };
 442
 443 // Subsequent entries in the PLT for a shared object.
 444
 445 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 446 {
 447   0xff, 0xa3,   // jmp *offset(%ebx)
 448   0, 0, 0, 0,   // replaced with offset of symbol in .got
 449   0x68,         // pushl immediate
 450   0, 0, 0, 0,   // replaced with offset into relocation table
 451   0xe9,         // jmp relative
 452   0, 0, 0, 0    // replaced with offset to start of .plt
 453 };
 454
 455 // Write out the PLT.  This uses the hand-coded instructions above,
 456 // and adjusts them as needed.  This is all specified by the i386 ELF
 457 // Processor Supplement.
 458
 459 void
 460 Output_data_plt_i386::do_write(Output_file* of)
 461 {
 462   const off_t offset = this->offset();
 463   const off_t oview_size = this->data_size();
 464   unsigned char* const oview = of->get_output_view(offset, oview_size);
 465
 466   const off_t got_file_offset = this->got_plt_->offset();
 467   const off_t got_size = this->got_plt_->data_size();
 468   unsigned char* const got_view = of->get_output_view(got_file_offset,
 469                                                       got_size);
 470
 471   unsigned char* pov = oview;
 472
 473   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 474   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 475
 476   if (parameters->output_is_shared())
 477     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 478   else
 479     {
 480       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 481       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 482       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 483     }
 484   pov += plt_entry_size;
 485
 486   unsigned char* got_pov = got_view;
 487
 488   memset(got_pov, 0, 12);
 489   got_pov += 12;
 490
 491   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 492
 493   unsigned int plt_offset = plt_entry_size;
 494   unsigned int plt_rel_offset = 0;
 495   unsigned int got_offset = 12;
 496   const unsigned int count = this->count_;
 497   for (unsigned int i = 0;
 498        i < count;
 499        ++i,
 500          pov += plt_entry_size,
 501          got_pov += 4,
 502          plt_offset += plt_entry_size,
 503          plt_rel_offset += rel_size,
 504          got_offset += 4)
 505     {
 506       // Set and adjust the PLT entry itself.
 507
 508       if (parameters->output_is_shared())
 509         {
 510           memcpy(pov, dyn_plt_entry, plt_entry_size);
 511           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 512         }
 513       else
 514         {
 515           memcpy(pov, exec_plt_entry, plt_entry_size);
 516           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 517                                                       (got_address
 518                                                        + got_offset));
 519         }
 520
 521       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 522       elfcpp::Swap<32, false>::writeval(pov + 12,
 523                                         - (plt_offset + plt_entry_size));
 524
 525       // Set the entry in the GOT.
 526       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 527     }
 528
 529   gold_assert(pov - oview == oview_size);
 530   gold_assert(got_pov - got_view == got_size);
 531
 532   of->write_output_view(offset, oview_size, oview);
 533   of->write_output_view(got_file_offset, got_size, got_view);
 534 }
 535
 536 // Create a PLT entry for a global symbol.
 537
 538 void
 539 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 540 {
 541   if (gsym->has_plt_offset())
 542     return;
 543
 544   if (this->plt_ == NULL)
 545     {
 546       // Create the GOT sections first.
 547       this->got_section(symtab, layout);
 548
 549       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 550       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 551                                       (elfcpp::SHF_ALLOC
 552                                        | elfcpp::SHF_EXECINSTR),
 553                                       this->plt_);
 554     }
 555
 556   this->plt_->add_entry(gsym);
 557 }
 558
 559 // Handle a relocation against a non-function symbol defined in a
 560 // dynamic object.  The traditional way to handle this is to generate
 561 // a COPY relocation to copy the variable at runtime from the shared
 562 // object into the executable's data segment.  However, this is
 563 // undesirable in general, as if the size of the object changes in the
 564 // dynamic object, the executable will no longer work correctly.  If
 565 // this relocation is in a writable section, then we can create a
 566 // dynamic reloc and the dynamic linker will resolve it to the correct
 567 // address at runtime.  However, we do not want do that if the
 568 // relocation is in a read-only section, as it would prevent the
 569 // readonly segment from being shared.  And if we have to eventually
 570 // generate a COPY reloc, then any dynamic relocations will be
 571 // useless.  So this means that if this is a writable section, we need
 572 // to save the relocation until we see whether we have to create a
 573 // COPY relocation for this symbol for any other relocation.
 574
 575 void
 576 Target_i386::copy_reloc(const General_options* options,
 577                         Symbol_table* symtab,
 578                         Layout* layout,
 579                         Sized_relobj<32, false>* object,
 580                         unsigned int data_shndx, Symbol* gsym,
 581                         const elfcpp::Rel<32, false>& rel)
 582 {
 583   Sized_symbol<32>* ssym;
 584   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
 585                                                         SELECT_SIZE(32));
 586
 587   if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
 588                                                data_shndx, ssym))
 589     {
 590       // So far we do not need a COPY reloc.  Save this relocation.
 591       // If it turns out that we never need a COPY reloc for this
 592       // symbol, then we will emit the relocation.
