gold/i386.cc

   1 // i386.cc -- i386 target support for gold.
   2
   3 // Copyright 2006, 2007, 2008, 2009 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 "copy-relocs.h"
  36 #include "target.h"
  37 #include "target-reloc.h"
  38 #include "target-select.h"
  39 #include "tls.h"
  40 #include "freebsd.h"
  41 #include "gc.h"
  42
  43 namespace
  44 {
  45
  46 using namespace gold;
  47
  48 class Output_data_plt_i386;
  49
  50 // The i386 target class.
  51 // TLS info comes from
  52 //   http://people.redhat.com/drepper/tls.pdf
  53 //   http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
  54
  55 class Target_i386 : public Target_freebsd<32, false>
  56 {
  57  public:
  58   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
  59
  60   Target_i386()
  61     : Target_freebsd<32, false>(&i386_info),
  62       got_(NULL), plt_(NULL), got_plt_(NULL), global_offset_table_(NULL),
  63       rel_dyn_(NULL), copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
  64       got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
  65   { }
  66
  67   // Process the relocations to determine unreferenced sections for
  68   // garbage collection.
  69   void
  70   gc_process_relocs(Symbol_table* symtab,
  71                     Layout* layout,
  72                     Sized_relobj<32, false>* object,
  73                     unsigned int data_shndx,
  74                     unsigned int sh_type,
  75                     const unsigned char* prelocs,
  76                     size_t reloc_count,
  77                     Output_section* output_section,
  78                     bool needs_special_offset_handling,
  79                     size_t local_symbol_count,
  80                     const unsigned char* plocal_symbols);
  81
  82   // Scan the relocations to look for symbol adjustments.
  83   void
  84   scan_relocs(Symbol_table* symtab,
  85               Layout* layout,
  86               Sized_relobj<32, false>* object,
  87               unsigned int data_shndx,
  88               unsigned int sh_type,
  89               const unsigned char* prelocs,
  90               size_t reloc_count,
  91               Output_section* output_section,
  92               bool needs_special_offset_handling,
  93               size_t local_symbol_count,
  94               const unsigned char* plocal_symbols);
  95
  96   // Finalize the sections.
  97   void
  98   do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
  99
 100   // Return the value to use for a dynamic which requires special
 101   // treatment.
 102   uint64_t
 103   do_dynsym_value(const Symbol*) const;
 104
 105   // Relocate a section.
 106   void
 107   relocate_section(const Relocate_info<32, false>*,
 108                    unsigned int sh_type,
 109                    const unsigned char* prelocs,
 110                    size_t reloc_count,
 111                    Output_section* output_section,
 112                    bool needs_special_offset_handling,
 113                    unsigned char* view,
 114                    elfcpp::Elf_types<32>::Elf_Addr view_address,
 115                    section_size_type view_size,
 116                    const Reloc_symbol_changes*);
 117
 118   // Scan the relocs during a relocatable link.
 119   void
 120   scan_relocatable_relocs(Symbol_table* symtab,
 121                           Layout* layout,
 122                           Sized_relobj<32, false>* object,
 123                           unsigned int data_shndx,
 124                           unsigned int sh_type,
 125                           const unsigned char* prelocs,
 126                           size_t reloc_count,
 127                           Output_section* output_section,
 128                           bool needs_special_offset_handling,
 129                           size_t local_symbol_count,
 130                           const unsigned char* plocal_symbols,
 131                           Relocatable_relocs*);
 132
 133   // Relocate a section during a relocatable link.
 134   void
 135   relocate_for_relocatable(const Relocate_info<32, false>*,
 136                            unsigned int sh_type,
 137                            const unsigned char* prelocs,
 138                            size_t reloc_count,
 139                            Output_section* output_section,
 140                            off_t offset_in_output_section,
 141                            const Relocatable_relocs*,
 142                            unsigned char* view,
 143                            elfcpp::Elf_types<32>::Elf_Addr view_address,
 144                            section_size_type view_size,
 145                            unsigned char* reloc_view,
 146                            section_size_type reloc_view_size);
 147
 148   // Return a string used to fill a code section with nops.
 149   std::string
 150   do_code_fill(section_size_type length) const;
 151
 152   // Return whether SYM is defined by the ABI.
 153   bool
 154   do_is_defined_by_abi(const Symbol* sym) const
 155   { return strcmp(sym->name(), "___tls_get_addr") == 0; }
 156
 157   // Return whether a symbol name implies a local label.  The UnixWare
 158   // 2.1 cc generates temporary symbols that start with .X, so we
 159   // recognize them here.  FIXME: do other SVR4 compilers also use .X?.
 160   // If so, we should move the .X recognition into
 161   // Target::do_is_local_label_name.
 162   bool
 163   do_is_local_label_name(const char* name) const
 164   {
 165     if (name[0] == '.' && name[1] == 'X')
 166       return true;
 167     return Target::do_is_local_label_name(name);
 168   }
 169
 170   // Adjust -fstack-split code which calls non-stack-split code.
 171   void
 172   do_calls_non_split(Relobj* object, unsigned int shndx,
 173                      section_offset_type fnoffset, section_size_type fnsize,
 174                      unsigned char* view, section_size_type view_size,
 175                      std::string* from, std::string* to) const;
 176
 177   // Return the size of the GOT section.
 178   section_size_type
 179   got_size()
 180   {
 181     gold_assert(this->got_ != NULL);
 182     return this->got_->data_size();
 183   }
 184
 185  private:
 186   // The class which scans relocations.
 187   struct Scan
 188   {
 189     inline void
 190     local(Symbol_table* symtab, Layout* layout, Target_i386* target,
 191           Sized_relobj<32, false>* object,
 192           unsigned int data_shndx,
 193           Output_section* output_section,
 194           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 195           const elfcpp::Sym<32, false>& lsym);
 196
 197     inline void
 198     global(Symbol_table* symtab, Layout* layout, Target_i386* target,
 199            Sized_relobj<32, false>* object,
 200            unsigned int data_shndx,
 201            Output_section* output_section,
 202            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 203            Symbol* gsym);
 204
 205     static void
 206     unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
 207
 208     static void
 209     unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
 210                              Symbol*);
 211   };
 212
 213   // The class which implements relocation.
 214   class Relocate
 215   {
 216    public:
 217     Relocate()
 218       : skip_call_tls_get_addr_(false),
 219         local_dynamic_type_(LOCAL_DYNAMIC_NONE)
 220     { }
 221
 222     ~Relocate()
 223     {
 224       if (this->skip_call_tls_get_addr_)
 225         {
 226           // FIXME: This needs to specify the location somehow.
 227           gold_error(_("missing expected TLS relocation"));
 228         }
 229     }
 230
 231     // Return whether the static relocation needs to be applied.
 232     inline bool
 233     should_apply_static_reloc(const Sized_symbol<32>* gsym,
 234                               int ref_flags,
 235                               bool is_32bit,
 236                               Output_section* output_section);
 237
 238     // Do a relocation.  Return false if the caller should not issue
 239     // any warnings about this relocation.
 240     inline bool
 241     relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
 242              size_t relnum, const elfcpp::Rel<32, false>&,
 243              unsigned int r_type, const Sized_symbol<32>*,
 244              const Symbol_value<32>*,
 245              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 246              section_size_type);
 247
 248    private:
 249     // Do a TLS relocation.
 250     inline void
 251     relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
 252                  size_t relnum, const elfcpp::Rel<32, false>&,
 253                  unsigned int r_type, const Sized_symbol<32>*,
 254                  const Symbol_value<32>*,
 255                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 256                  section_size_type);
 257
 258     // Do a TLS General-Dynamic to Initial-Exec transition.
 259     inline void
 260     tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
 261                  Output_segment* tls_segment,
 262                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 263                  elfcpp::Elf_types<32>::Elf_Addr value,
 264                  unsigned char* view,
 265                  section_size_type view_size);
 266
 267     // Do a TLS General-Dynamic to Local-Exec transition.
 268     inline void
 269     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 270                  Output_segment* tls_segment,
 271                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 272                  elfcpp::Elf_types<32>::Elf_Addr value,
 273                  unsigned char* view,
 274                  section_size_type view_size);
 275
 276     // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
 277     // transition.
 278     inline void
 279     tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
 280                       Output_segment* tls_segment,
 281                       const elfcpp::Rel<32, false>&, unsigned int r_type,
 282                       elfcpp::Elf_types<32>::Elf_Addr value,
 283                       unsigned char* view,
 284                       section_size_type view_size);
 285
 286     // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
 287     // transition.
 288     inline void
 289     tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 290                       Output_segment* tls_segment,
 291                       const elfcpp::Rel<32, false>&, unsigned int r_type,
 292                       elfcpp::Elf_types<32>::Elf_Addr value,
 293                       unsigned char* view,
 294                       section_size_type view_size);
 295
 296     // Do a TLS Local-Dynamic to Local-Exec transition.
 297     inline void
 298     tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
 299                  Output_segment* tls_segment,
 300                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 301                  elfcpp::Elf_types<32>::Elf_Addr value,
 302                  unsigned char* view,
 303                  section_size_type view_size);
 304
 305     // Do a TLS Initial-Exec to Local-Exec transition.
 306     static inline void
 307     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 308                  Output_segment* tls_segment,
 309                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 310                  elfcpp::Elf_types<32>::Elf_Addr value,
 311                  unsigned char* view,
 312                  section_size_type view_size);
 313
 314     // We need to keep track of which type of local dynamic relocation
 315     // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
 316     enum Local_dynamic_type
 317     {
 318       LOCAL_DYNAMIC_NONE,
 319       LOCAL_DYNAMIC_SUN,
 320       LOCAL_DYNAMIC_GNU
 321     };
 322
 323     // This is set if we should skip the next reloc, which should be a
 324     // PLT32 reloc against ___tls_get_addr.
 325     bool skip_call_tls_get_addr_;
 326     // The type of local dynamic relocation we have seen in the section
 327     // being relocated, if any.
 328     Local_dynamic_type local_dynamic_type_;
 329   };
 330
 331   // A class which returns the size required for a relocation type,
 332   // used while scanning relocs during a relocatable link.
 333   class Relocatable_size_for_reloc
 334   {
 335    public:
 336     unsigned int
 337     get_size_for_reloc(unsigned int, Relobj*);
 338   };
 339
 340   // Adjust TLS relocation type based on the options and whether this
 341   // is a local symbol.
 342   static tls::Tls_optimization
 343   optimize_tls_reloc(bool is_final, int r_type);
 344
 345   // Get the GOT section, creating it if necessary.
 346   Output_data_got<32, false>*
 347   got_section(Symbol_table*, Layout*);
 348
 349   // Get the GOT PLT section.
 350   Output_data_space*
 351   got_plt_section() const
 352   {
 353     gold_assert(this->got_plt_ != NULL);
 354     return this->got_plt_;
 355   }
 356
 357   // Create a PLT entry for a global symbol.
 358   void
 359   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 360
 361   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 362   void
 363   define_tls_base_symbol(Symbol_table*, Layout*);
 364
 365   // Create a GOT entry for the TLS module index.
 366   unsigned int
 367   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 368                       Sized_relobj<32, false>* object);
 369
 370   // Get the PLT section.
 371   Output_data_plt_i386*
 372   plt_section() const
 373   {
 374     gold_assert(this->plt_ != NULL);
 375     return this->plt_;
 376   }
 377
 378   // Get the dynamic reloc section, creating it if necessary.
