gold/i386.cc

   1 // i386.cc -- i386 target support for gold.
   2
   3 // Copyright 2006, 2007 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24
  25 #include <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "parameters.h"
  29 #include "reloc.h"
  30 #include "i386.h"
  31 #include "object.h"
  32 #include "symtab.h"
  33 #include "layout.h"
  34 #include "output.h"
  35 #include "target.h"
  36 #include "target-reloc.h"
  37 #include "target-select.h"
  38 #include "tls.h"
  39
  40 namespace
  41 {
  42
  43 using namespace gold;
  44
  45 class Output_data_plt_i386;
  46
  47 // The i386 target class.
  48
  49 class Target_i386 : public Sized_target<32, false>
  50 {
  51  public:
  52   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
  53
  54   Target_i386()
  55     : Sized_target<32, false>(&i386_info),
  56       got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
  57       copy_relocs_(NULL), dynbss_(NULL)
  58   { }
  59
  60   // Scan the relocations to look for symbol adjustments.
  61   void
  62   scan_relocs(const General_options& options,
  63               Symbol_table* symtab,
  64               Layout* layout,
  65               Sized_relobj<32, false>* object,
  66               unsigned int data_shndx,
  67               unsigned int sh_type,
  68               const unsigned char* prelocs,
  69               size_t reloc_count,
  70               size_t local_symbol_count,
  71               const unsigned char* plocal_symbols,
  72               Symbol** global_symbols);
  73
  74   // Finalize the sections.
  75   void
  76   do_finalize_sections(Layout*);
  77
  78   // Return the value to use for a dynamic which requires special
  79   // treatment.
  80   uint64_t
  81   do_dynsym_value(const Symbol*) const;
  82
  83   // Relocate a section.
  84   void
  85   relocate_section(const Relocate_info<32, false>*,
  86                    unsigned int sh_type,
  87                    const unsigned char* prelocs,
  88                    size_t reloc_count,
  89                    unsigned char* view,
  90                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  91                    off_t view_size);
  92
  93   // Return a string used to fill a code section with nops.
  94   std::string
  95   do_code_fill(off_t length);
  96
  97  private:
  98   // The class which scans relocations.
  99   struct Scan
 100   {
 101     inline void
 102     local(const General_options& options, Symbol_table* symtab,
 103           Layout* layout, Target_i386* target,
 104           Sized_relobj<32, false>* object,
 105           unsigned int data_shndx,
 106           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 107           const elfcpp::Sym<32, false>& lsym);
 108
 109     inline void
 110     global(const General_options& options, Symbol_table* symtab,
 111            Layout* layout, Target_i386* target,
 112            Sized_relobj<32, false>* object,
 113            unsigned int data_shndx,
 114            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 115            Symbol* gsym);
 116
 117     static void
 118     unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
 119
 120     static void
 121     unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
 122                              Symbol*);
 123   };
 124
 125   // The class which implements relocation.
 126   class Relocate
 127   {
 128    public:
 129     Relocate()
 130       : skip_call_tls_get_addr_(false),
 131         local_dynamic_type_(LOCAL_DYNAMIC_NONE)
 132     { }
 133
 134     ~Relocate()
 135     {
 136       if (this->skip_call_tls_get_addr_)
 137         {
 138           // FIXME: This needs to specify the location somehow.
 139           fprintf(stderr, _("%s: missing expected TLS relocation\n"),
 140                   program_name);
 141           gold_exit(false);
 142         }
 143     }
 144
 145     // Do a relocation.  Return false if the caller should not issue
 146     // any warnings about this relocation.
 147     inline bool
 148     relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
 149              const elfcpp::Rel<32, false>&,
 150              unsigned int r_type, const Sized_symbol<32>*,
 151              const Symbol_value<32>*,
 152              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 153              off_t);
 154
 155    private:
 156     // Do a TLS relocation.
 157     inline void
 158     relocate_tls(const Relocate_info<32, false>*, size_t relnum,
 159                  const elfcpp::Rel<32, false>&,
 160                  unsigned int r_type, const Sized_symbol<32>*,
 161                  const Symbol_value<32>*,
 162                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
 163
 164     // Do a TLS Initial-Exec to Local-Exec transition.
 165     static inline void
 166     tls_ie_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     // Do a TLS Global-Dynamic to Local-Exec transition.
 174     inline void
 175     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 176                  Output_segment* tls_segment,
 177                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 178                  elfcpp::Elf_types<32>::Elf_Addr value,
 179                  unsigned char* view,
 180                  off_t view_size);
 181
 182     // Do a TLS Local-Dynamic to Local-Exec transition.
 183     inline void
 184     tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
 185                  Output_segment* tls_segment,
 186                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 187                  elfcpp::Elf_types<32>::Elf_Addr value,
 188                  unsigned char* view,
 189                  off_t view_size);
 190
 191     // We need to keep track of which type of local dynamic relocation
 192     // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
 193     enum Local_dynamic_type
 194     {
 195       LOCAL_DYNAMIC_NONE,
 196       LOCAL_DYNAMIC_SUN,
 197       LOCAL_DYNAMIC_GNU
 198     };
 199
 200     // This is set if we should skip the next reloc, which should be a
 201     // PLT32 reloc against ___tls_get_addr.
 202     bool skip_call_tls_get_addr_;
 203     // The type of local dynamic relocation we have seen in the section
 204     // being relocated, if any.
 205     Local_dynamic_type local_dynamic_type_;
 206   };
 207
 208   // Adjust TLS relocation type based on the options and whether this
 209   // is a local symbol.
 210   static tls::Tls_optimization
 211   optimize_tls_reloc(bool is_final, int r_type);
 212
 213   // Get the GOT section, creating it if necessary.
 214   Output_data_got<32, false>*
 215   got_section(Symbol_table*, Layout*);
 216
 217   // Create a PLT entry for a global symbol.
 218   void
 219   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 220
 221   // Get the PLT section.
 222   const Output_data_plt_i386*
 223   plt_section() const
 224   {
 225     gold_assert(this->plt_ != NULL);
 226     return this->plt_;
 227   }
 228
 229   // Get the dynamic reloc section, creating it if necessary.
 230   Reloc_section*
 231   rel_dyn_section(Layout*);
 232
 233   // Copy a relocation against a global symbol.
 234   void
 235   copy_reloc(const General_options*, Symbol_table*, Layout*,
 236              Sized_relobj<32, false>*, unsigned int,
 237              Symbol*, const elfcpp::Rel<32, false>&);
 238
 239   // Information about this specific target which we pass to the
 240   // general Target structure.
 241   static const Target::Target_info i386_info;
 242
 243   // The GOT section.
 244   Output_data_got<32, false>* got_;
 245   // The PLT section.
 246   Output_data_plt_i386* plt_;
 247   // The GOT PLT section.
 248   Output_data_space* got_plt_;
 249   // The dynamic reloc section.
 250   Reloc_section* rel_dyn_;
 251   // Relocs saved to avoid a COPY reloc.
 252   Copy_relocs<32, false>* copy_relocs_;
 253   // Space for variables copied with a COPY reloc.