 593       if (this->copy_relocs_ == NULL)
 594         this->copy_relocs_ = new Copy_relocs<32, false>();
 595       this->copy_relocs_->save(ssym, object, data_shndx, rel);
 596     }
 597   else
 598     {
 599       // Allocate space for this symbol in the .bss section.
 600
 601       elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
 602
 603       // There is no defined way to determine the required alignment
 604       // of the symbol.  We pick the alignment based on the size.  We
 605       // set an arbitrary maximum of 256.
 606       unsigned int align;
 607       for (align = 1; align < 512; align <<= 1)
 608         if ((symsize & align) != 0)
 609           break;
 610
 611       if (this->dynbss_ == NULL)
 612         {
 613           this->dynbss_ = new Output_data_space(align);
 614           layout->add_output_section_data(".bss",
 615                                           elfcpp::SHT_NOBITS,
 616                                           (elfcpp::SHF_ALLOC
 617                                            | elfcpp::SHF_WRITE),
 618                                           this->dynbss_);
 619         }
 620
 621       Output_data_space* dynbss = this->dynbss_;
 622
 623       if (align > dynbss->addralign())
 624         dynbss->set_space_alignment(align);
 625
 626       off_t dynbss_size = dynbss->data_size();
 627       dynbss_size = align_address(dynbss_size, align);
 628       off_t offset = dynbss_size;
 629       dynbss->set_space_size(dynbss_size + symsize);
 630
 631       // Define the symbol in the .dynbss section.
 632       symtab->define_in_output_data(this, ssym->name(), ssym->version(),
 633                                     dynbss, offset, symsize, ssym->type(),
 634                                     ssym->binding(), ssym->visibility(),
 635                                     ssym->nonvis(), false, false);
 636
 637       // Add the COPY reloc.
 638       ssym->set_needs_dynsym_entry();
 639       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 640       rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
 641     }
 642 }
 643
 644 // Optimize the TLS relocation type based on what we know about the
 645 // symbol.  IS_FINAL is true if the final address of this symbol is
 646 // known at link time.
 647
 648 unsigned int
 649 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 650 {
 651   // If we are generating a shared library, then we can't do anything
 652   // in the linker.
 653   if (parameters->output_is_shared())
 654     return r_type;
 655
 656   switch (r_type)
 657     {
 658     case elfcpp::R_386_TLS_GD:
 659     case elfcpp::R_386_TLS_GOTDESC:
 660     case elfcpp::R_386_TLS_DESC_CALL:
 661       // These are Global-Dynamic which permits fully general TLS
 662       // access.  Since we know that we are generating an executable,
 663       // we can convert this to Initial-Exec.  If we also know that
 664       // this is a local symbol, we can further switch to Local-Exec.
 665       if (is_final)
 666         return elfcpp::R_386_TLS_LE_32;
 667       return elfcpp::R_386_TLS_IE_32;
 668
 669     case elfcpp::R_386_TLS_LDM:
 670       // This is Local-Dynamic, which refers to a local symbol in the
 671       // dynamic TLS block.  Since we know that we generating an
 672       // executable, we can switch to Local-Exec.
 673       return elfcpp::R_386_TLS_LE_32;
 674
 675     case elfcpp::R_386_TLS_LDO_32:
 676       // Another type of Local-Dynamic relocation.
 677       return elfcpp::R_386_TLS_LE;
 678
 679     case elfcpp::R_386_TLS_IE:
 680     case elfcpp::R_386_TLS_GOTIE:
 681     case elfcpp::R_386_TLS_IE_32:
 682       // These are Initial-Exec relocs which get the thread offset
 683       // from the GOT.  If we know that we are linking against the
 684       // local symbol, we can switch to Local-Exec, which links the
 685       // thread offset into the instruction.
 686       if (is_final)
 687         return elfcpp::R_386_TLS_LE_32;
 688       return r_type;
 689
 690     case elfcpp::R_386_TLS_LE:
 691     case elfcpp::R_386_TLS_LE_32:
 692       // When we already have Local-Exec, there is nothing further we
 693       // can do.
 694       return r_type;
 695
 696     default:
 697       gold_unreachable();
 698     }
 699 }
 700
 701 // Scan a relocation for a local symbol.
 702
 703 inline void
 704 Target_i386::Scan::local(const General_options&,
 705                          Symbol_table* symtab,
 706                          Layout* layout,
 707                          Target_i386* target,
 708                          Sized_relobj<32, false>* object,
 709                          unsigned int,
 710                          const elfcpp::Rel<32, false>&,
 711                          unsigned int r_type,
 712                          const elfcpp::Sym<32, false>&)
 713 {
 714   switch (r_type)
 715     {
 716     case elfcpp::R_386_NONE:
 717     case elfcpp::R_386_GNU_VTINHERIT:
 718     case elfcpp::R_386_GNU_VTENTRY:
 719       break;
 720
 721     case elfcpp::R_386_32:
 722     case elfcpp::R_386_16:
 723     case elfcpp::R_386_8:
 724       // FIXME: If we are generating a shared object we need to copy
 725       // this relocation into the object.