 379   Reloc_section*
 380   rel_dyn_section(Layout*);
 381
 382   // Get the section to use for TLS_DESC relocations.
 383   Reloc_section*
 384   rel_tls_desc_section(Layout*) const;
 385
 386   // Add a potential copy relocation.
 387   void
 388   copy_reloc(Symbol_table* symtab, Layout* layout,
 389              Sized_relobj<32, false>* object,
 390              unsigned int shndx, Output_section* output_section,
 391              Symbol* sym, const elfcpp::Rel<32, false>& reloc)
 392   {
 393     this->copy_relocs_.copy_reloc(symtab, layout,
 394                                   symtab->get_sized_symbol<32>(sym),
 395                                   object, shndx, output_section, reloc,
 396                                   this->rel_dyn_section(layout));
 397   }
 398
 399   // Information about this specific target which we pass to the
 400   // general Target structure.
 401   static const Target::Target_info i386_info;
 402
 403   // The types of GOT entries needed for this platform.
 404   enum Got_type
 405   {
 406     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 407     GOT_TYPE_TLS_NOFFSET = 1,   // GOT entry for negative TLS offset
 408     GOT_TYPE_TLS_OFFSET = 2,    // GOT entry for positive TLS offset
 409     GOT_TYPE_TLS_PAIR = 3,      // GOT entry for TLS module/offset pair
 410     GOT_TYPE_TLS_DESC = 4       // GOT entry for TLS_DESC pair
 411   };
 412
 413   // The GOT section.
 414   Output_data_got<32, false>* got_;
 415   // The PLT section.
 416   Output_data_plt_i386* plt_;
 417   // The GOT PLT section.
 418   Output_data_space* got_plt_;
 419   // The _GLOBAL_OFFSET_TABLE_ symbol.
 420   Symbol* global_offset_table_;
 421   // The dynamic reloc section.
 422   Reloc_section* rel_dyn_;
 423   // Relocs saved to avoid a COPY reloc.
 424   Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
 425   // Space for variables copied with a COPY reloc.
 426   Output_data_space* dynbss_;
 427   // Offset of the GOT entry for the TLS module index.
 428   unsigned int got_mod_index_offset_;
 429   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 430   bool tls_base_symbol_defined_;
 431 };
 432
 433 const Target::Target_info Target_i386::i386_info =
 434 {
 435   32,                   // size
 436   false,                // is_big_endian
 437   elfcpp::EM_386,       // machine_code
 438   false,                // has_make_symbol
 439   false,                // has_resolve
 440   true,                 // has_code_fill
 441   true,                 // is_default_stack_executable
 442   '\0',                 // wrap_char
 443   "/usr/lib/libc.so.1", // dynamic_linker
 444   0x08048000,           // default_text_segment_address
 445   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 446   0x1000,               // common_pagesize (overridable by -z common-page-size)
 447   elfcpp::SHN_UNDEF,    // small_common_shndx
 448   elfcpp::SHN_UNDEF,    // large_common_shndx
 449   0,                    // small_common_section_flags
 450   0,                    // large_common_section_flags
 451   NULL,                 // attributes_section
 452   NULL                  // attributes_vendor
 453 };
 454
 455 // Get the GOT section, creating it if necessary.
 456
 457 Output_data_got<32, false>*
 458 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 459 {
 460   if (this->got_ == NULL)
 461     {
 462       gold_assert(symtab != NULL && layout != NULL);
 463
 464       this->got_ = new Output_data_got<32, false>();
 465
 466       Output_section* os;
 467       os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 468                                            (elfcpp::SHF_ALLOC
 469                                             | elfcpp::SHF_WRITE),
 470                                            this->got_, false, true, true,
 471                                            false);
 472
 473       this->got_plt_ = new Output_data_space(4, "** GOT PLT");
 474       os = layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 475                                            (elfcpp::SHF_ALLOC
 476                                             | elfcpp::SHF_WRITE),
 477                                            this->got_plt_, false, false, false,
 478                                            true);
 479
 480       // The first three entries are reserved.
 481       this->got_plt_->set_current_data_size(3 * 4);
 482
 483       // Those bytes can go into the relro segment.
 484       layout->increase_relro(3 * 4);
 485
 486       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 487       this->global_offset_table_ =
 488         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 489                                       Symbol_table::PREDEFINED,
 490                                       this->got_plt_,
 491                                       0, 0, elfcpp::STT_OBJECT,
 492                                       elfcpp::STB_LOCAL,
 493                                       elfcpp::STV_HIDDEN, 0,
 494                                       false, false);
 495     }
 496
 497   return this->got_;
 498 }
 499
 500 // Get the dynamic reloc section, creating it if necessary.
 501
 502 Target_i386::Reloc_section*
 503 Target_i386::rel_dyn_section(Layout* layout)
 504 {
 505   if (this->rel_dyn_ == NULL)
 506     {
 507       gold_assert(layout != NULL);
 508       this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
 509       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 510                                       elfcpp::SHF_ALLOC, this->rel_dyn_, true,
 511                                       false, false, false);
 512     }
 513   return this->rel_dyn_;
 514 }
 515
 516 // A class to handle the PLT data.
 517
 518 class Output_data_plt_i386 : public Output_section_data
 519 {
 520  public:
 521   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 522
 523   Output_data_plt_i386(Layout*, Output_data_space*);
 524
 525   // Add an entry to the PLT.
 526   void
 527   add_entry(Symbol* gsym);
 528
 529   // Return the .rel.plt section data.
 530   const Reloc_section*
 531   rel_plt() const
 532   { return this->rel_; }
 533
 534   // Return where the TLS_DESC relocations should go.
 535   Reloc_section*
 536   rel_tls_desc(Layout*);
 537
 538  protected:
 539   void
 540   do_adjust_output_section(Output_section* os);
 541
 542   // Write to a map file.
 543   void
 544   do_print_to_mapfile(Mapfile* mapfile) const
 545   { mapfile->print_output_data(this, _("** PLT")); }
 546
 547  private:
 548   // The size of an entry in the PLT.
 549   static const int plt_entry_size = 16;
 550
 551   // The first entry in the PLT for an executable.
 552   static unsigned char exec_first_plt_entry[plt_entry_size];
 553
 554   // The first entry in the PLT for a shared object.
 555   static unsigned char dyn_first_plt_entry[plt_entry_size];
 556
 557   // Other entries in the PLT for an executable.
 558   static unsigned char exec_plt_entry[plt_entry_size];
 559
 560   // Other entries in the PLT for a shared object.
 561   static unsigned char dyn_plt_entry[plt_entry_size];
 562
 563   // Set the final size.
 564   void
 565   set_final_data_size()
 566   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 567
 568   // Write out the PLT data.
 569   void
 570   do_write(Output_file*);
 571
 572   // The reloc section.
 573   Reloc_section* rel_;
 574   // The TLS_DESC relocations, if necessary.  These must follow the
 575   // regular PLT relocs.
 576   Reloc_section* tls_desc_rel_;
 577   // The .got.plt section.
 578   Output_data_space* got_plt_;
 579   // The number of PLT entries.
 580   unsigned int count_;
 581 };
 582
 583 // Create the PLT section.  The ordinary .got section is an argument,
 584 // since we need to refer to the start.  We also create our own .got
 585 // section just for PLT entries.
 586
 587 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 588                                            Output_data_space* got_plt)
 589   : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0)
 590 {
 591   this->rel_ = new Reloc_section(false);
 592   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 593                                   elfcpp::SHF_ALLOC, this->rel_, true,
 594                                   false, false, false);
 595 }
 596
 597 void
 598 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 599 {
 600   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 601   // linker, and so do we.
 602   os->set_entsize(4);
 603 }
 604
 605 // Add an entry to the PLT.
 606
 607 void
 608 Output_data_plt_i386::add_entry(Symbol* gsym)
 609 {
 610   gold_assert(!gsym->has_plt_offset());
 611
 612   // Note that when setting the PLT offset we skip the initial
 613   // reserved PLT entry.
 614   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 615
 616   ++this->count_;
 617
 618   section_offset_type got_offset = this->got_plt_->current_data_size();
 619
 620   // Every PLT entry needs a GOT entry which points back to the PLT
 621   // entry (this will be changed by the dynamic linker, normally
 622   // lazily when the function is called).
 623   this->got_plt_->set_current_data_size(got_offset + 4);
 624
 625   // Every PLT entry needs a reloc.
 626   gsym->set_needs_dynsym_entry();
 627   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 628                          got_offset);
 629
 630   // Note that we don't need to save the symbol.  The contents of the
 631   // PLT are independent of which symbols are used.  The symbols only
 632   // appear in the relocations.
 633 }
 634
 635 // Return where the TLS_DESC relocations should go, creating it if
 636 // necessary. These follow the JUMP_SLOT relocations.
 637
 638 Output_data_plt_i386::Reloc_section*
 639 Output_data_plt_i386::rel_tls_desc(Layout* layout)
 640 {
 641   if (this->tls_desc_rel_ == NULL)
 642     {
 643       this->tls_desc_rel_ = new Reloc_section(false);
 644       layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 645                                       elfcpp::SHF_ALLOC, this->tls_desc_rel_,
 646                                       true, false, false, false);
 647       gold_assert(this->tls_desc_rel_->output_section() ==
 648                   this->rel_->output_section());
 649     }
 650   return this->tls_desc_rel_;
 651 }
 652
 653 // The first entry in the PLT for an executable.
 654
 655 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 656 {
 657   0xff, 0x35,   // pushl contents of memory address
 658   0, 0, 0, 0,   // replaced with address of .got + 4
 659   0xff, 0x25,   // jmp indirect
 660   0, 0, 0, 0,   // replaced with address of .got + 8
 661   0, 0, 0, 0    // unused
 662 };
 663
 664 // The first entry in the PLT for a shared object.
 665
 666 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 667 {
 668   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 669   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 670   0, 0, 0, 0                    // unused
 671 };
 672
 673 // Subsequent entries in the PLT for an executable.
 674
 675 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 676 {
 677   0xff, 0x25,   // jmp indirect
 678   0, 0, 0, 0,   // replaced with address of symbol in .got
 679   0x68,         // pushl immediate
 680   0, 0, 0, 0,   // replaced with offset into relocation table
 681   0xe9,         // jmp relative
 682   0, 0, 0, 0    // replaced with offset to start of .plt
 683 };
 684
 685 // Subsequent entries in the PLT for a shared object.
 686
 687 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 688 {
 689   0xff, 0xa3,   // jmp *offset(%ebx)
 690   0, 0, 0, 0,   // replaced with offset of symbol in .got
 691   0x68,         // pushl immediate
 692   0, 0, 0, 0,   // replaced with offset into relocation table
 693   0xe9,         // jmp relative
 694   0, 0, 0, 0    // replaced with offset to start of .plt
 695 };
 696
 697 // Write out the PLT.  This uses the hand-coded instructions above,
 698 // and adjusts them as needed.  This is all specified by the i386 ELF
 699 // Processor Supplement.