 254   Output_data_space* dynbss_;
 255 };
 256
 257 const Target::Target_info Target_i386::i386_info =
 258 {
 259   32,                   // size
 260   false,                // is_big_endian
 261   elfcpp::EM_386,       // machine_code
 262   false,                // has_make_symbol
 263   false,                // has_resolve
 264   true,                 // has_code_fill
 265   "/usr/lib/libc.so.1", // dynamic_linker
 266   0x08048000,           // text_segment_address
 267   0x1000,               // abi_pagesize
 268   0x1000                // common_pagesize
 269 };
 270
 271 // Get the GOT section, creating it if necessary.
 272
 273 Output_data_got<32, false>*
 274 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 275 {
 276   if (this->got_ == NULL)
 277     {
 278       gold_assert(symtab != NULL && layout != NULL);
 279
 280       this->got_ = new Output_data_got<32, false>();
 281
 282       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 283                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 284                                       this->got_);
 285
 286       // The old GNU linker creates a .got.plt section.  We just
 287       // create another set of data in the .got section.  Note that we
 288       // always create a PLT if we create a GOT, although the PLT
 289       // might be empty.
 290       this->got_plt_ = new Output_data_space(4);
 291       layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 292                                       elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
 293                                       this->got_plt_);
 294
 295       // The first three entries are reserved.
 296       this->got_plt_->set_space_size(3 * 4);
 297
 298       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 299       symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL,
 300                                     this->got_plt_,
 301                                     0, 0, elfcpp::STT_OBJECT,
 302                                     elfcpp::STB_LOCAL,
 303                                     elfcpp::STV_HIDDEN, 0,
 304                                     false, false);
 305     }
 306
 307   return this->got_;
 308 }
 309
 310 // Get the dynamic reloc section, creating it if necessary.
 311
 312 Target_i386::Reloc_section*
 313 Target_i386::rel_dyn_section(Layout* layout)
 314 {
 315   if (this->rel_dyn_ == NULL)
 316     {
 317       gold_assert(layout != NULL);
 318       this->rel_dyn_ = new Reloc_section();
 319       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 320                                       elfcpp::SHF_ALLOC, this->rel_dyn_);
 321     }
 322   return this->rel_dyn_;
 323 }
 324
 325 // A class to handle the PLT data.
 326
 327 class Output_data_plt_i386 : public Output_section_data
 328 {
 329  public:
 330   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 331
 332   Output_data_plt_i386(Layout*, Output_data_space*);
 333
 334   // Add an entry to the PLT.
 335   void
 336   add_entry(Symbol* gsym);
 337
 338   // Return the .rel.plt section data.
 339   const Reloc_section*
 340   rel_plt() const
 341   { return this->rel_; }
 342
 343  protected:
 344   void
 345   do_adjust_output_section(Output_section* os);
 346
 347  private:
 348   // The size of an entry in the PLT.
 349   static const int plt_entry_size = 16;
 350
 351   // The first entry in the PLT for an executable.
 352   static unsigned char exec_first_plt_entry[plt_entry_size];
 353
 354   // The first entry in the PLT for a shared object.
 355   static unsigned char dyn_first_plt_entry[plt_entry_size];
 356
 357   // Other entries in the PLT for an executable.
 358   static unsigned char exec_plt_entry[plt_entry_size];
 359
 360   // Other entries in the PLT for a shared object.
 361   static unsigned char dyn_plt_entry[plt_entry_size];
 362
 363   // Set the final size.
 364   void
 365   do_set_address(uint64_t, off_t)
 366   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 367
 368   // Write out the PLT data.
 369   void
 370   do_write(Output_file*);
 371
 372   // The reloc section.
 373   Reloc_section* rel_;
 374   // The .got.plt section.
 375   Output_data_space* got_plt_;
 376   // The number of PLT entries.
 377   unsigned int count_;
 378 };
 379
 380 // Create the PLT section.  The ordinary .got section is an argument,
 381 // since we need to refer to the start.  We also create our own .got
 382 // section just for PLT entries.
 383
 384 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 385                                            Output_data_space* got_plt)
 386   : Output_section_data(4), got_plt_(got_plt), count_(0)
 387 {
 388   this->rel_ = new Reloc_section();
 389   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 390                                   elfcpp::SHF_ALLOC, this->rel_);
 391 }
 392
 393 void
 394 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 395 {
 396   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 397   // linker, and so do we.
 398   os->set_entsize(4);
 399 }
 400
 401 // Add an entry to the PLT.
 402
 403 void
 404 Output_data_plt_i386::add_entry(Symbol* gsym)
 405 {
 406   gold_assert(!gsym->has_plt_offset());
 407
 408   // Note that when setting the PLT offset we skip the initial
 409   // reserved PLT entry.
 410   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 411
 412   ++this->count_;
 413
 414   off_t got_offset = this->got_plt_->data_size();
 415
 416   // Every PLT entry needs a GOT entry which points back to the PLT
 417   // entry (this will be changed by the dynamic linker, normally
 418   // lazily when the function is called).
 419   this->got_plt_->set_space_size(got_offset + 4);
 420
 421   // Every PLT entry needs a reloc.
 422   gsym->set_needs_dynsym_entry();
 423   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 424                          got_offset);
 425
 426   // Note that we don't need to save the symbol.  The contents of the
 427   // PLT are independent of which symbols are used.  The symbols only
 428   // appear in the relocations.
 429 }
 430
 431 // The first entry in the PLT for an executable.
 432
 433 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 434 {
 435   0xff, 0x35,   // pushl contents of memory address
 436   0, 0, 0, 0,   // replaced with address of .got + 4
 437   0xff, 0x25,   // jmp indirect
 438   0, 0, 0, 0,   // replaced with address of .got + 8
 439   0, 0, 0, 0    // unused
 440 };
 441
 442 // The first entry in the PLT for a shared object.
 443
 444 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 445 {
 446   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 447   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 448   0, 0, 0, 0                    // unused
 449 };
 450
 451 // Subsequent entries in the PLT for an executable.
 452
 453 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 454 {
 455   0xff, 0x25,   // jmp indirect
 456   0, 0, 0, 0,   // replaced with address of symbol in .got
 457   0x68,         // pushl immediate
 458   0, 0, 0, 0,   // replaced with offset into relocation table
 459   0xe9,         // jmp relative
 460   0, 0, 0, 0    // replaced with offset to start of .plt
 461 };
 462
 463 // Subsequent entries in the PLT for a shared object.
 464
 465 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 466 {
 467   0xff, 0xa3,   // jmp *offset(%ebx)
 468   0, 0, 0, 0,   // replaced with offset of symbol in .got
 469   0x68,         // pushl immediate
 470   0, 0, 0, 0,   // replaced with offset into relocation table
 471   0xe9,         // jmp relative
 472   0, 0, 0, 0    // replaced with offset to start of .plt
 473 };
 474
 475 // Write out the PLT.  This uses the hand-coded instructions above,
 476 // and adjusts them as needed.  This is all specified by the i386 ELF
 477 // Processor Supplement.