 726       gold_assert(!parameters->output_is_shared());
 727       break;
 728
 729     case elfcpp::R_386_PC32:
 730     case elfcpp::R_386_PC16:
 731     case elfcpp::R_386_PC8:
 732       break;
 733
 734     case elfcpp::R_386_GOTOFF:
 735     case elfcpp::R_386_GOTPC:
 736       // We need a GOT section.
 737       target->got_section(symtab, layout);
 738       break;
 739
 740     case elfcpp::R_386_COPY:
 741     case elfcpp::R_386_GLOB_DAT:
 742     case elfcpp::R_386_JUMP_SLOT:
 743     case elfcpp::R_386_RELATIVE:
 744       // These are outstanding tls relocs, which are unexpected when
 745       // linking.
 746     case elfcpp::R_386_TLS_TPOFF:
 747     case elfcpp::R_386_TLS_DTPMOD32:
 748     case elfcpp::R_386_TLS_DTPOFF32:
 749     case elfcpp::R_386_TLS_TPOFF32:
 750     case elfcpp::R_386_TLS_DESC:
 751       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 752               program_name, object->name().c_str(), r_type);
 753       gold_exit(false);
 754       break;
 755
 756       // These are initial tls relocs, which are expected when
 757       // linking.
 758     case elfcpp::R_386_TLS_IE:
 759     case elfcpp::R_386_TLS_GOTIE:
 760     case elfcpp::R_386_TLS_LE:
 761     case elfcpp::R_386_TLS_GD:
 762     case elfcpp::R_386_TLS_LDM:
 763     case elfcpp::R_386_TLS_LDO_32:
 764     case elfcpp::R_386_TLS_IE_32:
 765     case elfcpp::R_386_TLS_LE_32:
 766     case elfcpp::R_386_TLS_GOTDESC:
 767     case elfcpp::R_386_TLS_DESC_CALL:
 768       {
 769         bool output_is_shared = parameters->output_is_shared();
 770         r_type = Target_i386::optimize_tls_reloc(!output_is_shared,
 771                                                  r_type);
 772         switch (r_type)
 773           {
 774           case elfcpp::R_386_TLS_LE:
 775           case elfcpp::R_386_TLS_LE_32:
 776             // FIXME: If generating a shared object, we need to copy
 777             // this relocation into the object.
 778             gold_assert(!output_is_shared);
 779             break;
 780
 781           case elfcpp::R_386_TLS_IE:
 782           case elfcpp::R_386_TLS_GOTIE:
 783           case elfcpp::R_386_TLS_GD:
 784           case elfcpp::R_386_TLS_LDM:
 785           case elfcpp::R_386_TLS_LDO_32:
 786           case elfcpp::R_386_TLS_IE_32:
 787           case elfcpp::R_386_TLS_GOTDESC:
 788           case elfcpp::R_386_TLS_DESC_CALL:
 789             fprintf(stderr,
 790                     _("%s: %s: unsupported reloc %u against local symbol\n"),
 791                     program_name, object->name().c_str(), r_type);
 792             break;
 793           }
 794       }
 795       break;
 796
 797     case elfcpp::R_386_GOT32:
 798     case elfcpp::R_386_PLT32:
 799     case elfcpp::R_386_32PLT:
 800     case elfcpp::R_386_TLS_GD_32:
 801     case elfcpp::R_386_TLS_GD_PUSH:
 802     case elfcpp::R_386_TLS_GD_CALL:
 803     case elfcpp::R_386_TLS_GD_POP:
 804     case elfcpp::R_386_TLS_LDM_32:
 805     case elfcpp::R_386_TLS_LDM_PUSH:
 806     case elfcpp::R_386_TLS_LDM_CALL:
 807     case elfcpp::R_386_TLS_LDM_POP:
 808     case elfcpp::R_386_USED_BY_INTEL_200:
 809     default:
 810       fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"),
 811               program_name, object->name().c_str(), r_type);
 812       break;
 813     }
 814 }
 815
 816 // Scan a relocation for a global symbol.
 817
 818 inline void
 819 Target_i386::Scan::global(const General_options& options,
 820                           Symbol_table* symtab,
 821                           Layout* layout,
 822                           Target_i386* target,
 823                           Sized_relobj<32, false>* object,
 824                           unsigned int data_shndx,
 825                           const elfcpp::Rel<32, false>& reloc,
 826                           unsigned int r_type,
 827                           Symbol* gsym)
 828 {
 829   switch (r_type)
 830     {
 831     case elfcpp::R_386_NONE:
 832     case elfcpp::R_386_GNU_VTINHERIT:
 833     case elfcpp::R_386_GNU_VTENTRY:
 834       break;
 835
 836     case elfcpp::R_386_32:
 837     case elfcpp::R_386_PC32:
 838     case elfcpp::R_386_16:
 839     case elfcpp::R_386_PC16:
 840     case elfcpp::R_386_8:
 841     case elfcpp::R_386_PC8:
 842       // FIXME: If we are generating a shared object we may need to
 843       // copy this relocation into the object.  If this symbol is
 844       // defined in a shared object, we may need to copy this
 845       // relocation in order to avoid a COPY relocation.