 700
 701 void
 702 Output_data_plt_i386::do_write(Output_file* of)
 703 {
 704   const off_t offset = this->offset();
 705   const section_size_type oview_size =
 706     convert_to_section_size_type(this->data_size());
 707   unsigned char* const oview = of->get_output_view(offset, oview_size);
 708
 709   const off_t got_file_offset = this->got_plt_->offset();
 710   const section_size_type got_size =
 711     convert_to_section_size_type(this->got_plt_->data_size());
 712   unsigned char* const got_view = of->get_output_view(got_file_offset,
 713                                                       got_size);
 714
 715   unsigned char* pov = oview;
 716
 717   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 718   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 719
 720   if (parameters->options().output_is_position_independent())
 721     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 722   else
 723     {
 724       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 725       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 726       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 727     }
 728   pov += plt_entry_size;
 729
 730   unsigned char* got_pov = got_view;
 731
 732   memset(got_pov, 0, 12);
 733   got_pov += 12;
 734
 735   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 736
 737   unsigned int plt_offset = plt_entry_size;
 738   unsigned int plt_rel_offset = 0;
 739   unsigned int got_offset = 12;
 740   const unsigned int count = this->count_;
 741   for (unsigned int i = 0;
 742        i < count;
 743        ++i,
 744          pov += plt_entry_size,
 745          got_pov += 4,
 746          plt_offset += plt_entry_size,
 747          plt_rel_offset += rel_size,
 748          got_offset += 4)
 749     {
 750       // Set and adjust the PLT entry itself.
 751
 752       if (parameters->options().output_is_position_independent())
 753         {
 754           memcpy(pov, dyn_plt_entry, plt_entry_size);
 755           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 756         }
 757       else
 758         {
 759           memcpy(pov, exec_plt_entry, plt_entry_size);
 760           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 761                                                       (got_address
 762                                                        + got_offset));
 763         }
 764
 765       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 766       elfcpp::Swap<32, false>::writeval(pov + 12,
 767                                         - (plt_offset + plt_entry_size));
 768
 769       // Set the entry in the GOT.
 770       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 771     }
 772
 773   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 774   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 775
 776   of->write_output_view(offset, oview_size, oview);
 777   of->write_output_view(got_file_offset, got_size, got_view);
 778 }
 779
 780 // Create a PLT entry for a global symbol.
 781
 782 void
 783 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 784 {
 785   if (gsym->has_plt_offset())
 786     return;
 787
 788   if (this->plt_ == NULL)
 789     {
 790       // Create the GOT sections first.
 791       this->got_section(symtab, layout);
 792
 793       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 794       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 795                                       (elfcpp::SHF_ALLOC
 796                                        | elfcpp::SHF_EXECINSTR),
 797                                       this->plt_, false, false, false, false);
 798     }
 799
 800   this->plt_->add_entry(gsym);
 801 }
 802
 803 // Get the section to use for TLS_DESC relocations.
 804
 805 Target_i386::Reloc_section*
 806 Target_i386::rel_tls_desc_section(Layout* layout) const
 807 {
 808   return this->plt_section()->rel_tls_desc(layout);
 809 }
 810
 811 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 812
 813 void
 814 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
 815 {
 816   if (this->tls_base_symbol_defined_)
 817     return;
 818
 819   Output_segment* tls_segment = layout->tls_segment();
 820   if (tls_segment != NULL)
 821     {
 822       bool is_exec = parameters->options().output_is_executable();
 823       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
 824                                        Symbol_table::PREDEFINED,
 825                                        tls_segment, 0, 0,
 826                                        elfcpp::STT_TLS,
 827                                        elfcpp::STB_LOCAL,
 828                                        elfcpp::STV_HIDDEN, 0,
 829                                        (is_exec
 830                                         ? Symbol::SEGMENT_END
 831                                         : Symbol::SEGMENT_START),
 832                                        true);
 833     }
 834   this->tls_base_symbol_defined_ = true;
 835 }
 836
 837 // Create a GOT entry for the TLS module index.
 838
 839 unsigned int
 840 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 841                                  Sized_relobj<32, false>* object)
 842 {
 843   if (this->got_mod_index_offset_ == -1U)
 844     {
 845       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 846       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 847       Output_data_got<32, false>* got = this->got_section(symtab, layout);
 848       unsigned int got_offset = got->add_constant(0);
 849       rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
 850                          got_offset);
 851       got->add_constant(0);
 852       this->got_mod_index_offset_ = got_offset;
 853     }
 854   return this->got_mod_index_offset_;
 855 }
 856
 857 // Optimize the TLS relocation type based on what we know about the
 858 // symbol.  IS_FINAL is true if the final address of this symbol is
 859 // known at link time.
 860
 861 tls::Tls_optimization
 862 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 863 {
 864   // If we are generating a shared library, then we can't do anything
 865   // in the linker.
 866   if (parameters->options().shared())
 867     return tls::TLSOPT_NONE;
 868
 869   switch (r_type)
 870     {
 871     case elfcpp::R_386_TLS_GD:
 872     case elfcpp::R_386_TLS_GOTDESC:
 873     case elfcpp::R_386_TLS_DESC_CALL:
 874       // These are General-Dynamic which permits fully general TLS
 875       // access.  Since we know that we are generating an executable,
 876       // we can convert this to Initial-Exec.  If we also know that
 877       // this is a local symbol, we can further switch to Local-Exec.
 878       if (is_final)
 879         return tls::TLSOPT_TO_LE;
 880       return tls::TLSOPT_TO_IE;
 881
 882     case elfcpp::R_386_TLS_LDM:
 883       // This is Local-Dynamic, which refers to a local symbol in the
 884       // dynamic TLS block.  Since we know that we generating an
 885       // executable, we can switch to Local-Exec.
 886       return tls::TLSOPT_TO_LE;
 887
 888     case elfcpp::R_386_TLS_LDO_32:
 889       // Another type of Local-Dynamic relocation.
 890       return tls::TLSOPT_TO_LE;
 891
 892     case elfcpp::R_386_TLS_IE:
 893     case elfcpp::R_386_TLS_GOTIE:
 894     case elfcpp::R_386_TLS_IE_32:
 895       // These are Initial-Exec relocs which get the thread offset
 896       // from the GOT.  If we know that we are linking against the
 897       // local symbol, we can switch to Local-Exec, which links the
 898       // thread offset into the instruction.
 899       if (is_final)
 900         return tls::TLSOPT_TO_LE;
 901       return tls::TLSOPT_NONE;
 902
 903     case elfcpp::R_386_TLS_LE:
 904     case elfcpp::R_386_TLS_LE_32:
 905       // When we already have Local-Exec, there is nothing further we
 906       // can do.
 907       return tls::TLSOPT_NONE;
 908
 909     default:
 910       gold_unreachable();
 911     }
 912 }
 913
 914 // Report an unsupported relocation against a local symbol.
 915
 916 void
 917 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
 918                                            unsigned int r_type)
 919 {
 920   gold_error(_("%s: unsupported reloc %u against local symbol"),
 921              object->name().c_str(), r_type);
 922 }
 923
 924 // Scan a relocation for a local symbol.
 925
 926 inline void
 927 Target_i386::Scan::local(Symbol_table* symtab,
 928                          Layout* layout,
 929                          Target_i386* target,
 930                          Sized_relobj<32, false>* object,
 931                          unsigned int data_shndx,
 932                          Output_section* output_section,
 933                          const elfcpp::Rel<32, false>& reloc,
 934                          unsigned int r_type,
 935                          const elfcpp::Sym<32, false>& lsym)
 936 {
 937   switch (r_type)
 938     {
 939     case elfcpp::R_386_NONE:
 940     case elfcpp::R_386_GNU_VTINHERIT:
 941     case elfcpp::R_386_GNU_VTENTRY:
 942       break;
 943
 944     case elfcpp::R_386_32:
 945       // If building a shared library (or a position-independent
 946       // executable), we need to create a dynamic relocation for
 947       // this location. The relocation applied at link time will
 948       // apply the link-time value, so we flag the location with
 949       // an R_386_RELATIVE relocation so the dynamic loader can
 950       // relocate it easily.
 951       if (parameters->options().output_is_position_independent())
 952         {
 953           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 954           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 955           rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
 956                                       output_section, data_shndx,
 957                                       reloc.get_r_offset());
 958         }
 959       break;
 960
 961     case elfcpp::R_386_16:
 962     case elfcpp::R_386_8:
 963       // If building a shared library (or a position-independent
 964       // executable), we need to create a dynamic relocation for
 965       // this location. Because the addend needs to remain in the
 966       // data section, we need to be careful not to apply this
 967       // relocation statically.
 968       if (parameters->options().output_is_position_independent())
 969         {
 970           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 971           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 972           if (lsym.get_st_type() != elfcpp::STT_SECTION)
 973             rel_dyn->add_local(object, r_sym, r_type, output_section,
 974                                data_shndx, reloc.get_r_offset());
 975           else
 976             {
 977               gold_assert(lsym.get_st_value() == 0);
 978               unsigned int shndx = lsym.get_st_shndx();
 979               bool is_ordinary;
 980               shndx = object->adjust_sym_shndx(r_sym, shndx,
 981                                                &is_ordinary);
 982               if (!is_ordinary)
 983                 object->error(_("section symbol %u has bad shndx %u"),
 984                               r_sym, shndx);
 985               else
 986                 rel_dyn->add_local_section(object, shndx,
 987                                            r_type, output_section,
 988                                            data_shndx, reloc.get_r_offset());
 989             }
 990         }
 991       break;
 992
 993     case elfcpp::R_386_PC32:
 994     case elfcpp::R_386_PC16:
 995     case elfcpp::R_386_PC8:
 996       break;
 997
 998     case elfcpp::R_386_PLT32:
 999       // Since we know this is a local symbol, we can handle this as a
1000       // PC32 reloc.
1001       break;
1002
1003     case elfcpp::R_386_GOTOFF:
1004     case elfcpp::R_386_GOTPC:
1005       // We need a GOT section.
1006       target->got_section(symtab, layout);
1007       break;
1008
1009     case elfcpp::R_386_GOT32:
1010       {
1011         // The symbol requires a GOT entry.
1012         Output_data_got<32, false>* got = target->got_section(symtab, layout);
1013         unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1014         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
1015           {
1016             // If we are generating a shared object, we need to add a
1017             // dynamic RELATIVE relocation for this symbol's GOT entry.
1018             if (parameters->options().output_is_position_independent())
1019               {
1020                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1021                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1022                 rel_dyn->add_local_relative(
1023                     object, r_sym, elfcpp::R_386_RELATIVE, got,
1024                     object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
1025               }
1026           }
1027       }
1028       break;
1029
1030       // These are relocations which should only be seen by the
1031       // dynamic linker, and should never be seen here.
1032     case elfcpp::R_386_COPY:
1033     case elfcpp::R_386_GLOB_DAT:
1034     case elfcpp::R_386_JUMP_SLOT:
1035     case elfcpp::R_386_RELATIVE:
1036     case elfcpp::R_386_TLS_TPOFF:
1037     case elfcpp::R_386_TLS_DTPMOD32:
1038     case elfcpp::R_386_TLS_DTPOFF32:
1039     case elfcpp::R_386_TLS_TPOFF32:
1040     case elfcpp::R_386_TLS_DESC:
1041       gold_error(_("%s: unexpected reloc %u in object file"),
1042                  object->name().c_str(), r_type);
1043       break;
1044
1045       // These are initial TLS relocs, which are expected when
1046       // linking.
