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