 846       gold_assert(!parameters->output_is_shared());
 847
 848       if (gsym->is_from_dynobj())
 849         {
 850           // This symbol is defined in a dynamic object.  If it is a
 851           // function, we make a PLT entry.  Otherwise we need to
 852           // either generate a COPY reloc or copy this reloc.
 853           if (gsym->type() == elfcpp::STT_FUNC)
 854             {
 855               target->make_plt_entry(symtab, layout, gsym);
 856
 857               // If this is not a PC relative reference, then we may
 858               // be taking the address of the function.  In that case
 859               // we need to set the entry in the dynamic symbol table
 860               // to the address of the PLT entry.
 861               if (r_type != elfcpp::R_386_PC32
 862                   && r_type != elfcpp::R_386_PC16
 863                   && r_type != elfcpp::R_386_PC8)
 864                 gsym->set_needs_dynsym_value();
 865             }
 866           else
 867             target->copy_reloc(&options, symtab, layout, object, data_shndx,
 868                                gsym, reloc);
 869         }
 870
 871       break;
 872
 873     case elfcpp::R_386_GOT32:
 874       {
 875         // The symbol requires a GOT entry.
 876         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 877         if (got->add_global(gsym))
 878           {
 879             // If this symbol is not fully resolved, we need to add a
 880             // dynamic relocation for it.
 881             if (!gsym->final_value_is_known())
 882               {
 883                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 884                 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
 885                                     gsym->got_offset());
 886               }
 887           }
 888       }
 889       break;
 890
 891     case elfcpp::R_386_PLT32:
 892       // If the symbol is fully resolved, this is just a PC32 reloc.
 893       // Otherwise we need a PLT entry.
 894       if (gsym->final_value_is_known())
 895         break;
 896       target->make_plt_entry(symtab, layout, gsym);
 897       break;
 898
 899     case elfcpp::R_386_GOTOFF:
 900     case elfcpp::R_386_GOTPC:
 901       // We need a GOT section.
 902       target->got_section(symtab, layout);
 903       break;
 904
 905     case elfcpp::R_386_COPY:
 906     case elfcpp::R_386_GLOB_DAT:
 907     case elfcpp::R_386_JUMP_SLOT:
 908     case elfcpp::R_386_RELATIVE:
 909       // These are outstanding tls relocs, which are unexpected when
 910       // linking.
 911     case elfcpp::R_386_TLS_TPOFF:
 912     case elfcpp::R_386_TLS_DTPMOD32:
 913     case elfcpp::R_386_TLS_DTPOFF32:
 914     case elfcpp::R_386_TLS_TPOFF32:
 915     case elfcpp::R_386_TLS_DESC:
 916       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 917               program_name, object->name().c_str(), r_type);
 918       gold_exit(false);
 919       break;
 920
 921       // These are initial tls relocs, which are expected when
 922       // linking.
 923     case elfcpp::R_386_TLS_IE:
 924     case elfcpp::R_386_TLS_GOTIE:
 925     case elfcpp::R_386_TLS_LE:
 926     case elfcpp::R_386_TLS_GD:
 927     case elfcpp::R_386_TLS_LDM:
 928     case elfcpp::R_386_TLS_LDO_32:
 929     case elfcpp::R_386_TLS_IE_32:
 930     case elfcpp::R_386_TLS_LE_32:
 931     case elfcpp::R_386_TLS_GOTDESC:
 932     case elfcpp::R_386_TLS_DESC_CALL:
 933       {
 934         const bool is_final = gsym->final_value_is_known();
 935         r_type = Target_i386::optimize_tls_reloc(is_final, r_type);
 936         switch (r_type)
 937           {
 938           case elfcpp::R_386_TLS_LE:
 939           case elfcpp::R_386_TLS_LE_32:
 940             // FIXME: If generating a shared object, we need to copy
 941             // this relocation into the object.
 942             gold_assert(!parameters->output_is_shared());
 943             break;
 944
 945           case elfcpp::R_386_TLS_IE:
 946           case elfcpp::R_386_TLS_GOTIE:
 947           case elfcpp::R_386_TLS_GD:
 948           case elfcpp::R_386_TLS_LDM:
 949           case elfcpp::R_386_TLS_LDO_32:
 950           case elfcpp::R_386_TLS_IE_32:
 951           case elfcpp::R_386_TLS_GOTDESC:
 952           case elfcpp::R_386_TLS_DESC_CALL:
 953             fprintf(stderr,
 954                     _("%s: %s: unsupported reloc %u "
 955                       "against global symbol %s\n"),
 956                     program_name, object->name().c_str(), r_type,
 957                     gsym->name());
 958             break;
 959           }
 960       }
 961       break;
 962
 963     case elfcpp::R_386_32PLT:
 964     case elfcpp::R_386_TLS_GD_32:
 965     case elfcpp::R_386_TLS_GD_PUSH:
 966     case elfcpp::R_386_TLS_GD_CALL:
 967     case elfcpp::R_386_TLS_GD_POP:
 968     case elfcpp::R_386_TLS_LDM_32:
 969     case elfcpp::R_386_TLS_LDM_PUSH:
 970     case elfcpp::R_386_TLS_LDM_CALL:
 971     case elfcpp::R_386_TLS_LDM_POP:
 972     case elfcpp::R_386_USED_BY_INTEL_200:
 973     default:
 974       fprintf(stderr,
 975               _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 976               program_name, object->name().c_str(), r_type, gsym->name());
 977       break;
 978     }
 979 }
 980
 981 // Scan relocations for a section.