1047     case elfcpp::R_386_TLS_GD:            // Global-dynamic
1048     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
1049     case elfcpp::R_386_TLS_DESC_CALL:
1050     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
1051     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
1052     case elfcpp::R_386_TLS_IE:            // Initial-exec
1053     case elfcpp::R_386_TLS_IE_32:
1054     case elfcpp::R_386_TLS_GOTIE:
1055     case elfcpp::R_386_TLS_LE:            // Local-exec
1056     case elfcpp::R_386_TLS_LE_32:
1057       {
1058         bool output_is_shared = parameters->options().shared();
1059         const tls::Tls_optimization optimized_type
1060             = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1061         switch (r_type)
1062           {
1063           case elfcpp::R_386_TLS_GD:          // Global-dynamic
1064             if (optimized_type == tls::TLSOPT_NONE)
1065               {
1066                 // Create a pair of GOT entries for the module index and
1067                 // dtv-relative offset.
1068                 Output_data_got<32, false>* got
1069                     = target->got_section(symtab, layout);
1070                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1071                 unsigned int shndx = lsym.get_st_shndx();
1072                 bool is_ordinary;
1073                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1074                 if (!is_ordinary)
1075                   object->error(_("local symbol %u has bad shndx %u"),
1076                               r_sym, shndx);
1077                 else
1078                   got->add_local_pair_with_rel(object, r_sym, shndx,
1079                                                GOT_TYPE_TLS_PAIR,
1080                                                target->rel_dyn_section(layout),
1081                                                elfcpp::R_386_TLS_DTPMOD32, 0);
1082               }
1083             else if (optimized_type != tls::TLSOPT_TO_LE)
1084               unsupported_reloc_local(object, r_type);
1085             break;
1086
1087           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (from ~oliva)
1088             target->define_tls_base_symbol(symtab, layout);
1089             if (optimized_type == tls::TLSOPT_NONE)
1090               {
1091                 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1092                 Output_data_got<32, false>* got
1093                     = target->got_section(symtab, layout);
1094                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1095                 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
1096                   {
1097                     unsigned int got_offset = got->add_constant(0);
1098                     // The local symbol value is stored in the second
1099                     // GOT entry.
1100                     got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
1101                     // That set the GOT offset of the local symbol to
1102                     // point to the second entry, but we want it to
1103                     // point to the first.
1104                     object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
1105                                                  got_offset);
1106                     Reloc_section* rt = target->rel_tls_desc_section(layout);
1107                     rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
1108                   }
1109               }
1110             else if (optimized_type != tls::TLSOPT_TO_LE)
1111               unsupported_reloc_local(object, r_type);
1112             break;
1113
1114           case elfcpp::R_386_TLS_DESC_CALL:
1115             break;
1116
1117           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
1118             if (optimized_type == tls::TLSOPT_NONE)
1119               {
1120                 // Create a GOT entry for the module index.
1121                 target->got_mod_index_entry(symtab, layout, object);
1122               }
1123             else if (optimized_type != tls::TLSOPT_TO_LE)
1124               unsupported_reloc_local(object, r_type);
1125             break;
1126
1127           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
1128             break;
1129
1130           case elfcpp::R_386_TLS_IE:          // Initial-exec
1131           case elfcpp::R_386_TLS_IE_32:
1132           case elfcpp::R_386_TLS_GOTIE:
1133             layout->set_has_static_tls();
1134             if (optimized_type == tls::TLSOPT_NONE)
1135               {
1136                 // For the R_386_TLS_IE relocation, we need to create a
1137                 // dynamic relocation when building a shared library.
1138                 if (r_type == elfcpp::R_386_TLS_IE
1139                     && parameters->options().shared())
1140                   {
1141                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1142                     unsigned int r_sym
1143                         = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1144                     rel_dyn->add_local_relative(object, r_sym,
1145                                                 elfcpp::R_386_RELATIVE,
1146                                                 output_section, data_shndx,
1147                                                 reloc.get_r_offset());
1148                   }
1149                 // Create a GOT entry for the tp-relative offset.
1150                 Output_data_got<32, false>* got
1151                     = target->got_section(symtab, layout);
1152                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1153                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1154                                            ? elfcpp::R_386_TLS_TPOFF32
1155                                            : elfcpp::R_386_TLS_TPOFF);
1156                 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1157                                          ? GOT_TYPE_TLS_OFFSET
1158                                          : GOT_TYPE_TLS_NOFFSET);
1159                 got->add_local_with_rel(object, r_sym, got_type,
1160                                         target->rel_dyn_section(layout),
1161                                         dyn_r_type);
1162               }
1163             else if (optimized_type != tls::TLSOPT_TO_LE)
1164               unsupported_reloc_local(object, r_type);
1165             break;
1166
1167           case elfcpp::R_386_TLS_LE:          // Local-exec
1168           case elfcpp::R_386_TLS_LE_32:
1169             layout->set_has_static_tls();
1170             if (output_is_shared)
1171               {
1172                 // We need to create a dynamic relocation.
1173                 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1174                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1175                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1176                                            ? elfcpp::R_386_TLS_TPOFF32
1177                                            : elfcpp::R_386_TLS_TPOFF);
1178                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1179                 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1180                                    data_shndx, reloc.get_r_offset());
1181               }
1182             break;
1183
1184           default:
1185             gold_unreachable();
1186           }
1187       }
1188       break;
1189
1190     case elfcpp::R_386_32PLT:
1191     case elfcpp::R_386_TLS_GD_32:
1192     case elfcpp::R_386_TLS_GD_PUSH:
1193     case elfcpp::R_386_TLS_GD_CALL:
1194     case elfcpp::R_386_TLS_GD_POP:
1195     case elfcpp::R_386_TLS_LDM_32:
1196     case elfcpp::R_386_TLS_LDM_PUSH:
1197     case elfcpp::R_386_TLS_LDM_CALL:
1198     case elfcpp::R_386_TLS_LDM_POP:
1199     case elfcpp::R_386_USED_BY_INTEL_200:
1200     default:
1201       unsupported_reloc_local(object, r_type);
1202       break;
1203     }
1204 }
1205
1206 // Report an unsupported relocation against a global symbol.
1207
1208 void
1209 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1210                                             unsigned int r_type,
1211                                             Symbol* gsym)
1212 {
1213   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1214              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1215 }
1216
1217 // Scan a relocation for a global symbol.
1218
1219 inline void
1220 Target_i386::Scan::global(Symbol_table* symtab,
1221                           Layout* layout,
1222                           Target_i386* target,
1223                           Sized_relobj<32, false>* object,
1224                           unsigned int data_shndx,
1225                           Output_section* output_section,
1226                           const elfcpp::Rel<32, false>& reloc,
1227                           unsigned int r_type,
1228                           Symbol* gsym)
1229 {
1230   switch (r_type)
1231     {
1232     case elfcpp::R_386_NONE:
1233     case elfcpp::R_386_GNU_VTINHERIT:
1234     case elfcpp::R_386_GNU_VTENTRY:
1235       break;
1236
1237     case elfcpp::R_386_32:
1238     case elfcpp::R_386_16:
1239     case elfcpp::R_386_8:
1240       {
1241         // Make a PLT entry if necessary.
1242         if (gsym->needs_plt_entry())
1243           {
1244             target->make_plt_entry(symtab, layout, gsym);
1245             // Since this is not a PC-relative relocation, we may be
1246             // taking the address of a function. In that case we need to
1247             // set the entry in the dynamic symbol table to the address of
1248             // the PLT entry.
1249             if (gsym->is_from_dynobj() && !parameters->options().shared())
1250               gsym->set_needs_dynsym_value();
1251           }
1252         // Make a dynamic relocation if necessary.
1253         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1254           {
1255             if (gsym->may_need_copy_reloc())
1256               {
1257                 target->copy_reloc(symtab, layout, object,
1258                                    data_shndx, output_section, gsym, reloc);
1259               }
1260             else if (r_type == elfcpp::R_386_32
1261                      && gsym->can_use_relative_reloc(false))
1262               {
1263                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1264                 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1265                                              output_section, object,
1266                                              data_shndx, reloc.get_r_offset());
1267               }
1268             else
1269               {
1270                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1271                 rel_dyn->add_global(gsym, r_type, output_section, object,
1272                                     data_shndx, reloc.get_r_offset());
1273               }
1274           }
1275       }
1276       break;
1277
1278     case elfcpp::R_386_PC32:
1279     case elfcpp::R_386_PC16:
1280     case elfcpp::R_386_PC8:
1281       {
1282         // Make a PLT entry if necessary.
1283         if (gsym->needs_plt_entry())
1284           {
1285             // These relocations are used for function calls only in
1286             // non-PIC code.  For a 32-bit relocation in a shared library,
1287             // we'll need a text relocation anyway, so we can skip the
1288             // PLT entry and let the dynamic linker bind the call directly
1289             // to the target.  For smaller relocations, we should use a
1290             // PLT entry to ensure that the call can reach.
1291             if (!parameters->options().shared()
1292                 || r_type != elfcpp::R_386_PC32)
1293               target->make_plt_entry(symtab, layout, gsym);
1294           }
1295         // Make a dynamic relocation if necessary.
1296         int flags = Symbol::NON_PIC_REF;
1297         if (gsym->is_func())
1298           flags |= Symbol::FUNCTION_CALL;
1299         if (gsym->needs_dynamic_reloc(flags))
1300           {
1301             if (gsym->may_need_copy_reloc())
1302               {
1303                 target->copy_reloc(symtab, layout, object,
1304                                    data_shndx, output_section, gsym, reloc);
1305               }
1306             else
1307               {
1308                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1309                 rel_dyn->add_global(gsym, r_type, output_section, object,
1310                                     data_shndx, reloc.get_r_offset());
1311               }
1312           }
1313       }
1314       break;
1315
1316     case elfcpp::R_386_GOT32:
1317       {
1318         // The symbol requires a GOT entry.
1319         Output_data_got<32, false>* got = target->got_section(symtab, layout);
1320         if (gsym->final_value_is_known())
1321           got->add_global(gsym, GOT_TYPE_STANDARD);
1322         else
1323           {
1324             // If this symbol is not fully resolved, we need to add a
1325             // GOT entry with a dynamic relocation.
1326             Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1327             if (gsym->is_from_dynobj()
1328                 || gsym->is_undefined()
1329                 || gsym->is_preemptible())
1330               got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1331                                        rel_dyn, elfcpp::R_386_GLOB_DAT);
1332             else
1333               {
1334                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1335                   rel_dyn->add_global_relative(
1336                       gsym, elfcpp::R_386_RELATIVE, got,
1337                       gsym->got_offset(GOT_TYPE_STANDARD));
1338               }
1339           }
1340       }
1341       break;
1342
1343     case elfcpp::R_386_PLT32:
1344       // If the symbol is fully resolved, this is just a PC32 reloc.
1345       // Otherwise we need a PLT entry.
1346       if (gsym->final_value_is_known())
1347         break;
1348       // If building a shared library, we can also skip the PLT entry
1349       // if the symbol is defined in the output file and is protected
1350       // or hidden.
1351       if (gsym->is_defined()
1352           && !gsym->is_from_dynobj()
1353           && !gsym->is_preemptible())
1354         break;
1355       target->make_plt_entry(symtab, layout, gsym);
1356       break;
1357
1358     case elfcpp::R_386_GOTOFF:
1359     case elfcpp::R_386_GOTPC:
1360       // We need a GOT section.
1361       target->got_section(symtab, layout);
1362       break;
1363
1364       // These are relocations which should only be seen by the
1365       // dynamic linker, and should never be seen here.