 478
 479 void
 480 Output_data_plt_i386::do_write(Output_file* of)
 481 {
 482   const off_t offset = this->offset();
 483   const off_t oview_size = this->data_size();
 484   unsigned char* const oview = of->get_output_view(offset, oview_size);
 485
 486   const off_t got_file_offset = this->got_plt_->offset();
 487   const off_t got_size = this->got_plt_->data_size();
 488   unsigned char* const got_view = of->get_output_view(got_file_offset,
 489                                                       got_size);
 490
 491   unsigned char* pov = oview;
 492
 493   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 494   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 495
 496   if (parameters->output_is_shared())
 497     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 498   else
 499     {
 500       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 501       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 502       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 503     }
 504   pov += plt_entry_size;
 505
 506   unsigned char* got_pov = got_view;
 507
 508   memset(got_pov, 0, 12);
 509   got_pov += 12;
 510
 511   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 512
 513   unsigned int plt_offset = plt_entry_size;
 514   unsigned int plt_rel_offset = 0;
 515   unsigned int got_offset = 12;
 516   const unsigned int count = this->count_;
 517   for (unsigned int i = 0;
 518        i < count;
 519        ++i,
 520          pov += plt_entry_size,
 521          got_pov += 4,
 522          plt_offset += plt_entry_size,
 523          plt_rel_offset += rel_size,
 524          got_offset += 4)
 525     {
 526       // Set and adjust the PLT entry itself.
 527
 528       if (parameters->output_is_shared())
 529         {
 530           memcpy(pov, dyn_plt_entry, plt_entry_size);
 531           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 532         }
 533       else
 534         {
 535           memcpy(pov, exec_plt_entry, plt_entry_size);
 536           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 537                                                       (got_address
 538                                                        + got_offset));
 539         }
 540
 541       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 542       elfcpp::Swap<32, false>::writeval(pov + 12,
 543                                         - (plt_offset + plt_entry_size));
 544
 545       // Set the entry in the GOT.
 546       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 547     }
 548
 549   gold_assert(pov - oview == oview_size);
 550   gold_assert(got_pov - got_view == got_size);
 551
 552   of->write_output_view(offset, oview_size, oview);
 553   of->write_output_view(got_file_offset, got_size, got_view);
 554 }
 555
 556 // Create a PLT entry for a global symbol.
 557
 558 void
 559 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 560 {
 561   if (gsym->has_plt_offset())
 562     return;
 563
 564   if (this->plt_ == NULL)
 565     {
 566       // Create the GOT sections first.
 567       this->got_section(symtab, layout);
 568
 569       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 570       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 571                                       (elfcpp::SHF_ALLOC
 572                                        | elfcpp::SHF_EXECINSTR),
 573                                       this->plt_);
 574     }
 575
 576   this->plt_->add_entry(gsym);
 577 }
 578
 579 // Handle a relocation against a non-function symbol defined in a
 580 // dynamic object.  The traditional way to handle this is to generate
 581 // a COPY relocation to copy the variable at runtime from the shared
 582 // object into the executable's data segment.  However, this is
 583 // undesirable in general, as if the size of the object changes in the
 584 // dynamic object, the executable will no longer work correctly.  If
 585 // this relocation is in a writable section, then we can create a
 586 // dynamic reloc and the dynamic linker will resolve it to the correct
 587 // address at runtime.  However, we do not want do that if the
 588 // relocation is in a read-only section, as it would prevent the
 589 // readonly segment from being shared.  And if we have to eventually
 590 // generate a COPY reloc, then any dynamic relocations will be
 591 // useless.  So this means that if this is a writable section, we need
 592 // to save the relocation until we see whether we have to create a
 593 // COPY relocation for this symbol for any other relocation.
 594
 595 void
 596 Target_i386::copy_reloc(const General_options* options,
 597                         Symbol_table* symtab,
 598                         Layout* layout,
 599                         Sized_relobj<32, false>* object,
 600                         unsigned int data_shndx, Symbol* gsym,
 601                         const elfcpp::Rel<32, false>& rel)
 602 {
 603   Sized_symbol<32>* ssym;
 604   ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
 605                                                         SELECT_SIZE(32));
 606
 607   if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
 608                                                data_shndx, ssym))
 609     {
 610       // So far we do not need a COPY reloc.  Save this relocation.
 611       // If it turns out that we never need a COPY reloc for this
 612       // symbol, then we will emit the relocation.
 613       if (this->copy_relocs_ == NULL)
 614         this->copy_relocs_ = new Copy_relocs<32, false>();
 615       this->copy_relocs_->save(ssym, object, data_shndx, rel);
 616     }
 617   else
 618     {
 619       // Allocate space for this symbol in the .bss section.
 620
 621       elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
 622
 623       // There is no defined way to determine the required alignment
 624       // of the symbol.  We pick the alignment based on the size.  We
 625       // set an arbitrary maximum of 256.
 626       unsigned int align;
 627       for (align = 1; align < 512; align <<= 1)
 628         if ((symsize & align) != 0)
 629           break;
 630
 631       if (this->dynbss_ == NULL)
 632         {
 633           this->dynbss_ = new Output_data_space(align);
 634           layout->add_output_section_data(".bss",
 635                                           elfcpp::SHT_NOBITS,
 636                                           (elfcpp::SHF_ALLOC
 637                                            | elfcpp::SHF_WRITE),
 638                                           this->dynbss_);
 639         }
 640
 641       Output_data_space* dynbss = this->dynbss_;
 642
 643       if (align > dynbss->addralign())
 644         dynbss->set_space_alignment(align);
 645
 646       off_t dynbss_size = dynbss->data_size();
 647       dynbss_size = align_address(dynbss_size, align);
 648       off_t offset = dynbss_size;
 649       dynbss->set_space_size(dynbss_size + symsize);
 650
 651       // Define the symbol in the .dynbss section.
 652       symtab->define_in_output_data(this, ssym->name(), ssym->version(),
 653                                     dynbss, offset, symsize, ssym->type(),
 654                                     ssym->binding(), ssym->visibility(),
 655                                     ssym->nonvis(), false, false);
 656
 657       // Add the COPY reloc.
 658       ssym->set_needs_dynsym_entry();
 659       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 660       rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
 661     }
 662 }
 663
 664 // Optimize the TLS relocation type based on what we know about the
 665 // symbol.  IS_FINAL is true if the final address of this symbol is
 666 // known at link time.
 667
 668 tls::Tls_optimization
 669 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 670 {
 671   // If we are generating a shared library, then we can't do anything
 672   // in the linker.
 673   if (parameters->output_is_shared())
 674     return tls::TLSOPT_NONE;
 675
 676   switch (r_type)
 677     {
 678     case elfcpp::R_386_TLS_GD:
 679     case elfcpp::R_386_TLS_GOTDESC:
 680     case elfcpp::R_386_TLS_DESC_CALL:
 681       // These are Global-Dynamic which permits fully general TLS
 682       // access.  Since we know that we are generating an executable,
 683       // we can convert this to Initial-Exec.  If we also know that
 684       // this is a local symbol, we can further switch to Local-Exec.
 685       if (is_final)
 686         return tls::TLSOPT_TO_LE;
 687       return tls::TLSOPT_TO_IE;
 688
 689     case elfcpp::R_386_TLS_LDM:
 690       // This is Local-Dynamic, which refers to a local symbol in the
 691       // dynamic TLS block.  Since we know that we generating an
 692       // executable, we can switch to Local-Exec.