 982
 983 void
 984 Target_i386::scan_relocs(const General_options& options,
 985                          Symbol_table* symtab,
 986                          Layout* layout,
 987                          Sized_relobj<32, false>* object,
 988                          unsigned int data_shndx,
 989                          unsigned int sh_type,
 990                          const unsigned char* prelocs,
 991                          size_t reloc_count,
 992                          size_t local_symbol_count,
 993                          const unsigned char* plocal_symbols,
 994                          Symbol** global_symbols)
 995 {
 996   if (sh_type == elfcpp::SHT_RELA)
 997     {
 998       fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"),
 999               program_name, object->name().c_str());
1000       gold_exit(false);
1001     }
1002
1003   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1004                     Target_i386::Scan>(
1005     options,
1006     symtab,
1007     layout,
1008     this,
1009     object,
1010     data_shndx,
1011     prelocs,
1012     reloc_count,
1013     local_symbol_count,
1014     plocal_symbols,
1015     global_symbols);
1016 }
1017
1018 // Finalize the sections.
1019
1020 void
1021 Target_i386::do_finalize_sections(Layout* layout)
1022 {
1023   // Fill in some more dynamic tags.
1024   Output_data_dynamic* const odyn = layout->dynamic_data();
1025   if (odyn != NULL)
1026     {
1027       if (this->got_plt_ != NULL)
1028         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1029
1030       if (this->plt_ != NULL)
1031         {
1032           const Output_data* od = this->plt_->rel_plt();
1033           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1034           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1035           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1036         }
1037
1038       if (this->rel_dyn_ != NULL)
1039         {
1040           const Output_data* od = this->rel_dyn_;
1041           odyn->add_section_address(elfcpp::DT_REL, od);
1042           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1043           odyn->add_constant(elfcpp::DT_RELENT,
1044                              elfcpp::Elf_sizes<32>::rel_size);
1045         }
1046
1047       if (!parameters->output_is_shared())
1048         {
1049           // The value of the DT_DEBUG tag is filled in by the dynamic
1050           // linker at run time, and used by the debugger.
1051           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1052         }
1053     }
1054
1055   // Emit any relocs we saved in an attempt to avoid generating COPY
1056   // relocs.
1057   if (this->copy_relocs_ == NULL)
1058     return;
1059   if (this->copy_relocs_->any_to_emit())
1060     {
1061       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1062       this->copy_relocs_->emit(rel_dyn);
1063     }
1064   delete this->copy_relocs_;
1065   this->copy_relocs_ = NULL;
1066 }
1067
1068 // Perform a relocation.
1069
1070 inline bool
1071 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1072                                 Target_i386* target,
1073                                 size_t relnum,
1074                                 const elfcpp::Rel<32, false>& rel,
1075                                 unsigned int r_type,
1076                                 const Sized_symbol<32>* gsym,
1077                                 const Symbol_value<32>* psymval,
1078                                 unsigned char* view,
1079                                 elfcpp::Elf_types<32>::Elf_Addr address,
1080                                 off_t view_size)
1081 {
1082   if (this->skip_call_tls_get_addr_)
1083     {
1084       if (r_type != elfcpp::R_386_PLT32
1085           || gsym == NULL
1086           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1087         {
1088           fprintf(stderr, _("%s: %s: missing expected TLS relocation\n"),
1089                   program_name,
1090                   relinfo->location(relnum, rel.get_r_offset()).c_str());
1091           gold_exit(false);
1092         }
1093
1094       this->skip_call_tls_get_addr_ = false;
1095
1096       return false;
1097     }
1098
1099   // Pick the value to use for symbols defined in shared objects.
1100   Symbol_value<32> symval;
1101   if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset())
1102     {
1103       symval.set_output_value(target->plt_section()->address()
1104                               + gsym->plt_offset());
1105       psymval = &symval;
1106     }
1107
1108   const Sized_relobj<32, false>* object = relinfo->object;
1109
1110   switch (r_type)
1111     {
1112     case elfcpp::R_386_NONE:
1113     case elfcpp::R_386_GNU_VTINHERIT:
1114     case elfcpp::R_386_GNU_VTENTRY:
1115       break;
1116
1117     case elfcpp::R_386_32:
1118       Relocate_functions<32, false>::rel32(view, object, psymval);
1119       break;
1120
1121     case elfcpp::R_386_PC32:
1122       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1123       break;
1124
1125     case elfcpp::R_386_16:
1126       Relocate_functions<32, false>::rel16(view, object, psymval);
1127       break;
1128
1129     case elfcpp::R_386_PC16:
1130       Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1131       break;
1132
1133     case elfcpp::R_386_8:
1134       Relocate_functions<32, false>::rel8(view, object, psymval);
1135       break;
1136
1137     case elfcpp::R_386_PC8:
1138       Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1139       break;
1140
1141     case elfcpp::R_386_PLT32:
1142       gold_assert(gsym->has_plt_offset()
1143                   || gsym->final_value_is_known());
1144       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1145       break;
1146
1147     case elfcpp::R_386_GOT32:
1148       // Local GOT offsets not yet supported.