1366     case elfcpp::R_386_COPY:
1367     case elfcpp::R_386_GLOB_DAT:
1368     case elfcpp::R_386_JUMP_SLOT:
1369     case elfcpp::R_386_RELATIVE:
1370     case elfcpp::R_386_TLS_TPOFF:
1371     case elfcpp::R_386_TLS_DTPMOD32:
1372     case elfcpp::R_386_TLS_DTPOFF32:
1373     case elfcpp::R_386_TLS_TPOFF32:
1374     case elfcpp::R_386_TLS_DESC:
1375       gold_error(_("%s: unexpected reloc %u in object file"),
1376                  object->name().c_str(), r_type);
1377       break;
1378
1379       // These are initial tls relocs, which are expected when
1380       // linking.
1381     case elfcpp::R_386_TLS_GD:            // Global-dynamic
1382     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
1383     case elfcpp::R_386_TLS_DESC_CALL:
1384     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
1385     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
1386     case elfcpp::R_386_TLS_IE:            // Initial-exec
1387     case elfcpp::R_386_TLS_IE_32:
1388     case elfcpp::R_386_TLS_GOTIE:
1389     case elfcpp::R_386_TLS_LE:            // Local-exec
1390     case elfcpp::R_386_TLS_LE_32:
1391       {
1392         const bool is_final = gsym->final_value_is_known();
1393         const tls::Tls_optimization optimized_type
1394             = Target_i386::optimize_tls_reloc(is_final, r_type);
1395         switch (r_type)
1396           {
1397           case elfcpp::R_386_TLS_GD:          // Global-dynamic
1398             if (optimized_type == tls::TLSOPT_NONE)
1399               {
1400                 // Create a pair of GOT entries for the module index and
1401                 // dtv-relative offset.
1402                 Output_data_got<32, false>* got
1403                     = target->got_section(symtab, layout);
1404                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1405                                              target->rel_dyn_section(layout),
1406                                              elfcpp::R_386_TLS_DTPMOD32,
1407                                              elfcpp::R_386_TLS_DTPOFF32);
1408               }
1409             else if (optimized_type == tls::TLSOPT_TO_IE)
1410               {
1411                 // Create a GOT entry for the tp-relative offset.
1412                 Output_data_got<32, false>* got
1413                     = target->got_section(symtab, layout);
1414                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1415                                          target->rel_dyn_section(layout),
1416                                          elfcpp::R_386_TLS_TPOFF);
1417               }
1418             else if (optimized_type != tls::TLSOPT_TO_LE)
1419               unsupported_reloc_global(object, r_type, gsym);
1420             break;
1421
1422           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (~oliva url)
1423             target->define_tls_base_symbol(symtab, layout);
1424             if (optimized_type == tls::TLSOPT_NONE)
1425               {
1426                 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1427                 Output_data_got<32, false>* got
1428                     = target->got_section(symtab, layout);
1429                 Reloc_section* rt = target->rel_tls_desc_section(layout);
1430                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
1431                                              elfcpp::R_386_TLS_DESC, 0);
1432               }
1433             else if (optimized_type == tls::TLSOPT_TO_IE)
1434               {
1435                 // Create a GOT entry for the tp-relative offset.
1436                 Output_data_got<32, false>* got
1437                     = target->got_section(symtab, layout);
1438                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1439                                          target->rel_dyn_section(layout),
1440                                          elfcpp::R_386_TLS_TPOFF);
1441               }
1442             else if (optimized_type != tls::TLSOPT_TO_LE)
1443               unsupported_reloc_global(object, r_type, gsym);
1444             break;
1445
1446           case elfcpp::R_386_TLS_DESC_CALL:
1447             break;
1448
1449           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
1450             if (optimized_type == tls::TLSOPT_NONE)
1451               {
1452                 // Create a GOT entry for the module index.
1453                 target->got_mod_index_entry(symtab, layout, object);
1454               }
1455             else if (optimized_type != tls::TLSOPT_TO_LE)
1456               unsupported_reloc_global(object, r_type, gsym);
1457             break;
1458
1459           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
1460             break;
1461
1462           case elfcpp::R_386_TLS_IE:          // Initial-exec
1463           case elfcpp::R_386_TLS_IE_32:
1464           case elfcpp::R_386_TLS_GOTIE:
1465             layout->set_has_static_tls();
1466             if (optimized_type == tls::TLSOPT_NONE)
1467               {
1468                 // For the R_386_TLS_IE relocation, we need to create a
1469                 // dynamic relocation when building a shared library.
1470                 if (r_type == elfcpp::R_386_TLS_IE
1471                     && parameters->options().shared())
1472                   {
1473                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1474                     rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1475                                                  output_section, object,
1476                                                  data_shndx,
1477                                                  reloc.get_r_offset());
1478                   }
1479                 // Create a GOT entry for the tp-relative offset.
1480                 Output_data_got<32, false>* got
1481                     = target->got_section(symtab, layout);
1482                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1483                                            ? elfcpp::R_386_TLS_TPOFF32
1484                                            : elfcpp::R_386_TLS_TPOFF);
1485                 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1486                                          ? GOT_TYPE_TLS_OFFSET
1487                                          : GOT_TYPE_TLS_NOFFSET);
1488                 got->add_global_with_rel(gsym, got_type,
1489                                          target->rel_dyn_section(layout),
1490                                          dyn_r_type);
1491               }
1492             else if (optimized_type != tls::TLSOPT_TO_LE)
1493               unsupported_reloc_global(object, r_type, gsym);
1494             break;
1495
1496           case elfcpp::R_386_TLS_LE:          // Local-exec
1497           case elfcpp::R_386_TLS_LE_32:
1498             layout->set_has_static_tls();
1499             if (parameters->options().shared())
1500               {
1501                 // We need to create a dynamic relocation.
1502                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1503                                            ? elfcpp::R_386_TLS_TPOFF32
1504                                            : elfcpp::R_386_TLS_TPOFF);
1505                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1506                 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1507                                     data_shndx, reloc.get_r_offset());
1508               }
1509             break;
1510
1511           default:
1512             gold_unreachable();
1513           }
1514       }
1515       break;
1516
1517     case elfcpp::R_386_32PLT:
1518     case elfcpp::R_386_TLS_GD_32:
1519     case elfcpp::R_386_TLS_GD_PUSH:
1520     case elfcpp::R_386_TLS_GD_CALL:
1521     case elfcpp::R_386_TLS_GD_POP:
1522     case elfcpp::R_386_TLS_LDM_32:
1523     case elfcpp::R_386_TLS_LDM_PUSH:
1524     case elfcpp::R_386_TLS_LDM_CALL:
1525     case elfcpp::R_386_TLS_LDM_POP:
1526     case elfcpp::R_386_USED_BY_INTEL_200:
1527     default:
1528       unsupported_reloc_global(object, r_type, gsym);
1529       break;
1530     }
1531 }
1532
1533 // Process relocations for gc.
1534
1535 void
1536 Target_i386::gc_process_relocs(Symbol_table* symtab,
1537                                Layout* layout,
1538                                Sized_relobj<32, false>* object,
1539                                unsigned int data_shndx,
1540                                unsigned int,
1541                                const unsigned char* prelocs,
1542                                size_t reloc_count,
1543                                Output_section* output_section,
1544                                bool needs_special_offset_handling,
1545                                size_t local_symbol_count,
1546                                const unsigned char* plocal_symbols)
1547 {
1548   gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1549                           Target_i386::Scan>(
1550     symtab,
1551     layout,
1552     this,
1553     object,
1554     data_shndx,
1555     prelocs,
1556     reloc_count,
1557     output_section,
1558     needs_special_offset_handling,
1559     local_symbol_count,
1560     plocal_symbols);
1561 }
1562
1563 // Scan relocations for a section.
1564
1565 void
1566 Target_i386::scan_relocs(Symbol_table* symtab,
1567                          Layout* layout,
1568                          Sized_relobj<32, false>* object,
1569                          unsigned int data_shndx,
1570                          unsigned int sh_type,
1571                          const unsigned char* prelocs,
1572                          size_t reloc_count,
1573                          Output_section* output_section,
1574                          bool needs_special_offset_handling,
1575                          size_t local_symbol_count,
1576                          const unsigned char* plocal_symbols)
1577 {
1578   if (sh_type == elfcpp::SHT_RELA)
1579     {
1580       gold_error(_("%s: unsupported RELA reloc section"),
1581                  object->name().c_str());
1582       return;
1583     }
1584
1585   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1586                     Target_i386::Scan>(
1587     symtab,
1588     layout,
1589     this,
1590     object,
1591     data_shndx,
1592     prelocs,
1593     reloc_count,
1594     output_section,
1595     needs_special_offset_handling,
1596     local_symbol_count,
1597     plocal_symbols);
1598 }
1599
1600 // Finalize the sections.
1601
1602 void
1603 Target_i386::do_finalize_sections(
1604     Layout* layout,
1605     const Input_objects*,
1606     Symbol_table* symtab)
1607 {
1608   const Reloc_section* rel_plt = (this->plt_ == NULL
1609                                   ? NULL
1610                                   : this->plt_->rel_plt());
1611   layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
1612                                   this->rel_dyn_, true);
1613
1614   // Emit any relocs we saved in an attempt to avoid generating COPY
1615   // relocs.
1616   if (this->copy_relocs_.any_saved_relocs())
1617     this->copy_relocs_.emit(this->rel_dyn_section(layout));
1618
1619   // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
1620   // the .got.plt section.
1621   Symbol* sym = this->global_offset_table_;
1622   if (sym != NULL)
1623     {
1624       uint32_t data_size = this->got_plt_->current_data_size();
1625       symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
1626     }
1627 }
1628
1629 // Return whether a direct absolute static relocation needs to be applied.
1630 // In cases where Scan::local() or Scan::global() has created
1631 // a dynamic relocation other than R_386_RELATIVE, the addend
1632 // of the relocation is carried in the data, and we must not
1633 // apply the static relocation.
1634
1635 inline bool
1636 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1637                                                  int ref_flags,
1638                                                  bool is_32bit,
1639                                                  Output_section* output_section)
1640 {
1641   // If the output section is not allocated, then we didn't call
1642   // scan_relocs, we didn't create a dynamic reloc, and we must apply
1643   // the reloc here.
1644   if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1645     return true;
1646
1647   // For local symbols, we will have created a non-RELATIVE dynamic
1648   // relocation only if (a) the output is position independent,
1649   // (b) the relocation is absolute (not pc- or segment-relative), and
1650   // (c) the relocation is not 32 bits wide.
1651   if (gsym == NULL)
1652     return !(parameters->options().output_is_position_independent()
1653              && (ref_flags & Symbol::ABSOLUTE_REF)
1654              && !is_32bit);
1655
1656   // For global symbols, we use the same helper routines used in the
1657   // scan pass.  If we did not create a dynamic relocation, or if we
1658   // created a RELATIVE dynamic relocation, we should apply the static
1659   // relocation.
1660   bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1661   bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1662                 && gsym->can_use_relative_reloc(ref_flags
1663                                                 & Symbol::FUNCTION_CALL);
1664   return !has_dyn || is_rel;
1665 }
1666
1667 // Perform a relocation.
1668
1669 inline bool
1670 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1671                                 Target_i386* target,
1672                                 Output_section *output_section,
1673                                 size_t relnum,
1674                                 const elfcpp::Rel<32, false>& rel,
1675                                 unsigned int r_type,
1676                                 const Sized_symbol<32>* gsym,
1677                                 const Symbol_value<32>* psymval,
1678                                 unsigned char* view,
1679                                 elfcpp::Elf_types<32>::Elf_Addr address,
1680                                 section_size_type view_size)
1681 {
1682   if (this->skip_call_tls_get_addr_)
1683     {
1684       if ((r_type != elfcpp::R_386_PLT32
1685            && r_type != elfcpp::R_386_PC32)
1686           || gsym == NULL
1687           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1688         gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1689                                _("missing expected TLS relocation"));
1690       else
1691         {
1692           this->skip_call_tls_get_addr_ = false;
1693           return false;
1694         }
1695     }
1696
1697   // Pick the value to use for symbols defined in shared objects.