 693       return tls::TLSOPT_TO_LE;
 694
 695     case elfcpp::R_386_TLS_LDO_32:
 696       // Another type of Local-Dynamic relocation.
 697       return tls::TLSOPT_TO_LE;
 698
 699     case elfcpp::R_386_TLS_IE:
 700     case elfcpp::R_386_TLS_GOTIE:
 701     case elfcpp::R_386_TLS_IE_32:
 702       // These are Initial-Exec relocs which get the thread offset
 703       // from the GOT.  If we know that we are linking against the
 704       // local symbol, we can switch to Local-Exec, which links the
 705       // thread offset into the instruction.
 706       if (is_final)
 707         return tls::TLSOPT_TO_LE;
 708       return tls::TLSOPT_NONE;
 709
 710     case elfcpp::R_386_TLS_LE:
 711     case elfcpp::R_386_TLS_LE_32:
 712       // When we already have Local-Exec, there is nothing further we
 713       // can do.
 714       return tls::TLSOPT_NONE;
 715
 716     default:
 717       gold_unreachable();
 718     }
 719 }
 720
 721 // Report an unsupported relocation against a local symbol.
 722
 723 void
 724 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
 725                                            unsigned int r_type)
 726 {
 727   fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"),
 728           program_name, object->name().c_str(), r_type);
 729 }
 730
 731 // Scan a relocation for a local symbol.
 732
 733 inline void
 734 Target_i386::Scan::local(const General_options&,
 735                          Symbol_table* symtab,
 736                          Layout* layout,
 737                          Target_i386* target,
 738                          Sized_relobj<32, false>* object,
 739                          unsigned int,
 740                          const elfcpp::Rel<32, false>&,
 741                          unsigned int r_type,
 742                          const elfcpp::Sym<32, false>&)
 743 {
 744   switch (r_type)
 745     {
 746     case elfcpp::R_386_NONE:
 747     case elfcpp::R_386_GNU_VTINHERIT:
 748     case elfcpp::R_386_GNU_VTENTRY:
 749       break;
 750
 751     case elfcpp::R_386_32:
 752     case elfcpp::R_386_16:
 753     case elfcpp::R_386_8:
 754       // FIXME: If we are generating a shared object we need to copy
 755       // this relocation into the object.
 756       gold_assert(!parameters->output_is_shared());
 757       break;
 758
 759     case elfcpp::R_386_PC32:
 760     case elfcpp::R_386_PC16:
 761     case elfcpp::R_386_PC8:
 762       break;
 763
 764     case elfcpp::R_386_GOTOFF:
 765     case elfcpp::R_386_GOTPC:
 766       // We need a GOT section.
 767       target->got_section(symtab, layout);
 768       break;
 769
 770       // These are relocations which should only be seen by the
 771       // dynamic linker, and should never be seen here.
 772     case elfcpp::R_386_COPY:
 773     case elfcpp::R_386_GLOB_DAT:
 774     case elfcpp::R_386_JUMP_SLOT:
 775     case elfcpp::R_386_RELATIVE:
 776     case elfcpp::R_386_TLS_TPOFF:
 777     case elfcpp::R_386_TLS_DTPMOD32:
 778     case elfcpp::R_386_TLS_DTPOFF32:
 779     case elfcpp::R_386_TLS_TPOFF32:
 780     case elfcpp::R_386_TLS_DESC:
 781       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 782               program_name, object->name().c_str(), r_type);
 783       gold_exit(false);
 784       break;
 785
 786       // These are initial TLS relocs, which are expected when
 787       // linking.
 788     case elfcpp::R_386_TLS_IE:
 789     case elfcpp::R_386_TLS_GOTIE:
 790     case elfcpp::R_386_TLS_LE:
 791     case elfcpp::R_386_TLS_GD:
 792     case elfcpp::R_386_TLS_LDM:
 793     case elfcpp::R_386_TLS_LDO_32:
 794     case elfcpp::R_386_TLS_IE_32:
 795     case elfcpp::R_386_TLS_LE_32:
 796     case elfcpp::R_386_TLS_GOTDESC:
 797     case elfcpp::R_386_TLS_DESC_CALL:
 798       {
 799         bool output_is_shared = parameters->output_is_shared();
 800         const tls::Tls_optimization optimized_type
 801             = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
 802         switch (r_type)
 803           {
 804           case elfcpp::R_386_TLS_LE:
 805           case elfcpp::R_386_TLS_LE_32:
 806             // FIXME: If generating a shared object, we need to copy
 807             // this relocation into the object.
 808             gold_assert(!output_is_shared);
 809             break;
 810
 811           case elfcpp::R_386_TLS_IE:
 812           case elfcpp::R_386_TLS_IE_32:
 813           case elfcpp::R_386_TLS_GOTIE:
 814             // FIXME: If not relaxing to LE, we need to generate a
 815             // TPOFF or TPOFF32 reloc.
 816             if (optimized_type != tls::TLSOPT_TO_LE)
 817               unsupported_reloc_local(object, r_type);
 818             break;
 819
 820           case elfcpp::R_386_TLS_LDM:
 821             // FIXME: If not relaxing to LE, we need to generate a
 822             // DTPMOD32 reloc.
 823             if (optimized_type != tls::TLSOPT_TO_LE)
 824               unsupported_reloc_local(object, r_type);
 825             break;
 826
 827           case elfcpp::R_386_TLS_LDO_32:
 828             break;
 829
 830           case elfcpp::R_386_TLS_GD:
 831           case elfcpp::R_386_TLS_GOTDESC:
 832           case elfcpp::R_386_TLS_DESC_CALL:
 833             // FIXME: If not relaxing to LE, we need to generate
 834             // DTPMOD32 and DTPOFF32 relocs.
 835             if (optimized_type != tls::TLSOPT_TO_LE)
 836               unsupported_reloc_local(object, r_type);
 837             break;
 838
 839           default:
 840             gold_unreachable();
 841           }
 842       }
 843       break;
 844
 845     case elfcpp::R_386_GOT32:
 846     case elfcpp::R_386_PLT32:
 847     case elfcpp::R_386_32PLT:
 848     case elfcpp::R_386_TLS_GD_32:
 849     case elfcpp::R_386_TLS_GD_PUSH:
 850     case elfcpp::R_386_TLS_GD_CALL:
 851     case elfcpp::R_386_TLS_GD_POP:
 852     case elfcpp::R_386_TLS_LDM_32:
 853     case elfcpp::R_386_TLS_LDM_PUSH:
 854     case elfcpp::R_386_TLS_LDM_CALL:
 855     case elfcpp::R_386_TLS_LDM_POP:
 856     case elfcpp::R_386_USED_BY_INTEL_200:
 857     default:
 858       unsupported_reloc_local(object, r_type);
 859       break;
 860     }
 861 }
 862
 863 // Report an unsupported relocation against a global symbol.
 864
 865 void
 866 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
 867                                             unsigned int r_type,
 868                                             Symbol* gsym)
 869 {
 870   fprintf(stderr,
 871           _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 872           program_name, object->name().c_str(), r_type, gsym->name());
 873 }
 874
 875 // Scan a relocation for a global symbol.