1149       gold_assert(gsym);
1150       gold_assert(gsym->has_got_offset());
1151       Relocate_functions<32, false>::rel32(view, gsym->got_offset());
1152       break;
1153
1154     case elfcpp::R_386_GOTOFF:
1155       {
1156         elfcpp::Elf_types<32>::Elf_Addr value;
1157         value = (psymval->value(object, 0)
1158                  - target->got_section(NULL, NULL)->address());
1159         Relocate_functions<32, false>::rel32(view, value);
1160       }
1161       break;
1162
1163     case elfcpp::R_386_GOTPC:
1164       {
1165         elfcpp::Elf_types<32>::Elf_Addr value;
1166         value = target->got_section(NULL, NULL)->address();
1167         Relocate_functions<32, false>::pcrel32(view, value, address);
1168       }
1169       break;
1170
1171     case elfcpp::R_386_COPY:
1172     case elfcpp::R_386_GLOB_DAT:
1173     case elfcpp::R_386_JUMP_SLOT:
1174     case elfcpp::R_386_RELATIVE:
1175       // These are outstanding tls relocs, which are unexpected when
1176       // linking.
1177     case elfcpp::R_386_TLS_TPOFF:
1178     case elfcpp::R_386_TLS_DTPMOD32:
1179     case elfcpp::R_386_TLS_DTPOFF32:
1180     case elfcpp::R_386_TLS_TPOFF32:
1181     case elfcpp::R_386_TLS_DESC:
1182       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
1183               program_name,
1184               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1185               r_type);
1186       gold_exit(false);
1187       break;
1188
1189       // These are initial tls relocs, which are expected when
1190       // linking.
1191     case elfcpp::R_386_TLS_IE:
1192     case elfcpp::R_386_TLS_GOTIE:
1193     case elfcpp::R_386_TLS_LE:
1194     case elfcpp::R_386_TLS_GD:
1195     case elfcpp::R_386_TLS_LDM:
1196     case elfcpp::R_386_TLS_LDO_32:
1197     case elfcpp::R_386_TLS_IE_32:
1198     case elfcpp::R_386_TLS_LE_32:
1199     case elfcpp::R_386_TLS_GOTDESC:
1200     case elfcpp::R_386_TLS_DESC_CALL:
1201       this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1202                          address, view_size);
1203       break;
1204
1205     case elfcpp::R_386_32PLT:
1206     case elfcpp::R_386_TLS_GD_32:
1207     case elfcpp::R_386_TLS_GD_PUSH:
1208     case elfcpp::R_386_TLS_GD_CALL:
1209     case elfcpp::R_386_TLS_GD_POP:
1210     case elfcpp::R_386_TLS_LDM_32:
1211     case elfcpp::R_386_TLS_LDM_PUSH:
1212     case elfcpp::R_386_TLS_LDM_CALL:
1213     case elfcpp::R_386_TLS_LDM_POP:
1214     case elfcpp::R_386_USED_BY_INTEL_200:
1215     default:
1216       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1217               program_name,
1218               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1219               r_type);
1220       // gold_exit(false);
1221       break;
1222     }
1223
1224   return true;
1225 }
1226
1227 // Perform a TLS relocation.
1228
1229 inline void
1230 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1231                                     size_t relnum,
1232                                     const elfcpp::Rel<32, false>& rel,
1233                                     unsigned int r_type,
1234                                     const Sized_symbol<32>* gsym,
1235                                     const Symbol_value<32>* psymval,
1236                                     unsigned char* view,
1237                                     elfcpp::Elf_types<32>::Elf_Addr,
1238                                     off_t view_size)
1239 {
1240   Output_segment* tls_segment = relinfo->layout->tls_segment();
1241   if (tls_segment == NULL)
1242     {
1243       fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"),
1244               program_name,
1245               relinfo->location(relnum, rel.get_r_offset()).c_str());
1246       gold_exit(false);
1247     }
1248
1249   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1250
1251   const bool is_final = (gsym == NULL
1252                          ? !parameters->output_is_shared()
1253                          : gsym->final_value_is_known());
1254   const unsigned int opt_r_type =
1255     Target_i386::optimize_tls_reloc(is_final, r_type);
1256   switch (r_type)
1257     {
1258     case elfcpp::R_386_TLS_LE_32:
1259       value = tls_segment->vaddr() + tls_segment->memsz() - value;
1260       Relocate_functions<32, false>::rel32(view, value);
1261       break;
1262
1263     case elfcpp::R_386_TLS_LE:
1264       value = value - (tls_segment->vaddr() + tls_segment->memsz());
1265       Relocate_functions<32, false>::rel32(view, value);
1266       break;
1267
1268     case elfcpp::R_386_TLS_IE:
1269     case elfcpp::R_386_TLS_GOTIE:
1270     case elfcpp::R_386_TLS_IE_32:
1271       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1272         {
1273           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1274                                               rel, r_type, value, view,
1275                                               view_size);
1276           break;
1277         }
1278       fprintf(stderr, _("%s: %s: unsupported reloc type %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     case elfcpp::R_386_TLS_GD:
1286       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
1287         {
1288           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1289                              rel, r_type, value, view,
1290                              view_size);
1291           break;
1292         }
1293       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1294               program_name,
1295               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1296               r_type);
1297       // gold_exit(false);
1298       break;
1299
1300     case elfcpp::R_386_TLS_LDM:
1301     case elfcpp::R_386_TLS_LDO_32:
1302     case elfcpp::R_386_TLS_GOTDESC:
1303     case elfcpp::R_386_TLS_DESC_CALL:
1304       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1305               program_name,
1306               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1307               r_type);
1308       // gold_exit(false);
1309       break;
1310     }
1311 }
1312
1313 // Do a relocation in which we convert a TLS Initial-Exec to a
1314 // Local-Exec.