1698   Symbol_value<32> symval;
1699   if (gsym != NULL
1700       && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1701                               || r_type == elfcpp::R_386_PC16
1702                               || r_type == elfcpp::R_386_PC32))
1703     {
1704       symval.set_output_value(target->plt_section()->address()
1705                               + gsym->plt_offset());
1706       psymval = &symval;
1707     }
1708
1709   const Sized_relobj<32, false>* object = relinfo->object;
1710
1711   // Get the GOT offset if needed.
1712   // The GOT pointer points to the end of the GOT section.
1713   // We need to subtract the size of the GOT section to get
1714   // the actual offset to use in the relocation.
1715   bool have_got_offset = false;
1716   unsigned int got_offset = 0;
1717   switch (r_type)
1718     {
1719     case elfcpp::R_386_GOT32:
1720       if (gsym != NULL)
1721         {
1722           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1723           got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1724                         - target->got_size());
1725         }
1726       else
1727         {
1728           unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1729           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1730           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1731                         - target->got_size());
1732         }
1733       have_got_offset = true;
1734       break;
1735
1736     default:
1737       break;
1738     }
1739
1740   switch (r_type)
1741     {
1742     case elfcpp::R_386_NONE:
1743     case elfcpp::R_386_GNU_VTINHERIT:
1744     case elfcpp::R_386_GNU_VTENTRY:
1745       break;
1746
1747     case elfcpp::R_386_32:
1748       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1749                                     output_section))
1750         Relocate_functions<32, false>::rel32(view, object, psymval);
1751       break;
1752
1753     case elfcpp::R_386_PC32:
1754       {
1755         int ref_flags = Symbol::NON_PIC_REF;
1756         if (gsym != NULL && gsym->is_func())
1757           ref_flags |= Symbol::FUNCTION_CALL;
1758         if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1759           Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1760       }
1761       break;
1762
1763     case elfcpp::R_386_16:
1764       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1765                                     output_section))
1766         Relocate_functions<32, false>::rel16(view, object, psymval);
1767       break;
1768
1769     case elfcpp::R_386_PC16:
1770       {
1771         int ref_flags = Symbol::NON_PIC_REF;
1772         if (gsym != NULL && gsym->is_func())
1773           ref_flags |= Symbol::FUNCTION_CALL;
1774         if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1775           Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1776       }
1777       break;
1778
1779     case elfcpp::R_386_8:
1780       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1781                                     output_section))
1782         Relocate_functions<32, false>::rel8(view, object, psymval);
1783       break;
1784
1785     case elfcpp::R_386_PC8:
1786       {
1787         int ref_flags = Symbol::NON_PIC_REF;
1788         if (gsym != NULL && gsym->is_func())
1789           ref_flags |= Symbol::FUNCTION_CALL;
1790         if (should_apply_static_reloc(gsym, ref_flags, false,
1791                                       output_section))
1792           Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1793       }
1794       break;
1795
1796     case elfcpp::R_386_PLT32:
1797       gold_assert(gsym == NULL
1798                   || gsym->has_plt_offset()
1799                   || gsym->final_value_is_known()
1800                   || (gsym->is_defined()
1801                       && !gsym->is_from_dynobj()
1802                       && !gsym->is_preemptible()));
1803       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1804       break;
1805
1806     case elfcpp::R_386_GOT32:
1807       gold_assert(have_got_offset);
1808       Relocate_functions<32, false>::rel32(view, got_offset);
1809       break;
1810
1811     case elfcpp::R_386_GOTOFF:
1812       {
1813         elfcpp::Elf_types<32>::Elf_Addr value;
1814         value = (psymval->value(object, 0)
1815                  - target->got_plt_section()->address());
1816         Relocate_functions<32, false>::rel32(view, value);
1817       }
1818       break;
1819
1820     case elfcpp::R_386_GOTPC:
1821       {
1822         elfcpp::Elf_types<32>::Elf_Addr value;
1823         value = target->got_plt_section()->address();
1824         Relocate_functions<32, false>::pcrel32(view, value, address);
1825       }
1826       break;
1827
1828     case elfcpp::R_386_COPY:
1829     case elfcpp::R_386_GLOB_DAT:
1830     case elfcpp::R_386_JUMP_SLOT:
1831     case elfcpp::R_386_RELATIVE:
1832       // These are outstanding tls relocs, which are unexpected when
1833       // linking.
1834     case elfcpp::R_386_TLS_TPOFF:
1835     case elfcpp::R_386_TLS_DTPMOD32:
1836     case elfcpp::R_386_TLS_DTPOFF32:
1837     case elfcpp::R_386_TLS_TPOFF32:
1838     case elfcpp::R_386_TLS_DESC:
1839       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1840                              _("unexpected reloc %u in object file"),
1841                              r_type);
1842       break;
1843
1844       // These are initial tls relocs, which are expected when
1845       // linking.
1846     case elfcpp::R_386_TLS_GD:             // Global-dynamic
1847     case elfcpp::R_386_TLS_GOTDESC:        // Global-dynamic (from ~oliva url)
1848     case elfcpp::R_386_TLS_DESC_CALL:
1849     case elfcpp::R_386_TLS_LDM:            // Local-dynamic
1850     case elfcpp::R_386_TLS_LDO_32:         // Alternate local-dynamic
1851     case elfcpp::R_386_TLS_IE:             // Initial-exec
1852     case elfcpp::R_386_TLS_IE_32:
1853     case elfcpp::R_386_TLS_GOTIE:
1854     case elfcpp::R_386_TLS_LE:             // Local-exec
1855     case elfcpp::R_386_TLS_LE_32:
1856       this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1857                          view, address, view_size);
1858       break;
1859
1860     case elfcpp::R_386_32PLT:
1861     case elfcpp::R_386_TLS_GD_32:
1862     case elfcpp::R_386_TLS_GD_PUSH:
1863     case elfcpp::R_386_TLS_GD_CALL:
1864     case elfcpp::R_386_TLS_GD_POP:
1865     case elfcpp::R_386_TLS_LDM_32:
1866     case elfcpp::R_386_TLS_LDM_PUSH:
1867     case elfcpp::R_386_TLS_LDM_CALL:
1868     case elfcpp::R_386_TLS_LDM_POP:
1869     case elfcpp::R_386_USED_BY_INTEL_200:
1870     default:
1871       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1872                              _("unsupported reloc %u"),
1873                              r_type);
1874       break;
1875     }
1876
1877   return true;
1878 }
1879
1880 // Perform a TLS relocation.
1881
1882 inline void
1883 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1884                                     Target_i386* target,
1885                                     size_t relnum,
1886                                     const elfcpp::Rel<32, false>& rel,
1887                                     unsigned int r_type,
1888                                     const Sized_symbol<32>* gsym,
1889                                     const Symbol_value<32>* psymval,
1890                                     unsigned char* view,
1891                                     elfcpp::Elf_types<32>::Elf_Addr,
1892                                     section_size_type view_size)
1893 {
1894   Output_segment* tls_segment = relinfo->layout->tls_segment();
1895
1896   const Sized_relobj<32, false>* object = relinfo->object;
1897
1898   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1899
1900   const bool is_final =
1901     (gsym == NULL
1902      ? !parameters->options().output_is_position_independent()
1903      : gsym->final_value_is_known());
1904   const tls::Tls_optimization optimized_type
1905       = Target_i386::optimize_tls_reloc(is_final, r_type);
1906   switch (r_type)
1907     {
1908     case elfcpp::R_386_TLS_GD:           // Global-dynamic
1909       if (optimized_type == tls::TLSOPT_TO_LE)
1910         {
1911           gold_assert(tls_segment != NULL);
1912           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1913                              rel, r_type, value, view,
1914                              view_size);
1915           break;
1916         }
1917       else
1918         {
1919           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1920                                    ? GOT_TYPE_TLS_NOFFSET
1921                                    : GOT_TYPE_TLS_PAIR);
1922           unsigned int got_offset;
1923           if (gsym != NULL)
1924             {
1925               gold_assert(gsym->has_got_offset(got_type));
1926               got_offset = gsym->got_offset(got_type) - target->got_size();
1927             }
1928           else
1929             {
1930               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1931               gold_assert(object->local_has_got_offset(r_sym, got_type));
1932               got_offset = (object->local_got_offset(r_sym, got_type)
1933                             - target->got_size());
1934             }
1935           if (optimized_type == tls::TLSOPT_TO_IE)
1936             {
1937               gold_assert(tls_segment != NULL);
1938               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1939                                  got_offset, view, view_size);
1940               break;
1941             }
1942           else if (optimized_type == tls::TLSOPT_NONE)
1943             {
1944               // Relocate the field with the offset of the pair of GOT
1945               // entries.
1946               Relocate_functions<32, false>::rel32(view, got_offset);
1947               break;
1948             }
1949         }
1950       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1951                              _("unsupported reloc %u"),
1952                              r_type);
1953       break;
1954
1955     case elfcpp::R_386_TLS_GOTDESC:      // Global-dynamic (from ~oliva url)
1956     case elfcpp::R_386_TLS_DESC_CALL:
1957       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1958       if (optimized_type == tls::TLSOPT_TO_LE)
1959         {
1960           gold_assert(tls_segment != NULL);
1961           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
1962                                   rel, r_type, value, view,
1963                                   view_size);
1964           break;
1965         }
1966       else
1967         {
1968           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1969                                    ? GOT_TYPE_TLS_NOFFSET
1970                                    : GOT_TYPE_TLS_DESC);
1971           unsigned int got_offset;
1972           if (gsym != NULL)
1973             {
1974               gold_assert(gsym->has_got_offset(got_type));
1975               got_offset = gsym->got_offset(got_type) - target->got_size();
1976             }
1977           else
1978             {
1979               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1980               gold_assert(object->local_has_got_offset(r_sym, got_type));
1981               got_offset = (object->local_got_offset(r_sym, got_type)
1982                             - target->got_size());
1983             }
1984           if (optimized_type == tls::TLSOPT_TO_IE)
1985             {
1986               gold_assert(tls_segment != NULL);
1987               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1988                                       got_offset, view, view_size);
1989               break;
1990             }
1991           else if (optimized_type == tls::TLSOPT_NONE)
1992             {
1993               if (r_type == elfcpp::R_386_TLS_GOTDESC)
1994                 {
1995                   // Relocate the field with the offset of the pair of GOT
1996                   // entries.
1997                   Relocate_functions<32, false>::rel32(view, got_offset);
1998                 }
1999               break;
2000             }
2001         }
2002       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2003                              _("unsupported reloc %u"),
2004                              r_type);
2005       break;
2006
2007     case elfcpp::R_386_TLS_LDM:          // Local-dynamic
2008       if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
2009         {
2010           gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2011                                  _("both SUN and GNU model "
2012                                    "TLS relocations"));
2013           break;
2014         }
2015       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
2016       if (optimized_type == tls::TLSOPT_TO_LE)
2017         {
2018           gold_assert(tls_segment != NULL);
2019           this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
2020                              value, view, view_size);
2021           break;
2022         }
2023       else if (optimized_type == tls::TLSOPT_NONE)
2024         {
2025           // Relocate the field with the offset of the GOT entry for
2026           // the module index.