 876
 877 inline void
 878 Target_i386::Scan::global(const General_options& options,
 879                           Symbol_table* symtab,
 880                           Layout* layout,
 881                           Target_i386* target,
 882                           Sized_relobj<32, false>* object,
 883                           unsigned int data_shndx,
 884                           const elfcpp::Rel<32, false>& reloc,
 885                           unsigned int r_type,
 886                           Symbol* gsym)
 887 {
 888   switch (r_type)
 889     {
 890     case elfcpp::R_386_NONE:
 891     case elfcpp::R_386_GNU_VTINHERIT:
 892     case elfcpp::R_386_GNU_VTENTRY:
 893       break;
 894
 895     case elfcpp::R_386_32:
 896     case elfcpp::R_386_PC32:
 897     case elfcpp::R_386_16:
 898     case elfcpp::R_386_PC16:
 899     case elfcpp::R_386_8:
 900     case elfcpp::R_386_PC8:
 901       // FIXME: If we are generating a shared object we may need to
 902       // copy this relocation into the object.  If this symbol is
 903       // defined in a shared object, we may need to copy this
 904       // relocation in order to avoid a COPY relocation.
 905       gold_assert(!parameters->output_is_shared());
 906
 907       if (gsym->is_from_dynobj())
 908         {
 909           // This symbol is defined in a dynamic object.  If it is a
 910           // function, we make a PLT entry.  Otherwise we need to
 911           // either generate a COPY reloc or copy this reloc.
 912           if (gsym->type() == elfcpp::STT_FUNC)
 913             {
 914               target->make_plt_entry(symtab, layout, gsym);
 915
 916               // If this is not a PC relative reference, then we may
 917               // be taking the address of the function.  In that case
 918               // we need to set the entry in the dynamic symbol table
 919               // to the address of the PLT entry.
 920               if (r_type != elfcpp::R_386_PC32
 921                   && r_type != elfcpp::R_386_PC16
 922                   && r_type != elfcpp::R_386_PC8)
 923                 gsym->set_needs_dynsym_value();
 924             }
 925           else
 926             target->copy_reloc(&options, symtab, layout, object, data_shndx,
 927                                gsym, reloc);
 928         }
 929
 930       break;
 931
 932     case elfcpp::R_386_GOT32:
 933       {
 934         // The symbol requires a GOT entry.
 935         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 936         if (got->add_global(gsym))
 937           {
 938             // If this symbol is not fully resolved, we need to add a
 939             // dynamic relocation for it.
 940             if (!gsym->final_value_is_known())
 941               {
 942                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 943                 rel_dyn->add_global(gsym, elfcpp::R_386_GLOB_DAT, got,
 944                                     gsym->got_offset());
 945               }
 946           }
 947       }
 948       break;
 949
 950     case elfcpp::R_386_PLT32:
 951       // If the symbol is fully resolved, this is just a PC32 reloc.
 952       // Otherwise we need a PLT entry.
 953       if (gsym->final_value_is_known())
 954         break;
 955       target->make_plt_entry(symtab, layout, gsym);
 956       break;
 957
 958     case elfcpp::R_386_GOTOFF:
 959     case elfcpp::R_386_GOTPC:
 960       // We need a GOT section.
 961       target->got_section(symtab, layout);
 962       break;
 963
 964       // These are relocations which should only be seen by the
 965       // dynamic linker, and should never be seen here.
 966     case elfcpp::R_386_COPY:
 967     case elfcpp::R_386_GLOB_DAT:
 968     case elfcpp::R_386_JUMP_SLOT:
 969     case elfcpp::R_386_RELATIVE:
 970     case elfcpp::R_386_TLS_TPOFF:
 971     case elfcpp::R_386_TLS_DTPMOD32:
 972     case elfcpp::R_386_TLS_DTPOFF32:
 973     case elfcpp::R_386_TLS_TPOFF32:
 974     case elfcpp::R_386_TLS_DESC:
 975       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 976               program_name, object->name().c_str(), r_type);
 977       gold_exit(false);
 978       break;
 979
 980       // These are initial tls relocs, which are expected when
 981       // linking.
 982     case elfcpp::R_386_TLS_IE:
 983     case elfcpp::R_386_TLS_GOTIE:
 984     case elfcpp::R_386_TLS_LE:
 985     case elfcpp::R_386_TLS_GD:
 986     case elfcpp::R_386_TLS_LDM:
 987     case elfcpp::R_386_TLS_LDO_32:
 988     case elfcpp::R_386_TLS_IE_32:
 989     case elfcpp::R_386_TLS_LE_32:
 990     case elfcpp::R_386_TLS_GOTDESC:
 991     case elfcpp::R_386_TLS_DESC_CALL:
 992       {
 993         const bool is_final = gsym->final_value_is_known();
 994         const tls::Tls_optimization optimized_type
 995             = Target_i386::optimize_tls_reloc(is_final, r_type);
 996         switch (r_type)
 997           {
 998           case elfcpp::R_386_TLS_LE:
 999           case elfcpp::R_386_TLS_LE_32:
1000             // FIXME: If generating a shared object, we need to copy
1001             // this relocation into the object.
1002             gold_assert(!parameters->output_is_shared());
1003             break;
1004
1005           case elfcpp::R_386_TLS_IE:
1006           case elfcpp::R_386_TLS_IE_32:
1007           case elfcpp::R_386_TLS_GOTIE:
1008             // FIXME: If not relaxing to LE, we need to generate a
1009             // TPOFF or TPOFF32 reloc.
1010             if (optimized_type != tls::TLSOPT_TO_LE)
1011               unsupported_reloc_global(object, r_type, gsym);
1012             break;
1013
1014           case elfcpp::R_386_TLS_LDM:
1015             // FIXME: If not relaxing to LE, we need to generate a
1016             // DTPMOD32 reloc.
1017             if (optimized_type != tls::TLSOPT_TO_LE)
1018               unsupported_reloc_global(object, r_type, gsym);
1019             break;
1020
1021           case elfcpp::R_386_TLS_LDO_32:
1022             break;
1023
1024           case elfcpp::R_386_TLS_GD:
1025           case elfcpp::R_386_TLS_GOTDESC:
1026           case elfcpp::R_386_TLS_DESC_CALL:
1027             // FIXME: If not relaxing to LE, we need to generate
1028             // DTPMOD32 and DTPOFF32 relocs.
1029             if (optimized_type != tls::TLSOPT_TO_LE)
1030               unsupported_reloc_global(object, r_type, gsym);
1031             break;
1032
1033           default:
1034             gold_unreachable();
1035           }
1036       }
1037       break;
1038
1039     case elfcpp::R_386_32PLT:
1040     case elfcpp::R_386_TLS_GD_32:
1041     case elfcpp::R_386_TLS_GD_PUSH:
1042     case elfcpp::R_386_TLS_GD_CALL:
1043     case elfcpp::R_386_TLS_GD_POP:
1044     case elfcpp::R_386_TLS_LDM_32:
1045     case elfcpp::R_386_TLS_LDM_PUSH:
1046     case elfcpp::R_386_TLS_LDM_CALL:
1047     case elfcpp::R_386_TLS_LDM_POP:
1048     case elfcpp::R_386_USED_BY_INTEL_200:
1049     default:
1050       unsupported_reloc_global(object, r_type, gsym);
1051       break;
1052     }
1053 }
1054
1055 // Scan relocations for a section.