1315
1316 inline void
1317 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1318                                     size_t relnum,
1319                                     Output_segment* tls_segment,
1320                                     const elfcpp::Rel<32, false>& rel,
1321                                     unsigned int r_type,
1322                                     elfcpp::Elf_types<32>::Elf_Addr value,
1323                                     unsigned char* view,
1324                                     off_t view_size)
1325 {
1326   // We have to actually change the instructions, which means that we
1327   // need to examine the opcodes to figure out which instruction we
1328   // are looking at.
1329   if (r_type == elfcpp::R_386_TLS_IE)
1330     {
1331       // movl %gs:XX,%eax  ==>  movl $YY,%eax
1332       // movl %gs:XX,%reg  ==>  movl $YY,%reg
1333       // addl %gs:XX,%reg  ==>  addl $YY,%reg
1334       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -1);
1335       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1336
1337       unsigned char op1 = view[-1];
1338       if (op1 == 0xa1)
1339         {
1340           // movl XX,%eax  ==>  movl $YY,%eax
1341           view[-1] = 0xb8;
1342         }
1343       else
1344         {
1345           Target_i386::Relocate::check_range(relinfo, relnum, rel,
1346                                              view_size, -2);
1347
1348           unsigned char op2 = view[-2];
1349           if (op2 == 0x8b)
1350             {
1351               // movl XX,%reg  ==>  movl $YY,%reg
1352               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1353                                                (op1 & 0xc7) == 0x05);
1354               view[-2] = 0xc7;
1355               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1356             }
1357           else if (op2 == 0x03)
1358             {
1359               // addl XX,%reg  ==>  addl $YY,%reg
1360               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1361                                                (op1 & 0xc7) == 0x05);
1362               view[-2] = 0x81;
1363               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1364             }
1365           else
1366             Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1367         }
1368     }
1369   else
1370     {
1371       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1372       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1373       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1374       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1375       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
1376
1377       unsigned char op1 = view[-1];
1378       unsigned char op2 = view[-2];
1379       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1380                                        (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1381       if (op2 == 0x8b)
1382         {
1383           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1384           view[-2] = 0xc7;
1385           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1386         }
1387       else if (op2 == 0x2b)
1388         {
1389           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1390           view[-2] = 0x81;
1391           view[-1] = 0xe8 | ((op1 >> 3) & 7);
1392         }
1393       else if (op2 == 0x03)
1394         {
1395           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1396           view[-2] = 0x81;
1397           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1398         }
1399       else
1400         Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
1401     }
1402
1403   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1404   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1405     value = - value;
1406
1407   Relocate_functions<32, false>::rel32(view, value);
1408 }
1409
1410 // Do a relocation in which we convert a TLS Global-Dynamic to a
1411 // Local-Exec.
1412
1413 inline void
1414 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1415                                     size_t relnum,
1416                                     Output_segment* tls_segment,
1417                                     const elfcpp::Rel<32, false>& rel,
1418                                     unsigned int,
1419                                     elfcpp::Elf_types<32>::Elf_Addr value,
1420                                     unsigned char* view,
1421                                     off_t view_size)
1422 {
1423   // leal foo(,%reg,1),%eax; call ___tls_get_addr
1424   //  ==> movl %gs,0,%eax; subl $foo@tpoff,%eax
1425   // leal foo(%reg),%eax; call ___tls_get_addr
1426   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1427
1428   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
1429   Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 9);
1430
1431   unsigned char op1 = view[-1];
1432   unsigned char op2 = view[-2];
1433
1434   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1435                                    op2 == 0x8d || op2 == 0x04);
1436   Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1437                                    view[4] == 0xe8);
1438
1439   int roff = 5;
1440
1441   if (op2 == 0x04)
1442     {
1443       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -3);
1444       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1445                                        view[-3] == 0x8d);
1446       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1447                                        ((op1 & 0xc7) == 0x05
1448                                         && op1 != (4 << 3)));
1449       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1450     }
1451   else
1452     {
1453       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
1454                                        (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1455       if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1456           && view[9] == 0x90)
1457         {
1458           // There is a trailing nop.  Use the size byte subl.