2027           unsigned int got_offset;
2028           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2029                         - target->got_size());
2030           Relocate_functions<32, false>::rel32(view, got_offset);
2031           break;
2032         }
2033       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2034                              _("unsupported reloc %u"),
2035                              r_type);
2036       break;
2037
2038     case elfcpp::R_386_TLS_LDO_32:       // Alternate local-dynamic
2039       if (optimized_type == tls::TLSOPT_TO_LE)
2040         {
2041           // This reloc can appear in debugging sections, in which
2042           // case we must not convert to local-exec.  We decide what
2043           // to do based on whether the section is marked as
2044           // containing executable code.  That is what the GNU linker
2045           // does as well.
2046           elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2047           if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2048             {
2049               gold_assert(tls_segment != NULL);
2050               value -= tls_segment->memsz();
2051             }
2052         }
2053       Relocate_functions<32, false>::rel32(view, value);
2054       break;
2055
2056     case elfcpp::R_386_TLS_IE:           // Initial-exec
2057     case elfcpp::R_386_TLS_GOTIE:
2058     case elfcpp::R_386_TLS_IE_32:
2059       if (optimized_type == tls::TLSOPT_TO_LE)
2060         {
2061           gold_assert(tls_segment != NULL);
2062           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2063                                               rel, r_type, value, view,
2064                                               view_size);
2065           break;
2066         }
2067       else if (optimized_type == tls::TLSOPT_NONE)
2068         {
2069           // Relocate the field with the offset of the GOT entry for
2070           // the tp-relative offset of the symbol.
2071           unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2072                                    ? GOT_TYPE_TLS_OFFSET
2073                                    : GOT_TYPE_TLS_NOFFSET);
2074           unsigned int got_offset;
2075           if (gsym != NULL)
2076             {
2077               gold_assert(gsym->has_got_offset(got_type));
2078               got_offset = gsym->got_offset(got_type);
2079             }
2080           else
2081             {
2082               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2083               gold_assert(object->local_has_got_offset(r_sym, got_type));
2084               got_offset = object->local_got_offset(r_sym, got_type);
2085             }
2086           // For the R_386_TLS_IE relocation, we need to apply the
2087           // absolute address of the GOT entry.
2088           if (r_type == elfcpp::R_386_TLS_IE)
2089             got_offset += target->got_plt_section()->address();
2090           // All GOT offsets are relative to the end of the GOT.
2091           got_offset -= target->got_size();
2092           Relocate_functions<32, false>::rel32(view, got_offset);
2093           break;
2094         }
2095       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2096                              _("unsupported reloc %u"),
2097                              r_type);
2098       break;
2099
2100     case elfcpp::R_386_TLS_LE:           // Local-exec
2101       // If we're creating a shared library, a dynamic relocation will
2102       // have been created for this location, so do not apply it now.
2103       if (!parameters->options().shared())
2104         {
2105           gold_assert(tls_segment != NULL);
2106           value -= tls_segment->memsz();
2107           Relocate_functions<32, false>::rel32(view, value);
2108         }
2109       break;
2110
2111     case elfcpp::R_386_TLS_LE_32:
2112       // If we're creating a shared library, a dynamic relocation will
2113       // have been created for this location, so do not apply it now.
2114       if (!parameters->options().shared())
2115         {
2116           gold_assert(tls_segment != NULL);
2117           value = tls_segment->memsz() - value;
2118           Relocate_functions<32, false>::rel32(view, value);
2119         }
2120       break;
2121     }
2122 }
2123
2124 // Do a relocation in which we convert a TLS General-Dynamic to a
2125 // Local-Exec.
2126
2127 inline void
2128 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2129                                     size_t relnum,
2130                                     Output_segment* tls_segment,
2131                                     const elfcpp::Rel<32, false>& rel,
2132                                     unsigned int,
2133                                     elfcpp::Elf_types<32>::Elf_Addr value,
2134                                     unsigned char* view,
2135                                     section_size_type view_size)
2136 {
2137   // leal foo(,%reg,1),%eax; call ___tls_get_addr
2138   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2139   // leal foo(%reg),%eax; call ___tls_get_addr
2140   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2141
2142   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2143   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2144
2145   unsigned char op1 = view[-1];
2146   unsigned char op2 = view[-2];
2147
2148   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2149                  op2 == 0x8d || op2 == 0x04);
2150   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2151
2152   int roff = 5;
2153
2154   if (op2 == 0x04)
2155     {
2156       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2157       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2158       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2159                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2160       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2161     }
2162   else
2163     {
2164       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2165                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2166       if (rel.get_r_offset() + 9 < view_size
2167           && view[9] == 0x90)
2168         {
2169           // There is a trailing nop.  Use the size byte subl.
2170           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2171           roff = 6;
2172         }
2173       else
2174         {
2175           // Use the five byte subl.
2176           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2177         }
2178     }
2179
2180   value = tls_segment->memsz() - value;
2181   Relocate_functions<32, false>::rel32(view + roff, value);
2182
2183   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2184   // We can skip it.
2185   this->skip_call_tls_get_addr_ = true;
2186 }
2187
2188 // Do a relocation in which we convert a TLS General-Dynamic to an
2189 // Initial-Exec.
2190
2191 inline void
2192 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2193                                     size_t relnum,
2194                                     Output_segment*,
2195                                     const elfcpp::Rel<32, false>& rel,
2196                                     unsigned int,
2197                                     elfcpp::Elf_types<32>::Elf_Addr value,
2198                                     unsigned char* view,
2199                                     section_size_type view_size)
2200 {
2201   // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2202   //  ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2203
2204   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2205   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2206
2207   unsigned char op1 = view[-1];
2208   unsigned char op2 = view[-2];
2209
2210   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2211                  op2 == 0x8d || op2 == 0x04);
2212   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2213
2214   int roff = 5;
2215
2216   // FIXME: For now, support only the first (SIB) form.
2217   tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2218
2219   if (op2 == 0x04)
2220     {
2221       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2222       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2223       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2224                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2225       memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2226     }
2227   else
2228     {
2229       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2230                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2231       if (rel.get_r_offset() + 9 < view_size
2232           && view[9] == 0x90)
2233         {
2234           // FIXME: This is not the right instruction sequence.
2235           // There is a trailing nop.  Use the size byte subl.
2236           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2237           roff = 6;
2238         }
2239       else
2240         {
2241           // FIXME: This is not the right instruction sequence.
2242           // Use the five byte subl.
2243           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2244         }
2245     }
2246
2247   Relocate_functions<32, false>::rel32(view + roff, value);
2248
2249   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2250   // We can skip it.
2251   this->skip_call_tls_get_addr_ = true;
2252 }
2253
2254 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2255 // General-Dynamic to a Local-Exec.
2256
2257 inline void
2258 Target_i386::Relocate::tls_desc_gd_to_le(
2259     const Relocate_info<32, false>* relinfo,
2260     size_t relnum,
2261     Output_segment* tls_segment,
2262     const elfcpp::Rel<32, false>& rel,
2263     unsigned int r_type,
2264     elfcpp::Elf_types<32>::Elf_Addr value,
2265     unsigned char* view,
2266     section_size_type view_size)
2267 {
2268   if (r_type == elfcpp::R_386_TLS_GOTDESC)
2269     {
2270       // leal foo@TLSDESC(%ebx), %eax
2271       // ==> leal foo@NTPOFF, %eax
2272       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2273       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2274       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2275                      view[-2] == 0x8d && view[-1] == 0x83);
2276       view[-1] = 0x05;
2277       value -= tls_segment->memsz();
2278       Relocate_functions<32, false>::rel32(view, value);
2279     }
2280   else
2281     {
2282       // call *foo@TLSCALL(%eax)
2283       // ==> nop; nop
2284       gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2285       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2286       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2287                      view[0] == 0xff && view[1] == 0x10);
2288       view[0] = 0x66;
2289       view[1] = 0x90;
2290     }
2291 }
2292
2293 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2294 // General-Dynamic to an Initial-Exec.
2295
2296 inline void
2297 Target_i386::Relocate::tls_desc_gd_to_ie(
2298     const Relocate_info<32, false>* relinfo,
2299     size_t relnum,
2300     Output_segment*,
2301     const elfcpp::Rel<32, false>& rel,
2302     unsigned int r_type,
2303     elfcpp::Elf_types<32>::Elf_Addr value,
2304     unsigned char* view,
2305     section_size_type view_size)
2306 {
2307   if (r_type == elfcpp::R_386_TLS_GOTDESC)
2308     {
2309       // leal foo@TLSDESC(%ebx), %eax
2310       // ==> movl foo@GOTNTPOFF(%ebx), %eax
2311       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2312       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2313       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2314                      view[-2] == 0x8d && view[-1] == 0x83);
2315       view[-2] = 0x8b;
2316       Relocate_functions<32, false>::rel32(view, value);
2317     }
2318   else
2319     {
2320       // call *foo@TLSCALL(%eax)
2321       // ==> nop; nop
2322       gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2323       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2324       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2325                      view[0] == 0xff && view[1] == 0x10);
2326       view[0] = 0x66;
2327       view[1] = 0x90;
2328     }
2329 }
2330
2331 // Do a relocation in which we convert a TLS Local-Dynamic to a
2332 // Local-Exec.
2333
2334 inline void
2335 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2336                                     size_t relnum,
2337                                     Output_segment*,
2338                                     const elfcpp::Rel<32, false>& rel,
2339                                     unsigned int,
2340                                     elfcpp::Elf_types<32>::Elf_Addr,
2341                                     unsigned char* view,
2342                                     section_size_type view_size)
2343 {
2344   // leal foo(%reg), %eax; call ___tls_get_addr
2345   // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2346
2347   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2348   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2349
2350   // FIXME: Does this test really always pass?
2351   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2352                  view[-2] == 0x8d && view[-1] == 0x83);
2353
2354   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2355
2356   memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2357
2358   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2359   // We can skip it.
2360   this->skip_call_tls_get_addr_ = true;
2361 }
2362
2363 // Do a relocation in which we convert a TLS Initial-Exec to a
2364 // Local-Exec.
2365
2366 inline void
2367 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2368                                     size_t relnum,
2369                                     Output_segment* tls_segment,
2370                                     const elfcpp::Rel<32, false>& rel,
2371                                     unsigned int r_type,
2372                                     elfcpp::Elf_types<32>::Elf_Addr value,
2373                                     unsigned char* view,
2374                                     section_size_type view_size)
2375 {
2376   // We have to actually change the instructions, which means that we
2377   // need to examine the opcodes to figure out which instruction we
2378   // are looking at.