1056
1057 void
1058 Target_i386::scan_relocs(const General_options& options,
1059                          Symbol_table* symtab,
1060                          Layout* layout,
1061                          Sized_relobj<32, false>* object,
1062                          unsigned int data_shndx,
1063                          unsigned int sh_type,
1064                          const unsigned char* prelocs,
1065                          size_t reloc_count,
1066                          size_t local_symbol_count,
1067                          const unsigned char* plocal_symbols,
1068                          Symbol** global_symbols)
1069 {
1070   if (sh_type == elfcpp::SHT_RELA)
1071     {
1072       fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"),
1073               program_name, object->name().c_str());
1074       gold_exit(false);
1075     }
1076
1077   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1078                     Target_i386::Scan>(
1079     options,
1080     symtab,
1081     layout,
1082     this,
1083     object,
1084     data_shndx,
1085     prelocs,
1086     reloc_count,
1087     local_symbol_count,
1088     plocal_symbols,
1089     global_symbols);
1090 }
1091
1092 // Finalize the sections.
1093
1094 void
1095 Target_i386::do_finalize_sections(Layout* layout)
1096 {
1097   // Fill in some more dynamic tags.
1098   Output_data_dynamic* const odyn = layout->dynamic_data();
1099   if (odyn != NULL)
1100     {
1101       if (this->got_plt_ != NULL)
1102         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1103
1104       if (this->plt_ != NULL)
1105         {
1106           const Output_data* od = this->plt_->rel_plt();
1107           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1108           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1109           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1110         }
1111
1112       if (this->rel_dyn_ != NULL)
1113         {
1114           const Output_data* od = this->rel_dyn_;
1115           odyn->add_section_address(elfcpp::DT_REL, od);
1116           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1117           odyn->add_constant(elfcpp::DT_RELENT,
1118                              elfcpp::Elf_sizes<32>::rel_size);
1119         }
1120
1121       if (!parameters->output_is_shared())
1122         {
1123           // The value of the DT_DEBUG tag is filled in by the dynamic
1124           // linker at run time, and used by the debugger.
1125           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1126         }
1127     }
1128
1129   // Emit any relocs we saved in an attempt to avoid generating COPY
1130   // relocs.
1131   if (this->copy_relocs_ == NULL)
1132     return;
1133   if (this->copy_relocs_->any_to_emit())
1134     {
1135       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
1136       this->copy_relocs_->emit(rel_dyn);
1137     }
1138   delete this->copy_relocs_;
1139   this->copy_relocs_ = NULL;
1140 }
1141
1142 // Perform a relocation.
1143
1144 inline bool
1145 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1146                                 Target_i386* target,
1147                                 size_t relnum,
1148                                 const elfcpp::Rel<32, false>& rel,
1149                                 unsigned int r_type,
1150                                 const Sized_symbol<32>* gsym,
1151                                 const Symbol_value<32>* psymval,
1152                                 unsigned char* view,
1153                                 elfcpp::Elf_types<32>::Elf_Addr address,
1154                                 off_t view_size)
1155 {
1156   if (this->skip_call_tls_get_addr_)
1157     {
1158       if (r_type != elfcpp::R_386_PLT32
1159           || gsym == NULL
1160           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1161         {
1162           fprintf(stderr, _("%s: %s: missing expected TLS relocation\n"),
1163                   program_name,
1164                   relinfo->location(relnum, rel.get_r_offset()).c_str());
1165           gold_exit(false);
1166         }
1167
1168       this->skip_call_tls_get_addr_ = false;
1169
1170       return false;
1171     }
1172
1173   // Pick the value to use for symbols defined in shared objects.
1174   Symbol_value<32> symval;
1175   if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset())
1176     {
1177       symval.set_output_value(target->plt_section()->address()
1178                               + gsym->plt_offset());
1179       psymval = &symval;
1180     }
1181
1182   const Sized_relobj<32, false>* object = relinfo->object;
1183
1184   switch (r_type)
1185     {
1186     case elfcpp::R_386_NONE:
1187     case elfcpp::R_386_GNU_VTINHERIT:
1188     case elfcpp::R_386_GNU_VTENTRY:
1189       break;
1190
1191     case elfcpp::R_386_32:
1192       Relocate_functions<32, false>::rel32(view, object, psymval);
1193       break;
1194
1195     case elfcpp::R_386_PC32:
1196       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1197       break;
1198
1199     case elfcpp::R_386_16:
1200       Relocate_functions<32, false>::rel16(view, object, psymval);
1201       break;
1202
1203     case elfcpp::R_386_PC16:
1204       Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1205       break;
1206
1207     case elfcpp::R_386_8:
1208       Relocate_functions<32, false>::rel8(view, object, psymval);
1209       break;
1210
1211     case elfcpp::R_386_PC8:
1212       Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1213       break;
1214
1215     case elfcpp::R_386_PLT32:
1216       gold_assert(gsym->has_plt_offset()
1217                   || gsym->final_value_is_known());
1218       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1219       break;
1220
1221     case elfcpp::R_386_GOT32:
1222       // Local GOT offsets not yet supported.
1223       gold_assert(gsym);
1224       gold_assert(gsym->has_got_offset());
1225       Relocate_functions<32, false>::rel32(view, gsym->got_offset());
1226       break;
1227
1228     case elfcpp::R_386_GOTOFF:
1229       {
1230         elfcpp::Elf_types<32>::Elf_Addr value;
1231         value = (psymval->value(object, 0)
1232                  - target->got_section(NULL, NULL)->address());
1233         Relocate_functions<32, false>::rel32(view, value);
1234       }
1235       break;
1236
1237     case elfcpp::R_386_GOTPC:
1238       {
1239         elfcpp::Elf_types<32>::Elf_Addr value;
1240         value = target->got_section(NULL, NULL)->address();
1241         Relocate_functions<32, false>::pcrel32(view, value, address);
1242       }
1243       break;
1244
1245     case elfcpp::R_386_COPY:
1246     case elfcpp::R_386_GLOB_DAT:
1247     case elfcpp::R_386_JUMP_SLOT:
1248     case elfcpp::R_386_RELATIVE:
1249       // These are outstanding tls relocs, which are unexpected when
1250       // linking.
1251     case elfcpp::R_386_TLS_TPOFF:
1252     case elfcpp::R_386_TLS_DTPMOD32:
1253     case elfcpp::R_386_TLS_DTPOFF32:
1254     case elfcpp::R_386_TLS_TPOFF32:
1255     case elfcpp::R_386_TLS_DESC:
1256       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
1257               program_name,
1258               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1259               r_type);
1260       gold_exit(false);
1261       break;
1262
1263       // These are initial tls relocs, which are expected when
1264       // linking.