1459           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1460           roff = 6;
1461         }
1462       else
1463         {
1464           // Use the five byte subl.
1465           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1466         }
1467     }
1468
1469   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1470   Relocate_functions<32, false>::rel32(view + roff, value);
1471
1472   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1473   // We can skip it.
1474   this->skip_call_tls_get_addr_ = true;
1475 }
1476
1477 // Check the range for a TLS relocation.
1478
1479 inline void
1480 Target_i386::Relocate::check_range(const Relocate_info<32, false>* relinfo,
1481                                    size_t relnum,
1482                                    const elfcpp::Rel<32, false>& rel,
1483                                    off_t view_size, off_t off)
1484 {
1485   off_t offset = rel.get_r_offset() + off;
1486   if (offset < 0 || offset > view_size)
1487     {
1488       fprintf(stderr, _("%s: %s: TLS relocation out of range\n"),
1489               program_name,
1490               relinfo->location(relnum, rel.get_r_offset()).c_str());
1491       gold_exit(false);
1492     }
1493 }
1494
1495 // Check the validity of a TLS relocation.  This is like assert.
1496
1497 inline void
1498 Target_i386::Relocate::check_tls(const Relocate_info<32, false>* relinfo,
1499                                  size_t relnum,
1500                                  const elfcpp::Rel<32, false>& rel,
1501                                  bool valid)
1502 {
1503   if (!valid)
1504     {
1505       fprintf(stderr,
1506               _("%s: %s: TLS relocation against invalid instruction\n"),
1507               program_name,
1508               relinfo->location(relnum, rel.get_r_offset()).c_str());
1509       gold_exit(false);
1510     }
1511 }
1512
1513 // Relocate section data.
1514
1515 void
1516 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1517                               unsigned int sh_type,
1518                               const unsigned char* prelocs,
1519                               size_t reloc_count,
1520                               unsigned char* view,
1521                               elfcpp::Elf_types<32>::Elf_Addr address,
1522                               off_t view_size)
1523 {
1524   gold_assert(sh_type == elfcpp::SHT_REL);
1525
1526   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1527                          Target_i386::Relocate>(
1528     relinfo,
1529     this,
1530     prelocs,
1531     reloc_count,
1532     view,
1533     address,
1534     view_size);
1535 }
1536
1537 // Return the value to use for a dynamic which requires special
1538 // treatment.  This is how we support equality comparisons of function
1539 // pointers across shared library boundaries, as described in the
1540 // processor specific ABI supplement.
1541
1542 uint64_t
1543 Target_i386::do_dynsym_value(const Symbol* gsym) const
1544 {
1545   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1546   return this->plt_section()->address() + gsym->plt_offset();
1547 }
1548
1549 // Return a string used to fill a code section with nops to take up
1550 // the specified length.
1551
1552 std::string
1553 Target_i386::do_code_fill(off_t length)
1554 {
1555   if (length >= 16)
1556     {
1557       // Build a jmp instruction to skip over the bytes.
1558       unsigned char jmp[5];
1559       jmp[0] = 0xe9;
1560       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1561       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1562               + std::string(length - 5, '\0'));
1563     }
1564
1565   // Nop sequences of various lengths.
1566   const char nop1[1] = { 0x90 };                   // nop
1567   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1568   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1569   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1570   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1571                          0x00 };                   // leal 0(%esi,1),%esi
1572   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1573                          0x00, 0x00 };
1574   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1575                          0x00, 0x00, 0x00 };
1576   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1577                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1578   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1579                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1580                          0x00 };
1581   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1582                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1583                            0x00, 0x00 };
1584   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1585                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1586                            0x00, 0x00, 0x00 };
1587   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1588                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1589                            0x00, 0x00, 0x00, 0x00 };
1590   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1591                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1592                            0x27, 0x00, 0x00, 0x00,
1593                            0x00 };
1594   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1595                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1596                            0xbc, 0x27, 0x00, 0x00,
1597                            0x00, 0x00 };
1598   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1599                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1600                            0x90, 0x90, 0x90, 0x90,
1601                            0x90, 0x90, 0x90 };
1602
1603   const char* nops[16] = {
1604     NULL,
1605     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1606     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1607   };
1608
1609   return std::string(nops[length], length);
1610 }
1611
1612 // The selector for i386 object files.
1613
1614 class Target_selector_i386 : public Target_selector
1615 {
1616 public:
1617   Target_selector_i386()
1618     : Target_selector(elfcpp::EM_386, 32, false)
1619   { }
1620
1621   Target*
1622   recognize(int machine, int osabi, int abiversion);
1623
1624  private:
1625   Target_i386* target_;
1626 };
1627
1628 // Recognize an i386 object file when we already know that the machine
1629 // number is EM_386.
1630
1631 Target*
1632 Target_selector_i386::recognize(int, int, int)
1633 {
1634   if (this->target_ == NULL)
1635     this->target_ = new Target_i386();
1636   return this->target_;
1637 }
1638
1639 Target_selector_i386 target_selector_i386;
1640
1641 } // End anonymous namespace.