2379   if (r_type == elfcpp::R_386_TLS_IE)
2380     {
2381       // movl %gs:XX,%eax  ==>  movl $YY,%eax
2382       // movl %gs:XX,%reg  ==>  movl $YY,%reg
2383       // addl %gs:XX,%reg  ==>  addl $YY,%reg
2384       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2385       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2386
2387       unsigned char op1 = view[-1];
2388       if (op1 == 0xa1)
2389         {
2390           // movl XX,%eax  ==>  movl $YY,%eax
2391           view[-1] = 0xb8;
2392         }
2393       else
2394         {
2395           tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2396
2397           unsigned char op2 = view[-2];
2398           if (op2 == 0x8b)
2399             {
2400               // movl XX,%reg  ==>  movl $YY,%reg
2401               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2402                              (op1 & 0xc7) == 0x05);
2403               view[-2] = 0xc7;
2404               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2405             }
2406           else if (op2 == 0x03)
2407             {
2408               // addl XX,%reg  ==>  addl $YY,%reg
2409               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2410                              (op1 & 0xc7) == 0x05);
2411               view[-2] = 0x81;
2412               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2413             }
2414           else
2415             tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2416         }
2417     }
2418   else
2419     {
2420       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2421       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2422       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2423       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2424       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2425
2426       unsigned char op1 = view[-1];
2427       unsigned char op2 = view[-2];
2428       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2429                      (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2430       if (op2 == 0x8b)
2431         {
2432           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2433           view[-2] = 0xc7;
2434           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2435         }
2436       else if (op2 == 0x2b)
2437         {
2438           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2439           view[-2] = 0x81;
2440           view[-1] = 0xe8 | ((op1 >> 3) & 7);
2441         }
2442       else if (op2 == 0x03)
2443         {
2444           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2445           view[-2] = 0x81;
2446           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2447         }
2448       else
2449         tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2450     }
2451
2452   value = tls_segment->memsz() - value;
2453   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2454     value = - value;
2455
2456   Relocate_functions<32, false>::rel32(view, value);
2457 }
2458
2459 // Relocate section data.
2460
2461 void
2462 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2463                               unsigned int sh_type,
2464                               const unsigned char* prelocs,
2465                               size_t reloc_count,
2466                               Output_section* output_section,
2467                               bool needs_special_offset_handling,
2468                               unsigned char* view,
2469                               elfcpp::Elf_types<32>::Elf_Addr address,
2470                               section_size_type view_size,
2471                               const Reloc_symbol_changes* reloc_symbol_changes)
2472 {
2473   gold_assert(sh_type == elfcpp::SHT_REL);
2474
2475   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2476                          Target_i386::Relocate>(
2477     relinfo,
2478     this,
2479     prelocs,
2480     reloc_count,
2481     output_section,
2482     needs_special_offset_handling,
2483     view,
2484     address,
2485     view_size,
2486     reloc_symbol_changes);
2487 }
2488
2489 // Return the size of a relocation while scanning during a relocatable
2490 // link.
2491
2492 unsigned int
2493 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2494     unsigned int r_type,
2495     Relobj* object)
2496 {
2497   switch (r_type)
2498     {
2499     case elfcpp::R_386_NONE:
2500     case elfcpp::R_386_GNU_VTINHERIT:
2501     case elfcpp::R_386_GNU_VTENTRY:
2502     case elfcpp::R_386_TLS_GD:            // Global-dynamic
2503     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
2504     case elfcpp::R_386_TLS_DESC_CALL:
2505     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
2506     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
2507     case elfcpp::R_386_TLS_IE:            // Initial-exec
2508     case elfcpp::R_386_TLS_IE_32:
2509     case elfcpp::R_386_TLS_GOTIE:
2510     case elfcpp::R_386_TLS_LE:            // Local-exec
2511     case elfcpp::R_386_TLS_LE_32:
2512       return 0;
2513
2514     case elfcpp::R_386_32:
2515     case elfcpp::R_386_PC32:
2516     case elfcpp::R_386_GOT32:
2517     case elfcpp::R_386_PLT32:
2518     case elfcpp::R_386_GOTOFF:
2519     case elfcpp::R_386_GOTPC:
2520      return 4;
2521
2522     case elfcpp::R_386_16:
2523     case elfcpp::R_386_PC16:
2524       return 2;
2525
2526     case elfcpp::R_386_8:
2527     case elfcpp::R_386_PC8:
2528       return 1;
2529
2530       // These are relocations which should only be seen by the
2531       // dynamic linker, and should never be seen here.
2532     case elfcpp::R_386_COPY:
2533     case elfcpp::R_386_GLOB_DAT:
2534     case elfcpp::R_386_JUMP_SLOT:
2535     case elfcpp::R_386_RELATIVE:
2536     case elfcpp::R_386_TLS_TPOFF:
2537     case elfcpp::R_386_TLS_DTPMOD32:
2538     case elfcpp::R_386_TLS_DTPOFF32:
2539     case elfcpp::R_386_TLS_TPOFF32:
2540     case elfcpp::R_386_TLS_DESC:
2541       object->error(_("unexpected reloc %u in object file"), r_type);
2542       return 0;
2543
2544     case elfcpp::R_386_32PLT:
2545     case elfcpp::R_386_TLS_GD_32:
2546     case elfcpp::R_386_TLS_GD_PUSH:
2547     case elfcpp::R_386_TLS_GD_CALL:
2548     case elfcpp::R_386_TLS_GD_POP:
2549     case elfcpp::R_386_TLS_LDM_32:
2550     case elfcpp::R_386_TLS_LDM_PUSH:
2551     case elfcpp::R_386_TLS_LDM_CALL:
2552     case elfcpp::R_386_TLS_LDM_POP:
2553     case elfcpp::R_386_USED_BY_INTEL_200:
2554     default:
2555       object->error(_("unsupported reloc %u in object file"), r_type);
2556       return 0;
2557     }
2558 }
2559
2560 // Scan the relocs during a relocatable link.
2561
2562 void
2563 Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
2564                                      Layout* layout,
2565                                      Sized_relobj<32, false>* object,
2566                                      unsigned int data_shndx,
2567                                      unsigned int sh_type,
2568                                      const unsigned char* prelocs,
2569                                      size_t reloc_count,
2570                                      Output_section* output_section,
2571                                      bool needs_special_offset_handling,
2572                                      size_t local_symbol_count,
2573                                      const unsigned char* plocal_symbols,
2574                                      Relocatable_relocs* rr)
2575 {
2576   gold_assert(sh_type == elfcpp::SHT_REL);
2577
2578   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2579     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2580
2581   gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2582       Scan_relocatable_relocs>(
2583     symtab,
2584     layout,
2585     object,
2586     data_shndx,
2587     prelocs,
2588     reloc_count,
2589     output_section,
2590     needs_special_offset_handling,
2591     local_symbol_count,
2592     plocal_symbols,
2593     rr);
2594 }
2595
2596 // Relocate a section during a relocatable link.
2597
2598 void
2599 Target_i386::relocate_for_relocatable(
2600     const Relocate_info<32, false>* relinfo,
2601     unsigned int sh_type,
2602     const unsigned char* prelocs,
2603     size_t reloc_count,
2604     Output_section* output_section,
2605     off_t offset_in_output_section,
2606     const Relocatable_relocs* rr,
2607     unsigned char* view,
2608     elfcpp::Elf_types<32>::Elf_Addr view_address,
2609     section_size_type view_size,
2610     unsigned char* reloc_view,
2611     section_size_type reloc_view_size)
2612 {
2613   gold_assert(sh_type == elfcpp::SHT_REL);
2614
2615   gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2616     relinfo,
2617     prelocs,
2618     reloc_count,
2619     output_section,
2620     offset_in_output_section,
2621     rr,
2622     view,
2623     view_address,
2624     view_size,
2625     reloc_view,
2626     reloc_view_size);
2627 }
2628
2629 // Return the value to use for a dynamic which requires special
2630 // treatment.  This is how we support equality comparisons of function
2631 // pointers across shared library boundaries, as described in the
2632 // processor specific ABI supplement.
2633
2634 uint64_t
2635 Target_i386::do_dynsym_value(const Symbol* gsym) const
2636 {
2637   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2638   return this->plt_section()->address() + gsym->plt_offset();
2639 }
2640
2641 // Return a string used to fill a code section with nops to take up
2642 // the specified length.
2643
2644 std::string
2645 Target_i386::do_code_fill(section_size_type length) const
2646 {
2647   if (length >= 16)
2648     {
2649       // Build a jmp instruction to skip over the bytes.
2650       unsigned char jmp[5];
2651       jmp[0] = 0xe9;
2652       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2653       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2654               + std::string(length - 5, '\0'));
2655     }
2656
2657   // Nop sequences of various lengths.
2658   const char nop1[1] = { 0x90 };                   // nop
2659   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2660   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2661   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2662   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2663                          0x00 };                   // leal 0(%esi,1),%esi
2664   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2665                          0x00, 0x00 };
2666   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2667                          0x00, 0x00, 0x00 };
2668   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2669                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2670   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2671                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2672                          0x00 };
2673   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2674                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2675                            0x00, 0x00 };
2676   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2677                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2678                            0x00, 0x00, 0x00 };
2679   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2680                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2681                            0x00, 0x00, 0x00, 0x00 };
2682   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2683                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2684                            0x27, 0x00, 0x00, 0x00,
2685                            0x00 };
2686   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2687                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2688                            0xbc, 0x27, 0x00, 0x00,
2689                            0x00, 0x00 };
2690   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2691                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2692                            0x90, 0x90, 0x90, 0x90,
2693                            0x90, 0x90, 0x90 };
2694
2695   const char* nops[16] = {
2696     NULL,
2697     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2698     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2699   };
2700
2701   return std::string(nops[length], length);
2702 }
2703
2704 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2705 // compiled with -fstack-split.  The function calls non-stack-split
2706 // code.  We have to change the function so that it always ensures
2707 // that it has enough stack space to run some random function.
2708
2709 void
2710 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2711                                 section_offset_type fnoffset,
2712                                 section_size_type fnsize,
2713                                 unsigned char* view,
2714                                 section_size_type view_size,
2715                                 std::string* from,
2716                                 std::string* to) const
2717 {
2718   // The function starts with a comparison of the stack pointer and a
2719   // field in the TCB.  This is followed by a jump.
2720
2721   // cmp %gs:NN,%esp
2722   if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2723       && fnsize > 7)
2724     {
2725       // We will call __morestack if the carry flag is set after this
2726       // comparison.  We turn the comparison into an stc instruction
2727       // and some nops.
2728       view[fnoffset] = '\xf9';
2729       this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2730     }
2731   // lea NN(%esp),%ecx
2732   // lea NN(%esp),%edx
2733   else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2734             || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
2735            && fnsize > 7)
2736     {
2737       // This is loading an offset from the stack pointer for a
2738       // comparison.  The offset is negative, so we decrease the
2739       // offset by the amount of space we need for the stack.  This
2740       // means we will avoid calling __morestack if there happens to
2741       // be plenty of space on the stack already.
2742       unsigned char* pval = view + fnoffset + 3;
2743       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2744       val -= parameters->options().split_stack_adjust_size();
2745       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2746     }
2747   else
2748     {
2749       if (!object->has_no_split_stack())
2750         object->error(_("failed to match split-stack sequence at "
2751                         "section %u offset %0zx"),
2752                       shndx, static_cast<size_t>(fnoffset));
2753       return;
2754     }
2755
2756   // We have to change the function so that it calls
2757   // __morestack_non_split instead of __morestack.  The former will
2758   // allocate additional stack space.
2759   *from = "__morestack";
2760   *to = "__morestack_non_split";
2761 }
2762
2763 // The selector for i386 object files.
2764
2765 class Target_selector_i386 : public Target_selector_freebsd
2766 {
2767 public:
2768   Target_selector_i386()
2769     : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2770                               "elf32-i386", "elf32-i386-freebsd")
2771   { }
2772
2773   Target*
2774   do_instantiate_target()
2775   { return new Target_i386(); }
2776 };
2777
2778 Target_selector_i386 target_selector_i386;
2779
2780 } // End anonymous namespace.