1265     case elfcpp::R_386_TLS_IE:
1266     case elfcpp::R_386_TLS_GOTIE:
1267     case elfcpp::R_386_TLS_LE:
1268     case elfcpp::R_386_TLS_GD:
1269     case elfcpp::R_386_TLS_LDM:
1270     case elfcpp::R_386_TLS_LDO_32:
1271     case elfcpp::R_386_TLS_IE_32:
1272     case elfcpp::R_386_TLS_LE_32:
1273     case elfcpp::R_386_TLS_GOTDESC:
1274     case elfcpp::R_386_TLS_DESC_CALL:
1275       this->relocate_tls(relinfo, relnum, rel, r_type, gsym, psymval, view,
1276                          address, view_size);
1277       break;
1278
1279     case elfcpp::R_386_32PLT:
1280     case elfcpp::R_386_TLS_GD_32:
1281     case elfcpp::R_386_TLS_GD_PUSH:
1282     case elfcpp::R_386_TLS_GD_CALL:
1283     case elfcpp::R_386_TLS_GD_POP:
1284     case elfcpp::R_386_TLS_LDM_32:
1285     case elfcpp::R_386_TLS_LDM_PUSH:
1286     case elfcpp::R_386_TLS_LDM_CALL:
1287     case elfcpp::R_386_TLS_LDM_POP:
1288     case elfcpp::R_386_USED_BY_INTEL_200:
1289     default:
1290       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1291               program_name,
1292               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1293               r_type);
1294       // gold_exit(false);
1295       break;
1296     }
1297
1298   return true;
1299 }
1300
1301 // Perform a TLS relocation.
1302
1303 inline void
1304 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1305                                     size_t relnum,
1306                                     const elfcpp::Rel<32, false>& rel,
1307                                     unsigned int r_type,
1308                                     const Sized_symbol<32>* gsym,
1309                                     const Symbol_value<32>* psymval,
1310                                     unsigned char* view,
1311                                     elfcpp::Elf_types<32>::Elf_Addr,
1312                                     off_t view_size)
1313 {
1314   Output_segment* tls_segment = relinfo->layout->tls_segment();
1315   if (tls_segment == NULL)
1316     {
1317       fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"),
1318               program_name,
1319               relinfo->location(relnum, rel.get_r_offset()).c_str());
1320       gold_exit(false);
1321     }
1322
1323   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(relinfo->object, 0);
1324
1325   const bool is_final = (gsym == NULL
1326                          ? !parameters->output_is_shared()
1327                          : gsym->final_value_is_known());
1328   const tls::Tls_optimization optimized_type
1329       = Target_i386::optimize_tls_reloc(is_final, r_type);
1330   switch (r_type)
1331     {
1332     case elfcpp::R_386_TLS_LE_32:
1333       value = tls_segment->vaddr() + tls_segment->memsz() - value;
1334       Relocate_functions<32, false>::rel32(view, value);
1335       break;
1336
1337     case elfcpp::R_386_TLS_LE:
1338       value = value - (tls_segment->vaddr() + tls_segment->memsz());
1339       Relocate_functions<32, false>::rel32(view, value);
1340       break;
1341
1342     case elfcpp::R_386_TLS_IE:
1343     case elfcpp::R_386_TLS_GOTIE:
1344     case elfcpp::R_386_TLS_IE_32:
1345       if (optimized_type == tls::TLSOPT_TO_LE)
1346         {
1347           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
1348                                               rel, r_type, value, view,
1349                                               view_size);
1350           break;
1351         }
1352       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1353               program_name,
1354               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1355               r_type);
1356       // gold_exit(false);
1357       break;
1358
1359     case elfcpp::R_386_TLS_GD:
1360       if (optimized_type == tls::TLSOPT_TO_LE)
1361         {
1362           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1363                              rel, r_type, value, view,
1364                              view_size);
1365           break;
1366         }
1367       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1368               program_name,
1369               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1370               r_type);
1371       // gold_exit(false);
1372       break;
1373
1374     case elfcpp::R_386_TLS_LDM:
1375       if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1376         {
1377           fprintf(stderr,
1378                   _("%s: %s: both SUN and GNU model TLS relocations\n"),
1379                   program_name,
1380                   relinfo->location(relnum, rel.get_r_offset()).c_str());
1381           gold_exit(false);
1382         }
1383       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1384       if (optimized_type == tls::TLSOPT_TO_LE)
1385         {
1386           this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
1387                              value, view, view_size);
1388           break;
1389         }
1390       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1391               program_name,
1392               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1393               r_type);
1394       // gold_exit(false);
1395       break;
1396
1397     case elfcpp::R_386_TLS_LDO_32:
1398       // This reloc can appear in debugging sections, in which case we
1399       // won't see the TLS_LDM reloc.  The local_dynamic_type field
1400       // tells us this.
1401       if (optimized_type != tls::TLSOPT_TO_LE
1402           || this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
1403         value = value - tls_segment->vaddr();
1404       else if (this->local_dynamic_type_ == LOCAL_DYNAMIC_GNU)
1405         value = value - (tls_segment->vaddr() + tls_segment->memsz());
1406       else
1407         value = tls_segment->vaddr() + tls_segment->memsz() - value;
1408       Relocate_functions<32, false>::rel32(view, value);
1409       break;
1410
1411     case elfcpp::R_386_TLS_GOTDESC:
1412     case elfcpp::R_386_TLS_DESC_CALL:
1413       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
1414               program_name,
1415               relinfo->location(relnum, rel.get_r_offset()).c_str(),
1416               r_type);
1417       // gold_exit(false);
1418       break;
1419     }
1420 }
1421
1422 // Do a relocation in which we convert a TLS Initial-Exec to a
1423 // Local-Exec.
1424
1425 inline void
1426 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
1427                                     size_t relnum,
1428                                     Output_segment* tls_segment,
1429                                     const elfcpp::Rel<32, false>& rel,
1430                                     unsigned int r_type,
1431                                     elfcpp::Elf_types<32>::Elf_Addr value,
1432                                     unsigned char* view,
1433                                     off_t view_size)
1434 {
1435   // We have to actually change the instructions, which means that we
1436   // need to examine the opcodes to figure out which instruction we
1437   // are looking at.
1438   if (r_type == elfcpp::R_386_TLS_IE)
1439     {
1440       // movl %gs:XX,%eax  ==>  movl $YY,%eax
1441       // movl %gs:XX,%reg  ==>  movl $YY,%reg
1442       // addl %gs:XX,%reg  ==>  addl $YY,%reg
1443       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
1444       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1445
1446       unsigned char op1 = view[-1];
1447       if (op1 == 0xa1)
1448         {
1449           // movl XX,%eax  ==>  movl $YY,%eax
1450           view[-1] = 0xb8;
1451         }
1452       else
1453         {
1454           tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1455
1456           unsigned char op2 = view[-2];
1457           if (op2 == 0x8b)
1458             {
1459               // movl XX,%reg  ==>  movl $YY,%reg
1460               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1461                              (op1 & 0xc7) == 0x05);
1462               view[-2] = 0xc7;
1463               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1464             }
1465           else if (op2 == 0x03)
1466             {
1467               // addl XX,%reg  ==>  addl $YY,%reg
1468               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1469                              (op1 & 0xc7) == 0x05);
1470               view[-2] = 0x81;
1471               view[-1] = 0xc0 | ((op1 >> 3) & 7);
1472             }
1473           else
1474             tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1475         }
1476     }
1477   else
1478     {
1479       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1480       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1481       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1482       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1483       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
1484
1485       unsigned char op1 = view[-1];
1486       unsigned char op2 = view[-2];
1487       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1488                      (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
1489       if (op2 == 0x8b)
1490         {
1491           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
1492           view[-2] = 0xc7;
1493           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1494         }
1495       else if (op2 == 0x2b)
1496         {
1497           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
1498           view[-2] = 0x81;
1499           view[-1] = 0xe8 | ((op1 >> 3) & 7);
1500         }
1501       else if (op2 == 0x03)
1502         {
1503           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
1504           view[-2] = 0x81;
1505           view[-1] = 0xc0 | ((op1 >> 3) & 7);
1506         }
1507       else
1508         tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
1509     }
1510
1511   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1512   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
1513     value = - value;
1514
1515   Relocate_functions<32, false>::rel32(view, value);
1516 }
1517
1518 // Do a relocation in which we convert a TLS Global-Dynamic to a
1519 // Local-Exec.
1520
1521 inline void
1522 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
1523                                     size_t relnum,
1524                                     Output_segment* tls_segment,
1525                                     const elfcpp::Rel<32, false>& rel,
1526                                     unsigned int,
1527                                     elfcpp::Elf_types<32>::Elf_Addr value,
1528                                     unsigned char* view,
1529                                     off_t view_size)
1530 {
1531   // leal foo(,%reg,1),%eax; call ___tls_get_addr
1532   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1533   // leal foo(%reg),%eax; call ___tls_get_addr
1534   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
1535
1536   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1537   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1538
1539   unsigned char op1 = view[-1];
1540   unsigned char op2 = view[-2];
1541
1542   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1543                  op2 == 0x8d || op2 == 0x04);
1544   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1545
1546   int roff = 5;
1547
1548   if (op2 == 0x04)
1549     {
1550       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
1551       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
1552       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1553                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
1554       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1555     }
1556   else
1557     {
1558       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1559                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
1560       if (static_cast<off_t>(rel.get_r_offset() + 9) < view_size
1561           && view[9] == 0x90)
1562         {
1563           // There is a trailing nop.  Use the size byte subl.
1564           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
1565           roff = 6;
1566         }
1567       else
1568         {
1569           // Use the five byte subl.
1570           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
1571         }
1572     }
1573
1574   value = tls_segment->vaddr() + tls_segment->memsz() - value;
1575   Relocate_functions<32, false>::rel32(view + roff, value);
1576
1577   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1578   // We can skip it.
1579   this->skip_call_tls_get_addr_ = true;
1580 }
1581
1582 // Do a relocation in which we convert a TLS Local-Dynamic to a
1583 // Local-Exec.
1584
1585 inline void
1586 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
1587                                     size_t relnum,
1588                                     Output_segment*,
1589                                     const elfcpp::Rel<32, false>& rel,
1590                                     unsigned int,
1591                                     elfcpp::Elf_types<32>::Elf_Addr,
1592                                     unsigned char* view,
1593                                     off_t view_size)
1594 {
1595   // leal foo(%reg), %eax; call ___tls_get_addr
1596   // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
1597
1598   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
1599   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
1600
1601   // FIXME: Does this test really always pass?
1602   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
1603                  view[-2] == 0x8d && view[-1] == 0x83);
1604
1605   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
1606
1607   memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
1608
1609   // The next reloc should be a PLT32 reloc against __tls_get_addr.
1610   // We can skip it.
1611   this->skip_call_tls_get_addr_ = true;
1612 }
1613
1614 // Relocate section data.
1615
1616 void
1617 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
1618                               unsigned int sh_type,
1619                               const unsigned char* prelocs,
1620                               size_t reloc_count,
1621                               unsigned char* view,
1622                               elfcpp::Elf_types<32>::Elf_Addr address,
1623                               off_t view_size)
1624 {
1625   gold_assert(sh_type == elfcpp::SHT_REL);
1626
1627   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
1628                          Target_i386::Relocate>(
1629     relinfo,
1630     this,
1631     prelocs,
1632     reloc_count,
1633     view,
1634     address,
1635     view_size);
1636 }
1637
1638 // Return the value to use for a dynamic which requires special
1639 // treatment.  This is how we support equality comparisons of function
1640 // pointers across shared library boundaries, as described in the
1641 // processor specific ABI supplement.
1642
1643 uint64_t
1644 Target_i386::do_dynsym_value(const Symbol* gsym) const
1645 {
1646   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
1647   return this->plt_section()->address() + gsym->plt_offset();
1648 }
1649
1650 // Return a string used to fill a code section with nops to take up
1651 // the specified length.
1652
1653 std::string
1654 Target_i386::do_code_fill(off_t length)
1655 {
1656   if (length >= 16)
1657     {
1658       // Build a jmp instruction to skip over the bytes.
1659       unsigned char jmp[5];
1660       jmp[0] = 0xe9;
1661       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
1662       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
1663               + std::string(length - 5, '\0'));
1664     }
1665
1666   // Nop sequences of various lengths.
1667   const char nop1[1] = { 0x90 };                   // nop
1668   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
1669   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
1670   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
1671   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
1672                          0x00 };                   // leal 0(%esi,1),%esi
1673   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
1674                          0x00, 0x00 };
1675   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
1676                          0x00, 0x00, 0x00 };
1677   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
1678                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
1679   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
1680                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
1681                          0x00 };
1682   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
1683                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
1684                            0x00, 0x00 };
1685   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
1686                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
1687                            0x00, 0x00, 0x00 };
1688   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1689                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
1690                            0x00, 0x00, 0x00, 0x00 };
1691   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
1692                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
1693                            0x27, 0x00, 0x00, 0x00,
1694                            0x00 };
1695   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
1696                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
1697                            0xbc, 0x27, 0x00, 0x00,
1698                            0x00, 0x00 };
1699   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
1700                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
1701                            0x90, 0x90, 0x90, 0x90,
1702                            0x90, 0x90, 0x90 };
1703
1704   const char* nops[16] = {
1705     NULL,
1706     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
1707     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
1708   };
1709
1710   return std::string(nops[length], length);
1711 }
1712
1713 // The selector for i386 object files.
1714
1715 class Target_selector_i386 : public Target_selector
1716 {
1717 public:
1718   Target_selector_i386()
1719     : Target_selector(elfcpp::EM_386, 32, false)
1720   { }
1721
1722   Target*
1723   recognize(int machine, int osabi, int abiversion);
1724
1725  private:
1726   Target_i386* target_;
1727 };
1728
1729 // Recognize an i386 object file when we already know that the machine
1730 // number is EM_386.
1731
1732 Target*
1733 Target_selector_i386::recognize(int, int, int)
1734 {
1735   if (this->target_ == NULL)
1736     this->target_ = new Target_i386();
1737   return this->target_;
1738 }
1739
1740 Target_selector_i386 target_selector_i386;
1741
1742 } // End anonymous namespace.